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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
92static bool ftrace_pids_enabled(struct ftrace_ops *ops)
93{
94 struct trace_array *tr;
95
96 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
97 return false;
98
99 tr = ops->private;
100
101 return tr->function_pids != NULL;
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 struct trace_array *tr = op->private;
183
184 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
185 return;
186
187 op->saved_func(ip, parent_ip, op, regs);
188}
189
190/**
191 * clear_ftrace_function - reset the ftrace function
192 *
193 * This NULLs the ftrace function and in essence stops
194 * tracing. There may be lag
195 */
196void clear_ftrace_function(void)
197{
198 ftrace_trace_function = ftrace_stub;
199}
200
201static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
202{
203 int cpu;
204
205 for_each_possible_cpu(cpu)
206 *per_cpu_ptr(ops->disabled, cpu) = 1;
207}
208
209static int per_cpu_ops_alloc(struct ftrace_ops *ops)
210{
211 int __percpu *disabled;
212
213 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
214 return -EINVAL;
215
216 disabled = alloc_percpu(int);
217 if (!disabled)
218 return -ENOMEM;
219
220 ops->disabled = disabled;
221 per_cpu_ops_disable_all(ops);
222 return 0;
223}
224
225static void ftrace_sync(struct work_struct *work)
226{
227 /*
228 * This function is just a stub to implement a hard force
229 * of synchronize_sched(). This requires synchronizing
230 * tasks even in userspace and idle.
231 *
232 * Yes, function tracing is rude.
233 */
234}
235
236static void ftrace_sync_ipi(void *data)
237{
238 /* Probably not needed, but do it anyway */
239 smp_rmb();
240}
241
242#ifdef CONFIG_FUNCTION_GRAPH_TRACER
243static void update_function_graph_func(void);
244
245/* Both enabled by default (can be cleared by function_graph tracer flags */
246static bool fgraph_sleep_time = true;
247static bool fgraph_graph_time = true;
248
249#else
250static inline void update_function_graph_func(void) { }
251#endif
252
253
254static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
255{
256 /*
257 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
258 * then it needs to call the list anyway.
259 */
260 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
261 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
262 return ftrace_ops_list_func;
263
264 return ftrace_ops_get_func(ops);
265}
266
267static void update_ftrace_function(void)
268{
269 ftrace_func_t func;
270
271 /*
272 * Prepare the ftrace_ops that the arch callback will use.
273 * If there's only one ftrace_ops registered, the ftrace_ops_list
274 * will point to the ops we want.
275 */
276 set_function_trace_op = ftrace_ops_list;
277
278 /* If there's no ftrace_ops registered, just call the stub function */
279 if (ftrace_ops_list == &ftrace_list_end) {
280 func = ftrace_stub;
281
282 /*
283 * If we are at the end of the list and this ops is
284 * recursion safe and not dynamic and the arch supports passing ops,
285 * then have the mcount trampoline call the function directly.
286 */
287 } else if (ftrace_ops_list->next == &ftrace_list_end) {
288 func = ftrace_ops_get_list_func(ftrace_ops_list);
289
290 } else {
291 /* Just use the default ftrace_ops */
292 set_function_trace_op = &ftrace_list_end;
293 func = ftrace_ops_list_func;
294 }
295
296 update_function_graph_func();
297
298 /* If there's no change, then do nothing more here */
299 if (ftrace_trace_function == func)
300 return;
301
302 /*
303 * If we are using the list function, it doesn't care
304 * about the function_trace_ops.
305 */
306 if (func == ftrace_ops_list_func) {
307 ftrace_trace_function = func;
308 /*
309 * Don't even bother setting function_trace_ops,
310 * it would be racy to do so anyway.
311 */
312 return;
313 }
314
315#ifndef CONFIG_DYNAMIC_FTRACE
316 /*
317 * For static tracing, we need to be a bit more careful.
318 * The function change takes affect immediately. Thus,
319 * we need to coorditate the setting of the function_trace_ops
320 * with the setting of the ftrace_trace_function.
321 *
322 * Set the function to the list ops, which will call the
323 * function we want, albeit indirectly, but it handles the
324 * ftrace_ops and doesn't depend on function_trace_op.
325 */
326 ftrace_trace_function = ftrace_ops_list_func;
327 /*
328 * Make sure all CPUs see this. Yes this is slow, but static
329 * tracing is slow and nasty to have enabled.
330 */
331 schedule_on_each_cpu(ftrace_sync);
332 /* Now all cpus are using the list ops. */
333 function_trace_op = set_function_trace_op;
334 /* Make sure the function_trace_op is visible on all CPUs */
335 smp_wmb();
336 /* Nasty way to force a rmb on all cpus */
337 smp_call_function(ftrace_sync_ipi, NULL, 1);
338 /* OK, we are all set to update the ftrace_trace_function now! */
339#endif /* !CONFIG_DYNAMIC_FTRACE */
340
341 ftrace_trace_function = func;
342}
343
344int using_ftrace_ops_list_func(void)
345{
346 return ftrace_trace_function == ftrace_ops_list_func;
347}
348
349static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
350{
351 ops->next = *list;
352 /*
353 * We are entering ops into the list but another
354 * CPU might be walking that list. We need to make sure
355 * the ops->next pointer is valid before another CPU sees
356 * the ops pointer included into the list.
357 */
358 rcu_assign_pointer(*list, ops);
359}
360
361static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
362{
363 struct ftrace_ops **p;
364
365 /*
366 * If we are removing the last function, then simply point
367 * to the ftrace_stub.
368 */
369 if (*list == ops && ops->next == &ftrace_list_end) {
370 *list = &ftrace_list_end;
371 return 0;
372 }
373
374 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
375 if (*p == ops)
376 break;
377
378 if (*p != ops)
379 return -1;
380
381 *p = (*p)->next;
382 return 0;
383}
384
385static void ftrace_update_trampoline(struct ftrace_ops *ops);
386
387static int __register_ftrace_function(struct ftrace_ops *ops)
388{
389 if (ops->flags & FTRACE_OPS_FL_DELETED)
390 return -EINVAL;
391
392 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
393 return -EBUSY;
394
395#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
396 /*
397 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
398 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
399 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
400 */
401 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
402 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
403 return -EINVAL;
404
405 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
406 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
407#endif
408
409 if (!core_kernel_data((unsigned long)ops))
410 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
411
412 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
413 if (per_cpu_ops_alloc(ops))
414 return -ENOMEM;
415 }
416
417 add_ftrace_ops(&ftrace_ops_list, ops);
418
419 /* Always save the function, and reset at unregistering */
420 ops->saved_func = ops->func;
421
422 if (ftrace_pids_enabled(ops))
423 ops->func = ftrace_pid_func;
424
425 ftrace_update_trampoline(ops);
426
427 if (ftrace_enabled)
428 update_ftrace_function();
429
430 return 0;
431}
432
433static int __unregister_ftrace_function(struct ftrace_ops *ops)
434{
435 int ret;
436
437 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
438 return -EBUSY;
439
440 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
441
442 if (ret < 0)
443 return ret;
444
445 if (ftrace_enabled)
446 update_ftrace_function();
447
448 ops->func = ops->saved_func;
449
450 return 0;
451}
452
453static void ftrace_update_pid_func(void)
454{
455 struct ftrace_ops *op;
456
457 /* Only do something if we are tracing something */
458 if (ftrace_trace_function == ftrace_stub)
459 return;
460
461 do_for_each_ftrace_op(op, ftrace_ops_list) {
462 if (op->flags & FTRACE_OPS_FL_PID) {
463 op->func = ftrace_pids_enabled(op) ?
464 ftrace_pid_func : op->saved_func;
465 ftrace_update_trampoline(op);
466 }
467 } while_for_each_ftrace_op(op);
468
469 update_ftrace_function();
470}
471
472#ifdef CONFIG_FUNCTION_PROFILER
473struct ftrace_profile {
474 struct hlist_node node;
475 unsigned long ip;
476 unsigned long counter;
477#ifdef CONFIG_FUNCTION_GRAPH_TRACER
478 unsigned long long time;
479 unsigned long long time_squared;
480#endif
481};
482
483struct ftrace_profile_page {
484 struct ftrace_profile_page *next;
485 unsigned long index;
486 struct ftrace_profile records[];
487};
488
489struct ftrace_profile_stat {
490 atomic_t disabled;
491 struct hlist_head *hash;
492 struct ftrace_profile_page *pages;
493 struct ftrace_profile_page *start;
494 struct tracer_stat stat;
495};
496
497#define PROFILE_RECORDS_SIZE \
498 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
499
500#define PROFILES_PER_PAGE \
501 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
502
503static int ftrace_profile_enabled __read_mostly;
504
505/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
506static DEFINE_MUTEX(ftrace_profile_lock);
507
508static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
509
510#define FTRACE_PROFILE_HASH_BITS 10
511#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
512
513static void *
514function_stat_next(void *v, int idx)
515{
516 struct ftrace_profile *rec = v;
517 struct ftrace_profile_page *pg;
518
519 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
520
521 again:
522 if (idx != 0)
523 rec++;
524
525 if ((void *)rec >= (void *)&pg->records[pg->index]) {
526 pg = pg->next;
527 if (!pg)
528 return NULL;
529 rec = &pg->records[0];
530 if (!rec->counter)
531 goto again;
532 }
533
534 return rec;
535}
536
537static void *function_stat_start(struct tracer_stat *trace)
538{
539 struct ftrace_profile_stat *stat =
540 container_of(trace, struct ftrace_profile_stat, stat);
541
542 if (!stat || !stat->start)
543 return NULL;
544
545 return function_stat_next(&stat->start->records[0], 0);
546}
547
548#ifdef CONFIG_FUNCTION_GRAPH_TRACER
549/* function graph compares on total time */
550static int function_stat_cmp(void *p1, void *p2)
551{
552 struct ftrace_profile *a = p1;
553 struct ftrace_profile *b = p2;
554
555 if (a->time < b->time)
556 return -1;
557 if (a->time > b->time)
558 return 1;
559 else
560 return 0;
561}
562#else
563/* not function graph compares against hits */
564static int function_stat_cmp(void *p1, void *p2)
565{
566 struct ftrace_profile *a = p1;
567 struct ftrace_profile *b = p2;
568
569 if (a->counter < b->counter)
570 return -1;
571 if (a->counter > b->counter)
572 return 1;
573 else
574 return 0;
575}
576#endif
577
578static int function_stat_headers(struct seq_file *m)
579{
580#ifdef CONFIG_FUNCTION_GRAPH_TRACER
581 seq_puts(m, " Function "
582 "Hit Time Avg s^2\n"
583 " -------- "
584 "--- ---- --- ---\n");
585#else
586 seq_puts(m, " Function Hit\n"
587 " -------- ---\n");
588#endif
589 return 0;
590}
591
592static int function_stat_show(struct seq_file *m, void *v)
593{
594 struct ftrace_profile *rec = v;
595 char str[KSYM_SYMBOL_LEN];
596 int ret = 0;
597#ifdef CONFIG_FUNCTION_GRAPH_TRACER
598 static struct trace_seq s;
599 unsigned long long avg;
600 unsigned long long stddev;
601#endif
602 mutex_lock(&ftrace_profile_lock);
603
604 /* we raced with function_profile_reset() */
605 if (unlikely(rec->counter == 0)) {
606 ret = -EBUSY;
607 goto out;
608 }
609
610#ifdef CONFIG_FUNCTION_GRAPH_TRACER
611 avg = rec->time;
612 do_div(avg, rec->counter);
613 if (tracing_thresh && (avg < tracing_thresh))
614 goto out;
615#endif
616
617 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
618 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
619
620#ifdef CONFIG_FUNCTION_GRAPH_TRACER
621 seq_puts(m, " ");
622
623 /* Sample standard deviation (s^2) */
624 if (rec->counter <= 1)
625 stddev = 0;
626 else {
627 /*
628 * Apply Welford's method:
629 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
630 */
631 stddev = rec->counter * rec->time_squared -
632 rec->time * rec->time;
633
634 /*
635 * Divide only 1000 for ns^2 -> us^2 conversion.
636 * trace_print_graph_duration will divide 1000 again.
637 */
638 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
639 }
640
641 trace_seq_init(&s);
642 trace_print_graph_duration(rec->time, &s);
643 trace_seq_puts(&s, " ");
644 trace_print_graph_duration(avg, &s);
645 trace_seq_puts(&s, " ");
646 trace_print_graph_duration(stddev, &s);
647 trace_print_seq(m, &s);
648#endif
649 seq_putc(m, '\n');
650out:
651 mutex_unlock(&ftrace_profile_lock);
652
653 return ret;
654}
655
656static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
657{
658 struct ftrace_profile_page *pg;
659
660 pg = stat->pages = stat->start;
661
662 while (pg) {
663 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
664 pg->index = 0;
665 pg = pg->next;
666 }
667
668 memset(stat->hash, 0,
669 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
670}
671
672int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
673{
674 struct ftrace_profile_page *pg;
675 int functions;
676 int pages;
677 int i;
678
679 /* If we already allocated, do nothing */
680 if (stat->pages)
681 return 0;
682
683 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
684 if (!stat->pages)
685 return -ENOMEM;
686
687#ifdef CONFIG_DYNAMIC_FTRACE
688 functions = ftrace_update_tot_cnt;
689#else
690 /*
691 * We do not know the number of functions that exist because
692 * dynamic tracing is what counts them. With past experience
693 * we have around 20K functions. That should be more than enough.
694 * It is highly unlikely we will execute every function in
695 * the kernel.
696 */
697 functions = 20000;
698#endif
699
700 pg = stat->start = stat->pages;
701
702 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
703
704 for (i = 1; i < pages; i++) {
705 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
706 if (!pg->next)
707 goto out_free;
708 pg = pg->next;
709 }
710
711 return 0;
712
713 out_free:
714 pg = stat->start;
715 while (pg) {
716 unsigned long tmp = (unsigned long)pg;
717
718 pg = pg->next;
719 free_page(tmp);
720 }
721
722 stat->pages = NULL;
723 stat->start = NULL;
724
725 return -ENOMEM;
726}
727
728static int ftrace_profile_init_cpu(int cpu)
729{
730 struct ftrace_profile_stat *stat;
731 int size;
732
733 stat = &per_cpu(ftrace_profile_stats, cpu);
734
735 if (stat->hash) {
736 /* If the profile is already created, simply reset it */
737 ftrace_profile_reset(stat);
738 return 0;
739 }
740
741 /*
742 * We are profiling all functions, but usually only a few thousand
743 * functions are hit. We'll make a hash of 1024 items.
744 */
745 size = FTRACE_PROFILE_HASH_SIZE;
746
747 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
748
749 if (!stat->hash)
750 return -ENOMEM;
751
752 /* Preallocate the function profiling pages */
753 if (ftrace_profile_pages_init(stat) < 0) {
754 kfree(stat->hash);
755 stat->hash = NULL;
756 return -ENOMEM;
757 }
758
759 return 0;
760}
761
762static int ftrace_profile_init(void)
763{
764 int cpu;
765 int ret = 0;
766
767 for_each_possible_cpu(cpu) {
768 ret = ftrace_profile_init_cpu(cpu);
769 if (ret)
770 break;
771 }
772
773 return ret;
774}
775
776/* interrupts must be disabled */
777static struct ftrace_profile *
778ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
779{
780 struct ftrace_profile *rec;
781 struct hlist_head *hhd;
782 unsigned long key;
783
784 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
785 hhd = &stat->hash[key];
786
787 if (hlist_empty(hhd))
788 return NULL;
789
790 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
791 if (rec->ip == ip)
792 return rec;
793 }
794
795 return NULL;
796}
797
798static void ftrace_add_profile(struct ftrace_profile_stat *stat,
799 struct ftrace_profile *rec)
800{
801 unsigned long key;
802
803 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
804 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
805}
806
807/*
808 * The memory is already allocated, this simply finds a new record to use.
809 */
810static struct ftrace_profile *
811ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
812{
813 struct ftrace_profile *rec = NULL;
814
815 /* prevent recursion (from NMIs) */
816 if (atomic_inc_return(&stat->disabled) != 1)
817 goto out;
818
819 /*
820 * Try to find the function again since an NMI
821 * could have added it
822 */
823 rec = ftrace_find_profiled_func(stat, ip);
824 if (rec)
825 goto out;
826
827 if (stat->pages->index == PROFILES_PER_PAGE) {
828 if (!stat->pages->next)
829 goto out;
830 stat->pages = stat->pages->next;
831 }
832
833 rec = &stat->pages->records[stat->pages->index++];
834 rec->ip = ip;
835 ftrace_add_profile(stat, rec);
836
837 out:
838 atomic_dec(&stat->disabled);
839
840 return rec;
841}
842
843static void
844function_profile_call(unsigned long ip, unsigned long parent_ip,
845 struct ftrace_ops *ops, struct pt_regs *regs)
846{
847 struct ftrace_profile_stat *stat;
848 struct ftrace_profile *rec;
849 unsigned long flags;
850
851 if (!ftrace_profile_enabled)
852 return;
853
854 local_irq_save(flags);
855
856 stat = this_cpu_ptr(&ftrace_profile_stats);
857 if (!stat->hash || !ftrace_profile_enabled)
858 goto out;
859
860 rec = ftrace_find_profiled_func(stat, ip);
861 if (!rec) {
862 rec = ftrace_profile_alloc(stat, ip);
863 if (!rec)
864 goto out;
865 }
866
867 rec->counter++;
868 out:
869 local_irq_restore(flags);
870}
871
872#ifdef CONFIG_FUNCTION_GRAPH_TRACER
873static int profile_graph_entry(struct ftrace_graph_ent *trace)
874{
875 int index = trace->depth;
876
877 function_profile_call(trace->func, 0, NULL, NULL);
878
879 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
880 current->ret_stack[index].subtime = 0;
881
882 return 1;
883}
884
885static void profile_graph_return(struct ftrace_graph_ret *trace)
886{
887 struct ftrace_profile_stat *stat;
888 unsigned long long calltime;
889 struct ftrace_profile *rec;
890 unsigned long flags;
891
892 local_irq_save(flags);
893 stat = this_cpu_ptr(&ftrace_profile_stats);
894 if (!stat->hash || !ftrace_profile_enabled)
895 goto out;
896
897 /* If the calltime was zero'd ignore it */
898 if (!trace->calltime)
899 goto out;
900
901 calltime = trace->rettime - trace->calltime;
902
903 if (!fgraph_graph_time) {
904 int index;
905
906 index = trace->depth;
907
908 /* Append this call time to the parent time to subtract */
909 if (index)
910 current->ret_stack[index - 1].subtime += calltime;
911
912 if (current->ret_stack[index].subtime < calltime)
913 calltime -= current->ret_stack[index].subtime;
914 else
915 calltime = 0;
916 }
917
918 rec = ftrace_find_profiled_func(stat, trace->func);
919 if (rec) {
920 rec->time += calltime;
921 rec->time_squared += calltime * calltime;
922 }
923
924 out:
925 local_irq_restore(flags);
926}
927
928static int register_ftrace_profiler(void)
929{
930 return register_ftrace_graph(&profile_graph_return,
931 &profile_graph_entry);
932}
933
934static void unregister_ftrace_profiler(void)
935{
936 unregister_ftrace_graph();
937}
938#else
939static struct ftrace_ops ftrace_profile_ops __read_mostly = {
940 .func = function_profile_call,
941 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
942 INIT_OPS_HASH(ftrace_profile_ops)
943};
944
945static int register_ftrace_profiler(void)
946{
947 return register_ftrace_function(&ftrace_profile_ops);
948}
949
950static void unregister_ftrace_profiler(void)
951{
952 unregister_ftrace_function(&ftrace_profile_ops);
953}
954#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
955
956static ssize_t
957ftrace_profile_write(struct file *filp, const char __user *ubuf,
958 size_t cnt, loff_t *ppos)
959{
960 unsigned long val;
961 int ret;
962
963 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
964 if (ret)
965 return ret;
966
967 val = !!val;
968
969 mutex_lock(&ftrace_profile_lock);
970 if (ftrace_profile_enabled ^ val) {
971 if (val) {
972 ret = ftrace_profile_init();
973 if (ret < 0) {
974 cnt = ret;
975 goto out;
976 }
977
978 ret = register_ftrace_profiler();
979 if (ret < 0) {
980 cnt = ret;
981 goto out;
982 }
983 ftrace_profile_enabled = 1;
984 } else {
985 ftrace_profile_enabled = 0;
986 /*
987 * unregister_ftrace_profiler calls stop_machine
988 * so this acts like an synchronize_sched.
989 */
990 unregister_ftrace_profiler();
991 }
992 }
993 out:
994 mutex_unlock(&ftrace_profile_lock);
995
996 *ppos += cnt;
997
998 return cnt;
999}
1000
1001static ssize_t
1002ftrace_profile_read(struct file *filp, char __user *ubuf,
1003 size_t cnt, loff_t *ppos)
1004{
1005 char buf[64]; /* big enough to hold a number */
1006 int r;
1007
1008 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1009 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1010}
1011
1012static const struct file_operations ftrace_profile_fops = {
1013 .open = tracing_open_generic,
1014 .read = ftrace_profile_read,
1015 .write = ftrace_profile_write,
1016 .llseek = default_llseek,
1017};
1018
1019/* used to initialize the real stat files */
1020static struct tracer_stat function_stats __initdata = {
1021 .name = "functions",
1022 .stat_start = function_stat_start,
1023 .stat_next = function_stat_next,
1024 .stat_cmp = function_stat_cmp,
1025 .stat_headers = function_stat_headers,
1026 .stat_show = function_stat_show
1027};
1028
1029static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1030{
1031 struct ftrace_profile_stat *stat;
1032 struct dentry *entry;
1033 char *name;
1034 int ret;
1035 int cpu;
1036
1037 for_each_possible_cpu(cpu) {
1038 stat = &per_cpu(ftrace_profile_stats, cpu);
1039
1040 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1041 if (!name) {
1042 /*
1043 * The files created are permanent, if something happens
1044 * we still do not free memory.
1045 */
1046 WARN(1,
1047 "Could not allocate stat file for cpu %d\n",
1048 cpu);
1049 return;
1050 }
1051 stat->stat = function_stats;
1052 stat->stat.name = name;
1053 ret = register_stat_tracer(&stat->stat);
1054 if (ret) {
1055 WARN(1,
1056 "Could not register function stat for cpu %d\n",
1057 cpu);
1058 kfree(name);
1059 return;
1060 }
1061 }
1062
1063 entry = tracefs_create_file("function_profile_enabled", 0644,
1064 d_tracer, NULL, &ftrace_profile_fops);
1065 if (!entry)
1066 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1067}
1068
1069#else /* CONFIG_FUNCTION_PROFILER */
1070static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1071{
1072}
1073#endif /* CONFIG_FUNCTION_PROFILER */
1074
1075static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1076
1077#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1078static int ftrace_graph_active;
1079#else
1080# define ftrace_graph_active 0
1081#endif
1082
1083#ifdef CONFIG_DYNAMIC_FTRACE
1084
1085static struct ftrace_ops *removed_ops;
1086
1087/*
1088 * Set when doing a global update, like enabling all recs or disabling them.
1089 * It is not set when just updating a single ftrace_ops.
1090 */
1091static bool update_all_ops;
1092
1093#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1094# error Dynamic ftrace depends on MCOUNT_RECORD
1095#endif
1096
1097static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1098
1099struct ftrace_func_probe {
1100 struct hlist_node node;
1101 struct ftrace_probe_ops *ops;
1102 unsigned long flags;
1103 unsigned long ip;
1104 void *data;
1105 struct list_head free_list;
1106};
1107
1108struct ftrace_func_entry {
1109 struct hlist_node hlist;
1110 unsigned long ip;
1111};
1112
1113struct ftrace_hash {
1114 unsigned long size_bits;
1115 struct hlist_head *buckets;
1116 unsigned long count;
1117 struct rcu_head rcu;
1118};
1119
1120/*
1121 * We make these constant because no one should touch them,
1122 * but they are used as the default "empty hash", to avoid allocating
1123 * it all the time. These are in a read only section such that if
1124 * anyone does try to modify it, it will cause an exception.
1125 */
1126static const struct hlist_head empty_buckets[1];
1127static const struct ftrace_hash empty_hash = {
1128 .buckets = (struct hlist_head *)empty_buckets,
1129};
1130#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1131
1132static struct ftrace_ops global_ops = {
1133 .func = ftrace_stub,
1134 .local_hash.notrace_hash = EMPTY_HASH,
1135 .local_hash.filter_hash = EMPTY_HASH,
1136 INIT_OPS_HASH(global_ops)
1137 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1138 FTRACE_OPS_FL_INITIALIZED |
1139 FTRACE_OPS_FL_PID,
1140};
1141
1142/*
1143 * This is used by __kernel_text_address() to return true if the
1144 * address is on a dynamically allocated trampoline that would
1145 * not return true for either core_kernel_text() or
1146 * is_module_text_address().
1147 */
1148bool is_ftrace_trampoline(unsigned long addr)
1149{
1150 struct ftrace_ops *op;
1151 bool ret = false;
1152
1153 /*
1154 * Some of the ops may be dynamically allocated,
1155 * they are freed after a synchronize_sched().
1156 */
1157 preempt_disable_notrace();
1158
1159 do_for_each_ftrace_op(op, ftrace_ops_list) {
1160 /*
1161 * This is to check for dynamically allocated trampolines.
1162 * Trampolines that are in kernel text will have
1163 * core_kernel_text() return true.
1164 */
1165 if (op->trampoline && op->trampoline_size)
1166 if (addr >= op->trampoline &&
1167 addr < op->trampoline + op->trampoline_size) {
1168 ret = true;
1169 goto out;
1170 }
1171 } while_for_each_ftrace_op(op);
1172
1173 out:
1174 preempt_enable_notrace();
1175
1176 return ret;
1177}
1178
1179struct ftrace_page {
1180 struct ftrace_page *next;
1181 struct dyn_ftrace *records;
1182 int index;
1183 int size;
1184};
1185
1186#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1187#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1188
1189/* estimate from running different kernels */
1190#define NR_TO_INIT 10000
1191
1192static struct ftrace_page *ftrace_pages_start;
1193static struct ftrace_page *ftrace_pages;
1194
1195static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1196{
1197 return !hash || !hash->count;
1198}
1199
1200static struct ftrace_func_entry *
1201ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1202{
1203 unsigned long key;
1204 struct ftrace_func_entry *entry;
1205 struct hlist_head *hhd;
1206
1207 if (ftrace_hash_empty(hash))
1208 return NULL;
1209
1210 if (hash->size_bits > 0)
1211 key = hash_long(ip, hash->size_bits);
1212 else
1213 key = 0;
1214
1215 hhd = &hash->buckets[key];
1216
1217 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1218 if (entry->ip == ip)
1219 return entry;
1220 }
1221 return NULL;
1222}
1223
1224static void __add_hash_entry(struct ftrace_hash *hash,
1225 struct ftrace_func_entry *entry)
1226{
1227 struct hlist_head *hhd;
1228 unsigned long key;
1229
1230 if (hash->size_bits)
1231 key = hash_long(entry->ip, hash->size_bits);
1232 else
1233 key = 0;
1234
1235 hhd = &hash->buckets[key];
1236 hlist_add_head(&entry->hlist, hhd);
1237 hash->count++;
1238}
1239
1240static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1241{
1242 struct ftrace_func_entry *entry;
1243
1244 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1245 if (!entry)
1246 return -ENOMEM;
1247
1248 entry->ip = ip;
1249 __add_hash_entry(hash, entry);
1250
1251 return 0;
1252}
1253
1254static void
1255free_hash_entry(struct ftrace_hash *hash,
1256 struct ftrace_func_entry *entry)
1257{
1258 hlist_del(&entry->hlist);
1259 kfree(entry);
1260 hash->count--;
1261}
1262
1263static void
1264remove_hash_entry(struct ftrace_hash *hash,
1265 struct ftrace_func_entry *entry)
1266{
1267 hlist_del(&entry->hlist);
1268 hash->count--;
1269}
1270
1271static void ftrace_hash_clear(struct ftrace_hash *hash)
1272{
1273 struct hlist_head *hhd;
1274 struct hlist_node *tn;
1275 struct ftrace_func_entry *entry;
1276 int size = 1 << hash->size_bits;
1277 int i;
1278
1279 if (!hash->count)
1280 return;
1281
1282 for (i = 0; i < size; i++) {
1283 hhd = &hash->buckets[i];
1284 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1285 free_hash_entry(hash, entry);
1286 }
1287 FTRACE_WARN_ON(hash->count);
1288}
1289
1290static void free_ftrace_hash(struct ftrace_hash *hash)
1291{
1292 if (!hash || hash == EMPTY_HASH)
1293 return;
1294 ftrace_hash_clear(hash);
1295 kfree(hash->buckets);
1296 kfree(hash);
1297}
1298
1299static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1300{
1301 struct ftrace_hash *hash;
1302
1303 hash = container_of(rcu, struct ftrace_hash, rcu);
1304 free_ftrace_hash(hash);
1305}
1306
1307static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1308{
1309 if (!hash || hash == EMPTY_HASH)
1310 return;
1311 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1312}
1313
1314void ftrace_free_filter(struct ftrace_ops *ops)
1315{
1316 ftrace_ops_init(ops);
1317 free_ftrace_hash(ops->func_hash->filter_hash);
1318 free_ftrace_hash(ops->func_hash->notrace_hash);
1319}
1320
1321static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1322{
1323 struct ftrace_hash *hash;
1324 int size;
1325
1326 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1327 if (!hash)
1328 return NULL;
1329
1330 size = 1 << size_bits;
1331 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1332
1333 if (!hash->buckets) {
1334 kfree(hash);
1335 return NULL;
1336 }
1337
1338 hash->size_bits = size_bits;
1339
1340 return hash;
1341}
1342
1343static struct ftrace_hash *
1344alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1345{
1346 struct ftrace_func_entry *entry;
1347 struct ftrace_hash *new_hash;
1348 int size;
1349 int ret;
1350 int i;
1351
1352 new_hash = alloc_ftrace_hash(size_bits);
1353 if (!new_hash)
1354 return NULL;
1355
1356 /* Empty hash? */
1357 if (ftrace_hash_empty(hash))
1358 return new_hash;
1359
1360 size = 1 << hash->size_bits;
1361 for (i = 0; i < size; i++) {
1362 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1363 ret = add_hash_entry(new_hash, entry->ip);
1364 if (ret < 0)
1365 goto free_hash;
1366 }
1367 }
1368
1369 FTRACE_WARN_ON(new_hash->count != hash->count);
1370
1371 return new_hash;
1372
1373 free_hash:
1374 free_ftrace_hash(new_hash);
1375 return NULL;
1376}
1377
1378static void
1379ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1380static void
1381ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1382
1383static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1384 struct ftrace_hash *new_hash);
1385
1386static int
1387ftrace_hash_move(struct ftrace_ops *ops, int enable,
1388 struct ftrace_hash **dst, struct ftrace_hash *src)
1389{
1390 struct ftrace_func_entry *entry;
1391 struct hlist_node *tn;
1392 struct hlist_head *hhd;
1393 struct ftrace_hash *new_hash;
1394 int size = src->count;
1395 int bits = 0;
1396 int ret;
1397 int i;
1398
1399 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1400 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1401 return -EINVAL;
1402
1403 /*
1404 * If the new source is empty, just free dst and assign it
1405 * the empty_hash.
1406 */
1407 if (!src->count) {
1408 new_hash = EMPTY_HASH;
1409 goto update;
1410 }
1411
1412 /*
1413 * Make the hash size about 1/2 the # found
1414 */
1415 for (size /= 2; size; size >>= 1)
1416 bits++;
1417
1418 /* Don't allocate too much */
1419 if (bits > FTRACE_HASH_MAX_BITS)
1420 bits = FTRACE_HASH_MAX_BITS;
1421
1422 new_hash = alloc_ftrace_hash(bits);
1423 if (!new_hash)
1424 return -ENOMEM;
1425
1426 size = 1 << src->size_bits;
1427 for (i = 0; i < size; i++) {
1428 hhd = &src->buckets[i];
1429 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1430 remove_hash_entry(src, entry);
1431 __add_hash_entry(new_hash, entry);
1432 }
1433 }
1434
1435update:
1436 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1437 if (enable) {
1438 /* IPMODIFY should be updated only when filter_hash updating */
1439 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1440 if (ret < 0) {
1441 free_ftrace_hash(new_hash);
1442 return ret;
1443 }
1444 }
1445
1446 /*
1447 * Remove the current set, update the hash and add
1448 * them back.
1449 */
1450 ftrace_hash_rec_disable_modify(ops, enable);
1451
1452 rcu_assign_pointer(*dst, new_hash);
1453
1454 ftrace_hash_rec_enable_modify(ops, enable);
1455
1456 return 0;
1457}
1458
1459static bool hash_contains_ip(unsigned long ip,
1460 struct ftrace_ops_hash *hash)
1461{
1462 /*
1463 * The function record is a match if it exists in the filter
1464 * hash and not in the notrace hash. Note, an emty hash is
1465 * considered a match for the filter hash, but an empty
1466 * notrace hash is considered not in the notrace hash.
1467 */
1468 return (ftrace_hash_empty(hash->filter_hash) ||
1469 ftrace_lookup_ip(hash->filter_hash, ip)) &&
1470 (ftrace_hash_empty(hash->notrace_hash) ||
1471 !ftrace_lookup_ip(hash->notrace_hash, ip));
1472}
1473
1474/*
1475 * Test the hashes for this ops to see if we want to call
1476 * the ops->func or not.
1477 *
1478 * It's a match if the ip is in the ops->filter_hash or
1479 * the filter_hash does not exist or is empty,
1480 * AND
1481 * the ip is not in the ops->notrace_hash.
1482 *
1483 * This needs to be called with preemption disabled as
1484 * the hashes are freed with call_rcu_sched().
1485 */
1486static int
1487ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1488{
1489 struct ftrace_ops_hash hash;
1490 int ret;
1491
1492#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1493 /*
1494 * There's a small race when adding ops that the ftrace handler
1495 * that wants regs, may be called without them. We can not
1496 * allow that handler to be called if regs is NULL.
1497 */
1498 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1499 return 0;
1500#endif
1501
1502 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1503 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1504
1505 if (hash_contains_ip(ip, &hash))
1506 ret = 1;
1507 else
1508 ret = 0;
1509
1510 return ret;
1511}
1512
1513/*
1514 * This is a double for. Do not use 'break' to break out of the loop,
1515 * you must use a goto.
1516 */
1517#define do_for_each_ftrace_rec(pg, rec) \
1518 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1519 int _____i; \
1520 for (_____i = 0; _____i < pg->index; _____i++) { \
1521 rec = &pg->records[_____i];
1522
1523#define while_for_each_ftrace_rec() \
1524 } \
1525 }
1526
1527
1528static int ftrace_cmp_recs(const void *a, const void *b)
1529{
1530 const struct dyn_ftrace *key = a;
1531 const struct dyn_ftrace *rec = b;
1532
1533 if (key->flags < rec->ip)
1534 return -1;
1535 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1536 return 1;
1537 return 0;
1538}
1539
1540/**
1541 * ftrace_location_range - return the first address of a traced location
1542 * if it touches the given ip range
1543 * @start: start of range to search.
1544 * @end: end of range to search (inclusive). @end points to the last byte
1545 * to check.
1546 *
1547 * Returns rec->ip if the related ftrace location is a least partly within
1548 * the given address range. That is, the first address of the instruction
1549 * that is either a NOP or call to the function tracer. It checks the ftrace
1550 * internal tables to determine if the address belongs or not.
1551 */
1552unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1553{
1554 struct ftrace_page *pg;
1555 struct dyn_ftrace *rec;
1556 struct dyn_ftrace key;
1557
1558 key.ip = start;
1559 key.flags = end; /* overload flags, as it is unsigned long */
1560
1561 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1562 if (end < pg->records[0].ip ||
1563 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1564 continue;
1565 rec = bsearch(&key, pg->records, pg->index,
1566 sizeof(struct dyn_ftrace),
1567 ftrace_cmp_recs);
1568 if (rec)
1569 return rec->ip;
1570 }
1571
1572 return 0;
1573}
1574
1575/**
1576 * ftrace_location - return true if the ip giving is a traced location
1577 * @ip: the instruction pointer to check
1578 *
1579 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1580 * That is, the instruction that is either a NOP or call to
1581 * the function tracer. It checks the ftrace internal tables to
1582 * determine if the address belongs or not.
1583 */
1584unsigned long ftrace_location(unsigned long ip)
1585{
1586 return ftrace_location_range(ip, ip);
1587}
1588
1589/**
1590 * ftrace_text_reserved - return true if range contains an ftrace location
1591 * @start: start of range to search
1592 * @end: end of range to search (inclusive). @end points to the last byte to check.
1593 *
1594 * Returns 1 if @start and @end contains a ftrace location.
1595 * That is, the instruction that is either a NOP or call to
1596 * the function tracer. It checks the ftrace internal tables to
1597 * determine if the address belongs or not.
1598 */
1599int ftrace_text_reserved(const void *start, const void *end)
1600{
1601 unsigned long ret;
1602
1603 ret = ftrace_location_range((unsigned long)start,
1604 (unsigned long)end);
1605
1606 return (int)!!ret;
1607}
1608
1609/* Test if ops registered to this rec needs regs */
1610static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1611{
1612 struct ftrace_ops *ops;
1613 bool keep_regs = false;
1614
1615 for (ops = ftrace_ops_list;
1616 ops != &ftrace_list_end; ops = ops->next) {
1617 /* pass rec in as regs to have non-NULL val */
1618 if (ftrace_ops_test(ops, rec->ip, rec)) {
1619 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1620 keep_regs = true;
1621 break;
1622 }
1623 }
1624 }
1625
1626 return keep_regs;
1627}
1628
1629static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1630 int filter_hash,
1631 bool inc)
1632{
1633 struct ftrace_hash *hash;
1634 struct ftrace_hash *other_hash;
1635 struct ftrace_page *pg;
1636 struct dyn_ftrace *rec;
1637 bool update = false;
1638 int count = 0;
1639 int all = 0;
1640
1641 /* Only update if the ops has been registered */
1642 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1643 return false;
1644
1645 /*
1646 * In the filter_hash case:
1647 * If the count is zero, we update all records.
1648 * Otherwise we just update the items in the hash.
1649 *
1650 * In the notrace_hash case:
1651 * We enable the update in the hash.
1652 * As disabling notrace means enabling the tracing,
1653 * and enabling notrace means disabling, the inc variable
1654 * gets inversed.
1655 */
1656 if (filter_hash) {
1657 hash = ops->func_hash->filter_hash;
1658 other_hash = ops->func_hash->notrace_hash;
1659 if (ftrace_hash_empty(hash))
1660 all = 1;
1661 } else {
1662 inc = !inc;
1663 hash = ops->func_hash->notrace_hash;
1664 other_hash = ops->func_hash->filter_hash;
1665 /*
1666 * If the notrace hash has no items,
1667 * then there's nothing to do.
1668 */
1669 if (ftrace_hash_empty(hash))
1670 return false;
1671 }
1672
1673 do_for_each_ftrace_rec(pg, rec) {
1674 int in_other_hash = 0;
1675 int in_hash = 0;
1676 int match = 0;
1677
1678 if (rec->flags & FTRACE_FL_DISABLED)
1679 continue;
1680
1681 if (all) {
1682 /*
1683 * Only the filter_hash affects all records.
1684 * Update if the record is not in the notrace hash.
1685 */
1686 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1687 match = 1;
1688 } else {
1689 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1690 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1691
1692 /*
1693 * If filter_hash is set, we want to match all functions
1694 * that are in the hash but not in the other hash.
1695 *
1696 * If filter_hash is not set, then we are decrementing.
1697 * That means we match anything that is in the hash
1698 * and also in the other_hash. That is, we need to turn
1699 * off functions in the other hash because they are disabled
1700 * by this hash.
1701 */
1702 if (filter_hash && in_hash && !in_other_hash)
1703 match = 1;
1704 else if (!filter_hash && in_hash &&
1705 (in_other_hash || ftrace_hash_empty(other_hash)))
1706 match = 1;
1707 }
1708 if (!match)
1709 continue;
1710
1711 if (inc) {
1712 rec->flags++;
1713 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1714 return false;
1715
1716 /*
1717 * If there's only a single callback registered to a
1718 * function, and the ops has a trampoline registered
1719 * for it, then we can call it directly.
1720 */
1721 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1722 rec->flags |= FTRACE_FL_TRAMP;
1723 else
1724 /*
1725 * If we are adding another function callback
1726 * to this function, and the previous had a
1727 * custom trampoline in use, then we need to go
1728 * back to the default trampoline.
1729 */
1730 rec->flags &= ~FTRACE_FL_TRAMP;
1731
1732 /*
1733 * If any ops wants regs saved for this function
1734 * then all ops will get saved regs.
1735 */
1736 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1737 rec->flags |= FTRACE_FL_REGS;
1738 } else {
1739 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1740 return false;
1741 rec->flags--;
1742
1743 /*
1744 * If the rec had REGS enabled and the ops that is
1745 * being removed had REGS set, then see if there is
1746 * still any ops for this record that wants regs.
1747 * If not, we can stop recording them.
1748 */
1749 if (ftrace_rec_count(rec) > 0 &&
1750 rec->flags & FTRACE_FL_REGS &&
1751 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1752 if (!test_rec_ops_needs_regs(rec))
1753 rec->flags &= ~FTRACE_FL_REGS;
1754 }
1755
1756 /*
1757 * If the rec had TRAMP enabled, then it needs to
1758 * be cleared. As TRAMP can only be enabled iff
1759 * there is only a single ops attached to it.
1760 * In otherwords, always disable it on decrementing.
1761 * In the future, we may set it if rec count is
1762 * decremented to one, and the ops that is left
1763 * has a trampoline.
1764 */
1765 rec->flags &= ~FTRACE_FL_TRAMP;
1766
1767 /*
1768 * flags will be cleared in ftrace_check_record()
1769 * if rec count is zero.
1770 */
1771 }
1772 count++;
1773
1774 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1775 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1776
1777 /* Shortcut, if we handled all records, we are done. */
1778 if (!all && count == hash->count)
1779 return update;
1780 } while_for_each_ftrace_rec();
1781
1782 return update;
1783}
1784
1785static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1786 int filter_hash)
1787{
1788 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1789}
1790
1791static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1792 int filter_hash)
1793{
1794 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1795}
1796
1797static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1798 int filter_hash, int inc)
1799{
1800 struct ftrace_ops *op;
1801
1802 __ftrace_hash_rec_update(ops, filter_hash, inc);
1803
1804 if (ops->func_hash != &global_ops.local_hash)
1805 return;
1806
1807 /*
1808 * If the ops shares the global_ops hash, then we need to update
1809 * all ops that are enabled and use this hash.
1810 */
1811 do_for_each_ftrace_op(op, ftrace_ops_list) {
1812 /* Already done */
1813 if (op == ops)
1814 continue;
1815 if (op->func_hash == &global_ops.local_hash)
1816 __ftrace_hash_rec_update(op, filter_hash, inc);
1817 } while_for_each_ftrace_op(op);
1818}
1819
1820static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1821 int filter_hash)
1822{
1823 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1824}
1825
1826static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1827 int filter_hash)
1828{
1829 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1830}
1831
1832/*
1833 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1834 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1835 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1836 * Note that old_hash and new_hash has below meanings
1837 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1838 * - If the hash is EMPTY_HASH, it hits nothing
1839 * - Anything else hits the recs which match the hash entries.
1840 */
1841static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1842 struct ftrace_hash *old_hash,
1843 struct ftrace_hash *new_hash)
1844{
1845 struct ftrace_page *pg;
1846 struct dyn_ftrace *rec, *end = NULL;
1847 int in_old, in_new;
1848
1849 /* Only update if the ops has been registered */
1850 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1851 return 0;
1852
1853 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1854 return 0;
1855
1856 /*
1857 * Since the IPMODIFY is a very address sensitive action, we do not
1858 * allow ftrace_ops to set all functions to new hash.
1859 */
1860 if (!new_hash || !old_hash)
1861 return -EINVAL;
1862
1863 /* Update rec->flags */
1864 do_for_each_ftrace_rec(pg, rec) {
1865
1866 if (rec->flags & FTRACE_FL_DISABLED)
1867 continue;
1868
1869 /* We need to update only differences of filter_hash */
1870 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1871 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1872 if (in_old == in_new)
1873 continue;
1874
1875 if (in_new) {
1876 /* New entries must ensure no others are using it */
1877 if (rec->flags & FTRACE_FL_IPMODIFY)
1878 goto rollback;
1879 rec->flags |= FTRACE_FL_IPMODIFY;
1880 } else /* Removed entry */
1881 rec->flags &= ~FTRACE_FL_IPMODIFY;
1882 } while_for_each_ftrace_rec();
1883
1884 return 0;
1885
1886rollback:
1887 end = rec;
1888
1889 /* Roll back what we did above */
1890 do_for_each_ftrace_rec(pg, rec) {
1891
1892 if (rec->flags & FTRACE_FL_DISABLED)
1893 continue;
1894
1895 if (rec == end)
1896 goto err_out;
1897
1898 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1899 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1900 if (in_old == in_new)
1901 continue;
1902
1903 if (in_new)
1904 rec->flags &= ~FTRACE_FL_IPMODIFY;
1905 else
1906 rec->flags |= FTRACE_FL_IPMODIFY;
1907 } while_for_each_ftrace_rec();
1908
1909err_out:
1910 return -EBUSY;
1911}
1912
1913static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1914{
1915 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1916
1917 if (ftrace_hash_empty(hash))
1918 hash = NULL;
1919
1920 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1921}
1922
1923/* Disabling always succeeds */
1924static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1925{
1926 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1927
1928 if (ftrace_hash_empty(hash))
1929 hash = NULL;
1930
1931 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1932}
1933
1934static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1935 struct ftrace_hash *new_hash)
1936{
1937 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1938
1939 if (ftrace_hash_empty(old_hash))
1940 old_hash = NULL;
1941
1942 if (ftrace_hash_empty(new_hash))
1943 new_hash = NULL;
1944
1945 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1946}
1947
1948static void print_ip_ins(const char *fmt, const unsigned char *p)
1949{
1950 int i;
1951
1952 printk(KERN_CONT "%s", fmt);
1953
1954 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1955 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1956}
1957
1958static struct ftrace_ops *
1959ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1960static struct ftrace_ops *
1961ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1962
1963enum ftrace_bug_type ftrace_bug_type;
1964const void *ftrace_expected;
1965
1966static void print_bug_type(void)
1967{
1968 switch (ftrace_bug_type) {
1969 case FTRACE_BUG_UNKNOWN:
1970 break;
1971 case FTRACE_BUG_INIT:
1972 pr_info("Initializing ftrace call sites\n");
1973 break;
1974 case FTRACE_BUG_NOP:
1975 pr_info("Setting ftrace call site to NOP\n");
1976 break;
1977 case FTRACE_BUG_CALL:
1978 pr_info("Setting ftrace call site to call ftrace function\n");
1979 break;
1980 case FTRACE_BUG_UPDATE:
1981 pr_info("Updating ftrace call site to call a different ftrace function\n");
1982 break;
1983 }
1984}
1985
1986/**
1987 * ftrace_bug - report and shutdown function tracer
1988 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1989 * @rec: The record that failed
1990 *
1991 * The arch code that enables or disables the function tracing
1992 * can call ftrace_bug() when it has detected a problem in
1993 * modifying the code. @failed should be one of either:
1994 * EFAULT - if the problem happens on reading the @ip address
1995 * EINVAL - if what is read at @ip is not what was expected
1996 * EPERM - if the problem happens on writting to the @ip address
1997 */
1998void ftrace_bug(int failed, struct dyn_ftrace *rec)
1999{
2000 unsigned long ip = rec ? rec->ip : 0;
2001
2002 switch (failed) {
2003 case -EFAULT:
2004 FTRACE_WARN_ON_ONCE(1);
2005 pr_info("ftrace faulted on modifying ");
2006 print_ip_sym(ip);
2007 break;
2008 case -EINVAL:
2009 FTRACE_WARN_ON_ONCE(1);
2010 pr_info("ftrace failed to modify ");
2011 print_ip_sym(ip);
2012 print_ip_ins(" actual: ", (unsigned char *)ip);
2013 pr_cont("\n");
2014 if (ftrace_expected) {
2015 print_ip_ins(" expected: ", ftrace_expected);
2016 pr_cont("\n");
2017 }
2018 break;
2019 case -EPERM:
2020 FTRACE_WARN_ON_ONCE(1);
2021 pr_info("ftrace faulted on writing ");
2022 print_ip_sym(ip);
2023 break;
2024 default:
2025 FTRACE_WARN_ON_ONCE(1);
2026 pr_info("ftrace faulted on unknown error ");
2027 print_ip_sym(ip);
2028 }
2029 print_bug_type();
2030 if (rec) {
2031 struct ftrace_ops *ops = NULL;
2032
2033 pr_info("ftrace record flags: %lx\n", rec->flags);
2034 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2035 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2036 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2037 ops = ftrace_find_tramp_ops_any(rec);
2038 if (ops) {
2039 do {
2040 pr_cont("\ttramp: %pS (%pS)",
2041 (void *)ops->trampoline,
2042 (void *)ops->func);
2043 ops = ftrace_find_tramp_ops_next(rec, ops);
2044 } while (ops);
2045 } else
2046 pr_cont("\ttramp: ERROR!");
2047
2048 }
2049 ip = ftrace_get_addr_curr(rec);
2050 pr_cont("\n expected tramp: %lx\n", ip);
2051 }
2052}
2053
2054static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2055{
2056 unsigned long flag = 0UL;
2057
2058 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2059
2060 if (rec->flags & FTRACE_FL_DISABLED)
2061 return FTRACE_UPDATE_IGNORE;
2062
2063 /*
2064 * If we are updating calls:
2065 *
2066 * If the record has a ref count, then we need to enable it
2067 * because someone is using it.
2068 *
2069 * Otherwise we make sure its disabled.
2070 *
2071 * If we are disabling calls, then disable all records that
2072 * are enabled.
2073 */
2074 if (enable && ftrace_rec_count(rec))
2075 flag = FTRACE_FL_ENABLED;
2076
2077 /*
2078 * If enabling and the REGS flag does not match the REGS_EN, or
2079 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2080 * this record. Set flags to fail the compare against ENABLED.
2081 */
2082 if (flag) {
2083 if (!(rec->flags & FTRACE_FL_REGS) !=
2084 !(rec->flags & FTRACE_FL_REGS_EN))
2085 flag |= FTRACE_FL_REGS;
2086
2087 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2088 !(rec->flags & FTRACE_FL_TRAMP_EN))
2089 flag |= FTRACE_FL_TRAMP;
2090 }
2091
2092 /* If the state of this record hasn't changed, then do nothing */
2093 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2094 return FTRACE_UPDATE_IGNORE;
2095
2096 if (flag) {
2097 /* Save off if rec is being enabled (for return value) */
2098 flag ^= rec->flags & FTRACE_FL_ENABLED;
2099
2100 if (update) {
2101 rec->flags |= FTRACE_FL_ENABLED;
2102 if (flag & FTRACE_FL_REGS) {
2103 if (rec->flags & FTRACE_FL_REGS)
2104 rec->flags |= FTRACE_FL_REGS_EN;
2105 else
2106 rec->flags &= ~FTRACE_FL_REGS_EN;
2107 }
2108 if (flag & FTRACE_FL_TRAMP) {
2109 if (rec->flags & FTRACE_FL_TRAMP)
2110 rec->flags |= FTRACE_FL_TRAMP_EN;
2111 else
2112 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2113 }
2114 }
2115
2116 /*
2117 * If this record is being updated from a nop, then
2118 * return UPDATE_MAKE_CALL.
2119 * Otherwise,
2120 * return UPDATE_MODIFY_CALL to tell the caller to convert
2121 * from the save regs, to a non-save regs function or
2122 * vice versa, or from a trampoline call.
2123 */
2124 if (flag & FTRACE_FL_ENABLED) {
2125 ftrace_bug_type = FTRACE_BUG_CALL;
2126 return FTRACE_UPDATE_MAKE_CALL;
2127 }
2128
2129 ftrace_bug_type = FTRACE_BUG_UPDATE;
2130 return FTRACE_UPDATE_MODIFY_CALL;
2131 }
2132
2133 if (update) {
2134 /* If there's no more users, clear all flags */
2135 if (!ftrace_rec_count(rec))
2136 rec->flags = 0;
2137 else
2138 /*
2139 * Just disable the record, but keep the ops TRAMP
2140 * and REGS states. The _EN flags must be disabled though.
2141 */
2142 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2143 FTRACE_FL_REGS_EN);
2144 }
2145
2146 ftrace_bug_type = FTRACE_BUG_NOP;
2147 return FTRACE_UPDATE_MAKE_NOP;
2148}
2149
2150/**
2151 * ftrace_update_record, set a record that now is tracing or not
2152 * @rec: the record to update
2153 * @enable: set to 1 if the record is tracing, zero to force disable
2154 *
2155 * The records that represent all functions that can be traced need
2156 * to be updated when tracing has been enabled.
2157 */
2158int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2159{
2160 return ftrace_check_record(rec, enable, 1);
2161}
2162
2163/**
2164 * ftrace_test_record, check if the record has been enabled or not
2165 * @rec: the record to test
2166 * @enable: set to 1 to check if enabled, 0 if it is disabled
2167 *
2168 * The arch code may need to test if a record is already set to
2169 * tracing to determine how to modify the function code that it
2170 * represents.
2171 */
2172int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2173{
2174 return ftrace_check_record(rec, enable, 0);
2175}
2176
2177static struct ftrace_ops *
2178ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2179{
2180 struct ftrace_ops *op;
2181 unsigned long ip = rec->ip;
2182
2183 do_for_each_ftrace_op(op, ftrace_ops_list) {
2184
2185 if (!op->trampoline)
2186 continue;
2187
2188 if (hash_contains_ip(ip, op->func_hash))
2189 return op;
2190 } while_for_each_ftrace_op(op);
2191
2192 return NULL;
2193}
2194
2195static struct ftrace_ops *
2196ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2197 struct ftrace_ops *op)
2198{
2199 unsigned long ip = rec->ip;
2200
2201 while_for_each_ftrace_op(op) {
2202
2203 if (!op->trampoline)
2204 continue;
2205
2206 if (hash_contains_ip(ip, op->func_hash))
2207 return op;
2208 }
2209
2210 return NULL;
2211}
2212
2213static struct ftrace_ops *
2214ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2215{
2216 struct ftrace_ops *op;
2217 unsigned long ip = rec->ip;
2218
2219 /*
2220 * Need to check removed ops first.
2221 * If they are being removed, and this rec has a tramp,
2222 * and this rec is in the ops list, then it would be the
2223 * one with the tramp.
2224 */
2225 if (removed_ops) {
2226 if (hash_contains_ip(ip, &removed_ops->old_hash))
2227 return removed_ops;
2228 }
2229
2230 /*
2231 * Need to find the current trampoline for a rec.
2232 * Now, a trampoline is only attached to a rec if there
2233 * was a single 'ops' attached to it. But this can be called
2234 * when we are adding another op to the rec or removing the
2235 * current one. Thus, if the op is being added, we can
2236 * ignore it because it hasn't attached itself to the rec
2237 * yet.
2238 *
2239 * If an ops is being modified (hooking to different functions)
2240 * then we don't care about the new functions that are being
2241 * added, just the old ones (that are probably being removed).
2242 *
2243 * If we are adding an ops to a function that already is using
2244 * a trampoline, it needs to be removed (trampolines are only
2245 * for single ops connected), then an ops that is not being
2246 * modified also needs to be checked.
2247 */
2248 do_for_each_ftrace_op(op, ftrace_ops_list) {
2249
2250 if (!op->trampoline)
2251 continue;
2252
2253 /*
2254 * If the ops is being added, it hasn't gotten to
2255 * the point to be removed from this tree yet.
2256 */
2257 if (op->flags & FTRACE_OPS_FL_ADDING)
2258 continue;
2259
2260
2261 /*
2262 * If the ops is being modified and is in the old
2263 * hash, then it is probably being removed from this
2264 * function.
2265 */
2266 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2267 hash_contains_ip(ip, &op->old_hash))
2268 return op;
2269 /*
2270 * If the ops is not being added or modified, and it's
2271 * in its normal filter hash, then this must be the one
2272 * we want!
2273 */
2274 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2275 hash_contains_ip(ip, op->func_hash))
2276 return op;
2277
2278 } while_for_each_ftrace_op(op);
2279
2280 return NULL;
2281}
2282
2283static struct ftrace_ops *
2284ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2285{
2286 struct ftrace_ops *op;
2287 unsigned long ip = rec->ip;
2288
2289 do_for_each_ftrace_op(op, ftrace_ops_list) {
2290 /* pass rec in as regs to have non-NULL val */
2291 if (hash_contains_ip(ip, op->func_hash))
2292 return op;
2293 } while_for_each_ftrace_op(op);
2294
2295 return NULL;
2296}
2297
2298/**
2299 * ftrace_get_addr_new - Get the call address to set to
2300 * @rec: The ftrace record descriptor
2301 *
2302 * If the record has the FTRACE_FL_REGS set, that means that it
2303 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2304 * is not not set, then it wants to convert to the normal callback.
2305 *
2306 * Returns the address of the trampoline to set to
2307 */
2308unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2309{
2310 struct ftrace_ops *ops;
2311
2312 /* Trampolines take precedence over regs */
2313 if (rec->flags & FTRACE_FL_TRAMP) {
2314 ops = ftrace_find_tramp_ops_new(rec);
2315 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2316 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2317 (void *)rec->ip, (void *)rec->ip, rec->flags);
2318 /* Ftrace is shutting down, return anything */
2319 return (unsigned long)FTRACE_ADDR;
2320 }
2321 return ops->trampoline;
2322 }
2323
2324 if (rec->flags & FTRACE_FL_REGS)
2325 return (unsigned long)FTRACE_REGS_ADDR;
2326 else
2327 return (unsigned long)FTRACE_ADDR;
2328}
2329
2330/**
2331 * ftrace_get_addr_curr - Get the call address that is already there
2332 * @rec: The ftrace record descriptor
2333 *
2334 * The FTRACE_FL_REGS_EN is set when the record already points to
2335 * a function that saves all the regs. Basically the '_EN' version
2336 * represents the current state of the function.
2337 *
2338 * Returns the address of the trampoline that is currently being called
2339 */
2340unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2341{
2342 struct ftrace_ops *ops;
2343
2344 /* Trampolines take precedence over regs */
2345 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2346 ops = ftrace_find_tramp_ops_curr(rec);
2347 if (FTRACE_WARN_ON(!ops)) {
2348 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2349 (void *)rec->ip, (void *)rec->ip);
2350 /* Ftrace is shutting down, return anything */
2351 return (unsigned long)FTRACE_ADDR;
2352 }
2353 return ops->trampoline;
2354 }
2355
2356 if (rec->flags & FTRACE_FL_REGS_EN)
2357 return (unsigned long)FTRACE_REGS_ADDR;
2358 else
2359 return (unsigned long)FTRACE_ADDR;
2360}
2361
2362static int
2363__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2364{
2365 unsigned long ftrace_old_addr;
2366 unsigned long ftrace_addr;
2367 int ret;
2368
2369 ftrace_addr = ftrace_get_addr_new(rec);
2370
2371 /* This needs to be done before we call ftrace_update_record */
2372 ftrace_old_addr = ftrace_get_addr_curr(rec);
2373
2374 ret = ftrace_update_record(rec, enable);
2375
2376 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2377
2378 switch (ret) {
2379 case FTRACE_UPDATE_IGNORE:
2380 return 0;
2381
2382 case FTRACE_UPDATE_MAKE_CALL:
2383 ftrace_bug_type = FTRACE_BUG_CALL;
2384 return ftrace_make_call(rec, ftrace_addr);
2385
2386 case FTRACE_UPDATE_MAKE_NOP:
2387 ftrace_bug_type = FTRACE_BUG_NOP;
2388 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2389
2390 case FTRACE_UPDATE_MODIFY_CALL:
2391 ftrace_bug_type = FTRACE_BUG_UPDATE;
2392 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2393 }
2394
2395 return -1; /* unknow ftrace bug */
2396}
2397
2398void __weak ftrace_replace_code(int enable)
2399{
2400 struct dyn_ftrace *rec;
2401 struct ftrace_page *pg;
2402 int failed;
2403
2404 if (unlikely(ftrace_disabled))
2405 return;
2406
2407 do_for_each_ftrace_rec(pg, rec) {
2408
2409 if (rec->flags & FTRACE_FL_DISABLED)
2410 continue;
2411
2412 failed = __ftrace_replace_code(rec, enable);
2413 if (failed) {
2414 ftrace_bug(failed, rec);
2415 /* Stop processing */
2416 return;
2417 }
2418 } while_for_each_ftrace_rec();
2419}
2420
2421struct ftrace_rec_iter {
2422 struct ftrace_page *pg;
2423 int index;
2424};
2425
2426/**
2427 * ftrace_rec_iter_start, start up iterating over traced functions
2428 *
2429 * Returns an iterator handle that is used to iterate over all
2430 * the records that represent address locations where functions
2431 * are traced.
2432 *
2433 * May return NULL if no records are available.
2434 */
2435struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2436{
2437 /*
2438 * We only use a single iterator.
2439 * Protected by the ftrace_lock mutex.
2440 */
2441 static struct ftrace_rec_iter ftrace_rec_iter;
2442 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2443
2444 iter->pg = ftrace_pages_start;
2445 iter->index = 0;
2446
2447 /* Could have empty pages */
2448 while (iter->pg && !iter->pg->index)
2449 iter->pg = iter->pg->next;
2450
2451 if (!iter->pg)
2452 return NULL;
2453
2454 return iter;
2455}
2456
2457/**
2458 * ftrace_rec_iter_next, get the next record to process.
2459 * @iter: The handle to the iterator.
2460 *
2461 * Returns the next iterator after the given iterator @iter.
2462 */
2463struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2464{
2465 iter->index++;
2466
2467 if (iter->index >= iter->pg->index) {
2468 iter->pg = iter->pg->next;
2469 iter->index = 0;
2470
2471 /* Could have empty pages */
2472 while (iter->pg && !iter->pg->index)
2473 iter->pg = iter->pg->next;
2474 }
2475
2476 if (!iter->pg)
2477 return NULL;
2478
2479 return iter;
2480}
2481
2482/**
2483 * ftrace_rec_iter_record, get the record at the iterator location
2484 * @iter: The current iterator location
2485 *
2486 * Returns the record that the current @iter is at.
2487 */
2488struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2489{
2490 return &iter->pg->records[iter->index];
2491}
2492
2493static int
2494ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2495{
2496 int ret;
2497
2498 if (unlikely(ftrace_disabled))
2499 return 0;
2500
2501 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2502 if (ret) {
2503 ftrace_bug_type = FTRACE_BUG_INIT;
2504 ftrace_bug(ret, rec);
2505 return 0;
2506 }
2507 return 1;
2508}
2509
2510/*
2511 * archs can override this function if they must do something
2512 * before the modifying code is performed.
2513 */
2514int __weak ftrace_arch_code_modify_prepare(void)
2515{
2516 return 0;
2517}
2518
2519/*
2520 * archs can override this function if they must do something
2521 * after the modifying code is performed.
2522 */
2523int __weak ftrace_arch_code_modify_post_process(void)
2524{
2525 return 0;
2526}
2527
2528void ftrace_modify_all_code(int command)
2529{
2530 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2531 int err = 0;
2532
2533 /*
2534 * If the ftrace_caller calls a ftrace_ops func directly,
2535 * we need to make sure that it only traces functions it
2536 * expects to trace. When doing the switch of functions,
2537 * we need to update to the ftrace_ops_list_func first
2538 * before the transition between old and new calls are set,
2539 * as the ftrace_ops_list_func will check the ops hashes
2540 * to make sure the ops are having the right functions
2541 * traced.
2542 */
2543 if (update) {
2544 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2545 if (FTRACE_WARN_ON(err))
2546 return;
2547 }
2548
2549 if (command & FTRACE_UPDATE_CALLS)
2550 ftrace_replace_code(1);
2551 else if (command & FTRACE_DISABLE_CALLS)
2552 ftrace_replace_code(0);
2553
2554 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2555 function_trace_op = set_function_trace_op;
2556 smp_wmb();
2557 /* If irqs are disabled, we are in stop machine */
2558 if (!irqs_disabled())
2559 smp_call_function(ftrace_sync_ipi, NULL, 1);
2560 err = ftrace_update_ftrace_func(ftrace_trace_function);
2561 if (FTRACE_WARN_ON(err))
2562 return;
2563 }
2564
2565 if (command & FTRACE_START_FUNC_RET)
2566 err = ftrace_enable_ftrace_graph_caller();
2567 else if (command & FTRACE_STOP_FUNC_RET)
2568 err = ftrace_disable_ftrace_graph_caller();
2569 FTRACE_WARN_ON(err);
2570}
2571
2572static int __ftrace_modify_code(void *data)
2573{
2574 int *command = data;
2575
2576 ftrace_modify_all_code(*command);
2577
2578 return 0;
2579}
2580
2581/**
2582 * ftrace_run_stop_machine, go back to the stop machine method
2583 * @command: The command to tell ftrace what to do
2584 *
2585 * If an arch needs to fall back to the stop machine method, the
2586 * it can call this function.
2587 */
2588void ftrace_run_stop_machine(int command)
2589{
2590 stop_machine(__ftrace_modify_code, &command, NULL);
2591}
2592
2593/**
2594 * arch_ftrace_update_code, modify the code to trace or not trace
2595 * @command: The command that needs to be done
2596 *
2597 * Archs can override this function if it does not need to
2598 * run stop_machine() to modify code.
2599 */
2600void __weak arch_ftrace_update_code(int command)
2601{
2602 ftrace_run_stop_machine(command);
2603}
2604
2605static void ftrace_run_update_code(int command)
2606{
2607 int ret;
2608
2609 ret = ftrace_arch_code_modify_prepare();
2610 FTRACE_WARN_ON(ret);
2611 if (ret)
2612 return;
2613
2614 /*
2615 * By default we use stop_machine() to modify the code.
2616 * But archs can do what ever they want as long as it
2617 * is safe. The stop_machine() is the safest, but also
2618 * produces the most overhead.
2619 */
2620 arch_ftrace_update_code(command);
2621
2622 ret = ftrace_arch_code_modify_post_process();
2623 FTRACE_WARN_ON(ret);
2624}
2625
2626static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2627 struct ftrace_ops_hash *old_hash)
2628{
2629 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2630 ops->old_hash.filter_hash = old_hash->filter_hash;
2631 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2632 ftrace_run_update_code(command);
2633 ops->old_hash.filter_hash = NULL;
2634 ops->old_hash.notrace_hash = NULL;
2635 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2636}
2637
2638static ftrace_func_t saved_ftrace_func;
2639static int ftrace_start_up;
2640
2641void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2642{
2643}
2644
2645static void per_cpu_ops_free(struct ftrace_ops *ops)
2646{
2647 free_percpu(ops->disabled);
2648}
2649
2650static void ftrace_startup_enable(int command)
2651{
2652 if (saved_ftrace_func != ftrace_trace_function) {
2653 saved_ftrace_func = ftrace_trace_function;
2654 command |= FTRACE_UPDATE_TRACE_FUNC;
2655 }
2656
2657 if (!command || !ftrace_enabled)
2658 return;
2659
2660 ftrace_run_update_code(command);
2661}
2662
2663static void ftrace_startup_all(int command)
2664{
2665 update_all_ops = true;
2666 ftrace_startup_enable(command);
2667 update_all_ops = false;
2668}
2669
2670static int ftrace_startup(struct ftrace_ops *ops, int command)
2671{
2672 int ret;
2673
2674 if (unlikely(ftrace_disabled))
2675 return -ENODEV;
2676
2677 ret = __register_ftrace_function(ops);
2678 if (ret)
2679 return ret;
2680
2681 ftrace_start_up++;
2682
2683 /*
2684 * Note that ftrace probes uses this to start up
2685 * and modify functions it will probe. But we still
2686 * set the ADDING flag for modification, as probes
2687 * do not have trampolines. If they add them in the
2688 * future, then the probes will need to distinguish
2689 * between adding and updating probes.
2690 */
2691 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2692
2693 ret = ftrace_hash_ipmodify_enable(ops);
2694 if (ret < 0) {
2695 /* Rollback registration process */
2696 __unregister_ftrace_function(ops);
2697 ftrace_start_up--;
2698 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2699 return ret;
2700 }
2701
2702 if (ftrace_hash_rec_enable(ops, 1))
2703 command |= FTRACE_UPDATE_CALLS;
2704
2705 ftrace_startup_enable(command);
2706
2707 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2708
2709 return 0;
2710}
2711
2712static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2713{
2714 int ret;
2715
2716 if (unlikely(ftrace_disabled))
2717 return -ENODEV;
2718
2719 ret = __unregister_ftrace_function(ops);
2720 if (ret)
2721 return ret;
2722
2723 ftrace_start_up--;
2724 /*
2725 * Just warn in case of unbalance, no need to kill ftrace, it's not
2726 * critical but the ftrace_call callers may be never nopped again after
2727 * further ftrace uses.
2728 */
2729 WARN_ON_ONCE(ftrace_start_up < 0);
2730
2731 /* Disabling ipmodify never fails */
2732 ftrace_hash_ipmodify_disable(ops);
2733
2734 if (ftrace_hash_rec_disable(ops, 1))
2735 command |= FTRACE_UPDATE_CALLS;
2736
2737 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2738
2739 if (saved_ftrace_func != ftrace_trace_function) {
2740 saved_ftrace_func = ftrace_trace_function;
2741 command |= FTRACE_UPDATE_TRACE_FUNC;
2742 }
2743
2744 if (!command || !ftrace_enabled) {
2745 /*
2746 * If these are per_cpu ops, they still need their
2747 * per_cpu field freed. Since, function tracing is
2748 * not currently active, we can just free them
2749 * without synchronizing all CPUs.
2750 */
2751 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2752 per_cpu_ops_free(ops);
2753 return 0;
2754 }
2755
2756 /*
2757 * If the ops uses a trampoline, then it needs to be
2758 * tested first on update.
2759 */
2760 ops->flags |= FTRACE_OPS_FL_REMOVING;
2761 removed_ops = ops;
2762
2763 /* The trampoline logic checks the old hashes */
2764 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2765 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2766
2767 ftrace_run_update_code(command);
2768
2769 /*
2770 * If there's no more ops registered with ftrace, run a
2771 * sanity check to make sure all rec flags are cleared.
2772 */
2773 if (ftrace_ops_list == &ftrace_list_end) {
2774 struct ftrace_page *pg;
2775 struct dyn_ftrace *rec;
2776
2777 do_for_each_ftrace_rec(pg, rec) {
2778 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2779 pr_warn(" %pS flags:%lx\n",
2780 (void *)rec->ip, rec->flags);
2781 } while_for_each_ftrace_rec();
2782 }
2783
2784 ops->old_hash.filter_hash = NULL;
2785 ops->old_hash.notrace_hash = NULL;
2786
2787 removed_ops = NULL;
2788 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2789
2790 /*
2791 * Dynamic ops may be freed, we must make sure that all
2792 * callers are done before leaving this function.
2793 * The same goes for freeing the per_cpu data of the per_cpu
2794 * ops.
2795 *
2796 * Again, normal synchronize_sched() is not good enough.
2797 * We need to do a hard force of sched synchronization.
2798 * This is because we use preempt_disable() to do RCU, but
2799 * the function tracers can be called where RCU is not watching
2800 * (like before user_exit()). We can not rely on the RCU
2801 * infrastructure to do the synchronization, thus we must do it
2802 * ourselves.
2803 */
2804 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2805 schedule_on_each_cpu(ftrace_sync);
2806
2807 arch_ftrace_trampoline_free(ops);
2808
2809 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2810 per_cpu_ops_free(ops);
2811 }
2812
2813 return 0;
2814}
2815
2816static void ftrace_startup_sysctl(void)
2817{
2818 int command;
2819
2820 if (unlikely(ftrace_disabled))
2821 return;
2822
2823 /* Force update next time */
2824 saved_ftrace_func = NULL;
2825 /* ftrace_start_up is true if we want ftrace running */
2826 if (ftrace_start_up) {
2827 command = FTRACE_UPDATE_CALLS;
2828 if (ftrace_graph_active)
2829 command |= FTRACE_START_FUNC_RET;
2830 ftrace_startup_enable(command);
2831 }
2832}
2833
2834static void ftrace_shutdown_sysctl(void)
2835{
2836 int command;
2837
2838 if (unlikely(ftrace_disabled))
2839 return;
2840
2841 /* ftrace_start_up is true if ftrace is running */
2842 if (ftrace_start_up) {
2843 command = FTRACE_DISABLE_CALLS;
2844 if (ftrace_graph_active)
2845 command |= FTRACE_STOP_FUNC_RET;
2846 ftrace_run_update_code(command);
2847 }
2848}
2849
2850static u64 ftrace_update_time;
2851unsigned long ftrace_update_tot_cnt;
2852
2853static inline int ops_traces_mod(struct ftrace_ops *ops)
2854{
2855 /*
2856 * Filter_hash being empty will default to trace module.
2857 * But notrace hash requires a test of individual module functions.
2858 */
2859 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2860 ftrace_hash_empty(ops->func_hash->notrace_hash);
2861}
2862
2863/*
2864 * Check if the current ops references the record.
2865 *
2866 * If the ops traces all functions, then it was already accounted for.
2867 * If the ops does not trace the current record function, skip it.
2868 * If the ops ignores the function via notrace filter, skip it.
2869 */
2870static inline bool
2871ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2872{
2873 /* If ops isn't enabled, ignore it */
2874 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2875 return 0;
2876
2877 /* If ops traces all then it includes this function */
2878 if (ops_traces_mod(ops))
2879 return 1;
2880
2881 /* The function must be in the filter */
2882 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2883 !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2884 return 0;
2885
2886 /* If in notrace hash, we ignore it too */
2887 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2888 return 0;
2889
2890 return 1;
2891}
2892
2893static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2894{
2895 struct ftrace_page *pg;
2896 struct dyn_ftrace *p;
2897 u64 start, stop;
2898 unsigned long update_cnt = 0;
2899 unsigned long rec_flags = 0;
2900 int i;
2901
2902 start = ftrace_now(raw_smp_processor_id());
2903
2904 /*
2905 * When a module is loaded, this function is called to convert
2906 * the calls to mcount in its text to nops, and also to create
2907 * an entry in the ftrace data. Now, if ftrace is activated
2908 * after this call, but before the module sets its text to
2909 * read-only, the modification of enabling ftrace can fail if
2910 * the read-only is done while ftrace is converting the calls.
2911 * To prevent this, the module's records are set as disabled
2912 * and will be enabled after the call to set the module's text
2913 * to read-only.
2914 */
2915 if (mod)
2916 rec_flags |= FTRACE_FL_DISABLED;
2917
2918 for (pg = new_pgs; pg; pg = pg->next) {
2919
2920 for (i = 0; i < pg->index; i++) {
2921
2922 /* If something went wrong, bail without enabling anything */
2923 if (unlikely(ftrace_disabled))
2924 return -1;
2925
2926 p = &pg->records[i];
2927 p->flags = rec_flags;
2928
2929 /*
2930 * Do the initial record conversion from mcount jump
2931 * to the NOP instructions.
2932 */
2933 if (!ftrace_code_disable(mod, p))
2934 break;
2935
2936 update_cnt++;
2937 }
2938 }
2939
2940 stop = ftrace_now(raw_smp_processor_id());
2941 ftrace_update_time = stop - start;
2942 ftrace_update_tot_cnt += update_cnt;
2943
2944 return 0;
2945}
2946
2947static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2948{
2949 int order;
2950 int cnt;
2951
2952 if (WARN_ON(!count))
2953 return -EINVAL;
2954
2955 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2956
2957 /*
2958 * We want to fill as much as possible. No more than a page
2959 * may be empty.
2960 */
2961 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2962 order--;
2963
2964 again:
2965 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2966
2967 if (!pg->records) {
2968 /* if we can't allocate this size, try something smaller */
2969 if (!order)
2970 return -ENOMEM;
2971 order >>= 1;
2972 goto again;
2973 }
2974
2975 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2976 pg->size = cnt;
2977
2978 if (cnt > count)
2979 cnt = count;
2980
2981 return cnt;
2982}
2983
2984static struct ftrace_page *
2985ftrace_allocate_pages(unsigned long num_to_init)
2986{
2987 struct ftrace_page *start_pg;
2988 struct ftrace_page *pg;
2989 int order;
2990 int cnt;
2991
2992 if (!num_to_init)
2993 return 0;
2994
2995 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2996 if (!pg)
2997 return NULL;
2998
2999 /*
3000 * Try to allocate as much as possible in one continues
3001 * location that fills in all of the space. We want to
3002 * waste as little space as possible.
3003 */
3004 for (;;) {
3005 cnt = ftrace_allocate_records(pg, num_to_init);
3006 if (cnt < 0)
3007 goto free_pages;
3008
3009 num_to_init -= cnt;
3010 if (!num_to_init)
3011 break;
3012
3013 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3014 if (!pg->next)
3015 goto free_pages;
3016
3017 pg = pg->next;
3018 }
3019
3020 return start_pg;
3021
3022 free_pages:
3023 pg = start_pg;
3024 while (pg) {
3025 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3026 free_pages((unsigned long)pg->records, order);
3027 start_pg = pg->next;
3028 kfree(pg);
3029 pg = start_pg;
3030 }
3031 pr_info("ftrace: FAILED to allocate memory for functions\n");
3032 return NULL;
3033}
3034
3035#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3036
3037struct ftrace_iterator {
3038 loff_t pos;
3039 loff_t func_pos;
3040 struct ftrace_page *pg;
3041 struct dyn_ftrace *func;
3042 struct ftrace_func_probe *probe;
3043 struct trace_parser parser;
3044 struct ftrace_hash *hash;
3045 struct ftrace_ops *ops;
3046 int hidx;
3047 int idx;
3048 unsigned flags;
3049};
3050
3051static void *
3052t_hash_next(struct seq_file *m, loff_t *pos)
3053{
3054 struct ftrace_iterator *iter = m->private;
3055 struct hlist_node *hnd = NULL;
3056 struct hlist_head *hhd;
3057
3058 (*pos)++;
3059 iter->pos = *pos;
3060
3061 if (iter->probe)
3062 hnd = &iter->probe->node;
3063 retry:
3064 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3065 return NULL;
3066
3067 hhd = &ftrace_func_hash[iter->hidx];
3068
3069 if (hlist_empty(hhd)) {
3070 iter->hidx++;
3071 hnd = NULL;
3072 goto retry;
3073 }
3074
3075 if (!hnd)
3076 hnd = hhd->first;
3077 else {
3078 hnd = hnd->next;
3079 if (!hnd) {
3080 iter->hidx++;
3081 goto retry;
3082 }
3083 }
3084
3085 if (WARN_ON_ONCE(!hnd))
3086 return NULL;
3087
3088 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3089
3090 return iter;
3091}
3092
3093static void *t_hash_start(struct seq_file *m, loff_t *pos)
3094{
3095 struct ftrace_iterator *iter = m->private;
3096 void *p = NULL;
3097 loff_t l;
3098
3099 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3100 return NULL;
3101
3102 if (iter->func_pos > *pos)
3103 return NULL;
3104
3105 iter->hidx = 0;
3106 for (l = 0; l <= (*pos - iter->func_pos); ) {
3107 p = t_hash_next(m, &l);
3108 if (!p)
3109 break;
3110 }
3111 if (!p)
3112 return NULL;
3113
3114 /* Only set this if we have an item */
3115 iter->flags |= FTRACE_ITER_HASH;
3116
3117 return iter;
3118}
3119
3120static int
3121t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3122{
3123 struct ftrace_func_probe *rec;
3124
3125 rec = iter->probe;
3126 if (WARN_ON_ONCE(!rec))
3127 return -EIO;
3128
3129 if (rec->ops->print)
3130 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3131
3132 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3133
3134 if (rec->data)
3135 seq_printf(m, ":%p", rec->data);
3136 seq_putc(m, '\n');
3137
3138 return 0;
3139}
3140
3141static void *
3142t_next(struct seq_file *m, void *v, loff_t *pos)
3143{
3144 struct ftrace_iterator *iter = m->private;
3145 struct ftrace_ops *ops = iter->ops;
3146 struct dyn_ftrace *rec = NULL;
3147
3148 if (unlikely(ftrace_disabled))
3149 return NULL;
3150
3151 if (iter->flags & FTRACE_ITER_HASH)
3152 return t_hash_next(m, pos);
3153
3154 (*pos)++;
3155 iter->pos = iter->func_pos = *pos;
3156
3157 if (iter->flags & FTRACE_ITER_PRINTALL)
3158 return t_hash_start(m, pos);
3159
3160 retry:
3161 if (iter->idx >= iter->pg->index) {
3162 if (iter->pg->next) {
3163 iter->pg = iter->pg->next;
3164 iter->idx = 0;
3165 goto retry;
3166 }
3167 } else {
3168 rec = &iter->pg->records[iter->idx++];
3169 if (((iter->flags & FTRACE_ITER_FILTER) &&
3170 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3171
3172 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3173 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3174
3175 ((iter->flags & FTRACE_ITER_ENABLED) &&
3176 !(rec->flags & FTRACE_FL_ENABLED))) {
3177
3178 rec = NULL;
3179 goto retry;
3180 }
3181 }
3182
3183 if (!rec)
3184 return t_hash_start(m, pos);
3185
3186 iter->func = rec;
3187
3188 return iter;
3189}
3190
3191static void reset_iter_read(struct ftrace_iterator *iter)
3192{
3193 iter->pos = 0;
3194 iter->func_pos = 0;
3195 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3196}
3197
3198static void *t_start(struct seq_file *m, loff_t *pos)
3199{
3200 struct ftrace_iterator *iter = m->private;
3201 struct ftrace_ops *ops = iter->ops;
3202 void *p = NULL;
3203 loff_t l;
3204
3205 mutex_lock(&ftrace_lock);
3206
3207 if (unlikely(ftrace_disabled))
3208 return NULL;
3209
3210 /*
3211 * If an lseek was done, then reset and start from beginning.
3212 */
3213 if (*pos < iter->pos)
3214 reset_iter_read(iter);
3215
3216 /*
3217 * For set_ftrace_filter reading, if we have the filter
3218 * off, we can short cut and just print out that all
3219 * functions are enabled.
3220 */
3221 if ((iter->flags & FTRACE_ITER_FILTER &&
3222 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3223 (iter->flags & FTRACE_ITER_NOTRACE &&
3224 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3225 if (*pos > 0)
3226 return t_hash_start(m, pos);
3227 iter->flags |= FTRACE_ITER_PRINTALL;
3228 /* reset in case of seek/pread */
3229 iter->flags &= ~FTRACE_ITER_HASH;
3230 return iter;
3231 }
3232
3233 if (iter->flags & FTRACE_ITER_HASH)
3234 return t_hash_start(m, pos);
3235
3236 /*
3237 * Unfortunately, we need to restart at ftrace_pages_start
3238 * every time we let go of the ftrace_mutex. This is because
3239 * those pointers can change without the lock.
3240 */
3241 iter->pg = ftrace_pages_start;
3242 iter->idx = 0;
3243 for (l = 0; l <= *pos; ) {
3244 p = t_next(m, p, &l);
3245 if (!p)
3246 break;
3247 }
3248
3249 if (!p)
3250 return t_hash_start(m, pos);
3251
3252 return iter;
3253}
3254
3255static void t_stop(struct seq_file *m, void *p)
3256{
3257 mutex_unlock(&ftrace_lock);
3258}
3259
3260void * __weak
3261arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3262{
3263 return NULL;
3264}
3265
3266static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3267 struct dyn_ftrace *rec)
3268{
3269 void *ptr;
3270
3271 ptr = arch_ftrace_trampoline_func(ops, rec);
3272 if (ptr)
3273 seq_printf(m, " ->%pS", ptr);
3274}
3275
3276static int t_show(struct seq_file *m, void *v)
3277{
3278 struct ftrace_iterator *iter = m->private;
3279 struct dyn_ftrace *rec;
3280
3281 if (iter->flags & FTRACE_ITER_HASH)
3282 return t_hash_show(m, iter);
3283
3284 if (iter->flags & FTRACE_ITER_PRINTALL) {
3285 if (iter->flags & FTRACE_ITER_NOTRACE)
3286 seq_puts(m, "#### no functions disabled ####\n");
3287 else
3288 seq_puts(m, "#### all functions enabled ####\n");
3289 return 0;
3290 }
3291
3292 rec = iter->func;
3293
3294 if (!rec)
3295 return 0;
3296
3297 seq_printf(m, "%ps", (void *)rec->ip);
3298 if (iter->flags & FTRACE_ITER_ENABLED) {
3299 struct ftrace_ops *ops;
3300
3301 seq_printf(m, " (%ld)%s%s",
3302 ftrace_rec_count(rec),
3303 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3304 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3305 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3306 ops = ftrace_find_tramp_ops_any(rec);
3307 if (ops) {
3308 do {
3309 seq_printf(m, "\ttramp: %pS (%pS)",
3310 (void *)ops->trampoline,
3311 (void *)ops->func);
3312 add_trampoline_func(m, ops, rec);
3313 ops = ftrace_find_tramp_ops_next(rec, ops);
3314 } while (ops);
3315 } else
3316 seq_puts(m, "\ttramp: ERROR!");
3317 } else {
3318 add_trampoline_func(m, NULL, rec);
3319 }
3320 }
3321
3322 seq_putc(m, '\n');
3323
3324 return 0;
3325}
3326
3327static const struct seq_operations show_ftrace_seq_ops = {
3328 .start = t_start,
3329 .next = t_next,
3330 .stop = t_stop,
3331 .show = t_show,
3332};
3333
3334static int
3335ftrace_avail_open(struct inode *inode, struct file *file)
3336{
3337 struct ftrace_iterator *iter;
3338
3339 if (unlikely(ftrace_disabled))
3340 return -ENODEV;
3341
3342 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3343 if (iter) {
3344 iter->pg = ftrace_pages_start;
3345 iter->ops = &global_ops;
3346 }
3347
3348 return iter ? 0 : -ENOMEM;
3349}
3350
3351static int
3352ftrace_enabled_open(struct inode *inode, struct file *file)
3353{
3354 struct ftrace_iterator *iter;
3355
3356 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3357 if (iter) {
3358 iter->pg = ftrace_pages_start;
3359 iter->flags = FTRACE_ITER_ENABLED;
3360 iter->ops = &global_ops;
3361 }
3362
3363 return iter ? 0 : -ENOMEM;
3364}
3365
3366/**
3367 * ftrace_regex_open - initialize function tracer filter files
3368 * @ops: The ftrace_ops that hold the hash filters
3369 * @flag: The type of filter to process
3370 * @inode: The inode, usually passed in to your open routine
3371 * @file: The file, usually passed in to your open routine
3372 *
3373 * ftrace_regex_open() initializes the filter files for the
3374 * @ops. Depending on @flag it may process the filter hash or
3375 * the notrace hash of @ops. With this called from the open
3376 * routine, you can use ftrace_filter_write() for the write
3377 * routine if @flag has FTRACE_ITER_FILTER set, or
3378 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3379 * tracing_lseek() should be used as the lseek routine, and
3380 * release must call ftrace_regex_release().
3381 */
3382int
3383ftrace_regex_open(struct ftrace_ops *ops, int flag,
3384 struct inode *inode, struct file *file)
3385{
3386 struct ftrace_iterator *iter;
3387 struct ftrace_hash *hash;
3388 int ret = 0;
3389
3390 ftrace_ops_init(ops);
3391
3392 if (unlikely(ftrace_disabled))
3393 return -ENODEV;
3394
3395 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3396 if (!iter)
3397 return -ENOMEM;
3398
3399 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3400 kfree(iter);
3401 return -ENOMEM;
3402 }
3403
3404 iter->ops = ops;
3405 iter->flags = flag;
3406
3407 mutex_lock(&ops->func_hash->regex_lock);
3408
3409 if (flag & FTRACE_ITER_NOTRACE)
3410 hash = ops->func_hash->notrace_hash;
3411 else
3412 hash = ops->func_hash->filter_hash;
3413
3414 if (file->f_mode & FMODE_WRITE) {
3415 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3416
3417 if (file->f_flags & O_TRUNC)
3418 iter->hash = alloc_ftrace_hash(size_bits);
3419 else
3420 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3421
3422 if (!iter->hash) {
3423 trace_parser_put(&iter->parser);
3424 kfree(iter);
3425 ret = -ENOMEM;
3426 goto out_unlock;
3427 }
3428 }
3429
3430 if (file->f_mode & FMODE_READ) {
3431 iter->pg = ftrace_pages_start;
3432
3433 ret = seq_open(file, &show_ftrace_seq_ops);
3434 if (!ret) {
3435 struct seq_file *m = file->private_data;
3436 m->private = iter;
3437 } else {
3438 /* Failed */
3439 free_ftrace_hash(iter->hash);
3440 trace_parser_put(&iter->parser);
3441 kfree(iter);
3442 }
3443 } else
3444 file->private_data = iter;
3445
3446 out_unlock:
3447 mutex_unlock(&ops->func_hash->regex_lock);
3448
3449 return ret;
3450}
3451
3452static int
3453ftrace_filter_open(struct inode *inode, struct file *file)
3454{
3455 struct ftrace_ops *ops = inode->i_private;
3456
3457 return ftrace_regex_open(ops,
3458 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3459 inode, file);
3460}
3461
3462static int
3463ftrace_notrace_open(struct inode *inode, struct file *file)
3464{
3465 struct ftrace_ops *ops = inode->i_private;
3466
3467 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3468 inode, file);
3469}
3470
3471/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3472struct ftrace_glob {
3473 char *search;
3474 unsigned len;
3475 int type;
3476};
3477
3478/*
3479 * If symbols in an architecture don't correspond exactly to the user-visible
3480 * name of what they represent, it is possible to define this function to
3481 * perform the necessary adjustments.
3482*/
3483char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3484{
3485 return str;
3486}
3487
3488static int ftrace_match(char *str, struct ftrace_glob *g)
3489{
3490 int matched = 0;
3491 int slen;
3492
3493 str = arch_ftrace_match_adjust(str, g->search);
3494
3495 switch (g->type) {
3496 case MATCH_FULL:
3497 if (strcmp(str, g->search) == 0)
3498 matched = 1;
3499 break;
3500 case MATCH_FRONT_ONLY:
3501 if (strncmp(str, g->search, g->len) == 0)
3502 matched = 1;
3503 break;
3504 case MATCH_MIDDLE_ONLY:
3505 if (strstr(str, g->search))
3506 matched = 1;
3507 break;
3508 case MATCH_END_ONLY:
3509 slen = strlen(str);
3510 if (slen >= g->len &&
3511 memcmp(str + slen - g->len, g->search, g->len) == 0)
3512 matched = 1;
3513 break;
3514 case MATCH_GLOB:
3515 if (glob_match(g->search, str))
3516 matched = 1;
3517 break;
3518 }
3519
3520 return matched;
3521}
3522
3523static int
3524enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3525{
3526 struct ftrace_func_entry *entry;
3527 int ret = 0;
3528
3529 entry = ftrace_lookup_ip(hash, rec->ip);
3530 if (clear_filter) {
3531 /* Do nothing if it doesn't exist */
3532 if (!entry)
3533 return 0;
3534
3535 free_hash_entry(hash, entry);
3536 } else {
3537 /* Do nothing if it exists */
3538 if (entry)
3539 return 0;
3540
3541 ret = add_hash_entry(hash, rec->ip);
3542 }
3543 return ret;
3544}
3545
3546static int
3547ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3548 struct ftrace_glob *mod_g, int exclude_mod)
3549{
3550 char str[KSYM_SYMBOL_LEN];
3551 char *modname;
3552
3553 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3554
3555 if (mod_g) {
3556 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3557
3558 /* blank module name to match all modules */
3559 if (!mod_g->len) {
3560 /* blank module globbing: modname xor exclude_mod */
3561 if ((!exclude_mod) != (!modname))
3562 goto func_match;
3563 return 0;
3564 }
3565
3566 /* not matching the module */
3567 if (!modname || !mod_matches) {
3568 if (exclude_mod)
3569 goto func_match;
3570 else
3571 return 0;
3572 }
3573
3574 if (mod_matches && exclude_mod)
3575 return 0;
3576
3577func_match:
3578 /* blank search means to match all funcs in the mod */
3579 if (!func_g->len)
3580 return 1;
3581 }
3582
3583 return ftrace_match(str, func_g);
3584}
3585
3586static int
3587match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3588{
3589 struct ftrace_page *pg;
3590 struct dyn_ftrace *rec;
3591 struct ftrace_glob func_g = { .type = MATCH_FULL };
3592 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3593 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3594 int exclude_mod = 0;
3595 int found = 0;
3596 int ret;
3597 int clear_filter;
3598
3599 if (func) {
3600 func_g.type = filter_parse_regex(func, len, &func_g.search,
3601 &clear_filter);
3602 func_g.len = strlen(func_g.search);
3603 }
3604
3605 if (mod) {
3606 mod_g.type = filter_parse_regex(mod, strlen(mod),
3607 &mod_g.search, &exclude_mod);
3608 mod_g.len = strlen(mod_g.search);
3609 }
3610
3611 mutex_lock(&ftrace_lock);
3612
3613 if (unlikely(ftrace_disabled))
3614 goto out_unlock;
3615
3616 do_for_each_ftrace_rec(pg, rec) {
3617
3618 if (rec->flags & FTRACE_FL_DISABLED)
3619 continue;
3620
3621 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3622 ret = enter_record(hash, rec, clear_filter);
3623 if (ret < 0) {
3624 found = ret;
3625 goto out_unlock;
3626 }
3627 found = 1;
3628 }
3629 } while_for_each_ftrace_rec();
3630 out_unlock:
3631 mutex_unlock(&ftrace_lock);
3632
3633 return found;
3634}
3635
3636static int
3637ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3638{
3639 return match_records(hash, buff, len, NULL);
3640}
3641
3642
3643/*
3644 * We register the module command as a template to show others how
3645 * to register the a command as well.
3646 */
3647
3648static int
3649ftrace_mod_callback(struct ftrace_hash *hash,
3650 char *func, char *cmd, char *module, int enable)
3651{
3652 int ret;
3653
3654 /*
3655 * cmd == 'mod' because we only registered this func
3656 * for the 'mod' ftrace_func_command.
3657 * But if you register one func with multiple commands,
3658 * you can tell which command was used by the cmd
3659 * parameter.
3660 */
3661 ret = match_records(hash, func, strlen(func), module);
3662 if (!ret)
3663 return -EINVAL;
3664 if (ret < 0)
3665 return ret;
3666 return 0;
3667}
3668
3669static struct ftrace_func_command ftrace_mod_cmd = {
3670 .name = "mod",
3671 .func = ftrace_mod_callback,
3672};
3673
3674static int __init ftrace_mod_cmd_init(void)
3675{
3676 return register_ftrace_command(&ftrace_mod_cmd);
3677}
3678core_initcall(ftrace_mod_cmd_init);
3679
3680static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3681 struct ftrace_ops *op, struct pt_regs *pt_regs)
3682{
3683 struct ftrace_func_probe *entry;
3684 struct hlist_head *hhd;
3685 unsigned long key;
3686
3687 key = hash_long(ip, FTRACE_HASH_BITS);
3688
3689 hhd = &ftrace_func_hash[key];
3690
3691 if (hlist_empty(hhd))
3692 return;
3693
3694 /*
3695 * Disable preemption for these calls to prevent a RCU grace
3696 * period. This syncs the hash iteration and freeing of items
3697 * on the hash. rcu_read_lock is too dangerous here.
3698 */
3699 preempt_disable_notrace();
3700 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3701 if (entry->ip == ip)
3702 entry->ops->func(ip, parent_ip, &entry->data);
3703 }
3704 preempt_enable_notrace();
3705}
3706
3707static struct ftrace_ops trace_probe_ops __read_mostly =
3708{
3709 .func = function_trace_probe_call,
3710 .flags = FTRACE_OPS_FL_INITIALIZED,
3711 INIT_OPS_HASH(trace_probe_ops)
3712};
3713
3714static int ftrace_probe_registered;
3715
3716static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3717{
3718 int ret;
3719 int i;
3720
3721 if (ftrace_probe_registered) {
3722 /* still need to update the function call sites */
3723 if (ftrace_enabled)
3724 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3725 old_hash);
3726 return;
3727 }
3728
3729 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3730 struct hlist_head *hhd = &ftrace_func_hash[i];
3731 if (hhd->first)
3732 break;
3733 }
3734 /* Nothing registered? */
3735 if (i == FTRACE_FUNC_HASHSIZE)
3736 return;
3737
3738 ret = ftrace_startup(&trace_probe_ops, 0);
3739
3740 ftrace_probe_registered = 1;
3741}
3742
3743static void __disable_ftrace_function_probe(void)
3744{
3745 int i;
3746
3747 if (!ftrace_probe_registered)
3748 return;
3749
3750 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3751 struct hlist_head *hhd = &ftrace_func_hash[i];
3752 if (hhd->first)
3753 return;
3754 }
3755
3756 /* no more funcs left */
3757 ftrace_shutdown(&trace_probe_ops, 0);
3758
3759 ftrace_probe_registered = 0;
3760}
3761
3762
3763static void ftrace_free_entry(struct ftrace_func_probe *entry)
3764{
3765 if (entry->ops->free)
3766 entry->ops->free(entry->ops, entry->ip, &entry->data);
3767 kfree(entry);
3768}
3769
3770int
3771register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3772 void *data)
3773{
3774 struct ftrace_ops_hash old_hash_ops;
3775 struct ftrace_func_probe *entry;
3776 struct ftrace_glob func_g;
3777 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3778 struct ftrace_hash *old_hash = *orig_hash;
3779 struct ftrace_hash *hash;
3780 struct ftrace_page *pg;
3781 struct dyn_ftrace *rec;
3782 int not;
3783 unsigned long key;
3784 int count = 0;
3785 int ret;
3786
3787 func_g.type = filter_parse_regex(glob, strlen(glob),
3788 &func_g.search, ¬);
3789 func_g.len = strlen(func_g.search);
3790
3791 /* we do not support '!' for function probes */
3792 if (WARN_ON(not))
3793 return -EINVAL;
3794
3795 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3796
3797 old_hash_ops.filter_hash = old_hash;
3798 /* Probes only have filters */
3799 old_hash_ops.notrace_hash = NULL;
3800
3801 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3802 if (!hash) {
3803 count = -ENOMEM;
3804 goto out;
3805 }
3806
3807 if (unlikely(ftrace_disabled)) {
3808 count = -ENODEV;
3809 goto out;
3810 }
3811
3812 mutex_lock(&ftrace_lock);
3813
3814 do_for_each_ftrace_rec(pg, rec) {
3815
3816 if (rec->flags & FTRACE_FL_DISABLED)
3817 continue;
3818
3819 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3820 continue;
3821
3822 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3823 if (!entry) {
3824 /* If we did not process any, then return error */
3825 if (!count)
3826 count = -ENOMEM;
3827 goto out_unlock;
3828 }
3829
3830 count++;
3831
3832 entry->data = data;
3833
3834 /*
3835 * The caller might want to do something special
3836 * for each function we find. We call the callback
3837 * to give the caller an opportunity to do so.
3838 */
3839 if (ops->init) {
3840 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3841 /* caller does not like this func */
3842 kfree(entry);
3843 continue;
3844 }
3845 }
3846
3847 ret = enter_record(hash, rec, 0);
3848 if (ret < 0) {
3849 kfree(entry);
3850 count = ret;
3851 goto out_unlock;
3852 }
3853
3854 entry->ops = ops;
3855 entry->ip = rec->ip;
3856
3857 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3858 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3859
3860 } while_for_each_ftrace_rec();
3861
3862 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3863
3864 __enable_ftrace_function_probe(&old_hash_ops);
3865
3866 if (!ret)
3867 free_ftrace_hash_rcu(old_hash);
3868 else
3869 count = ret;
3870
3871 out_unlock:
3872 mutex_unlock(&ftrace_lock);
3873 out:
3874 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3875 free_ftrace_hash(hash);
3876
3877 return count;
3878}
3879
3880enum {
3881 PROBE_TEST_FUNC = 1,
3882 PROBE_TEST_DATA = 2
3883};
3884
3885static void
3886__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3887 void *data, int flags)
3888{
3889 struct ftrace_func_entry *rec_entry;
3890 struct ftrace_func_probe *entry;
3891 struct ftrace_func_probe *p;
3892 struct ftrace_glob func_g;
3893 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3894 struct ftrace_hash *old_hash = *orig_hash;
3895 struct list_head free_list;
3896 struct ftrace_hash *hash;
3897 struct hlist_node *tmp;
3898 char str[KSYM_SYMBOL_LEN];
3899 int i, ret;
3900
3901 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3902 func_g.search = NULL;
3903 else if (glob) {
3904 int not;
3905
3906 func_g.type = filter_parse_regex(glob, strlen(glob),
3907 &func_g.search, ¬);
3908 func_g.len = strlen(func_g.search);
3909 func_g.search = glob;
3910
3911 /* we do not support '!' for function probes */
3912 if (WARN_ON(not))
3913 return;
3914 }
3915
3916 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3917
3918 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3919 if (!hash)
3920 /* Hmm, should report this somehow */
3921 goto out_unlock;
3922
3923 INIT_LIST_HEAD(&free_list);
3924
3925 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3926 struct hlist_head *hhd = &ftrace_func_hash[i];
3927
3928 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3929
3930 /* break up if statements for readability */
3931 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3932 continue;
3933
3934 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3935 continue;
3936
3937 /* do this last, since it is the most expensive */
3938 if (func_g.search) {
3939 kallsyms_lookup(entry->ip, NULL, NULL,
3940 NULL, str);
3941 if (!ftrace_match(str, &func_g))
3942 continue;
3943 }
3944
3945 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3946 /* It is possible more than one entry had this ip */
3947 if (rec_entry)
3948 free_hash_entry(hash, rec_entry);
3949
3950 hlist_del_rcu(&entry->node);
3951 list_add(&entry->free_list, &free_list);
3952 }
3953 }
3954 mutex_lock(&ftrace_lock);
3955 __disable_ftrace_function_probe();
3956 /*
3957 * Remove after the disable is called. Otherwise, if the last
3958 * probe is removed, a null hash means *all enabled*.
3959 */
3960 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3961 synchronize_sched();
3962 if (!ret)
3963 free_ftrace_hash_rcu(old_hash);
3964
3965 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3966 list_del(&entry->free_list);
3967 ftrace_free_entry(entry);
3968 }
3969 mutex_unlock(&ftrace_lock);
3970
3971 out_unlock:
3972 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3973 free_ftrace_hash(hash);
3974}
3975
3976void
3977unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3978 void *data)
3979{
3980 __unregister_ftrace_function_probe(glob, ops, data,
3981 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3982}
3983
3984void
3985unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3986{
3987 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3988}
3989
3990void unregister_ftrace_function_probe_all(char *glob)
3991{
3992 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3993}
3994
3995static LIST_HEAD(ftrace_commands);
3996static DEFINE_MUTEX(ftrace_cmd_mutex);
3997
3998/*
3999 * Currently we only register ftrace commands from __init, so mark this
4000 * __init too.
4001 */
4002__init int register_ftrace_command(struct ftrace_func_command *cmd)
4003{
4004 struct ftrace_func_command *p;
4005 int ret = 0;
4006
4007 mutex_lock(&ftrace_cmd_mutex);
4008 list_for_each_entry(p, &ftrace_commands, list) {
4009 if (strcmp(cmd->name, p->name) == 0) {
4010 ret = -EBUSY;
4011 goto out_unlock;
4012 }
4013 }
4014 list_add(&cmd->list, &ftrace_commands);
4015 out_unlock:
4016 mutex_unlock(&ftrace_cmd_mutex);
4017
4018 return ret;
4019}
4020
4021/*
4022 * Currently we only unregister ftrace commands from __init, so mark
4023 * this __init too.
4024 */
4025__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4026{
4027 struct ftrace_func_command *p, *n;
4028 int ret = -ENODEV;
4029
4030 mutex_lock(&ftrace_cmd_mutex);
4031 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4032 if (strcmp(cmd->name, p->name) == 0) {
4033 ret = 0;
4034 list_del_init(&p->list);
4035 goto out_unlock;
4036 }
4037 }
4038 out_unlock:
4039 mutex_unlock(&ftrace_cmd_mutex);
4040
4041 return ret;
4042}
4043
4044static int ftrace_process_regex(struct ftrace_hash *hash,
4045 char *buff, int len, int enable)
4046{
4047 char *func, *command, *next = buff;
4048 struct ftrace_func_command *p;
4049 int ret = -EINVAL;
4050
4051 func = strsep(&next, ":");
4052
4053 if (!next) {
4054 ret = ftrace_match_records(hash, func, len);
4055 if (!ret)
4056 ret = -EINVAL;
4057 if (ret < 0)
4058 return ret;
4059 return 0;
4060 }
4061
4062 /* command found */
4063
4064 command = strsep(&next, ":");
4065
4066 mutex_lock(&ftrace_cmd_mutex);
4067 list_for_each_entry(p, &ftrace_commands, list) {
4068 if (strcmp(p->name, command) == 0) {
4069 ret = p->func(hash, func, command, next, enable);
4070 goto out_unlock;
4071 }
4072 }
4073 out_unlock:
4074 mutex_unlock(&ftrace_cmd_mutex);
4075
4076 return ret;
4077}
4078
4079static ssize_t
4080ftrace_regex_write(struct file *file, const char __user *ubuf,
4081 size_t cnt, loff_t *ppos, int enable)
4082{
4083 struct ftrace_iterator *iter;
4084 struct trace_parser *parser;
4085 ssize_t ret, read;
4086
4087 if (!cnt)
4088 return 0;
4089
4090 if (file->f_mode & FMODE_READ) {
4091 struct seq_file *m = file->private_data;
4092 iter = m->private;
4093 } else
4094 iter = file->private_data;
4095
4096 if (unlikely(ftrace_disabled))
4097 return -ENODEV;
4098
4099 /* iter->hash is a local copy, so we don't need regex_lock */
4100
4101 parser = &iter->parser;
4102 read = trace_get_user(parser, ubuf, cnt, ppos);
4103
4104 if (read >= 0 && trace_parser_loaded(parser) &&
4105 !trace_parser_cont(parser)) {
4106 ret = ftrace_process_regex(iter->hash, parser->buffer,
4107 parser->idx, enable);
4108 trace_parser_clear(parser);
4109 if (ret < 0)
4110 goto out;
4111 }
4112
4113 ret = read;
4114 out:
4115 return ret;
4116}
4117
4118ssize_t
4119ftrace_filter_write(struct file *file, const char __user *ubuf,
4120 size_t cnt, loff_t *ppos)
4121{
4122 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4123}
4124
4125ssize_t
4126ftrace_notrace_write(struct file *file, const char __user *ubuf,
4127 size_t cnt, loff_t *ppos)
4128{
4129 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4130}
4131
4132static int
4133ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4134{
4135 struct ftrace_func_entry *entry;
4136
4137 if (!ftrace_location(ip))
4138 return -EINVAL;
4139
4140 if (remove) {
4141 entry = ftrace_lookup_ip(hash, ip);
4142 if (!entry)
4143 return -ENOENT;
4144 free_hash_entry(hash, entry);
4145 return 0;
4146 }
4147
4148 return add_hash_entry(hash, ip);
4149}
4150
4151static void ftrace_ops_update_code(struct ftrace_ops *ops,
4152 struct ftrace_ops_hash *old_hash)
4153{
4154 struct ftrace_ops *op;
4155
4156 if (!ftrace_enabled)
4157 return;
4158
4159 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4160 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4161 return;
4162 }
4163
4164 /*
4165 * If this is the shared global_ops filter, then we need to
4166 * check if there is another ops that shares it, is enabled.
4167 * If so, we still need to run the modify code.
4168 */
4169 if (ops->func_hash != &global_ops.local_hash)
4170 return;
4171
4172 do_for_each_ftrace_op(op, ftrace_ops_list) {
4173 if (op->func_hash == &global_ops.local_hash &&
4174 op->flags & FTRACE_OPS_FL_ENABLED) {
4175 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4176 /* Only need to do this once */
4177 return;
4178 }
4179 } while_for_each_ftrace_op(op);
4180}
4181
4182static int
4183ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4184 unsigned long ip, int remove, int reset, int enable)
4185{
4186 struct ftrace_hash **orig_hash;
4187 struct ftrace_ops_hash old_hash_ops;
4188 struct ftrace_hash *old_hash;
4189 struct ftrace_hash *hash;
4190 int ret;
4191
4192 if (unlikely(ftrace_disabled))
4193 return -ENODEV;
4194
4195 mutex_lock(&ops->func_hash->regex_lock);
4196
4197 if (enable)
4198 orig_hash = &ops->func_hash->filter_hash;
4199 else
4200 orig_hash = &ops->func_hash->notrace_hash;
4201
4202 if (reset)
4203 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4204 else
4205 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4206
4207 if (!hash) {
4208 ret = -ENOMEM;
4209 goto out_regex_unlock;
4210 }
4211
4212 if (buf && !ftrace_match_records(hash, buf, len)) {
4213 ret = -EINVAL;
4214 goto out_regex_unlock;
4215 }
4216 if (ip) {
4217 ret = ftrace_match_addr(hash, ip, remove);
4218 if (ret < 0)
4219 goto out_regex_unlock;
4220 }
4221
4222 mutex_lock(&ftrace_lock);
4223 old_hash = *orig_hash;
4224 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4225 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4226 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4227 if (!ret) {
4228 ftrace_ops_update_code(ops, &old_hash_ops);
4229 free_ftrace_hash_rcu(old_hash);
4230 }
4231 mutex_unlock(&ftrace_lock);
4232
4233 out_regex_unlock:
4234 mutex_unlock(&ops->func_hash->regex_lock);
4235
4236 free_ftrace_hash(hash);
4237 return ret;
4238}
4239
4240static int
4241ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4242 int reset, int enable)
4243{
4244 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4245}
4246
4247/**
4248 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4249 * @ops - the ops to set the filter with
4250 * @ip - the address to add to or remove from the filter.
4251 * @remove - non zero to remove the ip from the filter
4252 * @reset - non zero to reset all filters before applying this filter.
4253 *
4254 * Filters denote which functions should be enabled when tracing is enabled
4255 * If @ip is NULL, it failes to update filter.
4256 */
4257int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4258 int remove, int reset)
4259{
4260 ftrace_ops_init(ops);
4261 return ftrace_set_addr(ops, ip, remove, reset, 1);
4262}
4263EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4264
4265/**
4266 * ftrace_ops_set_global_filter - setup ops to use global filters
4267 * @ops - the ops which will use the global filters
4268 *
4269 * ftrace users who need global function trace filtering should call this.
4270 * It can set the global filter only if ops were not initialized before.
4271 */
4272void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4273{
4274 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4275 return;
4276
4277 ftrace_ops_init(ops);
4278 ops->func_hash = &global_ops.local_hash;
4279}
4280EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4281
4282static int
4283ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4284 int reset, int enable)
4285{
4286 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4287}
4288
4289/**
4290 * ftrace_set_filter - set a function to filter on in ftrace
4291 * @ops - the ops to set the filter with
4292 * @buf - the string that holds the function filter text.
4293 * @len - the length of the string.
4294 * @reset - non zero to reset all filters before applying this filter.
4295 *
4296 * Filters denote which functions should be enabled when tracing is enabled.
4297 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4298 */
4299int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4300 int len, int reset)
4301{
4302 ftrace_ops_init(ops);
4303 return ftrace_set_regex(ops, buf, len, reset, 1);
4304}
4305EXPORT_SYMBOL_GPL(ftrace_set_filter);
4306
4307/**
4308 * ftrace_set_notrace - set a function to not trace in ftrace
4309 * @ops - the ops to set the notrace filter with
4310 * @buf - the string that holds the function notrace text.
4311 * @len - the length of the string.
4312 * @reset - non zero to reset all filters before applying this filter.
4313 *
4314 * Notrace Filters denote which functions should not be enabled when tracing
4315 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4316 * for tracing.
4317 */
4318int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4319 int len, int reset)
4320{
4321 ftrace_ops_init(ops);
4322 return ftrace_set_regex(ops, buf, len, reset, 0);
4323}
4324EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4325/**
4326 * ftrace_set_global_filter - set a function to filter on with global tracers
4327 * @buf - the string that holds the function filter text.
4328 * @len - the length of the string.
4329 * @reset - non zero to reset all filters before applying this filter.
4330 *
4331 * Filters denote which functions should be enabled when tracing is enabled.
4332 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4333 */
4334void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4335{
4336 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4337}
4338EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4339
4340/**
4341 * ftrace_set_global_notrace - set a function to not trace with global tracers
4342 * @buf - the string that holds the function notrace text.
4343 * @len - the length of the string.
4344 * @reset - non zero to reset all filters before applying this filter.
4345 *
4346 * Notrace Filters denote which functions should not be enabled when tracing
4347 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4348 * for tracing.
4349 */
4350void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4351{
4352 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4353}
4354EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4355
4356/*
4357 * command line interface to allow users to set filters on boot up.
4358 */
4359#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4360static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4361static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4362
4363/* Used by function selftest to not test if filter is set */
4364bool ftrace_filter_param __initdata;
4365
4366static int __init set_ftrace_notrace(char *str)
4367{
4368 ftrace_filter_param = true;
4369 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4370 return 1;
4371}
4372__setup("ftrace_notrace=", set_ftrace_notrace);
4373
4374static int __init set_ftrace_filter(char *str)
4375{
4376 ftrace_filter_param = true;
4377 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4378 return 1;
4379}
4380__setup("ftrace_filter=", set_ftrace_filter);
4381
4382#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4383static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4384static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4385static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4386
4387static unsigned long save_global_trampoline;
4388static unsigned long save_global_flags;
4389
4390static int __init set_graph_function(char *str)
4391{
4392 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4393 return 1;
4394}
4395__setup("ftrace_graph_filter=", set_graph_function);
4396
4397static int __init set_graph_notrace_function(char *str)
4398{
4399 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4400 return 1;
4401}
4402__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4403
4404static void __init set_ftrace_early_graph(char *buf, int enable)
4405{
4406 int ret;
4407 char *func;
4408 unsigned long *table = ftrace_graph_funcs;
4409 int *count = &ftrace_graph_count;
4410
4411 if (!enable) {
4412 table = ftrace_graph_notrace_funcs;
4413 count = &ftrace_graph_notrace_count;
4414 }
4415
4416 while (buf) {
4417 func = strsep(&buf, ",");
4418 /* we allow only one expression at a time */
4419 ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4420 if (ret)
4421 printk(KERN_DEBUG "ftrace: function %s not "
4422 "traceable\n", func);
4423 }
4424}
4425#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4426
4427void __init
4428ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4429{
4430 char *func;
4431
4432 ftrace_ops_init(ops);
4433
4434 while (buf) {
4435 func = strsep(&buf, ",");
4436 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4437 }
4438}
4439
4440static void __init set_ftrace_early_filters(void)
4441{
4442 if (ftrace_filter_buf[0])
4443 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4444 if (ftrace_notrace_buf[0])
4445 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4446#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4447 if (ftrace_graph_buf[0])
4448 set_ftrace_early_graph(ftrace_graph_buf, 1);
4449 if (ftrace_graph_notrace_buf[0])
4450 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4451#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4452}
4453
4454int ftrace_regex_release(struct inode *inode, struct file *file)
4455{
4456 struct seq_file *m = (struct seq_file *)file->private_data;
4457 struct ftrace_ops_hash old_hash_ops;
4458 struct ftrace_iterator *iter;
4459 struct ftrace_hash **orig_hash;
4460 struct ftrace_hash *old_hash;
4461 struct trace_parser *parser;
4462 int filter_hash;
4463 int ret;
4464
4465 if (file->f_mode & FMODE_READ) {
4466 iter = m->private;
4467 seq_release(inode, file);
4468 } else
4469 iter = file->private_data;
4470
4471 parser = &iter->parser;
4472 if (trace_parser_loaded(parser)) {
4473 parser->buffer[parser->idx] = 0;
4474 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4475 }
4476
4477 trace_parser_put(parser);
4478
4479 mutex_lock(&iter->ops->func_hash->regex_lock);
4480
4481 if (file->f_mode & FMODE_WRITE) {
4482 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4483
4484 if (filter_hash)
4485 orig_hash = &iter->ops->func_hash->filter_hash;
4486 else
4487 orig_hash = &iter->ops->func_hash->notrace_hash;
4488
4489 mutex_lock(&ftrace_lock);
4490 old_hash = *orig_hash;
4491 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4492 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4493 ret = ftrace_hash_move(iter->ops, filter_hash,
4494 orig_hash, iter->hash);
4495 if (!ret) {
4496 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4497 free_ftrace_hash_rcu(old_hash);
4498 }
4499 mutex_unlock(&ftrace_lock);
4500 }
4501
4502 mutex_unlock(&iter->ops->func_hash->regex_lock);
4503 free_ftrace_hash(iter->hash);
4504 kfree(iter);
4505
4506 return 0;
4507}
4508
4509static const struct file_operations ftrace_avail_fops = {
4510 .open = ftrace_avail_open,
4511 .read = seq_read,
4512 .llseek = seq_lseek,
4513 .release = seq_release_private,
4514};
4515
4516static const struct file_operations ftrace_enabled_fops = {
4517 .open = ftrace_enabled_open,
4518 .read = seq_read,
4519 .llseek = seq_lseek,
4520 .release = seq_release_private,
4521};
4522
4523static const struct file_operations ftrace_filter_fops = {
4524 .open = ftrace_filter_open,
4525 .read = seq_read,
4526 .write = ftrace_filter_write,
4527 .llseek = tracing_lseek,
4528 .release = ftrace_regex_release,
4529};
4530
4531static const struct file_operations ftrace_notrace_fops = {
4532 .open = ftrace_notrace_open,
4533 .read = seq_read,
4534 .write = ftrace_notrace_write,
4535 .llseek = tracing_lseek,
4536 .release = ftrace_regex_release,
4537};
4538
4539#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4540
4541static DEFINE_MUTEX(graph_lock);
4542
4543int ftrace_graph_count;
4544int ftrace_graph_notrace_count;
4545unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4546unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4547
4548struct ftrace_graph_data {
4549 unsigned long *table;
4550 size_t size;
4551 int *count;
4552 const struct seq_operations *seq_ops;
4553};
4554
4555static void *
4556__g_next(struct seq_file *m, loff_t *pos)
4557{
4558 struct ftrace_graph_data *fgd = m->private;
4559
4560 if (*pos >= *fgd->count)
4561 return NULL;
4562 return &fgd->table[*pos];
4563}
4564
4565static void *
4566g_next(struct seq_file *m, void *v, loff_t *pos)
4567{
4568 (*pos)++;
4569 return __g_next(m, pos);
4570}
4571
4572static void *g_start(struct seq_file *m, loff_t *pos)
4573{
4574 struct ftrace_graph_data *fgd = m->private;
4575
4576 mutex_lock(&graph_lock);
4577
4578 /* Nothing, tell g_show to print all functions are enabled */
4579 if (!*fgd->count && !*pos)
4580 return (void *)1;
4581
4582 return __g_next(m, pos);
4583}
4584
4585static void g_stop(struct seq_file *m, void *p)
4586{
4587 mutex_unlock(&graph_lock);
4588}
4589
4590static int g_show(struct seq_file *m, void *v)
4591{
4592 unsigned long *ptr = v;
4593
4594 if (!ptr)
4595 return 0;
4596
4597 if (ptr == (unsigned long *)1) {
4598 struct ftrace_graph_data *fgd = m->private;
4599
4600 if (fgd->table == ftrace_graph_funcs)
4601 seq_puts(m, "#### all functions enabled ####\n");
4602 else
4603 seq_puts(m, "#### no functions disabled ####\n");
4604 return 0;
4605 }
4606
4607 seq_printf(m, "%ps\n", (void *)*ptr);
4608
4609 return 0;
4610}
4611
4612static const struct seq_operations ftrace_graph_seq_ops = {
4613 .start = g_start,
4614 .next = g_next,
4615 .stop = g_stop,
4616 .show = g_show,
4617};
4618
4619static int
4620__ftrace_graph_open(struct inode *inode, struct file *file,
4621 struct ftrace_graph_data *fgd)
4622{
4623 int ret = 0;
4624
4625 mutex_lock(&graph_lock);
4626 if ((file->f_mode & FMODE_WRITE) &&
4627 (file->f_flags & O_TRUNC)) {
4628 *fgd->count = 0;
4629 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4630 }
4631 mutex_unlock(&graph_lock);
4632
4633 if (file->f_mode & FMODE_READ) {
4634 ret = seq_open(file, fgd->seq_ops);
4635 if (!ret) {
4636 struct seq_file *m = file->private_data;
4637 m->private = fgd;
4638 }
4639 } else
4640 file->private_data = fgd;
4641
4642 return ret;
4643}
4644
4645static int
4646ftrace_graph_open(struct inode *inode, struct file *file)
4647{
4648 struct ftrace_graph_data *fgd;
4649
4650 if (unlikely(ftrace_disabled))
4651 return -ENODEV;
4652
4653 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4654 if (fgd == NULL)
4655 return -ENOMEM;
4656
4657 fgd->table = ftrace_graph_funcs;
4658 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4659 fgd->count = &ftrace_graph_count;
4660 fgd->seq_ops = &ftrace_graph_seq_ops;
4661
4662 return __ftrace_graph_open(inode, file, fgd);
4663}
4664
4665static int
4666ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4667{
4668 struct ftrace_graph_data *fgd;
4669
4670 if (unlikely(ftrace_disabled))
4671 return -ENODEV;
4672
4673 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4674 if (fgd == NULL)
4675 return -ENOMEM;
4676
4677 fgd->table = ftrace_graph_notrace_funcs;
4678 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4679 fgd->count = &ftrace_graph_notrace_count;
4680 fgd->seq_ops = &ftrace_graph_seq_ops;
4681
4682 return __ftrace_graph_open(inode, file, fgd);
4683}
4684
4685static int
4686ftrace_graph_release(struct inode *inode, struct file *file)
4687{
4688 if (file->f_mode & FMODE_READ) {
4689 struct seq_file *m = file->private_data;
4690
4691 kfree(m->private);
4692 seq_release(inode, file);
4693 } else {
4694 kfree(file->private_data);
4695 }
4696
4697 return 0;
4698}
4699
4700static int
4701ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4702{
4703 struct ftrace_glob func_g;
4704 struct dyn_ftrace *rec;
4705 struct ftrace_page *pg;
4706 int fail = 1;
4707 int not;
4708 bool exists;
4709 int i;
4710
4711 /* decode regex */
4712 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4713 &func_g.search, ¬);
4714 if (!not && *idx >= size)
4715 return -EBUSY;
4716
4717 func_g.len = strlen(func_g.search);
4718
4719 mutex_lock(&ftrace_lock);
4720
4721 if (unlikely(ftrace_disabled)) {
4722 mutex_unlock(&ftrace_lock);
4723 return -ENODEV;
4724 }
4725
4726 do_for_each_ftrace_rec(pg, rec) {
4727
4728 if (rec->flags & FTRACE_FL_DISABLED)
4729 continue;
4730
4731 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4732 /* if it is in the array */
4733 exists = false;
4734 for (i = 0; i < *idx; i++) {
4735 if (array[i] == rec->ip) {
4736 exists = true;
4737 break;
4738 }
4739 }
4740
4741 if (!not) {
4742 fail = 0;
4743 if (!exists) {
4744 array[(*idx)++] = rec->ip;
4745 if (*idx >= size)
4746 goto out;
4747 }
4748 } else {
4749 if (exists) {
4750 array[i] = array[--(*idx)];
4751 array[*idx] = 0;
4752 fail = 0;
4753 }
4754 }
4755 }
4756 } while_for_each_ftrace_rec();
4757out:
4758 mutex_unlock(&ftrace_lock);
4759
4760 if (fail)
4761 return -EINVAL;
4762
4763 return 0;
4764}
4765
4766static ssize_t
4767ftrace_graph_write(struct file *file, const char __user *ubuf,
4768 size_t cnt, loff_t *ppos)
4769{
4770 struct trace_parser parser;
4771 ssize_t read, ret = 0;
4772 struct ftrace_graph_data *fgd = file->private_data;
4773
4774 if (!cnt)
4775 return 0;
4776
4777 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4778 return -ENOMEM;
4779
4780 read = trace_get_user(&parser, ubuf, cnt, ppos);
4781
4782 if (read >= 0 && trace_parser_loaded((&parser))) {
4783 parser.buffer[parser.idx] = 0;
4784
4785 mutex_lock(&graph_lock);
4786
4787 /* we allow only one expression at a time */
4788 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4789 parser.buffer);
4790
4791 mutex_unlock(&graph_lock);
4792 }
4793
4794 if (!ret)
4795 ret = read;
4796
4797 trace_parser_put(&parser);
4798
4799 return ret;
4800}
4801
4802static const struct file_operations ftrace_graph_fops = {
4803 .open = ftrace_graph_open,
4804 .read = seq_read,
4805 .write = ftrace_graph_write,
4806 .llseek = tracing_lseek,
4807 .release = ftrace_graph_release,
4808};
4809
4810static const struct file_operations ftrace_graph_notrace_fops = {
4811 .open = ftrace_graph_notrace_open,
4812 .read = seq_read,
4813 .write = ftrace_graph_write,
4814 .llseek = tracing_lseek,
4815 .release = ftrace_graph_release,
4816};
4817#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4818
4819void ftrace_create_filter_files(struct ftrace_ops *ops,
4820 struct dentry *parent)
4821{
4822
4823 trace_create_file("set_ftrace_filter", 0644, parent,
4824 ops, &ftrace_filter_fops);
4825
4826 trace_create_file("set_ftrace_notrace", 0644, parent,
4827 ops, &ftrace_notrace_fops);
4828}
4829
4830/*
4831 * The name "destroy_filter_files" is really a misnomer. Although
4832 * in the future, it may actualy delete the files, but this is
4833 * really intended to make sure the ops passed in are disabled
4834 * and that when this function returns, the caller is free to
4835 * free the ops.
4836 *
4837 * The "destroy" name is only to match the "create" name that this
4838 * should be paired with.
4839 */
4840void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4841{
4842 mutex_lock(&ftrace_lock);
4843 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4844 ftrace_shutdown(ops, 0);
4845 ops->flags |= FTRACE_OPS_FL_DELETED;
4846 mutex_unlock(&ftrace_lock);
4847}
4848
4849static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4850{
4851
4852 trace_create_file("available_filter_functions", 0444,
4853 d_tracer, NULL, &ftrace_avail_fops);
4854
4855 trace_create_file("enabled_functions", 0444,
4856 d_tracer, NULL, &ftrace_enabled_fops);
4857
4858 ftrace_create_filter_files(&global_ops, d_tracer);
4859
4860#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4861 trace_create_file("set_graph_function", 0444, d_tracer,
4862 NULL,
4863 &ftrace_graph_fops);
4864 trace_create_file("set_graph_notrace", 0444, d_tracer,
4865 NULL,
4866 &ftrace_graph_notrace_fops);
4867#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4868
4869 return 0;
4870}
4871
4872static int ftrace_cmp_ips(const void *a, const void *b)
4873{
4874 const unsigned long *ipa = a;
4875 const unsigned long *ipb = b;
4876
4877 if (*ipa > *ipb)
4878 return 1;
4879 if (*ipa < *ipb)
4880 return -1;
4881 return 0;
4882}
4883
4884static int ftrace_process_locs(struct module *mod,
4885 unsigned long *start,
4886 unsigned long *end)
4887{
4888 struct ftrace_page *start_pg;
4889 struct ftrace_page *pg;
4890 struct dyn_ftrace *rec;
4891 unsigned long count;
4892 unsigned long *p;
4893 unsigned long addr;
4894 unsigned long flags = 0; /* Shut up gcc */
4895 int ret = -ENOMEM;
4896
4897 count = end - start;
4898
4899 if (!count)
4900 return 0;
4901
4902 sort(start, count, sizeof(*start),
4903 ftrace_cmp_ips, NULL);
4904
4905 start_pg = ftrace_allocate_pages(count);
4906 if (!start_pg)
4907 return -ENOMEM;
4908
4909 mutex_lock(&ftrace_lock);
4910
4911 /*
4912 * Core and each module needs their own pages, as
4913 * modules will free them when they are removed.
4914 * Force a new page to be allocated for modules.
4915 */
4916 if (!mod) {
4917 WARN_ON(ftrace_pages || ftrace_pages_start);
4918 /* First initialization */
4919 ftrace_pages = ftrace_pages_start = start_pg;
4920 } else {
4921 if (!ftrace_pages)
4922 goto out;
4923
4924 if (WARN_ON(ftrace_pages->next)) {
4925 /* Hmm, we have free pages? */
4926 while (ftrace_pages->next)
4927 ftrace_pages = ftrace_pages->next;
4928 }
4929
4930 ftrace_pages->next = start_pg;
4931 }
4932
4933 p = start;
4934 pg = start_pg;
4935 while (p < end) {
4936 addr = ftrace_call_adjust(*p++);
4937 /*
4938 * Some architecture linkers will pad between
4939 * the different mcount_loc sections of different
4940 * object files to satisfy alignments.
4941 * Skip any NULL pointers.
4942 */
4943 if (!addr)
4944 continue;
4945
4946 if (pg->index == pg->size) {
4947 /* We should have allocated enough */
4948 if (WARN_ON(!pg->next))
4949 break;
4950 pg = pg->next;
4951 }
4952
4953 rec = &pg->records[pg->index++];
4954 rec->ip = addr;
4955 }
4956
4957 /* We should have used all pages */
4958 WARN_ON(pg->next);
4959
4960 /* Assign the last page to ftrace_pages */
4961 ftrace_pages = pg;
4962
4963 /*
4964 * We only need to disable interrupts on start up
4965 * because we are modifying code that an interrupt
4966 * may execute, and the modification is not atomic.
4967 * But for modules, nothing runs the code we modify
4968 * until we are finished with it, and there's no
4969 * reason to cause large interrupt latencies while we do it.
4970 */
4971 if (!mod)
4972 local_irq_save(flags);
4973 ftrace_update_code(mod, start_pg);
4974 if (!mod)
4975 local_irq_restore(flags);
4976 ret = 0;
4977 out:
4978 mutex_unlock(&ftrace_lock);
4979
4980 return ret;
4981}
4982
4983#ifdef CONFIG_MODULES
4984
4985#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4986
4987static int referenced_filters(struct dyn_ftrace *rec)
4988{
4989 struct ftrace_ops *ops;
4990 int cnt = 0;
4991
4992 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
4993 if (ops_references_rec(ops, rec))
4994 cnt++;
4995 }
4996
4997 return cnt;
4998}
4999
5000void ftrace_release_mod(struct module *mod)
5001{
5002 struct dyn_ftrace *rec;
5003 struct ftrace_page **last_pg;
5004 struct ftrace_page *pg;
5005 int order;
5006
5007 mutex_lock(&ftrace_lock);
5008
5009 if (ftrace_disabled)
5010 goto out_unlock;
5011
5012 /*
5013 * Each module has its own ftrace_pages, remove
5014 * them from the list.
5015 */
5016 last_pg = &ftrace_pages_start;
5017 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5018 rec = &pg->records[0];
5019 if (within_module_core(rec->ip, mod)) {
5020 /*
5021 * As core pages are first, the first
5022 * page should never be a module page.
5023 */
5024 if (WARN_ON(pg == ftrace_pages_start))
5025 goto out_unlock;
5026
5027 /* Check if we are deleting the last page */
5028 if (pg == ftrace_pages)
5029 ftrace_pages = next_to_ftrace_page(last_pg);
5030
5031 *last_pg = pg->next;
5032 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5033 free_pages((unsigned long)pg->records, order);
5034 kfree(pg);
5035 } else
5036 last_pg = &pg->next;
5037 }
5038 out_unlock:
5039 mutex_unlock(&ftrace_lock);
5040}
5041
5042void ftrace_module_enable(struct module *mod)
5043{
5044 struct dyn_ftrace *rec;
5045 struct ftrace_page *pg;
5046
5047 mutex_lock(&ftrace_lock);
5048
5049 if (ftrace_disabled)
5050 goto out_unlock;
5051
5052 /*
5053 * If the tracing is enabled, go ahead and enable the record.
5054 *
5055 * The reason not to enable the record immediatelly is the
5056 * inherent check of ftrace_make_nop/ftrace_make_call for
5057 * correct previous instructions. Making first the NOP
5058 * conversion puts the module to the correct state, thus
5059 * passing the ftrace_make_call check.
5060 *
5061 * We also delay this to after the module code already set the
5062 * text to read-only, as we now need to set it back to read-write
5063 * so that we can modify the text.
5064 */
5065 if (ftrace_start_up)
5066 ftrace_arch_code_modify_prepare();
5067
5068 do_for_each_ftrace_rec(pg, rec) {
5069 int cnt;
5070 /*
5071 * do_for_each_ftrace_rec() is a double loop.
5072 * module text shares the pg. If a record is
5073 * not part of this module, then skip this pg,
5074 * which the "break" will do.
5075 */
5076 if (!within_module_core(rec->ip, mod))
5077 break;
5078
5079 cnt = 0;
5080
5081 /*
5082 * When adding a module, we need to check if tracers are
5083 * currently enabled and if they are, and can trace this record,
5084 * we need to enable the module functions as well as update the
5085 * reference counts for those function records.
5086 */
5087 if (ftrace_start_up)
5088 cnt += referenced_filters(rec);
5089
5090 /* This clears FTRACE_FL_DISABLED */
5091 rec->flags = cnt;
5092
5093 if (ftrace_start_up && cnt) {
5094 int failed = __ftrace_replace_code(rec, 1);
5095 if (failed) {
5096 ftrace_bug(failed, rec);
5097 goto out_loop;
5098 }
5099 }
5100
5101 } while_for_each_ftrace_rec();
5102
5103 out_loop:
5104 if (ftrace_start_up)
5105 ftrace_arch_code_modify_post_process();
5106
5107 out_unlock:
5108 mutex_unlock(&ftrace_lock);
5109}
5110
5111void ftrace_module_init(struct module *mod)
5112{
5113 if (ftrace_disabled || !mod->num_ftrace_callsites)
5114 return;
5115
5116 ftrace_process_locs(mod, mod->ftrace_callsites,
5117 mod->ftrace_callsites + mod->num_ftrace_callsites);
5118}
5119#endif /* CONFIG_MODULES */
5120
5121void __init ftrace_init(void)
5122{
5123 extern unsigned long __start_mcount_loc[];
5124 extern unsigned long __stop_mcount_loc[];
5125 unsigned long count, flags;
5126 int ret;
5127
5128 local_irq_save(flags);
5129 ret = ftrace_dyn_arch_init();
5130 local_irq_restore(flags);
5131 if (ret)
5132 goto failed;
5133
5134 count = __stop_mcount_loc - __start_mcount_loc;
5135 if (!count) {
5136 pr_info("ftrace: No functions to be traced?\n");
5137 goto failed;
5138 }
5139
5140 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5141 count, count / ENTRIES_PER_PAGE + 1);
5142
5143 last_ftrace_enabled = ftrace_enabled = 1;
5144
5145 ret = ftrace_process_locs(NULL,
5146 __start_mcount_loc,
5147 __stop_mcount_loc);
5148
5149 set_ftrace_early_filters();
5150
5151 return;
5152 failed:
5153 ftrace_disabled = 1;
5154}
5155
5156/* Do nothing if arch does not support this */
5157void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5158{
5159}
5160
5161static void ftrace_update_trampoline(struct ftrace_ops *ops)
5162{
5163
5164/*
5165 * Currently there's no safe way to free a trampoline when the kernel
5166 * is configured with PREEMPT. That is because a task could be preempted
5167 * when it jumped to the trampoline, it may be preempted for a long time
5168 * depending on the system load, and currently there's no way to know
5169 * when it will be off the trampoline. If the trampoline is freed
5170 * too early, when the task runs again, it will be executing on freed
5171 * memory and crash.
5172 */
5173#ifdef CONFIG_PREEMPT
5174 /* Currently, only non dynamic ops can have a trampoline */
5175 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5176 return;
5177#endif
5178
5179 arch_ftrace_update_trampoline(ops);
5180}
5181
5182#else
5183
5184static struct ftrace_ops global_ops = {
5185 .func = ftrace_stub,
5186 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5187 FTRACE_OPS_FL_INITIALIZED |
5188 FTRACE_OPS_FL_PID,
5189};
5190
5191static int __init ftrace_nodyn_init(void)
5192{
5193 ftrace_enabled = 1;
5194 return 0;
5195}
5196core_initcall(ftrace_nodyn_init);
5197
5198static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5199static inline void ftrace_startup_enable(int command) { }
5200static inline void ftrace_startup_all(int command) { }
5201/* Keep as macros so we do not need to define the commands */
5202# define ftrace_startup(ops, command) \
5203 ({ \
5204 int ___ret = __register_ftrace_function(ops); \
5205 if (!___ret) \
5206 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5207 ___ret; \
5208 })
5209# define ftrace_shutdown(ops, command) \
5210 ({ \
5211 int ___ret = __unregister_ftrace_function(ops); \
5212 if (!___ret) \
5213 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5214 ___ret; \
5215 })
5216
5217# define ftrace_startup_sysctl() do { } while (0)
5218# define ftrace_shutdown_sysctl() do { } while (0)
5219
5220static inline int
5221ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5222{
5223 return 1;
5224}
5225
5226static void ftrace_update_trampoline(struct ftrace_ops *ops)
5227{
5228}
5229
5230#endif /* CONFIG_DYNAMIC_FTRACE */
5231
5232__init void ftrace_init_global_array_ops(struct trace_array *tr)
5233{
5234 tr->ops = &global_ops;
5235 tr->ops->private = tr;
5236}
5237
5238void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5239{
5240 /* If we filter on pids, update to use the pid function */
5241 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5242 if (WARN_ON(tr->ops->func != ftrace_stub))
5243 printk("ftrace ops had %pS for function\n",
5244 tr->ops->func);
5245 }
5246 tr->ops->func = func;
5247 tr->ops->private = tr;
5248}
5249
5250void ftrace_reset_array_ops(struct trace_array *tr)
5251{
5252 tr->ops->func = ftrace_stub;
5253}
5254
5255static inline void
5256__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5257 struct ftrace_ops *ignored, struct pt_regs *regs)
5258{
5259 struct ftrace_ops *op;
5260 int bit;
5261
5262 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5263 if (bit < 0)
5264 return;
5265
5266 /*
5267 * Some of the ops may be dynamically allocated,
5268 * they must be freed after a synchronize_sched().
5269 */
5270 preempt_disable_notrace();
5271
5272 do_for_each_ftrace_op(op, ftrace_ops_list) {
5273 /*
5274 * Check the following for each ops before calling their func:
5275 * if RCU flag is set, then rcu_is_watching() must be true
5276 * if PER_CPU is set, then ftrace_function_local_disable()
5277 * must be false
5278 * Otherwise test if the ip matches the ops filter
5279 *
5280 * If any of the above fails then the op->func() is not executed.
5281 */
5282 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5283 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5284 !ftrace_function_local_disabled(op)) &&
5285 ftrace_ops_test(op, ip, regs)) {
5286
5287 if (FTRACE_WARN_ON(!op->func)) {
5288 pr_warn("op=%p %pS\n", op, op);
5289 goto out;
5290 }
5291 op->func(ip, parent_ip, op, regs);
5292 }
5293 } while_for_each_ftrace_op(op);
5294out:
5295 preempt_enable_notrace();
5296 trace_clear_recursion(bit);
5297}
5298
5299/*
5300 * Some archs only support passing ip and parent_ip. Even though
5301 * the list function ignores the op parameter, we do not want any
5302 * C side effects, where a function is called without the caller
5303 * sending a third parameter.
5304 * Archs are to support both the regs and ftrace_ops at the same time.
5305 * If they support ftrace_ops, it is assumed they support regs.
5306 * If call backs want to use regs, they must either check for regs
5307 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5308 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5309 * An architecture can pass partial regs with ftrace_ops and still
5310 * set the ARCH_SUPPORTS_FTRACE_OPS.
5311 */
5312#if ARCH_SUPPORTS_FTRACE_OPS
5313static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5314 struct ftrace_ops *op, struct pt_regs *regs)
5315{
5316 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5317}
5318#else
5319static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5320{
5321 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5322}
5323#endif
5324
5325/*
5326 * If there's only one function registered but it does not support
5327 * recursion, needs RCU protection and/or requires per cpu handling, then
5328 * this function will be called by the mcount trampoline.
5329 */
5330static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
5331 struct ftrace_ops *op, struct pt_regs *regs)
5332{
5333 int bit;
5334
5335 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
5336 return;
5337
5338 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5339 if (bit < 0)
5340 return;
5341
5342 preempt_disable_notrace();
5343
5344 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5345 !ftrace_function_local_disabled(op)) {
5346 op->func(ip, parent_ip, op, regs);
5347 }
5348
5349 preempt_enable_notrace();
5350 trace_clear_recursion(bit);
5351}
5352
5353/**
5354 * ftrace_ops_get_func - get the function a trampoline should call
5355 * @ops: the ops to get the function for
5356 *
5357 * Normally the mcount trampoline will call the ops->func, but there
5358 * are times that it should not. For example, if the ops does not
5359 * have its own recursion protection, then it should call the
5360 * ftrace_ops_recurs_func() instead.
5361 *
5362 * Returns the function that the trampoline should call for @ops.
5363 */
5364ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5365{
5366 /*
5367 * If the function does not handle recursion, needs to be RCU safe,
5368 * or does per cpu logic, then we need to call the assist handler.
5369 */
5370 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
5371 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
5372 return ftrace_ops_assist_func;
5373
5374 return ops->func;
5375}
5376
5377static void
5378ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
5379 struct task_struct *prev, struct task_struct *next)
5380{
5381 struct trace_array *tr = data;
5382 struct trace_pid_list *pid_list;
5383
5384 pid_list = rcu_dereference_sched(tr->function_pids);
5385
5386 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
5387 trace_ignore_this_task(pid_list, next));
5388}
5389
5390static void clear_ftrace_pids(struct trace_array *tr)
5391{
5392 struct trace_pid_list *pid_list;
5393 int cpu;
5394
5395 pid_list = rcu_dereference_protected(tr->function_pids,
5396 lockdep_is_held(&ftrace_lock));
5397 if (!pid_list)
5398 return;
5399
5400 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
5401
5402 for_each_possible_cpu(cpu)
5403 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
5404
5405 rcu_assign_pointer(tr->function_pids, NULL);
5406
5407 /* Wait till all users are no longer using pid filtering */
5408 synchronize_sched();
5409
5410 trace_free_pid_list(pid_list);
5411}
5412
5413static void ftrace_pid_reset(struct trace_array *tr)
5414{
5415 mutex_lock(&ftrace_lock);
5416 clear_ftrace_pids(tr);
5417
5418 ftrace_update_pid_func();
5419 ftrace_startup_all(0);
5420
5421 mutex_unlock(&ftrace_lock);
5422}
5423
5424/* Greater than any max PID */
5425#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
5426
5427static void *fpid_start(struct seq_file *m, loff_t *pos)
5428 __acquires(RCU)
5429{
5430 struct trace_pid_list *pid_list;
5431 struct trace_array *tr = m->private;
5432
5433 mutex_lock(&ftrace_lock);
5434 rcu_read_lock_sched();
5435
5436 pid_list = rcu_dereference_sched(tr->function_pids);
5437
5438 if (!pid_list)
5439 return !(*pos) ? FTRACE_NO_PIDS : NULL;
5440
5441 return trace_pid_start(pid_list, pos);
5442}
5443
5444static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5445{
5446 struct trace_array *tr = m->private;
5447 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
5448
5449 if (v == FTRACE_NO_PIDS)
5450 return NULL;
5451
5452 return trace_pid_next(pid_list, v, pos);
5453}
5454
5455static void fpid_stop(struct seq_file *m, void *p)
5456 __releases(RCU)
5457{
5458 rcu_read_unlock_sched();
5459 mutex_unlock(&ftrace_lock);
5460}
5461
5462static int fpid_show(struct seq_file *m, void *v)
5463{
5464 if (v == FTRACE_NO_PIDS) {
5465 seq_puts(m, "no pid\n");
5466 return 0;
5467 }
5468
5469 return trace_pid_show(m, v);
5470}
5471
5472static const struct seq_operations ftrace_pid_sops = {
5473 .start = fpid_start,
5474 .next = fpid_next,
5475 .stop = fpid_stop,
5476 .show = fpid_show,
5477};
5478
5479static int
5480ftrace_pid_open(struct inode *inode, struct file *file)
5481{
5482 struct trace_array *tr = inode->i_private;
5483 struct seq_file *m;
5484 int ret = 0;
5485
5486 if (trace_array_get(tr) < 0)
5487 return -ENODEV;
5488
5489 if ((file->f_mode & FMODE_WRITE) &&
5490 (file->f_flags & O_TRUNC))
5491 ftrace_pid_reset(tr);
5492
5493 ret = seq_open(file, &ftrace_pid_sops);
5494 if (ret < 0) {
5495 trace_array_put(tr);
5496 } else {
5497 m = file->private_data;
5498 /* copy tr over to seq ops */
5499 m->private = tr;
5500 }
5501
5502 return ret;
5503}
5504
5505static void ignore_task_cpu(void *data)
5506{
5507 struct trace_array *tr = data;
5508 struct trace_pid_list *pid_list;
5509
5510 /*
5511 * This function is called by on_each_cpu() while the
5512 * event_mutex is held.
5513 */
5514 pid_list = rcu_dereference_protected(tr->function_pids,
5515 mutex_is_locked(&ftrace_lock));
5516
5517 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
5518 trace_ignore_this_task(pid_list, current));
5519}
5520
5521static ssize_t
5522ftrace_pid_write(struct file *filp, const char __user *ubuf,
5523 size_t cnt, loff_t *ppos)
5524{
5525 struct seq_file *m = filp->private_data;
5526 struct trace_array *tr = m->private;
5527 struct trace_pid_list *filtered_pids = NULL;
5528 struct trace_pid_list *pid_list;
5529 ssize_t ret;
5530
5531 if (!cnt)
5532 return 0;
5533
5534 mutex_lock(&ftrace_lock);
5535
5536 filtered_pids = rcu_dereference_protected(tr->function_pids,
5537 lockdep_is_held(&ftrace_lock));
5538
5539 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
5540 if (ret < 0)
5541 goto out;
5542
5543 rcu_assign_pointer(tr->function_pids, pid_list);
5544
5545 if (filtered_pids) {
5546 synchronize_sched();
5547 trace_free_pid_list(filtered_pids);
5548 } else if (pid_list) {
5549 /* Register a probe to set whether to ignore the tracing of a task */
5550 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
5551 }
5552
5553 /*
5554 * Ignoring of pids is done at task switch. But we have to
5555 * check for those tasks that are currently running.
5556 * Always do this in case a pid was appended or removed.
5557 */
5558 on_each_cpu(ignore_task_cpu, tr, 1);
5559
5560 ftrace_update_pid_func();
5561 ftrace_startup_all(0);
5562 out:
5563 mutex_unlock(&ftrace_lock);
5564
5565 if (ret > 0)
5566 *ppos += ret;
5567
5568 return ret;
5569}
5570
5571static int
5572ftrace_pid_release(struct inode *inode, struct file *file)
5573{
5574 struct trace_array *tr = inode->i_private;
5575
5576 trace_array_put(tr);
5577
5578 return seq_release(inode, file);
5579}
5580
5581static const struct file_operations ftrace_pid_fops = {
5582 .open = ftrace_pid_open,
5583 .write = ftrace_pid_write,
5584 .read = seq_read,
5585 .llseek = tracing_lseek,
5586 .release = ftrace_pid_release,
5587};
5588
5589void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
5590{
5591 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5592 tr, &ftrace_pid_fops);
5593}
5594
5595void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
5596 struct dentry *d_tracer)
5597{
5598 /* Only the top level directory has the dyn_tracefs and profile */
5599 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
5600
5601 ftrace_init_dyn_tracefs(d_tracer);
5602 ftrace_profile_tracefs(d_tracer);
5603}
5604
5605/**
5606 * ftrace_kill - kill ftrace
5607 *
5608 * This function should be used by panic code. It stops ftrace
5609 * but in a not so nice way. If you need to simply kill ftrace
5610 * from a non-atomic section, use ftrace_kill.
5611 */
5612void ftrace_kill(void)
5613{
5614 ftrace_disabled = 1;
5615 ftrace_enabled = 0;
5616 clear_ftrace_function();
5617}
5618
5619/**
5620 * Test if ftrace is dead or not.
5621 */
5622int ftrace_is_dead(void)
5623{
5624 return ftrace_disabled;
5625}
5626
5627/**
5628 * register_ftrace_function - register a function for profiling
5629 * @ops - ops structure that holds the function for profiling.
5630 *
5631 * Register a function to be called by all functions in the
5632 * kernel.
5633 *
5634 * Note: @ops->func and all the functions it calls must be labeled
5635 * with "notrace", otherwise it will go into a
5636 * recursive loop.
5637 */
5638int register_ftrace_function(struct ftrace_ops *ops)
5639{
5640 int ret = -1;
5641
5642 ftrace_ops_init(ops);
5643
5644 mutex_lock(&ftrace_lock);
5645
5646 ret = ftrace_startup(ops, 0);
5647
5648 mutex_unlock(&ftrace_lock);
5649
5650 return ret;
5651}
5652EXPORT_SYMBOL_GPL(register_ftrace_function);
5653
5654/**
5655 * unregister_ftrace_function - unregister a function for profiling.
5656 * @ops - ops structure that holds the function to unregister
5657 *
5658 * Unregister a function that was added to be called by ftrace profiling.
5659 */
5660int unregister_ftrace_function(struct ftrace_ops *ops)
5661{
5662 int ret;
5663
5664 mutex_lock(&ftrace_lock);
5665 ret = ftrace_shutdown(ops, 0);
5666 mutex_unlock(&ftrace_lock);
5667
5668 return ret;
5669}
5670EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5671
5672int
5673ftrace_enable_sysctl(struct ctl_table *table, int write,
5674 void __user *buffer, size_t *lenp,
5675 loff_t *ppos)
5676{
5677 int ret = -ENODEV;
5678
5679 mutex_lock(&ftrace_lock);
5680
5681 if (unlikely(ftrace_disabled))
5682 goto out;
5683
5684 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5685
5686 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5687 goto out;
5688
5689 last_ftrace_enabled = !!ftrace_enabled;
5690
5691 if (ftrace_enabled) {
5692
5693 /* we are starting ftrace again */
5694 if (ftrace_ops_list != &ftrace_list_end)
5695 update_ftrace_function();
5696
5697 ftrace_startup_sysctl();
5698
5699 } else {
5700 /* stopping ftrace calls (just send to ftrace_stub) */
5701 ftrace_trace_function = ftrace_stub;
5702
5703 ftrace_shutdown_sysctl();
5704 }
5705
5706 out:
5707 mutex_unlock(&ftrace_lock);
5708 return ret;
5709}
5710
5711#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5712
5713static struct ftrace_ops graph_ops = {
5714 .func = ftrace_stub,
5715 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5716 FTRACE_OPS_FL_INITIALIZED |
5717 FTRACE_OPS_FL_PID |
5718 FTRACE_OPS_FL_STUB,
5719#ifdef FTRACE_GRAPH_TRAMP_ADDR
5720 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5721 /* trampoline_size is only needed for dynamically allocated tramps */
5722#endif
5723 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5724};
5725
5726void ftrace_graph_sleep_time_control(bool enable)
5727{
5728 fgraph_sleep_time = enable;
5729}
5730
5731void ftrace_graph_graph_time_control(bool enable)
5732{
5733 fgraph_graph_time = enable;
5734}
5735
5736int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5737{
5738 return 0;
5739}
5740
5741/* The callbacks that hook a function */
5742trace_func_graph_ret_t ftrace_graph_return =
5743 (trace_func_graph_ret_t)ftrace_stub;
5744trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5745static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5746
5747/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5748static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5749{
5750 int i;
5751 int ret = 0;
5752 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5753 struct task_struct *g, *t;
5754
5755 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5756 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5757 * sizeof(struct ftrace_ret_stack),
5758 GFP_KERNEL);
5759 if (!ret_stack_list[i]) {
5760 start = 0;
5761 end = i;
5762 ret = -ENOMEM;
5763 goto free;
5764 }
5765 }
5766
5767 read_lock(&tasklist_lock);
5768 do_each_thread(g, t) {
5769 if (start == end) {
5770 ret = -EAGAIN;
5771 goto unlock;
5772 }
5773
5774 if (t->ret_stack == NULL) {
5775 atomic_set(&t->tracing_graph_pause, 0);
5776 atomic_set(&t->trace_overrun, 0);
5777 t->curr_ret_stack = -1;
5778 /* Make sure the tasks see the -1 first: */
5779 smp_wmb();
5780 t->ret_stack = ret_stack_list[start++];
5781 }
5782 } while_each_thread(g, t);
5783
5784unlock:
5785 read_unlock(&tasklist_lock);
5786free:
5787 for (i = start; i < end; i++)
5788 kfree(ret_stack_list[i]);
5789 return ret;
5790}
5791
5792static void
5793ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5794 struct task_struct *prev, struct task_struct *next)
5795{
5796 unsigned long long timestamp;
5797 int index;
5798
5799 /*
5800 * Does the user want to count the time a function was asleep.
5801 * If so, do not update the time stamps.
5802 */
5803 if (fgraph_sleep_time)
5804 return;
5805
5806 timestamp = trace_clock_local();
5807
5808 prev->ftrace_timestamp = timestamp;
5809
5810 /* only process tasks that we timestamped */
5811 if (!next->ftrace_timestamp)
5812 return;
5813
5814 /*
5815 * Update all the counters in next to make up for the
5816 * time next was sleeping.
5817 */
5818 timestamp -= next->ftrace_timestamp;
5819
5820 for (index = next->curr_ret_stack; index >= 0; index--)
5821 next->ret_stack[index].calltime += timestamp;
5822}
5823
5824/* Allocate a return stack for each task */
5825static int start_graph_tracing(void)
5826{
5827 struct ftrace_ret_stack **ret_stack_list;
5828 int ret, cpu;
5829
5830 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5831 sizeof(struct ftrace_ret_stack *),
5832 GFP_KERNEL);
5833
5834 if (!ret_stack_list)
5835 return -ENOMEM;
5836
5837 /* The cpu_boot init_task->ret_stack will never be freed */
5838 for_each_online_cpu(cpu) {
5839 if (!idle_task(cpu)->ret_stack)
5840 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5841 }
5842
5843 do {
5844 ret = alloc_retstack_tasklist(ret_stack_list);
5845 } while (ret == -EAGAIN);
5846
5847 if (!ret) {
5848 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5849 if (ret)
5850 pr_info("ftrace_graph: Couldn't activate tracepoint"
5851 " probe to kernel_sched_switch\n");
5852 }
5853
5854 kfree(ret_stack_list);
5855 return ret;
5856}
5857
5858/*
5859 * Hibernation protection.
5860 * The state of the current task is too much unstable during
5861 * suspend/restore to disk. We want to protect against that.
5862 */
5863static int
5864ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5865 void *unused)
5866{
5867 switch (state) {
5868 case PM_HIBERNATION_PREPARE:
5869 pause_graph_tracing();
5870 break;
5871
5872 case PM_POST_HIBERNATION:
5873 unpause_graph_tracing();
5874 break;
5875 }
5876 return NOTIFY_DONE;
5877}
5878
5879static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5880{
5881 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5882 return 0;
5883 return __ftrace_graph_entry(trace);
5884}
5885
5886/*
5887 * The function graph tracer should only trace the functions defined
5888 * by set_ftrace_filter and set_ftrace_notrace. If another function
5889 * tracer ops is registered, the graph tracer requires testing the
5890 * function against the global ops, and not just trace any function
5891 * that any ftrace_ops registered.
5892 */
5893static void update_function_graph_func(void)
5894{
5895 struct ftrace_ops *op;
5896 bool do_test = false;
5897
5898 /*
5899 * The graph and global ops share the same set of functions
5900 * to test. If any other ops is on the list, then
5901 * the graph tracing needs to test if its the function
5902 * it should call.
5903 */
5904 do_for_each_ftrace_op(op, ftrace_ops_list) {
5905 if (op != &global_ops && op != &graph_ops &&
5906 op != &ftrace_list_end) {
5907 do_test = true;
5908 /* in double loop, break out with goto */
5909 goto out;
5910 }
5911 } while_for_each_ftrace_op(op);
5912 out:
5913 if (do_test)
5914 ftrace_graph_entry = ftrace_graph_entry_test;
5915 else
5916 ftrace_graph_entry = __ftrace_graph_entry;
5917}
5918
5919static struct notifier_block ftrace_suspend_notifier = {
5920 .notifier_call = ftrace_suspend_notifier_call,
5921};
5922
5923int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5924 trace_func_graph_ent_t entryfunc)
5925{
5926 int ret = 0;
5927
5928 mutex_lock(&ftrace_lock);
5929
5930 /* we currently allow only one tracer registered at a time */
5931 if (ftrace_graph_active) {
5932 ret = -EBUSY;
5933 goto out;
5934 }
5935
5936 register_pm_notifier(&ftrace_suspend_notifier);
5937
5938 ftrace_graph_active++;
5939 ret = start_graph_tracing();
5940 if (ret) {
5941 ftrace_graph_active--;
5942 goto out;
5943 }
5944
5945 ftrace_graph_return = retfunc;
5946
5947 /*
5948 * Update the indirect function to the entryfunc, and the
5949 * function that gets called to the entry_test first. Then
5950 * call the update fgraph entry function to determine if
5951 * the entryfunc should be called directly or not.
5952 */
5953 __ftrace_graph_entry = entryfunc;
5954 ftrace_graph_entry = ftrace_graph_entry_test;
5955 update_function_graph_func();
5956
5957 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5958out:
5959 mutex_unlock(&ftrace_lock);
5960 return ret;
5961}
5962
5963void unregister_ftrace_graph(void)
5964{
5965 mutex_lock(&ftrace_lock);
5966
5967 if (unlikely(!ftrace_graph_active))
5968 goto out;
5969
5970 ftrace_graph_active--;
5971 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5972 ftrace_graph_entry = ftrace_graph_entry_stub;
5973 __ftrace_graph_entry = ftrace_graph_entry_stub;
5974 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5975 unregister_pm_notifier(&ftrace_suspend_notifier);
5976 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5977
5978#ifdef CONFIG_DYNAMIC_FTRACE
5979 /*
5980 * Function graph does not allocate the trampoline, but
5981 * other global_ops do. We need to reset the ALLOC_TRAMP flag
5982 * if one was used.
5983 */
5984 global_ops.trampoline = save_global_trampoline;
5985 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
5986 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
5987#endif
5988
5989 out:
5990 mutex_unlock(&ftrace_lock);
5991}
5992
5993static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5994
5995static void
5996graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5997{
5998 atomic_set(&t->tracing_graph_pause, 0);
5999 atomic_set(&t->trace_overrun, 0);
6000 t->ftrace_timestamp = 0;
6001 /* make curr_ret_stack visible before we add the ret_stack */
6002 smp_wmb();
6003 t->ret_stack = ret_stack;
6004}
6005
6006/*
6007 * Allocate a return stack for the idle task. May be the first
6008 * time through, or it may be done by CPU hotplug online.
6009 */
6010void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
6011{
6012 t->curr_ret_stack = -1;
6013 /*
6014 * The idle task has no parent, it either has its own
6015 * stack or no stack at all.
6016 */
6017 if (t->ret_stack)
6018 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
6019
6020 if (ftrace_graph_active) {
6021 struct ftrace_ret_stack *ret_stack;
6022
6023 ret_stack = per_cpu(idle_ret_stack, cpu);
6024 if (!ret_stack) {
6025 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6026 * sizeof(struct ftrace_ret_stack),
6027 GFP_KERNEL);
6028 if (!ret_stack)
6029 return;
6030 per_cpu(idle_ret_stack, cpu) = ret_stack;
6031 }
6032 graph_init_task(t, ret_stack);
6033 }
6034}
6035
6036/* Allocate a return stack for newly created task */
6037void ftrace_graph_init_task(struct task_struct *t)
6038{
6039 /* Make sure we do not use the parent ret_stack */
6040 t->ret_stack = NULL;
6041 t->curr_ret_stack = -1;
6042
6043 if (ftrace_graph_active) {
6044 struct ftrace_ret_stack *ret_stack;
6045
6046 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6047 * sizeof(struct ftrace_ret_stack),
6048 GFP_KERNEL);
6049 if (!ret_stack)
6050 return;
6051 graph_init_task(t, ret_stack);
6052 }
6053}
6054
6055void ftrace_graph_exit_task(struct task_struct *t)
6056{
6057 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6058
6059 t->ret_stack = NULL;
6060 /* NULL must become visible to IRQs before we free it: */
6061 barrier();
6062
6063 kfree(ret_stack);
6064}
6065#endif