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