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         union trace_synth_field 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, union trace_synth_field *val, char *space)
 325 {
 326         switch (size) {
 327         case 1:
 328                 trace_seq_printf(s, print_fmt, name, val->as_u8, space);
 329                 break;
 330
 331         case 2:
 332                 trace_seq_printf(s, print_fmt, name, val->as_u16, space);
 333                 break;
 334
 335         case 4:
 336                 trace_seq_printf(s, print_fmt, name, val->as_u32, space);
 337                 break;
 338
 339         default:
 340                 trace_seq_printf(s, print_fmt, name, val->as_u64, 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, j, 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                                 union trace_synth_field *data = &entry->fields[n_u64];
 378
 379                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 380                                                  STR_VAR_LEN_MAX,
 381                                                  (char *)entry + data->as_dynamic.offset,
 382                                                  i == se->n_fields - 1 ? "" : " ");
 383                                 n_u64++;
 384                         } else {
 385                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 386                                                  STR_VAR_LEN_MAX,
 387                                                  (char *)&entry->fields[n_u64].as_u64,
 388                                                  i == se->n_fields - 1 ? "" : " ");
 389                                 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 390                         }
 391                 } else if (se->fields[i]->is_stack) {
 392                         union trace_synth_field *data = &entry->fields[n_u64];
 393                         unsigned long *p = (void *)entry + data->as_dynamic.offset;
 394
 395                         trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
 396                         for (j = 1; j < data->as_dynamic.len / sizeof(long); j++)
 397                                 trace_seq_printf(s, "=> %pS\n", (void *)p[j]);
 398                         n_u64++;
 399                 } else {
 400                         struct trace_print_flags __flags[] = {
 401                             __def_gfpflag_names, {-1, NULL} };
 402                         char *space = (i == se->n_fields - 1 ? "" : " ");
 403
 404                         print_synth_event_num_val(s, print_fmt,
 405                                                   se->fields[i]->name,
 406                                                   se->fields[i]->size,
 407                                                   &entry->fields[n_u64],
 408                                                   space);
 409
 410                         if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
 411                                 trace_seq_puts(s, " (");
 412                                 trace_print_flags_seq(s, "|",
 413                                                       entry->fields[n_u64].as_u64,
 414                                                       __flags);
 415                                 trace_seq_putc(s, ')');
 416                         }
 417                         n_u64++;
 418                 }
 419         }
 420 end:
 421         trace_seq_putc(s, '\n');
 422
 423         return trace_handle_return(s);
 424 }
 425
 426 static struct trace_event_functions synth_event_funcs = {
 427         .trace          = print_synth_event
 428 };
 429
 430 static unsigned int trace_string(struct synth_trace_event *entry,
 431                                  struct synth_event *event,
 432                                  char *str_val,
 433                                  bool is_dynamic,
 434                                  unsigned int data_size,
 435                                  unsigned int *n_u64)
 436 {
 437         unsigned int len = 0;
 438         char *str_field;
 439         int ret;
 440
 441         if (is_dynamic) {
 442                 union trace_synth_field *data = &entry->fields[*n_u64];
 443
 444                 data->as_dynamic.offset = struct_size(entry, fields, event->n_u64) + data_size;
 445                 data->as_dynamic.len = fetch_store_strlen((unsigned long)str_val);
 446
 447                 ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
 448
 449                 (*n_u64)++;
 450         } else {
 451                 str_field = (char *)&entry->fields[*n_u64].as_u64;
 452
 453 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 454                 if ((unsigned long)str_val < TASK_SIZE)
 455                         ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
 456                 else
 457 #endif
 458                         ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
 459
 460                 if (ret < 0)
 461                         strcpy(str_field, FAULT_STRING);
 462
 463                 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
 464         }
 465
 466         return len;
 467 }
 468
 469 static unsigned int trace_stack(struct synth_trace_event *entry,
 470                                  struct synth_event *event,
 471                                  long *stack,
 472                                  unsigned int data_size,
 473                                  unsigned int *n_u64)
 474 {
 475         union trace_synth_field *data = &entry->fields[*n_u64];
 476         unsigned int len;
 477         u32 data_offset;
 478         void *data_loc;
 479
 480         data_offset = struct_size(entry, fields, event->n_u64);
 481         data_offset += data_size;
 482
 483         for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
 484                 if (!stack[len])
 485                         break;
 486         }
 487
 488         len *= sizeof(long);
 489
 490         /* Find the dynamic section to copy the stack into. */
 491         data_loc = (void *)entry + data_offset;
 492         memcpy(data_loc, stack, len);
 493
 494         /* Fill in the field that holds the offset/len combo */
 495
 496         data->as_dynamic.offset = data_offset;
 497         data->as_dynamic.len = len;
 498
 499         (*n_u64)++;
 500
 501         return len;
 502 }
 503
 504 static notrace void trace_event_raw_event_synth(void *__data,
 505                                                 u64 *var_ref_vals,
 506                                                 unsigned int *var_ref_idx)
 507 {
 508         unsigned int i, n_u64, val_idx, len, data_size = 0;
 509         struct trace_event_file *trace_file = __data;
 510         struct synth_trace_event *entry;
 511         struct trace_event_buffer fbuffer;
 512         struct trace_buffer *buffer;
 513         struct synth_event *event;
 514         int fields_size = 0;
 515
 516         event = trace_file->event_call->data;
 517
 518         if (trace_trigger_soft_disabled(trace_file))
 519                 return;
 520
 521         fields_size = event->n_u64 * sizeof(u64);
 522
 523         for (i = 0; i < event->n_dynamic_fields; i++) {
 524                 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
 525                 char *str_val;
 526
 527                 val_idx = var_ref_idx[field_pos];
 528                 str_val = (char *)(long)var_ref_vals[val_idx];
 529
 530                 if (event->dynamic_fields[i]->is_stack) {
 531                         /* reserve one extra element for size */
 532                         len = *((unsigned long *)str_val) + 1;
 533                         len *= sizeof(unsigned long);
 534                 } else {
 535                         len = fetch_store_strlen((unsigned long)str_val);
 536                 }
 537
 538                 fields_size += len;
 539         }
 540
 541         /*
 542          * Avoid ring buffer recursion detection, as this event
 543          * is being performed within another event.
 544          */
 545         buffer = trace_file->tr->array_buffer.buffer;
 546         ring_buffer_nest_start(buffer);
 547
 548         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 549                                            sizeof(*entry) + fields_size);
 550         if (!entry)
 551                 goto out;
 552
 553         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 554                 val_idx = var_ref_idx[i];
 555                 if (event->fields[i]->is_string) {
 556                         char *str_val = (char *)(long)var_ref_vals[val_idx];
 557
 558                         len = trace_string(entry, event, str_val,
 559                                            event->fields[i]->is_dynamic,
 560                                            data_size, &n_u64);
 561                         data_size += len; /* only dynamic string increments */
 562                 } else if (event->fields[i]->is_stack) {
 563                         long *stack = (long *)(long)var_ref_vals[val_idx];
 564
 565                         len = trace_stack(entry, event, stack,
 566                                            data_size, &n_u64);
 567                         data_size += len;
 568                 } else {
 569                         struct synth_field *field = event->fields[i];
 570                         u64 val = var_ref_vals[val_idx];
 571
 572                         switch (field->size) {
 573                         case 1:
 574                                 entry->fields[n_u64].as_u8 = (u8)val;
 575                                 break;
 576
 577                         case 2:
 578                                 entry->fields[n_u64].as_u16 = (u16)val;
 579                                 break;
 580
 581                         case 4:
 582                                 entry->fields[n_u64].as_u32 = (u32)val;
 583                                 break;
 584
 585                         default:
 586                                 entry->fields[n_u64].as_u64 = val;
 587                                 break;
 588                         }
 589                         n_u64++;
 590                 }
 591         }
 592
 593         trace_event_buffer_commit(&fbuffer);
 594 out:
 595         ring_buffer_nest_end(buffer);
 596 }
 597
 598 static void free_synth_event_print_fmt(struct trace_event_call *call)
 599 {
 600         if (call) {
 601                 kfree(call->print_fmt);
 602                 call->print_fmt = NULL;
 603         }
 604 }
 605
 606 static int __set_synth_event_print_fmt(struct synth_event *event,
 607                                        char *buf, int len)
 608 {
 609         const char *fmt;
 610         int pos = 0;
 611         int i;
 612
 613         /* When len=0, we just calculate the needed length */
 614 #define LEN_OR_ZERO (len ? len - pos : 0)
 615
 616         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 617         for (i = 0; i < event->n_fields; i++) {
 618                 fmt = synth_field_fmt(event->fields[i]->type);
 619                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 620                                 event->fields[i]->name, fmt,
 621                                 i == event->n_fields - 1 ? "" : ", ");
 622         }
 623         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 624
 625         for (i = 0; i < event->n_fields; i++) {
 626                 if (event->fields[i]->is_string &&
 627                     event->fields[i]->is_dynamic)
 628                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 629                                 ", __get_str(%s)", event->fields[i]->name);
 630                 else if (event->fields[i]->is_stack)
 631                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 632                                 ", __get_stacktrace(%s)", event->fields[i]->name);
 633                 else
 634                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 635                                         ", REC->%s", event->fields[i]->name);
 636         }
 637
 638 #undef LEN_OR_ZERO
 639
 640         /* return the length of print_fmt */
 641         return pos;
 642 }
 643
 644 static int set_synth_event_print_fmt(struct trace_event_call *call)
 645 {
 646         struct synth_event *event = call->data;
 647         char *print_fmt;
 648         int len;
 649
 650         /* First: called with 0 length to calculate the needed length */
 651         len = __set_synth_event_print_fmt(event, NULL, 0);
 652
 653         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 654         if (!print_fmt)
 655                 return -ENOMEM;
 656
 657         /* Second: actually write the @print_fmt */
 658         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 659         call->print_fmt = print_fmt;
 660
 661         return 0;
 662 }
 663
 664 static void free_synth_field(struct synth_field *field)
 665 {
 666         kfree(field->type);
 667         kfree(field->name);
 668         kfree(field);
 669 }
 670
 671 static int check_field_version(const char *prefix, const char *field_type,
 672                                const char *field_name)
 673 {
 674         /*
 675          * For backward compatibility, the old synthetic event command
 676          * format did not require semicolons, and in order to not
 677          * break user space, that old format must still work. If a new
 678          * feature is added, then the format that uses the new feature
 679          * will be required to have semicolons, as nothing that uses
 680          * the old format would be using the new, yet to be created,
 681          * feature. When a new feature is added, this will detect it,
 682          * and return a number greater than 1, and require the format
 683          * to use semicolons.
 684          */
 685         return 1;
 686 }
 687
 688 static struct synth_field *parse_synth_field(int argc, char **argv,
 689                                              int *consumed, int *field_version)
 690 {
 691         const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 692         struct synth_field *field;
 693         int len, ret = -ENOMEM;
 694         struct seq_buf s;
 695         ssize_t size;
 696
 697         if (!strcmp(field_type, "unsigned")) {
 698                 if (argc < 3) {
 699                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 700                         return ERR_PTR(-EINVAL);
 701                 }
 702                 prefix = "unsigned ";
 703                 field_type = argv[1];
 704                 field_name = argv[2];
 705                 *consumed += 3;
 706         } else {
 707                 field_name = argv[1];
 708                 *consumed += 2;
 709         }
 710
 711         if (!field_name) {
 712                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
 713                 return ERR_PTR(-EINVAL);
 714         }
 715
 716         *field_version = check_field_version(prefix, field_type, field_name);
 717
 718         field = kzalloc(sizeof(*field), GFP_KERNEL);
 719         if (!field)
 720                 return ERR_PTR(-ENOMEM);
 721
 722         len = strlen(field_name);
 723         array = strchr(field_name, '[');
 724         if (array)
 725                 len -= strlen(array);
 726
 727         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 728         if (!field->name)
 729                 goto free;
 730
 731         if (!is_good_name(field->name)) {
 732                 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 733                 ret = -EINVAL;
 734                 goto free;
 735         }
 736
 737         len = strlen(field_type) + 1;
 738
 739         if (array)
 740                 len += strlen(array);
 741
 742         if (prefix)
 743                 len += strlen(prefix);
 744
 745         field->type = kzalloc(len, GFP_KERNEL);
 746         if (!field->type)
 747                 goto free;
 748
 749         seq_buf_init(&s, field->type, len);
 750         if (prefix)
 751                 seq_buf_puts(&s, prefix);
 752         seq_buf_puts(&s, field_type);
 753         if (array)
 754                 seq_buf_puts(&s, array);
 755         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 756                 goto free;
 757
 758         s.buffer[s.len] = '\0';
 759
 760         size = synth_field_size(field->type);
 761         if (size < 0) {
 762                 if (array)
 763                         synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
 764                 else
 765                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 766                 ret = -EINVAL;
 767                 goto free;
 768         } else if (size == 0) {
 769                 if (synth_field_is_string(field->type) ||
 770                     synth_field_is_stack(field->type)) {
 771                         char *type;
 772
 773                         len = sizeof("__data_loc ") + strlen(field->type) + 1;
 774                         type = kzalloc(len, GFP_KERNEL);
 775                         if (!type)
 776                                 goto free;
 777
 778                         seq_buf_init(&s, type, len);
 779                         seq_buf_puts(&s, "__data_loc ");
 780                         seq_buf_puts(&s, field->type);
 781
 782                         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 783                                 goto free;
 784                         s.buffer[s.len] = '\0';
 785
 786                         kfree(field->type);
 787                         field->type = type;
 788
 789                         field->is_dynamic = true;
 790                         size = sizeof(u64);
 791                 } else {
 792                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 793                         ret = -EINVAL;
 794                         goto free;
 795                 }
 796         }
 797         field->size = size;
 798
 799         if (synth_field_is_string(field->type))
 800                 field->is_string = true;
 801         else if (synth_field_is_stack(field->type))
 802                 field->is_stack = true;
 803
 804         field->is_signed = synth_field_signed(field->type);
 805  out:
 806         return field;
 807  free:
 808         free_synth_field(field);
 809         field = ERR_PTR(ret);
 810         goto out;
 811 }
 812
 813 static void free_synth_tracepoint(struct tracepoint *tp)
 814 {
 815         if (!tp)
 816                 return;
 817
 818         kfree(tp->name);
 819         kfree(tp);
 820 }
 821
 822 static struct tracepoint *alloc_synth_tracepoint(char *name)
 823 {
 824         struct tracepoint *tp;
 825
 826         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 827         if (!tp)
 828                 return ERR_PTR(-ENOMEM);
 829
 830         tp->name = kstrdup(name, GFP_KERNEL);
 831         if (!tp->name) {
 832                 kfree(tp);
 833                 return ERR_PTR(-ENOMEM);
 834         }
 835
 836         return tp;
 837 }
 838
 839 struct synth_event *find_synth_event(const char *name)
 840 {
 841         struct dyn_event *pos;
 842         struct synth_event *event;
 843
 844         for_each_dyn_event(pos) {
 845                 if (!is_synth_event(pos))
 846                         continue;
 847                 event = to_synth_event(pos);
 848                 if (strcmp(event->name, name) == 0)
 849                         return event;
 850         }
 851
 852         return NULL;
 853 }
 854
 855 static struct trace_event_fields synth_event_fields_array[] = {
 856         { .type = TRACE_FUNCTION_TYPE,
 857           .define_fields = synth_event_define_fields },
 858         {}
 859 };
 860
 861 static int register_synth_event(struct synth_event *event)
 862 {
 863         struct trace_event_call *call = &event->call;
 864         int ret = 0;
 865
 866         event->call.class = &event->class;
 867         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 868         if (!event->class.system) {
 869                 ret = -ENOMEM;
 870                 goto out;
 871         }
 872
 873         event->tp = alloc_synth_tracepoint(event->name);
 874         if (IS_ERR(event->tp)) {
 875                 ret = PTR_ERR(event->tp);
 876                 event->tp = NULL;
 877                 goto out;
 878         }
 879
 880         INIT_LIST_HEAD(&call->class->fields);
 881         call->event.funcs = &synth_event_funcs;
 882         call->class->fields_array = synth_event_fields_array;
 883
 884         ret = register_trace_event(&call->event);
 885         if (!ret) {
 886                 ret = -ENODEV;
 887                 goto out;
 888         }
 889         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 890         call->class->reg = trace_event_reg;
 891         call->class->probe = trace_event_raw_event_synth;
 892         call->data = event;
 893         call->tp = event->tp;
 894
 895         ret = trace_add_event_call(call);
 896         if (ret) {
 897                 pr_warn("Failed to register synthetic event: %s\n",
 898                         trace_event_name(call));
 899                 goto err;
 900         }
 901
 902         ret = set_synth_event_print_fmt(call);
 903         /* unregister_trace_event() will be called inside */
 904         if (ret < 0)
 905                 trace_remove_event_call(call);
 906  out:
 907         return ret;
 908  err:
 909         unregister_trace_event(&call->event);
 910         goto out;
 911 }
 912
 913 static int unregister_synth_event(struct synth_event *event)
 914 {
 915         struct trace_event_call *call = &event->call;
 916         int ret;
 917
 918         ret = trace_remove_event_call(call);
 919
 920         return ret;
 921 }
 922
 923 static void free_synth_event(struct synth_event *event)
 924 {
 925         unsigned int i;
 926
 927         if (!event)
 928                 return;
 929
 930         for (i = 0; i < event->n_fields; i++)
 931                 free_synth_field(event->fields[i]);
 932
 933         kfree(event->fields);
 934         kfree(event->dynamic_fields);
 935         kfree(event->name);
 936         kfree(event->class.system);
 937         free_synth_tracepoint(event->tp);
 938         free_synth_event_print_fmt(&event->call);
 939         kfree(event);
 940 }
 941
 942 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 943                                              struct synth_field **fields)
 944 {
 945         unsigned int i, j, n_dynamic_fields = 0;
 946         struct synth_event *event;
 947
 948         event = kzalloc(sizeof(*event), GFP_KERNEL);
 949         if (!event) {
 950                 event = ERR_PTR(-ENOMEM);
 951                 goto out;
 952         }
 953
 954         event->name = kstrdup(name, GFP_KERNEL);
 955         if (!event->name) {
 956                 kfree(event);
 957                 event = ERR_PTR(-ENOMEM);
 958                 goto out;
 959         }
 960
 961         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 962         if (!event->fields) {
 963                 free_synth_event(event);
 964                 event = ERR_PTR(-ENOMEM);
 965                 goto out;
 966         }
 967
 968         for (i = 0; i < n_fields; i++)
 969                 if (fields[i]->is_dynamic)
 970                         n_dynamic_fields++;
 971
 972         if (n_dynamic_fields) {
 973                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 974                                                 sizeof(*event->dynamic_fields),
 975                                                 GFP_KERNEL);
 976                 if (!event->dynamic_fields) {
 977                         free_synth_event(event);
 978                         event = ERR_PTR(-ENOMEM);
 979                         goto out;
 980                 }
 981         }
 982
 983         dyn_event_init(&event->devent, &synth_event_ops);
 984
 985         for (i = 0, j = 0; i < n_fields; i++) {
 986                 fields[i]->field_pos = i;
 987                 event->fields[i] = fields[i];
 988
 989                 if (fields[i]->is_dynamic)
 990                         event->dynamic_fields[j++] = fields[i];
 991         }
 992         event->n_dynamic_fields = j;
 993         event->n_fields = n_fields;
 994  out:
 995         return event;
 996 }
 997
 998 static int synth_event_check_arg_fn(void *data)
 999 {
1000         struct dynevent_arg_pair *arg_pair = data;
1001         int size;
1002
1003         size = synth_field_size((char *)arg_pair->lhs);
1004         if (size == 0) {
1005                 if (strstr((char *)arg_pair->lhs, "["))
1006                         return 0;
1007         }
1008
1009         return size ? 0 : -EINVAL;
1010 }
1011
1012 /**
1013  * synth_event_add_field - Add a new field to a synthetic event cmd
1014  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1015  * @type: The type of the new field to add
1016  * @name: The name of the new field to add
1017  *
1018  * Add a new field to a synthetic event cmd object.  Field ordering is in
1019  * the same order the fields are added.
1020  *
1021  * See synth_field_size() for available types. If field_name contains
1022  * [n] the field is considered to be an array.
1023  *
1024  * Return: 0 if successful, error otherwise.
1025  */
1026 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
1027                           const char *name)
1028 {
1029         struct dynevent_arg_pair arg_pair;
1030         int ret;
1031
1032         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1033                 return -EINVAL;
1034
1035         if (!type || !name)
1036                 return -EINVAL;
1037
1038         dynevent_arg_pair_init(&arg_pair, 0, ';');
1039
1040         arg_pair.lhs = type;
1041         arg_pair.rhs = name;
1042
1043         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
1044         if (ret)
1045                 return ret;
1046
1047         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1048                 ret = -EINVAL;
1049
1050         return ret;
1051 }
1052 EXPORT_SYMBOL_GPL(synth_event_add_field);
1053
1054 /**
1055  * synth_event_add_field_str - Add a new field to a synthetic event cmd
1056  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1057  * @type_name: The type and name of the new field to add, as a single string
1058  *
1059  * Add a new field to a synthetic event cmd object, as a single
1060  * string.  The @type_name string is expected to be of the form 'type
1061  * name', which will be appended by ';'.  No sanity checking is done -
1062  * what's passed in is assumed to already be well-formed.  Field
1063  * ordering is in the same order the fields are added.
1064  *
1065  * See synth_field_size() for available types. If field_name contains
1066  * [n] the field is considered to be an array.
1067  *
1068  * Return: 0 if successful, error otherwise.
1069  */
1070 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
1071 {
1072         struct dynevent_arg arg;
1073         int ret;
1074
1075         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1076                 return -EINVAL;
1077
1078         if (!type_name)
1079                 return -EINVAL;
1080
1081         dynevent_arg_init(&arg, ';');
1082
1083         arg.str = type_name;
1084
1085         ret = dynevent_arg_add(cmd, &arg, NULL);
1086         if (ret)
1087                 return ret;
1088
1089         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1090                 ret = -EINVAL;
1091
1092         return ret;
1093 }
1094 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1095
1096 /**
1097  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1098  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1099  * @fields: An array of type/name field descriptions
1100  * @n_fields: The number of field descriptions contained in the fields array
1101  *
1102  * Add a new set of fields to a synthetic event cmd object.  The event
1103  * fields that will be defined for the event should be passed in as an
1104  * array of struct synth_field_desc, and the number of elements in the
1105  * array passed in as n_fields.  Field ordering will retain the
1106  * ordering given in the fields array.
1107  *
1108  * See synth_field_size() for available types. If field_name contains
1109  * [n] the field is considered to be an array.
1110  *
1111  * Return: 0 if successful, error otherwise.
1112  */
1113 int synth_event_add_fields(struct dynevent_cmd *cmd,
1114                            struct synth_field_desc *fields,
1115                            unsigned int n_fields)
1116 {
1117         unsigned int i;
1118         int ret = 0;
1119
1120         for (i = 0; i < n_fields; i++) {
1121                 if (fields[i].type == NULL || fields[i].name == NULL) {
1122                         ret = -EINVAL;
1123                         break;
1124                 }
1125
1126                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1127                 if (ret)
1128                         break;
1129         }
1130
1131         return ret;
1132 }
1133 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1134
1135 /**
1136  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1137  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1138  * @name: The name of the synthetic event
1139  * @mod: The module creating the event, NULL if not created from a module
1140  * @args: Variable number of arg (pairs), one pair for each field
1141  *
1142  * NOTE: Users normally won't want to call this function directly, but
1143  * rather use the synth_event_gen_cmd_start() wrapper, which
1144  * automatically adds a NULL to the end of the arg list.  If this
1145  * function is used directly, make sure the last arg in the variable
1146  * arg list is NULL.
1147  *
1148  * Generate a synthetic event command to be executed by
1149  * synth_event_gen_cmd_end().  This function can be used to generate
1150  * the complete command or only the first part of it; in the latter
1151  * case, synth_event_add_field(), synth_event_add_field_str(), or
1152  * synth_event_add_fields() can be used to add more fields following
1153  * this.
1154  *
1155  * There should be an even number variable args, each pair consisting
1156  * of a type followed by a field name.
1157  *
1158  * See synth_field_size() for available types. If field_name contains
1159  * [n] the field is considered to be an array.
1160  *
1161  * Return: 0 if successful, error otherwise.
1162  */
1163 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1164                                 struct module *mod, ...)
1165 {
1166         struct dynevent_arg arg;
1167         va_list args;
1168         int ret;
1169
1170         cmd->event_name = name;
1171         cmd->private_data = mod;
1172
1173         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1174                 return -EINVAL;
1175
1176         dynevent_arg_init(&arg, 0);
1177         arg.str = name;
1178         ret = dynevent_arg_add(cmd, &arg, NULL);
1179         if (ret)
1180                 return ret;
1181
1182         va_start(args, mod);
1183         for (;;) {
1184                 const char *type, *name;
1185
1186                 type = va_arg(args, const char *);
1187                 if (!type)
1188                         break;
1189                 name = va_arg(args, const char *);
1190                 if (!name)
1191                         break;
1192
1193                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1194                         ret = -EINVAL;
1195                         break;
1196                 }
1197
1198                 ret = synth_event_add_field(cmd, type, name);
1199                 if (ret)
1200                         break;
1201         }
1202         va_end(args);
1203
1204         return ret;
1205 }
1206 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1207
1208 /**
1209  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1210  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1211  * @name: The name of the synthetic event
1212  * @mod: The module creating the event, NULL if not created from a module
1213  * @fields: An array of type/name field descriptions
1214  * @n_fields: The number of field descriptions contained in the fields array
1215  *
1216  * Generate a synthetic event command to be executed by
1217  * synth_event_gen_cmd_end().  This function can be used to generate
1218  * the complete command or only the first part of it; in the latter
1219  * case, synth_event_add_field(), synth_event_add_field_str(), or
1220  * synth_event_add_fields() can be used to add more fields following
1221  * this.
1222  *
1223  * The event fields that will be defined for the event should be
1224  * passed in as an array of struct synth_field_desc, and the number of
1225  * elements in the array passed in as n_fields.  Field ordering will
1226  * retain the ordering given in the fields array.
1227  *
1228  * See synth_field_size() for available types. If field_name contains
1229  * [n] the field is considered to be an array.
1230  *
1231  * Return: 0 if successful, error otherwise.
1232  */
1233 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1234                                     struct module *mod,
1235                                     struct synth_field_desc *fields,
1236                                     unsigned int n_fields)
1237 {
1238         struct dynevent_arg arg;
1239         unsigned int i;
1240         int ret = 0;
1241
1242         cmd->event_name = name;
1243         cmd->private_data = mod;
1244
1245         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1246                 return -EINVAL;
1247
1248         if (n_fields > SYNTH_FIELDS_MAX)
1249                 return -EINVAL;
1250
1251         dynevent_arg_init(&arg, 0);
1252         arg.str = name;
1253         ret = dynevent_arg_add(cmd, &arg, NULL);
1254         if (ret)
1255                 return ret;
1256
1257         for (i = 0; i < n_fields; i++) {
1258                 if (fields[i].type == NULL || fields[i].name == NULL)
1259                         return -EINVAL;
1260
1261                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1262                 if (ret)
1263                         break;
1264         }
1265
1266         return ret;
1267 }
1268 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1269
1270 static int __create_synth_event(const char *name, const char *raw_fields)
1271 {
1272         char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1273         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1274         int consumed, cmd_version = 1, n_fields_this_loop;
1275         int i, argc, n_fields = 0, ret = 0;
1276         struct synth_event *event = NULL;
1277
1278         /*
1279          * Argument syntax:
1280          *  - Add synthetic event: <event_name> field[;field] ...
1281          *  - Remove synthetic event: !<event_name> field[;field] ...
1282          *      where 'field' = type field_name
1283          */
1284
1285         if (name[0] == '\0') {
1286                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1287                 return -EINVAL;
1288         }
1289
1290         if (!is_good_name(name)) {
1291                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1292                 return -EINVAL;
1293         }
1294
1295         mutex_lock(&event_mutex);
1296
1297         event = find_synth_event(name);
1298         if (event) {
1299                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1300                 ret = -EEXIST;
1301                 goto err;
1302         }
1303
1304         tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1305         if (!tmp_fields) {
1306                 ret = -ENOMEM;
1307                 goto err;
1308         }
1309
1310         while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1311                 argv = argv_split(GFP_KERNEL, field_str, &argc);
1312                 if (!argv) {
1313                         ret = -ENOMEM;
1314                         goto err;
1315                 }
1316
1317                 if (!argc) {
1318                         argv_free(argv);
1319                         continue;
1320                 }
1321
1322                 n_fields_this_loop = 0;
1323                 consumed = 0;
1324                 while (argc > consumed) {
1325                         int field_version;
1326
1327                         field = parse_synth_field(argc - consumed,
1328                                                   argv + consumed, &consumed,
1329                                                   &field_version);
1330                         if (IS_ERR(field)) {
1331                                 ret = PTR_ERR(field);
1332                                 goto err_free_arg;
1333                         }
1334
1335                         /*
1336                          * Track the highest version of any field we
1337                          * found in the command.
1338                          */
1339                         if (field_version > cmd_version)
1340                                 cmd_version = field_version;
1341
1342                         /*
1343                          * Now sort out what is and isn't valid for
1344                          * each supported version.
1345                          *
1346                          * If we see more than 1 field per loop, it
1347                          * means we have multiple fields between
1348                          * semicolons, and that's something we no
1349                          * longer support in a version 2 or greater
1350                          * command.
1351                          */
1352                         if (cmd_version > 1 && n_fields_this_loop >= 1) {
1353                                 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1354                                 ret = -EINVAL;
1355                                 goto err_free_arg;
1356                         }
1357
1358                         if (n_fields == SYNTH_FIELDS_MAX) {
1359                                 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1360                                 ret = -EINVAL;
1361                                 goto err_free_arg;
1362                         }
1363                         fields[n_fields++] = field;
1364
1365                         n_fields_this_loop++;
1366                 }
1367                 argv_free(argv);
1368
1369                 if (consumed < argc) {
1370                         synth_err(SYNTH_ERR_INVALID_CMD, 0);
1371                         ret = -EINVAL;
1372                         goto err;
1373                 }
1374
1375         }
1376
1377         if (n_fields == 0) {
1378                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1379                 ret = -EINVAL;
1380                 goto err;
1381         }
1382
1383         event = alloc_synth_event(name, n_fields, fields);
1384         if (IS_ERR(event)) {
1385                 ret = PTR_ERR(event);
1386                 event = NULL;
1387                 goto err;
1388         }
1389         ret = register_synth_event(event);
1390         if (!ret)
1391                 dyn_event_add(&event->devent, &event->call);
1392         else
1393                 free_synth_event(event);
1394  out:
1395         mutex_unlock(&event_mutex);
1396
1397         kfree(saved_fields);
1398
1399         return ret;
1400  err_free_arg:
1401         argv_free(argv);
1402  err:
1403         for (i = 0; i < n_fields; i++)
1404                 free_synth_field(fields[i]);
1405
1406         goto out;
1407 }
1408
1409 /**
1410  * synth_event_create - Create a new synthetic event
1411  * @name: The name of the new synthetic event
1412  * @fields: An array of type/name field descriptions
1413  * @n_fields: The number of field descriptions contained in the fields array
1414  * @mod: The module creating the event, NULL if not created from a module
1415  *
1416  * Create a new synthetic event with the given name under the
1417  * trace/events/synthetic/ directory.  The event fields that will be
1418  * defined for the event should be passed in as an array of struct
1419  * synth_field_desc, and the number elements in the array passed in as
1420  * n_fields. Field ordering will retain the ordering given in the
1421  * fields array.
1422  *
1423  * If the new synthetic event is being created from a module, the mod
1424  * param must be non-NULL.  This will ensure that the trace buffer
1425  * won't contain unreadable events.
1426  *
1427  * The new synth event should be deleted using synth_event_delete()
1428  * function.  The new synthetic event can be generated from modules or
1429  * other kernel code using trace_synth_event() and related functions.
1430  *
1431  * Return: 0 if successful, error otherwise.
1432  */
1433 int synth_event_create(const char *name, struct synth_field_desc *fields,
1434                        unsigned int n_fields, struct module *mod)
1435 {
1436         struct dynevent_cmd cmd;
1437         char *buf;
1438         int ret;
1439
1440         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1441         if (!buf)
1442                 return -ENOMEM;
1443
1444         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1445
1446         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1447                                               fields, n_fields);
1448         if (ret)
1449                 goto out;
1450
1451         ret = synth_event_gen_cmd_end(&cmd);
1452  out:
1453         kfree(buf);
1454
1455         return ret;
1456 }
1457 EXPORT_SYMBOL_GPL(synth_event_create);
1458
1459 static int destroy_synth_event(struct synth_event *se)
1460 {
1461         int ret;
1462
1463         if (se->ref)
1464                 return -EBUSY;
1465
1466         if (trace_event_dyn_busy(&se->call))
1467                 return -EBUSY;
1468
1469         ret = unregister_synth_event(se);
1470         if (!ret) {
1471                 dyn_event_remove(&se->devent);
1472                 free_synth_event(se);
1473         }
1474
1475         return ret;
1476 }
1477
1478 /**
1479  * synth_event_delete - Delete a synthetic event
1480  * @event_name: The name of the new synthetic event
1481  *
1482  * Delete a synthetic event that was created with synth_event_create().
1483  *
1484  * Return: 0 if successful, error otherwise.
1485  */
1486 int synth_event_delete(const char *event_name)
1487 {
1488         struct synth_event *se = NULL;
1489         struct module *mod = NULL;
1490         int ret = -ENOENT;
1491
1492         mutex_lock(&event_mutex);
1493         se = find_synth_event(event_name);
1494         if (se) {
1495                 mod = se->mod;
1496                 ret = destroy_synth_event(se);
1497         }
1498         mutex_unlock(&event_mutex);
1499
1500         if (mod) {
1501                 /*
1502                  * It is safest to reset the ring buffer if the module
1503                  * being unloaded registered any events that were
1504                  * used. The only worry is if a new module gets
1505                  * loaded, and takes on the same id as the events of
1506                  * this module. When printing out the buffer, traced
1507                  * events left over from this module may be passed to
1508                  * the new module events and unexpected results may
1509                  * occur.
1510                  */
1511                 tracing_reset_all_online_cpus();
1512         }
1513
1514         return ret;
1515 }
1516 EXPORT_SYMBOL_GPL(synth_event_delete);
1517
1518 static int check_command(const char *raw_command)
1519 {
1520         char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1521         int argc, ret = 0;
1522
1523         cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1524         if (!cmd)
1525                 return -ENOMEM;
1526
1527         name_and_field = strsep(&cmd, ";");
1528         if (!name_and_field) {
1529                 ret = -EINVAL;
1530                 goto free;
1531         }
1532
1533         if (name_and_field[0] == '!')
1534                 goto free;
1535
1536         argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1537         if (!argv) {
1538                 ret = -ENOMEM;
1539                 goto free;
1540         }
1541         argv_free(argv);
1542
1543         if (argc < 3)
1544                 ret = -EINVAL;
1545 free:
1546         kfree(saved_cmd);
1547
1548         return ret;
1549 }
1550
1551 static int create_or_delete_synth_event(const char *raw_command)
1552 {
1553         char *name = NULL, *fields, *p;
1554         int ret = 0;
1555
1556         raw_command = skip_spaces(raw_command);
1557         if (raw_command[0] == '\0')
1558                 return ret;
1559
1560         last_cmd_set(raw_command);
1561
1562         ret = check_command(raw_command);
1563         if (ret) {
1564                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1565                 return ret;
1566         }
1567
1568         p = strpbrk(raw_command, " \t");
1569         if (!p && raw_command[0] != '!') {
1570                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1571                 ret = -EINVAL;
1572                 goto free;
1573         }
1574
1575         name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1576         if (!name)
1577                 return -ENOMEM;
1578
1579         if (name[0] == '!') {
1580                 ret = synth_event_delete(name + 1);
1581                 goto free;
1582         }
1583
1584         fields = skip_spaces(p);
1585
1586         ret = __create_synth_event(name, fields);
1587 free:
1588         kfree(name);
1589
1590         return ret;
1591 }
1592
1593 static int synth_event_run_command(struct dynevent_cmd *cmd)
1594 {
1595         struct synth_event *se;
1596         int ret;
1597
1598         ret = create_or_delete_synth_event(cmd->seq.buffer);
1599         if (ret)
1600                 return ret;
1601
1602         se = find_synth_event(cmd->event_name);
1603         if (WARN_ON(!se))
1604                 return -ENOENT;
1605
1606         se->mod = cmd->private_data;
1607
1608         return ret;
1609 }
1610
1611 /**
1612  * synth_event_cmd_init - Initialize a synthetic event command object
1613  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1614  * @buf: A pointer to the buffer used to build the command
1615  * @maxlen: The length of the buffer passed in @buf
1616  *
1617  * Initialize a synthetic event command object.  Use this before
1618  * calling any of the other dyenvent_cmd functions.
1619  */
1620 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1621 {
1622         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1623                           synth_event_run_command);
1624 }
1625 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1626
1627 static inline int
1628 __synth_event_trace_init(struct trace_event_file *file,
1629                          struct synth_event_trace_state *trace_state)
1630 {
1631         int ret = 0;
1632
1633         memset(trace_state, '\0', sizeof(*trace_state));
1634
1635         /*
1636          * Normal event tracing doesn't get called at all unless the
1637          * ENABLED bit is set (which attaches the probe thus allowing
1638          * this code to be called, etc).  Because this is called
1639          * directly by the user, we don't have that but we still need
1640          * to honor not logging when disabled.  For the iterated
1641          * trace case, we save the enabled state upon start and just
1642          * ignore the following data calls.
1643          */
1644         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1645             trace_trigger_soft_disabled(file)) {
1646                 trace_state->disabled = true;
1647                 ret = -ENOENT;
1648                 goto out;
1649         }
1650
1651         trace_state->event = file->event_call->data;
1652 out:
1653         return ret;
1654 }
1655
1656 static inline int
1657 __synth_event_trace_start(struct trace_event_file *file,
1658                           struct synth_event_trace_state *trace_state,
1659                           int dynamic_fields_size)
1660 {
1661         int entry_size, fields_size = 0;
1662         int ret = 0;
1663
1664         fields_size = trace_state->event->n_u64 * sizeof(u64);
1665         fields_size += dynamic_fields_size;
1666
1667         /*
1668          * Avoid ring buffer recursion detection, as this event
1669          * is being performed within another event.
1670          */
1671         trace_state->buffer = file->tr->array_buffer.buffer;
1672         ring_buffer_nest_start(trace_state->buffer);
1673
1674         entry_size = sizeof(*trace_state->entry) + fields_size;
1675         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1676                                                         file,
1677                                                         entry_size);
1678         if (!trace_state->entry) {
1679                 ring_buffer_nest_end(trace_state->buffer);
1680                 ret = -EINVAL;
1681         }
1682
1683         return ret;
1684 }
1685
1686 static inline void
1687 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1688 {
1689         trace_event_buffer_commit(&trace_state->fbuffer);
1690
1691         ring_buffer_nest_end(trace_state->buffer);
1692 }
1693
1694 /**
1695  * synth_event_trace - Trace a synthetic event
1696  * @file: The trace_event_file representing the synthetic event
1697  * @n_vals: The number of values in vals
1698  * @args: Variable number of args containing the event values
1699  *
1700  * Trace a synthetic event using the values passed in the variable
1701  * argument list.
1702  *
1703  * The argument list should be a list 'n_vals' u64 values.  The number
1704  * of vals must match the number of field in the synthetic event, and
1705  * must be in the same order as the synthetic event fields.
1706  *
1707  * All vals should be cast to u64, and string vals are just pointers
1708  * to strings, cast to u64.  Strings will be copied into space
1709  * reserved in the event for the string, using these pointers.
1710  *
1711  * Return: 0 on success, err otherwise.
1712  */
1713 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1714 {
1715         unsigned int i, n_u64, len, data_size = 0;
1716         struct synth_event_trace_state state;
1717         va_list args;
1718         int ret;
1719
1720         ret = __synth_event_trace_init(file, &state);
1721         if (ret) {
1722                 if (ret == -ENOENT)
1723                         ret = 0; /* just disabled, not really an error */
1724                 return ret;
1725         }
1726
1727         if (state.event->n_dynamic_fields) {
1728                 va_start(args, n_vals);
1729
1730                 for (i = 0; i < state.event->n_fields; i++) {
1731                         u64 val = va_arg(args, u64);
1732
1733                         if (state.event->fields[i]->is_string &&
1734                             state.event->fields[i]->is_dynamic) {
1735                                 char *str_val = (char *)(long)val;
1736
1737                                 data_size += strlen(str_val) + 1;
1738                         }
1739                 }
1740
1741                 va_end(args);
1742         }
1743
1744         ret = __synth_event_trace_start(file, &state, data_size);
1745         if (ret)
1746                 return ret;
1747
1748         if (n_vals != state.event->n_fields) {
1749                 ret = -EINVAL;
1750                 goto out;
1751         }
1752
1753         data_size = 0;
1754
1755         va_start(args, n_vals);
1756         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1757                 u64 val;
1758
1759                 val = va_arg(args, u64);
1760
1761                 if (state.event->fields[i]->is_string) {
1762                         char *str_val = (char *)(long)val;
1763
1764                         len = trace_string(state.entry, state.event, str_val,
1765                                            state.event->fields[i]->is_dynamic,
1766                                            data_size, &n_u64);
1767                         data_size += len; /* only dynamic string increments */
1768                 } else {
1769                         struct synth_field *field = state.event->fields[i];
1770
1771                         switch (field->size) {
1772                         case 1:
1773                                 state.entry->fields[n_u64].as_u8 = (u8)val;
1774                                 break;
1775
1776                         case 2:
1777                                 state.entry->fields[n_u64].as_u16 = (u16)val;
1778                                 break;
1779
1780                         case 4:
1781                                 state.entry->fields[n_u64].as_u32 = (u32)val;
1782                                 break;
1783
1784                         default:
1785                                 state.entry->fields[n_u64].as_u64 = val;
1786                                 break;
1787                         }
1788                         n_u64++;
1789                 }
1790         }
1791         va_end(args);
1792 out:
1793         __synth_event_trace_end(&state);
1794
1795         return ret;
1796 }
1797 EXPORT_SYMBOL_GPL(synth_event_trace);
1798
1799 /**
1800  * synth_event_trace_array - Trace a synthetic event from an array
1801  * @file: The trace_event_file representing the synthetic event
1802  * @vals: Array of values
1803  * @n_vals: The number of values in vals
1804  *
1805  * Trace a synthetic event using the values passed in as 'vals'.
1806  *
1807  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1808  * vals must match the number of field in the synthetic event, and
1809  * must be in the same order as the synthetic event fields.
1810  *
1811  * All vals should be cast to u64, and string vals are just pointers
1812  * to strings, cast to u64.  Strings will be copied into space
1813  * reserved in the event for the string, using these pointers.
1814  *
1815  * Return: 0 on success, err otherwise.
1816  */
1817 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1818                             unsigned int n_vals)
1819 {
1820         unsigned int i, n_u64, field_pos, len, data_size = 0;
1821         struct synth_event_trace_state state;
1822         char *str_val;
1823         int ret;
1824
1825         ret = __synth_event_trace_init(file, &state);
1826         if (ret) {
1827                 if (ret == -ENOENT)
1828                         ret = 0; /* just disabled, not really an error */
1829                 return ret;
1830         }
1831
1832         if (state.event->n_dynamic_fields) {
1833                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1834                         field_pos = state.event->dynamic_fields[i]->field_pos;
1835                         str_val = (char *)(long)vals[field_pos];
1836                         len = strlen(str_val) + 1;
1837                         data_size += len;
1838                 }
1839         }
1840
1841         ret = __synth_event_trace_start(file, &state, data_size);
1842         if (ret)
1843                 return ret;
1844
1845         if (n_vals != state.event->n_fields) {
1846                 ret = -EINVAL;
1847                 goto out;
1848         }
1849
1850         data_size = 0;
1851
1852         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1853                 if (state.event->fields[i]->is_string) {
1854                         char *str_val = (char *)(long)vals[i];
1855
1856                         len = trace_string(state.entry, state.event, str_val,
1857                                            state.event->fields[i]->is_dynamic,
1858                                            data_size, &n_u64);
1859                         data_size += len; /* only dynamic string increments */
1860                 } else {
1861                         struct synth_field *field = state.event->fields[i];
1862                         u64 val = vals[i];
1863
1864                         switch (field->size) {
1865                         case 1:
1866                                 state.entry->fields[n_u64].as_u8 = (u8)val;
1867                                 break;
1868
1869                         case 2:
1870                                 state.entry->fields[n_u64].as_u16 = (u16)val;
1871                                 break;
1872
1873                         case 4:
1874                                 state.entry->fields[n_u64].as_u32 = (u32)val;
1875                                 break;
1876
1877                         default:
1878                                 state.entry->fields[n_u64].as_u64 = val;
1879                                 break;
1880                         }
1881                         n_u64++;
1882                 }
1883         }
1884 out:
1885         __synth_event_trace_end(&state);
1886
1887         return ret;
1888 }
1889 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1890
1891 /**
1892  * synth_event_trace_start - Start piecewise synthetic event trace
1893  * @file: The trace_event_file representing the synthetic event
1894  * @trace_state: A pointer to object tracking the piecewise trace state
1895  *
1896  * Start the trace of a synthetic event field-by-field rather than all
1897  * at once.
1898  *
1899  * This function 'opens' an event trace, which means space is reserved
1900  * for the event in the trace buffer, after which the event's
1901  * individual field values can be set through either
1902  * synth_event_add_next_val() or synth_event_add_val().
1903  *
1904  * A pointer to a trace_state object is passed in, which will keep
1905  * track of the current event trace state until the event trace is
1906  * closed (and the event finally traced) using
1907  * synth_event_trace_end().
1908  *
1909  * Note that synth_event_trace_end() must be called after all values
1910  * have been added for each event trace, regardless of whether adding
1911  * all field values succeeded or not.
1912  *
1913  * Note also that for a given event trace, all fields must be added
1914  * using either synth_event_add_next_val() or synth_event_add_val()
1915  * but not both together or interleaved.
1916  *
1917  * Return: 0 on success, err otherwise.
1918  */
1919 int synth_event_trace_start(struct trace_event_file *file,
1920                             struct synth_event_trace_state *trace_state)
1921 {
1922         int ret;
1923
1924         if (!trace_state)
1925                 return -EINVAL;
1926
1927         ret = __synth_event_trace_init(file, trace_state);
1928         if (ret) {
1929                 if (ret == -ENOENT)
1930                         ret = 0; /* just disabled, not really an error */
1931                 return ret;
1932         }
1933
1934         if (trace_state->event->n_dynamic_fields)
1935                 return -ENOTSUPP;
1936
1937         ret = __synth_event_trace_start(file, trace_state, 0);
1938
1939         return ret;
1940 }
1941 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1942
1943 static int __synth_event_add_val(const char *field_name, u64 val,
1944                                  struct synth_event_trace_state *trace_state)
1945 {
1946         struct synth_field *field = NULL;
1947         struct synth_trace_event *entry;
1948         struct synth_event *event;
1949         int i, ret = 0;
1950
1951         if (!trace_state) {
1952                 ret = -EINVAL;
1953                 goto out;
1954         }
1955
1956         /* can't mix add_next_synth_val() with add_synth_val() */
1957         if (field_name) {
1958                 if (trace_state->add_next) {
1959                         ret = -EINVAL;
1960                         goto out;
1961                 }
1962                 trace_state->add_name = true;
1963         } else {
1964                 if (trace_state->add_name) {
1965                         ret = -EINVAL;
1966                         goto out;
1967                 }
1968                 trace_state->add_next = true;
1969         }
1970
1971         if (trace_state->disabled)
1972                 goto out;
1973
1974         event = trace_state->event;
1975         if (trace_state->add_name) {
1976                 for (i = 0; i < event->n_fields; i++) {
1977                         field = event->fields[i];
1978                         if (strcmp(field->name, field_name) == 0)
1979                                 break;
1980                 }
1981                 if (!field) {
1982                         ret = -EINVAL;
1983                         goto out;
1984                 }
1985         } else {
1986                 if (trace_state->cur_field >= event->n_fields) {
1987                         ret = -EINVAL;
1988                         goto out;
1989                 }
1990                 field = event->fields[trace_state->cur_field++];
1991         }
1992
1993         entry = trace_state->entry;
1994         if (field->is_string) {
1995                 char *str_val = (char *)(long)val;
1996                 char *str_field;
1997
1998                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
1999                         ret = -EINVAL;
2000                         goto out;
2001                 }
2002
2003                 if (!str_val) {
2004                         ret = -EINVAL;
2005                         goto out;
2006                 }
2007
2008                 str_field = (char *)&entry->fields[field->offset];
2009                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
2010         } else {
2011                 switch (field->size) {
2012                 case 1:
2013                         trace_state->entry->fields[field->offset].as_u8 = (u8)val;
2014                         break;
2015
2016                 case 2:
2017                         trace_state->entry->fields[field->offset].as_u16 = (u16)val;
2018                         break;
2019
2020                 case 4:
2021                         trace_state->entry->fields[field->offset].as_u32 = (u32)val;
2022                         break;
2023
2024                 default:
2025                         trace_state->entry->fields[field->offset].as_u64 = val;
2026                         break;
2027                 }
2028         }
2029  out:
2030         return ret;
2031 }
2032
2033 /**
2034  * synth_event_add_next_val - Add the next field's value to an open synth trace
2035  * @val: The value to set the next field to
2036  * @trace_state: A pointer to object tracking the piecewise trace state
2037  *
2038  * Set the value of the next field in an event that's been opened by
2039  * synth_event_trace_start().
2040  *
2041  * The val param should be the value cast to u64.  If the value points
2042  * to a string, the val param should be a char * cast to u64.
2043  *
2044  * This function assumes all the fields in an event are to be set one
2045  * after another - successive calls to this function are made, one for
2046  * each field, in the order of the fields in the event, until all
2047  * fields have been set.  If you'd rather set each field individually
2048  * without regard to ordering, synth_event_add_val() can be used
2049  * instead.
2050  *
2051  * Note however that synth_event_add_next_val() and
2052  * synth_event_add_val() can't be intermixed for a given event trace -
2053  * one or the other but not both can be used at the same time.
2054  *
2055  * Note also that synth_event_trace_end() must be called after all
2056  * values have been added for each event trace, regardless of whether
2057  * adding all field values succeeded or not.
2058  *
2059  * Return: 0 on success, err otherwise.
2060  */
2061 int synth_event_add_next_val(u64 val,
2062                              struct synth_event_trace_state *trace_state)
2063 {
2064         return __synth_event_add_val(NULL, val, trace_state);
2065 }
2066 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
2067
2068 /**
2069  * synth_event_add_val - Add a named field's value to an open synth trace
2070  * @field_name: The name of the synthetic event field value to set
2071  * @val: The value to set the named field to
2072  * @trace_state: A pointer to object tracking the piecewise trace state
2073  *
2074  * Set the value of the named field in an event that's been opened by
2075  * synth_event_trace_start().
2076  *
2077  * The val param should be the value cast to u64.  If the value points
2078  * to a string, the val param should be a char * cast to u64.
2079  *
2080  * This function looks up the field name, and if found, sets the field
2081  * to the specified value.  This lookup makes this function more
2082  * expensive than synth_event_add_next_val(), so use that or the
2083  * none-piecewise synth_event_trace() instead if efficiency is more
2084  * important.
2085  *
2086  * Note however that synth_event_add_next_val() and
2087  * synth_event_add_val() can't be intermixed for a given event trace -
2088  * one or the other but not both can be used at the same time.
2089  *
2090  * Note also that synth_event_trace_end() must be called after all
2091  * values have been added for each event trace, regardless of whether
2092  * adding all field values succeeded or not.
2093  *
2094  * Return: 0 on success, err otherwise.
2095  */
2096 int synth_event_add_val(const char *field_name, u64 val,
2097                         struct synth_event_trace_state *trace_state)
2098 {
2099         return __synth_event_add_val(field_name, val, trace_state);
2100 }
2101 EXPORT_SYMBOL_GPL(synth_event_add_val);
2102
2103 /**
2104  * synth_event_trace_end - End piecewise synthetic event trace
2105  * @trace_state: A pointer to object tracking the piecewise trace state
2106  *
2107  * End the trace of a synthetic event opened by
2108  * synth_event_trace__start().
2109  *
2110  * This function 'closes' an event trace, which basically means that
2111  * it commits the reserved event and cleans up other loose ends.
2112  *
2113  * A pointer to a trace_state object is passed in, which will keep
2114  * track of the current event trace state opened with
2115  * synth_event_trace_start().
2116  *
2117  * Note that this function must be called after all values have been
2118  * added for each event trace, regardless of whether adding all field
2119  * values succeeded or not.
2120  *
2121  * Return: 0 on success, err otherwise.
2122  */
2123 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2124 {
2125         if (!trace_state)
2126                 return -EINVAL;
2127
2128         __synth_event_trace_end(trace_state);
2129
2130         return 0;
2131 }
2132 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2133
2134 static int create_synth_event(const char *raw_command)
2135 {
2136         char *fields, *p;
2137         const char *name;
2138         int len, ret = 0;
2139
2140         raw_command = skip_spaces(raw_command);
2141         if (raw_command[0] == '\0')
2142                 return ret;
2143
2144         last_cmd_set(raw_command);
2145
2146         name = raw_command;
2147
2148         /* Don't try to process if not our system */
2149         if (name[0] != 's' || name[1] != ':')
2150                 return -ECANCELED;
2151         name += 2;
2152
2153         p = strpbrk(raw_command, " \t");
2154         if (!p) {
2155                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2156                 return -EINVAL;
2157         }
2158
2159         fields = skip_spaces(p);
2160
2161         /* This interface accepts group name prefix */
2162         if (strchr(name, '/')) {
2163                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2164                 if (len == 0) {
2165                         synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2166                         return -EINVAL;
2167                 }
2168                 name += len;
2169         }
2170
2171         len = name - raw_command;
2172
2173         ret = check_command(raw_command + len);
2174         if (ret) {
2175                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2176                 return ret;
2177         }
2178
2179         name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2180         if (!name)
2181                 return -ENOMEM;
2182
2183         ret = __create_synth_event(name, fields);
2184
2185         kfree(name);
2186
2187         return ret;
2188 }
2189
2190 static int synth_event_release(struct dyn_event *ev)
2191 {
2192         struct synth_event *event = to_synth_event(ev);
2193         int ret;
2194
2195         if (event->ref)
2196                 return -EBUSY;
2197
2198         if (trace_event_dyn_busy(&event->call))
2199                 return -EBUSY;
2200
2201         ret = unregister_synth_event(event);
2202         if (ret)
2203                 return ret;
2204
2205         dyn_event_remove(ev);
2206         free_synth_event(event);
2207         return 0;
2208 }
2209
2210 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2211 {
2212         struct synth_field *field;
2213         unsigned int i;
2214         char *type, *t;
2215
2216         seq_printf(m, "%s\t", event->name);
2217
2218         for (i = 0; i < event->n_fields; i++) {
2219                 field = event->fields[i];
2220
2221                 type = field->type;
2222                 t = strstr(type, "__data_loc");
2223                 if (t) { /* __data_loc belongs in format but not event desc */
2224                         t += sizeof("__data_loc");
2225                         type = t;
2226                 }
2227
2228                 /* parameter values */
2229                 seq_printf(m, "%s %s%s", type, field->name,
2230                            i == event->n_fields - 1 ? "" : "; ");
2231         }
2232
2233         seq_putc(m, '\n');
2234
2235         return 0;
2236 }
2237
2238 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2239 {
2240         struct synth_event *event = to_synth_event(ev);
2241
2242         seq_printf(m, "s:%s/", event->class.system);
2243
2244         return __synth_event_show(m, event);
2245 }
2246
2247 static int synth_events_seq_show(struct seq_file *m, void *v)
2248 {
2249         struct dyn_event *ev = v;
2250
2251         if (!is_synth_event(ev))
2252                 return 0;
2253
2254         return __synth_event_show(m, to_synth_event(ev));
2255 }
2256
2257 static const struct seq_operations synth_events_seq_op = {
2258         .start  = dyn_event_seq_start,
2259         .next   = dyn_event_seq_next,
2260         .stop   = dyn_event_seq_stop,
2261         .show   = synth_events_seq_show,
2262 };
2263
2264 static int synth_events_open(struct inode *inode, struct file *file)
2265 {
2266         int ret;
2267
2268         ret = security_locked_down(LOCKDOWN_TRACEFS);
2269         if (ret)
2270                 return ret;
2271
2272         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2273                 ret = dyn_events_release_all(&synth_event_ops);
2274                 if (ret < 0)
2275                         return ret;
2276         }
2277
2278         return seq_open(file, &synth_events_seq_op);
2279 }
2280
2281 static ssize_t synth_events_write(struct file *file,
2282                                   const char __user *buffer,
2283                                   size_t count, loff_t *ppos)
2284 {
2285         return trace_parse_run_command(file, buffer, count, ppos,
2286                                        create_or_delete_synth_event);
2287 }
2288
2289 static const struct file_operations synth_events_fops = {
2290         .open           = synth_events_open,
2291         .write          = synth_events_write,
2292         .read           = seq_read,
2293         .llseek         = seq_lseek,
2294         .release        = seq_release,
2295 };
2296
2297 /*
2298  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2299  * events in postcore_initcall without tracefs.
2300  */
2301 static __init int trace_events_synth_init_early(void)
2302 {
2303         int err = 0;
2304
2305         err = dyn_event_register(&synth_event_ops);
2306         if (err)
2307                 pr_warn("Could not register synth_event_ops\n");
2308
2309         return err;
2310 }
2311 core_initcall(trace_events_synth_init_early);
2312
2313 static __init int trace_events_synth_init(void)
2314 {
2315         struct dentry *entry = NULL;
2316         int err = 0;
2317         err = tracing_init_dentry();
2318         if (err)
2319                 goto err;
2320
2321         entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
2322                                     NULL, NULL, &synth_events_fops);
2323         if (!entry) {
2324                 err = -ENODEV;
2325                 goto err;
2326         }
2327
2328         return err;
2329  err:
2330         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2331
2332         return err;
2333 }
2334
2335 fs_initcall(trace_events_synth_init);