1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * trace_events_hist - trace event hist triggers
   4 *
   5 * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/kallsyms.h>
  10#include <linux/security.h>
  11#include <linux/mutex.h>
  12#include <linux/slab.h>
  13#include <linux/stacktrace.h>
  14#include <linux/rculist.h>
  15#include <linux/tracefs.h>
  16
  17/* for gfp flag names */
  18#include <linux/trace_events.h>
  19#include <trace/events/mmflags.h>
  20
  21#include "tracing_map.h"
  22#include "trace_synth.h"
  23
  24#define ERRORS								\
  25	C(NONE,			"No error"),				\
  26	C(DUPLICATE_VAR,	"Variable already defined"),		\
  27	C(VAR_NOT_UNIQUE,	"Variable name not unique, need to use fully qualified name (subsys.event.var) for variable"), \
  28	C(TOO_MANY_VARS,	"Too many variables defined"),		\
  29	C(MALFORMED_ASSIGNMENT,	"Malformed assignment"),		\
  30	C(NAMED_MISMATCH,	"Named hist trigger doesn't match existing named trigger (includes variables)"), \
  31	C(TRIGGER_EEXIST,	"Hist trigger already exists"),		\
  32	C(TRIGGER_ENOENT_CLEAR,	"Can't clear or continue a nonexistent hist trigger"), \
  33	C(SET_CLOCK_FAIL,	"Couldn't set trace_clock"),		\
  34	C(BAD_FIELD_MODIFIER,	"Invalid field modifier"),		\
  35	C(TOO_MANY_SUBEXPR,	"Too many subexpressions (3 max)"),	\
  36	C(TIMESTAMP_MISMATCH,	"Timestamp units in expression don't match"), \
  37	C(TOO_MANY_FIELD_VARS,	"Too many field variables defined"),	\
  38	C(EVENT_FILE_NOT_FOUND,	"Event file not found"),		\
  39	C(HIST_NOT_FOUND,	"Matching event histogram not found"),	\
  40	C(HIST_CREATE_FAIL,	"Couldn't create histogram for field"),	\
  41	C(SYNTH_VAR_NOT_FOUND,	"Couldn't find synthetic variable"),	\
  42	C(SYNTH_EVENT_NOT_FOUND,"Couldn't find synthetic event"),	\
  43	C(SYNTH_TYPE_MISMATCH,	"Param type doesn't match synthetic event field type"), \
  44	C(SYNTH_COUNT_MISMATCH,	"Param count doesn't match synthetic event field count"), \
  45	C(FIELD_VAR_PARSE_FAIL,	"Couldn't parse field variable"),	\
  46	C(VAR_CREATE_FIND_FAIL,	"Couldn't create or find variable"),	\
  47	C(ONX_NOT_VAR,		"For onmax(x) or onchange(x), x must be a variable"), \
  48	C(ONX_VAR_NOT_FOUND,	"Couldn't find onmax or onchange variable"), \
  49	C(ONX_VAR_CREATE_FAIL,	"Couldn't create onmax or onchange variable"), \
  50	C(FIELD_VAR_CREATE_FAIL,"Couldn't create field variable"),	\
  51	C(TOO_MANY_PARAMS,	"Too many action params"),		\
  52	C(PARAM_NOT_FOUND,	"Couldn't find param"),			\
  53	C(INVALID_PARAM,	"Invalid action param"),		\
  54	C(ACTION_NOT_FOUND,	"No action found"),			\
  55	C(NO_SAVE_PARAMS,	"No params found for save()"),		\
  56	C(TOO_MANY_SAVE_ACTIONS,"Can't have more than one save() action per hist"), \
  57	C(ACTION_MISMATCH,	"Handler doesn't support action"),	\
  58	C(NO_CLOSING_PAREN,	"No closing paren found"),		\
  59	C(SUBSYS_NOT_FOUND,	"Missing subsystem"),			\
  60	C(INVALID_SUBSYS_EVENT,	"Invalid subsystem or event name"),	\
  61	C(INVALID_REF_KEY,	"Using variable references in keys not supported"), \
  62	C(VAR_NOT_FOUND,	"Couldn't find variable"),		\
  63	C(FIELD_NOT_FOUND,	"Couldn't find field"),			\
  64	C(EMPTY_ASSIGNMENT,	"Empty assignment"),			\
  65	C(INVALID_SORT_MODIFIER,"Invalid sort modifier"),		\
  66	C(EMPTY_SORT_FIELD,	"Empty sort field"),			\
  67	C(TOO_MANY_SORT_FIELDS,	"Too many sort fields (Max = 2)"),	\
  68	C(INVALID_SORT_FIELD,	"Sort field must be a key or a val"),	\
  69	C(INVALID_STR_OPERAND,	"String type can not be an operand in expression"), \
  70	C(EXPECT_NUMBER,	"Expecting numeric literal"),		\
  71	C(UNARY_MINUS_SUBEXPR,	"Unary minus not supported in sub-expressions"), \
  72	C(DIVISION_BY_ZERO,	"Division by zero"),			\
  73	C(NEED_NOHC_VAL,	"Non-hitcount value is required for 'nohitcount'"),
  74
  75#undef C
  76#define C(a, b)		HIST_ERR_##a
  77
  78enum { ERRORS };
  79
  80#undef C
  81#define C(a, b)		b
  82
  83static const char *err_text[] = { ERRORS };
  84
  85struct hist_field;
  86
  87typedef u64 (*hist_field_fn_t) (struct hist_field *field,
  88				struct tracing_map_elt *elt,
  89				struct trace_buffer *buffer,
  90				struct ring_buffer_event *rbe,
  91				void *event);
  92
  93#define HIST_FIELD_OPERANDS_MAX	2
  94#define HIST_FIELDS_MAX		(TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
  95#define HIST_ACTIONS_MAX	8
  96#define HIST_CONST_DIGITS_MAX	21
  97#define HIST_DIV_SHIFT		20  /* For optimizing division by constants */
  98
  99enum field_op_id {
 100	FIELD_OP_NONE,
 101	FIELD_OP_PLUS,
 102	FIELD_OP_MINUS,
 103	FIELD_OP_UNARY_MINUS,
 104	FIELD_OP_DIV,
 105	FIELD_OP_MULT,
 106};
 107
 108enum hist_field_fn {
 109	HIST_FIELD_FN_NOP,
 110	HIST_FIELD_FN_VAR_REF,
 111	HIST_FIELD_FN_COUNTER,
 112	HIST_FIELD_FN_CONST,
 113	HIST_FIELD_FN_LOG2,
 114	HIST_FIELD_FN_BUCKET,
 115	HIST_FIELD_FN_TIMESTAMP,
 116	HIST_FIELD_FN_CPU,
 117	HIST_FIELD_FN_STRING,
 118	HIST_FIELD_FN_DYNSTRING,
 119	HIST_FIELD_FN_RELDYNSTRING,
 120	HIST_FIELD_FN_PSTRING,
 121	HIST_FIELD_FN_S64,
 122	HIST_FIELD_FN_U64,
 123	HIST_FIELD_FN_S32,
 124	HIST_FIELD_FN_U32,
 125	HIST_FIELD_FN_S16,
 126	HIST_FIELD_FN_U16,
 127	HIST_FIELD_FN_S8,
 128	HIST_FIELD_FN_U8,
 129	HIST_FIELD_FN_UMINUS,
 130	HIST_FIELD_FN_MINUS,
 131	HIST_FIELD_FN_PLUS,
 132	HIST_FIELD_FN_DIV,
 133	HIST_FIELD_FN_MULT,
 134	HIST_FIELD_FN_DIV_POWER2,
 135	HIST_FIELD_FN_DIV_NOT_POWER2,
 136	HIST_FIELD_FN_DIV_MULT_SHIFT,
 137	HIST_FIELD_FN_EXECNAME,
 138	HIST_FIELD_FN_STACK,
 139};
 140
 141/*
 142 * A hist_var (histogram variable) contains variable information for
 143 * hist_fields having the HIST_FIELD_FL_VAR or HIST_FIELD_FL_VAR_REF
 144 * flag set.  A hist_var has a variable name e.g. ts0, and is
 145 * associated with a given histogram trigger, as specified by
 146 * hist_data.  The hist_var idx is the unique index assigned to the
 147 * variable by the hist trigger's tracing_map.  The idx is what is
 148 * used to set a variable's value and, by a variable reference, to
 149 * retrieve it.
 150 */
 151struct hist_var {
 152	char				*name;
 153	struct hist_trigger_data	*hist_data;
 154	unsigned int			idx;
 155};
 156
 157struct hist_field {
 158	struct ftrace_event_field	*field;
 159	unsigned long			flags;
 160	unsigned long			buckets;
 161	const char			*type;
 162	struct hist_field		*operands[HIST_FIELD_OPERANDS_MAX];
 163	struct hist_trigger_data	*hist_data;
 164	enum hist_field_fn		fn_num;
 165	unsigned int			ref;
 166	unsigned int			size;
 167	unsigned int			offset;
 168	unsigned int                    is_signed;
 169
 170	/*
 171	 * Variable fields contain variable-specific info in var.
 172	 */
 173	struct hist_var			var;
 174	enum field_op_id		operator;
 175	char				*system;
 176	char				*event_name;
 177
 178	/*
 179	 * The name field is used for EXPR and VAR_REF fields.  VAR
 180	 * fields contain the variable name in var.name.
 181	 */
 182	char				*name;
 183
 184	/*
 185	 * When a histogram trigger is hit, if it has any references
 186	 * to variables, the values of those variables are collected
 187	 * into a var_ref_vals array by resolve_var_refs().  The
 188	 * current value of each variable is read from the tracing_map
 189	 * using the hist field's hist_var.idx and entered into the
 190	 * var_ref_idx entry i.e. var_ref_vals[var_ref_idx].
 191	 */
 192	unsigned int			var_ref_idx;
 193	bool                            read_once;
 194
 195	unsigned int			var_str_idx;
 196
 197	/* Numeric literals are represented as u64 */
 198	u64				constant;
 199	/* Used to optimize division by constants */
 200	u64				div_multiplier;
 201};
 202
 203static u64 hist_fn_call(struct hist_field *hist_field,
 204			struct tracing_map_elt *elt,
 205			struct trace_buffer *buffer,
 206			struct ring_buffer_event *rbe,
 207			void *event);
 208
 209static u64 hist_field_const(struct hist_field *field,
 210			   struct tracing_map_elt *elt,
 211			   struct trace_buffer *buffer,
 212			   struct ring_buffer_event *rbe,
 213			   void *event)
 214{
 215	return field->constant;
 216}
 217
 218static u64 hist_field_counter(struct hist_field *field,
 219			      struct tracing_map_elt *elt,
 220			      struct trace_buffer *buffer,
 221			      struct ring_buffer_event *rbe,
 222			      void *event)
 223{
 224	return 1;
 225}
 226
 227static u64 hist_field_string(struct hist_field *hist_field,
 228			     struct tracing_map_elt *elt,
 229			     struct trace_buffer *buffer,
 230			     struct ring_buffer_event *rbe,
 231			     void *event)
 232{
 233	char *addr = (char *)(event + hist_field->field->offset);
 234
 235	return (u64)(unsigned long)addr;
 236}
 237
 238static u64 hist_field_dynstring(struct hist_field *hist_field,
 239				struct tracing_map_elt *elt,
 240				struct trace_buffer *buffer,
 241				struct ring_buffer_event *rbe,
 242				void *event)
 243{
 244	u32 str_item = *(u32 *)(event + hist_field->field->offset);
 245	int str_loc = str_item & 0xffff;
 246	char *addr = (char *)(event + str_loc);
 247
 248	return (u64)(unsigned long)addr;
 249}
 250
 251static u64 hist_field_reldynstring(struct hist_field *hist_field,
 252				   struct tracing_map_elt *elt,
 253				   struct trace_buffer *buffer,
 254				   struct ring_buffer_event *rbe,
 255				   void *event)
 256{
 257	u32 *item = event + hist_field->field->offset;
 258	u32 str_item = *item;
 259	int str_loc = str_item & 0xffff;
 260	char *addr = (char *)&item[1] + str_loc;
 261
 262	return (u64)(unsigned long)addr;
 263}
 264
 265static u64 hist_field_pstring(struct hist_field *hist_field,
 266			      struct tracing_map_elt *elt,
 267			      struct trace_buffer *buffer,
 268			      struct ring_buffer_event *rbe,
 269			      void *event)
 270{
 271	char **addr = (char **)(event + hist_field->field->offset);
 272
 273	return (u64)(unsigned long)*addr;
 274}
 275
 276static u64 hist_field_log2(struct hist_field *hist_field,
 277			   struct tracing_map_elt *elt,
 278			   struct trace_buffer *buffer,
 279			   struct ring_buffer_event *rbe,
 280			   void *event)
 281{
 282	struct hist_field *operand = hist_field->operands[0];
 283
 284	u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
 285
 286	return (u64) ilog2(roundup_pow_of_two(val));
 287}
 288
 289static u64 hist_field_bucket(struct hist_field *hist_field,
 290			     struct tracing_map_elt *elt,
 291			     struct trace_buffer *buffer,
 292			     struct ring_buffer_event *rbe,
 293			     void *event)
 294{
 295	struct hist_field *operand = hist_field->operands[0];
 296	unsigned long buckets = hist_field->buckets;
 297
 298	u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
 299
 300	if (WARN_ON_ONCE(!buckets))
 301		return val;
 302
 303	if (val >= LONG_MAX)
 304		val = div64_ul(val, buckets);
 305	else
 306		val = (u64)((unsigned long)val / buckets);
 307	return val * buckets;
 308}
 309
 310static u64 hist_field_plus(struct hist_field *hist_field,
 311			   struct tracing_map_elt *elt,
 312			   struct trace_buffer *buffer,
 313			   struct ring_buffer_event *rbe,
 314			   void *event)
 315{
 316	struct hist_field *operand1 = hist_field->operands[0];
 317	struct hist_field *operand2 = hist_field->operands[1];
 318
 319	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 320	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
 321
 322	return val1 + val2;
 323}
 324
 325static u64 hist_field_minus(struct hist_field *hist_field,
 326			    struct tracing_map_elt *elt,
 327			    struct trace_buffer *buffer,
 328			    struct ring_buffer_event *rbe,
 329			    void *event)
 330{
 331	struct hist_field *operand1 = hist_field->operands[0];
 332	struct hist_field *operand2 = hist_field->operands[1];
 333
 334	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 335	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
 336
 337	return val1 - val2;
 338}
 339
 340static u64 hist_field_div(struct hist_field *hist_field,
 341			   struct tracing_map_elt *elt,
 342			   struct trace_buffer *buffer,
 343			   struct ring_buffer_event *rbe,
 344			   void *event)
 345{
 346	struct hist_field *operand1 = hist_field->operands[0];
 347	struct hist_field *operand2 = hist_field->operands[1];
 348
 349	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 350	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
 351
 352	/* Return -1 for the undefined case */
 353	if (!val2)
 354		return -1;
 355
 356	/* Use shift if the divisor is a power of 2 */
 357	if (!(val2 & (val2 - 1)))
 358		return val1 >> __ffs64(val2);
 359
 360	return div64_u64(val1, val2);
 361}
 362
 363static u64 div_by_power_of_two(struct hist_field *hist_field,
 364				struct tracing_map_elt *elt,
 365				struct trace_buffer *buffer,
 366				struct ring_buffer_event *rbe,
 367				void *event)
 368{
 369	struct hist_field *operand1 = hist_field->operands[0];
 370	struct hist_field *operand2 = hist_field->operands[1];
 371
 372	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 373
 374	return val1 >> __ffs64(operand2->constant);
 375}
 376
 377static u64 div_by_not_power_of_two(struct hist_field *hist_field,
 378				struct tracing_map_elt *elt,
 379				struct trace_buffer *buffer,
 380				struct ring_buffer_event *rbe,
 381				void *event)
 382{
 383	struct hist_field *operand1 = hist_field->operands[0];
 384	struct hist_field *operand2 = hist_field->operands[1];
 385
 386	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 387
 388	return div64_u64(val1, operand2->constant);
 389}
 390
 391static u64 div_by_mult_and_shift(struct hist_field *hist_field,
 392				struct tracing_map_elt *elt,
 393				struct trace_buffer *buffer,
 394				struct ring_buffer_event *rbe,
 395				void *event)
 396{
 397	struct hist_field *operand1 = hist_field->operands[0];
 398	struct hist_field *operand2 = hist_field->operands[1];
 399
 400	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 401
 402	/*
 403	 * If the divisor is a constant, do a multiplication and shift instead.
 404	 *
 405	 * Choose Z = some power of 2. If Y <= Z, then:
 406	 *     X / Y = (X * (Z / Y)) / Z
 407	 *
 408	 * (Z / Y) is a constant (mult) which is calculated at parse time, so:
 409	 *     X / Y = (X * mult) / Z
 410	 *
 411	 * The division by Z can be replaced by a shift since Z is a power of 2:
 412	 *     X / Y = (X * mult) >> HIST_DIV_SHIFT
 413	 *
 414	 * As long, as X < Z the results will not be off by more than 1.
 415	 */
 416	if (val1 < (1 << HIST_DIV_SHIFT)) {
 417		u64 mult = operand2->div_multiplier;
 418
 419		return (val1 * mult + ((1 << HIST_DIV_SHIFT) - 1)) >> HIST_DIV_SHIFT;
 420	}
 421
 422	return div64_u64(val1, operand2->constant);
 423}
 424
 425static u64 hist_field_mult(struct hist_field *hist_field,
 426			   struct tracing_map_elt *elt,
 427			   struct trace_buffer *buffer,
 428			   struct ring_buffer_event *rbe,
 429			   void *event)
 430{
 431	struct hist_field *operand1 = hist_field->operands[0];
 432	struct hist_field *operand2 = hist_field->operands[1];
 433
 434	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
 435	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
 436
 437	return val1 * val2;
 438}
 439
 440static u64 hist_field_unary_minus(struct hist_field *hist_field,
 441				  struct tracing_map_elt *elt,
 442				  struct trace_buffer *buffer,
 443				  struct ring_buffer_event *rbe,
 444				  void *event)
 445{
 446	struct hist_field *operand = hist_field->operands[0];
 447
 448	s64 sval = (s64)hist_fn_call(operand, elt, buffer, rbe, event);
 449	u64 val = (u64)-sval;
 450
 451	return val;
 452}
 453
 454#define DEFINE_HIST_FIELD_FN(type)					\
 455	static u64 hist_field_##type(struct hist_field *hist_field,	\
 456				     struct tracing_map_elt *elt,	\
 457				     struct trace_buffer *buffer,	\
 458				     struct ring_buffer_event *rbe,	\
 459				     void *event)			\
 460{									\
 461	type *addr = (type *)(event + hist_field->field->offset);	\
 462									\
 463	return (u64)(unsigned long)*addr;				\
 464}
 465
 466DEFINE_HIST_FIELD_FN(s64);
 467DEFINE_HIST_FIELD_FN(u64);
 468DEFINE_HIST_FIELD_FN(s32);
 469DEFINE_HIST_FIELD_FN(u32);
 470DEFINE_HIST_FIELD_FN(s16);
 471DEFINE_HIST_FIELD_FN(u16);
 472DEFINE_HIST_FIELD_FN(s8);
 473DEFINE_HIST_FIELD_FN(u8);
 474
 475#define for_each_hist_field(i, hist_data)	\
 476	for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
 477
 478#define for_each_hist_val_field(i, hist_data)	\
 479	for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
 480
 481#define for_each_hist_key_field(i, hist_data)	\
 482	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
 483
 484#define HITCOUNT_IDX		0
 485#define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
 486
 487enum hist_field_flags {
 488	HIST_FIELD_FL_HITCOUNT		= 1 << 0,
 489	HIST_FIELD_FL_KEY		= 1 << 1,
 490	HIST_FIELD_FL_STRING		= 1 << 2,
 491	HIST_FIELD_FL_HEX		= 1 << 3,
 492	HIST_FIELD_FL_SYM		= 1 << 4,
 493	HIST_FIELD_FL_SYM_OFFSET	= 1 << 5,
 494	HIST_FIELD_FL_EXECNAME		= 1 << 6,
 495	HIST_FIELD_FL_SYSCALL		= 1 << 7,
 496	HIST_FIELD_FL_STACKTRACE	= 1 << 8,
 497	HIST_FIELD_FL_LOG2		= 1 << 9,
 498	HIST_FIELD_FL_TIMESTAMP		= 1 << 10,
 499	HIST_FIELD_FL_TIMESTAMP_USECS	= 1 << 11,
 500	HIST_FIELD_FL_VAR		= 1 << 12,
 501	HIST_FIELD_FL_EXPR		= 1 << 13,
 502	HIST_FIELD_FL_VAR_REF		= 1 << 14,
 503	HIST_FIELD_FL_CPU		= 1 << 15,
 504	HIST_FIELD_FL_ALIAS		= 1 << 16,
 505	HIST_FIELD_FL_BUCKET		= 1 << 17,
 506	HIST_FIELD_FL_CONST		= 1 << 18,
 507	HIST_FIELD_FL_PERCENT		= 1 << 19,
 508	HIST_FIELD_FL_GRAPH		= 1 << 20,
 509};
 510
 511struct var_defs {
 512	unsigned int	n_vars;
 513	char		*name[TRACING_MAP_VARS_MAX];
 514	char		*expr[TRACING_MAP_VARS_MAX];
 515};
 516
 517struct hist_trigger_attrs {
 518	char		*keys_str;
 519	char		*vals_str;
 520	char		*sort_key_str;
 521	char		*name;
 522	char		*clock;
 523	bool		pause;
 524	bool		cont;
 525	bool		clear;
 526	bool		ts_in_usecs;
 527	bool		no_hitcount;
 528	unsigned int	map_bits;
 529
 530	char		*assignment_str[TRACING_MAP_VARS_MAX];
 531	unsigned int	n_assignments;
 532
 533	char		*action_str[HIST_ACTIONS_MAX];
 534	unsigned int	n_actions;
 535
 536	struct var_defs	var_defs;
 537};
 538
 539struct field_var {
 540	struct hist_field	*var;
 541	struct hist_field	*val;
 542};
 543
 544struct field_var_hist {
 545	struct hist_trigger_data	*hist_data;
 546	char				*cmd;
 547};
 548
 549struct hist_trigger_data {
 550	struct hist_field               *fields[HIST_FIELDS_MAX];
 551	unsigned int			n_vals;
 552	unsigned int			n_keys;
 553	unsigned int			n_fields;
 554	unsigned int			n_vars;
 555	unsigned int			n_var_str;
 556	unsigned int			key_size;
 557	struct tracing_map_sort_key	sort_keys[TRACING_MAP_SORT_KEYS_MAX];
 558	unsigned int			n_sort_keys;
 559	struct trace_event_file		*event_file;
 560	struct hist_trigger_attrs	*attrs;
 561	struct tracing_map		*map;
 562	bool				enable_timestamps;
 563	bool				remove;
 564	struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
 565	unsigned int			n_var_refs;
 566
 567	struct action_data		*actions[HIST_ACTIONS_MAX];
 568	unsigned int			n_actions;
 569
 570	struct field_var		*field_vars[SYNTH_FIELDS_MAX];
 571	unsigned int			n_field_vars;
 572	unsigned int			n_field_var_str;
 573	struct field_var_hist		*field_var_hists[SYNTH_FIELDS_MAX];
 574	unsigned int			n_field_var_hists;
 575
 576	struct field_var		*save_vars[SYNTH_FIELDS_MAX];
 577	unsigned int			n_save_vars;
 578	unsigned int			n_save_var_str;
 579};
 580
 581struct action_data;
 582
 583typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
 584			     struct tracing_map_elt *elt,
 585			     struct trace_buffer *buffer, void *rec,
 586			     struct ring_buffer_event *rbe, void *key,
 587			     struct action_data *data, u64 *var_ref_vals);
 588
 589typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
 590
 591enum handler_id {
 592	HANDLER_ONMATCH = 1,
 593	HANDLER_ONMAX,
 594	HANDLER_ONCHANGE,
 595};
 596
 597enum action_id {
 598	ACTION_SAVE = 1,
 599	ACTION_TRACE,
 600	ACTION_SNAPSHOT,
 601};
 602
 603struct action_data {
 604	enum handler_id		handler;
 605	enum action_id		action;
 606	char			*action_name;
 607	action_fn_t		fn;
 608
 609	unsigned int		n_params;
 610	char			*params[SYNTH_FIELDS_MAX];
 611
 612	/*
 613	 * When a histogram trigger is hit, the values of any
 614	 * references to variables, including variables being passed
 615	 * as parameters to synthetic events, are collected into a
 616	 * var_ref_vals array.  This var_ref_idx array is an array of
 617	 * indices into the var_ref_vals array, one for each synthetic
 618	 * event param, and is passed to the synthetic event
 619	 * invocation.
 620	 */
 621	unsigned int		var_ref_idx[SYNTH_FIELDS_MAX];
 622	struct synth_event	*synth_event;
 623	bool			use_trace_keyword;
 624	char			*synth_event_name;
 625
 626	union {
 627		struct {
 628			char			*event;
 629			char			*event_system;
 630		} match_data;
 631
 632		struct {
 633			/*
 634			 * var_str contains the $-unstripped variable
 635			 * name referenced by var_ref, and used when
 636			 * printing the action.  Because var_ref
 637			 * creation is deferred to create_actions(),
 638			 * we need a per-action way to save it until
 639			 * then, thus var_str.
 640			 */
 641			char			*var_str;
 642
 643			/*
 644			 * var_ref refers to the variable being
 645			 * tracked e.g onmax($var).
 646			 */
 647			struct hist_field	*var_ref;
 648
 649			/*
 650			 * track_var contains the 'invisible' tracking
 651			 * variable created to keep the current
 652			 * e.g. max value.
 653			 */
 654			struct hist_field	*track_var;
 655
 656			check_track_val_fn_t	check_val;
 657			action_fn_t		save_data;
 658		} track_data;
 659	};
 660};
 661
 662struct track_data {
 663	u64				track_val;
 664	bool				updated;
 665
 666	unsigned int			key_len;
 667	void				*key;
 668	struct tracing_map_elt		elt;
 669
 670	struct action_data		*action_data;
 671	struct hist_trigger_data	*hist_data;
 672};
 673
 674struct hist_elt_data {
 675	char *comm;
 676	u64 *var_ref_vals;
 677	char **field_var_str;
 678	int n_field_var_str;
 679};
 680
 681struct snapshot_context {
 682	struct tracing_map_elt	*elt;
 683	void			*key;
 684};
 685
 686/*
 687 * Returns the specific division function to use if the divisor
 688 * is constant. This avoids extra branches when the trigger is hit.
 689 */
 690static enum hist_field_fn hist_field_get_div_fn(struct hist_field *divisor)
 691{
 692	u64 div = divisor->constant;
 693
 694	if (!(div & (div - 1)))
 695		return HIST_FIELD_FN_DIV_POWER2;
 696
 697	/* If the divisor is too large, do a regular division */
 698	if (div > (1 << HIST_DIV_SHIFT))
 699		return HIST_FIELD_FN_DIV_NOT_POWER2;
 700
 701	divisor->div_multiplier = div64_u64((u64)(1 << HIST_DIV_SHIFT), div);
 702	return HIST_FIELD_FN_DIV_MULT_SHIFT;
 703}
 704
 705static void track_data_free(struct track_data *track_data)
 706{
 707	struct hist_elt_data *elt_data;
 708
 709	if (!track_data)
 710		return;
 711
 712	kfree(track_data->key);
 713
 714	elt_data = track_data->elt.private_data;
 715	if (elt_data) {
 716		kfree(elt_data->comm);
 717		kfree(elt_data);
 718	}
 719
 720	kfree(track_data);
 721}
 722
 723static struct track_data *track_data_alloc(unsigned int key_len,
 724					   struct action_data *action_data,
 725					   struct hist_trigger_data *hist_data)
 726{
 727	struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
 728	struct hist_elt_data *elt_data;
 729
 730	if (!data)
 731		return ERR_PTR(-ENOMEM);
 732
 733	data->key = kzalloc(key_len, GFP_KERNEL);
 734	if (!data->key) {
 735		track_data_free(data);
 736		return ERR_PTR(-ENOMEM);
 737	}
 738
 739	data->key_len = key_len;
 740	data->action_data = action_data;
 741	data->hist_data = hist_data;
 742
 743	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
 744	if (!elt_data) {
 745		track_data_free(data);
 746		return ERR_PTR(-ENOMEM);
 747	}
 748
 749	data->elt.private_data = elt_data;
 750
 751	elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
 752	if (!elt_data->comm) {
 753		track_data_free(data);
 754		return ERR_PTR(-ENOMEM);
 755	}
 756
 757	return data;
 758}
 759
 760#define HIST_PREFIX "hist:"
 761
 762static char *last_cmd;
 763static char last_cmd_loc[MAX_FILTER_STR_VAL];
 764
 765static int errpos(char *str)
 766{
 767	if (!str || !last_cmd)
 768		return 0;
 769
 770	return err_pos(last_cmd, str);
 771}
 772
 773static void last_cmd_set(struct trace_event_file *file, char *str)
 774{
 775	const char *system = NULL, *name = NULL;
 776	struct trace_event_call *call;
 777
 778	if (!str)
 779		return;
 780
 781	kfree(last_cmd);
 782
 783	last_cmd = kasprintf(GFP_KERNEL, HIST_PREFIX "%s", str);
 784	if (!last_cmd)
 785		return;
 786
 787	if (file) {
 788		call = file->event_call;
 789		system = call->class->system;
 790		if (system) {
 791			name = trace_event_name(call);
 792			if (!name)
 793				system = NULL;
 794		}
 795	}
 796
 797	if (system)
 798		snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name);
 799}
 800
 801static void hist_err(struct trace_array *tr, u8 err_type, u16 err_pos)
 802{
 803	if (!last_cmd)
 804		return;
 805
 806	tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
 807			err_type, err_pos);
 808}
 809
 810static void hist_err_clear(void)
 811{
 812	if (last_cmd)
 813		last_cmd[0] = '\0';
 814	last_cmd_loc[0] = '\0';
 815}
 816
 817typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
 818				    unsigned int *var_ref_idx);
 819
 820static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
 821			       unsigned int *var_ref_idx)
 822{
 823	struct tracepoint *tp = event->tp;
 824
 825	if (unlikely(static_key_enabled(&tp->key))) {
 826		struct tracepoint_func *probe_func_ptr;
 827		synth_probe_func_t probe_func;
 828		void *__data;
 829
 830		if (!(cpu_online(raw_smp_processor_id())))
 831			return;
 832
 833		probe_func_ptr = rcu_dereference_sched((tp)->funcs);
 834		if (probe_func_ptr) {
 835			do {
 836				probe_func = probe_func_ptr->func;
 837				__data = probe_func_ptr->data;
 838				probe_func(__data, var_ref_vals, var_ref_idx);
 839			} while ((++probe_func_ptr)->func);
 840		}
 841	}
 842}
 843
 844static void action_trace(struct hist_trigger_data *hist_data,
 845			 struct tracing_map_elt *elt,
 846			 struct trace_buffer *buffer, void *rec,
 847			 struct ring_buffer_event *rbe, void *key,
 848			 struct action_data *data, u64 *var_ref_vals)
 849{
 850	struct synth_event *event = data->synth_event;
 851
 852	trace_synth(event, var_ref_vals, data->var_ref_idx);
 853}
 854
 855struct hist_var_data {
 856	struct list_head list;
 857	struct hist_trigger_data *hist_data;
 858};
 859
 860static u64 hist_field_timestamp(struct hist_field *hist_field,
 861				struct tracing_map_elt *elt,
 862				struct trace_buffer *buffer,
 863				struct ring_buffer_event *rbe,
 864				void *event)
 865{
 866	struct hist_trigger_data *hist_data = hist_field->hist_data;
 867	struct trace_array *tr = hist_data->event_file->tr;
 868
 869	u64 ts = ring_buffer_event_time_stamp(buffer, rbe);
 870
 871	if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
 872		ts = ns2usecs(ts);
 873
 874	return ts;
 875}
 876
 877static u64 hist_field_cpu(struct hist_field *hist_field,
 878			  struct tracing_map_elt *elt,
 879			  struct trace_buffer *buffer,
 880			  struct ring_buffer_event *rbe,
 881			  void *event)
 882{
 883	int cpu = smp_processor_id();
 884
 885	return cpu;
 886}
 887
 888/**
 889 * check_field_for_var_ref - Check if a VAR_REF field references a variable
 890 * @hist_field: The VAR_REF field to check
 891 * @var_data: The hist trigger that owns the variable
 892 * @var_idx: The trigger variable identifier
 893 *
 894 * Check the given VAR_REF field to see whether or not it references
 895 * the given variable associated with the given trigger.
 896 *
 897 * Return: The VAR_REF field if it does reference the variable, NULL if not
 898 */
 899static struct hist_field *
 900check_field_for_var_ref(struct hist_field *hist_field,
 901			struct hist_trigger_data *var_data,
 902			unsigned int var_idx)
 903{
 904	WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));
 905
 906	if (hist_field && hist_field->var.idx == var_idx &&
 907	    hist_field->var.hist_data == var_data)
 908		return hist_field;
 909
 910	return NULL;
 911}
 912
 913/**
 914 * find_var_ref - Check if a trigger has a reference to a trigger variable
 915 * @hist_data: The hist trigger that might have a reference to the variable
 916 * @var_data: The hist trigger that owns the variable
 917 * @var_idx: The trigger variable identifier
 918 *
 919 * Check the list of var_refs[] on the first hist trigger to see
 920 * whether any of them are references to the variable on the second
 921 * trigger.
 922 *
 923 * Return: The VAR_REF field referencing the variable if so, NULL if not
 924 */
 925static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
 926				       struct hist_trigger_data *var_data,
 927				       unsigned int var_idx)
 928{
 929	struct hist_field *hist_field;
 930	unsigned int i;
 931
 932	for (i = 0; i < hist_data->n_var_refs; i++) {
 933		hist_field = hist_data->var_refs[i];
 934		if (check_field_for_var_ref(hist_field, var_data, var_idx))
 935			return hist_field;
 936	}
 937
 938	return NULL;
 939}
 940
 941/**
 942 * find_any_var_ref - Check if there is a reference to a given trigger variable
 943 * @hist_data: The hist trigger
 944 * @var_idx: The trigger variable identifier
 945 *
 946 * Check to see whether the given variable is currently referenced by
 947 * any other trigger.
 948 *
 949 * The trigger the variable is defined on is explicitly excluded - the
 950 * assumption being that a self-reference doesn't prevent a trigger
 951 * from being removed.
 952 *
 953 * Return: The VAR_REF field referencing the variable if so, NULL if not
 954 */
 955static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
 956					   unsigned int var_idx)
 957{
 958	struct trace_array *tr = hist_data->event_file->tr;
 959	struct hist_field *found = NULL;
 960	struct hist_var_data *var_data;
 961
 962	list_for_each_entry(var_data, &tr->hist_vars, list) {
 963		if (var_data->hist_data == hist_data)
 964			continue;
 965		found = find_var_ref(var_data->hist_data, hist_data, var_idx);
 966		if (found)
 967			break;
 968	}
 969
 970	return found;
 971}
 972
 973/**
 974 * check_var_refs - Check if there is a reference to any of trigger's variables
 975 * @hist_data: The hist trigger
 976 *
 977 * A trigger can define one or more variables.  If any one of them is
 978 * currently referenced by any other trigger, this function will
 979 * determine that.
 980 *
 981 * Typically used to determine whether or not a trigger can be removed
 982 * - if there are any references to a trigger's variables, it cannot.
 983 *
 984 * Return: True if there is a reference to any of trigger's variables
 985 */
 986static bool check_var_refs(struct hist_trigger_data *hist_data)
 987{
 988	struct hist_field *field;
 989	bool found = false;
 990	int i;
 991
 992	for_each_hist_field(i, hist_data) {
 993		field = hist_data->fields[i];
 994		if (field && field->flags & HIST_FIELD_FL_VAR) {
 995			if (find_any_var_ref(hist_data, field->var.idx)) {
 996				found = true;
 997				break;
 998			}
 999		}
1000	}
1001
1002	return found;
1003}
1004
1005static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
1006{
1007	struct trace_array *tr = hist_data->event_file->tr;
1008	struct hist_var_data *var_data, *found = NULL;
1009
1010	list_for_each_entry(var_data, &tr->hist_vars, list) {
1011		if (var_data->hist_data == hist_data) {
1012			found = var_data;
1013			break;
1014		}
1015	}
1016
1017	return found;
1018}
1019
1020static bool field_has_hist_vars(struct hist_field *hist_field,
1021				unsigned int level)
1022{
1023	int i;
1024
1025	if (level > 3)
1026		return false;
1027
1028	if (!hist_field)
1029		return false;
1030
1031	if (hist_field->flags & HIST_FIELD_FL_VAR ||
1032	    hist_field->flags & HIST_FIELD_FL_VAR_REF)
1033		return true;
1034
1035	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
1036		struct hist_field *operand;
1037
1038		operand = hist_field->operands[i];
1039		if (field_has_hist_vars(operand, level + 1))
1040			return true;
1041	}
1042
1043	return false;
1044}
1045
1046static bool has_hist_vars(struct hist_trigger_data *hist_data)
1047{
1048	struct hist_field *hist_field;
1049	int i;
1050
1051	for_each_hist_field(i, hist_data) {
1052		hist_field = hist_data->fields[i];
1053		if (field_has_hist_vars(hist_field, 0))
1054			return true;
1055	}
1056
1057	return false;
1058}
1059
1060static int save_hist_vars(struct hist_trigger_data *hist_data)
1061{
1062	struct trace_array *tr = hist_data->event_file->tr;
1063	struct hist_var_data *var_data;
1064
1065	var_data = find_hist_vars(hist_data);
1066	if (var_data)
1067		return 0;
1068
1069	if (tracing_check_open_get_tr(tr))
1070		return -ENODEV;
1071
1072	var_data = kzalloc(sizeof(*var_data), GFP_KERNEL);
1073	if (!var_data) {
1074		trace_array_put(tr);
1075		return -ENOMEM;
1076	}
1077
1078	var_data->hist_data = hist_data;
1079	list_add(&var_data->list, &tr->hist_vars);
1080
1081	return 0;
1082}
1083
1084static void remove_hist_vars(struct hist_trigger_data *hist_data)
1085{
1086	struct trace_array *tr = hist_data->event_file->tr;
1087	struct hist_var_data *var_data;
1088
1089	var_data = find_hist_vars(hist_data);
1090	if (!var_data)
1091		return;
1092
1093	if (WARN_ON(check_var_refs(hist_data)))
1094		return;
1095
1096	list_del(&var_data->list);
1097
1098	kfree(var_data);
1099
1100	trace_array_put(tr);
1101}
1102
1103static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
1104					 const char *var_name)
1105{
1106	struct hist_field *hist_field, *found = NULL;
1107	int i;
1108
1109	for_each_hist_field(i, hist_data) {
1110		hist_field = hist_data->fields[i];
1111		if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
1112		    strcmp(hist_field->var.name, var_name) == 0) {
1113			found = hist_field;
1114			break;
1115		}
1116	}
1117
1118	return found;
1119}
1120
1121static struct hist_field *find_var(struct hist_trigger_data *hist_data,
1122				   struct trace_event_file *file,
1123				   const char *var_name)
1124{
1125	struct hist_trigger_data *test_data;
1126	struct event_trigger_data *test;
1127	struct hist_field *hist_field;
1128
1129	lockdep_assert_held(&event_mutex);
1130
1131	hist_field = find_var_field(hist_data, var_name);
1132	if (hist_field)
1133		return hist_field;
1134
1135	list_for_each_entry(test, &file->triggers, list) {
1136		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1137			test_data = test->private_data;
1138			hist_field = find_var_field(test_data, var_name);
1139			if (hist_field)
1140				return hist_field;
1141		}
1142	}
1143
1144	return NULL;
1145}
1146
1147static struct trace_event_file *find_var_file(struct trace_array *tr,
1148					      char *system,
1149					      char *event_name,
1150					      char *var_name)
1151{
1152	struct hist_trigger_data *var_hist_data;
1153	struct hist_var_data *var_data;
1154	struct trace_event_file *file, *found = NULL;
1155
1156	if (system)
1157		return find_event_file(tr, system, event_name);
1158
1159	list_for_each_entry(var_data, &tr->hist_vars, list) {
1160		var_hist_data = var_data->hist_data;
1161		file = var_hist_data->event_file;
1162		if (file == found)
1163			continue;
1164
1165		if (find_var_field(var_hist_data, var_name)) {
1166			if (found) {
1167				hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE, errpos(var_name));
1168				return NULL;
1169			}
1170
1171			found = file;
1172		}
1173	}
1174
1175	return found;
1176}
1177
1178static struct hist_field *find_file_var(struct trace_event_file *file,
1179					const char *var_name)
1180{
1181	struct hist_trigger_data *test_data;
1182	struct event_trigger_data *test;
1183	struct hist_field *hist_field;
1184
1185	lockdep_assert_held(&event_mutex);
1186
1187	list_for_each_entry(test, &file->triggers, list) {
1188		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1189			test_data = test->private_data;
1190			hist_field = find_var_field(test_data, var_name);
1191			if (hist_field)
1192				return hist_field;
1193		}
1194	}
1195
1196	return NULL;
1197}
1198
1199static struct hist_field *
1200find_match_var(struct hist_trigger_data *hist_data, char *var_name)
1201{
1202	struct trace_array *tr = hist_data->event_file->tr;
1203	struct hist_field *hist_field, *found = NULL;
1204	struct trace_event_file *file;
1205	unsigned int i;
1206
1207	for (i = 0; i < hist_data->n_actions; i++) {
1208		struct action_data *data = hist_data->actions[i];
1209
1210		if (data->handler == HANDLER_ONMATCH) {
1211			char *system = data->match_data.event_system;
1212			char *event_name = data->match_data.event;
1213
1214			file = find_var_file(tr, system, event_name, var_name);
1215			if (!file)
1216				continue;
1217			hist_field = find_file_var(file, var_name);
1218			if (hist_field) {
1219				if (found) {
1220					hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE,
1221						 errpos(var_name));
1222					return ERR_PTR(-EINVAL);
1223				}
1224
1225				found = hist_field;
1226			}
1227		}
1228	}
1229	return found;
1230}
1231
1232static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
1233					 char *system,
1234					 char *event_name,
1235					 char *var_name)
1236{
1237	struct trace_array *tr = hist_data->event_file->tr;
1238	struct hist_field *hist_field = NULL;
1239	struct trace_event_file *file;
1240
1241	if (!system || !event_name) {
1242		hist_field = find_match_var(hist_data, var_name);
1243		if (IS_ERR(hist_field))
1244			return NULL;
1245		if (hist_field)
1246			return hist_field;
1247	}
1248
1249	file = find_var_file(tr, system, event_name, var_name);
1250	if (!file)
1251		return NULL;
1252
1253	hist_field = find_file_var(file, var_name);
1254
1255	return hist_field;
1256}
1257
1258static u64 hist_field_var_ref(struct hist_field *hist_field,
1259			      struct tracing_map_elt *elt,
1260			      struct trace_buffer *buffer,
1261			      struct ring_buffer_event *rbe,
1262			      void *event)
1263{
1264	struct hist_elt_data *elt_data;
1265	u64 var_val = 0;
1266
1267	if (WARN_ON_ONCE(!elt))
1268		return var_val;
1269
1270	elt_data = elt->private_data;
1271	var_val = elt_data->var_ref_vals[hist_field->var_ref_idx];
1272
1273	return var_val;
1274}
1275
1276static bool resolve_var_refs(struct hist_trigger_data *hist_data, void *key,
1277			     u64 *var_ref_vals, bool self)
1278{
1279	struct hist_trigger_data *var_data;
1280	struct tracing_map_elt *var_elt;
1281	struct hist_field *hist_field;
1282	unsigned int i, var_idx;
1283	bool resolved = true;
1284	u64 var_val = 0;
1285
1286	for (i = 0; i < hist_data->n_var_refs; i++) {
1287		hist_field = hist_data->var_refs[i];
1288		var_idx = hist_field->var.idx;
1289		var_data = hist_field->var.hist_data;
1290
1291		if (var_data == NULL) {
1292			resolved = false;
1293			break;
1294		}
1295
1296		if ((self && var_data != hist_data) ||
1297		    (!self && var_data == hist_data))
1298			continue;
1299
1300		var_elt = tracing_map_lookup(var_data->map, key);
1301		if (!var_elt) {
1302			resolved = false;
1303			break;
1304		}
1305
1306		if (!tracing_map_var_set(var_elt, var_idx)) {
1307			resolved = false;
1308			break;
1309		}
1310
1311		if (self || !hist_field->read_once)
1312			var_val = tracing_map_read_var(var_elt, var_idx);
1313		else
1314			var_val = tracing_map_read_var_once(var_elt, var_idx);
1315
1316		var_ref_vals[i] = var_val;
1317	}
1318
1319	return resolved;
1320}
1321
1322static const char *hist_field_name(struct hist_field *field,
1323				   unsigned int level)
1324{
1325	const char *field_name = "";
1326
1327	if (WARN_ON_ONCE(!field))
1328		return field_name;
1329
1330	if (level > 1)
1331		return field_name;
1332
1333	if (field->field)
1334		field_name = field->field->name;
1335	else if (field->flags & HIST_FIELD_FL_LOG2 ||
1336		 field->flags & HIST_FIELD_FL_ALIAS ||
1337		 field->flags & HIST_FIELD_FL_BUCKET)
1338		field_name = hist_field_name(field->operands[0], ++level);
1339	else if (field->flags & HIST_FIELD_FL_CPU)
1340		field_name = "common_cpu";
1341	else if (field->flags & HIST_FIELD_FL_EXPR ||
1342		 field->flags & HIST_FIELD_FL_VAR_REF) {
1343		if (field->system) {
1344			static char full_name[MAX_FILTER_STR_VAL];
1345
1346			strcat(full_name, field->system);
1347			strcat(full_name, ".");
1348			strcat(full_name, field->event_name);
1349			strcat(full_name, ".");
1350			strcat(full_name, field->name);
1351			field_name = full_name;
1352		} else
1353			field_name = field->name;
1354	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
1355		field_name = "common_timestamp";
1356	else if (field->flags & HIST_FIELD_FL_STACKTRACE) {
1357		field_name = "common_stacktrace";
1358	} else if (field->flags & HIST_FIELD_FL_HITCOUNT)
1359		field_name = "hitcount";
1360
1361	if (field_name == NULL)
1362		field_name = "";
1363
1364	return field_name;
1365}
1366
1367static enum hist_field_fn select_value_fn(int field_size, int field_is_signed)
1368{
1369	switch (field_size) {
1370	case 8:
1371		if (field_is_signed)
1372			return HIST_FIELD_FN_S64;
1373		else
1374			return HIST_FIELD_FN_U64;
1375	case 4:
1376		if (field_is_signed)
1377			return HIST_FIELD_FN_S32;
1378		else
1379			return HIST_FIELD_FN_U32;
1380	case 2:
1381		if (field_is_signed)
1382			return HIST_FIELD_FN_S16;
1383		else
1384			return HIST_FIELD_FN_U16;
1385	case 1:
1386		if (field_is_signed)
1387			return HIST_FIELD_FN_S8;
1388		else
1389			return HIST_FIELD_FN_U8;
1390	}
1391
1392	return HIST_FIELD_FN_NOP;
1393}
1394
1395static int parse_map_size(char *str)
1396{
1397	unsigned long size, map_bits;
1398	int ret;
1399
1400	ret = kstrtoul(str, 0, &size);
1401	if (ret)
1402		goto out;
1403
1404	map_bits = ilog2(roundup_pow_of_two(size));
1405	if (map_bits < TRACING_MAP_BITS_MIN ||
1406	    map_bits > TRACING_MAP_BITS_MAX)
1407		ret = -EINVAL;
1408	else
1409		ret = map_bits;
1410 out:
1411	return ret;
1412}
1413
1414static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
1415{
1416	unsigned int i;
1417
1418	if (!attrs)
1419		return;
1420
1421	for (i = 0; i < attrs->n_assignments; i++)
1422		kfree(attrs->assignment_str[i]);
1423
1424	for (i = 0; i < attrs->n_actions; i++)
1425		kfree(attrs->action_str[i]);
1426
1427	kfree(attrs->name);
1428	kfree(attrs->sort_key_str);
1429	kfree(attrs->keys_str);
1430	kfree(attrs->vals_str);
1431	kfree(attrs->clock);
1432	kfree(attrs);
1433}
1434
1435static int parse_action(char *str, struct hist_trigger_attrs *attrs)
1436{
1437	int ret = -EINVAL;
1438
1439	if (attrs->n_actions >= HIST_ACTIONS_MAX)
1440		return ret;
1441
1442	if ((str_has_prefix(str, "onmatch(")) ||
1443	    (str_has_prefix(str, "onmax(")) ||
1444	    (str_has_prefix(str, "onchange("))) {
1445		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
1446		if (!attrs->action_str[attrs->n_actions]) {
1447			ret = -ENOMEM;
1448			return ret;
1449		}
1450		attrs->n_actions++;
1451		ret = 0;
1452	}
1453	return ret;
1454}
1455
1456static int parse_assignment(struct trace_array *tr,
1457			    char *str, struct hist_trigger_attrs *attrs)
1458{
1459	int len, ret = 0;
1460
1461	if ((len = str_has_prefix(str, "key=")) ||
1462	    (len = str_has_prefix(str, "keys="))) {
1463		attrs->keys_str = kstrdup(str + len, GFP_KERNEL);
1464		if (!attrs->keys_str) {
1465			ret = -ENOMEM;
1466			goto out;
1467		}
1468	} else if ((len = str_has_prefix(str, "val=")) ||
1469		   (len = str_has_prefix(str, "vals=")) ||
1470		   (len = str_has_prefix(str, "values="))) {
1471		attrs->vals_str = kstrdup(str + len, GFP_KERNEL);
1472		if (!attrs->vals_str) {
1473			ret = -ENOMEM;
1474			goto out;
1475		}
1476	} else if ((len = str_has_prefix(str, "sort="))) {
1477		attrs->sort_key_str = kstrdup(str + len, GFP_KERNEL);
1478		if (!attrs->sort_key_str) {
1479			ret = -ENOMEM;
1480			goto out;
1481		}
1482	} else if (str_has_prefix(str, "name=")) {
1483		attrs->name = kstrdup(str, GFP_KERNEL);
1484		if (!attrs->name) {
1485			ret = -ENOMEM;
1486			goto out;
1487		}
1488	} else if ((len = str_has_prefix(str, "clock="))) {
1489		str += len;
1490
1491		str = strstrip(str);
1492		attrs->clock = kstrdup(str, GFP_KERNEL);
1493		if (!attrs->clock) {
1494			ret = -ENOMEM;
1495			goto out;
1496		}
1497	} else if ((len = str_has_prefix(str, "size="))) {
1498		int map_bits = parse_map_size(str + len);
1499
1500		if (map_bits < 0) {
1501			ret = map_bits;
1502			goto out;
1503		}
1504		attrs->map_bits = map_bits;
1505	} else {
1506		char *assignment;
1507
1508		if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
1509			hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(str));
1510			ret = -EINVAL;
1511			goto out;
1512		}
1513
1514		assignment = kstrdup(str, GFP_KERNEL);
1515		if (!assignment) {
1516			ret = -ENOMEM;
1517			goto out;
1518		}
1519
1520		attrs->assignment_str[attrs->n_assignments++] = assignment;
1521	}
1522 out:
1523	return ret;
1524}
1525
1526static struct hist_trigger_attrs *
1527parse_hist_trigger_attrs(struct trace_array *tr, char *trigger_str)
1528{
1529	struct hist_trigger_attrs *attrs;
1530	int ret = 0;
1531
1532	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
1533	if (!attrs)
1534		return ERR_PTR(-ENOMEM);
1535
1536	while (trigger_str) {
1537		char *str = strsep(&trigger_str, ":");
1538		char *rhs;
1539
1540		rhs = strchr(str, '=');
1541		if (rhs) {
1542			if (!strlen(++rhs)) {
1543				ret = -EINVAL;
1544				hist_err(tr, HIST_ERR_EMPTY_ASSIGNMENT, errpos(str));
1545				goto free;
1546			}
1547			ret = parse_assignment(tr, str, attrs);
1548			if (ret)
1549				goto free;
1550		} else if (strcmp(str, "nohitcount") == 0 ||
1551			   strcmp(str, "NOHC") == 0)
1552			attrs->no_hitcount = true;
1553		else if (strcmp(str, "pause") == 0)
1554			attrs->pause = true;
1555		else if ((strcmp(str, "cont") == 0) ||
1556			 (strcmp(str, "continue") == 0))
1557			attrs->cont = true;
1558		else if (strcmp(str, "clear") == 0)
1559			attrs->clear = true;
1560		else {
1561			ret = parse_action(str, attrs);
1562			if (ret)
1563				goto free;
1564		}
1565	}
1566
1567	if (!attrs->keys_str) {
1568		ret = -EINVAL;
1569		goto free;
1570	}
1571
1572	if (!attrs->clock) {
1573		attrs->clock = kstrdup("global", GFP_KERNEL);
1574		if (!attrs->clock) {
1575			ret = -ENOMEM;
1576			goto free;
1577		}
1578	}
1579
1580	return attrs;
1581 free:
1582	destroy_hist_trigger_attrs(attrs);
1583
1584	return ERR_PTR(ret);
1585}
1586
1587static inline void save_comm(char *comm, struct task_struct *task)
1588{
1589	if (!task->pid) {
1590		strcpy(comm, "<idle>");
1591		return;
1592	}
1593
1594	if (WARN_ON_ONCE(task->pid < 0)) {
1595		strcpy(comm, "<XXX>");
1596		return;
1597	}
1598
1599	strscpy(comm, task->comm, TASK_COMM_LEN);
1600}
1601
1602static void hist_elt_data_free(struct hist_elt_data *elt_data)
1603{
1604	unsigned int i;
1605
1606	for (i = 0; i < elt_data->n_field_var_str; i++)
1607		kfree(elt_data->field_var_str[i]);
1608
1609	kfree(elt_data->field_var_str);
1610
1611	kfree(elt_data->comm);
1612	kfree(elt_data);
1613}
1614
1615static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
1616{
1617	struct hist_elt_data *elt_data = elt->private_data;
1618
1619	hist_elt_data_free(elt_data);
1620}
1621
1622static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
1623{
1624	struct hist_trigger_data *hist_data = elt->map->private_data;
1625	unsigned int size = TASK_COMM_LEN;
1626	struct hist_elt_data *elt_data;
1627	struct hist_field *hist_field;
1628	unsigned int i, n_str;
1629
1630	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
1631	if (!elt_data)
1632		return -ENOMEM;
1633
1634	for_each_hist_field(i, hist_data) {
1635		hist_field = hist_data->fields[i];
1636
1637		if (hist_field->flags & HIST_FIELD_FL_EXECNAME) {
1638			elt_data->comm = kzalloc(size, GFP_KERNEL);
1639			if (!elt_data->comm) {
1640				kfree(elt_data);
1641				return -ENOMEM;
1642			}
1643			break;
1644		}
1645	}
1646
1647	n_str = hist_data->n_field_var_str + hist_data->n_save_var_str +
1648		hist_data->n_var_str;
1649	if (n_str > SYNTH_FIELDS_MAX) {
1650		hist_elt_data_free(elt_data);
1651		return -EINVAL;
1652	}
1653
1654	BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1));
1655
1656	size = STR_VAR_LEN_MAX;
1657
1658	elt_data->field_var_str = kcalloc(n_str, sizeof(char *), GFP_KERNEL);
1659	if (!elt_data->field_var_str) {
1660		hist_elt_data_free(elt_data);
1661		return -EINVAL;
1662	}
1663	elt_data->n_field_var_str = n_str;
1664
1665	for (i = 0; i < n_str; i++) {
1666		elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
1667		if (!elt_data->field_var_str[i]) {
1668			hist_elt_data_free(elt_data);
1669			return -ENOMEM;
1670		}
1671	}
1672
1673	elt->private_data = elt_data;
1674
1675	return 0;
1676}
1677
1678static void hist_trigger_elt_data_init(struct tracing_map_elt *elt)
1679{
1680	struct hist_elt_data *elt_data = elt->private_data;
1681
1682	if (elt_data->comm)
1683		save_comm(elt_data->comm, current);
1684}
1685
1686static const struct tracing_map_ops hist_trigger_elt_data_ops = {
1687	.elt_alloc	= hist_trigger_elt_data_alloc,
1688	.elt_free	= hist_trigger_elt_data_free,
1689	.elt_init	= hist_trigger_elt_data_init,
1690};
1691
1692static const char *get_hist_field_flags(struct hist_field *hist_field)
1693{
1694	const char *flags_str = NULL;
1695
1696	if (hist_field->flags & HIST_FIELD_FL_HEX)
1697		flags_str = "hex";
1698	else if (hist_field->flags & HIST_FIELD_FL_SYM)
1699		flags_str = "sym";
1700	else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
1701		flags_str = "sym-offset";
1702	else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
1703		flags_str = "execname";
1704	else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
1705		flags_str = "syscall";
1706	else if (hist_field->flags & HIST_FIELD_FL_LOG2)
1707		flags_str = "log2";
1708	else if (hist_field->flags & HIST_FIELD_FL_BUCKET)
1709		flags_str = "buckets";
1710	else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
1711		flags_str = "usecs";
1712	else if (hist_field->flags & HIST_FIELD_FL_PERCENT)
1713		flags_str = "percent";
1714	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
1715		flags_str = "graph";
1716	else if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
1717		flags_str = "stacktrace";
1718
1719	return flags_str;
1720}
1721
1722static void expr_field_str(struct hist_field *field, char *expr)
1723{
1724	if (field->flags & HIST_FIELD_FL_VAR_REF)
1725		strcat(expr, "$");
1726	else if (field->flags & HIST_FIELD_FL_CONST) {
1727		char str[HIST_CONST_DIGITS_MAX];
1728
1729		snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant);
1730		strcat(expr, str);
1731	}
1732
1733	strcat(expr, hist_field_name(field, 0));
1734
1735	if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) {
1736		const char *flags_str = get_hist_field_flags(field);
1737
1738		if (flags_str) {
1739			strcat(expr, ".");
1740			strcat(expr, flags_str);
1741		}
1742	}
1743}
1744
1745static char *expr_str(struct hist_field *field, unsigned int level)
1746{
1747	char *expr;
1748
1749	if (level > 1)
1750		return NULL;
1751
1752	expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
1753	if (!expr)
1754		return NULL;
1755
1756	if (!field->operands[0]) {
1757		expr_field_str(field, expr);
1758		return expr;
1759	}
1760
1761	if (field->operator == FIELD_OP_UNARY_MINUS) {
1762		char *subexpr;
1763
1764		strcat(expr, "-(");
1765		subexpr = expr_str(field->operands[0], ++level);
1766		if (!subexpr) {
1767			kfree(expr);
1768			return NULL;
1769		}
1770		strcat(expr, subexpr);
1771		strcat(expr, ")");
1772
1773		kfree(subexpr);
1774
1775		return expr;
1776	}
1777
1778	expr_field_str(field->operands[0], expr);
1779
1780	switch (field->operator) {
1781	case FIELD_OP_MINUS:
1782		strcat(expr, "-");
1783		break;
1784	case FIELD_OP_PLUS:
1785		strcat(expr, "+");
1786		break;
1787	case FIELD_OP_DIV:
1788		strcat(expr, "/");
1789		break;
1790	case FIELD_OP_MULT:
1791		strcat(expr, "*");
1792		break;
1793	default:
1794		kfree(expr);
1795		return NULL;
1796	}
1797
1798	expr_field_str(field->operands[1], expr);
1799
1800	return expr;
1801}
1802
1803/*
1804 * If field_op != FIELD_OP_NONE, *sep points to the root operator
1805 * of the expression tree to be evaluated.
1806 */
1807static int contains_operator(char *str, char **sep)
1808{
1809	enum field_op_id field_op = FIELD_OP_NONE;
1810	char *minus_op, *plus_op, *div_op, *mult_op;
1811
1812
1813	/*
1814	 * Report the last occurrence of the operators first, so that the
1815	 * expression is evaluated left to right. This is important since
1816	 * subtraction and division are not associative.
1817	 *
1818	 *	e.g
1819	 *		64/8/4/2 is 1, i.e 64/8/4/2 = ((64/8)/4)/2
1820	 *		14-7-5-2 is 0, i.e 14-7-5-2 = ((14-7)-5)-2
1821	 */
1822
1823	/*
1824	 * First, find lower precedence addition and subtraction
1825	 * since the expression will be evaluated recursively.
1826	 */
1827	minus_op = strrchr(str, '-');
1828	if (minus_op) {
1829		/*
1830		 * Unary minus is not supported in sub-expressions. If
1831		 * present, it is always the next root operator.
1832		 */
1833		if (minus_op == str) {
1834			field_op = FIELD_OP_UNARY_MINUS;
1835			goto out;
1836		}
1837
1838		field_op = FIELD_OP_MINUS;
1839	}
1840
1841	plus_op = strrchr(str, '+');
1842	if (plus_op || minus_op) {
1843		/*
1844		 * For operators of the same precedence use to rightmost as the
1845		 * root, so that the expression is evaluated left to right.
1846		 */
1847		if (plus_op > minus_op)
1848			field_op = FIELD_OP_PLUS;
1849		goto out;
1850	}
1851
1852	/*
1853	 * Multiplication and division have higher precedence than addition and
1854	 * subtraction.
1855	 */
1856	div_op = strrchr(str, '/');
1857	if (div_op)
1858		field_op = FIELD_OP_DIV;
1859
1860	mult_op = strrchr(str, '*');
1861	/*
1862	 * For operators of the same precedence use to rightmost as the
1863	 * root, so that the expression is evaluated left to right.
1864	 */
1865	if (mult_op > div_op)
1866		field_op = FIELD_OP_MULT;
1867
1868out:
1869	if (sep) {
1870		switch (field_op) {
1871		case FIELD_OP_UNARY_MINUS:
1872		case FIELD_OP_MINUS:
1873			*sep = minus_op;
1874			break;
1875		case FIELD_OP_PLUS:
1876			*sep = plus_op;
1877			break;
1878		case FIELD_OP_DIV:
1879			*sep = div_op;
1880			break;
1881		case FIELD_OP_MULT:
1882			*sep = mult_op;
1883			break;
1884		case FIELD_OP_NONE:
1885		default:
1886			*sep = NULL;
1887			break;
1888		}
1889	}
1890
1891	return field_op;
1892}
1893
1894static void get_hist_field(struct hist_field *hist_field)
1895{
1896	hist_field->ref++;
1897}
1898
1899static void __destroy_hist_field(struct hist_field *hist_field)
1900{
1901	if (--hist_field->ref > 1)
1902		return;
1903
1904	kfree(hist_field->var.name);
1905	kfree(hist_field->name);
1906
1907	/* Can likely be a const */
1908	kfree_const(hist_field->type);
1909
1910	kfree(hist_field->system);
1911	kfree(hist_field->event_name);
1912
1913	kfree(hist_field);
1914}
1915
1916static void destroy_hist_field(struct hist_field *hist_field,
1917			       unsigned int level)
1918{
1919	unsigned int i;
1920
1921	if (level > 3)
1922		return;
1923
1924	if (!hist_field)
1925		return;
1926
1927	if (hist_field->flags & HIST_FIELD_FL_VAR_REF)
1928		return; /* var refs will be destroyed separately */
1929
1930	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
1931		destroy_hist_field(hist_field->operands[i], level + 1);
1932
1933	__destroy_hist_field(hist_field);
1934}
1935
1936static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
1937					    struct ftrace_event_field *field,
1938					    unsigned long flags,
1939					    char *var_name)
1940{
1941	struct hist_field *hist_field;
1942
1943	if (field && is_function_field(field))
1944		return NULL;
1945
1946	hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
1947	if (!hist_field)
1948		return NULL;
1949
1950	hist_field->ref = 1;
1951
1952	hist_field->hist_data = hist_data;
1953
1954	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
1955		goto out; /* caller will populate */
1956
1957	if (flags & HIST_FIELD_FL_VAR_REF) {
1958		hist_field->fn_num = HIST_FIELD_FN_VAR_REF;
1959		goto out;
1960	}
1961
1962	if (flags & HIST_FIELD_FL_HITCOUNT) {
1963		hist_field->fn_num = HIST_FIELD_FN_COUNTER;
1964		hist_field->size = sizeof(u64);
1965		hist_field->type = "u64";
1966		goto out;
1967	}
1968
1969	if (flags & HIST_FIELD_FL_CONST) {
1970		hist_field->fn_num = HIST_FIELD_FN_CONST;
1971		hist_field->size = sizeof(u64);
1972		hist_field->type = kstrdup("u64", GFP_KERNEL);
1973		if (!hist_field->type)
1974			goto free;
1975		goto out;
1976	}
1977
1978	if (flags & HIST_FIELD_FL_STACKTRACE) {
1979		if (field)
1980			hist_field->fn_num = HIST_FIELD_FN_STACK;
1981		else
1982			hist_field->fn_num = HIST_FIELD_FN_NOP;
1983		hist_field->size = HIST_STACKTRACE_SIZE;
1984		hist_field->type = kstrdup_const("unsigned long[]", GFP_KERNEL);
1985		if (!hist_field->type)
1986			goto free;
1987		goto out;
1988	}
1989
1990	if (flags & (HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET)) {
1991		unsigned long fl = flags & ~(HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET);
1992		hist_field->fn_num = flags & HIST_FIELD_FL_LOG2 ? HIST_FIELD_FN_LOG2 :
1993			HIST_FIELD_FN_BUCKET;
1994		hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
1995		if (!hist_field->operands[0])
1996			goto free;
1997		hist_field->size = hist_field->operands[0]->size;
1998		hist_field->type = kstrdup_const(hist_field->operands[0]->type, GFP_KERNEL);
1999		if (!hist_field->type)
2000			goto free;
2001		goto out;
2002	}
2003
2004	if (flags & HIST_FIELD_FL_TIMESTAMP) {
2005		hist_field->fn_num = HIST_FIELD_FN_TIMESTAMP;
2006		hist_field->size = sizeof(u64);
2007		hist_field->type = "u64";
2008		goto out;
2009	}
2010
2011	if (flags & HIST_FIELD_FL_CPU) {
2012		hist_field->fn_num = HIST_FIELD_FN_CPU;
2013		hist_field->size = sizeof(int);
2014		hist_field->type = "unsigned int";
2015		goto out;
2016	}
2017
2018	if (WARN_ON_ONCE(!field))
2019		goto out;
2020
2021	/* Pointers to strings are just pointers and dangerous to dereference */
2022	if (is_string_field(field) &&
2023	    (field->filter_type != FILTER_PTR_STRING)) {
2024		flags |= HIST_FIELD_FL_STRING;
2025
2026		hist_field->size = MAX_FILTER_STR_VAL;
2027		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
2028		if (!hist_field->type)
2029			goto free;
2030
2031		if (field->filter_type == FILTER_STATIC_STRING) {
2032			hist_field->fn_num = HIST_FIELD_FN_STRING;
2033			hist_field->size = field->size;
2034		} else if (field->filter_type == FILTER_DYN_STRING) {
2035			hist_field->fn_num = HIST_FIELD_FN_DYNSTRING;
2036		} else if (field->filter_type == FILTER_RDYN_STRING)
2037			hist_field->fn_num = HIST_FIELD_FN_RELDYNSTRING;
2038		else
2039			hist_field->fn_num = HIST_FIELD_FN_PSTRING;
2040	} else {
2041		hist_field->size = field->size;
2042		hist_field->is_signed = field->is_signed;
2043		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
2044		if (!hist_field->type)
2045			goto free;
2046
2047		hist_field->fn_num = select_value_fn(field->size,
2048						     field->is_signed);
2049		if (hist_field->fn_num == HIST_FIELD_FN_NOP) {
2050			destroy_hist_field(hist_field, 0);
2051			return NULL;
2052		}
2053	}
2054 out:
2055	hist_field->field = field;
2056	hist_field->flags = flags;
2057
2058	if (var_name) {
2059		hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
2060		if (!hist_field->var.name)
2061			goto free;
2062	}
2063
2064	return hist_field;
2065 free:
2066	destroy_hist_field(hist_field, 0);
2067	return NULL;
2068}
2069
2070static void destroy_hist_fields(struct hist_trigger_data *hist_data)
2071{
2072	unsigned int i;
2073
2074	for (i = 0; i < HIST_FIELDS_MAX; i++) {
2075		if (hist_data->fields[i]) {
2076			destroy_hist_field(hist_data->fields[i], 0);
2077			hist_data->fields[i] = NULL;
2078		}
2079	}
2080
2081	for (i = 0; i < hist_data->n_var_refs; i++) {
2082		WARN_ON(!(hist_data->var_refs[i]->flags & HIST_FIELD_FL_VAR_REF));
2083		__destroy_hist_field(hist_data->var_refs[i]);
2084		hist_data->var_refs[i] = NULL;
2085	}
2086}
2087
2088static int init_var_ref(struct hist_field *ref_field,
2089			struct hist_field *var_field,
2090			char *system, char *event_name)
2091{
2092	int err = 0;
2093
2094	ref_field->var.idx = var_field->var.idx;
2095	ref_field->var.hist_data = var_field->hist_data;
2096	ref_field->size = var_field->size;
2097	ref_field->is_signed = var_field->is_signed;
2098	ref_field->flags |= var_field->flags &
2099		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2100
2101	if (system) {
2102		ref_field->system = kstrdup(system, GFP_KERNEL);
2103		if (!ref_field->system)
2104			return -ENOMEM;
2105	}
2106
2107	if (event_name) {
2108		ref_field->event_name = kstrdup(event_name, GFP_KERNEL);
2109		if (!ref_field->event_name) {
2110			err = -ENOMEM;
2111			goto free;
2112		}
2113	}
2114
2115	if (var_field->var.name) {
2116		ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
2117		if (!ref_field->name) {
2118			err = -ENOMEM;
2119			goto free;
2120		}
2121	} else if (var_field->name) {
2122		ref_field->name = kstrdup(var_field->name, GFP_KERNEL);
2123		if (!ref_field->name) {
2124			err = -ENOMEM;
2125			goto free;
2126		}
2127	}
2128
2129	ref_field->type = kstrdup_const(var_field->type, GFP_KERNEL);
2130	if (!ref_field->type) {
2131		err = -ENOMEM;
2132		goto free;
2133	}
2134 out:
2135	return err;
2136 free:
2137	kfree(ref_field->system);
2138	ref_field->system = NULL;
2139	kfree(ref_field->event_name);
2140	ref_field->event_name = NULL;
2141	kfree(ref_field->name);
2142	ref_field->name = NULL;
2143
2144	goto out;
2145}
2146
2147static int find_var_ref_idx(struct hist_trigger_data *hist_data,
2148			    struct hist_field *var_field)
2149{
2150	struct hist_field *ref_field;
2151	int i;
2152
2153	for (i = 0; i < hist_data->n_var_refs; i++) {
2154		ref_field = hist_data->var_refs[i];
2155		if (ref_field->var.idx == var_field->var.idx &&
2156		    ref_field->var.hist_data == var_field->hist_data)
2157			return i;
2158	}
2159
2160	return -ENOENT;
2161}
2162
2163/**
2164 * create_var_ref - Create a variable reference and attach it to trigger
2165 * @hist_data: The trigger that will be referencing the variable
2166 * @var_field: The VAR field to create a reference to
2167 * @system: The optional system string
2168 * @event_name: The optional event_name string
2169 *
2170 * Given a variable hist_field, create a VAR_REF hist_field that
2171 * represents a reference to it.
2172 *
2173 * This function also adds the reference to the trigger that
2174 * now references the variable.
2175 *
2176 * Return: The VAR_REF field if successful, NULL if not
2177 */
2178static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
2179					 struct hist_field *var_field,
2180					 char *system, char *event_name)
2181{
2182	unsigned long flags = HIST_FIELD_FL_VAR_REF;
2183	struct hist_field *ref_field;
2184	int i;
2185
2186	/* Check if the variable already exists */
2187	for (i = 0; i < hist_data->n_var_refs; i++) {
2188		ref_field = hist_data->var_refs[i];
2189		if (ref_field->var.idx == var_field->var.idx &&
2190		    ref_field->var.hist_data == var_field->hist_data) {
2191			get_hist_field(ref_field);
2192			return ref_field;
2193		}
2194	}
2195	/* Sanity check to avoid out-of-bound write on 'hist_data->var_refs' */
2196	if (hist_data->n_var_refs >= TRACING_MAP_VARS_MAX)
2197		return NULL;
2198	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
2199	if (ref_field) {
2200		if (init_var_ref(ref_field, var_field, system, event_name)) {
2201			destroy_hist_field(ref_field, 0);
2202			return NULL;
2203		}
2204
2205		hist_data->var_refs[hist_data->n_var_refs] = ref_field;
2206		ref_field->var_ref_idx = hist_data->n_var_refs++;
2207	}
2208
2209	return ref_field;
2210}
2211
2212static bool is_var_ref(char *var_name)
2213{
2214	if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
2215		return false;
2216
2217	return true;
2218}
2219
2220static char *field_name_from_var(struct hist_trigger_data *hist_data,
2221				 char *var_name)
2222{
2223	char *name, *field;
2224	unsigned int i;
2225
2226	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
2227		name = hist_data->attrs->var_defs.name[i];
2228
2229		if (strcmp(var_name, name) == 0) {
2230			field = hist_data->attrs->var_defs.expr[i];
2231			if (contains_operator(field, NULL) || is_var_ref(field))
2232				continue;
2233			return field;
2234		}
2235	}
2236
2237	return NULL;
2238}
2239
2240static char *local_field_var_ref(struct hist_trigger_data *hist_data,
2241				 char *system, char *event_name,
2242				 char *var_name)
2243{
2244	struct trace_event_call *call;
2245
2246	if (system && event_name) {
2247		call = hist_data->event_file->event_call;
2248
2249		if (strcmp(system, call->class->system) != 0)
2250			return NULL;
2251
2252		if (strcmp(event_name, trace_event_name(call)) != 0)
2253			return NULL;
2254	}
2255
2256	if (!!system != !!event_name)
2257		return NULL;
2258
2259	if (!is_var_ref(var_name))
2260		return NULL;
2261
2262	var_name++;
2263
2264	return field_name_from_var(hist_data, var_name);
2265}
2266
2267static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
2268					char *system, char *event_name,
2269					char *var_name)
2270{
2271	struct hist_field *var_field = NULL, *ref_field = NULL;
2272	struct trace_array *tr = hist_data->event_file->tr;
2273
2274	if (!is_var_ref(var_name))
2275		return NULL;
2276
2277	var_name++;
2278
2279	var_field = find_event_var(hist_data, system, event_name, var_name);
2280	if (var_field)
2281		ref_field = create_var_ref(hist_data, var_field,
2282					   system, event_name);
2283
2284	if (!ref_field)
2285		hist_err(tr, HIST_ERR_VAR_NOT_FOUND, errpos(var_name));
2286
2287	return ref_field;
2288}
2289
2290static struct ftrace_event_field *
2291parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
2292	    char *field_str, unsigned long *flags, unsigned long *buckets)
2293{
2294	struct ftrace_event_field *field = NULL;
2295	char *field_name, *modifier, *str;
2296	struct trace_array *tr = file->tr;
2297
2298	modifier = str = kstrdup(field_str, GFP_KERNEL);
2299	if (!modifier)
2300		return ERR_PTR(-ENOMEM);
2301
2302	field_name = strsep(&modifier, ".");
2303	if (modifier) {
2304		if (strcmp(modifier, "hex") == 0)
2305			*flags |= HIST_FIELD_FL_HEX;
2306		else if (strcmp(modifier, "sym") == 0)
2307			*flags |= HIST_FIELD_FL_SYM;
2308		/*
2309		 * 'sym-offset' occurrences in the trigger string are modified
2310		 * to 'symXoffset' to simplify arithmetic expression parsing.
2311		 */
2312		else if (strcmp(modifier, "symXoffset") == 0)
2313			*flags |= HIST_FIELD_FL_SYM_OFFSET;
2314		else if ((strcmp(modifier, "execname") == 0) &&
2315			 (strcmp(field_name, "common_pid") == 0))
2316			*flags |= HIST_FIELD_FL_EXECNAME;
2317		else if (strcmp(modifier, "syscall") == 0)
2318			*flags |= HIST_FIELD_FL_SYSCALL;
2319		else if (strcmp(modifier, "stacktrace") == 0)
2320			*flags |= HIST_FIELD_FL_STACKTRACE;
2321		else if (strcmp(modifier, "log2") == 0)
2322			*flags |= HIST_FIELD_FL_LOG2;
2323		else if (strcmp(modifier, "usecs") == 0)
2324			*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
2325		else if (strncmp(modifier, "bucket", 6) == 0) {
2326			int ret;
2327
2328			modifier += 6;
2329
2330			if (*modifier == 's')
2331				modifier++;
2332			if (*modifier != '=')
2333				goto error;
2334			modifier++;
2335			ret = kstrtoul(modifier, 0, buckets);
2336			if (ret || !(*buckets))
2337				goto error;
2338			*flags |= HIST_FIELD_FL_BUCKET;
2339		} else if (strncmp(modifier, "percent", 7) == 0) {
2340			if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
2341				goto error;
2342			*flags |= HIST_FIELD_FL_PERCENT;
2343		} else if (strncmp(modifier, "graph", 5) == 0) {
2344			if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
2345				goto error;
2346			*flags |= HIST_FIELD_FL_GRAPH;
2347		} else {
2348 error:
2349			hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
2350			field = ERR_PTR(-EINVAL);
2351			goto out;
2352		}
2353	}
2354
2355	if (strcmp(field_name, "common_timestamp") == 0) {
2356		*flags |= HIST_FIELD_FL_TIMESTAMP;
2357		hist_data->enable_timestamps = true;
2358		if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2359			hist_data->attrs->ts_in_usecs = true;
2360	} else if (strcmp(field_name, "common_stacktrace") == 0) {
2361		*flags |= HIST_FIELD_FL_STACKTRACE;
2362	} else if (strcmp(field_name, "common_cpu") == 0)
2363		*flags |= HIST_FIELD_FL_CPU;
2364	else if (strcmp(field_name, "hitcount") == 0)
2365		*flags |= HIST_FIELD_FL_HITCOUNT;
2366	else {
2367		field = trace_find_event_field(file->event_call, field_name);
2368		if (!field || !field->size) {
2369			/*
2370			 * For backward compatibility, if field_name
2371			 * was "cpu" or "stacktrace", then we treat this
2372			 * the same as common_cpu and common_stacktrace
2373			 * respectively. This also works for "CPU", and
2374			 * "STACKTRACE".
2375			 */
2376			if (field && field->filter_type == FILTER_CPU) {
2377				*flags |= HIST_FIELD_FL_CPU;
2378			} else if (field && field->filter_type == FILTER_STACKTRACE) {
2379				*flags |= HIST_FIELD_FL_STACKTRACE;
2380			} else {
2381				hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,
2382					 errpos(field_name));
2383				field = ERR_PTR(-EINVAL);
2384				goto out;
2385			}
2386		}
2387	}
2388 out:
2389	kfree(str);
2390
2391	return field;
2392}
2393
2394static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
2395				       struct hist_field *var_ref,
2396				       char *var_name)
2397{
2398	struct hist_field *alias = NULL;
2399	unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;
2400
2401	alias = create_hist_field(hist_data, NULL, flags, var_name);
2402	if (!alias)
2403		return NULL;
2404
2405	alias->fn_num = var_ref->fn_num;
2406	alias->operands[0] = var_ref;
2407
2408	if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
2409		destroy_hist_field(alias, 0);
2410		return NULL;
2411	}
2412
2413	alias->var_ref_idx = var_ref->var_ref_idx;
2414
2415	return alias;
2416}
2417
2418static struct hist_field *parse_const(struct hist_trigger_data *hist_data,
2419				      char *str, char *var_name,
2420				      unsigned long *flags)
2421{
2422	struct trace_array *tr = hist_data->event_file->tr;
2423	struct hist_field *field = NULL;
2424	u64 constant;
2425
2426	if (kstrtoull(str, 0, &constant)) {
2427		hist_err(tr, HIST_ERR_EXPECT_NUMBER, errpos(str));
2428		return NULL;
2429	}
2430
2431	*flags |= HIST_FIELD_FL_CONST;
2432	field = create_hist_field(hist_data, NULL, *flags, var_name);
2433	if (!field)
2434		return NULL;
2435
2436	field->constant = constant;
2437
2438	return field;
2439}
2440
2441static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
2442				     struct trace_event_file *file, char *str,
2443				     unsigned long *flags, char *var_name)
2444{
2445	char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
2446	struct ftrace_event_field *field = NULL;
2447	struct hist_field *hist_field = NULL;
2448	unsigned long buckets = 0;
2449	int ret = 0;
2450
2451	if (isdigit(str[0])) {
2452		hist_field = parse_const(hist_data, str, var_name, flags);
2453		if (!hist_field) {
2454			ret = -EINVAL;
2455			goto out;
2456		}
2457		return hist_field;
2458	}
2459
2460	s = strchr(str, '.');
2461	if (s) {
2462		s = strchr(++s, '.');
2463		if (s) {
2464			ref_system = strsep(&str, ".");
2465			if (!str) {
2466				ret = -EINVAL;
2467				goto out;
2468			}
2469			ref_event = strsep(&str, ".");
2470			if (!str) {
2471				ret = -EINVAL;
2472				goto out;
2473			}
2474			ref_var = str;
2475		}
2476	}
2477
2478	s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
2479	if (!s) {
2480		hist_field = parse_var_ref(hist_data, ref_system,
2481					   ref_event, ref_var);
2482		if (hist_field) {
2483			if (var_name) {
2484				hist_field = create_alias(hist_data, hist_field, var_name);
2485				if (!hist_field) {
2486					ret = -ENOMEM;
2487					goto out;
2488				}
2489			}
2490			return hist_field;
2491		}
2492	} else
2493		str = s;
2494
2495	field = parse_field(hist_data, file, str, flags, &buckets);
2496	if (IS_ERR(field)) {
2497		ret = PTR_ERR(field);
2498		goto out;
2499	}
2500
2501	hist_field = create_hist_field(hist_data, field, *flags, var_name);
2502	if (!hist_field) {
2503		ret = -ENOMEM;
2504		goto out;
2505	}
2506	hist_field->buckets = buckets;
2507
2508	return hist_field;
2509 out:
2510	return ERR_PTR(ret);
2511}
2512
2513static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2514				     struct trace_event_file *file,
2515				     char *str, unsigned long flags,
2516				     char *var_name, unsigned int *n_subexprs);
2517
2518static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
2519				      struct trace_event_file *file,
2520				      char *str, unsigned long flags,
2521				      char *var_name, unsigned int *n_subexprs)
2522{
2523	struct hist_field *operand1, *expr = NULL;
2524	unsigned long operand_flags;
2525	int ret = 0;
2526	char *s;
2527
2528	/* Unary minus operator, increment n_subexprs */
2529	++*n_subexprs;
2530
2531	/* we support only -(xxx) i.e. explicit parens required */
2532
2533	if (*n_subexprs > 3) {
2534		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2535		ret = -EINVAL;
2536		goto free;
2537	}
2538
2539	str++; /* skip leading '-' */
2540
2541	s = strchr(str, '(');
2542	if (s)
2543		str++;
2544	else {
2545		ret = -EINVAL;
2546		goto free;
2547	}
2548
2549	s = strrchr(str, ')');
2550	if (s) {
2551		 /* unary minus not supported in sub-expressions */
2552		if (*(s+1) != '\0') {
2553			hist_err(file->tr, HIST_ERR_UNARY_MINUS_SUBEXPR,
2554				 errpos(str));
2555			ret = -EINVAL;
2556			goto free;
2557		}
2558		*s = '\0';
2559	}
2560	else {
2561		ret = -EINVAL; /* no closing ')' */
2562		goto free;
2563	}
2564
2565	flags |= HIST_FIELD_FL_EXPR;
2566	expr = create_hist_field(hist_data, NULL, flags, var_name);
2567	if (!expr) {
2568		ret = -ENOMEM;
2569		goto free;
2570	}
2571
2572	operand_flags = 0;
2573	operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2574	if (IS_ERR(operand1)) {
2575		ret = PTR_ERR(operand1);
2576		goto free;
2577	}
2578	if (operand1->flags & HIST_FIELD_FL_STRING) {
2579		/* String type can not be the operand of unary operator. */
2580		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2581		destroy_hist_field(operand1, 0);
2582		ret = -EINVAL;
2583		goto free;
2584	}
2585
2586	expr->flags |= operand1->flags &
2587		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2588	expr->fn_num = HIST_FIELD_FN_UMINUS;
2589	expr->operands[0] = operand1;
2590	expr->size = operand1->size;
2591	expr->is_signed = operand1->is_signed;
2592	expr->operator = FIELD_OP_UNARY_MINUS;
2593	expr->name = expr_str(expr, 0);
2594	expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2595	if (!expr->type) {
2596		ret = -ENOMEM;
2597		goto free;
2598	}
2599
2600	return expr;
2601 free:
2602	destroy_hist_field(expr, 0);
2603	return ERR_PTR(ret);
2604}
2605
2606/*
2607 * If the operands are var refs, return pointers the
2608 * variable(s) referenced in var1 and var2, else NULL.
2609 */
2610static int check_expr_operands(struct trace_array *tr,
2611			       struct hist_field *operand1,
2612			       struct hist_field *operand2,
2613			       struct hist_field **var1,
2614			       struct hist_field **var2)
2615{
2616	unsigned long operand1_flags = operand1->flags;
2617	unsigned long operand2_flags = operand2->flags;
2618
2619	if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
2620	    (operand1_flags & HIST_FIELD_FL_ALIAS)) {
2621		struct hist_field *var;
2622
2623		var = find_var_field(operand1->var.hist_data, operand1->name);
2624		if (!var)
2625			return -EINVAL;
2626		operand1_flags = var->flags;
2627		*var1 = var;
2628	}
2629
2630	if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
2631	    (operand2_flags & HIST_FIELD_FL_ALIAS)) {
2632		struct hist_field *var;
2633
2634		var = find_var_field(operand2->var.hist_data, operand2->name);
2635		if (!var)
2636			return -EINVAL;
2637		operand2_flags = var->flags;
2638		*var2 = var;
2639	}
2640
2641	if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
2642	    (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
2643		hist_err(tr, HIST_ERR_TIMESTAMP_MISMATCH, 0);
2644		return -EINVAL;
2645	}
2646
2647	return 0;
2648}
2649
2650static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2651				     struct trace_event_file *file,
2652				     char *str, unsigned long flags,
2653				     char *var_name, unsigned int *n_subexprs)
2654{
2655	struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
2656	struct hist_field *var1 = NULL, *var2 = NULL;
2657	unsigned long operand_flags, operand2_flags;
2658	int field_op, ret = -EINVAL;
2659	char *sep, *operand1_str;
2660	enum hist_field_fn op_fn;
2661	bool combine_consts;
2662
2663	if (*n_subexprs > 3) {
2664		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2665		return ERR_PTR(-EINVAL);
2666	}
2667
2668	field_op = contains_operator(str, &sep);
2669
2670	if (field_op == FIELD_OP_NONE)
2671		return parse_atom(hist_data, file, str, &flags, var_name);
2672
2673	if (field_op == FIELD_OP_UNARY_MINUS)
2674		return parse_unary(hist_data, file, str, flags, var_name, n_subexprs);
2675
2676	/* Binary operator found, increment n_subexprs */
2677	++*n_subexprs;
2678
2679	/* Split the expression string at the root operator */
2680	if (!sep)
2681		return ERR_PTR(-EINVAL);
2682
2683	*sep = '\0';
2684	operand1_str = str;
2685	str = sep+1;
2686
2687	/* Binary operator requires both operands */
2688	if (*operand1_str == '\0' || *str == '\0')
2689		return ERR_PTR(-EINVAL);
2690
2691	operand_flags = 0;
2692
2693	/* LHS of string is an expression e.g. a+b in a+b+c */
2694	operand1 = parse_expr(hist_data, file, operand1_str, operand_flags, NULL, n_subexprs);
2695	if (IS_ERR(operand1))
2696		return ERR_CAST(operand1);
2697
2698	if (operand1->flags & HIST_FIELD_FL_STRING) {
2699		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(operand1_str));
2700		ret = -EINVAL;
2701		goto free_op1;
2702	}
2703
2704	/* RHS of string is another expression e.g. c in a+b+c */
2705	operand_flags = 0;
2706	operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2707	if (IS_ERR(operand2)) {
2708		ret = PTR_ERR(operand2);
2709		goto free_op1;
2710	}
2711	if (operand2->flags & HIST_FIELD_FL_STRING) {
2712		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2713		ret = -EINVAL;
2714		goto free_operands;
2715	}
2716
2717	switch (field_op) {
2718	case FIELD_OP_MINUS:
2719		op_fn = HIST_FIELD_FN_MINUS;
2720		break;
2721	case FIELD_OP_PLUS:
2722		op_fn = HIST_FIELD_FN_PLUS;
2723		break;
2724	case FIELD_OP_DIV:
2725		op_fn = HIST_FIELD_FN_DIV;
2726		break;
2727	case FIELD_OP_MULT:
2728		op_fn = HIST_FIELD_FN_MULT;
2729		break;
2730	default:
2731		ret = -EINVAL;
2732		goto free_operands;
2733	}
2734
2735	ret = check_expr_operands(file->tr, operand1, operand2, &var1, &var2);
2736	if (ret)
2737		goto free_operands;
2738
2739	operand_flags = var1 ? var1->flags : operand1->flags;
2740	operand2_flags = var2 ? var2->flags : operand2->flags;
2741
2742	/*
2743	 * If both operands are constant, the expression can be
2744	 * collapsed to a single constant.
2745	 */
2746	combine_consts = operand_flags & operand2_flags & HIST_FIELD_FL_CONST;
2747
2748	flags |= combine_consts ? HIST_FIELD_FL_CONST : HIST_FIELD_FL_EXPR;
2749
2750	flags |= operand1->flags &
2751		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2752
2753	expr = create_hist_field(hist_data, NULL, flags, var_name);
2754	if (!expr) {
2755		ret = -ENOMEM;
2756		goto free_operands;
2757	}
2758
2759	operand1->read_once = true;
2760	operand2->read_once = true;
2761
2762	/* The operands are now owned and free'd by 'expr' */
2763	expr->operands[0] = operand1;
2764	expr->operands[1] = operand2;
2765
2766	if (field_op == FIELD_OP_DIV &&
2767			operand2_flags & HIST_FIELD_FL_CONST) {
2768		u64 divisor = var2 ? var2->constant : operand2->constant;
2769
2770		if (!divisor) {
2771			hist_err(file->tr, HIST_ERR_DIVISION_BY_ZERO, errpos(str));
2772			ret = -EDOM;
2773			goto free_expr;
2774		}
2775
2776		/*
2777		 * Copy the divisor here so we don't have to look it up
2778		 * later if this is a var ref
2779		 */
2780		operand2->constant = divisor;
2781		op_fn = hist_field_get_div_fn(operand2);
2782	}
2783
2784	expr->fn_num = op_fn;
2785
2786	if (combine_consts) {
2787		if (var1)
2788			expr->operands[0] = var1;
2789		if (var2)
2790			expr->operands[1] = var2;
2791
2792		expr->constant = hist_fn_call(expr, NULL, NULL, NULL, NULL);
2793		expr->fn_num = HIST_FIELD_FN_CONST;
2794
2795		expr->operands[0] = NULL;
2796		expr->operands[1] = NULL;
2797
2798		/*
2799		 * var refs won't be destroyed immediately
2800		 * See: destroy_hist_field()
2801		 */
2802		destroy_hist_field(operand2, 0);
2803		destroy_hist_field(operand1, 0);
2804
2805		expr->name = expr_str(expr, 0);
2806	} else {
2807		/* The operand sizes should be the same, so just pick one */
2808		expr->size = operand1->size;
2809		expr->is_signed = operand1->is_signed;
2810
2811		expr->operator = field_op;
2812		expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2813		if (!expr->type) {
2814			ret = -ENOMEM;
2815			goto free_expr;
2816		}
2817
2818		expr->name = expr_str(expr, 0);
2819	}
2820
2821	return expr;
2822
2823free_operands:
2824	destroy_hist_field(operand2, 0);
2825free_op1:
2826	destroy_hist_field(operand1, 0);
2827	return ERR_PTR(ret);
2828
2829free_expr:
2830	destroy_hist_field(expr, 0);
2831	return ERR_PTR(ret);
2832}
2833
2834static char *find_trigger_filter(struct hist_trigger_data *hist_data,
2835				 struct trace_event_file *file)
2836{
2837	struct event_trigger_data *test;
2838
2839	lockdep_assert_held(&event_mutex);
2840
2841	list_for_each_entry(test, &file->triggers, list) {
2842		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2843			if (test->private_data == hist_data)
2844				return test->filter_str;
2845		}
2846	}
2847
2848	return NULL;
2849}
2850
2851static struct event_command trigger_hist_cmd;
2852static int event_hist_trigger_parse(struct event_command *cmd_ops,
2853				    struct trace_event_file *file,
2854				    char *glob, char *cmd,
2855				    char *param_and_filter);
2856
2857static bool compatible_keys(struct hist_trigger_data *target_hist_data,
2858			    struct hist_trigger_data *hist_data,
2859			    unsigned int n_keys)
2860{
2861	struct hist_field *target_hist_field, *hist_field;
2862	unsigned int n, i, j;
2863
2864	if (hist_data->n_fields - hist_data->n_vals != n_keys)
2865		return false;
2866
2867	i = hist_data->n_vals;
2868	j = target_hist_data->n_vals;
2869
2870	for (n = 0; n < n_keys; n++) {
2871		hist_field = hist_data->fields[i + n];
2872		target_hist_field = target_hist_data->fields[j + n];
2873
2874		if (strcmp(hist_field->type, target_hist_field->type) != 0)
2875			return false;
2876		if (hist_field->size != target_hist_field->size)
2877			return false;
2878		if (hist_field->is_signed != target_hist_field->is_signed)
2879			return false;
2880	}
2881
2882	return true;
2883}
2884
2885static struct hist_trigger_data *
2886find_compatible_hist(struct hist_trigger_data *target_hist_data,
2887		     struct trace_event_file *file)
2888{
2889	struct hist_trigger_data *hist_data;
2890	struct event_trigger_data *test;
2891	unsigned int n_keys;
2892
2893	lockdep_assert_held(&event_mutex);
2894
2895	n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
2896
2897	list_for_each_entry(test, &file->triggers, list) {
2898		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2899			hist_data = test->private_data;
2900
2901			if (compatible_keys(target_hist_data, hist_data, n_keys))
2902				return hist_data;
2903		}
2904	}
2905
2906	return NULL;
2907}
2908
2909static struct trace_event_file *event_file(struct trace_array *tr,
2910					   char *system, char *event_name)
2911{
2912	struct trace_event_file *file;
2913
2914	file = __find_event_file(tr, system, event_name);
2915	if (!file)
2916		return ERR_PTR(-EINVAL);
2917
2918	return file;
2919}
2920
2921static struct hist_field *
2922find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
2923			 char *system, char *event_name, char *field_name)
2924{
2925	struct hist_field *event_var;
2926	char *synthetic_name;
2927
2928	synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2929	if (!synthetic_name)
2930		return ERR_PTR(-ENOMEM);
2931
2932	strcpy(synthetic_name, "synthetic_");
2933	strcat(synthetic_name, field_name);
2934
2935	event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);
2936
2937	kfree(synthetic_name);
2938
2939	return event_var;
2940}
2941
2942/**
2943 * create_field_var_hist - Automatically create a histogram and var for a field
2944 * @target_hist_data: The target hist trigger
2945 * @subsys_name: Optional subsystem name
2946 * @event_name: Optional event name
2947 * @field_name: The name of the field (and the resulting variable)
2948 *
2949 * Hist trigger actions fetch data from variables, not directly from
2950 * events.  However, for convenience, users are allowed to directly
2951 * specify an event field in an action, which will be automatically
2952 * converted into a variable on their behalf.
2953 *
2954 * If a user specifies a field on an event that isn't the event the
2955 * histogram currently being defined (the target event histogram), the
2956 * only way that can be accomplished is if a new hist trigger is
2957 * created and the field variable defined on that.
2958 *
2959 * This function creates a new histogram compatible with the target
2960 * event (meaning a histogram with the same key as the target
2961 * histogram), and creates a variable for the specified field, but
2962 * with 'synthetic_' prepended to the variable name in order to avoid
2963 * collision with normal field variables.
2964 *
2965 * Return: The variable created for the field.
2966 */
2967static struct hist_field *
2968create_field_var_hist(struct hist_trigger_data *target_hist_data,
2969		      char *subsys_name, char *event_name, char *field_name)
2970{
2971	struct trace_array *tr = target_hist_data->event_file->tr;
2972	struct hist_trigger_data *hist_data;
2973	unsigned int i, n, first = true;
2974	struct field_var_hist *var_hist;
2975	struct trace_event_file *file;
2976	struct hist_field *key_field;
2977	struct hist_field *event_var;
2978	char *saved_filter;
2979	char *cmd;
2980	int ret;
2981
2982	if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
2983		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
2984		return ERR_PTR(-EINVAL);
2985	}
2986
2987	file = event_file(tr, subsys_name, event_name);
2988
2989	if (IS_ERR(file)) {
2990		hist_err(tr, HIST_ERR_EVENT_FILE_NOT_FOUND, errpos(field_name));
2991		ret = PTR_ERR(file);
2992		return ERR_PTR(ret);
2993	}
2994
2995	/*
2996	 * Look for a histogram compatible with target.  We'll use the
2997	 * found histogram specification to create a new matching
2998	 * histogram with our variable on it.  target_hist_data is not
2999	 * yet a registered histogram so we can't use that.
3000	 */
3001	hist_data = find_compatible_hist(target_hist_data, file);
3002	if (!hist_data) {
3003		hist_err(tr, HIST_ERR_HIST_NOT_FOUND, errpos(field_name));
3004		return ERR_PTR(-EINVAL);
3005	}
3006
3007	/* See if a synthetic field variable has already been created */
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		return event_var;
3012
3013	var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
3014	if (!var_hist)
3015		return ERR_PTR(-ENOMEM);
3016
3017	cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
3018	if (!cmd) {
3019		kfree(var_hist);
3020		return ERR_PTR(-ENOMEM);
3021	}
3022
3023	/* Use the same keys as the compatible histogram */
3024	strcat(cmd, "keys=");
3025
3026	for_each_hist_key_field(i, hist_data) {
3027		key_field = hist_data->fields[i];
3028		if (!first)
3029			strcat(cmd, ",");
3030		strcat(cmd, key_field->field->name);
3031		first = false;
3032	}
3033
3034	/* Create the synthetic field variable specification */
3035	strcat(cmd, ":synthetic_");
3036	strcat(cmd, field_name);
3037	strcat(cmd, "=");
3038	strcat(cmd, field_name);
3039
3040	/* Use the same filter as the compatible histogram */
3041	saved_filter = find_trigger_filter(hist_data, file);
3042	if (saved_filter) {
3043		strcat(cmd, " if ");
3044		strcat(cmd, saved_filter);
3045	}
3046
3047	var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
3048	if (!var_hist->cmd) {
3049		kfree(cmd);
3050		kfree(var_hist);
3051		return ERR_PTR(-ENOMEM);
3052	}
3053
3054	/* Save the compatible histogram information */
3055	var_hist->hist_data = hist_data;
3056
3057	/* Create the new histogram with our variable */
3058	ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
3059				       "", "hist", cmd);
3060	if (ret) {
3061		kfree(cmd);
3062		kfree(var_hist->cmd);
3063		kfree(var_hist);
3064		hist_err(tr, HIST_ERR_HIST_CREATE_FAIL, errpos(field_name));
3065		return ERR_PTR(ret);
3066	}
3067
3068	kfree(cmd);
3069
3070	/* If we can't find the variable, something went wrong */
3071	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
3072					     event_name, field_name);
3073	if (IS_ERR_OR_NULL(event_var)) {
3074		kfree(var_hist->cmd);
3075		kfree(var_hist);
3076		hist_err(tr, HIST_ERR_SYNTH_VAR_NOT_FOUND, errpos(field_name));
3077		return ERR_PTR(-EINVAL);
3078	}
3079
3080	n = target_hist_data->n_field_var_hists;
3081	target_hist_data->field_var_hists[n] = var_hist;
3082	target_hist_data->n_field_var_hists++;
3083
3084	return event_var;
3085}
3086
3087static struct hist_field *
3088find_target_event_var(struct hist_trigger_data *hist_data,
3089		      char *subsys_name, char *event_name, char *var_name)
3090{
3091	struct trace_event_file *file = hist_data->event_file;
3092	struct hist_field *hist_field = NULL;
3093
3094	if (subsys_name) {
3095		struct trace_event_call *call;
3096
3097		if (!event_name)
3098			return NULL;
3099
3100		call = file->event_call;
3101
3102		if (strcmp(subsys_name, call->class->system) != 0)
3103			return NULL;
3104
3105		if (strcmp(event_name, trace_event_name(call)) != 0)
3106			return NULL;
3107	}
3108
3109	hist_field = find_var_field(hist_data, var_name);
3110
3111	return hist_field;
3112}
3113
3114static inline void __update_field_vars(struct tracing_map_elt *elt,
3115				       struct trace_buffer *buffer,
3116				       struct ring_buffer_event *rbe,
3117				       void *rec,
3118				       struct field_var **field_vars,
3119				       unsigned int n_field_vars,
3120				       unsigned int field_var_str_start)
3121{
3122	struct hist_elt_data *elt_data = elt->private_data;
3123	unsigned int i, j, var_idx;
3124	u64 var_val;
3125
3126	/* Make sure stacktrace can fit in the string variable length */
3127	BUILD_BUG_ON((HIST_STACKTRACE_DEPTH + 1) * sizeof(long) >= STR_VAR_LEN_MAX);
3128
3129	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
3130		struct field_var *field_var = field_vars[i];
3131		struct hist_field *var = field_var->var;
3132		struct hist_field *val = field_var->val;
3133
3134		var_val = hist_fn_call(val, elt, buffer, rbe, rec);
3135		var_idx = var->var.idx;
3136
3137		if (val->flags & (HIST_FIELD_FL_STRING |
3138				  HIST_FIELD_FL_STACKTRACE)) {
3139			char *str = elt_data->field_var_str[j++];
3140			char *val_str = (char *)(uintptr_t)var_val;
3141			unsigned int size;
3142
3143			if (val->flags & HIST_FIELD_FL_STRING) {
3144				size = min(val->size, STR_VAR_LEN_MAX);
3145				strscpy(str, val_str, size);
3146			} else {
3147				char *stack_start = str + sizeof(unsigned long);
3148				int e;
3149
3150				e = stack_trace_save((void *)stack_start,
3151						     HIST_STACKTRACE_DEPTH,
3152						     HIST_STACKTRACE_SKIP);
3153				if (e < HIST_STACKTRACE_DEPTH - 1)
3154					((unsigned long *)stack_start)[e] = 0;
3155				*((unsigned long *)str) = e;
3156			}
3157			var_val = (u64)(uintptr_t)str;
3158		}
3159		tracing_map_set_var(elt, var_idx, var_val);
3160	}
3161}
3162
3163static void update_field_vars(struct hist_trigger_data *hist_data,
3164			      struct tracing_map_elt *elt,
3165			      struct trace_buffer *buffer,
3166			      struct ring_buffer_event *rbe,
3167			      void *rec)
3168{
3169	__update_field_vars(elt, buffer, rbe, rec, hist_data->field_vars,
3170			    hist_data->n_field_vars, 0);
3171}
3172
3173static void save_track_data_vars(struct hist_trigger_data *hist_data,
3174				 struct tracing_map_elt *elt,
3175				 struct trace_buffer *buffer,  void *rec,
3176				 struct ring_buffer_event *rbe, void *key,
3177				 struct action_data *data, u64 *var_ref_vals)
3178{
3179	__update_field_vars(elt, buffer, rbe, rec, hist_data->save_vars,
3180			    hist_data->n_save_vars, hist_data->n_field_var_str);
3181}
3182
3183static struct hist_field *create_var(struct hist_trigger_data *hist_data,
3184				     struct trace_event_file *file,
3185				     char *name, int size, const char *type)
3186{
3187	struct hist_field *var;
3188	int idx;
3189
3190	if (find_var(hist_data, file, name) && !hist_data->remove) {
3191		var = ERR_PTR(-EINVAL);
3192		goto out;
3193	}
3194
3195	var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
3196	if (!var) {
3197		var = ERR_PTR(-ENOMEM);
3198		goto out;
3199	}
3200
3201	idx = tracing_map_add_var(hist_data->map);
3202	if (idx < 0) {
3203		kfree(var);
3204		var = ERR_PTR(-EINVAL);
3205		goto out;
3206	}
3207
3208	var->ref = 1;
3209	var->flags = HIST_FIELD_FL_VAR;
3210	var->var.idx = idx;
3211	var->var.hist_data = var->hist_data = hist_data;
3212	var->size = size;
3213	var->var.name = kstrdup(name, GFP_KERNEL);
3214	var->type = kstrdup_const(type, GFP_KERNEL);
3215	if (!var->var.name || !var->type) {
3216		kfree_const(var->type);
3217		kfree(var->var.name);
3218		kfree(var);
3219		var = ERR_PTR(-ENOMEM);
3220	}
3221 out:
3222	return var;
3223}
3224
3225static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
3226					  struct trace_event_file *file,
3227					  char *field_name)
3228{
3229	struct hist_field *val = NULL, *var = NULL;
3230	unsigned long flags = HIST_FIELD_FL_VAR;
3231	struct trace_array *tr = file->tr;
3232	struct field_var *field_var;
3233	int ret = 0;
3234
3235	if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
3236		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
3237		ret = -EINVAL;
3238		goto err;
3239	}
3240
3241	val = parse_atom(hist_data, file, field_name, &flags, NULL);
3242	if (IS_ERR(val)) {
3243		hist_err(tr, HIST_ERR_FIELD_VAR_PARSE_FAIL, errpos(field_name));
3244		ret = PTR_ERR(val);
3245		goto err;
3246	}
3247
3248	var = create_var(hist_data, file, field_name, val->size, val->type);
3249	if (IS_ERR(var)) {
3250		hist_err(tr, HIST_ERR_VAR_CREATE_FIND_FAIL, errpos(field_name));
3251		kfree(val);
3252		ret = PTR_ERR(var);
3253		goto err;
3254	}
3255
3256	field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
3257	if (!field_var) {
3258		kfree(val);
3259		kfree(var);
3260		ret =  -ENOMEM;
3261		goto err;
3262	}
3263
3264	field_var->var = var;
3265	field_var->val = val;
3266 out:
3267	return field_var;
3268 err:
3269	field_var = ERR_PTR(ret);
3270	goto out;
3271}
3272
3273/**
3274 * create_target_field_var - Automatically create a variable for a field
3275 * @target_hist_data: The target hist trigger
3276 * @subsys_name: Optional subsystem name
3277 * @event_name: Optional event name
3278 * @var_name: The name of the field (and the resulting variable)
3279 *
3280 * Hist trigger actions fetch data from variables, not directly from
3281 * events.  However, for convenience, users are allowed to directly
3282 * specify an event field in an action, which will be automatically
3283 * converted into a variable on their behalf.
3284 *
3285 * This function creates a field variable with the name var_name on
3286 * the hist trigger currently being defined on the target event.  If
3287 * subsys_name and event_name are specified, this function simply
3288 * verifies that they do in fact match the target event subsystem and
3289 * event name.
3290 *
3291 * Return: The variable created for the field.
3292 */
3293static struct field_var *
3294create_target_field_var(struct hist_trigger_data *target_hist_data,
3295			char *subsys_name, char *event_name, char *var_name)
3296{
3297	struct trace_event_file *file = target_hist_data->event_file;
3298
3299	if (subsys_name) {
3300		struct trace_event_call *call;
3301
3302		if (!event_name)
3303			return NULL;
3304
3305		call = file->event_call;
3306
3307		if (strcmp(subsys_name, call->class->system) != 0)
3308			return NULL;
3309
3310		if (strcmp(event_name, trace_event_name(call)) != 0)
3311			return NULL;
3312	}
3313
3314	return create_field_var(target_hist_data, file, var_name);
3315}
3316
3317static bool check_track_val_max(u64 track_val, u64 var_val)
3318{
3319	if (var_val <= track_val)
3320		return false;
3321
3322	return true;
3323}
3324
3325static bool check_track_val_changed(u64 track_val, u64 var_val)
3326{
3327	if (var_val == track_val)
3328		return false;
3329
3330	return true;
3331}
3332
3333static u64 get_track_val(struct hist_trigger_data *hist_data,
3334			 struct tracing_map_elt *elt,
3335			 struct action_data *data)
3336{
3337	unsigned int track_var_idx = data->track_data.track_var->var.idx;
3338	u64 track_val;
3339
3340	track_val = tracing_map_read_var(elt, track_var_idx);
3341
3342	return track_val;
3343}
3344
3345static void save_track_val(struct hist_trigger_data *hist_data,
3346			   struct tracing_map_elt *elt,
3347			   struct action_data *data, u64 var_val)
3348{
3349	unsigned int track_var_idx = data->track_data.track_var->var.idx;
3350
3351	tracing_map_set_var(elt, track_var_idx, var_val);
3352}
3353
3354static void save_track_data(struct hist_trigger_data *hist_data,
3355			    struct tracing_map_elt *elt,
3356			    struct trace_buffer *buffer, void *rec,
3357			    struct ring_buffer_event *rbe, void *key,
3358			    struct action_data *data, u64 *var_ref_vals)
3359{
3360	if (data->track_data.save_data)
3361		data->track_data.save_data(hist_data, elt, buffer, rec, rbe,
3362					   key, data, var_ref_vals);
3363}
3364
3365static bool check_track_val(struct tracing_map_elt *elt,
3366			    struct action_data *data,
3367			    u64 var_val)
3368{
3369	struct hist_trigger_data *hist_data;
3370	u64 track_val;
3371
3372	hist_data = data->track_data.track_var->hist_data;
3373	track_val = get_track_val(hist_data, elt, data);
3374
3375	return data->track_data.check_val(track_val, var_val);
3376}
3377
3378#ifdef CONFIG_TRACER_SNAPSHOT
3379static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3380{
3381	/* called with tr->max_lock held */
3382	struct track_data *track_data = tr->cond_snapshot->cond_data;
3383	struct hist_elt_data *elt_data, *track_elt_data;
3384	struct snapshot_context *context = cond_data;
3385	struct action_data *action;
3386	u64 track_val;
3387
3388	if (!track_data)
3389		return false;
3390
3391	action = track_data->action_data;
3392
3393	track_val = get_track_val(track_data->hist_data, context->elt,
3394				  track_data->action_data);
3395
3396	if (!action->track_data.check_val(track_data->track_val, track_val))
3397		return false;
3398
3399	track_data->track_val = track_val;
3400	memcpy(track_data->key, context->key, track_data->key_len);
3401
3402	elt_data = context->elt->private_data;
3403	track_elt_data = track_data->elt.private_data;
3404	if (elt_data->comm)
3405		strscpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
3406
3407	track_data->updated = true;
3408
3409	return true;
3410}
3411
3412static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3413				     struct tracing_map_elt *elt,
3414				     struct trace_buffer *buffer, void *rec,
3415				     struct ring_buffer_event *rbe, void *key,
3416				     struct action_data *data,
3417				     u64 *var_ref_vals)
3418{
3419	struct trace_event_file *file = hist_data->event_file;
3420	struct snapshot_context context;
3421
3422	context.elt = elt;
3423	context.key = key;
3424
3425	tracing_snapshot_cond(file->tr, &context);
3426}
3427
3428static void hist_trigger_print_key(struct seq_file *m,
3429				   struct hist_trigger_data *hist_data,
3430				   void *key,
3431				   struct tracing_map_elt *elt);
3432
3433static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
3434{
3435	unsigned int i;
3436
3437	if (!hist_data->n_actions)
3438		return NULL;
3439
3440	for (i = 0; i < hist_data->n_actions; i++) {
3441		struct action_data *data = hist_data->actions[i];
3442
3443		if (data->action == ACTION_SNAPSHOT)
3444			return data;
3445	}
3446
3447	return NULL;
3448}
3449
3450static void track_data_snapshot_print(struct seq_file *m,
3451				      struct hist_trigger_data *hist_data)
3452{
3453	struct trace_event_file *file = hist_data->event_file;
3454	struct track_data *track_data;
3455	struct action_data *action;
3456
3457	track_data = tracing_cond_snapshot_data(file->tr);
3458	if (!track_data)
3459		return;
3460
3461	if (!track_data->updated)
3462		return;
3463
3464	action = snapshot_action(hist_data);
3465	if (!action)
3466		return;
3467
3468	seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
3469	seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
3470		   action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
3471		   action->track_data.var_str, track_data->track_val);
3472
3473	seq_puts(m, "\ttriggered by event with key: ");
3474	hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
3475	seq_putc(m, '\n');
3476}
3477#else
3478static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3479{
3480	return false;
3481}
3482static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3483				     struct tracing_map_elt *elt,
3484				     struct trace_buffer *buffer, void *rec,
3485				     struct ring_buffer_event *rbe, void *key,
3486				     struct action_data *data,
3487				     u64 *var_ref_vals) {}
3488static void track_data_snapshot_print(struct seq_file *m,
3489				      struct hist_trigger_data *hist_data) {}
3490#endif /* CONFIG_TRACER_SNAPSHOT */
3491
3492static void track_data_print(struct seq_file *m,
3493			     struct hist_trigger_data *hist_data,
3494			     struct tracing_map_elt *elt,
3495			     struct action_data *data)
3496{
3497	u64 track_val = get_track_val(hist_data, elt, data);
3498	unsigned int i, save_var_idx;
3499
3500	if (data->handler == HANDLER_ONMAX)
3501		seq_printf(m, "\n\tmax: %10llu", track_val);
3502	else if (data->handler == HANDLER_ONCHANGE)
3503		seq_printf(m, "\n\tchanged: %10llu", track_val);
3504
3505	if (data->action == ACTION_SNAPSHOT)
3506		return;
3507
3508	for (i = 0; i < hist_data->n_save_vars; i++) {
3509		struct hist_field *save_val = hist_data->save_vars[i]->val;
3510		struct hist_field *save_var = hist_data->save_vars[i]->var;
3511		u64 val;
3512
3513		save_var_idx = save_var->var.idx;
3514
3515		val = tracing_map_read_var(elt, save_var_idx);
3516
3517		if (save_val->flags & HIST_FIELD_FL_STRING) {
3518			seq_printf(m, "  %s: %-32s", save_var->var.name,
3519				   (char *)(uintptr_t)(val));
3520		} else
3521			seq_printf(m, "  %s: %10llu", save_var->var.name, val);
3522	}
3523}
3524
3525static void ontrack_action(struct hist_trigger_data *hist_data,
3526			   struct tracing_map_elt *elt,
3527			   struct trace_buffer *buffer, void *rec,
3528			   struct ring_buffer_event *rbe, void *key,
3529			   struct action_data *data, u64 *var_ref_vals)
3530{
3531	u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];
3532
3533	if (check_track_val(elt, data, var_val)) {
3534		save_track_val(hist_data, elt, data, var_val);
3535		save_track_data(hist_data, elt, buffer, rec, rbe,
3536				key, data, var_ref_vals);
3537	}
3538}
3539
3540static void action_data_destroy(struct action_data *data)
3541{
3542	unsigned int i;
3543
3544	lockdep_assert_held(&event_mutex);
3545
3546	kfree(data->action_name);
3547
3548	for (i = 0; i < data->n_params; i++)
3549		kfree(data->params[i]);
3550
3551	if (data->synth_event)
3552		data->synth_event->ref--;
3553
3554	kfree(data->synth_event_name);
3555
3556	kfree(data);
3557}
3558
3559static void track_data_destroy(struct hist_trigger_data *hist_data,
3560			       struct action_data *data)
3561{
3562	struct trace_event_file *file = hist_data->event_file;
3563
3564	destroy_hist_field(data->track_data.track_var, 0);
3565
3566	if (data->action == ACTION_SNAPSHOT) {
3567		struct track_data *track_data;
3568
3569		track_data = tracing_cond_snapshot_data(file->tr);
3570		if (track_data && track_data->hist_data == hist_data) {
3571			tracing_snapshot_cond_disable(file->tr);
3572			track_data_free(track_data);
3573		}
3574	}
3575
3576	kfree(data->track_data.var_str);
3577
3578	action_data_destroy(data);
3579}
3580
3581static int action_create(struct hist_trigger_data *hist_data,
3582			 struct action_data *data);
3583
3584static int track_data_create(struct hist_trigger_data *hist_data,
3585			     struct action_data *data)
3586{
3587	struct hist_field *var_field, *ref_field, *track_var = NULL;
3588	struct trace_event_file *file = hist_data->event_file;
3589	struct trace_array *tr = file->tr;
3590	char *track_data_var_str;
3591	int ret = 0;
3592
3593	track_data_var_str = data->track_data.var_str;
3594	if (track_data_var_str[0] != '$') {
3595		hist_err(tr, HIST_ERR_ONX_NOT_VAR, errpos(track_data_var_str));
3596		return -EINVAL;
3597	}
3598	track_data_var_str++;
3599
3600	var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
3601	if (!var_field) {
3602		hist_err(tr, HIST_ERR_ONX_VAR_NOT_FOUND, errpos(track_data_var_str));
3603		return -EINVAL;
3604	}
3605
3606	ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
3607	if (!ref_field)
3608		return -ENOMEM;
3609
3610	data->track_data.var_ref = ref_field;
3611
3612	if (data->handler == HANDLER_ONMAX)
3613		track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
3614	if (IS_ERR(track_var)) {
3615		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3616		ret = PTR_ERR(track_var);
3617		goto out;
3618	}
3619
3620	if (data->handler == HANDLER_ONCHANGE)
3621		track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
3622	if (IS_ERR(track_var)) {
3623		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3624		ret = PTR_ERR(track_var);
3625		goto out;
3626	}
3627	data->track_data.track_var = track_var;
3628
3629	ret = action_create(hist_data, data);
3630 out:
3631	return ret;
3632}
3633
3634static int parse_action_params(struct trace_array *tr, char *params,
3635			       struct action_data *data)
3636{
3637	char *param, *saved_param;
3638	bool first_param = true;
3639	int ret = 0;
3640
3641	while (params) {
3642		if (data->n_params >= SYNTH_FIELDS_MAX) {
3643			hist_err(tr, HIST_ERR_TOO_MANY_PARAMS, 0);
3644			ret = -EINVAL;
3645			goto out;
3646		}
3647
3648		param = strsep(&params, ",");
3649		if (!param) {
3650			hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, 0);
3651			ret = -EINVAL;
3652			goto out;
3653		}
3654
3655		param = strstrip(param);
3656		if (strlen(param) < 2) {
3657			hist_err(tr, HIST_ERR_INVALID_PARAM, errpos(param));
3658			ret = -EINVAL;
3659			goto out;
3660		}
3661
3662		saved_param = kstrdup(param, GFP_KERNEL);
3663		if (!saved_param) {
3664			ret = -ENOMEM;
3665			goto out;
3666		}
3667
3668		if (first_param && data->use_trace_keyword) {
3669			data->synth_event_name = saved_param;
3670			first_param = false;
3671			continue;
3672		}
3673		first_param = false;
3674
3675		data->params[data->n_params++] = saved_param;
3676	}
3677 out:
3678	return ret;
3679}
3680
3681static int action_parse(struct trace_array *tr, char *str, struct action_data *data,
3682			enum handler_id handler)
3683{
3684	char *action_name;
3685	int ret = 0;
3686
3687	strsep(&str, ".");
3688	if (!str) {
3689		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3690		ret = -EINVAL;
3691		goto out;
3692	}
3693
3694	action_name = strsep(&str, "(");
3695	if (!action_name || !str) {
3696		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3697		ret = -EINVAL;
3698		goto out;
3699	}
3700
3701	if (str_has_prefix(action_name, "save")) {
3702		char *params = strsep(&str, ")");
3703
3704		if (!params) {
3705			hist_err(tr, HIST_ERR_NO_SAVE_PARAMS, 0);
3706			ret = -EINVAL;
3707			goto out;
3708		}
3709
3710		ret = parse_action_params(tr, params, data);
3711		if (ret)
3712			goto out;
3713
3714		if (handler == HANDLER_ONMAX)
3715			data->track_data.check_val = check_track_val_max;
3716		else if (handler == HANDLER_ONCHANGE)
3717			data->track_data.check_val = check_track_val_changed;
3718		else {
3719			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3720			ret = -EINVAL;
3721			goto out;
3722		}
3723
3724		data->track_data.save_data = save_track_data_vars;
3725		data->fn = ontrack_action;
3726		data->action = ACTION_SAVE;
3727	} else if (str_has_prefix(action_name, "snapshot")) {
3728		char *params = strsep(&str, ")");
3729
3730		if (!str) {
3731			hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(params));
3732			ret = -EINVAL;
3733			goto out;
3734		}
3735
3736		if (handler == HANDLER_ONMAX)
3737			data->track_data.check_val = check_track_val_max;
3738		else if (handler == HANDLER_ONCHANGE)
3739			data->track_data.check_val = check_track_val_changed;
3740		else {
3741			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3742			ret = -EINVAL;
3743			goto out;
3744		}
3745
3746		data->track_data.save_data = save_track_data_snapshot;
3747		data->fn = ontrack_action;
3748		data->action = ACTION_SNAPSHOT;
3749	} else {
3750		char *params = strsep(&str, ")");
3751
3752		if (str_has_prefix(action_name, "trace"))
3753			data->use_trace_keyword = true;
3754
3755		if (params) {
3756			ret = parse_action_params(tr, params, data);
3757			if (ret)
3758				goto out;
3759		}
3760
3761		if (handler == HANDLER_ONMAX)
3762			data->track_data.check_val = check_track_val_max;
3763		else if (handler == HANDLER_ONCHANGE)
3764			data->track_data.check_val = check_track_val_changed;
3765
3766		if (handler != HANDLER_ONMATCH) {
3767			data->track_data.save_data = action_trace;
3768			data->fn = ontrack_action;
3769		} else
3770			data->fn = action_trace;
3771
3772		data->action = ACTION_TRACE;
3773	}
3774
3775	data->action_name = kstrdup(action_name, GFP_KERNEL);
3776	if (!data->action_name) {
3777		ret = -ENOMEM;
3778		goto out;
3779	}
3780
3781	data->handler = handler;
3782 out:
3783	return ret;
3784}
3785
3786static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
3787					    char *str, enum handler_id handler)
3788{
3789	struct action_data *data;
3790	int ret = -EINVAL;
3791	char *var_str;
3792
3793	data = kzalloc(sizeof(*data), GFP_KERNEL);
3794	if (!data)
3795		return ERR_PTR(-ENOMEM);
3796
3797	var_str = strsep(&str, ")");
3798	if (!var_str || !str) {
3799		ret = -EINVAL;
3800		goto free;
3801	}
3802
3803	data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
3804	if (!data->track_data.var_str) {
3805		ret = -ENOMEM;
3806		goto free;
3807	}
3808
3809	ret = action_parse(hist_data->event_file->tr, str, data, handler);
3810	if (ret)
3811		goto free;
3812 out:
3813	return data;
3814 free:
3815	track_data_destroy(hist_data, data);
3816	data = ERR_PTR(ret);
3817	goto out;
3818}
3819
3820static void onmatch_destroy(struct action_data *data)
3821{
3822	kfree(data->match_data.event);
3823	kfree(data->match_data.event_system);
3824
3825	action_data_destroy(data);
3826}
3827
3828static void destroy_field_var(struct field_var *field_var)
3829{
3830	if (!field_var)
3831		return;
3832
3833	destroy_hist_field(field_var->var, 0);
3834	destroy_hist_field(field_var->val, 0);
3835
3836	kfree(field_var);
3837}
3838
3839static void destroy_field_vars(struct hist_trigger_data *hist_data)
3840{
3841	unsigned int i;
3842
3843	for (i = 0; i < hist_data->n_field_vars; i++)
3844		destroy_field_var(hist_data->field_vars[i]);
3845
3846	for (i = 0; i < hist_data->n_save_vars; i++)
3847		destroy_field_var(hist_data->save_vars[i]);
3848}
3849
3850static void save_field_var(struct hist_trigger_data *hist_data,
3851			   struct field_var *field_var)
3852{
3853	hist_data->field_vars[hist_data->n_field_vars++] = field_var;
3854
3855	/* Stack traces are saved in the string storage too */
3856	if (field_var->val->flags & (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
3857		hist_data->n_field_var_str++;
3858}
3859
3860
3861static int check_synth_field(struct synth_event *event,
3862			     struct hist_field *hist_field,
3863			     unsigned int field_pos)
3864{
3865	struct synth_field *field;
3866
3867	if (field_pos >= event->n_fields)
3868		return -EINVAL;
3869
3870	field = event->fields[field_pos];
3871
3872	/*
3873	 * A dynamic string synth field can accept static or
3874	 * dynamic. A static string synth field can only accept a
3875	 * same-sized static string, which is checked for later.
3876	 */
3877	if (strstr(hist_field->type, "char[") && field->is_string
3878	    && field->is_dynamic)
3879		return 0;
3880
3881	if (strstr(hist_field->type, "long[") && field->is_stack)
3882		return 0;
3883
3884	if (strcmp(field->type, hist_field->type) != 0) {
3885		if (field->size != hist_field->size ||
3886		    (!field->is_string && field->is_signed != hist_field->is_signed))
3887			return -EINVAL;
3888	}
3889
3890	return 0;
3891}
3892
3893static struct hist_field *
3894trace_action_find_var(struct hist_trigger_data *hist_data,
3895		      struct action_data *data,
3896		      char *system, char *event, char *var)
3897{
3898	struct trace_array *tr = hist_data->event_file->tr;
3899	struct hist_field *hist_field;
3900
3901	var++; /* skip '$' */
3902
3903	hist_field = find_target_event_var(hist_data, system, event, var);
3904	if (!hist_field) {
3905		if (!system && data->handler == HANDLER_ONMATCH) {
3906			system = data->match_data.event_system;
3907			event = data->match_data.event;
3908		}
3909
3910		hist_field = find_event_var(hist_data, system, event, var);
3911	}
3912
3913	if (!hist_field)
3914		hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, errpos(var));
3915
3916	return hist_field;
3917}
3918
3919static struct hist_field *
3920trace_action_create_field_var(struct hist_trigger_data *hist_data,
3921			      struct action_data *data, char *system,
3922			      char *event, char *var)
3923{
3924	struct hist_field *hist_field = NULL;
3925	struct field_var *field_var;
3926
3927	/*
3928	 * First try to create a field var on the target event (the
3929	 * currently being defined).  This will create a variable for
3930	 * unqualified fields on the target event, or if qualified,
3931	 * target fields that have qualified names matching the target.
3932	 */
3933	field_var = create_target_field_var(hist_data, system, event, var);
3934
3935	if (field_var && !IS_ERR(field_var)) {
3936		save_field_var(hist_data, field_var);
3937		hist_field = field_var->var;
3938	} else {
3939		field_var = NULL;
3940		/*
3941		 * If no explicit system.event is specified, default to
3942		 * looking for fields on the onmatch(system.event.xxx)
3943		 * event.
3944		 */
3945		if (!system && data->handler == HANDLER_ONMATCH) {
3946			system = data->match_data.event_system;
3947			event = data->match_data.event;
3948		}
3949
3950		if (!event)
3951			goto free;
3952		/*
3953		 * At this point, we're looking at a field on another
3954		 * event.  Because we can't modify a hist trigger on
3955		 * another event to add a variable for a field, we need
3956		 * to create a new trigger on that event and create the
3957		 * variable at the same time.
3958		 */
3959		hist_field = create_field_var_hist(hist_data, system, event, var);
3960		if (IS_ERR(hist_field))
3961			goto free;
3962	}
3963 out:
3964	return hist_field;
3965 free:
3966	destroy_field_var(field_var);
3967	hist_field = NULL;
3968	goto out;
3969}
3970
3971static int trace_action_create(struct hist_trigger_data *hist_data,
3972			       struct action_data *data)
3973{
3974	struct trace_array *tr = hist_data->event_file->tr;
3975	char *event_name, *param, *system = NULL;
3976	struct hist_field *hist_field, *var_ref;
3977	unsigned int i;
3978	unsigned int field_pos = 0;
3979	struct synth_event *event;
3980	char *synth_event_name;
3981	int var_ref_idx, ret = 0;
3982
3983	lockdep_assert_held(&event_mutex);
3984
3985	/* Sanity check to avoid out-of-bound write on 'data->var_ref_idx' */
3986	if (data->n_params > SYNTH_FIELDS_MAX)
3987		return -EINVAL;
3988
3989	if (data->use_trace_keyword)
3990		synth_event_name = data->synth_event_name;
3991	else
3992		synth_event_name = data->action_name;
3993
3994	event = find_synth_event(synth_event_name);
3995	if (!event) {
3996		hist_err(tr, HIST_ERR_SYNTH_EVENT_NOT_FOUND, errpos(synth_event_name));
3997		return -EINVAL;
3998	}
3999
4000	event->ref++;
4001
4002	for (i = 0; i < data->n_params; i++) {
4003		char *p;
4004
4005		p = param = kstrdup(data->params[i], GFP_KERNEL);
4006		if (!param) {
4007			ret = -ENOMEM;
4008			goto err;
4009		}
4010
4011		system = strsep(&param, ".");
4012		if (!param) {
4013			param = (char *)system;
4014			system = event_name = NULL;
4015		} else {
4016			event_name = strsep(&param, ".");
4017			if (!param) {
4018				kfree(p);
4019				ret = -EINVAL;
4020				goto err;
4021			}
4022		}
4023
4024		if (param[0] == '$')
4025			hist_field = trace_action_find_var(hist_data, data,
4026							   system, event_name,
4027							   param);
4028		else
4029			hist_field = trace_action_create_field_var(hist_data,
4030								   data,
4031								   system,
4032								   event_name,
4033								   param);
4034
4035		if (!hist_field) {
4036			kfree(p);
4037			ret = -EINVAL;
4038			goto err;
4039		}
4040
4041		if (check_synth_field(event, hist_field, field_pos) == 0) {
4042			var_ref = create_var_ref(hist_data, hist_field,
4043						 system, event_name);
4044			if (!var_ref) {
4045				kfree(p);
4046				ret = -ENOMEM;
4047				goto err;
4048			}
4049
4050			var_ref_idx = find_var_ref_idx(hist_data, var_ref);
4051			if (WARN_ON(var_ref_idx < 0)) {
4052				kfree(p);
4053				ret = var_ref_idx;
4054				goto err;
4055			}
4056
4057			data->var_ref_idx[i] = var_ref_idx;
4058
4059			field_pos++;
4060			kfree(p);
4061			continue;
4062		}
4063
4064		hist_err(tr, HIST_ERR_SYNTH_TYPE_MISMATCH, errpos(param));
4065		kfree(p);
4066		ret = -EINVAL;
4067		goto err;
4068	}
4069
4070	if (field_pos != event->n_fields) {
4071		hist_err(tr, HIST_ERR_SYNTH_COUNT_MISMATCH, errpos(event->name));
4072		ret = -EINVAL;
4073		goto err;
4074	}
4075
4076	data->synth_event = event;
4077 out:
4078	return ret;
4079 err:
4080	event->ref--;
4081
4082	goto out;
4083}
4084
4085static int action_create(struct hist_trigger_data *hist_data,
4086			 struct action_data *data)
4087{
4088	struct trace_event_file *file = hist_data->event_file;
4089	struct trace_array *tr = file->tr;
4090	struct track_data *track_data;
4091	struct field_var *field_var;
4092	unsigned int i;
4093	char *param;
4094	int ret = 0;
4095
4096	if (data->action == ACTION_TRACE)
4097		return trace_action_create(hist_data, data);
4098
4099	if (data->action == ACTION_SNAPSHOT) {
4100		track_data = track_data_alloc(hist_data->key_size, data, hist_data);
4101		if (IS_ERR(track_data)) {
4102			ret = PTR_ERR(track_data);
4103			goto out;
4104		}
4105
4106		ret = tracing_snapshot_cond_enable(file->tr, track_data,
4107						   cond_snapshot_update);
4108		if (ret)
4109			track_data_free(track_data);
4110
4111		goto out;
4112	}
4113
4114	if (data->action == ACTION_SAVE) {
4115		if (hist_data->n_save_vars) {
4116			ret = -EEXIST;
4117			hist_err(tr, HIST_ERR_TOO_MANY_SAVE_ACTIONS, 0);
4118			goto out;
4119		}
4120
4121		for (i = 0; i < data->n_params; i++) {
4122			param = kstrdup(data->params[i], GFP_KERNEL);
4123			if (!param) {
4124				ret = -ENOMEM;
4125				goto out;
4126			}
4127
4128			field_var = create_target_field_var(hist_data, NULL, NULL, param);
4129			if (IS_ERR(field_var)) {
4130				hist_err(tr, HIST_ERR_FIELD_VAR_CREATE_FAIL,
4131					 errpos(param));
4132				ret = PTR_ERR(field_var);
4133				kfree(param);
4134				goto out;
4135			}
4136
4137			hist_data->save_vars[hist_data->n_save_vars++] = field_var;
4138			if (field_var->val->flags &
4139			    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
4140				hist_data->n_save_var_str++;
4141			kfree(param);
4142		}
4143	}
4144 out:
4145	return ret;
4146}
4147
4148static int onmatch_create(struct hist_trigger_data *hist_data,
4149			  struct action_data *data)
4150{
4151	return action_create(hist_data, data);
4152}
4153
4154static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
4155{
4156	char *match_event, *match_event_system;
4157	struct action_data *data;
4158	int ret = -EINVAL;
4159
4160	data = kzalloc(sizeof(*data), GFP_KERNEL);
4161	if (!data)
4162		return ERR_PTR(-ENOMEM);
4163
4164	match_event = strsep(&str, ")");
4165	if (!match_event || !str) {
4166		hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(match_event));
4167		goto free;
4168	}
4169
4170	match_event_system = strsep(&match_event, ".");
4171	if (!match_event) {
4172		hist_err(tr, HIST_ERR_SUBSYS_NOT_FOUND, errpos(match_event_system));
4173		goto free;
4174	}
4175
4176	if (IS_ERR(event_file(tr, match_event_system, match_event))) {
4177		hist_err(tr, HIST_ERR_INVALID_SUBSYS_EVENT, errpos(match_event));
4178		goto free;
4179	}
4180
4181	data->match_data.event = kstrdup(match_event, GFP_KERNEL);
4182	if (!data->match_data.event) {
4183		ret = -ENOMEM;
4184		goto free;
4185	}
4186
4187	data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
4188	if (!data->match_data.event_system) {
4189		ret = -ENOMEM;
4190		goto free;
4191	}
4192
4193	ret = action_parse(tr, str, data, HANDLER_ONMATCH);
4194	if (ret)
4195		goto free;
4196 out:
4197	return data;
4198 free:
4199	onmatch_destroy(data);
4200	data = ERR_PTR(ret);
4201	goto out;
4202}
4203
4204static int create_hitcount_val(struct hist_trigger_data *hist_data)
4205{
4206	hist_data->fields[HITCOUNT_IDX] =
4207		create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
4208	if (!hist_data->fields[HITCOUNT_IDX])
4209		return -ENOMEM;
4210
4211	hist_data->n_vals++;
4212	hist_data->n_fields++;
4213
4214	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
4215		return -EINVAL;
4216
4217	return 0;
4218}
4219
4220static int __create_val_field(struct hist_trigger_data *hist_data,
4221			      unsigned int val_idx,
4222			      struct trace_event_file *file,
4223			      char *var_name, char *field_str,
4224			      unsigned long flags)
4225{
4226	struct hist_field *hist_field;
4227	int ret = 0, n_subexprs = 0;
4228
4229	hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs);
4230	if (IS_ERR(hist_field)) {
4231		ret = PTR_ERR(hist_field);
4232		goto out;
4233	}
4234
4235	/* values and variables should not have some modifiers */
4236	if (hist_field->flags & HIST_FIELD_FL_VAR) {
4237		/* Variable */
4238		if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
4239					 HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2))
4240			goto err;
4241	} else {
4242		/* Value */
4243		if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
4244					 HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 |
4245					 HIST_FIELD_FL_SYM | HIST_FIELD_FL_SYM_OFFSET |
4246					 HIST_FIELD_FL_SYSCALL | HIST_FIELD_FL_STACKTRACE))
4247			goto err;
4248	}
4249
4250	hist_data->fields[val_idx] = hist_field;
4251
4252	++hist_data->n_vals;
4253	++hist_data->n_fields;
4254
4255	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4256		ret = -EINVAL;
4257 out:
4258	return ret;
4259 err:
4260	hist_err(file->tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
4261	return -EINVAL;
4262}
4263
4264static int create_val_field(struct hist_trigger_data *hist_data,
4265			    unsigned int val_idx,
4266			    struct trace_event_file *file,
4267			    char *field_str)
4268{
4269	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
4270		return -EINVAL;
4271
4272	return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
4273}
4274
4275static const char no_comm[] = "(no comm)";
4276
4277static u64 hist_field_execname(struct hist_field *hist_field,
4278			       struct tracing_map_elt *elt,
4279			       struct trace_buffer *buffer,
4280			       struct ring_buffer_event *rbe,
4281			       void *event)
4282{
4283	struct hist_elt_data *elt_data;
4284
4285	if (WARN_ON_ONCE(!elt))
4286		return (u64)(unsigned long)no_comm;
4287
4288	elt_data = elt->private_data;
4289
4290	if (WARN_ON_ONCE(!elt_data->comm))
4291		return (u64)(unsigned long)no_comm;
4292
4293	return (u64)(unsigned long)(elt_data->comm);
4294}
4295
4296static u64 hist_field_stack(struct hist_field *hist_field,
4297			    struct tracing_map_elt *elt,
4298			    struct trace_buffer *buffer,
4299			    struct ring_buffer_event *rbe,
4300			    void *event)
4301{
4302	u32 str_item = *(u32 *)(event + hist_field->field->offset);
4303	int str_loc = str_item & 0xffff;
4304	char *addr = (char *)(event + str_loc);
4305
4306	return (u64)(unsigned long)addr;
4307}
4308
4309static u64 hist_fn_call(struct hist_field *hist_field,
4310			struct tracing_map_elt *elt,
4311			struct trace_buffer *buffer,
4312			struct ring_buffer_event *rbe,
4313			void *event)
4314{
4315	switch (hist_field->fn_num) {
4316	case HIST_FIELD_FN_VAR_REF:
4317		return hist_field_var_ref(hist_field, elt, buffer, rbe, event);
4318	case HIST_FIELD_FN_COUNTER:
4319		return hist_field_counter(hist_field, elt, buffer, rbe, event);
4320	case HIST_FIELD_FN_CONST:
4321		return hist_field_const(hist_field, elt, buffer, rbe, event);
4322	case HIST_FIELD_FN_LOG2:
4323		return hist_field_log2(hist_field, elt, buffer, rbe, event);
4324	case HIST_FIELD_FN_BUCKET:
4325		return hist_field_bucket(hist_field, elt, buffer, rbe, event);
4326	case HIST_FIELD_FN_TIMESTAMP:
4327		return hist_field_timestamp(hist_field, elt, buffer, rbe, event);
4328	case HIST_FIELD_FN_CPU:
4329		return hist_field_cpu(hist_field, elt, buffer, rbe, event);
4330	case HIST_FIELD_FN_STRING:
4331		return hist_field_string(hist_field, elt, buffer, rbe, event);
4332	case HIST_FIELD_FN_DYNSTRING:
4333		return hist_field_dynstring(hist_field, elt, buffer, rbe, event);
4334	case HIST_FIELD_FN_RELDYNSTRING:
4335		return hist_field_reldynstring(hist_field, elt, buffer, rbe, event);
4336	case HIST_FIELD_FN_PSTRING:
4337		return hist_field_pstring(hist_field, elt, buffer, rbe, event);
4338	case HIST_FIELD_FN_S64:
4339		return hist_field_s64(hist_field, elt, buffer, rbe, event);
4340	case HIST_FIELD_FN_U64:
4341		return hist_field_u64(hist_field, elt, buffer, rbe, event);
4342	case HIST_FIELD_FN_S32:
4343		return hist_field_s32(hist_field, elt, buffer, rbe, event);
4344	case HIST_FIELD_FN_U32:
4345		return hist_field_u32(hist_field, elt, buffer, rbe, event);
4346	case HIST_FIELD_FN_S16:
4347		return hist_field_s16(hist_field, elt, buffer, rbe, event);
4348	case HIST_FIELD_FN_U16:
4349		return hist_field_u16(hist_field, elt, buffer, rbe, event);
4350	case HIST_FIELD_FN_S8:
4351		return hist_field_s8(hist_field, elt, buffer, rbe, event);
4352	case HIST_FIELD_FN_U8:
4353		return hist_field_u8(hist_field, elt, buffer, rbe, event);
4354	case HIST_FIELD_FN_UMINUS:
4355		return hist_field_unary_minus(hist_field, elt, buffer, rbe, event);
4356	case HIST_FIELD_FN_MINUS:
4357		return hist_field_minus(hist_field, elt, buffer, rbe, event);
4358	case HIST_FIELD_FN_PLUS:
4359		return hist_field_plus(hist_field, elt, buffer, rbe, event);
4360	case HIST_FIELD_FN_DIV:
4361		return hist_field_div(hist_field, elt, buffer, rbe, event);
4362	case HIST_FIELD_FN_MULT:
4363		return hist_field_mult(hist_field, elt, buffer, rbe, event);
4364	case HIST_FIELD_FN_DIV_POWER2:
4365		return div_by_power_of_two(hist_field, elt, buffer, rbe, event);
4366	case HIST_FIELD_FN_DIV_NOT_POWER2:
4367		return div_by_not_power_of_two(hist_field, elt, buffer, rbe, event);
4368	case HIST_FIELD_FN_DIV_MULT_SHIFT:
4369		return div_by_mult_and_shift(hist_field, elt, buffer, rbe, event);
4370	case HIST_FIELD_FN_EXECNAME:
4371		return hist_field_execname(hist_field, elt, buffer, rbe, event);
4372	case HIST_FIELD_FN_STACK:
4373		return hist_field_stack(hist_field, elt, buffer, rbe, event);
4374	default:
4375		return 0;
4376	}
4377}
4378
4379/* Convert a var that points to common_pid.execname to a string */
4380static void update_var_execname(struct hist_field *hist_field)
4381{
4382	hist_field->flags = HIST_FIELD_FL_STRING | HIST_FIELD_FL_VAR |
4383		HIST_FIELD_FL_EXECNAME;
4384	hist_field->size = MAX_FILTER_STR_VAL;
4385	hist_field->is_signed = 0;
4386
4387	kfree_const(hist_field->type);
4388	hist_field->type = "char[]";
4389
4390	hist_field->fn_num = HIST_FIELD_FN_EXECNAME;
4391}
4392
4393static int create_var_field(struct hist_trigger_data *hist_data,
4394			    unsigned int val_idx,
4395			    struct trace_event_file *file,
4396			    char *var_name, char *expr_str)
4397{
4398	struct trace_array *tr = hist_data->event_file->tr;
4399	unsigned long flags = 0;
4400	int ret;
4401
4402	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4403		return -EINVAL;
4404
4405	if (find_var(hist_data, file, var_name) && !hist_data->remove) {
4406		hist_err(tr, HIST_ERR_DUPLICATE_VAR, errpos(var_name));
4407		return -EINVAL;
4408	}
4409
4410	flags |= HIST_FIELD_FL_VAR;
4411	hist_data->n_vars++;
4412	if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
4413		return -EINVAL;
4414
4415	ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
4416
4417	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
4418		update_var_execname(hist_data->fields[val_idx]);
4419
4420	if (!ret && hist_data->fields[val_idx]->flags &
4421	    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
4422		hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
4423
4424	return ret;
4425}
4426
4427static int create_val_fields(struct hist_trigger_data *hist_data,
4428			     struct trace_event_file *file)
4429{
4430	unsigned int i, j = 1, n_hitcount = 0;
4431	char *fields_str, *field_str;
4432	int ret;
4433
4434	ret = create_hitcount_val(hist_data);
4435	if (ret)
4436		goto out;
4437
4438	fields_str = hist_data->attrs->vals_str;
4439	if (!fields_str)
4440		goto out;
4441
4442	for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
4443		     j < TRACING_MAP_VALS_MAX; i++) {
4444		field_str = strsep(&fields_str, ",");
4445		if (!field_str)
4446			break;
4447
4448		if (strcmp(field_str, "hitcount") == 0) {
4449			if (!n_hitcount++)
4450				continue;
4451		}
4452
4453		ret = create_val_field(hist_data, j++, file, field_str);
4454		if (ret)
4455			goto out;
4456	}
4457
4458	if (fields_str && (strcmp(fields_str, "hitcount") != 0))
4459		ret = -EINVAL;
4460 out:
4461	/* There is only raw hitcount but nohitcount suppresses it. */
4462	if (j == 1 && hist_data->attrs->no_hitcount) {
4463		hist_err(hist_data->event_file->tr, HIST_ERR_NEED_NOHC_VAL, 0);
4464		ret = -ENOENT;
4465	}
4466
4467	return ret;
4468}
4469
4470static int create_key_field(struct hist_trigger_data *hist_data,
4471			    unsigned int key_idx,
4472			    unsigned int key_offset,
4473			    struct trace_event_file *file,
4474			    char *field_str)
4475{
4476	struct trace_array *tr = hist_data->event_file->tr;
4477	struct hist_field *hist_field = NULL;
4478	unsigned long flags = 0;
4479	unsigned int key_size;
4480	int ret = 0, n_subexprs = 0;
4481
4482	if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
4483		return -EINVAL;
4484
4485	flags |= HIST_FIELD_FL_KEY;
4486
4487	if (strcmp(field_str, "stacktrace") == 0) {
4488		flags |= HIST_FIELD_FL_STACKTRACE;
4489		key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
4490		hist_field = create_hist_field(hist_data, NULL, flags, NULL);
4491	} else {
4492		hist_field = parse_expr(hist_data, file, field_str, flags,
4493					NULL, &n_subexprs);
4494		if (IS_ERR(hist_field)) {
4495			ret = PTR_ERR(hist_field);
4496			goto out;
4497		}
4498
4499		if (field_has_hist_vars(hist_field, 0))	{
4500			hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
4501			destroy_hist_field(hist_field, 0);
4502			ret = -EINVAL;
4503			goto out;
4504		}
4505
4506		key_size = hist_field->size;
4507	}
4508
4509	hist_data->fields[key_idx] = hist_field;
4510
4511	key_size = ALIGN(key_size, sizeof(u64));
4512	hist_data->fields[key_idx]->size = key_size;
4513	hist_data->fields[key_idx]->offset = key_offset;
4514
4515	hist_data->key_size += key_size;
4516
4517	if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
4518		ret = -EINVAL;
4519		goto out;
4520	}
4521
4522	hist_data->n_keys++;
4523	hist_data->n_fields++;
4524
4525	if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
4526		return -EINVAL;
4527
4528	ret = key_size;
4529 out:
4530	return ret;
4531}
4532
4533static int create_key_fields(struct hist_trigger_data *hist_data,
4534			     struct trace_event_file *file)
4535{
4536	unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
4537	char *fields_str, *field_str;
4538	int ret = -EINVAL;
4539
4540	fields_str = hist_data->attrs->keys_str;
4541	if (!fields_str)
4542		goto out;
4543
4544	for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
4545		field_str = strsep(&fields_str, ",");
4546		if (!field_str)
4547			break;
4548		ret = create_key_field(hist_data, i, key_offset,
4549				       file, field_str);
4550		if (ret < 0)
4551			goto out;
4552		key_offset += ret;
4553	}
4554	if (fields_str) {
4555		ret = -EINVAL;
4556		goto out;
4557	}
4558	ret = 0;
4559 out:
4560	return ret;
4561}
4562
4563static int create_var_fields(struct hist_trigger_data *hist_data,
4564			     struct trace_event_file *file)
4565{
4566	unsigned int i, j = hist_data->n_vals;
4567	int ret = 0;
4568
4569	unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
4570
4571	for (i = 0; i < n_vars; i++) {
4572		char *var_name = hist_data->attrs->var_defs.name[i];
4573		char *expr = hist_data->attrs->var_defs.expr[i];
4574
4575		ret = create_var_field(hist_data, j++, file, var_name, expr);
4576		if (ret)
4577			goto out;
4578	}
4579 out:
4580	return ret;
4581}
4582
4583static void free_var_defs(struct hist_trigger_data *hist_data)
4584{
4585	unsigned int i;
4586
4587	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
4588		kfree(hist_data->attrs->var_defs.name[i]);
4589		kfree(hist_data->attrs->var_defs.expr[i]);
4590	}
4591
4592	hist_data->attrs->var_defs.n_vars = 0;
4593}
4594
4595static int parse_var_defs(struct hist_trigger_data *hist_data)
4596{
4597	struct trace_array *tr = hist_data->event_file->tr;
4598	char *s, *str, *var_name, *field_str;
4599	unsigned int i, j, n_vars = 0;
4600	int ret = 0;
4601
4602	for (i = 0; i < hist_data->attrs->n_assignments; i++) {
4603		str = hist_data->attrs->assignment_str[i];
4604		for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
4605			field_str = strsep(&str, ",");
4606			if (!field_str)
4607				break;
4608
4609			var_name = strsep(&field_str, "=");
4610			if (!var_name || !field_str) {
4611				hist_err(tr, HIST_ERR_MALFORMED_ASSIGNMENT,
4612					 errpos(var_name));
4613				ret = -EINVAL;
4614				goto free;
4615			}
4616
4617			if (n_vars == TRACING_MAP_VARS_MAX) {
4618				hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(var_name));
4619				ret = -EINVAL;
4620				goto free;
4621			}
4622
4623			s = kstrdup(var_name, GFP_KERNEL);
4624			if (!s) {
4625				ret = -ENOMEM;
4626				goto free;
4627			}
4628			hist_data->attrs->var_defs.name[n_vars] = s;
4629
4630			s = kstrdup(field_str, GFP_KERNEL);
4631			if (!s) {
4632				kfree(hist_data->attrs->var_defs.name[n_vars]);
4633				hist_data->attrs->var_defs.name[n_vars] = NULL;
4634				ret = -ENOMEM;
4635				goto free;
4636			}
4637			hist_data->attrs->var_defs.expr[n_vars++] = s;
4638
4639			hist_data->attrs->var_defs.n_vars = n_vars;
4640		}
4641	}
4642
4643	return ret;
4644 free:
4645	free_var_defs(hist_data);
4646
4647	return ret;
4648}
4649
4650static int create_hist_fields(struct hist_trigger_data *hist_data,
4651			      struct trace_event_file *file)
4652{
4653	int ret;
4654
4655	ret = parse_var_defs(hist_data);
4656	if (ret)
4657		return ret;
4658
4659	ret = create_val_fields(hist_data, file);
4660	if (ret)
4661		goto out;
4662
4663	ret = create_var_fields(hist_data, file);
4664	if (ret)
4665		goto out;
4666
4667	ret = create_key_fields(hist_data, file);
4668
4669 out:
4670	free_var_defs(hist_data);
4671
4672	return ret;
4673}
4674
4675static int is_descending(struct trace_array *tr, const char *str)
4676{
4677	if (!str)
4678		return 0;
4679
4680	if (strcmp(str, "descending") == 0)
4681		return 1;
4682
4683	if (strcmp(str, "ascending") == 0)
4684		return 0;
4685
4686	hist_err(tr, HIST_ERR_INVALID_SORT_MODIFIER, errpos((char *)str));
4687
4688	return -EINVAL;
4689}
4690
4691static int create_sort_keys(struct hist_trigger_data *hist_data)
4692{
4693	struct trace_array *tr = hist_data->event_file->tr;
4694	char *fields_str = hist_data->attrs->sort_key_str;
4695	struct tracing_map_sort_key *sort_key;
4696	int descending, ret = 0;
4697	unsigned int i, j, k;
4698
4699	hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
4700
4701	if (!fields_str)
4702		goto out;
4703
4704	for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
4705		struct hist_field *hist_field;
4706		char *field_str, *field_name;
4707		const char *test_name;
4708
4709		sort_key = &hist_data->sort_keys[i];
4710
4711		field_str = strsep(&fields_str, ",");
4712		if (!field_str)
4713			break;
4714
4715		if (!*field_str) {
4716			ret = -EINVAL;
4717			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4718			break;
4719		}
4720
4721		if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
4722			hist_err(tr, HIST_ERR_TOO_MANY_SORT_FIELDS, errpos("sort="));
4723			ret = -EINVAL;
4724			break;
4725		}
4726
4727		field_name = strsep(&field_str, ".");
4728		if (!field_name || !*field_name) {
4729			ret = -EINVAL;
4730			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4731			break;
4732		}
4733
4734		if (strcmp(field_name, "hitcount") == 0) {
4735			descending = is_descending(tr, field_str);
4736			if (descending < 0) {
4737				ret = descending;
4738				break;
4739			}
4740			sort_key->descending = descending;
4741			continue;
4742		}
4743
4744		for (j = 1, k = 1; j < hist_data->n_fields; j++) {
4745			unsigned int idx;
4746
4747			hist_field = hist_data->fields[j];
4748			if (hist_field->flags & HIST_FIELD_FL_VAR)
4749				continue;
4750
4751			idx = k++;
4752
4753			test_name = hist_field_name(hist_field, 0);
4754
4755			if (strcmp(field_name, test_name) == 0) {
4756				sort_key->field_idx = idx;
4757				descending = is_descending(tr, field_str);
4758				if (descending < 0) {
4759					ret = descending;
4760					goto out;
4761				}
4762				sort_key->descending = descending;
4763				break;
4764			}
4765		}
4766		if (j == hist_data->n_fields) {
4767			ret = -EINVAL;
4768			hist_err(tr, HIST_ERR_INVALID_SORT_FIELD, errpos(field_name));
4769			break;
4770		}
4771	}
4772
4773	hist_data->n_sort_keys = i;
4774 out:
4775	return ret;
4776}
4777
4778static void destroy_actions(struct hist_trigger_data *hist_data)
4779{
4780	unsigned int i;
4781
4782	for (i = 0; i < hist_data->n_actions; i++) {
4783		struct action_data *data = hist_data->actions[i];
4784
4785		if (data->handler == HANDLER_ONMATCH)
4786			onmatch_destroy(data);
4787		else if (data->handler == HANDLER_ONMAX ||
4788			 data->handler == HANDLER_ONCHANGE)
4789			track_data_destroy(hist_data, data);
4790		else
4791			kfree(data);
4792	}
4793}
4794
4795static int parse_actions(struct hist_trigger_data *hist_data)
4796{
4797	struct trace_array *tr = hist_data->event_file->tr;
4798	struct action_data *data;
4799	unsigned int i;
4800	int ret = 0;
4801	char *str;
4802	int len;
4803
4804	for (i = 0; i < hist_data->attrs->n_actions; i++) {
4805		enum handler_id hid = 0;
4806		char *action_str;
4807
4808		str = hist_data->attrs->action_str[i];
4809
4810		if ((len = str_has_prefix(str, "onmatch(")))
4811			hid = HANDLER_ONMATCH;
4812		else if ((len = str_has_prefix(str, "onmax(")))
4813			hid = HANDLER_ONMAX;
4814		else if ((len = str_has_prefix(str, "onchange(")))
4815			hid = HANDLER_ONCHANGE;
4816
4817		action_str = str + len;
4818
4819		switch (hid) {
4820		case HANDLER_ONMATCH:
4821			data = onmatch_parse(tr, action_str);
4822			break;
4823		case HANDLER_ONMAX:
4824		case HANDLER_ONCHANGE:
4825			data = track_data_parse(hist_data, action_str, hid);
4826			break;
4827		default:
4828			data = ERR_PTR(-EINVAL);
4829			break;
4830		}
4831
4832		if (IS_ERR(data)) {
4833			ret = PTR_ERR(data);
4834			break;
4835		}
4836
4837		hist_data->actions[hist_data->n_actions++] = data;
4838	}
4839
4840	return ret;
4841}
4842
4843static int create_actions(struct hist_trigger_data *hist_data)
4844{
4845	struct action_data *data;
4846	unsigned int i;
4847	int ret = 0;
4848
4849	for (i = 0; i < hist_data->attrs->n_actions; i++) {
4850		data = hist_data->actions[i];
4851
4852		if (data->handler == HANDLER_ONMATCH) {
4853			ret = onmatch_create(hist_data, data);
4854			if (ret)
4855				break;
4856		} else if (data->handler == HANDLER_ONMAX ||
4857			   data->handler == HANDLER_ONCHANGE) {
4858			ret = track_data_create(hist_data, data);
4859			if (ret)
4860				break;
4861		} else {
4862			ret = -EINVAL;
4863			break;
4864		}
4865	}
4866
4867	return ret;
4868}
4869
4870static void print_actions(struct seq_file *m,
4871			  struct hist_trigger_data *hist_data,
4872			  struct tracing_map_elt *elt)
4873{
4874	unsigned int i;
4875
4876	for (i = 0; i < hist_data->n_actions; i++) {
4877		struct action_data *data = hist_data->actions[i];
4878
4879		if (data->action == ACTION_SNAPSHOT)
4880			continue;
4881
4882		if (data->handler == HANDLER_ONMAX ||
4883		    data->handler == HANDLER_ONCHANGE)
4884			track_data_print(m, hist_data, elt, data);
4885	}
4886}
4887
4888static void print_action_spec(struct seq_file *m,
4889			      struct hist_trigger_data *hist_data,
4890			      struct action_data *data)
4891{
4892	unsigned int i;
4893
4894	if (data->action == ACTION_SAVE) {
4895		for (i = 0; i < hist_data->n_save_vars; i++) {
4896			seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
4897			if (i < hist_data->n_save_vars - 1)
4898				seq_puts(m, ",");
4899		}
4900	} else if (data->action == ACTION_TRACE) {
4901		if (data->use_trace_keyword)
4902			seq_printf(m, "%s", data->synth_event_name);
4903		for (i = 0; i < data->n_params; i++) {
4904			if (i || data->use_trace_keyword)
4905				seq_puts(m, ",");
4906			seq_printf(m, "%s", data->params[i]);
4907		}
4908	}
4909}
4910
4911static void print_track_data_spec(struct seq_file *m,
4912				  struct hist_trigger_data *hist_data,
4913				  struct action_data *data)
4914{
4915	if (data->handler == HANDLER_ONMAX)
4916		seq_puts(m, ":onmax(");
4917	else if (data->handler == HANDLER_ONCHANGE)
4918		seq_puts(m, ":onchange(");
4919	seq_printf(m, "%s", data->track_data.var_str);
4920	seq_printf(m, ").%s(", data->action_name);
4921
4922	print_action_spec(m, hist_data, data);
4923
4924	seq_puts(m, ")");
4925}
4926
4927static void print_onmatch_spec(struct seq_file *m,
4928			       struct hist_trigger_data *hist_data,
4929			       struct action_data *data)
4930{
4931	seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
4932		   data->match_data.event);
4933
4934	seq_printf(m, "%s(", data->action_name);
4935
4936	print_action_spec(m, hist_data, data);
4937
4938	seq_puts(m, ")");
4939}
4940
4941static bool actions_match(struct hist_trigger_data *hist_data,
4942			  struct hist_trigger_data *hist_data_test)
4943{
4944	unsigned int i, j;
4945
4946	if (hist_data->n_actions != hist_data_test->n_actions)
4947		return false;
4948
4949	for (i = 0; i < hist_data->n_actions; i++) {
4950		struct action_data *data = hist_data->actions[i];
4951		struct action_data *data_test = hist_data_test->actions[i];
4952		char *action_name, *action_name_test;
4953
4954		if (data->handler != data_test->handler)
4955			return false;
4956		if (data->action != data_test->action)
4957			return false;
4958
4959		if (data->n_params != data_test->n_params)
4960			return false;
4961
4962		for (j = 0; j < data->n_params; j++) {
4963			if (strcmp(data->params[j], data_test->params[j]) != 0)
4964				return false;
4965		}
4966
4967		if (data->use_trace_keyword)
4968			action_name = data->synth_event_name;
4969		else
4970			action_name = data->action_name;
4971
4972		if (data_test->use_trace_keyword)
4973			action_name_test = data_test->synth_event_name;
4974		else
4975			action_name_test = data_test->action_name;
4976
4977		if (strcmp(action_name, action_name_test) != 0)
4978			return false;
4979
4980		if (data->handler == HANDLER_ONMATCH) {
4981			if (strcmp(data->match_data.event_system,
4982				   data_test->match_data.event_system) != 0)
4983				return false;
4984			if (strcmp(data->match_data.event,
4985				   data_test->match_data.event) != 0)
4986				return false;
4987		} else if (data->handler == HANDLER_ONMAX ||
4988			   data->handler == HANDLER_ONCHANGE) {
4989			if (strcmp(data->track_data.var_str,
4990				   data_test->track_data.var_str) != 0)
4991				return false;
4992		}
4993	}
4994
4995	return true;
4996}
4997
4998
4999static void print_actions_spec(struct seq_file *m,
5000			       struct hist_trigger_data *hist_data)
5001{
5002	unsigned int i;
5003
5004	for (i = 0; i < hist_data->n_actions; i++) {
5005		struct action_data *data = hist_data->actions[i];
5006
5007		if (data->handler == HANDLER_ONMATCH)
5008			print_onmatch_spec(m, hist_data, data);
5009		else if (data->handler == HANDLER_ONMAX ||
5010			 data->handler == HANDLER_ONCHANGE)
5011			print_track_data_spec(m, hist_data, data);
5012	}
5013}
5014
5015static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
5016{
5017	unsigned int i;
5018
5019	for (i = 0; i < hist_data->n_field_var_hists; i++) {
5020		kfree(hist_data->field_var_hists[i]->cmd);
5021		kfree(hist_data->field_var_hists[i]);
5022	}
5023}
5024
5025static void destroy_hist_data(struct hist_trigger_data *hist_data)
5026{
5027	if (!hist_data)
5028		return;
5029
5030	destroy_hist_trigger_attrs(hist_data->attrs);
5031	destroy_hist_fields(hist_data);
5032	tracing_map_destroy(hist_data->map);
5033
5034	destroy_actions(hist_data);
5035	destroy_field_vars(hist_data);
5036	destroy_field_var_hists(hist_data);
5037
5038	kfree(hist_data);
5039}
5040
5041static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
5042{
5043	struct tracing_map *map = hist_data->map;
5044	struct ftrace_event_field *field;
5045	struct hist_field *hist_field;
5046	int i, idx = 0;
5047
5048	for_each_hist_field(i, hist_data) {
5049		hist_field = hist_data->fields[i];
5050		if (hist_field->flags & HIST_FIELD_FL_KEY) {
5051			tracing_map_cmp_fn_t cmp_fn;
5052
5053			field = hist_field->field;
5054
5055			if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
5056				cmp_fn = tracing_map_cmp_none;
5057			else if (!field || hist_field->flags & HIST_FIELD_FL_CPU)
5058				cmp_fn = tracing_map_cmp_num(hist_field->size,
5059							     hist_field->is_signed);
5060			else if (is_string_field(field))
5061				cmp_fn = tracing_map_cmp_string;
5062			else
5063				cmp_fn = tracing_map_cmp_num(field->size,
5064							     field->is_signed);
5065			idx = tracing_map_add_key_field(map,
5066							hist_field->offset,
5067							cmp_fn);
5068		} else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
5069			idx = tracing_map_add_sum_field(map);
5070
5071		if (idx < 0)
5072			return idx;
5073
5074		if (hist_field->flags & HIST_FIELD_FL_VAR) {
5075			idx = tracing_map_add_var(map);
5076			if (idx < 0)
5077				return idx;
5078			hist_field->var.idx = idx;
5079			hist_field->var.hist_data = hist_data;
5080		}
5081	}
5082
5083	return 0;
5084}
5085
5086static struct hist_trigger_data *
5087create_hist_data(unsigned int map_bits,
5088		 struct hist_trigger_attrs *attrs,
5089		 struct trace_event_file *file,
5090		 bool remove)
5091{
5092	const struct tracing_map_ops *map_ops = NULL;
5093	struct hist_trigger_data *hist_data;
5094	int ret = 0;
5095
5096	hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
5097	if (!hist_data)
5098		return ERR_PTR(-ENOMEM);
5099
5100	hist_data->attrs = attrs;
5101	hist_data->remove = remove;
5102	hist_data->event_file = file;
5103
5104	ret = parse_actions(hist_data);
5105	if (ret)
5106		goto free;
5107
5108	ret = create_hist_fields(hist_data, file);
5109	if (ret)
5110		goto free;
5111
5112	ret = create_sort_keys(hist_data);
5113	if (ret)
5114		goto free;
5115
5116	map_ops = &hist_trigger_elt_data_ops;
5117
5118	hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
5119					    map_ops, hist_data);
5120	if (IS_ERR(hist_data->map)) {
5121		ret = PTR_ERR(hist_data->map);
5122		hist_data->map = NULL;
5123		goto free;
5124	}
5125
5126	ret = create_tracing_map_fields(hist_data);
5127	if (ret)
5128		goto free;
5129 out:
5130	return hist_data;
5131 free:
5132	hist_data->attrs = NULL;
5133
5134	destroy_hist_data(hist_data);
5135
5136	hist_data = ERR_PTR(ret);
5137
5138	goto out;
5139}
5140
5141static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
5142				    struct tracing_map_elt *elt,
5143				    struct trace_buffer *buffer, void *rec,
5144				    struct ring_buffer_event *rbe,
5145				    u64 *var_ref_vals)
5146{
5147	struct hist_elt_data *elt_data;
5148	struct hist_field *hist_field;
5149	unsigned int i, var_idx;
5150	u64 hist_val;
5151
5152	elt_data = elt->private_data;
5153	elt_data->var_ref_vals = var_ref_vals;
5154
5155	for_each_hist_val_field(i, hist_data) {
5156		hist_field = hist_data->fields[i];
5157		hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
5158		if (hist_field->flags & HIST_FIELD_FL_VAR) {
5159			var_idx = hist_field->var.idx;
5160
5161			if (hist_field->flags &
5162			    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE)) {
5163				unsigned int str_start, var_str_idx, idx;
5164				char *str, *val_str;
5165				unsigned int size;
5166
5167				str_start = hist_data->n_field_var_str +
5168					hist_data->n_save_var_str;
5169				var_str_idx = hist_field->var_str_idx;
5170				idx = str_start + var_str_idx;
5171
5172				str = elt_data->field_var_str[idx];
5173				val_str = (char *)(uintptr_t)hist_val;
5174
5175				if (hist_field->flags & HIST_FIELD_FL_STRING) {
5176					size = min(hist_field->size, STR_VAR_LEN_MAX);
5177					strscpy(str, val_str, size);
5178				} else {
5179					char *stack_start = str + sizeof(unsigned long);
5180					int e;
5181
5182					e = stack_trace_save((void *)stack_start,
5183							     HIST_STACKTRACE_DEPTH,
5184							     HIST_STACKTRACE_SKIP);
5185					if (e < HIST_STACKTRACE_DEPTH - 1)
5186						((unsigned long *)stack_start)[e] = 0;
5187					*((unsigned long *)str) = e;
5188				}
5189				hist_val = (u64)(uintptr_t)str;
5190			}
5191			tracing_map_set_var(elt, var_idx, hist_val);
5192			continue;
5193		}
5194		tracing_map_update_sum(elt, i, hist_val);
5195	}
5196
5197	for_each_hist_key_field(i, hist_data) {
5198		hist_field = hist_data->fields[i];
5199		if (hist_field->flags & HIST_FIELD_FL_VAR) {
5200			hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
5201			var_idx = hist_field->var.idx;
5202			tracing_map_set_var(elt, var_idx, hist_val);
5203		}
5204	}
5205
5206	update_field_vars(hist_data, elt, buffer, rbe, rec);
5207}
5208
5209static inline void add_to_key(char *compound_key, void *key,
5210			      struct hist_field *key_field, void *rec)
5211{
5212	size_t size = key_field->size;
5213
5214	if (key_field->flags & HIST_FIELD_FL_STRING) {
5215		struct ftrace_event_field *field;
5216
5217		field = key_field->field;
5218		if (field->filter_type == FILTER_DYN_STRING ||
5219		    field->filter_type == FILTER_RDYN_STRING)
5220			size = *(u32 *)(rec + field->offset) >> 16;
5221		else if (field->filter_type == FILTER_STATIC_STRING)
5222			size = field->size;
5223
5224		/* ensure NULL-termination */
5225		if (size > key_field->size - 1)
5226			size = key_field->size - 1;
5227
5228		strncpy(compound_key + key_field->offset, (char *)key, size);
5229	} else
5230		memcpy(compound_key + key_field->offset, key, size);
5231}
5232
5233static void
5234hist_trigger_actions(struct hist_trigger_data *hist_data,
5235		     struct tracing_map_elt *elt,
5236		     struct trace_buffer *buffer, void *rec,
5237		     struct ring_buffer_event *rbe, void *key,
5238		     u64 *var_ref_vals)
5239{
5240	struct action_data *data;
5241	unsigned int i;
5242
5243	for (i = 0; i < hist_data->n_actions; i++) {
5244		data = hist_data->actions[i];
5245		data->fn(hist_data, elt, buffer, rec, rbe, key, data, var_ref_vals);
5246	}
5247}
5248
5249static void event_hist_trigger(struct event_trigger_data *data,
5250			       struct trace_buffer *buffer, void *rec,
5251			       struct ring_buffer_event *rbe)
5252{
5253	struct hist_trigger_data *hist_data = data->private_data;
5254	bool use_compound_key = (hist_data->n_keys > 1);
5255	unsigned long entries[HIST_STACKTRACE_DEPTH];
5256	u64 var_ref_vals[TRACING_MAP_VARS_MAX];
5257	char compound_key[HIST_KEY_SIZE_MAX];
5258	struct tracing_map_elt *elt = NULL;
5259	struct hist_field *key_field;
5260	u64 field_contents;
5261	void *key = NULL;
5262	unsigned int i;
5263
5264	if (unlikely(!rbe))
5265		return;
5266
5267	memset(compound_key, 0, hist_data->key_size);
5268
5269	for_each_hist_key_field(i, hist_data) {
5270		key_field = hist_data->fields[i];
5271
5272		if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5273			memset(entries, 0, HIST_STACKTRACE_SIZE);
5274			if (key_field->field) {
5275				unsigned long *stack, n_entries;
5276
5277				field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
5278				stack = (unsigned long *)(long)field_contents;
5279				n_entries = *stack;
5280				memcpy(entries, ++stack, n_entries * sizeof(unsigned long));
5281			} else {
5282				stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
5283						 HIST_STACKTRACE_SKIP);
5284			}
5285			key = entries;
5286		} else {
5287			field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
5288			if (key_field->flags & HIST_FIELD_FL_STRING) {
5289				key = (void *)(unsigned long)field_contents;
5290				use_compound_key = true;
5291			} else
5292				key = (void *)&field_contents;
5293		}
5294
5295		if (use_compound_key)
5296			add_to_key(compound_key, key, key_field, rec);
5297	}
5298
5299	if (use_compound_key)
5300		key = compound_key;
5301
5302	if (hist_data->n_var_refs &&
5303	    !resolve_var_refs(hist_data, key, var_ref_vals, false))
5304		return;
5305
5306	elt = tracing_map_insert(hist_data->map, key);
5307	if (!elt)
5308		return;
5309
5310	hist_trigger_elt_update(hist_data, elt, buffer, rec, rbe, var_ref_vals);
5311
5312	if (resolve_var_refs(hist_data, key, var_ref_vals, true))
5313		hist_trigger_actions(hist_data, elt, buffer, rec, rbe, key, var_ref_vals);
5314}
5315
5316static void hist_trigger_stacktrace_print(struct seq_file *m,
5317					  unsigned long *stacktrace_entries,
5318					  unsigned int max_entries)
5319{
5320	unsigned int spaces = 8;
5321	unsigned int i;
5322
5323	for (i = 0; i < max_entries; i++) {
5324		if (!stacktrace_entries[i])
5325			return;
5326
5327		seq_printf(m, "%*c", 1 + spaces, ' ');
5328		seq_printf(m, "%pS\n", (void*)stacktrace_entries[i]);
5329	}
5330}
5331
5332static void hist_trigger_print_key(struct seq_file *m,
5333				   struct hist_trigger_data *hist_data,
5334				   void *key,
5335				   struct tracing_map_elt *elt)
5336{
5337	struct hist_field *key_field;
5338	bool multiline = false;
5339	const char *field_name;
5340	unsigned int i;
5341	u64 uval;
5342
5343	seq_puts(m, "{ ");
5344
5345	for_each_hist_key_field(i, hist_data) {
5346		key_field = hist_data->fields[i];
5347
5348		if (i > hist_data->n_vals)
5349			seq_puts(m, ", ");
5350
5351		field_name = hist_field_name(key_field, 0);
5352
5353		if (key_field->flags & HIST_FIELD_FL_HEX) {
5354			uval = *(u64 *)(key + key_field->offset);
5355			seq_printf(m, "%s: %llx", field_name, uval);
5356		} else if (key_field->flags & HIST_FIELD_FL_SYM) {
5357			uval = *(u64 *)(key + key_field->offset);
5358			seq_printf(m, "%s: [%llx] %-45ps", field_name,
5359				   uval, (void *)(uintptr_t)uval);
5360		} else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
5361			uval = *(u64 *)(key + key_field->offset);
5362			seq_printf(m, "%s: [%llx] %-55pS", field_name,
5363				   uval, (void *)(uintptr_t)uval);
5364		} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
5365			struct hist_elt_data *elt_data = elt->private_data;
5366			char *comm;
5367
5368			if (WARN_ON_ONCE(!elt_data))
5369				return;
5370
5371			comm = elt_data->comm;
5372
5373			uval = *(u64 *)(key + key_field->offset);
5374			seq_printf(m, "%s: %-16s[%10llu]", field_name,
5375				   comm, uval);
5376		} else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
5377			const char *syscall_name;
5378
5379			uval = *(u64 *)(key + key_field->offset);
5380			syscall_name = get_syscall_name(uval);
5381			if (!syscall_name)
5382				syscall_name = "unknown_syscall";
5383
5384			seq_printf(m, "%s: %-30s[%3llu]", field_name,
5385				   syscall_name, uval);
5386		} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5387			if (key_field->field)
5388				seq_printf(m, "%s.stacktrace", key_field->field->name);
5389			else
5390				seq_puts(m, "common_stacktrace:\n");
5391			hist_trigger_stacktrace_print(m,
5392						      key + key_field->offset,
5393						      HIST_STACKTRACE_DEPTH);
5394			multiline = true;
5395		} else if (key_field->flags & HIST_FIELD_FL_LOG2) {
5396			seq_printf(m, "%s: ~ 2^%-2llu", field_name,
5397				   *(u64 *)(key + key_field->offset));
5398		} else if (key_field->flags & HIST_FIELD_FL_BUCKET) {
5399			unsigned long buckets = key_field->buckets;
5400			uval = *(u64 *)(key + key_field->offset);
5401			seq_printf(m, "%s: ~ %llu-%llu", field_name,
5402				   uval, uval + buckets -1);
5403		} else if (key_field->flags & HIST_FIELD_FL_STRING) {
5404			seq_printf(m, "%s: %-50s", field_name,
5405				   (char *)(key + key_field->offset));
5406		} else {
5407			uval = *(u64 *)(key + key_field->offset);
5408			seq_printf(m, "%s: %10llu", field_name, uval);
5409		}
5410	}
5411
5412	if (!multiline)
5413		seq_puts(m, " ");
5414
5415	seq_puts(m, "}");
5416}
5417
5418/* Get the 100 times of the percentage of @val in @total */
5419static inline unsigned int __get_percentage(u64 val, u64 total)
5420{
5421	if (!total)
5422		goto div0;
5423
5424	if (val < (U64_MAX / 10000))
5425		return (unsigned int)div64_ul(val * 10000, total);
5426
5427	total = div64_u64(total, 10000);
5428	if (!total)
5429		goto div0;
5430
5431	return (unsigned int)div64_ul(val, total);
5432div0:
5433	return val ? UINT_MAX : 0;
5434}
5435
5436#define BAR_CHAR '#'
5437
5438static inline const char *__fill_bar_str(char *buf, int size, u64 val, u64 max)
5439{
5440	unsigned int len = __get_percentage(val, max);
5441	int i;
5442
5443	if (len == UINT_MAX) {
5444		snprintf(buf, size, "[ERROR]");
5445		return buf;
5446	}
5447
5448	len = len * size / 10000;
5449	for (i = 0; i < len && i < size; i++)
5450		buf[i] = BAR_CHAR;
5451	while (i < size)
5452		buf[i++] = ' ';
5453	buf[size] = '\0';
5454
5455	return buf;
5456}
5457
5458struct hist_val_stat {
5459	u64 max;
5460	u64 total;
5461};
5462
5463static void hist_trigger_print_val(struct seq_file *m, unsigned int idx,
5464				   const char *field_name, unsigned long flags,
5465				   struct hist_val_stat *stats,
5466				   struct tracing_map_elt *elt)
5467{
5468	u64 val = tracing_map_read_sum(elt, idx);
5469	unsigned int pc;
5470	char bar[21];
5471
5472	if (flags & HIST_FIELD_FL_PERCENT) {
5473		pc = __get_percentage(val, stats[idx].total);
5474		if (pc == UINT_MAX)
5475			seq_printf(m, " %s (%%):[ERROR]", field_name);
5476		else
5477			seq_printf(m, " %s (%%): %3u.%02u", field_name,
5478					pc / 100, pc % 100);
5479	} else if (flags & HIST_FIELD_FL_GRAPH) {
5480		seq_printf(m, " %s: %20s", field_name,
5481			   __fill_bar_str(bar, 20, val, stats[idx].max));
5482	} else if (flags & HIST_FIELD_FL_HEX) {
5483		seq_printf(m, " %s: %10llx", field_name, val);
5484	} else {
5485		seq_printf(m, " %s: %10llu", field_name, val);
5486	}
5487}
5488
5489static void hist_trigger_entry_print(struct seq_file *m,
5490				     struct hist_trigger_data *hist_data,
5491				     struct hist_val_stat *stats,
5492				     void *key,
5493				     struct tracing_map_elt *elt)
5494{
5495	const char *field_name;
5496	unsigned int i = HITCOUNT_IDX;
5497	unsigned long flags;
5498
5499	hist_trigger_print_key(m, hist_data, key, elt);
5500
5501	/* At first, show the raw hitcount if !nohitcount */
5502	if (!hist_data->attrs->no_hitcount)
5503		hist_trigger_print_val(m, i, "hitcount", 0, stats, elt);
5504
5505	for (i = 1; i < hist_data->n_vals; i++) {
5506		field_name = hist_field_name(hist_data->fields[i], 0);
5507		flags = hist_data->fields[i]->flags;
5508		if (flags & HIST_FIELD_FL_VAR || flags & HIST_FIELD_FL_EXPR)
5509			continue;
5510
5511		seq_puts(m, " ");
5512		hist_trigger_print_val(m, i, field_name, flags, stats, elt);
5513	}
5514
5515	print_actions(m, hist_data, elt);
5516
5517	seq_puts(m, "\n");
5518}
5519
5520static int print_entries(struct seq_file *m,
5521			 struct hist_trigger_data *hist_data)
5522{
5523	struct tracing_map_sort_entry **sort_entries = NULL;
5524	struct tracing_map *map = hist_data->map;
5525	int i, j, n_entries;
5526	struct hist_val_stat *stats = NULL;
5527	u64 val;
5528
5529	n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
5530					     hist_data->n_sort_keys,
5531					     &sort_entries);
5532	if (n_entries < 0)
5533		return n_entries;
5534
5535	/* Calculate the max and the total for each field if needed. */
5536	for (j = 0; j < hist_data->n_vals; j++) {
5537		if (!(hist_data->fields[j]->flags &
5538			(HIST_FIELD_FL_PERCENT | HIST_FIELD_FL_GRAPH)))
5539			continue;
5540		if (!stats) {
5541			stats = kcalloc(hist_data->n_vals, sizeof(*stats),
5542				       GFP_KERNEL);
5543			if (!stats) {
5544				n_entries = -ENOMEM;
5545				goto out;
5546			}
5547		}
5548		for (i = 0; i < n_entries; i++) {
5549			val = tracing_map_read_sum(sort_entries[i]->elt, j);
5550			stats[j].total += val;
5551			if (stats[j].max < val)
5552				stats[j].max = val;
5553		}
5554	}
5555
5556	for (i = 0; i < n_entries; i++)
5557		hist_trigger_entry_print(m, hist_data, stats,
5558					 sort_entries[i]->key,
5559					 sort_entries[i]->elt);
5560
5561	kfree(stats);
5562out:
5563	tracing_map_destroy_sort_entries(sort_entries, n_entries);
5564
5565	return n_entries;
5566}
5567
5568static void hist_trigger_show(struct seq_file *m,
5569			      struct event_trigger_data *data, int n)
5570{
5571	struct hist_trigger_data *hist_data;
5572	int n_entries;
5573
5574	if (n > 0)
5575		seq_puts(m, "\n\n");
5576
5577	seq_puts(m, "# event histogram\n#\n# trigger info: ");
5578	data->ops->print(m, data);
5579	seq_puts(m, "#\n\n");
5580
5581	hist_data = data->private_data;
5582	n_entries = print_entries(m, hist_data);
5583	if (n_entries < 0)
5584		n_entries = 0;
5585
5586	track_data_snapshot_print(m, hist_data);
5587
5588	seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
5589		   (u64)atomic64_read(&hist_data->map->hits),
5590		   n_entries, (u64)atomic64_read(&hist_data->map->drops));
5591}
5592
5593static int hist_show(struct seq_file *m, void *v)
5594{
5595	struct event_trigger_data *data;
5596	struct trace_event_file *event_file;
5597	int n = 0, ret = 0;
5598
5599	mutex_lock(&event_mutex);
5600
5601	event_file = event_file_file(m->private);
5602	if (unlikely(!event_file)) {
5603		ret = -ENODEV;
5604		goto out_unlock;
5605	}
5606
5607	list_for_each_entry(data, &event_file->triggers, list) {
5608		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5609			hist_trigger_show(m, data, n++);
5610	}
5611
5612 out_unlock:
5613	mutex_unlock(&event_mutex);
5614
5615	return ret;
5616}
5617
5618static int event_hist_open(struct inode *inode, struct file *file)
5619{
5620	int ret;
5621
5622	ret = tracing_open_file_tr(inode, file);
5623	if (ret)
5624		return ret;
5625
5626	/* Clear private_data to avoid warning in single_open() */
5627	file->private_data = NULL;
5628	return single_open(file, hist_show, file);
5629}
5630
5631const struct file_operations event_hist_fops = {
5632	.open = event_hist_open,
5633	.read = seq_read,
5634	.llseek = seq_lseek,
5635	.release = tracing_single_release_file_tr,
5636};
5637
5638#ifdef CONFIG_HIST_TRIGGERS_DEBUG
5639static void hist_field_debug_show_flags(struct seq_file *m,
5640					unsigned long flags)
5641{
5642	seq_puts(m, "      flags:\n");
5643
5644	if (flags & HIST_FIELD_FL_KEY)
5645		seq_puts(m, "        HIST_FIELD_FL_KEY\n");
5646	else if (flags & HIST_FIELD_FL_HITCOUNT)
5647		seq_puts(m, "        VAL: HIST_FIELD_FL_HITCOUNT\n");
5648	else if (flags & HIST_FIELD_FL_VAR)
5649		seq_puts(m, "        HIST_FIELD_FL_VAR\n");
5650	else if (flags & HIST_FIELD_FL_VAR_REF)
5651		seq_puts(m, "        HIST_FIELD_FL_VAR_REF\n");
5652	else
5653		seq_puts(m, "        VAL: normal u64 value\n");
5654
5655	if (flags & HIST_FIELD_FL_ALIAS)
5656		seq_puts(m, "        HIST_FIELD_FL_ALIAS\n");
5657	else if (flags & HIST_FIELD_FL_CONST)
5658		seq_puts(m, "        HIST_FIELD_FL_CONST\n");
5659}
5660
5661static int hist_field_debug_show(struct seq_file *m,
5662				 struct hist_field *field, unsigned long flags)
5663{
5664	if ((field->flags & flags) != flags) {
5665		seq_printf(m, "ERROR: bad flags - %lx\n", flags);
5666		return -EINVAL;
5667	}
5668
5669	hist_field_debug_show_flags(m, field->flags);
5670	if (field->field)
5671		seq_printf(m, "      ftrace_event_field name: %s\n",
5672			   field->field->name);
5673
5674	if (field->flags & HIST_FIELD_FL_VAR) {
5675		seq_printf(m, "      var.name: %s\n", field->var.name);
5676		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5677			   field->var.idx);
5678	}
5679
5680	if (field->flags & HIST_FIELD_FL_CONST)
5681		seq_printf(m, "      constant: %llu\n", field->constant);
5682
5683	if (field->flags & HIST_FIELD_FL_ALIAS)
5684		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5685			   field->var_ref_idx);
5686
5687	if (field->flags & HIST_FIELD_FL_VAR_REF) {
5688		seq_printf(m, "      name: %s\n", field->name);
5689		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5690			   field->var.idx);
5691		seq_printf(m, "      var.hist_data: %p\n", field->var.hist_data);
5692		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5693			   field->var_ref_idx);
5694		if (field->system)
5695			seq_printf(m, "      system: %s\n", field->system);
5696		if (field->event_name)
5697			seq_printf(m, "      event_name: %s\n", field->event_name);
5698	}
5699
5700	seq_printf(m, "      type: %s\n", field->type);
5701	seq_printf(m, "      size: %u\n", field->size);
5702	seq_printf(m, "      is_signed: %u\n", field->is_signed);
5703
5704	return 0;
5705}
5706
5707static int field_var_debug_show(struct seq_file *m,
5708				struct field_var *field_var, unsigned int i,
5709				bool save_vars)
5710{
5711	const char *vars_name = save_vars ? "save_vars" : "field_vars";
5712	struct hist_field *field;
5713	int ret = 0;
5714
5715	seq_printf(m, "\n    hist_data->%s[%d]:\n", vars_name, i);
5716
5717	field = field_var->var;
5718
5719	seq_printf(m, "\n      %s[%d].var:\n", vars_name, i);
5720
5721	hist_field_debug_show_flags(m, field->flags);
5722	seq_printf(m, "      var.name: %s\n", field->var.name);
5723	seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5724		   field->var.idx);
5725
5726	field = field_var->val;
5727
5728	seq_printf(m, "\n      %s[%d].val:\n", vars_name, i);
5729	if (field->field)
5730		seq_printf(m, "      ftrace_event_field name: %s\n",
5731			   field->field->name);
5732	else {
5733		ret = -EINVAL;
5734		goto out;
5735	}
5736
5737	seq_printf(m, "      type: %s\n", field->type);
5738	seq_printf(m, "      size: %u\n", field->size);
5739	seq_printf(m, "      is_signed: %u\n", field->is_signed);
5740out:
5741	return ret;
5742}
5743
5744static int hist_action_debug_show(struct seq_file *m,
5745				  struct action_data *data, int i)
5746{
5747	int ret = 0;
5748
5749	if (data->handler == HANDLER_ONMAX ||
5750	    data->handler == HANDLER_ONCHANGE) {
5751		seq_printf(m, "\n    hist_data->actions[%d].track_data.var_ref:\n", i);
5752		ret = hist_field_debug_show(m, data->track_data.var_ref,
5753					    HIST_FIELD_FL_VAR_REF);
5754		if (ret)
5755			goto out;
5756
5757		seq_printf(m, "\n    hist_data->actions[%d].track_data.track_var:\n", i);
5758		ret = hist_field_debug_show(m, data->track_data.track_var,
5759					    HIST_FIELD_FL_VAR);
5760		if (ret)
5761			goto out;
5762	}
5763
5764	if (data->handler == HANDLER_ONMATCH) {
5765		seq_printf(m, "\n    hist_data->actions[%d].match_data.event_system: %s\n",
5766			   i, data->match_data.event_system);
5767		seq_printf(m, "    hist_data->actions[%d].match_data.event: %s\n",
5768			   i, data->match_data.event);
5769	}
5770out:
5771	return ret;
5772}
5773
5774static int hist_actions_debug_show(struct seq_file *m,
5775				   struct hist_trigger_data *hist_data)
5776{
5777	int i, ret = 0;
5778
5779	if (hist_data->n_actions)
5780		seq_puts(m, "\n  action tracking variables (for onmax()/onchange()/onmatch()):\n");
5781
5782	for (i = 0; i < hist_data->n_actions; i++) {
5783		struct action_data *action = hist_data->actions[i];
5784
5785		ret = hist_action_debug_show(m, action, i);
5786		if (ret)
5787			goto out;
5788	}
5789
5790	if (hist_data->n_save_vars)
5791		seq_puts(m, "\n  save action variables (save() params):\n");
5792
5793	for (i = 0; i < hist_data->n_save_vars; i++) {
5794		ret = field_var_debug_show(m, hist_data->save_vars[i], i, true);
5795		if (ret)
5796			goto out;
5797	}
5798out:
5799	return ret;
5800}
5801
5802static void hist_trigger_debug_show(struct seq_file *m,
5803				    struct event_trigger_data *data, int n)
5804{
5805	struct hist_trigger_data *hist_data;
5806	int i, ret;
5807
5808	if (n > 0)
5809		seq_puts(m, "\n\n");
5810
5811	seq_puts(m, "# event histogram\n#\n# trigger info: ");
5812	data->ops->print(m, data);
5813	seq_puts(m, "#\n\n");
5814
5815	hist_data = data->private_data;
5816
5817	seq_printf(m, "hist_data: %p\n\n", hist_data);
5818	seq_printf(m, "  n_vals: %u\n", hist_data->n_vals);
5819	seq_printf(m, "  n_keys: %u\n", hist_data->n_keys);
5820	seq_printf(m, "  n_fields: %u\n", hist_data->n_fields);
5821
5822	seq_puts(m, "\n  val fields:\n\n");
5823
5824	seq_puts(m, "    hist_data->fields[0]:\n");
5825	ret = hist_field_debug_show(m, hist_data->fields[0],
5826				    HIST_FIELD_FL_HITCOUNT);
5827	if (ret)
5828		return;
5829
5830	for (i = 1; i < hist_data->n_vals; i++) {
5831		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
5832		ret = hist_field_debug_show(m, hist_data->fields[i], 0);
5833		if (ret)
5834			return;
5835	}
5836
5837	seq_puts(m, "\n  key fields:\n");
5838
5839	for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
5840		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
5841		ret = hist_field_debug_show(m, hist_data->fields[i],
5842					    HIST_FIELD_FL_KEY);
5843		if (ret)
5844			return;
5845	}
5846
5847	if (hist_data->n_var_refs)
5848		seq_puts(m, "\n  variable reference fields:\n");
5849
5850	for (i = 0; i < hist_data->n_var_refs; i++) {
5851		seq_printf(m, "\n    hist_data->var_refs[%d]:\n", i);
5852		ret = hist_field_debug_show(m, hist_data->var_refs[i],
5853					    HIST_FIELD_FL_VAR_REF);
5854		if (ret)
5855			return;
5856	}
5857
5858	if (hist_data->n_field_vars)
5859		seq_puts(m, "\n  field variables:\n");
5860
5861	for (i = 0; i < hist_data->n_field_vars; i++) {
5862		ret = field_var_debug_show(m, hist_data->field_vars[i], i, false);
5863		if (ret)
5864			return;
5865	}
5866
5867	ret = hist_actions_debug_show(m, hist_data);
5868	if (ret)
5869		return;
5870}
5871
5872static int hist_debug_show(struct seq_file *m, void *v)
5873{
5874	struct event_trigger_data *data;
5875	struct trace_event_file *event_file;
5876	int n = 0, ret = 0;
5877
5878	mutex_lock(&event_mutex);
5879
5880	event_file = event_file_file(m->private);
5881	if (unlikely(!event_file)) {
5882		ret = -ENODEV;
5883		goto out_unlock;
5884	}
5885
5886	list_for_each_entry(data, &event_file->triggers, list) {
5887		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5888			hist_trigger_debug_show(m, data, n++);
5889	}
5890
5891 out_unlock:
5892	mutex_unlock(&event_mutex);
5893
5894	return ret;
5895}
5896
5897static int event_hist_debug_open(struct inode *inode, struct file *file)
5898{
5899	int ret;
5900
5901	ret = tracing_open_file_tr(inode, file);
5902	if (ret)
5903		return ret;
5904
5905	/* Clear private_data to avoid warning in single_open() */
5906	file->private_data = NULL;
5907	return single_open(file, hist_debug_show, file);
5908}
5909
5910const struct file_operations event_hist_debug_fops = {
5911	.open = event_hist_debug_open,
5912	.read = seq_read,
5913	.llseek = seq_lseek,
5914	.release = tracing_single_release_file_tr,
5915};
5916#endif
5917
5918static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
5919{
5920	const char *field_name = hist_field_name(hist_field, 0);
5921
5922	if (hist_field->var.name)
5923		seq_printf(m, "%s=", hist_field->var.name);
5924
5925	if (hist_field->flags & HIST_FIELD_FL_CPU)
5926		seq_puts(m, "common_cpu");
5927	else if (hist_field->flags & HIST_FIELD_FL_CONST)
5928		seq_printf(m, "%llu", hist_field->constant);
5929	else if (field_name) {
5930		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
5931		    hist_field->flags & HIST_FIELD_FL_ALIAS)
5932			seq_putc(m, '$');
5933		seq_printf(m, "%s", field_name);
5934	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
5935		seq_puts(m, "common_timestamp");
5936
5937	if (hist_field->flags) {
5938		if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
5939		    !(hist_field->flags & HIST_FIELD_FL_EXPR) &&
5940		    !(hist_field->flags & HIST_FIELD_FL_STACKTRACE)) {
5941			const char *flags = get_hist_field_flags(hist_field);
5942
5943			if (flags)
5944				seq_printf(m, ".%s", flags);
5945		}
5946	}
5947	if (hist_field->buckets)
5948		seq_printf(m, "=%ld", hist_field->buckets);
5949}
5950
5951static int event_hist_trigger_print(struct seq_file *m,
5952				    struct event_trigger_data *data)
5953{
5954	struct hist_trigger_data *hist_data = data->private_data;
5955	struct hist_field *field;
5956	bool have_var = false;
5957	bool show_val = false;
5958	unsigned int i;
5959
5960	seq_puts(m, HIST_PREFIX);
5961
5962	if (data->name)
5963		seq_printf(m, "%s:", data->name);
5964
5965	seq_puts(m, "keys=");
5966
5967	for_each_hist_key_field(i, hist_data) {
5968		field = hist_data->fields[i];
5969
5970		if (i > hist_data->n_vals)
5971			seq_puts(m, ",");
5972
5973		if (field->flags & HIST_FIELD_FL_STACKTRACE) {
5974			if (field->field)
5975				seq_printf(m, "%s.stacktrace", field->field->name);
5976			else
5977				seq_puts(m, "common_stacktrace");
5978		} else
5979			hist_field_print(m, field);
5980	}
5981
5982	seq_puts(m, ":vals=");
5983
5984	for_each_hist_val_field(i, hist_data) {
5985		field = hist_data->fields[i];
5986		if (field->flags & HIST_FIELD_FL_VAR) {
5987			have_var = true;
5988			continue;
5989		}
5990
5991		if (i == HITCOUNT_IDX) {
5992			if (hist_data->attrs->no_hitcount)
5993				continue;
5994			seq_puts(m, "hitcount");
5995		} else {
5996			if (show_val)
5997				seq_puts(m, ",");
5998			hist_field_print(m, field);
5999		}
6000		show_val = true;
6001	}
6002
6003	if (have_var) {
6004		unsigned int n = 0;
6005
6006		seq_puts(m, ":");
6007
6008		for_each_hist_val_field(i, hist_data) {
6009			field = hist_data->fields[i];
6010
6011			if (field->flags & HIST_FIELD_FL_VAR) {
6012				if (n++)
6013					seq_puts(m, ",");
6014				hist_field_print(m, field);
6015			}
6016		}
6017	}
6018
6019	seq_puts(m, ":sort=");
6020
6021	for (i = 0; i < hist_data->n_sort_keys; i++) {
6022		struct tracing_map_sort_key *sort_key;
6023		unsigned int idx, first_key_idx;
6024
6025		/* skip VAR vals */
6026		first_key_idx = hist_data->n_vals - hist_data->n_vars;
6027
6028		sort_key = &hist_data->sort_keys[i];
6029		idx = sort_key->field_idx;
6030
6031		if (WARN_ON(idx >= HIST_FIELDS_MAX))
6032			return -EINVAL;
6033
6034		if (i > 0)
6035			seq_puts(m, ",");
6036
6037		if (idx == HITCOUNT_IDX)
6038			seq_puts(m, "hitcount");
6039		else {
6040			if (idx >= first_key_idx)
6041				idx += hist_data->n_vars;
6042			hist_field_print(m, hist_data->fields[idx]);
6043		}
6044
6045		if (sort_key->descending)
6046			seq_puts(m, ".descending");
6047	}
6048	seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
6049	if (hist_data->enable_timestamps)
6050		seq_printf(m, ":clock=%s", hist_data->attrs->clock);
6051	if (hist_data->attrs->no_hitcount)
6052		seq_puts(m, ":nohitcount");
6053
6054	print_actions_spec(m, hist_data);
6055
6056	if (data->filter_str)
6057		seq_printf(m, " if %s", data->filter_str);
6058
6059	if (data->paused)
6060		seq_puts(m, " [paused]");
6061	else
6062		seq_puts(m, " [active]");
6063
6064	seq_putc(m, '\n');
6065
6066	return 0;
6067}
6068
6069static int event_hist_trigger_init(struct event_trigger_data *data)
6070{
6071	struct hist_trigger_data *hist_data = data->private_data;
6072
6073	if (!data->ref && hist_data->attrs->name)
6074		save_named_trigger(hist_data->attrs->name, data);
6075
6076	data->ref++;
6077
6078	return 0;
6079}
6080
6081static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
6082{
6083	struct trace_event_file *file;
6084	unsigned int i;
6085	char *cmd;
6086	int ret;
6087
6088	for (i = 0; i < hist_data->n_field_var_hists; i++) {
6089		file = hist_data->field_var_hists[i]->hist_data->event_file;
6090		cmd = hist_data->field_var_hists[i]->cmd;
6091		ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
6092					       "!hist", "hist", cmd);
6093		WARN_ON_ONCE(ret < 0);
6094	}
6095}
6096
6097static void event_hist_trigger_free(struct event_trigger_data *data)
6098{
6099	struct hist_trigger_data *hist_data = data->private_data;
6100
6101	if (WARN_ON_ONCE(data->ref <= 0))
6102		return;
6103
6104	data->ref--;
6105	if (!data->ref) {
6106		if (data->name)
6107			del_named_trigger(data);
6108
6109		trigger_data_free(data);
6110
6111		remove_hist_vars(hist_data);
6112
6113		unregister_field_var_hists(hist_data);
6114
6115		destroy_hist_data(hist_data);
6116	}
6117}
6118
6119static struct event_trigger_ops event_hist_trigger_ops = {
6120	.trigger		= event_hist_trigger,
6121	.print			= event_hist_trigger_print,
6122	.init			= event_hist_trigger_init,
6123	.free			= event_hist_trigger_free,
6124};
6125
6126static int event_hist_trigger_named_init(struct event_trigger_data *data)
6127{
6128	data->ref++;
6129
6130	save_named_trigger(data->named_data->name, data);
6131
6132	event_hist_trigger_init(data->named_data);
6133
6134	return 0;
6135}
6136
6137static void event_hist_trigger_named_free(struct event_trigger_data *data)
6138{
6139	if (WARN_ON_ONCE(data->ref <= 0))
6140		return;
6141
6142	event_hist_trigger_free(data->named_data);
6143
6144	data->ref--;
6145	if (!data->ref) {
6146		del_named_trigger(data);
6147		trigger_data_free(data);
6148	}
6149}
6150
6151static struct event_trigger_ops event_hist_trigger_named_ops = {
6152	.trigger		= event_hist_trigger,
6153	.print			= event_hist_trigger_print,
6154	.init			= event_hist_trigger_named_init,
6155	.free			= event_hist_trigger_named_free,
6156};
6157
6158static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
6159							    char *param)
6160{
6161	return &event_hist_trigger_ops;
6162}
6163
6164static void hist_clear(struct event_trigger_data *data)
6165{
6166	struct hist_trigger_data *hist_data = data->private_data;
6167
6168	if (data->name)
6169		pause_named_trigger(data);
6170
6171	tracepoint_synchronize_unregister();
6172
6173	tracing_map_clear(hist_data->map);
6174
6175	if (data->name)
6176		unpause_named_trigger(data);
6177}
6178
6179static bool compatible_field(struct ftrace_event_field *field,
6180			     struct ftrace_event_field *test_field)
6181{
6182	if (field == test_field)
6183		return true;
6184	if (field == NULL || test_field == NULL)
6185		return false;
6186	if (strcmp(field->name, test_field->name) != 0)
6187		return false;
6188	if (strcmp(field->type, test_field->type) != 0)
6189		return false;
6190	if (field->size != test_field->size)
6191		return false;
6192	if (field->is_signed != test_field->is_signed)
6193		return false;
6194
6195	return true;
6196}
6197
6198static bool hist_trigger_match(struct event_trigger_data *data,
6199			       struct event_trigger_data *data_test,
6200			       struct event_trigger_data *named_data,
6201			       bool ignore_filter)
6202{
6203	struct tracing_map_sort_key *sort_key, *sort_key_test;
6204	struct hist_trigger_data *hist_data, *hist_data_test;
6205	struct hist_field *key_field, *key_field_test;
6206	unsigned int i;
6207
6208	if (named_data && (named_data != data_test) &&
6209	    (named_data != data_test->named_data))
6210		return false;
6211
6212	if (!named_data && is_named_trigger(data_test))
6213		return false;
6214
6215	hist_data = data->private_data;
6216	hist_data_test = data_test->private_data;
6217
6218	if (hist_data->n_vals != hist_data_test->n_vals ||
6219	    hist_data->n_fields != hist_data_test->n_fields ||
6220	    hist_data->n_sort_keys != hist_data_test->n_sort_keys)
6221		return false;
6222
6223	if (!ignore_filter) {
6224		if ((data->filter_str && !data_test->filter_str) ||
6225		   (!data->filter_str && data_test->filter_str))
6226			return false;
6227	}
6228
6229	for_each_hist_field(i, hist_data) {
6230		key_field = hist_data->fields[i];
6231		key_field_test = hist_data_test->fields[i];
6232
6233		if (key_field->flags != key_field_test->flags)
6234			return false;
6235		if (!compatible_field(key_field->field, key_field_test->field))
6236			return false;
6237		if (key_field->offset != key_field_test->offset)
6238			return false;
6239		if (key_field->size != key_field_test->size)
6240			return false;
6241		if (key_field->is_signed != key_field_test->is_signed)
6242			return false;
6243		if (!!key_field->var.name != !!key_field_test->var.name)
6244			return false;
6245		if (key_field->var.name &&
6246		    strcmp(key_field->var.name, key_field_test->var.name) != 0)
6247			return false;
6248	}
6249
6250	for (i = 0; i < hist_data->n_sort_keys; i++) {
6251		sort_key = &hist_data->sort_keys[i];
6252		sort_key_test = &hist_data_test->sort_keys[i];
6253
6254		if (sort_key->field_idx != sort_key_test->field_idx ||
6255		    sort_key->descending != sort_key_test->descending)
6256			return false;
6257	}
6258
6259	if (!ignore_filter && data->filter_str &&
6260	    (strcmp(data->filter_str, data_test->filter_str) != 0))
6261		return false;
6262
6263	if (!actions_match(hist_data, hist_data_test))
6264		return false;
6265
6266	return true;
6267}
6268
6269static bool existing_hist_update_only(char *glob,
6270				      struct event_trigger_data *data,
6271				      struct trace_event_file *file)
6272{
6273	struct hist_trigger_data *hist_data = data->private_data;
6274	struct event_trigger_data *test, *named_data = NULL;
6275	bool updated = false;
6276
6277	if (!hist_data->attrs->pause && !hist_data->attrs->cont &&
6278	    !hist_data->attrs->clear)
6279		goto out;
6280
6281	if (hist_data->attrs->name) {
6282		named_data = find_named_trigger(hist_data->attrs->name);
6283		if (named_data) {
6284			if (!hist_trigger_match(data, named_data, named_data,
6285						true))
6286				goto out;
6287		}
6288	}
6289
6290	if (hist_data->attrs->name && !named_data)
6291		goto out;
6292
6293	list_for_each_entry(test, &file->triggers, list) {
6294		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6295			if (!hist_trigger_match(data, test, named_data, false))
6296				continue;
6297			if (hist_data->attrs->pause)
6298				test->paused = true;
6299			else if (hist_data->attrs->cont)
6300				test->paused = false;
6301			else if (hist_data->attrs->clear)
6302				hist_clear(test);
6303			updated = true;
6304			goto out;
6305		}
6306	}
6307 out:
6308	return updated;
6309}
6310
6311static int hist_register_trigger(char *glob,
6312				 struct event_trigger_data *data,
6313				 struct trace_event_file *file)
6314{
6315	struct hist_trigger_data *hist_data = data->private_data;
6316	struct event_trigger_data *test, *named_data = NULL;
6317	struct trace_array *tr = file->tr;
6318	int ret = 0;
6319
6320	if (hist_data->attrs->name) {
6321		named_data = find_named_trigger(hist_data->attrs->name);
6322		if (named_data) {
6323			if (!hist_trigger_match(data, named_data, named_data,
6324						true)) {
6325				hist_err(tr, HIST_ERR_NAMED_MISMATCH, errpos(hist_data->attrs->name));
6326				ret = -EINVAL;
6327				goto out;
6328			}
6329		}
6330	}
6331
6332	if (hist_data->attrs->name && !named_data)
6333		goto new;
6334
6335	lockdep_assert_held(&event_mutex);
6336
6337	list_for_each_entry(test, &file->triggers, list) {
6338		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6339			if (hist_trigger_match(data, test, named_data, false)) {
6340				hist_err(tr, HIST_ERR_TRIGGER_EEXIST, 0);
6341				ret = -EEXIST;
6342				goto out;
6343			}
6344		}
6345	}
6346 new:
6347	if (hist_data->attrs->cont || hist_data->attrs->clear) {
6348		hist_err(tr, HIST_ERR_TRIGGER_ENOENT_CLEAR, 0);
6349		ret = -ENOENT;
6350		goto out;
6351	}
6352
6353	if (hist_data->attrs->pause)
6354		data->paused = true;
6355
6356	if (named_data) {
6357		data->private_data = named_data->private_data;
6358		set_named_trigger_data(data, named_data);
6359		data->ops = &event_hist_trigger_named_ops;
6360	}
6361
6362	if (data->ops->init) {
6363		ret = data->ops->init(data);
6364		if (ret < 0)
6365			goto out;
6366	}
6367
6368	if (hist_data->enable_timestamps) {
6369		char *clock = hist_data->attrs->clock;
6370
6371		ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
6372		if (ret) {
6373			hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
6374			goto out;
6375		}
6376
6377		tracing_set_filter_buffering(file->tr, true);
6378	}
6379
6380	if (named_data)
6381		destroy_hist_data(hist_data);
6382 out:
6383	return ret;
6384}
6385
6386static int hist_trigger_enable(struct event_trigger_data *data,
6387			       struct trace_event_file *file)
6388{
6389	int ret = 0;
6390
6391	list_add_tail_rcu(&data->list, &file->triggers);
6392
6393	update_cond_flag(file);
6394
6395	if (trace_event_trigger_enable_disable(file, 1) < 0) {
6396		list_del_rcu(&data->list);
6397		update_cond_flag(file);
6398		ret--;
6399	}
6400
6401	return ret;
6402}
6403
6404static bool have_hist_trigger_match(struct event_trigger_data *data,
6405				    struct trace_event_file *file)
6406{
6407	struct hist_trigger_data *hist_data = data->private_data;
6408	struct event_trigger_data *test, *named_data = NULL;
6409	bool match = false;
6410
6411	lockdep_assert_held(&event_mutex);
6412
6413	if (hist_data->attrs->name)
6414		named_data = find_named_trigger(hist_data->attrs->name);
6415
6416	list_for_each_entry(test, &file->triggers, list) {
6417		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6418			if (hist_trigger_match(data, test, named_data, false)) {
6419				match = true;
6420				break;
6421			}
6422		}
6423	}
6424
6425	return match;
6426}
6427
6428static bool hist_trigger_check_refs(struct event_trigger_data *data,
6429				    struct trace_event_file *file)
6430{
6431	struct hist_trigger_data *hist_data = data->private_data;
6432	struct event_trigger_data *test, *named_data = NULL;
6433
6434	lockdep_assert_held(&event_mutex);
6435
6436	if (hist_data->attrs->name)
6437		named_data = find_named_trigger(hist_data->attrs->name);
6438
6439	list_for_each_entry(test, &file->triggers, list) {
6440		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6441			if (!hist_trigger_match(data, test, named_data, false))
6442				continue;
6443			hist_data = test->private_data;
6444			if (check_var_refs(hist_data))
6445				return true;
6446			break;
6447		}
6448	}
6449
6450	return false;
6451}
6452
6453static void hist_unregister_trigger(char *glob,
6454				    struct event_trigger_data *data,
6455				    struct trace_event_file *file)
6456{
6457	struct event_trigger_data *test = NULL, *iter, *named_data = NULL;
6458	struct hist_trigger_data *hist_data = data->private_data;
6459
6460	lockdep_assert_held(&event_mutex);
6461
6462	if (hist_data->attrs->name)
6463		named_data = find_named_trigger(hist_data->attrs->name);
6464
6465	list_for_each_entry(iter, &file->triggers, list) {
6466		if (iter->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6467			if (!hist_trigger_match(data, iter, named_data, false))
6468				continue;
6469			test = iter;
6470			list_del_rcu(&test->list);
6471			trace_event_trigger_enable_disable(file, 0);
6472			update_cond_flag(file);
6473			break;
6474		}
6475	}
6476
6477	if (test && test->ops->free)
6478		test->ops->free(test);
6479
6480	if (hist_data->enable_timestamps) {
6481		if (!hist_data->remove || test)
6482			tracing_set_filter_buffering(file->tr, false);
6483	}
6484}
6485
6486static bool hist_file_check_refs(struct trace_event_file *file)
6487{
6488	struct hist_trigger_data *hist_data;
6489	struct event_trigger_data *test;
6490
6491	lockdep_assert_held(&event_mutex);
6492
6493	list_for_each_entry(test, &file->triggers, list) {
6494		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6495			hist_data = test->private_data;
6496			if (check_var_refs(hist_data))
6497				return true;
6498		}
6499	}
6500
6501	return false;
6502}
6503
6504static void hist_unreg_all(struct trace_event_file *file)
6505{
6506	struct event_trigger_data *test, *n;
6507	struct hist_trigger_data *hist_data;
6508	struct synth_event *se;
6509	const char *se_name;
6510
6511	lockdep_assert_held(&event_mutex);
6512
6513	if (hist_file_check_refs(file))
6514		return;
6515
6516	list_for_each_entry_safe(test, n, &file->triggers, list) {
6517		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6518			hist_data = test->private_data;
6519			list_del_rcu(&test->list);
6520			trace_event_trigger_enable_disable(file, 0);
6521
6522			se_name = trace_event_name(file->event_call);
6523			se = find_synth_event(se_name);
6524			if (se)
6525				se->ref--;
6526
6527			update_cond_flag(file);
6528			if (hist_data->enable_timestamps)
6529				tracing_set_filter_buffering(file->tr, false);
6530			if (test->ops->free)
6531				test->ops->free(test);
6532		}
6533	}
6534}
6535
6536static int event_hist_trigger_parse(struct event_command *cmd_ops,
6537				    struct trace_event_file *file,
6538				    char *glob, char *cmd,
6539				    char *param_and_filter)
6540{
6541	unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
6542	struct event_trigger_data *trigger_data;
6543	struct hist_trigger_attrs *attrs;
6544	struct hist_trigger_data *hist_data;
6545	char *param, *filter, *p, *start;
6546	struct synth_event *se;
6547	const char *se_name;
6548	bool remove;
6549	int ret = 0;
6550
6551	lockdep_assert_held(&event_mutex);
6552
6553	if (WARN_ON(!glob))
6554		return -EINVAL;
6555
6556	if (glob[0]) {
6557		hist_err_clear();
6558		last_cmd_set(file, param_and_filter);
6559	}
6560
6561	remove = event_trigger_check_remove(glob);
6562
6563	if (event_trigger_empty_param(param_and_filter))
6564		return -EINVAL;
6565
6566	/*
6567	 * separate the trigger from the filter (k:v [if filter])
6568	 * allowing for whitespace in the trigger
6569	 */
6570	p = param = param_and_filter;
6571	do {
6572		p = strstr(p, "if");
6573		if (!p)
6574			break;
6575		if (p == param_and_filter)
6576			return -EINVAL;
6577		if (*(p - 1) != ' ' && *(p - 1) != '\t') {
6578			p++;
6579			continue;
6580		}
6581		if (p >= param_and_filter + strlen(param_and_filter) - (sizeof("if") - 1) - 1)
6582			return -EINVAL;
6583		if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
6584			p++;
6585			continue;
6586		}
6587		break;
6588	} while (1);
6589
6590	if (!p)
6591		filter = NULL;
6592	else {
6593		*(p - 1) = '\0';
6594		filter = strstrip(p);
6595		param = strstrip(param);
6596	}
6597
6598	/*
6599	 * To simplify arithmetic expression parsing, replace occurrences of
6600	 * '.sym-offset' modifier with '.symXoffset'
6601	 */
6602	start = strstr(param, ".sym-offset");
6603	while (start) {
6604		*(start + 4) = 'X';
6605		start = strstr(start + 11, ".sym-offset");
6606	}
6607
6608	attrs = parse_hist_trigger_attrs(file->tr, param);
6609	if (IS_ERR(attrs))
6610		return PTR_ERR(attrs);
6611
6612	if (attrs->map_bits)
6613		hist_trigger_bits = attrs->map_bits;
6614
6615	hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
6616	if (IS_ERR(hist_data)) {
6617		destroy_hist_trigger_attrs(attrs);
6618		return PTR_ERR(hist_data);
6619	}
6620
6621	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, hist_data);
6622	if (!trigger_data) {
6623		ret = -ENOMEM;
6624		goto out_free;
6625	}
6626
6627	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
6628	if (ret < 0)
6629		goto out_free;
6630
6631	if (remove) {
6632		if (!have_hist_trigger_match(trigger_data, file))
6633			goto out_free;
6634
6635		if (hist_trigger_check_refs(trigger_data, file)) {
6636			ret = -EBUSY;
6637			goto out_free;
6638		}
6639
6640		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
6641		se_name = trace_event_name(file->event_call);
6642		se = find_synth_event(se_name);
6643		if (se)
6644			se->ref--;
6645		ret = 0;
6646		goto out_free;
6647	}
6648
6649	if (existing_hist_update_only(glob, trigger_data, file))
6650		goto out_free;
6651
6652	if (!get_named_trigger_data(trigger_data)) {
6653
6654		ret = create_actions(hist_data);
6655		if (ret)
6656			goto out_free;
6657
6658		if (has_hist_vars(hist_data) || hist_data->n_var_refs) {
6659			ret = save_hist_vars(hist_data);
6660			if (ret)
6661				goto out_free;
6662		}
6663
6664		ret = tracing_map_init(hist_data->map);
6665		if (ret)
6666			goto out_free;
6667	}
6668
6669	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
6670	if (ret < 0)
6671		goto out_free;
6672
6673	ret = hist_trigger_enable(trigger_data, file);
6674	if (ret)
6675		goto out_unreg;
6676
6677	se_name = trace_event_name(file->event_call);
6678	se = find_synth_event(se_name);
6679	if (se)
6680		se->ref++;
6681 out:
6682	if (ret == 0 && glob[0])
6683		hist_err_clear();
6684
6685	return ret;
6686 out_unreg:
6687	event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
6688 out_free:
6689	event_trigger_reset_filter(cmd_ops, trigger_data);
6690
6691	remove_hist_vars(hist_data);
6692
6693	kfree(trigger_data);
6694
6695	destroy_hist_data(hist_data);
6696	goto out;
6697}
6698
6699static struct event_command trigger_hist_cmd = {
6700	.name			= "hist",
6701	.trigger_type		= ETT_EVENT_HIST,
6702	.flags			= EVENT_CMD_FL_NEEDS_REC,
6703	.parse			= event_hist_trigger_parse,
6704	.reg			= hist_register_trigger,
6705	.unreg			= hist_unregister_trigger,
6706	.unreg_all		= hist_unreg_all,
6707	.get_trigger_ops	= event_hist_get_trigger_ops,
6708	.set_filter		= set_trigger_filter,
6709};
6710
6711__init int register_trigger_hist_cmd(void)
6712{
6713	int ret;
6714
6715	ret = register_event_command(&trigger_hist_cmd);
6716	WARN_ON(ret < 0);
6717
6718	return ret;
6719}
6720
6721static void
6722hist_enable_trigger(struct event_trigger_data *data,
6723		    struct trace_buffer *buffer,  void *rec,
6724		    struct ring_buffer_event *event)
6725{
6726	struct enable_trigger_data *enable_data = data->private_data;
6727	struct event_trigger_data *test;
6728
6729	list_for_each_entry_rcu(test, &enable_data->file->triggers, list,
6730				lockdep_is_held(&event_mutex)) {
6731		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6732			if (enable_data->enable)
6733				test->paused = false;
6734			else
6735				test->paused = true;
6736		}
6737	}
6738}
6739
6740static void
6741hist_enable_count_trigger(struct event_trigger_data *data,
6742			  struct trace_buffer *buffer,  void *rec,
6743			  struct ring_buffer_event *event)
6744{
6745	if (!data->count)
6746		return;
6747
6748	if (data->count != -1)
6749		(data->count)--;
6750
6751	hist_enable_trigger(data, buffer, rec, event);
6752}
6753
6754static struct event_trigger_ops hist_enable_trigger_ops = {
6755	.trigger		= hist_enable_trigger,
6756	.print			= event_enable_trigger_print,
6757	.init			= event_trigger_init,
6758	.free			= event_enable_trigger_free,
6759};
6760
6761static struct event_trigger_ops hist_enable_count_trigger_ops = {
6762	.trigger		= hist_enable_count_trigger,
6763	.print			= event_enable_trigger_print,
6764	.init			= event_trigger_init,
6765	.free			= event_enable_trigger_free,
6766};
6767
6768static struct event_trigger_ops hist_disable_trigger_ops = {
6769	.trigger		= hist_enable_trigger,
6770	.print			= event_enable_trigger_print,
6771	.init			= event_trigger_init,
6772	.free			= event_enable_trigger_free,
6773};
6774
6775static struct event_trigger_ops hist_disable_count_trigger_ops = {
6776	.trigger		= hist_enable_count_trigger,
6777	.print			= event_enable_trigger_print,
6778	.init			= event_trigger_init,
6779	.free			= event_enable_trigger_free,
6780};
6781
6782static struct event_trigger_ops *
6783hist_enable_get_trigger_ops(char *cmd, char *param)
6784{
6785	struct event_trigger_ops *ops;
6786	bool enable;
6787
6788	enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
6789
6790	if (enable)
6791		ops = param ? &hist_enable_count_trigger_ops :
6792			&hist_enable_trigger_ops;
6793	else
6794		ops = param ? &hist_disable_count_trigger_ops :
6795			&hist_disable_trigger_ops;
6796
6797	return ops;
6798}
6799
6800static void hist_enable_unreg_all(struct trace_event_file *file)
6801{
6802	struct event_trigger_data *test, *n;
6803
6804	list_for_each_entry_safe(test, n, &file->triggers, list) {
6805		if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
6806			list_del_rcu(&test->list);
6807			update_cond_flag(file);
6808			trace_event_trigger_enable_disable(file, 0);
6809			if (test->ops->free)
6810				test->ops->free(test);
6811		}
6812	}
6813}
6814
6815static struct event_command trigger_hist_enable_cmd = {
6816	.name			= ENABLE_HIST_STR,
6817	.trigger_type		= ETT_HIST_ENABLE,
6818	.parse			= event_enable_trigger_parse,
6819	.reg			= event_enable_register_trigger,
6820	.unreg			= event_enable_unregister_trigger,
6821	.unreg_all		= hist_enable_unreg_all,
6822	.get_trigger_ops	= hist_enable_get_trigger_ops,
6823	.set_filter		= set_trigger_filter,
6824};
6825
6826static struct event_command trigger_hist_disable_cmd = {
6827	.name			= DISABLE_HIST_STR,
6828	.trigger_type		= ETT_HIST_ENABLE,
6829	.parse			= event_enable_trigger_parse,
6830	.reg			= event_enable_register_trigger,
6831	.unreg			= event_enable_unregister_trigger,
6832	.unreg_all		= hist_enable_unreg_all,
6833	.get_trigger_ops	= hist_enable_get_trigger_ops,
6834	.set_filter		= set_trigger_filter,
6835};
6836
6837static __init void unregister_trigger_hist_enable_disable_cmds(void)
6838{
6839	unregister_event_command(&trigger_hist_enable_cmd);
6840	unregister_event_command(&trigger_hist_disable_cmd);
6841}
6842
6843__init int register_trigger_hist_enable_disable_cmds(void)
6844{
6845	int ret;
6846
6847	ret = register_event_command(&trigger_hist_enable_cmd);
6848	if (WARN_ON(ret < 0))
6849		return ret;
6850	ret = register_event_command(&trigger_hist_disable_cmd);
6851	if (WARN_ON(ret < 0))
6852		unregister_trigger_hist_enable_disable_cmds();
6853
6854	return ret;
6855}