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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 Nadia Yvette Chambers
14 */
15
16#include <linux/stop_machine.h>
17#include <linux/clocksource.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/suspend.h>
21#include <linux/tracefs.h>
22#include <linux/hardirq.h>
23#include <linux/kthread.h>
24#include <linux/uaccess.h>
25#include <linux/bsearch.h>
26#include <linux/module.h>
27#include <linux/ftrace.h>
28#include <linux/sysctl.h>
29#include <linux/slab.h>
30#include <linux/ctype.h>
31#include <linux/sort.h>
32#include <linux/list.h>
33#include <linux/hash.h>
34#include <linux/rcupdate.h>
35
36#include <trace/events/sched.h>
37
38#include <asm/setup.h>
39
40#include "trace_output.h"
41#include "trace_stat.h"
42
43#define FTRACE_WARN_ON(cond) \
44 ({ \
45 int ___r = cond; \
46 if (WARN_ON(___r)) \
47 ftrace_kill(); \
48 ___r; \
49 })
50
51#define FTRACE_WARN_ON_ONCE(cond) \
52 ({ \
53 int ___r = cond; \
54 if (WARN_ON_ONCE(___r)) \
55 ftrace_kill(); \
56 ___r; \
57 })
58
59/* hash bits for specific function selection */
60#define FTRACE_HASH_BITS 7
61#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62#define FTRACE_HASH_DEFAULT_BITS 10
63#define FTRACE_HASH_MAX_BITS 12
64
65#ifdef CONFIG_DYNAMIC_FTRACE
66#define INIT_OPS_HASH(opsname) \
67 .func_hash = &opsname.local_hash, \
68 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
69#define ASSIGN_OPS_HASH(opsname, val) \
70 .func_hash = val, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
72#else
73#define INIT_OPS_HASH(opsname)
74#define ASSIGN_OPS_HASH(opsname, val)
75#endif
76
77static struct ftrace_ops ftrace_list_end __read_mostly = {
78 .func = ftrace_stub,
79 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
80 INIT_OPS_HASH(ftrace_list_end)
81};
82
83/* ftrace_enabled is a method to turn ftrace on or off */
84int ftrace_enabled __read_mostly;
85static int last_ftrace_enabled;
86
87/* Current function tracing op */
88struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
89/* What to set function_trace_op to */
90static struct ftrace_ops *set_function_trace_op;
91
92/* List for set_ftrace_pid's pids. */
93LIST_HEAD(ftrace_pids);
94struct ftrace_pid {
95 struct list_head list;
96 struct pid *pid;
97};
98
99static bool ftrace_pids_enabled(void)
100{
101 return !list_empty(&ftrace_pids);
102}
103
104static void ftrace_update_trampoline(struct ftrace_ops *ops);
105
106/*
107 * ftrace_disabled is set when an anomaly is discovered.
108 * ftrace_disabled is much stronger than ftrace_enabled.
109 */
110static int ftrace_disabled __read_mostly;
111
112static DEFINE_MUTEX(ftrace_lock);
113
114static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
115ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
116static struct ftrace_ops global_ops;
117
118#if ARCH_SUPPORTS_FTRACE_OPS
119static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
120 struct ftrace_ops *op, struct pt_regs *regs);
121#else
122/* See comment below, where ftrace_ops_list_func is defined */
123static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
124#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
125#endif
126
127/*
128 * Traverse the ftrace_global_list, invoking all entries. The reason that we
129 * can use rcu_dereference_raw_notrace() is that elements removed from this list
130 * are simply leaked, so there is no need to interact with a grace-period
131 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
132 * concurrent insertions into the ftrace_global_list.
133 *
134 * Silly Alpha and silly pointer-speculation compiler optimizations!
135 */
136#define do_for_each_ftrace_op(op, list) \
137 op = rcu_dereference_raw_notrace(list); \
138 do
139
140/*
141 * Optimized for just a single item in the list (as that is the normal case).
142 */
143#define while_for_each_ftrace_op(op) \
144 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
145 unlikely((op) != &ftrace_list_end))
146
147static inline void ftrace_ops_init(struct ftrace_ops *ops)
148{
149#ifdef CONFIG_DYNAMIC_FTRACE
150 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
151 mutex_init(&ops->local_hash.regex_lock);
152 ops->func_hash = &ops->local_hash;
153 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
154 }
155#endif
156}
157
158/**
159 * ftrace_nr_registered_ops - return number of ops registered
160 *
161 * Returns the number of ftrace_ops registered and tracing functions
162 */
163int ftrace_nr_registered_ops(void)
164{
165 struct ftrace_ops *ops;
166 int cnt = 0;
167
168 mutex_lock(&ftrace_lock);
169
170 for (ops = ftrace_ops_list;
171 ops != &ftrace_list_end; ops = ops->next)
172 cnt++;
173
174 mutex_unlock(&ftrace_lock);
175
176 return cnt;
177}
178
179static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
180 struct ftrace_ops *op, struct pt_regs *regs)
181{
182 if (!test_tsk_trace_trace(current))
183 return;
184
185 op->saved_func(ip, parent_ip, op, regs);
186}
187
188/**
189 * clear_ftrace_function - reset the ftrace function
190 *
191 * This NULLs the ftrace function and in essence stops
192 * tracing. There may be lag
193 */
194void clear_ftrace_function(void)
195{
196 ftrace_trace_function = ftrace_stub;
197}
198
199static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
200{
201 int cpu;
202
203 for_each_possible_cpu(cpu)
204 *per_cpu_ptr(ops->disabled, cpu) = 1;
205}
206
207static int per_cpu_ops_alloc(struct ftrace_ops *ops)
208{
209 int __percpu *disabled;
210
211 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
212 return -EINVAL;
213
214 disabled = alloc_percpu(int);
215 if (!disabled)
216 return -ENOMEM;
217
218 ops->disabled = disabled;
219 per_cpu_ops_disable_all(ops);
220 return 0;
221}
222
223static void ftrace_sync(struct work_struct *work)
224{
225 /*
226 * This function is just a stub to implement a hard force
227 * of synchronize_sched(). This requires synchronizing
228 * tasks even in userspace and idle.
229 *
230 * Yes, function tracing is rude.
231 */
232}
233
234static void ftrace_sync_ipi(void *data)
235{
236 /* Probably not needed, but do it anyway */
237 smp_rmb();
238}
239
240#ifdef CONFIG_FUNCTION_GRAPH_TRACER
241static void update_function_graph_func(void);
242
243/* Both enabled by default (can be cleared by function_graph tracer flags */
244static bool fgraph_sleep_time = true;
245static bool fgraph_graph_time = true;
246
247#else
248static inline void update_function_graph_func(void) { }
249#endif
250
251
252static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
253{
254 /*
255 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
256 * then it needs to call the list anyway.
257 */
258 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
259 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
260 return ftrace_ops_list_func;
261
262 return ftrace_ops_get_func(ops);
263}
264
265static void update_ftrace_function(void)
266{
267 ftrace_func_t func;
268
269 /*
270 * Prepare the ftrace_ops that the arch callback will use.
271 * If there's only one ftrace_ops registered, the ftrace_ops_list
272 * will point to the ops we want.
273 */
274 set_function_trace_op = ftrace_ops_list;
275
276 /* If there's no ftrace_ops registered, just call the stub function */
277 if (ftrace_ops_list == &ftrace_list_end) {
278 func = ftrace_stub;
279
280 /*
281 * If we are at the end of the list and this ops is
282 * recursion safe and not dynamic and the arch supports passing ops,
283 * then have the mcount trampoline call the function directly.
284 */
285 } else if (ftrace_ops_list->next == &ftrace_list_end) {
286 func = ftrace_ops_get_list_func(ftrace_ops_list);
287
288 } else {
289 /* Just use the default ftrace_ops */
290 set_function_trace_op = &ftrace_list_end;
291 func = ftrace_ops_list_func;
292 }
293
294 update_function_graph_func();
295
296 /* If there's no change, then do nothing more here */
297 if (ftrace_trace_function == func)
298 return;
299
300 /*
301 * If we are using the list function, it doesn't care
302 * about the function_trace_ops.
303 */
304 if (func == ftrace_ops_list_func) {
305 ftrace_trace_function = func;
306 /*
307 * Don't even bother setting function_trace_ops,
308 * it would be racy to do so anyway.
309 */
310 return;
311 }
312
313#ifndef CONFIG_DYNAMIC_FTRACE
314 /*
315 * For static tracing, we need to be a bit more careful.
316 * The function change takes affect immediately. Thus,
317 * we need to coorditate the setting of the function_trace_ops
318 * with the setting of the ftrace_trace_function.
319 *
320 * Set the function to the list ops, which will call the
321 * function we want, albeit indirectly, but it handles the
322 * ftrace_ops and doesn't depend on function_trace_op.
323 */
324 ftrace_trace_function = ftrace_ops_list_func;
325 /*
326 * Make sure all CPUs see this. Yes this is slow, but static
327 * tracing is slow and nasty to have enabled.
328 */
329 schedule_on_each_cpu(ftrace_sync);
330 /* Now all cpus are using the list ops. */
331 function_trace_op = set_function_trace_op;
332 /* Make sure the function_trace_op is visible on all CPUs */
333 smp_wmb();
334 /* Nasty way to force a rmb on all cpus */
335 smp_call_function(ftrace_sync_ipi, NULL, 1);
336 /* OK, we are all set to update the ftrace_trace_function now! */
337#endif /* !CONFIG_DYNAMIC_FTRACE */
338
339 ftrace_trace_function = func;
340}
341
342int using_ftrace_ops_list_func(void)
343{
344 return ftrace_trace_function == ftrace_ops_list_func;
345}
346
347static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
348{
349 ops->next = *list;
350 /*
351 * We are entering ops into the list but another
352 * CPU might be walking that list. We need to make sure
353 * the ops->next pointer is valid before another CPU sees
354 * the ops pointer included into the list.
355 */
356 rcu_assign_pointer(*list, ops);
357}
358
359static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
360{
361 struct ftrace_ops **p;
362
363 /*
364 * If we are removing the last function, then simply point
365 * to the ftrace_stub.
366 */
367 if (*list == ops && ops->next == &ftrace_list_end) {
368 *list = &ftrace_list_end;
369 return 0;
370 }
371
372 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
373 if (*p == ops)
374 break;
375
376 if (*p != ops)
377 return -1;
378
379 *p = (*p)->next;
380 return 0;
381}
382
383static void ftrace_update_trampoline(struct ftrace_ops *ops);
384
385static int __register_ftrace_function(struct ftrace_ops *ops)
386{
387 if (ops->flags & FTRACE_OPS_FL_DELETED)
388 return -EINVAL;
389
390 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
391 return -EBUSY;
392
393#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
394 /*
395 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
396 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
397 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
398 */
399 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
400 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
401 return -EINVAL;
402
403 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
404 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
405#endif
406
407 if (!core_kernel_data((unsigned long)ops))
408 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
409
410 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
411 if (per_cpu_ops_alloc(ops))
412 return -ENOMEM;
413 }
414
415 add_ftrace_ops(&ftrace_ops_list, ops);
416
417 /* Always save the function, and reset at unregistering */
418 ops->saved_func = ops->func;
419
420 if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
421 ops->func = ftrace_pid_func;
422
423 ftrace_update_trampoline(ops);
424
425 if (ftrace_enabled)
426 update_ftrace_function();
427
428 return 0;
429}
430
431static int __unregister_ftrace_function(struct ftrace_ops *ops)
432{
433 int ret;
434
435 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
436 return -EBUSY;
437
438 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
439
440 if (ret < 0)
441 return ret;
442
443 if (ftrace_enabled)
444 update_ftrace_function();
445
446 ops->func = ops->saved_func;
447
448 return 0;
449}
450
451static void ftrace_update_pid_func(void)
452{
453 bool enabled = ftrace_pids_enabled();
454 struct ftrace_ops *op;
455
456 /* Only do something if we are tracing something */
457 if (ftrace_trace_function == ftrace_stub)
458 return;
459
460 do_for_each_ftrace_op(op, ftrace_ops_list) {
461 if (op->flags & FTRACE_OPS_FL_PID) {
462 op->func = enabled ? ftrace_pid_func :
463 op->saved_func;
464 ftrace_update_trampoline(op);
465 }
466 } while_for_each_ftrace_op(op);
467
468 update_ftrace_function();
469}
470
471#ifdef CONFIG_FUNCTION_PROFILER
472struct ftrace_profile {
473 struct hlist_node node;
474 unsigned long ip;
475 unsigned long counter;
476#ifdef CONFIG_FUNCTION_GRAPH_TRACER
477 unsigned long long time;
478 unsigned long long time_squared;
479#endif
480};
481
482struct ftrace_profile_page {
483 struct ftrace_profile_page *next;
484 unsigned long index;
485 struct ftrace_profile records[];
486};
487
488struct ftrace_profile_stat {
489 atomic_t disabled;
490 struct hlist_head *hash;
491 struct ftrace_profile_page *pages;
492 struct ftrace_profile_page *start;
493 struct tracer_stat stat;
494};
495
496#define PROFILE_RECORDS_SIZE \
497 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
498
499#define PROFILES_PER_PAGE \
500 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
501
502static int ftrace_profile_enabled __read_mostly;
503
504/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
505static DEFINE_MUTEX(ftrace_profile_lock);
506
507static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
508
509#define FTRACE_PROFILE_HASH_BITS 10
510#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
511
512static void *
513function_stat_next(void *v, int idx)
514{
515 struct ftrace_profile *rec = v;
516 struct ftrace_profile_page *pg;
517
518 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
519
520 again:
521 if (idx != 0)
522 rec++;
523
524 if ((void *)rec >= (void *)&pg->records[pg->index]) {
525 pg = pg->next;
526 if (!pg)
527 return NULL;
528 rec = &pg->records[0];
529 if (!rec->counter)
530 goto again;
531 }
532
533 return rec;
534}
535
536static void *function_stat_start(struct tracer_stat *trace)
537{
538 struct ftrace_profile_stat *stat =
539 container_of(trace, struct ftrace_profile_stat, stat);
540
541 if (!stat || !stat->start)
542 return NULL;
543
544 return function_stat_next(&stat->start->records[0], 0);
545}
546
547#ifdef CONFIG_FUNCTION_GRAPH_TRACER
548/* function graph compares on total time */
549static int function_stat_cmp(void *p1, void *p2)
550{
551 struct ftrace_profile *a = p1;
552 struct ftrace_profile *b = p2;
553
554 if (a->time < b->time)
555 return -1;
556 if (a->time > b->time)
557 return 1;
558 else
559 return 0;
560}
561#else
562/* not function graph compares against hits */
563static int function_stat_cmp(void *p1, void *p2)
564{
565 struct ftrace_profile *a = p1;
566 struct ftrace_profile *b = p2;
567
568 if (a->counter < b->counter)
569 return -1;
570 if (a->counter > b->counter)
571 return 1;
572 else
573 return 0;
574}
575#endif
576
577static int function_stat_headers(struct seq_file *m)
578{
579#ifdef CONFIG_FUNCTION_GRAPH_TRACER
580 seq_puts(m, " Function "
581 "Hit Time Avg s^2\n"
582 " -------- "
583 "--- ---- --- ---\n");
584#else
585 seq_puts(m, " Function Hit\n"
586 " -------- ---\n");
587#endif
588 return 0;
589}
590
591static int function_stat_show(struct seq_file *m, void *v)
592{
593 struct ftrace_profile *rec = v;
594 char str[KSYM_SYMBOL_LEN];
595 int ret = 0;
596#ifdef CONFIG_FUNCTION_GRAPH_TRACER
597 static struct trace_seq s;
598 unsigned long long avg;
599 unsigned long long stddev;
600#endif
601 mutex_lock(&ftrace_profile_lock);
602
603 /* we raced with function_profile_reset() */
604 if (unlikely(rec->counter == 0)) {
605 ret = -EBUSY;
606 goto out;
607 }
608
609#ifdef CONFIG_FUNCTION_GRAPH_TRACER
610 avg = rec->time;
611 do_div(avg, rec->counter);
612 if (tracing_thresh && (avg < tracing_thresh))
613 goto out;
614#endif
615
616 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
617 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
618
619#ifdef CONFIG_FUNCTION_GRAPH_TRACER
620 seq_puts(m, " ");
621
622 /* Sample standard deviation (s^2) */
623 if (rec->counter <= 1)
624 stddev = 0;
625 else {
626 /*
627 * Apply Welford's method:
628 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
629 */
630 stddev = rec->counter * rec->time_squared -
631 rec->time * rec->time;
632
633 /*
634 * Divide only 1000 for ns^2 -> us^2 conversion.
635 * trace_print_graph_duration will divide 1000 again.
636 */
637 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
638 }
639
640 trace_seq_init(&s);
641 trace_print_graph_duration(rec->time, &s);
642 trace_seq_puts(&s, " ");
643 trace_print_graph_duration(avg, &s);
644 trace_seq_puts(&s, " ");
645 trace_print_graph_duration(stddev, &s);
646 trace_print_seq(m, &s);
647#endif
648 seq_putc(m, '\n');
649out:
650 mutex_unlock(&ftrace_profile_lock);
651
652 return ret;
653}
654
655static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
656{
657 struct ftrace_profile_page *pg;
658
659 pg = stat->pages = stat->start;
660
661 while (pg) {
662 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
663 pg->index = 0;
664 pg = pg->next;
665 }
666
667 memset(stat->hash, 0,
668 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
669}
670
671int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
672{
673 struct ftrace_profile_page *pg;
674 int functions;
675 int pages;
676 int i;
677
678 /* If we already allocated, do nothing */
679 if (stat->pages)
680 return 0;
681
682 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
683 if (!stat->pages)
684 return -ENOMEM;
685
686#ifdef CONFIG_DYNAMIC_FTRACE
687 functions = ftrace_update_tot_cnt;
688#else
689 /*
690 * We do not know the number of functions that exist because
691 * dynamic tracing is what counts them. With past experience
692 * we have around 20K functions. That should be more than enough.
693 * It is highly unlikely we will execute every function in
694 * the kernel.
695 */
696 functions = 20000;
697#endif
698
699 pg = stat->start = stat->pages;
700
701 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
702
703 for (i = 1; i < pages; i++) {
704 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
705 if (!pg->next)
706 goto out_free;
707 pg = pg->next;
708 }
709
710 return 0;
711
712 out_free:
713 pg = stat->start;
714 while (pg) {
715 unsigned long tmp = (unsigned long)pg;
716
717 pg = pg->next;
718 free_page(tmp);
719 }
720
721 stat->pages = NULL;
722 stat->start = NULL;
723
724 return -ENOMEM;
725}
726
727static int ftrace_profile_init_cpu(int cpu)
728{
729 struct ftrace_profile_stat *stat;
730 int size;
731
732 stat = &per_cpu(ftrace_profile_stats, cpu);
733
734 if (stat->hash) {
735 /* If the profile is already created, simply reset it */
736 ftrace_profile_reset(stat);
737 return 0;
738 }
739
740 /*
741 * We are profiling all functions, but usually only a few thousand
742 * functions are hit. We'll make a hash of 1024 items.
743 */
744 size = FTRACE_PROFILE_HASH_SIZE;
745
746 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
747
748 if (!stat->hash)
749 return -ENOMEM;
750
751 /* Preallocate the function profiling pages */
752 if (ftrace_profile_pages_init(stat) < 0) {
753 kfree(stat->hash);
754 stat->hash = NULL;
755 return -ENOMEM;
756 }
757
758 return 0;
759}
760
761static int ftrace_profile_init(void)
762{
763 int cpu;
764 int ret = 0;
765
766 for_each_possible_cpu(cpu) {
767 ret = ftrace_profile_init_cpu(cpu);
768 if (ret)
769 break;
770 }
771
772 return ret;
773}
774
775/* interrupts must be disabled */
776static struct ftrace_profile *
777ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
778{
779 struct ftrace_profile *rec;
780 struct hlist_head *hhd;
781 unsigned long key;
782
783 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
784 hhd = &stat->hash[key];
785
786 if (hlist_empty(hhd))
787 return NULL;
788
789 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
790 if (rec->ip == ip)
791 return rec;
792 }
793
794 return NULL;
795}
796
797static void ftrace_add_profile(struct ftrace_profile_stat *stat,
798 struct ftrace_profile *rec)
799{
800 unsigned long key;
801
802 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
803 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
804}
805
806/*
807 * The memory is already allocated, this simply finds a new record to use.
808 */
809static struct ftrace_profile *
810ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
811{
812 struct ftrace_profile *rec = NULL;
813
814 /* prevent recursion (from NMIs) */
815 if (atomic_inc_return(&stat->disabled) != 1)
816 goto out;
817
818 /*
819 * Try to find the function again since an NMI
820 * could have added it
821 */
822 rec = ftrace_find_profiled_func(stat, ip);
823 if (rec)
824 goto out;
825
826 if (stat->pages->index == PROFILES_PER_PAGE) {
827 if (!stat->pages->next)
828 goto out;
829 stat->pages = stat->pages->next;
830 }
831
832 rec = &stat->pages->records[stat->pages->index++];
833 rec->ip = ip;
834 ftrace_add_profile(stat, rec);
835
836 out:
837 atomic_dec(&stat->disabled);
838
839 return rec;
840}
841
842static void
843function_profile_call(unsigned long ip, unsigned long parent_ip,
844 struct ftrace_ops *ops, struct pt_regs *regs)
845{
846 struct ftrace_profile_stat *stat;
847 struct ftrace_profile *rec;
848 unsigned long flags;
849
850 if (!ftrace_profile_enabled)
851 return;
852
853 local_irq_save(flags);
854
855 stat = this_cpu_ptr(&ftrace_profile_stats);
856 if (!stat->hash || !ftrace_profile_enabled)
857 goto out;
858
859 rec = ftrace_find_profiled_func(stat, ip);
860 if (!rec) {
861 rec = ftrace_profile_alloc(stat, ip);
862 if (!rec)
863 goto out;
864 }
865
866 rec->counter++;
867 out:
868 local_irq_restore(flags);
869}
870
871#ifdef CONFIG_FUNCTION_GRAPH_TRACER
872static int profile_graph_entry(struct ftrace_graph_ent *trace)
873{
874 function_profile_call(trace->func, 0, NULL, NULL);
875 return 1;
876}
877
878static void profile_graph_return(struct ftrace_graph_ret *trace)
879{
880 struct ftrace_profile_stat *stat;
881 unsigned long long calltime;
882 struct ftrace_profile *rec;
883 unsigned long flags;
884
885 local_irq_save(flags);
886 stat = this_cpu_ptr(&ftrace_profile_stats);
887 if (!stat->hash || !ftrace_profile_enabled)
888 goto out;
889
890 /* If the calltime was zero'd ignore it */
891 if (!trace->calltime)
892 goto out;
893
894 calltime = trace->rettime - trace->calltime;
895
896 if (!fgraph_graph_time) {
897 int index;
898
899 index = trace->depth;
900
901 /* Append this call time to the parent time to subtract */
902 if (index)
903 current->ret_stack[index - 1].subtime += calltime;
904
905 if (current->ret_stack[index].subtime < calltime)
906 calltime -= current->ret_stack[index].subtime;
907 else
908 calltime = 0;
909 }
910
911 rec = ftrace_find_profiled_func(stat, trace->func);
912 if (rec) {
913 rec->time += calltime;
914 rec->time_squared += calltime * calltime;
915 }
916
917 out:
918 local_irq_restore(flags);
919}
920
921static int register_ftrace_profiler(void)
922{
923 return register_ftrace_graph(&profile_graph_return,
924 &profile_graph_entry);
925}
926
927static void unregister_ftrace_profiler(void)
928{
929 unregister_ftrace_graph();
930}
931#else
932static struct ftrace_ops ftrace_profile_ops __read_mostly = {
933 .func = function_profile_call,
934 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
935 INIT_OPS_HASH(ftrace_profile_ops)
936};
937
938static int register_ftrace_profiler(void)
939{
940 return register_ftrace_function(&ftrace_profile_ops);
941}
942
943static void unregister_ftrace_profiler(void)
944{
945 unregister_ftrace_function(&ftrace_profile_ops);
946}
947#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
948
949static ssize_t
950ftrace_profile_write(struct file *filp, const char __user *ubuf,
951 size_t cnt, loff_t *ppos)
952{
953 unsigned long val;
954 int ret;
955
956 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
957 if (ret)
958 return ret;
959
960 val = !!val;
961
962 mutex_lock(&ftrace_profile_lock);
963 if (ftrace_profile_enabled ^ val) {
964 if (val) {
965 ret = ftrace_profile_init();
966 if (ret < 0) {
967 cnt = ret;
968 goto out;
969 }
970
971 ret = register_ftrace_profiler();
972 if (ret < 0) {
973 cnt = ret;
974 goto out;
975 }
976 ftrace_profile_enabled = 1;
977 } else {
978 ftrace_profile_enabled = 0;
979 /*
980 * unregister_ftrace_profiler calls stop_machine
981 * so this acts like an synchronize_sched.
982 */
983 unregister_ftrace_profiler();
984 }
985 }
986 out:
987 mutex_unlock(&ftrace_profile_lock);
988
989 *ppos += cnt;
990
991 return cnt;
992}
993
994static ssize_t
995ftrace_profile_read(struct file *filp, char __user *ubuf,
996 size_t cnt, loff_t *ppos)
997{
998 char buf[64]; /* big enough to hold a number */
999 int r;
1000
1001 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1002 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1003}
1004
1005static const struct file_operations ftrace_profile_fops = {
1006 .open = tracing_open_generic,
1007 .read = ftrace_profile_read,
1008 .write = ftrace_profile_write,
1009 .llseek = default_llseek,
1010};
1011
1012/* used to initialize the real stat files */
1013static struct tracer_stat function_stats __initdata = {
1014 .name = "functions",
1015 .stat_start = function_stat_start,
1016 .stat_next = function_stat_next,
1017 .stat_cmp = function_stat_cmp,
1018 .stat_headers = function_stat_headers,
1019 .stat_show = function_stat_show
1020};
1021
1022static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1023{
1024 struct ftrace_profile_stat *stat;
1025 struct dentry *entry;
1026 char *name;
1027 int ret;
1028 int cpu;
1029
1030 for_each_possible_cpu(cpu) {
1031 stat = &per_cpu(ftrace_profile_stats, cpu);
1032
1033 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1034 if (!name) {
1035 /*
1036 * The files created are permanent, if something happens
1037 * we still do not free memory.
1038 */
1039 WARN(1,
1040 "Could not allocate stat file for cpu %d\n",
1041 cpu);
1042 return;
1043 }
1044 stat->stat = function_stats;
1045 stat->stat.name = name;
1046 ret = register_stat_tracer(&stat->stat);
1047 if (ret) {
1048 WARN(1,
1049 "Could not register function stat for cpu %d\n",
1050 cpu);
1051 kfree(name);
1052 return;
1053 }
1054 }
1055
1056 entry = tracefs_create_file("function_profile_enabled", 0644,
1057 d_tracer, NULL, &ftrace_profile_fops);
1058 if (!entry)
1059 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1060}
1061
1062#else /* CONFIG_FUNCTION_PROFILER */
1063static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1064{
1065}
1066#endif /* CONFIG_FUNCTION_PROFILER */
1067
1068static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1069
1070#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1071static int ftrace_graph_active;
1072#else
1073# define ftrace_graph_active 0
1074#endif
1075
1076#ifdef CONFIG_DYNAMIC_FTRACE
1077
1078static struct ftrace_ops *removed_ops;
1079
1080/*
1081 * Set when doing a global update, like enabling all recs or disabling them.
1082 * It is not set when just updating a single ftrace_ops.
1083 */
1084static bool update_all_ops;
1085
1086#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1087# error Dynamic ftrace depends on MCOUNT_RECORD
1088#endif
1089
1090static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1091
1092struct ftrace_func_probe {
1093 struct hlist_node node;
1094 struct ftrace_probe_ops *ops;
1095 unsigned long flags;
1096 unsigned long ip;
1097 void *data;
1098 struct list_head free_list;
1099};
1100
1101struct ftrace_func_entry {
1102 struct hlist_node hlist;
1103 unsigned long ip;
1104};
1105
1106struct ftrace_hash {
1107 unsigned long size_bits;
1108 struct hlist_head *buckets;
1109 unsigned long count;
1110 struct rcu_head rcu;
1111};
1112
1113/*
1114 * We make these constant because no one should touch them,
1115 * but they are used as the default "empty hash", to avoid allocating
1116 * it all the time. These are in a read only section such that if
1117 * anyone does try to modify it, it will cause an exception.
1118 */
1119static const struct hlist_head empty_buckets[1];
1120static const struct ftrace_hash empty_hash = {
1121 .buckets = (struct hlist_head *)empty_buckets,
1122};
1123#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1124
1125static struct ftrace_ops global_ops = {
1126 .func = ftrace_stub,
1127 .local_hash.notrace_hash = EMPTY_HASH,
1128 .local_hash.filter_hash = EMPTY_HASH,
1129 INIT_OPS_HASH(global_ops)
1130 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1131 FTRACE_OPS_FL_INITIALIZED |
1132 FTRACE_OPS_FL_PID,
1133};
1134
1135/*
1136 * This is used by __kernel_text_address() to return true if the
1137 * address is on a dynamically allocated trampoline that would
1138 * not return true for either core_kernel_text() or
1139 * is_module_text_address().
1140 */
1141bool is_ftrace_trampoline(unsigned long addr)
1142{
1143 struct ftrace_ops *op;
1144 bool ret = false;
1145
1146 /*
1147 * Some of the ops may be dynamically allocated,
1148 * they are freed after a synchronize_sched().
1149 */
1150 preempt_disable_notrace();
1151
1152 do_for_each_ftrace_op(op, ftrace_ops_list) {
1153 /*
1154 * This is to check for dynamically allocated trampolines.
1155 * Trampolines that are in kernel text will have
1156 * core_kernel_text() return true.
1157 */
1158 if (op->trampoline && op->trampoline_size)
1159 if (addr >= op->trampoline &&
1160 addr < op->trampoline + op->trampoline_size) {
1161 ret = true;
1162 goto out;
1163 }
1164 } while_for_each_ftrace_op(op);
1165
1166 out:
1167 preempt_enable_notrace();
1168
1169 return ret;
1170}
1171
1172struct ftrace_page {
1173 struct ftrace_page *next;
1174 struct dyn_ftrace *records;
1175 int index;
1176 int size;
1177};
1178
1179#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1180#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1181
1182/* estimate from running different kernels */
1183#define NR_TO_INIT 10000
1184
1185static struct ftrace_page *ftrace_pages_start;
1186static struct ftrace_page *ftrace_pages;
1187
1188static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1189{
1190 return !hash || !hash->count;
1191}
1192
1193static struct ftrace_func_entry *
1194ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1195{
1196 unsigned long key;
1197 struct ftrace_func_entry *entry;
1198 struct hlist_head *hhd;
1199
1200 if (ftrace_hash_empty(hash))
1201 return NULL;
1202
1203 if (hash->size_bits > 0)
1204 key = hash_long(ip, hash->size_bits);
1205 else
1206 key = 0;
1207
1208 hhd = &hash->buckets[key];
1209
1210 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1211 if (entry->ip == ip)
1212 return entry;
1213 }
1214 return NULL;
1215}
1216
1217static void __add_hash_entry(struct ftrace_hash *hash,
1218 struct ftrace_func_entry *entry)
1219{
1220 struct hlist_head *hhd;
1221 unsigned long key;
1222
1223 if (hash->size_bits)
1224 key = hash_long(entry->ip, hash->size_bits);
1225 else
1226 key = 0;
1227
1228 hhd = &hash->buckets[key];
1229 hlist_add_head(&entry->hlist, hhd);
1230 hash->count++;
1231}
1232
1233static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1234{
1235 struct ftrace_func_entry *entry;
1236
1237 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1238 if (!entry)
1239 return -ENOMEM;
1240
1241 entry->ip = ip;
1242 __add_hash_entry(hash, entry);
1243
1244 return 0;
1245}
1246
1247static void
1248free_hash_entry(struct ftrace_hash *hash,
1249 struct ftrace_func_entry *entry)
1250{
1251 hlist_del(&entry->hlist);
1252 kfree(entry);
1253 hash->count--;
1254}
1255
1256static void
1257remove_hash_entry(struct ftrace_hash *hash,
1258 struct ftrace_func_entry *entry)
1259{
1260 hlist_del(&entry->hlist);
1261 hash->count--;
1262}
1263
1264static void ftrace_hash_clear(struct ftrace_hash *hash)
1265{
1266 struct hlist_head *hhd;
1267 struct hlist_node *tn;
1268 struct ftrace_func_entry *entry;
1269 int size = 1 << hash->size_bits;
1270 int i;
1271
1272 if (!hash->count)
1273 return;
1274
1275 for (i = 0; i < size; i++) {
1276 hhd = &hash->buckets[i];
1277 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1278 free_hash_entry(hash, entry);
1279 }
1280 FTRACE_WARN_ON(hash->count);
1281}
1282
1283static void free_ftrace_hash(struct ftrace_hash *hash)
1284{
1285 if (!hash || hash == EMPTY_HASH)
1286 return;
1287 ftrace_hash_clear(hash);
1288 kfree(hash->buckets);
1289 kfree(hash);
1290}
1291
1292static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1293{
1294 struct ftrace_hash *hash;
1295
1296 hash = container_of(rcu, struct ftrace_hash, rcu);
1297 free_ftrace_hash(hash);
1298}
1299
1300static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1301{
1302 if (!hash || hash == EMPTY_HASH)
1303 return;
1304 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1305}
1306
1307void ftrace_free_filter(struct ftrace_ops *ops)
1308{
1309 ftrace_ops_init(ops);
1310 free_ftrace_hash(ops->func_hash->filter_hash);
1311 free_ftrace_hash(ops->func_hash->notrace_hash);
1312}
1313
1314static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1315{
1316 struct ftrace_hash *hash;
1317 int size;
1318
1319 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1320 if (!hash)
1321 return NULL;
1322
1323 size = 1 << size_bits;
1324 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1325
1326 if (!hash->buckets) {
1327 kfree(hash);
1328 return NULL;
1329 }
1330
1331 hash->size_bits = size_bits;
1332
1333 return hash;
1334}
1335
1336static struct ftrace_hash *
1337alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1338{
1339 struct ftrace_func_entry *entry;
1340 struct ftrace_hash *new_hash;
1341 int size;
1342 int ret;
1343 int i;
1344
1345 new_hash = alloc_ftrace_hash(size_bits);
1346 if (!new_hash)
1347 return NULL;
1348
1349 /* Empty hash? */
1350 if (ftrace_hash_empty(hash))
1351 return new_hash;
1352
1353 size = 1 << hash->size_bits;
1354 for (i = 0; i < size; i++) {
1355 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1356 ret = add_hash_entry(new_hash, entry->ip);
1357 if (ret < 0)
1358 goto free_hash;
1359 }
1360 }
1361
1362 FTRACE_WARN_ON(new_hash->count != hash->count);
1363
1364 return new_hash;
1365
1366 free_hash:
1367 free_ftrace_hash(new_hash);
1368 return NULL;
1369}
1370
1371static void
1372ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1373static void
1374ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1375
1376static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1377 struct ftrace_hash *new_hash);
1378
1379static int
1380ftrace_hash_move(struct ftrace_ops *ops, int enable,
1381 struct ftrace_hash **dst, struct ftrace_hash *src)
1382{
1383 struct ftrace_func_entry *entry;
1384 struct hlist_node *tn;
1385 struct hlist_head *hhd;
1386 struct ftrace_hash *new_hash;
1387 int size = src->count;
1388 int bits = 0;
1389 int ret;
1390 int i;
1391
1392 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1393 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1394 return -EINVAL;
1395
1396 /*
1397 * If the new source is empty, just free dst and assign it
1398 * the empty_hash.
1399 */
1400 if (!src->count) {
1401 new_hash = EMPTY_HASH;
1402 goto update;
1403 }
1404
1405 /*
1406 * Make the hash size about 1/2 the # found
1407 */
1408 for (size /= 2; size; size >>= 1)
1409 bits++;
1410
1411 /* Don't allocate too much */
1412 if (bits > FTRACE_HASH_MAX_BITS)
1413 bits = FTRACE_HASH_MAX_BITS;
1414
1415 new_hash = alloc_ftrace_hash(bits);
1416 if (!new_hash)
1417 return -ENOMEM;
1418
1419 size = 1 << src->size_bits;
1420 for (i = 0; i < size; i++) {
1421 hhd = &src->buckets[i];
1422 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1423 remove_hash_entry(src, entry);
1424 __add_hash_entry(new_hash, entry);
1425 }
1426 }
1427
1428update:
1429 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1430 if (enable) {
1431 /* IPMODIFY should be updated only when filter_hash updating */
1432 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1433 if (ret < 0) {
1434 free_ftrace_hash(new_hash);
1435 return ret;
1436 }
1437 }
1438
1439 /*
1440 * Remove the current set, update the hash and add
1441 * them back.
1442 */
1443 ftrace_hash_rec_disable_modify(ops, enable);
1444
1445 rcu_assign_pointer(*dst, new_hash);
1446
1447 ftrace_hash_rec_enable_modify(ops, enable);
1448
1449 return 0;
1450}
1451
1452static bool hash_contains_ip(unsigned long ip,
1453 struct ftrace_ops_hash *hash)
1454{
1455 /*
1456 * The function record is a match if it exists in the filter
1457 * hash and not in the notrace hash. Note, an emty hash is
1458 * considered a match for the filter hash, but an empty
1459 * notrace hash is considered not in the notrace hash.
1460 */
1461 return (ftrace_hash_empty(hash->filter_hash) ||
1462 ftrace_lookup_ip(hash->filter_hash, ip)) &&
1463 (ftrace_hash_empty(hash->notrace_hash) ||
1464 !ftrace_lookup_ip(hash->notrace_hash, ip));
1465}
1466
1467/*
1468 * Test the hashes for this ops to see if we want to call
1469 * the ops->func or not.
1470 *
1471 * It's a match if the ip is in the ops->filter_hash or
1472 * the filter_hash does not exist or is empty,
1473 * AND
1474 * the ip is not in the ops->notrace_hash.
1475 *
1476 * This needs to be called with preemption disabled as
1477 * the hashes are freed with call_rcu_sched().
1478 */
1479static int
1480ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1481{
1482 struct ftrace_ops_hash hash;
1483 int ret;
1484
1485#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1486 /*
1487 * There's a small race when adding ops that the ftrace handler
1488 * that wants regs, may be called without them. We can not
1489 * allow that handler to be called if regs is NULL.
1490 */
1491 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1492 return 0;
1493#endif
1494
1495 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1496 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1497
1498 if (hash_contains_ip(ip, &hash))
1499 ret = 1;
1500 else
1501 ret = 0;
1502
1503 return ret;
1504}
1505
1506/*
1507 * This is a double for. Do not use 'break' to break out of the loop,
1508 * you must use a goto.
1509 */
1510#define do_for_each_ftrace_rec(pg, rec) \
1511 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1512 int _____i; \
1513 for (_____i = 0; _____i < pg->index; _____i++) { \
1514 rec = &pg->records[_____i];
1515
1516#define while_for_each_ftrace_rec() \
1517 } \
1518 }
1519
1520
1521static int ftrace_cmp_recs(const void *a, const void *b)
1522{
1523 const struct dyn_ftrace *key = a;
1524 const struct dyn_ftrace *rec = b;
1525
1526 if (key->flags < rec->ip)
1527 return -1;
1528 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1529 return 1;
1530 return 0;
1531}
1532
1533static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1534{
1535 struct ftrace_page *pg;
1536 struct dyn_ftrace *rec;
1537 struct dyn_ftrace key;
1538
1539 key.ip = start;
1540 key.flags = end; /* overload flags, as it is unsigned long */
1541
1542 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1543 if (end < pg->records[0].ip ||
1544 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1545 continue;
1546 rec = bsearch(&key, pg->records, pg->index,
1547 sizeof(struct dyn_ftrace),
1548 ftrace_cmp_recs);
1549 if (rec)
1550 return rec->ip;
1551 }
1552
1553 return 0;
1554}
1555
1556/**
1557 * ftrace_location - return true if the ip giving is a traced location
1558 * @ip: the instruction pointer to check
1559 *
1560 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1561 * That is, the instruction that is either a NOP or call to
1562 * the function tracer. It checks the ftrace internal tables to
1563 * determine if the address belongs or not.
1564 */
1565unsigned long ftrace_location(unsigned long ip)
1566{
1567 return ftrace_location_range(ip, ip);
1568}
1569
1570/**
1571 * ftrace_text_reserved - return true if range contains an ftrace location
1572 * @start: start of range to search
1573 * @end: end of range to search (inclusive). @end points to the last byte to check.
1574 *
1575 * Returns 1 if @start and @end contains a ftrace location.
1576 * That is, the instruction that is either a NOP or call to
1577 * the function tracer. It checks the ftrace internal tables to
1578 * determine if the address belongs or not.
1579 */
1580int ftrace_text_reserved(const void *start, const void *end)
1581{
1582 unsigned long ret;
1583
1584 ret = ftrace_location_range((unsigned long)start,
1585 (unsigned long)end);
1586
1587 return (int)!!ret;
1588}
1589
1590/* Test if ops registered to this rec needs regs */
1591static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1592{
1593 struct ftrace_ops *ops;
1594 bool keep_regs = false;
1595
1596 for (ops = ftrace_ops_list;
1597 ops != &ftrace_list_end; ops = ops->next) {
1598 /* pass rec in as regs to have non-NULL val */
1599 if (ftrace_ops_test(ops, rec->ip, rec)) {
1600 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1601 keep_regs = true;
1602 break;
1603 }
1604 }
1605 }
1606
1607 return keep_regs;
1608}
1609
1610static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1611 int filter_hash,
1612 bool inc)
1613{
1614 struct ftrace_hash *hash;
1615 struct ftrace_hash *other_hash;
1616 struct ftrace_page *pg;
1617 struct dyn_ftrace *rec;
1618 bool update = false;
1619 int count = 0;
1620 int all = 0;
1621
1622 /* Only update if the ops has been registered */
1623 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1624 return false;
1625
1626 /*
1627 * In the filter_hash case:
1628 * If the count is zero, we update all records.
1629 * Otherwise we just update the items in the hash.
1630 *
1631 * In the notrace_hash case:
1632 * We enable the update in the hash.
1633 * As disabling notrace means enabling the tracing,
1634 * and enabling notrace means disabling, the inc variable
1635 * gets inversed.
1636 */
1637 if (filter_hash) {
1638 hash = ops->func_hash->filter_hash;
1639 other_hash = ops->func_hash->notrace_hash;
1640 if (ftrace_hash_empty(hash))
1641 all = 1;
1642 } else {
1643 inc = !inc;
1644 hash = ops->func_hash->notrace_hash;
1645 other_hash = ops->func_hash->filter_hash;
1646 /*
1647 * If the notrace hash has no items,
1648 * then there's nothing to do.
1649 */
1650 if (ftrace_hash_empty(hash))
1651 return false;
1652 }
1653
1654 do_for_each_ftrace_rec(pg, rec) {
1655 int in_other_hash = 0;
1656 int in_hash = 0;
1657 int match = 0;
1658
1659 if (rec->flags & FTRACE_FL_DISABLED)
1660 continue;
1661
1662 if (all) {
1663 /*
1664 * Only the filter_hash affects all records.
1665 * Update if the record is not in the notrace hash.
1666 */
1667 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1668 match = 1;
1669 } else {
1670 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1671 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1672
1673 /*
1674 * If filter_hash is set, we want to match all functions
1675 * that are in the hash but not in the other hash.
1676 *
1677 * If filter_hash is not set, then we are decrementing.
1678 * That means we match anything that is in the hash
1679 * and also in the other_hash. That is, we need to turn
1680 * off functions in the other hash because they are disabled
1681 * by this hash.
1682 */
1683 if (filter_hash && in_hash && !in_other_hash)
1684 match = 1;
1685 else if (!filter_hash && in_hash &&
1686 (in_other_hash || ftrace_hash_empty(other_hash)))
1687 match = 1;
1688 }
1689 if (!match)
1690 continue;
1691
1692 if (inc) {
1693 rec->flags++;
1694 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1695 return false;
1696
1697 /*
1698 * If there's only a single callback registered to a
1699 * function, and the ops has a trampoline registered
1700 * for it, then we can call it directly.
1701 */
1702 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1703 rec->flags |= FTRACE_FL_TRAMP;
1704 else
1705 /*
1706 * If we are adding another function callback
1707 * to this function, and the previous had a
1708 * custom trampoline in use, then we need to go
1709 * back to the default trampoline.
1710 */
1711 rec->flags &= ~FTRACE_FL_TRAMP;
1712
1713 /*
1714 * If any ops wants regs saved for this function
1715 * then all ops will get saved regs.
1716 */
1717 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1718 rec->flags |= FTRACE_FL_REGS;
1719 } else {
1720 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1721 return false;
1722 rec->flags--;
1723
1724 /*
1725 * If the rec had REGS enabled and the ops that is
1726 * being removed had REGS set, then see if there is
1727 * still any ops for this record that wants regs.
1728 * If not, we can stop recording them.
1729 */
1730 if (ftrace_rec_count(rec) > 0 &&
1731 rec->flags & FTRACE_FL_REGS &&
1732 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1733 if (!test_rec_ops_needs_regs(rec))
1734 rec->flags &= ~FTRACE_FL_REGS;
1735 }
1736
1737 /*
1738 * If the rec had TRAMP enabled, then it needs to
1739 * be cleared. As TRAMP can only be enabled iff
1740 * there is only a single ops attached to it.
1741 * In otherwords, always disable it on decrementing.
1742 * In the future, we may set it if rec count is
1743 * decremented to one, and the ops that is left
1744 * has a trampoline.
1745 */
1746 rec->flags &= ~FTRACE_FL_TRAMP;
1747
1748 /*
1749 * flags will be cleared in ftrace_check_record()
1750 * if rec count is zero.
1751 */
1752 }
1753 count++;
1754
1755 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1756 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1757
1758 /* Shortcut, if we handled all records, we are done. */
1759 if (!all && count == hash->count)
1760 return update;
1761 } while_for_each_ftrace_rec();
1762
1763 return update;
1764}
1765
1766static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1767 int filter_hash)
1768{
1769 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1770}
1771
1772static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1773 int filter_hash)
1774{
1775 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1776}
1777
1778static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1779 int filter_hash, int inc)
1780{
1781 struct ftrace_ops *op;
1782
1783 __ftrace_hash_rec_update(ops, filter_hash, inc);
1784
1785 if (ops->func_hash != &global_ops.local_hash)
1786 return;
1787
1788 /*
1789 * If the ops shares the global_ops hash, then we need to update
1790 * all ops that are enabled and use this hash.
1791 */
1792 do_for_each_ftrace_op(op, ftrace_ops_list) {
1793 /* Already done */
1794 if (op == ops)
1795 continue;
1796 if (op->func_hash == &global_ops.local_hash)
1797 __ftrace_hash_rec_update(op, filter_hash, inc);
1798 } while_for_each_ftrace_op(op);
1799}
1800
1801static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1802 int filter_hash)
1803{
1804 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1805}
1806
1807static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1808 int filter_hash)
1809{
1810 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1811}
1812
1813/*
1814 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1815 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1816 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1817 * Note that old_hash and new_hash has below meanings
1818 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1819 * - If the hash is EMPTY_HASH, it hits nothing
1820 * - Anything else hits the recs which match the hash entries.
1821 */
1822static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1823 struct ftrace_hash *old_hash,
1824 struct ftrace_hash *new_hash)
1825{
1826 struct ftrace_page *pg;
1827 struct dyn_ftrace *rec, *end = NULL;
1828 int in_old, in_new;
1829
1830 /* Only update if the ops has been registered */
1831 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1832 return 0;
1833
1834 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1835 return 0;
1836
1837 /*
1838 * Since the IPMODIFY is a very address sensitive action, we do not
1839 * allow ftrace_ops to set all functions to new hash.
1840 */
1841 if (!new_hash || !old_hash)
1842 return -EINVAL;
1843
1844 /* Update rec->flags */
1845 do_for_each_ftrace_rec(pg, rec) {
1846 /* We need to update only differences of filter_hash */
1847 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1848 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1849 if (in_old == in_new)
1850 continue;
1851
1852 if (in_new) {
1853 /* New entries must ensure no others are using it */
1854 if (rec->flags & FTRACE_FL_IPMODIFY)
1855 goto rollback;
1856 rec->flags |= FTRACE_FL_IPMODIFY;
1857 } else /* Removed entry */
1858 rec->flags &= ~FTRACE_FL_IPMODIFY;
1859 } while_for_each_ftrace_rec();
1860
1861 return 0;
1862
1863rollback:
1864 end = rec;
1865
1866 /* Roll back what we did above */
1867 do_for_each_ftrace_rec(pg, rec) {
1868 if (rec == end)
1869 goto err_out;
1870
1871 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1872 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1873 if (in_old == in_new)
1874 continue;
1875
1876 if (in_new)
1877 rec->flags &= ~FTRACE_FL_IPMODIFY;
1878 else
1879 rec->flags |= FTRACE_FL_IPMODIFY;
1880 } while_for_each_ftrace_rec();
1881
1882err_out:
1883 return -EBUSY;
1884}
1885
1886static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1887{
1888 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1889
1890 if (ftrace_hash_empty(hash))
1891 hash = NULL;
1892
1893 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1894}
1895
1896/* Disabling always succeeds */
1897static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1898{
1899 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1900
1901 if (ftrace_hash_empty(hash))
1902 hash = NULL;
1903
1904 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1905}
1906
1907static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1908 struct ftrace_hash *new_hash)
1909{
1910 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1911
1912 if (ftrace_hash_empty(old_hash))
1913 old_hash = NULL;
1914
1915 if (ftrace_hash_empty(new_hash))
1916 new_hash = NULL;
1917
1918 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1919}
1920
1921static void print_ip_ins(const char *fmt, const unsigned char *p)
1922{
1923 int i;
1924
1925 printk(KERN_CONT "%s", fmt);
1926
1927 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1928 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1929}
1930
1931static struct ftrace_ops *
1932ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1933static struct ftrace_ops *
1934ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1935
1936enum ftrace_bug_type ftrace_bug_type;
1937const void *ftrace_expected;
1938
1939static void print_bug_type(void)
1940{
1941 switch (ftrace_bug_type) {
1942 case FTRACE_BUG_UNKNOWN:
1943 break;
1944 case FTRACE_BUG_INIT:
1945 pr_info("Initializing ftrace call sites\n");
1946 break;
1947 case FTRACE_BUG_NOP:
1948 pr_info("Setting ftrace call site to NOP\n");
1949 break;
1950 case FTRACE_BUG_CALL:
1951 pr_info("Setting ftrace call site to call ftrace function\n");
1952 break;
1953 case FTRACE_BUG_UPDATE:
1954 pr_info("Updating ftrace call site to call a different ftrace function\n");
1955 break;
1956 }
1957}
1958
1959/**
1960 * ftrace_bug - report and shutdown function tracer
1961 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1962 * @rec: The record that failed
1963 *
1964 * The arch code that enables or disables the function tracing
1965 * can call ftrace_bug() when it has detected a problem in
1966 * modifying the code. @failed should be one of either:
1967 * EFAULT - if the problem happens on reading the @ip address
1968 * EINVAL - if what is read at @ip is not what was expected
1969 * EPERM - if the problem happens on writting to the @ip address
1970 */
1971void ftrace_bug(int failed, struct dyn_ftrace *rec)
1972{
1973 unsigned long ip = rec ? rec->ip : 0;
1974
1975 switch (failed) {
1976 case -EFAULT:
1977 FTRACE_WARN_ON_ONCE(1);
1978 pr_info("ftrace faulted on modifying ");
1979 print_ip_sym(ip);
1980 break;
1981 case -EINVAL:
1982 FTRACE_WARN_ON_ONCE(1);
1983 pr_info("ftrace failed to modify ");
1984 print_ip_sym(ip);
1985 print_ip_ins(" actual: ", (unsigned char *)ip);
1986 pr_cont("\n");
1987 if (ftrace_expected) {
1988 print_ip_ins(" expected: ", ftrace_expected);
1989 pr_cont("\n");
1990 }
1991 break;
1992 case -EPERM:
1993 FTRACE_WARN_ON_ONCE(1);
1994 pr_info("ftrace faulted on writing ");
1995 print_ip_sym(ip);
1996 break;
1997 default:
1998 FTRACE_WARN_ON_ONCE(1);
1999 pr_info("ftrace faulted on unknown error ");
2000 print_ip_sym(ip);
2001 }
2002 print_bug_type();
2003 if (rec) {
2004 struct ftrace_ops *ops = NULL;
2005
2006 pr_info("ftrace record flags: %lx\n", rec->flags);
2007 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2008 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2009 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2010 ops = ftrace_find_tramp_ops_any(rec);
2011 if (ops) {
2012 do {
2013 pr_cont("\ttramp: %pS (%pS)",
2014 (void *)ops->trampoline,
2015 (void *)ops->func);
2016 ops = ftrace_find_tramp_ops_next(rec, ops);
2017 } while (ops);
2018 } else
2019 pr_cont("\ttramp: ERROR!");
2020
2021 }
2022 ip = ftrace_get_addr_curr(rec);
2023 pr_cont("\n expected tramp: %lx\n", ip);
2024 }
2025}
2026
2027static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2028{
2029 unsigned long flag = 0UL;
2030
2031 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2032
2033 if (rec->flags & FTRACE_FL_DISABLED)
2034 return FTRACE_UPDATE_IGNORE;
2035
2036 /*
2037 * If we are updating calls:
2038 *
2039 * If the record has a ref count, then we need to enable it
2040 * because someone is using it.
2041 *
2042 * Otherwise we make sure its disabled.
2043 *
2044 * If we are disabling calls, then disable all records that
2045 * are enabled.
2046 */
2047 if (enable && ftrace_rec_count(rec))
2048 flag = FTRACE_FL_ENABLED;
2049
2050 /*
2051 * If enabling and the REGS flag does not match the REGS_EN, or
2052 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2053 * this record. Set flags to fail the compare against ENABLED.
2054 */
2055 if (flag) {
2056 if (!(rec->flags & FTRACE_FL_REGS) !=
2057 !(rec->flags & FTRACE_FL_REGS_EN))
2058 flag |= FTRACE_FL_REGS;
2059
2060 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2061 !(rec->flags & FTRACE_FL_TRAMP_EN))
2062 flag |= FTRACE_FL_TRAMP;
2063 }
2064
2065 /* If the state of this record hasn't changed, then do nothing */
2066 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2067 return FTRACE_UPDATE_IGNORE;
2068
2069 if (flag) {
2070 /* Save off if rec is being enabled (for return value) */
2071 flag ^= rec->flags & FTRACE_FL_ENABLED;
2072
2073 if (update) {
2074 rec->flags |= FTRACE_FL_ENABLED;
2075 if (flag & FTRACE_FL_REGS) {
2076 if (rec->flags & FTRACE_FL_REGS)
2077 rec->flags |= FTRACE_FL_REGS_EN;
2078 else
2079 rec->flags &= ~FTRACE_FL_REGS_EN;
2080 }
2081 if (flag & FTRACE_FL_TRAMP) {
2082 if (rec->flags & FTRACE_FL_TRAMP)
2083 rec->flags |= FTRACE_FL_TRAMP_EN;
2084 else
2085 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2086 }
2087 }
2088
2089 /*
2090 * If this record is being updated from a nop, then
2091 * return UPDATE_MAKE_CALL.
2092 * Otherwise,
2093 * return UPDATE_MODIFY_CALL to tell the caller to convert
2094 * from the save regs, to a non-save regs function or
2095 * vice versa, or from a trampoline call.
2096 */
2097 if (flag & FTRACE_FL_ENABLED) {
2098 ftrace_bug_type = FTRACE_BUG_CALL;
2099 return FTRACE_UPDATE_MAKE_CALL;
2100 }
2101
2102 ftrace_bug_type = FTRACE_BUG_UPDATE;
2103 return FTRACE_UPDATE_MODIFY_CALL;
2104 }
2105
2106 if (update) {
2107 /* If there's no more users, clear all flags */
2108 if (!ftrace_rec_count(rec))
2109 rec->flags = 0;
2110 else
2111 /*
2112 * Just disable the record, but keep the ops TRAMP
2113 * and REGS states. The _EN flags must be disabled though.
2114 */
2115 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2116 FTRACE_FL_REGS_EN);
2117 }
2118
2119 ftrace_bug_type = FTRACE_BUG_NOP;
2120 return FTRACE_UPDATE_MAKE_NOP;
2121}
2122
2123/**
2124 * ftrace_update_record, set a record that now is tracing or not
2125 * @rec: the record to update
2126 * @enable: set to 1 if the record is tracing, zero to force disable
2127 *
2128 * The records that represent all functions that can be traced need
2129 * to be updated when tracing has been enabled.
2130 */
2131int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2132{
2133 return ftrace_check_record(rec, enable, 1);
2134}
2135
2136/**
2137 * ftrace_test_record, check if the record has been enabled or not
2138 * @rec: the record to test
2139 * @enable: set to 1 to check if enabled, 0 if it is disabled
2140 *
2141 * The arch code may need to test if a record is already set to
2142 * tracing to determine how to modify the function code that it
2143 * represents.
2144 */
2145int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2146{
2147 return ftrace_check_record(rec, enable, 0);
2148}
2149
2150static struct ftrace_ops *
2151ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2152{
2153 struct ftrace_ops *op;
2154 unsigned long ip = rec->ip;
2155
2156 do_for_each_ftrace_op(op, ftrace_ops_list) {
2157
2158 if (!op->trampoline)
2159 continue;
2160
2161 if (hash_contains_ip(ip, op->func_hash))
2162 return op;
2163 } while_for_each_ftrace_op(op);
2164
2165 return NULL;
2166}
2167
2168static struct ftrace_ops *
2169ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2170 struct ftrace_ops *op)
2171{
2172 unsigned long ip = rec->ip;
2173
2174 while_for_each_ftrace_op(op) {
2175
2176 if (!op->trampoline)
2177 continue;
2178
2179 if (hash_contains_ip(ip, op->func_hash))
2180 return op;
2181 }
2182
2183 return NULL;
2184}
2185
2186static struct ftrace_ops *
2187ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2188{
2189 struct ftrace_ops *op;
2190 unsigned long ip = rec->ip;
2191
2192 /*
2193 * Need to check removed ops first.
2194 * If they are being removed, and this rec has a tramp,
2195 * and this rec is in the ops list, then it would be the
2196 * one with the tramp.
2197 */
2198 if (removed_ops) {
2199 if (hash_contains_ip(ip, &removed_ops->old_hash))
2200 return removed_ops;
2201 }
2202
2203 /*
2204 * Need to find the current trampoline for a rec.
2205 * Now, a trampoline is only attached to a rec if there
2206 * was a single 'ops' attached to it. But this can be called
2207 * when we are adding another op to the rec or removing the
2208 * current one. Thus, if the op is being added, we can
2209 * ignore it because it hasn't attached itself to the rec
2210 * yet.
2211 *
2212 * If an ops is being modified (hooking to different functions)
2213 * then we don't care about the new functions that are being
2214 * added, just the old ones (that are probably being removed).
2215 *
2216 * If we are adding an ops to a function that already is using
2217 * a trampoline, it needs to be removed (trampolines are only
2218 * for single ops connected), then an ops that is not being
2219 * modified also needs to be checked.
2220 */
2221 do_for_each_ftrace_op(op, ftrace_ops_list) {
2222
2223 if (!op->trampoline)
2224 continue;
2225
2226 /*
2227 * If the ops is being added, it hasn't gotten to
2228 * the point to be removed from this tree yet.
2229 */
2230 if (op->flags & FTRACE_OPS_FL_ADDING)
2231 continue;
2232
2233
2234 /*
2235 * If the ops is being modified and is in the old
2236 * hash, then it is probably being removed from this
2237 * function.
2238 */
2239 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2240 hash_contains_ip(ip, &op->old_hash))
2241 return op;
2242 /*
2243 * If the ops is not being added or modified, and it's
2244 * in its normal filter hash, then this must be the one
2245 * we want!
2246 */
2247 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2248 hash_contains_ip(ip, op->func_hash))
2249 return op;
2250
2251 } while_for_each_ftrace_op(op);
2252
2253 return NULL;
2254}
2255
2256static struct ftrace_ops *
2257ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2258{
2259 struct ftrace_ops *op;
2260 unsigned long ip = rec->ip;
2261
2262 do_for_each_ftrace_op(op, ftrace_ops_list) {
2263 /* pass rec in as regs to have non-NULL val */
2264 if (hash_contains_ip(ip, op->func_hash))
2265 return op;
2266 } while_for_each_ftrace_op(op);
2267
2268 return NULL;
2269}
2270
2271/**
2272 * ftrace_get_addr_new - Get the call address to set to
2273 * @rec: The ftrace record descriptor
2274 *
2275 * If the record has the FTRACE_FL_REGS set, that means that it
2276 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2277 * is not not set, then it wants to convert to the normal callback.
2278 *
2279 * Returns the address of the trampoline to set to
2280 */
2281unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2282{
2283 struct ftrace_ops *ops;
2284
2285 /* Trampolines take precedence over regs */
2286 if (rec->flags & FTRACE_FL_TRAMP) {
2287 ops = ftrace_find_tramp_ops_new(rec);
2288 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2289 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2290 (void *)rec->ip, (void *)rec->ip, rec->flags);
2291 /* Ftrace is shutting down, return anything */
2292 return (unsigned long)FTRACE_ADDR;
2293 }
2294 return ops->trampoline;
2295 }
2296
2297 if (rec->flags & FTRACE_FL_REGS)
2298 return (unsigned long)FTRACE_REGS_ADDR;
2299 else
2300 return (unsigned long)FTRACE_ADDR;
2301}
2302
2303/**
2304 * ftrace_get_addr_curr - Get the call address that is already there
2305 * @rec: The ftrace record descriptor
2306 *
2307 * The FTRACE_FL_REGS_EN is set when the record already points to
2308 * a function that saves all the regs. Basically the '_EN' version
2309 * represents the current state of the function.
2310 *
2311 * Returns the address of the trampoline that is currently being called
2312 */
2313unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2314{
2315 struct ftrace_ops *ops;
2316
2317 /* Trampolines take precedence over regs */
2318 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2319 ops = ftrace_find_tramp_ops_curr(rec);
2320 if (FTRACE_WARN_ON(!ops)) {
2321 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2322 (void *)rec->ip, (void *)rec->ip);
2323 /* Ftrace is shutting down, return anything */
2324 return (unsigned long)FTRACE_ADDR;
2325 }
2326 return ops->trampoline;
2327 }
2328
2329 if (rec->flags & FTRACE_FL_REGS_EN)
2330 return (unsigned long)FTRACE_REGS_ADDR;
2331 else
2332 return (unsigned long)FTRACE_ADDR;
2333}
2334
2335static int
2336__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2337{
2338 unsigned long ftrace_old_addr;
2339 unsigned long ftrace_addr;
2340 int ret;
2341
2342 ftrace_addr = ftrace_get_addr_new(rec);
2343
2344 /* This needs to be done before we call ftrace_update_record */
2345 ftrace_old_addr = ftrace_get_addr_curr(rec);
2346
2347 ret = ftrace_update_record(rec, enable);
2348
2349 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2350
2351 switch (ret) {
2352 case FTRACE_UPDATE_IGNORE:
2353 return 0;
2354
2355 case FTRACE_UPDATE_MAKE_CALL:
2356 ftrace_bug_type = FTRACE_BUG_CALL;
2357 return ftrace_make_call(rec, ftrace_addr);
2358
2359 case FTRACE_UPDATE_MAKE_NOP:
2360 ftrace_bug_type = FTRACE_BUG_NOP;
2361 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2362
2363 case FTRACE_UPDATE_MODIFY_CALL:
2364 ftrace_bug_type = FTRACE_BUG_UPDATE;
2365 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2366 }
2367
2368 return -1; /* unknow ftrace bug */
2369}
2370
2371void __weak ftrace_replace_code(int enable)
2372{
2373 struct dyn_ftrace *rec;
2374 struct ftrace_page *pg;
2375 int failed;
2376
2377 if (unlikely(ftrace_disabled))
2378 return;
2379
2380 do_for_each_ftrace_rec(pg, rec) {
2381 failed = __ftrace_replace_code(rec, enable);
2382 if (failed) {
2383 ftrace_bug(failed, rec);
2384 /* Stop processing */
2385 return;
2386 }
2387 } while_for_each_ftrace_rec();
2388}
2389
2390struct ftrace_rec_iter {
2391 struct ftrace_page *pg;
2392 int index;
2393};
2394
2395/**
2396 * ftrace_rec_iter_start, start up iterating over traced functions
2397 *
2398 * Returns an iterator handle that is used to iterate over all
2399 * the records that represent address locations where functions
2400 * are traced.
2401 *
2402 * May return NULL if no records are available.
2403 */
2404struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2405{
2406 /*
2407 * We only use a single iterator.
2408 * Protected by the ftrace_lock mutex.
2409 */
2410 static struct ftrace_rec_iter ftrace_rec_iter;
2411 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2412
2413 iter->pg = ftrace_pages_start;
2414 iter->index = 0;
2415
2416 /* Could have empty pages */
2417 while (iter->pg && !iter->pg->index)
2418 iter->pg = iter->pg->next;
2419
2420 if (!iter->pg)
2421 return NULL;
2422
2423 return iter;
2424}
2425
2426/**
2427 * ftrace_rec_iter_next, get the next record to process.
2428 * @iter: The handle to the iterator.
2429 *
2430 * Returns the next iterator after the given iterator @iter.
2431 */
2432struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2433{
2434 iter->index++;
2435
2436 if (iter->index >= iter->pg->index) {
2437 iter->pg = iter->pg->next;
2438 iter->index = 0;
2439
2440 /* Could have empty pages */
2441 while (iter->pg && !iter->pg->index)
2442 iter->pg = iter->pg->next;
2443 }
2444
2445 if (!iter->pg)
2446 return NULL;
2447
2448 return iter;
2449}
2450
2451/**
2452 * ftrace_rec_iter_record, get the record at the iterator location
2453 * @iter: The current iterator location
2454 *
2455 * Returns the record that the current @iter is at.
2456 */
2457struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2458{
2459 return &iter->pg->records[iter->index];
2460}
2461
2462static int
2463ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2464{
2465 int ret;
2466
2467 if (unlikely(ftrace_disabled))
2468 return 0;
2469
2470 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2471 if (ret) {
2472 ftrace_bug_type = FTRACE_BUG_INIT;
2473 ftrace_bug(ret, rec);
2474 return 0;
2475 }
2476 return 1;
2477}
2478
2479/*
2480 * archs can override this function if they must do something
2481 * before the modifying code is performed.
2482 */
2483int __weak ftrace_arch_code_modify_prepare(void)
2484{
2485 return 0;
2486}
2487
2488/*
2489 * archs can override this function if they must do something
2490 * after the modifying code is performed.
2491 */
2492int __weak ftrace_arch_code_modify_post_process(void)
2493{
2494 return 0;
2495}
2496
2497void ftrace_modify_all_code(int command)
2498{
2499 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2500 int err = 0;
2501
2502 /*
2503 * If the ftrace_caller calls a ftrace_ops func directly,
2504 * we need to make sure that it only traces functions it
2505 * expects to trace. When doing the switch of functions,
2506 * we need to update to the ftrace_ops_list_func first
2507 * before the transition between old and new calls are set,
2508 * as the ftrace_ops_list_func will check the ops hashes
2509 * to make sure the ops are having the right functions
2510 * traced.
2511 */
2512 if (update) {
2513 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2514 if (FTRACE_WARN_ON(err))
2515 return;
2516 }
2517
2518 if (command & FTRACE_UPDATE_CALLS)
2519 ftrace_replace_code(1);
2520 else if (command & FTRACE_DISABLE_CALLS)
2521 ftrace_replace_code(0);
2522
2523 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2524 function_trace_op = set_function_trace_op;
2525 smp_wmb();
2526 /* If irqs are disabled, we are in stop machine */
2527 if (!irqs_disabled())
2528 smp_call_function(ftrace_sync_ipi, NULL, 1);
2529 err = ftrace_update_ftrace_func(ftrace_trace_function);
2530 if (FTRACE_WARN_ON(err))
2531 return;
2532 }
2533
2534 if (command & FTRACE_START_FUNC_RET)
2535 err = ftrace_enable_ftrace_graph_caller();
2536 else if (command & FTRACE_STOP_FUNC_RET)
2537 err = ftrace_disable_ftrace_graph_caller();
2538 FTRACE_WARN_ON(err);
2539}
2540
2541static int __ftrace_modify_code(void *data)
2542{
2543 int *command = data;
2544
2545 ftrace_modify_all_code(*command);
2546
2547 return 0;
2548}
2549
2550/**
2551 * ftrace_run_stop_machine, go back to the stop machine method
2552 * @command: The command to tell ftrace what to do
2553 *
2554 * If an arch needs to fall back to the stop machine method, the
2555 * it can call this function.
2556 */
2557void ftrace_run_stop_machine(int command)
2558{
2559 stop_machine(__ftrace_modify_code, &command, NULL);
2560}
2561
2562/**
2563 * arch_ftrace_update_code, modify the code to trace or not trace
2564 * @command: The command that needs to be done
2565 *
2566 * Archs can override this function if it does not need to
2567 * run stop_machine() to modify code.
2568 */
2569void __weak arch_ftrace_update_code(int command)
2570{
2571 ftrace_run_stop_machine(command);
2572}
2573
2574static void ftrace_run_update_code(int command)
2575{
2576 int ret;
2577
2578 ret = ftrace_arch_code_modify_prepare();
2579 FTRACE_WARN_ON(ret);
2580 if (ret)
2581 return;
2582
2583 /*
2584 * By default we use stop_machine() to modify the code.
2585 * But archs can do what ever they want as long as it
2586 * is safe. The stop_machine() is the safest, but also
2587 * produces the most overhead.
2588 */
2589 arch_ftrace_update_code(command);
2590
2591 ret = ftrace_arch_code_modify_post_process();
2592 FTRACE_WARN_ON(ret);
2593}
2594
2595static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2596 struct ftrace_ops_hash *old_hash)
2597{
2598 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2599 ops->old_hash.filter_hash = old_hash->filter_hash;
2600 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2601 ftrace_run_update_code(command);
2602 ops->old_hash.filter_hash = NULL;
2603 ops->old_hash.notrace_hash = NULL;
2604 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2605}
2606
2607static ftrace_func_t saved_ftrace_func;
2608static int ftrace_start_up;
2609
2610void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2611{
2612}
2613
2614static void per_cpu_ops_free(struct ftrace_ops *ops)
2615{
2616 free_percpu(ops->disabled);
2617}
2618
2619static void ftrace_startup_enable(int command)
2620{
2621 if (saved_ftrace_func != ftrace_trace_function) {
2622 saved_ftrace_func = ftrace_trace_function;
2623 command |= FTRACE_UPDATE_TRACE_FUNC;
2624 }
2625
2626 if (!command || !ftrace_enabled)
2627 return;
2628
2629 ftrace_run_update_code(command);
2630}
2631
2632static void ftrace_startup_all(int command)
2633{
2634 update_all_ops = true;
2635 ftrace_startup_enable(command);
2636 update_all_ops = false;
2637}
2638
2639static int ftrace_startup(struct ftrace_ops *ops, int command)
2640{
2641 int ret;
2642
2643 if (unlikely(ftrace_disabled))
2644 return -ENODEV;
2645
2646 ret = __register_ftrace_function(ops);
2647 if (ret)
2648 return ret;
2649
2650 ftrace_start_up++;
2651
2652 /*
2653 * Note that ftrace probes uses this to start up
2654 * and modify functions it will probe. But we still
2655 * set the ADDING flag for modification, as probes
2656 * do not have trampolines. If they add them in the
2657 * future, then the probes will need to distinguish
2658 * between adding and updating probes.
2659 */
2660 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2661
2662 ret = ftrace_hash_ipmodify_enable(ops);
2663 if (ret < 0) {
2664 /* Rollback registration process */
2665 __unregister_ftrace_function(ops);
2666 ftrace_start_up--;
2667 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2668 return ret;
2669 }
2670
2671 if (ftrace_hash_rec_enable(ops, 1))
2672 command |= FTRACE_UPDATE_CALLS;
2673
2674 ftrace_startup_enable(command);
2675
2676 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2677
2678 return 0;
2679}
2680
2681static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2682{
2683 int ret;
2684
2685 if (unlikely(ftrace_disabled))
2686 return -ENODEV;
2687
2688 ret = __unregister_ftrace_function(ops);
2689 if (ret)
2690 return ret;
2691
2692 ftrace_start_up--;
2693 /*
2694 * Just warn in case of unbalance, no need to kill ftrace, it's not
2695 * critical but the ftrace_call callers may be never nopped again after
2696 * further ftrace uses.
2697 */
2698 WARN_ON_ONCE(ftrace_start_up < 0);
2699
2700 /* Disabling ipmodify never fails */
2701 ftrace_hash_ipmodify_disable(ops);
2702
2703 if (ftrace_hash_rec_disable(ops, 1))
2704 command |= FTRACE_UPDATE_CALLS;
2705
2706 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2707
2708 if (saved_ftrace_func != ftrace_trace_function) {
2709 saved_ftrace_func = ftrace_trace_function;
2710 command |= FTRACE_UPDATE_TRACE_FUNC;
2711 }
2712
2713 if (!command || !ftrace_enabled) {
2714 /*
2715 * If these are per_cpu ops, they still need their
2716 * per_cpu field freed. Since, function tracing is
2717 * not currently active, we can just free them
2718 * without synchronizing all CPUs.
2719 */
2720 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2721 per_cpu_ops_free(ops);
2722 return 0;
2723 }
2724
2725 /*
2726 * If the ops uses a trampoline, then it needs to be
2727 * tested first on update.
2728 */
2729 ops->flags |= FTRACE_OPS_FL_REMOVING;
2730 removed_ops = ops;
2731
2732 /* The trampoline logic checks the old hashes */
2733 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2734 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2735
2736 ftrace_run_update_code(command);
2737
2738 /*
2739 * If there's no more ops registered with ftrace, run a
2740 * sanity check to make sure all rec flags are cleared.
2741 */
2742 if (ftrace_ops_list == &ftrace_list_end) {
2743 struct ftrace_page *pg;
2744 struct dyn_ftrace *rec;
2745
2746 do_for_each_ftrace_rec(pg, rec) {
2747 if (FTRACE_WARN_ON_ONCE(rec->flags))
2748 pr_warn(" %pS flags:%lx\n",
2749 (void *)rec->ip, rec->flags);
2750 } while_for_each_ftrace_rec();
2751 }
2752
2753 ops->old_hash.filter_hash = NULL;
2754 ops->old_hash.notrace_hash = NULL;
2755
2756 removed_ops = NULL;
2757 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2758
2759 /*
2760 * Dynamic ops may be freed, we must make sure that all
2761 * callers are done before leaving this function.
2762 * The same goes for freeing the per_cpu data of the per_cpu
2763 * ops.
2764 *
2765 * Again, normal synchronize_sched() is not good enough.
2766 * We need to do a hard force of sched synchronization.
2767 * This is because we use preempt_disable() to do RCU, but
2768 * the function tracers can be called where RCU is not watching
2769 * (like before user_exit()). We can not rely on the RCU
2770 * infrastructure to do the synchronization, thus we must do it
2771 * ourselves.
2772 */
2773 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2774 schedule_on_each_cpu(ftrace_sync);
2775
2776 arch_ftrace_trampoline_free(ops);
2777
2778 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2779 per_cpu_ops_free(ops);
2780 }
2781
2782 return 0;
2783}
2784
2785static void ftrace_startup_sysctl(void)
2786{
2787 int command;
2788
2789 if (unlikely(ftrace_disabled))
2790 return;
2791
2792 /* Force update next time */
2793 saved_ftrace_func = NULL;
2794 /* ftrace_start_up is true if we want ftrace running */
2795 if (ftrace_start_up) {
2796 command = FTRACE_UPDATE_CALLS;
2797 if (ftrace_graph_active)
2798 command |= FTRACE_START_FUNC_RET;
2799 ftrace_startup_enable(command);
2800 }
2801}
2802
2803static void ftrace_shutdown_sysctl(void)
2804{
2805 int command;
2806
2807 if (unlikely(ftrace_disabled))
2808 return;
2809
2810 /* ftrace_start_up is true if ftrace is running */
2811 if (ftrace_start_up) {
2812 command = FTRACE_DISABLE_CALLS;
2813 if (ftrace_graph_active)
2814 command |= FTRACE_STOP_FUNC_RET;
2815 ftrace_run_update_code(command);
2816 }
2817}
2818
2819static cycle_t ftrace_update_time;
2820unsigned long ftrace_update_tot_cnt;
2821
2822static inline int ops_traces_mod(struct ftrace_ops *ops)
2823{
2824 /*
2825 * Filter_hash being empty will default to trace module.
2826 * But notrace hash requires a test of individual module functions.
2827 */
2828 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2829 ftrace_hash_empty(ops->func_hash->notrace_hash);
2830}
2831
2832/*
2833 * Check if the current ops references the record.
2834 *
2835 * If the ops traces all functions, then it was already accounted for.
2836 * If the ops does not trace the current record function, skip it.
2837 * If the ops ignores the function via notrace filter, skip it.
2838 */
2839static inline bool
2840ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2841{
2842 /* If ops isn't enabled, ignore it */
2843 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2844 return 0;
2845
2846 /* If ops traces all then it includes this function */
2847 if (ops_traces_mod(ops))
2848 return 1;
2849
2850 /* The function must be in the filter */
2851 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2852 !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2853 return 0;
2854
2855 /* If in notrace hash, we ignore it too */
2856 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2857 return 0;
2858
2859 return 1;
2860}
2861
2862static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2863{
2864 struct ftrace_page *pg;
2865 struct dyn_ftrace *p;
2866 cycle_t start, stop;
2867 unsigned long update_cnt = 0;
2868 unsigned long rec_flags = 0;
2869 int i;
2870
2871 start = ftrace_now(raw_smp_processor_id());
2872
2873 /*
2874 * When a module is loaded, this function is called to convert
2875 * the calls to mcount in its text to nops, and also to create
2876 * an entry in the ftrace data. Now, if ftrace is activated
2877 * after this call, but before the module sets its text to
2878 * read-only, the modification of enabling ftrace can fail if
2879 * the read-only is done while ftrace is converting the calls.
2880 * To prevent this, the module's records are set as disabled
2881 * and will be enabled after the call to set the module's text
2882 * to read-only.
2883 */
2884 if (mod)
2885 rec_flags |= FTRACE_FL_DISABLED;
2886
2887 for (pg = new_pgs; pg; pg = pg->next) {
2888
2889 for (i = 0; i < pg->index; i++) {
2890
2891 /* If something went wrong, bail without enabling anything */
2892 if (unlikely(ftrace_disabled))
2893 return -1;
2894
2895 p = &pg->records[i];
2896 p->flags = rec_flags;
2897
2898 /*
2899 * Do the initial record conversion from mcount jump
2900 * to the NOP instructions.
2901 */
2902 if (!ftrace_code_disable(mod, p))
2903 break;
2904
2905 update_cnt++;
2906 }
2907 }
2908
2909 stop = ftrace_now(raw_smp_processor_id());
2910 ftrace_update_time = stop - start;
2911 ftrace_update_tot_cnt += update_cnt;
2912
2913 return 0;
2914}
2915
2916static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2917{
2918 int order;
2919 int cnt;
2920
2921 if (WARN_ON(!count))
2922 return -EINVAL;
2923
2924 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2925
2926 /*
2927 * We want to fill as much as possible. No more than a page
2928 * may be empty.
2929 */
2930 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2931 order--;
2932
2933 again:
2934 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2935
2936 if (!pg->records) {
2937 /* if we can't allocate this size, try something smaller */
2938 if (!order)
2939 return -ENOMEM;
2940 order >>= 1;
2941 goto again;
2942 }
2943
2944 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2945 pg->size = cnt;
2946
2947 if (cnt > count)
2948 cnt = count;
2949
2950 return cnt;
2951}
2952
2953static struct ftrace_page *
2954ftrace_allocate_pages(unsigned long num_to_init)
2955{
2956 struct ftrace_page *start_pg;
2957 struct ftrace_page *pg;
2958 int order;
2959 int cnt;
2960
2961 if (!num_to_init)
2962 return 0;
2963
2964 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2965 if (!pg)
2966 return NULL;
2967
2968 /*
2969 * Try to allocate as much as possible in one continues
2970 * location that fills in all of the space. We want to
2971 * waste as little space as possible.
2972 */
2973 for (;;) {
2974 cnt = ftrace_allocate_records(pg, num_to_init);
2975 if (cnt < 0)
2976 goto free_pages;
2977
2978 num_to_init -= cnt;
2979 if (!num_to_init)
2980 break;
2981
2982 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2983 if (!pg->next)
2984 goto free_pages;
2985
2986 pg = pg->next;
2987 }
2988
2989 return start_pg;
2990
2991 free_pages:
2992 pg = start_pg;
2993 while (pg) {
2994 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2995 free_pages((unsigned long)pg->records, order);
2996 start_pg = pg->next;
2997 kfree(pg);
2998 pg = start_pg;
2999 }
3000 pr_info("ftrace: FAILED to allocate memory for functions\n");
3001 return NULL;
3002}
3003
3004#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3005
3006struct ftrace_iterator {
3007 loff_t pos;
3008 loff_t func_pos;
3009 struct ftrace_page *pg;
3010 struct dyn_ftrace *func;
3011 struct ftrace_func_probe *probe;
3012 struct trace_parser parser;
3013 struct ftrace_hash *hash;
3014 struct ftrace_ops *ops;
3015 int hidx;
3016 int idx;
3017 unsigned flags;
3018};
3019
3020static void *
3021t_hash_next(struct seq_file *m, loff_t *pos)
3022{
3023 struct ftrace_iterator *iter = m->private;
3024 struct hlist_node *hnd = NULL;
3025 struct hlist_head *hhd;
3026
3027 (*pos)++;
3028 iter->pos = *pos;
3029
3030 if (iter->probe)
3031 hnd = &iter->probe->node;
3032 retry:
3033 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3034 return NULL;
3035
3036 hhd = &ftrace_func_hash[iter->hidx];
3037
3038 if (hlist_empty(hhd)) {
3039 iter->hidx++;
3040 hnd = NULL;
3041 goto retry;
3042 }
3043
3044 if (!hnd)
3045 hnd = hhd->first;
3046 else {
3047 hnd = hnd->next;
3048 if (!hnd) {
3049 iter->hidx++;
3050 goto retry;
3051 }
3052 }
3053
3054 if (WARN_ON_ONCE(!hnd))
3055 return NULL;
3056
3057 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3058
3059 return iter;
3060}
3061
3062static void *t_hash_start(struct seq_file *m, loff_t *pos)
3063{
3064 struct ftrace_iterator *iter = m->private;
3065 void *p = NULL;
3066 loff_t l;
3067
3068 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3069 return NULL;
3070
3071 if (iter->func_pos > *pos)
3072 return NULL;
3073
3074 iter->hidx = 0;
3075 for (l = 0; l <= (*pos - iter->func_pos); ) {
3076 p = t_hash_next(m, &l);
3077 if (!p)
3078 break;
3079 }
3080 if (!p)
3081 return NULL;
3082
3083 /* Only set this if we have an item */
3084 iter->flags |= FTRACE_ITER_HASH;
3085
3086 return iter;
3087}
3088
3089static int
3090t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3091{
3092 struct ftrace_func_probe *rec;
3093
3094 rec = iter->probe;
3095 if (WARN_ON_ONCE(!rec))
3096 return -EIO;
3097
3098 if (rec->ops->print)
3099 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3100
3101 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3102
3103 if (rec->data)
3104 seq_printf(m, ":%p", rec->data);
3105 seq_putc(m, '\n');
3106
3107 return 0;
3108}
3109
3110static void *
3111t_next(struct seq_file *m, void *v, loff_t *pos)
3112{
3113 struct ftrace_iterator *iter = m->private;
3114 struct ftrace_ops *ops = iter->ops;
3115 struct dyn_ftrace *rec = NULL;
3116
3117 if (unlikely(ftrace_disabled))
3118 return NULL;
3119
3120 if (iter->flags & FTRACE_ITER_HASH)
3121 return t_hash_next(m, pos);
3122
3123 (*pos)++;
3124 iter->pos = iter->func_pos = *pos;
3125
3126 if (iter->flags & FTRACE_ITER_PRINTALL)
3127 return t_hash_start(m, pos);
3128
3129 retry:
3130 if (iter->idx >= iter->pg->index) {
3131 if (iter->pg->next) {
3132 iter->pg = iter->pg->next;
3133 iter->idx = 0;
3134 goto retry;
3135 }
3136 } else {
3137 rec = &iter->pg->records[iter->idx++];
3138 if (((iter->flags & FTRACE_ITER_FILTER) &&
3139 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3140
3141 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3142 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3143
3144 ((iter->flags & FTRACE_ITER_ENABLED) &&
3145 !(rec->flags & FTRACE_FL_ENABLED))) {
3146
3147 rec = NULL;
3148 goto retry;
3149 }
3150 }
3151
3152 if (!rec)
3153 return t_hash_start(m, pos);
3154
3155 iter->func = rec;
3156
3157 return iter;
3158}
3159
3160static void reset_iter_read(struct ftrace_iterator *iter)
3161{
3162 iter->pos = 0;
3163 iter->func_pos = 0;
3164 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3165}
3166
3167static void *t_start(struct seq_file *m, loff_t *pos)
3168{
3169 struct ftrace_iterator *iter = m->private;
3170 struct ftrace_ops *ops = iter->ops;
3171 void *p = NULL;
3172 loff_t l;
3173
3174 mutex_lock(&ftrace_lock);
3175
3176 if (unlikely(ftrace_disabled))
3177 return NULL;
3178
3179 /*
3180 * If an lseek was done, then reset and start from beginning.
3181 */
3182 if (*pos < iter->pos)
3183 reset_iter_read(iter);
3184
3185 /*
3186 * For set_ftrace_filter reading, if we have the filter
3187 * off, we can short cut and just print out that all
3188 * functions are enabled.
3189 */
3190 if ((iter->flags & FTRACE_ITER_FILTER &&
3191 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3192 (iter->flags & FTRACE_ITER_NOTRACE &&
3193 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3194 if (*pos > 0)
3195 return t_hash_start(m, pos);
3196 iter->flags |= FTRACE_ITER_PRINTALL;
3197 /* reset in case of seek/pread */
3198 iter->flags &= ~FTRACE_ITER_HASH;
3199 return iter;
3200 }
3201
3202 if (iter->flags & FTRACE_ITER_HASH)
3203 return t_hash_start(m, pos);
3204
3205 /*
3206 * Unfortunately, we need to restart at ftrace_pages_start
3207 * every time we let go of the ftrace_mutex. This is because
3208 * those pointers can change without the lock.
3209 */
3210 iter->pg = ftrace_pages_start;
3211 iter->idx = 0;
3212 for (l = 0; l <= *pos; ) {
3213 p = t_next(m, p, &l);
3214 if (!p)
3215 break;
3216 }
3217
3218 if (!p)
3219 return t_hash_start(m, pos);
3220
3221 return iter;
3222}
3223
3224static void t_stop(struct seq_file *m, void *p)
3225{
3226 mutex_unlock(&ftrace_lock);
3227}
3228
3229void * __weak
3230arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3231{
3232 return NULL;
3233}
3234
3235static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3236 struct dyn_ftrace *rec)
3237{
3238 void *ptr;
3239
3240 ptr = arch_ftrace_trampoline_func(ops, rec);
3241 if (ptr)
3242 seq_printf(m, " ->%pS", ptr);
3243}
3244
3245static int t_show(struct seq_file *m, void *v)
3246{
3247 struct ftrace_iterator *iter = m->private;
3248 struct dyn_ftrace *rec;
3249
3250 if (iter->flags & FTRACE_ITER_HASH)
3251 return t_hash_show(m, iter);
3252
3253 if (iter->flags & FTRACE_ITER_PRINTALL) {
3254 if (iter->flags & FTRACE_ITER_NOTRACE)
3255 seq_puts(m, "#### no functions disabled ####\n");
3256 else
3257 seq_puts(m, "#### all functions enabled ####\n");
3258 return 0;
3259 }
3260
3261 rec = iter->func;
3262
3263 if (!rec)
3264 return 0;
3265
3266 seq_printf(m, "%ps", (void *)rec->ip);
3267 if (iter->flags & FTRACE_ITER_ENABLED) {
3268 struct ftrace_ops *ops;
3269
3270 seq_printf(m, " (%ld)%s%s",
3271 ftrace_rec_count(rec),
3272 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3273 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3274 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3275 ops = ftrace_find_tramp_ops_any(rec);
3276 if (ops) {
3277 do {
3278 seq_printf(m, "\ttramp: %pS (%pS)",
3279 (void *)ops->trampoline,
3280 (void *)ops->func);
3281 add_trampoline_func(m, ops, rec);
3282 ops = ftrace_find_tramp_ops_next(rec, ops);
3283 } while (ops);
3284 } else
3285 seq_puts(m, "\ttramp: ERROR!");
3286 } else {
3287 add_trampoline_func(m, NULL, rec);
3288 }
3289 }
3290
3291 seq_putc(m, '\n');
3292
3293 return 0;
3294}
3295
3296static const struct seq_operations show_ftrace_seq_ops = {
3297 .start = t_start,
3298 .next = t_next,
3299 .stop = t_stop,
3300 .show = t_show,
3301};
3302
3303static int
3304ftrace_avail_open(struct inode *inode, struct file *file)
3305{
3306 struct ftrace_iterator *iter;
3307
3308 if (unlikely(ftrace_disabled))
3309 return -ENODEV;
3310
3311 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3312 if (iter) {
3313 iter->pg = ftrace_pages_start;
3314 iter->ops = &global_ops;
3315 }
3316
3317 return iter ? 0 : -ENOMEM;
3318}
3319
3320static int
3321ftrace_enabled_open(struct inode *inode, struct file *file)
3322{
3323 struct ftrace_iterator *iter;
3324
3325 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3326 if (iter) {
3327 iter->pg = ftrace_pages_start;
3328 iter->flags = FTRACE_ITER_ENABLED;
3329 iter->ops = &global_ops;
3330 }
3331
3332 return iter ? 0 : -ENOMEM;
3333}
3334
3335/**
3336 * ftrace_regex_open - initialize function tracer filter files
3337 * @ops: The ftrace_ops that hold the hash filters
3338 * @flag: The type of filter to process
3339 * @inode: The inode, usually passed in to your open routine
3340 * @file: The file, usually passed in to your open routine
3341 *
3342 * ftrace_regex_open() initializes the filter files for the
3343 * @ops. Depending on @flag it may process the filter hash or
3344 * the notrace hash of @ops. With this called from the open
3345 * routine, you can use ftrace_filter_write() for the write
3346 * routine if @flag has FTRACE_ITER_FILTER set, or
3347 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3348 * tracing_lseek() should be used as the lseek routine, and
3349 * release must call ftrace_regex_release().
3350 */
3351int
3352ftrace_regex_open(struct ftrace_ops *ops, int flag,
3353 struct inode *inode, struct file *file)
3354{
3355 struct ftrace_iterator *iter;
3356 struct ftrace_hash *hash;
3357 int ret = 0;
3358
3359 ftrace_ops_init(ops);
3360
3361 if (unlikely(ftrace_disabled))
3362 return -ENODEV;
3363
3364 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3365 if (!iter)
3366 return -ENOMEM;
3367
3368 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3369 kfree(iter);
3370 return -ENOMEM;
3371 }
3372
3373 iter->ops = ops;
3374 iter->flags = flag;
3375
3376 mutex_lock(&ops->func_hash->regex_lock);
3377
3378 if (flag & FTRACE_ITER_NOTRACE)
3379 hash = ops->func_hash->notrace_hash;
3380 else
3381 hash = ops->func_hash->filter_hash;
3382
3383 if (file->f_mode & FMODE_WRITE) {
3384 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3385
3386 if (file->f_flags & O_TRUNC)
3387 iter->hash = alloc_ftrace_hash(size_bits);
3388 else
3389 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3390
3391 if (!iter->hash) {
3392 trace_parser_put(&iter->parser);
3393 kfree(iter);
3394 ret = -ENOMEM;
3395 goto out_unlock;
3396 }
3397 }
3398
3399 if (file->f_mode & FMODE_READ) {
3400 iter->pg = ftrace_pages_start;
3401
3402 ret = seq_open(file, &show_ftrace_seq_ops);
3403 if (!ret) {
3404 struct seq_file *m = file->private_data;
3405 m->private = iter;
3406 } else {
3407 /* Failed */
3408 free_ftrace_hash(iter->hash);
3409 trace_parser_put(&iter->parser);
3410 kfree(iter);
3411 }
3412 } else
3413 file->private_data = iter;
3414
3415 out_unlock:
3416 mutex_unlock(&ops->func_hash->regex_lock);
3417
3418 return ret;
3419}
3420
3421static int
3422ftrace_filter_open(struct inode *inode, struct file *file)
3423{
3424 struct ftrace_ops *ops = inode->i_private;
3425
3426 return ftrace_regex_open(ops,
3427 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3428 inode, file);
3429}
3430
3431static int
3432ftrace_notrace_open(struct inode *inode, struct file *file)
3433{
3434 struct ftrace_ops *ops = inode->i_private;
3435
3436 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3437 inode, file);
3438}
3439
3440/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3441struct ftrace_glob {
3442 char *search;
3443 unsigned len;
3444 int type;
3445};
3446
3447static int ftrace_match(char *str, struct ftrace_glob *g)
3448{
3449 int matched = 0;
3450 int slen;
3451
3452 switch (g->type) {
3453 case MATCH_FULL:
3454 if (strcmp(str, g->search) == 0)
3455 matched = 1;
3456 break;
3457 case MATCH_FRONT_ONLY:
3458 if (strncmp(str, g->search, g->len) == 0)
3459 matched = 1;
3460 break;
3461 case MATCH_MIDDLE_ONLY:
3462 if (strstr(str, g->search))
3463 matched = 1;
3464 break;
3465 case MATCH_END_ONLY:
3466 slen = strlen(str);
3467 if (slen >= g->len &&
3468 memcmp(str + slen - g->len, g->search, g->len) == 0)
3469 matched = 1;
3470 break;
3471 }
3472
3473 return matched;
3474}
3475
3476static int
3477enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3478{
3479 struct ftrace_func_entry *entry;
3480 int ret = 0;
3481
3482 entry = ftrace_lookup_ip(hash, rec->ip);
3483 if (clear_filter) {
3484 /* Do nothing if it doesn't exist */
3485 if (!entry)
3486 return 0;
3487
3488 free_hash_entry(hash, entry);
3489 } else {
3490 /* Do nothing if it exists */
3491 if (entry)
3492 return 0;
3493
3494 ret = add_hash_entry(hash, rec->ip);
3495 }
3496 return ret;
3497}
3498
3499static int
3500ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3501 struct ftrace_glob *mod_g, int exclude_mod)
3502{
3503 char str[KSYM_SYMBOL_LEN];
3504 char *modname;
3505
3506 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3507
3508 if (mod_g) {
3509 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3510
3511 /* blank module name to match all modules */
3512 if (!mod_g->len) {
3513 /* blank module globbing: modname xor exclude_mod */
3514 if ((!exclude_mod) != (!modname))
3515 goto func_match;
3516 return 0;
3517 }
3518
3519 /* not matching the module */
3520 if (!modname || !mod_matches) {
3521 if (exclude_mod)
3522 goto func_match;
3523 else
3524 return 0;
3525 }
3526
3527 if (mod_matches && exclude_mod)
3528 return 0;
3529
3530func_match:
3531 /* blank search means to match all funcs in the mod */
3532 if (!func_g->len)
3533 return 1;
3534 }
3535
3536 return ftrace_match(str, func_g);
3537}
3538
3539static int
3540match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3541{
3542 struct ftrace_page *pg;
3543 struct dyn_ftrace *rec;
3544 struct ftrace_glob func_g = { .type = MATCH_FULL };
3545 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3546 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3547 int exclude_mod = 0;
3548 int found = 0;
3549 int ret;
3550 int clear_filter;
3551
3552 if (func) {
3553 func_g.type = filter_parse_regex(func, len, &func_g.search,
3554 &clear_filter);
3555 func_g.len = strlen(func_g.search);
3556 }
3557
3558 if (mod) {
3559 mod_g.type = filter_parse_regex(mod, strlen(mod),
3560 &mod_g.search, &exclude_mod);
3561 mod_g.len = strlen(mod_g.search);
3562 }
3563
3564 mutex_lock(&ftrace_lock);
3565
3566 if (unlikely(ftrace_disabled))
3567 goto out_unlock;
3568
3569 do_for_each_ftrace_rec(pg, rec) {
3570 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3571 ret = enter_record(hash, rec, clear_filter);
3572 if (ret < 0) {
3573 found = ret;
3574 goto out_unlock;
3575 }
3576 found = 1;
3577 }
3578 } while_for_each_ftrace_rec();
3579 out_unlock:
3580 mutex_unlock(&ftrace_lock);
3581
3582 return found;
3583}
3584
3585static int
3586ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3587{
3588 return match_records(hash, buff, len, NULL);
3589}
3590
3591
3592/*
3593 * We register the module command as a template to show others how
3594 * to register the a command as well.
3595 */
3596
3597static int
3598ftrace_mod_callback(struct ftrace_hash *hash,
3599 char *func, char *cmd, char *module, int enable)
3600{
3601 int ret;
3602
3603 /*
3604 * cmd == 'mod' because we only registered this func
3605 * for the 'mod' ftrace_func_command.
3606 * But if you register one func with multiple commands,
3607 * you can tell which command was used by the cmd
3608 * parameter.
3609 */
3610 ret = match_records(hash, func, strlen(func), module);
3611 if (!ret)
3612 return -EINVAL;
3613 if (ret < 0)
3614 return ret;
3615 return 0;
3616}
3617
3618static struct ftrace_func_command ftrace_mod_cmd = {
3619 .name = "mod",
3620 .func = ftrace_mod_callback,
3621};
3622
3623static int __init ftrace_mod_cmd_init(void)
3624{
3625 return register_ftrace_command(&ftrace_mod_cmd);
3626}
3627core_initcall(ftrace_mod_cmd_init);
3628
3629static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3630 struct ftrace_ops *op, struct pt_regs *pt_regs)
3631{
3632 struct ftrace_func_probe *entry;
3633 struct hlist_head *hhd;
3634 unsigned long key;
3635
3636 key = hash_long(ip, FTRACE_HASH_BITS);
3637
3638 hhd = &ftrace_func_hash[key];
3639
3640 if (hlist_empty(hhd))
3641 return;
3642
3643 /*
3644 * Disable preemption for these calls to prevent a RCU grace
3645 * period. This syncs the hash iteration and freeing of items
3646 * on the hash. rcu_read_lock is too dangerous here.
3647 */
3648 preempt_disable_notrace();
3649 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3650 if (entry->ip == ip)
3651 entry->ops->func(ip, parent_ip, &entry->data);
3652 }
3653 preempt_enable_notrace();
3654}
3655
3656static struct ftrace_ops trace_probe_ops __read_mostly =
3657{
3658 .func = function_trace_probe_call,
3659 .flags = FTRACE_OPS_FL_INITIALIZED,
3660 INIT_OPS_HASH(trace_probe_ops)
3661};
3662
3663static int ftrace_probe_registered;
3664
3665static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3666{
3667 int ret;
3668 int i;
3669
3670 if (ftrace_probe_registered) {
3671 /* still need to update the function call sites */
3672 if (ftrace_enabled)
3673 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3674 old_hash);
3675 return;
3676 }
3677
3678 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3679 struct hlist_head *hhd = &ftrace_func_hash[i];
3680 if (hhd->first)
3681 break;
3682 }
3683 /* Nothing registered? */
3684 if (i == FTRACE_FUNC_HASHSIZE)
3685 return;
3686
3687 ret = ftrace_startup(&trace_probe_ops, 0);
3688
3689 ftrace_probe_registered = 1;
3690}
3691
3692static void __disable_ftrace_function_probe(void)
3693{
3694 int i;
3695
3696 if (!ftrace_probe_registered)
3697 return;
3698
3699 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3700 struct hlist_head *hhd = &ftrace_func_hash[i];
3701 if (hhd->first)
3702 return;
3703 }
3704
3705 /* no more funcs left */
3706 ftrace_shutdown(&trace_probe_ops, 0);
3707
3708 ftrace_probe_registered = 0;
3709}
3710
3711
3712static void ftrace_free_entry(struct ftrace_func_probe *entry)
3713{
3714 if (entry->ops->free)
3715 entry->ops->free(entry->ops, entry->ip, &entry->data);
3716 kfree(entry);
3717}
3718
3719int
3720register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3721 void *data)
3722{
3723 struct ftrace_ops_hash old_hash_ops;
3724 struct ftrace_func_probe *entry;
3725 struct ftrace_glob func_g;
3726 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3727 struct ftrace_hash *old_hash = *orig_hash;
3728 struct ftrace_hash *hash;
3729 struct ftrace_page *pg;
3730 struct dyn_ftrace *rec;
3731 int not;
3732 unsigned long key;
3733 int count = 0;
3734 int ret;
3735
3736 func_g.type = filter_parse_regex(glob, strlen(glob),
3737 &func_g.search, ¬);
3738 func_g.len = strlen(func_g.search);
3739
3740 /* we do not support '!' for function probes */
3741 if (WARN_ON(not))
3742 return -EINVAL;
3743
3744 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3745
3746 old_hash_ops.filter_hash = old_hash;
3747 /* Probes only have filters */
3748 old_hash_ops.notrace_hash = NULL;
3749
3750 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3751 if (!hash) {
3752 count = -ENOMEM;
3753 goto out;
3754 }
3755
3756 if (unlikely(ftrace_disabled)) {
3757 count = -ENODEV;
3758 goto out;
3759 }
3760
3761 mutex_lock(&ftrace_lock);
3762
3763 do_for_each_ftrace_rec(pg, rec) {
3764
3765 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3766 continue;
3767
3768 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3769 if (!entry) {
3770 /* If we did not process any, then return error */
3771 if (!count)
3772 count = -ENOMEM;
3773 goto out_unlock;
3774 }
3775
3776 count++;
3777
3778 entry->data = data;
3779
3780 /*
3781 * The caller might want to do something special
3782 * for each function we find. We call the callback
3783 * to give the caller an opportunity to do so.
3784 */
3785 if (ops->init) {
3786 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3787 /* caller does not like this func */
3788 kfree(entry);
3789 continue;
3790 }
3791 }
3792
3793 ret = enter_record(hash, rec, 0);
3794 if (ret < 0) {
3795 kfree(entry);
3796 count = ret;
3797 goto out_unlock;
3798 }
3799
3800 entry->ops = ops;
3801 entry->ip = rec->ip;
3802
3803 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3804 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3805
3806 } while_for_each_ftrace_rec();
3807
3808 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3809
3810 __enable_ftrace_function_probe(&old_hash_ops);
3811
3812 if (!ret)
3813 free_ftrace_hash_rcu(old_hash);
3814 else
3815 count = ret;
3816
3817 out_unlock:
3818 mutex_unlock(&ftrace_lock);
3819 out:
3820 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3821 free_ftrace_hash(hash);
3822
3823 return count;
3824}
3825
3826enum {
3827 PROBE_TEST_FUNC = 1,
3828 PROBE_TEST_DATA = 2
3829};
3830
3831static void
3832__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3833 void *data, int flags)
3834{
3835 struct ftrace_func_entry *rec_entry;
3836 struct ftrace_func_probe *entry;
3837 struct ftrace_func_probe *p;
3838 struct ftrace_glob func_g;
3839 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3840 struct ftrace_hash *old_hash = *orig_hash;
3841 struct list_head free_list;
3842 struct ftrace_hash *hash;
3843 struct hlist_node *tmp;
3844 char str[KSYM_SYMBOL_LEN];
3845 int i, ret;
3846
3847 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3848 func_g.search = NULL;
3849 else if (glob) {
3850 int not;
3851
3852 func_g.type = filter_parse_regex(glob, strlen(glob),
3853 &func_g.search, ¬);
3854 func_g.len = strlen(func_g.search);
3855 func_g.search = glob;
3856
3857 /* we do not support '!' for function probes */
3858 if (WARN_ON(not))
3859 return;
3860 }
3861
3862 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3863
3864 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3865 if (!hash)
3866 /* Hmm, should report this somehow */
3867 goto out_unlock;
3868
3869 INIT_LIST_HEAD(&free_list);
3870
3871 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3872 struct hlist_head *hhd = &ftrace_func_hash[i];
3873
3874 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3875
3876 /* break up if statements for readability */
3877 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3878 continue;
3879
3880 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3881 continue;
3882
3883 /* do this last, since it is the most expensive */
3884 if (func_g.search) {
3885 kallsyms_lookup(entry->ip, NULL, NULL,
3886 NULL, str);
3887 if (!ftrace_match(str, &func_g))
3888 continue;
3889 }
3890
3891 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3892 /* It is possible more than one entry had this ip */
3893 if (rec_entry)
3894 free_hash_entry(hash, rec_entry);
3895
3896 hlist_del_rcu(&entry->node);
3897 list_add(&entry->free_list, &free_list);
3898 }
3899 }
3900 mutex_lock(&ftrace_lock);
3901 __disable_ftrace_function_probe();
3902 /*
3903 * Remove after the disable is called. Otherwise, if the last
3904 * probe is removed, a null hash means *all enabled*.
3905 */
3906 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3907 synchronize_sched();
3908 if (!ret)
3909 free_ftrace_hash_rcu(old_hash);
3910
3911 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3912 list_del(&entry->free_list);
3913 ftrace_free_entry(entry);
3914 }
3915 mutex_unlock(&ftrace_lock);
3916
3917 out_unlock:
3918 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3919 free_ftrace_hash(hash);
3920}
3921
3922void
3923unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3924 void *data)
3925{
3926 __unregister_ftrace_function_probe(glob, ops, data,
3927 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3928}
3929
3930void
3931unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3932{
3933 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3934}
3935
3936void unregister_ftrace_function_probe_all(char *glob)
3937{
3938 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3939}
3940
3941static LIST_HEAD(ftrace_commands);
3942static DEFINE_MUTEX(ftrace_cmd_mutex);
3943
3944/*
3945 * Currently we only register ftrace commands from __init, so mark this
3946 * __init too.
3947 */
3948__init int register_ftrace_command(struct ftrace_func_command *cmd)
3949{
3950 struct ftrace_func_command *p;
3951 int ret = 0;
3952
3953 mutex_lock(&ftrace_cmd_mutex);
3954 list_for_each_entry(p, &ftrace_commands, list) {
3955 if (strcmp(cmd->name, p->name) == 0) {
3956 ret = -EBUSY;
3957 goto out_unlock;
3958 }
3959 }
3960 list_add(&cmd->list, &ftrace_commands);
3961 out_unlock:
3962 mutex_unlock(&ftrace_cmd_mutex);
3963
3964 return ret;
3965}
3966
3967/*
3968 * Currently we only unregister ftrace commands from __init, so mark
3969 * this __init too.
3970 */
3971__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3972{
3973 struct ftrace_func_command *p, *n;
3974 int ret = -ENODEV;
3975
3976 mutex_lock(&ftrace_cmd_mutex);
3977 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3978 if (strcmp(cmd->name, p->name) == 0) {
3979 ret = 0;
3980 list_del_init(&p->list);
3981 goto out_unlock;
3982 }
3983 }
3984 out_unlock:
3985 mutex_unlock(&ftrace_cmd_mutex);
3986
3987 return ret;
3988}
3989
3990static int ftrace_process_regex(struct ftrace_hash *hash,
3991 char *buff, int len, int enable)
3992{
3993 char *func, *command, *next = buff;
3994 struct ftrace_func_command *p;
3995 int ret = -EINVAL;
3996
3997 func = strsep(&next, ":");
3998
3999 if (!next) {
4000 ret = ftrace_match_records(hash, func, len);
4001 if (!ret)
4002 ret = -EINVAL;
4003 if (ret < 0)
4004 return ret;
4005 return 0;
4006 }
4007
4008 /* command found */
4009
4010 command = strsep(&next, ":");
4011
4012 mutex_lock(&ftrace_cmd_mutex);
4013 list_for_each_entry(p, &ftrace_commands, list) {
4014 if (strcmp(p->name, command) == 0) {
4015 ret = p->func(hash, func, command, next, enable);
4016 goto out_unlock;
4017 }
4018 }
4019 out_unlock:
4020 mutex_unlock(&ftrace_cmd_mutex);
4021
4022 return ret;
4023}
4024
4025static ssize_t
4026ftrace_regex_write(struct file *file, const char __user *ubuf,
4027 size_t cnt, loff_t *ppos, int enable)
4028{
4029 struct ftrace_iterator *iter;
4030 struct trace_parser *parser;
4031 ssize_t ret, read;
4032
4033 if (!cnt)
4034 return 0;
4035
4036 if (file->f_mode & FMODE_READ) {
4037 struct seq_file *m = file->private_data;
4038 iter = m->private;
4039 } else
4040 iter = file->private_data;
4041
4042 if (unlikely(ftrace_disabled))
4043 return -ENODEV;
4044
4045 /* iter->hash is a local copy, so we don't need regex_lock */
4046
4047 parser = &iter->parser;
4048 read = trace_get_user(parser, ubuf, cnt, ppos);
4049
4050 if (read >= 0 && trace_parser_loaded(parser) &&
4051 !trace_parser_cont(parser)) {
4052 ret = ftrace_process_regex(iter->hash, parser->buffer,
4053 parser->idx, enable);
4054 trace_parser_clear(parser);
4055 if (ret < 0)
4056 goto out;
4057 }
4058
4059 ret = read;
4060 out:
4061 return ret;
4062}
4063
4064ssize_t
4065ftrace_filter_write(struct file *file, const char __user *ubuf,
4066 size_t cnt, loff_t *ppos)
4067{
4068 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4069}
4070
4071ssize_t
4072ftrace_notrace_write(struct file *file, const char __user *ubuf,
4073 size_t cnt, loff_t *ppos)
4074{
4075 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4076}
4077
4078static int
4079ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4080{
4081 struct ftrace_func_entry *entry;
4082
4083 if (!ftrace_location(ip))
4084 return -EINVAL;
4085
4086 if (remove) {
4087 entry = ftrace_lookup_ip(hash, ip);
4088 if (!entry)
4089 return -ENOENT;
4090 free_hash_entry(hash, entry);
4091 return 0;
4092 }
4093
4094 return add_hash_entry(hash, ip);
4095}
4096
4097static void ftrace_ops_update_code(struct ftrace_ops *ops,
4098 struct ftrace_ops_hash *old_hash)
4099{
4100 struct ftrace_ops *op;
4101
4102 if (!ftrace_enabled)
4103 return;
4104
4105 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4106 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4107 return;
4108 }
4109
4110 /*
4111 * If this is the shared global_ops filter, then we need to
4112 * check if there is another ops that shares it, is enabled.
4113 * If so, we still need to run the modify code.
4114 */
4115 if (ops->func_hash != &global_ops.local_hash)
4116 return;
4117
4118 do_for_each_ftrace_op(op, ftrace_ops_list) {
4119 if (op->func_hash == &global_ops.local_hash &&
4120 op->flags & FTRACE_OPS_FL_ENABLED) {
4121 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4122 /* Only need to do this once */
4123 return;
4124 }
4125 } while_for_each_ftrace_op(op);
4126}
4127
4128static int
4129ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4130 unsigned long ip, int remove, int reset, int enable)
4131{
4132 struct ftrace_hash **orig_hash;
4133 struct ftrace_ops_hash old_hash_ops;
4134 struct ftrace_hash *old_hash;
4135 struct ftrace_hash *hash;
4136 int ret;
4137
4138 if (unlikely(ftrace_disabled))
4139 return -ENODEV;
4140
4141 mutex_lock(&ops->func_hash->regex_lock);
4142
4143 if (enable)
4144 orig_hash = &ops->func_hash->filter_hash;
4145 else
4146 orig_hash = &ops->func_hash->notrace_hash;
4147
4148 if (reset)
4149 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4150 else
4151 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4152
4153 if (!hash) {
4154 ret = -ENOMEM;
4155 goto out_regex_unlock;
4156 }
4157
4158 if (buf && !ftrace_match_records(hash, buf, len)) {
4159 ret = -EINVAL;
4160 goto out_regex_unlock;
4161 }
4162 if (ip) {
4163 ret = ftrace_match_addr(hash, ip, remove);
4164 if (ret < 0)
4165 goto out_regex_unlock;
4166 }
4167
4168 mutex_lock(&ftrace_lock);
4169 old_hash = *orig_hash;
4170 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4171 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4172 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4173 if (!ret) {
4174 ftrace_ops_update_code(ops, &old_hash_ops);
4175 free_ftrace_hash_rcu(old_hash);
4176 }
4177 mutex_unlock(&ftrace_lock);
4178
4179 out_regex_unlock:
4180 mutex_unlock(&ops->func_hash->regex_lock);
4181
4182 free_ftrace_hash(hash);
4183 return ret;
4184}
4185
4186static int
4187ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4188 int reset, int enable)
4189{
4190 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4191}
4192
4193/**
4194 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4195 * @ops - the ops to set the filter with
4196 * @ip - the address to add to or remove from the filter.
4197 * @remove - non zero to remove the ip from the filter
4198 * @reset - non zero to reset all filters before applying this filter.
4199 *
4200 * Filters denote which functions should be enabled when tracing is enabled
4201 * If @ip is NULL, it failes to update filter.
4202 */
4203int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4204 int remove, int reset)
4205{
4206 ftrace_ops_init(ops);
4207 return ftrace_set_addr(ops, ip, remove, reset, 1);
4208}
4209EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4210
4211static int
4212ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4213 int reset, int enable)
4214{
4215 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4216}
4217
4218/**
4219 * ftrace_set_filter - set a function to filter on in ftrace
4220 * @ops - the ops to set the filter with
4221 * @buf - the string that holds the function filter text.
4222 * @len - the length of the string.
4223 * @reset - non zero to reset all filters before applying this filter.
4224 *
4225 * Filters denote which functions should be enabled when tracing is enabled.
4226 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4227 */
4228int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4229 int len, int reset)
4230{
4231 ftrace_ops_init(ops);
4232 return ftrace_set_regex(ops, buf, len, reset, 1);
4233}
4234EXPORT_SYMBOL_GPL(ftrace_set_filter);
4235
4236/**
4237 * ftrace_set_notrace - set a function to not trace in ftrace
4238 * @ops - the ops to set the notrace filter with
4239 * @buf - the string that holds the function notrace text.
4240 * @len - the length of the string.
4241 * @reset - non zero to reset all filters before applying this filter.
4242 *
4243 * Notrace Filters denote which functions should not be enabled when tracing
4244 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4245 * for tracing.
4246 */
4247int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4248 int len, int reset)
4249{
4250 ftrace_ops_init(ops);
4251 return ftrace_set_regex(ops, buf, len, reset, 0);
4252}
4253EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4254/**
4255 * ftrace_set_global_filter - set a function to filter on with global tracers
4256 * @buf - the string that holds the function filter text.
4257 * @len - the length of the string.
4258 * @reset - non zero to reset all filters before applying this filter.
4259 *
4260 * Filters denote which functions should be enabled when tracing is enabled.
4261 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4262 */
4263void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4264{
4265 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4266}
4267EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4268
4269/**
4270 * ftrace_set_global_notrace - set a function to not trace with global tracers
4271 * @buf - the string that holds the function notrace text.
4272 * @len - the length of the string.
4273 * @reset - non zero to reset all filters before applying this filter.
4274 *
4275 * Notrace Filters denote which functions should not be enabled when tracing
4276 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4277 * for tracing.
4278 */
4279void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4280{
4281 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4282}
4283EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4284
4285/*
4286 * command line interface to allow users to set filters on boot up.
4287 */
4288#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4289static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4290static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4291
4292/* Used by function selftest to not test if filter is set */
4293bool ftrace_filter_param __initdata;
4294
4295static int __init set_ftrace_notrace(char *str)
4296{
4297 ftrace_filter_param = true;
4298 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4299 return 1;
4300}
4301__setup("ftrace_notrace=", set_ftrace_notrace);
4302
4303static int __init set_ftrace_filter(char *str)
4304{
4305 ftrace_filter_param = true;
4306 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4307 return 1;
4308}
4309__setup("ftrace_filter=", set_ftrace_filter);
4310
4311#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4312static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4313static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4314static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4315
4316static unsigned long save_global_trampoline;
4317static unsigned long save_global_flags;
4318
4319static int __init set_graph_function(char *str)
4320{
4321 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4322 return 1;
4323}
4324__setup("ftrace_graph_filter=", set_graph_function);
4325
4326static int __init set_graph_notrace_function(char *str)
4327{
4328 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4329 return 1;
4330}
4331__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4332
4333static void __init set_ftrace_early_graph(char *buf, int enable)
4334{
4335 int ret;
4336 char *func;
4337 unsigned long *table = ftrace_graph_funcs;
4338 int *count = &ftrace_graph_count;
4339
4340 if (!enable) {
4341 table = ftrace_graph_notrace_funcs;
4342 count = &ftrace_graph_notrace_count;
4343 }
4344
4345 while (buf) {
4346 func = strsep(&buf, ",");
4347 /* we allow only one expression at a time */
4348 ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4349 if (ret)
4350 printk(KERN_DEBUG "ftrace: function %s not "
4351 "traceable\n", func);
4352 }
4353}
4354#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4355
4356void __init
4357ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4358{
4359 char *func;
4360
4361 ftrace_ops_init(ops);
4362
4363 while (buf) {
4364 func = strsep(&buf, ",");
4365 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4366 }
4367}
4368
4369static void __init set_ftrace_early_filters(void)
4370{
4371 if (ftrace_filter_buf[0])
4372 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4373 if (ftrace_notrace_buf[0])
4374 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4375#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4376 if (ftrace_graph_buf[0])
4377 set_ftrace_early_graph(ftrace_graph_buf, 1);
4378 if (ftrace_graph_notrace_buf[0])
4379 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4380#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4381}
4382
4383int ftrace_regex_release(struct inode *inode, struct file *file)
4384{
4385 struct seq_file *m = (struct seq_file *)file->private_data;
4386 struct ftrace_ops_hash old_hash_ops;
4387 struct ftrace_iterator *iter;
4388 struct ftrace_hash **orig_hash;
4389 struct ftrace_hash *old_hash;
4390 struct trace_parser *parser;
4391 int filter_hash;
4392 int ret;
4393
4394 if (file->f_mode & FMODE_READ) {
4395 iter = m->private;
4396 seq_release(inode, file);
4397 } else
4398 iter = file->private_data;
4399
4400 parser = &iter->parser;
4401 if (trace_parser_loaded(parser)) {
4402 parser->buffer[parser->idx] = 0;
4403 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4404 }
4405
4406 trace_parser_put(parser);
4407
4408 mutex_lock(&iter->ops->func_hash->regex_lock);
4409
4410 if (file->f_mode & FMODE_WRITE) {
4411 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4412
4413 if (filter_hash)
4414 orig_hash = &iter->ops->func_hash->filter_hash;
4415 else
4416 orig_hash = &iter->ops->func_hash->notrace_hash;
4417
4418 mutex_lock(&ftrace_lock);
4419 old_hash = *orig_hash;
4420 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4421 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4422 ret = ftrace_hash_move(iter->ops, filter_hash,
4423 orig_hash, iter->hash);
4424 if (!ret) {
4425 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4426 free_ftrace_hash_rcu(old_hash);
4427 }
4428 mutex_unlock(&ftrace_lock);
4429 }
4430
4431 mutex_unlock(&iter->ops->func_hash->regex_lock);
4432 free_ftrace_hash(iter->hash);
4433 kfree(iter);
4434
4435 return 0;
4436}
4437
4438static const struct file_operations ftrace_avail_fops = {
4439 .open = ftrace_avail_open,
4440 .read = seq_read,
4441 .llseek = seq_lseek,
4442 .release = seq_release_private,
4443};
4444
4445static const struct file_operations ftrace_enabled_fops = {
4446 .open = ftrace_enabled_open,
4447 .read = seq_read,
4448 .llseek = seq_lseek,
4449 .release = seq_release_private,
4450};
4451
4452static const struct file_operations ftrace_filter_fops = {
4453 .open = ftrace_filter_open,
4454 .read = seq_read,
4455 .write = ftrace_filter_write,
4456 .llseek = tracing_lseek,
4457 .release = ftrace_regex_release,
4458};
4459
4460static const struct file_operations ftrace_notrace_fops = {
4461 .open = ftrace_notrace_open,
4462 .read = seq_read,
4463 .write = ftrace_notrace_write,
4464 .llseek = tracing_lseek,
4465 .release = ftrace_regex_release,
4466};
4467
4468#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4469
4470static DEFINE_MUTEX(graph_lock);
4471
4472int ftrace_graph_count;
4473int ftrace_graph_notrace_count;
4474unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4475unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4476
4477struct ftrace_graph_data {
4478 unsigned long *table;
4479 size_t size;
4480 int *count;
4481 const struct seq_operations *seq_ops;
4482};
4483
4484static void *
4485__g_next(struct seq_file *m, loff_t *pos)
4486{
4487 struct ftrace_graph_data *fgd = m->private;
4488
4489 if (*pos >= *fgd->count)
4490 return NULL;
4491 return &fgd->table[*pos];
4492}
4493
4494static void *
4495g_next(struct seq_file *m, void *v, loff_t *pos)
4496{
4497 (*pos)++;
4498 return __g_next(m, pos);
4499}
4500
4501static void *g_start(struct seq_file *m, loff_t *pos)
4502{
4503 struct ftrace_graph_data *fgd = m->private;
4504
4505 mutex_lock(&graph_lock);
4506
4507 /* Nothing, tell g_show to print all functions are enabled */
4508 if (!*fgd->count && !*pos)
4509 return (void *)1;
4510
4511 return __g_next(m, pos);
4512}
4513
4514static void g_stop(struct seq_file *m, void *p)
4515{
4516 mutex_unlock(&graph_lock);
4517}
4518
4519static int g_show(struct seq_file *m, void *v)
4520{
4521 unsigned long *ptr = v;
4522
4523 if (!ptr)
4524 return 0;
4525
4526 if (ptr == (unsigned long *)1) {
4527 struct ftrace_graph_data *fgd = m->private;
4528
4529 if (fgd->table == ftrace_graph_funcs)
4530 seq_puts(m, "#### all functions enabled ####\n");
4531 else
4532 seq_puts(m, "#### no functions disabled ####\n");
4533 return 0;
4534 }
4535
4536 seq_printf(m, "%ps\n", (void *)*ptr);
4537
4538 return 0;
4539}
4540
4541static const struct seq_operations ftrace_graph_seq_ops = {
4542 .start = g_start,
4543 .next = g_next,
4544 .stop = g_stop,
4545 .show = g_show,
4546};
4547
4548static int
4549__ftrace_graph_open(struct inode *inode, struct file *file,
4550 struct ftrace_graph_data *fgd)
4551{
4552 int ret = 0;
4553
4554 mutex_lock(&graph_lock);
4555 if ((file->f_mode & FMODE_WRITE) &&
4556 (file->f_flags & O_TRUNC)) {
4557 *fgd->count = 0;
4558 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4559 }
4560 mutex_unlock(&graph_lock);
4561
4562 if (file->f_mode & FMODE_READ) {
4563 ret = seq_open(file, fgd->seq_ops);
4564 if (!ret) {
4565 struct seq_file *m = file->private_data;
4566 m->private = fgd;
4567 }
4568 } else
4569 file->private_data = fgd;
4570
4571 return ret;
4572}
4573
4574static int
4575ftrace_graph_open(struct inode *inode, struct file *file)
4576{
4577 struct ftrace_graph_data *fgd;
4578
4579 if (unlikely(ftrace_disabled))
4580 return -ENODEV;
4581
4582 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4583 if (fgd == NULL)
4584 return -ENOMEM;
4585
4586 fgd->table = ftrace_graph_funcs;
4587 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4588 fgd->count = &ftrace_graph_count;
4589 fgd->seq_ops = &ftrace_graph_seq_ops;
4590
4591 return __ftrace_graph_open(inode, file, fgd);
4592}
4593
4594static int
4595ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4596{
4597 struct ftrace_graph_data *fgd;
4598
4599 if (unlikely(ftrace_disabled))
4600 return -ENODEV;
4601
4602 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4603 if (fgd == NULL)
4604 return -ENOMEM;
4605
4606 fgd->table = ftrace_graph_notrace_funcs;
4607 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4608 fgd->count = &ftrace_graph_notrace_count;
4609 fgd->seq_ops = &ftrace_graph_seq_ops;
4610
4611 return __ftrace_graph_open(inode, file, fgd);
4612}
4613
4614static int
4615ftrace_graph_release(struct inode *inode, struct file *file)
4616{
4617 if (file->f_mode & FMODE_READ) {
4618 struct seq_file *m = file->private_data;
4619
4620 kfree(m->private);
4621 seq_release(inode, file);
4622 } else {
4623 kfree(file->private_data);
4624 }
4625
4626 return 0;
4627}
4628
4629static int
4630ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4631{
4632 struct ftrace_glob func_g;
4633 struct dyn_ftrace *rec;
4634 struct ftrace_page *pg;
4635 int fail = 1;
4636 int not;
4637 bool exists;
4638 int i;
4639
4640 /* decode regex */
4641 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4642 &func_g.search, ¬);
4643 if (!not && *idx >= size)
4644 return -EBUSY;
4645
4646 func_g.len = strlen(func_g.search);
4647
4648 mutex_lock(&ftrace_lock);
4649
4650 if (unlikely(ftrace_disabled)) {
4651 mutex_unlock(&ftrace_lock);
4652 return -ENODEV;
4653 }
4654
4655 do_for_each_ftrace_rec(pg, rec) {
4656
4657 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4658 /* if it is in the array */
4659 exists = false;
4660 for (i = 0; i < *idx; i++) {
4661 if (array[i] == rec->ip) {
4662 exists = true;
4663 break;
4664 }
4665 }
4666
4667 if (!not) {
4668 fail = 0;
4669 if (!exists) {
4670 array[(*idx)++] = rec->ip;
4671 if (*idx >= size)
4672 goto out;
4673 }
4674 } else {
4675 if (exists) {
4676 array[i] = array[--(*idx)];
4677 array[*idx] = 0;
4678 fail = 0;
4679 }
4680 }
4681 }
4682 } while_for_each_ftrace_rec();
4683out:
4684 mutex_unlock(&ftrace_lock);
4685
4686 if (fail)
4687 return -EINVAL;
4688
4689 return 0;
4690}
4691
4692static ssize_t
4693ftrace_graph_write(struct file *file, const char __user *ubuf,
4694 size_t cnt, loff_t *ppos)
4695{
4696 struct trace_parser parser;
4697 ssize_t read, ret = 0;
4698 struct ftrace_graph_data *fgd = file->private_data;
4699
4700 if (!cnt)
4701 return 0;
4702
4703 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4704 return -ENOMEM;
4705
4706 read = trace_get_user(&parser, ubuf, cnt, ppos);
4707
4708 if (read >= 0 && trace_parser_loaded((&parser))) {
4709 parser.buffer[parser.idx] = 0;
4710
4711 mutex_lock(&graph_lock);
4712
4713 /* we allow only one expression at a time */
4714 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4715 parser.buffer);
4716
4717 mutex_unlock(&graph_lock);
4718 }
4719
4720 if (!ret)
4721 ret = read;
4722
4723 trace_parser_put(&parser);
4724
4725 return ret;
4726}
4727
4728static const struct file_operations ftrace_graph_fops = {
4729 .open = ftrace_graph_open,
4730 .read = seq_read,
4731 .write = ftrace_graph_write,
4732 .llseek = tracing_lseek,
4733 .release = ftrace_graph_release,
4734};
4735
4736static const struct file_operations ftrace_graph_notrace_fops = {
4737 .open = ftrace_graph_notrace_open,
4738 .read = seq_read,
4739 .write = ftrace_graph_write,
4740 .llseek = tracing_lseek,
4741 .release = ftrace_graph_release,
4742};
4743#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4744
4745void ftrace_create_filter_files(struct ftrace_ops *ops,
4746 struct dentry *parent)
4747{
4748
4749 trace_create_file("set_ftrace_filter", 0644, parent,
4750 ops, &ftrace_filter_fops);
4751
4752 trace_create_file("set_ftrace_notrace", 0644, parent,
4753 ops, &ftrace_notrace_fops);
4754}
4755
4756/*
4757 * The name "destroy_filter_files" is really a misnomer. Although
4758 * in the future, it may actualy delete the files, but this is
4759 * really intended to make sure the ops passed in are disabled
4760 * and that when this function returns, the caller is free to
4761 * free the ops.
4762 *
4763 * The "destroy" name is only to match the "create" name that this
4764 * should be paired with.
4765 */
4766void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4767{
4768 mutex_lock(&ftrace_lock);
4769 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4770 ftrace_shutdown(ops, 0);
4771 ops->flags |= FTRACE_OPS_FL_DELETED;
4772 mutex_unlock(&ftrace_lock);
4773}
4774
4775static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4776{
4777
4778 trace_create_file("available_filter_functions", 0444,
4779 d_tracer, NULL, &ftrace_avail_fops);
4780
4781 trace_create_file("enabled_functions", 0444,
4782 d_tracer, NULL, &ftrace_enabled_fops);
4783
4784 ftrace_create_filter_files(&global_ops, d_tracer);
4785
4786#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4787 trace_create_file("set_graph_function", 0444, d_tracer,
4788 NULL,
4789 &ftrace_graph_fops);
4790 trace_create_file("set_graph_notrace", 0444, d_tracer,
4791 NULL,
4792 &ftrace_graph_notrace_fops);
4793#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4794
4795 return 0;
4796}
4797
4798static int ftrace_cmp_ips(const void *a, const void *b)
4799{
4800 const unsigned long *ipa = a;
4801 const unsigned long *ipb = b;
4802
4803 if (*ipa > *ipb)
4804 return 1;
4805 if (*ipa < *ipb)
4806 return -1;
4807 return 0;
4808}
4809
4810static int ftrace_process_locs(struct module *mod,
4811 unsigned long *start,
4812 unsigned long *end)
4813{
4814 struct ftrace_page *start_pg;
4815 struct ftrace_page *pg;
4816 struct dyn_ftrace *rec;
4817 unsigned long count;
4818 unsigned long *p;
4819 unsigned long addr;
4820 unsigned long flags = 0; /* Shut up gcc */
4821 int ret = -ENOMEM;
4822
4823 count = end - start;
4824
4825 if (!count)
4826 return 0;
4827
4828 sort(start, count, sizeof(*start),
4829 ftrace_cmp_ips, NULL);
4830
4831 start_pg = ftrace_allocate_pages(count);
4832 if (!start_pg)
4833 return -ENOMEM;
4834
4835 mutex_lock(&ftrace_lock);
4836
4837 /*
4838 * Core and each module needs their own pages, as
4839 * modules will free them when they are removed.
4840 * Force a new page to be allocated for modules.
4841 */
4842 if (!mod) {
4843 WARN_ON(ftrace_pages || ftrace_pages_start);
4844 /* First initialization */
4845 ftrace_pages = ftrace_pages_start = start_pg;
4846 } else {
4847 if (!ftrace_pages)
4848 goto out;
4849
4850 if (WARN_ON(ftrace_pages->next)) {
4851 /* Hmm, we have free pages? */
4852 while (ftrace_pages->next)
4853 ftrace_pages = ftrace_pages->next;
4854 }
4855
4856 ftrace_pages->next = start_pg;
4857 }
4858
4859 p = start;
4860 pg = start_pg;
4861 while (p < end) {
4862 addr = ftrace_call_adjust(*p++);
4863 /*
4864 * Some architecture linkers will pad between
4865 * the different mcount_loc sections of different
4866 * object files to satisfy alignments.
4867 * Skip any NULL pointers.
4868 */
4869 if (!addr)
4870 continue;
4871
4872 if (pg->index == pg->size) {
4873 /* We should have allocated enough */
4874 if (WARN_ON(!pg->next))
4875 break;
4876 pg = pg->next;
4877 }
4878
4879 rec = &pg->records[pg->index++];
4880 rec->ip = addr;
4881 }
4882
4883 /* We should have used all pages */
4884 WARN_ON(pg->next);
4885
4886 /* Assign the last page to ftrace_pages */
4887 ftrace_pages = pg;
4888
4889 /*
4890 * We only need to disable interrupts on start up
4891 * because we are modifying code that an interrupt
4892 * may execute, and the modification is not atomic.
4893 * But for modules, nothing runs the code we modify
4894 * until we are finished with it, and there's no
4895 * reason to cause large interrupt latencies while we do it.
4896 */
4897 if (!mod)
4898 local_irq_save(flags);
4899 ftrace_update_code(mod, start_pg);
4900 if (!mod)
4901 local_irq_restore(flags);
4902 ret = 0;
4903 out:
4904 mutex_unlock(&ftrace_lock);
4905
4906 return ret;
4907}
4908
4909#ifdef CONFIG_MODULES
4910
4911#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4912
4913static int referenced_filters(struct dyn_ftrace *rec)
4914{
4915 struct ftrace_ops *ops;
4916 int cnt = 0;
4917
4918 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
4919 if (ops_references_rec(ops, rec))
4920 cnt++;
4921 }
4922
4923 return cnt;
4924}
4925
4926void ftrace_release_mod(struct module *mod)
4927{
4928 struct dyn_ftrace *rec;
4929 struct ftrace_page **last_pg;
4930 struct ftrace_page *pg;
4931 int order;
4932
4933 mutex_lock(&ftrace_lock);
4934
4935 if (ftrace_disabled)
4936 goto out_unlock;
4937
4938 /*
4939 * Each module has its own ftrace_pages, remove
4940 * them from the list.
4941 */
4942 last_pg = &ftrace_pages_start;
4943 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4944 rec = &pg->records[0];
4945 if (within_module_core(rec->ip, mod)) {
4946 /*
4947 * As core pages are first, the first
4948 * page should never be a module page.
4949 */
4950 if (WARN_ON(pg == ftrace_pages_start))
4951 goto out_unlock;
4952
4953 /* Check if we are deleting the last page */
4954 if (pg == ftrace_pages)
4955 ftrace_pages = next_to_ftrace_page(last_pg);
4956
4957 *last_pg = pg->next;
4958 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4959 free_pages((unsigned long)pg->records, order);
4960 kfree(pg);
4961 } else
4962 last_pg = &pg->next;
4963 }
4964 out_unlock:
4965 mutex_unlock(&ftrace_lock);
4966}
4967
4968void ftrace_module_enable(struct module *mod)
4969{
4970 struct dyn_ftrace *rec;
4971 struct ftrace_page *pg;
4972
4973 mutex_lock(&ftrace_lock);
4974
4975 if (ftrace_disabled)
4976 goto out_unlock;
4977
4978 /*
4979 * If the tracing is enabled, go ahead and enable the record.
4980 *
4981 * The reason not to enable the record immediatelly is the
4982 * inherent check of ftrace_make_nop/ftrace_make_call for
4983 * correct previous instructions. Making first the NOP
4984 * conversion puts the module to the correct state, thus
4985 * passing the ftrace_make_call check.
4986 *
4987 * We also delay this to after the module code already set the
4988 * text to read-only, as we now need to set it back to read-write
4989 * so that we can modify the text.
4990 */
4991 if (ftrace_start_up)
4992 ftrace_arch_code_modify_prepare();
4993
4994 do_for_each_ftrace_rec(pg, rec) {
4995 int cnt;
4996 /*
4997 * do_for_each_ftrace_rec() is a double loop.
4998 * module text shares the pg. If a record is
4999 * not part of this module, then skip this pg,
5000 * which the "break" will do.
5001 */
5002 if (!within_module_core(rec->ip, mod))
5003 break;
5004
5005 cnt = 0;
5006
5007 /*
5008 * When adding a module, we need to check if tracers are
5009 * currently enabled and if they are, and can trace this record,
5010 * we need to enable the module functions as well as update the
5011 * reference counts for those function records.
5012 */
5013 if (ftrace_start_up)
5014 cnt += referenced_filters(rec);
5015
5016 /* This clears FTRACE_FL_DISABLED */
5017 rec->flags = cnt;
5018
5019 if (ftrace_start_up && cnt) {
5020 int failed = __ftrace_replace_code(rec, 1);
5021 if (failed) {
5022 ftrace_bug(failed, rec);
5023 goto out_loop;
5024 }
5025 }
5026
5027 } while_for_each_ftrace_rec();
5028
5029 out_loop:
5030 if (ftrace_start_up)
5031 ftrace_arch_code_modify_post_process();
5032
5033 out_unlock:
5034 mutex_unlock(&ftrace_lock);
5035}
5036
5037void ftrace_module_init(struct module *mod)
5038{
5039 if (ftrace_disabled || !mod->num_ftrace_callsites)
5040 return;
5041
5042 ftrace_process_locs(mod, mod->ftrace_callsites,
5043 mod->ftrace_callsites + mod->num_ftrace_callsites);
5044}
5045#endif /* CONFIG_MODULES */
5046
5047void __init ftrace_init(void)
5048{
5049 extern unsigned long __start_mcount_loc[];
5050 extern unsigned long __stop_mcount_loc[];
5051 unsigned long count, flags;
5052 int ret;
5053
5054 local_irq_save(flags);
5055 ret = ftrace_dyn_arch_init();
5056 local_irq_restore(flags);
5057 if (ret)
5058 goto failed;
5059
5060 count = __stop_mcount_loc - __start_mcount_loc;
5061 if (!count) {
5062 pr_info("ftrace: No functions to be traced?\n");
5063 goto failed;
5064 }
5065
5066 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5067 count, count / ENTRIES_PER_PAGE + 1);
5068
5069 last_ftrace_enabled = ftrace_enabled = 1;
5070
5071 ret = ftrace_process_locs(NULL,
5072 __start_mcount_loc,
5073 __stop_mcount_loc);
5074
5075 set_ftrace_early_filters();
5076
5077 return;
5078 failed:
5079 ftrace_disabled = 1;
5080}
5081
5082/* Do nothing if arch does not support this */
5083void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5084{
5085}
5086
5087static void ftrace_update_trampoline(struct ftrace_ops *ops)
5088{
5089
5090/*
5091 * Currently there's no safe way to free a trampoline when the kernel
5092 * is configured with PREEMPT. That is because a task could be preempted
5093 * when it jumped to the trampoline, it may be preempted for a long time
5094 * depending on the system load, and currently there's no way to know
5095 * when it will be off the trampoline. If the trampoline is freed
5096 * too early, when the task runs again, it will be executing on freed
5097 * memory and crash.
5098 */
5099#ifdef CONFIG_PREEMPT
5100 /* Currently, only non dynamic ops can have a trampoline */
5101 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5102 return;
5103#endif
5104
5105 arch_ftrace_update_trampoline(ops);
5106}
5107
5108#else
5109
5110static struct ftrace_ops global_ops = {
5111 .func = ftrace_stub,
5112 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5113 FTRACE_OPS_FL_INITIALIZED |
5114 FTRACE_OPS_FL_PID,
5115};
5116
5117static int __init ftrace_nodyn_init(void)
5118{
5119 ftrace_enabled = 1;
5120 return 0;
5121}
5122core_initcall(ftrace_nodyn_init);
5123
5124static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5125static inline void ftrace_startup_enable(int command) { }
5126static inline void ftrace_startup_all(int command) { }
5127/* Keep as macros so we do not need to define the commands */
5128# define ftrace_startup(ops, command) \
5129 ({ \
5130 int ___ret = __register_ftrace_function(ops); \
5131 if (!___ret) \
5132 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5133 ___ret; \
5134 })
5135# define ftrace_shutdown(ops, command) \
5136 ({ \
5137 int ___ret = __unregister_ftrace_function(ops); \
5138 if (!___ret) \
5139 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5140 ___ret; \
5141 })
5142
5143# define ftrace_startup_sysctl() do { } while (0)
5144# define ftrace_shutdown_sysctl() do { } while (0)
5145
5146static inline int
5147ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5148{
5149 return 1;
5150}
5151
5152static void ftrace_update_trampoline(struct ftrace_ops *ops)
5153{
5154}
5155
5156#endif /* CONFIG_DYNAMIC_FTRACE */
5157
5158__init void ftrace_init_global_array_ops(struct trace_array *tr)
5159{
5160 tr->ops = &global_ops;
5161 tr->ops->private = tr;
5162}
5163
5164void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5165{
5166 /* If we filter on pids, update to use the pid function */
5167 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5168 if (WARN_ON(tr->ops->func != ftrace_stub))
5169 printk("ftrace ops had %pS for function\n",
5170 tr->ops->func);
5171 }
5172 tr->ops->func = func;
5173 tr->ops->private = tr;
5174}
5175
5176void ftrace_reset_array_ops(struct trace_array *tr)
5177{
5178 tr->ops->func = ftrace_stub;
5179}
5180
5181static inline void
5182__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5183 struct ftrace_ops *ignored, struct pt_regs *regs)
5184{
5185 struct ftrace_ops *op;
5186 int bit;
5187
5188 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5189 if (bit < 0)
5190 return;
5191
5192 /*
5193 * Some of the ops may be dynamically allocated,
5194 * they must be freed after a synchronize_sched().
5195 */
5196 preempt_disable_notrace();
5197
5198 do_for_each_ftrace_op(op, ftrace_ops_list) {
5199 /*
5200 * Check the following for each ops before calling their func:
5201 * if RCU flag is set, then rcu_is_watching() must be true
5202 * if PER_CPU is set, then ftrace_function_local_disable()
5203 * must be false
5204 * Otherwise test if the ip matches the ops filter
5205 *
5206 * If any of the above fails then the op->func() is not executed.
5207 */
5208 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5209 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5210 !ftrace_function_local_disabled(op)) &&
5211 ftrace_ops_test(op, ip, regs)) {
5212
5213 if (FTRACE_WARN_ON(!op->func)) {
5214 pr_warn("op=%p %pS\n", op, op);
5215 goto out;
5216 }
5217 op->func(ip, parent_ip, op, regs);
5218 }
5219 } while_for_each_ftrace_op(op);
5220out:
5221 preempt_enable_notrace();
5222 trace_clear_recursion(bit);
5223}
5224
5225/*
5226 * Some archs only support passing ip and parent_ip. Even though
5227 * the list function ignores the op parameter, we do not want any
5228 * C side effects, where a function is called without the caller
5229 * sending a third parameter.
5230 * Archs are to support both the regs and ftrace_ops at the same time.
5231 * If they support ftrace_ops, it is assumed they support regs.
5232 * If call backs want to use regs, they must either check for regs
5233 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5234 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5235 * An architecture can pass partial regs with ftrace_ops and still
5236 * set the ARCH_SUPPORTS_FTRACE_OPS.
5237 */
5238#if ARCH_SUPPORTS_FTRACE_OPS
5239static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5240 struct ftrace_ops *op, struct pt_regs *regs)
5241{
5242 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5243}
5244#else
5245static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5246{
5247 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5248}
5249#endif
5250
5251/*
5252 * If there's only one function registered but it does not support
5253 * recursion, needs RCU protection and/or requires per cpu handling, then
5254 * this function will be called by the mcount trampoline.
5255 */
5256static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
5257 struct ftrace_ops *op, struct pt_regs *regs)
5258{
5259 int bit;
5260
5261 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
5262 return;
5263
5264 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5265 if (bit < 0)
5266 return;
5267
5268 preempt_disable_notrace();
5269
5270 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5271 !ftrace_function_local_disabled(op)) {
5272 op->func(ip, parent_ip, op, regs);
5273 }
5274
5275 preempt_enable_notrace();
5276 trace_clear_recursion(bit);
5277}
5278
5279/**
5280 * ftrace_ops_get_func - get the function a trampoline should call
5281 * @ops: the ops to get the function for
5282 *
5283 * Normally the mcount trampoline will call the ops->func, but there
5284 * are times that it should not. For example, if the ops does not
5285 * have its own recursion protection, then it should call the
5286 * ftrace_ops_recurs_func() instead.
5287 *
5288 * Returns the function that the trampoline should call for @ops.
5289 */
5290ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5291{
5292 /*
5293 * If the function does not handle recursion, needs to be RCU safe,
5294 * or does per cpu logic, then we need to call the assist handler.
5295 */
5296 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
5297 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
5298 return ftrace_ops_assist_func;
5299
5300 return ops->func;
5301}
5302
5303static void clear_ftrace_swapper(void)
5304{
5305 struct task_struct *p;
5306 int cpu;
5307
5308 get_online_cpus();
5309 for_each_online_cpu(cpu) {
5310 p = idle_task(cpu);
5311 clear_tsk_trace_trace(p);
5312 }
5313 put_online_cpus();
5314}
5315
5316static void set_ftrace_swapper(void)
5317{
5318 struct task_struct *p;
5319 int cpu;
5320
5321 get_online_cpus();
5322 for_each_online_cpu(cpu) {
5323 p = idle_task(cpu);
5324 set_tsk_trace_trace(p);
5325 }
5326 put_online_cpus();
5327}
5328
5329static void clear_ftrace_pid(struct pid *pid)
5330{
5331 struct task_struct *p;
5332
5333 rcu_read_lock();
5334 do_each_pid_task(pid, PIDTYPE_PID, p) {
5335 clear_tsk_trace_trace(p);
5336 } while_each_pid_task(pid, PIDTYPE_PID, p);
5337 rcu_read_unlock();
5338
5339 put_pid(pid);
5340}
5341
5342static void set_ftrace_pid(struct pid *pid)
5343{
5344 struct task_struct *p;
5345
5346 rcu_read_lock();
5347 do_each_pid_task(pid, PIDTYPE_PID, p) {
5348 set_tsk_trace_trace(p);
5349 } while_each_pid_task(pid, PIDTYPE_PID, p);
5350 rcu_read_unlock();
5351}
5352
5353static void clear_ftrace_pid_task(struct pid *pid)
5354{
5355 if (pid == ftrace_swapper_pid)
5356 clear_ftrace_swapper();
5357 else
5358 clear_ftrace_pid(pid);
5359}
5360
5361static void set_ftrace_pid_task(struct pid *pid)
5362{
5363 if (pid == ftrace_swapper_pid)
5364 set_ftrace_swapper();
5365 else
5366 set_ftrace_pid(pid);
5367}
5368
5369static int ftrace_pid_add(int p)
5370{
5371 struct pid *pid;
5372 struct ftrace_pid *fpid;
5373 int ret = -EINVAL;
5374
5375 mutex_lock(&ftrace_lock);
5376
5377 if (!p)
5378 pid = ftrace_swapper_pid;
5379 else
5380 pid = find_get_pid(p);
5381
5382 if (!pid)
5383 goto out;
5384
5385 ret = 0;
5386
5387 list_for_each_entry(fpid, &ftrace_pids, list)
5388 if (fpid->pid == pid)
5389 goto out_put;
5390
5391 ret = -ENOMEM;
5392
5393 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
5394 if (!fpid)
5395 goto out_put;
5396
5397 list_add(&fpid->list, &ftrace_pids);
5398 fpid->pid = pid;
5399
5400 set_ftrace_pid_task(pid);
5401
5402 ftrace_update_pid_func();
5403
5404 ftrace_startup_all(0);
5405
5406 mutex_unlock(&ftrace_lock);
5407 return 0;
5408
5409out_put:
5410 if (pid != ftrace_swapper_pid)
5411 put_pid(pid);
5412
5413out:
5414 mutex_unlock(&ftrace_lock);
5415 return ret;
5416}
5417
5418static void ftrace_pid_reset(void)
5419{
5420 struct ftrace_pid *fpid, *safe;
5421
5422 mutex_lock(&ftrace_lock);
5423 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
5424 struct pid *pid = fpid->pid;
5425
5426 clear_ftrace_pid_task(pid);
5427
5428 list_del(&fpid->list);
5429 kfree(fpid);
5430 }
5431
5432 ftrace_update_pid_func();
5433 ftrace_startup_all(0);
5434
5435 mutex_unlock(&ftrace_lock);
5436}
5437
5438static void *fpid_start(struct seq_file *m, loff_t *pos)
5439{
5440 mutex_lock(&ftrace_lock);
5441
5442 if (!ftrace_pids_enabled() && (!*pos))
5443 return (void *) 1;
5444
5445 return seq_list_start(&ftrace_pids, *pos);
5446}
5447
5448static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5449{
5450 if (v == (void *)1)
5451 return NULL;
5452
5453 return seq_list_next(v, &ftrace_pids, pos);
5454}
5455
5456static void fpid_stop(struct seq_file *m, void *p)
5457{
5458 mutex_unlock(&ftrace_lock);
5459}
5460
5461static int fpid_show(struct seq_file *m, void *v)
5462{
5463 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
5464
5465 if (v == (void *)1) {
5466 seq_puts(m, "no pid\n");
5467 return 0;
5468 }
5469
5470 if (fpid->pid == ftrace_swapper_pid)
5471 seq_puts(m, "swapper tasks\n");
5472 else
5473 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
5474
5475 return 0;
5476}
5477
5478static const struct seq_operations ftrace_pid_sops = {
5479 .start = fpid_start,
5480 .next = fpid_next,
5481 .stop = fpid_stop,
5482 .show = fpid_show,
5483};
5484
5485static int
5486ftrace_pid_open(struct inode *inode, struct file *file)
5487{
5488 int ret = 0;
5489
5490 if ((file->f_mode & FMODE_WRITE) &&
5491 (file->f_flags & O_TRUNC))
5492 ftrace_pid_reset();
5493
5494 if (file->f_mode & FMODE_READ)
5495 ret = seq_open(file, &ftrace_pid_sops);
5496
5497 return ret;
5498}
5499
5500static ssize_t
5501ftrace_pid_write(struct file *filp, const char __user *ubuf,
5502 size_t cnt, loff_t *ppos)
5503{
5504 char buf[64], *tmp;
5505 long val;
5506 int ret;
5507
5508 if (cnt >= sizeof(buf))
5509 return -EINVAL;
5510
5511 if (copy_from_user(&buf, ubuf, cnt))
5512 return -EFAULT;
5513
5514 buf[cnt] = 0;
5515
5516 /*
5517 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
5518 * to clean the filter quietly.
5519 */
5520 tmp = strstrip(buf);
5521 if (strlen(tmp) == 0)
5522 return 1;
5523
5524 ret = kstrtol(tmp, 10, &val);
5525 if (ret < 0)
5526 return ret;
5527
5528 ret = ftrace_pid_add(val);
5529
5530 return ret ? ret : cnt;
5531}
5532
5533static int
5534ftrace_pid_release(struct inode *inode, struct file *file)
5535{
5536 if (file->f_mode & FMODE_READ)
5537 seq_release(inode, file);
5538
5539 return 0;
5540}
5541
5542static const struct file_operations ftrace_pid_fops = {
5543 .open = ftrace_pid_open,
5544 .write = ftrace_pid_write,
5545 .read = seq_read,
5546 .llseek = tracing_lseek,
5547 .release = ftrace_pid_release,
5548};
5549
5550static __init int ftrace_init_tracefs(void)
5551{
5552 struct dentry *d_tracer;
5553
5554 d_tracer = tracing_init_dentry();
5555 if (IS_ERR(d_tracer))
5556 return 0;
5557
5558 ftrace_init_dyn_tracefs(d_tracer);
5559
5560 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5561 NULL, &ftrace_pid_fops);
5562
5563 ftrace_profile_tracefs(d_tracer);
5564
5565 return 0;
5566}
5567fs_initcall(ftrace_init_tracefs);
5568
5569/**
5570 * ftrace_kill - kill ftrace
5571 *
5572 * This function should be used by panic code. It stops ftrace
5573 * but in a not so nice way. If you need to simply kill ftrace
5574 * from a non-atomic section, use ftrace_kill.
5575 */
5576void ftrace_kill(void)
5577{
5578 ftrace_disabled = 1;
5579 ftrace_enabled = 0;
5580 clear_ftrace_function();
5581}
5582
5583/**
5584 * Test if ftrace is dead or not.
5585 */
5586int ftrace_is_dead(void)
5587{
5588 return ftrace_disabled;
5589}
5590
5591/**
5592 * register_ftrace_function - register a function for profiling
5593 * @ops - ops structure that holds the function for profiling.
5594 *
5595 * Register a function to be called by all functions in the
5596 * kernel.
5597 *
5598 * Note: @ops->func and all the functions it calls must be labeled
5599 * with "notrace", otherwise it will go into a
5600 * recursive loop.
5601 */
5602int register_ftrace_function(struct ftrace_ops *ops)
5603{
5604 int ret = -1;
5605
5606 ftrace_ops_init(ops);
5607
5608 mutex_lock(&ftrace_lock);
5609
5610 ret = ftrace_startup(ops, 0);
5611
5612 mutex_unlock(&ftrace_lock);
5613
5614 return ret;
5615}
5616EXPORT_SYMBOL_GPL(register_ftrace_function);
5617
5618/**
5619 * unregister_ftrace_function - unregister a function for profiling.
5620 * @ops - ops structure that holds the function to unregister
5621 *
5622 * Unregister a function that was added to be called by ftrace profiling.
5623 */
5624int unregister_ftrace_function(struct ftrace_ops *ops)
5625{
5626 int ret;
5627
5628 mutex_lock(&ftrace_lock);
5629 ret = ftrace_shutdown(ops, 0);
5630 mutex_unlock(&ftrace_lock);
5631
5632 return ret;
5633}
5634EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5635
5636int
5637ftrace_enable_sysctl(struct ctl_table *table, int write,
5638 void __user *buffer, size_t *lenp,
5639 loff_t *ppos)
5640{
5641 int ret = -ENODEV;
5642
5643 mutex_lock(&ftrace_lock);
5644
5645 if (unlikely(ftrace_disabled))
5646 goto out;
5647
5648 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5649
5650 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5651 goto out;
5652
5653 last_ftrace_enabled = !!ftrace_enabled;
5654
5655 if (ftrace_enabled) {
5656
5657 /* we are starting ftrace again */
5658 if (ftrace_ops_list != &ftrace_list_end)
5659 update_ftrace_function();
5660
5661 ftrace_startup_sysctl();
5662
5663 } else {
5664 /* stopping ftrace calls (just send to ftrace_stub) */
5665 ftrace_trace_function = ftrace_stub;
5666
5667 ftrace_shutdown_sysctl();
5668 }
5669
5670 out:
5671 mutex_unlock(&ftrace_lock);
5672 return ret;
5673}
5674
5675#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5676
5677static struct ftrace_ops graph_ops = {
5678 .func = ftrace_stub,
5679 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5680 FTRACE_OPS_FL_INITIALIZED |
5681 FTRACE_OPS_FL_PID |
5682 FTRACE_OPS_FL_STUB,
5683#ifdef FTRACE_GRAPH_TRAMP_ADDR
5684 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5685 /* trampoline_size is only needed for dynamically allocated tramps */
5686#endif
5687 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5688};
5689
5690void ftrace_graph_sleep_time_control(bool enable)
5691{
5692 fgraph_sleep_time = enable;
5693}
5694
5695void ftrace_graph_graph_time_control(bool enable)
5696{
5697 fgraph_graph_time = enable;
5698}
5699
5700int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5701{
5702 return 0;
5703}
5704
5705/* The callbacks that hook a function */
5706trace_func_graph_ret_t ftrace_graph_return =
5707 (trace_func_graph_ret_t)ftrace_stub;
5708trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5709static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5710
5711/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5712static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5713{
5714 int i;
5715 int ret = 0;
5716 unsigned long flags;
5717 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5718 struct task_struct *g, *t;
5719
5720 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5721 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5722 * sizeof(struct ftrace_ret_stack),
5723 GFP_KERNEL);
5724 if (!ret_stack_list[i]) {
5725 start = 0;
5726 end = i;
5727 ret = -ENOMEM;
5728 goto free;
5729 }
5730 }
5731
5732 read_lock_irqsave(&tasklist_lock, flags);
5733 do_each_thread(g, t) {
5734 if (start == end) {
5735 ret = -EAGAIN;
5736 goto unlock;
5737 }
5738
5739 if (t->ret_stack == NULL) {
5740 atomic_set(&t->tracing_graph_pause, 0);
5741 atomic_set(&t->trace_overrun, 0);
5742 t->curr_ret_stack = -1;
5743 /* Make sure the tasks see the -1 first: */
5744 smp_wmb();
5745 t->ret_stack = ret_stack_list[start++];
5746 }
5747 } while_each_thread(g, t);
5748
5749unlock:
5750 read_unlock_irqrestore(&tasklist_lock, flags);
5751free:
5752 for (i = start; i < end; i++)
5753 kfree(ret_stack_list[i]);
5754 return ret;
5755}
5756
5757static void
5758ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5759 struct task_struct *prev, struct task_struct *next)
5760{
5761 unsigned long long timestamp;
5762 int index;
5763
5764 /*
5765 * Does the user want to count the time a function was asleep.
5766 * If so, do not update the time stamps.
5767 */
5768 if (fgraph_sleep_time)
5769 return;
5770
5771 timestamp = trace_clock_local();
5772
5773 prev->ftrace_timestamp = timestamp;
5774
5775 /* only process tasks that we timestamped */
5776 if (!next->ftrace_timestamp)
5777 return;
5778
5779 /*
5780 * Update all the counters in next to make up for the
5781 * time next was sleeping.
5782 */
5783 timestamp -= next->ftrace_timestamp;
5784
5785 for (index = next->curr_ret_stack; index >= 0; index--)
5786 next->ret_stack[index].calltime += timestamp;
5787}
5788
5789/* Allocate a return stack for each task */
5790static int start_graph_tracing(void)
5791{
5792 struct ftrace_ret_stack **ret_stack_list;
5793 int ret, cpu;
5794
5795 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5796 sizeof(struct ftrace_ret_stack *),
5797 GFP_KERNEL);
5798
5799 if (!ret_stack_list)
5800 return -ENOMEM;
5801
5802 /* The cpu_boot init_task->ret_stack will never be freed */
5803 for_each_online_cpu(cpu) {
5804 if (!idle_task(cpu)->ret_stack)
5805 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5806 }
5807
5808 do {
5809 ret = alloc_retstack_tasklist(ret_stack_list);
5810 } while (ret == -EAGAIN);
5811
5812 if (!ret) {
5813 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5814 if (ret)
5815 pr_info("ftrace_graph: Couldn't activate tracepoint"
5816 " probe to kernel_sched_switch\n");
5817 }
5818
5819 kfree(ret_stack_list);
5820 return ret;
5821}
5822
5823/*
5824 * Hibernation protection.
5825 * The state of the current task is too much unstable during
5826 * suspend/restore to disk. We want to protect against that.
5827 */
5828static int
5829ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5830 void *unused)
5831{
5832 switch (state) {
5833 case PM_HIBERNATION_PREPARE:
5834 pause_graph_tracing();
5835 break;
5836
5837 case PM_POST_HIBERNATION:
5838 unpause_graph_tracing();
5839 break;
5840 }
5841 return NOTIFY_DONE;
5842}
5843
5844static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5845{
5846 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5847 return 0;
5848 return __ftrace_graph_entry(trace);
5849}
5850
5851/*
5852 * The function graph tracer should only trace the functions defined
5853 * by set_ftrace_filter and set_ftrace_notrace. If another function
5854 * tracer ops is registered, the graph tracer requires testing the
5855 * function against the global ops, and not just trace any function
5856 * that any ftrace_ops registered.
5857 */
5858static void update_function_graph_func(void)
5859{
5860 struct ftrace_ops *op;
5861 bool do_test = false;
5862
5863 /*
5864 * The graph and global ops share the same set of functions
5865 * to test. If any other ops is on the list, then
5866 * the graph tracing needs to test if its the function
5867 * it should call.
5868 */
5869 do_for_each_ftrace_op(op, ftrace_ops_list) {
5870 if (op != &global_ops && op != &graph_ops &&
5871 op != &ftrace_list_end) {
5872 do_test = true;
5873 /* in double loop, break out with goto */
5874 goto out;
5875 }
5876 } while_for_each_ftrace_op(op);
5877 out:
5878 if (do_test)
5879 ftrace_graph_entry = ftrace_graph_entry_test;
5880 else
5881 ftrace_graph_entry = __ftrace_graph_entry;
5882}
5883
5884static struct notifier_block ftrace_suspend_notifier = {
5885 .notifier_call = ftrace_suspend_notifier_call,
5886};
5887
5888int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5889 trace_func_graph_ent_t entryfunc)
5890{
5891 int ret = 0;
5892
5893 mutex_lock(&ftrace_lock);
5894
5895 /* we currently allow only one tracer registered at a time */
5896 if (ftrace_graph_active) {
5897 ret = -EBUSY;
5898 goto out;
5899 }
5900
5901 register_pm_notifier(&ftrace_suspend_notifier);
5902
5903 ftrace_graph_active++;
5904 ret = start_graph_tracing();
5905 if (ret) {
5906 ftrace_graph_active--;
5907 goto out;
5908 }
5909
5910 ftrace_graph_return = retfunc;
5911
5912 /*
5913 * Update the indirect function to the entryfunc, and the
5914 * function that gets called to the entry_test first. Then
5915 * call the update fgraph entry function to determine if
5916 * the entryfunc should be called directly or not.
5917 */
5918 __ftrace_graph_entry = entryfunc;
5919 ftrace_graph_entry = ftrace_graph_entry_test;
5920 update_function_graph_func();
5921
5922 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5923out:
5924 mutex_unlock(&ftrace_lock);
5925 return ret;
5926}
5927
5928void unregister_ftrace_graph(void)
5929{
5930 mutex_lock(&ftrace_lock);
5931
5932 if (unlikely(!ftrace_graph_active))
5933 goto out;
5934
5935 ftrace_graph_active--;
5936 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5937 ftrace_graph_entry = ftrace_graph_entry_stub;
5938 __ftrace_graph_entry = ftrace_graph_entry_stub;
5939 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5940 unregister_pm_notifier(&ftrace_suspend_notifier);
5941 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5942
5943#ifdef CONFIG_DYNAMIC_FTRACE
5944 /*
5945 * Function graph does not allocate the trampoline, but
5946 * other global_ops do. We need to reset the ALLOC_TRAMP flag
5947 * if one was used.
5948 */
5949 global_ops.trampoline = save_global_trampoline;
5950 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
5951 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
5952#endif
5953
5954 out:
5955 mutex_unlock(&ftrace_lock);
5956}
5957
5958static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5959
5960static void
5961graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5962{
5963 atomic_set(&t->tracing_graph_pause, 0);
5964 atomic_set(&t->trace_overrun, 0);
5965 t->ftrace_timestamp = 0;
5966 /* make curr_ret_stack visible before we add the ret_stack */
5967 smp_wmb();
5968 t->ret_stack = ret_stack;
5969}
5970
5971/*
5972 * Allocate a return stack for the idle task. May be the first
5973 * time through, or it may be done by CPU hotplug online.
5974 */
5975void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5976{
5977 t->curr_ret_stack = -1;
5978 /*
5979 * The idle task has no parent, it either has its own
5980 * stack or no stack at all.
5981 */
5982 if (t->ret_stack)
5983 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5984
5985 if (ftrace_graph_active) {
5986 struct ftrace_ret_stack *ret_stack;
5987
5988 ret_stack = per_cpu(idle_ret_stack, cpu);
5989 if (!ret_stack) {
5990 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5991 * sizeof(struct ftrace_ret_stack),
5992 GFP_KERNEL);
5993 if (!ret_stack)
5994 return;
5995 per_cpu(idle_ret_stack, cpu) = ret_stack;
5996 }
5997 graph_init_task(t, ret_stack);
5998 }
5999}
6000
6001/* Allocate a return stack for newly created task */
6002void ftrace_graph_init_task(struct task_struct *t)
6003{
6004 /* Make sure we do not use the parent ret_stack */
6005 t->ret_stack = NULL;
6006 t->curr_ret_stack = -1;
6007
6008 if (ftrace_graph_active) {
6009 struct ftrace_ret_stack *ret_stack;
6010
6011 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6012 * sizeof(struct ftrace_ret_stack),
6013 GFP_KERNEL);
6014 if (!ret_stack)
6015 return;
6016 graph_init_task(t, ret_stack);
6017 }
6018}
6019
6020void ftrace_graph_exit_task(struct task_struct *t)
6021{
6022 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6023
6024 t->ret_stack = NULL;
6025 /* NULL must become visible to IRQs before we free it: */
6026 barrier();
6027
6028 kfree(ret_stack);
6029}
6030#endif
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/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#ifdef CONFIG_DYNAMIC_FTRACE
68#define INIT_REGEX_LOCK(opsname) \
69 .regex_lock = __MUTEX_INITIALIZER(opsname.regex_lock),
70#else
71#define INIT_REGEX_LOCK(opsname)
72#endif
73
74static struct ftrace_ops ftrace_list_end __read_mostly = {
75 .func = ftrace_stub,
76 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
77};
78
79/* ftrace_enabled is a method to turn ftrace on or off */
80int ftrace_enabled __read_mostly;
81static int last_ftrace_enabled;
82
83/* Quick disabling of function tracer. */
84int function_trace_stop __read_mostly;
85
86/* Current function tracing op */
87struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
88/* What to set function_trace_op to */
89static struct ftrace_ops *set_function_trace_op;
90
91/* List for set_ftrace_pid's pids. */
92LIST_HEAD(ftrace_pids);
93struct ftrace_pid {
94 struct list_head list;
95 struct pid *pid;
96};
97
98/*
99 * ftrace_disabled is set when an anomaly is discovered.
100 * ftrace_disabled is much stronger than ftrace_enabled.
101 */
102static int ftrace_disabled __read_mostly;
103
104static DEFINE_MUTEX(ftrace_lock);
105
106static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
107static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
108static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
109ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
110ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
111static struct ftrace_ops global_ops;
112static struct ftrace_ops control_ops;
113
114#if ARCH_SUPPORTS_FTRACE_OPS
115static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
116 struct ftrace_ops *op, struct pt_regs *regs);
117#else
118/* See comment below, where ftrace_ops_list_func is defined */
119static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
120#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
121#endif
122
123/*
124 * Traverse the ftrace_global_list, invoking all entries. The reason that we
125 * can use rcu_dereference_raw_notrace() is that elements removed from this list
126 * are simply leaked, so there is no need to interact with a grace-period
127 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
128 * concurrent insertions into the ftrace_global_list.
129 *
130 * Silly Alpha and silly pointer-speculation compiler optimizations!
131 */
132#define do_for_each_ftrace_op(op, list) \
133 op = rcu_dereference_raw_notrace(list); \
134 do
135
136/*
137 * Optimized for just a single item in the list (as that is the normal case).
138 */
139#define while_for_each_ftrace_op(op) \
140 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
141 unlikely((op) != &ftrace_list_end))
142
143static inline void ftrace_ops_init(struct ftrace_ops *ops)
144{
145#ifdef CONFIG_DYNAMIC_FTRACE
146 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
147 mutex_init(&ops->regex_lock);
148 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
149 }
150#endif
151}
152
153/**
154 * ftrace_nr_registered_ops - return number of ops registered
155 *
156 * Returns the number of ftrace_ops registered and tracing functions
157 */
158int ftrace_nr_registered_ops(void)
159{
160 struct ftrace_ops *ops;
161 int cnt = 0;
162
163 mutex_lock(&ftrace_lock);
164
165 for (ops = ftrace_ops_list;
166 ops != &ftrace_list_end; ops = ops->next)
167 cnt++;
168
169 mutex_unlock(&ftrace_lock);
170
171 return cnt;
172}
173
174static void
175ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
176 struct ftrace_ops *op, struct pt_regs *regs)
177{
178 int bit;
179
180 bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
181 if (bit < 0)
182 return;
183
184 do_for_each_ftrace_op(op, ftrace_global_list) {
185 op->func(ip, parent_ip, op, regs);
186 } while_for_each_ftrace_op(op);
187
188 trace_clear_recursion(bit);
189}
190
191static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
192 struct ftrace_ops *op, struct pt_regs *regs)
193{
194 if (!test_tsk_trace_trace(current))
195 return;
196
197 ftrace_pid_function(ip, parent_ip, op, regs);
198}
199
200static void set_ftrace_pid_function(ftrace_func_t func)
201{
202 /* do not set ftrace_pid_function to itself! */
203 if (func != ftrace_pid_func)
204 ftrace_pid_function = func;
205}
206
207/**
208 * clear_ftrace_function - reset the ftrace function
209 *
210 * This NULLs the ftrace function and in essence stops
211 * tracing. There may be lag
212 */
213void clear_ftrace_function(void)
214{
215 ftrace_trace_function = ftrace_stub;
216 ftrace_pid_function = ftrace_stub;
217}
218
219static void control_ops_disable_all(struct ftrace_ops *ops)
220{
221 int cpu;
222
223 for_each_possible_cpu(cpu)
224 *per_cpu_ptr(ops->disabled, cpu) = 1;
225}
226
227static int control_ops_alloc(struct ftrace_ops *ops)
228{
229 int __percpu *disabled;
230
231 disabled = alloc_percpu(int);
232 if (!disabled)
233 return -ENOMEM;
234
235 ops->disabled = disabled;
236 control_ops_disable_all(ops);
237 return 0;
238}
239
240static void update_global_ops(void)
241{
242 ftrace_func_t func = ftrace_global_list_func;
243 void *private = NULL;
244
245 /* The list has its own recursion protection. */
246 global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
247
248 /*
249 * If there's only one function registered, then call that
250 * function directly. Otherwise, we need to iterate over the
251 * registered callers.
252 */
253 if (ftrace_global_list == &ftrace_list_end ||
254 ftrace_global_list->next == &ftrace_list_end) {
255 func = ftrace_global_list->func;
256 private = ftrace_global_list->private;
257 /*
258 * As we are calling the function directly.
259 * If it does not have recursion protection,
260 * the function_trace_op needs to be updated
261 * accordingly.
262 */
263 if (!(ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE))
264 global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
265 }
266
267 /* If we filter on pids, update to use the pid function */
268 if (!list_empty(&ftrace_pids)) {
269 set_ftrace_pid_function(func);
270 func = ftrace_pid_func;
271 }
272
273 global_ops.func = func;
274 global_ops.private = private;
275}
276
277static void ftrace_sync(struct work_struct *work)
278{
279 /*
280 * This function is just a stub to implement a hard force
281 * of synchronize_sched(). This requires synchronizing
282 * tasks even in userspace and idle.
283 *
284 * Yes, function tracing is rude.
285 */
286}
287
288static void ftrace_sync_ipi(void *data)
289{
290 /* Probably not needed, but do it anyway */
291 smp_rmb();
292}
293
294#ifdef CONFIG_FUNCTION_GRAPH_TRACER
295static void update_function_graph_func(void);
296#else
297static inline void update_function_graph_func(void) { }
298#endif
299
300static void update_ftrace_function(void)
301{
302 ftrace_func_t func;
303
304 update_global_ops();
305
306 /*
307 * If we are at the end of the list and this ops is
308 * recursion safe and not dynamic and the arch supports passing ops,
309 * then have the mcount trampoline call the function directly.
310 */
311 if (ftrace_ops_list == &ftrace_list_end ||
312 (ftrace_ops_list->next == &ftrace_list_end &&
313 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
314 (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
315 !FTRACE_FORCE_LIST_FUNC)) {
316 /* Set the ftrace_ops that the arch callback uses */
317 if (ftrace_ops_list == &global_ops)
318 set_function_trace_op = ftrace_global_list;
319 else
320 set_function_trace_op = ftrace_ops_list;
321 func = ftrace_ops_list->func;
322 } else {
323 /* Just use the default ftrace_ops */
324 set_function_trace_op = &ftrace_list_end;
325 func = ftrace_ops_list_func;
326 }
327
328 /* If there's no change, then do nothing more here */
329 if (ftrace_trace_function == func)
330 return;
331
332 update_function_graph_func();
333
334 /*
335 * If we are using the list function, it doesn't care
336 * about the function_trace_ops.
337 */
338 if (func == ftrace_ops_list_func) {
339 ftrace_trace_function = func;
340 /*
341 * Don't even bother setting function_trace_ops,
342 * it would be racy to do so anyway.
343 */
344 return;
345 }
346
347#ifndef CONFIG_DYNAMIC_FTRACE
348 /*
349 * For static tracing, we need to be a bit more careful.
350 * The function change takes affect immediately. Thus,
351 * we need to coorditate the setting of the function_trace_ops
352 * with the setting of the ftrace_trace_function.
353 *
354 * Set the function to the list ops, which will call the
355 * function we want, albeit indirectly, but it handles the
356 * ftrace_ops and doesn't depend on function_trace_op.
357 */
358 ftrace_trace_function = ftrace_ops_list_func;
359 /*
360 * Make sure all CPUs see this. Yes this is slow, but static
361 * tracing is slow and nasty to have enabled.
362 */
363 schedule_on_each_cpu(ftrace_sync);
364 /* Now all cpus are using the list ops. */
365 function_trace_op = set_function_trace_op;
366 /* Make sure the function_trace_op is visible on all CPUs */
367 smp_wmb();
368 /* Nasty way to force a rmb on all cpus */
369 smp_call_function(ftrace_sync_ipi, NULL, 1);
370 /* OK, we are all set to update the ftrace_trace_function now! */
371#endif /* !CONFIG_DYNAMIC_FTRACE */
372
373 ftrace_trace_function = func;
374}
375
376static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
377{
378 ops->next = *list;
379 /*
380 * We are entering ops into the list but another
381 * CPU might be walking that list. We need to make sure
382 * the ops->next pointer is valid before another CPU sees
383 * the ops pointer included into the list.
384 */
385 rcu_assign_pointer(*list, ops);
386}
387
388static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
389{
390 struct ftrace_ops **p;
391
392 /*
393 * If we are removing the last function, then simply point
394 * to the ftrace_stub.
395 */
396 if (*list == ops && ops->next == &ftrace_list_end) {
397 *list = &ftrace_list_end;
398 return 0;
399 }
400
401 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
402 if (*p == ops)
403 break;
404
405 if (*p != ops)
406 return -1;
407
408 *p = (*p)->next;
409 return 0;
410}
411
412static void add_ftrace_list_ops(struct ftrace_ops **list,
413 struct ftrace_ops *main_ops,
414 struct ftrace_ops *ops)
415{
416 int first = *list == &ftrace_list_end;
417 add_ftrace_ops(list, ops);
418 if (first)
419 add_ftrace_ops(&ftrace_ops_list, main_ops);
420}
421
422static int remove_ftrace_list_ops(struct ftrace_ops **list,
423 struct ftrace_ops *main_ops,
424 struct ftrace_ops *ops)
425{
426 int ret = remove_ftrace_ops(list, ops);
427 if (!ret && *list == &ftrace_list_end)
428 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
429 return ret;
430}
431
432static int __register_ftrace_function(struct ftrace_ops *ops)
433{
434 if (ops->flags & FTRACE_OPS_FL_DELETED)
435 return -EINVAL;
436
437 if (FTRACE_WARN_ON(ops == &global_ops))
438 return -EINVAL;
439
440 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
441 return -EBUSY;
442
443 /* We don't support both control and global flags set. */
444 if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
445 return -EINVAL;
446
447#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
448 /*
449 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
450 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
451 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
452 */
453 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
454 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
455 return -EINVAL;
456
457 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
458 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
459#endif
460
461 if (!core_kernel_data((unsigned long)ops))
462 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
463
464 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
465 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
466 ops->flags |= FTRACE_OPS_FL_ENABLED;
467 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
468 if (control_ops_alloc(ops))
469 return -ENOMEM;
470 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
471 } else
472 add_ftrace_ops(&ftrace_ops_list, ops);
473
474 if (ftrace_enabled)
475 update_ftrace_function();
476
477 return 0;
478}
479
480static int __unregister_ftrace_function(struct ftrace_ops *ops)
481{
482 int ret;
483
484 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
485 return -EBUSY;
486
487 if (FTRACE_WARN_ON(ops == &global_ops))
488 return -EINVAL;
489
490 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
491 ret = remove_ftrace_list_ops(&ftrace_global_list,
492 &global_ops, ops);
493 if (!ret)
494 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
495 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
496 ret = remove_ftrace_list_ops(&ftrace_control_list,
497 &control_ops, ops);
498 } else
499 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
500
501 if (ret < 0)
502 return ret;
503
504 if (ftrace_enabled)
505 update_ftrace_function();
506
507 return 0;
508}
509
510static void ftrace_update_pid_func(void)
511{
512 /* Only do something if we are tracing something */
513 if (ftrace_trace_function == ftrace_stub)
514 return;
515
516 update_ftrace_function();
517}
518
519#ifdef CONFIG_FUNCTION_PROFILER
520struct ftrace_profile {
521 struct hlist_node node;
522 unsigned long ip;
523 unsigned long counter;
524#ifdef CONFIG_FUNCTION_GRAPH_TRACER
525 unsigned long long time;
526 unsigned long long time_squared;
527#endif
528};
529
530struct ftrace_profile_page {
531 struct ftrace_profile_page *next;
532 unsigned long index;
533 struct ftrace_profile records[];
534};
535
536struct ftrace_profile_stat {
537 atomic_t disabled;
538 struct hlist_head *hash;
539 struct ftrace_profile_page *pages;
540 struct ftrace_profile_page *start;
541 struct tracer_stat stat;
542};
543
544#define PROFILE_RECORDS_SIZE \
545 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
546
547#define PROFILES_PER_PAGE \
548 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
549
550static int ftrace_profile_enabled __read_mostly;
551
552/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
553static DEFINE_MUTEX(ftrace_profile_lock);
554
555static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
556
557#define FTRACE_PROFILE_HASH_BITS 10
558#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
559
560static void *
561function_stat_next(void *v, int idx)
562{
563 struct ftrace_profile *rec = v;
564 struct ftrace_profile_page *pg;
565
566 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
567
568 again:
569 if (idx != 0)
570 rec++;
571
572 if ((void *)rec >= (void *)&pg->records[pg->index]) {
573 pg = pg->next;
574 if (!pg)
575 return NULL;
576 rec = &pg->records[0];
577 if (!rec->counter)
578 goto again;
579 }
580
581 return rec;
582}
583
584static void *function_stat_start(struct tracer_stat *trace)
585{
586 struct ftrace_profile_stat *stat =
587 container_of(trace, struct ftrace_profile_stat, stat);
588
589 if (!stat || !stat->start)
590 return NULL;
591
592 return function_stat_next(&stat->start->records[0], 0);
593}
594
595#ifdef CONFIG_FUNCTION_GRAPH_TRACER
596/* function graph compares on total time */
597static int function_stat_cmp(void *p1, void *p2)
598{
599 struct ftrace_profile *a = p1;
600 struct ftrace_profile *b = p2;
601
602 if (a->time < b->time)
603 return -1;
604 if (a->time > b->time)
605 return 1;
606 else
607 return 0;
608}
609#else
610/* not function graph compares against hits */
611static int function_stat_cmp(void *p1, void *p2)
612{
613 struct ftrace_profile *a = p1;
614 struct ftrace_profile *b = p2;
615
616 if (a->counter < b->counter)
617 return -1;
618 if (a->counter > b->counter)
619 return 1;
620 else
621 return 0;
622}
623#endif
624
625static int function_stat_headers(struct seq_file *m)
626{
627#ifdef CONFIG_FUNCTION_GRAPH_TRACER
628 seq_printf(m, " Function "
629 "Hit Time Avg s^2\n"
630 " -------- "
631 "--- ---- --- ---\n");
632#else
633 seq_printf(m, " Function Hit\n"
634 " -------- ---\n");
635#endif
636 return 0;
637}
638
639static int function_stat_show(struct seq_file *m, void *v)
640{
641 struct ftrace_profile *rec = v;
642 char str[KSYM_SYMBOL_LEN];
643 int ret = 0;
644#ifdef CONFIG_FUNCTION_GRAPH_TRACER
645 static struct trace_seq s;
646 unsigned long long avg;
647 unsigned long long stddev;
648#endif
649 mutex_lock(&ftrace_profile_lock);
650
651 /* we raced with function_profile_reset() */
652 if (unlikely(rec->counter == 0)) {
653 ret = -EBUSY;
654 goto out;
655 }
656
657 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
658 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
659
660#ifdef CONFIG_FUNCTION_GRAPH_TRACER
661 seq_printf(m, " ");
662 avg = rec->time;
663 do_div(avg, rec->counter);
664
665 /* Sample standard deviation (s^2) */
666 if (rec->counter <= 1)
667 stddev = 0;
668 else {
669 /*
670 * Apply Welford's method:
671 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
672 */
673 stddev = rec->counter * rec->time_squared -
674 rec->time * rec->time;
675
676 /*
677 * Divide only 1000 for ns^2 -> us^2 conversion.
678 * trace_print_graph_duration will divide 1000 again.
679 */
680 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
681 }
682
683 trace_seq_init(&s);
684 trace_print_graph_duration(rec->time, &s);
685 trace_seq_puts(&s, " ");
686 trace_print_graph_duration(avg, &s);
687 trace_seq_puts(&s, " ");
688 trace_print_graph_duration(stddev, &s);
689 trace_print_seq(m, &s);
690#endif
691 seq_putc(m, '\n');
692out:
693 mutex_unlock(&ftrace_profile_lock);
694
695 return ret;
696}
697
698static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
699{
700 struct ftrace_profile_page *pg;
701
702 pg = stat->pages = stat->start;
703
704 while (pg) {
705 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
706 pg->index = 0;
707 pg = pg->next;
708 }
709
710 memset(stat->hash, 0,
711 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
712}
713
714int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
715{
716 struct ftrace_profile_page *pg;
717 int functions;
718 int pages;
719 int i;
720
721 /* If we already allocated, do nothing */
722 if (stat->pages)
723 return 0;
724
725 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
726 if (!stat->pages)
727 return -ENOMEM;
728
729#ifdef CONFIG_DYNAMIC_FTRACE
730 functions = ftrace_update_tot_cnt;
731#else
732 /*
733 * We do not know the number of functions that exist because
734 * dynamic tracing is what counts them. With past experience
735 * we have around 20K functions. That should be more than enough.
736 * It is highly unlikely we will execute every function in
737 * the kernel.
738 */
739 functions = 20000;
740#endif
741
742 pg = stat->start = stat->pages;
743
744 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
745
746 for (i = 1; i < pages; i++) {
747 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
748 if (!pg->next)
749 goto out_free;
750 pg = pg->next;
751 }
752
753 return 0;
754
755 out_free:
756 pg = stat->start;
757 while (pg) {
758 unsigned long tmp = (unsigned long)pg;
759
760 pg = pg->next;
761 free_page(tmp);
762 }
763
764 stat->pages = NULL;
765 stat->start = NULL;
766
767 return -ENOMEM;
768}
769
770static int ftrace_profile_init_cpu(int cpu)
771{
772 struct ftrace_profile_stat *stat;
773 int size;
774
775 stat = &per_cpu(ftrace_profile_stats, cpu);
776
777 if (stat->hash) {
778 /* If the profile is already created, simply reset it */
779 ftrace_profile_reset(stat);
780 return 0;
781 }
782
783 /*
784 * We are profiling all functions, but usually only a few thousand
785 * functions are hit. We'll make a hash of 1024 items.
786 */
787 size = FTRACE_PROFILE_HASH_SIZE;
788
789 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
790
791 if (!stat->hash)
792 return -ENOMEM;
793
794 /* Preallocate the function profiling pages */
795 if (ftrace_profile_pages_init(stat) < 0) {
796 kfree(stat->hash);
797 stat->hash = NULL;
798 return -ENOMEM;
799 }
800
801 return 0;
802}
803
804static int ftrace_profile_init(void)
805{
806 int cpu;
807 int ret = 0;
808
809 for_each_possible_cpu(cpu) {
810 ret = ftrace_profile_init_cpu(cpu);
811 if (ret)
812 break;
813 }
814
815 return ret;
816}
817
818/* interrupts must be disabled */
819static struct ftrace_profile *
820ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
821{
822 struct ftrace_profile *rec;
823 struct hlist_head *hhd;
824 unsigned long key;
825
826 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
827 hhd = &stat->hash[key];
828
829 if (hlist_empty(hhd))
830 return NULL;
831
832 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
833 if (rec->ip == ip)
834 return rec;
835 }
836
837 return NULL;
838}
839
840static void ftrace_add_profile(struct ftrace_profile_stat *stat,
841 struct ftrace_profile *rec)
842{
843 unsigned long key;
844
845 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
846 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
847}
848
849/*
850 * The memory is already allocated, this simply finds a new record to use.
851 */
852static struct ftrace_profile *
853ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
854{
855 struct ftrace_profile *rec = NULL;
856
857 /* prevent recursion (from NMIs) */
858 if (atomic_inc_return(&stat->disabled) != 1)
859 goto out;
860
861 /*
862 * Try to find the function again since an NMI
863 * could have added it
864 */
865 rec = ftrace_find_profiled_func(stat, ip);
866 if (rec)
867 goto out;
868
869 if (stat->pages->index == PROFILES_PER_PAGE) {
870 if (!stat->pages->next)
871 goto out;
872 stat->pages = stat->pages->next;
873 }
874
875 rec = &stat->pages->records[stat->pages->index++];
876 rec->ip = ip;
877 ftrace_add_profile(stat, rec);
878
879 out:
880 atomic_dec(&stat->disabled);
881
882 return rec;
883}
884
885static void
886function_profile_call(unsigned long ip, unsigned long parent_ip,
887 struct ftrace_ops *ops, struct pt_regs *regs)
888{
889 struct ftrace_profile_stat *stat;
890 struct ftrace_profile *rec;
891 unsigned long flags;
892
893 if (!ftrace_profile_enabled)
894 return;
895
896 local_irq_save(flags);
897
898 stat = &__get_cpu_var(ftrace_profile_stats);
899 if (!stat->hash || !ftrace_profile_enabled)
900 goto out;
901
902 rec = ftrace_find_profiled_func(stat, ip);
903 if (!rec) {
904 rec = ftrace_profile_alloc(stat, ip);
905 if (!rec)
906 goto out;
907 }
908
909 rec->counter++;
910 out:
911 local_irq_restore(flags);
912}
913
914#ifdef CONFIG_FUNCTION_GRAPH_TRACER
915static int profile_graph_entry(struct ftrace_graph_ent *trace)
916{
917 function_profile_call(trace->func, 0, NULL, NULL);
918 return 1;
919}
920
921static void profile_graph_return(struct ftrace_graph_ret *trace)
922{
923 struct ftrace_profile_stat *stat;
924 unsigned long long calltime;
925 struct ftrace_profile *rec;
926 unsigned long flags;
927
928 local_irq_save(flags);
929 stat = &__get_cpu_var(ftrace_profile_stats);
930 if (!stat->hash || !ftrace_profile_enabled)
931 goto out;
932
933 /* If the calltime was zero'd ignore it */
934 if (!trace->calltime)
935 goto out;
936
937 calltime = trace->rettime - trace->calltime;
938
939 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
940 int index;
941
942 index = trace->depth;
943
944 /* Append this call time to the parent time to subtract */
945 if (index)
946 current->ret_stack[index - 1].subtime += calltime;
947
948 if (current->ret_stack[index].subtime < calltime)
949 calltime -= current->ret_stack[index].subtime;
950 else
951 calltime = 0;
952 }
953
954 rec = ftrace_find_profiled_func(stat, trace->func);
955 if (rec) {
956 rec->time += calltime;
957 rec->time_squared += calltime * calltime;
958 }
959
960 out:
961 local_irq_restore(flags);
962}
963
964static int register_ftrace_profiler(void)
965{
966 return register_ftrace_graph(&profile_graph_return,
967 &profile_graph_entry);
968}
969
970static void unregister_ftrace_profiler(void)
971{
972 unregister_ftrace_graph();
973}
974#else
975static struct ftrace_ops ftrace_profile_ops __read_mostly = {
976 .func = function_profile_call,
977 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
978 INIT_REGEX_LOCK(ftrace_profile_ops)
979};
980
981static int register_ftrace_profiler(void)
982{
983 return register_ftrace_function(&ftrace_profile_ops);
984}
985
986static void unregister_ftrace_profiler(void)
987{
988 unregister_ftrace_function(&ftrace_profile_ops);
989}
990#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
991
992static ssize_t
993ftrace_profile_write(struct file *filp, const char __user *ubuf,
994 size_t cnt, loff_t *ppos)
995{
996 unsigned long val;
997 int ret;
998
999 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1000 if (ret)
1001 return ret;
1002
1003 val = !!val;
1004
1005 mutex_lock(&ftrace_profile_lock);
1006 if (ftrace_profile_enabled ^ val) {
1007 if (val) {
1008 ret = ftrace_profile_init();
1009 if (ret < 0) {
1010 cnt = ret;
1011 goto out;
1012 }
1013
1014 ret = register_ftrace_profiler();
1015 if (ret < 0) {
1016 cnt = ret;
1017 goto out;
1018 }
1019 ftrace_profile_enabled = 1;
1020 } else {
1021 ftrace_profile_enabled = 0;
1022 /*
1023 * unregister_ftrace_profiler calls stop_machine
1024 * so this acts like an synchronize_sched.
1025 */
1026 unregister_ftrace_profiler();
1027 }
1028 }
1029 out:
1030 mutex_unlock(&ftrace_profile_lock);
1031
1032 *ppos += cnt;
1033
1034 return cnt;
1035}
1036
1037static ssize_t
1038ftrace_profile_read(struct file *filp, char __user *ubuf,
1039 size_t cnt, loff_t *ppos)
1040{
1041 char buf[64]; /* big enough to hold a number */
1042 int r;
1043
1044 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1045 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1046}
1047
1048static const struct file_operations ftrace_profile_fops = {
1049 .open = tracing_open_generic,
1050 .read = ftrace_profile_read,
1051 .write = ftrace_profile_write,
1052 .llseek = default_llseek,
1053};
1054
1055/* used to initialize the real stat files */
1056static struct tracer_stat function_stats __initdata = {
1057 .name = "functions",
1058 .stat_start = function_stat_start,
1059 .stat_next = function_stat_next,
1060 .stat_cmp = function_stat_cmp,
1061 .stat_headers = function_stat_headers,
1062 .stat_show = function_stat_show
1063};
1064
1065static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1066{
1067 struct ftrace_profile_stat *stat;
1068 struct dentry *entry;
1069 char *name;
1070 int ret;
1071 int cpu;
1072
1073 for_each_possible_cpu(cpu) {
1074 stat = &per_cpu(ftrace_profile_stats, cpu);
1075
1076 /* allocate enough for function name + cpu number */
1077 name = kmalloc(32, GFP_KERNEL);
1078 if (!name) {
1079 /*
1080 * The files created are permanent, if something happens
1081 * we still do not free memory.
1082 */
1083 WARN(1,
1084 "Could not allocate stat file for cpu %d\n",
1085 cpu);
1086 return;
1087 }
1088 stat->stat = function_stats;
1089 snprintf(name, 32, "function%d", cpu);
1090 stat->stat.name = name;
1091 ret = register_stat_tracer(&stat->stat);
1092 if (ret) {
1093 WARN(1,
1094 "Could not register function stat for cpu %d\n",
1095 cpu);
1096 kfree(name);
1097 return;
1098 }
1099 }
1100
1101 entry = debugfs_create_file("function_profile_enabled", 0644,
1102 d_tracer, NULL, &ftrace_profile_fops);
1103 if (!entry)
1104 pr_warning("Could not create debugfs "
1105 "'function_profile_enabled' entry\n");
1106}
1107
1108#else /* CONFIG_FUNCTION_PROFILER */
1109static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1110{
1111}
1112#endif /* CONFIG_FUNCTION_PROFILER */
1113
1114static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1115
1116#ifdef CONFIG_DYNAMIC_FTRACE
1117
1118#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1119# error Dynamic ftrace depends on MCOUNT_RECORD
1120#endif
1121
1122static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1123
1124struct ftrace_func_probe {
1125 struct hlist_node node;
1126 struct ftrace_probe_ops *ops;
1127 unsigned long flags;
1128 unsigned long ip;
1129 void *data;
1130 struct list_head free_list;
1131};
1132
1133struct ftrace_func_entry {
1134 struct hlist_node hlist;
1135 unsigned long ip;
1136};
1137
1138struct ftrace_hash {
1139 unsigned long size_bits;
1140 struct hlist_head *buckets;
1141 unsigned long count;
1142 struct rcu_head rcu;
1143};
1144
1145/*
1146 * We make these constant because no one should touch them,
1147 * but they are used as the default "empty hash", to avoid allocating
1148 * it all the time. These are in a read only section such that if
1149 * anyone does try to modify it, it will cause an exception.
1150 */
1151static const struct hlist_head empty_buckets[1];
1152static const struct ftrace_hash empty_hash = {
1153 .buckets = (struct hlist_head *)empty_buckets,
1154};
1155#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1156
1157static struct ftrace_ops global_ops = {
1158 .func = ftrace_stub,
1159 .notrace_hash = EMPTY_HASH,
1160 .filter_hash = EMPTY_HASH,
1161 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1162 INIT_REGEX_LOCK(global_ops)
1163};
1164
1165struct ftrace_page {
1166 struct ftrace_page *next;
1167 struct dyn_ftrace *records;
1168 int index;
1169 int size;
1170};
1171
1172#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1173#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1174
1175/* estimate from running different kernels */
1176#define NR_TO_INIT 10000
1177
1178static struct ftrace_page *ftrace_pages_start;
1179static struct ftrace_page *ftrace_pages;
1180
1181static bool ftrace_hash_empty(struct ftrace_hash *hash)
1182{
1183 return !hash || !hash->count;
1184}
1185
1186static struct ftrace_func_entry *
1187ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1188{
1189 unsigned long key;
1190 struct ftrace_func_entry *entry;
1191 struct hlist_head *hhd;
1192
1193 if (ftrace_hash_empty(hash))
1194 return NULL;
1195
1196 if (hash->size_bits > 0)
1197 key = hash_long(ip, hash->size_bits);
1198 else
1199 key = 0;
1200
1201 hhd = &hash->buckets[key];
1202
1203 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1204 if (entry->ip == ip)
1205 return entry;
1206 }
1207 return NULL;
1208}
1209
1210static void __add_hash_entry(struct ftrace_hash *hash,
1211 struct ftrace_func_entry *entry)
1212{
1213 struct hlist_head *hhd;
1214 unsigned long key;
1215
1216 if (hash->size_bits)
1217 key = hash_long(entry->ip, hash->size_bits);
1218 else
1219 key = 0;
1220
1221 hhd = &hash->buckets[key];
1222 hlist_add_head(&entry->hlist, hhd);
1223 hash->count++;
1224}
1225
1226static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1227{
1228 struct ftrace_func_entry *entry;
1229
1230 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1231 if (!entry)
1232 return -ENOMEM;
1233
1234 entry->ip = ip;
1235 __add_hash_entry(hash, entry);
1236
1237 return 0;
1238}
1239
1240static void
1241free_hash_entry(struct ftrace_hash *hash,
1242 struct ftrace_func_entry *entry)
1243{
1244 hlist_del(&entry->hlist);
1245 kfree(entry);
1246 hash->count--;
1247}
1248
1249static void
1250remove_hash_entry(struct ftrace_hash *hash,
1251 struct ftrace_func_entry *entry)
1252{
1253 hlist_del(&entry->hlist);
1254 hash->count--;
1255}
1256
1257static void ftrace_hash_clear(struct ftrace_hash *hash)
1258{
1259 struct hlist_head *hhd;
1260 struct hlist_node *tn;
1261 struct ftrace_func_entry *entry;
1262 int size = 1 << hash->size_bits;
1263 int i;
1264
1265 if (!hash->count)
1266 return;
1267
1268 for (i = 0; i < size; i++) {
1269 hhd = &hash->buckets[i];
1270 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1271 free_hash_entry(hash, entry);
1272 }
1273 FTRACE_WARN_ON(hash->count);
1274}
1275
1276static void free_ftrace_hash(struct ftrace_hash *hash)
1277{
1278 if (!hash || hash == EMPTY_HASH)
1279 return;
1280 ftrace_hash_clear(hash);
1281 kfree(hash->buckets);
1282 kfree(hash);
1283}
1284
1285static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1286{
1287 struct ftrace_hash *hash;
1288
1289 hash = container_of(rcu, struct ftrace_hash, rcu);
1290 free_ftrace_hash(hash);
1291}
1292
1293static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1294{
1295 if (!hash || hash == EMPTY_HASH)
1296 return;
1297 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1298}
1299
1300void ftrace_free_filter(struct ftrace_ops *ops)
1301{
1302 ftrace_ops_init(ops);
1303 free_ftrace_hash(ops->filter_hash);
1304 free_ftrace_hash(ops->notrace_hash);
1305}
1306
1307static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1308{
1309 struct ftrace_hash *hash;
1310 int size;
1311
1312 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1313 if (!hash)
1314 return NULL;
1315
1316 size = 1 << size_bits;
1317 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1318
1319 if (!hash->buckets) {
1320 kfree(hash);
1321 return NULL;
1322 }
1323
1324 hash->size_bits = size_bits;
1325
1326 return hash;
1327}
1328
1329static struct ftrace_hash *
1330alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1331{
1332 struct ftrace_func_entry *entry;
1333 struct ftrace_hash *new_hash;
1334 int size;
1335 int ret;
1336 int i;
1337
1338 new_hash = alloc_ftrace_hash(size_bits);
1339 if (!new_hash)
1340 return NULL;
1341
1342 /* Empty hash? */
1343 if (ftrace_hash_empty(hash))
1344 return new_hash;
1345
1346 size = 1 << hash->size_bits;
1347 for (i = 0; i < size; i++) {
1348 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1349 ret = add_hash_entry(new_hash, entry->ip);
1350 if (ret < 0)
1351 goto free_hash;
1352 }
1353 }
1354
1355 FTRACE_WARN_ON(new_hash->count != hash->count);
1356
1357 return new_hash;
1358
1359 free_hash:
1360 free_ftrace_hash(new_hash);
1361 return NULL;
1362}
1363
1364static void
1365ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1366static void
1367ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1368
1369static int
1370ftrace_hash_move(struct ftrace_ops *ops, int enable,
1371 struct ftrace_hash **dst, struct ftrace_hash *src)
1372{
1373 struct ftrace_func_entry *entry;
1374 struct hlist_node *tn;
1375 struct hlist_head *hhd;
1376 struct ftrace_hash *old_hash;
1377 struct ftrace_hash *new_hash;
1378 int size = src->count;
1379 int bits = 0;
1380 int ret;
1381 int i;
1382
1383 /*
1384 * Remove the current set, update the hash and add
1385 * them back.
1386 */
1387 ftrace_hash_rec_disable(ops, enable);
1388
1389 /*
1390 * If the new source is empty, just free dst and assign it
1391 * the empty_hash.
1392 */
1393 if (!src->count) {
1394 free_ftrace_hash_rcu(*dst);
1395 rcu_assign_pointer(*dst, EMPTY_HASH);
1396 /* still need to update the function records */
1397 ret = 0;
1398 goto out;
1399 }
1400
1401 /*
1402 * Make the hash size about 1/2 the # found
1403 */
1404 for (size /= 2; size; size >>= 1)
1405 bits++;
1406
1407 /* Don't allocate too much */
1408 if (bits > FTRACE_HASH_MAX_BITS)
1409 bits = FTRACE_HASH_MAX_BITS;
1410
1411 ret = -ENOMEM;
1412 new_hash = alloc_ftrace_hash(bits);
1413 if (!new_hash)
1414 goto out;
1415
1416 size = 1 << src->size_bits;
1417 for (i = 0; i < size; i++) {
1418 hhd = &src->buckets[i];
1419 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1420 remove_hash_entry(src, entry);
1421 __add_hash_entry(new_hash, entry);
1422 }
1423 }
1424
1425 old_hash = *dst;
1426 rcu_assign_pointer(*dst, new_hash);
1427 free_ftrace_hash_rcu(old_hash);
1428
1429 ret = 0;
1430 out:
1431 /*
1432 * Enable regardless of ret:
1433 * On success, we enable the new hash.
1434 * On failure, we re-enable the original hash.
1435 */
1436 ftrace_hash_rec_enable(ops, enable);
1437
1438 return ret;
1439}
1440
1441/*
1442 * Test the hashes for this ops to see if we want to call
1443 * the ops->func or not.
1444 *
1445 * It's a match if the ip is in the ops->filter_hash or
1446 * the filter_hash does not exist or is empty,
1447 * AND
1448 * the ip is not in the ops->notrace_hash.
1449 *
1450 * This needs to be called with preemption disabled as
1451 * the hashes are freed with call_rcu_sched().
1452 */
1453static int
1454ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1455{
1456 struct ftrace_hash *filter_hash;
1457 struct ftrace_hash *notrace_hash;
1458 int ret;
1459
1460#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1461 /*
1462 * There's a small race when adding ops that the ftrace handler
1463 * that wants regs, may be called without them. We can not
1464 * allow that handler to be called if regs is NULL.
1465 */
1466 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1467 return 0;
1468#endif
1469
1470 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1471 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1472
1473 if ((ftrace_hash_empty(filter_hash) ||
1474 ftrace_lookup_ip(filter_hash, ip)) &&
1475 (ftrace_hash_empty(notrace_hash) ||
1476 !ftrace_lookup_ip(notrace_hash, ip)))
1477 ret = 1;
1478 else
1479 ret = 0;
1480
1481 return ret;
1482}
1483
1484/*
1485 * This is a double for. Do not use 'break' to break out of the loop,
1486 * you must use a goto.
1487 */
1488#define do_for_each_ftrace_rec(pg, rec) \
1489 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1490 int _____i; \
1491 for (_____i = 0; _____i < pg->index; _____i++) { \
1492 rec = &pg->records[_____i];
1493
1494#define while_for_each_ftrace_rec() \
1495 } \
1496 }
1497
1498
1499static int ftrace_cmp_recs(const void *a, const void *b)
1500{
1501 const struct dyn_ftrace *key = a;
1502 const struct dyn_ftrace *rec = b;
1503
1504 if (key->flags < rec->ip)
1505 return -1;
1506 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1507 return 1;
1508 return 0;
1509}
1510
1511static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1512{
1513 struct ftrace_page *pg;
1514 struct dyn_ftrace *rec;
1515 struct dyn_ftrace key;
1516
1517 key.ip = start;
1518 key.flags = end; /* overload flags, as it is unsigned long */
1519
1520 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1521 if (end < pg->records[0].ip ||
1522 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1523 continue;
1524 rec = bsearch(&key, pg->records, pg->index,
1525 sizeof(struct dyn_ftrace),
1526 ftrace_cmp_recs);
1527 if (rec)
1528 return rec->ip;
1529 }
1530
1531 return 0;
1532}
1533
1534/**
1535 * ftrace_location - return true if the ip giving is a traced location
1536 * @ip: the instruction pointer to check
1537 *
1538 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1539 * That is, the instruction that is either a NOP or call to
1540 * the function tracer. It checks the ftrace internal tables to
1541 * determine if the address belongs or not.
1542 */
1543unsigned long ftrace_location(unsigned long ip)
1544{
1545 return ftrace_location_range(ip, ip);
1546}
1547
1548/**
1549 * ftrace_text_reserved - return true if range contains an ftrace location
1550 * @start: start of range to search
1551 * @end: end of range to search (inclusive). @end points to the last byte to check.
1552 *
1553 * Returns 1 if @start and @end contains a ftrace location.
1554 * That is, the instruction that is either a NOP or call to
1555 * the function tracer. It checks the ftrace internal tables to
1556 * determine if the address belongs or not.
1557 */
1558int ftrace_text_reserved(const void *start, const void *end)
1559{
1560 unsigned long ret;
1561
1562 ret = ftrace_location_range((unsigned long)start,
1563 (unsigned long)end);
1564
1565 return (int)!!ret;
1566}
1567
1568static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1569 int filter_hash,
1570 bool inc)
1571{
1572 struct ftrace_hash *hash;
1573 struct ftrace_hash *other_hash;
1574 struct ftrace_page *pg;
1575 struct dyn_ftrace *rec;
1576 int count = 0;
1577 int all = 0;
1578
1579 /* Only update if the ops has been registered */
1580 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1581 return;
1582
1583 /*
1584 * In the filter_hash case:
1585 * If the count is zero, we update all records.
1586 * Otherwise we just update the items in the hash.
1587 *
1588 * In the notrace_hash case:
1589 * We enable the update in the hash.
1590 * As disabling notrace means enabling the tracing,
1591 * and enabling notrace means disabling, the inc variable
1592 * gets inversed.
1593 */
1594 if (filter_hash) {
1595 hash = ops->filter_hash;
1596 other_hash = ops->notrace_hash;
1597 if (ftrace_hash_empty(hash))
1598 all = 1;
1599 } else {
1600 inc = !inc;
1601 hash = ops->notrace_hash;
1602 other_hash = ops->filter_hash;
1603 /*
1604 * If the notrace hash has no items,
1605 * then there's nothing to do.
1606 */
1607 if (ftrace_hash_empty(hash))
1608 return;
1609 }
1610
1611 do_for_each_ftrace_rec(pg, rec) {
1612 int in_other_hash = 0;
1613 int in_hash = 0;
1614 int match = 0;
1615
1616 if (all) {
1617 /*
1618 * Only the filter_hash affects all records.
1619 * Update if the record is not in the notrace hash.
1620 */
1621 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1622 match = 1;
1623 } else {
1624 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1625 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1626
1627 /*
1628 *
1629 */
1630 if (filter_hash && in_hash && !in_other_hash)
1631 match = 1;
1632 else if (!filter_hash && in_hash &&
1633 (in_other_hash || ftrace_hash_empty(other_hash)))
1634 match = 1;
1635 }
1636 if (!match)
1637 continue;
1638
1639 if (inc) {
1640 rec->flags++;
1641 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1642 return;
1643 /*
1644 * If any ops wants regs saved for this function
1645 * then all ops will get saved regs.
1646 */
1647 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1648 rec->flags |= FTRACE_FL_REGS;
1649 } else {
1650 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1651 return;
1652 rec->flags--;
1653 }
1654 count++;
1655 /* Shortcut, if we handled all records, we are done. */
1656 if (!all && count == hash->count)
1657 return;
1658 } while_for_each_ftrace_rec();
1659}
1660
1661static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1662 int filter_hash)
1663{
1664 __ftrace_hash_rec_update(ops, filter_hash, 0);
1665}
1666
1667static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1668 int filter_hash)
1669{
1670 __ftrace_hash_rec_update(ops, filter_hash, 1);
1671}
1672
1673static void print_ip_ins(const char *fmt, unsigned char *p)
1674{
1675 int i;
1676
1677 printk(KERN_CONT "%s", fmt);
1678
1679 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1680 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1681}
1682
1683/**
1684 * ftrace_bug - report and shutdown function tracer
1685 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1686 * @ip: The address that failed
1687 *
1688 * The arch code that enables or disables the function tracing
1689 * can call ftrace_bug() when it has detected a problem in
1690 * modifying the code. @failed should be one of either:
1691 * EFAULT - if the problem happens on reading the @ip address
1692 * EINVAL - if what is read at @ip is not what was expected
1693 * EPERM - if the problem happens on writting to the @ip address
1694 */
1695void ftrace_bug(int failed, unsigned long ip)
1696{
1697 switch (failed) {
1698 case -EFAULT:
1699 FTRACE_WARN_ON_ONCE(1);
1700 pr_info("ftrace faulted on modifying ");
1701 print_ip_sym(ip);
1702 break;
1703 case -EINVAL:
1704 FTRACE_WARN_ON_ONCE(1);
1705 pr_info("ftrace failed to modify ");
1706 print_ip_sym(ip);
1707 print_ip_ins(" actual: ", (unsigned char *)ip);
1708 printk(KERN_CONT "\n");
1709 break;
1710 case -EPERM:
1711 FTRACE_WARN_ON_ONCE(1);
1712 pr_info("ftrace faulted on writing ");
1713 print_ip_sym(ip);
1714 break;
1715 default:
1716 FTRACE_WARN_ON_ONCE(1);
1717 pr_info("ftrace faulted on unknown error ");
1718 print_ip_sym(ip);
1719 }
1720}
1721
1722static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1723{
1724 unsigned long flag = 0UL;
1725
1726 /*
1727 * If we are updating calls:
1728 *
1729 * If the record has a ref count, then we need to enable it
1730 * because someone is using it.
1731 *
1732 * Otherwise we make sure its disabled.
1733 *
1734 * If we are disabling calls, then disable all records that
1735 * are enabled.
1736 */
1737 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1738 flag = FTRACE_FL_ENABLED;
1739
1740 /*
1741 * If enabling and the REGS flag does not match the REGS_EN, then
1742 * do not ignore this record. Set flags to fail the compare against
1743 * ENABLED.
1744 */
1745 if (flag &&
1746 (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1747 flag |= FTRACE_FL_REGS;
1748
1749 /* If the state of this record hasn't changed, then do nothing */
1750 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1751 return FTRACE_UPDATE_IGNORE;
1752
1753 if (flag) {
1754 /* Save off if rec is being enabled (for return value) */
1755 flag ^= rec->flags & FTRACE_FL_ENABLED;
1756
1757 if (update) {
1758 rec->flags |= FTRACE_FL_ENABLED;
1759 if (flag & FTRACE_FL_REGS) {
1760 if (rec->flags & FTRACE_FL_REGS)
1761 rec->flags |= FTRACE_FL_REGS_EN;
1762 else
1763 rec->flags &= ~FTRACE_FL_REGS_EN;
1764 }
1765 }
1766
1767 /*
1768 * If this record is being updated from a nop, then
1769 * return UPDATE_MAKE_CALL.
1770 * Otherwise, if the EN flag is set, then return
1771 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1772 * from the non-save regs, to a save regs function.
1773 * Otherwise,
1774 * return UPDATE_MODIFY_CALL to tell the caller to convert
1775 * from the save regs, to a non-save regs function.
1776 */
1777 if (flag & FTRACE_FL_ENABLED)
1778 return FTRACE_UPDATE_MAKE_CALL;
1779 else if (rec->flags & FTRACE_FL_REGS_EN)
1780 return FTRACE_UPDATE_MODIFY_CALL_REGS;
1781 else
1782 return FTRACE_UPDATE_MODIFY_CALL;
1783 }
1784
1785 if (update) {
1786 /* If there's no more users, clear all flags */
1787 if (!(rec->flags & ~FTRACE_FL_MASK))
1788 rec->flags = 0;
1789 else
1790 /* Just disable the record (keep REGS state) */
1791 rec->flags &= ~FTRACE_FL_ENABLED;
1792 }
1793
1794 return FTRACE_UPDATE_MAKE_NOP;
1795}
1796
1797/**
1798 * ftrace_update_record, set a record that now is tracing or not
1799 * @rec: the record to update
1800 * @enable: set to 1 if the record is tracing, zero to force disable
1801 *
1802 * The records that represent all functions that can be traced need
1803 * to be updated when tracing has been enabled.
1804 */
1805int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1806{
1807 return ftrace_check_record(rec, enable, 1);
1808}
1809
1810/**
1811 * ftrace_test_record, check if the record has been enabled or not
1812 * @rec: the record to test
1813 * @enable: set to 1 to check if enabled, 0 if it is disabled
1814 *
1815 * The arch code may need to test if a record is already set to
1816 * tracing to determine how to modify the function code that it
1817 * represents.
1818 */
1819int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1820{
1821 return ftrace_check_record(rec, enable, 0);
1822}
1823
1824static int
1825__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1826{
1827 unsigned long ftrace_old_addr;
1828 unsigned long ftrace_addr;
1829 int ret;
1830
1831 ret = ftrace_update_record(rec, enable);
1832
1833 if (rec->flags & FTRACE_FL_REGS)
1834 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1835 else
1836 ftrace_addr = (unsigned long)FTRACE_ADDR;
1837
1838 switch (ret) {
1839 case FTRACE_UPDATE_IGNORE:
1840 return 0;
1841
1842 case FTRACE_UPDATE_MAKE_CALL:
1843 return ftrace_make_call(rec, ftrace_addr);
1844
1845 case FTRACE_UPDATE_MAKE_NOP:
1846 return ftrace_make_nop(NULL, rec, ftrace_addr);
1847
1848 case FTRACE_UPDATE_MODIFY_CALL_REGS:
1849 case FTRACE_UPDATE_MODIFY_CALL:
1850 if (rec->flags & FTRACE_FL_REGS)
1851 ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1852 else
1853 ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1854
1855 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1856 }
1857
1858 return -1; /* unknow ftrace bug */
1859}
1860
1861void __weak ftrace_replace_code(int enable)
1862{
1863 struct dyn_ftrace *rec;
1864 struct ftrace_page *pg;
1865 int failed;
1866
1867 if (unlikely(ftrace_disabled))
1868 return;
1869
1870 do_for_each_ftrace_rec(pg, rec) {
1871 failed = __ftrace_replace_code(rec, enable);
1872 if (failed) {
1873 ftrace_bug(failed, rec->ip);
1874 /* Stop processing */
1875 return;
1876 }
1877 } while_for_each_ftrace_rec();
1878}
1879
1880struct ftrace_rec_iter {
1881 struct ftrace_page *pg;
1882 int index;
1883};
1884
1885/**
1886 * ftrace_rec_iter_start, start up iterating over traced functions
1887 *
1888 * Returns an iterator handle that is used to iterate over all
1889 * the records that represent address locations where functions
1890 * are traced.
1891 *
1892 * May return NULL if no records are available.
1893 */
1894struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1895{
1896 /*
1897 * We only use a single iterator.
1898 * Protected by the ftrace_lock mutex.
1899 */
1900 static struct ftrace_rec_iter ftrace_rec_iter;
1901 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1902
1903 iter->pg = ftrace_pages_start;
1904 iter->index = 0;
1905
1906 /* Could have empty pages */
1907 while (iter->pg && !iter->pg->index)
1908 iter->pg = iter->pg->next;
1909
1910 if (!iter->pg)
1911 return NULL;
1912
1913 return iter;
1914}
1915
1916/**
1917 * ftrace_rec_iter_next, get the next record to process.
1918 * @iter: The handle to the iterator.
1919 *
1920 * Returns the next iterator after the given iterator @iter.
1921 */
1922struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1923{
1924 iter->index++;
1925
1926 if (iter->index >= iter->pg->index) {
1927 iter->pg = iter->pg->next;
1928 iter->index = 0;
1929
1930 /* Could have empty pages */
1931 while (iter->pg && !iter->pg->index)
1932 iter->pg = iter->pg->next;
1933 }
1934
1935 if (!iter->pg)
1936 return NULL;
1937
1938 return iter;
1939}
1940
1941/**
1942 * ftrace_rec_iter_record, get the record at the iterator location
1943 * @iter: The current iterator location
1944 *
1945 * Returns the record that the current @iter is at.
1946 */
1947struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1948{
1949 return &iter->pg->records[iter->index];
1950}
1951
1952static int
1953ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1954{
1955 unsigned long ip;
1956 int ret;
1957
1958 ip = rec->ip;
1959
1960 if (unlikely(ftrace_disabled))
1961 return 0;
1962
1963 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1964 if (ret) {
1965 ftrace_bug(ret, ip);
1966 return 0;
1967 }
1968 return 1;
1969}
1970
1971/*
1972 * archs can override this function if they must do something
1973 * before the modifying code is performed.
1974 */
1975int __weak ftrace_arch_code_modify_prepare(void)
1976{
1977 return 0;
1978}
1979
1980/*
1981 * archs can override this function if they must do something
1982 * after the modifying code is performed.
1983 */
1984int __weak ftrace_arch_code_modify_post_process(void)
1985{
1986 return 0;
1987}
1988
1989void ftrace_modify_all_code(int command)
1990{
1991 int update = command & FTRACE_UPDATE_TRACE_FUNC;
1992 int err = 0;
1993
1994 /*
1995 * If the ftrace_caller calls a ftrace_ops func directly,
1996 * we need to make sure that it only traces functions it
1997 * expects to trace. When doing the switch of functions,
1998 * we need to update to the ftrace_ops_list_func first
1999 * before the transition between old and new calls are set,
2000 * as the ftrace_ops_list_func will check the ops hashes
2001 * to make sure the ops are having the right functions
2002 * traced.
2003 */
2004 if (update) {
2005 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2006 if (FTRACE_WARN_ON(err))
2007 return;
2008 }
2009
2010 if (command & FTRACE_UPDATE_CALLS)
2011 ftrace_replace_code(1);
2012 else if (command & FTRACE_DISABLE_CALLS)
2013 ftrace_replace_code(0);
2014
2015 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2016 function_trace_op = set_function_trace_op;
2017 smp_wmb();
2018 /* If irqs are disabled, we are in stop machine */
2019 if (!irqs_disabled())
2020 smp_call_function(ftrace_sync_ipi, NULL, 1);
2021 err = ftrace_update_ftrace_func(ftrace_trace_function);
2022 if (FTRACE_WARN_ON(err))
2023 return;
2024 }
2025
2026 if (command & FTRACE_START_FUNC_RET)
2027 err = ftrace_enable_ftrace_graph_caller();
2028 else if (command & FTRACE_STOP_FUNC_RET)
2029 err = ftrace_disable_ftrace_graph_caller();
2030 FTRACE_WARN_ON(err);
2031}
2032
2033static int __ftrace_modify_code(void *data)
2034{
2035 int *command = data;
2036
2037 ftrace_modify_all_code(*command);
2038
2039 return 0;
2040}
2041
2042/**
2043 * ftrace_run_stop_machine, go back to the stop machine method
2044 * @command: The command to tell ftrace what to do
2045 *
2046 * If an arch needs to fall back to the stop machine method, the
2047 * it can call this function.
2048 */
2049void ftrace_run_stop_machine(int command)
2050{
2051 stop_machine(__ftrace_modify_code, &command, NULL);
2052}
2053
2054/**
2055 * arch_ftrace_update_code, modify the code to trace or not trace
2056 * @command: The command that needs to be done
2057 *
2058 * Archs can override this function if it does not need to
2059 * run stop_machine() to modify code.
2060 */
2061void __weak arch_ftrace_update_code(int command)
2062{
2063 ftrace_run_stop_machine(command);
2064}
2065
2066static void ftrace_run_update_code(int command)
2067{
2068 int ret;
2069
2070 ret = ftrace_arch_code_modify_prepare();
2071 FTRACE_WARN_ON(ret);
2072 if (ret)
2073 return;
2074 /*
2075 * Do not call function tracer while we update the code.
2076 * We are in stop machine.
2077 */
2078 function_trace_stop++;
2079
2080 /*
2081 * By default we use stop_machine() to modify the code.
2082 * But archs can do what ever they want as long as it
2083 * is safe. The stop_machine() is the safest, but also
2084 * produces the most overhead.
2085 */
2086 arch_ftrace_update_code(command);
2087
2088 function_trace_stop--;
2089
2090 ret = ftrace_arch_code_modify_post_process();
2091 FTRACE_WARN_ON(ret);
2092}
2093
2094static ftrace_func_t saved_ftrace_func;
2095static int ftrace_start_up;
2096static int global_start_up;
2097
2098static void control_ops_free(struct ftrace_ops *ops)
2099{
2100 free_percpu(ops->disabled);
2101}
2102
2103static void ftrace_startup_enable(int command)
2104{
2105 if (saved_ftrace_func != ftrace_trace_function) {
2106 saved_ftrace_func = ftrace_trace_function;
2107 command |= FTRACE_UPDATE_TRACE_FUNC;
2108 }
2109
2110 if (!command || !ftrace_enabled)
2111 return;
2112
2113 ftrace_run_update_code(command);
2114}
2115
2116static int ftrace_startup(struct ftrace_ops *ops, int command)
2117{
2118 bool hash_enable = true;
2119 int ret;
2120
2121 if (unlikely(ftrace_disabled))
2122 return -ENODEV;
2123
2124 ret = __register_ftrace_function(ops);
2125 if (ret)
2126 return ret;
2127
2128 ftrace_start_up++;
2129 command |= FTRACE_UPDATE_CALLS;
2130
2131 /* ops marked global share the filter hashes */
2132 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2133 ops = &global_ops;
2134 /* Don't update hash if global is already set */
2135 if (global_start_up)
2136 hash_enable = false;
2137 global_start_up++;
2138 }
2139
2140 ops->flags |= FTRACE_OPS_FL_ENABLED;
2141 if (hash_enable)
2142 ftrace_hash_rec_enable(ops, 1);
2143
2144 ftrace_startup_enable(command);
2145
2146 return 0;
2147}
2148
2149static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2150{
2151 bool hash_disable = true;
2152 int ret;
2153
2154 if (unlikely(ftrace_disabled))
2155 return -ENODEV;
2156
2157 ret = __unregister_ftrace_function(ops);
2158 if (ret)
2159 return ret;
2160
2161 ftrace_start_up--;
2162 /*
2163 * Just warn in case of unbalance, no need to kill ftrace, it's not
2164 * critical but the ftrace_call callers may be never nopped again after
2165 * further ftrace uses.
2166 */
2167 WARN_ON_ONCE(ftrace_start_up < 0);
2168
2169 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2170 ops = &global_ops;
2171 global_start_up--;
2172 WARN_ON_ONCE(global_start_up < 0);
2173 /* Don't update hash if global still has users */
2174 if (global_start_up) {
2175 WARN_ON_ONCE(!ftrace_start_up);
2176 hash_disable = false;
2177 }
2178 }
2179
2180 if (hash_disable)
2181 ftrace_hash_rec_disable(ops, 1);
2182
2183 if (ops != &global_ops || !global_start_up)
2184 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2185
2186 command |= FTRACE_UPDATE_CALLS;
2187
2188 if (saved_ftrace_func != ftrace_trace_function) {
2189 saved_ftrace_func = ftrace_trace_function;
2190 command |= FTRACE_UPDATE_TRACE_FUNC;
2191 }
2192
2193 if (!command || !ftrace_enabled) {
2194 /*
2195 * If these are control ops, they still need their
2196 * per_cpu field freed. Since, function tracing is
2197 * not currently active, we can just free them
2198 * without synchronizing all CPUs.
2199 */
2200 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2201 control_ops_free(ops);
2202 return 0;
2203 }
2204
2205 ftrace_run_update_code(command);
2206
2207 /*
2208 * Dynamic ops may be freed, we must make sure that all
2209 * callers are done before leaving this function.
2210 * The same goes for freeing the per_cpu data of the control
2211 * ops.
2212 *
2213 * Again, normal synchronize_sched() is not good enough.
2214 * We need to do a hard force of sched synchronization.
2215 * This is because we use preempt_disable() to do RCU, but
2216 * the function tracers can be called where RCU is not watching
2217 * (like before user_exit()). We can not rely on the RCU
2218 * infrastructure to do the synchronization, thus we must do it
2219 * ourselves.
2220 */
2221 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2222 schedule_on_each_cpu(ftrace_sync);
2223
2224 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2225 control_ops_free(ops);
2226 }
2227
2228 return 0;
2229}
2230
2231static void ftrace_startup_sysctl(void)
2232{
2233 if (unlikely(ftrace_disabled))
2234 return;
2235
2236 /* Force update next time */
2237 saved_ftrace_func = NULL;
2238 /* ftrace_start_up is true if we want ftrace running */
2239 if (ftrace_start_up)
2240 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2241}
2242
2243static void ftrace_shutdown_sysctl(void)
2244{
2245 if (unlikely(ftrace_disabled))
2246 return;
2247
2248 /* ftrace_start_up is true if ftrace is running */
2249 if (ftrace_start_up)
2250 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2251}
2252
2253static cycle_t ftrace_update_time;
2254unsigned long ftrace_update_tot_cnt;
2255
2256static inline int ops_traces_mod(struct ftrace_ops *ops)
2257{
2258 /*
2259 * Filter_hash being empty will default to trace module.
2260 * But notrace hash requires a test of individual module functions.
2261 */
2262 return ftrace_hash_empty(ops->filter_hash) &&
2263 ftrace_hash_empty(ops->notrace_hash);
2264}
2265
2266/*
2267 * Check if the current ops references the record.
2268 *
2269 * If the ops traces all functions, then it was already accounted for.
2270 * If the ops does not trace the current record function, skip it.
2271 * If the ops ignores the function via notrace filter, skip it.
2272 */
2273static inline bool
2274ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2275{
2276 /* If ops isn't enabled, ignore it */
2277 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2278 return 0;
2279
2280 /* If ops traces all mods, we already accounted for it */
2281 if (ops_traces_mod(ops))
2282 return 0;
2283
2284 /* The function must be in the filter */
2285 if (!ftrace_hash_empty(ops->filter_hash) &&
2286 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2287 return 0;
2288
2289 /* If in notrace hash, we ignore it too */
2290 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2291 return 0;
2292
2293 return 1;
2294}
2295
2296static int referenced_filters(struct dyn_ftrace *rec)
2297{
2298 struct ftrace_ops *ops;
2299 int cnt = 0;
2300
2301 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2302 if (ops_references_rec(ops, rec))
2303 cnt++;
2304 }
2305
2306 return cnt;
2307}
2308
2309static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2310{
2311 struct ftrace_page *pg;
2312 struct dyn_ftrace *p;
2313 cycle_t start, stop;
2314 unsigned long update_cnt = 0;
2315 unsigned long ref = 0;
2316 bool test = false;
2317 int i;
2318
2319 /*
2320 * When adding a module, we need to check if tracers are
2321 * currently enabled and if they are set to trace all functions.
2322 * If they are, we need to enable the module functions as well
2323 * as update the reference counts for those function records.
2324 */
2325 if (mod) {
2326 struct ftrace_ops *ops;
2327
2328 for (ops = ftrace_ops_list;
2329 ops != &ftrace_list_end; ops = ops->next) {
2330 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2331 if (ops_traces_mod(ops))
2332 ref++;
2333 else
2334 test = true;
2335 }
2336 }
2337 }
2338
2339 start = ftrace_now(raw_smp_processor_id());
2340
2341 for (pg = new_pgs; pg; pg = pg->next) {
2342
2343 for (i = 0; i < pg->index; i++) {
2344 int cnt = ref;
2345
2346 /* If something went wrong, bail without enabling anything */
2347 if (unlikely(ftrace_disabled))
2348 return -1;
2349
2350 p = &pg->records[i];
2351 if (test)
2352 cnt += referenced_filters(p);
2353 p->flags = cnt;
2354
2355 /*
2356 * Do the initial record conversion from mcount jump
2357 * to the NOP instructions.
2358 */
2359 if (!ftrace_code_disable(mod, p))
2360 break;
2361
2362 update_cnt++;
2363
2364 /*
2365 * If the tracing is enabled, go ahead and enable the record.
2366 *
2367 * The reason not to enable the record immediatelly is the
2368 * inherent check of ftrace_make_nop/ftrace_make_call for
2369 * correct previous instructions. Making first the NOP
2370 * conversion puts the module to the correct state, thus
2371 * passing the ftrace_make_call check.
2372 */
2373 if (ftrace_start_up && cnt) {
2374 int failed = __ftrace_replace_code(p, 1);
2375 if (failed)
2376 ftrace_bug(failed, p->ip);
2377 }
2378 }
2379 }
2380
2381 stop = ftrace_now(raw_smp_processor_id());
2382 ftrace_update_time = stop - start;
2383 ftrace_update_tot_cnt += update_cnt;
2384
2385 return 0;
2386}
2387
2388static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2389{
2390 int order;
2391 int cnt;
2392
2393 if (WARN_ON(!count))
2394 return -EINVAL;
2395
2396 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2397
2398 /*
2399 * We want to fill as much as possible. No more than a page
2400 * may be empty.
2401 */
2402 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2403 order--;
2404
2405 again:
2406 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2407
2408 if (!pg->records) {
2409 /* if we can't allocate this size, try something smaller */
2410 if (!order)
2411 return -ENOMEM;
2412 order >>= 1;
2413 goto again;
2414 }
2415
2416 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2417 pg->size = cnt;
2418
2419 if (cnt > count)
2420 cnt = count;
2421
2422 return cnt;
2423}
2424
2425static struct ftrace_page *
2426ftrace_allocate_pages(unsigned long num_to_init)
2427{
2428 struct ftrace_page *start_pg;
2429 struct ftrace_page *pg;
2430 int order;
2431 int cnt;
2432
2433 if (!num_to_init)
2434 return 0;
2435
2436 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2437 if (!pg)
2438 return NULL;
2439
2440 /*
2441 * Try to allocate as much as possible in one continues
2442 * location that fills in all of the space. We want to
2443 * waste as little space as possible.
2444 */
2445 for (;;) {
2446 cnt = ftrace_allocate_records(pg, num_to_init);
2447 if (cnt < 0)
2448 goto free_pages;
2449
2450 num_to_init -= cnt;
2451 if (!num_to_init)
2452 break;
2453
2454 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2455 if (!pg->next)
2456 goto free_pages;
2457
2458 pg = pg->next;
2459 }
2460
2461 return start_pg;
2462
2463 free_pages:
2464 while (start_pg) {
2465 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2466 free_pages((unsigned long)pg->records, order);
2467 start_pg = pg->next;
2468 kfree(pg);
2469 pg = start_pg;
2470 }
2471 pr_info("ftrace: FAILED to allocate memory for functions\n");
2472 return NULL;
2473}
2474
2475#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2476
2477struct ftrace_iterator {
2478 loff_t pos;
2479 loff_t func_pos;
2480 struct ftrace_page *pg;
2481 struct dyn_ftrace *func;
2482 struct ftrace_func_probe *probe;
2483 struct trace_parser parser;
2484 struct ftrace_hash *hash;
2485 struct ftrace_ops *ops;
2486 int hidx;
2487 int idx;
2488 unsigned flags;
2489};
2490
2491static void *
2492t_hash_next(struct seq_file *m, loff_t *pos)
2493{
2494 struct ftrace_iterator *iter = m->private;
2495 struct hlist_node *hnd = NULL;
2496 struct hlist_head *hhd;
2497
2498 (*pos)++;
2499 iter->pos = *pos;
2500
2501 if (iter->probe)
2502 hnd = &iter->probe->node;
2503 retry:
2504 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2505 return NULL;
2506
2507 hhd = &ftrace_func_hash[iter->hidx];
2508
2509 if (hlist_empty(hhd)) {
2510 iter->hidx++;
2511 hnd = NULL;
2512 goto retry;
2513 }
2514
2515 if (!hnd)
2516 hnd = hhd->first;
2517 else {
2518 hnd = hnd->next;
2519 if (!hnd) {
2520 iter->hidx++;
2521 goto retry;
2522 }
2523 }
2524
2525 if (WARN_ON_ONCE(!hnd))
2526 return NULL;
2527
2528 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2529
2530 return iter;
2531}
2532
2533static void *t_hash_start(struct seq_file *m, loff_t *pos)
2534{
2535 struct ftrace_iterator *iter = m->private;
2536 void *p = NULL;
2537 loff_t l;
2538
2539 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2540 return NULL;
2541
2542 if (iter->func_pos > *pos)
2543 return NULL;
2544
2545 iter->hidx = 0;
2546 for (l = 0; l <= (*pos - iter->func_pos); ) {
2547 p = t_hash_next(m, &l);
2548 if (!p)
2549 break;
2550 }
2551 if (!p)
2552 return NULL;
2553
2554 /* Only set this if we have an item */
2555 iter->flags |= FTRACE_ITER_HASH;
2556
2557 return iter;
2558}
2559
2560static int
2561t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2562{
2563 struct ftrace_func_probe *rec;
2564
2565 rec = iter->probe;
2566 if (WARN_ON_ONCE(!rec))
2567 return -EIO;
2568
2569 if (rec->ops->print)
2570 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2571
2572 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2573
2574 if (rec->data)
2575 seq_printf(m, ":%p", rec->data);
2576 seq_putc(m, '\n');
2577
2578 return 0;
2579}
2580
2581static void *
2582t_next(struct seq_file *m, void *v, loff_t *pos)
2583{
2584 struct ftrace_iterator *iter = m->private;
2585 struct ftrace_ops *ops = iter->ops;
2586 struct dyn_ftrace *rec = NULL;
2587
2588 if (unlikely(ftrace_disabled))
2589 return NULL;
2590
2591 if (iter->flags & FTRACE_ITER_HASH)
2592 return t_hash_next(m, pos);
2593
2594 (*pos)++;
2595 iter->pos = iter->func_pos = *pos;
2596
2597 if (iter->flags & FTRACE_ITER_PRINTALL)
2598 return t_hash_start(m, pos);
2599
2600 retry:
2601 if (iter->idx >= iter->pg->index) {
2602 if (iter->pg->next) {
2603 iter->pg = iter->pg->next;
2604 iter->idx = 0;
2605 goto retry;
2606 }
2607 } else {
2608 rec = &iter->pg->records[iter->idx++];
2609 if (((iter->flags & FTRACE_ITER_FILTER) &&
2610 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2611
2612 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2613 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2614
2615 ((iter->flags & FTRACE_ITER_ENABLED) &&
2616 !(rec->flags & FTRACE_FL_ENABLED))) {
2617
2618 rec = NULL;
2619 goto retry;
2620 }
2621 }
2622
2623 if (!rec)
2624 return t_hash_start(m, pos);
2625
2626 iter->func = rec;
2627
2628 return iter;
2629}
2630
2631static void reset_iter_read(struct ftrace_iterator *iter)
2632{
2633 iter->pos = 0;
2634 iter->func_pos = 0;
2635 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2636}
2637
2638static void *t_start(struct seq_file *m, loff_t *pos)
2639{
2640 struct ftrace_iterator *iter = m->private;
2641 struct ftrace_ops *ops = iter->ops;
2642 void *p = NULL;
2643 loff_t l;
2644
2645 mutex_lock(&ftrace_lock);
2646
2647 if (unlikely(ftrace_disabled))
2648 return NULL;
2649
2650 /*
2651 * If an lseek was done, then reset and start from beginning.
2652 */
2653 if (*pos < iter->pos)
2654 reset_iter_read(iter);
2655
2656 /*
2657 * For set_ftrace_filter reading, if we have the filter
2658 * off, we can short cut and just print out that all
2659 * functions are enabled.
2660 */
2661 if (iter->flags & FTRACE_ITER_FILTER &&
2662 ftrace_hash_empty(ops->filter_hash)) {
2663 if (*pos > 0)
2664 return t_hash_start(m, pos);
2665 iter->flags |= FTRACE_ITER_PRINTALL;
2666 /* reset in case of seek/pread */
2667 iter->flags &= ~FTRACE_ITER_HASH;
2668 return iter;
2669 }
2670
2671 if (iter->flags & FTRACE_ITER_HASH)
2672 return t_hash_start(m, pos);
2673
2674 /*
2675 * Unfortunately, we need to restart at ftrace_pages_start
2676 * every time we let go of the ftrace_mutex. This is because
2677 * those pointers can change without the lock.
2678 */
2679 iter->pg = ftrace_pages_start;
2680 iter->idx = 0;
2681 for (l = 0; l <= *pos; ) {
2682 p = t_next(m, p, &l);
2683 if (!p)
2684 break;
2685 }
2686
2687 if (!p)
2688 return t_hash_start(m, pos);
2689
2690 return iter;
2691}
2692
2693static void t_stop(struct seq_file *m, void *p)
2694{
2695 mutex_unlock(&ftrace_lock);
2696}
2697
2698static int t_show(struct seq_file *m, void *v)
2699{
2700 struct ftrace_iterator *iter = m->private;
2701 struct dyn_ftrace *rec;
2702
2703 if (iter->flags & FTRACE_ITER_HASH)
2704 return t_hash_show(m, iter);
2705
2706 if (iter->flags & FTRACE_ITER_PRINTALL) {
2707 seq_printf(m, "#### all functions enabled ####\n");
2708 return 0;
2709 }
2710
2711 rec = iter->func;
2712
2713 if (!rec)
2714 return 0;
2715
2716 seq_printf(m, "%ps", (void *)rec->ip);
2717 if (iter->flags & FTRACE_ITER_ENABLED)
2718 seq_printf(m, " (%ld)%s",
2719 rec->flags & ~FTRACE_FL_MASK,
2720 rec->flags & FTRACE_FL_REGS ? " R" : "");
2721 seq_printf(m, "\n");
2722
2723 return 0;
2724}
2725
2726static const struct seq_operations show_ftrace_seq_ops = {
2727 .start = t_start,
2728 .next = t_next,
2729 .stop = t_stop,
2730 .show = t_show,
2731};
2732
2733static int
2734ftrace_avail_open(struct inode *inode, struct file *file)
2735{
2736 struct ftrace_iterator *iter;
2737
2738 if (unlikely(ftrace_disabled))
2739 return -ENODEV;
2740
2741 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2742 if (iter) {
2743 iter->pg = ftrace_pages_start;
2744 iter->ops = &global_ops;
2745 }
2746
2747 return iter ? 0 : -ENOMEM;
2748}
2749
2750static int
2751ftrace_enabled_open(struct inode *inode, struct file *file)
2752{
2753 struct ftrace_iterator *iter;
2754
2755 if (unlikely(ftrace_disabled))
2756 return -ENODEV;
2757
2758 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2759 if (iter) {
2760 iter->pg = ftrace_pages_start;
2761 iter->flags = FTRACE_ITER_ENABLED;
2762 iter->ops = &global_ops;
2763 }
2764
2765 return iter ? 0 : -ENOMEM;
2766}
2767
2768static void ftrace_filter_reset(struct ftrace_hash *hash)
2769{
2770 mutex_lock(&ftrace_lock);
2771 ftrace_hash_clear(hash);
2772 mutex_unlock(&ftrace_lock);
2773}
2774
2775/**
2776 * ftrace_regex_open - initialize function tracer filter files
2777 * @ops: The ftrace_ops that hold the hash filters
2778 * @flag: The type of filter to process
2779 * @inode: The inode, usually passed in to your open routine
2780 * @file: The file, usually passed in to your open routine
2781 *
2782 * ftrace_regex_open() initializes the filter files for the
2783 * @ops. Depending on @flag it may process the filter hash or
2784 * the notrace hash of @ops. With this called from the open
2785 * routine, you can use ftrace_filter_write() for the write
2786 * routine if @flag has FTRACE_ITER_FILTER set, or
2787 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2788 * tracing_lseek() should be used as the lseek routine, and
2789 * release must call ftrace_regex_release().
2790 */
2791int
2792ftrace_regex_open(struct ftrace_ops *ops, int flag,
2793 struct inode *inode, struct file *file)
2794{
2795 struct ftrace_iterator *iter;
2796 struct ftrace_hash *hash;
2797 int ret = 0;
2798
2799 ftrace_ops_init(ops);
2800
2801 if (unlikely(ftrace_disabled))
2802 return -ENODEV;
2803
2804 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2805 if (!iter)
2806 return -ENOMEM;
2807
2808 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2809 kfree(iter);
2810 return -ENOMEM;
2811 }
2812
2813 iter->ops = ops;
2814 iter->flags = flag;
2815
2816 mutex_lock(&ops->regex_lock);
2817
2818 if (flag & FTRACE_ITER_NOTRACE)
2819 hash = ops->notrace_hash;
2820 else
2821 hash = ops->filter_hash;
2822
2823 if (file->f_mode & FMODE_WRITE) {
2824 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2825 if (!iter->hash) {
2826 trace_parser_put(&iter->parser);
2827 kfree(iter);
2828 ret = -ENOMEM;
2829 goto out_unlock;
2830 }
2831 }
2832
2833 if ((file->f_mode & FMODE_WRITE) &&
2834 (file->f_flags & O_TRUNC))
2835 ftrace_filter_reset(iter->hash);
2836
2837 if (file->f_mode & FMODE_READ) {
2838 iter->pg = ftrace_pages_start;
2839
2840 ret = seq_open(file, &show_ftrace_seq_ops);
2841 if (!ret) {
2842 struct seq_file *m = file->private_data;
2843 m->private = iter;
2844 } else {
2845 /* Failed */
2846 free_ftrace_hash(iter->hash);
2847 trace_parser_put(&iter->parser);
2848 kfree(iter);
2849 }
2850 } else
2851 file->private_data = iter;
2852
2853 out_unlock:
2854 mutex_unlock(&ops->regex_lock);
2855
2856 return ret;
2857}
2858
2859static int
2860ftrace_filter_open(struct inode *inode, struct file *file)
2861{
2862 struct ftrace_ops *ops = inode->i_private;
2863
2864 return ftrace_regex_open(ops,
2865 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2866 inode, file);
2867}
2868
2869static int
2870ftrace_notrace_open(struct inode *inode, struct file *file)
2871{
2872 struct ftrace_ops *ops = inode->i_private;
2873
2874 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
2875 inode, file);
2876}
2877
2878static int ftrace_match(char *str, char *regex, int len, int type)
2879{
2880 int matched = 0;
2881 int slen;
2882
2883 switch (type) {
2884 case MATCH_FULL:
2885 if (strcmp(str, regex) == 0)
2886 matched = 1;
2887 break;
2888 case MATCH_FRONT_ONLY:
2889 if (strncmp(str, regex, len) == 0)
2890 matched = 1;
2891 break;
2892 case MATCH_MIDDLE_ONLY:
2893 if (strstr(str, regex))
2894 matched = 1;
2895 break;
2896 case MATCH_END_ONLY:
2897 slen = strlen(str);
2898 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2899 matched = 1;
2900 break;
2901 }
2902
2903 return matched;
2904}
2905
2906static int
2907enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2908{
2909 struct ftrace_func_entry *entry;
2910 int ret = 0;
2911
2912 entry = ftrace_lookup_ip(hash, rec->ip);
2913 if (not) {
2914 /* Do nothing if it doesn't exist */
2915 if (!entry)
2916 return 0;
2917
2918 free_hash_entry(hash, entry);
2919 } else {
2920 /* Do nothing if it exists */
2921 if (entry)
2922 return 0;
2923
2924 ret = add_hash_entry(hash, rec->ip);
2925 }
2926 return ret;
2927}
2928
2929static int
2930ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2931 char *regex, int len, int type)
2932{
2933 char str[KSYM_SYMBOL_LEN];
2934 char *modname;
2935
2936 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2937
2938 if (mod) {
2939 /* module lookup requires matching the module */
2940 if (!modname || strcmp(modname, mod))
2941 return 0;
2942
2943 /* blank search means to match all funcs in the mod */
2944 if (!len)
2945 return 1;
2946 }
2947
2948 return ftrace_match(str, regex, len, type);
2949}
2950
2951static int
2952match_records(struct ftrace_hash *hash, char *buff,
2953 int len, char *mod, int not)
2954{
2955 unsigned search_len = 0;
2956 struct ftrace_page *pg;
2957 struct dyn_ftrace *rec;
2958 int type = MATCH_FULL;
2959 char *search = buff;
2960 int found = 0;
2961 int ret;
2962
2963 if (len) {
2964 type = filter_parse_regex(buff, len, &search, ¬);
2965 search_len = strlen(search);
2966 }
2967
2968 mutex_lock(&ftrace_lock);
2969
2970 if (unlikely(ftrace_disabled))
2971 goto out_unlock;
2972
2973 do_for_each_ftrace_rec(pg, rec) {
2974 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2975 ret = enter_record(hash, rec, not);
2976 if (ret < 0) {
2977 found = ret;
2978 goto out_unlock;
2979 }
2980 found = 1;
2981 }
2982 } while_for_each_ftrace_rec();
2983 out_unlock:
2984 mutex_unlock(&ftrace_lock);
2985
2986 return found;
2987}
2988
2989static int
2990ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2991{
2992 return match_records(hash, buff, len, NULL, 0);
2993}
2994
2995static int
2996ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2997{
2998 int not = 0;
2999
3000 /* blank or '*' mean the same */
3001 if (strcmp(buff, "*") == 0)
3002 buff[0] = 0;
3003
3004 /* handle the case of 'dont filter this module' */
3005 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
3006 buff[0] = 0;
3007 not = 1;
3008 }
3009
3010 return match_records(hash, buff, strlen(buff), mod, not);
3011}
3012
3013/*
3014 * We register the module command as a template to show others how
3015 * to register the a command as well.
3016 */
3017
3018static int
3019ftrace_mod_callback(struct ftrace_hash *hash,
3020 char *func, char *cmd, char *param, int enable)
3021{
3022 char *mod;
3023 int ret = -EINVAL;
3024
3025 /*
3026 * cmd == 'mod' because we only registered this func
3027 * for the 'mod' ftrace_func_command.
3028 * But if you register one func with multiple commands,
3029 * you can tell which command was used by the cmd
3030 * parameter.
3031 */
3032
3033 /* we must have a module name */
3034 if (!param)
3035 return ret;
3036
3037 mod = strsep(¶m, ":");
3038 if (!strlen(mod))
3039 return ret;
3040
3041 ret = ftrace_match_module_records(hash, func, mod);
3042 if (!ret)
3043 ret = -EINVAL;
3044 if (ret < 0)
3045 return ret;
3046
3047 return 0;
3048}
3049
3050static struct ftrace_func_command ftrace_mod_cmd = {
3051 .name = "mod",
3052 .func = ftrace_mod_callback,
3053};
3054
3055static int __init ftrace_mod_cmd_init(void)
3056{
3057 return register_ftrace_command(&ftrace_mod_cmd);
3058}
3059core_initcall(ftrace_mod_cmd_init);
3060
3061static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3062 struct ftrace_ops *op, struct pt_regs *pt_regs)
3063{
3064 struct ftrace_func_probe *entry;
3065 struct hlist_head *hhd;
3066 unsigned long key;
3067
3068 key = hash_long(ip, FTRACE_HASH_BITS);
3069
3070 hhd = &ftrace_func_hash[key];
3071
3072 if (hlist_empty(hhd))
3073 return;
3074
3075 /*
3076 * Disable preemption for these calls to prevent a RCU grace
3077 * period. This syncs the hash iteration and freeing of items
3078 * on the hash. rcu_read_lock is too dangerous here.
3079 */
3080 preempt_disable_notrace();
3081 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3082 if (entry->ip == ip)
3083 entry->ops->func(ip, parent_ip, &entry->data);
3084 }
3085 preempt_enable_notrace();
3086}
3087
3088static struct ftrace_ops trace_probe_ops __read_mostly =
3089{
3090 .func = function_trace_probe_call,
3091 .flags = FTRACE_OPS_FL_INITIALIZED,
3092 INIT_REGEX_LOCK(trace_probe_ops)
3093};
3094
3095static int ftrace_probe_registered;
3096
3097static void __enable_ftrace_function_probe(void)
3098{
3099 int ret;
3100 int i;
3101
3102 if (ftrace_probe_registered) {
3103 /* still need to update the function call sites */
3104 if (ftrace_enabled)
3105 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3106 return;
3107 }
3108
3109 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3110 struct hlist_head *hhd = &ftrace_func_hash[i];
3111 if (hhd->first)
3112 break;
3113 }
3114 /* Nothing registered? */
3115 if (i == FTRACE_FUNC_HASHSIZE)
3116 return;
3117
3118 ret = ftrace_startup(&trace_probe_ops, 0);
3119
3120 ftrace_probe_registered = 1;
3121}
3122
3123static void __disable_ftrace_function_probe(void)
3124{
3125 int i;
3126
3127 if (!ftrace_probe_registered)
3128 return;
3129
3130 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3131 struct hlist_head *hhd = &ftrace_func_hash[i];
3132 if (hhd->first)
3133 return;
3134 }
3135
3136 /* no more funcs left */
3137 ftrace_shutdown(&trace_probe_ops, 0);
3138
3139 ftrace_probe_registered = 0;
3140}
3141
3142
3143static void ftrace_free_entry(struct ftrace_func_probe *entry)
3144{
3145 if (entry->ops->free)
3146 entry->ops->free(entry->ops, entry->ip, &entry->data);
3147 kfree(entry);
3148}
3149
3150int
3151register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3152 void *data)
3153{
3154 struct ftrace_func_probe *entry;
3155 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3156 struct ftrace_hash *hash;
3157 struct ftrace_page *pg;
3158 struct dyn_ftrace *rec;
3159 int type, len, not;
3160 unsigned long key;
3161 int count = 0;
3162 char *search;
3163 int ret;
3164
3165 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3166 len = strlen(search);
3167
3168 /* we do not support '!' for function probes */
3169 if (WARN_ON(not))
3170 return -EINVAL;
3171
3172 mutex_lock(&trace_probe_ops.regex_lock);
3173
3174 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3175 if (!hash) {
3176 count = -ENOMEM;
3177 goto out;
3178 }
3179
3180 if (unlikely(ftrace_disabled)) {
3181 count = -ENODEV;
3182 goto out;
3183 }
3184
3185 mutex_lock(&ftrace_lock);
3186
3187 do_for_each_ftrace_rec(pg, rec) {
3188
3189 if (!ftrace_match_record(rec, NULL, search, len, type))
3190 continue;
3191
3192 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3193 if (!entry) {
3194 /* If we did not process any, then return error */
3195 if (!count)
3196 count = -ENOMEM;
3197 goto out_unlock;
3198 }
3199
3200 count++;
3201
3202 entry->data = data;
3203
3204 /*
3205 * The caller might want to do something special
3206 * for each function we find. We call the callback
3207 * to give the caller an opportunity to do so.
3208 */
3209 if (ops->init) {
3210 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3211 /* caller does not like this func */
3212 kfree(entry);
3213 continue;
3214 }
3215 }
3216
3217 ret = enter_record(hash, rec, 0);
3218 if (ret < 0) {
3219 kfree(entry);
3220 count = ret;
3221 goto out_unlock;
3222 }
3223
3224 entry->ops = ops;
3225 entry->ip = rec->ip;
3226
3227 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3228 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3229
3230 } while_for_each_ftrace_rec();
3231
3232 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3233 if (ret < 0)
3234 count = ret;
3235
3236 __enable_ftrace_function_probe();
3237
3238 out_unlock:
3239 mutex_unlock(&ftrace_lock);
3240 out:
3241 mutex_unlock(&trace_probe_ops.regex_lock);
3242 free_ftrace_hash(hash);
3243
3244 return count;
3245}
3246
3247enum {
3248 PROBE_TEST_FUNC = 1,
3249 PROBE_TEST_DATA = 2
3250};
3251
3252static void
3253__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3254 void *data, int flags)
3255{
3256 struct ftrace_func_entry *rec_entry;
3257 struct ftrace_func_probe *entry;
3258 struct ftrace_func_probe *p;
3259 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3260 struct list_head free_list;
3261 struct ftrace_hash *hash;
3262 struct hlist_node *tmp;
3263 char str[KSYM_SYMBOL_LEN];
3264 int type = MATCH_FULL;
3265 int i, len = 0;
3266 char *search;
3267
3268 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3269 glob = NULL;
3270 else if (glob) {
3271 int not;
3272
3273 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3274 len = strlen(search);
3275
3276 /* we do not support '!' for function probes */
3277 if (WARN_ON(not))
3278 return;
3279 }
3280
3281 mutex_lock(&trace_probe_ops.regex_lock);
3282
3283 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3284 if (!hash)
3285 /* Hmm, should report this somehow */
3286 goto out_unlock;
3287
3288 INIT_LIST_HEAD(&free_list);
3289
3290 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3291 struct hlist_head *hhd = &ftrace_func_hash[i];
3292
3293 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3294
3295 /* break up if statements for readability */
3296 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3297 continue;
3298
3299 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3300 continue;
3301
3302 /* do this last, since it is the most expensive */
3303 if (glob) {
3304 kallsyms_lookup(entry->ip, NULL, NULL,
3305 NULL, str);
3306 if (!ftrace_match(str, glob, len, type))
3307 continue;
3308 }
3309
3310 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3311 /* It is possible more than one entry had this ip */
3312 if (rec_entry)
3313 free_hash_entry(hash, rec_entry);
3314
3315 hlist_del_rcu(&entry->node);
3316 list_add(&entry->free_list, &free_list);
3317 }
3318 }
3319 mutex_lock(&ftrace_lock);
3320 __disable_ftrace_function_probe();
3321 /*
3322 * Remove after the disable is called. Otherwise, if the last
3323 * probe is removed, a null hash means *all enabled*.
3324 */
3325 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3326 synchronize_sched();
3327 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3328 list_del(&entry->free_list);
3329 ftrace_free_entry(entry);
3330 }
3331 mutex_unlock(&ftrace_lock);
3332
3333 out_unlock:
3334 mutex_unlock(&trace_probe_ops.regex_lock);
3335 free_ftrace_hash(hash);
3336}
3337
3338void
3339unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3340 void *data)
3341{
3342 __unregister_ftrace_function_probe(glob, ops, data,
3343 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3344}
3345
3346void
3347unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3348{
3349 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3350}
3351
3352void unregister_ftrace_function_probe_all(char *glob)
3353{
3354 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3355}
3356
3357static LIST_HEAD(ftrace_commands);
3358static DEFINE_MUTEX(ftrace_cmd_mutex);
3359
3360/*
3361 * Currently we only register ftrace commands from __init, so mark this
3362 * __init too.
3363 */
3364__init int register_ftrace_command(struct ftrace_func_command *cmd)
3365{
3366 struct ftrace_func_command *p;
3367 int ret = 0;
3368
3369 mutex_lock(&ftrace_cmd_mutex);
3370 list_for_each_entry(p, &ftrace_commands, list) {
3371 if (strcmp(cmd->name, p->name) == 0) {
3372 ret = -EBUSY;
3373 goto out_unlock;
3374 }
3375 }
3376 list_add(&cmd->list, &ftrace_commands);
3377 out_unlock:
3378 mutex_unlock(&ftrace_cmd_mutex);
3379
3380 return ret;
3381}
3382
3383/*
3384 * Currently we only unregister ftrace commands from __init, so mark
3385 * this __init too.
3386 */
3387__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3388{
3389 struct ftrace_func_command *p, *n;
3390 int ret = -ENODEV;
3391
3392 mutex_lock(&ftrace_cmd_mutex);
3393 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3394 if (strcmp(cmd->name, p->name) == 0) {
3395 ret = 0;
3396 list_del_init(&p->list);
3397 goto out_unlock;
3398 }
3399 }
3400 out_unlock:
3401 mutex_unlock(&ftrace_cmd_mutex);
3402
3403 return ret;
3404}
3405
3406static int ftrace_process_regex(struct ftrace_hash *hash,
3407 char *buff, int len, int enable)
3408{
3409 char *func, *command, *next = buff;
3410 struct ftrace_func_command *p;
3411 int ret = -EINVAL;
3412
3413 func = strsep(&next, ":");
3414
3415 if (!next) {
3416 ret = ftrace_match_records(hash, func, len);
3417 if (!ret)
3418 ret = -EINVAL;
3419 if (ret < 0)
3420 return ret;
3421 return 0;
3422 }
3423
3424 /* command found */
3425
3426 command = strsep(&next, ":");
3427
3428 mutex_lock(&ftrace_cmd_mutex);
3429 list_for_each_entry(p, &ftrace_commands, list) {
3430 if (strcmp(p->name, command) == 0) {
3431 ret = p->func(hash, func, command, next, enable);
3432 goto out_unlock;
3433 }
3434 }
3435 out_unlock:
3436 mutex_unlock(&ftrace_cmd_mutex);
3437
3438 return ret;
3439}
3440
3441static ssize_t
3442ftrace_regex_write(struct file *file, const char __user *ubuf,
3443 size_t cnt, loff_t *ppos, int enable)
3444{
3445 struct ftrace_iterator *iter;
3446 struct trace_parser *parser;
3447 ssize_t ret, read;
3448
3449 if (!cnt)
3450 return 0;
3451
3452 if (file->f_mode & FMODE_READ) {
3453 struct seq_file *m = file->private_data;
3454 iter = m->private;
3455 } else
3456 iter = file->private_data;
3457
3458 if (unlikely(ftrace_disabled))
3459 return -ENODEV;
3460
3461 /* iter->hash is a local copy, so we don't need regex_lock */
3462
3463 parser = &iter->parser;
3464 read = trace_get_user(parser, ubuf, cnt, ppos);
3465
3466 if (read >= 0 && trace_parser_loaded(parser) &&
3467 !trace_parser_cont(parser)) {
3468 ret = ftrace_process_regex(iter->hash, parser->buffer,
3469 parser->idx, enable);
3470 trace_parser_clear(parser);
3471 if (ret < 0)
3472 goto out;
3473 }
3474
3475 ret = read;
3476 out:
3477 return ret;
3478}
3479
3480ssize_t
3481ftrace_filter_write(struct file *file, const char __user *ubuf,
3482 size_t cnt, loff_t *ppos)
3483{
3484 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3485}
3486
3487ssize_t
3488ftrace_notrace_write(struct file *file, const char __user *ubuf,
3489 size_t cnt, loff_t *ppos)
3490{
3491 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3492}
3493
3494static int
3495ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3496{
3497 struct ftrace_func_entry *entry;
3498
3499 if (!ftrace_location(ip))
3500 return -EINVAL;
3501
3502 if (remove) {
3503 entry = ftrace_lookup_ip(hash, ip);
3504 if (!entry)
3505 return -ENOENT;
3506 free_hash_entry(hash, entry);
3507 return 0;
3508 }
3509
3510 return add_hash_entry(hash, ip);
3511}
3512
3513static void ftrace_ops_update_code(struct ftrace_ops *ops)
3514{
3515 if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
3516 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3517}
3518
3519static int
3520ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3521 unsigned long ip, int remove, int reset, int enable)
3522{
3523 struct ftrace_hash **orig_hash;
3524 struct ftrace_hash *hash;
3525 int ret;
3526
3527 /* All global ops uses the global ops filters */
3528 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3529 ops = &global_ops;
3530
3531 if (unlikely(ftrace_disabled))
3532 return -ENODEV;
3533
3534 mutex_lock(&ops->regex_lock);
3535
3536 if (enable)
3537 orig_hash = &ops->filter_hash;
3538 else
3539 orig_hash = &ops->notrace_hash;
3540
3541 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3542 if (!hash) {
3543 ret = -ENOMEM;
3544 goto out_regex_unlock;
3545 }
3546
3547 if (reset)
3548 ftrace_filter_reset(hash);
3549 if (buf && !ftrace_match_records(hash, buf, len)) {
3550 ret = -EINVAL;
3551 goto out_regex_unlock;
3552 }
3553 if (ip) {
3554 ret = ftrace_match_addr(hash, ip, remove);
3555 if (ret < 0)
3556 goto out_regex_unlock;
3557 }
3558
3559 mutex_lock(&ftrace_lock);
3560 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3561 if (!ret)
3562 ftrace_ops_update_code(ops);
3563
3564 mutex_unlock(&ftrace_lock);
3565
3566 out_regex_unlock:
3567 mutex_unlock(&ops->regex_lock);
3568
3569 free_ftrace_hash(hash);
3570 return ret;
3571}
3572
3573static int
3574ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3575 int reset, int enable)
3576{
3577 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3578}
3579
3580/**
3581 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3582 * @ops - the ops to set the filter with
3583 * @ip - the address to add to or remove from the filter.
3584 * @remove - non zero to remove the ip from the filter
3585 * @reset - non zero to reset all filters before applying this filter.
3586 *
3587 * Filters denote which functions should be enabled when tracing is enabled
3588 * If @ip is NULL, it failes to update filter.
3589 */
3590int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3591 int remove, int reset)
3592{
3593 ftrace_ops_init(ops);
3594 return ftrace_set_addr(ops, ip, remove, reset, 1);
3595}
3596EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3597
3598static int
3599ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3600 int reset, int enable)
3601{
3602 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3603}
3604
3605/**
3606 * ftrace_set_filter - set a function to filter on in ftrace
3607 * @ops - the ops to set the filter with
3608 * @buf - the string that holds the function filter text.
3609 * @len - the length of the string.
3610 * @reset - non zero to reset all filters before applying this filter.
3611 *
3612 * Filters denote which functions should be enabled when tracing is enabled.
3613 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3614 */
3615int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3616 int len, int reset)
3617{
3618 ftrace_ops_init(ops);
3619 return ftrace_set_regex(ops, buf, len, reset, 1);
3620}
3621EXPORT_SYMBOL_GPL(ftrace_set_filter);
3622
3623/**
3624 * ftrace_set_notrace - set a function to not trace in ftrace
3625 * @ops - the ops to set the notrace filter with
3626 * @buf - the string that holds the function notrace text.
3627 * @len - the length of the string.
3628 * @reset - non zero to reset all filters before applying this filter.
3629 *
3630 * Notrace Filters denote which functions should not be enabled when tracing
3631 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3632 * for tracing.
3633 */
3634int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3635 int len, int reset)
3636{
3637 ftrace_ops_init(ops);
3638 return ftrace_set_regex(ops, buf, len, reset, 0);
3639}
3640EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3641/**
3642 * ftrace_set_filter - set a function to filter on in ftrace
3643 * @ops - the ops to set the filter with
3644 * @buf - the string that holds the function filter text.
3645 * @len - the length of the string.
3646 * @reset - non zero to reset all filters before applying this filter.
3647 *
3648 * Filters denote which functions should be enabled when tracing is enabled.
3649 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3650 */
3651void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3652{
3653 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3654}
3655EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3656
3657/**
3658 * ftrace_set_notrace - set a function to not trace in ftrace
3659 * @ops - the ops to set the notrace filter with
3660 * @buf - the string that holds the function notrace text.
3661 * @len - the length of the string.
3662 * @reset - non zero to reset all filters before applying this filter.
3663 *
3664 * Notrace Filters denote which functions should not be enabled when tracing
3665 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3666 * for tracing.
3667 */
3668void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3669{
3670 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3671}
3672EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3673
3674/*
3675 * command line interface to allow users to set filters on boot up.
3676 */
3677#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3678static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3679static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3680
3681/* Used by function selftest to not test if filter is set */
3682bool ftrace_filter_param __initdata;
3683
3684static int __init set_ftrace_notrace(char *str)
3685{
3686 ftrace_filter_param = true;
3687 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3688 return 1;
3689}
3690__setup("ftrace_notrace=", set_ftrace_notrace);
3691
3692static int __init set_ftrace_filter(char *str)
3693{
3694 ftrace_filter_param = true;
3695 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3696 return 1;
3697}
3698__setup("ftrace_filter=", set_ftrace_filter);
3699
3700#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3701static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3702static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
3703
3704static int __init set_graph_function(char *str)
3705{
3706 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3707 return 1;
3708}
3709__setup("ftrace_graph_filter=", set_graph_function);
3710
3711static void __init set_ftrace_early_graph(char *buf)
3712{
3713 int ret;
3714 char *func;
3715
3716 while (buf) {
3717 func = strsep(&buf, ",");
3718 /* we allow only one expression at a time */
3719 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3720 FTRACE_GRAPH_MAX_FUNCS, func);
3721 if (ret)
3722 printk(KERN_DEBUG "ftrace: function %s not "
3723 "traceable\n", func);
3724 }
3725}
3726#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3727
3728void __init
3729ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3730{
3731 char *func;
3732
3733 ftrace_ops_init(ops);
3734
3735 while (buf) {
3736 func = strsep(&buf, ",");
3737 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3738 }
3739}
3740
3741static void __init set_ftrace_early_filters(void)
3742{
3743 if (ftrace_filter_buf[0])
3744 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3745 if (ftrace_notrace_buf[0])
3746 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3747#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3748 if (ftrace_graph_buf[0])
3749 set_ftrace_early_graph(ftrace_graph_buf);
3750#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3751}
3752
3753int ftrace_regex_release(struct inode *inode, struct file *file)
3754{
3755 struct seq_file *m = (struct seq_file *)file->private_data;
3756 struct ftrace_iterator *iter;
3757 struct ftrace_hash **orig_hash;
3758 struct trace_parser *parser;
3759 int filter_hash;
3760 int ret;
3761
3762 if (file->f_mode & FMODE_READ) {
3763 iter = m->private;
3764 seq_release(inode, file);
3765 } else
3766 iter = file->private_data;
3767
3768 parser = &iter->parser;
3769 if (trace_parser_loaded(parser)) {
3770 parser->buffer[parser->idx] = 0;
3771 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3772 }
3773
3774 trace_parser_put(parser);
3775
3776 mutex_lock(&iter->ops->regex_lock);
3777
3778 if (file->f_mode & FMODE_WRITE) {
3779 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3780
3781 if (filter_hash)
3782 orig_hash = &iter->ops->filter_hash;
3783 else
3784 orig_hash = &iter->ops->notrace_hash;
3785
3786 mutex_lock(&ftrace_lock);
3787 ret = ftrace_hash_move(iter->ops, filter_hash,
3788 orig_hash, iter->hash);
3789 if (!ret)
3790 ftrace_ops_update_code(iter->ops);
3791
3792 mutex_unlock(&ftrace_lock);
3793 }
3794
3795 mutex_unlock(&iter->ops->regex_lock);
3796 free_ftrace_hash(iter->hash);
3797 kfree(iter);
3798
3799 return 0;
3800}
3801
3802static const struct file_operations ftrace_avail_fops = {
3803 .open = ftrace_avail_open,
3804 .read = seq_read,
3805 .llseek = seq_lseek,
3806 .release = seq_release_private,
3807};
3808
3809static const struct file_operations ftrace_enabled_fops = {
3810 .open = ftrace_enabled_open,
3811 .read = seq_read,
3812 .llseek = seq_lseek,
3813 .release = seq_release_private,
3814};
3815
3816static const struct file_operations ftrace_filter_fops = {
3817 .open = ftrace_filter_open,
3818 .read = seq_read,
3819 .write = ftrace_filter_write,
3820 .llseek = tracing_lseek,
3821 .release = ftrace_regex_release,
3822};
3823
3824static const struct file_operations ftrace_notrace_fops = {
3825 .open = ftrace_notrace_open,
3826 .read = seq_read,
3827 .write = ftrace_notrace_write,
3828 .llseek = tracing_lseek,
3829 .release = ftrace_regex_release,
3830};
3831
3832#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3833
3834static DEFINE_MUTEX(graph_lock);
3835
3836int ftrace_graph_count;
3837int ftrace_graph_notrace_count;
3838unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3839unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3840
3841struct ftrace_graph_data {
3842 unsigned long *table;
3843 size_t size;
3844 int *count;
3845 const struct seq_operations *seq_ops;
3846};
3847
3848static void *
3849__g_next(struct seq_file *m, loff_t *pos)
3850{
3851 struct ftrace_graph_data *fgd = m->private;
3852
3853 if (*pos >= *fgd->count)
3854 return NULL;
3855 return &fgd->table[*pos];
3856}
3857
3858static void *
3859g_next(struct seq_file *m, void *v, loff_t *pos)
3860{
3861 (*pos)++;
3862 return __g_next(m, pos);
3863}
3864
3865static void *g_start(struct seq_file *m, loff_t *pos)
3866{
3867 struct ftrace_graph_data *fgd = m->private;
3868
3869 mutex_lock(&graph_lock);
3870
3871 /* Nothing, tell g_show to print all functions are enabled */
3872 if (!*fgd->count && !*pos)
3873 return (void *)1;
3874
3875 return __g_next(m, pos);
3876}
3877
3878static void g_stop(struct seq_file *m, void *p)
3879{
3880 mutex_unlock(&graph_lock);
3881}
3882
3883static int g_show(struct seq_file *m, void *v)
3884{
3885 unsigned long *ptr = v;
3886
3887 if (!ptr)
3888 return 0;
3889
3890 if (ptr == (unsigned long *)1) {
3891 seq_printf(m, "#### all functions enabled ####\n");
3892 return 0;
3893 }
3894
3895 seq_printf(m, "%ps\n", (void *)*ptr);
3896
3897 return 0;
3898}
3899
3900static const struct seq_operations ftrace_graph_seq_ops = {
3901 .start = g_start,
3902 .next = g_next,
3903 .stop = g_stop,
3904 .show = g_show,
3905};
3906
3907static int
3908__ftrace_graph_open(struct inode *inode, struct file *file,
3909 struct ftrace_graph_data *fgd)
3910{
3911 int ret = 0;
3912
3913 mutex_lock(&graph_lock);
3914 if ((file->f_mode & FMODE_WRITE) &&
3915 (file->f_flags & O_TRUNC)) {
3916 *fgd->count = 0;
3917 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
3918 }
3919 mutex_unlock(&graph_lock);
3920
3921 if (file->f_mode & FMODE_READ) {
3922 ret = seq_open(file, fgd->seq_ops);
3923 if (!ret) {
3924 struct seq_file *m = file->private_data;
3925 m->private = fgd;
3926 }
3927 } else
3928 file->private_data = fgd;
3929
3930 return ret;
3931}
3932
3933static int
3934ftrace_graph_open(struct inode *inode, struct file *file)
3935{
3936 struct ftrace_graph_data *fgd;
3937
3938 if (unlikely(ftrace_disabled))
3939 return -ENODEV;
3940
3941 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3942 if (fgd == NULL)
3943 return -ENOMEM;
3944
3945 fgd->table = ftrace_graph_funcs;
3946 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3947 fgd->count = &ftrace_graph_count;
3948 fgd->seq_ops = &ftrace_graph_seq_ops;
3949
3950 return __ftrace_graph_open(inode, file, fgd);
3951}
3952
3953static int
3954ftrace_graph_notrace_open(struct inode *inode, struct file *file)
3955{
3956 struct ftrace_graph_data *fgd;
3957
3958 if (unlikely(ftrace_disabled))
3959 return -ENODEV;
3960
3961 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3962 if (fgd == NULL)
3963 return -ENOMEM;
3964
3965 fgd->table = ftrace_graph_notrace_funcs;
3966 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3967 fgd->count = &ftrace_graph_notrace_count;
3968 fgd->seq_ops = &ftrace_graph_seq_ops;
3969
3970 return __ftrace_graph_open(inode, file, fgd);
3971}
3972
3973static int
3974ftrace_graph_release(struct inode *inode, struct file *file)
3975{
3976 if (file->f_mode & FMODE_READ) {
3977 struct seq_file *m = file->private_data;
3978
3979 kfree(m->private);
3980 seq_release(inode, file);
3981 } else {
3982 kfree(file->private_data);
3983 }
3984
3985 return 0;
3986}
3987
3988static int
3989ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
3990{
3991 struct dyn_ftrace *rec;
3992 struct ftrace_page *pg;
3993 int search_len;
3994 int fail = 1;
3995 int type, not;
3996 char *search;
3997 bool exists;
3998 int i;
3999
4000 /* decode regex */
4001 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
4002 if (!not && *idx >= size)
4003 return -EBUSY;
4004
4005 search_len = strlen(search);
4006
4007 mutex_lock(&ftrace_lock);
4008
4009 if (unlikely(ftrace_disabled)) {
4010 mutex_unlock(&ftrace_lock);
4011 return -ENODEV;
4012 }
4013
4014 do_for_each_ftrace_rec(pg, rec) {
4015
4016 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
4017 /* if it is in the array */
4018 exists = false;
4019 for (i = 0; i < *idx; i++) {
4020 if (array[i] == rec->ip) {
4021 exists = true;
4022 break;
4023 }
4024 }
4025
4026 if (!not) {
4027 fail = 0;
4028 if (!exists) {
4029 array[(*idx)++] = rec->ip;
4030 if (*idx >= size)
4031 goto out;
4032 }
4033 } else {
4034 if (exists) {
4035 array[i] = array[--(*idx)];
4036 array[*idx] = 0;
4037 fail = 0;
4038 }
4039 }
4040 }
4041 } while_for_each_ftrace_rec();
4042out:
4043 mutex_unlock(&ftrace_lock);
4044
4045 if (fail)
4046 return -EINVAL;
4047
4048 return 0;
4049}
4050
4051static ssize_t
4052ftrace_graph_write(struct file *file, const char __user *ubuf,
4053 size_t cnt, loff_t *ppos)
4054{
4055 struct trace_parser parser;
4056 ssize_t read, ret = 0;
4057 struct ftrace_graph_data *fgd = file->private_data;
4058
4059 if (!cnt)
4060 return 0;
4061
4062 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4063 return -ENOMEM;
4064
4065 read = trace_get_user(&parser, ubuf, cnt, ppos);
4066
4067 if (read >= 0 && trace_parser_loaded((&parser))) {
4068 parser.buffer[parser.idx] = 0;
4069
4070 mutex_lock(&graph_lock);
4071
4072 /* we allow only one expression at a time */
4073 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4074 parser.buffer);
4075
4076 mutex_unlock(&graph_lock);
4077 }
4078
4079 if (!ret)
4080 ret = read;
4081
4082 trace_parser_put(&parser);
4083
4084 return ret;
4085}
4086
4087static const struct file_operations ftrace_graph_fops = {
4088 .open = ftrace_graph_open,
4089 .read = seq_read,
4090 .write = ftrace_graph_write,
4091 .llseek = tracing_lseek,
4092 .release = ftrace_graph_release,
4093};
4094
4095static const struct file_operations ftrace_graph_notrace_fops = {
4096 .open = ftrace_graph_notrace_open,
4097 .read = seq_read,
4098 .write = ftrace_graph_write,
4099 .llseek = tracing_lseek,
4100 .release = ftrace_graph_release,
4101};
4102#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4103
4104void ftrace_create_filter_files(struct ftrace_ops *ops,
4105 struct dentry *parent)
4106{
4107
4108 trace_create_file("set_ftrace_filter", 0644, parent,
4109 ops, &ftrace_filter_fops);
4110
4111 trace_create_file("set_ftrace_notrace", 0644, parent,
4112 ops, &ftrace_notrace_fops);
4113}
4114
4115/*
4116 * The name "destroy_filter_files" is really a misnomer. Although
4117 * in the future, it may actualy delete the files, but this is
4118 * really intended to make sure the ops passed in are disabled
4119 * and that when this function returns, the caller is free to
4120 * free the ops.
4121 *
4122 * The "destroy" name is only to match the "create" name that this
4123 * should be paired with.
4124 */
4125void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4126{
4127 mutex_lock(&ftrace_lock);
4128 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4129 ftrace_shutdown(ops, 0);
4130 ops->flags |= FTRACE_OPS_FL_DELETED;
4131 mutex_unlock(&ftrace_lock);
4132}
4133
4134static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
4135{
4136
4137 trace_create_file("available_filter_functions", 0444,
4138 d_tracer, NULL, &ftrace_avail_fops);
4139
4140 trace_create_file("enabled_functions", 0444,
4141 d_tracer, NULL, &ftrace_enabled_fops);
4142
4143 ftrace_create_filter_files(&global_ops, d_tracer);
4144
4145#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4146 trace_create_file("set_graph_function", 0444, d_tracer,
4147 NULL,
4148 &ftrace_graph_fops);
4149 trace_create_file("set_graph_notrace", 0444, d_tracer,
4150 NULL,
4151 &ftrace_graph_notrace_fops);
4152#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4153
4154 return 0;
4155}
4156
4157static int ftrace_cmp_ips(const void *a, const void *b)
4158{
4159 const unsigned long *ipa = a;
4160 const unsigned long *ipb = b;
4161
4162 if (*ipa > *ipb)
4163 return 1;
4164 if (*ipa < *ipb)
4165 return -1;
4166 return 0;
4167}
4168
4169static void ftrace_swap_ips(void *a, void *b, int size)
4170{
4171 unsigned long *ipa = a;
4172 unsigned long *ipb = b;
4173 unsigned long t;
4174
4175 t = *ipa;
4176 *ipa = *ipb;
4177 *ipb = t;
4178}
4179
4180static int ftrace_process_locs(struct module *mod,
4181 unsigned long *start,
4182 unsigned long *end)
4183{
4184 struct ftrace_page *start_pg;
4185 struct ftrace_page *pg;
4186 struct dyn_ftrace *rec;
4187 unsigned long count;
4188 unsigned long *p;
4189 unsigned long addr;
4190 unsigned long flags = 0; /* Shut up gcc */
4191 int ret = -ENOMEM;
4192
4193 count = end - start;
4194
4195 if (!count)
4196 return 0;
4197
4198 sort(start, count, sizeof(*start),
4199 ftrace_cmp_ips, ftrace_swap_ips);
4200
4201 start_pg = ftrace_allocate_pages(count);
4202 if (!start_pg)
4203 return -ENOMEM;
4204
4205 mutex_lock(&ftrace_lock);
4206
4207 /*
4208 * Core and each module needs their own pages, as
4209 * modules will free them when they are removed.
4210 * Force a new page to be allocated for modules.
4211 */
4212 if (!mod) {
4213 WARN_ON(ftrace_pages || ftrace_pages_start);
4214 /* First initialization */
4215 ftrace_pages = ftrace_pages_start = start_pg;
4216 } else {
4217 if (!ftrace_pages)
4218 goto out;
4219
4220 if (WARN_ON(ftrace_pages->next)) {
4221 /* Hmm, we have free pages? */
4222 while (ftrace_pages->next)
4223 ftrace_pages = ftrace_pages->next;
4224 }
4225
4226 ftrace_pages->next = start_pg;
4227 }
4228
4229 p = start;
4230 pg = start_pg;
4231 while (p < end) {
4232 addr = ftrace_call_adjust(*p++);
4233 /*
4234 * Some architecture linkers will pad between
4235 * the different mcount_loc sections of different
4236 * object files to satisfy alignments.
4237 * Skip any NULL pointers.
4238 */
4239 if (!addr)
4240 continue;
4241
4242 if (pg->index == pg->size) {
4243 /* We should have allocated enough */
4244 if (WARN_ON(!pg->next))
4245 break;
4246 pg = pg->next;
4247 }
4248
4249 rec = &pg->records[pg->index++];
4250 rec->ip = addr;
4251 }
4252
4253 /* We should have used all pages */
4254 WARN_ON(pg->next);
4255
4256 /* Assign the last page to ftrace_pages */
4257 ftrace_pages = pg;
4258
4259 /*
4260 * We only need to disable interrupts on start up
4261 * because we are modifying code that an interrupt
4262 * may execute, and the modification is not atomic.
4263 * But for modules, nothing runs the code we modify
4264 * until we are finished with it, and there's no
4265 * reason to cause large interrupt latencies while we do it.
4266 */
4267 if (!mod)
4268 local_irq_save(flags);
4269 ftrace_update_code(mod, start_pg);
4270 if (!mod)
4271 local_irq_restore(flags);
4272 ret = 0;
4273 out:
4274 mutex_unlock(&ftrace_lock);
4275
4276 return ret;
4277}
4278
4279#ifdef CONFIG_MODULES
4280
4281#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4282
4283void ftrace_release_mod(struct module *mod)
4284{
4285 struct dyn_ftrace *rec;
4286 struct ftrace_page **last_pg;
4287 struct ftrace_page *pg;
4288 int order;
4289
4290 mutex_lock(&ftrace_lock);
4291
4292 if (ftrace_disabled)
4293 goto out_unlock;
4294
4295 /*
4296 * Each module has its own ftrace_pages, remove
4297 * them from the list.
4298 */
4299 last_pg = &ftrace_pages_start;
4300 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4301 rec = &pg->records[0];
4302 if (within_module_core(rec->ip, mod)) {
4303 /*
4304 * As core pages are first, the first
4305 * page should never be a module page.
4306 */
4307 if (WARN_ON(pg == ftrace_pages_start))
4308 goto out_unlock;
4309
4310 /* Check if we are deleting the last page */
4311 if (pg == ftrace_pages)
4312 ftrace_pages = next_to_ftrace_page(last_pg);
4313
4314 *last_pg = pg->next;
4315 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4316 free_pages((unsigned long)pg->records, order);
4317 kfree(pg);
4318 } else
4319 last_pg = &pg->next;
4320 }
4321 out_unlock:
4322 mutex_unlock(&ftrace_lock);
4323}
4324
4325static void ftrace_init_module(struct module *mod,
4326 unsigned long *start, unsigned long *end)
4327{
4328 if (ftrace_disabled || start == end)
4329 return;
4330 ftrace_process_locs(mod, start, end);
4331}
4332
4333void ftrace_module_init(struct module *mod)
4334{
4335 ftrace_init_module(mod, mod->ftrace_callsites,
4336 mod->ftrace_callsites +
4337 mod->num_ftrace_callsites);
4338}
4339
4340static int ftrace_module_notify_exit(struct notifier_block *self,
4341 unsigned long val, void *data)
4342{
4343 struct module *mod = data;
4344
4345 if (val == MODULE_STATE_GOING)
4346 ftrace_release_mod(mod);
4347
4348 return 0;
4349}
4350#else
4351static int ftrace_module_notify_exit(struct notifier_block *self,
4352 unsigned long val, void *data)
4353{
4354 return 0;
4355}
4356#endif /* CONFIG_MODULES */
4357
4358struct notifier_block ftrace_module_exit_nb = {
4359 .notifier_call = ftrace_module_notify_exit,
4360 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4361};
4362
4363void __init ftrace_init(void)
4364{
4365 extern unsigned long __start_mcount_loc[];
4366 extern unsigned long __stop_mcount_loc[];
4367 unsigned long count, flags;
4368 int ret;
4369
4370 local_irq_save(flags);
4371 ret = ftrace_dyn_arch_init();
4372 local_irq_restore(flags);
4373 if (ret)
4374 goto failed;
4375
4376 count = __stop_mcount_loc - __start_mcount_loc;
4377 if (!count) {
4378 pr_info("ftrace: No functions to be traced?\n");
4379 goto failed;
4380 }
4381
4382 pr_info("ftrace: allocating %ld entries in %ld pages\n",
4383 count, count / ENTRIES_PER_PAGE + 1);
4384
4385 last_ftrace_enabled = ftrace_enabled = 1;
4386
4387 ret = ftrace_process_locs(NULL,
4388 __start_mcount_loc,
4389 __stop_mcount_loc);
4390
4391 ret = register_module_notifier(&ftrace_module_exit_nb);
4392 if (ret)
4393 pr_warning("Failed to register trace ftrace module exit notifier\n");
4394
4395 set_ftrace_early_filters();
4396
4397 return;
4398 failed:
4399 ftrace_disabled = 1;
4400}
4401
4402#else
4403
4404static struct ftrace_ops global_ops = {
4405 .func = ftrace_stub,
4406 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4407 INIT_REGEX_LOCK(global_ops)
4408};
4409
4410static int __init ftrace_nodyn_init(void)
4411{
4412 ftrace_enabled = 1;
4413 return 0;
4414}
4415core_initcall(ftrace_nodyn_init);
4416
4417static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4418static inline void ftrace_startup_enable(int command) { }
4419/* Keep as macros so we do not need to define the commands */
4420# define ftrace_startup(ops, command) \
4421 ({ \
4422 int ___ret = __register_ftrace_function(ops); \
4423 if (!___ret) \
4424 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4425 ___ret; \
4426 })
4427# define ftrace_shutdown(ops, command) \
4428 ({ \
4429 int ___ret = __unregister_ftrace_function(ops); \
4430 if (!___ret) \
4431 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
4432 ___ret; \
4433 })
4434
4435# define ftrace_startup_sysctl() do { } while (0)
4436# define ftrace_shutdown_sysctl() do { } while (0)
4437
4438static inline int
4439ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4440{
4441 return 1;
4442}
4443
4444#endif /* CONFIG_DYNAMIC_FTRACE */
4445
4446static void
4447ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4448 struct ftrace_ops *op, struct pt_regs *regs)
4449{
4450 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4451 return;
4452
4453 /*
4454 * Some of the ops may be dynamically allocated,
4455 * they must be freed after a synchronize_sched().
4456 */
4457 preempt_disable_notrace();
4458 trace_recursion_set(TRACE_CONTROL_BIT);
4459
4460 /*
4461 * Control funcs (perf) uses RCU. Only trace if
4462 * RCU is currently active.
4463 */
4464 if (!rcu_is_watching())
4465 goto out;
4466
4467 do_for_each_ftrace_op(op, ftrace_control_list) {
4468 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4469 !ftrace_function_local_disabled(op) &&
4470 ftrace_ops_test(op, ip, regs))
4471 op->func(ip, parent_ip, op, regs);
4472 } while_for_each_ftrace_op(op);
4473 out:
4474 trace_recursion_clear(TRACE_CONTROL_BIT);
4475 preempt_enable_notrace();
4476}
4477
4478static struct ftrace_ops control_ops = {
4479 .func = ftrace_ops_control_func,
4480 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4481 INIT_REGEX_LOCK(control_ops)
4482};
4483
4484static inline void
4485__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4486 struct ftrace_ops *ignored, struct pt_regs *regs)
4487{
4488 struct ftrace_ops *op;
4489 int bit;
4490
4491 if (function_trace_stop)
4492 return;
4493
4494 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4495 if (bit < 0)
4496 return;
4497
4498 /*
4499 * Some of the ops may be dynamically allocated,
4500 * they must be freed after a synchronize_sched().
4501 */
4502 preempt_disable_notrace();
4503 do_for_each_ftrace_op(op, ftrace_ops_list) {
4504 if (ftrace_ops_test(op, ip, regs))
4505 op->func(ip, parent_ip, op, regs);
4506 } while_for_each_ftrace_op(op);
4507 preempt_enable_notrace();
4508 trace_clear_recursion(bit);
4509}
4510
4511/*
4512 * Some archs only support passing ip and parent_ip. Even though
4513 * the list function ignores the op parameter, we do not want any
4514 * C side effects, where a function is called without the caller
4515 * sending a third parameter.
4516 * Archs are to support both the regs and ftrace_ops at the same time.
4517 * If they support ftrace_ops, it is assumed they support regs.
4518 * If call backs want to use regs, they must either check for regs
4519 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4520 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4521 * An architecture can pass partial regs with ftrace_ops and still
4522 * set the ARCH_SUPPORT_FTARCE_OPS.
4523 */
4524#if ARCH_SUPPORTS_FTRACE_OPS
4525static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4526 struct ftrace_ops *op, struct pt_regs *regs)
4527{
4528 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4529}
4530#else
4531static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4532{
4533 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4534}
4535#endif
4536
4537static void clear_ftrace_swapper(void)
4538{
4539 struct task_struct *p;
4540 int cpu;
4541
4542 get_online_cpus();
4543 for_each_online_cpu(cpu) {
4544 p = idle_task(cpu);
4545 clear_tsk_trace_trace(p);
4546 }
4547 put_online_cpus();
4548}
4549
4550static void set_ftrace_swapper(void)
4551{
4552 struct task_struct *p;
4553 int cpu;
4554
4555 get_online_cpus();
4556 for_each_online_cpu(cpu) {
4557 p = idle_task(cpu);
4558 set_tsk_trace_trace(p);
4559 }
4560 put_online_cpus();
4561}
4562
4563static void clear_ftrace_pid(struct pid *pid)
4564{
4565 struct task_struct *p;
4566
4567 rcu_read_lock();
4568 do_each_pid_task(pid, PIDTYPE_PID, p) {
4569 clear_tsk_trace_trace(p);
4570 } while_each_pid_task(pid, PIDTYPE_PID, p);
4571 rcu_read_unlock();
4572
4573 put_pid(pid);
4574}
4575
4576static void set_ftrace_pid(struct pid *pid)
4577{
4578 struct task_struct *p;
4579
4580 rcu_read_lock();
4581 do_each_pid_task(pid, PIDTYPE_PID, p) {
4582 set_tsk_trace_trace(p);
4583 } while_each_pid_task(pid, PIDTYPE_PID, p);
4584 rcu_read_unlock();
4585}
4586
4587static void clear_ftrace_pid_task(struct pid *pid)
4588{
4589 if (pid == ftrace_swapper_pid)
4590 clear_ftrace_swapper();
4591 else
4592 clear_ftrace_pid(pid);
4593}
4594
4595static void set_ftrace_pid_task(struct pid *pid)
4596{
4597 if (pid == ftrace_swapper_pid)
4598 set_ftrace_swapper();
4599 else
4600 set_ftrace_pid(pid);
4601}
4602
4603static int ftrace_pid_add(int p)
4604{
4605 struct pid *pid;
4606 struct ftrace_pid *fpid;
4607 int ret = -EINVAL;
4608
4609 mutex_lock(&ftrace_lock);
4610
4611 if (!p)
4612 pid = ftrace_swapper_pid;
4613 else
4614 pid = find_get_pid(p);
4615
4616 if (!pid)
4617 goto out;
4618
4619 ret = 0;
4620
4621 list_for_each_entry(fpid, &ftrace_pids, list)
4622 if (fpid->pid == pid)
4623 goto out_put;
4624
4625 ret = -ENOMEM;
4626
4627 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4628 if (!fpid)
4629 goto out_put;
4630
4631 list_add(&fpid->list, &ftrace_pids);
4632 fpid->pid = pid;
4633
4634 set_ftrace_pid_task(pid);
4635
4636 ftrace_update_pid_func();
4637 ftrace_startup_enable(0);
4638
4639 mutex_unlock(&ftrace_lock);
4640 return 0;
4641
4642out_put:
4643 if (pid != ftrace_swapper_pid)
4644 put_pid(pid);
4645
4646out:
4647 mutex_unlock(&ftrace_lock);
4648 return ret;
4649}
4650
4651static void ftrace_pid_reset(void)
4652{
4653 struct ftrace_pid *fpid, *safe;
4654
4655 mutex_lock(&ftrace_lock);
4656 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4657 struct pid *pid = fpid->pid;
4658
4659 clear_ftrace_pid_task(pid);
4660
4661 list_del(&fpid->list);
4662 kfree(fpid);
4663 }
4664
4665 ftrace_update_pid_func();
4666 ftrace_startup_enable(0);
4667
4668 mutex_unlock(&ftrace_lock);
4669}
4670
4671static void *fpid_start(struct seq_file *m, loff_t *pos)
4672{
4673 mutex_lock(&ftrace_lock);
4674
4675 if (list_empty(&ftrace_pids) && (!*pos))
4676 return (void *) 1;
4677
4678 return seq_list_start(&ftrace_pids, *pos);
4679}
4680
4681static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4682{
4683 if (v == (void *)1)
4684 return NULL;
4685
4686 return seq_list_next(v, &ftrace_pids, pos);
4687}
4688
4689static void fpid_stop(struct seq_file *m, void *p)
4690{
4691 mutex_unlock(&ftrace_lock);
4692}
4693
4694static int fpid_show(struct seq_file *m, void *v)
4695{
4696 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4697
4698 if (v == (void *)1) {
4699 seq_printf(m, "no pid\n");
4700 return 0;
4701 }
4702
4703 if (fpid->pid == ftrace_swapper_pid)
4704 seq_printf(m, "swapper tasks\n");
4705 else
4706 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4707
4708 return 0;
4709}
4710
4711static const struct seq_operations ftrace_pid_sops = {
4712 .start = fpid_start,
4713 .next = fpid_next,
4714 .stop = fpid_stop,
4715 .show = fpid_show,
4716};
4717
4718static int
4719ftrace_pid_open(struct inode *inode, struct file *file)
4720{
4721 int ret = 0;
4722
4723 if ((file->f_mode & FMODE_WRITE) &&
4724 (file->f_flags & O_TRUNC))
4725 ftrace_pid_reset();
4726
4727 if (file->f_mode & FMODE_READ)
4728 ret = seq_open(file, &ftrace_pid_sops);
4729
4730 return ret;
4731}
4732
4733static ssize_t
4734ftrace_pid_write(struct file *filp, const char __user *ubuf,
4735 size_t cnt, loff_t *ppos)
4736{
4737 char buf[64], *tmp;
4738 long val;
4739 int ret;
4740
4741 if (cnt >= sizeof(buf))
4742 return -EINVAL;
4743
4744 if (copy_from_user(&buf, ubuf, cnt))
4745 return -EFAULT;
4746
4747 buf[cnt] = 0;
4748
4749 /*
4750 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4751 * to clean the filter quietly.
4752 */
4753 tmp = strstrip(buf);
4754 if (strlen(tmp) == 0)
4755 return 1;
4756
4757 ret = kstrtol(tmp, 10, &val);
4758 if (ret < 0)
4759 return ret;
4760
4761 ret = ftrace_pid_add(val);
4762
4763 return ret ? ret : cnt;
4764}
4765
4766static int
4767ftrace_pid_release(struct inode *inode, struct file *file)
4768{
4769 if (file->f_mode & FMODE_READ)
4770 seq_release(inode, file);
4771
4772 return 0;
4773}
4774
4775static const struct file_operations ftrace_pid_fops = {
4776 .open = ftrace_pid_open,
4777 .write = ftrace_pid_write,
4778 .read = seq_read,
4779 .llseek = tracing_lseek,
4780 .release = ftrace_pid_release,
4781};
4782
4783static __init int ftrace_init_debugfs(void)
4784{
4785 struct dentry *d_tracer;
4786
4787 d_tracer = tracing_init_dentry();
4788 if (!d_tracer)
4789 return 0;
4790
4791 ftrace_init_dyn_debugfs(d_tracer);
4792
4793 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4794 NULL, &ftrace_pid_fops);
4795
4796 ftrace_profile_debugfs(d_tracer);
4797
4798 return 0;
4799}
4800fs_initcall(ftrace_init_debugfs);
4801
4802/**
4803 * ftrace_kill - kill ftrace
4804 *
4805 * This function should be used by panic code. It stops ftrace
4806 * but in a not so nice way. If you need to simply kill ftrace
4807 * from a non-atomic section, use ftrace_kill.
4808 */
4809void ftrace_kill(void)
4810{
4811 ftrace_disabled = 1;
4812 ftrace_enabled = 0;
4813 clear_ftrace_function();
4814}
4815
4816/**
4817 * Test if ftrace is dead or not.
4818 */
4819int ftrace_is_dead(void)
4820{
4821 return ftrace_disabled;
4822}
4823
4824/**
4825 * register_ftrace_function - register a function for profiling
4826 * @ops - ops structure that holds the function for profiling.
4827 *
4828 * Register a function to be called by all functions in the
4829 * kernel.
4830 *
4831 * Note: @ops->func and all the functions it calls must be labeled
4832 * with "notrace", otherwise it will go into a
4833 * recursive loop.
4834 */
4835int register_ftrace_function(struct ftrace_ops *ops)
4836{
4837 int ret = -1;
4838
4839 ftrace_ops_init(ops);
4840
4841 mutex_lock(&ftrace_lock);
4842
4843 ret = ftrace_startup(ops, 0);
4844
4845 mutex_unlock(&ftrace_lock);
4846
4847 return ret;
4848}
4849EXPORT_SYMBOL_GPL(register_ftrace_function);
4850
4851/**
4852 * unregister_ftrace_function - unregister a function for profiling.
4853 * @ops - ops structure that holds the function to unregister
4854 *
4855 * Unregister a function that was added to be called by ftrace profiling.
4856 */
4857int unregister_ftrace_function(struct ftrace_ops *ops)
4858{
4859 int ret;
4860
4861 mutex_lock(&ftrace_lock);
4862 ret = ftrace_shutdown(ops, 0);
4863 mutex_unlock(&ftrace_lock);
4864
4865 return ret;
4866}
4867EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4868
4869int
4870ftrace_enable_sysctl(struct ctl_table *table, int write,
4871 void __user *buffer, size_t *lenp,
4872 loff_t *ppos)
4873{
4874 int ret = -ENODEV;
4875
4876 mutex_lock(&ftrace_lock);
4877
4878 if (unlikely(ftrace_disabled))
4879 goto out;
4880
4881 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4882
4883 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4884 goto out;
4885
4886 last_ftrace_enabled = !!ftrace_enabled;
4887
4888 if (ftrace_enabled) {
4889
4890 ftrace_startup_sysctl();
4891
4892 /* we are starting ftrace again */
4893 if (ftrace_ops_list != &ftrace_list_end)
4894 update_ftrace_function();
4895
4896 } else {
4897 /* stopping ftrace calls (just send to ftrace_stub) */
4898 ftrace_trace_function = ftrace_stub;
4899
4900 ftrace_shutdown_sysctl();
4901 }
4902
4903 out:
4904 mutex_unlock(&ftrace_lock);
4905 return ret;
4906}
4907
4908#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4909
4910static int ftrace_graph_active;
4911static struct notifier_block ftrace_suspend_notifier;
4912
4913int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4914{
4915 return 0;
4916}
4917
4918/* The callbacks that hook a function */
4919trace_func_graph_ret_t ftrace_graph_return =
4920 (trace_func_graph_ret_t)ftrace_stub;
4921trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4922static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
4923
4924/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4925static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4926{
4927 int i;
4928 int ret = 0;
4929 unsigned long flags;
4930 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4931 struct task_struct *g, *t;
4932
4933 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4934 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4935 * sizeof(struct ftrace_ret_stack),
4936 GFP_KERNEL);
4937 if (!ret_stack_list[i]) {
4938 start = 0;
4939 end = i;
4940 ret = -ENOMEM;
4941 goto free;
4942 }
4943 }
4944
4945 read_lock_irqsave(&tasklist_lock, flags);
4946 do_each_thread(g, t) {
4947 if (start == end) {
4948 ret = -EAGAIN;
4949 goto unlock;
4950 }
4951
4952 if (t->ret_stack == NULL) {
4953 atomic_set(&t->tracing_graph_pause, 0);
4954 atomic_set(&t->trace_overrun, 0);
4955 t->curr_ret_stack = -1;
4956 /* Make sure the tasks see the -1 first: */
4957 smp_wmb();
4958 t->ret_stack = ret_stack_list[start++];
4959 }
4960 } while_each_thread(g, t);
4961
4962unlock:
4963 read_unlock_irqrestore(&tasklist_lock, flags);
4964free:
4965 for (i = start; i < end; i++)
4966 kfree(ret_stack_list[i]);
4967 return ret;
4968}
4969
4970static void
4971ftrace_graph_probe_sched_switch(void *ignore,
4972 struct task_struct *prev, struct task_struct *next)
4973{
4974 unsigned long long timestamp;
4975 int index;
4976
4977 /*
4978 * Does the user want to count the time a function was asleep.
4979 * If so, do not update the time stamps.
4980 */
4981 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4982 return;
4983
4984 timestamp = trace_clock_local();
4985
4986 prev->ftrace_timestamp = timestamp;
4987
4988 /* only process tasks that we timestamped */
4989 if (!next->ftrace_timestamp)
4990 return;
4991
4992 /*
4993 * Update all the counters in next to make up for the
4994 * time next was sleeping.
4995 */
4996 timestamp -= next->ftrace_timestamp;
4997
4998 for (index = next->curr_ret_stack; index >= 0; index--)
4999 next->ret_stack[index].calltime += timestamp;
5000}
5001
5002/* Allocate a return stack for each task */
5003static int start_graph_tracing(void)
5004{
5005 struct ftrace_ret_stack **ret_stack_list;
5006 int ret, cpu;
5007
5008 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5009 sizeof(struct ftrace_ret_stack *),
5010 GFP_KERNEL);
5011
5012 if (!ret_stack_list)
5013 return -ENOMEM;
5014
5015 /* The cpu_boot init_task->ret_stack will never be freed */
5016 for_each_online_cpu(cpu) {
5017 if (!idle_task(cpu)->ret_stack)
5018 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5019 }
5020
5021 do {
5022 ret = alloc_retstack_tasklist(ret_stack_list);
5023 } while (ret == -EAGAIN);
5024
5025 if (!ret) {
5026 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5027 if (ret)
5028 pr_info("ftrace_graph: Couldn't activate tracepoint"
5029 " probe to kernel_sched_switch\n");
5030 }
5031
5032 kfree(ret_stack_list);
5033 return ret;
5034}
5035
5036/*
5037 * Hibernation protection.
5038 * The state of the current task is too much unstable during
5039 * suspend/restore to disk. We want to protect against that.
5040 */
5041static int
5042ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5043 void *unused)
5044{
5045 switch (state) {
5046 case PM_HIBERNATION_PREPARE:
5047 pause_graph_tracing();
5048 break;
5049
5050 case PM_POST_HIBERNATION:
5051 unpause_graph_tracing();
5052 break;
5053 }
5054 return NOTIFY_DONE;
5055}
5056
5057/* Just a place holder for function graph */
5058static struct ftrace_ops fgraph_ops __read_mostly = {
5059 .func = ftrace_stub,
5060 .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL |
5061 FTRACE_OPS_FL_RECURSION_SAFE,
5062};
5063
5064static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5065{
5066 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5067 return 0;
5068 return __ftrace_graph_entry(trace);
5069}
5070
5071/*
5072 * The function graph tracer should only trace the functions defined
5073 * by set_ftrace_filter and set_ftrace_notrace. If another function
5074 * tracer ops is registered, the graph tracer requires testing the
5075 * function against the global ops, and not just trace any function
5076 * that any ftrace_ops registered.
5077 */
5078static void update_function_graph_func(void)
5079{
5080 if (ftrace_ops_list == &ftrace_list_end ||
5081 (ftrace_ops_list == &global_ops &&
5082 global_ops.next == &ftrace_list_end))
5083 ftrace_graph_entry = __ftrace_graph_entry;
5084 else
5085 ftrace_graph_entry = ftrace_graph_entry_test;
5086}
5087
5088int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5089 trace_func_graph_ent_t entryfunc)
5090{
5091 int ret = 0;
5092
5093 mutex_lock(&ftrace_lock);
5094
5095 /* we currently allow only one tracer registered at a time */
5096 if (ftrace_graph_active) {
5097 ret = -EBUSY;
5098 goto out;
5099 }
5100
5101 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
5102 register_pm_notifier(&ftrace_suspend_notifier);
5103
5104 ftrace_graph_active++;
5105 ret = start_graph_tracing();
5106 if (ret) {
5107 ftrace_graph_active--;
5108 goto out;
5109 }
5110
5111 ftrace_graph_return = retfunc;
5112
5113 /*
5114 * Update the indirect function to the entryfunc, and the
5115 * function that gets called to the entry_test first. Then
5116 * call the update fgraph entry function to determine if
5117 * the entryfunc should be called directly or not.
5118 */
5119 __ftrace_graph_entry = entryfunc;
5120 ftrace_graph_entry = ftrace_graph_entry_test;
5121 update_function_graph_func();
5122
5123 ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
5124
5125out:
5126 mutex_unlock(&ftrace_lock);
5127 return ret;
5128}
5129
5130void unregister_ftrace_graph(void)
5131{
5132 mutex_lock(&ftrace_lock);
5133
5134 if (unlikely(!ftrace_graph_active))
5135 goto out;
5136
5137 ftrace_graph_active--;
5138 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5139 ftrace_graph_entry = ftrace_graph_entry_stub;
5140 __ftrace_graph_entry = ftrace_graph_entry_stub;
5141 ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
5142 unregister_pm_notifier(&ftrace_suspend_notifier);
5143 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5144
5145 out:
5146 mutex_unlock(&ftrace_lock);
5147}
5148
5149static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5150
5151static void
5152graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5153{
5154 atomic_set(&t->tracing_graph_pause, 0);
5155 atomic_set(&t->trace_overrun, 0);
5156 t->ftrace_timestamp = 0;
5157 /* make curr_ret_stack visible before we add the ret_stack */
5158 smp_wmb();
5159 t->ret_stack = ret_stack;
5160}
5161
5162/*
5163 * Allocate a return stack for the idle task. May be the first
5164 * time through, or it may be done by CPU hotplug online.
5165 */
5166void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5167{
5168 t->curr_ret_stack = -1;
5169 /*
5170 * The idle task has no parent, it either has its own
5171 * stack or no stack at all.
5172 */
5173 if (t->ret_stack)
5174 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5175
5176 if (ftrace_graph_active) {
5177 struct ftrace_ret_stack *ret_stack;
5178
5179 ret_stack = per_cpu(idle_ret_stack, cpu);
5180 if (!ret_stack) {
5181 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5182 * sizeof(struct ftrace_ret_stack),
5183 GFP_KERNEL);
5184 if (!ret_stack)
5185 return;
5186 per_cpu(idle_ret_stack, cpu) = ret_stack;
5187 }
5188 graph_init_task(t, ret_stack);
5189 }
5190}
5191
5192/* Allocate a return stack for newly created task */
5193void ftrace_graph_init_task(struct task_struct *t)
5194{
5195 /* Make sure we do not use the parent ret_stack */
5196 t->ret_stack = NULL;
5197 t->curr_ret_stack = -1;
5198
5199 if (ftrace_graph_active) {
5200 struct ftrace_ret_stack *ret_stack;
5201
5202 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5203 * sizeof(struct ftrace_ret_stack),
5204 GFP_KERNEL);
5205 if (!ret_stack)
5206 return;
5207 graph_init_task(t, ret_stack);
5208 }
5209}
5210
5211void ftrace_graph_exit_task(struct task_struct *t)
5212{
5213 struct ftrace_ret_stack *ret_stack = t->ret_stack;
5214
5215 t->ret_stack = NULL;
5216 /* NULL must become visible to IRQs before we free it: */
5217 barrier();
5218
5219 kfree(ret_stack);
5220}
5221
5222void ftrace_graph_stop(void)
5223{
5224 ftrace_stop();
5225}
5226#endif