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 <tom.zanussi@linux.intel.com>
   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                 fields[i]->field_pos = i;
 897                 event->fields[i] = fields[i];
 898
 899                 if (fields[i]->is_dynamic)
 900                         event->dynamic_fields[j++] = fields[i];
 901         }
 902         event->n_dynamic_fields = j;
 903         event->n_fields = n_fields;
 904  out:
 905         return event;
 906 }
 907
 908 static int synth_event_check_arg_fn(void *data)
 909 {
 910         struct dynevent_arg_pair *arg_pair = data;
 911         int size;
 912
 913         size = synth_field_size((char *)arg_pair->lhs);
 914         if (size == 0) {
 915                 if (strstr((char *)arg_pair->lhs, "["))
 916                         return 0;
 917         }
 918
 919         return size ? 0 : -EINVAL;
 920 }
 921
 922 /**
 923  * synth_event_add_field - Add a new field to a synthetic event cmd
 924  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 925  * @type: The type of the new field to add
 926  * @name: The name of the new field to add
 927  *
 928  * Add a new field to a synthetic event cmd object.  Field ordering is in
 929  * the same order the fields are added.
 930  *
 931  * See synth_field_size() for available types. If field_name contains
 932  * [n] the field is considered to be an array.
 933  *
 934  * Return: 0 if successful, error otherwise.
 935  */
 936 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
 937                           const char *name)
 938 {
 939         struct dynevent_arg_pair arg_pair;
 940         int ret;
 941
 942         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 943                 return -EINVAL;
 944
 945         if (!type || !name)
 946                 return -EINVAL;
 947
 948         dynevent_arg_pair_init(&arg_pair, 0, ';');
 949
 950         arg_pair.lhs = type;
 951         arg_pair.rhs = name;
 952
 953         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
 954         if (ret)
 955                 return ret;
 956
 957         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 958                 ret = -EINVAL;
 959
 960         return ret;
 961 }
 962 EXPORT_SYMBOL_GPL(synth_event_add_field);
 963
 964 /**
 965  * synth_event_add_field_str - Add a new field to a synthetic event cmd
 966  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 967  * @type_name: The type and name of the new field to add, as a single string
 968  *
 969  * Add a new field to a synthetic event cmd object, as a single
 970  * string.  The @type_name string is expected to be of the form 'type
 971  * name', which will be appended by ';'.  No sanity checking is done -
 972  * what's passed in is assumed to already be well-formed.  Field
 973  * ordering is in the same order the fields are added.
 974  *
 975  * See synth_field_size() for available types. If field_name contains
 976  * [n] the field is considered to be an array.
 977  *
 978  * Return: 0 if successful, error otherwise.
 979  */
 980 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
 981 {
 982         struct dynevent_arg arg;
 983         int ret;
 984
 985         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 986                 return -EINVAL;
 987
 988         if (!type_name)
 989                 return -EINVAL;
 990
 991         dynevent_arg_init(&arg, ';');
 992
 993         arg.str = type_name;
 994
 995         ret = dynevent_arg_add(cmd, &arg, NULL);
 996         if (ret)
 997                 return ret;
 998
 999         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1000                 ret = -EINVAL;
1001
1002         return ret;
1003 }
1004 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1005
1006 /**
1007  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1008  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1009  * @fields: An array of type/name field descriptions
1010  * @n_fields: The number of field descriptions contained in the fields array
1011  *
1012  * Add a new set of fields to a synthetic event cmd object.  The event
1013  * fields that will be defined for the event should be passed in as an
1014  * array of struct synth_field_desc, and the number of elements in the
1015  * array passed in as n_fields.  Field ordering will retain the
1016  * ordering given in the fields array.
1017  *
1018  * See synth_field_size() for available types. If field_name contains
1019  * [n] the field is considered to be an array.
1020  *
1021  * Return: 0 if successful, error otherwise.
1022  */
1023 int synth_event_add_fields(struct dynevent_cmd *cmd,
1024                            struct synth_field_desc *fields,
1025                            unsigned int n_fields)
1026 {
1027         unsigned int i;
1028         int ret = 0;
1029
1030         for (i = 0; i < n_fields; i++) {
1031                 if (fields[i].type == NULL || fields[i].name == NULL) {
1032                         ret = -EINVAL;
1033                         break;
1034                 }
1035
1036                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1037                 if (ret)
1038                         break;
1039         }
1040
1041         return ret;
1042 }
1043 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1044
1045 /**
1046  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1047  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1048  * @name: The name of the synthetic event
1049  * @mod: The module creating the event, NULL if not created from a module
1050  * @args: Variable number of arg (pairs), one pair for each field
1051  *
1052  * NOTE: Users normally won't want to call this function directly, but
1053  * rather use the synth_event_gen_cmd_start() wrapper, which
1054  * automatically adds a NULL to the end of the arg list.  If this
1055  * function is used directly, make sure the last arg in the variable
1056  * arg list is NULL.
1057  *
1058  * Generate a synthetic event command to be executed by
1059  * synth_event_gen_cmd_end().  This function can be used to generate
1060  * the complete command or only the first part of it; in the latter
1061  * case, synth_event_add_field(), synth_event_add_field_str(), or
1062  * synth_event_add_fields() can be used to add more fields following
1063  * this.
1064  *
1065  * There should be an even number variable args, each pair consisting
1066  * of a type followed by a field name.
1067  *
1068  * See synth_field_size() for available types. If field_name contains
1069  * [n] the field is considered to be an array.
1070  *
1071  * Return: 0 if successful, error otherwise.
1072  */
1073 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1074                                 struct module *mod, ...)
1075 {
1076         struct dynevent_arg arg;
1077         va_list args;
1078         int ret;
1079
1080         cmd->event_name = name;
1081         cmd->private_data = mod;
1082
1083         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1084                 return -EINVAL;
1085
1086         dynevent_arg_init(&arg, 0);
1087         arg.str = name;
1088         ret = dynevent_arg_add(cmd, &arg, NULL);
1089         if (ret)
1090                 return ret;
1091
1092         va_start(args, mod);
1093         for (;;) {
1094                 const char *type, *name;
1095
1096                 type = va_arg(args, const char *);
1097                 if (!type)
1098                         break;
1099                 name = va_arg(args, const char *);
1100                 if (!name)
1101                         break;
1102
1103                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1104                         ret = -EINVAL;
1105                         break;
1106                 }
1107
1108                 ret = synth_event_add_field(cmd, type, name);
1109                 if (ret)
1110                         break;
1111         }
1112         va_end(args);
1113
1114         return ret;
1115 }
1116 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1117
1118 /**
1119  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1120  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1121  * @name: The name of the synthetic event
1122  * @fields: An array of type/name field descriptions
1123  * @n_fields: The number of field descriptions contained in the fields array
1124  *
1125  * Generate a synthetic event command to be executed by
1126  * synth_event_gen_cmd_end().  This function can be used to generate
1127  * the complete command or only the first part of it; in the latter
1128  * case, synth_event_add_field(), synth_event_add_field_str(), or
1129  * synth_event_add_fields() can be used to add more fields following
1130  * this.
1131  *
1132  * The event fields that will be defined for the event should be
1133  * passed in as an array of struct synth_field_desc, and the number of
1134  * elements in the array passed in as n_fields.  Field ordering will
1135  * retain the ordering given in the fields array.
1136  *
1137  * See synth_field_size() for available types. If field_name contains
1138  * [n] the field is considered to be an array.
1139  *
1140  * Return: 0 if successful, error otherwise.
1141  */
1142 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1143                                     struct module *mod,
1144                                     struct synth_field_desc *fields,
1145                                     unsigned int n_fields)
1146 {
1147         struct dynevent_arg arg;
1148         unsigned int i;
1149         int ret = 0;
1150
1151         cmd->event_name = name;
1152         cmd->private_data = mod;
1153
1154         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1155                 return -EINVAL;
1156
1157         if (n_fields > SYNTH_FIELDS_MAX)
1158                 return -EINVAL;
1159
1160         dynevent_arg_init(&arg, 0);
1161         arg.str = name;
1162         ret = dynevent_arg_add(cmd, &arg, NULL);
1163         if (ret)
1164                 return ret;
1165
1166         for (i = 0; i < n_fields; i++) {
1167                 if (fields[i].type == NULL || fields[i].name == NULL)
1168                         return -EINVAL;
1169
1170                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1171                 if (ret)
1172                         break;
1173         }
1174
1175         return ret;
1176 }
1177 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1178
1179 static int __create_synth_event(const char *name, const char *raw_fields)
1180 {
1181         char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1182         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1183         int consumed, cmd_version = 1, n_fields_this_loop;
1184         int i, argc, n_fields = 0, ret = 0;
1185         struct synth_event *event = NULL;
1186
1187         /*
1188          * Argument syntax:
1189          *  - Add synthetic event: <event_name> field[;field] ...
1190          *  - Remove synthetic event: !<event_name> field[;field] ...
1191          *      where 'field' = type field_name
1192          */
1193
1194         if (name[0] == '\0') {
1195                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1196                 return -EINVAL;
1197         }
1198
1199         if (!is_good_name(name)) {
1200                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1201                 return -EINVAL;
1202         }
1203
1204         mutex_lock(&event_mutex);
1205
1206         event = find_synth_event(name);
1207         if (event) {
1208                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1209                 ret = -EEXIST;
1210                 goto err;
1211         }
1212
1213         tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1214         if (!tmp_fields) {
1215                 ret = -ENOMEM;
1216                 goto err;
1217         }
1218
1219         while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1220                 argv = argv_split(GFP_KERNEL, field_str, &argc);
1221                 if (!argv) {
1222                         ret = -ENOMEM;
1223                         goto err;
1224                 }
1225
1226                 if (!argc) {
1227                         argv_free(argv);
1228                         continue;
1229                 }
1230
1231                 n_fields_this_loop = 0;
1232                 consumed = 0;
1233                 while (argc > consumed) {
1234                         int field_version;
1235
1236                         field = parse_synth_field(argc - consumed,
1237                                                   argv + consumed, &consumed,
1238                                                   &field_version);
1239                         if (IS_ERR(field)) {
1240                                 ret = PTR_ERR(field);
1241                                 goto err_free_arg;
1242                         }
1243
1244                         /*
1245                          * Track the highest version of any field we
1246                          * found in the command.
1247                          */
1248                         if (field_version > cmd_version)
1249                                 cmd_version = field_version;
1250
1251                         /*
1252                          * Now sort out what is and isn't valid for
1253                          * each supported version.
1254                          *
1255                          * If we see more than 1 field per loop, it
1256                          * means we have multiple fields between
1257                          * semicolons, and that's something we no
1258                          * longer support in a version 2 or greater
1259                          * command.
1260                          */
1261                         if (cmd_version > 1 && n_fields_this_loop >= 1) {
1262                                 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1263                                 ret = -EINVAL;
1264                                 goto err_free_arg;
1265                         }
1266
1267                         fields[n_fields++] = field;
1268                         if (n_fields == SYNTH_FIELDS_MAX) {
1269                                 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1270                                 ret = -EINVAL;
1271                                 goto err_free_arg;
1272                         }
1273
1274                         n_fields_this_loop++;
1275                 }
1276                 argv_free(argv);
1277
1278                 if (consumed < argc) {
1279                         synth_err(SYNTH_ERR_INVALID_CMD, 0);
1280                         ret = -EINVAL;
1281                         goto err;
1282                 }
1283
1284         }
1285
1286         if (n_fields == 0) {
1287                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1288                 ret = -EINVAL;
1289                 goto err;
1290         }
1291
1292         event = alloc_synth_event(name, n_fields, fields);
1293         if (IS_ERR(event)) {
1294                 ret = PTR_ERR(event);
1295                 event = NULL;
1296                 goto err;
1297         }
1298         ret = register_synth_event(event);
1299         if (!ret)
1300                 dyn_event_add(&event->devent, &event->call);
1301         else
1302                 free_synth_event(event);
1303  out:
1304         mutex_unlock(&event_mutex);
1305
1306         kfree(saved_fields);
1307
1308         return ret;
1309  err_free_arg:
1310         argv_free(argv);
1311  err:
1312         for (i = 0; i < n_fields; i++)
1313                 free_synth_field(fields[i]);
1314
1315         goto out;
1316 }
1317
1318 /**
1319  * synth_event_create - Create a new synthetic event
1320  * @name: The name of the new synthetic event
1321  * @fields: An array of type/name field descriptions
1322  * @n_fields: The number of field descriptions contained in the fields array
1323  * @mod: The module creating the event, NULL if not created from a module
1324  *
1325  * Create a new synthetic event with the given name under the
1326  * trace/events/synthetic/ directory.  The event fields that will be
1327  * defined for the event should be passed in as an array of struct
1328  * synth_field_desc, and the number elements in the array passed in as
1329  * n_fields. Field ordering will retain the ordering given in the
1330  * fields array.
1331  *
1332  * If the new synthetic event is being created from a module, the mod
1333  * param must be non-NULL.  This will ensure that the trace buffer
1334  * won't contain unreadable events.
1335  *
1336  * The new synth event should be deleted using synth_event_delete()
1337  * function.  The new synthetic event can be generated from modules or
1338  * other kernel code using trace_synth_event() and related functions.
1339  *
1340  * Return: 0 if successful, error otherwise.
1341  */
1342 int synth_event_create(const char *name, struct synth_field_desc *fields,
1343                        unsigned int n_fields, struct module *mod)
1344 {
1345         struct dynevent_cmd cmd;
1346         char *buf;
1347         int ret;
1348
1349         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1350         if (!buf)
1351                 return -ENOMEM;
1352
1353         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1354
1355         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1356                                               fields, n_fields);
1357         if (ret)
1358                 goto out;
1359
1360         ret = synth_event_gen_cmd_end(&cmd);
1361  out:
1362         kfree(buf);
1363
1364         return ret;
1365 }
1366 EXPORT_SYMBOL_GPL(synth_event_create);
1367
1368 static int destroy_synth_event(struct synth_event *se)
1369 {
1370         int ret;
1371
1372         if (se->ref)
1373                 return -EBUSY;
1374
1375         if (trace_event_dyn_busy(&se->call))
1376                 return -EBUSY;
1377
1378         ret = unregister_synth_event(se);
1379         if (!ret) {
1380                 dyn_event_remove(&se->devent);
1381                 free_synth_event(se);
1382         }
1383
1384         return ret;
1385 }
1386
1387 /**
1388  * synth_event_delete - Delete a synthetic event
1389  * @event_name: The name of the new synthetic event
1390  *
1391  * Delete a synthetic event that was created with synth_event_create().
1392  *
1393  * Return: 0 if successful, error otherwise.
1394  */
1395 int synth_event_delete(const char *event_name)
1396 {
1397         struct synth_event *se = NULL;
1398         struct module *mod = NULL;
1399         int ret = -ENOENT;
1400
1401         mutex_lock(&event_mutex);
1402         se = find_synth_event(event_name);
1403         if (se) {
1404                 mod = se->mod;
1405                 ret = destroy_synth_event(se);
1406         }
1407         mutex_unlock(&event_mutex);
1408
1409         if (mod) {
1410                 mutex_lock(&trace_types_lock);
1411                 /*
1412                  * It is safest to reset the ring buffer if the module
1413                  * being unloaded registered any events that were
1414                  * used. The only worry is if a new module gets
1415                  * loaded, and takes on the same id as the events of
1416                  * this module. When printing out the buffer, traced
1417                  * events left over from this module may be passed to
1418                  * the new module events and unexpected results may
1419                  * occur.
1420                  */
1421                 tracing_reset_all_online_cpus();
1422                 mutex_unlock(&trace_types_lock);
1423         }
1424
1425         return ret;
1426 }
1427 EXPORT_SYMBOL_GPL(synth_event_delete);
1428
1429 static int check_command(const char *raw_command)
1430 {
1431         char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1432         int argc, ret = 0;
1433
1434         cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1435         if (!cmd)
1436                 return -ENOMEM;
1437
1438         name_and_field = strsep(&cmd, ";");
1439         if (!name_and_field) {
1440                 ret = -EINVAL;
1441                 goto free;
1442         }
1443
1444         if (name_and_field[0] == '!')
1445                 goto free;
1446
1447         argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1448         if (!argv) {
1449                 ret = -ENOMEM;
1450                 goto free;
1451         }
1452         argv_free(argv);
1453
1454         if (argc < 3)
1455                 ret = -EINVAL;
1456 free:
1457         kfree(saved_cmd);
1458
1459         return ret;
1460 }
1461
1462 static int create_or_delete_synth_event(const char *raw_command)
1463 {
1464         char *name = NULL, *fields, *p;
1465         int ret = 0;
1466
1467         raw_command = skip_spaces(raw_command);
1468         if (raw_command[0] == '\0')
1469                 return ret;
1470
1471         last_cmd_set(raw_command);
1472
1473         ret = check_command(raw_command);
1474         if (ret) {
1475                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1476                 return ret;
1477         }
1478
1479         p = strpbrk(raw_command, " \t");
1480         if (!p && raw_command[0] != '!') {
1481                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1482                 ret = -EINVAL;
1483                 goto free;
1484         }
1485
1486         name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1487         if (!name)
1488                 return -ENOMEM;
1489
1490         if (name[0] == '!') {
1491                 ret = synth_event_delete(name + 1);
1492                 goto free;
1493         }
1494
1495         fields = skip_spaces(p);
1496
1497         ret = __create_synth_event(name, fields);
1498 free:
1499         kfree(name);
1500
1501         return ret;
1502 }
1503
1504 static int synth_event_run_command(struct dynevent_cmd *cmd)
1505 {
1506         struct synth_event *se;
1507         int ret;
1508
1509         ret = create_or_delete_synth_event(cmd->seq.buffer);
1510         if (ret)
1511                 return ret;
1512
1513         se = find_synth_event(cmd->event_name);
1514         if (WARN_ON(!se))
1515                 return -ENOENT;
1516
1517         se->mod = cmd->private_data;
1518
1519         return ret;
1520 }
1521
1522 /**
1523  * synth_event_cmd_init - Initialize a synthetic event command object
1524  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1525  * @buf: A pointer to the buffer used to build the command
1526  * @maxlen: The length of the buffer passed in @buf
1527  *
1528  * Initialize a synthetic event command object.  Use this before
1529  * calling any of the other dyenvent_cmd functions.
1530  */
1531 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1532 {
1533         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1534                           synth_event_run_command);
1535 }
1536 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1537
1538 static inline int
1539 __synth_event_trace_init(struct trace_event_file *file,
1540                          struct synth_event_trace_state *trace_state)
1541 {
1542         int ret = 0;
1543
1544         memset(trace_state, '\0', sizeof(*trace_state));
1545
1546         /*
1547          * Normal event tracing doesn't get called at all unless the
1548          * ENABLED bit is set (which attaches the probe thus allowing
1549          * this code to be called, etc).  Because this is called
1550          * directly by the user, we don't have that but we still need
1551          * to honor not logging when disabled.  For the iterated
1552          * trace case, we save the enabled state upon start and just
1553          * ignore the following data calls.
1554          */
1555         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1556             trace_trigger_soft_disabled(file)) {
1557                 trace_state->disabled = true;
1558                 ret = -ENOENT;
1559                 goto out;
1560         }
1561
1562         trace_state->event = file->event_call->data;
1563 out:
1564         return ret;
1565 }
1566
1567 static inline int
1568 __synth_event_trace_start(struct trace_event_file *file,
1569                           struct synth_event_trace_state *trace_state,
1570                           int dynamic_fields_size)
1571 {
1572         int entry_size, fields_size = 0;
1573         int ret = 0;
1574
1575         fields_size = trace_state->event->n_u64 * sizeof(u64);
1576         fields_size += dynamic_fields_size;
1577
1578         /*
1579          * Avoid ring buffer recursion detection, as this event
1580          * is being performed within another event.
1581          */
1582         trace_state->buffer = file->tr->array_buffer.buffer;
1583         ring_buffer_nest_start(trace_state->buffer);
1584
1585         entry_size = sizeof(*trace_state->entry) + fields_size;
1586         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1587                                                         file,
1588                                                         entry_size);
1589         if (!trace_state->entry) {
1590                 ring_buffer_nest_end(trace_state->buffer);
1591                 ret = -EINVAL;
1592         }
1593
1594         return ret;
1595 }
1596
1597 static inline void
1598 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1599 {
1600         trace_event_buffer_commit(&trace_state->fbuffer);
1601
1602         ring_buffer_nest_end(trace_state->buffer);
1603 }
1604
1605 /**
1606  * synth_event_trace - Trace a synthetic event
1607  * @file: The trace_event_file representing the synthetic event
1608  * @n_vals: The number of values in vals
1609  * @args: Variable number of args containing the event values
1610  *
1611  * Trace a synthetic event using the values passed in the variable
1612  * argument list.
1613  *
1614  * The argument list should be a list 'n_vals' u64 values.  The number
1615  * of vals must match the number of field in the synthetic event, and
1616  * must be in the same order as the synthetic event fields.
1617  *
1618  * All vals should be cast to u64, and string vals are just pointers
1619  * to strings, cast to u64.  Strings will be copied into space
1620  * reserved in the event for the string, using these pointers.
1621  *
1622  * Return: 0 on success, err otherwise.
1623  */
1624 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1625 {
1626         unsigned int i, n_u64, len, data_size = 0;
1627         struct synth_event_trace_state state;
1628         va_list args;
1629         int ret;
1630
1631         ret = __synth_event_trace_init(file, &state);
1632         if (ret) {
1633                 if (ret == -ENOENT)
1634                         ret = 0; /* just disabled, not really an error */
1635                 return ret;
1636         }
1637
1638         if (state.event->n_dynamic_fields) {
1639                 va_start(args, n_vals);
1640
1641                 for (i = 0; i < state.event->n_fields; i++) {
1642                         u64 val = va_arg(args, u64);
1643
1644                         if (state.event->fields[i]->is_string &&
1645                             state.event->fields[i]->is_dynamic) {
1646                                 char *str_val = (char *)(long)val;
1647
1648                                 data_size += strlen(str_val) + 1;
1649                         }
1650                 }
1651
1652                 va_end(args);
1653         }
1654
1655         ret = __synth_event_trace_start(file, &state, data_size);
1656         if (ret)
1657                 return ret;
1658
1659         if (n_vals != state.event->n_fields) {
1660                 ret = -EINVAL;
1661                 goto out;
1662         }
1663
1664         data_size = 0;
1665
1666         va_start(args, n_vals);
1667         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1668                 u64 val;
1669
1670                 val = va_arg(args, u64);
1671
1672                 if (state.event->fields[i]->is_string) {
1673                         char *str_val = (char *)(long)val;
1674
1675                         len = trace_string(state.entry, state.event, str_val,
1676                                            state.event->fields[i]->is_dynamic,
1677                                            data_size, &n_u64);
1678                         data_size += len; /* only dynamic string increments */
1679                 } else {
1680                         struct synth_field *field = state.event->fields[i];
1681
1682                         switch (field->size) {
1683                         case 1:
1684                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1685                                 break;
1686
1687                         case 2:
1688                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1689                                 break;
1690
1691                         case 4:
1692                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1693                                 break;
1694
1695                         default:
1696                                 state.entry->fields[n_u64] = val;
1697                                 break;
1698                         }
1699                         n_u64++;
1700                 }
1701         }
1702         va_end(args);
1703 out:
1704         __synth_event_trace_end(&state);
1705
1706         return ret;
1707 }
1708 EXPORT_SYMBOL_GPL(synth_event_trace);
1709
1710 /**
1711  * synth_event_trace_array - Trace a synthetic event from an array
1712  * @file: The trace_event_file representing the synthetic event
1713  * @vals: Array of values
1714  * @n_vals: The number of values in vals
1715  *
1716  * Trace a synthetic event using the values passed in as 'vals'.
1717  *
1718  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1719  * vals must match the number of field in the synthetic event, and
1720  * must be in the same order as the synthetic event fields.
1721  *
1722  * All vals should be cast to u64, and string vals are just pointers
1723  * to strings, cast to u64.  Strings will be copied into space
1724  * reserved in the event for the string, using these pointers.
1725  *
1726  * Return: 0 on success, err otherwise.
1727  */
1728 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1729                             unsigned int n_vals)
1730 {
1731         unsigned int i, n_u64, field_pos, len, data_size = 0;
1732         struct synth_event_trace_state state;
1733         char *str_val;
1734         int ret;
1735
1736         ret = __synth_event_trace_init(file, &state);
1737         if (ret) {
1738                 if (ret == -ENOENT)
1739                         ret = 0; /* just disabled, not really an error */
1740                 return ret;
1741         }
1742
1743         if (state.event->n_dynamic_fields) {
1744                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1745                         field_pos = state.event->dynamic_fields[i]->field_pos;
1746                         str_val = (char *)(long)vals[field_pos];
1747                         len = strlen(str_val) + 1;
1748                         data_size += len;
1749                 }
1750         }
1751
1752         ret = __synth_event_trace_start(file, &state, data_size);
1753         if (ret)
1754                 return ret;
1755
1756         if (n_vals != state.event->n_fields) {
1757                 ret = -EINVAL;
1758                 goto out;
1759         }
1760
1761         data_size = 0;
1762
1763         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1764                 if (state.event->fields[i]->is_string) {
1765                         char *str_val = (char *)(long)vals[i];
1766
1767                         len = trace_string(state.entry, state.event, str_val,
1768                                            state.event->fields[i]->is_dynamic,
1769                                            data_size, &n_u64);
1770                         data_size += len; /* only dynamic string increments */
1771                 } else {
1772                         struct synth_field *field = state.event->fields[i];
1773                         u64 val = vals[i];
1774
1775                         switch (field->size) {
1776                         case 1:
1777                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1778                                 break;
1779
1780                         case 2:
1781                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1782                                 break;
1783
1784                         case 4:
1785                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1786                                 break;
1787
1788                         default:
1789                                 state.entry->fields[n_u64] = val;
1790                                 break;
1791                         }
1792                         n_u64++;
1793                 }
1794         }
1795 out:
1796         __synth_event_trace_end(&state);
1797
1798         return ret;
1799 }
1800 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1801
1802 /**
1803  * synth_event_trace_start - Start piecewise synthetic event trace
1804  * @file: The trace_event_file representing the synthetic event
1805  * @trace_state: A pointer to object tracking the piecewise trace state
1806  *
1807  * Start the trace of a synthetic event field-by-field rather than all
1808  * at once.
1809  *
1810  * This function 'opens' an event trace, which means space is reserved
1811  * for the event in the trace buffer, after which the event's
1812  * individual field values can be set through either
1813  * synth_event_add_next_val() or synth_event_add_val().
1814  *
1815  * A pointer to a trace_state object is passed in, which will keep
1816  * track of the current event trace state until the event trace is
1817  * closed (and the event finally traced) using
1818  * synth_event_trace_end().
1819  *
1820  * Note that synth_event_trace_end() must be called after all values
1821  * have been added for each event trace, regardless of whether adding
1822  * all field values succeeded or not.
1823  *
1824  * Note also that for a given event trace, all fields must be added
1825  * using either synth_event_add_next_val() or synth_event_add_val()
1826  * but not both together or interleaved.
1827  *
1828  * Return: 0 on success, err otherwise.
1829  */
1830 int synth_event_trace_start(struct trace_event_file *file,
1831                             struct synth_event_trace_state *trace_state)
1832 {
1833         int ret;
1834
1835         if (!trace_state)
1836                 return -EINVAL;
1837
1838         ret = __synth_event_trace_init(file, trace_state);
1839         if (ret) {
1840                 if (ret == -ENOENT)
1841                         ret = 0; /* just disabled, not really an error */
1842                 return ret;
1843         }
1844
1845         if (trace_state->event->n_dynamic_fields)
1846                 return -ENOTSUPP;
1847
1848         ret = __synth_event_trace_start(file, trace_state, 0);
1849
1850         return ret;
1851 }
1852 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1853
1854 static int __synth_event_add_val(const char *field_name, u64 val,
1855                                  struct synth_event_trace_state *trace_state)
1856 {
1857         struct synth_field *field = NULL;
1858         struct synth_trace_event *entry;
1859         struct synth_event *event;
1860         int i, ret = 0;
1861
1862         if (!trace_state) {
1863                 ret = -EINVAL;
1864                 goto out;
1865         }
1866
1867         /* can't mix add_next_synth_val() with add_synth_val() */
1868         if (field_name) {
1869                 if (trace_state->add_next) {
1870                         ret = -EINVAL;
1871                         goto out;
1872                 }
1873                 trace_state->add_name = true;
1874         } else {
1875                 if (trace_state->add_name) {
1876                         ret = -EINVAL;
1877                         goto out;
1878                 }
1879                 trace_state->add_next = true;
1880         }
1881
1882         if (trace_state->disabled)
1883                 goto out;
1884
1885         event = trace_state->event;
1886         if (trace_state->add_name) {
1887                 for (i = 0; i < event->n_fields; i++) {
1888                         field = event->fields[i];
1889                         if (strcmp(field->name, field_name) == 0)
1890                                 break;
1891                 }
1892                 if (!field) {
1893                         ret = -EINVAL;
1894                         goto out;
1895                 }
1896         } else {
1897                 if (trace_state->cur_field >= event->n_fields) {
1898                         ret = -EINVAL;
1899                         goto out;
1900                 }
1901                 field = event->fields[trace_state->cur_field++];
1902         }
1903
1904         entry = trace_state->entry;
1905         if (field->is_string) {
1906                 char *str_val = (char *)(long)val;
1907                 char *str_field;
1908
1909                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
1910                         ret = -EINVAL;
1911                         goto out;
1912                 }
1913
1914                 if (!str_val) {
1915                         ret = -EINVAL;
1916                         goto out;
1917                 }
1918
1919                 str_field = (char *)&entry->fields[field->offset];
1920                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
1921         } else {
1922                 switch (field->size) {
1923                 case 1:
1924                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
1925                         break;
1926
1927                 case 2:
1928                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
1929                         break;
1930
1931                 case 4:
1932                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
1933                         break;
1934
1935                 default:
1936                         trace_state->entry->fields[field->offset] = val;
1937                         break;
1938                 }
1939         }
1940  out:
1941         return ret;
1942 }
1943
1944 /**
1945  * synth_event_add_next_val - Add the next field's value to an open synth trace
1946  * @val: The value to set the next field to
1947  * @trace_state: A pointer to object tracking the piecewise trace state
1948  *
1949  * Set the value of the next field in an event that's been opened by
1950  * synth_event_trace_start().
1951  *
1952  * The val param should be the value cast to u64.  If the value points
1953  * to a string, the val param should be a char * cast to u64.
1954  *
1955  * This function assumes all the fields in an event are to be set one
1956  * after another - successive calls to this function are made, one for
1957  * each field, in the order of the fields in the event, until all
1958  * fields have been set.  If you'd rather set each field individually
1959  * without regard to ordering, synth_event_add_val() can be used
1960  * instead.
1961  *
1962  * Note however that synth_event_add_next_val() and
1963  * synth_event_add_val() can't be intermixed for a given event trace -
1964  * one or the other but not both can be used at the same time.
1965  *
1966  * Note also that synth_event_trace_end() must be called after all
1967  * values have been added for each event trace, regardless of whether
1968  * adding all field values succeeded or not.
1969  *
1970  * Return: 0 on success, err otherwise.
1971  */
1972 int synth_event_add_next_val(u64 val,
1973                              struct synth_event_trace_state *trace_state)
1974 {
1975         return __synth_event_add_val(NULL, val, trace_state);
1976 }
1977 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
1978
1979 /**
1980  * synth_event_add_val - Add a named field's value to an open synth trace
1981  * @field_name: The name of the synthetic event field value to set
1982  * @val: The value to set the named field to
1983  * @trace_state: A pointer to object tracking the piecewise trace state
1984  *
1985  * Set the value of the named field in an event that's been opened by
1986  * synth_event_trace_start().
1987  *
1988  * The val param should be the value cast to u64.  If the value points
1989  * to a string, the val param should be a char * cast to u64.
1990  *
1991  * This function looks up the field name, and if found, sets the field
1992  * to the specified value.  This lookup makes this function more
1993  * expensive than synth_event_add_next_val(), so use that or the
1994  * none-piecewise synth_event_trace() instead if efficiency is more
1995  * important.
1996  *
1997  * Note however that synth_event_add_next_val() and
1998  * synth_event_add_val() can't be intermixed for a given event trace -
1999  * one or the other but not both can be used at the same time.
2000  *
2001  * Note also that synth_event_trace_end() must be called after all
2002  * values have been added for each event trace, regardless of whether
2003  * adding all field values succeeded or not.
2004  *
2005  * Return: 0 on success, err otherwise.
2006  */
2007 int synth_event_add_val(const char *field_name, u64 val,
2008                         struct synth_event_trace_state *trace_state)
2009 {
2010         return __synth_event_add_val(field_name, val, trace_state);
2011 }
2012 EXPORT_SYMBOL_GPL(synth_event_add_val);
2013
2014 /**
2015  * synth_event_trace_end - End piecewise synthetic event trace
2016  * @trace_state: A pointer to object tracking the piecewise trace state
2017  *
2018  * End the trace of a synthetic event opened by
2019  * synth_event_trace__start().
2020  *
2021  * This function 'closes' an event trace, which basically means that
2022  * it commits the reserved event and cleans up other loose ends.
2023  *
2024  * A pointer to a trace_state object is passed in, which will keep
2025  * track of the current event trace state opened with
2026  * synth_event_trace_start().
2027  *
2028  * Note that this function must be called after all values have been
2029  * added for each event trace, regardless of whether adding all field
2030  * values succeeded or not.
2031  *
2032  * Return: 0 on success, err otherwise.
2033  */
2034 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2035 {
2036         if (!trace_state)
2037                 return -EINVAL;
2038
2039         __synth_event_trace_end(trace_state);
2040
2041         return 0;
2042 }
2043 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2044
2045 static int create_synth_event(const char *raw_command)
2046 {
2047         char *fields, *p;
2048         const char *name;
2049         int len, ret = 0;
2050
2051         raw_command = skip_spaces(raw_command);
2052         if (raw_command[0] == '\0')
2053                 return ret;
2054
2055         last_cmd_set(raw_command);
2056
2057         name = raw_command;
2058
2059         /* Don't try to process if not our system */
2060         if (name[0] != 's' || name[1] != ':')
2061                 return -ECANCELED;
2062         name += 2;
2063
2064         p = strpbrk(raw_command, " \t");
2065         if (!p) {
2066                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2067                 return -EINVAL;
2068         }
2069
2070         fields = skip_spaces(p);
2071
2072         /* This interface accepts group name prefix */
2073         if (strchr(name, '/')) {
2074                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2075                 if (len == 0) {
2076                         synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2077                         return -EINVAL;
2078                 }
2079                 name += len;
2080         }
2081
2082         len = name - raw_command;
2083
2084         ret = check_command(raw_command + len);
2085         if (ret) {
2086                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2087                 return ret;
2088         }
2089
2090         name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2091         if (!name)
2092                 return -ENOMEM;
2093
2094         ret = __create_synth_event(name, fields);
2095
2096         kfree(name);
2097
2098         return ret;
2099 }
2100
2101 static int synth_event_release(struct dyn_event *ev)
2102 {
2103         struct synth_event *event = to_synth_event(ev);
2104         int ret;
2105
2106         if (event->ref)
2107                 return -EBUSY;
2108
2109         if (trace_event_dyn_busy(&event->call))
2110                 return -EBUSY;
2111
2112         ret = unregister_synth_event(event);
2113         if (ret)
2114                 return ret;
2115
2116         dyn_event_remove(ev);
2117         free_synth_event(event);
2118         return 0;
2119 }
2120
2121 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2122 {
2123         struct synth_field *field;
2124         unsigned int i;
2125         char *type, *t;
2126
2127         seq_printf(m, "%s\t", event->name);
2128
2129         for (i = 0; i < event->n_fields; i++) {
2130                 field = event->fields[i];
2131
2132                 type = field->type;
2133                 t = strstr(type, "__data_loc");
2134                 if (t) { /* __data_loc belongs in format but not event desc */
2135                         t += sizeof("__data_loc");
2136                         type = t;
2137                 }
2138
2139                 /* parameter values */
2140                 seq_printf(m, "%s %s%s", type, field->name,
2141                            i == event->n_fields - 1 ? "" : "; ");
2142         }
2143
2144         seq_putc(m, '\n');
2145
2146         return 0;
2147 }
2148
2149 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2150 {
2151         struct synth_event *event = to_synth_event(ev);
2152
2153         seq_printf(m, "s:%s/", event->class.system);
2154
2155         return __synth_event_show(m, event);
2156 }
2157
2158 static int synth_events_seq_show(struct seq_file *m, void *v)
2159 {
2160         struct dyn_event *ev = v;
2161
2162         if (!is_synth_event(ev))
2163                 return 0;
2164
2165         return __synth_event_show(m, to_synth_event(ev));
2166 }
2167
2168 static const struct seq_operations synth_events_seq_op = {
2169         .start  = dyn_event_seq_start,
2170         .next   = dyn_event_seq_next,
2171         .stop   = dyn_event_seq_stop,
2172         .show   = synth_events_seq_show,
2173 };
2174
2175 static int synth_events_open(struct inode *inode, struct file *file)
2176 {
2177         int ret;
2178
2179         ret = security_locked_down(LOCKDOWN_TRACEFS);
2180         if (ret)
2181                 return ret;
2182
2183         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2184                 ret = dyn_events_release_all(&synth_event_ops);
2185                 if (ret < 0)
2186                         return ret;
2187         }
2188
2189         return seq_open(file, &synth_events_seq_op);
2190 }
2191
2192 static ssize_t synth_events_write(struct file *file,
2193                                   const char __user *buffer,
2194                                   size_t count, loff_t *ppos)
2195 {
2196         return trace_parse_run_command(file, buffer, count, ppos,
2197                                        create_or_delete_synth_event);
2198 }
2199
2200 static const struct file_operations synth_events_fops = {
2201         .open           = synth_events_open,
2202         .write          = synth_events_write,
2203         .read           = seq_read,
2204         .llseek         = seq_lseek,
2205         .release        = seq_release,
2206 };
2207
2208 /*
2209  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2210  * events in postcore_initcall without tracefs.
2211  */
2212 static __init int trace_events_synth_init_early(void)
2213 {
2214         int err = 0;
2215
2216         err = dyn_event_register(&synth_event_ops);
2217         if (err)
2218                 pr_warn("Could not register synth_event_ops\n");
2219
2220         return err;
2221 }
2222 core_initcall(trace_events_synth_init_early);
2223
2224 static __init int trace_events_synth_init(void)
2225 {
2226         struct dentry *entry = NULL;
2227         int err = 0;
2228         err = tracing_init_dentry();
2229         if (err)
2230                 goto err;
2231
2232         entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
2233                                     NULL, NULL, &synth_events_fops);
2234         if (!entry) {
2235                 err = -ENODEV;
2236                 goto err;
2237         }
2238
2239         return err;
2240  err:
2241         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2242
2243         return err;
2244 }
2245
2246 fs_initcall(trace_events_synth_init);