xref: /linux/kernel/trace/trace_events_synth.c (revision 26fbb4c8c7c3ee9a4c3b4de555a8587b5a19154e)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * trace_events_synth - synthetic trace events
4  *
5  * Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/kallsyms.h>
10 #include <linux/security.h>
11 #include <linux/mutex.h>
12 #include <linux/slab.h>
13 #include <linux/stacktrace.h>
14 #include <linux/rculist.h>
15 #include <linux/tracefs.h>
16 
17 /* for gfp flag names */
18 #include <linux/trace_events.h>
19 #include <trace/events/mmflags.h>
20 
21 #include "trace_synth.h"
22 
23 #undef ERRORS
24 #define ERRORS	\
25 	C(BAD_NAME,		"Illegal name"),		\
26 	C(CMD_INCOMPLETE,	"Incomplete command"),		\
27 	C(EVENT_EXISTS,		"Event already exists"),	\
28 	C(TOO_MANY_FIELDS,	"Too many fields"),		\
29 	C(INCOMPLETE_TYPE,	"Incomplete type"),		\
30 	C(INVALID_TYPE,		"Invalid type"),		\
31 	C(INVALID_FIELD,	"Invalid field"),		\
32 	C(CMD_TOO_LONG,		"Command too long"),
33 
34 #undef C
35 #define C(a, b)		SYNTH_ERR_##a
36 
37 enum { ERRORS };
38 
39 #undef C
40 #define C(a, b)		b
41 
42 static const char *err_text[] = { ERRORS };
43 
44 static char last_cmd[MAX_FILTER_STR_VAL];
45 
46 static int errpos(const char *str)
47 {
48 	return err_pos(last_cmd, str);
49 }
50 
51 static void last_cmd_set(char *str)
52 {
53 	if (!str)
54 		return;
55 
56 	strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
57 }
58 
59 static void synth_err(u8 err_type, u8 err_pos)
60 {
61 	tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
62 			err_type, err_pos);
63 }
64 
65 static int create_synth_event(int argc, const char **argv);
66 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
67 static int synth_event_release(struct dyn_event *ev);
68 static bool synth_event_is_busy(struct dyn_event *ev);
69 static bool synth_event_match(const char *system, const char *event,
70 			int argc, const char **argv, struct dyn_event *ev);
71 
72 static struct dyn_event_operations synth_event_ops = {
73 	.create = create_synth_event,
74 	.show = synth_event_show,
75 	.is_busy = synth_event_is_busy,
76 	.free = synth_event_release,
77 	.match = synth_event_match,
78 };
79 
80 static bool is_synth_event(struct dyn_event *ev)
81 {
82 	return ev->ops == &synth_event_ops;
83 }
84 
85 static struct synth_event *to_synth_event(struct dyn_event *ev)
86 {
87 	return container_of(ev, struct synth_event, devent);
88 }
89 
90 static bool synth_event_is_busy(struct dyn_event *ev)
91 {
92 	struct synth_event *event = to_synth_event(ev);
93 
94 	return event->ref != 0;
95 }
96 
97 static bool synth_event_match(const char *system, const char *event,
98 			int argc, const char **argv, struct dyn_event *ev)
99 {
100 	struct synth_event *sev = to_synth_event(ev);
101 
102 	return strcmp(sev->name, event) == 0 &&
103 		(!system || strcmp(system, SYNTH_SYSTEM) == 0);
104 }
105 
106 struct synth_trace_event {
107 	struct trace_entry	ent;
108 	u64			fields[];
109 };
110 
111 static int synth_event_define_fields(struct trace_event_call *call)
112 {
113 	struct synth_trace_event trace;
114 	int offset = offsetof(typeof(trace), fields);
115 	struct synth_event *event = call->data;
116 	unsigned int i, size, n_u64;
117 	char *name, *type;
118 	bool is_signed;
119 	int ret = 0;
120 
121 	for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
122 		size = event->fields[i]->size;
123 		is_signed = event->fields[i]->is_signed;
124 		type = event->fields[i]->type;
125 		name = event->fields[i]->name;
126 		ret = trace_define_field(call, type, name, offset, size,
127 					 is_signed, FILTER_OTHER);
128 		if (ret)
129 			break;
130 
131 		event->fields[i]->offset = n_u64;
132 
133 		if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
134 			offset += STR_VAR_LEN_MAX;
135 			n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
136 		} else {
137 			offset += sizeof(u64);
138 			n_u64++;
139 		}
140 	}
141 
142 	event->n_u64 = n_u64;
143 
144 	return ret;
145 }
146 
147 static bool synth_field_signed(char *type)
148 {
149 	if (str_has_prefix(type, "u"))
150 		return false;
151 	if (strcmp(type, "gfp_t") == 0)
152 		return false;
153 
154 	return true;
155 }
156 
157 static int synth_field_is_string(char *type)
158 {
159 	if (strstr(type, "char[") != NULL)
160 		return true;
161 
162 	return false;
163 }
164 
165 static int synth_field_string_size(char *type)
166 {
167 	char buf[4], *end, *start;
168 	unsigned int len;
169 	int size, err;
170 
171 	start = strstr(type, "char[");
172 	if (start == NULL)
173 		return -EINVAL;
174 	start += sizeof("char[") - 1;
175 
176 	end = strchr(type, ']');
177 	if (!end || end < start || type + strlen(type) > end + 1)
178 		return -EINVAL;
179 
180 	len = end - start;
181 	if (len > 3)
182 		return -EINVAL;
183 
184 	if (len == 0)
185 		return 0; /* variable-length string */
186 
187 	strncpy(buf, start, len);
188 	buf[len] = '\0';
189 
190 	err = kstrtouint(buf, 0, &size);
191 	if (err)
192 		return err;
193 
194 	if (size > STR_VAR_LEN_MAX)
195 		return -EINVAL;
196 
197 	return size;
198 }
199 
200 static int synth_field_size(char *type)
201 {
202 	int size = 0;
203 
204 	if (strcmp(type, "s64") == 0)
205 		size = sizeof(s64);
206 	else if (strcmp(type, "u64") == 0)
207 		size = sizeof(u64);
208 	else if (strcmp(type, "s32") == 0)
209 		size = sizeof(s32);
210 	else if (strcmp(type, "u32") == 0)
211 		size = sizeof(u32);
212 	else if (strcmp(type, "s16") == 0)
213 		size = sizeof(s16);
214 	else if (strcmp(type, "u16") == 0)
215 		size = sizeof(u16);
216 	else if (strcmp(type, "s8") == 0)
217 		size = sizeof(s8);
218 	else if (strcmp(type, "u8") == 0)
219 		size = sizeof(u8);
220 	else if (strcmp(type, "char") == 0)
221 		size = sizeof(char);
222 	else if (strcmp(type, "unsigned char") == 0)
223 		size = sizeof(unsigned char);
224 	else if (strcmp(type, "int") == 0)
225 		size = sizeof(int);
226 	else if (strcmp(type, "unsigned int") == 0)
227 		size = sizeof(unsigned int);
228 	else if (strcmp(type, "long") == 0)
229 		size = sizeof(long);
230 	else if (strcmp(type, "unsigned long") == 0)
231 		size = sizeof(unsigned long);
232 	else if (strcmp(type, "bool") == 0)
233 		size = sizeof(bool);
234 	else if (strcmp(type, "pid_t") == 0)
235 		size = sizeof(pid_t);
236 	else if (strcmp(type, "gfp_t") == 0)
237 		size = sizeof(gfp_t);
238 	else if (synth_field_is_string(type))
239 		size = synth_field_string_size(type);
240 
241 	return size;
242 }
243 
244 static const char *synth_field_fmt(char *type)
245 {
246 	const char *fmt = "%llu";
247 
248 	if (strcmp(type, "s64") == 0)
249 		fmt = "%lld";
250 	else if (strcmp(type, "u64") == 0)
251 		fmt = "%llu";
252 	else if (strcmp(type, "s32") == 0)
253 		fmt = "%d";
254 	else if (strcmp(type, "u32") == 0)
255 		fmt = "%u";
256 	else if (strcmp(type, "s16") == 0)
257 		fmt = "%d";
258 	else if (strcmp(type, "u16") == 0)
259 		fmt = "%u";
260 	else if (strcmp(type, "s8") == 0)
261 		fmt = "%d";
262 	else if (strcmp(type, "u8") == 0)
263 		fmt = "%u";
264 	else if (strcmp(type, "char") == 0)
265 		fmt = "%d";
266 	else if (strcmp(type, "unsigned char") == 0)
267 		fmt = "%u";
268 	else if (strcmp(type, "int") == 0)
269 		fmt = "%d";
270 	else if (strcmp(type, "unsigned int") == 0)
271 		fmt = "%u";
272 	else if (strcmp(type, "long") == 0)
273 		fmt = "%ld";
274 	else if (strcmp(type, "unsigned long") == 0)
275 		fmt = "%lu";
276 	else if (strcmp(type, "bool") == 0)
277 		fmt = "%d";
278 	else if (strcmp(type, "pid_t") == 0)
279 		fmt = "%d";
280 	else if (strcmp(type, "gfp_t") == 0)
281 		fmt = "%x";
282 	else if (synth_field_is_string(type))
283 		fmt = "%.*s";
284 
285 	return fmt;
286 }
287 
288 static void print_synth_event_num_val(struct trace_seq *s,
289 				      char *print_fmt, char *name,
290 				      int size, u64 val, char *space)
291 {
292 	switch (size) {
293 	case 1:
294 		trace_seq_printf(s, print_fmt, name, (u8)val, space);
295 		break;
296 
297 	case 2:
298 		trace_seq_printf(s, print_fmt, name, (u16)val, space);
299 		break;
300 
301 	case 4:
302 		trace_seq_printf(s, print_fmt, name, (u32)val, space);
303 		break;
304 
305 	default:
306 		trace_seq_printf(s, print_fmt, name, val, space);
307 		break;
308 	}
309 }
310 
311 static enum print_line_t print_synth_event(struct trace_iterator *iter,
312 					   int flags,
313 					   struct trace_event *event)
314 {
315 	struct trace_array *tr = iter->tr;
316 	struct trace_seq *s = &iter->seq;
317 	struct synth_trace_event *entry;
318 	struct synth_event *se;
319 	unsigned int i, n_u64;
320 	char print_fmt[32];
321 	const char *fmt;
322 
323 	entry = (struct synth_trace_event *)iter->ent;
324 	se = container_of(event, struct synth_event, call.event);
325 
326 	trace_seq_printf(s, "%s: ", se->name);
327 
328 	for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
329 		if (trace_seq_has_overflowed(s))
330 			goto end;
331 
332 		fmt = synth_field_fmt(se->fields[i]->type);
333 
334 		/* parameter types */
335 		if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
336 			trace_seq_printf(s, "%s ", fmt);
337 
338 		snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
339 
340 		/* parameter values */
341 		if (se->fields[i]->is_string) {
342 			if (se->fields[i]->is_dynamic) {
343 				u32 offset, data_offset;
344 				char *str_field;
345 
346 				offset = (u32)entry->fields[n_u64];
347 				data_offset = offset & 0xffff;
348 
349 				str_field = (char *)entry + data_offset;
350 
351 				trace_seq_printf(s, print_fmt, se->fields[i]->name,
352 						 STR_VAR_LEN_MAX,
353 						 str_field,
354 						 i == se->n_fields - 1 ? "" : " ");
355 				n_u64++;
356 			} else {
357 				trace_seq_printf(s, print_fmt, se->fields[i]->name,
358 						 STR_VAR_LEN_MAX,
359 						 (char *)&entry->fields[n_u64],
360 						 i == se->n_fields - 1 ? "" : " ");
361 				n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
362 			}
363 		} else {
364 			struct trace_print_flags __flags[] = {
365 			    __def_gfpflag_names, {-1, NULL} };
366 			char *space = (i == se->n_fields - 1 ? "" : " ");
367 
368 			print_synth_event_num_val(s, print_fmt,
369 						  se->fields[i]->name,
370 						  se->fields[i]->size,
371 						  entry->fields[n_u64],
372 						  space);
373 
374 			if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
375 				trace_seq_puts(s, " (");
376 				trace_print_flags_seq(s, "|",
377 						      entry->fields[n_u64],
378 						      __flags);
379 				trace_seq_putc(s, ')');
380 			}
381 			n_u64++;
382 		}
383 	}
384 end:
385 	trace_seq_putc(s, '\n');
386 
387 	return trace_handle_return(s);
388 }
389 
390 static struct trace_event_functions synth_event_funcs = {
391 	.trace		= print_synth_event
392 };
393 
394 static unsigned int trace_string(struct synth_trace_event *entry,
395 				 struct synth_event *event,
396 				 char *str_val,
397 				 bool is_dynamic,
398 				 unsigned int data_size,
399 				 unsigned int *n_u64)
400 {
401 	unsigned int len = 0;
402 	char *str_field;
403 
404 	if (is_dynamic) {
405 		u32 data_offset;
406 
407 		data_offset = offsetof(typeof(*entry), fields);
408 		data_offset += event->n_u64 * sizeof(u64);
409 		data_offset += data_size;
410 
411 		str_field = (char *)entry + data_offset;
412 
413 		len = strlen(str_val) + 1;
414 		strscpy(str_field, str_val, len);
415 
416 		data_offset |= len << 16;
417 		*(u32 *)&entry->fields[*n_u64] = data_offset;
418 
419 		(*n_u64)++;
420 	} else {
421 		str_field = (char *)&entry->fields[*n_u64];
422 
423 		strscpy(str_field, str_val, STR_VAR_LEN_MAX);
424 		(*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
425 	}
426 
427 	return len;
428 }
429 
430 static notrace void trace_event_raw_event_synth(void *__data,
431 						u64 *var_ref_vals,
432 						unsigned int *var_ref_idx)
433 {
434 	unsigned int i, n_u64, val_idx, len, data_size = 0;
435 	struct trace_event_file *trace_file = __data;
436 	struct synth_trace_event *entry;
437 	struct trace_event_buffer fbuffer;
438 	struct trace_buffer *buffer;
439 	struct synth_event *event;
440 	int fields_size = 0;
441 
442 	event = trace_file->event_call->data;
443 
444 	if (trace_trigger_soft_disabled(trace_file))
445 		return;
446 
447 	fields_size = event->n_u64 * sizeof(u64);
448 
449 	for (i = 0; i < event->n_dynamic_fields; i++) {
450 		unsigned int field_pos = event->dynamic_fields[i]->field_pos;
451 		char *str_val;
452 
453 		val_idx = var_ref_idx[field_pos];
454 		str_val = (char *)(long)var_ref_vals[val_idx];
455 
456 		len = strlen(str_val) + 1;
457 
458 		fields_size += len;
459 	}
460 
461 	/*
462 	 * Avoid ring buffer recursion detection, as this event
463 	 * is being performed within another event.
464 	 */
465 	buffer = trace_file->tr->array_buffer.buffer;
466 	ring_buffer_nest_start(buffer);
467 
468 	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
469 					   sizeof(*entry) + fields_size);
470 	if (!entry)
471 		goto out;
472 
473 	for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
474 		val_idx = var_ref_idx[i];
475 		if (event->fields[i]->is_string) {
476 			char *str_val = (char *)(long)var_ref_vals[val_idx];
477 
478 			len = trace_string(entry, event, str_val,
479 					   event->fields[i]->is_dynamic,
480 					   data_size, &n_u64);
481 			data_size += len; /* only dynamic string increments */
482 		} else {
483 			struct synth_field *field = event->fields[i];
484 			u64 val = var_ref_vals[val_idx];
485 
486 			switch (field->size) {
487 			case 1:
488 				*(u8 *)&entry->fields[n_u64] = (u8)val;
489 				break;
490 
491 			case 2:
492 				*(u16 *)&entry->fields[n_u64] = (u16)val;
493 				break;
494 
495 			case 4:
496 				*(u32 *)&entry->fields[n_u64] = (u32)val;
497 				break;
498 
499 			default:
500 				entry->fields[n_u64] = val;
501 				break;
502 			}
503 			n_u64++;
504 		}
505 	}
506 
507 	trace_event_buffer_commit(&fbuffer);
508 out:
509 	ring_buffer_nest_end(buffer);
510 }
511 
512 static void free_synth_event_print_fmt(struct trace_event_call *call)
513 {
514 	if (call) {
515 		kfree(call->print_fmt);
516 		call->print_fmt = NULL;
517 	}
518 }
519 
520 static int __set_synth_event_print_fmt(struct synth_event *event,
521 				       char *buf, int len)
522 {
523 	const char *fmt;
524 	int pos = 0;
525 	int i;
526 
527 	/* When len=0, we just calculate the needed length */
528 #define LEN_OR_ZERO (len ? len - pos : 0)
529 
530 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
531 	for (i = 0; i < event->n_fields; i++) {
532 		fmt = synth_field_fmt(event->fields[i]->type);
533 		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
534 				event->fields[i]->name, fmt,
535 				i == event->n_fields - 1 ? "" : ", ");
536 	}
537 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
538 
539 	for (i = 0; i < event->n_fields; i++) {
540 		if (event->fields[i]->is_string &&
541 		    event->fields[i]->is_dynamic)
542 			pos += snprintf(buf + pos, LEN_OR_ZERO,
543 				", __get_str(%s)", event->fields[i]->name);
544 		else
545 			pos += snprintf(buf + pos, LEN_OR_ZERO,
546 					", REC->%s", event->fields[i]->name);
547 	}
548 
549 #undef LEN_OR_ZERO
550 
551 	/* return the length of print_fmt */
552 	return pos;
553 }
554 
555 static int set_synth_event_print_fmt(struct trace_event_call *call)
556 {
557 	struct synth_event *event = call->data;
558 	char *print_fmt;
559 	int len;
560 
561 	/* First: called with 0 length to calculate the needed length */
562 	len = __set_synth_event_print_fmt(event, NULL, 0);
563 
564 	print_fmt = kmalloc(len + 1, GFP_KERNEL);
565 	if (!print_fmt)
566 		return -ENOMEM;
567 
568 	/* Second: actually write the @print_fmt */
569 	__set_synth_event_print_fmt(event, print_fmt, len + 1);
570 	call->print_fmt = print_fmt;
571 
572 	return 0;
573 }
574 
575 static void free_synth_field(struct synth_field *field)
576 {
577 	kfree(field->type);
578 	kfree(field->name);
579 	kfree(field);
580 }
581 
582 static struct synth_field *parse_synth_field(int argc, const char **argv,
583 					     int *consumed)
584 {
585 	struct synth_field *field;
586 	const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
587 	int len, ret = -ENOMEM;
588 	struct seq_buf s;
589 	ssize_t size;
590 
591 	if (field_type[0] == ';')
592 		field_type++;
593 
594 	if (!strcmp(field_type, "unsigned")) {
595 		if (argc < 3) {
596 			synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
597 			return ERR_PTR(-EINVAL);
598 		}
599 		prefix = "unsigned ";
600 		field_type = argv[1];
601 		field_name = argv[2];
602 		*consumed = 3;
603 	} else {
604 		field_name = argv[1];
605 		*consumed = 2;
606 	}
607 
608 	field = kzalloc(sizeof(*field), GFP_KERNEL);
609 	if (!field)
610 		return ERR_PTR(-ENOMEM);
611 
612 	len = strlen(field_name);
613 	array = strchr(field_name, '[');
614 	if (array)
615 		len -= strlen(array);
616 	else if (field_name[len - 1] == ';')
617 		len--;
618 
619 	field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
620 	if (!field->name)
621 		goto free;
622 
623 	if (!is_good_name(field->name)) {
624 		synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
625 		ret = -EINVAL;
626 		goto free;
627 	}
628 
629 	if (field_type[0] == ';')
630 		field_type++;
631 	len = strlen(field_type) + 1;
632 
633 	if (array)
634 		len += strlen(array);
635 
636 	if (prefix)
637 		len += strlen(prefix);
638 
639 	field->type = kzalloc(len, GFP_KERNEL);
640 	if (!field->type)
641 		goto free;
642 
643 	seq_buf_init(&s, field->type, len);
644 	if (prefix)
645 		seq_buf_puts(&s, prefix);
646 	seq_buf_puts(&s, field_type);
647 	if (array) {
648 		seq_buf_puts(&s, array);
649 		if (s.buffer[s.len - 1] == ';')
650 			s.len--;
651 	}
652 	if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
653 		goto free;
654 
655 	s.buffer[s.len] = '\0';
656 
657 	size = synth_field_size(field->type);
658 	if (size < 0) {
659 		synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
660 		ret = -EINVAL;
661 		goto free;
662 	} else if (size == 0) {
663 		if (synth_field_is_string(field->type)) {
664 			char *type;
665 
666 			len = sizeof("__data_loc ") + strlen(field->type) + 1;
667 			type = kzalloc(len, GFP_KERNEL);
668 			if (!type)
669 				goto free;
670 
671 			seq_buf_init(&s, type, len);
672 			seq_buf_puts(&s, "__data_loc ");
673 			seq_buf_puts(&s, field->type);
674 
675 			if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
676 				goto free;
677 			s.buffer[s.len] = '\0';
678 
679 			kfree(field->type);
680 			field->type = type;
681 
682 			field->is_dynamic = true;
683 			size = sizeof(u64);
684 		} else {
685 			synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
686 			ret = -EINVAL;
687 			goto free;
688 		}
689 	}
690 	field->size = size;
691 
692 	if (synth_field_is_string(field->type))
693 		field->is_string = true;
694 
695 	field->is_signed = synth_field_signed(field->type);
696  out:
697 	return field;
698  free:
699 	free_synth_field(field);
700 	field = ERR_PTR(ret);
701 	goto out;
702 }
703 
704 static void free_synth_tracepoint(struct tracepoint *tp)
705 {
706 	if (!tp)
707 		return;
708 
709 	kfree(tp->name);
710 	kfree(tp);
711 }
712 
713 static struct tracepoint *alloc_synth_tracepoint(char *name)
714 {
715 	struct tracepoint *tp;
716 
717 	tp = kzalloc(sizeof(*tp), GFP_KERNEL);
718 	if (!tp)
719 		return ERR_PTR(-ENOMEM);
720 
721 	tp->name = kstrdup(name, GFP_KERNEL);
722 	if (!tp->name) {
723 		kfree(tp);
724 		return ERR_PTR(-ENOMEM);
725 	}
726 
727 	return tp;
728 }
729 
730 struct synth_event *find_synth_event(const char *name)
731 {
732 	struct dyn_event *pos;
733 	struct synth_event *event;
734 
735 	for_each_dyn_event(pos) {
736 		if (!is_synth_event(pos))
737 			continue;
738 		event = to_synth_event(pos);
739 		if (strcmp(event->name, name) == 0)
740 			return event;
741 	}
742 
743 	return NULL;
744 }
745 
746 static struct trace_event_fields synth_event_fields_array[] = {
747 	{ .type = TRACE_FUNCTION_TYPE,
748 	  .define_fields = synth_event_define_fields },
749 	{}
750 };
751 
752 static int register_synth_event(struct synth_event *event)
753 {
754 	struct trace_event_call *call = &event->call;
755 	int ret = 0;
756 
757 	event->call.class = &event->class;
758 	event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
759 	if (!event->class.system) {
760 		ret = -ENOMEM;
761 		goto out;
762 	}
763 
764 	event->tp = alloc_synth_tracepoint(event->name);
765 	if (IS_ERR(event->tp)) {
766 		ret = PTR_ERR(event->tp);
767 		event->tp = NULL;
768 		goto out;
769 	}
770 
771 	INIT_LIST_HEAD(&call->class->fields);
772 	call->event.funcs = &synth_event_funcs;
773 	call->class->fields_array = synth_event_fields_array;
774 
775 	ret = register_trace_event(&call->event);
776 	if (!ret) {
777 		ret = -ENODEV;
778 		goto out;
779 	}
780 	call->flags = TRACE_EVENT_FL_TRACEPOINT;
781 	call->class->reg = trace_event_reg;
782 	call->class->probe = trace_event_raw_event_synth;
783 	call->data = event;
784 	call->tp = event->tp;
785 
786 	ret = trace_add_event_call(call);
787 	if (ret) {
788 		pr_warn("Failed to register synthetic event: %s\n",
789 			trace_event_name(call));
790 		goto err;
791 	}
792 
793 	ret = set_synth_event_print_fmt(call);
794 	if (ret < 0) {
795 		trace_remove_event_call(call);
796 		goto err;
797 	}
798  out:
799 	return ret;
800  err:
801 	unregister_trace_event(&call->event);
802 	goto out;
803 }
804 
805 static int unregister_synth_event(struct synth_event *event)
806 {
807 	struct trace_event_call *call = &event->call;
808 	int ret;
809 
810 	ret = trace_remove_event_call(call);
811 
812 	return ret;
813 }
814 
815 static void free_synth_event(struct synth_event *event)
816 {
817 	unsigned int i;
818 
819 	if (!event)
820 		return;
821 
822 	for (i = 0; i < event->n_fields; i++)
823 		free_synth_field(event->fields[i]);
824 
825 	kfree(event->fields);
826 	kfree(event->dynamic_fields);
827 	kfree(event->name);
828 	kfree(event->class.system);
829 	free_synth_tracepoint(event->tp);
830 	free_synth_event_print_fmt(&event->call);
831 	kfree(event);
832 }
833 
834 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
835 					     struct synth_field **fields)
836 {
837 	unsigned int i, j, n_dynamic_fields = 0;
838 	struct synth_event *event;
839 
840 	event = kzalloc(sizeof(*event), GFP_KERNEL);
841 	if (!event) {
842 		event = ERR_PTR(-ENOMEM);
843 		goto out;
844 	}
845 
846 	event->name = kstrdup(name, GFP_KERNEL);
847 	if (!event->name) {
848 		kfree(event);
849 		event = ERR_PTR(-ENOMEM);
850 		goto out;
851 	}
852 
853 	event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
854 	if (!event->fields) {
855 		free_synth_event(event);
856 		event = ERR_PTR(-ENOMEM);
857 		goto out;
858 	}
859 
860 	for (i = 0; i < n_fields; i++)
861 		if (fields[i]->is_dynamic)
862 			n_dynamic_fields++;
863 
864 	if (n_dynamic_fields) {
865 		event->dynamic_fields = kcalloc(n_dynamic_fields,
866 						sizeof(*event->dynamic_fields),
867 						GFP_KERNEL);
868 		if (!event->dynamic_fields) {
869 			free_synth_event(event);
870 			event = ERR_PTR(-ENOMEM);
871 			goto out;
872 		}
873 	}
874 
875 	dyn_event_init(&event->devent, &synth_event_ops);
876 
877 	for (i = 0, j = 0; i < n_fields; i++) {
878 		event->fields[i] = fields[i];
879 
880 		if (fields[i]->is_dynamic) {
881 			event->dynamic_fields[j] = fields[i];
882 			event->dynamic_fields[j]->field_pos = i;
883 			event->dynamic_fields[j++] = fields[i];
884 			event->n_dynamic_fields++;
885 		}
886 	}
887 	event->n_fields = n_fields;
888  out:
889 	return event;
890 }
891 
892 static int synth_event_check_arg_fn(void *data)
893 {
894 	struct dynevent_arg_pair *arg_pair = data;
895 	int size;
896 
897 	size = synth_field_size((char *)arg_pair->lhs);
898 	if (size == 0) {
899 		if (strstr((char *)arg_pair->lhs, "["))
900 			return 0;
901 	}
902 
903 	return size ? 0 : -EINVAL;
904 }
905 
906 /**
907  * synth_event_add_field - Add a new field to a synthetic event cmd
908  * @cmd: A pointer to the dynevent_cmd struct representing the new event
909  * @type: The type of the new field to add
910  * @name: The name of the new field to add
911  *
912  * Add a new field to a synthetic event cmd object.  Field ordering is in
913  * the same order the fields are added.
914  *
915  * See synth_field_size() for available types. If field_name contains
916  * [n] the field is considered to be an array.
917  *
918  * Return: 0 if successful, error otherwise.
919  */
920 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
921 			  const char *name)
922 {
923 	struct dynevent_arg_pair arg_pair;
924 	int ret;
925 
926 	if (cmd->type != DYNEVENT_TYPE_SYNTH)
927 		return -EINVAL;
928 
929 	if (!type || !name)
930 		return -EINVAL;
931 
932 	dynevent_arg_pair_init(&arg_pair, 0, ';');
933 
934 	arg_pair.lhs = type;
935 	arg_pair.rhs = name;
936 
937 	ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
938 	if (ret)
939 		return ret;
940 
941 	if (++cmd->n_fields > SYNTH_FIELDS_MAX)
942 		ret = -EINVAL;
943 
944 	return ret;
945 }
946 EXPORT_SYMBOL_GPL(synth_event_add_field);
947 
948 /**
949  * synth_event_add_field_str - Add a new field to a synthetic event cmd
950  * @cmd: A pointer to the dynevent_cmd struct representing the new event
951  * @type_name: The type and name of the new field to add, as a single string
952  *
953  * Add a new field to a synthetic event cmd object, as a single
954  * string.  The @type_name string is expected to be of the form 'type
955  * name', which will be appended by ';'.  No sanity checking is done -
956  * what's passed in is assumed to already be well-formed.  Field
957  * ordering is in the same order the fields are added.
958  *
959  * See synth_field_size() for available types. If field_name contains
960  * [n] the field is considered to be an array.
961  *
962  * Return: 0 if successful, error otherwise.
963  */
964 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
965 {
966 	struct dynevent_arg arg;
967 	int ret;
968 
969 	if (cmd->type != DYNEVENT_TYPE_SYNTH)
970 		return -EINVAL;
971 
972 	if (!type_name)
973 		return -EINVAL;
974 
975 	dynevent_arg_init(&arg, ';');
976 
977 	arg.str = type_name;
978 
979 	ret = dynevent_arg_add(cmd, &arg, NULL);
980 	if (ret)
981 		return ret;
982 
983 	if (++cmd->n_fields > SYNTH_FIELDS_MAX)
984 		ret = -EINVAL;
985 
986 	return ret;
987 }
988 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
989 
990 /**
991  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
992  * @cmd: A pointer to the dynevent_cmd struct representing the new event
993  * @fields: An array of type/name field descriptions
994  * @n_fields: The number of field descriptions contained in the fields array
995  *
996  * Add a new set of fields to a synthetic event cmd object.  The event
997  * fields that will be defined for the event should be passed in as an
998  * array of struct synth_field_desc, and the number of elements in the
999  * array passed in as n_fields.  Field ordering will retain the
1000  * ordering given in the fields array.
1001  *
1002  * See synth_field_size() for available types. If field_name contains
1003  * [n] the field is considered to be an array.
1004  *
1005  * Return: 0 if successful, error otherwise.
1006  */
1007 int synth_event_add_fields(struct dynevent_cmd *cmd,
1008 			   struct synth_field_desc *fields,
1009 			   unsigned int n_fields)
1010 {
1011 	unsigned int i;
1012 	int ret = 0;
1013 
1014 	for (i = 0; i < n_fields; i++) {
1015 		if (fields[i].type == NULL || fields[i].name == NULL) {
1016 			ret = -EINVAL;
1017 			break;
1018 		}
1019 
1020 		ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1021 		if (ret)
1022 			break;
1023 	}
1024 
1025 	return ret;
1026 }
1027 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1028 
1029 /**
1030  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1031  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1032  * @name: The name of the synthetic event
1033  * @mod: The module creating the event, NULL if not created from a module
1034  * @args: Variable number of arg (pairs), one pair for each field
1035  *
1036  * NOTE: Users normally won't want to call this function directly, but
1037  * rather use the synth_event_gen_cmd_start() wrapper, which
1038  * automatically adds a NULL to the end of the arg list.  If this
1039  * function is used directly, make sure the last arg in the variable
1040  * arg list is NULL.
1041  *
1042  * Generate a synthetic event command to be executed by
1043  * synth_event_gen_cmd_end().  This function can be used to generate
1044  * the complete command or only the first part of it; in the latter
1045  * case, synth_event_add_field(), synth_event_add_field_str(), or
1046  * synth_event_add_fields() can be used to add more fields following
1047  * this.
1048  *
1049  * There should be an even number variable args, each pair consisting
1050  * of a type followed by a field name.
1051  *
1052  * See synth_field_size() for available types. If field_name contains
1053  * [n] the field is considered to be an array.
1054  *
1055  * Return: 0 if successful, error otherwise.
1056  */
1057 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1058 				struct module *mod, ...)
1059 {
1060 	struct dynevent_arg arg;
1061 	va_list args;
1062 	int ret;
1063 
1064 	cmd->event_name = name;
1065 	cmd->private_data = mod;
1066 
1067 	if (cmd->type != DYNEVENT_TYPE_SYNTH)
1068 		return -EINVAL;
1069 
1070 	dynevent_arg_init(&arg, 0);
1071 	arg.str = name;
1072 	ret = dynevent_arg_add(cmd, &arg, NULL);
1073 	if (ret)
1074 		return ret;
1075 
1076 	va_start(args, mod);
1077 	for (;;) {
1078 		const char *type, *name;
1079 
1080 		type = va_arg(args, const char *);
1081 		if (!type)
1082 			break;
1083 		name = va_arg(args, const char *);
1084 		if (!name)
1085 			break;
1086 
1087 		if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1088 			ret = -EINVAL;
1089 			break;
1090 		}
1091 
1092 		ret = synth_event_add_field(cmd, type, name);
1093 		if (ret)
1094 			break;
1095 	}
1096 	va_end(args);
1097 
1098 	return ret;
1099 }
1100 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1101 
1102 /**
1103  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1104  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1105  * @name: The name of the synthetic event
1106  * @fields: An array of type/name field descriptions
1107  * @n_fields: The number of field descriptions contained in the fields array
1108  *
1109  * Generate a synthetic event command to be executed by
1110  * synth_event_gen_cmd_end().  This function can be used to generate
1111  * the complete command or only the first part of it; in the latter
1112  * case, synth_event_add_field(), synth_event_add_field_str(), or
1113  * synth_event_add_fields() can be used to add more fields following
1114  * this.
1115  *
1116  * The event fields that will be defined for the event should be
1117  * passed in as an array of struct synth_field_desc, and the number of
1118  * elements in the array passed in as n_fields.  Field ordering will
1119  * retain the ordering given in the fields array.
1120  *
1121  * See synth_field_size() for available types. If field_name contains
1122  * [n] the field is considered to be an array.
1123  *
1124  * Return: 0 if successful, error otherwise.
1125  */
1126 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1127 				    struct module *mod,
1128 				    struct synth_field_desc *fields,
1129 				    unsigned int n_fields)
1130 {
1131 	struct dynevent_arg arg;
1132 	unsigned int i;
1133 	int ret = 0;
1134 
1135 	cmd->event_name = name;
1136 	cmd->private_data = mod;
1137 
1138 	if (cmd->type != DYNEVENT_TYPE_SYNTH)
1139 		return -EINVAL;
1140 
1141 	if (n_fields > SYNTH_FIELDS_MAX)
1142 		return -EINVAL;
1143 
1144 	dynevent_arg_init(&arg, 0);
1145 	arg.str = name;
1146 	ret = dynevent_arg_add(cmd, &arg, NULL);
1147 	if (ret)
1148 		return ret;
1149 
1150 	for (i = 0; i < n_fields; i++) {
1151 		if (fields[i].type == NULL || fields[i].name == NULL)
1152 			return -EINVAL;
1153 
1154 		ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1155 		if (ret)
1156 			break;
1157 	}
1158 
1159 	return ret;
1160 }
1161 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1162 
1163 static int save_cmdstr(int argc, const char *name, const char **argv)
1164 {
1165 	struct seq_buf s;
1166 	char *buf;
1167 	int i;
1168 
1169 	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1170 	if (!buf)
1171 		return -ENOMEM;
1172 
1173 	seq_buf_init(&s, buf, MAX_DYNEVENT_CMD_LEN);
1174 
1175 	seq_buf_puts(&s, name);
1176 
1177 	for (i = 0; i < argc; i++) {
1178 		seq_buf_putc(&s, ' ');
1179 		seq_buf_puts(&s, argv[i]);
1180 	}
1181 
1182 	if (!seq_buf_buffer_left(&s)) {
1183 		synth_err(SYNTH_ERR_CMD_TOO_LONG, 0);
1184 		kfree(buf);
1185 		return -EINVAL;
1186 	}
1187 	buf[s.len] = 0;
1188 	last_cmd_set(buf);
1189 
1190 	kfree(buf);
1191 	return 0;
1192 }
1193 
1194 static int __create_synth_event(int argc, const char *name, const char **argv)
1195 {
1196 	struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1197 	struct synth_event *event = NULL;
1198 	int i, consumed = 0, n_fields = 0, ret = 0;
1199 
1200 	ret = save_cmdstr(argc, name, argv);
1201 	if (ret)
1202 		return ret;
1203 
1204 	/*
1205 	 * Argument syntax:
1206 	 *  - Add synthetic event: <event_name> field[;field] ...
1207 	 *  - Remove synthetic event: !<event_name> field[;field] ...
1208 	 *      where 'field' = type field_name
1209 	 */
1210 
1211 	if (name[0] == '\0' || argc < 1) {
1212 		synth_err(SYNTH_ERR_CMD_INCOMPLETE, 0);
1213 		return -EINVAL;
1214 	}
1215 
1216 	mutex_lock(&event_mutex);
1217 
1218 	if (!is_good_name(name)) {
1219 		synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1220 		ret = -EINVAL;
1221 		goto out;
1222 	}
1223 
1224 	event = find_synth_event(name);
1225 	if (event) {
1226 		synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1227 		ret = -EEXIST;
1228 		goto out;
1229 	}
1230 
1231 	for (i = 0; i < argc - 1; i++) {
1232 		if (strcmp(argv[i], ";") == 0)
1233 			continue;
1234 		if (n_fields == SYNTH_FIELDS_MAX) {
1235 			synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1236 			ret = -EINVAL;
1237 			goto err;
1238 		}
1239 
1240 		field = parse_synth_field(argc - i, &argv[i], &consumed);
1241 		if (IS_ERR(field)) {
1242 			ret = PTR_ERR(field);
1243 			goto err;
1244 		}
1245 		fields[n_fields++] = field;
1246 		i += consumed - 1;
1247 	}
1248 
1249 	if (i < argc && strcmp(argv[i], ";") != 0) {
1250 		synth_err(SYNTH_ERR_INVALID_FIELD, errpos(argv[i]));
1251 		ret = -EINVAL;
1252 		goto err;
1253 	}
1254 
1255 	event = alloc_synth_event(name, n_fields, fields);
1256 	if (IS_ERR(event)) {
1257 		ret = PTR_ERR(event);
1258 		event = NULL;
1259 		goto err;
1260 	}
1261 	ret = register_synth_event(event);
1262 	if (!ret)
1263 		dyn_event_add(&event->devent);
1264 	else
1265 		free_synth_event(event);
1266  out:
1267 	mutex_unlock(&event_mutex);
1268 
1269 	return ret;
1270  err:
1271 	for (i = 0; i < n_fields; i++)
1272 		free_synth_field(fields[i]);
1273 
1274 	goto out;
1275 }
1276 
1277 /**
1278  * synth_event_create - Create a new synthetic event
1279  * @name: The name of the new synthetic event
1280  * @fields: An array of type/name field descriptions
1281  * @n_fields: The number of field descriptions contained in the fields array
1282  * @mod: The module creating the event, NULL if not created from a module
1283  *
1284  * Create a new synthetic event with the given name under the
1285  * trace/events/synthetic/ directory.  The event fields that will be
1286  * defined for the event should be passed in as an array of struct
1287  * synth_field_desc, and the number elements in the array passed in as
1288  * n_fields. Field ordering will retain the ordering given in the
1289  * fields array.
1290  *
1291  * If the new synthetic event is being created from a module, the mod
1292  * param must be non-NULL.  This will ensure that the trace buffer
1293  * won't contain unreadable events.
1294  *
1295  * The new synth event should be deleted using synth_event_delete()
1296  * function.  The new synthetic event can be generated from modules or
1297  * other kernel code using trace_synth_event() and related functions.
1298  *
1299  * Return: 0 if successful, error otherwise.
1300  */
1301 int synth_event_create(const char *name, struct synth_field_desc *fields,
1302 		       unsigned int n_fields, struct module *mod)
1303 {
1304 	struct dynevent_cmd cmd;
1305 	char *buf;
1306 	int ret;
1307 
1308 	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1309 	if (!buf)
1310 		return -ENOMEM;
1311 
1312 	synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1313 
1314 	ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1315 					      fields, n_fields);
1316 	if (ret)
1317 		goto out;
1318 
1319 	ret = synth_event_gen_cmd_end(&cmd);
1320  out:
1321 	kfree(buf);
1322 
1323 	return ret;
1324 }
1325 EXPORT_SYMBOL_GPL(synth_event_create);
1326 
1327 static int destroy_synth_event(struct synth_event *se)
1328 {
1329 	int ret;
1330 
1331 	if (se->ref)
1332 		ret = -EBUSY;
1333 	else {
1334 		ret = unregister_synth_event(se);
1335 		if (!ret) {
1336 			dyn_event_remove(&se->devent);
1337 			free_synth_event(se);
1338 		}
1339 	}
1340 
1341 	return ret;
1342 }
1343 
1344 /**
1345  * synth_event_delete - Delete a synthetic event
1346  * @event_name: The name of the new sythetic event
1347  *
1348  * Delete a synthetic event that was created with synth_event_create().
1349  *
1350  * Return: 0 if successful, error otherwise.
1351  */
1352 int synth_event_delete(const char *event_name)
1353 {
1354 	struct synth_event *se = NULL;
1355 	struct module *mod = NULL;
1356 	int ret = -ENOENT;
1357 
1358 	mutex_lock(&event_mutex);
1359 	se = find_synth_event(event_name);
1360 	if (se) {
1361 		mod = se->mod;
1362 		ret = destroy_synth_event(se);
1363 	}
1364 	mutex_unlock(&event_mutex);
1365 
1366 	if (mod) {
1367 		mutex_lock(&trace_types_lock);
1368 		/*
1369 		 * It is safest to reset the ring buffer if the module
1370 		 * being unloaded registered any events that were
1371 		 * used. The only worry is if a new module gets
1372 		 * loaded, and takes on the same id as the events of
1373 		 * this module. When printing out the buffer, traced
1374 		 * events left over from this module may be passed to
1375 		 * the new module events and unexpected results may
1376 		 * occur.
1377 		 */
1378 		tracing_reset_all_online_cpus();
1379 		mutex_unlock(&trace_types_lock);
1380 	}
1381 
1382 	return ret;
1383 }
1384 EXPORT_SYMBOL_GPL(synth_event_delete);
1385 
1386 static int create_or_delete_synth_event(int argc, char **argv)
1387 {
1388 	const char *name = argv[0];
1389 	int ret;
1390 
1391 	/* trace_run_command() ensures argc != 0 */
1392 	if (name[0] == '!') {
1393 		ret = synth_event_delete(name + 1);
1394 		return ret;
1395 	}
1396 
1397 	ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
1398 	return ret == -ECANCELED ? -EINVAL : ret;
1399 }
1400 
1401 static int synth_event_run_command(struct dynevent_cmd *cmd)
1402 {
1403 	struct synth_event *se;
1404 	int ret;
1405 
1406 	ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
1407 	if (ret)
1408 		return ret;
1409 
1410 	se = find_synth_event(cmd->event_name);
1411 	if (WARN_ON(!se))
1412 		return -ENOENT;
1413 
1414 	se->mod = cmd->private_data;
1415 
1416 	return ret;
1417 }
1418 
1419 /**
1420  * synth_event_cmd_init - Initialize a synthetic event command object
1421  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1422  * @buf: A pointer to the buffer used to build the command
1423  * @maxlen: The length of the buffer passed in @buf
1424  *
1425  * Initialize a synthetic event command object.  Use this before
1426  * calling any of the other dyenvent_cmd functions.
1427  */
1428 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1429 {
1430 	dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1431 			  synth_event_run_command);
1432 }
1433 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1434 
1435 static inline int
1436 __synth_event_trace_init(struct trace_event_file *file,
1437 			 struct synth_event_trace_state *trace_state)
1438 {
1439 	int ret = 0;
1440 
1441 	memset(trace_state, '\0', sizeof(*trace_state));
1442 
1443 	/*
1444 	 * Normal event tracing doesn't get called at all unless the
1445 	 * ENABLED bit is set (which attaches the probe thus allowing
1446 	 * this code to be called, etc).  Because this is called
1447 	 * directly by the user, we don't have that but we still need
1448 	 * to honor not logging when disabled.  For the iterated
1449 	 * trace case, we save the enabled state upon start and just
1450 	 * ignore the following data calls.
1451 	 */
1452 	if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1453 	    trace_trigger_soft_disabled(file)) {
1454 		trace_state->disabled = true;
1455 		ret = -ENOENT;
1456 		goto out;
1457 	}
1458 
1459 	trace_state->event = file->event_call->data;
1460 out:
1461 	return ret;
1462 }
1463 
1464 static inline int
1465 __synth_event_trace_start(struct trace_event_file *file,
1466 			  struct synth_event_trace_state *trace_state,
1467 			  int dynamic_fields_size)
1468 {
1469 	int entry_size, fields_size = 0;
1470 	int ret = 0;
1471 
1472 	fields_size = trace_state->event->n_u64 * sizeof(u64);
1473 	fields_size += dynamic_fields_size;
1474 
1475 	/*
1476 	 * Avoid ring buffer recursion detection, as this event
1477 	 * is being performed within another event.
1478 	 */
1479 	trace_state->buffer = file->tr->array_buffer.buffer;
1480 	ring_buffer_nest_start(trace_state->buffer);
1481 
1482 	entry_size = sizeof(*trace_state->entry) + fields_size;
1483 	trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1484 							file,
1485 							entry_size);
1486 	if (!trace_state->entry) {
1487 		ring_buffer_nest_end(trace_state->buffer);
1488 		ret = -EINVAL;
1489 	}
1490 
1491 	return ret;
1492 }
1493 
1494 static inline void
1495 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1496 {
1497 	trace_event_buffer_commit(&trace_state->fbuffer);
1498 
1499 	ring_buffer_nest_end(trace_state->buffer);
1500 }
1501 
1502 /**
1503  * synth_event_trace - Trace a synthetic event
1504  * @file: The trace_event_file representing the synthetic event
1505  * @n_vals: The number of values in vals
1506  * @args: Variable number of args containing the event values
1507  *
1508  * Trace a synthetic event using the values passed in the variable
1509  * argument list.
1510  *
1511  * The argument list should be a list 'n_vals' u64 values.  The number
1512  * of vals must match the number of field in the synthetic event, and
1513  * must be in the same order as the synthetic event fields.
1514  *
1515  * All vals should be cast to u64, and string vals are just pointers
1516  * to strings, cast to u64.  Strings will be copied into space
1517  * reserved in the event for the string, using these pointers.
1518  *
1519  * Return: 0 on success, err otherwise.
1520  */
1521 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1522 {
1523 	unsigned int i, n_u64, len, data_size = 0;
1524 	struct synth_event_trace_state state;
1525 	va_list args;
1526 	int ret;
1527 
1528 	ret = __synth_event_trace_init(file, &state);
1529 	if (ret) {
1530 		if (ret == -ENOENT)
1531 			ret = 0; /* just disabled, not really an error */
1532 		return ret;
1533 	}
1534 
1535 	if (state.event->n_dynamic_fields) {
1536 		va_start(args, n_vals);
1537 
1538 		for (i = 0; i < state.event->n_fields; i++) {
1539 			u64 val = va_arg(args, u64);
1540 
1541 			if (state.event->fields[i]->is_string &&
1542 			    state.event->fields[i]->is_dynamic) {
1543 				char *str_val = (char *)(long)val;
1544 
1545 				data_size += strlen(str_val) + 1;
1546 			}
1547 		}
1548 
1549 		va_end(args);
1550 	}
1551 
1552 	ret = __synth_event_trace_start(file, &state, data_size);
1553 	if (ret)
1554 		return ret;
1555 
1556 	if (n_vals != state.event->n_fields) {
1557 		ret = -EINVAL;
1558 		goto out;
1559 	}
1560 
1561 	data_size = 0;
1562 
1563 	va_start(args, n_vals);
1564 	for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1565 		u64 val;
1566 
1567 		val = va_arg(args, u64);
1568 
1569 		if (state.event->fields[i]->is_string) {
1570 			char *str_val = (char *)(long)val;
1571 
1572 			len = trace_string(state.entry, state.event, str_val,
1573 					   state.event->fields[i]->is_dynamic,
1574 					   data_size, &n_u64);
1575 			data_size += len; /* only dynamic string increments */
1576 		} else {
1577 			struct synth_field *field = state.event->fields[i];
1578 
1579 			switch (field->size) {
1580 			case 1:
1581 				*(u8 *)&state.entry->fields[n_u64] = (u8)val;
1582 				break;
1583 
1584 			case 2:
1585 				*(u16 *)&state.entry->fields[n_u64] = (u16)val;
1586 				break;
1587 
1588 			case 4:
1589 				*(u32 *)&state.entry->fields[n_u64] = (u32)val;
1590 				break;
1591 
1592 			default:
1593 				state.entry->fields[n_u64] = val;
1594 				break;
1595 			}
1596 			n_u64++;
1597 		}
1598 	}
1599 	va_end(args);
1600 out:
1601 	__synth_event_trace_end(&state);
1602 
1603 	return ret;
1604 }
1605 EXPORT_SYMBOL_GPL(synth_event_trace);
1606 
1607 /**
1608  * synth_event_trace_array - Trace a synthetic event from an array
1609  * @file: The trace_event_file representing the synthetic event
1610  * @vals: Array of values
1611  * @n_vals: The number of values in vals
1612  *
1613  * Trace a synthetic event using the values passed in as 'vals'.
1614  *
1615  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1616  * vals must match the number of field in the synthetic event, and
1617  * must be in the same order as the synthetic event fields.
1618  *
1619  * All vals should be cast to u64, and string vals are just pointers
1620  * to strings, cast to u64.  Strings will be copied into space
1621  * reserved in the event for the string, using these pointers.
1622  *
1623  * Return: 0 on success, err otherwise.
1624  */
1625 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1626 			    unsigned int n_vals)
1627 {
1628 	unsigned int i, n_u64, field_pos, len, data_size = 0;
1629 	struct synth_event_trace_state state;
1630 	char *str_val;
1631 	int ret;
1632 
1633 	ret = __synth_event_trace_init(file, &state);
1634 	if (ret) {
1635 		if (ret == -ENOENT)
1636 			ret = 0; /* just disabled, not really an error */
1637 		return ret;
1638 	}
1639 
1640 	if (state.event->n_dynamic_fields) {
1641 		for (i = 0; i < state.event->n_dynamic_fields; i++) {
1642 			field_pos = state.event->dynamic_fields[i]->field_pos;
1643 			str_val = (char *)(long)vals[field_pos];
1644 			len = strlen(str_val) + 1;
1645 			data_size += len;
1646 		}
1647 	}
1648 
1649 	ret = __synth_event_trace_start(file, &state, data_size);
1650 	if (ret)
1651 		return ret;
1652 
1653 	if (n_vals != state.event->n_fields) {
1654 		ret = -EINVAL;
1655 		goto out;
1656 	}
1657 
1658 	data_size = 0;
1659 
1660 	for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1661 		if (state.event->fields[i]->is_string) {
1662 			char *str_val = (char *)(long)vals[i];
1663 
1664 			len = trace_string(state.entry, state.event, str_val,
1665 					   state.event->fields[i]->is_dynamic,
1666 					   data_size, &n_u64);
1667 			data_size += len; /* only dynamic string increments */
1668 		} else {
1669 			struct synth_field *field = state.event->fields[i];
1670 			u64 val = vals[i];
1671 
1672 			switch (field->size) {
1673 			case 1:
1674 				*(u8 *)&state.entry->fields[n_u64] = (u8)val;
1675 				break;
1676 
1677 			case 2:
1678 				*(u16 *)&state.entry->fields[n_u64] = (u16)val;
1679 				break;
1680 
1681 			case 4:
1682 				*(u32 *)&state.entry->fields[n_u64] = (u32)val;
1683 				break;
1684 
1685 			default:
1686 				state.entry->fields[n_u64] = val;
1687 				break;
1688 			}
1689 			n_u64++;
1690 		}
1691 	}
1692 out:
1693 	__synth_event_trace_end(&state);
1694 
1695 	return ret;
1696 }
1697 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1698 
1699 /**
1700  * synth_event_trace_start - Start piecewise synthetic event trace
1701  * @file: The trace_event_file representing the synthetic event
1702  * @trace_state: A pointer to object tracking the piecewise trace state
1703  *
1704  * Start the trace of a synthetic event field-by-field rather than all
1705  * at once.
1706  *
1707  * This function 'opens' an event trace, which means space is reserved
1708  * for the event in the trace buffer, after which the event's
1709  * individual field values can be set through either
1710  * synth_event_add_next_val() or synth_event_add_val().
1711  *
1712  * A pointer to a trace_state object is passed in, which will keep
1713  * track of the current event trace state until the event trace is
1714  * closed (and the event finally traced) using
1715  * synth_event_trace_end().
1716  *
1717  * Note that synth_event_trace_end() must be called after all values
1718  * have been added for each event trace, regardless of whether adding
1719  * all field values succeeded or not.
1720  *
1721  * Note also that for a given event trace, all fields must be added
1722  * using either synth_event_add_next_val() or synth_event_add_val()
1723  * but not both together or interleaved.
1724  *
1725  * Return: 0 on success, err otherwise.
1726  */
1727 int synth_event_trace_start(struct trace_event_file *file,
1728 			    struct synth_event_trace_state *trace_state)
1729 {
1730 	int ret;
1731 
1732 	if (!trace_state)
1733 		return -EINVAL;
1734 
1735 	ret = __synth_event_trace_init(file, trace_state);
1736 	if (ret) {
1737 		if (ret == -ENOENT)
1738 			ret = 0; /* just disabled, not really an error */
1739 		return ret;
1740 	}
1741 
1742 	if (trace_state->event->n_dynamic_fields)
1743 		return -ENOTSUPP;
1744 
1745 	ret = __synth_event_trace_start(file, trace_state, 0);
1746 
1747 	return ret;
1748 }
1749 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1750 
1751 static int __synth_event_add_val(const char *field_name, u64 val,
1752 				 struct synth_event_trace_state *trace_state)
1753 {
1754 	struct synth_field *field = NULL;
1755 	struct synth_trace_event *entry;
1756 	struct synth_event *event;
1757 	int i, ret = 0;
1758 
1759 	if (!trace_state) {
1760 		ret = -EINVAL;
1761 		goto out;
1762 	}
1763 
1764 	/* can't mix add_next_synth_val() with add_synth_val() */
1765 	if (field_name) {
1766 		if (trace_state->add_next) {
1767 			ret = -EINVAL;
1768 			goto out;
1769 		}
1770 		trace_state->add_name = true;
1771 	} else {
1772 		if (trace_state->add_name) {
1773 			ret = -EINVAL;
1774 			goto out;
1775 		}
1776 		trace_state->add_next = true;
1777 	}
1778 
1779 	if (trace_state->disabled)
1780 		goto out;
1781 
1782 	event = trace_state->event;
1783 	if (trace_state->add_name) {
1784 		for (i = 0; i < event->n_fields; i++) {
1785 			field = event->fields[i];
1786 			if (strcmp(field->name, field_name) == 0)
1787 				break;
1788 		}
1789 		if (!field) {
1790 			ret = -EINVAL;
1791 			goto out;
1792 		}
1793 	} else {
1794 		if (trace_state->cur_field >= event->n_fields) {
1795 			ret = -EINVAL;
1796 			goto out;
1797 		}
1798 		field = event->fields[trace_state->cur_field++];
1799 	}
1800 
1801 	entry = trace_state->entry;
1802 	if (field->is_string) {
1803 		char *str_val = (char *)(long)val;
1804 		char *str_field;
1805 
1806 		if (field->is_dynamic) { /* add_val can't do dynamic strings */
1807 			ret = -EINVAL;
1808 			goto out;
1809 		}
1810 
1811 		if (!str_val) {
1812 			ret = -EINVAL;
1813 			goto out;
1814 		}
1815 
1816 		str_field = (char *)&entry->fields[field->offset];
1817 		strscpy(str_field, str_val, STR_VAR_LEN_MAX);
1818 	} else {
1819 		switch (field->size) {
1820 		case 1:
1821 			*(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
1822 			break;
1823 
1824 		case 2:
1825 			*(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
1826 			break;
1827 
1828 		case 4:
1829 			*(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
1830 			break;
1831 
1832 		default:
1833 			trace_state->entry->fields[field->offset] = val;
1834 			break;
1835 		}
1836 	}
1837  out:
1838 	return ret;
1839 }
1840 
1841 /**
1842  * synth_event_add_next_val - Add the next field's value to an open synth trace
1843  * @val: The value to set the next field to
1844  * @trace_state: A pointer to object tracking the piecewise trace state
1845  *
1846  * Set the value of the next field in an event that's been opened by
1847  * synth_event_trace_start().
1848  *
1849  * The val param should be the value cast to u64.  If the value points
1850  * to a string, the val param should be a char * cast to u64.
1851  *
1852  * This function assumes all the fields in an event are to be set one
1853  * after another - successive calls to this function are made, one for
1854  * each field, in the order of the fields in the event, until all
1855  * fields have been set.  If you'd rather set each field individually
1856  * without regard to ordering, synth_event_add_val() can be used
1857  * instead.
1858  *
1859  * Note however that synth_event_add_next_val() and
1860  * synth_event_add_val() can't be intermixed for a given event trace -
1861  * one or the other but not both can be used at the same time.
1862  *
1863  * Note also that synth_event_trace_end() must be called after all
1864  * values have been added for each event trace, regardless of whether
1865  * adding all field values succeeded or not.
1866  *
1867  * Return: 0 on success, err otherwise.
1868  */
1869 int synth_event_add_next_val(u64 val,
1870 			     struct synth_event_trace_state *trace_state)
1871 {
1872 	return __synth_event_add_val(NULL, val, trace_state);
1873 }
1874 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
1875 
1876 /**
1877  * synth_event_add_val - Add a named field's value to an open synth trace
1878  * @field_name: The name of the synthetic event field value to set
1879  * @val: The value to set the next field to
1880  * @trace_state: A pointer to object tracking the piecewise trace state
1881  *
1882  * Set the value of the named field in an event that's been opened by
1883  * synth_event_trace_start().
1884  *
1885  * The val param should be the value cast to u64.  If the value points
1886  * to a string, the val param should be a char * cast to u64.
1887  *
1888  * This function looks up the field name, and if found, sets the field
1889  * to the specified value.  This lookup makes this function more
1890  * expensive than synth_event_add_next_val(), so use that or the
1891  * none-piecewise synth_event_trace() instead if efficiency is more
1892  * important.
1893  *
1894  * Note however that synth_event_add_next_val() and
1895  * synth_event_add_val() can't be intermixed for a given event trace -
1896  * one or the other but not both can be used at the same time.
1897  *
1898  * Note also that synth_event_trace_end() must be called after all
1899  * values have been added for each event trace, regardless of whether
1900  * adding all field values succeeded or not.
1901  *
1902  * Return: 0 on success, err otherwise.
1903  */
1904 int synth_event_add_val(const char *field_name, u64 val,
1905 			struct synth_event_trace_state *trace_state)
1906 {
1907 	return __synth_event_add_val(field_name, val, trace_state);
1908 }
1909 EXPORT_SYMBOL_GPL(synth_event_add_val);
1910 
1911 /**
1912  * synth_event_trace_end - End piecewise synthetic event trace
1913  * @trace_state: A pointer to object tracking the piecewise trace state
1914  *
1915  * End the trace of a synthetic event opened by
1916  * synth_event_trace__start().
1917  *
1918  * This function 'closes' an event trace, which basically means that
1919  * it commits the reserved event and cleans up other loose ends.
1920  *
1921  * A pointer to a trace_state object is passed in, which will keep
1922  * track of the current event trace state opened with
1923  * synth_event_trace_start().
1924  *
1925  * Note that this function must be called after all values have been
1926  * added for each event trace, regardless of whether adding all field
1927  * values succeeded or not.
1928  *
1929  * Return: 0 on success, err otherwise.
1930  */
1931 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
1932 {
1933 	if (!trace_state)
1934 		return -EINVAL;
1935 
1936 	__synth_event_trace_end(trace_state);
1937 
1938 	return 0;
1939 }
1940 EXPORT_SYMBOL_GPL(synth_event_trace_end);
1941 
1942 static int create_synth_event(int argc, const char **argv)
1943 {
1944 	const char *name = argv[0];
1945 	int len;
1946 
1947 	if (name[0] != 's' || name[1] != ':')
1948 		return -ECANCELED;
1949 	name += 2;
1950 
1951 	/* This interface accepts group name prefix */
1952 	if (strchr(name, '/')) {
1953 		len = str_has_prefix(name, SYNTH_SYSTEM "/");
1954 		if (len == 0)
1955 			return -EINVAL;
1956 		name += len;
1957 	}
1958 	return __create_synth_event(argc - 1, name, argv + 1);
1959 }
1960 
1961 static int synth_event_release(struct dyn_event *ev)
1962 {
1963 	struct synth_event *event = to_synth_event(ev);
1964 	int ret;
1965 
1966 	if (event->ref)
1967 		return -EBUSY;
1968 
1969 	ret = unregister_synth_event(event);
1970 	if (ret)
1971 		return ret;
1972 
1973 	dyn_event_remove(ev);
1974 	free_synth_event(event);
1975 	return 0;
1976 }
1977 
1978 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
1979 {
1980 	struct synth_field *field;
1981 	unsigned int i;
1982 	char *type, *t;
1983 
1984 	seq_printf(m, "%s\t", event->name);
1985 
1986 	for (i = 0; i < event->n_fields; i++) {
1987 		field = event->fields[i];
1988 
1989 		type = field->type;
1990 		t = strstr(type, "__data_loc");
1991 		if (t) { /* __data_loc belongs in format but not event desc */
1992 			t += sizeof("__data_loc");
1993 			type = t;
1994 		}
1995 
1996 		/* parameter values */
1997 		seq_printf(m, "%s %s%s", type, field->name,
1998 			   i == event->n_fields - 1 ? "" : "; ");
1999 	}
2000 
2001 	seq_putc(m, '\n');
2002 
2003 	return 0;
2004 }
2005 
2006 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2007 {
2008 	struct synth_event *event = to_synth_event(ev);
2009 
2010 	seq_printf(m, "s:%s/", event->class.system);
2011 
2012 	return __synth_event_show(m, event);
2013 }
2014 
2015 static int synth_events_seq_show(struct seq_file *m, void *v)
2016 {
2017 	struct dyn_event *ev = v;
2018 
2019 	if (!is_synth_event(ev))
2020 		return 0;
2021 
2022 	return __synth_event_show(m, to_synth_event(ev));
2023 }
2024 
2025 static const struct seq_operations synth_events_seq_op = {
2026 	.start	= dyn_event_seq_start,
2027 	.next	= dyn_event_seq_next,
2028 	.stop	= dyn_event_seq_stop,
2029 	.show	= synth_events_seq_show,
2030 };
2031 
2032 static int synth_events_open(struct inode *inode, struct file *file)
2033 {
2034 	int ret;
2035 
2036 	ret = security_locked_down(LOCKDOWN_TRACEFS);
2037 	if (ret)
2038 		return ret;
2039 
2040 	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2041 		ret = dyn_events_release_all(&synth_event_ops);
2042 		if (ret < 0)
2043 			return ret;
2044 	}
2045 
2046 	return seq_open(file, &synth_events_seq_op);
2047 }
2048 
2049 static ssize_t synth_events_write(struct file *file,
2050 				  const char __user *buffer,
2051 				  size_t count, loff_t *ppos)
2052 {
2053 	return trace_parse_run_command(file, buffer, count, ppos,
2054 				       create_or_delete_synth_event);
2055 }
2056 
2057 static const struct file_operations synth_events_fops = {
2058 	.open           = synth_events_open,
2059 	.write		= synth_events_write,
2060 	.read           = seq_read,
2061 	.llseek         = seq_lseek,
2062 	.release        = seq_release,
2063 };
2064 
2065 /*
2066  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2067  * events in postcore_initcall without tracefs.
2068  */
2069 static __init int trace_events_synth_init_early(void)
2070 {
2071 	int err = 0;
2072 
2073 	err = dyn_event_register(&synth_event_ops);
2074 	if (err)
2075 		pr_warn("Could not register synth_event_ops\n");
2076 
2077 	return err;
2078 }
2079 core_initcall(trace_events_synth_init_early);
2080 
2081 static __init int trace_events_synth_init(void)
2082 {
2083 	struct dentry *entry = NULL;
2084 	int err = 0;
2085 	err = tracing_init_dentry();
2086 	if (err)
2087 		goto err;
2088 
2089 	entry = tracefs_create_file("synthetic_events", 0644, NULL,
2090 				    NULL, &synth_events_fops);
2091 	if (!entry) {
2092 		err = -ENODEV;
2093 		goto err;
2094 	}
2095 
2096 	return err;
2097  err:
2098 	pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2099 
2100 	return err;
2101 }
2102 
2103 fs_initcall(trace_events_synth_init);
2104