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