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 = fetch_store_strlen((unsigned long)str_val);
 452
 453                 data_offset |= len << 16;
 454                 *(u32 *)&entry->fields[*n_u64] = data_offset;
 455
 456                 ret = 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                 if (event->dynamic_fields[i]->is_stack) {
 542                         len = *((unsigned long *)str_val);
 543                         len *= sizeof(unsigned long);
 544                 } else {
 545                         len = fetch_store_strlen((unsigned long)str_val);
 546                 }
 547
 548                 fields_size += len;
 549         }
 550
 551         /*
 552          * Avoid ring buffer recursion detection, as this event
 553          * is being performed within another event.
 554          */
 555         buffer = trace_file->tr->array_buffer.buffer;
 556         ring_buffer_nest_start(buffer);
 557
 558         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 559                                            sizeof(*entry) + fields_size);
 560         if (!entry)
 561                 goto out;
 562
 563         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 564                 val_idx = var_ref_idx[i];
 565                 if (event->fields[i]->is_string) {
 566                         char *str_val = (char *)(long)var_ref_vals[val_idx];
 567
 568                         len = trace_string(entry, event, str_val,
 569                                            event->fields[i]->is_dynamic,
 570                                            data_size, &n_u64);
 571                         data_size += len; /* only dynamic string increments */
 572                 } else if (event->fields[i]->is_stack) {
 573                         long *stack = (long *)(long)var_ref_vals[val_idx];
 574
 575                         len = trace_stack(entry, event, stack,
 576                                            data_size, &n_u64);
 577                         data_size += len;
 578                 } else {
 579                         struct synth_field *field = event->fields[i];
 580                         u64 val = var_ref_vals[val_idx];
 581
 582                         switch (field->size) {
 583                         case 1:
 584                                 *(u8 *)&entry->fields[n_u64] = (u8)val;
 585                                 break;
 586
 587                         case 2:
 588                                 *(u16 *)&entry->fields[n_u64] = (u16)val;
 589                                 break;
 590
 591                         case 4:
 592                                 *(u32 *)&entry->fields[n_u64] = (u32)val;
 593                                 break;
 594
 595                         default:
 596                                 entry->fields[n_u64] = val;
 597                                 break;
 598                         }
 599                         n_u64++;
 600                 }
 601         }
 602
 603         trace_event_buffer_commit(&fbuffer);
 604 out:
 605         ring_buffer_nest_end(buffer);
 606 }
 607
 608 static void free_synth_event_print_fmt(struct trace_event_call *call)
 609 {
 610         if (call) {
 611                 kfree(call->print_fmt);
 612                 call->print_fmt = NULL;
 613         }
 614 }
 615
 616 static int __set_synth_event_print_fmt(struct synth_event *event,
 617                                        char *buf, int len)
 618 {
 619         const char *fmt;
 620         int pos = 0;
 621         int i;
 622
 623         /* When len=0, we just calculate the needed length */
 624 #define LEN_OR_ZERO (len ? len - pos : 0)
 625
 626         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 627         for (i = 0; i < event->n_fields; i++) {
 628                 fmt = synth_field_fmt(event->fields[i]->type);
 629                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 630                                 event->fields[i]->name, fmt,
 631                                 i == event->n_fields - 1 ? "" : ", ");
 632         }
 633         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 634
 635         for (i = 0; i < event->n_fields; i++) {
 636                 if (event->fields[i]->is_string &&
 637                     event->fields[i]->is_dynamic)
 638                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 639                                 ", __get_str(%s)", event->fields[i]->name);
 640                 else if (event->fields[i]->is_stack)
 641                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 642                                 ", __get_stacktrace(%s)", event->fields[i]->name);
 643                 else
 644                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 645                                         ", REC->%s", event->fields[i]->name);
 646         }
 647
 648 #undef LEN_OR_ZERO
 649
 650         /* return the length of print_fmt */
 651         return pos;
 652 }
 653
 654 static int set_synth_event_print_fmt(struct trace_event_call *call)
 655 {
 656         struct synth_event *event = call->data;
 657         char *print_fmt;
 658         int len;
 659
 660         /* First: called with 0 length to calculate the needed length */
 661         len = __set_synth_event_print_fmt(event, NULL, 0);
 662
 663         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 664         if (!print_fmt)
 665                 return -ENOMEM;
 666
 667         /* Second: actually write the @print_fmt */
 668         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 669         call->print_fmt = print_fmt;
 670
 671         return 0;
 672 }
 673
 674 static void free_synth_field(struct synth_field *field)
 675 {
 676         kfree(field->type);
 677         kfree(field->name);
 678         kfree(field);
 679 }
 680
 681 static int check_field_version(const char *prefix, const char *field_type,
 682                                const char *field_name)
 683 {
 684         /*
 685          * For backward compatibility, the old synthetic event command
 686          * format did not require semicolons, and in order to not
 687          * break user space, that old format must still work. If a new
 688          * feature is added, then the format that uses the new feature
 689          * will be required to have semicolons, as nothing that uses
 690          * the old format would be using the new, yet to be created,
 691          * feature. When a new feature is added, this will detect it,
 692          * and return a number greater than 1, and require the format
 693          * to use semicolons.
 694          */
 695         return 1;
 696 }
 697
 698 static struct synth_field *parse_synth_field(int argc, char **argv,
 699                                              int *consumed, int *field_version)
 700 {
 701         const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 702         struct synth_field *field;
 703         int len, ret = -ENOMEM;
 704         struct seq_buf s;
 705         ssize_t size;
 706
 707         if (!strcmp(field_type, "unsigned")) {
 708                 if (argc < 3) {
 709                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 710                         return ERR_PTR(-EINVAL);
 711                 }
 712                 prefix = "unsigned ";
 713                 field_type = argv[1];
 714                 field_name = argv[2];
 715                 *consumed += 3;
 716         } else {
 717                 field_name = argv[1];
 718                 *consumed += 2;
 719         }
 720
 721         if (!field_name) {
 722                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
 723                 return ERR_PTR(-EINVAL);
 724         }
 725
 726         *field_version = check_field_version(prefix, field_type, field_name);
 727
 728         field = kzalloc(sizeof(*field), GFP_KERNEL);
 729         if (!field)
 730                 return ERR_PTR(-ENOMEM);
 731
 732         len = strlen(field_name);
 733         array = strchr(field_name, '[');
 734         if (array)
 735                 len -= strlen(array);
 736
 737         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 738         if (!field->name)
 739                 goto free;
 740
 741         if (!is_good_name(field->name)) {
 742                 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 743                 ret = -EINVAL;
 744                 goto free;
 745         }
 746
 747         len = strlen(field_type) + 1;
 748
 749         if (array)
 750                 len += strlen(array);
 751
 752         if (prefix)
 753                 len += strlen(prefix);
 754
 755         field->type = kzalloc(len, GFP_KERNEL);
 756         if (!field->type)
 757                 goto free;
 758
 759         seq_buf_init(&s, field->type, len);
 760         if (prefix)
 761                 seq_buf_puts(&s, prefix);
 762         seq_buf_puts(&s, field_type);
 763         if (array)
 764                 seq_buf_puts(&s, array);
 765         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 766                 goto free;
 767
 768         s.buffer[s.len] = '\0';
 769
 770         size = synth_field_size(field->type);
 771         if (size < 0) {
 772                 if (array)
 773                         synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
 774                 else
 775                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 776                 ret = -EINVAL;
 777                 goto free;
 778         } else if (size == 0) {
 779                 if (synth_field_is_string(field->type) ||
 780                     synth_field_is_stack(field->type)) {
 781                         char *type;
 782
 783                         len = sizeof("__data_loc ") + strlen(field->type) + 1;
 784                         type = kzalloc(len, GFP_KERNEL);
 785                         if (!type)
 786                                 goto free;
 787
 788                         seq_buf_init(&s, type, len);
 789                         seq_buf_puts(&s, "__data_loc ");
 790                         seq_buf_puts(&s, field->type);
 791
 792                         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 793                                 goto free;
 794                         s.buffer[s.len] = '\0';
 795
 796                         kfree(field->type);
 797                         field->type = type;
 798
 799                         field->is_dynamic = true;
 800                         size = sizeof(u64);
 801                 } else {
 802                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 803                         ret = -EINVAL;
 804                         goto free;
 805                 }
 806         }
 807         field->size = size;
 808
 809         if (synth_field_is_string(field->type))
 810                 field->is_string = true;
 811         else if (synth_field_is_stack(field->type))
 812                 field->is_stack = true;
 813
 814         field->is_signed = synth_field_signed(field->type);
 815  out:
 816         return field;
 817  free:
 818         free_synth_field(field);
 819         field = ERR_PTR(ret);
 820         goto out;
 821 }
 822
 823 static void free_synth_tracepoint(struct tracepoint *tp)
 824 {
 825         if (!tp)
 826                 return;
 827
 828         kfree(tp->name);
 829         kfree(tp);
 830 }
 831
 832 static struct tracepoint *alloc_synth_tracepoint(char *name)
 833 {
 834         struct tracepoint *tp;
 835
 836         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 837         if (!tp)
 838                 return ERR_PTR(-ENOMEM);
 839
 840         tp->name = kstrdup(name, GFP_KERNEL);
 841         if (!tp->name) {
 842                 kfree(tp);
 843                 return ERR_PTR(-ENOMEM);
 844         }
 845
 846         return tp;
 847 }
 848
 849 struct synth_event *find_synth_event(const char *name)
 850 {
 851         struct dyn_event *pos;
 852         struct synth_event *event;
 853
 854         for_each_dyn_event(pos) {
 855                 if (!is_synth_event(pos))
 856                         continue;
 857                 event = to_synth_event(pos);
 858                 if (strcmp(event->name, name) == 0)
 859                         return event;
 860         }
 861
 862         return NULL;
 863 }
 864
 865 static struct trace_event_fields synth_event_fields_array[] = {
 866         { .type = TRACE_FUNCTION_TYPE,
 867           .define_fields = synth_event_define_fields },
 868         {}
 869 };
 870
 871 static int register_synth_event(struct synth_event *event)
 872 {
 873         struct trace_event_call *call = &event->call;
 874         int ret = 0;
 875
 876         event->call.class = &event->class;
 877         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 878         if (!event->class.system) {
 879                 ret = -ENOMEM;
 880                 goto out;
 881         }
 882
 883         event->tp = alloc_synth_tracepoint(event->name);
 884         if (IS_ERR(event->tp)) {
 885                 ret = PTR_ERR(event->tp);
 886                 event->tp = NULL;
 887                 goto out;
 888         }
 889
 890         INIT_LIST_HEAD(&call->class->fields);
 891         call->event.funcs = &synth_event_funcs;
 892         call->class->fields_array = synth_event_fields_array;
 893
 894         ret = register_trace_event(&call->event);
 895         if (!ret) {
 896                 ret = -ENODEV;
 897                 goto out;
 898         }
 899         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 900         call->class->reg = trace_event_reg;
 901         call->class->probe = trace_event_raw_event_synth;
 902         call->data = event;
 903         call->tp = event->tp;
 904
 905         ret = trace_add_event_call(call);
 906         if (ret) {
 907                 pr_warn("Failed to register synthetic event: %s\n",
 908                         trace_event_name(call));
 909                 goto err;
 910         }
 911
 912         ret = set_synth_event_print_fmt(call);
 913         /* unregister_trace_event() will be called inside */
 914         if (ret < 0)
 915                 trace_remove_event_call(call);
 916  out:
 917         return ret;
 918  err:
 919         unregister_trace_event(&call->event);
 920         goto out;
 921 }
 922
 923 static int unregister_synth_event(struct synth_event *event)
 924 {
 925         struct trace_event_call *call = &event->call;
 926         int ret;
 927
 928         ret = trace_remove_event_call(call);
 929
 930         return ret;
 931 }
 932
 933 static void free_synth_event(struct synth_event *event)
 934 {
 935         unsigned int i;
 936
 937         if (!event)
 938                 return;
 939
 940         for (i = 0; i < event->n_fields; i++)
 941                 free_synth_field(event->fields[i]);
 942
 943         kfree(event->fields);
 944         kfree(event->dynamic_fields);
 945         kfree(event->name);
 946         kfree(event->class.system);
 947         free_synth_tracepoint(event->tp);
 948         free_synth_event_print_fmt(&event->call);
 949         kfree(event);
 950 }
 951
 952 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 953                                              struct synth_field **fields)
 954 {
 955         unsigned int i, j, n_dynamic_fields = 0;
 956         struct synth_event *event;
 957
 958         event = kzalloc(sizeof(*event), GFP_KERNEL);
 959         if (!event) {
 960                 event = ERR_PTR(-ENOMEM);
 961                 goto out;
 962         }
 963
 964         event->name = kstrdup(name, GFP_KERNEL);
 965         if (!event->name) {
 966                 kfree(event);
 967                 event = ERR_PTR(-ENOMEM);
 968                 goto out;
 969         }
 970
 971         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 972         if (!event->fields) {
 973                 free_synth_event(event);
 974                 event = ERR_PTR(-ENOMEM);
 975                 goto out;
 976         }
 977
 978         for (i = 0; i < n_fields; i++)
 979                 if (fields[i]->is_dynamic)
 980                         n_dynamic_fields++;
 981
 982         if (n_dynamic_fields) {
 983                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 984                                                 sizeof(*event->dynamic_fields),
 985                                                 GFP_KERNEL);
 986                 if (!event->dynamic_fields) {
 987                         free_synth_event(event);
 988                         event = ERR_PTR(-ENOMEM);
 989                         goto out;
 990                 }
 991         }
 992
 993         dyn_event_init(&event->devent, &synth_event_ops);
 994
 995         for (i = 0, j = 0; i < n_fields; i++) {
 996                 fields[i]->field_pos = i;
 997                 event->fields[i] = fields[i];
 998
 999                 if (fields[i]->is_dynamic)
1000                         event->dynamic_fields[j++] = fields[i];
1001         }
1002         event->n_dynamic_fields = j;
1003         event->n_fields = n_fields;
1004  out:
1005         return event;
1006 }
1007
1008 static int synth_event_check_arg_fn(void *data)
1009 {
1010         struct dynevent_arg_pair *arg_pair = data;
1011         int size;
1012
1013         size = synth_field_size((char *)arg_pair->lhs);
1014         if (size == 0) {
1015                 if (strstr((char *)arg_pair->lhs, "["))
1016                         return 0;
1017         }
1018
1019         return size ? 0 : -EINVAL;
1020 }
1021
1022 /**
1023  * synth_event_add_field - Add a new field to a synthetic event cmd
1024  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1025  * @type: The type of the new field to add
1026  * @name: The name of the new field to add
1027  *
1028  * Add a new field to a synthetic event cmd object.  Field ordering is in
1029  * the same order the fields are added.
1030  *
1031  * See synth_field_size() for available types. If field_name contains
1032  * [n] the field is considered to be an array.
1033  *
1034  * Return: 0 if successful, error otherwise.
1035  */
1036 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
1037                           const char *name)
1038 {
1039         struct dynevent_arg_pair arg_pair;
1040         int ret;
1041
1042         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1043                 return -EINVAL;
1044
1045         if (!type || !name)
1046                 return -EINVAL;
1047
1048         dynevent_arg_pair_init(&arg_pair, 0, ';');
1049
1050         arg_pair.lhs = type;
1051         arg_pair.rhs = name;
1052
1053         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
1054         if (ret)
1055                 return ret;
1056
1057         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1058                 ret = -EINVAL;
1059
1060         return ret;
1061 }
1062 EXPORT_SYMBOL_GPL(synth_event_add_field);
1063
1064 /**
1065  * synth_event_add_field_str - Add a new field to a synthetic event cmd
1066  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1067  * @type_name: The type and name of the new field to add, as a single string
1068  *
1069  * Add a new field to a synthetic event cmd object, as a single
1070  * string.  The @type_name string is expected to be of the form 'type
1071  * name', which will be appended by ';'.  No sanity checking is done -
1072  * what's passed in is assumed to already be well-formed.  Field
1073  * ordering is in the same order the fields are added.
1074  *
1075  * See synth_field_size() for available types. If field_name contains
1076  * [n] the field is considered to be an array.
1077  *
1078  * Return: 0 if successful, error otherwise.
1079  */
1080 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
1081 {
1082         struct dynevent_arg arg;
1083         int ret;
1084
1085         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1086                 return -EINVAL;
1087
1088         if (!type_name)
1089                 return -EINVAL;
1090
1091         dynevent_arg_init(&arg, ';');
1092
1093         arg.str = type_name;
1094
1095         ret = dynevent_arg_add(cmd, &arg, NULL);
1096         if (ret)
1097                 return ret;
1098
1099         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1100                 ret = -EINVAL;
1101
1102         return ret;
1103 }
1104 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1105
1106 /**
1107  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1108  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1109  * @fields: An array of type/name field descriptions
1110  * @n_fields: The number of field descriptions contained in the fields array
1111  *
1112  * Add a new set of fields to a synthetic event cmd object.  The event
1113  * fields that will be defined for the event should be passed in as an
1114  * array of struct synth_field_desc, and the number of elements in the
1115  * array passed in as n_fields.  Field ordering will retain the
1116  * ordering given in the fields array.
1117  *
1118  * See synth_field_size() for available types. If field_name contains
1119  * [n] the field is considered to be an array.
1120  *
1121  * Return: 0 if successful, error otherwise.
1122  */
1123 int synth_event_add_fields(struct dynevent_cmd *cmd,
1124                            struct synth_field_desc *fields,
1125                            unsigned int n_fields)
1126 {
1127         unsigned int i;
1128         int ret = 0;
1129
1130         for (i = 0; i < n_fields; i++) {
1131                 if (fields[i].type == NULL || fields[i].name == NULL) {
1132                         ret = -EINVAL;
1133                         break;
1134                 }
1135
1136                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1137                 if (ret)
1138                         break;
1139         }
1140
1141         return ret;
1142 }
1143 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1144
1145 /**
1146  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1147  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1148  * @name: The name of the synthetic event
1149  * @mod: The module creating the event, NULL if not created from a module
1150  * @args: Variable number of arg (pairs), one pair for each field
1151  *
1152  * NOTE: Users normally won't want to call this function directly, but
1153  * rather use the synth_event_gen_cmd_start() wrapper, which
1154  * automatically adds a NULL to the end of the arg list.  If this
1155  * function is used directly, make sure the last arg in the variable
1156  * arg list is NULL.
1157  *
1158  * Generate a synthetic event command to be executed by
1159  * synth_event_gen_cmd_end().  This function can be used to generate
1160  * the complete command or only the first part of it; in the latter
1161  * case, synth_event_add_field(), synth_event_add_field_str(), or
1162  * synth_event_add_fields() can be used to add more fields following
1163  * this.
1164  *
1165  * There should be an even number variable args, each pair consisting
1166  * of a type followed by a field name.
1167  *
1168  * See synth_field_size() for available types. If field_name contains
1169  * [n] the field is considered to be an array.
1170  *
1171  * Return: 0 if successful, error otherwise.
1172  */
1173 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1174                                 struct module *mod, ...)
1175 {
1176         struct dynevent_arg arg;
1177         va_list args;
1178         int ret;
1179
1180         cmd->event_name = name;
1181         cmd->private_data = mod;
1182
1183         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1184                 return -EINVAL;
1185
1186         dynevent_arg_init(&arg, 0);
1187         arg.str = name;
1188         ret = dynevent_arg_add(cmd, &arg, NULL);
1189         if (ret)
1190                 return ret;
1191
1192         va_start(args, mod);
1193         for (;;) {
1194                 const char *type, *name;
1195
1196                 type = va_arg(args, const char *);
1197                 if (!type)
1198                         break;
1199                 name = va_arg(args, const char *);
1200                 if (!name)
1201                         break;
1202
1203                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1204                         ret = -EINVAL;
1205                         break;
1206                 }
1207
1208                 ret = synth_event_add_field(cmd, type, name);
1209                 if (ret)
1210                         break;
1211         }
1212         va_end(args);
1213
1214         return ret;
1215 }
1216 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1217
1218 /**
1219  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1220  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1221  * @name: The name of the synthetic event
1222  * @fields: An array of type/name field descriptions
1223  * @n_fields: The number of field descriptions contained in the fields array
1224  *
1225  * Generate a synthetic event command to be executed by
1226  * synth_event_gen_cmd_end().  This function can be used to generate
1227  * the complete command or only the first part of it; in the latter
1228  * case, synth_event_add_field(), synth_event_add_field_str(), or
1229  * synth_event_add_fields() can be used to add more fields following
1230  * this.
1231  *
1232  * The event fields that will be defined for the event should be
1233  * passed in as an array of struct synth_field_desc, and the number of
1234  * elements in the array passed in as n_fields.  Field ordering will
1235  * retain the ordering given in the fields array.
1236  *
1237  * See synth_field_size() for available types. If field_name contains
1238  * [n] the field is considered to be an array.
1239  *
1240  * Return: 0 if successful, error otherwise.
1241  */
1242 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1243                                     struct module *mod,
1244                                     struct synth_field_desc *fields,
1245                                     unsigned int n_fields)
1246 {
1247         struct dynevent_arg arg;
1248         unsigned int i;
1249         int ret = 0;
1250
1251         cmd->event_name = name;
1252         cmd->private_data = mod;
1253
1254         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1255                 return -EINVAL;
1256
1257         if (n_fields > SYNTH_FIELDS_MAX)
1258                 return -EINVAL;
1259
1260         dynevent_arg_init(&arg, 0);
1261         arg.str = name;
1262         ret = dynevent_arg_add(cmd, &arg, NULL);
1263         if (ret)
1264                 return ret;
1265
1266         for (i = 0; i < n_fields; i++) {
1267                 if (fields[i].type == NULL || fields[i].name == NULL)
1268                         return -EINVAL;
1269
1270                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1271                 if (ret)
1272                         break;
1273         }
1274
1275         return ret;
1276 }
1277 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1278
1279 static int __create_synth_event(const char *name, const char *raw_fields)
1280 {
1281         char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1282         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1283         int consumed, cmd_version = 1, n_fields_this_loop;
1284         int i, argc, n_fields = 0, ret = 0;
1285         struct synth_event *event = NULL;
1286
1287         /*
1288          * Argument syntax:
1289          *  - Add synthetic event: <event_name> field[;field] ...
1290          *  - Remove synthetic event: !<event_name> field[;field] ...
1291          *      where 'field' = type field_name
1292          */
1293
1294         if (name[0] == '\0') {
1295                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1296                 return -EINVAL;
1297         }
1298
1299         if (!is_good_name(name)) {
1300                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1301                 return -EINVAL;
1302         }
1303
1304         mutex_lock(&event_mutex);
1305
1306         event = find_synth_event(name);
1307         if (event) {
1308                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1309                 ret = -EEXIST;
1310                 goto err;
1311         }
1312
1313         tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1314         if (!tmp_fields) {
1315                 ret = -ENOMEM;
1316                 goto err;
1317         }
1318
1319         while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1320                 argv = argv_split(GFP_KERNEL, field_str, &argc);
1321                 if (!argv) {
1322                         ret = -ENOMEM;
1323                         goto err;
1324                 }
1325
1326                 if (!argc) {
1327                         argv_free(argv);
1328                         continue;
1329                 }
1330
1331                 n_fields_this_loop = 0;
1332                 consumed = 0;
1333                 while (argc > consumed) {
1334                         int field_version;
1335
1336                         field = parse_synth_field(argc - consumed,
1337                                                   argv + consumed, &consumed,
1338                                                   &field_version);
1339                         if (IS_ERR(field)) {
1340                                 ret = PTR_ERR(field);
1341                                 goto err_free_arg;
1342                         }
1343
1344                         /*
1345                          * Track the highest version of any field we
1346                          * found in the command.
1347                          */
1348                         if (field_version > cmd_version)
1349                                 cmd_version = field_version;
1350
1351                         /*
1352                          * Now sort out what is and isn't valid for
1353                          * each supported version.
1354                          *
1355                          * If we see more than 1 field per loop, it
1356                          * means we have multiple fields between
1357                          * semicolons, and that's something we no
1358                          * longer support in a version 2 or greater
1359                          * command.
1360                          */
1361                         if (cmd_version > 1 && n_fields_this_loop >= 1) {
1362                                 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1363                                 ret = -EINVAL;
1364                                 goto err_free_arg;
1365                         }
1366
1367                         if (n_fields == SYNTH_FIELDS_MAX) {
1368                                 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1369                                 ret = -EINVAL;
1370                                 goto err_free_arg;
1371                         }
1372                         fields[n_fields++] = field;
1373
1374                         n_fields_this_loop++;
1375                 }
1376                 argv_free(argv);
1377
1378                 if (consumed < argc) {
1379                         synth_err(SYNTH_ERR_INVALID_CMD, 0);
1380                         ret = -EINVAL;
1381                         goto err;
1382                 }
1383
1384         }
1385
1386         if (n_fields == 0) {
1387                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1388                 ret = -EINVAL;
1389                 goto err;
1390         }
1391
1392         event = alloc_synth_event(name, n_fields, fields);
1393         if (IS_ERR(event)) {
1394                 ret = PTR_ERR(event);
1395                 event = NULL;
1396                 goto err;
1397         }
1398         ret = register_synth_event(event);
1399         if (!ret)
1400                 dyn_event_add(&event->devent, &event->call);
1401         else
1402                 free_synth_event(event);
1403  out:
1404         mutex_unlock(&event_mutex);
1405
1406         kfree(saved_fields);
1407
1408         return ret;
1409  err_free_arg:
1410         argv_free(argv);
1411  err:
1412         for (i = 0; i < n_fields; i++)
1413                 free_synth_field(fields[i]);
1414
1415         goto out;
1416 }
1417
1418 /**
1419  * synth_event_create - Create a new synthetic event
1420  * @name: The name of the new synthetic event
1421  * @fields: An array of type/name field descriptions
1422  * @n_fields: The number of field descriptions contained in the fields array
1423  * @mod: The module creating the event, NULL if not created from a module
1424  *
1425  * Create a new synthetic event with the given name under the
1426  * trace/events/synthetic/ directory.  The event fields that will be
1427  * defined for the event should be passed in as an array of struct
1428  * synth_field_desc, and the number elements in the array passed in as
1429  * n_fields. Field ordering will retain the ordering given in the
1430  * fields array.
1431  *
1432  * If the new synthetic event is being created from a module, the mod
1433  * param must be non-NULL.  This will ensure that the trace buffer
1434  * won't contain unreadable events.
1435  *
1436  * The new synth event should be deleted using synth_event_delete()
1437  * function.  The new synthetic event can be generated from modules or
1438  * other kernel code using trace_synth_event() and related functions.
1439  *
1440  * Return: 0 if successful, error otherwise.
1441  */
1442 int synth_event_create(const char *name, struct synth_field_desc *fields,
1443                        unsigned int n_fields, struct module *mod)
1444 {
1445         struct dynevent_cmd cmd;
1446         char *buf;
1447         int ret;
1448
1449         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1450         if (!buf)
1451                 return -ENOMEM;
1452
1453         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1454
1455         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1456                                               fields, n_fields);
1457         if (ret)
1458                 goto out;
1459
1460         ret = synth_event_gen_cmd_end(&cmd);
1461  out:
1462         kfree(buf);
1463
1464         return ret;
1465 }
1466 EXPORT_SYMBOL_GPL(synth_event_create);
1467
1468 static int destroy_synth_event(struct synth_event *se)
1469 {
1470         int ret;
1471
1472         if (se->ref)
1473                 return -EBUSY;
1474
1475         if (trace_event_dyn_busy(&se->call))
1476                 return -EBUSY;
1477
1478         ret = unregister_synth_event(se);
1479         if (!ret) {
1480                 dyn_event_remove(&se->devent);
1481                 free_synth_event(se);
1482         }
1483
1484         return ret;
1485 }
1486
1487 /**
1488  * synth_event_delete - Delete a synthetic event
1489  * @event_name: The name of the new synthetic event
1490  *
1491  * Delete a synthetic event that was created with synth_event_create().
1492  *
1493  * Return: 0 if successful, error otherwise.
1494  */
1495 int synth_event_delete(const char *event_name)
1496 {
1497         struct synth_event *se = NULL;
1498         struct module *mod = NULL;
1499         int ret = -ENOENT;
1500
1501         mutex_lock(&event_mutex);
1502         se = find_synth_event(event_name);
1503         if (se) {
1504                 mod = se->mod;
1505                 ret = destroy_synth_event(se);
1506         }
1507         mutex_unlock(&event_mutex);
1508
1509         if (mod) {
1510                 /*
1511                  * It is safest to reset the ring buffer if the module
1512                  * being unloaded registered any events that were
1513                  * used. The only worry is if a new module gets
1514                  * loaded, and takes on the same id as the events of
1515                  * this module. When printing out the buffer, traced
1516                  * events left over from this module may be passed to
1517                  * the new module events and unexpected results may
1518                  * occur.
1519                  */
1520                 tracing_reset_all_online_cpus();
1521         }
1522
1523         return ret;
1524 }
1525 EXPORT_SYMBOL_GPL(synth_event_delete);
1526
1527 static int check_command(const char *raw_command)
1528 {
1529         char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1530         int argc, ret = 0;
1531
1532         cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1533         if (!cmd)
1534                 return -ENOMEM;
1535
1536         name_and_field = strsep(&cmd, ";");
1537         if (!name_and_field) {
1538                 ret = -EINVAL;
1539                 goto free;
1540         }
1541
1542         if (name_and_field[0] == '!')
1543                 goto free;
1544
1545         argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1546         if (!argv) {
1547                 ret = -ENOMEM;
1548                 goto free;
1549         }
1550         argv_free(argv);
1551
1552         if (argc < 3)
1553                 ret = -EINVAL;
1554 free:
1555         kfree(saved_cmd);
1556
1557         return ret;
1558 }
1559
1560 static int create_or_delete_synth_event(const char *raw_command)
1561 {
1562         char *name = NULL, *fields, *p;
1563         int ret = 0;
1564
1565         raw_command = skip_spaces(raw_command);
1566         if (raw_command[0] == '\0')
1567                 return ret;
1568
1569         last_cmd_set(raw_command);
1570
1571         ret = check_command(raw_command);
1572         if (ret) {
1573                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1574                 return ret;
1575         }
1576
1577         p = strpbrk(raw_command, " \t");
1578         if (!p && raw_command[0] != '!') {
1579                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1580                 ret = -EINVAL;
1581                 goto free;
1582         }
1583
1584         name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1585         if (!name)
1586                 return -ENOMEM;
1587
1588         if (name[0] == '!') {
1589                 ret = synth_event_delete(name + 1);
1590                 goto free;
1591         }
1592
1593         fields = skip_spaces(p);
1594
1595         ret = __create_synth_event(name, fields);
1596 free:
1597         kfree(name);
1598
1599         return ret;
1600 }
1601
1602 static int synth_event_run_command(struct dynevent_cmd *cmd)
1603 {
1604         struct synth_event *se;
1605         int ret;
1606
1607         ret = create_or_delete_synth_event(cmd->seq.buffer);
1608         if (ret)
1609                 return ret;
1610
1611         se = find_synth_event(cmd->event_name);
1612         if (WARN_ON(!se))
1613                 return -ENOENT;
1614
1615         se->mod = cmd->private_data;
1616
1617         return ret;
1618 }
1619
1620 /**
1621  * synth_event_cmd_init - Initialize a synthetic event command object
1622  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1623  * @buf: A pointer to the buffer used to build the command
1624  * @maxlen: The length of the buffer passed in @buf
1625  *
1626  * Initialize a synthetic event command object.  Use this before
1627  * calling any of the other dyenvent_cmd functions.
1628  */
1629 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1630 {
1631         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1632                           synth_event_run_command);
1633 }
1634 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1635
1636 static inline int
1637 __synth_event_trace_init(struct trace_event_file *file,
1638                          struct synth_event_trace_state *trace_state)
1639 {
1640         int ret = 0;
1641
1642         memset(trace_state, '\0', sizeof(*trace_state));
1643
1644         /*
1645          * Normal event tracing doesn't get called at all unless the
1646          * ENABLED bit is set (which attaches the probe thus allowing
1647          * this code to be called, etc).  Because this is called
1648          * directly by the user, we don't have that but we still need
1649          * to honor not logging when disabled.  For the iterated
1650          * trace case, we save the enabled state upon start and just
1651          * ignore the following data calls.
1652          */
1653         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1654             trace_trigger_soft_disabled(file)) {
1655                 trace_state->disabled = true;
1656                 ret = -ENOENT;
1657                 goto out;
1658         }
1659
1660         trace_state->event = file->event_call->data;
1661 out:
1662         return ret;
1663 }
1664
1665 static inline int
1666 __synth_event_trace_start(struct trace_event_file *file,
1667                           struct synth_event_trace_state *trace_state,
1668                           int dynamic_fields_size)
1669 {
1670         int entry_size, fields_size = 0;
1671         int ret = 0;
1672
1673         fields_size = trace_state->event->n_u64 * sizeof(u64);
1674         fields_size += dynamic_fields_size;
1675
1676         /*
1677          * Avoid ring buffer recursion detection, as this event
1678          * is being performed within another event.
1679          */
1680         trace_state->buffer = file->tr->array_buffer.buffer;
1681         ring_buffer_nest_start(trace_state->buffer);
1682
1683         entry_size = sizeof(*trace_state->entry) + fields_size;
1684         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1685                                                         file,
1686                                                         entry_size);
1687         if (!trace_state->entry) {
1688                 ring_buffer_nest_end(trace_state->buffer);
1689                 ret = -EINVAL;
1690         }
1691
1692         return ret;
1693 }
1694
1695 static inline void
1696 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1697 {
1698         trace_event_buffer_commit(&trace_state->fbuffer);
1699
1700         ring_buffer_nest_end(trace_state->buffer);
1701 }
1702
1703 /**
1704  * synth_event_trace - Trace a synthetic event
1705  * @file: The trace_event_file representing the synthetic event
1706  * @n_vals: The number of values in vals
1707  * @args: Variable number of args containing the event values
1708  *
1709  * Trace a synthetic event using the values passed in the variable
1710  * argument list.
1711  *
1712  * The argument list should be a list 'n_vals' u64 values.  The number
1713  * of vals must match the number of field in the synthetic event, and
1714  * must be in the same order as the synthetic event fields.
1715  *
1716  * All vals should be cast to u64, and string vals are just pointers
1717  * to strings, cast to u64.  Strings will be copied into space
1718  * reserved in the event for the string, using these pointers.
1719  *
1720  * Return: 0 on success, err otherwise.
1721  */
1722 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1723 {
1724         unsigned int i, n_u64, len, data_size = 0;
1725         struct synth_event_trace_state state;
1726         va_list args;
1727         int ret;
1728
1729         ret = __synth_event_trace_init(file, &state);
1730         if (ret) {
1731                 if (ret == -ENOENT)
1732                         ret = 0; /* just disabled, not really an error */
1733                 return ret;
1734         }
1735
1736         if (state.event->n_dynamic_fields) {
1737                 va_start(args, n_vals);
1738
1739                 for (i = 0; i < state.event->n_fields; i++) {
1740                         u64 val = va_arg(args, u64);
1741
1742                         if (state.event->fields[i]->is_string &&
1743                             state.event->fields[i]->is_dynamic) {
1744                                 char *str_val = (char *)(long)val;
1745
1746                                 data_size += strlen(str_val) + 1;
1747                         }
1748                 }
1749
1750                 va_end(args);
1751         }
1752
1753         ret = __synth_event_trace_start(file, &state, data_size);
1754         if (ret)
1755                 return ret;
1756
1757         if (n_vals != state.event->n_fields) {
1758                 ret = -EINVAL;
1759                 goto out;
1760         }
1761
1762         data_size = 0;
1763
1764         va_start(args, n_vals);
1765         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1766                 u64 val;
1767
1768                 val = va_arg(args, u64);
1769
1770                 if (state.event->fields[i]->is_string) {
1771                         char *str_val = (char *)(long)val;
1772
1773                         len = trace_string(state.entry, state.event, str_val,
1774                                            state.event->fields[i]->is_dynamic,
1775                                            data_size, &n_u64);
1776                         data_size += len; /* only dynamic string increments */
1777                 } else {
1778                         struct synth_field *field = state.event->fields[i];
1779
1780                         switch (field->size) {
1781                         case 1:
1782                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1783                                 break;
1784
1785                         case 2:
1786                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1787                                 break;
1788
1789                         case 4:
1790                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1791                                 break;
1792
1793                         default:
1794                                 state.entry->fields[n_u64] = val;
1795                                 break;
1796                         }
1797                         n_u64++;
1798                 }
1799         }
1800         va_end(args);
1801 out:
1802         __synth_event_trace_end(&state);
1803
1804         return ret;
1805 }
1806 EXPORT_SYMBOL_GPL(synth_event_trace);
1807
1808 /**
1809  * synth_event_trace_array - Trace a synthetic event from an array
1810  * @file: The trace_event_file representing the synthetic event
1811  * @vals: Array of values
1812  * @n_vals: The number of values in vals
1813  *
1814  * Trace a synthetic event using the values passed in as 'vals'.
1815  *
1816  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1817  * vals must match the number of field in the synthetic event, and
1818  * must be in the same order as the synthetic event fields.
1819  *
1820  * All vals should be cast to u64, and string vals are just pointers
1821  * to strings, cast to u64.  Strings will be copied into space
1822  * reserved in the event for the string, using these pointers.
1823  *
1824  * Return: 0 on success, err otherwise.
1825  */
1826 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1827                             unsigned int n_vals)
1828 {
1829         unsigned int i, n_u64, field_pos, len, data_size = 0;
1830         struct synth_event_trace_state state;
1831         char *str_val;
1832         int ret;
1833
1834         ret = __synth_event_trace_init(file, &state);
1835         if (ret) {
1836                 if (ret == -ENOENT)
1837                         ret = 0; /* just disabled, not really an error */
1838                 return ret;
1839         }
1840
1841         if (state.event->n_dynamic_fields) {
1842                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1843                         field_pos = state.event->dynamic_fields[i]->field_pos;
1844                         str_val = (char *)(long)vals[field_pos];
1845                         len = strlen(str_val) + 1;
1846                         data_size += len;
1847                 }
1848         }
1849
1850         ret = __synth_event_trace_start(file, &state, data_size);
1851         if (ret)
1852                 return ret;
1853
1854         if (n_vals != state.event->n_fields) {
1855                 ret = -EINVAL;
1856                 goto out;
1857         }
1858
1859         data_size = 0;
1860
1861         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1862                 if (state.event->fields[i]->is_string) {
1863                         char *str_val = (char *)(long)vals[i];
1864
1865                         len = trace_string(state.entry, state.event, str_val,
1866                                            state.event->fields[i]->is_dynamic,
1867                                            data_size, &n_u64);
1868                         data_size += len; /* only dynamic string increments */
1869                 } else {
1870                         struct synth_field *field = state.event->fields[i];
1871                         u64 val = vals[i];
1872
1873                         switch (field->size) {
1874                         case 1:
1875                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1876                                 break;
1877
1878                         case 2:
1879                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1880                                 break;
1881
1882                         case 4:
1883                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1884                                 break;
1885
1886                         default:
1887                                 state.entry->fields[n_u64] = val;
1888                                 break;
1889                         }
1890                         n_u64++;
1891                 }
1892         }
1893 out:
1894         __synth_event_trace_end(&state);
1895
1896         return ret;
1897 }
1898 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1899
1900 /**
1901  * synth_event_trace_start - Start piecewise synthetic event trace
1902  * @file: The trace_event_file representing the synthetic event
1903  * @trace_state: A pointer to object tracking the piecewise trace state
1904  *
1905  * Start the trace of a synthetic event field-by-field rather than all
1906  * at once.
1907  *
1908  * This function 'opens' an event trace, which means space is reserved
1909  * for the event in the trace buffer, after which the event's
1910  * individual field values can be set through either
1911  * synth_event_add_next_val() or synth_event_add_val().
1912  *
1913  * A pointer to a trace_state object is passed in, which will keep
1914  * track of the current event trace state until the event trace is
1915  * closed (and the event finally traced) using
1916  * synth_event_trace_end().
1917  *
1918  * Note that synth_event_trace_end() must be called after all values
1919  * have been added for each event trace, regardless of whether adding
1920  * all field values succeeded or not.
1921  *
1922  * Note also that for a given event trace, all fields must be added
1923  * using either synth_event_add_next_val() or synth_event_add_val()
1924  * but not both together or interleaved.
1925  *
1926  * Return: 0 on success, err otherwise.
1927  */
1928 int synth_event_trace_start(struct trace_event_file *file,
1929                             struct synth_event_trace_state *trace_state)
1930 {
1931         int ret;
1932
1933         if (!trace_state)
1934                 return -EINVAL;
1935
1936         ret = __synth_event_trace_init(file, trace_state);
1937         if (ret) {
1938                 if (ret == -ENOENT)
1939                         ret = 0; /* just disabled, not really an error */
1940                 return ret;
1941         }
1942
1943         if (trace_state->event->n_dynamic_fields)
1944                 return -ENOTSUPP;
1945
1946         ret = __synth_event_trace_start(file, trace_state, 0);
1947
1948         return ret;
1949 }
1950 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1951
1952 static int __synth_event_add_val(const char *field_name, u64 val,
1953                                  struct synth_event_trace_state *trace_state)
1954 {
1955         struct synth_field *field = NULL;
1956         struct synth_trace_event *entry;
1957         struct synth_event *event;
1958         int i, ret = 0;
1959
1960         if (!trace_state) {
1961                 ret = -EINVAL;
1962                 goto out;
1963         }
1964
1965         /* can't mix add_next_synth_val() with add_synth_val() */
1966         if (field_name) {
1967                 if (trace_state->add_next) {
1968                         ret = -EINVAL;
1969                         goto out;
1970                 }
1971                 trace_state->add_name = true;
1972         } else {
1973                 if (trace_state->add_name) {
1974                         ret = -EINVAL;
1975                         goto out;
1976                 }
1977                 trace_state->add_next = true;
1978         }
1979
1980         if (trace_state->disabled)
1981                 goto out;
1982
1983         event = trace_state->event;
1984         if (trace_state->add_name) {
1985                 for (i = 0; i < event->n_fields; i++) {
1986                         field = event->fields[i];
1987                         if (strcmp(field->name, field_name) == 0)
1988                                 break;
1989                 }
1990                 if (!field) {
1991                         ret = -EINVAL;
1992                         goto out;
1993                 }
1994         } else {
1995                 if (trace_state->cur_field >= event->n_fields) {
1996                         ret = -EINVAL;
1997                         goto out;
1998                 }
1999                 field = event->fields[trace_state->cur_field++];
2000         }
2001
2002         entry = trace_state->entry;
2003         if (field->is_string) {
2004                 char *str_val = (char *)(long)val;
2005                 char *str_field;
2006
2007                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
2008                         ret = -EINVAL;
2009                         goto out;
2010                 }
2011
2012                 if (!str_val) {
2013                         ret = -EINVAL;
2014                         goto out;
2015                 }
2016
2017                 str_field = (char *)&entry->fields[field->offset];
2018                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
2019         } else {
2020                 switch (field->size) {
2021                 case 1:
2022                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
2023                         break;
2024
2025                 case 2:
2026                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
2027                         break;
2028
2029                 case 4:
2030                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
2031                         break;
2032
2033                 default:
2034                         trace_state->entry->fields[field->offset] = val;
2035                         break;
2036                 }
2037         }
2038  out:
2039         return ret;
2040 }
2041
2042 /**
2043  * synth_event_add_next_val - Add the next field's value to an open synth trace
2044  * @val: The value to set the next field to
2045  * @trace_state: A pointer to object tracking the piecewise trace state
2046  *
2047  * Set the value of the next field in an event that's been opened by
2048  * synth_event_trace_start().
2049  *
2050  * The val param should be the value cast to u64.  If the value points
2051  * to a string, the val param should be a char * cast to u64.
2052  *
2053  * This function assumes all the fields in an event are to be set one
2054  * after another - successive calls to this function are made, one for
2055  * each field, in the order of the fields in the event, until all
2056  * fields have been set.  If you'd rather set each field individually
2057  * without regard to ordering, synth_event_add_val() can be used
2058  * instead.
2059  *
2060  * Note however that synth_event_add_next_val() and
2061  * synth_event_add_val() can't be intermixed for a given event trace -
2062  * one or the other but not both can be used at the same time.
2063  *
2064  * Note also that synth_event_trace_end() must be called after all
2065  * values have been added for each event trace, regardless of whether
2066  * adding all field values succeeded or not.
2067  *
2068  * Return: 0 on success, err otherwise.
2069  */
2070 int synth_event_add_next_val(u64 val,
2071                              struct synth_event_trace_state *trace_state)
2072 {
2073         return __synth_event_add_val(NULL, val, trace_state);
2074 }
2075 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
2076
2077 /**
2078  * synth_event_add_val - Add a named field's value to an open synth trace
2079  * @field_name: The name of the synthetic event field value to set
2080  * @val: The value to set the named field to
2081  * @trace_state: A pointer to object tracking the piecewise trace state
2082  *
2083  * Set the value of the named field in an event that's been opened by
2084  * synth_event_trace_start().
2085  *
2086  * The val param should be the value cast to u64.  If the value points
2087  * to a string, the val param should be a char * cast to u64.
2088  *
2089  * This function looks up the field name, and if found, sets the field
2090  * to the specified value.  This lookup makes this function more
2091  * expensive than synth_event_add_next_val(), so use that or the
2092  * none-piecewise synth_event_trace() instead if efficiency is more
2093  * important.
2094  *
2095  * Note however that synth_event_add_next_val() and
2096  * synth_event_add_val() can't be intermixed for a given event trace -
2097  * one or the other but not both can be used at the same time.
2098  *
2099  * Note also that synth_event_trace_end() must be called after all
2100  * values have been added for each event trace, regardless of whether
2101  * adding all field values succeeded or not.
2102  *
2103  * Return: 0 on success, err otherwise.
2104  */
2105 int synth_event_add_val(const char *field_name, u64 val,
2106                         struct synth_event_trace_state *trace_state)
2107 {
2108         return __synth_event_add_val(field_name, val, trace_state);
2109 }
2110 EXPORT_SYMBOL_GPL(synth_event_add_val);
2111
2112 /**
2113  * synth_event_trace_end - End piecewise synthetic event trace
2114  * @trace_state: A pointer to object tracking the piecewise trace state
2115  *
2116  * End the trace of a synthetic event opened by
2117  * synth_event_trace__start().
2118  *
2119  * This function 'closes' an event trace, which basically means that
2120  * it commits the reserved event and cleans up other loose ends.
2121  *
2122  * A pointer to a trace_state object is passed in, which will keep
2123  * track of the current event trace state opened with
2124  * synth_event_trace_start().
2125  *
2126  * Note that this function must be called after all values have been
2127  * added for each event trace, regardless of whether adding all field
2128  * values succeeded or not.
2129  *
2130  * Return: 0 on success, err otherwise.
2131  */
2132 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2133 {
2134         if (!trace_state)
2135                 return -EINVAL;
2136
2137         __synth_event_trace_end(trace_state);
2138
2139         return 0;
2140 }
2141 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2142
2143 static int create_synth_event(const char *raw_command)
2144 {
2145         char *fields, *p;
2146         const char *name;
2147         int len, ret = 0;
2148
2149         raw_command = skip_spaces(raw_command);
2150         if (raw_command[0] == '\0')
2151                 return ret;
2152
2153         last_cmd_set(raw_command);
2154
2155         name = raw_command;
2156
2157         /* Don't try to process if not our system */
2158         if (name[0] != 's' || name[1] != ':')
2159                 return -ECANCELED;
2160         name += 2;
2161
2162         p = strpbrk(raw_command, " \t");
2163         if (!p) {
2164                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2165                 return -EINVAL;
2166         }
2167
2168         fields = skip_spaces(p);
2169
2170         /* This interface accepts group name prefix */
2171         if (strchr(name, '/')) {
2172                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2173                 if (len == 0) {
2174                         synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2175                         return -EINVAL;
2176                 }
2177                 name += len;
2178         }
2179
2180         len = name - raw_command;
2181
2182         ret = check_command(raw_command + len);
2183         if (ret) {
2184                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2185                 return ret;
2186         }
2187
2188         name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2189         if (!name)
2190                 return -ENOMEM;
2191
2192         ret = __create_synth_event(name, fields);
2193
2194         kfree(name);
2195
2196         return ret;
2197 }
2198
2199 static int synth_event_release(struct dyn_event *ev)
2200 {
2201         struct synth_event *event = to_synth_event(ev);
2202         int ret;
2203
2204         if (event->ref)
2205                 return -EBUSY;
2206
2207         if (trace_event_dyn_busy(&event->call))
2208                 return -EBUSY;
2209
2210         ret = unregister_synth_event(event);
2211         if (ret)
2212                 return ret;
2213
2214         dyn_event_remove(ev);
2215         free_synth_event(event);
2216         return 0;
2217 }
2218
2219 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2220 {
2221         struct synth_field *field;
2222         unsigned int i;
2223         char *type, *t;
2224
2225         seq_printf(m, "%s\t", event->name);
2226
2227         for (i = 0; i < event->n_fields; i++) {
2228                 field = event->fields[i];
2229
2230                 type = field->type;
2231                 t = strstr(type, "__data_loc");
2232                 if (t) { /* __data_loc belongs in format but not event desc */
2233                         t += sizeof("__data_loc");
2234                         type = t;
2235                 }
2236
2237                 /* parameter values */
2238                 seq_printf(m, "%s %s%s", type, field->name,
2239                            i == event->n_fields - 1 ? "" : "; ");
2240         }
2241
2242         seq_putc(m, '\n');
2243
2244         return 0;
2245 }
2246
2247 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2248 {
2249         struct synth_event *event = to_synth_event(ev);
2250
2251         seq_printf(m, "s:%s/", event->class.system);
2252
2253         return __synth_event_show(m, event);
2254 }
2255
2256 static int synth_events_seq_show(struct seq_file *m, void *v)
2257 {
2258         struct dyn_event *ev = v;
2259
2260         if (!is_synth_event(ev))
2261                 return 0;
2262
2263         return __synth_event_show(m, to_synth_event(ev));
2264 }
2265
2266 static const struct seq_operations synth_events_seq_op = {
2267         .start  = dyn_event_seq_start,
2268         .next   = dyn_event_seq_next,
2269         .stop   = dyn_event_seq_stop,
2270         .show   = synth_events_seq_show,
2271 };
2272
2273 static int synth_events_open(struct inode *inode, struct file *file)
2274 {
2275         int ret;
2276
2277         ret = security_locked_down(LOCKDOWN_TRACEFS);
2278         if (ret)
2279                 return ret;
2280
2281         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2282                 ret = dyn_events_release_all(&synth_event_ops);
2283                 if (ret < 0)
2284                         return ret;
2285         }
2286
2287         return seq_open(file, &synth_events_seq_op);
2288 }
2289
2290 static ssize_t synth_events_write(struct file *file,
2291                                   const char __user *buffer,
2292                                   size_t count, loff_t *ppos)
2293 {
2294         return trace_parse_run_command(file, buffer, count, ppos,
2295                                        create_or_delete_synth_event);
2296 }
2297
2298 static const struct file_operations synth_events_fops = {
2299         .open           = synth_events_open,
2300         .write          = synth_events_write,
2301         .read           = seq_read,
2302         .llseek         = seq_lseek,
2303         .release        = seq_release,
2304 };
2305
2306 /*
2307  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2308  * events in postcore_initcall without tracefs.
2309  */
2310 static __init int trace_events_synth_init_early(void)
2311 {
2312         int err = 0;
2313
2314         err = dyn_event_register(&synth_event_ops);
2315         if (err)
2316                 pr_warn("Could not register synth_event_ops\n");
2317
2318         return err;
2319 }
2320 core_initcall(trace_events_synth_init_early);
2321
2322 static __init int trace_events_synth_init(void)
2323 {
2324         struct dentry *entry = NULL;
2325         int err = 0;
2326         err = tracing_init_dentry();
2327         if (err)
2328                 goto err;
2329
2330         entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
2331                                     NULL, NULL, &synth_events_fops);
2332         if (!entry) {
2333                 err = -ENODEV;
2334                 goto err;
2335         }
2336
2337         return err;
2338  err:
2339         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2340
2341         return err;
2342 }
2343
2344 fs_initcall(trace_events_synth_init);