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