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