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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/bsearch.h>
26#include <linux/module.h>
27#include <linux/ftrace.h>
28#include <linux/sysctl.h>
29#include <linux/slab.h>
30#include <linux/ctype.h>
31#include <linux/sort.h>
32#include <linux/list.h>
33#include <linux/hash.h>
34#include <linux/rcupdate.h>
35
36#include <trace/events/sched.h>
37
38#include <asm/setup.h>
39
40#include "trace_output.h"
41#include "trace_stat.h"
42
43#define FTRACE_WARN_ON(cond) \
44 ({ \
45 int ___r = cond; \
46 if (WARN_ON(___r)) \
47 ftrace_kill(); \
48 ___r; \
49 })
50
51#define FTRACE_WARN_ON_ONCE(cond) \
52 ({ \
53 int ___r = cond; \
54 if (WARN_ON_ONCE(___r)) \
55 ftrace_kill(); \
56 ___r; \
57 })
58
59/* hash bits for specific function selection */
60#define FTRACE_HASH_BITS 7
61#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62#define FTRACE_HASH_DEFAULT_BITS 10
63#define FTRACE_HASH_MAX_BITS 12
64
65#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
66
67/* ftrace_enabled is a method to turn ftrace on or off */
68int ftrace_enabled __read_mostly;
69static int last_ftrace_enabled;
70
71/* Quick disabling of function tracer. */
72int function_trace_stop;
73
74/* List for set_ftrace_pid's pids. */
75LIST_HEAD(ftrace_pids);
76struct ftrace_pid {
77 struct list_head list;
78 struct pid *pid;
79};
80
81/*
82 * ftrace_disabled is set when an anomaly is discovered.
83 * ftrace_disabled is much stronger than ftrace_enabled.
84 */
85static int ftrace_disabled __read_mostly;
86
87static DEFINE_MUTEX(ftrace_lock);
88
89static struct ftrace_ops ftrace_list_end __read_mostly = {
90 .func = ftrace_stub,
91};
92
93static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
94static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
95static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
96ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
97static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
98ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
99ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
100static struct ftrace_ops global_ops;
101static struct ftrace_ops control_ops;
102
103static void
104ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
105
106/*
107 * Traverse the ftrace_global_list, invoking all entries. The reason that we
108 * can use rcu_dereference_raw() is that elements removed from this list
109 * are simply leaked, so there is no need to interact with a grace-period
110 * mechanism. The rcu_dereference_raw() calls are needed to handle
111 * concurrent insertions into the ftrace_global_list.
112 *
113 * Silly Alpha and silly pointer-speculation compiler optimizations!
114 */
115static void ftrace_global_list_func(unsigned long ip,
116 unsigned long parent_ip)
117{
118 struct ftrace_ops *op;
119
120 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
121 return;
122
123 trace_recursion_set(TRACE_GLOBAL_BIT);
124 op = rcu_dereference_raw(ftrace_global_list); /*see above*/
125 while (op != &ftrace_list_end) {
126 op->func(ip, parent_ip);
127 op = rcu_dereference_raw(op->next); /*see above*/
128 };
129 trace_recursion_clear(TRACE_GLOBAL_BIT);
130}
131
132static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
133{
134 if (!test_tsk_trace_trace(current))
135 return;
136
137 ftrace_pid_function(ip, parent_ip);
138}
139
140static void set_ftrace_pid_function(ftrace_func_t func)
141{
142 /* do not set ftrace_pid_function to itself! */
143 if (func != ftrace_pid_func)
144 ftrace_pid_function = func;
145}
146
147/**
148 * clear_ftrace_function - reset the ftrace function
149 *
150 * This NULLs the ftrace function and in essence stops
151 * tracing. There may be lag
152 */
153void clear_ftrace_function(void)
154{
155 ftrace_trace_function = ftrace_stub;
156 __ftrace_trace_function = ftrace_stub;
157 __ftrace_trace_function_delay = ftrace_stub;
158 ftrace_pid_function = ftrace_stub;
159}
160
161#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
162/*
163 * For those archs that do not test ftrace_trace_stop in their
164 * mcount call site, we need to do it from C.
165 */
166static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
167{
168 if (function_trace_stop)
169 return;
170
171 __ftrace_trace_function(ip, parent_ip);
172}
173#endif
174
175static void control_ops_disable_all(struct ftrace_ops *ops)
176{
177 int cpu;
178
179 for_each_possible_cpu(cpu)
180 *per_cpu_ptr(ops->disabled, cpu) = 1;
181}
182
183static int control_ops_alloc(struct ftrace_ops *ops)
184{
185 int __percpu *disabled;
186
187 disabled = alloc_percpu(int);
188 if (!disabled)
189 return -ENOMEM;
190
191 ops->disabled = disabled;
192 control_ops_disable_all(ops);
193 return 0;
194}
195
196static void control_ops_free(struct ftrace_ops *ops)
197{
198 free_percpu(ops->disabled);
199}
200
201static void update_global_ops(void)
202{
203 ftrace_func_t func;
204
205 /*
206 * If there's only one function registered, then call that
207 * function directly. Otherwise, we need to iterate over the
208 * registered callers.
209 */
210 if (ftrace_global_list == &ftrace_list_end ||
211 ftrace_global_list->next == &ftrace_list_end)
212 func = ftrace_global_list->func;
213 else
214 func = ftrace_global_list_func;
215
216 /* If we filter on pids, update to use the pid function */
217 if (!list_empty(&ftrace_pids)) {
218 set_ftrace_pid_function(func);
219 func = ftrace_pid_func;
220 }
221
222 global_ops.func = func;
223}
224
225static void update_ftrace_function(void)
226{
227 ftrace_func_t func;
228
229 update_global_ops();
230
231 /*
232 * If we are at the end of the list and this ops is
233 * not dynamic, then have the mcount trampoline call
234 * the function directly
235 */
236 if (ftrace_ops_list == &ftrace_list_end ||
237 (ftrace_ops_list->next == &ftrace_list_end &&
238 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
239 func = ftrace_ops_list->func;
240 else
241 func = ftrace_ops_list_func;
242
243#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
244 ftrace_trace_function = func;
245#else
246#ifdef CONFIG_DYNAMIC_FTRACE
247 /* do not update till all functions have been modified */
248 __ftrace_trace_function_delay = func;
249#else
250 __ftrace_trace_function = func;
251#endif
252 ftrace_trace_function =
253 (func == ftrace_stub) ? func : ftrace_test_stop_func;
254#endif
255}
256
257static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
258{
259 ops->next = *list;
260 /*
261 * We are entering ops into the list but another
262 * CPU might be walking that list. We need to make sure
263 * the ops->next pointer is valid before another CPU sees
264 * the ops pointer included into the list.
265 */
266 rcu_assign_pointer(*list, ops);
267}
268
269static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
270{
271 struct ftrace_ops **p;
272
273 /*
274 * If we are removing the last function, then simply point
275 * to the ftrace_stub.
276 */
277 if (*list == ops && ops->next == &ftrace_list_end) {
278 *list = &ftrace_list_end;
279 return 0;
280 }
281
282 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
283 if (*p == ops)
284 break;
285
286 if (*p != ops)
287 return -1;
288
289 *p = (*p)->next;
290 return 0;
291}
292
293static void add_ftrace_list_ops(struct ftrace_ops **list,
294 struct ftrace_ops *main_ops,
295 struct ftrace_ops *ops)
296{
297 int first = *list == &ftrace_list_end;
298 add_ftrace_ops(list, ops);
299 if (first)
300 add_ftrace_ops(&ftrace_ops_list, main_ops);
301}
302
303static int remove_ftrace_list_ops(struct ftrace_ops **list,
304 struct ftrace_ops *main_ops,
305 struct ftrace_ops *ops)
306{
307 int ret = remove_ftrace_ops(list, ops);
308 if (!ret && *list == &ftrace_list_end)
309 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
310 return ret;
311}
312
313static int __register_ftrace_function(struct ftrace_ops *ops)
314{
315 if (ftrace_disabled)
316 return -ENODEV;
317
318 if (FTRACE_WARN_ON(ops == &global_ops))
319 return -EINVAL;
320
321 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
322 return -EBUSY;
323
324 /* We don't support both control and global flags set. */
325 if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
326 return -EINVAL;
327
328 if (!core_kernel_data((unsigned long)ops))
329 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
330
331 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
332 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
333 ops->flags |= FTRACE_OPS_FL_ENABLED;
334 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
335 if (control_ops_alloc(ops))
336 return -ENOMEM;
337 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
338 } else
339 add_ftrace_ops(&ftrace_ops_list, ops);
340
341 if (ftrace_enabled)
342 update_ftrace_function();
343
344 return 0;
345}
346
347static int __unregister_ftrace_function(struct ftrace_ops *ops)
348{
349 int ret;
350
351 if (ftrace_disabled)
352 return -ENODEV;
353
354 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
355 return -EBUSY;
356
357 if (FTRACE_WARN_ON(ops == &global_ops))
358 return -EINVAL;
359
360 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
361 ret = remove_ftrace_list_ops(&ftrace_global_list,
362 &global_ops, ops);
363 if (!ret)
364 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
365 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
366 ret = remove_ftrace_list_ops(&ftrace_control_list,
367 &control_ops, ops);
368 if (!ret) {
369 /*
370 * The ftrace_ops is now removed from the list,
371 * so there'll be no new users. We must ensure
372 * all current users are done before we free
373 * the control data.
374 */
375 synchronize_sched();
376 control_ops_free(ops);
377 }
378 } else
379 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
380
381 if (ret < 0)
382 return ret;
383
384 if (ftrace_enabled)
385 update_ftrace_function();
386
387 /*
388 * Dynamic ops may be freed, we must make sure that all
389 * callers are done before leaving this function.
390 */
391 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
392 synchronize_sched();
393
394 return 0;
395}
396
397static void ftrace_update_pid_func(void)
398{
399 /* Only do something if we are tracing something */
400 if (ftrace_trace_function == ftrace_stub)
401 return;
402
403 update_ftrace_function();
404}
405
406#ifdef CONFIG_FUNCTION_PROFILER
407struct ftrace_profile {
408 struct hlist_node node;
409 unsigned long ip;
410 unsigned long counter;
411#ifdef CONFIG_FUNCTION_GRAPH_TRACER
412 unsigned long long time;
413 unsigned long long time_squared;
414#endif
415};
416
417struct ftrace_profile_page {
418 struct ftrace_profile_page *next;
419 unsigned long index;
420 struct ftrace_profile records[];
421};
422
423struct ftrace_profile_stat {
424 atomic_t disabled;
425 struct hlist_head *hash;
426 struct ftrace_profile_page *pages;
427 struct ftrace_profile_page *start;
428 struct tracer_stat stat;
429};
430
431#define PROFILE_RECORDS_SIZE \
432 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
433
434#define PROFILES_PER_PAGE \
435 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
436
437static int ftrace_profile_bits __read_mostly;
438static int ftrace_profile_enabled __read_mostly;
439
440/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
441static DEFINE_MUTEX(ftrace_profile_lock);
442
443static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
444
445#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
446
447static void *
448function_stat_next(void *v, int idx)
449{
450 struct ftrace_profile *rec = v;
451 struct ftrace_profile_page *pg;
452
453 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
454
455 again:
456 if (idx != 0)
457 rec++;
458
459 if ((void *)rec >= (void *)&pg->records[pg->index]) {
460 pg = pg->next;
461 if (!pg)
462 return NULL;
463 rec = &pg->records[0];
464 if (!rec->counter)
465 goto again;
466 }
467
468 return rec;
469}
470
471static void *function_stat_start(struct tracer_stat *trace)
472{
473 struct ftrace_profile_stat *stat =
474 container_of(trace, struct ftrace_profile_stat, stat);
475
476 if (!stat || !stat->start)
477 return NULL;
478
479 return function_stat_next(&stat->start->records[0], 0);
480}
481
482#ifdef CONFIG_FUNCTION_GRAPH_TRACER
483/* function graph compares on total time */
484static int function_stat_cmp(void *p1, void *p2)
485{
486 struct ftrace_profile *a = p1;
487 struct ftrace_profile *b = p2;
488
489 if (a->time < b->time)
490 return -1;
491 if (a->time > b->time)
492 return 1;
493 else
494 return 0;
495}
496#else
497/* not function graph compares against hits */
498static int function_stat_cmp(void *p1, void *p2)
499{
500 struct ftrace_profile *a = p1;
501 struct ftrace_profile *b = p2;
502
503 if (a->counter < b->counter)
504 return -1;
505 if (a->counter > b->counter)
506 return 1;
507 else
508 return 0;
509}
510#endif
511
512static int function_stat_headers(struct seq_file *m)
513{
514#ifdef CONFIG_FUNCTION_GRAPH_TRACER
515 seq_printf(m, " Function "
516 "Hit Time Avg s^2\n"
517 " -------- "
518 "--- ---- --- ---\n");
519#else
520 seq_printf(m, " Function Hit\n"
521 " -------- ---\n");
522#endif
523 return 0;
524}
525
526static int function_stat_show(struct seq_file *m, void *v)
527{
528 struct ftrace_profile *rec = v;
529 char str[KSYM_SYMBOL_LEN];
530 int ret = 0;
531#ifdef CONFIG_FUNCTION_GRAPH_TRACER
532 static struct trace_seq s;
533 unsigned long long avg;
534 unsigned long long stddev;
535#endif
536 mutex_lock(&ftrace_profile_lock);
537
538 /* we raced with function_profile_reset() */
539 if (unlikely(rec->counter == 0)) {
540 ret = -EBUSY;
541 goto out;
542 }
543
544 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
545 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
546
547#ifdef CONFIG_FUNCTION_GRAPH_TRACER
548 seq_printf(m, " ");
549 avg = rec->time;
550 do_div(avg, rec->counter);
551
552 /* Sample standard deviation (s^2) */
553 if (rec->counter <= 1)
554 stddev = 0;
555 else {
556 stddev = rec->time_squared - rec->counter * avg * avg;
557 /*
558 * Divide only 1000 for ns^2 -> us^2 conversion.
559 * trace_print_graph_duration will divide 1000 again.
560 */
561 do_div(stddev, (rec->counter - 1) * 1000);
562 }
563
564 trace_seq_init(&s);
565 trace_print_graph_duration(rec->time, &s);
566 trace_seq_puts(&s, " ");
567 trace_print_graph_duration(avg, &s);
568 trace_seq_puts(&s, " ");
569 trace_print_graph_duration(stddev, &s);
570 trace_print_seq(m, &s);
571#endif
572 seq_putc(m, '\n');
573out:
574 mutex_unlock(&ftrace_profile_lock);
575
576 return ret;
577}
578
579static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
580{
581 struct ftrace_profile_page *pg;
582
583 pg = stat->pages = stat->start;
584
585 while (pg) {
586 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
587 pg->index = 0;
588 pg = pg->next;
589 }
590
591 memset(stat->hash, 0,
592 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
593}
594
595int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
596{
597 struct ftrace_profile_page *pg;
598 int functions;
599 int pages;
600 int i;
601
602 /* If we already allocated, do nothing */
603 if (stat->pages)
604 return 0;
605
606 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
607 if (!stat->pages)
608 return -ENOMEM;
609
610#ifdef CONFIG_DYNAMIC_FTRACE
611 functions = ftrace_update_tot_cnt;
612#else
613 /*
614 * We do not know the number of functions that exist because
615 * dynamic tracing is what counts them. With past experience
616 * we have around 20K functions. That should be more than enough.
617 * It is highly unlikely we will execute every function in
618 * the kernel.
619 */
620 functions = 20000;
621#endif
622
623 pg = stat->start = stat->pages;
624
625 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
626
627 for (i = 0; i < pages; i++) {
628 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
629 if (!pg->next)
630 goto out_free;
631 pg = pg->next;
632 }
633
634 return 0;
635
636 out_free:
637 pg = stat->start;
638 while (pg) {
639 unsigned long tmp = (unsigned long)pg;
640
641 pg = pg->next;
642 free_page(tmp);
643 }
644
645 free_page((unsigned long)stat->pages);
646 stat->pages = NULL;
647 stat->start = NULL;
648
649 return -ENOMEM;
650}
651
652static int ftrace_profile_init_cpu(int cpu)
653{
654 struct ftrace_profile_stat *stat;
655 int size;
656
657 stat = &per_cpu(ftrace_profile_stats, cpu);
658
659 if (stat->hash) {
660 /* If the profile is already created, simply reset it */
661 ftrace_profile_reset(stat);
662 return 0;
663 }
664
665 /*
666 * We are profiling all functions, but usually only a few thousand
667 * functions are hit. We'll make a hash of 1024 items.
668 */
669 size = FTRACE_PROFILE_HASH_SIZE;
670
671 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
672
673 if (!stat->hash)
674 return -ENOMEM;
675
676 if (!ftrace_profile_bits) {
677 size--;
678
679 for (; size; size >>= 1)
680 ftrace_profile_bits++;
681 }
682
683 /* Preallocate the function profiling pages */
684 if (ftrace_profile_pages_init(stat) < 0) {
685 kfree(stat->hash);
686 stat->hash = NULL;
687 return -ENOMEM;
688 }
689
690 return 0;
691}
692
693static int ftrace_profile_init(void)
694{
695 int cpu;
696 int ret = 0;
697
698 for_each_online_cpu(cpu) {
699 ret = ftrace_profile_init_cpu(cpu);
700 if (ret)
701 break;
702 }
703
704 return ret;
705}
706
707/* interrupts must be disabled */
708static struct ftrace_profile *
709ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
710{
711 struct ftrace_profile *rec;
712 struct hlist_head *hhd;
713 struct hlist_node *n;
714 unsigned long key;
715
716 key = hash_long(ip, ftrace_profile_bits);
717 hhd = &stat->hash[key];
718
719 if (hlist_empty(hhd))
720 return NULL;
721
722 hlist_for_each_entry_rcu(rec, n, hhd, node) {
723 if (rec->ip == ip)
724 return rec;
725 }
726
727 return NULL;
728}
729
730static void ftrace_add_profile(struct ftrace_profile_stat *stat,
731 struct ftrace_profile *rec)
732{
733 unsigned long key;
734
735 key = hash_long(rec->ip, ftrace_profile_bits);
736 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
737}
738
739/*
740 * The memory is already allocated, this simply finds a new record to use.
741 */
742static struct ftrace_profile *
743ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
744{
745 struct ftrace_profile *rec = NULL;
746
747 /* prevent recursion (from NMIs) */
748 if (atomic_inc_return(&stat->disabled) != 1)
749 goto out;
750
751 /*
752 * Try to find the function again since an NMI
753 * could have added it
754 */
755 rec = ftrace_find_profiled_func(stat, ip);
756 if (rec)
757 goto out;
758
759 if (stat->pages->index == PROFILES_PER_PAGE) {
760 if (!stat->pages->next)
761 goto out;
762 stat->pages = stat->pages->next;
763 }
764
765 rec = &stat->pages->records[stat->pages->index++];
766 rec->ip = ip;
767 ftrace_add_profile(stat, rec);
768
769 out:
770 atomic_dec(&stat->disabled);
771
772 return rec;
773}
774
775static void
776function_profile_call(unsigned long ip, unsigned long parent_ip)
777{
778 struct ftrace_profile_stat *stat;
779 struct ftrace_profile *rec;
780 unsigned long flags;
781
782 if (!ftrace_profile_enabled)
783 return;
784
785 local_irq_save(flags);
786
787 stat = &__get_cpu_var(ftrace_profile_stats);
788 if (!stat->hash || !ftrace_profile_enabled)
789 goto out;
790
791 rec = ftrace_find_profiled_func(stat, ip);
792 if (!rec) {
793 rec = ftrace_profile_alloc(stat, ip);
794 if (!rec)
795 goto out;
796 }
797
798 rec->counter++;
799 out:
800 local_irq_restore(flags);
801}
802
803#ifdef CONFIG_FUNCTION_GRAPH_TRACER
804static int profile_graph_entry(struct ftrace_graph_ent *trace)
805{
806 function_profile_call(trace->func, 0);
807 return 1;
808}
809
810static void profile_graph_return(struct ftrace_graph_ret *trace)
811{
812 struct ftrace_profile_stat *stat;
813 unsigned long long calltime;
814 struct ftrace_profile *rec;
815 unsigned long flags;
816
817 local_irq_save(flags);
818 stat = &__get_cpu_var(ftrace_profile_stats);
819 if (!stat->hash || !ftrace_profile_enabled)
820 goto out;
821
822 /* If the calltime was zero'd ignore it */
823 if (!trace->calltime)
824 goto out;
825
826 calltime = trace->rettime - trace->calltime;
827
828 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
829 int index;
830
831 index = trace->depth;
832
833 /* Append this call time to the parent time to subtract */
834 if (index)
835 current->ret_stack[index - 1].subtime += calltime;
836
837 if (current->ret_stack[index].subtime < calltime)
838 calltime -= current->ret_stack[index].subtime;
839 else
840 calltime = 0;
841 }
842
843 rec = ftrace_find_profiled_func(stat, trace->func);
844 if (rec) {
845 rec->time += calltime;
846 rec->time_squared += calltime * calltime;
847 }
848
849 out:
850 local_irq_restore(flags);
851}
852
853static int register_ftrace_profiler(void)
854{
855 return register_ftrace_graph(&profile_graph_return,
856 &profile_graph_entry);
857}
858
859static void unregister_ftrace_profiler(void)
860{
861 unregister_ftrace_graph();
862}
863#else
864static struct ftrace_ops ftrace_profile_ops __read_mostly = {
865 .func = function_profile_call,
866};
867
868static int register_ftrace_profiler(void)
869{
870 return register_ftrace_function(&ftrace_profile_ops);
871}
872
873static void unregister_ftrace_profiler(void)
874{
875 unregister_ftrace_function(&ftrace_profile_ops);
876}
877#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
878
879static ssize_t
880ftrace_profile_write(struct file *filp, const char __user *ubuf,
881 size_t cnt, loff_t *ppos)
882{
883 unsigned long val;
884 int ret;
885
886 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
887 if (ret)
888 return ret;
889
890 val = !!val;
891
892 mutex_lock(&ftrace_profile_lock);
893 if (ftrace_profile_enabled ^ val) {
894 if (val) {
895 ret = ftrace_profile_init();
896 if (ret < 0) {
897 cnt = ret;
898 goto out;
899 }
900
901 ret = register_ftrace_profiler();
902 if (ret < 0) {
903 cnt = ret;
904 goto out;
905 }
906 ftrace_profile_enabled = 1;
907 } else {
908 ftrace_profile_enabled = 0;
909 /*
910 * unregister_ftrace_profiler calls stop_machine
911 * so this acts like an synchronize_sched.
912 */
913 unregister_ftrace_profiler();
914 }
915 }
916 out:
917 mutex_unlock(&ftrace_profile_lock);
918
919 *ppos += cnt;
920
921 return cnt;
922}
923
924static ssize_t
925ftrace_profile_read(struct file *filp, char __user *ubuf,
926 size_t cnt, loff_t *ppos)
927{
928 char buf[64]; /* big enough to hold a number */
929 int r;
930
931 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
932 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
933}
934
935static const struct file_operations ftrace_profile_fops = {
936 .open = tracing_open_generic,
937 .read = ftrace_profile_read,
938 .write = ftrace_profile_write,
939 .llseek = default_llseek,
940};
941
942/* used to initialize the real stat files */
943static struct tracer_stat function_stats __initdata = {
944 .name = "functions",
945 .stat_start = function_stat_start,
946 .stat_next = function_stat_next,
947 .stat_cmp = function_stat_cmp,
948 .stat_headers = function_stat_headers,
949 .stat_show = function_stat_show
950};
951
952static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
953{
954 struct ftrace_profile_stat *stat;
955 struct dentry *entry;
956 char *name;
957 int ret;
958 int cpu;
959
960 for_each_possible_cpu(cpu) {
961 stat = &per_cpu(ftrace_profile_stats, cpu);
962
963 /* allocate enough for function name + cpu number */
964 name = kmalloc(32, GFP_KERNEL);
965 if (!name) {
966 /*
967 * The files created are permanent, if something happens
968 * we still do not free memory.
969 */
970 WARN(1,
971 "Could not allocate stat file for cpu %d\n",
972 cpu);
973 return;
974 }
975 stat->stat = function_stats;
976 snprintf(name, 32, "function%d", cpu);
977 stat->stat.name = name;
978 ret = register_stat_tracer(&stat->stat);
979 if (ret) {
980 WARN(1,
981 "Could not register function stat for cpu %d\n",
982 cpu);
983 kfree(name);
984 return;
985 }
986 }
987
988 entry = debugfs_create_file("function_profile_enabled", 0644,
989 d_tracer, NULL, &ftrace_profile_fops);
990 if (!entry)
991 pr_warning("Could not create debugfs "
992 "'function_profile_enabled' entry\n");
993}
994
995#else /* CONFIG_FUNCTION_PROFILER */
996static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
997{
998}
999#endif /* CONFIG_FUNCTION_PROFILER */
1000
1001static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1002
1003#ifdef CONFIG_DYNAMIC_FTRACE
1004
1005#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1006# error Dynamic ftrace depends on MCOUNT_RECORD
1007#endif
1008
1009static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1010
1011struct ftrace_func_probe {
1012 struct hlist_node node;
1013 struct ftrace_probe_ops *ops;
1014 unsigned long flags;
1015 unsigned long ip;
1016 void *data;
1017 struct rcu_head rcu;
1018};
1019
1020struct ftrace_func_entry {
1021 struct hlist_node hlist;
1022 unsigned long ip;
1023};
1024
1025struct ftrace_hash {
1026 unsigned long size_bits;
1027 struct hlist_head *buckets;
1028 unsigned long count;
1029 struct rcu_head rcu;
1030};
1031
1032/*
1033 * We make these constant because no one should touch them,
1034 * but they are used as the default "empty hash", to avoid allocating
1035 * it all the time. These are in a read only section such that if
1036 * anyone does try to modify it, it will cause an exception.
1037 */
1038static const struct hlist_head empty_buckets[1];
1039static const struct ftrace_hash empty_hash = {
1040 .buckets = (struct hlist_head *)empty_buckets,
1041};
1042#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1043
1044static struct ftrace_ops global_ops = {
1045 .func = ftrace_stub,
1046 .notrace_hash = EMPTY_HASH,
1047 .filter_hash = EMPTY_HASH,
1048};
1049
1050static DEFINE_MUTEX(ftrace_regex_lock);
1051
1052struct ftrace_page {
1053 struct ftrace_page *next;
1054 struct dyn_ftrace *records;
1055 int index;
1056 int size;
1057};
1058
1059static struct ftrace_page *ftrace_new_pgs;
1060
1061#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1062#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1063
1064/* estimate from running different kernels */
1065#define NR_TO_INIT 10000
1066
1067static struct ftrace_page *ftrace_pages_start;
1068static struct ftrace_page *ftrace_pages;
1069
1070static bool ftrace_hash_empty(struct ftrace_hash *hash)
1071{
1072 return !hash || !hash->count;
1073}
1074
1075static struct ftrace_func_entry *
1076ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1077{
1078 unsigned long key;
1079 struct ftrace_func_entry *entry;
1080 struct hlist_head *hhd;
1081 struct hlist_node *n;
1082
1083 if (ftrace_hash_empty(hash))
1084 return NULL;
1085
1086 if (hash->size_bits > 0)
1087 key = hash_long(ip, hash->size_bits);
1088 else
1089 key = 0;
1090
1091 hhd = &hash->buckets[key];
1092
1093 hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1094 if (entry->ip == ip)
1095 return entry;
1096 }
1097 return NULL;
1098}
1099
1100static void __add_hash_entry(struct ftrace_hash *hash,
1101 struct ftrace_func_entry *entry)
1102{
1103 struct hlist_head *hhd;
1104 unsigned long key;
1105
1106 if (hash->size_bits)
1107 key = hash_long(entry->ip, hash->size_bits);
1108 else
1109 key = 0;
1110
1111 hhd = &hash->buckets[key];
1112 hlist_add_head(&entry->hlist, hhd);
1113 hash->count++;
1114}
1115
1116static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1117{
1118 struct ftrace_func_entry *entry;
1119
1120 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1121 if (!entry)
1122 return -ENOMEM;
1123
1124 entry->ip = ip;
1125 __add_hash_entry(hash, entry);
1126
1127 return 0;
1128}
1129
1130static void
1131free_hash_entry(struct ftrace_hash *hash,
1132 struct ftrace_func_entry *entry)
1133{
1134 hlist_del(&entry->hlist);
1135 kfree(entry);
1136 hash->count--;
1137}
1138
1139static void
1140remove_hash_entry(struct ftrace_hash *hash,
1141 struct ftrace_func_entry *entry)
1142{
1143 hlist_del(&entry->hlist);
1144 hash->count--;
1145}
1146
1147static void ftrace_hash_clear(struct ftrace_hash *hash)
1148{
1149 struct hlist_head *hhd;
1150 struct hlist_node *tp, *tn;
1151 struct ftrace_func_entry *entry;
1152 int size = 1 << hash->size_bits;
1153 int i;
1154
1155 if (!hash->count)
1156 return;
1157
1158 for (i = 0; i < size; i++) {
1159 hhd = &hash->buckets[i];
1160 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1161 free_hash_entry(hash, entry);
1162 }
1163 FTRACE_WARN_ON(hash->count);
1164}
1165
1166static void free_ftrace_hash(struct ftrace_hash *hash)
1167{
1168 if (!hash || hash == EMPTY_HASH)
1169 return;
1170 ftrace_hash_clear(hash);
1171 kfree(hash->buckets);
1172 kfree(hash);
1173}
1174
1175static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1176{
1177 struct ftrace_hash *hash;
1178
1179 hash = container_of(rcu, struct ftrace_hash, rcu);
1180 free_ftrace_hash(hash);
1181}
1182
1183static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1184{
1185 if (!hash || hash == EMPTY_HASH)
1186 return;
1187 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1188}
1189
1190void ftrace_free_filter(struct ftrace_ops *ops)
1191{
1192 free_ftrace_hash(ops->filter_hash);
1193 free_ftrace_hash(ops->notrace_hash);
1194}
1195
1196static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1197{
1198 struct ftrace_hash *hash;
1199 int size;
1200
1201 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1202 if (!hash)
1203 return NULL;
1204
1205 size = 1 << size_bits;
1206 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1207
1208 if (!hash->buckets) {
1209 kfree(hash);
1210 return NULL;
1211 }
1212
1213 hash->size_bits = size_bits;
1214
1215 return hash;
1216}
1217
1218static struct ftrace_hash *
1219alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1220{
1221 struct ftrace_func_entry *entry;
1222 struct ftrace_hash *new_hash;
1223 struct hlist_node *tp;
1224 int size;
1225 int ret;
1226 int i;
1227
1228 new_hash = alloc_ftrace_hash(size_bits);
1229 if (!new_hash)
1230 return NULL;
1231
1232 /* Empty hash? */
1233 if (ftrace_hash_empty(hash))
1234 return new_hash;
1235
1236 size = 1 << hash->size_bits;
1237 for (i = 0; i < size; i++) {
1238 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1239 ret = add_hash_entry(new_hash, entry->ip);
1240 if (ret < 0)
1241 goto free_hash;
1242 }
1243 }
1244
1245 FTRACE_WARN_ON(new_hash->count != hash->count);
1246
1247 return new_hash;
1248
1249 free_hash:
1250 free_ftrace_hash(new_hash);
1251 return NULL;
1252}
1253
1254static void
1255ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1256static void
1257ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1258
1259static int
1260ftrace_hash_move(struct ftrace_ops *ops, int enable,
1261 struct ftrace_hash **dst, struct ftrace_hash *src)
1262{
1263 struct ftrace_func_entry *entry;
1264 struct hlist_node *tp, *tn;
1265 struct hlist_head *hhd;
1266 struct ftrace_hash *old_hash;
1267 struct ftrace_hash *new_hash;
1268 unsigned long key;
1269 int size = src->count;
1270 int bits = 0;
1271 int ret;
1272 int i;
1273
1274 /*
1275 * Remove the current set, update the hash and add
1276 * them back.
1277 */
1278 ftrace_hash_rec_disable(ops, enable);
1279
1280 /*
1281 * If the new source is empty, just free dst and assign it
1282 * the empty_hash.
1283 */
1284 if (!src->count) {
1285 free_ftrace_hash_rcu(*dst);
1286 rcu_assign_pointer(*dst, EMPTY_HASH);
1287 /* still need to update the function records */
1288 ret = 0;
1289 goto out;
1290 }
1291
1292 /*
1293 * Make the hash size about 1/2 the # found
1294 */
1295 for (size /= 2; size; size >>= 1)
1296 bits++;
1297
1298 /* Don't allocate too much */
1299 if (bits > FTRACE_HASH_MAX_BITS)
1300 bits = FTRACE_HASH_MAX_BITS;
1301
1302 ret = -ENOMEM;
1303 new_hash = alloc_ftrace_hash(bits);
1304 if (!new_hash)
1305 goto out;
1306
1307 size = 1 << src->size_bits;
1308 for (i = 0; i < size; i++) {
1309 hhd = &src->buckets[i];
1310 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1311 if (bits > 0)
1312 key = hash_long(entry->ip, bits);
1313 else
1314 key = 0;
1315 remove_hash_entry(src, entry);
1316 __add_hash_entry(new_hash, entry);
1317 }
1318 }
1319
1320 old_hash = *dst;
1321 rcu_assign_pointer(*dst, new_hash);
1322 free_ftrace_hash_rcu(old_hash);
1323
1324 ret = 0;
1325 out:
1326 /*
1327 * Enable regardless of ret:
1328 * On success, we enable the new hash.
1329 * On failure, we re-enable the original hash.
1330 */
1331 ftrace_hash_rec_enable(ops, enable);
1332
1333 return ret;
1334}
1335
1336/*
1337 * Test the hashes for this ops to see if we want to call
1338 * the ops->func or not.
1339 *
1340 * It's a match if the ip is in the ops->filter_hash or
1341 * the filter_hash does not exist or is empty,
1342 * AND
1343 * the ip is not in the ops->notrace_hash.
1344 *
1345 * This needs to be called with preemption disabled as
1346 * the hashes are freed with call_rcu_sched().
1347 */
1348static int
1349ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1350{
1351 struct ftrace_hash *filter_hash;
1352 struct ftrace_hash *notrace_hash;
1353 int ret;
1354
1355 filter_hash = rcu_dereference_raw(ops->filter_hash);
1356 notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1357
1358 if ((ftrace_hash_empty(filter_hash) ||
1359 ftrace_lookup_ip(filter_hash, ip)) &&
1360 (ftrace_hash_empty(notrace_hash) ||
1361 !ftrace_lookup_ip(notrace_hash, ip)))
1362 ret = 1;
1363 else
1364 ret = 0;
1365
1366 return ret;
1367}
1368
1369/*
1370 * This is a double for. Do not use 'break' to break out of the loop,
1371 * you must use a goto.
1372 */
1373#define do_for_each_ftrace_rec(pg, rec) \
1374 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1375 int _____i; \
1376 for (_____i = 0; _____i < pg->index; _____i++) { \
1377 rec = &pg->records[_____i];
1378
1379#define while_for_each_ftrace_rec() \
1380 } \
1381 }
1382
1383
1384static int ftrace_cmp_recs(const void *a, const void *b)
1385{
1386 const struct dyn_ftrace *key = a;
1387 const struct dyn_ftrace *rec = b;
1388
1389 if (key->flags < rec->ip)
1390 return -1;
1391 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1392 return 1;
1393 return 0;
1394}
1395
1396static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1397{
1398 struct ftrace_page *pg;
1399 struct dyn_ftrace *rec;
1400 struct dyn_ftrace key;
1401
1402 key.ip = start;
1403 key.flags = end; /* overload flags, as it is unsigned long */
1404
1405 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1406 if (end < pg->records[0].ip ||
1407 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1408 continue;
1409 rec = bsearch(&key, pg->records, pg->index,
1410 sizeof(struct dyn_ftrace),
1411 ftrace_cmp_recs);
1412 if (rec)
1413 return rec->ip;
1414 }
1415
1416 return 0;
1417}
1418
1419/**
1420 * ftrace_location - return true if the ip giving is a traced location
1421 * @ip: the instruction pointer to check
1422 *
1423 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1424 * That is, the instruction that is either a NOP or call to
1425 * the function tracer. It checks the ftrace internal tables to
1426 * determine if the address belongs or not.
1427 */
1428unsigned long ftrace_location(unsigned long ip)
1429{
1430 return ftrace_location_range(ip, ip);
1431}
1432
1433/**
1434 * ftrace_text_reserved - return true if range contains an ftrace location
1435 * @start: start of range to search
1436 * @end: end of range to search (inclusive). @end points to the last byte to check.
1437 *
1438 * Returns 1 if @start and @end contains a ftrace location.
1439 * That is, the instruction that is either a NOP or call to
1440 * the function tracer. It checks the ftrace internal tables to
1441 * determine if the address belongs or not.
1442 */
1443int ftrace_text_reserved(void *start, void *end)
1444{
1445 unsigned long ret;
1446
1447 ret = ftrace_location_range((unsigned long)start,
1448 (unsigned long)end);
1449
1450 return (int)!!ret;
1451}
1452
1453static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1454 int filter_hash,
1455 bool inc)
1456{
1457 struct ftrace_hash *hash;
1458 struct ftrace_hash *other_hash;
1459 struct ftrace_page *pg;
1460 struct dyn_ftrace *rec;
1461 int count = 0;
1462 int all = 0;
1463
1464 /* Only update if the ops has been registered */
1465 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1466 return;
1467
1468 /*
1469 * In the filter_hash case:
1470 * If the count is zero, we update all records.
1471 * Otherwise we just update the items in the hash.
1472 *
1473 * In the notrace_hash case:
1474 * We enable the update in the hash.
1475 * As disabling notrace means enabling the tracing,
1476 * and enabling notrace means disabling, the inc variable
1477 * gets inversed.
1478 */
1479 if (filter_hash) {
1480 hash = ops->filter_hash;
1481 other_hash = ops->notrace_hash;
1482 if (ftrace_hash_empty(hash))
1483 all = 1;
1484 } else {
1485 inc = !inc;
1486 hash = ops->notrace_hash;
1487 other_hash = ops->filter_hash;
1488 /*
1489 * If the notrace hash has no items,
1490 * then there's nothing to do.
1491 */
1492 if (ftrace_hash_empty(hash))
1493 return;
1494 }
1495
1496 do_for_each_ftrace_rec(pg, rec) {
1497 int in_other_hash = 0;
1498 int in_hash = 0;
1499 int match = 0;
1500
1501 if (all) {
1502 /*
1503 * Only the filter_hash affects all records.
1504 * Update if the record is not in the notrace hash.
1505 */
1506 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1507 match = 1;
1508 } else {
1509 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1510 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1511
1512 /*
1513 *
1514 */
1515 if (filter_hash && in_hash && !in_other_hash)
1516 match = 1;
1517 else if (!filter_hash && in_hash &&
1518 (in_other_hash || ftrace_hash_empty(other_hash)))
1519 match = 1;
1520 }
1521 if (!match)
1522 continue;
1523
1524 if (inc) {
1525 rec->flags++;
1526 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1527 return;
1528 } else {
1529 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1530 return;
1531 rec->flags--;
1532 }
1533 count++;
1534 /* Shortcut, if we handled all records, we are done. */
1535 if (!all && count == hash->count)
1536 return;
1537 } while_for_each_ftrace_rec();
1538}
1539
1540static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1541 int filter_hash)
1542{
1543 __ftrace_hash_rec_update(ops, filter_hash, 0);
1544}
1545
1546static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1547 int filter_hash)
1548{
1549 __ftrace_hash_rec_update(ops, filter_hash, 1);
1550}
1551
1552static void print_ip_ins(const char *fmt, unsigned char *p)
1553{
1554 int i;
1555
1556 printk(KERN_CONT "%s", fmt);
1557
1558 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1559 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1560}
1561
1562/**
1563 * ftrace_bug - report and shutdown function tracer
1564 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1565 * @ip: The address that failed
1566 *
1567 * The arch code that enables or disables the function tracing
1568 * can call ftrace_bug() when it has detected a problem in
1569 * modifying the code. @failed should be one of either:
1570 * EFAULT - if the problem happens on reading the @ip address
1571 * EINVAL - if what is read at @ip is not what was expected
1572 * EPERM - if the problem happens on writting to the @ip address
1573 */
1574void ftrace_bug(int failed, unsigned long ip)
1575{
1576 switch (failed) {
1577 case -EFAULT:
1578 FTRACE_WARN_ON_ONCE(1);
1579 pr_info("ftrace faulted on modifying ");
1580 print_ip_sym(ip);
1581 break;
1582 case -EINVAL:
1583 FTRACE_WARN_ON_ONCE(1);
1584 pr_info("ftrace failed to modify ");
1585 print_ip_sym(ip);
1586 print_ip_ins(" actual: ", (unsigned char *)ip);
1587 printk(KERN_CONT "\n");
1588 break;
1589 case -EPERM:
1590 FTRACE_WARN_ON_ONCE(1);
1591 pr_info("ftrace faulted on writing ");
1592 print_ip_sym(ip);
1593 break;
1594 default:
1595 FTRACE_WARN_ON_ONCE(1);
1596 pr_info("ftrace faulted on unknown error ");
1597 print_ip_sym(ip);
1598 }
1599}
1600
1601static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1602{
1603 unsigned long flag = 0UL;
1604
1605 /*
1606 * If we are updating calls:
1607 *
1608 * If the record has a ref count, then we need to enable it
1609 * because someone is using it.
1610 *
1611 * Otherwise we make sure its disabled.
1612 *
1613 * If we are disabling calls, then disable all records that
1614 * are enabled.
1615 */
1616 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1617 flag = FTRACE_FL_ENABLED;
1618
1619 /* If the state of this record hasn't changed, then do nothing */
1620 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1621 return FTRACE_UPDATE_IGNORE;
1622
1623 if (flag) {
1624 if (update)
1625 rec->flags |= FTRACE_FL_ENABLED;
1626 return FTRACE_UPDATE_MAKE_CALL;
1627 }
1628
1629 if (update)
1630 rec->flags &= ~FTRACE_FL_ENABLED;
1631
1632 return FTRACE_UPDATE_MAKE_NOP;
1633}
1634
1635/**
1636 * ftrace_update_record, set a record that now is tracing or not
1637 * @rec: the record to update
1638 * @enable: set to 1 if the record is tracing, zero to force disable
1639 *
1640 * The records that represent all functions that can be traced need
1641 * to be updated when tracing has been enabled.
1642 */
1643int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1644{
1645 return ftrace_check_record(rec, enable, 1);
1646}
1647
1648/**
1649 * ftrace_test_record, check if the record has been enabled or not
1650 * @rec: the record to test
1651 * @enable: set to 1 to check if enabled, 0 if it is disabled
1652 *
1653 * The arch code may need to test if a record is already set to
1654 * tracing to determine how to modify the function code that it
1655 * represents.
1656 */
1657int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1658{
1659 return ftrace_check_record(rec, enable, 0);
1660}
1661
1662static int
1663__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1664{
1665 unsigned long ftrace_addr;
1666 int ret;
1667
1668 ftrace_addr = (unsigned long)FTRACE_ADDR;
1669
1670 ret = ftrace_update_record(rec, enable);
1671
1672 switch (ret) {
1673 case FTRACE_UPDATE_IGNORE:
1674 return 0;
1675
1676 case FTRACE_UPDATE_MAKE_CALL:
1677 return ftrace_make_call(rec, ftrace_addr);
1678
1679 case FTRACE_UPDATE_MAKE_NOP:
1680 return ftrace_make_nop(NULL, rec, ftrace_addr);
1681 }
1682
1683 return -1; /* unknow ftrace bug */
1684}
1685
1686void __weak ftrace_replace_code(int enable)
1687{
1688 struct dyn_ftrace *rec;
1689 struct ftrace_page *pg;
1690 int failed;
1691
1692 if (unlikely(ftrace_disabled))
1693 return;
1694
1695 do_for_each_ftrace_rec(pg, rec) {
1696 failed = __ftrace_replace_code(rec, enable);
1697 if (failed) {
1698 ftrace_bug(failed, rec->ip);
1699 /* Stop processing */
1700 return;
1701 }
1702 } while_for_each_ftrace_rec();
1703}
1704
1705struct ftrace_rec_iter {
1706 struct ftrace_page *pg;
1707 int index;
1708};
1709
1710/**
1711 * ftrace_rec_iter_start, start up iterating over traced functions
1712 *
1713 * Returns an iterator handle that is used to iterate over all
1714 * the records that represent address locations where functions
1715 * are traced.
1716 *
1717 * May return NULL if no records are available.
1718 */
1719struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1720{
1721 /*
1722 * We only use a single iterator.
1723 * Protected by the ftrace_lock mutex.
1724 */
1725 static struct ftrace_rec_iter ftrace_rec_iter;
1726 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1727
1728 iter->pg = ftrace_pages_start;
1729 iter->index = 0;
1730
1731 /* Could have empty pages */
1732 while (iter->pg && !iter->pg->index)
1733 iter->pg = iter->pg->next;
1734
1735 if (!iter->pg)
1736 return NULL;
1737
1738 return iter;
1739}
1740
1741/**
1742 * ftrace_rec_iter_next, get the next record to process.
1743 * @iter: The handle to the iterator.
1744 *
1745 * Returns the next iterator after the given iterator @iter.
1746 */
1747struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1748{
1749 iter->index++;
1750
1751 if (iter->index >= iter->pg->index) {
1752 iter->pg = iter->pg->next;
1753 iter->index = 0;
1754
1755 /* Could have empty pages */
1756 while (iter->pg && !iter->pg->index)
1757 iter->pg = iter->pg->next;
1758 }
1759
1760 if (!iter->pg)
1761 return NULL;
1762
1763 return iter;
1764}
1765
1766/**
1767 * ftrace_rec_iter_record, get the record at the iterator location
1768 * @iter: The current iterator location
1769 *
1770 * Returns the record that the current @iter is at.
1771 */
1772struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1773{
1774 return &iter->pg->records[iter->index];
1775}
1776
1777static int
1778ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1779{
1780 unsigned long ip;
1781 int ret;
1782
1783 ip = rec->ip;
1784
1785 if (unlikely(ftrace_disabled))
1786 return 0;
1787
1788 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1789 if (ret) {
1790 ftrace_bug(ret, ip);
1791 return 0;
1792 }
1793 return 1;
1794}
1795
1796/*
1797 * archs can override this function if they must do something
1798 * before the modifying code is performed.
1799 */
1800int __weak ftrace_arch_code_modify_prepare(void)
1801{
1802 return 0;
1803}
1804
1805/*
1806 * archs can override this function if they must do something
1807 * after the modifying code is performed.
1808 */
1809int __weak ftrace_arch_code_modify_post_process(void)
1810{
1811 return 0;
1812}
1813
1814void ftrace_modify_all_code(int command)
1815{
1816 if (command & FTRACE_UPDATE_CALLS)
1817 ftrace_replace_code(1);
1818 else if (command & FTRACE_DISABLE_CALLS)
1819 ftrace_replace_code(0);
1820
1821 if (command & FTRACE_UPDATE_TRACE_FUNC)
1822 ftrace_update_ftrace_func(ftrace_trace_function);
1823
1824 if (command & FTRACE_START_FUNC_RET)
1825 ftrace_enable_ftrace_graph_caller();
1826 else if (command & FTRACE_STOP_FUNC_RET)
1827 ftrace_disable_ftrace_graph_caller();
1828}
1829
1830static int __ftrace_modify_code(void *data)
1831{
1832 int *command = data;
1833
1834 ftrace_modify_all_code(*command);
1835
1836 return 0;
1837}
1838
1839/**
1840 * ftrace_run_stop_machine, go back to the stop machine method
1841 * @command: The command to tell ftrace what to do
1842 *
1843 * If an arch needs to fall back to the stop machine method, the
1844 * it can call this function.
1845 */
1846void ftrace_run_stop_machine(int command)
1847{
1848 stop_machine(__ftrace_modify_code, &command, NULL);
1849}
1850
1851/**
1852 * arch_ftrace_update_code, modify the code to trace or not trace
1853 * @command: The command that needs to be done
1854 *
1855 * Archs can override this function if it does not need to
1856 * run stop_machine() to modify code.
1857 */
1858void __weak arch_ftrace_update_code(int command)
1859{
1860 ftrace_run_stop_machine(command);
1861}
1862
1863static void ftrace_run_update_code(int command)
1864{
1865 int ret;
1866
1867 ret = ftrace_arch_code_modify_prepare();
1868 FTRACE_WARN_ON(ret);
1869 if (ret)
1870 return;
1871 /*
1872 * Do not call function tracer while we update the code.
1873 * We are in stop machine.
1874 */
1875 function_trace_stop++;
1876
1877 /*
1878 * By default we use stop_machine() to modify the code.
1879 * But archs can do what ever they want as long as it
1880 * is safe. The stop_machine() is the safest, but also
1881 * produces the most overhead.
1882 */
1883 arch_ftrace_update_code(command);
1884
1885#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1886 /*
1887 * For archs that call ftrace_test_stop_func(), we must
1888 * wait till after we update all the function callers
1889 * before we update the callback. This keeps different
1890 * ops that record different functions from corrupting
1891 * each other.
1892 */
1893 __ftrace_trace_function = __ftrace_trace_function_delay;
1894#endif
1895 function_trace_stop--;
1896
1897 ret = ftrace_arch_code_modify_post_process();
1898 FTRACE_WARN_ON(ret);
1899}
1900
1901static ftrace_func_t saved_ftrace_func;
1902static int ftrace_start_up;
1903static int global_start_up;
1904
1905static void ftrace_startup_enable(int command)
1906{
1907 if (saved_ftrace_func != ftrace_trace_function) {
1908 saved_ftrace_func = ftrace_trace_function;
1909 command |= FTRACE_UPDATE_TRACE_FUNC;
1910 }
1911
1912 if (!command || !ftrace_enabled)
1913 return;
1914
1915 ftrace_run_update_code(command);
1916}
1917
1918static int ftrace_startup(struct ftrace_ops *ops, int command)
1919{
1920 bool hash_enable = true;
1921
1922 if (unlikely(ftrace_disabled))
1923 return -ENODEV;
1924
1925 ftrace_start_up++;
1926 command |= FTRACE_UPDATE_CALLS;
1927
1928 /* ops marked global share the filter hashes */
1929 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1930 ops = &global_ops;
1931 /* Don't update hash if global is already set */
1932 if (global_start_up)
1933 hash_enable = false;
1934 global_start_up++;
1935 }
1936
1937 ops->flags |= FTRACE_OPS_FL_ENABLED;
1938 if (hash_enable)
1939 ftrace_hash_rec_enable(ops, 1);
1940
1941 ftrace_startup_enable(command);
1942
1943 return 0;
1944}
1945
1946static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1947{
1948 bool hash_disable = true;
1949
1950 if (unlikely(ftrace_disabled))
1951 return;
1952
1953 ftrace_start_up--;
1954 /*
1955 * Just warn in case of unbalance, no need to kill ftrace, it's not
1956 * critical but the ftrace_call callers may be never nopped again after
1957 * further ftrace uses.
1958 */
1959 WARN_ON_ONCE(ftrace_start_up < 0);
1960
1961 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1962 ops = &global_ops;
1963 global_start_up--;
1964 WARN_ON_ONCE(global_start_up < 0);
1965 /* Don't update hash if global still has users */
1966 if (global_start_up) {
1967 WARN_ON_ONCE(!ftrace_start_up);
1968 hash_disable = false;
1969 }
1970 }
1971
1972 if (hash_disable)
1973 ftrace_hash_rec_disable(ops, 1);
1974
1975 if (ops != &global_ops || !global_start_up)
1976 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1977
1978 command |= FTRACE_UPDATE_CALLS;
1979
1980 if (saved_ftrace_func != ftrace_trace_function) {
1981 saved_ftrace_func = ftrace_trace_function;
1982 command |= FTRACE_UPDATE_TRACE_FUNC;
1983 }
1984
1985 if (!command || !ftrace_enabled)
1986 return;
1987
1988 ftrace_run_update_code(command);
1989}
1990
1991static void ftrace_startup_sysctl(void)
1992{
1993 if (unlikely(ftrace_disabled))
1994 return;
1995
1996 /* Force update next time */
1997 saved_ftrace_func = NULL;
1998 /* ftrace_start_up is true if we want ftrace running */
1999 if (ftrace_start_up)
2000 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2001}
2002
2003static void ftrace_shutdown_sysctl(void)
2004{
2005 if (unlikely(ftrace_disabled))
2006 return;
2007
2008 /* ftrace_start_up is true if ftrace is running */
2009 if (ftrace_start_up)
2010 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2011}
2012
2013static cycle_t ftrace_update_time;
2014static unsigned long ftrace_update_cnt;
2015unsigned long ftrace_update_tot_cnt;
2016
2017static int ops_traces_mod(struct ftrace_ops *ops)
2018{
2019 struct ftrace_hash *hash;
2020
2021 hash = ops->filter_hash;
2022 return ftrace_hash_empty(hash);
2023}
2024
2025static int ftrace_update_code(struct module *mod)
2026{
2027 struct ftrace_page *pg;
2028 struct dyn_ftrace *p;
2029 cycle_t start, stop;
2030 unsigned long ref = 0;
2031 int i;
2032
2033 /*
2034 * When adding a module, we need to check if tracers are
2035 * currently enabled and if they are set to trace all functions.
2036 * If they are, we need to enable the module functions as well
2037 * as update the reference counts for those function records.
2038 */
2039 if (mod) {
2040 struct ftrace_ops *ops;
2041
2042 for (ops = ftrace_ops_list;
2043 ops != &ftrace_list_end; ops = ops->next) {
2044 if (ops->flags & FTRACE_OPS_FL_ENABLED &&
2045 ops_traces_mod(ops))
2046 ref++;
2047 }
2048 }
2049
2050 start = ftrace_now(raw_smp_processor_id());
2051 ftrace_update_cnt = 0;
2052
2053 for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2054
2055 for (i = 0; i < pg->index; i++) {
2056 /* If something went wrong, bail without enabling anything */
2057 if (unlikely(ftrace_disabled))
2058 return -1;
2059
2060 p = &pg->records[i];
2061 p->flags = ref;
2062
2063 /*
2064 * Do the initial record conversion from mcount jump
2065 * to the NOP instructions.
2066 */
2067 if (!ftrace_code_disable(mod, p))
2068 break;
2069
2070 ftrace_update_cnt++;
2071
2072 /*
2073 * If the tracing is enabled, go ahead and enable the record.
2074 *
2075 * The reason not to enable the record immediatelly is the
2076 * inherent check of ftrace_make_nop/ftrace_make_call for
2077 * correct previous instructions. Making first the NOP
2078 * conversion puts the module to the correct state, thus
2079 * passing the ftrace_make_call check.
2080 */
2081 if (ftrace_start_up && ref) {
2082 int failed = __ftrace_replace_code(p, 1);
2083 if (failed)
2084 ftrace_bug(failed, p->ip);
2085 }
2086 }
2087 }
2088
2089 ftrace_new_pgs = NULL;
2090
2091 stop = ftrace_now(raw_smp_processor_id());
2092 ftrace_update_time = stop - start;
2093 ftrace_update_tot_cnt += ftrace_update_cnt;
2094
2095 return 0;
2096}
2097
2098static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2099{
2100 int order;
2101 int cnt;
2102
2103 if (WARN_ON(!count))
2104 return -EINVAL;
2105
2106 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2107
2108 /*
2109 * We want to fill as much as possible. No more than a page
2110 * may be empty.
2111 */
2112 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2113 order--;
2114
2115 again:
2116 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2117
2118 if (!pg->records) {
2119 /* if we can't allocate this size, try something smaller */
2120 if (!order)
2121 return -ENOMEM;
2122 order >>= 1;
2123 goto again;
2124 }
2125
2126 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2127 pg->size = cnt;
2128
2129 if (cnt > count)
2130 cnt = count;
2131
2132 return cnt;
2133}
2134
2135static struct ftrace_page *
2136ftrace_allocate_pages(unsigned long num_to_init)
2137{
2138 struct ftrace_page *start_pg;
2139 struct ftrace_page *pg;
2140 int order;
2141 int cnt;
2142
2143 if (!num_to_init)
2144 return 0;
2145
2146 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2147 if (!pg)
2148 return NULL;
2149
2150 /*
2151 * Try to allocate as much as possible in one continues
2152 * location that fills in all of the space. We want to
2153 * waste as little space as possible.
2154 */
2155 for (;;) {
2156 cnt = ftrace_allocate_records(pg, num_to_init);
2157 if (cnt < 0)
2158 goto free_pages;
2159
2160 num_to_init -= cnt;
2161 if (!num_to_init)
2162 break;
2163
2164 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2165 if (!pg->next)
2166 goto free_pages;
2167
2168 pg = pg->next;
2169 }
2170
2171 return start_pg;
2172
2173 free_pages:
2174 while (start_pg) {
2175 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2176 free_pages((unsigned long)pg->records, order);
2177 start_pg = pg->next;
2178 kfree(pg);
2179 pg = start_pg;
2180 }
2181 pr_info("ftrace: FAILED to allocate memory for functions\n");
2182 return NULL;
2183}
2184
2185static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2186{
2187 int cnt;
2188
2189 if (!num_to_init) {
2190 pr_info("ftrace: No functions to be traced?\n");
2191 return -1;
2192 }
2193
2194 cnt = num_to_init / ENTRIES_PER_PAGE;
2195 pr_info("ftrace: allocating %ld entries in %d pages\n",
2196 num_to_init, cnt + 1);
2197
2198 return 0;
2199}
2200
2201#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2202
2203struct ftrace_iterator {
2204 loff_t pos;
2205 loff_t func_pos;
2206 struct ftrace_page *pg;
2207 struct dyn_ftrace *func;
2208 struct ftrace_func_probe *probe;
2209 struct trace_parser parser;
2210 struct ftrace_hash *hash;
2211 struct ftrace_ops *ops;
2212 int hidx;
2213 int idx;
2214 unsigned flags;
2215};
2216
2217static void *
2218t_hash_next(struct seq_file *m, loff_t *pos)
2219{
2220 struct ftrace_iterator *iter = m->private;
2221 struct hlist_node *hnd = NULL;
2222 struct hlist_head *hhd;
2223
2224 (*pos)++;
2225 iter->pos = *pos;
2226
2227 if (iter->probe)
2228 hnd = &iter->probe->node;
2229 retry:
2230 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2231 return NULL;
2232
2233 hhd = &ftrace_func_hash[iter->hidx];
2234
2235 if (hlist_empty(hhd)) {
2236 iter->hidx++;
2237 hnd = NULL;
2238 goto retry;
2239 }
2240
2241 if (!hnd)
2242 hnd = hhd->first;
2243 else {
2244 hnd = hnd->next;
2245 if (!hnd) {
2246 iter->hidx++;
2247 goto retry;
2248 }
2249 }
2250
2251 if (WARN_ON_ONCE(!hnd))
2252 return NULL;
2253
2254 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2255
2256 return iter;
2257}
2258
2259static void *t_hash_start(struct seq_file *m, loff_t *pos)
2260{
2261 struct ftrace_iterator *iter = m->private;
2262 void *p = NULL;
2263 loff_t l;
2264
2265 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2266 return NULL;
2267
2268 if (iter->func_pos > *pos)
2269 return NULL;
2270
2271 iter->hidx = 0;
2272 for (l = 0; l <= (*pos - iter->func_pos); ) {
2273 p = t_hash_next(m, &l);
2274 if (!p)
2275 break;
2276 }
2277 if (!p)
2278 return NULL;
2279
2280 /* Only set this if we have an item */
2281 iter->flags |= FTRACE_ITER_HASH;
2282
2283 return iter;
2284}
2285
2286static int
2287t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2288{
2289 struct ftrace_func_probe *rec;
2290
2291 rec = iter->probe;
2292 if (WARN_ON_ONCE(!rec))
2293 return -EIO;
2294
2295 if (rec->ops->print)
2296 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2297
2298 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2299
2300 if (rec->data)
2301 seq_printf(m, ":%p", rec->data);
2302 seq_putc(m, '\n');
2303
2304 return 0;
2305}
2306
2307static void *
2308t_next(struct seq_file *m, void *v, loff_t *pos)
2309{
2310 struct ftrace_iterator *iter = m->private;
2311 struct ftrace_ops *ops = iter->ops;
2312 struct dyn_ftrace *rec = NULL;
2313
2314 if (unlikely(ftrace_disabled))
2315 return NULL;
2316
2317 if (iter->flags & FTRACE_ITER_HASH)
2318 return t_hash_next(m, pos);
2319
2320 (*pos)++;
2321 iter->pos = iter->func_pos = *pos;
2322
2323 if (iter->flags & FTRACE_ITER_PRINTALL)
2324 return t_hash_start(m, pos);
2325
2326 retry:
2327 if (iter->idx >= iter->pg->index) {
2328 if (iter->pg->next) {
2329 iter->pg = iter->pg->next;
2330 iter->idx = 0;
2331 goto retry;
2332 }
2333 } else {
2334 rec = &iter->pg->records[iter->idx++];
2335 if (((iter->flags & FTRACE_ITER_FILTER) &&
2336 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2337
2338 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2339 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2340
2341 ((iter->flags & FTRACE_ITER_ENABLED) &&
2342 !(rec->flags & ~FTRACE_FL_MASK))) {
2343
2344 rec = NULL;
2345 goto retry;
2346 }
2347 }
2348
2349 if (!rec)
2350 return t_hash_start(m, pos);
2351
2352 iter->func = rec;
2353
2354 return iter;
2355}
2356
2357static void reset_iter_read(struct ftrace_iterator *iter)
2358{
2359 iter->pos = 0;
2360 iter->func_pos = 0;
2361 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2362}
2363
2364static void *t_start(struct seq_file *m, loff_t *pos)
2365{
2366 struct ftrace_iterator *iter = m->private;
2367 struct ftrace_ops *ops = iter->ops;
2368 void *p = NULL;
2369 loff_t l;
2370
2371 mutex_lock(&ftrace_lock);
2372
2373 if (unlikely(ftrace_disabled))
2374 return NULL;
2375
2376 /*
2377 * If an lseek was done, then reset and start from beginning.
2378 */
2379 if (*pos < iter->pos)
2380 reset_iter_read(iter);
2381
2382 /*
2383 * For set_ftrace_filter reading, if we have the filter
2384 * off, we can short cut and just print out that all
2385 * functions are enabled.
2386 */
2387 if (iter->flags & FTRACE_ITER_FILTER &&
2388 ftrace_hash_empty(ops->filter_hash)) {
2389 if (*pos > 0)
2390 return t_hash_start(m, pos);
2391 iter->flags |= FTRACE_ITER_PRINTALL;
2392 /* reset in case of seek/pread */
2393 iter->flags &= ~FTRACE_ITER_HASH;
2394 return iter;
2395 }
2396
2397 if (iter->flags & FTRACE_ITER_HASH)
2398 return t_hash_start(m, pos);
2399
2400 /*
2401 * Unfortunately, we need to restart at ftrace_pages_start
2402 * every time we let go of the ftrace_mutex. This is because
2403 * those pointers can change without the lock.
2404 */
2405 iter->pg = ftrace_pages_start;
2406 iter->idx = 0;
2407 for (l = 0; l <= *pos; ) {
2408 p = t_next(m, p, &l);
2409 if (!p)
2410 break;
2411 }
2412
2413 if (!p)
2414 return t_hash_start(m, pos);
2415
2416 return iter;
2417}
2418
2419static void t_stop(struct seq_file *m, void *p)
2420{
2421 mutex_unlock(&ftrace_lock);
2422}
2423
2424static int t_show(struct seq_file *m, void *v)
2425{
2426 struct ftrace_iterator *iter = m->private;
2427 struct dyn_ftrace *rec;
2428
2429 if (iter->flags & FTRACE_ITER_HASH)
2430 return t_hash_show(m, iter);
2431
2432 if (iter->flags & FTRACE_ITER_PRINTALL) {
2433 seq_printf(m, "#### all functions enabled ####\n");
2434 return 0;
2435 }
2436
2437 rec = iter->func;
2438
2439 if (!rec)
2440 return 0;
2441
2442 seq_printf(m, "%ps", (void *)rec->ip);
2443 if (iter->flags & FTRACE_ITER_ENABLED)
2444 seq_printf(m, " (%ld)",
2445 rec->flags & ~FTRACE_FL_MASK);
2446 seq_printf(m, "\n");
2447
2448 return 0;
2449}
2450
2451static const struct seq_operations show_ftrace_seq_ops = {
2452 .start = t_start,
2453 .next = t_next,
2454 .stop = t_stop,
2455 .show = t_show,
2456};
2457
2458static int
2459ftrace_avail_open(struct inode *inode, struct file *file)
2460{
2461 struct ftrace_iterator *iter;
2462
2463 if (unlikely(ftrace_disabled))
2464 return -ENODEV;
2465
2466 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2467 if (iter) {
2468 iter->pg = ftrace_pages_start;
2469 iter->ops = &global_ops;
2470 }
2471
2472 return iter ? 0 : -ENOMEM;
2473}
2474
2475static int
2476ftrace_enabled_open(struct inode *inode, struct file *file)
2477{
2478 struct ftrace_iterator *iter;
2479
2480 if (unlikely(ftrace_disabled))
2481 return -ENODEV;
2482
2483 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2484 if (iter) {
2485 iter->pg = ftrace_pages_start;
2486 iter->flags = FTRACE_ITER_ENABLED;
2487 iter->ops = &global_ops;
2488 }
2489
2490 return iter ? 0 : -ENOMEM;
2491}
2492
2493static void ftrace_filter_reset(struct ftrace_hash *hash)
2494{
2495 mutex_lock(&ftrace_lock);
2496 ftrace_hash_clear(hash);
2497 mutex_unlock(&ftrace_lock);
2498}
2499
2500/**
2501 * ftrace_regex_open - initialize function tracer filter files
2502 * @ops: The ftrace_ops that hold the hash filters
2503 * @flag: The type of filter to process
2504 * @inode: The inode, usually passed in to your open routine
2505 * @file: The file, usually passed in to your open routine
2506 *
2507 * ftrace_regex_open() initializes the filter files for the
2508 * @ops. Depending on @flag it may process the filter hash or
2509 * the notrace hash of @ops. With this called from the open
2510 * routine, you can use ftrace_filter_write() for the write
2511 * routine if @flag has FTRACE_ITER_FILTER set, or
2512 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2513 * ftrace_regex_lseek() should be used as the lseek routine, and
2514 * release must call ftrace_regex_release().
2515 */
2516int
2517ftrace_regex_open(struct ftrace_ops *ops, int flag,
2518 struct inode *inode, struct file *file)
2519{
2520 struct ftrace_iterator *iter;
2521 struct ftrace_hash *hash;
2522 int ret = 0;
2523
2524 if (unlikely(ftrace_disabled))
2525 return -ENODEV;
2526
2527 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2528 if (!iter)
2529 return -ENOMEM;
2530
2531 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2532 kfree(iter);
2533 return -ENOMEM;
2534 }
2535
2536 if (flag & FTRACE_ITER_NOTRACE)
2537 hash = ops->notrace_hash;
2538 else
2539 hash = ops->filter_hash;
2540
2541 iter->ops = ops;
2542 iter->flags = flag;
2543
2544 if (file->f_mode & FMODE_WRITE) {
2545 mutex_lock(&ftrace_lock);
2546 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2547 mutex_unlock(&ftrace_lock);
2548
2549 if (!iter->hash) {
2550 trace_parser_put(&iter->parser);
2551 kfree(iter);
2552 return -ENOMEM;
2553 }
2554 }
2555
2556 mutex_lock(&ftrace_regex_lock);
2557
2558 if ((file->f_mode & FMODE_WRITE) &&
2559 (file->f_flags & O_TRUNC))
2560 ftrace_filter_reset(iter->hash);
2561
2562 if (file->f_mode & FMODE_READ) {
2563 iter->pg = ftrace_pages_start;
2564
2565 ret = seq_open(file, &show_ftrace_seq_ops);
2566 if (!ret) {
2567 struct seq_file *m = file->private_data;
2568 m->private = iter;
2569 } else {
2570 /* Failed */
2571 free_ftrace_hash(iter->hash);
2572 trace_parser_put(&iter->parser);
2573 kfree(iter);
2574 }
2575 } else
2576 file->private_data = iter;
2577 mutex_unlock(&ftrace_regex_lock);
2578
2579 return ret;
2580}
2581
2582static int
2583ftrace_filter_open(struct inode *inode, struct file *file)
2584{
2585 return ftrace_regex_open(&global_ops,
2586 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2587 inode, file);
2588}
2589
2590static int
2591ftrace_notrace_open(struct inode *inode, struct file *file)
2592{
2593 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2594 inode, file);
2595}
2596
2597loff_t
2598ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2599{
2600 loff_t ret;
2601
2602 if (file->f_mode & FMODE_READ)
2603 ret = seq_lseek(file, offset, origin);
2604 else
2605 file->f_pos = ret = 1;
2606
2607 return ret;
2608}
2609
2610static int ftrace_match(char *str, char *regex, int len, int type)
2611{
2612 int matched = 0;
2613 int slen;
2614
2615 switch (type) {
2616 case MATCH_FULL:
2617 if (strcmp(str, regex) == 0)
2618 matched = 1;
2619 break;
2620 case MATCH_FRONT_ONLY:
2621 if (strncmp(str, regex, len) == 0)
2622 matched = 1;
2623 break;
2624 case MATCH_MIDDLE_ONLY:
2625 if (strstr(str, regex))
2626 matched = 1;
2627 break;
2628 case MATCH_END_ONLY:
2629 slen = strlen(str);
2630 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2631 matched = 1;
2632 break;
2633 }
2634
2635 return matched;
2636}
2637
2638static int
2639enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2640{
2641 struct ftrace_func_entry *entry;
2642 int ret = 0;
2643
2644 entry = ftrace_lookup_ip(hash, rec->ip);
2645 if (not) {
2646 /* Do nothing if it doesn't exist */
2647 if (!entry)
2648 return 0;
2649
2650 free_hash_entry(hash, entry);
2651 } else {
2652 /* Do nothing if it exists */
2653 if (entry)
2654 return 0;
2655
2656 ret = add_hash_entry(hash, rec->ip);
2657 }
2658 return ret;
2659}
2660
2661static int
2662ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2663 char *regex, int len, int type)
2664{
2665 char str[KSYM_SYMBOL_LEN];
2666 char *modname;
2667
2668 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2669
2670 if (mod) {
2671 /* module lookup requires matching the module */
2672 if (!modname || strcmp(modname, mod))
2673 return 0;
2674
2675 /* blank search means to match all funcs in the mod */
2676 if (!len)
2677 return 1;
2678 }
2679
2680 return ftrace_match(str, regex, len, type);
2681}
2682
2683static int
2684match_records(struct ftrace_hash *hash, char *buff,
2685 int len, char *mod, int not)
2686{
2687 unsigned search_len = 0;
2688 struct ftrace_page *pg;
2689 struct dyn_ftrace *rec;
2690 int type = MATCH_FULL;
2691 char *search = buff;
2692 int found = 0;
2693 int ret;
2694
2695 if (len) {
2696 type = filter_parse_regex(buff, len, &search, ¬);
2697 search_len = strlen(search);
2698 }
2699
2700 mutex_lock(&ftrace_lock);
2701
2702 if (unlikely(ftrace_disabled))
2703 goto out_unlock;
2704
2705 do_for_each_ftrace_rec(pg, rec) {
2706 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2707 ret = enter_record(hash, rec, not);
2708 if (ret < 0) {
2709 found = ret;
2710 goto out_unlock;
2711 }
2712 found = 1;
2713 }
2714 } while_for_each_ftrace_rec();
2715 out_unlock:
2716 mutex_unlock(&ftrace_lock);
2717
2718 return found;
2719}
2720
2721static int
2722ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2723{
2724 return match_records(hash, buff, len, NULL, 0);
2725}
2726
2727static int
2728ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2729{
2730 int not = 0;
2731
2732 /* blank or '*' mean the same */
2733 if (strcmp(buff, "*") == 0)
2734 buff[0] = 0;
2735
2736 /* handle the case of 'dont filter this module' */
2737 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2738 buff[0] = 0;
2739 not = 1;
2740 }
2741
2742 return match_records(hash, buff, strlen(buff), mod, not);
2743}
2744
2745/*
2746 * We register the module command as a template to show others how
2747 * to register the a command as well.
2748 */
2749
2750static int
2751ftrace_mod_callback(struct ftrace_hash *hash,
2752 char *func, char *cmd, char *param, int enable)
2753{
2754 char *mod;
2755 int ret = -EINVAL;
2756
2757 /*
2758 * cmd == 'mod' because we only registered this func
2759 * for the 'mod' ftrace_func_command.
2760 * But if you register one func with multiple commands,
2761 * you can tell which command was used by the cmd
2762 * parameter.
2763 */
2764
2765 /* we must have a module name */
2766 if (!param)
2767 return ret;
2768
2769 mod = strsep(¶m, ":");
2770 if (!strlen(mod))
2771 return ret;
2772
2773 ret = ftrace_match_module_records(hash, func, mod);
2774 if (!ret)
2775 ret = -EINVAL;
2776 if (ret < 0)
2777 return ret;
2778
2779 return 0;
2780}
2781
2782static struct ftrace_func_command ftrace_mod_cmd = {
2783 .name = "mod",
2784 .func = ftrace_mod_callback,
2785};
2786
2787static int __init ftrace_mod_cmd_init(void)
2788{
2789 return register_ftrace_command(&ftrace_mod_cmd);
2790}
2791device_initcall(ftrace_mod_cmd_init);
2792
2793static void
2794function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2795{
2796 struct ftrace_func_probe *entry;
2797 struct hlist_head *hhd;
2798 struct hlist_node *n;
2799 unsigned long key;
2800
2801 key = hash_long(ip, FTRACE_HASH_BITS);
2802
2803 hhd = &ftrace_func_hash[key];
2804
2805 if (hlist_empty(hhd))
2806 return;
2807
2808 /*
2809 * Disable preemption for these calls to prevent a RCU grace
2810 * period. This syncs the hash iteration and freeing of items
2811 * on the hash. rcu_read_lock is too dangerous here.
2812 */
2813 preempt_disable_notrace();
2814 hlist_for_each_entry_rcu(entry, n, hhd, node) {
2815 if (entry->ip == ip)
2816 entry->ops->func(ip, parent_ip, &entry->data);
2817 }
2818 preempt_enable_notrace();
2819}
2820
2821static struct ftrace_ops trace_probe_ops __read_mostly =
2822{
2823 .func = function_trace_probe_call,
2824};
2825
2826static int ftrace_probe_registered;
2827
2828static void __enable_ftrace_function_probe(void)
2829{
2830 int ret;
2831 int i;
2832
2833 if (ftrace_probe_registered)
2834 return;
2835
2836 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2837 struct hlist_head *hhd = &ftrace_func_hash[i];
2838 if (hhd->first)
2839 break;
2840 }
2841 /* Nothing registered? */
2842 if (i == FTRACE_FUNC_HASHSIZE)
2843 return;
2844
2845 ret = __register_ftrace_function(&trace_probe_ops);
2846 if (!ret)
2847 ret = ftrace_startup(&trace_probe_ops, 0);
2848
2849 ftrace_probe_registered = 1;
2850}
2851
2852static void __disable_ftrace_function_probe(void)
2853{
2854 int ret;
2855 int i;
2856
2857 if (!ftrace_probe_registered)
2858 return;
2859
2860 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2861 struct hlist_head *hhd = &ftrace_func_hash[i];
2862 if (hhd->first)
2863 return;
2864 }
2865
2866 /* no more funcs left */
2867 ret = __unregister_ftrace_function(&trace_probe_ops);
2868 if (!ret)
2869 ftrace_shutdown(&trace_probe_ops, 0);
2870
2871 ftrace_probe_registered = 0;
2872}
2873
2874
2875static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2876{
2877 struct ftrace_func_probe *entry =
2878 container_of(rhp, struct ftrace_func_probe, rcu);
2879
2880 if (entry->ops->free)
2881 entry->ops->free(&entry->data);
2882 kfree(entry);
2883}
2884
2885
2886int
2887register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2888 void *data)
2889{
2890 struct ftrace_func_probe *entry;
2891 struct ftrace_page *pg;
2892 struct dyn_ftrace *rec;
2893 int type, len, not;
2894 unsigned long key;
2895 int count = 0;
2896 char *search;
2897
2898 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2899 len = strlen(search);
2900
2901 /* we do not support '!' for function probes */
2902 if (WARN_ON(not))
2903 return -EINVAL;
2904
2905 mutex_lock(&ftrace_lock);
2906
2907 if (unlikely(ftrace_disabled))
2908 goto out_unlock;
2909
2910 do_for_each_ftrace_rec(pg, rec) {
2911
2912 if (!ftrace_match_record(rec, NULL, search, len, type))
2913 continue;
2914
2915 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2916 if (!entry) {
2917 /* If we did not process any, then return error */
2918 if (!count)
2919 count = -ENOMEM;
2920 goto out_unlock;
2921 }
2922
2923 count++;
2924
2925 entry->data = data;
2926
2927 /*
2928 * The caller might want to do something special
2929 * for each function we find. We call the callback
2930 * to give the caller an opportunity to do so.
2931 */
2932 if (ops->callback) {
2933 if (ops->callback(rec->ip, &entry->data) < 0) {
2934 /* caller does not like this func */
2935 kfree(entry);
2936 continue;
2937 }
2938 }
2939
2940 entry->ops = ops;
2941 entry->ip = rec->ip;
2942
2943 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2944 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2945
2946 } while_for_each_ftrace_rec();
2947 __enable_ftrace_function_probe();
2948
2949 out_unlock:
2950 mutex_unlock(&ftrace_lock);
2951
2952 return count;
2953}
2954
2955enum {
2956 PROBE_TEST_FUNC = 1,
2957 PROBE_TEST_DATA = 2
2958};
2959
2960static void
2961__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2962 void *data, int flags)
2963{
2964 struct ftrace_func_probe *entry;
2965 struct hlist_node *n, *tmp;
2966 char str[KSYM_SYMBOL_LEN];
2967 int type = MATCH_FULL;
2968 int i, len = 0;
2969 char *search;
2970
2971 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2972 glob = NULL;
2973 else if (glob) {
2974 int not;
2975
2976 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2977 len = strlen(search);
2978
2979 /* we do not support '!' for function probes */
2980 if (WARN_ON(not))
2981 return;
2982 }
2983
2984 mutex_lock(&ftrace_lock);
2985 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2986 struct hlist_head *hhd = &ftrace_func_hash[i];
2987
2988 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2989
2990 /* break up if statements for readability */
2991 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2992 continue;
2993
2994 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2995 continue;
2996
2997 /* do this last, since it is the most expensive */
2998 if (glob) {
2999 kallsyms_lookup(entry->ip, NULL, NULL,
3000 NULL, str);
3001 if (!ftrace_match(str, glob, len, type))
3002 continue;
3003 }
3004
3005 hlist_del(&entry->node);
3006 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
3007 }
3008 }
3009 __disable_ftrace_function_probe();
3010 mutex_unlock(&ftrace_lock);
3011}
3012
3013void
3014unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3015 void *data)
3016{
3017 __unregister_ftrace_function_probe(glob, ops, data,
3018 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3019}
3020
3021void
3022unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3023{
3024 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3025}
3026
3027void unregister_ftrace_function_probe_all(char *glob)
3028{
3029 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3030}
3031
3032static LIST_HEAD(ftrace_commands);
3033static DEFINE_MUTEX(ftrace_cmd_mutex);
3034
3035int register_ftrace_command(struct ftrace_func_command *cmd)
3036{
3037 struct ftrace_func_command *p;
3038 int ret = 0;
3039
3040 mutex_lock(&ftrace_cmd_mutex);
3041 list_for_each_entry(p, &ftrace_commands, list) {
3042 if (strcmp(cmd->name, p->name) == 0) {
3043 ret = -EBUSY;
3044 goto out_unlock;
3045 }
3046 }
3047 list_add(&cmd->list, &ftrace_commands);
3048 out_unlock:
3049 mutex_unlock(&ftrace_cmd_mutex);
3050
3051 return ret;
3052}
3053
3054int unregister_ftrace_command(struct ftrace_func_command *cmd)
3055{
3056 struct ftrace_func_command *p, *n;
3057 int ret = -ENODEV;
3058
3059 mutex_lock(&ftrace_cmd_mutex);
3060 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3061 if (strcmp(cmd->name, p->name) == 0) {
3062 ret = 0;
3063 list_del_init(&p->list);
3064 goto out_unlock;
3065 }
3066 }
3067 out_unlock:
3068 mutex_unlock(&ftrace_cmd_mutex);
3069
3070 return ret;
3071}
3072
3073static int ftrace_process_regex(struct ftrace_hash *hash,
3074 char *buff, int len, int enable)
3075{
3076 char *func, *command, *next = buff;
3077 struct ftrace_func_command *p;
3078 int ret = -EINVAL;
3079
3080 func = strsep(&next, ":");
3081
3082 if (!next) {
3083 ret = ftrace_match_records(hash, func, len);
3084 if (!ret)
3085 ret = -EINVAL;
3086 if (ret < 0)
3087 return ret;
3088 return 0;
3089 }
3090
3091 /* command found */
3092
3093 command = strsep(&next, ":");
3094
3095 mutex_lock(&ftrace_cmd_mutex);
3096 list_for_each_entry(p, &ftrace_commands, list) {
3097 if (strcmp(p->name, command) == 0) {
3098 ret = p->func(hash, func, command, next, enable);
3099 goto out_unlock;
3100 }
3101 }
3102 out_unlock:
3103 mutex_unlock(&ftrace_cmd_mutex);
3104
3105 return ret;
3106}
3107
3108static ssize_t
3109ftrace_regex_write(struct file *file, const char __user *ubuf,
3110 size_t cnt, loff_t *ppos, int enable)
3111{
3112 struct ftrace_iterator *iter;
3113 struct trace_parser *parser;
3114 ssize_t ret, read;
3115
3116 if (!cnt)
3117 return 0;
3118
3119 mutex_lock(&ftrace_regex_lock);
3120
3121 ret = -ENODEV;
3122 if (unlikely(ftrace_disabled))
3123 goto out_unlock;
3124
3125 if (file->f_mode & FMODE_READ) {
3126 struct seq_file *m = file->private_data;
3127 iter = m->private;
3128 } else
3129 iter = file->private_data;
3130
3131 parser = &iter->parser;
3132 read = trace_get_user(parser, ubuf, cnt, ppos);
3133
3134 if (read >= 0 && trace_parser_loaded(parser) &&
3135 !trace_parser_cont(parser)) {
3136 ret = ftrace_process_regex(iter->hash, parser->buffer,
3137 parser->idx, enable);
3138 trace_parser_clear(parser);
3139 if (ret)
3140 goto out_unlock;
3141 }
3142
3143 ret = read;
3144out_unlock:
3145 mutex_unlock(&ftrace_regex_lock);
3146
3147 return ret;
3148}
3149
3150ssize_t
3151ftrace_filter_write(struct file *file, const char __user *ubuf,
3152 size_t cnt, loff_t *ppos)
3153{
3154 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3155}
3156
3157ssize_t
3158ftrace_notrace_write(struct file *file, const char __user *ubuf,
3159 size_t cnt, loff_t *ppos)
3160{
3161 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3162}
3163
3164static int
3165ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3166 int reset, int enable)
3167{
3168 struct ftrace_hash **orig_hash;
3169 struct ftrace_hash *hash;
3170 int ret;
3171
3172 /* All global ops uses the global ops filters */
3173 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3174 ops = &global_ops;
3175
3176 if (unlikely(ftrace_disabled))
3177 return -ENODEV;
3178
3179 if (enable)
3180 orig_hash = &ops->filter_hash;
3181 else
3182 orig_hash = &ops->notrace_hash;
3183
3184 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3185 if (!hash)
3186 return -ENOMEM;
3187
3188 mutex_lock(&ftrace_regex_lock);
3189 if (reset)
3190 ftrace_filter_reset(hash);
3191 if (buf && !ftrace_match_records(hash, buf, len)) {
3192 ret = -EINVAL;
3193 goto out_regex_unlock;
3194 }
3195
3196 mutex_lock(&ftrace_lock);
3197 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3198 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3199 && ftrace_enabled)
3200 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3201
3202 mutex_unlock(&ftrace_lock);
3203
3204 out_regex_unlock:
3205 mutex_unlock(&ftrace_regex_lock);
3206
3207 free_ftrace_hash(hash);
3208 return ret;
3209}
3210
3211/**
3212 * ftrace_set_filter - set a function to filter on in ftrace
3213 * @ops - the ops to set the filter with
3214 * @buf - the string that holds the function filter text.
3215 * @len - the length of the string.
3216 * @reset - non zero to reset all filters before applying this filter.
3217 *
3218 * Filters denote which functions should be enabled when tracing is enabled.
3219 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3220 */
3221int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3222 int len, int reset)
3223{
3224 return ftrace_set_regex(ops, buf, len, reset, 1);
3225}
3226EXPORT_SYMBOL_GPL(ftrace_set_filter);
3227
3228/**
3229 * ftrace_set_notrace - set a function to not trace in ftrace
3230 * @ops - the ops to set the notrace filter with
3231 * @buf - the string that holds the function notrace text.
3232 * @len - the length of the string.
3233 * @reset - non zero to reset all filters before applying this filter.
3234 *
3235 * Notrace Filters denote which functions should not be enabled when tracing
3236 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3237 * for tracing.
3238 */
3239int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3240 int len, int reset)
3241{
3242 return ftrace_set_regex(ops, buf, len, reset, 0);
3243}
3244EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3245/**
3246 * ftrace_set_filter - set a function to filter on in ftrace
3247 * @ops - the ops to set the filter with
3248 * @buf - the string that holds the function filter text.
3249 * @len - the length of the string.
3250 * @reset - non zero to reset all filters before applying this filter.
3251 *
3252 * Filters denote which functions should be enabled when tracing is enabled.
3253 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3254 */
3255void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3256{
3257 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3258}
3259EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3260
3261/**
3262 * ftrace_set_notrace - set a function to not trace in ftrace
3263 * @ops - the ops to set the notrace filter with
3264 * @buf - the string that holds the function notrace text.
3265 * @len - the length of the string.
3266 * @reset - non zero to reset all filters before applying this filter.
3267 *
3268 * Notrace Filters denote which functions should not be enabled when tracing
3269 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3270 * for tracing.
3271 */
3272void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3273{
3274 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3275}
3276EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3277
3278/*
3279 * command line interface to allow users to set filters on boot up.
3280 */
3281#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3282static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3283static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3284
3285static int __init set_ftrace_notrace(char *str)
3286{
3287 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3288 return 1;
3289}
3290__setup("ftrace_notrace=", set_ftrace_notrace);
3291
3292static int __init set_ftrace_filter(char *str)
3293{
3294 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3295 return 1;
3296}
3297__setup("ftrace_filter=", set_ftrace_filter);
3298
3299#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3300static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3301static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3302
3303static int __init set_graph_function(char *str)
3304{
3305 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3306 return 1;
3307}
3308__setup("ftrace_graph_filter=", set_graph_function);
3309
3310static void __init set_ftrace_early_graph(char *buf)
3311{
3312 int ret;
3313 char *func;
3314
3315 while (buf) {
3316 func = strsep(&buf, ",");
3317 /* we allow only one expression at a time */
3318 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3319 func);
3320 if (ret)
3321 printk(KERN_DEBUG "ftrace: function %s not "
3322 "traceable\n", func);
3323 }
3324}
3325#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3326
3327void __init
3328ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3329{
3330 char *func;
3331
3332 while (buf) {
3333 func = strsep(&buf, ",");
3334 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3335 }
3336}
3337
3338static void __init set_ftrace_early_filters(void)
3339{
3340 if (ftrace_filter_buf[0])
3341 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3342 if (ftrace_notrace_buf[0])
3343 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3344#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3345 if (ftrace_graph_buf[0])
3346 set_ftrace_early_graph(ftrace_graph_buf);
3347#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3348}
3349
3350int ftrace_regex_release(struct inode *inode, struct file *file)
3351{
3352 struct seq_file *m = (struct seq_file *)file->private_data;
3353 struct ftrace_iterator *iter;
3354 struct ftrace_hash **orig_hash;
3355 struct trace_parser *parser;
3356 int filter_hash;
3357 int ret;
3358
3359 mutex_lock(&ftrace_regex_lock);
3360 if (file->f_mode & FMODE_READ) {
3361 iter = m->private;
3362
3363 seq_release(inode, file);
3364 } else
3365 iter = file->private_data;
3366
3367 parser = &iter->parser;
3368 if (trace_parser_loaded(parser)) {
3369 parser->buffer[parser->idx] = 0;
3370 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3371 }
3372
3373 trace_parser_put(parser);
3374
3375 if (file->f_mode & FMODE_WRITE) {
3376 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3377
3378 if (filter_hash)
3379 orig_hash = &iter->ops->filter_hash;
3380 else
3381 orig_hash = &iter->ops->notrace_hash;
3382
3383 mutex_lock(&ftrace_lock);
3384 ret = ftrace_hash_move(iter->ops, filter_hash,
3385 orig_hash, iter->hash);
3386 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3387 && ftrace_enabled)
3388 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3389
3390 mutex_unlock(&ftrace_lock);
3391 }
3392 free_ftrace_hash(iter->hash);
3393 kfree(iter);
3394
3395 mutex_unlock(&ftrace_regex_lock);
3396 return 0;
3397}
3398
3399static const struct file_operations ftrace_avail_fops = {
3400 .open = ftrace_avail_open,
3401 .read = seq_read,
3402 .llseek = seq_lseek,
3403 .release = seq_release_private,
3404};
3405
3406static const struct file_operations ftrace_enabled_fops = {
3407 .open = ftrace_enabled_open,
3408 .read = seq_read,
3409 .llseek = seq_lseek,
3410 .release = seq_release_private,
3411};
3412
3413static const struct file_operations ftrace_filter_fops = {
3414 .open = ftrace_filter_open,
3415 .read = seq_read,
3416 .write = ftrace_filter_write,
3417 .llseek = ftrace_regex_lseek,
3418 .release = ftrace_regex_release,
3419};
3420
3421static const struct file_operations ftrace_notrace_fops = {
3422 .open = ftrace_notrace_open,
3423 .read = seq_read,
3424 .write = ftrace_notrace_write,
3425 .llseek = ftrace_regex_lseek,
3426 .release = ftrace_regex_release,
3427};
3428
3429#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3430
3431static DEFINE_MUTEX(graph_lock);
3432
3433int ftrace_graph_count;
3434int ftrace_graph_filter_enabled;
3435unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3436
3437static void *
3438__g_next(struct seq_file *m, loff_t *pos)
3439{
3440 if (*pos >= ftrace_graph_count)
3441 return NULL;
3442 return &ftrace_graph_funcs[*pos];
3443}
3444
3445static void *
3446g_next(struct seq_file *m, void *v, loff_t *pos)
3447{
3448 (*pos)++;
3449 return __g_next(m, pos);
3450}
3451
3452static void *g_start(struct seq_file *m, loff_t *pos)
3453{
3454 mutex_lock(&graph_lock);
3455
3456 /* Nothing, tell g_show to print all functions are enabled */
3457 if (!ftrace_graph_filter_enabled && !*pos)
3458 return (void *)1;
3459
3460 return __g_next(m, pos);
3461}
3462
3463static void g_stop(struct seq_file *m, void *p)
3464{
3465 mutex_unlock(&graph_lock);
3466}
3467
3468static int g_show(struct seq_file *m, void *v)
3469{
3470 unsigned long *ptr = v;
3471
3472 if (!ptr)
3473 return 0;
3474
3475 if (ptr == (unsigned long *)1) {
3476 seq_printf(m, "#### all functions enabled ####\n");
3477 return 0;
3478 }
3479
3480 seq_printf(m, "%ps\n", (void *)*ptr);
3481
3482 return 0;
3483}
3484
3485static const struct seq_operations ftrace_graph_seq_ops = {
3486 .start = g_start,
3487 .next = g_next,
3488 .stop = g_stop,
3489 .show = g_show,
3490};
3491
3492static int
3493ftrace_graph_open(struct inode *inode, struct file *file)
3494{
3495 int ret = 0;
3496
3497 if (unlikely(ftrace_disabled))
3498 return -ENODEV;
3499
3500 mutex_lock(&graph_lock);
3501 if ((file->f_mode & FMODE_WRITE) &&
3502 (file->f_flags & O_TRUNC)) {
3503 ftrace_graph_filter_enabled = 0;
3504 ftrace_graph_count = 0;
3505 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3506 }
3507 mutex_unlock(&graph_lock);
3508
3509 if (file->f_mode & FMODE_READ)
3510 ret = seq_open(file, &ftrace_graph_seq_ops);
3511
3512 return ret;
3513}
3514
3515static int
3516ftrace_graph_release(struct inode *inode, struct file *file)
3517{
3518 if (file->f_mode & FMODE_READ)
3519 seq_release(inode, file);
3520 return 0;
3521}
3522
3523static int
3524ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3525{
3526 struct dyn_ftrace *rec;
3527 struct ftrace_page *pg;
3528 int search_len;
3529 int fail = 1;
3530 int type, not;
3531 char *search;
3532 bool exists;
3533 int i;
3534
3535 /* decode regex */
3536 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3537 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3538 return -EBUSY;
3539
3540 search_len = strlen(search);
3541
3542 mutex_lock(&ftrace_lock);
3543
3544 if (unlikely(ftrace_disabled)) {
3545 mutex_unlock(&ftrace_lock);
3546 return -ENODEV;
3547 }
3548
3549 do_for_each_ftrace_rec(pg, rec) {
3550
3551 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3552 /* if it is in the array */
3553 exists = false;
3554 for (i = 0; i < *idx; i++) {
3555 if (array[i] == rec->ip) {
3556 exists = true;
3557 break;
3558 }
3559 }
3560
3561 if (!not) {
3562 fail = 0;
3563 if (!exists) {
3564 array[(*idx)++] = rec->ip;
3565 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3566 goto out;
3567 }
3568 } else {
3569 if (exists) {
3570 array[i] = array[--(*idx)];
3571 array[*idx] = 0;
3572 fail = 0;
3573 }
3574 }
3575 }
3576 } while_for_each_ftrace_rec();
3577out:
3578 mutex_unlock(&ftrace_lock);
3579
3580 if (fail)
3581 return -EINVAL;
3582
3583 ftrace_graph_filter_enabled = 1;
3584 return 0;
3585}
3586
3587static ssize_t
3588ftrace_graph_write(struct file *file, const char __user *ubuf,
3589 size_t cnt, loff_t *ppos)
3590{
3591 struct trace_parser parser;
3592 ssize_t read, ret;
3593
3594 if (!cnt)
3595 return 0;
3596
3597 mutex_lock(&graph_lock);
3598
3599 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3600 ret = -ENOMEM;
3601 goto out_unlock;
3602 }
3603
3604 read = trace_get_user(&parser, ubuf, cnt, ppos);
3605
3606 if (read >= 0 && trace_parser_loaded((&parser))) {
3607 parser.buffer[parser.idx] = 0;
3608
3609 /* we allow only one expression at a time */
3610 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3611 parser.buffer);
3612 if (ret)
3613 goto out_free;
3614 }
3615
3616 ret = read;
3617
3618out_free:
3619 trace_parser_put(&parser);
3620out_unlock:
3621 mutex_unlock(&graph_lock);
3622
3623 return ret;
3624}
3625
3626static const struct file_operations ftrace_graph_fops = {
3627 .open = ftrace_graph_open,
3628 .read = seq_read,
3629 .write = ftrace_graph_write,
3630 .release = ftrace_graph_release,
3631 .llseek = seq_lseek,
3632};
3633#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3634
3635static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3636{
3637
3638 trace_create_file("available_filter_functions", 0444,
3639 d_tracer, NULL, &ftrace_avail_fops);
3640
3641 trace_create_file("enabled_functions", 0444,
3642 d_tracer, NULL, &ftrace_enabled_fops);
3643
3644 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3645 NULL, &ftrace_filter_fops);
3646
3647 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3648 NULL, &ftrace_notrace_fops);
3649
3650#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3651 trace_create_file("set_graph_function", 0444, d_tracer,
3652 NULL,
3653 &ftrace_graph_fops);
3654#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3655
3656 return 0;
3657}
3658
3659static int ftrace_cmp_ips(const void *a, const void *b)
3660{
3661 const unsigned long *ipa = a;
3662 const unsigned long *ipb = b;
3663
3664 if (*ipa > *ipb)
3665 return 1;
3666 if (*ipa < *ipb)
3667 return -1;
3668 return 0;
3669}
3670
3671static void ftrace_swap_ips(void *a, void *b, int size)
3672{
3673 unsigned long *ipa = a;
3674 unsigned long *ipb = b;
3675 unsigned long t;
3676
3677 t = *ipa;
3678 *ipa = *ipb;
3679 *ipb = t;
3680}
3681
3682static int ftrace_process_locs(struct module *mod,
3683 unsigned long *start,
3684 unsigned long *end)
3685{
3686 struct ftrace_page *start_pg;
3687 struct ftrace_page *pg;
3688 struct dyn_ftrace *rec;
3689 unsigned long count;
3690 unsigned long *p;
3691 unsigned long addr;
3692 unsigned long flags = 0; /* Shut up gcc */
3693 int ret = -ENOMEM;
3694
3695 count = end - start;
3696
3697 if (!count)
3698 return 0;
3699
3700 sort(start, count, sizeof(*start),
3701 ftrace_cmp_ips, ftrace_swap_ips);
3702
3703 start_pg = ftrace_allocate_pages(count);
3704 if (!start_pg)
3705 return -ENOMEM;
3706
3707 mutex_lock(&ftrace_lock);
3708
3709 /*
3710 * Core and each module needs their own pages, as
3711 * modules will free them when they are removed.
3712 * Force a new page to be allocated for modules.
3713 */
3714 if (!mod) {
3715 WARN_ON(ftrace_pages || ftrace_pages_start);
3716 /* First initialization */
3717 ftrace_pages = ftrace_pages_start = start_pg;
3718 } else {
3719 if (!ftrace_pages)
3720 goto out;
3721
3722 if (WARN_ON(ftrace_pages->next)) {
3723 /* Hmm, we have free pages? */
3724 while (ftrace_pages->next)
3725 ftrace_pages = ftrace_pages->next;
3726 }
3727
3728 ftrace_pages->next = start_pg;
3729 }
3730
3731 p = start;
3732 pg = start_pg;
3733 while (p < end) {
3734 addr = ftrace_call_adjust(*p++);
3735 /*
3736 * Some architecture linkers will pad between
3737 * the different mcount_loc sections of different
3738 * object files to satisfy alignments.
3739 * Skip any NULL pointers.
3740 */
3741 if (!addr)
3742 continue;
3743
3744 if (pg->index == pg->size) {
3745 /* We should have allocated enough */
3746 if (WARN_ON(!pg->next))
3747 break;
3748 pg = pg->next;
3749 }
3750
3751 rec = &pg->records[pg->index++];
3752 rec->ip = addr;
3753 }
3754
3755 /* We should have used all pages */
3756 WARN_ON(pg->next);
3757
3758 /* Assign the last page to ftrace_pages */
3759 ftrace_pages = pg;
3760
3761 /* These new locations need to be initialized */
3762 ftrace_new_pgs = start_pg;
3763
3764 /*
3765 * We only need to disable interrupts on start up
3766 * because we are modifying code that an interrupt
3767 * may execute, and the modification is not atomic.
3768 * But for modules, nothing runs the code we modify
3769 * until we are finished with it, and there's no
3770 * reason to cause large interrupt latencies while we do it.
3771 */
3772 if (!mod)
3773 local_irq_save(flags);
3774 ftrace_update_code(mod);
3775 if (!mod)
3776 local_irq_restore(flags);
3777 ret = 0;
3778 out:
3779 mutex_unlock(&ftrace_lock);
3780
3781 return ret;
3782}
3783
3784#ifdef CONFIG_MODULES
3785
3786#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
3787
3788void ftrace_release_mod(struct module *mod)
3789{
3790 struct dyn_ftrace *rec;
3791 struct ftrace_page **last_pg;
3792 struct ftrace_page *pg;
3793 int order;
3794
3795 mutex_lock(&ftrace_lock);
3796
3797 if (ftrace_disabled)
3798 goto out_unlock;
3799
3800 /*
3801 * Each module has its own ftrace_pages, remove
3802 * them from the list.
3803 */
3804 last_pg = &ftrace_pages_start;
3805 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
3806 rec = &pg->records[0];
3807 if (within_module_core(rec->ip, mod)) {
3808 /*
3809 * As core pages are first, the first
3810 * page should never be a module page.
3811 */
3812 if (WARN_ON(pg == ftrace_pages_start))
3813 goto out_unlock;
3814
3815 /* Check if we are deleting the last page */
3816 if (pg == ftrace_pages)
3817 ftrace_pages = next_to_ftrace_page(last_pg);
3818
3819 *last_pg = pg->next;
3820 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3821 free_pages((unsigned long)pg->records, order);
3822 kfree(pg);
3823 } else
3824 last_pg = &pg->next;
3825 }
3826 out_unlock:
3827 mutex_unlock(&ftrace_lock);
3828}
3829
3830static void ftrace_init_module(struct module *mod,
3831 unsigned long *start, unsigned long *end)
3832{
3833 if (ftrace_disabled || start == end)
3834 return;
3835 ftrace_process_locs(mod, start, end);
3836}
3837
3838static int ftrace_module_notify(struct notifier_block *self,
3839 unsigned long val, void *data)
3840{
3841 struct module *mod = data;
3842
3843 switch (val) {
3844 case MODULE_STATE_COMING:
3845 ftrace_init_module(mod, mod->ftrace_callsites,
3846 mod->ftrace_callsites +
3847 mod->num_ftrace_callsites);
3848 break;
3849 case MODULE_STATE_GOING:
3850 ftrace_release_mod(mod);
3851 break;
3852 }
3853
3854 return 0;
3855}
3856#else
3857static int ftrace_module_notify(struct notifier_block *self,
3858 unsigned long val, void *data)
3859{
3860 return 0;
3861}
3862#endif /* CONFIG_MODULES */
3863
3864struct notifier_block ftrace_module_nb = {
3865 .notifier_call = ftrace_module_notify,
3866 .priority = 0,
3867};
3868
3869extern unsigned long __start_mcount_loc[];
3870extern unsigned long __stop_mcount_loc[];
3871
3872void __init ftrace_init(void)
3873{
3874 unsigned long count, addr, flags;
3875 int ret;
3876
3877 /* Keep the ftrace pointer to the stub */
3878 addr = (unsigned long)ftrace_stub;
3879
3880 local_irq_save(flags);
3881 ftrace_dyn_arch_init(&addr);
3882 local_irq_restore(flags);
3883
3884 /* ftrace_dyn_arch_init places the return code in addr */
3885 if (addr)
3886 goto failed;
3887
3888 count = __stop_mcount_loc - __start_mcount_loc;
3889
3890 ret = ftrace_dyn_table_alloc(count);
3891 if (ret)
3892 goto failed;
3893
3894 last_ftrace_enabled = ftrace_enabled = 1;
3895
3896 ret = ftrace_process_locs(NULL,
3897 __start_mcount_loc,
3898 __stop_mcount_loc);
3899
3900 ret = register_module_notifier(&ftrace_module_nb);
3901 if (ret)
3902 pr_warning("Failed to register trace ftrace module notifier\n");
3903
3904 set_ftrace_early_filters();
3905
3906 return;
3907 failed:
3908 ftrace_disabled = 1;
3909}
3910
3911#else
3912
3913static struct ftrace_ops global_ops = {
3914 .func = ftrace_stub,
3915};
3916
3917static int __init ftrace_nodyn_init(void)
3918{
3919 ftrace_enabled = 1;
3920 return 0;
3921}
3922device_initcall(ftrace_nodyn_init);
3923
3924static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3925static inline void ftrace_startup_enable(int command) { }
3926/* Keep as macros so we do not need to define the commands */
3927# define ftrace_startup(ops, command) \
3928 ({ \
3929 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3930 0; \
3931 })
3932# define ftrace_shutdown(ops, command) do { } while (0)
3933# define ftrace_startup_sysctl() do { } while (0)
3934# define ftrace_shutdown_sysctl() do { } while (0)
3935
3936static inline int
3937ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3938{
3939 return 1;
3940}
3941
3942#endif /* CONFIG_DYNAMIC_FTRACE */
3943
3944static void
3945ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip)
3946{
3947 struct ftrace_ops *op;
3948
3949 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
3950 return;
3951
3952 /*
3953 * Some of the ops may be dynamically allocated,
3954 * they must be freed after a synchronize_sched().
3955 */
3956 preempt_disable_notrace();
3957 trace_recursion_set(TRACE_CONTROL_BIT);
3958 op = rcu_dereference_raw(ftrace_control_list);
3959 while (op != &ftrace_list_end) {
3960 if (!ftrace_function_local_disabled(op) &&
3961 ftrace_ops_test(op, ip))
3962 op->func(ip, parent_ip);
3963
3964 op = rcu_dereference_raw(op->next);
3965 };
3966 trace_recursion_clear(TRACE_CONTROL_BIT);
3967 preempt_enable_notrace();
3968}
3969
3970static struct ftrace_ops control_ops = {
3971 .func = ftrace_ops_control_func,
3972};
3973
3974static void
3975ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3976{
3977 struct ftrace_ops *op;
3978
3979 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3980 return;
3981
3982 trace_recursion_set(TRACE_INTERNAL_BIT);
3983 /*
3984 * Some of the ops may be dynamically allocated,
3985 * they must be freed after a synchronize_sched().
3986 */
3987 preempt_disable_notrace();
3988 op = rcu_dereference_raw(ftrace_ops_list);
3989 while (op != &ftrace_list_end) {
3990 if (ftrace_ops_test(op, ip))
3991 op->func(ip, parent_ip);
3992 op = rcu_dereference_raw(op->next);
3993 };
3994 preempt_enable_notrace();
3995 trace_recursion_clear(TRACE_INTERNAL_BIT);
3996}
3997
3998static void clear_ftrace_swapper(void)
3999{
4000 struct task_struct *p;
4001 int cpu;
4002
4003 get_online_cpus();
4004 for_each_online_cpu(cpu) {
4005 p = idle_task(cpu);
4006 clear_tsk_trace_trace(p);
4007 }
4008 put_online_cpus();
4009}
4010
4011static void set_ftrace_swapper(void)
4012{
4013 struct task_struct *p;
4014 int cpu;
4015
4016 get_online_cpus();
4017 for_each_online_cpu(cpu) {
4018 p = idle_task(cpu);
4019 set_tsk_trace_trace(p);
4020 }
4021 put_online_cpus();
4022}
4023
4024static void clear_ftrace_pid(struct pid *pid)
4025{
4026 struct task_struct *p;
4027
4028 rcu_read_lock();
4029 do_each_pid_task(pid, PIDTYPE_PID, p) {
4030 clear_tsk_trace_trace(p);
4031 } while_each_pid_task(pid, PIDTYPE_PID, p);
4032 rcu_read_unlock();
4033
4034 put_pid(pid);
4035}
4036
4037static void set_ftrace_pid(struct pid *pid)
4038{
4039 struct task_struct *p;
4040
4041 rcu_read_lock();
4042 do_each_pid_task(pid, PIDTYPE_PID, p) {
4043 set_tsk_trace_trace(p);
4044 } while_each_pid_task(pid, PIDTYPE_PID, p);
4045 rcu_read_unlock();
4046}
4047
4048static void clear_ftrace_pid_task(struct pid *pid)
4049{
4050 if (pid == ftrace_swapper_pid)
4051 clear_ftrace_swapper();
4052 else
4053 clear_ftrace_pid(pid);
4054}
4055
4056static void set_ftrace_pid_task(struct pid *pid)
4057{
4058 if (pid == ftrace_swapper_pid)
4059 set_ftrace_swapper();
4060 else
4061 set_ftrace_pid(pid);
4062}
4063
4064static int ftrace_pid_add(int p)
4065{
4066 struct pid *pid;
4067 struct ftrace_pid *fpid;
4068 int ret = -EINVAL;
4069
4070 mutex_lock(&ftrace_lock);
4071
4072 if (!p)
4073 pid = ftrace_swapper_pid;
4074 else
4075 pid = find_get_pid(p);
4076
4077 if (!pid)
4078 goto out;
4079
4080 ret = 0;
4081
4082 list_for_each_entry(fpid, &ftrace_pids, list)
4083 if (fpid->pid == pid)
4084 goto out_put;
4085
4086 ret = -ENOMEM;
4087
4088 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4089 if (!fpid)
4090 goto out_put;
4091
4092 list_add(&fpid->list, &ftrace_pids);
4093 fpid->pid = pid;
4094
4095 set_ftrace_pid_task(pid);
4096
4097 ftrace_update_pid_func();
4098 ftrace_startup_enable(0);
4099
4100 mutex_unlock(&ftrace_lock);
4101 return 0;
4102
4103out_put:
4104 if (pid != ftrace_swapper_pid)
4105 put_pid(pid);
4106
4107out:
4108 mutex_unlock(&ftrace_lock);
4109 return ret;
4110}
4111
4112static void ftrace_pid_reset(void)
4113{
4114 struct ftrace_pid *fpid, *safe;
4115
4116 mutex_lock(&ftrace_lock);
4117 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4118 struct pid *pid = fpid->pid;
4119
4120 clear_ftrace_pid_task(pid);
4121
4122 list_del(&fpid->list);
4123 kfree(fpid);
4124 }
4125
4126 ftrace_update_pid_func();
4127 ftrace_startup_enable(0);
4128
4129 mutex_unlock(&ftrace_lock);
4130}
4131
4132static void *fpid_start(struct seq_file *m, loff_t *pos)
4133{
4134 mutex_lock(&ftrace_lock);
4135
4136 if (list_empty(&ftrace_pids) && (!*pos))
4137 return (void *) 1;
4138
4139 return seq_list_start(&ftrace_pids, *pos);
4140}
4141
4142static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4143{
4144 if (v == (void *)1)
4145 return NULL;
4146
4147 return seq_list_next(v, &ftrace_pids, pos);
4148}
4149
4150static void fpid_stop(struct seq_file *m, void *p)
4151{
4152 mutex_unlock(&ftrace_lock);
4153}
4154
4155static int fpid_show(struct seq_file *m, void *v)
4156{
4157 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4158
4159 if (v == (void *)1) {
4160 seq_printf(m, "no pid\n");
4161 return 0;
4162 }
4163
4164 if (fpid->pid == ftrace_swapper_pid)
4165 seq_printf(m, "swapper tasks\n");
4166 else
4167 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4168
4169 return 0;
4170}
4171
4172static const struct seq_operations ftrace_pid_sops = {
4173 .start = fpid_start,
4174 .next = fpid_next,
4175 .stop = fpid_stop,
4176 .show = fpid_show,
4177};
4178
4179static int
4180ftrace_pid_open(struct inode *inode, struct file *file)
4181{
4182 int ret = 0;
4183
4184 if ((file->f_mode & FMODE_WRITE) &&
4185 (file->f_flags & O_TRUNC))
4186 ftrace_pid_reset();
4187
4188 if (file->f_mode & FMODE_READ)
4189 ret = seq_open(file, &ftrace_pid_sops);
4190
4191 return ret;
4192}
4193
4194static ssize_t
4195ftrace_pid_write(struct file *filp, const char __user *ubuf,
4196 size_t cnt, loff_t *ppos)
4197{
4198 char buf[64], *tmp;
4199 long val;
4200 int ret;
4201
4202 if (cnt >= sizeof(buf))
4203 return -EINVAL;
4204
4205 if (copy_from_user(&buf, ubuf, cnt))
4206 return -EFAULT;
4207
4208 buf[cnt] = 0;
4209
4210 /*
4211 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4212 * to clean the filter quietly.
4213 */
4214 tmp = strstrip(buf);
4215 if (strlen(tmp) == 0)
4216 return 1;
4217
4218 ret = strict_strtol(tmp, 10, &val);
4219 if (ret < 0)
4220 return ret;
4221
4222 ret = ftrace_pid_add(val);
4223
4224 return ret ? ret : cnt;
4225}
4226
4227static int
4228ftrace_pid_release(struct inode *inode, struct file *file)
4229{
4230 if (file->f_mode & FMODE_READ)
4231 seq_release(inode, file);
4232
4233 return 0;
4234}
4235
4236static const struct file_operations ftrace_pid_fops = {
4237 .open = ftrace_pid_open,
4238 .write = ftrace_pid_write,
4239 .read = seq_read,
4240 .llseek = seq_lseek,
4241 .release = ftrace_pid_release,
4242};
4243
4244static __init int ftrace_init_debugfs(void)
4245{
4246 struct dentry *d_tracer;
4247
4248 d_tracer = tracing_init_dentry();
4249 if (!d_tracer)
4250 return 0;
4251
4252 ftrace_init_dyn_debugfs(d_tracer);
4253
4254 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4255 NULL, &ftrace_pid_fops);
4256
4257 ftrace_profile_debugfs(d_tracer);
4258
4259 return 0;
4260}
4261fs_initcall(ftrace_init_debugfs);
4262
4263/**
4264 * ftrace_kill - kill ftrace
4265 *
4266 * This function should be used by panic code. It stops ftrace
4267 * but in a not so nice way. If you need to simply kill ftrace
4268 * from a non-atomic section, use ftrace_kill.
4269 */
4270void ftrace_kill(void)
4271{
4272 ftrace_disabled = 1;
4273 ftrace_enabled = 0;
4274 clear_ftrace_function();
4275}
4276
4277/**
4278 * Test if ftrace is dead or not.
4279 */
4280int ftrace_is_dead(void)
4281{
4282 return ftrace_disabled;
4283}
4284
4285/**
4286 * register_ftrace_function - register a function for profiling
4287 * @ops - ops structure that holds the function for profiling.
4288 *
4289 * Register a function to be called by all functions in the
4290 * kernel.
4291 *
4292 * Note: @ops->func and all the functions it calls must be labeled
4293 * with "notrace", otherwise it will go into a
4294 * recursive loop.
4295 */
4296int register_ftrace_function(struct ftrace_ops *ops)
4297{
4298 int ret = -1;
4299
4300 mutex_lock(&ftrace_lock);
4301
4302 if (unlikely(ftrace_disabled))
4303 goto out_unlock;
4304
4305 ret = __register_ftrace_function(ops);
4306 if (!ret)
4307 ret = ftrace_startup(ops, 0);
4308
4309
4310 out_unlock:
4311 mutex_unlock(&ftrace_lock);
4312 return ret;
4313}
4314EXPORT_SYMBOL_GPL(register_ftrace_function);
4315
4316/**
4317 * unregister_ftrace_function - unregister a function for profiling.
4318 * @ops - ops structure that holds the function to unregister
4319 *
4320 * Unregister a function that was added to be called by ftrace profiling.
4321 */
4322int unregister_ftrace_function(struct ftrace_ops *ops)
4323{
4324 int ret;
4325
4326 mutex_lock(&ftrace_lock);
4327 ret = __unregister_ftrace_function(ops);
4328 if (!ret)
4329 ftrace_shutdown(ops, 0);
4330 mutex_unlock(&ftrace_lock);
4331
4332 return ret;
4333}
4334EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4335
4336int
4337ftrace_enable_sysctl(struct ctl_table *table, int write,
4338 void __user *buffer, size_t *lenp,
4339 loff_t *ppos)
4340{
4341 int ret = -ENODEV;
4342
4343 mutex_lock(&ftrace_lock);
4344
4345 if (unlikely(ftrace_disabled))
4346 goto out;
4347
4348 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4349
4350 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4351 goto out;
4352
4353 last_ftrace_enabled = !!ftrace_enabled;
4354
4355 if (ftrace_enabled) {
4356
4357 ftrace_startup_sysctl();
4358
4359 /* we are starting ftrace again */
4360 if (ftrace_ops_list != &ftrace_list_end) {
4361 if (ftrace_ops_list->next == &ftrace_list_end)
4362 ftrace_trace_function = ftrace_ops_list->func;
4363 else
4364 ftrace_trace_function = ftrace_ops_list_func;
4365 }
4366
4367 } else {
4368 /* stopping ftrace calls (just send to ftrace_stub) */
4369 ftrace_trace_function = ftrace_stub;
4370
4371 ftrace_shutdown_sysctl();
4372 }
4373
4374 out:
4375 mutex_unlock(&ftrace_lock);
4376 return ret;
4377}
4378
4379#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4380
4381static int ftrace_graph_active;
4382static struct notifier_block ftrace_suspend_notifier;
4383
4384int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4385{
4386 return 0;
4387}
4388
4389/* The callbacks that hook a function */
4390trace_func_graph_ret_t ftrace_graph_return =
4391 (trace_func_graph_ret_t)ftrace_stub;
4392trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4393
4394/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4395static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4396{
4397 int i;
4398 int ret = 0;
4399 unsigned long flags;
4400 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4401 struct task_struct *g, *t;
4402
4403 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4404 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4405 * sizeof(struct ftrace_ret_stack),
4406 GFP_KERNEL);
4407 if (!ret_stack_list[i]) {
4408 start = 0;
4409 end = i;
4410 ret = -ENOMEM;
4411 goto free;
4412 }
4413 }
4414
4415 read_lock_irqsave(&tasklist_lock, flags);
4416 do_each_thread(g, t) {
4417 if (start == end) {
4418 ret = -EAGAIN;
4419 goto unlock;
4420 }
4421
4422 if (t->ret_stack == NULL) {
4423 atomic_set(&t->tracing_graph_pause, 0);
4424 atomic_set(&t->trace_overrun, 0);
4425 t->curr_ret_stack = -1;
4426 /* Make sure the tasks see the -1 first: */
4427 smp_wmb();
4428 t->ret_stack = ret_stack_list[start++];
4429 }
4430 } while_each_thread(g, t);
4431
4432unlock:
4433 read_unlock_irqrestore(&tasklist_lock, flags);
4434free:
4435 for (i = start; i < end; i++)
4436 kfree(ret_stack_list[i]);
4437 return ret;
4438}
4439
4440static void
4441ftrace_graph_probe_sched_switch(void *ignore,
4442 struct task_struct *prev, struct task_struct *next)
4443{
4444 unsigned long long timestamp;
4445 int index;
4446
4447 /*
4448 * Does the user want to count the time a function was asleep.
4449 * If so, do not update the time stamps.
4450 */
4451 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4452 return;
4453
4454 timestamp = trace_clock_local();
4455
4456 prev->ftrace_timestamp = timestamp;
4457
4458 /* only process tasks that we timestamped */
4459 if (!next->ftrace_timestamp)
4460 return;
4461
4462 /*
4463 * Update all the counters in next to make up for the
4464 * time next was sleeping.
4465 */
4466 timestamp -= next->ftrace_timestamp;
4467
4468 for (index = next->curr_ret_stack; index >= 0; index--)
4469 next->ret_stack[index].calltime += timestamp;
4470}
4471
4472/* Allocate a return stack for each task */
4473static int start_graph_tracing(void)
4474{
4475 struct ftrace_ret_stack **ret_stack_list;
4476 int ret, cpu;
4477
4478 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4479 sizeof(struct ftrace_ret_stack *),
4480 GFP_KERNEL);
4481
4482 if (!ret_stack_list)
4483 return -ENOMEM;
4484
4485 /* The cpu_boot init_task->ret_stack will never be freed */
4486 for_each_online_cpu(cpu) {
4487 if (!idle_task(cpu)->ret_stack)
4488 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4489 }
4490
4491 do {
4492 ret = alloc_retstack_tasklist(ret_stack_list);
4493 } while (ret == -EAGAIN);
4494
4495 if (!ret) {
4496 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4497 if (ret)
4498 pr_info("ftrace_graph: Couldn't activate tracepoint"
4499 " probe to kernel_sched_switch\n");
4500 }
4501
4502 kfree(ret_stack_list);
4503 return ret;
4504}
4505
4506/*
4507 * Hibernation protection.
4508 * The state of the current task is too much unstable during
4509 * suspend/restore to disk. We want to protect against that.
4510 */
4511static int
4512ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4513 void *unused)
4514{
4515 switch (state) {
4516 case PM_HIBERNATION_PREPARE:
4517 pause_graph_tracing();
4518 break;
4519
4520 case PM_POST_HIBERNATION:
4521 unpause_graph_tracing();
4522 break;
4523 }
4524 return NOTIFY_DONE;
4525}
4526
4527int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4528 trace_func_graph_ent_t entryfunc)
4529{
4530 int ret = 0;
4531
4532 mutex_lock(&ftrace_lock);
4533
4534 /* we currently allow only one tracer registered at a time */
4535 if (ftrace_graph_active) {
4536 ret = -EBUSY;
4537 goto out;
4538 }
4539
4540 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4541 register_pm_notifier(&ftrace_suspend_notifier);
4542
4543 ftrace_graph_active++;
4544 ret = start_graph_tracing();
4545 if (ret) {
4546 ftrace_graph_active--;
4547 goto out;
4548 }
4549
4550 ftrace_graph_return = retfunc;
4551 ftrace_graph_entry = entryfunc;
4552
4553 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4554
4555out:
4556 mutex_unlock(&ftrace_lock);
4557 return ret;
4558}
4559
4560void unregister_ftrace_graph(void)
4561{
4562 mutex_lock(&ftrace_lock);
4563
4564 if (unlikely(!ftrace_graph_active))
4565 goto out;
4566
4567 ftrace_graph_active--;
4568 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4569 ftrace_graph_entry = ftrace_graph_entry_stub;
4570 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4571 unregister_pm_notifier(&ftrace_suspend_notifier);
4572 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4573
4574 out:
4575 mutex_unlock(&ftrace_lock);
4576}
4577
4578static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4579
4580static void
4581graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4582{
4583 atomic_set(&t->tracing_graph_pause, 0);
4584 atomic_set(&t->trace_overrun, 0);
4585 t->ftrace_timestamp = 0;
4586 /* make curr_ret_stack visible before we add the ret_stack */
4587 smp_wmb();
4588 t->ret_stack = ret_stack;
4589}
4590
4591/*
4592 * Allocate a return stack for the idle task. May be the first
4593 * time through, or it may be done by CPU hotplug online.
4594 */
4595void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4596{
4597 t->curr_ret_stack = -1;
4598 /*
4599 * The idle task has no parent, it either has its own
4600 * stack or no stack at all.
4601 */
4602 if (t->ret_stack)
4603 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4604
4605 if (ftrace_graph_active) {
4606 struct ftrace_ret_stack *ret_stack;
4607
4608 ret_stack = per_cpu(idle_ret_stack, cpu);
4609 if (!ret_stack) {
4610 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4611 * sizeof(struct ftrace_ret_stack),
4612 GFP_KERNEL);
4613 if (!ret_stack)
4614 return;
4615 per_cpu(idle_ret_stack, cpu) = ret_stack;
4616 }
4617 graph_init_task(t, ret_stack);
4618 }
4619}
4620
4621/* Allocate a return stack for newly created task */
4622void ftrace_graph_init_task(struct task_struct *t)
4623{
4624 /* Make sure we do not use the parent ret_stack */
4625 t->ret_stack = NULL;
4626 t->curr_ret_stack = -1;
4627
4628 if (ftrace_graph_active) {
4629 struct ftrace_ret_stack *ret_stack;
4630
4631 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4632 * sizeof(struct ftrace_ret_stack),
4633 GFP_KERNEL);
4634 if (!ret_stack)
4635 return;
4636 graph_init_task(t, ret_stack);
4637 }
4638}
4639
4640void ftrace_graph_exit_task(struct task_struct *t)
4641{
4642 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4643
4644 t->ret_stack = NULL;
4645 /* NULL must become visible to IRQs before we free it: */
4646 barrier();
4647
4648 kfree(ret_stack);
4649}
4650
4651void ftrace_graph_stop(void)
4652{
4653 ftrace_stop();
4654}
4655#endif
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 Nadia Yvette Chambers
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/tracefs.h>
22#include <linux/hardirq.h>
23#include <linux/kthread.h>
24#include <linux/uaccess.h>
25#include <linux/bsearch.h>
26#include <linux/module.h>
27#include <linux/ftrace.h>
28#include <linux/sysctl.h>
29#include <linux/slab.h>
30#include <linux/ctype.h>
31#include <linux/sort.h>
32#include <linux/list.h>
33#include <linux/hash.h>
34#include <linux/rcupdate.h>
35
36#include <trace/events/sched.h>
37
38#include <asm/setup.h>
39
40#include "trace_output.h"
41#include "trace_stat.h"
42
43#define FTRACE_WARN_ON(cond) \
44 ({ \
45 int ___r = cond; \
46 if (WARN_ON(___r)) \
47 ftrace_kill(); \
48 ___r; \
49 })
50
51#define FTRACE_WARN_ON_ONCE(cond) \
52 ({ \
53 int ___r = cond; \
54 if (WARN_ON_ONCE(___r)) \
55 ftrace_kill(); \
56 ___r; \
57 })
58
59/* hash bits for specific function selection */
60#define FTRACE_HASH_BITS 7
61#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62#define FTRACE_HASH_DEFAULT_BITS 10
63#define FTRACE_HASH_MAX_BITS 12
64
65#ifdef CONFIG_DYNAMIC_FTRACE
66#define INIT_OPS_HASH(opsname) \
67 .func_hash = &opsname.local_hash, \
68 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
69#define ASSIGN_OPS_HASH(opsname, val) \
70 .func_hash = val, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
72#else
73#define INIT_OPS_HASH(opsname)
74#define ASSIGN_OPS_HASH(opsname, val)
75#endif
76
77static struct ftrace_ops ftrace_list_end __read_mostly = {
78 .func = ftrace_stub,
79 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
80 INIT_OPS_HASH(ftrace_list_end)
81};
82
83/* ftrace_enabled is a method to turn ftrace on or off */
84int ftrace_enabled __read_mostly;
85static int last_ftrace_enabled;
86
87/* Current function tracing op */
88struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
89/* What to set function_trace_op to */
90static struct ftrace_ops *set_function_trace_op;
91
92/* List for set_ftrace_pid's pids. */
93LIST_HEAD(ftrace_pids);
94struct ftrace_pid {
95 struct list_head list;
96 struct pid *pid;
97};
98
99static bool ftrace_pids_enabled(void)
100{
101 return !list_empty(&ftrace_pids);
102}
103
104static void ftrace_update_trampoline(struct ftrace_ops *ops);
105
106/*
107 * ftrace_disabled is set when an anomaly is discovered.
108 * ftrace_disabled is much stronger than ftrace_enabled.
109 */
110static int ftrace_disabled __read_mostly;
111
112static DEFINE_MUTEX(ftrace_lock);
113
114static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
115ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
116static struct ftrace_ops global_ops;
117
118#if ARCH_SUPPORTS_FTRACE_OPS
119static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
120 struct ftrace_ops *op, struct pt_regs *regs);
121#else
122/* See comment below, where ftrace_ops_list_func is defined */
123static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
124#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
125#endif
126
127/*
128 * Traverse the ftrace_global_list, invoking all entries. The reason that we
129 * can use rcu_dereference_raw_notrace() is that elements removed from this list
130 * are simply leaked, so there is no need to interact with a grace-period
131 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
132 * concurrent insertions into the ftrace_global_list.
133 *
134 * Silly Alpha and silly pointer-speculation compiler optimizations!
135 */
136#define do_for_each_ftrace_op(op, list) \
137 op = rcu_dereference_raw_notrace(list); \
138 do
139
140/*
141 * Optimized for just a single item in the list (as that is the normal case).
142 */
143#define while_for_each_ftrace_op(op) \
144 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
145 unlikely((op) != &ftrace_list_end))
146
147static inline void ftrace_ops_init(struct ftrace_ops *ops)
148{
149#ifdef CONFIG_DYNAMIC_FTRACE
150 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
151 mutex_init(&ops->local_hash.regex_lock);
152 ops->func_hash = &ops->local_hash;
153 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
154 }
155#endif
156}
157
158/**
159 * ftrace_nr_registered_ops - return number of ops registered
160 *
161 * Returns the number of ftrace_ops registered and tracing functions
162 */
163int ftrace_nr_registered_ops(void)
164{
165 struct ftrace_ops *ops;
166 int cnt = 0;
167
168 mutex_lock(&ftrace_lock);
169
170 for (ops = ftrace_ops_list;
171 ops != &ftrace_list_end; ops = ops->next)
172 cnt++;
173
174 mutex_unlock(&ftrace_lock);
175
176 return cnt;
177}
178
179static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
180 struct ftrace_ops *op, struct pt_regs *regs)
181{
182 if (!test_tsk_trace_trace(current))
183 return;
184
185 op->saved_func(ip, parent_ip, op, regs);
186}
187
188/**
189 * clear_ftrace_function - reset the ftrace function
190 *
191 * This NULLs the ftrace function and in essence stops
192 * tracing. There may be lag
193 */
194void clear_ftrace_function(void)
195{
196 ftrace_trace_function = ftrace_stub;
197}
198
199static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
200{
201 int cpu;
202
203 for_each_possible_cpu(cpu)
204 *per_cpu_ptr(ops->disabled, cpu) = 1;
205}
206
207static int per_cpu_ops_alloc(struct ftrace_ops *ops)
208{
209 int __percpu *disabled;
210
211 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
212 return -EINVAL;
213
214 disabled = alloc_percpu(int);
215 if (!disabled)
216 return -ENOMEM;
217
218 ops->disabled = disabled;
219 per_cpu_ops_disable_all(ops);
220 return 0;
221}
222
223static void ftrace_sync(struct work_struct *work)
224{
225 /*
226 * This function is just a stub to implement a hard force
227 * of synchronize_sched(). This requires synchronizing
228 * tasks even in userspace and idle.
229 *
230 * Yes, function tracing is rude.
231 */
232}
233
234static void ftrace_sync_ipi(void *data)
235{
236 /* Probably not needed, but do it anyway */
237 smp_rmb();
238}
239
240#ifdef CONFIG_FUNCTION_GRAPH_TRACER
241static void update_function_graph_func(void);
242
243/* Both enabled by default (can be cleared by function_graph tracer flags */
244static bool fgraph_sleep_time = true;
245static bool fgraph_graph_time = true;
246
247#else
248static inline void update_function_graph_func(void) { }
249#endif
250
251
252static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
253{
254 /*
255 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
256 * then it needs to call the list anyway.
257 */
258 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
259 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
260 return ftrace_ops_list_func;
261
262 return ftrace_ops_get_func(ops);
263}
264
265static void update_ftrace_function(void)
266{
267 ftrace_func_t func;
268
269 /*
270 * Prepare the ftrace_ops that the arch callback will use.
271 * If there's only one ftrace_ops registered, the ftrace_ops_list
272 * will point to the ops we want.
273 */
274 set_function_trace_op = ftrace_ops_list;
275
276 /* If there's no ftrace_ops registered, just call the stub function */
277 if (ftrace_ops_list == &ftrace_list_end) {
278 func = ftrace_stub;
279
280 /*
281 * If we are at the end of the list and this ops is
282 * recursion safe and not dynamic and the arch supports passing ops,
283 * then have the mcount trampoline call the function directly.
284 */
285 } else if (ftrace_ops_list->next == &ftrace_list_end) {
286 func = ftrace_ops_get_list_func(ftrace_ops_list);
287
288 } else {
289 /* Just use the default ftrace_ops */
290 set_function_trace_op = &ftrace_list_end;
291 func = ftrace_ops_list_func;
292 }
293
294 update_function_graph_func();
295
296 /* If there's no change, then do nothing more here */
297 if (ftrace_trace_function == func)
298 return;
299
300 /*
301 * If we are using the list function, it doesn't care
302 * about the function_trace_ops.
303 */
304 if (func == ftrace_ops_list_func) {
305 ftrace_trace_function = func;
306 /*
307 * Don't even bother setting function_trace_ops,
308 * it would be racy to do so anyway.
309 */
310 return;
311 }
312
313#ifndef CONFIG_DYNAMIC_FTRACE
314 /*
315 * For static tracing, we need to be a bit more careful.
316 * The function change takes affect immediately. Thus,
317 * we need to coorditate the setting of the function_trace_ops
318 * with the setting of the ftrace_trace_function.
319 *
320 * Set the function to the list ops, which will call the
321 * function we want, albeit indirectly, but it handles the
322 * ftrace_ops and doesn't depend on function_trace_op.
323 */
324 ftrace_trace_function = ftrace_ops_list_func;
325 /*
326 * Make sure all CPUs see this. Yes this is slow, but static
327 * tracing is slow and nasty to have enabled.
328 */
329 schedule_on_each_cpu(ftrace_sync);
330 /* Now all cpus are using the list ops. */
331 function_trace_op = set_function_trace_op;
332 /* Make sure the function_trace_op is visible on all CPUs */
333 smp_wmb();
334 /* Nasty way to force a rmb on all cpus */
335 smp_call_function(ftrace_sync_ipi, NULL, 1);
336 /* OK, we are all set to update the ftrace_trace_function now! */
337#endif /* !CONFIG_DYNAMIC_FTRACE */
338
339 ftrace_trace_function = func;
340}
341
342int using_ftrace_ops_list_func(void)
343{
344 return ftrace_trace_function == ftrace_ops_list_func;
345}
346
347static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
348{
349 ops->next = *list;
350 /*
351 * We are entering ops into the list but another
352 * CPU might be walking that list. We need to make sure
353 * the ops->next pointer is valid before another CPU sees
354 * the ops pointer included into the list.
355 */
356 rcu_assign_pointer(*list, ops);
357}
358
359static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
360{
361 struct ftrace_ops **p;
362
363 /*
364 * If we are removing the last function, then simply point
365 * to the ftrace_stub.
366 */
367 if (*list == ops && ops->next == &ftrace_list_end) {
368 *list = &ftrace_list_end;
369 return 0;
370 }
371
372 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
373 if (*p == ops)
374 break;
375
376 if (*p != ops)
377 return -1;
378
379 *p = (*p)->next;
380 return 0;
381}
382
383static void ftrace_update_trampoline(struct ftrace_ops *ops);
384
385static int __register_ftrace_function(struct ftrace_ops *ops)
386{
387 if (ops->flags & FTRACE_OPS_FL_DELETED)
388 return -EINVAL;
389
390 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
391 return -EBUSY;
392
393#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
394 /*
395 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
396 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
397 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
398 */
399 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
400 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
401 return -EINVAL;
402
403 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
404 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
405#endif
406
407 if (!core_kernel_data((unsigned long)ops))
408 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
409
410 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
411 if (per_cpu_ops_alloc(ops))
412 return -ENOMEM;
413 }
414
415 add_ftrace_ops(&ftrace_ops_list, ops);
416
417 /* Always save the function, and reset at unregistering */
418 ops->saved_func = ops->func;
419
420 if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
421 ops->func = ftrace_pid_func;
422
423 ftrace_update_trampoline(ops);
424
425 if (ftrace_enabled)
426 update_ftrace_function();
427
428 return 0;
429}
430
431static int __unregister_ftrace_function(struct ftrace_ops *ops)
432{
433 int ret;
434
435 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
436 return -EBUSY;
437
438 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
439
440 if (ret < 0)
441 return ret;
442
443 if (ftrace_enabled)
444 update_ftrace_function();
445
446 ops->func = ops->saved_func;
447
448 return 0;
449}
450
451static void ftrace_update_pid_func(void)
452{
453 bool enabled = ftrace_pids_enabled();
454 struct ftrace_ops *op;
455
456 /* Only do something if we are tracing something */
457 if (ftrace_trace_function == ftrace_stub)
458 return;
459
460 do_for_each_ftrace_op(op, ftrace_ops_list) {
461 if (op->flags & FTRACE_OPS_FL_PID) {
462 op->func = enabled ? ftrace_pid_func :
463 op->saved_func;
464 ftrace_update_trampoline(op);
465 }
466 } while_for_each_ftrace_op(op);
467
468 update_ftrace_function();
469}
470
471#ifdef CONFIG_FUNCTION_PROFILER
472struct ftrace_profile {
473 struct hlist_node node;
474 unsigned long ip;
475 unsigned long counter;
476#ifdef CONFIG_FUNCTION_GRAPH_TRACER
477 unsigned long long time;
478 unsigned long long time_squared;
479#endif
480};
481
482struct ftrace_profile_page {
483 struct ftrace_profile_page *next;
484 unsigned long index;
485 struct ftrace_profile records[];
486};
487
488struct ftrace_profile_stat {
489 atomic_t disabled;
490 struct hlist_head *hash;
491 struct ftrace_profile_page *pages;
492 struct ftrace_profile_page *start;
493 struct tracer_stat stat;
494};
495
496#define PROFILE_RECORDS_SIZE \
497 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
498
499#define PROFILES_PER_PAGE \
500 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
501
502static int ftrace_profile_enabled __read_mostly;
503
504/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
505static DEFINE_MUTEX(ftrace_profile_lock);
506
507static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
508
509#define FTRACE_PROFILE_HASH_BITS 10
510#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
511
512static void *
513function_stat_next(void *v, int idx)
514{
515 struct ftrace_profile *rec = v;
516 struct ftrace_profile_page *pg;
517
518 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
519
520 again:
521 if (idx != 0)
522 rec++;
523
524 if ((void *)rec >= (void *)&pg->records[pg->index]) {
525 pg = pg->next;
526 if (!pg)
527 return NULL;
528 rec = &pg->records[0];
529 if (!rec->counter)
530 goto again;
531 }
532
533 return rec;
534}
535
536static void *function_stat_start(struct tracer_stat *trace)
537{
538 struct ftrace_profile_stat *stat =
539 container_of(trace, struct ftrace_profile_stat, stat);
540
541 if (!stat || !stat->start)
542 return NULL;
543
544 return function_stat_next(&stat->start->records[0], 0);
545}
546
547#ifdef CONFIG_FUNCTION_GRAPH_TRACER
548/* function graph compares on total time */
549static int function_stat_cmp(void *p1, void *p2)
550{
551 struct ftrace_profile *a = p1;
552 struct ftrace_profile *b = p2;
553
554 if (a->time < b->time)
555 return -1;
556 if (a->time > b->time)
557 return 1;
558 else
559 return 0;
560}
561#else
562/* not function graph compares against hits */
563static int function_stat_cmp(void *p1, void *p2)
564{
565 struct ftrace_profile *a = p1;
566 struct ftrace_profile *b = p2;
567
568 if (a->counter < b->counter)
569 return -1;
570 if (a->counter > b->counter)
571 return 1;
572 else
573 return 0;
574}
575#endif
576
577static int function_stat_headers(struct seq_file *m)
578{
579#ifdef CONFIG_FUNCTION_GRAPH_TRACER
580 seq_puts(m, " Function "
581 "Hit Time Avg s^2\n"
582 " -------- "
583 "--- ---- --- ---\n");
584#else
585 seq_puts(m, " Function Hit\n"
586 " -------- ---\n");
587#endif
588 return 0;
589}
590
591static int function_stat_show(struct seq_file *m, void *v)
592{
593 struct ftrace_profile *rec = v;
594 char str[KSYM_SYMBOL_LEN];
595 int ret = 0;
596#ifdef CONFIG_FUNCTION_GRAPH_TRACER
597 static struct trace_seq s;
598 unsigned long long avg;
599 unsigned long long stddev;
600#endif
601 mutex_lock(&ftrace_profile_lock);
602
603 /* we raced with function_profile_reset() */
604 if (unlikely(rec->counter == 0)) {
605 ret = -EBUSY;
606 goto out;
607 }
608
609#ifdef CONFIG_FUNCTION_GRAPH_TRACER
610 avg = rec->time;
611 do_div(avg, rec->counter);
612 if (tracing_thresh && (avg < tracing_thresh))
613 goto out;
614#endif
615
616 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
617 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
618
619#ifdef CONFIG_FUNCTION_GRAPH_TRACER
620 seq_puts(m, " ");
621
622 /* Sample standard deviation (s^2) */
623 if (rec->counter <= 1)
624 stddev = 0;
625 else {
626 /*
627 * Apply Welford's method:
628 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
629 */
630 stddev = rec->counter * rec->time_squared -
631 rec->time * rec->time;
632
633 /*
634 * Divide only 1000 for ns^2 -> us^2 conversion.
635 * trace_print_graph_duration will divide 1000 again.
636 */
637 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
638 }
639
640 trace_seq_init(&s);
641 trace_print_graph_duration(rec->time, &s);
642 trace_seq_puts(&s, " ");
643 trace_print_graph_duration(avg, &s);
644 trace_seq_puts(&s, " ");
645 trace_print_graph_duration(stddev, &s);
646 trace_print_seq(m, &s);
647#endif
648 seq_putc(m, '\n');
649out:
650 mutex_unlock(&ftrace_profile_lock);
651
652 return ret;
653}
654
655static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
656{
657 struct ftrace_profile_page *pg;
658
659 pg = stat->pages = stat->start;
660
661 while (pg) {
662 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
663 pg->index = 0;
664 pg = pg->next;
665 }
666
667 memset(stat->hash, 0,
668 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
669}
670
671int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
672{
673 struct ftrace_profile_page *pg;
674 int functions;
675 int pages;
676 int i;
677
678 /* If we already allocated, do nothing */
679 if (stat->pages)
680 return 0;
681
682 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
683 if (!stat->pages)
684 return -ENOMEM;
685
686#ifdef CONFIG_DYNAMIC_FTRACE
687 functions = ftrace_update_tot_cnt;
688#else
689 /*
690 * We do not know the number of functions that exist because
691 * dynamic tracing is what counts them. With past experience
692 * we have around 20K functions. That should be more than enough.
693 * It is highly unlikely we will execute every function in
694 * the kernel.
695 */
696 functions = 20000;
697#endif
698
699 pg = stat->start = stat->pages;
700
701 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
702
703 for (i = 1; i < pages; i++) {
704 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
705 if (!pg->next)
706 goto out_free;
707 pg = pg->next;
708 }
709
710 return 0;
711
712 out_free:
713 pg = stat->start;
714 while (pg) {
715 unsigned long tmp = (unsigned long)pg;
716
717 pg = pg->next;
718 free_page(tmp);
719 }
720
721 stat->pages = NULL;
722 stat->start = NULL;
723
724 return -ENOMEM;
725}
726
727static int ftrace_profile_init_cpu(int cpu)
728{
729 struct ftrace_profile_stat *stat;
730 int size;
731
732 stat = &per_cpu(ftrace_profile_stats, cpu);
733
734 if (stat->hash) {
735 /* If the profile is already created, simply reset it */
736 ftrace_profile_reset(stat);
737 return 0;
738 }
739
740 /*
741 * We are profiling all functions, but usually only a few thousand
742 * functions are hit. We'll make a hash of 1024 items.
743 */
744 size = FTRACE_PROFILE_HASH_SIZE;
745
746 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
747
748 if (!stat->hash)
749 return -ENOMEM;
750
751 /* Preallocate the function profiling pages */
752 if (ftrace_profile_pages_init(stat) < 0) {
753 kfree(stat->hash);
754 stat->hash = NULL;
755 return -ENOMEM;
756 }
757
758 return 0;
759}
760
761static int ftrace_profile_init(void)
762{
763 int cpu;
764 int ret = 0;
765
766 for_each_possible_cpu(cpu) {
767 ret = ftrace_profile_init_cpu(cpu);
768 if (ret)
769 break;
770 }
771
772 return ret;
773}
774
775/* interrupts must be disabled */
776static struct ftrace_profile *
777ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
778{
779 struct ftrace_profile *rec;
780 struct hlist_head *hhd;
781 unsigned long key;
782
783 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
784 hhd = &stat->hash[key];
785
786 if (hlist_empty(hhd))
787 return NULL;
788
789 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
790 if (rec->ip == ip)
791 return rec;
792 }
793
794 return NULL;
795}
796
797static void ftrace_add_profile(struct ftrace_profile_stat *stat,
798 struct ftrace_profile *rec)
799{
800 unsigned long key;
801
802 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
803 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
804}
805
806/*
807 * The memory is already allocated, this simply finds a new record to use.
808 */
809static struct ftrace_profile *
810ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
811{
812 struct ftrace_profile *rec = NULL;
813
814 /* prevent recursion (from NMIs) */
815 if (atomic_inc_return(&stat->disabled) != 1)
816 goto out;
817
818 /*
819 * Try to find the function again since an NMI
820 * could have added it
821 */
822 rec = ftrace_find_profiled_func(stat, ip);
823 if (rec)
824 goto out;
825
826 if (stat->pages->index == PROFILES_PER_PAGE) {
827 if (!stat->pages->next)
828 goto out;
829 stat->pages = stat->pages->next;
830 }
831
832 rec = &stat->pages->records[stat->pages->index++];
833 rec->ip = ip;
834 ftrace_add_profile(stat, rec);
835
836 out:
837 atomic_dec(&stat->disabled);
838
839 return rec;
840}
841
842static void
843function_profile_call(unsigned long ip, unsigned long parent_ip,
844 struct ftrace_ops *ops, struct pt_regs *regs)
845{
846 struct ftrace_profile_stat *stat;
847 struct ftrace_profile *rec;
848 unsigned long flags;
849
850 if (!ftrace_profile_enabled)
851 return;
852
853 local_irq_save(flags);
854
855 stat = this_cpu_ptr(&ftrace_profile_stats);
856 if (!stat->hash || !ftrace_profile_enabled)
857 goto out;
858
859 rec = ftrace_find_profiled_func(stat, ip);
860 if (!rec) {
861 rec = ftrace_profile_alloc(stat, ip);
862 if (!rec)
863 goto out;
864 }
865
866 rec->counter++;
867 out:
868 local_irq_restore(flags);
869}
870
871#ifdef CONFIG_FUNCTION_GRAPH_TRACER
872static int profile_graph_entry(struct ftrace_graph_ent *trace)
873{
874 function_profile_call(trace->func, 0, NULL, NULL);
875 return 1;
876}
877
878static void profile_graph_return(struct ftrace_graph_ret *trace)
879{
880 struct ftrace_profile_stat *stat;
881 unsigned long long calltime;
882 struct ftrace_profile *rec;
883 unsigned long flags;
884
885 local_irq_save(flags);
886 stat = this_cpu_ptr(&ftrace_profile_stats);
887 if (!stat->hash || !ftrace_profile_enabled)
888 goto out;
889
890 /* If the calltime was zero'd ignore it */
891 if (!trace->calltime)
892 goto out;
893
894 calltime = trace->rettime - trace->calltime;
895
896 if (!fgraph_graph_time) {
897 int index;
898
899 index = trace->depth;
900
901 /* Append this call time to the parent time to subtract */
902 if (index)
903 current->ret_stack[index - 1].subtime += calltime;
904
905 if (current->ret_stack[index].subtime < calltime)
906 calltime -= current->ret_stack[index].subtime;
907 else
908 calltime = 0;
909 }
910
911 rec = ftrace_find_profiled_func(stat, trace->func);
912 if (rec) {
913 rec->time += calltime;
914 rec->time_squared += calltime * calltime;
915 }
916
917 out:
918 local_irq_restore(flags);
919}
920
921static int register_ftrace_profiler(void)
922{
923 return register_ftrace_graph(&profile_graph_return,
924 &profile_graph_entry);
925}
926
927static void unregister_ftrace_profiler(void)
928{
929 unregister_ftrace_graph();
930}
931#else
932static struct ftrace_ops ftrace_profile_ops __read_mostly = {
933 .func = function_profile_call,
934 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
935 INIT_OPS_HASH(ftrace_profile_ops)
936};
937
938static int register_ftrace_profiler(void)
939{
940 return register_ftrace_function(&ftrace_profile_ops);
941}
942
943static void unregister_ftrace_profiler(void)
944{
945 unregister_ftrace_function(&ftrace_profile_ops);
946}
947#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
948
949static ssize_t
950ftrace_profile_write(struct file *filp, const char __user *ubuf,
951 size_t cnt, loff_t *ppos)
952{
953 unsigned long val;
954 int ret;
955
956 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
957 if (ret)
958 return ret;
959
960 val = !!val;
961
962 mutex_lock(&ftrace_profile_lock);
963 if (ftrace_profile_enabled ^ val) {
964 if (val) {
965 ret = ftrace_profile_init();
966 if (ret < 0) {
967 cnt = ret;
968 goto out;
969 }
970
971 ret = register_ftrace_profiler();
972 if (ret < 0) {
973 cnt = ret;
974 goto out;
975 }
976 ftrace_profile_enabled = 1;
977 } else {
978 ftrace_profile_enabled = 0;
979 /*
980 * unregister_ftrace_profiler calls stop_machine
981 * so this acts like an synchronize_sched.
982 */
983 unregister_ftrace_profiler();
984 }
985 }
986 out:
987 mutex_unlock(&ftrace_profile_lock);
988
989 *ppos += cnt;
990
991 return cnt;
992}
993
994static ssize_t
995ftrace_profile_read(struct file *filp, char __user *ubuf,
996 size_t cnt, loff_t *ppos)
997{
998 char buf[64]; /* big enough to hold a number */
999 int r;
1000
1001 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1002 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1003}
1004
1005static const struct file_operations ftrace_profile_fops = {
1006 .open = tracing_open_generic,
1007 .read = ftrace_profile_read,
1008 .write = ftrace_profile_write,
1009 .llseek = default_llseek,
1010};
1011
1012/* used to initialize the real stat files */
1013static struct tracer_stat function_stats __initdata = {
1014 .name = "functions",
1015 .stat_start = function_stat_start,
1016 .stat_next = function_stat_next,
1017 .stat_cmp = function_stat_cmp,
1018 .stat_headers = function_stat_headers,
1019 .stat_show = function_stat_show
1020};
1021
1022static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1023{
1024 struct ftrace_profile_stat *stat;
1025 struct dentry *entry;
1026 char *name;
1027 int ret;
1028 int cpu;
1029
1030 for_each_possible_cpu(cpu) {
1031 stat = &per_cpu(ftrace_profile_stats, cpu);
1032
1033 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1034 if (!name) {
1035 /*
1036 * The files created are permanent, if something happens
1037 * we still do not free memory.
1038 */
1039 WARN(1,
1040 "Could not allocate stat file for cpu %d\n",
1041 cpu);
1042 return;
1043 }
1044 stat->stat = function_stats;
1045 stat->stat.name = name;
1046 ret = register_stat_tracer(&stat->stat);
1047 if (ret) {
1048 WARN(1,
1049 "Could not register function stat for cpu %d\n",
1050 cpu);
1051 kfree(name);
1052 return;
1053 }
1054 }
1055
1056 entry = tracefs_create_file("function_profile_enabled", 0644,
1057 d_tracer, NULL, &ftrace_profile_fops);
1058 if (!entry)
1059 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1060}
1061
1062#else /* CONFIG_FUNCTION_PROFILER */
1063static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1064{
1065}
1066#endif /* CONFIG_FUNCTION_PROFILER */
1067
1068static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1069
1070#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1071static int ftrace_graph_active;
1072#else
1073# define ftrace_graph_active 0
1074#endif
1075
1076#ifdef CONFIG_DYNAMIC_FTRACE
1077
1078static struct ftrace_ops *removed_ops;
1079
1080/*
1081 * Set when doing a global update, like enabling all recs or disabling them.
1082 * It is not set when just updating a single ftrace_ops.
1083 */
1084static bool update_all_ops;
1085
1086#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1087# error Dynamic ftrace depends on MCOUNT_RECORD
1088#endif
1089
1090static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1091
1092struct ftrace_func_probe {
1093 struct hlist_node node;
1094 struct ftrace_probe_ops *ops;
1095 unsigned long flags;
1096 unsigned long ip;
1097 void *data;
1098 struct list_head free_list;
1099};
1100
1101struct ftrace_func_entry {
1102 struct hlist_node hlist;
1103 unsigned long ip;
1104};
1105
1106struct ftrace_hash {
1107 unsigned long size_bits;
1108 struct hlist_head *buckets;
1109 unsigned long count;
1110 struct rcu_head rcu;
1111};
1112
1113/*
1114 * We make these constant because no one should touch them,
1115 * but they are used as the default "empty hash", to avoid allocating
1116 * it all the time. These are in a read only section such that if
1117 * anyone does try to modify it, it will cause an exception.
1118 */
1119static const struct hlist_head empty_buckets[1];
1120static const struct ftrace_hash empty_hash = {
1121 .buckets = (struct hlist_head *)empty_buckets,
1122};
1123#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1124
1125static struct ftrace_ops global_ops = {
1126 .func = ftrace_stub,
1127 .local_hash.notrace_hash = EMPTY_HASH,
1128 .local_hash.filter_hash = EMPTY_HASH,
1129 INIT_OPS_HASH(global_ops)
1130 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1131 FTRACE_OPS_FL_INITIALIZED |
1132 FTRACE_OPS_FL_PID,
1133};
1134
1135/*
1136 * This is used by __kernel_text_address() to return true if the
1137 * address is on a dynamically allocated trampoline that would
1138 * not return true for either core_kernel_text() or
1139 * is_module_text_address().
1140 */
1141bool is_ftrace_trampoline(unsigned long addr)
1142{
1143 struct ftrace_ops *op;
1144 bool ret = false;
1145
1146 /*
1147 * Some of the ops may be dynamically allocated,
1148 * they are freed after a synchronize_sched().
1149 */
1150 preempt_disable_notrace();
1151
1152 do_for_each_ftrace_op(op, ftrace_ops_list) {
1153 /*
1154 * This is to check for dynamically allocated trampolines.
1155 * Trampolines that are in kernel text will have
1156 * core_kernel_text() return true.
1157 */
1158 if (op->trampoline && op->trampoline_size)
1159 if (addr >= op->trampoline &&
1160 addr < op->trampoline + op->trampoline_size) {
1161 ret = true;
1162 goto out;
1163 }
1164 } while_for_each_ftrace_op(op);
1165
1166 out:
1167 preempt_enable_notrace();
1168
1169 return ret;
1170}
1171
1172struct ftrace_page {
1173 struct ftrace_page *next;
1174 struct dyn_ftrace *records;
1175 int index;
1176 int size;
1177};
1178
1179#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1180#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1181
1182/* estimate from running different kernels */
1183#define NR_TO_INIT 10000
1184
1185static struct ftrace_page *ftrace_pages_start;
1186static struct ftrace_page *ftrace_pages;
1187
1188static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1189{
1190 return !hash || !hash->count;
1191}
1192
1193static struct ftrace_func_entry *
1194ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1195{
1196 unsigned long key;
1197 struct ftrace_func_entry *entry;
1198 struct hlist_head *hhd;
1199
1200 if (ftrace_hash_empty(hash))
1201 return NULL;
1202
1203 if (hash->size_bits > 0)
1204 key = hash_long(ip, hash->size_bits);
1205 else
1206 key = 0;
1207
1208 hhd = &hash->buckets[key];
1209
1210 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1211 if (entry->ip == ip)
1212 return entry;
1213 }
1214 return NULL;
1215}
1216
1217static void __add_hash_entry(struct ftrace_hash *hash,
1218 struct ftrace_func_entry *entry)
1219{
1220 struct hlist_head *hhd;
1221 unsigned long key;
1222
1223 if (hash->size_bits)
1224 key = hash_long(entry->ip, hash->size_bits);
1225 else
1226 key = 0;
1227
1228 hhd = &hash->buckets[key];
1229 hlist_add_head(&entry->hlist, hhd);
1230 hash->count++;
1231}
1232
1233static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1234{
1235 struct ftrace_func_entry *entry;
1236
1237 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1238 if (!entry)
1239 return -ENOMEM;
1240
1241 entry->ip = ip;
1242 __add_hash_entry(hash, entry);
1243
1244 return 0;
1245}
1246
1247static void
1248free_hash_entry(struct ftrace_hash *hash,
1249 struct ftrace_func_entry *entry)
1250{
1251 hlist_del(&entry->hlist);
1252 kfree(entry);
1253 hash->count--;
1254}
1255
1256static void
1257remove_hash_entry(struct ftrace_hash *hash,
1258 struct ftrace_func_entry *entry)
1259{
1260 hlist_del(&entry->hlist);
1261 hash->count--;
1262}
1263
1264static void ftrace_hash_clear(struct ftrace_hash *hash)
1265{
1266 struct hlist_head *hhd;
1267 struct hlist_node *tn;
1268 struct ftrace_func_entry *entry;
1269 int size = 1 << hash->size_bits;
1270 int i;
1271
1272 if (!hash->count)
1273 return;
1274
1275 for (i = 0; i < size; i++) {
1276 hhd = &hash->buckets[i];
1277 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1278 free_hash_entry(hash, entry);
1279 }
1280 FTRACE_WARN_ON(hash->count);
1281}
1282
1283static void free_ftrace_hash(struct ftrace_hash *hash)
1284{
1285 if (!hash || hash == EMPTY_HASH)
1286 return;
1287 ftrace_hash_clear(hash);
1288 kfree(hash->buckets);
1289 kfree(hash);
1290}
1291
1292static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1293{
1294 struct ftrace_hash *hash;
1295
1296 hash = container_of(rcu, struct ftrace_hash, rcu);
1297 free_ftrace_hash(hash);
1298}
1299
1300static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1301{
1302 if (!hash || hash == EMPTY_HASH)
1303 return;
1304 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1305}
1306
1307void ftrace_free_filter(struct ftrace_ops *ops)
1308{
1309 ftrace_ops_init(ops);
1310 free_ftrace_hash(ops->func_hash->filter_hash);
1311 free_ftrace_hash(ops->func_hash->notrace_hash);
1312}
1313
1314static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1315{
1316 struct ftrace_hash *hash;
1317 int size;
1318
1319 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1320 if (!hash)
1321 return NULL;
1322
1323 size = 1 << size_bits;
1324 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1325
1326 if (!hash->buckets) {
1327 kfree(hash);
1328 return NULL;
1329 }
1330
1331 hash->size_bits = size_bits;
1332
1333 return hash;
1334}
1335
1336static struct ftrace_hash *
1337alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1338{
1339 struct ftrace_func_entry *entry;
1340 struct ftrace_hash *new_hash;
1341 int size;
1342 int ret;
1343 int i;
1344
1345 new_hash = alloc_ftrace_hash(size_bits);
1346 if (!new_hash)
1347 return NULL;
1348
1349 /* Empty hash? */
1350 if (ftrace_hash_empty(hash))
1351 return new_hash;
1352
1353 size = 1 << hash->size_bits;
1354 for (i = 0; i < size; i++) {
1355 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1356 ret = add_hash_entry(new_hash, entry->ip);
1357 if (ret < 0)
1358 goto free_hash;
1359 }
1360 }
1361
1362 FTRACE_WARN_ON(new_hash->count != hash->count);
1363
1364 return new_hash;
1365
1366 free_hash:
1367 free_ftrace_hash(new_hash);
1368 return NULL;
1369}
1370
1371static void
1372ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1373static void
1374ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1375
1376static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1377 struct ftrace_hash *new_hash);
1378
1379static int
1380ftrace_hash_move(struct ftrace_ops *ops, int enable,
1381 struct ftrace_hash **dst, struct ftrace_hash *src)
1382{
1383 struct ftrace_func_entry *entry;
1384 struct hlist_node *tn;
1385 struct hlist_head *hhd;
1386 struct ftrace_hash *new_hash;
1387 int size = src->count;
1388 int bits = 0;
1389 int ret;
1390 int i;
1391
1392 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1393 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1394 return -EINVAL;
1395
1396 /*
1397 * If the new source is empty, just free dst and assign it
1398 * the empty_hash.
1399 */
1400 if (!src->count) {
1401 new_hash = EMPTY_HASH;
1402 goto update;
1403 }
1404
1405 /*
1406 * Make the hash size about 1/2 the # found
1407 */
1408 for (size /= 2; size; size >>= 1)
1409 bits++;
1410
1411 /* Don't allocate too much */
1412 if (bits > FTRACE_HASH_MAX_BITS)
1413 bits = FTRACE_HASH_MAX_BITS;
1414
1415 new_hash = alloc_ftrace_hash(bits);
1416 if (!new_hash)
1417 return -ENOMEM;
1418
1419 size = 1 << src->size_bits;
1420 for (i = 0; i < size; i++) {
1421 hhd = &src->buckets[i];
1422 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1423 remove_hash_entry(src, entry);
1424 __add_hash_entry(new_hash, entry);
1425 }
1426 }
1427
1428update:
1429 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1430 if (enable) {
1431 /* IPMODIFY should be updated only when filter_hash updating */
1432 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1433 if (ret < 0) {
1434 free_ftrace_hash(new_hash);
1435 return ret;
1436 }
1437 }
1438
1439 /*
1440 * Remove the current set, update the hash and add
1441 * them back.
1442 */
1443 ftrace_hash_rec_disable_modify(ops, enable);
1444
1445 rcu_assign_pointer(*dst, new_hash);
1446
1447 ftrace_hash_rec_enable_modify(ops, enable);
1448
1449 return 0;
1450}
1451
1452static bool hash_contains_ip(unsigned long ip,
1453 struct ftrace_ops_hash *hash)
1454{
1455 /*
1456 * The function record is a match if it exists in the filter
1457 * hash and not in the notrace hash. Note, an emty hash is
1458 * considered a match for the filter hash, but an empty
1459 * notrace hash is considered not in the notrace hash.
1460 */
1461 return (ftrace_hash_empty(hash->filter_hash) ||
1462 ftrace_lookup_ip(hash->filter_hash, ip)) &&
1463 (ftrace_hash_empty(hash->notrace_hash) ||
1464 !ftrace_lookup_ip(hash->notrace_hash, ip));
1465}
1466
1467/*
1468 * Test the hashes for this ops to see if we want to call
1469 * the ops->func or not.
1470 *
1471 * It's a match if the ip is in the ops->filter_hash or
1472 * the filter_hash does not exist or is empty,
1473 * AND
1474 * the ip is not in the ops->notrace_hash.
1475 *
1476 * This needs to be called with preemption disabled as
1477 * the hashes are freed with call_rcu_sched().
1478 */
1479static int
1480ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1481{
1482 struct ftrace_ops_hash hash;
1483 int ret;
1484
1485#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1486 /*
1487 * There's a small race when adding ops that the ftrace handler
1488 * that wants regs, may be called without them. We can not
1489 * allow that handler to be called if regs is NULL.
1490 */
1491 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1492 return 0;
1493#endif
1494
1495 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1496 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1497
1498 if (hash_contains_ip(ip, &hash))
1499 ret = 1;
1500 else
1501 ret = 0;
1502
1503 return ret;
1504}
1505
1506/*
1507 * This is a double for. Do not use 'break' to break out of the loop,
1508 * you must use a goto.
1509 */
1510#define do_for_each_ftrace_rec(pg, rec) \
1511 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1512 int _____i; \
1513 for (_____i = 0; _____i < pg->index; _____i++) { \
1514 rec = &pg->records[_____i];
1515
1516#define while_for_each_ftrace_rec() \
1517 } \
1518 }
1519
1520
1521static int ftrace_cmp_recs(const void *a, const void *b)
1522{
1523 const struct dyn_ftrace *key = a;
1524 const struct dyn_ftrace *rec = b;
1525
1526 if (key->flags < rec->ip)
1527 return -1;
1528 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1529 return 1;
1530 return 0;
1531}
1532
1533static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1534{
1535 struct ftrace_page *pg;
1536 struct dyn_ftrace *rec;
1537 struct dyn_ftrace key;
1538
1539 key.ip = start;
1540 key.flags = end; /* overload flags, as it is unsigned long */
1541
1542 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1543 if (end < pg->records[0].ip ||
1544 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1545 continue;
1546 rec = bsearch(&key, pg->records, pg->index,
1547 sizeof(struct dyn_ftrace),
1548 ftrace_cmp_recs);
1549 if (rec)
1550 return rec->ip;
1551 }
1552
1553 return 0;
1554}
1555
1556/**
1557 * ftrace_location - return true if the ip giving is a traced location
1558 * @ip: the instruction pointer to check
1559 *
1560 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1561 * That is, the instruction that is either a NOP or call to
1562 * the function tracer. It checks the ftrace internal tables to
1563 * determine if the address belongs or not.
1564 */
1565unsigned long ftrace_location(unsigned long ip)
1566{
1567 return ftrace_location_range(ip, ip);
1568}
1569
1570/**
1571 * ftrace_text_reserved - return true if range contains an ftrace location
1572 * @start: start of range to search
1573 * @end: end of range to search (inclusive). @end points to the last byte to check.
1574 *
1575 * Returns 1 if @start and @end contains a ftrace location.
1576 * That is, the instruction that is either a NOP or call to
1577 * the function tracer. It checks the ftrace internal tables to
1578 * determine if the address belongs or not.
1579 */
1580int ftrace_text_reserved(const void *start, const void *end)
1581{
1582 unsigned long ret;
1583
1584 ret = ftrace_location_range((unsigned long)start,
1585 (unsigned long)end);
1586
1587 return (int)!!ret;
1588}
1589
1590/* Test if ops registered to this rec needs regs */
1591static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1592{
1593 struct ftrace_ops *ops;
1594 bool keep_regs = false;
1595
1596 for (ops = ftrace_ops_list;
1597 ops != &ftrace_list_end; ops = ops->next) {
1598 /* pass rec in as regs to have non-NULL val */
1599 if (ftrace_ops_test(ops, rec->ip, rec)) {
1600 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1601 keep_regs = true;
1602 break;
1603 }
1604 }
1605 }
1606
1607 return keep_regs;
1608}
1609
1610static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1611 int filter_hash,
1612 bool inc)
1613{
1614 struct ftrace_hash *hash;
1615 struct ftrace_hash *other_hash;
1616 struct ftrace_page *pg;
1617 struct dyn_ftrace *rec;
1618 bool update = false;
1619 int count = 0;
1620 int all = 0;
1621
1622 /* Only update if the ops has been registered */
1623 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1624 return false;
1625
1626 /*
1627 * In the filter_hash case:
1628 * If the count is zero, we update all records.
1629 * Otherwise we just update the items in the hash.
1630 *
1631 * In the notrace_hash case:
1632 * We enable the update in the hash.
1633 * As disabling notrace means enabling the tracing,
1634 * and enabling notrace means disabling, the inc variable
1635 * gets inversed.
1636 */
1637 if (filter_hash) {
1638 hash = ops->func_hash->filter_hash;
1639 other_hash = ops->func_hash->notrace_hash;
1640 if (ftrace_hash_empty(hash))
1641 all = 1;
1642 } else {
1643 inc = !inc;
1644 hash = ops->func_hash->notrace_hash;
1645 other_hash = ops->func_hash->filter_hash;
1646 /*
1647 * If the notrace hash has no items,
1648 * then there's nothing to do.
1649 */
1650 if (ftrace_hash_empty(hash))
1651 return false;
1652 }
1653
1654 do_for_each_ftrace_rec(pg, rec) {
1655 int in_other_hash = 0;
1656 int in_hash = 0;
1657 int match = 0;
1658
1659 if (rec->flags & FTRACE_FL_DISABLED)
1660 continue;
1661
1662 if (all) {
1663 /*
1664 * Only the filter_hash affects all records.
1665 * Update if the record is not in the notrace hash.
1666 */
1667 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1668 match = 1;
1669 } else {
1670 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1671 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1672
1673 /*
1674 * If filter_hash is set, we want to match all functions
1675 * that are in the hash but not in the other hash.
1676 *
1677 * If filter_hash is not set, then we are decrementing.
1678 * That means we match anything that is in the hash
1679 * and also in the other_hash. That is, we need to turn
1680 * off functions in the other hash because they are disabled
1681 * by this hash.
1682 */
1683 if (filter_hash && in_hash && !in_other_hash)
1684 match = 1;
1685 else if (!filter_hash && in_hash &&
1686 (in_other_hash || ftrace_hash_empty(other_hash)))
1687 match = 1;
1688 }
1689 if (!match)
1690 continue;
1691
1692 if (inc) {
1693 rec->flags++;
1694 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1695 return false;
1696
1697 /*
1698 * If there's only a single callback registered to a
1699 * function, and the ops has a trampoline registered
1700 * for it, then we can call it directly.
1701 */
1702 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1703 rec->flags |= FTRACE_FL_TRAMP;
1704 else
1705 /*
1706 * If we are adding another function callback
1707 * to this function, and the previous had a
1708 * custom trampoline in use, then we need to go
1709 * back to the default trampoline.
1710 */
1711 rec->flags &= ~FTRACE_FL_TRAMP;
1712
1713 /*
1714 * If any ops wants regs saved for this function
1715 * then all ops will get saved regs.
1716 */
1717 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1718 rec->flags |= FTRACE_FL_REGS;
1719 } else {
1720 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1721 return false;
1722 rec->flags--;
1723
1724 /*
1725 * If the rec had REGS enabled and the ops that is
1726 * being removed had REGS set, then see if there is
1727 * still any ops for this record that wants regs.
1728 * If not, we can stop recording them.
1729 */
1730 if (ftrace_rec_count(rec) > 0 &&
1731 rec->flags & FTRACE_FL_REGS &&
1732 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1733 if (!test_rec_ops_needs_regs(rec))
1734 rec->flags &= ~FTRACE_FL_REGS;
1735 }
1736
1737 /*
1738 * If the rec had TRAMP enabled, then it needs to
1739 * be cleared. As TRAMP can only be enabled iff
1740 * there is only a single ops attached to it.
1741 * In otherwords, always disable it on decrementing.
1742 * In the future, we may set it if rec count is
1743 * decremented to one, and the ops that is left
1744 * has a trampoline.
1745 */
1746 rec->flags &= ~FTRACE_FL_TRAMP;
1747
1748 /*
1749 * flags will be cleared in ftrace_check_record()
1750 * if rec count is zero.
1751 */
1752 }
1753 count++;
1754
1755 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1756 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1757
1758 /* Shortcut, if we handled all records, we are done. */
1759 if (!all && count == hash->count)
1760 return update;
1761 } while_for_each_ftrace_rec();
1762
1763 return update;
1764}
1765
1766static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1767 int filter_hash)
1768{
1769 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1770}
1771
1772static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1773 int filter_hash)
1774{
1775 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1776}
1777
1778static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1779 int filter_hash, int inc)
1780{
1781 struct ftrace_ops *op;
1782
1783 __ftrace_hash_rec_update(ops, filter_hash, inc);
1784
1785 if (ops->func_hash != &global_ops.local_hash)
1786 return;
1787
1788 /*
1789 * If the ops shares the global_ops hash, then we need to update
1790 * all ops that are enabled and use this hash.
1791 */
1792 do_for_each_ftrace_op(op, ftrace_ops_list) {
1793 /* Already done */
1794 if (op == ops)
1795 continue;
1796 if (op->func_hash == &global_ops.local_hash)
1797 __ftrace_hash_rec_update(op, filter_hash, inc);
1798 } while_for_each_ftrace_op(op);
1799}
1800
1801static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1802 int filter_hash)
1803{
1804 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1805}
1806
1807static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1808 int filter_hash)
1809{
1810 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1811}
1812
1813/*
1814 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1815 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1816 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1817 * Note that old_hash and new_hash has below meanings
1818 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1819 * - If the hash is EMPTY_HASH, it hits nothing
1820 * - Anything else hits the recs which match the hash entries.
1821 */
1822static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1823 struct ftrace_hash *old_hash,
1824 struct ftrace_hash *new_hash)
1825{
1826 struct ftrace_page *pg;
1827 struct dyn_ftrace *rec, *end = NULL;
1828 int in_old, in_new;
1829
1830 /* Only update if the ops has been registered */
1831 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1832 return 0;
1833
1834 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1835 return 0;
1836
1837 /*
1838 * Since the IPMODIFY is a very address sensitive action, we do not
1839 * allow ftrace_ops to set all functions to new hash.
1840 */
1841 if (!new_hash || !old_hash)
1842 return -EINVAL;
1843
1844 /* Update rec->flags */
1845 do_for_each_ftrace_rec(pg, rec) {
1846 /* We need to update only differences of filter_hash */
1847 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1848 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1849 if (in_old == in_new)
1850 continue;
1851
1852 if (in_new) {
1853 /* New entries must ensure no others are using it */
1854 if (rec->flags & FTRACE_FL_IPMODIFY)
1855 goto rollback;
1856 rec->flags |= FTRACE_FL_IPMODIFY;
1857 } else /* Removed entry */
1858 rec->flags &= ~FTRACE_FL_IPMODIFY;
1859 } while_for_each_ftrace_rec();
1860
1861 return 0;
1862
1863rollback:
1864 end = rec;
1865
1866 /* Roll back what we did above */
1867 do_for_each_ftrace_rec(pg, rec) {
1868 if (rec == end)
1869 goto err_out;
1870
1871 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1872 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1873 if (in_old == in_new)
1874 continue;
1875
1876 if (in_new)
1877 rec->flags &= ~FTRACE_FL_IPMODIFY;
1878 else
1879 rec->flags |= FTRACE_FL_IPMODIFY;
1880 } while_for_each_ftrace_rec();
1881
1882err_out:
1883 return -EBUSY;
1884}
1885
1886static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1887{
1888 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1889
1890 if (ftrace_hash_empty(hash))
1891 hash = NULL;
1892
1893 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1894}
1895
1896/* Disabling always succeeds */
1897static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1898{
1899 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1900
1901 if (ftrace_hash_empty(hash))
1902 hash = NULL;
1903
1904 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1905}
1906
1907static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1908 struct ftrace_hash *new_hash)
1909{
1910 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1911
1912 if (ftrace_hash_empty(old_hash))
1913 old_hash = NULL;
1914
1915 if (ftrace_hash_empty(new_hash))
1916 new_hash = NULL;
1917
1918 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1919}
1920
1921static void print_ip_ins(const char *fmt, const unsigned char *p)
1922{
1923 int i;
1924
1925 printk(KERN_CONT "%s", fmt);
1926
1927 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1928 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1929}
1930
1931static struct ftrace_ops *
1932ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1933static struct ftrace_ops *
1934ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1935
1936enum ftrace_bug_type ftrace_bug_type;
1937const void *ftrace_expected;
1938
1939static void print_bug_type(void)
1940{
1941 switch (ftrace_bug_type) {
1942 case FTRACE_BUG_UNKNOWN:
1943 break;
1944 case FTRACE_BUG_INIT:
1945 pr_info("Initializing ftrace call sites\n");
1946 break;
1947 case FTRACE_BUG_NOP:
1948 pr_info("Setting ftrace call site to NOP\n");
1949 break;
1950 case FTRACE_BUG_CALL:
1951 pr_info("Setting ftrace call site to call ftrace function\n");
1952 break;
1953 case FTRACE_BUG_UPDATE:
1954 pr_info("Updating ftrace call site to call a different ftrace function\n");
1955 break;
1956 }
1957}
1958
1959/**
1960 * ftrace_bug - report and shutdown function tracer
1961 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1962 * @rec: The record that failed
1963 *
1964 * The arch code that enables or disables the function tracing
1965 * can call ftrace_bug() when it has detected a problem in
1966 * modifying the code. @failed should be one of either:
1967 * EFAULT - if the problem happens on reading the @ip address
1968 * EINVAL - if what is read at @ip is not what was expected
1969 * EPERM - if the problem happens on writting to the @ip address
1970 */
1971void ftrace_bug(int failed, struct dyn_ftrace *rec)
1972{
1973 unsigned long ip = rec ? rec->ip : 0;
1974
1975 switch (failed) {
1976 case -EFAULT:
1977 FTRACE_WARN_ON_ONCE(1);
1978 pr_info("ftrace faulted on modifying ");
1979 print_ip_sym(ip);
1980 break;
1981 case -EINVAL:
1982 FTRACE_WARN_ON_ONCE(1);
1983 pr_info("ftrace failed to modify ");
1984 print_ip_sym(ip);
1985 print_ip_ins(" actual: ", (unsigned char *)ip);
1986 pr_cont("\n");
1987 if (ftrace_expected) {
1988 print_ip_ins(" expected: ", ftrace_expected);
1989 pr_cont("\n");
1990 }
1991 break;
1992 case -EPERM:
1993 FTRACE_WARN_ON_ONCE(1);
1994 pr_info("ftrace faulted on writing ");
1995 print_ip_sym(ip);
1996 break;
1997 default:
1998 FTRACE_WARN_ON_ONCE(1);
1999 pr_info("ftrace faulted on unknown error ");
2000 print_ip_sym(ip);
2001 }
2002 print_bug_type();
2003 if (rec) {
2004 struct ftrace_ops *ops = NULL;
2005
2006 pr_info("ftrace record flags: %lx\n", rec->flags);
2007 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2008 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2009 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2010 ops = ftrace_find_tramp_ops_any(rec);
2011 if (ops) {
2012 do {
2013 pr_cont("\ttramp: %pS (%pS)",
2014 (void *)ops->trampoline,
2015 (void *)ops->func);
2016 ops = ftrace_find_tramp_ops_next(rec, ops);
2017 } while (ops);
2018 } else
2019 pr_cont("\ttramp: ERROR!");
2020
2021 }
2022 ip = ftrace_get_addr_curr(rec);
2023 pr_cont("\n expected tramp: %lx\n", ip);
2024 }
2025}
2026
2027static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2028{
2029 unsigned long flag = 0UL;
2030
2031 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2032
2033 if (rec->flags & FTRACE_FL_DISABLED)
2034 return FTRACE_UPDATE_IGNORE;
2035
2036 /*
2037 * If we are updating calls:
2038 *
2039 * If the record has a ref count, then we need to enable it
2040 * because someone is using it.
2041 *
2042 * Otherwise we make sure its disabled.
2043 *
2044 * If we are disabling calls, then disable all records that
2045 * are enabled.
2046 */
2047 if (enable && ftrace_rec_count(rec))
2048 flag = FTRACE_FL_ENABLED;
2049
2050 /*
2051 * If enabling and the REGS flag does not match the REGS_EN, or
2052 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2053 * this record. Set flags to fail the compare against ENABLED.
2054 */
2055 if (flag) {
2056 if (!(rec->flags & FTRACE_FL_REGS) !=
2057 !(rec->flags & FTRACE_FL_REGS_EN))
2058 flag |= FTRACE_FL_REGS;
2059
2060 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2061 !(rec->flags & FTRACE_FL_TRAMP_EN))
2062 flag |= FTRACE_FL_TRAMP;
2063 }
2064
2065 /* If the state of this record hasn't changed, then do nothing */
2066 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2067 return FTRACE_UPDATE_IGNORE;
2068
2069 if (flag) {
2070 /* Save off if rec is being enabled (for return value) */
2071 flag ^= rec->flags & FTRACE_FL_ENABLED;
2072
2073 if (update) {
2074 rec->flags |= FTRACE_FL_ENABLED;
2075 if (flag & FTRACE_FL_REGS) {
2076 if (rec->flags & FTRACE_FL_REGS)
2077 rec->flags |= FTRACE_FL_REGS_EN;
2078 else
2079 rec->flags &= ~FTRACE_FL_REGS_EN;
2080 }
2081 if (flag & FTRACE_FL_TRAMP) {
2082 if (rec->flags & FTRACE_FL_TRAMP)
2083 rec->flags |= FTRACE_FL_TRAMP_EN;
2084 else
2085 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2086 }
2087 }
2088
2089 /*
2090 * If this record is being updated from a nop, then
2091 * return UPDATE_MAKE_CALL.
2092 * Otherwise,
2093 * return UPDATE_MODIFY_CALL to tell the caller to convert
2094 * from the save regs, to a non-save regs function or
2095 * vice versa, or from a trampoline call.
2096 */
2097 if (flag & FTRACE_FL_ENABLED) {
2098 ftrace_bug_type = FTRACE_BUG_CALL;
2099 return FTRACE_UPDATE_MAKE_CALL;
2100 }
2101
2102 ftrace_bug_type = FTRACE_BUG_UPDATE;
2103 return FTRACE_UPDATE_MODIFY_CALL;
2104 }
2105
2106 if (update) {
2107 /* If there's no more users, clear all flags */
2108 if (!ftrace_rec_count(rec))
2109 rec->flags = 0;
2110 else
2111 /*
2112 * Just disable the record, but keep the ops TRAMP
2113 * and REGS states. The _EN flags must be disabled though.
2114 */
2115 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2116 FTRACE_FL_REGS_EN);
2117 }
2118
2119 ftrace_bug_type = FTRACE_BUG_NOP;
2120 return FTRACE_UPDATE_MAKE_NOP;
2121}
2122
2123/**
2124 * ftrace_update_record, set a record that now is tracing or not
2125 * @rec: the record to update
2126 * @enable: set to 1 if the record is tracing, zero to force disable
2127 *
2128 * The records that represent all functions that can be traced need
2129 * to be updated when tracing has been enabled.
2130 */
2131int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2132{
2133 return ftrace_check_record(rec, enable, 1);
2134}
2135
2136/**
2137 * ftrace_test_record, check if the record has been enabled or not
2138 * @rec: the record to test
2139 * @enable: set to 1 to check if enabled, 0 if it is disabled
2140 *
2141 * The arch code may need to test if a record is already set to
2142 * tracing to determine how to modify the function code that it
2143 * represents.
2144 */
2145int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2146{
2147 return ftrace_check_record(rec, enable, 0);
2148}
2149
2150static struct ftrace_ops *
2151ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2152{
2153 struct ftrace_ops *op;
2154 unsigned long ip = rec->ip;
2155
2156 do_for_each_ftrace_op(op, ftrace_ops_list) {
2157
2158 if (!op->trampoline)
2159 continue;
2160
2161 if (hash_contains_ip(ip, op->func_hash))
2162 return op;
2163 } while_for_each_ftrace_op(op);
2164
2165 return NULL;
2166}
2167
2168static struct ftrace_ops *
2169ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2170 struct ftrace_ops *op)
2171{
2172 unsigned long ip = rec->ip;
2173
2174 while_for_each_ftrace_op(op) {
2175
2176 if (!op->trampoline)
2177 continue;
2178
2179 if (hash_contains_ip(ip, op->func_hash))
2180 return op;
2181 }
2182
2183 return NULL;
2184}
2185
2186static struct ftrace_ops *
2187ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2188{
2189 struct ftrace_ops *op;
2190 unsigned long ip = rec->ip;
2191
2192 /*
2193 * Need to check removed ops first.
2194 * If they are being removed, and this rec has a tramp,
2195 * and this rec is in the ops list, then it would be the
2196 * one with the tramp.
2197 */
2198 if (removed_ops) {
2199 if (hash_contains_ip(ip, &removed_ops->old_hash))
2200 return removed_ops;
2201 }
2202
2203 /*
2204 * Need to find the current trampoline for a rec.
2205 * Now, a trampoline is only attached to a rec if there
2206 * was a single 'ops' attached to it. But this can be called
2207 * when we are adding another op to the rec or removing the
2208 * current one. Thus, if the op is being added, we can
2209 * ignore it because it hasn't attached itself to the rec
2210 * yet.
2211 *
2212 * If an ops is being modified (hooking to different functions)
2213 * then we don't care about the new functions that are being
2214 * added, just the old ones (that are probably being removed).
2215 *
2216 * If we are adding an ops to a function that already is using
2217 * a trampoline, it needs to be removed (trampolines are only
2218 * for single ops connected), then an ops that is not being
2219 * modified also needs to be checked.
2220 */
2221 do_for_each_ftrace_op(op, ftrace_ops_list) {
2222
2223 if (!op->trampoline)
2224 continue;
2225
2226 /*
2227 * If the ops is being added, it hasn't gotten to
2228 * the point to be removed from this tree yet.
2229 */
2230 if (op->flags & FTRACE_OPS_FL_ADDING)
2231 continue;
2232
2233
2234 /*
2235 * If the ops is being modified and is in the old
2236 * hash, then it is probably being removed from this
2237 * function.
2238 */
2239 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2240 hash_contains_ip(ip, &op->old_hash))
2241 return op;
2242 /*
2243 * If the ops is not being added or modified, and it's
2244 * in its normal filter hash, then this must be the one
2245 * we want!
2246 */
2247 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2248 hash_contains_ip(ip, op->func_hash))
2249 return op;
2250
2251 } while_for_each_ftrace_op(op);
2252
2253 return NULL;
2254}
2255
2256static struct ftrace_ops *
2257ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2258{
2259 struct ftrace_ops *op;
2260 unsigned long ip = rec->ip;
2261
2262 do_for_each_ftrace_op(op, ftrace_ops_list) {
2263 /* pass rec in as regs to have non-NULL val */
2264 if (hash_contains_ip(ip, op->func_hash))
2265 return op;
2266 } while_for_each_ftrace_op(op);
2267
2268 return NULL;
2269}
2270
2271/**
2272 * ftrace_get_addr_new - Get the call address to set to
2273 * @rec: The ftrace record descriptor
2274 *
2275 * If the record has the FTRACE_FL_REGS set, that means that it
2276 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2277 * is not not set, then it wants to convert to the normal callback.
2278 *
2279 * Returns the address of the trampoline to set to
2280 */
2281unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2282{
2283 struct ftrace_ops *ops;
2284
2285 /* Trampolines take precedence over regs */
2286 if (rec->flags & FTRACE_FL_TRAMP) {
2287 ops = ftrace_find_tramp_ops_new(rec);
2288 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2289 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2290 (void *)rec->ip, (void *)rec->ip, rec->flags);
2291 /* Ftrace is shutting down, return anything */
2292 return (unsigned long)FTRACE_ADDR;
2293 }
2294 return ops->trampoline;
2295 }
2296
2297 if (rec->flags & FTRACE_FL_REGS)
2298 return (unsigned long)FTRACE_REGS_ADDR;
2299 else
2300 return (unsigned long)FTRACE_ADDR;
2301}
2302
2303/**
2304 * ftrace_get_addr_curr - Get the call address that is already there
2305 * @rec: The ftrace record descriptor
2306 *
2307 * The FTRACE_FL_REGS_EN is set when the record already points to
2308 * a function that saves all the regs. Basically the '_EN' version
2309 * represents the current state of the function.
2310 *
2311 * Returns the address of the trampoline that is currently being called
2312 */
2313unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2314{
2315 struct ftrace_ops *ops;
2316
2317 /* Trampolines take precedence over regs */
2318 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2319 ops = ftrace_find_tramp_ops_curr(rec);
2320 if (FTRACE_WARN_ON(!ops)) {
2321 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2322 (void *)rec->ip, (void *)rec->ip);
2323 /* Ftrace is shutting down, return anything */
2324 return (unsigned long)FTRACE_ADDR;
2325 }
2326 return ops->trampoline;
2327 }
2328
2329 if (rec->flags & FTRACE_FL_REGS_EN)
2330 return (unsigned long)FTRACE_REGS_ADDR;
2331 else
2332 return (unsigned long)FTRACE_ADDR;
2333}
2334
2335static int
2336__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2337{
2338 unsigned long ftrace_old_addr;
2339 unsigned long ftrace_addr;
2340 int ret;
2341
2342 ftrace_addr = ftrace_get_addr_new(rec);
2343
2344 /* This needs to be done before we call ftrace_update_record */
2345 ftrace_old_addr = ftrace_get_addr_curr(rec);
2346
2347 ret = ftrace_update_record(rec, enable);
2348
2349 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2350
2351 switch (ret) {
2352 case FTRACE_UPDATE_IGNORE:
2353 return 0;
2354
2355 case FTRACE_UPDATE_MAKE_CALL:
2356 ftrace_bug_type = FTRACE_BUG_CALL;
2357 return ftrace_make_call(rec, ftrace_addr);
2358
2359 case FTRACE_UPDATE_MAKE_NOP:
2360 ftrace_bug_type = FTRACE_BUG_NOP;
2361 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2362
2363 case FTRACE_UPDATE_MODIFY_CALL:
2364 ftrace_bug_type = FTRACE_BUG_UPDATE;
2365 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2366 }
2367
2368 return -1; /* unknow ftrace bug */
2369}
2370
2371void __weak ftrace_replace_code(int enable)
2372{
2373 struct dyn_ftrace *rec;
2374 struct ftrace_page *pg;
2375 int failed;
2376
2377 if (unlikely(ftrace_disabled))
2378 return;
2379
2380 do_for_each_ftrace_rec(pg, rec) {
2381 failed = __ftrace_replace_code(rec, enable);
2382 if (failed) {
2383 ftrace_bug(failed, rec);
2384 /* Stop processing */
2385 return;
2386 }
2387 } while_for_each_ftrace_rec();
2388}
2389
2390struct ftrace_rec_iter {
2391 struct ftrace_page *pg;
2392 int index;
2393};
2394
2395/**
2396 * ftrace_rec_iter_start, start up iterating over traced functions
2397 *
2398 * Returns an iterator handle that is used to iterate over all
2399 * the records that represent address locations where functions
2400 * are traced.
2401 *
2402 * May return NULL if no records are available.
2403 */
2404struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2405{
2406 /*
2407 * We only use a single iterator.
2408 * Protected by the ftrace_lock mutex.
2409 */
2410 static struct ftrace_rec_iter ftrace_rec_iter;
2411 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2412
2413 iter->pg = ftrace_pages_start;
2414 iter->index = 0;
2415
2416 /* Could have empty pages */
2417 while (iter->pg && !iter->pg->index)
2418 iter->pg = iter->pg->next;
2419
2420 if (!iter->pg)
2421 return NULL;
2422
2423 return iter;
2424}
2425
2426/**
2427 * ftrace_rec_iter_next, get the next record to process.
2428 * @iter: The handle to the iterator.
2429 *
2430 * Returns the next iterator after the given iterator @iter.
2431 */
2432struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2433{
2434 iter->index++;
2435
2436 if (iter->index >= iter->pg->index) {
2437 iter->pg = iter->pg->next;
2438 iter->index = 0;
2439
2440 /* Could have empty pages */
2441 while (iter->pg && !iter->pg->index)
2442 iter->pg = iter->pg->next;
2443 }
2444
2445 if (!iter->pg)
2446 return NULL;
2447
2448 return iter;
2449}
2450
2451/**
2452 * ftrace_rec_iter_record, get the record at the iterator location
2453 * @iter: The current iterator location
2454 *
2455 * Returns the record that the current @iter is at.
2456 */
2457struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2458{
2459 return &iter->pg->records[iter->index];
2460}
2461
2462static int
2463ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2464{
2465 int ret;
2466
2467 if (unlikely(ftrace_disabled))
2468 return 0;
2469
2470 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2471 if (ret) {
2472 ftrace_bug_type = FTRACE_BUG_INIT;
2473 ftrace_bug(ret, rec);
2474 return 0;
2475 }
2476 return 1;
2477}
2478
2479/*
2480 * archs can override this function if they must do something
2481 * before the modifying code is performed.
2482 */
2483int __weak ftrace_arch_code_modify_prepare(void)
2484{
2485 return 0;
2486}
2487
2488/*
2489 * archs can override this function if they must do something
2490 * after the modifying code is performed.
2491 */
2492int __weak ftrace_arch_code_modify_post_process(void)
2493{
2494 return 0;
2495}
2496
2497void ftrace_modify_all_code(int command)
2498{
2499 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2500 int err = 0;
2501
2502 /*
2503 * If the ftrace_caller calls a ftrace_ops func directly,
2504 * we need to make sure that it only traces functions it
2505 * expects to trace. When doing the switch of functions,
2506 * we need to update to the ftrace_ops_list_func first
2507 * before the transition between old and new calls are set,
2508 * as the ftrace_ops_list_func will check the ops hashes
2509 * to make sure the ops are having the right functions
2510 * traced.
2511 */
2512 if (update) {
2513 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2514 if (FTRACE_WARN_ON(err))
2515 return;
2516 }
2517
2518 if (command & FTRACE_UPDATE_CALLS)
2519 ftrace_replace_code(1);
2520 else if (command & FTRACE_DISABLE_CALLS)
2521 ftrace_replace_code(0);
2522
2523 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2524 function_trace_op = set_function_trace_op;
2525 smp_wmb();
2526 /* If irqs are disabled, we are in stop machine */
2527 if (!irqs_disabled())
2528 smp_call_function(ftrace_sync_ipi, NULL, 1);
2529 err = ftrace_update_ftrace_func(ftrace_trace_function);
2530 if (FTRACE_WARN_ON(err))
2531 return;
2532 }
2533
2534 if (command & FTRACE_START_FUNC_RET)
2535 err = ftrace_enable_ftrace_graph_caller();
2536 else if (command & FTRACE_STOP_FUNC_RET)
2537 err = ftrace_disable_ftrace_graph_caller();
2538 FTRACE_WARN_ON(err);
2539}
2540
2541static int __ftrace_modify_code(void *data)
2542{
2543 int *command = data;
2544
2545 ftrace_modify_all_code(*command);
2546
2547 return 0;
2548}
2549
2550/**
2551 * ftrace_run_stop_machine, go back to the stop machine method
2552 * @command: The command to tell ftrace what to do
2553 *
2554 * If an arch needs to fall back to the stop machine method, the
2555 * it can call this function.
2556 */
2557void ftrace_run_stop_machine(int command)
2558{
2559 stop_machine(__ftrace_modify_code, &command, NULL);
2560}
2561
2562/**
2563 * arch_ftrace_update_code, modify the code to trace or not trace
2564 * @command: The command that needs to be done
2565 *
2566 * Archs can override this function if it does not need to
2567 * run stop_machine() to modify code.
2568 */
2569void __weak arch_ftrace_update_code(int command)
2570{
2571 ftrace_run_stop_machine(command);
2572}
2573
2574static void ftrace_run_update_code(int command)
2575{
2576 int ret;
2577
2578 ret = ftrace_arch_code_modify_prepare();
2579 FTRACE_WARN_ON(ret);
2580 if (ret)
2581 return;
2582
2583 /*
2584 * By default we use stop_machine() to modify the code.
2585 * But archs can do what ever they want as long as it
2586 * is safe. The stop_machine() is the safest, but also
2587 * produces the most overhead.
2588 */
2589 arch_ftrace_update_code(command);
2590
2591 ret = ftrace_arch_code_modify_post_process();
2592 FTRACE_WARN_ON(ret);
2593}
2594
2595static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2596 struct ftrace_ops_hash *old_hash)
2597{
2598 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2599 ops->old_hash.filter_hash = old_hash->filter_hash;
2600 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2601 ftrace_run_update_code(command);
2602 ops->old_hash.filter_hash = NULL;
2603 ops->old_hash.notrace_hash = NULL;
2604 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2605}
2606
2607static ftrace_func_t saved_ftrace_func;
2608static int ftrace_start_up;
2609
2610void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2611{
2612}
2613
2614static void per_cpu_ops_free(struct ftrace_ops *ops)
2615{
2616 free_percpu(ops->disabled);
2617}
2618
2619static void ftrace_startup_enable(int command)
2620{
2621 if (saved_ftrace_func != ftrace_trace_function) {
2622 saved_ftrace_func = ftrace_trace_function;
2623 command |= FTRACE_UPDATE_TRACE_FUNC;
2624 }
2625
2626 if (!command || !ftrace_enabled)
2627 return;
2628
2629 ftrace_run_update_code(command);
2630}
2631
2632static void ftrace_startup_all(int command)
2633{
2634 update_all_ops = true;
2635 ftrace_startup_enable(command);
2636 update_all_ops = false;
2637}
2638
2639static int ftrace_startup(struct ftrace_ops *ops, int command)
2640{
2641 int ret;
2642
2643 if (unlikely(ftrace_disabled))
2644 return -ENODEV;
2645
2646 ret = __register_ftrace_function(ops);
2647 if (ret)
2648 return ret;
2649
2650 ftrace_start_up++;
2651
2652 /*
2653 * Note that ftrace probes uses this to start up
2654 * and modify functions it will probe. But we still
2655 * set the ADDING flag for modification, as probes
2656 * do not have trampolines. If they add them in the
2657 * future, then the probes will need to distinguish
2658 * between adding and updating probes.
2659 */
2660 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2661
2662 ret = ftrace_hash_ipmodify_enable(ops);
2663 if (ret < 0) {
2664 /* Rollback registration process */
2665 __unregister_ftrace_function(ops);
2666 ftrace_start_up--;
2667 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2668 return ret;
2669 }
2670
2671 if (ftrace_hash_rec_enable(ops, 1))
2672 command |= FTRACE_UPDATE_CALLS;
2673
2674 ftrace_startup_enable(command);
2675
2676 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2677
2678 return 0;
2679}
2680
2681static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2682{
2683 int ret;
2684
2685 if (unlikely(ftrace_disabled))
2686 return -ENODEV;
2687
2688 ret = __unregister_ftrace_function(ops);
2689 if (ret)
2690 return ret;
2691
2692 ftrace_start_up--;
2693 /*
2694 * Just warn in case of unbalance, no need to kill ftrace, it's not
2695 * critical but the ftrace_call callers may be never nopped again after
2696 * further ftrace uses.
2697 */
2698 WARN_ON_ONCE(ftrace_start_up < 0);
2699
2700 /* Disabling ipmodify never fails */
2701 ftrace_hash_ipmodify_disable(ops);
2702
2703 if (ftrace_hash_rec_disable(ops, 1))
2704 command |= FTRACE_UPDATE_CALLS;
2705
2706 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2707
2708 if (saved_ftrace_func != ftrace_trace_function) {
2709 saved_ftrace_func = ftrace_trace_function;
2710 command |= FTRACE_UPDATE_TRACE_FUNC;
2711 }
2712
2713 if (!command || !ftrace_enabled) {
2714 /*
2715 * If these are per_cpu ops, they still need their
2716 * per_cpu field freed. Since, function tracing is
2717 * not currently active, we can just free them
2718 * without synchronizing all CPUs.
2719 */
2720 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2721 per_cpu_ops_free(ops);
2722 return 0;
2723 }
2724
2725 /*
2726 * If the ops uses a trampoline, then it needs to be
2727 * tested first on update.
2728 */
2729 ops->flags |= FTRACE_OPS_FL_REMOVING;
2730 removed_ops = ops;
2731
2732 /* The trampoline logic checks the old hashes */
2733 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2734 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2735
2736 ftrace_run_update_code(command);
2737
2738 /*
2739 * If there's no more ops registered with ftrace, run a
2740 * sanity check to make sure all rec flags are cleared.
2741 */
2742 if (ftrace_ops_list == &ftrace_list_end) {
2743 struct ftrace_page *pg;
2744 struct dyn_ftrace *rec;
2745
2746 do_for_each_ftrace_rec(pg, rec) {
2747 if (FTRACE_WARN_ON_ONCE(rec->flags))
2748 pr_warn(" %pS flags:%lx\n",
2749 (void *)rec->ip, rec->flags);
2750 } while_for_each_ftrace_rec();
2751 }
2752
2753 ops->old_hash.filter_hash = NULL;
2754 ops->old_hash.notrace_hash = NULL;
2755
2756 removed_ops = NULL;
2757 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2758
2759 /*
2760 * Dynamic ops may be freed, we must make sure that all
2761 * callers are done before leaving this function.
2762 * The same goes for freeing the per_cpu data of the per_cpu
2763 * ops.
2764 *
2765 * Again, normal synchronize_sched() is not good enough.
2766 * We need to do a hard force of sched synchronization.
2767 * This is because we use preempt_disable() to do RCU, but
2768 * the function tracers can be called where RCU is not watching
2769 * (like before user_exit()). We can not rely on the RCU
2770 * infrastructure to do the synchronization, thus we must do it
2771 * ourselves.
2772 */
2773 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2774 schedule_on_each_cpu(ftrace_sync);
2775
2776 arch_ftrace_trampoline_free(ops);
2777
2778 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2779 per_cpu_ops_free(ops);
2780 }
2781
2782 return 0;
2783}
2784
2785static void ftrace_startup_sysctl(void)
2786{
2787 int command;
2788
2789 if (unlikely(ftrace_disabled))
2790 return;
2791
2792 /* Force update next time */
2793 saved_ftrace_func = NULL;
2794 /* ftrace_start_up is true if we want ftrace running */
2795 if (ftrace_start_up) {
2796 command = FTRACE_UPDATE_CALLS;
2797 if (ftrace_graph_active)
2798 command |= FTRACE_START_FUNC_RET;
2799 ftrace_startup_enable(command);
2800 }
2801}
2802
2803static void ftrace_shutdown_sysctl(void)
2804{
2805 int command;
2806
2807 if (unlikely(ftrace_disabled))
2808 return;
2809
2810 /* ftrace_start_up is true if ftrace is running */
2811 if (ftrace_start_up) {
2812 command = FTRACE_DISABLE_CALLS;
2813 if (ftrace_graph_active)
2814 command |= FTRACE_STOP_FUNC_RET;
2815 ftrace_run_update_code(command);
2816 }
2817}
2818
2819static cycle_t ftrace_update_time;
2820unsigned long ftrace_update_tot_cnt;
2821
2822static inline int ops_traces_mod(struct ftrace_ops *ops)
2823{
2824 /*
2825 * Filter_hash being empty will default to trace module.
2826 * But notrace hash requires a test of individual module functions.
2827 */
2828 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2829 ftrace_hash_empty(ops->func_hash->notrace_hash);
2830}
2831
2832/*
2833 * Check if the current ops references the record.
2834 *
2835 * If the ops traces all functions, then it was already accounted for.
2836 * If the ops does not trace the current record function, skip it.
2837 * If the ops ignores the function via notrace filter, skip it.
2838 */
2839static inline bool
2840ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2841{
2842 /* If ops isn't enabled, ignore it */
2843 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2844 return 0;
2845
2846 /* If ops traces all then it includes this function */
2847 if (ops_traces_mod(ops))
2848 return 1;
2849
2850 /* The function must be in the filter */
2851 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2852 !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2853 return 0;
2854
2855 /* If in notrace hash, we ignore it too */
2856 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2857 return 0;
2858
2859 return 1;
2860}
2861
2862static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2863{
2864 struct ftrace_page *pg;
2865 struct dyn_ftrace *p;
2866 cycle_t start, stop;
2867 unsigned long update_cnt = 0;
2868 unsigned long rec_flags = 0;
2869 int i;
2870
2871 start = ftrace_now(raw_smp_processor_id());
2872
2873 /*
2874 * When a module is loaded, this function is called to convert
2875 * the calls to mcount in its text to nops, and also to create
2876 * an entry in the ftrace data. Now, if ftrace is activated
2877 * after this call, but before the module sets its text to
2878 * read-only, the modification of enabling ftrace can fail if
2879 * the read-only is done while ftrace is converting the calls.
2880 * To prevent this, the module's records are set as disabled
2881 * and will be enabled after the call to set the module's text
2882 * to read-only.
2883 */
2884 if (mod)
2885 rec_flags |= FTRACE_FL_DISABLED;
2886
2887 for (pg = new_pgs; pg; pg = pg->next) {
2888
2889 for (i = 0; i < pg->index; i++) {
2890
2891 /* If something went wrong, bail without enabling anything */
2892 if (unlikely(ftrace_disabled))
2893 return -1;
2894
2895 p = &pg->records[i];
2896 p->flags = rec_flags;
2897
2898 /*
2899 * Do the initial record conversion from mcount jump
2900 * to the NOP instructions.
2901 */
2902 if (!ftrace_code_disable(mod, p))
2903 break;
2904
2905 update_cnt++;
2906 }
2907 }
2908
2909 stop = ftrace_now(raw_smp_processor_id());
2910 ftrace_update_time = stop - start;
2911 ftrace_update_tot_cnt += update_cnt;
2912
2913 return 0;
2914}
2915
2916static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2917{
2918 int order;
2919 int cnt;
2920
2921 if (WARN_ON(!count))
2922 return -EINVAL;
2923
2924 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2925
2926 /*
2927 * We want to fill as much as possible. No more than a page
2928 * may be empty.
2929 */
2930 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2931 order--;
2932
2933 again:
2934 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2935
2936 if (!pg->records) {
2937 /* if we can't allocate this size, try something smaller */
2938 if (!order)
2939 return -ENOMEM;
2940 order >>= 1;
2941 goto again;
2942 }
2943
2944 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2945 pg->size = cnt;
2946
2947 if (cnt > count)
2948 cnt = count;
2949
2950 return cnt;
2951}
2952
2953static struct ftrace_page *
2954ftrace_allocate_pages(unsigned long num_to_init)
2955{
2956 struct ftrace_page *start_pg;
2957 struct ftrace_page *pg;
2958 int order;
2959 int cnt;
2960
2961 if (!num_to_init)
2962 return 0;
2963
2964 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2965 if (!pg)
2966 return NULL;
2967
2968 /*
2969 * Try to allocate as much as possible in one continues
2970 * location that fills in all of the space. We want to
2971 * waste as little space as possible.
2972 */
2973 for (;;) {
2974 cnt = ftrace_allocate_records(pg, num_to_init);
2975 if (cnt < 0)
2976 goto free_pages;
2977
2978 num_to_init -= cnt;
2979 if (!num_to_init)
2980 break;
2981
2982 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2983 if (!pg->next)
2984 goto free_pages;
2985
2986 pg = pg->next;
2987 }
2988
2989 return start_pg;
2990
2991 free_pages:
2992 pg = start_pg;
2993 while (pg) {
2994 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2995 free_pages((unsigned long)pg->records, order);
2996 start_pg = pg->next;
2997 kfree(pg);
2998 pg = start_pg;
2999 }
3000 pr_info("ftrace: FAILED to allocate memory for functions\n");
3001 return NULL;
3002}
3003
3004#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3005
3006struct ftrace_iterator {
3007 loff_t pos;
3008 loff_t func_pos;
3009 struct ftrace_page *pg;
3010 struct dyn_ftrace *func;
3011 struct ftrace_func_probe *probe;
3012 struct trace_parser parser;
3013 struct ftrace_hash *hash;
3014 struct ftrace_ops *ops;
3015 int hidx;
3016 int idx;
3017 unsigned flags;
3018};
3019
3020static void *
3021t_hash_next(struct seq_file *m, loff_t *pos)
3022{
3023 struct ftrace_iterator *iter = m->private;
3024 struct hlist_node *hnd = NULL;
3025 struct hlist_head *hhd;
3026
3027 (*pos)++;
3028 iter->pos = *pos;
3029
3030 if (iter->probe)
3031 hnd = &iter->probe->node;
3032 retry:
3033 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3034 return NULL;
3035
3036 hhd = &ftrace_func_hash[iter->hidx];
3037
3038 if (hlist_empty(hhd)) {
3039 iter->hidx++;
3040 hnd = NULL;
3041 goto retry;
3042 }
3043
3044 if (!hnd)
3045 hnd = hhd->first;
3046 else {
3047 hnd = hnd->next;
3048 if (!hnd) {
3049 iter->hidx++;
3050 goto retry;
3051 }
3052 }
3053
3054 if (WARN_ON_ONCE(!hnd))
3055 return NULL;
3056
3057 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3058
3059 return iter;
3060}
3061
3062static void *t_hash_start(struct seq_file *m, loff_t *pos)
3063{
3064 struct ftrace_iterator *iter = m->private;
3065 void *p = NULL;
3066 loff_t l;
3067
3068 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3069 return NULL;
3070
3071 if (iter->func_pos > *pos)
3072 return NULL;
3073
3074 iter->hidx = 0;
3075 for (l = 0; l <= (*pos - iter->func_pos); ) {
3076 p = t_hash_next(m, &l);
3077 if (!p)
3078 break;
3079 }
3080 if (!p)
3081 return NULL;
3082
3083 /* Only set this if we have an item */
3084 iter->flags |= FTRACE_ITER_HASH;
3085
3086 return iter;
3087}
3088
3089static int
3090t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3091{
3092 struct ftrace_func_probe *rec;
3093
3094 rec = iter->probe;
3095 if (WARN_ON_ONCE(!rec))
3096 return -EIO;
3097
3098 if (rec->ops->print)
3099 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3100
3101 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3102
3103 if (rec->data)
3104 seq_printf(m, ":%p", rec->data);
3105 seq_putc(m, '\n');
3106
3107 return 0;
3108}
3109
3110static void *
3111t_next(struct seq_file *m, void *v, loff_t *pos)
3112{
3113 struct ftrace_iterator *iter = m->private;
3114 struct ftrace_ops *ops = iter->ops;
3115 struct dyn_ftrace *rec = NULL;
3116
3117 if (unlikely(ftrace_disabled))
3118 return NULL;
3119
3120 if (iter->flags & FTRACE_ITER_HASH)
3121 return t_hash_next(m, pos);
3122
3123 (*pos)++;
3124 iter->pos = iter->func_pos = *pos;
3125
3126 if (iter->flags & FTRACE_ITER_PRINTALL)
3127 return t_hash_start(m, pos);
3128
3129 retry:
3130 if (iter->idx >= iter->pg->index) {
3131 if (iter->pg->next) {
3132 iter->pg = iter->pg->next;
3133 iter->idx = 0;
3134 goto retry;
3135 }
3136 } else {
3137 rec = &iter->pg->records[iter->idx++];
3138 if (((iter->flags & FTRACE_ITER_FILTER) &&
3139 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3140
3141 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3142 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3143
3144 ((iter->flags & FTRACE_ITER_ENABLED) &&
3145 !(rec->flags & FTRACE_FL_ENABLED))) {
3146
3147 rec = NULL;
3148 goto retry;
3149 }
3150 }
3151
3152 if (!rec)
3153 return t_hash_start(m, pos);
3154
3155 iter->func = rec;
3156
3157 return iter;
3158}
3159
3160static void reset_iter_read(struct ftrace_iterator *iter)
3161{
3162 iter->pos = 0;
3163 iter->func_pos = 0;
3164 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3165}
3166
3167static void *t_start(struct seq_file *m, loff_t *pos)
3168{
3169 struct ftrace_iterator *iter = m->private;
3170 struct ftrace_ops *ops = iter->ops;
3171 void *p = NULL;
3172 loff_t l;
3173
3174 mutex_lock(&ftrace_lock);
3175
3176 if (unlikely(ftrace_disabled))
3177 return NULL;
3178
3179 /*
3180 * If an lseek was done, then reset and start from beginning.
3181 */
3182 if (*pos < iter->pos)
3183 reset_iter_read(iter);
3184
3185 /*
3186 * For set_ftrace_filter reading, if we have the filter
3187 * off, we can short cut and just print out that all
3188 * functions are enabled.
3189 */
3190 if ((iter->flags & FTRACE_ITER_FILTER &&
3191 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3192 (iter->flags & FTRACE_ITER_NOTRACE &&
3193 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3194 if (*pos > 0)
3195 return t_hash_start(m, pos);
3196 iter->flags |= FTRACE_ITER_PRINTALL;
3197 /* reset in case of seek/pread */
3198 iter->flags &= ~FTRACE_ITER_HASH;
3199 return iter;
3200 }
3201
3202 if (iter->flags & FTRACE_ITER_HASH)
3203 return t_hash_start(m, pos);
3204
3205 /*
3206 * Unfortunately, we need to restart at ftrace_pages_start
3207 * every time we let go of the ftrace_mutex. This is because
3208 * those pointers can change without the lock.
3209 */
3210 iter->pg = ftrace_pages_start;
3211 iter->idx = 0;
3212 for (l = 0; l <= *pos; ) {
3213 p = t_next(m, p, &l);
3214 if (!p)
3215 break;
3216 }
3217
3218 if (!p)
3219 return t_hash_start(m, pos);
3220
3221 return iter;
3222}
3223
3224static void t_stop(struct seq_file *m, void *p)
3225{
3226 mutex_unlock(&ftrace_lock);
3227}
3228
3229void * __weak
3230arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3231{
3232 return NULL;
3233}
3234
3235static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3236 struct dyn_ftrace *rec)
3237{
3238 void *ptr;
3239
3240 ptr = arch_ftrace_trampoline_func(ops, rec);
3241 if (ptr)
3242 seq_printf(m, " ->%pS", ptr);
3243}
3244
3245static int t_show(struct seq_file *m, void *v)
3246{
3247 struct ftrace_iterator *iter = m->private;
3248 struct dyn_ftrace *rec;
3249
3250 if (iter->flags & FTRACE_ITER_HASH)
3251 return t_hash_show(m, iter);
3252
3253 if (iter->flags & FTRACE_ITER_PRINTALL) {
3254 if (iter->flags & FTRACE_ITER_NOTRACE)
3255 seq_puts(m, "#### no functions disabled ####\n");
3256 else
3257 seq_puts(m, "#### all functions enabled ####\n");
3258 return 0;
3259 }
3260
3261 rec = iter->func;
3262
3263 if (!rec)
3264 return 0;
3265
3266 seq_printf(m, "%ps", (void *)rec->ip);
3267 if (iter->flags & FTRACE_ITER_ENABLED) {
3268 struct ftrace_ops *ops;
3269
3270 seq_printf(m, " (%ld)%s%s",
3271 ftrace_rec_count(rec),
3272 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3273 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3274 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3275 ops = ftrace_find_tramp_ops_any(rec);
3276 if (ops) {
3277 do {
3278 seq_printf(m, "\ttramp: %pS (%pS)",
3279 (void *)ops->trampoline,
3280 (void *)ops->func);
3281 add_trampoline_func(m, ops, rec);
3282 ops = ftrace_find_tramp_ops_next(rec, ops);
3283 } while (ops);
3284 } else
3285 seq_puts(m, "\ttramp: ERROR!");
3286 } else {
3287 add_trampoline_func(m, NULL, rec);
3288 }
3289 }
3290
3291 seq_putc(m, '\n');
3292
3293 return 0;
3294}
3295
3296static const struct seq_operations show_ftrace_seq_ops = {
3297 .start = t_start,
3298 .next = t_next,
3299 .stop = t_stop,
3300 .show = t_show,
3301};
3302
3303static int
3304ftrace_avail_open(struct inode *inode, struct file *file)
3305{
3306 struct ftrace_iterator *iter;
3307
3308 if (unlikely(ftrace_disabled))
3309 return -ENODEV;
3310
3311 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3312 if (iter) {
3313 iter->pg = ftrace_pages_start;
3314 iter->ops = &global_ops;
3315 }
3316
3317 return iter ? 0 : -ENOMEM;
3318}
3319
3320static int
3321ftrace_enabled_open(struct inode *inode, struct file *file)
3322{
3323 struct ftrace_iterator *iter;
3324
3325 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3326 if (iter) {
3327 iter->pg = ftrace_pages_start;
3328 iter->flags = FTRACE_ITER_ENABLED;
3329 iter->ops = &global_ops;
3330 }
3331
3332 return iter ? 0 : -ENOMEM;
3333}
3334
3335/**
3336 * ftrace_regex_open - initialize function tracer filter files
3337 * @ops: The ftrace_ops that hold the hash filters
3338 * @flag: The type of filter to process
3339 * @inode: The inode, usually passed in to your open routine
3340 * @file: The file, usually passed in to your open routine
3341 *
3342 * ftrace_regex_open() initializes the filter files for the
3343 * @ops. Depending on @flag it may process the filter hash or
3344 * the notrace hash of @ops. With this called from the open
3345 * routine, you can use ftrace_filter_write() for the write
3346 * routine if @flag has FTRACE_ITER_FILTER set, or
3347 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3348 * tracing_lseek() should be used as the lseek routine, and
3349 * release must call ftrace_regex_release().
3350 */
3351int
3352ftrace_regex_open(struct ftrace_ops *ops, int flag,
3353 struct inode *inode, struct file *file)
3354{
3355 struct ftrace_iterator *iter;
3356 struct ftrace_hash *hash;
3357 int ret = 0;
3358
3359 ftrace_ops_init(ops);
3360
3361 if (unlikely(ftrace_disabled))
3362 return -ENODEV;
3363
3364 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3365 if (!iter)
3366 return -ENOMEM;
3367
3368 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3369 kfree(iter);
3370 return -ENOMEM;
3371 }
3372
3373 iter->ops = ops;
3374 iter->flags = flag;
3375
3376 mutex_lock(&ops->func_hash->regex_lock);
3377
3378 if (flag & FTRACE_ITER_NOTRACE)
3379 hash = ops->func_hash->notrace_hash;
3380 else
3381 hash = ops->func_hash->filter_hash;
3382
3383 if (file->f_mode & FMODE_WRITE) {
3384 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3385
3386 if (file->f_flags & O_TRUNC)
3387 iter->hash = alloc_ftrace_hash(size_bits);
3388 else
3389 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3390
3391 if (!iter->hash) {
3392 trace_parser_put(&iter->parser);
3393 kfree(iter);
3394 ret = -ENOMEM;
3395 goto out_unlock;
3396 }
3397 }
3398
3399 if (file->f_mode & FMODE_READ) {
3400 iter->pg = ftrace_pages_start;
3401
3402 ret = seq_open(file, &show_ftrace_seq_ops);
3403 if (!ret) {
3404 struct seq_file *m = file->private_data;
3405 m->private = iter;
3406 } else {
3407 /* Failed */
3408 free_ftrace_hash(iter->hash);
3409 trace_parser_put(&iter->parser);
3410 kfree(iter);
3411 }
3412 } else
3413 file->private_data = iter;
3414
3415 out_unlock:
3416 mutex_unlock(&ops->func_hash->regex_lock);
3417
3418 return ret;
3419}
3420
3421static int
3422ftrace_filter_open(struct inode *inode, struct file *file)
3423{
3424 struct ftrace_ops *ops = inode->i_private;
3425
3426 return ftrace_regex_open(ops,
3427 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3428 inode, file);
3429}
3430
3431static int
3432ftrace_notrace_open(struct inode *inode, struct file *file)
3433{
3434 struct ftrace_ops *ops = inode->i_private;
3435
3436 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3437 inode, file);
3438}
3439
3440/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3441struct ftrace_glob {
3442 char *search;
3443 unsigned len;
3444 int type;
3445};
3446
3447static int ftrace_match(char *str, struct ftrace_glob *g)
3448{
3449 int matched = 0;
3450 int slen;
3451
3452 switch (g->type) {
3453 case MATCH_FULL:
3454 if (strcmp(str, g->search) == 0)
3455 matched = 1;
3456 break;
3457 case MATCH_FRONT_ONLY:
3458 if (strncmp(str, g->search, g->len) == 0)
3459 matched = 1;
3460 break;
3461 case MATCH_MIDDLE_ONLY:
3462 if (strstr(str, g->search))
3463 matched = 1;
3464 break;
3465 case MATCH_END_ONLY:
3466 slen = strlen(str);
3467 if (slen >= g->len &&
3468 memcmp(str + slen - g->len, g->search, g->len) == 0)
3469 matched = 1;
3470 break;
3471 }
3472
3473 return matched;
3474}
3475
3476static int
3477enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3478{
3479 struct ftrace_func_entry *entry;
3480 int ret = 0;
3481
3482 entry = ftrace_lookup_ip(hash, rec->ip);
3483 if (clear_filter) {
3484 /* Do nothing if it doesn't exist */
3485 if (!entry)
3486 return 0;
3487
3488 free_hash_entry(hash, entry);
3489 } else {
3490 /* Do nothing if it exists */
3491 if (entry)
3492 return 0;
3493
3494 ret = add_hash_entry(hash, rec->ip);
3495 }
3496 return ret;
3497}
3498
3499static int
3500ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3501 struct ftrace_glob *mod_g, int exclude_mod)
3502{
3503 char str[KSYM_SYMBOL_LEN];
3504 char *modname;
3505
3506 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3507
3508 if (mod_g) {
3509 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3510
3511 /* blank module name to match all modules */
3512 if (!mod_g->len) {
3513 /* blank module globbing: modname xor exclude_mod */
3514 if ((!exclude_mod) != (!modname))
3515 goto func_match;
3516 return 0;
3517 }
3518
3519 /* not matching the module */
3520 if (!modname || !mod_matches) {
3521 if (exclude_mod)
3522 goto func_match;
3523 else
3524 return 0;
3525 }
3526
3527 if (mod_matches && exclude_mod)
3528 return 0;
3529
3530func_match:
3531 /* blank search means to match all funcs in the mod */
3532 if (!func_g->len)
3533 return 1;
3534 }
3535
3536 return ftrace_match(str, func_g);
3537}
3538
3539static int
3540match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3541{
3542 struct ftrace_page *pg;
3543 struct dyn_ftrace *rec;
3544 struct ftrace_glob func_g = { .type = MATCH_FULL };
3545 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3546 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3547 int exclude_mod = 0;
3548 int found = 0;
3549 int ret;
3550 int clear_filter;
3551
3552 if (func) {
3553 func_g.type = filter_parse_regex(func, len, &func_g.search,
3554 &clear_filter);
3555 func_g.len = strlen(func_g.search);
3556 }
3557
3558 if (mod) {
3559 mod_g.type = filter_parse_regex(mod, strlen(mod),
3560 &mod_g.search, &exclude_mod);
3561 mod_g.len = strlen(mod_g.search);
3562 }
3563
3564 mutex_lock(&ftrace_lock);
3565
3566 if (unlikely(ftrace_disabled))
3567 goto out_unlock;
3568
3569 do_for_each_ftrace_rec(pg, rec) {
3570 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3571 ret = enter_record(hash, rec, clear_filter);
3572 if (ret < 0) {
3573 found = ret;
3574 goto out_unlock;
3575 }
3576 found = 1;
3577 }
3578 } while_for_each_ftrace_rec();
3579 out_unlock:
3580 mutex_unlock(&ftrace_lock);
3581
3582 return found;
3583}
3584
3585static int
3586ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3587{
3588 return match_records(hash, buff, len, NULL);
3589}
3590
3591
3592/*
3593 * We register the module command as a template to show others how
3594 * to register the a command as well.
3595 */
3596
3597static int
3598ftrace_mod_callback(struct ftrace_hash *hash,
3599 char *func, char *cmd, char *module, int enable)
3600{
3601 int ret;
3602
3603 /*
3604 * cmd == 'mod' because we only registered this func
3605 * for the 'mod' ftrace_func_command.
3606 * But if you register one func with multiple commands,
3607 * you can tell which command was used by the cmd
3608 * parameter.
3609 */
3610 ret = match_records(hash, func, strlen(func), module);
3611 if (!ret)
3612 return -EINVAL;
3613 if (ret < 0)
3614 return ret;
3615 return 0;
3616}
3617
3618static struct ftrace_func_command ftrace_mod_cmd = {
3619 .name = "mod",
3620 .func = ftrace_mod_callback,
3621};
3622
3623static int __init ftrace_mod_cmd_init(void)
3624{
3625 return register_ftrace_command(&ftrace_mod_cmd);
3626}
3627core_initcall(ftrace_mod_cmd_init);
3628
3629static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3630 struct ftrace_ops *op, struct pt_regs *pt_regs)
3631{
3632 struct ftrace_func_probe *entry;
3633 struct hlist_head *hhd;
3634 unsigned long key;
3635
3636 key = hash_long(ip, FTRACE_HASH_BITS);
3637
3638 hhd = &ftrace_func_hash[key];
3639
3640 if (hlist_empty(hhd))
3641 return;
3642
3643 /*
3644 * Disable preemption for these calls to prevent a RCU grace
3645 * period. This syncs the hash iteration and freeing of items
3646 * on the hash. rcu_read_lock is too dangerous here.
3647 */
3648 preempt_disable_notrace();
3649 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3650 if (entry->ip == ip)
3651 entry->ops->func(ip, parent_ip, &entry->data);
3652 }
3653 preempt_enable_notrace();
3654}
3655
3656static struct ftrace_ops trace_probe_ops __read_mostly =
3657{
3658 .func = function_trace_probe_call,
3659 .flags = FTRACE_OPS_FL_INITIALIZED,
3660 INIT_OPS_HASH(trace_probe_ops)
3661};
3662
3663static int ftrace_probe_registered;
3664
3665static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3666{
3667 int ret;
3668 int i;
3669
3670 if (ftrace_probe_registered) {
3671 /* still need to update the function call sites */
3672 if (ftrace_enabled)
3673 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3674 old_hash);
3675 return;
3676 }
3677
3678 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3679 struct hlist_head *hhd = &ftrace_func_hash[i];
3680 if (hhd->first)
3681 break;
3682 }
3683 /* Nothing registered? */
3684 if (i == FTRACE_FUNC_HASHSIZE)
3685 return;
3686
3687 ret = ftrace_startup(&trace_probe_ops, 0);
3688
3689 ftrace_probe_registered = 1;
3690}
3691
3692static void __disable_ftrace_function_probe(void)
3693{
3694 int i;
3695
3696 if (!ftrace_probe_registered)
3697 return;
3698
3699 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3700 struct hlist_head *hhd = &ftrace_func_hash[i];
3701 if (hhd->first)
3702 return;
3703 }
3704
3705 /* no more funcs left */
3706 ftrace_shutdown(&trace_probe_ops, 0);
3707
3708 ftrace_probe_registered = 0;
3709}
3710
3711
3712static void ftrace_free_entry(struct ftrace_func_probe *entry)
3713{
3714 if (entry->ops->free)
3715 entry->ops->free(entry->ops, entry->ip, &entry->data);
3716 kfree(entry);
3717}
3718
3719int
3720register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3721 void *data)
3722{
3723 struct ftrace_ops_hash old_hash_ops;
3724 struct ftrace_func_probe *entry;
3725 struct ftrace_glob func_g;
3726 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3727 struct ftrace_hash *old_hash = *orig_hash;
3728 struct ftrace_hash *hash;
3729 struct ftrace_page *pg;
3730 struct dyn_ftrace *rec;
3731 int not;
3732 unsigned long key;
3733 int count = 0;
3734 int ret;
3735
3736 func_g.type = filter_parse_regex(glob, strlen(glob),
3737 &func_g.search, ¬);
3738 func_g.len = strlen(func_g.search);
3739
3740 /* we do not support '!' for function probes */
3741 if (WARN_ON(not))
3742 return -EINVAL;
3743
3744 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3745
3746 old_hash_ops.filter_hash = old_hash;
3747 /* Probes only have filters */
3748 old_hash_ops.notrace_hash = NULL;
3749
3750 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3751 if (!hash) {
3752 count = -ENOMEM;
3753 goto out;
3754 }
3755
3756 if (unlikely(ftrace_disabled)) {
3757 count = -ENODEV;
3758 goto out;
3759 }
3760
3761 mutex_lock(&ftrace_lock);
3762
3763 do_for_each_ftrace_rec(pg, rec) {
3764
3765 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3766 continue;
3767
3768 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3769 if (!entry) {
3770 /* If we did not process any, then return error */
3771 if (!count)
3772 count = -ENOMEM;
3773 goto out_unlock;
3774 }
3775
3776 count++;
3777
3778 entry->data = data;
3779
3780 /*
3781 * The caller might want to do something special
3782 * for each function we find. We call the callback
3783 * to give the caller an opportunity to do so.
3784 */
3785 if (ops->init) {
3786 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3787 /* caller does not like this func */
3788 kfree(entry);
3789 continue;
3790 }
3791 }
3792
3793 ret = enter_record(hash, rec, 0);
3794 if (ret < 0) {
3795 kfree(entry);
3796 count = ret;
3797 goto out_unlock;
3798 }
3799
3800 entry->ops = ops;
3801 entry->ip = rec->ip;
3802
3803 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3804 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3805
3806 } while_for_each_ftrace_rec();
3807
3808 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3809
3810 __enable_ftrace_function_probe(&old_hash_ops);
3811
3812 if (!ret)
3813 free_ftrace_hash_rcu(old_hash);
3814 else
3815 count = ret;
3816
3817 out_unlock:
3818 mutex_unlock(&ftrace_lock);
3819 out:
3820 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3821 free_ftrace_hash(hash);
3822
3823 return count;
3824}
3825
3826enum {
3827 PROBE_TEST_FUNC = 1,
3828 PROBE_TEST_DATA = 2
3829};
3830
3831static void
3832__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3833 void *data, int flags)
3834{
3835 struct ftrace_func_entry *rec_entry;
3836 struct ftrace_func_probe *entry;
3837 struct ftrace_func_probe *p;
3838 struct ftrace_glob func_g;
3839 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3840 struct ftrace_hash *old_hash = *orig_hash;
3841 struct list_head free_list;
3842 struct ftrace_hash *hash;
3843 struct hlist_node *tmp;
3844 char str[KSYM_SYMBOL_LEN];
3845 int i, ret;
3846
3847 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3848 func_g.search = NULL;
3849 else if (glob) {
3850 int not;
3851
3852 func_g.type = filter_parse_regex(glob, strlen(glob),
3853 &func_g.search, ¬);
3854 func_g.len = strlen(func_g.search);
3855 func_g.search = glob;
3856
3857 /* we do not support '!' for function probes */
3858 if (WARN_ON(not))
3859 return;
3860 }
3861
3862 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3863
3864 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3865 if (!hash)
3866 /* Hmm, should report this somehow */
3867 goto out_unlock;
3868
3869 INIT_LIST_HEAD(&free_list);
3870
3871 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3872 struct hlist_head *hhd = &ftrace_func_hash[i];
3873
3874 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3875
3876 /* break up if statements for readability */
3877 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3878 continue;
3879
3880 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3881 continue;
3882
3883 /* do this last, since it is the most expensive */
3884 if (func_g.search) {
3885 kallsyms_lookup(entry->ip, NULL, NULL,
3886 NULL, str);
3887 if (!ftrace_match(str, &func_g))
3888 continue;
3889 }
3890
3891 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3892 /* It is possible more than one entry had this ip */
3893 if (rec_entry)
3894 free_hash_entry(hash, rec_entry);
3895
3896 hlist_del_rcu(&entry->node);
3897 list_add(&entry->free_list, &free_list);
3898 }
3899 }
3900 mutex_lock(&ftrace_lock);
3901 __disable_ftrace_function_probe();
3902 /*
3903 * Remove after the disable is called. Otherwise, if the last
3904 * probe is removed, a null hash means *all enabled*.
3905 */
3906 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3907 synchronize_sched();
3908 if (!ret)
3909 free_ftrace_hash_rcu(old_hash);
3910
3911 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3912 list_del(&entry->free_list);
3913 ftrace_free_entry(entry);
3914 }
3915 mutex_unlock(&ftrace_lock);
3916
3917 out_unlock:
3918 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3919 free_ftrace_hash(hash);
3920}
3921
3922void
3923unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3924 void *data)
3925{
3926 __unregister_ftrace_function_probe(glob, ops, data,
3927 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3928}
3929
3930void
3931unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3932{
3933 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3934}
3935
3936void unregister_ftrace_function_probe_all(char *glob)
3937{
3938 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3939}
3940
3941static LIST_HEAD(ftrace_commands);
3942static DEFINE_MUTEX(ftrace_cmd_mutex);
3943
3944/*
3945 * Currently we only register ftrace commands from __init, so mark this
3946 * __init too.
3947 */
3948__init int register_ftrace_command(struct ftrace_func_command *cmd)
3949{
3950 struct ftrace_func_command *p;
3951 int ret = 0;
3952
3953 mutex_lock(&ftrace_cmd_mutex);
3954 list_for_each_entry(p, &ftrace_commands, list) {
3955 if (strcmp(cmd->name, p->name) == 0) {
3956 ret = -EBUSY;
3957 goto out_unlock;
3958 }
3959 }
3960 list_add(&cmd->list, &ftrace_commands);
3961 out_unlock:
3962 mutex_unlock(&ftrace_cmd_mutex);
3963
3964 return ret;
3965}
3966
3967/*
3968 * Currently we only unregister ftrace commands from __init, so mark
3969 * this __init too.
3970 */
3971__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3972{
3973 struct ftrace_func_command *p, *n;
3974 int ret = -ENODEV;
3975
3976 mutex_lock(&ftrace_cmd_mutex);
3977 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3978 if (strcmp(cmd->name, p->name) == 0) {
3979 ret = 0;
3980 list_del_init(&p->list);
3981 goto out_unlock;
3982 }
3983 }
3984 out_unlock:
3985 mutex_unlock(&ftrace_cmd_mutex);
3986
3987 return ret;
3988}
3989
3990static int ftrace_process_regex(struct ftrace_hash *hash,
3991 char *buff, int len, int enable)
3992{
3993 char *func, *command, *next = buff;
3994 struct ftrace_func_command *p;
3995 int ret = -EINVAL;
3996
3997 func = strsep(&next, ":");
3998
3999 if (!next) {
4000 ret = ftrace_match_records(hash, func, len);
4001 if (!ret)
4002 ret = -EINVAL;
4003 if (ret < 0)
4004 return ret;
4005 return 0;
4006 }
4007
4008 /* command found */
4009
4010 command = strsep(&next, ":");
4011
4012 mutex_lock(&ftrace_cmd_mutex);
4013 list_for_each_entry(p, &ftrace_commands, list) {
4014 if (strcmp(p->name, command) == 0) {
4015 ret = p->func(hash, func, command, next, enable);
4016 goto out_unlock;
4017 }
4018 }
4019 out_unlock:
4020 mutex_unlock(&ftrace_cmd_mutex);
4021
4022 return ret;
4023}
4024
4025static ssize_t
4026ftrace_regex_write(struct file *file, const char __user *ubuf,
4027 size_t cnt, loff_t *ppos, int enable)
4028{
4029 struct ftrace_iterator *iter;
4030 struct trace_parser *parser;
4031 ssize_t ret, read;
4032
4033 if (!cnt)
4034 return 0;
4035
4036 if (file->f_mode & FMODE_READ) {
4037 struct seq_file *m = file->private_data;
4038 iter = m->private;
4039 } else
4040 iter = file->private_data;
4041
4042 if (unlikely(ftrace_disabled))
4043 return -ENODEV;
4044
4045 /* iter->hash is a local copy, so we don't need regex_lock */
4046
4047 parser = &iter->parser;
4048 read = trace_get_user(parser, ubuf, cnt, ppos);
4049
4050 if (read >= 0 && trace_parser_loaded(parser) &&
4051 !trace_parser_cont(parser)) {
4052 ret = ftrace_process_regex(iter->hash, parser->buffer,
4053 parser->idx, enable);
4054 trace_parser_clear(parser);
4055 if (ret < 0)
4056 goto out;
4057 }
4058
4059 ret = read;
4060 out:
4061 return ret;
4062}
4063
4064ssize_t
4065ftrace_filter_write(struct file *file, const char __user *ubuf,
4066 size_t cnt, loff_t *ppos)
4067{
4068 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4069}
4070
4071ssize_t
4072ftrace_notrace_write(struct file *file, const char __user *ubuf,
4073 size_t cnt, loff_t *ppos)
4074{
4075 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4076}
4077
4078static int
4079ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4080{
4081 struct ftrace_func_entry *entry;
4082
4083 if (!ftrace_location(ip))
4084 return -EINVAL;
4085
4086 if (remove) {
4087 entry = ftrace_lookup_ip(hash, ip);
4088 if (!entry)
4089 return -ENOENT;
4090 free_hash_entry(hash, entry);
4091 return 0;
4092 }
4093
4094 return add_hash_entry(hash, ip);
4095}
4096
4097static void ftrace_ops_update_code(struct ftrace_ops *ops,
4098 struct ftrace_ops_hash *old_hash)
4099{
4100 struct ftrace_ops *op;
4101
4102 if (!ftrace_enabled)
4103 return;
4104
4105 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4106 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4107 return;
4108 }
4109
4110 /*
4111 * If this is the shared global_ops filter, then we need to
4112 * check if there is another ops that shares it, is enabled.
4113 * If so, we still need to run the modify code.
4114 */
4115 if (ops->func_hash != &global_ops.local_hash)
4116 return;
4117
4118 do_for_each_ftrace_op(op, ftrace_ops_list) {
4119 if (op->func_hash == &global_ops.local_hash &&
4120 op->flags & FTRACE_OPS_FL_ENABLED) {
4121 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4122 /* Only need to do this once */
4123 return;
4124 }
4125 } while_for_each_ftrace_op(op);
4126}
4127
4128static int
4129ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4130 unsigned long ip, int remove, int reset, int enable)
4131{
4132 struct ftrace_hash **orig_hash;
4133 struct ftrace_ops_hash old_hash_ops;
4134 struct ftrace_hash *old_hash;
4135 struct ftrace_hash *hash;
4136 int ret;
4137
4138 if (unlikely(ftrace_disabled))
4139 return -ENODEV;
4140
4141 mutex_lock(&ops->func_hash->regex_lock);
4142
4143 if (enable)
4144 orig_hash = &ops->func_hash->filter_hash;
4145 else
4146 orig_hash = &ops->func_hash->notrace_hash;
4147
4148 if (reset)
4149 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4150 else
4151 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4152
4153 if (!hash) {
4154 ret = -ENOMEM;
4155 goto out_regex_unlock;
4156 }
4157
4158 if (buf && !ftrace_match_records(hash, buf, len)) {
4159 ret = -EINVAL;
4160 goto out_regex_unlock;
4161 }
4162 if (ip) {
4163 ret = ftrace_match_addr(hash, ip, remove);
4164 if (ret < 0)
4165 goto out_regex_unlock;
4166 }
4167
4168 mutex_lock(&ftrace_lock);
4169 old_hash = *orig_hash;
4170 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4171 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4172 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4173 if (!ret) {
4174 ftrace_ops_update_code(ops, &old_hash_ops);
4175 free_ftrace_hash_rcu(old_hash);
4176 }
4177 mutex_unlock(&ftrace_lock);
4178
4179 out_regex_unlock:
4180 mutex_unlock(&ops->func_hash->regex_lock);
4181
4182 free_ftrace_hash(hash);
4183 return ret;
4184}
4185
4186static int
4187ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4188 int reset, int enable)
4189{
4190 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4191}
4192
4193/**
4194 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4195 * @ops - the ops to set the filter with
4196 * @ip - the address to add to or remove from the filter.
4197 * @remove - non zero to remove the ip from the filter
4198 * @reset - non zero to reset all filters before applying this filter.
4199 *
4200 * Filters denote which functions should be enabled when tracing is enabled
4201 * If @ip is NULL, it failes to update filter.
4202 */
4203int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4204 int remove, int reset)
4205{
4206 ftrace_ops_init(ops);
4207 return ftrace_set_addr(ops, ip, remove, reset, 1);
4208}
4209EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4210
4211static int
4212ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4213 int reset, int enable)
4214{
4215 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4216}
4217
4218/**
4219 * ftrace_set_filter - set a function to filter on in ftrace
4220 * @ops - the ops to set the filter with
4221 * @buf - the string that holds the function filter text.
4222 * @len - the length of the string.
4223 * @reset - non zero to reset all filters before applying this filter.
4224 *
4225 * Filters denote which functions should be enabled when tracing is enabled.
4226 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4227 */
4228int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4229 int len, int reset)
4230{
4231 ftrace_ops_init(ops);
4232 return ftrace_set_regex(ops, buf, len, reset, 1);
4233}
4234EXPORT_SYMBOL_GPL(ftrace_set_filter);
4235
4236/**
4237 * ftrace_set_notrace - set a function to not trace in ftrace
4238 * @ops - the ops to set the notrace filter with
4239 * @buf - the string that holds the function notrace text.
4240 * @len - the length of the string.
4241 * @reset - non zero to reset all filters before applying this filter.
4242 *
4243 * Notrace Filters denote which functions should not be enabled when tracing
4244 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4245 * for tracing.
4246 */
4247int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4248 int len, int reset)
4249{
4250 ftrace_ops_init(ops);
4251 return ftrace_set_regex(ops, buf, len, reset, 0);
4252}
4253EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4254/**
4255 * ftrace_set_global_filter - set a function to filter on with global tracers
4256 * @buf - the string that holds the function filter text.
4257 * @len - the length of the string.
4258 * @reset - non zero to reset all filters before applying this filter.
4259 *
4260 * Filters denote which functions should be enabled when tracing is enabled.
4261 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4262 */
4263void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4264{
4265 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4266}
4267EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4268
4269/**
4270 * ftrace_set_global_notrace - set a function to not trace with global tracers
4271 * @buf - the string that holds the function notrace text.
4272 * @len - the length of the string.
4273 * @reset - non zero to reset all filters before applying this filter.
4274 *
4275 * Notrace Filters denote which functions should not be enabled when tracing
4276 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4277 * for tracing.
4278 */
4279void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4280{
4281 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4282}
4283EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4284
4285/*
4286 * command line interface to allow users to set filters on boot up.
4287 */
4288#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4289static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4290static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4291
4292/* Used by function selftest to not test if filter is set */
4293bool ftrace_filter_param __initdata;
4294
4295static int __init set_ftrace_notrace(char *str)
4296{
4297 ftrace_filter_param = true;
4298 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4299 return 1;
4300}
4301__setup("ftrace_notrace=", set_ftrace_notrace);
4302
4303static int __init set_ftrace_filter(char *str)
4304{
4305 ftrace_filter_param = true;
4306 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4307 return 1;
4308}
4309__setup("ftrace_filter=", set_ftrace_filter);
4310
4311#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4312static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4313static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4314static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4315
4316static unsigned long save_global_trampoline;
4317static unsigned long save_global_flags;
4318
4319static int __init set_graph_function(char *str)
4320{
4321 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4322 return 1;
4323}
4324__setup("ftrace_graph_filter=", set_graph_function);
4325
4326static int __init set_graph_notrace_function(char *str)
4327{
4328 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4329 return 1;
4330}
4331__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4332
4333static void __init set_ftrace_early_graph(char *buf, int enable)
4334{
4335 int ret;
4336 char *func;
4337 unsigned long *table = ftrace_graph_funcs;
4338 int *count = &ftrace_graph_count;
4339
4340 if (!enable) {
4341 table = ftrace_graph_notrace_funcs;
4342 count = &ftrace_graph_notrace_count;
4343 }
4344
4345 while (buf) {
4346 func = strsep(&buf, ",");
4347 /* we allow only one expression at a time */
4348 ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4349 if (ret)
4350 printk(KERN_DEBUG "ftrace: function %s not "
4351 "traceable\n", func);
4352 }
4353}
4354#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4355
4356void __init
4357ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4358{
4359 char *func;
4360
4361 ftrace_ops_init(ops);
4362
4363 while (buf) {
4364 func = strsep(&buf, ",");
4365 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4366 }
4367}
4368
4369static void __init set_ftrace_early_filters(void)
4370{
4371 if (ftrace_filter_buf[0])
4372 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4373 if (ftrace_notrace_buf[0])
4374 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4375#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4376 if (ftrace_graph_buf[0])
4377 set_ftrace_early_graph(ftrace_graph_buf, 1);
4378 if (ftrace_graph_notrace_buf[0])
4379 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4380#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4381}
4382
4383int ftrace_regex_release(struct inode *inode, struct file *file)
4384{
4385 struct seq_file *m = (struct seq_file *)file->private_data;
4386 struct ftrace_ops_hash old_hash_ops;
4387 struct ftrace_iterator *iter;
4388 struct ftrace_hash **orig_hash;
4389 struct ftrace_hash *old_hash;
4390 struct trace_parser *parser;
4391 int filter_hash;
4392 int ret;
4393
4394 if (file->f_mode & FMODE_READ) {
4395 iter = m->private;
4396 seq_release(inode, file);
4397 } else
4398 iter = file->private_data;
4399
4400 parser = &iter->parser;
4401 if (trace_parser_loaded(parser)) {
4402 parser->buffer[parser->idx] = 0;
4403 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4404 }
4405
4406 trace_parser_put(parser);
4407
4408 mutex_lock(&iter->ops->func_hash->regex_lock);
4409
4410 if (file->f_mode & FMODE_WRITE) {
4411 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4412
4413 if (filter_hash)
4414 orig_hash = &iter->ops->func_hash->filter_hash;
4415 else
4416 orig_hash = &iter->ops->func_hash->notrace_hash;
4417
4418 mutex_lock(&ftrace_lock);
4419 old_hash = *orig_hash;
4420 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4421 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4422 ret = ftrace_hash_move(iter->ops, filter_hash,
4423 orig_hash, iter->hash);
4424 if (!ret) {
4425 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4426 free_ftrace_hash_rcu(old_hash);
4427 }
4428 mutex_unlock(&ftrace_lock);
4429 }
4430
4431 mutex_unlock(&iter->ops->func_hash->regex_lock);
4432 free_ftrace_hash(iter->hash);
4433 kfree(iter);
4434
4435 return 0;
4436}
4437
4438static const struct file_operations ftrace_avail_fops = {
4439 .open = ftrace_avail_open,
4440 .read = seq_read,
4441 .llseek = seq_lseek,
4442 .release = seq_release_private,
4443};
4444
4445static const struct file_operations ftrace_enabled_fops = {
4446 .open = ftrace_enabled_open,
4447 .read = seq_read,
4448 .llseek = seq_lseek,
4449 .release = seq_release_private,
4450};
4451
4452static const struct file_operations ftrace_filter_fops = {
4453 .open = ftrace_filter_open,
4454 .read = seq_read,
4455 .write = ftrace_filter_write,
4456 .llseek = tracing_lseek,
4457 .release = ftrace_regex_release,
4458};
4459
4460static const struct file_operations ftrace_notrace_fops = {
4461 .open = ftrace_notrace_open,
4462 .read = seq_read,
4463 .write = ftrace_notrace_write,
4464 .llseek = tracing_lseek,
4465 .release = ftrace_regex_release,
4466};
4467
4468#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4469
4470static DEFINE_MUTEX(graph_lock);
4471
4472int ftrace_graph_count;
4473int ftrace_graph_notrace_count;
4474unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4475unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4476
4477struct ftrace_graph_data {
4478 unsigned long *table;
4479 size_t size;
4480 int *count;
4481 const struct seq_operations *seq_ops;
4482};
4483
4484static void *
4485__g_next(struct seq_file *m, loff_t *pos)
4486{
4487 struct ftrace_graph_data *fgd = m->private;
4488
4489 if (*pos >= *fgd->count)
4490 return NULL;
4491 return &fgd->table[*pos];
4492}
4493
4494static void *
4495g_next(struct seq_file *m, void *v, loff_t *pos)
4496{
4497 (*pos)++;
4498 return __g_next(m, pos);
4499}
4500
4501static void *g_start(struct seq_file *m, loff_t *pos)
4502{
4503 struct ftrace_graph_data *fgd = m->private;
4504
4505 mutex_lock(&graph_lock);
4506
4507 /* Nothing, tell g_show to print all functions are enabled */
4508 if (!*fgd->count && !*pos)
4509 return (void *)1;
4510
4511 return __g_next(m, pos);
4512}
4513
4514static void g_stop(struct seq_file *m, void *p)
4515{
4516 mutex_unlock(&graph_lock);
4517}
4518
4519static int g_show(struct seq_file *m, void *v)
4520{
4521 unsigned long *ptr = v;
4522
4523 if (!ptr)
4524 return 0;
4525
4526 if (ptr == (unsigned long *)1) {
4527 struct ftrace_graph_data *fgd = m->private;
4528
4529 if (fgd->table == ftrace_graph_funcs)
4530 seq_puts(m, "#### all functions enabled ####\n");
4531 else
4532 seq_puts(m, "#### no functions disabled ####\n");
4533 return 0;
4534 }
4535
4536 seq_printf(m, "%ps\n", (void *)*ptr);
4537
4538 return 0;
4539}
4540
4541static const struct seq_operations ftrace_graph_seq_ops = {
4542 .start = g_start,
4543 .next = g_next,
4544 .stop = g_stop,
4545 .show = g_show,
4546};
4547
4548static int
4549__ftrace_graph_open(struct inode *inode, struct file *file,
4550 struct ftrace_graph_data *fgd)
4551{
4552 int ret = 0;
4553
4554 mutex_lock(&graph_lock);
4555 if ((file->f_mode & FMODE_WRITE) &&
4556 (file->f_flags & O_TRUNC)) {
4557 *fgd->count = 0;
4558 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4559 }
4560 mutex_unlock(&graph_lock);
4561
4562 if (file->f_mode & FMODE_READ) {
4563 ret = seq_open(file, fgd->seq_ops);
4564 if (!ret) {
4565 struct seq_file *m = file->private_data;
4566 m->private = fgd;
4567 }
4568 } else
4569 file->private_data = fgd;
4570
4571 return ret;
4572}
4573
4574static int
4575ftrace_graph_open(struct inode *inode, struct file *file)
4576{
4577 struct ftrace_graph_data *fgd;
4578
4579 if (unlikely(ftrace_disabled))
4580 return -ENODEV;
4581
4582 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4583 if (fgd == NULL)
4584 return -ENOMEM;
4585
4586 fgd->table = ftrace_graph_funcs;
4587 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4588 fgd->count = &ftrace_graph_count;
4589 fgd->seq_ops = &ftrace_graph_seq_ops;
4590
4591 return __ftrace_graph_open(inode, file, fgd);
4592}
4593
4594static int
4595ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4596{
4597 struct ftrace_graph_data *fgd;
4598
4599 if (unlikely(ftrace_disabled))
4600 return -ENODEV;
4601
4602 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4603 if (fgd == NULL)
4604 return -ENOMEM;
4605
4606 fgd->table = ftrace_graph_notrace_funcs;
4607 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4608 fgd->count = &ftrace_graph_notrace_count;
4609 fgd->seq_ops = &ftrace_graph_seq_ops;
4610
4611 return __ftrace_graph_open(inode, file, fgd);
4612}
4613
4614static int
4615ftrace_graph_release(struct inode *inode, struct file *file)
4616{
4617 if (file->f_mode & FMODE_READ) {
4618 struct seq_file *m = file->private_data;
4619
4620 kfree(m->private);
4621 seq_release(inode, file);
4622 } else {
4623 kfree(file->private_data);
4624 }
4625
4626 return 0;
4627}
4628
4629static int
4630ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4631{
4632 struct ftrace_glob func_g;
4633 struct dyn_ftrace *rec;
4634 struct ftrace_page *pg;
4635 int fail = 1;
4636 int not;
4637 bool exists;
4638 int i;
4639
4640 /* decode regex */
4641 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4642 &func_g.search, ¬);
4643 if (!not && *idx >= size)
4644 return -EBUSY;
4645
4646 func_g.len = strlen(func_g.search);
4647
4648 mutex_lock(&ftrace_lock);
4649
4650 if (unlikely(ftrace_disabled)) {
4651 mutex_unlock(&ftrace_lock);
4652 return -ENODEV;
4653 }
4654
4655 do_for_each_ftrace_rec(pg, rec) {
4656
4657 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4658 /* if it is in the array */
4659 exists = false;
4660 for (i = 0; i < *idx; i++) {
4661 if (array[i] == rec->ip) {
4662 exists = true;
4663 break;
4664 }
4665 }
4666
4667 if (!not) {
4668 fail = 0;
4669 if (!exists) {
4670 array[(*idx)++] = rec->ip;
4671 if (*idx >= size)
4672 goto out;
4673 }
4674 } else {
4675 if (exists) {
4676 array[i] = array[--(*idx)];
4677 array[*idx] = 0;
4678 fail = 0;
4679 }
4680 }
4681 }
4682 } while_for_each_ftrace_rec();
4683out:
4684 mutex_unlock(&ftrace_lock);
4685
4686 if (fail)
4687 return -EINVAL;
4688
4689 return 0;
4690}
4691
4692static ssize_t
4693ftrace_graph_write(struct file *file, const char __user *ubuf,
4694 size_t cnt, loff_t *ppos)
4695{
4696 struct trace_parser parser;
4697 ssize_t read, ret = 0;
4698 struct ftrace_graph_data *fgd = file->private_data;
4699
4700 if (!cnt)
4701 return 0;
4702
4703 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4704 return -ENOMEM;
4705
4706 read = trace_get_user(&parser, ubuf, cnt, ppos);
4707
4708 if (read >= 0 && trace_parser_loaded((&parser))) {
4709 parser.buffer[parser.idx] = 0;
4710
4711 mutex_lock(&graph_lock);
4712
4713 /* we allow only one expression at a time */
4714 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4715 parser.buffer);
4716
4717 mutex_unlock(&graph_lock);
4718 }
4719
4720 if (!ret)
4721 ret = read;
4722
4723 trace_parser_put(&parser);
4724
4725 return ret;
4726}
4727
4728static const struct file_operations ftrace_graph_fops = {
4729 .open = ftrace_graph_open,
4730 .read = seq_read,
4731 .write = ftrace_graph_write,
4732 .llseek = tracing_lseek,
4733 .release = ftrace_graph_release,
4734};
4735
4736static const struct file_operations ftrace_graph_notrace_fops = {
4737 .open = ftrace_graph_notrace_open,
4738 .read = seq_read,
4739 .write = ftrace_graph_write,
4740 .llseek = tracing_lseek,
4741 .release = ftrace_graph_release,
4742};
4743#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4744
4745void ftrace_create_filter_files(struct ftrace_ops *ops,
4746 struct dentry *parent)
4747{
4748
4749 trace_create_file("set_ftrace_filter", 0644, parent,
4750 ops, &ftrace_filter_fops);
4751
4752 trace_create_file("set_ftrace_notrace", 0644, parent,
4753 ops, &ftrace_notrace_fops);
4754}
4755
4756/*
4757 * The name "destroy_filter_files" is really a misnomer. Although
4758 * in the future, it may actualy delete the files, but this is
4759 * really intended to make sure the ops passed in are disabled
4760 * and that when this function returns, the caller is free to
4761 * free the ops.
4762 *
4763 * The "destroy" name is only to match the "create" name that this
4764 * should be paired with.
4765 */
4766void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4767{
4768 mutex_lock(&ftrace_lock);
4769 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4770 ftrace_shutdown(ops, 0);
4771 ops->flags |= FTRACE_OPS_FL_DELETED;
4772 mutex_unlock(&ftrace_lock);
4773}
4774
4775static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4776{
4777
4778 trace_create_file("available_filter_functions", 0444,
4779 d_tracer, NULL, &ftrace_avail_fops);
4780
4781 trace_create_file("enabled_functions", 0444,
4782 d_tracer, NULL, &ftrace_enabled_fops);
4783
4784 ftrace_create_filter_files(&global_ops, d_tracer);
4785
4786#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4787 trace_create_file("set_graph_function", 0444, d_tracer,
4788 NULL,
4789 &ftrace_graph_fops);
4790 trace_create_file("set_graph_notrace", 0444, d_tracer,
4791 NULL,
4792 &ftrace_graph_notrace_fops);
4793#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4794
4795 return 0;
4796}
4797
4798static int ftrace_cmp_ips(const void *a, const void *b)
4799{
4800 const unsigned long *ipa = a;
4801 const unsigned long *ipb = b;
4802
4803 if (*ipa > *ipb)
4804 return 1;
4805 if (*ipa < *ipb)
4806 return -1;
4807 return 0;
4808}
4809
4810static int ftrace_process_locs(struct module *mod,
4811 unsigned long *start,
4812 unsigned long *end)
4813{
4814 struct ftrace_page *start_pg;
4815 struct ftrace_page *pg;
4816 struct dyn_ftrace *rec;
4817 unsigned long count;
4818 unsigned long *p;
4819 unsigned long addr;
4820 unsigned long flags = 0; /* Shut up gcc */
4821 int ret = -ENOMEM;
4822
4823 count = end - start;
4824
4825 if (!count)
4826 return 0;
4827
4828 sort(start, count, sizeof(*start),
4829 ftrace_cmp_ips, NULL);
4830
4831 start_pg = ftrace_allocate_pages(count);
4832 if (!start_pg)
4833 return -ENOMEM;
4834
4835 mutex_lock(&ftrace_lock);
4836
4837 /*
4838 * Core and each module needs their own pages, as
4839 * modules will free them when they are removed.
4840 * Force a new page to be allocated for modules.
4841 */
4842 if (!mod) {
4843 WARN_ON(ftrace_pages || ftrace_pages_start);
4844 /* First initialization */
4845 ftrace_pages = ftrace_pages_start = start_pg;
4846 } else {
4847 if (!ftrace_pages)
4848 goto out;
4849
4850 if (WARN_ON(ftrace_pages->next)) {
4851 /* Hmm, we have free pages? */
4852 while (ftrace_pages->next)
4853 ftrace_pages = ftrace_pages->next;
4854 }
4855
4856 ftrace_pages->next = start_pg;
4857 }
4858
4859 p = start;
4860 pg = start_pg;
4861 while (p < end) {
4862 addr = ftrace_call_adjust(*p++);
4863 /*
4864 * Some architecture linkers will pad between
4865 * the different mcount_loc sections of different
4866 * object files to satisfy alignments.
4867 * Skip any NULL pointers.
4868 */
4869 if (!addr)
4870 continue;
4871
4872 if (pg->index == pg->size) {
4873 /* We should have allocated enough */
4874 if (WARN_ON(!pg->next))
4875 break;
4876 pg = pg->next;
4877 }
4878
4879 rec = &pg->records[pg->index++];
4880 rec->ip = addr;
4881 }
4882
4883 /* We should have used all pages */
4884 WARN_ON(pg->next);
4885
4886 /* Assign the last page to ftrace_pages */
4887 ftrace_pages = pg;
4888
4889 /*
4890 * We only need to disable interrupts on start up
4891 * because we are modifying code that an interrupt
4892 * may execute, and the modification is not atomic.
4893 * But for modules, nothing runs the code we modify
4894 * until we are finished with it, and there's no
4895 * reason to cause large interrupt latencies while we do it.
4896 */
4897 if (!mod)
4898 local_irq_save(flags);
4899 ftrace_update_code(mod, start_pg);
4900 if (!mod)
4901 local_irq_restore(flags);
4902 ret = 0;
4903 out:
4904 mutex_unlock(&ftrace_lock);
4905
4906 return ret;
4907}
4908
4909#ifdef CONFIG_MODULES
4910
4911#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4912
4913static int referenced_filters(struct dyn_ftrace *rec)
4914{
4915 struct ftrace_ops *ops;
4916 int cnt = 0;
4917
4918 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
4919 if (ops_references_rec(ops, rec))
4920 cnt++;
4921 }
4922
4923 return cnt;
4924}
4925
4926void ftrace_release_mod(struct module *mod)
4927{
4928 struct dyn_ftrace *rec;
4929 struct ftrace_page **last_pg;
4930 struct ftrace_page *pg;
4931 int order;
4932
4933 mutex_lock(&ftrace_lock);
4934
4935 if (ftrace_disabled)
4936 goto out_unlock;
4937
4938 /*
4939 * Each module has its own ftrace_pages, remove
4940 * them from the list.
4941 */
4942 last_pg = &ftrace_pages_start;
4943 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4944 rec = &pg->records[0];
4945 if (within_module_core(rec->ip, mod)) {
4946 /*
4947 * As core pages are first, the first
4948 * page should never be a module page.
4949 */
4950 if (WARN_ON(pg == ftrace_pages_start))
4951 goto out_unlock;
4952
4953 /* Check if we are deleting the last page */
4954 if (pg == ftrace_pages)
4955 ftrace_pages = next_to_ftrace_page(last_pg);
4956
4957 *last_pg = pg->next;
4958 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4959 free_pages((unsigned long)pg->records, order);
4960 kfree(pg);
4961 } else
4962 last_pg = &pg->next;
4963 }
4964 out_unlock:
4965 mutex_unlock(&ftrace_lock);
4966}
4967
4968void ftrace_module_enable(struct module *mod)
4969{
4970 struct dyn_ftrace *rec;
4971 struct ftrace_page *pg;
4972
4973 mutex_lock(&ftrace_lock);
4974
4975 if (ftrace_disabled)
4976 goto out_unlock;
4977
4978 /*
4979 * If the tracing is enabled, go ahead and enable the record.
4980 *
4981 * The reason not to enable the record immediatelly is the
4982 * inherent check of ftrace_make_nop/ftrace_make_call for
4983 * correct previous instructions. Making first the NOP
4984 * conversion puts the module to the correct state, thus
4985 * passing the ftrace_make_call check.
4986 *
4987 * We also delay this to after the module code already set the
4988 * text to read-only, as we now need to set it back to read-write
4989 * so that we can modify the text.
4990 */
4991 if (ftrace_start_up)
4992 ftrace_arch_code_modify_prepare();
4993
4994 do_for_each_ftrace_rec(pg, rec) {
4995 int cnt;
4996 /*
4997 * do_for_each_ftrace_rec() is a double loop.
4998 * module text shares the pg. If a record is
4999 * not part of this module, then skip this pg,
5000 * which the "break" will do.
5001 */
5002 if (!within_module_core(rec->ip, mod))
5003 break;
5004
5005 cnt = 0;
5006
5007 /*
5008 * When adding a module, we need to check if tracers are
5009 * currently enabled and if they are, and can trace this record,
5010 * we need to enable the module functions as well as update the
5011 * reference counts for those function records.
5012 */
5013 if (ftrace_start_up)
5014 cnt += referenced_filters(rec);
5015
5016 /* This clears FTRACE_FL_DISABLED */
5017 rec->flags = cnt;
5018
5019 if (ftrace_start_up && cnt) {
5020 int failed = __ftrace_replace_code(rec, 1);
5021 if (failed) {
5022 ftrace_bug(failed, rec);
5023 goto out_loop;
5024 }
5025 }
5026
5027 } while_for_each_ftrace_rec();
5028
5029 out_loop:
5030 if (ftrace_start_up)
5031 ftrace_arch_code_modify_post_process();
5032
5033 out_unlock:
5034 mutex_unlock(&ftrace_lock);
5035}
5036
5037void ftrace_module_init(struct module *mod)
5038{
5039 if (ftrace_disabled || !mod->num_ftrace_callsites)
5040 return;
5041
5042 ftrace_process_locs(mod, mod->ftrace_callsites,
5043 mod->ftrace_callsites + mod->num_ftrace_callsites);
5044}
5045#endif /* CONFIG_MODULES */
5046
5047void __init ftrace_init(void)
5048{
5049 extern unsigned long __start_mcount_loc[];
5050 extern unsigned long __stop_mcount_loc[];
5051 unsigned long count, flags;
5052 int ret;
5053
5054 local_irq_save(flags);
5055 ret = ftrace_dyn_arch_init();
5056 local_irq_restore(flags);
5057 if (ret)
5058 goto failed;
5059
5060 count = __stop_mcount_loc - __start_mcount_loc;
5061 if (!count) {
5062 pr_info("ftrace: No functions to be traced?\n");
5063 goto failed;
5064 }
5065
5066 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5067 count, count / ENTRIES_PER_PAGE + 1);
5068
5069 last_ftrace_enabled = ftrace_enabled = 1;
5070
5071 ret = ftrace_process_locs(NULL,
5072 __start_mcount_loc,
5073 __stop_mcount_loc);
5074
5075 set_ftrace_early_filters();
5076
5077 return;
5078 failed:
5079 ftrace_disabled = 1;
5080}
5081
5082/* Do nothing if arch does not support this */
5083void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5084{
5085}
5086
5087static void ftrace_update_trampoline(struct ftrace_ops *ops)
5088{
5089
5090/*
5091 * Currently there's no safe way to free a trampoline when the kernel
5092 * is configured with PREEMPT. That is because a task could be preempted
5093 * when it jumped to the trampoline, it may be preempted for a long time
5094 * depending on the system load, and currently there's no way to know
5095 * when it will be off the trampoline. If the trampoline is freed
5096 * too early, when the task runs again, it will be executing on freed
5097 * memory and crash.
5098 */
5099#ifdef CONFIG_PREEMPT
5100 /* Currently, only non dynamic ops can have a trampoline */
5101 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5102 return;
5103#endif
5104
5105 arch_ftrace_update_trampoline(ops);
5106}
5107
5108#else
5109
5110static struct ftrace_ops global_ops = {
5111 .func = ftrace_stub,
5112 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5113 FTRACE_OPS_FL_INITIALIZED |
5114 FTRACE_OPS_FL_PID,
5115};
5116
5117static int __init ftrace_nodyn_init(void)
5118{
5119 ftrace_enabled = 1;
5120 return 0;
5121}
5122core_initcall(ftrace_nodyn_init);
5123
5124static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5125static inline void ftrace_startup_enable(int command) { }
5126static inline void ftrace_startup_all(int command) { }
5127/* Keep as macros so we do not need to define the commands */
5128# define ftrace_startup(ops, command) \
5129 ({ \
5130 int ___ret = __register_ftrace_function(ops); \
5131 if (!___ret) \
5132 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5133 ___ret; \
5134 })
5135# define ftrace_shutdown(ops, command) \
5136 ({ \
5137 int ___ret = __unregister_ftrace_function(ops); \
5138 if (!___ret) \
5139 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5140 ___ret; \
5141 })
5142
5143# define ftrace_startup_sysctl() do { } while (0)
5144# define ftrace_shutdown_sysctl() do { } while (0)
5145
5146static inline int
5147ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5148{
5149 return 1;
5150}
5151
5152static void ftrace_update_trampoline(struct ftrace_ops *ops)
5153{
5154}
5155
5156#endif /* CONFIG_DYNAMIC_FTRACE */
5157
5158__init void ftrace_init_global_array_ops(struct trace_array *tr)
5159{
5160 tr->ops = &global_ops;
5161 tr->ops->private = tr;
5162}
5163
5164void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5165{
5166 /* If we filter on pids, update to use the pid function */
5167 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5168 if (WARN_ON(tr->ops->func != ftrace_stub))
5169 printk("ftrace ops had %pS for function\n",
5170 tr->ops->func);
5171 }
5172 tr->ops->func = func;
5173 tr->ops->private = tr;
5174}
5175
5176void ftrace_reset_array_ops(struct trace_array *tr)
5177{
5178 tr->ops->func = ftrace_stub;
5179}
5180
5181static inline void
5182__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5183 struct ftrace_ops *ignored, struct pt_regs *regs)
5184{
5185 struct ftrace_ops *op;
5186 int bit;
5187
5188 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5189 if (bit < 0)
5190 return;
5191
5192 /*
5193 * Some of the ops may be dynamically allocated,
5194 * they must be freed after a synchronize_sched().
5195 */
5196 preempt_disable_notrace();
5197
5198 do_for_each_ftrace_op(op, ftrace_ops_list) {
5199 /*
5200 * Check the following for each ops before calling their func:
5201 * if RCU flag is set, then rcu_is_watching() must be true
5202 * if PER_CPU is set, then ftrace_function_local_disable()
5203 * must be false
5204 * Otherwise test if the ip matches the ops filter
5205 *
5206 * If any of the above fails then the op->func() is not executed.
5207 */
5208 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5209 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5210 !ftrace_function_local_disabled(op)) &&
5211 ftrace_ops_test(op, ip, regs)) {
5212
5213 if (FTRACE_WARN_ON(!op->func)) {
5214 pr_warn("op=%p %pS\n", op, op);
5215 goto out;
5216 }
5217 op->func(ip, parent_ip, op, regs);
5218 }
5219 } while_for_each_ftrace_op(op);
5220out:
5221 preempt_enable_notrace();
5222 trace_clear_recursion(bit);
5223}
5224
5225/*
5226 * Some archs only support passing ip and parent_ip. Even though
5227 * the list function ignores the op parameter, we do not want any
5228 * C side effects, where a function is called without the caller
5229 * sending a third parameter.
5230 * Archs are to support both the regs and ftrace_ops at the same time.
5231 * If they support ftrace_ops, it is assumed they support regs.
5232 * If call backs want to use regs, they must either check for regs
5233 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5234 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5235 * An architecture can pass partial regs with ftrace_ops and still
5236 * set the ARCH_SUPPORTS_FTRACE_OPS.
5237 */
5238#if ARCH_SUPPORTS_FTRACE_OPS
5239static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5240 struct ftrace_ops *op, struct pt_regs *regs)
5241{
5242 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5243}
5244#else
5245static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5246{
5247 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5248}
5249#endif
5250
5251/*
5252 * If there's only one function registered but it does not support
5253 * recursion, needs RCU protection and/or requires per cpu handling, then
5254 * this function will be called by the mcount trampoline.
5255 */
5256static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
5257 struct ftrace_ops *op, struct pt_regs *regs)
5258{
5259 int bit;
5260
5261 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
5262 return;
5263
5264 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5265 if (bit < 0)
5266 return;
5267
5268 preempt_disable_notrace();
5269
5270 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5271 !ftrace_function_local_disabled(op)) {
5272 op->func(ip, parent_ip, op, regs);
5273 }
5274
5275 preempt_enable_notrace();
5276 trace_clear_recursion(bit);
5277}
5278
5279/**
5280 * ftrace_ops_get_func - get the function a trampoline should call
5281 * @ops: the ops to get the function for
5282 *
5283 * Normally the mcount trampoline will call the ops->func, but there
5284 * are times that it should not. For example, if the ops does not
5285 * have its own recursion protection, then it should call the
5286 * ftrace_ops_recurs_func() instead.
5287 *
5288 * Returns the function that the trampoline should call for @ops.
5289 */
5290ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5291{
5292 /*
5293 * If the function does not handle recursion, needs to be RCU safe,
5294 * or does per cpu logic, then we need to call the assist handler.
5295 */
5296 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
5297 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
5298 return ftrace_ops_assist_func;
5299
5300 return ops->func;
5301}
5302
5303static void clear_ftrace_swapper(void)
5304{
5305 struct task_struct *p;
5306 int cpu;
5307
5308 get_online_cpus();
5309 for_each_online_cpu(cpu) {
5310 p = idle_task(cpu);
5311 clear_tsk_trace_trace(p);
5312 }
5313 put_online_cpus();
5314}
5315
5316static void set_ftrace_swapper(void)
5317{
5318 struct task_struct *p;
5319 int cpu;
5320
5321 get_online_cpus();
5322 for_each_online_cpu(cpu) {
5323 p = idle_task(cpu);
5324 set_tsk_trace_trace(p);
5325 }
5326 put_online_cpus();
5327}
5328
5329static void clear_ftrace_pid(struct pid *pid)
5330{
5331 struct task_struct *p;
5332
5333 rcu_read_lock();
5334 do_each_pid_task(pid, PIDTYPE_PID, p) {
5335 clear_tsk_trace_trace(p);
5336 } while_each_pid_task(pid, PIDTYPE_PID, p);
5337 rcu_read_unlock();
5338
5339 put_pid(pid);
5340}
5341
5342static void set_ftrace_pid(struct pid *pid)
5343{
5344 struct task_struct *p;
5345
5346 rcu_read_lock();
5347 do_each_pid_task(pid, PIDTYPE_PID, p) {
5348 set_tsk_trace_trace(p);
5349 } while_each_pid_task(pid, PIDTYPE_PID, p);
5350 rcu_read_unlock();
5351}
5352
5353static void clear_ftrace_pid_task(struct pid *pid)
5354{
5355 if (pid == ftrace_swapper_pid)
5356 clear_ftrace_swapper();
5357 else
5358 clear_ftrace_pid(pid);
5359}
5360
5361static void set_ftrace_pid_task(struct pid *pid)
5362{
5363 if (pid == ftrace_swapper_pid)
5364 set_ftrace_swapper();
5365 else
5366 set_ftrace_pid(pid);
5367}
5368
5369static int ftrace_pid_add(int p)
5370{
5371 struct pid *pid;
5372 struct ftrace_pid *fpid;
5373 int ret = -EINVAL;
5374
5375 mutex_lock(&ftrace_lock);
5376
5377 if (!p)
5378 pid = ftrace_swapper_pid;
5379 else
5380 pid = find_get_pid(p);
5381
5382 if (!pid)
5383 goto out;
5384
5385 ret = 0;
5386
5387 list_for_each_entry(fpid, &ftrace_pids, list)
5388 if (fpid->pid == pid)
5389 goto out_put;
5390
5391 ret = -ENOMEM;
5392
5393 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
5394 if (!fpid)
5395 goto out_put;
5396
5397 list_add(&fpid->list, &ftrace_pids);
5398 fpid->pid = pid;
5399
5400 set_ftrace_pid_task(pid);
5401
5402 ftrace_update_pid_func();
5403
5404 ftrace_startup_all(0);
5405
5406 mutex_unlock(&ftrace_lock);
5407 return 0;
5408
5409out_put:
5410 if (pid != ftrace_swapper_pid)
5411 put_pid(pid);
5412
5413out:
5414 mutex_unlock(&ftrace_lock);
5415 return ret;
5416}
5417
5418static void ftrace_pid_reset(void)
5419{
5420 struct ftrace_pid *fpid, *safe;
5421
5422 mutex_lock(&ftrace_lock);
5423 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
5424 struct pid *pid = fpid->pid;
5425
5426 clear_ftrace_pid_task(pid);
5427
5428 list_del(&fpid->list);
5429 kfree(fpid);
5430 }
5431
5432 ftrace_update_pid_func();
5433 ftrace_startup_all(0);
5434
5435 mutex_unlock(&ftrace_lock);
5436}
5437
5438static void *fpid_start(struct seq_file *m, loff_t *pos)
5439{
5440 mutex_lock(&ftrace_lock);
5441
5442 if (!ftrace_pids_enabled() && (!*pos))
5443 return (void *) 1;
5444
5445 return seq_list_start(&ftrace_pids, *pos);
5446}
5447
5448static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5449{
5450 if (v == (void *)1)
5451 return NULL;
5452
5453 return seq_list_next(v, &ftrace_pids, pos);
5454}
5455
5456static void fpid_stop(struct seq_file *m, void *p)
5457{
5458 mutex_unlock(&ftrace_lock);
5459}
5460
5461static int fpid_show(struct seq_file *m, void *v)
5462{
5463 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
5464
5465 if (v == (void *)1) {
5466 seq_puts(m, "no pid\n");
5467 return 0;
5468 }
5469
5470 if (fpid->pid == ftrace_swapper_pid)
5471 seq_puts(m, "swapper tasks\n");
5472 else
5473 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
5474
5475 return 0;
5476}
5477
5478static const struct seq_operations ftrace_pid_sops = {
5479 .start = fpid_start,
5480 .next = fpid_next,
5481 .stop = fpid_stop,
5482 .show = fpid_show,
5483};
5484
5485static int
5486ftrace_pid_open(struct inode *inode, struct file *file)
5487{
5488 int ret = 0;
5489
5490 if ((file->f_mode & FMODE_WRITE) &&
5491 (file->f_flags & O_TRUNC))
5492 ftrace_pid_reset();
5493
5494 if (file->f_mode & FMODE_READ)
5495 ret = seq_open(file, &ftrace_pid_sops);
5496
5497 return ret;
5498}
5499
5500static ssize_t
5501ftrace_pid_write(struct file *filp, const char __user *ubuf,
5502 size_t cnt, loff_t *ppos)
5503{
5504 char buf[64], *tmp;
5505 long val;
5506 int ret;
5507
5508 if (cnt >= sizeof(buf))
5509 return -EINVAL;
5510
5511 if (copy_from_user(&buf, ubuf, cnt))
5512 return -EFAULT;
5513
5514 buf[cnt] = 0;
5515
5516 /*
5517 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
5518 * to clean the filter quietly.
5519 */
5520 tmp = strstrip(buf);
5521 if (strlen(tmp) == 0)
5522 return 1;
5523
5524 ret = kstrtol(tmp, 10, &val);
5525 if (ret < 0)
5526 return ret;
5527
5528 ret = ftrace_pid_add(val);
5529
5530 return ret ? ret : cnt;
5531}
5532
5533static int
5534ftrace_pid_release(struct inode *inode, struct file *file)
5535{
5536 if (file->f_mode & FMODE_READ)
5537 seq_release(inode, file);
5538
5539 return 0;
5540}
5541
5542static const struct file_operations ftrace_pid_fops = {
5543 .open = ftrace_pid_open,
5544 .write = ftrace_pid_write,
5545 .read = seq_read,
5546 .llseek = tracing_lseek,
5547 .release = ftrace_pid_release,
5548};
5549
5550static __init int ftrace_init_tracefs(void)
5551{
5552 struct dentry *d_tracer;
5553
5554 d_tracer = tracing_init_dentry();
5555 if (IS_ERR(d_tracer))
5556 return 0;
5557
5558 ftrace_init_dyn_tracefs(d_tracer);
5559
5560 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5561 NULL, &ftrace_pid_fops);
5562
5563 ftrace_profile_tracefs(d_tracer);
5564
5565 return 0;
5566}
5567fs_initcall(ftrace_init_tracefs);
5568
5569/**
5570 * ftrace_kill - kill ftrace
5571 *
5572 * This function should be used by panic code. It stops ftrace
5573 * but in a not so nice way. If you need to simply kill ftrace
5574 * from a non-atomic section, use ftrace_kill.
5575 */
5576void ftrace_kill(void)
5577{
5578 ftrace_disabled = 1;
5579 ftrace_enabled = 0;
5580 clear_ftrace_function();
5581}
5582
5583/**
5584 * Test if ftrace is dead or not.
5585 */
5586int ftrace_is_dead(void)
5587{
5588 return ftrace_disabled;
5589}
5590
5591/**
5592 * register_ftrace_function - register a function for profiling
5593 * @ops - ops structure that holds the function for profiling.
5594 *
5595 * Register a function to be called by all functions in the
5596 * kernel.
5597 *
5598 * Note: @ops->func and all the functions it calls must be labeled
5599 * with "notrace", otherwise it will go into a
5600 * recursive loop.
5601 */
5602int register_ftrace_function(struct ftrace_ops *ops)
5603{
5604 int ret = -1;
5605
5606 ftrace_ops_init(ops);
5607
5608 mutex_lock(&ftrace_lock);
5609
5610 ret = ftrace_startup(ops, 0);
5611
5612 mutex_unlock(&ftrace_lock);
5613
5614 return ret;
5615}
5616EXPORT_SYMBOL_GPL(register_ftrace_function);
5617
5618/**
5619 * unregister_ftrace_function - unregister a function for profiling.
5620 * @ops - ops structure that holds the function to unregister
5621 *
5622 * Unregister a function that was added to be called by ftrace profiling.
5623 */
5624int unregister_ftrace_function(struct ftrace_ops *ops)
5625{
5626 int ret;
5627
5628 mutex_lock(&ftrace_lock);
5629 ret = ftrace_shutdown(ops, 0);
5630 mutex_unlock(&ftrace_lock);
5631
5632 return ret;
5633}
5634EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5635
5636int
5637ftrace_enable_sysctl(struct ctl_table *table, int write,
5638 void __user *buffer, size_t *lenp,
5639 loff_t *ppos)
5640{
5641 int ret = -ENODEV;
5642
5643 mutex_lock(&ftrace_lock);
5644
5645 if (unlikely(ftrace_disabled))
5646 goto out;
5647
5648 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5649
5650 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5651 goto out;
5652
5653 last_ftrace_enabled = !!ftrace_enabled;
5654
5655 if (ftrace_enabled) {
5656
5657 /* we are starting ftrace again */
5658 if (ftrace_ops_list != &ftrace_list_end)
5659 update_ftrace_function();
5660
5661 ftrace_startup_sysctl();
5662
5663 } else {
5664 /* stopping ftrace calls (just send to ftrace_stub) */
5665 ftrace_trace_function = ftrace_stub;
5666
5667 ftrace_shutdown_sysctl();
5668 }
5669
5670 out:
5671 mutex_unlock(&ftrace_lock);
5672 return ret;
5673}
5674
5675#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5676
5677static struct ftrace_ops graph_ops = {
5678 .func = ftrace_stub,
5679 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5680 FTRACE_OPS_FL_INITIALIZED |
5681 FTRACE_OPS_FL_PID |
5682 FTRACE_OPS_FL_STUB,
5683#ifdef FTRACE_GRAPH_TRAMP_ADDR
5684 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5685 /* trampoline_size is only needed for dynamically allocated tramps */
5686#endif
5687 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5688};
5689
5690void ftrace_graph_sleep_time_control(bool enable)
5691{
5692 fgraph_sleep_time = enable;
5693}
5694
5695void ftrace_graph_graph_time_control(bool enable)
5696{
5697 fgraph_graph_time = enable;
5698}
5699
5700int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5701{
5702 return 0;
5703}
5704
5705/* The callbacks that hook a function */
5706trace_func_graph_ret_t ftrace_graph_return =
5707 (trace_func_graph_ret_t)ftrace_stub;
5708trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5709static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5710
5711/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5712static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5713{
5714 int i;
5715 int ret = 0;
5716 unsigned long flags;
5717 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5718 struct task_struct *g, *t;
5719
5720 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5721 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5722 * sizeof(struct ftrace_ret_stack),
5723 GFP_KERNEL);
5724 if (!ret_stack_list[i]) {
5725 start = 0;
5726 end = i;
5727 ret = -ENOMEM;
5728 goto free;
5729 }
5730 }
5731
5732 read_lock_irqsave(&tasklist_lock, flags);
5733 do_each_thread(g, t) {
5734 if (start == end) {
5735 ret = -EAGAIN;
5736 goto unlock;
5737 }
5738
5739 if (t->ret_stack == NULL) {
5740 atomic_set(&t->tracing_graph_pause, 0);
5741 atomic_set(&t->trace_overrun, 0);
5742 t->curr_ret_stack = -1;
5743 /* Make sure the tasks see the -1 first: */
5744 smp_wmb();
5745 t->ret_stack = ret_stack_list[start++];
5746 }
5747 } while_each_thread(g, t);
5748
5749unlock:
5750 read_unlock_irqrestore(&tasklist_lock, flags);
5751free:
5752 for (i = start; i < end; i++)
5753 kfree(ret_stack_list[i]);
5754 return ret;
5755}
5756
5757static void
5758ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5759 struct task_struct *prev, struct task_struct *next)
5760{
5761 unsigned long long timestamp;
5762 int index;
5763
5764 /*
5765 * Does the user want to count the time a function was asleep.
5766 * If so, do not update the time stamps.
5767 */
5768 if (fgraph_sleep_time)
5769 return;
5770
5771 timestamp = trace_clock_local();
5772
5773 prev->ftrace_timestamp = timestamp;
5774
5775 /* only process tasks that we timestamped */
5776 if (!next->ftrace_timestamp)
5777 return;
5778
5779 /*
5780 * Update all the counters in next to make up for the
5781 * time next was sleeping.
5782 */
5783 timestamp -= next->ftrace_timestamp;
5784
5785 for (index = next->curr_ret_stack; index >= 0; index--)
5786 next->ret_stack[index].calltime += timestamp;
5787}
5788
5789/* Allocate a return stack for each task */
5790static int start_graph_tracing(void)
5791{
5792 struct ftrace_ret_stack **ret_stack_list;
5793 int ret, cpu;
5794
5795 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5796 sizeof(struct ftrace_ret_stack *),
5797 GFP_KERNEL);
5798
5799 if (!ret_stack_list)
5800 return -ENOMEM;
5801
5802 /* The cpu_boot init_task->ret_stack will never be freed */
5803 for_each_online_cpu(cpu) {
5804 if (!idle_task(cpu)->ret_stack)
5805 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5806 }
5807
5808 do {
5809 ret = alloc_retstack_tasklist(ret_stack_list);
5810 } while (ret == -EAGAIN);
5811
5812 if (!ret) {
5813 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5814 if (ret)
5815 pr_info("ftrace_graph: Couldn't activate tracepoint"
5816 " probe to kernel_sched_switch\n");
5817 }
5818
5819 kfree(ret_stack_list);
5820 return ret;
5821}
5822
5823/*
5824 * Hibernation protection.
5825 * The state of the current task is too much unstable during
5826 * suspend/restore to disk. We want to protect against that.
5827 */
5828static int
5829ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5830 void *unused)
5831{
5832 switch (state) {
5833 case PM_HIBERNATION_PREPARE:
5834 pause_graph_tracing();
5835 break;
5836
5837 case PM_POST_HIBERNATION:
5838 unpause_graph_tracing();
5839 break;
5840 }
5841 return NOTIFY_DONE;
5842}
5843
5844static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5845{
5846 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5847 return 0;
5848 return __ftrace_graph_entry(trace);
5849}
5850
5851/*
5852 * The function graph tracer should only trace the functions defined
5853 * by set_ftrace_filter and set_ftrace_notrace. If another function
5854 * tracer ops is registered, the graph tracer requires testing the
5855 * function against the global ops, and not just trace any function
5856 * that any ftrace_ops registered.
5857 */
5858static void update_function_graph_func(void)
5859{
5860 struct ftrace_ops *op;
5861 bool do_test = false;
5862
5863 /*
5864 * The graph and global ops share the same set of functions
5865 * to test. If any other ops is on the list, then
5866 * the graph tracing needs to test if its the function
5867 * it should call.
5868 */
5869 do_for_each_ftrace_op(op, ftrace_ops_list) {
5870 if (op != &global_ops && op != &graph_ops &&
5871 op != &ftrace_list_end) {
5872 do_test = true;
5873 /* in double loop, break out with goto */
5874 goto out;
5875 }
5876 } while_for_each_ftrace_op(op);
5877 out:
5878 if (do_test)
5879 ftrace_graph_entry = ftrace_graph_entry_test;
5880 else
5881 ftrace_graph_entry = __ftrace_graph_entry;
5882}
5883
5884static struct notifier_block ftrace_suspend_notifier = {
5885 .notifier_call = ftrace_suspend_notifier_call,
5886};
5887
5888int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5889 trace_func_graph_ent_t entryfunc)
5890{
5891 int ret = 0;
5892
5893 mutex_lock(&ftrace_lock);
5894
5895 /* we currently allow only one tracer registered at a time */
5896 if (ftrace_graph_active) {
5897 ret = -EBUSY;
5898 goto out;
5899 }
5900
5901 register_pm_notifier(&ftrace_suspend_notifier);
5902
5903 ftrace_graph_active++;
5904 ret = start_graph_tracing();
5905 if (ret) {
5906 ftrace_graph_active--;
5907 goto out;
5908 }
5909
5910 ftrace_graph_return = retfunc;
5911
5912 /*
5913 * Update the indirect function to the entryfunc, and the
5914 * function that gets called to the entry_test first. Then
5915 * call the update fgraph entry function to determine if
5916 * the entryfunc should be called directly or not.
5917 */
5918 __ftrace_graph_entry = entryfunc;
5919 ftrace_graph_entry = ftrace_graph_entry_test;
5920 update_function_graph_func();
5921
5922 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5923out:
5924 mutex_unlock(&ftrace_lock);
5925 return ret;
5926}
5927
5928void unregister_ftrace_graph(void)
5929{
5930 mutex_lock(&ftrace_lock);
5931
5932 if (unlikely(!ftrace_graph_active))
5933 goto out;
5934
5935 ftrace_graph_active--;
5936 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5937 ftrace_graph_entry = ftrace_graph_entry_stub;
5938 __ftrace_graph_entry = ftrace_graph_entry_stub;
5939 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5940 unregister_pm_notifier(&ftrace_suspend_notifier);
5941 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5942
5943#ifdef CONFIG_DYNAMIC_FTRACE
5944 /*
5945 * Function graph does not allocate the trampoline, but
5946 * other global_ops do. We need to reset the ALLOC_TRAMP flag
5947 * if one was used.
5948 */
5949 global_ops.trampoline = save_global_trampoline;
5950 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
5951 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
5952#endif
5953
5954 out:
5955 mutex_unlock(&ftrace_lock);
5956}
5957
5958static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5959
5960static void
5961graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5962{
5963 atomic_set(&t->tracing_graph_pause, 0);
5964 atomic_set(&t->trace_overrun, 0);
5965 t->ftrace_timestamp = 0;
5966 /* make curr_ret_stack visible before we add the ret_stack */
5967 smp_wmb();
5968 t->ret_stack = ret_stack;
5969}
5970
5971/*
5972 * Allocate a return stack for the idle task. May be the first
5973 * time through, or it may be done by CPU hotplug online.
5974 */
5975void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5976{
5977 t->curr_ret_stack = -1;
5978 /*
5979 * The idle task has no parent, it either has its own
5980 * stack or no stack at all.
5981 */
5982 if (t->ret_stack)
5983 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5984
5985 if (ftrace_graph_active) {
5986 struct ftrace_ret_stack *ret_stack;
5987
5988 ret_stack = per_cpu(idle_ret_stack, cpu);
5989 if (!ret_stack) {
5990 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5991 * sizeof(struct ftrace_ret_stack),
5992 GFP_KERNEL);
5993 if (!ret_stack)
5994 return;
5995 per_cpu(idle_ret_stack, cpu) = ret_stack;
5996 }
5997 graph_init_task(t, ret_stack);
5998 }
5999}
6000
6001/* Allocate a return stack for newly created task */
6002void ftrace_graph_init_task(struct task_struct *t)
6003{
6004 /* Make sure we do not use the parent ret_stack */
6005 t->ret_stack = NULL;
6006 t->curr_ret_stack = -1;
6007
6008 if (ftrace_graph_active) {
6009 struct ftrace_ret_stack *ret_stack;
6010
6011 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6012 * sizeof(struct ftrace_ret_stack),
6013 GFP_KERNEL);
6014 if (!ret_stack)
6015 return;
6016 graph_init_task(t, ret_stack);
6017 }
6018}
6019
6020void ftrace_graph_exit_task(struct task_struct *t)
6021{
6022 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6023
6024 t->ret_stack = NULL;
6025 /* NULL must become visible to IRQs before we free it: */
6026 barrier();
6027
6028 kfree(ret_stack);
6029}
6030#endif