linux/kernel/trace/trace_events.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * event tracer
   4 *
   5 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   6 *
   7 *  - Added format output of fields of the trace point.
   8 *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   9 *
  10 */
  11
  12#define pr_fmt(fmt) fmt
  13
  14#include <linux/workqueue.h>
  15#include <linux/security.h>
  16#include <linux/spinlock.h>
  17#include <linux/kthread.h>
  18#include <linux/tracefs.h>
  19#include <linux/uaccess.h>
  20#include <linux/module.h>
  21#include <linux/ctype.h>
  22#include <linux/sort.h>
  23#include <linux/slab.h>
  24#include <linux/delay.h>
  25
  26#include <trace/events/sched.h>
  27#include <trace/syscall.h>
  28
  29#include <asm/setup.h>
  30
  31#include "trace_output.h"
  32
  33#undef TRACE_SYSTEM
  34#define TRACE_SYSTEM "TRACE_SYSTEM"
  35
  36DEFINE_MUTEX(event_mutex);
  37
  38LIST_HEAD(ftrace_events);
  39static LIST_HEAD(ftrace_generic_fields);
  40static LIST_HEAD(ftrace_common_fields);
  41static bool eventdir_initialized;
  42
  43#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
  44
  45static struct kmem_cache *field_cachep;
  46static struct kmem_cache *file_cachep;
  47
  48static inline int system_refcount(struct event_subsystem *system)
  49{
  50        return system->ref_count;
  51}
  52
  53static int system_refcount_inc(struct event_subsystem *system)
  54{
  55        return system->ref_count++;
  56}
  57
  58static int system_refcount_dec(struct event_subsystem *system)
  59{
  60        return --system->ref_count;
  61}
  62
  63/* Double loops, do not use break, only goto's work */
  64#define do_for_each_event_file(tr, file)                        \
  65        list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  66                list_for_each_entry(file, &tr->events, list)
  67
  68#define do_for_each_event_file_safe(tr, file)                   \
  69        list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  70                struct trace_event_file *___n;                          \
  71                list_for_each_entry_safe(file, ___n, &tr->events, list)
  72
  73#define while_for_each_event_file()             \
  74        }
  75
  76static struct ftrace_event_field *
  77__find_event_field(struct list_head *head, char *name)
  78{
  79        struct ftrace_event_field *field;
  80
  81        list_for_each_entry(field, head, link) {
  82                if (!strcmp(field->name, name))
  83                        return field;
  84        }
  85
  86        return NULL;
  87}
  88
  89struct ftrace_event_field *
  90trace_find_event_field(struct trace_event_call *call, char *name)
  91{
  92        struct ftrace_event_field *field;
  93        struct list_head *head;
  94
  95        head = trace_get_fields(call);
  96        field = __find_event_field(head, name);
  97        if (field)
  98                return field;
  99
 100        field = __find_event_field(&ftrace_generic_fields, name);
 101        if (field)
 102                return field;
 103
 104        return __find_event_field(&ftrace_common_fields, name);
 105}
 106
 107static int __trace_define_field(struct list_head *head, const char *type,
 108                                const char *name, int offset, int size,
 109                                int is_signed, int filter_type)
 110{
 111        struct ftrace_event_field *field;
 112
 113        field = kmem_cache_alloc(field_cachep, GFP_TRACE);
 114        if (!field)
 115                return -ENOMEM;
 116
 117        field->name = name;
 118        field->type = type;
 119
 120        if (filter_type == FILTER_OTHER)
 121                field->filter_type = filter_assign_type(type);
 122        else
 123                field->filter_type = filter_type;
 124
 125        field->offset = offset;
 126        field->size = size;
 127        field->is_signed = is_signed;
 128
 129        list_add(&field->link, head);
 130
 131        return 0;
 132}
 133
 134int trace_define_field(struct trace_event_call *call, const char *type,
 135                       const char *name, int offset, int size, int is_signed,
 136                       int filter_type)
 137{
 138        struct list_head *head;
 139
 140        if (WARN_ON(!call->class))
 141                return 0;
 142
 143        head = trace_get_fields(call);
 144        return __trace_define_field(head, type, name, offset, size,
 145                                    is_signed, filter_type);
 146}
 147EXPORT_SYMBOL_GPL(trace_define_field);
 148
 149#define __generic_field(type, item, filter_type)                        \
 150        ret = __trace_define_field(&ftrace_generic_fields, #type,       \
 151                                   #item, 0, 0, is_signed_type(type),   \
 152                                   filter_type);                        \
 153        if (ret)                                                        \
 154                return ret;
 155
 156#define __common_field(type, item)                                      \
 157        ret = __trace_define_field(&ftrace_common_fields, #type,        \
 158                                   "common_" #item,                     \
 159                                   offsetof(typeof(ent), item),         \
 160                                   sizeof(ent.item),                    \
 161                                   is_signed_type(type), FILTER_OTHER); \
 162        if (ret)                                                        \
 163                return ret;
 164
 165static int trace_define_generic_fields(void)
 166{
 167        int ret;
 168
 169        __generic_field(int, CPU, FILTER_CPU);
 170        __generic_field(int, cpu, FILTER_CPU);
 171        __generic_field(char *, COMM, FILTER_COMM);
 172        __generic_field(char *, comm, FILTER_COMM);
 173
 174        return ret;
 175}
 176
 177static int trace_define_common_fields(void)
 178{
 179        int ret;
 180        struct trace_entry ent;
 181
 182        __common_field(unsigned short, type);
 183        __common_field(unsigned char, flags);
 184        __common_field(unsigned char, preempt_count);
 185        __common_field(int, pid);
 186
 187        return ret;
 188}
 189
 190static void trace_destroy_fields(struct trace_event_call *call)
 191{
 192        struct ftrace_event_field *field, *next;
 193        struct list_head *head;
 194
 195        head = trace_get_fields(call);
 196        list_for_each_entry_safe(field, next, head, link) {
 197                list_del(&field->link);
 198                kmem_cache_free(field_cachep, field);
 199        }
 200}
 201
 202/*
 203 * run-time version of trace_event_get_offsets_<call>() that returns the last
 204 * accessible offset of trace fields excluding __dynamic_array bytes
 205 */
 206int trace_event_get_offsets(struct trace_event_call *call)
 207{
 208        struct ftrace_event_field *tail;
 209        struct list_head *head;
 210
 211        head = trace_get_fields(call);
 212        /*
 213         * head->next points to the last field with the largest offset,
 214         * since it was added last by trace_define_field()
 215         */
 216        tail = list_first_entry(head, struct ftrace_event_field, link);
 217        return tail->offset + tail->size;
 218}
 219
 220/*
 221 * Check if the referenced field is an array and return true,
 222 * as arrays are OK to dereference.
 223 */
 224static bool test_field(const char *fmt, struct trace_event_call *call)
 225{
 226        struct trace_event_fields *field = call->class->fields_array;
 227        const char *array_descriptor;
 228        const char *p = fmt;
 229        int len;
 230
 231        if (!(len = str_has_prefix(fmt, "REC->")))
 232                return false;
 233        fmt += len;
 234        for (p = fmt; *p; p++) {
 235                if (!isalnum(*p) && *p != '_')
 236                        break;
 237        }
 238        len = p - fmt;
 239
 240        for (; field->type; field++) {
 241                if (strncmp(field->name, fmt, len) ||
 242                    field->name[len])
 243                        continue;
 244                array_descriptor = strchr(field->type, '[');
 245                /* This is an array and is OK to dereference. */
 246                return array_descriptor != NULL;
 247        }
 248        return false;
 249}
 250
 251/*
 252 * Examine the print fmt of the event looking for unsafe dereference
 253 * pointers using %p* that could be recorded in the trace event and
 254 * much later referenced after the pointer was freed. Dereferencing
 255 * pointers are OK, if it is dereferenced into the event itself.
 256 */
 257static void test_event_printk(struct trace_event_call *call)
 258{
 259        u64 dereference_flags = 0;
 260        bool first = true;
 261        const char *fmt, *c, *r, *a;
 262        int parens = 0;
 263        char in_quote = 0;
 264        int start_arg = 0;
 265        int arg = 0;
 266        int i;
 267
 268        fmt = call->print_fmt;
 269
 270        if (!fmt)
 271                return;
 272
 273        for (i = 0; fmt[i]; i++) {
 274                switch (fmt[i]) {
 275                case '\\':
 276                        i++;
 277                        if (!fmt[i])
 278                                return;
 279                        continue;
 280                case '"':
 281                case '\'':
 282                        /*
 283                         * The print fmt starts with a string that
 284                         * is processed first to find %p* usage,
 285                         * then after the first string, the print fmt
 286                         * contains arguments that are used to check
 287                         * if the dereferenced %p* usage is safe.
 288                         */
 289                        if (first) {
 290                                if (fmt[i] == '\'')
 291                                        continue;
 292                                if (in_quote) {
 293                                        arg = 0;
 294                                        first = false;
 295                                        /*
 296                                         * If there was no %p* uses
 297                                         * the fmt is OK.
 298                                         */
 299                                        if (!dereference_flags)
 300                                                return;
 301                                }
 302                        }
 303                        if (in_quote) {
 304                                if (in_quote == fmt[i])
 305                                        in_quote = 0;
 306                        } else {
 307                                in_quote = fmt[i];
 308                        }
 309                        continue;
 310                case '%':
 311                        if (!first || !in_quote)
 312                                continue;
 313                        i++;
 314                        if (!fmt[i])
 315                                return;
 316                        switch (fmt[i]) {
 317                        case '%':
 318                                continue;
 319                        case 'p':
 320                                /* Find dereferencing fields */
 321                                switch (fmt[i + 1]) {
 322                                case 'B': case 'R': case 'r':
 323                                case 'b': case 'M': case 'm':
 324                                case 'I': case 'i': case 'E':
 325                                case 'U': case 'V': case 'N':
 326                                case 'a': case 'd': case 'D':
 327                                case 'g': case 't': case 'C':
 328                                case 'O': case 'f':
 329                                        if (WARN_ONCE(arg == 63,
 330                                                      "Too many args for event: %s",
 331                                                      trace_event_name(call)))
 332                                                return;
 333                                        dereference_flags |= 1ULL << arg;
 334                                }
 335                                break;
 336                        default:
 337                        {
 338                                bool star = false;
 339                                int j;
 340
 341                                /* Increment arg if %*s exists. */
 342                                for (j = 0; fmt[i + j]; j++) {
 343                                        if (isdigit(fmt[i + j]) ||
 344                                            fmt[i + j] == '.')
 345                                                continue;
 346                                        if (fmt[i + j] == '*') {
 347                                                star = true;
 348                                                continue;
 349                                        }
 350                                        if ((fmt[i + j] == 's') && star)
 351                                                arg++;
 352                                        break;
 353                                }
 354                                break;
 355                        } /* default */
 356
 357                        } /* switch */
 358                        arg++;
 359                        continue;
 360                case '(':
 361                        if (in_quote)
 362                                continue;
 363                        parens++;
 364                        continue;
 365                case ')':
 366                        if (in_quote)
 367                                continue;
 368                        parens--;
 369                        if (WARN_ONCE(parens < 0,
 370                                      "Paren mismatch for event: %s\narg='%s'\n%*s",
 371                                      trace_event_name(call),
 372                                      fmt + start_arg,
 373                                      (i - start_arg) + 5, "^"))
 374                                return;
 375                        continue;
 376                case ',':
 377                        if (in_quote || parens)
 378                                continue;
 379                        i++;
 380                        while (isspace(fmt[i]))
 381                                i++;
 382                        start_arg = i;
 383                        if (!(dereference_flags & (1ULL << arg)))
 384                                goto next_arg;
 385
 386                        /* Find the REC-> in the argument */
 387                        c = strchr(fmt + i, ',');
 388                        r = strstr(fmt + i, "REC->");
 389                        if (r && (!c || r < c)) {
 390                                /*
 391                                 * Addresses of events on the buffer,
 392                                 * or an array on the buffer is
 393                                 * OK to dereference.
 394                                 * There's ways to fool this, but
 395                                 * this is to catch common mistakes,
 396                                 * not malicious code.
 397                                 */
 398                                a = strchr(fmt + i, '&');
 399                                if ((a && (a < r)) || test_field(r, call))
 400                                        dereference_flags &= ~(1ULL << arg);
 401                        }
 402                next_arg:
 403                        i--;
 404                        arg++;
 405                }
 406        }
 407
 408        /*
 409         * If you triggered the below warning, the trace event reported
 410         * uses an unsafe dereference pointer %p*. As the data stored
 411         * at the trace event time may no longer exist when the trace
 412         * event is printed, dereferencing to the original source is
 413         * unsafe. The source of the dereference must be copied into the
 414         * event itself, and the dereference must access the copy instead.
 415         */
 416        if (WARN_ON_ONCE(dereference_flags)) {
 417                arg = 1;
 418                while (!(dereference_flags & 1)) {
 419                        dereference_flags >>= 1;
 420                        arg++;
 421                }
 422                pr_warn("event %s has unsafe dereference of argument %d\n",
 423                        trace_event_name(call), arg);
 424                pr_warn("print_fmt: %s\n", fmt);
 425        }
 426}
 427
 428int trace_event_raw_init(struct trace_event_call *call)
 429{
 430        int id;
 431
 432        id = register_trace_event(&call->event);
 433        if (!id)
 434                return -ENODEV;
 435
 436        test_event_printk(call);
 437
 438        return 0;
 439}
 440EXPORT_SYMBOL_GPL(trace_event_raw_init);
 441
 442bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 443{
 444        struct trace_array *tr = trace_file->tr;
 445        struct trace_array_cpu *data;
 446        struct trace_pid_list *no_pid_list;
 447        struct trace_pid_list *pid_list;
 448
 449        pid_list = rcu_dereference_raw(tr->filtered_pids);
 450        no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 451
 452        if (!pid_list && !no_pid_list)
 453                return false;
 454
 455        data = this_cpu_ptr(tr->array_buffer.data);
 456
 457        return data->ignore_pid;
 458}
 459EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 460
 461void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 462                                 struct trace_event_file *trace_file,
 463                                 unsigned long len)
 464{
 465        struct trace_event_call *event_call = trace_file->event_call;
 466
 467        if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 468            trace_event_ignore_this_pid(trace_file))
 469                return NULL;
 470
 471        /*
 472         * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
 473         * preemption (adding one to the preempt_count). Since we are
 474         * interested in the preempt_count at the time the tracepoint was
 475         * hit, we need to subtract one to offset the increment.
 476         */
 477        fbuffer->trace_ctx = tracing_gen_ctx_dec();
 478        fbuffer->trace_file = trace_file;
 479
 480        fbuffer->event =
 481                trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 482                                                event_call->event.type, len,
 483                                                fbuffer->trace_ctx);
 484        if (!fbuffer->event)
 485                return NULL;
 486
 487        fbuffer->regs = NULL;
 488        fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 489        return fbuffer->entry;
 490}
 491EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 492
 493int trace_event_reg(struct trace_event_call *call,
 494                    enum trace_reg type, void *data)
 495{
 496        struct trace_event_file *file = data;
 497
 498        WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 499        switch (type) {
 500        case TRACE_REG_REGISTER:
 501                return tracepoint_probe_register(call->tp,
 502                                                 call->class->probe,
 503                                                 file);
 504        case TRACE_REG_UNREGISTER:
 505                tracepoint_probe_unregister(call->tp,
 506                                            call->class->probe,
 507                                            file);
 508                return 0;
 509
 510#ifdef CONFIG_PERF_EVENTS
 511        case TRACE_REG_PERF_REGISTER:
 512                return tracepoint_probe_register(call->tp,
 513                                                 call->class->perf_probe,
 514                                                 call);
 515        case TRACE_REG_PERF_UNREGISTER:
 516                tracepoint_probe_unregister(call->tp,
 517                                            call->class->perf_probe,
 518                                            call);
 519                return 0;
 520        case TRACE_REG_PERF_OPEN:
 521        case TRACE_REG_PERF_CLOSE:
 522        case TRACE_REG_PERF_ADD:
 523        case TRACE_REG_PERF_DEL:
 524                return 0;
 525#endif
 526        }
 527        return 0;
 528}
 529EXPORT_SYMBOL_GPL(trace_event_reg);
 530
 531void trace_event_enable_cmd_record(bool enable)
 532{
 533        struct trace_event_file *file;
 534        struct trace_array *tr;
 535
 536        lockdep_assert_held(&event_mutex);
 537
 538        do_for_each_event_file(tr, file) {
 539
 540                if (!(file->flags & EVENT_FILE_FL_ENABLED))
 541                        continue;
 542
 543                if (enable) {
 544                        tracing_start_cmdline_record();
 545                        set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 546                } else {
 547                        tracing_stop_cmdline_record();
 548                        clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 549                }
 550        } while_for_each_event_file();
 551}
 552
 553void trace_event_enable_tgid_record(bool enable)
 554{
 555        struct trace_event_file *file;
 556        struct trace_array *tr;
 557
 558        lockdep_assert_held(&event_mutex);
 559
 560        do_for_each_event_file(tr, file) {
 561                if (!(file->flags & EVENT_FILE_FL_ENABLED))
 562                        continue;
 563
 564                if (enable) {
 565                        tracing_start_tgid_record();
 566                        set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 567                } else {
 568                        tracing_stop_tgid_record();
 569                        clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 570                                  &file->flags);
 571                }
 572        } while_for_each_event_file();
 573}
 574
 575static int __ftrace_event_enable_disable(struct trace_event_file *file,
 576                                         int enable, int soft_disable)
 577{
 578        struct trace_event_call *call = file->event_call;
 579        struct trace_array *tr = file->tr;
 580        unsigned long file_flags = file->flags;
 581        int ret = 0;
 582        int disable;
 583
 584        switch (enable) {
 585        case 0:
 586                /*
 587                 * When soft_disable is set and enable is cleared, the sm_ref
 588                 * reference counter is decremented. If it reaches 0, we want
 589                 * to clear the SOFT_DISABLED flag but leave the event in the
 590                 * state that it was. That is, if the event was enabled and
 591                 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 592                 * is set we do not want the event to be enabled before we
 593                 * clear the bit.
 594                 *
 595                 * When soft_disable is not set but the SOFT_MODE flag is,
 596                 * we do nothing. Do not disable the tracepoint, otherwise
 597                 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 598                 */
 599                if (soft_disable) {
 600                        if (atomic_dec_return(&file->sm_ref) > 0)
 601                                break;
 602                        disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 603                        clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 604                } else
 605                        disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 606
 607                if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 608                        clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 609                        if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 610                                tracing_stop_cmdline_record();
 611                                clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 612                        }
 613
 614                        if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 615                                tracing_stop_tgid_record();
 616                                clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 617                        }
 618
 619                        call->class->reg(call, TRACE_REG_UNREGISTER, file);
 620                }
 621                /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 622                if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 623                        set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 624                else
 625                        clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 626                break;
 627        case 1:
 628                /*
 629                 * When soft_disable is set and enable is set, we want to
 630                 * register the tracepoint for the event, but leave the event
 631                 * as is. That means, if the event was already enabled, we do
 632                 * nothing (but set SOFT_MODE). If the event is disabled, we
 633                 * set SOFT_DISABLED before enabling the event tracepoint, so
 634                 * it still seems to be disabled.
 635                 */
 636                if (!soft_disable)
 637                        clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 638                else {
 639                        if (atomic_inc_return(&file->sm_ref) > 1)
 640                                break;
 641                        set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 642                }
 643
 644                if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 645                        bool cmd = false, tgid = false;
 646
 647                        /* Keep the event disabled, when going to SOFT_MODE. */
 648                        if (soft_disable)
 649                                set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 650
 651                        if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 652                                cmd = true;
 653                                tracing_start_cmdline_record();
 654                                set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 655                        }
 656
 657                        if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 658                                tgid = true;
 659                                tracing_start_tgid_record();
 660                                set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 661                        }
 662
 663                        ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 664                        if (ret) {
 665                                if (cmd)
 666                                        tracing_stop_cmdline_record();
 667                                if (tgid)
 668                                        tracing_stop_tgid_record();
 669                                pr_info("event trace: Could not enable event "
 670                                        "%s\n", trace_event_name(call));
 671                                break;
 672                        }
 673                        set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 674
 675                        /* WAS_ENABLED gets set but never cleared. */
 676                        set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 677                }
 678                break;
 679        }
 680
 681        /* Enable or disable use of trace_buffered_event */
 682        if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
 683            (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
 684                if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
 685                        trace_buffered_event_enable();
 686                else
 687                        trace_buffered_event_disable();
 688        }
 689
 690        return ret;
 691}
 692
 693int trace_event_enable_disable(struct trace_event_file *file,
 694                               int enable, int soft_disable)
 695{
 696        return __ftrace_event_enable_disable(file, enable, soft_disable);
 697}
 698
 699static int ftrace_event_enable_disable(struct trace_event_file *file,
 700                                       int enable)
 701{
 702        return __ftrace_event_enable_disable(file, enable, 0);
 703}
 704
 705static void ftrace_clear_events(struct trace_array *tr)
 706{
 707        struct trace_event_file *file;
 708
 709        mutex_lock(&event_mutex);
 710        list_for_each_entry(file, &tr->events, list) {
 711                ftrace_event_enable_disable(file, 0);
 712        }
 713        mutex_unlock(&event_mutex);
 714}
 715
 716static void
 717event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 718{
 719        struct trace_pid_list *pid_list;
 720        struct trace_array *tr = data;
 721
 722        pid_list = rcu_dereference_raw(tr->filtered_pids);
 723        trace_filter_add_remove_task(pid_list, NULL, task);
 724
 725        pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 726        trace_filter_add_remove_task(pid_list, NULL, task);
 727}
 728
 729static void
 730event_filter_pid_sched_process_fork(void *data,
 731                                    struct task_struct *self,
 732                                    struct task_struct *task)
 733{
 734        struct trace_pid_list *pid_list;
 735        struct trace_array *tr = data;
 736
 737        pid_list = rcu_dereference_sched(tr->filtered_pids);
 738        trace_filter_add_remove_task(pid_list, self, task);
 739
 740        pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 741        trace_filter_add_remove_task(pid_list, self, task);
 742}
 743
 744void trace_event_follow_fork(struct trace_array *tr, bool enable)
 745{
 746        if (enable) {
 747                register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 748                                                       tr, INT_MIN);
 749                register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 750                                                       tr, INT_MAX);
 751        } else {
 752                unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 753                                                    tr);
 754                unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 755                                                    tr);
 756        }
 757}
 758
 759static void
 760event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 761                    struct task_struct *prev, struct task_struct *next)
 762{
 763        struct trace_array *tr = data;
 764        struct trace_pid_list *no_pid_list;
 765        struct trace_pid_list *pid_list;
 766        bool ret;
 767
 768        pid_list = rcu_dereference_sched(tr->filtered_pids);
 769        no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 770
 771        /*
 772         * Sched switch is funny, as we only want to ignore it
 773         * in the notrace case if both prev and next should be ignored.
 774         */
 775        ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
 776                trace_ignore_this_task(NULL, no_pid_list, next);
 777
 778        this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
 779                       (trace_ignore_this_task(pid_list, NULL, prev) &&
 780                        trace_ignore_this_task(pid_list, NULL, next)));
 781}
 782
 783static void
 784event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 785                    struct task_struct *prev, struct task_struct *next)
 786{
 787        struct trace_array *tr = data;
 788        struct trace_pid_list *no_pid_list;
 789        struct trace_pid_list *pid_list;
 790
 791        pid_list = rcu_dereference_sched(tr->filtered_pids);
 792        no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 793
 794        this_cpu_write(tr->array_buffer.data->ignore_pid,
 795                       trace_ignore_this_task(pid_list, no_pid_list, next));
 796}
 797
 798static void
 799event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 800{
 801        struct trace_array *tr = data;
 802        struct trace_pid_list *no_pid_list;
 803        struct trace_pid_list *pid_list;
 804
 805        /* Nothing to do if we are already tracing */
 806        if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 807                return;
 808
 809        pid_list = rcu_dereference_sched(tr->filtered_pids);
 810        no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 811
 812        this_cpu_write(tr->array_buffer.data->ignore_pid,
 813                       trace_ignore_this_task(pid_list, no_pid_list, task));
 814}
 815
 816static void
 817event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 818{
 819        struct trace_array *tr = data;
 820        struct trace_pid_list *no_pid_list;
 821        struct trace_pid_list *pid_list;
 822
 823        /* Nothing to do if we are not tracing */
 824        if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 825                return;
 826
 827        pid_list = rcu_dereference_sched(tr->filtered_pids);
 828        no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 829
 830        /* Set tracing if current is enabled */
 831        this_cpu_write(tr->array_buffer.data->ignore_pid,
 832                       trace_ignore_this_task(pid_list, no_pid_list, current));
 833}
 834
 835static void unregister_pid_events(struct trace_array *tr)
 836{
 837        unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 838        unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 839
 840        unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 841        unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 842
 843        unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 844        unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 845
 846        unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 847        unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 848}
 849
 850static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
 851{
 852        struct trace_pid_list *pid_list;
 853        struct trace_pid_list *no_pid_list;
 854        struct trace_event_file *file;
 855        int cpu;
 856
 857        pid_list = rcu_dereference_protected(tr->filtered_pids,
 858                                             lockdep_is_held(&event_mutex));
 859        no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
 860                                             lockdep_is_held(&event_mutex));
 861
 862        /* Make sure there's something to do */
 863        if (!pid_type_enabled(type, pid_list, no_pid_list))
 864                return;
 865
 866        if (!still_need_pid_events(type, pid_list, no_pid_list)) {
 867                unregister_pid_events(tr);
 868
 869                list_for_each_entry(file, &tr->events, list) {
 870                        clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 871                }
 872
 873                for_each_possible_cpu(cpu)
 874                        per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 875        }
 876
 877        if (type & TRACE_PIDS)
 878                rcu_assign_pointer(tr->filtered_pids, NULL);
 879
 880        if (type & TRACE_NO_PIDS)
 881                rcu_assign_pointer(tr->filtered_no_pids, NULL);
 882
 883        /* Wait till all users are no longer using pid filtering */
 884        tracepoint_synchronize_unregister();
 885
 886        if ((type & TRACE_PIDS) && pid_list)
 887                trace_free_pid_list(pid_list);
 888
 889        if ((type & TRACE_NO_PIDS) && no_pid_list)
 890                trace_free_pid_list(no_pid_list);
 891}
 892
 893static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 894{
 895        mutex_lock(&event_mutex);
 896        __ftrace_clear_event_pids(tr, type);
 897        mutex_unlock(&event_mutex);
 898}
 899
 900static void __put_system(struct event_subsystem *system)
 901{
 902        struct event_filter *filter = system->filter;
 903
 904        WARN_ON_ONCE(system_refcount(system) == 0);
 905        if (system_refcount_dec(system))
 906                return;
 907
 908        list_del(&system->list);
 909
 910        if (filter) {
 911                kfree(filter->filter_string);
 912                kfree(filter);
 913        }
 914        kfree_const(system->name);
 915        kfree(system);
 916}
 917
 918static void __get_system(struct event_subsystem *system)
 919{
 920        WARN_ON_ONCE(system_refcount(system) == 0);
 921        system_refcount_inc(system);
 922}
 923
 924static void __get_system_dir(struct trace_subsystem_dir *dir)
 925{
 926        WARN_ON_ONCE(dir->ref_count == 0);
 927        dir->ref_count++;
 928        __get_system(dir->subsystem);
 929}
 930
 931static void __put_system_dir(struct trace_subsystem_dir *dir)
 932{
 933        WARN_ON_ONCE(dir->ref_count == 0);
 934        /* If the subsystem is about to be freed, the dir must be too */
 935        WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 936
 937        __put_system(dir->subsystem);
 938        if (!--dir->ref_count)
 939                kfree(dir);
 940}
 941
 942static void put_system(struct trace_subsystem_dir *dir)
 943{
 944        mutex_lock(&event_mutex);
 945        __put_system_dir(dir);
 946        mutex_unlock(&event_mutex);
 947}
 948
 949static void remove_subsystem(struct trace_subsystem_dir *dir)
 950{
 951        if (!dir)
 952                return;
 953
 954        if (!--dir->nr_events) {
 955                tracefs_remove(dir->entry);
 956                list_del(&dir->list);
 957                __put_system_dir(dir);
 958        }
 959}
 960
 961static void remove_event_file_dir(struct trace_event_file *file)
 962{
 963        struct dentry *dir = file->dir;
 964        struct dentry *child;
 965
 966        if (dir) {
 967                spin_lock(&dir->d_lock);        /* probably unneeded */
 968                list_for_each_entry(child, &dir->d_subdirs, d_child) {
 969                        if (d_really_is_positive(child))        /* probably unneeded */
 970                                d_inode(child)->i_private = NULL;
 971                }
 972                spin_unlock(&dir->d_lock);
 973
 974                tracefs_remove(dir);
 975        }
 976
 977        list_del(&file->list);
 978        remove_subsystem(file->system);
 979        free_event_filter(file->filter);
 980        kmem_cache_free(file_cachep, file);
 981}
 982
 983/*
 984 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 985 */
 986static int
 987__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
 988                              const char *sub, const char *event, int set)
 989{
 990        struct trace_event_file *file;
 991        struct trace_event_call *call;
 992        const char *name;
 993        int ret = -EINVAL;
 994        int eret = 0;
 995
 996        list_for_each_entry(file, &tr->events, list) {
 997
 998                call = file->event_call;
 999                name = trace_event_name(call);
1000
1001                if (!name || !call->class || !call->class->reg)
1002                        continue;
1003
1004                if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1005                        continue;
1006
1007                if (match &&
1008                    strcmp(match, name) != 0 &&
1009                    strcmp(match, call->class->system) != 0)
1010                        continue;
1011
1012                if (sub && strcmp(sub, call->class->system) != 0)
1013                        continue;
1014
1015                if (event && strcmp(event, name) != 0)
1016                        continue;
1017
1018                ret = ftrace_event_enable_disable(file, set);
1019
1020                /*
1021                 * Save the first error and return that. Some events
1022                 * may still have been enabled, but let the user
1023                 * know that something went wrong.
1024                 */
1025                if (ret && !eret)
1026                        eret = ret;
1027
1028                ret = eret;
1029        }
1030
1031        return ret;
1032}
1033
1034static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1035                                  const char *sub, const char *event, int set)
1036{
1037        int ret;
1038
1039        mutex_lock(&event_mutex);
1040        ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1041        mutex_unlock(&event_mutex);
1042
1043        return ret;
1044}
1045
1046int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1047{
1048        char *event = NULL, *sub = NULL, *match;
1049        int ret;
1050
1051        if (!tr)
1052                return -ENOENT;
1053        /*
1054         * The buf format can be <subsystem>:<event-name>
1055         *  *:<event-name> means any event by that name.
1056         *  :<event-name> is the same.
1057         *
1058         *  <subsystem>:* means all events in that subsystem
1059         *  <subsystem>: means the same.
1060         *
1061         *  <name> (no ':') means all events in a subsystem with
1062         *  the name <name> or any event that matches <name>
1063         */
1064
1065        match = strsep(&buf, ":");
1066        if (buf) {
1067                sub = match;
1068                event = buf;
1069                match = NULL;
1070
1071                if (!strlen(sub) || strcmp(sub, "*") == 0)
1072                        sub = NULL;
1073                if (!strlen(event) || strcmp(event, "*") == 0)
1074                        event = NULL;
1075        }
1076
1077        ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1078
1079        /* Put back the colon to allow this to be called again */
1080        if (buf)
1081                *(buf - 1) = ':';
1082
1083        return ret;
1084}
1085
1086/**
1087 * trace_set_clr_event - enable or disable an event
1088 * @system: system name to match (NULL for any system)
1089 * @event: event name to match (NULL for all events, within system)
1090 * @set: 1 to enable, 0 to disable
1091 *
1092 * This is a way for other parts of the kernel to enable or disable
1093 * event recording.
1094 *
1095 * Returns 0 on success, -EINVAL if the parameters do not match any
1096 * registered events.
1097 */
1098int trace_set_clr_event(const char *system, const char *event, int set)
1099{
1100        struct trace_array *tr = top_trace_array();
1101
1102        if (!tr)
1103                return -ENODEV;
1104
1105        return __ftrace_set_clr_event(tr, NULL, system, event, set);
1106}
1107EXPORT_SYMBOL_GPL(trace_set_clr_event);
1108
1109/**
1110 * trace_array_set_clr_event - enable or disable an event for a trace array.
1111 * @tr: concerned trace array.
1112 * @system: system name to match (NULL for any system)
1113 * @event: event name to match (NULL for all events, within system)
1114 * @enable: true to enable, false to disable
1115 *
1116 * This is a way for other parts of the kernel to enable or disable
1117 * event recording.
1118 *
1119 * Returns 0 on success, -EINVAL if the parameters do not match any
1120 * registered events.
1121 */
1122int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1123                const char *event, bool enable)
1124{
1125        int set;
1126
1127        if (!tr)
1128                return -ENOENT;
1129
1130        set = (enable == true) ? 1 : 0;
1131        return __ftrace_set_clr_event(tr, NULL, system, event, set);
1132}
1133EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1134
1135/* 128 should be much more than enough */
1136#define EVENT_BUF_SIZE          127
1137
1138static ssize_t
1139ftrace_event_write(struct file *file, const char __user *ubuf,
1140                   size_t cnt, loff_t *ppos)
1141{
1142        struct trace_parser parser;
1143        struct seq_file *m = file->private_data;
1144        struct trace_array *tr = m->private;
1145        ssize_t read, ret;
1146
1147        if (!cnt)
1148                return 0;
1149
1150        ret = tracing_update_buffers();
1151        if (ret < 0)
1152                return ret;
1153
1154        if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1155                return -ENOMEM;
1156
1157        read = trace_get_user(&parser, ubuf, cnt, ppos);
1158
1159        if (read >= 0 && trace_parser_loaded((&parser))) {
1160                int set = 1;
1161
1162                if (*parser.buffer == '!')
1163                        set = 0;
1164
1165                ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1166                if (ret)
1167                        goto out_put;
1168        }
1169
1170        ret = read;
1171
1172 out_put:
1173        trace_parser_put(&parser);
1174
1175        return ret;
1176}
1177
1178static void *
1179t_next(struct seq_file *m, void *v, loff_t *pos)
1180{
1181        struct trace_event_file *file = v;
1182        struct trace_event_call *call;
1183        struct trace_array *tr = m->private;
1184
1185        (*pos)++;
1186
1187        list_for_each_entry_continue(file, &tr->events, list) {
1188                call = file->event_call;
1189                /*
1190                 * The ftrace subsystem is for showing formats only.
1191                 * They can not be enabled or disabled via the event files.
1192                 */
1193                if (call->class && call->class->reg &&
1194                    !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1195                        return file;
1196        }
1197
1198        return NULL;
1199}
1200
1201static void *t_start(struct seq_file *m, loff_t *pos)
1202{
1203        struct trace_event_file *file;
1204        struct trace_array *tr = m->private;
1205        loff_t l;
1206
1207        mutex_lock(&event_mutex);
1208
1209        file = list_entry(&tr->events, struct trace_event_file, list);
1210        for (l = 0; l <= *pos; ) {
1211                file = t_next(m, file, &l);
1212                if (!file)
1213                        break;
1214        }
1215        return file;
1216}
1217
1218static void *
1219s_next(struct seq_file *m, void *v, loff_t *pos)
1220{
1221        struct trace_event_file *file = v;
1222        struct trace_array *tr = m->private;
1223
1224        (*pos)++;
1225
1226        list_for_each_entry_continue(file, &tr->events, list) {
1227                if (file->flags & EVENT_FILE_FL_ENABLED)
1228                        return file;
1229        }
1230
1231        return NULL;
1232}
1233
1234static void *s_start(struct seq_file *m, loff_t *pos)
1235{
1236        struct trace_event_file *file;
1237        struct trace_array *tr = m->private;
1238        loff_t l;
1239
1240        mutex_lock(&event_mutex);
1241
1242        file = list_entry(&tr->events, struct trace_event_file, list);
1243        for (l = 0; l <= *pos; ) {
1244                file = s_next(m, file, &l);
1245                if (!file)
1246                        break;
1247        }
1248        return file;
1249}
1250
1251static int t_show(struct seq_file *m, void *v)
1252{
1253        struct trace_event_file *file = v;
1254        struct trace_event_call *call = file->event_call;
1255
1256        if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1257                seq_printf(m, "%s:", call->class->system);
1258        seq_printf(m, "%s\n", trace_event_name(call));
1259
1260        return 0;
1261}
1262
1263static void t_stop(struct seq_file *m, void *p)
1264{
1265        mutex_unlock(&event_mutex);
1266}
1267
1268static void *
1269__next(struct seq_file *m, void *v, loff_t *pos, int type)
1270{
1271        struct trace_array *tr = m->private;
1272        struct trace_pid_list *pid_list;
1273
1274        if (type == TRACE_PIDS)
1275                pid_list = rcu_dereference_sched(tr->filtered_pids);
1276        else
1277                pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1278
1279        return trace_pid_next(pid_list, v, pos);
1280}
1281
1282static void *
1283p_next(struct seq_file *m, void *v, loff_t *pos)
1284{
1285        return __next(m, v, pos, TRACE_PIDS);
1286}
1287
1288static void *
1289np_next(struct seq_file *m, void *v, loff_t *pos)
1290{
1291        return __next(m, v, pos, TRACE_NO_PIDS);
1292}
1293
1294static void *__start(struct seq_file *m, loff_t *pos, int type)
1295        __acquires(RCU)
1296{
1297        struct trace_pid_list *pid_list;
1298        struct trace_array *tr = m->private;
1299
1300        /*
1301         * Grab the mutex, to keep calls to p_next() having the same
1302         * tr->filtered_pids as p_start() has.
1303         * If we just passed the tr->filtered_pids around, then RCU would
1304         * have been enough, but doing that makes things more complex.
1305         */
1306        mutex_lock(&event_mutex);
1307        rcu_read_lock_sched();
1308
1309        if (type == TRACE_PIDS)
1310                pid_list = rcu_dereference_sched(tr->filtered_pids);
1311        else
1312                pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1313
1314        if (!pid_list)
1315                return NULL;
1316
1317        return trace_pid_start(pid_list, pos);
1318}
1319
1320static void *p_start(struct seq_file *m, loff_t *pos)
1321        __acquires(RCU)
1322{
1323        return __start(m, pos, TRACE_PIDS);
1324}
1325
1326static void *np_start(struct seq_file *m, loff_t *pos)
1327        __acquires(RCU)
1328{
1329        return __start(m, pos, TRACE_NO_PIDS);
1330}
1331
1332static void p_stop(struct seq_file *m, void *p)
1333        __releases(RCU)
1334{
1335        rcu_read_unlock_sched();
1336        mutex_unlock(&event_mutex);
1337}
1338
1339static ssize_t
1340event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1341                  loff_t *ppos)
1342{
1343        struct trace_event_file *file;
1344        unsigned long flags;
1345        char buf[4] = "0";
1346
1347        mutex_lock(&event_mutex);
1348        file = event_file_data(filp);
1349        if (likely(file))
1350                flags = file->flags;
1351        mutex_unlock(&event_mutex);
1352
1353        if (!file)
1354                return -ENODEV;
1355
1356        if (flags & EVENT_FILE_FL_ENABLED &&
1357            !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1358                strcpy(buf, "1");
1359
1360        if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1361            flags & EVENT_FILE_FL_SOFT_MODE)
1362                strcat(buf, "*");
1363
1364        strcat(buf, "\n");
1365
1366        return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1367}
1368
1369static ssize_t
1370event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1371                   loff_t *ppos)
1372{
1373        struct trace_event_file *file;
1374        unsigned long val;
1375        int ret;
1376
1377        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1378        if (ret)
1379                return ret;
1380
1381        ret = tracing_update_buffers();
1382        if (ret < 0)
1383                return ret;
1384
1385        switch (val) {
1386        case 0:
1387        case 1:
1388                ret = -ENODEV;
1389                mutex_lock(&event_mutex);
1390                file = event_file_data(filp);
1391                if (likely(file))
1392                        ret = ftrace_event_enable_disable(file, val);
1393                mutex_unlock(&event_mutex);
1394                break;
1395
1396        default:
1397                return -EINVAL;
1398        }
1399
1400        *ppos += cnt;
1401
1402        return ret ? ret : cnt;
1403}
1404
1405static ssize_t
1406system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1407                   loff_t *ppos)
1408{
1409        const char set_to_char[4] = { '?', '0', '1', 'X' };
1410        struct trace_subsystem_dir *dir = filp->private_data;
1411        struct event_subsystem *system = dir->subsystem;
1412        struct trace_event_call *call;
1413        struct trace_event_file *file;
1414        struct trace_array *tr = dir->tr;
1415        char buf[2];
1416        int set = 0;
1417        int ret;
1418
1419        mutex_lock(&event_mutex);
1420        list_for_each_entry(file, &tr->events, list) {
1421                call = file->event_call;
1422                if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1423                    !trace_event_name(call) || !call->class || !call->class->reg)
1424                        continue;
1425
1426                if (system && strcmp(call->class->system, system->name) != 0)
1427                        continue;
1428
1429                /*
1430                 * We need to find out if all the events are set
1431                 * or if all events or cleared, or if we have
1432                 * a mixture.
1433                 */
1434                set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1435
1436                /*
1437                 * If we have a mixture, no need to look further.
1438                 */
1439                if (set == 3)
1440                        break;
1441        }
1442        mutex_unlock(&event_mutex);
1443
1444        buf[0] = set_to_char[set];
1445        buf[1] = '\n';
1446
1447        ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1448
1449        return ret;
1450}
1451
1452static ssize_t
1453system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1454                    loff_t *ppos)
1455{
1456        struct trace_subsystem_dir *dir = filp->private_data;
1457        struct event_subsystem *system = dir->subsystem;
1458        const char *name = NULL;
1459        unsigned long val;
1460        ssize_t ret;
1461
1462        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1463        if (ret)
1464                return ret;
1465
1466        ret = tracing_update_buffers();
1467        if (ret < 0)
1468                return ret;
1469
1470        if (val != 0 && val != 1)
1471                return -EINVAL;
1472
1473        /*
1474         * Opening of "enable" adds a ref count to system,
1475         * so the name is safe to use.
1476         */
1477        if (system)
1478                name = system->name;
1479
1480        ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1481        if (ret)
1482                goto out;
1483
1484        ret = cnt;
1485
1486out:
1487        *ppos += cnt;
1488
1489        return ret;
1490}
1491
1492enum {
1493        FORMAT_HEADER           = 1,
1494        FORMAT_FIELD_SEPERATOR  = 2,
1495        FORMAT_PRINTFMT         = 3,
1496};
1497
1498static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1499{
1500        struct trace_event_call *call = event_file_data(m->private);
1501        struct list_head *common_head = &ftrace_common_fields;
1502        struct list_head *head = trace_get_fields(call);
1503        struct list_head *node = v;
1504
1505        (*pos)++;
1506
1507        switch ((unsigned long)v) {
1508        case FORMAT_HEADER:
1509                node = common_head;
1510                break;
1511
1512        case FORMAT_FIELD_SEPERATOR:
1513                node = head;
1514                break;
1515
1516        case FORMAT_PRINTFMT:
1517                /* all done */
1518                return NULL;
1519        }
1520
1521        node = node->prev;
1522        if (node == common_head)
1523                return (void *)FORMAT_FIELD_SEPERATOR;
1524        else if (node == head)
1525                return (void *)FORMAT_PRINTFMT;
1526        else
1527                return node;
1528}
1529
1530static int f_show(struct seq_file *m, void *v)
1531{
1532        struct trace_event_call *call = event_file_data(m->private);
1533        struct ftrace_event_field *field;
1534        const char *array_descriptor;
1535
1536        switch ((unsigned long)v) {
1537        case FORMAT_HEADER:
1538                seq_printf(m, "name: %s\n", trace_event_name(call));
1539                seq_printf(m, "ID: %d\n", call->event.type);
1540                seq_puts(m, "format:\n");
1541                return 0;
1542
1543        case FORMAT_FIELD_SEPERATOR:
1544                seq_putc(m, '\n');
1545                return 0;
1546
1547        case FORMAT_PRINTFMT:
1548                seq_printf(m, "\nprint fmt: %s\n",
1549                           call->print_fmt);
1550                return 0;
1551        }
1552
1553        field = list_entry(v, struct ftrace_event_field, link);
1554        /*
1555         * Smartly shows the array type(except dynamic array).
1556         * Normal:
1557         *      field:TYPE VAR
1558         * If TYPE := TYPE[LEN], it is shown:
1559         *      field:TYPE VAR[LEN]
1560         */
1561        array_descriptor = strchr(field->type, '[');
1562
1563        if (str_has_prefix(field->type, "__data_loc"))
1564                array_descriptor = NULL;
1565
1566        if (!array_descriptor)
1567                seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1568                           field->type, field->name, field->offset,
1569                           field->size, !!field->is_signed);
1570        else
1571                seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1572                           (int)(array_descriptor - field->type),
1573                           field->type, field->name,
1574                           array_descriptor, field->offset,
1575                           field->size, !!field->is_signed);
1576
1577        return 0;
1578}
1579
1580static void *f_start(struct seq_file *m, loff_t *pos)
1581{
1582        void *p = (void *)FORMAT_HEADER;
1583        loff_t l = 0;
1584
1585        /* ->stop() is called even if ->start() fails */
1586        mutex_lock(&event_mutex);
1587        if (!event_file_data(m->private))
1588                return ERR_PTR(-ENODEV);
1589
1590        while (l < *pos && p)
1591                p = f_next(m, p, &l);
1592
1593        return p;
1594}
1595
1596static void f_stop(struct seq_file *m, void *p)
1597{
1598        mutex_unlock(&event_mutex);
1599}
1600
1601static const struct seq_operations trace_format_seq_ops = {
1602        .start          = f_start,
1603        .next           = f_next,
1604        .stop           = f_stop,
1605        .show           = f_show,
1606};
1607
1608static int trace_format_open(struct inode *inode, struct file *file)
1609{
1610        struct seq_file *m;
1611        int ret;
1612
1613        /* Do we want to hide event format files on tracefs lockdown? */
1614
1615        ret = seq_open(file, &trace_format_seq_ops);
1616        if (ret < 0)
1617                return ret;
1618
1619        m = file->private_data;
1620        m->private = file;
1621
1622        return 0;
1623}
1624
1625static ssize_t
1626event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1627{
1628        int id = (long)event_file_data(filp);
1629        char buf[32];
1630        int len;
1631
1632        if (unlikely(!id))
1633                return -ENODEV;
1634
1635        len = sprintf(buf, "%d\n", id);
1636
1637        return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1638}
1639
1640static ssize_t
1641event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1642                  loff_t *ppos)
1643{
1644        struct trace_event_file *file;
1645        struct trace_seq *s;
1646        int r = -ENODEV;
1647
1648        if (*ppos)
1649                return 0;
1650
1651        s = kmalloc(sizeof(*s), GFP_KERNEL);
1652
1653        if (!s)
1654                return -ENOMEM;
1655
1656        trace_seq_init(s);
1657
1658        mutex_lock(&event_mutex);
1659        file = event_file_data(filp);
1660        if (file)
1661                print_event_filter(file, s);
1662        mutex_unlock(&event_mutex);
1663
1664        if (file)
1665                r = simple_read_from_buffer(ubuf, cnt, ppos,
1666                                            s->buffer, trace_seq_used(s));
1667
1668        kfree(s);
1669
1670        return r;
1671}
1672
1673static ssize_t
1674event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1675                   loff_t *ppos)
1676{
1677        struct trace_event_file *file;
1678        char *buf;
1679        int err = -ENODEV;
1680
1681        if (cnt >= PAGE_SIZE)
1682                return -EINVAL;
1683
1684        buf = memdup_user_nul(ubuf, cnt);
1685        if (IS_ERR(buf))
1686                return PTR_ERR(buf);
1687
1688        mutex_lock(&event_mutex);
1689        file = event_file_data(filp);
1690        if (file)
1691                err = apply_event_filter(file, buf);
1692        mutex_unlock(&event_mutex);
1693
1694        kfree(buf);
1695        if (err < 0)
1696                return err;
1697
1698        *ppos += cnt;
1699
1700        return cnt;
1701}
1702
1703static LIST_HEAD(event_subsystems);
1704
1705static int subsystem_open(struct inode *inode, struct file *filp)
1706{
1707        struct event_subsystem *system = NULL;
1708        struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1709        struct trace_array *tr;
1710        int ret;
1711
1712        if (tracing_is_disabled())
1713                return -ENODEV;
1714
1715        /* Make sure the system still exists */
1716        mutex_lock(&event_mutex);
1717        mutex_lock(&trace_types_lock);
1718        list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1719                list_for_each_entry(dir, &tr->systems, list) {
1720                        if (dir == inode->i_private) {
1721                                /* Don't open systems with no events */
1722                                if (dir->nr_events) {
1723                                        __get_system_dir(dir);
1724                                        system = dir->subsystem;
1725                                }
1726                                goto exit_loop;
1727                        }
1728                }
1729        }
1730 exit_loop:
1731        mutex_unlock(&trace_types_lock);
1732        mutex_unlock(&event_mutex);
1733
1734        if (!system)
1735                return -ENODEV;
1736
1737        /* Some versions of gcc think dir can be uninitialized here */
1738        WARN_ON(!dir);
1739
1740        /* Still need to increment the ref count of the system */
1741        if (trace_array_get(tr) < 0) {
1742                put_system(dir);
1743                return -ENODEV;
1744        }
1745
1746        ret = tracing_open_generic(inode, filp);
1747        if (ret < 0) {
1748                trace_array_put(tr);
1749                put_system(dir);
1750        }
1751
1752        return ret;
1753}
1754
1755static int system_tr_open(struct inode *inode, struct file *filp)
1756{
1757        struct trace_subsystem_dir *dir;
1758        struct trace_array *tr = inode->i_private;
1759        int ret;
1760
1761        /* Make a temporary dir that has no system but points to tr */
1762        dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1763        if (!dir)
1764                return -ENOMEM;
1765
1766        ret = tracing_open_generic_tr(inode, filp);
1767        if (ret < 0) {
1768                kfree(dir);
1769                return ret;
1770        }
1771        dir->tr = tr;
1772        filp->private_data = dir;
1773
1774        return 0;
1775}
1776
1777static int subsystem_release(struct inode *inode, struct file *file)
1778{
1779        struct trace_subsystem_dir *dir = file->private_data;
1780
1781        trace_array_put(dir->tr);
1782
1783        /*
1784         * If dir->subsystem is NULL, then this is a temporary
1785         * descriptor that was made for a trace_array to enable
1786         * all subsystems.
1787         */
1788        if (dir->subsystem)
1789                put_system(dir);
1790        else
1791                kfree(dir);
1792
1793        return 0;
1794}
1795
1796static ssize_t
1797subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1798                      loff_t *ppos)
1799{
1800        struct trace_subsystem_dir *dir = filp->private_data;
1801        struct event_subsystem *system = dir->subsystem;
1802        struct trace_seq *s;
1803        int r;
1804
1805        if (*ppos)
1806                return 0;
1807
1808        s = kmalloc(sizeof(*s), GFP_KERNEL);
1809        if (!s)
1810                return -ENOMEM;
1811
1812        trace_seq_init(s);
1813
1814        print_subsystem_event_filter(system, s);
1815        r = simple_read_from_buffer(ubuf, cnt, ppos,
1816                                    s->buffer, trace_seq_used(s));
1817
1818        kfree(s);
1819
1820        return r;
1821}
1822
1823static ssize_t
1824subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1825                       loff_t *ppos)
1826{
1827        struct trace_subsystem_dir *dir = filp->private_data;
1828        char *buf;
1829        int err;
1830
1831        if (cnt >= PAGE_SIZE)
1832                return -EINVAL;
1833
1834        buf = memdup_user_nul(ubuf, cnt);
1835        if (IS_ERR(buf))
1836                return PTR_ERR(buf);
1837
1838        err = apply_subsystem_event_filter(dir, buf);
1839        kfree(buf);
1840        if (err < 0)
1841                return err;
1842
1843        *ppos += cnt;
1844
1845        return cnt;
1846}
1847
1848static ssize_t
1849show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1850{
1851        int (*func)(struct trace_seq *s) = filp->private_data;
1852        struct trace_seq *s;
1853        int r;
1854
1855        if (*ppos)
1856                return 0;
1857
1858        s = kmalloc(sizeof(*s), GFP_KERNEL);
1859        if (!s)
1860                return -ENOMEM;
1861
1862        trace_seq_init(s);
1863
1864        func(s);
1865        r = simple_read_from_buffer(ubuf, cnt, ppos,
1866                                    s->buffer, trace_seq_used(s));
1867
1868        kfree(s);
1869
1870        return r;
1871}
1872
1873static void ignore_task_cpu(void *data)
1874{
1875        struct trace_array *tr = data;
1876        struct trace_pid_list *pid_list;
1877        struct trace_pid_list *no_pid_list;
1878
1879        /*
1880         * This function is called by on_each_cpu() while the
1881         * event_mutex is held.
1882         */
1883        pid_list = rcu_dereference_protected(tr->filtered_pids,
1884                                             mutex_is_locked(&event_mutex));
1885        no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1886                                             mutex_is_locked(&event_mutex));
1887
1888        this_cpu_write(tr->array_buffer.data->ignore_pid,
1889                       trace_ignore_this_task(pid_list, no_pid_list, current));
1890}
1891
1892static void register_pid_events(struct trace_array *tr)
1893{
1894        /*
1895         * Register a probe that is called before all other probes
1896         * to set ignore_pid if next or prev do not match.
1897         * Register a probe this is called after all other probes
1898         * to only keep ignore_pid set if next pid matches.
1899         */
1900        register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1901                                         tr, INT_MAX);
1902        register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1903                                         tr, 0);
1904
1905        register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1906                                         tr, INT_MAX);
1907        register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1908                                         tr, 0);
1909
1910        register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1911                                             tr, INT_MAX);
1912        register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1913                                             tr, 0);
1914
1915        register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1916                                         tr, INT_MAX);
1917        register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1918                                         tr, 0);
1919}
1920
1921static ssize_t
1922event_pid_write(struct file *filp, const char __user *ubuf,
1923                size_t cnt, loff_t *ppos, int type)
1924{
1925        struct seq_file *m = filp->private_data;
1926        struct trace_array *tr = m->private;
1927        struct trace_pid_list *filtered_pids = NULL;
1928        struct trace_pid_list *other_pids = NULL;
1929        struct trace_pid_list *pid_list;
1930        struct trace_event_file *file;
1931        ssize_t ret;
1932
1933        if (!cnt)
1934                return 0;
1935
1936        ret = tracing_update_buffers();
1937        if (ret < 0)
1938                return ret;
1939
1940        mutex_lock(&event_mutex);
1941
1942        if (type == TRACE_PIDS) {
1943                filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1944                                                          lockdep_is_held(&event_mutex));
1945                other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1946                                                          lockdep_is_held(&event_mutex));
1947        } else {
1948                filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1949                                                          lockdep_is_held(&event_mutex));
1950                other_pids = rcu_dereference_protected(tr->filtered_pids,
1951                                                          lockdep_is_held(&event_mutex));
1952        }
1953
1954        ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1955        if (ret < 0)
1956                goto out;
1957
1958        if (type == TRACE_PIDS)
1959                rcu_assign_pointer(tr->filtered_pids, pid_list);
1960        else
1961                rcu_assign_pointer(tr->filtered_no_pids, pid_list);
1962
1963        list_for_each_entry(file, &tr->events, list) {
1964                set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1965        }
1966
1967        if (filtered_pids) {
1968                tracepoint_synchronize_unregister();
1969                trace_free_pid_list(filtered_pids);
1970        } else if (pid_list && !other_pids) {
1971                register_pid_events(tr);
1972        }
1973
1974        /*
1975         * Ignoring of pids is done at task switch. But we have to
1976         * check for those tasks that are currently running.
1977         * Always do this in case a pid was appended or removed.
1978         */
1979        on_each_cpu(ignore_task_cpu, tr, 1);
1980
1981 out:
1982        mutex_unlock(&event_mutex);
1983
1984        if (ret > 0)
1985                *ppos += ret;
1986
1987        return ret;
1988}
1989
1990static ssize_t
1991ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1992                       size_t cnt, loff_t *ppos)
1993{
1994        return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
1995}
1996
1997static ssize_t
1998ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
1999                        size_t cnt, loff_t *ppos)
2000{
2001        return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2002}
2003
2004static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2005static int ftrace_event_set_open(struct inode *inode, struct file *file);
2006static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2007static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2008static int ftrace_event_release(struct inode *inode, struct file *file);
2009
2010static const struct seq_operations show_event_seq_ops = {
2011        .start = t_start,
2012        .next = t_next,
2013        .show = t_show,
2014        .stop = t_stop,
2015};
2016
2017static const struct seq_operations show_set_event_seq_ops = {
2018        .start = s_start,
2019        .next = s_next,
2020        .show = t_show,
2021        .stop = t_stop,
2022};
2023
2024static const struct seq_operations show_set_pid_seq_ops = {
2025        .start = p_start,
2026        .next = p_next,
2027        .show = trace_pid_show,
2028        .stop = p_stop,
2029};
2030
2031static const struct seq_operations show_set_no_pid_seq_ops = {
2032        .start = np_start,
2033        .next = np_next,
2034        .show = trace_pid_show,
2035        .stop = p_stop,
2036};
2037
2038static const struct file_operations ftrace_avail_fops = {
2039        .open = ftrace_event_avail_open,
2040        .read = seq_read,
2041        .llseek = seq_lseek,
2042        .release = seq_release,
2043};
2044
2045static const struct file_operations ftrace_set_event_fops = {
2046        .open = ftrace_event_set_open,
2047        .read = seq_read,
2048        .write = ftrace_event_write,
2049        .llseek = seq_lseek,
2050        .release = ftrace_event_release,
2051};
2052
2053static const struct file_operations ftrace_set_event_pid_fops = {
2054        .open = ftrace_event_set_pid_open,
2055        .read = seq_read,
2056        .write = ftrace_event_pid_write,
2057        .llseek = seq_lseek,
2058        .release = ftrace_event_release,
2059};
2060
2061static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2062        .open = ftrace_event_set_npid_open,
2063        .read = seq_read,
2064        .write = ftrace_event_npid_write,
2065        .llseek = seq_lseek,
2066        .release = ftrace_event_release,
2067};
2068
2069static const struct file_operations ftrace_enable_fops = {
2070        .open = tracing_open_generic,
2071        .read = event_enable_read,
2072        .write = event_enable_write,
2073        .llseek = default_llseek,
2074};
2075
2076static const struct file_operations ftrace_event_format_fops = {
2077        .open = trace_format_open,
2078        .read = seq_read,
2079        .llseek = seq_lseek,
2080        .release = seq_release,
2081};
2082
2083static const struct file_operations ftrace_event_id_fops = {
2084        .read = event_id_read,
2085        .llseek = default_llseek,
2086};
2087
2088static const struct file_operations ftrace_event_filter_fops = {
2089        .open = tracing_open_generic,
2090        .read = event_filter_read,
2091        .write = event_filter_write,
2092        .llseek = default_llseek,
2093};
2094
2095static const struct file_operations ftrace_subsystem_filter_fops = {
2096        .open = subsystem_open,
2097        .read = subsystem_filter_read,
2098        .write = subsystem_filter_write,
2099        .llseek = default_llseek,
2100        .release = subsystem_release,
2101};
2102
2103static const struct file_operations ftrace_system_enable_fops = {
2104        .open = subsystem_open,
2105        .read = system_enable_read,
2106        .write = system_enable_write,
2107        .llseek = default_llseek,
2108        .release = subsystem_release,
2109};
2110
2111static const struct file_operations ftrace_tr_enable_fops = {
2112        .open = system_tr_open,
2113        .read = system_enable_read,
2114        .write = system_enable_write,
2115        .llseek = default_llseek,
2116        .release = subsystem_release,
2117};
2118
2119static const struct file_operations ftrace_show_header_fops = {
2120        .open = tracing_open_generic,
2121        .read = show_header,
2122        .llseek = default_llseek,
2123};
2124
2125static int
2126ftrace_event_open(struct inode *inode, struct file *file,
2127                  const struct seq_operations *seq_ops)
2128{
2129        struct seq_file *m;
2130        int ret;
2131
2132        ret = security_locked_down(LOCKDOWN_TRACEFS);
2133        if (ret)
2134                return ret;
2135
2136        ret = seq_open(file, seq_ops);
2137        if (ret < 0)
2138                return ret;
2139        m = file->private_data;
2140        /* copy tr over to seq ops */
2141        m->private = inode->i_private;
2142
2143        return ret;
2144}
2145
2146static int ftrace_event_release(struct inode *inode, struct file *file)
2147{
2148        struct trace_array *tr = inode->i_private;
2149
2150        trace_array_put(tr);
2151
2152        return seq_release(inode, file);
2153}
2154
2155static int
2156ftrace_event_avail_open(struct inode *inode, struct file *file)
2157{
2158        const struct seq_operations *seq_ops = &show_event_seq_ops;
2159
2160        /* Checks for tracefs lockdown */
2161        return ftrace_event_open(inode, file, seq_ops);
2162}
2163
2164static int
2165ftrace_event_set_open(struct inode *inode, struct file *file)
2166{
2167        const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2168        struct trace_array *tr = inode->i_private;
2169        int ret;
2170
2171        ret = tracing_check_open_get_tr(tr);
2172        if (ret)
2173                return ret;
2174
2175        if ((file->f_mode & FMODE_WRITE) &&
2176            (file->f_flags & O_TRUNC))
2177                ftrace_clear_events(tr);
2178
2179        ret = ftrace_event_open(inode, file, seq_ops);
2180        if (ret < 0)
2181                trace_array_put(tr);
2182        return ret;
2183}
2184
2185static int
2186ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2187{
2188        const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2189        struct trace_array *tr = inode->i_private;
2190        int ret;
2191
2192        ret = tracing_check_open_get_tr(tr);
2193        if (ret)
2194                return ret;
2195
2196        if ((file->f_mode & FMODE_WRITE) &&
2197            (file->f_flags & O_TRUNC))
2198                ftrace_clear_event_pids(tr, TRACE_PIDS);
2199
2200        ret = ftrace_event_open(inode, file, seq_ops);
2201        if (ret < 0)
2202                trace_array_put(tr);
2203        return ret;
2204}
2205
2206static int
2207ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2208{
2209        const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2210        struct trace_array *tr = inode->i_private;
2211        int ret;
2212
2213        ret = tracing_check_open_get_tr(tr);
2214        if (ret)
2215                return ret;
2216
2217        if ((file->f_mode & FMODE_WRITE) &&
2218            (file->f_flags & O_TRUNC))
2219                ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2220
2221        ret = ftrace_event_open(inode, file, seq_ops);
2222        if (ret < 0)
2223                trace_array_put(tr);
2224        return ret;
2225}
2226
2227static struct event_subsystem *
2228create_new_subsystem(const char *name)
2229{
2230        struct event_subsystem *system;
2231
2232        /* need to create new entry */
2233        system = kmalloc(sizeof(*system), GFP_KERNEL);
2234        if (!system)
2235                return NULL;
2236
2237        system->ref_count = 1;
2238
2239        /* Only allocate if dynamic (kprobes and modules) */
2240        system->name = kstrdup_const(name, GFP_KERNEL);
2241        if (!system->name)
2242                goto out_free;
2243
2244        system->filter = NULL;
2245
2246        system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2247        if (!system->filter)
2248                goto out_free;
2249
2250        list_add(&system->list, &event_subsystems);
2251
2252        return system;
2253
2254 out_free:
2255        kfree_const(system->name);
2256        kfree(system);
2257        return NULL;
2258}
2259
2260static struct dentry *
2261event_subsystem_dir(struct trace_array *tr, const char *name,
2262                    struct trace_event_file *file, struct dentry *parent)
2263{
2264        struct trace_subsystem_dir *dir;
2265        struct event_subsystem *system;
2266        struct dentry *entry;
2267
2268        /* First see if we did not already create this dir */
2269        list_for_each_entry(dir, &tr->systems, list) {
2270                system = dir->subsystem;
2271                if (strcmp(system->name, name) == 0) {
2272                        dir->nr_events++;
2273                        file->system = dir;
2274                        return dir->entry;
2275                }
2276        }
2277
2278        /* Now see if the system itself exists. */
2279        list_for_each_entry(system, &event_subsystems, list) {
2280                if (strcmp(system->name, name) == 0)
2281                        break;
2282        }
2283        /* Reset system variable when not found */
2284        if (&system->list == &event_subsystems)
2285                system = NULL;
2286
2287        dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2288        if (!dir)
2289                goto out_fail;
2290
2291        if (!system) {
2292                system = create_new_subsystem(name);
2293                if (!system)
2294                        goto out_free;
2295        } else
2296                __get_system(system);
2297
2298        dir->entry = tracefs_create_dir(name, parent);
2299        if (!dir->entry) {
2300                pr_warn("Failed to create system directory %s\n", name);
2301                __put_system(system);
2302                goto out_free;
2303        }
2304
2305        dir->tr = tr;
2306        dir->ref_count = 1;
2307        dir->nr_events = 1;
2308        dir->subsystem = system;
2309        file->system = dir;
2310
2311        /* the ftrace system is special, do not create enable or filter files */
2312        if (strcmp(name, "ftrace") != 0) {
2313
2314                entry = tracefs_create_file("filter", 0644, dir->entry, dir,
2315                                            &ftrace_subsystem_filter_fops);
2316                if (!entry) {
2317                        kfree(system->filter);
2318                        system->filter = NULL;
2319                        pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2320                }
2321
2322                trace_create_file("enable", 0644, dir->entry, dir,
2323                                  &ftrace_system_enable_fops);
2324        }
2325
2326        list_add(&dir->list, &tr->systems);
2327
2328        return dir->entry;
2329
2330 out_free:
2331        kfree(dir);
2332 out_fail:
2333        /* Only print this message if failed on memory allocation */
2334        if (!dir || !system)
2335                pr_warn("No memory to create event subsystem %s\n", name);
2336        return NULL;
2337}
2338
2339static int
2340event_define_fields(struct trace_event_call *call)
2341{
2342        struct list_head *head;
2343        int ret = 0;
2344
2345        /*
2346         * Other events may have the same class. Only update
2347         * the fields if they are not already defined.
2348         */
2349        head = trace_get_fields(call);
2350        if (list_empty(head)) {
2351                struct trace_event_fields *field = call->class->fields_array;
2352                unsigned int offset = sizeof(struct trace_entry);
2353
2354                for (; field->type; field++) {
2355                        if (field->type == TRACE_FUNCTION_TYPE) {
2356                                field->define_fields(call);
2357                                break;
2358                        }
2359
2360                        offset = ALIGN(offset, field->align);
2361                        ret = trace_define_field(call, field->type, field->name,
2362                                                 offset, field->size,
2363                                                 field->is_signed, field->filter_type);
2364                        if (WARN_ON_ONCE(ret)) {
2365                                pr_err("error code is %d\n", ret);
2366                                break;
2367                        }
2368
2369                        offset += field->size;
2370                }
2371        }
2372
2373        return ret;
2374}
2375
2376static int
2377event_create_dir(struct dentry *parent, struct trace_event_file *file)
2378{
2379        struct trace_event_call *call = file->event_call;
2380        struct trace_array *tr = file->tr;
2381        struct dentry *d_events;
2382        const char *name;
2383        int ret;
2384
2385        /*
2386         * If the trace point header did not define TRACE_SYSTEM
2387         * then the system would be called "TRACE_SYSTEM".
2388         */
2389        if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2390                d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2391                if (!d_events)
2392                        return -ENOMEM;
2393        } else
2394                d_events = parent;
2395
2396        name = trace_event_name(call);
2397        file->dir = tracefs_create_dir(name, d_events);
2398        if (!file->dir) {
2399                pr_warn("Could not create tracefs '%s' directory\n", name);
2400                return -1;
2401        }
2402
2403        if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2404                trace_create_file("enable", 0644, file->dir, file,
2405                                  &ftrace_enable_fops);
2406
2407#ifdef CONFIG_PERF_EVENTS
2408        if (call->event.type && call->class->reg)
2409                trace_create_file("id", 0444, file->dir,
2410                                  (void *)(long)call->event.type,
2411                                  &ftrace_event_id_fops);
2412#endif
2413
2414        ret = event_define_fields(call);
2415        if (ret < 0) {
2416                pr_warn("Could not initialize trace point events/%s\n", name);
2417                return ret;
2418        }
2419
2420        /*
2421         * Only event directories that can be enabled should have
2422         * triggers or filters.
2423         */
2424        if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2425                trace_create_file("filter", 0644, file->dir, file,
2426                                  &ftrace_event_filter_fops);
2427
2428                trace_create_file("trigger", 0644, file->dir, file,
2429                                  &event_trigger_fops);
2430        }
2431
2432#ifdef CONFIG_HIST_TRIGGERS
2433        trace_create_file("hist", 0444, file->dir, file,
2434                          &event_hist_fops);
2435#endif
2436#ifdef CONFIG_HIST_TRIGGERS_DEBUG
2437        trace_create_file("hist_debug", 0444, file->dir, file,
2438                          &event_hist_debug_fops);
2439#endif
2440        trace_create_file("format", 0444, file->dir, call,
2441                          &ftrace_event_format_fops);
2442
2443#ifdef CONFIG_TRACE_EVENT_INJECT
2444        if (call->event.type && call->class->reg)
2445                trace_create_file("inject", 0200, file->dir, file,
2446                                  &event_inject_fops);
2447#endif
2448
2449        return 0;
2450}
2451
2452static void remove_event_from_tracers(struct trace_event_call *call)
2453{
2454        struct trace_event_file *file;
2455        struct trace_array *tr;
2456
2457        do_for_each_event_file_safe(tr, file) {
2458                if (file->event_call != call)
2459                        continue;
2460
2461                remove_event_file_dir(file);
2462                /*
2463                 * The do_for_each_event_file_safe() is
2464                 * a double loop. After finding the call for this
2465                 * trace_array, we use break to jump to the next
2466                 * trace_array.
2467                 */
2468                break;
2469        } while_for_each_event_file();
2470}
2471
2472static void event_remove(struct trace_event_call *call)
2473{
2474        struct trace_array *tr;
2475        struct trace_event_file *file;
2476
2477        do_for_each_event_file(tr, file) {
2478                if (file->event_call != call)
2479                        continue;
2480
2481                if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2482                        tr->clear_trace = true;
2483
2484                ftrace_event_enable_disable(file, 0);
2485                /*
2486                 * The do_for_each_event_file() is
2487                 * a double loop. After finding the call for this
2488                 * trace_array, we use break to jump to the next
2489                 * trace_array.
2490                 */
2491                break;
2492        } while_for_each_event_file();
2493
2494        if (call->event.funcs)
2495                __unregister_trace_event(&call->event);
2496        remove_event_from_tracers(call);
2497        list_del(&call->list);
2498}
2499
2500static int event_init(struct trace_event_call *call)
2501{
2502        int ret = 0;
2503        const char *name;
2504
2505        name = trace_event_name(call);
2506        if (WARN_ON(!name))
2507                return -EINVAL;
2508
2509        if (call->class->raw_init) {
2510                ret = call->class->raw_init(call);
2511                if (ret < 0 && ret != -ENOSYS)
2512                        pr_warn("Could not initialize trace events/%s\n", name);
2513        }
2514
2515        return ret;
2516}
2517
2518static int
2519__register_event(struct trace_event_call *call, struct module *mod)
2520{
2521        int ret;
2522
2523        ret = event_init(call);
2524        if (ret < 0)
2525                return ret;
2526
2527        list_add(&call->list, &ftrace_events);
2528        call->mod = mod;
2529
2530        return 0;
2531}
2532
2533static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2534{
2535        int rlen;
2536        int elen;
2537
2538        /* Find the length of the eval value as a string */
2539        elen = snprintf(ptr, 0, "%ld", map->eval_value);
2540        /* Make sure there's enough room to replace the string with the value */
2541        if (len < elen)
2542                return NULL;
2543
2544        snprintf(ptr, elen + 1, "%ld", map->eval_value);
2545
2546        /* Get the rest of the string of ptr */
2547        rlen = strlen(ptr + len);
2548        memmove(ptr + elen, ptr + len, rlen);
2549        /* Make sure we end the new string */
2550        ptr[elen + rlen] = 0;
2551
2552        return ptr + elen;
2553}
2554
2555static void update_event_printk(struct trace_event_call *call,
2556                                struct trace_eval_map *map)
2557{
2558        char *ptr;
2559        int quote = 0;
2560        int len = strlen(map->eval_string);
2561
2562        for (ptr = call->print_fmt; *ptr; ptr++) {
2563                if (*ptr == '\\') {
2564                        ptr++;
2565                        /* paranoid */
2566                        if (!*ptr)
2567                                break;
2568                        continue;
2569                }
2570                if (*ptr == '"') {
2571                        quote ^= 1;
2572                        continue;
2573                }
2574                if (quote)
2575                        continue;
2576                if (isdigit(*ptr)) {
2577                        /* skip numbers */
2578                        do {
2579                                ptr++;
2580                                /* Check for alpha chars like ULL */
2581                        } while (isalnum(*ptr));
2582                        if (!*ptr)
2583                                break;
2584                        /*
2585                         * A number must have some kind of delimiter after
2586                         * it, and we can ignore that too.
2587                         */
2588                        continue;
2589                }
2590                if (isalpha(*ptr) || *ptr == '_') {
2591                        if (strncmp(map->eval_string, ptr, len) == 0 &&
2592                            !isalnum(ptr[len]) && ptr[len] != '_') {
2593                                ptr = eval_replace(ptr, map, len);
2594                                /* enum/sizeof string smaller than value */
2595                                if (WARN_ON_ONCE(!ptr))
2596                                        return;
2597                                /*
2598                                 * No need to decrement here, as eval_replace()
2599                                 * returns the pointer to the character passed
2600                                 * the eval, and two evals can not be placed
2601                                 * back to back without something in between.
2602                                 * We can skip that something in between.
2603                                 */
2604                                continue;
2605                        }
2606                skip_more:
2607                        do {
2608                                ptr++;
2609                        } while (isalnum(*ptr) || *ptr == '_');
2610                        if (!*ptr)
2611                                break;
2612                        /*
2613                         * If what comes after this variable is a '.' or
2614                         * '->' then we can continue to ignore that string.
2615                         */
2616                        if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2617                                ptr += *ptr == '.' ? 1 : 2;
2618                                if (!*ptr)
2619                                        break;
2620                                goto skip_more;
2621                        }
2622                        /*
2623                         * Once again, we can skip the delimiter that came
2624                         * after the string.
2625                         */
2626                        continue;
2627                }
2628        }
2629}
2630
2631void trace_event_eval_update(struct trace_eval_map **map, int len)
2632{
2633        struct trace_event_call *call, *p;
2634        const char *last_system = NULL;
2635        bool first = false;
2636        int last_i;
2637        int i;
2638
2639        down_write(&trace_event_sem);
2640        list_for_each_entry_safe(call, p, &ftrace_events, list) {
2641                /* events are usually grouped together with systems */
2642                if (!last_system || call->class->system != last_system) {
2643                        first = true;
2644                        last_i = 0;
2645                        last_system = call->class->system;
2646                }
2647
2648                /*
2649                 * Since calls are grouped by systems, the likelihood that the
2650                 * next call in the iteration belongs to the same system as the
2651                 * previous call is high. As an optimization, we skip searching
2652                 * for a map[] that matches the call's system if the last call
2653                 * was from the same system. That's what last_i is for. If the
2654                 * call has the same system as the previous call, then last_i
2655                 * will be the index of the first map[] that has a matching
2656                 * system.
2657                 */
2658                for (i = last_i; i < len; i++) {
2659                        if (call->class->system == map[i]->system) {
2660                                /* Save the first system if need be */
2661                                if (first) {
2662                                        last_i = i;
2663                                        first = false;
2664                                }
2665                                update_event_printk(call, map[i]);
2666                        }
2667                }
2668        }
2669        up_write(&trace_event_sem);
2670}
2671
2672static struct trace_event_file *
2673trace_create_new_event(struct trace_event_call *call,
2674                       struct trace_array *tr)
2675{
2676        struct trace_event_file *file;
2677
2678        file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2679        if (!file)
2680                return NULL;
2681
2682        file->event_call = call;
2683        file->tr = tr;
2684        atomic_set(&file->sm_ref, 0);
2685        atomic_set(&file->tm_ref, 0);
2686        INIT_LIST_HEAD(&file->triggers);
2687        list_add(&file->list, &tr->events);
2688
2689        return file;
2690}
2691
2692/* Add an event to a trace directory */
2693static int
2694__trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2695{
2696        struct trace_event_file *file;
2697
2698        file = trace_create_new_event(call, tr);
2699        if (!file)
2700                return -ENOMEM;
2701
2702        if (eventdir_initialized)
2703                return event_create_dir(tr->event_dir, file);
2704        else
2705                return event_define_fields(call);
2706}
2707
2708/*
2709 * Just create a descriptor for early init. A descriptor is required
2710 * for enabling events at boot. We want to enable events before
2711 * the filesystem is initialized.
2712 */
2713static int
2714__trace_early_add_new_event(struct trace_event_call *call,
2715                            struct trace_array *tr)
2716{
2717        struct trace_event_file *file;
2718
2719        file = trace_create_new_event(call, tr);
2720        if (!file)
2721                return -ENOMEM;
2722
2723        return event_define_fields(call);
2724}
2725
2726struct ftrace_module_file_ops;
2727static void __add_event_to_tracers(struct trace_event_call *call);
2728
2729/* Add an additional event_call dynamically */
2730int trace_add_event_call(struct trace_event_call *call)
2731{
2732        int ret;
2733        lockdep_assert_held(&event_mutex);
2734
2735        mutex_lock(&trace_types_lock);
2736
2737        ret = __register_event(call, NULL);
2738        if (ret >= 0)
2739                __add_event_to_tracers(call);
2740
2741        mutex_unlock(&trace_types_lock);
2742        return ret;
2743}
2744
2745/*
2746 * Must be called under locking of trace_types_lock, event_mutex and
2747 * trace_event_sem.
2748 */
2749static void __trace_remove_event_call(struct trace_event_call *call)
2750{
2751        event_remove(call);
2752        trace_destroy_fields(call);
2753        free_event_filter(call->filter);
2754        call->filter = NULL;
2755}
2756
2757static int probe_remove_event_call(struct trace_event_call *call)
2758{
2759        struct trace_array *tr;
2760        struct trace_event_file *file;
2761
2762#ifdef CONFIG_PERF_EVENTS
2763        if (call->perf_refcount)
2764                return -EBUSY;
2765#endif
2766        do_for_each_event_file(tr, file) {
2767                if (file->event_call != call)
2768                        continue;
2769                /*
2770                 * We can't rely on ftrace_event_enable_disable(enable => 0)
2771                 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2772                 * TRACE_REG_UNREGISTER.
2773                 */
2774                if (file->flags & EVENT_FILE_FL_ENABLED)
2775                        return -EBUSY;
2776                /*
2777                 * The do_for_each_event_file_safe() is
2778                 * a double loop. After finding the call for this
2779                 * trace_array, we use break to jump to the next
2780                 * trace_array.
2781                 */
2782                break;
2783        } while_for_each_event_file();
2784
2785        __trace_remove_event_call(call);
2786
2787        return 0;
2788}
2789
2790/* Remove an event_call */
2791int trace_remove_event_call(struct trace_event_call *call)
2792{
2793        int ret;
2794
2795        lockdep_assert_held(&event_mutex);
2796
2797        mutex_lock(&trace_types_lock);
2798        down_write(&trace_event_sem);
2799        ret = probe_remove_event_call(call);
2800        up_write(&trace_event_sem);
2801        mutex_unlock(&trace_types_lock);
2802
2803        return ret;
2804}
2805
2806#define for_each_event(event, start, end)                       \
2807        for (event = start;                                     \
2808             (unsigned long)event < (unsigned long)end;         \
2809             event++)
2810
2811#ifdef CONFIG_MODULES
2812
2813static void trace_module_add_events(struct module *mod)
2814{
2815        struct trace_event_call **call, **start, **end;
2816
2817        if (!mod->num_trace_events)
2818                return;
2819
2820        /* Don't add infrastructure for mods without tracepoints */
2821        if (trace_module_has_bad_taint(mod)) {
2822                pr_err("%s: module has bad taint, not creating trace events\n",
2823                       mod->name);
2824                return;
2825        }
2826
2827        start = mod->trace_events;
2828        end = mod->trace_events + mod->num_trace_events;
2829
2830        for_each_event(call, start, end) {
2831                __register_event(*call, mod);
2832                __add_event_to_tracers(*call);
2833        }
2834}
2835
2836static void trace_module_remove_events(struct module *mod)
2837{
2838        struct trace_event_call *call, *p;
2839
2840        down_write(&trace_event_sem);
2841        list_for_each_entry_safe(call, p, &ftrace_events, list) {
2842                if (call->mod == mod)
2843                        __trace_remove_event_call(call);
2844        }
2845        up_write(&trace_event_sem);
2846
2847        /*
2848         * It is safest to reset the ring buffer if the module being unloaded
2849         * registered any events that were used. The only worry is if
2850         * a new module gets loaded, and takes on the same id as the events
2851         * of this module. When printing out the buffer, traced events left
2852         * over from this module may be passed to the new module events and
2853         * unexpected results may occur.
2854         */
2855        tracing_reset_all_online_cpus();
2856}
2857
2858static int trace_module_notify(struct notifier_block *self,
2859                               unsigned long val, void *data)
2860{
2861        struct module *mod = data;
2862
2863        mutex_lock(&event_mutex);
2864        mutex_lock(&trace_types_lock);
2865        switch (val) {
2866        case MODULE_STATE_COMING:
2867                trace_module_add_events(mod);
2868                break;
2869        case MODULE_STATE_GOING:
2870                trace_module_remove_events(mod);
2871                break;
2872        }
2873        mutex_unlock(&trace_types_lock);
2874        mutex_unlock(&event_mutex);
2875
2876        return NOTIFY_OK;
2877}
2878
2879static struct notifier_block trace_module_nb = {
2880        .notifier_call = trace_module_notify,
2881        .priority = 1, /* higher than trace.c module notify */
2882};
2883#endif /* CONFIG_MODULES */
2884
2885/* Create a new event directory structure for a trace directory. */
2886static void
2887__trace_add_event_dirs(struct trace_array *tr)
2888{
2889        struct trace_event_call *call;
2890        int ret;
2891
2892        list_for_each_entry(call, &ftrace_events, list) {
2893                ret = __trace_add_new_event(call, tr);
2894                if (ret < 0)
2895                        pr_warn("Could not create directory for event %s\n",
2896                                trace_event_name(call));
2897        }
2898}
2899
2900/* Returns any file that matches the system and event */
2901struct trace_event_file *
2902__find_event_file(struct trace_array *tr, const char *system, const char *event)
2903{
2904        struct trace_event_file *file;
2905        struct trace_event_call *call;
2906        const char *name;
2907
2908        list_for_each_entry(file, &tr->events, list) {
2909
2910                call = file->event_call;
2911                name = trace_event_name(call);
2912
2913                if (!name || !call->class)
2914                        continue;
2915
2916                if (strcmp(event, name) == 0 &&
2917                    strcmp(system, call->class->system) == 0)
2918                        return file;
2919        }
2920        return NULL;
2921}
2922
2923/* Returns valid trace event files that match system and event */
2924struct trace_event_file *
2925find_event_file(struct trace_array *tr, const char *system, const char *event)
2926{
2927        struct trace_event_file *file;
2928
2929        file = __find_event_file(tr, system, event);
2930        if (!file || !file->event_call->class->reg ||
2931            file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2932                return NULL;
2933
2934        return file;
2935}
2936
2937/**
2938 * trace_get_event_file - Find and return a trace event file
2939 * @instance: The name of the trace instance containing the event
2940 * @system: The name of the system containing the event
2941 * @event: The name of the event
2942 *
2943 * Return a trace event file given the trace instance name, trace
2944 * system, and trace event name.  If the instance name is NULL, it
2945 * refers to the top-level trace array.
2946 *
2947 * This function will look it up and return it if found, after calling
2948 * trace_array_get() to prevent the instance from going away, and
2949 * increment the event's module refcount to prevent it from being
2950 * removed.
2951 *
2952 * To release the file, call trace_put_event_file(), which will call
2953 * trace_array_put() and decrement the event's module refcount.
2954 *
2955 * Return: The trace event on success, ERR_PTR otherwise.
2956 */
2957struct trace_event_file *trace_get_event_file(const char *instance,
2958                                              const char *system,
2959                                              const char *event)
2960{
2961        struct trace_array *tr = top_trace_array();
2962        struct trace_event_file *file = NULL;
2963        int ret = -EINVAL;
2964
2965        if (instance) {
2966                tr = trace_array_find_get(instance);
2967                if (!tr)
2968                        return ERR_PTR(-ENOENT);
2969        } else {
2970                ret = trace_array_get(tr);
2971                if (ret)
2972                        return ERR_PTR(ret);
2973        }
2974
2975        mutex_lock(&event_mutex);
2976
2977        file = find_event_file(tr, system, event);
2978        if (!file) {
2979                trace_array_put(tr);
2980                ret = -EINVAL;
2981                goto out;
2982        }
2983
2984        /* Don't let event modules unload while in use */
2985        ret = try_module_get(file->event_call->mod);
2986        if (!ret) {
2987                trace_array_put(tr);
2988                ret = -EBUSY;
2989                goto out;
2990        }
2991
2992        ret = 0;
2993 out:
2994        mutex_unlock(&event_mutex);
2995
2996        if (ret)
2997                file = ERR_PTR(ret);
2998
2999        return file;
3000}
3001EXPORT_SYMBOL_GPL(trace_get_event_file);
3002
3003/**
3004 * trace_put_event_file - Release a file from trace_get_event_file()
3005 * @file: The trace event file
3006 *
3007 * If a file was retrieved using trace_get_event_file(), this should
3008 * be called when it's no longer needed.  It will cancel the previous
3009 * trace_array_get() called by that function, and decrement the
3010 * event's module refcount.
3011 */
3012void trace_put_event_file(struct trace_event_file *file)
3013{
3014        mutex_lock(&event_mutex);
3015        module_put(file->event_call->mod);
3016        mutex_unlock(&event_mutex);
3017
3018        trace_array_put(file->tr);
3019}
3020EXPORT_SYMBOL_GPL(trace_put_event_file);
3021
3022#ifdef CONFIG_DYNAMIC_FTRACE
3023
3024/* Avoid typos */
3025#define ENABLE_EVENT_STR        "enable_event"
3026#define DISABLE_EVENT_STR       "disable_event"
3027
3028struct event_probe_data {
3029        struct trace_event_file *file;
3030        unsigned long                   count;
3031        int                             ref;
3032        bool                            enable;
3033};
3034
3035static void update_event_probe(struct event_probe_data *data)
3036{
3037        if (data->enable)
3038                clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3039        else
3040                set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3041}
3042
3043static void
3044event_enable_probe(unsigned long ip, unsigned long parent_ip,
3045                   struct trace_array *tr, struct ftrace_probe_ops *ops,
3046                   void *data)
3047{
3048        struct ftrace_func_mapper *mapper = data;
3049        struct event_probe_data *edata;
3050        void **pdata;
3051
3052        pdata = ftrace_func_mapper_find_ip(mapper, ip);
3053        if (!pdata || !*pdata)
3054                return;
3055
3056        edata = *pdata;
3057        update_event_probe(edata);
3058}
3059
3060static void
3061event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3062                         struct trace_array *tr, struct ftrace_probe_ops *ops,
3063                         void *data)
3064{
3065        struct ftrace_func_mapper *mapper = data;
3066        struct event_probe_data *edata;
3067        void **pdata;
3068
3069        pdata = ftrace_func_mapper_find_ip(mapper, ip);
3070        if (!pdata || !*pdata)
3071                return;
3072
3073        edata = *pdata;
3074
3075        if (!edata->count)
3076                return;
3077
3078        /* Skip if the event is in a state we want to switch to */
3079        if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3080                return;
3081
3082        if (edata->count != -1)
3083                (edata->count)--;
3084
3085        update_event_probe(edata);
3086}
3087
3088static int
3089event_enable_print(struct seq_file *m, unsigned long ip,
3090                   struct ftrace_probe_ops *ops, void *data)
3091{
3092        struct ftrace_func_mapper *mapper = data;
3093        struct event_probe_data *edata;
3094        void **pdata;
3095
3096        pdata = ftrace_func_mapper_find_ip(mapper, ip);
3097
3098        if (WARN_ON_ONCE(!pdata || !*pdata))
3099                return 0;
3100
3101        edata = *pdata;
3102
3103        seq_printf(m, "%ps:", (void *)ip);
3104
3105        seq_printf(m, "%s:%s:%s",
3106                   edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3107                   edata->file->event_call->class->system,
3108                   trace_event_name(edata->file->event_call));
3109
3110        if (edata->count == -1)
3111                seq_puts(m, ":unlimited\n");
3112        else
3113                seq_printf(m, ":count=%ld\n", edata->count);
3114
3115        return 0;
3116}
3117
3118static int
3119event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3120                  unsigned long ip, void *init_data, void **data)
3121{
3122        struct ftrace_func_mapper *mapper = *data;
3123        struct event_probe_data *edata = init_data;
3124        int ret;
3125
3126        if (!mapper) {
3127                mapper = allocate_ftrace_func_mapper();
3128                if (!mapper)
3129                        return -ENODEV;
3130                *data = mapper;
3131        }
3132
3133        ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3134        if (ret < 0)
3135                return ret;
3136
3137        edata->ref++;
3138
3139        return 0;
3140}
3141
3142static int free_probe_data(void *data)
3143{
3144        struct event_probe_data *edata = data;
3145
3146        edata->ref--;
3147        if (!edata->ref) {
3148                /* Remove the SOFT_MODE flag */
3149                __ftrace_event_enable_disable(edata->file, 0, 1);
3150                module_put(edata->file->event_call->mod);
3151                kfree(edata);
3152        }
3153        return 0;
3154}
3155
3156static void
3157event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3158                  unsigned long ip, void *data)
3159{
3160        struct ftrace_func_mapper *mapper = data;
3161        struct event_probe_data *edata;
3162
3163        if (!ip) {
3164                if (!mapper)
3165                        return;
3166                free_ftrace_func_mapper(mapper, free_probe_data);
3167                return;
3168        }
3169
3170        edata = ftrace_func_mapper_remove_ip(mapper, ip);
3171
3172        if (WARN_ON_ONCE(!edata))
3173                return;
3174
3175        if (WARN_ON_ONCE(edata->ref <= 0))
3176                return;
3177
3178        free_probe_data(edata);
3179}
3180
3181static struct ftrace_probe_ops event_enable_probe_ops = {
3182        .func                   = event_enable_probe,
3183        .print                  = event_enable_print,
3184        .init                   = event_enable_init,
3185        .free                   = event_enable_free,
3186};
3187
3188static struct ftrace_probe_ops event_enable_count_probe_ops = {
3189        .func                   = event_enable_count_probe,
3190        .print                  = event_enable_print,
3191        .init                   = event_enable_init,
3192        .free                   = event_enable_free,
3193};
3194
3195static struct ftrace_probe_ops event_disable_probe_ops = {
3196        .func                   = event_enable_probe,
3197        .print                  = event_enable_print,
3198        .init                   = event_enable_init,
3199        .free                   = event_enable_free,
3200};
3201
3202static struct ftrace_probe_ops event_disable_count_probe_ops = {
3203        .func                   = event_enable_count_probe,
3204        .print                  = event_enable_print,
3205        .init                   = event_enable_init,
3206        .free                   = event_enable_free,
3207};
3208
3209static int
3210event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3211                  char *glob, char *cmd, char *param, int enabled)
3212{
3213        struct trace_event_file *file;
3214        struct ftrace_probe_ops *ops;
3215        struct event_probe_data *data;
3216        const char *system;
3217        const char *event;
3218        char *number;
3219        bool enable;
3220        int ret;
3221
3222        if (!tr)
3223                return -ENODEV;
3224
3225        /* hash funcs only work with set_ftrace_filter */
3226        if (!enabled || !param)
3227                return -EINVAL;
3228
3229        system = strsep(&param, ":");
3230        if (!param)
3231                return -EINVAL;
3232
3233        event = strsep(&param, ":");
3234
3235        mutex_lock(&event_mutex);
3236
3237        ret = -EINVAL;
3238        file = find_event_file(tr, system, event);
3239        if (!file)
3240                goto out;
3241
3242        enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3243
3244        if (enable)
3245                ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3246        else
3247                ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3248
3249        if (glob[0] == '!') {
3250                ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3251                goto out;
3252        }
3253
3254        ret = -ENOMEM;
3255
3256        data = kzalloc(sizeof(*data), GFP_KERNEL);
3257        if (!data)
3258                goto out;
3259
3260        data->enable = enable;
3261        data->count = -1;
3262        data->file = file;
3263
3264        if (!param)
3265                goto out_reg;
3266
3267        number = strsep(&param, ":");
3268
3269        ret = -EINVAL;
3270        if (!strlen(number))
3271                goto out_free;
3272
3273        /*
3274         * We use the callback data field (which is a pointer)
3275         * as our counter.
3276         */
3277        ret = kstrtoul(number, 0, &data->count);
3278        if (ret)
3279                goto out_free;
3280
3281 out_reg:
3282        /* Don't let event modules unload while probe registered */
3283        ret = try_module_get(file->event_call->mod);
3284        if (!ret) {
3285                ret = -EBUSY;
3286                goto out_free;
3287        }
3288
3289        ret = __ftrace_event_enable_disable(file, 1, 1);
3290        if (ret < 0)
3291                goto out_put;
3292
3293        ret = register_ftrace_function_probe(glob, tr, ops, data);
3294        /*
3295         * The above returns on success the # of functions enabled,
3296         * but if it didn't find any functions it returns zero.
3297         * Consider no functions a failure too.
3298         */
3299        if (!ret) {
3300                ret = -ENOENT;
3301                goto out_disable;
3302        } else if (ret < 0)
3303                goto out_disable;
3304        /* Just return zero, not the number of enabled functions */
3305        ret = 0;
3306 out:
3307        mutex_unlock(&event_mutex);
3308        return ret;
3309
3310 out_disable:
3311        __ftrace_event_enable_disable(file, 0, 1);
3312 out_put:
3313        module_put(file->event_call->mod);
3314 out_free:
3315        kfree(data);
3316        goto out;
3317}
3318
3319static struct ftrace_func_command event_enable_cmd = {
3320        .name                   = ENABLE_EVENT_STR,
3321        .func                   = event_enable_func,
3322};
3323
3324static struct ftrace_func_command event_disable_cmd = {
3325        .name                   = DISABLE_EVENT_STR,
3326        .func                   = event_enable_func,
3327};
3328
3329static __init int register_event_cmds(void)
3330{
3331        int ret;
3332
3333        ret = register_ftrace_command(&event_enable_cmd);
3334        if (WARN_ON(ret < 0))
3335                return ret;
3336        ret = register_ftrace_command(&event_disable_cmd);
3337        if (WARN_ON(ret < 0))
3338                unregister_ftrace_command(&event_enable_cmd);
3339        return ret;
3340}
3341#else
3342static inline int register_event_cmds(void) { return 0; }
3343#endif /* CONFIG_DYNAMIC_FTRACE */
3344
3345/*
3346 * The top level array and trace arrays created by boot-time tracing
3347 * have already had its trace_event_file descriptors created in order
3348 * to allow for early events to be recorded.
3349 * This function is called after the tracefs has been initialized,
3350 * and we now have to create the files associated to the events.
3351 */
3352static void __trace_early_add_event_dirs(struct trace_array *tr)
3353{
3354        struct trace_event_file *file;
3355        int ret;
3356
3357
3358        list_for_each_entry(file, &tr->events, list) {
3359                ret = event_create_dir(tr->event_dir, file);
3360                if (ret < 0)
3361                        pr_warn("Could not create directory for event %s\n",
3362                                trace_event_name(file->event_call));
3363        }
3364}
3365
3366/*
3367 * For early boot up, the top trace array and the trace arrays created
3368 * by boot-time tracing require to have a list of events that can be
3369 * enabled. This must be done before the filesystem is set up in order
3370 * to allow events to be traced early.
3371 */
3372void __trace_early_add_events(struct trace_array *tr)
3373{
3374        struct trace_event_call *call;
3375        int ret;
3376
3377        list_for_each_entry(call, &ftrace_events, list) {
3378                /* Early boot up should not have any modules loaded */
3379                if (WARN_ON_ONCE(call->mod))
3380                        continue;
3381
3382                ret = __trace_early_add_new_event(call, tr);
3383                if (ret < 0)
3384                        pr_warn("Could not create early event %s\n",
3385                                trace_event_name(call));
3386        }
3387}
3388
3389/* Remove the event directory structure for a trace directory. */
3390static void
3391__trace_remove_event_dirs(struct trace_array *tr)
3392{
3393        struct trace_event_file *file, *next;
3394
3395        list_for_each_entry_safe(file, next, &tr->events, list)
3396                remove_event_file_dir(file);
3397}
3398
3399static void __add_event_to_tracers(struct trace_event_call *call)
3400{
3401        struct trace_array *tr;
3402
3403        list_for_each_entry(tr, &ftrace_trace_arrays, list)
3404                __trace_add_new_event(call, tr);
3405}
3406
3407extern struct trace_event_call *__start_ftrace_events[];
3408extern struct trace_event_call *__stop_ftrace_events[];
3409
3410static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3411
3412static __init int setup_trace_event(char *str)
3413{
3414        strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3415        ring_buffer_expanded = true;
3416        disable_tracing_selftest("running event tracing");
3417
3418        return 1;
3419}
3420__setup("trace_event=", setup_trace_event);
3421
3422/* Expects to have event_mutex held when called */
3423static int
3424create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3425{
3426        struct dentry *d_events;
3427        struct dentry *entry;
3428
3429        entry = tracefs_create_file("set_event", 0644, parent,
3430                                    tr, &ftrace_set_event_fops);
3431        if (!entry) {
3432                pr_warn("Could not create tracefs 'set_event' entry\n");
3433                return -ENOMEM;
3434        }
3435
3436        d_events = tracefs_create_dir("events", parent);
3437        if (!d_events) {
3438                pr_warn("Could not create tracefs 'events' directory\n");
3439                return -ENOMEM;
3440        }
3441
3442        entry = trace_create_file("enable", 0644, d_events,
3443                                  tr, &ftrace_tr_enable_fops);
3444        if (!entry) {
3445                pr_warn("Could not create tracefs 'enable' entry\n");
3446                return -ENOMEM;
3447        }
3448
3449        /* There are not as crucial, just warn if they are not created */
3450
3451        entry = tracefs_create_file("set_event_pid", 0644, parent,
3452                                    tr, &ftrace_set_event_pid_fops);
3453        if (!entry)
3454                pr_warn("Could not create tracefs 'set_event_pid' entry\n");
3455
3456        entry = tracefs_create_file("set_event_notrace_pid", 0644, parent,
3457                                    tr, &ftrace_set_event_notrace_pid_fops);
3458        if (!entry)
3459                pr_warn("Could not create tracefs 'set_event_notrace_pid' entry\n");
3460
3461        /* ring buffer internal formats */
3462        entry = trace_create_file("header_page", 0444, d_events,
3463                                  ring_buffer_print_page_header,
3464                                  &ftrace_show_header_fops);
3465        if (!entry)
3466                pr_warn("Could not create tracefs 'header_page' entry\n");
3467
3468        entry = trace_create_file("header_event", 0444, d_events,
3469                                  ring_buffer_print_entry_header,
3470                                  &ftrace_show_header_fops);
3471        if (!entry)
3472                pr_warn("Could not create tracefs 'header_event' entry\n");
3473
3474        tr->event_dir = d_events;
3475
3476        return 0;
3477}
3478
3479/**
3480 * event_trace_add_tracer - add a instance of a trace_array to events
3481 * @parent: The parent dentry to place the files/directories for events in
3482 * @tr: The trace array associated with these events
3483 *
3484 * When a new instance is created, it needs to set up its events
3485 * directory, as well as other files associated with events. It also
3486 * creates the event hierarchy in the @parent/events directory.
3487 *
3488 * Returns 0 on success.
3489 *
3490 * Must be called with event_mutex held.
3491 */
3492int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3493{
3494        int ret;
3495
3496        lockdep_assert_held(&event_mutex);
3497
3498        ret = create_event_toplevel_files(parent, tr);
3499        if (ret)
3500                goto out;
3501
3502        down_write(&trace_event_sem);
3503        /* If tr already has the event list, it is initialized in early boot. */
3504        if (unlikely(!list_empty(&tr->events)))
3505                __trace_early_add_event_dirs(tr);
3506        else
3507                __trace_add_event_dirs(tr);
3508        up_write(&trace_event_sem);
3509
3510 out:
3511        return ret;
3512}
3513
3514/*
3515 * The top trace array already had its file descriptors created.
3516 * Now the files themselves need to be created.
3517 */
3518static __init int
3519early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3520{
3521        int ret;
3522
3523        mutex_lock(&event_mutex);
3524
3525        ret = create_event_toplevel_files(parent, tr);
3526        if (ret)
3527                goto out_unlock;
3528
3529        down_write(&trace_event_sem);
3530        __trace_early_add_event_dirs(tr);
3531        up_write(&trace_event_sem);
3532
3533 out_unlock:
3534        mutex_unlock(&event_mutex);
3535
3536        return ret;
3537}
3538
3539/* Must be called with event_mutex held */
3540int event_trace_del_tracer(struct trace_array *tr)
3541{
3542        lockdep_assert_held(&event_mutex);
3543
3544        /* Disable any event triggers and associated soft-disabled events */
3545        clear_event_triggers(tr);
3546
3547        /* Clear the pid list */
3548        __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3549
3550        /* Disable any running events */
3551        __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3552
3553        /* Make sure no more events are being executed */
3554        tracepoint_synchronize_unregister();
3555
3556        down_write(&trace_event_sem);
3557        __trace_remove_event_dirs(tr);
3558        tracefs_remove(tr->event_dir);
3559        up_write(&trace_event_sem);
3560
3561        tr->event_dir = NULL;
3562
3563        return 0;
3564}
3565
3566static __init int event_trace_memsetup(void)
3567{
3568        field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3569        file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3570        return 0;
3571}
3572
3573static __init void
3574early_enable_events(struct trace_array *tr, bool disable_first)
3575{
3576        char *buf = bootup_event_buf;
3577        char *token;
3578        int ret;
3579
3580        while (true) {
3581                token = strsep(&buf, ",");
3582
3583                if (!token)
3584                        break;
3585
3586                if (*token) {
3587                        /* Restarting syscalls requires that we stop them first */
3588                        if (disable_first)
3589                                ftrace_set_clr_event(tr, token, 0);
3590
3591                        ret = ftrace_set_clr_event(tr, token, 1);
3592                        if (ret)
3593                                pr_warn("Failed to enable trace event: %s\n", token);
3594                }
3595
3596                /* Put back the comma to allow this to be called again */
3597                if (buf)
3598                        *(buf - 1) = ',';
3599        }
3600}
3601
3602static __init int event_trace_enable(void)
3603{
3604        struct trace_array *tr = top_trace_array();
3605        struct trace_event_call **iter, *call;
3606        int ret;
3607
3608        if (!tr)
3609                return -ENODEV;
3610
3611        for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3612
3613                call = *iter;
3614                ret = event_init(call);
3615                if (!ret)
3616                        list_add(&call->list, &ftrace_events);
3617        }
3618
3619        /*
3620         * We need the top trace array to have a working set of trace
3621         * points at early init, before the debug files and directories
3622         * are created. Create the file entries now, and attach them
3623         * to the actual file dentries later.
3624         */
3625        __trace_early_add_events(tr);
3626
3627        early_enable_events(tr, false);
3628
3629        trace_printk_start_comm();
3630
3631        register_event_cmds();
3632
3633        register_trigger_cmds();
3634
3635        return 0;
3636}
3637
3638/*
3639 * event_trace_enable() is called from trace_event_init() first to
3640 * initialize events and perhaps start any events that are on the
3641 * command line. Unfortunately, there are some events that will not
3642 * start this early, like the system call tracepoints that need
3643 * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3644 * event_trace_enable() is called before pid 1 starts, and this flag
3645 * is never set, making the syscall tracepoint never get reached, but
3646 * the event is enabled regardless (and not doing anything).
3647 */
3648static __init int event_trace_enable_again(void)
3649{
3650        struct trace_array *tr;
3651
3652        tr = top_trace_array();
3653        if (!tr)
3654                return -ENODEV;
3655
3656        early_enable_events(tr, true);
3657
3658        return 0;
3659}
3660
3661early_initcall(event_trace_enable_again);
3662
3663/* Init fields which doesn't related to the tracefs */
3664static __init int event_trace_init_fields(void)
3665{
3666        if (trace_define_generic_fields())
3667                pr_warn("tracing: Failed to allocated generic fields");
3668
3669        if (trace_define_common_fields())
3670                pr_warn("tracing: Failed to allocate common fields");
3671
3672        return 0;
3673}
3674
3675__init int event_trace_init(void)
3676{
3677        struct trace_array *tr;
3678        struct dentry *entry;
3679        int ret;
3680
3681        tr = top_trace_array();
3682        if (!tr)
3683                return -ENODEV;
3684
3685        entry = tracefs_create_file("available_events", 0444, NULL,
3686                                    tr, &ftrace_avail_fops);
3687        if (!entry)
3688                pr_warn("Could not create tracefs 'available_events' entry\n");
3689
3690        ret = early_event_add_tracer(NULL, tr);
3691        if (ret)
3692                return ret;
3693
3694#ifdef CONFIG_MODULES
3695        ret = register_module_notifier(&trace_module_nb);
3696        if (ret)
3697                pr_warn("Failed to register trace events module notifier\n");
3698#endif
3699
3700        eventdir_initialized = true;
3701
3702        return 0;
3703}
3704
3705void __init trace_event_init(void)
3706{
3707        event_trace_memsetup();
3708        init_ftrace_syscalls();
3709        event_trace_enable();
3710        event_trace_init_fields();
3711}
3712
3713#ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3714
3715static DEFINE_SPINLOCK(test_spinlock);
3716static DEFINE_SPINLOCK(test_spinlock_irq);
3717static DEFINE_MUTEX(test_mutex);
3718
3719static __init void test_work(struct work_struct *dummy)
3720{
3721        spin_lock(&test_spinlock);
3722        spin_lock_irq(&test_spinlock_irq);
3723        udelay(1);
3724        spin_unlock_irq(&test_spinlock_irq);
3725        spin_unlock(&test_spinlock);
3726
3727        mutex_lock(&test_mutex);
3728        msleep(1);
3729        mutex_unlock(&test_mutex);
3730}
3731
3732static __init int event_test_thread(void *unused)
3733{
3734        void *test_malloc;
3735
3736        test_malloc = kmalloc(1234, GFP_KERNEL);
3737        if (!test_malloc)
3738                pr_info("failed to kmalloc\n");
3739
3740        schedule_on_each_cpu(test_work);
3741
3742        kfree(test_malloc);
3743
3744        set_current_state(TASK_INTERRUPTIBLE);
3745        while (!kthread_should_stop()) {
3746                schedule();
3747                set_current_state(TASK_INTERRUPTIBLE);
3748        }
3749        __set_current_state(TASK_RUNNING);
3750
3751        return 0;
3752}
3753
3754/*
3755 * Do various things that may trigger events.
3756 */
3757static __init void event_test_stuff(void)
3758{
3759        struct task_struct *test_thread;
3760
3761        test_thread = kthread_run(event_test_thread, NULL, "test-events");
3762        msleep(1);
3763        kthread_stop(test_thread);
3764}
3765
3766/*
3767 * For every trace event defined, we will test each trace point separately,
3768 * and then by groups, and finally all trace points.
3769 */
3770static __init void event_trace_self_tests(void)
3771{
3772        struct trace_subsystem_dir *dir;
3773        struct trace_event_file *file;
3774        struct trace_event_call *call;
3775        struct event_subsystem *system;
3776        struct trace_array *tr;
3777        int ret;
3778
3779        tr = top_trace_array();
3780        if (!tr)
3781                return;
3782
3783        pr_info("Running tests on trace events:\n");
3784
3785        list_for_each_entry(file, &tr->events, list) {
3786
3787                call = file->event_call;
3788
3789                /* Only test those that have a probe */
3790                if (!call->class || !call->class->probe)
3791                        continue;
3792
3793/*
3794 * Testing syscall events here is pretty useless, but
3795 * we still do it if configured. But this is time consuming.
3796 * What we really need is a user thread to perform the
3797 * syscalls as we test.
3798 */
3799#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3800                if (call->class->system &&
3801                    strcmp(call->class->system, "syscalls") == 0)
3802                        continue;
3803#endif
3804
3805                pr_info("Testing event %s: ", trace_event_name(call));
3806
3807                /*
3808                 * If an event is already enabled, someone is using
3809                 * it and the self test should not be on.
3810                 */
3811                if (file->flags & EVENT_FILE_FL_ENABLED) {
3812                        pr_warn("Enabled event during self test!\n");
3813                        WARN_ON_ONCE(1);
3814                        continue;
3815                }
3816
3817                ftrace_event_enable_disable(file, 1);
3818                event_test_stuff();
3819                ftrace_event_enable_disable(file, 0);
3820
3821                pr_cont("OK\n");
3822        }
3823
3824        /* Now test at the sub system level */
3825
3826        pr_info("Running tests on trace event systems:\n");
3827
3828        list_for_each_entry(dir, &tr->systems, list) {
3829
3830                system = dir->subsystem;
3831
3832                /* the ftrace system is special, skip it */
3833                if (strcmp(system->name, "ftrace") == 0)
3834                        continue;
3835
3836                pr_info("Testing event system %s: ", system->name);
3837
3838                ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3839                if (WARN_ON_ONCE(ret)) {
3840                        pr_warn("error enabling system %s\n",
3841                                system->name);
3842                        continue;
3843                }
3844
3845                event_test_stuff();
3846
3847                ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3848                if (WARN_ON_ONCE(ret)) {
3849                        pr_warn("error disabling system %s\n",
3850                                system->name);
3851                        continue;
3852                }
3853
3854                pr_cont("OK\n");
3855        }
3856
3857        /* Test with all events enabled */
3858
3859        pr_info("Running tests on all trace events:\n");
3860        pr_info("Testing all events: ");
3861
3862        ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3863        if (WARN_ON_ONCE(ret)) {
3864                pr_warn("error enabling all events\n");
3865                return;
3866        }
3867
3868        event_test_stuff();
3869
3870        /* reset sysname */
3871        ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3872        if (WARN_ON_ONCE(ret)) {
3873                pr_warn("error disabling all events\n");
3874                return;
3875        }
3876
3877        pr_cont("OK\n");
3878}
3879
3880#ifdef CONFIG_FUNCTION_TRACER
3881
3882static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3883
3884static struct trace_event_file event_trace_file __initdata;
3885
3886static void __init
3887function_test_events_call(unsigned long ip, unsigned long parent_ip,
3888                          struct ftrace_ops *op, struct ftrace_regs *regs)
3889{
3890        struct trace_buffer *buffer;
3891        struct ring_buffer_event *event;
3892        struct ftrace_entry *entry;
3893        unsigned int trace_ctx;
3894        long disabled;
3895        int cpu;
3896
3897        trace_ctx = tracing_gen_ctx();
3898        preempt_disable_notrace();
3899        cpu = raw_smp_processor_id();
3900        disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3901
3902        if (disabled != 1)
3903                goto out;
3904
3905        event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3906                                                TRACE_FN, sizeof(*entry),
3907                                                trace_ctx);
3908        if (!event)
3909                goto out;
3910        entry   = ring_buffer_event_data(event);
3911        entry->ip                       = ip;
3912        entry->parent_ip                = parent_ip;
3913
3914        event_trigger_unlock_commit(&event_trace_file, buffer, event,
3915                                    entry, trace_ctx);
3916 out:
3917        atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3918        preempt_enable_notrace();
3919}
3920
3921static struct ftrace_ops trace_ops __initdata  =
3922{
3923        .func = function_test_events_call,
3924};
3925
3926static __init void event_trace_self_test_with_function(void)
3927{
3928        int ret;
3929
3930        event_trace_file.tr = top_trace_array();
3931        if (WARN_ON(!event_trace_file.tr))
3932                return;
3933
3934        ret = register_ftrace_function(&trace_ops);
3935        if (WARN_ON(ret < 0)) {
3936                pr_info("Failed to enable function tracer for event tests\n");
3937                return;
3938        }
3939        pr_info("Running tests again, along with the function tracer\n");
3940        event_trace_self_tests();
3941        unregister_ftrace_function(&trace_ops);
3942}
3943#else
3944static __init void event_trace_self_test_with_function(void)
3945{
3946}
3947#endif
3948
3949static __init int event_trace_self_tests_init(void)
3950{
3951        if (!tracing_selftest_disabled) {
3952                event_trace_self_tests();
3953                event_trace_self_test_with_function();
3954        }
3955
3956        return 0;
3957}
3958
3959late_initcall(event_trace_self_tests_init);
3960
3961#endif
3962