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Staging: hv: mousevsc: Change the allocation flags to reflect interrupt context
[zen-stable.git] / kernel / trace / ftrace.c
blobc3e4575e7829e1e807652ff2bc86fd0220d1a8a8
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/setup.h>
36
37 #include "trace_output.h"
38 #include "trace_stat.h"
39
40 #define FTRACE_WARN_ON(cond) \
41 ({ \
42 int ___r = cond; \
43 if (WARN_ON(___r)) \
44 ftrace_kill(); \
45 ___r; \
46 })
47
48 #define FTRACE_WARN_ON_ONCE(cond) \
49 ({ \
50 int ___r = cond; \
51 if (WARN_ON_ONCE(___r)) \
52 ftrace_kill(); \
53 ___r; \
54 })
55
56 /* hash bits for specific function selection */
57 #define FTRACE_HASH_BITS 7
58 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
59 #define FTRACE_HASH_DEFAULT_BITS 10
60 #define FTRACE_HASH_MAX_BITS 12
61
62 /* ftrace_enabled is a method to turn ftrace on or off */
63 int ftrace_enabled __read_mostly;
64 static int last_ftrace_enabled;
65
66 /* Quick disabling of function tracer. */
67 int function_trace_stop;
68
69 /* List for set_ftrace_pid's pids. */
70 LIST_HEAD(ftrace_pids);
71 struct ftrace_pid {
72 struct list_head list;
73 struct pid *pid;
74 };
75
76 /*
77 * ftrace_disabled is set when an anomaly is discovered.
78 * ftrace_disabled is much stronger than ftrace_enabled.
79 */
80 static int ftrace_disabled __read_mostly;
81
82 static DEFINE_MUTEX(ftrace_lock);
83
84 static struct ftrace_ops ftrace_list_end __read_mostly = {
85 .func = ftrace_stub,
86 };
87
88 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
89 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
90 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
91 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
92 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
93 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
94 static struct ftrace_ops global_ops;
95
96 static void
97 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
98
99 /*
100 * Traverse the ftrace_global_list, invoking all entries. The reason that we
101 * can use rcu_dereference_raw() is that elements removed from this list
102 * are simply leaked, so there is no need to interact with a grace-period
103 * mechanism. The rcu_dereference_raw() calls are needed to handle
104 * concurrent insertions into the ftrace_global_list.
105 *
106 * Silly Alpha and silly pointer-speculation compiler optimizations!
107 */
108 static void ftrace_global_list_func(unsigned long ip,
109 unsigned long parent_ip)
110 {
111 struct ftrace_ops *op;
112
113 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
114 return;
115
116 trace_recursion_set(TRACE_GLOBAL_BIT);
117 op = rcu_dereference_raw(ftrace_global_list); /*see above*/
118 while (op != &ftrace_list_end) {
119 op->func(ip, parent_ip);
120 op = rcu_dereference_raw(op->next); /*see above*/
121 };
122 trace_recursion_clear(TRACE_GLOBAL_BIT);
123 }
124
125 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
126 {
127 if (!test_tsk_trace_trace(current))
128 return;
129
130 ftrace_pid_function(ip, parent_ip);
131 }
132
133 static void set_ftrace_pid_function(ftrace_func_t func)
134 {
135 /* do not set ftrace_pid_function to itself! */
136 if (func != ftrace_pid_func)
137 ftrace_pid_function = func;
138 }
139
140 /**
141 * clear_ftrace_function - reset the ftrace function
142 *
143 * This NULLs the ftrace function and in essence stops
144 * tracing. There may be lag
145 */
146 void clear_ftrace_function(void)
147 {
148 ftrace_trace_function = ftrace_stub;
149 __ftrace_trace_function = ftrace_stub;
150 __ftrace_trace_function_delay = ftrace_stub;
151 ftrace_pid_function = ftrace_stub;
152 }
153
154 #undef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
155 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
156 /*
157 * For those archs that do not test ftrace_trace_stop in their
158 * mcount call site, we need to do it from C.
159 */
160 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
161 {
162 if (function_trace_stop)
163 return;
164
165 __ftrace_trace_function(ip, parent_ip);
166 }
167 #endif
168
169 static void update_global_ops(void)
170 {
171 ftrace_func_t func;
172
173 /*
174 * If there's only one function registered, then call that
175 * function directly. Otherwise, we need to iterate over the
176 * registered callers.
177 */
178 if (ftrace_global_list == &ftrace_list_end ||
179 ftrace_global_list->next == &ftrace_list_end)
180 func = ftrace_global_list->func;
181 else
182 func = ftrace_global_list_func;
183
184 /* If we filter on pids, update to use the pid function */
185 if (!list_empty(&ftrace_pids)) {
186 set_ftrace_pid_function(func);
187 func = ftrace_pid_func;
188 }
189
190 global_ops.func = func;
191 }
192
193 static void update_ftrace_function(void)
194 {
195 ftrace_func_t func;
196
197 update_global_ops();
198
199 /*
200 * If we are at the end of the list and this ops is
201 * not dynamic, then have the mcount trampoline call
202 * the function directly
203 */
204 if (ftrace_ops_list == &ftrace_list_end ||
205 (ftrace_ops_list->next == &ftrace_list_end &&
206 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
207 func = ftrace_ops_list->func;
208 else
209 func = ftrace_ops_list_func;
210
211 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
212 ftrace_trace_function = func;
213 #else
214 #ifdef CONFIG_DYNAMIC_FTRACE
215 /* do not update till all functions have been modified */
216 __ftrace_trace_function_delay = func;
217 #else
218 __ftrace_trace_function = func;
219 #endif
220 ftrace_trace_function = ftrace_test_stop_func;
221 #endif
222 }
223
224 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
225 {
226 ops->next = *list;
227 /*
228 * We are entering ops into the list but another
229 * CPU might be walking that list. We need to make sure
230 * the ops->next pointer is valid before another CPU sees
231 * the ops pointer included into the list.
232 */
233 rcu_assign_pointer(*list, ops);
234 }
235
236 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
237 {
238 struct ftrace_ops **p;
239
240 /*
241 * If we are removing the last function, then simply point
242 * to the ftrace_stub.
243 */
244 if (*list == ops && ops->next == &ftrace_list_end) {
245 *list = &ftrace_list_end;
246 return 0;
247 }
248
249 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
250 if (*p == ops)
251 break;
252
253 if (*p != ops)
254 return -1;
255
256 *p = (*p)->next;
257 return 0;
258 }
259
260 static int __register_ftrace_function(struct ftrace_ops *ops)
261 {
262 if (ftrace_disabled)
263 return -ENODEV;
264
265 if (FTRACE_WARN_ON(ops == &global_ops))
266 return -EINVAL;
267
268 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
269 return -EBUSY;
270
271 if (!core_kernel_data((unsigned long)ops))
272 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
273
274 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
275 int first = ftrace_global_list == &ftrace_list_end;
276 add_ftrace_ops(&ftrace_global_list, ops);
277 ops->flags |= FTRACE_OPS_FL_ENABLED;
278 if (first)
279 add_ftrace_ops(&ftrace_ops_list, &global_ops);
280 } else
281 add_ftrace_ops(&ftrace_ops_list, ops);
282
283 if (ftrace_enabled)
284 update_ftrace_function();
285
286 return 0;
287 }
288
289 static int __unregister_ftrace_function(struct ftrace_ops *ops)
290 {
291 int ret;
292
293 if (ftrace_disabled)
294 return -ENODEV;
295
296 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
297 return -EBUSY;
298
299 if (FTRACE_WARN_ON(ops == &global_ops))
300 return -EINVAL;
301
302 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
303 ret = remove_ftrace_ops(&ftrace_global_list, ops);
304 if (!ret && ftrace_global_list == &ftrace_list_end)
305 ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
306 if (!ret)
307 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
308 } else
309 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
310
311 if (ret < 0)
312 return ret;
313
314 if (ftrace_enabled)
315 update_ftrace_function();
316
317 /*
318 * Dynamic ops may be freed, we must make sure that all
319 * callers are done before leaving this function.
320 */
321 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
322 synchronize_sched();
323
324 return 0;
325 }
326
327 static void ftrace_update_pid_func(void)
328 {
329 /* Only do something if we are tracing something */
330 if (ftrace_trace_function == ftrace_stub)
331 return;
332
333 update_ftrace_function();
334 }
335
336 #ifdef CONFIG_FUNCTION_PROFILER
337 struct ftrace_profile {
338 struct hlist_node node;
339 unsigned long ip;
340 unsigned long counter;
341 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
342 unsigned long long time;
343 unsigned long long time_squared;
344 #endif
345 };
346
347 struct ftrace_profile_page {
348 struct ftrace_profile_page *next;
349 unsigned long index;
350 struct ftrace_profile records[];
351 };
352
353 struct ftrace_profile_stat {
354 atomic_t disabled;
355 struct hlist_head *hash;
356 struct ftrace_profile_page *pages;
357 struct ftrace_profile_page *start;
358 struct tracer_stat stat;
359 };
360
361 #define PROFILE_RECORDS_SIZE \
362 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
363
364 #define PROFILES_PER_PAGE \
365 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
366
367 static int ftrace_profile_bits __read_mostly;
368 static int ftrace_profile_enabled __read_mostly;
369
370 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
371 static DEFINE_MUTEX(ftrace_profile_lock);
372
373 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
374
375 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
376
377 static void *
378 function_stat_next(void *v, int idx)
379 {
380 struct ftrace_profile *rec = v;
381 struct ftrace_profile_page *pg;
382
383 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
384
385 again:
386 if (idx != 0)
387 rec++;
388
389 if ((void *)rec >= (void *)&pg->records[pg->index]) {
390 pg = pg->next;
391 if (!pg)
392 return NULL;
393 rec = &pg->records[0];
394 if (!rec->counter)
395 goto again;
396 }
397
398 return rec;
399 }
400
401 static void *function_stat_start(struct tracer_stat *trace)
402 {
403 struct ftrace_profile_stat *stat =
404 container_of(trace, struct ftrace_profile_stat, stat);
405
406 if (!stat || !stat->start)
407 return NULL;
408
409 return function_stat_next(&stat->start->records[0], 0);
410 }
411
412 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
413 /* function graph compares on total time */
414 static int function_stat_cmp(void *p1, void *p2)
415 {
416 struct ftrace_profile *a = p1;
417 struct ftrace_profile *b = p2;
418
419 if (a->time < b->time)
420 return -1;
421 if (a->time > b->time)
422 return 1;
423 else
424 return 0;
425 }
426 #else
427 /* not function graph compares against hits */
428 static int function_stat_cmp(void *p1, void *p2)
429 {
430 struct ftrace_profile *a = p1;
431 struct ftrace_profile *b = p2;
432
433 if (a->counter < b->counter)
434 return -1;
435 if (a->counter > b->counter)
436 return 1;
437 else
438 return 0;
439 }
440 #endif
441
442 static int function_stat_headers(struct seq_file *m)
443 {
444 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
445 seq_printf(m, " Function "
446 "Hit Time Avg s^2\n"
447 " -------- "
448 "--- ---- --- ---\n");
449 #else
450 seq_printf(m, " Function Hit\n"
451 " -------- ---\n");
452 #endif
453 return 0;
454 }
455
456 static int function_stat_show(struct seq_file *m, void *v)
457 {
458 struct ftrace_profile *rec = v;
459 char str[KSYM_SYMBOL_LEN];
460 int ret = 0;
461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
462 static struct trace_seq s;
463 unsigned long long avg;
464 unsigned long long stddev;
465 #endif
466 mutex_lock(&ftrace_profile_lock);
467
468 /* we raced with function_profile_reset() */
469 if (unlikely(rec->counter == 0)) {
470 ret = -EBUSY;
471 goto out;
472 }
473
474 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
475 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
476
477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
478 seq_printf(m, " ");
479 avg = rec->time;
480 do_div(avg, rec->counter);
481
482 /* Sample standard deviation (s^2) */
483 if (rec->counter <= 1)
484 stddev = 0;
485 else {
486 stddev = rec->time_squared - rec->counter * avg * avg;
487 /*
488 * Divide only 1000 for ns^2 -> us^2 conversion.
489 * trace_print_graph_duration will divide 1000 again.
490 */
491 do_div(stddev, (rec->counter - 1) * 1000);
492 }
493
494 trace_seq_init(&s);
495 trace_print_graph_duration(rec->time, &s);
496 trace_seq_puts(&s, " ");
497 trace_print_graph_duration(avg, &s);
498 trace_seq_puts(&s, " ");
499 trace_print_graph_duration(stddev, &s);
500 trace_print_seq(m, &s);
501 #endif
502 seq_putc(m, '\n');
503 out:
504 mutex_unlock(&ftrace_profile_lock);
505
506 return ret;
507 }
508
509 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
510 {
511 struct ftrace_profile_page *pg;
512
513 pg = stat->pages = stat->start;
514
515 while (pg) {
516 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
517 pg->index = 0;
518 pg = pg->next;
519 }
520
521 memset(stat->hash, 0,
522 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
523 }
524
525 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
526 {
527 struct ftrace_profile_page *pg;
528 int functions;
529 int pages;
530 int i;
531
532 /* If we already allocated, do nothing */
533 if (stat->pages)
534 return 0;
535
536 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
537 if (!stat->pages)
538 return -ENOMEM;
539
540 #ifdef CONFIG_DYNAMIC_FTRACE
541 functions = ftrace_update_tot_cnt;
542 #else
543 /*
544 * We do not know the number of functions that exist because
545 * dynamic tracing is what counts them. With past experience
546 * we have around 20K functions. That should be more than enough.
547 * It is highly unlikely we will execute every function in
548 * the kernel.
549 */
550 functions = 20000;
551 #endif
552
553 pg = stat->start = stat->pages;
554
555 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
556
557 for (i = 0; i < pages; i++) {
558 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
559 if (!pg->next)
560 goto out_free;
561 pg = pg->next;
562 }
563
564 return 0;
565
566 out_free:
567 pg = stat->start;
568 while (pg) {
569 unsigned long tmp = (unsigned long)pg;
570
571 pg = pg->next;
572 free_page(tmp);
573 }
574
575 free_page((unsigned long)stat->pages);
576 stat->pages = NULL;
577 stat->start = NULL;
578
579 return -ENOMEM;
580 }
581
582 static int ftrace_profile_init_cpu(int cpu)
583 {
584 struct ftrace_profile_stat *stat;
585 int size;
586
587 stat = &per_cpu(ftrace_profile_stats, cpu);
588
589 if (stat->hash) {
590 /* If the profile is already created, simply reset it */
591 ftrace_profile_reset(stat);
592 return 0;
593 }
594
595 /*
596 * We are profiling all functions, but usually only a few thousand
597 * functions are hit. We'll make a hash of 1024 items.
598 */
599 size = FTRACE_PROFILE_HASH_SIZE;
600
601 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
602
603 if (!stat->hash)
604 return -ENOMEM;
605
606 if (!ftrace_profile_bits) {
607 size--;
608
609 for (; size; size >>= 1)
610 ftrace_profile_bits++;
611 }
612
613 /* Preallocate the function profiling pages */
614 if (ftrace_profile_pages_init(stat) < 0) {
615 kfree(stat->hash);
616 stat->hash = NULL;
617 return -ENOMEM;
618 }
619
620 return 0;
621 }
622
623 static int ftrace_profile_init(void)
624 {
625 int cpu;
626 int ret = 0;
627
628 for_each_online_cpu(cpu) {
629 ret = ftrace_profile_init_cpu(cpu);
630 if (ret)
631 break;
632 }
633
634 return ret;
635 }
636
637 /* interrupts must be disabled */
638 static struct ftrace_profile *
639 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
640 {
641 struct ftrace_profile *rec;
642 struct hlist_head *hhd;
643 struct hlist_node *n;
644 unsigned long key;
645
646 key = hash_long(ip, ftrace_profile_bits);
647 hhd = &stat->hash[key];
648
649 if (hlist_empty(hhd))
650 return NULL;
651
652 hlist_for_each_entry_rcu(rec, n, hhd, node) {
653 if (rec->ip == ip)
654 return rec;
655 }
656
657 return NULL;
658 }
659
660 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
661 struct ftrace_profile *rec)
662 {
663 unsigned long key;
664
665 key = hash_long(rec->ip, ftrace_profile_bits);
666 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
667 }
668
669 /*
670 * The memory is already allocated, this simply finds a new record to use.
671 */
672 static struct ftrace_profile *
673 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
674 {
675 struct ftrace_profile *rec = NULL;
676
677 /* prevent recursion (from NMIs) */
678 if (atomic_inc_return(&stat->disabled) != 1)
679 goto out;
680
681 /*
682 * Try to find the function again since an NMI
683 * could have added it
684 */
685 rec = ftrace_find_profiled_func(stat, ip);
686 if (rec)
687 goto out;
688
689 if (stat->pages->index == PROFILES_PER_PAGE) {
690 if (!stat->pages->next)
691 goto out;
692 stat->pages = stat->pages->next;
693 }
694
695 rec = &stat->pages->records[stat->pages->index++];
696 rec->ip = ip;
697 ftrace_add_profile(stat, rec);
698
699 out:
700 atomic_dec(&stat->disabled);
701
702 return rec;
703 }
704
705 static void
706 function_profile_call(unsigned long ip, unsigned long parent_ip)
707 {
708 struct ftrace_profile_stat *stat;
709 struct ftrace_profile *rec;
710 unsigned long flags;
711
712 if (!ftrace_profile_enabled)
713 return;
714
715 local_irq_save(flags);
716
717 stat = &__get_cpu_var(ftrace_profile_stats);
718 if (!stat->hash || !ftrace_profile_enabled)
719 goto out;
720
721 rec = ftrace_find_profiled_func(stat, ip);
722 if (!rec) {
723 rec = ftrace_profile_alloc(stat, ip);
724 if (!rec)
725 goto out;
726 }
727
728 rec->counter++;
729 out:
730 local_irq_restore(flags);
731 }
732
733 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
734 static int profile_graph_entry(struct ftrace_graph_ent *trace)
735 {
736 function_profile_call(trace->func, 0);
737 return 1;
738 }
739
740 static void profile_graph_return(struct ftrace_graph_ret *trace)
741 {
742 struct ftrace_profile_stat *stat;
743 unsigned long long calltime;
744 struct ftrace_profile *rec;
745 unsigned long flags;
746
747 local_irq_save(flags);
748 stat = &__get_cpu_var(ftrace_profile_stats);
749 if (!stat->hash || !ftrace_profile_enabled)
750 goto out;
751
752 /* If the calltime was zero'd ignore it */
753 if (!trace->calltime)
754 goto out;
755
756 calltime = trace->rettime - trace->calltime;
757
758 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
759 int index;
760
761 index = trace->depth;
762
763 /* Append this call time to the parent time to subtract */
764 if (index)
765 current->ret_stack[index - 1].subtime += calltime;
766
767 if (current->ret_stack[index].subtime < calltime)
768 calltime -= current->ret_stack[index].subtime;
769 else
770 calltime = 0;
771 }
772
773 rec = ftrace_find_profiled_func(stat, trace->func);
774 if (rec) {
775 rec->time += calltime;
776 rec->time_squared += calltime * calltime;
777 }
778
779 out:
780 local_irq_restore(flags);
781 }
782
783 static int register_ftrace_profiler(void)
784 {
785 return register_ftrace_graph(&profile_graph_return,
786 &profile_graph_entry);
787 }
788
789 static void unregister_ftrace_profiler(void)
790 {
791 unregister_ftrace_graph();
792 }
793 #else
794 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
795 .func = function_profile_call,
796 };
797
798 static int register_ftrace_profiler(void)
799 {
800 return register_ftrace_function(&ftrace_profile_ops);
801 }
802
803 static void unregister_ftrace_profiler(void)
804 {
805 unregister_ftrace_function(&ftrace_profile_ops);
806 }
807 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
808
809 static ssize_t
810 ftrace_profile_write(struct file *filp, const char __user *ubuf,
811 size_t cnt, loff_t *ppos)
812 {
813 unsigned long val;
814 int ret;
815
816 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
817 if (ret)
818 return ret;
819
820 val = !!val;
821
822 mutex_lock(&ftrace_profile_lock);
823 if (ftrace_profile_enabled ^ val) {
824 if (val) {
825 ret = ftrace_profile_init();
826 if (ret < 0) {
827 cnt = ret;
828 goto out;
829 }
830
831 ret = register_ftrace_profiler();
832 if (ret < 0) {
833 cnt = ret;
834 goto out;
835 }
836 ftrace_profile_enabled = 1;
837 } else {
838 ftrace_profile_enabled = 0;
839 /*
840 * unregister_ftrace_profiler calls stop_machine
841 * so this acts like an synchronize_sched.
842 */
843 unregister_ftrace_profiler();
844 }
845 }
846 out:
847 mutex_unlock(&ftrace_profile_lock);
848
849 *ppos += cnt;
850
851 return cnt;
852 }
853
854 static ssize_t
855 ftrace_profile_read(struct file *filp, char __user *ubuf,
856 size_t cnt, loff_t *ppos)
857 {
858 char buf[64]; /* big enough to hold a number */
859 int r;
860
861 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
862 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
863 }
864
865 static const struct file_operations ftrace_profile_fops = {
866 .open = tracing_open_generic,
867 .read = ftrace_profile_read,
868 .write = ftrace_profile_write,
869 .llseek = default_llseek,
870 };
871
872 /* used to initialize the real stat files */
873 static struct tracer_stat function_stats __initdata = {
874 .name = "functions",
875 .stat_start = function_stat_start,
876 .stat_next = function_stat_next,
877 .stat_cmp = function_stat_cmp,
878 .stat_headers = function_stat_headers,
879 .stat_show = function_stat_show
880 };
881
882 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
883 {
884 struct ftrace_profile_stat *stat;
885 struct dentry *entry;
886 char *name;
887 int ret;
888 int cpu;
889
890 for_each_possible_cpu(cpu) {
891 stat = &per_cpu(ftrace_profile_stats, cpu);
892
893 /* allocate enough for function name + cpu number */
894 name = kmalloc(32, GFP_KERNEL);
895 if (!name) {
896 /*
897 * The files created are permanent, if something happens
898 * we still do not free memory.
899 */
900 WARN(1,
901 "Could not allocate stat file for cpu %d\n",
902 cpu);
903 return;
904 }
905 stat->stat = function_stats;
906 snprintf(name, 32, "function%d", cpu);
907 stat->stat.name = name;
908 ret = register_stat_tracer(&stat->stat);
909 if (ret) {
910 WARN(1,
911 "Could not register function stat for cpu %d\n",
912 cpu);
913 kfree(name);
914 return;
915 }
916 }
917
918 entry = debugfs_create_file("function_profile_enabled", 0644,
919 d_tracer, NULL, &ftrace_profile_fops);
920 if (!entry)
921 pr_warning("Could not create debugfs "
922 "'function_profile_enabled' entry\n");
923 }
924
925 #else /* CONFIG_FUNCTION_PROFILER */
926 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
927 {
928 }
929 #endif /* CONFIG_FUNCTION_PROFILER */
930
931 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
932
933 #ifdef CONFIG_DYNAMIC_FTRACE
934
935 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
936 # error Dynamic ftrace depends on MCOUNT_RECORD
937 #endif
938
939 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
940
941 struct ftrace_func_probe {
942 struct hlist_node node;
943 struct ftrace_probe_ops *ops;
944 unsigned long flags;
945 unsigned long ip;
946 void *data;
947 struct rcu_head rcu;
948 };
949
950 enum {
951 FTRACE_ENABLE_CALLS = (1 << 0),
952 FTRACE_DISABLE_CALLS = (1 << 1),
953 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
954 FTRACE_START_FUNC_RET = (1 << 3),
955 FTRACE_STOP_FUNC_RET = (1 << 4),
956 };
957 struct ftrace_func_entry {
958 struct hlist_node hlist;
959 unsigned long ip;
960 };
961
962 struct ftrace_hash {
963 unsigned long size_bits;
964 struct hlist_head *buckets;
965 unsigned long count;
966 struct rcu_head rcu;
967 };
968
969 /*
970 * We make these constant because no one should touch them,
971 * but they are used as the default "empty hash", to avoid allocating
972 * it all the time. These are in a read only section such that if
973 * anyone does try to modify it, it will cause an exception.
974 */
975 static const struct hlist_head empty_buckets[1];
976 static const struct ftrace_hash empty_hash = {
977 .buckets = (struct hlist_head *)empty_buckets,
978 };
979 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
980
981 static struct ftrace_ops global_ops = {
982 .func = ftrace_stub,
983 .notrace_hash = EMPTY_HASH,
984 .filter_hash = EMPTY_HASH,
985 };
986
987 static struct dyn_ftrace *ftrace_new_addrs;
988
989 static DEFINE_MUTEX(ftrace_regex_lock);
990
991 struct ftrace_page {
992 struct ftrace_page *next;
993 int index;
994 struct dyn_ftrace records[];
995 };
996
997 #define ENTRIES_PER_PAGE \
998 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
999
1000 /* estimate from running different kernels */
1001 #define NR_TO_INIT 10000
1002
1003 static struct ftrace_page *ftrace_pages_start;
1004 static struct ftrace_page *ftrace_pages;
1005
1006 static struct dyn_ftrace *ftrace_free_records;
1007
1008 static struct ftrace_func_entry *
1009 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1010 {
1011 unsigned long key;
1012 struct ftrace_func_entry *entry;
1013 struct hlist_head *hhd;
1014 struct hlist_node *n;
1015
1016 if (!hash->count)
1017 return NULL;
1018
1019 if (hash->size_bits > 0)
1020 key = hash_long(ip, hash->size_bits);
1021 else
1022 key = 0;
1023
1024 hhd = &hash->buckets[key];
1025
1026 hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1027 if (entry->ip == ip)
1028 return entry;
1029 }
1030 return NULL;
1031 }
1032
1033 static void __add_hash_entry(struct ftrace_hash *hash,
1034 struct ftrace_func_entry *entry)
1035 {
1036 struct hlist_head *hhd;
1037 unsigned long key;
1038
1039 if (hash->size_bits)
1040 key = hash_long(entry->ip, hash->size_bits);
1041 else
1042 key = 0;
1043
1044 hhd = &hash->buckets[key];
1045 hlist_add_head(&entry->hlist, hhd);
1046 hash->count++;
1047 }
1048
1049 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1050 {
1051 struct ftrace_func_entry *entry;
1052
1053 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1054 if (!entry)
1055 return -ENOMEM;
1056
1057 entry->ip = ip;
1058 __add_hash_entry(hash, entry);
1059
1060 return 0;
1061 }
1062
1063 static void
1064 free_hash_entry(struct ftrace_hash *hash,
1065 struct ftrace_func_entry *entry)
1066 {
1067 hlist_del(&entry->hlist);
1068 kfree(entry);
1069 hash->count--;
1070 }
1071
1072 static void
1073 remove_hash_entry(struct ftrace_hash *hash,
1074 struct ftrace_func_entry *entry)
1075 {
1076 hlist_del(&entry->hlist);
1077 hash->count--;
1078 }
1079
1080 static void ftrace_hash_clear(struct ftrace_hash *hash)
1081 {
1082 struct hlist_head *hhd;
1083 struct hlist_node *tp, *tn;
1084 struct ftrace_func_entry *entry;
1085 int size = 1 << hash->size_bits;
1086 int i;
1087
1088 if (!hash->count)
1089 return;
1090
1091 for (i = 0; i < size; i++) {
1092 hhd = &hash->buckets[i];
1093 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1094 free_hash_entry(hash, entry);
1095 }
1096 FTRACE_WARN_ON(hash->count);
1097 }
1098
1099 static void free_ftrace_hash(struct ftrace_hash *hash)
1100 {
1101 if (!hash || hash == EMPTY_HASH)
1102 return;
1103 ftrace_hash_clear(hash);
1104 kfree(hash->buckets);
1105 kfree(hash);
1106 }
1107
1108 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1109 {
1110 struct ftrace_hash *hash;
1111
1112 hash = container_of(rcu, struct ftrace_hash, rcu);
1113 free_ftrace_hash(hash);
1114 }
1115
1116 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1117 {
1118 if (!hash || hash == EMPTY_HASH)
1119 return;
1120 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1121 }
1122
1123 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1124 {
1125 struct ftrace_hash *hash;
1126 int size;
1127
1128 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1129 if (!hash)
1130 return NULL;
1131
1132 size = 1 << size_bits;
1133 hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1134
1135 if (!hash->buckets) {
1136 kfree(hash);
1137 return NULL;
1138 }
1139
1140 hash->size_bits = size_bits;
1141
1142 return hash;
1143 }
1144
1145 static struct ftrace_hash *
1146 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1147 {
1148 struct ftrace_func_entry *entry;
1149 struct ftrace_hash *new_hash;
1150 struct hlist_node *tp;
1151 int size;
1152 int ret;
1153 int i;
1154
1155 new_hash = alloc_ftrace_hash(size_bits);
1156 if (!new_hash)
1157 return NULL;
1158
1159 /* Empty hash? */
1160 if (!hash || !hash->count)
1161 return new_hash;
1162
1163 size = 1 << hash->size_bits;
1164 for (i = 0; i < size; i++) {
1165 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1166 ret = add_hash_entry(new_hash, entry->ip);
1167 if (ret < 0)
1168 goto free_hash;
1169 }
1170 }
1171
1172 FTRACE_WARN_ON(new_hash->count != hash->count);
1173
1174 return new_hash;
1175
1176 free_hash:
1177 free_ftrace_hash(new_hash);
1178 return NULL;
1179 }
1180
1181 static void
1182 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1183 static void
1184 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1185
1186 static int
1187 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1188 struct ftrace_hash **dst, struct ftrace_hash *src)
1189 {
1190 struct ftrace_func_entry *entry;
1191 struct hlist_node *tp, *tn;
1192 struct hlist_head *hhd;
1193 struct ftrace_hash *old_hash;
1194 struct ftrace_hash *new_hash;
1195 unsigned long key;
1196 int size = src->count;
1197 int bits = 0;
1198 int ret;
1199 int i;
1200
1201 /*
1202 * Remove the current set, update the hash and add
1203 * them back.
1204 */
1205 ftrace_hash_rec_disable(ops, enable);
1206
1207 /*
1208 * If the new source is empty, just free dst and assign it
1209 * the empty_hash.
1210 */
1211 if (!src->count) {
1212 free_ftrace_hash_rcu(*dst);
1213 rcu_assign_pointer(*dst, EMPTY_HASH);
1214 return 0;
1215 }
1216
1217 /*
1218 * Make the hash size about 1/2 the # found
1219 */
1220 for (size /= 2; size; size >>= 1)
1221 bits++;
1222
1223 /* Don't allocate too much */
1224 if (bits > FTRACE_HASH_MAX_BITS)
1225 bits = FTRACE_HASH_MAX_BITS;
1226
1227 ret = -ENOMEM;
1228 new_hash = alloc_ftrace_hash(bits);
1229 if (!new_hash)
1230 goto out;
1231
1232 size = 1 << src->size_bits;
1233 for (i = 0; i < size; i++) {
1234 hhd = &src->buckets[i];
1235 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1236 if (bits > 0)
1237 key = hash_long(entry->ip, bits);
1238 else
1239 key = 0;
1240 remove_hash_entry(src, entry);
1241 __add_hash_entry(new_hash, entry);
1242 }
1243 }
1244
1245 old_hash = *dst;
1246 rcu_assign_pointer(*dst, new_hash);
1247 free_ftrace_hash_rcu(old_hash);
1248
1249 ret = 0;
1250 out:
1251 /*
1252 * Enable regardless of ret:
1253 * On success, we enable the new hash.
1254 * On failure, we re-enable the original hash.
1255 */
1256 ftrace_hash_rec_enable(ops, enable);
1257
1258 return ret;
1259 }
1260
1261 /*
1262 * Test the hashes for this ops to see if we want to call
1263 * the ops->func or not.
1264 *
1265 * It's a match if the ip is in the ops->filter_hash or
1266 * the filter_hash does not exist or is empty,
1267 * AND
1268 * the ip is not in the ops->notrace_hash.
1269 *
1270 * This needs to be called with preemption disabled as
1271 * the hashes are freed with call_rcu_sched().
1272 */
1273 static int
1274 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1275 {
1276 struct ftrace_hash *filter_hash;
1277 struct ftrace_hash *notrace_hash;
1278 int ret;
1279
1280 filter_hash = rcu_dereference_raw(ops->filter_hash);
1281 notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1282
1283 if ((!filter_hash || !filter_hash->count ||
1284 ftrace_lookup_ip(filter_hash, ip)) &&
1285 (!notrace_hash || !notrace_hash->count ||
1286 !ftrace_lookup_ip(notrace_hash, ip)))
1287 ret = 1;
1288 else
1289 ret = 0;
1290
1291 return ret;
1292 }
1293
1294 /*
1295 * This is a double for. Do not use 'break' to break out of the loop,
1296 * you must use a goto.
1297 */
1298 #define do_for_each_ftrace_rec(pg, rec) \
1299 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1300 int _____i; \
1301 for (_____i = 0; _____i < pg->index; _____i++) { \
1302 rec = &pg->records[_____i];
1303
1304 #define while_for_each_ftrace_rec() \
1305 } \
1306 }
1307
1308 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1309 int filter_hash,
1310 bool inc)
1311 {
1312 struct ftrace_hash *hash;
1313 struct ftrace_hash *other_hash;
1314 struct ftrace_page *pg;
1315 struct dyn_ftrace *rec;
1316 int count = 0;
1317 int all = 0;
1318
1319 /* Only update if the ops has been registered */
1320 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1321 return;
1322
1323 /*
1324 * In the filter_hash case:
1325 * If the count is zero, we update all records.
1326 * Otherwise we just update the items in the hash.
1327 *
1328 * In the notrace_hash case:
1329 * We enable the update in the hash.
1330 * As disabling notrace means enabling the tracing,
1331 * and enabling notrace means disabling, the inc variable
1332 * gets inversed.
1333 */
1334 if (filter_hash) {
1335 hash = ops->filter_hash;
1336 other_hash = ops->notrace_hash;
1337 if (!hash || !hash->count)
1338 all = 1;
1339 } else {
1340 inc = !inc;
1341 hash = ops->notrace_hash;
1342 other_hash = ops->filter_hash;
1343 /*
1344 * If the notrace hash has no items,
1345 * then there's nothing to do.
1346 */
1347 if (hash && !hash->count)
1348 return;
1349 }
1350
1351 do_for_each_ftrace_rec(pg, rec) {
1352 int in_other_hash = 0;
1353 int in_hash = 0;
1354 int match = 0;
1355
1356 if (all) {
1357 /*
1358 * Only the filter_hash affects all records.
1359 * Update if the record is not in the notrace hash.
1360 */
1361 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1362 match = 1;
1363 } else {
1364 in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1365 in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1366
1367 /*
1368 *
1369 */
1370 if (filter_hash && in_hash && !in_other_hash)
1371 match = 1;
1372 else if (!filter_hash && in_hash &&
1373 (in_other_hash || !other_hash->count))
1374 match = 1;
1375 }
1376 if (!match)
1377 continue;
1378
1379 if (inc) {
1380 rec->flags++;
1381 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1382 return;
1383 } else {
1384 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1385 return;
1386 rec->flags--;
1387 }
1388 count++;
1389 /* Shortcut, if we handled all records, we are done. */
1390 if (!all && count == hash->count)
1391 return;
1392 } while_for_each_ftrace_rec();
1393 }
1394
1395 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1396 int filter_hash)
1397 {
1398 __ftrace_hash_rec_update(ops, filter_hash, 0);
1399 }
1400
1401 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1402 int filter_hash)
1403 {
1404 __ftrace_hash_rec_update(ops, filter_hash, 1);
1405 }
1406
1407 static void ftrace_free_rec(struct dyn_ftrace *rec)
1408 {
1409 rec->freelist = ftrace_free_records;
1410 ftrace_free_records = rec;
1411 rec->flags |= FTRACE_FL_FREE;
1412 }
1413
1414 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1415 {
1416 struct dyn_ftrace *rec;
1417
1418 /* First check for freed records */
1419 if (ftrace_free_records) {
1420 rec = ftrace_free_records;
1421
1422 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
1423 FTRACE_WARN_ON_ONCE(1);
1424 ftrace_free_records = NULL;
1425 return NULL;
1426 }
1427
1428 ftrace_free_records = rec->freelist;
1429 memset(rec, 0, sizeof(*rec));
1430 return rec;
1431 }
1432
1433 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
1434 if (!ftrace_pages->next) {
1435 /* allocate another page */
1436 ftrace_pages->next =
1437 (void *)get_zeroed_page(GFP_KERNEL);
1438 if (!ftrace_pages->next)
1439 return NULL;
1440 }
1441 ftrace_pages = ftrace_pages->next;
1442 }
1443
1444 return &ftrace_pages->records[ftrace_pages->index++];
1445 }
1446
1447 static struct dyn_ftrace *
1448 ftrace_record_ip(unsigned long ip)
1449 {
1450 struct dyn_ftrace *rec;
1451
1452 if (ftrace_disabled)
1453 return NULL;
1454
1455 rec = ftrace_alloc_dyn_node(ip);
1456 if (!rec)
1457 return NULL;
1458
1459 rec->ip = ip;
1460 rec->newlist = ftrace_new_addrs;
1461 ftrace_new_addrs = rec;
1462
1463 return rec;
1464 }
1465
1466 static void print_ip_ins(const char *fmt, unsigned char *p)
1467 {
1468 int i;
1469
1470 printk(KERN_CONT "%s", fmt);
1471
1472 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1473 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1474 }
1475
1476 static void ftrace_bug(int failed, unsigned long ip)
1477 {
1478 switch (failed) {
1479 case -EFAULT:
1480 FTRACE_WARN_ON_ONCE(1);
1481 pr_info("ftrace faulted on modifying ");
1482 print_ip_sym(ip);
1483 break;
1484 case -EINVAL:
1485 FTRACE_WARN_ON_ONCE(1);
1486 pr_info("ftrace failed to modify ");
1487 print_ip_sym(ip);
1488 print_ip_ins(" actual: ", (unsigned char *)ip);
1489 printk(KERN_CONT "\n");
1490 break;
1491 case -EPERM:
1492 FTRACE_WARN_ON_ONCE(1);
1493 pr_info("ftrace faulted on writing ");
1494 print_ip_sym(ip);
1495 break;
1496 default:
1497 FTRACE_WARN_ON_ONCE(1);
1498 pr_info("ftrace faulted on unknown error ");
1499 print_ip_sym(ip);
1500 }
1501 }
1502
1503
1504 /* Return 1 if the address range is reserved for ftrace */
1505 int ftrace_text_reserved(void *start, void *end)
1506 {
1507 struct dyn_ftrace *rec;
1508 struct ftrace_page *pg;
1509
1510 do_for_each_ftrace_rec(pg, rec) {
1511 if (rec->ip <= (unsigned long)end &&
1512 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1513 return 1;
1514 } while_for_each_ftrace_rec();
1515 return 0;
1516 }
1517
1518
1519 static int
1520 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1521 {
1522 unsigned long ftrace_addr;
1523 unsigned long flag = 0UL;
1524
1525 ftrace_addr = (unsigned long)FTRACE_ADDR;
1526
1527 /*
1528 * If we are enabling tracing:
1529 *
1530 * If the record has a ref count, then we need to enable it
1531 * because someone is using it.
1532 *
1533 * Otherwise we make sure its disabled.
1534 *
1535 * If we are disabling tracing, then disable all records that
1536 * are enabled.
1537 */
1538 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1539 flag = FTRACE_FL_ENABLED;
1540
1541 /* If the state of this record hasn't changed, then do nothing */
1542 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1543 return 0;
1544
1545 if (flag) {
1546 rec->flags |= FTRACE_FL_ENABLED;
1547 return ftrace_make_call(rec, ftrace_addr);
1548 }
1549
1550 rec->flags &= ~FTRACE_FL_ENABLED;
1551 return ftrace_make_nop(NULL, rec, ftrace_addr);
1552 }
1553
1554 static void ftrace_replace_code(int enable)
1555 {
1556 struct dyn_ftrace *rec;
1557 struct ftrace_page *pg;
1558 int failed;
1559
1560 if (unlikely(ftrace_disabled))
1561 return;
1562
1563 do_for_each_ftrace_rec(pg, rec) {
1564 /* Skip over free records */
1565 if (rec->flags & FTRACE_FL_FREE)
1566 continue;
1567
1568 failed = __ftrace_replace_code(rec, enable);
1569 if (failed) {
1570 ftrace_bug(failed, rec->ip);
1571 /* Stop processing */
1572 return;
1573 }
1574 } while_for_each_ftrace_rec();
1575 }
1576
1577 static int
1578 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1579 {
1580 unsigned long ip;
1581 int ret;
1582
1583 ip = rec->ip;
1584
1585 if (unlikely(ftrace_disabled))
1586 return 0;
1587
1588 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1589 if (ret) {
1590 ftrace_bug(ret, ip);
1591 return 0;
1592 }
1593 return 1;
1594 }
1595
1596 /*
1597 * archs can override this function if they must do something
1598 * before the modifying code is performed.
1599 */
1600 int __weak ftrace_arch_code_modify_prepare(void)
1601 {
1602 return 0;
1603 }
1604
1605 /*
1606 * archs can override this function if they must do something
1607 * after the modifying code is performed.
1608 */
1609 int __weak ftrace_arch_code_modify_post_process(void)
1610 {
1611 return 0;
1612 }
1613
1614 static int __ftrace_modify_code(void *data)
1615 {
1616 int *command = data;
1617
1618 /*
1619 * Do not call function tracer while we update the code.
1620 * We are in stop machine, no worrying about races.
1621 */
1622 function_trace_stop++;
1623
1624 if (*command & FTRACE_ENABLE_CALLS)
1625 ftrace_replace_code(1);
1626 else if (*command & FTRACE_DISABLE_CALLS)
1627 ftrace_replace_code(0);
1628
1629 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1630 ftrace_update_ftrace_func(ftrace_trace_function);
1631
1632 if (*command & FTRACE_START_FUNC_RET)
1633 ftrace_enable_ftrace_graph_caller();
1634 else if (*command & FTRACE_STOP_FUNC_RET)
1635 ftrace_disable_ftrace_graph_caller();
1636
1637 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1638 /*
1639 * For archs that call ftrace_test_stop_func(), we must
1640 * wait till after we update all the function callers
1641 * before we update the callback. This keeps different
1642 * ops that record different functions from corrupting
1643 * each other.
1644 */
1645 __ftrace_trace_function = __ftrace_trace_function_delay;
1646 #endif
1647 function_trace_stop--;
1648
1649 return 0;
1650 }
1651
1652 static void ftrace_run_update_code(int command)
1653 {
1654 int ret;
1655
1656 ret = ftrace_arch_code_modify_prepare();
1657 FTRACE_WARN_ON(ret);
1658 if (ret)
1659 return;
1660
1661 stop_machine(__ftrace_modify_code, &command, NULL);
1662
1663 ret = ftrace_arch_code_modify_post_process();
1664 FTRACE_WARN_ON(ret);
1665 }
1666
1667 static ftrace_func_t saved_ftrace_func;
1668 static int ftrace_start_up;
1669 static int global_start_up;
1670
1671 static void ftrace_startup_enable(int command)
1672 {
1673 if (saved_ftrace_func != ftrace_trace_function) {
1674 saved_ftrace_func = ftrace_trace_function;
1675 command |= FTRACE_UPDATE_TRACE_FUNC;
1676 }
1677
1678 if (!command || !ftrace_enabled)
1679 return;
1680
1681 ftrace_run_update_code(command);
1682 }
1683
1684 static int ftrace_startup(struct ftrace_ops *ops, int command)
1685 {
1686 bool hash_enable = true;
1687
1688 if (unlikely(ftrace_disabled))
1689 return -ENODEV;
1690
1691 ftrace_start_up++;
1692 command |= FTRACE_ENABLE_CALLS;
1693
1694 /* ops marked global share the filter hashes */
1695 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1696 ops = &global_ops;
1697 /* Don't update hash if global is already set */
1698 if (global_start_up)
1699 hash_enable = false;
1700 global_start_up++;
1701 }
1702
1703 ops->flags |= FTRACE_OPS_FL_ENABLED;
1704 if (hash_enable)
1705 ftrace_hash_rec_enable(ops, 1);
1706
1707 ftrace_startup_enable(command);
1708
1709 return 0;
1710 }
1711
1712 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1713 {
1714 bool hash_disable = true;
1715
1716 if (unlikely(ftrace_disabled))
1717 return;
1718
1719 ftrace_start_up--;
1720 /*
1721 * Just warn in case of unbalance, no need to kill ftrace, it's not
1722 * critical but the ftrace_call callers may be never nopped again after
1723 * further ftrace uses.
1724 */
1725 WARN_ON_ONCE(ftrace_start_up < 0);
1726
1727 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1728 ops = &global_ops;
1729 global_start_up--;
1730 WARN_ON_ONCE(global_start_up < 0);
1731 /* Don't update hash if global still has users */
1732 if (global_start_up) {
1733 WARN_ON_ONCE(!ftrace_start_up);
1734 hash_disable = false;
1735 }
1736 }
1737
1738 if (hash_disable)
1739 ftrace_hash_rec_disable(ops, 1);
1740
1741 if (ops != &global_ops || !global_start_up)
1742 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1743
1744 if (!ftrace_start_up)
1745 command |= FTRACE_DISABLE_CALLS;
1746
1747 if (saved_ftrace_func != ftrace_trace_function) {
1748 saved_ftrace_func = ftrace_trace_function;
1749 command |= FTRACE_UPDATE_TRACE_FUNC;
1750 }
1751
1752 if (!command || !ftrace_enabled)
1753 return;
1754
1755 ftrace_run_update_code(command);
1756 }
1757
1758 static void ftrace_startup_sysctl(void)
1759 {
1760 if (unlikely(ftrace_disabled))
1761 return;
1762
1763 /* Force update next time */
1764 saved_ftrace_func = NULL;
1765 /* ftrace_start_up is true if we want ftrace running */
1766 if (ftrace_start_up)
1767 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1768 }
1769
1770 static void ftrace_shutdown_sysctl(void)
1771 {
1772 if (unlikely(ftrace_disabled))
1773 return;
1774
1775 /* ftrace_start_up is true if ftrace is running */
1776 if (ftrace_start_up)
1777 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1778 }
1779
1780 static cycle_t ftrace_update_time;
1781 static unsigned long ftrace_update_cnt;
1782 unsigned long ftrace_update_tot_cnt;
1783
1784 static int ops_traces_mod(struct ftrace_ops *ops)
1785 {
1786 struct ftrace_hash *hash;
1787
1788 hash = ops->filter_hash;
1789 return !!(!hash || !hash->count);
1790 }
1791
1792 static int ftrace_update_code(struct module *mod)
1793 {
1794 struct dyn_ftrace *p;
1795 cycle_t start, stop;
1796 unsigned long ref = 0;
1797
1798 /*
1799 * When adding a module, we need to check if tracers are
1800 * currently enabled and if they are set to trace all functions.
1801 * If they are, we need to enable the module functions as well
1802 * as update the reference counts for those function records.
1803 */
1804 if (mod) {
1805 struct ftrace_ops *ops;
1806
1807 for (ops = ftrace_ops_list;
1808 ops != &ftrace_list_end; ops = ops->next) {
1809 if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1810 ops_traces_mod(ops))
1811 ref++;
1812 }
1813 }
1814
1815 start = ftrace_now(raw_smp_processor_id());
1816 ftrace_update_cnt = 0;
1817
1818 while (ftrace_new_addrs) {
1819
1820 /* If something went wrong, bail without enabling anything */
1821 if (unlikely(ftrace_disabled))
1822 return -1;
1823
1824 p = ftrace_new_addrs;
1825 ftrace_new_addrs = p->newlist;
1826 p->flags = ref;
1827
1828 /*
1829 * Do the initial record conversion from mcount jump
1830 * to the NOP instructions.
1831 */
1832 if (!ftrace_code_disable(mod, p)) {
1833 ftrace_free_rec(p);
1834 /* Game over */
1835 break;
1836 }
1837
1838 ftrace_update_cnt++;
1839
1840 /*
1841 * If the tracing is enabled, go ahead and enable the record.
1842 *
1843 * The reason not to enable the record immediatelly is the
1844 * inherent check of ftrace_make_nop/ftrace_make_call for
1845 * correct previous instructions. Making first the NOP
1846 * conversion puts the module to the correct state, thus
1847 * passing the ftrace_make_call check.
1848 */
1849 if (ftrace_start_up && ref) {
1850 int failed = __ftrace_replace_code(p, 1);
1851 if (failed) {
1852 ftrace_bug(failed, p->ip);
1853 ftrace_free_rec(p);
1854 }
1855 }
1856 }
1857
1858 stop = ftrace_now(raw_smp_processor_id());
1859 ftrace_update_time = stop - start;
1860 ftrace_update_tot_cnt += ftrace_update_cnt;
1861
1862 return 0;
1863 }
1864
1865 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1866 {
1867 struct ftrace_page *pg;
1868 int cnt;
1869 int i;
1870
1871 /* allocate a few pages */
1872 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1873 if (!ftrace_pages_start)
1874 return -1;
1875
1876 /*
1877 * Allocate a few more pages.
1878 *
1879 * TODO: have some parser search vmlinux before
1880 * final linking to find all calls to ftrace.
1881 * Then we can:
1882 * a) know how many pages to allocate.
1883 * and/or
1884 * b) set up the table then.
1885 *
1886 * The dynamic code is still necessary for
1887 * modules.
1888 */
1889
1890 pg = ftrace_pages = ftrace_pages_start;
1891
1892 cnt = num_to_init / ENTRIES_PER_PAGE;
1893 pr_info("ftrace: allocating %ld entries in %d pages\n",
1894 num_to_init, cnt + 1);
1895
1896 for (i = 0; i < cnt; i++) {
1897 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1898
1899 /* If we fail, we'll try later anyway */
1900 if (!pg->next)
1901 break;
1902
1903 pg = pg->next;
1904 }
1905
1906 return 0;
1907 }
1908
1909 enum {
1910 FTRACE_ITER_FILTER = (1 << 0),
1911 FTRACE_ITER_NOTRACE = (1 << 1),
1912 FTRACE_ITER_PRINTALL = (1 << 2),
1913 FTRACE_ITER_HASH = (1 << 3),
1914 FTRACE_ITER_ENABLED = (1 << 4),
1915 };
1916
1917 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1918
1919 struct ftrace_iterator {
1920 loff_t pos;
1921 loff_t func_pos;
1922 struct ftrace_page *pg;
1923 struct dyn_ftrace *func;
1924 struct ftrace_func_probe *probe;
1925 struct trace_parser parser;
1926 struct ftrace_hash *hash;
1927 struct ftrace_ops *ops;
1928 int hidx;
1929 int idx;
1930 unsigned flags;
1931 };
1932
1933 static void *
1934 t_hash_next(struct seq_file *m, loff_t *pos)
1935 {
1936 struct ftrace_iterator *iter = m->private;
1937 struct hlist_node *hnd = NULL;
1938 struct hlist_head *hhd;
1939
1940 (*pos)++;
1941 iter->pos = *pos;
1942
1943 if (iter->probe)
1944 hnd = &iter->probe->node;
1945 retry:
1946 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1947 return NULL;
1948
1949 hhd = &ftrace_func_hash[iter->hidx];
1950
1951 if (hlist_empty(hhd)) {
1952 iter->hidx++;
1953 hnd = NULL;
1954 goto retry;
1955 }
1956
1957 if (!hnd)
1958 hnd = hhd->first;
1959 else {
1960 hnd = hnd->next;
1961 if (!hnd) {
1962 iter->hidx++;
1963 goto retry;
1964 }
1965 }
1966
1967 if (WARN_ON_ONCE(!hnd))
1968 return NULL;
1969
1970 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1971
1972 return iter;
1973 }
1974
1975 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1976 {
1977 struct ftrace_iterator *iter = m->private;
1978 void *p = NULL;
1979 loff_t l;
1980
1981 if (iter->func_pos > *pos)
1982 return NULL;
1983
1984 iter->hidx = 0;
1985 for (l = 0; l <= (*pos - iter->func_pos); ) {
1986 p = t_hash_next(m, &l);
1987 if (!p)
1988 break;
1989 }
1990 if (!p)
1991 return NULL;
1992
1993 /* Only set this if we have an item */
1994 iter->flags |= FTRACE_ITER_HASH;
1995
1996 return iter;
1997 }
1998
1999 static int
2000 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2001 {
2002 struct ftrace_func_probe *rec;
2003
2004 rec = iter->probe;
2005 if (WARN_ON_ONCE(!rec))
2006 return -EIO;
2007
2008 if (rec->ops->print)
2009 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2010
2011 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2012
2013 if (rec->data)
2014 seq_printf(m, ":%p", rec->data);
2015 seq_putc(m, '\n');
2016
2017 return 0;
2018 }
2019
2020 static void *
2021 t_next(struct seq_file *m, void *v, loff_t *pos)
2022 {
2023 struct ftrace_iterator *iter = m->private;
2024 struct ftrace_ops *ops = &global_ops;
2025 struct dyn_ftrace *rec = NULL;
2026
2027 if (unlikely(ftrace_disabled))
2028 return NULL;
2029
2030 if (iter->flags & FTRACE_ITER_HASH)
2031 return t_hash_next(m, pos);
2032
2033 (*pos)++;
2034 iter->pos = iter->func_pos = *pos;
2035
2036 if (iter->flags & FTRACE_ITER_PRINTALL)
2037 return t_hash_start(m, pos);
2038
2039 retry:
2040 if (iter->idx >= iter->pg->index) {
2041 if (iter->pg->next) {
2042 iter->pg = iter->pg->next;
2043 iter->idx = 0;
2044 goto retry;
2045 }
2046 } else {
2047 rec = &iter->pg->records[iter->idx++];
2048 if ((rec->flags & FTRACE_FL_FREE) ||
2049
2050 ((iter->flags & FTRACE_ITER_FILTER) &&
2051 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2052
2053 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2054 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2055
2056 ((iter->flags & FTRACE_ITER_ENABLED) &&
2057 !(rec->flags & ~FTRACE_FL_MASK))) {
2058
2059 rec = NULL;
2060 goto retry;
2061 }
2062 }
2063
2064 if (!rec)
2065 return t_hash_start(m, pos);
2066
2067 iter->func = rec;
2068
2069 return iter;
2070 }
2071
2072 static void reset_iter_read(struct ftrace_iterator *iter)
2073 {
2074 iter->pos = 0;
2075 iter->func_pos = 0;
2076 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2077 }
2078
2079 static void *t_start(struct seq_file *m, loff_t *pos)
2080 {
2081 struct ftrace_iterator *iter = m->private;
2082 struct ftrace_ops *ops = &global_ops;
2083 void *p = NULL;
2084 loff_t l;
2085
2086 mutex_lock(&ftrace_lock);
2087
2088 if (unlikely(ftrace_disabled))
2089 return NULL;
2090
2091 /*
2092 * If an lseek was done, then reset and start from beginning.
2093 */
2094 if (*pos < iter->pos)
2095 reset_iter_read(iter);
2096
2097 /*
2098 * For set_ftrace_filter reading, if we have the filter
2099 * off, we can short cut and just print out that all
2100 * functions are enabled.
2101 */
2102 if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
2103 if (*pos > 0)
2104 return t_hash_start(m, pos);
2105 iter->flags |= FTRACE_ITER_PRINTALL;
2106 /* reset in case of seek/pread */
2107 iter->flags &= ~FTRACE_ITER_HASH;
2108 return iter;
2109 }
2110
2111 if (iter->flags & FTRACE_ITER_HASH)
2112 return t_hash_start(m, pos);
2113
2114 /*
2115 * Unfortunately, we need to restart at ftrace_pages_start
2116 * every time we let go of the ftrace_mutex. This is because
2117 * those pointers can change without the lock.
2118 */
2119 iter->pg = ftrace_pages_start;
2120 iter->idx = 0;
2121 for (l = 0; l <= *pos; ) {
2122 p = t_next(m, p, &l);
2123 if (!p)
2124 break;
2125 }
2126
2127 if (!p) {
2128 if (iter->flags & FTRACE_ITER_FILTER)
2129 return t_hash_start(m, pos);
2130
2131 return NULL;
2132 }
2133
2134 return iter;
2135 }
2136
2137 static void t_stop(struct seq_file *m, void *p)
2138 {
2139 mutex_unlock(&ftrace_lock);
2140 }
2141
2142 static int t_show(struct seq_file *m, void *v)
2143 {
2144 struct ftrace_iterator *iter = m->private;
2145 struct dyn_ftrace *rec;
2146
2147 if (iter->flags & FTRACE_ITER_HASH)
2148 return t_hash_show(m, iter);
2149
2150 if (iter->flags & FTRACE_ITER_PRINTALL) {
2151 seq_printf(m, "#### all functions enabled ####\n");
2152 return 0;
2153 }
2154
2155 rec = iter->func;
2156
2157 if (!rec)
2158 return 0;
2159
2160 seq_printf(m, "%ps", (void *)rec->ip);
2161 if (iter->flags & FTRACE_ITER_ENABLED)
2162 seq_printf(m, " (%ld)",
2163 rec->flags & ~FTRACE_FL_MASK);
2164 seq_printf(m, "\n");
2165
2166 return 0;
2167 }
2168
2169 static const struct seq_operations show_ftrace_seq_ops = {
2170 .start = t_start,
2171 .next = t_next,
2172 .stop = t_stop,
2173 .show = t_show,
2174 };
2175
2176 static int
2177 ftrace_avail_open(struct inode *inode, struct file *file)
2178 {
2179 struct ftrace_iterator *iter;
2180 int ret;
2181
2182 if (unlikely(ftrace_disabled))
2183 return -ENODEV;
2184
2185 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2186 if (!iter)
2187 return -ENOMEM;
2188
2189 iter->pg = ftrace_pages_start;
2190
2191 ret = seq_open(file, &show_ftrace_seq_ops);
2192 if (!ret) {
2193 struct seq_file *m = file->private_data;
2194
2195 m->private = iter;
2196 } else {
2197 kfree(iter);
2198 }
2199
2200 return ret;
2201 }
2202
2203 static int
2204 ftrace_enabled_open(struct inode *inode, struct file *file)
2205 {
2206 struct ftrace_iterator *iter;
2207 int ret;
2208
2209 if (unlikely(ftrace_disabled))
2210 return -ENODEV;
2211
2212 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2213 if (!iter)
2214 return -ENOMEM;
2215
2216 iter->pg = ftrace_pages_start;
2217 iter->flags = FTRACE_ITER_ENABLED;
2218
2219 ret = seq_open(file, &show_ftrace_seq_ops);
2220 if (!ret) {
2221 struct seq_file *m = file->private_data;
2222
2223 m->private = iter;
2224 } else {
2225 kfree(iter);
2226 }
2227
2228 return ret;
2229 }
2230
2231 static void ftrace_filter_reset(struct ftrace_hash *hash)
2232 {
2233 mutex_lock(&ftrace_lock);
2234 ftrace_hash_clear(hash);
2235 mutex_unlock(&ftrace_lock);
2236 }
2237
2238 static int
2239 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2240 struct inode *inode, struct file *file)
2241 {
2242 struct ftrace_iterator *iter;
2243 struct ftrace_hash *hash;
2244 int ret = 0;
2245
2246 if (unlikely(ftrace_disabled))
2247 return -ENODEV;
2248
2249 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2250 if (!iter)
2251 return -ENOMEM;
2252
2253 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2254 kfree(iter);
2255 return -ENOMEM;
2256 }
2257
2258 if (flag & FTRACE_ITER_NOTRACE)
2259 hash = ops->notrace_hash;
2260 else
2261 hash = ops->filter_hash;
2262
2263 iter->ops = ops;
2264 iter->flags = flag;
2265
2266 if (file->f_mode & FMODE_WRITE) {
2267 mutex_lock(&ftrace_lock);
2268 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2269 mutex_unlock(&ftrace_lock);
2270
2271 if (!iter->hash) {
2272 trace_parser_put(&iter->parser);
2273 kfree(iter);
2274 return -ENOMEM;
2275 }
2276 }
2277
2278 mutex_lock(&ftrace_regex_lock);
2279
2280 if ((file->f_mode & FMODE_WRITE) &&
2281 (file->f_flags & O_TRUNC))
2282 ftrace_filter_reset(iter->hash);
2283
2284 if (file->f_mode & FMODE_READ) {
2285 iter->pg = ftrace_pages_start;
2286
2287 ret = seq_open(file, &show_ftrace_seq_ops);
2288 if (!ret) {
2289 struct seq_file *m = file->private_data;
2290 m->private = iter;
2291 } else {
2292 /* Failed */
2293 free_ftrace_hash(iter->hash);
2294 trace_parser_put(&iter->parser);
2295 kfree(iter);
2296 }
2297 } else
2298 file->private_data = iter;
2299 mutex_unlock(&ftrace_regex_lock);
2300
2301 return ret;
2302 }
2303
2304 static int
2305 ftrace_filter_open(struct inode *inode, struct file *file)
2306 {
2307 return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2308 inode, file);
2309 }
2310
2311 static int
2312 ftrace_notrace_open(struct inode *inode, struct file *file)
2313 {
2314 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2315 inode, file);
2316 }
2317
2318 static loff_t
2319 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2320 {
2321 loff_t ret;
2322
2323 if (file->f_mode & FMODE_READ)
2324 ret = seq_lseek(file, offset, origin);
2325 else
2326 file->f_pos = ret = 1;
2327
2328 return ret;
2329 }
2330
2331 static int ftrace_match(char *str, char *regex, int len, int type)
2332 {
2333 int matched = 0;
2334 int slen;
2335
2336 switch (type) {
2337 case MATCH_FULL:
2338 if (strcmp(str, regex) == 0)
2339 matched = 1;
2340 break;
2341 case MATCH_FRONT_ONLY:
2342 if (strncmp(str, regex, len) == 0)
2343 matched = 1;
2344 break;
2345 case MATCH_MIDDLE_ONLY:
2346 if (strstr(str, regex))
2347 matched = 1;
2348 break;
2349 case MATCH_END_ONLY:
2350 slen = strlen(str);
2351 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2352 matched = 1;
2353 break;
2354 }
2355
2356 return matched;
2357 }
2358
2359 static int
2360 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2361 {
2362 struct ftrace_func_entry *entry;
2363 int ret = 0;
2364
2365 entry = ftrace_lookup_ip(hash, rec->ip);
2366 if (not) {
2367 /* Do nothing if it doesn't exist */
2368 if (!entry)
2369 return 0;
2370
2371 free_hash_entry(hash, entry);
2372 } else {
2373 /* Do nothing if it exists */
2374 if (entry)
2375 return 0;
2376
2377 ret = add_hash_entry(hash, rec->ip);
2378 }
2379 return ret;
2380 }
2381
2382 static int
2383 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2384 char *regex, int len, int type)
2385 {
2386 char str[KSYM_SYMBOL_LEN];
2387 char *modname;
2388
2389 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2390
2391 if (mod) {
2392 /* module lookup requires matching the module */
2393 if (!modname || strcmp(modname, mod))
2394 return 0;
2395
2396 /* blank search means to match all funcs in the mod */
2397 if (!len)
2398 return 1;
2399 }
2400
2401 return ftrace_match(str, regex, len, type);
2402 }
2403
2404 static int
2405 match_records(struct ftrace_hash *hash, char *buff,
2406 int len, char *mod, int not)
2407 {
2408 unsigned search_len = 0;
2409 struct ftrace_page *pg;
2410 struct dyn_ftrace *rec;
2411 int type = MATCH_FULL;
2412 char *search = buff;
2413 int found = 0;
2414 int ret;
2415
2416 if (len) {
2417 type = filter_parse_regex(buff, len, &search, &not);
2418 search_len = strlen(search);
2419 }
2420
2421 mutex_lock(&ftrace_lock);
2422
2423 if (unlikely(ftrace_disabled))
2424 goto out_unlock;
2425
2426 do_for_each_ftrace_rec(pg, rec) {
2427
2428 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2429 ret = enter_record(hash, rec, not);
2430 if (ret < 0) {
2431 found = ret;
2432 goto out_unlock;
2433 }
2434 found = 1;
2435 }
2436 } while_for_each_ftrace_rec();
2437 out_unlock:
2438 mutex_unlock(&ftrace_lock);
2439
2440 return found;
2441 }
2442
2443 static int
2444 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2445 {
2446 return match_records(hash, buff, len, NULL, 0);
2447 }
2448
2449 static int
2450 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2451 {
2452 int not = 0;
2453
2454 /* blank or '*' mean the same */
2455 if (strcmp(buff, "*") == 0)
2456 buff[0] = 0;
2457
2458 /* handle the case of 'dont filter this module' */
2459 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2460 buff[0] = 0;
2461 not = 1;
2462 }
2463
2464 return match_records(hash, buff, strlen(buff), mod, not);
2465 }
2466
2467 /*
2468 * We register the module command as a template to show others how
2469 * to register the a command as well.
2470 */
2471
2472 static int
2473 ftrace_mod_callback(struct ftrace_hash *hash,
2474 char *func, char *cmd, char *param, int enable)
2475 {
2476 char *mod;
2477 int ret = -EINVAL;
2478
2479 /*
2480 * cmd == 'mod' because we only registered this func
2481 * for the 'mod' ftrace_func_command.
2482 * But if you register one func with multiple commands,
2483 * you can tell which command was used by the cmd
2484 * parameter.
2485 */
2486
2487 /* we must have a module name */
2488 if (!param)
2489 return ret;
2490
2491 mod = strsep(&param, ":");
2492 if (!strlen(mod))
2493 return ret;
2494
2495 ret = ftrace_match_module_records(hash, func, mod);
2496 if (!ret)
2497 ret = -EINVAL;
2498 if (ret < 0)
2499 return ret;
2500
2501 return 0;
2502 }
2503
2504 static struct ftrace_func_command ftrace_mod_cmd = {
2505 .name = "mod",
2506 .func = ftrace_mod_callback,
2507 };
2508
2509 static int __init ftrace_mod_cmd_init(void)
2510 {
2511 return register_ftrace_command(&ftrace_mod_cmd);
2512 }
2513 device_initcall(ftrace_mod_cmd_init);
2514
2515 static void
2516 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2517 {
2518 struct ftrace_func_probe *entry;
2519 struct hlist_head *hhd;
2520 struct hlist_node *n;
2521 unsigned long key;
2522
2523 key = hash_long(ip, FTRACE_HASH_BITS);
2524
2525 hhd = &ftrace_func_hash[key];
2526
2527 if (hlist_empty(hhd))
2528 return;
2529
2530 /*
2531 * Disable preemption for these calls to prevent a RCU grace
2532 * period. This syncs the hash iteration and freeing of items
2533 * on the hash. rcu_read_lock is too dangerous here.
2534 */
2535 preempt_disable_notrace();
2536 hlist_for_each_entry_rcu(entry, n, hhd, node) {
2537 if (entry->ip == ip)
2538 entry->ops->func(ip, parent_ip, &entry->data);
2539 }
2540 preempt_enable_notrace();
2541 }
2542
2543 static struct ftrace_ops trace_probe_ops __read_mostly =
2544 {
2545 .func = function_trace_probe_call,
2546 };
2547
2548 static int ftrace_probe_registered;
2549
2550 static void __enable_ftrace_function_probe(void)
2551 {
2552 int ret;
2553 int i;
2554
2555 if (ftrace_probe_registered)
2556 return;
2557
2558 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2559 struct hlist_head *hhd = &ftrace_func_hash[i];
2560 if (hhd->first)
2561 break;
2562 }
2563 /* Nothing registered? */
2564 if (i == FTRACE_FUNC_HASHSIZE)
2565 return;
2566
2567 ret = __register_ftrace_function(&trace_probe_ops);
2568 if (!ret)
2569 ret = ftrace_startup(&trace_probe_ops, 0);
2570
2571 ftrace_probe_registered = 1;
2572 }
2573
2574 static void __disable_ftrace_function_probe(void)
2575 {
2576 int ret;
2577 int i;
2578
2579 if (!ftrace_probe_registered)
2580 return;
2581
2582 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2583 struct hlist_head *hhd = &ftrace_func_hash[i];
2584 if (hhd->first)
2585 return;
2586 }
2587
2588 /* no more funcs left */
2589 ret = __unregister_ftrace_function(&trace_probe_ops);
2590 if (!ret)
2591 ftrace_shutdown(&trace_probe_ops, 0);
2592
2593 ftrace_probe_registered = 0;
2594 }
2595
2596
2597 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2598 {
2599 struct ftrace_func_probe *entry =
2600 container_of(rhp, struct ftrace_func_probe, rcu);
2601
2602 if (entry->ops->free)
2603 entry->ops->free(&entry->data);
2604 kfree(entry);
2605 }
2606
2607
2608 int
2609 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2610 void *data)
2611 {
2612 struct ftrace_func_probe *entry;
2613 struct ftrace_page *pg;
2614 struct dyn_ftrace *rec;
2615 int type, len, not;
2616 unsigned long key;
2617 int count = 0;
2618 char *search;
2619
2620 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2621 len = strlen(search);
2622
2623 /* we do not support '!' for function probes */
2624 if (WARN_ON(not))
2625 return -EINVAL;
2626
2627 mutex_lock(&ftrace_lock);
2628
2629 if (unlikely(ftrace_disabled))
2630 goto out_unlock;
2631
2632 do_for_each_ftrace_rec(pg, rec) {
2633
2634 if (!ftrace_match_record(rec, NULL, search, len, type))
2635 continue;
2636
2637 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2638 if (!entry) {
2639 /* If we did not process any, then return error */
2640 if (!count)
2641 count = -ENOMEM;
2642 goto out_unlock;
2643 }
2644
2645 count++;
2646
2647 entry->data = data;
2648
2649 /*
2650 * The caller might want to do something special
2651 * for each function we find. We call the callback
2652 * to give the caller an opportunity to do so.
2653 */
2654 if (ops->callback) {
2655 if (ops->callback(rec->ip, &entry->data) < 0) {
2656 /* caller does not like this func */
2657 kfree(entry);
2658 continue;
2659 }
2660 }
2661
2662 entry->ops = ops;
2663 entry->ip = rec->ip;
2664
2665 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2666 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2667
2668 } while_for_each_ftrace_rec();
2669 __enable_ftrace_function_probe();
2670
2671 out_unlock:
2672 mutex_unlock(&ftrace_lock);
2673
2674 return count;
2675 }
2676
2677 enum {
2678 PROBE_TEST_FUNC = 1,
2679 PROBE_TEST_DATA = 2
2680 };
2681
2682 static void
2683 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2684 void *data, int flags)
2685 {
2686 struct ftrace_func_probe *entry;
2687 struct hlist_node *n, *tmp;
2688 char str[KSYM_SYMBOL_LEN];
2689 int type = MATCH_FULL;
2690 int i, len = 0;
2691 char *search;
2692
2693 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2694 glob = NULL;
2695 else if (glob) {
2696 int not;
2697
2698 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2699 len = strlen(search);
2700
2701 /* we do not support '!' for function probes */
2702 if (WARN_ON(not))
2703 return;
2704 }
2705
2706 mutex_lock(&ftrace_lock);
2707 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2708 struct hlist_head *hhd = &ftrace_func_hash[i];
2709
2710 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2711
2712 /* break up if statements for readability */
2713 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2714 continue;
2715
2716 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2717 continue;
2718
2719 /* do this last, since it is the most expensive */
2720 if (glob) {
2721 kallsyms_lookup(entry->ip, NULL, NULL,
2722 NULL, str);
2723 if (!ftrace_match(str, glob, len, type))
2724 continue;
2725 }
2726
2727 hlist_del(&entry->node);
2728 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2729 }
2730 }
2731 __disable_ftrace_function_probe();
2732 mutex_unlock(&ftrace_lock);
2733 }
2734
2735 void
2736 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2737 void *data)
2738 {
2739 __unregister_ftrace_function_probe(glob, ops, data,
2740 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2741 }
2742
2743 void
2744 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2745 {
2746 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2747 }
2748
2749 void unregister_ftrace_function_probe_all(char *glob)
2750 {
2751 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2752 }
2753
2754 static LIST_HEAD(ftrace_commands);
2755 static DEFINE_MUTEX(ftrace_cmd_mutex);
2756
2757 int register_ftrace_command(struct ftrace_func_command *cmd)
2758 {
2759 struct ftrace_func_command *p;
2760 int ret = 0;
2761
2762 mutex_lock(&ftrace_cmd_mutex);
2763 list_for_each_entry(p, &ftrace_commands, list) {
2764 if (strcmp(cmd->name, p->name) == 0) {
2765 ret = -EBUSY;
2766 goto out_unlock;
2767 }
2768 }
2769 list_add(&cmd->list, &ftrace_commands);
2770 out_unlock:
2771 mutex_unlock(&ftrace_cmd_mutex);
2772
2773 return ret;
2774 }
2775
2776 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2777 {
2778 struct ftrace_func_command *p, *n;
2779 int ret = -ENODEV;
2780
2781 mutex_lock(&ftrace_cmd_mutex);
2782 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2783 if (strcmp(cmd->name, p->name) == 0) {
2784 ret = 0;
2785 list_del_init(&p->list);
2786 goto out_unlock;
2787 }
2788 }
2789 out_unlock:
2790 mutex_unlock(&ftrace_cmd_mutex);
2791
2792 return ret;
2793 }
2794
2795 static int ftrace_process_regex(struct ftrace_hash *hash,
2796 char *buff, int len, int enable)
2797 {
2798 char *func, *command, *next = buff;
2799 struct ftrace_func_command *p;
2800 int ret = -EINVAL;
2801
2802 func = strsep(&next, ":");
2803
2804 if (!next) {
2805 ret = ftrace_match_records(hash, func, len);
2806 if (!ret)
2807 ret = -EINVAL;
2808 if (ret < 0)
2809 return ret;
2810 return 0;
2811 }
2812
2813 /* command found */
2814
2815 command = strsep(&next, ":");
2816
2817 mutex_lock(&ftrace_cmd_mutex);
2818 list_for_each_entry(p, &ftrace_commands, list) {
2819 if (strcmp(p->name, command) == 0) {
2820 ret = p->func(hash, func, command, next, enable);
2821 goto out_unlock;
2822 }
2823 }
2824 out_unlock:
2825 mutex_unlock(&ftrace_cmd_mutex);
2826
2827 return ret;
2828 }
2829
2830 static ssize_t
2831 ftrace_regex_write(struct file *file, const char __user *ubuf,
2832 size_t cnt, loff_t *ppos, int enable)
2833 {
2834 struct ftrace_iterator *iter;
2835 struct trace_parser *parser;
2836 ssize_t ret, read;
2837
2838 if (!cnt)
2839 return 0;
2840
2841 mutex_lock(&ftrace_regex_lock);
2842
2843 ret = -ENODEV;
2844 if (unlikely(ftrace_disabled))
2845 goto out_unlock;
2846
2847 if (file->f_mode & FMODE_READ) {
2848 struct seq_file *m = file->private_data;
2849 iter = m->private;
2850 } else
2851 iter = file->private_data;
2852
2853 parser = &iter->parser;
2854 read = trace_get_user(parser, ubuf, cnt, ppos);
2855
2856 if (read >= 0 && trace_parser_loaded(parser) &&
2857 !trace_parser_cont(parser)) {
2858 ret = ftrace_process_regex(iter->hash, parser->buffer,
2859 parser->idx, enable);
2860 trace_parser_clear(parser);
2861 if (ret)
2862 goto out_unlock;
2863 }
2864
2865 ret = read;
2866 out_unlock:
2867 mutex_unlock(&ftrace_regex_lock);
2868
2869 return ret;
2870 }
2871
2872 static ssize_t
2873 ftrace_filter_write(struct file *file, const char __user *ubuf,
2874 size_t cnt, loff_t *ppos)
2875 {
2876 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2877 }
2878
2879 static ssize_t
2880 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2881 size_t cnt, loff_t *ppos)
2882 {
2883 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2884 }
2885
2886 static int
2887 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
2888 int reset, int enable)
2889 {
2890 struct ftrace_hash **orig_hash;
2891 struct ftrace_hash *hash;
2892 int ret;
2893
2894 /* All global ops uses the global ops filters */
2895 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
2896 ops = &global_ops;
2897
2898 if (unlikely(ftrace_disabled))
2899 return -ENODEV;
2900
2901 if (enable)
2902 orig_hash = &ops->filter_hash;
2903 else
2904 orig_hash = &ops->notrace_hash;
2905
2906 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
2907 if (!hash)
2908 return -ENOMEM;
2909
2910 mutex_lock(&ftrace_regex_lock);
2911 if (reset)
2912 ftrace_filter_reset(hash);
2913 if (buf)
2914 ftrace_match_records(hash, buf, len);
2915
2916 mutex_lock(&ftrace_lock);
2917 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
2918 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
2919 && ftrace_enabled)
2920 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2921
2922 mutex_unlock(&ftrace_lock);
2923
2924 mutex_unlock(&ftrace_regex_lock);
2925
2926 free_ftrace_hash(hash);
2927 return ret;
2928 }
2929
2930 /**
2931 * ftrace_set_filter - set a function to filter on in ftrace
2932 * @ops - the ops to set the filter with
2933 * @buf - the string that holds the function filter text.
2934 * @len - the length of the string.
2935 * @reset - non zero to reset all filters before applying this filter.
2936 *
2937 * Filters denote which functions should be enabled when tracing is enabled.
2938 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2939 */
2940 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
2941 int len, int reset)
2942 {
2943 ftrace_set_regex(ops, buf, len, reset, 1);
2944 }
2945 EXPORT_SYMBOL_GPL(ftrace_set_filter);
2946
2947 /**
2948 * ftrace_set_notrace - set a function to not trace in ftrace
2949 * @ops - the ops to set the notrace filter with
2950 * @buf - the string that holds the function notrace text.
2951 * @len - the length of the string.
2952 * @reset - non zero to reset all filters before applying this filter.
2953 *
2954 * Notrace Filters denote which functions should not be enabled when tracing
2955 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2956 * for tracing.
2957 */
2958 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
2959 int len, int reset)
2960 {
2961 ftrace_set_regex(ops, buf, len, reset, 0);
2962 }
2963 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
2964 /**
2965 * ftrace_set_filter - set a function to filter on in ftrace
2966 * @ops - the ops to set the filter with
2967 * @buf - the string that holds the function filter text.
2968 * @len - the length of the string.
2969 * @reset - non zero to reset all filters before applying this filter.
2970 *
2971 * Filters denote which functions should be enabled when tracing is enabled.
2972 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2973 */
2974 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
2975 {
2976 ftrace_set_regex(&global_ops, buf, len, reset, 1);
2977 }
2978 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
2979
2980 /**
2981 * ftrace_set_notrace - set a function to not trace in ftrace
2982 * @ops - the ops to set the notrace filter with
2983 * @buf - the string that holds the function notrace text.
2984 * @len - the length of the string.
2985 * @reset - non zero to reset all filters before applying this filter.
2986 *
2987 * Notrace Filters denote which functions should not be enabled when tracing
2988 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2989 * for tracing.
2990 */
2991 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
2992 {
2993 ftrace_set_regex(&global_ops, buf, len, reset, 0);
2994 }
2995 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
2996
2997 /*
2998 * command line interface to allow users to set filters on boot up.
2999 */
3000 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3001 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3002 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3003
3004 static int __init set_ftrace_notrace(char *str)
3005 {
3006 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3007 return 1;
3008 }
3009 __setup("ftrace_notrace=", set_ftrace_notrace);
3010
3011 static int __init set_ftrace_filter(char *str)
3012 {
3013 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3014 return 1;
3015 }
3016 __setup("ftrace_filter=", set_ftrace_filter);
3017
3018 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3019 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3020 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3021
3022 static int __init set_graph_function(char *str)
3023 {
3024 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3025 return 1;
3026 }
3027 __setup("ftrace_graph_filter=", set_graph_function);
3028
3029 static void __init set_ftrace_early_graph(char *buf)
3030 {
3031 int ret;
3032 char *func;
3033
3034 while (buf) {
3035 func = strsep(&buf, ",");
3036 /* we allow only one expression at a time */
3037 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3038 func);
3039 if (ret)
3040 printk(KERN_DEBUG "ftrace: function %s not "
3041 "traceable\n", func);
3042 }
3043 }
3044 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3045
3046 static void __init
3047 set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3048 {
3049 char *func;
3050
3051 while (buf) {
3052 func = strsep(&buf, ",");
3053 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3054 }
3055 }
3056
3057 static void __init set_ftrace_early_filters(void)
3058 {
3059 if (ftrace_filter_buf[0])
3060 set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3061 if (ftrace_notrace_buf[0])
3062 set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3063 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3064 if (ftrace_graph_buf[0])
3065 set_ftrace_early_graph(ftrace_graph_buf);
3066 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3067 }
3068
3069 static int
3070 ftrace_regex_release(struct inode *inode, struct file *file)
3071 {
3072 struct seq_file *m = (struct seq_file *)file->private_data;
3073 struct ftrace_iterator *iter;
3074 struct ftrace_hash **orig_hash;
3075 struct trace_parser *parser;
3076 int filter_hash;
3077 int ret;
3078
3079 mutex_lock(&ftrace_regex_lock);
3080 if (file->f_mode & FMODE_READ) {
3081 iter = m->private;
3082
3083 seq_release(inode, file);
3084 } else
3085 iter = file->private_data;
3086
3087 parser = &iter->parser;
3088 if (trace_parser_loaded(parser)) {
3089 parser->buffer[parser->idx] = 0;
3090 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3091 }
3092
3093 trace_parser_put(parser);
3094
3095 if (file->f_mode & FMODE_WRITE) {
3096 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3097
3098 if (filter_hash)
3099 orig_hash = &iter->ops->filter_hash;
3100 else
3101 orig_hash = &iter->ops->notrace_hash;
3102
3103 mutex_lock(&ftrace_lock);
3104 ret = ftrace_hash_move(iter->ops, filter_hash,
3105 orig_hash, iter->hash);
3106 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3107 && ftrace_enabled)
3108 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
3109
3110 mutex_unlock(&ftrace_lock);
3111 }
3112 free_ftrace_hash(iter->hash);
3113 kfree(iter);
3114
3115 mutex_unlock(&ftrace_regex_lock);
3116 return 0;
3117 }
3118
3119 static const struct file_operations ftrace_avail_fops = {
3120 .open = ftrace_avail_open,
3121 .read = seq_read,
3122 .llseek = seq_lseek,
3123 .release = seq_release_private,
3124 };
3125
3126 static const struct file_operations ftrace_enabled_fops = {
3127 .open = ftrace_enabled_open,
3128 .read = seq_read,
3129 .llseek = seq_lseek,
3130 .release = seq_release_private,
3131 };
3132
3133 static const struct file_operations ftrace_filter_fops = {
3134 .open = ftrace_filter_open,
3135 .read = seq_read,
3136 .write = ftrace_filter_write,
3137 .llseek = ftrace_regex_lseek,
3138 .release = ftrace_regex_release,
3139 };
3140
3141 static const struct file_operations ftrace_notrace_fops = {
3142 .open = ftrace_notrace_open,
3143 .read = seq_read,
3144 .write = ftrace_notrace_write,
3145 .llseek = ftrace_regex_lseek,
3146 .release = ftrace_regex_release,
3147 };
3148
3149 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3150
3151 static DEFINE_MUTEX(graph_lock);
3152
3153 int ftrace_graph_count;
3154 int ftrace_graph_filter_enabled;
3155 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3156
3157 static void *
3158 __g_next(struct seq_file *m, loff_t *pos)
3159 {
3160 if (*pos >= ftrace_graph_count)
3161 return NULL;
3162 return &ftrace_graph_funcs[*pos];
3163 }
3164
3165 static void *
3166 g_next(struct seq_file *m, void *v, loff_t *pos)
3167 {
3168 (*pos)++;
3169 return __g_next(m, pos);
3170 }
3171
3172 static void *g_start(struct seq_file *m, loff_t *pos)
3173 {
3174 mutex_lock(&graph_lock);
3175
3176 /* Nothing, tell g_show to print all functions are enabled */
3177 if (!ftrace_graph_filter_enabled && !*pos)
3178 return (void *)1;
3179
3180 return __g_next(m, pos);
3181 }
3182
3183 static void g_stop(struct seq_file *m, void *p)
3184 {
3185 mutex_unlock(&graph_lock);
3186 }
3187
3188 static int g_show(struct seq_file *m, void *v)
3189 {
3190 unsigned long *ptr = v;
3191
3192 if (!ptr)
3193 return 0;
3194
3195 if (ptr == (unsigned long *)1) {
3196 seq_printf(m, "#### all functions enabled ####\n");
3197 return 0;
3198 }
3199
3200 seq_printf(m, "%ps\n", (void *)*ptr);
3201
3202 return 0;
3203 }
3204
3205 static const struct seq_operations ftrace_graph_seq_ops = {
3206 .start = g_start,
3207 .next = g_next,
3208 .stop = g_stop,
3209 .show = g_show,
3210 };
3211
3212 static int
3213 ftrace_graph_open(struct inode *inode, struct file *file)
3214 {
3215 int ret = 0;
3216
3217 if (unlikely(ftrace_disabled))
3218 return -ENODEV;
3219
3220 mutex_lock(&graph_lock);
3221 if ((file->f_mode & FMODE_WRITE) &&
3222 (file->f_flags & O_TRUNC)) {
3223 ftrace_graph_filter_enabled = 0;
3224 ftrace_graph_count = 0;
3225 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3226 }
3227 mutex_unlock(&graph_lock);
3228
3229 if (file->f_mode & FMODE_READ)
3230 ret = seq_open(file, &ftrace_graph_seq_ops);
3231
3232 return ret;
3233 }
3234
3235 static int
3236 ftrace_graph_release(struct inode *inode, struct file *file)
3237 {
3238 if (file->f_mode & FMODE_READ)
3239 seq_release(inode, file);
3240 return 0;
3241 }
3242
3243 static int
3244 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3245 {
3246 struct dyn_ftrace *rec;
3247 struct ftrace_page *pg;
3248 int search_len;
3249 int fail = 1;
3250 int type, not;
3251 char *search;
3252 bool exists;
3253 int i;
3254
3255 /* decode regex */
3256 type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3257 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3258 return -EBUSY;
3259
3260 search_len = strlen(search);
3261
3262 mutex_lock(&ftrace_lock);
3263
3264 if (unlikely(ftrace_disabled)) {
3265 mutex_unlock(&ftrace_lock);
3266 return -ENODEV;
3267 }
3268
3269 do_for_each_ftrace_rec(pg, rec) {
3270
3271 if (rec->flags & FTRACE_FL_FREE)
3272 continue;
3273
3274 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3275 /* if it is in the array */
3276 exists = false;
3277 for (i = 0; i < *idx; i++) {
3278 if (array[i] == rec->ip) {
3279 exists = true;
3280 break;
3281 }
3282 }
3283
3284 if (!not) {
3285 fail = 0;
3286 if (!exists) {
3287 array[(*idx)++] = rec->ip;
3288 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3289 goto out;
3290 }
3291 } else {
3292 if (exists) {
3293 array[i] = array[--(*idx)];
3294 array[*idx] = 0;
3295 fail = 0;
3296 }
3297 }
3298 }
3299 } while_for_each_ftrace_rec();
3300 out:
3301 mutex_unlock(&ftrace_lock);
3302
3303 if (fail)
3304 return -EINVAL;
3305
3306 ftrace_graph_filter_enabled = 1;
3307 return 0;
3308 }
3309
3310 static ssize_t
3311 ftrace_graph_write(struct file *file, const char __user *ubuf,
3312 size_t cnt, loff_t *ppos)
3313 {
3314 struct trace_parser parser;
3315 ssize_t read, ret;
3316
3317 if (!cnt)
3318 return 0;
3319
3320 mutex_lock(&graph_lock);
3321
3322 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3323 ret = -ENOMEM;
3324 goto out_unlock;
3325 }
3326
3327 read = trace_get_user(&parser, ubuf, cnt, ppos);
3328
3329 if (read >= 0 && trace_parser_loaded((&parser))) {
3330 parser.buffer[parser.idx] = 0;
3331
3332 /* we allow only one expression at a time */
3333 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3334 parser.buffer);
3335 if (ret)
3336 goto out_free;
3337 }
3338
3339 ret = read;
3340
3341 out_free:
3342 trace_parser_put(&parser);
3343 out_unlock:
3344 mutex_unlock(&graph_lock);
3345
3346 return ret;
3347 }
3348
3349 static const struct file_operations ftrace_graph_fops = {
3350 .open = ftrace_graph_open,
3351 .read = seq_read,
3352 .write = ftrace_graph_write,
3353 .release = ftrace_graph_release,
3354 .llseek = seq_lseek,
3355 };
3356 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3357
3358 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3359 {
3360
3361 trace_create_file("available_filter_functions", 0444,
3362 d_tracer, NULL, &ftrace_avail_fops);
3363
3364 trace_create_file("enabled_functions", 0444,
3365 d_tracer, NULL, &ftrace_enabled_fops);
3366
3367 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3368 NULL, &ftrace_filter_fops);
3369
3370 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3371 NULL, &ftrace_notrace_fops);
3372
3373 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3374 trace_create_file("set_graph_function", 0444, d_tracer,
3375 NULL,
3376 &ftrace_graph_fops);
3377 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3378
3379 return 0;
3380 }
3381
3382 static int ftrace_process_locs(struct module *mod,
3383 unsigned long *start,
3384 unsigned long *end)
3385 {
3386 unsigned long *p;
3387 unsigned long addr;
3388 unsigned long flags = 0; /* Shut up gcc */
3389
3390 mutex_lock(&ftrace_lock);
3391 p = start;
3392 while (p < end) {
3393 addr = ftrace_call_adjust(*p++);
3394 /*
3395 * Some architecture linkers will pad between
3396 * the different mcount_loc sections of different
3397 * object files to satisfy alignments.
3398 * Skip any NULL pointers.
3399 */
3400 if (!addr)
3401 continue;
3402 ftrace_record_ip(addr);
3403 }
3404
3405 /*
3406 * We only need to disable interrupts on start up
3407 * because we are modifying code that an interrupt
3408 * may execute, and the modification is not atomic.
3409 * But for modules, nothing runs the code we modify
3410 * until we are finished with it, and there's no
3411 * reason to cause large interrupt latencies while we do it.
3412 */
3413 if (!mod)
3414 local_irq_save(flags);
3415 ftrace_update_code(mod);
3416 if (!mod)
3417 local_irq_restore(flags);
3418 mutex_unlock(&ftrace_lock);
3419
3420 return 0;
3421 }
3422
3423 #ifdef CONFIG_MODULES
3424 void ftrace_release_mod(struct module *mod)
3425 {
3426 struct dyn_ftrace *rec;
3427 struct ftrace_page *pg;
3428
3429 mutex_lock(&ftrace_lock);
3430
3431 if (ftrace_disabled)
3432 goto out_unlock;
3433
3434 do_for_each_ftrace_rec(pg, rec) {
3435 if (within_module_core(rec->ip, mod)) {
3436 /*
3437 * rec->ip is changed in ftrace_free_rec()
3438 * It should not between s and e if record was freed.
3439 */
3440 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
3441 ftrace_free_rec(rec);
3442 }
3443 } while_for_each_ftrace_rec();
3444 out_unlock:
3445 mutex_unlock(&ftrace_lock);
3446 }
3447
3448 static void ftrace_init_module(struct module *mod,
3449 unsigned long *start, unsigned long *end)
3450 {
3451 if (ftrace_disabled || start == end)
3452 return;
3453 ftrace_process_locs(mod, start, end);
3454 }
3455
3456 static int ftrace_module_notify(struct notifier_block *self,
3457 unsigned long val, void *data)
3458 {
3459 struct module *mod = data;
3460
3461 switch (val) {
3462 case MODULE_STATE_COMING:
3463 ftrace_init_module(mod, mod->ftrace_callsites,
3464 mod->ftrace_callsites +
3465 mod->num_ftrace_callsites);
3466 break;
3467 case MODULE_STATE_GOING:
3468 ftrace_release_mod(mod);
3469 break;
3470 }
3471
3472 return 0;
3473 }
3474 #else
3475 static int ftrace_module_notify(struct notifier_block *self,
3476 unsigned long val, void *data)
3477 {
3478 return 0;
3479 }
3480 #endif /* CONFIG_MODULES */
3481
3482 struct notifier_block ftrace_module_nb = {
3483 .notifier_call = ftrace_module_notify,
3484 .priority = 0,
3485 };
3486
3487 extern unsigned long __start_mcount_loc[];
3488 extern unsigned long __stop_mcount_loc[];
3489
3490 void __init ftrace_init(void)
3491 {
3492 unsigned long count, addr, flags;
3493 int ret;
3494
3495 /* Keep the ftrace pointer to the stub */
3496 addr = (unsigned long)ftrace_stub;
3497
3498 local_irq_save(flags);
3499 ftrace_dyn_arch_init(&addr);
3500 local_irq_restore(flags);
3501
3502 /* ftrace_dyn_arch_init places the return code in addr */
3503 if (addr)
3504 goto failed;
3505
3506 count = __stop_mcount_loc - __start_mcount_loc;
3507
3508 ret = ftrace_dyn_table_alloc(count);
3509 if (ret)
3510 goto failed;
3511
3512 last_ftrace_enabled = ftrace_enabled = 1;
3513
3514 ret = ftrace_process_locs(NULL,
3515 __start_mcount_loc,
3516 __stop_mcount_loc);
3517
3518 ret = register_module_notifier(&ftrace_module_nb);
3519 if (ret)
3520 pr_warning("Failed to register trace ftrace module notifier\n");
3521
3522 set_ftrace_early_filters();
3523
3524 return;
3525 failed:
3526 ftrace_disabled = 1;
3527 }
3528
3529 #else
3530
3531 static struct ftrace_ops global_ops = {
3532 .func = ftrace_stub,
3533 };
3534
3535 static int __init ftrace_nodyn_init(void)
3536 {
3537 ftrace_enabled = 1;
3538 return 0;
3539 }
3540 device_initcall(ftrace_nodyn_init);
3541
3542 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3543 static inline void ftrace_startup_enable(int command) { }
3544 /* Keep as macros so we do not need to define the commands */
3545 # define ftrace_startup(ops, command) \
3546 ({ \
3547 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3548 0; \
3549 })
3550 # define ftrace_shutdown(ops, command) do { } while (0)
3551 # define ftrace_startup_sysctl() do { } while (0)
3552 # define ftrace_shutdown_sysctl() do { } while (0)
3553
3554 static inline int
3555 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3556 {
3557 return 1;
3558 }
3559
3560 #endif /* CONFIG_DYNAMIC_FTRACE */
3561
3562 static void
3563 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3564 {
3565 struct ftrace_ops *op;
3566
3567 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3568 return;
3569
3570 trace_recursion_set(TRACE_INTERNAL_BIT);
3571 /*
3572 * Some of the ops may be dynamically allocated,
3573 * they must be freed after a synchronize_sched().
3574 */
3575 preempt_disable_notrace();
3576 op = rcu_dereference_raw(ftrace_ops_list);
3577 while (op != &ftrace_list_end) {
3578 if (ftrace_ops_test(op, ip))
3579 op->func(ip, parent_ip);
3580 op = rcu_dereference_raw(op->next);
3581 };
3582 preempt_enable_notrace();
3583 trace_recursion_clear(TRACE_INTERNAL_BIT);
3584 }
3585
3586 static void clear_ftrace_swapper(void)
3587 {
3588 struct task_struct *p;
3589 int cpu;
3590
3591 get_online_cpus();
3592 for_each_online_cpu(cpu) {
3593 p = idle_task(cpu);
3594 clear_tsk_trace_trace(p);
3595 }
3596 put_online_cpus();
3597 }
3598
3599 static void set_ftrace_swapper(void)
3600 {
3601 struct task_struct *p;
3602 int cpu;
3603
3604 get_online_cpus();
3605 for_each_online_cpu(cpu) {
3606 p = idle_task(cpu);
3607 set_tsk_trace_trace(p);
3608 }
3609 put_online_cpus();
3610 }
3611
3612 static void clear_ftrace_pid(struct pid *pid)
3613 {
3614 struct task_struct *p;
3615
3616 rcu_read_lock();
3617 do_each_pid_task(pid, PIDTYPE_PID, p) {
3618 clear_tsk_trace_trace(p);
3619 } while_each_pid_task(pid, PIDTYPE_PID, p);
3620 rcu_read_unlock();
3621
3622 put_pid(pid);
3623 }
3624
3625 static void set_ftrace_pid(struct pid *pid)
3626 {
3627 struct task_struct *p;
3628
3629 rcu_read_lock();
3630 do_each_pid_task(pid, PIDTYPE_PID, p) {
3631 set_tsk_trace_trace(p);
3632 } while_each_pid_task(pid, PIDTYPE_PID, p);
3633 rcu_read_unlock();
3634 }
3635
3636 static void clear_ftrace_pid_task(struct pid *pid)
3637 {
3638 if (pid == ftrace_swapper_pid)
3639 clear_ftrace_swapper();
3640 else
3641 clear_ftrace_pid(pid);
3642 }
3643
3644 static void set_ftrace_pid_task(struct pid *pid)
3645 {
3646 if (pid == ftrace_swapper_pid)
3647 set_ftrace_swapper();
3648 else
3649 set_ftrace_pid(pid);
3650 }
3651
3652 static int ftrace_pid_add(int p)
3653 {
3654 struct pid *pid;
3655 struct ftrace_pid *fpid;
3656 int ret = -EINVAL;
3657
3658 mutex_lock(&ftrace_lock);
3659
3660 if (!p)
3661 pid = ftrace_swapper_pid;
3662 else
3663 pid = find_get_pid(p);
3664
3665 if (!pid)
3666 goto out;
3667
3668 ret = 0;
3669
3670 list_for_each_entry(fpid, &ftrace_pids, list)
3671 if (fpid->pid == pid)
3672 goto out_put;
3673
3674 ret = -ENOMEM;
3675
3676 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3677 if (!fpid)
3678 goto out_put;
3679
3680 list_add(&fpid->list, &ftrace_pids);
3681 fpid->pid = pid;
3682
3683 set_ftrace_pid_task(pid);
3684
3685 ftrace_update_pid_func();
3686 ftrace_startup_enable(0);
3687
3688 mutex_unlock(&ftrace_lock);
3689 return 0;
3690
3691 out_put:
3692 if (pid != ftrace_swapper_pid)
3693 put_pid(pid);
3694
3695 out:
3696 mutex_unlock(&ftrace_lock);
3697 return ret;
3698 }
3699
3700 static void ftrace_pid_reset(void)
3701 {
3702 struct ftrace_pid *fpid, *safe;
3703
3704 mutex_lock(&ftrace_lock);
3705 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3706 struct pid *pid = fpid->pid;
3707
3708 clear_ftrace_pid_task(pid);
3709
3710 list_del(&fpid->list);
3711 kfree(fpid);
3712 }
3713
3714 ftrace_update_pid_func();
3715 ftrace_startup_enable(0);
3716
3717 mutex_unlock(&ftrace_lock);
3718 }
3719
3720 static void *fpid_start(struct seq_file *m, loff_t *pos)
3721 {
3722 mutex_lock(&ftrace_lock);
3723
3724 if (list_empty(&ftrace_pids) && (!*pos))
3725 return (void *) 1;
3726
3727 return seq_list_start(&ftrace_pids, *pos);
3728 }
3729
3730 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3731 {
3732 if (v == (void *)1)
3733 return NULL;
3734
3735 return seq_list_next(v, &ftrace_pids, pos);
3736 }
3737
3738 static void fpid_stop(struct seq_file *m, void *p)
3739 {
3740 mutex_unlock(&ftrace_lock);
3741 }
3742
3743 static int fpid_show(struct seq_file *m, void *v)
3744 {
3745 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3746
3747 if (v == (void *)1) {
3748 seq_printf(m, "no pid\n");
3749 return 0;
3750 }
3751
3752 if (fpid->pid == ftrace_swapper_pid)
3753 seq_printf(m, "swapper tasks\n");
3754 else
3755 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3756
3757 return 0;
3758 }
3759
3760 static const struct seq_operations ftrace_pid_sops = {
3761 .start = fpid_start,
3762 .next = fpid_next,
3763 .stop = fpid_stop,
3764 .show = fpid_show,
3765 };
3766
3767 static int
3768 ftrace_pid_open(struct inode *inode, struct file *file)
3769 {
3770 int ret = 0;
3771
3772 if ((file->f_mode & FMODE_WRITE) &&
3773 (file->f_flags & O_TRUNC))
3774 ftrace_pid_reset();
3775
3776 if (file->f_mode & FMODE_READ)
3777 ret = seq_open(file, &ftrace_pid_sops);
3778
3779 return ret;
3780 }
3781
3782 static ssize_t
3783 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3784 size_t cnt, loff_t *ppos)
3785 {
3786 char buf[64], *tmp;
3787 long val;
3788 int ret;
3789
3790 if (cnt >= sizeof(buf))
3791 return -EINVAL;
3792
3793 if (copy_from_user(&buf, ubuf, cnt))
3794 return -EFAULT;
3795
3796 buf[cnt] = 0;
3797
3798 /*
3799 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3800 * to clean the filter quietly.
3801 */
3802 tmp = strstrip(buf);
3803 if (strlen(tmp) == 0)
3804 return 1;
3805
3806 ret = strict_strtol(tmp, 10, &val);
3807 if (ret < 0)
3808 return ret;
3809
3810 ret = ftrace_pid_add(val);
3811
3812 return ret ? ret : cnt;
3813 }
3814
3815 static int
3816 ftrace_pid_release(struct inode *inode, struct file *file)
3817 {
3818 if (file->f_mode & FMODE_READ)
3819 seq_release(inode, file);
3820
3821 return 0;
3822 }
3823
3824 static const struct file_operations ftrace_pid_fops = {
3825 .open = ftrace_pid_open,
3826 .write = ftrace_pid_write,
3827 .read = seq_read,
3828 .llseek = seq_lseek,
3829 .release = ftrace_pid_release,
3830 };
3831
3832 static __init int ftrace_init_debugfs(void)
3833 {
3834 struct dentry *d_tracer;
3835
3836 d_tracer = tracing_init_dentry();
3837 if (!d_tracer)
3838 return 0;
3839
3840 ftrace_init_dyn_debugfs(d_tracer);
3841
3842 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3843 NULL, &ftrace_pid_fops);
3844
3845 ftrace_profile_debugfs(d_tracer);
3846
3847 return 0;
3848 }
3849 fs_initcall(ftrace_init_debugfs);
3850
3851 /**
3852 * ftrace_kill - kill ftrace
3853 *
3854 * This function should be used by panic code. It stops ftrace
3855 * but in a not so nice way. If you need to simply kill ftrace
3856 * from a non-atomic section, use ftrace_kill.
3857 */
3858 void ftrace_kill(void)
3859 {
3860 ftrace_disabled = 1;
3861 ftrace_enabled = 0;
3862 clear_ftrace_function();
3863 }
3864
3865 /**
3866 * register_ftrace_function - register a function for profiling
3867 * @ops - ops structure that holds the function for profiling.
3868 *
3869 * Register a function to be called by all functions in the
3870 * kernel.
3871 *
3872 * Note: @ops->func and all the functions it calls must be labeled
3873 * with "notrace", otherwise it will go into a
3874 * recursive loop.
3875 */
3876 int register_ftrace_function(struct ftrace_ops *ops)
3877 {
3878 int ret = -1;
3879
3880 mutex_lock(&ftrace_lock);
3881
3882 if (unlikely(ftrace_disabled))
3883 goto out_unlock;
3884
3885 ret = __register_ftrace_function(ops);
3886 if (!ret)
3887 ret = ftrace_startup(ops, 0);
3888
3889
3890 out_unlock:
3891 mutex_unlock(&ftrace_lock);
3892 return ret;
3893 }
3894 EXPORT_SYMBOL_GPL(register_ftrace_function);
3895
3896 /**
3897 * unregister_ftrace_function - unregister a function for profiling.
3898 * @ops - ops structure that holds the function to unregister
3899 *
3900 * Unregister a function that was added to be called by ftrace profiling.
3901 */
3902 int unregister_ftrace_function(struct ftrace_ops *ops)
3903 {
3904 int ret;
3905
3906 mutex_lock(&ftrace_lock);
3907 ret = __unregister_ftrace_function(ops);
3908 if (!ret)
3909 ftrace_shutdown(ops, 0);
3910 mutex_unlock(&ftrace_lock);
3911
3912 return ret;
3913 }
3914 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
3915
3916 int
3917 ftrace_enable_sysctl(struct ctl_table *table, int write,
3918 void __user *buffer, size_t *lenp,
3919 loff_t *ppos)
3920 {
3921 int ret = -ENODEV;
3922
3923 mutex_lock(&ftrace_lock);
3924
3925 if (unlikely(ftrace_disabled))
3926 goto out;
3927
3928 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3929
3930 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3931 goto out;
3932
3933 last_ftrace_enabled = !!ftrace_enabled;
3934
3935 if (ftrace_enabled) {
3936
3937 ftrace_startup_sysctl();
3938
3939 /* we are starting ftrace again */
3940 if (ftrace_ops_list != &ftrace_list_end) {
3941 if (ftrace_ops_list->next == &ftrace_list_end)
3942 ftrace_trace_function = ftrace_ops_list->func;
3943 else
3944 ftrace_trace_function = ftrace_ops_list_func;
3945 }
3946
3947 } else {
3948 /* stopping ftrace calls (just send to ftrace_stub) */
3949 ftrace_trace_function = ftrace_stub;
3950
3951 ftrace_shutdown_sysctl();
3952 }
3953
3954 out:
3955 mutex_unlock(&ftrace_lock);
3956 return ret;
3957 }
3958
3959 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3960
3961 static int ftrace_graph_active;
3962 static struct notifier_block ftrace_suspend_notifier;
3963
3964 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3965 {
3966 return 0;
3967 }
3968
3969 /* The callbacks that hook a function */
3970 trace_func_graph_ret_t ftrace_graph_return =
3971 (trace_func_graph_ret_t)ftrace_stub;
3972 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3973
3974 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3975 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3976 {
3977 int i;
3978 int ret = 0;
3979 unsigned long flags;
3980 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3981 struct task_struct *g, *t;
3982
3983 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3984 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3985 * sizeof(struct ftrace_ret_stack),
3986 GFP_KERNEL);
3987 if (!ret_stack_list[i]) {
3988 start = 0;
3989 end = i;
3990 ret = -ENOMEM;
3991 goto free;
3992 }
3993 }
3994
3995 read_lock_irqsave(&tasklist_lock, flags);
3996 do_each_thread(g, t) {
3997 if (start == end) {
3998 ret = -EAGAIN;
3999 goto unlock;
4000 }
4001
4002 if (t->ret_stack == NULL) {
4003 atomic_set(&t->tracing_graph_pause, 0);
4004 atomic_set(&t->trace_overrun, 0);
4005 t->curr_ret_stack = -1;
4006 /* Make sure the tasks see the -1 first: */
4007 smp_wmb();
4008 t->ret_stack = ret_stack_list[start++];
4009 }
4010 } while_each_thread(g, t);
4011
4012 unlock:
4013 read_unlock_irqrestore(&tasklist_lock, flags);
4014 free:
4015 for (i = start; i < end; i++)
4016 kfree(ret_stack_list[i]);
4017 return ret;
4018 }
4019
4020 static void
4021 ftrace_graph_probe_sched_switch(void *ignore,
4022 struct task_struct *prev, struct task_struct *next)
4023 {
4024 unsigned long long timestamp;
4025 int index;
4026
4027 /*
4028 * Does the user want to count the time a function was asleep.
4029 * If so, do not update the time stamps.
4030 */
4031 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4032 return;
4033
4034 timestamp = trace_clock_local();
4035
4036 prev->ftrace_timestamp = timestamp;
4037
4038 /* only process tasks that we timestamped */
4039 if (!next->ftrace_timestamp)
4040 return;
4041
4042 /*
4043 * Update all the counters in next to make up for the
4044 * time next was sleeping.
4045 */
4046 timestamp -= next->ftrace_timestamp;
4047
4048 for (index = next->curr_ret_stack; index >= 0; index--)
4049 next->ret_stack[index].calltime += timestamp;
4050 }
4051
4052 /* Allocate a return stack for each task */
4053 static int start_graph_tracing(void)
4054 {
4055 struct ftrace_ret_stack **ret_stack_list;
4056 int ret, cpu;
4057
4058 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4059 sizeof(struct ftrace_ret_stack *),
4060 GFP_KERNEL);
4061
4062 if (!ret_stack_list)
4063 return -ENOMEM;
4064
4065 /* The cpu_boot init_task->ret_stack will never be freed */
4066 for_each_online_cpu(cpu) {
4067 if (!idle_task(cpu)->ret_stack)
4068 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4069 }
4070
4071 do {
4072 ret = alloc_retstack_tasklist(ret_stack_list);
4073 } while (ret == -EAGAIN);
4074
4075 if (!ret) {
4076 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4077 if (ret)
4078 pr_info("ftrace_graph: Couldn't activate tracepoint"
4079 " probe to kernel_sched_switch\n");
4080 }
4081
4082 kfree(ret_stack_list);
4083 return ret;
4084 }
4085
4086 /*
4087 * Hibernation protection.
4088 * The state of the current task is too much unstable during
4089 * suspend/restore to disk. We want to protect against that.
4090 */
4091 static int
4092 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4093 void *unused)
4094 {
4095 switch (state) {
4096 case PM_HIBERNATION_PREPARE:
4097 pause_graph_tracing();
4098 break;
4099
4100 case PM_POST_HIBERNATION:
4101 unpause_graph_tracing();
4102 break;
4103 }
4104 return NOTIFY_DONE;
4105 }
4106
4107 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4108 trace_func_graph_ent_t entryfunc)
4109 {
4110 int ret = 0;
4111
4112 mutex_lock(&ftrace_lock);
4113
4114 /* we currently allow only one tracer registered at a time */
4115 if (ftrace_graph_active) {
4116 ret = -EBUSY;
4117 goto out;
4118 }
4119
4120 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4121 register_pm_notifier(&ftrace_suspend_notifier);
4122
4123 ftrace_graph_active++;
4124 ret = start_graph_tracing();
4125 if (ret) {
4126 ftrace_graph_active--;
4127 goto out;
4128 }
4129
4130 ftrace_graph_return = retfunc;
4131 ftrace_graph_entry = entryfunc;
4132
4133 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4134
4135 out:
4136 mutex_unlock(&ftrace_lock);
4137 return ret;
4138 }
4139
4140 void unregister_ftrace_graph(void)
4141 {
4142 mutex_lock(&ftrace_lock);
4143
4144 if (unlikely(!ftrace_graph_active))
4145 goto out;
4146
4147 ftrace_graph_active--;
4148 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4149 ftrace_graph_entry = ftrace_graph_entry_stub;
4150 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4151 unregister_pm_notifier(&ftrace_suspend_notifier);
4152 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4153
4154 out:
4155 mutex_unlock(&ftrace_lock);
4156 }
4157
4158 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4159
4160 static void
4161 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4162 {
4163 atomic_set(&t->tracing_graph_pause, 0);
4164 atomic_set(&t->trace_overrun, 0);
4165 t->ftrace_timestamp = 0;
4166 /* make curr_ret_stack visible before we add the ret_stack */
4167 smp_wmb();
4168 t->ret_stack = ret_stack;
4169 }
4170
4171 /*
4172 * Allocate a return stack for the idle task. May be the first
4173 * time through, or it may be done by CPU hotplug online.
4174 */
4175 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4176 {
4177 t->curr_ret_stack = -1;
4178 /*
4179 * The idle task has no parent, it either has its own
4180 * stack or no stack at all.
4181 */
4182 if (t->ret_stack)
4183 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4184
4185 if (ftrace_graph_active) {
4186 struct ftrace_ret_stack *ret_stack;
4187
4188 ret_stack = per_cpu(idle_ret_stack, cpu);
4189 if (!ret_stack) {
4190 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4191 * sizeof(struct ftrace_ret_stack),
4192 GFP_KERNEL);
4193 if (!ret_stack)
4194 return;
4195 per_cpu(idle_ret_stack, cpu) = ret_stack;
4196 }
4197 graph_init_task(t, ret_stack);
4198 }
4199 }
4200
4201 /* Allocate a return stack for newly created task */
4202 void ftrace_graph_init_task(struct task_struct *t)
4203 {
4204 /* Make sure we do not use the parent ret_stack */
4205 t->ret_stack = NULL;
4206 t->curr_ret_stack = -1;
4207
4208 if (ftrace_graph_active) {
4209 struct ftrace_ret_stack *ret_stack;
4210
4211 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4212 * sizeof(struct ftrace_ret_stack),
4213 GFP_KERNEL);
4214 if (!ret_stack)
4215 return;
4216 graph_init_task(t, ret_stack);
4217 }
4218 }
4219
4220 void ftrace_graph_exit_task(struct task_struct *t)
4221 {
4222 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4223
4224 t->ret_stack = NULL;
4225 /* NULL must become visible to IRQs before we free it: */
4226 barrier();
4227
4228 kfree(ret_stack);
4229 }
4230
4231 void ftrace_graph_stop(void)
4232 {
4233 ftrace_stop();
4234 }
4235 #endif