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RT-AC56 3.0.0.4.374.37 core
[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / kernel / trace / ftrace.c
blobfa7ece649fe1bcad7b0db621fa8579e91860fb04
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/ftrace.h>
26 #include <linux/sysctl.h>
27 #include <linux/slab.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
31 #include <linux/rcupdate.h>
32
33 #include <trace/events/sched.h>
34
35 #include <asm/ftrace.h>
36 #include <asm/setup.h>
37
38 #include "trace_output.h"
39 #include "trace_stat.h"
40
41 #define FTRACE_WARN_ON(cond) \
42 do { \
43 if (WARN_ON(cond)) \
44 ftrace_kill(); \
45 } while (0)
46
47 #define FTRACE_WARN_ON_ONCE(cond) \
48 do { \
49 if (WARN_ON_ONCE(cond)) \
50 ftrace_kill(); \
51 } while (0)
52
53 /* hash bits for specific function selection */
54 #define FTRACE_HASH_BITS 7
55 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
56
57 /* ftrace_enabled is a method to turn ftrace on or off */
58 int ftrace_enabled __read_mostly;
59 static int last_ftrace_enabled;
60
61 /* Quick disabling of function tracer. */
62 int function_trace_stop;
63
64 /* List for set_ftrace_pid's pids. */
65 LIST_HEAD(ftrace_pids);
66 struct ftrace_pid {
67 struct list_head list;
68 struct pid *pid;
69 };
70
71 /*
72 * ftrace_disabled is set when an anomaly is discovered.
73 * ftrace_disabled is much stronger than ftrace_enabled.
74 */
75 static int ftrace_disabled __read_mostly;
76
77 static DEFINE_MUTEX(ftrace_lock);
78
79 static struct ftrace_ops ftrace_list_end __read_mostly =
80 {
81 .func = ftrace_stub,
82 };
83
84 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
85 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
86 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
87 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
88
89 /*
90 * Traverse the ftrace_list, invoking all entries. The reason that we
91 * can use rcu_dereference_raw() is that elements removed from this list
92 * are simply leaked, so there is no need to interact with a grace-period
93 * mechanism. The rcu_dereference_raw() calls are needed to handle
94 * concurrent insertions into the ftrace_list.
95 *
96 * Silly Alpha and silly pointer-speculation compiler optimizations!
97 */
98 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
99 {
100 struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
101
102 while (op != &ftrace_list_end) {
103 op->func(ip, parent_ip);
104 op = rcu_dereference_raw(op->next); /*see above*/
105 };
106 }
107
108 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
109 {
110 if (!test_tsk_trace_trace(current))
111 return;
112
113 ftrace_pid_function(ip, parent_ip);
114 }
115
116 static void set_ftrace_pid_function(ftrace_func_t func)
117 {
118 /* do not set ftrace_pid_function to itself! */
119 if (func != ftrace_pid_func)
120 ftrace_pid_function = func;
121 }
122
123 /**
124 * clear_ftrace_function - reset the ftrace function
125 *
126 * This NULLs the ftrace function and in essence stops
127 * tracing. There may be lag
128 */
129 void clear_ftrace_function(void)
130 {
131 ftrace_trace_function = ftrace_stub;
132 __ftrace_trace_function = ftrace_stub;
133 ftrace_pid_function = ftrace_stub;
134 }
135
136 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
137 /*
138 * For those archs that do not test ftrace_trace_stop in their
139 * mcount call site, we need to do it from C.
140 */
141 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
142 {
143 if (function_trace_stop)
144 return;
145
146 __ftrace_trace_function(ip, parent_ip);
147 }
148 #endif
149
150 static int __register_ftrace_function(struct ftrace_ops *ops)
151 {
152 ops->next = ftrace_list;
153 /*
154 * We are entering ops into the ftrace_list but another
155 * CPU might be walking that list. We need to make sure
156 * the ops->next pointer is valid before another CPU sees
157 * the ops pointer included into the ftrace_list.
158 */
159 rcu_assign_pointer(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 unsigned long long time_squared;
268 #endif
269 };
270
271 struct ftrace_profile_page {
272 struct ftrace_profile_page *next;
273 unsigned long index;
274 struct ftrace_profile records[];
275 };
276
277 struct ftrace_profile_stat {
278 atomic_t disabled;
279 struct hlist_head *hash;
280 struct ftrace_profile_page *pages;
281 struct ftrace_profile_page *start;
282 struct tracer_stat stat;
283 };
284
285 #define PROFILE_RECORDS_SIZE \
286 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
287
288 #define PROFILES_PER_PAGE \
289 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
290
291 static int ftrace_profile_bits __read_mostly;
292 static int ftrace_profile_enabled __read_mostly;
293
294 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
295 static DEFINE_MUTEX(ftrace_profile_lock);
296
297 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
298
299 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
300
301 static void *
302 function_stat_next(void *v, int idx)
303 {
304 struct ftrace_profile *rec = v;
305 struct ftrace_profile_page *pg;
306
307 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
308
309 again:
310 if (idx != 0)
311 rec++;
312
313 if ((void *)rec >= (void *)&pg->records[pg->index]) {
314 pg = pg->next;
315 if (!pg)
316 return NULL;
317 rec = &pg->records[0];
318 if (!rec->counter)
319 goto again;
320 }
321
322 return rec;
323 }
324
325 static void *function_stat_start(struct tracer_stat *trace)
326 {
327 struct ftrace_profile_stat *stat =
328 container_of(trace, struct ftrace_profile_stat, stat);
329
330 if (!stat || !stat->start)
331 return NULL;
332
333 return function_stat_next(&stat->start->records[0], 0);
334 }
335
336 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
337 /* function graph compares on total time */
338 static int function_stat_cmp(void *p1, void *p2)
339 {
340 struct ftrace_profile *a = p1;
341 struct ftrace_profile *b = p2;
342
343 if (a->time < b->time)
344 return -1;
345 if (a->time > b->time)
346 return 1;
347 else
348 return 0;
349 }
350 #else
351 /* not function graph compares against hits */
352 static int function_stat_cmp(void *p1, void *p2)
353 {
354 struct ftrace_profile *a = p1;
355 struct ftrace_profile *b = p2;
356
357 if (a->counter < b->counter)
358 return -1;
359 if (a->counter > b->counter)
360 return 1;
361 else
362 return 0;
363 }
364 #endif
365
366 static int function_stat_headers(struct seq_file *m)
367 {
368 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
369 seq_printf(m, " Function "
370 "Hit Time Avg s^2\n"
371 " -------- "
372 "--- ---- --- ---\n");
373 #else
374 seq_printf(m, " Function Hit\n"
375 " -------- ---\n");
376 #endif
377 return 0;
378 }
379
380 static int function_stat_show(struct seq_file *m, void *v)
381 {
382 struct ftrace_profile *rec = v;
383 char str[KSYM_SYMBOL_LEN];
384 int ret = 0;
385 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
386 static struct trace_seq s;
387 unsigned long long avg;
388 unsigned long long stddev;
389 #endif
390 mutex_lock(&ftrace_profile_lock);
391
392 /* we raced with function_profile_reset() */
393 if (unlikely(rec->counter == 0)) {
394 ret = -EBUSY;
395 goto out;
396 }
397
398 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
399 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
400
401 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
402 seq_printf(m, " ");
403 avg = rec->time;
404 do_div(avg, rec->counter);
405
406 /* Sample standard deviation (s^2) */
407 if (rec->counter <= 1)
408 stddev = 0;
409 else {
410 stddev = rec->time_squared - rec->counter * avg * avg;
411 /*
412 * Divide only 1000 for ns^2 -> us^2 conversion.
413 * trace_print_graph_duration will divide 1000 again.
414 */
415 do_div(stddev, (rec->counter - 1) * 1000);
416 }
417
418 trace_seq_init(&s);
419 trace_print_graph_duration(rec->time, &s);
420 trace_seq_puts(&s, " ");
421 trace_print_graph_duration(avg, &s);
422 trace_seq_puts(&s, " ");
423 trace_print_graph_duration(stddev, &s);
424 trace_print_seq(m, &s);
425 #endif
426 seq_putc(m, '\n');
427 out:
428 mutex_unlock(&ftrace_profile_lock);
429
430 return ret;
431 }
432
433 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
434 {
435 struct ftrace_profile_page *pg;
436
437 pg = stat->pages = stat->start;
438
439 while (pg) {
440 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
441 pg->index = 0;
442 pg = pg->next;
443 }
444
445 memset(stat->hash, 0,
446 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
447 }
448
449 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
450 {
451 struct ftrace_profile_page *pg;
452 int functions;
453 int pages;
454 int i;
455
456 /* If we already allocated, do nothing */
457 if (stat->pages)
458 return 0;
459
460 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
461 if (!stat->pages)
462 return -ENOMEM;
463
464 #ifdef CONFIG_DYNAMIC_FTRACE
465 functions = ftrace_update_tot_cnt;
466 #else
467 /*
468 * We do not know the number of functions that exist because
469 * dynamic tracing is what counts them. With past experience
470 * we have around 20K functions. That should be more than enough.
471 * It is highly unlikely we will execute every function in
472 * the kernel.
473 */
474 functions = 20000;
475 #endif
476
477 pg = stat->start = stat->pages;
478
479 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
480
481 for (i = 0; i < pages; i++) {
482 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
483 if (!pg->next)
484 goto out_free;
485 pg = pg->next;
486 }
487
488 return 0;
489
490 out_free:
491 pg = stat->start;
492 while (pg) {
493 unsigned long tmp = (unsigned long)pg;
494
495 pg = pg->next;
496 free_page(tmp);
497 }
498
499 free_page((unsigned long)stat->pages);
500 stat->pages = NULL;
501 stat->start = NULL;
502
503 return -ENOMEM;
504 }
505
506 static int ftrace_profile_init_cpu(int cpu)
507 {
508 struct ftrace_profile_stat *stat;
509 int size;
510
511 stat = &per_cpu(ftrace_profile_stats, cpu);
512
513 if (stat->hash) {
514 /* If the profile is already created, simply reset it */
515 ftrace_profile_reset(stat);
516 return 0;
517 }
518
519 /*
520 * We are profiling all functions, but usually only a few thousand
521 * functions are hit. We'll make a hash of 1024 items.
522 */
523 size = FTRACE_PROFILE_HASH_SIZE;
524
525 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
526
527 if (!stat->hash)
528 return -ENOMEM;
529
530 if (!ftrace_profile_bits) {
531 size--;
532
533 for (; size; size >>= 1)
534 ftrace_profile_bits++;
535 }
536
537 /* Preallocate the function profiling pages */
538 if (ftrace_profile_pages_init(stat) < 0) {
539 kfree(stat->hash);
540 stat->hash = NULL;
541 return -ENOMEM;
542 }
543
544 return 0;
545 }
546
547 static int ftrace_profile_init(void)
548 {
549 int cpu;
550 int ret = 0;
551
552 for_each_online_cpu(cpu) {
553 ret = ftrace_profile_init_cpu(cpu);
554 if (ret)
555 break;
556 }
557
558 return ret;
559 }
560
561 /* interrupts must be disabled */
562 static struct ftrace_profile *
563 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
564 {
565 struct ftrace_profile *rec;
566 struct hlist_head *hhd;
567 struct hlist_node *n;
568 unsigned long key;
569
570 key = hash_long(ip, ftrace_profile_bits);
571 hhd = &stat->hash[key];
572
573 if (hlist_empty(hhd))
574 return NULL;
575
576 hlist_for_each_entry_rcu(rec, n, hhd, node) {
577 if (rec->ip == ip)
578 return rec;
579 }
580
581 return NULL;
582 }
583
584 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
585 struct ftrace_profile *rec)
586 {
587 unsigned long key;
588
589 key = hash_long(rec->ip, ftrace_profile_bits);
590 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
591 }
592
593 /*
594 * The memory is already allocated, this simply finds a new record to use.
595 */
596 static struct ftrace_profile *
597 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
598 {
599 struct ftrace_profile *rec = NULL;
600
601 /* prevent recursion (from NMIs) */
602 if (atomic_inc_return(&stat->disabled) != 1)
603 goto out;
604
605 /*
606 * Try to find the function again since an NMI
607 * could have added it
608 */
609 rec = ftrace_find_profiled_func(stat, ip);
610 if (rec)
611 goto out;
612
613 if (stat->pages->index == PROFILES_PER_PAGE) {
614 if (!stat->pages->next)
615 goto out;
616 stat->pages = stat->pages->next;
617 }
618
619 rec = &stat->pages->records[stat->pages->index++];
620 rec->ip = ip;
621 ftrace_add_profile(stat, rec);
622
623 out:
624 atomic_dec(&stat->disabled);
625
626 return rec;
627 }
628
629 static void
630 function_profile_call(unsigned long ip, unsigned long parent_ip)
631 {
632 struct ftrace_profile_stat *stat;
633 struct ftrace_profile *rec;
634 unsigned long flags;
635
636 if (!ftrace_profile_enabled)
637 return;
638
639 local_irq_save(flags);
640
641 stat = &__get_cpu_var(ftrace_profile_stats);
642 if (!stat->hash || !ftrace_profile_enabled)
643 goto out;
644
645 rec = ftrace_find_profiled_func(stat, ip);
646 if (!rec) {
647 rec = ftrace_profile_alloc(stat, ip);
648 if (!rec)
649 goto out;
650 }
651
652 rec->counter++;
653 out:
654 local_irq_restore(flags);
655 }
656
657 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
658 static int profile_graph_entry(struct ftrace_graph_ent *trace)
659 {
660 function_profile_call(trace->func, 0);
661 return 1;
662 }
663
664 static void profile_graph_return(struct ftrace_graph_ret *trace)
665 {
666 struct ftrace_profile_stat *stat;
667 unsigned long long calltime;
668 struct ftrace_profile *rec;
669 unsigned long flags;
670
671 local_irq_save(flags);
672 stat = &__get_cpu_var(ftrace_profile_stats);
673 if (!stat->hash || !ftrace_profile_enabled)
674 goto out;
675
676 /* If the calltime was zero'd ignore it */
677 if (!trace->calltime)
678 goto out;
679
680 calltime = trace->rettime - trace->calltime;
681
682 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
683 int index;
684
685 index = trace->depth;
686
687 /* Append this call time to the parent time to subtract */
688 if (index)
689 current->ret_stack[index - 1].subtime += calltime;
690
691 if (current->ret_stack[index].subtime < calltime)
692 calltime -= current->ret_stack[index].subtime;
693 else
694 calltime = 0;
695 }
696
697 rec = ftrace_find_profiled_func(stat, trace->func);
698 if (rec) {
699 rec->time += calltime;
700 rec->time_squared += calltime * calltime;
701 }
702
703 out:
704 local_irq_restore(flags);
705 }
706
707 static int register_ftrace_profiler(void)
708 {
709 return register_ftrace_graph(&profile_graph_return,
710 &profile_graph_entry);
711 }
712
713 static void unregister_ftrace_profiler(void)
714 {
715 unregister_ftrace_graph();
716 }
717 #else
718 static struct ftrace_ops ftrace_profile_ops __read_mostly =
719 {
720 .func = function_profile_call,
721 };
722
723 static int register_ftrace_profiler(void)
724 {
725 return register_ftrace_function(&ftrace_profile_ops);
726 }
727
728 static void unregister_ftrace_profiler(void)
729 {
730 unregister_ftrace_function(&ftrace_profile_ops);
731 }
732 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
733
734 static ssize_t
735 ftrace_profile_write(struct file *filp, const char __user *ubuf,
736 size_t cnt, loff_t *ppos)
737 {
738 unsigned long val;
739 char buf[64]; /* big enough to hold a number */
740 int ret;
741
742 if (cnt >= sizeof(buf))
743 return -EINVAL;
744
745 if (copy_from_user(&buf, ubuf, cnt))
746 return -EFAULT;
747
748 buf[cnt] = 0;
749
750 ret = strict_strtoul(buf, 10, &val);
751 if (ret < 0)
752 return ret;
753
754 val = !!val;
755
756 mutex_lock(&ftrace_profile_lock);
757 if (ftrace_profile_enabled ^ val) {
758 if (val) {
759 ret = ftrace_profile_init();
760 if (ret < 0) {
761 cnt = ret;
762 goto out;
763 }
764
765 ret = register_ftrace_profiler();
766 if (ret < 0) {
767 cnt = ret;
768 goto out;
769 }
770 ftrace_profile_enabled = 1;
771 } else {
772 ftrace_profile_enabled = 0;
773 /*
774 * unregister_ftrace_profiler calls stop_machine
775 * so this acts like an synchronize_sched.
776 */
777 unregister_ftrace_profiler();
778 }
779 }
780 out:
781 mutex_unlock(&ftrace_profile_lock);
782
783 *ppos += cnt;
784
785 return cnt;
786 }
787
788 static ssize_t
789 ftrace_profile_read(struct file *filp, char __user *ubuf,
790 size_t cnt, loff_t *ppos)
791 {
792 char buf[64]; /* big enough to hold a number */
793 int r;
794
795 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
796 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
797 }
798
799 static const struct file_operations ftrace_profile_fops = {
800 .open = tracing_open_generic,
801 .read = ftrace_profile_read,
802 .write = ftrace_profile_write,
803 };
804
805 /* used to initialize the real stat files */
806 static struct tracer_stat function_stats __initdata = {
807 .name = "functions",
808 .stat_start = function_stat_start,
809 .stat_next = function_stat_next,
810 .stat_cmp = function_stat_cmp,
811 .stat_headers = function_stat_headers,
812 .stat_show = function_stat_show
813 };
814
815 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
816 {
817 struct ftrace_profile_stat *stat;
818 struct dentry *entry;
819 char *name;
820 int ret;
821 int cpu;
822
823 for_each_possible_cpu(cpu) {
824 stat = &per_cpu(ftrace_profile_stats, cpu);
825
826 /* allocate enough for function name + cpu number */
827 name = kmalloc(32, GFP_KERNEL);
828 if (!name) {
829 /*
830 * The files created are permanent, if something happens
831 * we still do not free memory.
832 */
833 WARN(1,
834 "Could not allocate stat file for cpu %d\n",
835 cpu);
836 return;
837 }
838 stat->stat = function_stats;
839 snprintf(name, 32, "function%d", cpu);
840 stat->stat.name = name;
841 ret = register_stat_tracer(&stat->stat);
842 if (ret) {
843 WARN(1,
844 "Could not register function stat for cpu %d\n",
845 cpu);
846 kfree(name);
847 return;
848 }
849 }
850
851 entry = debugfs_create_file("function_profile_enabled", 0644,
852 d_tracer, NULL, &ftrace_profile_fops);
853 if (!entry)
854 pr_warning("Could not create debugfs "
855 "'function_profile_enabled' entry\n");
856 }
857
858 #else /* CONFIG_FUNCTION_PROFILER */
859 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
860 {
861 }
862 #endif /* CONFIG_FUNCTION_PROFILER */
863
864 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
865
866 #ifdef CONFIG_DYNAMIC_FTRACE
867
868 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
869 # error Dynamic ftrace depends on MCOUNT_RECORD
870 #endif
871
872 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
873
874 struct ftrace_func_probe {
875 struct hlist_node node;
876 struct ftrace_probe_ops *ops;
877 unsigned long flags;
878 unsigned long ip;
879 void *data;
880 struct rcu_head rcu;
881 };
882
883 enum {
884 FTRACE_ENABLE_CALLS = (1 << 0),
885 FTRACE_DISABLE_CALLS = (1 << 1),
886 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
887 FTRACE_ENABLE_MCOUNT = (1 << 3),
888 FTRACE_DISABLE_MCOUNT = (1 << 4),
889 FTRACE_START_FUNC_RET = (1 << 5),
890 FTRACE_STOP_FUNC_RET = (1 << 6),
891 };
892
893 static int ftrace_filtered;
894
895 static struct dyn_ftrace *ftrace_new_addrs;
896
897 static DEFINE_MUTEX(ftrace_regex_lock);
898
899 struct ftrace_page {
900 struct ftrace_page *next;
901 int index;
902 struct dyn_ftrace records[];
903 };
904
905 #define ENTRIES_PER_PAGE \
906 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
907
908 /* estimate from running different kernels */
909 #define NR_TO_INIT 10000
910
911 static struct ftrace_page *ftrace_pages_start;
912 static struct ftrace_page *ftrace_pages;
913
914 static struct dyn_ftrace *ftrace_free_records;
915
916 /*
917 * This is a double for. Do not use 'break' to break out of the loop,
918 * you must use a goto.
919 */
920 #define do_for_each_ftrace_rec(pg, rec) \
921 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
922 int _____i; \
923 for (_____i = 0; _____i < pg->index; _____i++) { \
924 rec = &pg->records[_____i];
925
926 #define while_for_each_ftrace_rec() \
927 } \
928 }
929
930 static void ftrace_free_rec(struct dyn_ftrace *rec)
931 {
932 rec->freelist = ftrace_free_records;
933 ftrace_free_records = rec;
934 rec->flags |= FTRACE_FL_FREE;
935 }
936
937 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
938 {
939 struct dyn_ftrace *rec;
940
941 /* First check for freed records */
942 if (ftrace_free_records) {
943 rec = ftrace_free_records;
944
945 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
946 FTRACE_WARN_ON_ONCE(1);
947 ftrace_free_records = NULL;
948 return NULL;
949 }
950
951 ftrace_free_records = rec->freelist;
952 memset(rec, 0, sizeof(*rec));
953 return rec;
954 }
955
956 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
957 if (!ftrace_pages->next) {
958 /* allocate another page */
959 ftrace_pages->next =
960 (void *)get_zeroed_page(GFP_KERNEL);
961 if (!ftrace_pages->next)
962 return NULL;
963 }
964 ftrace_pages = ftrace_pages->next;
965 }
966
967 return &ftrace_pages->records[ftrace_pages->index++];
968 }
969
970 static struct dyn_ftrace *
971 ftrace_record_ip(unsigned long ip)
972 {
973 struct dyn_ftrace *rec;
974
975 if (ftrace_disabled)
976 return NULL;
977
978 rec = ftrace_alloc_dyn_node(ip);
979 if (!rec)
980 return NULL;
981
982 rec->ip = ip;
983 rec->newlist = ftrace_new_addrs;
984 ftrace_new_addrs = rec;
985
986 return rec;
987 }
988
989 static void print_ip_ins(const char *fmt, unsigned char *p)
990 {
991 int i;
992
993 printk(KERN_CONT "%s", fmt);
994
995 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
996 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
997 }
998
999 static void ftrace_bug(int failed, unsigned long ip)
1000 {
1001 switch (failed) {
1002 case -EFAULT:
1003 FTRACE_WARN_ON_ONCE(1);
1004 pr_info("ftrace faulted on modifying ");
1005 print_ip_sym(ip);
1006 break;
1007 case -EINVAL:
1008 FTRACE_WARN_ON_ONCE(1);
1009 pr_info("ftrace failed to modify ");
1010 print_ip_sym(ip);
1011 print_ip_ins(" actual: ", (unsigned char *)ip);
1012 printk(KERN_CONT "\n");
1013 break;
1014 case -EPERM:
1015 FTRACE_WARN_ON_ONCE(1);
1016 pr_info("ftrace faulted on writing ");
1017 print_ip_sym(ip);
1018 break;
1019 default:
1020 FTRACE_WARN_ON_ONCE(1);
1021 pr_info("ftrace faulted on unknown error ");
1022 print_ip_sym(ip);
1023 }
1024 }
1025
1026
1027 /* Return 1 if the address range is reserved for ftrace */
1028 int ftrace_text_reserved(void *start, void *end)
1029 {
1030 struct dyn_ftrace *rec;
1031 struct ftrace_page *pg;
1032
1033 do_for_each_ftrace_rec(pg, rec) {
1034 if (rec->ip <= (unsigned long)end &&
1035 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1036 return 1;
1037 } while_for_each_ftrace_rec();
1038 return 0;
1039 }
1040
1041
1042 static int
1043 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1044 {
1045 unsigned long ftrace_addr;
1046 unsigned long flag = 0UL;
1047
1048 ftrace_addr = (unsigned long)FTRACE_ADDR;
1049
1050 /*
1051 * If this record is not to be traced or we want to disable it,
1052 * then disable it.
1053 *
1054 * If we want to enable it and filtering is off, then enable it.
1055 *
1056 * If we want to enable it and filtering is on, enable it only if
1057 * it's filtered
1058 */
1059 if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1060 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1061 flag = FTRACE_FL_ENABLED;
1062 }
1063
1064 /* If the state of this record hasn't changed, then do nothing */
1065 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1066 return 0;
1067
1068 if (flag) {
1069 rec->flags |= FTRACE_FL_ENABLED;
1070 return ftrace_make_call(rec, ftrace_addr);
1071 }
1072
1073 rec->flags &= ~FTRACE_FL_ENABLED;
1074 return ftrace_make_nop(NULL, rec, ftrace_addr);
1075 }
1076
1077 static void ftrace_replace_code(int enable)
1078 {
1079 struct dyn_ftrace *rec;
1080 struct ftrace_page *pg;
1081 int failed;
1082
1083 do_for_each_ftrace_rec(pg, rec) {
1084 /*
1085 * Skip over free records, records that have
1086 * failed and not converted.
1087 */
1088 if (rec->flags & FTRACE_FL_FREE ||
1089 rec->flags & FTRACE_FL_FAILED ||
1090 !(rec->flags & FTRACE_FL_CONVERTED))
1091 continue;
1092
1093 failed = __ftrace_replace_code(rec, enable);
1094 if (failed) {
1095 rec->flags |= FTRACE_FL_FAILED;
1096 ftrace_bug(failed, rec->ip);
1097 /* Stop processing */
1098 return;
1099 }
1100 } while_for_each_ftrace_rec();
1101 }
1102
1103 static int
1104 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1105 {
1106 unsigned long ip;
1107 int ret;
1108
1109 ip = rec->ip;
1110
1111 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1112 if (ret) {
1113 ftrace_bug(ret, ip);
1114 rec->flags |= FTRACE_FL_FAILED;
1115 return 0;
1116 }
1117 return 1;
1118 }
1119
1120 /*
1121 * archs can override this function if they must do something
1122 * before the modifying code is performed.
1123 */
1124 int __weak ftrace_arch_code_modify_prepare(void)
1125 {
1126 return 0;
1127 }
1128
1129 /*
1130 * archs can override this function if they must do something
1131 * after the modifying code is performed.
1132 */
1133 int __weak ftrace_arch_code_modify_post_process(void)
1134 {
1135 return 0;
1136 }
1137
1138 static int __ftrace_modify_code(void *data)
1139 {
1140 int *command = data;
1141
1142 if (*command & FTRACE_ENABLE_CALLS)
1143 ftrace_replace_code(1);
1144 else if (*command & FTRACE_DISABLE_CALLS)
1145 ftrace_replace_code(0);
1146
1147 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1148 ftrace_update_ftrace_func(ftrace_trace_function);
1149
1150 if (*command & FTRACE_START_FUNC_RET)
1151 ftrace_enable_ftrace_graph_caller();
1152 else if (*command & FTRACE_STOP_FUNC_RET)
1153 ftrace_disable_ftrace_graph_caller();
1154
1155 return 0;
1156 }
1157
1158 static void ftrace_run_update_code(int command)
1159 {
1160 int ret;
1161
1162 ret = ftrace_arch_code_modify_prepare();
1163 FTRACE_WARN_ON(ret);
1164 if (ret)
1165 return;
1166
1167 stop_machine(__ftrace_modify_code, &command, NULL);
1168
1169 ret = ftrace_arch_code_modify_post_process();
1170 FTRACE_WARN_ON(ret);
1171 }
1172
1173 static ftrace_func_t saved_ftrace_func;
1174 static int ftrace_start_up;
1175
1176 static void ftrace_startup_enable(int command)
1177 {
1178 if (saved_ftrace_func != ftrace_trace_function) {
1179 saved_ftrace_func = ftrace_trace_function;
1180 command |= FTRACE_UPDATE_TRACE_FUNC;
1181 }
1182
1183 if (!command || !ftrace_enabled)
1184 return;
1185
1186 ftrace_run_update_code(command);
1187 }
1188
1189 static void ftrace_startup(int command)
1190 {
1191 if (unlikely(ftrace_disabled))
1192 return;
1193
1194 ftrace_start_up++;
1195 command |= FTRACE_ENABLE_CALLS;
1196
1197 ftrace_startup_enable(command);
1198 }
1199
1200 static void ftrace_shutdown(int command)
1201 {
1202 if (unlikely(ftrace_disabled))
1203 return;
1204
1205 ftrace_start_up--;
1206 /*
1207 * Just warn in case of unbalance, no need to kill ftrace, it's not
1208 * critical but the ftrace_call callers may be never nopped again after
1209 * further ftrace uses.
1210 */
1211 WARN_ON_ONCE(ftrace_start_up < 0);
1212
1213 if (!ftrace_start_up)
1214 command |= FTRACE_DISABLE_CALLS;
1215
1216 if (saved_ftrace_func != ftrace_trace_function) {
1217 saved_ftrace_func = ftrace_trace_function;
1218 command |= FTRACE_UPDATE_TRACE_FUNC;
1219 }
1220
1221 if (!command || !ftrace_enabled)
1222 return;
1223
1224 ftrace_run_update_code(command);
1225 }
1226
1227 static void ftrace_startup_sysctl(void)
1228 {
1229 int command = FTRACE_ENABLE_MCOUNT;
1230
1231 if (unlikely(ftrace_disabled))
1232 return;
1233
1234 /* Force update next time */
1235 saved_ftrace_func = NULL;
1236 /* ftrace_start_up is true if we want ftrace running */
1237 if (ftrace_start_up)
1238 command |= FTRACE_ENABLE_CALLS;
1239
1240 ftrace_run_update_code(command);
1241 }
1242
1243 static void ftrace_shutdown_sysctl(void)
1244 {
1245 int command = FTRACE_DISABLE_MCOUNT;
1246
1247 if (unlikely(ftrace_disabled))
1248 return;
1249
1250 /* ftrace_start_up is true if ftrace is running */
1251 if (ftrace_start_up)
1252 command |= FTRACE_DISABLE_CALLS;
1253
1254 ftrace_run_update_code(command);
1255 }
1256
1257 static cycle_t ftrace_update_time;
1258 static unsigned long ftrace_update_cnt;
1259 unsigned long ftrace_update_tot_cnt;
1260
1261 static int ftrace_update_code(struct module *mod)
1262 {
1263 struct dyn_ftrace *p;
1264 cycle_t start, stop;
1265
1266 start = ftrace_now(raw_smp_processor_id());
1267 ftrace_update_cnt = 0;
1268
1269 while (ftrace_new_addrs) {
1270
1271 /* If something went wrong, bail without enabling anything */
1272 if (unlikely(ftrace_disabled))
1273 return -1;
1274
1275 p = ftrace_new_addrs;
1276 ftrace_new_addrs = p->newlist;
1277 p->flags = 0L;
1278
1279 /*
1280 * Do the initial record convertion from mcount jump
1281 * to the NOP instructions.
1282 */
1283 if (!ftrace_code_disable(mod, p)) {
1284 ftrace_free_rec(p);
1285 continue;
1286 }
1287
1288 p->flags |= FTRACE_FL_CONVERTED;
1289 ftrace_update_cnt++;
1290
1291 /*
1292 * If the tracing is enabled, go ahead and enable the record.
1293 *
1294 * The reason not to enable the record immediatelly is the
1295 * inherent check of ftrace_make_nop/ftrace_make_call for
1296 * correct previous instructions. Making first the NOP
1297 * conversion puts the module to the correct state, thus
1298 * passing the ftrace_make_call check.
1299 */
1300 if (ftrace_start_up) {
1301 int failed = __ftrace_replace_code(p, 1);
1302 if (failed) {
1303 ftrace_bug(failed, p->ip);
1304 ftrace_free_rec(p);
1305 }
1306 }
1307 }
1308
1309 stop = ftrace_now(raw_smp_processor_id());
1310 ftrace_update_time = stop - start;
1311 ftrace_update_tot_cnt += ftrace_update_cnt;
1312
1313 return 0;
1314 }
1315
1316 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1317 {
1318 struct ftrace_page *pg;
1319 int cnt;
1320 int i;
1321
1322 /* allocate a few pages */
1323 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1324 if (!ftrace_pages_start)
1325 return -1;
1326
1327 /*
1328 * Allocate a few more pages.
1329 *
1330 * TODO: have some parser search vmlinux before
1331 * final linking to find all calls to ftrace.
1332 * Then we can:
1333 * a) know how many pages to allocate.
1334 * and/or
1335 * b) set up the table then.
1336 *
1337 * The dynamic code is still necessary for
1338 * modules.
1339 */
1340
1341 pg = ftrace_pages = ftrace_pages_start;
1342
1343 cnt = num_to_init / ENTRIES_PER_PAGE;
1344 pr_info("ftrace: allocating %ld entries in %d pages\n",
1345 num_to_init, cnt + 1);
1346
1347 for (i = 0; i < cnt; i++) {
1348 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1349
1350 /* If we fail, we'll try later anyway */
1351 if (!pg->next)
1352 break;
1353
1354 pg = pg->next;
1355 }
1356
1357 return 0;
1358 }
1359
1360 enum {
1361 FTRACE_ITER_FILTER = (1 << 0),
1362 FTRACE_ITER_NOTRACE = (1 << 1),
1363 FTRACE_ITER_FAILURES = (1 << 2),
1364 FTRACE_ITER_PRINTALL = (1 << 3),
1365 FTRACE_ITER_HASH = (1 << 4),
1366 };
1367
1368 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1369
1370 struct ftrace_iterator {
1371 struct ftrace_page *pg;
1372 int hidx;
1373 int idx;
1374 unsigned flags;
1375 struct trace_parser parser;
1376 };
1377
1378 static void *
1379 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1380 {
1381 struct ftrace_iterator *iter = m->private;
1382 struct hlist_node *hnd = v;
1383 struct hlist_head *hhd;
1384
1385 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1386
1387 (*pos)++;
1388
1389 retry:
1390 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1391 return NULL;
1392
1393 hhd = &ftrace_func_hash[iter->hidx];
1394
1395 if (hlist_empty(hhd)) {
1396 iter->hidx++;
1397 hnd = NULL;
1398 goto retry;
1399 }
1400
1401 if (!hnd)
1402 hnd = hhd->first;
1403 else {
1404 hnd = hnd->next;
1405 if (!hnd) {
1406 iter->hidx++;
1407 goto retry;
1408 }
1409 }
1410
1411 return hnd;
1412 }
1413
1414 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1415 {
1416 struct ftrace_iterator *iter = m->private;
1417 void *p = NULL;
1418 loff_t l;
1419
1420 if (!(iter->flags & FTRACE_ITER_HASH))
1421 *pos = 0;
1422
1423 iter->flags |= FTRACE_ITER_HASH;
1424
1425 iter->hidx = 0;
1426 for (l = 0; l <= *pos; ) {
1427 p = t_hash_next(m, p, &l);
1428 if (!p)
1429 break;
1430 }
1431 return p;
1432 }
1433
1434 static int t_hash_show(struct seq_file *m, void *v)
1435 {
1436 struct ftrace_func_probe *rec;
1437 struct hlist_node *hnd = v;
1438
1439 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1440
1441 if (rec->ops->print)
1442 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1443
1444 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1445
1446 if (rec->data)
1447 seq_printf(m, ":%p", rec->data);
1448 seq_putc(m, '\n');
1449
1450 return 0;
1451 }
1452
1453 static void *
1454 t_next(struct seq_file *m, void *v, loff_t *pos)
1455 {
1456 struct ftrace_iterator *iter = m->private;
1457 struct dyn_ftrace *rec = NULL;
1458
1459 if (iter->flags & FTRACE_ITER_HASH)
1460 return t_hash_next(m, v, pos);
1461
1462 (*pos)++;
1463
1464 if (iter->flags & FTRACE_ITER_PRINTALL)
1465 return NULL;
1466
1467 retry:
1468 if (iter->idx >= iter->pg->index) {
1469 if (iter->pg->next) {
1470 iter->pg = iter->pg->next;
1471 iter->idx = 0;
1472 goto retry;
1473 }
1474 } else {
1475 rec = &iter->pg->records[iter->idx++];
1476 if ((rec->flags & FTRACE_FL_FREE) ||
1477
1478 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1479 (rec->flags & FTRACE_FL_FAILED)) ||
1480
1481 ((iter->flags & FTRACE_ITER_FAILURES) &&
1482 !(rec->flags & FTRACE_FL_FAILED)) ||
1483
1484 ((iter->flags & FTRACE_ITER_FILTER) &&
1485 !(rec->flags & FTRACE_FL_FILTER)) ||
1486
1487 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1488 !(rec->flags & FTRACE_FL_NOTRACE))) {
1489 rec = NULL;
1490 goto retry;
1491 }
1492 }
1493
1494 return rec;
1495 }
1496
1497 static void *t_start(struct seq_file *m, loff_t *pos)
1498 {
1499 struct ftrace_iterator *iter = m->private;
1500 void *p = NULL;
1501 loff_t l;
1502
1503 mutex_lock(&ftrace_lock);
1504 /*
1505 * For set_ftrace_filter reading, if we have the filter
1506 * off, we can short cut and just print out that all
1507 * functions are enabled.
1508 */
1509 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1510 if (*pos > 0)
1511 return t_hash_start(m, pos);
1512 iter->flags |= FTRACE_ITER_PRINTALL;
1513 /* reset in case of seek/pread */
1514 iter->flags &= ~FTRACE_ITER_HASH;
1515 return iter;
1516 }
1517
1518 if (iter->flags & FTRACE_ITER_HASH)
1519 return t_hash_start(m, pos);
1520
1521 iter->pg = ftrace_pages_start;
1522 iter->idx = 0;
1523 for (l = 0; l <= *pos; ) {
1524 p = t_next(m, p, &l);
1525 if (!p)
1526 break;
1527 }
1528
1529 if (!p && iter->flags & FTRACE_ITER_FILTER)
1530 return t_hash_start(m, pos);
1531
1532 return p;
1533 }
1534
1535 static void t_stop(struct seq_file *m, void *p)
1536 {
1537 mutex_unlock(&ftrace_lock);
1538 }
1539
1540 static int t_show(struct seq_file *m, void *v)
1541 {
1542 struct ftrace_iterator *iter = m->private;
1543 struct dyn_ftrace *rec = v;
1544
1545 if (iter->flags & FTRACE_ITER_HASH)
1546 return t_hash_show(m, v);
1547
1548 if (iter->flags & FTRACE_ITER_PRINTALL) {
1549 seq_printf(m, "#### all functions enabled ####\n");
1550 return 0;
1551 }
1552
1553 if (!rec)
1554 return 0;
1555
1556 seq_printf(m, "%ps\n", (void *)rec->ip);
1557
1558 return 0;
1559 }
1560
1561 static const struct seq_operations show_ftrace_seq_ops = {
1562 .start = t_start,
1563 .next = t_next,
1564 .stop = t_stop,
1565 .show = t_show,
1566 };
1567
1568 static int
1569 ftrace_avail_open(struct inode *inode, struct file *file)
1570 {
1571 struct ftrace_iterator *iter;
1572 int ret;
1573
1574 if (unlikely(ftrace_disabled))
1575 return -ENODEV;
1576
1577 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1578 if (!iter)
1579 return -ENOMEM;
1580
1581 iter->pg = ftrace_pages_start;
1582
1583 ret = seq_open(file, &show_ftrace_seq_ops);
1584 if (!ret) {
1585 struct seq_file *m = file->private_data;
1586
1587 m->private = iter;
1588 } else {
1589 kfree(iter);
1590 }
1591
1592 return ret;
1593 }
1594
1595 static int
1596 ftrace_failures_open(struct inode *inode, struct file *file)
1597 {
1598 int ret;
1599 struct seq_file *m;
1600 struct ftrace_iterator *iter;
1601
1602 ret = ftrace_avail_open(inode, file);
1603 if (!ret) {
1604 m = (struct seq_file *)file->private_data;
1605 iter = (struct ftrace_iterator *)m->private;
1606 iter->flags = FTRACE_ITER_FAILURES;
1607 }
1608
1609 return ret;
1610 }
1611
1612
1613 static void ftrace_filter_reset(int enable)
1614 {
1615 struct ftrace_page *pg;
1616 struct dyn_ftrace *rec;
1617 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1618
1619 mutex_lock(&ftrace_lock);
1620 if (enable)
1621 ftrace_filtered = 0;
1622 do_for_each_ftrace_rec(pg, rec) {
1623 if (rec->flags & FTRACE_FL_FAILED)
1624 continue;
1625 rec->flags &= ~type;
1626 } while_for_each_ftrace_rec();
1627 mutex_unlock(&ftrace_lock);
1628 }
1629
1630 static int
1631 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1632 {
1633 struct ftrace_iterator *iter;
1634 int ret = 0;
1635
1636 if (unlikely(ftrace_disabled))
1637 return -ENODEV;
1638
1639 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1640 if (!iter)
1641 return -ENOMEM;
1642
1643 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1644 kfree(iter);
1645 return -ENOMEM;
1646 }
1647
1648 mutex_lock(&ftrace_regex_lock);
1649 if ((file->f_mode & FMODE_WRITE) &&
1650 (file->f_flags & O_TRUNC))
1651 ftrace_filter_reset(enable);
1652
1653 if (file->f_mode & FMODE_READ) {
1654 iter->pg = ftrace_pages_start;
1655 iter->flags = enable ? FTRACE_ITER_FILTER :
1656 FTRACE_ITER_NOTRACE;
1657
1658 ret = seq_open(file, &show_ftrace_seq_ops);
1659 if (!ret) {
1660 struct seq_file *m = file->private_data;
1661 m->private = iter;
1662 } else {
1663 trace_parser_put(&iter->parser);
1664 kfree(iter);
1665 }
1666 } else
1667 file->private_data = iter;
1668 mutex_unlock(&ftrace_regex_lock);
1669
1670 return ret;
1671 }
1672
1673 static int
1674 ftrace_filter_open(struct inode *inode, struct file *file)
1675 {
1676 return ftrace_regex_open(inode, file, 1);
1677 }
1678
1679 static int
1680 ftrace_notrace_open(struct inode *inode, struct file *file)
1681 {
1682 return ftrace_regex_open(inode, file, 0);
1683 }
1684
1685 static loff_t
1686 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1687 {
1688 loff_t ret;
1689
1690 if (file->f_mode & FMODE_READ)
1691 ret = seq_lseek(file, offset, origin);
1692 else
1693 file->f_pos = ret = 1;
1694
1695 return ret;
1696 }
1697
1698 static int ftrace_match(char *str, char *regex, int len, int type)
1699 {
1700 int matched = 0;
1701 int slen;
1702
1703 switch (type) {
1704 case MATCH_FULL:
1705 if (strcmp(str, regex) == 0)
1706 matched = 1;
1707 break;
1708 case MATCH_FRONT_ONLY:
1709 if (strncmp(str, regex, len) == 0)
1710 matched = 1;
1711 break;
1712 case MATCH_MIDDLE_ONLY:
1713 if (strstr(str, regex))
1714 matched = 1;
1715 break;
1716 case MATCH_END_ONLY:
1717 slen = strlen(str);
1718 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1719 matched = 1;
1720 break;
1721 }
1722
1723 return matched;
1724 }
1725
1726 static int
1727 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1728 {
1729 char str[KSYM_SYMBOL_LEN];
1730
1731 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1732 return ftrace_match(str, regex, len, type);
1733 }
1734
1735 static int ftrace_match_records(char *buff, int len, int enable)
1736 {
1737 unsigned int search_len;
1738 struct ftrace_page *pg;
1739 struct dyn_ftrace *rec;
1740 unsigned long flag;
1741 char *search;
1742 int type;
1743 int not;
1744 int found = 0;
1745
1746 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1747 type = filter_parse_regex(buff, len, &search, &not);
1748
1749 search_len = strlen(search);
1750
1751 mutex_lock(&ftrace_lock);
1752 do_for_each_ftrace_rec(pg, rec) {
1753
1754 if (rec->flags & FTRACE_FL_FAILED)
1755 continue;
1756
1757 if (ftrace_match_record(rec, search, search_len, type)) {
1758 if (not)
1759 rec->flags &= ~flag;
1760 else
1761 rec->flags |= flag;
1762 found = 1;
1763 }
1764 /*
1765 * Only enable filtering if we have a function that
1766 * is filtered on.
1767 */
1768 if (enable && (rec->flags & FTRACE_FL_FILTER))
1769 ftrace_filtered = 1;
1770 } while_for_each_ftrace_rec();
1771 mutex_unlock(&ftrace_lock);
1772
1773 return found;
1774 }
1775
1776 static int
1777 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1778 char *regex, int len, int type)
1779 {
1780 char str[KSYM_SYMBOL_LEN];
1781 char *modname;
1782
1783 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1784
1785 if (!modname || strcmp(modname, mod))
1786 return 0;
1787
1788 /* blank search means to match all funcs in the mod */
1789 if (len)
1790 return ftrace_match(str, regex, len, type);
1791 else
1792 return 1;
1793 }
1794
1795 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1796 {
1797 unsigned search_len = 0;
1798 struct ftrace_page *pg;
1799 struct dyn_ftrace *rec;
1800 int type = MATCH_FULL;
1801 char *search = buff;
1802 unsigned long flag;
1803 int not = 0;
1804 int found = 0;
1805
1806 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1807
1808 /* blank or '*' mean the same */
1809 if (strcmp(buff, "*") == 0)
1810 buff[0] = 0;
1811
1812 /* handle the case of 'dont filter this module' */
1813 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1814 buff[0] = 0;
1815 not = 1;
1816 }
1817
1818 if (strlen(buff)) {
1819 type = filter_parse_regex(buff, strlen(buff), &search, &not);
1820 search_len = strlen(search);
1821 }
1822
1823 mutex_lock(&ftrace_lock);
1824 do_for_each_ftrace_rec(pg, rec) {
1825
1826 if (rec->flags & FTRACE_FL_FAILED)
1827 continue;
1828
1829 if (ftrace_match_module_record(rec, mod,
1830 search, search_len, type)) {
1831 if (not)
1832 rec->flags &= ~flag;
1833 else
1834 rec->flags |= flag;
1835 found = 1;
1836 }
1837 if (enable && (rec->flags & FTRACE_FL_FILTER))
1838 ftrace_filtered = 1;
1839
1840 } while_for_each_ftrace_rec();
1841 mutex_unlock(&ftrace_lock);
1842
1843 return found;
1844 }
1845
1846 /*
1847 * We register the module command as a template to show others how
1848 * to register the a command as well.
1849 */
1850
1851 static int
1852 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1853 {
1854 char *mod;
1855
1856 /*
1857 * cmd == 'mod' because we only registered this func
1858 * for the 'mod' ftrace_func_command.
1859 * But if you register one func with multiple commands,
1860 * you can tell which command was used by the cmd
1861 * parameter.
1862 */
1863
1864 /* we must have a module name */
1865 if (!param)
1866 return -EINVAL;
1867
1868 mod = strsep(&param, ":");
1869 if (!strlen(mod))
1870 return -EINVAL;
1871
1872 if (ftrace_match_module_records(func, mod, enable))
1873 return 0;
1874 return -EINVAL;
1875 }
1876
1877 static struct ftrace_func_command ftrace_mod_cmd = {
1878 .name = "mod",
1879 .func = ftrace_mod_callback,
1880 };
1881
1882 static int __init ftrace_mod_cmd_init(void)
1883 {
1884 return register_ftrace_command(&ftrace_mod_cmd);
1885 }
1886 device_initcall(ftrace_mod_cmd_init);
1887
1888 static void
1889 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1890 {
1891 struct ftrace_func_probe *entry;
1892 struct hlist_head *hhd;
1893 struct hlist_node *n;
1894 unsigned long key;
1895
1896 key = hash_long(ip, FTRACE_HASH_BITS);
1897
1898 hhd = &ftrace_func_hash[key];
1899
1900 if (hlist_empty(hhd))
1901 return;
1902
1903 /*
1904 * Disable preemption for these calls to prevent a RCU grace
1905 * period. This syncs the hash iteration and freeing of items
1906 * on the hash. rcu_read_lock is too dangerous here.
1907 */
1908 preempt_disable_notrace();
1909 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1910 if (entry->ip == ip)
1911 entry->ops->func(ip, parent_ip, &entry->data);
1912 }
1913 preempt_enable_notrace();
1914 }
1915
1916 static struct ftrace_ops trace_probe_ops __read_mostly =
1917 {
1918 .func = function_trace_probe_call,
1919 };
1920
1921 static int ftrace_probe_registered;
1922
1923 static void __enable_ftrace_function_probe(void)
1924 {
1925 int i;
1926
1927 if (ftrace_probe_registered)
1928 return;
1929
1930 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1931 struct hlist_head *hhd = &ftrace_func_hash[i];
1932 if (hhd->first)
1933 break;
1934 }
1935 /* Nothing registered? */
1936 if (i == FTRACE_FUNC_HASHSIZE)
1937 return;
1938
1939 __register_ftrace_function(&trace_probe_ops);
1940 ftrace_startup(0);
1941 ftrace_probe_registered = 1;
1942 }
1943
1944 static void __disable_ftrace_function_probe(void)
1945 {
1946 int i;
1947
1948 if (!ftrace_probe_registered)
1949 return;
1950
1951 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1952 struct hlist_head *hhd = &ftrace_func_hash[i];
1953 if (hhd->first)
1954 return;
1955 }
1956
1957 /* no more funcs left */
1958 __unregister_ftrace_function(&trace_probe_ops);
1959 ftrace_shutdown(0);
1960 ftrace_probe_registered = 0;
1961 }
1962
1963
1964 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1965 {
1966 struct ftrace_func_probe *entry =
1967 container_of(rhp, struct ftrace_func_probe, rcu);
1968
1969 if (entry->ops->free)
1970 entry->ops->free(&entry->data);
1971 kfree(entry);
1972 }
1973
1974
1975 int
1976 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1977 void *data)
1978 {
1979 struct ftrace_func_probe *entry;
1980 struct ftrace_page *pg;
1981 struct dyn_ftrace *rec;
1982 int type, len, not;
1983 unsigned long key;
1984 int count = 0;
1985 char *search;
1986
1987 type = filter_parse_regex(glob, strlen(glob), &search, &not);
1988 len = strlen(search);
1989
1990 /* we do not support '!' for function probes */
1991 if (WARN_ON(not))
1992 return -EINVAL;
1993
1994 mutex_lock(&ftrace_lock);
1995 do_for_each_ftrace_rec(pg, rec) {
1996
1997 if (rec->flags & FTRACE_FL_FAILED)
1998 continue;
1999
2000 if (!ftrace_match_record(rec, search, len, type))
2001 continue;
2002
2003 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2004 if (!entry) {
2005 /* If we did not process any, then return error */
2006 if (!count)
2007 count = -ENOMEM;
2008 goto out_unlock;
2009 }
2010
2011 count++;
2012
2013 entry->data = data;
2014
2015 /*
2016 * The caller might want to do something special
2017 * for each function we find. We call the callback
2018 * to give the caller an opportunity to do so.
2019 */
2020 if (ops->callback) {
2021 if (ops->callback(rec->ip, &entry->data) < 0) {
2022 /* caller does not like this func */
2023 kfree(entry);
2024 continue;
2025 }
2026 }
2027
2028 entry->ops = ops;
2029 entry->ip = rec->ip;
2030
2031 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2032 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2033
2034 } while_for_each_ftrace_rec();
2035 __enable_ftrace_function_probe();
2036
2037 out_unlock:
2038 mutex_unlock(&ftrace_lock);
2039
2040 return count;
2041 }
2042
2043 enum {
2044 PROBE_TEST_FUNC = 1,
2045 PROBE_TEST_DATA = 2
2046 };
2047
2048 static void
2049 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2050 void *data, int flags)
2051 {
2052 struct ftrace_func_probe *entry;
2053 struct hlist_node *n, *tmp;
2054 char str[KSYM_SYMBOL_LEN];
2055 int type = MATCH_FULL;
2056 int i, len = 0;
2057 char *search;
2058
2059 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2060 glob = NULL;
2061 else if (glob) {
2062 int not;
2063
2064 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2065 len = strlen(search);
2066
2067 /* we do not support '!' for function probes */
2068 if (WARN_ON(not))
2069 return;
2070 }
2071
2072 mutex_lock(&ftrace_lock);
2073 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2074 struct hlist_head *hhd = &ftrace_func_hash[i];
2075
2076 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2077
2078 /* break up if statements for readability */
2079 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2080 continue;
2081
2082 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2083 continue;
2084
2085 /* do this last, since it is the most expensive */
2086 if (glob) {
2087 kallsyms_lookup(entry->ip, NULL, NULL,
2088 NULL, str);
2089 if (!ftrace_match(str, glob, len, type))
2090 continue;
2091 }
2092
2093 hlist_del(&entry->node);
2094 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2095 }
2096 }
2097 __disable_ftrace_function_probe();
2098 mutex_unlock(&ftrace_lock);
2099 }
2100
2101 void
2102 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2103 void *data)
2104 {
2105 __unregister_ftrace_function_probe(glob, ops, data,
2106 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2107 }
2108
2109 void
2110 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2111 {
2112 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2113 }
2114
2115 void unregister_ftrace_function_probe_all(char *glob)
2116 {
2117 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2118 }
2119
2120 static LIST_HEAD(ftrace_commands);
2121 static DEFINE_MUTEX(ftrace_cmd_mutex);
2122
2123 int register_ftrace_command(struct ftrace_func_command *cmd)
2124 {
2125 struct ftrace_func_command *p;
2126 int ret = 0;
2127
2128 mutex_lock(&ftrace_cmd_mutex);
2129 list_for_each_entry(p, &ftrace_commands, list) {
2130 if (strcmp(cmd->name, p->name) == 0) {
2131 ret = -EBUSY;
2132 goto out_unlock;
2133 }
2134 }
2135 list_add(&cmd->list, &ftrace_commands);
2136 out_unlock:
2137 mutex_unlock(&ftrace_cmd_mutex);
2138
2139 return ret;
2140 }
2141
2142 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2143 {
2144 struct ftrace_func_command *p, *n;
2145 int ret = -ENODEV;
2146
2147 mutex_lock(&ftrace_cmd_mutex);
2148 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2149 if (strcmp(cmd->name, p->name) == 0) {
2150 ret = 0;
2151 list_del_init(&p->list);
2152 goto out_unlock;
2153 }
2154 }
2155 out_unlock:
2156 mutex_unlock(&ftrace_cmd_mutex);
2157
2158 return ret;
2159 }
2160
2161 static int ftrace_process_regex(char *buff, int len, int enable)
2162 {
2163 char *func, *command, *next = buff;
2164 struct ftrace_func_command *p;
2165 int ret = -EINVAL;
2166
2167 func = strsep(&next, ":");
2168
2169 if (!next) {
2170 if (ftrace_match_records(func, len, enable))
2171 return 0;
2172 return ret;
2173 }
2174
2175 /* command found */
2176
2177 command = strsep(&next, ":");
2178
2179 mutex_lock(&ftrace_cmd_mutex);
2180 list_for_each_entry(p, &ftrace_commands, list) {
2181 if (strcmp(p->name, command) == 0) {
2182 ret = p->func(func, command, next, enable);
2183 goto out_unlock;
2184 }
2185 }
2186 out_unlock:
2187 mutex_unlock(&ftrace_cmd_mutex);
2188
2189 return ret;
2190 }
2191
2192 static ssize_t
2193 ftrace_regex_write(struct file *file, const char __user *ubuf,
2194 size_t cnt, loff_t *ppos, int enable)
2195 {
2196 struct ftrace_iterator *iter;
2197 struct trace_parser *parser;
2198 ssize_t ret, read;
2199
2200 if (!cnt)
2201 return 0;
2202
2203 mutex_lock(&ftrace_regex_lock);
2204
2205 if (file->f_mode & FMODE_READ) {
2206 struct seq_file *m = file->private_data;
2207 iter = m->private;
2208 } else
2209 iter = file->private_data;
2210
2211 parser = &iter->parser;
2212 read = trace_get_user(parser, ubuf, cnt, ppos);
2213
2214 if (read >= 0 && trace_parser_loaded(parser) &&
2215 !trace_parser_cont(parser)) {
2216 ret = ftrace_process_regex(parser->buffer,
2217 parser->idx, enable);
2218 trace_parser_clear(parser);
2219 if (ret)
2220 goto out_unlock;
2221 }
2222
2223 ret = read;
2224 out_unlock:
2225 mutex_unlock(&ftrace_regex_lock);
2226
2227 return ret;
2228 }
2229
2230 static ssize_t
2231 ftrace_filter_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, 1);
2235 }
2236
2237 static ssize_t
2238 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2239 size_t cnt, loff_t *ppos)
2240 {
2241 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2242 }
2243
2244 static void
2245 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2246 {
2247 if (unlikely(ftrace_disabled))
2248 return;
2249
2250 mutex_lock(&ftrace_regex_lock);
2251 if (reset)
2252 ftrace_filter_reset(enable);
2253 if (buf)
2254 ftrace_match_records(buf, len, enable);
2255 mutex_unlock(&ftrace_regex_lock);
2256 }
2257
2258 /**
2259 * ftrace_set_filter - set a function to filter on in ftrace
2260 * @buf - the string that holds the function filter text.
2261 * @len - the length of the string.
2262 * @reset - non zero to reset all filters before applying this filter.
2263 *
2264 * Filters denote which functions should be enabled when tracing is enabled.
2265 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2266 */
2267 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2268 {
2269 ftrace_set_regex(buf, len, reset, 1);
2270 }
2271
2272 /**
2273 * ftrace_set_notrace - set a function to not trace in ftrace
2274 * @buf - the string that holds the function notrace text.
2275 * @len - the length of the string.
2276 * @reset - non zero to reset all filters before applying this filter.
2277 *
2278 * Notrace Filters denote which functions should not be enabled when tracing
2279 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2280 * for tracing.
2281 */
2282 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2283 {
2284 ftrace_set_regex(buf, len, reset, 0);
2285 }
2286
2287 /*
2288 * command line interface to allow users to set filters on boot up.
2289 */
2290 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2291 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2292 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2293
2294 static int __init set_ftrace_notrace(char *str)
2295 {
2296 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2297 return 1;
2298 }
2299 __setup("ftrace_notrace=", set_ftrace_notrace);
2300
2301 static int __init set_ftrace_filter(char *str)
2302 {
2303 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2304 return 1;
2305 }
2306 __setup("ftrace_filter=", set_ftrace_filter);
2307
2308 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2309 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2310 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
2311
2312 static int __init set_graph_function(char *str)
2313 {
2314 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2315 return 1;
2316 }
2317 __setup("ftrace_graph_filter=", set_graph_function);
2318
2319 static void __init set_ftrace_early_graph(char *buf)
2320 {
2321 int ret;
2322 char *func;
2323
2324 while (buf) {
2325 func = strsep(&buf, ",");
2326 /* we allow only one expression at a time */
2327 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2328 func);
2329 if (ret)
2330 printk(KERN_DEBUG "ftrace: function %s not "
2331 "traceable\n", func);
2332 }
2333 }
2334 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2335
2336 static void __init set_ftrace_early_filter(char *buf, int enable)
2337 {
2338 char *func;
2339
2340 while (buf) {
2341 func = strsep(&buf, ",");
2342 ftrace_set_regex(func, strlen(func), 0, enable);
2343 }
2344 }
2345
2346 static void __init set_ftrace_early_filters(void)
2347 {
2348 if (ftrace_filter_buf[0])
2349 set_ftrace_early_filter(ftrace_filter_buf, 1);
2350 if (ftrace_notrace_buf[0])
2351 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2352 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2353 if (ftrace_graph_buf[0])
2354 set_ftrace_early_graph(ftrace_graph_buf);
2355 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2356 }
2357
2358 static int
2359 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2360 {
2361 struct seq_file *m = (struct seq_file *)file->private_data;
2362 struct ftrace_iterator *iter;
2363 struct trace_parser *parser;
2364
2365 mutex_lock(&ftrace_regex_lock);
2366 if (file->f_mode & FMODE_READ) {
2367 iter = m->private;
2368
2369 seq_release(inode, file);
2370 } else
2371 iter = file->private_data;
2372
2373 parser = &iter->parser;
2374 if (trace_parser_loaded(parser)) {
2375 parser->buffer[parser->idx] = 0;
2376 ftrace_match_records(parser->buffer, parser->idx, enable);
2377 }
2378
2379 mutex_lock(&ftrace_lock);
2380 if (ftrace_start_up && ftrace_enabled)
2381 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2382 mutex_unlock(&ftrace_lock);
2383
2384 trace_parser_put(parser);
2385 kfree(iter);
2386
2387 mutex_unlock(&ftrace_regex_lock);
2388 return 0;
2389 }
2390
2391 static int
2392 ftrace_filter_release(struct inode *inode, struct file *file)
2393 {
2394 return ftrace_regex_release(inode, file, 1);
2395 }
2396
2397 static int
2398 ftrace_notrace_release(struct inode *inode, struct file *file)
2399 {
2400 return ftrace_regex_release(inode, file, 0);
2401 }
2402
2403 static const struct file_operations ftrace_avail_fops = {
2404 .open = ftrace_avail_open,
2405 .read = seq_read,
2406 .llseek = seq_lseek,
2407 .release = seq_release_private,
2408 };
2409
2410 static const struct file_operations ftrace_failures_fops = {
2411 .open = ftrace_failures_open,
2412 .read = seq_read,
2413 .llseek = seq_lseek,
2414 .release = seq_release_private,
2415 };
2416
2417 static const struct file_operations ftrace_filter_fops = {
2418 .open = ftrace_filter_open,
2419 .read = seq_read,
2420 .write = ftrace_filter_write,
2421 .llseek = no_llseek,
2422 .release = ftrace_filter_release,
2423 };
2424
2425 static const struct file_operations ftrace_notrace_fops = {
2426 .open = ftrace_notrace_open,
2427 .read = seq_read,
2428 .write = ftrace_notrace_write,
2429 .llseek = ftrace_regex_lseek,
2430 .release = ftrace_notrace_release,
2431 };
2432
2433 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2434
2435 static DEFINE_MUTEX(graph_lock);
2436
2437 int ftrace_graph_count;
2438 int ftrace_graph_filter_enabled;
2439 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2440
2441 static void *
2442 __g_next(struct seq_file *m, loff_t *pos)
2443 {
2444 if (*pos >= ftrace_graph_count)
2445 return NULL;
2446 return &ftrace_graph_funcs[*pos];
2447 }
2448
2449 static void *
2450 g_next(struct seq_file *m, void *v, loff_t *pos)
2451 {
2452 (*pos)++;
2453 return __g_next(m, pos);
2454 }
2455
2456 static void *g_start(struct seq_file *m, loff_t *pos)
2457 {
2458 mutex_lock(&graph_lock);
2459
2460 /* Nothing, tell g_show to print all functions are enabled */
2461 if (!ftrace_graph_filter_enabled && !*pos)
2462 return (void *)1;
2463
2464 return __g_next(m, pos);
2465 }
2466
2467 static void g_stop(struct seq_file *m, void *p)
2468 {
2469 mutex_unlock(&graph_lock);
2470 }
2471
2472 static int g_show(struct seq_file *m, void *v)
2473 {
2474 unsigned long *ptr = v;
2475
2476 if (!ptr)
2477 return 0;
2478
2479 if (ptr == (unsigned long *)1) {
2480 seq_printf(m, "#### all functions enabled ####\n");
2481 return 0;
2482 }
2483
2484 seq_printf(m, "%ps\n", (void *)*ptr);
2485
2486 return 0;
2487 }
2488
2489 static const struct seq_operations ftrace_graph_seq_ops = {
2490 .start = g_start,
2491 .next = g_next,
2492 .stop = g_stop,
2493 .show = g_show,
2494 };
2495
2496 static int
2497 ftrace_graph_open(struct inode *inode, struct file *file)
2498 {
2499 int ret = 0;
2500
2501 if (unlikely(ftrace_disabled))
2502 return -ENODEV;
2503
2504 mutex_lock(&graph_lock);
2505 if ((file->f_mode & FMODE_WRITE) &&
2506 (file->f_flags & O_TRUNC)) {
2507 ftrace_graph_filter_enabled = 0;
2508 ftrace_graph_count = 0;
2509 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2510 }
2511 mutex_unlock(&graph_lock);
2512
2513 if (file->f_mode & FMODE_READ)
2514 ret = seq_open(file, &ftrace_graph_seq_ops);
2515
2516 return ret;
2517 }
2518
2519 static int
2520 ftrace_graph_release(struct inode *inode, struct file *file)
2521 {
2522 if (file->f_mode & FMODE_READ)
2523 seq_release(inode, file);
2524 return 0;
2525 }
2526
2527 static int
2528 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2529 {
2530 struct dyn_ftrace *rec;
2531 struct ftrace_page *pg;
2532 int search_len;
2533 int fail = 1;
2534 int type, not;
2535 char *search;
2536 bool exists;
2537 int i;
2538
2539 if (ftrace_disabled)
2540 return -ENODEV;
2541
2542 /* decode regex */
2543 type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
2544 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
2545 return -EBUSY;
2546
2547 search_len = strlen(search);
2548
2549 mutex_lock(&ftrace_lock);
2550 do_for_each_ftrace_rec(pg, rec) {
2551
2552 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2553 continue;
2554
2555 if (ftrace_match_record(rec, search, search_len, type)) {
2556 /* if it is in the array */
2557 exists = false;
2558 for (i = 0; i < *idx; i++) {
2559 if (array[i] == rec->ip) {
2560 exists = true;
2561 break;
2562 }
2563 }
2564
2565 if (!not) {
2566 fail = 0;
2567 if (!exists) {
2568 array[(*idx)++] = rec->ip;
2569 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2570 goto out;
2571 }
2572 } else {
2573 if (exists) {
2574 array[i] = array[--(*idx)];
2575 array[*idx] = 0;
2576 fail = 0;
2577 }
2578 }
2579 }
2580 } while_for_each_ftrace_rec();
2581 out:
2582 mutex_unlock(&ftrace_lock);
2583
2584 if (fail)
2585 return -EINVAL;
2586
2587 ftrace_graph_filter_enabled = 1;
2588 return 0;
2589 }
2590
2591 static ssize_t
2592 ftrace_graph_write(struct file *file, const char __user *ubuf,
2593 size_t cnt, loff_t *ppos)
2594 {
2595 struct trace_parser parser;
2596 ssize_t read, ret;
2597
2598 if (!cnt)
2599 return 0;
2600
2601 mutex_lock(&graph_lock);
2602
2603 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2604 ret = -ENOMEM;
2605 goto out_unlock;
2606 }
2607
2608 read = trace_get_user(&parser, ubuf, cnt, ppos);
2609
2610 if (read >= 0 && trace_parser_loaded((&parser))) {
2611 parser.buffer[parser.idx] = 0;
2612
2613 /* we allow only one expression at a time */
2614 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2615 parser.buffer);
2616 if (ret)
2617 goto out_free;
2618 }
2619
2620 ret = read;
2621
2622 out_free:
2623 trace_parser_put(&parser);
2624 out_unlock:
2625 mutex_unlock(&graph_lock);
2626
2627 return ret;
2628 }
2629
2630 static const struct file_operations ftrace_graph_fops = {
2631 .open = ftrace_graph_open,
2632 .read = seq_read,
2633 .write = ftrace_graph_write,
2634 .release = ftrace_graph_release,
2635 };
2636 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2637
2638 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2639 {
2640
2641 trace_create_file("available_filter_functions", 0444,
2642 d_tracer, NULL, &ftrace_avail_fops);
2643
2644 trace_create_file("failures", 0444,
2645 d_tracer, NULL, &ftrace_failures_fops);
2646
2647 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2648 NULL, &ftrace_filter_fops);
2649
2650 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2651 NULL, &ftrace_notrace_fops);
2652
2653 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2654 trace_create_file("set_graph_function", 0444, d_tracer,
2655 NULL,
2656 &ftrace_graph_fops);
2657 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2658
2659 return 0;
2660 }
2661
2662 static int ftrace_process_locs(struct module *mod,
2663 unsigned long *start,
2664 unsigned long *end)
2665 {
2666 unsigned long *p;
2667 unsigned long addr;
2668 unsigned long flags;
2669
2670 mutex_lock(&ftrace_lock);
2671 p = start;
2672 while (p < end) {
2673 addr = ftrace_call_adjust(*p++);
2674 /*
2675 * Some architecture linkers will pad between
2676 * the different mcount_loc sections of different
2677 * object files to satisfy alignments.
2678 * Skip any NULL pointers.
2679 */
2680 if (!addr)
2681 continue;
2682 ftrace_record_ip(addr);
2683 }
2684
2685 /* disable interrupts to prevent kstop machine */
2686 local_irq_save(flags);
2687 ftrace_update_code(mod);
2688 local_irq_restore(flags);
2689 mutex_unlock(&ftrace_lock);
2690
2691 return 0;
2692 }
2693
2694 #ifdef CONFIG_MODULES
2695 void ftrace_release_mod(struct module *mod)
2696 {
2697 struct dyn_ftrace *rec;
2698 struct ftrace_page *pg;
2699
2700 if (ftrace_disabled)
2701 return;
2702
2703 mutex_lock(&ftrace_lock);
2704 do_for_each_ftrace_rec(pg, rec) {
2705 if (within_module_core(rec->ip, mod)) {
2706 /*
2707 * rec->ip is changed in ftrace_free_rec()
2708 * It should not between s and e if record was freed.
2709 */
2710 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2711 ftrace_free_rec(rec);
2712 }
2713 } while_for_each_ftrace_rec();
2714 mutex_unlock(&ftrace_lock);
2715 }
2716
2717 static void ftrace_init_module(struct module *mod,
2718 unsigned long *start, unsigned long *end)
2719 {
2720 if (ftrace_disabled || start == end)
2721 return;
2722 ftrace_process_locs(mod, start, end);
2723 }
2724
2725 static int ftrace_module_notify(struct notifier_block *self,
2726 unsigned long val, void *data)
2727 {
2728 struct module *mod = data;
2729
2730 switch (val) {
2731 case MODULE_STATE_COMING:
2732 ftrace_init_module(mod, mod->ftrace_callsites,
2733 mod->ftrace_callsites +
2734 mod->num_ftrace_callsites);
2735 break;
2736 case MODULE_STATE_GOING:
2737 ftrace_release_mod(mod);
2738 break;
2739 }
2740
2741 return 0;
2742 }
2743 #else
2744 static int ftrace_module_notify(struct notifier_block *self,
2745 unsigned long val, void *data)
2746 {
2747 return 0;
2748 }
2749 #endif /* CONFIG_MODULES */
2750
2751 struct notifier_block ftrace_module_nb = {
2752 .notifier_call = ftrace_module_notify,
2753 .priority = 0,
2754 };
2755
2756 extern unsigned long __start_mcount_loc[];
2757 extern unsigned long __stop_mcount_loc[];
2758
2759 void __init ftrace_init(void)
2760 {
2761 unsigned long count, addr, flags;
2762 int ret;
2763
2764 /* Keep the ftrace pointer to the stub */
2765 addr = (unsigned long)ftrace_stub;
2766
2767 local_irq_save(flags);
2768 ftrace_dyn_arch_init(&addr);
2769 local_irq_restore(flags);
2770
2771 /* ftrace_dyn_arch_init places the return code in addr */
2772 if (addr)
2773 goto failed;
2774
2775 count = __stop_mcount_loc - __start_mcount_loc;
2776
2777 ret = ftrace_dyn_table_alloc(count);
2778 if (ret)
2779 goto failed;
2780
2781 last_ftrace_enabled = ftrace_enabled = 1;
2782
2783 ret = ftrace_process_locs(NULL,
2784 __start_mcount_loc,
2785 __stop_mcount_loc);
2786
2787 ret = register_module_notifier(&ftrace_module_nb);
2788 if (ret)
2789 pr_warning("Failed to register trace ftrace module notifier\n");
2790
2791 set_ftrace_early_filters();
2792
2793 return;
2794 failed:
2795 ftrace_disabled = 1;
2796 }
2797
2798 #else
2799
2800 static int __init ftrace_nodyn_init(void)
2801 {
2802 ftrace_enabled = 1;
2803 return 0;
2804 }
2805 device_initcall(ftrace_nodyn_init);
2806
2807 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2808 static inline void ftrace_startup_enable(int command) { }
2809 /* Keep as macros so we do not need to define the commands */
2810 # define ftrace_startup(command) do { } while (0)
2811 # define ftrace_shutdown(command) do { } while (0)
2812 # define ftrace_startup_sysctl() do { } while (0)
2813 # define ftrace_shutdown_sysctl() do { } while (0)
2814 #endif /* CONFIG_DYNAMIC_FTRACE */
2815
2816 static void clear_ftrace_swapper(void)
2817 {
2818 struct task_struct *p;
2819 int cpu;
2820
2821 get_online_cpus();
2822 for_each_online_cpu(cpu) {
2823 p = idle_task(cpu);
2824 clear_tsk_trace_trace(p);
2825 }
2826 put_online_cpus();
2827 }
2828
2829 static void set_ftrace_swapper(void)
2830 {
2831 struct task_struct *p;
2832 int cpu;
2833
2834 get_online_cpus();
2835 for_each_online_cpu(cpu) {
2836 p = idle_task(cpu);
2837 set_tsk_trace_trace(p);
2838 }
2839 put_online_cpus();
2840 }
2841
2842 static void clear_ftrace_pid(struct pid *pid)
2843 {
2844 struct task_struct *p;
2845
2846 rcu_read_lock();
2847 do_each_pid_task(pid, PIDTYPE_PID, p) {
2848 clear_tsk_trace_trace(p);
2849 } while_each_pid_task(pid, PIDTYPE_PID, p);
2850 rcu_read_unlock();
2851
2852 put_pid(pid);
2853 }
2854
2855 static void set_ftrace_pid(struct pid *pid)
2856 {
2857 struct task_struct *p;
2858
2859 rcu_read_lock();
2860 do_each_pid_task(pid, PIDTYPE_PID, p) {
2861 set_tsk_trace_trace(p);
2862 } while_each_pid_task(pid, PIDTYPE_PID, p);
2863 rcu_read_unlock();
2864 }
2865
2866 static void clear_ftrace_pid_task(struct pid *pid)
2867 {
2868 if (pid == ftrace_swapper_pid)
2869 clear_ftrace_swapper();
2870 else
2871 clear_ftrace_pid(pid);
2872 }
2873
2874 static void set_ftrace_pid_task(struct pid *pid)
2875 {
2876 if (pid == ftrace_swapper_pid)
2877 set_ftrace_swapper();
2878 else
2879 set_ftrace_pid(pid);
2880 }
2881
2882 static int ftrace_pid_add(int p)
2883 {
2884 struct pid *pid;
2885 struct ftrace_pid *fpid;
2886 int ret = -EINVAL;
2887
2888 mutex_lock(&ftrace_lock);
2889
2890 if (!p)
2891 pid = ftrace_swapper_pid;
2892 else
2893 pid = find_get_pid(p);
2894
2895 if (!pid)
2896 goto out;
2897
2898 ret = 0;
2899
2900 list_for_each_entry(fpid, &ftrace_pids, list)
2901 if (fpid->pid == pid)
2902 goto out_put;
2903
2904 ret = -ENOMEM;
2905
2906 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2907 if (!fpid)
2908 goto out_put;
2909
2910 list_add(&fpid->list, &ftrace_pids);
2911 fpid->pid = pid;
2912
2913 set_ftrace_pid_task(pid);
2914
2915 ftrace_update_pid_func();
2916 ftrace_startup_enable(0);
2917
2918 mutex_unlock(&ftrace_lock);
2919 return 0;
2920
2921 out_put:
2922 if (pid != ftrace_swapper_pid)
2923 put_pid(pid);
2924
2925 out:
2926 mutex_unlock(&ftrace_lock);
2927 return ret;
2928 }
2929
2930 static void ftrace_pid_reset(void)
2931 {
2932 struct ftrace_pid *fpid, *safe;
2933
2934 mutex_lock(&ftrace_lock);
2935 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2936 struct pid *pid = fpid->pid;
2937
2938 clear_ftrace_pid_task(pid);
2939
2940 list_del(&fpid->list);
2941 kfree(fpid);
2942 }
2943
2944 ftrace_update_pid_func();
2945 ftrace_startup_enable(0);
2946
2947 mutex_unlock(&ftrace_lock);
2948 }
2949
2950 static void *fpid_start(struct seq_file *m, loff_t *pos)
2951 {
2952 mutex_lock(&ftrace_lock);
2953
2954 if (list_empty(&ftrace_pids) && (!*pos))
2955 return (void *) 1;
2956
2957 return seq_list_start(&ftrace_pids, *pos);
2958 }
2959
2960 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
2961 {
2962 if (v == (void *)1)
2963 return NULL;
2964
2965 return seq_list_next(v, &ftrace_pids, pos);
2966 }
2967
2968 static void fpid_stop(struct seq_file *m, void *p)
2969 {
2970 mutex_unlock(&ftrace_lock);
2971 }
2972
2973 static int fpid_show(struct seq_file *m, void *v)
2974 {
2975 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
2976
2977 if (v == (void *)1) {
2978 seq_printf(m, "no pid\n");
2979 return 0;
2980 }
2981
2982 if (fpid->pid == ftrace_swapper_pid)
2983 seq_printf(m, "swapper tasks\n");
2984 else
2985 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
2986
2987 return 0;
2988 }
2989
2990 static const struct seq_operations ftrace_pid_sops = {
2991 .start = fpid_start,
2992 .next = fpid_next,
2993 .stop = fpid_stop,
2994 .show = fpid_show,
2995 };
2996
2997 static int
2998 ftrace_pid_open(struct inode *inode, struct file *file)
2999 {
3000 int ret = 0;
3001
3002 if ((file->f_mode & FMODE_WRITE) &&
3003 (file->f_flags & O_TRUNC))
3004 ftrace_pid_reset();
3005
3006 if (file->f_mode & FMODE_READ)
3007 ret = seq_open(file, &ftrace_pid_sops);
3008
3009 return ret;
3010 }
3011
3012 static ssize_t
3013 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3014 size_t cnt, loff_t *ppos)
3015 {
3016 char buf[64], *tmp;
3017 long val;
3018 int ret;
3019
3020 if (cnt >= sizeof(buf))
3021 return -EINVAL;
3022
3023 if (copy_from_user(&buf, ubuf, cnt))
3024 return -EFAULT;
3025
3026 buf[cnt] = 0;
3027
3028 /*
3029 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3030 * to clean the filter quietly.
3031 */
3032 tmp = strstrip(buf);
3033 if (strlen(tmp) == 0)
3034 return 1;
3035
3036 ret = strict_strtol(tmp, 10, &val);
3037 if (ret < 0)
3038 return ret;
3039
3040 ret = ftrace_pid_add(val);
3041
3042 return ret ? ret : cnt;
3043 }
3044
3045 static int
3046 ftrace_pid_release(struct inode *inode, struct file *file)
3047 {
3048 if (file->f_mode & FMODE_READ)
3049 seq_release(inode, file);
3050
3051 return 0;
3052 }
3053
3054 static const struct file_operations ftrace_pid_fops = {
3055 .open = ftrace_pid_open,
3056 .write = ftrace_pid_write,
3057 .read = seq_read,
3058 .llseek = seq_lseek,
3059 .release = ftrace_pid_release,
3060 };
3061
3062 static __init int ftrace_init_debugfs(void)
3063 {
3064 struct dentry *d_tracer;
3065
3066 d_tracer = tracing_init_dentry();
3067 if (!d_tracer)
3068 return 0;
3069
3070 ftrace_init_dyn_debugfs(d_tracer);
3071
3072 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3073 NULL, &ftrace_pid_fops);
3074
3075 ftrace_profile_debugfs(d_tracer);
3076
3077 return 0;
3078 }
3079 fs_initcall(ftrace_init_debugfs);
3080
3081 /**
3082 * ftrace_kill - kill ftrace
3083 *
3084 * This function should be used by panic code. It stops ftrace
3085 * but in a not so nice way. If you need to simply kill ftrace
3086 * from a non-atomic section, use ftrace_kill.
3087 */
3088 void ftrace_kill(void)
3089 {
3090 ftrace_disabled = 1;
3091 ftrace_enabled = 0;
3092 clear_ftrace_function();
3093 }
3094
3095 /**
3096 * register_ftrace_function - register a function for profiling
3097 * @ops - ops structure that holds the function for profiling.
3098 *
3099 * Register a function to be called by all functions in the
3100 * kernel.
3101 *
3102 * Note: @ops->func and all the functions it calls must be labeled
3103 * with "notrace", otherwise it will go into a
3104 * recursive loop.
3105 */
3106 int register_ftrace_function(struct ftrace_ops *ops)
3107 {
3108 int ret;
3109
3110 if (unlikely(ftrace_disabled))
3111 return -1;
3112
3113 mutex_lock(&ftrace_lock);
3114
3115 ret = __register_ftrace_function(ops);
3116 ftrace_startup(0);
3117
3118 mutex_unlock(&ftrace_lock);
3119 return ret;
3120 }
3121
3122 /**
3123 * unregister_ftrace_function - unregister a function for profiling.
3124 * @ops - ops structure that holds the function to unregister
3125 *
3126 * Unregister a function that was added to be called by ftrace profiling.
3127 */
3128 int unregister_ftrace_function(struct ftrace_ops *ops)
3129 {
3130 int ret;
3131
3132 mutex_lock(&ftrace_lock);
3133 ret = __unregister_ftrace_function(ops);
3134 ftrace_shutdown(0);
3135 mutex_unlock(&ftrace_lock);
3136
3137 return ret;
3138 }
3139
3140 int
3141 ftrace_enable_sysctl(struct ctl_table *table, int write,
3142 void __user *buffer, size_t *lenp,
3143 loff_t *ppos)
3144 {
3145 int ret;
3146
3147 if (unlikely(ftrace_disabled))
3148 return -ENODEV;
3149
3150 mutex_lock(&ftrace_lock);
3151
3152 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3153
3154 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3155 goto out;
3156
3157 last_ftrace_enabled = !!ftrace_enabled;
3158
3159 if (ftrace_enabled) {
3160
3161 ftrace_startup_sysctl();
3162
3163 /* we are starting ftrace again */
3164 if (ftrace_list != &ftrace_list_end) {
3165 if (ftrace_list->next == &ftrace_list_end)
3166 ftrace_trace_function = ftrace_list->func;
3167 else
3168 ftrace_trace_function = ftrace_list_func;
3169 }
3170
3171 } else {
3172 /* stopping ftrace calls (just send to ftrace_stub) */
3173 ftrace_trace_function = ftrace_stub;
3174
3175 ftrace_shutdown_sysctl();
3176 }
3177
3178 out:
3179 mutex_unlock(&ftrace_lock);
3180 return ret;
3181 }
3182
3183 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3184
3185 static int ftrace_graph_active;
3186 static struct notifier_block ftrace_suspend_notifier;
3187
3188 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3189 {
3190 return 0;
3191 }
3192
3193 /* The callbacks that hook a function */
3194 trace_func_graph_ret_t ftrace_graph_return =
3195 (trace_func_graph_ret_t)ftrace_stub;
3196 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3197
3198 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3199 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3200 {
3201 int i;
3202 int ret = 0;
3203 unsigned long flags;
3204 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3205 struct task_struct *g, *t;
3206
3207 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3208 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3209 * sizeof(struct ftrace_ret_stack),
3210 GFP_KERNEL);
3211 if (!ret_stack_list[i]) {
3212 start = 0;
3213 end = i;
3214 ret = -ENOMEM;
3215 goto free;
3216 }
3217 }
3218
3219 read_lock_irqsave(&tasklist_lock, flags);
3220 do_each_thread(g, t) {
3221 if (start == end) {
3222 ret = -EAGAIN;
3223 goto unlock;
3224 }
3225
3226 if (t->ret_stack == NULL) {
3227 atomic_set(&t->tracing_graph_pause, 0);
3228 atomic_set(&t->trace_overrun, 0);
3229 t->curr_ret_stack = -1;
3230 /* Make sure the tasks see the -1 first: */
3231 smp_wmb();
3232 t->ret_stack = ret_stack_list[start++];
3233 }
3234 } while_each_thread(g, t);
3235
3236 unlock:
3237 read_unlock_irqrestore(&tasklist_lock, flags);
3238 free:
3239 for (i = start; i < end; i++)
3240 kfree(ret_stack_list[i]);
3241 return ret;
3242 }
3243
3244 static void
3245 ftrace_graph_probe_sched_switch(void *ignore,
3246 struct task_struct *prev, struct task_struct *next)
3247 {
3248 unsigned long long timestamp;
3249 int index;
3250
3251 /*
3252 * Does the user want to count the time a function was asleep.
3253 * If so, do not update the time stamps.
3254 */
3255 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3256 return;
3257
3258 timestamp = trace_clock_local();
3259
3260 prev->ftrace_timestamp = timestamp;
3261
3262 /* only process tasks that we timestamped */
3263 if (!next->ftrace_timestamp)
3264 return;
3265
3266 /*
3267 * Update all the counters in next to make up for the
3268 * time next was sleeping.
3269 */
3270 timestamp -= next->ftrace_timestamp;
3271
3272 for (index = next->curr_ret_stack; index >= 0; index--)
3273 next->ret_stack[index].calltime += timestamp;
3274 }
3275
3276 /* Allocate a return stack for each task */
3277 static int start_graph_tracing(void)
3278 {
3279 struct ftrace_ret_stack **ret_stack_list;
3280 int ret, cpu;
3281
3282 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3283 sizeof(struct ftrace_ret_stack *),
3284 GFP_KERNEL);
3285
3286 if (!ret_stack_list)
3287 return -ENOMEM;
3288
3289 /* The cpu_boot init_task->ret_stack will never be freed */
3290 for_each_online_cpu(cpu) {
3291 if (!idle_task(cpu)->ret_stack)
3292 ftrace_graph_init_task(idle_task(cpu));
3293 }
3294
3295 do {
3296 ret = alloc_retstack_tasklist(ret_stack_list);
3297 } while (ret == -EAGAIN);
3298
3299 if (!ret) {
3300 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3301 if (ret)
3302 pr_info("ftrace_graph: Couldn't activate tracepoint"
3303 " probe to kernel_sched_switch\n");
3304 }
3305
3306 kfree(ret_stack_list);
3307 return ret;
3308 }
3309
3310 /*
3311 * Hibernation protection.
3312 * The state of the current task is too much unstable during
3313 * suspend/restore to disk. We want to protect against that.
3314 */
3315 static int
3316 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3317 void *unused)
3318 {
3319 switch (state) {
3320 case PM_HIBERNATION_PREPARE:
3321 pause_graph_tracing();
3322 break;
3323
3324 case PM_POST_HIBERNATION:
3325 unpause_graph_tracing();
3326 break;
3327 }
3328 return NOTIFY_DONE;
3329 }
3330
3331 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3332 trace_func_graph_ent_t entryfunc)
3333 {
3334 int ret = 0;
3335
3336 mutex_lock(&ftrace_lock);
3337
3338 /* we currently allow only one tracer registered at a time */
3339 if (ftrace_graph_active) {
3340 ret = -EBUSY;
3341 goto out;
3342 }
3343
3344 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3345 register_pm_notifier(&ftrace_suspend_notifier);
3346
3347 ftrace_graph_active++;
3348 ret = start_graph_tracing();
3349 if (ret) {
3350 ftrace_graph_active--;
3351 goto out;
3352 }
3353
3354 ftrace_graph_return = retfunc;
3355 ftrace_graph_entry = entryfunc;
3356
3357 ftrace_startup(FTRACE_START_FUNC_RET);
3358
3359 out:
3360 mutex_unlock(&ftrace_lock);
3361 return ret;
3362 }
3363
3364 void unregister_ftrace_graph(void)
3365 {
3366 mutex_lock(&ftrace_lock);
3367
3368 if (unlikely(!ftrace_graph_active))
3369 goto out;
3370
3371 ftrace_graph_active--;
3372 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3373 ftrace_graph_entry = ftrace_graph_entry_stub;
3374 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3375 unregister_pm_notifier(&ftrace_suspend_notifier);
3376 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3377
3378 out:
3379 mutex_unlock(&ftrace_lock);
3380 }
3381
3382 /* Allocate a return stack for newly created task */
3383 void ftrace_graph_init_task(struct task_struct *t)
3384 {
3385 /* Make sure we do not use the parent ret_stack */
3386 t->ret_stack = NULL;
3387 t->curr_ret_stack = -1;
3388
3389 if (ftrace_graph_active) {
3390 struct ftrace_ret_stack *ret_stack;
3391
3392 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3393 * sizeof(struct ftrace_ret_stack),
3394 GFP_KERNEL);
3395 if (!ret_stack)
3396 return;
3397 atomic_set(&t->tracing_graph_pause, 0);
3398 atomic_set(&t->trace_overrun, 0);
3399 t->ftrace_timestamp = 0;
3400 /* make curr_ret_stack visable before we add the ret_stack */
3401 smp_wmb();
3402 t->ret_stack = ret_stack;
3403 }
3404 }
3405
3406 void ftrace_graph_exit_task(struct task_struct *t)
3407 {
3408 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3409
3410 t->ret_stack = NULL;
3411 /* NULL must become visible to IRQs before we free it: */
3412 barrier();
3413
3414 kfree(ret_stack);
3415 }
3416
3417 void ftrace_graph_stop(void)
3418 {
3419 ftrace_stop();
3420 }
3421 #endif
Tomato firmware and modifications.