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Merge branch 'master' of git://git2.kernel.org/pub/scm/linux/kernel/git/torvalds...
[linux-2.6/linux-2.6-openrd.git] / kernel / trace / ftrace.c
blob1e6640f80454000de4155a81a6c32a2f46816830
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/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/kprobes.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
31
32 #include <trace/events/sched.h>
33
34 #include <asm/ftrace.h>
35 #include <asm/setup.h>
36
37 #include "trace_output.h"
38 #include "trace_stat.h"
39
40 #define FTRACE_WARN_ON(cond) \
41 do { \
42 if (WARN_ON(cond)) \
43 ftrace_kill(); \
44 } while (0)
45
46 #define FTRACE_WARN_ON_ONCE(cond) \
47 do { \
48 if (WARN_ON_ONCE(cond)) \
49 ftrace_kill(); \
50 } while (0)
51
52 /* hash bits for specific function selection */
53 #define FTRACE_HASH_BITS 7
54 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
55
56 /* ftrace_enabled is a method to turn ftrace on or off */
57 int ftrace_enabled __read_mostly;
58 static int last_ftrace_enabled;
59
60 /* Quick disabling of function tracer. */
61 int function_trace_stop;
62
63 /* List for set_ftrace_pid's pids. */
64 LIST_HEAD(ftrace_pids);
65 struct ftrace_pid {
66 struct list_head list;
67 struct pid *pid;
68 };
69
70 /*
71 * ftrace_disabled is set when an anomaly is discovered.
72 * ftrace_disabled is much stronger than ftrace_enabled.
73 */
74 static int ftrace_disabled __read_mostly;
75
76 static DEFINE_MUTEX(ftrace_lock);
77
78 static struct ftrace_ops ftrace_list_end __read_mostly =
79 {
80 .func = ftrace_stub,
81 };
82
83 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
84 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
85 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
86 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
87
88 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
89 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
90 #endif
91
92 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
93 {
94 struct ftrace_ops *op = ftrace_list;
95
96 /* in case someone actually ports this to alpha! */
97 read_barrier_depends();
98
99 while (op != &ftrace_list_end) {
100 /* silly alpha */
101 read_barrier_depends();
102 op->func(ip, parent_ip);
103 op = op->next;
104 };
105 }
106
107 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
108 {
109 if (!test_tsk_trace_trace(current))
110 return;
111
112 ftrace_pid_function(ip, parent_ip);
113 }
114
115 static void set_ftrace_pid_function(ftrace_func_t func)
116 {
117 /* do not set ftrace_pid_function to itself! */
118 if (func != ftrace_pid_func)
119 ftrace_pid_function = func;
120 }
121
122 /**
123 * clear_ftrace_function - reset the ftrace function
124 *
125 * This NULLs the ftrace function and in essence stops
126 * tracing. There may be lag
127 */
128 void clear_ftrace_function(void)
129 {
130 ftrace_trace_function = ftrace_stub;
131 __ftrace_trace_function = ftrace_stub;
132 ftrace_pid_function = ftrace_stub;
133 }
134
135 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
136 /*
137 * For those archs that do not test ftrace_trace_stop in their
138 * mcount call site, we need to do it from C.
139 */
140 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
141 {
142 if (function_trace_stop)
143 return;
144
145 __ftrace_trace_function(ip, parent_ip);
146 }
147 #endif
148
149 static int __register_ftrace_function(struct ftrace_ops *ops)
150 {
151 ops->next = ftrace_list;
152 /*
153 * We are entering ops into the ftrace_list but another
154 * CPU might be walking that list. We need to make sure
155 * the ops->next pointer is valid before another CPU sees
156 * the ops pointer included into the ftrace_list.
157 */
158 smp_wmb();
159 ftrace_list = ops;
160
161 if (ftrace_enabled) {
162 ftrace_func_t func;
163
164 if (ops->next == &ftrace_list_end)
165 func = ops->func;
166 else
167 func = ftrace_list_func;
168
169 if (!list_empty(&ftrace_pids)) {
170 set_ftrace_pid_function(func);
171 func = ftrace_pid_func;
172 }
173
174 /*
175 * For one func, simply call it directly.
176 * For more than one func, call the chain.
177 */
178 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
179 ftrace_trace_function = func;
180 #else
181 __ftrace_trace_function = func;
182 ftrace_trace_function = ftrace_test_stop_func;
183 #endif
184 }
185
186 return 0;
187 }
188
189 static int __unregister_ftrace_function(struct ftrace_ops *ops)
190 {
191 struct ftrace_ops **p;
192
193 /*
194 * If we are removing the last function, then simply point
195 * to the ftrace_stub.
196 */
197 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
198 ftrace_trace_function = ftrace_stub;
199 ftrace_list = &ftrace_list_end;
200 return 0;
201 }
202
203 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
204 if (*p == ops)
205 break;
206
207 if (*p != ops)
208 return -1;
209
210 *p = (*p)->next;
211
212 if (ftrace_enabled) {
213 /* If we only have one func left, then call that directly */
214 if (ftrace_list->next == &ftrace_list_end) {
215 ftrace_func_t func = ftrace_list->func;
216
217 if (!list_empty(&ftrace_pids)) {
218 set_ftrace_pid_function(func);
219 func = ftrace_pid_func;
220 }
221 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
222 ftrace_trace_function = func;
223 #else
224 __ftrace_trace_function = func;
225 #endif
226 }
227 }
228
229 return 0;
230 }
231
232 static void ftrace_update_pid_func(void)
233 {
234 ftrace_func_t func;
235
236 if (ftrace_trace_function == ftrace_stub)
237 return;
238
239 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
240 func = ftrace_trace_function;
241 #else
242 func = __ftrace_trace_function;
243 #endif
244
245 if (!list_empty(&ftrace_pids)) {
246 set_ftrace_pid_function(func);
247 func = ftrace_pid_func;
248 } else {
249 if (func == ftrace_pid_func)
250 func = ftrace_pid_function;
251 }
252
253 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
254 ftrace_trace_function = func;
255 #else
256 __ftrace_trace_function = func;
257 #endif
258 }
259
260 #ifdef CONFIG_FUNCTION_PROFILER
261 struct ftrace_profile {
262 struct hlist_node node;
263 unsigned long ip;
264 unsigned long counter;
265 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
266 unsigned long long time;
267 #endif
268 };
269
270 struct ftrace_profile_page {
271 struct ftrace_profile_page *next;
272 unsigned long index;
273 struct ftrace_profile records[];
274 };
275
276 struct ftrace_profile_stat {
277 atomic_t disabled;
278 struct hlist_head *hash;
279 struct ftrace_profile_page *pages;
280 struct ftrace_profile_page *start;
281 struct tracer_stat stat;
282 };
283
284 #define PROFILE_RECORDS_SIZE \
285 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
286
287 #define PROFILES_PER_PAGE \
288 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
289
290 static int ftrace_profile_bits __read_mostly;
291 static int ftrace_profile_enabled __read_mostly;
292
293 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
294 static DEFINE_MUTEX(ftrace_profile_lock);
295
296 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
297
298 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
299
300 static void *
301 function_stat_next(void *v, int idx)
302 {
303 struct ftrace_profile *rec = v;
304 struct ftrace_profile_page *pg;
305
306 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
307
308 again:
309 if (idx != 0)
310 rec++;
311
312 if ((void *)rec >= (void *)&pg->records[pg->index]) {
313 pg = pg->next;
314 if (!pg)
315 return NULL;
316 rec = &pg->records[0];
317 if (!rec->counter)
318 goto again;
319 }
320
321 return rec;
322 }
323
324 static void *function_stat_start(struct tracer_stat *trace)
325 {
326 struct ftrace_profile_stat *stat =
327 container_of(trace, struct ftrace_profile_stat, stat);
328
329 if (!stat || !stat->start)
330 return NULL;
331
332 return function_stat_next(&stat->start->records[0], 0);
333 }
334
335 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
336 /* function graph compares on total time */
337 static int function_stat_cmp(void *p1, void *p2)
338 {
339 struct ftrace_profile *a = p1;
340 struct ftrace_profile *b = p2;
341
342 if (a->time < b->time)
343 return -1;
344 if (a->time > b->time)
345 return 1;
346 else
347 return 0;
348 }
349 #else
350 /* not function graph compares against hits */
351 static int function_stat_cmp(void *p1, void *p2)
352 {
353 struct ftrace_profile *a = p1;
354 struct ftrace_profile *b = p2;
355
356 if (a->counter < b->counter)
357 return -1;
358 if (a->counter > b->counter)
359 return 1;
360 else
361 return 0;
362 }
363 #endif
364
365 static int function_stat_headers(struct seq_file *m)
366 {
367 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
368 seq_printf(m, " Function "
369 "Hit Time Avg\n"
370 " -------- "
371 "--- ---- ---\n");
372 #else
373 seq_printf(m, " Function Hit\n"
374 " -------- ---\n");
375 #endif
376 return 0;
377 }
378
379 static int function_stat_show(struct seq_file *m, void *v)
380 {
381 struct ftrace_profile *rec = v;
382 char str[KSYM_SYMBOL_LEN];
383 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
384 static DEFINE_MUTEX(mutex);
385 static struct trace_seq s;
386 unsigned long long avg;
387 #endif
388
389 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
390 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
391
392 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
393 seq_printf(m, " ");
394 avg = rec->time;
395 do_div(avg, rec->counter);
396
397 mutex_lock(&mutex);
398 trace_seq_init(&s);
399 trace_print_graph_duration(rec->time, &s);
400 trace_seq_puts(&s, " ");
401 trace_print_graph_duration(avg, &s);
402 trace_print_seq(m, &s);
403 mutex_unlock(&mutex);
404 #endif
405 seq_putc(m, '\n');
406
407 return 0;
408 }
409
410 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
411 {
412 struct ftrace_profile_page *pg;
413
414 pg = stat->pages = stat->start;
415
416 while (pg) {
417 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
418 pg->index = 0;
419 pg = pg->next;
420 }
421
422 memset(stat->hash, 0,
423 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
424 }
425
426 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
427 {
428 struct ftrace_profile_page *pg;
429 int functions;
430 int pages;
431 int i;
432
433 /* If we already allocated, do nothing */
434 if (stat->pages)
435 return 0;
436
437 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
438 if (!stat->pages)
439 return -ENOMEM;
440
441 #ifdef CONFIG_DYNAMIC_FTRACE
442 functions = ftrace_update_tot_cnt;
443 #else
444 /*
445 * We do not know the number of functions that exist because
446 * dynamic tracing is what counts them. With past experience
447 * we have around 20K functions. That should be more than enough.
448 * It is highly unlikely we will execute every function in
449 * the kernel.
450 */
451 functions = 20000;
452 #endif
453
454 pg = stat->start = stat->pages;
455
456 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
457
458 for (i = 0; i < pages; i++) {
459 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
460 if (!pg->next)
461 goto out_free;
462 pg = pg->next;
463 }
464
465 return 0;
466
467 out_free:
468 pg = stat->start;
469 while (pg) {
470 unsigned long tmp = (unsigned long)pg;
471
472 pg = pg->next;
473 free_page(tmp);
474 }
475
476 free_page((unsigned long)stat->pages);
477 stat->pages = NULL;
478 stat->start = NULL;
479
480 return -ENOMEM;
481 }
482
483 static int ftrace_profile_init_cpu(int cpu)
484 {
485 struct ftrace_profile_stat *stat;
486 int size;
487
488 stat = &per_cpu(ftrace_profile_stats, cpu);
489
490 if (stat->hash) {
491 /* If the profile is already created, simply reset it */
492 ftrace_profile_reset(stat);
493 return 0;
494 }
495
496 /*
497 * We are profiling all functions, but usually only a few thousand
498 * functions are hit. We'll make a hash of 1024 items.
499 */
500 size = FTRACE_PROFILE_HASH_SIZE;
501
502 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
503
504 if (!stat->hash)
505 return -ENOMEM;
506
507 if (!ftrace_profile_bits) {
508 size--;
509
510 for (; size; size >>= 1)
511 ftrace_profile_bits++;
512 }
513
514 /* Preallocate the function profiling pages */
515 if (ftrace_profile_pages_init(stat) < 0) {
516 kfree(stat->hash);
517 stat->hash = NULL;
518 return -ENOMEM;
519 }
520
521 return 0;
522 }
523
524 static int ftrace_profile_init(void)
525 {
526 int cpu;
527 int ret = 0;
528
529 for_each_online_cpu(cpu) {
530 ret = ftrace_profile_init_cpu(cpu);
531 if (ret)
532 break;
533 }
534
535 return ret;
536 }
537
538 /* interrupts must be disabled */
539 static struct ftrace_profile *
540 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
541 {
542 struct ftrace_profile *rec;
543 struct hlist_head *hhd;
544 struct hlist_node *n;
545 unsigned long key;
546
547 key = hash_long(ip, ftrace_profile_bits);
548 hhd = &stat->hash[key];
549
550 if (hlist_empty(hhd))
551 return NULL;
552
553 hlist_for_each_entry_rcu(rec, n, hhd, node) {
554 if (rec->ip == ip)
555 return rec;
556 }
557
558 return NULL;
559 }
560
561 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
562 struct ftrace_profile *rec)
563 {
564 unsigned long key;
565
566 key = hash_long(rec->ip, ftrace_profile_bits);
567 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
568 }
569
570 /*
571 * The memory is already allocated, this simply finds a new record to use.
572 */
573 static struct ftrace_profile *
574 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
575 {
576 struct ftrace_profile *rec = NULL;
577
578 /* prevent recursion (from NMIs) */
579 if (atomic_inc_return(&stat->disabled) != 1)
580 goto out;
581
582 /*
583 * Try to find the function again since an NMI
584 * could have added it
585 */
586 rec = ftrace_find_profiled_func(stat, ip);
587 if (rec)
588 goto out;
589
590 if (stat->pages->index == PROFILES_PER_PAGE) {
591 if (!stat->pages->next)
592 goto out;
593 stat->pages = stat->pages->next;
594 }
595
596 rec = &stat->pages->records[stat->pages->index++];
597 rec->ip = ip;
598 ftrace_add_profile(stat, rec);
599
600 out:
601 atomic_dec(&stat->disabled);
602
603 return rec;
604 }
605
606 static void
607 function_profile_call(unsigned long ip, unsigned long parent_ip)
608 {
609 struct ftrace_profile_stat *stat;
610 struct ftrace_profile *rec;
611 unsigned long flags;
612
613 if (!ftrace_profile_enabled)
614 return;
615
616 local_irq_save(flags);
617
618 stat = &__get_cpu_var(ftrace_profile_stats);
619 if (!stat->hash || !ftrace_profile_enabled)
620 goto out;
621
622 rec = ftrace_find_profiled_func(stat, ip);
623 if (!rec) {
624 rec = ftrace_profile_alloc(stat, ip);
625 if (!rec)
626 goto out;
627 }
628
629 rec->counter++;
630 out:
631 local_irq_restore(flags);
632 }
633
634 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
635 static int profile_graph_entry(struct ftrace_graph_ent *trace)
636 {
637 function_profile_call(trace->func, 0);
638 return 1;
639 }
640
641 static void profile_graph_return(struct ftrace_graph_ret *trace)
642 {
643 struct ftrace_profile_stat *stat;
644 unsigned long long calltime;
645 struct ftrace_profile *rec;
646 unsigned long flags;
647
648 local_irq_save(flags);
649 stat = &__get_cpu_var(ftrace_profile_stats);
650 if (!stat->hash || !ftrace_profile_enabled)
651 goto out;
652
653 calltime = trace->rettime - trace->calltime;
654
655 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
656 int index;
657
658 index = trace->depth;
659
660 /* Append this call time to the parent time to subtract */
661 if (index)
662 current->ret_stack[index - 1].subtime += calltime;
663
664 if (current->ret_stack[index].subtime < calltime)
665 calltime -= current->ret_stack[index].subtime;
666 else
667 calltime = 0;
668 }
669
670 rec = ftrace_find_profiled_func(stat, trace->func);
671 if (rec)
672 rec->time += calltime;
673
674 out:
675 local_irq_restore(flags);
676 }
677
678 static int register_ftrace_profiler(void)
679 {
680 return register_ftrace_graph(&profile_graph_return,
681 &profile_graph_entry);
682 }
683
684 static void unregister_ftrace_profiler(void)
685 {
686 unregister_ftrace_graph();
687 }
688 #else
689 static struct ftrace_ops ftrace_profile_ops __read_mostly =
690 {
691 .func = function_profile_call,
692 };
693
694 static int register_ftrace_profiler(void)
695 {
696 return register_ftrace_function(&ftrace_profile_ops);
697 }
698
699 static void unregister_ftrace_profiler(void)
700 {
701 unregister_ftrace_function(&ftrace_profile_ops);
702 }
703 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
704
705 static ssize_t
706 ftrace_profile_write(struct file *filp, const char __user *ubuf,
707 size_t cnt, loff_t *ppos)
708 {
709 unsigned long val;
710 char buf[64]; /* big enough to hold a number */
711 int ret;
712
713 if (cnt >= sizeof(buf))
714 return -EINVAL;
715
716 if (copy_from_user(&buf, ubuf, cnt))
717 return -EFAULT;
718
719 buf[cnt] = 0;
720
721 ret = strict_strtoul(buf, 10, &val);
722 if (ret < 0)
723 return ret;
724
725 val = !!val;
726
727 mutex_lock(&ftrace_profile_lock);
728 if (ftrace_profile_enabled ^ val) {
729 if (val) {
730 ret = ftrace_profile_init();
731 if (ret < 0) {
732 cnt = ret;
733 goto out;
734 }
735
736 ret = register_ftrace_profiler();
737 if (ret < 0) {
738 cnt = ret;
739 goto out;
740 }
741 ftrace_profile_enabled = 1;
742 } else {
743 ftrace_profile_enabled = 0;
744 /*
745 * unregister_ftrace_profiler calls stop_machine
746 * so this acts like an synchronize_sched.
747 */
748 unregister_ftrace_profiler();
749 }
750 }
751 out:
752 mutex_unlock(&ftrace_profile_lock);
753
754 *ppos += cnt;
755
756 return cnt;
757 }
758
759 static ssize_t
760 ftrace_profile_read(struct file *filp, char __user *ubuf,
761 size_t cnt, loff_t *ppos)
762 {
763 char buf[64]; /* big enough to hold a number */
764 int r;
765
766 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
767 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
768 }
769
770 static const struct file_operations ftrace_profile_fops = {
771 .open = tracing_open_generic,
772 .read = ftrace_profile_read,
773 .write = ftrace_profile_write,
774 };
775
776 /* used to initialize the real stat files */
777 static struct tracer_stat function_stats __initdata = {
778 .name = "functions",
779 .stat_start = function_stat_start,
780 .stat_next = function_stat_next,
781 .stat_cmp = function_stat_cmp,
782 .stat_headers = function_stat_headers,
783 .stat_show = function_stat_show
784 };
785
786 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
787 {
788 struct ftrace_profile_stat *stat;
789 struct dentry *entry;
790 char *name;
791 int ret;
792 int cpu;
793
794 for_each_possible_cpu(cpu) {
795 stat = &per_cpu(ftrace_profile_stats, cpu);
796
797 /* allocate enough for function name + cpu number */
798 name = kmalloc(32, GFP_KERNEL);
799 if (!name) {
800 /*
801 * The files created are permanent, if something happens
802 * we still do not free memory.
803 */
804 WARN(1,
805 "Could not allocate stat file for cpu %d\n",
806 cpu);
807 return;
808 }
809 stat->stat = function_stats;
810 snprintf(name, 32, "function%d", cpu);
811 stat->stat.name = name;
812 ret = register_stat_tracer(&stat->stat);
813 if (ret) {
814 WARN(1,
815 "Could not register function stat for cpu %d\n",
816 cpu);
817 kfree(name);
818 return;
819 }
820 }
821
822 entry = debugfs_create_file("function_profile_enabled", 0644,
823 d_tracer, NULL, &ftrace_profile_fops);
824 if (!entry)
825 pr_warning("Could not create debugfs "
826 "'function_profile_enabled' entry\n");
827 }
828
829 #else /* CONFIG_FUNCTION_PROFILER */
830 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
831 {
832 }
833 #endif /* CONFIG_FUNCTION_PROFILER */
834
835 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
836
837 #ifdef CONFIG_DYNAMIC_FTRACE
838
839 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
840 # error Dynamic ftrace depends on MCOUNT_RECORD
841 #endif
842
843 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
844
845 struct ftrace_func_probe {
846 struct hlist_node node;
847 struct ftrace_probe_ops *ops;
848 unsigned long flags;
849 unsigned long ip;
850 void *data;
851 struct rcu_head rcu;
852 };
853
854 enum {
855 FTRACE_ENABLE_CALLS = (1 << 0),
856 FTRACE_DISABLE_CALLS = (1 << 1),
857 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
858 FTRACE_ENABLE_MCOUNT = (1 << 3),
859 FTRACE_DISABLE_MCOUNT = (1 << 4),
860 FTRACE_START_FUNC_RET = (1 << 5),
861 FTRACE_STOP_FUNC_RET = (1 << 6),
862 };
863
864 static int ftrace_filtered;
865
866 static struct dyn_ftrace *ftrace_new_addrs;
867
868 static DEFINE_MUTEX(ftrace_regex_lock);
869
870 struct ftrace_page {
871 struct ftrace_page *next;
872 int index;
873 struct dyn_ftrace records[];
874 };
875
876 #define ENTRIES_PER_PAGE \
877 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
878
879 /* estimate from running different kernels */
880 #define NR_TO_INIT 10000
881
882 static struct ftrace_page *ftrace_pages_start;
883 static struct ftrace_page *ftrace_pages;
884
885 static struct dyn_ftrace *ftrace_free_records;
886
887 /*
888 * This is a double for. Do not use 'break' to break out of the loop,
889 * you must use a goto.
890 */
891 #define do_for_each_ftrace_rec(pg, rec) \
892 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
893 int _____i; \
894 for (_____i = 0; _____i < pg->index; _____i++) { \
895 rec = &pg->records[_____i];
896
897 #define while_for_each_ftrace_rec() \
898 } \
899 }
900
901 #ifdef CONFIG_KPROBES
902
903 static int frozen_record_count;
904
905 static inline void freeze_record(struct dyn_ftrace *rec)
906 {
907 if (!(rec->flags & FTRACE_FL_FROZEN)) {
908 rec->flags |= FTRACE_FL_FROZEN;
909 frozen_record_count++;
910 }
911 }
912
913 static inline void unfreeze_record(struct dyn_ftrace *rec)
914 {
915 if (rec->flags & FTRACE_FL_FROZEN) {
916 rec->flags &= ~FTRACE_FL_FROZEN;
917 frozen_record_count--;
918 }
919 }
920
921 static inline int record_frozen(struct dyn_ftrace *rec)
922 {
923 return rec->flags & FTRACE_FL_FROZEN;
924 }
925 #else
926 # define freeze_record(rec) ({ 0; })
927 # define unfreeze_record(rec) ({ 0; })
928 # define record_frozen(rec) ({ 0; })
929 #endif /* CONFIG_KPROBES */
930
931 static void ftrace_free_rec(struct dyn_ftrace *rec)
932 {
933 rec->freelist = ftrace_free_records;
934 ftrace_free_records = rec;
935 rec->flags |= FTRACE_FL_FREE;
936 }
937
938 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
939 {
940 struct dyn_ftrace *rec;
941
942 /* First check for freed records */
943 if (ftrace_free_records) {
944 rec = ftrace_free_records;
945
946 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
947 FTRACE_WARN_ON_ONCE(1);
948 ftrace_free_records = NULL;
949 return NULL;
950 }
951
952 ftrace_free_records = rec->freelist;
953 memset(rec, 0, sizeof(*rec));
954 return rec;
955 }
956
957 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
958 if (!ftrace_pages->next) {
959 /* allocate another page */
960 ftrace_pages->next =
961 (void *)get_zeroed_page(GFP_KERNEL);
962 if (!ftrace_pages->next)
963 return NULL;
964 }
965 ftrace_pages = ftrace_pages->next;
966 }
967
968 return &ftrace_pages->records[ftrace_pages->index++];
969 }
970
971 static struct dyn_ftrace *
972 ftrace_record_ip(unsigned long ip)
973 {
974 struct dyn_ftrace *rec;
975
976 if (ftrace_disabled)
977 return NULL;
978
979 rec = ftrace_alloc_dyn_node(ip);
980 if (!rec)
981 return NULL;
982
983 rec->ip = ip;
984 rec->newlist = ftrace_new_addrs;
985 ftrace_new_addrs = rec;
986
987 return rec;
988 }
989
990 static void print_ip_ins(const char *fmt, unsigned char *p)
991 {
992 int i;
993
994 printk(KERN_CONT "%s", fmt);
995
996 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
997 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
998 }
999
1000 static void ftrace_bug(int failed, unsigned long ip)
1001 {
1002 switch (failed) {
1003 case -EFAULT:
1004 FTRACE_WARN_ON_ONCE(1);
1005 pr_info("ftrace faulted on modifying ");
1006 print_ip_sym(ip);
1007 break;
1008 case -EINVAL:
1009 FTRACE_WARN_ON_ONCE(1);
1010 pr_info("ftrace failed to modify ");
1011 print_ip_sym(ip);
1012 print_ip_ins(" actual: ", (unsigned char *)ip);
1013 printk(KERN_CONT "\n");
1014 break;
1015 case -EPERM:
1016 FTRACE_WARN_ON_ONCE(1);
1017 pr_info("ftrace faulted on writing ");
1018 print_ip_sym(ip);
1019 break;
1020 default:
1021 FTRACE_WARN_ON_ONCE(1);
1022 pr_info("ftrace faulted on unknown error ");
1023 print_ip_sym(ip);
1024 }
1025 }
1026
1027
1028 static int
1029 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1030 {
1031 unsigned long ftrace_addr;
1032 unsigned long flag = 0UL;
1033
1034 ftrace_addr = (unsigned long)FTRACE_ADDR;
1035
1036 /*
1037 * If this record is not to be traced or we want to disable it,
1038 * then disable it.
1039 *
1040 * If we want to enable it and filtering is off, then enable it.
1041 *
1042 * If we want to enable it and filtering is on, enable it only if
1043 * it's filtered
1044 */
1045 if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1046 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1047 flag = FTRACE_FL_ENABLED;
1048 }
1049
1050 /* If the state of this record hasn't changed, then do nothing */
1051 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1052 return 0;
1053
1054 if (flag) {
1055 rec->flags |= FTRACE_FL_ENABLED;
1056 return ftrace_make_call(rec, ftrace_addr);
1057 }
1058
1059 rec->flags &= ~FTRACE_FL_ENABLED;
1060 return ftrace_make_nop(NULL, rec, ftrace_addr);
1061 }
1062
1063 static void ftrace_replace_code(int enable)
1064 {
1065 struct dyn_ftrace *rec;
1066 struct ftrace_page *pg;
1067 int failed;
1068
1069 do_for_each_ftrace_rec(pg, rec) {
1070 /*
1071 * Skip over free records, records that have
1072 * failed and not converted.
1073 */
1074 if (rec->flags & FTRACE_FL_FREE ||
1075 rec->flags & FTRACE_FL_FAILED ||
1076 !(rec->flags & FTRACE_FL_CONVERTED))
1077 continue;
1078
1079 /* ignore updates to this record's mcount site */
1080 if (get_kprobe((void *)rec->ip)) {
1081 freeze_record(rec);
1082 continue;
1083 } else {
1084 unfreeze_record(rec);
1085 }
1086
1087 failed = __ftrace_replace_code(rec, enable);
1088 if (failed) {
1089 rec->flags |= FTRACE_FL_FAILED;
1090 ftrace_bug(failed, rec->ip);
1091 /* Stop processing */
1092 return;
1093 }
1094 } while_for_each_ftrace_rec();
1095 }
1096
1097 static int
1098 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1099 {
1100 unsigned long ip;
1101 int ret;
1102
1103 ip = rec->ip;
1104
1105 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1106 if (ret) {
1107 ftrace_bug(ret, ip);
1108 rec->flags |= FTRACE_FL_FAILED;
1109 return 0;
1110 }
1111 return 1;
1112 }
1113
1114 /*
1115 * archs can override this function if they must do something
1116 * before the modifying code is performed.
1117 */
1118 int __weak ftrace_arch_code_modify_prepare(void)
1119 {
1120 return 0;
1121 }
1122
1123 /*
1124 * archs can override this function if they must do something
1125 * after the modifying code is performed.
1126 */
1127 int __weak ftrace_arch_code_modify_post_process(void)
1128 {
1129 return 0;
1130 }
1131
1132 static int __ftrace_modify_code(void *data)
1133 {
1134 int *command = data;
1135
1136 if (*command & FTRACE_ENABLE_CALLS)
1137 ftrace_replace_code(1);
1138 else if (*command & FTRACE_DISABLE_CALLS)
1139 ftrace_replace_code(0);
1140
1141 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1142 ftrace_update_ftrace_func(ftrace_trace_function);
1143
1144 if (*command & FTRACE_START_FUNC_RET)
1145 ftrace_enable_ftrace_graph_caller();
1146 else if (*command & FTRACE_STOP_FUNC_RET)
1147 ftrace_disable_ftrace_graph_caller();
1148
1149 return 0;
1150 }
1151
1152 static void ftrace_run_update_code(int command)
1153 {
1154 int ret;
1155
1156 ret = ftrace_arch_code_modify_prepare();
1157 FTRACE_WARN_ON(ret);
1158 if (ret)
1159 return;
1160
1161 stop_machine(__ftrace_modify_code, &command, NULL);
1162
1163 ret = ftrace_arch_code_modify_post_process();
1164 FTRACE_WARN_ON(ret);
1165 }
1166
1167 static ftrace_func_t saved_ftrace_func;
1168 static int ftrace_start_up;
1169
1170 static void ftrace_startup_enable(int command)
1171 {
1172 if (saved_ftrace_func != ftrace_trace_function) {
1173 saved_ftrace_func = ftrace_trace_function;
1174 command |= FTRACE_UPDATE_TRACE_FUNC;
1175 }
1176
1177 if (!command || !ftrace_enabled)
1178 return;
1179
1180 ftrace_run_update_code(command);
1181 }
1182
1183 static void ftrace_startup(int command)
1184 {
1185 if (unlikely(ftrace_disabled))
1186 return;
1187
1188 ftrace_start_up++;
1189 command |= FTRACE_ENABLE_CALLS;
1190
1191 ftrace_startup_enable(command);
1192 }
1193
1194 static void ftrace_shutdown(int command)
1195 {
1196 if (unlikely(ftrace_disabled))
1197 return;
1198
1199 ftrace_start_up--;
1200 /*
1201 * Just warn in case of unbalance, no need to kill ftrace, it's not
1202 * critical but the ftrace_call callers may be never nopped again after
1203 * further ftrace uses.
1204 */
1205 WARN_ON_ONCE(ftrace_start_up < 0);
1206
1207 if (!ftrace_start_up)
1208 command |= FTRACE_DISABLE_CALLS;
1209
1210 if (saved_ftrace_func != ftrace_trace_function) {
1211 saved_ftrace_func = ftrace_trace_function;
1212 command |= FTRACE_UPDATE_TRACE_FUNC;
1213 }
1214
1215 if (!command || !ftrace_enabled)
1216 return;
1217
1218 ftrace_run_update_code(command);
1219 }
1220
1221 static void ftrace_startup_sysctl(void)
1222 {
1223 int command = FTRACE_ENABLE_MCOUNT;
1224
1225 if (unlikely(ftrace_disabled))
1226 return;
1227
1228 /* Force update next time */
1229 saved_ftrace_func = NULL;
1230 /* ftrace_start_up is true if we want ftrace running */
1231 if (ftrace_start_up)
1232 command |= FTRACE_ENABLE_CALLS;
1233
1234 ftrace_run_update_code(command);
1235 }
1236
1237 static void ftrace_shutdown_sysctl(void)
1238 {
1239 int command = FTRACE_DISABLE_MCOUNT;
1240
1241 if (unlikely(ftrace_disabled))
1242 return;
1243
1244 /* ftrace_start_up is true if ftrace is running */
1245 if (ftrace_start_up)
1246 command |= FTRACE_DISABLE_CALLS;
1247
1248 ftrace_run_update_code(command);
1249 }
1250
1251 static cycle_t ftrace_update_time;
1252 static unsigned long ftrace_update_cnt;
1253 unsigned long ftrace_update_tot_cnt;
1254
1255 static int ftrace_update_code(struct module *mod)
1256 {
1257 struct dyn_ftrace *p;
1258 cycle_t start, stop;
1259
1260 start = ftrace_now(raw_smp_processor_id());
1261 ftrace_update_cnt = 0;
1262
1263 while (ftrace_new_addrs) {
1264
1265 /* If something went wrong, bail without enabling anything */
1266 if (unlikely(ftrace_disabled))
1267 return -1;
1268
1269 p = ftrace_new_addrs;
1270 ftrace_new_addrs = p->newlist;
1271 p->flags = 0L;
1272
1273 /*
1274 * Do the initial record convertion from mcount jump
1275 * to the NOP instructions.
1276 */
1277 if (!ftrace_code_disable(mod, p)) {
1278 ftrace_free_rec(p);
1279 continue;
1280 }
1281
1282 p->flags |= FTRACE_FL_CONVERTED;
1283 ftrace_update_cnt++;
1284
1285 /*
1286 * If the tracing is enabled, go ahead and enable the record.
1287 *
1288 * The reason not to enable the record immediatelly is the
1289 * inherent check of ftrace_make_nop/ftrace_make_call for
1290 * correct previous instructions. Making first the NOP
1291 * conversion puts the module to the correct state, thus
1292 * passing the ftrace_make_call check.
1293 */
1294 if (ftrace_start_up) {
1295 int failed = __ftrace_replace_code(p, 1);
1296 if (failed) {
1297 ftrace_bug(failed, p->ip);
1298 ftrace_free_rec(p);
1299 }
1300 }
1301 }
1302
1303 stop = ftrace_now(raw_smp_processor_id());
1304 ftrace_update_time = stop - start;
1305 ftrace_update_tot_cnt += ftrace_update_cnt;
1306
1307 return 0;
1308 }
1309
1310 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1311 {
1312 struct ftrace_page *pg;
1313 int cnt;
1314 int i;
1315
1316 /* allocate a few pages */
1317 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1318 if (!ftrace_pages_start)
1319 return -1;
1320
1321 /*
1322 * Allocate a few more pages.
1323 *
1324 * TODO: have some parser search vmlinux before
1325 * final linking to find all calls to ftrace.
1326 * Then we can:
1327 * a) know how many pages to allocate.
1328 * and/or
1329 * b) set up the table then.
1330 *
1331 * The dynamic code is still necessary for
1332 * modules.
1333 */
1334
1335 pg = ftrace_pages = ftrace_pages_start;
1336
1337 cnt = num_to_init / ENTRIES_PER_PAGE;
1338 pr_info("ftrace: allocating %ld entries in %d pages\n",
1339 num_to_init, cnt + 1);
1340
1341 for (i = 0; i < cnt; i++) {
1342 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1343
1344 /* If we fail, we'll try later anyway */
1345 if (!pg->next)
1346 break;
1347
1348 pg = pg->next;
1349 }
1350
1351 return 0;
1352 }
1353
1354 enum {
1355 FTRACE_ITER_FILTER = (1 << 0),
1356 FTRACE_ITER_NOTRACE = (1 << 1),
1357 FTRACE_ITER_FAILURES = (1 << 2),
1358 FTRACE_ITER_PRINTALL = (1 << 3),
1359 FTRACE_ITER_HASH = (1 << 4),
1360 };
1361
1362 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1363
1364 struct ftrace_iterator {
1365 struct ftrace_page *pg;
1366 int hidx;
1367 int idx;
1368 unsigned flags;
1369 struct trace_parser parser;
1370 };
1371
1372 static void *
1373 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1374 {
1375 struct ftrace_iterator *iter = m->private;
1376 struct hlist_node *hnd = v;
1377 struct hlist_head *hhd;
1378
1379 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1380
1381 (*pos)++;
1382
1383 retry:
1384 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1385 return NULL;
1386
1387 hhd = &ftrace_func_hash[iter->hidx];
1388
1389 if (hlist_empty(hhd)) {
1390 iter->hidx++;
1391 hnd = NULL;
1392 goto retry;
1393 }
1394
1395 if (!hnd)
1396 hnd = hhd->first;
1397 else {
1398 hnd = hnd->next;
1399 if (!hnd) {
1400 iter->hidx++;
1401 goto retry;
1402 }
1403 }
1404
1405 return hnd;
1406 }
1407
1408 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1409 {
1410 struct ftrace_iterator *iter = m->private;
1411 void *p = NULL;
1412 loff_t l;
1413
1414 if (!(iter->flags & FTRACE_ITER_HASH))
1415 *pos = 0;
1416
1417 iter->flags |= FTRACE_ITER_HASH;
1418
1419 iter->hidx = 0;
1420 for (l = 0; l <= *pos; ) {
1421 p = t_hash_next(m, p, &l);
1422 if (!p)
1423 break;
1424 }
1425 return p;
1426 }
1427
1428 static int t_hash_show(struct seq_file *m, void *v)
1429 {
1430 struct ftrace_func_probe *rec;
1431 struct hlist_node *hnd = v;
1432
1433 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1434
1435 if (rec->ops->print)
1436 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1437
1438 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1439
1440 if (rec->data)
1441 seq_printf(m, ":%p", rec->data);
1442 seq_putc(m, '\n');
1443
1444 return 0;
1445 }
1446
1447 static void *
1448 t_next(struct seq_file *m, void *v, loff_t *pos)
1449 {
1450 struct ftrace_iterator *iter = m->private;
1451 struct dyn_ftrace *rec = NULL;
1452
1453 if (iter->flags & FTRACE_ITER_HASH)
1454 return t_hash_next(m, v, pos);
1455
1456 (*pos)++;
1457
1458 if (iter->flags & FTRACE_ITER_PRINTALL)
1459 return NULL;
1460
1461 retry:
1462 if (iter->idx >= iter->pg->index) {
1463 if (iter->pg->next) {
1464 iter->pg = iter->pg->next;
1465 iter->idx = 0;
1466 goto retry;
1467 }
1468 } else {
1469 rec = &iter->pg->records[iter->idx++];
1470 if ((rec->flags & FTRACE_FL_FREE) ||
1471
1472 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1473 (rec->flags & FTRACE_FL_FAILED)) ||
1474
1475 ((iter->flags & FTRACE_ITER_FAILURES) &&
1476 !(rec->flags & FTRACE_FL_FAILED)) ||
1477
1478 ((iter->flags & FTRACE_ITER_FILTER) &&
1479 !(rec->flags & FTRACE_FL_FILTER)) ||
1480
1481 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1482 !(rec->flags & FTRACE_FL_NOTRACE))) {
1483 rec = NULL;
1484 goto retry;
1485 }
1486 }
1487
1488 return rec;
1489 }
1490
1491 static void *t_start(struct seq_file *m, loff_t *pos)
1492 {
1493 struct ftrace_iterator *iter = m->private;
1494 void *p = NULL;
1495 loff_t l;
1496
1497 mutex_lock(&ftrace_lock);
1498 /*
1499 * For set_ftrace_filter reading, if we have the filter
1500 * off, we can short cut and just print out that all
1501 * functions are enabled.
1502 */
1503 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1504 if (*pos > 0)
1505 return t_hash_start(m, pos);
1506 iter->flags |= FTRACE_ITER_PRINTALL;
1507 return iter;
1508 }
1509
1510 if (iter->flags & FTRACE_ITER_HASH)
1511 return t_hash_start(m, pos);
1512
1513 iter->pg = ftrace_pages_start;
1514 iter->idx = 0;
1515 for (l = 0; l <= *pos; ) {
1516 p = t_next(m, p, &l);
1517 if (!p)
1518 break;
1519 }
1520
1521 if (!p && iter->flags & FTRACE_ITER_FILTER)
1522 return t_hash_start(m, pos);
1523
1524 return p;
1525 }
1526
1527 static void t_stop(struct seq_file *m, void *p)
1528 {
1529 mutex_unlock(&ftrace_lock);
1530 }
1531
1532 static int t_show(struct seq_file *m, void *v)
1533 {
1534 struct ftrace_iterator *iter = m->private;
1535 struct dyn_ftrace *rec = v;
1536
1537 if (iter->flags & FTRACE_ITER_HASH)
1538 return t_hash_show(m, v);
1539
1540 if (iter->flags & FTRACE_ITER_PRINTALL) {
1541 seq_printf(m, "#### all functions enabled ####\n");
1542 return 0;
1543 }
1544
1545 if (!rec)
1546 return 0;
1547
1548 seq_printf(m, "%ps\n", (void *)rec->ip);
1549
1550 return 0;
1551 }
1552
1553 static const struct seq_operations show_ftrace_seq_ops = {
1554 .start = t_start,
1555 .next = t_next,
1556 .stop = t_stop,
1557 .show = t_show,
1558 };
1559
1560 static int
1561 ftrace_avail_open(struct inode *inode, struct file *file)
1562 {
1563 struct ftrace_iterator *iter;
1564 int ret;
1565
1566 if (unlikely(ftrace_disabled))
1567 return -ENODEV;
1568
1569 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1570 if (!iter)
1571 return -ENOMEM;
1572
1573 iter->pg = ftrace_pages_start;
1574
1575 ret = seq_open(file, &show_ftrace_seq_ops);
1576 if (!ret) {
1577 struct seq_file *m = file->private_data;
1578
1579 m->private = iter;
1580 } else {
1581 kfree(iter);
1582 }
1583
1584 return ret;
1585 }
1586
1587 static int
1588 ftrace_failures_open(struct inode *inode, struct file *file)
1589 {
1590 int ret;
1591 struct seq_file *m;
1592 struct ftrace_iterator *iter;
1593
1594 ret = ftrace_avail_open(inode, file);
1595 if (!ret) {
1596 m = (struct seq_file *)file->private_data;
1597 iter = (struct ftrace_iterator *)m->private;
1598 iter->flags = FTRACE_ITER_FAILURES;
1599 }
1600
1601 return ret;
1602 }
1603
1604
1605 static void ftrace_filter_reset(int enable)
1606 {
1607 struct ftrace_page *pg;
1608 struct dyn_ftrace *rec;
1609 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1610
1611 mutex_lock(&ftrace_lock);
1612 if (enable)
1613 ftrace_filtered = 0;
1614 do_for_each_ftrace_rec(pg, rec) {
1615 if (rec->flags & FTRACE_FL_FAILED)
1616 continue;
1617 rec->flags &= ~type;
1618 } while_for_each_ftrace_rec();
1619 mutex_unlock(&ftrace_lock);
1620 }
1621
1622 static int
1623 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1624 {
1625 struct ftrace_iterator *iter;
1626 int ret = 0;
1627
1628 if (unlikely(ftrace_disabled))
1629 return -ENODEV;
1630
1631 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1632 if (!iter)
1633 return -ENOMEM;
1634
1635 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1636 kfree(iter);
1637 return -ENOMEM;
1638 }
1639
1640 mutex_lock(&ftrace_regex_lock);
1641 if ((file->f_mode & FMODE_WRITE) &&
1642 (file->f_flags & O_TRUNC))
1643 ftrace_filter_reset(enable);
1644
1645 if (file->f_mode & FMODE_READ) {
1646 iter->pg = ftrace_pages_start;
1647 iter->flags = enable ? FTRACE_ITER_FILTER :
1648 FTRACE_ITER_NOTRACE;
1649
1650 ret = seq_open(file, &show_ftrace_seq_ops);
1651 if (!ret) {
1652 struct seq_file *m = file->private_data;
1653 m->private = iter;
1654 } else {
1655 trace_parser_put(&iter->parser);
1656 kfree(iter);
1657 }
1658 } else
1659 file->private_data = iter;
1660 mutex_unlock(&ftrace_regex_lock);
1661
1662 return ret;
1663 }
1664
1665 static int
1666 ftrace_filter_open(struct inode *inode, struct file *file)
1667 {
1668 return ftrace_regex_open(inode, file, 1);
1669 }
1670
1671 static int
1672 ftrace_notrace_open(struct inode *inode, struct file *file)
1673 {
1674 return ftrace_regex_open(inode, file, 0);
1675 }
1676
1677 static loff_t
1678 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1679 {
1680 loff_t ret;
1681
1682 if (file->f_mode & FMODE_READ)
1683 ret = seq_lseek(file, offset, origin);
1684 else
1685 file->f_pos = ret = 1;
1686
1687 return ret;
1688 }
1689
1690 static int ftrace_match(char *str, char *regex, int len, int type)
1691 {
1692 int matched = 0;
1693 int slen;
1694
1695 switch (type) {
1696 case MATCH_FULL:
1697 if (strcmp(str, regex) == 0)
1698 matched = 1;
1699 break;
1700 case MATCH_FRONT_ONLY:
1701 if (strncmp(str, regex, len) == 0)
1702 matched = 1;
1703 break;
1704 case MATCH_MIDDLE_ONLY:
1705 if (strstr(str, regex))
1706 matched = 1;
1707 break;
1708 case MATCH_END_ONLY:
1709 slen = strlen(str);
1710 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1711 matched = 1;
1712 break;
1713 }
1714
1715 return matched;
1716 }
1717
1718 static int
1719 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1720 {
1721 char str[KSYM_SYMBOL_LEN];
1722
1723 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1724 return ftrace_match(str, regex, len, type);
1725 }
1726
1727 static int ftrace_match_records(char *buff, int len, int enable)
1728 {
1729 unsigned int search_len;
1730 struct ftrace_page *pg;
1731 struct dyn_ftrace *rec;
1732 unsigned long flag;
1733 char *search;
1734 int type;
1735 int not;
1736 int found = 0;
1737
1738 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1739 type = filter_parse_regex(buff, len, &search, &not);
1740
1741 search_len = strlen(search);
1742
1743 mutex_lock(&ftrace_lock);
1744 do_for_each_ftrace_rec(pg, rec) {
1745
1746 if (rec->flags & FTRACE_FL_FAILED)
1747 continue;
1748
1749 if (ftrace_match_record(rec, search, search_len, type)) {
1750 if (not)
1751 rec->flags &= ~flag;
1752 else
1753 rec->flags |= flag;
1754 found = 1;
1755 }
1756 /*
1757 * Only enable filtering if we have a function that
1758 * is filtered on.
1759 */
1760 if (enable && (rec->flags & FTRACE_FL_FILTER))
1761 ftrace_filtered = 1;
1762 } while_for_each_ftrace_rec();
1763 mutex_unlock(&ftrace_lock);
1764
1765 return found;
1766 }
1767
1768 static int
1769 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1770 char *regex, int len, int type)
1771 {
1772 char str[KSYM_SYMBOL_LEN];
1773 char *modname;
1774
1775 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1776
1777 if (!modname || strcmp(modname, mod))
1778 return 0;
1779
1780 /* blank search means to match all funcs in the mod */
1781 if (len)
1782 return ftrace_match(str, regex, len, type);
1783 else
1784 return 1;
1785 }
1786
1787 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1788 {
1789 unsigned search_len = 0;
1790 struct ftrace_page *pg;
1791 struct dyn_ftrace *rec;
1792 int type = MATCH_FULL;
1793 char *search = buff;
1794 unsigned long flag;
1795 int not = 0;
1796 int found = 0;
1797
1798 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1799
1800 /* blank or '*' mean the same */
1801 if (strcmp(buff, "*") == 0)
1802 buff[0] = 0;
1803
1804 /* handle the case of 'dont filter this module' */
1805 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1806 buff[0] = 0;
1807 not = 1;
1808 }
1809
1810 if (strlen(buff)) {
1811 type = filter_parse_regex(buff, strlen(buff), &search, &not);
1812 search_len = strlen(search);
1813 }
1814
1815 mutex_lock(&ftrace_lock);
1816 do_for_each_ftrace_rec(pg, rec) {
1817
1818 if (rec->flags & FTRACE_FL_FAILED)
1819 continue;
1820
1821 if (ftrace_match_module_record(rec, mod,
1822 search, search_len, type)) {
1823 if (not)
1824 rec->flags &= ~flag;
1825 else
1826 rec->flags |= flag;
1827 found = 1;
1828 }
1829 if (enable && (rec->flags & FTRACE_FL_FILTER))
1830 ftrace_filtered = 1;
1831
1832 } while_for_each_ftrace_rec();
1833 mutex_unlock(&ftrace_lock);
1834
1835 return found;
1836 }
1837
1838 /*
1839 * We register the module command as a template to show others how
1840 * to register the a command as well.
1841 */
1842
1843 static int
1844 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1845 {
1846 char *mod;
1847
1848 /*
1849 * cmd == 'mod' because we only registered this func
1850 * for the 'mod' ftrace_func_command.
1851 * But if you register one func with multiple commands,
1852 * you can tell which command was used by the cmd
1853 * parameter.
1854 */
1855
1856 /* we must have a module name */
1857 if (!param)
1858 return -EINVAL;
1859
1860 mod = strsep(&param, ":");
1861 if (!strlen(mod))
1862 return -EINVAL;
1863
1864 if (ftrace_match_module_records(func, mod, enable))
1865 return 0;
1866 return -EINVAL;
1867 }
1868
1869 static struct ftrace_func_command ftrace_mod_cmd = {
1870 .name = "mod",
1871 .func = ftrace_mod_callback,
1872 };
1873
1874 static int __init ftrace_mod_cmd_init(void)
1875 {
1876 return register_ftrace_command(&ftrace_mod_cmd);
1877 }
1878 device_initcall(ftrace_mod_cmd_init);
1879
1880 static void
1881 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1882 {
1883 struct ftrace_func_probe *entry;
1884 struct hlist_head *hhd;
1885 struct hlist_node *n;
1886 unsigned long key;
1887 int resched;
1888
1889 key = hash_long(ip, FTRACE_HASH_BITS);
1890
1891 hhd = &ftrace_func_hash[key];
1892
1893 if (hlist_empty(hhd))
1894 return;
1895
1896 /*
1897 * Disable preemption for these calls to prevent a RCU grace
1898 * period. This syncs the hash iteration and freeing of items
1899 * on the hash. rcu_read_lock is too dangerous here.
1900 */
1901 resched = ftrace_preempt_disable();
1902 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1903 if (entry->ip == ip)
1904 entry->ops->func(ip, parent_ip, &entry->data);
1905 }
1906 ftrace_preempt_enable(resched);
1907 }
1908
1909 static struct ftrace_ops trace_probe_ops __read_mostly =
1910 {
1911 .func = function_trace_probe_call,
1912 };
1913
1914 static int ftrace_probe_registered;
1915
1916 static void __enable_ftrace_function_probe(void)
1917 {
1918 int i;
1919
1920 if (ftrace_probe_registered)
1921 return;
1922
1923 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1924 struct hlist_head *hhd = &ftrace_func_hash[i];
1925 if (hhd->first)
1926 break;
1927 }
1928 /* Nothing registered? */
1929 if (i == FTRACE_FUNC_HASHSIZE)
1930 return;
1931
1932 __register_ftrace_function(&trace_probe_ops);
1933 ftrace_startup(0);
1934 ftrace_probe_registered = 1;
1935 }
1936
1937 static void __disable_ftrace_function_probe(void)
1938 {
1939 int i;
1940
1941 if (!ftrace_probe_registered)
1942 return;
1943
1944 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1945 struct hlist_head *hhd = &ftrace_func_hash[i];
1946 if (hhd->first)
1947 return;
1948 }
1949
1950 /* no more funcs left */
1951 __unregister_ftrace_function(&trace_probe_ops);
1952 ftrace_shutdown(0);
1953 ftrace_probe_registered = 0;
1954 }
1955
1956
1957 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1958 {
1959 struct ftrace_func_probe *entry =
1960 container_of(rhp, struct ftrace_func_probe, rcu);
1961
1962 if (entry->ops->free)
1963 entry->ops->free(&entry->data);
1964 kfree(entry);
1965 }
1966
1967
1968 int
1969 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1970 void *data)
1971 {
1972 struct ftrace_func_probe *entry;
1973 struct ftrace_page *pg;
1974 struct dyn_ftrace *rec;
1975 int type, len, not;
1976 unsigned long key;
1977 int count = 0;
1978 char *search;
1979
1980 type = filter_parse_regex(glob, strlen(glob), &search, &not);
1981 len = strlen(search);
1982
1983 /* we do not support '!' for function probes */
1984 if (WARN_ON(not))
1985 return -EINVAL;
1986
1987 mutex_lock(&ftrace_lock);
1988 do_for_each_ftrace_rec(pg, rec) {
1989
1990 if (rec->flags & FTRACE_FL_FAILED)
1991 continue;
1992
1993 if (!ftrace_match_record(rec, search, len, type))
1994 continue;
1995
1996 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1997 if (!entry) {
1998 /* If we did not process any, then return error */
1999 if (!count)
2000 count = -ENOMEM;
2001 goto out_unlock;
2002 }
2003
2004 count++;
2005
2006 entry->data = data;
2007
2008 /*
2009 * The caller might want to do something special
2010 * for each function we find. We call the callback
2011 * to give the caller an opportunity to do so.
2012 */
2013 if (ops->callback) {
2014 if (ops->callback(rec->ip, &entry->data) < 0) {
2015 /* caller does not like this func */
2016 kfree(entry);
2017 continue;
2018 }
2019 }
2020
2021 entry->ops = ops;
2022 entry->ip = rec->ip;
2023
2024 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2025 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2026
2027 } while_for_each_ftrace_rec();
2028 __enable_ftrace_function_probe();
2029
2030 out_unlock:
2031 mutex_unlock(&ftrace_lock);
2032
2033 return count;
2034 }
2035
2036 enum {
2037 PROBE_TEST_FUNC = 1,
2038 PROBE_TEST_DATA = 2
2039 };
2040
2041 static void
2042 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2043 void *data, int flags)
2044 {
2045 struct ftrace_func_probe *entry;
2046 struct hlist_node *n, *tmp;
2047 char str[KSYM_SYMBOL_LEN];
2048 int type = MATCH_FULL;
2049 int i, len = 0;
2050 char *search;
2051
2052 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2053 glob = NULL;
2054 else if (glob) {
2055 int not;
2056
2057 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2058 len = strlen(search);
2059
2060 /* we do not support '!' for function probes */
2061 if (WARN_ON(not))
2062 return;
2063 }
2064
2065 mutex_lock(&ftrace_lock);
2066 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2067 struct hlist_head *hhd = &ftrace_func_hash[i];
2068
2069 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2070
2071 /* break up if statements for readability */
2072 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2073 continue;
2074
2075 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2076 continue;
2077
2078 /* do this last, since it is the most expensive */
2079 if (glob) {
2080 kallsyms_lookup(entry->ip, NULL, NULL,
2081 NULL, str);
2082 if (!ftrace_match(str, glob, len, type))
2083 continue;
2084 }
2085
2086 hlist_del(&entry->node);
2087 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2088 }
2089 }
2090 __disable_ftrace_function_probe();
2091 mutex_unlock(&ftrace_lock);
2092 }
2093
2094 void
2095 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2096 void *data)
2097 {
2098 __unregister_ftrace_function_probe(glob, ops, data,
2099 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2100 }
2101
2102 void
2103 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2104 {
2105 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2106 }
2107
2108 void unregister_ftrace_function_probe_all(char *glob)
2109 {
2110 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2111 }
2112
2113 static LIST_HEAD(ftrace_commands);
2114 static DEFINE_MUTEX(ftrace_cmd_mutex);
2115
2116 int register_ftrace_command(struct ftrace_func_command *cmd)
2117 {
2118 struct ftrace_func_command *p;
2119 int ret = 0;
2120
2121 mutex_lock(&ftrace_cmd_mutex);
2122 list_for_each_entry(p, &ftrace_commands, list) {
2123 if (strcmp(cmd->name, p->name) == 0) {
2124 ret = -EBUSY;
2125 goto out_unlock;
2126 }
2127 }
2128 list_add(&cmd->list, &ftrace_commands);
2129 out_unlock:
2130 mutex_unlock(&ftrace_cmd_mutex);
2131
2132 return ret;
2133 }
2134
2135 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2136 {
2137 struct ftrace_func_command *p, *n;
2138 int ret = -ENODEV;
2139
2140 mutex_lock(&ftrace_cmd_mutex);
2141 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2142 if (strcmp(cmd->name, p->name) == 0) {
2143 ret = 0;
2144 list_del_init(&p->list);
2145 goto out_unlock;
2146 }
2147 }
2148 out_unlock:
2149 mutex_unlock(&ftrace_cmd_mutex);
2150
2151 return ret;
2152 }
2153
2154 static int ftrace_process_regex(char *buff, int len, int enable)
2155 {
2156 char *func, *command, *next = buff;
2157 struct ftrace_func_command *p;
2158 int ret = -EINVAL;
2159
2160 func = strsep(&next, ":");
2161
2162 if (!next) {
2163 if (ftrace_match_records(func, len, enable))
2164 return 0;
2165 return ret;
2166 }
2167
2168 /* command found */
2169
2170 command = strsep(&next, ":");
2171
2172 mutex_lock(&ftrace_cmd_mutex);
2173 list_for_each_entry(p, &ftrace_commands, list) {
2174 if (strcmp(p->name, command) == 0) {
2175 ret = p->func(func, command, next, enable);
2176 goto out_unlock;
2177 }
2178 }
2179 out_unlock:
2180 mutex_unlock(&ftrace_cmd_mutex);
2181
2182 return ret;
2183 }
2184
2185 static ssize_t
2186 ftrace_regex_write(struct file *file, const char __user *ubuf,
2187 size_t cnt, loff_t *ppos, int enable)
2188 {
2189 struct ftrace_iterator *iter;
2190 struct trace_parser *parser;
2191 ssize_t ret, read;
2192
2193 if (!cnt)
2194 return 0;
2195
2196 mutex_lock(&ftrace_regex_lock);
2197
2198 if (file->f_mode & FMODE_READ) {
2199 struct seq_file *m = file->private_data;
2200 iter = m->private;
2201 } else
2202 iter = file->private_data;
2203
2204 parser = &iter->parser;
2205 read = trace_get_user(parser, ubuf, cnt, ppos);
2206
2207 if (read >= 0 && trace_parser_loaded(parser) &&
2208 !trace_parser_cont(parser)) {
2209 ret = ftrace_process_regex(parser->buffer,
2210 parser->idx, enable);
2211 trace_parser_clear(parser);
2212 if (ret)
2213 goto out_unlock;
2214 }
2215
2216 ret = read;
2217 out_unlock:
2218 mutex_unlock(&ftrace_regex_lock);
2219
2220 return ret;
2221 }
2222
2223 static ssize_t
2224 ftrace_filter_write(struct file *file, const char __user *ubuf,
2225 size_t cnt, loff_t *ppos)
2226 {
2227 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2228 }
2229
2230 static ssize_t
2231 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2232 size_t cnt, loff_t *ppos)
2233 {
2234 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2235 }
2236
2237 static void
2238 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2239 {
2240 if (unlikely(ftrace_disabled))
2241 return;
2242
2243 mutex_lock(&ftrace_regex_lock);
2244 if (reset)
2245 ftrace_filter_reset(enable);
2246 if (buf)
2247 ftrace_match_records(buf, len, enable);
2248 mutex_unlock(&ftrace_regex_lock);
2249 }
2250
2251 /**
2252 * ftrace_set_filter - set a function to filter on in ftrace
2253 * @buf - the string that holds the function filter text.
2254 * @len - the length of the string.
2255 * @reset - non zero to reset all filters before applying this filter.
2256 *
2257 * Filters denote which functions should be enabled when tracing is enabled.
2258 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2259 */
2260 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2261 {
2262 ftrace_set_regex(buf, len, reset, 1);
2263 }
2264
2265 /**
2266 * ftrace_set_notrace - set a function to not trace in ftrace
2267 * @buf - the string that holds the function notrace text.
2268 * @len - the length of the string.
2269 * @reset - non zero to reset all filters before applying this filter.
2270 *
2271 * Notrace Filters denote which functions should not be enabled when tracing
2272 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2273 * for tracing.
2274 */
2275 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2276 {
2277 ftrace_set_regex(buf, len, reset, 0);
2278 }
2279
2280 /*
2281 * command line interface to allow users to set filters on boot up.
2282 */
2283 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2284 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2285 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2286
2287 static int __init set_ftrace_notrace(char *str)
2288 {
2289 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2290 return 1;
2291 }
2292 __setup("ftrace_notrace=", set_ftrace_notrace);
2293
2294 static int __init set_ftrace_filter(char *str)
2295 {
2296 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2297 return 1;
2298 }
2299 __setup("ftrace_filter=", set_ftrace_filter);
2300
2301 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2302 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2303 static int __init set_graph_function(char *str)
2304 {
2305 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2306 return 1;
2307 }
2308 __setup("ftrace_graph_filter=", set_graph_function);
2309
2310 static void __init set_ftrace_early_graph(char *buf)
2311 {
2312 int ret;
2313 char *func;
2314
2315 while (buf) {
2316 func = strsep(&buf, ",");
2317 /* we allow only one expression at a time */
2318 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2319 func);
2320 if (ret)
2321 printk(KERN_DEBUG "ftrace: function %s not "
2322 "traceable\n", func);
2323 }
2324 }
2325 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2326
2327 static void __init set_ftrace_early_filter(char *buf, int enable)
2328 {
2329 char *func;
2330
2331 while (buf) {
2332 func = strsep(&buf, ",");
2333 ftrace_set_regex(func, strlen(func), 0, enable);
2334 }
2335 }
2336
2337 static void __init set_ftrace_early_filters(void)
2338 {
2339 if (ftrace_filter_buf[0])
2340 set_ftrace_early_filter(ftrace_filter_buf, 1);
2341 if (ftrace_notrace_buf[0])
2342 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2343 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2344 if (ftrace_graph_buf[0])
2345 set_ftrace_early_graph(ftrace_graph_buf);
2346 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2347 }
2348
2349 static int
2350 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2351 {
2352 struct seq_file *m = (struct seq_file *)file->private_data;
2353 struct ftrace_iterator *iter;
2354 struct trace_parser *parser;
2355
2356 mutex_lock(&ftrace_regex_lock);
2357 if (file->f_mode & FMODE_READ) {
2358 iter = m->private;
2359
2360 seq_release(inode, file);
2361 } else
2362 iter = file->private_data;
2363
2364 parser = &iter->parser;
2365 if (trace_parser_loaded(parser)) {
2366 parser->buffer[parser->idx] = 0;
2367 ftrace_match_records(parser->buffer, parser->idx, enable);
2368 }
2369
2370 mutex_lock(&ftrace_lock);
2371 if (ftrace_start_up && ftrace_enabled)
2372 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2373 mutex_unlock(&ftrace_lock);
2374
2375 trace_parser_put(parser);
2376 kfree(iter);
2377
2378 mutex_unlock(&ftrace_regex_lock);
2379 return 0;
2380 }
2381
2382 static int
2383 ftrace_filter_release(struct inode *inode, struct file *file)
2384 {
2385 return ftrace_regex_release(inode, file, 1);
2386 }
2387
2388 static int
2389 ftrace_notrace_release(struct inode *inode, struct file *file)
2390 {
2391 return ftrace_regex_release(inode, file, 0);
2392 }
2393
2394 static const struct file_operations ftrace_avail_fops = {
2395 .open = ftrace_avail_open,
2396 .read = seq_read,
2397 .llseek = seq_lseek,
2398 .release = seq_release_private,
2399 };
2400
2401 static const struct file_operations ftrace_failures_fops = {
2402 .open = ftrace_failures_open,
2403 .read = seq_read,
2404 .llseek = seq_lseek,
2405 .release = seq_release_private,
2406 };
2407
2408 static const struct file_operations ftrace_filter_fops = {
2409 .open = ftrace_filter_open,
2410 .read = seq_read,
2411 .write = ftrace_filter_write,
2412 .llseek = ftrace_regex_lseek,
2413 .release = ftrace_filter_release,
2414 };
2415
2416 static const struct file_operations ftrace_notrace_fops = {
2417 .open = ftrace_notrace_open,
2418 .read = seq_read,
2419 .write = ftrace_notrace_write,
2420 .llseek = ftrace_regex_lseek,
2421 .release = ftrace_notrace_release,
2422 };
2423
2424 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2425
2426 static DEFINE_MUTEX(graph_lock);
2427
2428 int ftrace_graph_count;
2429 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2430
2431 static void *
2432 __g_next(struct seq_file *m, loff_t *pos)
2433 {
2434 if (*pos >= ftrace_graph_count)
2435 return NULL;
2436 return &ftrace_graph_funcs[*pos];
2437 }
2438
2439 static void *
2440 g_next(struct seq_file *m, void *v, loff_t *pos)
2441 {
2442 (*pos)++;
2443 return __g_next(m, pos);
2444 }
2445
2446 static void *g_start(struct seq_file *m, loff_t *pos)
2447 {
2448 mutex_lock(&graph_lock);
2449
2450 /* Nothing, tell g_show to print all functions are enabled */
2451 if (!ftrace_graph_count && !*pos)
2452 return (void *)1;
2453
2454 return __g_next(m, pos);
2455 }
2456
2457 static void g_stop(struct seq_file *m, void *p)
2458 {
2459 mutex_unlock(&graph_lock);
2460 }
2461
2462 static int g_show(struct seq_file *m, void *v)
2463 {
2464 unsigned long *ptr = v;
2465
2466 if (!ptr)
2467 return 0;
2468
2469 if (ptr == (unsigned long *)1) {
2470 seq_printf(m, "#### all functions enabled ####\n");
2471 return 0;
2472 }
2473
2474 seq_printf(m, "%ps\n", (void *)*ptr);
2475
2476 return 0;
2477 }
2478
2479 static const struct seq_operations ftrace_graph_seq_ops = {
2480 .start = g_start,
2481 .next = g_next,
2482 .stop = g_stop,
2483 .show = g_show,
2484 };
2485
2486 static int
2487 ftrace_graph_open(struct inode *inode, struct file *file)
2488 {
2489 int ret = 0;
2490
2491 if (unlikely(ftrace_disabled))
2492 return -ENODEV;
2493
2494 mutex_lock(&graph_lock);
2495 if ((file->f_mode & FMODE_WRITE) &&
2496 (file->f_flags & O_TRUNC)) {
2497 ftrace_graph_count = 0;
2498 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2499 }
2500 mutex_unlock(&graph_lock);
2501
2502 if (file->f_mode & FMODE_READ)
2503 ret = seq_open(file, &ftrace_graph_seq_ops);
2504
2505 return ret;
2506 }
2507
2508 static int
2509 ftrace_graph_release(struct inode *inode, struct file *file)
2510 {
2511 if (file->f_mode & FMODE_READ)
2512 seq_release(inode, file);
2513 return 0;
2514 }
2515
2516 static int
2517 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2518 {
2519 struct dyn_ftrace *rec;
2520 struct ftrace_page *pg;
2521 int search_len;
2522 int found = 0;
2523 int type, not;
2524 char *search;
2525 bool exists;
2526 int i;
2527
2528 if (ftrace_disabled)
2529 return -ENODEV;
2530
2531 /* decode regex */
2532 type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
2533 if (not)
2534 return -EINVAL;
2535
2536 search_len = strlen(search);
2537
2538 mutex_lock(&ftrace_lock);
2539 do_for_each_ftrace_rec(pg, rec) {
2540
2541 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2542 break;
2543
2544 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2545 continue;
2546
2547 if (ftrace_match_record(rec, search, search_len, type)) {
2548 /* ensure it is not already in the array */
2549 exists = false;
2550 for (i = 0; i < *idx; i++)
2551 if (array[i] == rec->ip) {
2552 exists = true;
2553 break;
2554 }
2555 if (!exists)
2556 array[(*idx)++] = rec->ip;
2557 found = 1;
2558 }
2559 } while_for_each_ftrace_rec();
2560
2561 mutex_unlock(&ftrace_lock);
2562
2563 return found ? 0 : -EINVAL;
2564 }
2565
2566 static ssize_t
2567 ftrace_graph_write(struct file *file, const char __user *ubuf,
2568 size_t cnt, loff_t *ppos)
2569 {
2570 struct trace_parser parser;
2571 ssize_t read, ret;
2572
2573 if (!cnt || cnt < 0)
2574 return 0;
2575
2576 mutex_lock(&graph_lock);
2577
2578 if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2579 ret = -EBUSY;
2580 goto out_unlock;
2581 }
2582
2583 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2584 ret = -ENOMEM;
2585 goto out_unlock;
2586 }
2587
2588 read = trace_get_user(&parser, ubuf, cnt, ppos);
2589
2590 if (read >= 0 && trace_parser_loaded((&parser))) {
2591 parser.buffer[parser.idx] = 0;
2592
2593 /* we allow only one expression at a time */
2594 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2595 parser.buffer);
2596 if (ret)
2597 goto out_free;
2598 }
2599
2600 ret = read;
2601
2602 out_free:
2603 trace_parser_put(&parser);
2604 out_unlock:
2605 mutex_unlock(&graph_lock);
2606
2607 return ret;
2608 }
2609
2610 static const struct file_operations ftrace_graph_fops = {
2611 .open = ftrace_graph_open,
2612 .read = seq_read,
2613 .write = ftrace_graph_write,
2614 .release = ftrace_graph_release,
2615 };
2616 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2617
2618 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2619 {
2620
2621 trace_create_file("available_filter_functions", 0444,
2622 d_tracer, NULL, &ftrace_avail_fops);
2623
2624 trace_create_file("failures", 0444,
2625 d_tracer, NULL, &ftrace_failures_fops);
2626
2627 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2628 NULL, &ftrace_filter_fops);
2629
2630 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2631 NULL, &ftrace_notrace_fops);
2632
2633 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2634 trace_create_file("set_graph_function", 0444, d_tracer,
2635 NULL,
2636 &ftrace_graph_fops);
2637 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2638
2639 return 0;
2640 }
2641
2642 static int ftrace_process_locs(struct module *mod,
2643 unsigned long *start,
2644 unsigned long *end)
2645 {
2646 unsigned long *p;
2647 unsigned long addr;
2648 unsigned long flags;
2649
2650 mutex_lock(&ftrace_lock);
2651 p = start;
2652 while (p < end) {
2653 addr = ftrace_call_adjust(*p++);
2654 /*
2655 * Some architecture linkers will pad between
2656 * the different mcount_loc sections of different
2657 * object files to satisfy alignments.
2658 * Skip any NULL pointers.
2659 */
2660 if (!addr)
2661 continue;
2662 ftrace_record_ip(addr);
2663 }
2664
2665 /* disable interrupts to prevent kstop machine */
2666 local_irq_save(flags);
2667 ftrace_update_code(mod);
2668 local_irq_restore(flags);
2669 mutex_unlock(&ftrace_lock);
2670
2671 return 0;
2672 }
2673
2674 #ifdef CONFIG_MODULES
2675 void ftrace_release_mod(struct module *mod)
2676 {
2677 struct dyn_ftrace *rec;
2678 struct ftrace_page *pg;
2679
2680 if (ftrace_disabled)
2681 return;
2682
2683 mutex_lock(&ftrace_lock);
2684 do_for_each_ftrace_rec(pg, rec) {
2685 if (within_module_core(rec->ip, mod)) {
2686 /*
2687 * rec->ip is changed in ftrace_free_rec()
2688 * It should not between s and e if record was freed.
2689 */
2690 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2691 ftrace_free_rec(rec);
2692 }
2693 } while_for_each_ftrace_rec();
2694 mutex_unlock(&ftrace_lock);
2695 }
2696
2697 static void ftrace_init_module(struct module *mod,
2698 unsigned long *start, unsigned long *end)
2699 {
2700 if (ftrace_disabled || start == end)
2701 return;
2702 ftrace_process_locs(mod, start, end);
2703 }
2704
2705 static int ftrace_module_notify(struct notifier_block *self,
2706 unsigned long val, void *data)
2707 {
2708 struct module *mod = data;
2709
2710 switch (val) {
2711 case MODULE_STATE_COMING:
2712 ftrace_init_module(mod, mod->ftrace_callsites,
2713 mod->ftrace_callsites +
2714 mod->num_ftrace_callsites);
2715 break;
2716 case MODULE_STATE_GOING:
2717 ftrace_release_mod(mod);
2718 break;
2719 }
2720
2721 return 0;
2722 }
2723 #else
2724 static int ftrace_module_notify(struct notifier_block *self,
2725 unsigned long val, void *data)
2726 {
2727 return 0;
2728 }
2729 #endif /* CONFIG_MODULES */
2730
2731 struct notifier_block ftrace_module_nb = {
2732 .notifier_call = ftrace_module_notify,
2733 .priority = 0,
2734 };
2735
2736 extern unsigned long __start_mcount_loc[];
2737 extern unsigned long __stop_mcount_loc[];
2738
2739 void __init ftrace_init(void)
2740 {
2741 unsigned long count, addr, flags;
2742 int ret;
2743
2744 /* Keep the ftrace pointer to the stub */
2745 addr = (unsigned long)ftrace_stub;
2746
2747 local_irq_save(flags);
2748 ftrace_dyn_arch_init(&addr);
2749 local_irq_restore(flags);
2750
2751 /* ftrace_dyn_arch_init places the return code in addr */
2752 if (addr)
2753 goto failed;
2754
2755 count = __stop_mcount_loc - __start_mcount_loc;
2756
2757 ret = ftrace_dyn_table_alloc(count);
2758 if (ret)
2759 goto failed;
2760
2761 last_ftrace_enabled = ftrace_enabled = 1;
2762
2763 ret = ftrace_process_locs(NULL,
2764 __start_mcount_loc,
2765 __stop_mcount_loc);
2766
2767 ret = register_module_notifier(&ftrace_module_nb);
2768 if (ret)
2769 pr_warning("Failed to register trace ftrace module notifier\n");
2770
2771 set_ftrace_early_filters();
2772
2773 return;
2774 failed:
2775 ftrace_disabled = 1;
2776 }
2777
2778 #else
2779
2780 static int __init ftrace_nodyn_init(void)
2781 {
2782 ftrace_enabled = 1;
2783 return 0;
2784 }
2785 device_initcall(ftrace_nodyn_init);
2786
2787 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2788 static inline void ftrace_startup_enable(int command) { }
2789 /* Keep as macros so we do not need to define the commands */
2790 # define ftrace_startup(command) do { } while (0)
2791 # define ftrace_shutdown(command) do { } while (0)
2792 # define ftrace_startup_sysctl() do { } while (0)
2793 # define ftrace_shutdown_sysctl() do { } while (0)
2794 #endif /* CONFIG_DYNAMIC_FTRACE */
2795
2796 static void clear_ftrace_swapper(void)
2797 {
2798 struct task_struct *p;
2799 int cpu;
2800
2801 get_online_cpus();
2802 for_each_online_cpu(cpu) {
2803 p = idle_task(cpu);
2804 clear_tsk_trace_trace(p);
2805 }
2806 put_online_cpus();
2807 }
2808
2809 static void set_ftrace_swapper(void)
2810 {
2811 struct task_struct *p;
2812 int cpu;
2813
2814 get_online_cpus();
2815 for_each_online_cpu(cpu) {
2816 p = idle_task(cpu);
2817 set_tsk_trace_trace(p);
2818 }
2819 put_online_cpus();
2820 }
2821
2822 static void clear_ftrace_pid(struct pid *pid)
2823 {
2824 struct task_struct *p;
2825
2826 rcu_read_lock();
2827 do_each_pid_task(pid, PIDTYPE_PID, p) {
2828 clear_tsk_trace_trace(p);
2829 } while_each_pid_task(pid, PIDTYPE_PID, p);
2830 rcu_read_unlock();
2831
2832 put_pid(pid);
2833 }
2834
2835 static void set_ftrace_pid(struct pid *pid)
2836 {
2837 struct task_struct *p;
2838
2839 rcu_read_lock();
2840 do_each_pid_task(pid, PIDTYPE_PID, p) {
2841 set_tsk_trace_trace(p);
2842 } while_each_pid_task(pid, PIDTYPE_PID, p);
2843 rcu_read_unlock();
2844 }
2845
2846 static void clear_ftrace_pid_task(struct pid *pid)
2847 {
2848 if (pid == ftrace_swapper_pid)
2849 clear_ftrace_swapper();
2850 else
2851 clear_ftrace_pid(pid);
2852 }
2853
2854 static void set_ftrace_pid_task(struct pid *pid)
2855 {
2856 if (pid == ftrace_swapper_pid)
2857 set_ftrace_swapper();
2858 else
2859 set_ftrace_pid(pid);
2860 }
2861
2862 static int ftrace_pid_add(int p)
2863 {
2864 struct pid *pid;
2865 struct ftrace_pid *fpid;
2866 int ret = -EINVAL;
2867
2868 mutex_lock(&ftrace_lock);
2869
2870 if (!p)
2871 pid = ftrace_swapper_pid;
2872 else
2873 pid = find_get_pid(p);
2874
2875 if (!pid)
2876 goto out;
2877
2878 ret = 0;
2879
2880 list_for_each_entry(fpid, &ftrace_pids, list)
2881 if (fpid->pid == pid)
2882 goto out_put;
2883
2884 ret = -ENOMEM;
2885
2886 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2887 if (!fpid)
2888 goto out_put;
2889
2890 list_add(&fpid->list, &ftrace_pids);
2891 fpid->pid = pid;
2892
2893 set_ftrace_pid_task(pid);
2894
2895 ftrace_update_pid_func();
2896 ftrace_startup_enable(0);
2897
2898 mutex_unlock(&ftrace_lock);
2899 return 0;
2900
2901 out_put:
2902 if (pid != ftrace_swapper_pid)
2903 put_pid(pid);
2904
2905 out:
2906 mutex_unlock(&ftrace_lock);
2907 return ret;
2908 }
2909
2910 static void ftrace_pid_reset(void)
2911 {
2912 struct ftrace_pid *fpid, *safe;
2913
2914 mutex_lock(&ftrace_lock);
2915 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2916 struct pid *pid = fpid->pid;
2917
2918 clear_ftrace_pid_task(pid);
2919
2920 list_del(&fpid->list);
2921 kfree(fpid);
2922 }
2923
2924 ftrace_update_pid_func();
2925 ftrace_startup_enable(0);
2926
2927 mutex_unlock(&ftrace_lock);
2928 }
2929
2930 static void *fpid_start(struct seq_file *m, loff_t *pos)
2931 {
2932 mutex_lock(&ftrace_lock);
2933
2934 if (list_empty(&ftrace_pids) && (!*pos))
2935 return (void *) 1;
2936
2937 return seq_list_start(&ftrace_pids, *pos);
2938 }
2939
2940 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
2941 {
2942 if (v == (void *)1)
2943 return NULL;
2944
2945 return seq_list_next(v, &ftrace_pids, pos);
2946 }
2947
2948 static void fpid_stop(struct seq_file *m, void *p)
2949 {
2950 mutex_unlock(&ftrace_lock);
2951 }
2952
2953 static int fpid_show(struct seq_file *m, void *v)
2954 {
2955 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
2956
2957 if (v == (void *)1) {
2958 seq_printf(m, "no pid\n");
2959 return 0;
2960 }
2961
2962 if (fpid->pid == ftrace_swapper_pid)
2963 seq_printf(m, "swapper tasks\n");
2964 else
2965 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
2966
2967 return 0;
2968 }
2969
2970 static const struct seq_operations ftrace_pid_sops = {
2971 .start = fpid_start,
2972 .next = fpid_next,
2973 .stop = fpid_stop,
2974 .show = fpid_show,
2975 };
2976
2977 static int
2978 ftrace_pid_open(struct inode *inode, struct file *file)
2979 {
2980 int ret = 0;
2981
2982 if ((file->f_mode & FMODE_WRITE) &&
2983 (file->f_flags & O_TRUNC))
2984 ftrace_pid_reset();
2985
2986 if (file->f_mode & FMODE_READ)
2987 ret = seq_open(file, &ftrace_pid_sops);
2988
2989 return ret;
2990 }
2991
2992 static ssize_t
2993 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2994 size_t cnt, loff_t *ppos)
2995 {
2996 char buf[64], *tmp;
2997 long val;
2998 int ret;
2999
3000 if (cnt >= sizeof(buf))
3001 return -EINVAL;
3002
3003 if (copy_from_user(&buf, ubuf, cnt))
3004 return -EFAULT;
3005
3006 buf[cnt] = 0;
3007
3008 /*
3009 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3010 * to clean the filter quietly.
3011 */
3012 tmp = strstrip(buf);
3013 if (strlen(tmp) == 0)
3014 return 1;
3015
3016 ret = strict_strtol(tmp, 10, &val);
3017 if (ret < 0)
3018 return ret;
3019
3020 ret = ftrace_pid_add(val);
3021
3022 return ret ? ret : cnt;
3023 }
3024
3025 static int
3026 ftrace_pid_release(struct inode *inode, struct file *file)
3027 {
3028 if (file->f_mode & FMODE_READ)
3029 seq_release(inode, file);
3030
3031 return 0;
3032 }
3033
3034 static const struct file_operations ftrace_pid_fops = {
3035 .open = ftrace_pid_open,
3036 .write = ftrace_pid_write,
3037 .read = seq_read,
3038 .llseek = seq_lseek,
3039 .release = ftrace_pid_release,
3040 };
3041
3042 static __init int ftrace_init_debugfs(void)
3043 {
3044 struct dentry *d_tracer;
3045
3046 d_tracer = tracing_init_dentry();
3047 if (!d_tracer)
3048 return 0;
3049
3050 ftrace_init_dyn_debugfs(d_tracer);
3051
3052 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3053 NULL, &ftrace_pid_fops);
3054
3055 ftrace_profile_debugfs(d_tracer);
3056
3057 return 0;
3058 }
3059 fs_initcall(ftrace_init_debugfs);
3060
3061 /**
3062 * ftrace_kill - kill ftrace
3063 *
3064 * This function should be used by panic code. It stops ftrace
3065 * but in a not so nice way. If you need to simply kill ftrace
3066 * from a non-atomic section, use ftrace_kill.
3067 */
3068 void ftrace_kill(void)
3069 {
3070 ftrace_disabled = 1;
3071 ftrace_enabled = 0;
3072 clear_ftrace_function();
3073 }
3074
3075 /**
3076 * register_ftrace_function - register a function for profiling
3077 * @ops - ops structure that holds the function for profiling.
3078 *
3079 * Register a function to be called by all functions in the
3080 * kernel.
3081 *
3082 * Note: @ops->func and all the functions it calls must be labeled
3083 * with "notrace", otherwise it will go into a
3084 * recursive loop.
3085 */
3086 int register_ftrace_function(struct ftrace_ops *ops)
3087 {
3088 int ret;
3089
3090 if (unlikely(ftrace_disabled))
3091 return -1;
3092
3093 mutex_lock(&ftrace_lock);
3094
3095 ret = __register_ftrace_function(ops);
3096 ftrace_startup(0);
3097
3098 mutex_unlock(&ftrace_lock);
3099 return ret;
3100 }
3101
3102 /**
3103 * unregister_ftrace_function - unregister a function for profiling.
3104 * @ops - ops structure that holds the function to unregister
3105 *
3106 * Unregister a function that was added to be called by ftrace profiling.
3107 */
3108 int unregister_ftrace_function(struct ftrace_ops *ops)
3109 {
3110 int ret;
3111
3112 mutex_lock(&ftrace_lock);
3113 ret = __unregister_ftrace_function(ops);
3114 ftrace_shutdown(0);
3115 mutex_unlock(&ftrace_lock);
3116
3117 return ret;
3118 }
3119
3120 int
3121 ftrace_enable_sysctl(struct ctl_table *table, int write,
3122 void __user *buffer, size_t *lenp,
3123 loff_t *ppos)
3124 {
3125 int ret;
3126
3127 if (unlikely(ftrace_disabled))
3128 return -ENODEV;
3129
3130 mutex_lock(&ftrace_lock);
3131
3132 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3133
3134 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3135 goto out;
3136
3137 last_ftrace_enabled = !!ftrace_enabled;
3138
3139 if (ftrace_enabled) {
3140
3141 ftrace_startup_sysctl();
3142
3143 /* we are starting ftrace again */
3144 if (ftrace_list != &ftrace_list_end) {
3145 if (ftrace_list->next == &ftrace_list_end)
3146 ftrace_trace_function = ftrace_list->func;
3147 else
3148 ftrace_trace_function = ftrace_list_func;
3149 }
3150
3151 } else {
3152 /* stopping ftrace calls (just send to ftrace_stub) */
3153 ftrace_trace_function = ftrace_stub;
3154
3155 ftrace_shutdown_sysctl();
3156 }
3157
3158 out:
3159 mutex_unlock(&ftrace_lock);
3160 return ret;
3161 }
3162
3163 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3164
3165 static int ftrace_graph_active;
3166 static struct notifier_block ftrace_suspend_notifier;
3167
3168 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3169 {
3170 return 0;
3171 }
3172
3173 /* The callbacks that hook a function */
3174 trace_func_graph_ret_t ftrace_graph_return =
3175 (trace_func_graph_ret_t)ftrace_stub;
3176 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3177
3178 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3179 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3180 {
3181 int i;
3182 int ret = 0;
3183 unsigned long flags;
3184 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3185 struct task_struct *g, *t;
3186
3187 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3188 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3189 * sizeof(struct ftrace_ret_stack),
3190 GFP_KERNEL);
3191 if (!ret_stack_list[i]) {
3192 start = 0;
3193 end = i;
3194 ret = -ENOMEM;
3195 goto free;
3196 }
3197 }
3198
3199 read_lock_irqsave(&tasklist_lock, flags);
3200 do_each_thread(g, t) {
3201 if (start == end) {
3202 ret = -EAGAIN;
3203 goto unlock;
3204 }
3205
3206 if (t->ret_stack == NULL) {
3207 atomic_set(&t->tracing_graph_pause, 0);
3208 atomic_set(&t->trace_overrun, 0);
3209 t->curr_ret_stack = -1;
3210 /* Make sure the tasks see the -1 first: */
3211 smp_wmb();
3212 t->ret_stack = ret_stack_list[start++];
3213 }
3214 } while_each_thread(g, t);
3215
3216 unlock:
3217 read_unlock_irqrestore(&tasklist_lock, flags);
3218 free:
3219 for (i = start; i < end; i++)
3220 kfree(ret_stack_list[i]);
3221 return ret;
3222 }
3223
3224 static void
3225 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3226 struct task_struct *next)
3227 {
3228 unsigned long long timestamp;
3229 int index;
3230
3231 /*
3232 * Does the user want to count the time a function was asleep.
3233 * If so, do not update the time stamps.
3234 */
3235 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3236 return;
3237
3238 timestamp = trace_clock_local();
3239
3240 prev->ftrace_timestamp = timestamp;
3241
3242 /* only process tasks that we timestamped */
3243 if (!next->ftrace_timestamp)
3244 return;
3245
3246 /*
3247 * Update all the counters in next to make up for the
3248 * time next was sleeping.
3249 */
3250 timestamp -= next->ftrace_timestamp;
3251
3252 for (index = next->curr_ret_stack; index >= 0; index--)
3253 next->ret_stack[index].calltime += timestamp;
3254 }
3255
3256 /* Allocate a return stack for each task */
3257 static int start_graph_tracing(void)
3258 {
3259 struct ftrace_ret_stack **ret_stack_list;
3260 int ret, cpu;
3261
3262 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3263 sizeof(struct ftrace_ret_stack *),
3264 GFP_KERNEL);
3265
3266 if (!ret_stack_list)
3267 return -ENOMEM;
3268
3269 /* The cpu_boot init_task->ret_stack will never be freed */
3270 for_each_online_cpu(cpu) {
3271 if (!idle_task(cpu)->ret_stack)
3272 ftrace_graph_init_task(idle_task(cpu));
3273 }
3274
3275 do {
3276 ret = alloc_retstack_tasklist(ret_stack_list);
3277 } while (ret == -EAGAIN);
3278
3279 if (!ret) {
3280 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3281 if (ret)
3282 pr_info("ftrace_graph: Couldn't activate tracepoint"
3283 " probe to kernel_sched_switch\n");
3284 }
3285
3286 kfree(ret_stack_list);
3287 return ret;
3288 }
3289
3290 /*
3291 * Hibernation protection.
3292 * The state of the current task is too much unstable during
3293 * suspend/restore to disk. We want to protect against that.
3294 */
3295 static int
3296 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3297 void *unused)
3298 {
3299 switch (state) {
3300 case PM_HIBERNATION_PREPARE:
3301 pause_graph_tracing();
3302 break;
3303
3304 case PM_POST_HIBERNATION:
3305 unpause_graph_tracing();
3306 break;
3307 }
3308 return NOTIFY_DONE;
3309 }
3310
3311 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3312 trace_func_graph_ent_t entryfunc)
3313 {
3314 int ret = 0;
3315
3316 mutex_lock(&ftrace_lock);
3317
3318 /* we currently allow only one tracer registered at a time */
3319 if (ftrace_graph_active) {
3320 ret = -EBUSY;
3321 goto out;
3322 }
3323
3324 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3325 register_pm_notifier(&ftrace_suspend_notifier);
3326
3327 ftrace_graph_active++;
3328 ret = start_graph_tracing();
3329 if (ret) {
3330 ftrace_graph_active--;
3331 goto out;
3332 }
3333
3334 ftrace_graph_return = retfunc;
3335 ftrace_graph_entry = entryfunc;
3336
3337 ftrace_startup(FTRACE_START_FUNC_RET);
3338
3339 out:
3340 mutex_unlock(&ftrace_lock);
3341 return ret;
3342 }
3343
3344 void unregister_ftrace_graph(void)
3345 {
3346 mutex_lock(&ftrace_lock);
3347
3348 if (unlikely(!ftrace_graph_active))
3349 goto out;
3350
3351 ftrace_graph_active--;
3352 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3353 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3354 ftrace_graph_entry = ftrace_graph_entry_stub;
3355 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3356 unregister_pm_notifier(&ftrace_suspend_notifier);
3357
3358 out:
3359 mutex_unlock(&ftrace_lock);
3360 }
3361
3362 /* Allocate a return stack for newly created task */
3363 void ftrace_graph_init_task(struct task_struct *t)
3364 {
3365 /* Make sure we do not use the parent ret_stack */
3366 t->ret_stack = NULL;
3367
3368 if (ftrace_graph_active) {
3369 struct ftrace_ret_stack *ret_stack;
3370
3371 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3372 * sizeof(struct ftrace_ret_stack),
3373 GFP_KERNEL);
3374 if (!ret_stack)
3375 return;
3376 t->curr_ret_stack = -1;
3377 atomic_set(&t->tracing_graph_pause, 0);
3378 atomic_set(&t->trace_overrun, 0);
3379 t->ftrace_timestamp = 0;
3380 /* make curr_ret_stack visable before we add the ret_stack */
3381 smp_wmb();
3382 t->ret_stack = ret_stack;
3383 }
3384 }
3385
3386 void ftrace_graph_exit_task(struct task_struct *t)
3387 {
3388 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3389
3390 t->ret_stack = NULL;
3391 /* NULL must become visible to IRQs before we free it: */
3392 barrier();
3393
3394 kfree(ret_stack);
3395 }
3396
3397 void ftrace_graph_stop(void)
3398 {
3399 ftrace_stop();
3400 }
3401 #endif
linux 2.6 git repository for openrd