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ASoC: tegra: s/IS_ERR_OR_NULL/IS_ERR/ for clk_get_sys
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / ftrace.c
blobf3dadae83883e89c7f48439531bfc6ac62c0ea99
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 .llseek = default_llseek,
804 };
805
806 /* used to initialize the real stat files */
807 static struct tracer_stat function_stats __initdata = {
808 .name = "functions",
809 .stat_start = function_stat_start,
810 .stat_next = function_stat_next,
811 .stat_cmp = function_stat_cmp,
812 .stat_headers = function_stat_headers,
813 .stat_show = function_stat_show
814 };
815
816 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
817 {
818 struct ftrace_profile_stat *stat;
819 struct dentry *entry;
820 char *name;
821 int ret;
822 int cpu;
823
824 for_each_possible_cpu(cpu) {
825 stat = &per_cpu(ftrace_profile_stats, cpu);
826
827 /* allocate enough for function name + cpu number */
828 name = kmalloc(32, GFP_KERNEL);
829 if (!name) {
830 /*
831 * The files created are permanent, if something happens
832 * we still do not free memory.
833 */
834 WARN(1,
835 "Could not allocate stat file for cpu %d\n",
836 cpu);
837 return;
838 }
839 stat->stat = function_stats;
840 snprintf(name, 32, "function%d", cpu);
841 stat->stat.name = name;
842 ret = register_stat_tracer(&stat->stat);
843 if (ret) {
844 WARN(1,
845 "Could not register function stat for cpu %d\n",
846 cpu);
847 kfree(name);
848 return;
849 }
850 }
851
852 entry = debugfs_create_file("function_profile_enabled", 0644,
853 d_tracer, NULL, &ftrace_profile_fops);
854 if (!entry)
855 pr_warning("Could not create debugfs "
856 "'function_profile_enabled' entry\n");
857 }
858
859 #else /* CONFIG_FUNCTION_PROFILER */
860 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
861 {
862 }
863 #endif /* CONFIG_FUNCTION_PROFILER */
864
865 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
866
867 #ifdef CONFIG_DYNAMIC_FTRACE
868
869 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
870 # error Dynamic ftrace depends on MCOUNT_RECORD
871 #endif
872
873 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
874
875 struct ftrace_func_probe {
876 struct hlist_node node;
877 struct ftrace_probe_ops *ops;
878 unsigned long flags;
879 unsigned long ip;
880 void *data;
881 struct rcu_head rcu;
882 };
883
884 enum {
885 FTRACE_ENABLE_CALLS = (1 << 0),
886 FTRACE_DISABLE_CALLS = (1 << 1),
887 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
888 FTRACE_START_FUNC_RET = (1 << 3),
889 FTRACE_STOP_FUNC_RET = (1 << 4),
890 };
891
892 static int ftrace_filtered;
893
894 static struct dyn_ftrace *ftrace_new_addrs;
895
896 static DEFINE_MUTEX(ftrace_regex_lock);
897
898 struct ftrace_page {
899 struct ftrace_page *next;
900 int index;
901 struct dyn_ftrace records[];
902 };
903
904 #define ENTRIES_PER_PAGE \
905 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
906
907 /* estimate from running different kernels */
908 #define NR_TO_INIT 10000
909
910 static struct ftrace_page *ftrace_pages_start;
911 static struct ftrace_page *ftrace_pages;
912
913 static struct dyn_ftrace *ftrace_free_records;
914
915 /*
916 * This is a double for. Do not use 'break' to break out of the loop,
917 * you must use a goto.
918 */
919 #define do_for_each_ftrace_rec(pg, rec) \
920 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
921 int _____i; \
922 for (_____i = 0; _____i < pg->index; _____i++) { \
923 rec = &pg->records[_____i];
924
925 #define while_for_each_ftrace_rec() \
926 } \
927 }
928
929 static void ftrace_free_rec(struct dyn_ftrace *rec)
930 {
931 rec->freelist = ftrace_free_records;
932 ftrace_free_records = rec;
933 rec->flags |= FTRACE_FL_FREE;
934 }
935
936 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
937 {
938 struct dyn_ftrace *rec;
939
940 /* First check for freed records */
941 if (ftrace_free_records) {
942 rec = ftrace_free_records;
943
944 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
945 FTRACE_WARN_ON_ONCE(1);
946 ftrace_free_records = NULL;
947 return NULL;
948 }
949
950 ftrace_free_records = rec->freelist;
951 memset(rec, 0, sizeof(*rec));
952 return rec;
953 }
954
955 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
956 if (!ftrace_pages->next) {
957 /* allocate another page */
958 ftrace_pages->next =
959 (void *)get_zeroed_page(GFP_KERNEL);
960 if (!ftrace_pages->next)
961 return NULL;
962 }
963 ftrace_pages = ftrace_pages->next;
964 }
965
966 return &ftrace_pages->records[ftrace_pages->index++];
967 }
968
969 static struct dyn_ftrace *
970 ftrace_record_ip(unsigned long ip)
971 {
972 struct dyn_ftrace *rec;
973
974 if (ftrace_disabled)
975 return NULL;
976
977 rec = ftrace_alloc_dyn_node(ip);
978 if (!rec)
979 return NULL;
980
981 rec->ip = ip;
982 rec->newlist = ftrace_new_addrs;
983 ftrace_new_addrs = rec;
984
985 return rec;
986 }
987
988 static void print_ip_ins(const char *fmt, unsigned char *p)
989 {
990 int i;
991
992 printk(KERN_CONT "%s", fmt);
993
994 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
995 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
996 }
997
998 static void ftrace_bug(int failed, unsigned long ip)
999 {
1000 switch (failed) {
1001 case -EFAULT:
1002 FTRACE_WARN_ON_ONCE(1);
1003 pr_info("ftrace faulted on modifying ");
1004 print_ip_sym(ip);
1005 break;
1006 case -EINVAL:
1007 FTRACE_WARN_ON_ONCE(1);
1008 pr_info("ftrace failed to modify ");
1009 print_ip_sym(ip);
1010 print_ip_ins(" actual: ", (unsigned char *)ip);
1011 printk(KERN_CONT "\n");
1012 break;
1013 case -EPERM:
1014 FTRACE_WARN_ON_ONCE(1);
1015 pr_info("ftrace faulted on writing ");
1016 print_ip_sym(ip);
1017 break;
1018 default:
1019 FTRACE_WARN_ON_ONCE(1);
1020 pr_info("ftrace faulted on unknown error ");
1021 print_ip_sym(ip);
1022 }
1023 }
1024
1025
1026 /* Return 1 if the address range is reserved for ftrace */
1027 int ftrace_text_reserved(void *start, void *end)
1028 {
1029 struct dyn_ftrace *rec;
1030 struct ftrace_page *pg;
1031
1032 do_for_each_ftrace_rec(pg, rec) {
1033 if (rec->ip <= (unsigned long)end &&
1034 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1035 return 1;
1036 } while_for_each_ftrace_rec();
1037 return 0;
1038 }
1039
1040
1041 static int
1042 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1043 {
1044 unsigned long ftrace_addr;
1045 unsigned long flag = 0UL;
1046
1047 ftrace_addr = (unsigned long)FTRACE_ADDR;
1048
1049 /*
1050 * If this record is not to be traced or we want to disable it,
1051 * then disable it.
1052 *
1053 * If we want to enable it and filtering is off, then enable it.
1054 *
1055 * If we want to enable it and filtering is on, enable it only if
1056 * it's filtered
1057 */
1058 if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1059 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1060 flag = FTRACE_FL_ENABLED;
1061 }
1062
1063 /* If the state of this record hasn't changed, then do nothing */
1064 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1065 return 0;
1066
1067 if (flag) {
1068 rec->flags |= FTRACE_FL_ENABLED;
1069 return ftrace_make_call(rec, ftrace_addr);
1070 }
1071
1072 rec->flags &= ~FTRACE_FL_ENABLED;
1073 return ftrace_make_nop(NULL, rec, ftrace_addr);
1074 }
1075
1076 static void ftrace_replace_code(int enable)
1077 {
1078 struct dyn_ftrace *rec;
1079 struct ftrace_page *pg;
1080 int failed;
1081
1082 do_for_each_ftrace_rec(pg, rec) {
1083 /*
1084 * Skip over free records, records that have
1085 * failed and not converted.
1086 */
1087 if (rec->flags & FTRACE_FL_FREE ||
1088 rec->flags & FTRACE_FL_FAILED ||
1089 !(rec->flags & FTRACE_FL_CONVERTED))
1090 continue;
1091
1092 failed = __ftrace_replace_code(rec, enable);
1093 if (failed) {
1094 rec->flags |= FTRACE_FL_FAILED;
1095 ftrace_bug(failed, rec->ip);
1096 /* Stop processing */
1097 return;
1098 }
1099 } while_for_each_ftrace_rec();
1100 }
1101
1102 static int
1103 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1104 {
1105 unsigned long ip;
1106 int ret;
1107
1108 ip = rec->ip;
1109
1110 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1111 if (ret) {
1112 ftrace_bug(ret, ip);
1113 rec->flags |= FTRACE_FL_FAILED;
1114 return 0;
1115 }
1116 return 1;
1117 }
1118
1119 /*
1120 * archs can override this function if they must do something
1121 * before the modifying code is performed.
1122 */
1123 int __weak ftrace_arch_code_modify_prepare(void)
1124 {
1125 return 0;
1126 }
1127
1128 /*
1129 * archs can override this function if they must do something
1130 * after the modifying code is performed.
1131 */
1132 int __weak ftrace_arch_code_modify_post_process(void)
1133 {
1134 return 0;
1135 }
1136
1137 static int __ftrace_modify_code(void *data)
1138 {
1139 int *command = data;
1140
1141 if (*command & FTRACE_ENABLE_CALLS)
1142 ftrace_replace_code(1);
1143 else if (*command & FTRACE_DISABLE_CALLS)
1144 ftrace_replace_code(0);
1145
1146 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1147 ftrace_update_ftrace_func(ftrace_trace_function);
1148
1149 if (*command & FTRACE_START_FUNC_RET)
1150 ftrace_enable_ftrace_graph_caller();
1151 else if (*command & FTRACE_STOP_FUNC_RET)
1152 ftrace_disable_ftrace_graph_caller();
1153
1154 return 0;
1155 }
1156
1157 static void ftrace_run_update_code(int command)
1158 {
1159 int ret;
1160
1161 ret = ftrace_arch_code_modify_prepare();
1162 FTRACE_WARN_ON(ret);
1163 if (ret)
1164 return;
1165
1166 stop_machine(__ftrace_modify_code, &command, NULL);
1167
1168 ret = ftrace_arch_code_modify_post_process();
1169 FTRACE_WARN_ON(ret);
1170 }
1171
1172 static ftrace_func_t saved_ftrace_func;
1173 static int ftrace_start_up;
1174
1175 static void ftrace_startup_enable(int command)
1176 {
1177 if (saved_ftrace_func != ftrace_trace_function) {
1178 saved_ftrace_func = ftrace_trace_function;
1179 command |= FTRACE_UPDATE_TRACE_FUNC;
1180 }
1181
1182 if (!command || !ftrace_enabled)
1183 return;
1184
1185 ftrace_run_update_code(command);
1186 }
1187
1188 static void ftrace_startup(int command)
1189 {
1190 if (unlikely(ftrace_disabled))
1191 return;
1192
1193 ftrace_start_up++;
1194 command |= FTRACE_ENABLE_CALLS;
1195
1196 ftrace_startup_enable(command);
1197 }
1198
1199 static void ftrace_shutdown(int command)
1200 {
1201 if (unlikely(ftrace_disabled))
1202 return;
1203
1204 ftrace_start_up--;
1205 /*
1206 * Just warn in case of unbalance, no need to kill ftrace, it's not
1207 * critical but the ftrace_call callers may be never nopped again after
1208 * further ftrace uses.
1209 */
1210 WARN_ON_ONCE(ftrace_start_up < 0);
1211
1212 if (!ftrace_start_up)
1213 command |= FTRACE_DISABLE_CALLS;
1214
1215 if (saved_ftrace_func != ftrace_trace_function) {
1216 saved_ftrace_func = ftrace_trace_function;
1217 command |= FTRACE_UPDATE_TRACE_FUNC;
1218 }
1219
1220 if (!command || !ftrace_enabled)
1221 return;
1222
1223 ftrace_run_update_code(command);
1224 }
1225
1226 static void ftrace_startup_sysctl(void)
1227 {
1228 if (unlikely(ftrace_disabled))
1229 return;
1230
1231 /* Force update next time */
1232 saved_ftrace_func = NULL;
1233 /* ftrace_start_up is true if we want ftrace running */
1234 if (ftrace_start_up)
1235 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1236 }
1237
1238 static void ftrace_shutdown_sysctl(void)
1239 {
1240 if (unlikely(ftrace_disabled))
1241 return;
1242
1243 /* ftrace_start_up is true if ftrace is running */
1244 if (ftrace_start_up)
1245 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1246 }
1247
1248 static cycle_t ftrace_update_time;
1249 static unsigned long ftrace_update_cnt;
1250 unsigned long ftrace_update_tot_cnt;
1251
1252 static int ftrace_update_code(struct module *mod)
1253 {
1254 struct dyn_ftrace *p;
1255 cycle_t start, stop;
1256
1257 start = ftrace_now(raw_smp_processor_id());
1258 ftrace_update_cnt = 0;
1259
1260 while (ftrace_new_addrs) {
1261
1262 /* If something went wrong, bail without enabling anything */
1263 if (unlikely(ftrace_disabled))
1264 return -1;
1265
1266 p = ftrace_new_addrs;
1267 ftrace_new_addrs = p->newlist;
1268 p->flags = 0L;
1269
1270 /*
1271 * Do the initial record convertion from mcount jump
1272 * to the NOP instructions.
1273 */
1274 if (!ftrace_code_disable(mod, p)) {
1275 ftrace_free_rec(p);
1276 continue;
1277 }
1278
1279 p->flags |= FTRACE_FL_CONVERTED;
1280 ftrace_update_cnt++;
1281
1282 /*
1283 * If the tracing is enabled, go ahead and enable the record.
1284 *
1285 * The reason not to enable the record immediatelly is the
1286 * inherent check of ftrace_make_nop/ftrace_make_call for
1287 * correct previous instructions. Making first the NOP
1288 * conversion puts the module to the correct state, thus
1289 * passing the ftrace_make_call check.
1290 */
1291 if (ftrace_start_up) {
1292 int failed = __ftrace_replace_code(p, 1);
1293 if (failed) {
1294 ftrace_bug(failed, p->ip);
1295 ftrace_free_rec(p);
1296 }
1297 }
1298 }
1299
1300 stop = ftrace_now(raw_smp_processor_id());
1301 ftrace_update_time = stop - start;
1302 ftrace_update_tot_cnt += ftrace_update_cnt;
1303
1304 return 0;
1305 }
1306
1307 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1308 {
1309 struct ftrace_page *pg;
1310 int cnt;
1311 int i;
1312
1313 /* allocate a few pages */
1314 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1315 if (!ftrace_pages_start)
1316 return -1;
1317
1318 /*
1319 * Allocate a few more pages.
1320 *
1321 * TODO: have some parser search vmlinux before
1322 * final linking to find all calls to ftrace.
1323 * Then we can:
1324 * a) know how many pages to allocate.
1325 * and/or
1326 * b) set up the table then.
1327 *
1328 * The dynamic code is still necessary for
1329 * modules.
1330 */
1331
1332 pg = ftrace_pages = ftrace_pages_start;
1333
1334 cnt = num_to_init / ENTRIES_PER_PAGE;
1335 pr_info("ftrace: allocating %ld entries in %d pages\n",
1336 num_to_init, cnt + 1);
1337
1338 for (i = 0; i < cnt; i++) {
1339 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1340
1341 /* If we fail, we'll try later anyway */
1342 if (!pg->next)
1343 break;
1344
1345 pg = pg->next;
1346 }
1347
1348 return 0;
1349 }
1350
1351 enum {
1352 FTRACE_ITER_FILTER = (1 << 0),
1353 FTRACE_ITER_NOTRACE = (1 << 1),
1354 FTRACE_ITER_FAILURES = (1 << 2),
1355 FTRACE_ITER_PRINTALL = (1 << 3),
1356 FTRACE_ITER_HASH = (1 << 4),
1357 };
1358
1359 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1360
1361 struct ftrace_iterator {
1362 loff_t pos;
1363 loff_t func_pos;
1364 struct ftrace_page *pg;
1365 struct dyn_ftrace *func;
1366 struct ftrace_func_probe *probe;
1367 struct trace_parser parser;
1368 int hidx;
1369 int idx;
1370 unsigned flags;
1371 };
1372
1373 static void *
1374 t_hash_next(struct seq_file *m, loff_t *pos)
1375 {
1376 struct ftrace_iterator *iter = m->private;
1377 struct hlist_node *hnd = NULL;
1378 struct hlist_head *hhd;
1379
1380 (*pos)++;
1381 iter->pos = *pos;
1382
1383 if (iter->probe)
1384 hnd = &iter->probe->node;
1385 retry:
1386 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1387 return NULL;
1388
1389 hhd = &ftrace_func_hash[iter->hidx];
1390
1391 if (hlist_empty(hhd)) {
1392 iter->hidx++;
1393 hnd = NULL;
1394 goto retry;
1395 }
1396
1397 if (!hnd)
1398 hnd = hhd->first;
1399 else {
1400 hnd = hnd->next;
1401 if (!hnd) {
1402 iter->hidx++;
1403 goto retry;
1404 }
1405 }
1406
1407 if (WARN_ON_ONCE(!hnd))
1408 return NULL;
1409
1410 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1411
1412 return iter;
1413 }
1414
1415 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1416 {
1417 struct ftrace_iterator *iter = m->private;
1418 void *p = NULL;
1419 loff_t l;
1420
1421 if (iter->func_pos > *pos)
1422 return NULL;
1423
1424 iter->hidx = 0;
1425 for (l = 0; l <= (*pos - iter->func_pos); ) {
1426 p = t_hash_next(m, &l);
1427 if (!p)
1428 break;
1429 }
1430 if (!p)
1431 return NULL;
1432
1433 /* Only set this if we have an item */
1434 iter->flags |= FTRACE_ITER_HASH;
1435
1436 return iter;
1437 }
1438
1439 static int
1440 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
1441 {
1442 struct ftrace_func_probe *rec;
1443
1444 rec = iter->probe;
1445 if (WARN_ON_ONCE(!rec))
1446 return -EIO;
1447
1448 if (rec->ops->print)
1449 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1450
1451 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1452
1453 if (rec->data)
1454 seq_printf(m, ":%p", rec->data);
1455 seq_putc(m, '\n');
1456
1457 return 0;
1458 }
1459
1460 static void *
1461 t_next(struct seq_file *m, void *v, loff_t *pos)
1462 {
1463 struct ftrace_iterator *iter = m->private;
1464 struct dyn_ftrace *rec = NULL;
1465
1466 if (iter->flags & FTRACE_ITER_HASH)
1467 return t_hash_next(m, pos);
1468
1469 (*pos)++;
1470 iter->pos = *pos;
1471
1472 if (iter->flags & FTRACE_ITER_PRINTALL)
1473 return t_hash_start(m, pos);
1474
1475 retry:
1476 if (iter->idx >= iter->pg->index) {
1477 if (iter->pg->next) {
1478 iter->pg = iter->pg->next;
1479 iter->idx = 0;
1480 goto retry;
1481 }
1482 } else {
1483 rec = &iter->pg->records[iter->idx++];
1484 if ((rec->flags & FTRACE_FL_FREE) ||
1485
1486 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1487 (rec->flags & FTRACE_FL_FAILED)) ||
1488
1489 ((iter->flags & FTRACE_ITER_FAILURES) &&
1490 !(rec->flags & FTRACE_FL_FAILED)) ||
1491
1492 ((iter->flags & FTRACE_ITER_FILTER) &&
1493 !(rec->flags & FTRACE_FL_FILTER)) ||
1494
1495 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1496 !(rec->flags & FTRACE_FL_NOTRACE))) {
1497 rec = NULL;
1498 goto retry;
1499 }
1500 }
1501
1502 if (!rec)
1503 return t_hash_start(m, pos);
1504
1505 iter->func_pos = *pos;
1506 iter->func = rec;
1507
1508 return iter;
1509 }
1510
1511 static void reset_iter_read(struct ftrace_iterator *iter)
1512 {
1513 iter->pos = 0;
1514 iter->func_pos = 0;
1515 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
1516 }
1517
1518 static void *t_start(struct seq_file *m, loff_t *pos)
1519 {
1520 struct ftrace_iterator *iter = m->private;
1521 void *p = NULL;
1522 loff_t l;
1523
1524 mutex_lock(&ftrace_lock);
1525 /*
1526 * If an lseek was done, then reset and start from beginning.
1527 */
1528 if (*pos < iter->pos)
1529 reset_iter_read(iter);
1530
1531 /*
1532 * For set_ftrace_filter reading, if we have the filter
1533 * off, we can short cut and just print out that all
1534 * functions are enabled.
1535 */
1536 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1537 if (*pos > 0)
1538 return t_hash_start(m, pos);
1539 iter->flags |= FTRACE_ITER_PRINTALL;
1540 /* reset in case of seek/pread */
1541 iter->flags &= ~FTRACE_ITER_HASH;
1542 return iter;
1543 }
1544
1545 if (iter->flags & FTRACE_ITER_HASH)
1546 return t_hash_start(m, pos);
1547
1548 /*
1549 * Unfortunately, we need to restart at ftrace_pages_start
1550 * every time we let go of the ftrace_mutex. This is because
1551 * those pointers can change without the lock.
1552 */
1553 iter->pg = ftrace_pages_start;
1554 iter->idx = 0;
1555 for (l = 0; l <= *pos; ) {
1556 p = t_next(m, p, &l);
1557 if (!p)
1558 break;
1559 }
1560
1561 if (!p) {
1562 if (iter->flags & FTRACE_ITER_FILTER)
1563 return t_hash_start(m, pos);
1564
1565 return NULL;
1566 }
1567
1568 return iter;
1569 }
1570
1571 static void t_stop(struct seq_file *m, void *p)
1572 {
1573 mutex_unlock(&ftrace_lock);
1574 }
1575
1576 static int t_show(struct seq_file *m, void *v)
1577 {
1578 struct ftrace_iterator *iter = m->private;
1579 struct dyn_ftrace *rec;
1580
1581 if (iter->flags & FTRACE_ITER_HASH)
1582 return t_hash_show(m, iter);
1583
1584 if (iter->flags & FTRACE_ITER_PRINTALL) {
1585 seq_printf(m, "#### all functions enabled ####\n");
1586 return 0;
1587 }
1588
1589 rec = iter->func;
1590
1591 if (!rec)
1592 return 0;
1593
1594 seq_printf(m, "%ps\n", (void *)rec->ip);
1595
1596 return 0;
1597 }
1598
1599 static const struct seq_operations show_ftrace_seq_ops = {
1600 .start = t_start,
1601 .next = t_next,
1602 .stop = t_stop,
1603 .show = t_show,
1604 };
1605
1606 static int
1607 ftrace_avail_open(struct inode *inode, struct file *file)
1608 {
1609 struct ftrace_iterator *iter;
1610 int ret;
1611
1612 if (unlikely(ftrace_disabled))
1613 return -ENODEV;
1614
1615 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1616 if (!iter)
1617 return -ENOMEM;
1618
1619 iter->pg = ftrace_pages_start;
1620
1621 ret = seq_open(file, &show_ftrace_seq_ops);
1622 if (!ret) {
1623 struct seq_file *m = file->private_data;
1624
1625 m->private = iter;
1626 } else {
1627 kfree(iter);
1628 }
1629
1630 return ret;
1631 }
1632
1633 static int
1634 ftrace_failures_open(struct inode *inode, struct file *file)
1635 {
1636 int ret;
1637 struct seq_file *m;
1638 struct ftrace_iterator *iter;
1639
1640 ret = ftrace_avail_open(inode, file);
1641 if (!ret) {
1642 m = file->private_data;
1643 iter = m->private;
1644 iter->flags = FTRACE_ITER_FAILURES;
1645 }
1646
1647 return ret;
1648 }
1649
1650
1651 static void ftrace_filter_reset(int enable)
1652 {
1653 struct ftrace_page *pg;
1654 struct dyn_ftrace *rec;
1655 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1656
1657 mutex_lock(&ftrace_lock);
1658 if (enable)
1659 ftrace_filtered = 0;
1660 do_for_each_ftrace_rec(pg, rec) {
1661 if (rec->flags & FTRACE_FL_FAILED)
1662 continue;
1663 rec->flags &= ~type;
1664 } while_for_each_ftrace_rec();
1665 mutex_unlock(&ftrace_lock);
1666 }
1667
1668 static int
1669 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1670 {
1671 struct ftrace_iterator *iter;
1672 int ret = 0;
1673
1674 if (unlikely(ftrace_disabled))
1675 return -ENODEV;
1676
1677 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1678 if (!iter)
1679 return -ENOMEM;
1680
1681 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1682 kfree(iter);
1683 return -ENOMEM;
1684 }
1685
1686 mutex_lock(&ftrace_regex_lock);
1687 if ((file->f_mode & FMODE_WRITE) &&
1688 (file->f_flags & O_TRUNC))
1689 ftrace_filter_reset(enable);
1690
1691 if (file->f_mode & FMODE_READ) {
1692 iter->pg = ftrace_pages_start;
1693 iter->flags = enable ? FTRACE_ITER_FILTER :
1694 FTRACE_ITER_NOTRACE;
1695
1696 ret = seq_open(file, &show_ftrace_seq_ops);
1697 if (!ret) {
1698 struct seq_file *m = file->private_data;
1699 m->private = iter;
1700 } else {
1701 trace_parser_put(&iter->parser);
1702 kfree(iter);
1703 }
1704 } else
1705 file->private_data = iter;
1706 mutex_unlock(&ftrace_regex_lock);
1707
1708 return ret;
1709 }
1710
1711 static int
1712 ftrace_filter_open(struct inode *inode, struct file *file)
1713 {
1714 return ftrace_regex_open(inode, file, 1);
1715 }
1716
1717 static int
1718 ftrace_notrace_open(struct inode *inode, struct file *file)
1719 {
1720 return ftrace_regex_open(inode, file, 0);
1721 }
1722
1723 static loff_t
1724 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1725 {
1726 loff_t ret;
1727
1728 if (file->f_mode & FMODE_READ)
1729 ret = seq_lseek(file, offset, origin);
1730 else
1731 file->f_pos = ret = 1;
1732
1733 return ret;
1734 }
1735
1736 static int ftrace_match(char *str, char *regex, int len, int type)
1737 {
1738 int matched = 0;
1739 int slen;
1740
1741 switch (type) {
1742 case MATCH_FULL:
1743 if (strcmp(str, regex) == 0)
1744 matched = 1;
1745 break;
1746 case MATCH_FRONT_ONLY:
1747 if (strncmp(str, regex, len) == 0)
1748 matched = 1;
1749 break;
1750 case MATCH_MIDDLE_ONLY:
1751 if (strstr(str, regex))
1752 matched = 1;
1753 break;
1754 case MATCH_END_ONLY:
1755 slen = strlen(str);
1756 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1757 matched = 1;
1758 break;
1759 }
1760
1761 return matched;
1762 }
1763
1764 static int
1765 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1766 {
1767 char str[KSYM_SYMBOL_LEN];
1768
1769 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1770 return ftrace_match(str, regex, len, type);
1771 }
1772
1773 static int ftrace_match_records(char *buff, int len, int enable)
1774 {
1775 unsigned int search_len;
1776 struct ftrace_page *pg;
1777 struct dyn_ftrace *rec;
1778 unsigned long flag;
1779 char *search;
1780 int type;
1781 int not;
1782 int found = 0;
1783
1784 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1785 type = filter_parse_regex(buff, len, &search, &not);
1786
1787 search_len = strlen(search);
1788
1789 mutex_lock(&ftrace_lock);
1790 do_for_each_ftrace_rec(pg, rec) {
1791
1792 if (rec->flags & FTRACE_FL_FAILED)
1793 continue;
1794
1795 if (ftrace_match_record(rec, search, search_len, type)) {
1796 if (not)
1797 rec->flags &= ~flag;
1798 else
1799 rec->flags |= flag;
1800 found = 1;
1801 }
1802 /*
1803 * Only enable filtering if we have a function that
1804 * is filtered on.
1805 */
1806 if (enable && (rec->flags & FTRACE_FL_FILTER))
1807 ftrace_filtered = 1;
1808 } while_for_each_ftrace_rec();
1809 mutex_unlock(&ftrace_lock);
1810
1811 return found;
1812 }
1813
1814 static int
1815 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1816 char *regex, int len, int type)
1817 {
1818 char str[KSYM_SYMBOL_LEN];
1819 char *modname;
1820
1821 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1822
1823 if (!modname || strcmp(modname, mod))
1824 return 0;
1825
1826 /* blank search means to match all funcs in the mod */
1827 if (len)
1828 return ftrace_match(str, regex, len, type);
1829 else
1830 return 1;
1831 }
1832
1833 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1834 {
1835 unsigned search_len = 0;
1836 struct ftrace_page *pg;
1837 struct dyn_ftrace *rec;
1838 int type = MATCH_FULL;
1839 char *search = buff;
1840 unsigned long flag;
1841 int not = 0;
1842 int found = 0;
1843
1844 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1845
1846 /* blank or '*' mean the same */
1847 if (strcmp(buff, "*") == 0)
1848 buff[0] = 0;
1849
1850 /* handle the case of 'dont filter this module' */
1851 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1852 buff[0] = 0;
1853 not = 1;
1854 }
1855
1856 if (strlen(buff)) {
1857 type = filter_parse_regex(buff, strlen(buff), &search, &not);
1858 search_len = strlen(search);
1859 }
1860
1861 mutex_lock(&ftrace_lock);
1862 do_for_each_ftrace_rec(pg, rec) {
1863
1864 if (rec->flags & FTRACE_FL_FAILED)
1865 continue;
1866
1867 if (ftrace_match_module_record(rec, mod,
1868 search, search_len, type)) {
1869 if (not)
1870 rec->flags &= ~flag;
1871 else
1872 rec->flags |= flag;
1873 found = 1;
1874 }
1875 if (enable && (rec->flags & FTRACE_FL_FILTER))
1876 ftrace_filtered = 1;
1877
1878 } while_for_each_ftrace_rec();
1879 mutex_unlock(&ftrace_lock);
1880
1881 return found;
1882 }
1883
1884 /*
1885 * We register the module command as a template to show others how
1886 * to register the a command as well.
1887 */
1888
1889 static int
1890 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1891 {
1892 char *mod;
1893
1894 /*
1895 * cmd == 'mod' because we only registered this func
1896 * for the 'mod' ftrace_func_command.
1897 * But if you register one func with multiple commands,
1898 * you can tell which command was used by the cmd
1899 * parameter.
1900 */
1901
1902 /* we must have a module name */
1903 if (!param)
1904 return -EINVAL;
1905
1906 mod = strsep(&param, ":");
1907 if (!strlen(mod))
1908 return -EINVAL;
1909
1910 if (ftrace_match_module_records(func, mod, enable))
1911 return 0;
1912 return -EINVAL;
1913 }
1914
1915 static struct ftrace_func_command ftrace_mod_cmd = {
1916 .name = "mod",
1917 .func = ftrace_mod_callback,
1918 };
1919
1920 static int __init ftrace_mod_cmd_init(void)
1921 {
1922 return register_ftrace_command(&ftrace_mod_cmd);
1923 }
1924 device_initcall(ftrace_mod_cmd_init);
1925
1926 static void
1927 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1928 {
1929 struct ftrace_func_probe *entry;
1930 struct hlist_head *hhd;
1931 struct hlist_node *n;
1932 unsigned long key;
1933
1934 key = hash_long(ip, FTRACE_HASH_BITS);
1935
1936 hhd = &ftrace_func_hash[key];
1937
1938 if (hlist_empty(hhd))
1939 return;
1940
1941 /*
1942 * Disable preemption for these calls to prevent a RCU grace
1943 * period. This syncs the hash iteration and freeing of items
1944 * on the hash. rcu_read_lock is too dangerous here.
1945 */
1946 preempt_disable_notrace();
1947 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1948 if (entry->ip == ip)
1949 entry->ops->func(ip, parent_ip, &entry->data);
1950 }
1951 preempt_enable_notrace();
1952 }
1953
1954 static struct ftrace_ops trace_probe_ops __read_mostly =
1955 {
1956 .func = function_trace_probe_call,
1957 };
1958
1959 static int ftrace_probe_registered;
1960
1961 static void __enable_ftrace_function_probe(void)
1962 {
1963 int i;
1964
1965 if (ftrace_probe_registered)
1966 return;
1967
1968 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1969 struct hlist_head *hhd = &ftrace_func_hash[i];
1970 if (hhd->first)
1971 break;
1972 }
1973 /* Nothing registered? */
1974 if (i == FTRACE_FUNC_HASHSIZE)
1975 return;
1976
1977 __register_ftrace_function(&trace_probe_ops);
1978 ftrace_startup(0);
1979 ftrace_probe_registered = 1;
1980 }
1981
1982 static void __disable_ftrace_function_probe(void)
1983 {
1984 int i;
1985
1986 if (!ftrace_probe_registered)
1987 return;
1988
1989 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1990 struct hlist_head *hhd = &ftrace_func_hash[i];
1991 if (hhd->first)
1992 return;
1993 }
1994
1995 /* no more funcs left */
1996 __unregister_ftrace_function(&trace_probe_ops);
1997 ftrace_shutdown(0);
1998 ftrace_probe_registered = 0;
1999 }
2000
2001
2002 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2003 {
2004 struct ftrace_func_probe *entry =
2005 container_of(rhp, struct ftrace_func_probe, rcu);
2006
2007 if (entry->ops->free)
2008 entry->ops->free(&entry->data);
2009 kfree(entry);
2010 }
2011
2012
2013 int
2014 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2015 void *data)
2016 {
2017 struct ftrace_func_probe *entry;
2018 struct ftrace_page *pg;
2019 struct dyn_ftrace *rec;
2020 int type, len, not;
2021 unsigned long key;
2022 int count = 0;
2023 char *search;
2024
2025 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2026 len = strlen(search);
2027
2028 /* we do not support '!' for function probes */
2029 if (WARN_ON(not))
2030 return -EINVAL;
2031
2032 mutex_lock(&ftrace_lock);
2033 do_for_each_ftrace_rec(pg, rec) {
2034
2035 if (rec->flags & FTRACE_FL_FAILED)
2036 continue;
2037
2038 if (!ftrace_match_record(rec, search, len, type))
2039 continue;
2040
2041 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2042 if (!entry) {
2043 /* If we did not process any, then return error */
2044 if (!count)
2045 count = -ENOMEM;
2046 goto out_unlock;
2047 }
2048
2049 count++;
2050
2051 entry->data = data;
2052
2053 /*
2054 * The caller might want to do something special
2055 * for each function we find. We call the callback
2056 * to give the caller an opportunity to do so.
2057 */
2058 if (ops->callback) {
2059 if (ops->callback(rec->ip, &entry->data) < 0) {
2060 /* caller does not like this func */
2061 kfree(entry);
2062 continue;
2063 }
2064 }
2065
2066 entry->ops = ops;
2067 entry->ip = rec->ip;
2068
2069 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2070 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2071
2072 } while_for_each_ftrace_rec();
2073 __enable_ftrace_function_probe();
2074
2075 out_unlock:
2076 mutex_unlock(&ftrace_lock);
2077
2078 return count;
2079 }
2080
2081 enum {
2082 PROBE_TEST_FUNC = 1,
2083 PROBE_TEST_DATA = 2
2084 };
2085
2086 static void
2087 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2088 void *data, int flags)
2089 {
2090 struct ftrace_func_probe *entry;
2091 struct hlist_node *n, *tmp;
2092 char str[KSYM_SYMBOL_LEN];
2093 int type = MATCH_FULL;
2094 int i, len = 0;
2095 char *search;
2096
2097 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2098 glob = NULL;
2099 else if (glob) {
2100 int not;
2101
2102 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2103 len = strlen(search);
2104
2105 /* we do not support '!' for function probes */
2106 if (WARN_ON(not))
2107 return;
2108 }
2109
2110 mutex_lock(&ftrace_lock);
2111 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2112 struct hlist_head *hhd = &ftrace_func_hash[i];
2113
2114 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2115
2116 /* break up if statements for readability */
2117 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2118 continue;
2119
2120 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2121 continue;
2122
2123 /* do this last, since it is the most expensive */
2124 if (glob) {
2125 kallsyms_lookup(entry->ip, NULL, NULL,
2126 NULL, str);
2127 if (!ftrace_match(str, glob, len, type))
2128 continue;
2129 }
2130
2131 hlist_del(&entry->node);
2132 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2133 }
2134 }
2135 __disable_ftrace_function_probe();
2136 mutex_unlock(&ftrace_lock);
2137 }
2138
2139 void
2140 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2141 void *data)
2142 {
2143 __unregister_ftrace_function_probe(glob, ops, data,
2144 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2145 }
2146
2147 void
2148 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2149 {
2150 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2151 }
2152
2153 void unregister_ftrace_function_probe_all(char *glob)
2154 {
2155 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2156 }
2157
2158 static LIST_HEAD(ftrace_commands);
2159 static DEFINE_MUTEX(ftrace_cmd_mutex);
2160
2161 int register_ftrace_command(struct ftrace_func_command *cmd)
2162 {
2163 struct ftrace_func_command *p;
2164 int ret = 0;
2165
2166 mutex_lock(&ftrace_cmd_mutex);
2167 list_for_each_entry(p, &ftrace_commands, list) {
2168 if (strcmp(cmd->name, p->name) == 0) {
2169 ret = -EBUSY;
2170 goto out_unlock;
2171 }
2172 }
2173 list_add(&cmd->list, &ftrace_commands);
2174 out_unlock:
2175 mutex_unlock(&ftrace_cmd_mutex);
2176
2177 return ret;
2178 }
2179
2180 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2181 {
2182 struct ftrace_func_command *p, *n;
2183 int ret = -ENODEV;
2184
2185 mutex_lock(&ftrace_cmd_mutex);
2186 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2187 if (strcmp(cmd->name, p->name) == 0) {
2188 ret = 0;
2189 list_del_init(&p->list);
2190 goto out_unlock;
2191 }
2192 }
2193 out_unlock:
2194 mutex_unlock(&ftrace_cmd_mutex);
2195
2196 return ret;
2197 }
2198
2199 static int ftrace_process_regex(char *buff, int len, int enable)
2200 {
2201 char *func, *command, *next = buff;
2202 struct ftrace_func_command *p;
2203 int ret = -EINVAL;
2204
2205 func = strsep(&next, ":");
2206
2207 if (!next) {
2208 if (ftrace_match_records(func, len, enable))
2209 return 0;
2210 return ret;
2211 }
2212
2213 /* command found */
2214
2215 command = strsep(&next, ":");
2216
2217 mutex_lock(&ftrace_cmd_mutex);
2218 list_for_each_entry(p, &ftrace_commands, list) {
2219 if (strcmp(p->name, command) == 0) {
2220 ret = p->func(func, command, next, enable);
2221 goto out_unlock;
2222 }
2223 }
2224 out_unlock:
2225 mutex_unlock(&ftrace_cmd_mutex);
2226
2227 return ret;
2228 }
2229
2230 static ssize_t
2231 ftrace_regex_write(struct file *file, const char __user *ubuf,
2232 size_t cnt, loff_t *ppos, int enable)
2233 {
2234 struct ftrace_iterator *iter;
2235 struct trace_parser *parser;
2236 ssize_t ret, read;
2237
2238 if (!cnt)
2239 return 0;
2240
2241 mutex_lock(&ftrace_regex_lock);
2242
2243 if (file->f_mode & FMODE_READ) {
2244 struct seq_file *m = file->private_data;
2245 iter = m->private;
2246 } else
2247 iter = file->private_data;
2248
2249 parser = &iter->parser;
2250 read = trace_get_user(parser, ubuf, cnt, ppos);
2251
2252 if (read >= 0 && trace_parser_loaded(parser) &&
2253 !trace_parser_cont(parser)) {
2254 ret = ftrace_process_regex(parser->buffer,
2255 parser->idx, enable);
2256 trace_parser_clear(parser);
2257 if (ret)
2258 goto out_unlock;
2259 }
2260
2261 ret = read;
2262 out_unlock:
2263 mutex_unlock(&ftrace_regex_lock);
2264
2265 return ret;
2266 }
2267
2268 static ssize_t
2269 ftrace_filter_write(struct file *file, const char __user *ubuf,
2270 size_t cnt, loff_t *ppos)
2271 {
2272 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2273 }
2274
2275 static ssize_t
2276 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2277 size_t cnt, loff_t *ppos)
2278 {
2279 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2280 }
2281
2282 static void
2283 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2284 {
2285 if (unlikely(ftrace_disabled))
2286 return;
2287
2288 mutex_lock(&ftrace_regex_lock);
2289 if (reset)
2290 ftrace_filter_reset(enable);
2291 if (buf)
2292 ftrace_match_records(buf, len, enable);
2293 mutex_unlock(&ftrace_regex_lock);
2294 }
2295
2296 /**
2297 * ftrace_set_filter - set a function to filter on in ftrace
2298 * @buf - the string that holds the function filter text.
2299 * @len - the length of the string.
2300 * @reset - non zero to reset all filters before applying this filter.
2301 *
2302 * Filters denote which functions should be enabled when tracing is enabled.
2303 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2304 */
2305 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2306 {
2307 ftrace_set_regex(buf, len, reset, 1);
2308 }
2309
2310 /**
2311 * ftrace_set_notrace - set a function to not trace in ftrace
2312 * @buf - the string that holds the function notrace text.
2313 * @len - the length of the string.
2314 * @reset - non zero to reset all filters before applying this filter.
2315 *
2316 * Notrace Filters denote which functions should not be enabled when tracing
2317 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2318 * for tracing.
2319 */
2320 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2321 {
2322 ftrace_set_regex(buf, len, reset, 0);
2323 }
2324
2325 /*
2326 * command line interface to allow users to set filters on boot up.
2327 */
2328 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2329 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2330 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2331
2332 static int __init set_ftrace_notrace(char *str)
2333 {
2334 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2335 return 1;
2336 }
2337 __setup("ftrace_notrace=", set_ftrace_notrace);
2338
2339 static int __init set_ftrace_filter(char *str)
2340 {
2341 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2342 return 1;
2343 }
2344 __setup("ftrace_filter=", set_ftrace_filter);
2345
2346 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2347 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2348 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
2349
2350 static int __init set_graph_function(char *str)
2351 {
2352 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2353 return 1;
2354 }
2355 __setup("ftrace_graph_filter=", set_graph_function);
2356
2357 static void __init set_ftrace_early_graph(char *buf)
2358 {
2359 int ret;
2360 char *func;
2361
2362 while (buf) {
2363 func = strsep(&buf, ",");
2364 /* we allow only one expression at a time */
2365 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2366 func);
2367 if (ret)
2368 printk(KERN_DEBUG "ftrace: function %s not "
2369 "traceable\n", func);
2370 }
2371 }
2372 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2373
2374 static void __init set_ftrace_early_filter(char *buf, int enable)
2375 {
2376 char *func;
2377
2378 while (buf) {
2379 func = strsep(&buf, ",");
2380 ftrace_set_regex(func, strlen(func), 0, enable);
2381 }
2382 }
2383
2384 static void __init set_ftrace_early_filters(void)
2385 {
2386 if (ftrace_filter_buf[0])
2387 set_ftrace_early_filter(ftrace_filter_buf, 1);
2388 if (ftrace_notrace_buf[0])
2389 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2390 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2391 if (ftrace_graph_buf[0])
2392 set_ftrace_early_graph(ftrace_graph_buf);
2393 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2394 }
2395
2396 static int
2397 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2398 {
2399 struct seq_file *m = (struct seq_file *)file->private_data;
2400 struct ftrace_iterator *iter;
2401 struct trace_parser *parser;
2402
2403 mutex_lock(&ftrace_regex_lock);
2404 if (file->f_mode & FMODE_READ) {
2405 iter = m->private;
2406
2407 seq_release(inode, file);
2408 } else
2409 iter = file->private_data;
2410
2411 parser = &iter->parser;
2412 if (trace_parser_loaded(parser)) {
2413 parser->buffer[parser->idx] = 0;
2414 ftrace_match_records(parser->buffer, parser->idx, enable);
2415 }
2416
2417 mutex_lock(&ftrace_lock);
2418 if (ftrace_start_up && ftrace_enabled)
2419 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2420 mutex_unlock(&ftrace_lock);
2421
2422 trace_parser_put(parser);
2423 kfree(iter);
2424
2425 mutex_unlock(&ftrace_regex_lock);
2426 return 0;
2427 }
2428
2429 static int
2430 ftrace_filter_release(struct inode *inode, struct file *file)
2431 {
2432 return ftrace_regex_release(inode, file, 1);
2433 }
2434
2435 static int
2436 ftrace_notrace_release(struct inode *inode, struct file *file)
2437 {
2438 return ftrace_regex_release(inode, file, 0);
2439 }
2440
2441 static const struct file_operations ftrace_avail_fops = {
2442 .open = ftrace_avail_open,
2443 .read = seq_read,
2444 .llseek = seq_lseek,
2445 .release = seq_release_private,
2446 };
2447
2448 static const struct file_operations ftrace_failures_fops = {
2449 .open = ftrace_failures_open,
2450 .read = seq_read,
2451 .llseek = seq_lseek,
2452 .release = seq_release_private,
2453 };
2454
2455 static const struct file_operations ftrace_filter_fops = {
2456 .open = ftrace_filter_open,
2457 .read = seq_read,
2458 .write = ftrace_filter_write,
2459 .llseek = ftrace_regex_lseek,
2460 .release = ftrace_filter_release,
2461 };
2462
2463 static const struct file_operations ftrace_notrace_fops = {
2464 .open = ftrace_notrace_open,
2465 .read = seq_read,
2466 .write = ftrace_notrace_write,
2467 .llseek = ftrace_regex_lseek,
2468 .release = ftrace_notrace_release,
2469 };
2470
2471 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2472
2473 static DEFINE_MUTEX(graph_lock);
2474
2475 int ftrace_graph_count;
2476 int ftrace_graph_filter_enabled;
2477 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2478
2479 static void *
2480 __g_next(struct seq_file *m, loff_t *pos)
2481 {
2482 if (*pos >= ftrace_graph_count)
2483 return NULL;
2484 return &ftrace_graph_funcs[*pos];
2485 }
2486
2487 static void *
2488 g_next(struct seq_file *m, void *v, loff_t *pos)
2489 {
2490 (*pos)++;
2491 return __g_next(m, pos);
2492 }
2493
2494 static void *g_start(struct seq_file *m, loff_t *pos)
2495 {
2496 mutex_lock(&graph_lock);
2497
2498 /* Nothing, tell g_show to print all functions are enabled */
2499 if (!ftrace_graph_filter_enabled && !*pos)
2500 return (void *)1;
2501
2502 return __g_next(m, pos);
2503 }
2504
2505 static void g_stop(struct seq_file *m, void *p)
2506 {
2507 mutex_unlock(&graph_lock);
2508 }
2509
2510 static int g_show(struct seq_file *m, void *v)
2511 {
2512 unsigned long *ptr = v;
2513
2514 if (!ptr)
2515 return 0;
2516
2517 if (ptr == (unsigned long *)1) {
2518 seq_printf(m, "#### all functions enabled ####\n");
2519 return 0;
2520 }
2521
2522 seq_printf(m, "%ps\n", (void *)*ptr);
2523
2524 return 0;
2525 }
2526
2527 static const struct seq_operations ftrace_graph_seq_ops = {
2528 .start = g_start,
2529 .next = g_next,
2530 .stop = g_stop,
2531 .show = g_show,
2532 };
2533
2534 static int
2535 ftrace_graph_open(struct inode *inode, struct file *file)
2536 {
2537 int ret = 0;
2538
2539 if (unlikely(ftrace_disabled))
2540 return -ENODEV;
2541
2542 mutex_lock(&graph_lock);
2543 if ((file->f_mode & FMODE_WRITE) &&
2544 (file->f_flags & O_TRUNC)) {
2545 ftrace_graph_filter_enabled = 0;
2546 ftrace_graph_count = 0;
2547 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2548 }
2549 mutex_unlock(&graph_lock);
2550
2551 if (file->f_mode & FMODE_READ)
2552 ret = seq_open(file, &ftrace_graph_seq_ops);
2553
2554 return ret;
2555 }
2556
2557 static int
2558 ftrace_graph_release(struct inode *inode, struct file *file)
2559 {
2560 if (file->f_mode & FMODE_READ)
2561 seq_release(inode, file);
2562 return 0;
2563 }
2564
2565 static int
2566 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2567 {
2568 struct dyn_ftrace *rec;
2569 struct ftrace_page *pg;
2570 int search_len;
2571 int fail = 1;
2572 int type, not;
2573 char *search;
2574 bool exists;
2575 int i;
2576
2577 if (ftrace_disabled)
2578 return -ENODEV;
2579
2580 /* decode regex */
2581 type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
2582 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
2583 return -EBUSY;
2584
2585 search_len = strlen(search);
2586
2587 mutex_lock(&ftrace_lock);
2588 do_for_each_ftrace_rec(pg, rec) {
2589
2590 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2591 continue;
2592
2593 if (ftrace_match_record(rec, search, search_len, type)) {
2594 /* if it is in the array */
2595 exists = false;
2596 for (i = 0; i < *idx; i++) {
2597 if (array[i] == rec->ip) {
2598 exists = true;
2599 break;
2600 }
2601 }
2602
2603 if (!not) {
2604 fail = 0;
2605 if (!exists) {
2606 array[(*idx)++] = rec->ip;
2607 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2608 goto out;
2609 }
2610 } else {
2611 if (exists) {
2612 array[i] = array[--(*idx)];
2613 array[*idx] = 0;
2614 fail = 0;
2615 }
2616 }
2617 }
2618 } while_for_each_ftrace_rec();
2619 out:
2620 mutex_unlock(&ftrace_lock);
2621
2622 if (fail)
2623 return -EINVAL;
2624
2625 ftrace_graph_filter_enabled = 1;
2626 return 0;
2627 }
2628
2629 static ssize_t
2630 ftrace_graph_write(struct file *file, const char __user *ubuf,
2631 size_t cnt, loff_t *ppos)
2632 {
2633 struct trace_parser parser;
2634 ssize_t read, ret;
2635
2636 if (!cnt)
2637 return 0;
2638
2639 mutex_lock(&graph_lock);
2640
2641 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2642 ret = -ENOMEM;
2643 goto out_unlock;
2644 }
2645
2646 read = trace_get_user(&parser, ubuf, cnt, ppos);
2647
2648 if (read >= 0 && trace_parser_loaded((&parser))) {
2649 parser.buffer[parser.idx] = 0;
2650
2651 /* we allow only one expression at a time */
2652 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2653 parser.buffer);
2654 if (ret)
2655 goto out_free;
2656 }
2657
2658 ret = read;
2659
2660 out_free:
2661 trace_parser_put(&parser);
2662 out_unlock:
2663 mutex_unlock(&graph_lock);
2664
2665 return ret;
2666 }
2667
2668 static const struct file_operations ftrace_graph_fops = {
2669 .open = ftrace_graph_open,
2670 .read = seq_read,
2671 .write = ftrace_graph_write,
2672 .release = ftrace_graph_release,
2673 .llseek = seq_lseek,
2674 };
2675 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2676
2677 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2678 {
2679
2680 trace_create_file("available_filter_functions", 0444,
2681 d_tracer, NULL, &ftrace_avail_fops);
2682
2683 trace_create_file("failures", 0444,
2684 d_tracer, NULL, &ftrace_failures_fops);
2685
2686 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2687 NULL, &ftrace_filter_fops);
2688
2689 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2690 NULL, &ftrace_notrace_fops);
2691
2692 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2693 trace_create_file("set_graph_function", 0444, d_tracer,
2694 NULL,
2695 &ftrace_graph_fops);
2696 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2697
2698 return 0;
2699 }
2700
2701 static int ftrace_process_locs(struct module *mod,
2702 unsigned long *start,
2703 unsigned long *end)
2704 {
2705 unsigned long *p;
2706 unsigned long addr;
2707 unsigned long flags;
2708
2709 mutex_lock(&ftrace_lock);
2710 p = start;
2711 while (p < end) {
2712 addr = ftrace_call_adjust(*p++);
2713 /*
2714 * Some architecture linkers will pad between
2715 * the different mcount_loc sections of different
2716 * object files to satisfy alignments.
2717 * Skip any NULL pointers.
2718 */
2719 if (!addr)
2720 continue;
2721 ftrace_record_ip(addr);
2722 }
2723
2724 /* disable interrupts to prevent kstop machine */
2725 local_irq_save(flags);
2726 ftrace_update_code(mod);
2727 local_irq_restore(flags);
2728 mutex_unlock(&ftrace_lock);
2729
2730 return 0;
2731 }
2732
2733 #ifdef CONFIG_MODULES
2734 void ftrace_release_mod(struct module *mod)
2735 {
2736 struct dyn_ftrace *rec;
2737 struct ftrace_page *pg;
2738
2739 if (ftrace_disabled)
2740 return;
2741
2742 mutex_lock(&ftrace_lock);
2743 do_for_each_ftrace_rec(pg, rec) {
2744 if (within_module_core(rec->ip, mod)) {
2745 /*
2746 * rec->ip is changed in ftrace_free_rec()
2747 * It should not between s and e if record was freed.
2748 */
2749 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2750 ftrace_free_rec(rec);
2751 }
2752 } while_for_each_ftrace_rec();
2753 mutex_unlock(&ftrace_lock);
2754 }
2755
2756 static void ftrace_init_module(struct module *mod,
2757 unsigned long *start, unsigned long *end)
2758 {
2759 if (ftrace_disabled || start == end)
2760 return;
2761 ftrace_process_locs(mod, start, end);
2762 }
2763
2764 static int ftrace_module_notify(struct notifier_block *self,
2765 unsigned long val, void *data)
2766 {
2767 struct module *mod = data;
2768
2769 switch (val) {
2770 case MODULE_STATE_COMING:
2771 ftrace_init_module(mod, mod->ftrace_callsites,
2772 mod->ftrace_callsites +
2773 mod->num_ftrace_callsites);
2774 break;
2775 case MODULE_STATE_GOING:
2776 ftrace_release_mod(mod);
2777 break;
2778 }
2779
2780 return 0;
2781 }
2782 #else
2783 static int ftrace_module_notify(struct notifier_block *self,
2784 unsigned long val, void *data)
2785 {
2786 return 0;
2787 }
2788 #endif /* CONFIG_MODULES */
2789
2790 struct notifier_block ftrace_module_nb = {
2791 .notifier_call = ftrace_module_notify,
2792 .priority = 0,
2793 };
2794
2795 extern unsigned long __start_mcount_loc[];
2796 extern unsigned long __stop_mcount_loc[];
2797
2798 void __init ftrace_init(void)
2799 {
2800 unsigned long count, addr, flags;
2801 int ret;
2802
2803 /* Keep the ftrace pointer to the stub */
2804 addr = (unsigned long)ftrace_stub;
2805
2806 local_irq_save(flags);
2807 ftrace_dyn_arch_init(&addr);
2808 local_irq_restore(flags);
2809
2810 /* ftrace_dyn_arch_init places the return code in addr */
2811 if (addr)
2812 goto failed;
2813
2814 count = __stop_mcount_loc - __start_mcount_loc;
2815
2816 ret = ftrace_dyn_table_alloc(count);
2817 if (ret)
2818 goto failed;
2819
2820 last_ftrace_enabled = ftrace_enabled = 1;
2821
2822 ret = ftrace_process_locs(NULL,
2823 __start_mcount_loc,
2824 __stop_mcount_loc);
2825
2826 ret = register_module_notifier(&ftrace_module_nb);
2827 if (ret)
2828 pr_warning("Failed to register trace ftrace module notifier\n");
2829
2830 set_ftrace_early_filters();
2831
2832 return;
2833 failed:
2834 ftrace_disabled = 1;
2835 }
2836
2837 #else
2838
2839 static int __init ftrace_nodyn_init(void)
2840 {
2841 ftrace_enabled = 1;
2842 return 0;
2843 }
2844 device_initcall(ftrace_nodyn_init);
2845
2846 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2847 static inline void ftrace_startup_enable(int command) { }
2848 /* Keep as macros so we do not need to define the commands */
2849 # define ftrace_startup(command) do { } while (0)
2850 # define ftrace_shutdown(command) do { } while (0)
2851 # define ftrace_startup_sysctl() do { } while (0)
2852 # define ftrace_shutdown_sysctl() do { } while (0)
2853 #endif /* CONFIG_DYNAMIC_FTRACE */
2854
2855 static void clear_ftrace_swapper(void)
2856 {
2857 struct task_struct *p;
2858 int cpu;
2859
2860 get_online_cpus();
2861 for_each_online_cpu(cpu) {
2862 p = idle_task(cpu);
2863 clear_tsk_trace_trace(p);
2864 }
2865 put_online_cpus();
2866 }
2867
2868 static void set_ftrace_swapper(void)
2869 {
2870 struct task_struct *p;
2871 int cpu;
2872
2873 get_online_cpus();
2874 for_each_online_cpu(cpu) {
2875 p = idle_task(cpu);
2876 set_tsk_trace_trace(p);
2877 }
2878 put_online_cpus();
2879 }
2880
2881 static void clear_ftrace_pid(struct pid *pid)
2882 {
2883 struct task_struct *p;
2884
2885 rcu_read_lock();
2886 do_each_pid_task(pid, PIDTYPE_PID, p) {
2887 clear_tsk_trace_trace(p);
2888 } while_each_pid_task(pid, PIDTYPE_PID, p);
2889 rcu_read_unlock();
2890
2891 put_pid(pid);
2892 }
2893
2894 static void set_ftrace_pid(struct pid *pid)
2895 {
2896 struct task_struct *p;
2897
2898 rcu_read_lock();
2899 do_each_pid_task(pid, PIDTYPE_PID, p) {
2900 set_tsk_trace_trace(p);
2901 } while_each_pid_task(pid, PIDTYPE_PID, p);
2902 rcu_read_unlock();
2903 }
2904
2905 static void clear_ftrace_pid_task(struct pid *pid)
2906 {
2907 if (pid == ftrace_swapper_pid)
2908 clear_ftrace_swapper();
2909 else
2910 clear_ftrace_pid(pid);
2911 }
2912
2913 static void set_ftrace_pid_task(struct pid *pid)
2914 {
2915 if (pid == ftrace_swapper_pid)
2916 set_ftrace_swapper();
2917 else
2918 set_ftrace_pid(pid);
2919 }
2920
2921 static int ftrace_pid_add(int p)
2922 {
2923 struct pid *pid;
2924 struct ftrace_pid *fpid;
2925 int ret = -EINVAL;
2926
2927 mutex_lock(&ftrace_lock);
2928
2929 if (!p)
2930 pid = ftrace_swapper_pid;
2931 else
2932 pid = find_get_pid(p);
2933
2934 if (!pid)
2935 goto out;
2936
2937 ret = 0;
2938
2939 list_for_each_entry(fpid, &ftrace_pids, list)
2940 if (fpid->pid == pid)
2941 goto out_put;
2942
2943 ret = -ENOMEM;
2944
2945 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2946 if (!fpid)
2947 goto out_put;
2948
2949 list_add(&fpid->list, &ftrace_pids);
2950 fpid->pid = pid;
2951
2952 set_ftrace_pid_task(pid);
2953
2954 ftrace_update_pid_func();
2955 ftrace_startup_enable(0);
2956
2957 mutex_unlock(&ftrace_lock);
2958 return 0;
2959
2960 out_put:
2961 if (pid != ftrace_swapper_pid)
2962 put_pid(pid);
2963
2964 out:
2965 mutex_unlock(&ftrace_lock);
2966 return ret;
2967 }
2968
2969 static void ftrace_pid_reset(void)
2970 {
2971 struct ftrace_pid *fpid, *safe;
2972
2973 mutex_lock(&ftrace_lock);
2974 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2975 struct pid *pid = fpid->pid;
2976
2977 clear_ftrace_pid_task(pid);
2978
2979 list_del(&fpid->list);
2980 kfree(fpid);
2981 }
2982
2983 ftrace_update_pid_func();
2984 ftrace_startup_enable(0);
2985
2986 mutex_unlock(&ftrace_lock);
2987 }
2988
2989 static void *fpid_start(struct seq_file *m, loff_t *pos)
2990 {
2991 mutex_lock(&ftrace_lock);
2992
2993 if (list_empty(&ftrace_pids) && (!*pos))
2994 return (void *) 1;
2995
2996 return seq_list_start(&ftrace_pids, *pos);
2997 }
2998
2999 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3000 {
3001 if (v == (void *)1)
3002 return NULL;
3003
3004 return seq_list_next(v, &ftrace_pids, pos);
3005 }
3006
3007 static void fpid_stop(struct seq_file *m, void *p)
3008 {
3009 mutex_unlock(&ftrace_lock);
3010 }
3011
3012 static int fpid_show(struct seq_file *m, void *v)
3013 {
3014 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3015
3016 if (v == (void *)1) {
3017 seq_printf(m, "no pid\n");
3018 return 0;
3019 }
3020
3021 if (fpid->pid == ftrace_swapper_pid)
3022 seq_printf(m, "swapper tasks\n");
3023 else
3024 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3025
3026 return 0;
3027 }
3028
3029 static const struct seq_operations ftrace_pid_sops = {
3030 .start = fpid_start,
3031 .next = fpid_next,
3032 .stop = fpid_stop,
3033 .show = fpid_show,
3034 };
3035
3036 static int
3037 ftrace_pid_open(struct inode *inode, struct file *file)
3038 {
3039 int ret = 0;
3040
3041 if ((file->f_mode & FMODE_WRITE) &&
3042 (file->f_flags & O_TRUNC))
3043 ftrace_pid_reset();
3044
3045 if (file->f_mode & FMODE_READ)
3046 ret = seq_open(file, &ftrace_pid_sops);
3047
3048 return ret;
3049 }
3050
3051 static ssize_t
3052 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3053 size_t cnt, loff_t *ppos)
3054 {
3055 char buf[64], *tmp;
3056 long val;
3057 int ret;
3058
3059 if (cnt >= sizeof(buf))
3060 return -EINVAL;
3061
3062 if (copy_from_user(&buf, ubuf, cnt))
3063 return -EFAULT;
3064
3065 buf[cnt] = 0;
3066
3067 /*
3068 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3069 * to clean the filter quietly.
3070 */
3071 tmp = strstrip(buf);
3072 if (strlen(tmp) == 0)
3073 return 1;
3074
3075 ret = strict_strtol(tmp, 10, &val);
3076 if (ret < 0)
3077 return ret;
3078
3079 ret = ftrace_pid_add(val);
3080
3081 return ret ? ret : cnt;
3082 }
3083
3084 static int
3085 ftrace_pid_release(struct inode *inode, struct file *file)
3086 {
3087 if (file->f_mode & FMODE_READ)
3088 seq_release(inode, file);
3089
3090 return 0;
3091 }
3092
3093 static const struct file_operations ftrace_pid_fops = {
3094 .open = ftrace_pid_open,
3095 .write = ftrace_pid_write,
3096 .read = seq_read,
3097 .llseek = seq_lseek,
3098 .release = ftrace_pid_release,
3099 };
3100
3101 static __init int ftrace_init_debugfs(void)
3102 {
3103 struct dentry *d_tracer;
3104
3105 d_tracer = tracing_init_dentry();
3106 if (!d_tracer)
3107 return 0;
3108
3109 ftrace_init_dyn_debugfs(d_tracer);
3110
3111 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3112 NULL, &ftrace_pid_fops);
3113
3114 ftrace_profile_debugfs(d_tracer);
3115
3116 return 0;
3117 }
3118 fs_initcall(ftrace_init_debugfs);
3119
3120 /**
3121 * ftrace_kill - kill ftrace
3122 *
3123 * This function should be used by panic code. It stops ftrace
3124 * but in a not so nice way. If you need to simply kill ftrace
3125 * from a non-atomic section, use ftrace_kill.
3126 */
3127 void ftrace_kill(void)
3128 {
3129 ftrace_disabled = 1;
3130 ftrace_enabled = 0;
3131 clear_ftrace_function();
3132 }
3133
3134 /**
3135 * register_ftrace_function - register a function for profiling
3136 * @ops - ops structure that holds the function for profiling.
3137 *
3138 * Register a function to be called by all functions in the
3139 * kernel.
3140 *
3141 * Note: @ops->func and all the functions it calls must be labeled
3142 * with "notrace", otherwise it will go into a
3143 * recursive loop.
3144 */
3145 int register_ftrace_function(struct ftrace_ops *ops)
3146 {
3147 int ret;
3148
3149 if (unlikely(ftrace_disabled))
3150 return -1;
3151
3152 mutex_lock(&ftrace_lock);
3153
3154 ret = __register_ftrace_function(ops);
3155 ftrace_startup(0);
3156
3157 mutex_unlock(&ftrace_lock);
3158 return ret;
3159 }
3160
3161 /**
3162 * unregister_ftrace_function - unregister a function for profiling.
3163 * @ops - ops structure that holds the function to unregister
3164 *
3165 * Unregister a function that was added to be called by ftrace profiling.
3166 */
3167 int unregister_ftrace_function(struct ftrace_ops *ops)
3168 {
3169 int ret;
3170
3171 mutex_lock(&ftrace_lock);
3172 ret = __unregister_ftrace_function(ops);
3173 ftrace_shutdown(0);
3174 mutex_unlock(&ftrace_lock);
3175
3176 return ret;
3177 }
3178
3179 int
3180 ftrace_enable_sysctl(struct ctl_table *table, int write,
3181 void __user *buffer, size_t *lenp,
3182 loff_t *ppos)
3183 {
3184 int ret;
3185
3186 if (unlikely(ftrace_disabled))
3187 return -ENODEV;
3188
3189 mutex_lock(&ftrace_lock);
3190
3191 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3192
3193 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3194 goto out;
3195
3196 last_ftrace_enabled = !!ftrace_enabled;
3197
3198 if (ftrace_enabled) {
3199
3200 ftrace_startup_sysctl();
3201
3202 /* we are starting ftrace again */
3203 if (ftrace_list != &ftrace_list_end) {
3204 if (ftrace_list->next == &ftrace_list_end)
3205 ftrace_trace_function = ftrace_list->func;
3206 else
3207 ftrace_trace_function = ftrace_list_func;
3208 }
3209
3210 } else {
3211 /* stopping ftrace calls (just send to ftrace_stub) */
3212 ftrace_trace_function = ftrace_stub;
3213
3214 ftrace_shutdown_sysctl();
3215 }
3216
3217 out:
3218 mutex_unlock(&ftrace_lock);
3219 return ret;
3220 }
3221
3222 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3223
3224 static int ftrace_graph_active;
3225 static struct notifier_block ftrace_suspend_notifier;
3226
3227 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3228 {
3229 return 0;
3230 }
3231
3232 /* The callbacks that hook a function */
3233 trace_func_graph_ret_t ftrace_graph_return =
3234 (trace_func_graph_ret_t)ftrace_stub;
3235 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3236
3237 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3238 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3239 {
3240 int i;
3241 int ret = 0;
3242 unsigned long flags;
3243 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3244 struct task_struct *g, *t;
3245
3246 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3247 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3248 * sizeof(struct ftrace_ret_stack),
3249 GFP_KERNEL);
3250 if (!ret_stack_list[i]) {
3251 start = 0;
3252 end = i;
3253 ret = -ENOMEM;
3254 goto free;
3255 }
3256 }
3257
3258 read_lock_irqsave(&tasklist_lock, flags);
3259 do_each_thread(g, t) {
3260 if (start == end) {
3261 ret = -EAGAIN;
3262 goto unlock;
3263 }
3264
3265 if (t->ret_stack == NULL) {
3266 atomic_set(&t->tracing_graph_pause, 0);
3267 atomic_set(&t->trace_overrun, 0);
3268 t->curr_ret_stack = -1;
3269 /* Make sure the tasks see the -1 first: */
3270 smp_wmb();
3271 t->ret_stack = ret_stack_list[start++];
3272 }
3273 } while_each_thread(g, t);
3274
3275 unlock:
3276 read_unlock_irqrestore(&tasklist_lock, flags);
3277 free:
3278 for (i = start; i < end; i++)
3279 kfree(ret_stack_list[i]);
3280 return ret;
3281 }
3282
3283 static void
3284 ftrace_graph_probe_sched_switch(void *ignore,
3285 struct task_struct *prev, struct task_struct *next)
3286 {
3287 unsigned long long timestamp;
3288 int index;
3289
3290 /*
3291 * Does the user want to count the time a function was asleep.
3292 * If so, do not update the time stamps.
3293 */
3294 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3295 return;
3296
3297 timestamp = trace_clock_local();
3298
3299 prev->ftrace_timestamp = timestamp;
3300
3301 /* only process tasks that we timestamped */
3302 if (!next->ftrace_timestamp)
3303 return;
3304
3305 /*
3306 * Update all the counters in next to make up for the
3307 * time next was sleeping.
3308 */
3309 timestamp -= next->ftrace_timestamp;
3310
3311 for (index = next->curr_ret_stack; index >= 0; index--)
3312 next->ret_stack[index].calltime += timestamp;
3313 }
3314
3315 /* Allocate a return stack for each task */
3316 static int start_graph_tracing(void)
3317 {
3318 struct ftrace_ret_stack **ret_stack_list;
3319 int ret, cpu;
3320
3321 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3322 sizeof(struct ftrace_ret_stack *),
3323 GFP_KERNEL);
3324
3325 if (!ret_stack_list)
3326 return -ENOMEM;
3327
3328 /* The cpu_boot init_task->ret_stack will never be freed */
3329 for_each_online_cpu(cpu) {
3330 if (!idle_task(cpu)->ret_stack)
3331 ftrace_graph_init_task(idle_task(cpu));
3332 }
3333
3334 do {
3335 ret = alloc_retstack_tasklist(ret_stack_list);
3336 } while (ret == -EAGAIN);
3337
3338 if (!ret) {
3339 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3340 if (ret)
3341 pr_info("ftrace_graph: Couldn't activate tracepoint"
3342 " probe to kernel_sched_switch\n");
3343 }
3344
3345 kfree(ret_stack_list);
3346 return ret;
3347 }
3348
3349 /*
3350 * Hibernation protection.
3351 * The state of the current task is too much unstable during
3352 * suspend/restore to disk. We want to protect against that.
3353 */
3354 static int
3355 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3356 void *unused)
3357 {
3358 switch (state) {
3359 case PM_HIBERNATION_PREPARE:
3360 pause_graph_tracing();
3361 break;
3362
3363 case PM_POST_HIBERNATION:
3364 unpause_graph_tracing();
3365 break;
3366 }
3367 return NOTIFY_DONE;
3368 }
3369
3370 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3371 trace_func_graph_ent_t entryfunc)
3372 {
3373 int ret = 0;
3374
3375 mutex_lock(&ftrace_lock);
3376
3377 /* we currently allow only one tracer registered at a time */
3378 if (ftrace_graph_active) {
3379 ret = -EBUSY;
3380 goto out;
3381 }
3382
3383 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3384 register_pm_notifier(&ftrace_suspend_notifier);
3385
3386 ftrace_graph_active++;
3387 ret = start_graph_tracing();
3388 if (ret) {
3389 ftrace_graph_active--;
3390 goto out;
3391 }
3392
3393 ftrace_graph_return = retfunc;
3394 ftrace_graph_entry = entryfunc;
3395
3396 ftrace_startup(FTRACE_START_FUNC_RET);
3397
3398 out:
3399 mutex_unlock(&ftrace_lock);
3400 return ret;
3401 }
3402
3403 void unregister_ftrace_graph(void)
3404 {
3405 mutex_lock(&ftrace_lock);
3406
3407 if (unlikely(!ftrace_graph_active))
3408 goto out;
3409
3410 ftrace_graph_active--;
3411 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3412 ftrace_graph_entry = ftrace_graph_entry_stub;
3413 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3414 unregister_pm_notifier(&ftrace_suspend_notifier);
3415 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3416
3417 out:
3418 mutex_unlock(&ftrace_lock);
3419 }
3420
3421 /* Allocate a return stack for newly created task */
3422 void ftrace_graph_init_task(struct task_struct *t)
3423 {
3424 /* Make sure we do not use the parent ret_stack */
3425 t->ret_stack = NULL;
3426 t->curr_ret_stack = -1;
3427
3428 if (ftrace_graph_active) {
3429 struct ftrace_ret_stack *ret_stack;
3430
3431 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3432 * sizeof(struct ftrace_ret_stack),
3433 GFP_KERNEL);
3434 if (!ret_stack)
3435 return;
3436 atomic_set(&t->tracing_graph_pause, 0);
3437 atomic_set(&t->trace_overrun, 0);
3438 t->ftrace_timestamp = 0;
3439 /* make curr_ret_stack visable before we add the ret_stack */
3440 smp_wmb();
3441 t->ret_stack = ret_stack;
3442 }
3443 }
3444
3445 void ftrace_graph_exit_task(struct task_struct *t)
3446 {
3447 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3448
3449 t->ret_stack = NULL;
3450 /* NULL must become visible to IRQs before we free it: */
3451 barrier();
3452
3453 kfree(ret_stack);
3454 }
3455
3456 void ftrace_graph_stop(void)
3457 {
3458 ftrace_stop();
3459 }
3460 #endif
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree