kernel/trace/trace_events_synth.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_synth - synthetic trace events
   4  *
   5  * Copyright (C) 2015, 2020 Tom Zanussi <[email protected]>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kallsyms.h>
  10 #include <linux/security.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/stacktrace.h>
  14 #include <linux/rculist.h>
  15 #include <linux/tracefs.h>
  16
  17 /* for gfp flag names */
  18 #include <linux/trace_events.h>
  19 #include <trace/events/mmflags.h>
  20
  21 #include "trace_synth.h"
  22
  23 #undef ERRORS
  24 #define ERRORS  \
  25         C(BAD_NAME,             "Illegal name"),                \
  26         C(INVALID_CMD,          "Command must be of the form: <name> field[;field] ..."),\
  27         C(INVALID_DYN_CMD,      "Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
  28         C(EVENT_EXISTS,         "Event already exists"),        \
  29         C(TOO_MANY_FIELDS,      "Too many fields"),             \
  30         C(INCOMPLETE_TYPE,      "Incomplete type"),             \
  31         C(INVALID_TYPE,         "Invalid type"),                \
  32         C(INVALID_FIELD,        "Invalid field"),               \
  33         C(INVALID_ARRAY_SPEC,   "Invalid array specification"),
  34
  35 #undef C
  36 #define C(a, b)         SYNTH_ERR_##a
  37
  38 enum { ERRORS };
  39
  40 #undef C
  41 #define C(a, b)         b
  42
  43 static const char *err_text[] = { ERRORS };
  44
  45 static char last_cmd[MAX_FILTER_STR_VAL];
  46
  47 static int errpos(const char *str)
  48 {
  49         return err_pos(last_cmd, str);
  50 }
  51
  52 static void last_cmd_set(const char *str)
  53 {
  54         if (!str)
  55                 return;
  56
  57         strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
  58 }
  59
  60 static void synth_err(u8 err_type, u8 err_pos)
  61 {
  62         tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
  63                         err_type, err_pos);
  64 }
  65
  66 static int create_synth_event(const char *raw_command);
  67 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
  68 static int synth_event_release(struct dyn_event *ev);
  69 static bool synth_event_is_busy(struct dyn_event *ev);
  70 static bool synth_event_match(const char *system, const char *event,
  71                         int argc, const char **argv, struct dyn_event *ev);
  72
  73 static struct dyn_event_operations synth_event_ops = {
  74         .create = create_synth_event,
  75         .show = synth_event_show,
  76         .is_busy = synth_event_is_busy,
  77         .free = synth_event_release,
  78         .match = synth_event_match,
  79 };
  80
  81 static bool is_synth_event(struct dyn_event *ev)
  82 {
  83         return ev->ops == &synth_event_ops;
  84 }
  85
  86 static struct synth_event *to_synth_event(struct dyn_event *ev)
  87 {
  88         return container_of(ev, struct synth_event, devent);
  89 }
  90
  91 static bool synth_event_is_busy(struct dyn_event *ev)
  92 {
  93         struct synth_event *event = to_synth_event(ev);
  94
  95         return event->ref != 0;
  96 }
  97
  98 static bool synth_event_match(const char *system, const char *event,
  99                         int argc, const char **argv, struct dyn_event *ev)
 100 {
 101         struct synth_event *sev = to_synth_event(ev);
 102
 103         return strcmp(sev->name, event) == 0 &&
 104                 (!system || strcmp(system, SYNTH_SYSTEM) == 0);
 105 }
 106
 107 struct synth_trace_event {
 108         struct trace_entry      ent;
 109         u64                     fields[];
 110 };
 111
 112 static int synth_event_define_fields(struct trace_event_call *call)
 113 {
 114         struct synth_trace_event trace;
 115         int offset = offsetof(typeof(trace), fields);
 116         struct synth_event *event = call->data;
 117         unsigned int i, size, n_u64;
 118         char *name, *type;
 119         bool is_signed;
 120         int ret = 0;
 121
 122         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 123                 size = event->fields[i]->size;
 124                 is_signed = event->fields[i]->is_signed;
 125                 type = event->fields[i]->type;
 126                 name = event->fields[i]->name;
 127                 ret = trace_define_field(call, type, name, offset, size,
 128                                          is_signed, FILTER_OTHER);
 129                 if (ret)
 130                         break;
 131
 132                 event->fields[i]->offset = n_u64;
 133
 134                 if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
 135                         offset += STR_VAR_LEN_MAX;
 136                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 137                 } else {
 138                         offset += sizeof(u64);
 139                         n_u64++;
 140                 }
 141         }
 142
 143         event->n_u64 = n_u64;
 144
 145         return ret;
 146 }
 147
 148 static bool synth_field_signed(char *type)
 149 {
 150         if (str_has_prefix(type, "u"))
 151                 return false;
 152         if (strcmp(type, "gfp_t") == 0)
 153                 return false;
 154
 155         return true;
 156 }
 157
 158 static int synth_field_is_string(char *type)
 159 {
 160         if (strstr(type, "char[") != NULL)
 161                 return true;
 162
 163         return false;
 164 }
 165
 166 static int synth_field_string_size(char *type)
 167 {
 168         char buf[4], *end, *start;
 169         unsigned int len;
 170         int size, err;
 171
 172         start = strstr(type, "char[");
 173         if (start == NULL)
 174                 return -EINVAL;
 175         start += sizeof("char[") - 1;
 176
 177         end = strchr(type, ']');
 178         if (!end || end < start || type + strlen(type) > end + 1)
 179                 return -EINVAL;
 180
 181         len = end - start;
 182         if (len > 3)
 183                 return -EINVAL;
 184
 185         if (len == 0)
 186                 return 0; /* variable-length string */
 187
 188         strncpy(buf, start, len);
 189         buf[len] = '\0';
 190
 191         err = kstrtouint(buf, 0, &size);
 192         if (err)
 193                 return err;
 194
 195         if (size > STR_VAR_LEN_MAX)
 196                 return -EINVAL;
 197
 198         return size;
 199 }
 200
 201 static int synth_field_size(char *type)
 202 {
 203         int size = 0;
 204
 205         if (strcmp(type, "s64") == 0)
 206                 size = sizeof(s64);
 207         else if (strcmp(type, "u64") == 0)
 208                 size = sizeof(u64);
 209         else if (strcmp(type, "s32") == 0)
 210                 size = sizeof(s32);
 211         else if (strcmp(type, "u32") == 0)
 212                 size = sizeof(u32);
 213         else if (strcmp(type, "s16") == 0)
 214                 size = sizeof(s16);
 215         else if (strcmp(type, "u16") == 0)
 216                 size = sizeof(u16);
 217         else if (strcmp(type, "s8") == 0)
 218                 size = sizeof(s8);
 219         else if (strcmp(type, "u8") == 0)
 220                 size = sizeof(u8);
 221         else if (strcmp(type, "char") == 0)
 222                 size = sizeof(char);
 223         else if (strcmp(type, "unsigned char") == 0)
 224                 size = sizeof(unsigned char);
 225         else if (strcmp(type, "int") == 0)
 226                 size = sizeof(int);
 227         else if (strcmp(type, "unsigned int") == 0)
 228                 size = sizeof(unsigned int);
 229         else if (strcmp(type, "long") == 0)
 230                 size = sizeof(long);
 231         else if (strcmp(type, "unsigned long") == 0)
 232                 size = sizeof(unsigned long);
 233         else if (strcmp(type, "bool") == 0)
 234                 size = sizeof(bool);
 235         else if (strcmp(type, "pid_t") == 0)
 236                 size = sizeof(pid_t);
 237         else if (strcmp(type, "gfp_t") == 0)
 238                 size = sizeof(gfp_t);
 239         else if (synth_field_is_string(type))
 240                 size = synth_field_string_size(type);
 241
 242         return size;
 243 }
 244
 245 static const char *synth_field_fmt(char *type)
 246 {
 247         const char *fmt = "%llu";
 248
 249         if (strcmp(type, "s64") == 0)
 250                 fmt = "%lld";
 251         else if (strcmp(type, "u64") == 0)
 252                 fmt = "%llu";
 253         else if (strcmp(type, "s32") == 0)
 254                 fmt = "%d";
 255         else if (strcmp(type, "u32") == 0)
 256                 fmt = "%u";
 257         else if (strcmp(type, "s16") == 0)
 258                 fmt = "%d";
 259         else if (strcmp(type, "u16") == 0)
 260                 fmt = "%u";
 261         else if (strcmp(type, "s8") == 0)
 262                 fmt = "%d";
 263         else if (strcmp(type, "u8") == 0)
 264                 fmt = "%u";
 265         else if (strcmp(type, "char") == 0)
 266                 fmt = "%d";
 267         else if (strcmp(type, "unsigned char") == 0)
 268                 fmt = "%u";
 269         else if (strcmp(type, "int") == 0)
 270                 fmt = "%d";
 271         else if (strcmp(type, "unsigned int") == 0)
 272                 fmt = "%u";
 273         else if (strcmp(type, "long") == 0)
 274                 fmt = "%ld";
 275         else if (strcmp(type, "unsigned long") == 0)
 276                 fmt = "%lu";
 277         else if (strcmp(type, "bool") == 0)
 278                 fmt = "%d";
 279         else if (strcmp(type, "pid_t") == 0)
 280                 fmt = "%d";
 281         else if (strcmp(type, "gfp_t") == 0)
 282                 fmt = "%x";
 283         else if (synth_field_is_string(type))
 284                 fmt = "%.*s";
 285
 286         return fmt;
 287 }
 288
 289 static void print_synth_event_num_val(struct trace_seq *s,
 290                                       char *print_fmt, char *name,
 291                                       int size, u64 val, char *space)
 292 {
 293         switch (size) {
 294         case 1:
 295                 trace_seq_printf(s, print_fmt, name, (u8)val, space);
 296                 break;
 297
 298         case 2:
 299                 trace_seq_printf(s, print_fmt, name, (u16)val, space);
 300                 break;
 301
 302         case 4:
 303                 trace_seq_printf(s, print_fmt, name, (u32)val, space);
 304                 break;
 305
 306         default:
 307                 trace_seq_printf(s, print_fmt, name, val, space);
 308                 break;
 309         }
 310 }
 311
 312 static enum print_line_t print_synth_event(struct trace_iterator *iter,
 313                                            int flags,
 314                                            struct trace_event *event)
 315 {
 316         struct trace_array *tr = iter->tr;
 317         struct trace_seq *s = &iter->seq;
 318         struct synth_trace_event *entry;
 319         struct synth_event *se;
 320         unsigned int i, n_u64;
 321         char print_fmt[32];
 322         const char *fmt;
 323
 324         entry = (struct synth_trace_event *)iter->ent;
 325         se = container_of(event, struct synth_event, call.event);
 326
 327         trace_seq_printf(s, "%s: ", se->name);
 328
 329         for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
 330                 if (trace_seq_has_overflowed(s))
 331                         goto end;
 332
 333                 fmt = synth_field_fmt(se->fields[i]->type);
 334
 335                 /* parameter types */
 336                 if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
 337                         trace_seq_printf(s, "%s ", fmt);
 338
 339                 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
 340
 341                 /* parameter values */
 342                 if (se->fields[i]->is_string) {
 343                         if (se->fields[i]->is_dynamic) {
 344                                 u32 offset, data_offset;
 345                                 char *str_field;
 346
 347                                 offset = (u32)entry->fields[n_u64];
 348                                 data_offset = offset & 0xffff;
 349
 350                                 str_field = (char *)entry + data_offset;
 351
 352                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 353                                                  STR_VAR_LEN_MAX,
 354                                                  str_field,
 355                                                  i == se->n_fields - 1 ? "" : " ");
 356                                 n_u64++;
 357                         } else {
 358                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 359                                                  STR_VAR_LEN_MAX,
 360                                                  (char *)&entry->fields[n_u64],
 361                                                  i == se->n_fields - 1 ? "" : " ");
 362                                 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 363                         }
 364                 } else {
 365                         struct trace_print_flags __flags[] = {
 366                             __def_gfpflag_names, {-1, NULL} };
 367                         char *space = (i == se->n_fields - 1 ? "" : " ");
 368
 369                         print_synth_event_num_val(s, print_fmt,
 370                                                   se->fields[i]->name,
 371                                                   se->fields[i]->size,
 372                                                   entry->fields[n_u64],
 373                                                   space);
 374
 375                         if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
 376                                 trace_seq_puts(s, " (");
 377                                 trace_print_flags_seq(s, "|",
 378                                                       entry->fields[n_u64],
 379                                                       __flags);
 380                                 trace_seq_putc(s, ')');
 381                         }
 382                         n_u64++;
 383                 }
 384         }
 385 end:
 386         trace_seq_putc(s, '\n');
 387
 388         return trace_handle_return(s);
 389 }
 390
 391 static struct trace_event_functions synth_event_funcs = {
 392         .trace          = print_synth_event
 393 };
 394
 395 static unsigned int trace_string(struct synth_trace_event *entry,
 396                                  struct synth_event *event,
 397                                  char *str_val,
 398                                  bool is_dynamic,
 399                                  unsigned int data_size,
 400                                  unsigned int *n_u64)
 401 {
 402         unsigned int len = 0;
 403         char *str_field;
 404
 405         if (is_dynamic) {
 406                 u32 data_offset;
 407
 408                 data_offset = offsetof(typeof(*entry), fields);
 409                 data_offset += event->n_u64 * sizeof(u64);
 410                 data_offset += data_size;
 411
 412                 str_field = (char *)entry + data_offset;
 413
 414                 len = strlen(str_val) + 1;
 415                 strscpy(str_field, str_val, len);
 416
 417                 data_offset |= len << 16;
 418                 *(u32 *)&entry->fields[*n_u64] = data_offset;
 419
 420                 (*n_u64)++;
 421         } else {
 422                 str_field = (char *)&entry->fields[*n_u64];
 423
 424                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
 425                 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
 426         }
 427
 428         return len;
 429 }
 430
 431 static notrace void trace_event_raw_event_synth(void *__data,
 432                                                 u64 *var_ref_vals,
 433                                                 unsigned int *var_ref_idx)
 434 {
 435         unsigned int i, n_u64, val_idx, len, data_size = 0;
 436         struct trace_event_file *trace_file = __data;
 437         struct synth_trace_event *entry;
 438         struct trace_event_buffer fbuffer;
 439         struct trace_buffer *buffer;
 440         struct synth_event *event;
 441         int fields_size = 0;
 442
 443         event = trace_file->event_call->data;
 444
 445         if (trace_trigger_soft_disabled(trace_file))
 446                 return;
 447
 448         fields_size = event->n_u64 * sizeof(u64);
 449
 450         for (i = 0; i < event->n_dynamic_fields; i++) {
 451                 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
 452                 char *str_val;
 453
 454                 val_idx = var_ref_idx[field_pos];
 455                 str_val = (char *)(long)var_ref_vals[val_idx];
 456
 457                 len = strlen(str_val) + 1;
 458
 459                 fields_size += len;
 460         }
 461
 462         /*
 463          * Avoid ring buffer recursion detection, as this event
 464          * is being performed within another event.
 465          */
 466         buffer = trace_file->tr->array_buffer.buffer;
 467         ring_buffer_nest_start(buffer);
 468
 469         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 470                                            sizeof(*entry) + fields_size);
 471         if (!entry)
 472                 goto out;
 473
 474         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 475                 val_idx = var_ref_idx[i];
 476                 if (event->fields[i]->is_string) {
 477                         char *str_val = (char *)(long)var_ref_vals[val_idx];
 478
 479                         len = trace_string(entry, event, str_val,
 480                                            event->fields[i]->is_dynamic,
 481                                            data_size, &n_u64);
 482                         data_size += len; /* only dynamic string increments */
 483                 } else {
 484                         struct synth_field *field = event->fields[i];
 485                         u64 val = var_ref_vals[val_idx];
 486
 487                         switch (field->size) {
 488                         case 1:
 489                                 *(u8 *)&entry->fields[n_u64] = (u8)val;
 490                                 break;
 491
 492                         case 2:
 493                                 *(u16 *)&entry->fields[n_u64] = (u16)val;
 494                                 break;
 495
 496                         case 4:
 497                                 *(u32 *)&entry->fields[n_u64] = (u32)val;
 498                                 break;
 499
 500                         default:
 501                                 entry->fields[n_u64] = val;
 502                                 break;
 503                         }
 504                         n_u64++;
 505                 }
 506         }
 507
 508         trace_event_buffer_commit(&fbuffer);
 509 out:
 510         ring_buffer_nest_end(buffer);
 511 }
 512
 513 static void free_synth_event_print_fmt(struct trace_event_call *call)
 514 {
 515         if (call) {
 516                 kfree(call->print_fmt);
 517                 call->print_fmt = NULL;
 518         }
 519 }
 520
 521 static int __set_synth_event_print_fmt(struct synth_event *event,
 522                                        char *buf, int len)
 523 {
 524         const char *fmt;
 525         int pos = 0;
 526         int i;
 527
 528         /* When len=0, we just calculate the needed length */
 529 #define LEN_OR_ZERO (len ? len - pos : 0)
 530
 531         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 532         for (i = 0; i < event->n_fields; i++) {
 533                 fmt = synth_field_fmt(event->fields[i]->type);
 534                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 535                                 event->fields[i]->name, fmt,
 536                                 i == event->n_fields - 1 ? "" : ", ");
 537         }
 538         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 539
 540         for (i = 0; i < event->n_fields; i++) {
 541                 if (event->fields[i]->is_string &&
 542                     event->fields[i]->is_dynamic)
 543                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 544                                 ", __get_str(%s)", event->fields[i]->name);
 545                 else
 546                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 547                                         ", REC->%s", event->fields[i]->name);
 548         }
 549
 550 #undef LEN_OR_ZERO
 551
 552         /* return the length of print_fmt */
 553         return pos;
 554 }
 555
 556 static int set_synth_event_print_fmt(struct trace_event_call *call)
 557 {
 558         struct synth_event *event = call->data;
 559         char *print_fmt;
 560         int len;
 561
 562         /* First: called with 0 length to calculate the needed length */
 563         len = __set_synth_event_print_fmt(event, NULL, 0);
 564
 565         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 566         if (!print_fmt)
 567                 return -ENOMEM;
 568
 569         /* Second: actually write the @print_fmt */
 570         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 571         call->print_fmt = print_fmt;
 572
 573         return 0;
 574 }
 575
 576 static void free_synth_field(struct synth_field *field)
 577 {
 578         kfree(field->type);
 579         kfree(field->name);
 580         kfree(field);
 581 }
 582
 583 static int check_field_version(const char *prefix, const char *field_type,
 584                                const char *field_name)
 585 {
 586         /*
 587          * For backward compatibility, the old synthetic event command
 588          * format did not require semicolons, and in order to not
 589          * break user space, that old format must still work. If a new
 590          * feature is added, then the format that uses the new feature
 591          * will be required to have semicolons, as nothing that uses
 592          * the old format would be using the new, yet to be created,
 593          * feature. When a new feature is added, this will detect it,
 594          * and return a number greater than 1, and require the format
 595          * to use semicolons.
 596          */
 597         return 1;
 598 }
 599
 600 static struct synth_field *parse_synth_field(int argc, char **argv,
 601                                              int *consumed, int *field_version)
 602 {
 603         const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 604         struct synth_field *field;
 605         int len, ret = -ENOMEM;
 606         struct seq_buf s;
 607         ssize_t size;
 608
 609         if (!strcmp(field_type, "unsigned")) {
 610                 if (argc < 3) {
 611                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 612                         return ERR_PTR(-EINVAL);
 613                 }
 614                 prefix = "unsigned ";
 615                 field_type = argv[1];
 616                 field_name = argv[2];
 617                 *consumed += 3;
 618         } else {
 619                 field_name = argv[1];
 620                 *consumed += 2;
 621         }
 622
 623         if (!field_name) {
 624                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
 625                 return ERR_PTR(-EINVAL);
 626         }
 627
 628         *field_version = check_field_version(prefix, field_type, field_name);
 629
 630         field = kzalloc(sizeof(*field), GFP_KERNEL);
 631         if (!field)
 632                 return ERR_PTR(-ENOMEM);
 633
 634         len = strlen(field_name);
 635         array = strchr(field_name, '[');
 636         if (array)
 637                 len -= strlen(array);
 638
 639         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 640         if (!field->name)
 641                 goto free;
 642
 643         if (!is_good_name(field->name)) {
 644                 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 645                 ret = -EINVAL;
 646                 goto free;
 647         }
 648
 649         len = strlen(field_type) + 1;
 650
 651         if (array)
 652                 len += strlen(array);
 653
 654         if (prefix)
 655                 len += strlen(prefix);
 656
 657         field->type = kzalloc(len, GFP_KERNEL);
 658         if (!field->type)
 659                 goto free;
 660
 661         seq_buf_init(&s, field->type, len);
 662         if (prefix)
 663                 seq_buf_puts(&s, prefix);
 664         seq_buf_puts(&s, field_type);
 665         if (array)
 666                 seq_buf_puts(&s, array);
 667         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 668                 goto free;
 669
 670         s.buffer[s.len] = '\0';
 671
 672         size = synth_field_size(field->type);
 673         if (size < 0) {
 674                 if (array)
 675                         synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
 676                 else
 677                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 678                 ret = -EINVAL;
 679                 goto free;
 680         } else if (size == 0) {
 681                 if (synth_field_is_string(field->type)) {
 682                         char *type;
 683
 684                         len = sizeof("__data_loc ") + strlen(field->type) + 1;
 685                         type = kzalloc(len, GFP_KERNEL);
 686                         if (!type)
 687                                 goto free;
 688
 689                         seq_buf_init(&s, type, len);
 690                         seq_buf_puts(&s, "__data_loc ");
 691                         seq_buf_puts(&s, field->type);
 692
 693                         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 694                                 goto free;
 695                         s.buffer[s.len] = '\0';
 696
 697                         kfree(field->type);
 698                         field->type = type;
 699
 700                         field->is_dynamic = true;
 701                         size = sizeof(u64);
 702                 } else {
 703                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 704                         ret = -EINVAL;
 705                         goto free;
 706                 }
 707         }
 708         field->size = size;
 709
 710         if (synth_field_is_string(field->type))
 711                 field->is_string = true;
 712
 713         field->is_signed = synth_field_signed(field->type);
 714  out:
 715         return field;
 716  free:
 717         free_synth_field(field);
 718         field = ERR_PTR(ret);
 719         goto out;
 720 }
 721
 722 static void free_synth_tracepoint(struct tracepoint *tp)
 723 {
 724         if (!tp)
 725                 return;
 726
 727         kfree(tp->name);
 728         kfree(tp);
 729 }
 730
 731 static struct tracepoint *alloc_synth_tracepoint(char *name)
 732 {
 733         struct tracepoint *tp;
 734
 735         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 736         if (!tp)
 737                 return ERR_PTR(-ENOMEM);
 738
 739         tp->name = kstrdup(name, GFP_KERNEL);
 740         if (!tp->name) {
 741                 kfree(tp);
 742                 return ERR_PTR(-ENOMEM);
 743         }
 744
 745         return tp;
 746 }
 747
 748 struct synth_event *find_synth_event(const char *name)
 749 {
 750         struct dyn_event *pos;
 751         struct synth_event *event;
 752
 753         for_each_dyn_event(pos) {
 754                 if (!is_synth_event(pos))
 755                         continue;
 756                 event = to_synth_event(pos);
 757                 if (strcmp(event->name, name) == 0)
 758                         return event;
 759         }
 760
 761         return NULL;
 762 }
 763
 764 static struct trace_event_fields synth_event_fields_array[] = {
 765         { .type = TRACE_FUNCTION_TYPE,
 766           .define_fields = synth_event_define_fields },
 767         {}
 768 };
 769
 770 static int register_synth_event(struct synth_event *event)
 771 {
 772         struct trace_event_call *call = &event->call;
 773         int ret = 0;
 774
 775         event->call.class = &event->class;
 776         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 777         if (!event->class.system) {
 778                 ret = -ENOMEM;
 779                 goto out;
 780         }
 781
 782         event->tp = alloc_synth_tracepoint(event->name);
 783         if (IS_ERR(event->tp)) {
 784                 ret = PTR_ERR(event->tp);
 785                 event->tp = NULL;
 786                 goto out;
 787         }
 788
 789         INIT_LIST_HEAD(&call->class->fields);
 790         call->event.funcs = &synth_event_funcs;
 791         call->class->fields_array = synth_event_fields_array;
 792
 793         ret = register_trace_event(&call->event);
 794         if (!ret) {
 795                 ret = -ENODEV;
 796                 goto out;
 797         }
 798         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 799         call->class->reg = trace_event_reg;
 800         call->class->probe = trace_event_raw_event_synth;
 801         call->data = event;
 802         call->tp = event->tp;
 803
 804         ret = trace_add_event_call(call);
 805         if (ret) {
 806                 pr_warn("Failed to register synthetic event: %s\n",
 807                         trace_event_name(call));
 808                 goto err;
 809         }
 810
 811         ret = set_synth_event_print_fmt(call);
 812         if (ret < 0) {
 813                 trace_remove_event_call(call);
 814                 goto err;
 815         }
 816  out:
 817         return ret;
 818  err:
 819         unregister_trace_event(&call->event);
 820         goto out;
 821 }
 822
 823 static int unregister_synth_event(struct synth_event *event)
 824 {
 825         struct trace_event_call *call = &event->call;
 826         int ret;
 827
 828         ret = trace_remove_event_call(call);
 829
 830         return ret;
 831 }
 832
 833 static void free_synth_event(struct synth_event *event)
 834 {
 835         unsigned int i;
 836
 837         if (!event)
 838                 return;
 839
 840         for (i = 0; i < event->n_fields; i++)
 841                 free_synth_field(event->fields[i]);
 842
 843         kfree(event->fields);
 844         kfree(event->dynamic_fields);
 845         kfree(event->name);
 846         kfree(event->class.system);
 847         free_synth_tracepoint(event->tp);
 848         free_synth_event_print_fmt(&event->call);
 849         kfree(event);
 850 }
 851
 852 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 853                                              struct synth_field **fields)
 854 {
 855         unsigned int i, j, n_dynamic_fields = 0;
 856         struct synth_event *event;
 857
 858         event = kzalloc(sizeof(*event), GFP_KERNEL);
 859         if (!event) {
 860                 event = ERR_PTR(-ENOMEM);
 861                 goto out;
 862         }
 863
 864         event->name = kstrdup(name, GFP_KERNEL);
 865         if (!event->name) {
 866                 kfree(event);
 867                 event = ERR_PTR(-ENOMEM);
 868                 goto out;
 869         }
 870
 871         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 872         if (!event->fields) {
 873                 free_synth_event(event);
 874                 event = ERR_PTR(-ENOMEM);
 875                 goto out;
 876         }
 877
 878         for (i = 0; i < n_fields; i++)
 879                 if (fields[i]->is_dynamic)
 880                         n_dynamic_fields++;
 881
 882         if (n_dynamic_fields) {
 883                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 884                                                 sizeof(*event->dynamic_fields),
 885                                                 GFP_KERNEL);
 886                 if (!event->dynamic_fields) {
 887                         free_synth_event(event);
 888                         event = ERR_PTR(-ENOMEM);
 889                         goto out;
 890                 }
 891         }
 892
 893         dyn_event_init(&event->devent, &synth_event_ops);
 894
 895         for (i = 0, j = 0; i < n_fields; i++) {
 896                 event->fields[i] = fields[i];
 897
 898                 if (fields[i]->is_dynamic) {
 899                         event->dynamic_fields[j] = fields[i];
 900                         event->dynamic_fields[j]->field_pos = i;
 901                         event->dynamic_fields[j++] = fields[i];
 902                         event->n_dynamic_fields++;
 903                 }
 904         }
 905         event->n_fields = n_fields;
 906  out:
 907         return event;
 908 }
 909
 910 static int synth_event_check_arg_fn(void *data)
 911 {
 912         struct dynevent_arg_pair *arg_pair = data;
 913         int size;
 914
 915         size = synth_field_size((char *)arg_pair->lhs);
 916         if (size == 0) {
 917                 if (strstr((char *)arg_pair->lhs, "["))
 918                         return 0;
 919         }
 920
 921         return size ? 0 : -EINVAL;
 922 }
 923
 924 /**
 925  * synth_event_add_field - Add a new field to a synthetic event cmd
 926  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 927  * @type: The type of the new field to add
 928  * @name: The name of the new field to add
 929  *
 930  * Add a new field to a synthetic event cmd object.  Field ordering is in
 931  * the same order the fields are added.
 932  *
 933  * See synth_field_size() for available types. If field_name contains
 934  * [n] the field is considered to be an array.
 935  *
 936  * Return: 0 if successful, error otherwise.
 937  */
 938 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
 939                           const char *name)
 940 {
 941         struct dynevent_arg_pair arg_pair;
 942         int ret;
 943
 944         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 945                 return -EINVAL;
 946
 947         if (!type || !name)
 948                 return -EINVAL;
 949
 950         dynevent_arg_pair_init(&arg_pair, 0, ';');
 951
 952         arg_pair.lhs = type;
 953         arg_pair.rhs = name;
 954
 955         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
 956         if (ret)
 957                 return ret;
 958
 959         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 960                 ret = -EINVAL;
 961
 962         return ret;
 963 }
 964 EXPORT_SYMBOL_GPL(synth_event_add_field);
 965
 966 /**
 967  * synth_event_add_field_str - Add a new field to a synthetic event cmd
 968  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 969  * @type_name: The type and name of the new field to add, as a single string
 970  *
 971  * Add a new field to a synthetic event cmd object, as a single
 972  * string.  The @type_name string is expected to be of the form 'type
 973  * name', which will be appended by ';'.  No sanity checking is done -
 974  * what's passed in is assumed to already be well-formed.  Field
 975  * ordering is in the same order the fields are added.
 976  *
 977  * See synth_field_size() for available types. If field_name contains
 978  * [n] the field is considered to be an array.
 979  *
 980  * Return: 0 if successful, error otherwise.
 981  */
 982 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
 983 {
 984         struct dynevent_arg arg;
 985         int ret;
 986
 987         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 988                 return -EINVAL;
 989
 990         if (!type_name)
 991                 return -EINVAL;
 992
 993         dynevent_arg_init(&arg, ';');
 994
 995         arg.str = type_name;
 996
 997         ret = dynevent_arg_add(cmd, &arg, NULL);
 998         if (ret)
 999                 return ret;
1000
1001         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1002                 ret = -EINVAL;
1003
1004         return ret;
1005 }
1006 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1007
1008 /**
1009  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1010  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1011  * @fields: An array of type/name field descriptions
1012  * @n_fields: The number of field descriptions contained in the fields array
1013  *
1014  * Add a new set of fields to a synthetic event cmd object.  The event
1015  * fields that will be defined for the event should be passed in as an
1016  * array of struct synth_field_desc, and the number of elements in the
1017  * array passed in as n_fields.  Field ordering will retain the
1018  * ordering given in the fields array.
1019  *
1020  * See synth_field_size() for available types. If field_name contains
1021  * [n] the field is considered to be an array.
1022  *
1023  * Return: 0 if successful, error otherwise.
1024  */
1025 int synth_event_add_fields(struct dynevent_cmd *cmd,
1026                            struct synth_field_desc *fields,
1027                            unsigned int n_fields)
1028 {
1029         unsigned int i;
1030         int ret = 0;
1031
1032         for (i = 0; i < n_fields; i++) {
1033                 if (fields[i].type == NULL || fields[i].name == NULL) {
1034                         ret = -EINVAL;
1035                         break;
1036                 }
1037
1038                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1039                 if (ret)
1040                         break;
1041         }
1042
1043         return ret;
1044 }
1045 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1046
1047 /**
1048  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1049  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1050  * @name: The name of the synthetic event
1051  * @mod: The module creating the event, NULL if not created from a module
1052  * @args: Variable number of arg (pairs), one pair for each field
1053  *
1054  * NOTE: Users normally won't want to call this function directly, but
1055  * rather use the synth_event_gen_cmd_start() wrapper, which
1056  * automatically adds a NULL to the end of the arg list.  If this
1057  * function is used directly, make sure the last arg in the variable
1058  * arg list is NULL.
1059  *
1060  * Generate a synthetic event command to be executed by
1061  * synth_event_gen_cmd_end().  This function can be used to generate
1062  * the complete command or only the first part of it; in the latter
1063  * case, synth_event_add_field(), synth_event_add_field_str(), or
1064  * synth_event_add_fields() can be used to add more fields following
1065  * this.
1066  *
1067  * There should be an even number variable args, each pair consisting
1068  * of a type followed by a field name.
1069  *
1070  * See synth_field_size() for available types. If field_name contains
1071  * [n] the field is considered to be an array.
1072  *
1073  * Return: 0 if successful, error otherwise.
1074  */
1075 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1076                                 struct module *mod, ...)
1077 {
1078         struct dynevent_arg arg;
1079         va_list args;
1080         int ret;
1081
1082         cmd->event_name = name;
1083         cmd->private_data = mod;
1084
1085         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1086                 return -EINVAL;
1087
1088         dynevent_arg_init(&arg, 0);
1089         arg.str = name;
1090         ret = dynevent_arg_add(cmd, &arg, NULL);
1091         if (ret)
1092                 return ret;
1093
1094         va_start(args, mod);
1095         for (;;) {
1096                 const char *type, *name;
1097
1098                 type = va_arg(args, const char *);
1099                 if (!type)
1100                         break;
1101                 name = va_arg(args, const char *);
1102                 if (!name)
1103                         break;
1104
1105                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1106                         ret = -EINVAL;
1107                         break;
1108                 }
1109
1110                 ret = synth_event_add_field(cmd, type, name);
1111                 if (ret)
1112                         break;
1113         }
1114         va_end(args);
1115
1116         return ret;
1117 }
1118 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1119
1120 /**
1121  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1122  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1123  * @name: The name of the synthetic event
1124  * @fields: An array of type/name field descriptions
1125  * @n_fields: The number of field descriptions contained in the fields array
1126  *
1127  * Generate a synthetic event command to be executed by
1128  * synth_event_gen_cmd_end().  This function can be used to generate
1129  * the complete command or only the first part of it; in the latter
1130  * case, synth_event_add_field(), synth_event_add_field_str(), or
1131  * synth_event_add_fields() can be used to add more fields following
1132  * this.
1133  *
1134  * The event fields that will be defined for the event should be
1135  * passed in as an array of struct synth_field_desc, and the number of
1136  * elements in the array passed in as n_fields.  Field ordering will
1137  * retain the ordering given in the fields array.
1138  *
1139  * See synth_field_size() for available types. If field_name contains
1140  * [n] the field is considered to be an array.
1141  *
1142  * Return: 0 if successful, error otherwise.
1143  */
1144 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1145                                     struct module *mod,
1146                                     struct synth_field_desc *fields,
1147                                     unsigned int n_fields)
1148 {
1149         struct dynevent_arg arg;
1150         unsigned int i;
1151         int ret = 0;
1152
1153         cmd->event_name = name;
1154         cmd->private_data = mod;
1155
1156         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1157                 return -EINVAL;
1158
1159         if (n_fields > SYNTH_FIELDS_MAX)
1160                 return -EINVAL;
1161
1162         dynevent_arg_init(&arg, 0);
1163         arg.str = name;
1164         ret = dynevent_arg_add(cmd, &arg, NULL);
1165         if (ret)
1166                 return ret;
1167
1168         for (i = 0; i < n_fields; i++) {
1169                 if (fields[i].type == NULL || fields[i].name == NULL)
1170                         return -EINVAL;
1171
1172                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1173                 if (ret)
1174                         break;
1175         }
1176
1177         return ret;
1178 }
1179 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1180
1181 static int __create_synth_event(const char *name, const char *raw_fields)
1182 {
1183         char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1184         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1185         int consumed, cmd_version = 1, n_fields_this_loop;
1186         int i, argc, n_fields = 0, ret = 0;
1187         struct synth_event *event = NULL;
1188
1189         /*
1190          * Argument syntax:
1191          *  - Add synthetic event: <event_name> field[;field] ...
1192          *  - Remove synthetic event: !<event_name> field[;field] ...
1193          *      where 'field' = type field_name
1194          */
1195
1196         if (name[0] == '\0') {
1197                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1198                 return -EINVAL;
1199         }
1200
1201         if (!is_good_name(name)) {
1202                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1203                 return -EINVAL;
1204         }
1205
1206         mutex_lock(&event_mutex);
1207
1208         event = find_synth_event(name);
1209         if (event) {
1210                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1211                 ret = -EEXIST;
1212                 goto err;
1213         }
1214
1215         tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1216         if (!tmp_fields) {
1217                 ret = -ENOMEM;
1218                 goto err;
1219         }
1220
1221         while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1222                 argv = argv_split(GFP_KERNEL, field_str, &argc);
1223                 if (!argv) {
1224                         ret = -ENOMEM;
1225                         goto err;
1226                 }
1227
1228                 if (!argc) {
1229                         argv_free(argv);
1230                         continue;
1231                 }
1232
1233                 n_fields_this_loop = 0;
1234                 consumed = 0;
1235                 while (argc > consumed) {
1236                         int field_version;
1237
1238                         field = parse_synth_field(argc - consumed,
1239                                                   argv + consumed, &consumed,
1240                                                   &field_version);
1241                         if (IS_ERR(field)) {
1242                                 argv_free(argv);
1243                                 ret = PTR_ERR(field);
1244                                 goto err;
1245                         }
1246
1247                         /*
1248                          * Track the highest version of any field we
1249                          * found in the command.
1250                          */
1251                         if (field_version > cmd_version)
1252                                 cmd_version = field_version;
1253
1254                         /*
1255                          * Now sort out what is and isn't valid for
1256                          * each supported version.
1257                          *
1258                          * If we see more than 1 field per loop, it
1259                          * means we have multiple fields between
1260                          * semicolons, and that's something we no
1261                          * longer support in a version 2 or greater
1262                          * command.
1263                          */
1264                         if (cmd_version > 1 && n_fields_this_loop >= 1) {
1265                                 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1266                                 ret = -EINVAL;
1267                                 goto err;
1268                         }
1269
1270                         fields[n_fields++] = field;
1271                         if (n_fields == SYNTH_FIELDS_MAX) {
1272                                 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1273                                 ret = -EINVAL;
1274                                 goto err;
1275                         }
1276
1277                         n_fields_this_loop++;
1278                 }
1279
1280                 if (consumed < argc) {
1281                         synth_err(SYNTH_ERR_INVALID_CMD, 0);
1282                         ret = -EINVAL;
1283                         goto err;
1284                 }
1285
1286                 argv_free(argv);
1287         }
1288
1289         if (n_fields == 0) {
1290                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1291                 ret = -EINVAL;
1292                 goto err;
1293         }
1294
1295         event = alloc_synth_event(name, n_fields, fields);
1296         if (IS_ERR(event)) {
1297                 ret = PTR_ERR(event);
1298                 event = NULL;
1299                 goto err;
1300         }
1301         ret = register_synth_event(event);
1302         if (!ret)
1303                 dyn_event_add(&event->devent);
1304         else
1305                 free_synth_event(event);
1306  out:
1307         mutex_unlock(&event_mutex);
1308
1309         kfree(saved_fields);
1310
1311         return ret;
1312  err:
1313         for (i = 0; i < n_fields; i++)
1314                 free_synth_field(fields[i]);
1315
1316         goto out;
1317 }
1318
1319 /**
1320  * synth_event_create - Create a new synthetic event
1321  * @name: The name of the new synthetic event
1322  * @fields: An array of type/name field descriptions
1323  * @n_fields: The number of field descriptions contained in the fields array
1324  * @mod: The module creating the event, NULL if not created from a module
1325  *
1326  * Create a new synthetic event with the given name under the
1327  * trace/events/synthetic/ directory.  The event fields that will be
1328  * defined for the event should be passed in as an array of struct
1329  * synth_field_desc, and the number elements in the array passed in as
1330  * n_fields. Field ordering will retain the ordering given in the
1331  * fields array.
1332  *
1333  * If the new synthetic event is being created from a module, the mod
1334  * param must be non-NULL.  This will ensure that the trace buffer
1335  * won't contain unreadable events.
1336  *
1337  * The new synth event should be deleted using synth_event_delete()
1338  * function.  The new synthetic event can be generated from modules or
1339  * other kernel code using trace_synth_event() and related functions.
1340  *
1341  * Return: 0 if successful, error otherwise.
1342  */
1343 int synth_event_create(const char *name, struct synth_field_desc *fields,
1344                        unsigned int n_fields, struct module *mod)
1345 {
1346         struct dynevent_cmd cmd;
1347         char *buf;
1348         int ret;
1349
1350         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1351         if (!buf)
1352                 return -ENOMEM;
1353
1354         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1355
1356         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1357                                               fields, n_fields);
1358         if (ret)
1359                 goto out;
1360
1361         ret = synth_event_gen_cmd_end(&cmd);
1362  out:
1363         kfree(buf);
1364
1365         return ret;
1366 }
1367 EXPORT_SYMBOL_GPL(synth_event_create);
1368
1369 static int destroy_synth_event(struct synth_event *se)
1370 {
1371         int ret;
1372
1373         if (se->ref)
1374                 ret = -EBUSY;
1375         else {
1376                 ret = unregister_synth_event(se);
1377                 if (!ret) {
1378                         dyn_event_remove(&se->devent);
1379                         free_synth_event(se);
1380                 }
1381         }
1382
1383         return ret;
1384 }
1385
1386 /**
1387  * synth_event_delete - Delete a synthetic event
1388  * @event_name: The name of the new synthetic event
1389  *
1390  * Delete a synthetic event that was created with synth_event_create().
1391  *
1392  * Return: 0 if successful, error otherwise.
1393  */
1394 int synth_event_delete(const char *event_name)
1395 {
1396         struct synth_event *se = NULL;
1397         struct module *mod = NULL;
1398         int ret = -ENOENT;
1399
1400         mutex_lock(&event_mutex);
1401         se = find_synth_event(event_name);
1402         if (se) {
1403                 mod = se->mod;
1404                 ret = destroy_synth_event(se);
1405         }
1406         mutex_unlock(&event_mutex);
1407
1408         if (mod) {
1409                 mutex_lock(&trace_types_lock);
1410                 /*
1411                  * It is safest to reset the ring buffer if the module
1412                  * being unloaded registered any events that were
1413                  * used. The only worry is if a new module gets
1414                  * loaded, and takes on the same id as the events of
1415                  * this module. When printing out the buffer, traced
1416                  * events left over from this module may be passed to
1417                  * the new module events and unexpected results may
1418                  * occur.
1419                  */
1420                 tracing_reset_all_online_cpus();
1421                 mutex_unlock(&trace_types_lock);
1422         }
1423
1424         return ret;
1425 }
1426 EXPORT_SYMBOL_GPL(synth_event_delete);
1427
1428 static int check_command(const char *raw_command)
1429 {
1430         char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1431         int argc, ret = 0;
1432
1433         cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1434         if (!cmd)
1435                 return -ENOMEM;
1436
1437         name_and_field = strsep(&cmd, ";");
1438         if (!name_and_field) {
1439                 ret = -EINVAL;
1440                 goto free;
1441         }
1442
1443         if (name_and_field[0] == '!')
1444                 goto free;
1445
1446         argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1447         if (!argv) {
1448                 ret = -ENOMEM;
1449                 goto free;
1450         }
1451         argv_free(argv);
1452
1453         if (argc < 3)
1454                 ret = -EINVAL;
1455 free:
1456         kfree(saved_cmd);
1457
1458         return ret;
1459 }
1460
1461 static int create_or_delete_synth_event(const char *raw_command)
1462 {
1463         char *name = NULL, *fields, *p;
1464         int ret = 0;
1465
1466         raw_command = skip_spaces(raw_command);
1467         if (raw_command[0] == '\0')
1468                 return ret;
1469
1470         last_cmd_set(raw_command);
1471
1472         ret = check_command(raw_command);
1473         if (ret) {
1474                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1475                 return ret;
1476         }
1477
1478         p = strpbrk(raw_command, " \t");
1479         if (!p && raw_command[0] != '!') {
1480                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1481                 ret = -EINVAL;
1482                 goto free;
1483         }
1484
1485         name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1486         if (!name)
1487                 return -ENOMEM;
1488
1489         if (name[0] == '!') {
1490                 ret = synth_event_delete(name + 1);
1491                 goto free;
1492         }
1493
1494         fields = skip_spaces(p);
1495
1496         ret = __create_synth_event(name, fields);
1497 free:
1498         kfree(name);
1499
1500         return ret;
1501 }
1502
1503 static int synth_event_run_command(struct dynevent_cmd *cmd)
1504 {
1505         struct synth_event *se;
1506         int ret;
1507
1508         ret = create_or_delete_synth_event(cmd->seq.buffer);
1509         if (ret)
1510                 return ret;
1511
1512         se = find_synth_event(cmd->event_name);
1513         if (WARN_ON(!se))
1514                 return -ENOENT;
1515
1516         se->mod = cmd->private_data;
1517
1518         return ret;
1519 }
1520
1521 /**
1522  * synth_event_cmd_init - Initialize a synthetic event command object
1523  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1524  * @buf: A pointer to the buffer used to build the command
1525  * @maxlen: The length of the buffer passed in @buf
1526  *
1527  * Initialize a synthetic event command object.  Use this before
1528  * calling any of the other dyenvent_cmd functions.
1529  */
1530 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1531 {
1532         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1533                           synth_event_run_command);
1534 }
1535 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1536
1537 static inline int
1538 __synth_event_trace_init(struct trace_event_file *file,
1539                          struct synth_event_trace_state *trace_state)
1540 {
1541         int ret = 0;
1542
1543         memset(trace_state, '\0', sizeof(*trace_state));
1544
1545         /*
1546          * Normal event tracing doesn't get called at all unless the
1547          * ENABLED bit is set (which attaches the probe thus allowing
1548          * this code to be called, etc).  Because this is called
1549          * directly by the user, we don't have that but we still need
1550          * to honor not logging when disabled.  For the iterated
1551          * trace case, we save the enabled state upon start and just
1552          * ignore the following data calls.
1553          */
1554         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1555             trace_trigger_soft_disabled(file)) {
1556                 trace_state->disabled = true;
1557                 ret = -ENOENT;
1558                 goto out;
1559         }
1560
1561         trace_state->event = file->event_call->data;
1562 out:
1563         return ret;
1564 }
1565
1566 static inline int
1567 __synth_event_trace_start(struct trace_event_file *file,
1568                           struct synth_event_trace_state *trace_state,
1569                           int dynamic_fields_size)
1570 {
1571         int entry_size, fields_size = 0;
1572         int ret = 0;
1573
1574         fields_size = trace_state->event->n_u64 * sizeof(u64);
1575         fields_size += dynamic_fields_size;
1576
1577         /*
1578          * Avoid ring buffer recursion detection, as this event
1579          * is being performed within another event.
1580          */
1581         trace_state->buffer = file->tr->array_buffer.buffer;
1582         ring_buffer_nest_start(trace_state->buffer);
1583
1584         entry_size = sizeof(*trace_state->entry) + fields_size;
1585         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1586                                                         file,
1587                                                         entry_size);
1588         if (!trace_state->entry) {
1589                 ring_buffer_nest_end(trace_state->buffer);
1590                 ret = -EINVAL;
1591         }
1592
1593         return ret;
1594 }
1595
1596 static inline void
1597 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1598 {
1599         trace_event_buffer_commit(&trace_state->fbuffer);
1600
1601         ring_buffer_nest_end(trace_state->buffer);
1602 }
1603
1604 /**
1605  * synth_event_trace - Trace a synthetic event
1606  * @file: The trace_event_file representing the synthetic event
1607  * @n_vals: The number of values in vals
1608  * @args: Variable number of args containing the event values
1609  *
1610  * Trace a synthetic event using the values passed in the variable
1611  * argument list.
1612  *
1613  * The argument list should be a list 'n_vals' u64 values.  The number
1614  * of vals must match the number of field in the synthetic event, and
1615  * must be in the same order as the synthetic event fields.
1616  *
1617  * All vals should be cast to u64, and string vals are just pointers
1618  * to strings, cast to u64.  Strings will be copied into space
1619  * reserved in the event for the string, using these pointers.
1620  *
1621  * Return: 0 on success, err otherwise.
1622  */
1623 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1624 {
1625         unsigned int i, n_u64, len, data_size = 0;
1626         struct synth_event_trace_state state;
1627         va_list args;
1628         int ret;
1629
1630         ret = __synth_event_trace_init(file, &state);
1631         if (ret) {
1632                 if (ret == -ENOENT)
1633                         ret = 0; /* just disabled, not really an error */
1634                 return ret;
1635         }
1636
1637         if (state.event->n_dynamic_fields) {
1638                 va_start(args, n_vals);
1639
1640                 for (i = 0; i < state.event->n_fields; i++) {
1641                         u64 val = va_arg(args, u64);
1642
1643                         if (state.event->fields[i]->is_string &&
1644                             state.event->fields[i]->is_dynamic) {
1645                                 char *str_val = (char *)(long)val;
1646
1647                                 data_size += strlen(str_val) + 1;
1648                         }
1649                 }
1650
1651                 va_end(args);
1652         }
1653
1654         ret = __synth_event_trace_start(file, &state, data_size);
1655         if (ret)
1656                 return ret;
1657
1658         if (n_vals != state.event->n_fields) {
1659                 ret = -EINVAL;
1660                 goto out;
1661         }
1662
1663         data_size = 0;
1664
1665         va_start(args, n_vals);
1666         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1667                 u64 val;
1668
1669                 val = va_arg(args, u64);
1670
1671                 if (state.event->fields[i]->is_string) {
1672                         char *str_val = (char *)(long)val;
1673
1674                         len = trace_string(state.entry, state.event, str_val,
1675                                            state.event->fields[i]->is_dynamic,
1676                                            data_size, &n_u64);
1677                         data_size += len; /* only dynamic string increments */
1678                 } else {
1679                         struct synth_field *field = state.event->fields[i];
1680
1681                         switch (field->size) {
1682                         case 1:
1683                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1684                                 break;
1685
1686                         case 2:
1687                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1688                                 break;
1689
1690                         case 4:
1691                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1692                                 break;
1693
1694                         default:
1695                                 state.entry->fields[n_u64] = val;
1696                                 break;
1697                         }
1698                         n_u64++;
1699                 }
1700         }
1701         va_end(args);
1702 out:
1703         __synth_event_trace_end(&state);
1704
1705         return ret;
1706 }
1707 EXPORT_SYMBOL_GPL(synth_event_trace);
1708
1709 /**
1710  * synth_event_trace_array - Trace a synthetic event from an array
1711  * @file: The trace_event_file representing the synthetic event
1712  * @vals: Array of values
1713  * @n_vals: The number of values in vals
1714  *
1715  * Trace a synthetic event using the values passed in as 'vals'.
1716  *
1717  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1718  * vals must match the number of field in the synthetic event, and
1719  * must be in the same order as the synthetic event fields.
1720  *
1721  * All vals should be cast to u64, and string vals are just pointers
1722  * to strings, cast to u64.  Strings will be copied into space
1723  * reserved in the event for the string, using these pointers.
1724  *
1725  * Return: 0 on success, err otherwise.
1726  */
1727 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1728                             unsigned int n_vals)
1729 {
1730         unsigned int i, n_u64, field_pos, len, data_size = 0;
1731         struct synth_event_trace_state state;
1732         char *str_val;
1733         int ret;
1734
1735         ret = __synth_event_trace_init(file, &state);
1736         if (ret) {
1737                 if (ret == -ENOENT)
1738                         ret = 0; /* just disabled, not really an error */
1739                 return ret;
1740         }
1741
1742         if (state.event->n_dynamic_fields) {
1743                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1744                         field_pos = state.event->dynamic_fields[i]->field_pos;
1745                         str_val = (char *)(long)vals[field_pos];
1746                         len = strlen(str_val) + 1;
1747                         data_size += len;
1748                 }
1749         }
1750
1751         ret = __synth_event_trace_start(file, &state, data_size);
1752         if (ret)
1753                 return ret;
1754
1755         if (n_vals != state.event->n_fields) {
1756                 ret = -EINVAL;
1757                 goto out;
1758         }
1759
1760         data_size = 0;
1761
1762         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1763                 if (state.event->fields[i]->is_string) {
1764                         char *str_val = (char *)(long)vals[i];
1765
1766                         len = trace_string(state.entry, state.event, str_val,
1767                                            state.event->fields[i]->is_dynamic,
1768                                            data_size, &n_u64);
1769                         data_size += len; /* only dynamic string increments */
1770                 } else {
1771                         struct synth_field *field = state.event->fields[i];
1772                         u64 val = vals[i];
1773
1774                         switch (field->size) {
1775                         case 1:
1776                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1777                                 break;
1778
1779                         case 2:
1780                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1781                                 break;
1782
1783                         case 4:
1784                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1785                                 break;
1786
1787                         default:
1788                                 state.entry->fields[n_u64] = val;
1789                                 break;
1790                         }
1791                         n_u64++;
1792                 }
1793         }
1794 out:
1795         __synth_event_trace_end(&state);
1796
1797         return ret;
1798 }
1799 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1800
1801 /**
1802  * synth_event_trace_start - Start piecewise synthetic event trace
1803  * @file: The trace_event_file representing the synthetic event
1804  * @trace_state: A pointer to object tracking the piecewise trace state
1805  *
1806  * Start the trace of a synthetic event field-by-field rather than all
1807  * at once.
1808  *
1809  * This function 'opens' an event trace, which means space is reserved
1810  * for the event in the trace buffer, after which the event's
1811  * individual field values can be set through either
1812  * synth_event_add_next_val() or synth_event_add_val().
1813  *
1814  * A pointer to a trace_state object is passed in, which will keep
1815  * track of the current event trace state until the event trace is
1816  * closed (and the event finally traced) using
1817  * synth_event_trace_end().
1818  *
1819  * Note that synth_event_trace_end() must be called after all values
1820  * have been added for each event trace, regardless of whether adding
1821  * all field values succeeded or not.
1822  *
1823  * Note also that for a given event trace, all fields must be added
1824  * using either synth_event_add_next_val() or synth_event_add_val()
1825  * but not both together or interleaved.
1826  *
1827  * Return: 0 on success, err otherwise.
1828  */
1829 int synth_event_trace_start(struct trace_event_file *file,
1830                             struct synth_event_trace_state *trace_state)
1831 {
1832         int ret;
1833
1834         if (!trace_state)
1835                 return -EINVAL;
1836
1837         ret = __synth_event_trace_init(file, trace_state);
1838         if (ret) {
1839                 if (ret == -ENOENT)
1840                         ret = 0; /* just disabled, not really an error */
1841                 return ret;
1842         }
1843
1844         if (trace_state->event->n_dynamic_fields)
1845                 return -ENOTSUPP;
1846
1847         ret = __synth_event_trace_start(file, trace_state, 0);
1848
1849         return ret;
1850 }
1851 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1852
1853 static int __synth_event_add_val(const char *field_name, u64 val,
1854                                  struct synth_event_trace_state *trace_state)
1855 {
1856         struct synth_field *field = NULL;
1857         struct synth_trace_event *entry;
1858         struct synth_event *event;
1859         int i, ret = 0;
1860
1861         if (!trace_state) {
1862                 ret = -EINVAL;
1863                 goto out;
1864         }
1865
1866         /* can't mix add_next_synth_val() with add_synth_val() */
1867         if (field_name) {
1868                 if (trace_state->add_next) {
1869                         ret = -EINVAL;
1870                         goto out;
1871                 }
1872                 trace_state->add_name = true;
1873         } else {
1874                 if (trace_state->add_name) {
1875                         ret = -EINVAL;
1876                         goto out;
1877                 }
1878                 trace_state->add_next = true;
1879         }
1880
1881         if (trace_state->disabled)
1882                 goto out;
1883
1884         event = trace_state->event;
1885         if (trace_state->add_name) {
1886                 for (i = 0; i < event->n_fields; i++) {
1887                         field = event->fields[i];
1888                         if (strcmp(field->name, field_name) == 0)
1889                                 break;
1890                 }
1891                 if (!field) {
1892                         ret = -EINVAL;
1893                         goto out;
1894                 }
1895         } else {
1896                 if (trace_state->cur_field >= event->n_fields) {
1897                         ret = -EINVAL;
1898                         goto out;
1899                 }
1900                 field = event->fields[trace_state->cur_field++];
1901         }
1902
1903         entry = trace_state->entry;
1904         if (field->is_string) {
1905                 char *str_val = (char *)(long)val;
1906                 char *str_field;
1907
1908                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
1909                         ret = -EINVAL;
1910                         goto out;
1911                 }
1912
1913                 if (!str_val) {
1914                         ret = -EINVAL;
1915                         goto out;
1916                 }
1917
1918                 str_field = (char *)&entry->fields[field->offset];
1919                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
1920         } else {
1921                 switch (field->size) {
1922                 case 1:
1923                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
1924                         break;
1925
1926                 case 2:
1927                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
1928                         break;
1929
1930                 case 4:
1931                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
1932                         break;
1933
1934                 default:
1935                         trace_state->entry->fields[field->offset] = val;
1936                         break;
1937                 }
1938         }
1939  out:
1940         return ret;
1941 }
1942
1943 /**
1944  * synth_event_add_next_val - Add the next field's value to an open synth trace
1945  * @val: The value to set the next field to
1946  * @trace_state: A pointer to object tracking the piecewise trace state
1947  *
1948  * Set the value of the next field in an event that's been opened by
1949  * synth_event_trace_start().
1950  *
1951  * The val param should be the value cast to u64.  If the value points
1952  * to a string, the val param should be a char * cast to u64.
1953  *
1954  * This function assumes all the fields in an event are to be set one
1955  * after another - successive calls to this function are made, one for
1956  * each field, in the order of the fields in the event, until all
1957  * fields have been set.  If you'd rather set each field individually
1958  * without regard to ordering, synth_event_add_val() can be used
1959  * instead.
1960  *
1961  * Note however that synth_event_add_next_val() and
1962  * synth_event_add_val() can't be intermixed for a given event trace -
1963  * one or the other but not both can be used at the same time.
1964  *
1965  * Note also that synth_event_trace_end() must be called after all
1966  * values have been added for each event trace, regardless of whether
1967  * adding all field values succeeded or not.
1968  *
1969  * Return: 0 on success, err otherwise.
1970  */
1971 int synth_event_add_next_val(u64 val,
1972                              struct synth_event_trace_state *trace_state)
1973 {
1974         return __synth_event_add_val(NULL, val, trace_state);
1975 }
1976 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
1977
1978 /**
1979  * synth_event_add_val - Add a named field's value to an open synth trace
1980  * @field_name: The name of the synthetic event field value to set
1981  * @val: The value to set the next field to
1982  * @trace_state: A pointer to object tracking the piecewise trace state
1983  *
1984  * Set the value of the named field in an event that's been opened by
1985  * synth_event_trace_start().
1986  *
1987  * The val param should be the value cast to u64.  If the value points
1988  * to a string, the val param should be a char * cast to u64.
1989  *
1990  * This function looks up the field name, and if found, sets the field
1991  * to the specified value.  This lookup makes this function more
1992  * expensive than synth_event_add_next_val(), so use that or the
1993  * none-piecewise synth_event_trace() instead if efficiency is more
1994  * important.
1995  *
1996  * Note however that synth_event_add_next_val() and
1997  * synth_event_add_val() can't be intermixed for a given event trace -
1998  * one or the other but not both can be used at the same time.
1999  *
2000  * Note also that synth_event_trace_end() must be called after all
2001  * values have been added for each event trace, regardless of whether
2002  * adding all field values succeeded or not.
2003  *
2004  * Return: 0 on success, err otherwise.
2005  */
2006 int synth_event_add_val(const char *field_name, u64 val,
2007                         struct synth_event_trace_state *trace_state)
2008 {
2009         return __synth_event_add_val(field_name, val, trace_state);
2010 }
2011 EXPORT_SYMBOL_GPL(synth_event_add_val);
2012
2013 /**
2014  * synth_event_trace_end - End piecewise synthetic event trace
2015  * @trace_state: A pointer to object tracking the piecewise trace state
2016  *
2017  * End the trace of a synthetic event opened by
2018  * synth_event_trace__start().
2019  *
2020  * This function 'closes' an event trace, which basically means that
2021  * it commits the reserved event and cleans up other loose ends.
2022  *
2023  * A pointer to a trace_state object is passed in, which will keep
2024  * track of the current event trace state opened with
2025  * synth_event_trace_start().
2026  *
2027  * Note that this function must be called after all values have been
2028  * added for each event trace, regardless of whether adding all field
2029  * values succeeded or not.
2030  *
2031  * Return: 0 on success, err otherwise.
2032  */
2033 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2034 {
2035         if (!trace_state)
2036                 return -EINVAL;
2037
2038         __synth_event_trace_end(trace_state);
2039
2040         return 0;
2041 }
2042 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2043
2044 static int create_synth_event(const char *raw_command)
2045 {
2046         char *fields, *p;
2047         const char *name;
2048         int len, ret = 0;
2049
2050         raw_command = skip_spaces(raw_command);
2051         if (raw_command[0] == '\0')
2052                 return ret;
2053
2054         last_cmd_set(raw_command);
2055
2056         p = strpbrk(raw_command, " \t");
2057         if (!p) {
2058                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2059                 return -EINVAL;
2060         }
2061
2062         fields = skip_spaces(p);
2063
2064         name = raw_command;
2065
2066         if (name[0] != 's' || name[1] != ':')
2067                 return -ECANCELED;
2068         name += 2;
2069
2070         /* This interface accepts group name prefix */
2071         if (strchr(name, '/')) {
2072                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2073                 if (len == 0) {
2074                         synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2075                         return -EINVAL;
2076                 }
2077                 name += len;
2078         }
2079
2080         len = name - raw_command;
2081
2082         ret = check_command(raw_command + len);
2083         if (ret) {
2084                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2085                 return ret;
2086         }
2087
2088         name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2089         if (!name)
2090                 return -ENOMEM;
2091
2092         ret = __create_synth_event(name, fields);
2093
2094         kfree(name);
2095
2096         return ret;
2097 }
2098
2099 static int synth_event_release(struct dyn_event *ev)
2100 {
2101         struct synth_event *event = to_synth_event(ev);
2102         int ret;
2103
2104         if (event->ref)
2105                 return -EBUSY;
2106
2107         ret = unregister_synth_event(event);
2108         if (ret)
2109                 return ret;
2110
2111         dyn_event_remove(ev);
2112         free_synth_event(event);
2113         return 0;
2114 }
2115
2116 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2117 {
2118         struct synth_field *field;
2119         unsigned int i;
2120         char *type, *t;
2121
2122         seq_printf(m, "%s\t", event->name);
2123
2124         for (i = 0; i < event->n_fields; i++) {
2125                 field = event->fields[i];
2126
2127                 type = field->type;
2128                 t = strstr(type, "__data_loc");
2129                 if (t) { /* __data_loc belongs in format but not event desc */
2130                         t += sizeof("__data_loc");
2131                         type = t;
2132                 }
2133
2134                 /* parameter values */
2135                 seq_printf(m, "%s %s%s", type, field->name,
2136                            i == event->n_fields - 1 ? "" : "; ");
2137         }
2138
2139         seq_putc(m, '\n');
2140
2141         return 0;
2142 }
2143
2144 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2145 {
2146         struct synth_event *event = to_synth_event(ev);
2147
2148         seq_printf(m, "s:%s/", event->class.system);
2149
2150         return __synth_event_show(m, event);
2151 }
2152
2153 static int synth_events_seq_show(struct seq_file *m, void *v)
2154 {
2155         struct dyn_event *ev = v;
2156
2157         if (!is_synth_event(ev))
2158                 return 0;
2159
2160         return __synth_event_show(m, to_synth_event(ev));
2161 }
2162
2163 static const struct seq_operations synth_events_seq_op = {
2164         .start  = dyn_event_seq_start,
2165         .next   = dyn_event_seq_next,
2166         .stop   = dyn_event_seq_stop,
2167         .show   = synth_events_seq_show,
2168 };
2169
2170 static int synth_events_open(struct inode *inode, struct file *file)
2171 {
2172         int ret;
2173
2174         ret = security_locked_down(LOCKDOWN_TRACEFS);
2175         if (ret)
2176                 return ret;
2177
2178         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2179                 ret = dyn_events_release_all(&synth_event_ops);
2180                 if (ret < 0)
2181                         return ret;
2182         }
2183
2184         return seq_open(file, &synth_events_seq_op);
2185 }
2186
2187 static ssize_t synth_events_write(struct file *file,
2188                                   const char __user *buffer,
2189                                   size_t count, loff_t *ppos)
2190 {
2191         return trace_parse_run_command(file, buffer, count, ppos,
2192                                        create_or_delete_synth_event);
2193 }
2194
2195 static const struct file_operations synth_events_fops = {
2196         .open           = synth_events_open,
2197         .write          = synth_events_write,
2198         .read           = seq_read,
2199         .llseek         = seq_lseek,
2200         .release        = seq_release,
2201 };
2202
2203 /*
2204  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2205  * events in postcore_initcall without tracefs.
2206  */
2207 static __init int trace_events_synth_init_early(void)
2208 {
2209         int err = 0;
2210
2211         err = dyn_event_register(&synth_event_ops);
2212         if (err)
2213                 pr_warn("Could not register synth_event_ops\n");
2214
2215         return err;
2216 }
2217 core_initcall(trace_events_synth_init_early);
2218
2219 static __init int trace_events_synth_init(void)
2220 {
2221         struct dentry *entry = NULL;
2222         int err = 0;
2223         err = tracing_init_dentry();
2224         if (err)
2225                 goto err;
2226
2227         entry = tracefs_create_file("synthetic_events", 0644, NULL,
2228                                     NULL, &synth_events_fops);
2229         if (!entry) {
2230                 err = -ENODEV;
2231                 goto err;
2232         }
2233
2234         return err;
2235  err:
2236         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2237
2238         return err;
2239 }
2240
2241 fs_initcall(trace_events_synth_init);