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-rw-r--r--kernel/trace/ftrace.c1727
1 files changed, 1727 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
new file mode 100644
index 000000000000..4231a3dc224a
--- /dev/null
+++ b/kernel/trace/ftrace.c
@@ -0,0 +1,1727 @@
1/*
2 * Infrastructure for profiling code inserted by 'gcc -pg'.
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code in the latency_tracer, that is:
11 *
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
14 */
15
16#include <linux/stop_machine.h>
17#include <linux/clocksource.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/debugfs.h>
21#include <linux/hardirq.h>
22#include <linux/kthread.h>
23#include <linux/uaccess.h>
24#include <linux/kprobes.h>
25#include <linux/ftrace.h>
26#include <linux/sysctl.h>
27#include <linux/ctype.h>
28#include <linux/hash.h>
29#include <linux/list.h>
30
31#include <asm/ftrace.h>
32
33#include "trace.h"
34
35/* ftrace_enabled is a method to turn ftrace on or off */
36int ftrace_enabled __read_mostly;
37static int last_ftrace_enabled;
38
39/*
40 * ftrace_disabled is set when an anomaly is discovered.
41 * ftrace_disabled is much stronger than ftrace_enabled.
42 */
43static int ftrace_disabled __read_mostly;
44
45static DEFINE_SPINLOCK(ftrace_lock);
46static DEFINE_MUTEX(ftrace_sysctl_lock);
47
48static struct ftrace_ops ftrace_list_end __read_mostly =
49{
50 .func = ftrace_stub,
51};
52
53static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
54ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
55
56static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
57{
58 struct ftrace_ops *op = ftrace_list;
59
60 /* in case someone actually ports this to alpha! */
61 read_barrier_depends();
62
63 while (op != &ftrace_list_end) {
64 /* silly alpha */
65 read_barrier_depends();
66 op->func(ip, parent_ip);
67 op = op->next;
68 };
69}
70
71/**
72 * clear_ftrace_function - reset the ftrace function
73 *
74 * This NULLs the ftrace function and in essence stops
75 * tracing. There may be lag
76 */
77void clear_ftrace_function(void)
78{
79 ftrace_trace_function = ftrace_stub;
80}
81
82static int __register_ftrace_function(struct ftrace_ops *ops)
83{
84 /* Should never be called by interrupts */
85 spin_lock(&ftrace_lock);
86
87 ops->next = ftrace_list;
88 /*
89 * We are entering ops into the ftrace_list but another
90 * CPU might be walking that list. We need to make sure
91 * the ops->next pointer is valid before another CPU sees
92 * the ops pointer included into the ftrace_list.
93 */
94 smp_wmb();
95 ftrace_list = ops;
96
97 if (ftrace_enabled) {
98 /*
99 * For one func, simply call it directly.
100 * For more than one func, call the chain.
101 */
102 if (ops->next == &ftrace_list_end)
103 ftrace_trace_function = ops->func;
104 else
105 ftrace_trace_function = ftrace_list_func;
106 }
107
108 spin_unlock(&ftrace_lock);
109
110 return 0;
111}
112
113static int __unregister_ftrace_function(struct ftrace_ops *ops)
114{
115 struct ftrace_ops **p;
116 int ret = 0;
117
118 spin_lock(&ftrace_lock);
119
120 /*
121 * If we are removing the last function, then simply point
122 * to the ftrace_stub.
123 */
124 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
125 ftrace_trace_function = ftrace_stub;
126 ftrace_list = &ftrace_list_end;
127 goto out;
128 }
129
130 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
131 if (*p == ops)
132 break;
133
134 if (*p != ops) {
135 ret = -1;
136 goto out;
137 }
138
139 *p = (*p)->next;
140
141 if (ftrace_enabled) {
142 /* If we only have one func left, then call that directly */
143 if (ftrace_list == &ftrace_list_end ||
144 ftrace_list->next == &ftrace_list_end)
145 ftrace_trace_function = ftrace_list->func;
146 }
147
148 out:
149 spin_unlock(&ftrace_lock);
150
151 return ret;
152}
153
154#ifdef CONFIG_DYNAMIC_FTRACE
155
156static struct task_struct *ftraced_task;
157
158enum {
159 FTRACE_ENABLE_CALLS = (1 << 0),
160 FTRACE_DISABLE_CALLS = (1 << 1),
161 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
162 FTRACE_ENABLE_MCOUNT = (1 << 3),
163 FTRACE_DISABLE_MCOUNT = (1 << 4),
164};
165
166static int ftrace_filtered;
167static int tracing_on;
168static int frozen_record_count;
169
170static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
171
172static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
173
174static DEFINE_SPINLOCK(ftrace_shutdown_lock);
175static DEFINE_MUTEX(ftraced_lock);
176static DEFINE_MUTEX(ftrace_regex_lock);
177
178struct ftrace_page {
179 struct ftrace_page *next;
180 unsigned long index;
181 struct dyn_ftrace records[];
182};
183
184#define ENTRIES_PER_PAGE \
185 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
186
187/* estimate from running different kernels */
188#define NR_TO_INIT 10000
189
190static struct ftrace_page *ftrace_pages_start;
191static struct ftrace_page *ftrace_pages;
192
193static int ftraced_trigger;
194static int ftraced_suspend;
195static int ftraced_stop;
196
197static int ftrace_record_suspend;
198
199static struct dyn_ftrace *ftrace_free_records;
200
201
202#ifdef CONFIG_KPROBES
203static inline void freeze_record(struct dyn_ftrace *rec)
204{
205 if (!(rec->flags & FTRACE_FL_FROZEN)) {
206 rec->flags |= FTRACE_FL_FROZEN;
207 frozen_record_count++;
208 }
209}
210
211static inline void unfreeze_record(struct dyn_ftrace *rec)
212{
213 if (rec->flags & FTRACE_FL_FROZEN) {
214 rec->flags &= ~FTRACE_FL_FROZEN;
215 frozen_record_count--;
216 }
217}
218
219static inline int record_frozen(struct dyn_ftrace *rec)
220{
221 return rec->flags & FTRACE_FL_FROZEN;
222}
223#else
224# define freeze_record(rec) ({ 0; })
225# define unfreeze_record(rec) ({ 0; })
226# define record_frozen(rec) ({ 0; })
227#endif /* CONFIG_KPROBES */
228
229int skip_trace(unsigned long ip)
230{
231 unsigned long fl;
232 struct dyn_ftrace *rec;
233 struct hlist_node *t;
234 struct hlist_head *head;
235
236 if (frozen_record_count == 0)
237 return 0;
238
239 head = &ftrace_hash[hash_long(ip, FTRACE_HASHBITS)];
240 hlist_for_each_entry_rcu(rec, t, head, node) {
241 if (rec->ip == ip) {
242 if (record_frozen(rec)) {
243 if (rec->flags & FTRACE_FL_FAILED)
244 return 1;
245
246 if (!(rec->flags & FTRACE_FL_CONVERTED))
247 return 1;
248
249 if (!tracing_on || !ftrace_enabled)
250 return 1;
251
252 if (ftrace_filtered) {
253 fl = rec->flags & (FTRACE_FL_FILTER |
254 FTRACE_FL_NOTRACE);
255 if (!fl || (fl & FTRACE_FL_NOTRACE))
256 return 1;
257 }
258 }
259 break;
260 }
261 }
262
263 return 0;
264}
265
266static inline int
267ftrace_ip_in_hash(unsigned long ip, unsigned long key)
268{
269 struct dyn_ftrace *p;
270 struct hlist_node *t;
271 int found = 0;
272
273 hlist_for_each_entry_rcu(p, t, &ftrace_hash[key], node) {
274 if (p->ip == ip) {
275 found = 1;
276 break;
277 }
278 }
279
280 return found;
281}
282
283static inline void
284ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
285{
286 hlist_add_head_rcu(&node->node, &ftrace_hash[key]);
287}
288
289/* called from kstop_machine */
290static inline void ftrace_del_hash(struct dyn_ftrace *node)
291{
292 hlist_del(&node->node);
293}
294
295static void ftrace_free_rec(struct dyn_ftrace *rec)
296{
297 /* no locking, only called from kstop_machine */
298
299 rec->ip = (unsigned long)ftrace_free_records;
300 ftrace_free_records = rec;
301 rec->flags |= FTRACE_FL_FREE;
302}
303
304static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
305{
306 struct dyn_ftrace *rec;
307
308 /* First check for freed records */
309 if (ftrace_free_records) {
310 rec = ftrace_free_records;
311
312 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
313 WARN_ON_ONCE(1);
314 ftrace_free_records = NULL;
315 ftrace_disabled = 1;
316 ftrace_enabled = 0;
317 return NULL;
318 }
319
320 ftrace_free_records = (void *)rec->ip;
321 memset(rec, 0, sizeof(*rec));
322 return rec;
323 }
324
325 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
326 if (!ftrace_pages->next)
327 return NULL;
328 ftrace_pages = ftrace_pages->next;
329 }
330
331 return &ftrace_pages->records[ftrace_pages->index++];
332}
333
334static void
335ftrace_record_ip(unsigned long ip)
336{
337 struct dyn_ftrace *node;
338 unsigned long flags;
339 unsigned long key;
340 int resched;
341 int atomic;
342 int cpu;
343
344 if (!ftrace_enabled || ftrace_disabled)
345 return;
346
347 resched = need_resched();
348 preempt_disable_notrace();
349
350 /*
351 * We simply need to protect against recursion.
352 * Use the the raw version of smp_processor_id and not
353 * __get_cpu_var which can call debug hooks that can
354 * cause a recursive crash here.
355 */
356 cpu = raw_smp_processor_id();
357 per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
358 if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1)
359 goto out;
360
361 if (unlikely(ftrace_record_suspend))
362 goto out;
363
364 key = hash_long(ip, FTRACE_HASHBITS);
365
366 WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
367
368 if (ftrace_ip_in_hash(ip, key))
369 goto out;
370
371 atomic = irqs_disabled();
372
373 spin_lock_irqsave(&ftrace_shutdown_lock, flags);
374
375 /* This ip may have hit the hash before the lock */
376 if (ftrace_ip_in_hash(ip, key))
377 goto out_unlock;
378
379 node = ftrace_alloc_dyn_node(ip);
380 if (!node)
381 goto out_unlock;
382
383 node->ip = ip;
384
385 ftrace_add_hash(node, key);
386
387 ftraced_trigger = 1;
388
389 out_unlock:
390 spin_unlock_irqrestore(&ftrace_shutdown_lock, flags);
391 out:
392 per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
393
394 /* prevent recursion with scheduler */
395 if (resched)
396 preempt_enable_no_resched_notrace();
397 else
398 preempt_enable_notrace();
399}
400
401#define FTRACE_ADDR ((long)(ftrace_caller))
402
403static int
404__ftrace_replace_code(struct dyn_ftrace *rec,
405 unsigned char *old, unsigned char *new, int enable)
406{
407 unsigned long ip, fl;
408
409 ip = rec->ip;
410
411 if (ftrace_filtered && enable) {
412 /*
413 * If filtering is on:
414 *
415 * If this record is set to be filtered and
416 * is enabled then do nothing.
417 *
418 * If this record is set to be filtered and
419 * it is not enabled, enable it.
420 *
421 * If this record is not set to be filtered
422 * and it is not enabled do nothing.
423 *
424 * If this record is set not to trace then
425 * do nothing.
426 *
427 * If this record is set not to trace and
428 * it is enabled then disable it.
429 *
430 * If this record is not set to be filtered and
431 * it is enabled, disable it.
432 */
433
434 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
435 FTRACE_FL_ENABLED);
436
437 if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
438 (fl == (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
439 !fl || (fl == FTRACE_FL_NOTRACE))
440 return 0;
441
442 /*
443 * If it is enabled disable it,
444 * otherwise enable it!
445 */
446 if (fl & FTRACE_FL_ENABLED) {
447 /* swap new and old */
448 new = old;
449 old = ftrace_call_replace(ip, FTRACE_ADDR);
450 rec->flags &= ~FTRACE_FL_ENABLED;
451 } else {
452 new = ftrace_call_replace(ip, FTRACE_ADDR);
453 rec->flags |= FTRACE_FL_ENABLED;
454 }
455 } else {
456
457 if (enable) {
458 /*
459 * If this record is set not to trace and is
460 * not enabled, do nothing.
461 */
462 fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
463 if (fl == FTRACE_FL_NOTRACE)
464 return 0;
465
466 new = ftrace_call_replace(ip, FTRACE_ADDR);
467 } else
468 old = ftrace_call_replace(ip, FTRACE_ADDR);
469
470 if (enable) {
471 if (rec->flags & FTRACE_FL_ENABLED)
472 return 0;
473 rec->flags |= FTRACE_FL_ENABLED;
474 } else {
475 if (!(rec->flags & FTRACE_FL_ENABLED))
476 return 0;
477 rec->flags &= ~FTRACE_FL_ENABLED;
478 }
479 }
480
481 return ftrace_modify_code(ip, old, new);
482}
483
484static void ftrace_replace_code(int enable)
485{
486 int i, failed;
487 unsigned char *new = NULL, *old = NULL;
488 struct dyn_ftrace *rec;
489 struct ftrace_page *pg;
490
491 if (enable)
492 old = ftrace_nop_replace();
493 else
494 new = ftrace_nop_replace();
495
496 for (pg = ftrace_pages_start; pg; pg = pg->next) {
497 for (i = 0; i < pg->index; i++) {
498 rec = &pg->records[i];
499
500 /* don't modify code that has already faulted */
501 if (rec->flags & FTRACE_FL_FAILED)
502 continue;
503
504 /* ignore updates to this record's mcount site */
505 if (get_kprobe((void *)rec->ip)) {
506 freeze_record(rec);
507 continue;
508 } else {
509 unfreeze_record(rec);
510 }
511
512 failed = __ftrace_replace_code(rec, old, new, enable);
513 if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
514 rec->flags |= FTRACE_FL_FAILED;
515 if ((system_state == SYSTEM_BOOTING) ||
516 !core_kernel_text(rec->ip)) {
517 ftrace_del_hash(rec);
518 ftrace_free_rec(rec);
519 }
520 }
521 }
522 }
523}
524
525static void ftrace_shutdown_replenish(void)
526{
527 if (ftrace_pages->next)
528 return;
529
530 /* allocate another page */
531 ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
532}
533
534static int
535ftrace_code_disable(struct dyn_ftrace *rec)
536{
537 unsigned long ip;
538 unsigned char *nop, *call;
539 int failed;
540
541 ip = rec->ip;
542
543 nop = ftrace_nop_replace();
544 call = ftrace_call_replace(ip, MCOUNT_ADDR);
545
546 failed = ftrace_modify_code(ip, call, nop);
547 if (failed) {
548 rec->flags |= FTRACE_FL_FAILED;
549 return 0;
550 }
551 return 1;
552}
553
554static int __ftrace_update_code(void *ignore);
555
556static int __ftrace_modify_code(void *data)
557{
558 unsigned long addr;
559 int *command = data;
560
561 if (*command & FTRACE_ENABLE_CALLS) {
562 /*
563 * Update any recorded ips now that we have the
564 * machine stopped
565 */
566 __ftrace_update_code(NULL);
567 ftrace_replace_code(1);
568 tracing_on = 1;
569 } else if (*command & FTRACE_DISABLE_CALLS) {
570 ftrace_replace_code(0);
571 tracing_on = 0;
572 }
573
574 if (*command & FTRACE_UPDATE_TRACE_FUNC)
575 ftrace_update_ftrace_func(ftrace_trace_function);
576
577 if (*command & FTRACE_ENABLE_MCOUNT) {
578 addr = (unsigned long)ftrace_record_ip;
579 ftrace_mcount_set(&addr);
580 } else if (*command & FTRACE_DISABLE_MCOUNT) {
581 addr = (unsigned long)ftrace_stub;
582 ftrace_mcount_set(&addr);
583 }
584
585 return 0;
586}
587
588static void ftrace_run_update_code(int command)
589{
590 stop_machine_run(__ftrace_modify_code, &command, NR_CPUS);
591}
592
593void ftrace_disable_daemon(void)
594{
595 /* Stop the daemon from calling kstop_machine */
596 mutex_lock(&ftraced_lock);
597 ftraced_stop = 1;
598 mutex_unlock(&ftraced_lock);
599
600 ftrace_force_update();
601}
602
603void ftrace_enable_daemon(void)
604{
605 mutex_lock(&ftraced_lock);
606 ftraced_stop = 0;
607 mutex_unlock(&ftraced_lock);
608
609 ftrace_force_update();
610}
611
612static ftrace_func_t saved_ftrace_func;
613
614static void ftrace_startup(void)
615{
616 int command = 0;
617
618 if (unlikely(ftrace_disabled))
619 return;
620
621 mutex_lock(&ftraced_lock);
622 ftraced_suspend++;
623 if (ftraced_suspend == 1)
624 command |= FTRACE_ENABLE_CALLS;
625
626 if (saved_ftrace_func != ftrace_trace_function) {
627 saved_ftrace_func = ftrace_trace_function;
628 command |= FTRACE_UPDATE_TRACE_FUNC;
629 }
630
631 if (!command || !ftrace_enabled)
632 goto out;
633
634 ftrace_run_update_code(command);
635 out:
636 mutex_unlock(&ftraced_lock);
637}
638
639static void ftrace_shutdown(void)
640{
641 int command = 0;
642
643 if (unlikely(ftrace_disabled))
644 return;
645
646 mutex_lock(&ftraced_lock);
647 ftraced_suspend--;
648 if (!ftraced_suspend)
649 command |= FTRACE_DISABLE_CALLS;
650
651 if (saved_ftrace_func != ftrace_trace_function) {
652 saved_ftrace_func = ftrace_trace_function;
653 command |= FTRACE_UPDATE_TRACE_FUNC;
654 }
655
656 if (!command || !ftrace_enabled)
657 goto out;
658
659 ftrace_run_update_code(command);
660 out:
661 mutex_unlock(&ftraced_lock);
662}
663
664static void ftrace_startup_sysctl(void)
665{
666 int command = FTRACE_ENABLE_MCOUNT;
667
668 if (unlikely(ftrace_disabled))
669 return;
670
671 mutex_lock(&ftraced_lock);
672 /* Force update next time */
673 saved_ftrace_func = NULL;
674 /* ftraced_suspend is true if we want ftrace running */
675 if (ftraced_suspend)
676 command |= FTRACE_ENABLE_CALLS;
677
678 ftrace_run_update_code(command);
679 mutex_unlock(&ftraced_lock);
680}
681
682static void ftrace_shutdown_sysctl(void)
683{
684 int command = FTRACE_DISABLE_MCOUNT;
685
686 if (unlikely(ftrace_disabled))
687 return;
688
689 mutex_lock(&ftraced_lock);
690 /* ftraced_suspend is true if ftrace is running */
691 if (ftraced_suspend)
692 command |= FTRACE_DISABLE_CALLS;
693
694 ftrace_run_update_code(command);
695 mutex_unlock(&ftraced_lock);
696}
697
698static cycle_t ftrace_update_time;
699static unsigned long ftrace_update_cnt;
700unsigned long ftrace_update_tot_cnt;
701
702static int __ftrace_update_code(void *ignore)
703{
704 int i, save_ftrace_enabled;
705 cycle_t start, stop;
706 struct dyn_ftrace *p;
707 struct hlist_node *t, *n;
708 struct hlist_head *head, temp_list;
709
710 /* Don't be recording funcs now */
711 ftrace_record_suspend++;
712 save_ftrace_enabled = ftrace_enabled;
713 ftrace_enabled = 0;
714
715 start = ftrace_now(raw_smp_processor_id());
716 ftrace_update_cnt = 0;
717
718 /* No locks needed, the machine is stopped! */
719 for (i = 0; i < FTRACE_HASHSIZE; i++) {
720 INIT_HLIST_HEAD(&temp_list);
721 head = &ftrace_hash[i];
722
723 /* all CPUS are stopped, we are safe to modify code */
724 hlist_for_each_entry_safe(p, t, n, head, node) {
725 /* Skip over failed records which have not been
726 * freed. */
727 if (p->flags & FTRACE_FL_FAILED)
728 continue;
729
730 /* Unconverted records are always at the head of the
731 * hash bucket. Once we encounter a converted record,
732 * simply skip over to the next bucket. Saves ftraced
733 * some processor cycles (ftrace does its bid for
734 * global warming :-p ). */
735 if (p->flags & (FTRACE_FL_CONVERTED))
736 break;
737
738 /* Ignore updates to this record's mcount site.
739 * Reintroduce this record at the head of this
740 * bucket to attempt to "convert" it again if
741 * the kprobe on it is unregistered before the
742 * next run. */
743 if (get_kprobe((void *)p->ip)) {
744 ftrace_del_hash(p);
745 INIT_HLIST_NODE(&p->node);
746 hlist_add_head(&p->node, &temp_list);
747 freeze_record(p);
748 continue;
749 } else {
750 unfreeze_record(p);
751 }
752
753 /* convert record (i.e, patch mcount-call with NOP) */
754 if (ftrace_code_disable(p)) {
755 p->flags |= FTRACE_FL_CONVERTED;
756 ftrace_update_cnt++;
757 } else {
758 if ((system_state == SYSTEM_BOOTING) ||
759 !core_kernel_text(p->ip)) {
760 ftrace_del_hash(p);
761 ftrace_free_rec(p);
762 }
763 }
764 }
765
766 hlist_for_each_entry_safe(p, t, n, &temp_list, node) {
767 hlist_del(&p->node);
768 INIT_HLIST_NODE(&p->node);
769 hlist_add_head(&p->node, head);
770 }
771 }
772
773 stop = ftrace_now(raw_smp_processor_id());
774 ftrace_update_time = stop - start;
775 ftrace_update_tot_cnt += ftrace_update_cnt;
776 ftraced_trigger = 0;
777
778 ftrace_enabled = save_ftrace_enabled;
779 ftrace_record_suspend--;
780
781 return 0;
782}
783
784static int ftrace_update_code(void)
785{
786 if (unlikely(ftrace_disabled) ||
787 !ftrace_enabled || !ftraced_trigger)
788 return 0;
789
790 stop_machine_run(__ftrace_update_code, NULL, NR_CPUS);
791
792 return 1;
793}
794
795static int ftraced(void *ignore)
796{
797 unsigned long usecs;
798
799 while (!kthread_should_stop()) {
800
801 set_current_state(TASK_INTERRUPTIBLE);
802
803 /* check once a second */
804 schedule_timeout(HZ);
805
806 if (unlikely(ftrace_disabled))
807 continue;
808
809 mutex_lock(&ftrace_sysctl_lock);
810 mutex_lock(&ftraced_lock);
811 if (!ftraced_suspend && !ftraced_stop &&
812 ftrace_update_code()) {
813 usecs = nsecs_to_usecs(ftrace_update_time);
814 if (ftrace_update_tot_cnt > 100000) {
815 ftrace_update_tot_cnt = 0;
816 pr_info("hm, dftrace overflow: %lu change%s"
817 " (%lu total) in %lu usec%s\n",
818 ftrace_update_cnt,
819 ftrace_update_cnt != 1 ? "s" : "",
820 ftrace_update_tot_cnt,
821 usecs, usecs != 1 ? "s" : "");
822 ftrace_disabled = 1;
823 WARN_ON_ONCE(1);
824 }
825 }
826 mutex_unlock(&ftraced_lock);
827 mutex_unlock(&ftrace_sysctl_lock);
828
829 ftrace_shutdown_replenish();
830 }
831 __set_current_state(TASK_RUNNING);
832 return 0;
833}
834
835static int __init ftrace_dyn_table_alloc(void)
836{
837 struct ftrace_page *pg;
838 int cnt;
839 int i;
840
841 /* allocate a few pages */
842 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
843 if (!ftrace_pages_start)
844 return -1;
845
846 /*
847 * Allocate a few more pages.
848 *
849 * TODO: have some parser search vmlinux before
850 * final linking to find all calls to ftrace.
851 * Then we can:
852 * a) know how many pages to allocate.
853 * and/or
854 * b) set up the table then.
855 *
856 * The dynamic code is still necessary for
857 * modules.
858 */
859
860 pg = ftrace_pages = ftrace_pages_start;
861
862 cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
863
864 for (i = 0; i < cnt; i++) {
865 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
866
867 /* If we fail, we'll try later anyway */
868 if (!pg->next)
869 break;
870
871 pg = pg->next;
872 }
873
874 return 0;
875}
876
877enum {
878 FTRACE_ITER_FILTER = (1 << 0),
879 FTRACE_ITER_CONT = (1 << 1),
880 FTRACE_ITER_NOTRACE = (1 << 2),
881 FTRACE_ITER_FAILURES = (1 << 3),
882};
883
884#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
885
886struct ftrace_iterator {
887 loff_t pos;
888 struct ftrace_page *pg;
889 unsigned idx;
890 unsigned flags;
891 unsigned char buffer[FTRACE_BUFF_MAX+1];
892 unsigned buffer_idx;
893 unsigned filtered;
894};
895
896static void *
897t_next(struct seq_file *m, void *v, loff_t *pos)
898{
899 struct ftrace_iterator *iter = m->private;
900 struct dyn_ftrace *rec = NULL;
901
902 (*pos)++;
903
904 retry:
905 if (iter->idx >= iter->pg->index) {
906 if (iter->pg->next) {
907 iter->pg = iter->pg->next;
908 iter->idx = 0;
909 goto retry;
910 }
911 } else {
912 rec = &iter->pg->records[iter->idx++];
913 if ((!(iter->flags & FTRACE_ITER_FAILURES) &&
914 (rec->flags & FTRACE_FL_FAILED)) ||
915
916 ((iter->flags & FTRACE_ITER_FAILURES) &&
917 (!(rec->flags & FTRACE_FL_FAILED) ||
918 (rec->flags & FTRACE_FL_FREE))) ||
919
920 ((iter->flags & FTRACE_ITER_FILTER) &&
921 !(rec->flags & FTRACE_FL_FILTER)) ||
922
923 ((iter->flags & FTRACE_ITER_NOTRACE) &&
924 !(rec->flags & FTRACE_FL_NOTRACE))) {
925 rec = NULL;
926 goto retry;
927 }
928 }
929
930 iter->pos = *pos;
931
932 return rec;
933}
934
935static void *t_start(struct seq_file *m, loff_t *pos)
936{
937 struct ftrace_iterator *iter = m->private;
938 void *p = NULL;
939 loff_t l = -1;
940
941 if (*pos != iter->pos) {
942 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
943 ;
944 } else {
945 l = *pos;
946 p = t_next(m, p, &l);
947 }
948
949 return p;
950}
951
952static void t_stop(struct seq_file *m, void *p)
953{
954}
955
956static int t_show(struct seq_file *m, void *v)
957{
958 struct dyn_ftrace *rec = v;
959 char str[KSYM_SYMBOL_LEN];
960
961 if (!rec)
962 return 0;
963
964 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
965
966 seq_printf(m, "%s\n", str);
967
968 return 0;
969}
970
971static struct seq_operations show_ftrace_seq_ops = {
972 .start = t_start,
973 .next = t_next,
974 .stop = t_stop,
975 .show = t_show,
976};
977
978static int
979ftrace_avail_open(struct inode *inode, struct file *file)
980{
981 struct ftrace_iterator *iter;
982 int ret;
983
984 if (unlikely(ftrace_disabled))
985 return -ENODEV;
986
987 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
988 if (!iter)
989 return -ENOMEM;
990
991 iter->pg = ftrace_pages_start;
992 iter->pos = -1;
993
994 ret = seq_open(file, &show_ftrace_seq_ops);
995 if (!ret) {
996 struct seq_file *m = file->private_data;
997
998 m->private = iter;
999 } else {
1000 kfree(iter);
1001 }
1002
1003 return ret;
1004}
1005
1006int ftrace_avail_release(struct inode *inode, struct file *file)
1007{
1008 struct seq_file *m = (struct seq_file *)file->private_data;
1009 struct ftrace_iterator *iter = m->private;
1010
1011 seq_release(inode, file);
1012 kfree(iter);
1013
1014 return 0;
1015}
1016
1017static int
1018ftrace_failures_open(struct inode *inode, struct file *file)
1019{
1020 int ret;
1021 struct seq_file *m;
1022 struct ftrace_iterator *iter;
1023
1024 ret = ftrace_avail_open(inode, file);
1025 if (!ret) {
1026 m = (struct seq_file *)file->private_data;
1027 iter = (struct ftrace_iterator *)m->private;
1028 iter->flags = FTRACE_ITER_FAILURES;
1029 }
1030
1031 return ret;
1032}
1033
1034
1035static void ftrace_filter_reset(int enable)
1036{
1037 struct ftrace_page *pg;
1038 struct dyn_ftrace *rec;
1039 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1040 unsigned i;
1041
1042 /* keep kstop machine from running */
1043 preempt_disable();
1044 if (enable)
1045 ftrace_filtered = 0;
1046 pg = ftrace_pages_start;
1047 while (pg) {
1048 for (i = 0; i < pg->index; i++) {
1049 rec = &pg->records[i];
1050 if (rec->flags & FTRACE_FL_FAILED)
1051 continue;
1052 rec->flags &= ~type;
1053 }
1054 pg = pg->next;
1055 }
1056 preempt_enable();
1057}
1058
1059static int
1060ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1061{
1062 struct ftrace_iterator *iter;
1063 int ret = 0;
1064
1065 if (unlikely(ftrace_disabled))
1066 return -ENODEV;
1067
1068 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1069 if (!iter)
1070 return -ENOMEM;
1071
1072 mutex_lock(&ftrace_regex_lock);
1073 if ((file->f_mode & FMODE_WRITE) &&
1074 !(file->f_flags & O_APPEND))
1075 ftrace_filter_reset(enable);
1076
1077 if (file->f_mode & FMODE_READ) {
1078 iter->pg = ftrace_pages_start;
1079 iter->pos = -1;
1080 iter->flags = enable ? FTRACE_ITER_FILTER :
1081 FTRACE_ITER_NOTRACE;
1082
1083 ret = seq_open(file, &show_ftrace_seq_ops);
1084 if (!ret) {
1085 struct seq_file *m = file->private_data;
1086 m->private = iter;
1087 } else
1088 kfree(iter);
1089 } else
1090 file->private_data = iter;
1091 mutex_unlock(&ftrace_regex_lock);
1092
1093 return ret;
1094}
1095
1096static int
1097ftrace_filter_open(struct inode *inode, struct file *file)
1098{
1099 return ftrace_regex_open(inode, file, 1);
1100}
1101
1102static int
1103ftrace_notrace_open(struct inode *inode, struct file *file)
1104{
1105 return ftrace_regex_open(inode, file, 0);
1106}
1107
1108static ssize_t
1109ftrace_regex_read(struct file *file, char __user *ubuf,
1110 size_t cnt, loff_t *ppos)
1111{
1112 if (file->f_mode & FMODE_READ)
1113 return seq_read(file, ubuf, cnt, ppos);
1114 else
1115 return -EPERM;
1116}
1117
1118static loff_t
1119ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1120{
1121 loff_t ret;
1122
1123 if (file->f_mode & FMODE_READ)
1124 ret = seq_lseek(file, offset, origin);
1125 else
1126 file->f_pos = ret = 1;
1127
1128 return ret;
1129}
1130
1131enum {
1132 MATCH_FULL,
1133 MATCH_FRONT_ONLY,
1134 MATCH_MIDDLE_ONLY,
1135 MATCH_END_ONLY,
1136};
1137
1138static void
1139ftrace_match(unsigned char *buff, int len, int enable)
1140{
1141 char str[KSYM_SYMBOL_LEN];
1142 char *search = NULL;
1143 struct ftrace_page *pg;
1144 struct dyn_ftrace *rec;
1145 int type = MATCH_FULL;
1146 unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1147 unsigned i, match = 0, search_len = 0;
1148
1149 for (i = 0; i < len; i++) {
1150 if (buff[i] == '*') {
1151 if (!i) {
1152 search = buff + i + 1;
1153 type = MATCH_END_ONLY;
1154 search_len = len - (i + 1);
1155 } else {
1156 if (type == MATCH_END_ONLY) {
1157 type = MATCH_MIDDLE_ONLY;
1158 } else {
1159 match = i;
1160 type = MATCH_FRONT_ONLY;
1161 }
1162 buff[i] = 0;
1163 break;
1164 }
1165 }
1166 }
1167
1168 /* keep kstop machine from running */
1169 preempt_disable();
1170 if (enable)
1171 ftrace_filtered = 1;
1172 pg = ftrace_pages_start;
1173 while (pg) {
1174 for (i = 0; i < pg->index; i++) {
1175 int matched = 0;
1176 char *ptr;
1177
1178 rec = &pg->records[i];
1179 if (rec->flags & FTRACE_FL_FAILED)
1180 continue;
1181 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1182 switch (type) {
1183 case MATCH_FULL:
1184 if (strcmp(str, buff) == 0)
1185 matched = 1;
1186 break;
1187 case MATCH_FRONT_ONLY:
1188 if (memcmp(str, buff, match) == 0)
1189 matched = 1;
1190 break;
1191 case MATCH_MIDDLE_ONLY:
1192 if (strstr(str, search))
1193 matched = 1;
1194 break;
1195 case MATCH_END_ONLY:
1196 ptr = strstr(str, search);
1197 if (ptr && (ptr[search_len] == 0))
1198 matched = 1;
1199 break;
1200 }
1201 if (matched)
1202 rec->flags |= flag;
1203 }
1204 pg = pg->next;
1205 }
1206 preempt_enable();
1207}
1208
1209static ssize_t
1210ftrace_regex_write(struct file *file, const char __user *ubuf,
1211 size_t cnt, loff_t *ppos, int enable)
1212{
1213 struct ftrace_iterator *iter;
1214 char ch;
1215 size_t read = 0;
1216 ssize_t ret;
1217
1218 if (!cnt || cnt < 0)
1219 return 0;
1220
1221 mutex_lock(&ftrace_regex_lock);
1222
1223 if (file->f_mode & FMODE_READ) {
1224 struct seq_file *m = file->private_data;
1225 iter = m->private;
1226 } else
1227 iter = file->private_data;
1228
1229 if (!*ppos) {
1230 iter->flags &= ~FTRACE_ITER_CONT;
1231 iter->buffer_idx = 0;
1232 }
1233
1234 ret = get_user(ch, ubuf++);
1235 if (ret)
1236 goto out;
1237 read++;
1238 cnt--;
1239
1240 if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1241 /* skip white space */
1242 while (cnt && isspace(ch)) {
1243 ret = get_user(ch, ubuf++);
1244 if (ret)
1245 goto out;
1246 read++;
1247 cnt--;
1248 }
1249
1250 if (isspace(ch)) {
1251 file->f_pos += read;
1252 ret = read;
1253 goto out;
1254 }
1255
1256 iter->buffer_idx = 0;
1257 }
1258
1259 while (cnt && !isspace(ch)) {
1260 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1261 iter->buffer[iter->buffer_idx++] = ch;
1262 else {
1263 ret = -EINVAL;
1264 goto out;
1265 }
1266 ret = get_user(ch, ubuf++);
1267 if (ret)
1268 goto out;
1269 read++;
1270 cnt--;
1271 }
1272
1273 if (isspace(ch)) {
1274 iter->filtered++;
1275 iter->buffer[iter->buffer_idx] = 0;
1276 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1277 iter->buffer_idx = 0;
1278 } else
1279 iter->flags |= FTRACE_ITER_CONT;
1280
1281
1282 file->f_pos += read;
1283
1284 ret = read;
1285 out:
1286 mutex_unlock(&ftrace_regex_lock);
1287
1288 return ret;
1289}
1290
1291static ssize_t
1292ftrace_filter_write(struct file *file, const char __user *ubuf,
1293 size_t cnt, loff_t *ppos)
1294{
1295 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1296}
1297
1298static ssize_t
1299ftrace_notrace_write(struct file *file, const char __user *ubuf,
1300 size_t cnt, loff_t *ppos)
1301{
1302 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1303}
1304
1305static void
1306ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1307{
1308 if (unlikely(ftrace_disabled))
1309 return;
1310
1311 mutex_lock(&ftrace_regex_lock);
1312 if (reset)
1313 ftrace_filter_reset(enable);
1314 if (buf)
1315 ftrace_match(buf, len, enable);
1316 mutex_unlock(&ftrace_regex_lock);
1317}
1318
1319/**
1320 * ftrace_set_filter - set a function to filter on in ftrace
1321 * @buf - the string that holds the function filter text.
1322 * @len - the length of the string.
1323 * @reset - non zero to reset all filters before applying this filter.
1324 *
1325 * Filters denote which functions should be enabled when tracing is enabled.
1326 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1327 */
1328void ftrace_set_filter(unsigned char *buf, int len, int reset)
1329{
1330 ftrace_set_regex(buf, len, reset, 1);
1331}
1332
1333/**
1334 * ftrace_set_notrace - set a function to not trace in ftrace
1335 * @buf - the string that holds the function notrace text.
1336 * @len - the length of the string.
1337 * @reset - non zero to reset all filters before applying this filter.
1338 *
1339 * Notrace Filters denote which functions should not be enabled when tracing
1340 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1341 * for tracing.
1342 */
1343void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1344{
1345 ftrace_set_regex(buf, len, reset, 0);
1346}
1347
1348static int
1349ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1350{
1351 struct seq_file *m = (struct seq_file *)file->private_data;
1352 struct ftrace_iterator *iter;
1353
1354 mutex_lock(&ftrace_regex_lock);
1355 if (file->f_mode & FMODE_READ) {
1356 iter = m->private;
1357
1358 seq_release(inode, file);
1359 } else
1360 iter = file->private_data;
1361
1362 if (iter->buffer_idx) {
1363 iter->filtered++;
1364 iter->buffer[iter->buffer_idx] = 0;
1365 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1366 }
1367
1368 mutex_lock(&ftrace_sysctl_lock);
1369 mutex_lock(&ftraced_lock);
1370 if (iter->filtered && ftraced_suspend && ftrace_enabled)
1371 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1372 mutex_unlock(&ftraced_lock);
1373 mutex_unlock(&ftrace_sysctl_lock);
1374
1375 kfree(iter);
1376 mutex_unlock(&ftrace_regex_lock);
1377 return 0;
1378}
1379
1380static int
1381ftrace_filter_release(struct inode *inode, struct file *file)
1382{
1383 return ftrace_regex_release(inode, file, 1);
1384}
1385
1386static int
1387ftrace_notrace_release(struct inode *inode, struct file *file)
1388{
1389 return ftrace_regex_release(inode, file, 0);
1390}
1391
1392static ssize_t
1393ftraced_read(struct file *filp, char __user *ubuf,
1394 size_t cnt, loff_t *ppos)
1395{
1396 /* don't worry about races */
1397 char *buf = ftraced_stop ? "disabled\n" : "enabled\n";
1398 int r = strlen(buf);
1399
1400 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1401}
1402
1403static ssize_t
1404ftraced_write(struct file *filp, const char __user *ubuf,
1405 size_t cnt, loff_t *ppos)
1406{
1407 char buf[64];
1408 long val;
1409 int ret;
1410
1411 if (cnt >= sizeof(buf))
1412 return -EINVAL;
1413
1414 if (copy_from_user(&buf, ubuf, cnt))
1415 return -EFAULT;
1416
1417 if (strncmp(buf, "enable", 6) == 0)
1418 val = 1;
1419 else if (strncmp(buf, "disable", 7) == 0)
1420 val = 0;
1421 else {
1422 buf[cnt] = 0;
1423
1424 ret = strict_strtoul(buf, 10, &val);
1425 if (ret < 0)
1426 return ret;
1427
1428 val = !!val;
1429 }
1430
1431 if (val)
1432 ftrace_enable_daemon();
1433 else
1434 ftrace_disable_daemon();
1435
1436 filp->f_pos += cnt;
1437
1438 return cnt;
1439}
1440
1441static struct file_operations ftrace_avail_fops = {
1442 .open = ftrace_avail_open,
1443 .read = seq_read,
1444 .llseek = seq_lseek,
1445 .release = ftrace_avail_release,
1446};
1447
1448static struct file_operations ftrace_failures_fops = {
1449 .open = ftrace_failures_open,
1450 .read = seq_read,
1451 .llseek = seq_lseek,
1452 .release = ftrace_avail_release,
1453};
1454
1455static struct file_operations ftrace_filter_fops = {
1456 .open = ftrace_filter_open,
1457 .read = ftrace_regex_read,
1458 .write = ftrace_filter_write,
1459 .llseek = ftrace_regex_lseek,
1460 .release = ftrace_filter_release,
1461};
1462
1463static struct file_operations ftrace_notrace_fops = {
1464 .open = ftrace_notrace_open,
1465 .read = ftrace_regex_read,
1466 .write = ftrace_notrace_write,
1467 .llseek = ftrace_regex_lseek,
1468 .release = ftrace_notrace_release,
1469};
1470
1471static struct file_operations ftraced_fops = {
1472 .open = tracing_open_generic,
1473 .read = ftraced_read,
1474 .write = ftraced_write,
1475};
1476
1477/**
1478 * ftrace_force_update - force an update to all recording ftrace functions
1479 */
1480int ftrace_force_update(void)
1481{
1482 int ret = 0;
1483
1484 if (unlikely(ftrace_disabled))
1485 return -ENODEV;
1486
1487 mutex_lock(&ftrace_sysctl_lock);
1488 mutex_lock(&ftraced_lock);
1489
1490 /*
1491 * If ftraced_trigger is not set, then there is nothing
1492 * to update.
1493 */
1494 if (ftraced_trigger && !ftrace_update_code())
1495 ret = -EBUSY;
1496
1497 mutex_unlock(&ftraced_lock);
1498 mutex_unlock(&ftrace_sysctl_lock);
1499
1500 return ret;
1501}
1502
1503static void ftrace_force_shutdown(void)
1504{
1505 struct task_struct *task;
1506 int command = FTRACE_DISABLE_CALLS | FTRACE_UPDATE_TRACE_FUNC;
1507
1508 mutex_lock(&ftraced_lock);
1509 task = ftraced_task;
1510 ftraced_task = NULL;
1511 ftraced_suspend = -1;
1512 ftrace_run_update_code(command);
1513 mutex_unlock(&ftraced_lock);
1514
1515 if (task)
1516 kthread_stop(task);
1517}
1518
1519static __init int ftrace_init_debugfs(void)
1520{
1521 struct dentry *d_tracer;
1522 struct dentry *entry;
1523
1524 d_tracer = tracing_init_dentry();
1525
1526 entry = debugfs_create_file("available_filter_functions", 0444,
1527 d_tracer, NULL, &ftrace_avail_fops);
1528 if (!entry)
1529 pr_warning("Could not create debugfs "
1530 "'available_filter_functions' entry\n");
1531
1532 entry = debugfs_create_file("failures", 0444,
1533 d_tracer, NULL, &ftrace_failures_fops);
1534 if (!entry)
1535 pr_warning("Could not create debugfs 'failures' entry\n");
1536
1537 entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1538 NULL, &ftrace_filter_fops);
1539 if (!entry)
1540 pr_warning("Could not create debugfs "
1541 "'set_ftrace_filter' entry\n");
1542
1543 entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1544 NULL, &ftrace_notrace_fops);
1545 if (!entry)
1546 pr_warning("Could not create debugfs "
1547 "'set_ftrace_notrace' entry\n");
1548
1549 entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer,
1550 NULL, &ftraced_fops);
1551 if (!entry)
1552 pr_warning("Could not create debugfs "
1553 "'ftraced_enabled' entry\n");
1554 return 0;
1555}
1556
1557fs_initcall(ftrace_init_debugfs);
1558
1559static int __init ftrace_dynamic_init(void)
1560{
1561 struct task_struct *p;
1562 unsigned long addr;
1563 int ret;
1564
1565 addr = (unsigned long)ftrace_record_ip;
1566
1567 stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS);
1568
1569 /* ftrace_dyn_arch_init places the return code in addr */
1570 if (addr) {
1571 ret = (int)addr;
1572 goto failed;
1573 }
1574
1575 ret = ftrace_dyn_table_alloc();
1576 if (ret)
1577 goto failed;
1578
1579 p = kthread_run(ftraced, NULL, "ftraced");
1580 if (IS_ERR(p)) {
1581 ret = -1;
1582 goto failed;
1583 }
1584
1585 last_ftrace_enabled = ftrace_enabled = 1;
1586 ftraced_task = p;
1587
1588 return 0;
1589
1590 failed:
1591 ftrace_disabled = 1;
1592 return ret;
1593}
1594
1595core_initcall(ftrace_dynamic_init);
1596#else
1597# define ftrace_startup() do { } while (0)
1598# define ftrace_shutdown() do { } while (0)
1599# define ftrace_startup_sysctl() do { } while (0)
1600# define ftrace_shutdown_sysctl() do { } while (0)
1601# define ftrace_force_shutdown() do { } while (0)
1602#endif /* CONFIG_DYNAMIC_FTRACE */
1603
1604/**
1605 * ftrace_kill_atomic - kill ftrace from critical sections
1606 *
1607 * This function should be used by panic code. It stops ftrace
1608 * but in a not so nice way. If you need to simply kill ftrace
1609 * from a non-atomic section, use ftrace_kill.
1610 */
1611void ftrace_kill_atomic(void)
1612{
1613 ftrace_disabled = 1;
1614 ftrace_enabled = 0;
1615#ifdef CONFIG_DYNAMIC_FTRACE
1616 ftraced_suspend = -1;
1617#endif
1618 clear_ftrace_function();
1619}
1620
1621/**
1622 * ftrace_kill - totally shutdown ftrace
1623 *
1624 * This is a safety measure. If something was detected that seems
1625 * wrong, calling this function will keep ftrace from doing
1626 * any more modifications, and updates.
1627 * used when something went wrong.
1628 */
1629void ftrace_kill(void)
1630{
1631 mutex_lock(&ftrace_sysctl_lock);
1632 ftrace_disabled = 1;
1633 ftrace_enabled = 0;
1634
1635 clear_ftrace_function();
1636 mutex_unlock(&ftrace_sysctl_lock);
1637
1638 /* Try to totally disable ftrace */
1639 ftrace_force_shutdown();
1640}
1641
1642/**
1643 * register_ftrace_function - register a function for profiling
1644 * @ops - ops structure that holds the function for profiling.
1645 *
1646 * Register a function to be called by all functions in the
1647 * kernel.
1648 *
1649 * Note: @ops->func and all the functions it calls must be labeled
1650 * with "notrace", otherwise it will go into a
1651 * recursive loop.
1652 */
1653int register_ftrace_function(struct ftrace_ops *ops)
1654{
1655 int ret;
1656
1657 if (unlikely(ftrace_disabled))
1658 return -1;
1659
1660 mutex_lock(&ftrace_sysctl_lock);
1661 ret = __register_ftrace_function(ops);
1662 ftrace_startup();
1663 mutex_unlock(&ftrace_sysctl_lock);
1664
1665 return ret;
1666}
1667
1668/**
1669 * unregister_ftrace_function - unresgister a function for profiling.
1670 * @ops - ops structure that holds the function to unregister
1671 *
1672 * Unregister a function that was added to be called by ftrace profiling.
1673 */
1674int unregister_ftrace_function(struct ftrace_ops *ops)
1675{
1676 int ret;
1677
1678 mutex_lock(&ftrace_sysctl_lock);
1679 ret = __unregister_ftrace_function(ops);
1680 ftrace_shutdown();
1681 mutex_unlock(&ftrace_sysctl_lock);
1682
1683 return ret;
1684}
1685
1686int
1687ftrace_enable_sysctl(struct ctl_table *table, int write,
1688 struct file *file, void __user *buffer, size_t *lenp,
1689 loff_t *ppos)
1690{
1691 int ret;
1692
1693 if (unlikely(ftrace_disabled))
1694 return -ENODEV;
1695
1696 mutex_lock(&ftrace_sysctl_lock);
1697
1698 ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
1699
1700 if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1701 goto out;
1702
1703 last_ftrace_enabled = ftrace_enabled;
1704
1705 if (ftrace_enabled) {
1706
1707 ftrace_startup_sysctl();
1708
1709 /* we are starting ftrace again */
1710 if (ftrace_list != &ftrace_list_end) {
1711 if (ftrace_list->next == &ftrace_list_end)
1712 ftrace_trace_function = ftrace_list->func;
1713 else
1714 ftrace_trace_function = ftrace_list_func;
1715 }
1716
1717 } else {
1718 /* stopping ftrace calls (just send to ftrace_stub) */
1719 ftrace_trace_function = ftrace_stub;
1720
1721 ftrace_shutdown_sysctl();
1722 }
1723
1724 out:
1725 mutex_unlock(&ftrace_sysctl_lock);
1726 return ret;
1727}
generated by cgit v1.2.2 (git 2.25.0) at 2025-12-15 14:44:03 -0500