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rcu: Remove redundant check for rcu_head misalignment
[deliverable/linux.git] / kernel / trace / trace_events_filter.c
1 /*
2 * trace_events_filter - generic event filtering
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 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
19 */
20
21 #include <linux/module.h>
22 #include <linux/ctype.h>
23 #include <linux/mutex.h>
24 #include <linux/perf_event.h>
25 #include <linux/slab.h>
26
27 #include "trace.h"
28 #include "trace_output.h"
29
30 #define DEFAULT_SYS_FILTER_MESSAGE \
31 "### global filter ###\n" \
32 "# Use this to set filters for multiple events.\n" \
33 "# Only events with the given fields will be affected.\n" \
34 "# If no events are modified, an error message will be displayed here"
35
36 enum filter_op_ids
37 {
38 OP_OR,
39 OP_AND,
40 OP_GLOB,
41 OP_NE,
42 OP_EQ,
43 OP_LT,
44 OP_LE,
45 OP_GT,
46 OP_GE,
47 OP_NONE,
48 OP_OPEN_PAREN,
49 };
50
51 struct filter_op {
52 int id;
53 char *string;
54 int precedence;
55 };
56
57 static struct filter_op filter_ops[] = {
58 { OP_OR, "||", 1 },
59 { OP_AND, "&&", 2 },
60 { OP_GLOB, "~", 4 },
61 { OP_NE, "!=", 4 },
62 { OP_EQ, "==", 4 },
63 { OP_LT, "<", 5 },
64 { OP_LE, "<=", 5 },
65 { OP_GT, ">", 5 },
66 { OP_GE, ">=", 5 },
67 { OP_NONE, "OP_NONE", 0 },
68 { OP_OPEN_PAREN, "(", 0 },
69 };
70
71 enum {
72 FILT_ERR_NONE,
73 FILT_ERR_INVALID_OP,
74 FILT_ERR_UNBALANCED_PAREN,
75 FILT_ERR_TOO_MANY_OPERANDS,
76 FILT_ERR_OPERAND_TOO_LONG,
77 FILT_ERR_FIELD_NOT_FOUND,
78 FILT_ERR_ILLEGAL_FIELD_OP,
79 FILT_ERR_ILLEGAL_INTVAL,
80 FILT_ERR_BAD_SUBSYS_FILTER,
81 FILT_ERR_TOO_MANY_PREDS,
82 FILT_ERR_MISSING_FIELD,
83 FILT_ERR_INVALID_FILTER,
84 };
85
86 static char *err_text[] = {
87 "No error",
88 "Invalid operator",
89 "Unbalanced parens",
90 "Too many operands",
91 "Operand too long",
92 "Field not found",
93 "Illegal operation for field type",
94 "Illegal integer value",
95 "Couldn't find or set field in one of a subsystem's events",
96 "Too many terms in predicate expression",
97 "Missing field name and/or value",
98 "Meaningless filter expression",
99 };
100
101 struct opstack_op {
102 int op;
103 struct list_head list;
104 };
105
106 struct postfix_elt {
107 int op;
108 char *operand;
109 struct list_head list;
110 };
111
112 struct filter_parse_state {
113 struct filter_op *ops;
114 struct list_head opstack;
115 struct list_head postfix;
116 int lasterr;
117 int lasterr_pos;
118
119 struct {
120 char *string;
121 unsigned int cnt;
122 unsigned int tail;
123 } infix;
124
125 struct {
126 char string[MAX_FILTER_STR_VAL];
127 int pos;
128 unsigned int tail;
129 } operand;
130 };
131
132 struct pred_stack {
133 struct filter_pred **preds;
134 int index;
135 };
136
137 #define DEFINE_COMPARISON_PRED(type) \
138 static int filter_pred_##type(struct filter_pred *pred, void *event) \
139 { \
140 type *addr = (type *)(event + pred->offset); \
141 type val = (type)pred->val; \
142 int match = 0; \
143 \
144 switch (pred->op) { \
145 case OP_LT: \
146 match = (*addr < val); \
147 break; \
148 case OP_LE: \
149 match = (*addr <= val); \
150 break; \
151 case OP_GT: \
152 match = (*addr > val); \
153 break; \
154 case OP_GE: \
155 match = (*addr >= val); \
156 break; \
157 default: \
158 break; \
159 } \
160 \
161 return match; \
162 }
163
164 #define DEFINE_EQUALITY_PRED(size) \
165 static int filter_pred_##size(struct filter_pred *pred, void *event) \
166 { \
167 u##size *addr = (u##size *)(event + pred->offset); \
168 u##size val = (u##size)pred->val; \
169 int match; \
170 \
171 match = (val == *addr) ^ pred->not; \
172 \
173 return match; \
174 }
175
176 DEFINE_COMPARISON_PRED(s64);
177 DEFINE_COMPARISON_PRED(u64);
178 DEFINE_COMPARISON_PRED(s32);
179 DEFINE_COMPARISON_PRED(u32);
180 DEFINE_COMPARISON_PRED(s16);
181 DEFINE_COMPARISON_PRED(u16);
182 DEFINE_COMPARISON_PRED(s8);
183 DEFINE_COMPARISON_PRED(u8);
184
185 DEFINE_EQUALITY_PRED(64);
186 DEFINE_EQUALITY_PRED(32);
187 DEFINE_EQUALITY_PRED(16);
188 DEFINE_EQUALITY_PRED(8);
189
190 /* Filter predicate for fixed sized arrays of characters */
191 static int filter_pred_string(struct filter_pred *pred, void *event)
192 {
193 char *addr = (char *)(event + pred->offset);
194 int cmp, match;
195
196 cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len);
197
198 match = cmp ^ pred->not;
199
200 return match;
201 }
202
203 /* Filter predicate for char * pointers */
204 static int filter_pred_pchar(struct filter_pred *pred, void *event)
205 {
206 char **addr = (char **)(event + pred->offset);
207 int cmp, match;
208 int len = strlen(*addr) + 1; /* including tailing '\0' */
209
210 cmp = pred->regex.match(*addr, &pred->regex, len);
211
212 match = cmp ^ pred->not;
213
214 return match;
215 }
216
217 /*
218 * Filter predicate for dynamic sized arrays of characters.
219 * These are implemented through a list of strings at the end
220 * of the entry.
221 * Also each of these strings have a field in the entry which
222 * contains its offset from the beginning of the entry.
223 * We have then first to get this field, dereference it
224 * and add it to the address of the entry, and at last we have
225 * the address of the string.
226 */
227 static int filter_pred_strloc(struct filter_pred *pred, void *event)
228 {
229 u32 str_item = *(u32 *)(event + pred->offset);
230 int str_loc = str_item & 0xffff;
231 int str_len = str_item >> 16;
232 char *addr = (char *)(event + str_loc);
233 int cmp, match;
234
235 cmp = pred->regex.match(addr, &pred->regex, str_len);
236
237 match = cmp ^ pred->not;
238
239 return match;
240 }
241
242 static int filter_pred_none(struct filter_pred *pred, void *event)
243 {
244 return 0;
245 }
246
247 /*
248 * regex_match_foo - Basic regex callbacks
249 *
250 * @str: the string to be searched
251 * @r: the regex structure containing the pattern string
252 * @len: the length of the string to be searched (including '\0')
253 *
254 * Note:
255 * - @str might not be NULL-terminated if it's of type DYN_STRING
256 * or STATIC_STRING
257 */
258
259 static int regex_match_full(char *str, struct regex *r, int len)
260 {
261 if (strncmp(str, r->pattern, len) == 0)
262 return 1;
263 return 0;
264 }
265
266 static int regex_match_front(char *str, struct regex *r, int len)
267 {
268 if (strncmp(str, r->pattern, r->len) == 0)
269 return 1;
270 return 0;
271 }
272
273 static int regex_match_middle(char *str, struct regex *r, int len)
274 {
275 if (strnstr(str, r->pattern, len))
276 return 1;
277 return 0;
278 }
279
280 static int regex_match_end(char *str, struct regex *r, int len)
281 {
282 int strlen = len - 1;
283
284 if (strlen >= r->len &&
285 memcmp(str + strlen - r->len, r->pattern, r->len) == 0)
286 return 1;
287 return 0;
288 }
289
290 /**
291 * filter_parse_regex - parse a basic regex
292 * @buff: the raw regex
293 * @len: length of the regex
294 * @search: will point to the beginning of the string to compare
295 * @not: tell whether the match will have to be inverted
296 *
297 * This passes in a buffer containing a regex and this function will
298 * set search to point to the search part of the buffer and
299 * return the type of search it is (see enum above).
300 * This does modify buff.
301 *
302 * Returns enum type.
303 * search returns the pointer to use for comparison.
304 * not returns 1 if buff started with a '!'
305 * 0 otherwise.
306 */
307 enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
308 {
309 int type = MATCH_FULL;
310 int i;
311
312 if (buff[0] == '!') {
313 *not = 1;
314 buff++;
315 len--;
316 } else
317 *not = 0;
318
319 *search = buff;
320
321 for (i = 0; i < len; i++) {
322 if (buff[i] == '*') {
323 if (!i) {
324 *search = buff + 1;
325 type = MATCH_END_ONLY;
326 } else {
327 if (type == MATCH_END_ONLY)
328 type = MATCH_MIDDLE_ONLY;
329 else
330 type = MATCH_FRONT_ONLY;
331 buff[i] = 0;
332 break;
333 }
334 }
335 }
336
337 return type;
338 }
339
340 static void filter_build_regex(struct filter_pred *pred)
341 {
342 struct regex *r = &pred->regex;
343 char *search;
344 enum regex_type type = MATCH_FULL;
345 int not = 0;
346
347 if (pred->op == OP_GLOB) {
348 type = filter_parse_regex(r->pattern, r->len, &search, &not);
349 r->len = strlen(search);
350 memmove(r->pattern, search, r->len+1);
351 }
352
353 switch (type) {
354 case MATCH_FULL:
355 r->match = regex_match_full;
356 break;
357 case MATCH_FRONT_ONLY:
358 r->match = regex_match_front;
359 break;
360 case MATCH_MIDDLE_ONLY:
361 r->match = regex_match_middle;
362 break;
363 case MATCH_END_ONLY:
364 r->match = regex_match_end;
365 break;
366 }
367
368 pred->not ^= not;
369 }
370
371 enum move_type {
372 MOVE_DOWN,
373 MOVE_UP_FROM_LEFT,
374 MOVE_UP_FROM_RIGHT
375 };
376
377 static struct filter_pred *
378 get_pred_parent(struct filter_pred *pred, struct filter_pred *preds,
379 int index, enum move_type *move)
380 {
381 if (pred->parent & FILTER_PRED_IS_RIGHT)
382 *move = MOVE_UP_FROM_RIGHT;
383 else
384 *move = MOVE_UP_FROM_LEFT;
385 pred = &preds[pred->parent & ~FILTER_PRED_IS_RIGHT];
386
387 return pred;
388 }
389
390 enum walk_return {
391 WALK_PRED_ABORT,
392 WALK_PRED_PARENT,
393 WALK_PRED_DEFAULT,
394 };
395
396 typedef int (*filter_pred_walkcb_t) (enum move_type move,
397 struct filter_pred *pred,
398 int *err, void *data);
399
400 static int walk_pred_tree(struct filter_pred *preds,
401 struct filter_pred *root,
402 filter_pred_walkcb_t cb, void *data)
403 {
404 struct filter_pred *pred = root;
405 enum move_type move = MOVE_DOWN;
406 int done = 0;
407
408 if (!preds)
409 return -EINVAL;
410
411 do {
412 int err = 0, ret;
413
414 ret = cb(move, pred, &err, data);
415 if (ret == WALK_PRED_ABORT)
416 return err;
417 if (ret == WALK_PRED_PARENT)
418 goto get_parent;
419
420 switch (move) {
421 case MOVE_DOWN:
422 if (pred->left != FILTER_PRED_INVALID) {
423 pred = &preds[pred->left];
424 continue;
425 }
426 goto get_parent;
427 case MOVE_UP_FROM_LEFT:
428 pred = &preds[pred->right];
429 move = MOVE_DOWN;
430 continue;
431 case MOVE_UP_FROM_RIGHT:
432 get_parent:
433 if (pred == root)
434 break;
435 pred = get_pred_parent(pred, preds,
436 pred->parent,
437 &move);
438 continue;
439 }
440 done = 1;
441 } while (!done);
442
443 /* We are fine. */
444 return 0;
445 }
446
447 /*
448 * A series of AND or ORs where found together. Instead of
449 * climbing up and down the tree branches, an array of the
450 * ops were made in order of checks. We can just move across
451 * the array and short circuit if needed.
452 */
453 static int process_ops(struct filter_pred *preds,
454 struct filter_pred *op, void *rec)
455 {
456 struct filter_pred *pred;
457 int match = 0;
458 int type;
459 int i;
460
461 /*
462 * Micro-optimization: We set type to true if op
463 * is an OR and false otherwise (AND). Then we
464 * just need to test if the match is equal to
465 * the type, and if it is, we can short circuit the
466 * rest of the checks:
467 *
468 * if ((match && op->op == OP_OR) ||
469 * (!match && op->op == OP_AND))
470 * return match;
471 */
472 type = op->op == OP_OR;
473
474 for (i = 0; i < op->val; i++) {
475 pred = &preds[op->ops[i]];
476 if (!WARN_ON_ONCE(!pred->fn))
477 match = pred->fn(pred, rec);
478 if (!!match == type)
479 return match;
480 }
481 return match;
482 }
483
484 struct filter_match_preds_data {
485 struct filter_pred *preds;
486 int match;
487 void *rec;
488 };
489
490 static int filter_match_preds_cb(enum move_type move, struct filter_pred *pred,
491 int *err, void *data)
492 {
493 struct filter_match_preds_data *d = data;
494
495 *err = 0;
496 switch (move) {
497 case MOVE_DOWN:
498 /* only AND and OR have children */
499 if (pred->left != FILTER_PRED_INVALID) {
500 /* If ops is set, then it was folded. */
501 if (!pred->ops)
502 return WALK_PRED_DEFAULT;
503 /* We can treat folded ops as a leaf node */
504 d->match = process_ops(d->preds, pred, d->rec);
505 } else {
506 if (!WARN_ON_ONCE(!pred->fn))
507 d->match = pred->fn(pred, d->rec);
508 }
509
510 return WALK_PRED_PARENT;
511 case MOVE_UP_FROM_LEFT:
512 /*
513 * Check for short circuits.
514 *
515 * Optimization: !!match == (pred->op == OP_OR)
516 * is the same as:
517 * if ((match && pred->op == OP_OR) ||
518 * (!match && pred->op == OP_AND))
519 */
520 if (!!d->match == (pred->op == OP_OR))
521 return WALK_PRED_PARENT;
522 break;
523 case MOVE_UP_FROM_RIGHT:
524 break;
525 }
526
527 return WALK_PRED_DEFAULT;
528 }
529
530 /* return 1 if event matches, 0 otherwise (discard) */
531 int filter_match_preds(struct event_filter *filter, void *rec)
532 {
533 struct filter_pred *preds;
534 struct filter_pred *root;
535 struct filter_match_preds_data data = {
536 /* match is currently meaningless */
537 .match = -1,
538 .rec = rec,
539 };
540 int n_preds, ret;
541
542 /* no filter is considered a match */
543 if (!filter)
544 return 1;
545
546 n_preds = filter->n_preds;
547 if (!n_preds)
548 return 1;
549
550 /*
551 * n_preds, root and filter->preds are protect with preemption disabled.
552 */
553 root = rcu_dereference_sched(filter->root);
554 if (!root)
555 return 1;
556
557 data.preds = preds = rcu_dereference_sched(filter->preds);
558 ret = walk_pred_tree(preds, root, filter_match_preds_cb, &data);
559 WARN_ON(ret);
560 return data.match;
561 }
562 EXPORT_SYMBOL_GPL(filter_match_preds);
563
564 static void parse_error(struct filter_parse_state *ps, int err, int pos)
565 {
566 ps->lasterr = err;
567 ps->lasterr_pos = pos;
568 }
569
570 static void remove_filter_string(struct event_filter *filter)
571 {
572 if (!filter)
573 return;
574
575 kfree(filter->filter_string);
576 filter->filter_string = NULL;
577 }
578
579 static int replace_filter_string(struct event_filter *filter,
580 char *filter_string)
581 {
582 kfree(filter->filter_string);
583 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
584 if (!filter->filter_string)
585 return -ENOMEM;
586
587 return 0;
588 }
589
590 static int append_filter_string(struct event_filter *filter,
591 char *string)
592 {
593 int newlen;
594 char *new_filter_string;
595
596 BUG_ON(!filter->filter_string);
597 newlen = strlen(filter->filter_string) + strlen(string) + 1;
598 new_filter_string = kmalloc(newlen, GFP_KERNEL);
599 if (!new_filter_string)
600 return -ENOMEM;
601
602 strcpy(new_filter_string, filter->filter_string);
603 strcat(new_filter_string, string);
604 kfree(filter->filter_string);
605 filter->filter_string = new_filter_string;
606
607 return 0;
608 }
609
610 static void append_filter_err(struct filter_parse_state *ps,
611 struct event_filter *filter)
612 {
613 int pos = ps->lasterr_pos;
614 char *buf, *pbuf;
615
616 buf = (char *)__get_free_page(GFP_TEMPORARY);
617 if (!buf)
618 return;
619
620 append_filter_string(filter, "\n");
621 memset(buf, ' ', PAGE_SIZE);
622 if (pos > PAGE_SIZE - 128)
623 pos = 0;
624 buf[pos] = '^';
625 pbuf = &buf[pos] + 1;
626
627 sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
628 append_filter_string(filter, buf);
629 free_page((unsigned long) buf);
630 }
631
632 void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
633 {
634 struct event_filter *filter;
635
636 mutex_lock(&event_mutex);
637 filter = call->filter;
638 if (filter && filter->filter_string)
639 trace_seq_printf(s, "%s\n", filter->filter_string);
640 else
641 trace_seq_printf(s, "none\n");
642 mutex_unlock(&event_mutex);
643 }
644
645 void print_subsystem_event_filter(struct event_subsystem *system,
646 struct trace_seq *s)
647 {
648 struct event_filter *filter;
649
650 mutex_lock(&event_mutex);
651 filter = system->filter;
652 if (filter && filter->filter_string)
653 trace_seq_printf(s, "%s\n", filter->filter_string);
654 else
655 trace_seq_printf(s, DEFAULT_SYS_FILTER_MESSAGE "\n");
656 mutex_unlock(&event_mutex);
657 }
658
659 static struct ftrace_event_field *
660 __find_event_field(struct list_head *head, char *name)
661 {
662 struct ftrace_event_field *field;
663
664 list_for_each_entry(field, head, link) {
665 if (!strcmp(field->name, name))
666 return field;
667 }
668
669 return NULL;
670 }
671
672 static struct ftrace_event_field *
673 find_event_field(struct ftrace_event_call *call, char *name)
674 {
675 struct ftrace_event_field *field;
676 struct list_head *head;
677
678 field = __find_event_field(&ftrace_common_fields, name);
679 if (field)
680 return field;
681
682 head = trace_get_fields(call);
683 return __find_event_field(head, name);
684 }
685
686 static int __alloc_pred_stack(struct pred_stack *stack, int n_preds)
687 {
688 stack->preds = kzalloc(sizeof(*stack->preds)*(n_preds + 1), GFP_KERNEL);
689 if (!stack->preds)
690 return -ENOMEM;
691 stack->index = n_preds;
692 return 0;
693 }
694
695 static void __free_pred_stack(struct pred_stack *stack)
696 {
697 kfree(stack->preds);
698 stack->index = 0;
699 }
700
701 static int __push_pred_stack(struct pred_stack *stack,
702 struct filter_pred *pred)
703 {
704 int index = stack->index;
705
706 if (WARN_ON(index == 0))
707 return -ENOSPC;
708
709 stack->preds[--index] = pred;
710 stack->index = index;
711 return 0;
712 }
713
714 static struct filter_pred *
715 __pop_pred_stack(struct pred_stack *stack)
716 {
717 struct filter_pred *pred;
718 int index = stack->index;
719
720 pred = stack->preds[index++];
721 if (!pred)
722 return NULL;
723
724 stack->index = index;
725 return pred;
726 }
727
728 static int filter_set_pred(struct event_filter *filter,
729 int idx,
730 struct pred_stack *stack,
731 struct filter_pred *src)
732 {
733 struct filter_pred *dest = &filter->preds[idx];
734 struct filter_pred *left;
735 struct filter_pred *right;
736
737 *dest = *src;
738 dest->index = idx;
739
740 if (dest->op == OP_OR || dest->op == OP_AND) {
741 right = __pop_pred_stack(stack);
742 left = __pop_pred_stack(stack);
743 if (!left || !right)
744 return -EINVAL;
745 /*
746 * If both children can be folded
747 * and they are the same op as this op or a leaf,
748 * then this op can be folded.
749 */
750 if (left->index & FILTER_PRED_FOLD &&
751 (left->op == dest->op ||
752 left->left == FILTER_PRED_INVALID) &&
753 right->index & FILTER_PRED_FOLD &&
754 (right->op == dest->op ||
755 right->left == FILTER_PRED_INVALID))
756 dest->index |= FILTER_PRED_FOLD;
757
758 dest->left = left->index & ~FILTER_PRED_FOLD;
759 dest->right = right->index & ~FILTER_PRED_FOLD;
760 left->parent = dest->index & ~FILTER_PRED_FOLD;
761 right->parent = dest->index | FILTER_PRED_IS_RIGHT;
762 } else {
763 /*
764 * Make dest->left invalid to be used as a quick
765 * way to know this is a leaf node.
766 */
767 dest->left = FILTER_PRED_INVALID;
768
769 /* All leafs allow folding the parent ops. */
770 dest->index |= FILTER_PRED_FOLD;
771 }
772
773 return __push_pred_stack(stack, dest);
774 }
775
776 static void __free_preds(struct event_filter *filter)
777 {
778 if (filter->preds) {
779 kfree(filter->preds);
780 filter->preds = NULL;
781 }
782 filter->a_preds = 0;
783 filter->n_preds = 0;
784 }
785
786 static void filter_disable(struct ftrace_event_call *call)
787 {
788 call->flags &= ~TRACE_EVENT_FL_FILTERED;
789 }
790
791 static void __free_filter(struct event_filter *filter)
792 {
793 if (!filter)
794 return;
795
796 __free_preds(filter);
797 kfree(filter->filter_string);
798 kfree(filter);
799 }
800
801 /*
802 * Called when destroying the ftrace_event_call.
803 * The call is being freed, so we do not need to worry about
804 * the call being currently used. This is for module code removing
805 * the tracepoints from within it.
806 */
807 void destroy_preds(struct ftrace_event_call *call)
808 {
809 __free_filter(call->filter);
810 call->filter = NULL;
811 }
812
813 static struct event_filter *__alloc_filter(void)
814 {
815 struct event_filter *filter;
816
817 filter = kzalloc(sizeof(*filter), GFP_KERNEL);
818 return filter;
819 }
820
821 static int __alloc_preds(struct event_filter *filter, int n_preds)
822 {
823 struct filter_pred *pred;
824 int i;
825
826 if (filter->preds)
827 __free_preds(filter);
828
829 filter->preds =
830 kzalloc(sizeof(*filter->preds) * n_preds, GFP_KERNEL);
831
832 if (!filter->preds)
833 return -ENOMEM;
834
835 filter->a_preds = n_preds;
836 filter->n_preds = 0;
837
838 for (i = 0; i < n_preds; i++) {
839 pred = &filter->preds[i];
840 pred->fn = filter_pred_none;
841 }
842
843 return 0;
844 }
845
846 static void filter_free_subsystem_preds(struct event_subsystem *system)
847 {
848 struct ftrace_event_call *call;
849
850 list_for_each_entry(call, &ftrace_events, list) {
851 if (strcmp(call->class->system, system->name) != 0)
852 continue;
853
854 filter_disable(call);
855 remove_filter_string(call->filter);
856 }
857 }
858
859 static void filter_free_subsystem_filters(struct event_subsystem *system)
860 {
861 struct ftrace_event_call *call;
862
863 list_for_each_entry(call, &ftrace_events, list) {
864 if (strcmp(call->class->system, system->name) != 0)
865 continue;
866 __free_filter(call->filter);
867 call->filter = NULL;
868 }
869 }
870
871 static int filter_add_pred(struct filter_parse_state *ps,
872 struct event_filter *filter,
873 struct filter_pred *pred,
874 struct pred_stack *stack)
875 {
876 int err;
877
878 if (WARN_ON(filter->n_preds == filter->a_preds)) {
879 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
880 return -ENOSPC;
881 }
882
883 err = filter_set_pred(filter, filter->n_preds, stack, pred);
884 if (err)
885 return err;
886
887 filter->n_preds++;
888
889 return 0;
890 }
891
892 int filter_assign_type(const char *type)
893 {
894 if (strstr(type, "__data_loc") && strstr(type, "char"))
895 return FILTER_DYN_STRING;
896
897 if (strchr(type, '[') && strstr(type, "char"))
898 return FILTER_STATIC_STRING;
899
900 return FILTER_OTHER;
901 }
902
903 static bool is_string_field(struct ftrace_event_field *field)
904 {
905 return field->filter_type == FILTER_DYN_STRING ||
906 field->filter_type == FILTER_STATIC_STRING ||
907 field->filter_type == FILTER_PTR_STRING;
908 }
909
910 static int is_legal_op(struct ftrace_event_field *field, int op)
911 {
912 if (is_string_field(field) &&
913 (op != OP_EQ && op != OP_NE && op != OP_GLOB))
914 return 0;
915 if (!is_string_field(field) && op == OP_GLOB)
916 return 0;
917
918 return 1;
919 }
920
921 static filter_pred_fn_t select_comparison_fn(int op, int field_size,
922 int field_is_signed)
923 {
924 filter_pred_fn_t fn = NULL;
925
926 switch (field_size) {
927 case 8:
928 if (op == OP_EQ || op == OP_NE)
929 fn = filter_pred_64;
930 else if (field_is_signed)
931 fn = filter_pred_s64;
932 else
933 fn = filter_pred_u64;
934 break;
935 case 4:
936 if (op == OP_EQ || op == OP_NE)
937 fn = filter_pred_32;
938 else if (field_is_signed)
939 fn = filter_pred_s32;
940 else
941 fn = filter_pred_u32;
942 break;
943 case 2:
944 if (op == OP_EQ || op == OP_NE)
945 fn = filter_pred_16;
946 else if (field_is_signed)
947 fn = filter_pred_s16;
948 else
949 fn = filter_pred_u16;
950 break;
951 case 1:
952 if (op == OP_EQ || op == OP_NE)
953 fn = filter_pred_8;
954 else if (field_is_signed)
955 fn = filter_pred_s8;
956 else
957 fn = filter_pred_u8;
958 break;
959 }
960
961 return fn;
962 }
963
964 static int init_pred(struct filter_parse_state *ps,
965 struct ftrace_event_field *field,
966 struct filter_pred *pred)
967
968 {
969 filter_pred_fn_t fn = filter_pred_none;
970 unsigned long long val;
971 int ret;
972
973 pred->offset = field->offset;
974
975 if (!is_legal_op(field, pred->op)) {
976 parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
977 return -EINVAL;
978 }
979
980 if (is_string_field(field)) {
981 filter_build_regex(pred);
982
983 if (field->filter_type == FILTER_STATIC_STRING) {
984 fn = filter_pred_string;
985 pred->regex.field_len = field->size;
986 } else if (field->filter_type == FILTER_DYN_STRING)
987 fn = filter_pred_strloc;
988 else
989 fn = filter_pred_pchar;
990 } else {
991 if (field->is_signed)
992 ret = strict_strtoll(pred->regex.pattern, 0, &val);
993 else
994 ret = strict_strtoull(pred->regex.pattern, 0, &val);
995 if (ret) {
996 parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
997 return -EINVAL;
998 }
999 pred->val = val;
1000
1001 fn = select_comparison_fn(pred->op, field->size,
1002 field->is_signed);
1003 if (!fn) {
1004 parse_error(ps, FILT_ERR_INVALID_OP, 0);
1005 return -EINVAL;
1006 }
1007 }
1008
1009 if (pred->op == OP_NE)
1010 pred->not = 1;
1011
1012 pred->fn = fn;
1013 return 0;
1014 }
1015
1016 static void parse_init(struct filter_parse_state *ps,
1017 struct filter_op *ops,
1018 char *infix_string)
1019 {
1020 memset(ps, '\0', sizeof(*ps));
1021
1022 ps->infix.string = infix_string;
1023 ps->infix.cnt = strlen(infix_string);
1024 ps->ops = ops;
1025
1026 INIT_LIST_HEAD(&ps->opstack);
1027 INIT_LIST_HEAD(&ps->postfix);
1028 }
1029
1030 static char infix_next(struct filter_parse_state *ps)
1031 {
1032 ps->infix.cnt--;
1033
1034 return ps->infix.string[ps->infix.tail++];
1035 }
1036
1037 static char infix_peek(struct filter_parse_state *ps)
1038 {
1039 if (ps->infix.tail == strlen(ps->infix.string))
1040 return 0;
1041
1042 return ps->infix.string[ps->infix.tail];
1043 }
1044
1045 static void infix_advance(struct filter_parse_state *ps)
1046 {
1047 ps->infix.cnt--;
1048 ps->infix.tail++;
1049 }
1050
1051 static inline int is_precedence_lower(struct filter_parse_state *ps,
1052 int a, int b)
1053 {
1054 return ps->ops[a].precedence < ps->ops[b].precedence;
1055 }
1056
1057 static inline int is_op_char(struct filter_parse_state *ps, char c)
1058 {
1059 int i;
1060
1061 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
1062 if (ps->ops[i].string[0] == c)
1063 return 1;
1064 }
1065
1066 return 0;
1067 }
1068
1069 static int infix_get_op(struct filter_parse_state *ps, char firstc)
1070 {
1071 char nextc = infix_peek(ps);
1072 char opstr[3];
1073 int i;
1074
1075 opstr[0] = firstc;
1076 opstr[1] = nextc;
1077 opstr[2] = '\0';
1078
1079 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
1080 if (!strcmp(opstr, ps->ops[i].string)) {
1081 infix_advance(ps);
1082 return ps->ops[i].id;
1083 }
1084 }
1085
1086 opstr[1] = '\0';
1087
1088 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
1089 if (!strcmp(opstr, ps->ops[i].string))
1090 return ps->ops[i].id;
1091 }
1092
1093 return OP_NONE;
1094 }
1095
1096 static inline void clear_operand_string(struct filter_parse_state *ps)
1097 {
1098 memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
1099 ps->operand.tail = 0;
1100 }
1101
1102 static inline int append_operand_char(struct filter_parse_state *ps, char c)
1103 {
1104 if (ps->operand.tail == MAX_FILTER_STR_VAL - 1)
1105 return -EINVAL;
1106
1107 ps->operand.string[ps->operand.tail++] = c;
1108
1109 return 0;
1110 }
1111
1112 static int filter_opstack_push(struct filter_parse_state *ps, int op)
1113 {
1114 struct opstack_op *opstack_op;
1115
1116 opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
1117 if (!opstack_op)
1118 return -ENOMEM;
1119
1120 opstack_op->op = op;
1121 list_add(&opstack_op->list, &ps->opstack);
1122
1123 return 0;
1124 }
1125
1126 static int filter_opstack_empty(struct filter_parse_state *ps)
1127 {
1128 return list_empty(&ps->opstack);
1129 }
1130
1131 static int filter_opstack_top(struct filter_parse_state *ps)
1132 {
1133 struct opstack_op *opstack_op;
1134
1135 if (filter_opstack_empty(ps))
1136 return OP_NONE;
1137
1138 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
1139
1140 return opstack_op->op;
1141 }
1142
1143 static int filter_opstack_pop(struct filter_parse_state *ps)
1144 {
1145 struct opstack_op *opstack_op;
1146 int op;
1147
1148 if (filter_opstack_empty(ps))
1149 return OP_NONE;
1150
1151 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
1152 op = opstack_op->op;
1153 list_del(&opstack_op->list);
1154
1155 kfree(opstack_op);
1156
1157 return op;
1158 }
1159
1160 static void filter_opstack_clear(struct filter_parse_state *ps)
1161 {
1162 while (!filter_opstack_empty(ps))
1163 filter_opstack_pop(ps);
1164 }
1165
1166 static char *curr_operand(struct filter_parse_state *ps)
1167 {
1168 return ps->operand.string;
1169 }
1170
1171 static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
1172 {
1173 struct postfix_elt *elt;
1174
1175 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
1176 if (!elt)
1177 return -ENOMEM;
1178
1179 elt->op = OP_NONE;
1180 elt->operand = kstrdup(operand, GFP_KERNEL);
1181 if (!elt->operand) {
1182 kfree(elt);
1183 return -ENOMEM;
1184 }
1185
1186 list_add_tail(&elt->list, &ps->postfix);
1187
1188 return 0;
1189 }
1190
1191 static int postfix_append_op(struct filter_parse_state *ps, int op)
1192 {
1193 struct postfix_elt *elt;
1194
1195 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
1196 if (!elt)
1197 return -ENOMEM;
1198
1199 elt->op = op;
1200 elt->operand = NULL;
1201
1202 list_add_tail(&elt->list, &ps->postfix);
1203
1204 return 0;
1205 }
1206
1207 static void postfix_clear(struct filter_parse_state *ps)
1208 {
1209 struct postfix_elt *elt;
1210
1211 while (!list_empty(&ps->postfix)) {
1212 elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
1213 list_del(&elt->list);
1214 kfree(elt->operand);
1215 kfree(elt);
1216 }
1217 }
1218
1219 static int filter_parse(struct filter_parse_state *ps)
1220 {
1221 int in_string = 0;
1222 int op, top_op;
1223 char ch;
1224
1225 while ((ch = infix_next(ps))) {
1226 if (ch == '"') {
1227 in_string ^= 1;
1228 continue;
1229 }
1230
1231 if (in_string)
1232 goto parse_operand;
1233
1234 if (isspace(ch))
1235 continue;
1236
1237 if (is_op_char(ps, ch)) {
1238 op = infix_get_op(ps, ch);
1239 if (op == OP_NONE) {
1240 parse_error(ps, FILT_ERR_INVALID_OP, 0);
1241 return -EINVAL;
1242 }
1243
1244 if (strlen(curr_operand(ps))) {
1245 postfix_append_operand(ps, curr_operand(ps));
1246 clear_operand_string(ps);
1247 }
1248
1249 while (!filter_opstack_empty(ps)) {
1250 top_op = filter_opstack_top(ps);
1251 if (!is_precedence_lower(ps, top_op, op)) {
1252 top_op = filter_opstack_pop(ps);
1253 postfix_append_op(ps, top_op);
1254 continue;
1255 }
1256 break;
1257 }
1258
1259 filter_opstack_push(ps, op);
1260 continue;
1261 }
1262
1263 if (ch == '(') {
1264 filter_opstack_push(ps, OP_OPEN_PAREN);
1265 continue;
1266 }
1267
1268 if (ch == ')') {
1269 if (strlen(curr_operand(ps))) {
1270 postfix_append_operand(ps, curr_operand(ps));
1271 clear_operand_string(ps);
1272 }
1273
1274 top_op = filter_opstack_pop(ps);
1275 while (top_op != OP_NONE) {
1276 if (top_op == OP_OPEN_PAREN)
1277 break;
1278 postfix_append_op(ps, top_op);
1279 top_op = filter_opstack_pop(ps);
1280 }
1281 if (top_op == OP_NONE) {
1282 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
1283 return -EINVAL;
1284 }
1285 continue;
1286 }
1287 parse_operand:
1288 if (append_operand_char(ps, ch)) {
1289 parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
1290 return -EINVAL;
1291 }
1292 }
1293
1294 if (strlen(curr_operand(ps)))
1295 postfix_append_operand(ps, curr_operand(ps));
1296
1297 while (!filter_opstack_empty(ps)) {
1298 top_op = filter_opstack_pop(ps);
1299 if (top_op == OP_NONE)
1300 break;
1301 if (top_op == OP_OPEN_PAREN) {
1302 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
1303 return -EINVAL;
1304 }
1305 postfix_append_op(ps, top_op);
1306 }
1307
1308 return 0;
1309 }
1310
1311 static struct filter_pred *create_pred(struct filter_parse_state *ps,
1312 struct ftrace_event_call *call,
1313 int op, char *operand1, char *operand2)
1314 {
1315 struct ftrace_event_field *field;
1316 static struct filter_pred pred;
1317
1318 memset(&pred, 0, sizeof(pred));
1319 pred.op = op;
1320
1321 if (op == OP_AND || op == OP_OR)
1322 return &pred;
1323
1324 if (!operand1 || !operand2) {
1325 parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
1326 return NULL;
1327 }
1328
1329 field = find_event_field(call, operand1);
1330 if (!field) {
1331 parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
1332 return NULL;
1333 }
1334
1335 strcpy(pred.regex.pattern, operand2);
1336 pred.regex.len = strlen(pred.regex.pattern);
1337
1338 #ifdef CONFIG_FTRACE_STARTUP_TEST
1339 pred.field = field;
1340 #endif
1341 return init_pred(ps, field, &pred) ? NULL : &pred;
1342 }
1343
1344 static int check_preds(struct filter_parse_state *ps)
1345 {
1346 int n_normal_preds = 0, n_logical_preds = 0;
1347 struct postfix_elt *elt;
1348
1349 list_for_each_entry(elt, &ps->postfix, list) {
1350 if (elt->op == OP_NONE)
1351 continue;
1352
1353 if (elt->op == OP_AND || elt->op == OP_OR) {
1354 n_logical_preds++;
1355 continue;
1356 }
1357 n_normal_preds++;
1358 }
1359
1360 if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
1361 parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
1362 return -EINVAL;
1363 }
1364
1365 return 0;
1366 }
1367
1368 static int count_preds(struct filter_parse_state *ps)
1369 {
1370 struct postfix_elt *elt;
1371 int n_preds = 0;
1372
1373 list_for_each_entry(elt, &ps->postfix, list) {
1374 if (elt->op == OP_NONE)
1375 continue;
1376 n_preds++;
1377 }
1378
1379 return n_preds;
1380 }
1381
1382 struct check_pred_data {
1383 int count;
1384 int max;
1385 };
1386
1387 static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred,
1388 int *err, void *data)
1389 {
1390 struct check_pred_data *d = data;
1391
1392 if (WARN_ON(d->count++ > d->max)) {
1393 *err = -EINVAL;
1394 return WALK_PRED_ABORT;
1395 }
1396 return WALK_PRED_DEFAULT;
1397 }
1398
1399 /*
1400 * The tree is walked at filtering of an event. If the tree is not correctly
1401 * built, it may cause an infinite loop. Check here that the tree does
1402 * indeed terminate.
1403 */
1404 static int check_pred_tree(struct event_filter *filter,
1405 struct filter_pred *root)
1406 {
1407 struct check_pred_data data = {
1408 /*
1409 * The max that we can hit a node is three times.
1410 * Once going down, once coming up from left, and
1411 * once coming up from right. This is more than enough
1412 * since leafs are only hit a single time.
1413 */
1414 .max = 3 * filter->n_preds,
1415 .count = 0,
1416 };
1417
1418 return walk_pred_tree(filter->preds, root,
1419 check_pred_tree_cb, &data);
1420 }
1421
1422 static int count_leafs_cb(enum move_type move, struct filter_pred *pred,
1423 int *err, void *data)
1424 {
1425 int *count = data;
1426
1427 if ((move == MOVE_DOWN) &&
1428 (pred->left == FILTER_PRED_INVALID))
1429 (*count)++;
1430
1431 return WALK_PRED_DEFAULT;
1432 }
1433
1434 static int count_leafs(struct filter_pred *preds, struct filter_pred *root)
1435 {
1436 int count = 0, ret;
1437
1438 ret = walk_pred_tree(preds, root, count_leafs_cb, &count);
1439 WARN_ON(ret);
1440 return count;
1441 }
1442
1443 struct fold_pred_data {
1444 struct filter_pred *root;
1445 int count;
1446 int children;
1447 };
1448
1449 static int fold_pred_cb(enum move_type move, struct filter_pred *pred,
1450 int *err, void *data)
1451 {
1452 struct fold_pred_data *d = data;
1453 struct filter_pred *root = d->root;
1454
1455 if (move != MOVE_DOWN)
1456 return WALK_PRED_DEFAULT;
1457 if (pred->left != FILTER_PRED_INVALID)
1458 return WALK_PRED_DEFAULT;
1459
1460 if (WARN_ON(d->count == d->children)) {
1461 *err = -EINVAL;
1462 return WALK_PRED_ABORT;
1463 }
1464
1465 pred->index &= ~FILTER_PRED_FOLD;
1466 root->ops[d->count++] = pred->index;
1467 return WALK_PRED_DEFAULT;
1468 }
1469
1470 static int fold_pred(struct filter_pred *preds, struct filter_pred *root)
1471 {
1472 struct fold_pred_data data = {
1473 .root = root,
1474 .count = 0,
1475 };
1476 int children;
1477
1478 /* No need to keep the fold flag */
1479 root->index &= ~FILTER_PRED_FOLD;
1480
1481 /* If the root is a leaf then do nothing */
1482 if (root->left == FILTER_PRED_INVALID)
1483 return 0;
1484
1485 /* count the children */
1486 children = count_leafs(preds, &preds[root->left]);
1487 children += count_leafs(preds, &preds[root->right]);
1488
1489 root->ops = kzalloc(sizeof(*root->ops) * children, GFP_KERNEL);
1490 if (!root->ops)
1491 return -ENOMEM;
1492
1493 root->val = children;
1494 data.children = children;
1495 return walk_pred_tree(preds, root, fold_pred_cb, &data);
1496 }
1497
1498 static int fold_pred_tree_cb(enum move_type move, struct filter_pred *pred,
1499 int *err, void *data)
1500 {
1501 struct filter_pred *preds = data;
1502
1503 if (move != MOVE_DOWN)
1504 return WALK_PRED_DEFAULT;
1505 if (!(pred->index & FILTER_PRED_FOLD))
1506 return WALK_PRED_DEFAULT;
1507
1508 *err = fold_pred(preds, pred);
1509 if (*err)
1510 return WALK_PRED_ABORT;
1511
1512 /* eveyrhing below is folded, continue with parent */
1513 return WALK_PRED_PARENT;
1514 }
1515
1516 /*
1517 * To optimize the processing of the ops, if we have several "ors" or
1518 * "ands" together, we can put them in an array and process them all
1519 * together speeding up the filter logic.
1520 */
1521 static int fold_pred_tree(struct event_filter *filter,
1522 struct filter_pred *root)
1523 {
1524 return walk_pred_tree(filter->preds, root, fold_pred_tree_cb,
1525 filter->preds);
1526 }
1527
1528 static int replace_preds(struct ftrace_event_call *call,
1529 struct event_filter *filter,
1530 struct filter_parse_state *ps,
1531 char *filter_string,
1532 bool dry_run)
1533 {
1534 char *operand1 = NULL, *operand2 = NULL;
1535 struct filter_pred *pred;
1536 struct filter_pred *root;
1537 struct postfix_elt *elt;
1538 struct pred_stack stack = { }; /* init to NULL */
1539 int err;
1540 int n_preds = 0;
1541
1542 n_preds = count_preds(ps);
1543 if (n_preds >= MAX_FILTER_PRED) {
1544 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1545 return -ENOSPC;
1546 }
1547
1548 err = check_preds(ps);
1549 if (err)
1550 return err;
1551
1552 if (!dry_run) {
1553 err = __alloc_pred_stack(&stack, n_preds);
1554 if (err)
1555 return err;
1556 err = __alloc_preds(filter, n_preds);
1557 if (err)
1558 goto fail;
1559 }
1560
1561 n_preds = 0;
1562 list_for_each_entry(elt, &ps->postfix, list) {
1563 if (elt->op == OP_NONE) {
1564 if (!operand1)
1565 operand1 = elt->operand;
1566 else if (!operand2)
1567 operand2 = elt->operand;
1568 else {
1569 parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
1570 err = -EINVAL;
1571 goto fail;
1572 }
1573 continue;
1574 }
1575
1576 if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
1577 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1578 err = -ENOSPC;
1579 goto fail;
1580 }
1581
1582 pred = create_pred(ps, call, elt->op, operand1, operand2);
1583 if (!pred) {
1584 err = -EINVAL;
1585 goto fail;
1586 }
1587
1588 if (!dry_run) {
1589 err = filter_add_pred(ps, filter, pred, &stack);
1590 if (err)
1591 goto fail;
1592 }
1593
1594 operand1 = operand2 = NULL;
1595 }
1596
1597 if (!dry_run) {
1598 /* We should have one item left on the stack */
1599 pred = __pop_pred_stack(&stack);
1600 if (!pred)
1601 return -EINVAL;
1602 /* This item is where we start from in matching */
1603 root = pred;
1604 /* Make sure the stack is empty */
1605 pred = __pop_pred_stack(&stack);
1606 if (WARN_ON(pred)) {
1607 err = -EINVAL;
1608 filter->root = NULL;
1609 goto fail;
1610 }
1611 err = check_pred_tree(filter, root);
1612 if (err)
1613 goto fail;
1614
1615 /* Optimize the tree */
1616 err = fold_pred_tree(filter, root);
1617 if (err)
1618 goto fail;
1619
1620 /* We don't set root until we know it works */
1621 barrier();
1622 filter->root = root;
1623 }
1624
1625 err = 0;
1626 fail:
1627 __free_pred_stack(&stack);
1628 return err;
1629 }
1630
1631 struct filter_list {
1632 struct list_head list;
1633 struct event_filter *filter;
1634 };
1635
1636 static int replace_system_preds(struct event_subsystem *system,
1637 struct filter_parse_state *ps,
1638 char *filter_string)
1639 {
1640 struct ftrace_event_call *call;
1641 struct filter_list *filter_item;
1642 struct filter_list *tmp;
1643 LIST_HEAD(filter_list);
1644 bool fail = true;
1645 int err;
1646
1647 list_for_each_entry(call, &ftrace_events, list) {
1648
1649 if (strcmp(call->class->system, system->name) != 0)
1650 continue;
1651
1652 /*
1653 * Try to see if the filter can be applied
1654 * (filter arg is ignored on dry_run)
1655 */
1656 err = replace_preds(call, NULL, ps, filter_string, true);
1657 if (err)
1658 call->flags |= TRACE_EVENT_FL_NO_SET_FILTER;
1659 else
1660 call->flags &= ~TRACE_EVENT_FL_NO_SET_FILTER;
1661 }
1662
1663 list_for_each_entry(call, &ftrace_events, list) {
1664 struct event_filter *filter;
1665
1666 if (strcmp(call->class->system, system->name) != 0)
1667 continue;
1668
1669 if (call->flags & TRACE_EVENT_FL_NO_SET_FILTER)
1670 continue;
1671
1672 filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
1673 if (!filter_item)
1674 goto fail_mem;
1675
1676 list_add_tail(&filter_item->list, &filter_list);
1677
1678 filter_item->filter = __alloc_filter();
1679 if (!filter_item->filter)
1680 goto fail_mem;
1681 filter = filter_item->filter;
1682
1683 /* Can only fail on no memory */
1684 err = replace_filter_string(filter, filter_string);
1685 if (err)
1686 goto fail_mem;
1687
1688 err = replace_preds(call, filter, ps, filter_string, false);
1689 if (err) {
1690 filter_disable(call);
1691 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1692 append_filter_err(ps, filter);
1693 } else
1694 call->flags |= TRACE_EVENT_FL_FILTERED;
1695 /*
1696 * Regardless of if this returned an error, we still
1697 * replace the filter for the call.
1698 */
1699 filter = call->filter;
1700 rcu_assign_pointer(call->filter, filter_item->filter);
1701 filter_item->filter = filter;
1702
1703 fail = false;
1704 }
1705
1706 if (fail)
1707 goto fail;
1708
1709 /*
1710 * The calls can still be using the old filters.
1711 * Do a synchronize_sched() to ensure all calls are
1712 * done with them before we free them.
1713 */
1714 synchronize_sched();
1715 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1716 __free_filter(filter_item->filter);
1717 list_del(&filter_item->list);
1718 kfree(filter_item);
1719 }
1720 return 0;
1721 fail:
1722 /* No call succeeded */
1723 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1724 list_del(&filter_item->list);
1725 kfree(filter_item);
1726 }
1727 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1728 return -EINVAL;
1729 fail_mem:
1730 /* If any call succeeded, we still need to sync */
1731 if (!fail)
1732 synchronize_sched();
1733 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1734 __free_filter(filter_item->filter);
1735 list_del(&filter_item->list);
1736 kfree(filter_item);
1737 }
1738 return -ENOMEM;
1739 }
1740
1741 static int create_filter_start(char *filter_str, bool set_str,
1742 struct filter_parse_state **psp,
1743 struct event_filter **filterp)
1744 {
1745 struct event_filter *filter;
1746 struct filter_parse_state *ps = NULL;
1747 int err = 0;
1748
1749 WARN_ON_ONCE(*psp || *filterp);
1750
1751 /* allocate everything, and if any fails, free all and fail */
1752 filter = __alloc_filter();
1753 if (filter && set_str)
1754 err = replace_filter_string(filter, filter_str);
1755
1756 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1757
1758 if (!filter || !ps || err) {
1759 kfree(ps);
1760 __free_filter(filter);
1761 return -ENOMEM;
1762 }
1763
1764 /* we're committed to creating a new filter */
1765 *filterp = filter;
1766 *psp = ps;
1767
1768 parse_init(ps, filter_ops, filter_str);
1769 err = filter_parse(ps);
1770 if (err && set_str)
1771 append_filter_err(ps, filter);
1772 return err;
1773 }
1774
1775 static void create_filter_finish(struct filter_parse_state *ps)
1776 {
1777 if (ps) {
1778 filter_opstack_clear(ps);
1779 postfix_clear(ps);
1780 kfree(ps);
1781 }
1782 }
1783
1784 /**
1785 * create_filter - create a filter for a ftrace_event_call
1786 * @call: ftrace_event_call to create a filter for
1787 * @filter_str: filter string
1788 * @set_str: remember @filter_str and enable detailed error in filter
1789 * @filterp: out param for created filter (always updated on return)
1790 *
1791 * Creates a filter for @call with @filter_str. If @set_str is %true,
1792 * @filter_str is copied and recorded in the new filter.
1793 *
1794 * On success, returns 0 and *@filterp points to the new filter. On
1795 * failure, returns -errno and *@filterp may point to %NULL or to a new
1796 * filter. In the latter case, the returned filter contains error
1797 * information if @set_str is %true and the caller is responsible for
1798 * freeing it.
1799 */
1800 static int create_filter(struct ftrace_event_call *call,
1801 char *filter_str, bool set_str,
1802 struct event_filter **filterp)
1803 {
1804 struct event_filter *filter = NULL;
1805 struct filter_parse_state *ps = NULL;
1806 int err;
1807
1808 err = create_filter_start(filter_str, set_str, &ps, &filter);
1809 if (!err) {
1810 err = replace_preds(call, filter, ps, filter_str, false);
1811 if (err && set_str)
1812 append_filter_err(ps, filter);
1813 }
1814 create_filter_finish(ps);
1815
1816 *filterp = filter;
1817 return err;
1818 }
1819
1820 /**
1821 * create_system_filter - create a filter for an event_subsystem
1822 * @system: event_subsystem to create a filter for
1823 * @filter_str: filter string
1824 * @filterp: out param for created filter (always updated on return)
1825 *
1826 * Identical to create_filter() except that it creates a subsystem filter
1827 * and always remembers @filter_str.
1828 */
1829 static int create_system_filter(struct event_subsystem *system,
1830 char *filter_str, struct event_filter **filterp)
1831 {
1832 struct event_filter *filter = NULL;
1833 struct filter_parse_state *ps = NULL;
1834 int err;
1835
1836 err = create_filter_start(filter_str, true, &ps, &filter);
1837 if (!err) {
1838 err = replace_system_preds(system, ps, filter_str);
1839 if (!err) {
1840 /* System filters just show a default message */
1841 kfree(filter->filter_string);
1842 filter->filter_string = NULL;
1843 } else {
1844 append_filter_err(ps, filter);
1845 }
1846 }
1847 create_filter_finish(ps);
1848
1849 *filterp = filter;
1850 return err;
1851 }
1852
1853 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
1854 {
1855 struct event_filter *filter;
1856 int err = 0;
1857
1858 mutex_lock(&event_mutex);
1859
1860 if (!strcmp(strstrip(filter_string), "0")) {
1861 filter_disable(call);
1862 filter = call->filter;
1863 if (!filter)
1864 goto out_unlock;
1865 RCU_INIT_POINTER(call->filter, NULL);
1866 /* Make sure the filter is not being used */
1867 synchronize_sched();
1868 __free_filter(filter);
1869 goto out_unlock;
1870 }
1871
1872 err = create_filter(call, filter_string, true, &filter);
1873
1874 /*
1875 * Always swap the call filter with the new filter
1876 * even if there was an error. If there was an error
1877 * in the filter, we disable the filter and show the error
1878 * string
1879 */
1880 if (filter) {
1881 struct event_filter *tmp = call->filter;
1882
1883 if (!err)
1884 call->flags |= TRACE_EVENT_FL_FILTERED;
1885 else
1886 filter_disable(call);
1887
1888 rcu_assign_pointer(call->filter, filter);
1889
1890 if (tmp) {
1891 /* Make sure the call is done with the filter */
1892 synchronize_sched();
1893 __free_filter(tmp);
1894 }
1895 }
1896 out_unlock:
1897 mutex_unlock(&event_mutex);
1898
1899 return err;
1900 }
1901
1902 int apply_subsystem_event_filter(struct event_subsystem *system,
1903 char *filter_string)
1904 {
1905 struct event_filter *filter;
1906 int err = 0;
1907
1908 mutex_lock(&event_mutex);
1909
1910 /* Make sure the system still has events */
1911 if (!system->nr_events) {
1912 err = -ENODEV;
1913 goto out_unlock;
1914 }
1915
1916 if (!strcmp(strstrip(filter_string), "0")) {
1917 filter_free_subsystem_preds(system);
1918 remove_filter_string(system->filter);
1919 filter = system->filter;
1920 system->filter = NULL;
1921 /* Ensure all filters are no longer used */
1922 synchronize_sched();
1923 filter_free_subsystem_filters(system);
1924 __free_filter(filter);
1925 goto out_unlock;
1926 }
1927
1928 err = create_system_filter(system, filter_string, &filter);
1929 if (filter) {
1930 /*
1931 * No event actually uses the system filter
1932 * we can free it without synchronize_sched().
1933 */
1934 __free_filter(system->filter);
1935 system->filter = filter;
1936 }
1937 out_unlock:
1938 mutex_unlock(&event_mutex);
1939
1940 return err;
1941 }
1942
1943 #ifdef CONFIG_PERF_EVENTS
1944
1945 void ftrace_profile_free_filter(struct perf_event *event)
1946 {
1947 struct event_filter *filter = event->filter;
1948
1949 event->filter = NULL;
1950 __free_filter(filter);
1951 }
1952
1953 int ftrace_profile_set_filter(struct perf_event *event, int event_id,
1954 char *filter_str)
1955 {
1956 int err;
1957 struct event_filter *filter;
1958 struct ftrace_event_call *call;
1959
1960 mutex_lock(&event_mutex);
1961
1962 call = event->tp_event;
1963
1964 err = -EINVAL;
1965 if (!call)
1966 goto out_unlock;
1967
1968 err = -EEXIST;
1969 if (event->filter)
1970 goto out_unlock;
1971
1972 err = create_filter(call, filter_str, false, &filter);
1973 if (!err)
1974 event->filter = filter;
1975 else
1976 __free_filter(filter);
1977
1978 out_unlock:
1979 mutex_unlock(&event_mutex);
1980
1981 return err;
1982 }
1983
1984 #endif /* CONFIG_PERF_EVENTS */
1985
1986 #ifdef CONFIG_FTRACE_STARTUP_TEST
1987
1988 #include <linux/types.h>
1989 #include <linux/tracepoint.h>
1990
1991 #define CREATE_TRACE_POINTS
1992 #include "trace_events_filter_test.h"
1993
1994 #define DATA_REC(m, va, vb, vc, vd, ve, vf, vg, vh, nvisit) \
1995 { \
1996 .filter = FILTER, \
1997 .rec = { .a = va, .b = vb, .c = vc, .d = vd, \
1998 .e = ve, .f = vf, .g = vg, .h = vh }, \
1999 .match = m, \
2000 .not_visited = nvisit, \
2001 }
2002 #define YES 1
2003 #define NO 0
2004
2005 static struct test_filter_data_t {
2006 char *filter;
2007 struct ftrace_raw_ftrace_test_filter rec;
2008 int match;
2009 char *not_visited;
2010 } test_filter_data[] = {
2011 #define FILTER "a == 1 && b == 1 && c == 1 && d == 1 && " \
2012 "e == 1 && f == 1 && g == 1 && h == 1"
2013 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, ""),
2014 DATA_REC(NO, 0, 1, 1, 1, 1, 1, 1, 1, "bcdefgh"),
2015 DATA_REC(NO, 1, 1, 1, 1, 1, 1, 1, 0, ""),
2016 #undef FILTER
2017 #define FILTER "a == 1 || b == 1 || c == 1 || d == 1 || " \
2018 "e == 1 || f == 1 || g == 1 || h == 1"
2019 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 0, ""),
2020 DATA_REC(YES, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2021 DATA_REC(YES, 1, 0, 0, 0, 0, 0, 0, 0, "bcdefgh"),
2022 #undef FILTER
2023 #define FILTER "(a == 1 || b == 1) && (c == 1 || d == 1) && " \
2024 "(e == 1 || f == 1) && (g == 1 || h == 1)"
2025 DATA_REC(NO, 0, 0, 1, 1, 1, 1, 1, 1, "dfh"),
2026 DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2027 DATA_REC(YES, 1, 0, 1, 0, 0, 1, 0, 1, "bd"),
2028 DATA_REC(NO, 1, 0, 1, 0, 0, 1, 0, 0, "bd"),
2029 #undef FILTER
2030 #define FILTER "(a == 1 && b == 1) || (c == 1 && d == 1) || " \
2031 "(e == 1 && f == 1) || (g == 1 && h == 1)"
2032 DATA_REC(YES, 1, 0, 1, 1, 1, 1, 1, 1, "efgh"),
2033 DATA_REC(YES, 0, 0, 0, 0, 0, 0, 1, 1, ""),
2034 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2035 #undef FILTER
2036 #define FILTER "(a == 1 && b == 1) && (c == 1 && d == 1) && " \
2037 "(e == 1 && f == 1) || (g == 1 && h == 1)"
2038 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 0, "gh"),
2039 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2040 DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, ""),
2041 #undef FILTER
2042 #define FILTER "((a == 1 || b == 1) || (c == 1 || d == 1) || " \
2043 "(e == 1 || f == 1)) && (g == 1 || h == 1)"
2044 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 1, "bcdef"),
2045 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 0, ""),
2046 DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, "h"),
2047 #undef FILTER
2048 #define FILTER "((((((((a == 1) && (b == 1)) || (c == 1)) && (d == 1)) || " \
2049 "(e == 1)) && (f == 1)) || (g == 1)) && (h == 1))"
2050 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "ceg"),
2051 DATA_REC(NO, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2052 DATA_REC(NO, 1, 0, 1, 0, 1, 0, 1, 0, ""),
2053 #undef FILTER
2054 #define FILTER "((((((((a == 1) || (b == 1)) && (c == 1)) || (d == 1)) && " \
2055 "(e == 1)) || (f == 1)) && (g == 1)) || (h == 1))"
2056 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "bdfh"),
2057 DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2058 DATA_REC(YES, 1, 0, 1, 0, 1, 0, 1, 0, "bdfh"),
2059 };
2060
2061 #undef DATA_REC
2062 #undef FILTER
2063 #undef YES
2064 #undef NO
2065
2066 #define DATA_CNT (sizeof(test_filter_data)/sizeof(struct test_filter_data_t))
2067
2068 static int test_pred_visited;
2069
2070 static int test_pred_visited_fn(struct filter_pred *pred, void *event)
2071 {
2072 struct ftrace_event_field *field = pred->field;
2073
2074 test_pred_visited = 1;
2075 printk(KERN_INFO "\npred visited %s\n", field->name);
2076 return 1;
2077 }
2078
2079 static int test_walk_pred_cb(enum move_type move, struct filter_pred *pred,
2080 int *err, void *data)
2081 {
2082 char *fields = data;
2083
2084 if ((move == MOVE_DOWN) &&
2085 (pred->left == FILTER_PRED_INVALID)) {
2086 struct ftrace_event_field *field = pred->field;
2087
2088 if (!field) {
2089 WARN(1, "all leafs should have field defined");
2090 return WALK_PRED_DEFAULT;
2091 }
2092 if (!strchr(fields, *field->name))
2093 return WALK_PRED_DEFAULT;
2094
2095 WARN_ON(!pred->fn);
2096 pred->fn = test_pred_visited_fn;
2097 }
2098 return WALK_PRED_DEFAULT;
2099 }
2100
2101 static __init int ftrace_test_event_filter(void)
2102 {
2103 int i;
2104
2105 printk(KERN_INFO "Testing ftrace filter: ");
2106
2107 for (i = 0; i < DATA_CNT; i++) {
2108 struct event_filter *filter = NULL;
2109 struct test_filter_data_t *d = &test_filter_data[i];
2110 int err;
2111
2112 err = create_filter(&event_ftrace_test_filter, d->filter,
2113 false, &filter);
2114 if (err) {
2115 printk(KERN_INFO
2116 "Failed to get filter for '%s', err %d\n",
2117 d->filter, err);
2118 __free_filter(filter);
2119 break;
2120 }
2121
2122 /*
2123 * The preemption disabling is not really needed for self
2124 * tests, but the rcu dereference will complain without it.
2125 */
2126 preempt_disable();
2127 if (*d->not_visited)
2128 walk_pred_tree(filter->preds, filter->root,
2129 test_walk_pred_cb,
2130 d->not_visited);
2131
2132 test_pred_visited = 0;
2133 err = filter_match_preds(filter, &d->rec);
2134 preempt_enable();
2135
2136 __free_filter(filter);
2137
2138 if (test_pred_visited) {
2139 printk(KERN_INFO
2140 "Failed, unwanted pred visited for filter %s\n",
2141 d->filter);
2142 break;
2143 }
2144
2145 if (err != d->match) {
2146 printk(KERN_INFO
2147 "Failed to match filter '%s', expected %d\n",
2148 d->filter, d->match);
2149 break;
2150 }
2151 }
2152
2153 if (i == DATA_CNT)
2154 printk(KERN_CONT "OK\n");
2155
2156 return 0;
2157 }
2158
2159 late_initcall(ftrace_test_event_filter);
2160
2161 #endif /* CONFIG_FTRACE_STARTUP_TEST */
Linux kernel - Deliverables
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