kernel/trace/trace_events_hist.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * trace_events_hist - trace event hist triggers
0004  *
0005  * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
0006  */
0007
0008 #include <linux/module.h>
0009 #include <linux/kallsyms.h>
0010 #include <linux/security.h>
0011 #include <linux/mutex.h>
0012 #include <linux/slab.h>
0013 #include <linux/stacktrace.h>
0014 #include <linux/rculist.h>
0015 #include <linux/tracefs.h>
0016
0017 /* for gfp flag names */
0018 #include <linux/trace_events.h>
0019 #include <trace/events/mmflags.h>
0020
0021 #include "tracing_map.h"
0022 #include "trace_synth.h"
0023
0024 #define ERRORS                              \
0025     C(NONE,         "No error"),                \
0026     C(DUPLICATE_VAR,    "Variable already defined"),        \
0027     C(VAR_NOT_UNIQUE,   "Variable name not unique, need to use fully qualified name (subsys.event.var) for variable"), \
0028     C(TOO_MANY_VARS,    "Too many variables defined"),      \
0029     C(MALFORMED_ASSIGNMENT, "Malformed assignment"),        \
0030     C(NAMED_MISMATCH,   "Named hist trigger doesn't match existing named trigger (includes variables)"), \
0031     C(TRIGGER_EEXIST,   "Hist trigger already exists"),     \
0032     C(TRIGGER_ENOENT_CLEAR, "Can't clear or continue a nonexistent hist trigger"), \
0033     C(SET_CLOCK_FAIL,   "Couldn't set trace_clock"),        \
0034     C(BAD_FIELD_MODIFIER,   "Invalid field modifier"),      \
0035     C(TOO_MANY_SUBEXPR, "Too many subexpressions (3 max)"), \
0036     C(TIMESTAMP_MISMATCH,   "Timestamp units in expression don't match"), \
0037     C(TOO_MANY_FIELD_VARS,  "Too many field variables defined"),    \
0038     C(EVENT_FILE_NOT_FOUND, "Event file not found"),        \
0039     C(HIST_NOT_FOUND,   "Matching event histogram not found"),  \
0040     C(HIST_CREATE_FAIL, "Couldn't create histogram for field"), \
0041     C(SYNTH_VAR_NOT_FOUND,  "Couldn't find synthetic variable"),    \
0042     C(SYNTH_EVENT_NOT_FOUND,"Couldn't find synthetic event"),   \
0043     C(SYNTH_TYPE_MISMATCH,  "Param type doesn't match synthetic event field type"), \
0044     C(SYNTH_COUNT_MISMATCH, "Param count doesn't match synthetic event field count"), \
0045     C(FIELD_VAR_PARSE_FAIL, "Couldn't parse field variable"),   \
0046     C(VAR_CREATE_FIND_FAIL, "Couldn't create or find variable"),    \
0047     C(ONX_NOT_VAR,      "For onmax(x) or onchange(x), x must be a variable"), \
0048     C(ONX_VAR_NOT_FOUND,    "Couldn't find onmax or onchange variable"), \
0049     C(ONX_VAR_CREATE_FAIL,  "Couldn't create onmax or onchange variable"), \
0050     C(FIELD_VAR_CREATE_FAIL,"Couldn't create field variable"),  \
0051     C(TOO_MANY_PARAMS,  "Too many action params"),      \
0052     C(PARAM_NOT_FOUND,  "Couldn't find param"),         \
0053     C(INVALID_PARAM,    "Invalid action param"),        \
0054     C(ACTION_NOT_FOUND, "No action found"),         \
0055     C(NO_SAVE_PARAMS,   "No params found for save()"),      \
0056     C(TOO_MANY_SAVE_ACTIONS,"Can't have more than one save() action per hist"), \
0057     C(ACTION_MISMATCH,  "Handler doesn't support action"),  \
0058     C(NO_CLOSING_PAREN, "No closing paren found"),      \
0059     C(SUBSYS_NOT_FOUND, "Missing subsystem"),           \
0060     C(INVALID_SUBSYS_EVENT, "Invalid subsystem or event name"), \
0061     C(INVALID_REF_KEY,  "Using variable references in keys not supported"), \
0062     C(VAR_NOT_FOUND,    "Couldn't find variable"),      \
0063     C(FIELD_NOT_FOUND,  "Couldn't find field"),         \
0064     C(EMPTY_ASSIGNMENT, "Empty assignment"),            \
0065     C(INVALID_SORT_MODIFIER,"Invalid sort modifier"),       \
0066     C(EMPTY_SORT_FIELD, "Empty sort field"),            \
0067     C(TOO_MANY_SORT_FIELDS, "Too many sort fields (Max = 2)"),  \
0068     C(INVALID_SORT_FIELD,   "Sort field must be a key or a val"),   \
0069     C(INVALID_STR_OPERAND,  "String type can not be an operand in expression"), \
0070     C(EXPECT_NUMBER,    "Expecting numeric literal"),       \
0071     C(UNARY_MINUS_SUBEXPR,  "Unary minus not supported in sub-expressions"), \
0072     C(DIVISION_BY_ZERO, "Division by zero"),
0073
0074 #undef C
0075 #define C(a, b)     HIST_ERR_##a
0076
0077 enum { ERRORS };
0078
0079 #undef C
0080 #define C(a, b)     b
0081
0082 static const char *err_text[] = { ERRORS };
0083
0084 struct hist_field;
0085
0086 typedef u64 (*hist_field_fn_t) (struct hist_field *field,
0087                 struct tracing_map_elt *elt,
0088                 struct trace_buffer *buffer,
0089                 struct ring_buffer_event *rbe,
0090                 void *event);
0091
0092 #define HIST_FIELD_OPERANDS_MAX 2
0093 #define HIST_FIELDS_MAX     (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
0094 #define HIST_ACTIONS_MAX    8
0095 #define HIST_CONST_DIGITS_MAX   21
0096 #define HIST_DIV_SHIFT      20  /* For optimizing division by constants */
0097
0098 enum field_op_id {
0099     FIELD_OP_NONE,
0100     FIELD_OP_PLUS,
0101     FIELD_OP_MINUS,
0102     FIELD_OP_UNARY_MINUS,
0103     FIELD_OP_DIV,
0104     FIELD_OP_MULT,
0105 };
0106
0107 /*
0108  * A hist_var (histogram variable) contains variable information for
0109  * hist_fields having the HIST_FIELD_FL_VAR or HIST_FIELD_FL_VAR_REF
0110  * flag set.  A hist_var has a variable name e.g. ts0, and is
0111  * associated with a given histogram trigger, as specified by
0112  * hist_data.  The hist_var idx is the unique index assigned to the
0113  * variable by the hist trigger's tracing_map.  The idx is what is
0114  * used to set a variable's value and, by a variable reference, to
0115  * retrieve it.
0116  */
0117 struct hist_var {
0118     char                *name;
0119     struct hist_trigger_data    *hist_data;
0120     unsigned int            idx;
0121 };
0122
0123 struct hist_field {
0124     struct ftrace_event_field   *field;
0125     unsigned long           flags;
0126     hist_field_fn_t         fn;
0127     unsigned int            ref;
0128     unsigned int            size;
0129     unsigned int            offset;
0130     unsigned int                    is_signed;
0131     unsigned long           buckets;
0132     const char          *type;
0133     struct hist_field       *operands[HIST_FIELD_OPERANDS_MAX];
0134     struct hist_trigger_data    *hist_data;
0135
0136     /*
0137      * Variable fields contain variable-specific info in var.
0138      */
0139     struct hist_var         var;
0140     enum field_op_id        operator;
0141     char                *system;
0142     char                *event_name;
0143
0144     /*
0145      * The name field is used for EXPR and VAR_REF fields.  VAR
0146      * fields contain the variable name in var.name.
0147      */
0148     char                *name;
0149
0150     /*
0151      * When a histogram trigger is hit, if it has any references
0152      * to variables, the values of those variables are collected
0153      * into a var_ref_vals array by resolve_var_refs().  The
0154      * current value of each variable is read from the tracing_map
0155      * using the hist field's hist_var.idx and entered into the
0156      * var_ref_idx entry i.e. var_ref_vals[var_ref_idx].
0157      */
0158     unsigned int            var_ref_idx;
0159     bool                            read_once;
0160
0161     unsigned int            var_str_idx;
0162
0163     /* Numeric literals are represented as u64 */
0164     u64             constant;
0165     /* Used to optimize division by constants */
0166     u64             div_multiplier;
0167 };
0168
0169 static u64 hist_field_none(struct hist_field *field,
0170                struct tracing_map_elt *elt,
0171                struct trace_buffer *buffer,
0172                struct ring_buffer_event *rbe,
0173                void *event)
0174 {
0175     return 0;
0176 }
0177
0178 static u64 hist_field_const(struct hist_field *field,
0179                struct tracing_map_elt *elt,
0180                struct trace_buffer *buffer,
0181                struct ring_buffer_event *rbe,
0182                void *event)
0183 {
0184     return field->constant;
0185 }
0186
0187 static u64 hist_field_counter(struct hist_field *field,
0188                   struct tracing_map_elt *elt,
0189                   struct trace_buffer *buffer,
0190                   struct ring_buffer_event *rbe,
0191                   void *event)
0192 {
0193     return 1;
0194 }
0195
0196 static u64 hist_field_string(struct hist_field *hist_field,
0197                  struct tracing_map_elt *elt,
0198                  struct trace_buffer *buffer,
0199                  struct ring_buffer_event *rbe,
0200                  void *event)
0201 {
0202     char *addr = (char *)(event + hist_field->field->offset);
0203
0204     return (u64)(unsigned long)addr;
0205 }
0206
0207 static u64 hist_field_dynstring(struct hist_field *hist_field,
0208                 struct tracing_map_elt *elt,
0209                 struct trace_buffer *buffer,
0210                 struct ring_buffer_event *rbe,
0211                 void *event)
0212 {
0213     u32 str_item = *(u32 *)(event + hist_field->field->offset);
0214     int str_loc = str_item & 0xffff;
0215     char *addr = (char *)(event + str_loc);
0216
0217     return (u64)(unsigned long)addr;
0218 }
0219
0220 static u64 hist_field_reldynstring(struct hist_field *hist_field,
0221                    struct tracing_map_elt *elt,
0222                    struct trace_buffer *buffer,
0223                    struct ring_buffer_event *rbe,
0224                    void *event)
0225 {
0226     u32 *item = event + hist_field->field->offset;
0227     u32 str_item = *item;
0228     int str_loc = str_item & 0xffff;
0229     char *addr = (char *)&item[1] + str_loc;
0230
0231     return (u64)(unsigned long)addr;
0232 }
0233
0234 static u64 hist_field_pstring(struct hist_field *hist_field,
0235                   struct tracing_map_elt *elt,
0236                   struct trace_buffer *buffer,
0237                   struct ring_buffer_event *rbe,
0238                   void *event)
0239 {
0240     char **addr = (char **)(event + hist_field->field->offset);
0241
0242     return (u64)(unsigned long)*addr;
0243 }
0244
0245 static u64 hist_field_log2(struct hist_field *hist_field,
0246                struct tracing_map_elt *elt,
0247                struct trace_buffer *buffer,
0248                struct ring_buffer_event *rbe,
0249                void *event)
0250 {
0251     struct hist_field *operand = hist_field->operands[0];
0252
0253     u64 val = operand->fn(operand, elt, buffer, rbe, event);
0254
0255     return (u64) ilog2(roundup_pow_of_two(val));
0256 }
0257
0258 static u64 hist_field_bucket(struct hist_field *hist_field,
0259                  struct tracing_map_elt *elt,
0260                  struct trace_buffer *buffer,
0261                  struct ring_buffer_event *rbe,
0262                  void *event)
0263 {
0264     struct hist_field *operand = hist_field->operands[0];
0265     unsigned long buckets = hist_field->buckets;
0266
0267     u64 val = operand->fn(operand, elt, buffer, rbe, event);
0268
0269     if (WARN_ON_ONCE(!buckets))
0270         return val;
0271
0272     if (val >= LONG_MAX)
0273         val = div64_ul(val, buckets);
0274     else
0275         val = (u64)((unsigned long)val / buckets);
0276     return val * buckets;
0277 }
0278
0279 static u64 hist_field_plus(struct hist_field *hist_field,
0280                struct tracing_map_elt *elt,
0281                struct trace_buffer *buffer,
0282                struct ring_buffer_event *rbe,
0283                void *event)
0284 {
0285     struct hist_field *operand1 = hist_field->operands[0];
0286     struct hist_field *operand2 = hist_field->operands[1];
0287
0288     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0289     u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
0290
0291     return val1 + val2;
0292 }
0293
0294 static u64 hist_field_minus(struct hist_field *hist_field,
0295                 struct tracing_map_elt *elt,
0296                 struct trace_buffer *buffer,
0297                 struct ring_buffer_event *rbe,
0298                 void *event)
0299 {
0300     struct hist_field *operand1 = hist_field->operands[0];
0301     struct hist_field *operand2 = hist_field->operands[1];
0302
0303     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0304     u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
0305
0306     return val1 - val2;
0307 }
0308
0309 static u64 hist_field_div(struct hist_field *hist_field,
0310                struct tracing_map_elt *elt,
0311                struct trace_buffer *buffer,
0312                struct ring_buffer_event *rbe,
0313                void *event)
0314 {
0315     struct hist_field *operand1 = hist_field->operands[0];
0316     struct hist_field *operand2 = hist_field->operands[1];
0317
0318     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0319     u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
0320
0321     /* Return -1 for the undefined case */
0322     if (!val2)
0323         return -1;
0324
0325     /* Use shift if the divisor is a power of 2 */
0326     if (!(val2 & (val2 - 1)))
0327         return val1 >> __ffs64(val2);
0328
0329     return div64_u64(val1, val2);
0330 }
0331
0332 static u64 div_by_power_of_two(struct hist_field *hist_field,
0333                 struct tracing_map_elt *elt,
0334                 struct trace_buffer *buffer,
0335                 struct ring_buffer_event *rbe,
0336                 void *event)
0337 {
0338     struct hist_field *operand1 = hist_field->operands[0];
0339     struct hist_field *operand2 = hist_field->operands[1];
0340
0341     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0342
0343     return val1 >> __ffs64(operand2->constant);
0344 }
0345
0346 static u64 div_by_not_power_of_two(struct hist_field *hist_field,
0347                 struct tracing_map_elt *elt,
0348                 struct trace_buffer *buffer,
0349                 struct ring_buffer_event *rbe,
0350                 void *event)
0351 {
0352     struct hist_field *operand1 = hist_field->operands[0];
0353     struct hist_field *operand2 = hist_field->operands[1];
0354
0355     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0356
0357     return div64_u64(val1, operand2->constant);
0358 }
0359
0360 static u64 div_by_mult_and_shift(struct hist_field *hist_field,
0361                 struct tracing_map_elt *elt,
0362                 struct trace_buffer *buffer,
0363                 struct ring_buffer_event *rbe,
0364                 void *event)
0365 {
0366     struct hist_field *operand1 = hist_field->operands[0];
0367     struct hist_field *operand2 = hist_field->operands[1];
0368
0369     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0370
0371     /*
0372      * If the divisor is a constant, do a multiplication and shift instead.
0373      *
0374      * Choose Z = some power of 2. If Y <= Z, then:
0375      *     X / Y = (X * (Z / Y)) / Z
0376      *
0377      * (Z / Y) is a constant (mult) which is calculated at parse time, so:
0378      *     X / Y = (X * mult) / Z
0379      *
0380      * The division by Z can be replaced by a shift since Z is a power of 2:
0381      *     X / Y = (X * mult) >> HIST_DIV_SHIFT
0382      *
0383      * As long, as X < Z the results will not be off by more than 1.
0384      */
0385     if (val1 < (1 << HIST_DIV_SHIFT)) {
0386         u64 mult = operand2->div_multiplier;
0387
0388         return (val1 * mult + ((1 << HIST_DIV_SHIFT) - 1)) >> HIST_DIV_SHIFT;
0389     }
0390
0391     return div64_u64(val1, operand2->constant);
0392 }
0393
0394 static u64 hist_field_mult(struct hist_field *hist_field,
0395                struct tracing_map_elt *elt,
0396                struct trace_buffer *buffer,
0397                struct ring_buffer_event *rbe,
0398                void *event)
0399 {
0400     struct hist_field *operand1 = hist_field->operands[0];
0401     struct hist_field *operand2 = hist_field->operands[1];
0402
0403     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
0404     u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
0405
0406     return val1 * val2;
0407 }
0408
0409 static u64 hist_field_unary_minus(struct hist_field *hist_field,
0410                   struct tracing_map_elt *elt,
0411                   struct trace_buffer *buffer,
0412                   struct ring_buffer_event *rbe,
0413                   void *event)
0414 {
0415     struct hist_field *operand = hist_field->operands[0];
0416
0417     s64 sval = (s64)operand->fn(operand, elt, buffer, rbe, event);
0418     u64 val = (u64)-sval;
0419
0420     return val;
0421 }
0422
0423 #define DEFINE_HIST_FIELD_FN(type)                  \
0424     static u64 hist_field_##type(struct hist_field *hist_field, \
0425                      struct tracing_map_elt *elt,   \
0426                      struct trace_buffer *buffer,   \
0427                      struct ring_buffer_event *rbe, \
0428                      void *event)           \
0429 {                                   \
0430     type *addr = (type *)(event + hist_field->field->offset);   \
0431                                     \
0432     return (u64)(unsigned long)*addr;               \
0433 }
0434
0435 DEFINE_HIST_FIELD_FN(s64);
0436 DEFINE_HIST_FIELD_FN(u64);
0437 DEFINE_HIST_FIELD_FN(s32);
0438 DEFINE_HIST_FIELD_FN(u32);
0439 DEFINE_HIST_FIELD_FN(s16);
0440 DEFINE_HIST_FIELD_FN(u16);
0441 DEFINE_HIST_FIELD_FN(s8);
0442 DEFINE_HIST_FIELD_FN(u8);
0443
0444 #define for_each_hist_field(i, hist_data)   \
0445     for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
0446
0447 #define for_each_hist_val_field(i, hist_data)   \
0448     for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
0449
0450 #define for_each_hist_key_field(i, hist_data)   \
0451     for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
0452
0453 #define HIST_STACKTRACE_DEPTH   16
0454 #define HIST_STACKTRACE_SIZE    (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
0455 #define HIST_STACKTRACE_SKIP    5
0456
0457 #define HITCOUNT_IDX        0
0458 #define HIST_KEY_SIZE_MAX   (MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
0459
0460 enum hist_field_flags {
0461     HIST_FIELD_FL_HITCOUNT      = 1 << 0,
0462     HIST_FIELD_FL_KEY       = 1 << 1,
0463     HIST_FIELD_FL_STRING        = 1 << 2,
0464     HIST_FIELD_FL_HEX       = 1 << 3,
0465     HIST_FIELD_FL_SYM       = 1 << 4,
0466     HIST_FIELD_FL_SYM_OFFSET    = 1 << 5,
0467     HIST_FIELD_FL_EXECNAME      = 1 << 6,
0468     HIST_FIELD_FL_SYSCALL       = 1 << 7,
0469     HIST_FIELD_FL_STACKTRACE    = 1 << 8,
0470     HIST_FIELD_FL_LOG2      = 1 << 9,
0471     HIST_FIELD_FL_TIMESTAMP     = 1 << 10,
0472     HIST_FIELD_FL_TIMESTAMP_USECS   = 1 << 11,
0473     HIST_FIELD_FL_VAR       = 1 << 12,
0474     HIST_FIELD_FL_EXPR      = 1 << 13,
0475     HIST_FIELD_FL_VAR_REF       = 1 << 14,
0476     HIST_FIELD_FL_CPU       = 1 << 15,
0477     HIST_FIELD_FL_ALIAS     = 1 << 16,
0478     HIST_FIELD_FL_BUCKET        = 1 << 17,
0479     HIST_FIELD_FL_CONST     = 1 << 18,
0480 };
0481
0482 struct var_defs {
0483     unsigned int    n_vars;
0484     char        *name[TRACING_MAP_VARS_MAX];
0485     char        *expr[TRACING_MAP_VARS_MAX];
0486 };
0487
0488 struct hist_trigger_attrs {
0489     char        *keys_str;
0490     char        *vals_str;
0491     char        *sort_key_str;
0492     char        *name;
0493     char        *clock;
0494     bool        pause;
0495     bool        cont;
0496     bool        clear;
0497     bool        ts_in_usecs;
0498     unsigned int    map_bits;
0499
0500     char        *assignment_str[TRACING_MAP_VARS_MAX];
0501     unsigned int    n_assignments;
0502
0503     char        *action_str[HIST_ACTIONS_MAX];
0504     unsigned int    n_actions;
0505
0506     struct var_defs var_defs;
0507 };
0508
0509 struct field_var {
0510     struct hist_field   *var;
0511     struct hist_field   *val;
0512 };
0513
0514 struct field_var_hist {
0515     struct hist_trigger_data    *hist_data;
0516     char                *cmd;
0517 };
0518
0519 struct hist_trigger_data {
0520     struct hist_field               *fields[HIST_FIELDS_MAX];
0521     unsigned int            n_vals;
0522     unsigned int            n_keys;
0523     unsigned int            n_fields;
0524     unsigned int            n_vars;
0525     unsigned int            n_var_str;
0526     unsigned int            key_size;
0527     struct tracing_map_sort_key sort_keys[TRACING_MAP_SORT_KEYS_MAX];
0528     unsigned int            n_sort_keys;
0529     struct trace_event_file     *event_file;
0530     struct hist_trigger_attrs   *attrs;
0531     struct tracing_map      *map;
0532     bool                enable_timestamps;
0533     bool                remove;
0534     struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
0535     unsigned int            n_var_refs;
0536
0537     struct action_data      *actions[HIST_ACTIONS_MAX];
0538     unsigned int            n_actions;
0539
0540     struct field_var        *field_vars[SYNTH_FIELDS_MAX];
0541     unsigned int            n_field_vars;
0542     unsigned int            n_field_var_str;
0543     struct field_var_hist       *field_var_hists[SYNTH_FIELDS_MAX];
0544     unsigned int            n_field_var_hists;
0545
0546     struct field_var        *save_vars[SYNTH_FIELDS_MAX];
0547     unsigned int            n_save_vars;
0548     unsigned int            n_save_var_str;
0549 };
0550
0551 struct action_data;
0552
0553 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
0554                  struct tracing_map_elt *elt,
0555                  struct trace_buffer *buffer, void *rec,
0556                  struct ring_buffer_event *rbe, void *key,
0557                  struct action_data *data, u64 *var_ref_vals);
0558
0559 typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
0560
0561 enum handler_id {
0562     HANDLER_ONMATCH = 1,
0563     HANDLER_ONMAX,
0564     HANDLER_ONCHANGE,
0565 };
0566
0567 enum action_id {
0568     ACTION_SAVE = 1,
0569     ACTION_TRACE,
0570     ACTION_SNAPSHOT,
0571 };
0572
0573 struct action_data {
0574     enum handler_id     handler;
0575     enum action_id      action;
0576     char            *action_name;
0577     action_fn_t     fn;
0578
0579     unsigned int        n_params;
0580     char            *params[SYNTH_FIELDS_MAX];
0581
0582     /*
0583      * When a histogram trigger is hit, the values of any
0584      * references to variables, including variables being passed
0585      * as parameters to synthetic events, are collected into a
0586      * var_ref_vals array.  This var_ref_idx array is an array of
0587      * indices into the var_ref_vals array, one for each synthetic
0588      * event param, and is passed to the synthetic event
0589      * invocation.
0590      */
0591     unsigned int        var_ref_idx[TRACING_MAP_VARS_MAX];
0592     struct synth_event  *synth_event;
0593     bool            use_trace_keyword;
0594     char            *synth_event_name;
0595
0596     union {
0597         struct {
0598             char            *event;
0599             char            *event_system;
0600         } match_data;
0601
0602         struct {
0603             /*
0604              * var_str contains the $-unstripped variable
0605              * name referenced by var_ref, and used when
0606              * printing the action.  Because var_ref
0607              * creation is deferred to create_actions(),
0608              * we need a per-action way to save it until
0609              * then, thus var_str.
0610              */
0611             char            *var_str;
0612
0613             /*
0614              * var_ref refers to the variable being
0615              * tracked e.g onmax($var).
0616              */
0617             struct hist_field   *var_ref;
0618
0619             /*
0620              * track_var contains the 'invisible' tracking
0621              * variable created to keep the current
0622              * e.g. max value.
0623              */
0624             struct hist_field   *track_var;
0625
0626             check_track_val_fn_t    check_val;
0627             action_fn_t     save_data;
0628         } track_data;
0629     };
0630 };
0631
0632 struct track_data {
0633     u64             track_val;
0634     bool                updated;
0635
0636     unsigned int            key_len;
0637     void                *key;
0638     struct tracing_map_elt      elt;
0639
0640     struct action_data      *action_data;
0641     struct hist_trigger_data    *hist_data;
0642 };
0643
0644 struct hist_elt_data {
0645     char *comm;
0646     u64 *var_ref_vals;
0647     char **field_var_str;
0648     int n_field_var_str;
0649 };
0650
0651 struct snapshot_context {
0652     struct tracing_map_elt  *elt;
0653     void            *key;
0654 };
0655
0656 /*
0657  * Returns the specific division function to use if the divisor
0658  * is constant. This avoids extra branches when the trigger is hit.
0659  */
0660 static hist_field_fn_t hist_field_get_div_fn(struct hist_field *divisor)
0661 {
0662     u64 div = divisor->constant;
0663
0664     if (!(div & (div - 1)))
0665         return div_by_power_of_two;
0666
0667     /* If the divisor is too large, do a regular division */
0668     if (div > (1 << HIST_DIV_SHIFT))
0669         return div_by_not_power_of_two;
0670
0671     divisor->div_multiplier = div64_u64((u64)(1 << HIST_DIV_SHIFT), div);
0672     return div_by_mult_and_shift;
0673 }
0674
0675 static void track_data_free(struct track_data *track_data)
0676 {
0677     struct hist_elt_data *elt_data;
0678
0679     if (!track_data)
0680         return;
0681
0682     kfree(track_data->key);
0683
0684     elt_data = track_data->elt.private_data;
0685     if (elt_data) {
0686         kfree(elt_data->comm);
0687         kfree(elt_data);
0688     }
0689
0690     kfree(track_data);
0691 }
0692
0693 static struct track_data *track_data_alloc(unsigned int key_len,
0694                        struct action_data *action_data,
0695                        struct hist_trigger_data *hist_data)
0696 {
0697     struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
0698     struct hist_elt_data *elt_data;
0699
0700     if (!data)
0701         return ERR_PTR(-ENOMEM);
0702
0703     data->key = kzalloc(key_len, GFP_KERNEL);
0704     if (!data->key) {
0705         track_data_free(data);
0706         return ERR_PTR(-ENOMEM);
0707     }
0708
0709     data->key_len = key_len;
0710     data->action_data = action_data;
0711     data->hist_data = hist_data;
0712
0713     elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
0714     if (!elt_data) {
0715         track_data_free(data);
0716         return ERR_PTR(-ENOMEM);
0717     }
0718
0719     data->elt.private_data = elt_data;
0720
0721     elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
0722     if (!elt_data->comm) {
0723         track_data_free(data);
0724         return ERR_PTR(-ENOMEM);
0725     }
0726
0727     return data;
0728 }
0729
0730 #define HIST_PREFIX "hist:"
0731
0732 static char *last_cmd;
0733 static char last_cmd_loc[MAX_FILTER_STR_VAL];
0734
0735 static int errpos(char *str)
0736 {
0737     if (!str || !last_cmd)
0738         return 0;
0739
0740     return err_pos(last_cmd, str);
0741 }
0742
0743 static void last_cmd_set(struct trace_event_file *file, char *str)
0744 {
0745     const char *system = NULL, *name = NULL;
0746     struct trace_event_call *call;
0747     int len;
0748
0749     if (!str)
0750         return;
0751
0752     /* sizeof() contains the nul byte */
0753     len = sizeof(HIST_PREFIX) + strlen(str);
0754     kfree(last_cmd);
0755     last_cmd = kzalloc(len, GFP_KERNEL);
0756     if (!last_cmd)
0757         return;
0758
0759     strcpy(last_cmd, HIST_PREFIX);
0760     /* Again, sizeof() contains the nul byte */
0761     len -= sizeof(HIST_PREFIX);
0762     strncat(last_cmd, str, len);
0763
0764     if (file) {
0765         call = file->event_call;
0766         system = call->class->system;
0767         if (system) {
0768             name = trace_event_name(call);
0769             if (!name)
0770                 system = NULL;
0771         }
0772     }
0773
0774     if (system)
0775         snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name);
0776 }
0777
0778 static void hist_err(struct trace_array *tr, u8 err_type, u16 err_pos)
0779 {
0780     if (!last_cmd)
0781         return;
0782
0783     tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
0784             err_type, err_pos);
0785 }
0786
0787 static void hist_err_clear(void)
0788 {
0789     if (last_cmd)
0790         last_cmd[0] = '\0';
0791     last_cmd_loc[0] = '\0';
0792 }
0793
0794 typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
0795                     unsigned int *var_ref_idx);
0796
0797 static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
0798                    unsigned int *var_ref_idx)
0799 {
0800     struct tracepoint *tp = event->tp;
0801
0802     if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
0803         struct tracepoint_func *probe_func_ptr;
0804         synth_probe_func_t probe_func;
0805         void *__data;
0806
0807         if (!(cpu_online(raw_smp_processor_id())))
0808             return;
0809
0810         probe_func_ptr = rcu_dereference_sched((tp)->funcs);
0811         if (probe_func_ptr) {
0812             do {
0813                 probe_func = probe_func_ptr->func;
0814                 __data = probe_func_ptr->data;
0815                 probe_func(__data, var_ref_vals, var_ref_idx);
0816             } while ((++probe_func_ptr)->func);
0817         }
0818     }
0819 }
0820
0821 static void action_trace(struct hist_trigger_data *hist_data,
0822              struct tracing_map_elt *elt,
0823              struct trace_buffer *buffer, void *rec,
0824              struct ring_buffer_event *rbe, void *key,
0825              struct action_data *data, u64 *var_ref_vals)
0826 {
0827     struct synth_event *event = data->synth_event;
0828
0829     trace_synth(event, var_ref_vals, data->var_ref_idx);
0830 }
0831
0832 struct hist_var_data {
0833     struct list_head list;
0834     struct hist_trigger_data *hist_data;
0835 };
0836
0837 static u64 hist_field_timestamp(struct hist_field *hist_field,
0838                 struct tracing_map_elt *elt,
0839                 struct trace_buffer *buffer,
0840                 struct ring_buffer_event *rbe,
0841                 void *event)
0842 {
0843     struct hist_trigger_data *hist_data = hist_field->hist_data;
0844     struct trace_array *tr = hist_data->event_file->tr;
0845
0846     u64 ts = ring_buffer_event_time_stamp(buffer, rbe);
0847
0848     if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
0849         ts = ns2usecs(ts);
0850
0851     return ts;
0852 }
0853
0854 static u64 hist_field_cpu(struct hist_field *hist_field,
0855               struct tracing_map_elt *elt,
0856               struct trace_buffer *buffer,
0857               struct ring_buffer_event *rbe,
0858               void *event)
0859 {
0860     int cpu = smp_processor_id();
0861
0862     return cpu;
0863 }
0864
0865 /**
0866  * check_field_for_var_ref - Check if a VAR_REF field references a variable
0867  * @hist_field: The VAR_REF field to check
0868  * @var_data: The hist trigger that owns the variable
0869  * @var_idx: The trigger variable identifier
0870  *
0871  * Check the given VAR_REF field to see whether or not it references
0872  * the given variable associated with the given trigger.
0873  *
0874  * Return: The VAR_REF field if it does reference the variable, NULL if not
0875  */
0876 static struct hist_field *
0877 check_field_for_var_ref(struct hist_field *hist_field,
0878             struct hist_trigger_data *var_data,
0879             unsigned int var_idx)
0880 {
0881     WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));
0882
0883     if (hist_field && hist_field->var.idx == var_idx &&
0884         hist_field->var.hist_data == var_data)
0885         return hist_field;
0886
0887     return NULL;
0888 }
0889
0890 /**
0891  * find_var_ref - Check if a trigger has a reference to a trigger variable
0892  * @hist_data: The hist trigger that might have a reference to the variable
0893  * @var_data: The hist trigger that owns the variable
0894  * @var_idx: The trigger variable identifier
0895  *
0896  * Check the list of var_refs[] on the first hist trigger to see
0897  * whether any of them are references to the variable on the second
0898  * trigger.
0899  *
0900  * Return: The VAR_REF field referencing the variable if so, NULL if not
0901  */
0902 static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
0903                        struct hist_trigger_data *var_data,
0904                        unsigned int var_idx)
0905 {
0906     struct hist_field *hist_field;
0907     unsigned int i;
0908
0909     for (i = 0; i < hist_data->n_var_refs; i++) {
0910         hist_field = hist_data->var_refs[i];
0911         if (check_field_for_var_ref(hist_field, var_data, var_idx))
0912             return hist_field;
0913     }
0914
0915     return NULL;
0916 }
0917
0918 /**
0919  * find_any_var_ref - Check if there is a reference to a given trigger variable
0920  * @hist_data: The hist trigger
0921  * @var_idx: The trigger variable identifier
0922  *
0923  * Check to see whether the given variable is currently referenced by
0924  * any other trigger.
0925  *
0926  * The trigger the variable is defined on is explicitly excluded - the
0927  * assumption being that a self-reference doesn't prevent a trigger
0928  * from being removed.
0929  *
0930  * Return: The VAR_REF field referencing the variable if so, NULL if not
0931  */
0932 static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
0933                        unsigned int var_idx)
0934 {
0935     struct trace_array *tr = hist_data->event_file->tr;
0936     struct hist_field *found = NULL;
0937     struct hist_var_data *var_data;
0938
0939     list_for_each_entry(var_data, &tr->hist_vars, list) {
0940         if (var_data->hist_data == hist_data)
0941             continue;
0942         found = find_var_ref(var_data->hist_data, hist_data, var_idx);
0943         if (found)
0944             break;
0945     }
0946
0947     return found;
0948 }
0949
0950 /**
0951  * check_var_refs - Check if there is a reference to any of trigger's variables
0952  * @hist_data: The hist trigger
0953  *
0954  * A trigger can define one or more variables.  If any one of them is
0955  * currently referenced by any other trigger, this function will
0956  * determine that.
0957
0958  * Typically used to determine whether or not a trigger can be removed
0959  * - if there are any references to a trigger's variables, it cannot.
0960  *
0961  * Return: True if there is a reference to any of trigger's variables
0962  */
0963 static bool check_var_refs(struct hist_trigger_data *hist_data)
0964 {
0965     struct hist_field *field;
0966     bool found = false;
0967     int i;
0968
0969     for_each_hist_field(i, hist_data) {
0970         field = hist_data->fields[i];
0971         if (field && field->flags & HIST_FIELD_FL_VAR) {
0972             if (find_any_var_ref(hist_data, field->var.idx)) {
0973                 found = true;
0974                 break;
0975             }
0976         }
0977     }
0978
0979     return found;
0980 }
0981
0982 static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
0983 {
0984     struct trace_array *tr = hist_data->event_file->tr;
0985     struct hist_var_data *var_data, *found = NULL;
0986
0987     list_for_each_entry(var_data, &tr->hist_vars, list) {
0988         if (var_data->hist_data == hist_data) {
0989             found = var_data;
0990             break;
0991         }
0992     }
0993
0994     return found;
0995 }
0996
0997 static bool field_has_hist_vars(struct hist_field *hist_field,
0998                 unsigned int level)
0999 {
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     ref_field->system = NULL;
2097     kfree(ref_field->event_name);
2098     ref_field->event_name = NULL;
2099     kfree(ref_field->name);
2100     ref_field->name = NULL;
2101
2102     goto out;
2103 }
2104
2105 static int find_var_ref_idx(struct hist_trigger_data *hist_data,
2106                 struct hist_field *var_field)
2107 {
2108     struct hist_field *ref_field;
2109     int i;
2110
2111     for (i = 0; i < hist_data->n_var_refs; i++) {
2112         ref_field = hist_data->var_refs[i];
2113         if (ref_field->var.idx == var_field->var.idx &&
2114             ref_field->var.hist_data == var_field->hist_data)
2115             return i;
2116     }
2117
2118     return -ENOENT;
2119 }
2120
2121 /**
2122  * create_var_ref - Create a variable reference and attach it to trigger
2123  * @hist_data: The trigger that will be referencing the variable
2124  * @var_field: The VAR field to create a reference to
2125  * @system: The optional system string
2126  * @event_name: The optional event_name string
2127  *
2128  * Given a variable hist_field, create a VAR_REF hist_field that
2129  * represents a reference to it.
2130  *
2131  * This function also adds the reference to the trigger that
2132  * now references the variable.
2133  *
2134  * Return: The VAR_REF field if successful, NULL if not
2135  */
2136 static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
2137                      struct hist_field *var_field,
2138                      char *system, char *event_name)
2139 {
2140     unsigned long flags = HIST_FIELD_FL_VAR_REF;
2141     struct hist_field *ref_field;
2142     int i;
2143
2144     /* Check if the variable already exists */
2145     for (i = 0; i < hist_data->n_var_refs; i++) {
2146         ref_field = hist_data->var_refs[i];
2147         if (ref_field->var.idx == var_field->var.idx &&
2148             ref_field->var.hist_data == var_field->hist_data) {
2149             get_hist_field(ref_field);
2150             return ref_field;
2151         }
2152     }
2153
2154     ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
2155     if (ref_field) {
2156         if (init_var_ref(ref_field, var_field, system, event_name)) {
2157             destroy_hist_field(ref_field, 0);
2158             return NULL;
2159         }
2160
2161         hist_data->var_refs[hist_data->n_var_refs] = ref_field;
2162         ref_field->var_ref_idx = hist_data->n_var_refs++;
2163     }
2164
2165     return ref_field;
2166 }
2167
2168 static bool is_var_ref(char *var_name)
2169 {
2170     if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
2171         return false;
2172
2173     return true;
2174 }
2175
2176 static char *field_name_from_var(struct hist_trigger_data *hist_data,
2177                  char *var_name)
2178 {
2179     char *name, *field;
2180     unsigned int i;
2181
2182     for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
2183         name = hist_data->attrs->var_defs.name[i];
2184
2185         if (strcmp(var_name, name) == 0) {
2186             field = hist_data->attrs->var_defs.expr[i];
2187             if (contains_operator(field, NULL) || is_var_ref(field))
2188                 continue;
2189             return field;
2190         }
2191     }
2192
2193     return NULL;
2194 }
2195
2196 static char *local_field_var_ref(struct hist_trigger_data *hist_data,
2197                  char *system, char *event_name,
2198                  char *var_name)
2199 {
2200     struct trace_event_call *call;
2201
2202     if (system && event_name) {
2203         call = hist_data->event_file->event_call;
2204
2205         if (strcmp(system, call->class->system) != 0)
2206             return NULL;
2207
2208         if (strcmp(event_name, trace_event_name(call)) != 0)
2209             return NULL;
2210     }
2211
2212     if (!!system != !!event_name)
2213         return NULL;
2214
2215     if (!is_var_ref(var_name))
2216         return NULL;
2217
2218     var_name++;
2219
2220     return field_name_from_var(hist_data, var_name);
2221 }
2222
2223 static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
2224                     char *system, char *event_name,
2225                     char *var_name)
2226 {
2227     struct hist_field *var_field = NULL, *ref_field = NULL;
2228     struct trace_array *tr = hist_data->event_file->tr;
2229
2230     if (!is_var_ref(var_name))
2231         return NULL;
2232
2233     var_name++;
2234
2235     var_field = find_event_var(hist_data, system, event_name, var_name);
2236     if (var_field)
2237         ref_field = create_var_ref(hist_data, var_field,
2238                        system, event_name);
2239
2240     if (!ref_field)
2241         hist_err(tr, HIST_ERR_VAR_NOT_FOUND, errpos(var_name));
2242
2243     return ref_field;
2244 }
2245
2246 static struct ftrace_event_field *
2247 parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
2248         char *field_str, unsigned long *flags, unsigned long *buckets)
2249 {
2250     struct ftrace_event_field *field = NULL;
2251     char *field_name, *modifier, *str;
2252     struct trace_array *tr = file->tr;
2253
2254     modifier = str = kstrdup(field_str, GFP_KERNEL);
2255     if (!modifier)
2256         return ERR_PTR(-ENOMEM);
2257
2258     field_name = strsep(&modifier, ".");
2259     if (modifier) {
2260         if (strcmp(modifier, "hex") == 0)
2261             *flags |= HIST_FIELD_FL_HEX;
2262         else if (strcmp(modifier, "sym") == 0)
2263             *flags |= HIST_FIELD_FL_SYM;
2264         /*
2265          * 'sym-offset' occurrences in the trigger string are modified
2266          * to 'symXoffset' to simplify arithmetic expression parsing.
2267          */
2268         else if (strcmp(modifier, "symXoffset") == 0)
2269             *flags |= HIST_FIELD_FL_SYM_OFFSET;
2270         else if ((strcmp(modifier, "execname") == 0) &&
2271              (strcmp(field_name, "common_pid") == 0))
2272             *flags |= HIST_FIELD_FL_EXECNAME;
2273         else if (strcmp(modifier, "syscall") == 0)
2274             *flags |= HIST_FIELD_FL_SYSCALL;
2275         else if (strcmp(modifier, "log2") == 0)
2276             *flags |= HIST_FIELD_FL_LOG2;
2277         else if (strcmp(modifier, "usecs") == 0)
2278             *flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
2279         else if (strncmp(modifier, "bucket", 6) == 0) {
2280             int ret;
2281
2282             modifier += 6;
2283
2284             if (*modifier == 's')
2285                 modifier++;
2286             if (*modifier != '=')
2287                 goto error;
2288             modifier++;
2289             ret = kstrtoul(modifier, 0, buckets);
2290             if (ret || !(*buckets))
2291                 goto error;
2292             *flags |= HIST_FIELD_FL_BUCKET;
2293         } else {
2294  error:
2295             hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
2296             field = ERR_PTR(-EINVAL);
2297             goto out;
2298         }
2299     }
2300
2301     if (strcmp(field_name, "common_timestamp") == 0) {
2302         *flags |= HIST_FIELD_FL_TIMESTAMP;
2303         hist_data->enable_timestamps = true;
2304         if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2305             hist_data->attrs->ts_in_usecs = true;
2306     } else if (strcmp(field_name, "common_cpu") == 0)
2307         *flags |= HIST_FIELD_FL_CPU;
2308     else {
2309         field = trace_find_event_field(file->event_call, field_name);
2310         if (!field || !field->size) {
2311             /*
2312              * For backward compatibility, if field_name
2313              * was "cpu", then we treat this the same as
2314              * common_cpu. This also works for "CPU".
2315              */
2316             if (field && field->filter_type == FILTER_CPU) {
2317                 *flags |= HIST_FIELD_FL_CPU;
2318             } else {
2319                 hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,
2320                      errpos(field_name));
2321                 field = ERR_PTR(-EINVAL);
2322                 goto out;
2323             }
2324         }
2325     }
2326  out:
2327     kfree(str);
2328
2329     return field;
2330 }
2331
2332 static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
2333                        struct hist_field *var_ref,
2334                        char *var_name)
2335 {
2336     struct hist_field *alias = NULL;
2337     unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;
2338
2339     alias = create_hist_field(hist_data, NULL, flags, var_name);
2340     if (!alias)
2341         return NULL;
2342
2343     alias->fn = var_ref->fn;
2344     alias->operands[0] = var_ref;
2345
2346     if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
2347         destroy_hist_field(alias, 0);
2348         return NULL;
2349     }
2350
2351     alias->var_ref_idx = var_ref->var_ref_idx;
2352
2353     return alias;
2354 }
2355
2356 static struct hist_field *parse_const(struct hist_trigger_data *hist_data,
2357                       char *str, char *var_name,
2358                       unsigned long *flags)
2359 {
2360     struct trace_array *tr = hist_data->event_file->tr;
2361     struct hist_field *field = NULL;
2362     u64 constant;
2363
2364     if (kstrtoull(str, 0, &constant)) {
2365         hist_err(tr, HIST_ERR_EXPECT_NUMBER, errpos(str));
2366         return NULL;
2367     }
2368
2369     *flags |= HIST_FIELD_FL_CONST;
2370     field = create_hist_field(hist_data, NULL, *flags, var_name);
2371     if (!field)
2372         return NULL;
2373
2374     field->constant = constant;
2375
2376     return field;
2377 }
2378
2379 static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
2380                      struct trace_event_file *file, char *str,
2381                      unsigned long *flags, char *var_name)
2382 {
2383     char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
2384     struct ftrace_event_field *field = NULL;
2385     struct hist_field *hist_field = NULL;
2386     unsigned long buckets = 0;
2387     int ret = 0;
2388
2389     if (isdigit(str[0])) {
2390         hist_field = parse_const(hist_data, str, var_name, flags);
2391         if (!hist_field) {
2392             ret = -EINVAL;
2393             goto out;
2394         }
2395         return hist_field;
2396     }
2397
2398     s = strchr(str, '.');
2399     if (s) {
2400         s = strchr(++s, '.');
2401         if (s) {
2402             ref_system = strsep(&str, ".");
2403             if (!str) {
2404                 ret = -EINVAL;
2405                 goto out;
2406             }
2407             ref_event = strsep(&str, ".");
2408             if (!str) {
2409                 ret = -EINVAL;
2410                 goto out;
2411             }
2412             ref_var = str;
2413         }
2414     }
2415
2416     s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
2417     if (!s) {
2418         hist_field = parse_var_ref(hist_data, ref_system,
2419                        ref_event, ref_var);
2420         if (hist_field) {
2421             if (var_name) {
2422                 hist_field = create_alias(hist_data, hist_field, var_name);
2423                 if (!hist_field) {
2424                     ret = -ENOMEM;
2425                     goto out;
2426                 }
2427             }
2428             return hist_field;
2429         }
2430     } else
2431         str = s;
2432
2433     field = parse_field(hist_data, file, str, flags, &buckets);
2434     if (IS_ERR(field)) {
2435         ret = PTR_ERR(field);
2436         goto out;
2437     }
2438
2439     hist_field = create_hist_field(hist_data, field, *flags, var_name);
2440     if (!hist_field) {
2441         ret = -ENOMEM;
2442         goto out;
2443     }
2444     hist_field->buckets = buckets;
2445
2446     return hist_field;
2447  out:
2448     return ERR_PTR(ret);
2449 }
2450
2451 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2452                      struct trace_event_file *file,
2453                      char *str, unsigned long flags,
2454                      char *var_name, unsigned int *n_subexprs);
2455
2456 static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
2457                       struct trace_event_file *file,
2458                       char *str, unsigned long flags,
2459                       char *var_name, unsigned int *n_subexprs)
2460 {
2461     struct hist_field *operand1, *expr = NULL;
2462     unsigned long operand_flags;
2463     int ret = 0;
2464     char *s;
2465
2466     /* Unary minus operator, increment n_subexprs */
2467     ++*n_subexprs;
2468
2469     /* we support only -(xxx) i.e. explicit parens required */
2470
2471     if (*n_subexprs > 3) {
2472         hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2473         ret = -EINVAL;
2474         goto free;
2475     }
2476
2477     str++; /* skip leading '-' */
2478
2479     s = strchr(str, '(');
2480     if (s)
2481         str++;
2482     else {
2483         ret = -EINVAL;
2484         goto free;
2485     }
2486
2487     s = strrchr(str, ')');
2488     if (s) {
2489          /* unary minus not supported in sub-expressions */
2490         if (*(s+1) != '\0') {
2491             hist_err(file->tr, HIST_ERR_UNARY_MINUS_SUBEXPR,
2492                  errpos(str));
2493             ret = -EINVAL;
2494             goto free;
2495         }
2496         *s = '\0';
2497     }
2498     else {
2499         ret = -EINVAL; /* no closing ')' */
2500         goto free;
2501     }
2502
2503     flags |= HIST_FIELD_FL_EXPR;
2504     expr = create_hist_field(hist_data, NULL, flags, var_name);
2505     if (!expr) {
2506         ret = -ENOMEM;
2507         goto free;
2508     }
2509
2510     operand_flags = 0;
2511     operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2512     if (IS_ERR(operand1)) {
2513         ret = PTR_ERR(operand1);
2514         goto free;
2515     }
2516     if (operand1->flags & HIST_FIELD_FL_STRING) {
2517         /* String type can not be the operand of unary operator. */
2518         hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2519         destroy_hist_field(operand1, 0);
2520         ret = -EINVAL;
2521         goto free;
2522     }
2523
2524     expr->flags |= operand1->flags &
2525         (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2526     expr->fn = hist_field_unary_minus;
2527     expr->operands[0] = operand1;
2528     expr->size = operand1->size;
2529     expr->is_signed = operand1->is_signed;
2530     expr->operator = FIELD_OP_UNARY_MINUS;
2531     expr->name = expr_str(expr, 0);
2532     expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2533     if (!expr->type) {
2534         ret = -ENOMEM;
2535         goto free;
2536     }
2537
2538     return expr;
2539  free:
2540     destroy_hist_field(expr, 0);
2541     return ERR_PTR(ret);
2542 }
2543
2544 /*
2545  * If the operands are var refs, return pointers the
2546  * variable(s) referenced in var1 and var2, else NULL.
2547  */
2548 static int check_expr_operands(struct trace_array *tr,
2549                    struct hist_field *operand1,
2550                    struct hist_field *operand2,
2551                    struct hist_field **var1,
2552                    struct hist_field **var2)
2553 {
2554     unsigned long operand1_flags = operand1->flags;
2555     unsigned long operand2_flags = operand2->flags;
2556
2557     if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
2558         (operand1_flags & HIST_FIELD_FL_ALIAS)) {
2559         struct hist_field *var;
2560
2561         var = find_var_field(operand1->var.hist_data, operand1->name);
2562         if (!var)
2563             return -EINVAL;
2564         operand1_flags = var->flags;
2565         *var1 = var;
2566     }
2567
2568     if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
2569         (operand2_flags & HIST_FIELD_FL_ALIAS)) {
2570         struct hist_field *var;
2571
2572         var = find_var_field(operand2->var.hist_data, operand2->name);
2573         if (!var)
2574             return -EINVAL;
2575         operand2_flags = var->flags;
2576         *var2 = var;
2577     }
2578
2579     if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
2580         (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
2581         hist_err(tr, HIST_ERR_TIMESTAMP_MISMATCH, 0);
2582         return -EINVAL;
2583     }
2584
2585     return 0;
2586 }
2587
2588 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2589                      struct trace_event_file *file,
2590                      char *str, unsigned long flags,
2591                      char *var_name, unsigned int *n_subexprs)
2592 {
2593     struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
2594     struct hist_field *var1 = NULL, *var2 = NULL;
2595     unsigned long operand_flags, operand2_flags;
2596     int field_op, ret = -EINVAL;
2597     char *sep, *operand1_str;
2598     hist_field_fn_t op_fn;
2599     bool combine_consts;
2600
2601     if (*n_subexprs > 3) {
2602         hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2603         return ERR_PTR(-EINVAL);
2604     }
2605
2606     field_op = contains_operator(str, &sep);
2607
2608     if (field_op == FIELD_OP_NONE)
2609         return parse_atom(hist_data, file, str, &flags, var_name);
2610
2611     if (field_op == FIELD_OP_UNARY_MINUS)
2612         return parse_unary(hist_data, file, str, flags, var_name, n_subexprs);
2613
2614     /* Binary operator found, increment n_subexprs */
2615     ++*n_subexprs;
2616
2617     /* Split the expression string at the root operator */
2618     if (!sep)
2619         return ERR_PTR(-EINVAL);
2620
2621     *sep = '\0';
2622     operand1_str = str;
2623     str = sep+1;
2624
2625     /* Binary operator requires both operands */
2626     if (*operand1_str == '\0' || *str == '\0')
2627         return ERR_PTR(-EINVAL);
2628
2629     operand_flags = 0;
2630
2631     /* LHS of string is an expression e.g. a+b in a+b+c */
2632     operand1 = parse_expr(hist_data, file, operand1_str, operand_flags, NULL, n_subexprs);
2633     if (IS_ERR(operand1))
2634         return ERR_CAST(operand1);
2635
2636     if (operand1->flags & HIST_FIELD_FL_STRING) {
2637         hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(operand1_str));
2638         ret = -EINVAL;
2639         goto free_op1;
2640     }
2641
2642     /* RHS of string is another expression e.g. c in a+b+c */
2643     operand_flags = 0;
2644     operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2645     if (IS_ERR(operand2)) {
2646         ret = PTR_ERR(operand2);
2647         goto free_op1;
2648     }
2649     if (operand2->flags & HIST_FIELD_FL_STRING) {
2650         hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2651         ret = -EINVAL;
2652         goto free_operands;
2653     }
2654
2655     switch (field_op) {
2656     case FIELD_OP_MINUS:
2657         op_fn = hist_field_minus;
2658         break;
2659     case FIELD_OP_PLUS:
2660         op_fn = hist_field_plus;
2661         break;
2662     case FIELD_OP_DIV:
2663         op_fn = hist_field_div;
2664         break;
2665     case FIELD_OP_MULT:
2666         op_fn = hist_field_mult;
2667         break;
2668     default:
2669         ret = -EINVAL;
2670         goto free_operands;
2671     }
2672
2673     ret = check_expr_operands(file->tr, operand1, operand2, &var1, &var2);
2674     if (ret)
2675         goto free_operands;
2676
2677     operand_flags = var1 ? var1->flags : operand1->flags;
2678     operand2_flags = var2 ? var2->flags : operand2->flags;
2679
2680     /*
2681      * If both operands are constant, the expression can be
2682      * collapsed to a single constant.
2683      */
2684     combine_consts = operand_flags & operand2_flags & HIST_FIELD_FL_CONST;
2685
2686     flags |= combine_consts ? HIST_FIELD_FL_CONST : HIST_FIELD_FL_EXPR;
2687
2688     flags |= operand1->flags &
2689         (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2690
2691     expr = create_hist_field(hist_data, NULL, flags, var_name);
2692     if (!expr) {
2693         ret = -ENOMEM;
2694         goto free_operands;
2695     }
2696
2697     operand1->read_once = true;
2698     operand2->read_once = true;
2699
2700     /* The operands are now owned and free'd by 'expr' */
2701     expr->operands[0] = operand1;
2702     expr->operands[1] = operand2;
2703
2704     if (field_op == FIELD_OP_DIV &&
2705             operand2_flags & HIST_FIELD_FL_CONST) {
2706         u64 divisor = var2 ? var2->constant : operand2->constant;
2707
2708         if (!divisor) {
2709             hist_err(file->tr, HIST_ERR_DIVISION_BY_ZERO, errpos(str));
2710             ret = -EDOM;
2711             goto free_expr;
2712         }
2713
2714         /*
2715          * Copy the divisor here so we don't have to look it up
2716          * later if this is a var ref
2717          */
2718         operand2->constant = divisor;
2719         op_fn = hist_field_get_div_fn(operand2);
2720     }
2721
2722     if (combine_consts) {
2723         if (var1)
2724             expr->operands[0] = var1;
2725         if (var2)
2726             expr->operands[1] = var2;
2727
2728         expr->constant = op_fn(expr, NULL, NULL, NULL, NULL);
2729
2730         expr->operands[0] = NULL;
2731         expr->operands[1] = NULL;
2732
2733         /*
2734          * var refs won't be destroyed immediately
2735          * See: destroy_hist_field()
2736          */
2737         destroy_hist_field(operand2, 0);
2738         destroy_hist_field(operand1, 0);
2739
2740         expr->name = expr_str(expr, 0);
2741     } else {
2742         expr->fn = op_fn;
2743
2744         /* The operand sizes should be the same, so just pick one */
2745         expr->size = operand1->size;
2746         expr->is_signed = operand1->is_signed;
2747
2748         expr->operator = field_op;
2749         expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2750         if (!expr->type) {
2751             ret = -ENOMEM;
2752             goto free_expr;
2753         }
2754
2755         expr->name = expr_str(expr, 0);
2756     }
2757
2758     return expr;
2759
2760 free_operands:
2761     destroy_hist_field(operand2, 0);
2762 free_op1:
2763     destroy_hist_field(operand1, 0);
2764     return ERR_PTR(ret);
2765
2766 free_expr:
2767     destroy_hist_field(expr, 0);
2768     return ERR_PTR(ret);
2769 }
2770
2771 static char *find_trigger_filter(struct hist_trigger_data *hist_data,
2772                  struct trace_event_file *file)
2773 {
2774     struct event_trigger_data *test;
2775
2776     lockdep_assert_held(&event_mutex);
2777
2778     list_for_each_entry(test, &file->triggers, list) {
2779         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2780             if (test->private_data == hist_data)
2781                 return test->filter_str;
2782         }
2783     }
2784
2785     return NULL;
2786 }
2787
2788 static struct event_command trigger_hist_cmd;
2789 static int event_hist_trigger_parse(struct event_command *cmd_ops,
2790                     struct trace_event_file *file,
2791                     char *glob, char *cmd,
2792                     char *param_and_filter);
2793
2794 static bool compatible_keys(struct hist_trigger_data *target_hist_data,
2795                 struct hist_trigger_data *hist_data,
2796                 unsigned int n_keys)
2797 {
2798     struct hist_field *target_hist_field, *hist_field;
2799     unsigned int n, i, j;
2800
2801     if (hist_data->n_fields - hist_data->n_vals != n_keys)
2802         return false;
2803
2804     i = hist_data->n_vals;
2805     j = target_hist_data->n_vals;
2806
2807     for (n = 0; n < n_keys; n++) {
2808         hist_field = hist_data->fields[i + n];
2809         target_hist_field = target_hist_data->fields[j + n];
2810
2811         if (strcmp(hist_field->type, target_hist_field->type) != 0)
2812             return false;
2813         if (hist_field->size != target_hist_field->size)
2814             return false;
2815         if (hist_field->is_signed != target_hist_field->is_signed)
2816             return false;
2817     }
2818
2819     return true;
2820 }
2821
2822 static struct hist_trigger_data *
2823 find_compatible_hist(struct hist_trigger_data *target_hist_data,
2824              struct trace_event_file *file)
2825 {
2826     struct hist_trigger_data *hist_data;
2827     struct event_trigger_data *test;
2828     unsigned int n_keys;
2829
2830     lockdep_assert_held(&event_mutex);
2831
2832     n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
2833
2834     list_for_each_entry(test, &file->triggers, list) {
2835         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2836             hist_data = test->private_data;
2837
2838             if (compatible_keys(target_hist_data, hist_data, n_keys))
2839                 return hist_data;
2840         }
2841     }
2842
2843     return NULL;
2844 }
2845
2846 static struct trace_event_file *event_file(struct trace_array *tr,
2847                        char *system, char *event_name)
2848 {
2849     struct trace_event_file *file;
2850
2851     file = __find_event_file(tr, system, event_name);
2852     if (!file)
2853         return ERR_PTR(-EINVAL);
2854
2855     return file;
2856 }
2857
2858 static struct hist_field *
2859 find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
2860              char *system, char *event_name, char *field_name)
2861 {
2862     struct hist_field *event_var;
2863     char *synthetic_name;
2864
2865     synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2866     if (!synthetic_name)
2867         return ERR_PTR(-ENOMEM);
2868
2869     strcpy(synthetic_name, "synthetic_");
2870     strcat(synthetic_name, field_name);
2871
2872     event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);
2873
2874     kfree(synthetic_name);
2875
2876     return event_var;
2877 }
2878
2879 /**
2880  * create_field_var_hist - Automatically create a histogram and var for a field
2881  * @target_hist_data: The target hist trigger
2882  * @subsys_name: Optional subsystem name
2883  * @event_name: Optional event name
2884  * @field_name: The name of the field (and the resulting variable)
2885  *
2886  * Hist trigger actions fetch data from variables, not directly from
2887  * events.  However, for convenience, users are allowed to directly
2888  * specify an event field in an action, which will be automatically
2889  * converted into a variable on their behalf.
2890  *
2891  * If a user specifies a field on an event that isn't the event the
2892  * histogram currently being defined (the target event histogram), the
2893  * only way that can be accomplished is if a new hist trigger is
2894  * created and the field variable defined on that.
2895  *
2896  * This function creates a new histogram compatible with the target
2897  * event (meaning a histogram with the same key as the target
2898  * histogram), and creates a variable for the specified field, but
2899  * with 'synthetic_' prepended to the variable name in order to avoid
2900  * collision with normal field variables.
2901  *
2902  * Return: The variable created for the field.
2903  */
2904 static struct hist_field *
2905 create_field_var_hist(struct hist_trigger_data *target_hist_data,
2906               char *subsys_name, char *event_name, char *field_name)
2907 {
2908     struct trace_array *tr = target_hist_data->event_file->tr;
2909     struct hist_trigger_data *hist_data;
2910     unsigned int i, n, first = true;
2911     struct field_var_hist *var_hist;
2912     struct trace_event_file *file;
2913     struct hist_field *key_field;
2914     struct hist_field *event_var;
2915     char *saved_filter;
2916     char *cmd;
2917     int ret;
2918
2919     if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
2920         hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
2921         return ERR_PTR(-EINVAL);
2922     }
2923
2924     file = event_file(tr, subsys_name, event_name);
2925
2926     if (IS_ERR(file)) {
2927         hist_err(tr, HIST_ERR_EVENT_FILE_NOT_FOUND, errpos(field_name));
2928         ret = PTR_ERR(file);
2929         return ERR_PTR(ret);
2930     }
2931
2932     /*
2933      * Look for a histogram compatible with target.  We'll use the
2934      * found histogram specification to create a new matching
2935      * histogram with our variable on it.  target_hist_data is not
2936      * yet a registered histogram so we can't use that.
2937      */
2938     hist_data = find_compatible_hist(target_hist_data, file);
2939     if (!hist_data) {
2940         hist_err(tr, HIST_ERR_HIST_NOT_FOUND, errpos(field_name));
2941         return ERR_PTR(-EINVAL);
2942     }
2943
2944     /* See if a synthetic field variable has already been created */
2945     event_var = find_synthetic_field_var(target_hist_data, subsys_name,
2946                          event_name, field_name);
2947     if (!IS_ERR_OR_NULL(event_var))
2948         return event_var;
2949
2950     var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
2951     if (!var_hist)
2952         return ERR_PTR(-ENOMEM);
2953
2954     cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2955     if (!cmd) {
2956         kfree(var_hist);
2957         return ERR_PTR(-ENOMEM);
2958     }
2959
2960     /* Use the same keys as the compatible histogram */
2961     strcat(cmd, "keys=");
2962
2963     for_each_hist_key_field(i, hist_data) {
2964         key_field = hist_data->fields[i];
2965         if (!first)
2966             strcat(cmd, ",");
2967         strcat(cmd, key_field->field->name);
2968         first = false;
2969     }
2970
2971     /* Create the synthetic field variable specification */
2972     strcat(cmd, ":synthetic_");
2973     strcat(cmd, field_name);
2974     strcat(cmd, "=");
2975     strcat(cmd, field_name);
2976
2977     /* Use the same filter as the compatible histogram */
2978     saved_filter = find_trigger_filter(hist_data, file);
2979     if (saved_filter) {
2980         strcat(cmd, " if ");
2981         strcat(cmd, saved_filter);
2982     }
2983
2984     var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
2985     if (!var_hist->cmd) {
2986         kfree(cmd);
2987         kfree(var_hist);
2988         return ERR_PTR(-ENOMEM);
2989     }
2990
2991     /* Save the compatible histogram information */
2992     var_hist->hist_data = hist_data;
2993
2994     /* Create the new histogram with our variable */
2995     ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
2996                        "", "hist", cmd);
2997     if (ret) {
2998         kfree(cmd);
2999         kfree(var_hist->cmd);
3000         kfree(var_hist);
3001         hist_err(tr, HIST_ERR_HIST_CREATE_FAIL, errpos(field_name));
3002         return ERR_PTR(ret);
3003     }
3004
3005     kfree(cmd);
3006
3007     /* If we can't find the variable, something went wrong */
3008     event_var = find_synthetic_field_var(target_hist_data, subsys_name,
3009                          event_name, field_name);
3010     if (IS_ERR_OR_NULL(event_var)) {
3011         kfree(var_hist->cmd);
3012         kfree(var_hist);
3013         hist_err(tr, HIST_ERR_SYNTH_VAR_NOT_FOUND, errpos(field_name));
3014         return ERR_PTR(-EINVAL);
3015     }
3016
3017     n = target_hist_data->n_field_var_hists;
3018     target_hist_data->field_var_hists[n] = var_hist;
3019     target_hist_data->n_field_var_hists++;
3020
3021     return event_var;
3022 }
3023
3024 static struct hist_field *
3025 find_target_event_var(struct hist_trigger_data *hist_data,
3026               char *subsys_name, char *event_name, char *var_name)
3027 {
3028     struct trace_event_file *file = hist_data->event_file;
3029     struct hist_field *hist_field = NULL;
3030
3031     if (subsys_name) {
3032         struct trace_event_call *call;
3033
3034         if (!event_name)
3035             return NULL;
3036
3037         call = file->event_call;
3038
3039         if (strcmp(subsys_name, call->class->system) != 0)
3040             return NULL;
3041
3042         if (strcmp(event_name, trace_event_name(call)) != 0)
3043             return NULL;
3044     }
3045
3046     hist_field = find_var_field(hist_data, var_name);
3047
3048     return hist_field;
3049 }
3050
3051 static inline void __update_field_vars(struct tracing_map_elt *elt,
3052                        struct trace_buffer *buffer,
3053                        struct ring_buffer_event *rbe,
3054                        void *rec,
3055                        struct field_var **field_vars,
3056                        unsigned int n_field_vars,
3057                        unsigned int field_var_str_start)
3058 {
3059     struct hist_elt_data *elt_data = elt->private_data;
3060     unsigned int i, j, var_idx;
3061     u64 var_val;
3062
3063     for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
3064         struct field_var *field_var = field_vars[i];
3065         struct hist_field *var = field_var->var;
3066         struct hist_field *val = field_var->val;
3067
3068         var_val = val->fn(val, elt, buffer, rbe, rec);
3069         var_idx = var->var.idx;
3070
3071         if (val->flags & HIST_FIELD_FL_STRING) {
3072             char *str = elt_data->field_var_str[j++];
3073             char *val_str = (char *)(uintptr_t)var_val;
3074             unsigned int size;
3075
3076             size = min(val->size, STR_VAR_LEN_MAX);
3077             strscpy(str, val_str, size);
3078             var_val = (u64)(uintptr_t)str;
3079         }
3080         tracing_map_set_var(elt, var_idx, var_val);
3081     }
3082 }
3083
3084 static void update_field_vars(struct hist_trigger_data *hist_data,
3085                   struct tracing_map_elt *elt,
3086                   struct trace_buffer *buffer,
3087                   struct ring_buffer_event *rbe,
3088                   void *rec)
3089 {
3090     __update_field_vars(elt, buffer, rbe, rec, hist_data->field_vars,
3091                 hist_data->n_field_vars, 0);
3092 }
3093
3094 static void save_track_data_vars(struct hist_trigger_data *hist_data,
3095                  struct tracing_map_elt *elt,
3096                  struct trace_buffer *buffer,  void *rec,
3097                  struct ring_buffer_event *rbe, void *key,
3098                  struct action_data *data, u64 *var_ref_vals)
3099 {
3100     __update_field_vars(elt, buffer, rbe, rec, hist_data->save_vars,
3101                 hist_data->n_save_vars, hist_data->n_field_var_str);
3102 }
3103
3104 static struct hist_field *create_var(struct hist_trigger_data *hist_data,
3105                      struct trace_event_file *file,
3106                      char *name, int size, const char *type)
3107 {
3108     struct hist_field *var;
3109     int idx;
3110
3111     if (find_var(hist_data, file, name) && !hist_data->remove) {
3112         var = ERR_PTR(-EINVAL);
3113         goto out;
3114     }
3115
3116     var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
3117     if (!var) {
3118         var = ERR_PTR(-ENOMEM);
3119         goto out;
3120     }
3121
3122     idx = tracing_map_add_var(hist_data->map);
3123     if (idx < 0) {
3124         kfree(var);
3125         var = ERR_PTR(-EINVAL);
3126         goto out;
3127     }
3128
3129     var->ref = 1;
3130     var->flags = HIST_FIELD_FL_VAR;
3131     var->var.idx = idx;
3132     var->var.hist_data = var->hist_data = hist_data;
3133     var->size = size;
3134     var->var.name = kstrdup(name, GFP_KERNEL);
3135     var->type = kstrdup_const(type, GFP_KERNEL);
3136     if (!var->var.name || !var->type) {
3137         kfree_const(var->type);
3138         kfree(var->var.name);
3139         kfree(var);
3140         var = ERR_PTR(-ENOMEM);
3141     }
3142  out:
3143     return var;
3144 }
3145
3146 static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
3147                       struct trace_event_file *file,
3148                       char *field_name)
3149 {
3150     struct hist_field *val = NULL, *var = NULL;
3151     unsigned long flags = HIST_FIELD_FL_VAR;
3152     struct trace_array *tr = file->tr;
3153     struct field_var *field_var;
3154     int ret = 0;
3155
3156     if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
3157         hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
3158         ret = -EINVAL;
3159         goto err;
3160     }
3161
3162     val = parse_atom(hist_data, file, field_name, &flags, NULL);
3163     if (IS_ERR(val)) {
3164         hist_err(tr, HIST_ERR_FIELD_VAR_PARSE_FAIL, errpos(field_name));
3165         ret = PTR_ERR(val);
3166         goto err;
3167     }
3168
3169     var = create_var(hist_data, file, field_name, val->size, val->type);
3170     if (IS_ERR(var)) {
3171         hist_err(tr, HIST_ERR_VAR_CREATE_FIND_FAIL, errpos(field_name));
3172         kfree(val);
3173         ret = PTR_ERR(var);
3174         goto err;
3175     }
3176
3177     field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
3178     if (!field_var) {
3179         kfree(val);
3180         kfree(var);
3181         ret =  -ENOMEM;
3182         goto err;
3183     }
3184
3185     field_var->var = var;
3186     field_var->val = val;
3187  out:
3188     return field_var;
3189  err:
3190     field_var = ERR_PTR(ret);
3191     goto out;
3192 }
3193
3194 /**
3195  * create_target_field_var - Automatically create a variable for a field
3196  * @target_hist_data: The target hist trigger
3197  * @subsys_name: Optional subsystem name
3198  * @event_name: Optional event name
3199  * @var_name: The name of the field (and the resulting variable)
3200  *
3201  * Hist trigger actions fetch data from variables, not directly from
3202  * events.  However, for convenience, users are allowed to directly
3203  * specify an event field in an action, which will be automatically
3204  * converted into a variable on their behalf.
3205
3206  * This function creates a field variable with the name var_name on
3207  * the hist trigger currently being defined on the target event.  If
3208  * subsys_name and event_name are specified, this function simply
3209  * verifies that they do in fact match the target event subsystem and
3210  * event name.
3211  *
3212  * Return: The variable created for the field.
3213  */
3214 static struct field_var *
3215 create_target_field_var(struct hist_trigger_data *target_hist_data,
3216             char *subsys_name, char *event_name, char *var_name)
3217 {
3218     struct trace_event_file *file = target_hist_data->event_file;
3219
3220     if (subsys_name) {
3221         struct trace_event_call *call;
3222
3223         if (!event_name)
3224             return NULL;
3225
3226         call = file->event_call;
3227
3228         if (strcmp(subsys_name, call->class->system) != 0)
3229             return NULL;
3230
3231         if (strcmp(event_name, trace_event_name(call)) != 0)
3232             return NULL;
3233     }
3234
3235     return create_field_var(target_hist_data, file, var_name);
3236 }
3237
3238 static bool check_track_val_max(u64 track_val, u64 var_val)
3239 {
3240     if (var_val <= track_val)
3241         return false;
3242
3243     return true;
3244 }
3245
3246 static bool check_track_val_changed(u64 track_val, u64 var_val)
3247 {
3248     if (var_val == track_val)
3249         return false;
3250
3251     return true;
3252 }
3253
3254 static u64 get_track_val(struct hist_trigger_data *hist_data,
3255              struct tracing_map_elt *elt,
3256              struct action_data *data)
3257 {
3258     unsigned int track_var_idx = data->track_data.track_var->var.idx;
3259     u64 track_val;
3260
3261     track_val = tracing_map_read_var(elt, track_var_idx);
3262
3263     return track_val;
3264 }
3265
3266 static void save_track_val(struct hist_trigger_data *hist_data,
3267                struct tracing_map_elt *elt,
3268                struct action_data *data, u64 var_val)
3269 {
3270     unsigned int track_var_idx = data->track_data.track_var->var.idx;
3271
3272     tracing_map_set_var(elt, track_var_idx, var_val);
3273 }
3274
3275 static void save_track_data(struct hist_trigger_data *hist_data,
3276                 struct tracing_map_elt *elt,
3277                 struct trace_buffer *buffer, void *rec,
3278                 struct ring_buffer_event *rbe, void *key,
3279                 struct action_data *data, u64 *var_ref_vals)
3280 {
3281     if (data->track_data.save_data)
3282         data->track_data.save_data(hist_data, elt, buffer, rec, rbe,
3283                        key, data, var_ref_vals);
3284 }
3285
3286 static bool check_track_val(struct tracing_map_elt *elt,
3287                 struct action_data *data,
3288                 u64 var_val)
3289 {
3290     struct hist_trigger_data *hist_data;
3291     u64 track_val;
3292
3293     hist_data = data->track_data.track_var->hist_data;
3294     track_val = get_track_val(hist_data, elt, data);
3295
3296     return data->track_data.check_val(track_val, var_val);
3297 }
3298
3299 #ifdef CONFIG_TRACER_SNAPSHOT
3300 static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3301 {
3302     /* called with tr->max_lock held */
3303     struct track_data *track_data = tr->cond_snapshot->cond_data;
3304     struct hist_elt_data *elt_data, *track_elt_data;
3305     struct snapshot_context *context = cond_data;
3306     struct action_data *action;
3307     u64 track_val;
3308
3309     if (!track_data)
3310         return false;
3311
3312     action = track_data->action_data;
3313
3314     track_val = get_track_val(track_data->hist_data, context->elt,
3315                   track_data->action_data);
3316
3317     if (!action->track_data.check_val(track_data->track_val, track_val))
3318         return false;
3319
3320     track_data->track_val = track_val;
3321     memcpy(track_data->key, context->key, track_data->key_len);
3322
3323     elt_data = context->elt->private_data;
3324     track_elt_data = track_data->elt.private_data;
3325     if (elt_data->comm)
3326         strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
3327
3328     track_data->updated = true;
3329
3330     return true;
3331 }
3332
3333 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3334                      struct tracing_map_elt *elt,
3335                      struct trace_buffer *buffer, void *rec,
3336                      struct ring_buffer_event *rbe, void *key,
3337                      struct action_data *data,
3338                      u64 *var_ref_vals)
3339 {
3340     struct trace_event_file *file = hist_data->event_file;
3341     struct snapshot_context context;
3342
3343     context.elt = elt;
3344     context.key = key;
3345
3346     tracing_snapshot_cond(file->tr, &context);
3347 }
3348
3349 static void hist_trigger_print_key(struct seq_file *m,
3350                    struct hist_trigger_data *hist_data,
3351                    void *key,
3352                    struct tracing_map_elt *elt);
3353
3354 static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
3355 {
3356     unsigned int i;
3357
3358     if (!hist_data->n_actions)
3359         return NULL;
3360
3361     for (i = 0; i < hist_data->n_actions; i++) {
3362         struct action_data *data = hist_data->actions[i];
3363
3364         if (data->action == ACTION_SNAPSHOT)
3365             return data;
3366     }
3367
3368     return NULL;
3369 }
3370
3371 static void track_data_snapshot_print(struct seq_file *m,
3372                       struct hist_trigger_data *hist_data)
3373 {
3374     struct trace_event_file *file = hist_data->event_file;
3375     struct track_data *track_data;
3376     struct action_data *action;
3377
3378     track_data = tracing_cond_snapshot_data(file->tr);
3379     if (!track_data)
3380         return;
3381
3382     if (!track_data->updated)
3383         return;
3384
3385     action = snapshot_action(hist_data);
3386     if (!action)
3387         return;
3388
3389     seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
3390     seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
3391            action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
3392            action->track_data.var_str, track_data->track_val);
3393
3394     seq_puts(m, "\ttriggered by event with key: ");
3395     hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
3396     seq_putc(m, '\n');
3397 }
3398 #else
3399 static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3400 {
3401     return false;
3402 }
3403 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3404                      struct tracing_map_elt *elt,
3405                      struct trace_buffer *buffer, void *rec,
3406                      struct ring_buffer_event *rbe, void *key,
3407                      struct action_data *data,
3408                      u64 *var_ref_vals) {}
3409 static void track_data_snapshot_print(struct seq_file *m,
3410                       struct hist_trigger_data *hist_data) {}
3411 #endif /* CONFIG_TRACER_SNAPSHOT */
3412
3413 static void track_data_print(struct seq_file *m,
3414                  struct hist_trigger_data *hist_data,
3415                  struct tracing_map_elt *elt,
3416                  struct action_data *data)
3417 {
3418     u64 track_val = get_track_val(hist_data, elt, data);
3419     unsigned int i, save_var_idx;
3420
3421     if (data->handler == HANDLER_ONMAX)
3422         seq_printf(m, "\n\tmax: %10llu", track_val);
3423     else if (data->handler == HANDLER_ONCHANGE)
3424         seq_printf(m, "\n\tchanged: %10llu", track_val);
3425
3426     if (data->action == ACTION_SNAPSHOT)
3427         return;
3428
3429     for (i = 0; i < hist_data->n_save_vars; i++) {
3430         struct hist_field *save_val = hist_data->save_vars[i]->val;
3431         struct hist_field *save_var = hist_data->save_vars[i]->var;
3432         u64 val;
3433
3434         save_var_idx = save_var->var.idx;
3435
3436         val = tracing_map_read_var(elt, save_var_idx);
3437
3438         if (save_val->flags & HIST_FIELD_FL_STRING) {
3439             seq_printf(m, "  %s: %-32s", save_var->var.name,
3440                    (char *)(uintptr_t)(val));
3441         } else
3442             seq_printf(m, "  %s: %10llu", save_var->var.name, val);
3443     }
3444 }
3445
3446 static void ontrack_action(struct hist_trigger_data *hist_data,
3447                struct tracing_map_elt *elt,
3448                struct trace_buffer *buffer, void *rec,
3449                struct ring_buffer_event *rbe, void *key,
3450                struct action_data *data, u64 *var_ref_vals)
3451 {
3452     u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];
3453
3454     if (check_track_val(elt, data, var_val)) {
3455         save_track_val(hist_data, elt, data, var_val);
3456         save_track_data(hist_data, elt, buffer, rec, rbe,
3457                 key, data, var_ref_vals);
3458     }
3459 }
3460
3461 static void action_data_destroy(struct action_data *data)
3462 {
3463     unsigned int i;
3464
3465     lockdep_assert_held(&event_mutex);
3466
3467     kfree(data->action_name);
3468
3469     for (i = 0; i < data->n_params; i++)
3470         kfree(data->params[i]);
3471
3472     if (data->synth_event)
3473         data->synth_event->ref--;
3474
3475     kfree(data->synth_event_name);
3476
3477     kfree(data);
3478 }
3479
3480 static void track_data_destroy(struct hist_trigger_data *hist_data,
3481                    struct action_data *data)
3482 {
3483     struct trace_event_file *file = hist_data->event_file;
3484
3485     destroy_hist_field(data->track_data.track_var, 0);
3486
3487     if (data->action == ACTION_SNAPSHOT) {
3488         struct track_data *track_data;
3489
3490         track_data = tracing_cond_snapshot_data(file->tr);
3491         if (track_data && track_data->hist_data == hist_data) {
3492             tracing_snapshot_cond_disable(file->tr);
3493             track_data_free(track_data);
3494         }
3495     }
3496
3497     kfree(data->track_data.var_str);
3498
3499     action_data_destroy(data);
3500 }
3501
3502 static int action_create(struct hist_trigger_data *hist_data,
3503              struct action_data *data);
3504
3505 static int track_data_create(struct hist_trigger_data *hist_data,
3506                  struct action_data *data)
3507 {
3508     struct hist_field *var_field, *ref_field, *track_var = NULL;
3509     struct trace_event_file *file = hist_data->event_file;
3510     struct trace_array *tr = file->tr;
3511     char *track_data_var_str;
3512     int ret = 0;
3513
3514     track_data_var_str = data->track_data.var_str;
3515     if (track_data_var_str[0] != '$') {
3516         hist_err(tr, HIST_ERR_ONX_NOT_VAR, errpos(track_data_var_str));
3517         return -EINVAL;
3518     }
3519     track_data_var_str++;
3520
3521     var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
3522     if (!var_field) {
3523         hist_err(tr, HIST_ERR_ONX_VAR_NOT_FOUND, errpos(track_data_var_str));
3524         return -EINVAL;
3525     }
3526
3527     ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
3528     if (!ref_field)
3529         return -ENOMEM;
3530
3531     data->track_data.var_ref = ref_field;
3532
3533     if (data->handler == HANDLER_ONMAX)
3534         track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
3535     if (IS_ERR(track_var)) {
3536         hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3537         ret = PTR_ERR(track_var);
3538         goto out;
3539     }
3540
3541     if (data->handler == HANDLER_ONCHANGE)
3542         track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
3543     if (IS_ERR(track_var)) {
3544         hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3545         ret = PTR_ERR(track_var);
3546         goto out;
3547     }
3548     data->track_data.track_var = track_var;
3549
3550     ret = action_create(hist_data, data);
3551  out:
3552     return ret;
3553 }
3554
3555 static int parse_action_params(struct trace_array *tr, char *params,
3556                    struct action_data *data)
3557 {
3558     char *param, *saved_param;
3559     bool first_param = true;
3560     int ret = 0;
3561
3562     while (params) {
3563         if (data->n_params >= SYNTH_FIELDS_MAX) {
3564             hist_err(tr, HIST_ERR_TOO_MANY_PARAMS, 0);
3565             goto out;
3566         }
3567
3568         param = strsep(&params, ",");
3569         if (!param) {
3570             hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, 0);
3571             ret = -EINVAL;
3572             goto out;
3573         }
3574
3575         param = strstrip(param);
3576         if (strlen(param) < 2) {
3577             hist_err(tr, HIST_ERR_INVALID_PARAM, errpos(param));
3578             ret = -EINVAL;
3579             goto out;
3580         }
3581
3582         saved_param = kstrdup(param, GFP_KERNEL);
3583         if (!saved_param) {
3584             ret = -ENOMEM;
3585             goto out;
3586         }
3587
3588         if (first_param && data->use_trace_keyword) {
3589             data->synth_event_name = saved_param;
3590             first_param = false;
3591             continue;
3592         }
3593         first_param = false;
3594
3595         data->params[data->n_params++] = saved_param;
3596     }
3597  out:
3598     return ret;
3599 }
3600
3601 static int action_parse(struct trace_array *tr, char *str, struct action_data *data,
3602             enum handler_id handler)
3603 {
3604     char *action_name;
3605     int ret = 0;
3606
3607     strsep(&str, ".");
3608     if (!str) {
3609         hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3610         ret = -EINVAL;
3611         goto out;
3612     }
3613
3614     action_name = strsep(&str, "(");
3615     if (!action_name || !str) {
3616         hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3617         ret = -EINVAL;
3618         goto out;
3619     }
3620
3621     if (str_has_prefix(action_name, "save")) {
3622         char *params = strsep(&str, ")");
3623
3624         if (!params) {
3625             hist_err(tr, HIST_ERR_NO_SAVE_PARAMS, 0);
3626             ret = -EINVAL;
3627             goto out;
3628         }
3629
3630         ret = parse_action_params(tr, params, data);
3631         if (ret)
3632             goto out;
3633
3634         if (handler == HANDLER_ONMAX)
3635             data->track_data.check_val = check_track_val_max;
3636         else if (handler == HANDLER_ONCHANGE)
3637             data->track_data.check_val = check_track_val_changed;
3638         else {
3639             hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3640             ret = -EINVAL;
3641             goto out;
3642         }
3643
3644         data->track_data.save_data = save_track_data_vars;
3645         data->fn = ontrack_action;
3646         data->action = ACTION_SAVE;
3647     } else if (str_has_prefix(action_name, "snapshot")) {
3648         char *params = strsep(&str, ")");
3649
3650         if (!str) {
3651             hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(params));
3652             ret = -EINVAL;
3653             goto out;
3654         }
3655
3656         if (handler == HANDLER_ONMAX)
3657             data->track_data.check_val = check_track_val_max;
3658         else if (handler == HANDLER_ONCHANGE)
3659             data->track_data.check_val = check_track_val_changed;
3660         else {
3661             hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3662             ret = -EINVAL;
3663             goto out;
3664         }
3665
3666         data->track_data.save_data = save_track_data_snapshot;
3667         data->fn = ontrack_action;
3668         data->action = ACTION_SNAPSHOT;
3669     } else {
3670         char *params = strsep(&str, ")");
3671
3672         if (str_has_prefix(action_name, "trace"))
3673             data->use_trace_keyword = true;
3674
3675         if (params) {
3676             ret = parse_action_params(tr, params, data);
3677             if (ret)
3678                 goto out;
3679         }
3680
3681         if (handler == HANDLER_ONMAX)
3682             data->track_data.check_val = check_track_val_max;
3683         else if (handler == HANDLER_ONCHANGE)
3684             data->track_data.check_val = check_track_val_changed;
3685
3686         if (handler != HANDLER_ONMATCH) {
3687             data->track_data.save_data = action_trace;
3688             data->fn = ontrack_action;
3689         } else
3690             data->fn = action_trace;
3691
3692         data->action = ACTION_TRACE;
3693     }
3694
3695     data->action_name = kstrdup(action_name, GFP_KERNEL);
3696     if (!data->action_name) {
3697         ret = -ENOMEM;
3698         goto out;
3699     }
3700
3701     data->handler = handler;
3702  out:
3703     return ret;
3704 }
3705
3706 static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
3707                         char *str, enum handler_id handler)
3708 {
3709     struct action_data *data;
3710     int ret = -EINVAL;
3711     char *var_str;
3712
3713     data = kzalloc(sizeof(*data), GFP_KERNEL);
3714     if (!data)
3715         return ERR_PTR(-ENOMEM);
3716
3717     var_str = strsep(&str, ")");
3718     if (!var_str || !str) {
3719         ret = -EINVAL;
3720         goto free;
3721     }
3722
3723     data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
3724     if (!data->track_data.var_str) {
3725         ret = -ENOMEM;
3726         goto free;
3727     }
3728
3729     ret = action_parse(hist_data->event_file->tr, str, data, handler);
3730     if (ret)
3731         goto free;
3732  out:
3733     return data;
3734  free:
3735     track_data_destroy(hist_data, data);
3736     data = ERR_PTR(ret);
3737     goto out;
3738 }
3739
3740 static void onmatch_destroy(struct action_data *data)
3741 {
3742     kfree(data->match_data.event);
3743     kfree(data->match_data.event_system);
3744
3745     action_data_destroy(data);
3746 }
3747
3748 static void destroy_field_var(struct field_var *field_var)
3749 {
3750     if (!field_var)
3751         return;
3752
3753     destroy_hist_field(field_var->var, 0);
3754     destroy_hist_field(field_var->val, 0);
3755
3756     kfree(field_var);
3757 }
3758
3759 static void destroy_field_vars(struct hist_trigger_data *hist_data)
3760 {
3761     unsigned int i;
3762
3763     for (i = 0; i < hist_data->n_field_vars; i++)
3764         destroy_field_var(hist_data->field_vars[i]);
3765
3766     for (i = 0; i < hist_data->n_save_vars; i++)
3767         destroy_field_var(hist_data->save_vars[i]);
3768 }
3769
3770 static void save_field_var(struct hist_trigger_data *hist_data,
3771                struct field_var *field_var)
3772 {
3773     hist_data->field_vars[hist_data->n_field_vars++] = field_var;
3774
3775     if (field_var->val->flags & HIST_FIELD_FL_STRING)
3776         hist_data->n_field_var_str++;
3777 }
3778
3779
3780 static int check_synth_field(struct synth_event *event,
3781                  struct hist_field *hist_field,
3782                  unsigned int field_pos)
3783 {
3784     struct synth_field *field;
3785
3786     if (field_pos >= event->n_fields)
3787         return -EINVAL;
3788
3789     field = event->fields[field_pos];
3790
3791     /*
3792      * A dynamic string synth field can accept static or
3793      * dynamic. A static string synth field can only accept a
3794      * same-sized static string, which is checked for later.
3795      */
3796     if (strstr(hist_field->type, "char[") && field->is_string
3797         && field->is_dynamic)
3798         return 0;
3799
3800     if (strcmp(field->type, hist_field->type) != 0) {
3801         if (field->size != hist_field->size ||
3802             (!field->is_string && field->is_signed != hist_field->is_signed))
3803             return -EINVAL;
3804     }
3805
3806     return 0;
3807 }
3808
3809 static struct hist_field *
3810 trace_action_find_var(struct hist_trigger_data *hist_data,
3811               struct action_data *data,
3812               char *system, char *event, char *var)
3813 {
3814     struct trace_array *tr = hist_data->event_file->tr;
3815     struct hist_field *hist_field;
3816
3817     var++; /* skip '$' */
3818
3819     hist_field = find_target_event_var(hist_data, system, event, var);
3820     if (!hist_field) {
3821         if (!system && data->handler == HANDLER_ONMATCH) {
3822             system = data->match_data.event_system;
3823             event = data->match_data.event;
3824         }
3825
3826         hist_field = find_event_var(hist_data, system, event, var);
3827     }
3828
3829     if (!hist_field)
3830         hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, errpos(var));
3831
3832     return hist_field;
3833 }
3834
3835 static struct hist_field *
3836 trace_action_create_field_var(struct hist_trigger_data *hist_data,
3837                   struct action_data *data, char *system,
3838                   char *event, char *var)
3839 {
3840     struct hist_field *hist_field = NULL;
3841     struct field_var *field_var;
3842
3843     /*
3844      * First try to create a field var on the target event (the
3845      * currently being defined).  This will create a variable for
3846      * unqualified fields on the target event, or if qualified,
3847      * target fields that have qualified names matching the target.
3848      */
3849     field_var = create_target_field_var(hist_data, system, event, var);
3850
3851     if (field_var && !IS_ERR(field_var)) {
3852         save_field_var(hist_data, field_var);
3853         hist_field = field_var->var;
3854     } else {
3855         field_var = NULL;
3856         /*
3857          * If no explicit system.event is specified, default to
3858          * looking for fields on the onmatch(system.event.xxx)
3859          * event.
3860          */
3861         if (!system && data->handler == HANDLER_ONMATCH) {
3862             system = data->match_data.event_system;
3863             event = data->match_data.event;
3864         }
3865
3866         if (!event)
3867             goto free;
3868         /*
3869          * At this point, we're looking at a field on another
3870          * event.  Because we can't modify a hist trigger on
3871          * another event to add a variable for a field, we need
3872          * to create a new trigger on that event and create the
3873          * variable at the same time.
3874          */
3875         hist_field = create_field_var_hist(hist_data, system, event, var);
3876         if (IS_ERR(hist_field))
3877             goto free;
3878     }
3879  out:
3880     return hist_field;
3881  free:
3882     destroy_field_var(field_var);
3883     hist_field = NULL;
3884     goto out;
3885 }
3886
3887 static int trace_action_create(struct hist_trigger_data *hist_data,
3888                    struct action_data *data)
3889 {
3890     struct trace_array *tr = hist_data->event_file->tr;
3891     char *event_name, *param, *system = NULL;
3892     struct hist_field *hist_field, *var_ref;
3893     unsigned int i;
3894     unsigned int field_pos = 0;
3895     struct synth_event *event;
3896     char *synth_event_name;
3897     int var_ref_idx, ret = 0;
3898
3899     lockdep_assert_held(&event_mutex);
3900
3901     if (data->use_trace_keyword)
3902         synth_event_name = data->synth_event_name;
3903     else
3904         synth_event_name = data->action_name;
3905
3906     event = find_synth_event(synth_event_name);
3907     if (!event) {
3908         hist_err(tr, HIST_ERR_SYNTH_EVENT_NOT_FOUND, errpos(synth_event_name));
3909         return -EINVAL;
3910     }
3911
3912     event->ref++;
3913
3914     for (i = 0; i < data->n_params; i++) {
3915         char *p;
3916
3917         p = param = kstrdup(data->params[i], GFP_KERNEL);
3918         if (!param) {
3919             ret = -ENOMEM;
3920             goto err;
3921         }
3922
3923         system = strsep(&param, ".");
3924         if (!param) {
3925             param = (char *)system;
3926             system = event_name = NULL;
3927         } else {
3928             event_name = strsep(&param, ".");
3929             if (!param) {
3930                 kfree(p);
3931                 ret = -EINVAL;
3932                 goto err;
3933             }
3934         }
3935
3936         if (param[0] == '$')
3937             hist_field = trace_action_find_var(hist_data, data,
3938                                system, event_name,
3939                                param);
3940         else
3941             hist_field = trace_action_create_field_var(hist_data,
3942                                    data,
3943                                    system,
3944                                    event_name,
3945                                    param);
3946
3947         if (!hist_field) {
3948             kfree(p);
3949             ret = -EINVAL;
3950             goto err;
3951         }
3952
3953         if (check_synth_field(event, hist_field, field_pos) == 0) {
3954             var_ref = create_var_ref(hist_data, hist_field,
3955                          system, event_name);
3956             if (!var_ref) {
3957                 kfree(p);
3958                 ret = -ENOMEM;
3959                 goto err;
3960             }
3961
3962             var_ref_idx = find_var_ref_idx(hist_data, var_ref);
3963             if (WARN_ON(var_ref_idx < 0)) {
3964                 kfree(p);
3965                 ret = var_ref_idx;
3966                 goto err;
3967             }
3968
3969             data->var_ref_idx[i] = var_ref_idx;
3970
3971             field_pos++;
3972             kfree(p);
3973             continue;
3974         }
3975
3976         hist_err(tr, HIST_ERR_SYNTH_TYPE_MISMATCH, errpos(param));
3977         kfree(p);
3978         ret = -EINVAL;
3979         goto err;
3980     }
3981
3982     if (field_pos != event->n_fields) {
3983         hist_err(tr, HIST_ERR_SYNTH_COUNT_MISMATCH, errpos(event->name));
3984         ret = -EINVAL;
3985         goto err;
3986     }
3987
3988     data->synth_event = event;
3989  out:
3990     return ret;
3991  err:
3992     event->ref--;
3993
3994     goto out;
3995 }
3996
3997 static int action_create(struct hist_trigger_data *hist_data,
3998              struct action_data *data)
3999 {
4000     struct trace_event_file *file = hist_data->event_file;
4001     struct trace_array *tr = file->tr;
4002     struct track_data *track_data;
4003     struct field_var *field_var;
4004     unsigned int i;
4005     char *param;
4006     int ret = 0;
4007
4008     if (data->action == ACTION_TRACE)
4009         return trace_action_create(hist_data, data);
4010
4011     if (data->action == ACTION_SNAPSHOT) {
4012         track_data = track_data_alloc(hist_data->key_size, data, hist_data);
4013         if (IS_ERR(track_data)) {
4014             ret = PTR_ERR(track_data);
4015             goto out;
4016         }
4017
4018         ret = tracing_snapshot_cond_enable(file->tr, track_data,
4019                            cond_snapshot_update);
4020         if (ret)
4021             track_data_free(track_data);
4022
4023         goto out;
4024     }
4025
4026     if (data->action == ACTION_SAVE) {
4027         if (hist_data->n_save_vars) {
4028             ret = -EEXIST;
4029             hist_err(tr, HIST_ERR_TOO_MANY_SAVE_ACTIONS, 0);
4030             goto out;
4031         }
4032
4033         for (i = 0; i < data->n_params; i++) {
4034             param = kstrdup(data->params[i], GFP_KERNEL);
4035             if (!param) {
4036                 ret = -ENOMEM;
4037                 goto out;
4038             }
4039
4040             field_var = create_target_field_var(hist_data, NULL, NULL, param);
4041             if (IS_ERR(field_var)) {
4042                 hist_err(tr, HIST_ERR_FIELD_VAR_CREATE_FAIL,
4043                      errpos(param));
4044                 ret = PTR_ERR(field_var);
4045                 kfree(param);
4046                 goto out;
4047             }
4048
4049             hist_data->save_vars[hist_data->n_save_vars++] = field_var;
4050             if (field_var->val->flags & HIST_FIELD_FL_STRING)
4051                 hist_data->n_save_var_str++;
4052             kfree(param);
4053         }
4054     }
4055  out:
4056     return ret;
4057 }
4058
4059 static int onmatch_create(struct hist_trigger_data *hist_data,
4060               struct action_data *data)
4061 {
4062     return action_create(hist_data, data);
4063 }
4064
4065 static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
4066 {
4067     char *match_event, *match_event_system;
4068     struct action_data *data;
4069     int ret = -EINVAL;
4070
4071     data = kzalloc(sizeof(*data), GFP_KERNEL);
4072     if (!data)
4073         return ERR_PTR(-ENOMEM);
4074
4075     match_event = strsep(&str, ")");
4076     if (!match_event || !str) {
4077         hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(match_event));
4078         goto free;
4079     }
4080
4081     match_event_system = strsep(&match_event, ".");
4082     if (!match_event) {
4083         hist_err(tr, HIST_ERR_SUBSYS_NOT_FOUND, errpos(match_event_system));
4084         goto free;
4085     }
4086
4087     if (IS_ERR(event_file(tr, match_event_system, match_event))) {
4088         hist_err(tr, HIST_ERR_INVALID_SUBSYS_EVENT, errpos(match_event));
4089         goto free;
4090     }
4091
4092     data->match_data.event = kstrdup(match_event, GFP_KERNEL);
4093     if (!data->match_data.event) {
4094         ret = -ENOMEM;
4095         goto free;
4096     }
4097
4098     data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
4099     if (!data->match_data.event_system) {
4100         ret = -ENOMEM;
4101         goto free;
4102     }
4103
4104     ret = action_parse(tr, str, data, HANDLER_ONMATCH);
4105     if (ret)
4106         goto free;
4107  out:
4108     return data;
4109  free:
4110     onmatch_destroy(data);
4111     data = ERR_PTR(ret);
4112     goto out;
4113 }
4114
4115 static int create_hitcount_val(struct hist_trigger_data *hist_data)
4116 {
4117     hist_data->fields[HITCOUNT_IDX] =
4118         create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
4119     if (!hist_data->fields[HITCOUNT_IDX])
4120         return -ENOMEM;
4121
4122     hist_data->n_vals++;
4123     hist_data->n_fields++;
4124
4125     if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
4126         return -EINVAL;
4127
4128     return 0;
4129 }
4130
4131 static int __create_val_field(struct hist_trigger_data *hist_data,
4132                   unsigned int val_idx,
4133                   struct trace_event_file *file,
4134                   char *var_name, char *field_str,
4135                   unsigned long flags)
4136 {
4137     struct hist_field *hist_field;
4138     int ret = 0, n_subexprs = 0;
4139
4140     hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs);
4141     if (IS_ERR(hist_field)) {
4142         ret = PTR_ERR(hist_field);
4143         goto out;
4144     }
4145
4146     hist_data->fields[val_idx] = hist_field;
4147
4148     ++hist_data->n_vals;
4149     ++hist_data->n_fields;
4150
4151     if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4152         ret = -EINVAL;
4153  out:
4154     return ret;
4155 }
4156
4157 static int create_val_field(struct hist_trigger_data *hist_data,
4158                 unsigned int val_idx,
4159                 struct trace_event_file *file,
4160                 char *field_str)
4161 {
4162     if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
4163         return -EINVAL;
4164
4165     return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
4166 }
4167
4168 static const char no_comm[] = "(no comm)";
4169
4170 static u64 hist_field_execname(struct hist_field *hist_field,
4171                    struct tracing_map_elt *elt,
4172                    struct trace_buffer *buffer,
4173                    struct ring_buffer_event *rbe,
4174                    void *event)
4175 {
4176     struct hist_elt_data *elt_data;
4177
4178     if (WARN_ON_ONCE(!elt))
4179         return (u64)(unsigned long)no_comm;
4180
4181     elt_data = elt->private_data;
4182
4183     if (WARN_ON_ONCE(!elt_data->comm))
4184         return (u64)(unsigned long)no_comm;
4185
4186     return (u64)(unsigned long)(elt_data->comm);
4187 }
4188
4189 /* Convert a var that points to common_pid.execname to a string */
4190 static void update_var_execname(struct hist_field *hist_field)
4191 {
4192     hist_field->flags = HIST_FIELD_FL_STRING | HIST_FIELD_FL_VAR |
4193         HIST_FIELD_FL_EXECNAME;
4194     hist_field->size = MAX_FILTER_STR_VAL;
4195     hist_field->is_signed = 0;
4196
4197     kfree_const(hist_field->type);
4198     hist_field->type = "char[]";
4199
4200     hist_field->fn = hist_field_execname;
4201 }
4202
4203 static int create_var_field(struct hist_trigger_data *hist_data,
4204                 unsigned int val_idx,
4205                 struct trace_event_file *file,
4206                 char *var_name, char *expr_str)
4207 {
4208     struct trace_array *tr = hist_data->event_file->tr;
4209     unsigned long flags = 0;
4210     int ret;
4211
4212     if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4213         return -EINVAL;
4214
4215     if (find_var(hist_data, file, var_name) && !hist_data->remove) {
4216         hist_err(tr, HIST_ERR_DUPLICATE_VAR, errpos(var_name));
4217         return -EINVAL;
4218     }
4219
4220     flags |= HIST_FIELD_FL_VAR;
4221     hist_data->n_vars++;
4222     if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
4223         return -EINVAL;
4224
4225     ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
4226
4227     if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
4228         update_var_execname(hist_data->fields[val_idx]);
4229
4230     if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
4231         hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
4232
4233     return ret;
4234 }
4235
4236 static int create_val_fields(struct hist_trigger_data *hist_data,
4237                  struct trace_event_file *file)
4238 {
4239     char *fields_str, *field_str;
4240     unsigned int i, j = 1;
4241     int ret;
4242
4243     ret = create_hitcount_val(hist_data);
4244     if (ret)
4245         goto out;
4246
4247     fields_str = hist_data->attrs->vals_str;
4248     if (!fields_str)
4249         goto out;
4250
4251     for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
4252              j < TRACING_MAP_VALS_MAX; i++) {
4253         field_str = strsep(&fields_str, ",");
4254         if (!field_str)
4255             break;
4256
4257         if (strcmp(field_str, "hitcount") == 0)
4258             continue;
4259
4260         ret = create_val_field(hist_data, j++, file, field_str);
4261         if (ret)
4262             goto out;
4263     }
4264
4265     if (fields_str && (strcmp(fields_str, "hitcount") != 0))
4266         ret = -EINVAL;
4267  out:
4268     return ret;
4269 }
4270
4271 static int create_key_field(struct hist_trigger_data *hist_data,
4272                 unsigned int key_idx,
4273                 unsigned int key_offset,
4274                 struct trace_event_file *file,
4275                 char *field_str)
4276 {
4277     struct trace_array *tr = hist_data->event_file->tr;
4278     struct hist_field *hist_field = NULL;
4279     unsigned long flags = 0;
4280     unsigned int key_size;
4281     int ret = 0, n_subexprs = 0;
4282
4283     if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
4284         return -EINVAL;
4285
4286     flags |= HIST_FIELD_FL_KEY;
4287
4288     if (strcmp(field_str, "stacktrace") == 0) {
4289         flags |= HIST_FIELD_FL_STACKTRACE;
4290         key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
4291         hist_field = create_hist_field(hist_data, NULL, flags, NULL);
4292     } else {
4293         hist_field = parse_expr(hist_data, file, field_str, flags,
4294                     NULL, &n_subexprs);
4295         if (IS_ERR(hist_field)) {
4296             ret = PTR_ERR(hist_field);
4297             goto out;
4298         }
4299
4300         if (field_has_hist_vars(hist_field, 0)) {
4301             hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
4302             destroy_hist_field(hist_field, 0);
4303             ret = -EINVAL;
4304             goto out;
4305         }
4306
4307         key_size = hist_field->size;
4308     }
4309
4310     hist_data->fields[key_idx] = hist_field;
4311
4312     key_size = ALIGN(key_size, sizeof(u64));
4313     hist_data->fields[key_idx]->size = key_size;
4314     hist_data->fields[key_idx]->offset = key_offset;
4315
4316     hist_data->key_size += key_size;
4317
4318     if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
4319         ret = -EINVAL;
4320         goto out;
4321     }
4322
4323     hist_data->n_keys++;
4324     hist_data->n_fields++;
4325
4326     if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
4327         return -EINVAL;
4328
4329     ret = key_size;
4330  out:
4331     return ret;
4332 }
4333
4334 static int create_key_fields(struct hist_trigger_data *hist_data,
4335                  struct trace_event_file *file)
4336 {
4337     unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
4338     char *fields_str, *field_str;
4339     int ret = -EINVAL;
4340
4341     fields_str = hist_data->attrs->keys_str;
4342     if (!fields_str)
4343         goto out;
4344
4345     for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
4346         field_str = strsep(&fields_str, ",");
4347         if (!field_str)
4348             break;
4349         ret = create_key_field(hist_data, i, key_offset,
4350                        file, field_str);
4351         if (ret < 0)
4352             goto out;
4353         key_offset += ret;
4354     }
4355     if (fields_str) {
4356         ret = -EINVAL;
4357         goto out;
4358     }
4359     ret = 0;
4360  out:
4361     return ret;
4362 }
4363
4364 static int create_var_fields(struct hist_trigger_data *hist_data,
4365                  struct trace_event_file *file)
4366 {
4367     unsigned int i, j = hist_data->n_vals;
4368     int ret = 0;
4369
4370     unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
4371
4372     for (i = 0; i < n_vars; i++) {
4373         char *var_name = hist_data->attrs->var_defs.name[i];
4374         char *expr = hist_data->attrs->var_defs.expr[i];
4375
4376         ret = create_var_field(hist_data, j++, file, var_name, expr);
4377         if (ret)
4378             goto out;
4379     }
4380  out:
4381     return ret;
4382 }
4383
4384 static void free_var_defs(struct hist_trigger_data *hist_data)
4385 {
4386     unsigned int i;
4387
4388     for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
4389         kfree(hist_data->attrs->var_defs.name[i]);
4390         kfree(hist_data->attrs->var_defs.expr[i]);
4391     }
4392
4393     hist_data->attrs->var_defs.n_vars = 0;
4394 }
4395
4396 static int parse_var_defs(struct hist_trigger_data *hist_data)
4397 {
4398     struct trace_array *tr = hist_data->event_file->tr;
4399     char *s, *str, *var_name, *field_str;
4400     unsigned int i, j, n_vars = 0;
4401     int ret = 0;
4402
4403     for (i = 0; i < hist_data->attrs->n_assignments; i++) {
4404         str = hist_data->attrs->assignment_str[i];
4405         for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
4406             field_str = strsep(&str, ",");
4407             if (!field_str)
4408                 break;
4409
4410             var_name = strsep(&field_str, "=");
4411             if (!var_name || !field_str) {
4412                 hist_err(tr, HIST_ERR_MALFORMED_ASSIGNMENT,
4413                      errpos(var_name));
4414                 ret = -EINVAL;
4415                 goto free;
4416             }
4417
4418             if (n_vars == TRACING_MAP_VARS_MAX) {
4419                 hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(var_name));
4420                 ret = -EINVAL;
4421                 goto free;
4422             }
4423
4424             s = kstrdup(var_name, GFP_KERNEL);
4425             if (!s) {
4426                 ret = -ENOMEM;
4427                 goto free;
4428             }
4429             hist_data->attrs->var_defs.name[n_vars] = s;
4430
4431             s = kstrdup(field_str, GFP_KERNEL);
4432             if (!s) {
4433                 kfree(hist_data->attrs->var_defs.name[n_vars]);
4434                 hist_data->attrs->var_defs.name[n_vars] = NULL;
4435                 ret = -ENOMEM;
4436                 goto free;
4437             }
4438             hist_data->attrs->var_defs.expr[n_vars++] = s;
4439
4440             hist_data->attrs->var_defs.n_vars = n_vars;
4441         }
4442     }
4443
4444     return ret;
4445  free:
4446     free_var_defs(hist_data);
4447
4448     return ret;
4449 }
4450
4451 static int create_hist_fields(struct hist_trigger_data *hist_data,
4452                   struct trace_event_file *file)
4453 {
4454     int ret;
4455
4456     ret = parse_var_defs(hist_data);
4457     if (ret)
4458         return ret;
4459
4460     ret = create_val_fields(hist_data, file);
4461     if (ret)
4462         goto out;
4463
4464     ret = create_var_fields(hist_data, file);
4465     if (ret)
4466         goto out;
4467
4468     ret = create_key_fields(hist_data, file);
4469
4470  out:
4471     free_var_defs(hist_data);
4472
4473     return ret;
4474 }
4475
4476 static int is_descending(struct trace_array *tr, const char *str)
4477 {
4478     if (!str)
4479         return 0;
4480
4481     if (strcmp(str, "descending") == 0)
4482         return 1;
4483
4484     if (strcmp(str, "ascending") == 0)
4485         return 0;
4486
4487     hist_err(tr, HIST_ERR_INVALID_SORT_MODIFIER, errpos((char *)str));
4488
4489     return -EINVAL;
4490 }
4491
4492 static int create_sort_keys(struct hist_trigger_data *hist_data)
4493 {
4494     struct trace_array *tr = hist_data->event_file->tr;
4495     char *fields_str = hist_data->attrs->sort_key_str;
4496     struct tracing_map_sort_key *sort_key;
4497     int descending, ret = 0;
4498     unsigned int i, j, k;
4499
4500     hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
4501
4502     if (!fields_str)
4503         goto out;
4504
4505     for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
4506         struct hist_field *hist_field;
4507         char *field_str, *field_name;
4508         const char *test_name;
4509
4510         sort_key = &hist_data->sort_keys[i];
4511
4512         field_str = strsep(&fields_str, ",");
4513         if (!field_str)
4514             break;
4515
4516         if (!*field_str) {
4517             ret = -EINVAL;
4518             hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4519             break;
4520         }
4521
4522         if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
4523             hist_err(tr, HIST_ERR_TOO_MANY_SORT_FIELDS, errpos("sort="));
4524             ret = -EINVAL;
4525             break;
4526         }
4527
4528         field_name = strsep(&field_str, ".");
4529         if (!field_name || !*field_name) {
4530             ret = -EINVAL;
4531             hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4532             break;
4533         }
4534
4535         if (strcmp(field_name, "hitcount") == 0) {
4536             descending = is_descending(tr, field_str);
4537             if (descending < 0) {
4538                 ret = descending;
4539                 break;
4540             }
4541             sort_key->descending = descending;
4542             continue;
4543         }
4544
4545         for (j = 1, k = 1; j < hist_data->n_fields; j++) {
4546             unsigned int idx;
4547
4548             hist_field = hist_data->fields[j];
4549             if (hist_field->flags & HIST_FIELD_FL_VAR)
4550                 continue;
4551
4552             idx = k++;
4553
4554             test_name = hist_field_name(hist_field, 0);
4555
4556             if (strcmp(field_name, test_name) == 0) {
4557                 sort_key->field_idx = idx;
4558                 descending = is_descending(tr, field_str);
4559                 if (descending < 0) {
4560                     ret = descending;
4561                     goto out;
4562                 }
4563                 sort_key->descending = descending;
4564                 break;
4565             }
4566         }
4567         if (j == hist_data->n_fields) {
4568             ret = -EINVAL;
4569             hist_err(tr, HIST_ERR_INVALID_SORT_FIELD, errpos(field_name));
4570             break;
4571         }
4572     }
4573
4574     hist_data->n_sort_keys = i;
4575  out:
4576     return ret;
4577 }
4578
4579 static void destroy_actions(struct hist_trigger_data *hist_data)
4580 {
4581     unsigned int i;
4582
4583     for (i = 0; i < hist_data->n_actions; i++) {
4584         struct action_data *data = hist_data->actions[i];
4585
4586         if (data->handler == HANDLER_ONMATCH)
4587             onmatch_destroy(data);
4588         else if (data->handler == HANDLER_ONMAX ||
4589              data->handler == HANDLER_ONCHANGE)
4590             track_data_destroy(hist_data, data);
4591         else
4592             kfree(data);
4593     }
4594 }
4595
4596 static int parse_actions(struct hist_trigger_data *hist_data)
4597 {
4598     struct trace_array *tr = hist_data->event_file->tr;
4599     struct action_data *data;
4600     unsigned int i;
4601     int ret = 0;
4602     char *str;
4603     int len;
4604
4605     for (i = 0; i < hist_data->attrs->n_actions; i++) {
4606         str = hist_data->attrs->action_str[i];
4607
4608         if ((len = str_has_prefix(str, "onmatch("))) {
4609             char *action_str = str + len;
4610
4611             data = onmatch_parse(tr, action_str);
4612             if (IS_ERR(data)) {
4613                 ret = PTR_ERR(data);
4614                 break;
4615             }
4616         } else if ((len = str_has_prefix(str, "onmax("))) {
4617             char *action_str = str + len;
4618
4619             data = track_data_parse(hist_data, action_str,
4620                         HANDLER_ONMAX);
4621             if (IS_ERR(data)) {
4622                 ret = PTR_ERR(data);
4623                 break;
4624             }
4625         } else if ((len = str_has_prefix(str, "onchange("))) {
4626             char *action_str = str + len;
4627
4628             data = track_data_parse(hist_data, action_str,
4629                         HANDLER_ONCHANGE);
4630             if (IS_ERR(data)) {
4631                 ret = PTR_ERR(data);
4632                 break;
4633             }
4634         } else {
4635             ret = -EINVAL;
4636             break;
4637         }
4638
4639         hist_data->actions[hist_data->n_actions++] = data;
4640     }
4641
4642     return ret;
4643 }
4644
4645 static int create_actions(struct hist_trigger_data *hist_data)
4646 {
4647     struct action_data *data;
4648     unsigned int i;
4649     int ret = 0;
4650
4651     for (i = 0; i < hist_data->attrs->n_actions; i++) {
4652         data = hist_data->actions[i];
4653
4654         if (data->handler == HANDLER_ONMATCH) {
4655             ret = onmatch_create(hist_data, data);
4656             if (ret)
4657                 break;
4658         } else if (data->handler == HANDLER_ONMAX ||
4659                data->handler == HANDLER_ONCHANGE) {
4660             ret = track_data_create(hist_data, data);
4661             if (ret)
4662                 break;
4663         } else {
4664             ret = -EINVAL;
4665             break;
4666         }
4667     }
4668
4669     return ret;
4670 }
4671
4672 static void print_actions(struct seq_file *m,
4673               struct hist_trigger_data *hist_data,
4674               struct tracing_map_elt *elt)
4675 {
4676     unsigned int i;
4677
4678     for (i = 0; i < hist_data->n_actions; i++) {
4679         struct action_data *data = hist_data->actions[i];
4680
4681         if (data->action == ACTION_SNAPSHOT)
4682             continue;
4683
4684         if (data->handler == HANDLER_ONMAX ||
4685             data->handler == HANDLER_ONCHANGE)
4686             track_data_print(m, hist_data, elt, data);
4687     }
4688 }
4689
4690 static void print_action_spec(struct seq_file *m,
4691                   struct hist_trigger_data *hist_data,
4692                   struct action_data *data)
4693 {
4694     unsigned int i;
4695
4696     if (data->action == ACTION_SAVE) {
4697         for (i = 0; i < hist_data->n_save_vars; i++) {
4698             seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
4699             if (i < hist_data->n_save_vars - 1)
4700                 seq_puts(m, ",");
4701         }
4702     } else if (data->action == ACTION_TRACE) {
4703         if (data->use_trace_keyword)
4704             seq_printf(m, "%s", data->synth_event_name);
4705         for (i = 0; i < data->n_params; i++) {
4706             if (i || data->use_trace_keyword)
4707                 seq_puts(m, ",");
4708             seq_printf(m, "%s", data->params[i]);
4709         }
4710     }
4711 }
4712
4713 static void print_track_data_spec(struct seq_file *m,
4714                   struct hist_trigger_data *hist_data,
4715                   struct action_data *data)
4716 {
4717     if (data->handler == HANDLER_ONMAX)
4718         seq_puts(m, ":onmax(");
4719     else if (data->handler == HANDLER_ONCHANGE)
4720         seq_puts(m, ":onchange(");
4721     seq_printf(m, "%s", data->track_data.var_str);
4722     seq_printf(m, ").%s(", data->action_name);
4723
4724     print_action_spec(m, hist_data, data);
4725
4726     seq_puts(m, ")");
4727 }
4728
4729 static void print_onmatch_spec(struct seq_file *m,
4730                    struct hist_trigger_data *hist_data,
4731                    struct action_data *data)
4732 {
4733     seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
4734            data->match_data.event);
4735
4736     seq_printf(m, "%s(", data->action_name);
4737
4738     print_action_spec(m, hist_data, data);
4739
4740     seq_puts(m, ")");
4741 }
4742
4743 static bool actions_match(struct hist_trigger_data *hist_data,
4744               struct hist_trigger_data *hist_data_test)
4745 {
4746     unsigned int i, j;
4747
4748     if (hist_data->n_actions != hist_data_test->n_actions)
4749         return false;
4750
4751     for (i = 0; i < hist_data->n_actions; i++) {
4752         struct action_data *data = hist_data->actions[i];
4753         struct action_data *data_test = hist_data_test->actions[i];
4754         char *action_name, *action_name_test;
4755
4756         if (data->handler != data_test->handler)
4757             return false;
4758         if (data->action != data_test->action)
4759             return false;
4760
4761         if (data->n_params != data_test->n_params)
4762             return false;
4763
4764         for (j = 0; j < data->n_params; j++) {
4765             if (strcmp(data->params[j], data_test->params[j]) != 0)
4766                 return false;
4767         }
4768
4769         if (data->use_trace_keyword)
4770             action_name = data->synth_event_name;
4771         else
4772             action_name = data->action_name;
4773
4774         if (data_test->use_trace_keyword)
4775             action_name_test = data_test->synth_event_name;
4776         else
4777             action_name_test = data_test->action_name;
4778
4779         if (strcmp(action_name, action_name_test) != 0)
4780             return false;
4781
4782         if (data->handler == HANDLER_ONMATCH) {
4783             if (strcmp(data->match_data.event_system,
4784                    data_test->match_data.event_system) != 0)
4785                 return false;
4786             if (strcmp(data->match_data.event,
4787                    data_test->match_data.event) != 0)
4788                 return false;
4789         } else if (data->handler == HANDLER_ONMAX ||
4790                data->handler == HANDLER_ONCHANGE) {
4791             if (strcmp(data->track_data.var_str,
4792                    data_test->track_data.var_str) != 0)
4793                 return false;
4794         }
4795     }
4796
4797     return true;
4798 }
4799
4800
4801 static void print_actions_spec(struct seq_file *m,
4802                    struct hist_trigger_data *hist_data)
4803 {
4804     unsigned int i;
4805
4806     for (i = 0; i < hist_data->n_actions; i++) {
4807         struct action_data *data = hist_data->actions[i];
4808
4809         if (data->handler == HANDLER_ONMATCH)
4810             print_onmatch_spec(m, hist_data, data);
4811         else if (data->handler == HANDLER_ONMAX ||
4812              data->handler == HANDLER_ONCHANGE)
4813             print_track_data_spec(m, hist_data, data);
4814     }
4815 }
4816
4817 static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
4818 {
4819     unsigned int i;
4820
4821     for (i = 0; i < hist_data->n_field_var_hists; i++) {
4822         kfree(hist_data->field_var_hists[i]->cmd);
4823         kfree(hist_data->field_var_hists[i]);
4824     }
4825 }
4826
4827 static void destroy_hist_data(struct hist_trigger_data *hist_data)
4828 {
4829     if (!hist_data)
4830         return;
4831
4832     destroy_hist_trigger_attrs(hist_data->attrs);
4833     destroy_hist_fields(hist_data);
4834     tracing_map_destroy(hist_data->map);
4835
4836     destroy_actions(hist_data);
4837     destroy_field_vars(hist_data);
4838     destroy_field_var_hists(hist_data);
4839
4840     kfree(hist_data);
4841 }
4842
4843 static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
4844 {
4845     struct tracing_map *map = hist_data->map;
4846     struct ftrace_event_field *field;
4847     struct hist_field *hist_field;
4848     int i, idx = 0;
4849
4850     for_each_hist_field(i, hist_data) {
4851         hist_field = hist_data->fields[i];
4852         if (hist_field->flags & HIST_FIELD_FL_KEY) {
4853             tracing_map_cmp_fn_t cmp_fn;
4854
4855             field = hist_field->field;
4856
4857             if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
4858                 cmp_fn = tracing_map_cmp_none;
4859             else if (!field || hist_field->flags & HIST_FIELD_FL_CPU)
4860                 cmp_fn = tracing_map_cmp_num(hist_field->size,
4861                                  hist_field->is_signed);
4862             else if (is_string_field(field))
4863                 cmp_fn = tracing_map_cmp_string;
4864             else
4865                 cmp_fn = tracing_map_cmp_num(field->size,
4866                                  field->is_signed);
4867             idx = tracing_map_add_key_field(map,
4868                             hist_field->offset,
4869                             cmp_fn);
4870         } else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
4871             idx = tracing_map_add_sum_field(map);
4872
4873         if (idx < 0)
4874             return idx;
4875
4876         if (hist_field->flags & HIST_FIELD_FL_VAR) {
4877             idx = tracing_map_add_var(map);
4878             if (idx < 0)
4879                 return idx;
4880             hist_field->var.idx = idx;
4881             hist_field->var.hist_data = hist_data;
4882         }
4883     }
4884
4885     return 0;
4886 }
4887
4888 static struct hist_trigger_data *
4889 create_hist_data(unsigned int map_bits,
4890          struct hist_trigger_attrs *attrs,
4891          struct trace_event_file *file,
4892          bool remove)
4893 {
4894     const struct tracing_map_ops *map_ops = NULL;
4895     struct hist_trigger_data *hist_data;
4896     int ret = 0;
4897
4898     hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
4899     if (!hist_data)
4900         return ERR_PTR(-ENOMEM);
4901
4902     hist_data->attrs = attrs;
4903     hist_data->remove = remove;
4904     hist_data->event_file = file;
4905
4906     ret = parse_actions(hist_data);
4907     if (ret)
4908         goto free;
4909
4910     ret = create_hist_fields(hist_data, file);
4911     if (ret)
4912         goto free;
4913
4914     ret = create_sort_keys(hist_data);
4915     if (ret)
4916         goto free;
4917
4918     map_ops = &hist_trigger_elt_data_ops;
4919
4920     hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
4921                         map_ops, hist_data);
4922     if (IS_ERR(hist_data->map)) {
4923         ret = PTR_ERR(hist_data->map);
4924         hist_data->map = NULL;
4925         goto free;
4926     }
4927
4928     ret = create_tracing_map_fields(hist_data);
4929     if (ret)
4930         goto free;
4931  out:
4932     return hist_data;
4933  free:
4934     hist_data->attrs = NULL;
4935
4936     destroy_hist_data(hist_data);
4937
4938     hist_data = ERR_PTR(ret);
4939
4940     goto out;
4941 }
4942
4943 static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
4944                     struct tracing_map_elt *elt,
4945                     struct trace_buffer *buffer, void *rec,
4946                     struct ring_buffer_event *rbe,
4947                     u64 *var_ref_vals)
4948 {
4949     struct hist_elt_data *elt_data;
4950     struct hist_field *hist_field;
4951     unsigned int i, var_idx;
4952     u64 hist_val;
4953
4954     elt_data = elt->private_data;
4955     elt_data->var_ref_vals = var_ref_vals;
4956
4957     for_each_hist_val_field(i, hist_data) {
4958         hist_field = hist_data->fields[i];
4959         hist_val = hist_field->fn(hist_field, elt, buffer, rbe, rec);
4960         if (hist_field->flags & HIST_FIELD_FL_VAR) {
4961             var_idx = hist_field->var.idx;
4962
4963             if (hist_field->flags & HIST_FIELD_FL_STRING) {
4964                 unsigned int str_start, var_str_idx, idx;
4965                 char *str, *val_str;
4966                 unsigned int size;
4967
4968                 str_start = hist_data->n_field_var_str +
4969                     hist_data->n_save_var_str;
4970                 var_str_idx = hist_field->var_str_idx;
4971                 idx = str_start + var_str_idx;
4972
4973                 str = elt_data->field_var_str[idx];
4974                 val_str = (char *)(uintptr_t)hist_val;
4975
4976                 size = min(hist_field->size, STR_VAR_LEN_MAX);
4977                 strscpy(str, val_str, size);
4978
4979                 hist_val = (u64)(uintptr_t)str;
4980             }
4981             tracing_map_set_var(elt, var_idx, hist_val);
4982             continue;
4983         }
4984         tracing_map_update_sum(elt, i, hist_val);
4985     }
4986
4987     for_each_hist_key_field(i, hist_data) {
4988         hist_field = hist_data->fields[i];
4989         if (hist_field->flags & HIST_FIELD_FL_VAR) {
4990             hist_val = hist_field->fn(hist_field, elt, buffer, rbe, rec);
4991             var_idx = hist_field->var.idx;
4992             tracing_map_set_var(elt, var_idx, hist_val);
4993         }
4994     }
4995
4996     update_field_vars(hist_data, elt, buffer, rbe, rec);
4997 }
4998
4999 static inline void add_to_key(char *compound_key, void *key,
5000                   struct hist_field *key_field, void *rec)
5001 {
5002     size_t size = key_field->size;
5003
5004     if (key_field->flags & HIST_FIELD_FL_STRING) {
5005         struct ftrace_event_field *field;
5006
5007         field = key_field->field;
5008         if (field->filter_type == FILTER_DYN_STRING ||
5009             field->filter_type == FILTER_RDYN_STRING)
5010             size = *(u32 *)(rec + field->offset) >> 16;
5011         else if (field->filter_type == FILTER_STATIC_STRING)
5012             size = field->size;
5013
5014         /* ensure NULL-termination */
5015         if (size > key_field->size - 1)
5016             size = key_field->size - 1;
5017
5018         strncpy(compound_key + key_field->offset, (char *)key, size);
5019     } else
5020         memcpy(compound_key + key_field->offset, key, size);
5021 }
5022
5023 static void
5024 hist_trigger_actions(struct hist_trigger_data *hist_data,
5025              struct tracing_map_elt *elt,
5026              struct trace_buffer *buffer, void *rec,
5027              struct ring_buffer_event *rbe, void *key,
5028              u64 *var_ref_vals)
5029 {
5030     struct action_data *data;
5031     unsigned int i;
5032
5033     for (i = 0; i < hist_data->n_actions; i++) {
5034         data = hist_data->actions[i];
5035         data->fn(hist_data, elt, buffer, rec, rbe, key, data, var_ref_vals);
5036     }
5037 }
5038
5039 static void event_hist_trigger(struct event_trigger_data *data,
5040                    struct trace_buffer *buffer, void *rec,
5041                    struct ring_buffer_event *rbe)
5042 {
5043     struct hist_trigger_data *hist_data = data->private_data;
5044     bool use_compound_key = (hist_data->n_keys > 1);
5045     unsigned long entries[HIST_STACKTRACE_DEPTH];
5046     u64 var_ref_vals[TRACING_MAP_VARS_MAX];
5047     char compound_key[HIST_KEY_SIZE_MAX];
5048     struct tracing_map_elt *elt = NULL;
5049     struct hist_field *key_field;
5050     u64 field_contents;
5051     void *key = NULL;
5052     unsigned int i;
5053
5054     memset(compound_key, 0, hist_data->key_size);
5055
5056     for_each_hist_key_field(i, hist_data) {
5057         key_field = hist_data->fields[i];
5058
5059         if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5060             memset(entries, 0, HIST_STACKTRACE_SIZE);
5061             stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
5062                      HIST_STACKTRACE_SKIP);
5063             key = entries;
5064         } else {
5065             field_contents = key_field->fn(key_field, elt, buffer, rbe, rec);
5066             if (key_field->flags & HIST_FIELD_FL_STRING) {
5067                 key = (void *)(unsigned long)field_contents;
5068                 use_compound_key = true;
5069             } else
5070                 key = (void *)&field_contents;
5071         }
5072
5073         if (use_compound_key)
5074             add_to_key(compound_key, key, key_field, rec);
5075     }
5076
5077     if (use_compound_key)
5078         key = compound_key;
5079
5080     if (hist_data->n_var_refs &&
5081         !resolve_var_refs(hist_data, key, var_ref_vals, false))
5082         return;
5083
5084     elt = tracing_map_insert(hist_data->map, key);
5085     if (!elt)
5086         return;
5087
5088     hist_trigger_elt_update(hist_data, elt, buffer, rec, rbe, var_ref_vals);
5089
5090     if (resolve_var_refs(hist_data, key, var_ref_vals, true))
5091         hist_trigger_actions(hist_data, elt, buffer, rec, rbe, key, var_ref_vals);
5092 }
5093
5094 static void hist_trigger_stacktrace_print(struct seq_file *m,
5095                       unsigned long *stacktrace_entries,
5096                       unsigned int max_entries)
5097 {
5098     unsigned int spaces = 8;
5099     unsigned int i;
5100
5101     for (i = 0; i < max_entries; i++) {
5102         if (!stacktrace_entries[i])
5103             return;
5104
5105         seq_printf(m, "%*c", 1 + spaces, ' ');
5106         seq_printf(m, "%pS\n", (void*)stacktrace_entries[i]);
5107     }
5108 }
5109
5110 static void hist_trigger_print_key(struct seq_file *m,
5111                    struct hist_trigger_data *hist_data,
5112                    void *key,
5113                    struct tracing_map_elt *elt)
5114 {
5115     struct hist_field *key_field;
5116     bool multiline = false;
5117     const char *field_name;
5118     unsigned int i;
5119     u64 uval;
5120
5121     seq_puts(m, "{ ");
5122
5123     for_each_hist_key_field(i, hist_data) {
5124         key_field = hist_data->fields[i];
5125
5126         if (i > hist_data->n_vals)
5127             seq_puts(m, ", ");
5128
5129         field_name = hist_field_name(key_field, 0);
5130
5131         if (key_field->flags & HIST_FIELD_FL_HEX) {
5132             uval = *(u64 *)(key + key_field->offset);
5133             seq_printf(m, "%s: %llx", field_name, uval);
5134         } else if (key_field->flags & HIST_FIELD_FL_SYM) {
5135             uval = *(u64 *)(key + key_field->offset);
5136             seq_printf(m, "%s: [%llx] %-45ps", field_name,
5137                    uval, (void *)(uintptr_t)uval);
5138         } else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
5139             uval = *(u64 *)(key + key_field->offset);
5140             seq_printf(m, "%s: [%llx] %-55pS", field_name,
5141                    uval, (void *)(uintptr_t)uval);
5142         } else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
5143             struct hist_elt_data *elt_data = elt->private_data;
5144             char *comm;
5145
5146             if (WARN_ON_ONCE(!elt_data))
5147                 return;
5148
5149             comm = elt_data->comm;
5150
5151             uval = *(u64 *)(key + key_field->offset);
5152             seq_printf(m, "%s: %-16s[%10llu]", field_name,
5153                    comm, uval);
5154         } else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
5155             const char *syscall_name;
5156
5157             uval = *(u64 *)(key + key_field->offset);
5158             syscall_name = get_syscall_name(uval);
5159             if (!syscall_name)
5160                 syscall_name = "unknown_syscall";
5161
5162             seq_printf(m, "%s: %-30s[%3llu]", field_name,
5163                    syscall_name, uval);
5164         } else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5165             seq_puts(m, "stacktrace:\n");
5166             hist_trigger_stacktrace_print(m,
5167                               key + key_field->offset,
5168                               HIST_STACKTRACE_DEPTH);
5169             multiline = true;
5170         } else if (key_field->flags & HIST_FIELD_FL_LOG2) {
5171             seq_printf(m, "%s: ~ 2^%-2llu", field_name,
5172                    *(u64 *)(key + key_field->offset));
5173         } else if (key_field->flags & HIST_FIELD_FL_BUCKET) {
5174             unsigned long buckets = key_field->buckets;
5175             uval = *(u64 *)(key + key_field->offset);
5176             seq_printf(m, "%s: ~ %llu-%llu", field_name,
5177                    uval, uval + buckets -1);
5178         } else if (key_field->flags & HIST_FIELD_FL_STRING) {
5179             seq_printf(m, "%s: %-50s", field_name,
5180                    (char *)(key + key_field->offset));
5181         } else {
5182             uval = *(u64 *)(key + key_field->offset);
5183             seq_printf(m, "%s: %10llu", field_name, uval);
5184         }
5185     }
5186
5187     if (!multiline)
5188         seq_puts(m, " ");
5189
5190     seq_puts(m, "}");
5191 }
5192
5193 static void hist_trigger_entry_print(struct seq_file *m,
5194                      struct hist_trigger_data *hist_data,
5195                      void *key,
5196                      struct tracing_map_elt *elt)
5197 {
5198     const char *field_name;
5199     unsigned int i;
5200
5201     hist_trigger_print_key(m, hist_data, key, elt);
5202
5203     seq_printf(m, " hitcount: %10llu",
5204            tracing_map_read_sum(elt, HITCOUNT_IDX));
5205
5206     for (i = 1; i < hist_data->n_vals; i++) {
5207         field_name = hist_field_name(hist_data->fields[i], 0);
5208
5209         if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR ||
5210             hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR)
5211             continue;
5212
5213         if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
5214             seq_printf(m, "  %s: %10llx", field_name,
5215                    tracing_map_read_sum(elt, i));
5216         } else {
5217             seq_printf(m, "  %s: %10llu", field_name,
5218                    tracing_map_read_sum(elt, i));
5219         }
5220     }
5221
5222     print_actions(m, hist_data, elt);
5223
5224     seq_puts(m, "\n");
5225 }
5226
5227 static int print_entries(struct seq_file *m,
5228              struct hist_trigger_data *hist_data)
5229 {
5230     struct tracing_map_sort_entry **sort_entries = NULL;
5231     struct tracing_map *map = hist_data->map;
5232     int i, n_entries;
5233
5234     n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
5235                          hist_data->n_sort_keys,
5236                          &sort_entries);
5237     if (n_entries < 0)
5238         return n_entries;
5239
5240     for (i = 0; i < n_entries; i++)
5241         hist_trigger_entry_print(m, hist_data,
5242                      sort_entries[i]->key,
5243                      sort_entries[i]->elt);
5244
5245     tracing_map_destroy_sort_entries(sort_entries, n_entries);
5246
5247     return n_entries;
5248 }
5249
5250 static void hist_trigger_show(struct seq_file *m,
5251                   struct event_trigger_data *data, int n)
5252 {
5253     struct hist_trigger_data *hist_data;
5254     int n_entries;
5255
5256     if (n > 0)
5257         seq_puts(m, "\n\n");
5258
5259     seq_puts(m, "# event histogram\n#\n# trigger info: ");
5260     data->ops->print(m, data);
5261     seq_puts(m, "#\n\n");
5262
5263     hist_data = data->private_data;
5264     n_entries = print_entries(m, hist_data);
5265     if (n_entries < 0)
5266         n_entries = 0;
5267
5268     track_data_snapshot_print(m, hist_data);
5269
5270     seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
5271            (u64)atomic64_read(&hist_data->map->hits),
5272            n_entries, (u64)atomic64_read(&hist_data->map->drops));
5273 }
5274
5275 static int hist_show(struct seq_file *m, void *v)
5276 {
5277     struct event_trigger_data *data;
5278     struct trace_event_file *event_file;
5279     int n = 0, ret = 0;
5280
5281     mutex_lock(&event_mutex);
5282
5283     event_file = event_file_data(m->private);
5284     if (unlikely(!event_file)) {
5285         ret = -ENODEV;
5286         goto out_unlock;
5287     }
5288
5289     list_for_each_entry(data, &event_file->triggers, list) {
5290         if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5291             hist_trigger_show(m, data, n++);
5292     }
5293
5294  out_unlock:
5295     mutex_unlock(&event_mutex);
5296
5297     return ret;
5298 }
5299
5300 static int event_hist_open(struct inode *inode, struct file *file)
5301 {
5302     int ret;
5303
5304     ret = security_locked_down(LOCKDOWN_TRACEFS);
5305     if (ret)
5306         return ret;
5307
5308     return single_open(file, hist_show, file);
5309 }
5310
5311 const struct file_operations event_hist_fops = {
5312     .open = event_hist_open,
5313     .read = seq_read,
5314     .llseek = seq_lseek,
5315     .release = single_release,
5316 };
5317
5318 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
5319 static void hist_field_debug_show_flags(struct seq_file *m,
5320                     unsigned long flags)
5321 {
5322     seq_puts(m, "      flags:\n");
5323
5324     if (flags & HIST_FIELD_FL_KEY)
5325         seq_puts(m, "        HIST_FIELD_FL_KEY\n");
5326     else if (flags & HIST_FIELD_FL_HITCOUNT)
5327         seq_puts(m, "        VAL: HIST_FIELD_FL_HITCOUNT\n");
5328     else if (flags & HIST_FIELD_FL_VAR)
5329         seq_puts(m, "        HIST_FIELD_FL_VAR\n");
5330     else if (flags & HIST_FIELD_FL_VAR_REF)
5331         seq_puts(m, "        HIST_FIELD_FL_VAR_REF\n");
5332     else
5333         seq_puts(m, "        VAL: normal u64 value\n");
5334
5335     if (flags & HIST_FIELD_FL_ALIAS)
5336         seq_puts(m, "        HIST_FIELD_FL_ALIAS\n");
5337     else if (flags & HIST_FIELD_FL_CONST)
5338         seq_puts(m, "        HIST_FIELD_FL_CONST\n");
5339 }
5340
5341 static int hist_field_debug_show(struct seq_file *m,
5342                  struct hist_field *field, unsigned long flags)
5343 {
5344     if ((field->flags & flags) != flags) {
5345         seq_printf(m, "ERROR: bad flags - %lx\n", flags);
5346         return -EINVAL;
5347     }
5348
5349     hist_field_debug_show_flags(m, field->flags);
5350     if (field->field)
5351         seq_printf(m, "      ftrace_event_field name: %s\n",
5352                field->field->name);
5353
5354     if (field->flags & HIST_FIELD_FL_VAR) {
5355         seq_printf(m, "      var.name: %s\n", field->var.name);
5356         seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5357                field->var.idx);
5358     }
5359
5360     if (field->flags & HIST_FIELD_FL_CONST)
5361         seq_printf(m, "      constant: %llu\n", field->constant);
5362
5363     if (field->flags & HIST_FIELD_FL_ALIAS)
5364         seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5365                field->var_ref_idx);
5366
5367     if (field->flags & HIST_FIELD_FL_VAR_REF) {
5368         seq_printf(m, "      name: %s\n", field->name);
5369         seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5370                field->var.idx);
5371         seq_printf(m, "      var.hist_data: %p\n", field->var.hist_data);
5372         seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5373                field->var_ref_idx);
5374         if (field->system)
5375             seq_printf(m, "      system: %s\n", field->system);
5376         if (field->event_name)
5377             seq_printf(m, "      event_name: %s\n", field->event_name);
5378     }
5379
5380     seq_printf(m, "      type: %s\n", field->type);
5381     seq_printf(m, "      size: %u\n", field->size);
5382     seq_printf(m, "      is_signed: %u\n", field->is_signed);
5383
5384     return 0;
5385 }
5386
5387 static int field_var_debug_show(struct seq_file *m,
5388                 struct field_var *field_var, unsigned int i,
5389                 bool save_vars)
5390 {
5391     const char *vars_name = save_vars ? "save_vars" : "field_vars";
5392     struct hist_field *field;
5393     int ret = 0;
5394
5395     seq_printf(m, "\n    hist_data->%s[%d]:\n", vars_name, i);
5396
5397     field = field_var->var;
5398
5399     seq_printf(m, "\n      %s[%d].var:\n", vars_name, i);
5400
5401     hist_field_debug_show_flags(m, field->flags);
5402     seq_printf(m, "      var.name: %s\n", field->var.name);
5403     seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5404            field->var.idx);
5405
5406     field = field_var->val;
5407
5408     seq_printf(m, "\n      %s[%d].val:\n", vars_name, i);
5409     if (field->field)
5410         seq_printf(m, "      ftrace_event_field name: %s\n",
5411                field->field->name);
5412     else {
5413         ret = -EINVAL;
5414         goto out;
5415     }
5416
5417     seq_printf(m, "      type: %s\n", field->type);
5418     seq_printf(m, "      size: %u\n", field->size);
5419     seq_printf(m, "      is_signed: %u\n", field->is_signed);
5420 out:
5421     return ret;
5422 }
5423
5424 static int hist_action_debug_show(struct seq_file *m,
5425                   struct action_data *data, int i)
5426 {
5427     int ret = 0;
5428
5429     if (data->handler == HANDLER_ONMAX ||
5430         data->handler == HANDLER_ONCHANGE) {
5431         seq_printf(m, "\n    hist_data->actions[%d].track_data.var_ref:\n", i);
5432         ret = hist_field_debug_show(m, data->track_data.var_ref,
5433                         HIST_FIELD_FL_VAR_REF);
5434         if (ret)
5435             goto out;
5436
5437         seq_printf(m, "\n    hist_data->actions[%d].track_data.track_var:\n", i);
5438         ret = hist_field_debug_show(m, data->track_data.track_var,
5439                         HIST_FIELD_FL_VAR);
5440         if (ret)
5441             goto out;
5442     }
5443
5444     if (data->handler == HANDLER_ONMATCH) {
5445         seq_printf(m, "\n    hist_data->actions[%d].match_data.event_system: %s\n",
5446                i, data->match_data.event_system);
5447         seq_printf(m, "    hist_data->actions[%d].match_data.event: %s\n",
5448                i, data->match_data.event);
5449     }
5450 out:
5451     return ret;
5452 }
5453
5454 static int hist_actions_debug_show(struct seq_file *m,
5455                    struct hist_trigger_data *hist_data)
5456 {
5457     int i, ret = 0;
5458
5459     if (hist_data->n_actions)
5460         seq_puts(m, "\n  action tracking variables (for onmax()/onchange()/onmatch()):\n");
5461
5462     for (i = 0; i < hist_data->n_actions; i++) {
5463         struct action_data *action = hist_data->actions[i];
5464
5465         ret = hist_action_debug_show(m, action, i);
5466         if (ret)
5467             goto out;
5468     }
5469
5470     if (hist_data->n_save_vars)
5471         seq_puts(m, "\n  save action variables (save() params):\n");
5472
5473     for (i = 0; i < hist_data->n_save_vars; i++) {
5474         ret = field_var_debug_show(m, hist_data->save_vars[i], i, true);
5475         if (ret)
5476             goto out;
5477     }
5478 out:
5479     return ret;
5480 }
5481
5482 static void hist_trigger_debug_show(struct seq_file *m,
5483                     struct event_trigger_data *data, int n)
5484 {
5485     struct hist_trigger_data *hist_data;
5486     int i, ret;
5487
5488     if (n > 0)
5489         seq_puts(m, "\n\n");
5490
5491     seq_puts(m, "# event histogram\n#\n# trigger info: ");
5492     data->ops->print(m, data);
5493     seq_puts(m, "#\n\n");
5494
5495     hist_data = data->private_data;
5496
5497     seq_printf(m, "hist_data: %p\n\n", hist_data);
5498     seq_printf(m, "  n_vals: %u\n", hist_data->n_vals);
5499     seq_printf(m, "  n_keys: %u\n", hist_data->n_keys);
5500     seq_printf(m, "  n_fields: %u\n", hist_data->n_fields);
5501
5502     seq_puts(m, "\n  val fields:\n\n");
5503
5504     seq_puts(m, "    hist_data->fields[0]:\n");
5505     ret = hist_field_debug_show(m, hist_data->fields[0],
5506                     HIST_FIELD_FL_HITCOUNT);
5507     if (ret)
5508         return;
5509
5510     for (i = 1; i < hist_data->n_vals; i++) {
5511         seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
5512         ret = hist_field_debug_show(m, hist_data->fields[i], 0);
5513         if (ret)
5514             return;
5515     }
5516
5517     seq_puts(m, "\n  key fields:\n");
5518
5519     for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
5520         seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
5521         ret = hist_field_debug_show(m, hist_data->fields[i],
5522                         HIST_FIELD_FL_KEY);
5523         if (ret)
5524             return;
5525     }
5526
5527     if (hist_data->n_var_refs)
5528         seq_puts(m, "\n  variable reference fields:\n");
5529
5530     for (i = 0; i < hist_data->n_var_refs; i++) {
5531         seq_printf(m, "\n    hist_data->var_refs[%d]:\n", i);
5532         ret = hist_field_debug_show(m, hist_data->var_refs[i],
5533                         HIST_FIELD_FL_VAR_REF);
5534         if (ret)
5535             return;
5536     }
5537
5538     if (hist_data->n_field_vars)
5539         seq_puts(m, "\n  field variables:\n");
5540
5541     for (i = 0; i < hist_data->n_field_vars; i++) {
5542         ret = field_var_debug_show(m, hist_data->field_vars[i], i, false);
5543         if (ret)
5544             return;
5545     }
5546
5547     ret = hist_actions_debug_show(m, hist_data);
5548     if (ret)
5549         return;
5550 }
5551
5552 static int hist_debug_show(struct seq_file *m, void *v)
5553 {
5554     struct event_trigger_data *data;
5555     struct trace_event_file *event_file;
5556     int n = 0, ret = 0;
5557
5558     mutex_lock(&event_mutex);
5559
5560     event_file = event_file_data(m->private);
5561     if (unlikely(!event_file)) {
5562         ret = -ENODEV;
5563         goto out_unlock;
5564     }
5565
5566     list_for_each_entry(data, &event_file->triggers, list) {
5567         if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5568             hist_trigger_debug_show(m, data, n++);
5569     }
5570
5571  out_unlock:
5572     mutex_unlock(&event_mutex);
5573
5574     return ret;
5575 }
5576
5577 static int event_hist_debug_open(struct inode *inode, struct file *file)
5578 {
5579     int ret;
5580
5581     ret = security_locked_down(LOCKDOWN_TRACEFS);
5582     if (ret)
5583         return ret;
5584
5585     return single_open(file, hist_debug_show, file);
5586 }
5587
5588 const struct file_operations event_hist_debug_fops = {
5589     .open = event_hist_debug_open,
5590     .read = seq_read,
5591     .llseek = seq_lseek,
5592     .release = single_release,
5593 };
5594 #endif
5595
5596 static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
5597 {
5598     const char *field_name = hist_field_name(hist_field, 0);
5599
5600     if (hist_field->var.name)
5601         seq_printf(m, "%s=", hist_field->var.name);
5602
5603     if (hist_field->flags & HIST_FIELD_FL_CPU)
5604         seq_puts(m, "common_cpu");
5605     else if (hist_field->flags & HIST_FIELD_FL_CONST)
5606         seq_printf(m, "%llu", hist_field->constant);
5607     else if (field_name) {
5608         if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
5609             hist_field->flags & HIST_FIELD_FL_ALIAS)
5610             seq_putc(m, '$');
5611         seq_printf(m, "%s", field_name);
5612     } else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
5613         seq_puts(m, "common_timestamp");
5614
5615     if (hist_field->flags) {
5616         if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
5617             !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
5618             const char *flags = get_hist_field_flags(hist_field);
5619
5620             if (flags)
5621                 seq_printf(m, ".%s", flags);
5622         }
5623     }
5624     if (hist_field->buckets)
5625         seq_printf(m, "=%ld", hist_field->buckets);
5626 }
5627
5628 static int event_hist_trigger_print(struct seq_file *m,
5629                     struct event_trigger_data *data)
5630 {
5631     struct hist_trigger_data *hist_data = data->private_data;
5632     struct hist_field *field;
5633     bool have_var = false;
5634     unsigned int i;
5635
5636     seq_puts(m, HIST_PREFIX);
5637
5638     if (data->name)
5639         seq_printf(m, "%s:", data->name);
5640
5641     seq_puts(m, "keys=");
5642
5643     for_each_hist_key_field(i, hist_data) {
5644         field = hist_data->fields[i];
5645
5646         if (i > hist_data->n_vals)
5647             seq_puts(m, ",");
5648
5649         if (field->flags & HIST_FIELD_FL_STACKTRACE)
5650             seq_puts(m, "stacktrace");
5651         else
5652             hist_field_print(m, field);
5653     }
5654
5655     seq_puts(m, ":vals=");
5656
5657     for_each_hist_val_field(i, hist_data) {
5658         field = hist_data->fields[i];
5659         if (field->flags & HIST_FIELD_FL_VAR) {
5660             have_var = true;
5661             continue;
5662         }
5663
5664         if (i == HITCOUNT_IDX)
5665             seq_puts(m, "hitcount");
5666         else {
5667             seq_puts(m, ",");
5668             hist_field_print(m, field);
5669         }
5670     }
5671
5672     if (have_var) {
5673         unsigned int n = 0;
5674
5675         seq_puts(m, ":");
5676
5677         for_each_hist_val_field(i, hist_data) {
5678             field = hist_data->fields[i];
5679
5680             if (field->flags & HIST_FIELD_FL_VAR) {
5681                 if (n++)
5682                     seq_puts(m, ",");
5683                 hist_field_print(m, field);
5684             }
5685         }
5686     }
5687
5688     seq_puts(m, ":sort=");
5689
5690     for (i = 0; i < hist_data->n_sort_keys; i++) {
5691         struct tracing_map_sort_key *sort_key;
5692         unsigned int idx, first_key_idx;
5693
5694         /* skip VAR vals */
5695         first_key_idx = hist_data->n_vals - hist_data->n_vars;
5696
5697         sort_key = &hist_data->sort_keys[i];
5698         idx = sort_key->field_idx;
5699
5700         if (WARN_ON(idx >= HIST_FIELDS_MAX))
5701             return -EINVAL;
5702
5703         if (i > 0)
5704             seq_puts(m, ",");
5705
5706         if (idx == HITCOUNT_IDX)
5707             seq_puts(m, "hitcount");
5708         else {
5709             if (idx >= first_key_idx)
5710                 idx += hist_data->n_vars;
5711             hist_field_print(m, hist_data->fields[idx]);
5712         }
5713
5714         if (sort_key->descending)
5715             seq_puts(m, ".descending");
5716     }
5717     seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
5718     if (hist_data->enable_timestamps)
5719         seq_printf(m, ":clock=%s", hist_data->attrs->clock);
5720
5721     print_actions_spec(m, hist_data);
5722
5723     if (data->filter_str)
5724         seq_printf(m, " if %s", data->filter_str);
5725
5726     if (data->paused)
5727         seq_puts(m, " [paused]");
5728     else
5729         seq_puts(m, " [active]");
5730
5731     seq_putc(m, '\n');
5732
5733     return 0;
5734 }
5735
5736 static int event_hist_trigger_init(struct event_trigger_data *data)
5737 {
5738     struct hist_trigger_data *hist_data = data->private_data;
5739
5740     if (!data->ref && hist_data->attrs->name)
5741         save_named_trigger(hist_data->attrs->name, data);
5742
5743     data->ref++;
5744
5745     return 0;
5746 }
5747
5748 static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
5749 {
5750     struct trace_event_file *file;
5751     unsigned int i;
5752     char *cmd;
5753     int ret;
5754
5755     for (i = 0; i < hist_data->n_field_var_hists; i++) {
5756         file = hist_data->field_var_hists[i]->hist_data->event_file;
5757         cmd = hist_data->field_var_hists[i]->cmd;
5758         ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
5759                            "!hist", "hist", cmd);
5760         WARN_ON_ONCE(ret < 0);
5761     }
5762 }
5763
5764 static void event_hist_trigger_free(struct event_trigger_data *data)
5765 {
5766     struct hist_trigger_data *hist_data = data->private_data;
5767
5768     if (WARN_ON_ONCE(data->ref <= 0))
5769         return;
5770
5771     data->ref--;
5772     if (!data->ref) {
5773         if (data->name)
5774             del_named_trigger(data);
5775
5776         trigger_data_free(data);
5777
5778         remove_hist_vars(hist_data);
5779
5780         unregister_field_var_hists(hist_data);
5781
5782         destroy_hist_data(hist_data);
5783     }
5784 }
5785
5786 static struct event_trigger_ops event_hist_trigger_ops = {
5787     .trigger        = event_hist_trigger,
5788     .print          = event_hist_trigger_print,
5789     .init           = event_hist_trigger_init,
5790     .free           = event_hist_trigger_free,
5791 };
5792
5793 static int event_hist_trigger_named_init(struct event_trigger_data *data)
5794 {
5795     data->ref++;
5796
5797     save_named_trigger(data->named_data->name, data);
5798
5799     event_hist_trigger_init(data->named_data);
5800
5801     return 0;
5802 }
5803
5804 static void event_hist_trigger_named_free(struct event_trigger_data *data)
5805 {
5806     if (WARN_ON_ONCE(data->ref <= 0))
5807         return;
5808
5809     event_hist_trigger_free(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 bool existing_hist_update_only(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     bool updated = false;
5943
5944     if (!hist_data->attrs->pause && !hist_data->attrs->cont &&
5945         !hist_data->attrs->clear)
5946         goto out;
5947
5948     if (hist_data->attrs->name) {
5949         named_data = find_named_trigger(hist_data->attrs->name);
5950         if (named_data) {
5951             if (!hist_trigger_match(data, named_data, named_data,
5952                         true))
5953                 goto out;
5954         }
5955     }
5956
5957     if (hist_data->attrs->name && !named_data)
5958         goto out;
5959
5960     list_for_each_entry(test, &file->triggers, list) {
5961         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5962             if (!hist_trigger_match(data, test, named_data, false))
5963                 continue;
5964             if (hist_data->attrs->pause)
5965                 test->paused = true;
5966             else if (hist_data->attrs->cont)
5967                 test->paused = false;
5968             else if (hist_data->attrs->clear)
5969                 hist_clear(test);
5970             updated = true;
5971             goto out;
5972         }
5973     }
5974  out:
5975     return updated;
5976 }
5977
5978 static int hist_register_trigger(char *glob,
5979                  struct event_trigger_data *data,
5980                  struct trace_event_file *file)
5981 {
5982     struct hist_trigger_data *hist_data = data->private_data;
5983     struct event_trigger_data *test, *named_data = NULL;
5984     struct trace_array *tr = file->tr;
5985     int ret = 0;
5986
5987     if (hist_data->attrs->name) {
5988         named_data = find_named_trigger(hist_data->attrs->name);
5989         if (named_data) {
5990             if (!hist_trigger_match(data, named_data, named_data,
5991                         true)) {
5992                 hist_err(tr, HIST_ERR_NAMED_MISMATCH, errpos(hist_data->attrs->name));
5993                 ret = -EINVAL;
5994                 goto out;
5995             }
5996         }
5997     }
5998
5999     if (hist_data->attrs->name && !named_data)
6000         goto new;
6001
6002     lockdep_assert_held(&event_mutex);
6003
6004     list_for_each_entry(test, &file->triggers, list) {
6005         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6006             if (hist_trigger_match(data, test, named_data, false)) {
6007                 hist_err(tr, HIST_ERR_TRIGGER_EEXIST, 0);
6008                 ret = -EEXIST;
6009                 goto out;
6010             }
6011         }
6012     }
6013  new:
6014     if (hist_data->attrs->cont || hist_data->attrs->clear) {
6015         hist_err(tr, HIST_ERR_TRIGGER_ENOENT_CLEAR, 0);
6016         ret = -ENOENT;
6017         goto out;
6018     }
6019
6020     if (hist_data->attrs->pause)
6021         data->paused = true;
6022
6023     if (named_data) {
6024         data->private_data = named_data->private_data;
6025         set_named_trigger_data(data, named_data);
6026         data->ops = &event_hist_trigger_named_ops;
6027     }
6028
6029     if (data->ops->init) {
6030         ret = data->ops->init(data);
6031         if (ret < 0)
6032             goto out;
6033     }
6034
6035     if (hist_data->enable_timestamps) {
6036         char *clock = hist_data->attrs->clock;
6037
6038         ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
6039         if (ret) {
6040             hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
6041             goto out;
6042         }
6043
6044         tracing_set_filter_buffering(file->tr, true);
6045     }
6046
6047     if (named_data)
6048         destroy_hist_data(hist_data);
6049  out:
6050     return ret;
6051 }
6052
6053 static int hist_trigger_enable(struct event_trigger_data *data,
6054                    struct trace_event_file *file)
6055 {
6056     int ret = 0;
6057
6058     list_add_tail_rcu(&data->list, &file->triggers);
6059
6060     update_cond_flag(file);
6061
6062     if (trace_event_trigger_enable_disable(file, 1) < 0) {
6063         list_del_rcu(&data->list);
6064         update_cond_flag(file);
6065         ret--;
6066     }
6067
6068     return ret;
6069 }
6070
6071 static bool have_hist_trigger_match(struct event_trigger_data *data,
6072                     struct trace_event_file *file)
6073 {
6074     struct hist_trigger_data *hist_data = data->private_data;
6075     struct event_trigger_data *test, *named_data = NULL;
6076     bool match = false;
6077
6078     lockdep_assert_held(&event_mutex);
6079
6080     if (hist_data->attrs->name)
6081         named_data = find_named_trigger(hist_data->attrs->name);
6082
6083     list_for_each_entry(test, &file->triggers, list) {
6084         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6085             if (hist_trigger_match(data, test, named_data, false)) {
6086                 match = true;
6087                 break;
6088             }
6089         }
6090     }
6091
6092     return match;
6093 }
6094
6095 static bool hist_trigger_check_refs(struct event_trigger_data *data,
6096                     struct trace_event_file *file)
6097 {
6098     struct hist_trigger_data *hist_data = data->private_data;
6099     struct event_trigger_data *test, *named_data = NULL;
6100
6101     lockdep_assert_held(&event_mutex);
6102
6103     if (hist_data->attrs->name)
6104         named_data = find_named_trigger(hist_data->attrs->name);
6105
6106     list_for_each_entry(test, &file->triggers, list) {
6107         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6108             if (!hist_trigger_match(data, test, named_data, false))
6109                 continue;
6110             hist_data = test->private_data;
6111             if (check_var_refs(hist_data))
6112                 return true;
6113             break;
6114         }
6115     }
6116
6117     return false;
6118 }
6119
6120 static void hist_unregister_trigger(char *glob,
6121                     struct event_trigger_data *data,
6122                     struct trace_event_file *file)
6123 {
6124     struct event_trigger_data *test = NULL, *iter, *named_data = NULL;
6125     struct hist_trigger_data *hist_data = data->private_data;
6126
6127     lockdep_assert_held(&event_mutex);
6128
6129     if (hist_data->attrs->name)
6130         named_data = find_named_trigger(hist_data->attrs->name);
6131
6132     list_for_each_entry(iter, &file->triggers, list) {
6133         if (iter->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6134             if (!hist_trigger_match(data, iter, named_data, false))
6135                 continue;
6136             test = iter;
6137             list_del_rcu(&test->list);
6138             trace_event_trigger_enable_disable(file, 0);
6139             update_cond_flag(file);
6140             break;
6141         }
6142     }
6143
6144     if (test && test->ops->free)
6145         test->ops->free(test);
6146
6147     if (hist_data->enable_timestamps) {
6148         if (!hist_data->remove || test)
6149             tracing_set_filter_buffering(file->tr, false);
6150     }
6151 }
6152
6153 static bool hist_file_check_refs(struct trace_event_file *file)
6154 {
6155     struct hist_trigger_data *hist_data;
6156     struct event_trigger_data *test;
6157
6158     lockdep_assert_held(&event_mutex);
6159
6160     list_for_each_entry(test, &file->triggers, list) {
6161         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6162             hist_data = test->private_data;
6163             if (check_var_refs(hist_data))
6164                 return true;
6165         }
6166     }
6167
6168     return false;
6169 }
6170
6171 static void hist_unreg_all(struct trace_event_file *file)
6172 {
6173     struct event_trigger_data *test, *n;
6174     struct hist_trigger_data *hist_data;
6175     struct synth_event *se;
6176     const char *se_name;
6177
6178     lockdep_assert_held(&event_mutex);
6179
6180     if (hist_file_check_refs(file))
6181         return;
6182
6183     list_for_each_entry_safe(test, n, &file->triggers, list) {
6184         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6185             hist_data = test->private_data;
6186             list_del_rcu(&test->list);
6187             trace_event_trigger_enable_disable(file, 0);
6188
6189             se_name = trace_event_name(file->event_call);
6190             se = find_synth_event(se_name);
6191             if (se)
6192                 se->ref--;
6193
6194             update_cond_flag(file);
6195             if (hist_data->enable_timestamps)
6196                 tracing_set_filter_buffering(file->tr, false);
6197             if (test->ops->free)
6198                 test->ops->free(test);
6199         }
6200     }
6201 }
6202
6203 static int event_hist_trigger_parse(struct event_command *cmd_ops,
6204                     struct trace_event_file *file,
6205                     char *glob, char *cmd,
6206                     char *param_and_filter)
6207 {
6208     unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
6209     struct event_trigger_data *trigger_data;
6210     struct hist_trigger_attrs *attrs;
6211     struct hist_trigger_data *hist_data;
6212     char *param, *filter, *p, *start;
6213     struct synth_event *se;
6214     const char *se_name;
6215     bool remove;
6216     int ret = 0;
6217
6218     lockdep_assert_held(&event_mutex);
6219
6220     if (WARN_ON(!glob))
6221         return -EINVAL;
6222
6223     if (glob[0]) {
6224         hist_err_clear();
6225         last_cmd_set(file, param_and_filter);
6226     }
6227
6228     remove = event_trigger_check_remove(glob);
6229
6230     if (event_trigger_empty_param(param_and_filter))
6231         return -EINVAL;
6232
6233     /*
6234      * separate the trigger from the filter (k:v [if filter])
6235      * allowing for whitespace in the trigger
6236      */
6237     p = param = param_and_filter;
6238     do {
6239         p = strstr(p, "if");
6240         if (!p)
6241             break;
6242         if (p == param_and_filter)
6243             return -EINVAL;
6244         if (*(p - 1) != ' ' && *(p - 1) != '\t') {
6245             p++;
6246             continue;
6247         }
6248         if (p >= param_and_filter + strlen(param_and_filter) - (sizeof("if") - 1) - 1)
6249             return -EINVAL;
6250         if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
6251             p++;
6252             continue;
6253         }
6254         break;
6255     } while (1);
6256
6257     if (!p)
6258         filter = NULL;
6259     else {
6260         *(p - 1) = '\0';
6261         filter = strstrip(p);
6262         param = strstrip(param);
6263     }
6264
6265     /*
6266      * To simplify arithmetic expression parsing, replace occurrences of
6267      * '.sym-offset' modifier with '.symXoffset'
6268      */
6269     start = strstr(param, ".sym-offset");
6270     while (start) {
6271         *(start + 4) = 'X';
6272         start = strstr(start + 11, ".sym-offset");
6273     }
6274
6275     attrs = parse_hist_trigger_attrs(file->tr, param);
6276     if (IS_ERR(attrs))
6277         return PTR_ERR(attrs);
6278
6279     if (attrs->map_bits)
6280         hist_trigger_bits = attrs->map_bits;
6281
6282     hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
6283     if (IS_ERR(hist_data)) {
6284         destroy_hist_trigger_attrs(attrs);
6285         return PTR_ERR(hist_data);
6286     }
6287
6288     trigger_data = event_trigger_alloc(cmd_ops, cmd, param, hist_data);
6289     if (!trigger_data) {
6290         ret = -ENOMEM;
6291         goto out_free;
6292     }
6293
6294     ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
6295     if (ret < 0)
6296         goto out_free;
6297
6298     if (remove) {
6299         if (!have_hist_trigger_match(trigger_data, file))
6300             goto out_free;
6301
6302         if (hist_trigger_check_refs(trigger_data, file)) {
6303             ret = -EBUSY;
6304             goto out_free;
6305         }
6306
6307         event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
6308         se_name = trace_event_name(file->event_call);
6309         se = find_synth_event(se_name);
6310         if (se)
6311             se->ref--;
6312         ret = 0;
6313         goto out_free;
6314     }
6315
6316     if (existing_hist_update_only(glob, trigger_data, file))
6317         goto out_free;
6318
6319     ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
6320     if (ret < 0)
6321         goto out_free;
6322
6323     if (get_named_trigger_data(trigger_data))
6324         goto enable;
6325
6326     if (has_hist_vars(hist_data))
6327         save_hist_vars(hist_data);
6328
6329     ret = create_actions(hist_data);
6330     if (ret)
6331         goto out_unreg;
6332
6333     ret = tracing_map_init(hist_data->map);
6334     if (ret)
6335         goto out_unreg;
6336 enable:
6337     ret = hist_trigger_enable(trigger_data, file);
6338     if (ret)
6339         goto out_unreg;
6340
6341     se_name = trace_event_name(file->event_call);
6342     se = find_synth_event(se_name);
6343     if (se)
6344         se->ref++;
6345  out:
6346     if (ret == 0)
6347         hist_err_clear();
6348
6349     return ret;
6350  out_unreg:
6351     event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
6352  out_free:
6353     event_trigger_reset_filter(cmd_ops, trigger_data);
6354
6355     remove_hist_vars(hist_data);
6356
6357     kfree(trigger_data);
6358
6359     destroy_hist_data(hist_data);
6360     goto out;
6361 }
6362
6363 static struct event_command trigger_hist_cmd = {
6364     .name           = "hist",
6365     .trigger_type       = ETT_EVENT_HIST,
6366     .flags          = EVENT_CMD_FL_NEEDS_REC,
6367     .parse          = event_hist_trigger_parse,
6368     .reg            = hist_register_trigger,
6369     .unreg          = hist_unregister_trigger,
6370     .unreg_all      = hist_unreg_all,
6371     .get_trigger_ops    = event_hist_get_trigger_ops,
6372     .set_filter     = set_trigger_filter,
6373 };
6374
6375 __init int register_trigger_hist_cmd(void)
6376 {
6377     int ret;
6378
6379     ret = register_event_command(&trigger_hist_cmd);
6380     WARN_ON(ret < 0);
6381
6382     return ret;
6383 }
6384
6385 static void
6386 hist_enable_trigger(struct event_trigger_data *data,
6387             struct trace_buffer *buffer,  void *rec,
6388             struct ring_buffer_event *event)
6389 {
6390     struct enable_trigger_data *enable_data = data->private_data;
6391     struct event_trigger_data *test;
6392
6393     list_for_each_entry_rcu(test, &enable_data->file->triggers, list,
6394                 lockdep_is_held(&event_mutex)) {
6395         if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6396             if (enable_data->enable)
6397                 test->paused = false;
6398             else
6399                 test->paused = true;
6400         }
6401     }
6402 }
6403
6404 static void
6405 hist_enable_count_trigger(struct event_trigger_data *data,
6406               struct trace_buffer *buffer,  void *rec,
6407               struct ring_buffer_event *event)
6408 {
6409     if (!data->count)
6410         return;
6411
6412     if (data->count != -1)
6413         (data->count)--;
6414
6415     hist_enable_trigger(data, buffer, rec, event);
6416 }
6417
6418 static struct event_trigger_ops hist_enable_trigger_ops = {
6419     .trigger        = hist_enable_trigger,
6420     .print          = event_enable_trigger_print,
6421     .init           = event_trigger_init,
6422     .free           = event_enable_trigger_free,
6423 };
6424
6425 static struct event_trigger_ops hist_enable_count_trigger_ops = {
6426     .trigger        = hist_enable_count_trigger,
6427     .print          = event_enable_trigger_print,
6428     .init           = event_trigger_init,
6429     .free           = event_enable_trigger_free,
6430 };
6431
6432 static struct event_trigger_ops hist_disable_trigger_ops = {
6433     .trigger        = hist_enable_trigger,
6434     .print          = event_enable_trigger_print,
6435     .init           = event_trigger_init,
6436     .free           = event_enable_trigger_free,
6437 };
6438
6439 static struct event_trigger_ops hist_disable_count_trigger_ops = {
6440     .trigger        = hist_enable_count_trigger,
6441     .print          = event_enable_trigger_print,
6442     .init           = event_trigger_init,
6443     .free           = event_enable_trigger_free,
6444 };
6445
6446 static struct event_trigger_ops *
6447 hist_enable_get_trigger_ops(char *cmd, char *param)
6448 {
6449     struct event_trigger_ops *ops;
6450     bool enable;
6451
6452     enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
6453
6454     if (enable)
6455         ops = param ? &hist_enable_count_trigger_ops :
6456             &hist_enable_trigger_ops;
6457     else
6458         ops = param ? &hist_disable_count_trigger_ops :
6459             &hist_disable_trigger_ops;
6460
6461     return ops;
6462 }
6463
6464 static void hist_enable_unreg_all(struct trace_event_file *file)
6465 {
6466     struct event_trigger_data *test, *n;
6467
6468     list_for_each_entry_safe(test, n, &file->triggers, list) {
6469         if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
6470             list_del_rcu(&test->list);
6471             update_cond_flag(file);
6472             trace_event_trigger_enable_disable(file, 0);
6473             if (test->ops->free)
6474                 test->ops->free(test);
6475         }
6476     }
6477 }
6478
6479 static struct event_command trigger_hist_enable_cmd = {
6480     .name           = ENABLE_HIST_STR,
6481     .trigger_type       = ETT_HIST_ENABLE,
6482     .parse          = event_enable_trigger_parse,
6483     .reg            = event_enable_register_trigger,
6484     .unreg          = event_enable_unregister_trigger,
6485     .unreg_all      = hist_enable_unreg_all,
6486     .get_trigger_ops    = hist_enable_get_trigger_ops,
6487     .set_filter     = set_trigger_filter,
6488 };
6489
6490 static struct event_command trigger_hist_disable_cmd = {
6491     .name           = DISABLE_HIST_STR,
6492     .trigger_type       = ETT_HIST_ENABLE,
6493     .parse          = event_enable_trigger_parse,
6494     .reg            = event_enable_register_trigger,
6495     .unreg          = event_enable_unregister_trigger,
6496     .unreg_all      = hist_enable_unreg_all,
6497     .get_trigger_ops    = hist_enable_get_trigger_ops,
6498     .set_filter     = set_trigger_filter,
6499 };
6500
6501 static __init void unregister_trigger_hist_enable_disable_cmds(void)
6502 {
6503     unregister_event_command(&trigger_hist_enable_cmd);
6504     unregister_event_command(&trigger_hist_disable_cmd);
6505 }
6506
6507 __init int register_trigger_hist_enable_disable_cmds(void)
6508 {
6509     int ret;
6510
6511     ret = register_event_command(&trigger_hist_enable_cmd);
6512     if (WARN_ON(ret < 0))
6513         return ret;
6514     ret = register_event_command(&trigger_hist_disable_cmd);
6515     if (WARN_ON(ret < 0))
6516         unregister_trigger_hist_enable_disable_cmds();
6517
6518     return ret;
6519 }