kernel/trace/trace_events_hist.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_hist - trace event hist triggers
   4  *
   5  * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kallsyms.h>
  10 #include <linux/mutex.h>
  11 #include <linux/slab.h>
  12 #include <linux/stacktrace.h>
  13 #include <linux/rculist.h>
  14 #include <linux/tracefs.h>
  15
  16 #include "tracing_map.h"
  17 #include "trace.h"
  18
  19 #define SYNTH_SYSTEM            "synthetic"
  20 #define SYNTH_FIELDS_MAX        16
  21
  22 #define STR_VAR_LEN_MAX         32 /* must be multiple of sizeof(u64) */
  23
  24 struct hist_field;
  25
  26 typedef u64 (*hist_field_fn_t) (struct hist_field *field,
  27                                 struct tracing_map_elt *elt,
  28                                 struct ring_buffer_event *rbe,
  29                                 void *event);
  30
  31 #define HIST_FIELD_OPERANDS_MAX 2
  32 #define HIST_FIELDS_MAX         (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
  33 #define HIST_ACTIONS_MAX        8
  34
  35 enum field_op_id {
  36         FIELD_OP_NONE,
  37         FIELD_OP_PLUS,
  38         FIELD_OP_MINUS,
  39         FIELD_OP_UNARY_MINUS,
  40 };
  41
  42 struct hist_var {
  43         char                            *name;
  44         struct hist_trigger_data        *hist_data;
  45         unsigned int                    idx;
  46 };
  47
  48 struct hist_field {
  49         struct ftrace_event_field       *field;
  50         unsigned long                   flags;
  51         hist_field_fn_t                 fn;
  52         unsigned int                    size;
  53         unsigned int                    offset;
  54         unsigned int                    is_signed;
  55         const char                      *type;
  56         struct hist_field               *operands[HIST_FIELD_OPERANDS_MAX];
  57         struct hist_trigger_data        *hist_data;
  58         struct hist_var                 var;
  59         enum field_op_id                operator;
  60         char                            *system;
  61         char                            *event_name;
  62         char                            *name;
  63         unsigned int                    var_idx;
  64         unsigned int                    var_ref_idx;
  65         bool                            read_once;
  66 };
  67
  68 static u64 hist_field_none(struct hist_field *field,
  69                            struct tracing_map_elt *elt,
  70                            struct ring_buffer_event *rbe,
  71                            void *event)
  72 {
  73         return 0;
  74 }
  75
  76 static u64 hist_field_counter(struct hist_field *field,
  77                               struct tracing_map_elt *elt,
  78                               struct ring_buffer_event *rbe,
  79                               void *event)
  80 {
  81         return 1;
  82 }
  83
  84 static u64 hist_field_string(struct hist_field *hist_field,
  85                              struct tracing_map_elt *elt,
  86                              struct ring_buffer_event *rbe,
  87                              void *event)
  88 {
  89         char *addr = (char *)(event + hist_field->field->offset);
  90
  91         return (u64)(unsigned long)addr;
  92 }
  93
  94 static u64 hist_field_dynstring(struct hist_field *hist_field,
  95                                 struct tracing_map_elt *elt,
  96                                 struct ring_buffer_event *rbe,
  97                                 void *event)
  98 {
  99         u32 str_item = *(u32 *)(event + hist_field->field->offset);
 100         int str_loc = str_item & 0xffff;
 101         char *addr = (char *)(event + str_loc);
 102
 103         return (u64)(unsigned long)addr;
 104 }
 105
 106 static u64 hist_field_pstring(struct hist_field *hist_field,
 107                               struct tracing_map_elt *elt,
 108                               struct ring_buffer_event *rbe,
 109                               void *event)
 110 {
 111         char **addr = (char **)(event + hist_field->field->offset);
 112
 113         return (u64)(unsigned long)*addr;
 114 }
 115
 116 static u64 hist_field_log2(struct hist_field *hist_field,
 117                            struct tracing_map_elt *elt,
 118                            struct ring_buffer_event *rbe,
 119                            void *event)
 120 {
 121         struct hist_field *operand = hist_field->operands[0];
 122
 123         u64 val = operand->fn(operand, elt, rbe, event);
 124
 125         return (u64) ilog2(roundup_pow_of_two(val));
 126 }
 127
 128 static u64 hist_field_plus(struct hist_field *hist_field,
 129                            struct tracing_map_elt *elt,
 130                            struct ring_buffer_event *rbe,
 131                            void *event)
 132 {
 133         struct hist_field *operand1 = hist_field->operands[0];
 134         struct hist_field *operand2 = hist_field->operands[1];
 135
 136         u64 val1 = operand1->fn(operand1, elt, rbe, event);
 137         u64 val2 = operand2->fn(operand2, elt, rbe, event);
 138
 139         return val1 + val2;
 140 }
 141
 142 static u64 hist_field_minus(struct hist_field *hist_field,
 143                             struct tracing_map_elt *elt,
 144                             struct ring_buffer_event *rbe,
 145                             void *event)
 146 {
 147         struct hist_field *operand1 = hist_field->operands[0];
 148         struct hist_field *operand2 = hist_field->operands[1];
 149
 150         u64 val1 = operand1->fn(operand1, elt, rbe, event);
 151         u64 val2 = operand2->fn(operand2, elt, rbe, event);
 152
 153         return val1 - val2;
 154 }
 155
 156 static u64 hist_field_unary_minus(struct hist_field *hist_field,
 157                                   struct tracing_map_elt *elt,
 158                                   struct ring_buffer_event *rbe,
 159                                   void *event)
 160 {
 161         struct hist_field *operand = hist_field->operands[0];
 162
 163         s64 sval = (s64)operand->fn(operand, elt, rbe, event);
 164         u64 val = (u64)-sval;
 165
 166         return val;
 167 }
 168
 169 #define DEFINE_HIST_FIELD_FN(type)                                      \
 170         static u64 hist_field_##type(struct hist_field *hist_field,     \
 171                                      struct tracing_map_elt *elt,       \
 172                                      struct ring_buffer_event *rbe,     \
 173                                      void *event)                       \
 174 {                                                                       \
 175         type *addr = (type *)(event + hist_field->field->offset);       \
 176                                                                         \
 177         return (u64)(unsigned long)*addr;                               \
 178 }
 179
 180 DEFINE_HIST_FIELD_FN(s64);
 181 DEFINE_HIST_FIELD_FN(u64);
 182 DEFINE_HIST_FIELD_FN(s32);
 183 DEFINE_HIST_FIELD_FN(u32);
 184 DEFINE_HIST_FIELD_FN(s16);
 185 DEFINE_HIST_FIELD_FN(u16);
 186 DEFINE_HIST_FIELD_FN(s8);
 187 DEFINE_HIST_FIELD_FN(u8);
 188
 189 #define for_each_hist_field(i, hist_data)       \
 190         for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
 191
 192 #define for_each_hist_val_field(i, hist_data)   \
 193         for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
 194
 195 #define for_each_hist_key_field(i, hist_data)   \
 196         for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
 197
 198 #define HIST_STACKTRACE_DEPTH   16
 199 #define HIST_STACKTRACE_SIZE    (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
 200 #define HIST_STACKTRACE_SKIP    5
 201
 202 #define HITCOUNT_IDX            0
 203 #define HIST_KEY_SIZE_MAX       (MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
 204
 205 enum hist_field_flags {
 206         HIST_FIELD_FL_HITCOUNT          = 1 << 0,
 207         HIST_FIELD_FL_KEY               = 1 << 1,
 208         HIST_FIELD_FL_STRING            = 1 << 2,
 209         HIST_FIELD_FL_HEX               = 1 << 3,
 210         HIST_FIELD_FL_SYM               = 1 << 4,
 211         HIST_FIELD_FL_SYM_OFFSET        = 1 << 5,
 212         HIST_FIELD_FL_EXECNAME          = 1 << 6,
 213         HIST_FIELD_FL_SYSCALL           = 1 << 7,
 214         HIST_FIELD_FL_STACKTRACE        = 1 << 8,
 215         HIST_FIELD_FL_LOG2              = 1 << 9,
 216         HIST_FIELD_FL_TIMESTAMP         = 1 << 10,
 217         HIST_FIELD_FL_TIMESTAMP_USECS   = 1 << 11,
 218         HIST_FIELD_FL_VAR               = 1 << 12,
 219         HIST_FIELD_FL_EXPR              = 1 << 13,
 220         HIST_FIELD_FL_VAR_REF           = 1 << 14,
 221         HIST_FIELD_FL_CPU               = 1 << 15,
 222         HIST_FIELD_FL_ALIAS             = 1 << 16,
 223 };
 224
 225 struct var_defs {
 226         unsigned int    n_vars;
 227         char            *name[TRACING_MAP_VARS_MAX];
 228         char            *expr[TRACING_MAP_VARS_MAX];
 229 };
 230
 231 struct hist_trigger_attrs {
 232         char            *keys_str;
 233         char            *vals_str;
 234         char            *sort_key_str;
 235         char            *name;
 236         char            *clock;
 237         bool            pause;
 238         bool            cont;
 239         bool            clear;
 240         bool            ts_in_usecs;
 241         unsigned int    map_bits;
 242
 243         char            *assignment_str[TRACING_MAP_VARS_MAX];
 244         unsigned int    n_assignments;
 245
 246         char            *action_str[HIST_ACTIONS_MAX];
 247         unsigned int    n_actions;
 248
 249         struct var_defs var_defs;
 250 };
 251
 252 struct field_var {
 253         struct hist_field       *var;
 254         struct hist_field       *val;
 255 };
 256
 257 struct field_var_hist {
 258         struct hist_trigger_data        *hist_data;
 259         char                            *cmd;
 260 };
 261
 262 struct hist_trigger_data {
 263         struct hist_field               *fields[HIST_FIELDS_MAX];
 264         unsigned int                    n_vals;
 265         unsigned int                    n_keys;
 266         unsigned int                    n_fields;
 267         unsigned int                    n_vars;
 268         unsigned int                    key_size;
 269         struct tracing_map_sort_key     sort_keys[TRACING_MAP_SORT_KEYS_MAX];
 270         unsigned int                    n_sort_keys;
 271         struct trace_event_file         *event_file;
 272         struct hist_trigger_attrs       *attrs;
 273         struct tracing_map              *map;
 274         bool                            enable_timestamps;
 275         bool                            remove;
 276         struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
 277         unsigned int                    n_var_refs;
 278
 279         struct action_data              *actions[HIST_ACTIONS_MAX];
 280         unsigned int                    n_actions;
 281
 282         struct hist_field               *synth_var_refs[SYNTH_FIELDS_MAX];
 283         unsigned int                    n_synth_var_refs;
 284         struct field_var                *field_vars[SYNTH_FIELDS_MAX];
 285         unsigned int                    n_field_vars;
 286         unsigned int                    n_field_var_str;
 287         struct field_var_hist           *field_var_hists[SYNTH_FIELDS_MAX];
 288         unsigned int                    n_field_var_hists;
 289
 290         struct field_var                *max_vars[SYNTH_FIELDS_MAX];
 291         unsigned int                    n_max_vars;
 292         unsigned int                    n_max_var_str;
 293 };
 294
 295 struct synth_field {
 296         char *type;
 297         char *name;
 298         size_t size;
 299         bool is_signed;
 300         bool is_string;
 301 };
 302
 303 struct synth_event {
 304         struct list_head                        list;
 305         int                                     ref;
 306         char                                    *name;
 307         struct synth_field                      **fields;
 308         unsigned int                            n_fields;
 309         unsigned int                            n_u64;
 310         struct trace_event_class                class;
 311         struct trace_event_call                 call;
 312         struct tracepoint                       *tp;
 313 };
 314
 315 struct action_data;
 316
 317 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
 318                              struct tracing_map_elt *elt, void *rec,
 319                              struct ring_buffer_event *rbe,
 320                              struct action_data *data, u64 *var_ref_vals);
 321
 322 struct action_data {
 323         action_fn_t             fn;
 324         unsigned int            n_params;
 325         char                    *params[SYNTH_FIELDS_MAX];
 326
 327         union {
 328                 struct {
 329                         unsigned int            var_ref_idx;
 330                         char                    *match_event;
 331                         char                    *match_event_system;
 332                         char                    *synth_event_name;
 333                         struct synth_event      *synth_event;
 334                 } onmatch;
 335
 336                 struct {
 337                         char                    *var_str;
 338                         char                    *fn_name;
 339                         unsigned int            max_var_ref_idx;
 340                         struct hist_field       *max_var;
 341                         struct hist_field       *var;
 342                 } onmax;
 343         };
 344 };
 345
 346
 347 static char last_hist_cmd[MAX_FILTER_STR_VAL];
 348 static char hist_err_str[MAX_FILTER_STR_VAL];
 349
 350 static void last_cmd_set(char *str)
 351 {
 352         if (!str)
 353                 return;
 354
 355         strncpy(last_hist_cmd, str, MAX_FILTER_STR_VAL - 1);
 356 }
 357
 358 static void hist_err(char *str, char *var)
 359 {
 360         int maxlen = MAX_FILTER_STR_VAL - 1;
 361
 362         if (!str)
 363                 return;
 364
 365         if (strlen(hist_err_str))
 366                 return;
 367
 368         if (!var)
 369                 var = "";
 370
 371         if (strlen(hist_err_str) + strlen(str) + strlen(var) > maxlen)
 372                 return;
 373
 374         strcat(hist_err_str, str);
 375         strcat(hist_err_str, var);
 376 }
 377
 378 static void hist_err_event(char *str, char *system, char *event, char *var)
 379 {
 380         char err[MAX_FILTER_STR_VAL];
 381
 382         if (system && var)
 383                 snprintf(err, MAX_FILTER_STR_VAL, "%s.%s.%s", system, event, var);
 384         else if (system)
 385                 snprintf(err, MAX_FILTER_STR_VAL, "%s.%s", system, event);
 386         else
 387                 strscpy(err, var, MAX_FILTER_STR_VAL);
 388
 389         hist_err(str, err);
 390 }
 391
 392 static void hist_err_clear(void)
 393 {
 394         hist_err_str[0] = '\0';
 395 }
 396
 397 static bool have_hist_err(void)
 398 {
 399         if (strlen(hist_err_str))
 400                 return true;
 401
 402         return false;
 403 }
 404
 405 static LIST_HEAD(synth_event_list);
 406 static DEFINE_MUTEX(synth_event_mutex);
 407
 408 struct synth_trace_event {
 409         struct trace_entry      ent;
 410         u64                     fields[];
 411 };
 412
 413 static int synth_event_define_fields(struct trace_event_call *call)
 414 {
 415         struct synth_trace_event trace;
 416         int offset = offsetof(typeof(trace), fields);
 417         struct synth_event *event = call->data;
 418         unsigned int i, size, n_u64;
 419         char *name, *type;
 420         bool is_signed;
 421         int ret = 0;
 422
 423         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 424                 size = event->fields[i]->size;
 425                 is_signed = event->fields[i]->is_signed;
 426                 type = event->fields[i]->type;
 427                 name = event->fields[i]->name;
 428                 ret = trace_define_field(call, type, name, offset, size,
 429                                          is_signed, FILTER_OTHER);
 430                 if (ret)
 431                         break;
 432
 433                 if (event->fields[i]->is_string) {
 434                         offset += STR_VAR_LEN_MAX;
 435                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 436                 } else {
 437                         offset += sizeof(u64);
 438                         n_u64++;
 439                 }
 440         }
 441
 442         event->n_u64 = n_u64;
 443
 444         return ret;
 445 }
 446
 447 static bool synth_field_signed(char *type)
 448 {
 449         if (strncmp(type, "u", 1) == 0)
 450                 return false;
 451
 452         return true;
 453 }
 454
 455 static int synth_field_is_string(char *type)
 456 {
 457         if (strstr(type, "char[") != NULL)
 458                 return true;
 459
 460         return false;
 461 }
 462
 463 static int synth_field_string_size(char *type)
 464 {
 465         char buf[4], *end, *start;
 466         unsigned int len;
 467         int size, err;
 468
 469         start = strstr(type, "char[");
 470         if (start == NULL)
 471                 return -EINVAL;
 472         start += strlen("char[");
 473
 474         end = strchr(type, ']');
 475         if (!end || end < start)
 476                 return -EINVAL;
 477
 478         len = end - start;
 479         if (len > 3)
 480                 return -EINVAL;
 481
 482         strncpy(buf, start, len);
 483         buf[len] = '\0';
 484
 485         err = kstrtouint(buf, 0, &size);
 486         if (err)
 487                 return err;
 488
 489         if (size > STR_VAR_LEN_MAX)
 490                 return -EINVAL;
 491
 492         return size;
 493 }
 494
 495 static int synth_field_size(char *type)
 496 {
 497         int size = 0;
 498
 499         if (strcmp(type, "s64") == 0)
 500                 size = sizeof(s64);
 501         else if (strcmp(type, "u64") == 0)
 502                 size = sizeof(u64);
 503         else if (strcmp(type, "s32") == 0)
 504                 size = sizeof(s32);
 505         else if (strcmp(type, "u32") == 0)
 506                 size = sizeof(u32);
 507         else if (strcmp(type, "s16") == 0)
 508                 size = sizeof(s16);
 509         else if (strcmp(type, "u16") == 0)
 510                 size = sizeof(u16);
 511         else if (strcmp(type, "s8") == 0)
 512                 size = sizeof(s8);
 513         else if (strcmp(type, "u8") == 0)
 514                 size = sizeof(u8);
 515         else if (strcmp(type, "char") == 0)
 516                 size = sizeof(char);
 517         else if (strcmp(type, "unsigned char") == 0)
 518                 size = sizeof(unsigned char);
 519         else if (strcmp(type, "int") == 0)
 520                 size = sizeof(int);
 521         else if (strcmp(type, "unsigned int") == 0)
 522                 size = sizeof(unsigned int);
 523         else if (strcmp(type, "long") == 0)
 524                 size = sizeof(long);
 525         else if (strcmp(type, "unsigned long") == 0)
 526                 size = sizeof(unsigned long);
 527         else if (strcmp(type, "pid_t") == 0)
 528                 size = sizeof(pid_t);
 529         else if (synth_field_is_string(type))
 530                 size = synth_field_string_size(type);
 531
 532         return size;
 533 }
 534
 535 static const char *synth_field_fmt(char *type)
 536 {
 537         const char *fmt = "%llu";
 538
 539         if (strcmp(type, "s64") == 0)
 540                 fmt = "%lld";
 541         else if (strcmp(type, "u64") == 0)
 542                 fmt = "%llu";
 543         else if (strcmp(type, "s32") == 0)
 544                 fmt = "%d";
 545         else if (strcmp(type, "u32") == 0)
 546                 fmt = "%u";
 547         else if (strcmp(type, "s16") == 0)
 548                 fmt = "%d";
 549         else if (strcmp(type, "u16") == 0)
 550                 fmt = "%u";
 551         else if (strcmp(type, "s8") == 0)
 552                 fmt = "%d";
 553         else if (strcmp(type, "u8") == 0)
 554                 fmt = "%u";
 555         else if (strcmp(type, "char") == 0)
 556                 fmt = "%d";
 557         else if (strcmp(type, "unsigned char") == 0)
 558                 fmt = "%u";
 559         else if (strcmp(type, "int") == 0)
 560                 fmt = "%d";
 561         else if (strcmp(type, "unsigned int") == 0)
 562                 fmt = "%u";
 563         else if (strcmp(type, "long") == 0)
 564                 fmt = "%ld";
 565         else if (strcmp(type, "unsigned long") == 0)
 566                 fmt = "%lu";
 567         else if (strcmp(type, "pid_t") == 0)
 568                 fmt = "%d";
 569         else if (synth_field_is_string(type))
 570                 fmt = "%s";
 571
 572         return fmt;
 573 }
 574
 575 static enum print_line_t print_synth_event(struct trace_iterator *iter,
 576                                            int flags,
 577                                            struct trace_event *event)
 578 {
 579         struct trace_array *tr = iter->tr;
 580         struct trace_seq *s = &iter->seq;
 581         struct synth_trace_event *entry;
 582         struct synth_event *se;
 583         unsigned int i, n_u64;
 584         char print_fmt[32];
 585         const char *fmt;
 586
 587         entry = (struct synth_trace_event *)iter->ent;
 588         se = container_of(event, struct synth_event, call.event);
 589
 590         trace_seq_printf(s, "%s: ", se->name);
 591
 592         for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
 593                 if (trace_seq_has_overflowed(s))
 594                         goto end;
 595
 596                 fmt = synth_field_fmt(se->fields[i]->type);
 597
 598                 /* parameter types */
 599                 if (tr->trace_flags & TRACE_ITER_VERBOSE)
 600                         trace_seq_printf(s, "%s ", fmt);
 601
 602                 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
 603
 604                 /* parameter values */
 605                 if (se->fields[i]->is_string) {
 606                         trace_seq_printf(s, print_fmt, se->fields[i]->name,
 607                                          (char *)&entry->fields[n_u64],
 608                                          i == se->n_fields - 1 ? "" : " ");
 609                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 610                 } else {
 611                         trace_seq_printf(s, print_fmt, se->fields[i]->name,
 612                                          entry->fields[n_u64],
 613                                          i == se->n_fields - 1 ? "" : " ");
 614                         n_u64++;
 615                 }
 616         }
 617 end:
 618         trace_seq_putc(s, '\n');
 619
 620         return trace_handle_return(s);
 621 }
 622
 623 static struct trace_event_functions synth_event_funcs = {
 624         .trace          = print_synth_event
 625 };
 626
 627 static notrace void trace_event_raw_event_synth(void *__data,
 628                                                 u64 *var_ref_vals,
 629                                                 unsigned int var_ref_idx)
 630 {
 631         struct trace_event_file *trace_file = __data;
 632         struct synth_trace_event *entry;
 633         struct trace_event_buffer fbuffer;
 634         struct ring_buffer *buffer;
 635         struct synth_event *event;
 636         unsigned int i, n_u64;
 637         int fields_size = 0;
 638
 639         event = trace_file->event_call->data;
 640
 641         if (trace_trigger_soft_disabled(trace_file))
 642                 return;
 643
 644         fields_size = event->n_u64 * sizeof(u64);
 645
 646         /*
 647          * Avoid ring buffer recursion detection, as this event
 648          * is being performed within another event.
 649          */
 650         buffer = trace_file->tr->trace_buffer.buffer;
 651         ring_buffer_nest_start(buffer);
 652
 653         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 654                                            sizeof(*entry) + fields_size);
 655         if (!entry)
 656                 goto out;
 657
 658         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 659                 if (event->fields[i]->is_string) {
 660                         char *str_val = (char *)(long)var_ref_vals[var_ref_idx + i];
 661                         char *str_field = (char *)&entry->fields[n_u64];
 662
 663                         strscpy(str_field, str_val, STR_VAR_LEN_MAX);
 664                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 665                 } else {
 666                         entry->fields[n_u64] = var_ref_vals[var_ref_idx + i];
 667                         n_u64++;
 668                 }
 669         }
 670
 671         trace_event_buffer_commit(&fbuffer);
 672 out:
 673         ring_buffer_nest_end(buffer);
 674 }
 675
 676 static void free_synth_event_print_fmt(struct trace_event_call *call)
 677 {
 678         if (call) {
 679                 kfree(call->print_fmt);
 680                 call->print_fmt = NULL;
 681         }
 682 }
 683
 684 static int __set_synth_event_print_fmt(struct synth_event *event,
 685                                        char *buf, int len)
 686 {
 687         const char *fmt;
 688         int pos = 0;
 689         int i;
 690
 691         /* When len=0, we just calculate the needed length */
 692 #define LEN_OR_ZERO (len ? len - pos : 0)
 693
 694         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 695         for (i = 0; i < event->n_fields; i++) {
 696                 fmt = synth_field_fmt(event->fields[i]->type);
 697                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 698                                 event->fields[i]->name, fmt,
 699                                 i == event->n_fields - 1 ? "" : ", ");
 700         }
 701         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 702
 703         for (i = 0; i < event->n_fields; i++) {
 704                 pos += snprintf(buf + pos, LEN_OR_ZERO,
 705                                 ", REC->%s", event->fields[i]->name);
 706         }
 707
 708 #undef LEN_OR_ZERO
 709
 710         /* return the length of print_fmt */
 711         return pos;
 712 }
 713
 714 static int set_synth_event_print_fmt(struct trace_event_call *call)
 715 {
 716         struct synth_event *event = call->data;
 717         char *print_fmt;
 718         int len;
 719
 720         /* First: called with 0 length to calculate the needed length */
 721         len = __set_synth_event_print_fmt(event, NULL, 0);
 722
 723         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 724         if (!print_fmt)
 725                 return -ENOMEM;
 726
 727         /* Second: actually write the @print_fmt */
 728         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 729         call->print_fmt = print_fmt;
 730
 731         return 0;
 732 }
 733
 734 static void free_synth_field(struct synth_field *field)
 735 {
 736         kfree(field->type);
 737         kfree(field->name);
 738         kfree(field);
 739 }
 740
 741 static struct synth_field *parse_synth_field(int argc, char **argv,
 742                                              int *consumed)
 743 {
 744         struct synth_field *field;
 745         const char *prefix = NULL;
 746         char *field_type = argv[0], *field_name;
 747         int len, ret = 0;
 748         char *array;
 749
 750         if (field_type[0] == ';')
 751                 field_type++;
 752
 753         if (!strcmp(field_type, "unsigned")) {
 754                 if (argc < 3)
 755                         return ERR_PTR(-EINVAL);
 756                 prefix = "unsigned ";
 757                 field_type = argv[1];
 758                 field_name = argv[2];
 759                 *consumed = 3;
 760         } else {
 761                 field_name = argv[1];
 762                 *consumed = 2;
 763         }
 764
 765         len = strlen(field_name);
 766         if (field_name[len - 1] == ';')
 767                 field_name[len - 1] = '\0';
 768
 769         field = kzalloc(sizeof(*field), GFP_KERNEL);
 770         if (!field)
 771                 return ERR_PTR(-ENOMEM);
 772
 773         len = strlen(field_type) + 1;
 774         array = strchr(field_name, '[');
 775         if (array)
 776                 len += strlen(array);
 777         if (prefix)
 778                 len += strlen(prefix);
 779         field->type = kzalloc(len, GFP_KERNEL);
 780         if (!field->type) {
 781                 ret = -ENOMEM;
 782                 goto free;
 783         }
 784         if (prefix)
 785                 strcat(field->type, prefix);
 786         strcat(field->type, field_type);
 787         if (array) {
 788                 strcat(field->type, array);
 789                 *array = '\0';
 790         }
 791
 792         field->size = synth_field_size(field->type);
 793         if (!field->size) {
 794                 ret = -EINVAL;
 795                 goto free;
 796         }
 797
 798         if (synth_field_is_string(field->type))
 799                 field->is_string = true;
 800
 801         field->is_signed = synth_field_signed(field->type);
 802
 803         field->name = kstrdup(field_name, GFP_KERNEL);
 804         if (!field->name) {
 805                 ret = -ENOMEM;
 806                 goto free;
 807         }
 808  out:
 809         return field;
 810  free:
 811         free_synth_field(field);
 812         field = ERR_PTR(ret);
 813         goto out;
 814 }
 815
 816 static void free_synth_tracepoint(struct tracepoint *tp)
 817 {
 818         if (!tp)
 819                 return;
 820
 821         kfree(tp->name);
 822         kfree(tp);
 823 }
 824
 825 static struct tracepoint *alloc_synth_tracepoint(char *name)
 826 {
 827         struct tracepoint *tp;
 828
 829         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 830         if (!tp)
 831                 return ERR_PTR(-ENOMEM);
 832
 833         tp->name = kstrdup(name, GFP_KERNEL);
 834         if (!tp->name) {
 835                 kfree(tp);
 836                 return ERR_PTR(-ENOMEM);
 837         }
 838
 839         return tp;
 840 }
 841
 842 typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
 843                                     unsigned int var_ref_idx);
 844
 845 static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
 846                                unsigned int var_ref_idx)
 847 {
 848         struct tracepoint *tp = event->tp;
 849
 850         if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
 851                 struct tracepoint_func *probe_func_ptr;
 852                 synth_probe_func_t probe_func;
 853                 void *__data;
 854
 855                 if (!(cpu_online(raw_smp_processor_id())))
 856                         return;
 857
 858                 probe_func_ptr = rcu_dereference_sched((tp)->funcs);
 859                 if (probe_func_ptr) {
 860                         do {
 861                                 probe_func = probe_func_ptr->func;
 862                                 __data = probe_func_ptr->data;
 863                                 probe_func(__data, var_ref_vals, var_ref_idx);
 864                         } while ((++probe_func_ptr)->func);
 865                 }
 866         }
 867 }
 868
 869 static struct synth_event *find_synth_event(const char *name)
 870 {
 871         struct synth_event *event;
 872
 873         list_for_each_entry(event, &synth_event_list, list) {
 874                 if (strcmp(event->name, name) == 0)
 875                         return event;
 876         }
 877
 878         return NULL;
 879 }
 880
 881 static int register_synth_event(struct synth_event *event)
 882 {
 883         struct trace_event_call *call = &event->call;
 884         int ret = 0;
 885
 886         event->call.class = &event->class;
 887         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 888         if (!event->class.system) {
 889                 ret = -ENOMEM;
 890                 goto out;
 891         }
 892
 893         event->tp = alloc_synth_tracepoint(event->name);
 894         if (IS_ERR(event->tp)) {
 895                 ret = PTR_ERR(event->tp);
 896                 event->tp = NULL;
 897                 goto out;
 898         }
 899
 900         INIT_LIST_HEAD(&call->class->fields);
 901         call->event.funcs = &synth_event_funcs;
 902         call->class->define_fields = synth_event_define_fields;
 903
 904         ret = register_trace_event(&call->event);
 905         if (!ret) {
 906                 ret = -ENODEV;
 907                 goto out;
 908         }
 909         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 910         call->class->reg = trace_event_reg;
 911         call->class->probe = trace_event_raw_event_synth;
 912         call->data = event;
 913         call->tp = event->tp;
 914
 915         ret = trace_add_event_call(call);
 916         if (ret) {
 917                 pr_warn("Failed to register synthetic event: %s\n",
 918                         trace_event_name(call));
 919                 goto err;
 920         }
 921
 922         ret = set_synth_event_print_fmt(call);
 923         if (ret < 0) {
 924                 trace_remove_event_call(call);
 925                 goto err;
 926         }
 927  out:
 928         return ret;
 929  err:
 930         unregister_trace_event(&call->event);
 931         goto out;
 932 }
 933
 934 static int unregister_synth_event(struct synth_event *event)
 935 {
 936         struct trace_event_call *call = &event->call;
 937         int ret;
 938
 939         ret = trace_remove_event_call(call);
 940
 941         return ret;
 942 }
 943
 944 static void free_synth_event(struct synth_event *event)
 945 {
 946         unsigned int i;
 947
 948         if (!event)
 949                 return;
 950
 951         for (i = 0; i < event->n_fields; i++)
 952                 free_synth_field(event->fields[i]);
 953
 954         kfree(event->fields);
 955         kfree(event->name);
 956         kfree(event->class.system);
 957         free_synth_tracepoint(event->tp);
 958         free_synth_event_print_fmt(&event->call);
 959         kfree(event);
 960 }
 961
 962 static struct synth_event *alloc_synth_event(char *event_name, int n_fields,
 963                                              struct synth_field **fields)
 964 {
 965         struct synth_event *event;
 966         unsigned int i;
 967
 968         event = kzalloc(sizeof(*event), GFP_KERNEL);
 969         if (!event) {
 970                 event = ERR_PTR(-ENOMEM);
 971                 goto out;
 972         }
 973
 974         event->name = kstrdup(event_name, GFP_KERNEL);
 975         if (!event->name) {
 976                 kfree(event);
 977                 event = ERR_PTR(-ENOMEM);
 978                 goto out;
 979         }
 980
 981         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 982         if (!event->fields) {
 983                 free_synth_event(event);
 984                 event = ERR_PTR(-ENOMEM);
 985                 goto out;
 986         }
 987
 988         for (i = 0; i < n_fields; i++)
 989                 event->fields[i] = fields[i];
 990
 991         event->n_fields = n_fields;
 992  out:
 993         return event;
 994 }
 995
 996 static void action_trace(struct hist_trigger_data *hist_data,
 997                          struct tracing_map_elt *elt, void *rec,
 998                          struct ring_buffer_event *rbe,
 999                          struct action_data *data, u64 *var_ref_vals)
1000 {
1001         struct synth_event *event = data->onmatch.synth_event;
1002
1003         trace_synth(event, var_ref_vals, data->onmatch.var_ref_idx);
1004 }
1005
1006 struct hist_var_data {
1007         struct list_head list;
1008         struct hist_trigger_data *hist_data;
1009 };
1010
1011 static void add_or_delete_synth_event(struct synth_event *event, int delete)
1012 {
1013         if (delete)
1014                 free_synth_event(event);
1015         else {
1016                 mutex_lock(&synth_event_mutex);
1017                 if (!find_synth_event(event->name))
1018                         list_add(&event->list, &synth_event_list);
1019                 else
1020                         free_synth_event(event);
1021                 mutex_unlock(&synth_event_mutex);
1022         }
1023 }
1024
1025 static int create_synth_event(int argc, char **argv)
1026 {
1027         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1028         struct synth_event *event = NULL;
1029         bool delete_event = false;
1030         int i, consumed = 0, n_fields = 0, ret = 0;
1031         char *name;
1032
1033         mutex_lock(&synth_event_mutex);
1034
1035         /*
1036          * Argument syntax:
1037          *  - Add synthetic event: <event_name> field[;field] ...
1038          *  - Remove synthetic event: !<event_name> field[;field] ...
1039          *      where 'field' = type field_name
1040          */
1041         if (argc < 1) {
1042                 ret = -EINVAL;
1043                 goto out;
1044         }
1045
1046         name = argv[0];
1047         if (name[0] == '!') {
1048                 delete_event = true;
1049                 name++;
1050         }
1051
1052         event = find_synth_event(name);
1053         if (event) {
1054                 if (delete_event) {
1055                         if (event->ref) {
1056                                 event = NULL;
1057                                 ret = -EBUSY;
1058                                 goto out;
1059                         }
1060                         list_del(&event->list);
1061                         goto out;
1062                 }
1063                 event = NULL;
1064                 ret = -EEXIST;
1065                 goto out;
1066         } else if (delete_event)
1067                 goto out;
1068
1069         if (argc < 2) {
1070                 ret = -EINVAL;
1071                 goto out;
1072         }
1073
1074         for (i = 1; i < argc - 1; i++) {
1075                 if (strcmp(argv[i], ";") == 0)
1076                         continue;
1077                 if (n_fields == SYNTH_FIELDS_MAX) {
1078                         ret = -EINVAL;
1079                         goto err;
1080                 }
1081
1082                 field = parse_synth_field(argc - i, &argv[i], &consumed);
1083                 if (IS_ERR(field)) {
1084                         ret = PTR_ERR(field);
1085                         goto err;
1086                 }
1087                 fields[n_fields++] = field;
1088                 i += consumed - 1;
1089         }
1090
1091         if (i < argc && strcmp(argv[i], ";") != 0) {
1092                 ret = -EINVAL;
1093                 goto err;
1094         }
1095
1096         event = alloc_synth_event(name, n_fields, fields);
1097         if (IS_ERR(event)) {
1098                 ret = PTR_ERR(event);
1099                 event = NULL;
1100                 goto err;
1101         }
1102  out:
1103         mutex_unlock(&synth_event_mutex);
1104
1105         if (event) {
1106                 if (delete_event) {
1107                         ret = unregister_synth_event(event);
1108                         add_or_delete_synth_event(event, !ret);
1109                 } else {
1110                         ret = register_synth_event(event);
1111                         add_or_delete_synth_event(event, ret);
1112                 }
1113         }
1114
1115         return ret;
1116  err:
1117         mutex_unlock(&synth_event_mutex);
1118
1119         for (i = 0; i < n_fields; i++)
1120                 free_synth_field(fields[i]);
1121         free_synth_event(event);
1122
1123         return ret;
1124 }
1125
1126 static int release_all_synth_events(void)
1127 {
1128         struct list_head release_events;
1129         struct synth_event *event, *e;
1130         int ret = 0;
1131
1132         INIT_LIST_HEAD(&release_events);
1133
1134         mutex_lock(&synth_event_mutex);
1135
1136         list_for_each_entry(event, &synth_event_list, list) {
1137                 if (event->ref) {
1138                         mutex_unlock(&synth_event_mutex);
1139                         return -EBUSY;
1140                 }
1141         }
1142
1143         list_splice_init(&event->list, &release_events);
1144
1145         mutex_unlock(&synth_event_mutex);
1146
1147         list_for_each_entry_safe(event, e, &release_events, list) {
1148                 list_del(&event->list);
1149
1150                 ret = unregister_synth_event(event);
1151                 add_or_delete_synth_event(event, !ret);
1152         }
1153
1154         return ret;
1155 }
1156
1157
1158 static void *synth_events_seq_start(struct seq_file *m, loff_t *pos)
1159 {
1160         mutex_lock(&synth_event_mutex);
1161
1162         return seq_list_start(&synth_event_list, *pos);
1163 }
1164
1165 static void *synth_events_seq_next(struct seq_file *m, void *v, loff_t *pos)
1166 {
1167         return seq_list_next(v, &synth_event_list, pos);
1168 }
1169
1170 static void synth_events_seq_stop(struct seq_file *m, void *v)
1171 {
1172         mutex_unlock(&synth_event_mutex);
1173 }
1174
1175 static int synth_events_seq_show(struct seq_file *m, void *v)
1176 {
1177         struct synth_field *field;
1178         struct synth_event *event = v;
1179         unsigned int i;
1180
1181         seq_printf(m, "%s\t", event->name);
1182
1183         for (i = 0; i < event->n_fields; i++) {
1184                 field = event->fields[i];
1185
1186                 /* parameter values */
1187                 seq_printf(m, "%s %s%s", field->type, field->name,
1188                            i == event->n_fields - 1 ? "" : "; ");
1189         }
1190
1191         seq_putc(m, '\n');
1192
1193         return 0;
1194 }
1195
1196 static const struct seq_operations synth_events_seq_op = {
1197         .start  = synth_events_seq_start,
1198         .next   = synth_events_seq_next,
1199         .stop   = synth_events_seq_stop,
1200         .show   = synth_events_seq_show
1201 };
1202
1203 static int synth_events_open(struct inode *inode, struct file *file)
1204 {
1205         int ret;
1206
1207         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1208                 ret = release_all_synth_events();
1209                 if (ret < 0)
1210                         return ret;
1211         }
1212
1213         return seq_open(file, &synth_events_seq_op);
1214 }
1215
1216 static ssize_t synth_events_write(struct file *file,
1217                                   const char __user *buffer,
1218                                   size_t count, loff_t *ppos)
1219 {
1220         return trace_parse_run_command(file, buffer, count, ppos,
1221                                        create_synth_event);
1222 }
1223
1224 static const struct file_operations synth_events_fops = {
1225         .open           = synth_events_open,
1226         .write          = synth_events_write,
1227         .read           = seq_read,
1228         .llseek         = seq_lseek,
1229         .release        = seq_release,
1230 };
1231
1232 static u64 hist_field_timestamp(struct hist_field *hist_field,
1233                                 struct tracing_map_elt *elt,
1234                                 struct ring_buffer_event *rbe,
1235                                 void *event)
1236 {
1237         struct hist_trigger_data *hist_data = hist_field->hist_data;
1238         struct trace_array *tr = hist_data->event_file->tr;
1239
1240         u64 ts = ring_buffer_event_time_stamp(rbe);
1241
1242         if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
1243                 ts = ns2usecs(ts);
1244
1245         return ts;
1246 }
1247
1248 static u64 hist_field_cpu(struct hist_field *hist_field,
1249                           struct tracing_map_elt *elt,
1250                           struct ring_buffer_event *rbe,
1251                           void *event)
1252 {
1253         int cpu = smp_processor_id();
1254
1255         return cpu;
1256 }
1257
1258 static struct hist_field *
1259 check_field_for_var_ref(struct hist_field *hist_field,
1260                         struct hist_trigger_data *var_data,
1261                         unsigned int var_idx)
1262 {
1263         struct hist_field *found = NULL;
1264
1265         if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF) {
1266                 if (hist_field->var.idx == var_idx &&
1267                     hist_field->var.hist_data == var_data) {
1268                         found = hist_field;
1269                 }
1270         }
1271
1272         return found;
1273 }
1274
1275 static struct hist_field *
1276 check_field_for_var_refs(struct hist_trigger_data *hist_data,
1277                          struct hist_field *hist_field,
1278                          struct hist_trigger_data *var_data,
1279                          unsigned int var_idx,
1280                          unsigned int level)
1281 {
1282         struct hist_field *found = NULL;
1283         unsigned int i;
1284
1285         if (level > 3)
1286                 return found;
1287
1288         if (!hist_field)
1289                 return found;
1290
1291         found = check_field_for_var_ref(hist_field, var_data, var_idx);
1292         if (found)
1293                 return found;
1294
1295         for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
1296                 struct hist_field *operand;
1297
1298                 operand = hist_field->operands[i];
1299                 found = check_field_for_var_refs(hist_data, operand, var_data,
1300                                                  var_idx, level + 1);
1301                 if (found)
1302                         return found;
1303         }
1304
1305         return found;
1306 }
1307
1308 static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
1309                                        struct hist_trigger_data *var_data,
1310                                        unsigned int var_idx)
1311 {
1312         struct hist_field *hist_field, *found = NULL;
1313         unsigned int i;
1314
1315         for_each_hist_field(i, hist_data) {
1316                 hist_field = hist_data->fields[i];
1317                 found = check_field_for_var_refs(hist_data, hist_field,
1318                                                  var_data, var_idx, 0);
1319                 if (found)
1320                         return found;
1321         }
1322
1323         for (i = 0; i < hist_data->n_synth_var_refs; i++) {
1324                 hist_field = hist_data->synth_var_refs[i];
1325                 found = check_field_for_var_refs(hist_data, hist_field,
1326                                                  var_data, var_idx, 0);
1327                 if (found)
1328                         return found;
1329         }
1330
1331         return found;
1332 }
1333
1334 static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
1335                                            unsigned int var_idx)
1336 {
1337         struct trace_array *tr = hist_data->event_file->tr;
1338         struct hist_field *found = NULL;
1339         struct hist_var_data *var_data;
1340
1341         list_for_each_entry(var_data, &tr->hist_vars, list) {
1342                 if (var_data->hist_data == hist_data)
1343                         continue;
1344                 found = find_var_ref(var_data->hist_data, hist_data, var_idx);
1345                 if (found)
1346                         break;
1347         }
1348
1349         return found;
1350 }
1351
1352 static bool check_var_refs(struct hist_trigger_data *hist_data)
1353 {
1354         struct hist_field *field;
1355         bool found = false;
1356         int i;
1357
1358         for_each_hist_field(i, hist_data) {
1359                 field = hist_data->fields[i];
1360                 if (field && field->flags & HIST_FIELD_FL_VAR) {
1361                         if (find_any_var_ref(hist_data, field->var.idx)) {
1362                                 found = true;
1363                                 break;
1364                         }
1365                 }
1366         }
1367
1368         return found;
1369 }
1370
1371 static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
1372 {
1373         struct trace_array *tr = hist_data->event_file->tr;
1374         struct hist_var_data *var_data, *found = NULL;
1375
1376         list_for_each_entry(var_data, &tr->hist_vars, list) {
1377                 if (var_data->hist_data == hist_data) {
1378                         found = var_data;
1379                         break;
1380                 }
1381         }
1382
1383         return found;
1384 }
1385
1386 static bool field_has_hist_vars(struct hist_field *hist_field,
1387                                 unsigned int level)
1388 {
1389         int i;
1390
1391         if (level > 3)
1392                 return false;
1393
1394         if (!hist_field)
1395                 return false;
1396
1397         if (hist_field->flags & HIST_FIELD_FL_VAR ||
1398             hist_field->flags & HIST_FIELD_FL_VAR_REF)
1399                 return true;
1400
1401         for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
1402                 struct hist_field *operand;
1403
1404                 operand = hist_field->operands[i];
1405                 if (field_has_hist_vars(operand, level + 1))
1406                         return true;
1407         }
1408
1409         return false;
1410 }
1411
1412 static bool has_hist_vars(struct hist_trigger_data *hist_data)
1413 {
1414         struct hist_field *hist_field;
1415         int i;
1416
1417         for_each_hist_field(i, hist_data) {
1418                 hist_field = hist_data->fields[i];
1419                 if (field_has_hist_vars(hist_field, 0))
1420                         return true;
1421         }
1422
1423         return false;
1424 }
1425
1426 static int save_hist_vars(struct hist_trigger_data *hist_data)
1427 {
1428         struct trace_array *tr = hist_data->event_file->tr;
1429         struct hist_var_data *var_data;
1430
1431         var_data = find_hist_vars(hist_data);
1432         if (var_data)
1433                 return 0;
1434
1435         if (trace_array_get(tr) < 0)
1436                 return -ENODEV;
1437
1438         var_data = kzalloc(sizeof(*var_data), GFP_KERNEL);
1439         if (!var_data) {
1440                 trace_array_put(tr);
1441                 return -ENOMEM;
1442         }
1443
1444         var_data->hist_data = hist_data;
1445         list_add(&var_data->list, &tr->hist_vars);
1446
1447         return 0;
1448 }
1449
1450 static void remove_hist_vars(struct hist_trigger_data *hist_data)
1451 {
1452         struct trace_array *tr = hist_data->event_file->tr;
1453         struct hist_var_data *var_data;
1454
1455         var_data = find_hist_vars(hist_data);
1456         if (!var_data)
1457                 return;
1458
1459         if (WARN_ON(check_var_refs(hist_data)))
1460                 return;
1461
1462         list_del(&var_data->list);
1463
1464         kfree(var_data);
1465
1466         trace_array_put(tr);
1467 }
1468
1469 static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
1470                                          const char *var_name)
1471 {
1472         struct hist_field *hist_field, *found = NULL;
1473         int i;
1474
1475         for_each_hist_field(i, hist_data) {
1476                 hist_field = hist_data->fields[i];
1477                 if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
1478                     strcmp(hist_field->var.name, var_name) == 0) {
1479                         found = hist_field;
1480                         break;
1481                 }
1482         }
1483
1484         return found;
1485 }
1486
1487 static struct hist_field *find_var(struct hist_trigger_data *hist_data,
1488                                    struct trace_event_file *file,
1489                                    const char *var_name)
1490 {
1491         struct hist_trigger_data *test_data;
1492         struct event_trigger_data *test;
1493         struct hist_field *hist_field;
1494
1495         hist_field = find_var_field(hist_data, var_name);
1496         if (hist_field)
1497                 return hist_field;
1498
1499         list_for_each_entry_rcu(test, &file->triggers, list) {
1500                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1501                         test_data = test->private_data;
1502                         hist_field = find_var_field(test_data, var_name);
1503                         if (hist_field)
1504                                 return hist_field;
1505                 }
1506         }
1507
1508         return NULL;
1509 }
1510
1511 static struct trace_event_file *find_var_file(struct trace_array *tr,
1512                                               char *system,
1513                                               char *event_name,
1514                                               char *var_name)
1515 {
1516         struct hist_trigger_data *var_hist_data;
1517         struct hist_var_data *var_data;
1518         struct trace_event_file *file, *found = NULL;
1519
1520         if (system)
1521                 return find_event_file(tr, system, event_name);
1522
1523         list_for_each_entry(var_data, &tr->hist_vars, list) {
1524                 var_hist_data = var_data->hist_data;
1525                 file = var_hist_data->event_file;
1526                 if (file == found)
1527                         continue;
1528
1529                 if (find_var_field(var_hist_data, var_name)) {
1530                         if (found) {
1531                                 hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
1532                                 return NULL;
1533                         }
1534
1535                         found = file;
1536                 }
1537         }
1538
1539         return found;
1540 }
1541
1542 static struct hist_field *find_file_var(struct trace_event_file *file,
1543                                         const char *var_name)
1544 {
1545         struct hist_trigger_data *test_data;
1546         struct event_trigger_data *test;
1547         struct hist_field *hist_field;
1548
1549         list_for_each_entry_rcu(test, &file->triggers, list) {
1550                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1551                         test_data = test->private_data;
1552                         hist_field = find_var_field(test_data, var_name);
1553                         if (hist_field)
1554                                 return hist_field;
1555                 }
1556         }
1557
1558         return NULL;
1559 }
1560
1561 static struct hist_field *
1562 find_match_var(struct hist_trigger_data *hist_data, char *var_name)
1563 {
1564         struct trace_array *tr = hist_data->event_file->tr;
1565         struct hist_field *hist_field, *found = NULL;
1566         struct trace_event_file *file;
1567         unsigned int i;
1568
1569         for (i = 0; i < hist_data->n_actions; i++) {
1570                 struct action_data *data = hist_data->actions[i];
1571
1572                 if (data->fn == action_trace) {
1573                         char *system = data->onmatch.match_event_system;
1574                         char *event_name = data->onmatch.match_event;
1575
1576                         file = find_var_file(tr, system, event_name, var_name);
1577                         if (!file)
1578                                 continue;
1579                         hist_field = find_file_var(file, var_name);
1580                         if (hist_field) {
1581                                 if (found) {
1582                                         hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
1583                                         return ERR_PTR(-EINVAL);
1584                                 }
1585
1586                                 found = hist_field;
1587                         }
1588                 }
1589         }
1590         return found;
1591 }
1592
1593 static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
1594                                          char *system,
1595                                          char *event_name,
1596                                          char *var_name)
1597 {
1598         struct trace_array *tr = hist_data->event_file->tr;
1599         struct hist_field *hist_field = NULL;
1600         struct trace_event_file *file;
1601
1602         if (!system || !event_name) {
1603                 hist_field = find_match_var(hist_data, var_name);
1604                 if (IS_ERR(hist_field))
1605                         return NULL;
1606                 if (hist_field)
1607                         return hist_field;
1608         }
1609
1610         file = find_var_file(tr, system, event_name, var_name);
1611         if (!file)
1612                 return NULL;
1613
1614         hist_field = find_file_var(file, var_name);
1615
1616         return hist_field;
1617 }
1618
1619 struct hist_elt_data {
1620         char *comm;
1621         u64 *var_ref_vals;
1622         char *field_var_str[SYNTH_FIELDS_MAX];
1623 };
1624
1625 static u64 hist_field_var_ref(struct hist_field *hist_field,
1626                               struct tracing_map_elt *elt,
1627                               struct ring_buffer_event *rbe,
1628                               void *event)
1629 {
1630         struct hist_elt_data *elt_data;
1631         u64 var_val = 0;
1632
1633         elt_data = elt->private_data;
1634         var_val = elt_data->var_ref_vals[hist_field->var_ref_idx];
1635
1636         return var_val;
1637 }
1638
1639 static bool resolve_var_refs(struct hist_trigger_data *hist_data, void *key,
1640                              u64 *var_ref_vals, bool self)
1641 {
1642         struct hist_trigger_data *var_data;
1643         struct tracing_map_elt *var_elt;
1644         struct hist_field *hist_field;
1645         unsigned int i, var_idx;
1646         bool resolved = true;
1647         u64 var_val = 0;
1648
1649         for (i = 0; i < hist_data->n_var_refs; i++) {
1650                 hist_field = hist_data->var_refs[i];
1651                 var_idx = hist_field->var.idx;
1652                 var_data = hist_field->var.hist_data;
1653
1654                 if (var_data == NULL) {
1655                         resolved = false;
1656                         break;
1657                 }
1658
1659                 if ((self && var_data != hist_data) ||
1660                     (!self && var_data == hist_data))
1661                         continue;
1662
1663                 var_elt = tracing_map_lookup(var_data->map, key);
1664                 if (!var_elt) {
1665                         resolved = false;
1666                         break;
1667                 }
1668
1669                 if (!tracing_map_var_set(var_elt, var_idx)) {
1670                         resolved = false;
1671                         break;
1672                 }
1673
1674                 if (self || !hist_field->read_once)
1675                         var_val = tracing_map_read_var(var_elt, var_idx);
1676                 else
1677                         var_val = tracing_map_read_var_once(var_elt, var_idx);
1678
1679                 var_ref_vals[i] = var_val;
1680         }
1681
1682         return resolved;
1683 }
1684
1685 static const char *hist_field_name(struct hist_field *field,
1686                                    unsigned int level)
1687 {
1688         const char *field_name = "";
1689
1690         if (level > 1)
1691                 return field_name;
1692
1693         if (field->field)
1694                 field_name = field->field->name;
1695         else if (field->flags & HIST_FIELD_FL_LOG2 ||
1696                  field->flags & HIST_FIELD_FL_ALIAS)
1697                 field_name = hist_field_name(field->operands[0], ++level);
1698         else if (field->flags & HIST_FIELD_FL_CPU)
1699                 field_name = "cpu";
1700         else if (field->flags & HIST_FIELD_FL_EXPR ||
1701                  field->flags & HIST_FIELD_FL_VAR_REF) {
1702                 if (field->system) {
1703                         static char full_name[MAX_FILTER_STR_VAL];
1704
1705                         strcat(full_name, field->system);
1706                         strcat(full_name, ".");
1707                         strcat(full_name, field->event_name);
1708                         strcat(full_name, ".");
1709                         strcat(full_name, field->name);
1710                         field_name = full_name;
1711                 } else
1712                         field_name = field->name;
1713         } else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
1714                 field_name = "common_timestamp";
1715
1716         if (field_name == NULL)
1717                 field_name = "";
1718
1719         return field_name;
1720 }
1721
1722 static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
1723 {
1724         hist_field_fn_t fn = NULL;
1725
1726         switch (field_size) {
1727         case 8:
1728                 if (field_is_signed)
1729                         fn = hist_field_s64;
1730                 else
1731                         fn = hist_field_u64;
1732                 break;
1733         case 4:
1734                 if (field_is_signed)
1735                         fn = hist_field_s32;
1736                 else
1737                         fn = hist_field_u32;
1738                 break;
1739         case 2:
1740                 if (field_is_signed)
1741                         fn = hist_field_s16;
1742                 else
1743                         fn = hist_field_u16;
1744                 break;
1745         case 1:
1746                 if (field_is_signed)
1747                         fn = hist_field_s8;
1748                 else
1749                         fn = hist_field_u8;
1750                 break;
1751         }
1752
1753         return fn;
1754 }
1755
1756 static int parse_map_size(char *str)
1757 {
1758         unsigned long size, map_bits;
1759         int ret;
1760
1761         strsep(&str, "=");
1762         if (!str) {
1763                 ret = -EINVAL;
1764                 goto out;
1765         }
1766
1767         ret = kstrtoul(str, 0, &size);
1768         if (ret)
1769                 goto out;
1770
1771         map_bits = ilog2(roundup_pow_of_two(size));
1772         if (map_bits < TRACING_MAP_BITS_MIN ||
1773             map_bits > TRACING_MAP_BITS_MAX)
1774                 ret = -EINVAL;
1775         else
1776                 ret = map_bits;
1777  out:
1778         return ret;
1779 }
1780
1781 static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
1782 {
1783         unsigned int i;
1784
1785         if (!attrs)
1786                 return;
1787
1788         for (i = 0; i < attrs->n_assignments; i++)
1789                 kfree(attrs->assignment_str[i]);
1790
1791         for (i = 0; i < attrs->n_actions; i++)
1792                 kfree(attrs->action_str[i]);
1793
1794         kfree(attrs->name);
1795         kfree(attrs->sort_key_str);
1796         kfree(attrs->keys_str);
1797         kfree(attrs->vals_str);
1798         kfree(attrs->clock);
1799         kfree(attrs);
1800 }
1801
1802 static int parse_action(char *str, struct hist_trigger_attrs *attrs)
1803 {
1804         int ret = -EINVAL;
1805
1806         if (attrs->n_actions >= HIST_ACTIONS_MAX)
1807                 return ret;
1808
1809         if ((strncmp(str, "onmatch(", strlen("onmatch(")) == 0) ||
1810             (strncmp(str, "onmax(", strlen("onmax(")) == 0)) {
1811                 attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
1812                 if (!attrs->action_str[attrs->n_actions]) {
1813                         ret = -ENOMEM;
1814                         return ret;
1815                 }
1816                 attrs->n_actions++;
1817                 ret = 0;
1818         }
1819
1820         return ret;
1821 }
1822
1823 static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
1824 {
1825         int ret = 0;
1826
1827         if ((strncmp(str, "key=", strlen("key=")) == 0) ||
1828             (strncmp(str, "keys=", strlen("keys=")) == 0)) {
1829                 attrs->keys_str = kstrdup(str, GFP_KERNEL);
1830                 if (!attrs->keys_str) {
1831                         ret = -ENOMEM;
1832                         goto out;
1833                 }
1834         } else if ((strncmp(str, "val=", strlen("val=")) == 0) ||
1835                  (strncmp(str, "vals=", strlen("vals=")) == 0) ||
1836                  (strncmp(str, "values=", strlen("values=")) == 0)) {
1837                 attrs->vals_str = kstrdup(str, GFP_KERNEL);
1838                 if (!attrs->vals_str) {
1839                         ret = -ENOMEM;
1840                         goto out;
1841                 }
1842         } else if (strncmp(str, "sort=", strlen("sort=")) == 0) {
1843                 attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
1844                 if (!attrs->sort_key_str) {
1845                         ret = -ENOMEM;
1846                         goto out;
1847                 }
1848         } else if (strncmp(str, "name=", strlen("name=")) == 0) {
1849                 attrs->name = kstrdup(str, GFP_KERNEL);
1850                 if (!attrs->name) {
1851                         ret = -ENOMEM;
1852                         goto out;
1853                 }
1854         } else if (strncmp(str, "clock=", strlen("clock=")) == 0) {
1855                 strsep(&str, "=");
1856                 if (!str) {
1857                         ret = -EINVAL;
1858                         goto out;
1859                 }
1860
1861                 str = strstrip(str);
1862                 attrs->clock = kstrdup(str, GFP_KERNEL);
1863                 if (!attrs->clock) {
1864                         ret = -ENOMEM;
1865                         goto out;
1866                 }
1867         } else if (strncmp(str, "size=", strlen("size=")) == 0) {
1868                 int map_bits = parse_map_size(str);
1869
1870                 if (map_bits < 0) {
1871                         ret = map_bits;
1872                         goto out;
1873                 }
1874                 attrs->map_bits = map_bits;
1875         } else {
1876                 char *assignment;
1877
1878                 if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
1879                         hist_err("Too many variables defined: ", str);
1880                         ret = -EINVAL;
1881                         goto out;
1882                 }
1883
1884                 assignment = kstrdup(str, GFP_KERNEL);
1885                 if (!assignment) {
1886                         ret = -ENOMEM;
1887                         goto out;
1888                 }
1889
1890                 attrs->assignment_str[attrs->n_assignments++] = assignment;
1891         }
1892  out:
1893         return ret;
1894 }
1895
1896 static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
1897 {
1898         struct hist_trigger_attrs *attrs;
1899         int ret = 0;
1900
1901         attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
1902         if (!attrs)
1903                 return ERR_PTR(-ENOMEM);
1904
1905         while (trigger_str) {
1906                 char *str = strsep(&trigger_str, ":");
1907
1908                 if (strchr(str, '=')) {
1909                         ret = parse_assignment(str, attrs);
1910                         if (ret)
1911                                 goto free;
1912                 } else if (strcmp(str, "pause") == 0)
1913                         attrs->pause = true;
1914                 else if ((strcmp(str, "cont") == 0) ||
1915                          (strcmp(str, "continue") == 0))
1916                         attrs->cont = true;
1917                 else if (strcmp(str, "clear") == 0)
1918                         attrs->clear = true;
1919                 else {
1920                         ret = parse_action(str, attrs);
1921                         if (ret)
1922                                 goto free;
1923                 }
1924         }
1925
1926         if (!attrs->keys_str) {
1927                 ret = -EINVAL;
1928                 goto free;
1929         }
1930
1931         if (!attrs->clock) {
1932                 attrs->clock = kstrdup("global", GFP_KERNEL);
1933                 if (!attrs->clock) {
1934                         ret = -ENOMEM;
1935                         goto free;
1936                 }
1937         }
1938
1939         return attrs;
1940  free:
1941         destroy_hist_trigger_attrs(attrs);
1942
1943         return ERR_PTR(ret);
1944 }
1945
1946 static inline void save_comm(char *comm, struct task_struct *task)
1947 {
1948         if (!task->pid) {
1949                 strcpy(comm, "<idle>");
1950                 return;
1951         }
1952
1953         if (WARN_ON_ONCE(task->pid < 0)) {
1954                 strcpy(comm, "<XXX>");
1955                 return;
1956         }
1957
1958         memcpy(comm, task->comm, TASK_COMM_LEN);
1959 }
1960
1961 static void hist_elt_data_free(struct hist_elt_data *elt_data)
1962 {
1963         unsigned int i;
1964
1965         for (i = 0; i < SYNTH_FIELDS_MAX; i++)
1966                 kfree(elt_data->field_var_str[i]);
1967
1968         kfree(elt_data->comm);
1969         kfree(elt_data);
1970 }
1971
1972 static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
1973 {
1974         struct hist_elt_data *elt_data = elt->private_data;
1975
1976         hist_elt_data_free(elt_data);
1977 }
1978
1979 static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
1980 {
1981         struct hist_trigger_data *hist_data = elt->map->private_data;
1982         unsigned int size = TASK_COMM_LEN;
1983         struct hist_elt_data *elt_data;
1984         struct hist_field *key_field;
1985         unsigned int i, n_str;
1986
1987         elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
1988         if (!elt_data)
1989                 return -ENOMEM;
1990
1991         for_each_hist_key_field(i, hist_data) {
1992                 key_field = hist_data->fields[i];
1993
1994                 if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
1995                         elt_data->comm = kzalloc(size, GFP_KERNEL);
1996                         if (!elt_data->comm) {
1997                                 kfree(elt_data);
1998                                 return -ENOMEM;
1999                         }
2000                         break;
2001                 }
2002         }
2003
2004         n_str = hist_data->n_field_var_str + hist_data->n_max_var_str;
2005
2006         size = STR_VAR_LEN_MAX;
2007
2008         for (i = 0; i < n_str; i++) {
2009                 elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
2010                 if (!elt_data->field_var_str[i]) {
2011                         hist_elt_data_free(elt_data);
2012                         return -ENOMEM;
2013                 }
2014         }
2015
2016         elt->private_data = elt_data;
2017
2018         return 0;
2019 }
2020
2021 static void hist_trigger_elt_data_init(struct tracing_map_elt *elt)
2022 {
2023         struct hist_elt_data *elt_data = elt->private_data;
2024
2025         if (elt_data->comm)
2026                 save_comm(elt_data->comm, current);
2027 }
2028
2029 static const struct tracing_map_ops hist_trigger_elt_data_ops = {
2030         .elt_alloc      = hist_trigger_elt_data_alloc,
2031         .elt_free       = hist_trigger_elt_data_free,
2032         .elt_init       = hist_trigger_elt_data_init,
2033 };
2034
2035 static const char *get_hist_field_flags(struct hist_field *hist_field)
2036 {
2037         const char *flags_str = NULL;
2038
2039         if (hist_field->flags & HIST_FIELD_FL_HEX)
2040                 flags_str = "hex";
2041         else if (hist_field->flags & HIST_FIELD_FL_SYM)
2042                 flags_str = "sym";
2043         else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
2044                 flags_str = "sym-offset";
2045         else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
2046                 flags_str = "execname";
2047         else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
2048                 flags_str = "syscall";
2049         else if (hist_field->flags & HIST_FIELD_FL_LOG2)
2050                 flags_str = "log2";
2051         else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2052                 flags_str = "usecs";
2053
2054         return flags_str;
2055 }
2056
2057 static void expr_field_str(struct hist_field *field, char *expr)
2058 {
2059         if (field->flags & HIST_FIELD_FL_VAR_REF)
2060                 strcat(expr, "$");
2061
2062         strcat(expr, hist_field_name(field, 0));
2063
2064         if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) {
2065                 const char *flags_str = get_hist_field_flags(field);
2066
2067                 if (flags_str) {
2068                         strcat(expr, ".");
2069                         strcat(expr, flags_str);
2070                 }
2071         }
2072 }
2073
2074 static char *expr_str(struct hist_field *field, unsigned int level)
2075 {
2076         char *expr;
2077
2078         if (level > 1)
2079                 return NULL;
2080
2081         expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2082         if (!expr)
2083                 return NULL;
2084
2085         if (!field->operands[0]) {
2086                 expr_field_str(field, expr);
2087                 return expr;
2088         }
2089
2090         if (field->operator == FIELD_OP_UNARY_MINUS) {
2091                 char *subexpr;
2092
2093                 strcat(expr, "-(");
2094                 subexpr = expr_str(field->operands[0], ++level);
2095                 if (!subexpr) {
2096                         kfree(expr);
2097                         return NULL;
2098                 }
2099                 strcat(expr, subexpr);
2100                 strcat(expr, ")");
2101
2102                 kfree(subexpr);
2103
2104                 return expr;
2105         }
2106
2107         expr_field_str(field->operands[0], expr);
2108
2109         switch (field->operator) {
2110         case FIELD_OP_MINUS:
2111                 strcat(expr, "-");
2112                 break;
2113         case FIELD_OP_PLUS:
2114                 strcat(expr, "+");
2115                 break;
2116         default:
2117                 kfree(expr);
2118                 return NULL;
2119         }
2120
2121         expr_field_str(field->operands[1], expr);
2122
2123         return expr;
2124 }
2125
2126 static int contains_operator(char *str)
2127 {
2128         enum field_op_id field_op = FIELD_OP_NONE;
2129         char *op;
2130
2131         op = strpbrk(str, "+-");
2132         if (!op)
2133                 return FIELD_OP_NONE;
2134
2135         switch (*op) {
2136         case '-':
2137                 if (*str == '-')
2138                         field_op = FIELD_OP_UNARY_MINUS;
2139                 else
2140                         field_op = FIELD_OP_MINUS;
2141                 break;
2142         case '+':
2143                 field_op = FIELD_OP_PLUS;
2144                 break;
2145         default:
2146                 break;
2147         }
2148
2149         return field_op;
2150 }
2151
2152 static void destroy_hist_field(struct hist_field *hist_field,
2153                                unsigned int level)
2154 {
2155         unsigned int i;
2156
2157         if (level > 3)
2158                 return;
2159
2160         if (!hist_field)
2161                 return;
2162
2163         for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
2164                 destroy_hist_field(hist_field->operands[i], level + 1);
2165
2166         kfree(hist_field->var.name);
2167         kfree(hist_field->name);
2168         kfree(hist_field->type);
2169
2170         kfree(hist_field);
2171 }
2172
2173 static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
2174                                             struct ftrace_event_field *field,
2175                                             unsigned long flags,
2176                                             char *var_name)
2177 {
2178         struct hist_field *hist_field;
2179
2180         if (field && is_function_field(field))
2181                 return NULL;
2182
2183         hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
2184         if (!hist_field)
2185                 return NULL;
2186
2187         hist_field->hist_data = hist_data;
2188
2189         if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
2190                 goto out; /* caller will populate */
2191
2192         if (flags & HIST_FIELD_FL_VAR_REF) {
2193                 hist_field->fn = hist_field_var_ref;
2194                 goto out;
2195         }
2196
2197         if (flags & HIST_FIELD_FL_HITCOUNT) {
2198                 hist_field->fn = hist_field_counter;
2199                 hist_field->size = sizeof(u64);
2200                 hist_field->type = kstrdup("u64", GFP_KERNEL);
2201                 if (!hist_field->type)
2202                         goto free;
2203                 goto out;
2204         }
2205
2206         if (flags & HIST_FIELD_FL_STACKTRACE) {
2207                 hist_field->fn = hist_field_none;
2208                 goto out;
2209         }
2210
2211         if (flags & HIST_FIELD_FL_LOG2) {
2212                 unsigned long fl = flags & ~HIST_FIELD_FL_LOG2;
2213                 hist_field->fn = hist_field_log2;
2214                 hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
2215                 hist_field->size = hist_field->operands[0]->size;
2216                 hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL);
2217                 if (!hist_field->type)
2218                         goto free;
2219                 goto out;
2220         }
2221
2222         if (flags & HIST_FIELD_FL_TIMESTAMP) {
2223                 hist_field->fn = hist_field_timestamp;
2224                 hist_field->size = sizeof(u64);
2225                 hist_field->type = kstrdup("u64", GFP_KERNEL);
2226                 if (!hist_field->type)
2227                         goto free;
2228                 goto out;
2229         }
2230
2231         if (flags & HIST_FIELD_FL_CPU) {
2232                 hist_field->fn = hist_field_cpu;
2233                 hist_field->size = sizeof(int);
2234                 hist_field->type = kstrdup("unsigned int", GFP_KERNEL);
2235                 if (!hist_field->type)
2236                         goto free;
2237                 goto out;
2238         }
2239
2240         if (WARN_ON_ONCE(!field))
2241                 goto out;
2242
2243         if (is_string_field(field)) {
2244                 flags |= HIST_FIELD_FL_STRING;
2245
2246                 hist_field->size = MAX_FILTER_STR_VAL;
2247                 hist_field->type = kstrdup(field->type, GFP_KERNEL);
2248                 if (!hist_field->type)
2249                         goto free;
2250
2251                 if (field->filter_type == FILTER_STATIC_STRING)
2252                         hist_field->fn = hist_field_string;
2253                 else if (field->filter_type == FILTER_DYN_STRING)
2254                         hist_field->fn = hist_field_dynstring;
2255                 else
2256                         hist_field->fn = hist_field_pstring;
2257         } else {
2258                 hist_field->size = field->size;
2259                 hist_field->is_signed = field->is_signed;
2260                 hist_field->type = kstrdup(field->type, GFP_KERNEL);
2261                 if (!hist_field->type)
2262                         goto free;
2263
2264                 hist_field->fn = select_value_fn(field->size,
2265                                                  field->is_signed);
2266                 if (!hist_field->fn) {
2267                         destroy_hist_field(hist_field, 0);
2268                         return NULL;
2269                 }
2270         }
2271  out:
2272         hist_field->field = field;
2273         hist_field->flags = flags;
2274
2275         if (var_name) {
2276                 hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
2277                 if (!hist_field->var.name)
2278                         goto free;
2279         }
2280
2281         return hist_field;
2282  free:
2283         destroy_hist_field(hist_field, 0);
2284         return NULL;
2285 }
2286
2287 static void destroy_hist_fields(struct hist_trigger_data *hist_data)
2288 {
2289         unsigned int i;
2290
2291         for (i = 0; i < HIST_FIELDS_MAX; i++) {
2292                 if (hist_data->fields[i]) {
2293                         destroy_hist_field(hist_data->fields[i], 0);
2294                         hist_data->fields[i] = NULL;
2295                 }
2296         }
2297 }
2298
2299 static int init_var_ref(struct hist_field *ref_field,
2300                         struct hist_field *var_field,
2301                         char *system, char *event_name)
2302 {
2303         int err = 0;
2304
2305         ref_field->var.idx = var_field->var.idx;
2306         ref_field->var.hist_data = var_field->hist_data;
2307         ref_field->size = var_field->size;
2308         ref_field->is_signed = var_field->is_signed;
2309         ref_field->flags |= var_field->flags &
2310                 (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2311
2312         if (system) {
2313                 ref_field->system = kstrdup(system, GFP_KERNEL);
2314                 if (!ref_field->system)
2315                         return -ENOMEM;
2316         }
2317
2318         if (event_name) {
2319                 ref_field->event_name = kstrdup(event_name, GFP_KERNEL);
2320                 if (!ref_field->event_name) {
2321                         err = -ENOMEM;
2322                         goto free;
2323                 }
2324         }
2325
2326         if (var_field->var.name) {
2327                 ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
2328                 if (!ref_field->name) {
2329                         err = -ENOMEM;
2330                         goto free;
2331                 }
2332         } else if (var_field->name) {
2333                 ref_field->name = kstrdup(var_field->name, GFP_KERNEL);
2334                 if (!ref_field->name) {
2335                         err = -ENOMEM;
2336                         goto free;
2337                 }
2338         }
2339
2340         ref_field->type = kstrdup(var_field->type, GFP_KERNEL);
2341         if (!ref_field->type) {
2342                 err = -ENOMEM;
2343                 goto free;
2344         }
2345  out:
2346         return err;
2347  free:
2348         kfree(ref_field->system);
2349         kfree(ref_field->event_name);
2350         kfree(ref_field->name);
2351
2352         goto out;
2353 }
2354
2355 static struct hist_field *create_var_ref(struct hist_field *var_field,
2356                                          char *system, char *event_name)
2357 {
2358         unsigned long flags = HIST_FIELD_FL_VAR_REF;
2359         struct hist_field *ref_field;
2360
2361         ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
2362         if (ref_field) {
2363                 if (init_var_ref(ref_field, var_field, system, event_name)) {
2364                         destroy_hist_field(ref_field, 0);
2365                         return NULL;
2366                 }
2367         }
2368
2369         return ref_field;
2370 }
2371
2372 static bool is_var_ref(char *var_name)
2373 {
2374         if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
2375                 return false;
2376
2377         return true;
2378 }
2379
2380 static char *field_name_from_var(struct hist_trigger_data *hist_data,
2381                                  char *var_name)
2382 {
2383         char *name, *field;
2384         unsigned int i;
2385
2386         for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
2387                 name = hist_data->attrs->var_defs.name[i];
2388
2389                 if (strcmp(var_name, name) == 0) {
2390                         field = hist_data->attrs->var_defs.expr[i];
2391                         if (contains_operator(field) || is_var_ref(field))
2392                                 continue;
2393                         return field;
2394                 }
2395         }
2396
2397         return NULL;
2398 }
2399
2400 static char *local_field_var_ref(struct hist_trigger_data *hist_data,
2401                                  char *system, char *event_name,
2402                                  char *var_name)
2403 {
2404         struct trace_event_call *call;
2405
2406         if (system && event_name) {
2407                 call = hist_data->event_file->event_call;
2408
2409                 if (strcmp(system, call->class->system) != 0)
2410                         return NULL;
2411
2412                 if (strcmp(event_name, trace_event_name(call)) != 0)
2413                         return NULL;
2414         }
2415
2416         if (!!system != !!event_name)
2417                 return NULL;
2418
2419         if (!is_var_ref(var_name))
2420                 return NULL;
2421
2422         var_name++;
2423
2424         return field_name_from_var(hist_data, var_name);
2425 }
2426
2427 static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
2428                                         char *system, char *event_name,
2429                                         char *var_name)
2430 {
2431         struct hist_field *var_field = NULL, *ref_field = NULL;
2432
2433         if (!is_var_ref(var_name))
2434                 return NULL;
2435
2436         var_name++;
2437
2438         var_field = find_event_var(hist_data, system, event_name, var_name);
2439         if (var_field)
2440                 ref_field = create_var_ref(var_field, system, event_name);
2441
2442         if (!ref_field)
2443                 hist_err_event("Couldn't find variable: $",
2444                                system, event_name, var_name);
2445
2446         return ref_field;
2447 }
2448
2449 static struct ftrace_event_field *
2450 parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
2451             char *field_str, unsigned long *flags)
2452 {
2453         struct ftrace_event_field *field = NULL;
2454         char *field_name, *modifier, *str;
2455
2456         modifier = str = kstrdup(field_str, GFP_KERNEL);
2457         if (!modifier)
2458                 return ERR_PTR(-ENOMEM);
2459
2460         field_name = strsep(&modifier, ".");
2461         if (modifier) {
2462                 if (strcmp(modifier, "hex") == 0)
2463                         *flags |= HIST_FIELD_FL_HEX;
2464                 else if (strcmp(modifier, "sym") == 0)
2465                         *flags |= HIST_FIELD_FL_SYM;
2466                 else if (strcmp(modifier, "sym-offset") == 0)
2467                         *flags |= HIST_FIELD_FL_SYM_OFFSET;
2468                 else if ((strcmp(modifier, "execname") == 0) &&
2469                          (strcmp(field_name, "common_pid") == 0))
2470                         *flags |= HIST_FIELD_FL_EXECNAME;
2471                 else if (strcmp(modifier, "syscall") == 0)
2472                         *flags |= HIST_FIELD_FL_SYSCALL;
2473                 else if (strcmp(modifier, "log2") == 0)
2474                         *flags |= HIST_FIELD_FL_LOG2;
2475                 else if (strcmp(modifier, "usecs") == 0)
2476                         *flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
2477                 else {
2478                         hist_err("Invalid field modifier: ", modifier);
2479                         field = ERR_PTR(-EINVAL);
2480                         goto out;
2481                 }
2482         }
2483
2484         if (strcmp(field_name, "common_timestamp") == 0) {
2485                 *flags |= HIST_FIELD_FL_TIMESTAMP;
2486                 hist_data->enable_timestamps = true;
2487                 if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2488                         hist_data->attrs->ts_in_usecs = true;
2489         } else if (strcmp(field_name, "cpu") == 0)
2490                 *flags |= HIST_FIELD_FL_CPU;
2491         else {
2492                 field = trace_find_event_field(file->event_call, field_name);
2493                 if (!field || !field->size) {
2494                         hist_err("Couldn't find field: ", field_name);
2495                         field = ERR_PTR(-EINVAL);
2496                         goto out;
2497                 }
2498         }
2499  out:
2500         kfree(str);
2501
2502         return field;
2503 }
2504
2505 static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
2506                                        struct hist_field *var_ref,
2507                                        char *var_name)
2508 {
2509         struct hist_field *alias = NULL;
2510         unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;
2511
2512         alias = create_hist_field(hist_data, NULL, flags, var_name);
2513         if (!alias)
2514                 return NULL;
2515
2516         alias->fn = var_ref->fn;
2517         alias->operands[0] = var_ref;
2518
2519         if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
2520                 destroy_hist_field(alias, 0);
2521                 return NULL;
2522         }
2523
2524         return alias;
2525 }
2526
2527 static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
2528                                      struct trace_event_file *file, char *str,
2529                                      unsigned long *flags, char *var_name)
2530 {
2531         char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
2532         struct ftrace_event_field *field = NULL;
2533         struct hist_field *hist_field = NULL;
2534         int ret = 0;
2535
2536         s = strchr(str, '.');
2537         if (s) {
2538                 s = strchr(++s, '.');
2539                 if (s) {
2540                         ref_system = strsep(&str, ".");
2541                         if (!str) {
2542                                 ret = -EINVAL;
2543                                 goto out;
2544                         }
2545                         ref_event = strsep(&str, ".");
2546                         if (!str) {
2547                                 ret = -EINVAL;
2548                                 goto out;
2549                         }
2550                         ref_var = str;
2551                 }
2552         }
2553
2554         s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
2555         if (!s) {
2556                 hist_field = parse_var_ref(hist_data, ref_system, ref_event, ref_var);
2557                 if (hist_field) {
2558                         hist_data->var_refs[hist_data->n_var_refs] = hist_field;
2559                         hist_field->var_ref_idx = hist_data->n_var_refs++;
2560                         if (var_name) {
2561                                 hist_field = create_alias(hist_data, hist_field, var_name);
2562                                 if (!hist_field) {
2563                                         ret = -ENOMEM;
2564                                         goto out;
2565                                 }
2566                         }
2567                         return hist_field;
2568                 }
2569         } else
2570                 str = s;
2571
2572         field = parse_field(hist_data, file, str, flags);
2573         if (IS_ERR(field)) {
2574                 ret = PTR_ERR(field);
2575                 goto out;
2576         }
2577
2578         hist_field = create_hist_field(hist_data, field, *flags, var_name);
2579         if (!hist_field) {
2580                 ret = -ENOMEM;
2581                 goto out;
2582         }
2583
2584         return hist_field;
2585  out:
2586         return ERR_PTR(ret);
2587 }
2588
2589 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2590                                      struct trace_event_file *file,
2591                                      char *str, unsigned long flags,
2592                                      char *var_name, unsigned int level);
2593
2594 static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
2595                                       struct trace_event_file *file,
2596                                       char *str, unsigned long flags,
2597                                       char *var_name, unsigned int level)
2598 {
2599         struct hist_field *operand1, *expr = NULL;
2600         unsigned long operand_flags;
2601         int ret = 0;
2602         char *s;
2603
2604         /* we support only -(xxx) i.e. explicit parens required */
2605
2606         if (level > 3) {
2607                 hist_err("Too many subexpressions (3 max): ", str);
2608                 ret = -EINVAL;
2609                 goto free;
2610         }
2611
2612         str++; /* skip leading '-' */
2613
2614         s = strchr(str, '(');
2615         if (s)
2616                 str++;
2617         else {
2618                 ret = -EINVAL;
2619                 goto free;
2620         }
2621
2622         s = strrchr(str, ')');
2623         if (s)
2624                 *s = '\0';
2625         else {
2626                 ret = -EINVAL; /* no closing ')' */
2627                 goto free;
2628         }
2629
2630         flags |= HIST_FIELD_FL_EXPR;
2631         expr = create_hist_field(hist_data, NULL, flags, var_name);
2632         if (!expr) {
2633                 ret = -ENOMEM;
2634                 goto free;
2635         }
2636
2637         operand_flags = 0;
2638         operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
2639         if (IS_ERR(operand1)) {
2640                 ret = PTR_ERR(operand1);
2641                 goto free;
2642         }
2643
2644         expr->flags |= operand1->flags &
2645                 (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2646         expr->fn = hist_field_unary_minus;
2647         expr->operands[0] = operand1;
2648         expr->operator = FIELD_OP_UNARY_MINUS;
2649         expr->name = expr_str(expr, 0);
2650         expr->type = kstrdup(operand1->type, GFP_KERNEL);
2651         if (!expr->type) {
2652                 ret = -ENOMEM;
2653                 goto free;
2654         }
2655
2656         return expr;
2657  free:
2658         destroy_hist_field(expr, 0);
2659         return ERR_PTR(ret);
2660 }
2661
2662 static int check_expr_operands(struct hist_field *operand1,
2663                                struct hist_field *operand2)
2664 {
2665         unsigned long operand1_flags = operand1->flags;
2666         unsigned long operand2_flags = operand2->flags;
2667
2668         if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
2669             (operand1_flags & HIST_FIELD_FL_ALIAS)) {
2670                 struct hist_field *var;
2671
2672                 var = find_var_field(operand1->var.hist_data, operand1->name);
2673                 if (!var)
2674                         return -EINVAL;
2675                 operand1_flags = var->flags;
2676         }
2677
2678         if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
2679             (operand2_flags & HIST_FIELD_FL_ALIAS)) {
2680                 struct hist_field *var;
2681
2682                 var = find_var_field(operand2->var.hist_data, operand2->name);
2683                 if (!var)
2684                         return -EINVAL;
2685                 operand2_flags = var->flags;
2686         }
2687
2688         if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
2689             (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
2690                 hist_err("Timestamp units in expression don't match", NULL);
2691                 return -EINVAL;
2692         }
2693
2694         return 0;
2695 }
2696
2697 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2698                                      struct trace_event_file *file,
2699                                      char *str, unsigned long flags,
2700                                      char *var_name, unsigned int level)
2701 {
2702         struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
2703         unsigned long operand_flags;
2704         int field_op, ret = -EINVAL;
2705         char *sep, *operand1_str;
2706
2707         if (level > 3) {
2708                 hist_err("Too many subexpressions (3 max): ", str);
2709                 return ERR_PTR(-EINVAL);
2710         }
2711
2712         field_op = contains_operator(str);
2713
2714         if (field_op == FIELD_OP_NONE)
2715                 return parse_atom(hist_data, file, str, &flags, var_name);
2716
2717         if (field_op == FIELD_OP_UNARY_MINUS)
2718                 return parse_unary(hist_data, file, str, flags, var_name, ++level);
2719
2720         switch (field_op) {
2721         case FIELD_OP_MINUS:
2722                 sep = "-";
2723                 break;
2724         case FIELD_OP_PLUS:
2725                 sep = "+";
2726                 break;
2727         default:
2728                 goto free;
2729         }
2730
2731         operand1_str = strsep(&str, sep);
2732         if (!operand1_str || !str)
2733                 goto free;
2734
2735         operand_flags = 0;
2736         operand1 = parse_atom(hist_data, file, operand1_str,
2737                               &operand_flags, NULL);
2738         if (IS_ERR(operand1)) {
2739                 ret = PTR_ERR(operand1);
2740                 operand1 = NULL;
2741                 goto free;
2742         }
2743
2744         /* rest of string could be another expression e.g. b+c in a+b+c */
2745         operand_flags = 0;
2746         operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
2747         if (IS_ERR(operand2)) {
2748                 ret = PTR_ERR(operand2);
2749                 operand2 = NULL;
2750                 goto free;
2751         }
2752
2753         ret = check_expr_operands(operand1, operand2);
2754         if (ret)
2755                 goto free;
2756
2757         flags |= HIST_FIELD_FL_EXPR;
2758
2759         flags |= operand1->flags &
2760                 (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2761
2762         expr = create_hist_field(hist_data, NULL, flags, var_name);
2763         if (!expr) {
2764                 ret = -ENOMEM;
2765                 goto free;
2766         }
2767
2768         operand1->read_once = true;
2769         operand2->read_once = true;
2770
2771         expr->operands[0] = operand1;
2772         expr->operands[1] = operand2;
2773         expr->operator = field_op;
2774         expr->name = expr_str(expr, 0);
2775         expr->type = kstrdup(operand1->type, GFP_KERNEL);
2776         if (!expr->type) {
2777                 ret = -ENOMEM;
2778                 goto free;
2779         }
2780
2781         switch (field_op) {
2782         case FIELD_OP_MINUS:
2783                 expr->fn = hist_field_minus;
2784                 break;
2785         case FIELD_OP_PLUS:
2786                 expr->fn = hist_field_plus;
2787                 break;
2788         default:
2789                 ret = -EINVAL;
2790                 goto free;
2791         }
2792
2793         return expr;
2794  free:
2795         destroy_hist_field(operand1, 0);
2796         destroy_hist_field(operand2, 0);
2797         destroy_hist_field(expr, 0);
2798
2799         return ERR_PTR(ret);
2800 }
2801
2802 static char *find_trigger_filter(struct hist_trigger_data *hist_data,
2803                                  struct trace_event_file *file)
2804 {
2805         struct event_trigger_data *test;
2806
2807         list_for_each_entry_rcu(test, &file->triggers, list) {
2808                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2809                         if (test->private_data == hist_data)
2810                                 return test->filter_str;
2811                 }
2812         }
2813
2814         return NULL;
2815 }
2816
2817 static struct event_command trigger_hist_cmd;
2818 static int event_hist_trigger_func(struct event_command *cmd_ops,
2819                                    struct trace_event_file *file,
2820                                    char *glob, char *cmd, char *param);
2821
2822 static bool compatible_keys(struct hist_trigger_data *target_hist_data,
2823                             struct hist_trigger_data *hist_data,
2824                             unsigned int n_keys)
2825 {
2826         struct hist_field *target_hist_field, *hist_field;
2827         unsigned int n, i, j;
2828
2829         if (hist_data->n_fields - hist_data->n_vals != n_keys)
2830                 return false;
2831
2832         i = hist_data->n_vals;
2833         j = target_hist_data->n_vals;
2834
2835         for (n = 0; n < n_keys; n++) {
2836                 hist_field = hist_data->fields[i + n];
2837                 target_hist_field = target_hist_data->fields[j + n];
2838
2839                 if (strcmp(hist_field->type, target_hist_field->type) != 0)
2840                         return false;
2841                 if (hist_field->size != target_hist_field->size)
2842                         return false;
2843                 if (hist_field->is_signed != target_hist_field->is_signed)
2844                         return false;
2845         }
2846
2847         return true;
2848 }
2849
2850 static struct hist_trigger_data *
2851 find_compatible_hist(struct hist_trigger_data *target_hist_data,
2852                      struct trace_event_file *file)
2853 {
2854         struct hist_trigger_data *hist_data;
2855         struct event_trigger_data *test;
2856         unsigned int n_keys;
2857
2858         n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
2859
2860         list_for_each_entry_rcu(test, &file->triggers, list) {
2861                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2862                         hist_data = test->private_data;
2863
2864                         if (compatible_keys(target_hist_data, hist_data, n_keys))
2865                                 return hist_data;
2866                 }
2867         }
2868
2869         return NULL;
2870 }
2871
2872 static struct trace_event_file *event_file(struct trace_array *tr,
2873                                            char *system, char *event_name)
2874 {
2875         struct trace_event_file *file;
2876
2877         file = __find_event_file(tr, system, event_name);
2878         if (!file)
2879                 return ERR_PTR(-EINVAL);
2880
2881         return file;
2882 }
2883
2884 static struct hist_field *
2885 find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
2886                          char *system, char *event_name, char *field_name)
2887 {
2888         struct hist_field *event_var;
2889         char *synthetic_name;
2890
2891         synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2892         if (!synthetic_name)
2893                 return ERR_PTR(-ENOMEM);
2894
2895         strcpy(synthetic_name, "synthetic_");
2896         strcat(synthetic_name, field_name);
2897
2898         event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);
2899
2900         kfree(synthetic_name);
2901
2902         return event_var;
2903 }
2904
2905 /**
2906  * create_field_var_hist - Automatically create a histogram and var for a field
2907  * @target_hist_data: The target hist trigger
2908  * @subsys_name: Optional subsystem name
2909  * @event_name: Optional event name
2910  * @field_name: The name of the field (and the resulting variable)
2911  *
2912  * Hist trigger actions fetch data from variables, not directly from
2913  * events.  However, for convenience, users are allowed to directly
2914  * specify an event field in an action, which will be automatically
2915  * converted into a variable on their behalf.
2916
2917  * If a user specifies a field on an event that isn't the event the
2918  * histogram currently being defined (the target event histogram), the
2919  * only way that can be accomplished is if a new hist trigger is
2920  * created and the field variable defined on that.
2921  *
2922  * This function creates a new histogram compatible with the target
2923  * event (meaning a histogram with the same key as the target
2924  * histogram), and creates a variable for the specified field, but
2925  * with 'synthetic_' prepended to the variable name in order to avoid
2926  * collision with normal field variables.
2927  *
2928  * Return: The variable created for the field.
2929  */
2930 static struct hist_field *
2931 create_field_var_hist(struct hist_trigger_data *target_hist_data,
2932                       char *subsys_name, char *event_name, char *field_name)
2933 {
2934         struct trace_array *tr = target_hist_data->event_file->tr;
2935         struct hist_field *event_var = ERR_PTR(-EINVAL);
2936         struct hist_trigger_data *hist_data;
2937         unsigned int i, n, first = true;
2938         struct field_var_hist *var_hist;
2939         struct trace_event_file *file;
2940         struct hist_field *key_field;
2941         char *saved_filter;
2942         char *cmd;
2943         int ret;
2944
2945         if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
2946                 hist_err_event("onmatch: Too many field variables defined: ",
2947                                subsys_name, event_name, field_name);
2948                 return ERR_PTR(-EINVAL);
2949         }
2950
2951         file = event_file(tr, subsys_name, event_name);
2952
2953         if (IS_ERR(file)) {
2954                 hist_err_event("onmatch: Event file not found: ",
2955                                subsys_name, event_name, field_name);
2956                 ret = PTR_ERR(file);
2957                 return ERR_PTR(ret);
2958         }
2959
2960         /*
2961          * Look for a histogram compatible with target.  We'll use the
2962          * found histogram specification to create a new matching
2963          * histogram with our variable on it.  target_hist_data is not
2964          * yet a registered histogram so we can't use that.
2965          */
2966         hist_data = find_compatible_hist(target_hist_data, file);
2967         if (!hist_data) {
2968                 hist_err_event("onmatch: Matching event histogram not found: ",
2969                                subsys_name, event_name, field_name);
2970                 return ERR_PTR(-EINVAL);
2971         }
2972
2973         /* See if a synthetic field variable has already been created */
2974         event_var = find_synthetic_field_var(target_hist_data, subsys_name,
2975                                              event_name, field_name);
2976         if (!IS_ERR_OR_NULL(event_var))
2977                 return event_var;
2978
2979         var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
2980         if (!var_hist)
2981                 return ERR_PTR(-ENOMEM);
2982
2983         cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2984         if (!cmd) {
2985                 kfree(var_hist);
2986                 return ERR_PTR(-ENOMEM);
2987         }
2988
2989         /* Use the same keys as the compatible histogram */
2990         strcat(cmd, "keys=");
2991
2992         for_each_hist_key_field(i, hist_data) {
2993                 key_field = hist_data->fields[i];
2994                 if (!first)
2995                         strcat(cmd, ",");
2996                 strcat(cmd, key_field->field->name);
2997                 first = false;
2998         }
2999
3000         /* Create the synthetic field variable specification */
3001         strcat(cmd, ":synthetic_");
3002         strcat(cmd, field_name);
3003         strcat(cmd, "=");
3004         strcat(cmd, field_name);
3005
3006         /* Use the same filter as the compatible histogram */
3007         saved_filter = find_trigger_filter(hist_data, file);
3008         if (saved_filter) {
3009                 strcat(cmd, " if ");
3010                 strcat(cmd, saved_filter);
3011         }
3012
3013         var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
3014         if (!var_hist->cmd) {
3015                 kfree(cmd);
3016                 kfree(var_hist);
3017                 return ERR_PTR(-ENOMEM);
3018         }
3019
3020         /* Save the compatible histogram information */
3021         var_hist->hist_data = hist_data;
3022
3023         /* Create the new histogram with our variable */
3024         ret = event_hist_trigger_func(&trigger_hist_cmd, file,
3025                                       "", "hist", cmd);
3026         if (ret) {
3027                 kfree(cmd);
3028                 kfree(var_hist->cmd);
3029                 kfree(var_hist);
3030                 hist_err_event("onmatch: Couldn't create histogram for field: ",
3031                                subsys_name, event_name, field_name);
3032                 return ERR_PTR(ret);
3033         }
3034
3035         kfree(cmd);
3036
3037         /* If we can't find the variable, something went wrong */
3038         event_var = find_synthetic_field_var(target_hist_data, subsys_name,
3039                                              event_name, field_name);
3040         if (IS_ERR_OR_NULL(event_var)) {
3041                 kfree(var_hist->cmd);
3042                 kfree(var_hist);
3043                 hist_err_event("onmatch: Couldn't find synthetic variable: ",
3044                                subsys_name, event_name, field_name);
3045                 return ERR_PTR(-EINVAL);
3046         }
3047
3048         n = target_hist_data->n_field_var_hists;
3049         target_hist_data->field_var_hists[n] = var_hist;
3050         target_hist_data->n_field_var_hists++;
3051
3052         return event_var;
3053 }
3054
3055 static struct hist_field *
3056 find_target_event_var(struct hist_trigger_data *hist_data,
3057                       char *subsys_name, char *event_name, char *var_name)
3058 {
3059         struct trace_event_file *file = hist_data->event_file;
3060         struct hist_field *hist_field = NULL;
3061
3062         if (subsys_name) {
3063                 struct trace_event_call *call;
3064
3065                 if (!event_name)
3066                         return NULL;
3067
3068                 call = file->event_call;
3069
3070                 if (strcmp(subsys_name, call->class->system) != 0)
3071                         return NULL;
3072
3073                 if (strcmp(event_name, trace_event_name(call)) != 0)
3074                         return NULL;
3075         }
3076
3077         hist_field = find_var_field(hist_data, var_name);
3078
3079         return hist_field;
3080 }
3081
3082 static inline void __update_field_vars(struct tracing_map_elt *elt,
3083                                        struct ring_buffer_event *rbe,
3084                                        void *rec,
3085                                        struct field_var **field_vars,
3086                                        unsigned int n_field_vars,
3087                                        unsigned int field_var_str_start)
3088 {
3089         struct hist_elt_data *elt_data = elt->private_data;
3090         unsigned int i, j, var_idx;
3091         u64 var_val;
3092
3093         for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
3094                 struct field_var *field_var = field_vars[i];
3095                 struct hist_field *var = field_var->var;
3096                 struct hist_field *val = field_var->val;
3097
3098                 var_val = val->fn(val, elt, rbe, rec);
3099                 var_idx = var->var.idx;
3100
3101                 if (val->flags & HIST_FIELD_FL_STRING) {
3102                         char *str = elt_data->field_var_str[j++];
3103                         char *val_str = (char *)(uintptr_t)var_val;
3104
3105                         strscpy(str, val_str, STR_VAR_LEN_MAX);
3106                         var_val = (u64)(uintptr_t)str;
3107                 }
3108                 tracing_map_set_var(elt, var_idx, var_val);
3109         }
3110 }
3111
3112 static void update_field_vars(struct hist_trigger_data *hist_data,
3113                               struct tracing_map_elt *elt,
3114                               struct ring_buffer_event *rbe,
3115                               void *rec)
3116 {
3117         __update_field_vars(elt, rbe, rec, hist_data->field_vars,
3118                             hist_data->n_field_vars, 0);
3119 }
3120
3121 static void update_max_vars(struct hist_trigger_data *hist_data,
3122                             struct tracing_map_elt *elt,
3123                             struct ring_buffer_event *rbe,
3124                             void *rec)
3125 {
3126         __update_field_vars(elt, rbe, rec, hist_data->max_vars,
3127                             hist_data->n_max_vars, hist_data->n_field_var_str);
3128 }
3129
3130 static struct hist_field *create_var(struct hist_trigger_data *hist_data,
3131                                      struct trace_event_file *file,
3132                                      char *name, int size, const char *type)
3133 {
3134         struct hist_field *var;
3135         int idx;
3136
3137         if (find_var(hist_data, file, name) && !hist_data->remove) {
3138                 var = ERR_PTR(-EINVAL);
3139                 goto out;
3140         }
3141
3142         var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
3143         if (!var) {
3144                 var = ERR_PTR(-ENOMEM);
3145                 goto out;
3146         }
3147
3148         idx = tracing_map_add_var(hist_data->map);
3149         if (idx < 0) {
3150                 kfree(var);
3151                 var = ERR_PTR(-EINVAL);
3152                 goto out;
3153         }
3154
3155         var->flags = HIST_FIELD_FL_VAR;
3156         var->var.idx = idx;
3157         var->var.hist_data = var->hist_data = hist_data;
3158         var->size = size;
3159         var->var.name = kstrdup(name, GFP_KERNEL);
3160         var->type = kstrdup(type, GFP_KERNEL);
3161         if (!var->var.name || !var->type) {
3162                 kfree(var->var.name);
3163                 kfree(var->type);
3164                 kfree(var);
3165                 var = ERR_PTR(-ENOMEM);
3166         }
3167  out:
3168         return var;
3169 }
3170
3171 static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
3172                                           struct trace_event_file *file,
3173                                           char *field_name)
3174 {
3175         struct hist_field *val = NULL, *var = NULL;
3176         unsigned long flags = HIST_FIELD_FL_VAR;
3177         struct field_var *field_var;
3178         int ret = 0;
3179
3180         if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
3181                 hist_err("Too many field variables defined: ", field_name);
3182                 ret = -EINVAL;
3183                 goto err;
3184         }
3185
3186         val = parse_atom(hist_data, file, field_name, &flags, NULL);
3187         if (IS_ERR(val)) {
3188                 hist_err("Couldn't parse field variable: ", field_name);
3189                 ret = PTR_ERR(val);
3190                 goto err;
3191         }
3192
3193         var = create_var(hist_data, file, field_name, val->size, val->type);
3194         if (IS_ERR(var)) {
3195                 hist_err("Couldn't create or find variable: ", field_name);
3196                 kfree(val);
3197                 ret = PTR_ERR(var);
3198                 goto err;
3199         }
3200
3201         field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
3202         if (!field_var) {
3203                 kfree(val);
3204                 kfree(var);
3205                 ret =  -ENOMEM;
3206                 goto err;
3207         }
3208
3209         field_var->var = var;
3210         field_var->val = val;
3211  out:
3212         return field_var;
3213  err:
3214         field_var = ERR_PTR(ret);
3215         goto out;
3216 }
3217
3218 /**
3219  * create_target_field_var - Automatically create a variable for a field
3220  * @target_hist_data: The target hist trigger
3221  * @subsys_name: Optional subsystem name
3222  * @event_name: Optional event name
3223  * @var_name: The name of the field (and the resulting variable)
3224  *
3225  * Hist trigger actions fetch data from variables, not directly from
3226  * events.  However, for convenience, users are allowed to directly
3227  * specify an event field in an action, which will be automatically
3228  * converted into a variable on their behalf.
3229
3230  * This function creates a field variable with the name var_name on
3231  * the hist trigger currently being defined on the target event.  If
3232  * subsys_name and event_name are specified, this function simply
3233  * verifies that they do in fact match the target event subsystem and
3234  * event name.
3235  *
3236  * Return: The variable created for the field.
3237  */
3238 static struct field_var *
3239 create_target_field_var(struct hist_trigger_data *target_hist_data,
3240                         char *subsys_name, char *event_name, char *var_name)
3241 {
3242         struct trace_event_file *file = target_hist_data->event_file;
3243
3244         if (subsys_name) {
3245                 struct trace_event_call *call;
3246
3247                 if (!event_name)
3248                         return NULL;
3249
3250                 call = file->event_call;
3251
3252                 if (strcmp(subsys_name, call->class->system) != 0)
3253                         return NULL;
3254
3255                 if (strcmp(event_name, trace_event_name(call)) != 0)
3256                         return NULL;
3257         }
3258
3259         return create_field_var(target_hist_data, file, var_name);
3260 }
3261
3262 static void onmax_print(struct seq_file *m,
3263                         struct hist_trigger_data *hist_data,
3264                         struct tracing_map_elt *elt,
3265                         struct action_data *data)
3266 {
3267         unsigned int i, save_var_idx, max_idx = data->onmax.max_var->var.idx;
3268
3269         seq_printf(m, "\n\tmax: %10llu", tracing_map_read_var(elt, max_idx));
3270
3271         for (i = 0; i < hist_data->n_max_vars; i++) {
3272                 struct hist_field *save_val = hist_data->max_vars[i]->val;
3273                 struct hist_field *save_var = hist_data->max_vars[i]->var;
3274                 u64 val;
3275
3276                 save_var_idx = save_var->var.idx;
3277
3278                 val = tracing_map_read_var(elt, save_var_idx);
3279
3280                 if (save_val->flags & HIST_FIELD_FL_STRING) {
3281                         seq_printf(m, "  %s: %-32s", save_var->var.name,
3282                                    (char *)(uintptr_t)(val));
3283                 } else
3284                         seq_printf(m, "  %s: %10llu", save_var->var.name, val);
3285         }
3286 }
3287
3288 static void onmax_save(struct hist_trigger_data *hist_data,
3289                        struct tracing_map_elt *elt, void *rec,
3290                        struct ring_buffer_event *rbe,
3291                        struct action_data *data, u64 *var_ref_vals)
3292 {
3293         unsigned int max_idx = data->onmax.max_var->var.idx;
3294         unsigned int max_var_ref_idx = data->onmax.max_var_ref_idx;
3295
3296         u64 var_val, max_val;
3297
3298         var_val = var_ref_vals[max_var_ref_idx];
3299         max_val = tracing_map_read_var(elt, max_idx);
3300
3301         if (var_val <= max_val)
3302                 return;
3303
3304         tracing_map_set_var(elt, max_idx, var_val);
3305
3306         update_max_vars(hist_data, elt, rbe, rec);
3307 }
3308
3309 static void onmax_destroy(struct action_data *data)
3310 {
3311         unsigned int i;
3312
3313         destroy_hist_field(data->onmax.max_var, 0);
3314         destroy_hist_field(data->onmax.var, 0);
3315
3316         kfree(data->onmax.var_str);
3317         kfree(data->onmax.fn_name);
3318
3319         for (i = 0; i < data->n_params; i++)
3320                 kfree(data->params[i]);
3321
3322         kfree(data);
3323 }
3324
3325 static int onmax_create(struct hist_trigger_data *hist_data,
3326                         struct action_data *data)
3327 {
3328         struct trace_event_file *file = hist_data->event_file;
3329         struct hist_field *var_field, *ref_field, *max_var;
3330         unsigned int var_ref_idx = hist_data->n_var_refs;
3331         struct field_var *field_var;
3332         char *onmax_var_str, *param;
3333         unsigned long flags;
3334         unsigned int i;
3335         int ret = 0;
3336
3337         onmax_var_str = data->onmax.var_str;
3338         if (onmax_var_str[0] != '$') {
3339                 hist_err("onmax: For onmax(x), x must be a variable: ", onmax_var_str);
3340                 return -EINVAL;
3341         }
3342         onmax_var_str++;
3343
3344         var_field = find_target_event_var(hist_data, NULL, NULL, onmax_var_str);
3345         if (!var_field) {
3346                 hist_err("onmax: Couldn't find onmax variable: ", onmax_var_str);
3347                 return -EINVAL;
3348         }
3349
3350         flags = HIST_FIELD_FL_VAR_REF;
3351         ref_field = create_hist_field(hist_data, NULL, flags, NULL);
3352         if (!ref_field)
3353                 return -ENOMEM;
3354
3355         if (init_var_ref(ref_field, var_field, NULL, NULL)) {
3356                 destroy_hist_field(ref_field, 0);
3357                 ret = -ENOMEM;
3358                 goto out;
3359         }
3360         hist_data->var_refs[hist_data->n_var_refs] = ref_field;
3361         ref_field->var_ref_idx = hist_data->n_var_refs++;
3362         data->onmax.var = ref_field;
3363
3364         data->fn = onmax_save;
3365         data->onmax.max_var_ref_idx = var_ref_idx;
3366         max_var = create_var(hist_data, file, "max", sizeof(u64), "u64");
3367         if (IS_ERR(max_var)) {
3368                 hist_err("onmax: Couldn't create onmax variable: ", "max");
3369                 ret = PTR_ERR(max_var);
3370                 goto out;
3371         }
3372         data->onmax.max_var = max_var;
3373
3374         for (i = 0; i < data->n_params; i++) {
3375                 param = kstrdup(data->params[i], GFP_KERNEL);
3376                 if (!param) {
3377                         ret = -ENOMEM;
3378                         goto out;
3379                 }
3380
3381                 field_var = create_target_field_var(hist_data, NULL, NULL, param);
3382                 if (IS_ERR(field_var)) {
3383                         hist_err("onmax: Couldn't create field variable: ", param);
3384                         ret = PTR_ERR(field_var);
3385                         kfree(param);
3386                         goto out;
3387                 }
3388
3389                 hist_data->max_vars[hist_data->n_max_vars++] = field_var;
3390                 if (field_var->val->flags & HIST_FIELD_FL_STRING)
3391                         hist_data->n_max_var_str++;
3392
3393                 kfree(param);
3394         }
3395  out:
3396         return ret;
3397 }
3398
3399 static int parse_action_params(char *params, struct action_data *data)
3400 {
3401         char *param, *saved_param;
3402         int ret = 0;
3403
3404         while (params) {
3405                 if (data->n_params >= SYNTH_FIELDS_MAX)
3406                         goto out;
3407
3408                 param = strsep(&params, ",");
3409                 if (!param) {
3410                         ret = -EINVAL;
3411                         goto out;
3412                 }
3413
3414                 param = strstrip(param);
3415                 if (strlen(param) < 2) {
3416                         hist_err("Invalid action param: ", param);
3417                         ret = -EINVAL;
3418                         goto out;
3419                 }
3420
3421                 saved_param = kstrdup(param, GFP_KERNEL);
3422                 if (!saved_param) {
3423                         ret = -ENOMEM;
3424                         goto out;
3425                 }
3426
3427                 data->params[data->n_params++] = saved_param;
3428         }
3429  out:
3430         return ret;
3431 }
3432
3433 static struct action_data *onmax_parse(char *str)
3434 {
3435         char *onmax_fn_name, *onmax_var_str;
3436         struct action_data *data;
3437         int ret = -EINVAL;
3438
3439         data = kzalloc(sizeof(*data), GFP_KERNEL);
3440         if (!data)
3441                 return ERR_PTR(-ENOMEM);
3442
3443         onmax_var_str = strsep(&str, ")");
3444         if (!onmax_var_str || !str) {
3445                 ret = -EINVAL;
3446                 goto free;
3447         }
3448
3449         data->onmax.var_str = kstrdup(onmax_var_str, GFP_KERNEL);
3450         if (!data->onmax.var_str) {
3451                 ret = -ENOMEM;
3452                 goto free;
3453         }
3454
3455         strsep(&str, ".");
3456         if (!str)
3457                 goto free;
3458
3459         onmax_fn_name = strsep(&str, "(");
3460         if (!onmax_fn_name || !str)
3461                 goto free;
3462
3463         if (strncmp(onmax_fn_name, "save", strlen("save")) == 0) {
3464                 char *params = strsep(&str, ")");
3465
3466                 if (!params) {
3467                         ret = -EINVAL;
3468                         goto free;
3469                 }
3470
3471                 ret = parse_action_params(params, data);
3472                 if (ret)
3473                         goto free;
3474         } else
3475                 goto free;
3476
3477         data->onmax.fn_name = kstrdup(onmax_fn_name, GFP_KERNEL);
3478         if (!data->onmax.fn_name) {
3479                 ret = -ENOMEM;
3480                 goto free;
3481         }
3482  out:
3483         return data;
3484  free:
3485         onmax_destroy(data);
3486         data = ERR_PTR(ret);
3487         goto out;
3488 }
3489
3490 static void onmatch_destroy(struct action_data *data)
3491 {
3492         unsigned int i;
3493
3494         mutex_lock(&synth_event_mutex);
3495
3496         kfree(data->onmatch.match_event);
3497         kfree(data->onmatch.match_event_system);
3498         kfree(data->onmatch.synth_event_name);
3499
3500         for (i = 0; i < data->n_params; i++)
3501                 kfree(data->params[i]);
3502
3503         if (data->onmatch.synth_event)
3504                 data->onmatch.synth_event->ref--;
3505
3506         kfree(data);
3507
3508         mutex_unlock(&synth_event_mutex);
3509 }
3510
3511 static void destroy_field_var(struct field_var *field_var)
3512 {
3513         if (!field_var)
3514                 return;
3515
3516         destroy_hist_field(field_var->var, 0);
3517         destroy_hist_field(field_var->val, 0);
3518
3519         kfree(field_var);
3520 }
3521
3522 static void destroy_field_vars(struct hist_trigger_data *hist_data)
3523 {
3524         unsigned int i;
3525
3526         for (i = 0; i < hist_data->n_field_vars; i++)
3527                 destroy_field_var(hist_data->field_vars[i]);
3528 }
3529
3530 static void save_field_var(struct hist_trigger_data *hist_data,
3531                            struct field_var *field_var)
3532 {
3533         hist_data->field_vars[hist_data->n_field_vars++] = field_var;
3534
3535         if (field_var->val->flags & HIST_FIELD_FL_STRING)
3536                 hist_data->n_field_var_str++;
3537 }
3538
3539
3540 static void destroy_synth_var_refs(struct hist_trigger_data *hist_data)
3541 {
3542         unsigned int i;
3543
3544         for (i = 0; i < hist_data->n_synth_var_refs; i++)
3545                 destroy_hist_field(hist_data->synth_var_refs[i], 0);
3546 }
3547
3548 static void save_synth_var_ref(struct hist_trigger_data *hist_data,
3549                          struct hist_field *var_ref)
3550 {
3551         hist_data->synth_var_refs[hist_data->n_synth_var_refs++] = var_ref;
3552
3553         hist_data->var_refs[hist_data->n_var_refs] = var_ref;
3554         var_ref->var_ref_idx = hist_data->n_var_refs++;
3555 }
3556
3557 static int check_synth_field(struct synth_event *event,
3558                              struct hist_field *hist_field,
3559                              unsigned int field_pos)
3560 {
3561         struct synth_field *field;
3562
3563         if (field_pos >= event->n_fields)
3564                 return -EINVAL;
3565
3566         field = event->fields[field_pos];
3567
3568         if (strcmp(field->type, hist_field->type) != 0)
3569                 return -EINVAL;
3570
3571         return 0;
3572 }
3573
3574 static struct hist_field *
3575 onmatch_find_var(struct hist_trigger_data *hist_data, struct action_data *data,
3576                  char *system, char *event, char *var)
3577 {
3578         struct hist_field *hist_field;
3579
3580         var++; /* skip '$' */
3581
3582         hist_field = find_target_event_var(hist_data, system, event, var);
3583         if (!hist_field) {
3584                 if (!system) {
3585                         system = data->onmatch.match_event_system;
3586                         event = data->onmatch.match_event;
3587                 }
3588
3589                 hist_field = find_event_var(hist_data, system, event, var);
3590         }
3591
3592         if (!hist_field)
3593                 hist_err_event("onmatch: Couldn't find onmatch param: $", system, event, var);
3594
3595         return hist_field;
3596 }
3597
3598 static struct hist_field *
3599 onmatch_create_field_var(struct hist_trigger_data *hist_data,
3600                          struct action_data *data, char *system,
3601                          char *event, char *var)
3602 {
3603         struct hist_field *hist_field = NULL;
3604         struct field_var *field_var;
3605
3606         /*
3607          * First try to create a field var on the target event (the
3608          * currently being defined).  This will create a variable for
3609          * unqualified fields on the target event, or if qualified,
3610          * target fields that have qualified names matching the target.
3611          */
3612         field_var = create_target_field_var(hist_data, system, event, var);
3613
3614         if (field_var && !IS_ERR(field_var)) {
3615                 save_field_var(hist_data, field_var);
3616                 hist_field = field_var->var;
3617         } else {
3618                 field_var = NULL;
3619                 /*
3620                  * If no explicit system.event is specfied, default to
3621                  * looking for fields on the onmatch(system.event.xxx)
3622                  * event.
3623                  */
3624                 if (!system) {
3625                         system = data->onmatch.match_event_system;
3626                         event = data->onmatch.match_event;
3627                 }
3628
3629                 /*
3630                  * At this point, we're looking at a field on another
3631                  * event.  Because we can't modify a hist trigger on
3632                  * another event to add a variable for a field, we need
3633                  * to create a new trigger on that event and create the
3634                  * variable at the same time.
3635                  */
3636                 hist_field = create_field_var_hist(hist_data, system, event, var);
3637                 if (IS_ERR(hist_field))
3638                         goto free;
3639         }
3640  out:
3641         return hist_field;
3642  free:
3643         destroy_field_var(field_var);
3644         hist_field = NULL;
3645         goto out;
3646 }
3647
3648 static int onmatch_create(struct hist_trigger_data *hist_data,
3649                           struct trace_event_file *file,
3650                           struct action_data *data)
3651 {
3652         char *event_name, *param, *system = NULL;
3653         struct hist_field *hist_field, *var_ref;
3654         unsigned int i, var_ref_idx;
3655         unsigned int field_pos = 0;
3656         struct synth_event *event;
3657         int ret = 0;
3658
3659         mutex_lock(&synth_event_mutex);
3660         event = find_synth_event(data->onmatch.synth_event_name);
3661         if (!event) {
3662                 hist_err("onmatch: Couldn't find synthetic event: ", data->onmatch.synth_event_name);
3663                 mutex_unlock(&synth_event_mutex);
3664                 return -EINVAL;
3665         }
3666         event->ref++;
3667         mutex_unlock(&synth_event_mutex);
3668
3669         var_ref_idx = hist_data->n_var_refs;
3670
3671         for (i = 0; i < data->n_params; i++) {
3672                 char *p;
3673
3674                 p = param = kstrdup(data->params[i], GFP_KERNEL);
3675                 if (!param) {
3676                         ret = -ENOMEM;
3677                         goto err;
3678                 }
3679
3680                 system = strsep(&param, ".");
3681                 if (!param) {
3682                         param = (char *)system;
3683                         system = event_name = NULL;
3684                 } else {
3685                         event_name = strsep(&param, ".");
3686                         if (!param) {
3687                                 kfree(p);
3688                                 ret = -EINVAL;
3689                                 goto err;
3690                         }
3691                 }
3692
3693                 if (param[0] == '$')
3694                         hist_field = onmatch_find_var(hist_data, data, system,
3695                                                       event_name, param);
3696                 else
3697                         hist_field = onmatch_create_field_var(hist_data, data,
3698                                                               system,
3699                                                               event_name,
3700                                                               param);
3701
3702                 if (!hist_field) {
3703                         kfree(p);
3704                         ret = -EINVAL;
3705                         goto err;
3706                 }
3707
3708                 if (check_synth_field(event, hist_field, field_pos) == 0) {
3709                         var_ref = create_var_ref(hist_field, system, event_name);
3710                         if (!var_ref) {
3711                                 kfree(p);
3712                                 ret = -ENOMEM;
3713                                 goto err;
3714                         }
3715
3716                         save_synth_var_ref(hist_data, var_ref);
3717                         field_pos++;
3718                         kfree(p);
3719                         continue;
3720                 }
3721
3722                 hist_err_event("onmatch: Param type doesn't match synthetic event field type: ",
3723                                system, event_name, param);
3724                 kfree(p);
3725                 ret = -EINVAL;
3726                 goto err;
3727         }
3728
3729         if (field_pos != event->n_fields) {
3730                 hist_err("onmatch: Param count doesn't match synthetic event field count: ", event->name);
3731                 ret = -EINVAL;
3732                 goto err;
3733         }
3734
3735         data->fn = action_trace;
3736         data->onmatch.synth_event = event;
3737         data->onmatch.var_ref_idx = var_ref_idx;
3738  out:
3739         return ret;
3740  err:
3741         mutex_lock(&synth_event_mutex);
3742         event->ref--;
3743         mutex_unlock(&synth_event_mutex);
3744
3745         goto out;
3746 }
3747
3748 static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
3749 {
3750         char *match_event, *match_event_system;
3751         char *synth_event_name, *params;
3752         struct action_data *data;
3753         int ret = -EINVAL;
3754
3755         data = kzalloc(sizeof(*data), GFP_KERNEL);
3756         if (!data)
3757                 return ERR_PTR(-ENOMEM);
3758
3759         match_event = strsep(&str, ")");
3760         if (!match_event || !str) {
3761                 hist_err("onmatch: Missing closing paren: ", match_event);
3762                 goto free;
3763         }
3764
3765         match_event_system = strsep(&match_event, ".");
3766         if (!match_event) {
3767                 hist_err("onmatch: Missing subsystem for match event: ", match_event_system);
3768                 goto free;
3769         }
3770
3771         if (IS_ERR(event_file(tr, match_event_system, match_event))) {
3772                 hist_err_event("onmatch: Invalid subsystem or event name: ",
3773                                match_event_system, match_event, NULL);
3774                 goto free;
3775         }
3776
3777         data->onmatch.match_event = kstrdup(match_event, GFP_KERNEL);
3778         if (!data->onmatch.match_event) {
3779                 ret = -ENOMEM;
3780                 goto free;
3781         }
3782
3783         data->onmatch.match_event_system = kstrdup(match_event_system, GFP_KERNEL);
3784         if (!data->onmatch.match_event_system) {
3785                 ret = -ENOMEM;
3786                 goto free;
3787         }
3788
3789         strsep(&str, ".");
3790         if (!str) {
3791                 hist_err("onmatch: Missing . after onmatch(): ", str);
3792                 goto free;
3793         }
3794
3795         synth_event_name = strsep(&str, "(");
3796         if (!synth_event_name || !str) {
3797                 hist_err("onmatch: Missing opening paramlist paren: ", synth_event_name);
3798                 goto free;
3799         }
3800
3801         data->onmatch.synth_event_name = kstrdup(synth_event_name, GFP_KERNEL);
3802         if (!data->onmatch.synth_event_name) {
3803                 ret = -ENOMEM;
3804                 goto free;
3805         }
3806
3807         params = strsep(&str, ")");
3808         if (!params || !str || (str && strlen(str))) {
3809                 hist_err("onmatch: Missing closing paramlist paren: ", params);
3810                 goto free;
3811         }
3812
3813         ret = parse_action_params(params, data);
3814         if (ret)
3815                 goto free;
3816  out:
3817         return data;
3818  free:
3819         onmatch_destroy(data);
3820         data = ERR_PTR(ret);
3821         goto out;
3822 }
3823
3824 static int create_hitcount_val(struct hist_trigger_data *hist_data)
3825 {
3826         hist_data->fields[HITCOUNT_IDX] =
3827                 create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
3828         if (!hist_data->fields[HITCOUNT_IDX])
3829                 return -ENOMEM;
3830
3831         hist_data->n_vals++;
3832         hist_data->n_fields++;
3833
3834         if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
3835                 return -EINVAL;
3836
3837         return 0;
3838 }
3839
3840 static int __create_val_field(struct hist_trigger_data *hist_data,
3841                               unsigned int val_idx,
3842                               struct trace_event_file *file,
3843                               char *var_name, char *field_str,
3844                               unsigned long flags)
3845 {
3846         struct hist_field *hist_field;
3847         int ret = 0;
3848
3849         hist_field = parse_expr(hist_data, file, field_str, flags, var_name, 0);
3850         if (IS_ERR(hist_field)) {
3851                 ret = PTR_ERR(hist_field);
3852                 goto out;
3853         }
3854
3855         hist_data->fields[val_idx] = hist_field;
3856
3857         ++hist_data->n_vals;
3858         ++hist_data->n_fields;
3859
3860         if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
3861                 ret = -EINVAL;
3862  out:
3863         return ret;
3864 }
3865
3866 static int create_val_field(struct hist_trigger_data *hist_data,
3867                             unsigned int val_idx,
3868                             struct trace_event_file *file,
3869                             char *field_str)
3870 {
3871         if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
3872                 return -EINVAL;
3873
3874         return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
3875 }
3876
3877 static int create_var_field(struct hist_trigger_data *hist_data,
3878                             unsigned int val_idx,
3879                             struct trace_event_file *file,
3880                             char *var_name, char *expr_str)
3881 {
3882         unsigned long flags = 0;
3883
3884         if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
3885                 return -EINVAL;
3886
3887         if (find_var(hist_data, file, var_name) && !hist_data->remove) {
3888                 hist_err("Variable already defined: ", var_name);
3889                 return -EINVAL;
3890         }
3891
3892         flags |= HIST_FIELD_FL_VAR;
3893         hist_data->n_vars++;
3894         if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
3895                 return -EINVAL;
3896
3897         return __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
3898 }
3899
3900 static int create_val_fields(struct hist_trigger_data *hist_data,
3901                              struct trace_event_file *file)
3902 {
3903         char *fields_str, *field_str;
3904         unsigned int i, j = 1;
3905         int ret;
3906
3907         ret = create_hitcount_val(hist_data);
3908         if (ret)
3909                 goto out;
3910
3911         fields_str = hist_data->attrs->vals_str;
3912         if (!fields_str)
3913                 goto out;
3914
3915         strsep(&fields_str, "=");
3916         if (!fields_str)
3917                 goto out;
3918
3919         for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
3920                      j < TRACING_MAP_VALS_MAX; i++) {
3921                 field_str = strsep(&fields_str, ",");
3922                 if (!field_str)
3923                         break;
3924
3925                 if (strcmp(field_str, "hitcount") == 0)
3926                         continue;
3927
3928                 ret = create_val_field(hist_data, j++, file, field_str);
3929                 if (ret)
3930                         goto out;
3931         }
3932
3933         if (fields_str && (strcmp(fields_str, "hitcount") != 0))
3934                 ret = -EINVAL;
3935  out:
3936         return ret;
3937 }
3938
3939 static int create_key_field(struct hist_trigger_data *hist_data,
3940                             unsigned int key_idx,
3941                             unsigned int key_offset,
3942                             struct trace_event_file *file,
3943                             char *field_str)
3944 {
3945         struct hist_field *hist_field = NULL;
3946
3947         unsigned long flags = 0;
3948         unsigned int key_size;
3949         int ret = 0;
3950
3951         if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
3952                 return -EINVAL;
3953
3954         flags |= HIST_FIELD_FL_KEY;
3955
3956         if (strcmp(field_str, "stacktrace") == 0) {
3957                 flags |= HIST_FIELD_FL_STACKTRACE;
3958                 key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
3959                 hist_field = create_hist_field(hist_data, NULL, flags, NULL);
3960         } else {
3961                 hist_field = parse_expr(hist_data, file, field_str, flags,
3962                                         NULL, 0);
3963                 if (IS_ERR(hist_field)) {
3964                         ret = PTR_ERR(hist_field);
3965                         goto out;
3966                 }
3967
3968                 if (hist_field->flags & HIST_FIELD_FL_VAR_REF) {
3969                         hist_err("Using variable references as keys not supported: ", field_str);
3970                         destroy_hist_field(hist_field, 0);
3971                         ret = -EINVAL;
3972                         goto out;
3973                 }
3974
3975                 key_size = hist_field->size;
3976         }
3977
3978         hist_data->fields[key_idx] = hist_field;
3979
3980         key_size = ALIGN(key_size, sizeof(u64));
3981         hist_data->fields[key_idx]->size = key_size;
3982         hist_data->fields[key_idx]->offset = key_offset;
3983
3984         hist_data->key_size += key_size;
3985
3986         if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
3987                 ret = -EINVAL;
3988                 goto out;
3989         }
3990
3991         hist_data->n_keys++;
3992         hist_data->n_fields++;
3993
3994         if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
3995                 return -EINVAL;
3996
3997         ret = key_size;
3998  out:
3999         return ret;
4000 }
4001
4002 static int create_key_fields(struct hist_trigger_data *hist_data,
4003                              struct trace_event_file *file)
4004 {
4005         unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
4006         char *fields_str, *field_str;
4007         int ret = -EINVAL;
4008
4009         fields_str = hist_data->attrs->keys_str;
4010         if (!fields_str)
4011                 goto out;
4012
4013         strsep(&fields_str, "=");
4014         if (!fields_str)
4015                 goto out;
4016
4017         for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
4018                 field_str = strsep(&fields_str, ",");
4019                 if (!field_str)
4020                         break;
4021                 ret = create_key_field(hist_data, i, key_offset,
4022                                        file, field_str);
4023                 if (ret < 0)
4024                         goto out;
4025                 key_offset += ret;
4026         }
4027         if (fields_str) {
4028                 ret = -EINVAL;
4029                 goto out;
4030         }
4031         ret = 0;
4032  out:
4033         return ret;
4034 }
4035
4036 static int create_var_fields(struct hist_trigger_data *hist_data,
4037                              struct trace_event_file *file)
4038 {
4039         unsigned int i, j = hist_data->n_vals;
4040         int ret = 0;
4041
4042         unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
4043
4044         for (i = 0; i < n_vars; i++) {
4045                 char *var_name = hist_data->attrs->var_defs.name[i];
4046                 char *expr = hist_data->attrs->var_defs.expr[i];
4047
4048                 ret = create_var_field(hist_data, j++, file, var_name, expr);
4049                 if (ret)
4050                         goto out;
4051         }
4052  out:
4053         return ret;
4054 }
4055
4056 static void free_var_defs(struct hist_trigger_data *hist_data)
4057 {
4058         unsigned int i;
4059
4060         for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
4061                 kfree(hist_data->attrs->var_defs.name[i]);
4062                 kfree(hist_data->attrs->var_defs.expr[i]);
4063         }
4064
4065         hist_data->attrs->var_defs.n_vars = 0;
4066 }
4067
4068 static int parse_var_defs(struct hist_trigger_data *hist_data)
4069 {
4070         char *s, *str, *var_name, *field_str;
4071         unsigned int i, j, n_vars = 0;
4072         int ret = 0;
4073
4074         for (i = 0; i < hist_data->attrs->n_assignments; i++) {
4075                 str = hist_data->attrs->assignment_str[i];
4076                 for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
4077                         field_str = strsep(&str, ",");
4078                         if (!field_str)
4079                                 break;
4080
4081                         var_name = strsep(&field_str, "=");
4082                         if (!var_name || !field_str) {
4083                                 hist_err("Malformed assignment: ", var_name);
4084                                 ret = -EINVAL;
4085                                 goto free;
4086                         }
4087
4088                         if (n_vars == TRACING_MAP_VARS_MAX) {
4089                                 hist_err("Too many variables defined: ", var_name);
4090                                 ret = -EINVAL;
4091                                 goto free;
4092                         }
4093
4094                         s = kstrdup(var_name, GFP_KERNEL);
4095                         if (!s) {
4096                                 ret = -ENOMEM;
4097                                 goto free;
4098                         }
4099                         hist_data->attrs->var_defs.name[n_vars] = s;
4100
4101                         s = kstrdup(field_str, GFP_KERNEL);
4102                         if (!s) {
4103                                 kfree(hist_data->attrs->var_defs.name[n_vars]);
4104                                 ret = -ENOMEM;
4105                                 goto free;
4106                         }
4107                         hist_data->attrs->var_defs.expr[n_vars++] = s;
4108
4109                         hist_data->attrs->var_defs.n_vars = n_vars;
4110                 }
4111         }
4112
4113         return ret;
4114  free:
4115         free_var_defs(hist_data);
4116
4117         return ret;
4118 }
4119
4120 static int create_hist_fields(struct hist_trigger_data *hist_data,
4121                               struct trace_event_file *file)
4122 {
4123         int ret;
4124
4125         ret = parse_var_defs(hist_data);
4126         if (ret)
4127                 goto out;
4128
4129         ret = create_val_fields(hist_data, file);
4130         if (ret)
4131                 goto out;
4132
4133         ret = create_var_fields(hist_data, file);
4134         if (ret)
4135                 goto out;
4136
4137         ret = create_key_fields(hist_data, file);
4138         if (ret)
4139                 goto out;
4140  out:
4141         free_var_defs(hist_data);
4142
4143         return ret;
4144 }
4145
4146 static int is_descending(const char *str)
4147 {
4148         if (!str)
4149                 return 0;
4150
4151         if (strcmp(str, "descending") == 0)
4152                 return 1;
4153
4154         if (strcmp(str, "ascending") == 0)
4155                 return 0;
4156
4157         return -EINVAL;
4158 }
4159
4160 static int create_sort_keys(struct hist_trigger_data *hist_data)
4161 {
4162         char *fields_str = hist_data->attrs->sort_key_str;
4163         struct tracing_map_sort_key *sort_key;
4164         int descending, ret = 0;
4165         unsigned int i, j, k;
4166
4167         hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
4168
4169         if (!fields_str)
4170                 goto out;
4171
4172         strsep(&fields_str, "=");
4173         if (!fields_str) {
4174                 ret = -EINVAL;
4175                 goto out;
4176         }
4177
4178         for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
4179                 struct hist_field *hist_field;
4180                 char *field_str, *field_name;
4181                 const char *test_name;
4182
4183                 sort_key = &hist_data->sort_keys[i];
4184
4185                 field_str = strsep(&fields_str, ",");
4186                 if (!field_str) {
4187                         if (i == 0)
4188                                 ret = -EINVAL;
4189                         break;
4190                 }
4191
4192                 if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
4193                         ret = -EINVAL;
4194                         break;
4195                 }
4196
4197                 field_name = strsep(&field_str, ".");
4198                 if (!field_name) {
4199                         ret = -EINVAL;
4200                         break;
4201                 }
4202
4203                 if (strcmp(field_name, "hitcount") == 0) {
4204                         descending = is_descending(field_str);
4205                         if (descending < 0) {
4206                                 ret = descending;
4207                                 break;
4208                         }
4209                         sort_key->descending = descending;
4210                         continue;
4211                 }
4212
4213                 for (j = 1, k = 1; j < hist_data->n_fields; j++) {
4214                         unsigned int idx;
4215
4216                         hist_field = hist_data->fields[j];
4217                         if (hist_field->flags & HIST_FIELD_FL_VAR)
4218                                 continue;
4219
4220                         idx = k++;
4221
4222                         test_name = hist_field_name(hist_field, 0);
4223
4224                         if (strcmp(field_name, test_name) == 0) {
4225                                 sort_key->field_idx = idx;
4226                                 descending = is_descending(field_str);
4227                                 if (descending < 0) {
4228                                         ret = descending;
4229                                         goto out;
4230                                 }
4231                                 sort_key->descending = descending;
4232                                 break;
4233                         }
4234                 }
4235                 if (j == hist_data->n_fields) {
4236                         ret = -EINVAL;
4237                         break;
4238                 }
4239         }
4240
4241         hist_data->n_sort_keys = i;
4242  out:
4243         return ret;
4244 }
4245
4246 static void destroy_actions(struct hist_trigger_data *hist_data)
4247 {
4248         unsigned int i;
4249
4250         for (i = 0; i < hist_data->n_actions; i++) {
4251                 struct action_data *data = hist_data->actions[i];
4252
4253                 if (data->fn == action_trace)
4254                         onmatch_destroy(data);
4255                 else if (data->fn == onmax_save)
4256                         onmax_destroy(data);
4257                 else
4258                         kfree(data);
4259         }
4260 }
4261
4262 static int parse_actions(struct hist_trigger_data *hist_data)
4263 {
4264         struct trace_array *tr = hist_data->event_file->tr;
4265         struct action_data *data;
4266         unsigned int i;
4267         int ret = 0;
4268         char *str;
4269
4270         for (i = 0; i < hist_data->attrs->n_actions; i++) {
4271                 str = hist_data->attrs->action_str[i];
4272
4273                 if (strncmp(str, "onmatch(", strlen("onmatch(")) == 0) {
4274                         char *action_str = str + strlen("onmatch(");
4275
4276                         data = onmatch_parse(tr, action_str);
4277                         if (IS_ERR(data)) {
4278                                 ret = PTR_ERR(data);
4279                                 break;
4280                         }
4281                         data->fn = action_trace;
4282                 } else if (strncmp(str, "onmax(", strlen("onmax(")) == 0) {
4283                         char *action_str = str + strlen("onmax(");
4284
4285                         data = onmax_parse(action_str);
4286                         if (IS_ERR(data)) {
4287                                 ret = PTR_ERR(data);
4288                                 break;
4289                         }
4290                         data->fn = onmax_save;
4291                 } else {
4292                         ret = -EINVAL;
4293                         break;
4294                 }
4295
4296                 hist_data->actions[hist_data->n_actions++] = data;
4297         }
4298
4299         return ret;
4300 }
4301
4302 static int create_actions(struct hist_trigger_data *hist_data,
4303                           struct trace_event_file *file)
4304 {
4305         struct action_data *data;
4306         unsigned int i;
4307         int ret = 0;
4308
4309         for (i = 0; i < hist_data->attrs->n_actions; i++) {
4310                 data = hist_data->actions[i];
4311
4312                 if (data->fn == action_trace) {
4313                         ret = onmatch_create(hist_data, file, data);
4314                         if (ret)
4315                                 return ret;
4316                 } else if (data->fn == onmax_save) {
4317                         ret = onmax_create(hist_data, data);
4318                         if (ret)
4319                                 return ret;
4320                 }
4321         }
4322
4323         return ret;
4324 }
4325
4326 static void print_actions(struct seq_file *m,
4327                           struct hist_trigger_data *hist_data,
4328                           struct tracing_map_elt *elt)
4329 {
4330         unsigned int i;
4331
4332         for (i = 0; i < hist_data->n_actions; i++) {
4333                 struct action_data *data = hist_data->actions[i];
4334
4335                 if (data->fn == onmax_save)
4336                         onmax_print(m, hist_data, elt, data);
4337         }
4338 }
4339
4340 static void print_onmax_spec(struct seq_file *m,
4341                              struct hist_trigger_data *hist_data,
4342                              struct action_data *data)
4343 {
4344         unsigned int i;
4345
4346         seq_puts(m, ":onmax(");
4347         seq_printf(m, "%s", data->onmax.var_str);
4348         seq_printf(m, ").%s(", data->onmax.fn_name);
4349
4350         for (i = 0; i < hist_data->n_max_vars; i++) {
4351                 seq_printf(m, "%s", hist_data->max_vars[i]->var->var.name);
4352                 if (i < hist_data->n_max_vars - 1)
4353                         seq_puts(m, ",");
4354         }
4355         seq_puts(m, ")");
4356 }
4357
4358 static void print_onmatch_spec(struct seq_file *m,
4359                                struct hist_trigger_data *hist_data,
4360                                struct action_data *data)
4361 {
4362         unsigned int i;
4363
4364         seq_printf(m, ":onmatch(%s.%s).", data->onmatch.match_event_system,
4365                    data->onmatch.match_event);
4366
4367         seq_printf(m, "%s(", data->onmatch.synth_event->name);
4368
4369         for (i = 0; i < data->n_params; i++) {
4370                 if (i)
4371                         seq_puts(m, ",");
4372                 seq_printf(m, "%s", data->params[i]);
4373         }
4374
4375         seq_puts(m, ")");
4376 }
4377
4378 static bool actions_match(struct hist_trigger_data *hist_data,
4379                           struct hist_trigger_data *hist_data_test)
4380 {
4381         unsigned int i, j;
4382
4383         if (hist_data->n_actions != hist_data_test->n_actions)
4384                 return false;
4385
4386         for (i = 0; i < hist_data->n_actions; i++) {
4387                 struct action_data *data = hist_data->actions[i];
4388                 struct action_data *data_test = hist_data_test->actions[i];
4389
4390                 if (data->fn != data_test->fn)
4391                         return false;
4392
4393                 if (data->n_params != data_test->n_params)
4394                         return false;
4395
4396                 for (j = 0; j < data->n_params; j++) {
4397                         if (strcmp(data->params[j], data_test->params[j]) != 0)
4398                                 return false;
4399                 }
4400
4401                 if (data->fn == action_trace) {
4402                         if (strcmp(data->onmatch.synth_event_name,
4403                                    data_test->onmatch.synth_event_name) != 0)
4404                                 return false;
4405                         if (strcmp(data->onmatch.match_event_system,
4406                                    data_test->onmatch.match_event_system) != 0)
4407                                 return false;
4408                         if (strcmp(data->onmatch.match_event,
4409                                    data_test->onmatch.match_event) != 0)
4410                                 return false;
4411                 } else if (data->fn == onmax_save) {
4412                         if (strcmp(data->onmax.var_str,
4413                                    data_test->onmax.var_str) != 0)
4414                                 return false;
4415                         if (strcmp(data->onmax.fn_name,
4416                                    data_test->onmax.fn_name) != 0)
4417                                 return false;
4418                 }
4419         }
4420
4421         return true;
4422 }
4423
4424
4425 static void print_actions_spec(struct seq_file *m,
4426                                struct hist_trigger_data *hist_data)
4427 {
4428         unsigned int i;
4429
4430         for (i = 0; i < hist_data->n_actions; i++) {
4431                 struct action_data *data = hist_data->actions[i];
4432
4433                 if (data->fn == action_trace)
4434                         print_onmatch_spec(m, hist_data, data);
4435                 else if (data->fn == onmax_save)
4436                         print_onmax_spec(m, hist_data, data);
4437         }
4438 }
4439
4440 static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
4441 {
4442         unsigned int i;
4443
4444         for (i = 0; i < hist_data->n_field_var_hists; i++) {
4445                 kfree(hist_data->field_var_hists[i]->cmd);
4446                 kfree(hist_data->field_var_hists[i]);
4447         }
4448 }
4449
4450 static void destroy_hist_data(struct hist_trigger_data *hist_data)
4451 {
4452         if (!hist_data)
4453                 return;
4454
4455         destroy_hist_trigger_attrs(hist_data->attrs);
4456         destroy_hist_fields(hist_data);
4457         tracing_map_destroy(hist_data->map);
4458
4459         destroy_actions(hist_data);
4460         destroy_field_vars(hist_data);
4461         destroy_field_var_hists(hist_data);
4462         destroy_synth_var_refs(hist_data);
4463
4464         kfree(hist_data);
4465 }
4466
4467 static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
4468 {
4469         struct tracing_map *map = hist_data->map;
4470         struct ftrace_event_field *field;
4471         struct hist_field *hist_field;
4472         int i, idx = 0;
4473
4474         for_each_hist_field(i, hist_data) {
4475                 hist_field = hist_data->fields[i];
4476                 if (hist_field->flags & HIST_FIELD_FL_KEY) {
4477                         tracing_map_cmp_fn_t cmp_fn;
4478
4479                         field = hist_field->field;
4480
4481                         if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
4482                                 cmp_fn = tracing_map_cmp_none;
4483                         else if (!field)
4484                                 cmp_fn = tracing_map_cmp_num(hist_field->size,
4485                                                              hist_field->is_signed);
4486                         else if (is_string_field(field))
4487                                 cmp_fn = tracing_map_cmp_string;
4488                         else
4489                                 cmp_fn = tracing_map_cmp_num(field->size,
4490                                                              field->is_signed);
4491                         idx = tracing_map_add_key_field(map,
4492                                                         hist_field->offset,
4493                                                         cmp_fn);
4494                 } else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
4495                         idx = tracing_map_add_sum_field(map);
4496
4497                 if (idx < 0)
4498                         return idx;
4499
4500                 if (hist_field->flags & HIST_FIELD_FL_VAR) {
4501                         idx = tracing_map_add_var(map);
4502                         if (idx < 0)
4503                                 return idx;
4504                         hist_field->var.idx = idx;
4505                         hist_field->var.hist_data = hist_data;
4506                 }
4507         }
4508
4509         return 0;
4510 }
4511
4512 static struct hist_trigger_data *
4513 create_hist_data(unsigned int map_bits,
4514                  struct hist_trigger_attrs *attrs,
4515                  struct trace_event_file *file,
4516                  bool remove)
4517 {
4518         const struct tracing_map_ops *map_ops = NULL;
4519         struct hist_trigger_data *hist_data;
4520         int ret = 0;
4521
4522         hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
4523         if (!hist_data)
4524                 return ERR_PTR(-ENOMEM);
4525
4526         hist_data->attrs = attrs;
4527         hist_data->remove = remove;
4528         hist_data->event_file = file;
4529
4530         ret = parse_actions(hist_data);
4531         if (ret)
4532                 goto free;
4533
4534         ret = create_hist_fields(hist_data, file);
4535         if (ret)
4536                 goto free;
4537
4538         ret = create_sort_keys(hist_data);
4539         if (ret)
4540                 goto free;
4541
4542         map_ops = &hist_trigger_elt_data_ops;
4543
4544         hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
4545                                             map_ops, hist_data);
4546         if (IS_ERR(hist_data->map)) {
4547                 ret = PTR_ERR(hist_data->map);
4548                 hist_data->map = NULL;
4549                 goto free;
4550         }
4551
4552         ret = create_tracing_map_fields(hist_data);
4553         if (ret)
4554                 goto free;
4555  out:
4556         return hist_data;
4557  free:
4558         hist_data->attrs = NULL;
4559
4560         destroy_hist_data(hist_data);
4561
4562         hist_data = ERR_PTR(ret);
4563
4564         goto out;
4565 }
4566
4567 static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
4568                                     struct tracing_map_elt *elt, void *rec,
4569                                     struct ring_buffer_event *rbe,
4570                                     u64 *var_ref_vals)
4571 {
4572         struct hist_elt_data *elt_data;
4573         struct hist_field *hist_field;
4574         unsigned int i, var_idx;
4575         u64 hist_val;
4576
4577         elt_data = elt->private_data;
4578         elt_data->var_ref_vals = var_ref_vals;
4579
4580         for_each_hist_val_field(i, hist_data) {
4581                 hist_field = hist_data->fields[i];
4582                 hist_val = hist_field->fn(hist_field, elt, rbe, rec);
4583                 if (hist_field->flags & HIST_FIELD_FL_VAR) {
4584                         var_idx = hist_field->var.idx;
4585                         tracing_map_set_var(elt, var_idx, hist_val);
4586                         continue;
4587                 }
4588                 tracing_map_update_sum(elt, i, hist_val);
4589         }
4590
4591         for_each_hist_key_field(i, hist_data) {
4592                 hist_field = hist_data->fields[i];
4593                 if (hist_field->flags & HIST_FIELD_FL_VAR) {
4594                         hist_val = hist_field->fn(hist_field, elt, rbe, rec);
4595                         var_idx = hist_field->var.idx;
4596                         tracing_map_set_var(elt, var_idx, hist_val);
4597                 }
4598         }
4599
4600         update_field_vars(hist_data, elt, rbe, rec);
4601 }
4602
4603 static inline void add_to_key(char *compound_key, void *key,
4604                               struct hist_field *key_field, void *rec)
4605 {
4606         size_t size = key_field->size;
4607
4608         if (key_field->flags & HIST_FIELD_FL_STRING) {
4609                 struct ftrace_event_field *field;
4610
4611                 field = key_field->field;
4612                 if (field->filter_type == FILTER_DYN_STRING)
4613                         size = *(u32 *)(rec + field->offset) >> 16;
4614                 else if (field->filter_type == FILTER_PTR_STRING)
4615                         size = strlen(key);
4616                 else if (field->filter_type == FILTER_STATIC_STRING)
4617                         size = field->size;
4618
4619                 /* ensure NULL-termination */
4620                 if (size > key_field->size - 1)
4621                         size = key_field->size - 1;
4622         }
4623
4624         memcpy(compound_key + key_field->offset, key, size);
4625 }
4626
4627 static void
4628 hist_trigger_actions(struct hist_trigger_data *hist_data,
4629                      struct tracing_map_elt *elt, void *rec,
4630                      struct ring_buffer_event *rbe, u64 *var_ref_vals)
4631 {
4632         struct action_data *data;
4633         unsigned int i;
4634
4635         for (i = 0; i < hist_data->n_actions; i++) {
4636                 data = hist_data->actions[i];
4637                 data->fn(hist_data, elt, rec, rbe, data, var_ref_vals);
4638         }
4639 }
4640
4641 static void event_hist_trigger(struct event_trigger_data *data, void *rec,
4642                                struct ring_buffer_event *rbe)
4643 {
4644         struct hist_trigger_data *hist_data = data->private_data;
4645         bool use_compound_key = (hist_data->n_keys > 1);
4646         unsigned long entries[HIST_STACKTRACE_DEPTH];
4647         u64 var_ref_vals[TRACING_MAP_VARS_MAX];
4648         char compound_key[HIST_KEY_SIZE_MAX];
4649         struct tracing_map_elt *elt = NULL;
4650         struct stack_trace stacktrace;
4651         struct hist_field *key_field;
4652         u64 field_contents;
4653         void *key = NULL;
4654         unsigned int i;
4655
4656         memset(compound_key, 0, hist_data->key_size);
4657
4658         for_each_hist_key_field(i, hist_data) {
4659                 key_field = hist_data->fields[i];
4660
4661                 if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
4662                         stacktrace.max_entries = HIST_STACKTRACE_DEPTH;
4663                         stacktrace.entries = entries;
4664                         stacktrace.nr_entries = 0;
4665                         stacktrace.skip = HIST_STACKTRACE_SKIP;
4666
4667                         memset(stacktrace.entries, 0, HIST_STACKTRACE_SIZE);
4668                         save_stack_trace(&stacktrace);
4669
4670                         key = entries;
4671                 } else {
4672                         field_contents = key_field->fn(key_field, elt, rbe, rec);
4673                         if (key_field->flags & HIST_FIELD_FL_STRING) {
4674                                 key = (void *)(unsigned long)field_contents;
4675                                 use_compound_key = true;
4676                         } else
4677                                 key = (void *)&field_contents;
4678                 }
4679
4680                 if (use_compound_key)
4681                         add_to_key(compound_key, key, key_field, rec);
4682         }
4683
4684         if (use_compound_key)
4685                 key = compound_key;
4686
4687         if (hist_data->n_var_refs &&
4688             !resolve_var_refs(hist_data, key, var_ref_vals, false))
4689                 return;
4690
4691         elt = tracing_map_insert(hist_data->map, key);
4692         if (!elt)
4693                 return;
4694
4695         hist_trigger_elt_update(hist_data, elt, rec, rbe, var_ref_vals);
4696
4697         if (resolve_var_refs(hist_data, key, var_ref_vals, true))
4698                 hist_trigger_actions(hist_data, elt, rec, rbe, var_ref_vals);
4699 }
4700
4701 static void hist_trigger_stacktrace_print(struct seq_file *m,
4702                                           unsigned long *stacktrace_entries,
4703                                           unsigned int max_entries)
4704 {
4705         char str[KSYM_SYMBOL_LEN];
4706         unsigned int spaces = 8;
4707         unsigned int i;
4708
4709         for (i = 0; i < max_entries; i++) {
4710                 if (stacktrace_entries[i] == ULONG_MAX)
4711                         return;
4712
4713                 seq_printf(m, "%*c", 1 + spaces, ' ');
4714                 sprint_symbol(str, stacktrace_entries[i]);
4715                 seq_printf(m, "%s\n", str);
4716         }
4717 }
4718
4719 static void
4720 hist_trigger_entry_print(struct seq_file *m,
4721                          struct hist_trigger_data *hist_data, void *key,
4722                          struct tracing_map_elt *elt)
4723 {
4724         struct hist_field *key_field;
4725         char str[KSYM_SYMBOL_LEN];
4726         bool multiline = false;
4727         const char *field_name;
4728         unsigned int i;
4729         u64 uval;
4730
4731         seq_puts(m, "{ ");
4732
4733         for_each_hist_key_field(i, hist_data) {
4734                 key_field = hist_data->fields[i];
4735
4736                 if (i > hist_data->n_vals)
4737                         seq_puts(m, ", ");
4738
4739                 field_name = hist_field_name(key_field, 0);
4740
4741                 if (key_field->flags & HIST_FIELD_FL_HEX) {
4742                         uval = *(u64 *)(key + key_field->offset);
4743                         seq_printf(m, "%s: %llx", field_name, uval);
4744                 } else if (key_field->flags & HIST_FIELD_FL_SYM) {
4745                         uval = *(u64 *)(key + key_field->offset);
4746                         sprint_symbol_no_offset(str, uval);
4747                         seq_printf(m, "%s: [%llx] %-45s", field_name,
4748                                    uval, str);
4749                 } else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
4750                         uval = *(u64 *)(key + key_field->offset);
4751                         sprint_symbol(str, uval);
4752                         seq_printf(m, "%s: [%llx] %-55s", field_name,
4753                                    uval, str);
4754                 } else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
4755                         struct hist_elt_data *elt_data = elt->private_data;
4756                         char *comm;
4757
4758                         if (WARN_ON_ONCE(!elt_data))
4759                                 return;
4760
4761                         comm = elt_data->comm;
4762
4763                         uval = *(u64 *)(key + key_field->offset);
4764                         seq_printf(m, "%s: %-16s[%10llu]", field_name,
4765                                    comm, uval);
4766                 } else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
4767                         const char *syscall_name;
4768
4769                         uval = *(u64 *)(key + key_field->offset);
4770                         syscall_name = get_syscall_name(uval);
4771                         if (!syscall_name)
4772                                 syscall_name = "unknown_syscall";
4773
4774                         seq_printf(m, "%s: %-30s[%3llu]", field_name,
4775                                    syscall_name, uval);
4776                 } else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
4777                         seq_puts(m, "stacktrace:\n");
4778                         hist_trigger_stacktrace_print(m,
4779                                                       key + key_field->offset,
4780                                                       HIST_STACKTRACE_DEPTH);
4781                         multiline = true;
4782                 } else if (key_field->flags & HIST_FIELD_FL_LOG2) {
4783                         seq_printf(m, "%s: ~ 2^%-2llu", field_name,
4784                                    *(u64 *)(key + key_field->offset));
4785                 } else if (key_field->flags & HIST_FIELD_FL_STRING) {
4786                         seq_printf(m, "%s: %-50s", field_name,
4787                                    (char *)(key + key_field->offset));
4788                 } else {
4789                         uval = *(u64 *)(key + key_field->offset);
4790                         seq_printf(m, "%s: %10llu", field_name, uval);
4791                 }
4792         }
4793
4794         if (!multiline)
4795                 seq_puts(m, " ");
4796
4797         seq_puts(m, "}");
4798
4799         seq_printf(m, " hitcount: %10llu",
4800                    tracing_map_read_sum(elt, HITCOUNT_IDX));
4801
4802         for (i = 1; i < hist_data->n_vals; i++) {
4803                 field_name = hist_field_name(hist_data->fields[i], 0);
4804
4805                 if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR ||
4806                     hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR)
4807                         continue;
4808
4809                 if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
4810                         seq_printf(m, "  %s: %10llx", field_name,
4811                                    tracing_map_read_sum(elt, i));
4812                 } else {
4813                         seq_printf(m, "  %s: %10llu", field_name,
4814                                    tracing_map_read_sum(elt, i));
4815                 }
4816         }
4817
4818         print_actions(m, hist_data, elt);
4819
4820         seq_puts(m, "\n");
4821 }
4822
4823 static int print_entries(struct seq_file *m,
4824                          struct hist_trigger_data *hist_data)
4825 {
4826         struct tracing_map_sort_entry **sort_entries = NULL;
4827         struct tracing_map *map = hist_data->map;
4828         int i, n_entries;
4829
4830         n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
4831                                              hist_data->n_sort_keys,
4832                                              &sort_entries);
4833         if (n_entries < 0)
4834                 return n_entries;
4835
4836         for (i = 0; i < n_entries; i++)
4837                 hist_trigger_entry_print(m, hist_data,
4838                                          sort_entries[i]->key,
4839                                          sort_entries[i]->elt);
4840
4841         tracing_map_destroy_sort_entries(sort_entries, n_entries);
4842
4843         return n_entries;
4844 }
4845
4846 static void hist_trigger_show(struct seq_file *m,
4847                               struct event_trigger_data *data, int n)
4848 {
4849         struct hist_trigger_data *hist_data;
4850         int n_entries;
4851
4852         if (n > 0)
4853                 seq_puts(m, "\n\n");
4854
4855         seq_puts(m, "# event histogram\n#\n# trigger info: ");
4856         data->ops->print(m, data->ops, data);
4857         seq_puts(m, "#\n\n");
4858
4859         hist_data = data->private_data;
4860         n_entries = print_entries(m, hist_data);
4861         if (n_entries < 0)
4862                 n_entries = 0;
4863
4864         seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
4865                    (u64)atomic64_read(&hist_data->map->hits),
4866                    n_entries, (u64)atomic64_read(&hist_data->map->drops));
4867 }
4868
4869 static int hist_show(struct seq_file *m, void *v)
4870 {
4871         struct event_trigger_data *data;
4872         struct trace_event_file *event_file;
4873         int n = 0, ret = 0;
4874
4875         mutex_lock(&event_mutex);
4876
4877         event_file = event_file_data(m->private);
4878         if (unlikely(!event_file)) {
4879                 ret = -ENODEV;
4880                 goto out_unlock;
4881         }
4882
4883         list_for_each_entry_rcu(data, &event_file->triggers, list) {
4884                 if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
4885                         hist_trigger_show(m, data, n++);
4886         }
4887
4888         if (have_hist_err()) {
4889                 seq_printf(m, "\nERROR: %s\n", hist_err_str);
4890                 seq_printf(m, "  Last command: %s\n", last_hist_cmd);
4891         }
4892
4893  out_unlock:
4894         mutex_unlock(&event_mutex);
4895
4896         return ret;
4897 }
4898
4899 static int event_hist_open(struct inode *inode, struct file *file)
4900 {
4901         return single_open(file, hist_show, file);
4902 }
4903
4904 const struct file_operations event_hist_fops = {
4905         .open = event_hist_open,
4906         .read = seq_read,
4907         .llseek = seq_lseek,
4908         .release = single_release,
4909 };
4910
4911 static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
4912 {
4913         const char *field_name = hist_field_name(hist_field, 0);
4914
4915         if (hist_field->var.name)
4916                 seq_printf(m, "%s=", hist_field->var.name);
4917
4918         if (hist_field->flags & HIST_FIELD_FL_CPU)
4919                 seq_puts(m, "cpu");
4920         else if (field_name) {
4921                 if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
4922                     hist_field->flags & HIST_FIELD_FL_ALIAS)
4923                         seq_putc(m, '$');
4924                 seq_printf(m, "%s", field_name);
4925         } else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
4926                 seq_puts(m, "common_timestamp");
4927
4928         if (hist_field->flags) {
4929                 if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
4930                     !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
4931                         const char *flags = get_hist_field_flags(hist_field);
4932
4933                         if (flags)
4934                                 seq_printf(m, ".%s", flags);
4935                 }
4936         }
4937 }
4938
4939 static int event_hist_trigger_print(struct seq_file *m,
4940                                     struct event_trigger_ops *ops,
4941                                     struct event_trigger_data *data)
4942 {
4943         struct hist_trigger_data *hist_data = data->private_data;
4944         struct hist_field *field;
4945         bool have_var = false;
4946         unsigned int i;
4947
4948         seq_puts(m, "hist:");
4949
4950         if (data->name)
4951                 seq_printf(m, "%s:", data->name);
4952
4953         seq_puts(m, "keys=");
4954
4955         for_each_hist_key_field(i, hist_data) {
4956                 field = hist_data->fields[i];
4957
4958                 if (i > hist_data->n_vals)
4959                         seq_puts(m, ",");
4960
4961                 if (field->flags & HIST_FIELD_FL_STACKTRACE)
4962                         seq_puts(m, "stacktrace");
4963                 else
4964                         hist_field_print(m, field);
4965         }
4966
4967         seq_puts(m, ":vals=");
4968
4969         for_each_hist_val_field(i, hist_data) {
4970                 field = hist_data->fields[i];
4971                 if (field->flags & HIST_FIELD_FL_VAR) {
4972                         have_var = true;
4973                         continue;
4974                 }
4975
4976                 if (i == HITCOUNT_IDX)
4977                         seq_puts(m, "hitcount");
4978                 else {
4979                         seq_puts(m, ",");
4980                         hist_field_print(m, field);
4981                 }
4982         }
4983
4984         if (have_var) {
4985                 unsigned int n = 0;
4986
4987                 seq_puts(m, ":");
4988
4989                 for_each_hist_val_field(i, hist_data) {
4990                         field = hist_data->fields[i];
4991
4992                         if (field->flags & HIST_FIELD_FL_VAR) {
4993                                 if (n++)
4994                                         seq_puts(m, ",");
4995                                 hist_field_print(m, field);
4996                         }
4997                 }
4998         }
4999
5000         seq_puts(m, ":sort=");
5001
5002         for (i = 0; i < hist_data->n_sort_keys; i++) {
5003                 struct tracing_map_sort_key *sort_key;
5004                 unsigned int idx, first_key_idx;
5005
5006                 /* skip VAR vals */
5007                 first_key_idx = hist_data->n_vals - hist_data->n_vars;
5008
5009                 sort_key = &hist_data->sort_keys[i];
5010                 idx = sort_key->field_idx;
5011
5012                 if (WARN_ON(idx >= HIST_FIELDS_MAX))
5013                         return -EINVAL;
5014
5015                 if (i > 0)
5016                         seq_puts(m, ",");
5017
5018                 if (idx == HITCOUNT_IDX)
5019                         seq_puts(m, "hitcount");
5020                 else {
5021                         if (idx >= first_key_idx)
5022                                 idx += hist_data->n_vars;
5023                         hist_field_print(m, hist_data->fields[idx]);
5024                 }
5025
5026                 if (sort_key->descending)
5027                         seq_puts(m, ".descending");
5028         }
5029         seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
5030         if (hist_data->enable_timestamps)
5031                 seq_printf(m, ":clock=%s", hist_data->attrs->clock);
5032
5033         print_actions_spec(m, hist_data);
5034
5035         if (data->filter_str)
5036                 seq_printf(m, " if %s", data->filter_str);
5037
5038         if (data->paused)
5039                 seq_puts(m, " [paused]");
5040         else
5041                 seq_puts(m, " [active]");
5042
5043         seq_putc(m, '\n');
5044
5045         return 0;
5046 }
5047
5048 static int event_hist_trigger_init(struct event_trigger_ops *ops,
5049                                    struct event_trigger_data *data)
5050 {
5051         struct hist_trigger_data *hist_data = data->private_data;
5052
5053         if (!data->ref && hist_data->attrs->name)
5054                 save_named_trigger(hist_data->attrs->name, data);
5055
5056         data->ref++;
5057
5058         return 0;
5059 }
5060
5061 static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
5062 {
5063         struct trace_event_file *file;
5064         unsigned int i;
5065         char *cmd;
5066         int ret;
5067
5068         for (i = 0; i < hist_data->n_field_var_hists; i++) {
5069                 file = hist_data->field_var_hists[i]->hist_data->event_file;
5070                 cmd = hist_data->field_var_hists[i]->cmd;
5071                 ret = event_hist_trigger_func(&trigger_hist_cmd, file,
5072                                               "!hist", "hist", cmd);
5073         }
5074 }
5075
5076 static void event_hist_trigger_free(struct event_trigger_ops *ops,
5077                                     struct event_trigger_data *data)
5078 {
5079         struct hist_trigger_data *hist_data = data->private_data;
5080
5081         if (WARN_ON_ONCE(data->ref <= 0))
5082                 return;
5083
5084         data->ref--;
5085         if (!data->ref) {
5086                 if (data->name)
5087                         del_named_trigger(data);
5088
5089                 trigger_data_free(data);
5090
5091                 remove_hist_vars(hist_data);
5092
5093                 unregister_field_var_hists(hist_data);
5094
5095                 destroy_hist_data(hist_data);
5096         }
5097 }
5098
5099 static struct event_trigger_ops event_hist_trigger_ops = {
5100         .func                   = event_hist_trigger,
5101         .print                  = event_hist_trigger_print,
5102         .init                   = event_hist_trigger_init,
5103         .free                   = event_hist_trigger_free,
5104 };
5105
5106 static int event_hist_trigger_named_init(struct event_trigger_ops *ops,
5107                                          struct event_trigger_data *data)
5108 {
5109         data->ref++;
5110
5111         save_named_trigger(data->named_data->name, data);
5112
5113         event_hist_trigger_init(ops, data->named_data);
5114
5115         return 0;
5116 }
5117
5118 static void event_hist_trigger_named_free(struct event_trigger_ops *ops,
5119                                           struct event_trigger_data *data)
5120 {
5121         if (WARN_ON_ONCE(data->ref <= 0))
5122                 return;
5123
5124         event_hist_trigger_free(ops, data->named_data);
5125
5126         data->ref--;
5127         if (!data->ref) {
5128                 del_named_trigger(data);
5129                 trigger_data_free(data);
5130         }
5131 }
5132
5133 static struct event_trigger_ops event_hist_trigger_named_ops = {
5134         .func                   = event_hist_trigger,
5135         .print                  = event_hist_trigger_print,
5136         .init                   = event_hist_trigger_named_init,
5137         .free                   = event_hist_trigger_named_free,
5138 };
5139
5140 static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
5141                                                             char *param)
5142 {
5143         return &event_hist_trigger_ops;
5144 }
5145
5146 static void hist_clear(struct event_trigger_data *data)
5147 {
5148         struct hist_trigger_data *hist_data = data->private_data;
5149
5150         if (data->name)
5151                 pause_named_trigger(data);
5152
5153         tracepoint_synchronize_unregister();
5154
5155         tracing_map_clear(hist_data->map);
5156
5157         if (data->name)
5158                 unpause_named_trigger(data);
5159 }
5160
5161 static bool compatible_field(struct ftrace_event_field *field,
5162                              struct ftrace_event_field *test_field)
5163 {
5164         if (field == test_field)
5165                 return true;
5166         if (field == NULL || test_field == NULL)
5167                 return false;
5168         if (strcmp(field->name, test_field->name) != 0)
5169                 return false;
5170         if (strcmp(field->type, test_field->type) != 0)
5171                 return false;
5172         if (field->size != test_field->size)
5173                 return false;
5174         if (field->is_signed != test_field->is_signed)
5175                 return false;
5176
5177         return true;
5178 }
5179
5180 static bool hist_trigger_match(struct event_trigger_data *data,
5181                                struct event_trigger_data *data_test,
5182                                struct event_trigger_data *named_data,
5183                                bool ignore_filter)
5184 {
5185         struct tracing_map_sort_key *sort_key, *sort_key_test;
5186         struct hist_trigger_data *hist_data, *hist_data_test;
5187         struct hist_field *key_field, *key_field_test;
5188         unsigned int i;
5189
5190         if (named_data && (named_data != data_test) &&
5191             (named_data != data_test->named_data))
5192                 return false;
5193
5194         if (!named_data && is_named_trigger(data_test))
5195                 return false;
5196
5197         hist_data = data->private_data;
5198         hist_data_test = data_test->private_data;
5199
5200         if (hist_data->n_vals != hist_data_test->n_vals ||
5201             hist_data->n_fields != hist_data_test->n_fields ||
5202             hist_data->n_sort_keys != hist_data_test->n_sort_keys)
5203                 return false;
5204
5205         if (!ignore_filter) {
5206                 if ((data->filter_str && !data_test->filter_str) ||
5207                    (!data->filter_str && data_test->filter_str))
5208                         return false;
5209         }
5210
5211         for_each_hist_field(i, hist_data) {
5212                 key_field = hist_data->fields[i];
5213                 key_field_test = hist_data_test->fields[i];
5214
5215                 if (key_field->flags != key_field_test->flags)
5216                         return false;
5217                 if (!compatible_field(key_field->field, key_field_test->field))
5218                         return false;
5219                 if (key_field->offset != key_field_test->offset)
5220                         return false;
5221                 if (key_field->size != key_field_test->size)
5222                         return false;
5223                 if (key_field->is_signed != key_field_test->is_signed)
5224                         return false;
5225                 if (!!key_field->var.name != !!key_field_test->var.name)
5226                         return false;
5227                 if (key_field->var.name &&
5228                     strcmp(key_field->var.name, key_field_test->var.name) != 0)
5229                         return false;
5230         }
5231
5232         for (i = 0; i < hist_data->n_sort_keys; i++) {
5233                 sort_key = &hist_data->sort_keys[i];
5234                 sort_key_test = &hist_data_test->sort_keys[i];
5235
5236                 if (sort_key->field_idx != sort_key_test->field_idx ||
5237                     sort_key->descending != sort_key_test->descending)
5238                         return false;
5239         }
5240
5241         if (!ignore_filter && data->filter_str &&
5242             (strcmp(data->filter_str, data_test->filter_str) != 0))
5243                 return false;
5244
5245         if (!actions_match(hist_data, hist_data_test))
5246                 return false;
5247
5248         return true;
5249 }
5250
5251 static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
5252                                  struct event_trigger_data *data,
5253                                  struct trace_event_file *file)
5254 {
5255         struct hist_trigger_data *hist_data = data->private_data;
5256         struct event_trigger_data *test, *named_data = NULL;
5257         int ret = 0;
5258
5259         if (hist_data->attrs->name) {
5260                 named_data = find_named_trigger(hist_data->attrs->name);
5261                 if (named_data) {
5262                         if (!hist_trigger_match(data, named_data, named_data,
5263                                                 true)) {
5264                                 hist_err("Named hist trigger doesn't match existing named trigger (includes variables): ", hist_data->attrs->name);
5265                                 ret = -EINVAL;
5266                                 goto out;
5267                         }
5268                 }
5269         }
5270
5271         if (hist_data->attrs->name && !named_data)
5272                 goto new;
5273
5274         list_for_each_entry_rcu(test, &file->triggers, list) {
5275                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5276                         if (!hist_trigger_match(data, test, named_data, false))
5277                                 continue;
5278                         if (hist_data->attrs->pause)
5279                                 test->paused = true;
5280                         else if (hist_data->attrs->cont)
5281                                 test->paused = false;
5282                         else if (hist_data->attrs->clear)
5283                                 hist_clear(test);
5284                         else {
5285                                 hist_err("Hist trigger already exists", NULL);
5286                                 ret = -EEXIST;
5287                         }
5288                         goto out;
5289                 }
5290         }
5291  new:
5292         if (hist_data->attrs->cont || hist_data->attrs->clear) {
5293                 hist_err("Can't clear or continue a nonexistent hist trigger", NULL);
5294                 ret = -ENOENT;
5295                 goto out;
5296         }
5297
5298         if (hist_data->attrs->pause)
5299                 data->paused = true;
5300
5301         if (named_data) {
5302                 data->private_data = named_data->private_data;
5303                 set_named_trigger_data(data, named_data);
5304                 data->ops = &event_hist_trigger_named_ops;
5305         }
5306
5307         if (data->ops->init) {
5308                 ret = data->ops->init(data->ops, data);
5309                 if (ret < 0)
5310                         goto out;
5311         }
5312
5313         if (hist_data->enable_timestamps) {
5314                 char *clock = hist_data->attrs->clock;
5315
5316                 ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
5317                 if (ret) {
5318                         hist_err("Couldn't set trace_clock: ", clock);
5319                         goto out;
5320                 }
5321
5322                 tracing_set_time_stamp_abs(file->tr, true);
5323         }
5324
5325         if (named_data)
5326                 destroy_hist_data(hist_data);
5327
5328         ret++;
5329  out:
5330         return ret;
5331 }
5332
5333 static int hist_trigger_enable(struct event_trigger_data *data,
5334                                struct trace_event_file *file)
5335 {
5336         int ret = 0;
5337
5338         list_add_tail_rcu(&data->list, &file->triggers);
5339
5340         update_cond_flag(file);
5341
5342         if (trace_event_trigger_enable_disable(file, 1) < 0) {
5343                 list_del_rcu(&data->list);
5344                 update_cond_flag(file);
5345                 ret--;
5346         }
5347
5348         return ret;
5349 }
5350
5351 static bool have_hist_trigger_match(struct event_trigger_data *data,
5352                                     struct trace_event_file *file)
5353 {
5354         struct hist_trigger_data *hist_data = data->private_data;
5355         struct event_trigger_data *test, *named_data = NULL;
5356         bool match = false;
5357
5358         if (hist_data->attrs->name)
5359                 named_data = find_named_trigger(hist_data->attrs->name);
5360
5361         list_for_each_entry_rcu(test, &file->triggers, list) {
5362                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5363                         if (hist_trigger_match(data, test, named_data, false)) {
5364                                 match = true;
5365                                 break;
5366                         }
5367                 }
5368         }
5369
5370         return match;
5371 }
5372
5373 static bool hist_trigger_check_refs(struct event_trigger_data *data,
5374                                     struct trace_event_file *file)
5375 {
5376         struct hist_trigger_data *hist_data = data->private_data;
5377         struct event_trigger_data *test, *named_data = NULL;
5378
5379         if (hist_data->attrs->name)
5380                 named_data = find_named_trigger(hist_data->attrs->name);
5381
5382         list_for_each_entry_rcu(test, &file->triggers, list) {
5383                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5384                         if (!hist_trigger_match(data, test, named_data, false))
5385                                 continue;
5386                         hist_data = test->private_data;
5387                         if (check_var_refs(hist_data))
5388                                 return true;
5389                         break;
5390                 }
5391         }
5392
5393         return false;
5394 }
5395
5396 static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
5397                                     struct event_trigger_data *data,
5398                                     struct trace_event_file *file)
5399 {
5400         struct hist_trigger_data *hist_data = data->private_data;
5401         struct event_trigger_data *test, *named_data = NULL;
5402         bool unregistered = false;
5403
5404         if (hist_data->attrs->name)
5405                 named_data = find_named_trigger(hist_data->attrs->name);
5406
5407         list_for_each_entry_rcu(test, &file->triggers, list) {
5408                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5409                         if (!hist_trigger_match(data, test, named_data, false))
5410                                 continue;
5411                         unregistered = true;
5412                         list_del_rcu(&test->list);
5413                         trace_event_trigger_enable_disable(file, 0);
5414                         update_cond_flag(file);
5415                         break;
5416                 }
5417         }
5418
5419         if (unregistered && test->ops->free)
5420                 test->ops->free(test->ops, test);
5421
5422         if (hist_data->enable_timestamps) {
5423                 if (!hist_data->remove || unregistered)
5424                         tracing_set_time_stamp_abs(file->tr, false);
5425         }
5426 }
5427
5428 static bool hist_file_check_refs(struct trace_event_file *file)
5429 {
5430         struct hist_trigger_data *hist_data;
5431         struct event_trigger_data *test;
5432
5433         list_for_each_entry_rcu(test, &file->triggers, list) {
5434                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5435                         hist_data = test->private_data;
5436                         if (check_var_refs(hist_data))
5437                                 return true;
5438                 }
5439         }
5440
5441         return false;
5442 }
5443
5444 static void hist_unreg_all(struct trace_event_file *file)
5445 {
5446         struct event_trigger_data *test, *n;
5447         struct hist_trigger_data *hist_data;
5448         struct synth_event *se;
5449         const char *se_name;
5450
5451         if (hist_file_check_refs(file))
5452                 return;
5453
5454         list_for_each_entry_safe(test, n, &file->triggers, list) {
5455                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5456                         hist_data = test->private_data;
5457                         list_del_rcu(&test->list);
5458                         trace_event_trigger_enable_disable(file, 0);
5459
5460                         mutex_lock(&synth_event_mutex);
5461                         se_name = trace_event_name(file->event_call);
5462                         se = find_synth_event(se_name);
5463                         if (se)
5464                                 se->ref--;
5465                         mutex_unlock(&synth_event_mutex);
5466
5467                         update_cond_flag(file);
5468                         if (hist_data->enable_timestamps)
5469                                 tracing_set_time_stamp_abs(file->tr, false);
5470                         if (test->ops->free)
5471                                 test->ops->free(test->ops, test);
5472                 }
5473         }
5474 }
5475
5476 static int event_hist_trigger_func(struct event_command *cmd_ops,
5477                                    struct trace_event_file *file,
5478                                    char *glob, char *cmd, char *param)
5479 {
5480         unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
5481         struct event_trigger_data *trigger_data;
5482         struct hist_trigger_attrs *attrs;
5483         struct event_trigger_ops *trigger_ops;
5484         struct hist_trigger_data *hist_data;
5485         struct synth_event *se;
5486         const char *se_name;
5487         bool remove = false;
5488         char *trigger, *p;
5489         int ret = 0;
5490
5491         if (glob && strlen(glob)) {
5492                 last_cmd_set(param);
5493                 hist_err_clear();
5494         }
5495
5496         if (!param)
5497                 return -EINVAL;
5498
5499         if (glob[0] == '!')
5500                 remove = true;
5501
5502         /*
5503          * separate the trigger from the filter (k:v [if filter])
5504          * allowing for whitespace in the trigger
5505          */
5506         p = trigger = param;
5507         do {
5508                 p = strstr(p, "if");
5509                 if (!p)
5510                         break;
5511                 if (p == param)
5512                         return -EINVAL;
5513                 if (*(p - 1) != ' ' && *(p - 1) != '\t') {
5514                         p++;
5515                         continue;
5516                 }
5517                 if (p >= param + strlen(param) - strlen("if") - 1)
5518                         return -EINVAL;
5519                 if (*(p + strlen("if")) != ' ' && *(p + strlen("if")) != '\t') {
5520                         p++;
5521                         continue;
5522                 }
5523                 break;
5524         } while (p);
5525
5526         if (!p)
5527                 param = NULL;
5528         else {
5529                 *(p - 1) = '\0';
5530                 param = strstrip(p);
5531                 trigger = strstrip(trigger);
5532         }
5533
5534         attrs = parse_hist_trigger_attrs(trigger);
5535         if (IS_ERR(attrs))
5536                 return PTR_ERR(attrs);
5537
5538         if (attrs->map_bits)
5539                 hist_trigger_bits = attrs->map_bits;
5540
5541         hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
5542         if (IS_ERR(hist_data)) {
5543                 destroy_hist_trigger_attrs(attrs);
5544                 return PTR_ERR(hist_data);
5545         }
5546
5547         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
5548
5549         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
5550         if (!trigger_data) {
5551                 ret = -ENOMEM;
5552                 goto out_free;
5553         }
5554
5555         trigger_data->count = -1;
5556         trigger_data->ops = trigger_ops;
5557         trigger_data->cmd_ops = cmd_ops;
5558
5559         INIT_LIST_HEAD(&trigger_data->list);
5560         RCU_INIT_POINTER(trigger_data->filter, NULL);
5561
5562         trigger_data->private_data = hist_data;
5563
5564         /* if param is non-empty, it's supposed to be a filter */
5565         if (param && cmd_ops->set_filter) {
5566                 ret = cmd_ops->set_filter(param, trigger_data, file);
5567                 if (ret < 0)
5568                         goto out_free;
5569         }
5570
5571         if (remove) {
5572                 if (!have_hist_trigger_match(trigger_data, file))
5573                         goto out_free;
5574
5575                 if (hist_trigger_check_refs(trigger_data, file)) {
5576                         ret = -EBUSY;
5577                         goto out_free;
5578                 }
5579
5580                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
5581
5582                 mutex_lock(&synth_event_mutex);
5583                 se_name = trace_event_name(file->event_call);
5584                 se = find_synth_event(se_name);
5585                 if (se)
5586                         se->ref--;
5587                 mutex_unlock(&synth_event_mutex);
5588
5589                 ret = 0;
5590                 goto out_free;
5591         }
5592
5593         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
5594         /*
5595          * The above returns on success the # of triggers registered,
5596          * but if it didn't register any it returns zero.  Consider no
5597          * triggers registered a failure too.
5598          */
5599         if (!ret) {
5600                 if (!(attrs->pause || attrs->cont || attrs->clear))
5601                         ret = -ENOENT;
5602                 goto out_free;
5603         } else if (ret < 0)
5604                 goto out_free;
5605
5606         if (get_named_trigger_data(trigger_data))
5607                 goto enable;
5608
5609         if (has_hist_vars(hist_data))
5610                 save_hist_vars(hist_data);
5611
5612         ret = create_actions(hist_data, file);
5613         if (ret)
5614                 goto out_unreg;
5615
5616         ret = tracing_map_init(hist_data->map);
5617         if (ret)
5618                 goto out_unreg;
5619 enable:
5620         ret = hist_trigger_enable(trigger_data, file);
5621         if (ret)
5622                 goto out_unreg;
5623
5624         mutex_lock(&synth_event_mutex);
5625         se_name = trace_event_name(file->event_call);
5626         se = find_synth_event(se_name);
5627         if (se)
5628                 se->ref++;
5629         mutex_unlock(&synth_event_mutex);
5630
5631         /* Just return zero, not the number of registered triggers */
5632         ret = 0;
5633  out:
5634         if (ret == 0)
5635                 hist_err_clear();
5636
5637         return ret;
5638  out_unreg:
5639         cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
5640  out_free:
5641         if (cmd_ops->set_filter)
5642                 cmd_ops->set_filter(NULL, trigger_data, NULL);
5643
5644         remove_hist_vars(hist_data);
5645
5646         kfree(trigger_data);
5647
5648         destroy_hist_data(hist_data);
5649         goto out;
5650 }
5651
5652 static struct event_command trigger_hist_cmd = {
5653         .name                   = "hist",
5654         .trigger_type           = ETT_EVENT_HIST,
5655         .flags                  = EVENT_CMD_FL_NEEDS_REC,
5656         .func                   = event_hist_trigger_func,
5657         .reg                    = hist_register_trigger,
5658         .unreg                  = hist_unregister_trigger,
5659         .unreg_all              = hist_unreg_all,
5660         .get_trigger_ops        = event_hist_get_trigger_ops,
5661         .set_filter             = set_trigger_filter,
5662 };
5663
5664 __init int register_trigger_hist_cmd(void)
5665 {
5666         int ret;
5667
5668         ret = register_event_command(&trigger_hist_cmd);
5669         WARN_ON(ret < 0);
5670
5671         return ret;
5672 }
5673
5674 static void
5675 hist_enable_trigger(struct event_trigger_data *data, void *rec,
5676                     struct ring_buffer_event *event)
5677 {
5678         struct enable_trigger_data *enable_data = data->private_data;
5679         struct event_trigger_data *test;
5680
5681         list_for_each_entry_rcu(test, &enable_data->file->triggers, list) {
5682                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5683                         if (enable_data->enable)
5684                                 test->paused = false;
5685                         else
5686                                 test->paused = true;
5687                 }
5688         }
5689 }
5690
5691 static void
5692 hist_enable_count_trigger(struct event_trigger_data *data, void *rec,
5693                           struct ring_buffer_event *event)
5694 {
5695         if (!data->count)
5696                 return;
5697
5698         if (data->count != -1)
5699                 (data->count)--;
5700
5701         hist_enable_trigger(data, rec, event);
5702 }
5703
5704 static struct event_trigger_ops hist_enable_trigger_ops = {
5705         .func                   = hist_enable_trigger,
5706         .print                  = event_enable_trigger_print,
5707         .init                   = event_trigger_init,
5708         .free                   = event_enable_trigger_free,
5709 };
5710
5711 static struct event_trigger_ops hist_enable_count_trigger_ops = {
5712         .func                   = hist_enable_count_trigger,
5713         .print                  = event_enable_trigger_print,
5714         .init                   = event_trigger_init,
5715         .free                   = event_enable_trigger_free,
5716 };
5717
5718 static struct event_trigger_ops hist_disable_trigger_ops = {
5719         .func                   = hist_enable_trigger,
5720         .print                  = event_enable_trigger_print,
5721         .init                   = event_trigger_init,
5722         .free                   = event_enable_trigger_free,
5723 };
5724
5725 static struct event_trigger_ops hist_disable_count_trigger_ops = {
5726         .func                   = hist_enable_count_trigger,
5727         .print                  = event_enable_trigger_print,
5728         .init                   = event_trigger_init,
5729         .free                   = event_enable_trigger_free,
5730 };
5731
5732 static struct event_trigger_ops *
5733 hist_enable_get_trigger_ops(char *cmd, char *param)
5734 {
5735         struct event_trigger_ops *ops;
5736         bool enable;
5737
5738         enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
5739
5740         if (enable)
5741                 ops = param ? &hist_enable_count_trigger_ops :
5742                         &hist_enable_trigger_ops;
5743         else
5744                 ops = param ? &hist_disable_count_trigger_ops :
5745                         &hist_disable_trigger_ops;
5746
5747         return ops;
5748 }
5749
5750 static void hist_enable_unreg_all(struct trace_event_file *file)
5751 {
5752         struct event_trigger_data *test, *n;
5753
5754         list_for_each_entry_safe(test, n, &file->triggers, list) {
5755                 if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
5756                         list_del_rcu(&test->list);
5757                         update_cond_flag(file);
5758                         trace_event_trigger_enable_disable(file, 0);
5759                         if (test->ops->free)
5760                                 test->ops->free(test->ops, test);
5761                 }
5762         }
5763 }
5764
5765 static struct event_command trigger_hist_enable_cmd = {
5766         .name                   = ENABLE_HIST_STR,
5767         .trigger_type           = ETT_HIST_ENABLE,
5768         .func                   = event_enable_trigger_func,
5769         .reg                    = event_enable_register_trigger,
5770         .unreg                  = event_enable_unregister_trigger,
5771         .unreg_all              = hist_enable_unreg_all,
5772         .get_trigger_ops        = hist_enable_get_trigger_ops,
5773         .set_filter             = set_trigger_filter,
5774 };
5775
5776 static struct event_command trigger_hist_disable_cmd = {
5777         .name                   = DISABLE_HIST_STR,
5778         .trigger_type           = ETT_HIST_ENABLE,
5779         .func                   = event_enable_trigger_func,
5780         .reg                    = event_enable_register_trigger,
5781         .unreg                  = event_enable_unregister_trigger,
5782         .unreg_all              = hist_enable_unreg_all,
5783         .get_trigger_ops        = hist_enable_get_trigger_ops,
5784         .set_filter             = set_trigger_filter,
5785 };
5786
5787 static __init void unregister_trigger_hist_enable_disable_cmds(void)
5788 {
5789         unregister_event_command(&trigger_hist_enable_cmd);
5790         unregister_event_command(&trigger_hist_disable_cmd);
5791 }
5792
5793 __init int register_trigger_hist_enable_disable_cmds(void)
5794 {
5795         int ret;
5796
5797         ret = register_event_command(&trigger_hist_enable_cmd);
5798         if (WARN_ON(ret < 0))
5799                 return ret;
5800         ret = register_event_command(&trigger_hist_disable_cmd);
5801         if (WARN_ON(ret < 0))
5802                 unregister_trigger_hist_enable_disable_cmds();
5803
5804         return ret;
5805 }
5806
5807 static __init int trace_events_hist_init(void)
5808 {
5809         struct dentry *entry = NULL;
5810         struct dentry *d_tracer;
5811         int err = 0;
5812
5813         d_tracer = tracing_init_dentry();
5814         if (IS_ERR(d_tracer)) {
5815                 err = PTR_ERR(d_tracer);
5816                 goto err;
5817         }
5818
5819         entry = tracefs_create_file("synthetic_events", 0644, d_tracer,
5820                                     NULL, &synth_events_fops);
5821         if (!entry) {
5822                 err = -ENODEV;
5823                 goto err;
5824         }
5825
5826         return err;
5827  err:
5828         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
5829
5830         return err;
5831 }
5832
5833 fs_initcall(trace_events_hist_init);