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 #include "trace_probe.h"
  21 #include "trace_probe_kernel.h"
  22
  23 #include "trace_synth.h"
  24
  25 #undef ERRORS
  26 #define ERRORS  \
  27         C(BAD_NAME,             "Illegal name"),                \
  28         C(INVALID_CMD,          "Command must be of the form: <name> field[;field] ..."),\
  29         C(INVALID_DYN_CMD,      "Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
  30         C(EVENT_EXISTS,         "Event already exists"),        \
  31         C(TOO_MANY_FIELDS,      "Too many fields"),             \
  32         C(INCOMPLETE_TYPE,      "Incomplete type"),             \
  33         C(INVALID_TYPE,         "Invalid type"),                \
  34         C(INVALID_FIELD,        "Invalid field"),               \
  35         C(INVALID_ARRAY_SPEC,   "Invalid array specification"),
  36
  37 #undef C
  38 #define C(a, b)         SYNTH_ERR_##a
  39
  40 enum { ERRORS };
  41
  42 #undef C
  43 #define C(a, b)         b
  44
  45 static const char *err_text[] = { ERRORS };
  46
  47 static DEFINE_MUTEX(lastcmd_mutex);
  48 static char *last_cmd;
  49
  50 static int errpos(const char *str)
  51 {
  52         int ret = 0;
  53
  54         mutex_lock(&lastcmd_mutex);
  55         if (!str || !last_cmd)
  56                 goto out;
  57
  58         ret = err_pos(last_cmd, str);
  59  out:
  60         mutex_unlock(&lastcmd_mutex);
  61         return ret;
  62 }
  63
  64 static void last_cmd_set(const char *str)
  65 {
  66         if (!str)
  67                 return;
  68
  69         mutex_lock(&lastcmd_mutex);
  70         kfree(last_cmd);
  71         last_cmd = kstrdup(str, GFP_KERNEL);
  72         mutex_unlock(&lastcmd_mutex);
  73 }
  74
  75 static void synth_err(u8 err_type, u16 err_pos)
  76 {
  77         mutex_lock(&lastcmd_mutex);
  78         if (!last_cmd)
  79                 goto out;
  80
  81         tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
  82                         err_type, err_pos);
  83  out:
  84         mutex_unlock(&lastcmd_mutex);
  85 }
  86
  87 static int create_synth_event(const char *raw_command);
  88 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
  89 static int synth_event_release(struct dyn_event *ev);
  90 static bool synth_event_is_busy(struct dyn_event *ev);
  91 static bool synth_event_match(const char *system, const char *event,
  92                         int argc, const char **argv, struct dyn_event *ev);
  93
  94 static struct dyn_event_operations synth_event_ops = {
  95         .create = create_synth_event,
  96         .show = synth_event_show,
  97         .is_busy = synth_event_is_busy,
  98         .free = synth_event_release,
  99         .match = synth_event_match,
 100 };
 101
 102 static bool is_synth_event(struct dyn_event *ev)
 103 {
 104         return ev->ops == &synth_event_ops;
 105 }
 106
 107 static struct synth_event *to_synth_event(struct dyn_event *ev)
 108 {
 109         return container_of(ev, struct synth_event, devent);
 110 }
 111
 112 static bool synth_event_is_busy(struct dyn_event *ev)
 113 {
 114         struct synth_event *event = to_synth_event(ev);
 115
 116         return event->ref != 0;
 117 }
 118
 119 static bool synth_event_match(const char *system, const char *event,
 120                         int argc, const char **argv, struct dyn_event *ev)
 121 {
 122         struct synth_event *sev = to_synth_event(ev);
 123
 124         return strcmp(sev->name, event) == 0 &&
 125                 (!system || strcmp(system, SYNTH_SYSTEM) == 0);
 126 }
 127
 128 struct synth_trace_event {
 129         struct trace_entry      ent;
 130         u64                     fields[];
 131 };
 132
 133 static int synth_event_define_fields(struct trace_event_call *call)
 134 {
 135         struct synth_trace_event trace;
 136         int offset = offsetof(typeof(trace), fields);
 137         struct synth_event *event = call->data;
 138         unsigned int i, size, n_u64;
 139         char *name, *type;
 140         bool is_signed;
 141         int ret = 0;
 142
 143         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 144                 size = event->fields[i]->size;
 145                 is_signed = event->fields[i]->is_signed;
 146                 type = event->fields[i]->type;
 147                 name = event->fields[i]->name;
 148                 ret = trace_define_field(call, type, name, offset, size,
 149                                          is_signed, FILTER_OTHER);
 150                 if (ret)
 151                         break;
 152
 153                 event->fields[i]->offset = n_u64;
 154
 155                 if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
 156                         offset += STR_VAR_LEN_MAX;
 157                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 158                 } else {
 159                         offset += sizeof(u64);
 160                         n_u64++;
 161                 }
 162         }
 163
 164         event->n_u64 = n_u64;
 165
 166         return ret;
 167 }
 168
 169 static bool synth_field_signed(char *type)
 170 {
 171         if (str_has_prefix(type, "u"))
 172                 return false;
 173         if (strcmp(type, "gfp_t") == 0)
 174                 return false;
 175
 176         return true;
 177 }
 178
 179 static int synth_field_is_string(char *type)
 180 {
 181         if (strstr(type, "char[") != NULL)
 182                 return true;
 183
 184         return false;
 185 }
 186
 187 static int synth_field_is_stack(char *type)
 188 {
 189         if (strstr(type, "long[") != NULL)
 190                 return true;
 191
 192         return false;
 193 }
 194
 195 static int synth_field_string_size(char *type)
 196 {
 197         char buf[4], *end, *start;
 198         unsigned int len;
 199         int size, err;
 200
 201         start = strstr(type, "char[");
 202         if (start == NULL)
 203                 return -EINVAL;
 204         start += sizeof("char[") - 1;
 205
 206         end = strchr(type, ']');
 207         if (!end || end < start || type + strlen(type) > end + 1)
 208                 return -EINVAL;
 209
 210         len = end - start;
 211         if (len > 3)
 212                 return -EINVAL;
 213
 214         if (len == 0)
 215                 return 0; /* variable-length string */
 216
 217         strncpy(buf, start, len);
 218         buf[len] = '\0';
 219
 220         err = kstrtouint(buf, 0, &size);
 221         if (err)
 222                 return err;
 223
 224         if (size > STR_VAR_LEN_MAX)
 225                 return -EINVAL;
 226
 227         return size;
 228 }
 229
 230 static int synth_field_size(char *type)
 231 {
 232         int size = 0;
 233
 234         if (strcmp(type, "s64") == 0)
 235                 size = sizeof(s64);
 236         else if (strcmp(type, "u64") == 0)
 237                 size = sizeof(u64);
 238         else if (strcmp(type, "s32") == 0)
 239                 size = sizeof(s32);
 240         else if (strcmp(type, "u32") == 0)
 241                 size = sizeof(u32);
 242         else if (strcmp(type, "s16") == 0)
 243                 size = sizeof(s16);
 244         else if (strcmp(type, "u16") == 0)
 245                 size = sizeof(u16);
 246         else if (strcmp(type, "s8") == 0)
 247                 size = sizeof(s8);
 248         else if (strcmp(type, "u8") == 0)
 249                 size = sizeof(u8);
 250         else if (strcmp(type, "char") == 0)
 251                 size = sizeof(char);
 252         else if (strcmp(type, "unsigned char") == 0)
 253                 size = sizeof(unsigned char);
 254         else if (strcmp(type, "int") == 0)
 255                 size = sizeof(int);
 256         else if (strcmp(type, "unsigned int") == 0)
 257                 size = sizeof(unsigned int);
 258         else if (strcmp(type, "long") == 0)
 259                 size = sizeof(long);
 260         else if (strcmp(type, "unsigned long") == 0)
 261                 size = sizeof(unsigned long);
 262         else if (strcmp(type, "bool") == 0)
 263                 size = sizeof(bool);
 264         else if (strcmp(type, "pid_t") == 0)
 265                 size = sizeof(pid_t);
 266         else if (strcmp(type, "gfp_t") == 0)
 267                 size = sizeof(gfp_t);
 268         else if (synth_field_is_string(type))
 269                 size = synth_field_string_size(type);
 270         else if (synth_field_is_stack(type))
 271                 size = 0;
 272
 273         return size;
 274 }
 275
 276 static const char *synth_field_fmt(char *type)
 277 {
 278         const char *fmt = "%llu";
 279
 280         if (strcmp(type, "s64") == 0)
 281                 fmt = "%lld";
 282         else if (strcmp(type, "u64") == 0)
 283                 fmt = "%llu";
 284         else if (strcmp(type, "s32") == 0)
 285                 fmt = "%d";
 286         else if (strcmp(type, "u32") == 0)
 287                 fmt = "%u";
 288         else if (strcmp(type, "s16") == 0)
 289                 fmt = "%d";
 290         else if (strcmp(type, "u16") == 0)
 291                 fmt = "%u";
 292         else if (strcmp(type, "s8") == 0)
 293                 fmt = "%d";
 294         else if (strcmp(type, "u8") == 0)
 295                 fmt = "%u";
 296         else if (strcmp(type, "char") == 0)
 297                 fmt = "%d";
 298         else if (strcmp(type, "unsigned char") == 0)
 299                 fmt = "%u";
 300         else if (strcmp(type, "int") == 0)
 301                 fmt = "%d";
 302         else if (strcmp(type, "unsigned int") == 0)
 303                 fmt = "%u";
 304         else if (strcmp(type, "long") == 0)
 305                 fmt = "%ld";
 306         else if (strcmp(type, "unsigned long") == 0)
 307                 fmt = "%lu";
 308         else if (strcmp(type, "bool") == 0)
 309                 fmt = "%d";
 310         else if (strcmp(type, "pid_t") == 0)
 311                 fmt = "%d";
 312         else if (strcmp(type, "gfp_t") == 0)
 313                 fmt = "%x";
 314         else if (synth_field_is_string(type))
 315                 fmt = "%.*s";
 316         else if (synth_field_is_stack(type))
 317                 fmt = "%s";
 318
 319         return fmt;
 320 }
 321
 322 static void print_synth_event_num_val(struct trace_seq *s,
 323                                       char *print_fmt, char *name,
 324                                       int size, u64 val, char *space)
 325 {
 326         switch (size) {
 327         case 1:
 328                 trace_seq_printf(s, print_fmt, name, (u8)val, space);
 329                 break;
 330
 331         case 2:
 332                 trace_seq_printf(s, print_fmt, name, (u16)val, space);
 333                 break;
 334
 335         case 4:
 336                 trace_seq_printf(s, print_fmt, name, (u32)val, space);
 337                 break;
 338
 339         default:
 340                 trace_seq_printf(s, print_fmt, name, val, space);
 341                 break;
 342         }
 343 }
 344
 345 static enum print_line_t print_synth_event(struct trace_iterator *iter,
 346                                            int flags,
 347                                            struct trace_event *event)
 348 {
 349         struct trace_array *tr = iter->tr;
 350         struct trace_seq *s = &iter->seq;
 351         struct synth_trace_event *entry;
 352         struct synth_event *se;
 353         unsigned int i, n_u64;
 354         char print_fmt[32];
 355         const char *fmt;
 356
 357         entry = (struct synth_trace_event *)iter->ent;
 358         se = container_of(event, struct synth_event, call.event);
 359
 360         trace_seq_printf(s, "%s: ", se->name);
 361
 362         for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
 363                 if (trace_seq_has_overflowed(s))
 364                         goto end;
 365
 366                 fmt = synth_field_fmt(se->fields[i]->type);
 367
 368                 /* parameter types */
 369                 if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
 370                         trace_seq_printf(s, "%s ", fmt);
 371
 372                 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
 373
 374                 /* parameter values */
 375                 if (se->fields[i]->is_string) {
 376                         if (se->fields[i]->is_dynamic) {
 377                                 u32 offset, data_offset;
 378                                 char *str_field;
 379
 380                                 offset = (u32)entry->fields[n_u64];
 381                                 data_offset = offset & 0xffff;
 382
 383                                 str_field = (char *)entry + data_offset;
 384
 385                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 386                                                  STR_VAR_LEN_MAX,
 387                                                  str_field,
 388                                                  i == se->n_fields - 1 ? "" : " ");
 389                                 n_u64++;
 390                         } else {
 391                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 392                                                  STR_VAR_LEN_MAX,
 393                                                  (char *)&entry->fields[n_u64],
 394                                                  i == se->n_fields - 1 ? "" : " ");
 395                                 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 396                         }
 397                 } else if (se->fields[i]->is_stack) {
 398                         u32 offset, data_offset, len;
 399                         unsigned long *p, *end;
 400
 401                         offset = (u32)entry->fields[n_u64];
 402                         data_offset = offset & 0xffff;
 403                         len = offset >> 16;
 404
 405                         p = (void *)entry + data_offset;
 406                         end = (void *)p + len - (sizeof(long) - 1);
 407
 408                         trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
 409
 410                         for (; *p && p < end; p++)
 411                                 trace_seq_printf(s, "=> %pS\n", (void *)*p);
 412                         n_u64++;
 413
 414                 } else {
 415                         struct trace_print_flags __flags[] = {
 416                             __def_gfpflag_names, {-1, NULL} };
 417                         char *space = (i == se->n_fields - 1 ? "" : " ");
 418
 419                         print_synth_event_num_val(s, print_fmt,
 420                                                   se->fields[i]->name,
 421                                                   se->fields[i]->size,
 422                                                   entry->fields[n_u64],
 423                                                   space);
 424
 425                         if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
 426                                 trace_seq_puts(s, " (");
 427                                 trace_print_flags_seq(s, "|",
 428                                                       entry->fields[n_u64],
 429                                                       __flags);
 430                                 trace_seq_putc(s, ')');
 431                         }
 432                         n_u64++;
 433                 }
 434         }
 435 end:
 436         trace_seq_putc(s, '\n');
 437
 438         return trace_handle_return(s);
 439 }
 440
 441 static struct trace_event_functions synth_event_funcs = {
 442         .trace          = print_synth_event
 443 };
 444
 445 static unsigned int trace_string(struct synth_trace_event *entry,
 446                                  struct synth_event *event,
 447                                  char *str_val,
 448                                  bool is_dynamic,
 449                                  unsigned int data_size,
 450                                  unsigned int *n_u64)
 451 {
 452         unsigned int len = 0;
 453         char *str_field;
 454         int ret;
 455
 456         if (is_dynamic) {
 457                 u32 data_offset;
 458
 459                 data_offset = struct_size(entry, fields, event->n_u64);
 460                 data_offset += data_size;
 461
 462                 len = fetch_store_strlen((unsigned long)str_val);
 463
 464                 data_offset |= len << 16;
 465                 *(u32 *)&entry->fields[*n_u64] = data_offset;
 466
 467                 ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
 468
 469                 (*n_u64)++;
 470         } else {
 471                 str_field = (char *)&entry->fields[*n_u64];
 472
 473 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 474                 if ((unsigned long)str_val < TASK_SIZE)
 475                         ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
 476                 else
 477 #endif
 478                         ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
 479
 480                 if (ret < 0)
 481                         strcpy(str_field, FAULT_STRING);
 482
 483                 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
 484         }
 485
 486         return len;
 487 }
 488
 489 static unsigned int trace_stack(struct synth_trace_event *entry,
 490                                  struct synth_event *event,
 491                                  long *stack,
 492                                  unsigned int data_size,
 493                                  unsigned int *n_u64)
 494 {
 495         unsigned int len;
 496         u32 data_offset;
 497         void *data_loc;
 498
 499         data_offset = struct_size(entry, fields, event->n_u64);
 500         data_offset += data_size;
 501
 502         for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
 503                 if (!stack[len])
 504                         break;
 505         }
 506
 507         /* Include the zero'd element if it fits */
 508         if (len < HIST_STACKTRACE_DEPTH)
 509                 len++;
 510
 511         len *= sizeof(long);
 512
 513         /* Find the dynamic section to copy the stack into. */
 514         data_loc = (void *)entry + data_offset;
 515         memcpy(data_loc, stack, len);
 516
 517         /* Fill in the field that holds the offset/len combo */
 518         data_offset |= len << 16;
 519         *(u32 *)&entry->fields[*n_u64] = data_offset;
 520
 521         (*n_u64)++;
 522
 523         return len;
 524 }
 525
 526 static notrace void trace_event_raw_event_synth(void *__data,
 527                                                 u64 *var_ref_vals,
 528                                                 unsigned int *var_ref_idx)
 529 {
 530         unsigned int i, n_u64, val_idx, len, data_size = 0;
 531         struct trace_event_file *trace_file = __data;
 532         struct synth_trace_event *entry;
 533         struct trace_event_buffer fbuffer;
 534         struct trace_buffer *buffer;
 535         struct synth_event *event;
 536         int fields_size = 0;
 537
 538         event = trace_file->event_call->data;
 539
 540         if (trace_trigger_soft_disabled(trace_file))
 541                 return;
 542
 543         fields_size = event->n_u64 * sizeof(u64);
 544
 545         for (i = 0; i < event->n_dynamic_fields; i++) {
 546                 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
 547                 char *str_val;
 548
 549                 val_idx = var_ref_idx[field_pos];
 550                 str_val = (char *)(long)var_ref_vals[val_idx];
 551
 552                 if (event->dynamic_fields[i]->is_stack) {
 553                         len = *((unsigned long *)str_val);
 554                         len *= sizeof(unsigned long);
 555                 } else {
 556                         len = fetch_store_strlen((unsigned long)str_val);
 557                 }
 558
 559                 fields_size += len;
 560         }
 561
 562         /*
 563          * Avoid ring buffer recursion detection, as this event
 564          * is being performed within another event.
 565          */
 566         buffer = trace_file->tr->array_buffer.buffer;
 567         ring_buffer_nest_start(buffer);
 568
 569         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 570                                            sizeof(*entry) + fields_size);
 571         if (!entry)
 572                 goto out;
 573
 574         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 575                 val_idx = var_ref_idx[i];
 576                 if (event->fields[i]->is_string) {
 577                         char *str_val = (char *)(long)var_ref_vals[val_idx];
 578
 579                         len = trace_string(entry, event, str_val,
 580                                            event->fields[i]->is_dynamic,
 581                                            data_size, &n_u64);
 582                         data_size += len; /* only dynamic string increments */
 583                 } else if (event->fields[i]->is_stack) {
 584                         long *stack = (long *)(long)var_ref_vals[val_idx];
 585
 586                         len = trace_stack(entry, event, stack,
 587                                            data_size, &n_u64);
 588                         data_size += len;
 589                 } else {
 590                         struct synth_field *field = event->fields[i];
 591                         u64 val = var_ref_vals[val_idx];
 592
 593                         switch (field->size) {
 594                         case 1:
 595                                 *(u8 *)&entry->fields[n_u64] = (u8)val;
 596                                 break;
 597
 598                         case 2:
 599                                 *(u16 *)&entry->fields[n_u64] = (u16)val;
 600                                 break;
 601
 602                         case 4:
 603                                 *(u32 *)&entry->fields[n_u64] = (u32)val;
 604                                 break;
 605
 606                         default:
 607                                 entry->fields[n_u64] = val;
 608                                 break;
 609                         }
 610                         n_u64++;
 611                 }
 612         }
 613
 614         trace_event_buffer_commit(&fbuffer);
 615 out:
 616         ring_buffer_nest_end(buffer);
 617 }
 618
 619 static void free_synth_event_print_fmt(struct trace_event_call *call)
 620 {
 621         if (call) {
 622                 kfree(call->print_fmt);
 623                 call->print_fmt = NULL;
 624         }
 625 }
 626
 627 static int __set_synth_event_print_fmt(struct synth_event *event,
 628                                        char *buf, int len)
 629 {
 630         const char *fmt;
 631         int pos = 0;
 632         int i;
 633
 634         /* When len=0, we just calculate the needed length */
 635 #define LEN_OR_ZERO (len ? len - pos : 0)
 636
 637         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 638         for (i = 0; i < event->n_fields; i++) {
 639                 fmt = synth_field_fmt(event->fields[i]->type);
 640                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 641                                 event->fields[i]->name, fmt,
 642                                 i == event->n_fields - 1 ? "" : ", ");
 643         }
 644         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 645
 646         for (i = 0; i < event->n_fields; i++) {
 647                 if (event->fields[i]->is_string &&
 648                     event->fields[i]->is_dynamic)
 649                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 650                                 ", __get_str(%s)", event->fields[i]->name);
 651                 else if (event->fields[i]->is_stack)
 652                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 653                                 ", __get_stacktrace(%s)", event->fields[i]->name);
 654                 else
 655                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 656                                         ", REC->%s", event->fields[i]->name);
 657         }
 658
 659 #undef LEN_OR_ZERO
 660
 661         /* return the length of print_fmt */
 662         return pos;
 663 }
 664
 665 static int set_synth_event_print_fmt(struct trace_event_call *call)
 666 {
 667         struct synth_event *event = call->data;
 668         char *print_fmt;
 669         int len;
 670
 671         /* First: called with 0 length to calculate the needed length */
 672         len = __set_synth_event_print_fmt(event, NULL, 0);
 673
 674         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 675         if (!print_fmt)
 676                 return -ENOMEM;
 677
 678         /* Second: actually write the @print_fmt */
 679         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 680         call->print_fmt = print_fmt;
 681
 682         return 0;
 683 }
 684
 685 static void free_synth_field(struct synth_field *field)
 686 {
 687         kfree(field->type);
 688         kfree(field->name);
 689         kfree(field);
 690 }
 691
 692 static int check_field_version(const char *prefix, const char *field_type,
 693                                const char *field_name)
 694 {
 695         /*
 696          * For backward compatibility, the old synthetic event command
 697          * format did not require semicolons, and in order to not
 698          * break user space, that old format must still work. If a new
 699          * feature is added, then the format that uses the new feature
 700          * will be required to have semicolons, as nothing that uses
 701          * the old format would be using the new, yet to be created,
 702          * feature. When a new feature is added, this will detect it,
 703          * and return a number greater than 1, and require the format
 704          * to use semicolons.
 705          */
 706         return 1;
 707 }
 708
 709 static struct synth_field *parse_synth_field(int argc, char **argv,
 710                                              int *consumed, int *field_version)
 711 {
 712         const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 713         struct synth_field *field;
 714         int len, ret = -ENOMEM;
 715         struct seq_buf s;
 716         ssize_t size;
 717
 718         if (!strcmp(field_type, "unsigned")) {
 719                 if (argc < 3) {
 720                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 721                         return ERR_PTR(-EINVAL);
 722                 }
 723                 prefix = "unsigned ";
 724                 field_type = argv[1];
 725                 field_name = argv[2];
 726                 *consumed += 3;
 727         } else {
 728                 field_name = argv[1];
 729                 *consumed += 2;
 730         }
 731
 732         if (!field_name) {
 733                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
 734                 return ERR_PTR(-EINVAL);
 735         }
 736
 737         *field_version = check_field_version(prefix, field_type, field_name);
 738
 739         field = kzalloc(sizeof(*field), GFP_KERNEL);
 740         if (!field)
 741                 return ERR_PTR(-ENOMEM);
 742
 743         len = strlen(field_name);
 744         array = strchr(field_name, '[');
 745         if (array)
 746                 len -= strlen(array);
 747
 748         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 749         if (!field->name)
 750                 goto free;
 751
 752         if (!is_good_name(field->name)) {
 753                 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 754                 ret = -EINVAL;
 755                 goto free;
 756         }
 757
 758         len = strlen(field_type) + 1;
 759
 760         if (array)
 761                 len += strlen(array);
 762
 763         if (prefix)
 764                 len += strlen(prefix);
 765
 766         field->type = kzalloc(len, GFP_KERNEL);
 767         if (!field->type)
 768                 goto free;
 769
 770         seq_buf_init(&s, field->type, len);
 771         if (prefix)
 772                 seq_buf_puts(&s, prefix);
 773         seq_buf_puts(&s, field_type);
 774         if (array)
 775                 seq_buf_puts(&s, array);
 776         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 777                 goto free;
 778
 779         s.buffer[s.len] = '\0';
 780
 781         size = synth_field_size(field->type);
 782         if (size < 0) {
 783                 if (array)
 784                         synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
 785                 else
 786                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 787                 ret = -EINVAL;
 788                 goto free;
 789         } else if (size == 0) {
 790                 if (synth_field_is_string(field->type) ||
 791                     synth_field_is_stack(field->type)) {
 792                         char *type;
 793
 794                         len = sizeof("__data_loc ") + strlen(field->type) + 1;
 795                         type = kzalloc(len, GFP_KERNEL);
 796                         if (!type)
 797                                 goto free;
 798
 799                         seq_buf_init(&s, type, len);
 800                         seq_buf_puts(&s, "__data_loc ");
 801                         seq_buf_puts(&s, field->type);
 802
 803                         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 804                                 goto free;
 805                         s.buffer[s.len] = '\0';
 806
 807                         kfree(field->type);
 808                         field->type = type;
 809
 810                         field->is_dynamic = true;
 811                         size = sizeof(u64);
 812                 } else {
 813                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 814                         ret = -EINVAL;
 815                         goto free;
 816                 }
 817         }
 818         field->size = size;
 819
 820         if (synth_field_is_string(field->type))
 821                 field->is_string = true;
 822         else if (synth_field_is_stack(field->type))
 823                 field->is_stack = true;
 824
 825         field->is_signed = synth_field_signed(field->type);
 826  out:
 827         return field;
 828  free:
 829         free_synth_field(field);
 830         field = ERR_PTR(ret);
 831         goto out;
 832 }
 833
 834 static void free_synth_tracepoint(struct tracepoint *tp)
 835 {
 836         if (!tp)
 837                 return;
 838
 839         kfree(tp->name);
 840         kfree(tp);
 841 }
 842
 843 static struct tracepoint *alloc_synth_tracepoint(char *name)
 844 {
 845         struct tracepoint *tp;
 846
 847         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 848         if (!tp)
 849                 return ERR_PTR(-ENOMEM);
 850
 851         tp->name = kstrdup(name, GFP_KERNEL);
 852         if (!tp->name) {
 853                 kfree(tp);
 854                 return ERR_PTR(-ENOMEM);
 855         }
 856
 857         return tp;
 858 }
 859
 860 struct synth_event *find_synth_event(const char *name)
 861 {
 862         struct dyn_event *pos;
 863         struct synth_event *event;
 864
 865         for_each_dyn_event(pos) {
 866                 if (!is_synth_event(pos))
 867                         continue;
 868                 event = to_synth_event(pos);
 869                 if (strcmp(event->name, name) == 0)
 870                         return event;
 871         }
 872
 873         return NULL;
 874 }
 875
 876 static struct trace_event_fields synth_event_fields_array[] = {
 877         { .type = TRACE_FUNCTION_TYPE,
 878           .define_fields = synth_event_define_fields },
 879         {}
 880 };
 881
 882 static int register_synth_event(struct synth_event *event)
 883 {
 884         struct trace_event_call *call = &event->call;
 885         int ret = 0;
 886
 887         event->call.class = &event->class;
 888         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 889         if (!event->class.system) {
 890                 ret = -ENOMEM;
 891                 goto out;
 892         }
 893
 894         event->tp = alloc_synth_tracepoint(event->name);
 895         if (IS_ERR(event->tp)) {
 896                 ret = PTR_ERR(event->tp);
 897                 event->tp = NULL;
 898                 goto out;
 899         }
 900
 901         INIT_LIST_HEAD(&call->class->fields);
 902         call->event.funcs = &synth_event_funcs;
 903         call->class->fields_array = synth_event_fields_array;
 904
 905         ret = register_trace_event(&call->event);
 906         if (!ret) {
 907                 ret = -ENODEV;
 908                 goto out;
 909         }
 910         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 911         call->class->reg = trace_event_reg;
 912         call->class->probe = trace_event_raw_event_synth;
 913         call->data = event;
 914         call->tp = event->tp;
 915
 916         ret = trace_add_event_call(call);
 917         if (ret) {
 918                 pr_warn("Failed to register synthetic event: %s\n",
 919                         trace_event_name(call));
 920                 goto err;
 921         }
 922
 923         ret = set_synth_event_print_fmt(call);
 924         /* unregister_trace_event() will be called inside */
 925         if (ret < 0)
 926                 trace_remove_event_call(call);
 927  out:
 928         return ret;
 929  err:
 930         unregister_trace_event(&call->event);
 931         goto out;
 932 }
 933
 934 static int unregister_synth_event(struct synth_event *event)
 935 {
 936         struct trace_event_call *call = &event->call;
 937         int ret;
 938
 939         ret = trace_remove_event_call(call);
 940
 941         return ret;
 942 }
 943
 944 static void free_synth_event(struct synth_event *event)
 945 {
 946         unsigned int i;
 947
 948         if (!event)
 949                 return;
 950
 951         for (i = 0; i < event->n_fields; i++)
 952                 free_synth_field(event->fields[i]);
 953
 954         kfree(event->fields);
 955         kfree(event->dynamic_fields);
 956         kfree(event->name);
 957         kfree(event->class.system);
 958         free_synth_tracepoint(event->tp);
 959         free_synth_event_print_fmt(&event->call);
 960         kfree(event);
 961 }
 962
 963 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 964                                              struct synth_field **fields)
 965 {
 966         unsigned int i, j, n_dynamic_fields = 0;
 967         struct synth_event *event;
 968
 969         event = kzalloc(sizeof(*event), GFP_KERNEL);
 970         if (!event) {
 971                 event = ERR_PTR(-ENOMEM);
 972                 goto out;
 973         }
 974
 975         event->name = kstrdup(name, GFP_KERNEL);
 976         if (!event->name) {
 977                 kfree(event);
 978                 event = ERR_PTR(-ENOMEM);
 979                 goto out;
 980         }
 981
 982         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 983         if (!event->fields) {
 984                 free_synth_event(event);
 985                 event = ERR_PTR(-ENOMEM);
 986                 goto out;
 987         }
 988
 989         for (i = 0; i < n_fields; i++)
 990                 if (fields[i]->is_dynamic)
 991                         n_dynamic_fields++;
 992
 993         if (n_dynamic_fields) {
 994                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 995                                                 sizeof(*event->dynamic_fields),
 996                                                 GFP_KERNEL);
 997                 if (!event->dynamic_fields) {
 998                         free_synth_event(event);
 999                         event = ERR_PTR(-ENOMEM);
1000                         goto out;
1001                 }
1002         }
1003
1004         dyn_event_init(&event->devent, &synth_event_ops);
1005
1006         for (i = 0, j = 0; i < n_fields; i++) {
1007                 fields[i]->field_pos = i;
1008                 event->fields[i] = fields[i];
1009
1010                 if (fields[i]->is_dynamic)
1011                         event->dynamic_fields[j++] = fields[i];
1012         }
1013         event->n_dynamic_fields = j;
1014         event->n_fields = n_fields;
1015  out:
1016         return event;
1017 }
1018
1019 static int synth_event_check_arg_fn(void *data)
1020 {
1021         struct dynevent_arg_pair *arg_pair = data;
1022         int size;
1023
1024         size = synth_field_size((char *)arg_pair->lhs);
1025         if (size == 0) {
1026                 if (strstr((char *)arg_pair->lhs, "["))
1027                         return 0;
1028         }
1029
1030         return size ? 0 : -EINVAL;
1031 }
1032
1033 /**
1034  * synth_event_add_field - Add a new field to a synthetic event cmd
1035  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1036  * @type: The type of the new field to add
1037  * @name: The name of the new field to add
1038  *
1039  * Add a new field to a synthetic event cmd object.  Field ordering is in
1040  * the same order the fields are added.
1041  *
1042  * See synth_field_size() for available types. If field_name contains
1043  * [n] the field is considered to be an array.
1044  *
1045  * Return: 0 if successful, error otherwise.
1046  */
1047 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
1048                           const char *name)
1049 {
1050         struct dynevent_arg_pair arg_pair;
1051         int ret;
1052
1053         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1054                 return -EINVAL;
1055
1056         if (!type || !name)
1057                 return -EINVAL;
1058
1059         dynevent_arg_pair_init(&arg_pair, 0, ';');
1060
1061         arg_pair.lhs = type;
1062         arg_pair.rhs = name;
1063
1064         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
1065         if (ret)
1066                 return ret;
1067
1068         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1069                 ret = -EINVAL;
1070
1071         return ret;
1072 }
1073 EXPORT_SYMBOL_GPL(synth_event_add_field);
1074
1075 /**
1076  * synth_event_add_field_str - Add a new field to a synthetic event cmd
1077  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1078  * @type_name: The type and name of the new field to add, as a single string
1079  *
1080  * Add a new field to a synthetic event cmd object, as a single
1081  * string.  The @type_name string is expected to be of the form 'type
1082  * name', which will be appended by ';'.  No sanity checking is done -
1083  * what's passed in is assumed to already be well-formed.  Field
1084  * ordering is in the same order the fields are added.
1085  *
1086  * See synth_field_size() for available types. If field_name contains
1087  * [n] the field is considered to be an array.
1088  *
1089  * Return: 0 if successful, error otherwise.
1090  */
1091 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
1092 {
1093         struct dynevent_arg arg;
1094         int ret;
1095
1096         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1097                 return -EINVAL;
1098
1099         if (!type_name)
1100                 return -EINVAL;
1101
1102         dynevent_arg_init(&arg, ';');
1103
1104         arg.str = type_name;
1105
1106         ret = dynevent_arg_add(cmd, &arg, NULL);
1107         if (ret)
1108                 return ret;
1109
1110         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1111                 ret = -EINVAL;
1112
1113         return ret;
1114 }
1115 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1116
1117 /**
1118  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1119  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1120  * @fields: An array of type/name field descriptions
1121  * @n_fields: The number of field descriptions contained in the fields array
1122  *
1123  * Add a new set of fields to a synthetic event cmd object.  The event
1124  * fields that will be defined for the event should be passed in as an
1125  * array of struct synth_field_desc, and the number of elements in the
1126  * array passed in as n_fields.  Field ordering will retain the
1127  * ordering given in the fields array.
1128  *
1129  * See synth_field_size() for available types. If field_name contains
1130  * [n] the field is considered to be an array.
1131  *
1132  * Return: 0 if successful, error otherwise.
1133  */
1134 int synth_event_add_fields(struct dynevent_cmd *cmd,
1135                            struct synth_field_desc *fields,
1136                            unsigned int n_fields)
1137 {
1138         unsigned int i;
1139         int ret = 0;
1140
1141         for (i = 0; i < n_fields; i++) {
1142                 if (fields[i].type == NULL || fields[i].name == NULL) {
1143                         ret = -EINVAL;
1144                         break;
1145                 }
1146
1147                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1148                 if (ret)
1149                         break;
1150         }
1151
1152         return ret;
1153 }
1154 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1155
1156 /**
1157  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1158  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1159  * @name: The name of the synthetic event
1160  * @mod: The module creating the event, NULL if not created from a module
1161  * @args: Variable number of arg (pairs), one pair for each field
1162  *
1163  * NOTE: Users normally won't want to call this function directly, but
1164  * rather use the synth_event_gen_cmd_start() wrapper, which
1165  * automatically adds a NULL to the end of the arg list.  If this
1166  * function is used directly, make sure the last arg in the variable
1167  * arg list is NULL.
1168  *
1169  * Generate a synthetic event command to be executed by
1170  * synth_event_gen_cmd_end().  This function can be used to generate
1171  * the complete command or only the first part of it; in the latter
1172  * case, synth_event_add_field(), synth_event_add_field_str(), or
1173  * synth_event_add_fields() can be used to add more fields following
1174  * this.
1175  *
1176  * There should be an even number variable args, each pair consisting
1177  * of a type followed by a field name.
1178  *
1179  * See synth_field_size() for available types. If field_name contains
1180  * [n] the field is considered to be an array.
1181  *
1182  * Return: 0 if successful, error otherwise.
1183  */
1184 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1185                                 struct module *mod, ...)
1186 {
1187         struct dynevent_arg arg;
1188         va_list args;
1189         int ret;
1190
1191         cmd->event_name = name;
1192         cmd->private_data = mod;
1193
1194         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1195                 return -EINVAL;
1196
1197         dynevent_arg_init(&arg, 0);
1198         arg.str = name;
1199         ret = dynevent_arg_add(cmd, &arg, NULL);
1200         if (ret)
1201                 return ret;
1202
1203         va_start(args, mod);
1204         for (;;) {
1205                 const char *type, *name;
1206
1207                 type = va_arg(args, const char *);
1208                 if (!type)
1209                         break;
1210                 name = va_arg(args, const char *);
1211                 if (!name)
1212                         break;
1213
1214                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1215                         ret = -EINVAL;
1216                         break;
1217                 }
1218
1219                 ret = synth_event_add_field(cmd, type, name);
1220                 if (ret)
1221                         break;
1222         }
1223         va_end(args);
1224
1225         return ret;
1226 }
1227 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1228
1229 /**
1230  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1231  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1232  * @name: The name of the synthetic event
1233  * @mod: The module creating the event, NULL if not created from a module
1234  * @fields: An array of type/name field descriptions
1235  * @n_fields: The number of field descriptions contained in the fields array
1236  *
1237  * Generate a synthetic event command to be executed by
1238  * synth_event_gen_cmd_end().  This function can be used to generate
1239  * the complete command or only the first part of it; in the latter
1240  * case, synth_event_add_field(), synth_event_add_field_str(), or
1241  * synth_event_add_fields() can be used to add more fields following
1242  * this.
1243  *
1244  * The event fields that will be defined for the event should be
1245  * passed in as an array of struct synth_field_desc, and the number of
1246  * elements in the array passed in as n_fields.  Field ordering will
1247  * retain the ordering given in the fields array.
1248  *
1249  * See synth_field_size() for available types. If field_name contains
1250  * [n] the field is considered to be an array.
1251  *
1252  * Return: 0 if successful, error otherwise.
1253  */
1254 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1255                                     struct module *mod,
1256                                     struct synth_field_desc *fields,
1257                                     unsigned int n_fields)
1258 {
1259         struct dynevent_arg arg;
1260         unsigned int i;
1261         int ret = 0;
1262
1263         cmd->event_name = name;
1264         cmd->private_data = mod;
1265
1266         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1267                 return -EINVAL;
1268
1269         if (n_fields > SYNTH_FIELDS_MAX)
1270                 return -EINVAL;
1271
1272         dynevent_arg_init(&arg, 0);
1273         arg.str = name;
1274         ret = dynevent_arg_add(cmd, &arg, NULL);
1275         if (ret)
1276                 return ret;
1277
1278         for (i = 0; i < n_fields; i++) {
1279                 if (fields[i].type == NULL || fields[i].name == NULL)
1280                         return -EINVAL;
1281
1282                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1283                 if (ret)
1284                         break;
1285         }
1286
1287         return ret;
1288 }
1289 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1290
1291 static int __create_synth_event(const char *name, const char *raw_fields)
1292 {
1293         char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1294         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1295         int consumed, cmd_version = 1, n_fields_this_loop;
1296         int i, argc, n_fields = 0, ret = 0;
1297         struct synth_event *event = NULL;
1298
1299         /*
1300          * Argument syntax:
1301          *  - Add synthetic event: <event_name> field[;field] ...
1302          *  - Remove synthetic event: !<event_name> field[;field] ...
1303          *      where 'field' = type field_name
1304          */
1305
1306         if (name[0] == '\0') {
1307                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1308                 return -EINVAL;
1309         }
1310
1311         if (!is_good_name(name)) {
1312                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1313                 return -EINVAL;
1314         }
1315
1316         mutex_lock(&event_mutex);
1317
1318         event = find_synth_event(name);
1319         if (event) {
1320                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1321                 ret = -EEXIST;
1322                 goto err;
1323         }
1324
1325         tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1326         if (!tmp_fields) {
1327                 ret = -ENOMEM;
1328                 goto err;
1329         }
1330
1331         while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1332                 argv = argv_split(GFP_KERNEL, field_str, &argc);
1333                 if (!argv) {
1334                         ret = -ENOMEM;
1335                         goto err;
1336                 }
1337
1338                 if (!argc) {
1339                         argv_free(argv);
1340                         continue;
1341                 }
1342
1343                 n_fields_this_loop = 0;
1344                 consumed = 0;
1345                 while (argc > consumed) {
1346                         int field_version;
1347
1348                         field = parse_synth_field(argc - consumed,
1349                                                   argv + consumed, &consumed,
1350                                                   &field_version);
1351                         if (IS_ERR(field)) {
1352                                 ret = PTR_ERR(field);
1353                                 goto err_free_arg;
1354                         }
1355
1356                         /*
1357                          * Track the highest version of any field we
1358                          * found in the command.
1359                          */
1360                         if (field_version > cmd_version)
1361                                 cmd_version = field_version;
1362
1363                         /*
1364                          * Now sort out what is and isn't valid for
1365                          * each supported version.
1366                          *
1367                          * If we see more than 1 field per loop, it
1368                          * means we have multiple fields between
1369                          * semicolons, and that's something we no
1370                          * longer support in a version 2 or greater
1371                          * command.
1372                          */
1373                         if (cmd_version > 1 && n_fields_this_loop >= 1) {
1374                                 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1375                                 ret = -EINVAL;
1376                                 goto err_free_arg;
1377                         }
1378
1379                         if (n_fields == SYNTH_FIELDS_MAX) {
1380                                 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1381                                 ret = -EINVAL;
1382                                 goto err_free_arg;
1383                         }
1384                         fields[n_fields++] = field;
1385
1386                         n_fields_this_loop++;
1387                 }
1388                 argv_free(argv);
1389
1390                 if (consumed < argc) {
1391                         synth_err(SYNTH_ERR_INVALID_CMD, 0);
1392                         ret = -EINVAL;
1393                         goto err;
1394                 }
1395
1396         }
1397
1398         if (n_fields == 0) {
1399                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1400                 ret = -EINVAL;
1401                 goto err;
1402         }
1403
1404         event = alloc_synth_event(name, n_fields, fields);
1405         if (IS_ERR(event)) {
1406                 ret = PTR_ERR(event);
1407                 event = NULL;
1408                 goto err;
1409         }
1410         ret = register_synth_event(event);
1411         if (!ret)
1412                 dyn_event_add(&event->devent, &event->call);
1413         else
1414                 free_synth_event(event);
1415  out:
1416         mutex_unlock(&event_mutex);
1417
1418         kfree(saved_fields);
1419
1420         return ret;
1421  err_free_arg:
1422         argv_free(argv);
1423  err:
1424         for (i = 0; i < n_fields; i++)
1425                 free_synth_field(fields[i]);
1426
1427         goto out;
1428 }
1429
1430 /**
1431  * synth_event_create - Create a new synthetic event
1432  * @name: The name of the new synthetic event
1433  * @fields: An array of type/name field descriptions
1434  * @n_fields: The number of field descriptions contained in the fields array
1435  * @mod: The module creating the event, NULL if not created from a module
1436  *
1437  * Create a new synthetic event with the given name under the
1438  * trace/events/synthetic/ directory.  The event fields that will be
1439  * defined for the event should be passed in as an array of struct
1440  * synth_field_desc, and the number elements in the array passed in as
1441  * n_fields. Field ordering will retain the ordering given in the
1442  * fields array.
1443  *
1444  * If the new synthetic event is being created from a module, the mod
1445  * param must be non-NULL.  This will ensure that the trace buffer
1446  * won't contain unreadable events.
1447  *
1448  * The new synth event should be deleted using synth_event_delete()
1449  * function.  The new synthetic event can be generated from modules or
1450  * other kernel code using trace_synth_event() and related functions.
1451  *
1452  * Return: 0 if successful, error otherwise.
1453  */
1454 int synth_event_create(const char *name, struct synth_field_desc *fields,
1455                        unsigned int n_fields, struct module *mod)
1456 {
1457         struct dynevent_cmd cmd;
1458         char *buf;
1459         int ret;
1460
1461         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1462         if (!buf)
1463                 return -ENOMEM;
1464
1465         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1466
1467         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1468                                               fields, n_fields);
1469         if (ret)
1470                 goto out;
1471
1472         ret = synth_event_gen_cmd_end(&cmd);
1473  out:
1474         kfree(buf);
1475
1476         return ret;
1477 }
1478 EXPORT_SYMBOL_GPL(synth_event_create);
1479
1480 static int destroy_synth_event(struct synth_event *se)
1481 {
1482         int ret;
1483
1484         if (se->ref)
1485                 return -EBUSY;
1486
1487         if (trace_event_dyn_busy(&se->call))
1488                 return -EBUSY;
1489
1490         ret = unregister_synth_event(se);
1491         if (!ret) {
1492                 dyn_event_remove(&se->devent);
1493                 free_synth_event(se);
1494         }
1495
1496         return ret;
1497 }
1498
1499 /**
1500  * synth_event_delete - Delete a synthetic event
1501  * @event_name: The name of the new synthetic event
1502  *
1503  * Delete a synthetic event that was created with synth_event_create().
1504  *
1505  * Return: 0 if successful, error otherwise.
1506  */
1507 int synth_event_delete(const char *event_name)
1508 {
1509         struct synth_event *se = NULL;
1510         struct module *mod = NULL;
1511         int ret = -ENOENT;
1512
1513         mutex_lock(&event_mutex);
1514         se = find_synth_event(event_name);
1515         if (se) {
1516                 mod = se->mod;
1517                 ret = destroy_synth_event(se);
1518         }
1519         mutex_unlock(&event_mutex);
1520
1521         if (mod) {
1522                 /*
1523                  * It is safest to reset the ring buffer if the module
1524                  * being unloaded registered any events that were
1525                  * used. The only worry is if a new module gets
1526                  * loaded, and takes on the same id as the events of
1527                  * this module. When printing out the buffer, traced
1528                  * events left over from this module may be passed to
1529                  * the new module events and unexpected results may
1530                  * occur.
1531                  */
1532                 tracing_reset_all_online_cpus();
1533         }
1534
1535         return ret;
1536 }
1537 EXPORT_SYMBOL_GPL(synth_event_delete);
1538
1539 static int check_command(const char *raw_command)
1540 {
1541         char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1542         int argc, ret = 0;
1543
1544         cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1545         if (!cmd)
1546                 return -ENOMEM;
1547
1548         name_and_field = strsep(&cmd, ";");
1549         if (!name_and_field) {
1550                 ret = -EINVAL;
1551                 goto free;
1552         }
1553
1554         if (name_and_field[0] == '!')
1555                 goto free;
1556
1557         argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1558         if (!argv) {
1559                 ret = -ENOMEM;
1560                 goto free;
1561         }
1562         argv_free(argv);
1563
1564         if (argc < 3)
1565                 ret = -EINVAL;
1566 free:
1567         kfree(saved_cmd);
1568
1569         return ret;
1570 }
1571
1572 static int create_or_delete_synth_event(const char *raw_command)
1573 {
1574         char *name = NULL, *fields, *p;
1575         int ret = 0;
1576
1577         raw_command = skip_spaces(raw_command);
1578         if (raw_command[0] == '\0')
1579                 return ret;
1580
1581         last_cmd_set(raw_command);
1582
1583         ret = check_command(raw_command);
1584         if (ret) {
1585                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1586                 return ret;
1587         }
1588
1589         p = strpbrk(raw_command, " \t");
1590         if (!p && raw_command[0] != '!') {
1591                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1592                 ret = -EINVAL;
1593                 goto free;
1594         }
1595
1596         name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1597         if (!name)
1598                 return -ENOMEM;
1599
1600         if (name[0] == '!') {
1601                 ret = synth_event_delete(name + 1);
1602                 goto free;
1603         }
1604
1605         fields = skip_spaces(p);
1606
1607         ret = __create_synth_event(name, fields);
1608 free:
1609         kfree(name);
1610
1611         return ret;
1612 }
1613
1614 static int synth_event_run_command(struct dynevent_cmd *cmd)
1615 {
1616         struct synth_event *se;
1617         int ret;
1618
1619         ret = create_or_delete_synth_event(cmd->seq.buffer);
1620         if (ret)
1621                 return ret;
1622
1623         se = find_synth_event(cmd->event_name);
1624         if (WARN_ON(!se))
1625                 return -ENOENT;
1626
1627         se->mod = cmd->private_data;
1628
1629         return ret;
1630 }
1631
1632 /**
1633  * synth_event_cmd_init - Initialize a synthetic event command object
1634  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1635  * @buf: A pointer to the buffer used to build the command
1636  * @maxlen: The length of the buffer passed in @buf
1637  *
1638  * Initialize a synthetic event command object.  Use this before
1639  * calling any of the other dyenvent_cmd functions.
1640  */
1641 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1642 {
1643         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1644                           synth_event_run_command);
1645 }
1646 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1647
1648 static inline int
1649 __synth_event_trace_init(struct trace_event_file *file,
1650                          struct synth_event_trace_state *trace_state)
1651 {
1652         int ret = 0;
1653
1654         memset(trace_state, '\0', sizeof(*trace_state));
1655
1656         /*
1657          * Normal event tracing doesn't get called at all unless the
1658          * ENABLED bit is set (which attaches the probe thus allowing
1659          * this code to be called, etc).  Because this is called
1660          * directly by the user, we don't have that but we still need
1661          * to honor not logging when disabled.  For the iterated
1662          * trace case, we save the enabled state upon start and just
1663          * ignore the following data calls.
1664          */
1665         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1666             trace_trigger_soft_disabled(file)) {
1667                 trace_state->disabled = true;
1668                 ret = -ENOENT;
1669                 goto out;
1670         }
1671
1672         trace_state->event = file->event_call->data;
1673 out:
1674         return ret;
1675 }
1676
1677 static inline int
1678 __synth_event_trace_start(struct trace_event_file *file,
1679                           struct synth_event_trace_state *trace_state,
1680                           int dynamic_fields_size)
1681 {
1682         int entry_size, fields_size = 0;
1683         int ret = 0;
1684
1685         fields_size = trace_state->event->n_u64 * sizeof(u64);
1686         fields_size += dynamic_fields_size;
1687
1688         /*
1689          * Avoid ring buffer recursion detection, as this event
1690          * is being performed within another event.
1691          */
1692         trace_state->buffer = file->tr->array_buffer.buffer;
1693         ring_buffer_nest_start(trace_state->buffer);
1694
1695         entry_size = sizeof(*trace_state->entry) + fields_size;
1696         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1697                                                         file,
1698                                                         entry_size);
1699         if (!trace_state->entry) {
1700                 ring_buffer_nest_end(trace_state->buffer);
1701                 ret = -EINVAL;
1702         }
1703
1704         return ret;
1705 }
1706
1707 static inline void
1708 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1709 {
1710         trace_event_buffer_commit(&trace_state->fbuffer);
1711
1712         ring_buffer_nest_end(trace_state->buffer);
1713 }
1714
1715 /**
1716  * synth_event_trace - Trace a synthetic event
1717  * @file: The trace_event_file representing the synthetic event
1718  * @n_vals: The number of values in vals
1719  * @args: Variable number of args containing the event values
1720  *
1721  * Trace a synthetic event using the values passed in the variable
1722  * argument list.
1723  *
1724  * The argument list should be a list 'n_vals' u64 values.  The number
1725  * of vals must match the number of field in the synthetic event, and
1726  * must be in the same order as the synthetic event fields.
1727  *
1728  * All vals should be cast to u64, and string vals are just pointers
1729  * to strings, cast to u64.  Strings will be copied into space
1730  * reserved in the event for the string, using these pointers.
1731  *
1732  * Return: 0 on success, err otherwise.
1733  */
1734 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1735 {
1736         unsigned int i, n_u64, len, data_size = 0;
1737         struct synth_event_trace_state state;
1738         va_list args;
1739         int ret;
1740
1741         ret = __synth_event_trace_init(file, &state);
1742         if (ret) {
1743                 if (ret == -ENOENT)
1744                         ret = 0; /* just disabled, not really an error */
1745                 return ret;
1746         }
1747
1748         if (state.event->n_dynamic_fields) {
1749                 va_start(args, n_vals);
1750
1751                 for (i = 0; i < state.event->n_fields; i++) {
1752                         u64 val = va_arg(args, u64);
1753
1754                         if (state.event->fields[i]->is_string &&
1755                             state.event->fields[i]->is_dynamic) {
1756                                 char *str_val = (char *)(long)val;
1757
1758                                 data_size += strlen(str_val) + 1;
1759                         }
1760                 }
1761
1762                 va_end(args);
1763         }
1764
1765         ret = __synth_event_trace_start(file, &state, data_size);
1766         if (ret)
1767                 return ret;
1768
1769         if (n_vals != state.event->n_fields) {
1770                 ret = -EINVAL;
1771                 goto out;
1772         }
1773
1774         data_size = 0;
1775
1776         va_start(args, n_vals);
1777         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1778                 u64 val;
1779
1780                 val = va_arg(args, u64);
1781
1782                 if (state.event->fields[i]->is_string) {
1783                         char *str_val = (char *)(long)val;
1784
1785                         len = trace_string(state.entry, state.event, str_val,
1786                                            state.event->fields[i]->is_dynamic,
1787                                            data_size, &n_u64);
1788                         data_size += len; /* only dynamic string increments */
1789                 } else {
1790                         struct synth_field *field = state.event->fields[i];
1791
1792                         switch (field->size) {
1793                         case 1:
1794                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1795                                 break;
1796
1797                         case 2:
1798                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1799                                 break;
1800
1801                         case 4:
1802                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1803                                 break;
1804
1805                         default:
1806                                 state.entry->fields[n_u64] = val;
1807                                 break;
1808                         }
1809                         n_u64++;
1810                 }
1811         }
1812         va_end(args);
1813 out:
1814         __synth_event_trace_end(&state);
1815
1816         return ret;
1817 }
1818 EXPORT_SYMBOL_GPL(synth_event_trace);
1819
1820 /**
1821  * synth_event_trace_array - Trace a synthetic event from an array
1822  * @file: The trace_event_file representing the synthetic event
1823  * @vals: Array of values
1824  * @n_vals: The number of values in vals
1825  *
1826  * Trace a synthetic event using the values passed in as 'vals'.
1827  *
1828  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1829  * vals must match the number of field in the synthetic event, and
1830  * must be in the same order as the synthetic event fields.
1831  *
1832  * All vals should be cast to u64, and string vals are just pointers
1833  * to strings, cast to u64.  Strings will be copied into space
1834  * reserved in the event for the string, using these pointers.
1835  *
1836  * Return: 0 on success, err otherwise.
1837  */
1838 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1839                             unsigned int n_vals)
1840 {
1841         unsigned int i, n_u64, field_pos, len, data_size = 0;
1842         struct synth_event_trace_state state;
1843         char *str_val;
1844         int ret;
1845
1846         ret = __synth_event_trace_init(file, &state);
1847         if (ret) {
1848                 if (ret == -ENOENT)
1849                         ret = 0; /* just disabled, not really an error */
1850                 return ret;
1851         }
1852
1853         if (state.event->n_dynamic_fields) {
1854                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1855                         field_pos = state.event->dynamic_fields[i]->field_pos;
1856                         str_val = (char *)(long)vals[field_pos];
1857                         len = strlen(str_val) + 1;
1858                         data_size += len;
1859                 }
1860         }
1861
1862         ret = __synth_event_trace_start(file, &state, data_size);
1863         if (ret)
1864                 return ret;
1865
1866         if (n_vals != state.event->n_fields) {
1867                 ret = -EINVAL;
1868                 goto out;
1869         }
1870
1871         data_size = 0;
1872
1873         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1874                 if (state.event->fields[i]->is_string) {
1875                         char *str_val = (char *)(long)vals[i];
1876
1877                         len = trace_string(state.entry, state.event, str_val,
1878                                            state.event->fields[i]->is_dynamic,
1879                                            data_size, &n_u64);
1880                         data_size += len; /* only dynamic string increments */
1881                 } else {
1882                         struct synth_field *field = state.event->fields[i];
1883                         u64 val = vals[i];
1884
1885                         switch (field->size) {
1886                         case 1:
1887                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1888                                 break;
1889
1890                         case 2:
1891                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1892                                 break;
1893
1894                         case 4:
1895                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1896                                 break;
1897
1898                         default:
1899                                 state.entry->fields[n_u64] = val;
1900                                 break;
1901                         }
1902                         n_u64++;
1903                 }
1904         }
1905 out:
1906         __synth_event_trace_end(&state);
1907
1908         return ret;
1909 }
1910 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1911
1912 /**
1913  * synth_event_trace_start - Start piecewise synthetic event trace
1914  * @file: The trace_event_file representing the synthetic event
1915  * @trace_state: A pointer to object tracking the piecewise trace state
1916  *
1917  * Start the trace of a synthetic event field-by-field rather than all
1918  * at once.
1919  *
1920  * This function 'opens' an event trace, which means space is reserved
1921  * for the event in the trace buffer, after which the event's
1922  * individual field values can be set through either
1923  * synth_event_add_next_val() or synth_event_add_val().
1924  *
1925  * A pointer to a trace_state object is passed in, which will keep
1926  * track of the current event trace state until the event trace is
1927  * closed (and the event finally traced) using
1928  * synth_event_trace_end().
1929  *
1930  * Note that synth_event_trace_end() must be called after all values
1931  * have been added for each event trace, regardless of whether adding
1932  * all field values succeeded or not.
1933  *
1934  * Note also that for a given event trace, all fields must be added
1935  * using either synth_event_add_next_val() or synth_event_add_val()
1936  * but not both together or interleaved.
1937  *
1938  * Return: 0 on success, err otherwise.
1939  */
1940 int synth_event_trace_start(struct trace_event_file *file,
1941                             struct synth_event_trace_state *trace_state)
1942 {
1943         int ret;
1944
1945         if (!trace_state)
1946                 return -EINVAL;
1947
1948         ret = __synth_event_trace_init(file, trace_state);
1949         if (ret) {
1950                 if (ret == -ENOENT)
1951                         ret = 0; /* just disabled, not really an error */
1952                 return ret;
1953         }
1954
1955         if (trace_state->event->n_dynamic_fields)
1956                 return -ENOTSUPP;
1957
1958         ret = __synth_event_trace_start(file, trace_state, 0);
1959
1960         return ret;
1961 }
1962 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1963
1964 static int __synth_event_add_val(const char *field_name, u64 val,
1965                                  struct synth_event_trace_state *trace_state)
1966 {
1967         struct synth_field *field = NULL;
1968         struct synth_trace_event *entry;
1969         struct synth_event *event;
1970         int i, ret = 0;
1971
1972         if (!trace_state) {
1973                 ret = -EINVAL;
1974                 goto out;
1975         }
1976
1977         /* can't mix add_next_synth_val() with add_synth_val() */
1978         if (field_name) {
1979                 if (trace_state->add_next) {
1980                         ret = -EINVAL;
1981                         goto out;
1982                 }
1983                 trace_state->add_name = true;
1984         } else {
1985                 if (trace_state->add_name) {
1986                         ret = -EINVAL;
1987                         goto out;
1988                 }
1989                 trace_state->add_next = true;
1990         }
1991
1992         if (trace_state->disabled)
1993                 goto out;
1994
1995         event = trace_state->event;
1996         if (trace_state->add_name) {
1997                 for (i = 0; i < event->n_fields; i++) {
1998                         field = event->fields[i];
1999                         if (strcmp(field->name, field_name) == 0)
2000                                 break;
2001                 }
2002                 if (!field) {
2003                         ret = -EINVAL;
2004                         goto out;
2005                 }
2006         } else {
2007                 if (trace_state->cur_field >= event->n_fields) {
2008                         ret = -EINVAL;
2009                         goto out;
2010                 }
2011                 field = event->fields[trace_state->cur_field++];
2012         }
2013
2014         entry = trace_state->entry;
2015         if (field->is_string) {
2016                 char *str_val = (char *)(long)val;
2017                 char *str_field;
2018
2019                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
2020                         ret = -EINVAL;
2021                         goto out;
2022                 }
2023
2024                 if (!str_val) {
2025                         ret = -EINVAL;
2026                         goto out;
2027                 }
2028
2029                 str_field = (char *)&entry->fields[field->offset];
2030                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
2031         } else {
2032                 switch (field->size) {
2033                 case 1:
2034                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
2035                         break;
2036
2037                 case 2:
2038                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
2039                         break;
2040
2041                 case 4:
2042                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
2043                         break;
2044
2045                 default:
2046                         trace_state->entry->fields[field->offset] = val;
2047                         break;
2048                 }
2049         }
2050  out:
2051         return ret;
2052 }
2053
2054 /**
2055  * synth_event_add_next_val - Add the next field's value to an open synth trace
2056  * @val: The value to set the next field to
2057  * @trace_state: A pointer to object tracking the piecewise trace state
2058  *
2059  * Set the value of the next field in an event that's been opened by
2060  * synth_event_trace_start().
2061  *
2062  * The val param should be the value cast to u64.  If the value points
2063  * to a string, the val param should be a char * cast to u64.
2064  *
2065  * This function assumes all the fields in an event are to be set one
2066  * after another - successive calls to this function are made, one for
2067  * each field, in the order of the fields in the event, until all
2068  * fields have been set.  If you'd rather set each field individually
2069  * without regard to ordering, synth_event_add_val() can be used
2070  * instead.
2071  *
2072  * Note however that synth_event_add_next_val() and
2073  * synth_event_add_val() can't be intermixed for a given event trace -
2074  * one or the other but not both can be used at the same time.
2075  *
2076  * Note also that synth_event_trace_end() must be called after all
2077  * values have been added for each event trace, regardless of whether
2078  * adding all field values succeeded or not.
2079  *
2080  * Return: 0 on success, err otherwise.
2081  */
2082 int synth_event_add_next_val(u64 val,
2083                              struct synth_event_trace_state *trace_state)
2084 {
2085         return __synth_event_add_val(NULL, val, trace_state);
2086 }
2087 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
2088
2089 /**
2090  * synth_event_add_val - Add a named field's value to an open synth trace
2091  * @field_name: The name of the synthetic event field value to set
2092  * @val: The value to set the named field to
2093  * @trace_state: A pointer to object tracking the piecewise trace state
2094  *
2095  * Set the value of the named field in an event that's been opened by
2096  * synth_event_trace_start().
2097  *
2098  * The val param should be the value cast to u64.  If the value points
2099  * to a string, the val param should be a char * cast to u64.
2100  *
2101  * This function looks up the field name, and if found, sets the field
2102  * to the specified value.  This lookup makes this function more
2103  * expensive than synth_event_add_next_val(), so use that or the
2104  * none-piecewise synth_event_trace() instead if efficiency is more
2105  * important.
2106  *
2107  * Note however that synth_event_add_next_val() and
2108  * synth_event_add_val() can't be intermixed for a given event trace -
2109  * one or the other but not both can be used at the same time.
2110  *
2111  * Note also that synth_event_trace_end() must be called after all
2112  * values have been added for each event trace, regardless of whether
2113  * adding all field values succeeded or not.
2114  *
2115  * Return: 0 on success, err otherwise.
2116  */
2117 int synth_event_add_val(const char *field_name, u64 val,
2118                         struct synth_event_trace_state *trace_state)
2119 {
2120         return __synth_event_add_val(field_name, val, trace_state);
2121 }
2122 EXPORT_SYMBOL_GPL(synth_event_add_val);
2123
2124 /**
2125  * synth_event_trace_end - End piecewise synthetic event trace
2126  * @trace_state: A pointer to object tracking the piecewise trace state
2127  *
2128  * End the trace of a synthetic event opened by
2129  * synth_event_trace__start().
2130  *
2131  * This function 'closes' an event trace, which basically means that
2132  * it commits the reserved event and cleans up other loose ends.
2133  *
2134  * A pointer to a trace_state object is passed in, which will keep
2135  * track of the current event trace state opened with
2136  * synth_event_trace_start().
2137  *
2138  * Note that this function must be called after all values have been
2139  * added for each event trace, regardless of whether adding all field
2140  * values succeeded or not.
2141  *
2142  * Return: 0 on success, err otherwise.
2143  */
2144 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2145 {
2146         if (!trace_state)
2147                 return -EINVAL;
2148
2149         __synth_event_trace_end(trace_state);
2150
2151         return 0;
2152 }
2153 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2154
2155 static int create_synth_event(const char *raw_command)
2156 {
2157         char *fields, *p;
2158         const char *name;
2159         int len, ret = 0;
2160
2161         raw_command = skip_spaces(raw_command);
2162         if (raw_command[0] == '\0')
2163                 return ret;
2164
2165         last_cmd_set(raw_command);
2166
2167         name = raw_command;
2168
2169         /* Don't try to process if not our system */
2170         if (name[0] != 's' || name[1] != ':')
2171                 return -ECANCELED;
2172         name += 2;
2173
2174         p = strpbrk(raw_command, " \t");
2175         if (!p) {
2176                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2177                 return -EINVAL;
2178         }
2179
2180         fields = skip_spaces(p);
2181
2182         /* This interface accepts group name prefix */
2183         if (strchr(name, '/')) {
2184                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2185                 if (len == 0) {
2186                         synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2187                         return -EINVAL;
2188                 }
2189                 name += len;
2190         }
2191
2192         len = name - raw_command;
2193
2194         ret = check_command(raw_command + len);
2195         if (ret) {
2196                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2197                 return ret;
2198         }
2199
2200         name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2201         if (!name)
2202                 return -ENOMEM;
2203
2204         ret = __create_synth_event(name, fields);
2205
2206         kfree(name);
2207
2208         return ret;
2209 }
2210
2211 static int synth_event_release(struct dyn_event *ev)
2212 {
2213         struct synth_event *event = to_synth_event(ev);
2214         int ret;
2215
2216         if (event->ref)
2217                 return -EBUSY;
2218
2219         if (trace_event_dyn_busy(&event->call))
2220                 return -EBUSY;
2221
2222         ret = unregister_synth_event(event);
2223         if (ret)
2224                 return ret;
2225
2226         dyn_event_remove(ev);
2227         free_synth_event(event);
2228         return 0;
2229 }
2230
2231 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2232 {
2233         struct synth_field *field;
2234         unsigned int i;
2235         char *type, *t;
2236
2237         seq_printf(m, "%s\t", event->name);
2238
2239         for (i = 0; i < event->n_fields; i++) {
2240                 field = event->fields[i];
2241
2242                 type = field->type;
2243                 t = strstr(type, "__data_loc");
2244                 if (t) { /* __data_loc belongs in format but not event desc */
2245                         t += sizeof("__data_loc");
2246                         type = t;
2247                 }
2248
2249                 /* parameter values */
2250                 seq_printf(m, "%s %s%s", type, field->name,
2251                            i == event->n_fields - 1 ? "" : "; ");
2252         }
2253
2254         seq_putc(m, '\n');
2255
2256         return 0;
2257 }
2258
2259 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2260 {
2261         struct synth_event *event = to_synth_event(ev);
2262
2263         seq_printf(m, "s:%s/", event->class.system);
2264
2265         return __synth_event_show(m, event);
2266 }
2267
2268 static int synth_events_seq_show(struct seq_file *m, void *v)
2269 {
2270         struct dyn_event *ev = v;
2271
2272         if (!is_synth_event(ev))
2273                 return 0;
2274
2275         return __synth_event_show(m, to_synth_event(ev));
2276 }
2277
2278 static const struct seq_operations synth_events_seq_op = {
2279         .start  = dyn_event_seq_start,
2280         .next   = dyn_event_seq_next,
2281         .stop   = dyn_event_seq_stop,
2282         .show   = synth_events_seq_show,
2283 };
2284
2285 static int synth_events_open(struct inode *inode, struct file *file)
2286 {
2287         int ret;
2288
2289         ret = security_locked_down(LOCKDOWN_TRACEFS);
2290         if (ret)
2291                 return ret;
2292
2293         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2294                 ret = dyn_events_release_all(&synth_event_ops);
2295                 if (ret < 0)
2296                         return ret;
2297         }
2298
2299         return seq_open(file, &synth_events_seq_op);
2300 }
2301
2302 static ssize_t synth_events_write(struct file *file,
2303                                   const char __user *buffer,
2304                                   size_t count, loff_t *ppos)
2305 {
2306         return trace_parse_run_command(file, buffer, count, ppos,
2307                                        create_or_delete_synth_event);
2308 }
2309
2310 static const struct file_operations synth_events_fops = {
2311         .open           = synth_events_open,
2312         .write          = synth_events_write,
2313         .read           = seq_read,
2314         .llseek         = seq_lseek,
2315         .release        = seq_release,
2316 };
2317
2318 /*
2319  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2320  * events in postcore_initcall without tracefs.
2321  */
2322 static __init int trace_events_synth_init_early(void)
2323 {
2324         int err = 0;
2325
2326         err = dyn_event_register(&synth_event_ops);
2327         if (err)
2328                 pr_warn("Could not register synth_event_ops\n");
2329
2330         return err;
2331 }
2332 core_initcall(trace_events_synth_init_early);
2333
2334 static __init int trace_events_synth_init(void)
2335 {
2336         struct dentry *entry = NULL;
2337         int err = 0;
2338         err = tracing_init_dentry();
2339         if (err)
2340                 goto err;
2341
2342         entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
2343                                     NULL, NULL, &synth_events_fops);
2344         if (!entry) {
2345                 err = -ENODEV;
2346                 goto err;
2347         }
2348
2349         return err;
2350  err:
2351         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2352
2353         return err;
2354 }
2355
2356 fs_initcall(trace_events_synth_init);