?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
af_packet: prevent information leak
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / ftrace.c
blob666880d051ef3cabac32d0c8ea931016a64b2a10
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 conversion 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 = iter->func_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 = rec;
1506
1507 return iter;
1508 }
1509
1510 static void reset_iter_read(struct ftrace_iterator *iter)
1511 {
1512 iter->pos = 0;
1513 iter->func_pos = 0;
1514 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
1515 }
1516
1517 static void *t_start(struct seq_file *m, loff_t *pos)
1518 {
1519 struct ftrace_iterator *iter = m->private;
1520 void *p = NULL;
1521 loff_t l;
1522
1523 mutex_lock(&ftrace_lock);
1524 /*
1525 * If an lseek was done, then reset and start from beginning.
1526 */
1527 if (*pos < iter->pos)
1528 reset_iter_read(iter);
1529
1530 /*
1531 * For set_ftrace_filter reading, if we have the filter
1532 * off, we can short cut and just print out that all
1533 * functions are enabled.
1534 */
1535 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1536 if (*pos > 0)
1537 return t_hash_start(m, pos);
1538 iter->flags |= FTRACE_ITER_PRINTALL;
1539 /* reset in case of seek/pread */
1540 iter->flags &= ~FTRACE_ITER_HASH;
1541 return iter;
1542 }
1543
1544 if (iter->flags & FTRACE_ITER_HASH)
1545 return t_hash_start(m, pos);
1546
1547 /*
1548 * Unfortunately, we need to restart at ftrace_pages_start
1549 * every time we let go of the ftrace_mutex. This is because
1550 * those pointers can change without the lock.
1551 */
1552 iter->pg = ftrace_pages_start;
1553 iter->idx = 0;
1554 for (l = 0; l <= *pos; ) {
1555 p = t_next(m, p, &l);
1556 if (!p)
1557 break;
1558 }
1559
1560 if (!p) {
1561 if (iter->flags & FTRACE_ITER_FILTER)
1562 return t_hash_start(m, pos);
1563
1564 return NULL;
1565 }
1566
1567 return iter;
1568 }
1569
1570 static void t_stop(struct seq_file *m, void *p)
1571 {
1572 mutex_unlock(&ftrace_lock);
1573 }
1574
1575 static int t_show(struct seq_file *m, void *v)
1576 {
1577 struct ftrace_iterator *iter = m->private;
1578 struct dyn_ftrace *rec;
1579
1580 if (iter->flags & FTRACE_ITER_HASH)
1581 return t_hash_show(m, iter);
1582
1583 if (iter->flags & FTRACE_ITER_PRINTALL) {
1584 seq_printf(m, "#### all functions enabled ####\n");
1585 return 0;
1586 }
1587
1588 rec = iter->func;
1589
1590 if (!rec)
1591 return 0;
1592
1593 seq_printf(m, "%ps\n", (void *)rec->ip);
1594
1595 return 0;
1596 }
1597
1598 static const struct seq_operations show_ftrace_seq_ops = {
1599 .start = t_start,
1600 .next = t_next,
1601 .stop = t_stop,
1602 .show = t_show,
1603 };
1604
1605 static int
1606 ftrace_avail_open(struct inode *inode, struct file *file)
1607 {
1608 struct ftrace_iterator *iter;
1609 int ret;
1610
1611 if (unlikely(ftrace_disabled))
1612 return -ENODEV;
1613
1614 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1615 if (!iter)
1616 return -ENOMEM;
1617
1618 iter->pg = ftrace_pages_start;
1619
1620 ret = seq_open(file, &show_ftrace_seq_ops);
1621 if (!ret) {
1622 struct seq_file *m = file->private_data;
1623
1624 m->private = iter;
1625 } else {
1626 kfree(iter);
1627 }
1628
1629 return ret;
1630 }
1631
1632 static int
1633 ftrace_failures_open(struct inode *inode, struct file *file)
1634 {
1635 int ret;
1636 struct seq_file *m;
1637 struct ftrace_iterator *iter;
1638
1639 ret = ftrace_avail_open(inode, file);
1640 if (!ret) {
1641 m = file->private_data;
1642 iter = m->private;
1643 iter->flags = FTRACE_ITER_FAILURES;
1644 }
1645
1646 return ret;
1647 }
1648
1649
1650 static void ftrace_filter_reset(int enable)
1651 {
1652 struct ftrace_page *pg;
1653 struct dyn_ftrace *rec;
1654 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1655
1656 mutex_lock(&ftrace_lock);
1657 if (enable)
1658 ftrace_filtered = 0;
1659 do_for_each_ftrace_rec(pg, rec) {
1660 if (rec->flags & FTRACE_FL_FAILED)
1661 continue;
1662 rec->flags &= ~type;
1663 } while_for_each_ftrace_rec();
1664 mutex_unlock(&ftrace_lock);
1665 }
1666
1667 static int
1668 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1669 {
1670 struct ftrace_iterator *iter;
1671 int ret = 0;
1672
1673 if (unlikely(ftrace_disabled))
1674 return -ENODEV;
1675
1676 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1677 if (!iter)
1678 return -ENOMEM;
1679
1680 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1681 kfree(iter);
1682 return -ENOMEM;
1683 }
1684
1685 mutex_lock(&ftrace_regex_lock);
1686 if ((file->f_mode & FMODE_WRITE) &&
1687 (file->f_flags & O_TRUNC))
1688 ftrace_filter_reset(enable);
1689
1690 if (file->f_mode & FMODE_READ) {
1691 iter->pg = ftrace_pages_start;
1692 iter->flags = enable ? FTRACE_ITER_FILTER :
1693 FTRACE_ITER_NOTRACE;
1694
1695 ret = seq_open(file, &show_ftrace_seq_ops);
1696 if (!ret) {
1697 struct seq_file *m = file->private_data;
1698 m->private = iter;
1699 } else {
1700 trace_parser_put(&iter->parser);
1701 kfree(iter);
1702 }
1703 } else
1704 file->private_data = iter;
1705 mutex_unlock(&ftrace_regex_lock);
1706
1707 return ret;
1708 }
1709
1710 static int
1711 ftrace_filter_open(struct inode *inode, struct file *file)
1712 {
1713 return ftrace_regex_open(inode, file, 1);
1714 }
1715
1716 static int
1717 ftrace_notrace_open(struct inode *inode, struct file *file)
1718 {
1719 return ftrace_regex_open(inode, file, 0);
1720 }
1721
1722 static loff_t
1723 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1724 {
1725 loff_t ret;
1726
1727 if (file->f_mode & FMODE_READ)
1728 ret = seq_lseek(file, offset, origin);
1729 else
1730 file->f_pos = ret = 1;
1731
1732 return ret;
1733 }
1734
1735 static int ftrace_match(char *str, char *regex, int len, int type)
1736 {
1737 int matched = 0;
1738 int slen;
1739
1740 switch (type) {
1741 case MATCH_FULL:
1742 if (strcmp(str, regex) == 0)
1743 matched = 1;
1744 break;
1745 case MATCH_FRONT_ONLY:
1746 if (strncmp(str, regex, len) == 0)
1747 matched = 1;
1748 break;
1749 case MATCH_MIDDLE_ONLY:
1750 if (strstr(str, regex))
1751 matched = 1;
1752 break;
1753 case MATCH_END_ONLY:
1754 slen = strlen(str);
1755 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1756 matched = 1;
1757 break;
1758 }
1759
1760 return matched;
1761 }
1762
1763 static int
1764 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1765 {
1766 char str[KSYM_SYMBOL_LEN];
1767
1768 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1769 return ftrace_match(str, regex, len, type);
1770 }
1771
1772 static int ftrace_match_records(char *buff, int len, int enable)
1773 {
1774 unsigned int search_len;
1775 struct ftrace_page *pg;
1776 struct dyn_ftrace *rec;
1777 unsigned long flag;
1778 char *search;
1779 int type;
1780 int not;
1781 int found = 0;
1782
1783 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1784 type = filter_parse_regex(buff, len, &search, &not);
1785
1786 search_len = strlen(search);
1787
1788 mutex_lock(&ftrace_lock);
1789 do_for_each_ftrace_rec(pg, rec) {
1790
1791 if (rec->flags & FTRACE_FL_FAILED)
1792 continue;
1793
1794 if (ftrace_match_record(rec, search, search_len, type)) {
1795 if (not)
1796 rec->flags &= ~flag;
1797 else
1798 rec->flags |= flag;
1799 found = 1;
1800 }
1801 /*
1802 * Only enable filtering if we have a function that
1803 * is filtered on.
1804 */
1805 if (enable && (rec->flags & FTRACE_FL_FILTER))
1806 ftrace_filtered = 1;
1807 } while_for_each_ftrace_rec();
1808 mutex_unlock(&ftrace_lock);
1809
1810 return found;
1811 }
1812
1813 static int
1814 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1815 char *regex, int len, int type)
1816 {
1817 char str[KSYM_SYMBOL_LEN];
1818 char *modname;
1819
1820 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1821
1822 if (!modname || strcmp(modname, mod))
1823 return 0;
1824
1825 /* blank search means to match all funcs in the mod */
1826 if (len)
1827 return ftrace_match(str, regex, len, type);
1828 else
1829 return 1;
1830 }
1831
1832 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1833 {
1834 unsigned search_len = 0;
1835 struct ftrace_page *pg;
1836 struct dyn_ftrace *rec;
1837 int type = MATCH_FULL;
1838 char *search = buff;
1839 unsigned long flag;
1840 int not = 0;
1841 int found = 0;
1842
1843 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1844
1845 /* blank or '*' mean the same */
1846 if (strcmp(buff, "*") == 0)
1847 buff[0] = 0;
1848
1849 /* handle the case of 'dont filter this module' */
1850 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1851 buff[0] = 0;
1852 not = 1;
1853 }
1854
1855 if (strlen(buff)) {
1856 type = filter_parse_regex(buff, strlen(buff), &search, &not);
1857 search_len = strlen(search);
1858 }
1859
1860 mutex_lock(&ftrace_lock);
1861 do_for_each_ftrace_rec(pg, rec) {
1862
1863 if (rec->flags & FTRACE_FL_FAILED)
1864 continue;
1865
1866 if (ftrace_match_module_record(rec, mod,
1867 search, search_len, type)) {
1868 if (not)
1869 rec->flags &= ~flag;
1870 else
1871 rec->flags |= flag;
1872 found = 1;
1873 }
1874 if (enable && (rec->flags & FTRACE_FL_FILTER))
1875 ftrace_filtered = 1;
1876
1877 } while_for_each_ftrace_rec();
1878 mutex_unlock(&ftrace_lock);
1879
1880 return found;
1881 }
1882
1883 /*
1884 * We register the module command as a template to show others how
1885 * to register the a command as well.
1886 */
1887
1888 static int
1889 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1890 {
1891 char *mod;
1892
1893 /*
1894 * cmd == 'mod' because we only registered this func
1895 * for the 'mod' ftrace_func_command.
1896 * But if you register one func with multiple commands,
1897 * you can tell which command was used by the cmd
1898 * parameter.
1899 */
1900
1901 /* we must have a module name */
1902 if (!param)
1903 return -EINVAL;
1904
1905 mod = strsep(&param, ":");
1906 if (!strlen(mod))
1907 return -EINVAL;
1908
1909 if (ftrace_match_module_records(func, mod, enable))
1910 return 0;
1911 return -EINVAL;
1912 }
1913
1914 static struct ftrace_func_command ftrace_mod_cmd = {
1915 .name = "mod",
1916 .func = ftrace_mod_callback,
1917 };
1918
1919 static int __init ftrace_mod_cmd_init(void)
1920 {
1921 return register_ftrace_command(&ftrace_mod_cmd);
1922 }
1923 device_initcall(ftrace_mod_cmd_init);
1924
1925 static void
1926 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1927 {
1928 struct ftrace_func_probe *entry;
1929 struct hlist_head *hhd;
1930 struct hlist_node *n;
1931 unsigned long key;
1932
1933 key = hash_long(ip, FTRACE_HASH_BITS);
1934
1935 hhd = &ftrace_func_hash[key];
1936
1937 if (hlist_empty(hhd))
1938 return;
1939
1940 /*
1941 * Disable preemption for these calls to prevent a RCU grace
1942 * period. This syncs the hash iteration and freeing of items
1943 * on the hash. rcu_read_lock is too dangerous here.
1944 */
1945 preempt_disable_notrace();
1946 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1947 if (entry->ip == ip)
1948 entry->ops->func(ip, parent_ip, &entry->data);
1949 }
1950 preempt_enable_notrace();
1951 }
1952
1953 static struct ftrace_ops trace_probe_ops __read_mostly =
1954 {
1955 .func = function_trace_probe_call,
1956 };
1957
1958 static int ftrace_probe_registered;
1959
1960 static void __enable_ftrace_function_probe(void)
1961 {
1962 int i;
1963
1964 if (ftrace_probe_registered)
1965 return;
1966
1967 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1968 struct hlist_head *hhd = &ftrace_func_hash[i];
1969 if (hhd->first)
1970 break;
1971 }
1972 /* Nothing registered? */
1973 if (i == FTRACE_FUNC_HASHSIZE)
1974 return;
1975
1976 __register_ftrace_function(&trace_probe_ops);
1977 ftrace_startup(0);
1978 ftrace_probe_registered = 1;
1979 }
1980
1981 static void __disable_ftrace_function_probe(void)
1982 {
1983 int i;
1984
1985 if (!ftrace_probe_registered)
1986 return;
1987
1988 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1989 struct hlist_head *hhd = &ftrace_func_hash[i];
1990 if (hhd->first)
1991 return;
1992 }
1993
1994 /* no more funcs left */
1995 __unregister_ftrace_function(&trace_probe_ops);
1996 ftrace_shutdown(0);
1997 ftrace_probe_registered = 0;
1998 }
1999
2000
2001 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2002 {
2003 struct ftrace_func_probe *entry =
2004 container_of(rhp, struct ftrace_func_probe, rcu);
2005
2006 if (entry->ops->free)
2007 entry->ops->free(&entry->data);
2008 kfree(entry);
2009 }
2010
2011
2012 int
2013 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2014 void *data)
2015 {
2016 struct ftrace_func_probe *entry;
2017 struct ftrace_page *pg;
2018 struct dyn_ftrace *rec;
2019 int type, len, not;
2020 unsigned long key;
2021 int count = 0;
2022 char *search;
2023
2024 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2025 len = strlen(search);
2026
2027 /* we do not support '!' for function probes */
2028 if (WARN_ON(not))
2029 return -EINVAL;
2030
2031 mutex_lock(&ftrace_lock);
2032 do_for_each_ftrace_rec(pg, rec) {
2033
2034 if (rec->flags & FTRACE_FL_FAILED)
2035 continue;
2036
2037 if (!ftrace_match_record(rec, search, len, type))
2038 continue;
2039
2040 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2041 if (!entry) {
2042 /* If we did not process any, then return error */
2043 if (!count)
2044 count = -ENOMEM;
2045 goto out_unlock;
2046 }
2047
2048 count++;
2049
2050 entry->data = data;
2051
2052 /*
2053 * The caller might want to do something special
2054 * for each function we find. We call the callback
2055 * to give the caller an opportunity to do so.
2056 */
2057 if (ops->callback) {
2058 if (ops->callback(rec->ip, &entry->data) < 0) {
2059 /* caller does not like this func */
2060 kfree(entry);
2061 continue;
2062 }
2063 }
2064
2065 entry->ops = ops;
2066 entry->ip = rec->ip;
2067
2068 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2069 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2070
2071 } while_for_each_ftrace_rec();
2072 __enable_ftrace_function_probe();
2073
2074 out_unlock:
2075 mutex_unlock(&ftrace_lock);
2076
2077 return count;
2078 }
2079
2080 enum {
2081 PROBE_TEST_FUNC = 1,
2082 PROBE_TEST_DATA = 2
2083 };
2084
2085 static void
2086 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2087 void *data, int flags)
2088 {
2089 struct ftrace_func_probe *entry;
2090 struct hlist_node *n, *tmp;
2091 char str[KSYM_SYMBOL_LEN];
2092 int type = MATCH_FULL;
2093 int i, len = 0;
2094 char *search;
2095
2096 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2097 glob = NULL;
2098 else if (glob) {
2099 int not;
2100
2101 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2102 len = strlen(search);
2103
2104 /* we do not support '!' for function probes */
2105 if (WARN_ON(not))
2106 return;
2107 }
2108
2109 mutex_lock(&ftrace_lock);
2110 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2111 struct hlist_head *hhd = &ftrace_func_hash[i];
2112
2113 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2114
2115 /* break up if statements for readability */
2116 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2117 continue;
2118
2119 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2120 continue;
2121
2122 /* do this last, since it is the most expensive */
2123 if (glob) {
2124 kallsyms_lookup(entry->ip, NULL, NULL,
2125 NULL, str);
2126 if (!ftrace_match(str, glob, len, type))
2127 continue;
2128 }
2129
2130 hlist_del(&entry->node);
2131 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2132 }
2133 }
2134 __disable_ftrace_function_probe();
2135 mutex_unlock(&ftrace_lock);
2136 }
2137
2138 void
2139 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2140 void *data)
2141 {
2142 __unregister_ftrace_function_probe(glob, ops, data,
2143 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2144 }
2145
2146 void
2147 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2148 {
2149 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2150 }
2151
2152 void unregister_ftrace_function_probe_all(char *glob)
2153 {
2154 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2155 }
2156
2157 static LIST_HEAD(ftrace_commands);
2158 static DEFINE_MUTEX(ftrace_cmd_mutex);
2159
2160 int register_ftrace_command(struct ftrace_func_command *cmd)
2161 {
2162 struct ftrace_func_command *p;
2163 int ret = 0;
2164
2165 mutex_lock(&ftrace_cmd_mutex);
2166 list_for_each_entry(p, &ftrace_commands, list) {
2167 if (strcmp(cmd->name, p->name) == 0) {
2168 ret = -EBUSY;
2169 goto out_unlock;
2170 }
2171 }
2172 list_add(&cmd->list, &ftrace_commands);
2173 out_unlock:
2174 mutex_unlock(&ftrace_cmd_mutex);
2175
2176 return ret;
2177 }
2178
2179 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2180 {
2181 struct ftrace_func_command *p, *n;
2182 int ret = -ENODEV;
2183
2184 mutex_lock(&ftrace_cmd_mutex);
2185 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2186 if (strcmp(cmd->name, p->name) == 0) {
2187 ret = 0;
2188 list_del_init(&p->list);
2189 goto out_unlock;
2190 }
2191 }
2192 out_unlock:
2193 mutex_unlock(&ftrace_cmd_mutex);
2194
2195 return ret;
2196 }
2197
2198 static int ftrace_process_regex(char *buff, int len, int enable)
2199 {
2200 char *func, *command, *next = buff;
2201 struct ftrace_func_command *p;
2202 int ret = -EINVAL;
2203
2204 func = strsep(&next, ":");
2205
2206 if (!next) {
2207 if (ftrace_match_records(func, len, enable))
2208 return 0;
2209 return ret;
2210 }
2211
2212 /* command found */
2213
2214 command = strsep(&next, ":");
2215
2216 mutex_lock(&ftrace_cmd_mutex);
2217 list_for_each_entry(p, &ftrace_commands, list) {
2218 if (strcmp(p->name, command) == 0) {
2219 ret = p->func(func, command, next, enable);
2220 goto out_unlock;
2221 }
2222 }
2223 out_unlock:
2224 mutex_unlock(&ftrace_cmd_mutex);
2225
2226 return ret;
2227 }
2228
2229 static ssize_t
2230 ftrace_regex_write(struct file *file, const char __user *ubuf,
2231 size_t cnt, loff_t *ppos, int enable)
2232 {
2233 struct ftrace_iterator *iter;
2234 struct trace_parser *parser;
2235 ssize_t ret, read;
2236
2237 if (!cnt)
2238 return 0;
2239
2240 mutex_lock(&ftrace_regex_lock);
2241
2242 if (file->f_mode & FMODE_READ) {
2243 struct seq_file *m = file->private_data;
2244 iter = m->private;
2245 } else
2246 iter = file->private_data;
2247
2248 parser = &iter->parser;
2249 read = trace_get_user(parser, ubuf, cnt, ppos);
2250
2251 if (read >= 0 && trace_parser_loaded(parser) &&
2252 !trace_parser_cont(parser)) {
2253 ret = ftrace_process_regex(parser->buffer,
2254 parser->idx, enable);
2255 trace_parser_clear(parser);
2256 if (ret)
2257 goto out_unlock;
2258 }
2259
2260 ret = read;
2261 out_unlock:
2262 mutex_unlock(&ftrace_regex_lock);
2263
2264 return ret;
2265 }
2266
2267 static ssize_t
2268 ftrace_filter_write(struct file *file, const char __user *ubuf,
2269 size_t cnt, loff_t *ppos)
2270 {
2271 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2272 }
2273
2274 static ssize_t
2275 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2276 size_t cnt, loff_t *ppos)
2277 {
2278 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2279 }
2280
2281 static void
2282 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2283 {
2284 if (unlikely(ftrace_disabled))
2285 return;
2286
2287 mutex_lock(&ftrace_regex_lock);
2288 if (reset)
2289 ftrace_filter_reset(enable);
2290 if (buf)
2291 ftrace_match_records(buf, len, enable);
2292 mutex_unlock(&ftrace_regex_lock);
2293 }
2294
2295 /**
2296 * ftrace_set_filter - set a function to filter on in ftrace
2297 * @buf - the string that holds the function filter text.
2298 * @len - the length of the string.
2299 * @reset - non zero to reset all filters before applying this filter.
2300 *
2301 * Filters denote which functions should be enabled when tracing is enabled.
2302 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2303 */
2304 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2305 {
2306 ftrace_set_regex(buf, len, reset, 1);
2307 }
2308
2309 /**
2310 * ftrace_set_notrace - set a function to not trace in ftrace
2311 * @buf - the string that holds the function notrace text.
2312 * @len - the length of the string.
2313 * @reset - non zero to reset all filters before applying this filter.
2314 *
2315 * Notrace Filters denote which functions should not be enabled when tracing
2316 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2317 * for tracing.
2318 */
2319 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2320 {
2321 ftrace_set_regex(buf, len, reset, 0);
2322 }
2323
2324 /*
2325 * command line interface to allow users to set filters on boot up.
2326 */
2327 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2328 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2329 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2330
2331 static int __init set_ftrace_notrace(char *str)
2332 {
2333 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2334 return 1;
2335 }
2336 __setup("ftrace_notrace=", set_ftrace_notrace);
2337
2338 static int __init set_ftrace_filter(char *str)
2339 {
2340 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2341 return 1;
2342 }
2343 __setup("ftrace_filter=", set_ftrace_filter);
2344
2345 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2346 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2347 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
2348
2349 static int __init set_graph_function(char *str)
2350 {
2351 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2352 return 1;
2353 }
2354 __setup("ftrace_graph_filter=", set_graph_function);
2355
2356 static void __init set_ftrace_early_graph(char *buf)
2357 {
2358 int ret;
2359 char *func;
2360
2361 while (buf) {
2362 func = strsep(&buf, ",");
2363 /* we allow only one expression at a time */
2364 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2365 func);
2366 if (ret)
2367 printk(KERN_DEBUG "ftrace: function %s not "
2368 "traceable\n", func);
2369 }
2370 }
2371 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2372
2373 static void __init set_ftrace_early_filter(char *buf, int enable)
2374 {
2375 char *func;
2376
2377 while (buf) {
2378 func = strsep(&buf, ",");
2379 ftrace_set_regex(func, strlen(func), 0, enable);
2380 }
2381 }
2382
2383 static void __init set_ftrace_early_filters(void)
2384 {
2385 if (ftrace_filter_buf[0])
2386 set_ftrace_early_filter(ftrace_filter_buf, 1);
2387 if (ftrace_notrace_buf[0])
2388 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2389 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2390 if (ftrace_graph_buf[0])
2391 set_ftrace_early_graph(ftrace_graph_buf);
2392 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2393 }
2394
2395 static int
2396 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2397 {
2398 struct seq_file *m = (struct seq_file *)file->private_data;
2399 struct ftrace_iterator *iter;
2400 struct trace_parser *parser;
2401
2402 mutex_lock(&ftrace_regex_lock);
2403 if (file->f_mode & FMODE_READ) {
2404 iter = m->private;
2405
2406 seq_release(inode, file);
2407 } else
2408 iter = file->private_data;
2409
2410 parser = &iter->parser;
2411 if (trace_parser_loaded(parser)) {
2412 parser->buffer[parser->idx] = 0;
2413 ftrace_match_records(parser->buffer, parser->idx, enable);
2414 }
2415
2416 trace_parser_put(parser);
2417 kfree(iter);
2418
2419 if (file->f_mode & FMODE_WRITE) {
2420 mutex_lock(&ftrace_lock);
2421 if (ftrace_start_up && ftrace_enabled)
2422 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2423 mutex_unlock(&ftrace_lock);
2424 }
2425
2426 mutex_unlock(&ftrace_regex_lock);
2427 return 0;
2428 }
2429
2430 static int
2431 ftrace_filter_release(struct inode *inode, struct file *file)
2432 {
2433 return ftrace_regex_release(inode, file, 1);
2434 }
2435
2436 static int
2437 ftrace_notrace_release(struct inode *inode, struct file *file)
2438 {
2439 return ftrace_regex_release(inode, file, 0);
2440 }
2441
2442 static const struct file_operations ftrace_avail_fops = {
2443 .open = ftrace_avail_open,
2444 .read = seq_read,
2445 .llseek = seq_lseek,
2446 .release = seq_release_private,
2447 };
2448
2449 static const struct file_operations ftrace_failures_fops = {
2450 .open = ftrace_failures_open,
2451 .read = seq_read,
2452 .llseek = seq_lseek,
2453 .release = seq_release_private,
2454 };
2455
2456 static const struct file_operations ftrace_filter_fops = {
2457 .open = ftrace_filter_open,
2458 .read = seq_read,
2459 .write = ftrace_filter_write,
2460 .llseek = ftrace_regex_lseek,
2461 .release = ftrace_filter_release,
2462 };
2463
2464 static const struct file_operations ftrace_notrace_fops = {
2465 .open = ftrace_notrace_open,
2466 .read = seq_read,
2467 .write = ftrace_notrace_write,
2468 .llseek = ftrace_regex_lseek,
2469 .release = ftrace_notrace_release,
2470 };
2471
2472 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2473
2474 static DEFINE_MUTEX(graph_lock);
2475
2476 int ftrace_graph_count;
2477 int ftrace_graph_filter_enabled;
2478 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2479
2480 static void *
2481 __g_next(struct seq_file *m, loff_t *pos)
2482 {
2483 if (*pos >= ftrace_graph_count)
2484 return NULL;
2485 return &ftrace_graph_funcs[*pos];
2486 }
2487
2488 static void *
2489 g_next(struct seq_file *m, void *v, loff_t *pos)
2490 {
2491 (*pos)++;
2492 return __g_next(m, pos);
2493 }
2494
2495 static void *g_start(struct seq_file *m, loff_t *pos)
2496 {
2497 mutex_lock(&graph_lock);
2498
2499 /* Nothing, tell g_show to print all functions are enabled */
2500 if (!ftrace_graph_filter_enabled && !*pos)
2501 return (void *)1;
2502
2503 return __g_next(m, pos);
2504 }
2505
2506 static void g_stop(struct seq_file *m, void *p)
2507 {
2508 mutex_unlock(&graph_lock);
2509 }
2510
2511 static int g_show(struct seq_file *m, void *v)
2512 {
2513 unsigned long *ptr = v;
2514
2515 if (!ptr)
2516 return 0;
2517
2518 if (ptr == (unsigned long *)1) {
2519 seq_printf(m, "#### all functions enabled ####\n");
2520 return 0;
2521 }
2522
2523 seq_printf(m, "%ps\n", (void *)*ptr);
2524
2525 return 0;
2526 }
2527
2528 static const struct seq_operations ftrace_graph_seq_ops = {
2529 .start = g_start,
2530 .next = g_next,
2531 .stop = g_stop,
2532 .show = g_show,
2533 };
2534
2535 static int
2536 ftrace_graph_open(struct inode *inode, struct file *file)
2537 {
2538 int ret = 0;
2539
2540 if (unlikely(ftrace_disabled))
2541 return -ENODEV;
2542
2543 mutex_lock(&graph_lock);
2544 if ((file->f_mode & FMODE_WRITE) &&
2545 (file->f_flags & O_TRUNC)) {
2546 ftrace_graph_filter_enabled = 0;
2547 ftrace_graph_count = 0;
2548 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2549 }
2550 mutex_unlock(&graph_lock);
2551
2552 if (file->f_mode & FMODE_READ)
2553 ret = seq_open(file, &ftrace_graph_seq_ops);
2554
2555 return ret;
2556 }
2557
2558 static int
2559 ftrace_graph_release(struct inode *inode, struct file *file)
2560 {
2561 if (file->f_mode & FMODE_READ)
2562 seq_release(inode, file);
2563 return 0;
2564 }
2565
2566 static int
2567 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2568 {
2569 struct dyn_ftrace *rec;
2570 struct ftrace_page *pg;
2571 int search_len;
2572 int fail = 1;
2573 int type, not;
2574 char *search;
2575 bool exists;
2576 int i;
2577
2578 if (ftrace_disabled)
2579 return -ENODEV;
2580
2581 /* decode regex */
2582 type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
2583 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
2584 return -EBUSY;
2585
2586 search_len = strlen(search);
2587
2588 mutex_lock(&ftrace_lock);
2589 do_for_each_ftrace_rec(pg, rec) {
2590
2591 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2592 continue;
2593
2594 if (ftrace_match_record(rec, search, search_len, type)) {
2595 /* if it is in the array */
2596 exists = false;
2597 for (i = 0; i < *idx; i++) {
2598 if (array[i] == rec->ip) {
2599 exists = true;
2600 break;
2601 }
2602 }
2603
2604 if (!not) {
2605 fail = 0;
2606 if (!exists) {
2607 array[(*idx)++] = rec->ip;
2608 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2609 goto out;
2610 }
2611 } else {
2612 if (exists) {
2613 array[i] = array[--(*idx)];
2614 array[*idx] = 0;
2615 fail = 0;
2616 }
2617 }
2618 }
2619 } while_for_each_ftrace_rec();
2620 out:
2621 mutex_unlock(&ftrace_lock);
2622
2623 if (fail)
2624 return -EINVAL;
2625
2626 ftrace_graph_filter_enabled = 1;
2627 return 0;
2628 }
2629
2630 static ssize_t
2631 ftrace_graph_write(struct file *file, const char __user *ubuf,
2632 size_t cnt, loff_t *ppos)
2633 {
2634 struct trace_parser parser;
2635 ssize_t read, ret;
2636
2637 if (!cnt)
2638 return 0;
2639
2640 mutex_lock(&graph_lock);
2641
2642 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2643 ret = -ENOMEM;
2644 goto out_unlock;
2645 }
2646
2647 read = trace_get_user(&parser, ubuf, cnt, ppos);
2648
2649 if (read >= 0 && trace_parser_loaded((&parser))) {
2650 parser.buffer[parser.idx] = 0;
2651
2652 /* we allow only one expression at a time */
2653 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2654 parser.buffer);
2655 if (ret)
2656 goto out_free;
2657 }
2658
2659 ret = read;
2660
2661 out_free:
2662 trace_parser_put(&parser);
2663 out_unlock:
2664 mutex_unlock(&graph_lock);
2665
2666 return ret;
2667 }
2668
2669 static const struct file_operations ftrace_graph_fops = {
2670 .open = ftrace_graph_open,
2671 .read = seq_read,
2672 .write = ftrace_graph_write,
2673 .release = ftrace_graph_release,
2674 .llseek = seq_lseek,
2675 };
2676 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2677
2678 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2679 {
2680
2681 trace_create_file("available_filter_functions", 0444,
2682 d_tracer, NULL, &ftrace_avail_fops);
2683
2684 trace_create_file("failures", 0444,
2685 d_tracer, NULL, &ftrace_failures_fops);
2686
2687 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2688 NULL, &ftrace_filter_fops);
2689
2690 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2691 NULL, &ftrace_notrace_fops);
2692
2693 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2694 trace_create_file("set_graph_function", 0444, d_tracer,
2695 NULL,
2696 &ftrace_graph_fops);
2697 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2698
2699 return 0;
2700 }
2701
2702 static int ftrace_process_locs(struct module *mod,
2703 unsigned long *start,
2704 unsigned long *end)
2705 {
2706 unsigned long *p;
2707 unsigned long addr;
2708 unsigned long flags;
2709
2710 mutex_lock(&ftrace_lock);
2711 p = start;
2712 while (p < end) {
2713 addr = ftrace_call_adjust(*p++);
2714 /*
2715 * Some architecture linkers will pad between
2716 * the different mcount_loc sections of different
2717 * object files to satisfy alignments.
2718 * Skip any NULL pointers.
2719 */
2720 if (!addr)
2721 continue;
2722 ftrace_record_ip(addr);
2723 }
2724
2725 /* disable interrupts to prevent kstop machine */
2726 local_irq_save(flags);
2727 ftrace_update_code(mod);
2728 local_irq_restore(flags);
2729 mutex_unlock(&ftrace_lock);
2730
2731 return 0;
2732 }
2733
2734 #ifdef CONFIG_MODULES
2735 void ftrace_release_mod(struct module *mod)
2736 {
2737 struct dyn_ftrace *rec;
2738 struct ftrace_page *pg;
2739
2740 if (ftrace_disabled)
2741 return;
2742
2743 mutex_lock(&ftrace_lock);
2744 do_for_each_ftrace_rec(pg, rec) {
2745 if (within_module_core(rec->ip, mod)) {
2746 /*
2747 * rec->ip is changed in ftrace_free_rec()
2748 * It should not between s and e if record was freed.
2749 */
2750 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2751 ftrace_free_rec(rec);
2752 }
2753 } while_for_each_ftrace_rec();
2754 mutex_unlock(&ftrace_lock);
2755 }
2756
2757 static void ftrace_init_module(struct module *mod,
2758 unsigned long *start, unsigned long *end)
2759 {
2760 if (ftrace_disabled || start == end)
2761 return;
2762 ftrace_process_locs(mod, start, end);
2763 }
2764
2765 static int ftrace_module_notify(struct notifier_block *self,
2766 unsigned long val, void *data)
2767 {
2768 struct module *mod = data;
2769
2770 switch (val) {
2771 case MODULE_STATE_COMING:
2772 ftrace_init_module(mod, mod->ftrace_callsites,
2773 mod->ftrace_callsites +
2774 mod->num_ftrace_callsites);
2775 break;
2776 case MODULE_STATE_GOING:
2777 ftrace_release_mod(mod);
2778 break;
2779 }
2780
2781 return 0;
2782 }
2783 #else
2784 static int ftrace_module_notify(struct notifier_block *self,
2785 unsigned long val, void *data)
2786 {
2787 return 0;
2788 }
2789 #endif /* CONFIG_MODULES */
2790
2791 struct notifier_block ftrace_module_nb = {
2792 .notifier_call = ftrace_module_notify,
2793 .priority = 0,
2794 };
2795
2796 extern unsigned long __start_mcount_loc[];
2797 extern unsigned long __stop_mcount_loc[];
2798
2799 void __init ftrace_init(void)
2800 {
2801 unsigned long count, addr, flags;
2802 int ret;
2803
2804 /* Keep the ftrace pointer to the stub */
2805 addr = (unsigned long)ftrace_stub;
2806
2807 local_irq_save(flags);
2808 ftrace_dyn_arch_init(&addr);
2809 local_irq_restore(flags);
2810
2811 /* ftrace_dyn_arch_init places the return code in addr */
2812 if (addr)
2813 goto failed;
2814
2815 count = __stop_mcount_loc - __start_mcount_loc;
2816
2817 ret = ftrace_dyn_table_alloc(count);
2818 if (ret)
2819 goto failed;
2820
2821 last_ftrace_enabled = ftrace_enabled = 1;
2822
2823 ret = ftrace_process_locs(NULL,
2824 __start_mcount_loc,
2825 __stop_mcount_loc);
2826
2827 ret = register_module_notifier(&ftrace_module_nb);
2828 if (ret)
2829 pr_warning("Failed to register trace ftrace module notifier\n");
2830
2831 set_ftrace_early_filters();
2832
2833 return;
2834 failed:
2835 ftrace_disabled = 1;
2836 }
2837
2838 #else
2839
2840 static int __init ftrace_nodyn_init(void)
2841 {
2842 ftrace_enabled = 1;
2843 return 0;
2844 }
2845 device_initcall(ftrace_nodyn_init);
2846
2847 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2848 static inline void ftrace_startup_enable(int command) { }
2849 /* Keep as macros so we do not need to define the commands */
2850 # define ftrace_startup(command) do { } while (0)
2851 # define ftrace_shutdown(command) do { } while (0)
2852 # define ftrace_startup_sysctl() do { } while (0)
2853 # define ftrace_shutdown_sysctl() do { } while (0)
2854 #endif /* CONFIG_DYNAMIC_FTRACE */
2855
2856 static void clear_ftrace_swapper(void)
2857 {
2858 struct task_struct *p;
2859 int cpu;
2860
2861 get_online_cpus();
2862 for_each_online_cpu(cpu) {
2863 p = idle_task(cpu);
2864 clear_tsk_trace_trace(p);
2865 }
2866 put_online_cpus();
2867 }
2868
2869 static void set_ftrace_swapper(void)
2870 {
2871 struct task_struct *p;
2872 int cpu;
2873
2874 get_online_cpus();
2875 for_each_online_cpu(cpu) {
2876 p = idle_task(cpu);
2877 set_tsk_trace_trace(p);
2878 }
2879 put_online_cpus();
2880 }
2881
2882 static void clear_ftrace_pid(struct pid *pid)
2883 {
2884 struct task_struct *p;
2885
2886 rcu_read_lock();
2887 do_each_pid_task(pid, PIDTYPE_PID, p) {
2888 clear_tsk_trace_trace(p);
2889 } while_each_pid_task(pid, PIDTYPE_PID, p);
2890 rcu_read_unlock();
2891
2892 put_pid(pid);
2893 }
2894
2895 static void set_ftrace_pid(struct pid *pid)
2896 {
2897 struct task_struct *p;
2898
2899 rcu_read_lock();
2900 do_each_pid_task(pid, PIDTYPE_PID, p) {
2901 set_tsk_trace_trace(p);
2902 } while_each_pid_task(pid, PIDTYPE_PID, p);
2903 rcu_read_unlock();
2904 }
2905
2906 static void clear_ftrace_pid_task(struct pid *pid)
2907 {
2908 if (pid == ftrace_swapper_pid)
2909 clear_ftrace_swapper();
2910 else
2911 clear_ftrace_pid(pid);
2912 }
2913
2914 static void set_ftrace_pid_task(struct pid *pid)
2915 {
2916 if (pid == ftrace_swapper_pid)
2917 set_ftrace_swapper();
2918 else
2919 set_ftrace_pid(pid);
2920 }
2921
2922 static int ftrace_pid_add(int p)
2923 {
2924 struct pid *pid;
2925 struct ftrace_pid *fpid;
2926 int ret = -EINVAL;
2927
2928 mutex_lock(&ftrace_lock);
2929
2930 if (!p)
2931 pid = ftrace_swapper_pid;
2932 else
2933 pid = find_get_pid(p);
2934
2935 if (!pid)
2936 goto out;
2937
2938 ret = 0;
2939
2940 list_for_each_entry(fpid, &ftrace_pids, list)
2941 if (fpid->pid == pid)
2942 goto out_put;
2943
2944 ret = -ENOMEM;
2945
2946 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2947 if (!fpid)
2948 goto out_put;
2949
2950 list_add(&fpid->list, &ftrace_pids);
2951 fpid->pid = pid;
2952
2953 set_ftrace_pid_task(pid);
2954
2955 ftrace_update_pid_func();
2956 ftrace_startup_enable(0);
2957
2958 mutex_unlock(&ftrace_lock);
2959 return 0;
2960
2961 out_put:
2962 if (pid != ftrace_swapper_pid)
2963 put_pid(pid);
2964
2965 out:
2966 mutex_unlock(&ftrace_lock);
2967 return ret;
2968 }
2969
2970 static void ftrace_pid_reset(void)
2971 {
2972 struct ftrace_pid *fpid, *safe;
2973
2974 mutex_lock(&ftrace_lock);
2975 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2976 struct pid *pid = fpid->pid;
2977
2978 clear_ftrace_pid_task(pid);
2979
2980 list_del(&fpid->list);
2981 kfree(fpid);
2982 }
2983
2984 ftrace_update_pid_func();
2985 ftrace_startup_enable(0);
2986
2987 mutex_unlock(&ftrace_lock);
2988 }
2989
2990 static void *fpid_start(struct seq_file *m, loff_t *pos)
2991 {
2992 mutex_lock(&ftrace_lock);
2993
2994 if (list_empty(&ftrace_pids) && (!*pos))
2995 return (void *) 1;
2996
2997 return seq_list_start(&ftrace_pids, *pos);
2998 }
2999
3000 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3001 {
3002 if (v == (void *)1)
3003 return NULL;
3004
3005 return seq_list_next(v, &ftrace_pids, pos);
3006 }
3007
3008 static void fpid_stop(struct seq_file *m, void *p)
3009 {
3010 mutex_unlock(&ftrace_lock);
3011 }
3012
3013 static int fpid_show(struct seq_file *m, void *v)
3014 {
3015 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3016
3017 if (v == (void *)1) {
3018 seq_printf(m, "no pid\n");
3019 return 0;
3020 }
3021
3022 if (fpid->pid == ftrace_swapper_pid)
3023 seq_printf(m, "swapper tasks\n");
3024 else
3025 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3026
3027 return 0;
3028 }
3029
3030 static const struct seq_operations ftrace_pid_sops = {
3031 .start = fpid_start,
3032 .next = fpid_next,
3033 .stop = fpid_stop,
3034 .show = fpid_show,
3035 };
3036
3037 static int
3038 ftrace_pid_open(struct inode *inode, struct file *file)
3039 {
3040 int ret = 0;
3041
3042 if ((file->f_mode & FMODE_WRITE) &&
3043 (file->f_flags & O_TRUNC))
3044 ftrace_pid_reset();
3045
3046 if (file->f_mode & FMODE_READ)
3047 ret = seq_open(file, &ftrace_pid_sops);
3048
3049 return ret;
3050 }
3051
3052 static ssize_t
3053 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3054 size_t cnt, loff_t *ppos)
3055 {
3056 char buf[64], *tmp;
3057 long val;
3058 int ret;
3059
3060 if (cnt >= sizeof(buf))
3061 return -EINVAL;
3062
3063 if (copy_from_user(&buf, ubuf, cnt))
3064 return -EFAULT;
3065
3066 buf[cnt] = 0;
3067
3068 /*
3069 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3070 * to clean the filter quietly.
3071 */
3072 tmp = strstrip(buf);
3073 if (strlen(tmp) == 0)
3074 return 1;
3075
3076 ret = strict_strtol(tmp, 10, &val);
3077 if (ret < 0)
3078 return ret;
3079
3080 ret = ftrace_pid_add(val);
3081
3082 return ret ? ret : cnt;
3083 }
3084
3085 static int
3086 ftrace_pid_release(struct inode *inode, struct file *file)
3087 {
3088 if (file->f_mode & FMODE_READ)
3089 seq_release(inode, file);
3090
3091 return 0;
3092 }
3093
3094 static const struct file_operations ftrace_pid_fops = {
3095 .open = ftrace_pid_open,
3096 .write = ftrace_pid_write,
3097 .read = seq_read,
3098 .llseek = seq_lseek,
3099 .release = ftrace_pid_release,
3100 };
3101
3102 static __init int ftrace_init_debugfs(void)
3103 {
3104 struct dentry *d_tracer;
3105
3106 d_tracer = tracing_init_dentry();
3107 if (!d_tracer)
3108 return 0;
3109
3110 ftrace_init_dyn_debugfs(d_tracer);
3111
3112 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3113 NULL, &ftrace_pid_fops);
3114
3115 ftrace_profile_debugfs(d_tracer);
3116
3117 return 0;
3118 }
3119 fs_initcall(ftrace_init_debugfs);
3120
3121 /**
3122 * ftrace_kill - kill ftrace
3123 *
3124 * This function should be used by panic code. It stops ftrace
3125 * but in a not so nice way. If you need to simply kill ftrace
3126 * from a non-atomic section, use ftrace_kill.
3127 */
3128 void ftrace_kill(void)
3129 {
3130 ftrace_disabled = 1;
3131 ftrace_enabled = 0;
3132 clear_ftrace_function();
3133 }
3134
3135 /**
3136 * register_ftrace_function - register a function for profiling
3137 * @ops - ops structure that holds the function for profiling.
3138 *
3139 * Register a function to be called by all functions in the
3140 * kernel.
3141 *
3142 * Note: @ops->func and all the functions it calls must be labeled
3143 * with "notrace", otherwise it will go into a
3144 * recursive loop.
3145 */
3146 int register_ftrace_function(struct ftrace_ops *ops)
3147 {
3148 int ret;
3149
3150 if (unlikely(ftrace_disabled))
3151 return -1;
3152
3153 mutex_lock(&ftrace_lock);
3154
3155 ret = __register_ftrace_function(ops);
3156 ftrace_startup(0);
3157
3158 mutex_unlock(&ftrace_lock);
3159 return ret;
3160 }
3161
3162 /**
3163 * unregister_ftrace_function - unregister a function for profiling.
3164 * @ops - ops structure that holds the function to unregister
3165 *
3166 * Unregister a function that was added to be called by ftrace profiling.
3167 */
3168 int unregister_ftrace_function(struct ftrace_ops *ops)
3169 {
3170 int ret;
3171
3172 mutex_lock(&ftrace_lock);
3173 ret = __unregister_ftrace_function(ops);
3174 ftrace_shutdown(0);
3175 mutex_unlock(&ftrace_lock);
3176
3177 return ret;
3178 }
3179
3180 int
3181 ftrace_enable_sysctl(struct ctl_table *table, int write,
3182 void __user *buffer, size_t *lenp,
3183 loff_t *ppos)
3184 {
3185 int ret;
3186
3187 if (unlikely(ftrace_disabled))
3188 return -ENODEV;
3189
3190 mutex_lock(&ftrace_lock);
3191
3192 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3193
3194 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3195 goto out;
3196
3197 last_ftrace_enabled = !!ftrace_enabled;
3198
3199 if (ftrace_enabled) {
3200
3201 ftrace_startup_sysctl();
3202
3203 /* we are starting ftrace again */
3204 if (ftrace_list != &ftrace_list_end) {
3205 if (ftrace_list->next == &ftrace_list_end)
3206 ftrace_trace_function = ftrace_list->func;
3207 else
3208 ftrace_trace_function = ftrace_list_func;
3209 }
3210
3211 } else {
3212 /* stopping ftrace calls (just send to ftrace_stub) */
3213 ftrace_trace_function = ftrace_stub;
3214
3215 ftrace_shutdown_sysctl();
3216 }
3217
3218 out:
3219 mutex_unlock(&ftrace_lock);
3220 return ret;
3221 }
3222
3223 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3224
3225 static int ftrace_graph_active;
3226 static struct notifier_block ftrace_suspend_notifier;
3227
3228 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3229 {
3230 return 0;
3231 }
3232
3233 /* The callbacks that hook a function */
3234 trace_func_graph_ret_t ftrace_graph_return =
3235 (trace_func_graph_ret_t)ftrace_stub;
3236 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3237
3238 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3239 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3240 {
3241 int i;
3242 int ret = 0;
3243 unsigned long flags;
3244 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3245 struct task_struct *g, *t;
3246
3247 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3248 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3249 * sizeof(struct ftrace_ret_stack),
3250 GFP_KERNEL);
3251 if (!ret_stack_list[i]) {
3252 start = 0;
3253 end = i;
3254 ret = -ENOMEM;
3255 goto free;
3256 }
3257 }
3258
3259 read_lock_irqsave(&tasklist_lock, flags);
3260 do_each_thread(g, t) {
3261 if (start == end) {
3262 ret = -EAGAIN;
3263 goto unlock;
3264 }
3265
3266 if (t->ret_stack == NULL) {
3267 atomic_set(&t->tracing_graph_pause, 0);
3268 atomic_set(&t->trace_overrun, 0);
3269 t->curr_ret_stack = -1;
3270 /* Make sure the tasks see the -1 first: */
3271 smp_wmb();
3272 t->ret_stack = ret_stack_list[start++];
3273 }
3274 } while_each_thread(g, t);
3275
3276 unlock:
3277 read_unlock_irqrestore(&tasklist_lock, flags);
3278 free:
3279 for (i = start; i < end; i++)
3280 kfree(ret_stack_list[i]);
3281 return ret;
3282 }
3283
3284 static void
3285 ftrace_graph_probe_sched_switch(void *ignore,
3286 struct task_struct *prev, struct task_struct *next)
3287 {
3288 unsigned long long timestamp;
3289 int index;
3290
3291 /*
3292 * Does the user want to count the time a function was asleep.
3293 * If so, do not update the time stamps.
3294 */
3295 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3296 return;
3297
3298 timestamp = trace_clock_local();
3299
3300 prev->ftrace_timestamp = timestamp;
3301
3302 /* only process tasks that we timestamped */
3303 if (!next->ftrace_timestamp)
3304 return;
3305
3306 /*
3307 * Update all the counters in next to make up for the
3308 * time next was sleeping.
3309 */
3310 timestamp -= next->ftrace_timestamp;
3311
3312 for (index = next->curr_ret_stack; index >= 0; index--)
3313 next->ret_stack[index].calltime += timestamp;
3314 }
3315
3316 /* Allocate a return stack for each task */
3317 static int start_graph_tracing(void)
3318 {
3319 struct ftrace_ret_stack **ret_stack_list;
3320 int ret, cpu;
3321
3322 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3323 sizeof(struct ftrace_ret_stack *),
3324 GFP_KERNEL);
3325
3326 if (!ret_stack_list)
3327 return -ENOMEM;
3328
3329 /* The cpu_boot init_task->ret_stack will never be freed */
3330 for_each_online_cpu(cpu) {
3331 if (!idle_task(cpu)->ret_stack)
3332 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
3333 }
3334
3335 do {
3336 ret = alloc_retstack_tasklist(ret_stack_list);
3337 } while (ret == -EAGAIN);
3338
3339 if (!ret) {
3340 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3341 if (ret)
3342 pr_info("ftrace_graph: Couldn't activate tracepoint"
3343 " probe to kernel_sched_switch\n");
3344 }
3345
3346 kfree(ret_stack_list);
3347 return ret;
3348 }
3349
3350 /*
3351 * Hibernation protection.
3352 * The state of the current task is too much unstable during
3353 * suspend/restore to disk. We want to protect against that.
3354 */
3355 static int
3356 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3357 void *unused)
3358 {
3359 switch (state) {
3360 case PM_HIBERNATION_PREPARE:
3361 pause_graph_tracing();
3362 break;
3363
3364 case PM_POST_HIBERNATION:
3365 unpause_graph_tracing();
3366 break;
3367 }
3368 return NOTIFY_DONE;
3369 }
3370
3371 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3372 trace_func_graph_ent_t entryfunc)
3373 {
3374 int ret = 0;
3375
3376 mutex_lock(&ftrace_lock);
3377
3378 /* we currently allow only one tracer registered at a time */
3379 if (ftrace_graph_active) {
3380 ret = -EBUSY;
3381 goto out;
3382 }
3383
3384 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3385 register_pm_notifier(&ftrace_suspend_notifier);
3386
3387 ftrace_graph_active++;
3388 ret = start_graph_tracing();
3389 if (ret) {
3390 ftrace_graph_active--;
3391 goto out;
3392 }
3393
3394 ftrace_graph_return = retfunc;
3395 ftrace_graph_entry = entryfunc;
3396
3397 ftrace_startup(FTRACE_START_FUNC_RET);
3398
3399 out:
3400 mutex_unlock(&ftrace_lock);
3401 return ret;
3402 }
3403
3404 void unregister_ftrace_graph(void)
3405 {
3406 mutex_lock(&ftrace_lock);
3407
3408 if (unlikely(!ftrace_graph_active))
3409 goto out;
3410
3411 ftrace_graph_active--;
3412 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3413 ftrace_graph_entry = ftrace_graph_entry_stub;
3414 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3415 unregister_pm_notifier(&ftrace_suspend_notifier);
3416 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
3417
3418 out:
3419 mutex_unlock(&ftrace_lock);
3420 }
3421
3422 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
3423
3424 static void
3425 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
3426 {
3427 atomic_set(&t->tracing_graph_pause, 0);
3428 atomic_set(&t->trace_overrun, 0);
3429 t->ftrace_timestamp = 0;
3430 /* make curr_ret_stack visible before we add the ret_stack */
3431 smp_wmb();
3432 t->ret_stack = ret_stack;
3433 }
3434
3435 /*
3436 * Allocate a return stack for the idle task. May be the first
3437 * time through, or it may be done by CPU hotplug online.
3438 */
3439 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
3440 {
3441 t->curr_ret_stack = -1;
3442 /*
3443 * The idle task has no parent, it either has its own
3444 * stack or no stack at all.
3445 */
3446 if (t->ret_stack)
3447 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
3448
3449 if (ftrace_graph_active) {
3450 struct ftrace_ret_stack *ret_stack;
3451
3452 ret_stack = per_cpu(idle_ret_stack, cpu);
3453 if (!ret_stack) {
3454 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3455 * sizeof(struct ftrace_ret_stack),
3456 GFP_KERNEL);
3457 if (!ret_stack)
3458 return;
3459 per_cpu(idle_ret_stack, cpu) = ret_stack;
3460 }
3461 graph_init_task(t, ret_stack);
3462 }
3463 }
3464
3465 /* Allocate a return stack for newly created task */
3466 void ftrace_graph_init_task(struct task_struct *t)
3467 {
3468 /* Make sure we do not use the parent ret_stack */
3469 t->ret_stack = NULL;
3470 t->curr_ret_stack = -1;
3471
3472 if (ftrace_graph_active) {
3473 struct ftrace_ret_stack *ret_stack;
3474
3475 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3476 * sizeof(struct ftrace_ret_stack),
3477 GFP_KERNEL);
3478 if (!ret_stack)
3479 return;
3480 graph_init_task(t, ret_stack);
3481 }
3482 }
3483
3484 void ftrace_graph_exit_task(struct task_struct *t)
3485 {
3486 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3487
3488 t->ret_stack = NULL;
3489 /* NULL must become visible to IRQs before we free it: */
3490 barrier();
3491
3492 kfree(ret_stack);
3493 }
3494
3495 void ftrace_graph_stop(void)
3496 {
3497 ftrace_stop();
3498 }
3499 #endif
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree