xref: /linux/kernel/trace/trace_events_hist.c (revision 7f711e62355bb3123a2ca2f97a2facbfebc678c6)
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/seq_buf.h>
12 #include <linux/mutex.h>
13 #include <linux/slab.h>
14 #include <linux/stacktrace.h>
15 #include <linux/rculist.h>
16 #include <linux/tracefs.h>
17 
18 /* for gfp flag names */
19 #include <linux/trace_events.h>
20 #include <trace/events/mmflags.h>
21 
22 #include "tracing_map.h"
23 #include "trace_synth.h"
24 
25 #define ERRORS								\
26 	C(NONE,			"No error"),				\
27 	C(DUPLICATE_VAR,	"Variable already defined"),		\
28 	C(VAR_NOT_UNIQUE,	"Variable name not unique, need to use fully qualified name (subsys.event.var) for variable"), \
29 	C(TOO_MANY_VARS,	"Too many variables defined"),		\
30 	C(MALFORMED_ASSIGNMENT,	"Malformed assignment"),		\
31 	C(NAMED_MISMATCH,	"Named hist trigger doesn't match existing named trigger (includes variables)"), \
32 	C(TRIGGER_EEXIST,	"Hist trigger already exists"),		\
33 	C(TRIGGER_ENOENT_CLEAR,	"Can't clear or continue a nonexistent hist trigger"), \
34 	C(SET_CLOCK_FAIL,	"Couldn't set trace_clock"),		\
35 	C(BAD_FIELD_MODIFIER,	"Invalid field modifier"),		\
36 	C(TOO_MANY_SUBEXPR,	"Too many subexpressions (3 max)"),	\
37 	C(TIMESTAMP_MISMATCH,	"Timestamp units in expression don't match"), \
38 	C(TOO_MANY_FIELD_VARS,	"Too many field variables defined"),	\
39 	C(EVENT_FILE_NOT_FOUND,	"Event file not found"),		\
40 	C(HIST_NOT_FOUND,	"Matching event histogram not found"),	\
41 	C(HIST_CREATE_FAIL,	"Couldn't create histogram for field"),	\
42 	C(SYNTH_VAR_NOT_FOUND,	"Couldn't find synthetic variable"),	\
43 	C(SYNTH_EVENT_NOT_FOUND,"Couldn't find synthetic event"),	\
44 	C(SYNTH_TYPE_MISMATCH,	"Param type doesn't match synthetic event field type"), \
45 	C(SYNTH_COUNT_MISMATCH,	"Param count doesn't match synthetic event field count"), \
46 	C(FIELD_VAR_PARSE_FAIL,	"Couldn't parse field variable"),	\
47 	C(VAR_CREATE_FIND_FAIL,	"Couldn't create or find variable"),	\
48 	C(ONX_NOT_VAR,		"For onmax(x) or onchange(x), x must be a variable"), \
49 	C(ONX_VAR_NOT_FOUND,	"Couldn't find onmax or onchange variable"), \
50 	C(ONX_VAR_CREATE_FAIL,	"Couldn't create onmax or onchange variable"), \
51 	C(FIELD_VAR_CREATE_FAIL,"Couldn't create field variable"),	\
52 	C(TOO_MANY_PARAMS,	"Too many action params"),		\
53 	C(PARAM_NOT_FOUND,	"Couldn't find param"),			\
54 	C(INVALID_PARAM,	"Invalid action param"),		\
55 	C(ACTION_NOT_FOUND,	"No action found"),			\
56 	C(NO_SAVE_PARAMS,	"No params found for save()"),		\
57 	C(TOO_MANY_SAVE_ACTIONS,"Can't have more than one save() action per hist"), \
58 	C(ACTION_MISMATCH,	"Handler doesn't support action"),	\
59 	C(NO_CLOSING_PAREN,	"No closing paren found"),		\
60 	C(SUBSYS_NOT_FOUND,	"Missing subsystem"),			\
61 	C(INVALID_SUBSYS_EVENT,	"Invalid subsystem or event name"),	\
62 	C(INVALID_REF_KEY,	"Using variable references in keys not supported"), \
63 	C(VAR_NOT_FOUND,	"Couldn't find variable"),		\
64 	C(FIELD_NOT_FOUND,	"Couldn't find field"),			\
65 	C(EMPTY_ASSIGNMENT,	"Empty assignment"),			\
66 	C(INVALID_SORT_MODIFIER,"Invalid sort modifier"),		\
67 	C(EMPTY_SORT_FIELD,	"Empty sort field"),			\
68 	C(TOO_MANY_SORT_FIELDS,	"Too many sort fields (Max = 2)"),	\
69 	C(INVALID_SORT_FIELD,	"Sort field must be a key or a val"),	\
70 	C(INVALID_STR_OPERAND,	"String type can not be an operand in expression"), \
71 	C(EXPECT_NUMBER,	"Expecting numeric literal"),		\
72 	C(UNARY_MINUS_SUBEXPR,	"Unary minus not supported in sub-expressions"), \
73 	C(DIVISION_BY_ZERO,	"Division by zero"),			\
74 	C(NEED_NOHC_VAL,	"Non-hitcount value is required for 'nohitcount'"),
75 
76 #undef C
77 #define C(a, b)		HIST_ERR_##a
78 
79 enum { ERRORS };
80 
81 #undef C
82 #define C(a, b)		b
83 
84 static const char *err_text[] = { ERRORS };
85 
86 struct hist_field;
87 
88 typedef u64 (*hist_field_fn_t) (struct hist_field *field,
89 				struct tracing_map_elt *elt,
90 				struct trace_buffer *buffer,
91 				struct ring_buffer_event *rbe,
92 				void *event);
93 
94 #define HIST_FIELD_OPERANDS_MAX	2
95 #define HIST_FIELDS_MAX		(TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
96 #define HIST_ACTIONS_MAX	8
97 #define HIST_DIV_SHIFT		20  /* For optimizing division by constants */
98 
99 enum 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 
108 #define FIELD_FUNCS					\
109 	C(NOP,			"nop"),			\
110 	C(VAR_REF,		"var_ref"),		\
111 	C(COUNTER,		"counter"),		\
112 	C(CONST,		"const"),		\
113 	C(LOG2,			"log2"),		\
114 	C(BUCKET,		"bucket"),		\
115 	C(TIMESTAMP,		"timestamp"),		\
116 	C(CPU,			"cpu"),			\
117 	C(COMM,			"comm"),		\
118 	C(STRING,		"string"),		\
119 	C(DYNSTRING,		"dynstring"),		\
120 	C(RELDYNSTRING,		"reldynstring"),	\
121 	C(PSTRING,		"pstring"),		\
122 	C(S64,			"s64"),			\
123 	C(U64,			"u64"),			\
124 	C(S32,			"s32"),			\
125 	C(U32,			"u32"),			\
126 	C(S16,			"s16"),			\
127 	C(U16,			"u16"),			\
128 	C(S8,			"s8"),			\
129 	C(U8,			"u8"),			\
130 	C(UMINUS,		"uminus"),		\
131 	C(MINUS,		"minus"),		\
132 	C(PLUS,			"plus"),		\
133 	C(DIV,			"div"),			\
134 	C(MULT,			"mult"),		\
135 	C(DIV_POWER2,		"div_power2"),		\
136 	C(DIV_NOT_POWER2,	"div_not_power2"),	\
137 	C(DIV_MULT_SHIFT,	"div_mult_shift"),	\
138 	C(EXECNAME,		"execname"),		\
139 	C(STACK,		"stack"),
140 
141 #undef C
142 #define C(a, b)		HIST_FIELD_FN_##a
143 
144 enum hist_field_fn {
145 	FIELD_FUNCS
146 };
147 
148 /*
149  * A hist_var (histogram variable) contains variable information for
150  * hist_fields having the HIST_FIELD_FL_VAR or HIST_FIELD_FL_VAR_REF
151  * flag set.  A hist_var has a variable name e.g. ts0, and is
152  * associated with a given histogram trigger, as specified by
153  * hist_data.  The hist_var idx is the unique index assigned to the
154  * variable by the hist trigger's tracing_map.  The idx is what is
155  * used to set a variable's value and, by a variable reference, to
156  * retrieve it.
157  */
158 struct hist_var {
159 	char				*name;
160 	struct hist_trigger_data	*hist_data;
161 	unsigned int			idx;
162 };
163 
164 struct hist_field {
165 	struct ftrace_event_field	*field;
166 	unsigned long			flags;
167 	unsigned long			buckets;
168 	const char			*type;
169 	struct hist_field		*operands[HIST_FIELD_OPERANDS_MAX];
170 	struct hist_trigger_data	*hist_data;
171 	enum hist_field_fn		fn_num;
172 	unsigned int			size;
173 	unsigned int			offset;
174 	unsigned int                    is_signed;
175 
176 	/*
177 	 * Variable fields contain variable-specific info in var.
178 	 */
179 	struct hist_var			var;
180 	enum field_op_id		operator;
181 	char				*system;
182 	char				*event_name;
183 
184 	/*
185 	 * The name field is used for EXPR and VAR_REF fields.  VAR
186 	 * fields contain the variable name in var.name.
187 	 */
188 	char				*name;
189 
190 	/*
191 	 * When a histogram trigger is hit, if it has any references
192 	 * to variables, the values of those variables are collected
193 	 * into a var_ref_vals array by resolve_var_refs().  The
194 	 * current value of each variable is read from the tracing_map
195 	 * using the hist field's hist_var.idx and entered into the
196 	 * var_ref_idx entry i.e. var_ref_vals[var_ref_idx].
197 	 */
198 	unsigned int			var_ref_idx;
199 	bool                            read_once;
200 
201 	unsigned int			var_str_idx;
202 
203 	/* Numeric literals are represented as u64 */
204 	u64				constant;
205 	/* Used to optimize division by constants */
206 	u64				div_multiplier;
207 };
208 
209 static u64 hist_fn_call(struct hist_field *hist_field,
210 			struct tracing_map_elt *elt,
211 			struct trace_buffer *buffer,
212 			struct ring_buffer_event *rbe,
213 			void *event);
214 
215 static u64 hist_field_const(struct hist_field *field,
216 			   struct tracing_map_elt *elt,
217 			   struct trace_buffer *buffer,
218 			   struct ring_buffer_event *rbe,
219 			   void *event)
220 {
221 	return field->constant;
222 }
223 
224 static u64 hist_field_counter(struct hist_field *field,
225 			      struct tracing_map_elt *elt,
226 			      struct trace_buffer *buffer,
227 			      struct ring_buffer_event *rbe,
228 			      void *event)
229 {
230 	return 1;
231 }
232 
233 static u64 hist_field_string(struct hist_field *hist_field,
234 			     struct tracing_map_elt *elt,
235 			     struct trace_buffer *buffer,
236 			     struct ring_buffer_event *rbe,
237 			     void *event)
238 {
239 	char *addr = (char *)(event + hist_field->field->offset);
240 
241 	return (u64)(unsigned long)addr;
242 }
243 
244 static u64 hist_field_dynstring(struct hist_field *hist_field,
245 				struct tracing_map_elt *elt,
246 				struct trace_buffer *buffer,
247 				struct ring_buffer_event *rbe,
248 				void *event)
249 {
250 	u32 str_item = *(u32 *)(event + hist_field->field->offset);
251 	int str_loc = str_item & 0xffff;
252 	char *addr = (char *)(event + str_loc);
253 
254 	return (u64)(unsigned long)addr;
255 }
256 
257 static u64 hist_field_reldynstring(struct hist_field *hist_field,
258 				   struct tracing_map_elt *elt,
259 				   struct trace_buffer *buffer,
260 				   struct ring_buffer_event *rbe,
261 				   void *event)
262 {
263 	u32 *item = event + hist_field->field->offset;
264 	u32 str_item = *item;
265 	int str_loc = str_item & 0xffff;
266 	char *addr = (char *)&item[1] + str_loc;
267 
268 	return (u64)(unsigned long)addr;
269 }
270 
271 static u64 hist_field_pstring(struct hist_field *hist_field,
272 			      struct tracing_map_elt *elt,
273 			      struct trace_buffer *buffer,
274 			      struct ring_buffer_event *rbe,
275 			      void *event)
276 {
277 	char **addr = (char **)(event + hist_field->field->offset);
278 
279 	return (u64)(unsigned long)*addr;
280 }
281 
282 static u64 hist_field_log2(struct hist_field *hist_field,
283 			   struct tracing_map_elt *elt,
284 			   struct trace_buffer *buffer,
285 			   struct ring_buffer_event *rbe,
286 			   void *event)
287 {
288 	struct hist_field *operand = hist_field->operands[0];
289 
290 	u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
291 
292 	return (u64) ilog2(roundup_pow_of_two(val));
293 }
294 
295 static u64 hist_field_bucket(struct hist_field *hist_field,
296 			     struct tracing_map_elt *elt,
297 			     struct trace_buffer *buffer,
298 			     struct ring_buffer_event *rbe,
299 			     void *event)
300 {
301 	struct hist_field *operand = hist_field->operands[0];
302 	unsigned long buckets = hist_field->buckets;
303 
304 	u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
305 
306 	if (WARN_ON_ONCE(!buckets))
307 		return val;
308 
309 	if (val >= LONG_MAX)
310 		val = div64_ul(val, buckets);
311 	else
312 		val = (u64)((unsigned long)val / buckets);
313 	return val * buckets;
314 }
315 
316 static u64 hist_field_plus(struct hist_field *hist_field,
317 			   struct tracing_map_elt *elt,
318 			   struct trace_buffer *buffer,
319 			   struct ring_buffer_event *rbe,
320 			   void *event)
321 {
322 	struct hist_field *operand1 = hist_field->operands[0];
323 	struct hist_field *operand2 = hist_field->operands[1];
324 
325 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
326 	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
327 
328 	return val1 + val2;
329 }
330 
331 static u64 hist_field_minus(struct hist_field *hist_field,
332 			    struct tracing_map_elt *elt,
333 			    struct trace_buffer *buffer,
334 			    struct ring_buffer_event *rbe,
335 			    void *event)
336 {
337 	struct hist_field *operand1 = hist_field->operands[0];
338 	struct hist_field *operand2 = hist_field->operands[1];
339 
340 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
341 	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
342 
343 	return val1 - val2;
344 }
345 
346 static u64 hist_field_div(struct hist_field *hist_field,
347 			   struct tracing_map_elt *elt,
348 			   struct trace_buffer *buffer,
349 			   struct ring_buffer_event *rbe,
350 			   void *event)
351 {
352 	struct hist_field *operand1 = hist_field->operands[0];
353 	struct hist_field *operand2 = hist_field->operands[1];
354 
355 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
356 	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
357 
358 	/* Return -1 for the undefined case */
359 	if (!val2)
360 		return -1;
361 
362 	/* Use shift if the divisor is a power of 2 */
363 	if (!(val2 & (val2 - 1)))
364 		return val1 >> __ffs64(val2);
365 
366 	return div64_u64(val1, val2);
367 }
368 
369 static u64 div_by_power_of_two(struct hist_field *hist_field,
370 				struct tracing_map_elt *elt,
371 				struct trace_buffer *buffer,
372 				struct ring_buffer_event *rbe,
373 				void *event)
374 {
375 	struct hist_field *operand1 = hist_field->operands[0];
376 	struct hist_field *operand2 = hist_field->operands[1];
377 
378 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
379 
380 	return val1 >> __ffs64(operand2->constant);
381 }
382 
383 static u64 div_by_not_power_of_two(struct hist_field *hist_field,
384 				struct tracing_map_elt *elt,
385 				struct trace_buffer *buffer,
386 				struct ring_buffer_event *rbe,
387 				void *event)
388 {
389 	struct hist_field *operand1 = hist_field->operands[0];
390 	struct hist_field *operand2 = hist_field->operands[1];
391 
392 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
393 
394 	return div64_u64(val1, operand2->constant);
395 }
396 
397 static u64 div_by_mult_and_shift(struct hist_field *hist_field,
398 				struct tracing_map_elt *elt,
399 				struct trace_buffer *buffer,
400 				struct ring_buffer_event *rbe,
401 				void *event)
402 {
403 	struct hist_field *operand1 = hist_field->operands[0];
404 	struct hist_field *operand2 = hist_field->operands[1];
405 
406 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
407 
408 	/*
409 	 * If the divisor is a constant, do a multiplication and shift instead.
410 	 *
411 	 * Choose Z = some power of 2. If Y <= Z, then:
412 	 *     X / Y = (X * (Z / Y)) / Z
413 	 *
414 	 * (Z / Y) is a constant (mult) which is calculated at parse time, so:
415 	 *     X / Y = (X * mult) / Z
416 	 *
417 	 * The division by Z can be replaced by a shift since Z is a power of 2:
418 	 *     X / Y = (X * mult) >> HIST_DIV_SHIFT
419 	 *
420 	 * As long, as X < Z the results will not be off by more than 1.
421 	 */
422 	if (val1 < (1 << HIST_DIV_SHIFT)) {
423 		u64 mult = operand2->div_multiplier;
424 
425 		return (val1 * mult + ((1 << HIST_DIV_SHIFT) - 1)) >> HIST_DIV_SHIFT;
426 	}
427 
428 	return div64_u64(val1, operand2->constant);
429 }
430 
431 static u64 hist_field_mult(struct hist_field *hist_field,
432 			   struct tracing_map_elt *elt,
433 			   struct trace_buffer *buffer,
434 			   struct ring_buffer_event *rbe,
435 			   void *event)
436 {
437 	struct hist_field *operand1 = hist_field->operands[0];
438 	struct hist_field *operand2 = hist_field->operands[1];
439 
440 	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
441 	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
442 
443 	return val1 * val2;
444 }
445 
446 static u64 hist_field_unary_minus(struct hist_field *hist_field,
447 				  struct tracing_map_elt *elt,
448 				  struct trace_buffer *buffer,
449 				  struct ring_buffer_event *rbe,
450 				  void *event)
451 {
452 	struct hist_field *operand = hist_field->operands[0];
453 
454 	s64 sval = (s64)hist_fn_call(operand, elt, buffer, rbe, event);
455 	u64 val = (u64)-sval;
456 
457 	return val;
458 }
459 
460 #define DEFINE_HIST_FIELD_FN(type)					\
461 	static u64 hist_field_##type(struct hist_field *hist_field,	\
462 				     struct tracing_map_elt *elt,	\
463 				     struct trace_buffer *buffer,	\
464 				     struct ring_buffer_event *rbe,	\
465 				     void *event)			\
466 {									\
467 	type *addr = (type *)(event + hist_field->field->offset);	\
468 									\
469 	return (u64)(unsigned long)*addr;				\
470 }
471 
472 DEFINE_HIST_FIELD_FN(s64);
473 DEFINE_HIST_FIELD_FN(u64);
474 DEFINE_HIST_FIELD_FN(s32);
475 DEFINE_HIST_FIELD_FN(u32);
476 DEFINE_HIST_FIELD_FN(s16);
477 DEFINE_HIST_FIELD_FN(u16);
478 DEFINE_HIST_FIELD_FN(s8);
479 DEFINE_HIST_FIELD_FN(u8);
480 
481 #define for_each_hist_field(i, hist_data)	\
482 	for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
483 
484 #define for_each_hist_val_field(i, hist_data)	\
485 	for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
486 
487 #define for_each_hist_key_field(i, hist_data)	\
488 	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
489 
490 #define HITCOUNT_IDX		0
491 #define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
492 
493 enum hist_field_flags {
494 	HIST_FIELD_FL_HITCOUNT		= 1 << 0,
495 	HIST_FIELD_FL_KEY		= 1 << 1,
496 	HIST_FIELD_FL_STRING		= 1 << 2,
497 	HIST_FIELD_FL_HEX		= 1 << 3,
498 	HIST_FIELD_FL_SYM		= 1 << 4,
499 	HIST_FIELD_FL_SYM_OFFSET	= 1 << 5,
500 	HIST_FIELD_FL_EXECNAME		= 1 << 6,
501 	HIST_FIELD_FL_SYSCALL		= 1 << 7,
502 	HIST_FIELD_FL_STACKTRACE	= 1 << 8,
503 	HIST_FIELD_FL_LOG2		= 1 << 9,
504 	HIST_FIELD_FL_TIMESTAMP		= 1 << 10,
505 	HIST_FIELD_FL_TIMESTAMP_USECS	= 1 << 11,
506 	HIST_FIELD_FL_VAR		= 1 << 12,
507 	HIST_FIELD_FL_EXPR		= 1 << 13,
508 	HIST_FIELD_FL_VAR_REF		= 1 << 14,
509 	HIST_FIELD_FL_CPU		= 1 << 15,
510 	HIST_FIELD_FL_ALIAS		= 1 << 16,
511 	HIST_FIELD_FL_BUCKET		= 1 << 17,
512 	HIST_FIELD_FL_CONST		= 1 << 18,
513 	HIST_FIELD_FL_PERCENT		= 1 << 19,
514 	HIST_FIELD_FL_GRAPH		= 1 << 20,
515 	HIST_FIELD_FL_COMM		= 1 << 21,
516 };
517 
518 struct var_defs {
519 	unsigned int	n_vars;
520 	char		*name[TRACING_MAP_VARS_MAX];
521 	char		*expr[TRACING_MAP_VARS_MAX];
522 };
523 
524 struct hist_trigger_attrs {
525 	char		*keys_str;
526 	char		*vals_str;
527 	char		*sort_key_str;
528 	char		*name;
529 	char		*clock;
530 	bool		pause;
531 	bool		cont;
532 	bool		clear;
533 	bool		ts_in_usecs;
534 	bool		no_hitcount;
535 	unsigned int	map_bits;
536 
537 	char		*assignment_str[TRACING_MAP_VARS_MAX];
538 	unsigned int	n_assignments;
539 
540 	char		*action_str[HIST_ACTIONS_MAX];
541 	unsigned int	n_actions;
542 
543 	struct var_defs	var_defs;
544 };
545 
546 struct field_var {
547 	struct hist_field	*var;
548 	struct hist_field	*val;
549 };
550 
551 struct field_var_hist {
552 	struct hist_trigger_data	*hist_data;
553 	char				*cmd;
554 };
555 
556 struct hist_trigger_data {
557 	struct hist_field               *fields[HIST_FIELDS_MAX];
558 	unsigned int			n_vals;
559 	unsigned int			n_keys;
560 	unsigned int			n_fields;
561 	unsigned int			n_vars;
562 	unsigned int			n_var_str;
563 	unsigned int			key_size;
564 	struct tracing_map_sort_key	sort_keys[TRACING_MAP_SORT_KEYS_MAX];
565 	unsigned int			n_sort_keys;
566 	struct trace_event_file		*event_file;
567 	struct hist_trigger_attrs	*attrs;
568 	struct tracing_map		*map;
569 	bool				enable_timestamps;
570 	bool				remove;
571 	struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
572 	unsigned int			n_var_refs;
573 
574 	struct action_data		*actions[HIST_ACTIONS_MAX];
575 	unsigned int			n_actions;
576 
577 	struct field_var		*field_vars[SYNTH_FIELDS_MAX];
578 	unsigned int			n_field_vars;
579 	unsigned int			n_field_var_str;
580 	struct field_var_hist		*field_var_hists[SYNTH_FIELDS_MAX];
581 	unsigned int			n_field_var_hists;
582 
583 	struct field_var		*save_vars[SYNTH_FIELDS_MAX];
584 	unsigned int			n_save_vars;
585 	unsigned int			n_save_var_str;
586 };
587 
588 struct action_data;
589 
590 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
591 			     struct tracing_map_elt *elt,
592 			     struct trace_buffer *buffer, void *rec,
593 			     struct ring_buffer_event *rbe, void *key,
594 			     struct action_data *data, u64 *var_ref_vals);
595 
596 typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
597 
598 enum handler_id {
599 	HANDLER_ONMATCH = 1,
600 	HANDLER_ONMAX,
601 	HANDLER_ONCHANGE,
602 };
603 
604 enum action_id {
605 	ACTION_SAVE = 1,
606 	ACTION_TRACE,
607 	ACTION_SNAPSHOT,
608 };
609 
610 struct action_data {
611 	enum handler_id		handler;
612 	enum action_id		action;
613 	char			*action_name;
614 	action_fn_t		fn;
615 
616 	unsigned int		n_params;
617 	char			*params[SYNTH_FIELDS_MAX];
618 
619 	/*
620 	 * When a histogram trigger is hit, the values of any
621 	 * references to variables, including variables being passed
622 	 * as parameters to synthetic events, are collected into a
623 	 * var_ref_vals array.  This var_ref_idx array is an array of
624 	 * indices into the var_ref_vals array, one for each synthetic
625 	 * event param, and is passed to the synthetic event
626 	 * invocation.
627 	 */
628 	unsigned int		var_ref_idx[SYNTH_FIELDS_MAX];
629 	struct synth_event	*synth_event;
630 	bool			use_trace_keyword;
631 	char			*synth_event_name;
632 
633 	union {
634 		struct {
635 			char			*event;
636 			char			*event_system;
637 		} match_data;
638 
639 		struct {
640 			/*
641 			 * var_str contains the $-unstripped variable
642 			 * name referenced by var_ref, and used when
643 			 * printing the action.  Because var_ref
644 			 * creation is deferred to create_actions(),
645 			 * we need a per-action way to save it until
646 			 * then, thus var_str.
647 			 */
648 			char			*var_str;
649 
650 			/*
651 			 * var_ref refers to the variable being
652 			 * tracked e.g onmax($var).
653 			 */
654 			struct hist_field	*var_ref;
655 
656 			/*
657 			 * track_var contains the 'invisible' tracking
658 			 * variable created to keep the current
659 			 * e.g. max value.
660 			 */
661 			struct hist_field	*track_var;
662 
663 			check_track_val_fn_t	check_val;
664 			action_fn_t		save_data;
665 		} track_data;
666 	};
667 };
668 
669 struct track_data {
670 	u64				track_val;
671 	bool				updated;
672 
673 	unsigned int			key_len;
674 	void				*key;
675 	struct tracing_map_elt		elt;
676 
677 	struct action_data		*action_data;
678 	struct hist_trigger_data	*hist_data;
679 };
680 
681 struct hist_elt_data {
682 	char *comm;
683 	u64 *var_ref_vals;
684 	int n_field_var_str;
685 	char *field_var_str[] __counted_by(n_field_var_str);
686 };
687 
688 struct snapshot_context {
689 	struct tracing_map_elt	*elt;
690 	void			*key;
691 };
692 
693 /*
694  * Returns the specific division function to use if the divisor
695  * is constant. This avoids extra branches when the trigger is hit.
696  */
697 static enum hist_field_fn hist_field_get_div_fn(struct hist_field *divisor)
698 {
699 	u64 div = divisor->constant;
700 
701 	if (!(div & (div - 1)))
702 		return HIST_FIELD_FN_DIV_POWER2;
703 
704 	/* If the divisor is too large, do a regular division */
705 	if (div > (1 << HIST_DIV_SHIFT))
706 		return HIST_FIELD_FN_DIV_NOT_POWER2;
707 
708 	divisor->div_multiplier = div64_u64((u64)(1 << HIST_DIV_SHIFT), div);
709 	return HIST_FIELD_FN_DIV_MULT_SHIFT;
710 }
711 
712 static void track_data_free(struct track_data *track_data)
713 {
714 	struct hist_elt_data *elt_data;
715 
716 	if (!track_data)
717 		return;
718 
719 	kfree(track_data->key);
720 
721 	elt_data = track_data->elt.private_data;
722 	if (elt_data) {
723 		kfree(elt_data->comm);
724 		kfree(elt_data);
725 	}
726 
727 	kfree(track_data);
728 }
729 
730 static struct track_data *track_data_alloc(unsigned int key_len,
731 					   struct action_data *action_data,
732 					   struct hist_trigger_data *hist_data)
733 {
734 	struct track_data *data = kzalloc_obj(*data);
735 	struct hist_elt_data *elt_data;
736 
737 	if (!data)
738 		return ERR_PTR(-ENOMEM);
739 
740 	data->key = kzalloc(key_len, GFP_KERNEL);
741 	if (!data->key) {
742 		track_data_free(data);
743 		return ERR_PTR(-ENOMEM);
744 	}
745 
746 	data->key_len = key_len;
747 	data->action_data = action_data;
748 	data->hist_data = hist_data;
749 
750 	elt_data = kzalloc_obj(*elt_data);
751 	if (!elt_data) {
752 		track_data_free(data);
753 		return ERR_PTR(-ENOMEM);
754 	}
755 
756 	data->elt.private_data = elt_data;
757 
758 	elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
759 	if (!elt_data->comm) {
760 		track_data_free(data);
761 		return ERR_PTR(-ENOMEM);
762 	}
763 
764 	return data;
765 }
766 
767 #define HIST_PREFIX "hist:"
768 
769 static char *last_cmd;
770 static char last_cmd_loc[MAX_FILTER_STR_VAL];
771 
772 static int errpos(char *str)
773 {
774 	if (!str || !last_cmd)
775 		return 0;
776 
777 	return err_pos(last_cmd, str);
778 }
779 
780 static void last_cmd_set(struct trace_event_file *file, char *str)
781 {
782 	const char *system = NULL, *name = NULL;
783 	struct trace_event_call *call;
784 
785 	if (!str)
786 		return;
787 
788 	kfree(last_cmd);
789 
790 	last_cmd = kasprintf(GFP_KERNEL, HIST_PREFIX "%s", str);
791 	if (!last_cmd)
792 		return;
793 
794 	if (file) {
795 		call = file->event_call;
796 		system = call->class->system;
797 		if (system) {
798 			name = trace_event_name(call);
799 			if (!name)
800 				system = NULL;
801 		}
802 	}
803 
804 	if (system)
805 		snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name);
806 }
807 
808 static void hist_err(struct trace_array *tr, u8 err_type, u16 err_pos)
809 {
810 	if (!last_cmd)
811 		return;
812 
813 	tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
814 			err_type, err_pos);
815 }
816 
817 static void hist_err_clear(void)
818 {
819 	if (last_cmd)
820 		last_cmd[0] = '\0';
821 	last_cmd_loc[0] = '\0';
822 }
823 
824 typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
825 				    unsigned int *var_ref_idx);
826 
827 static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
828 			       unsigned int *var_ref_idx)
829 {
830 	struct tracepoint *tp = event->tp;
831 
832 	if (unlikely(static_key_enabled(&tp->key))) {
833 		struct tracepoint_func *probe_func_ptr;
834 		synth_probe_func_t probe_func;
835 		void *__data;
836 
837 		if (!(cpu_online(raw_smp_processor_id())))
838 			return;
839 
840 		probe_func_ptr = rcu_dereference_sched((tp)->funcs);
841 		if (probe_func_ptr) {
842 			do {
843 				probe_func = probe_func_ptr->func;
844 				__data = probe_func_ptr->data;
845 				probe_func(__data, var_ref_vals, var_ref_idx);
846 			} while ((++probe_func_ptr)->func);
847 		}
848 	}
849 }
850 
851 static void action_trace(struct hist_trigger_data *hist_data,
852 			 struct tracing_map_elt *elt,
853 			 struct trace_buffer *buffer, void *rec,
854 			 struct ring_buffer_event *rbe, void *key,
855 			 struct action_data *data, u64 *var_ref_vals)
856 {
857 	struct synth_event *event = data->synth_event;
858 
859 	trace_synth(event, var_ref_vals, data->var_ref_idx);
860 }
861 
862 struct hist_var_data {
863 	struct list_head list;
864 	struct hist_trigger_data *hist_data;
865 };
866 
867 static u64 hist_field_timestamp(struct hist_field *hist_field,
868 				struct tracing_map_elt *elt,
869 				struct trace_buffer *buffer,
870 				struct ring_buffer_event *rbe,
871 				void *event)
872 {
873 	struct hist_trigger_data *hist_data = hist_field->hist_data;
874 	struct trace_array *tr = hist_data->event_file->tr;
875 
876 	u64 ts = ring_buffer_event_time_stamp(buffer, rbe);
877 
878 	if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
879 		ts = ns2usecs(ts);
880 
881 	return ts;
882 }
883 
884 static u64 hist_field_cpu(struct hist_field *hist_field,
885 			  struct tracing_map_elt *elt,
886 			  struct trace_buffer *buffer,
887 			  struct ring_buffer_event *rbe,
888 			  void *event)
889 {
890 	int cpu = smp_processor_id();
891 
892 	return cpu;
893 }
894 
895 static u64 hist_field_comm(struct hist_field *hist_field,
896 			  struct tracing_map_elt *elt,
897 			  struct trace_buffer *buffer,
898 			  struct ring_buffer_event *rbe,
899 			  void *event)
900 {
901 	return (u64)(unsigned long)current->comm;
902 }
903 
904 /**
905  * check_field_for_var_ref - Check if a VAR_REF field references a variable
906  * @hist_field: The VAR_REF field to check
907  * @var_data: The hist trigger that owns the variable
908  * @var_idx: The trigger variable identifier
909  *
910  * Check the given VAR_REF field to see whether or not it references
911  * the given variable associated with the given trigger.
912  *
913  * Return: The VAR_REF field if it does reference the variable, NULL if not
914  */
915 static struct hist_field *
916 check_field_for_var_ref(struct hist_field *hist_field,
917 			struct hist_trigger_data *var_data,
918 			unsigned int var_idx)
919 {
920 	WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));
921 
922 	if (hist_field && hist_field->var.idx == var_idx &&
923 	    hist_field->var.hist_data == var_data)
924 		return hist_field;
925 
926 	return NULL;
927 }
928 
929 /**
930  * find_var_ref - Check if a trigger has a reference to a trigger variable
931  * @hist_data: The hist trigger that might have a reference to the variable
932  * @var_data: The hist trigger that owns the variable
933  * @var_idx: The trigger variable identifier
934  *
935  * Check the list of var_refs[] on the first hist trigger to see
936  * whether any of them are references to the variable on the second
937  * trigger.
938  *
939  * Return: The VAR_REF field referencing the variable if so, NULL if not
940  */
941 static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
942 				       struct hist_trigger_data *var_data,
943 				       unsigned int var_idx)
944 {
945 	struct hist_field *hist_field;
946 	unsigned int i;
947 
948 	for (i = 0; i < hist_data->n_var_refs; i++) {
949 		hist_field = hist_data->var_refs[i];
950 		if (check_field_for_var_ref(hist_field, var_data, var_idx))
951 			return hist_field;
952 	}
953 
954 	return NULL;
955 }
956 
957 /**
958  * find_any_var_ref - Check if there is a reference to a given trigger variable
959  * @hist_data: The hist trigger
960  * @var_idx: The trigger variable identifier
961  *
962  * Check to see whether the given variable is currently referenced by
963  * any other trigger.
964  *
965  * The trigger the variable is defined on is explicitly excluded - the
966  * assumption being that a self-reference doesn't prevent a trigger
967  * from being removed.
968  *
969  * Return: The VAR_REF field referencing the variable if so, NULL if not
970  */
971 static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
972 					   unsigned int var_idx)
973 {
974 	struct trace_array *tr = hist_data->event_file->tr;
975 	struct hist_field *found = NULL;
976 	struct hist_var_data *var_data;
977 
978 	list_for_each_entry(var_data, &tr->hist_vars, list) {
979 		if (var_data->hist_data == hist_data)
980 			continue;
981 		found = find_var_ref(var_data->hist_data, hist_data, var_idx);
982 		if (found)
983 			break;
984 	}
985 
986 	return found;
987 }
988 
989 /**
990  * check_var_refs - Check if there is a reference to any of trigger's variables
991  * @hist_data: The hist trigger
992  *
993  * A trigger can define one or more variables.  If any one of them is
994  * currently referenced by any other trigger, this function will
995  * determine that.
996  *
997  * Typically used to determine whether or not a trigger can be removed
998  * - if there are any references to a trigger's variables, it cannot.
999  *
1000  * Return: True if there is a reference to any of trigger's variables
1001  */
1002 static bool check_var_refs(struct hist_trigger_data *hist_data)
1003 {
1004 	struct hist_field *field;
1005 	bool found = false;
1006 	int i;
1007 
1008 	for_each_hist_field(i, hist_data) {
1009 		field = hist_data->fields[i];
1010 		if (field && field->flags & HIST_FIELD_FL_VAR) {
1011 			if (find_any_var_ref(hist_data, field->var.idx)) {
1012 				found = true;
1013 				break;
1014 			}
1015 		}
1016 	}
1017 
1018 	return found;
1019 }
1020 
1021 static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
1022 {
1023 	struct trace_array *tr = hist_data->event_file->tr;
1024 	struct hist_var_data *var_data, *found = NULL;
1025 
1026 	list_for_each_entry(var_data, &tr->hist_vars, list) {
1027 		if (var_data->hist_data == hist_data) {
1028 			found = var_data;
1029 			break;
1030 		}
1031 	}
1032 
1033 	return found;
1034 }
1035 
1036 static bool field_has_hist_vars(struct hist_field *hist_field,
1037 				unsigned int level)
1038 {
1039 	int i;
1040 
1041 	if (level > 3)
1042 		return false;
1043 
1044 	if (!hist_field)
1045 		return false;
1046 
1047 	if (hist_field->flags & HIST_FIELD_FL_VAR ||
1048 	    hist_field->flags & HIST_FIELD_FL_VAR_REF)
1049 		return true;
1050 
1051 	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
1052 		struct hist_field *operand;
1053 
1054 		operand = hist_field->operands[i];
1055 		if (field_has_hist_vars(operand, level + 1))
1056 			return true;
1057 	}
1058 
1059 	return false;
1060 }
1061 
1062 static bool has_hist_vars(struct hist_trigger_data *hist_data)
1063 {
1064 	struct hist_field *hist_field;
1065 	int i;
1066 
1067 	for_each_hist_field(i, hist_data) {
1068 		hist_field = hist_data->fields[i];
1069 		if (field_has_hist_vars(hist_field, 0))
1070 			return true;
1071 	}
1072 
1073 	return false;
1074 }
1075 
1076 static int save_hist_vars(struct hist_trigger_data *hist_data)
1077 {
1078 	struct trace_array *tr = hist_data->event_file->tr;
1079 	struct hist_var_data *var_data;
1080 
1081 	var_data = find_hist_vars(hist_data);
1082 	if (var_data)
1083 		return 0;
1084 
1085 	if (tracing_check_open_get_tr(tr))
1086 		return -ENODEV;
1087 
1088 	var_data = kzalloc_obj(*var_data);
1089 	if (!var_data) {
1090 		trace_array_put(tr);
1091 		return -ENOMEM;
1092 	}
1093 
1094 	var_data->hist_data = hist_data;
1095 	list_add(&var_data->list, &tr->hist_vars);
1096 
1097 	return 0;
1098 }
1099 
1100 static void remove_hist_vars(struct hist_trigger_data *hist_data)
1101 {
1102 	struct trace_array *tr = hist_data->event_file->tr;
1103 	struct hist_var_data *var_data;
1104 
1105 	var_data = find_hist_vars(hist_data);
1106 	if (!var_data)
1107 		return;
1108 
1109 	if (WARN_ON(check_var_refs(hist_data)))
1110 		return;
1111 
1112 	list_del(&var_data->list);
1113 
1114 	kfree(var_data);
1115 
1116 	trace_array_put(tr);
1117 }
1118 
1119 static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
1120 					 const char *var_name)
1121 {
1122 	struct hist_field *hist_field, *found = NULL;
1123 	int i;
1124 
1125 	for_each_hist_field(i, hist_data) {
1126 		hist_field = hist_data->fields[i];
1127 		if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
1128 		    strcmp(hist_field->var.name, var_name) == 0) {
1129 			found = hist_field;
1130 			break;
1131 		}
1132 	}
1133 
1134 	return found;
1135 }
1136 
1137 static struct hist_field *find_var(struct hist_trigger_data *hist_data,
1138 				   struct trace_event_file *file,
1139 				   const char *var_name)
1140 {
1141 	struct hist_trigger_data *test_data;
1142 	struct event_trigger_data *test;
1143 	struct hist_field *hist_field;
1144 
1145 	lockdep_assert_held(&event_mutex);
1146 
1147 	hist_field = find_var_field(hist_data, var_name);
1148 	if (hist_field)
1149 		return hist_field;
1150 
1151 	list_for_each_entry(test, &file->triggers, list) {
1152 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1153 			test_data = test->private_data;
1154 			hist_field = find_var_field(test_data, var_name);
1155 			if (hist_field)
1156 				return hist_field;
1157 		}
1158 	}
1159 
1160 	return NULL;
1161 }
1162 
1163 static struct trace_event_file *find_var_file(struct trace_array *tr,
1164 					      char *system,
1165 					      char *event_name,
1166 					      char *var_name)
1167 {
1168 	struct hist_trigger_data *var_hist_data;
1169 	struct hist_var_data *var_data;
1170 	struct trace_event_file *file, *found = NULL;
1171 
1172 	if (system)
1173 		return find_event_file(tr, system, event_name);
1174 
1175 	list_for_each_entry(var_data, &tr->hist_vars, list) {
1176 		var_hist_data = var_data->hist_data;
1177 		file = var_hist_data->event_file;
1178 		if (file == found)
1179 			continue;
1180 
1181 		if (find_var_field(var_hist_data, var_name)) {
1182 			if (found) {
1183 				hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE, errpos(var_name));
1184 				return NULL;
1185 			}
1186 
1187 			found = file;
1188 		}
1189 	}
1190 
1191 	return found;
1192 }
1193 
1194 static struct hist_field *find_file_var(struct trace_event_file *file,
1195 					const char *var_name)
1196 {
1197 	struct hist_trigger_data *test_data;
1198 	struct event_trigger_data *test;
1199 	struct hist_field *hist_field;
1200 
1201 	lockdep_assert_held(&event_mutex);
1202 
1203 	list_for_each_entry(test, &file->triggers, list) {
1204 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
1205 			test_data = test->private_data;
1206 			hist_field = find_var_field(test_data, var_name);
1207 			if (hist_field)
1208 				return hist_field;
1209 		}
1210 	}
1211 
1212 	return NULL;
1213 }
1214 
1215 static struct hist_field *
1216 find_match_var(struct hist_trigger_data *hist_data, char *var_name)
1217 {
1218 	struct trace_array *tr = hist_data->event_file->tr;
1219 	struct hist_field *hist_field, *found = NULL;
1220 	struct trace_event_file *file;
1221 	unsigned int i;
1222 
1223 	for (i = 0; i < hist_data->n_actions; i++) {
1224 		struct action_data *data = hist_data->actions[i];
1225 
1226 		if (data->handler == HANDLER_ONMATCH) {
1227 			char *system = data->match_data.event_system;
1228 			char *event_name = data->match_data.event;
1229 
1230 			file = find_var_file(tr, system, event_name, var_name);
1231 			if (!file)
1232 				continue;
1233 			hist_field = find_file_var(file, var_name);
1234 			if (hist_field) {
1235 				if (found) {
1236 					hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE,
1237 						 errpos(var_name));
1238 					return ERR_PTR(-EINVAL);
1239 				}
1240 
1241 				found = hist_field;
1242 			}
1243 		}
1244 	}
1245 	return found;
1246 }
1247 
1248 static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
1249 					 char *system,
1250 					 char *event_name,
1251 					 char *var_name)
1252 {
1253 	struct trace_array *tr = hist_data->event_file->tr;
1254 	struct hist_field *hist_field = NULL;
1255 	struct trace_event_file *file;
1256 
1257 	if (!system || !event_name) {
1258 		hist_field = find_match_var(hist_data, var_name);
1259 		if (IS_ERR(hist_field))
1260 			return NULL;
1261 		if (hist_field)
1262 			return hist_field;
1263 	}
1264 
1265 	file = find_var_file(tr, system, event_name, var_name);
1266 	if (!file)
1267 		return NULL;
1268 
1269 	hist_field = find_file_var(file, var_name);
1270 
1271 	return hist_field;
1272 }
1273 
1274 static u64 hist_field_var_ref(struct hist_field *hist_field,
1275 			      struct tracing_map_elt *elt,
1276 			      struct trace_buffer *buffer,
1277 			      struct ring_buffer_event *rbe,
1278 			      void *event)
1279 {
1280 	struct hist_elt_data *elt_data;
1281 	u64 var_val = 0;
1282 
1283 	if (WARN_ON_ONCE(!elt))
1284 		return var_val;
1285 
1286 	elt_data = elt->private_data;
1287 	var_val = elt_data->var_ref_vals[hist_field->var_ref_idx];
1288 
1289 	return var_val;
1290 }
1291 
1292 static bool resolve_var_refs(struct hist_trigger_data *hist_data, void *key,
1293 			     u64 *var_ref_vals, bool self)
1294 {
1295 	struct hist_trigger_data *var_data;
1296 	struct tracing_map_elt *var_elt;
1297 	struct hist_field *hist_field;
1298 	unsigned int i, var_idx;
1299 	bool resolved = true;
1300 	u64 var_val = 0;
1301 
1302 	for (i = 0; i < hist_data->n_var_refs; i++) {
1303 		hist_field = hist_data->var_refs[i];
1304 		var_idx = hist_field->var.idx;
1305 		var_data = hist_field->var.hist_data;
1306 
1307 		if (var_data == NULL) {
1308 			resolved = false;
1309 			break;
1310 		}
1311 
1312 		if ((self && var_data != hist_data) ||
1313 		    (!self && var_data == hist_data))
1314 			continue;
1315 
1316 		var_elt = tracing_map_lookup(var_data->map, key);
1317 		if (!var_elt) {
1318 			resolved = false;
1319 			break;
1320 		}
1321 
1322 		if (!tracing_map_var_set(var_elt, var_idx)) {
1323 			resolved = false;
1324 			break;
1325 		}
1326 
1327 		if (self || !hist_field->read_once)
1328 			var_val = tracing_map_read_var(var_elt, var_idx);
1329 		else
1330 			var_val = tracing_map_read_var_once(var_elt, var_idx);
1331 
1332 		var_ref_vals[i] = var_val;
1333 	}
1334 
1335 	return resolved;
1336 }
1337 
1338 static const char *hist_field_name(struct hist_field *field,
1339 				   unsigned int level)
1340 {
1341 	const char *field_name = "";
1342 
1343 	if (WARN_ON_ONCE(!field))
1344 		return field_name;
1345 
1346 	if (level > 1)
1347 		return field_name;
1348 
1349 	if (field->field)
1350 		field_name = field->field->name;
1351 	else if (field->flags & HIST_FIELD_FL_LOG2 ||
1352 		 field->flags & HIST_FIELD_FL_ALIAS ||
1353 		 field->flags & HIST_FIELD_FL_BUCKET)
1354 		field_name = hist_field_name(field->operands[0], ++level);
1355 	else if (field->flags & HIST_FIELD_FL_CPU)
1356 		field_name = "common_cpu";
1357 	else if (field->flags & HIST_FIELD_FL_COMM)
1358 		field_name = "common_comm";
1359 	else if (field->flags & HIST_FIELD_FL_EXPR ||
1360 		 field->flags & HIST_FIELD_FL_VAR_REF) {
1361 		if (field->system) {
1362 			static char full_name[MAX_FILTER_STR_VAL];
1363 			static char *fmt;
1364 			int len;
1365 
1366 			fmt = field->flags & HIST_FIELD_FL_VAR_REF ? "%s.%s.$%s" : "%s.%s.%s";
1367 
1368 			len = snprintf(full_name, sizeof(full_name), fmt,
1369 				       field->system, field->event_name,
1370 				       field->name);
1371 			if (len < sizeof(full_name))
1372 				field_name = full_name;
1373 		} else
1374 			field_name = field->name;
1375 	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
1376 		field_name = "common_timestamp";
1377 	else if (field->flags & HIST_FIELD_FL_STACKTRACE) {
1378 		field_name = "common_stacktrace";
1379 	} else if (field->flags & HIST_FIELD_FL_HITCOUNT)
1380 		field_name = "hitcount";
1381 
1382 	if (field_name == NULL)
1383 		field_name = "";
1384 
1385 	return field_name;
1386 }
1387 
1388 static enum hist_field_fn select_value_fn(int field_size, int field_is_signed)
1389 {
1390 	switch (field_size) {
1391 	case 8:
1392 		if (field_is_signed)
1393 			return HIST_FIELD_FN_S64;
1394 		else
1395 			return HIST_FIELD_FN_U64;
1396 	case 4:
1397 		if (field_is_signed)
1398 			return HIST_FIELD_FN_S32;
1399 		else
1400 			return HIST_FIELD_FN_U32;
1401 	case 2:
1402 		if (field_is_signed)
1403 			return HIST_FIELD_FN_S16;
1404 		else
1405 			return HIST_FIELD_FN_U16;
1406 	case 1:
1407 		if (field_is_signed)
1408 			return HIST_FIELD_FN_S8;
1409 		else
1410 			return HIST_FIELD_FN_U8;
1411 	}
1412 
1413 	return HIST_FIELD_FN_NOP;
1414 }
1415 
1416 static int parse_map_size(char *str)
1417 {
1418 	unsigned long size, map_bits;
1419 	int ret;
1420 
1421 	ret = kstrtoul(str, 0, &size);
1422 	if (ret)
1423 		goto out;
1424 
1425 	map_bits = ilog2(roundup_pow_of_two(size));
1426 	if (map_bits < TRACING_MAP_BITS_MIN ||
1427 	    map_bits > TRACING_MAP_BITS_MAX)
1428 		ret = -EINVAL;
1429 	else
1430 		ret = map_bits;
1431  out:
1432 	return ret;
1433 }
1434 
1435 static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
1436 {
1437 	unsigned int i;
1438 
1439 	if (!attrs)
1440 		return;
1441 
1442 	for (i = 0; i < attrs->n_assignments; i++)
1443 		kfree(attrs->assignment_str[i]);
1444 
1445 	for (i = 0; i < attrs->n_actions; i++)
1446 		kfree(attrs->action_str[i]);
1447 
1448 	kfree(attrs->name);
1449 	kfree(attrs->sort_key_str);
1450 	kfree(attrs->keys_str);
1451 	kfree(attrs->vals_str);
1452 	kfree(attrs->clock);
1453 	kfree(attrs);
1454 }
1455 
1456 static int parse_action(char *str, struct hist_trigger_attrs *attrs)
1457 {
1458 	int ret = -EINVAL;
1459 
1460 	if (attrs->n_actions >= HIST_ACTIONS_MAX)
1461 		return ret;
1462 
1463 	if ((str_has_prefix(str, "onmatch(")) ||
1464 	    (str_has_prefix(str, "onmax(")) ||
1465 	    (str_has_prefix(str, "onchange("))) {
1466 		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
1467 		if (!attrs->action_str[attrs->n_actions]) {
1468 			ret = -ENOMEM;
1469 			return ret;
1470 		}
1471 		attrs->n_actions++;
1472 		ret = 0;
1473 	}
1474 	return ret;
1475 }
1476 
1477 static int parse_assignment(struct trace_array *tr,
1478 			    char *str, struct hist_trigger_attrs *attrs)
1479 {
1480 	int len, ret = 0;
1481 
1482 	if ((len = str_has_prefix(str, "key=")) ||
1483 	    (len = str_has_prefix(str, "keys="))) {
1484 		attrs->keys_str = kstrdup(str + len, GFP_KERNEL);
1485 		if (!attrs->keys_str) {
1486 			ret = -ENOMEM;
1487 			goto out;
1488 		}
1489 	} else if ((len = str_has_prefix(str, "val=")) ||
1490 		   (len = str_has_prefix(str, "vals=")) ||
1491 		   (len = str_has_prefix(str, "values="))) {
1492 		attrs->vals_str = kstrdup(str + len, GFP_KERNEL);
1493 		if (!attrs->vals_str) {
1494 			ret = -ENOMEM;
1495 			goto out;
1496 		}
1497 	} else if ((len = str_has_prefix(str, "sort="))) {
1498 		attrs->sort_key_str = kstrdup(str + len, GFP_KERNEL);
1499 		if (!attrs->sort_key_str) {
1500 			ret = -ENOMEM;
1501 			goto out;
1502 		}
1503 	} else if (str_has_prefix(str, "name=")) {
1504 		attrs->name = kstrdup(str, GFP_KERNEL);
1505 		if (!attrs->name) {
1506 			ret = -ENOMEM;
1507 			goto out;
1508 		}
1509 	} else if ((len = str_has_prefix(str, "clock="))) {
1510 		str += len;
1511 
1512 		str = strstrip(str);
1513 		attrs->clock = kstrdup(str, GFP_KERNEL);
1514 		if (!attrs->clock) {
1515 			ret = -ENOMEM;
1516 			goto out;
1517 		}
1518 	} else if ((len = str_has_prefix(str, "size="))) {
1519 		int map_bits = parse_map_size(str + len);
1520 
1521 		if (map_bits < 0) {
1522 			ret = map_bits;
1523 			goto out;
1524 		}
1525 		attrs->map_bits = map_bits;
1526 	} else {
1527 		char *assignment;
1528 
1529 		if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
1530 			hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(str));
1531 			ret = -EINVAL;
1532 			goto out;
1533 		}
1534 
1535 		assignment = kstrdup(str, GFP_KERNEL);
1536 		if (!assignment) {
1537 			ret = -ENOMEM;
1538 			goto out;
1539 		}
1540 
1541 		attrs->assignment_str[attrs->n_assignments++] = assignment;
1542 	}
1543  out:
1544 	return ret;
1545 }
1546 
1547 static struct hist_trigger_attrs *
1548 parse_hist_trigger_attrs(struct trace_array *tr, char *trigger_str)
1549 {
1550 	struct hist_trigger_attrs *attrs;
1551 	int ret = 0;
1552 
1553 	attrs = kzalloc_obj(*attrs);
1554 	if (!attrs)
1555 		return ERR_PTR(-ENOMEM);
1556 
1557 	while (trigger_str) {
1558 		char *str = strsep(&trigger_str, ":");
1559 		char *rhs;
1560 
1561 		rhs = strchr(str, '=');
1562 		if (rhs) {
1563 			if (!strlen(++rhs)) {
1564 				ret = -EINVAL;
1565 				hist_err(tr, HIST_ERR_EMPTY_ASSIGNMENT, errpos(str));
1566 				goto free;
1567 			}
1568 			ret = parse_assignment(tr, str, attrs);
1569 			if (ret)
1570 				goto free;
1571 		} else if (strcmp(str, "nohitcount") == 0 ||
1572 			   strcmp(str, "NOHC") == 0)
1573 			attrs->no_hitcount = true;
1574 		else if (strcmp(str, "pause") == 0)
1575 			attrs->pause = true;
1576 		else if ((strcmp(str, "cont") == 0) ||
1577 			 (strcmp(str, "continue") == 0))
1578 			attrs->cont = true;
1579 		else if (strcmp(str, "clear") == 0)
1580 			attrs->clear = true;
1581 		else {
1582 			ret = parse_action(str, attrs);
1583 			if (ret)
1584 				goto free;
1585 		}
1586 	}
1587 
1588 	if (!attrs->keys_str) {
1589 		ret = -EINVAL;
1590 		goto free;
1591 	}
1592 
1593 	if (!attrs->clock) {
1594 		attrs->clock = kstrdup("global", GFP_KERNEL);
1595 		if (!attrs->clock) {
1596 			ret = -ENOMEM;
1597 			goto free;
1598 		}
1599 	}
1600 
1601 	return attrs;
1602  free:
1603 	destroy_hist_trigger_attrs(attrs);
1604 
1605 	return ERR_PTR(ret);
1606 }
1607 
1608 static inline void save_comm(char *comm, struct task_struct *task)
1609 {
1610 	if (!task->pid) {
1611 		strcpy(comm, "<idle>");
1612 		return;
1613 	}
1614 
1615 	if (WARN_ON_ONCE(task->pid < 0)) {
1616 		strcpy(comm, "<XXX>");
1617 		return;
1618 	}
1619 
1620 	strscpy(comm, task->comm, TASK_COMM_LEN);
1621 }
1622 
1623 static void hist_elt_data_free(struct hist_elt_data *elt_data)
1624 {
1625 	unsigned int i;
1626 
1627 	for (i = 0; i < elt_data->n_field_var_str; i++)
1628 		kfree(elt_data->field_var_str[i]);
1629 
1630 	kfree(elt_data->comm);
1631 	kfree(elt_data);
1632 }
1633 
1634 static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
1635 {
1636 	struct hist_elt_data *elt_data = elt->private_data;
1637 
1638 	hist_elt_data_free(elt_data);
1639 }
1640 
1641 static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
1642 {
1643 	struct hist_trigger_data *hist_data = elt->map->private_data;
1644 	unsigned int size = TASK_COMM_LEN;
1645 	struct hist_elt_data *elt_data;
1646 	struct hist_field *hist_field;
1647 	unsigned int i, n_str;
1648 
1649 	BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1));
1650 
1651 	n_str = hist_data->n_field_var_str + hist_data->n_save_var_str +
1652 		hist_data->n_var_str;
1653 	if (n_str > SYNTH_FIELDS_MAX)
1654 		return -EINVAL;
1655 
1656 	elt_data = kzalloc_flex(*elt_data, field_var_str, n_str);
1657 	if (!elt_data)
1658 		return -ENOMEM;
1659 
1660 	elt_data->n_field_var_str = n_str;
1661 
1662 	for_each_hist_field(i, hist_data) {
1663 		hist_field = hist_data->fields[i];
1664 
1665 		if (hist_field->flags & HIST_FIELD_FL_EXECNAME) {
1666 			elt_data->comm = kzalloc(size, GFP_KERNEL);
1667 			if (!elt_data->comm) {
1668 				kfree(elt_data);
1669 				return -ENOMEM;
1670 			}
1671 			break;
1672 		}
1673 	}
1674 
1675 	size = STR_VAR_LEN_MAX;
1676 
1677 	for (i = 0; i < n_str; i++) {
1678 		elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
1679 		if (!elt_data->field_var_str[i]) {
1680 			hist_elt_data_free(elt_data);
1681 			return -ENOMEM;
1682 		}
1683 	}
1684 
1685 	elt->private_data = elt_data;
1686 
1687 	return 0;
1688 }
1689 
1690 static void hist_trigger_elt_data_init(struct tracing_map_elt *elt)
1691 {
1692 	struct hist_elt_data *elt_data = elt->private_data;
1693 
1694 	if (elt_data->comm)
1695 		save_comm(elt_data->comm, current);
1696 }
1697 
1698 static const struct tracing_map_ops hist_trigger_elt_data_ops = {
1699 	.elt_alloc	= hist_trigger_elt_data_alloc,
1700 	.elt_free	= hist_trigger_elt_data_free,
1701 	.elt_init	= hist_trigger_elt_data_init,
1702 };
1703 
1704 static const char *get_hist_field_flags(struct hist_field *hist_field)
1705 {
1706 	const char *flags_str = NULL;
1707 
1708 	if (hist_field->flags & HIST_FIELD_FL_HEX)
1709 		flags_str = "hex";
1710 	else if (hist_field->flags & HIST_FIELD_FL_SYM)
1711 		flags_str = "sym";
1712 	else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
1713 		flags_str = "sym-offset";
1714 	else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
1715 		flags_str = "execname";
1716 	else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
1717 		flags_str = "syscall";
1718 	else if (hist_field->flags & HIST_FIELD_FL_LOG2)
1719 		flags_str = "log2";
1720 	else if (hist_field->flags & HIST_FIELD_FL_BUCKET)
1721 		flags_str = "buckets";
1722 	else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
1723 		flags_str = "usecs";
1724 	else if (hist_field->flags & HIST_FIELD_FL_PERCENT)
1725 		flags_str = "percent";
1726 	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
1727 		flags_str = "graph";
1728 	else if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
1729 		flags_str = "stacktrace";
1730 
1731 	return flags_str;
1732 }
1733 
1734 static bool expr_field_str(struct hist_field *field, struct seq_buf *s)
1735 {
1736 	const char *field_name;
1737 
1738 	if (field->flags & HIST_FIELD_FL_VAR_REF) {
1739 		if (!field->system)
1740 			seq_buf_putc(s, '$');
1741 	} else if (field->flags & HIST_FIELD_FL_CONST)
1742 		seq_buf_printf(s, "%llu", field->constant);
1743 
1744 	field_name = hist_field_name(field, 0);
1745 	if (!field_name)
1746 		return false;
1747 
1748 	seq_buf_puts(s, field_name);
1749 
1750 	if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) {
1751 		const char *flags_str = get_hist_field_flags(field);
1752 
1753 		if (flags_str)
1754 			seq_buf_printf(s, ".%s", flags_str);
1755 	}
1756 
1757 	return !seq_buf_has_overflowed(s);
1758 }
1759 
1760 static char *expr_str(struct hist_field *field, unsigned int level)
1761 {
1762 	char *expr __free(kfree) = NULL;
1763 	struct seq_buf s;
1764 
1765 	if (level > 1)
1766 		return ERR_PTR(-EINVAL);
1767 
1768 	expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
1769 	if (!expr)
1770 		return ERR_PTR(-ENOMEM);
1771 
1772 	seq_buf_init(&s, expr, MAX_FILTER_STR_VAL);
1773 
1774 	if (!field->operands[0]) {
1775 		if (!expr_field_str(field, &s))
1776 			return ERR_PTR(-E2BIG);
1777 
1778 		return_ptr(expr);
1779 	}
1780 
1781 	if (field->operator == FIELD_OP_UNARY_MINUS) {
1782 		char *subexpr;
1783 
1784 		subexpr = expr_str(field->operands[0], ++level);
1785 		if (IS_ERR(subexpr))
1786 			return subexpr;
1787 
1788 		seq_buf_printf(&s, "-(%s)", subexpr);
1789 		kfree(subexpr);
1790 
1791 		if (seq_buf_has_overflowed(&s))
1792 			return ERR_PTR(-E2BIG);
1793 
1794 		return_ptr(expr);
1795 	}
1796 
1797 	if (!expr_field_str(field->operands[0], &s))
1798 		return ERR_PTR(-E2BIG);
1799 
1800 	switch (field->operator) {
1801 	case FIELD_OP_MINUS:
1802 		seq_buf_putc(&s, '-');
1803 		break;
1804 	case FIELD_OP_PLUS:
1805 		seq_buf_putc(&s, '+');
1806 		break;
1807 	case FIELD_OP_DIV:
1808 		seq_buf_putc(&s, '/');
1809 		break;
1810 	case FIELD_OP_MULT:
1811 		seq_buf_putc(&s, '*');
1812 		break;
1813 	default:
1814 		return ERR_PTR(-EINVAL);
1815 	}
1816 
1817 	if (seq_buf_has_overflowed(&s) ||
1818 	    !expr_field_str(field->operands[1], &s))
1819 		return ERR_PTR(-E2BIG);
1820 
1821 	return_ptr(expr);
1822 }
1823 
1824 /*
1825  * If field_op != FIELD_OP_NONE, *sep points to the root operator
1826  * of the expression tree to be evaluated.
1827  */
1828 static int contains_operator(char *str, char **sep)
1829 {
1830 	enum field_op_id field_op = FIELD_OP_NONE;
1831 	char *minus_op, *plus_op, *div_op, *mult_op;
1832 
1833 
1834 	/*
1835 	 * Report the last occurrence of the operators first, so that the
1836 	 * expression is evaluated left to right. This is important since
1837 	 * subtraction and division are not associative.
1838 	 *
1839 	 *	e.g
1840 	 *		64/8/4/2 is 1, i.e 64/8/4/2 = ((64/8)/4)/2
1841 	 *		14-7-5-2 is 0, i.e 14-7-5-2 = ((14-7)-5)-2
1842 	 */
1843 
1844 	/*
1845 	 * First, find lower precedence addition and subtraction
1846 	 * since the expression will be evaluated recursively.
1847 	 */
1848 	minus_op = strrchr(str, '-');
1849 	if (minus_op) {
1850 		/*
1851 		 * Unary minus is not supported in sub-expressions. If
1852 		 * present, it is always the next root operator.
1853 		 */
1854 		if (minus_op == str) {
1855 			field_op = FIELD_OP_UNARY_MINUS;
1856 			goto out;
1857 		}
1858 
1859 		field_op = FIELD_OP_MINUS;
1860 	}
1861 
1862 	plus_op = strrchr(str, '+');
1863 	if (plus_op || minus_op) {
1864 		/*
1865 		 * For operators of the same precedence use to rightmost as the
1866 		 * root, so that the expression is evaluated left to right.
1867 		 */
1868 		if (plus_op > minus_op)
1869 			field_op = FIELD_OP_PLUS;
1870 		goto out;
1871 	}
1872 
1873 	/*
1874 	 * Multiplication and division have higher precedence than addition and
1875 	 * subtraction.
1876 	 */
1877 	div_op = strrchr(str, '/');
1878 	if (div_op)
1879 		field_op = FIELD_OP_DIV;
1880 
1881 	mult_op = strrchr(str, '*');
1882 	/*
1883 	 * For operators of the same precedence use to rightmost as the
1884 	 * root, so that the expression is evaluated left to right.
1885 	 */
1886 	if (mult_op > div_op)
1887 		field_op = FIELD_OP_MULT;
1888 
1889 out:
1890 	if (sep) {
1891 		switch (field_op) {
1892 		case FIELD_OP_UNARY_MINUS:
1893 		case FIELD_OP_MINUS:
1894 			*sep = minus_op;
1895 			break;
1896 		case FIELD_OP_PLUS:
1897 			*sep = plus_op;
1898 			break;
1899 		case FIELD_OP_DIV:
1900 			*sep = div_op;
1901 			break;
1902 		case FIELD_OP_MULT:
1903 			*sep = mult_op;
1904 			break;
1905 		case FIELD_OP_NONE:
1906 		default:
1907 			*sep = NULL;
1908 			break;
1909 		}
1910 	}
1911 
1912 	return field_op;
1913 }
1914 
1915 static void __destroy_hist_field(struct hist_field *hist_field)
1916 {
1917 	kfree(hist_field->var.name);
1918 	kfree(hist_field->name);
1919 
1920 	/* Can likely be a const */
1921 	kfree_const(hist_field->type);
1922 
1923 	kfree(hist_field->system);
1924 	kfree(hist_field->event_name);
1925 
1926 	kfree(hist_field);
1927 }
1928 
1929 static void destroy_hist_field(struct hist_field *hist_field,
1930 			       unsigned int level)
1931 {
1932 	unsigned int i;
1933 
1934 	if (level > 3)
1935 		return;
1936 
1937 	if (!hist_field)
1938 		return;
1939 
1940 	if (hist_field->flags & HIST_FIELD_FL_VAR_REF)
1941 		return; /* var refs will be destroyed separately */
1942 
1943 	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
1944 		destroy_hist_field(hist_field->operands[i], level + 1);
1945 
1946 	__destroy_hist_field(hist_field);
1947 }
1948 
1949 static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
1950 					    struct ftrace_event_field *field,
1951 					    unsigned long flags,
1952 					    char *var_name)
1953 {
1954 	struct hist_field *hist_field;
1955 
1956 	if (field && is_function_field(field))
1957 		return NULL;
1958 
1959 	hist_field = kzalloc_obj(struct hist_field);
1960 	if (!hist_field)
1961 		return NULL;
1962 
1963 	hist_field->hist_data = hist_data;
1964 
1965 	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
1966 		goto out; /* caller will populate */
1967 
1968 	if (flags & HIST_FIELD_FL_VAR_REF) {
1969 		hist_field->fn_num = HIST_FIELD_FN_VAR_REF;
1970 		goto out;
1971 	}
1972 
1973 	if (flags & HIST_FIELD_FL_HITCOUNT) {
1974 		hist_field->fn_num = HIST_FIELD_FN_COUNTER;
1975 		hist_field->size = sizeof(u64);
1976 		hist_field->type = "u64";
1977 		goto out;
1978 	}
1979 
1980 	if (flags & HIST_FIELD_FL_CONST) {
1981 		hist_field->fn_num = HIST_FIELD_FN_CONST;
1982 		hist_field->size = sizeof(u64);
1983 		hist_field->type = "u64";
1984 		goto out;
1985 	}
1986 
1987 	if (flags & HIST_FIELD_FL_STACKTRACE) {
1988 		if (field)
1989 			hist_field->fn_num = HIST_FIELD_FN_STACK;
1990 		else
1991 			hist_field->fn_num = HIST_FIELD_FN_NOP;
1992 		hist_field->size = HIST_STACKTRACE_SIZE;
1993 		hist_field->type = kstrdup_const("unsigned long[]", GFP_KERNEL);
1994 		if (!hist_field->type)
1995 			goto free;
1996 		goto out;
1997 	}
1998 
1999 	if (flags & (HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET)) {
2000 		unsigned long fl = flags & ~(HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET);
2001 		hist_field->fn_num = flags & HIST_FIELD_FL_LOG2 ? HIST_FIELD_FN_LOG2 :
2002 			HIST_FIELD_FN_BUCKET;
2003 		hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
2004 		if (!hist_field->operands[0])
2005 			goto free;
2006 		hist_field->size = hist_field->operands[0]->size;
2007 		hist_field->type = kstrdup_const(hist_field->operands[0]->type, GFP_KERNEL);
2008 		if (!hist_field->type)
2009 			goto free;
2010 		goto out;
2011 	}
2012 
2013 	if (flags & HIST_FIELD_FL_TIMESTAMP) {
2014 		hist_field->fn_num = HIST_FIELD_FN_TIMESTAMP;
2015 		hist_field->size = sizeof(u64);
2016 		hist_field->type = "u64";
2017 		goto out;
2018 	}
2019 
2020 	if (flags & HIST_FIELD_FL_CPU) {
2021 		hist_field->fn_num = HIST_FIELD_FN_CPU;
2022 		hist_field->size = sizeof(int);
2023 		hist_field->type = "unsigned int";
2024 		goto out;
2025 	}
2026 
2027 	if (flags & HIST_FIELD_FL_COMM) {
2028 		hist_field->fn_num = HIST_FIELD_FN_COMM;
2029 		hist_field->size = MAX_FILTER_STR_VAL;
2030 		hist_field->type = "char[]";
2031 		goto out;
2032 	}
2033 
2034 	if (WARN_ON_ONCE(!field))
2035 		goto out;
2036 
2037 	/* Pointers to strings are just pointers and dangerous to dereference */
2038 	if (is_string_field(field) &&
2039 	    (field->filter_type != FILTER_PTR_STRING)) {
2040 		flags |= HIST_FIELD_FL_STRING;
2041 
2042 		hist_field->size = MAX_FILTER_STR_VAL;
2043 		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
2044 		if (!hist_field->type)
2045 			goto free;
2046 
2047 		if (field->filter_type == FILTER_STATIC_STRING) {
2048 			hist_field->fn_num = HIST_FIELD_FN_STRING;
2049 			hist_field->size = field->size;
2050 		} else if (field->filter_type == FILTER_DYN_STRING) {
2051 			hist_field->fn_num = HIST_FIELD_FN_DYNSTRING;
2052 		} else if (field->filter_type == FILTER_RDYN_STRING)
2053 			hist_field->fn_num = HIST_FIELD_FN_RELDYNSTRING;
2054 		else
2055 			hist_field->fn_num = HIST_FIELD_FN_PSTRING;
2056 	} else if (field->filter_type == FILTER_STACKTRACE) {
2057 		flags |= HIST_FIELD_FL_STACKTRACE;
2058 
2059 		hist_field->size = MAX_FILTER_STR_VAL;
2060 		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
2061 		if (!hist_field->type)
2062 			goto free;
2063 
2064 		hist_field->fn_num = HIST_FIELD_FN_STACK;
2065 	} else {
2066 		hist_field->size = field->size;
2067 		hist_field->is_signed = field->is_signed;
2068 		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
2069 		if (!hist_field->type)
2070 			goto free;
2071 
2072 		hist_field->fn_num = select_value_fn(field->size,
2073 						     field->is_signed);
2074 		if (hist_field->fn_num == HIST_FIELD_FN_NOP) {
2075 			destroy_hist_field(hist_field, 0);
2076 			return NULL;
2077 		}
2078 	}
2079  out:
2080 	hist_field->field = field;
2081 	hist_field->flags = flags;
2082 
2083 	if (var_name) {
2084 		hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
2085 		if (!hist_field->var.name)
2086 			goto free;
2087 	}
2088 
2089 	return hist_field;
2090  free:
2091 	destroy_hist_field(hist_field, 0);
2092 	return NULL;
2093 }
2094 
2095 static void destroy_hist_fields(struct hist_trigger_data *hist_data)
2096 {
2097 	unsigned int i;
2098 
2099 	for (i = 0; i < HIST_FIELDS_MAX; i++) {
2100 		if (hist_data->fields[i]) {
2101 			destroy_hist_field(hist_data->fields[i], 0);
2102 			hist_data->fields[i] = NULL;
2103 		}
2104 	}
2105 
2106 	for (i = 0; i < hist_data->n_var_refs; i++) {
2107 		WARN_ON(!(hist_data->var_refs[i]->flags & HIST_FIELD_FL_VAR_REF));
2108 		__destroy_hist_field(hist_data->var_refs[i]);
2109 		hist_data->var_refs[i] = NULL;
2110 	}
2111 }
2112 
2113 static int init_var_ref(struct hist_field *ref_field,
2114 			struct hist_field *var_field,
2115 			char *system, char *event_name)
2116 {
2117 	int err = 0;
2118 
2119 	ref_field->var.idx = var_field->var.idx;
2120 	ref_field->var.hist_data = var_field->hist_data;
2121 	ref_field->size = var_field->size;
2122 	ref_field->is_signed = var_field->is_signed;
2123 	ref_field->flags |= var_field->flags &
2124 		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2125 
2126 	if (system) {
2127 		ref_field->system = kstrdup(system, GFP_KERNEL);
2128 		if (!ref_field->system)
2129 			return -ENOMEM;
2130 	}
2131 
2132 	if (event_name) {
2133 		ref_field->event_name = kstrdup(event_name, GFP_KERNEL);
2134 		if (!ref_field->event_name) {
2135 			err = -ENOMEM;
2136 			goto free;
2137 		}
2138 	}
2139 
2140 	if (var_field->var.name) {
2141 		ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
2142 		if (!ref_field->name) {
2143 			err = -ENOMEM;
2144 			goto free;
2145 		}
2146 	} else if (var_field->name) {
2147 		ref_field->name = kstrdup(var_field->name, GFP_KERNEL);
2148 		if (!ref_field->name) {
2149 			err = -ENOMEM;
2150 			goto free;
2151 		}
2152 	}
2153 
2154 	ref_field->type = kstrdup_const(var_field->type, GFP_KERNEL);
2155 	if (!ref_field->type) {
2156 		err = -ENOMEM;
2157 		goto free;
2158 	}
2159  out:
2160 	return err;
2161  free:
2162 	kfree(ref_field->system);
2163 	ref_field->system = NULL;
2164 	kfree(ref_field->event_name);
2165 	ref_field->event_name = NULL;
2166 	kfree(ref_field->name);
2167 	ref_field->name = NULL;
2168 
2169 	goto out;
2170 }
2171 
2172 static int find_var_ref_idx(struct hist_trigger_data *hist_data,
2173 			    struct hist_field *var_field)
2174 {
2175 	struct hist_field *ref_field;
2176 	int i;
2177 
2178 	for (i = 0; i < hist_data->n_var_refs; i++) {
2179 		ref_field = hist_data->var_refs[i];
2180 		if (ref_field->var.idx == var_field->var.idx &&
2181 		    ref_field->var.hist_data == var_field->hist_data)
2182 			return i;
2183 	}
2184 
2185 	return -ENOENT;
2186 }
2187 
2188 /**
2189  * create_var_ref - Create a variable reference and attach it to trigger
2190  * @hist_data: The trigger that will be referencing the variable
2191  * @var_field: The VAR field to create a reference to
2192  * @system: The optional system string
2193  * @event_name: The optional event_name string
2194  *
2195  * Given a variable hist_field, create a VAR_REF hist_field that
2196  * represents a reference to it.
2197  *
2198  * This function also adds the reference to the trigger that
2199  * now references the variable.
2200  *
2201  * Return: The VAR_REF field if successful, NULL if not
2202  */
2203 static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
2204 					 struct hist_field *var_field,
2205 					 char *system, char *event_name)
2206 {
2207 	unsigned long flags = HIST_FIELD_FL_VAR_REF;
2208 	struct hist_field *ref_field;
2209 	int i;
2210 
2211 	/* Check if the variable already exists */
2212 	for (i = 0; i < hist_data->n_var_refs; i++) {
2213 		ref_field = hist_data->var_refs[i];
2214 		if (ref_field->var.idx == var_field->var.idx &&
2215 		    ref_field->var.hist_data == var_field->hist_data)
2216 			return ref_field;
2217 	}
2218 	/* Sanity check to avoid out-of-bound write on 'hist_data->var_refs' */
2219 	if (hist_data->n_var_refs >= TRACING_MAP_VARS_MAX)
2220 		return NULL;
2221 	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
2222 	if (ref_field) {
2223 		if (init_var_ref(ref_field, var_field, system, event_name)) {
2224 			__destroy_hist_field(ref_field);
2225 			return NULL;
2226 		}
2227 
2228 		hist_data->var_refs[hist_data->n_var_refs] = ref_field;
2229 		ref_field->var_ref_idx = hist_data->n_var_refs++;
2230 	}
2231 
2232 	return ref_field;
2233 }
2234 
2235 static bool is_var_ref(char *var_name)
2236 {
2237 	if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
2238 		return false;
2239 
2240 	return true;
2241 }
2242 
2243 static char *field_name_from_var(struct hist_trigger_data *hist_data,
2244 				 char *var_name)
2245 {
2246 	char *name, *field;
2247 	unsigned int i;
2248 
2249 	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
2250 		name = hist_data->attrs->var_defs.name[i];
2251 
2252 		if (strcmp(var_name, name) == 0) {
2253 			field = hist_data->attrs->var_defs.expr[i];
2254 			if (contains_operator(field, NULL) || is_var_ref(field))
2255 				continue;
2256 			return field;
2257 		}
2258 	}
2259 
2260 	return NULL;
2261 }
2262 
2263 static char *local_field_var_ref(struct hist_trigger_data *hist_data,
2264 				 char *system, char *event_name,
2265 				 char *var_name)
2266 {
2267 	struct trace_event_call *call;
2268 
2269 	if (system && event_name) {
2270 		call = hist_data->event_file->event_call;
2271 
2272 		if (strcmp(system, call->class->system) != 0)
2273 			return NULL;
2274 
2275 		if (strcmp(event_name, trace_event_name(call)) != 0)
2276 			return NULL;
2277 	}
2278 
2279 	if (!!system != !!event_name)
2280 		return NULL;
2281 
2282 	if (!is_var_ref(var_name))
2283 		return NULL;
2284 
2285 	var_name++;
2286 
2287 	return field_name_from_var(hist_data, var_name);
2288 }
2289 
2290 static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
2291 					char *system, char *event_name,
2292 					char *var_name)
2293 {
2294 	struct hist_field *var_field = NULL, *ref_field = NULL;
2295 	struct trace_array *tr = hist_data->event_file->tr;
2296 
2297 	if (!is_var_ref(var_name))
2298 		return NULL;
2299 
2300 	var_name++;
2301 
2302 	var_field = find_event_var(hist_data, system, event_name, var_name);
2303 	if (var_field)
2304 		ref_field = create_var_ref(hist_data, var_field,
2305 					   system, event_name);
2306 
2307 	if (!ref_field)
2308 		hist_err(tr, HIST_ERR_VAR_NOT_FOUND, errpos(var_name));
2309 
2310 	return ref_field;
2311 }
2312 
2313 static struct ftrace_event_field *
2314 parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
2315 	    char *field_str, unsigned long *flags, unsigned long *buckets)
2316 {
2317 	struct ftrace_event_field *field = NULL;
2318 	char *field_name, *modifier, *str;
2319 	struct trace_array *tr = file->tr;
2320 	bool stack_modifier = false;
2321 
2322 	modifier = str = kstrdup(field_str, GFP_KERNEL);
2323 	if (!modifier)
2324 		return ERR_PTR(-ENOMEM);
2325 
2326 	field_name = strsep(&modifier, ".");
2327 	if (modifier) {
2328 		if (strcmp(modifier, "hex") == 0)
2329 			*flags |= HIST_FIELD_FL_HEX;
2330 		else if (strcmp(modifier, "sym") == 0)
2331 			*flags |= HIST_FIELD_FL_SYM;
2332 		/*
2333 		 * 'sym-offset' occurrences in the trigger string are modified
2334 		 * to 'symXoffset' to simplify arithmetic expression parsing.
2335 		 */
2336 		else if (strcmp(modifier, "symXoffset") == 0)
2337 			*flags |= HIST_FIELD_FL_SYM_OFFSET;
2338 		else if ((strcmp(modifier, "execname") == 0) &&
2339 			 (strcmp(field_name, "common_pid") == 0))
2340 			*flags |= HIST_FIELD_FL_EXECNAME;
2341 		else if (strcmp(modifier, "syscall") == 0)
2342 			*flags |= HIST_FIELD_FL_SYSCALL;
2343 		else if (strcmp(modifier, "stacktrace") == 0) {
2344 			*flags |= HIST_FIELD_FL_STACKTRACE;
2345 			stack_modifier = true;
2346 		} else if (strcmp(modifier, "log2") == 0)
2347 			*flags |= HIST_FIELD_FL_LOG2;
2348 		else if (strcmp(modifier, "usecs") == 0)
2349 			*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
2350 		else if (strncmp(modifier, "bucket", 6) == 0) {
2351 			int ret;
2352 
2353 			modifier += 6;
2354 
2355 			if (*modifier == 's')
2356 				modifier++;
2357 			if (*modifier != '=')
2358 				goto error;
2359 			modifier++;
2360 			ret = kstrtoul(modifier, 0, buckets);
2361 			if (ret || !(*buckets))
2362 				goto error;
2363 			*flags |= HIST_FIELD_FL_BUCKET;
2364 		} else if (strncmp(modifier, "percent", 7) == 0) {
2365 			if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
2366 				goto error;
2367 			*flags |= HIST_FIELD_FL_PERCENT;
2368 		} else if (strncmp(modifier, "graph", 5) == 0) {
2369 			if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
2370 				goto error;
2371 			*flags |= HIST_FIELD_FL_GRAPH;
2372 		} else {
2373  error:
2374 			hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
2375 			field = ERR_PTR(-EINVAL);
2376 			goto out;
2377 		}
2378 	}
2379 
2380 	if (strcmp(field_name, "common_timestamp") == 0) {
2381 		*flags |= HIST_FIELD_FL_TIMESTAMP;
2382 		hist_data->enable_timestamps = true;
2383 		if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
2384 			hist_data->attrs->ts_in_usecs = true;
2385 	} else if (strcmp(field_name, "common_stacktrace") == 0) {
2386 		*flags |= HIST_FIELD_FL_STACKTRACE;
2387 	} else if (strcmp(field_name, "common_cpu") == 0) {
2388 		*flags |= HIST_FIELD_FL_CPU;
2389 	} else if (strcmp(field_name, "common_comm") == 0) {
2390 		*flags |= HIST_FIELD_FL_COMM | HIST_FIELD_FL_STRING;
2391 	} else if (strcmp(field_name, "hitcount") == 0)
2392 		*flags |= HIST_FIELD_FL_HITCOUNT;
2393 	else {
2394 		field = trace_find_event_field(file->event_call, field_name);
2395 		if (!field || !field->size) {
2396 			/*
2397 			 * For backward compatibility, if field_name
2398 			 * was "cpu" or "stacktrace", then we treat this
2399 			 * the same as common_cpu and common_stacktrace
2400 			 * respectively. This also works for "CPU", and
2401 			 * "STACKTRACE".
2402 			 */
2403 			if (field && field->filter_type == FILTER_CPU) {
2404 				*flags |= HIST_FIELD_FL_CPU;
2405 			} else if (field && field->filter_type == FILTER_STACKTRACE) {
2406 				*flags |= HIST_FIELD_FL_STACKTRACE;
2407 				field = NULL;
2408 			} else if (field && field->filter_type == FILTER_COMM) {
2409 				*flags |= HIST_FIELD_FL_COMM | HIST_FIELD_FL_STRING;
2410 			} else {
2411 				hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,
2412 					 errpos(field_name));
2413 				field = ERR_PTR(-EINVAL);
2414 				goto out;
2415 			}
2416 		}
2417 	}
2418 
2419 	if (stack_modifier &&
2420 	    (!field || field->filter_type != FILTER_STACKTRACE)) {
2421 		hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
2422 		field = ERR_PTR(-EINVAL);
2423 	}
2424  out:
2425 	kfree(str);
2426 
2427 	return field;
2428 }
2429 
2430 static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
2431 				       struct hist_field *var_ref,
2432 				       char *var_name)
2433 {
2434 	struct hist_field *alias = NULL;
2435 	unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;
2436 
2437 	alias = create_hist_field(hist_data, NULL, flags, var_name);
2438 	if (!alias)
2439 		return NULL;
2440 
2441 	alias->fn_num = var_ref->fn_num;
2442 	alias->operands[0] = var_ref;
2443 
2444 	if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
2445 		destroy_hist_field(alias, 0);
2446 		return NULL;
2447 	}
2448 
2449 	alias->var_ref_idx = var_ref->var_ref_idx;
2450 
2451 	return alias;
2452 }
2453 
2454 static struct hist_field *parse_const(struct hist_trigger_data *hist_data,
2455 				      char *str, char *var_name,
2456 				      unsigned long *flags)
2457 {
2458 	struct trace_array *tr = hist_data->event_file->tr;
2459 	struct hist_field *field = NULL;
2460 	u64 constant;
2461 
2462 	if (kstrtoull(str, 0, &constant)) {
2463 		hist_err(tr, HIST_ERR_EXPECT_NUMBER, errpos(str));
2464 		return NULL;
2465 	}
2466 
2467 	*flags |= HIST_FIELD_FL_CONST;
2468 	field = create_hist_field(hist_data, NULL, *flags, var_name);
2469 	if (!field)
2470 		return NULL;
2471 
2472 	field->constant = constant;
2473 
2474 	return field;
2475 }
2476 
2477 static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
2478 				     struct trace_event_file *file, char *str,
2479 				     unsigned long *flags, char *var_name)
2480 {
2481 	char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
2482 	struct ftrace_event_field *field = NULL;
2483 	struct hist_field *hist_field = NULL;
2484 	unsigned long buckets = 0;
2485 	int ret = 0;
2486 
2487 	if (isdigit(str[0])) {
2488 		hist_field = parse_const(hist_data, str, var_name, flags);
2489 		if (!hist_field) {
2490 			ret = -EINVAL;
2491 			goto out;
2492 		}
2493 		return hist_field;
2494 	}
2495 
2496 	s = strchr(str, '.');
2497 	if (s) {
2498 		s = strchr(++s, '.');
2499 		if (s) {
2500 			ref_system = strsep(&str, ".");
2501 			if (!str) {
2502 				ret = -EINVAL;
2503 				goto out;
2504 			}
2505 			ref_event = strsep(&str, ".");
2506 			if (!str) {
2507 				ret = -EINVAL;
2508 				goto out;
2509 			}
2510 			ref_var = str;
2511 		}
2512 	}
2513 
2514 	s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
2515 	if (!s) {
2516 		hist_field = parse_var_ref(hist_data, ref_system,
2517 					   ref_event, ref_var);
2518 		if (hist_field) {
2519 			if (var_name) {
2520 				hist_field = create_alias(hist_data, hist_field, var_name);
2521 				if (!hist_field) {
2522 					ret = -ENOMEM;
2523 					goto out;
2524 				}
2525 			}
2526 			return hist_field;
2527 		}
2528 	} else
2529 		str = s;
2530 
2531 	field = parse_field(hist_data, file, str, flags, &buckets);
2532 	if (IS_ERR(field)) {
2533 		ret = PTR_ERR(field);
2534 		goto out;
2535 	}
2536 
2537 	hist_field = create_hist_field(hist_data, field, *flags, var_name);
2538 	if (!hist_field) {
2539 		ret = -ENOMEM;
2540 		goto out;
2541 	}
2542 	hist_field->buckets = buckets;
2543 
2544 	return hist_field;
2545  out:
2546 	return ERR_PTR(ret);
2547 }
2548 
2549 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2550 				     struct trace_event_file *file,
2551 				     char *str, unsigned long flags,
2552 				     char *var_name, unsigned int *n_subexprs);
2553 
2554 static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
2555 				      struct trace_event_file *file,
2556 				      char *str, unsigned long flags,
2557 				      char *var_name, unsigned int *n_subexprs)
2558 {
2559 	struct hist_field *operand1, *expr = NULL;
2560 	unsigned long operand_flags;
2561 	int ret = 0;
2562 	char *s;
2563 
2564 	/* Unary minus operator, increment n_subexprs */
2565 	++*n_subexprs;
2566 
2567 	/* we support only -(xxx) i.e. explicit parens required */
2568 
2569 	if (*n_subexprs > 3) {
2570 		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2571 		ret = -EINVAL;
2572 		goto free;
2573 	}
2574 
2575 	str++; /* skip leading '-' */
2576 
2577 	s = strchr(str, '(');
2578 	if (s)
2579 		str++;
2580 	else {
2581 		ret = -EINVAL;
2582 		goto free;
2583 	}
2584 
2585 	s = strrchr(str, ')');
2586 	if (s) {
2587 		 /* unary minus not supported in sub-expressions */
2588 		if (*(s+1) != '\0') {
2589 			hist_err(file->tr, HIST_ERR_UNARY_MINUS_SUBEXPR,
2590 				 errpos(str));
2591 			ret = -EINVAL;
2592 			goto free;
2593 		}
2594 		*s = '\0';
2595 	}
2596 	else {
2597 		ret = -EINVAL; /* no closing ')' */
2598 		goto free;
2599 	}
2600 
2601 	flags |= HIST_FIELD_FL_EXPR;
2602 	expr = create_hist_field(hist_data, NULL, flags, var_name);
2603 	if (!expr) {
2604 		ret = -ENOMEM;
2605 		goto free;
2606 	}
2607 
2608 	operand_flags = 0;
2609 	operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2610 	if (IS_ERR(operand1)) {
2611 		ret = PTR_ERR(operand1);
2612 		goto free;
2613 	}
2614 	if (operand1->flags & HIST_FIELD_FL_STRING) {
2615 		/* String type can not be the operand of unary operator. */
2616 		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2617 		destroy_hist_field(operand1, 0);
2618 		ret = -EINVAL;
2619 		goto free;
2620 	}
2621 
2622 	expr->flags |= operand1->flags &
2623 		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2624 	expr->fn_num = HIST_FIELD_FN_UMINUS;
2625 	expr->operands[0] = operand1;
2626 	expr->size = operand1->size;
2627 	expr->is_signed = operand1->is_signed;
2628 	expr->operator = FIELD_OP_UNARY_MINUS;
2629 	expr->name = expr_str(expr, 0);
2630 	if (IS_ERR(expr->name)) {
2631 		ret = PTR_ERR(expr->name);
2632 		expr->name = NULL;
2633 		goto free;
2634 	}
2635 	expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2636 	if (!expr->type) {
2637 		ret = -ENOMEM;
2638 		goto free;
2639 	}
2640 
2641 	return expr;
2642  free:
2643 	destroy_hist_field(expr, 0);
2644 	return ERR_PTR(ret);
2645 }
2646 
2647 /*
2648  * If the operands are var refs, return pointers the
2649  * variable(s) referenced in var1 and var2, else NULL.
2650  */
2651 static int check_expr_operands(struct trace_array *tr,
2652 			       struct hist_field *operand1,
2653 			       struct hist_field *operand2,
2654 			       struct hist_field **var1,
2655 			       struct hist_field **var2)
2656 {
2657 	unsigned long operand1_flags = operand1->flags;
2658 	unsigned long operand2_flags = operand2->flags;
2659 
2660 	if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
2661 	    (operand1_flags & HIST_FIELD_FL_ALIAS)) {
2662 		struct hist_field *var;
2663 
2664 		var = find_var_field(operand1->var.hist_data, operand1->name);
2665 		if (!var)
2666 			return -EINVAL;
2667 		operand1_flags = var->flags;
2668 		*var1 = var;
2669 	}
2670 
2671 	if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
2672 	    (operand2_flags & HIST_FIELD_FL_ALIAS)) {
2673 		struct hist_field *var;
2674 
2675 		var = find_var_field(operand2->var.hist_data, operand2->name);
2676 		if (!var)
2677 			return -EINVAL;
2678 		operand2_flags = var->flags;
2679 		*var2 = var;
2680 	}
2681 
2682 	if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
2683 	    (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
2684 		hist_err(tr, HIST_ERR_TIMESTAMP_MISMATCH, 0);
2685 		return -EINVAL;
2686 	}
2687 
2688 	return 0;
2689 }
2690 
2691 static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
2692 				     struct trace_event_file *file,
2693 				     char *str, unsigned long flags,
2694 				     char *var_name, unsigned int *n_subexprs)
2695 {
2696 	struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
2697 	struct hist_field *var1 = NULL, *var2 = NULL;
2698 	unsigned long operand_flags, operand2_flags;
2699 	int field_op, ret = -EINVAL;
2700 	char *sep, *operand1_str;
2701 	enum hist_field_fn op_fn;
2702 	bool combine_consts;
2703 
2704 	if (*n_subexprs > 3) {
2705 		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
2706 		return ERR_PTR(-EINVAL);
2707 	}
2708 
2709 	field_op = contains_operator(str, &sep);
2710 
2711 	if (field_op == FIELD_OP_NONE)
2712 		return parse_atom(hist_data, file, str, &flags, var_name);
2713 
2714 	if (field_op == FIELD_OP_UNARY_MINUS)
2715 		return parse_unary(hist_data, file, str, flags, var_name, n_subexprs);
2716 
2717 	/* Binary operator found, increment n_subexprs */
2718 	++*n_subexprs;
2719 
2720 	/* Split the expression string at the root operator */
2721 	if (!sep)
2722 		return ERR_PTR(-EINVAL);
2723 
2724 	*sep = '\0';
2725 	operand1_str = str;
2726 	str = sep+1;
2727 
2728 	/* Binary operator requires both operands */
2729 	if (*operand1_str == '\0' || *str == '\0')
2730 		return ERR_PTR(-EINVAL);
2731 
2732 	operand_flags = 0;
2733 
2734 	/* LHS of string is an expression e.g. a+b in a+b+c */
2735 	operand1 = parse_expr(hist_data, file, operand1_str, operand_flags, NULL, n_subexprs);
2736 	if (IS_ERR(operand1))
2737 		return ERR_CAST(operand1);
2738 
2739 	if (operand1->flags & HIST_FIELD_FL_STRING) {
2740 		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(operand1_str));
2741 		ret = -EINVAL;
2742 		goto free_op1;
2743 	}
2744 
2745 	/* RHS of string is another expression e.g. c in a+b+c */
2746 	operand_flags = 0;
2747 	operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
2748 	if (IS_ERR(operand2)) {
2749 		ret = PTR_ERR(operand2);
2750 		goto free_op1;
2751 	}
2752 	if (operand2->flags & HIST_FIELD_FL_STRING) {
2753 		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
2754 		ret = -EINVAL;
2755 		goto free_operands;
2756 	}
2757 
2758 	switch (field_op) {
2759 	case FIELD_OP_MINUS:
2760 		op_fn = HIST_FIELD_FN_MINUS;
2761 		break;
2762 	case FIELD_OP_PLUS:
2763 		op_fn = HIST_FIELD_FN_PLUS;
2764 		break;
2765 	case FIELD_OP_DIV:
2766 		op_fn = HIST_FIELD_FN_DIV;
2767 		break;
2768 	case FIELD_OP_MULT:
2769 		op_fn = HIST_FIELD_FN_MULT;
2770 		break;
2771 	default:
2772 		ret = -EINVAL;
2773 		goto free_operands;
2774 	}
2775 
2776 	ret = check_expr_operands(file->tr, operand1, operand2, &var1, &var2);
2777 	if (ret)
2778 		goto free_operands;
2779 
2780 	operand_flags = var1 ? var1->flags : operand1->flags;
2781 	operand2_flags = var2 ? var2->flags : operand2->flags;
2782 
2783 	/*
2784 	 * If both operands are constant, the expression can be
2785 	 * collapsed to a single constant.
2786 	 */
2787 	combine_consts = operand_flags & operand2_flags & HIST_FIELD_FL_CONST;
2788 
2789 	flags |= combine_consts ? HIST_FIELD_FL_CONST : HIST_FIELD_FL_EXPR;
2790 
2791 	flags |= operand1->flags &
2792 		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
2793 
2794 	expr = create_hist_field(hist_data, NULL, flags, var_name);
2795 	if (!expr) {
2796 		ret = -ENOMEM;
2797 		goto free_operands;
2798 	}
2799 
2800 	operand1->read_once = true;
2801 	operand2->read_once = true;
2802 
2803 	/* The operands are now owned and free'd by 'expr' */
2804 	expr->operands[0] = operand1;
2805 	expr->operands[1] = operand2;
2806 
2807 	if (field_op == FIELD_OP_DIV &&
2808 			operand2_flags & HIST_FIELD_FL_CONST) {
2809 		u64 divisor = var2 ? var2->constant : operand2->constant;
2810 
2811 		if (!divisor) {
2812 			hist_err(file->tr, HIST_ERR_DIVISION_BY_ZERO, errpos(str));
2813 			ret = -EDOM;
2814 			goto free_expr;
2815 		}
2816 
2817 		/*
2818 		 * Copy the divisor here so we don't have to look it up
2819 		 * later if this is a var ref
2820 		 */
2821 		operand2->constant = divisor;
2822 		op_fn = hist_field_get_div_fn(operand2);
2823 	}
2824 
2825 	expr->fn_num = op_fn;
2826 
2827 	if (combine_consts) {
2828 		if (var1)
2829 			expr->operands[0] = var1;
2830 		if (var2)
2831 			expr->operands[1] = var2;
2832 
2833 		expr->constant = hist_fn_call(expr, NULL, NULL, NULL, NULL);
2834 		expr->fn_num = HIST_FIELD_FN_CONST;
2835 
2836 		expr->operands[0] = NULL;
2837 		expr->operands[1] = NULL;
2838 
2839 		/*
2840 		 * var refs won't be destroyed immediately
2841 		 * See: destroy_hist_field()
2842 		 */
2843 		destroy_hist_field(operand2, 0);
2844 		destroy_hist_field(operand1, 0);
2845 
2846 		expr->name = expr_str(expr, 0);
2847 		if (IS_ERR(expr->name)) {
2848 			ret = PTR_ERR(expr->name);
2849 			expr->name = NULL;
2850 			goto free_expr;
2851 		}
2852 	} else {
2853 		/* The operand sizes should be the same, so just pick one */
2854 		expr->size = operand1->size;
2855 		expr->is_signed = operand1->is_signed;
2856 
2857 		expr->operator = field_op;
2858 		expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
2859 		if (!expr->type) {
2860 			ret = -ENOMEM;
2861 			goto free_expr;
2862 		}
2863 
2864 		expr->name = expr_str(expr, 0);
2865 		if (IS_ERR(expr->name)) {
2866 			ret = PTR_ERR(expr->name);
2867 			expr->name = NULL;
2868 			goto free_expr;
2869 		}
2870 	}
2871 
2872 	return expr;
2873 
2874 free_operands:
2875 	destroy_hist_field(operand2, 0);
2876 free_op1:
2877 	destroy_hist_field(operand1, 0);
2878 	return ERR_PTR(ret);
2879 
2880 free_expr:
2881 	destroy_hist_field(expr, 0);
2882 	return ERR_PTR(ret);
2883 }
2884 
2885 static char *find_trigger_filter(struct hist_trigger_data *hist_data,
2886 				 struct trace_event_file *file)
2887 {
2888 	struct event_trigger_data *test;
2889 
2890 	lockdep_assert_held(&event_mutex);
2891 
2892 	list_for_each_entry(test, &file->triggers, list) {
2893 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2894 			if (test->private_data == hist_data)
2895 				return test->filter_str;
2896 		}
2897 	}
2898 
2899 	return NULL;
2900 }
2901 
2902 static struct event_command trigger_hist_cmd;
2903 static int event_hist_trigger_parse(struct event_command *cmd_ops,
2904 				    struct trace_event_file *file,
2905 				    char *glob, char *cmd,
2906 				    char *param_and_filter);
2907 
2908 static bool compatible_keys(struct hist_trigger_data *target_hist_data,
2909 			    struct hist_trigger_data *hist_data,
2910 			    unsigned int n_keys)
2911 {
2912 	struct hist_field *target_hist_field, *hist_field;
2913 	unsigned int n, i, j;
2914 
2915 	if (hist_data->n_fields - hist_data->n_vals != n_keys)
2916 		return false;
2917 
2918 	i = hist_data->n_vals;
2919 	j = target_hist_data->n_vals;
2920 
2921 	for (n = 0; n < n_keys; n++) {
2922 		hist_field = hist_data->fields[i + n];
2923 		target_hist_field = target_hist_data->fields[j + n];
2924 
2925 		if (strcmp(hist_field->type, target_hist_field->type) != 0)
2926 			return false;
2927 		if (hist_field->size != target_hist_field->size)
2928 			return false;
2929 		if (hist_field->is_signed != target_hist_field->is_signed)
2930 			return false;
2931 	}
2932 
2933 	return true;
2934 }
2935 
2936 static struct hist_trigger_data *
2937 find_compatible_hist(struct hist_trigger_data *target_hist_data,
2938 		     struct trace_event_file *file)
2939 {
2940 	struct hist_trigger_data *hist_data;
2941 	struct event_trigger_data *test;
2942 	unsigned int n_keys;
2943 
2944 	lockdep_assert_held(&event_mutex);
2945 
2946 	n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
2947 
2948 	list_for_each_entry(test, &file->triggers, list) {
2949 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
2950 			hist_data = test->private_data;
2951 
2952 			if (compatible_keys(target_hist_data, hist_data, n_keys))
2953 				return hist_data;
2954 		}
2955 	}
2956 
2957 	return NULL;
2958 }
2959 
2960 static struct trace_event_file *event_file(struct trace_array *tr,
2961 					   char *system, char *event_name)
2962 {
2963 	struct trace_event_file *file;
2964 
2965 	file = __find_event_file(tr, system, event_name);
2966 	if (!file)
2967 		return ERR_PTR(-EINVAL);
2968 
2969 	return file;
2970 }
2971 
2972 static struct hist_field *
2973 find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
2974 			 char *system, char *event_name, char *field_name)
2975 {
2976 	struct hist_field *event_var;
2977 	char *synthetic_name;
2978 	struct seq_buf s;
2979 
2980 	synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
2981 	if (!synthetic_name)
2982 		return ERR_PTR(-ENOMEM);
2983 
2984 	seq_buf_init(&s, synthetic_name, MAX_FILTER_STR_VAL);
2985 	seq_buf_printf(&s, "synthetic_%s", field_name);
2986 
2987 	/* Terminate synthetic_name with a NUL. */
2988 	seq_buf_str(&s);
2989 
2990 	if (seq_buf_has_overflowed(&s)) {
2991 		kfree(synthetic_name);
2992 		return ERR_PTR(-E2BIG);
2993 	}
2994 
2995 	event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);
2996 
2997 	kfree(synthetic_name);
2998 
2999 	return event_var;
3000 }
3001 
3002 /**
3003  * create_field_var_hist - Automatically create a histogram and var for a field
3004  * @target_hist_data: The target hist trigger
3005  * @subsys_name: Optional subsystem name
3006  * @event_name: Optional event name
3007  * @field_name: The name of the field (and the resulting variable)
3008  *
3009  * Hist trigger actions fetch data from variables, not directly from
3010  * events.  However, for convenience, users are allowed to directly
3011  * specify an event field in an action, which will be automatically
3012  * converted into a variable on their behalf.
3013  *
3014  * If a user specifies a field on an event that isn't the event the
3015  * histogram currently being defined (the target event histogram), the
3016  * only way that can be accomplished is if a new hist trigger is
3017  * created and the field variable defined on that.
3018  *
3019  * This function creates a new histogram compatible with the target
3020  * event (meaning a histogram with the same key as the target
3021  * histogram), and creates a variable for the specified field, but
3022  * with 'synthetic_' prepended to the variable name in order to avoid
3023  * collision with normal field variables.
3024  *
3025  * Return: The variable created for the field.
3026  */
3027 static struct hist_field *
3028 create_field_var_hist(struct hist_trigger_data *target_hist_data,
3029 		      char *subsys_name, char *event_name, char *field_name)
3030 {
3031 	struct trace_array *tr = target_hist_data->event_file->tr;
3032 	struct hist_trigger_data *hist_data;
3033 	unsigned int i, n, first = true;
3034 	struct field_var_hist *var_hist;
3035 	struct trace_event_file *file;
3036 	struct hist_field *key_field;
3037 	struct hist_field *event_var;
3038 	char *saved_filter;
3039 	struct seq_buf s;
3040 	char *cmd;
3041 	int ret;
3042 
3043 	if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
3044 		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
3045 		return ERR_PTR(-EINVAL);
3046 	}
3047 
3048 	file = event_file(tr, subsys_name, event_name);
3049 
3050 	if (IS_ERR(file)) {
3051 		hist_err(tr, HIST_ERR_EVENT_FILE_NOT_FOUND, errpos(field_name));
3052 		ret = PTR_ERR(file);
3053 		return ERR_PTR(ret);
3054 	}
3055 
3056 	/*
3057 	 * Look for a histogram compatible with target.  We'll use the
3058 	 * found histogram specification to create a new matching
3059 	 * histogram with our variable on it.  target_hist_data is not
3060 	 * yet a registered histogram so we can't use that.
3061 	 */
3062 	hist_data = find_compatible_hist(target_hist_data, file);
3063 	if (!hist_data) {
3064 		hist_err(tr, HIST_ERR_HIST_NOT_FOUND, errpos(field_name));
3065 		return ERR_PTR(-EINVAL);
3066 	}
3067 
3068 	/* See if a synthetic field variable has already been created */
3069 	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
3070 					     event_name, field_name);
3071 	if (!IS_ERR_OR_NULL(event_var))
3072 		return event_var;
3073 
3074 	var_hist = kzalloc_obj(*var_hist);
3075 	if (!var_hist)
3076 		return ERR_PTR(-ENOMEM);
3077 
3078 	cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
3079 	if (!cmd) {
3080 		kfree(var_hist);
3081 		return ERR_PTR(-ENOMEM);
3082 	}
3083 
3084 	seq_buf_init(&s, cmd, MAX_FILTER_STR_VAL);
3085 
3086 	/* Use the same keys as the compatible histogram */
3087 	seq_buf_puts(&s, "keys=");
3088 
3089 	for_each_hist_key_field(i, hist_data) {
3090 		key_field = hist_data->fields[i];
3091 		if (!first)
3092 			seq_buf_putc(&s, ',');
3093 		seq_buf_puts(&s, key_field->field->name);
3094 		first = false;
3095 	}
3096 
3097 	/* Create the synthetic field variable specification */
3098 	seq_buf_printf(&s, ":synthetic_%s=%s", field_name, field_name);
3099 
3100 	/* Use the same filter as the compatible histogram */
3101 	saved_filter = find_trigger_filter(hist_data, file);
3102 	if (saved_filter)
3103 		seq_buf_printf(&s, " if %s", saved_filter);
3104 
3105 	/* Terminate cmd with a NUL. */
3106 	seq_buf_str(&s);
3107 
3108 	if (seq_buf_has_overflowed(&s)) {
3109 		kfree(cmd);
3110 		kfree(var_hist);
3111 		return ERR_PTR(-E2BIG);
3112 	}
3113 
3114 	var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
3115 	if (!var_hist->cmd) {
3116 		kfree(cmd);
3117 		kfree(var_hist);
3118 		return ERR_PTR(-ENOMEM);
3119 	}
3120 
3121 	/* Save the compatible histogram information */
3122 	var_hist->hist_data = hist_data;
3123 
3124 	/* Create the new histogram with our variable */
3125 	ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
3126 				       "", "hist", cmd);
3127 	if (ret) {
3128 		kfree(cmd);
3129 		kfree(var_hist->cmd);
3130 		kfree(var_hist);
3131 		hist_err(tr, HIST_ERR_HIST_CREATE_FAIL, errpos(field_name));
3132 		return ERR_PTR(ret);
3133 	}
3134 
3135 	kfree(cmd);
3136 
3137 	/* If we can't find the variable, something went wrong */
3138 	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
3139 					     event_name, field_name);
3140 	if (IS_ERR_OR_NULL(event_var)) {
3141 		kfree(var_hist->cmd);
3142 		kfree(var_hist);
3143 		hist_err(tr, HIST_ERR_SYNTH_VAR_NOT_FOUND, errpos(field_name));
3144 		return ERR_PTR(-EINVAL);
3145 	}
3146 
3147 	n = target_hist_data->n_field_var_hists;
3148 	target_hist_data->field_var_hists[n] = var_hist;
3149 	target_hist_data->n_field_var_hists++;
3150 
3151 	return event_var;
3152 }
3153 
3154 static struct hist_field *
3155 find_target_event_var(struct hist_trigger_data *hist_data,
3156 		      char *subsys_name, char *event_name, char *var_name)
3157 {
3158 	struct trace_event_file *file = hist_data->event_file;
3159 	struct hist_field *hist_field = NULL;
3160 
3161 	if (subsys_name) {
3162 		struct trace_event_call *call;
3163 
3164 		if (!event_name)
3165 			return NULL;
3166 
3167 		call = file->event_call;
3168 
3169 		if (strcmp(subsys_name, call->class->system) != 0)
3170 			return NULL;
3171 
3172 		if (strcmp(event_name, trace_event_name(call)) != 0)
3173 			return NULL;
3174 	}
3175 
3176 	hist_field = find_var_field(hist_data, var_name);
3177 
3178 	return hist_field;
3179 }
3180 
3181 static inline void __update_field_vars(struct tracing_map_elt *elt,
3182 				       struct trace_buffer *buffer,
3183 				       struct ring_buffer_event *rbe,
3184 				       void *rec,
3185 				       struct field_var **field_vars,
3186 				       unsigned int n_field_vars,
3187 				       unsigned int field_var_str_start)
3188 {
3189 	struct hist_elt_data *elt_data = elt->private_data;
3190 	unsigned int i, j, var_idx;
3191 	u64 var_val;
3192 
3193 	/* Make sure stacktrace can fit in the string variable length */
3194 	BUILD_BUG_ON((HIST_STACKTRACE_DEPTH + 1) * sizeof(long) > STR_VAR_LEN_MAX);
3195 
3196 	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
3197 		struct field_var *field_var = field_vars[i];
3198 		struct hist_field *var = field_var->var;
3199 		struct hist_field *val = field_var->val;
3200 
3201 		var_val = hist_fn_call(val, elt, buffer, rbe, rec);
3202 		var_idx = var->var.idx;
3203 
3204 		if (val->flags & (HIST_FIELD_FL_STRING |
3205 				  HIST_FIELD_FL_STACKTRACE)) {
3206 			char *str = elt_data->field_var_str[j++];
3207 			char *val_str = (char *)(uintptr_t)var_val;
3208 			unsigned int size;
3209 
3210 			if (val->flags & HIST_FIELD_FL_STRING) {
3211 				size = min(val->size, STR_VAR_LEN_MAX);
3212 				strscpy(str, val_str, size);
3213 			} else {
3214 				char *stack_start = str + sizeof(unsigned long);
3215 				int e;
3216 
3217 				e = stack_trace_save((void *)stack_start,
3218 						     HIST_STACKTRACE_DEPTH,
3219 						     HIST_STACKTRACE_SKIP);
3220 				if (e < HIST_STACKTRACE_DEPTH - 1)
3221 					((unsigned long *)stack_start)[e] = 0;
3222 				*((unsigned long *)str) = e;
3223 			}
3224 			var_val = (u64)(uintptr_t)str;
3225 		}
3226 		tracing_map_set_var(elt, var_idx, var_val);
3227 	}
3228 }
3229 
3230 static void update_field_vars(struct hist_trigger_data *hist_data,
3231 			      struct tracing_map_elt *elt,
3232 			      struct trace_buffer *buffer,
3233 			      struct ring_buffer_event *rbe,
3234 			      void *rec)
3235 {
3236 	__update_field_vars(elt, buffer, rbe, rec, hist_data->field_vars,
3237 			    hist_data->n_field_vars, 0);
3238 }
3239 
3240 static void save_track_data_vars(struct hist_trigger_data *hist_data,
3241 				 struct tracing_map_elt *elt,
3242 				 struct trace_buffer *buffer,  void *rec,
3243 				 struct ring_buffer_event *rbe, void *key,
3244 				 struct action_data *data, u64 *var_ref_vals)
3245 {
3246 	__update_field_vars(elt, buffer, rbe, rec, hist_data->save_vars,
3247 			    hist_data->n_save_vars, hist_data->n_field_var_str);
3248 }
3249 
3250 static struct hist_field *create_var(struct hist_trigger_data *hist_data,
3251 				     struct trace_event_file *file,
3252 				     char *name, int size, const char *type)
3253 {
3254 	struct hist_field *var;
3255 	int idx;
3256 
3257 	if (find_var(hist_data, file, name) && !hist_data->remove) {
3258 		var = ERR_PTR(-EINVAL);
3259 		goto out;
3260 	}
3261 
3262 	var = kzalloc_obj(struct hist_field);
3263 	if (!var) {
3264 		var = ERR_PTR(-ENOMEM);
3265 		goto out;
3266 	}
3267 
3268 	idx = tracing_map_add_var(hist_data->map);
3269 	if (idx < 0) {
3270 		kfree(var);
3271 		var = ERR_PTR(-EINVAL);
3272 		goto out;
3273 	}
3274 
3275 	var->flags = HIST_FIELD_FL_VAR;
3276 	var->var.idx = idx;
3277 	var->var.hist_data = var->hist_data = hist_data;
3278 	var->size = size;
3279 	var->var.name = kstrdup(name, GFP_KERNEL);
3280 	var->type = kstrdup_const(type, GFP_KERNEL);
3281 	if (!var->var.name || !var->type) {
3282 		kfree_const(var->type);
3283 		kfree(var->var.name);
3284 		kfree(var);
3285 		var = ERR_PTR(-ENOMEM);
3286 	}
3287  out:
3288 	return var;
3289 }
3290 
3291 static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
3292 					  struct trace_event_file *file,
3293 					  char *field_name)
3294 {
3295 	struct hist_field *val = NULL, *var = NULL;
3296 	unsigned long flags = HIST_FIELD_FL_VAR;
3297 	struct trace_array *tr = file->tr;
3298 	struct field_var *field_var;
3299 	int ret = 0;
3300 
3301 	if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
3302 		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
3303 		ret = -EINVAL;
3304 		goto err;
3305 	}
3306 
3307 	val = parse_atom(hist_data, file, field_name, &flags, NULL);
3308 	if (IS_ERR(val)) {
3309 		hist_err(tr, HIST_ERR_FIELD_VAR_PARSE_FAIL, errpos(field_name));
3310 		ret = PTR_ERR(val);
3311 		goto err;
3312 	}
3313 
3314 	var = create_var(hist_data, file, field_name, val->size, val->type);
3315 	if (IS_ERR(var)) {
3316 		hist_err(tr, HIST_ERR_VAR_CREATE_FIND_FAIL, errpos(field_name));
3317 		destroy_hist_field(val, 0);
3318 		ret = PTR_ERR(var);
3319 		goto err;
3320 	}
3321 
3322 	field_var = kzalloc_obj(struct field_var);
3323 	if (!field_var) {
3324 		destroy_hist_field(val, 0);
3325 		kfree_const(var->type);
3326 		kfree(var->var.name);
3327 		kfree(var);
3328 		ret =  -ENOMEM;
3329 		goto err;
3330 	}
3331 
3332 	field_var->var = var;
3333 	field_var->val = val;
3334  out:
3335 	return field_var;
3336  err:
3337 	field_var = ERR_PTR(ret);
3338 	goto out;
3339 }
3340 
3341 /**
3342  * create_target_field_var - Automatically create a variable for a field
3343  * @target_hist_data: The target hist trigger
3344  * @subsys_name: Optional subsystem name
3345  * @event_name: Optional event name
3346  * @var_name: The name of the field (and the resulting variable)
3347  *
3348  * Hist trigger actions fetch data from variables, not directly from
3349  * events.  However, for convenience, users are allowed to directly
3350  * specify an event field in an action, which will be automatically
3351  * converted into a variable on their behalf.
3352  *
3353  * This function creates a field variable with the name var_name on
3354  * the hist trigger currently being defined on the target event.  If
3355  * subsys_name and event_name are specified, this function simply
3356  * verifies that they do in fact match the target event subsystem and
3357  * event name.
3358  *
3359  * Return: The variable created for the field.
3360  */
3361 static struct field_var *
3362 create_target_field_var(struct hist_trigger_data *target_hist_data,
3363 			char *subsys_name, char *event_name, char *var_name)
3364 {
3365 	struct trace_event_file *file = target_hist_data->event_file;
3366 
3367 	if (subsys_name) {
3368 		struct trace_event_call *call;
3369 
3370 		if (!event_name)
3371 			return NULL;
3372 
3373 		call = file->event_call;
3374 
3375 		if (strcmp(subsys_name, call->class->system) != 0)
3376 			return NULL;
3377 
3378 		if (strcmp(event_name, trace_event_name(call)) != 0)
3379 			return NULL;
3380 	}
3381 
3382 	return create_field_var(target_hist_data, file, var_name);
3383 }
3384 
3385 static bool check_track_val_max(u64 track_val, u64 var_val)
3386 {
3387 	if (var_val <= track_val)
3388 		return false;
3389 
3390 	return true;
3391 }
3392 
3393 static bool check_track_val_changed(u64 track_val, u64 var_val)
3394 {
3395 	if (var_val == track_val)
3396 		return false;
3397 
3398 	return true;
3399 }
3400 
3401 static u64 get_track_val(struct hist_trigger_data *hist_data,
3402 			 struct tracing_map_elt *elt,
3403 			 struct action_data *data)
3404 {
3405 	unsigned int track_var_idx = data->track_data.track_var->var.idx;
3406 	u64 track_val;
3407 
3408 	track_val = tracing_map_read_var(elt, track_var_idx);
3409 
3410 	return track_val;
3411 }
3412 
3413 static void save_track_val(struct hist_trigger_data *hist_data,
3414 			   struct tracing_map_elt *elt,
3415 			   struct action_data *data, u64 var_val)
3416 {
3417 	unsigned int track_var_idx = data->track_data.track_var->var.idx;
3418 
3419 	tracing_map_set_var(elt, track_var_idx, var_val);
3420 }
3421 
3422 static void save_track_data(struct hist_trigger_data *hist_data,
3423 			    struct tracing_map_elt *elt,
3424 			    struct trace_buffer *buffer, void *rec,
3425 			    struct ring_buffer_event *rbe, void *key,
3426 			    struct action_data *data, u64 *var_ref_vals)
3427 {
3428 	if (data->track_data.save_data)
3429 		data->track_data.save_data(hist_data, elt, buffer, rec, rbe,
3430 					   key, data, var_ref_vals);
3431 }
3432 
3433 static bool check_track_val(struct tracing_map_elt *elt,
3434 			    struct action_data *data,
3435 			    u64 var_val)
3436 {
3437 	struct hist_trigger_data *hist_data;
3438 	u64 track_val;
3439 
3440 	hist_data = data->track_data.track_var->hist_data;
3441 	track_val = get_track_val(hist_data, elt, data);
3442 
3443 	return data->track_data.check_val(track_val, var_val);
3444 }
3445 
3446 #ifdef CONFIG_TRACER_SNAPSHOT
3447 static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3448 {
3449 	/* called with tr->max_lock held */
3450 	struct track_data *track_data = tr->cond_snapshot->cond_data;
3451 	struct hist_elt_data *elt_data, *track_elt_data;
3452 	struct snapshot_context *context = cond_data;
3453 	struct action_data *action;
3454 	u64 track_val;
3455 
3456 	if (!track_data)
3457 		return false;
3458 
3459 	action = track_data->action_data;
3460 
3461 	track_val = get_track_val(track_data->hist_data, context->elt,
3462 				  track_data->action_data);
3463 
3464 	if (!action->track_data.check_val(track_data->track_val, track_val))
3465 		return false;
3466 
3467 	track_data->track_val = track_val;
3468 	memcpy(track_data->key, context->key, track_data->key_len);
3469 
3470 	elt_data = context->elt->private_data;
3471 	track_elt_data = track_data->elt.private_data;
3472 	if (elt_data->comm)
3473 		strscpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
3474 
3475 	track_data->updated = true;
3476 
3477 	return true;
3478 }
3479 
3480 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3481 				     struct tracing_map_elt *elt,
3482 				     struct trace_buffer *buffer, void *rec,
3483 				     struct ring_buffer_event *rbe, void *key,
3484 				     struct action_data *data,
3485 				     u64 *var_ref_vals)
3486 {
3487 	struct trace_event_file *file = hist_data->event_file;
3488 	struct snapshot_context context;
3489 
3490 	context.elt = elt;
3491 	context.key = key;
3492 
3493 	tracing_snapshot_cond(file->tr, &context);
3494 }
3495 
3496 static void hist_trigger_print_key(struct seq_file *m,
3497 				   struct hist_trigger_data *hist_data,
3498 				   void *key,
3499 				   struct tracing_map_elt *elt);
3500 
3501 static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
3502 {
3503 	unsigned int i;
3504 
3505 	if (!hist_data->n_actions)
3506 		return NULL;
3507 
3508 	for (i = 0; i < hist_data->n_actions; i++) {
3509 		struct action_data *data = hist_data->actions[i];
3510 
3511 		if (data->action == ACTION_SNAPSHOT)
3512 			return data;
3513 	}
3514 
3515 	return NULL;
3516 }
3517 
3518 static void track_data_snapshot_print(struct seq_file *m,
3519 				      struct hist_trigger_data *hist_data)
3520 {
3521 	struct trace_event_file *file = hist_data->event_file;
3522 	struct track_data *track_data;
3523 	struct action_data *action;
3524 
3525 	track_data = tracing_cond_snapshot_data(file->tr);
3526 	if (!track_data)
3527 		return;
3528 
3529 	if (!track_data->updated)
3530 		return;
3531 
3532 	action = snapshot_action(hist_data);
3533 	if (!action)
3534 		return;
3535 
3536 	seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
3537 	seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
3538 		   action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
3539 		   action->track_data.var_str, track_data->track_val);
3540 
3541 	seq_puts(m, "\ttriggered by event with key: ");
3542 	hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
3543 	seq_putc(m, '\n');
3544 }
3545 #else
3546 static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
3547 {
3548 	return false;
3549 }
3550 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
3551 				     struct tracing_map_elt *elt,
3552 				     struct trace_buffer *buffer, void *rec,
3553 				     struct ring_buffer_event *rbe, void *key,
3554 				     struct action_data *data,
3555 				     u64 *var_ref_vals) {}
3556 static void track_data_snapshot_print(struct seq_file *m,
3557 				      struct hist_trigger_data *hist_data) {}
3558 #endif /* CONFIG_TRACER_SNAPSHOT */
3559 
3560 static void track_data_print(struct seq_file *m,
3561 			     struct hist_trigger_data *hist_data,
3562 			     struct tracing_map_elt *elt,
3563 			     struct action_data *data)
3564 {
3565 	u64 track_val = get_track_val(hist_data, elt, data);
3566 	unsigned int i, save_var_idx;
3567 
3568 	if (data->handler == HANDLER_ONMAX)
3569 		seq_printf(m, "\n\tmax: %10llu", track_val);
3570 	else if (data->handler == HANDLER_ONCHANGE)
3571 		seq_printf(m, "\n\tchanged: %10llu", track_val);
3572 
3573 	if (data->action == ACTION_SNAPSHOT)
3574 		return;
3575 
3576 	for (i = 0; i < hist_data->n_save_vars; i++) {
3577 		struct hist_field *save_val = hist_data->save_vars[i]->val;
3578 		struct hist_field *save_var = hist_data->save_vars[i]->var;
3579 		u64 val;
3580 
3581 		save_var_idx = save_var->var.idx;
3582 
3583 		val = tracing_map_read_var(elt, save_var_idx);
3584 
3585 		if (save_val->flags & HIST_FIELD_FL_STRING) {
3586 			seq_printf(m, "  %s: %-32s", save_var->var.name,
3587 				   (char *)(uintptr_t)(val));
3588 		} else
3589 			seq_printf(m, "  %s: %10llu", save_var->var.name, val);
3590 	}
3591 }
3592 
3593 static void ontrack_action(struct hist_trigger_data *hist_data,
3594 			   struct tracing_map_elt *elt,
3595 			   struct trace_buffer *buffer, void *rec,
3596 			   struct ring_buffer_event *rbe, void *key,
3597 			   struct action_data *data, u64 *var_ref_vals)
3598 {
3599 	u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];
3600 
3601 	if (check_track_val(elt, data, var_val)) {
3602 		save_track_val(hist_data, elt, data, var_val);
3603 		save_track_data(hist_data, elt, buffer, rec, rbe,
3604 				key, data, var_ref_vals);
3605 	}
3606 }
3607 
3608 static void action_data_destroy(struct action_data *data)
3609 {
3610 	unsigned int i;
3611 
3612 	lockdep_assert_held(&event_mutex);
3613 
3614 	kfree(data->action_name);
3615 
3616 	for (i = 0; i < data->n_params; i++)
3617 		kfree(data->params[i]);
3618 
3619 	if (data->synth_event)
3620 		data->synth_event->ref--;
3621 
3622 	kfree(data->synth_event_name);
3623 
3624 	kfree(data);
3625 }
3626 
3627 static void track_data_destroy(struct hist_trigger_data *hist_data,
3628 			       struct action_data *data)
3629 {
3630 	struct trace_event_file *file = hist_data->event_file;
3631 
3632 	destroy_hist_field(data->track_data.track_var, 0);
3633 
3634 	if (data->action == ACTION_SNAPSHOT) {
3635 		struct track_data *track_data;
3636 
3637 		track_data = tracing_cond_snapshot_data(file->tr);
3638 		if (track_data && track_data->hist_data == hist_data) {
3639 			tracing_snapshot_cond_disable(file->tr);
3640 			track_data_free(track_data);
3641 		}
3642 	}
3643 
3644 	kfree(data->track_data.var_str);
3645 
3646 	action_data_destroy(data);
3647 }
3648 
3649 static int action_create(struct hist_trigger_data *hist_data,
3650 			 struct action_data *data);
3651 
3652 static int track_data_create(struct hist_trigger_data *hist_data,
3653 			     struct action_data *data)
3654 {
3655 	struct hist_field *var_field, *ref_field, *track_var = NULL;
3656 	struct trace_event_file *file = hist_data->event_file;
3657 	struct trace_array *tr = file->tr;
3658 	char *track_data_var_str;
3659 	int ret = 0;
3660 
3661 	track_data_var_str = data->track_data.var_str;
3662 	if (track_data_var_str[0] != '$') {
3663 		hist_err(tr, HIST_ERR_ONX_NOT_VAR, errpos(track_data_var_str));
3664 		return -EINVAL;
3665 	}
3666 	track_data_var_str++;
3667 
3668 	var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
3669 	if (!var_field) {
3670 		hist_err(tr, HIST_ERR_ONX_VAR_NOT_FOUND, errpos(track_data_var_str));
3671 		return -EINVAL;
3672 	}
3673 
3674 	ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
3675 	if (!ref_field)
3676 		return -ENOMEM;
3677 
3678 	data->track_data.var_ref = ref_field;
3679 
3680 	if (data->handler == HANDLER_ONMAX)
3681 		track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
3682 	if (IS_ERR(track_var)) {
3683 		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3684 		ret = PTR_ERR(track_var);
3685 		goto out;
3686 	}
3687 
3688 	if (data->handler == HANDLER_ONCHANGE)
3689 		track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
3690 	if (IS_ERR(track_var)) {
3691 		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
3692 		ret = PTR_ERR(track_var);
3693 		goto out;
3694 	}
3695 	data->track_data.track_var = track_var;
3696 
3697 	ret = action_create(hist_data, data);
3698  out:
3699 	return ret;
3700 }
3701 
3702 static int parse_action_params(struct trace_array *tr, char *params,
3703 			       struct action_data *data)
3704 {
3705 	char *param, *saved_param;
3706 	bool first_param = true;
3707 	int ret = 0;
3708 
3709 	while (params) {
3710 		if (data->n_params >= SYNTH_FIELDS_MAX) {
3711 			hist_err(tr, HIST_ERR_TOO_MANY_PARAMS, 0);
3712 			ret = -EINVAL;
3713 			goto out;
3714 		}
3715 
3716 		param = strsep(&params, ",");
3717 		if (!param) {
3718 			hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, 0);
3719 			ret = -EINVAL;
3720 			goto out;
3721 		}
3722 
3723 		param = strstrip(param);
3724 		if (strlen(param) < 2) {
3725 			hist_err(tr, HIST_ERR_INVALID_PARAM, errpos(param));
3726 			ret = -EINVAL;
3727 			goto out;
3728 		}
3729 
3730 		saved_param = kstrdup(param, GFP_KERNEL);
3731 		if (!saved_param) {
3732 			ret = -ENOMEM;
3733 			goto out;
3734 		}
3735 
3736 		if (first_param && data->use_trace_keyword) {
3737 			data->synth_event_name = saved_param;
3738 			first_param = false;
3739 			continue;
3740 		}
3741 		first_param = false;
3742 
3743 		data->params[data->n_params++] = saved_param;
3744 	}
3745  out:
3746 	return ret;
3747 }
3748 
3749 static int action_parse(struct trace_array *tr, char *str, struct action_data *data,
3750 			enum handler_id handler)
3751 {
3752 	char *action_name;
3753 	int ret = 0;
3754 
3755 	strsep(&str, ".");
3756 	if (!str) {
3757 		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3758 		ret = -EINVAL;
3759 		goto out;
3760 	}
3761 
3762 	action_name = strsep(&str, "(");
3763 	if (!action_name || !str) {
3764 		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
3765 		ret = -EINVAL;
3766 		goto out;
3767 	}
3768 
3769 	if (str_has_prefix(action_name, "save")) {
3770 		char *params = strsep(&str, ")");
3771 
3772 		if (!params) {
3773 			hist_err(tr, HIST_ERR_NO_SAVE_PARAMS, 0);
3774 			ret = -EINVAL;
3775 			goto out;
3776 		}
3777 
3778 		ret = parse_action_params(tr, params, data);
3779 		if (ret)
3780 			goto out;
3781 
3782 		if (handler == HANDLER_ONMAX)
3783 			data->track_data.check_val = check_track_val_max;
3784 		else if (handler == HANDLER_ONCHANGE)
3785 			data->track_data.check_val = check_track_val_changed;
3786 		else {
3787 			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3788 			ret = -EINVAL;
3789 			goto out;
3790 		}
3791 
3792 		data->track_data.save_data = save_track_data_vars;
3793 		data->fn = ontrack_action;
3794 		data->action = ACTION_SAVE;
3795 	} else if (str_has_prefix(action_name, "snapshot")) {
3796 		char *params = strsep(&str, ")");
3797 
3798 		if (!str) {
3799 			hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(params));
3800 			ret = -EINVAL;
3801 			goto out;
3802 		}
3803 
3804 		if (handler == HANDLER_ONMAX)
3805 			data->track_data.check_val = check_track_val_max;
3806 		else if (handler == HANDLER_ONCHANGE)
3807 			data->track_data.check_val = check_track_val_changed;
3808 		else {
3809 			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
3810 			ret = -EINVAL;
3811 			goto out;
3812 		}
3813 
3814 		data->track_data.save_data = save_track_data_snapshot;
3815 		data->fn = ontrack_action;
3816 		data->action = ACTION_SNAPSHOT;
3817 	} else {
3818 		char *params = strsep(&str, ")");
3819 
3820 		if (str_has_prefix(action_name, "trace"))
3821 			data->use_trace_keyword = true;
3822 
3823 		if (params) {
3824 			ret = parse_action_params(tr, params, data);
3825 			if (ret)
3826 				goto out;
3827 		}
3828 
3829 		if (handler == HANDLER_ONMAX)
3830 			data->track_data.check_val = check_track_val_max;
3831 		else if (handler == HANDLER_ONCHANGE)
3832 			data->track_data.check_val = check_track_val_changed;
3833 
3834 		if (handler != HANDLER_ONMATCH) {
3835 			data->track_data.save_data = action_trace;
3836 			data->fn = ontrack_action;
3837 		} else
3838 			data->fn = action_trace;
3839 
3840 		data->action = ACTION_TRACE;
3841 	}
3842 
3843 	data->action_name = kstrdup(action_name, GFP_KERNEL);
3844 	if (!data->action_name) {
3845 		ret = -ENOMEM;
3846 		goto out;
3847 	}
3848 
3849 	data->handler = handler;
3850  out:
3851 	return ret;
3852 }
3853 
3854 static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
3855 					    char *str, enum handler_id handler)
3856 {
3857 	struct action_data *data;
3858 	int ret = -EINVAL;
3859 	char *var_str;
3860 
3861 	data = kzalloc_obj(*data);
3862 	if (!data)
3863 		return ERR_PTR(-ENOMEM);
3864 
3865 	var_str = strsep(&str, ")");
3866 	if (!var_str || !str) {
3867 		ret = -EINVAL;
3868 		goto free;
3869 	}
3870 
3871 	data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
3872 	if (!data->track_data.var_str) {
3873 		ret = -ENOMEM;
3874 		goto free;
3875 	}
3876 
3877 	ret = action_parse(hist_data->event_file->tr, str, data, handler);
3878 	if (ret)
3879 		goto free;
3880  out:
3881 	return data;
3882  free:
3883 	track_data_destroy(hist_data, data);
3884 	data = ERR_PTR(ret);
3885 	goto out;
3886 }
3887 
3888 static void onmatch_destroy(struct action_data *data)
3889 {
3890 	kfree(data->match_data.event);
3891 	kfree(data->match_data.event_system);
3892 
3893 	action_data_destroy(data);
3894 }
3895 
3896 static void destroy_field_var(struct field_var *field_var)
3897 {
3898 	if (!field_var)
3899 		return;
3900 
3901 	destroy_hist_field(field_var->var, 0);
3902 	destroy_hist_field(field_var->val, 0);
3903 
3904 	kfree(field_var);
3905 }
3906 
3907 static void destroy_field_vars(struct hist_trigger_data *hist_data)
3908 {
3909 	unsigned int i;
3910 
3911 	for (i = 0; i < hist_data->n_field_vars; i++)
3912 		destroy_field_var(hist_data->field_vars[i]);
3913 
3914 	for (i = 0; i < hist_data->n_save_vars; i++)
3915 		destroy_field_var(hist_data->save_vars[i]);
3916 }
3917 
3918 static void save_field_var(struct hist_trigger_data *hist_data,
3919 			   struct field_var *field_var)
3920 {
3921 	hist_data->field_vars[hist_data->n_field_vars++] = field_var;
3922 
3923 	/* Stack traces are saved in the string storage too */
3924 	if (field_var->val->flags & (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
3925 		hist_data->n_field_var_str++;
3926 }
3927 
3928 
3929 static int check_synth_field(struct synth_event *event,
3930 			     struct hist_field *hist_field,
3931 			     unsigned int field_pos)
3932 {
3933 	struct synth_field *field;
3934 
3935 	if (field_pos >= event->n_fields)
3936 		return -EINVAL;
3937 
3938 	field = event->fields[field_pos];
3939 
3940 	/*
3941 	 * A dynamic string synth field can accept static or
3942 	 * dynamic. A static string synth field can only accept a
3943 	 * same-sized static string, which is checked for later.
3944 	 */
3945 	if (strstr(hist_field->type, "char[") && field->is_string
3946 	    && field->is_dynamic)
3947 		return 0;
3948 
3949 	if (strstr(hist_field->type, "long[") && field->is_stack)
3950 		return 0;
3951 
3952 	if (strcmp(field->type, hist_field->type) != 0) {
3953 		if (field->size != hist_field->size ||
3954 		    (!field->is_string && field->is_signed != hist_field->is_signed))
3955 			return -EINVAL;
3956 	}
3957 
3958 	return 0;
3959 }
3960 
3961 static struct hist_field *
3962 trace_action_find_var(struct hist_trigger_data *hist_data,
3963 		      struct action_data *data,
3964 		      char *system, char *event, char *var)
3965 {
3966 	struct trace_array *tr = hist_data->event_file->tr;
3967 	struct hist_field *hist_field;
3968 
3969 	var++; /* skip '$' */
3970 
3971 	hist_field = find_target_event_var(hist_data, system, event, var);
3972 	if (!hist_field) {
3973 		if (!system && data->handler == HANDLER_ONMATCH) {
3974 			system = data->match_data.event_system;
3975 			event = data->match_data.event;
3976 		}
3977 
3978 		hist_field = find_event_var(hist_data, system, event, var);
3979 	}
3980 
3981 	if (!hist_field)
3982 		hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, errpos(var));
3983 
3984 	return hist_field;
3985 }
3986 
3987 static struct hist_field *
3988 trace_action_create_field_var(struct hist_trigger_data *hist_data,
3989 			      struct action_data *data, char *system,
3990 			      char *event, char *var)
3991 {
3992 	struct hist_field *hist_field = NULL;
3993 	struct field_var *field_var;
3994 
3995 	/*
3996 	 * First try to create a field var on the target event (the
3997 	 * currently being defined).  This will create a variable for
3998 	 * unqualified fields on the target event, or if qualified,
3999 	 * target fields that have qualified names matching the target.
4000 	 */
4001 	field_var = create_target_field_var(hist_data, system, event, var);
4002 
4003 	if (field_var && !IS_ERR(field_var)) {
4004 		save_field_var(hist_data, field_var);
4005 		hist_field = field_var->var;
4006 	} else {
4007 		field_var = NULL;
4008 		/*
4009 		 * If no explicit system.event is specified, default to
4010 		 * looking for fields on the onmatch(system.event.xxx)
4011 		 * event.
4012 		 */
4013 		if (!system && data->handler == HANDLER_ONMATCH) {
4014 			system = data->match_data.event_system;
4015 			event = data->match_data.event;
4016 		}
4017 
4018 		if (!event)
4019 			goto free;
4020 		/*
4021 		 * At this point, we're looking at a field on another
4022 		 * event.  Because we can't modify a hist trigger on
4023 		 * another event to add a variable for a field, we need
4024 		 * to create a new trigger on that event and create the
4025 		 * variable at the same time.
4026 		 */
4027 		hist_field = create_field_var_hist(hist_data, system, event, var);
4028 		if (IS_ERR(hist_field))
4029 			goto free;
4030 	}
4031  out:
4032 	return hist_field;
4033  free:
4034 	destroy_field_var(field_var);
4035 	hist_field = NULL;
4036 	goto out;
4037 }
4038 
4039 static int trace_action_create(struct hist_trigger_data *hist_data,
4040 			       struct action_data *data)
4041 {
4042 	struct trace_array *tr = hist_data->event_file->tr;
4043 	char *event_name, *param, *system = NULL;
4044 	struct hist_field *hist_field, *var_ref;
4045 	unsigned int i;
4046 	unsigned int field_pos = 0;
4047 	struct synth_event *event;
4048 	char *synth_event_name;
4049 	int var_ref_idx, ret = 0;
4050 
4051 	lockdep_assert_held(&event_mutex);
4052 
4053 	/* Sanity check to avoid out-of-bound write on 'data->var_ref_idx' */
4054 	if (data->n_params > SYNTH_FIELDS_MAX)
4055 		return -EINVAL;
4056 
4057 	if (data->use_trace_keyword)
4058 		synth_event_name = data->synth_event_name;
4059 	else
4060 		synth_event_name = data->action_name;
4061 
4062 	event = find_synth_event(synth_event_name);
4063 	if (!event) {
4064 		hist_err(tr, HIST_ERR_SYNTH_EVENT_NOT_FOUND, errpos(synth_event_name));
4065 		return -EINVAL;
4066 	}
4067 
4068 	event->ref++;
4069 
4070 	for (i = 0; i < data->n_params; i++) {
4071 		char *p;
4072 
4073 		p = param = kstrdup(data->params[i], GFP_KERNEL);
4074 		if (!param) {
4075 			ret = -ENOMEM;
4076 			goto err;
4077 		}
4078 
4079 		system = strsep(&param, ".");
4080 		if (!param) {
4081 			param = (char *)system;
4082 			system = event_name = NULL;
4083 		} else {
4084 			event_name = strsep(&param, ".");
4085 			if (!param) {
4086 				kfree(p);
4087 				ret = -EINVAL;
4088 				goto err;
4089 			}
4090 		}
4091 
4092 		if (param[0] == '$')
4093 			hist_field = trace_action_find_var(hist_data, data,
4094 							   system, event_name,
4095 							   param);
4096 		else
4097 			hist_field = trace_action_create_field_var(hist_data,
4098 								   data,
4099 								   system,
4100 								   event_name,
4101 								   param);
4102 
4103 		if (!hist_field) {
4104 			kfree(p);
4105 			ret = -EINVAL;
4106 			goto err;
4107 		}
4108 
4109 		if (check_synth_field(event, hist_field, field_pos) == 0) {
4110 			var_ref = create_var_ref(hist_data, hist_field,
4111 						 system, event_name);
4112 			if (!var_ref) {
4113 				kfree(p);
4114 				ret = -ENOMEM;
4115 				goto err;
4116 			}
4117 
4118 			var_ref_idx = find_var_ref_idx(hist_data, var_ref);
4119 			if (WARN_ON(var_ref_idx < 0)) {
4120 				kfree(p);
4121 				ret = var_ref_idx;
4122 				goto err;
4123 			}
4124 
4125 			data->var_ref_idx[i] = var_ref_idx;
4126 
4127 			field_pos++;
4128 			kfree(p);
4129 			continue;
4130 		}
4131 
4132 		hist_err(tr, HIST_ERR_SYNTH_TYPE_MISMATCH, errpos(param));
4133 		kfree(p);
4134 		ret = -EINVAL;
4135 		goto err;
4136 	}
4137 
4138 	if (field_pos != event->n_fields) {
4139 		hist_err(tr, HIST_ERR_SYNTH_COUNT_MISMATCH, errpos(event->name));
4140 		ret = -EINVAL;
4141 		goto err;
4142 	}
4143 
4144 	data->synth_event = event;
4145  out:
4146 	return ret;
4147  err:
4148 	event->ref--;
4149 
4150 	goto out;
4151 }
4152 
4153 static int action_create(struct hist_trigger_data *hist_data,
4154 			 struct action_data *data)
4155 {
4156 	struct trace_event_file *file = hist_data->event_file;
4157 	struct trace_array *tr = file->tr;
4158 	struct track_data *track_data;
4159 	struct field_var *field_var;
4160 	unsigned int i;
4161 	char *param;
4162 	int ret = 0;
4163 
4164 	if (data->action == ACTION_TRACE)
4165 		return trace_action_create(hist_data, data);
4166 
4167 	if (data->action == ACTION_SNAPSHOT) {
4168 		track_data = track_data_alloc(hist_data->key_size, data, hist_data);
4169 		if (IS_ERR(track_data)) {
4170 			ret = PTR_ERR(track_data);
4171 			goto out;
4172 		}
4173 
4174 		ret = tracing_snapshot_cond_enable(file->tr, track_data,
4175 						   cond_snapshot_update);
4176 		if (ret)
4177 			track_data_free(track_data);
4178 
4179 		goto out;
4180 	}
4181 
4182 	if (data->action == ACTION_SAVE) {
4183 		if (hist_data->n_save_vars) {
4184 			ret = -EEXIST;
4185 			hist_err(tr, HIST_ERR_TOO_MANY_SAVE_ACTIONS, 0);
4186 			goto out;
4187 		}
4188 
4189 		for (i = 0; i < data->n_params; i++) {
4190 			param = kstrdup(data->params[i], GFP_KERNEL);
4191 			if (!param) {
4192 				ret = -ENOMEM;
4193 				goto out;
4194 			}
4195 
4196 			field_var = create_target_field_var(hist_data, NULL, NULL, param);
4197 			if (IS_ERR(field_var)) {
4198 				hist_err(tr, HIST_ERR_FIELD_VAR_CREATE_FAIL,
4199 					 errpos(param));
4200 				ret = PTR_ERR(field_var);
4201 				kfree(param);
4202 				goto out;
4203 			}
4204 
4205 			hist_data->save_vars[hist_data->n_save_vars++] = field_var;
4206 			if (field_var->val->flags &
4207 			    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
4208 				hist_data->n_save_var_str++;
4209 			kfree(param);
4210 		}
4211 	}
4212  out:
4213 	return ret;
4214 }
4215 
4216 static int onmatch_create(struct hist_trigger_data *hist_data,
4217 			  struct action_data *data)
4218 {
4219 	return action_create(hist_data, data);
4220 }
4221 
4222 static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
4223 {
4224 	char *match_event, *match_event_system;
4225 	struct action_data *data;
4226 	int ret = -EINVAL;
4227 
4228 	data = kzalloc_obj(*data);
4229 	if (!data)
4230 		return ERR_PTR(-ENOMEM);
4231 
4232 	match_event = strsep(&str, ")");
4233 	if (!match_event || !str) {
4234 		hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(match_event));
4235 		goto free;
4236 	}
4237 
4238 	match_event_system = strsep(&match_event, ".");
4239 	if (!match_event) {
4240 		hist_err(tr, HIST_ERR_SUBSYS_NOT_FOUND, errpos(match_event_system));
4241 		goto free;
4242 	}
4243 
4244 	if (IS_ERR(event_file(tr, match_event_system, match_event))) {
4245 		hist_err(tr, HIST_ERR_INVALID_SUBSYS_EVENT, errpos(match_event));
4246 		goto free;
4247 	}
4248 
4249 	data->match_data.event = kstrdup(match_event, GFP_KERNEL);
4250 	if (!data->match_data.event) {
4251 		ret = -ENOMEM;
4252 		goto free;
4253 	}
4254 
4255 	data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
4256 	if (!data->match_data.event_system) {
4257 		ret = -ENOMEM;
4258 		goto free;
4259 	}
4260 
4261 	ret = action_parse(tr, str, data, HANDLER_ONMATCH);
4262 	if (ret)
4263 		goto free;
4264  out:
4265 	return data;
4266  free:
4267 	onmatch_destroy(data);
4268 	data = ERR_PTR(ret);
4269 	goto out;
4270 }
4271 
4272 static int create_hitcount_val(struct hist_trigger_data *hist_data)
4273 {
4274 	hist_data->fields[HITCOUNT_IDX] =
4275 		create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
4276 	if (!hist_data->fields[HITCOUNT_IDX])
4277 		return -ENOMEM;
4278 
4279 	hist_data->n_vals++;
4280 	hist_data->n_fields++;
4281 
4282 	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
4283 		return -EINVAL;
4284 
4285 	return 0;
4286 }
4287 
4288 static int __create_val_field(struct hist_trigger_data *hist_data,
4289 			      unsigned int val_idx,
4290 			      struct trace_event_file *file,
4291 			      char *var_name, char *field_str,
4292 			      unsigned long flags)
4293 {
4294 	struct hist_field *hist_field;
4295 	int ret = 0, n_subexprs = 0;
4296 
4297 	hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs);
4298 	if (IS_ERR(hist_field)) {
4299 		ret = PTR_ERR(hist_field);
4300 		goto out;
4301 	}
4302 
4303 	/* values and variables should not have some modifiers */
4304 	if (hist_field->flags & HIST_FIELD_FL_VAR) {
4305 		/* Variable */
4306 		if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
4307 					 HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2))
4308 			goto err;
4309 	} else {
4310 		/* Value */
4311 		if (hist_field->flags & (HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 |
4312 					 HIST_FIELD_FL_SYM | HIST_FIELD_FL_SYM_OFFSET |
4313 					 HIST_FIELD_FL_SYSCALL | HIST_FIELD_FL_STACKTRACE))
4314 			goto err;
4315 	}
4316 
4317 	hist_data->fields[val_idx] = hist_field;
4318 
4319 	++hist_data->n_vals;
4320 	++hist_data->n_fields;
4321 
4322 	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4323 		ret = -EINVAL;
4324  out:
4325 	return ret;
4326  err:
4327 	hist_err(file->tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
4328 	destroy_hist_field(hist_field, 0);
4329 	return -EINVAL;
4330 }
4331 
4332 static int create_val_field(struct hist_trigger_data *hist_data,
4333 			    unsigned int val_idx,
4334 			    struct trace_event_file *file,
4335 			    char *field_str)
4336 {
4337 	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
4338 		return -EINVAL;
4339 
4340 	return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
4341 }
4342 
4343 static const char no_comm[] = "(no comm)";
4344 
4345 static u64 hist_field_execname(struct hist_field *hist_field,
4346 			       struct tracing_map_elt *elt,
4347 			       struct trace_buffer *buffer,
4348 			       struct ring_buffer_event *rbe,
4349 			       void *event)
4350 {
4351 	struct hist_elt_data *elt_data;
4352 
4353 	if (WARN_ON_ONCE(!elt))
4354 		return (u64)(unsigned long)no_comm;
4355 
4356 	elt_data = elt->private_data;
4357 
4358 	if (WARN_ON_ONCE(!elt_data->comm))
4359 		return (u64)(unsigned long)no_comm;
4360 
4361 	return (u64)(unsigned long)(elt_data->comm);
4362 }
4363 
4364 static u64 hist_field_stack(struct hist_field *hist_field,
4365 			    struct tracing_map_elt *elt,
4366 			    struct trace_buffer *buffer,
4367 			    struct ring_buffer_event *rbe,
4368 			    void *event)
4369 {
4370 	u32 str_item = *(u32 *)(event + hist_field->field->offset);
4371 	int str_loc = str_item & 0xffff;
4372 	char *addr = (char *)(event + str_loc);
4373 
4374 	return (u64)(unsigned long)addr;
4375 }
4376 
4377 static u64 hist_fn_call(struct hist_field *hist_field,
4378 			struct tracing_map_elt *elt,
4379 			struct trace_buffer *buffer,
4380 			struct ring_buffer_event *rbe,
4381 			void *event)
4382 {
4383 	switch (hist_field->fn_num) {
4384 	case HIST_FIELD_FN_VAR_REF:
4385 		return hist_field_var_ref(hist_field, elt, buffer, rbe, event);
4386 	case HIST_FIELD_FN_COUNTER:
4387 		return hist_field_counter(hist_field, elt, buffer, rbe, event);
4388 	case HIST_FIELD_FN_CONST:
4389 		return hist_field_const(hist_field, elt, buffer, rbe, event);
4390 	case HIST_FIELD_FN_LOG2:
4391 		return hist_field_log2(hist_field, elt, buffer, rbe, event);
4392 	case HIST_FIELD_FN_BUCKET:
4393 		return hist_field_bucket(hist_field, elt, buffer, rbe, event);
4394 	case HIST_FIELD_FN_TIMESTAMP:
4395 		return hist_field_timestamp(hist_field, elt, buffer, rbe, event);
4396 	case HIST_FIELD_FN_CPU:
4397 		return hist_field_cpu(hist_field, elt, buffer, rbe, event);
4398 	case HIST_FIELD_FN_COMM:
4399 		return hist_field_comm(hist_field, elt, buffer, rbe, event);
4400 	case HIST_FIELD_FN_STRING:
4401 		return hist_field_string(hist_field, elt, buffer, rbe, event);
4402 	case HIST_FIELD_FN_DYNSTRING:
4403 		return hist_field_dynstring(hist_field, elt, buffer, rbe, event);
4404 	case HIST_FIELD_FN_RELDYNSTRING:
4405 		return hist_field_reldynstring(hist_field, elt, buffer, rbe, event);
4406 	case HIST_FIELD_FN_PSTRING:
4407 		return hist_field_pstring(hist_field, elt, buffer, rbe, event);
4408 	case HIST_FIELD_FN_S64:
4409 		return hist_field_s64(hist_field, elt, buffer, rbe, event);
4410 	case HIST_FIELD_FN_U64:
4411 		return hist_field_u64(hist_field, elt, buffer, rbe, event);
4412 	case HIST_FIELD_FN_S32:
4413 		return hist_field_s32(hist_field, elt, buffer, rbe, event);
4414 	case HIST_FIELD_FN_U32:
4415 		return hist_field_u32(hist_field, elt, buffer, rbe, event);
4416 	case HIST_FIELD_FN_S16:
4417 		return hist_field_s16(hist_field, elt, buffer, rbe, event);
4418 	case HIST_FIELD_FN_U16:
4419 		return hist_field_u16(hist_field, elt, buffer, rbe, event);
4420 	case HIST_FIELD_FN_S8:
4421 		return hist_field_s8(hist_field, elt, buffer, rbe, event);
4422 	case HIST_FIELD_FN_U8:
4423 		return hist_field_u8(hist_field, elt, buffer, rbe, event);
4424 	case HIST_FIELD_FN_UMINUS:
4425 		return hist_field_unary_minus(hist_field, elt, buffer, rbe, event);
4426 	case HIST_FIELD_FN_MINUS:
4427 		return hist_field_minus(hist_field, elt, buffer, rbe, event);
4428 	case HIST_FIELD_FN_PLUS:
4429 		return hist_field_plus(hist_field, elt, buffer, rbe, event);
4430 	case HIST_FIELD_FN_DIV:
4431 		return hist_field_div(hist_field, elt, buffer, rbe, event);
4432 	case HIST_FIELD_FN_MULT:
4433 		return hist_field_mult(hist_field, elt, buffer, rbe, event);
4434 	case HIST_FIELD_FN_DIV_POWER2:
4435 		return div_by_power_of_two(hist_field, elt, buffer, rbe, event);
4436 	case HIST_FIELD_FN_DIV_NOT_POWER2:
4437 		return div_by_not_power_of_two(hist_field, elt, buffer, rbe, event);
4438 	case HIST_FIELD_FN_DIV_MULT_SHIFT:
4439 		return div_by_mult_and_shift(hist_field, elt, buffer, rbe, event);
4440 	case HIST_FIELD_FN_EXECNAME:
4441 		return hist_field_execname(hist_field, elt, buffer, rbe, event);
4442 	case HIST_FIELD_FN_STACK:
4443 		return hist_field_stack(hist_field, elt, buffer, rbe, event);
4444 	default:
4445 		return 0;
4446 	}
4447 }
4448 
4449 /* Convert a var that points to common_pid.execname to a string */
4450 static void update_var_execname(struct hist_field *hist_field)
4451 {
4452 	hist_field->flags = HIST_FIELD_FL_STRING | HIST_FIELD_FL_VAR |
4453 		HIST_FIELD_FL_EXECNAME;
4454 	hist_field->size = MAX_FILTER_STR_VAL;
4455 	hist_field->is_signed = 0;
4456 
4457 	kfree_const(hist_field->type);
4458 	hist_field->type = "char[]";
4459 
4460 	hist_field->fn_num = HIST_FIELD_FN_EXECNAME;
4461 }
4462 
4463 static int create_var_field(struct hist_trigger_data *hist_data,
4464 			    unsigned int val_idx,
4465 			    struct trace_event_file *file,
4466 			    char *var_name, char *expr_str)
4467 {
4468 	struct trace_array *tr = hist_data->event_file->tr;
4469 	unsigned long flags = 0;
4470 	int ret;
4471 
4472 	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
4473 		return -EINVAL;
4474 
4475 	if (find_var(hist_data, file, var_name) && !hist_data->remove) {
4476 		hist_err(tr, HIST_ERR_DUPLICATE_VAR, errpos(var_name));
4477 		return -EINVAL;
4478 	}
4479 
4480 	flags |= HIST_FIELD_FL_VAR;
4481 	hist_data->n_vars++;
4482 	if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
4483 		return -EINVAL;
4484 
4485 	ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
4486 
4487 	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
4488 		update_var_execname(hist_data->fields[val_idx]);
4489 
4490 	if (!ret && hist_data->fields[val_idx]->flags &
4491 	    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
4492 		hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
4493 
4494 	return ret;
4495 }
4496 
4497 static int create_val_fields(struct hist_trigger_data *hist_data,
4498 			     struct trace_event_file *file)
4499 {
4500 	unsigned int i, j = 1, n_hitcount = 0;
4501 	char *fields_str, *field_str;
4502 	int ret;
4503 
4504 	ret = create_hitcount_val(hist_data);
4505 	if (ret)
4506 		goto out;
4507 
4508 	fields_str = hist_data->attrs->vals_str;
4509 	if (!fields_str)
4510 		goto out;
4511 
4512 	for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
4513 		     j < TRACING_MAP_VALS_MAX; i++) {
4514 		field_str = strsep(&fields_str, ",");
4515 		if (!field_str)
4516 			break;
4517 
4518 		if (strcmp(field_str, "hitcount") == 0) {
4519 			if (!n_hitcount++)
4520 				continue;
4521 		}
4522 
4523 		ret = create_val_field(hist_data, j++, file, field_str);
4524 		if (ret)
4525 			goto out;
4526 	}
4527 
4528 	if (fields_str && (strcmp(fields_str, "hitcount") != 0))
4529 		ret = -EINVAL;
4530  out:
4531 	/* There is only raw hitcount but nohitcount suppresses it. */
4532 	if (j == 1 && hist_data->attrs->no_hitcount) {
4533 		hist_err(hist_data->event_file->tr, HIST_ERR_NEED_NOHC_VAL, 0);
4534 		ret = -ENOENT;
4535 	}
4536 
4537 	return ret;
4538 }
4539 
4540 static int create_key_field(struct hist_trigger_data *hist_data,
4541 			    unsigned int key_idx,
4542 			    unsigned int key_offset,
4543 			    struct trace_event_file *file,
4544 			    char *field_str)
4545 {
4546 	struct trace_array *tr = hist_data->event_file->tr;
4547 	struct hist_field *hist_field = NULL;
4548 	unsigned long flags = 0;
4549 	unsigned int key_size;
4550 	int ret = 0, n_subexprs = 0;
4551 
4552 	if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
4553 		return -EINVAL;
4554 
4555 	flags |= HIST_FIELD_FL_KEY;
4556 
4557 	if (strcmp(field_str, "stacktrace") == 0) {
4558 		flags |= HIST_FIELD_FL_STACKTRACE;
4559 		key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
4560 		hist_field = create_hist_field(hist_data, NULL, flags, NULL);
4561 	} else {
4562 		hist_field = parse_expr(hist_data, file, field_str, flags,
4563 					NULL, &n_subexprs);
4564 		if (IS_ERR(hist_field)) {
4565 			ret = PTR_ERR(hist_field);
4566 			goto out;
4567 		}
4568 
4569 		if (field_has_hist_vars(hist_field, 0))	{
4570 			hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
4571 			destroy_hist_field(hist_field, 0);
4572 			ret = -EINVAL;
4573 			goto out;
4574 		}
4575 
4576 		key_size = hist_field->size;
4577 	}
4578 
4579 	hist_data->fields[key_idx] = hist_field;
4580 
4581 	key_size = ALIGN(key_size, sizeof(u64));
4582 	hist_data->fields[key_idx]->size = key_size;
4583 	hist_data->fields[key_idx]->offset = key_offset;
4584 
4585 	hist_data->key_size += key_size;
4586 
4587 	if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
4588 		ret = -EINVAL;
4589 		goto out;
4590 	}
4591 
4592 	hist_data->n_keys++;
4593 	hist_data->n_fields++;
4594 
4595 	if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
4596 		return -EINVAL;
4597 
4598 	ret = key_size;
4599  out:
4600 	return ret;
4601 }
4602 
4603 static int create_key_fields(struct hist_trigger_data *hist_data,
4604 			     struct trace_event_file *file)
4605 {
4606 	unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
4607 	char *fields_str, *field_str;
4608 	int ret = -EINVAL;
4609 
4610 	fields_str = hist_data->attrs->keys_str;
4611 	if (!fields_str)
4612 		goto out;
4613 
4614 	for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
4615 		field_str = strsep(&fields_str, ",");
4616 		if (!field_str)
4617 			break;
4618 		ret = create_key_field(hist_data, i, key_offset,
4619 				       file, field_str);
4620 		if (ret < 0)
4621 			goto out;
4622 		key_offset += ret;
4623 	}
4624 	if (fields_str) {
4625 		ret = -EINVAL;
4626 		goto out;
4627 	}
4628 	ret = 0;
4629  out:
4630 	return ret;
4631 }
4632 
4633 static int create_var_fields(struct hist_trigger_data *hist_data,
4634 			     struct trace_event_file *file)
4635 {
4636 	unsigned int i, j = hist_data->n_vals;
4637 	int ret = 0;
4638 
4639 	unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
4640 
4641 	for (i = 0; i < n_vars; i++) {
4642 		char *var_name = hist_data->attrs->var_defs.name[i];
4643 		char *expr = hist_data->attrs->var_defs.expr[i];
4644 
4645 		ret = create_var_field(hist_data, j++, file, var_name, expr);
4646 		if (ret)
4647 			goto out;
4648 	}
4649  out:
4650 	return ret;
4651 }
4652 
4653 static void free_var_defs(struct hist_trigger_data *hist_data)
4654 {
4655 	unsigned int i;
4656 
4657 	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
4658 		kfree(hist_data->attrs->var_defs.name[i]);
4659 		kfree(hist_data->attrs->var_defs.expr[i]);
4660 	}
4661 
4662 	hist_data->attrs->var_defs.n_vars = 0;
4663 }
4664 
4665 static int parse_var_defs(struct hist_trigger_data *hist_data)
4666 {
4667 	struct trace_array *tr = hist_data->event_file->tr;
4668 	char *s, *str, *var_name, *field_str;
4669 	unsigned int i, j, n_vars = 0;
4670 	int ret = 0;
4671 
4672 	for (i = 0; i < hist_data->attrs->n_assignments; i++) {
4673 		str = hist_data->attrs->assignment_str[i];
4674 		for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
4675 			field_str = strsep(&str, ",");
4676 			if (!field_str)
4677 				break;
4678 
4679 			var_name = strsep(&field_str, "=");
4680 			if (!var_name || !field_str) {
4681 				hist_err(tr, HIST_ERR_MALFORMED_ASSIGNMENT,
4682 					 errpos(var_name));
4683 				ret = -EINVAL;
4684 				goto free;
4685 			}
4686 
4687 			if (n_vars == TRACING_MAP_VARS_MAX) {
4688 				hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(var_name));
4689 				ret = -EINVAL;
4690 				goto free;
4691 			}
4692 
4693 			s = kstrdup(var_name, GFP_KERNEL);
4694 			if (!s) {
4695 				ret = -ENOMEM;
4696 				goto free;
4697 			}
4698 			hist_data->attrs->var_defs.name[n_vars] = s;
4699 
4700 			s = kstrdup(field_str, GFP_KERNEL);
4701 			if (!s) {
4702 				kfree(hist_data->attrs->var_defs.name[n_vars]);
4703 				hist_data->attrs->var_defs.name[n_vars] = NULL;
4704 				ret = -ENOMEM;
4705 				goto free;
4706 			}
4707 			hist_data->attrs->var_defs.expr[n_vars++] = s;
4708 
4709 			hist_data->attrs->var_defs.n_vars = n_vars;
4710 		}
4711 	}
4712 
4713 	return ret;
4714  free:
4715 	free_var_defs(hist_data);
4716 
4717 	return ret;
4718 }
4719 
4720 static int create_hist_fields(struct hist_trigger_data *hist_data,
4721 			      struct trace_event_file *file)
4722 {
4723 	int ret;
4724 
4725 	ret = parse_var_defs(hist_data);
4726 	if (ret)
4727 		return ret;
4728 
4729 	ret = create_val_fields(hist_data, file);
4730 	if (ret)
4731 		goto out;
4732 
4733 	ret = create_var_fields(hist_data, file);
4734 	if (ret)
4735 		goto out;
4736 
4737 	ret = create_key_fields(hist_data, file);
4738 
4739  out:
4740 	free_var_defs(hist_data);
4741 
4742 	return ret;
4743 }
4744 
4745 static int is_descending(struct trace_array *tr, const char *str)
4746 {
4747 	if (!str)
4748 		return 0;
4749 
4750 	if (strcmp(str, "descending") == 0)
4751 		return 1;
4752 
4753 	if (strcmp(str, "ascending") == 0)
4754 		return 0;
4755 
4756 	hist_err(tr, HIST_ERR_INVALID_SORT_MODIFIER, errpos((char *)str));
4757 
4758 	return -EINVAL;
4759 }
4760 
4761 static int create_sort_keys(struct hist_trigger_data *hist_data)
4762 {
4763 	struct trace_array *tr = hist_data->event_file->tr;
4764 	char *fields_str = hist_data->attrs->sort_key_str;
4765 	struct tracing_map_sort_key *sort_key;
4766 	int descending, ret = 0;
4767 	unsigned int i, j, k;
4768 
4769 	hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
4770 
4771 	if (!fields_str)
4772 		goto out;
4773 
4774 	for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
4775 		struct hist_field *hist_field;
4776 		char *field_str, *field_name;
4777 		const char *test_name;
4778 
4779 		sort_key = &hist_data->sort_keys[i];
4780 
4781 		field_str = strsep(&fields_str, ",");
4782 		if (!field_str)
4783 			break;
4784 
4785 		if (!*field_str) {
4786 			ret = -EINVAL;
4787 			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4788 			break;
4789 		}
4790 
4791 		if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
4792 			hist_err(tr, HIST_ERR_TOO_MANY_SORT_FIELDS, errpos("sort="));
4793 			ret = -EINVAL;
4794 			break;
4795 		}
4796 
4797 		field_name = strsep(&field_str, ".");
4798 		if (!field_name || !*field_name) {
4799 			ret = -EINVAL;
4800 			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
4801 			break;
4802 		}
4803 
4804 		if (strcmp(field_name, "hitcount") == 0) {
4805 			descending = is_descending(tr, field_str);
4806 			if (descending < 0) {
4807 				ret = descending;
4808 				break;
4809 			}
4810 			sort_key->descending = descending;
4811 			continue;
4812 		}
4813 
4814 		for (j = 1, k = 1; j < hist_data->n_fields; j++) {
4815 			unsigned int idx;
4816 
4817 			hist_field = hist_data->fields[j];
4818 			if (hist_field->flags & HIST_FIELD_FL_VAR)
4819 				continue;
4820 
4821 			idx = k++;
4822 
4823 			test_name = hist_field_name(hist_field, 0);
4824 
4825 			if (strcmp(field_name, test_name) == 0) {
4826 				sort_key->field_idx = idx;
4827 				descending = is_descending(tr, field_str);
4828 				if (descending < 0) {
4829 					ret = descending;
4830 					goto out;
4831 				}
4832 				sort_key->descending = descending;
4833 				break;
4834 			}
4835 		}
4836 		if (j == hist_data->n_fields) {
4837 			ret = -EINVAL;
4838 			hist_err(tr, HIST_ERR_INVALID_SORT_FIELD, errpos(field_name));
4839 			break;
4840 		}
4841 	}
4842 
4843 	hist_data->n_sort_keys = i;
4844  out:
4845 	return ret;
4846 }
4847 
4848 static void destroy_actions(struct hist_trigger_data *hist_data)
4849 {
4850 	unsigned int i;
4851 
4852 	for (i = 0; i < hist_data->n_actions; i++) {
4853 		struct action_data *data = hist_data->actions[i];
4854 
4855 		if (data->handler == HANDLER_ONMATCH)
4856 			onmatch_destroy(data);
4857 		else if (data->handler == HANDLER_ONMAX ||
4858 			 data->handler == HANDLER_ONCHANGE)
4859 			track_data_destroy(hist_data, data);
4860 		else
4861 			kfree(data);
4862 	}
4863 }
4864 
4865 static int parse_actions(struct hist_trigger_data *hist_data)
4866 {
4867 	struct trace_array *tr = hist_data->event_file->tr;
4868 	struct action_data *data;
4869 	unsigned int i;
4870 	int ret = 0;
4871 	char *str;
4872 	int len;
4873 
4874 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
4875 		enum handler_id hid = 0;
4876 		char *action_str;
4877 
4878 		str = hist_data->attrs->action_str[i];
4879 
4880 		if ((len = str_has_prefix(str, "onmatch(")))
4881 			hid = HANDLER_ONMATCH;
4882 		else if ((len = str_has_prefix(str, "onmax(")))
4883 			hid = HANDLER_ONMAX;
4884 		else if ((len = str_has_prefix(str, "onchange(")))
4885 			hid = HANDLER_ONCHANGE;
4886 
4887 		action_str = str + len;
4888 
4889 		switch (hid) {
4890 		case HANDLER_ONMATCH:
4891 			data = onmatch_parse(tr, action_str);
4892 			break;
4893 		case HANDLER_ONMAX:
4894 		case HANDLER_ONCHANGE:
4895 			data = track_data_parse(hist_data, action_str, hid);
4896 			break;
4897 		default:
4898 			data = ERR_PTR(-EINVAL);
4899 			break;
4900 		}
4901 
4902 		if (IS_ERR(data)) {
4903 			ret = PTR_ERR(data);
4904 			break;
4905 		}
4906 
4907 		hist_data->actions[hist_data->n_actions++] = data;
4908 	}
4909 
4910 	return ret;
4911 }
4912 
4913 static int create_actions(struct hist_trigger_data *hist_data)
4914 {
4915 	struct action_data *data;
4916 	unsigned int i;
4917 	int ret = 0;
4918 
4919 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
4920 		data = hist_data->actions[i];
4921 
4922 		if (data->handler == HANDLER_ONMATCH) {
4923 			ret = onmatch_create(hist_data, data);
4924 			if (ret)
4925 				break;
4926 		} else if (data->handler == HANDLER_ONMAX ||
4927 			   data->handler == HANDLER_ONCHANGE) {
4928 			ret = track_data_create(hist_data, data);
4929 			if (ret)
4930 				break;
4931 		} else {
4932 			ret = -EINVAL;
4933 			break;
4934 		}
4935 	}
4936 
4937 	return ret;
4938 }
4939 
4940 static void print_actions(struct seq_file *m,
4941 			  struct hist_trigger_data *hist_data,
4942 			  struct tracing_map_elt *elt)
4943 {
4944 	unsigned int i;
4945 
4946 	for (i = 0; i < hist_data->n_actions; i++) {
4947 		struct action_data *data = hist_data->actions[i];
4948 
4949 		if (data->action == ACTION_SNAPSHOT)
4950 			continue;
4951 
4952 		if (data->handler == HANDLER_ONMAX ||
4953 		    data->handler == HANDLER_ONCHANGE)
4954 			track_data_print(m, hist_data, elt, data);
4955 	}
4956 }
4957 
4958 static void print_action_spec(struct seq_file *m,
4959 			      struct hist_trigger_data *hist_data,
4960 			      struct action_data *data)
4961 {
4962 	unsigned int i;
4963 
4964 	if (data->action == ACTION_SAVE) {
4965 		for (i = 0; i < hist_data->n_save_vars; i++) {
4966 			seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
4967 			if (i < hist_data->n_save_vars - 1)
4968 				seq_puts(m, ",");
4969 		}
4970 	} else if (data->action == ACTION_TRACE) {
4971 		if (data->use_trace_keyword)
4972 			seq_printf(m, "%s", data->synth_event_name);
4973 		for (i = 0; i < data->n_params; i++) {
4974 			if (i || data->use_trace_keyword)
4975 				seq_puts(m, ",");
4976 			seq_printf(m, "%s", data->params[i]);
4977 		}
4978 	}
4979 }
4980 
4981 static void print_track_data_spec(struct seq_file *m,
4982 				  struct hist_trigger_data *hist_data,
4983 				  struct action_data *data)
4984 {
4985 	if (data->handler == HANDLER_ONMAX)
4986 		seq_puts(m, ":onmax(");
4987 	else if (data->handler == HANDLER_ONCHANGE)
4988 		seq_puts(m, ":onchange(");
4989 	seq_printf(m, "%s", data->track_data.var_str);
4990 	seq_printf(m, ").%s(", data->action_name);
4991 
4992 	print_action_spec(m, hist_data, data);
4993 
4994 	seq_puts(m, ")");
4995 }
4996 
4997 static void print_onmatch_spec(struct seq_file *m,
4998 			       struct hist_trigger_data *hist_data,
4999 			       struct action_data *data)
5000 {
5001 	seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
5002 		   data->match_data.event);
5003 
5004 	seq_printf(m, "%s(", data->action_name);
5005 
5006 	print_action_spec(m, hist_data, data);
5007 
5008 	seq_puts(m, ")");
5009 }
5010 
5011 static bool actions_match(struct hist_trigger_data *hist_data,
5012 			  struct hist_trigger_data *hist_data_test)
5013 {
5014 	unsigned int i, j;
5015 
5016 	if (hist_data->n_actions != hist_data_test->n_actions)
5017 		return false;
5018 
5019 	for (i = 0; i < hist_data->n_actions; i++) {
5020 		struct action_data *data = hist_data->actions[i];
5021 		struct action_data *data_test = hist_data_test->actions[i];
5022 		char *action_name, *action_name_test;
5023 
5024 		if (data->handler != data_test->handler)
5025 			return false;
5026 		if (data->action != data_test->action)
5027 			return false;
5028 
5029 		if (data->n_params != data_test->n_params)
5030 			return false;
5031 
5032 		for (j = 0; j < data->n_params; j++) {
5033 			if (strcmp(data->params[j], data_test->params[j]) != 0)
5034 				return false;
5035 		}
5036 
5037 		if (data->use_trace_keyword)
5038 			action_name = data->synth_event_name;
5039 		else
5040 			action_name = data->action_name;
5041 
5042 		if (data_test->use_trace_keyword)
5043 			action_name_test = data_test->synth_event_name;
5044 		else
5045 			action_name_test = data_test->action_name;
5046 
5047 		if (strcmp(action_name, action_name_test) != 0)
5048 			return false;
5049 
5050 		if (data->handler == HANDLER_ONMATCH) {
5051 			if (strcmp(data->match_data.event_system,
5052 				   data_test->match_data.event_system) != 0)
5053 				return false;
5054 			if (strcmp(data->match_data.event,
5055 				   data_test->match_data.event) != 0)
5056 				return false;
5057 		} else if (data->handler == HANDLER_ONMAX ||
5058 			   data->handler == HANDLER_ONCHANGE) {
5059 			if (strcmp(data->track_data.var_str,
5060 				   data_test->track_data.var_str) != 0)
5061 				return false;
5062 		}
5063 	}
5064 
5065 	return true;
5066 }
5067 
5068 
5069 static void print_actions_spec(struct seq_file *m,
5070 			       struct hist_trigger_data *hist_data)
5071 {
5072 	unsigned int i;
5073 
5074 	for (i = 0; i < hist_data->n_actions; i++) {
5075 		struct action_data *data = hist_data->actions[i];
5076 
5077 		if (data->handler == HANDLER_ONMATCH)
5078 			print_onmatch_spec(m, hist_data, data);
5079 		else if (data->handler == HANDLER_ONMAX ||
5080 			 data->handler == HANDLER_ONCHANGE)
5081 			print_track_data_spec(m, hist_data, data);
5082 	}
5083 }
5084 
5085 static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
5086 {
5087 	unsigned int i;
5088 
5089 	for (i = 0; i < hist_data->n_field_var_hists; i++) {
5090 		kfree(hist_data->field_var_hists[i]->cmd);
5091 		kfree(hist_data->field_var_hists[i]);
5092 	}
5093 }
5094 
5095 static void destroy_hist_data(struct hist_trigger_data *hist_data)
5096 {
5097 	if (!hist_data)
5098 		return;
5099 
5100 	destroy_hist_trigger_attrs(hist_data->attrs);
5101 	destroy_hist_fields(hist_data);
5102 	tracing_map_destroy(hist_data->map);
5103 
5104 	destroy_actions(hist_data);
5105 	destroy_field_vars(hist_data);
5106 	destroy_field_var_hists(hist_data);
5107 
5108 	kfree(hist_data);
5109 }
5110 
5111 static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
5112 {
5113 	struct tracing_map *map = hist_data->map;
5114 	struct ftrace_event_field *field;
5115 	struct hist_field *hist_field;
5116 	int i, idx = 0;
5117 
5118 	for_each_hist_field(i, hist_data) {
5119 		hist_field = hist_data->fields[i];
5120 		if (hist_field->flags & HIST_FIELD_FL_KEY) {
5121 			tracing_map_cmp_fn_t cmp_fn;
5122 
5123 			field = hist_field->field;
5124 
5125 			if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
5126 				cmp_fn = tracing_map_cmp_none;
5127 			else if (!field || hist_field->flags & HIST_FIELD_FL_CPU)
5128 				cmp_fn = tracing_map_cmp_num(hist_field->size,
5129 							     hist_field->is_signed);
5130 			else if (is_string_field(field))
5131 				cmp_fn = tracing_map_cmp_string;
5132 			else
5133 				cmp_fn = tracing_map_cmp_num(field->size,
5134 							     field->is_signed);
5135 			idx = tracing_map_add_key_field(map,
5136 							hist_field->offset,
5137 							cmp_fn);
5138 		} else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
5139 			idx = tracing_map_add_sum_field(map);
5140 
5141 		if (idx < 0)
5142 			return idx;
5143 
5144 		if (hist_field->flags & HIST_FIELD_FL_VAR) {
5145 			idx = tracing_map_add_var(map);
5146 			if (idx < 0)
5147 				return idx;
5148 			hist_field->var.idx = idx;
5149 			hist_field->var.hist_data = hist_data;
5150 		}
5151 	}
5152 
5153 	return 0;
5154 }
5155 
5156 static struct hist_trigger_data *
5157 create_hist_data(unsigned int map_bits,
5158 		 struct hist_trigger_attrs *attrs,
5159 		 struct trace_event_file *file,
5160 		 bool remove)
5161 {
5162 	const struct tracing_map_ops *map_ops = NULL;
5163 	struct hist_trigger_data *hist_data;
5164 	int ret = 0;
5165 
5166 	hist_data = kzalloc_obj(*hist_data);
5167 	if (!hist_data)
5168 		return ERR_PTR(-ENOMEM);
5169 
5170 	hist_data->attrs = attrs;
5171 	hist_data->remove = remove;
5172 	hist_data->event_file = file;
5173 
5174 	ret = parse_actions(hist_data);
5175 	if (ret)
5176 		goto free;
5177 
5178 	ret = create_hist_fields(hist_data, file);
5179 	if (ret)
5180 		goto free;
5181 
5182 	ret = create_sort_keys(hist_data);
5183 	if (ret)
5184 		goto free;
5185 
5186 	map_ops = &hist_trigger_elt_data_ops;
5187 
5188 	hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
5189 					    map_ops, hist_data);
5190 	if (IS_ERR(hist_data->map)) {
5191 		ret = PTR_ERR(hist_data->map);
5192 		hist_data->map = NULL;
5193 		goto free;
5194 	}
5195 
5196 	ret = create_tracing_map_fields(hist_data);
5197 	if (ret)
5198 		goto free;
5199  out:
5200 	return hist_data;
5201  free:
5202 	hist_data->attrs = NULL;
5203 
5204 	destroy_hist_data(hist_data);
5205 
5206 	hist_data = ERR_PTR(ret);
5207 
5208 	goto out;
5209 }
5210 
5211 static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
5212 				    struct tracing_map_elt *elt,
5213 				    struct trace_buffer *buffer, void *rec,
5214 				    struct ring_buffer_event *rbe,
5215 				    u64 *var_ref_vals)
5216 {
5217 	struct hist_elt_data *elt_data;
5218 	struct hist_field *hist_field;
5219 	unsigned int i, var_idx;
5220 	u64 hist_val;
5221 
5222 	elt_data = elt->private_data;
5223 	elt_data->var_ref_vals = var_ref_vals;
5224 
5225 	for_each_hist_val_field(i, hist_data) {
5226 		hist_field = hist_data->fields[i];
5227 		hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
5228 		if (hist_field->flags & HIST_FIELD_FL_VAR) {
5229 			var_idx = hist_field->var.idx;
5230 
5231 			if (hist_field->flags &
5232 			    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE)) {
5233 				unsigned int str_start, var_str_idx, idx;
5234 				char *str, *val_str;
5235 				unsigned int size;
5236 
5237 				str_start = hist_data->n_field_var_str +
5238 					hist_data->n_save_var_str;
5239 				var_str_idx = hist_field->var_str_idx;
5240 				idx = str_start + var_str_idx;
5241 
5242 				str = elt_data->field_var_str[idx];
5243 				val_str = (char *)(uintptr_t)hist_val;
5244 
5245 				if (hist_field->flags & HIST_FIELD_FL_STRING) {
5246 					size = min(hist_field->size, STR_VAR_LEN_MAX);
5247 					strscpy(str, val_str, size);
5248 				} else {
5249 					char *stack_start = str + sizeof(unsigned long);
5250 					int e;
5251 
5252 					e = stack_trace_save((void *)stack_start,
5253 							     HIST_STACKTRACE_DEPTH,
5254 							     HIST_STACKTRACE_SKIP);
5255 					if (e < HIST_STACKTRACE_DEPTH - 1)
5256 						((unsigned long *)stack_start)[e] = 0;
5257 					*((unsigned long *)str) = e;
5258 				}
5259 				hist_val = (u64)(uintptr_t)str;
5260 			}
5261 			tracing_map_set_var(elt, var_idx, hist_val);
5262 			continue;
5263 		}
5264 		tracing_map_update_sum(elt, i, hist_val);
5265 	}
5266 
5267 	for_each_hist_key_field(i, hist_data) {
5268 		hist_field = hist_data->fields[i];
5269 		if (hist_field->flags & HIST_FIELD_FL_VAR) {
5270 			hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
5271 			var_idx = hist_field->var.idx;
5272 			tracing_map_set_var(elt, var_idx, hist_val);
5273 		}
5274 	}
5275 
5276 	update_field_vars(hist_data, elt, buffer, rbe, rec);
5277 }
5278 
5279 static inline void add_to_key(char *compound_key, void *key,
5280 			      struct hist_field *key_field, void *rec)
5281 {
5282 	size_t size = key_field->size;
5283 
5284 	if (key_field->flags & HIST_FIELD_FL_STRING) {
5285 
5286 		if (key_field->flags & HIST_FIELD_FL_COMM) {
5287 			size = strlen((char *)key);
5288 		} else {
5289 			struct ftrace_event_field *field;
5290 
5291 			field = key_field->field;
5292 			if (field->filter_type == FILTER_DYN_STRING ||
5293 			    field->filter_type == FILTER_RDYN_STRING)
5294 				size = *(u32 *)(rec + field->offset) >> 16;
5295 			else if (field->filter_type == FILTER_STATIC_STRING)
5296 				size = field->size;
5297 		}
5298 
5299 		/* ensure NULL-termination */
5300 		if (size > key_field->size - 1)
5301 			size = key_field->size - 1;
5302 	}
5303 	memcpy(compound_key + key_field->offset, key, size);
5304 }
5305 
5306 static void
5307 hist_trigger_actions(struct hist_trigger_data *hist_data,
5308 		     struct tracing_map_elt *elt,
5309 		     struct trace_buffer *buffer, void *rec,
5310 		     struct ring_buffer_event *rbe, void *key,
5311 		     u64 *var_ref_vals)
5312 {
5313 	struct action_data *data;
5314 	unsigned int i;
5315 
5316 	for (i = 0; i < hist_data->n_actions; i++) {
5317 		data = hist_data->actions[i];
5318 		data->fn(hist_data, elt, buffer, rec, rbe, key, data, var_ref_vals);
5319 	}
5320 }
5321 
5322 /*
5323  * The hist_pad structure is used to save information to create
5324  * a histogram from the histogram trigger. It's too big to store
5325  * on the stack, so when the histogram trigger is initialized
5326  * a percpu array of 4 hist_pad structures is allocated.
5327  * This will cover every context from normal, softirq, irq and NMI
5328  * in the very unlikely event that a trigger happens at each of
5329  * these contexts and interrupts a currently active trigger.
5330  */
5331 struct hist_pad {
5332 	unsigned long		entries[HIST_STACKTRACE_DEPTH];
5333 	u64			var_ref_vals[TRACING_MAP_VARS_MAX];
5334 	char			compound_key[HIST_KEY_SIZE_MAX];
5335 };
5336 
5337 static struct hist_pad __percpu *hist_pads;
5338 static DEFINE_PER_CPU(int, hist_pad_cnt);
5339 static refcount_t hist_pad_ref;
5340 
5341 /* One hist_pad for every context (normal, softirq, irq, NMI) */
5342 #define MAX_HIST_CNT 4
5343 
5344 static int alloc_hist_pad(void)
5345 {
5346 	lockdep_assert_held(&event_mutex);
5347 
5348 	if (refcount_read(&hist_pad_ref)) {
5349 		refcount_inc(&hist_pad_ref);
5350 		return 0;
5351 	}
5352 
5353 	hist_pads = __alloc_percpu(sizeof(struct hist_pad) * MAX_HIST_CNT,
5354 				   __alignof__(struct hist_pad));
5355 	if (!hist_pads)
5356 		return -ENOMEM;
5357 
5358 	refcount_set(&hist_pad_ref, 1);
5359 	return 0;
5360 }
5361 
5362 static void free_hist_pad(void)
5363 {
5364 	lockdep_assert_held(&event_mutex);
5365 
5366 	if (!refcount_dec_and_test(&hist_pad_ref))
5367 		return;
5368 
5369 	free_percpu(hist_pads);
5370 	hist_pads = NULL;
5371 }
5372 
5373 static struct hist_pad *get_hist_pad(void)
5374 {
5375 	struct hist_pad *hist_pad;
5376 	int cnt;
5377 
5378 	if (WARN_ON_ONCE(!hist_pads))
5379 		return NULL;
5380 
5381 	preempt_disable();
5382 
5383 	hist_pad = per_cpu_ptr(hist_pads, smp_processor_id());
5384 
5385 	if (this_cpu_read(hist_pad_cnt) == MAX_HIST_CNT) {
5386 		preempt_enable();
5387 		return NULL;
5388 	}
5389 
5390 	cnt = this_cpu_inc_return(hist_pad_cnt) - 1;
5391 
5392 	return &hist_pad[cnt];
5393 }
5394 
5395 static void put_hist_pad(void)
5396 {
5397 	this_cpu_dec(hist_pad_cnt);
5398 	preempt_enable();
5399 }
5400 
5401 static void event_hist_trigger(struct event_trigger_data *data,
5402 			       struct trace_buffer *buffer, void *rec,
5403 			       struct ring_buffer_event *rbe)
5404 {
5405 	struct hist_trigger_data *hist_data = data->private_data;
5406 	bool use_compound_key = (hist_data->n_keys > 1);
5407 	struct tracing_map_elt *elt = NULL;
5408 	struct hist_field *key_field;
5409 	struct hist_pad *hist_pad;
5410 	u64 field_contents;
5411 	void *key = NULL;
5412 	unsigned int i;
5413 
5414 	if (unlikely(!rbe))
5415 		return;
5416 
5417 	hist_pad = get_hist_pad();
5418 	if (!hist_pad)
5419 		return;
5420 
5421 	memset(hist_pad->compound_key, 0, hist_data->key_size);
5422 
5423 	for_each_hist_key_field(i, hist_data) {
5424 		key_field = hist_data->fields[i];
5425 
5426 		if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5427 			unsigned long *entries = hist_pad->entries;
5428 
5429 			memset(entries, 0, HIST_STACKTRACE_SIZE);
5430 			if (key_field->field) {
5431 				unsigned long *stack, n_entries;
5432 
5433 				field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
5434 				stack = (unsigned long *)(long)field_contents;
5435 				n_entries = *stack;
5436 				memcpy(entries, ++stack, n_entries * sizeof(unsigned long));
5437 			} else {
5438 				stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
5439 						 HIST_STACKTRACE_SKIP);
5440 			}
5441 			key = entries;
5442 		} else {
5443 			field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
5444 			if (key_field->flags & HIST_FIELD_FL_STRING) {
5445 				key = (void *)(unsigned long)field_contents;
5446 				use_compound_key = true;
5447 			} else
5448 				key = (void *)&field_contents;
5449 		}
5450 
5451 		if (use_compound_key)
5452 			add_to_key(hist_pad->compound_key, key, key_field, rec);
5453 	}
5454 
5455 	if (use_compound_key)
5456 		key = hist_pad->compound_key;
5457 
5458 	if (hist_data->n_var_refs &&
5459 	    !resolve_var_refs(hist_data, key, hist_pad->var_ref_vals, false))
5460 		goto out;
5461 
5462 	elt = tracing_map_insert(hist_data->map, key);
5463 	if (!elt)
5464 		goto out;
5465 
5466 	hist_trigger_elt_update(hist_data, elt, buffer, rec, rbe, hist_pad->var_ref_vals);
5467 
5468 	if (resolve_var_refs(hist_data, key, hist_pad->var_ref_vals, true)) {
5469 		hist_trigger_actions(hist_data, elt, buffer, rec, rbe,
5470 				     key, hist_pad->var_ref_vals);
5471 	}
5472 
5473 	hist_poll_wakeup();
5474 
5475  out:
5476 	put_hist_pad();
5477 }
5478 
5479 static void hist_trigger_stacktrace_print(struct seq_file *m,
5480 					  unsigned long *stacktrace_entries,
5481 					  unsigned int max_entries)
5482 {
5483 	unsigned int spaces = 8;
5484 	unsigned int i;
5485 
5486 	for (i = 0; i < max_entries; i++) {
5487 		if (!stacktrace_entries[i])
5488 			return;
5489 
5490 		seq_printf(m, "%*c", 1 + spaces, ' ');
5491 		seq_printf(m, "%pS\n", (void*)stacktrace_entries[i]);
5492 	}
5493 }
5494 
5495 static void hist_trigger_print_key(struct seq_file *m,
5496 				   struct hist_trigger_data *hist_data,
5497 				   void *key,
5498 				   struct tracing_map_elt *elt)
5499 {
5500 	struct hist_field *key_field;
5501 	bool multiline = false;
5502 	const char *field_name;
5503 	unsigned int i;
5504 	u64 uval;
5505 
5506 	seq_puts(m, "{ ");
5507 
5508 	for_each_hist_key_field(i, hist_data) {
5509 		key_field = hist_data->fields[i];
5510 
5511 		if (i > hist_data->n_vals)
5512 			seq_puts(m, ", ");
5513 
5514 		field_name = hist_field_name(key_field, 0);
5515 
5516 		if (key_field->flags & HIST_FIELD_FL_HEX) {
5517 			uval = *(u64 *)(key + key_field->offset);
5518 			seq_printf(m, "%s: %llx", field_name, uval);
5519 		} else if (key_field->flags & HIST_FIELD_FL_SYM) {
5520 			uval = *(u64 *)(key + key_field->offset);
5521 			seq_printf(m, "%s: [%llx] %-45ps", field_name,
5522 				   uval, (void *)(uintptr_t)uval);
5523 		} else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
5524 			uval = *(u64 *)(key + key_field->offset);
5525 			seq_printf(m, "%s: [%llx] %-55pS", field_name,
5526 				   uval, (void *)(uintptr_t)uval);
5527 		} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
5528 			struct hist_elt_data *elt_data = elt->private_data;
5529 			char *comm;
5530 
5531 			if (WARN_ON_ONCE(!elt_data))
5532 				return;
5533 
5534 			comm = elt_data->comm;
5535 
5536 			uval = *(u64 *)(key + key_field->offset);
5537 			seq_printf(m, "%s: %-16s[%10llu]", field_name,
5538 				   comm, uval);
5539 		} else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
5540 			const char *syscall_name;
5541 
5542 			uval = *(u64 *)(key + key_field->offset);
5543 			syscall_name = get_syscall_name(uval);
5544 			if (!syscall_name)
5545 				syscall_name = "unknown_syscall";
5546 
5547 			seq_printf(m, "%s: %-30s[%3llu]", field_name,
5548 				   syscall_name, uval);
5549 		} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
5550 			if (key_field->field)
5551 				seq_printf(m, "%s.stacktrace", key_field->field->name);
5552 			else
5553 				seq_puts(m, "common_stacktrace:\n");
5554 			hist_trigger_stacktrace_print(m,
5555 						      key + key_field->offset,
5556 						      HIST_STACKTRACE_DEPTH);
5557 			multiline = true;
5558 		} else if (key_field->flags & HIST_FIELD_FL_LOG2) {
5559 			seq_printf(m, "%s: ~ 2^%-2llu", field_name,
5560 				   *(u64 *)(key + key_field->offset));
5561 		} else if (key_field->flags & HIST_FIELD_FL_BUCKET) {
5562 			unsigned long buckets = key_field->buckets;
5563 			uval = *(u64 *)(key + key_field->offset);
5564 			seq_printf(m, "%s: ~ %llu-%llu", field_name,
5565 				   uval, uval + buckets -1);
5566 		} else if (key_field->flags & HIST_FIELD_FL_STRING) {
5567 			seq_printf(m, "%s: %-50s", field_name,
5568 				   (char *)(key + key_field->offset));
5569 		} else {
5570 			uval = *(u64 *)(key + key_field->offset);
5571 			seq_printf(m, "%s: %10llu", field_name, uval);
5572 		}
5573 	}
5574 
5575 	if (!multiline)
5576 		seq_puts(m, " ");
5577 
5578 	seq_puts(m, "}");
5579 }
5580 
5581 /* Get the 100 times of the percentage of @val in @total */
5582 static inline unsigned int __get_percentage(u64 val, u64 total)
5583 {
5584 	if (!total)
5585 		goto div0;
5586 
5587 	if (val < (U64_MAX / 10000))
5588 		return (unsigned int)div64_ul(val * 10000, total);
5589 
5590 	total = div64_u64(total, 10000);
5591 	if (!total)
5592 		goto div0;
5593 
5594 	return (unsigned int)div64_ul(val, total);
5595 div0:
5596 	return val ? UINT_MAX : 0;
5597 }
5598 
5599 #define BAR_CHAR '#'
5600 
5601 static inline const char *__fill_bar_str(char *buf, int size, u64 val, u64 max)
5602 {
5603 	unsigned int len = __get_percentage(val, max);
5604 	int i;
5605 
5606 	if (len == UINT_MAX) {
5607 		snprintf(buf, size, "[ERROR]");
5608 		return buf;
5609 	}
5610 
5611 	len = len * size / 10000;
5612 	for (i = 0; i < len && i < size; i++)
5613 		buf[i] = BAR_CHAR;
5614 	while (i < size)
5615 		buf[i++] = ' ';
5616 	buf[size] = '\0';
5617 
5618 	return buf;
5619 }
5620 
5621 struct hist_val_stat {
5622 	u64 max;
5623 	u64 total;
5624 };
5625 
5626 static void hist_trigger_print_val(struct seq_file *m, unsigned int idx,
5627 				   const char *field_name, unsigned long flags,
5628 				   struct hist_val_stat *stats,
5629 				   struct tracing_map_elt *elt)
5630 {
5631 	u64 val = tracing_map_read_sum(elt, idx);
5632 	unsigned int pc;
5633 	char bar[21];
5634 
5635 	if (flags & HIST_FIELD_FL_PERCENT) {
5636 		pc = __get_percentage(val, stats[idx].total);
5637 		if (pc == UINT_MAX)
5638 			seq_printf(m, " %s (%%):[ERROR]", field_name);
5639 		else
5640 			seq_printf(m, " %s (%%): %3u.%02u", field_name,
5641 					pc / 100, pc % 100);
5642 	} else if (flags & HIST_FIELD_FL_GRAPH) {
5643 		seq_printf(m, " %s: %20s", field_name,
5644 			   __fill_bar_str(bar, 20, val, stats[idx].max));
5645 	} else if (flags & HIST_FIELD_FL_HEX) {
5646 		seq_printf(m, " %s: %10llx", field_name, val);
5647 	} else {
5648 		seq_printf(m, " %s: %10llu", field_name, val);
5649 	}
5650 }
5651 
5652 static void hist_trigger_entry_print(struct seq_file *m,
5653 				     struct hist_trigger_data *hist_data,
5654 				     struct hist_val_stat *stats,
5655 				     void *key,
5656 				     struct tracing_map_elt *elt)
5657 {
5658 	const char *field_name;
5659 	unsigned int i = HITCOUNT_IDX;
5660 	unsigned long flags;
5661 
5662 	hist_trigger_print_key(m, hist_data, key, elt);
5663 
5664 	/* At first, show the raw hitcount if !nohitcount */
5665 	if (!hist_data->attrs->no_hitcount)
5666 		hist_trigger_print_val(m, i, "hitcount", 0, stats, elt);
5667 
5668 	for (i = 1; i < hist_data->n_vals; i++) {
5669 		field_name = hist_field_name(hist_data->fields[i], 0);
5670 		flags = hist_data->fields[i]->flags;
5671 		if (flags & HIST_FIELD_FL_VAR || flags & HIST_FIELD_FL_EXPR)
5672 			continue;
5673 
5674 		seq_puts(m, " ");
5675 		hist_trigger_print_val(m, i, field_name, flags, stats, elt);
5676 	}
5677 
5678 	print_actions(m, hist_data, elt);
5679 
5680 	seq_puts(m, "\n");
5681 }
5682 
5683 static int print_entries(struct seq_file *m,
5684 			 struct hist_trigger_data *hist_data)
5685 {
5686 	struct tracing_map_sort_entry **sort_entries = NULL;
5687 	struct tracing_map *map = hist_data->map;
5688 	int i, j, n_entries, ret;
5689 	struct hist_val_stat *stats = NULL;
5690 	u64 val;
5691 
5692 	n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
5693 					     hist_data->n_sort_keys,
5694 					     &sort_entries);
5695 	if (n_entries < 0)
5696 		return n_entries;
5697 
5698 	ret = n_entries;
5699 
5700 	/* Calculate the max and the total for each field if needed. */
5701 	for (j = 0; j < hist_data->n_vals; j++) {
5702 		if (!(hist_data->fields[j]->flags &
5703 			(HIST_FIELD_FL_PERCENT | HIST_FIELD_FL_GRAPH)))
5704 			continue;
5705 		if (!stats) {
5706 			stats = kzalloc_objs(*stats, hist_data->n_vals);
5707 			if (!stats) {
5708 				ret = -ENOMEM;
5709 				goto out;
5710 			}
5711 		}
5712 		for (i = 0; i < n_entries; i++) {
5713 			val = tracing_map_read_sum(sort_entries[i]->elt, j);
5714 			stats[j].total += val;
5715 			if (stats[j].max < val)
5716 				stats[j].max = val;
5717 		}
5718 	}
5719 
5720 	for (i = 0; i < n_entries; i++)
5721 		hist_trigger_entry_print(m, hist_data, stats,
5722 					 sort_entries[i]->key,
5723 					 sort_entries[i]->elt);
5724 
5725 	kfree(stats);
5726 out:
5727 	tracing_map_destroy_sort_entries(sort_entries, n_entries);
5728 
5729 	return ret;
5730 }
5731 
5732 static void hist_trigger_show(struct seq_file *m,
5733 			      struct event_trigger_data *data, int n)
5734 {
5735 	struct hist_trigger_data *hist_data;
5736 	int n_entries;
5737 
5738 	if (n > 0)
5739 		seq_puts(m, "\n\n");
5740 
5741 	seq_puts(m, "# event histogram\n#\n# trigger info: ");
5742 	data->cmd_ops->print(m, data);
5743 	seq_puts(m, "#\n\n");
5744 
5745 	hist_data = data->private_data;
5746 	n_entries = print_entries(m, hist_data);
5747 	if (n_entries < 0)
5748 		n_entries = 0;
5749 
5750 	track_data_snapshot_print(m, hist_data);
5751 
5752 	seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
5753 		   (u64)atomic64_read(&hist_data->map->hits),
5754 		   n_entries, (u64)atomic64_read(&hist_data->map->drops));
5755 }
5756 
5757 struct hist_file_data {
5758 	struct file *file;
5759 	u64 last_read;
5760 	u64 last_act;
5761 };
5762 
5763 static u64 get_hist_hit_count(struct trace_event_file *event_file)
5764 {
5765 	struct hist_trigger_data *hist_data;
5766 	struct event_trigger_data *data;
5767 	u64 ret = 0;
5768 
5769 	list_for_each_entry(data, &event_file->triggers, list) {
5770 		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST) {
5771 			hist_data = data->private_data;
5772 			ret += atomic64_read(&hist_data->map->hits);
5773 		}
5774 	}
5775 	return ret;
5776 }
5777 
5778 static int hist_show(struct seq_file *m, void *v)
5779 {
5780 	struct hist_file_data *hist_file = m->private;
5781 	struct event_trigger_data *data;
5782 	struct trace_event_file *event_file;
5783 	int n = 0;
5784 
5785 	guard(mutex)(&event_mutex);
5786 
5787 	event_file = event_file_file(hist_file->file);
5788 	if (unlikely(!event_file))
5789 		return -ENODEV;
5790 
5791 	list_for_each_entry(data, &event_file->triggers, list) {
5792 		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
5793 			hist_trigger_show(m, data, n++);
5794 	}
5795 	hist_file->last_read = get_hist_hit_count(event_file);
5796 	/*
5797 	 * Update last_act too so that poll()/POLLPRI can wait for the next
5798 	 * event after any syscall on hist file.
5799 	 */
5800 	hist_file->last_act = hist_file->last_read;
5801 
5802 	return 0;
5803 }
5804 
5805 static __poll_t event_hist_poll(struct file *file, struct poll_table_struct *wait)
5806 {
5807 	struct trace_event_file *event_file;
5808 	struct seq_file *m = file->private_data;
5809 	struct hist_file_data *hist_file = m->private;
5810 	__poll_t ret = 0;
5811 	u64 cnt;
5812 
5813 	guard(mutex)(&event_mutex);
5814 
5815 	event_file = event_file_file(file);
5816 	if (!event_file)
5817 		return EPOLLERR;
5818 
5819 	hist_poll_wait(file, wait);
5820 
5821 	cnt = get_hist_hit_count(event_file);
5822 	if (hist_file->last_read != cnt)
5823 		ret |= EPOLLIN | EPOLLRDNORM;
5824 	if (hist_file->last_act != cnt) {
5825 		hist_file->last_act = cnt;
5826 		ret |= EPOLLPRI;
5827 	}
5828 
5829 	return ret;
5830 }
5831 
5832 static int event_hist_release(struct inode *inode, struct file *file)
5833 {
5834 	struct seq_file *m = file->private_data;
5835 	struct hist_file_data *hist_file = m->private;
5836 
5837 	kfree(hist_file);
5838 	return tracing_single_release_file_tr(inode, file);
5839 }
5840 
5841 static int event_hist_open(struct inode *inode, struct file *file)
5842 {
5843 	struct trace_event_file *event_file;
5844 	struct hist_file_data *hist_file;
5845 	int ret;
5846 
5847 	ret = tracing_open_file_tr(inode, file);
5848 	if (ret)
5849 		return ret;
5850 
5851 	guard(mutex)(&event_mutex);
5852 
5853 	event_file = event_file_file(file);
5854 	if (!event_file) {
5855 		ret = -ENODEV;
5856 		goto err;
5857 	}
5858 
5859 	hist_file = kzalloc_obj(*hist_file);
5860 	if (!hist_file) {
5861 		ret = -ENOMEM;
5862 		goto err;
5863 	}
5864 
5865 	hist_file->file = file;
5866 	hist_file->last_act = get_hist_hit_count(event_file);
5867 
5868 	ret = single_open(file, hist_show, hist_file);
5869 	if (ret) {
5870 		kfree(hist_file);
5871 		goto err;
5872 	}
5873 
5874 	return 0;
5875 err:
5876 	tracing_release_file_tr(inode, file);
5877 	return ret;
5878 }
5879 
5880 const struct file_operations event_hist_fops = {
5881 	.open = event_hist_open,
5882 	.read = seq_read,
5883 	.llseek = seq_lseek,
5884 	.release = event_hist_release,
5885 	.poll = event_hist_poll,
5886 };
5887 
5888 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
5889 
5890 #undef C
5891 #define C(a, b)		b
5892 
5893 static const char * const field_funcs[] = { FIELD_FUNCS };
5894 
5895 static void hist_field_debug_show_flags(struct seq_file *m,
5896 					unsigned long flags)
5897 {
5898 	seq_puts(m, "      flags:\n");
5899 
5900 	if (flags & HIST_FIELD_FL_KEY)
5901 		seq_puts(m, "        HIST_FIELD_FL_KEY\n");
5902 	else if (flags & HIST_FIELD_FL_HITCOUNT)
5903 		seq_puts(m, "        VAL: HIST_FIELD_FL_HITCOUNT\n");
5904 	else if (flags & HIST_FIELD_FL_VAR)
5905 		seq_puts(m, "        HIST_FIELD_FL_VAR\n");
5906 	else if (flags & HIST_FIELD_FL_VAR_REF)
5907 		seq_puts(m, "        HIST_FIELD_FL_VAR_REF\n");
5908 	else
5909 		seq_puts(m, "        VAL: normal u64 value\n");
5910 
5911 	if (flags & HIST_FIELD_FL_ALIAS)
5912 		seq_puts(m, "        HIST_FIELD_FL_ALIAS\n");
5913 	else if (flags & HIST_FIELD_FL_CONST)
5914 		seq_puts(m, "        HIST_FIELD_FL_CONST\n");
5915 }
5916 
5917 static int hist_field_debug_show(struct seq_file *m,
5918 				 struct hist_field *field, unsigned long flags)
5919 {
5920 	if ((field->flags & flags) != flags) {
5921 		seq_printf(m, "ERROR: bad flags - %lx\n", flags);
5922 		return -EINVAL;
5923 	}
5924 
5925 	hist_field_debug_show_flags(m, field->flags);
5926 	if (field->field)
5927 		seq_printf(m, "      ftrace_event_field name: %s\n",
5928 			   field->field->name);
5929 
5930 	if (field->flags & HIST_FIELD_FL_VAR) {
5931 		seq_printf(m, "      var.name: %s\n", field->var.name);
5932 		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5933 			   field->var.idx);
5934 	}
5935 
5936 	if (field->flags & HIST_FIELD_FL_CONST)
5937 		seq_printf(m, "      constant: %llu\n", field->constant);
5938 
5939 	if (field->flags & HIST_FIELD_FL_ALIAS)
5940 		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5941 			   field->var_ref_idx);
5942 
5943 	if (field->flags & HIST_FIELD_FL_VAR_REF) {
5944 		seq_printf(m, "      name: %s\n", field->name);
5945 		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5946 			   field->var.idx);
5947 		seq_printf(m, "      var.hist_data: %p\n", field->var.hist_data);
5948 		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
5949 			   field->var_ref_idx);
5950 		if (field->system)
5951 			seq_printf(m, "      system: %s\n", field->system);
5952 		if (field->event_name)
5953 			seq_printf(m, "      event_name: %s\n", field->event_name);
5954 	}
5955 
5956 	seq_printf(m, "      type: %s\n", field->type);
5957 	seq_printf(m, "      size: %u\n", field->size);
5958 	seq_printf(m, "      is_signed: %u\n", field->is_signed);
5959 	seq_printf(m, "      function: hist_field_%s()\n", field_funcs[field->fn_num]);
5960 
5961 	return 0;
5962 }
5963 
5964 static int field_var_debug_show(struct seq_file *m,
5965 				struct field_var *field_var, unsigned int i,
5966 				bool save_vars)
5967 {
5968 	const char *vars_name = save_vars ? "save_vars" : "field_vars";
5969 	struct hist_field *field;
5970 	int ret = 0;
5971 
5972 	seq_printf(m, "\n    hist_data->%s[%d]:\n", vars_name, i);
5973 
5974 	field = field_var->var;
5975 
5976 	seq_printf(m, "\n      %s[%d].var:\n", vars_name, i);
5977 
5978 	hist_field_debug_show_flags(m, field->flags);
5979 	seq_printf(m, "      var.name: %s\n", field->var.name);
5980 	seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
5981 		   field->var.idx);
5982 
5983 	field = field_var->val;
5984 
5985 	seq_printf(m, "\n      %s[%d].val:\n", vars_name, i);
5986 	if (field->field)
5987 		seq_printf(m, "      ftrace_event_field name: %s\n",
5988 			   field->field->name);
5989 	else {
5990 		ret = -EINVAL;
5991 		goto out;
5992 	}
5993 
5994 	seq_printf(m, "      type: %s\n", field->type);
5995 	seq_printf(m, "      size: %u\n", field->size);
5996 	seq_printf(m, "      is_signed: %u\n", field->is_signed);
5997 out:
5998 	return ret;
5999 }
6000 
6001 static int hist_action_debug_show(struct seq_file *m,
6002 				  struct action_data *data, int i)
6003 {
6004 	int ret = 0;
6005 
6006 	if (data->handler == HANDLER_ONMAX ||
6007 	    data->handler == HANDLER_ONCHANGE) {
6008 		seq_printf(m, "\n    hist_data->actions[%d].track_data.var_ref:\n", i);
6009 		ret = hist_field_debug_show(m, data->track_data.var_ref,
6010 					    HIST_FIELD_FL_VAR_REF);
6011 		if (ret)
6012 			goto out;
6013 
6014 		seq_printf(m, "\n    hist_data->actions[%d].track_data.track_var:\n", i);
6015 		ret = hist_field_debug_show(m, data->track_data.track_var,
6016 					    HIST_FIELD_FL_VAR);
6017 		if (ret)
6018 			goto out;
6019 	}
6020 
6021 	if (data->handler == HANDLER_ONMATCH) {
6022 		seq_printf(m, "\n    hist_data->actions[%d].match_data.event_system: %s\n",
6023 			   i, data->match_data.event_system);
6024 		seq_printf(m, "    hist_data->actions[%d].match_data.event: %s\n",
6025 			   i, data->match_data.event);
6026 	}
6027 out:
6028 	return ret;
6029 }
6030 
6031 static int hist_actions_debug_show(struct seq_file *m,
6032 				   struct hist_trigger_data *hist_data)
6033 {
6034 	int i, ret = 0;
6035 
6036 	if (hist_data->n_actions)
6037 		seq_puts(m, "\n  action tracking variables (for onmax()/onchange()/onmatch()):\n");
6038 
6039 	for (i = 0; i < hist_data->n_actions; i++) {
6040 		struct action_data *action = hist_data->actions[i];
6041 
6042 		ret = hist_action_debug_show(m, action, i);
6043 		if (ret)
6044 			goto out;
6045 	}
6046 
6047 	if (hist_data->n_save_vars)
6048 		seq_puts(m, "\n  save action variables (save() params):\n");
6049 
6050 	for (i = 0; i < hist_data->n_save_vars; i++) {
6051 		ret = field_var_debug_show(m, hist_data->save_vars[i], i, true);
6052 		if (ret)
6053 			goto out;
6054 	}
6055 out:
6056 	return ret;
6057 }
6058 
6059 static void hist_trigger_debug_show(struct seq_file *m,
6060 				    struct event_trigger_data *data, int n)
6061 {
6062 	struct hist_trigger_data *hist_data;
6063 	int i, ret;
6064 
6065 	if (n > 0)
6066 		seq_puts(m, "\n\n");
6067 
6068 	seq_puts(m, "# event histogram\n#\n# trigger info: ");
6069 	data->cmd_ops->print(m, data);
6070 	seq_puts(m, "#\n\n");
6071 
6072 	hist_data = data->private_data;
6073 
6074 	seq_printf(m, "hist_data: %p\n\n", hist_data);
6075 	seq_printf(m, "  n_vals: %u\n", hist_data->n_vals);
6076 	seq_printf(m, "  n_keys: %u\n", hist_data->n_keys);
6077 	seq_printf(m, "  n_fields: %u\n", hist_data->n_fields);
6078 
6079 	seq_puts(m, "\n  val fields:\n\n");
6080 
6081 	seq_puts(m, "    hist_data->fields[0]:\n");
6082 	ret = hist_field_debug_show(m, hist_data->fields[0],
6083 				    HIST_FIELD_FL_HITCOUNT);
6084 	if (ret)
6085 		return;
6086 
6087 	for (i = 1; i < hist_data->n_vals; i++) {
6088 		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
6089 		ret = hist_field_debug_show(m, hist_data->fields[i], 0);
6090 		if (ret)
6091 			return;
6092 	}
6093 
6094 	seq_puts(m, "\n  key fields:\n");
6095 
6096 	for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
6097 		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
6098 		ret = hist_field_debug_show(m, hist_data->fields[i],
6099 					    HIST_FIELD_FL_KEY);
6100 		if (ret)
6101 			return;
6102 	}
6103 
6104 	if (hist_data->n_var_refs)
6105 		seq_puts(m, "\n  variable reference fields:\n");
6106 
6107 	for (i = 0; i < hist_data->n_var_refs; i++) {
6108 		seq_printf(m, "\n    hist_data->var_refs[%d]:\n", i);
6109 		ret = hist_field_debug_show(m, hist_data->var_refs[i],
6110 					    HIST_FIELD_FL_VAR_REF);
6111 		if (ret)
6112 			return;
6113 	}
6114 
6115 	if (hist_data->n_field_vars)
6116 		seq_puts(m, "\n  field variables:\n");
6117 
6118 	for (i = 0; i < hist_data->n_field_vars; i++) {
6119 		ret = field_var_debug_show(m, hist_data->field_vars[i], i, false);
6120 		if (ret)
6121 			return;
6122 	}
6123 
6124 	ret = hist_actions_debug_show(m, hist_data);
6125 	if (ret)
6126 		return;
6127 }
6128 
6129 static int hist_debug_show(struct seq_file *m, void *v)
6130 {
6131 	struct event_trigger_data *data;
6132 	struct trace_event_file *event_file;
6133 	int n = 0;
6134 
6135 	guard(mutex)(&event_mutex);
6136 
6137 	event_file = event_file_file(m->private);
6138 	if (unlikely(!event_file))
6139 		return -ENODEV;
6140 
6141 	list_for_each_entry(data, &event_file->triggers, list) {
6142 		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
6143 			hist_trigger_debug_show(m, data, n++);
6144 	}
6145 	return 0;
6146 }
6147 
6148 static int event_hist_debug_open(struct inode *inode, struct file *file)
6149 {
6150 	int ret;
6151 
6152 	ret = tracing_open_file_tr(inode, file);
6153 	if (ret)
6154 		return ret;
6155 
6156 	ret = single_open(file, hist_debug_show, file);
6157 	if (ret)
6158 		tracing_release_file_tr(inode, file);
6159 	return ret;
6160 }
6161 
6162 const struct file_operations event_hist_debug_fops = {
6163 	.open = event_hist_debug_open,
6164 	.read = seq_read,
6165 	.llseek = seq_lseek,
6166 	.release = tracing_single_release_file_tr,
6167 };
6168 #endif
6169 
6170 static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
6171 {
6172 	const char *field_name = hist_field_name(hist_field, 0);
6173 
6174 	if (hist_field->var.name)
6175 		seq_printf(m, "%s=", hist_field->var.name);
6176 
6177 	if (hist_field->flags & HIST_FIELD_FL_CPU)
6178 		seq_puts(m, "common_cpu");
6179 	if (hist_field->flags & HIST_FIELD_FL_COMM)
6180 		seq_puts(m, "common_comm");
6181 	else if (hist_field->flags & HIST_FIELD_FL_CONST)
6182 		seq_printf(m, "%llu", hist_field->constant);
6183 	else if (field_name) {
6184 		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
6185 		    hist_field->flags & HIST_FIELD_FL_ALIAS)
6186 			if (!hist_field->system)
6187 				seq_putc(m, '$');
6188 		seq_printf(m, "%s", field_name);
6189 	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
6190 		seq_puts(m, "common_timestamp");
6191 
6192 	if (hist_field->flags) {
6193 		if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
6194 		    !(hist_field->flags & HIST_FIELD_FL_EXPR) &&
6195 		    !(hist_field->flags & HIST_FIELD_FL_STACKTRACE)) {
6196 			const char *flags = get_hist_field_flags(hist_field);
6197 
6198 			if (flags)
6199 				seq_printf(m, ".%s", flags);
6200 		}
6201 	}
6202 	if (hist_field->buckets)
6203 		seq_printf(m, "=%ld", hist_field->buckets);
6204 }
6205 
6206 static int event_hist_trigger_print(struct seq_file *m,
6207 				    struct event_trigger_data *data)
6208 {
6209 	struct hist_trigger_data *hist_data = data->private_data;
6210 	struct hist_field *field;
6211 	bool have_var = false;
6212 	bool show_val = false;
6213 	unsigned int i;
6214 
6215 	seq_puts(m, HIST_PREFIX);
6216 
6217 	if (data->name)
6218 		seq_printf(m, "%s:", data->name);
6219 
6220 	seq_puts(m, "keys=");
6221 
6222 	for_each_hist_key_field(i, hist_data) {
6223 		field = hist_data->fields[i];
6224 
6225 		if (i > hist_data->n_vals)
6226 			seq_puts(m, ",");
6227 
6228 		if (field->flags & HIST_FIELD_FL_STACKTRACE) {
6229 			if (field->field)
6230 				seq_printf(m, "%s.stacktrace", field->field->name);
6231 			else
6232 				seq_puts(m, "common_stacktrace");
6233 		} else
6234 			hist_field_print(m, field);
6235 	}
6236 
6237 	seq_puts(m, ":vals=");
6238 
6239 	for_each_hist_val_field(i, hist_data) {
6240 		field = hist_data->fields[i];
6241 		if (field->flags & HIST_FIELD_FL_VAR) {
6242 			have_var = true;
6243 			continue;
6244 		}
6245 
6246 		if (i == HITCOUNT_IDX) {
6247 			if (hist_data->attrs->no_hitcount)
6248 				continue;
6249 			seq_puts(m, "hitcount");
6250 		} else {
6251 			if (show_val)
6252 				seq_puts(m, ",");
6253 			hist_field_print(m, field);
6254 		}
6255 		show_val = true;
6256 	}
6257 
6258 	if (have_var) {
6259 		unsigned int n = 0;
6260 
6261 		seq_puts(m, ":");
6262 
6263 		for_each_hist_val_field(i, hist_data) {
6264 			field = hist_data->fields[i];
6265 
6266 			if (field->flags & HIST_FIELD_FL_VAR) {
6267 				if (n++)
6268 					seq_puts(m, ",");
6269 				hist_field_print(m, field);
6270 			}
6271 		}
6272 	}
6273 
6274 	seq_puts(m, ":sort=");
6275 
6276 	for (i = 0; i < hist_data->n_sort_keys; i++) {
6277 		struct tracing_map_sort_key *sort_key;
6278 		unsigned int idx, first_key_idx;
6279 
6280 		/* skip VAR vals */
6281 		first_key_idx = hist_data->n_vals - hist_data->n_vars;
6282 
6283 		sort_key = &hist_data->sort_keys[i];
6284 		idx = sort_key->field_idx;
6285 
6286 		if (WARN_ON(idx >= HIST_FIELDS_MAX))
6287 			return -EINVAL;
6288 
6289 		if (i > 0)
6290 			seq_puts(m, ",");
6291 
6292 		if (idx == HITCOUNT_IDX)
6293 			seq_puts(m, "hitcount");
6294 		else {
6295 			if (idx >= first_key_idx)
6296 				idx += hist_data->n_vars;
6297 			hist_field_print(m, hist_data->fields[idx]);
6298 		}
6299 
6300 		if (sort_key->descending)
6301 			seq_puts(m, ".descending");
6302 	}
6303 	seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
6304 	if (hist_data->enable_timestamps)
6305 		seq_printf(m, ":clock=%s", hist_data->attrs->clock);
6306 	if (hist_data->attrs->no_hitcount)
6307 		seq_puts(m, ":nohitcount");
6308 
6309 	print_actions_spec(m, hist_data);
6310 
6311 	if (data->filter_str)
6312 		seq_printf(m, " if %s", data->filter_str);
6313 
6314 	if (data->paused)
6315 		seq_puts(m, " [paused]");
6316 	else
6317 		seq_puts(m, " [active]");
6318 
6319 	seq_putc(m, '\n');
6320 
6321 	return 0;
6322 }
6323 
6324 static int event_hist_trigger_init(struct event_trigger_data *data)
6325 {
6326 	struct hist_trigger_data *hist_data = data->private_data;
6327 
6328 	if (alloc_hist_pad() < 0)
6329 		return -ENOMEM;
6330 
6331 	if (!data->ref && hist_data->attrs->name)
6332 		save_named_trigger(hist_data->attrs->name, data);
6333 
6334 	data->ref++;
6335 
6336 	return 0;
6337 }
6338 
6339 static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
6340 {
6341 	struct trace_event_file *file;
6342 	unsigned int i;
6343 	char *cmd;
6344 	int ret;
6345 
6346 	for (i = 0; i < hist_data->n_field_var_hists; i++) {
6347 		file = hist_data->field_var_hists[i]->hist_data->event_file;
6348 		cmd = hist_data->field_var_hists[i]->cmd;
6349 		ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
6350 					       "!hist", "hist", cmd);
6351 		WARN_ON_ONCE(ret < 0);
6352 	}
6353 }
6354 
6355 static void event_hist_trigger_free(struct event_trigger_data *data)
6356 {
6357 	struct hist_trigger_data *hist_data = data->private_data;
6358 
6359 	if (WARN_ON_ONCE(data->ref <= 0))
6360 		return;
6361 
6362 	data->ref--;
6363 	if (!data->ref) {
6364 		if (data->name)
6365 			del_named_trigger(data);
6366 
6367 		trigger_data_free(data);
6368 
6369 		tracepoint_synchronize_unregister();
6370 		remove_hist_vars(hist_data);
6371 
6372 		unregister_field_var_hists(hist_data);
6373 
6374 		destroy_hist_data(hist_data);
6375 	}
6376 	free_hist_pad();
6377 }
6378 
6379 static int event_hist_trigger_named_init(struct event_trigger_data *data)
6380 {
6381 	int ret;
6382 
6383 	ret = event_hist_trigger_init(data->named_data);
6384 	if (ret < 0) {
6385 		kfree(data->cmd_ops);
6386 		data->cmd_ops = &trigger_hist_cmd;
6387 		return ret;
6388 	}
6389 
6390 	data->ref++;
6391 
6392 	save_named_trigger(data->named_data->name, data);
6393 
6394 	return 0;
6395 }
6396 
6397 static void event_hist_trigger_named_free(struct event_trigger_data *data)
6398 {
6399 	if (WARN_ON_ONCE(data->ref <= 0))
6400 		return;
6401 
6402 	event_hist_trigger_free(data->named_data);
6403 
6404 	data->ref--;
6405 	if (!data->ref) {
6406 		struct event_command *cmd_ops = data->cmd_ops;
6407 
6408 		del_named_trigger(data);
6409 		trigger_data_free(data);
6410 		tracepoint_synchronize_unregister();
6411 		kfree(cmd_ops);
6412 	}
6413 }
6414 
6415 static void hist_clear(struct event_trigger_data *data)
6416 {
6417 	struct hist_trigger_data *hist_data = data->private_data;
6418 
6419 	if (data->name)
6420 		pause_named_trigger(data);
6421 
6422 	tracepoint_synchronize_unregister();
6423 
6424 	tracing_map_clear(hist_data->map);
6425 
6426 	if (data->name)
6427 		unpause_named_trigger(data);
6428 }
6429 
6430 static bool compatible_field(struct ftrace_event_field *field,
6431 			     struct ftrace_event_field *test_field)
6432 {
6433 	if (field == test_field)
6434 		return true;
6435 	if (field == NULL || test_field == NULL)
6436 		return false;
6437 	if (strcmp(field->name, test_field->name) != 0)
6438 		return false;
6439 	if (strcmp(field->type, test_field->type) != 0)
6440 		return false;
6441 	if (field->size != test_field->size)
6442 		return false;
6443 	if (field->is_signed != test_field->is_signed)
6444 		return false;
6445 
6446 	return true;
6447 }
6448 
6449 static bool hist_trigger_match(struct event_trigger_data *data,
6450 			       struct event_trigger_data *data_test,
6451 			       struct event_trigger_data *named_data,
6452 			       bool ignore_filter)
6453 {
6454 	struct tracing_map_sort_key *sort_key, *sort_key_test;
6455 	struct hist_trigger_data *hist_data, *hist_data_test;
6456 	struct hist_field *key_field, *key_field_test;
6457 	unsigned int i;
6458 
6459 	if (named_data && (named_data != data_test) &&
6460 	    (named_data != data_test->named_data))
6461 		return false;
6462 
6463 	if (!named_data && is_named_trigger(data_test))
6464 		return false;
6465 
6466 	hist_data = data->private_data;
6467 	hist_data_test = data_test->private_data;
6468 
6469 	if (hist_data->n_vals != hist_data_test->n_vals ||
6470 	    hist_data->n_fields != hist_data_test->n_fields ||
6471 	    hist_data->n_sort_keys != hist_data_test->n_sort_keys)
6472 		return false;
6473 
6474 	if (!ignore_filter) {
6475 		if ((data->filter_str && !data_test->filter_str) ||
6476 		   (!data->filter_str && data_test->filter_str))
6477 			return false;
6478 	}
6479 
6480 	for_each_hist_field(i, hist_data) {
6481 		key_field = hist_data->fields[i];
6482 		key_field_test = hist_data_test->fields[i];
6483 
6484 		if (key_field->flags != key_field_test->flags)
6485 			return false;
6486 		if (!compatible_field(key_field->field, key_field_test->field))
6487 			return false;
6488 		if (key_field->offset != key_field_test->offset)
6489 			return false;
6490 		if (key_field->size != key_field_test->size)
6491 			return false;
6492 		if (key_field->is_signed != key_field_test->is_signed)
6493 			return false;
6494 		if (!!key_field->var.name != !!key_field_test->var.name)
6495 			return false;
6496 		if (key_field->var.name &&
6497 		    strcmp(key_field->var.name, key_field_test->var.name) != 0)
6498 			return false;
6499 	}
6500 
6501 	for (i = 0; i < hist_data->n_sort_keys; i++) {
6502 		sort_key = &hist_data->sort_keys[i];
6503 		sort_key_test = &hist_data_test->sort_keys[i];
6504 
6505 		if (sort_key->field_idx != sort_key_test->field_idx ||
6506 		    sort_key->descending != sort_key_test->descending)
6507 			return false;
6508 	}
6509 
6510 	if (!ignore_filter && data->filter_str &&
6511 	    (strcmp(data->filter_str, data_test->filter_str) != 0))
6512 		return false;
6513 
6514 	if (!actions_match(hist_data, hist_data_test))
6515 		return false;
6516 
6517 	return true;
6518 }
6519 
6520 static bool existing_hist_update_only(char *glob,
6521 				      struct event_trigger_data *data,
6522 				      struct trace_event_file *file)
6523 {
6524 	struct hist_trigger_data *hist_data = data->private_data;
6525 	struct event_trigger_data *test, *named_data = NULL;
6526 	bool updated = false;
6527 
6528 	if (!hist_data->attrs->pause && !hist_data->attrs->cont &&
6529 	    !hist_data->attrs->clear)
6530 		goto out;
6531 
6532 	if (hist_data->attrs->name) {
6533 		named_data = find_named_trigger(hist_data->attrs->name);
6534 		if (named_data) {
6535 			if (!hist_trigger_match(data, named_data, named_data,
6536 						true))
6537 				goto out;
6538 		}
6539 	}
6540 
6541 	if (hist_data->attrs->name && !named_data)
6542 		goto out;
6543 
6544 	list_for_each_entry(test, &file->triggers, list) {
6545 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6546 			if (!hist_trigger_match(data, test, named_data, false))
6547 				continue;
6548 			if (hist_data->attrs->pause)
6549 				test->paused = true;
6550 			else if (hist_data->attrs->cont)
6551 				test->paused = false;
6552 			else if (hist_data->attrs->clear)
6553 				hist_clear(test);
6554 			updated = true;
6555 			goto out;
6556 		}
6557 	}
6558  out:
6559 	return updated;
6560 }
6561 
6562 /*
6563  * Set or disable using the per CPU trace_buffer_event when possible.
6564  */
6565 static int tracing_set_filter_buffering(struct trace_array *tr, bool set)
6566 {
6567 	guard(mutex)(&trace_types_lock);
6568 
6569 	if (set && tr->no_filter_buffering_ref++)
6570 		return 0;
6571 
6572 	if (!set) {
6573 		if (WARN_ON_ONCE(!tr->no_filter_buffering_ref))
6574 			return -EINVAL;
6575 
6576 		--tr->no_filter_buffering_ref;
6577 	}
6578 
6579 	return 0;
6580 }
6581 
6582 static int hist_register_trigger(char *glob,
6583 				 struct event_trigger_data *data,
6584 				 struct trace_event_file *file)
6585 {
6586 	struct hist_trigger_data *hist_data = data->private_data;
6587 	struct event_trigger_data *test, *named_data = NULL;
6588 	struct trace_array *tr = file->tr;
6589 	int ret = 0;
6590 
6591 	if (hist_data->attrs->name) {
6592 		named_data = find_named_trigger(hist_data->attrs->name);
6593 		if (named_data) {
6594 			if (!hist_trigger_match(data, named_data, named_data,
6595 						true)) {
6596 				hist_err(tr, HIST_ERR_NAMED_MISMATCH, errpos(hist_data->attrs->name));
6597 				ret = -EINVAL;
6598 				goto out;
6599 			}
6600 		}
6601 	}
6602 
6603 	if (hist_data->attrs->name && !named_data)
6604 		goto new;
6605 
6606 	lockdep_assert_held(&event_mutex);
6607 
6608 	list_for_each_entry(test, &file->triggers, list) {
6609 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6610 			if (hist_trigger_match(data, test, named_data, false)) {
6611 				hist_err(tr, HIST_ERR_TRIGGER_EEXIST, 0);
6612 				ret = -EEXIST;
6613 				goto out;
6614 			}
6615 		}
6616 	}
6617  new:
6618 	if (hist_data->attrs->cont || hist_data->attrs->clear) {
6619 		hist_err(tr, HIST_ERR_TRIGGER_ENOENT_CLEAR, 0);
6620 		ret = -ENOENT;
6621 		goto out;
6622 	}
6623 
6624 	if (hist_data->attrs->pause)
6625 		data->paused = true;
6626 
6627 	if (named_data) {
6628 		struct event_command *cmd_ops;
6629 
6630 		data->private_data = named_data->private_data;
6631 		set_named_trigger_data(data, named_data);
6632 		/* Copy the command ops and update some of the functions */
6633 		cmd_ops = kmalloc_obj(*cmd_ops);
6634 		if (!cmd_ops) {
6635 			ret = -ENOMEM;
6636 			goto out;
6637 		}
6638 		*cmd_ops = *data->cmd_ops;
6639 		cmd_ops->init = event_hist_trigger_named_init;
6640 		cmd_ops->free = event_hist_trigger_named_free;
6641 		data->cmd_ops = cmd_ops;
6642 	}
6643 
6644 	if (hist_data->enable_timestamps) {
6645 		char *clock = hist_data->attrs->clock;
6646 
6647 		ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
6648 		if (ret) {
6649 			hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
6650 			goto out;
6651 		}
6652 
6653 		tracing_set_filter_buffering(file->tr, true);
6654 	}
6655 
6656 	if (data->cmd_ops->init) {
6657 		ret = data->cmd_ops->init(data);
6658 		if (ret < 0) {
6659 			if (hist_data->enable_timestamps)
6660 				tracing_set_filter_buffering(file->tr, false);
6661 			goto out;
6662 		}
6663 	}
6664 
6665 	if (named_data) {
6666 		remove_hist_vars(hist_data);
6667 		destroy_hist_data(hist_data);
6668 	}
6669  out:
6670 	return ret;
6671 }
6672 
6673 static int hist_trigger_enable(struct event_trigger_data *data,
6674 			       struct trace_event_file *file)
6675 {
6676 	int ret = 0;
6677 
6678 	list_add_tail_rcu(&data->list, &file->triggers);
6679 
6680 	update_cond_flag(file);
6681 
6682 	/*
6683 	 * On failure the caller undoes the registration, and
6684 	 * hist_unregister_trigger() can only find the trigger here.
6685 	 */
6686 	if (trace_event_trigger_enable_disable(file, 1) < 0)
6687 		ret--;
6688 
6689 	return ret;
6690 }
6691 
6692 static bool have_hist_trigger_match(struct event_trigger_data *data,
6693 				    struct trace_event_file *file)
6694 {
6695 	struct hist_trigger_data *hist_data = data->private_data;
6696 	struct event_trigger_data *test, *named_data = NULL;
6697 	bool match = false;
6698 
6699 	lockdep_assert_held(&event_mutex);
6700 
6701 	if (hist_data->attrs->name)
6702 		named_data = find_named_trigger(hist_data->attrs->name);
6703 
6704 	list_for_each_entry(test, &file->triggers, list) {
6705 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6706 			if (hist_trigger_match(data, test, named_data, false)) {
6707 				match = true;
6708 				break;
6709 			}
6710 		}
6711 	}
6712 
6713 	return match;
6714 }
6715 
6716 static bool hist_trigger_check_refs(struct event_trigger_data *data,
6717 				    struct trace_event_file *file)
6718 {
6719 	struct hist_trigger_data *hist_data = data->private_data;
6720 	struct event_trigger_data *test, *named_data = NULL;
6721 
6722 	lockdep_assert_held(&event_mutex);
6723 
6724 	if (hist_data->attrs->name)
6725 		named_data = find_named_trigger(hist_data->attrs->name);
6726 
6727 	list_for_each_entry(test, &file->triggers, list) {
6728 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6729 			if (!hist_trigger_match(data, test, named_data, false))
6730 				continue;
6731 			hist_data = test->private_data;
6732 			if (check_var_refs(hist_data))
6733 				return true;
6734 			break;
6735 		}
6736 	}
6737 
6738 	return false;
6739 }
6740 
6741 static void hist_unregister_trigger(char *glob,
6742 				    struct event_trigger_data *data,
6743 				    struct trace_event_file *file)
6744 {
6745 	struct event_trigger_data *test = NULL, *iter, *named_data = NULL;
6746 	struct hist_trigger_data *hist_data = data->private_data;
6747 
6748 	lockdep_assert_held(&event_mutex);
6749 
6750 	if (hist_data->attrs->name)
6751 		named_data = find_named_trigger(hist_data->attrs->name);
6752 
6753 	list_for_each_entry(iter, &file->triggers, list) {
6754 		if (iter->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6755 			if (!hist_trigger_match(data, iter, named_data, false))
6756 				continue;
6757 			test = iter;
6758 			list_del_rcu(&test->list);
6759 			trace_event_trigger_enable_disable(file, 0);
6760 			update_cond_flag(file);
6761 			break;
6762 		}
6763 	}
6764 
6765 	if (hist_data->enable_timestamps) {
6766 		if (!hist_data->remove || test)
6767 			tracing_set_filter_buffering(file->tr, false);
6768 	}
6769 
6770 	if (test && test->cmd_ops->free)
6771 		test->cmd_ops->free(test);
6772 }
6773 
6774 static bool hist_file_check_refs(struct trace_event_file *file)
6775 {
6776 	struct hist_trigger_data *hist_data;
6777 	struct event_trigger_data *test;
6778 
6779 	lockdep_assert_held(&event_mutex);
6780 
6781 	list_for_each_entry(test, &file->triggers, list) {
6782 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6783 			hist_data = test->private_data;
6784 			if (check_var_refs(hist_data))
6785 				return true;
6786 		}
6787 	}
6788 
6789 	return false;
6790 }
6791 
6792 static void hist_unreg_all(struct trace_event_file *file)
6793 {
6794 	struct event_trigger_data *test, *n;
6795 	struct hist_trigger_data *hist_data;
6796 	struct synth_event *se;
6797 	const char *se_name;
6798 
6799 	lockdep_assert_held(&event_mutex);
6800 
6801 	if (hist_file_check_refs(file))
6802 		return;
6803 
6804 	list_for_each_entry_safe(test, n, &file->triggers, list) {
6805 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
6806 			hist_data = test->private_data;
6807 			list_del_rcu(&test->list);
6808 			trace_event_trigger_enable_disable(file, 0);
6809 
6810 			se_name = trace_event_name(file->event_call);
6811 			se = find_synth_event(se_name);
6812 			if (se)
6813 				se->ref--;
6814 
6815 			update_cond_flag(file);
6816 			if (hist_data->enable_timestamps)
6817 				tracing_set_filter_buffering(file->tr, false);
6818 			if (test->cmd_ops->free)
6819 				test->cmd_ops->free(test);
6820 		}
6821 	}
6822 }
6823 
6824 static int event_hist_trigger_parse(struct event_command *cmd_ops,
6825 				    struct trace_event_file *file,
6826 				    char *glob, char *cmd,
6827 				    char *param_and_filter)
6828 {
6829 	unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
6830 	struct event_trigger_data *trigger_data;
6831 	struct hist_trigger_attrs *attrs;
6832 	struct hist_trigger_data *hist_data;
6833 	char *param, *filter, *p, *start;
6834 	struct synth_event *se;
6835 	const char *se_name;
6836 	bool remove;
6837 	int ret = 0;
6838 
6839 	lockdep_assert_held(&event_mutex);
6840 
6841 	if (WARN_ON(!glob))
6842 		return -EINVAL;
6843 
6844 	if (glob[0]) {
6845 		hist_err_clear();
6846 		last_cmd_set(file, param_and_filter);
6847 	}
6848 
6849 	remove = event_trigger_check_remove(glob);
6850 
6851 	if (event_trigger_empty_param(param_and_filter))
6852 		return -EINVAL;
6853 
6854 	/*
6855 	 * separate the trigger from the filter (k:v [if filter])
6856 	 * allowing for whitespace in the trigger
6857 	 */
6858 	p = param = param_and_filter;
6859 	do {
6860 		p = strstr(p, "if");
6861 		if (!p)
6862 			break;
6863 		if (p == param_and_filter)
6864 			return -EINVAL;
6865 		if (*(p - 1) != ' ' && *(p - 1) != '\t') {
6866 			p++;
6867 			continue;
6868 		}
6869 		if (p >= param_and_filter + strlen(param_and_filter) - (sizeof("if") - 1) - 1)
6870 			return -EINVAL;
6871 		if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
6872 			p++;
6873 			continue;
6874 		}
6875 		break;
6876 	} while (1);
6877 
6878 	if (!p)
6879 		filter = NULL;
6880 	else {
6881 		*(p - 1) = '\0';
6882 		filter = strstrip(p);
6883 		param = strstrip(param);
6884 	}
6885 
6886 	/*
6887 	 * To simplify arithmetic expression parsing, replace occurrences of
6888 	 * '.sym-offset' modifier with '.symXoffset'
6889 	 */
6890 	start = strstr(param, ".sym-offset");
6891 	while (start) {
6892 		*(start + 4) = 'X';
6893 		start = strstr(start + 11, ".sym-offset");
6894 	}
6895 
6896 	attrs = parse_hist_trigger_attrs(file->tr, param);
6897 	if (IS_ERR(attrs))
6898 		return PTR_ERR(attrs);
6899 
6900 	if (attrs->map_bits)
6901 		hist_trigger_bits = attrs->map_bits;
6902 
6903 	hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
6904 	if (IS_ERR(hist_data)) {
6905 		destroy_hist_trigger_attrs(attrs);
6906 		return PTR_ERR(hist_data);
6907 	}
6908 
6909 	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, hist_data);
6910 	if (!trigger_data) {
6911 		ret = -ENOMEM;
6912 		goto out_free;
6913 	}
6914 
6915 	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
6916 	if (ret < 0)
6917 		goto out_free;
6918 
6919 	if (remove) {
6920 		if (!have_hist_trigger_match(trigger_data, file))
6921 			goto out_free;
6922 
6923 		if (hist_trigger_check_refs(trigger_data, file)) {
6924 			ret = -EBUSY;
6925 			goto out_free;
6926 		}
6927 
6928 		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
6929 		se_name = trace_event_name(file->event_call);
6930 		se = find_synth_event(se_name);
6931 		if (se)
6932 			se->ref--;
6933 		ret = 0;
6934 		goto out_free;
6935 	}
6936 
6937 	if (existing_hist_update_only(glob, trigger_data, file))
6938 		goto out_free;
6939 
6940 	if (!get_named_trigger_data(trigger_data)) {
6941 
6942 		ret = create_actions(hist_data);
6943 		if (ret)
6944 			goto out_free;
6945 
6946 		if (has_hist_vars(hist_data) || hist_data->n_var_refs) {
6947 			ret = save_hist_vars(hist_data);
6948 			if (ret)
6949 				goto out_free;
6950 		}
6951 
6952 		ret = tracing_map_init(hist_data->map);
6953 		if (ret)
6954 			goto out_free;
6955 	}
6956 
6957 	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
6958 	if (ret < 0)
6959 		goto out_free;
6960 
6961 	ret = hist_trigger_enable(trigger_data, file);
6962 	if (ret)
6963 		goto out_unreg;
6964 
6965 	se_name = trace_event_name(file->event_call);
6966 	se = find_synth_event(se_name);
6967 	if (se)
6968 		se->ref++;
6969  out:
6970 	if (ret == 0 && glob[0])
6971 		hist_err_clear();
6972 
6973 	return ret;
6974  out_unreg:
6975 	event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
6976 	/* The unregister frees trigger_data, skip out_free */
6977 	goto out;
6978  out_free:
6979 	remove_hist_vars(hist_data);
6980 
6981 	trigger_data_free(trigger_data);
6982 
6983 	destroy_hist_data(hist_data);
6984 	goto out;
6985 }
6986 
6987 static struct event_command trigger_hist_cmd = {
6988 	.name			= "hist",
6989 	.trigger_type		= ETT_EVENT_HIST,
6990 	.flags			= EVENT_CMD_FL_NEEDS_REC,
6991 	.parse			= event_hist_trigger_parse,
6992 	.reg			= hist_register_trigger,
6993 	.unreg			= hist_unregister_trigger,
6994 	.unreg_all		= hist_unreg_all,
6995 	.set_filter		= set_trigger_filter,
6996 	.trigger		= event_hist_trigger,
6997 	.print			= event_hist_trigger_print,
6998 	.init			= event_hist_trigger_init,
6999 	.free			= event_hist_trigger_free,
7000 };
7001 
7002 __init int register_trigger_hist_cmd(void)
7003 {
7004 	int ret;
7005 
7006 	ret = register_event_command(&trigger_hist_cmd);
7007 	WARN_ON(ret < 0);
7008 
7009 	return ret;
7010 }
7011 
7012 static void
7013 hist_enable_trigger(struct event_trigger_data *data,
7014 		    struct trace_buffer *buffer,  void *rec,
7015 		    struct ring_buffer_event *event)
7016 {
7017 	struct enable_trigger_data *enable_data = data->private_data;
7018 	struct event_trigger_data *test;
7019 
7020 	list_for_each_entry_rcu(test, &enable_data->file->triggers, list,
7021 				lockdep_is_held(&event_mutex)) {
7022 		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
7023 			if (enable_data->enable)
7024 				test->paused = false;
7025 			else
7026 				test->paused = true;
7027 		}
7028 	}
7029 }
7030 
7031 static void hist_enable_unreg_all(struct trace_event_file *file)
7032 {
7033 	struct event_trigger_data *test, *n;
7034 
7035 	list_for_each_entry_safe(test, n, &file->triggers, list) {
7036 		if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
7037 			list_del_rcu(&test->list);
7038 			update_cond_flag(file);
7039 			trace_event_trigger_enable_disable(file, 0);
7040 			if (test->cmd_ops->free)
7041 				test->cmd_ops->free(test);
7042 		}
7043 	}
7044 }
7045 
7046 static struct event_command trigger_hist_enable_cmd = {
7047 	.name			= ENABLE_HIST_STR,
7048 	.trigger_type		= ETT_HIST_ENABLE,
7049 	.parse			= event_enable_trigger_parse,
7050 	.reg			= event_enable_register_trigger,
7051 	.unreg			= event_enable_unregister_trigger,
7052 	.unreg_all		= hist_enable_unreg_all,
7053 	.set_filter		= set_trigger_filter,
7054 	.trigger		= hist_enable_trigger,
7055 	.count_func		= event_trigger_count,
7056 	.print			= event_enable_trigger_print,
7057 	.init			= event_trigger_init,
7058 	.free			= event_enable_trigger_free,
7059 };
7060 
7061 static struct event_command trigger_hist_disable_cmd = {
7062 	.name			= DISABLE_HIST_STR,
7063 	.trigger_type		= ETT_HIST_ENABLE,
7064 	.parse			= event_enable_trigger_parse,
7065 	.reg			= event_enable_register_trigger,
7066 	.unreg			= event_enable_unregister_trigger,
7067 	.unreg_all		= hist_enable_unreg_all,
7068 	.set_filter		= set_trigger_filter,
7069 	.trigger		= hist_enable_trigger,
7070 	.count_func		= event_trigger_count,
7071 	.print			= event_enable_trigger_print,
7072 	.init			= event_trigger_init,
7073 	.free			= event_enable_trigger_free,
7074 };
7075 
7076 static __init void unregister_trigger_hist_enable_disable_cmds(void)
7077 {
7078 	unregister_event_command(&trigger_hist_enable_cmd);
7079 	unregister_event_command(&trigger_hist_disable_cmd);
7080 }
7081 
7082 __init int register_trigger_hist_enable_disable_cmds(void)
7083 {
7084 	int ret;
7085 
7086 	ret = register_event_command(&trigger_hist_enable_cmd);
7087 	if (WARN_ON(ret < 0))
7088 		return ret;
7089 	ret = register_event_command(&trigger_hist_disable_cmd);
7090 	if (WARN_ON(ret < 0))
7091 		unregister_trigger_hist_enable_disable_cmds();
7092 
7093 	return ret;
7094 }
7095