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/security.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/stacktrace.h>
  14 #include <linux/rculist.h>
  15 #include <linux/tracefs.h>
  16
  17 /* for gfp flag names */
  18 #include <linux/trace_events.h>
  19 #include <trace/events/mmflags.h>
  20
  21 #include "tracing_map.h"
  22 #include "trace_synth.h"
  23
  24 #define ERRORS                                                          \
  25         C(NONE,                 "No error"),                            \
  26         C(DUPLICATE_VAR,        "Variable already defined"),            \
  27         C(VAR_NOT_UNIQUE,       "Variable name not unique, need to use fully qualified name (subsys.event.var) for variable"), \
  28         C(TOO_MANY_VARS,        "Too many variables defined"),          \
  29         C(MALFORMED_ASSIGNMENT, "Malformed assignment"),                \
  30         C(NAMED_MISMATCH,       "Named hist trigger doesn't match existing named trigger (includes variables)"), \
  31         C(TRIGGER_EEXIST,       "Hist trigger already exists"),         \
  32         C(TRIGGER_ENOENT_CLEAR, "Can't clear or continue a nonexistent hist trigger"), \
  33         C(SET_CLOCK_FAIL,       "Couldn't set trace_clock"),            \
  34         C(BAD_FIELD_MODIFIER,   "Invalid field modifier"),              \
  35         C(TOO_MANY_SUBEXPR,     "Too many subexpressions (3 max)"),     \
  36         C(TIMESTAMP_MISMATCH,   "Timestamp units in expression don't match"), \
  37         C(TOO_MANY_FIELD_VARS,  "Too many field variables defined"),    \
  38         C(EVENT_FILE_NOT_FOUND, "Event file not found"),                \
  39         C(HIST_NOT_FOUND,       "Matching event histogram not found"),  \
  40         C(HIST_CREATE_FAIL,     "Couldn't create histogram for field"), \
  41         C(SYNTH_VAR_NOT_FOUND,  "Couldn't find synthetic variable"),    \
  42         C(SYNTH_EVENT_NOT_FOUND,"Couldn't find synthetic event"),       \
  43         C(SYNTH_TYPE_MISMATCH,  "Param type doesn't match synthetic event field type"), \
  44         C(SYNTH_COUNT_MISMATCH, "Param count doesn't match synthetic event field count"), \
  45         C(FIELD_VAR_PARSE_FAIL, "Couldn't parse field variable"),       \
  46         C(VAR_CREATE_FIND_FAIL, "Couldn't create or find variable"),    \
  47         C(ONX_NOT_VAR,          "For onmax(x) or onchange(x), x must be a variable"), \
  48         C(ONX_VAR_NOT_FOUND,    "Couldn't find onmax or onchange variable"), \
  49         C(ONX_VAR_CREATE_FAIL,  "Couldn't create onmax or onchange variable"), \
  50         C(FIELD_VAR_CREATE_FAIL,"Couldn't create field variable"),      \
  51         C(TOO_MANY_PARAMS,      "Too many action params"),              \
  52         C(PARAM_NOT_FOUND,      "Couldn't find param"),                 \
  53         C(INVALID_PARAM,        "Invalid action param"),                \
  54         C(ACTION_NOT_FOUND,     "No action found"),                     \
  55         C(NO_SAVE_PARAMS,       "No params found for save()"),          \
  56         C(TOO_MANY_SAVE_ACTIONS,"Can't have more than one save() action per hist"), \
  57         C(ACTION_MISMATCH,      "Handler doesn't support action"),      \
  58         C(NO_CLOSING_PAREN,     "No closing paren found"),              \
  59         C(SUBSYS_NOT_FOUND,     "Missing subsystem"),                   \
  60         C(INVALID_SUBSYS_EVENT, "Invalid subsystem or event name"),     \
  61         C(INVALID_REF_KEY,      "Using variable references in keys not supported"), \
  62         C(VAR_NOT_FOUND,        "Couldn't find variable"),              \
  63         C(FIELD_NOT_FOUND,      "Couldn't find field"),                 \
  64         C(EMPTY_ASSIGNMENT,     "Empty assignment"),                    \
  65         C(INVALID_SORT_MODIFIER,"Invalid sort modifier"),               \
  66         C(EMPTY_SORT_FIELD,     "Empty sort field"),                    \
  67         C(TOO_MANY_SORT_FIELDS, "Too many sort fields (Max = 2)"),      \
  68         C(INVALID_SORT_FIELD,   "Sort field must be a key or a val"),   \
  69         C(INVALID_STR_OPERAND,  "String type can not be an operand in expression"), \
  70         C(EXPECT_NUMBER,        "Expecting numeric literal"),           \
  71         C(UNARY_MINUS_SUBEXPR,  "Unary minus not supported in sub-expressions"), \
  72         C(DIVISION_BY_ZERO,     "Division by zero"),
  73
  74 #undef C
  75 #define C(a, b)         HIST_ERR_##a
  76
  77 enum { ERRORS };
  78
  79 #undef C
  80 #define C(a, b)         b
  81
  82 static const char *err_text[] = { ERRORS };
  83
  84 struct hist_field;
  85
  86 typedef u64 (*hist_field_fn_t) (struct hist_field *field,
  87                                 struct tracing_map_elt *elt,
  88                                 struct trace_buffer *buffer,
  89                                 struct ring_buffer_event *rbe,
  90                                 void *event);
  91
  92 #define HIST_FIELD_OPERANDS_MAX 2
  93 #define HIST_FIELDS_MAX         (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
  94 #define HIST_ACTIONS_MAX        8
  95 #define HIST_CONST_DIGITS_MAX   21
  96 #define HIST_DIV_SHIFT          20  /* For optimizing division by constants */
  97
  98 enum field_op_id {
  99         FIELD_OP_NONE,
 100         FIELD_OP_PLUS,
 101         FIELD_OP_MINUS,
 102         FIELD_OP_UNARY_MINUS,
 103         FIELD_OP_DIV,
 104         FIELD_OP_MULT,
 105 };
 106
 107 /*
 108  * A hist_var (histogram variable) contains variable information for
 109  * hist_fields having the HIST_FIELD_FL_VAR or HIST_FIELD_FL_VAR_REF
 110  * flag set.  A hist_var has a variable name e.g. ts0, and is
 111  * associated with a given histogram trigger, as specified by
 112  * hist_data.  The hist_var idx is the unique index assigned to the
 113  * variable by the hist trigger's tracing_map.  The idx is what is
 114  * used to set a variable's value and, by a variable reference, to
 115  * retrieve it.
 116  */
 117 struct hist_var {
 118         char                            *name;
 119         struct hist_trigger_data        *hist_data;
 120         unsigned int                    idx;
 121 };
 122
 123 struct hist_field {
 124         struct ftrace_event_field       *field;
 125         unsigned long                   flags;
 126         hist_field_fn_t                 fn;
 127         unsigned int                    ref;
 128         unsigned int                    size;
 129         unsigned int                    offset;
 130         unsigned int                    is_signed;
 131         unsigned long                   buckets;
 132         const char                      *type;
 133         struct hist_field               *operands[HIST_FIELD_OPERANDS_MAX];
 134         struct hist_trigger_data        *hist_data;
 135
 136         /*
 137          * Variable fields contain variable-specific info in var.
 138          */
 139         struct hist_var                 var;
 140         enum field_op_id                operator;
 141         char                            *system;
 142         char                            *event_name;
 143
 144         /*
 145          * The name field is used for EXPR and VAR_REF fields.  VAR
 146          * fields contain the variable name in var.name.
 147          */
 148         char                            *name;
 149
 150         /*
 151          * When a histogram trigger is hit, if it has any references
 152          * to variables, the values of those variables are collected
 153          * into a var_ref_vals array by resolve_var_refs().  The
 154          * current value of each variable is read from the tracing_map
 155          * using the hist field's hist_var.idx and entered into the
 156          * var_ref_idx entry i.e. var_ref_vals[var_ref_idx].
 157          */
 158         unsigned int                    var_ref_idx;
 159         bool                            read_once;
 160
 161         unsigned int                    var_str_idx;
 162
 163         /* Numeric literals are represented as u64 */
 164         u64                             constant;
 165         /* Used to optimize division by constants */
 166         u64                             div_multiplier;
 167 };
 168
 169 static u64 hist_field_none(struct hist_field *field,
 170                            struct tracing_map_elt *elt,
 171                            struct trace_buffer *buffer,
 172                            struct ring_buffer_event *rbe,
 173                            void *event)
 174 {
 175         return 0;
 176 }
 177
 178 static u64 hist_field_const(struct hist_field *field,
 179                            struct tracing_map_elt *elt,
 180                            struct trace_buffer *buffer,
 181                            struct ring_buffer_event *rbe,
 182                            void *event)
 183 {
 184         return field->constant;
 185 }
 186
 187 static u64 hist_field_counter(struct hist_field *field,
 188                               struct tracing_map_elt *elt,
 189                               struct trace_buffer *buffer,
 190                               struct ring_buffer_event *rbe,
 191                               void *event)
 192 {
 193         return 1;
 194 }
 195
 196 static u64 hist_field_string(struct hist_field *hist_field,
 197                              struct tracing_map_elt *elt,
 198                              struct trace_buffer *buffer,
 199                              struct ring_buffer_event *rbe,
 200                              void *event)
 201 {
 202         char *addr = (char *)(event + hist_field->field->offset);
 203
 204         return (u64)(unsigned long)addr;
 205 }
 206
 207 static u64 hist_field_dynstring(struct hist_field *hist_field,
 208                                 struct tracing_map_elt *elt,
 209                                 struct trace_buffer *buffer,
 210                                 struct ring_buffer_event *rbe,
 211                                 void *event)
 212 {
 213         u32 str_item = *(u32 *)(event + hist_field->field->offset);
 214         int str_loc = str_item & 0xffff;
 215         char *addr = (char *)(event + str_loc);
 216
 217         return (u64)(unsigned long)addr;
 218 }
 219
 220 static u64 hist_field_reldynstring(struct hist_field *hist_field,
 221                                    struct tracing_map_elt *elt,
 222                                    struct trace_buffer *buffer,
 223                                    struct ring_buffer_event *rbe,
 224                                    void *event)
 225 {
 226         u32 *item = event + hist_field->field->offset;
 227         u32 str_item = *item;
 228         int str_loc = str_item & 0xffff;
 229         char *addr = (char *)&item[1] + str_loc;
 230
 231         return (u64)(unsigned long)addr;
 232 }
 233
 234 static u64 hist_field_pstring(struct hist_field *hist_field,
 235                               struct tracing_map_elt *elt,
 236                               struct trace_buffer *buffer,
 237                               struct ring_buffer_event *rbe,
 238                               void *event)
 239 {
 240         char **addr = (char **)(event + hist_field->field->offset);
 241
 242         return (u64)(unsigned long)*addr;
 243 }
 244
 245 static u64 hist_field_log2(struct hist_field *hist_field,
 246                            struct tracing_map_elt *elt,
 247                            struct trace_buffer *buffer,
 248                            struct ring_buffer_event *rbe,
 249                            void *event)
 250 {
 251         struct hist_field *operand = hist_field->operands[0];
 252
 253         u64 val = operand->fn(operand, elt, buffer, rbe, event);
 254
 255         return (u64) ilog2(roundup_pow_of_two(val));
 256 }
 257
 258 static u64 hist_field_bucket(struct hist_field *hist_field,
 259                              struct tracing_map_elt *elt,
 260                              struct trace_buffer *buffer,
 261                              struct ring_buffer_event *rbe,
 262                              void *event)
 263 {
 264         struct hist_field *operand = hist_field->operands[0];
 265         unsigned long buckets = hist_field->buckets;
 266
 267         u64 val = operand->fn(operand, elt, buffer, rbe, event);
 268
 269         if (WARN_ON_ONCE(!buckets))
 270                 return val;
 271
 272         if (val >= LONG_MAX)
 273                 val = div64_ul(val, buckets);
 274         else
 275                 val = (u64)((unsigned long)val / buckets);
 276         return val * buckets;
 277 }
 278
 279 static u64 hist_field_plus(struct hist_field *hist_field,
 280                            struct tracing_map_elt *elt,
 281                            struct trace_buffer *buffer,
 282                            struct ring_buffer_event *rbe,
 283                            void *event)
 284 {
 285         struct hist_field *operand1 = hist_field->operands[0];
 286         struct hist_field *operand2 = hist_field->operands[1];
 287
 288         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 289         u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
 290
 291         return val1 + val2;
 292 }
 293
 294 static u64 hist_field_minus(struct hist_field *hist_field,
 295                             struct tracing_map_elt *elt,
 296                             struct trace_buffer *buffer,
 297                             struct ring_buffer_event *rbe,
 298                             void *event)
 299 {
 300         struct hist_field *operand1 = hist_field->operands[0];
 301         struct hist_field *operand2 = hist_field->operands[1];
 302
 303         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 304         u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
 305
 306         return val1 - val2;
 307 }
 308
 309 static u64 hist_field_div(struct hist_field *hist_field,
 310                            struct tracing_map_elt *elt,
 311                            struct trace_buffer *buffer,
 312                            struct ring_buffer_event *rbe,
 313                            void *event)
 314 {
 315         struct hist_field *operand1 = hist_field->operands[0];
 316         struct hist_field *operand2 = hist_field->operands[1];
 317
 318         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 319         u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
 320
 321         /* Return -1 for the undefined case */
 322         if (!val2)
 323                 return -1;
 324
 325         /* Use shift if the divisor is a power of 2 */
 326         if (!(val2 & (val2 - 1)))
 327                 return val1 >> __ffs64(val2);
 328
 329         return div64_u64(val1, val2);
 330 }
 331
 332 static u64 div_by_power_of_two(struct hist_field *hist_field,
 333                                 struct tracing_map_elt *elt,
 334                                 struct trace_buffer *buffer,
 335                                 struct ring_buffer_event *rbe,
 336                                 void *event)
 337 {
 338         struct hist_field *operand1 = hist_field->operands[0];
 339         struct hist_field *operand2 = hist_field->operands[1];
 340
 341         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 342
 343         return val1 >> __ffs64(operand2->constant);
 344 }
 345
 346 static u64 div_by_not_power_of_two(struct hist_field *hist_field,
 347                                 struct tracing_map_elt *elt,
 348                                 struct trace_buffer *buffer,
 349                                 struct ring_buffer_event *rbe,
 350                                 void *event)
 351 {
 352         struct hist_field *operand1 = hist_field->operands[0];
 353         struct hist_field *operand2 = hist_field->operands[1];
 354
 355         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 356
 357         return div64_u64(val1, operand2->constant);
 358 }
 359
 360 static u64 div_by_mult_and_shift(struct hist_field *hist_field,
 361                                 struct tracing_map_elt *elt,
 362                                 struct trace_buffer *buffer,
 363                                 struct ring_buffer_event *rbe,
 364                                 void *event)
 365 {
 366         struct hist_field *operand1 = hist_field->operands[0];
 367         struct hist_field *operand2 = hist_field->operands[1];
 368
 369         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 370
 371         /*
 372          * If the divisor is a constant, do a multiplication and shift instead.
 373          *
 374          * Choose Z = some power of 2. If Y <= Z, then:
 375          *     X / Y = (X * (Z / Y)) / Z
 376          *
 377          * (Z / Y) is a constant (mult) which is calculated at parse time, so:
 378          *     X / Y = (X * mult) / Z
 379          *
 380          * The division by Z can be replaced by a shift since Z is a power of 2:
 381          *     X / Y = (X * mult) >> HIST_DIV_SHIFT
 382          *
 383          * As long, as X < Z the results will not be off by more than 1.
 384          */
 385         if (val1 < (1 << HIST_DIV_SHIFT)) {
 386                 u64 mult = operand2->div_multiplier;
 387
 388                 return (val1 * mult + ((1 << HIST_DIV_SHIFT) - 1)) >> HIST_DIV_SHIFT;
 389         }
 390
 391         return div64_u64(val1, operand2->constant);
 392 }
 393
 394 static u64 hist_field_mult(struct hist_field *hist_field,
 395                            struct tracing_map_elt *elt,
 396                            struct trace_buffer *buffer,
 397                            struct ring_buffer_event *rbe,
 398                            void *event)
 399 {
 400         struct hist_field *operand1 = hist_field->operands[0];
 401         struct hist_field *operand2 = hist_field->operands[1];
 402
 403         u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
 404         u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
 405
 406         return val1 * val2;
 407 }
 408
 409 static u64 hist_field_unary_minus(struct hist_field *hist_field,
 410                                   struct tracing_map_elt *elt,
 411                                   struct trace_buffer *buffer,
 412                                   struct ring_buffer_event *rbe,
 413                                   void *event)
 414 {
 415         struct hist_field *operand = hist_field->operands[0];
 416
 417         s64 sval = (s64)operand->fn(operand, elt, buffer, rbe, event);
 418         u64 val = (u64)-sval;
 419
 420         return val;
 421 }
 422
 423 #define DEFINE_HIST_FIELD_FN(type)                                      \
 424         static u64 hist_field_##type(struct hist_field *hist_field,     \
 425                                      struct tracing_map_elt *elt,       \
 426                                      struct trace_buffer *buffer,       \
 427                                      struct ring_buffer_event *rbe,     \
 428                                      void *event)                       \
 429 {                                                                       \
 430         type *addr = (type *)(event + hist_field->field->offset);       \
 431                                                                         \
 432         return (u64)(unsigned long)*addr;                               \
 433 }
 434
 435 DEFINE_HIST_FIELD_FN(s64);
 436 DEFINE_HIST_FIELD_FN(u64);
 437 DEFINE_HIST_FIELD_FN(s32);
 438 DEFINE_HIST_FIELD_FN(u32);
 439 DEFINE_HIST_FIELD_FN(s16);
 440 DEFINE_HIST_FIELD_FN(u16);
 441 DEFINE_HIST_FIELD_FN(s8);
 442 DEFINE_HIST_FIELD_FN(u8);
 443
 444 #define for_each_hist_field(i, hist_data)       \
 445         for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
 446
 447 #define for_each_hist_val_field(i, hist_data)   \
 448         for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
 449
 450 #define for_each_hist_key_field(i, hist_data)   \
 451         for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
 452
 453 #define HIST_STACKTRACE_DEPTH   16
 454 #define HIST_STACKTRACE_SIZE    (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
 455 #define HIST_STACKTRACE_SKIP    5
 456
 457 #define HITCOUNT_IDX            0
 458 #define HIST_KEY_SIZE_MAX       (MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
 459
 460 enum hist_field_flags {
 461         HIST_FIELD_FL_HITCOUNT          = 1 << 0,
 462         HIST_FIELD_FL_KEY               = 1 << 1,
 463         HIST_FIELD_FL_STRING            = 1 << 2,
 464         HIST_FIELD_FL_HEX               = 1 << 3,
 465         HIST_FIELD_FL_SYM               = 1 << 4,
 466         HIST_FIELD_FL_SYM_OFFSET        = 1 << 5,
 467         HIST_FIELD_FL_EXECNAME          = 1 << 6,
 468         HIST_FIELD_FL_SYSCALL           = 1 << 7,
 469         HIST_FIELD_FL_STACKTRACE        = 1 << 8,
 470         HIST_FIELD_FL_LOG2              = 1 << 9,
 471         HIST_FIELD_FL_TIMESTAMP         = 1 << 10,
 472         HIST_FIELD_FL_TIMESTAMP_USECS   = 1 << 11,
 473         HIST_FIELD_FL_VAR               = 1 << 12,
 474         HIST_FIELD_FL_EXPR              = 1 << 13,
 475         HIST_FIELD_FL_VAR_REF           = 1 << 14,
 476         HIST_FIELD_FL_CPU               = 1 << 15,
 477         HIST_FIELD_FL_ALIAS             = 1 << 16,
 478         HIST_FIELD_FL_BUCKET            = 1 << 17,
 479         HIST_FIELD_FL_CONST             = 1 << 18,
 480 };
 481
 482 struct var_defs {
 483         unsigned int    n_vars;
 484         char            *name[TRACING_MAP_VARS_MAX];
 485         char            *expr[TRACING_MAP_VARS_MAX];
 486 };
 487
 488 struct hist_trigger_attrs {
 489         char            *keys_str;
 490         char            *vals_str;
 491         char            *sort_key_str;
 492         char            *name;
 493         char            *clock;
 494         bool            pause;
 495         bool            cont;
 496         bool            clear;
 497         bool            ts_in_usecs;
 498         unsigned int    map_bits;
 499
 500         char            *assignment_str[TRACING_MAP_VARS_MAX];
 501         unsigned int    n_assignments;
 502
 503         char            *action_str[HIST_ACTIONS_MAX];
 504         unsigned int    n_actions;
 505
 506         struct var_defs var_defs;
 507 };
 508
 509 struct field_var {
 510         struct hist_field       *var;
 511         struct hist_field       *val;
 512 };
 513
 514 struct field_var_hist {
 515         struct hist_trigger_data        *hist_data;
 516         char                            *cmd;
 517 };
 518
 519 struct hist_trigger_data {
 520         struct hist_field               *fields[HIST_FIELDS_MAX];
 521         unsigned int                    n_vals;
 522         unsigned int                    n_keys;
 523         unsigned int                    n_fields;
 524         unsigned int                    n_vars;
 525         unsigned int                    n_var_str;
 526         unsigned int                    key_size;
 527         struct tracing_map_sort_key     sort_keys[TRACING_MAP_SORT_KEYS_MAX];
 528         unsigned int                    n_sort_keys;
 529         struct trace_event_file         *event_file;
 530         struct hist_trigger_attrs       *attrs;
 531         struct tracing_map              *map;
 532         bool                            enable_timestamps;
 533         bool                            remove;
 534         struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
 535         unsigned int                    n_var_refs;
 536
 537         struct action_data              *actions[HIST_ACTIONS_MAX];
 538         unsigned int                    n_actions;
 539
 540         struct field_var                *field_vars[SYNTH_FIELDS_MAX];
 541         unsigned int                    n_field_vars;
 542         unsigned int                    n_field_var_str;
 543         struct field_var_hist           *field_var_hists[SYNTH_FIELDS_MAX];
 544         unsigned int                    n_field_var_hists;
 545
 546         struct field_var                *save_vars[SYNTH_FIELDS_MAX];
 547         unsigned int                    n_save_vars;
 548         unsigned int                    n_save_var_str;
 549 };
 550
 551 struct action_data;
 552
 553 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
 554                              struct tracing_map_elt *elt,
 555                              struct trace_buffer *buffer, void *rec,
 556                              struct ring_buffer_event *rbe, void *key,
 557                              struct action_data *data, u64 *var_ref_vals);
 558
 559 typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
 560
 561 enum handler_id {
 562         HANDLER_ONMATCH = 1,
 563         HANDLER_ONMAX,
 564         HANDLER_ONCHANGE,
 565 };
 566
 567 enum action_id {
 568         ACTION_SAVE = 1,
 569         ACTION_TRACE,
 570         ACTION_SNAPSHOT,
 571 };
 572
 573 struct action_data {
 574         enum handler_id         handler;
 575         enum action_id          action;
 576         char                    *action_name;
 577         action_fn_t             fn;
 578
 579         unsigned int            n_params;
 580         char                    *params[SYNTH_FIELDS_MAX];
 581
 582         /*
 583          * When a histogram trigger is hit, the values of any
 584          * references to variables, including variables being passed
 585          * as parameters to synthetic events, are collected into a
 586          * var_ref_vals array.  This var_ref_idx array is an array of
 587          * indices into the var_ref_vals array, one for each synthetic
 588          * event param, and is passed to the synthetic event
 589          * invocation.
 590          */
 591         unsigned int            var_ref_idx[TRACING_MAP_VARS_MAX];
 592         struct synth_event      *synth_event;
 593         bool                    use_trace_keyword;
 594         char                    *synth_event_name;
 595
 596         union {
 597                 struct {
 598                         char                    *event;
 599                         char                    *event_system;
 600                 } match_data;
 601
 602                 struct {
 603                         /*
 604                          * var_str contains the $-unstripped variable
 605                          * name referenced by var_ref, and used when
 606                          * printing the action.  Because var_ref
 607                          * creation is deferred to create_actions(),
 608                          * we need a per-action way to save it until
 609                          * then, thus var_str.
 610                          */
 611                         char                    *var_str;
 612
 613                         /*
 614                          * var_ref refers to the variable being
 615                          * tracked e.g onmax($var).
 616                          */
 617                         struct hist_field       *var_ref;
 618
 619                         /*
 620                          * track_var contains the 'invisible' tracking
 621                          * variable created to keep the current
 622                          * e.g. max value.
 623                          */
 624                         struct hist_field       *track_var;
 625
 626                         check_track_val_fn_t    check_val;
 627                         action_fn_t             save_data;
 628                 } track_data;
 629         };
 630 };
 631
 632 struct track_data {
 633         u64                             track_val;
 634         bool                            updated;
 635
 636         unsigned int                    key_len;
 637         void                            *key;
 638         struct tracing_map_elt          elt;
 639
 640         struct action_data              *action_data;
 641         struct hist_trigger_data        *hist_data;
 642 };
 643
 644 struct hist_elt_data {
 645         char *comm;
 646         u64 *var_ref_vals;
 647         char **field_var_str;
 648         int n_field_var_str;
 649 };
 650
 651 struct snapshot_context {
 652         struct tracing_map_elt  *elt;
 653         void                    *key;
 654 };
 655
 656 /*
 657  * Returns the specific division function to use if the divisor
 658  * is constant. This avoids extra branches when the trigger is hit.
 659  */
 660 static hist_field_fn_t hist_field_get_div_fn(struct hist_field *divisor)
 661 {
 662         u64 div = divisor->constant;
 663
 664         if (!(div & (div - 1)))
 665                 return div_by_power_of_two;
 666
 667         /* If the divisor is too large, do a regular division */
 668         if (div > (1 << HIST_DIV_SHIFT))
 669                 return div_by_not_power_of_two;
 670
 671         divisor->div_multiplier = div64_u64((u64)(1 << HIST_DIV_SHIFT), div);
 672         return div_by_mult_and_shift;
 673 }
 674
 675 static void track_data_free(struct track_data *track_data)
 676 {
 677         struct hist_elt_data *elt_data;
 678
 679         if (!track_data)
 680                 return;
 681
 682         kfree(track_data->key);
 683
 684         elt_data = track_data->elt.private_data;
 685         if (elt_data) {
 686                 kfree(elt_data->comm);
 687                 kfree(elt_data);
 688         }
 689
 690         kfree(track_data);
 691 }
 692
 693 static struct track_data *track_data_alloc(unsigned int key_len,
 694                                            struct action_data *action_data,
 695                                            struct hist_trigger_data *hist_data)
 696 {
 697         struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
 698         struct hist_elt_data *elt_data;
 699
 700         if (!data)
 701                 return ERR_PTR(-ENOMEM);
 702
 703         data->key = kzalloc(key_len, GFP_KERNEL);
 704         if (!data->key) {
 705                 track_data_free(data);
 706                 return ERR_PTR(-ENOMEM);
 707         }
 708
 709         data->key_len = key_len;
 710         data->action_data = action_data;
 711         data->hist_data = hist_data;
 712
 713         elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
 714         if (!elt_data) {
 715                 track_data_free(data);
 716                 return ERR_PTR(-ENOMEM);
 717         }
 718
 719         data->elt.private_data = elt_data;
 720
 721         elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
 722         if (!elt_data->comm) {
 723                 track_data_free(data);
 724                 return ERR_PTR(-ENOMEM);
 725         }
 726
 727         return data;
 728 }
 729
 730 #define HIST_PREFIX "hist:"
 731
 732 static char *last_cmd;
 733 static char last_cmd_loc[MAX_FILTER_STR_VAL];
 734
 735 static int errpos(char *str)
 736 {
 737         if (!str || !last_cmd)
 738                 return 0;
 739
 740         return err_pos(last_cmd, str);
 741 }
 742
 743 static void last_cmd_set(struct trace_event_file *file, char *str)
 744 {
 745         const char *system = NULL, *name = NULL;
 746         struct trace_event_call *call;
 747         int len;
 748
 749         if (!str)
 750                 return;
 751
 752         /* sizeof() contains the nul byte */
 753         len = sizeof(HIST_PREFIX) + strlen(str);
 754         kfree(last_cmd);
 755         last_cmd = kzalloc(len, GFP_KERNEL);
 756         if (!last_cmd)
 757                 return;
 758
 759         strcpy(last_cmd, HIST_PREFIX);
 760         /* Again, sizeof() contains the nul byte */
 761         len -= sizeof(HIST_PREFIX);
 762         strncat(last_cmd, str, len);
 763
 764         if (file) {
 765                 call = file->event_call;
 766                 system = call->class->system;
 767                 if (system) {
 768                         name = trace_event_name(call);
 769                         if (!name)
 770                                 system = NULL;
 771                 }
 772         }
 773
 774         if (system)
 775                 snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name);
 776 }
 777
 778 static void hist_err(struct trace_array *tr, u8 err_type, u16 err_pos)
 779 {
 780         if (!last_cmd)
 781                 return;
 782
 783         tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
 784                         err_type, err_pos);
 785 }
 786
 787 static void hist_err_clear(void)
 788 {
 789         if (last_cmd)
 790                 last_cmd[0] = '\0';
 791         last_cmd_loc[0] = '\0';
 792 }
 793
 794 typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
 795                                     unsigned int *var_ref_idx);
 796
 797 static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
 798                                unsigned int *var_ref_idx)
 799 {
 800         struct tracepoint *tp = event->tp;
 801
 802         if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
 803                 struct tracepoint_func *probe_func_ptr;
 804                 synth_probe_func_t probe_func;
 805                 void *__data;
 806
 807                 if (!(cpu_online(raw_smp_processor_id())))
 808                         return;
 809
 810                 probe_func_ptr = rcu_dereference_sched((tp)->funcs);
 811                 if (probe_func_ptr) {
 812                         do {
 813                                 probe_func = probe_func_ptr->func;
 814                                 __data = probe_func_ptr->data;
 815                                 probe_func(__data, var_ref_vals, var_ref_idx);
 816                         } while ((++probe_func_ptr)->func);
 817                 }
 818         }
 819 }
 820
 821 static void action_trace(struct hist_trigger_data *hist_data,
 822                          struct tracing_map_elt *elt,
 823                          struct trace_buffer *buffer, void *rec,
 824                          struct ring_buffer_event *rbe, void *key,
 825                          struct action_data *data, u64 *var_ref_vals)
 826 {
 827         struct synth_event *event = data->synth_event;
 828
 829         trace_synth(event, var_ref_vals, data->var_ref_idx);
 830 }
 831
 832 struct hist_var_data {
 833         struct list_head list;
 834         struct hist_trigger_data *hist_data;
 835 };
 836
 837 static u64 hist_field_timestamp(struct hist_field *hist_field,
 838                                 struct tracing_map_elt *elt,
 839                                 struct trace_buffer *buffer,
 840                                 struct ring_buffer_event *rbe,
 841                                 void *event)
 842 {
 843         struct hist_trigger_data *hist_data = hist_field->hist_data;
 844         struct trace_array *tr = hist_data->event_file->tr;
 845
 846         u64 ts = ring_buffer_event_time_stamp(buffer, rbe);
 847
 848         if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
 849                 ts = ns2usecs(ts);
 850
 851         return ts;
 852 }
 853
 854 static u64 hist_field_cpu(struct hist_field *hist_field,
 855                           struct tracing_map_elt *elt,
 856                           struct trace_buffer *buffer,
 857                           struct ring_buffer_event *rbe,
 858                           void *event)
 859 {
 860         int cpu = smp_processor_id();
 861
 862         return cpu;
 863 }
 864
 865 /**
 866  * check_field_for_var_ref - Check if a VAR_REF field references a variable
 867  * @hist_field: The VAR_REF field to check
 868  * @var_data: The hist trigger that owns the variable
 869  * @var_idx: The trigger variable identifier
 870  *
 871  * Check the given VAR_REF field to see whether or not it references
 872  * the given variable associated with the given trigger.
 873  *
 874  * Return: The VAR_REF field if it does reference the variable, NULL if not
 875  */
 876 static struct hist_field *
 877 check_field_for_var_ref(struct hist_field *hist_field,
 878                         struct hist_trigger_data *var_data,
 879                         unsigned int var_idx)
 880 {
 881         WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));
 882
 883         if (hist_field && hist_field->var.idx == var_idx &&
 884             hist_field->var.hist_data == var_data)
 885                 return hist_field;
 886
 887         return NULL;
 888 }
 889
 890 /**
 891  * find_var_ref - Check if a trigger has a reference to a trigger variable
 892  * @hist_data: The hist trigger that might have a reference to the variable
 893  * @var_data: The hist trigger that owns the variable
 894  * @var_idx: The trigger variable identifier
 895  *
 896  * Check the list of var_refs[] on the first hist trigger to see
 897  * whether any of them are references to the variable on the second
 898  * trigger.
 899  *
 900  * Return: The VAR_REF field referencing the variable if so, NULL if not
 901  */
 902 static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
 903                                        struct hist_trigger_data *var_data,
 904                                        unsigned int var_idx)
 905 {
 906         struct hist_field *hist_field;
 907         unsigned int i;
 908
 909         for (i = 0; i < hist_data->n_var_refs; i++) {
 910                 hist_field = hist_data->var_refs[i];
 911                 if (check_field_for_var_ref(hist_field, var_data, var_idx))
 912                         return hist_field;
 913         }
 914
 915         return NULL;
 916 }
 917
 918 /**
 919  * find_any_var_ref - Check if there is a reference to a given trigger variable
 920  * @hist_data: The hist trigger
 921  * @var_idx: The trigger variable identifier
 922  *
 923  * Check to see whether the given variable is currently referenced by
 924  * any other trigger.
 925  *
 926  * The trigger the variable is defined on is explicitly excluded - the
 927  * assumption being that a self-reference doesn't prevent a trigger
 928  * from being removed.
 929  *
 930  * Return: The VAR_REF field referencing the variable if so, NULL if not
 931  */
 932 static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
 933                                            unsigned int var_idx)
 934 {
 935         struct trace_array *tr = hist_data->event_file->tr;
 936         struct hist_field *found = NULL;
 937         struct hist_var_data *var_data;
 938
 939         list_for_each_entry(var_data, &tr->hist_vars, list) {
 940                 if (var_data->hist_data == hist_data)
 941                         continue;
 942                 found = find_var_ref(var_data->hist_data, hist_data, var_idx);
 943                 if (found)
 944                         break;
 945         }
 946
 947         return found;
 948 }
 949
 950 /**
 951  * check_var_refs - Check if there is a reference to any of trigger's variables
 952  * @hist_data: The hist trigger
 953  *
 954  * A trigger can define one or more variables.  If any one of them is
 955  * currently referenced by any other trigger, this function will
 956  * determine that.
 957
 958  * Typically used to determine whether or not a trigger can be removed
 959  * - if there are any references to a trigger's variables, it cannot.
 960  *
 961  * Return: True if there is a reference to any of trigger's variables
 962  */
 963 static bool check_var_refs(struct hist_trigger_data *hist_data)
 964 {
 965         struct hist_field *field;
 966         bool found = false;
 967         int i;
 968
 969         for_each_hist_field(i, hist_data) {
 970                 field = hist_data->fields[i];
 971                 if (field && field->flags & HIST_FIELD_FL_VAR) {
 972                         if (find_any_var_ref(hist_data, field->var.idx)) {
 973                                 found = true;
 974                                 break;
 975                         }
 976                 }
 977         }
 978
 979         return found;
 980 }
 981
 982 static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
 983 {
 984         struct trace_array *tr = hist_data->event_file->tr;
 985         struct hist_var_data *var_data, *found = NULL;
 986
 987         list_for_each_entry(var_data, &tr->hist_vars, list) {
 988                 if (var_data->hist_data == hist_data) {
 989                         found = var_data;
 990                         break;
 991                 }
 992         }
 993
 994         return found;
 995 }
 996
 997 static bool field_has_hist_vars(struct hist_field *hist_field,
 998                                 unsigned int level)
 999 {
1000         int i;
1001
1002         if (level > 3)
1003                 return false;
1004
1005         if (!hist_field)
1006                 return false;
1007
1008         if (hist_field->flags & HIST_FIELD_FL_VAR ||
1009             hist_field->flags & HIST_FIELD_FL_VAR_REF)
1010                 return true;
1011
1012         for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
1013                 struct hist_field *operand;
1014
1015                 operand = hist_field->operands[i];
1016                 if (field_has_hist_vars(operand, level + 1))
1017                         return true;
1018         }
1019
1020         return false;
1021 }
1022
1023 static bool has_hist_vars(struct hist_trigger_data *hist_data)
1024 {
1025         struct hist_field *hist_field;
1026         int i;
1027
1028         for_each_hist_field(i, hist_data) {
1029                 hist_field = hist_data->fields[i];
1030                 if (field_has_hist_vars(hist_field, 0))
1031                         return true;
1032         }
1033
1034         return false;
1035 }
1036
1037 static int save_hist_vars(struct hist_trigger_data *hist_data)
1038 {
1039         struct trace_array *tr = hist_data->event_file->tr;
1040         struct hist_var_data *var_data;
1041
1042         var_data = find_hist_vars(hist_data);
1043         if (var_data)
1044                 return 0;
1045
1046         if (tracing_check_open_get_tr(tr))
1047                 return -ENODEV;
1048
1049         var_data = kzalloc(sizeof(*var_data), GFP_KERNEL);
1050         if (!var_data) {
1051                 trace_array_put(tr);
1052                 return -ENOMEM;
1053         }
1054
1055         var_data->hist_data = hist_data;
1056         list_add(&var_data->list, &tr->hist_vars);
1057
1058         return 0;
1059 }
1060
1061 static void remove_hist_vars(struct hist_trigger_data *hist_data)
1062 {
1063         struct trace_array *tr = hist_data->event_file->tr;
1064         struct hist_var_data *var_data;
1065
1066         var_data = find_hist_vars(hist_data);
1067         if (!var_data)
1068                 return;
1069
1070         if (WARN_ON(check_var_refs(hist_data)))
1071                 return;
1072
1073         list_del(&var_data->list);
1074
1075         kfree(var_data);
1076
1077         trace_array_put(tr);
1078 }
1079
1080 static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
1081                                          const char *var_name)
1082 {
1083         struct hist_field *hist_field, *found = NULL;
1084         int i;
1085
1086         for_each_hist_field(i, hist_data) {
1087                 hist_field = hist_data->fields[i];
1088                 if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
1089                     strcmp(hist_field->var.name, var_name) == 0) {
1090                         found = hist_field;
1091                         break;
1092                 }
1093         }
1094
1095         return found;
1096 }
1097
1098 static struct hist_field *find_var(struct hist_trigger_data *hist_data,
1099                                    struct trace_event_file *file,
1100                                    const char *var_name)
1101 {
1102         struct hist_trigger_data *test_data;
1103         struct event_trigger_data *test;
1104         struct hist_field *hist_field;
1105
1106         lockdep_assert_held(&event_mutex);
1107
1108         hist_field = find_var_field(hist_data, var_name);
1109         if (hist_field)
1110                 return hist_field;
1111
1112         list_for_each_entry(test, &file->triggers, list) {
1113                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1114                         test_data = test->private_data;
1115                         hist_field = find_var_field(test_data, var_name);
1116                         if (hist_field)
1117                                 return hist_field;
1118                 }
1119         }
1120
1121         return NULL;
1122 }
1123
1124 static struct trace_event_file *find_var_file(struct trace_array *tr,
1125                                               char *system,
1126                                               char *event_name,
1127                                               char *var_name)
1128 {
1129         struct hist_trigger_data *var_hist_data;
1130         struct hist_var_data *var_data;
1131         struct trace_event_file *file, *found = NULL;
1132
1133         if (system)
1134                 return find_event_file(tr, system, event_name);
1135
1136         list_for_each_entry(var_data, &tr->hist_vars, list) {
1137                 var_hist_data = var_data->hist_data;
1138                 file = var_hist_data->event_file;
1139                 if (file == found)
1140                         continue;
1141
1142                 if (find_var_field(var_hist_data, var_name)) {
1143                         if (found) {
1144                                 hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE, errpos(var_name));
1145                                 return NULL;
1146                         }
1147
1148                         found = file;
1149                 }
1150         }
1151
1152         return found;
1153 }
1154
1155 static struct hist_field *find_file_var(struct trace_event_file *file,
1156                                         const char *var_name)
1157 {
1158         struct hist_trigger_data *test_data;
1159         struct event_trigger_data *test;
1160         struct hist_field *hist_field;
1161
1162         lockdep_assert_held(&event_mutex);
1163
1164         list_for_each_entry(test, &file->triggers, list) {
1165                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1166                         test_data = test->private_data;
1167                         hist_field = find_var_field(test_data, var_name);
1168                         if (hist_field)
1169                                 return hist_field;
1170                 }
1171         }
1172
1173         return NULL;
1174 }
1175
1176 static struct hist_field *
1177 find_match_var(struct hist_trigger_data *hist_data, char *var_name)
1178 {
1179         struct trace_array *tr = hist_data->event_file->tr;
1180         struct hist_field *hist_field, *found = NULL;
1181         struct trace_event_file *file;
1182         unsigned int i;
1183
1184         for (i = 0; i < hist_data->n_actions; i++) {
1185                 struct action_data *data = hist_data->actions[i];
1186
1187                 if (data->handler == HANDLER_ONMATCH) {
1188                         char *system = data->match_data.event_system;
1189                         char *event_name = data->match_data.event;
1190
1191                         file = find_var_file(tr, system, event_name, var_name);
1192                         if (!file)
1193                                 continue;
1194                         hist_field = find_file_var(file, var_name);
1195                         if (hist_field) {
1196                                 if (found) {
1197                                         hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE,
1198                                                  errpos(var_name));
1199                                         return ERR_PTR(-EINVAL);
1200                                 }
1201
1202                                 found = hist_field;
1203                         }
1204                 }
1205         }
1206         return found;
1207 }
1208
1209 static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
1210                                          char *system,
1211                                          char *event_name,
1212                                          char *var_name)
1213 {
1214         struct trace_array *tr = hist_data->event_file->tr;
1215         struct hist_field *hist_field = NULL;
1216         struct trace_event_file *file;
1217
1218         if (!system || !event_name) {
1219                 hist_field = find_match_var(hist_data, var_name);
1220                 if (IS_ERR(hist_field))
1221                         return NULL;
1222                 if (hist_field)
1223                         return hist_field;
1224         }
1225
1226         file = find_var_file(tr, system, event_name, var_name);
1227         if (!file)
1228                 return NULL;
1229
1230         hist_field = find_file_var(file, var_name);
1231
1232         return hist_field;
1233 }
1234
1235 static u64 hist_field_var_ref(struct hist_field *hist_field,
1236                               struct tracing_map_elt *elt,
1237                               struct trace_buffer *buffer,
1238                               struct ring_buffer_event *rbe,
1239                               void *event)
1240 {
1241         struct hist_elt_data *elt_data;
1242         u64 var_val = 0;
1243
1244         if (WARN_ON_ONCE(!elt))
1245                 return var_val;
1246
1247         elt_data = elt->private_data;
1248         var_val = elt_data->var_ref_vals[hist_field->var_ref_idx];
1249
1250         return var_val;
1251 }
1252
1253 static bool resolve_var_refs(struct hist_trigger_data *hist_data, void *key,
1254                              u64 *var_ref_vals, bool self)
1255 {
1256         struct hist_trigger_data *var_data;
1257         struct tracing_map_elt *var_elt;
1258         struct hist_field *hist_field;
1259         unsigned int i, var_idx;
1260         bool resolved = true;
1261         u64 var_val = 0;
1262
1263         for (i = 0; i < hist_data->n_var_refs; i++) {
1264                 hist_field = hist_data->var_refs[i];
1265                 var_idx = hist_field->var.idx;
1266                 var_data = hist_field->var.hist_data;
1267
1268                 if (var_data == NULL) {
1269                         resolved = false;
1270                         break;
1271                 }
1272
1273                 if ((self && var_data != hist_data) ||
1274                     (!self && var_data == hist_data))
1275                         continue;
1276
1277                 var_elt = tracing_map_lookup(var_data->map, key);
1278                 if (!var_elt) {
1279                         resolved = false;
1280                         break;
1281                 }
1282
1283                 if (!tracing_map_var_set(var_elt, var_idx)) {
1284                         resolved = false;
1285                         break;
1286                 }
1287
1288                 if (self || !hist_field->read_once)
1289                         var_val = tracing_map_read_var(var_elt, var_idx);
1290                 else
1291                         var_val = tracing_map_read_var_once(var_elt, var_idx);
1292
1293                 var_ref_vals[i] = var_val;
1294         }
1295
1296         return resolved;
1297 }
1298
1299 static const char *hist_field_name(struct hist_field *field,
1300                                    unsigned int level)
1301 {
1302         const char *field_name = "";
1303
1304         if (level > 1)
1305                 return field_name;
1306
1307         if (field->field)
1308                 field_name = field->field->name;
1309         else if (field->flags & HIST_FIELD_FL_LOG2 ||
1310                  field->flags & HIST_FIELD_FL_ALIAS ||
1311                  field->flags & HIST_FIELD_FL_BUCKET)
1312                 field_name = hist_field_name(field->operands[0], ++level);
1313         else if (field->flags & HIST_FIELD_FL_CPU)
1314                 field_name = "common_cpu";
1315         else if (field->flags & HIST_FIELD_FL_EXPR ||
1316                  field->flags & HIST_FIELD_FL_VAR_REF) {
1317                 if (field->system) {
1318                         static char full_name[MAX_FILTER_STR_VAL];
1319
1320                         strcat(full_name, field->system);
1321                         strcat(full_name, ".");
1322                         strcat(full_name, field->event_name);
1323                         strcat(full_name, ".");
1324                         strcat(full_name, field->name);
1325                         field_name = full_name;
1326                 } else
1327                         field_name = field->name;
1328         } else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
1329                 field_name = "common_timestamp";
1330
1331         if (field_name == NULL)
1332                 field_name = "";
1333
1334         return field_name;
1335 }
1336
1337 static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
1338 {
1339         hist_field_fn_t fn = NULL;
1340
1341         switch (field_size) {
1342         case 8:
1343                 if (field_is_signed)
1344                         fn = hist_field_s64;
1345                 else
1346                         fn = hist_field_u64;
1347                 break;
1348         case 4:
1349                 if (field_is_signed)
1350                         fn = hist_field_s32;
1351                 else
1352                         fn = hist_field_u32;
1353                 break;
1354         case 2:
1355                 if (field_is_signed)
1356                         fn = hist_field_s16;
1357                 else
1358                         fn = hist_field_u16;
1359                 break;
1360         case 1:
1361                 if (field_is_signed)
1362                         fn = hist_field_s8;
1363                 else
1364                         fn = hist_field_u8;
1365                 break;
1366         }
1367
1368         return fn;
1369 }
1370
1371 static int parse_map_size(char *str)
1372 {
1373         unsigned long size, map_bits;
1374         int ret;
1375
1376         ret = kstrtoul(str, 0, &size);
1377         if (ret)
1378                 goto out;
1379
1380         map_bits = ilog2(roundup_pow_of_two(size));
1381         if (map_bits < TRACING_MAP_BITS_MIN ||
1382             map_bits > TRACING_MAP_BITS_MAX)
1383                 ret = -EINVAL;
1384         else
1385                 ret = map_bits;
1386  out:
1387         return ret;
1388 }
1389
1390 static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
1391 {
1392         unsigned int i;
1393
1394         if (!attrs)
1395                 return;
1396
1397         for (i = 0; i < attrs->n_assignments; i++)
1398                 kfree(attrs->assignment_str[i]);
1399
1400         for (i = 0; i < attrs->n_actions; i++)
1401                 kfree(attrs->action_str[i]);
1402
1403         kfree(attrs->name);
1404         kfree(attrs->sort_key_str);
1405         kfree(attrs->keys_str);
1406         kfree(attrs->vals_str);
1407         kfree(attrs->clock);
1408         kfree(attrs);
1409 }
1410
1411 static int parse_action(char *str, struct hist_trigger_attrs *attrs)
1412 {
1413         int ret = -EINVAL;
1414
1415         if (attrs->n_actions >= HIST_ACTIONS_MAX)
1416                 return ret;
1417
1418         if ((str_has_prefix(str, "onmatch(")) ||
1419             (str_has_prefix(str, "onmax(")) ||
1420             (str_has_prefix(str, "onchange("))) {
1421                 attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
1422                 if (!attrs->action_str[attrs->n_actions]) {
1423                         ret = -ENOMEM;
1424                         return ret;
1425                 }
1426                 attrs->n_actions++;
1427                 ret = 0;
1428         }
1429         return ret;
1430 }
1431
1432 static int parse_assignment(struct trace_array *tr,
1433                             char *str, struct hist_trigger_attrs *attrs)
1434 {
1435         int len, ret = 0;
1436
1437         if ((len = str_has_prefix(str, "key=")) ||
1438             (len = str_has_prefix(str, "keys="))) {
1439                 attrs->keys_str = kstrdup(str + len, GFP_KERNEL);
1440                 if (!attrs->keys_str) {
1441                         ret = -ENOMEM;
1442                         goto out;
1443                 }
1444         } else if ((len = str_has_prefix(str, "val=")) ||
1445                    (len = str_has_prefix(str, "vals=")) ||
1446                    (len = str_has_prefix(str, "values="))) {
1447                 attrs->vals_str = kstrdup(str + len, GFP_KERNEL);
1448                 if (!attrs->vals_str) {
1449                         ret = -ENOMEM;
1450                         goto out;
1451                 }
1452         } else if ((len = str_has_prefix(str, "sort="))) {
1453                 attrs->sort_key_str = kstrdup(str + len, GFP_KERNEL);
1454                 if (!attrs->sort_key_str) {
1455                         ret = -ENOMEM;
1456                         goto out;
1457                 }
1458         } else if (str_has_prefix(str, "name=")) {
1459                 attrs->name = kstrdup(str, GFP_KERNEL);
1460                 if (!attrs->name) {
1461                         ret = -ENOMEM;
1462                         goto out;
1463                 }
1464         } else if ((len = str_has_prefix(str, "clock="))) {
1465                 str += len;
1466
1467                 str = strstrip(str);
1468                 attrs->clock = kstrdup(str, GFP_KERNEL);
1469                 if (!attrs->clock) {
1470                         ret = -ENOMEM;
1471                         goto out;
1472                 }
1473         } else if ((len = str_has_prefix(str, "size="))) {
1474                 int map_bits = parse_map_size(str + len);
1475
1476                 if (map_bits < 0) {
1477                         ret = map_bits;
1478                         goto out;
1479                 }
1480                 attrs->map_bits = map_bits;
1481         } else {
1482                 char *assignment;
1483
1484                 if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
1485                         hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(str));
1486                         ret = -EINVAL;
1487                         goto out;
1488                 }
1489
1490                 assignment = kstrdup(str, GFP_KERNEL);
1491                 if (!assignment) {
1492                         ret = -ENOMEM;
1493                         goto out;
1494                 }
1495
1496                 attrs->assignment_str[attrs->n_assignments++] = assignment;
1497         }
1498  out:
1499         return ret;
1500 }
1501
1502 static struct hist_trigger_attrs *
1503 parse_hist_trigger_attrs(struct trace_array *tr, char *trigger_str)
1504 {
1505         struct hist_trigger_attrs *attrs;
1506         int ret = 0;
1507
1508         attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
1509         if (!attrs)
1510                 return ERR_PTR(-ENOMEM);
1511
1512         while (trigger_str) {
1513                 char *str = strsep(&trigger_str, ":");
1514                 char *rhs;
1515
1516                 rhs = strchr(str, '=');
1517                 if (rhs) {
1518                         if (!strlen(++rhs)) {
1519                                 ret = -EINVAL;
1520                                 hist_err(tr, HIST_ERR_EMPTY_ASSIGNMENT, errpos(str));
1521                                 goto free;
1522                         }
1523                         ret = parse_assignment(tr, str, attrs);
1524                         if (ret)
1525                                 goto free;
1526                 } else if (strcmp(str, "pause") == 0)
1527                         attrs->pause = true;
1528                 else if ((strcmp(str, "cont") == 0) ||
1529                          (strcmp(str, "continue") == 0))
1530                         attrs->cont = true;
1531                 else if (strcmp(str, "clear") == 0)
1532                         attrs->clear = true;
1533                 else {
1534                         ret = parse_action(str, attrs);
1535                         if (ret)
1536                                 goto free;
1537                 }
1538         }
1539
1540         if (!attrs->keys_str) {
1541                 ret = -EINVAL;
1542                 goto free;
1543         }
1544
1545         if (!attrs->clock) {
1546                 attrs->clock = kstrdup("global", GFP_KERNEL);
1547                 if (!attrs->clock) {
1548                         ret = -ENOMEM;
1549                         goto free;
1550                 }
1551         }
1552
1553         return attrs;
1554  free:
1555         destroy_hist_trigger_attrs(attrs);
1556
1557         return ERR_PTR(ret);
1558 }
1559
1560 static inline void save_comm(char *comm, struct task_struct *task)
1561 {
1562         if (!task->pid) {
1563                 strcpy(comm, "<idle>");
1564                 return;
1565         }
1566
1567         if (WARN_ON_ONCE(task->pid < 0)) {
1568                 strcpy(comm, "<XXX>");
1569                 return;
1570         }
1571
1572         strncpy(comm, task->comm, TASK_COMM_LEN);
1573 }
1574
1575 static void hist_elt_data_free(struct hist_elt_data *elt_data)
1576 {
1577         unsigned int i;
1578
1579         for (i = 0; i < elt_data->n_field_var_str; i++)
1580                 kfree(elt_data->field_var_str[i]);
1581
1582         kfree(elt_data->field_var_str);
1583
1584         kfree(elt_data->comm);
1585         kfree(elt_data);
1586 }
1587
1588 static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
1589 {
1590         struct hist_elt_data *elt_data = elt->private_data;
1591
1592         hist_elt_data_free(elt_data);
1593 }
1594
1595 static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
1596 {
1597         struct hist_trigger_data *hist_data = elt->map->private_data;
1598         unsigned int size = TASK_COMM_LEN;
1599         struct hist_elt_data *elt_data;
1600         struct hist_field *hist_field;
1601         unsigned int i, n_str;
1602
1603         elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
1604         if (!elt_data)
1605                 return -ENOMEM;
1606
1607         for_each_hist_field(i, hist_data) {
1608                 hist_field = hist_data->fields[i];
1609
1610                 if (hist_field->flags & HIST_FIELD_FL_EXECNAME) {
1611                         elt_data->comm = kzalloc(size, GFP_KERNEL);
1612                         if (!elt_data->comm) {
1613                                 kfree(elt_data);
1614                                 return -ENOMEM;
1615                         }
1616                         break;
1617                 }
1618         }
1619
1620         n_str = hist_data->n_field_var_str + hist_data->n_save_var_str +
1621                 hist_data->n_var_str;
1622         if (n_str > SYNTH_FIELDS_MAX) {
1623                 hist_elt_data_free(elt_data);
1624                 return -EINVAL;
1625         }
1626
1627         BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1));
1628
1629         size = STR_VAR_LEN_MAX;
1630
1631         elt_data->field_var_str = kcalloc(n_str, sizeof(char *), GFP_KERNEL);
1632         if (!elt_data->field_var_str) {
1633                 hist_elt_data_free(elt_data);
1634                 return -EINVAL;
1635         }
1636         elt_data->n_field_var_str = n_str;
1637
1638         for (i = 0; i < n_str; i++) {
1639                 elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
1640                 if (!elt_data->field_var_str[i]) {
1641                         hist_elt_data_free(elt_data);
1642                         return -ENOMEM;
1643                 }
1644         }
1645
1646         elt->private_data = elt_data;
1647
1648         return 0;
1649 }
1650
1651 static void hist_trigger_elt_data_init(struct tracing_map_elt *elt)
1652 {
1653         struct hist_elt_data *elt_data = elt->private_data;
1654
1655         if (elt_data->comm)
1656                 save_comm(elt_data->comm, current);
1657 }
1658
1659 static const struct tracing_map_ops hist_trigger_elt_data_ops = {
1660         .elt_alloc      = hist_trigger_elt_data_alloc,
1661         .elt_free       = hist_trigger_elt_data_free,
1662         .elt_init       = hist_trigger_elt_data_init,
1663 };
1664
1665 static const char *get_hist_field_flags(struct hist_field *hist_field)
1666 {
1667         const char *flags_str = NULL;
1668
1669         if (hist_field->flags & HIST_FIELD_FL_HEX)
1670                 flags_str = "hex";
1671         else if (hist_field->flags & HIST_FIELD_FL_SYM)
1672                 flags_str = "sym";
1673         else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
1674                 flags_str = "sym-offset";
1675         else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
1676                 flags_str = "execname";
1677         else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
1678                 flags_str = "syscall";
1679         else if (hist_field->flags & HIST_FIELD_FL_LOG2)
1680                 flags_str = "log2";
1681         else if (hist_field->flags & HIST_FIELD_FL_BUCKET)
1682                 flags_str = "buckets";
1683         else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
1684                 flags_str = "usecs";
1685
1686         return flags_str;
1687 }
1688
1689 static void expr_field_str(struct hist_field *field, char *expr)
1690 {
1691         if (field->flags & HIST_FIELD_FL_VAR_REF)
1692                 strcat(expr, "$");
1693         else if (field->flags & HIST_FIELD_FL_CONST) {
1694                 char str[HIST_CONST_DIGITS_MAX];
1695
1696                 snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant);
1697                 strcat(expr, str);
1698         }
1699
1700         strcat(expr, hist_field_name(field, 0));
1701
1702         if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) {
1703                 const char *flags_str = get_hist_field_flags(field);
1704
1705                 if (flags_str) {
1706                         strcat(expr, ".");
1707                         strcat(expr, flags_str);
1708                 }
1709         }
1710 }
1711
1712 static char *expr_str(struct hist_field *field, unsigned int level)
1713 {
1714         char *expr;
1715
1716         if (level > 1)
1717                 return NULL;
1718
1719         expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
1720         if (!expr)
1721                 return NULL;
1722
1723         if (!field->operands[0]) {
1724                 expr_field_str(field, expr);
1725                 return expr;
1726         }
1727
1728         if (field->operator == FIELD_OP_UNARY_MINUS) {
1729                 char *subexpr;
1730
1731                 strcat(expr, "-(");
1732                 subexpr = expr_str(field->operands[0], ++level);
1733                 if (!subexpr) {
1734                         kfree(expr);
1735                         return NULL;
1736                 }
1737                 strcat(expr, subexpr);
1738                 strcat(expr, ")");
1739
1740                 kfree(subexpr);
1741
1742                 return expr;
1743         }
1744
1745         expr_field_str(field->operands[0], expr);
1746
1747         switch (field->operator) {
1748         case FIELD_OP_MINUS:
1749                 strcat(expr, "-");
1750                 break;
1751         case FIELD_OP_PLUS:
1752                 strcat(expr, "+");
1753                 break;
1754         case FIELD_OP_DIV:
1755                 strcat(expr, "/");
1756                 break;
1757         case FIELD_OP_MULT:
1758                 strcat(expr, "*");
1759                 break;
1760         default:
1761                 kfree(expr);
1762                 return NULL;
1763         }
1764
1765         expr_field_str(field->operands[1], expr);
1766
1767         return expr;
1768 }
1769
1770 /*
1771  * If field_op != FIELD_OP_NONE, *sep points to the root operator
1772  * of the expression tree to be evaluated.
1773  */
1774 static int contains_operator(char *str, char **sep)
1775 {
1776         enum field_op_id field_op = FIELD_OP_NONE;
1777         char *minus_op, *plus_op, *div_op, *mult_op;
1778
1779
1780         /*
1781          * Report the last occurrence of the operators first, so that the
1782          * expression is evaluated left to right. This is important since
1783          * subtraction and division are not associative.
1784          *
1785          *      e.g
1786          *              64/8/4/2 is 1, i.e 64/8/4/2 = ((64/8)/4)/2
1787          *              14-7-5-2 is 0, i.e 14-7-5-2 = ((14-7)-5)-2
1788          */
1789
1790         /*
1791          * First, find lower precedence addition and subtraction
1792          * since the expression will be evaluated recursively.
1793          */
1794         minus_op = strrchr(str, '-');
1795         if (minus_op) {
1796                 /*
1797                  * Unary minus is not supported in sub-expressions. If
1798                  * present, it is always the next root operator.
1799                  */
1800                 if (minus_op == str) {
1801                         field_op = FIELD_OP_UNARY_MINUS;
1802                         goto out;
1803                 }
1804
1805                 field_op = FIELD_OP_MINUS;
1806         }
1807
1808         plus_op = strrchr(str, '+');
1809         if (plus_op || minus_op) {
1810                 /*
1811                  * For operators of the same precedence use to rightmost as the
1812                  * root, so that the expression is evaluated left to right.
1813                  */
1814                 if (plus_op > minus_op)
1815                         field_op = FIELD_OP_PLUS;
1816                 goto out;
1817         }
1818
1819         /*
1820          * Multiplication and division have higher precedence than addition and
1821          * subtraction.
1822          */
1823         div_op = strrchr(str, '/');
1824         if (div_op)
1825                 field_op = FIELD_OP_DIV;
1826
1827         mult_op = strrchr(str, '*');
1828         /*
1829          * For operators of the same precedence use to rightmost as the
1830          * root, so that the expression is evaluated left to right.
1831          */
1832         if (mult_op > div_op)
1833                 field_op = FIELD_OP_MULT;
1834
1835 out:
1836         if (sep) {
1837                 switch (field_op) {
1838                 case FIELD_OP_UNARY_MINUS:
1839                 case FIELD_OP_MINUS:
1840                         *sep = minus_op;
1841                         break;
1842                 case FIELD_OP_PLUS:
1843                         *sep = plus_op;
1844                         break;
1845                 case FIELD_OP_DIV:
1846                         *sep = div_op;
1847                         break;
1848                 case FIELD_OP_MULT:
1849                         *sep = mult_op;
1850                         break;
1851                 case FIELD_OP_NONE:
1852                 default:
1853                         *sep = NULL;
1854                         break;
1855                 }
1856         }
1857
1858         return field_op;
1859 }
1860
1861 static void get_hist_field(struct hist_field *hist_field)
1862 {
1863         hist_field->ref++;
1864 }
1865
1866 static void __destroy_hist_field(struct hist_field *hist_field)
1867 {
1868         if (--hist_field->ref > 1)
1869                 return;
1870
1871         kfree(hist_field->var.name);
1872         kfree(hist_field->name);
1873
1874         /* Can likely be a const */
1875         kfree_const(hist_field->type);
1876
1877         kfree(hist_field->system);
1878         kfree(hist_field->event_name);
1879
1880         kfree(hist_field);
1881 }
1882
1883 static void destroy_hist_field(struct hist_field *hist_field,
1884                                unsigned int level)
1885 {
1886         unsigned int i;
1887
1888         if (level > 3)
1889                 return;
1890
1891         if (!hist_field)
1892                 return;
1893
1894         if (hist_field->flags & HIST_FIELD_FL_VAR_REF)
1895                 return; /* var refs will be destroyed separately */
1896
1897         for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
1898                 destroy_hist_field(hist_field->operands[i], level + 1);
1899
1900         __destroy_hist_field(hist_field);
1901 }
1902
1903 static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
1904                                             struct ftrace_event_field *field,
1905                                             unsigned long flags,
1906                                             char *var_name)
1907 {
1908         struct hist_field *hist_field;
1909
1910         if (field && is_function_field(field))
1911                 return NULL;
1912
1913         hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
1914         if (!hist_field)
1915                 return NULL;
1916
1917         hist_field->ref = 1;
1918
1919         hist_field->hist_data = hist_data;
1920
1921         if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
1922                 goto out; /* caller will populate */
1923
1924         if (flags & HIST_FIELD_FL_VAR_REF) {
1925                 hist_field->fn = hist_field_var_ref;
1926                 goto out;
1927         }
1928
1929         if (flags & HIST_FIELD_FL_HITCOUNT) {
1930                 hist_field->fn = hist_field_counter;
1931                 hist_field->size = sizeof(u64);
1932                 hist_field->type = "u64";
1933                 goto out;
1934         }
1935
1936         if (flags & HIST_FIELD_FL_CONST) {
1937                 hist_field->fn = hist_field_const;
1938                 hist_field->size = sizeof(u64);
1939                 hist_field->type = kstrdup("u64", GFP_KERNEL);
1940                 if (!hist_field->type)
1941                         goto free;
1942                 goto out;
1943         }
1944
1945         if (flags & HIST_FIELD_FL_STACKTRACE) {
1946                 hist_field->fn = hist_field_none;
1947                 goto out;
1948         }
1949
1950         if (flags & (HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET)) {
1951                 unsigned long fl = flags & ~(HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET);
1952                 hist_field->fn = flags & HIST_FIELD_FL_LOG2 ? hist_field_log2 :
1953                         hist_field_bucket;
1954                 hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
1955                 hist_field->size = hist_field->operands[0]->size;
1956                 hist_field->type = kstrdup_const(hist_field->operands[0]->type, GFP_KERNEL);
1957                 if (!hist_field->type)
1958                         goto free;
1959                 goto out;
1960         }
1961
1962         if (flags & HIST_FIELD_FL_TIMESTAMP) {
1963                 hist_field->fn = hist_field_timestamp;
1964                 hist_field->size = sizeof(u64);
1965                 hist_field->type = "u64";
1966                 goto out;
1967         }
1968
1969         if (flags & HIST_FIELD_FL_CPU) {
1970                 hist_field->fn = hist_field_cpu;
1971                 hist_field->size = sizeof(int);
1972                 hist_field->type = "unsigned int";
1973                 goto out;
1974         }
1975
1976         if (WARN_ON_ONCE(!field))
1977                 goto out;
1978
1979         /* Pointers to strings are just pointers and dangerous to dereference */
1980         if (is_string_field(field) &&
1981             (field->filter_type != FILTER_PTR_STRING)) {
1982                 flags |= HIST_FIELD_FL_STRING;
1983
1984                 hist_field->size = MAX_FILTER_STR_VAL;
1985                 hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
1986                 if (!hist_field->type)
1987                         goto free;
1988
1989                 if (field->filter_type == FILTER_STATIC_STRING) {
1990                         hist_field->fn = hist_field_string;
1991                         hist_field->size = field->size;
1992                 } else if (field->filter_type == FILTER_DYN_STRING) {
1993                         hist_field->fn = hist_field_dynstring;
1994                 } else if (field->filter_type == FILTER_RDYN_STRING)
1995                         hist_field->fn = hist_field_reldynstring;
1996                 else
1997                         hist_field->fn = hist_field_pstring;
1998         } else {
1999                 hist_field->size = field->size;
2000                 hist_field->is_signed = field->is_signed;
2001                 hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
2002                 if (!hist_field->type)
2003                         goto free;
2004
2005                 hist_field->fn = select_value_fn(field->size,
2006                                                  field->is_signed);
2007                 if (!hist_field->fn) {
2008                         destroy_hist_field(hist_field, 0);
2009                         return NULL;
2010                 }
2011         }
2012  out:
2013         hist_field->field = field;
2014         hist_field->flags = flags;
2015
2016         if (var_name) {
2017                 hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
2018                 if (!hist_field->var.name)
2019                         goto free;
2020         }
2021
2022         return hist_field;
2023  free:
2024         destroy_hist_field(hist_field, 0);
2025         return NULL;
2026 }
2027
2028 static void destroy_hist_fields(struct hist_trigger_data *hist_data)
2029 {
2030         unsigned int i;
2031
2032         for (i = 0; i < HIST_FIELDS_MAX; i++) {
2033                 if (hist_data->fields[i]) {
2034                         destroy_hist_field(hist_data->fields[i], 0);
2035                         hist_data->fields[i] = NULL;
2036                 }
2037         }
2038
2039         for (i = 0; i < hist_data->n_var_refs; i++) {
2040                 WARN_ON(!(hist_data->var_refs[i]->flags & HIST_FIELD_FL_VAR_REF));
2041                 __destroy_hist_field(hist_data->var_refs[i]);
2042                 hist_data->var_refs[i] = NULL;
2043         }
2044 }
2045
2046 static int init_var_ref(struct hist_field *ref_field,
2047                         struct hist_field *var_field,
2048                         char *system, char *event_name)
2049 {
2050         int err = 0;
2051
2052         ref_field->var.idx = var_field->var.idx;
2053         ref_field->var.hist_data = var_field->hist_data;
2054         ref_field->size = var_field->size;
2055         ref_field->is_signed = var_field->is_signed;
2056         ref_field->flags |= var_field->flags &
2057                 (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2058
2059         if (system) {
2060                 ref_field->system = kstrdup(system, GFP_KERNEL);
2061                 if (!ref_field->system)
2062                         return -ENOMEM;
2063         }
2064
2065         if (event_name) {
2066                 ref_field->event_name = kstrdup(event_name, GFP_KERNEL);
2067                 if (!ref_field->event_name) {
2068                         err = -ENOMEM;
2069                         goto free;
2070                 }
2071         }
2072
2073         if (var_field->var.name) {
2074                 ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
2075                 if (!ref_field->name) {
2076                         err = -ENOMEM;
2077                         goto free;
2078                 }
2079         } else if (var_field->name) {
2080                 ref_field->name = kstrdup(var_field->name, GFP_KERNEL);
2081                 if (!ref_field->name) {
2082                         err = -ENOMEM;
2083                         goto free;
2084                 }
2085         }
2086
2087         ref_field->type = kstrdup_const(var_field->type, GFP_KERNEL);
2088         if (!ref_field->type) {
2089                 err = -ENOMEM;
2090                 goto free;
2091         }
2092  out:
2093         return err;
2094  free:
2095         kfree(ref_field->system);
2096         kfree(ref_field->event_name);
2097         kfree(ref_field->name);
2098
2099         goto out;
2100 }
2101
2102 static int find_var_ref_idx(struct hist_trigger_data *hist_data,
2103                             struct hist_field *var_field)
2104 {
2105         struct hist_field *ref_field;
2106         int i;
2107
2108         for (i = 0; i < hist_data->n_var_refs; i++) {
2109                 ref_field = hist_data->var_refs[i];
2110                 if (ref_field->var.idx == var_field->var.idx &&
2111                     ref_field->var.hist_data == var_field->hist_data)
2112                         return i;
2113         }
2114
2115         return -ENOENT;
2116 }
2117
2118 /**
2119  * create_var_ref - Create a variable reference and attach it to trigger
2120  * @hist_data: The trigger that will be referencing the variable
2121  * @var_field: The VAR field to create a reference to
2122  * @system: The optional system string
2123  * @event_name: The optional event_name string
2124  *
2125  * Given a variable hist_field, create a VAR_REF hist_field that
2126  * represents a reference to it.
2127  *
2128  * This function also adds the reference to the trigger that
2129  * now references the variable.
2130  *
2131  * Return: The VAR_REF field if successful, NULL if not
2132  */
2133 static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
2134                                          struct hist_field *var_field,
2135                                          char *system, char *event_name)
2136 {
2137         unsigned long flags = HIST_FIELD_FL_VAR_REF;
2138         struct hist_field *ref_field;
2139         int i;
2140
2141         /* Check if the variable already exists */
2142         for (i = 0; i < hist_data->n_var_refs; i++) {
2143                 ref_field = hist_data->var_refs[i];
2144                 if (ref_field->var.idx == var_field->var.idx &&
2145                     ref_field->var.hist_data == var_field->hist_data) {
2146                         get_hist_field(ref_field);
2147                         return ref_field;
2148                 }
2149         }
2150
2151         ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
2152         if (ref_field) {
2153                 if (init_var_ref(ref_field, var_field, system, event_name)) {
2154                         destroy_hist_field(ref_field, 0);
2155                         return NULL;
2156                 }
2157
2158                 hist_data->var_refs[hist_data->n_var_refs] = ref_field;
2159                 ref_field->var_ref_idx = hist_data->n_var_refs++;
2160         }
2161
2162         return ref_field;
2163 }
2164
2165 static bool is_var_ref(char *var_name)
2166 {
2167         if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
2168                 return false;
2169
2170         return true;
2171 }
2172
2173 static char *field_name_from_var(struct hist_trigger_data *hist_data,
2174                                  char *var_name)
2175 {
2176         char *name, *field;
2177         unsigned int i;
2178
2179         for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
2180                 name = hist_data->attrs->var_defs.name[i];
2181
2182                 if (strcmp(var_name, name) == 0) {
2183                         field = hist_data->attrs->var_defs.expr[i];
2184                         if (contains_operator(field, NULL) || is_var_ref(field))
2185                                 continue;
2186                         return field;
2187                 }
2188         }
2189
2190         return NULL;
2191 }
2192
2193 static char *local_field_var_ref(struct hist_trigger_data *hist_data,
2194                                  char *system, char *event_name,
2195                                  char *var_name)
2196 {
2197         struct trace_event_call *call;
2198
2199         if (system && event_name) {
2200                 call = hist_data->event_file->event_call;
2201
2202                 if (strcmp(system, call->class->system) != 0)
2203                         return NULL;
2204
2205                 if (strcmp(event_name, trace_event_name(call)) != 0)
2206                         return NULL;
2207         }
2208
2209         if (!!system != !!event_name)
2210                 return NULL;
2211
2212         if (!is_var_ref(var_name))
2213                 return NULL;
2214
2215         var_name++;
2216
2217         return field_name_from_var(hist_data, var_name);
2218 }
2219
2220 static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
2221                                         char *system, char *event_name,
2222                                         char *var_name)
2223 {
2224         struct hist_field *var_field = NULL, *ref_field = NULL;
2225         struct trace_array *tr = hist_data->event_file->tr;
2226
2227         if (!is_var_ref(var_name))
2228                 return NULL;
2229
2230         var_name++;
2231
2232         var_field = find_event_var(hist_data, system, event_name, var_name);
2233         if (var_field)
2234                 ref_field = create_var_ref(hist_data, var_field,
2235                                            system, event_name);
2236
2237         if (!ref_field)
2238                 hist_err(tr, HIST_ERR_VAR_NOT_FOUND, errpos(var_name));
2239
2240         return ref_field;
2241 }
2242
2243 static struct ftrace_event_field *
2244 parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
2245             char *field_str, unsigned long *flags, unsigned long *buckets)
2246 {
2247         struct ftrace_event_field *field = NULL;
2248         char *field_name, *modifier, *str;
2249         struct trace_array *tr = file->tr;
2250
2251         modifier = str = kstrdup(field_str, GFP_KERNEL);
2252         if (!modifier)
2253                 return ERR_PTR(-ENOMEM);
2254
2255         field_name = strsep(&modifier, ".");
2256         if (modifier) {
2257                 if (strcmp(modifier, "hex") == 0)
2258                         *flags |= HIST_FIELD_FL_HEX;
2259                 else if (strcmp(modifier, "sym") == 0)
2260                         *flags |= HIST_FIELD_FL_SYM;
2261                 /*
2262                  * 'sym-offset' occurrences in the trigger string are modified
2263                  * to 'symXoffset' to simplify arithmetic expression parsing.
2264                  */
2265                 else if (strcmp(modifier, "symXoffset") == 0)
2266                         *flags |= HIST_FIELD_FL_SYM_OFFSET;
2267                 else if ((strcmp(modifier, "execname") == 0) &&
2268                          (strcmp(field_name, "common_pid") == 0))
2269                         *flags |= HIST_FIELD_FL_EXECNAME;
2270                 else if (strcmp(modifier, "syscall") == 0)
2271                         *flags |= HIST_FIELD_FL_SYSCALL;
2272                 else if (strcmp(modifier, "log2") == 0)
2273                         *flags |= HIST_FIELD_FL_LOG2;
2274                 else if (strcmp(modifier, "usecs") == 0)
2275                         *flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
2276                 else if (strncmp(modifier, "bucket", 6) == 0) {
2277                         int ret;
2278
2279                         modifier += 6;
2280
2281                         if (*modifier == 's')
2282                                 modifier++;
2283                         if (*modifier != '=')
2284                                 goto error;
2285                         modifier++;
2286                         ret = kstrtoul(modifier, 0, buckets);
2287                         if (ret || !(*buckets))
2288                                 goto error;
2289                         *flags |= HIST_FIELD_FL_BUCKET;
2290                 } else {
2291  error:
2292                         hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
2293                         field = ERR_PTR(-EINVAL);
2294                         goto out;
2295                 }
2296         }
2297
2298         if (strcmp(field_name, "common_timestamp") == 0) {
2299                 *flags |= HIST_FIELD_FL_TIMESTAMP;
2300                 hist_data->enable_timestamps = true;
2301                 if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2302                         hist_data->attrs->ts_in_usecs = true;
2303         } else if (strcmp(field_name, "common_cpu") == 0)
2304                 *flags |= HIST_FIELD_FL_CPU;
2305         else {
2306                 field = trace_find_event_field(file->event_call, field_name);
2307                 if (!field || !field->size) {
2308                         /*
2309                          * For backward compatibility, if field_name
2310                          * was "cpu", then we treat this the same as
2311                          * common_cpu. This also works for "CPU".
2312                          */
2313                         if (field && field->filter_type == FILTER_CPU) {
2314                                 *flags |= HIST_FIELD_FL_CPU;
2315                         } else {
2316                                 hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,
2317                                          errpos(field_name));
2318                                 field = ERR_PTR(-EINVAL);
2319                                 goto out;
2320                         }
2321                 }
2322         }
2323  out:
2324         kfree(str);
2325
2326         return field;
2327 }
2328
2329 static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
2330                                        struct hist_field *var_ref,
2331                                        char *var_name)
2332 {
2333         struct hist_field *alias = NULL;
2334         unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;
2335
2336         alias = create_hist_field(hist_data, NULL, flags, var_name);
2337         if (!alias)
2338                 return NULL;
2339
2340         alias->fn = var_ref->fn;
2341         alias->operands[0] = var_ref;
2342
2343         if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
2344                 destroy_hist_field(alias, 0);
2345                 return NULL;
2346         }
2347
2348         alias->var_ref_idx = var_ref->var_ref_idx;
2349
2350         return alias;
2351 }
2352
2353 static struct hist_field *parse_const(struct hist_trigger_data *hist_data,
2354                                       char *str, char *var_name,
2355                                       unsigned long *flags)
2356 {
2357         struct trace_array *tr = hist_data->event_file->tr;
2358         struct hist_field *field = NULL;
2359         u64 constant;
2360
2361         if (kstrtoull(str, 0, &constant)) {
2362                 hist_err(tr, HIST_ERR_EXPECT_NUMBER, errpos(str));
2363                 return NULL;
2364         }
2365
2366         *flags |= HIST_FIELD_FL_CONST;
2367         field = create_hist_field(hist_data, NULL, *flags, var_name);
2368         if (!field)
2369                 return NULL;
2370
2371         field->constant = constant;
2372
2373         return field;
2374 }
2375
2376 static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
2377                                      struct trace_event_file *file, char *str,
2378                                      unsigned long *flags, char *var_name)
2379 {
2380         char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
2381         struct ftrace_event_field *field = NULL;
2382         struct hist_field *hist_field = NULL;
2383         unsigned long buckets = 0;
2384         int ret = 0;
2385
2386         if (isdigit(str[0])) {
2387                 hist_field = parse_const(hist_data, str, var_name, flags);
2388                 if (!hist_field) {
2389                         ret = -EINVAL;
2390                         goto out;
2391                 }
2392                 return hist_field;
2393         }
2394
2395         s = strchr(str, '.');
2396         if (s) {
2397                 s = strchr(++s, '.');
2398                 if (s) {
2399                         ref_system = strsep(&str, ".");
2400                         if (!str) {
2401                                 ret = -EINVAL;
2402                                 goto out;
2403                         }
2404                         ref_event = strsep(&str, ".");
2405                         if (!str) {
2406                                 ret = -EINVAL;
2407                                 goto out;
2408                         }
2409                         ref_var = str;
2410                 }
2411         }
2412
2413         s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
2414         if (!s) {
2415                 hist_field = parse_var_ref(hist_data, ref_system,
2416                                            ref_event, ref_var);
2417                 if (hist_field) {
2418                         if (var_name) {
2419                                 hist_field = create_alias(hist_data, hist_field, var_name);
2420                                 if (!hist_field) {
2421                                         ret = -ENOMEM;
2422                                         goto out;
2423                                 }
2424                         }
2425                         return hist_field;
2426                 }
2427         } else
2428                 str = s;
2429
2430         field = parse_field(hist_data, file, str, flags, &buckets);
2431         if (IS_ERR(field)) {
2432                 ret = PTR_ERR(field);
2433                 goto out;
2434         }
2435
2436         hist_field = create_hist_field(hist_data, field, *flags, var_name);
2437         if (!hist_field) {
2438                 ret = -ENOMEM;
2439                 goto out;
2440         }
2441         hist_field->buckets = buckets;
2442
2443         return hist_field;
2444  out:
2445         return ERR_PTR(ret);
2446 }
2447
2448 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2449                                      struct trace_event_file *file,
2450                                      char *str, unsigned long flags,
2451                                      char *var_name, unsigned int *n_subexprs);
2452
2453 static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
2454                                       struct trace_event_file *file,
2455                                       char *str, unsigned long flags,
2456                                       char *var_name, unsigned int *n_subexprs)
2457 {
2458         struct hist_field *operand1, *expr = NULL;
2459         unsigned long operand_flags;
2460         int ret = 0;
2461         char *s;
2462
2463         /* Unary minus operator, increment n_subexprs */
2464         ++*n_subexprs;
2465
2466         /* we support only -(xxx) i.e. explicit parens required */
2467
2468         if (*n_subexprs > 3) {
2469                 hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2470                 ret = -EINVAL;
2471                 goto free;
2472         }
2473
2474         str++; /* skip leading '-' */
2475
2476         s = strchr(str, '(');
2477         if (s)
2478                 str++;
2479         else {
2480                 ret = -EINVAL;
2481                 goto free;
2482         }
2483
2484         s = strrchr(str, ')');
2485         if (s) {
2486                  /* unary minus not supported in sub-expressions */
2487                 if (*(s+1) != '\0') {
2488                         hist_err(file->tr, HIST_ERR_UNARY_MINUS_SUBEXPR,
2489                                  errpos(str));
2490                         ret = -EINVAL;
2491                         goto free;
2492                 }
2493                 *s = '\0';
2494         }
2495         else {
2496                 ret = -EINVAL; /* no closing ')' */
2497                 goto free;
2498         }
2499
2500         flags |= HIST_FIELD_FL_EXPR;
2501         expr = create_hist_field(hist_data, NULL, flags, var_name);
2502         if (!expr) {
2503                 ret = -ENOMEM;
2504                 goto free;
2505         }
2506
2507         operand_flags = 0;
2508         operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2509         if (IS_ERR(operand1)) {
2510                 ret = PTR_ERR(operand1);
2511                 goto free;
2512         }
2513         if (operand1->flags & HIST_FIELD_FL_STRING) {
2514                 /* String type can not be the operand of unary operator. */
2515                 hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2516                 destroy_hist_field(operand1, 0);
2517                 ret = -EINVAL;
2518                 goto free;
2519         }
2520
2521         expr->flags |= operand1->flags &
2522                 (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2523         expr->fn = hist_field_unary_minus;
2524         expr->operands[0] = operand1;
2525         expr->size = operand1->size;
2526         expr->is_signed = operand1->is_signed;
2527         expr->operator = FIELD_OP_UNARY_MINUS;
2528         expr->name = expr_str(expr, 0);
2529         expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2530         if (!expr->type) {
2531                 ret = -ENOMEM;
2532                 goto free;
2533         }
2534
2535         return expr;
2536  free:
2537         destroy_hist_field(expr, 0);
2538         return ERR_PTR(ret);
2539 }
2540
2541 /*
2542  * If the operands are var refs, return pointers the
2543  * variable(s) referenced in var1 and var2, else NULL.
2544  */
2545 static int check_expr_operands(struct trace_array *tr,
2546                                struct hist_field *operand1,
2547                                struct hist_field *operand2,
2548                                struct hist_field **var1,
2549                                struct hist_field **var2)
2550 {
2551         unsigned long operand1_flags = operand1->flags;
2552         unsigned long operand2_flags = operand2->flags;
2553
2554         if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
2555             (operand1_flags & HIST_FIELD_FL_ALIAS)) {
2556                 struct hist_field *var;
2557
2558                 var = find_var_field(operand1->var.hist_data, operand1->name);
2559                 if (!var)
2560                         return -EINVAL;
2561                 operand1_flags = var->flags;
2562                 *var1 = var;
2563         }
2564
2565         if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
2566             (operand2_flags & HIST_FIELD_FL_ALIAS)) {
2567                 struct hist_field *var;
2568
2569                 var = find_var_field(operand2->var.hist_data, operand2->name);
2570                 if (!var)
2571                         return -EINVAL;
2572                 operand2_flags = var->flags;
2573                 *var2 = var;
2574         }
2575
2576         if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
2577             (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
2578                 hist_err(tr, HIST_ERR_TIMESTAMP_MISMATCH, 0);
2579                 return -EINVAL;
2580         }
2581
2582         return 0;
2583 }
2584
2585 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2586                                      struct trace_event_file *file,
2587                                      char *str, unsigned long flags,
2588                                      char *var_name, unsigned int *n_subexprs)
2589 {
2590         struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
2591         struct hist_field *var1 = NULL, *var2 = NULL;
2592         unsigned long operand_flags, operand2_flags;
2593         int field_op, ret = -EINVAL;
2594         char *sep, *operand1_str;
2595         hist_field_fn_t op_fn;
2596         bool combine_consts;
2597
2598         if (*n_subexprs > 3) {
2599                 hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2600                 return ERR_PTR(-EINVAL);
2601         }
2602
2603         field_op = contains_operator(str, &sep);
2604
2605         if (field_op == FIELD_OP_NONE)
2606                 return parse_atom(hist_data, file, str, &flags, var_name);
2607
2608         if (field_op == FIELD_OP_UNARY_MINUS)
2609                 return parse_unary(hist_data, file, str, flags, var_name, n_subexprs);
2610
2611         /* Binary operator found, increment n_subexprs */
2612         ++*n_subexprs;
2613
2614         /* Split the expression string at the root operator */
2615         if (!sep)
2616                 return ERR_PTR(-EINVAL);
2617
2618         *sep = '\0';
2619         operand1_str = str;
2620         str = sep+1;
2621
2622         /* Binary operator requires both operands */
2623         if (*operand1_str == '\0' || *str == '\0')
2624                 return ERR_PTR(-EINVAL);
2625
2626         operand_flags = 0;
2627
2628         /* LHS of string is an expression e.g. a+b in a+b+c */
2629         operand1 = parse_expr(hist_data, file, operand1_str, operand_flags, NULL, n_subexprs);
2630         if (IS_ERR(operand1))
2631                 return ERR_CAST(operand1);
2632
2633         if (operand1->flags & HIST_FIELD_FL_STRING) {
2634                 hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(operand1_str));
2635                 ret = -EINVAL;
2636                 goto free_op1;
2637         }
2638
2639         /* RHS of string is another expression e.g. c in a+b+c */
2640         operand_flags = 0;
2641         operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2642         if (IS_ERR(operand2)) {
2643                 ret = PTR_ERR(operand2);
2644                 goto free_op1;
2645         }
2646         if (operand2->flags & HIST_FIELD_FL_STRING) {
2647                 hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2648                 ret = -EINVAL;
2649                 goto free_operands;
2650         }
2651
2652         switch (field_op) {
2653         case FIELD_OP_MINUS:
2654                 op_fn = hist_field_minus;
2655                 break;
2656         case FIELD_OP_PLUS:
2657                 op_fn = hist_field_plus;
2658                 break;
2659         case FIELD_OP_DIV:
2660                 op_fn = hist_field_div;
2661                 break;
2662         case FIELD_OP_MULT:
2663                 op_fn = hist_field_mult;
2664                 break;
2665         default:
2666                 ret = -EINVAL;
2667                 goto free_operands;
2668         }
2669
2670         ret = check_expr_operands(file->tr, operand1, operand2, &var1, &var2);
2671         if (ret)
2672                 goto free_operands;
2673
2674         operand_flags = var1 ? var1->flags : operand1->flags;
2675         operand2_flags = var2 ? var2->flags : operand2->flags;
2676
2677         /*
2678          * If both operands are constant, the expression can be
2679          * collapsed to a single constant.
2680          */
2681         combine_consts = operand_flags & operand2_flags & HIST_FIELD_FL_CONST;
2682
2683         flags |= combine_consts ? HIST_FIELD_FL_CONST : HIST_FIELD_FL_EXPR;
2684
2685         flags |= operand1->flags &
2686                 (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2687
2688         expr = create_hist_field(hist_data, NULL, flags, var_name);
2689         if (!expr) {
2690                 ret = -ENOMEM;
2691                 goto free_operands;
2692         }
2693
2694         operand1->read_once = true;
2695         operand2->read_once = true;
2696
2697         /* The operands are now owned and free'd by 'expr' */
2698         expr->operands[0] = operand1;
2699         expr->operands[1] = operand2;
2700
2701         if (field_op == FIELD_OP_DIV &&
2702                         operand2_flags & HIST_FIELD_FL_CONST) {
2703                 u64 divisor = var2 ? var2->constant : operand2->constant;
2704
2705                 if (!divisor) {
2706                         hist_err(file->tr, HIST_ERR_DIVISION_BY_ZERO, errpos(str));
2707                         ret = -EDOM;
2708                         goto free_expr;
2709                 }
2710
2711                 /*
2712                  * Copy the divisor here so we don't have to look it up
2713                  * later if this is a var ref
2714                  */
2715                 operand2->constant = divisor;
2716                 op_fn = hist_field_get_div_fn(operand2);
2717         }
2718
2719         if (combine_consts) {
2720                 if (var1)
2721                         expr->operands[0] = var1;
2722                 if (var2)
2723                         expr->operands[1] = var2;
2724
2725                 expr->constant = op_fn(expr, NULL, NULL, NULL, NULL);
2726
2727                 expr->operands[0] = NULL;
2728                 expr->operands[1] = NULL;
2729
2730                 /*
2731                  * var refs won't be destroyed immediately
2732                  * See: destroy_hist_field()
2733                  */
2734                 destroy_hist_field(operand2, 0);
2735                 destroy_hist_field(operand1, 0);
2736
2737                 expr->name = expr_str(expr, 0);
2738         } else {
2739                 expr->fn = op_fn;
2740
2741                 /* The operand sizes should be the same, so just pick one */
2742                 expr->size = operand1->size;
2743                 expr->is_signed = operand1->is_signed;
2744
2745                 expr->operator = field_op;
2746                 expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2747                 if (!expr->type) {
2748                         ret = -ENOMEM;
2749                         goto free_expr;
2750                 }
2751
2752                 expr->name = expr_str(expr, 0);
2753         }
2754
2755         return expr;
2756
2757 free_operands:
2758         destroy_hist_field(operand2, 0);
2759 free_op1:
2760         destroy_hist_field(operand1, 0);
2761         return ERR_PTR(ret);
2762
2763 free_expr:
2764         destroy_hist_field(expr, 0);
2765         return ERR_PTR(ret);
2766 }
2767
2768 static char *find_trigger_filter(struct hist_trigger_data *hist_data,
2769                                  struct trace_event_file *file)
2770 {
2771         struct event_trigger_data *test;
2772
2773         lockdep_assert_held(&event_mutex);
2774
2775         list_for_each_entry(test, &file->triggers, list) {
2776                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2777                         if (test->private_data == hist_data)
2778                                 return test->filter_str;
2779                 }
2780         }
2781
2782         return NULL;
2783 }
2784
2785 static struct event_command trigger_hist_cmd;
2786 static int event_hist_trigger_parse(struct event_command *cmd_ops,
2787                                     struct trace_event_file *file,
2788                                     char *glob, char *cmd, char *param);
2789
2790 static bool compatible_keys(struct hist_trigger_data *target_hist_data,
2791                             struct hist_trigger_data *hist_data,
2792                             unsigned int n_keys)
2793 {
2794         struct hist_field *target_hist_field, *hist_field;
2795         unsigned int n, i, j;
2796
2797         if (hist_data->n_fields - hist_data->n_vals != n_keys)
2798                 return false;
2799
2800         i = hist_data->n_vals;
2801         j = target_hist_data->n_vals;
2802
2803         for (n = 0; n < n_keys; n++) {
2804                 hist_field = hist_data->fields[i + n];
2805                 target_hist_field = target_hist_data->fields[j + n];
2806
2807                 if (strcmp(hist_field->type, target_hist_field->type) != 0)
2808                         return false;
2809                 if (hist_field->size != target_hist_field->size)
2810                         return false;
2811                 if (hist_field->is_signed != target_hist_field->is_signed)
2812                         return false;
2813         }
2814
2815         return true;
2816 }
2817
2818 static struct hist_trigger_data *
2819 find_compatible_hist(struct hist_trigger_data *target_hist_data,
2820                      struct trace_event_file *file)
2821 {
2822         struct hist_trigger_data *hist_data;
2823         struct event_trigger_data *test;
2824         unsigned int n_keys;
2825
2826         lockdep_assert_held(&event_mutex);
2827
2828         n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
2829
2830         list_for_each_entry(test, &file->triggers, list) {
2831                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2832                         hist_data = test->private_data;
2833
2834                         if (compatible_keys(target_hist_data, hist_data, n_keys))
2835                                 return hist_data;
2836                 }
2837         }
2838
2839         return NULL;
2840 }
2841
2842 static struct trace_event_file *event_file(struct trace_array *tr,
2843                                            char *system, char *event_name)
2844 {
2845         struct trace_event_file *file;
2846
2847         file = __find_event_file(tr, system, event_name);
2848         if (!file)
2849                 return ERR_PTR(-EINVAL);
2850
2851         return file;
2852 }
2853
2854 static struct hist_field *
2855 find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
2856                          char *system, char *event_name, char *field_name)
2857 {
2858         struct hist_field *event_var;
2859         char *synthetic_name;
2860
2861         synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2862         if (!synthetic_name)
2863                 return ERR_PTR(-ENOMEM);
2864
2865         strcpy(synthetic_name, "synthetic_");
2866         strcat(synthetic_name, field_name);
2867
2868         event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);
2869
2870         kfree(synthetic_name);
2871
2872         return event_var;
2873 }
2874
2875 /**
2876  * create_field_var_hist - Automatically create a histogram and var for a field
2877  * @target_hist_data: The target hist trigger
2878  * @subsys_name: Optional subsystem name
2879  * @event_name: Optional event name
2880  * @field_name: The name of the field (and the resulting variable)
2881  *
2882  * Hist trigger actions fetch data from variables, not directly from
2883  * events.  However, for convenience, users are allowed to directly
2884  * specify an event field in an action, which will be automatically
2885  * converted into a variable on their behalf.
2886  *
2887  * If a user specifies a field on an event that isn't the event the
2888  * histogram currently being defined (the target event histogram), the
2889  * only way that can be accomplished is if a new hist trigger is
2890  * created and the field variable defined on that.
2891  *
2892  * This function creates a new histogram compatible with the target
2893  * event (meaning a histogram with the same key as the target
2894  * histogram), and creates a variable for the specified field, but
2895  * with 'synthetic_' prepended to the variable name in order to avoid
2896  * collision with normal field variables.
2897  *
2898  * Return: The variable created for the field.
2899  */
2900 static struct hist_field *
2901 create_field_var_hist(struct hist_trigger_data *target_hist_data,
2902                       char *subsys_name, char *event_name, char *field_name)
2903 {
2904         struct trace_array *tr = target_hist_data->event_file->tr;
2905         struct hist_trigger_data *hist_data;
2906         unsigned int i, n, first = true;
2907         struct field_var_hist *var_hist;
2908         struct trace_event_file *file;
2909         struct hist_field *key_field;
2910         struct hist_field *event_var;
2911         char *saved_filter;
2912         char *cmd;
2913         int ret;
2914
2915         if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
2916                 hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
2917                 return ERR_PTR(-EINVAL);
2918         }
2919
2920         file = event_file(tr, subsys_name, event_name);
2921
2922         if (IS_ERR(file)) {
2923                 hist_err(tr, HIST_ERR_EVENT_FILE_NOT_FOUND, errpos(field_name));
2924                 ret = PTR_ERR(file);
2925                 return ERR_PTR(ret);
2926         }
2927
2928         /*
2929          * Look for a histogram compatible with target.  We'll use the
2930          * found histogram specification to create a new matching
2931          * histogram with our variable on it.  target_hist_data is not
2932          * yet a registered histogram so we can't use that.
2933          */
2934         hist_data = find_compatible_hist(target_hist_data, file);
2935         if (!hist_data) {
2936                 hist_err(tr, HIST_ERR_HIST_NOT_FOUND, errpos(field_name));
2937                 return ERR_PTR(-EINVAL);
2938         }
2939
2940         /* See if a synthetic field variable has already been created */
2941         event_var = find_synthetic_field_var(target_hist_data, subsys_name,
2942                                              event_name, field_name);
2943         if (!IS_ERR_OR_NULL(event_var))
2944                 return event_var;
2945
2946         var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
2947         if (!var_hist)
2948                 return ERR_PTR(-ENOMEM);
2949
2950         cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2951         if (!cmd) {
2952                 kfree(var_hist);
2953                 return ERR_PTR(-ENOMEM);
2954         }
2955
2956         /* Use the same keys as the compatible histogram */
2957         strcat(cmd, "keys=");
2958
2959         for_each_hist_key_field(i, hist_data) {
2960                 key_field = hist_data->fields[i];
2961                 if (!first)
2962                         strcat(cmd, ",");
2963                 strcat(cmd, key_field->field->name);
2964                 first = false;
2965         }
2966
2967         /* Create the synthetic field variable specification */
2968         strcat(cmd, ":synthetic_");
2969         strcat(cmd, field_name);
2970         strcat(cmd, "=");
2971         strcat(cmd, field_name);
2972
2973         /* Use the same filter as the compatible histogram */
2974         saved_filter = find_trigger_filter(hist_data, file);
2975         if (saved_filter) {
2976                 strcat(cmd, " if ");
2977                 strcat(cmd, saved_filter);
2978         }
2979
2980         var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
2981         if (!var_hist->cmd) {
2982                 kfree(cmd);
2983                 kfree(var_hist);
2984                 return ERR_PTR(-ENOMEM);
2985         }
2986
2987         /* Save the compatible histogram information */
2988         var_hist->hist_data = hist_data;
2989
2990         /* Create the new histogram with our variable */
2991         ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
2992                                        "", "hist", cmd);
2993         if (ret) {
2994                 kfree(cmd);
2995                 kfree(var_hist->cmd);
2996                 kfree(var_hist);
2997                 hist_err(tr, HIST_ERR_HIST_CREATE_FAIL, errpos(field_name));
2998                 return ERR_PTR(ret);
2999         }
3000
3001         kfree(cmd);
3002
3003         /* If we can't find the variable, something went wrong */
3004         event_var = find_synthetic_field_var(target_hist_data, subsys_name,
3005                                              event_name, field_name);
3006         if (IS_ERR_OR_NULL(event_var)) {
3007                 kfree(var_hist->cmd);
3008                 kfree(var_hist);
3009                 hist_err(tr, HIST_ERR_SYNTH_VAR_NOT_FOUND, errpos(field_name));
3010                 return ERR_PTR(-EINVAL);
3011         }
3012
3013         n = target_hist_data->n_field_var_hists;
3014         target_hist_data->field_var_hists[n] = var_hist;
3015         target_hist_data->n_field_var_hists++;
3016
3017         return event_var;
3018 }
3019
3020 static struct hist_field *
3021 find_target_event_var(struct hist_trigger_data *hist_data,
3022                       char *subsys_name, char *event_name, char *var_name)
3023 {
3024         struct trace_event_file *file = hist_data->event_file;
3025         struct hist_field *hist_field = NULL;
3026
3027         if (subsys_name) {
3028                 struct trace_event_call *call;
3029
3030                 if (!event_name)
3031                         return NULL;
3032
3033                 call = file->event_call;
3034
3035                 if (strcmp(subsys_name, call->class->system) != 0)
3036                         return NULL;
3037
3038                 if (strcmp(event_name, trace_event_name(call)) != 0)
3039                         return NULL;
3040         }
3041
3042         hist_field = find_var_field(hist_data, var_name);
3043
3044         return hist_field;
3045 }
3046
3047 static inline void __update_field_vars(struct tracing_map_elt *elt,
3048                                        struct trace_buffer *buffer,
3049                                        struct ring_buffer_event *rbe,
3050                                        void *rec,
3051                                        struct field_var **field_vars,
3052                                        unsigned int n_field_vars,
3053                                        unsigned int field_var_str_start)
3054 {
3055         struct hist_elt_data *elt_data = elt->private_data;
3056         unsigned int i, j, var_idx;
3057         u64 var_val;
3058
3059         for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
3060                 struct field_var *field_var = field_vars[i];
3061                 struct hist_field *var = field_var->var;
3062                 struct hist_field *val = field_var->val;
3063
3064                 var_val = val->fn(val, elt, buffer, rbe, rec);
3065                 var_idx = var->var.idx;
3066
3067                 if (val->flags & HIST_FIELD_FL_STRING) {
3068                         char *str = elt_data->field_var_str[j++];
3069                         char *val_str = (char *)(uintptr_t)var_val;
3070                         unsigned int size;
3071
3072                         size = min(val->size, STR_VAR_LEN_MAX);
3073                         strscpy(str, val_str, size);
3074                         var_val = (u64)(uintptr_t)str;
3075                 }
3076                 tracing_map_set_var(elt, var_idx, var_val);
3077         }
3078 }
3079
3080 static void update_field_vars(struct hist_trigger_data *hist_data,
3081                               struct tracing_map_elt *elt,
3082                               struct trace_buffer *buffer,
3083                               struct ring_buffer_event *rbe,
3084                               void *rec)
3085 {
3086         __update_field_vars(elt, buffer, rbe, rec, hist_data->field_vars,
3087                             hist_data->n_field_vars, 0);
3088 }
3089
3090 static void save_track_data_vars(struct hist_trigger_data *hist_data,
3091                                  struct tracing_map_elt *elt,
3092                                  struct trace_buffer *buffer,  void *rec,
3093                                  struct ring_buffer_event *rbe, void *key,
3094                                  struct action_data *data, u64 *var_ref_vals)
3095 {
3096         __update_field_vars(elt, buffer, rbe, rec, hist_data->save_vars,
3097                             hist_data->n_save_vars, hist_data->n_field_var_str);
3098 }
3099
3100 static struct hist_field *create_var(struct hist_trigger_data *hist_data,
3101                                      struct trace_event_file *file,
3102                                      char *name, int size, const char *type)
3103 {
3104         struct hist_field *var;
3105         int idx;
3106
3107         if (find_var(hist_data, file, name) && !hist_data->remove) {
3108                 var = ERR_PTR(-EINVAL);
3109                 goto out;
3110         }
3111
3112         var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
3113         if (!var) {
3114                 var = ERR_PTR(-ENOMEM);
3115                 goto out;
3116         }
3117
3118         idx = tracing_map_add_var(hist_data->map);
3119         if (idx < 0) {
3120                 kfree(var);
3121                 var = ERR_PTR(-EINVAL);
3122                 goto out;
3123         }
3124
3125         var->ref = 1;
3126         var->flags = HIST_FIELD_FL_VAR;
3127         var->var.idx = idx;
3128         var->var.hist_data = var->hist_data = hist_data;
3129         var->size = size;
3130         var->var.name = kstrdup(name, GFP_KERNEL);
3131         var->type = kstrdup_const(type, GFP_KERNEL);
3132         if (!var->var.name || !var->type) {
3133                 kfree_const(var->type);
3134                 kfree(var->var.name);
3135                 kfree(var);
3136                 var = ERR_PTR(-ENOMEM);
3137         }
3138  out:
3139         return var;
3140 }
3141
3142 static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
3143                                           struct trace_event_file *file,
3144                                           char *field_name)
3145 {
3146         struct hist_field *val = NULL, *var = NULL;
3147         unsigned long flags = HIST_FIELD_FL_VAR;
3148         struct trace_array *tr = file->tr;
3149         struct field_var *field_var;
3150         int ret = 0;
3151
3152         if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
3153                 hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
3154                 ret = -EINVAL;
3155                 goto err;
3156         }
3157
3158         val = parse_atom(hist_data, file, field_name, &flags, NULL);
3159         if (IS_ERR(val)) {
3160                 hist_err(tr, HIST_ERR_FIELD_VAR_PARSE_FAIL, errpos(field_name));
3161                 ret = PTR_ERR(val);
3162                 goto err;
3163         }
3164
3165         var = create_var(hist_data, file, field_name, val->size, val->type);
3166         if (IS_ERR(var)) {
3167                 hist_err(tr, HIST_ERR_VAR_CREATE_FIND_FAIL, errpos(field_name));
3168                 kfree(val);
3169                 ret = PTR_ERR(var);
3170                 goto err;
3171         }
3172
3173         field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
3174         if (!field_var) {
3175                 kfree(val);
3176                 kfree(var);
3177                 ret =  -ENOMEM;
3178                 goto err;
3179         }
3180
3181         field_var->var = var;
3182         field_var->val = val;
3183  out:
3184         return field_var;
3185  err:
3186         field_var = ERR_PTR(ret);
3187         goto out;
3188 }
3189
3190 /**
3191  * create_target_field_var - Automatically create a variable for a field
3192  * @target_hist_data: The target hist trigger
3193  * @subsys_name: Optional subsystem name
3194  * @event_name: Optional event name
3195  * @var_name: The name of the field (and the resulting variable)
3196  *
3197  * Hist trigger actions fetch data from variables, not directly from
3198  * events.  However, for convenience, users are allowed to directly
3199  * specify an event field in an action, which will be automatically
3200  * converted into a variable on their behalf.
3201
3202  * This function creates a field variable with the name var_name on
3203  * the hist trigger currently being defined on the target event.  If
3204  * subsys_name and event_name are specified, this function simply
3205  * verifies that they do in fact match the target event subsystem and
3206  * event name.
3207  *
3208  * Return: The variable created for the field.
3209  */
3210 static struct field_var *
3211 create_target_field_var(struct hist_trigger_data *target_hist_data,
3212                         char *subsys_name, char *event_name, char *var_name)
3213 {
3214         struct trace_event_file *file = target_hist_data->event_file;
3215
3216         if (subsys_name) {
3217                 struct trace_event_call *call;
3218
3219                 if (!event_name)
3220                         return NULL;
3221
3222                 call = file->event_call;
3223
3224                 if (strcmp(subsys_name, call->class->system) != 0)
3225                         return NULL;
3226
3227                 if (strcmp(event_name, trace_event_name(call)) != 0)
3228                         return NULL;
3229         }
3230
3231         return create_field_var(target_hist_data, file, var_name);
3232 }
3233
3234 static bool check_track_val_max(u64 track_val, u64 var_val)
3235 {
3236         if (var_val <= track_val)
3237                 return false;
3238
3239         return true;
3240 }
3241
3242 static bool check_track_val_changed(u64 track_val, u64 var_val)
3243 {
3244         if (var_val == track_val)
3245                 return false;
3246
3247         return true;
3248 }
3249
3250 static u64 get_track_val(struct hist_trigger_data *hist_data,
3251                          struct tracing_map_elt *elt,
3252                          struct action_data *data)
3253 {
3254         unsigned int track_var_idx = data->track_data.track_var->var.idx;
3255         u64 track_val;
3256
3257         track_val = tracing_map_read_var(elt, track_var_idx);
3258
3259         return track_val;
3260 }
3261
3262 static void save_track_val(struct hist_trigger_data *hist_data,
3263                            struct tracing_map_elt *elt,
3264                            struct action_data *data, u64 var_val)
3265 {
3266         unsigned int track_var_idx = data->track_data.track_var->var.idx;
3267
3268         tracing_map_set_var(elt, track_var_idx, var_val);
3269 }
3270
3271 static void save_track_data(struct hist_trigger_data *hist_data,
3272                             struct tracing_map_elt *elt,
3273                             struct trace_buffer *buffer, void *rec,
3274                             struct ring_buffer_event *rbe, void *key,
3275                             struct action_data *data, u64 *var_ref_vals)
3276 {
3277         if (data->track_data.save_data)
3278                 data->track_data.save_data(hist_data, elt, buffer, rec, rbe,
3279                                            key, data, var_ref_vals);
3280 }
3281
3282 static bool check_track_val(struct tracing_map_elt *elt,
3283                             struct action_data *data,
3284                             u64 var_val)
3285 {
3286         struct hist_trigger_data *hist_data;
3287         u64 track_val;
3288
3289         hist_data = data->track_data.track_var->hist_data;
3290         track_val = get_track_val(hist_data, elt, data);
3291
3292         return data->track_data.check_val(track_val, var_val);
3293 }
3294
3295 #ifdef CONFIG_TRACER_SNAPSHOT
3296 static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3297 {
3298         /* called with tr->max_lock held */
3299         struct track_data *track_data = tr->cond_snapshot->cond_data;
3300         struct hist_elt_data *elt_data, *track_elt_data;
3301         struct snapshot_context *context = cond_data;
3302         struct action_data *action;
3303         u64 track_val;
3304
3305         if (!track_data)
3306                 return false;
3307
3308         action = track_data->action_data;
3309
3310         track_val = get_track_val(track_data->hist_data, context->elt,
3311                                   track_data->action_data);
3312
3313         if (!action->track_data.check_val(track_data->track_val, track_val))
3314                 return false;
3315
3316         track_data->track_val = track_val;
3317         memcpy(track_data->key, context->key, track_data->key_len);
3318
3319         elt_data = context->elt->private_data;
3320         track_elt_data = track_data->elt.private_data;
3321         if (elt_data->comm)
3322                 strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
3323
3324         track_data->updated = true;
3325
3326         return true;
3327 }
3328
3329 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3330                                      struct tracing_map_elt *elt,
3331                                      struct trace_buffer *buffer, void *rec,
3332                                      struct ring_buffer_event *rbe, void *key,
3333                                      struct action_data *data,
3334                                      u64 *var_ref_vals)
3335 {
3336         struct trace_event_file *file = hist_data->event_file;
3337         struct snapshot_context context;
3338
3339         context.elt = elt;
3340         context.key = key;
3341
3342         tracing_snapshot_cond(file->tr, &context);
3343 }
3344
3345 static void hist_trigger_print_key(struct seq_file *m,
3346                                    struct hist_trigger_data *hist_data,
3347                                    void *key,
3348                                    struct tracing_map_elt *elt);
3349
3350 static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
3351 {
3352         unsigned int i;
3353
3354         if (!hist_data->n_actions)
3355                 return NULL;
3356
3357         for (i = 0; i < hist_data->n_actions; i++) {
3358                 struct action_data *data = hist_data->actions[i];
3359
3360                 if (data->action == ACTION_SNAPSHOT)
3361                         return data;
3362         }
3363
3364         return NULL;
3365 }
3366
3367 static void track_data_snapshot_print(struct seq_file *m,
3368                                       struct hist_trigger_data *hist_data)
3369 {
3370         struct trace_event_file *file = hist_data->event_file;
3371         struct track_data *track_data;
3372         struct action_data *action;
3373
3374         track_data = tracing_cond_snapshot_data(file->tr);
3375         if (!track_data)
3376                 return;
3377
3378         if (!track_data->updated)
3379                 return;
3380
3381         action = snapshot_action(hist_data);
3382         if (!action)
3383                 return;
3384
3385         seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
3386         seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
3387                    action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
3388                    action->track_data.var_str, track_data->track_val);
3389
3390         seq_puts(m, "\ttriggered by event with key: ");
3391         hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
3392         seq_putc(m, '\n');
3393 }
3394 #else
3395 static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3396 {
3397         return false;
3398 }
3399 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3400                                      struct tracing_map_elt *elt,
3401                                      struct trace_buffer *buffer, void *rec,
3402                                      struct ring_buffer_event *rbe, void *key,
3403                                      struct action_data *data,
3404                                      u64 *var_ref_vals) {}
3405 static void track_data_snapshot_print(struct seq_file *m,
3406                                       struct hist_trigger_data *hist_data) {}
3407 #endif /* CONFIG_TRACER_SNAPSHOT */
3408
3409 static void track_data_print(struct seq_file *m,
3410                              struct hist_trigger_data *hist_data,
3411                              struct tracing_map_elt *elt,
3412                              struct action_data *data)
3413 {
3414         u64 track_val = get_track_val(hist_data, elt, data);
3415         unsigned int i, save_var_idx;
3416
3417         if (data->handler == HANDLER_ONMAX)
3418                 seq_printf(m, "\n\tmax: %10llu", track_val);
3419         else if (data->handler == HANDLER_ONCHANGE)
3420                 seq_printf(m, "\n\tchanged: %10llu", track_val);
3421
3422         if (data->action == ACTION_SNAPSHOT)
3423                 return;
3424
3425         for (i = 0; i < hist_data->n_save_vars; i++) {
3426                 struct hist_field *save_val = hist_data->save_vars[i]->val;
3427                 struct hist_field *save_var = hist_data->save_vars[i]->var;
3428                 u64 val;
3429
3430                 save_var_idx = save_var->var.idx;
3431
3432                 val = tracing_map_read_var(elt, save_var_idx);
3433
3434                 if (save_val->flags & HIST_FIELD_FL_STRING) {
3435                         seq_printf(m, "  %s: %-32s", save_var->var.name,
3436                                    (char *)(uintptr_t)(val));
3437                 } else
3438                         seq_printf(m, "  %s: %10llu", save_var->var.name, val);
3439         }
3440 }
3441
3442 static void ontrack_action(struct hist_trigger_data *hist_data,
3443                            struct tracing_map_elt *elt,
3444                            struct trace_buffer *buffer, void *rec,
3445                            struct ring_buffer_event *rbe, void *key,
3446                            struct action_data *data, u64 *var_ref_vals)
3447 {
3448         u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];
3449
3450         if (check_track_val(elt, data, var_val)) {
3451                 save_track_val(hist_data, elt, data, var_val);
3452                 save_track_data(hist_data, elt, buffer, rec, rbe,
3453                                 key, data, var_ref_vals);
3454         }
3455 }
3456
3457 static void action_data_destroy(struct action_data *data)
3458 {
3459         unsigned int i;
3460
3461         lockdep_assert_held(&event_mutex);
3462
3463         kfree(data->action_name);
3464
3465         for (i = 0; i < data->n_params; i++)
3466                 kfree(data->params[i]);
3467
3468         if (data->synth_event)
3469                 data->synth_event->ref--;
3470
3471         kfree(data->synth_event_name);
3472
3473         kfree(data);
3474 }
3475
3476 static void track_data_destroy(struct hist_trigger_data *hist_data,
3477                                struct action_data *data)
3478 {
3479         struct trace_event_file *file = hist_data->event_file;
3480
3481         destroy_hist_field(data->track_data.track_var, 0);
3482
3483         if (data->action == ACTION_SNAPSHOT) {
3484                 struct track_data *track_data;
3485
3486                 track_data = tracing_cond_snapshot_data(file->tr);
3487                 if (track_data && track_data->hist_data == hist_data) {
3488                         tracing_snapshot_cond_disable(file->tr);
3489                         track_data_free(track_data);
3490                 }
3491         }
3492
3493         kfree(data->track_data.var_str);
3494
3495         action_data_destroy(data);
3496 }
3497
3498 static int action_create(struct hist_trigger_data *hist_data,
3499                          struct action_data *data);
3500
3501 static int track_data_create(struct hist_trigger_data *hist_data,
3502                              struct action_data *data)
3503 {
3504         struct hist_field *var_field, *ref_field, *track_var = NULL;
3505         struct trace_event_file *file = hist_data->event_file;
3506         struct trace_array *tr = file->tr;
3507         char *track_data_var_str;
3508         int ret = 0;
3509
3510         track_data_var_str = data->track_data.var_str;
3511         if (track_data_var_str[0] != '$') {
3512                 hist_err(tr, HIST_ERR_ONX_NOT_VAR, errpos(track_data_var_str));
3513                 return -EINVAL;
3514         }
3515         track_data_var_str++;
3516
3517         var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
3518         if (!var_field) {
3519                 hist_err(tr, HIST_ERR_ONX_VAR_NOT_FOUND, errpos(track_data_var_str));
3520                 return -EINVAL;
3521         }
3522
3523         ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
3524         if (!ref_field)
3525                 return -ENOMEM;
3526
3527         data->track_data.var_ref = ref_field;
3528
3529         if (data->handler == HANDLER_ONMAX)
3530                 track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
3531         if (IS_ERR(track_var)) {
3532                 hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3533                 ret = PTR_ERR(track_var);
3534                 goto out;
3535         }
3536
3537         if (data->handler == HANDLER_ONCHANGE)
3538                 track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
3539         if (IS_ERR(track_var)) {
3540                 hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3541                 ret = PTR_ERR(track_var);
3542                 goto out;
3543         }
3544         data->track_data.track_var = track_var;
3545
3546         ret = action_create(hist_data, data);
3547  out:
3548         return ret;
3549 }
3550
3551 static int parse_action_params(struct trace_array *tr, char *params,
3552                                struct action_data *data)
3553 {
3554         char *param, *saved_param;
3555         bool first_param = true;
3556         int ret = 0;
3557
3558         while (params) {
3559                 if (data->n_params >= SYNTH_FIELDS_MAX) {
3560                         hist_err(tr, HIST_ERR_TOO_MANY_PARAMS, 0);
3561                         goto out;
3562                 }
3563
3564                 param = strsep(&params, ",");
3565                 if (!param) {
3566                         hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, 0);
3567                         ret = -EINVAL;
3568                         goto out;
3569                 }
3570
3571                 param = strstrip(param);
3572                 if (strlen(param) < 2) {
3573                         hist_err(tr, HIST_ERR_INVALID_PARAM, errpos(param));
3574                         ret = -EINVAL;
3575                         goto out;
3576                 }
3577
3578                 saved_param = kstrdup(param, GFP_KERNEL);
3579                 if (!saved_param) {
3580                         ret = -ENOMEM;
3581                         goto out;
3582                 }
3583
3584                 if (first_param && data->use_trace_keyword) {
3585                         data->synth_event_name = saved_param;
3586                         first_param = false;
3587                         continue;
3588                 }
3589                 first_param = false;
3590
3591                 data->params[data->n_params++] = saved_param;
3592         }
3593  out:
3594         return ret;
3595 }
3596
3597 static int action_parse(struct trace_array *tr, char *str, struct action_data *data,
3598                         enum handler_id handler)
3599 {
3600         char *action_name;
3601         int ret = 0;
3602
3603         strsep(&str, ".");
3604         if (!str) {
3605                 hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3606                 ret = -EINVAL;
3607                 goto out;
3608         }
3609
3610         action_name = strsep(&str, "(");
3611         if (!action_name || !str) {
3612                 hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3613                 ret = -EINVAL;
3614                 goto out;
3615         }
3616
3617         if (str_has_prefix(action_name, "save")) {
3618                 char *params = strsep(&str, ")");
3619
3620                 if (!params) {
3621                         hist_err(tr, HIST_ERR_NO_SAVE_PARAMS, 0);
3622                         ret = -EINVAL;
3623                         goto out;
3624                 }
3625
3626                 ret = parse_action_params(tr, params, data);
3627                 if (ret)
3628                         goto out;
3629
3630                 if (handler == HANDLER_ONMAX)
3631                         data->track_data.check_val = check_track_val_max;
3632                 else if (handler == HANDLER_ONCHANGE)
3633                         data->track_data.check_val = check_track_val_changed;
3634                 else {
3635                         hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3636                         ret = -EINVAL;
3637                         goto out;
3638                 }
3639
3640                 data->track_data.save_data = save_track_data_vars;
3641                 data->fn = ontrack_action;
3642                 data->action = ACTION_SAVE;
3643         } else if (str_has_prefix(action_name, "snapshot")) {
3644                 char *params = strsep(&str, ")");
3645
3646                 if (!str) {
3647                         hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(params));
3648                         ret = -EINVAL;
3649                         goto out;
3650                 }
3651
3652                 if (handler == HANDLER_ONMAX)
3653                         data->track_data.check_val = check_track_val_max;
3654                 else if (handler == HANDLER_ONCHANGE)
3655                         data->track_data.check_val = check_track_val_changed;
3656                 else {
3657                         hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3658                         ret = -EINVAL;
3659                         goto out;
3660                 }
3661
3662                 data->track_data.save_data = save_track_data_snapshot;
3663                 data->fn = ontrack_action;
3664                 data->action = ACTION_SNAPSHOT;
3665         } else {
3666                 char *params = strsep(&str, ")");
3667
3668                 if (str_has_prefix(action_name, "trace"))
3669                         data->use_trace_keyword = true;
3670
3671                 if (params) {
3672                         ret = parse_action_params(tr, params, data);
3673                         if (ret)
3674                                 goto out;
3675                 }
3676
3677                 if (handler == HANDLER_ONMAX)
3678                         data->track_data.check_val = check_track_val_max;
3679                 else if (handler == HANDLER_ONCHANGE)
3680                         data->track_data.check_val = check_track_val_changed;
3681
3682                 if (handler != HANDLER_ONMATCH) {
3683                         data->track_data.save_data = action_trace;
3684                         data->fn = ontrack_action;
3685                 } else
3686                         data->fn = action_trace;
3687
3688                 data->action = ACTION_TRACE;
3689         }
3690
3691         data->action_name = kstrdup(action_name, GFP_KERNEL);
3692         if (!data->action_name) {
3693                 ret = -ENOMEM;
3694                 goto out;
3695         }
3696
3697         data->handler = handler;
3698  out:
3699         return ret;
3700 }
3701
3702 static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
3703                                             char *str, enum handler_id handler)
3704 {
3705         struct action_data *data;
3706         int ret = -EINVAL;
3707         char *var_str;
3708
3709         data = kzalloc(sizeof(*data), GFP_KERNEL);
3710         if (!data)
3711                 return ERR_PTR(-ENOMEM);
3712
3713         var_str = strsep(&str, ")");
3714         if (!var_str || !str) {
3715                 ret = -EINVAL;
3716                 goto free;
3717         }
3718
3719         data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
3720         if (!data->track_data.var_str) {
3721                 ret = -ENOMEM;
3722                 goto free;
3723         }
3724
3725         ret = action_parse(hist_data->event_file->tr, str, data, handler);
3726         if (ret)
3727                 goto free;
3728  out:
3729         return data;
3730  free:
3731         track_data_destroy(hist_data, data);
3732         data = ERR_PTR(ret);
3733         goto out;
3734 }
3735
3736 static void onmatch_destroy(struct action_data *data)
3737 {
3738         kfree(data->match_data.event);
3739         kfree(data->match_data.event_system);
3740
3741         action_data_destroy(data);
3742 }
3743
3744 static void destroy_field_var(struct field_var *field_var)
3745 {
3746         if (!field_var)
3747                 return;
3748
3749         destroy_hist_field(field_var->var, 0);
3750         destroy_hist_field(field_var->val, 0);
3751
3752         kfree(field_var);
3753 }
3754
3755 static void destroy_field_vars(struct hist_trigger_data *hist_data)
3756 {
3757         unsigned int i;
3758
3759         for (i = 0; i < hist_data->n_field_vars; i++)
3760                 destroy_field_var(hist_data->field_vars[i]);
3761
3762         for (i = 0; i < hist_data->n_save_vars; i++)
3763                 destroy_field_var(hist_data->save_vars[i]);
3764 }
3765
3766 static void save_field_var(struct hist_trigger_data *hist_data,
3767                            struct field_var *field_var)
3768 {
3769         hist_data->field_vars[hist_data->n_field_vars++] = field_var;
3770
3771         if (field_var->val->flags & HIST_FIELD_FL_STRING)
3772                 hist_data->n_field_var_str++;
3773 }
3774
3775
3776 static int check_synth_field(struct synth_event *event,
3777                              struct hist_field *hist_field,
3778                              unsigned int field_pos)
3779 {
3780         struct synth_field *field;
3781
3782         if (field_pos >= event->n_fields)
3783                 return -EINVAL;
3784
3785         field = event->fields[field_pos];
3786
3787         /*
3788          * A dynamic string synth field can accept static or
3789          * dynamic. A static string synth field can only accept a
3790          * same-sized static string, which is checked for later.
3791          */
3792         if (strstr(hist_field->type, "char[") && field->is_string
3793             && field->is_dynamic)
3794                 return 0;
3795
3796         if (strcmp(field->type, hist_field->type) != 0) {
3797                 if (field->size != hist_field->size ||
3798                     (!field->is_string && field->is_signed != hist_field->is_signed))
3799                         return -EINVAL;
3800         }
3801
3802         return 0;
3803 }
3804
3805 static struct hist_field *
3806 trace_action_find_var(struct hist_trigger_data *hist_data,
3807                       struct action_data *data,
3808                       char *system, char *event, char *var)
3809 {
3810         struct trace_array *tr = hist_data->event_file->tr;
3811         struct hist_field *hist_field;
3812
3813         var++; /* skip '$' */
3814
3815         hist_field = find_target_event_var(hist_data, system, event, var);
3816         if (!hist_field) {
3817                 if (!system && data->handler == HANDLER_ONMATCH) {
3818                         system = data->match_data.event_system;
3819                         event = data->match_data.event;
3820                 }
3821
3822                 hist_field = find_event_var(hist_data, system, event, var);
3823         }
3824
3825         if (!hist_field)
3826                 hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, errpos(var));
3827
3828         return hist_field;
3829 }
3830
3831 static struct hist_field *
3832 trace_action_create_field_var(struct hist_trigger_data *hist_data,
3833                               struct action_data *data, char *system,
3834                               char *event, char *var)
3835 {
3836         struct hist_field *hist_field = NULL;
3837         struct field_var *field_var;
3838
3839         /*
3840          * First try to create a field var on the target event (the
3841          * currently being defined).  This will create a variable for
3842          * unqualified fields on the target event, or if qualified,
3843          * target fields that have qualified names matching the target.
3844          */
3845         field_var = create_target_field_var(hist_data, system, event, var);
3846
3847         if (field_var && !IS_ERR(field_var)) {
3848                 save_field_var(hist_data, field_var);
3849                 hist_field = field_var->var;
3850         } else {
3851                 field_var = NULL;
3852                 /*
3853                  * If no explicit system.event is specified, default to
3854                  * looking for fields on the onmatch(system.event.xxx)
3855                  * event.
3856                  */
3857                 if (!system && data->handler == HANDLER_ONMATCH) {
3858                         system = data->match_data.event_system;
3859                         event = data->match_data.event;
3860                 }
3861
3862                 if (!event)
3863                         goto free;
3864                 /*
3865                  * At this point, we're looking at a field on another
3866                  * event.  Because we can't modify a hist trigger on
3867                  * another event to add a variable for a field, we need
3868                  * to create a new trigger on that event and create the
3869                  * variable at the same time.
3870                  */
3871                 hist_field = create_field_var_hist(hist_data, system, event, var);
3872                 if (IS_ERR(hist_field))
3873                         goto free;
3874         }
3875  out:
3876         return hist_field;
3877  free:
3878         destroy_field_var(field_var);
3879         hist_field = NULL;
3880         goto out;
3881 }
3882
3883 static int trace_action_create(struct hist_trigger_data *hist_data,
3884                                struct action_data *data)
3885 {
3886         struct trace_array *tr = hist_data->event_file->tr;
3887         char *event_name, *param, *system = NULL;
3888         struct hist_field *hist_field, *var_ref;
3889         unsigned int i;
3890         unsigned int field_pos = 0;
3891         struct synth_event *event;
3892         char *synth_event_name;
3893         int var_ref_idx, ret = 0;
3894
3895         lockdep_assert_held(&event_mutex);
3896
3897         if (data->use_trace_keyword)
3898                 synth_event_name = data->synth_event_name;
3899         else
3900                 synth_event_name = data->action_name;
3901
3902         event = find_synth_event(synth_event_name);
3903         if (!event) {
3904                 hist_err(tr, HIST_ERR_SYNTH_EVENT_NOT_FOUND, errpos(synth_event_name));
3905                 return -EINVAL;
3906         }
3907
3908         event->ref++;
3909
3910         for (i = 0; i < data->n_params; i++) {
3911                 char *p;
3912
3913                 p = param = kstrdup(data->params[i], GFP_KERNEL);
3914                 if (!param) {
3915                         ret = -ENOMEM;
3916                         goto err;
3917                 }
3918
3919                 system = strsep(&param, ".");
3920                 if (!param) {
3921                         param = (char *)system;
3922                         system = event_name = NULL;
3923                 } else {
3924                         event_name = strsep(&param, ".");
3925                         if (!param) {
3926                                 kfree(p);
3927                                 ret = -EINVAL;
3928                                 goto err;
3929                         }
3930                 }
3931
3932                 if (param[0] == '$')
3933                         hist_field = trace_action_find_var(hist_data, data,
3934                                                            system, event_name,
3935                                                            param);
3936                 else
3937                         hist_field = trace_action_create_field_var(hist_data,
3938                                                                    data,
3939                                                                    system,
3940                                                                    event_name,
3941                                                                    param);
3942
3943                 if (!hist_field) {
3944                         kfree(p);
3945                         ret = -EINVAL;
3946                         goto err;
3947                 }
3948
3949                 if (check_synth_field(event, hist_field, field_pos) == 0) {
3950                         var_ref = create_var_ref(hist_data, hist_field,
3951                                                  system, event_name);
3952                         if (!var_ref) {
3953                                 kfree(p);
3954                                 ret = -ENOMEM;
3955                                 goto err;
3956                         }
3957
3958                         var_ref_idx = find_var_ref_idx(hist_data, var_ref);
3959                         if (WARN_ON(var_ref_idx < 0)) {
3960                                 kfree(p);
3961                                 ret = var_ref_idx;
3962                                 goto err;
3963                         }
3964
3965                         data->var_ref_idx[i] = var_ref_idx;
3966
3967                         field_pos++;
3968                         kfree(p);
3969                         continue;
3970                 }
3971
3972                 hist_err(tr, HIST_ERR_SYNTH_TYPE_MISMATCH, errpos(param));
3973                 kfree(p);
3974                 ret = -EINVAL;
3975                 goto err;
3976         }
3977
3978         if (field_pos != event->n_fields) {
3979                 hist_err(tr, HIST_ERR_SYNTH_COUNT_MISMATCH, errpos(event->name));
3980                 ret = -EINVAL;
3981                 goto err;
3982         }
3983
3984         data->synth_event = event;
3985  out:
3986         return ret;
3987  err:
3988         event->ref--;
3989
3990         goto out;
3991 }
3992
3993 static int action_create(struct hist_trigger_data *hist_data,
3994                          struct action_data *data)
3995 {
3996         struct trace_event_file *file = hist_data->event_file;
3997         struct trace_array *tr = file->tr;
3998         struct track_data *track_data;
3999         struct field_var *field_var;
4000         unsigned int i;
4001         char *param;
4002         int ret = 0;
4003
4004         if (data->action == ACTION_TRACE)
4005                 return trace_action_create(hist_data, data);
4006
4007         if (data->action == ACTION_SNAPSHOT) {
4008                 track_data = track_data_alloc(hist_data->key_size, data, hist_data);
4009                 if (IS_ERR(track_data)) {
4010                         ret = PTR_ERR(track_data);
4011                         goto out;
4012                 }
4013
4014                 ret = tracing_snapshot_cond_enable(file->tr, track_data,
4015                                                    cond_snapshot_update);
4016                 if (ret)
4017                         track_data_free(track_data);
4018
4019                 goto out;
4020         }
4021
4022         if (data->action == ACTION_SAVE) {
4023                 if (hist_data->n_save_vars) {
4024                         ret = -EEXIST;
4025                         hist_err(tr, HIST_ERR_TOO_MANY_SAVE_ACTIONS, 0);
4026                         goto out;
4027                 }
4028
4029                 for (i = 0; i < data->n_params; i++) {
4030                         param = kstrdup(data->params[i], GFP_KERNEL);
4031                         if (!param) {
4032                                 ret = -ENOMEM;
4033                                 goto out;
4034                         }
4035
4036                         field_var = create_target_field_var(hist_data, NULL, NULL, param);
4037                         if (IS_ERR(field_var)) {
4038                                 hist_err(tr, HIST_ERR_FIELD_VAR_CREATE_FAIL,
4039                                          errpos(param));
4040                                 ret = PTR_ERR(field_var);
4041                                 kfree(param);
4042                                 goto out;
4043                         }
4044
4045                         hist_data->save_vars[hist_data->n_save_vars++] = field_var;
4046                         if (field_var->val->flags & HIST_FIELD_FL_STRING)
4047                                 hist_data->n_save_var_str++;
4048                         kfree(param);
4049                 }
4050         }
4051  out:
4052         return ret;
4053 }
4054
4055 static int onmatch_create(struct hist_trigger_data *hist_data,
4056                           struct action_data *data)
4057 {
4058         return action_create(hist_data, data);
4059 }
4060
4061 static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
4062 {
4063         char *match_event, *match_event_system;
4064         struct action_data *data;
4065         int ret = -EINVAL;
4066
4067         data = kzalloc(sizeof(*data), GFP_KERNEL);
4068         if (!data)
4069                 return ERR_PTR(-ENOMEM);
4070
4071         match_event = strsep(&str, ")");
4072         if (!match_event || !str) {
4073                 hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(match_event));
4074                 goto free;
4075         }
4076
4077         match_event_system = strsep(&match_event, ".");
4078         if (!match_event) {
4079                 hist_err(tr, HIST_ERR_SUBSYS_NOT_FOUND, errpos(match_event_system));
4080                 goto free;
4081         }
4082
4083         if (IS_ERR(event_file(tr, match_event_system, match_event))) {
4084                 hist_err(tr, HIST_ERR_INVALID_SUBSYS_EVENT, errpos(match_event));
4085                 goto free;
4086         }
4087
4088         data->match_data.event = kstrdup(match_event, GFP_KERNEL);
4089         if (!data->match_data.event) {
4090                 ret = -ENOMEM;
4091                 goto free;
4092         }
4093
4094         data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
4095         if (!data->match_data.event_system) {
4096                 ret = -ENOMEM;
4097                 goto free;
4098         }
4099
4100         ret = action_parse(tr, str, data, HANDLER_ONMATCH);
4101         if (ret)
4102                 goto free;
4103  out:
4104         return data;
4105  free:
4106         onmatch_destroy(data);
4107         data = ERR_PTR(ret);
4108         goto out;
4109 }
4110
4111 static int create_hitcount_val(struct hist_trigger_data *hist_data)
4112 {
4113         hist_data->fields[HITCOUNT_IDX] =
4114                 create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
4115         if (!hist_data->fields[HITCOUNT_IDX])
4116                 return -ENOMEM;
4117
4118         hist_data->n_vals++;
4119         hist_data->n_fields++;
4120
4121         if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
4122                 return -EINVAL;
4123
4124         return 0;
4125 }
4126
4127 static int __create_val_field(struct hist_trigger_data *hist_data,
4128                               unsigned int val_idx,
4129                               struct trace_event_file *file,
4130                               char *var_name, char *field_str,
4131                               unsigned long flags)
4132 {
4133         struct hist_field *hist_field;
4134         int ret = 0, n_subexprs = 0;
4135
4136         hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs);
4137         if (IS_ERR(hist_field)) {
4138                 ret = PTR_ERR(hist_field);
4139                 goto out;
4140         }
4141
4142         hist_data->fields[val_idx] = hist_field;
4143
4144         ++hist_data->n_vals;
4145         ++hist_data->n_fields;
4146
4147         if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4148                 ret = -EINVAL;
4149  out:
4150         return ret;
4151 }
4152
4153 static int create_val_field(struct hist_trigger_data *hist_data,
4154                             unsigned int val_idx,
4155                             struct trace_event_file *file,
4156                             char *field_str)
4157 {
4158         if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
4159                 return -EINVAL;
4160
4161         return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
4162 }
4163
4164 static const char *no_comm = "(no comm)";
4165
4166 static u64 hist_field_execname(struct hist_field *hist_field,
4167                                struct tracing_map_elt *elt,
4168                                struct trace_buffer *buffer,
4169                                struct ring_buffer_event *rbe,
4170                                void *event)
4171 {
4172         struct hist_elt_data *elt_data;
4173
4174         if (WARN_ON_ONCE(!elt))
4175                 return (u64)(unsigned long)no_comm;
4176
4177         elt_data = elt->private_data;
4178
4179         if (WARN_ON_ONCE(!elt_data->comm))
4180                 return (u64)(unsigned long)no_comm;
4181
4182         return (u64)(unsigned long)(elt_data->comm);
4183 }
4184
4185 /* Convert a var that points to common_pid.execname to a string */
4186 static void update_var_execname(struct hist_field *hist_field)
4187 {
4188         hist_field->flags = HIST_FIELD_FL_STRING | HIST_FIELD_FL_VAR |
4189                 HIST_FIELD_FL_EXECNAME;
4190         hist_field->size = MAX_FILTER_STR_VAL;
4191         hist_field->is_signed = 0;
4192
4193         kfree_const(hist_field->type);
4194         hist_field->type = "char[]";
4195
4196         hist_field->fn = hist_field_execname;
4197 }
4198
4199 static int create_var_field(struct hist_trigger_data *hist_data,
4200                             unsigned int val_idx,
4201                             struct trace_event_file *file,
4202                             char *var_name, char *expr_str)
4203 {
4204         struct trace_array *tr = hist_data->event_file->tr;
4205         unsigned long flags = 0;
4206         int ret;
4207
4208         if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4209                 return -EINVAL;
4210
4211         if (find_var(hist_data, file, var_name) && !hist_data->remove) {
4212                 hist_err(tr, HIST_ERR_DUPLICATE_VAR, errpos(var_name));
4213                 return -EINVAL;
4214         }
4215
4216         flags |= HIST_FIELD_FL_VAR;
4217         hist_data->n_vars++;
4218         if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
4219                 return -EINVAL;
4220
4221         ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
4222
4223         if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
4224                 update_var_execname(hist_data->fields[val_idx]);
4225
4226         if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
4227                 hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
4228
4229         return ret;
4230 }
4231
4232 static int create_val_fields(struct hist_trigger_data *hist_data,
4233                              struct trace_event_file *file)
4234 {
4235         char *fields_str, *field_str;
4236         unsigned int i, j = 1;
4237         int ret;
4238
4239         ret = create_hitcount_val(hist_data);
4240         if (ret)
4241                 goto out;
4242
4243         fields_str = hist_data->attrs->vals_str;
4244         if (!fields_str)
4245                 goto out;
4246
4247         for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
4248                      j < TRACING_MAP_VALS_MAX; i++) {
4249                 field_str = strsep(&fields_str, ",");
4250                 if (!field_str)
4251                         break;
4252
4253                 if (strcmp(field_str, "hitcount") == 0)
4254                         continue;
4255
4256                 ret = create_val_field(hist_data, j++, file, field_str);
4257                 if (ret)
4258                         goto out;
4259         }
4260
4261         if (fields_str && (strcmp(fields_str, "hitcount") != 0))
4262                 ret = -EINVAL;
4263  out:
4264         return ret;
4265 }
4266
4267 static int create_key_field(struct hist_trigger_data *hist_data,
4268                             unsigned int key_idx,
4269                             unsigned int key_offset,
4270                             struct trace_event_file *file,
4271                             char *field_str)
4272 {
4273         struct trace_array *tr = hist_data->event_file->tr;
4274         struct hist_field *hist_field = NULL;
4275         unsigned long flags = 0;
4276         unsigned int key_size;
4277         int ret = 0, n_subexprs = 0;
4278
4279         if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
4280                 return -EINVAL;
4281
4282         flags |= HIST_FIELD_FL_KEY;
4283
4284         if (strcmp(field_str, "stacktrace") == 0) {
4285                 flags |= HIST_FIELD_FL_STACKTRACE;
4286                 key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
4287                 hist_field = create_hist_field(hist_data, NULL, flags, NULL);
4288         } else {
4289                 hist_field = parse_expr(hist_data, file, field_str, flags,
4290                                         NULL, &n_subexprs);
4291                 if (IS_ERR(hist_field)) {
4292                         ret = PTR_ERR(hist_field);
4293                         goto out;
4294                 }
4295
4296                 if (field_has_hist_vars(hist_field, 0)) {
4297                         hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
4298                         destroy_hist_field(hist_field, 0);
4299                         ret = -EINVAL;
4300                         goto out;
4301                 }
4302
4303                 key_size = hist_field->size;
4304         }
4305
4306         hist_data->fields[key_idx] = hist_field;
4307
4308         key_size = ALIGN(key_size, sizeof(u64));
4309         hist_data->fields[key_idx]->size = key_size;
4310         hist_data->fields[key_idx]->offset = key_offset;
4311
4312         hist_data->key_size += key_size;
4313
4314         if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
4315                 ret = -EINVAL;
4316                 goto out;
4317         }
4318
4319         hist_data->n_keys++;
4320         hist_data->n_fields++;
4321
4322         if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
4323                 return -EINVAL;
4324
4325         ret = key_size;
4326  out:
4327         return ret;
4328 }
4329
4330 static int create_key_fields(struct hist_trigger_data *hist_data,
4331                              struct trace_event_file *file)
4332 {
4333         unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
4334         char *fields_str, *field_str;
4335         int ret = -EINVAL;
4336
4337         fields_str = hist_data->attrs->keys_str;
4338         if (!fields_str)
4339                 goto out;
4340
4341         for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
4342                 field_str = strsep(&fields_str, ",");
4343                 if (!field_str)
4344                         break;
4345                 ret = create_key_field(hist_data, i, key_offset,
4346                                        file, field_str);
4347                 if (ret < 0)
4348                         goto out;
4349                 key_offset += ret;
4350         }
4351         if (fields_str) {
4352                 ret = -EINVAL;
4353                 goto out;
4354         }
4355         ret = 0;
4356  out:
4357         return ret;
4358 }
4359
4360 static int create_var_fields(struct hist_trigger_data *hist_data,
4361                              struct trace_event_file *file)
4362 {
4363         unsigned int i, j = hist_data->n_vals;
4364         int ret = 0;
4365
4366         unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
4367
4368         for (i = 0; i < n_vars; i++) {
4369                 char *var_name = hist_data->attrs->var_defs.name[i];
4370                 char *expr = hist_data->attrs->var_defs.expr[i];
4371
4372                 ret = create_var_field(hist_data, j++, file, var_name, expr);
4373                 if (ret)
4374                         goto out;
4375         }
4376  out:
4377         return ret;
4378 }
4379
4380 static void free_var_defs(struct hist_trigger_data *hist_data)
4381 {
4382         unsigned int i;
4383
4384         for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
4385                 kfree(hist_data->attrs->var_defs.name[i]);
4386                 kfree(hist_data->attrs->var_defs.expr[i]);
4387         }
4388
4389         hist_data->attrs->var_defs.n_vars = 0;
4390 }
4391
4392 static int parse_var_defs(struct hist_trigger_data *hist_data)
4393 {
4394         struct trace_array *tr = hist_data->event_file->tr;
4395         char *s, *str, *var_name, *field_str;
4396         unsigned int i, j, n_vars = 0;
4397         int ret = 0;
4398
4399         for (i = 0; i < hist_data->attrs->n_assignments; i++) {
4400                 str = hist_data->attrs->assignment_str[i];
4401                 for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
4402                         field_str = strsep(&str, ",");
4403                         if (!field_str)
4404                                 break;
4405
4406                         var_name = strsep(&field_str, "=");
4407                         if (!var_name || !field_str) {
4408                                 hist_err(tr, HIST_ERR_MALFORMED_ASSIGNMENT,
4409                                          errpos(var_name));
4410                                 ret = -EINVAL;
4411                                 goto free;
4412                         }
4413
4414                         if (n_vars == TRACING_MAP_VARS_MAX) {
4415                                 hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(var_name));
4416                                 ret = -EINVAL;
4417                                 goto free;
4418                         }
4419
4420                         s = kstrdup(var_name, GFP_KERNEL);
4421                         if (!s) {
4422                                 ret = -ENOMEM;
4423                                 goto free;
4424                         }
4425                         hist_data->attrs->var_defs.name[n_vars] = s;
4426
4427                         s = kstrdup(field_str, GFP_KERNEL);
4428                         if (!s) {
4429                                 ret = -ENOMEM;
4430                                 goto free;
4431                         }
4432                         hist_data->attrs->var_defs.expr[n_vars++] = s;
4433
4434                         hist_data->attrs->var_defs.n_vars = n_vars;
4435                 }
4436         }
4437
4438         return ret;
4439  free:
4440         free_var_defs(hist_data);
4441
4442         return ret;
4443 }
4444
4445 static int create_hist_fields(struct hist_trigger_data *hist_data,
4446                               struct trace_event_file *file)
4447 {
4448         int ret;
4449
4450         ret = parse_var_defs(hist_data);
4451         if (ret)
4452                 goto out;
4453
4454         ret = create_val_fields(hist_data, file);
4455         if (ret)
4456                 goto out;
4457
4458         ret = create_var_fields(hist_data, file);
4459         if (ret)
4460                 goto out;
4461
4462         ret = create_key_fields(hist_data, file);
4463         if (ret)
4464                 goto out;
4465  out:
4466         free_var_defs(hist_data);
4467
4468         return ret;
4469 }
4470
4471 static int is_descending(struct trace_array *tr, const char *str)
4472 {
4473         if (!str)
4474                 return 0;
4475
4476         if (strcmp(str, "descending") == 0)
4477                 return 1;
4478
4479         if (strcmp(str, "ascending") == 0)
4480                 return 0;
4481
4482         hist_err(tr, HIST_ERR_INVALID_SORT_MODIFIER, errpos((char *)str));
4483
4484         return -EINVAL;
4485 }
4486
4487 static int create_sort_keys(struct hist_trigger_data *hist_data)
4488 {
4489         struct trace_array *tr = hist_data->event_file->tr;
4490         char *fields_str = hist_data->attrs->sort_key_str;
4491         struct tracing_map_sort_key *sort_key;
4492         int descending, ret = 0;
4493         unsigned int i, j, k;
4494
4495         hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
4496
4497         if (!fields_str)
4498                 goto out;
4499
4500         for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
4501                 struct hist_field *hist_field;
4502                 char *field_str, *field_name;
4503                 const char *test_name;
4504
4505                 sort_key = &hist_data->sort_keys[i];
4506
4507                 field_str = strsep(&fields_str, ",");
4508                 if (!field_str)
4509                         break;
4510
4511                 if (!*field_str) {
4512                         ret = -EINVAL;
4513                         hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4514                         break;
4515                 }
4516
4517                 if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
4518                         hist_err(tr, HIST_ERR_TOO_MANY_SORT_FIELDS, errpos("sort="));
4519                         ret = -EINVAL;
4520                         break;
4521                 }
4522
4523                 field_name = strsep(&field_str, ".");
4524                 if (!field_name || !*field_name) {
4525                         ret = -EINVAL;
4526                         hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4527                         break;
4528                 }
4529
4530                 if (strcmp(field_name, "hitcount") == 0) {
4531                         descending = is_descending(tr, field_str);
4532                         if (descending < 0) {
4533                                 ret = descending;
4534                                 break;
4535                         }
4536                         sort_key->descending = descending;
4537                         continue;
4538                 }
4539
4540                 for (j = 1, k = 1; j < hist_data->n_fields; j++) {
4541                         unsigned int idx;
4542
4543                         hist_field = hist_data->fields[j];
4544                         if (hist_field->flags & HIST_FIELD_FL_VAR)
4545                                 continue;
4546
4547                         idx = k++;
4548
4549                         test_name = hist_field_name(hist_field, 0);
4550
4551                         if (strcmp(field_name, test_name) == 0) {
4552                                 sort_key->field_idx = idx;
4553                                 descending = is_descending(tr, field_str);
4554                                 if (descending < 0) {
4555                                         ret = descending;
4556                                         goto out;
4557                                 }
4558                                 sort_key->descending = descending;
4559                                 break;
4560                         }
4561                 }
4562                 if (j == hist_data->n_fields) {
4563                         ret = -EINVAL;
4564                         hist_err(tr, HIST_ERR_INVALID_SORT_FIELD, errpos(field_name));
4565                         break;
4566                 }
4567         }
4568
4569         hist_data->n_sort_keys = i;
4570  out:
4571         return ret;
4572 }
4573
4574 static void destroy_actions(struct hist_trigger_data *hist_data)
4575 {
4576         unsigned int i;
4577
4578         for (i = 0; i < hist_data->n_actions; i++) {
4579                 struct action_data *data = hist_data->actions[i];
4580
4581                 if (data->handler == HANDLER_ONMATCH)
4582                         onmatch_destroy(data);
4583                 else if (data->handler == HANDLER_ONMAX ||
4584                          data->handler == HANDLER_ONCHANGE)
4585                         track_data_destroy(hist_data, data);
4586                 else
4587                         kfree(data);
4588         }
4589 }
4590
4591 static int parse_actions(struct hist_trigger_data *hist_data)
4592 {
4593         struct trace_array *tr = hist_data->event_file->tr;
4594         struct action_data *data;
4595         unsigned int i;
4596         int ret = 0;
4597         char *str;
4598         int len;
4599
4600         for (i = 0; i < hist_data->attrs->n_actions; i++) {
4601                 str = hist_data->attrs->action_str[i];
4602
4603                 if ((len = str_has_prefix(str, "onmatch("))) {
4604                         char *action_str = str + len;
4605
4606                         data = onmatch_parse(tr, action_str);
4607                         if (IS_ERR(data)) {
4608                                 ret = PTR_ERR(data);
4609                                 break;
4610                         }
4611                 } else if ((len = str_has_prefix(str, "onmax("))) {
4612                         char *action_str = str + len;
4613
4614                         data = track_data_parse(hist_data, action_str,
4615                                                 HANDLER_ONMAX);
4616                         if (IS_ERR(data)) {
4617                                 ret = PTR_ERR(data);
4618                                 break;
4619                         }
4620                 } else if ((len = str_has_prefix(str, "onchange("))) {
4621                         char *action_str = str + len;
4622
4623                         data = track_data_parse(hist_data, action_str,
4624                                                 HANDLER_ONCHANGE);
4625                         if (IS_ERR(data)) {
4626                                 ret = PTR_ERR(data);
4627                                 break;
4628                         }
4629                 } else {
4630                         ret = -EINVAL;
4631                         break;
4632                 }
4633
4634                 hist_data->actions[hist_data->n_actions++] = data;
4635         }
4636
4637         return ret;
4638 }
4639
4640 static int create_actions(struct hist_trigger_data *hist_data)
4641 {
4642         struct action_data *data;
4643         unsigned int i;
4644         int ret = 0;
4645
4646         for (i = 0; i < hist_data->attrs->n_actions; i++) {
4647                 data = hist_data->actions[i];
4648
4649                 if (data->handler == HANDLER_ONMATCH) {
4650                         ret = onmatch_create(hist_data, data);
4651                         if (ret)
4652                                 break;
4653                 } else if (data->handler == HANDLER_ONMAX ||
4654                            data->handler == HANDLER_ONCHANGE) {
4655                         ret = track_data_create(hist_data, data);
4656                         if (ret)
4657                                 break;
4658                 } else {
4659                         ret = -EINVAL;
4660                         break;
4661                 }
4662         }
4663
4664         return ret;
4665 }
4666
4667 static void print_actions(struct seq_file *m,
4668                           struct hist_trigger_data *hist_data,
4669                           struct tracing_map_elt *elt)
4670 {
4671         unsigned int i;
4672
4673         for (i = 0; i < hist_data->n_actions; i++) {
4674                 struct action_data *data = hist_data->actions[i];
4675
4676                 if (data->action == ACTION_SNAPSHOT)
4677                         continue;
4678
4679                 if (data->handler == HANDLER_ONMAX ||
4680                     data->handler == HANDLER_ONCHANGE)
4681                         track_data_print(m, hist_data, elt, data);
4682         }
4683 }
4684
4685 static void print_action_spec(struct seq_file *m,
4686                               struct hist_trigger_data *hist_data,
4687                               struct action_data *data)
4688 {
4689         unsigned int i;
4690
4691         if (data->action == ACTION_SAVE) {
4692                 for (i = 0; i < hist_data->n_save_vars; i++) {
4693                         seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
4694                         if (i < hist_data->n_save_vars - 1)
4695                                 seq_puts(m, ",");
4696                 }
4697         } else if (data->action == ACTION_TRACE) {
4698                 if (data->use_trace_keyword)
4699                         seq_printf(m, "%s", data->synth_event_name);
4700                 for (i = 0; i < data->n_params; i++) {
4701                         if (i || data->use_trace_keyword)
4702                                 seq_puts(m, ",");
4703                         seq_printf(m, "%s", data->params[i]);
4704                 }
4705         }
4706 }
4707
4708 static void print_track_data_spec(struct seq_file *m,
4709                                   struct hist_trigger_data *hist_data,
4710                                   struct action_data *data)
4711 {
4712         if (data->handler == HANDLER_ONMAX)
4713                 seq_puts(m, ":onmax(");
4714         else if (data->handler == HANDLER_ONCHANGE)
4715                 seq_puts(m, ":onchange(");
4716         seq_printf(m, "%s", data->track_data.var_str);
4717         seq_printf(m, ").%s(", data->action_name);
4718
4719         print_action_spec(m, hist_data, data);
4720
4721         seq_puts(m, ")");
4722 }
4723
4724 static void print_onmatch_spec(struct seq_file *m,
4725                                struct hist_trigger_data *hist_data,
4726                                struct action_data *data)
4727 {
4728         seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
4729                    data->match_data.event);
4730
4731         seq_printf(m, "%s(", data->action_name);
4732
4733         print_action_spec(m, hist_data, data);
4734
4735         seq_puts(m, ")");
4736 }
4737
4738 static bool actions_match(struct hist_trigger_data *hist_data,
4739                           struct hist_trigger_data *hist_data_test)
4740 {
4741         unsigned int i, j;
4742
4743         if (hist_data->n_actions != hist_data_test->n_actions)
4744                 return false;
4745
4746         for (i = 0; i < hist_data->n_actions; i++) {
4747                 struct action_data *data = hist_data->actions[i];
4748                 struct action_data *data_test = hist_data_test->actions[i];
4749                 char *action_name, *action_name_test;
4750
4751                 if (data->handler != data_test->handler)
4752                         return false;
4753                 if (data->action != data_test->action)
4754                         return false;
4755
4756                 if (data->n_params != data_test->n_params)
4757                         return false;
4758
4759                 for (j = 0; j < data->n_params; j++) {
4760                         if (strcmp(data->params[j], data_test->params[j]) != 0)
4761                                 return false;
4762                 }
4763
4764                 if (data->use_trace_keyword)
4765                         action_name = data->synth_event_name;
4766                 else
4767                         action_name = data->action_name;
4768
4769                 if (data_test->use_trace_keyword)
4770                         action_name_test = data_test->synth_event_name;
4771                 else
4772                         action_name_test = data_test->action_name;
4773
4774                 if (strcmp(action_name, action_name_test) != 0)
4775                         return false;
4776
4777                 if (data->handler == HANDLER_ONMATCH) {
4778                         if (strcmp(data->match_data.event_system,
4779                                    data_test->match_data.event_system) != 0)
4780                                 return false;
4781                         if (strcmp(data->match_data.event,
4782                                    data_test->match_data.event) != 0)
4783                                 return false;
4784                 } else if (data->handler == HANDLER_ONMAX ||
4785                            data->handler == HANDLER_ONCHANGE) {
4786                         if (strcmp(data->track_data.var_str,
4787                                    data_test->track_data.var_str) != 0)
4788                                 return false;
4789                 }
4790         }
4791
4792         return true;
4793 }
4794
4795
4796 static void print_actions_spec(struct seq_file *m,
4797                                struct hist_trigger_data *hist_data)
4798 {
4799         unsigned int i;
4800
4801         for (i = 0; i < hist_data->n_actions; i++) {
4802                 struct action_data *data = hist_data->actions[i];
4803
4804                 if (data->handler == HANDLER_ONMATCH)
4805                         print_onmatch_spec(m, hist_data, data);
4806                 else if (data->handler == HANDLER_ONMAX ||
4807                          data->handler == HANDLER_ONCHANGE)
4808                         print_track_data_spec(m, hist_data, data);
4809         }
4810 }
4811
4812 static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
4813 {
4814         unsigned int i;
4815
4816         for (i = 0; i < hist_data->n_field_var_hists; i++) {
4817                 kfree(hist_data->field_var_hists[i]->cmd);
4818                 kfree(hist_data->field_var_hists[i]);
4819         }
4820 }
4821
4822 static void destroy_hist_data(struct hist_trigger_data *hist_data)
4823 {
4824         if (!hist_data)
4825                 return;
4826
4827         destroy_hist_trigger_attrs(hist_data->attrs);
4828         destroy_hist_fields(hist_data);
4829         tracing_map_destroy(hist_data->map);
4830
4831         destroy_actions(hist_data);
4832         destroy_field_vars(hist_data);
4833         destroy_field_var_hists(hist_data);
4834
4835         kfree(hist_data);
4836 }
4837
4838 static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
4839 {
4840         struct tracing_map *map = hist_data->map;
4841         struct ftrace_event_field *field;
4842         struct hist_field *hist_field;
4843         int i, idx = 0;
4844
4845         for_each_hist_field(i, hist_data) {
4846                 hist_field = hist_data->fields[i];
4847                 if (hist_field->flags & HIST_FIELD_FL_KEY) {
4848                         tracing_map_cmp_fn_t cmp_fn;
4849
4850                         field = hist_field->field;
4851
4852                         if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
4853                                 cmp_fn = tracing_map_cmp_none;
4854                         else if (!field || hist_field->flags & HIST_FIELD_FL_CPU)
4855                                 cmp_fn = tracing_map_cmp_num(hist_field->size,
4856                                                              hist_field->is_signed);
4857                         else if (is_string_field(field))
4858                                 cmp_fn = tracing_map_cmp_string;
4859                         else
4860                                 cmp_fn = tracing_map_cmp_num(field->size,
4861                                                              field->is_signed);
4862                         idx = tracing_map_add_key_field(map,
4863                                                         hist_field->offset,
4864                                                         cmp_fn);
4865                 } else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
4866                         idx = tracing_map_add_sum_field(map);
4867
4868                 if (idx < 0)
4869                         return idx;
4870
4871                 if (hist_field->flags & HIST_FIELD_FL_VAR) {
4872                         idx = tracing_map_add_var(map);
4873                         if (idx < 0)
4874                                 return idx;
4875                         hist_field->var.idx = idx;
4876                         hist_field->var.hist_data = hist_data;
4877                 }
4878         }
4879
4880         return 0;
4881 }
4882
4883 static struct hist_trigger_data *
4884 create_hist_data(unsigned int map_bits,
4885                  struct hist_trigger_attrs *attrs,
4886                  struct trace_event_file *file,
4887                  bool remove)
4888 {
4889         const struct tracing_map_ops *map_ops = NULL;
4890         struct hist_trigger_data *hist_data;
4891         int ret = 0;
4892
4893         hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
4894         if (!hist_data)
4895                 return ERR_PTR(-ENOMEM);
4896
4897         hist_data->attrs = attrs;
4898         hist_data->remove = remove;
4899         hist_data->event_file = file;
4900
4901         ret = parse_actions(hist_data);
4902         if (ret)
4903                 goto free;
4904
4905         ret = create_hist_fields(hist_data, file);
4906         if (ret)
4907                 goto free;
4908
4909         ret = create_sort_keys(hist_data);
4910         if (ret)
4911                 goto free;
4912
4913         map_ops = &hist_trigger_elt_data_ops;
4914
4915         hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
4916                                             map_ops, hist_data);
4917         if (IS_ERR(hist_data->map)) {
4918                 ret = PTR_ERR(hist_data->map);
4919                 hist_data->map = NULL;
4920                 goto free;
4921         }
4922
4923         ret = create_tracing_map_fields(hist_data);
4924         if (ret)
4925                 goto free;
4926  out:
4927         return hist_data;
4928  free:
4929         hist_data->attrs = NULL;
4930
4931         destroy_hist_data(hist_data);
4932
4933         hist_data = ERR_PTR(ret);
4934
4935         goto out;
4936 }
4937
4938 static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
4939                                     struct tracing_map_elt *elt,
4940                                     struct trace_buffer *buffer, void *rec,
4941                                     struct ring_buffer_event *rbe,
4942                                     u64 *var_ref_vals)
4943 {
4944         struct hist_elt_data *elt_data;
4945         struct hist_field *hist_field;
4946         unsigned int i, var_idx;
4947         u64 hist_val;
4948
4949         elt_data = elt->private_data;
4950         elt_data->var_ref_vals = var_ref_vals;
4951
4952         for_each_hist_val_field(i, hist_data) {
4953                 hist_field = hist_data->fields[i];
4954                 hist_val = hist_field->fn(hist_field, elt, buffer, rbe, rec);
4955                 if (hist_field->flags & HIST_FIELD_FL_VAR) {
4956                         var_idx = hist_field->var.idx;
4957
4958                         if (hist_field->flags & HIST_FIELD_FL_STRING) {
4959                                 unsigned int str_start, var_str_idx, idx;
4960                                 char *str, *val_str;
4961                                 unsigned int size;
4962
4963                                 str_start = hist_data->n_field_var_str +
4964                                         hist_data->n_save_var_str;
4965                                 var_str_idx = hist_field->var_str_idx;
4966                                 idx = str_start + var_str_idx;
4967
4968                                 str = elt_data->field_var_str[idx];
4969                                 val_str = (char *)(uintptr_t)hist_val;
4970
4971                                 size = min(hist_field->size, STR_VAR_LEN_MAX);
4972                                 strscpy(str, val_str, size);
4973
4974                                 hist_val = (u64)(uintptr_t)str;
4975                         }
4976                         tracing_map_set_var(elt, var_idx, hist_val);
4977                         continue;
4978                 }
4979                 tracing_map_update_sum(elt, i, hist_val);
4980         }
4981
4982         for_each_hist_key_field(i, hist_data) {
4983                 hist_field = hist_data->fields[i];
4984                 if (hist_field->flags & HIST_FIELD_FL_VAR) {
4985                         hist_val = hist_field->fn(hist_field, elt, buffer, rbe, rec);
4986                         var_idx = hist_field->var.idx;
4987                         tracing_map_set_var(elt, var_idx, hist_val);
4988                 }
4989         }
4990
4991         update_field_vars(hist_data, elt, buffer, rbe, rec);
4992 }
4993
4994 static inline void add_to_key(char *compound_key, void *key,
4995                               struct hist_field *key_field, void *rec)
4996 {
4997         size_t size = key_field->size;
4998
4999         if (key_field->flags & HIST_FIELD_FL_STRING) {
5000                 struct ftrace_event_field *field;
5001
5002                 field = key_field->field;
5003                 if (field->filter_type == FILTER_DYN_STRING ||
5004                     field->filter_type == FILTER_RDYN_STRING)
5005                         size = *(u32 *)(rec + field->offset) >> 16;
5006                 else if (field->filter_type == FILTER_STATIC_STRING)
5007                         size = field->size;
5008
5009                 /* ensure NULL-termination */
5010                 if (size > key_field->size - 1)
5011                         size = key_field->size - 1;
5012
5013                 strncpy(compound_key + key_field->offset, (char *)key, size);
5014         } else
5015                 memcpy(compound_key + key_field->offset, key, size);
5016 }
5017
5018 static void
5019 hist_trigger_actions(struct hist_trigger_data *hist_data,
5020                      struct tracing_map_elt *elt,
5021                      struct trace_buffer *buffer, void *rec,
5022                      struct ring_buffer_event *rbe, void *key,
5023                      u64 *var_ref_vals)
5024 {
5025         struct action_data *data;
5026         unsigned int i;
5027
5028         for (i = 0; i < hist_data->n_actions; i++) {
5029                 data = hist_data->actions[i];
5030                 data->fn(hist_data, elt, buffer, rec, rbe, key, data, var_ref_vals);
5031         }
5032 }
5033
5034 static void event_hist_trigger(struct event_trigger_data *data,
5035                                struct trace_buffer *buffer, void *rec,
5036                                struct ring_buffer_event *rbe)
5037 {
5038         struct hist_trigger_data *hist_data = data->private_data;
5039         bool use_compound_key = (hist_data->n_keys > 1);
5040         unsigned long entries[HIST_STACKTRACE_DEPTH];
5041         u64 var_ref_vals[TRACING_MAP_VARS_MAX];
5042         char compound_key[HIST_KEY_SIZE_MAX];
5043         struct tracing_map_elt *elt = NULL;
5044         struct hist_field *key_field;
5045         u64 field_contents;
5046         void *key = NULL;
5047         unsigned int i;
5048
5049         memset(compound_key, 0, hist_data->key_size);
5050
5051         for_each_hist_key_field(i, hist_data) {
5052                 key_field = hist_data->fields[i];
5053
5054                 if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5055                         memset(entries, 0, HIST_STACKTRACE_SIZE);
5056                         stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
5057                                          HIST_STACKTRACE_SKIP);
5058                         key = entries;
5059                 } else {
5060                         field_contents = key_field->fn(key_field, elt, buffer, rbe, rec);
5061                         if (key_field->flags & HIST_FIELD_FL_STRING) {
5062                                 key = (void *)(unsigned long)field_contents;
5063                                 use_compound_key = true;
5064                         } else
5065                                 key = (void *)&field_contents;
5066                 }
5067
5068                 if (use_compound_key)
5069                         add_to_key(compound_key, key, key_field, rec);
5070         }
5071
5072         if (use_compound_key)
5073                 key = compound_key;
5074
5075         if (hist_data->n_var_refs &&
5076             !resolve_var_refs(hist_data, key, var_ref_vals, false))
5077                 return;
5078
5079         elt = tracing_map_insert(hist_data->map, key);
5080         if (!elt)
5081                 return;
5082
5083         hist_trigger_elt_update(hist_data, elt, buffer, rec, rbe, var_ref_vals);
5084
5085         if (resolve_var_refs(hist_data, key, var_ref_vals, true))
5086                 hist_trigger_actions(hist_data, elt, buffer, rec, rbe, key, var_ref_vals);
5087 }
5088
5089 static void hist_trigger_stacktrace_print(struct seq_file *m,
5090                                           unsigned long *stacktrace_entries,
5091                                           unsigned int max_entries)
5092 {
5093         unsigned int spaces = 8;
5094         unsigned int i;
5095
5096         for (i = 0; i < max_entries; i++) {
5097                 if (!stacktrace_entries[i])
5098                         return;
5099
5100                 seq_printf(m, "%*c", 1 + spaces, ' ');
5101                 seq_printf(m, "%pS\n", (void*)stacktrace_entries[i]);
5102         }
5103 }
5104
5105 static void hist_trigger_print_key(struct seq_file *m,
5106                                    struct hist_trigger_data *hist_data,
5107                                    void *key,
5108                                    struct tracing_map_elt *elt)
5109 {
5110         struct hist_field *key_field;
5111         bool multiline = false;
5112         const char *field_name;
5113         unsigned int i;
5114         u64 uval;
5115
5116         seq_puts(m, "{ ");
5117
5118         for_each_hist_key_field(i, hist_data) {
5119                 key_field = hist_data->fields[i];
5120
5121                 if (i > hist_data->n_vals)
5122                         seq_puts(m, ", ");
5123
5124                 field_name = hist_field_name(key_field, 0);
5125
5126                 if (key_field->flags & HIST_FIELD_FL_HEX) {
5127                         uval = *(u64 *)(key + key_field->offset);
5128                         seq_printf(m, "%s: %llx", field_name, uval);
5129                 } else if (key_field->flags & HIST_FIELD_FL_SYM) {
5130                         uval = *(u64 *)(key + key_field->offset);
5131                         seq_printf(m, "%s: [%llx] %-45ps", field_name,
5132                                    uval, (void *)(uintptr_t)uval);
5133                 } else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
5134                         uval = *(u64 *)(key + key_field->offset);
5135                         seq_printf(m, "%s: [%llx] %-55pS", field_name,
5136                                    uval, (void *)(uintptr_t)uval);
5137                 } else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
5138                         struct hist_elt_data *elt_data = elt->private_data;
5139                         char *comm;
5140
5141                         if (WARN_ON_ONCE(!elt_data))
5142                                 return;
5143
5144                         comm = elt_data->comm;
5145
5146                         uval = *(u64 *)(key + key_field->offset);
5147                         seq_printf(m, "%s: %-16s[%10llu]", field_name,
5148                                    comm, uval);
5149                 } else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
5150                         const char *syscall_name;
5151
5152                         uval = *(u64 *)(key + key_field->offset);
5153                         syscall_name = get_syscall_name(uval);
5154                         if (!syscall_name)
5155                                 syscall_name = "unknown_syscall";
5156
5157                         seq_printf(m, "%s: %-30s[%3llu]", field_name,
5158                                    syscall_name, uval);
5159                 } else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5160                         seq_puts(m, "stacktrace:\n");
5161                         hist_trigger_stacktrace_print(m,
5162                                                       key + key_field->offset,
5163                                                       HIST_STACKTRACE_DEPTH);
5164                         multiline = true;
5165                 } else if (key_field->flags & HIST_FIELD_FL_LOG2) {
5166                         seq_printf(m, "%s: ~ 2^%-2llu", field_name,
5167                                    *(u64 *)(key + key_field->offset));
5168                 } else if (key_field->flags & HIST_FIELD_FL_BUCKET) {
5169                         unsigned long buckets = key_field->buckets;
5170                         uval = *(u64 *)(key + key_field->offset);
5171                         seq_printf(m, "%s: ~ %llu-%llu", field_name,
5172                                    uval, uval + buckets -1);
5173                 } else if (key_field->flags & HIST_FIELD_FL_STRING) {
5174                         seq_printf(m, "%s: %-50s", field_name,
5175                                    (char *)(key + key_field->offset));
5176                 } else {
5177                         uval = *(u64 *)(key + key_field->offset);
5178                         seq_printf(m, "%s: %10llu", field_name, uval);
5179                 }
5180         }
5181
5182         if (!multiline)
5183                 seq_puts(m, " ");
5184
5185         seq_puts(m, "}");
5186 }
5187
5188 static void hist_trigger_entry_print(struct seq_file *m,
5189                                      struct hist_trigger_data *hist_data,
5190                                      void *key,
5191                                      struct tracing_map_elt *elt)
5192 {
5193         const char *field_name;
5194         unsigned int i;
5195
5196         hist_trigger_print_key(m, hist_data, key, elt);
5197
5198         seq_printf(m, " hitcount: %10llu",
5199                    tracing_map_read_sum(elt, HITCOUNT_IDX));
5200
5201         for (i = 1; i < hist_data->n_vals; i++) {
5202                 field_name = hist_field_name(hist_data->fields[i], 0);
5203
5204                 if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR ||
5205                     hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR)
5206                         continue;
5207
5208                 if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
5209                         seq_printf(m, "  %s: %10llx", field_name,
5210                                    tracing_map_read_sum(elt, i));
5211                 } else {
5212                         seq_printf(m, "  %s: %10llu", field_name,
5213                                    tracing_map_read_sum(elt, i));
5214                 }
5215         }
5216
5217         print_actions(m, hist_data, elt);
5218
5219         seq_puts(m, "\n");
5220 }
5221
5222 static int print_entries(struct seq_file *m,
5223                          struct hist_trigger_data *hist_data)
5224 {
5225         struct tracing_map_sort_entry **sort_entries = NULL;
5226         struct tracing_map *map = hist_data->map;
5227         int i, n_entries;
5228
5229         n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
5230                                              hist_data->n_sort_keys,
5231                                              &sort_entries);
5232         if (n_entries < 0)
5233                 return n_entries;
5234
5235         for (i = 0; i < n_entries; i++)
5236                 hist_trigger_entry_print(m, hist_data,
5237                                          sort_entries[i]->key,
5238                                          sort_entries[i]->elt);
5239
5240         tracing_map_destroy_sort_entries(sort_entries, n_entries);
5241
5242         return n_entries;
5243 }
5244
5245 static void hist_trigger_show(struct seq_file *m,
5246                               struct event_trigger_data *data, int n)
5247 {
5248         struct hist_trigger_data *hist_data;
5249         int n_entries;
5250
5251         if (n > 0)
5252                 seq_puts(m, "\n\n");
5253
5254         seq_puts(m, "# event histogram\n#\n# trigger info: ");
5255         data->ops->print(m, data->ops, data);
5256         seq_puts(m, "#\n\n");
5257
5258         hist_data = data->private_data;
5259         n_entries = print_entries(m, hist_data);
5260         if (n_entries < 0)
5261                 n_entries = 0;
5262
5263         track_data_snapshot_print(m, hist_data);
5264
5265         seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
5266                    (u64)atomic64_read(&hist_data->map->hits),
5267                    n_entries, (u64)atomic64_read(&hist_data->map->drops));
5268 }
5269
5270 static int hist_show(struct seq_file *m, void *v)
5271 {
5272         struct event_trigger_data *data;
5273         struct trace_event_file *event_file;
5274         int n = 0, ret = 0;
5275
5276         mutex_lock(&event_mutex);
5277
5278         event_file = event_file_data(m->private);
5279         if (unlikely(!event_file)) {
5280                 ret = -ENODEV;
5281                 goto out_unlock;
5282         }
5283
5284         list_for_each_entry(data, &event_file->triggers, list) {
5285                 if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5286                         hist_trigger_show(m, data, n++);
5287         }
5288
5289  out_unlock:
5290         mutex_unlock(&event_mutex);
5291
5292         return ret;
5293 }
5294
5295 static int event_hist_open(struct inode *inode, struct file *file)
5296 {
5297         int ret;
5298
5299         ret = security_locked_down(LOCKDOWN_TRACEFS);
5300         if (ret)
5301                 return ret;
5302
5303         return single_open(file, hist_show, file);
5304 }
5305
5306 const struct file_operations event_hist_fops = {
5307         .open = event_hist_open,
5308         .read = seq_read,
5309         .llseek = seq_lseek,
5310         .release = single_release,
5311 };
5312
5313 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
5314 static void hist_field_debug_show_flags(struct seq_file *m,
5315                                         unsigned long flags)
5316 {
5317         seq_puts(m, "      flags:\n");
5318
5319         if (flags & HIST_FIELD_FL_KEY)
5320                 seq_puts(m, "        HIST_FIELD_FL_KEY\n");
5321         else if (flags & HIST_FIELD_FL_HITCOUNT)
5322                 seq_puts(m, "        VAL: HIST_FIELD_FL_HITCOUNT\n");
5323         else if (flags & HIST_FIELD_FL_VAR)
5324                 seq_puts(m, "        HIST_FIELD_FL_VAR\n");
5325         else if (flags & HIST_FIELD_FL_VAR_REF)
5326                 seq_puts(m, "        HIST_FIELD_FL_VAR_REF\n");
5327         else
5328                 seq_puts(m, "        VAL: normal u64 value\n");
5329
5330         if (flags & HIST_FIELD_FL_ALIAS)
5331                 seq_puts(m, "        HIST_FIELD_FL_ALIAS\n");
5332         else if (flags & HIST_FIELD_FL_CONST)
5333                 seq_puts(m, "        HIST_FIELD_FL_CONST\n");
5334 }
5335
5336 static int hist_field_debug_show(struct seq_file *m,
5337                                  struct hist_field *field, unsigned long flags)
5338 {
5339         if ((field->flags & flags) != flags) {
5340                 seq_printf(m, "ERROR: bad flags - %lx\n", flags);
5341                 return -EINVAL;
5342         }
5343
5344         hist_field_debug_show_flags(m, field->flags);
5345         if (field->field)
5346                 seq_printf(m, "      ftrace_event_field name: %s\n",
5347                            field->field->name);
5348
5349         if (field->flags & HIST_FIELD_FL_VAR) {
5350                 seq_printf(m, "      var.name: %s\n", field->var.name);
5351                 seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5352                            field->var.idx);
5353         }
5354
5355         if (field->flags & HIST_FIELD_FL_CONST)
5356                 seq_printf(m, "      constant: %llu\n", field->constant);
5357
5358         if (field->flags & HIST_FIELD_FL_ALIAS)
5359                 seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5360                            field->var_ref_idx);
5361
5362         if (field->flags & HIST_FIELD_FL_VAR_REF) {
5363                 seq_printf(m, "      name: %s\n", field->name);
5364                 seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5365                            field->var.idx);
5366                 seq_printf(m, "      var.hist_data: %p\n", field->var.hist_data);
5367                 seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5368                            field->var_ref_idx);
5369                 if (field->system)
5370                         seq_printf(m, "      system: %s\n", field->system);
5371                 if (field->event_name)
5372                         seq_printf(m, "      event_name: %s\n", field->event_name);
5373         }
5374
5375         seq_printf(m, "      type: %s\n", field->type);
5376         seq_printf(m, "      size: %u\n", field->size);
5377         seq_printf(m, "      is_signed: %u\n", field->is_signed);
5378
5379         return 0;
5380 }
5381
5382 static int field_var_debug_show(struct seq_file *m,
5383                                 struct field_var *field_var, unsigned int i,
5384                                 bool save_vars)
5385 {
5386         const char *vars_name = save_vars ? "save_vars" : "field_vars";
5387         struct hist_field *field;
5388         int ret = 0;
5389
5390         seq_printf(m, "\n    hist_data->%s[%d]:\n", vars_name, i);
5391
5392         field = field_var->var;
5393
5394         seq_printf(m, "\n      %s[%d].var:\n", vars_name, i);
5395
5396         hist_field_debug_show_flags(m, field->flags);
5397         seq_printf(m, "      var.name: %s\n", field->var.name);
5398         seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5399                    field->var.idx);
5400
5401         field = field_var->val;
5402
5403         seq_printf(m, "\n      %s[%d].val:\n", vars_name, i);
5404         if (field->field)
5405                 seq_printf(m, "      ftrace_event_field name: %s\n",
5406                            field->field->name);
5407         else {
5408                 ret = -EINVAL;
5409                 goto out;
5410         }
5411
5412         seq_printf(m, "      type: %s\n", field->type);
5413         seq_printf(m, "      size: %u\n", field->size);
5414         seq_printf(m, "      is_signed: %u\n", field->is_signed);
5415 out:
5416         return ret;
5417 }
5418
5419 static int hist_action_debug_show(struct seq_file *m,
5420                                   struct action_data *data, int i)
5421 {
5422         int ret = 0;
5423
5424         if (data->handler == HANDLER_ONMAX ||
5425             data->handler == HANDLER_ONCHANGE) {
5426                 seq_printf(m, "\n    hist_data->actions[%d].track_data.var_ref:\n", i);
5427                 ret = hist_field_debug_show(m, data->track_data.var_ref,
5428                                             HIST_FIELD_FL_VAR_REF);
5429                 if (ret)
5430                         goto out;
5431
5432                 seq_printf(m, "\n    hist_data->actions[%d].track_data.track_var:\n", i);
5433                 ret = hist_field_debug_show(m, data->track_data.track_var,
5434                                             HIST_FIELD_FL_VAR);
5435                 if (ret)
5436                         goto out;
5437         }
5438
5439         if (data->handler == HANDLER_ONMATCH) {
5440                 seq_printf(m, "\n    hist_data->actions[%d].match_data.event_system: %s\n",
5441                            i, data->match_data.event_system);
5442                 seq_printf(m, "    hist_data->actions[%d].match_data.event: %s\n",
5443                            i, data->match_data.event);
5444         }
5445 out:
5446         return ret;
5447 }
5448
5449 static int hist_actions_debug_show(struct seq_file *m,
5450                                    struct hist_trigger_data *hist_data)
5451 {
5452         int i, ret = 0;
5453
5454         if (hist_data->n_actions)
5455                 seq_puts(m, "\n  action tracking variables (for onmax()/onchange()/onmatch()):\n");
5456
5457         for (i = 0; i < hist_data->n_actions; i++) {
5458                 struct action_data *action = hist_data->actions[i];
5459
5460                 ret = hist_action_debug_show(m, action, i);
5461                 if (ret)
5462                         goto out;
5463         }
5464
5465         if (hist_data->n_save_vars)
5466                 seq_puts(m, "\n  save action variables (save() params):\n");
5467
5468         for (i = 0; i < hist_data->n_save_vars; i++) {
5469                 ret = field_var_debug_show(m, hist_data->save_vars[i], i, true);
5470                 if (ret)
5471                         goto out;
5472         }
5473 out:
5474         return ret;
5475 }
5476
5477 static void hist_trigger_debug_show(struct seq_file *m,
5478                                     struct event_trigger_data *data, int n)
5479 {
5480         struct hist_trigger_data *hist_data;
5481         int i, ret;
5482
5483         if (n > 0)
5484                 seq_puts(m, "\n\n");
5485
5486         seq_puts(m, "# event histogram\n#\n# trigger info: ");
5487         data->ops->print(m, data->ops, data);
5488         seq_puts(m, "#\n\n");
5489
5490         hist_data = data->private_data;
5491
5492         seq_printf(m, "hist_data: %p\n\n", hist_data);
5493         seq_printf(m, "  n_vals: %u\n", hist_data->n_vals);
5494         seq_printf(m, "  n_keys: %u\n", hist_data->n_keys);
5495         seq_printf(m, "  n_fields: %u\n", hist_data->n_fields);
5496
5497         seq_puts(m, "\n  val fields:\n\n");
5498
5499         seq_puts(m, "    hist_data->fields[0]:\n");
5500         ret = hist_field_debug_show(m, hist_data->fields[0],
5501                                     HIST_FIELD_FL_HITCOUNT);
5502         if (ret)
5503                 return;
5504
5505         for (i = 1; i < hist_data->n_vals; i++) {
5506                 seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
5507                 ret = hist_field_debug_show(m, hist_data->fields[i], 0);
5508                 if (ret)
5509                         return;
5510         }
5511
5512         seq_puts(m, "\n  key fields:\n");
5513
5514         for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
5515                 seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
5516                 ret = hist_field_debug_show(m, hist_data->fields[i],
5517                                             HIST_FIELD_FL_KEY);
5518                 if (ret)
5519                         return;
5520         }
5521
5522         if (hist_data->n_var_refs)
5523                 seq_puts(m, "\n  variable reference fields:\n");
5524
5525         for (i = 0; i < hist_data->n_var_refs; i++) {
5526                 seq_printf(m, "\n    hist_data->var_refs[%d]:\n", i);
5527                 ret = hist_field_debug_show(m, hist_data->var_refs[i],
5528                                             HIST_FIELD_FL_VAR_REF);
5529                 if (ret)
5530                         return;
5531         }
5532
5533         if (hist_data->n_field_vars)
5534                 seq_puts(m, "\n  field variables:\n");
5535
5536         for (i = 0; i < hist_data->n_field_vars; i++) {
5537                 ret = field_var_debug_show(m, hist_data->field_vars[i], i, false);
5538                 if (ret)
5539                         return;
5540         }
5541
5542         ret = hist_actions_debug_show(m, hist_data);
5543         if (ret)
5544                 return;
5545 }
5546
5547 static int hist_debug_show(struct seq_file *m, void *v)
5548 {
5549         struct event_trigger_data *data;
5550         struct trace_event_file *event_file;
5551         int n = 0, ret = 0;
5552
5553         mutex_lock(&event_mutex);
5554
5555         event_file = event_file_data(m->private);
5556         if (unlikely(!event_file)) {
5557                 ret = -ENODEV;
5558                 goto out_unlock;
5559         }
5560
5561         list_for_each_entry(data, &event_file->triggers, list) {
5562                 if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5563                         hist_trigger_debug_show(m, data, n++);
5564         }
5565
5566  out_unlock:
5567         mutex_unlock(&event_mutex);
5568
5569         return ret;
5570 }
5571
5572 static int event_hist_debug_open(struct inode *inode, struct file *file)
5573 {
5574         int ret;
5575
5576         ret = security_locked_down(LOCKDOWN_TRACEFS);
5577         if (ret)
5578                 return ret;
5579
5580         return single_open(file, hist_debug_show, file);
5581 }
5582
5583 const struct file_operations event_hist_debug_fops = {
5584         .open = event_hist_debug_open,
5585         .read = seq_read,
5586         .llseek = seq_lseek,
5587         .release = single_release,
5588 };
5589 #endif
5590
5591 static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
5592 {
5593         const char *field_name = hist_field_name(hist_field, 0);
5594
5595         if (hist_field->var.name)
5596                 seq_printf(m, "%s=", hist_field->var.name);
5597
5598         if (hist_field->flags & HIST_FIELD_FL_CPU)
5599                 seq_puts(m, "common_cpu");
5600         else if (hist_field->flags & HIST_FIELD_FL_CONST)
5601                 seq_printf(m, "%llu", hist_field->constant);
5602         else if (field_name) {
5603                 if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
5604                     hist_field->flags & HIST_FIELD_FL_ALIAS)
5605                         seq_putc(m, '$');
5606                 seq_printf(m, "%s", field_name);
5607         } else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
5608                 seq_puts(m, "common_timestamp");
5609
5610         if (hist_field->flags) {
5611                 if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
5612                     !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
5613                         const char *flags = get_hist_field_flags(hist_field);
5614
5615                         if (flags)
5616                                 seq_printf(m, ".%s", flags);
5617                 }
5618         }
5619         if (hist_field->buckets)
5620                 seq_printf(m, "=%ld", hist_field->buckets);
5621 }
5622
5623 static int event_hist_trigger_print(struct seq_file *m,
5624                                     struct event_trigger_ops *ops,
5625                                     struct event_trigger_data *data)
5626 {
5627         struct hist_trigger_data *hist_data = data->private_data;
5628         struct hist_field *field;
5629         bool have_var = false;
5630         unsigned int i;
5631
5632         seq_puts(m, HIST_PREFIX);
5633
5634         if (data->name)
5635                 seq_printf(m, "%s:", data->name);
5636
5637         seq_puts(m, "keys=");
5638
5639         for_each_hist_key_field(i, hist_data) {
5640                 field = hist_data->fields[i];
5641
5642                 if (i > hist_data->n_vals)
5643                         seq_puts(m, ",");
5644
5645                 if (field->flags & HIST_FIELD_FL_STACKTRACE)
5646                         seq_puts(m, "stacktrace");
5647                 else
5648                         hist_field_print(m, field);
5649         }
5650
5651         seq_puts(m, ":vals=");
5652
5653         for_each_hist_val_field(i, hist_data) {
5654                 field = hist_data->fields[i];
5655                 if (field->flags & HIST_FIELD_FL_VAR) {
5656                         have_var = true;
5657                         continue;
5658                 }
5659
5660                 if (i == HITCOUNT_IDX)
5661                         seq_puts(m, "hitcount");
5662                 else {
5663                         seq_puts(m, ",");
5664                         hist_field_print(m, field);
5665                 }
5666         }
5667
5668         if (have_var) {
5669                 unsigned int n = 0;
5670
5671                 seq_puts(m, ":");
5672
5673                 for_each_hist_val_field(i, hist_data) {
5674                         field = hist_data->fields[i];
5675
5676                         if (field->flags & HIST_FIELD_FL_VAR) {
5677                                 if (n++)
5678                                         seq_puts(m, ",");
5679                                 hist_field_print(m, field);
5680                         }
5681                 }
5682         }
5683
5684         seq_puts(m, ":sort=");
5685
5686         for (i = 0; i < hist_data->n_sort_keys; i++) {
5687                 struct tracing_map_sort_key *sort_key;
5688                 unsigned int idx, first_key_idx;
5689
5690                 /* skip VAR vals */
5691                 first_key_idx = hist_data->n_vals - hist_data->n_vars;
5692
5693                 sort_key = &hist_data->sort_keys[i];
5694                 idx = sort_key->field_idx;
5695
5696                 if (WARN_ON(idx >= HIST_FIELDS_MAX))
5697                         return -EINVAL;
5698
5699                 if (i > 0)
5700                         seq_puts(m, ",");
5701
5702                 if (idx == HITCOUNT_IDX)
5703                         seq_puts(m, "hitcount");
5704                 else {
5705                         if (idx >= first_key_idx)
5706                                 idx += hist_data->n_vars;
5707                         hist_field_print(m, hist_data->fields[idx]);
5708                 }
5709
5710                 if (sort_key->descending)
5711                         seq_puts(m, ".descending");
5712         }
5713         seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
5714         if (hist_data->enable_timestamps)
5715                 seq_printf(m, ":clock=%s", hist_data->attrs->clock);
5716
5717         print_actions_spec(m, hist_data);
5718
5719         if (data->filter_str)
5720                 seq_printf(m, " if %s", data->filter_str);
5721
5722         if (data->paused)
5723                 seq_puts(m, " [paused]");
5724         else
5725                 seq_puts(m, " [active]");
5726
5727         seq_putc(m, '\n');
5728
5729         return 0;
5730 }
5731
5732 static int event_hist_trigger_init(struct event_trigger_ops *ops,
5733                                    struct event_trigger_data *data)
5734 {
5735         struct hist_trigger_data *hist_data = data->private_data;
5736
5737         if (!data->ref && hist_data->attrs->name)
5738                 save_named_trigger(hist_data->attrs->name, data);
5739
5740         data->ref++;
5741
5742         return 0;
5743 }
5744
5745 static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
5746 {
5747         struct trace_event_file *file;
5748         unsigned int i;
5749         char *cmd;
5750         int ret;
5751
5752         for (i = 0; i < hist_data->n_field_var_hists; i++) {
5753                 file = hist_data->field_var_hists[i]->hist_data->event_file;
5754                 cmd = hist_data->field_var_hists[i]->cmd;
5755                 ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
5756                                                "!hist", "hist", cmd);
5757                 WARN_ON_ONCE(ret < 0);
5758         }
5759 }
5760
5761 static void event_hist_trigger_free(struct event_trigger_ops *ops,
5762                                     struct event_trigger_data *data)
5763 {
5764         struct hist_trigger_data *hist_data = data->private_data;
5765
5766         if (WARN_ON_ONCE(data->ref <= 0))
5767                 return;
5768
5769         data->ref--;
5770         if (!data->ref) {
5771                 if (data->name)
5772                         del_named_trigger(data);
5773
5774                 trigger_data_free(data);
5775
5776                 remove_hist_vars(hist_data);
5777
5778                 unregister_field_var_hists(hist_data);
5779
5780                 destroy_hist_data(hist_data);
5781         }
5782 }
5783
5784 static struct event_trigger_ops event_hist_trigger_ops = {
5785         .trigger                = event_hist_trigger,
5786         .print                  = event_hist_trigger_print,
5787         .init                   = event_hist_trigger_init,
5788         .free                   = event_hist_trigger_free,
5789 };
5790
5791 static int event_hist_trigger_named_init(struct event_trigger_ops *ops,
5792                                          struct event_trigger_data *data)
5793 {
5794         data->ref++;
5795
5796         save_named_trigger(data->named_data->name, data);
5797
5798         event_hist_trigger_init(ops, data->named_data);
5799
5800         return 0;
5801 }
5802
5803 static void event_hist_trigger_named_free(struct event_trigger_ops *ops,
5804                                           struct event_trigger_data *data)
5805 {
5806         if (WARN_ON_ONCE(data->ref <= 0))
5807                 return;
5808
5809         event_hist_trigger_free(ops, data->named_data);
5810
5811         data->ref--;
5812         if (!data->ref) {
5813                 del_named_trigger(data);
5814                 trigger_data_free(data);
5815         }
5816 }
5817
5818 static struct event_trigger_ops event_hist_trigger_named_ops = {
5819         .trigger                = event_hist_trigger,
5820         .print                  = event_hist_trigger_print,
5821         .init                   = event_hist_trigger_named_init,
5822         .free                   = event_hist_trigger_named_free,
5823 };
5824
5825 static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
5826                                                             char *param)
5827 {
5828         return &event_hist_trigger_ops;
5829 }
5830
5831 static void hist_clear(struct event_trigger_data *data)
5832 {
5833         struct hist_trigger_data *hist_data = data->private_data;
5834
5835         if (data->name)
5836                 pause_named_trigger(data);
5837
5838         tracepoint_synchronize_unregister();
5839
5840         tracing_map_clear(hist_data->map);
5841
5842         if (data->name)
5843                 unpause_named_trigger(data);
5844 }
5845
5846 static bool compatible_field(struct ftrace_event_field *field,
5847                              struct ftrace_event_field *test_field)
5848 {
5849         if (field == test_field)
5850                 return true;
5851         if (field == NULL || test_field == NULL)
5852                 return false;
5853         if (strcmp(field->name, test_field->name) != 0)
5854                 return false;
5855         if (strcmp(field->type, test_field->type) != 0)
5856                 return false;
5857         if (field->size != test_field->size)
5858                 return false;
5859         if (field->is_signed != test_field->is_signed)
5860                 return false;
5861
5862         return true;
5863 }
5864
5865 static bool hist_trigger_match(struct event_trigger_data *data,
5866                                struct event_trigger_data *data_test,
5867                                struct event_trigger_data *named_data,
5868                                bool ignore_filter)
5869 {
5870         struct tracing_map_sort_key *sort_key, *sort_key_test;
5871         struct hist_trigger_data *hist_data, *hist_data_test;
5872         struct hist_field *key_field, *key_field_test;
5873         unsigned int i;
5874
5875         if (named_data && (named_data != data_test) &&
5876             (named_data != data_test->named_data))
5877                 return false;
5878
5879         if (!named_data && is_named_trigger(data_test))
5880                 return false;
5881
5882         hist_data = data->private_data;
5883         hist_data_test = data_test->private_data;
5884
5885         if (hist_data->n_vals != hist_data_test->n_vals ||
5886             hist_data->n_fields != hist_data_test->n_fields ||
5887             hist_data->n_sort_keys != hist_data_test->n_sort_keys)
5888                 return false;
5889
5890         if (!ignore_filter) {
5891                 if ((data->filter_str && !data_test->filter_str) ||
5892                    (!data->filter_str && data_test->filter_str))
5893                         return false;
5894         }
5895
5896         for_each_hist_field(i, hist_data) {
5897                 key_field = hist_data->fields[i];
5898                 key_field_test = hist_data_test->fields[i];
5899
5900                 if (key_field->flags != key_field_test->flags)
5901                         return false;
5902                 if (!compatible_field(key_field->field, key_field_test->field))
5903                         return false;
5904                 if (key_field->offset != key_field_test->offset)
5905                         return false;
5906                 if (key_field->size != key_field_test->size)
5907                         return false;
5908                 if (key_field->is_signed != key_field_test->is_signed)
5909                         return false;
5910                 if (!!key_field->var.name != !!key_field_test->var.name)
5911                         return false;
5912                 if (key_field->var.name &&
5913                     strcmp(key_field->var.name, key_field_test->var.name) != 0)
5914                         return false;
5915         }
5916
5917         for (i = 0; i < hist_data->n_sort_keys; i++) {
5918                 sort_key = &hist_data->sort_keys[i];
5919                 sort_key_test = &hist_data_test->sort_keys[i];
5920
5921                 if (sort_key->field_idx != sort_key_test->field_idx ||
5922                     sort_key->descending != sort_key_test->descending)
5923                         return false;
5924         }
5925
5926         if (!ignore_filter && data->filter_str &&
5927             (strcmp(data->filter_str, data_test->filter_str) != 0))
5928                 return false;
5929
5930         if (!actions_match(hist_data, hist_data_test))
5931                 return false;
5932
5933         return true;
5934 }
5935
5936 static int hist_register_trigger(char *glob,
5937                                  struct event_trigger_data *data,
5938                                  struct trace_event_file *file)
5939 {
5940         struct hist_trigger_data *hist_data = data->private_data;
5941         struct event_trigger_data *test, *named_data = NULL;
5942         struct trace_array *tr = file->tr;
5943         int ret = 0;
5944
5945         if (hist_data->attrs->name) {
5946                 named_data = find_named_trigger(hist_data->attrs->name);
5947                 if (named_data) {
5948                         if (!hist_trigger_match(data, named_data, named_data,
5949                                                 true)) {
5950                                 hist_err(tr, HIST_ERR_NAMED_MISMATCH, errpos(hist_data->attrs->name));
5951                                 ret = -EINVAL;
5952                                 goto out;
5953                         }
5954                 }
5955         }
5956
5957         if (hist_data->attrs->name && !named_data)
5958                 goto new;
5959
5960         lockdep_assert_held(&event_mutex);
5961
5962         list_for_each_entry(test, &file->triggers, list) {
5963                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5964                         if (!hist_trigger_match(data, test, named_data, false))
5965                                 continue;
5966                         if (hist_data->attrs->pause)
5967                                 test->paused = true;
5968                         else if (hist_data->attrs->cont)
5969                                 test->paused = false;
5970                         else if (hist_data->attrs->clear)
5971                                 hist_clear(test);
5972                         else {
5973                                 hist_err(tr, HIST_ERR_TRIGGER_EEXIST, 0);
5974                                 ret = -EEXIST;
5975                         }
5976                         goto out;
5977                 }
5978         }
5979  new:
5980         if (hist_data->attrs->cont || hist_data->attrs->clear) {
5981                 hist_err(tr, HIST_ERR_TRIGGER_ENOENT_CLEAR, 0);
5982                 ret = -ENOENT;
5983                 goto out;
5984         }
5985
5986         if (hist_data->attrs->pause)
5987                 data->paused = true;
5988
5989         if (named_data) {
5990                 data->private_data = named_data->private_data;
5991                 set_named_trigger_data(data, named_data);
5992                 data->ops = &event_hist_trigger_named_ops;
5993         }
5994
5995         if (data->ops->init) {
5996                 ret = data->ops->init(data->ops, data);
5997                 if (ret < 0)
5998                         goto out;
5999         }
6000
6001         if (hist_data->enable_timestamps) {
6002                 char *clock = hist_data->attrs->clock;
6003
6004                 ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
6005                 if (ret) {
6006                         hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
6007                         goto out;
6008                 }
6009
6010                 tracing_set_filter_buffering(file->tr, true);
6011         }
6012
6013         if (named_data)
6014                 destroy_hist_data(hist_data);
6015
6016         ret++;
6017  out:
6018         return ret;
6019 }
6020
6021 static int hist_trigger_enable(struct event_trigger_data *data,
6022                                struct trace_event_file *file)
6023 {
6024         int ret = 0;
6025
6026         list_add_tail_rcu(&data->list, &file->triggers);
6027
6028         update_cond_flag(file);
6029
6030         if (trace_event_trigger_enable_disable(file, 1) < 0) {
6031                 list_del_rcu(&data->list);
6032                 update_cond_flag(file);
6033                 ret--;
6034         }
6035
6036         return ret;
6037 }
6038
6039 static bool have_hist_trigger_match(struct event_trigger_data *data,
6040                                     struct trace_event_file *file)
6041 {
6042         struct hist_trigger_data *hist_data = data->private_data;
6043         struct event_trigger_data *test, *named_data = NULL;
6044         bool match = false;
6045
6046         lockdep_assert_held(&event_mutex);
6047
6048         if (hist_data->attrs->name)
6049                 named_data = find_named_trigger(hist_data->attrs->name);
6050
6051         list_for_each_entry(test, &file->triggers, list) {
6052                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6053                         if (hist_trigger_match(data, test, named_data, false)) {
6054                                 match = true;
6055                                 break;
6056                         }
6057                 }
6058         }
6059
6060         return match;
6061 }
6062
6063 static bool hist_trigger_check_refs(struct event_trigger_data *data,
6064                                     struct trace_event_file *file)
6065 {
6066         struct hist_trigger_data *hist_data = data->private_data;
6067         struct event_trigger_data *test, *named_data = NULL;
6068
6069         lockdep_assert_held(&event_mutex);
6070
6071         if (hist_data->attrs->name)
6072                 named_data = find_named_trigger(hist_data->attrs->name);
6073
6074         list_for_each_entry(test, &file->triggers, list) {
6075                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6076                         if (!hist_trigger_match(data, test, named_data, false))
6077                                 continue;
6078                         hist_data = test->private_data;
6079                         if (check_var_refs(hist_data))
6080                                 return true;
6081                         break;
6082                 }
6083         }
6084
6085         return false;
6086 }
6087
6088 static void hist_unregister_trigger(char *glob,
6089                                     struct event_trigger_data *data,
6090                                     struct trace_event_file *file)
6091 {
6092         struct hist_trigger_data *hist_data = data->private_data;
6093         struct event_trigger_data *test, *named_data = NULL;
6094         bool unregistered = false;
6095
6096         lockdep_assert_held(&event_mutex);
6097
6098         if (hist_data->attrs->name)
6099                 named_data = find_named_trigger(hist_data->attrs->name);
6100
6101         list_for_each_entry(test, &file->triggers, list) {
6102                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6103                         if (!hist_trigger_match(data, test, named_data, false))
6104                                 continue;
6105                         unregistered = true;
6106                         list_del_rcu(&test->list);
6107                         trace_event_trigger_enable_disable(file, 0);
6108                         update_cond_flag(file);
6109                         break;
6110                 }
6111         }
6112
6113         if (unregistered && test->ops->free)
6114                 test->ops->free(test->ops, test);
6115
6116         if (hist_data->enable_timestamps) {
6117                 if (!hist_data->remove || unregistered)
6118                         tracing_set_filter_buffering(file->tr, false);
6119         }
6120 }
6121
6122 static bool hist_file_check_refs(struct trace_event_file *file)
6123 {
6124         struct hist_trigger_data *hist_data;
6125         struct event_trigger_data *test;
6126
6127         lockdep_assert_held(&event_mutex);
6128
6129         list_for_each_entry(test, &file->triggers, list) {
6130                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6131                         hist_data = test->private_data;
6132                         if (check_var_refs(hist_data))
6133                                 return true;
6134                 }
6135         }
6136
6137         return false;
6138 }
6139
6140 static void hist_unreg_all(struct trace_event_file *file)
6141 {
6142         struct event_trigger_data *test, *n;
6143         struct hist_trigger_data *hist_data;
6144         struct synth_event *se;
6145         const char *se_name;
6146
6147         lockdep_assert_held(&event_mutex);
6148
6149         if (hist_file_check_refs(file))
6150                 return;
6151
6152         list_for_each_entry_safe(test, n, &file->triggers, list) {
6153                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6154                         hist_data = test->private_data;
6155                         list_del_rcu(&test->list);
6156                         trace_event_trigger_enable_disable(file, 0);
6157
6158                         se_name = trace_event_name(file->event_call);
6159                         se = find_synth_event(se_name);
6160                         if (se)
6161                                 se->ref--;
6162
6163                         update_cond_flag(file);
6164                         if (hist_data->enable_timestamps)
6165                                 tracing_set_filter_buffering(file->tr, false);
6166                         if (test->ops->free)
6167                                 test->ops->free(test->ops, test);
6168                 }
6169         }
6170 }
6171
6172 static int event_hist_trigger_parse(struct event_command *cmd_ops,
6173                                     struct trace_event_file *file,
6174                                     char *glob, char *cmd, char *param)
6175 {
6176         unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
6177         struct event_trigger_data *trigger_data;
6178         struct hist_trigger_attrs *attrs;
6179         struct event_trigger_ops *trigger_ops;
6180         struct hist_trigger_data *hist_data;
6181         struct synth_event *se;
6182         const char *se_name;
6183         bool remove = false;
6184         char *trigger, *p, *start;
6185         int ret = 0;
6186
6187         lockdep_assert_held(&event_mutex);
6188
6189         WARN_ON(!glob);
6190
6191         if (strlen(glob)) {
6192                 hist_err_clear();
6193                 last_cmd_set(file, param);
6194         }
6195
6196         if (!param)
6197                 return -EINVAL;
6198
6199         if (glob[0] == '!')
6200                 remove = true;
6201
6202         /*
6203          * separate the trigger from the filter (k:v [if filter])
6204          * allowing for whitespace in the trigger
6205          */
6206         p = trigger = param;
6207         do {
6208                 p = strstr(p, "if");
6209                 if (!p)
6210                         break;
6211                 if (p == param)
6212                         return -EINVAL;
6213                 if (*(p - 1) != ' ' && *(p - 1) != '\t') {
6214                         p++;
6215                         continue;
6216                 }
6217                 if (p >= param + strlen(param) - (sizeof("if") - 1) - 1)
6218                         return -EINVAL;
6219                 if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
6220                         p++;
6221                         continue;
6222                 }
6223                 break;
6224         } while (1);
6225
6226         if (!p)
6227                 param = NULL;
6228         else {
6229                 *(p - 1) = '\0';
6230                 param = strstrip(p);
6231                 trigger = strstrip(trigger);
6232         }
6233
6234         /*
6235          * To simplify arithmetic expression parsing, replace occurrences of
6236          * '.sym-offset' modifier with '.symXoffset'
6237          */
6238         start = strstr(trigger, ".sym-offset");
6239         while (start) {
6240                 *(start + 4) = 'X';
6241                 start = strstr(start + 11, ".sym-offset");
6242         }
6243
6244         attrs = parse_hist_trigger_attrs(file->tr, trigger);
6245         if (IS_ERR(attrs))
6246                 return PTR_ERR(attrs);
6247
6248         if (attrs->map_bits)
6249                 hist_trigger_bits = attrs->map_bits;
6250
6251         hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
6252         if (IS_ERR(hist_data)) {
6253                 destroy_hist_trigger_attrs(attrs);
6254                 return PTR_ERR(hist_data);
6255         }
6256
6257         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
6258
6259         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
6260         if (!trigger_data) {
6261                 ret = -ENOMEM;
6262                 goto out_free;
6263         }
6264
6265         trigger_data->count = -1;
6266         trigger_data->ops = trigger_ops;
6267         trigger_data->cmd_ops = cmd_ops;
6268
6269         INIT_LIST_HEAD(&trigger_data->list);
6270         RCU_INIT_POINTER(trigger_data->filter, NULL);
6271
6272         trigger_data->private_data = hist_data;
6273
6274         /* if param is non-empty, it's supposed to be a filter */
6275         if (param && cmd_ops->set_filter) {
6276                 ret = cmd_ops->set_filter(param, trigger_data, file);
6277                 if (ret < 0)
6278                         goto out_free;
6279         }
6280
6281         if (remove) {
6282                 if (!have_hist_trigger_match(trigger_data, file))
6283                         goto out_free;
6284
6285                 if (hist_trigger_check_refs(trigger_data, file)) {
6286                         ret = -EBUSY;
6287                         goto out_free;
6288                 }
6289
6290                 cmd_ops->unreg(glob+1, trigger_data, file);
6291                 se_name = trace_event_name(file->event_call);
6292                 se = find_synth_event(se_name);
6293                 if (se)
6294                         se->ref--;
6295                 ret = 0;
6296                 goto out_free;
6297         }
6298
6299         ret = cmd_ops->reg(glob, trigger_data, file);
6300         /*
6301          * The above returns on success the # of triggers registered,
6302          * but if it didn't register any it returns zero.  Consider no
6303          * triggers registered a failure too.
6304          */
6305         if (!ret) {
6306                 if (!(attrs->pause || attrs->cont || attrs->clear))
6307                         ret = -ENOENT;
6308                 goto out_free;
6309         } else if (ret < 0)
6310                 goto out_free;
6311
6312         if (get_named_trigger_data(trigger_data))
6313                 goto enable;
6314
6315         if (has_hist_vars(hist_data))
6316                 save_hist_vars(hist_data);
6317
6318         ret = create_actions(hist_data);
6319         if (ret)
6320                 goto out_unreg;
6321
6322         ret = tracing_map_init(hist_data->map);
6323         if (ret)
6324                 goto out_unreg;
6325 enable:
6326         ret = hist_trigger_enable(trigger_data, file);
6327         if (ret)
6328                 goto out_unreg;
6329
6330         se_name = trace_event_name(file->event_call);
6331         se = find_synth_event(se_name);
6332         if (se)
6333                 se->ref++;
6334         /* Just return zero, not the number of registered triggers */
6335         ret = 0;
6336  out:
6337         if (ret == 0)
6338                 hist_err_clear();
6339
6340         return ret;
6341  out_unreg:
6342         cmd_ops->unreg(glob+1, trigger_data, file);
6343  out_free:
6344         if (cmd_ops->set_filter)
6345                 cmd_ops->set_filter(NULL, trigger_data, NULL);
6346
6347         remove_hist_vars(hist_data);
6348
6349         kfree(trigger_data);
6350
6351         destroy_hist_data(hist_data);
6352         goto out;
6353 }
6354
6355 static struct event_command trigger_hist_cmd = {
6356         .name                   = "hist",
6357         .trigger_type           = ETT_EVENT_HIST,
6358         .flags                  = EVENT_CMD_FL_NEEDS_REC,
6359         .parse                  = event_hist_trigger_parse,
6360         .reg                    = hist_register_trigger,
6361         .unreg                  = hist_unregister_trigger,
6362         .unreg_all              = hist_unreg_all,
6363         .get_trigger_ops        = event_hist_get_trigger_ops,
6364         .set_filter             = set_trigger_filter,
6365 };
6366
6367 __init int register_trigger_hist_cmd(void)
6368 {
6369         int ret;
6370
6371         ret = register_event_command(&trigger_hist_cmd);
6372         WARN_ON(ret < 0);
6373
6374         return ret;
6375 }
6376
6377 static void
6378 hist_enable_trigger(struct event_trigger_data *data,
6379                     struct trace_buffer *buffer,  void *rec,
6380                     struct ring_buffer_event *event)
6381 {
6382         struct enable_trigger_data *enable_data = data->private_data;
6383         struct event_trigger_data *test;
6384
6385         list_for_each_entry_rcu(test, &enable_data->file->triggers, list,
6386                                 lockdep_is_held(&event_mutex)) {
6387                 if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6388                         if (enable_data->enable)
6389                                 test->paused = false;
6390                         else
6391                                 test->paused = true;
6392                 }
6393         }
6394 }
6395
6396 static void
6397 hist_enable_count_trigger(struct event_trigger_data *data,
6398                           struct trace_buffer *buffer,  void *rec,
6399                           struct ring_buffer_event *event)
6400 {
6401         if (!data->count)
6402                 return;
6403
6404         if (data->count != -1)
6405                 (data->count)--;
6406
6407         hist_enable_trigger(data, buffer, rec, event);
6408 }
6409
6410 static struct event_trigger_ops hist_enable_trigger_ops = {
6411         .trigger                = hist_enable_trigger,
6412         .print                  = event_enable_trigger_print,
6413         .init                   = event_trigger_init,
6414         .free                   = event_enable_trigger_free,
6415 };
6416
6417 static struct event_trigger_ops hist_enable_count_trigger_ops = {
6418         .trigger                = hist_enable_count_trigger,
6419         .print                  = event_enable_trigger_print,
6420         .init                   = event_trigger_init,
6421         .free                   = event_enable_trigger_free,
6422 };
6423
6424 static struct event_trigger_ops hist_disable_trigger_ops = {
6425         .trigger                = hist_enable_trigger,
6426         .print                  = event_enable_trigger_print,
6427         .init                   = event_trigger_init,
6428         .free                   = event_enable_trigger_free,
6429 };
6430
6431 static struct event_trigger_ops hist_disable_count_trigger_ops = {
6432         .trigger                = hist_enable_count_trigger,
6433         .print                  = event_enable_trigger_print,
6434         .init                   = event_trigger_init,
6435         .free                   = event_enable_trigger_free,
6436 };
6437
6438 static struct event_trigger_ops *
6439 hist_enable_get_trigger_ops(char *cmd, char *param)
6440 {
6441         struct event_trigger_ops *ops;
6442         bool enable;
6443
6444         enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
6445
6446         if (enable)
6447                 ops = param ? &hist_enable_count_trigger_ops :
6448                         &hist_enable_trigger_ops;
6449         else
6450                 ops = param ? &hist_disable_count_trigger_ops :
6451                         &hist_disable_trigger_ops;
6452
6453         return ops;
6454 }
6455
6456 static void hist_enable_unreg_all(struct trace_event_file *file)
6457 {
6458         struct event_trigger_data *test, *n;
6459
6460         list_for_each_entry_safe(test, n, &file->triggers, list) {
6461                 if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
6462                         list_del_rcu(&test->list);
6463                         update_cond_flag(file);
6464                         trace_event_trigger_enable_disable(file, 0);
6465                         if (test->ops->free)
6466                                 test->ops->free(test->ops, test);
6467                 }
6468         }
6469 }
6470
6471 static struct event_command trigger_hist_enable_cmd = {
6472         .name                   = ENABLE_HIST_STR,
6473         .trigger_type           = ETT_HIST_ENABLE,
6474         .parse                  = event_enable_trigger_parse,
6475         .reg                    = event_enable_register_trigger,
6476         .unreg                  = event_enable_unregister_trigger,
6477         .unreg_all              = hist_enable_unreg_all,
6478         .get_trigger_ops        = hist_enable_get_trigger_ops,
6479         .set_filter             = set_trigger_filter,
6480 };
6481
6482 static struct event_command trigger_hist_disable_cmd = {
6483         .name                   = DISABLE_HIST_STR,
6484         .trigger_type           = ETT_HIST_ENABLE,
6485         .parse                  = event_enable_trigger_parse,
6486         .reg                    = event_enable_register_trigger,
6487         .unreg                  = event_enable_unregister_trigger,
6488         .unreg_all              = hist_enable_unreg_all,
6489         .get_trigger_ops        = hist_enable_get_trigger_ops,
6490         .set_filter             = set_trigger_filter,
6491 };
6492
6493 static __init void unregister_trigger_hist_enable_disable_cmds(void)
6494 {
6495         unregister_event_command(&trigger_hist_enable_cmd);
6496         unregister_event_command(&trigger_hist_disable_cmd);
6497 }
6498
6499 __init int register_trigger_hist_enable_disable_cmds(void)
6500 {
6501         int ret;
6502
6503         ret = register_event_command(&trigger_hist_enable_cmd);
6504         if (WARN_ON(ret < 0))
6505                 return ret;
6506         ret = register_event_command(&trigger_hist_disable_cmd);
6507         if (WARN_ON(ret < 0))
6508                 unregister_trigger_hist_enable_disable_cmds();
6509
6510         return ret;
6511 }