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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code in the latency_tracer, that is:
12 *
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
15 */
16
17#include <linux/stop_machine.h>
18#include <linux/clocksource.h>
19#include <linux/sched/task.h>
20#include <linux/kallsyms.h>
21#include <linux/security.h>
22#include <linux/seq_file.h>
23#include <linux/tracefs.h>
24#include <linux/hardirq.h>
25#include <linux/kthread.h>
26#include <linux/uaccess.h>
27#include <linux/bsearch.h>
28#include <linux/module.h>
29#include <linux/ftrace.h>
30#include <linux/sysctl.h>
31#include <linux/slab.h>
32#include <linux/ctype.h>
33#include <linux/sort.h>
34#include <linux/list.h>
35#include <linux/hash.h>
36#include <linux/rcupdate.h>
37#include <linux/kprobes.h>
38
39#include <trace/events/sched.h>
40
41#include <asm/sections.h>
42#include <asm/setup.h>
43
44#include "ftrace_internal.h"
45#include "trace_output.h"
46#include "trace_stat.h"
47
48#define FTRACE_WARN_ON(cond) \
49 ({ \
50 int ___r = cond; \
51 if (WARN_ON(___r)) \
52 ftrace_kill(); \
53 ___r; \
54 })
55
56#define FTRACE_WARN_ON_ONCE(cond) \
57 ({ \
58 int ___r = cond; \
59 if (WARN_ON_ONCE(___r)) \
60 ftrace_kill(); \
61 ___r; \
62 })
63
64/* hash bits for specific function selection */
65#define FTRACE_HASH_DEFAULT_BITS 10
66#define FTRACE_HASH_MAX_BITS 12
67
68#ifdef CONFIG_DYNAMIC_FTRACE
69#define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
72#else
73#define INIT_OPS_HASH(opsname)
74#endif
75
76enum {
77 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
79};
80
81struct ftrace_ops ftrace_list_end __read_mostly = {
82 .func = ftrace_stub,
83 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
84 INIT_OPS_HASH(ftrace_list_end)
85};
86
87/* ftrace_enabled is a method to turn ftrace on or off */
88int ftrace_enabled __read_mostly;
89static int last_ftrace_enabled;
90
91/* Current function tracing op */
92struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
93/* What to set function_trace_op to */
94static struct ftrace_ops *set_function_trace_op;
95
96static bool ftrace_pids_enabled(struct ftrace_ops *ops)
97{
98 struct trace_array *tr;
99
100 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
101 return false;
102
103 tr = ops->private;
104
105 return tr->function_pids != NULL || tr->function_no_pids != NULL;
106}
107
108static void ftrace_update_trampoline(struct ftrace_ops *ops);
109
110/*
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
113 */
114static int ftrace_disabled __read_mostly;
115
116DEFINE_MUTEX(ftrace_lock);
117
118struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
119ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
120struct ftrace_ops global_ops;
121
122#if ARCH_SUPPORTS_FTRACE_OPS
123static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
124 struct ftrace_ops *op, struct pt_regs *regs);
125#else
126/* See comment below, where ftrace_ops_list_func is defined */
127static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
128#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
129#endif
130
131static inline void ftrace_ops_init(struct ftrace_ops *ops)
132{
133#ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
135 mutex_init(&ops->local_hash.regex_lock);
136 ops->func_hash = &ops->local_hash;
137 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
138 }
139#endif
140}
141
142static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
143 struct ftrace_ops *op, struct pt_regs *regs)
144{
145 struct trace_array *tr = op->private;
146 int pid;
147
148 if (tr) {
149 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
150 if (pid == FTRACE_PID_IGNORE)
151 return;
152 if (pid != FTRACE_PID_TRACE &&
153 pid != current->pid)
154 return;
155 }
156
157 op->saved_func(ip, parent_ip, op, regs);
158}
159
160static void ftrace_sync_ipi(void *data)
161{
162 /* Probably not needed, but do it anyway */
163 smp_rmb();
164}
165
166static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
167{
168 /*
169 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
170 * then it needs to call the list anyway.
171 */
172 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
173 FTRACE_FORCE_LIST_FUNC)
174 return ftrace_ops_list_func;
175
176 return ftrace_ops_get_func(ops);
177}
178
179static void update_ftrace_function(void)
180{
181 ftrace_func_t func;
182
183 /*
184 * Prepare the ftrace_ops that the arch callback will use.
185 * If there's only one ftrace_ops registered, the ftrace_ops_list
186 * will point to the ops we want.
187 */
188 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
189 lockdep_is_held(&ftrace_lock));
190
191 /* If there's no ftrace_ops registered, just call the stub function */
192 if (set_function_trace_op == &ftrace_list_end) {
193 func = ftrace_stub;
194
195 /*
196 * If we are at the end of the list and this ops is
197 * recursion safe and not dynamic and the arch supports passing ops,
198 * then have the mcount trampoline call the function directly.
199 */
200 } else if (rcu_dereference_protected(ftrace_ops_list->next,
201 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
202 func = ftrace_ops_get_list_func(ftrace_ops_list);
203
204 } else {
205 /* Just use the default ftrace_ops */
206 set_function_trace_op = &ftrace_list_end;
207 func = ftrace_ops_list_func;
208 }
209
210 update_function_graph_func();
211
212 /* If there's no change, then do nothing more here */
213 if (ftrace_trace_function == func)
214 return;
215
216 /*
217 * If we are using the list function, it doesn't care
218 * about the function_trace_ops.
219 */
220 if (func == ftrace_ops_list_func) {
221 ftrace_trace_function = func;
222 /*
223 * Don't even bother setting function_trace_ops,
224 * it would be racy to do so anyway.
225 */
226 return;
227 }
228
229#ifndef CONFIG_DYNAMIC_FTRACE
230 /*
231 * For static tracing, we need to be a bit more careful.
232 * The function change takes affect immediately. Thus,
233 * we need to coorditate the setting of the function_trace_ops
234 * with the setting of the ftrace_trace_function.
235 *
236 * Set the function to the list ops, which will call the
237 * function we want, albeit indirectly, but it handles the
238 * ftrace_ops and doesn't depend on function_trace_op.
239 */
240 ftrace_trace_function = ftrace_ops_list_func;
241 /*
242 * Make sure all CPUs see this. Yes this is slow, but static
243 * tracing is slow and nasty to have enabled.
244 */
245 synchronize_rcu_tasks_rude();
246 /* Now all cpus are using the list ops. */
247 function_trace_op = set_function_trace_op;
248 /* Make sure the function_trace_op is visible on all CPUs */
249 smp_wmb();
250 /* Nasty way to force a rmb on all cpus */
251 smp_call_function(ftrace_sync_ipi, NULL, 1);
252 /* OK, we are all set to update the ftrace_trace_function now! */
253#endif /* !CONFIG_DYNAMIC_FTRACE */
254
255 ftrace_trace_function = func;
256}
257
258static void add_ftrace_ops(struct ftrace_ops __rcu **list,
259 struct ftrace_ops *ops)
260{
261 rcu_assign_pointer(ops->next, *list);
262
263 /*
264 * We are entering ops into the list but another
265 * CPU might be walking that list. We need to make sure
266 * the ops->next pointer is valid before another CPU sees
267 * the ops pointer included into the list.
268 */
269 rcu_assign_pointer(*list, ops);
270}
271
272static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
273 struct ftrace_ops *ops)
274{
275 struct ftrace_ops **p;
276
277 /*
278 * If we are removing the last function, then simply point
279 * to the ftrace_stub.
280 */
281 if (rcu_dereference_protected(*list,
282 lockdep_is_held(&ftrace_lock)) == ops &&
283 rcu_dereference_protected(ops->next,
284 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
285 *list = &ftrace_list_end;
286 return 0;
287 }
288
289 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
290 if (*p == ops)
291 break;
292
293 if (*p != ops)
294 return -1;
295
296 *p = (*p)->next;
297 return 0;
298}
299
300static void ftrace_update_trampoline(struct ftrace_ops *ops);
301
302int __register_ftrace_function(struct ftrace_ops *ops)
303{
304 if (ops->flags & FTRACE_OPS_FL_DELETED)
305 return -EINVAL;
306
307 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
308 return -EBUSY;
309
310#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
311 /*
312 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
313 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
314 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
315 */
316 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
317 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
318 return -EINVAL;
319
320 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
321 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
322#endif
323 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
324 return -EBUSY;
325
326 if (!core_kernel_data((unsigned long)ops))
327 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
328
329 add_ftrace_ops(&ftrace_ops_list, ops);
330
331 /* Always save the function, and reset at unregistering */
332 ops->saved_func = ops->func;
333
334 if (ftrace_pids_enabled(ops))
335 ops->func = ftrace_pid_func;
336
337 ftrace_update_trampoline(ops);
338
339 if (ftrace_enabled)
340 update_ftrace_function();
341
342 return 0;
343}
344
345int __unregister_ftrace_function(struct ftrace_ops *ops)
346{
347 int ret;
348
349 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
350 return -EBUSY;
351
352 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
353
354 if (ret < 0)
355 return ret;
356
357 if (ftrace_enabled)
358 update_ftrace_function();
359
360 ops->func = ops->saved_func;
361
362 return 0;
363}
364
365static void ftrace_update_pid_func(void)
366{
367 struct ftrace_ops *op;
368
369 /* Only do something if we are tracing something */
370 if (ftrace_trace_function == ftrace_stub)
371 return;
372
373 do_for_each_ftrace_op(op, ftrace_ops_list) {
374 if (op->flags & FTRACE_OPS_FL_PID) {
375 op->func = ftrace_pids_enabled(op) ?
376 ftrace_pid_func : op->saved_func;
377 ftrace_update_trampoline(op);
378 }
379 } while_for_each_ftrace_op(op);
380
381 update_ftrace_function();
382}
383
384#ifdef CONFIG_FUNCTION_PROFILER
385struct ftrace_profile {
386 struct hlist_node node;
387 unsigned long ip;
388 unsigned long counter;
389#ifdef CONFIG_FUNCTION_GRAPH_TRACER
390 unsigned long long time;
391 unsigned long long time_squared;
392#endif
393};
394
395struct ftrace_profile_page {
396 struct ftrace_profile_page *next;
397 unsigned long index;
398 struct ftrace_profile records[];
399};
400
401struct ftrace_profile_stat {
402 atomic_t disabled;
403 struct hlist_head *hash;
404 struct ftrace_profile_page *pages;
405 struct ftrace_profile_page *start;
406 struct tracer_stat stat;
407};
408
409#define PROFILE_RECORDS_SIZE \
410 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
411
412#define PROFILES_PER_PAGE \
413 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
414
415static int ftrace_profile_enabled __read_mostly;
416
417/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
418static DEFINE_MUTEX(ftrace_profile_lock);
419
420static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
421
422#define FTRACE_PROFILE_HASH_BITS 10
423#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
424
425static void *
426function_stat_next(void *v, int idx)
427{
428 struct ftrace_profile *rec = v;
429 struct ftrace_profile_page *pg;
430
431 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
432
433 again:
434 if (idx != 0)
435 rec++;
436
437 if ((void *)rec >= (void *)&pg->records[pg->index]) {
438 pg = pg->next;
439 if (!pg)
440 return NULL;
441 rec = &pg->records[0];
442 if (!rec->counter)
443 goto again;
444 }
445
446 return rec;
447}
448
449static void *function_stat_start(struct tracer_stat *trace)
450{
451 struct ftrace_profile_stat *stat =
452 container_of(trace, struct ftrace_profile_stat, stat);
453
454 if (!stat || !stat->start)
455 return NULL;
456
457 return function_stat_next(&stat->start->records[0], 0);
458}
459
460#ifdef CONFIG_FUNCTION_GRAPH_TRACER
461/* function graph compares on total time */
462static int function_stat_cmp(const void *p1, const void *p2)
463{
464 const struct ftrace_profile *a = p1;
465 const struct ftrace_profile *b = p2;
466
467 if (a->time < b->time)
468 return -1;
469 if (a->time > b->time)
470 return 1;
471 else
472 return 0;
473}
474#else
475/* not function graph compares against hits */
476static int function_stat_cmp(const void *p1, const void *p2)
477{
478 const struct ftrace_profile *a = p1;
479 const struct ftrace_profile *b = p2;
480
481 if (a->counter < b->counter)
482 return -1;
483 if (a->counter > b->counter)
484 return 1;
485 else
486 return 0;
487}
488#endif
489
490static int function_stat_headers(struct seq_file *m)
491{
492#ifdef CONFIG_FUNCTION_GRAPH_TRACER
493 seq_puts(m, " Function "
494 "Hit Time Avg s^2\n"
495 " -------- "
496 "--- ---- --- ---\n");
497#else
498 seq_puts(m, " Function Hit\n"
499 " -------- ---\n");
500#endif
501 return 0;
502}
503
504static int function_stat_show(struct seq_file *m, void *v)
505{
506 struct ftrace_profile *rec = v;
507 char str[KSYM_SYMBOL_LEN];
508 int ret = 0;
509#ifdef CONFIG_FUNCTION_GRAPH_TRACER
510 static struct trace_seq s;
511 unsigned long long avg;
512 unsigned long long stddev;
513#endif
514 mutex_lock(&ftrace_profile_lock);
515
516 /* we raced with function_profile_reset() */
517 if (unlikely(rec->counter == 0)) {
518 ret = -EBUSY;
519 goto out;
520 }
521
522#ifdef CONFIG_FUNCTION_GRAPH_TRACER
523 avg = div64_ul(rec->time, rec->counter);
524 if (tracing_thresh && (avg < tracing_thresh))
525 goto out;
526#endif
527
528 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
529 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
530
531#ifdef CONFIG_FUNCTION_GRAPH_TRACER
532 seq_puts(m, " ");
533
534 /* Sample standard deviation (s^2) */
535 if (rec->counter <= 1)
536 stddev = 0;
537 else {
538 /*
539 * Apply Welford's method:
540 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
541 */
542 stddev = rec->counter * rec->time_squared -
543 rec->time * rec->time;
544
545 /*
546 * Divide only 1000 for ns^2 -> us^2 conversion.
547 * trace_print_graph_duration will divide 1000 again.
548 */
549 stddev = div64_ul(stddev,
550 rec->counter * (rec->counter - 1) * 1000);
551 }
552
553 trace_seq_init(&s);
554 trace_print_graph_duration(rec->time, &s);
555 trace_seq_puts(&s, " ");
556 trace_print_graph_duration(avg, &s);
557 trace_seq_puts(&s, " ");
558 trace_print_graph_duration(stddev, &s);
559 trace_print_seq(m, &s);
560#endif
561 seq_putc(m, '\n');
562out:
563 mutex_unlock(&ftrace_profile_lock);
564
565 return ret;
566}
567
568static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
569{
570 struct ftrace_profile_page *pg;
571
572 pg = stat->pages = stat->start;
573
574 while (pg) {
575 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
576 pg->index = 0;
577 pg = pg->next;
578 }
579
580 memset(stat->hash, 0,
581 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
582}
583
584int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
585{
586 struct ftrace_profile_page *pg;
587 int functions;
588 int pages;
589 int i;
590
591 /* If we already allocated, do nothing */
592 if (stat->pages)
593 return 0;
594
595 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
596 if (!stat->pages)
597 return -ENOMEM;
598
599#ifdef CONFIG_DYNAMIC_FTRACE
600 functions = ftrace_update_tot_cnt;
601#else
602 /*
603 * We do not know the number of functions that exist because
604 * dynamic tracing is what counts them. With past experience
605 * we have around 20K functions. That should be more than enough.
606 * It is highly unlikely we will execute every function in
607 * the kernel.
608 */
609 functions = 20000;
610#endif
611
612 pg = stat->start = stat->pages;
613
614 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
615
616 for (i = 1; i < pages; i++) {
617 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
618 if (!pg->next)
619 goto out_free;
620 pg = pg->next;
621 }
622
623 return 0;
624
625 out_free:
626 pg = stat->start;
627 while (pg) {
628 unsigned long tmp = (unsigned long)pg;
629
630 pg = pg->next;
631 free_page(tmp);
632 }
633
634 stat->pages = NULL;
635 stat->start = NULL;
636
637 return -ENOMEM;
638}
639
640static int ftrace_profile_init_cpu(int cpu)
641{
642 struct ftrace_profile_stat *stat;
643 int size;
644
645 stat = &per_cpu(ftrace_profile_stats, cpu);
646
647 if (stat->hash) {
648 /* If the profile is already created, simply reset it */
649 ftrace_profile_reset(stat);
650 return 0;
651 }
652
653 /*
654 * We are profiling all functions, but usually only a few thousand
655 * functions are hit. We'll make a hash of 1024 items.
656 */
657 size = FTRACE_PROFILE_HASH_SIZE;
658
659 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
660
661 if (!stat->hash)
662 return -ENOMEM;
663
664 /* Preallocate the function profiling pages */
665 if (ftrace_profile_pages_init(stat) < 0) {
666 kfree(stat->hash);
667 stat->hash = NULL;
668 return -ENOMEM;
669 }
670
671 return 0;
672}
673
674static int ftrace_profile_init(void)
675{
676 int cpu;
677 int ret = 0;
678
679 for_each_possible_cpu(cpu) {
680 ret = ftrace_profile_init_cpu(cpu);
681 if (ret)
682 break;
683 }
684
685 return ret;
686}
687
688/* interrupts must be disabled */
689static struct ftrace_profile *
690ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
691{
692 struct ftrace_profile *rec;
693 struct hlist_head *hhd;
694 unsigned long key;
695
696 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
697 hhd = &stat->hash[key];
698
699 if (hlist_empty(hhd))
700 return NULL;
701
702 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
703 if (rec->ip == ip)
704 return rec;
705 }
706
707 return NULL;
708}
709
710static void ftrace_add_profile(struct ftrace_profile_stat *stat,
711 struct ftrace_profile *rec)
712{
713 unsigned long key;
714
715 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
716 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
717}
718
719/*
720 * The memory is already allocated, this simply finds a new record to use.
721 */
722static struct ftrace_profile *
723ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
724{
725 struct ftrace_profile *rec = NULL;
726
727 /* prevent recursion (from NMIs) */
728 if (atomic_inc_return(&stat->disabled) != 1)
729 goto out;
730
731 /*
732 * Try to find the function again since an NMI
733 * could have added it
734 */
735 rec = ftrace_find_profiled_func(stat, ip);
736 if (rec)
737 goto out;
738
739 if (stat->pages->index == PROFILES_PER_PAGE) {
740 if (!stat->pages->next)
741 goto out;
742 stat->pages = stat->pages->next;
743 }
744
745 rec = &stat->pages->records[stat->pages->index++];
746 rec->ip = ip;
747 ftrace_add_profile(stat, rec);
748
749 out:
750 atomic_dec(&stat->disabled);
751
752 return rec;
753}
754
755static void
756function_profile_call(unsigned long ip, unsigned long parent_ip,
757 struct ftrace_ops *ops, struct pt_regs *regs)
758{
759 struct ftrace_profile_stat *stat;
760 struct ftrace_profile *rec;
761 unsigned long flags;
762
763 if (!ftrace_profile_enabled)
764 return;
765
766 local_irq_save(flags);
767
768 stat = this_cpu_ptr(&ftrace_profile_stats);
769 if (!stat->hash || !ftrace_profile_enabled)
770 goto out;
771
772 rec = ftrace_find_profiled_func(stat, ip);
773 if (!rec) {
774 rec = ftrace_profile_alloc(stat, ip);
775 if (!rec)
776 goto out;
777 }
778
779 rec->counter++;
780 out:
781 local_irq_restore(flags);
782}
783
784#ifdef CONFIG_FUNCTION_GRAPH_TRACER
785static bool fgraph_graph_time = true;
786
787void ftrace_graph_graph_time_control(bool enable)
788{
789 fgraph_graph_time = enable;
790}
791
792static int profile_graph_entry(struct ftrace_graph_ent *trace)
793{
794 struct ftrace_ret_stack *ret_stack;
795
796 function_profile_call(trace->func, 0, NULL, NULL);
797
798 /* If function graph is shutting down, ret_stack can be NULL */
799 if (!current->ret_stack)
800 return 0;
801
802 ret_stack = ftrace_graph_get_ret_stack(current, 0);
803 if (ret_stack)
804 ret_stack->subtime = 0;
805
806 return 1;
807}
808
809static void profile_graph_return(struct ftrace_graph_ret *trace)
810{
811 struct ftrace_ret_stack *ret_stack;
812 struct ftrace_profile_stat *stat;
813 unsigned long long calltime;
814 struct ftrace_profile *rec;
815 unsigned long flags;
816
817 local_irq_save(flags);
818 stat = this_cpu_ptr(&ftrace_profile_stats);
819 if (!stat->hash || !ftrace_profile_enabled)
820 goto out;
821
822 /* If the calltime was zero'd ignore it */
823 if (!trace->calltime)
824 goto out;
825
826 calltime = trace->rettime - trace->calltime;
827
828 if (!fgraph_graph_time) {
829
830 /* Append this call time to the parent time to subtract */
831 ret_stack = ftrace_graph_get_ret_stack(current, 1);
832 if (ret_stack)
833 ret_stack->subtime += calltime;
834
835 ret_stack = ftrace_graph_get_ret_stack(current, 0);
836 if (ret_stack && ret_stack->subtime < calltime)
837 calltime -= ret_stack->subtime;
838 else
839 calltime = 0;
840 }
841
842 rec = ftrace_find_profiled_func(stat, trace->func);
843 if (rec) {
844 rec->time += calltime;
845 rec->time_squared += calltime * calltime;
846 }
847
848 out:
849 local_irq_restore(flags);
850}
851
852static struct fgraph_ops fprofiler_ops = {
853 .entryfunc = &profile_graph_entry,
854 .retfunc = &profile_graph_return,
855};
856
857static int register_ftrace_profiler(void)
858{
859 return register_ftrace_graph(&fprofiler_ops);
860}
861
862static void unregister_ftrace_profiler(void)
863{
864 unregister_ftrace_graph(&fprofiler_ops);
865}
866#else
867static struct ftrace_ops ftrace_profile_ops __read_mostly = {
868 .func = function_profile_call,
869 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
870 INIT_OPS_HASH(ftrace_profile_ops)
871};
872
873static int register_ftrace_profiler(void)
874{
875 return register_ftrace_function(&ftrace_profile_ops);
876}
877
878static void unregister_ftrace_profiler(void)
879{
880 unregister_ftrace_function(&ftrace_profile_ops);
881}
882#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
883
884static ssize_t
885ftrace_profile_write(struct file *filp, const char __user *ubuf,
886 size_t cnt, loff_t *ppos)
887{
888 unsigned long val;
889 int ret;
890
891 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
892 if (ret)
893 return ret;
894
895 val = !!val;
896
897 mutex_lock(&ftrace_profile_lock);
898 if (ftrace_profile_enabled ^ val) {
899 if (val) {
900 ret = ftrace_profile_init();
901 if (ret < 0) {
902 cnt = ret;
903 goto out;
904 }
905
906 ret = register_ftrace_profiler();
907 if (ret < 0) {
908 cnt = ret;
909 goto out;
910 }
911 ftrace_profile_enabled = 1;
912 } else {
913 ftrace_profile_enabled = 0;
914 /*
915 * unregister_ftrace_profiler calls stop_machine
916 * so this acts like an synchronize_rcu.
917 */
918 unregister_ftrace_profiler();
919 }
920 }
921 out:
922 mutex_unlock(&ftrace_profile_lock);
923
924 *ppos += cnt;
925
926 return cnt;
927}
928
929static ssize_t
930ftrace_profile_read(struct file *filp, char __user *ubuf,
931 size_t cnt, loff_t *ppos)
932{
933 char buf[64]; /* big enough to hold a number */
934 int r;
935
936 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
937 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
938}
939
940static const struct file_operations ftrace_profile_fops = {
941 .open = tracing_open_generic,
942 .read = ftrace_profile_read,
943 .write = ftrace_profile_write,
944 .llseek = default_llseek,
945};
946
947/* used to initialize the real stat files */
948static struct tracer_stat function_stats __initdata = {
949 .name = "functions",
950 .stat_start = function_stat_start,
951 .stat_next = function_stat_next,
952 .stat_cmp = function_stat_cmp,
953 .stat_headers = function_stat_headers,
954 .stat_show = function_stat_show
955};
956
957static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
958{
959 struct ftrace_profile_stat *stat;
960 struct dentry *entry;
961 char *name;
962 int ret;
963 int cpu;
964
965 for_each_possible_cpu(cpu) {
966 stat = &per_cpu(ftrace_profile_stats, cpu);
967
968 name = kasprintf(GFP_KERNEL, "function%d", cpu);
969 if (!name) {
970 /*
971 * The files created are permanent, if something happens
972 * we still do not free memory.
973 */
974 WARN(1,
975 "Could not allocate stat file for cpu %d\n",
976 cpu);
977 return;
978 }
979 stat->stat = function_stats;
980 stat->stat.name = name;
981 ret = register_stat_tracer(&stat->stat);
982 if (ret) {
983 WARN(1,
984 "Could not register function stat for cpu %d\n",
985 cpu);
986 kfree(name);
987 return;
988 }
989 }
990
991 entry = tracefs_create_file("function_profile_enabled", 0644,
992 d_tracer, NULL, &ftrace_profile_fops);
993 if (!entry)
994 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
995}
996
997#else /* CONFIG_FUNCTION_PROFILER */
998static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
999{
1000}
1001#endif /* CONFIG_FUNCTION_PROFILER */
1002
1003#ifdef CONFIG_DYNAMIC_FTRACE
1004
1005static struct ftrace_ops *removed_ops;
1006
1007/*
1008 * Set when doing a global update, like enabling all recs or disabling them.
1009 * It is not set when just updating a single ftrace_ops.
1010 */
1011static bool update_all_ops;
1012
1013#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1014# error Dynamic ftrace depends on MCOUNT_RECORD
1015#endif
1016
1017struct ftrace_func_probe {
1018 struct ftrace_probe_ops *probe_ops;
1019 struct ftrace_ops ops;
1020 struct trace_array *tr;
1021 struct list_head list;
1022 void *data;
1023 int ref;
1024};
1025
1026/*
1027 * We make these constant because no one should touch them,
1028 * but they are used as the default "empty hash", to avoid allocating
1029 * it all the time. These are in a read only section such that if
1030 * anyone does try to modify it, it will cause an exception.
1031 */
1032static const struct hlist_head empty_buckets[1];
1033static const struct ftrace_hash empty_hash = {
1034 .buckets = (struct hlist_head *)empty_buckets,
1035};
1036#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1037
1038struct ftrace_ops global_ops = {
1039 .func = ftrace_stub,
1040 .local_hash.notrace_hash = EMPTY_HASH,
1041 .local_hash.filter_hash = EMPTY_HASH,
1042 INIT_OPS_HASH(global_ops)
1043 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1044 FTRACE_OPS_FL_INITIALIZED |
1045 FTRACE_OPS_FL_PID,
1046};
1047
1048/*
1049 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1050 */
1051struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1052{
1053 struct ftrace_ops *op = NULL;
1054
1055 /*
1056 * Some of the ops may be dynamically allocated,
1057 * they are freed after a synchronize_rcu().
1058 */
1059 preempt_disable_notrace();
1060
1061 do_for_each_ftrace_op(op, ftrace_ops_list) {
1062 /*
1063 * This is to check for dynamically allocated trampolines.
1064 * Trampolines that are in kernel text will have
1065 * core_kernel_text() return true.
1066 */
1067 if (op->trampoline && op->trampoline_size)
1068 if (addr >= op->trampoline &&
1069 addr < op->trampoline + op->trampoline_size) {
1070 preempt_enable_notrace();
1071 return op;
1072 }
1073 } while_for_each_ftrace_op(op);
1074 preempt_enable_notrace();
1075
1076 return NULL;
1077}
1078
1079/*
1080 * This is used by __kernel_text_address() to return true if the
1081 * address is on a dynamically allocated trampoline that would
1082 * not return true for either core_kernel_text() or
1083 * is_module_text_address().
1084 */
1085bool is_ftrace_trampoline(unsigned long addr)
1086{
1087 return ftrace_ops_trampoline(addr) != NULL;
1088}
1089
1090struct ftrace_page {
1091 struct ftrace_page *next;
1092 struct dyn_ftrace *records;
1093 int index;
1094 int size;
1095};
1096
1097#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1098#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1099
1100static struct ftrace_page *ftrace_pages_start;
1101static struct ftrace_page *ftrace_pages;
1102
1103static __always_inline unsigned long
1104ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1105{
1106 if (hash->size_bits > 0)
1107 return hash_long(ip, hash->size_bits);
1108
1109 return 0;
1110}
1111
1112/* Only use this function if ftrace_hash_empty() has already been tested */
1113static __always_inline struct ftrace_func_entry *
1114__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1115{
1116 unsigned long key;
1117 struct ftrace_func_entry *entry;
1118 struct hlist_head *hhd;
1119
1120 key = ftrace_hash_key(hash, ip);
1121 hhd = &hash->buckets[key];
1122
1123 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1124 if (entry->ip == ip)
1125 return entry;
1126 }
1127 return NULL;
1128}
1129
1130/**
1131 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1132 * @hash: The hash to look at
1133 * @ip: The instruction pointer to test
1134 *
1135 * Search a given @hash to see if a given instruction pointer (@ip)
1136 * exists in it.
1137 *
1138 * Returns the entry that holds the @ip if found. NULL otherwise.
1139 */
1140struct ftrace_func_entry *
1141ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1142{
1143 if (ftrace_hash_empty(hash))
1144 return NULL;
1145
1146 return __ftrace_lookup_ip(hash, ip);
1147}
1148
1149static void __add_hash_entry(struct ftrace_hash *hash,
1150 struct ftrace_func_entry *entry)
1151{
1152 struct hlist_head *hhd;
1153 unsigned long key;
1154
1155 key = ftrace_hash_key(hash, entry->ip);
1156 hhd = &hash->buckets[key];
1157 hlist_add_head(&entry->hlist, hhd);
1158 hash->count++;
1159}
1160
1161static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1162{
1163 struct ftrace_func_entry *entry;
1164
1165 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1166 if (!entry)
1167 return -ENOMEM;
1168
1169 entry->ip = ip;
1170 __add_hash_entry(hash, entry);
1171
1172 return 0;
1173}
1174
1175static void
1176free_hash_entry(struct ftrace_hash *hash,
1177 struct ftrace_func_entry *entry)
1178{
1179 hlist_del(&entry->hlist);
1180 kfree(entry);
1181 hash->count--;
1182}
1183
1184static void
1185remove_hash_entry(struct ftrace_hash *hash,
1186 struct ftrace_func_entry *entry)
1187{
1188 hlist_del_rcu(&entry->hlist);
1189 hash->count--;
1190}
1191
1192static void ftrace_hash_clear(struct ftrace_hash *hash)
1193{
1194 struct hlist_head *hhd;
1195 struct hlist_node *tn;
1196 struct ftrace_func_entry *entry;
1197 int size = 1 << hash->size_bits;
1198 int i;
1199
1200 if (!hash->count)
1201 return;
1202
1203 for (i = 0; i < size; i++) {
1204 hhd = &hash->buckets[i];
1205 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1206 free_hash_entry(hash, entry);
1207 }
1208 FTRACE_WARN_ON(hash->count);
1209}
1210
1211static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1212{
1213 list_del(&ftrace_mod->list);
1214 kfree(ftrace_mod->module);
1215 kfree(ftrace_mod->func);
1216 kfree(ftrace_mod);
1217}
1218
1219static void clear_ftrace_mod_list(struct list_head *head)
1220{
1221 struct ftrace_mod_load *p, *n;
1222
1223 /* stack tracer isn't supported yet */
1224 if (!head)
1225 return;
1226
1227 mutex_lock(&ftrace_lock);
1228 list_for_each_entry_safe(p, n, head, list)
1229 free_ftrace_mod(p);
1230 mutex_unlock(&ftrace_lock);
1231}
1232
1233static void free_ftrace_hash(struct ftrace_hash *hash)
1234{
1235 if (!hash || hash == EMPTY_HASH)
1236 return;
1237 ftrace_hash_clear(hash);
1238 kfree(hash->buckets);
1239 kfree(hash);
1240}
1241
1242static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1243{
1244 struct ftrace_hash *hash;
1245
1246 hash = container_of(rcu, struct ftrace_hash, rcu);
1247 free_ftrace_hash(hash);
1248}
1249
1250static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1251{
1252 if (!hash || hash == EMPTY_HASH)
1253 return;
1254 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1255}
1256
1257void ftrace_free_filter(struct ftrace_ops *ops)
1258{
1259 ftrace_ops_init(ops);
1260 free_ftrace_hash(ops->func_hash->filter_hash);
1261 free_ftrace_hash(ops->func_hash->notrace_hash);
1262}
1263
1264static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1265{
1266 struct ftrace_hash *hash;
1267 int size;
1268
1269 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1270 if (!hash)
1271 return NULL;
1272
1273 size = 1 << size_bits;
1274 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1275
1276 if (!hash->buckets) {
1277 kfree(hash);
1278 return NULL;
1279 }
1280
1281 hash->size_bits = size_bits;
1282
1283 return hash;
1284}
1285
1286
1287static int ftrace_add_mod(struct trace_array *tr,
1288 const char *func, const char *module,
1289 int enable)
1290{
1291 struct ftrace_mod_load *ftrace_mod;
1292 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1293
1294 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1295 if (!ftrace_mod)
1296 return -ENOMEM;
1297
1298 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1299 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1300 ftrace_mod->enable = enable;
1301
1302 if (!ftrace_mod->func || !ftrace_mod->module)
1303 goto out_free;
1304
1305 list_add(&ftrace_mod->list, mod_head);
1306
1307 return 0;
1308
1309 out_free:
1310 free_ftrace_mod(ftrace_mod);
1311
1312 return -ENOMEM;
1313}
1314
1315static struct ftrace_hash *
1316alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1317{
1318 struct ftrace_func_entry *entry;
1319 struct ftrace_hash *new_hash;
1320 int size;
1321 int ret;
1322 int i;
1323
1324 new_hash = alloc_ftrace_hash(size_bits);
1325 if (!new_hash)
1326 return NULL;
1327
1328 if (hash)
1329 new_hash->flags = hash->flags;
1330
1331 /* Empty hash? */
1332 if (ftrace_hash_empty(hash))
1333 return new_hash;
1334
1335 size = 1 << hash->size_bits;
1336 for (i = 0; i < size; i++) {
1337 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1338 ret = add_hash_entry(new_hash, entry->ip);
1339 if (ret < 0)
1340 goto free_hash;
1341 }
1342 }
1343
1344 FTRACE_WARN_ON(new_hash->count != hash->count);
1345
1346 return new_hash;
1347
1348 free_hash:
1349 free_ftrace_hash(new_hash);
1350 return NULL;
1351}
1352
1353static void
1354ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1355static void
1356ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1357
1358static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1359 struct ftrace_hash *new_hash);
1360
1361static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1362{
1363 struct ftrace_func_entry *entry;
1364 struct ftrace_hash *new_hash;
1365 struct hlist_head *hhd;
1366 struct hlist_node *tn;
1367 int bits = 0;
1368 int i;
1369
1370 /*
1371 * Make the hash size about 1/2 the # found
1372 */
1373 for (size /= 2; size; size >>= 1)
1374 bits++;
1375
1376 /* Don't allocate too much */
1377 if (bits > FTRACE_HASH_MAX_BITS)
1378 bits = FTRACE_HASH_MAX_BITS;
1379
1380 new_hash = alloc_ftrace_hash(bits);
1381 if (!new_hash)
1382 return NULL;
1383
1384 new_hash->flags = src->flags;
1385
1386 size = 1 << src->size_bits;
1387 for (i = 0; i < size; i++) {
1388 hhd = &src->buckets[i];
1389 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1390 remove_hash_entry(src, entry);
1391 __add_hash_entry(new_hash, entry);
1392 }
1393 }
1394 return new_hash;
1395}
1396
1397static struct ftrace_hash *
1398__ftrace_hash_move(struct ftrace_hash *src)
1399{
1400 int size = src->count;
1401
1402 /*
1403 * If the new source is empty, just return the empty_hash.
1404 */
1405 if (ftrace_hash_empty(src))
1406 return EMPTY_HASH;
1407
1408 return dup_hash(src, size);
1409}
1410
1411static int
1412ftrace_hash_move(struct ftrace_ops *ops, int enable,
1413 struct ftrace_hash **dst, struct ftrace_hash *src)
1414{
1415 struct ftrace_hash *new_hash;
1416 int ret;
1417
1418 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1419 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1420 return -EINVAL;
1421
1422 new_hash = __ftrace_hash_move(src);
1423 if (!new_hash)
1424 return -ENOMEM;
1425
1426 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1427 if (enable) {
1428 /* IPMODIFY should be updated only when filter_hash updating */
1429 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1430 if (ret < 0) {
1431 free_ftrace_hash(new_hash);
1432 return ret;
1433 }
1434 }
1435
1436 /*
1437 * Remove the current set, update the hash and add
1438 * them back.
1439 */
1440 ftrace_hash_rec_disable_modify(ops, enable);
1441
1442 rcu_assign_pointer(*dst, new_hash);
1443
1444 ftrace_hash_rec_enable_modify(ops, enable);
1445
1446 return 0;
1447}
1448
1449static bool hash_contains_ip(unsigned long ip,
1450 struct ftrace_ops_hash *hash)
1451{
1452 /*
1453 * The function record is a match if it exists in the filter
1454 * hash and not in the notrace hash. Note, an emty hash is
1455 * considered a match for the filter hash, but an empty
1456 * notrace hash is considered not in the notrace hash.
1457 */
1458 return (ftrace_hash_empty(hash->filter_hash) ||
1459 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1460 (ftrace_hash_empty(hash->notrace_hash) ||
1461 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1462}
1463
1464/*
1465 * Test the hashes for this ops to see if we want to call
1466 * the ops->func or not.
1467 *
1468 * It's a match if the ip is in the ops->filter_hash or
1469 * the filter_hash does not exist or is empty,
1470 * AND
1471 * the ip is not in the ops->notrace_hash.
1472 *
1473 * This needs to be called with preemption disabled as
1474 * the hashes are freed with call_rcu().
1475 */
1476int
1477ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1478{
1479 struct ftrace_ops_hash hash;
1480 int ret;
1481
1482#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1483 /*
1484 * There's a small race when adding ops that the ftrace handler
1485 * that wants regs, may be called without them. We can not
1486 * allow that handler to be called if regs is NULL.
1487 */
1488 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1489 return 0;
1490#endif
1491
1492 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1493 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1494
1495 if (hash_contains_ip(ip, &hash))
1496 ret = 1;
1497 else
1498 ret = 0;
1499
1500 return ret;
1501}
1502
1503/*
1504 * This is a double for. Do not use 'break' to break out of the loop,
1505 * you must use a goto.
1506 */
1507#define do_for_each_ftrace_rec(pg, rec) \
1508 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1509 int _____i; \
1510 for (_____i = 0; _____i < pg->index; _____i++) { \
1511 rec = &pg->records[_____i];
1512
1513#define while_for_each_ftrace_rec() \
1514 } \
1515 }
1516
1517
1518static int ftrace_cmp_recs(const void *a, const void *b)
1519{
1520 const struct dyn_ftrace *key = a;
1521 const struct dyn_ftrace *rec = b;
1522
1523 if (key->flags < rec->ip)
1524 return -1;
1525 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1526 return 1;
1527 return 0;
1528}
1529
1530static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1531{
1532 struct ftrace_page *pg;
1533 struct dyn_ftrace *rec = NULL;
1534 struct dyn_ftrace key;
1535
1536 key.ip = start;
1537 key.flags = end; /* overload flags, as it is unsigned long */
1538
1539 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1540 if (end < pg->records[0].ip ||
1541 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1542 continue;
1543 rec = bsearch(&key, pg->records, pg->index,
1544 sizeof(struct dyn_ftrace),
1545 ftrace_cmp_recs);
1546 if (rec)
1547 break;
1548 }
1549 return rec;
1550}
1551
1552/**
1553 * ftrace_location_range - return the first address of a traced location
1554 * if it touches the given ip range
1555 * @start: start of range to search.
1556 * @end: end of range to search (inclusive). @end points to the last byte
1557 * to check.
1558 *
1559 * Returns rec->ip if the related ftrace location is a least partly within
1560 * the given address range. That is, the first address of the instruction
1561 * that is either a NOP or call to the function tracer. It checks the ftrace
1562 * internal tables to determine if the address belongs or not.
1563 */
1564unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1565{
1566 struct dyn_ftrace *rec;
1567
1568 rec = lookup_rec(start, end);
1569 if (rec)
1570 return rec->ip;
1571
1572 return 0;
1573}
1574
1575/**
1576 * ftrace_location - return true if the ip giving is a traced location
1577 * @ip: the instruction pointer to check
1578 *
1579 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1580 * That is, the instruction that is either a NOP or call to
1581 * the function tracer. It checks the ftrace internal tables to
1582 * determine if the address belongs or not.
1583 */
1584unsigned long ftrace_location(unsigned long ip)
1585{
1586 return ftrace_location_range(ip, ip);
1587}
1588
1589/**
1590 * ftrace_text_reserved - return true if range contains an ftrace location
1591 * @start: start of range to search
1592 * @end: end of range to search (inclusive). @end points to the last byte to check.
1593 *
1594 * Returns 1 if @start and @end contains a ftrace location.
1595 * That is, the instruction that is either a NOP or call to
1596 * the function tracer. It checks the ftrace internal tables to
1597 * determine if the address belongs or not.
1598 */
1599int ftrace_text_reserved(const void *start, const void *end)
1600{
1601 unsigned long ret;
1602
1603 ret = ftrace_location_range((unsigned long)start,
1604 (unsigned long)end);
1605
1606 return (int)!!ret;
1607}
1608
1609/* Test if ops registered to this rec needs regs */
1610static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1611{
1612 struct ftrace_ops *ops;
1613 bool keep_regs = false;
1614
1615 for (ops = ftrace_ops_list;
1616 ops != &ftrace_list_end; ops = ops->next) {
1617 /* pass rec in as regs to have non-NULL val */
1618 if (ftrace_ops_test(ops, rec->ip, rec)) {
1619 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1620 keep_regs = true;
1621 break;
1622 }
1623 }
1624 }
1625
1626 return keep_regs;
1627}
1628
1629static struct ftrace_ops *
1630ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1631static struct ftrace_ops *
1632ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1633
1634static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1635 int filter_hash,
1636 bool inc)
1637{
1638 struct ftrace_hash *hash;
1639 struct ftrace_hash *other_hash;
1640 struct ftrace_page *pg;
1641 struct dyn_ftrace *rec;
1642 bool update = false;
1643 int count = 0;
1644 int all = false;
1645
1646 /* Only update if the ops has been registered */
1647 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1648 return false;
1649
1650 /*
1651 * In the filter_hash case:
1652 * If the count is zero, we update all records.
1653 * Otherwise we just update the items in the hash.
1654 *
1655 * In the notrace_hash case:
1656 * We enable the update in the hash.
1657 * As disabling notrace means enabling the tracing,
1658 * and enabling notrace means disabling, the inc variable
1659 * gets inversed.
1660 */
1661 if (filter_hash) {
1662 hash = ops->func_hash->filter_hash;
1663 other_hash = ops->func_hash->notrace_hash;
1664 if (ftrace_hash_empty(hash))
1665 all = true;
1666 } else {
1667 inc = !inc;
1668 hash = ops->func_hash->notrace_hash;
1669 other_hash = ops->func_hash->filter_hash;
1670 /*
1671 * If the notrace hash has no items,
1672 * then there's nothing to do.
1673 */
1674 if (ftrace_hash_empty(hash))
1675 return false;
1676 }
1677
1678 do_for_each_ftrace_rec(pg, rec) {
1679 int in_other_hash = 0;
1680 int in_hash = 0;
1681 int match = 0;
1682
1683 if (rec->flags & FTRACE_FL_DISABLED)
1684 continue;
1685
1686 if (all) {
1687 /*
1688 * Only the filter_hash affects all records.
1689 * Update if the record is not in the notrace hash.
1690 */
1691 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1692 match = 1;
1693 } else {
1694 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1695 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1696
1697 /*
1698 * If filter_hash is set, we want to match all functions
1699 * that are in the hash but not in the other hash.
1700 *
1701 * If filter_hash is not set, then we are decrementing.
1702 * That means we match anything that is in the hash
1703 * and also in the other_hash. That is, we need to turn
1704 * off functions in the other hash because they are disabled
1705 * by this hash.
1706 */
1707 if (filter_hash && in_hash && !in_other_hash)
1708 match = 1;
1709 else if (!filter_hash && in_hash &&
1710 (in_other_hash || ftrace_hash_empty(other_hash)))
1711 match = 1;
1712 }
1713 if (!match)
1714 continue;
1715
1716 if (inc) {
1717 rec->flags++;
1718 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1719 return false;
1720
1721 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1722 rec->flags |= FTRACE_FL_DIRECT;
1723
1724 /*
1725 * If there's only a single callback registered to a
1726 * function, and the ops has a trampoline registered
1727 * for it, then we can call it directly.
1728 */
1729 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1730 rec->flags |= FTRACE_FL_TRAMP;
1731 else
1732 /*
1733 * If we are adding another function callback
1734 * to this function, and the previous had a
1735 * custom trampoline in use, then we need to go
1736 * back to the default trampoline.
1737 */
1738 rec->flags &= ~FTRACE_FL_TRAMP;
1739
1740 /*
1741 * If any ops wants regs saved for this function
1742 * then all ops will get saved regs.
1743 */
1744 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1745 rec->flags |= FTRACE_FL_REGS;
1746 } else {
1747 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1748 return false;
1749 rec->flags--;
1750
1751 /*
1752 * Only the internal direct_ops should have the
1753 * DIRECT flag set. Thus, if it is removing a
1754 * function, then that function should no longer
1755 * be direct.
1756 */
1757 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1758 rec->flags &= ~FTRACE_FL_DIRECT;
1759
1760 /*
1761 * If the rec had REGS enabled and the ops that is
1762 * being removed had REGS set, then see if there is
1763 * still any ops for this record that wants regs.
1764 * If not, we can stop recording them.
1765 */
1766 if (ftrace_rec_count(rec) > 0 &&
1767 rec->flags & FTRACE_FL_REGS &&
1768 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1769 if (!test_rec_ops_needs_regs(rec))
1770 rec->flags &= ~FTRACE_FL_REGS;
1771 }
1772
1773 /*
1774 * The TRAMP needs to be set only if rec count
1775 * is decremented to one, and the ops that is
1776 * left has a trampoline. As TRAMP can only be
1777 * enabled if there is only a single ops attached
1778 * to it.
1779 */
1780 if (ftrace_rec_count(rec) == 1 &&
1781 ftrace_find_tramp_ops_any(rec))
1782 rec->flags |= FTRACE_FL_TRAMP;
1783 else
1784 rec->flags &= ~FTRACE_FL_TRAMP;
1785
1786 /*
1787 * flags will be cleared in ftrace_check_record()
1788 * if rec count is zero.
1789 */
1790 }
1791 count++;
1792
1793 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1794 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1795
1796 /* Shortcut, if we handled all records, we are done. */
1797 if (!all && count == hash->count)
1798 return update;
1799 } while_for_each_ftrace_rec();
1800
1801 return update;
1802}
1803
1804static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1805 int filter_hash)
1806{
1807 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1808}
1809
1810static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1811 int filter_hash)
1812{
1813 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1814}
1815
1816static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1817 int filter_hash, int inc)
1818{
1819 struct ftrace_ops *op;
1820
1821 __ftrace_hash_rec_update(ops, filter_hash, inc);
1822
1823 if (ops->func_hash != &global_ops.local_hash)
1824 return;
1825
1826 /*
1827 * If the ops shares the global_ops hash, then we need to update
1828 * all ops that are enabled and use this hash.
1829 */
1830 do_for_each_ftrace_op(op, ftrace_ops_list) {
1831 /* Already done */
1832 if (op == ops)
1833 continue;
1834 if (op->func_hash == &global_ops.local_hash)
1835 __ftrace_hash_rec_update(op, filter_hash, inc);
1836 } while_for_each_ftrace_op(op);
1837}
1838
1839static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1840 int filter_hash)
1841{
1842 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1843}
1844
1845static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1846 int filter_hash)
1847{
1848 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1849}
1850
1851/*
1852 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1853 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1854 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1855 * Note that old_hash and new_hash has below meanings
1856 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1857 * - If the hash is EMPTY_HASH, it hits nothing
1858 * - Anything else hits the recs which match the hash entries.
1859 */
1860static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1861 struct ftrace_hash *old_hash,
1862 struct ftrace_hash *new_hash)
1863{
1864 struct ftrace_page *pg;
1865 struct dyn_ftrace *rec, *end = NULL;
1866 int in_old, in_new;
1867
1868 /* Only update if the ops has been registered */
1869 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1870 return 0;
1871
1872 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1873 return 0;
1874
1875 /*
1876 * Since the IPMODIFY is a very address sensitive action, we do not
1877 * allow ftrace_ops to set all functions to new hash.
1878 */
1879 if (!new_hash || !old_hash)
1880 return -EINVAL;
1881
1882 /* Update rec->flags */
1883 do_for_each_ftrace_rec(pg, rec) {
1884
1885 if (rec->flags & FTRACE_FL_DISABLED)
1886 continue;
1887
1888 /* We need to update only differences of filter_hash */
1889 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1890 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1891 if (in_old == in_new)
1892 continue;
1893
1894 if (in_new) {
1895 /* New entries must ensure no others are using it */
1896 if (rec->flags & FTRACE_FL_IPMODIFY)
1897 goto rollback;
1898 rec->flags |= FTRACE_FL_IPMODIFY;
1899 } else /* Removed entry */
1900 rec->flags &= ~FTRACE_FL_IPMODIFY;
1901 } while_for_each_ftrace_rec();
1902
1903 return 0;
1904
1905rollback:
1906 end = rec;
1907
1908 /* Roll back what we did above */
1909 do_for_each_ftrace_rec(pg, rec) {
1910
1911 if (rec->flags & FTRACE_FL_DISABLED)
1912 continue;
1913
1914 if (rec == end)
1915 goto err_out;
1916
1917 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1918 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1919 if (in_old == in_new)
1920 continue;
1921
1922 if (in_new)
1923 rec->flags &= ~FTRACE_FL_IPMODIFY;
1924 else
1925 rec->flags |= FTRACE_FL_IPMODIFY;
1926 } while_for_each_ftrace_rec();
1927
1928err_out:
1929 return -EBUSY;
1930}
1931
1932static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1933{
1934 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1935
1936 if (ftrace_hash_empty(hash))
1937 hash = NULL;
1938
1939 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1940}
1941
1942/* Disabling always succeeds */
1943static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1944{
1945 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1946
1947 if (ftrace_hash_empty(hash))
1948 hash = NULL;
1949
1950 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1951}
1952
1953static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1954 struct ftrace_hash *new_hash)
1955{
1956 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1957
1958 if (ftrace_hash_empty(old_hash))
1959 old_hash = NULL;
1960
1961 if (ftrace_hash_empty(new_hash))
1962 new_hash = NULL;
1963
1964 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1965}
1966
1967static void print_ip_ins(const char *fmt, const unsigned char *p)
1968{
1969 int i;
1970
1971 printk(KERN_CONT "%s", fmt);
1972
1973 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1974 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1975}
1976
1977enum ftrace_bug_type ftrace_bug_type;
1978const void *ftrace_expected;
1979
1980static void print_bug_type(void)
1981{
1982 switch (ftrace_bug_type) {
1983 case FTRACE_BUG_UNKNOWN:
1984 break;
1985 case FTRACE_BUG_INIT:
1986 pr_info("Initializing ftrace call sites\n");
1987 break;
1988 case FTRACE_BUG_NOP:
1989 pr_info("Setting ftrace call site to NOP\n");
1990 break;
1991 case FTRACE_BUG_CALL:
1992 pr_info("Setting ftrace call site to call ftrace function\n");
1993 break;
1994 case FTRACE_BUG_UPDATE:
1995 pr_info("Updating ftrace call site to call a different ftrace function\n");
1996 break;
1997 }
1998}
1999
2000/**
2001 * ftrace_bug - report and shutdown function tracer
2002 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2003 * @rec: The record that failed
2004 *
2005 * The arch code that enables or disables the function tracing
2006 * can call ftrace_bug() when it has detected a problem in
2007 * modifying the code. @failed should be one of either:
2008 * EFAULT - if the problem happens on reading the @ip address
2009 * EINVAL - if what is read at @ip is not what was expected
2010 * EPERM - if the problem happens on writing to the @ip address
2011 */
2012void ftrace_bug(int failed, struct dyn_ftrace *rec)
2013{
2014 unsigned long ip = rec ? rec->ip : 0;
2015
2016 pr_info("------------[ ftrace bug ]------------\n");
2017
2018 switch (failed) {
2019 case -EFAULT:
2020 pr_info("ftrace faulted on modifying ");
2021 print_ip_sym(KERN_INFO, ip);
2022 break;
2023 case -EINVAL:
2024 pr_info("ftrace failed to modify ");
2025 print_ip_sym(KERN_INFO, ip);
2026 print_ip_ins(" actual: ", (unsigned char *)ip);
2027 pr_cont("\n");
2028 if (ftrace_expected) {
2029 print_ip_ins(" expected: ", ftrace_expected);
2030 pr_cont("\n");
2031 }
2032 break;
2033 case -EPERM:
2034 pr_info("ftrace faulted on writing ");
2035 print_ip_sym(KERN_INFO, ip);
2036 break;
2037 default:
2038 pr_info("ftrace faulted on unknown error ");
2039 print_ip_sym(KERN_INFO, ip);
2040 }
2041 print_bug_type();
2042 if (rec) {
2043 struct ftrace_ops *ops = NULL;
2044
2045 pr_info("ftrace record flags: %lx\n", rec->flags);
2046 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2047 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2048 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2049 ops = ftrace_find_tramp_ops_any(rec);
2050 if (ops) {
2051 do {
2052 pr_cont("\ttramp: %pS (%pS)",
2053 (void *)ops->trampoline,
2054 (void *)ops->func);
2055 ops = ftrace_find_tramp_ops_next(rec, ops);
2056 } while (ops);
2057 } else
2058 pr_cont("\ttramp: ERROR!");
2059
2060 }
2061 ip = ftrace_get_addr_curr(rec);
2062 pr_cont("\n expected tramp: %lx\n", ip);
2063 }
2064
2065 FTRACE_WARN_ON_ONCE(1);
2066}
2067
2068static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2069{
2070 unsigned long flag = 0UL;
2071
2072 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2073
2074 if (rec->flags & FTRACE_FL_DISABLED)
2075 return FTRACE_UPDATE_IGNORE;
2076
2077 /*
2078 * If we are updating calls:
2079 *
2080 * If the record has a ref count, then we need to enable it
2081 * because someone is using it.
2082 *
2083 * Otherwise we make sure its disabled.
2084 *
2085 * If we are disabling calls, then disable all records that
2086 * are enabled.
2087 */
2088 if (enable && ftrace_rec_count(rec))
2089 flag = FTRACE_FL_ENABLED;
2090
2091 /*
2092 * If enabling and the REGS flag does not match the REGS_EN, or
2093 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2094 * this record. Set flags to fail the compare against ENABLED.
2095 * Same for direct calls.
2096 */
2097 if (flag) {
2098 if (!(rec->flags & FTRACE_FL_REGS) !=
2099 !(rec->flags & FTRACE_FL_REGS_EN))
2100 flag |= FTRACE_FL_REGS;
2101
2102 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2103 !(rec->flags & FTRACE_FL_TRAMP_EN))
2104 flag |= FTRACE_FL_TRAMP;
2105
2106 /*
2107 * Direct calls are special, as count matters.
2108 * We must test the record for direct, if the
2109 * DIRECT and DIRECT_EN do not match, but only
2110 * if the count is 1. That's because, if the
2111 * count is something other than one, we do not
2112 * want the direct enabled (it will be done via the
2113 * direct helper). But if DIRECT_EN is set, and
2114 * the count is not one, we need to clear it.
2115 */
2116 if (ftrace_rec_count(rec) == 1) {
2117 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2118 !(rec->flags & FTRACE_FL_DIRECT_EN))
2119 flag |= FTRACE_FL_DIRECT;
2120 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2121 flag |= FTRACE_FL_DIRECT;
2122 }
2123 }
2124
2125 /* If the state of this record hasn't changed, then do nothing */
2126 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2127 return FTRACE_UPDATE_IGNORE;
2128
2129 if (flag) {
2130 /* Save off if rec is being enabled (for return value) */
2131 flag ^= rec->flags & FTRACE_FL_ENABLED;
2132
2133 if (update) {
2134 rec->flags |= FTRACE_FL_ENABLED;
2135 if (flag & FTRACE_FL_REGS) {
2136 if (rec->flags & FTRACE_FL_REGS)
2137 rec->flags |= FTRACE_FL_REGS_EN;
2138 else
2139 rec->flags &= ~FTRACE_FL_REGS_EN;
2140 }
2141 if (flag & FTRACE_FL_TRAMP) {
2142 if (rec->flags & FTRACE_FL_TRAMP)
2143 rec->flags |= FTRACE_FL_TRAMP_EN;
2144 else
2145 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2146 }
2147 if (flag & FTRACE_FL_DIRECT) {
2148 /*
2149 * If there's only one user (direct_ops helper)
2150 * then we can call the direct function
2151 * directly (no ftrace trampoline).
2152 */
2153 if (ftrace_rec_count(rec) == 1) {
2154 if (rec->flags & FTRACE_FL_DIRECT)
2155 rec->flags |= FTRACE_FL_DIRECT_EN;
2156 else
2157 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2158 } else {
2159 /*
2160 * Can only call directly if there's
2161 * only one callback to the function.
2162 */
2163 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2164 }
2165 }
2166 }
2167
2168 /*
2169 * If this record is being updated from a nop, then
2170 * return UPDATE_MAKE_CALL.
2171 * Otherwise,
2172 * return UPDATE_MODIFY_CALL to tell the caller to convert
2173 * from the save regs, to a non-save regs function or
2174 * vice versa, or from a trampoline call.
2175 */
2176 if (flag & FTRACE_FL_ENABLED) {
2177 ftrace_bug_type = FTRACE_BUG_CALL;
2178 return FTRACE_UPDATE_MAKE_CALL;
2179 }
2180
2181 ftrace_bug_type = FTRACE_BUG_UPDATE;
2182 return FTRACE_UPDATE_MODIFY_CALL;
2183 }
2184
2185 if (update) {
2186 /* If there's no more users, clear all flags */
2187 if (!ftrace_rec_count(rec))
2188 rec->flags = 0;
2189 else
2190 /*
2191 * Just disable the record, but keep the ops TRAMP
2192 * and REGS states. The _EN flags must be disabled though.
2193 */
2194 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2195 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2196 }
2197
2198 ftrace_bug_type = FTRACE_BUG_NOP;
2199 return FTRACE_UPDATE_MAKE_NOP;
2200}
2201
2202/**
2203 * ftrace_update_record, set a record that now is tracing or not
2204 * @rec: the record to update
2205 * @enable: set to true if the record is tracing, false to force disable
2206 *
2207 * The records that represent all functions that can be traced need
2208 * to be updated when tracing has been enabled.
2209 */
2210int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2211{
2212 return ftrace_check_record(rec, enable, true);
2213}
2214
2215/**
2216 * ftrace_test_record, check if the record has been enabled or not
2217 * @rec: the record to test
2218 * @enable: set to true to check if enabled, false if it is disabled
2219 *
2220 * The arch code may need to test if a record is already set to
2221 * tracing to determine how to modify the function code that it
2222 * represents.
2223 */
2224int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2225{
2226 return ftrace_check_record(rec, enable, false);
2227}
2228
2229static struct ftrace_ops *
2230ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2231{
2232 struct ftrace_ops *op;
2233 unsigned long ip = rec->ip;
2234
2235 do_for_each_ftrace_op(op, ftrace_ops_list) {
2236
2237 if (!op->trampoline)
2238 continue;
2239
2240 if (hash_contains_ip(ip, op->func_hash))
2241 return op;
2242 } while_for_each_ftrace_op(op);
2243
2244 return NULL;
2245}
2246
2247static struct ftrace_ops *
2248ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2249 struct ftrace_ops *op)
2250{
2251 unsigned long ip = rec->ip;
2252
2253 while_for_each_ftrace_op(op) {
2254
2255 if (!op->trampoline)
2256 continue;
2257
2258 if (hash_contains_ip(ip, op->func_hash))
2259 return op;
2260 }
2261
2262 return NULL;
2263}
2264
2265static struct ftrace_ops *
2266ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2267{
2268 struct ftrace_ops *op;
2269 unsigned long ip = rec->ip;
2270
2271 /*
2272 * Need to check removed ops first.
2273 * If they are being removed, and this rec has a tramp,
2274 * and this rec is in the ops list, then it would be the
2275 * one with the tramp.
2276 */
2277 if (removed_ops) {
2278 if (hash_contains_ip(ip, &removed_ops->old_hash))
2279 return removed_ops;
2280 }
2281
2282 /*
2283 * Need to find the current trampoline for a rec.
2284 * Now, a trampoline is only attached to a rec if there
2285 * was a single 'ops' attached to it. But this can be called
2286 * when we are adding another op to the rec or removing the
2287 * current one. Thus, if the op is being added, we can
2288 * ignore it because it hasn't attached itself to the rec
2289 * yet.
2290 *
2291 * If an ops is being modified (hooking to different functions)
2292 * then we don't care about the new functions that are being
2293 * added, just the old ones (that are probably being removed).
2294 *
2295 * If we are adding an ops to a function that already is using
2296 * a trampoline, it needs to be removed (trampolines are only
2297 * for single ops connected), then an ops that is not being
2298 * modified also needs to be checked.
2299 */
2300 do_for_each_ftrace_op(op, ftrace_ops_list) {
2301
2302 if (!op->trampoline)
2303 continue;
2304
2305 /*
2306 * If the ops is being added, it hasn't gotten to
2307 * the point to be removed from this tree yet.
2308 */
2309 if (op->flags & FTRACE_OPS_FL_ADDING)
2310 continue;
2311
2312
2313 /*
2314 * If the ops is being modified and is in the old
2315 * hash, then it is probably being removed from this
2316 * function.
2317 */
2318 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2319 hash_contains_ip(ip, &op->old_hash))
2320 return op;
2321 /*
2322 * If the ops is not being added or modified, and it's
2323 * in its normal filter hash, then this must be the one
2324 * we want!
2325 */
2326 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2327 hash_contains_ip(ip, op->func_hash))
2328 return op;
2329
2330 } while_for_each_ftrace_op(op);
2331
2332 return NULL;
2333}
2334
2335static struct ftrace_ops *
2336ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2337{
2338 struct ftrace_ops *op;
2339 unsigned long ip = rec->ip;
2340
2341 do_for_each_ftrace_op(op, ftrace_ops_list) {
2342 /* pass rec in as regs to have non-NULL val */
2343 if (hash_contains_ip(ip, op->func_hash))
2344 return op;
2345 } while_for_each_ftrace_op(op);
2346
2347 return NULL;
2348}
2349
2350#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2351/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2352static struct ftrace_hash *direct_functions = EMPTY_HASH;
2353static DEFINE_MUTEX(direct_mutex);
2354int ftrace_direct_func_count;
2355
2356/*
2357 * Search the direct_functions hash to see if the given instruction pointer
2358 * has a direct caller attached to it.
2359 */
2360unsigned long ftrace_find_rec_direct(unsigned long ip)
2361{
2362 struct ftrace_func_entry *entry;
2363
2364 entry = __ftrace_lookup_ip(direct_functions, ip);
2365 if (!entry)
2366 return 0;
2367
2368 return entry->direct;
2369}
2370
2371static void call_direct_funcs(unsigned long ip, unsigned long pip,
2372 struct ftrace_ops *ops, struct pt_regs *regs)
2373{
2374 unsigned long addr;
2375
2376 addr = ftrace_find_rec_direct(ip);
2377 if (!addr)
2378 return;
2379
2380 arch_ftrace_set_direct_caller(regs, addr);
2381}
2382
2383struct ftrace_ops direct_ops = {
2384 .func = call_direct_funcs,
2385 .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
2386 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2387 | FTRACE_OPS_FL_PERMANENT,
2388 /*
2389 * By declaring the main trampoline as this trampoline
2390 * it will never have one allocated for it. Allocated
2391 * trampolines should not call direct functions.
2392 * The direct_ops should only be called by the builtin
2393 * ftrace_regs_caller trampoline.
2394 */
2395 .trampoline = FTRACE_REGS_ADDR,
2396};
2397#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2398
2399/**
2400 * ftrace_get_addr_new - Get the call address to set to
2401 * @rec: The ftrace record descriptor
2402 *
2403 * If the record has the FTRACE_FL_REGS set, that means that it
2404 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2405 * is not not set, then it wants to convert to the normal callback.
2406 *
2407 * Returns the address of the trampoline to set to
2408 */
2409unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2410{
2411 struct ftrace_ops *ops;
2412 unsigned long addr;
2413
2414 if ((rec->flags & FTRACE_FL_DIRECT) &&
2415 (ftrace_rec_count(rec) == 1)) {
2416 addr = ftrace_find_rec_direct(rec->ip);
2417 if (addr)
2418 return addr;
2419 WARN_ON_ONCE(1);
2420 }
2421
2422 /* Trampolines take precedence over regs */
2423 if (rec->flags & FTRACE_FL_TRAMP) {
2424 ops = ftrace_find_tramp_ops_new(rec);
2425 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2426 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2427 (void *)rec->ip, (void *)rec->ip, rec->flags);
2428 /* Ftrace is shutting down, return anything */
2429 return (unsigned long)FTRACE_ADDR;
2430 }
2431 return ops->trampoline;
2432 }
2433
2434 if (rec->flags & FTRACE_FL_REGS)
2435 return (unsigned long)FTRACE_REGS_ADDR;
2436 else
2437 return (unsigned long)FTRACE_ADDR;
2438}
2439
2440/**
2441 * ftrace_get_addr_curr - Get the call address that is already there
2442 * @rec: The ftrace record descriptor
2443 *
2444 * The FTRACE_FL_REGS_EN is set when the record already points to
2445 * a function that saves all the regs. Basically the '_EN' version
2446 * represents the current state of the function.
2447 *
2448 * Returns the address of the trampoline that is currently being called
2449 */
2450unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2451{
2452 struct ftrace_ops *ops;
2453 unsigned long addr;
2454
2455 /* Direct calls take precedence over trampolines */
2456 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2457 addr = ftrace_find_rec_direct(rec->ip);
2458 if (addr)
2459 return addr;
2460 WARN_ON_ONCE(1);
2461 }
2462
2463 /* Trampolines take precedence over regs */
2464 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2465 ops = ftrace_find_tramp_ops_curr(rec);
2466 if (FTRACE_WARN_ON(!ops)) {
2467 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2468 (void *)rec->ip, (void *)rec->ip);
2469 /* Ftrace is shutting down, return anything */
2470 return (unsigned long)FTRACE_ADDR;
2471 }
2472 return ops->trampoline;
2473 }
2474
2475 if (rec->flags & FTRACE_FL_REGS_EN)
2476 return (unsigned long)FTRACE_REGS_ADDR;
2477 else
2478 return (unsigned long)FTRACE_ADDR;
2479}
2480
2481static int
2482__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2483{
2484 unsigned long ftrace_old_addr;
2485 unsigned long ftrace_addr;
2486 int ret;
2487
2488 ftrace_addr = ftrace_get_addr_new(rec);
2489
2490 /* This needs to be done before we call ftrace_update_record */
2491 ftrace_old_addr = ftrace_get_addr_curr(rec);
2492
2493 ret = ftrace_update_record(rec, enable);
2494
2495 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2496
2497 switch (ret) {
2498 case FTRACE_UPDATE_IGNORE:
2499 return 0;
2500
2501 case FTRACE_UPDATE_MAKE_CALL:
2502 ftrace_bug_type = FTRACE_BUG_CALL;
2503 return ftrace_make_call(rec, ftrace_addr);
2504
2505 case FTRACE_UPDATE_MAKE_NOP:
2506 ftrace_bug_type = FTRACE_BUG_NOP;
2507 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2508
2509 case FTRACE_UPDATE_MODIFY_CALL:
2510 ftrace_bug_type = FTRACE_BUG_UPDATE;
2511 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2512 }
2513
2514 return -1; /* unknown ftrace bug */
2515}
2516
2517void __weak ftrace_replace_code(int mod_flags)
2518{
2519 struct dyn_ftrace *rec;
2520 struct ftrace_page *pg;
2521 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2522 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2523 int failed;
2524
2525 if (unlikely(ftrace_disabled))
2526 return;
2527
2528 do_for_each_ftrace_rec(pg, rec) {
2529
2530 if (rec->flags & FTRACE_FL_DISABLED)
2531 continue;
2532
2533 failed = __ftrace_replace_code(rec, enable);
2534 if (failed) {
2535 ftrace_bug(failed, rec);
2536 /* Stop processing */
2537 return;
2538 }
2539 if (schedulable)
2540 cond_resched();
2541 } while_for_each_ftrace_rec();
2542}
2543
2544struct ftrace_rec_iter {
2545 struct ftrace_page *pg;
2546 int index;
2547};
2548
2549/**
2550 * ftrace_rec_iter_start, start up iterating over traced functions
2551 *
2552 * Returns an iterator handle that is used to iterate over all
2553 * the records that represent address locations where functions
2554 * are traced.
2555 *
2556 * May return NULL if no records are available.
2557 */
2558struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2559{
2560 /*
2561 * We only use a single iterator.
2562 * Protected by the ftrace_lock mutex.
2563 */
2564 static struct ftrace_rec_iter ftrace_rec_iter;
2565 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2566
2567 iter->pg = ftrace_pages_start;
2568 iter->index = 0;
2569
2570 /* Could have empty pages */
2571 while (iter->pg && !iter->pg->index)
2572 iter->pg = iter->pg->next;
2573
2574 if (!iter->pg)
2575 return NULL;
2576
2577 return iter;
2578}
2579
2580/**
2581 * ftrace_rec_iter_next, get the next record to process.
2582 * @iter: The handle to the iterator.
2583 *
2584 * Returns the next iterator after the given iterator @iter.
2585 */
2586struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2587{
2588 iter->index++;
2589
2590 if (iter->index >= iter->pg->index) {
2591 iter->pg = iter->pg->next;
2592 iter->index = 0;
2593
2594 /* Could have empty pages */
2595 while (iter->pg && !iter->pg->index)
2596 iter->pg = iter->pg->next;
2597 }
2598
2599 if (!iter->pg)
2600 return NULL;
2601
2602 return iter;
2603}
2604
2605/**
2606 * ftrace_rec_iter_record, get the record at the iterator location
2607 * @iter: The current iterator location
2608 *
2609 * Returns the record that the current @iter is at.
2610 */
2611struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2612{
2613 return &iter->pg->records[iter->index];
2614}
2615
2616static int
2617ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2618{
2619 int ret;
2620
2621 if (unlikely(ftrace_disabled))
2622 return 0;
2623
2624 ret = ftrace_init_nop(mod, rec);
2625 if (ret) {
2626 ftrace_bug_type = FTRACE_BUG_INIT;
2627 ftrace_bug(ret, rec);
2628 return 0;
2629 }
2630 return 1;
2631}
2632
2633/*
2634 * archs can override this function if they must do something
2635 * before the modifying code is performed.
2636 */
2637int __weak ftrace_arch_code_modify_prepare(void)
2638{
2639 return 0;
2640}
2641
2642/*
2643 * archs can override this function if they must do something
2644 * after the modifying code is performed.
2645 */
2646int __weak ftrace_arch_code_modify_post_process(void)
2647{
2648 return 0;
2649}
2650
2651void ftrace_modify_all_code(int command)
2652{
2653 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2654 int mod_flags = 0;
2655 int err = 0;
2656
2657 if (command & FTRACE_MAY_SLEEP)
2658 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2659
2660 /*
2661 * If the ftrace_caller calls a ftrace_ops func directly,
2662 * we need to make sure that it only traces functions it
2663 * expects to trace. When doing the switch of functions,
2664 * we need to update to the ftrace_ops_list_func first
2665 * before the transition between old and new calls are set,
2666 * as the ftrace_ops_list_func will check the ops hashes
2667 * to make sure the ops are having the right functions
2668 * traced.
2669 */
2670 if (update) {
2671 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2672 if (FTRACE_WARN_ON(err))
2673 return;
2674 }
2675
2676 if (command & FTRACE_UPDATE_CALLS)
2677 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2678 else if (command & FTRACE_DISABLE_CALLS)
2679 ftrace_replace_code(mod_flags);
2680
2681 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2682 function_trace_op = set_function_trace_op;
2683 smp_wmb();
2684 /* If irqs are disabled, we are in stop machine */
2685 if (!irqs_disabled())
2686 smp_call_function(ftrace_sync_ipi, NULL, 1);
2687 err = ftrace_update_ftrace_func(ftrace_trace_function);
2688 if (FTRACE_WARN_ON(err))
2689 return;
2690 }
2691
2692 if (command & FTRACE_START_FUNC_RET)
2693 err = ftrace_enable_ftrace_graph_caller();
2694 else if (command & FTRACE_STOP_FUNC_RET)
2695 err = ftrace_disable_ftrace_graph_caller();
2696 FTRACE_WARN_ON(err);
2697}
2698
2699static int __ftrace_modify_code(void *data)
2700{
2701 int *command = data;
2702
2703 ftrace_modify_all_code(*command);
2704
2705 return 0;
2706}
2707
2708/**
2709 * ftrace_run_stop_machine, go back to the stop machine method
2710 * @command: The command to tell ftrace what to do
2711 *
2712 * If an arch needs to fall back to the stop machine method, the
2713 * it can call this function.
2714 */
2715void ftrace_run_stop_machine(int command)
2716{
2717 stop_machine(__ftrace_modify_code, &command, NULL);
2718}
2719
2720/**
2721 * arch_ftrace_update_code, modify the code to trace or not trace
2722 * @command: The command that needs to be done
2723 *
2724 * Archs can override this function if it does not need to
2725 * run stop_machine() to modify code.
2726 */
2727void __weak arch_ftrace_update_code(int command)
2728{
2729 ftrace_run_stop_machine(command);
2730}
2731
2732static void ftrace_run_update_code(int command)
2733{
2734 int ret;
2735
2736 ret = ftrace_arch_code_modify_prepare();
2737 FTRACE_WARN_ON(ret);
2738 if (ret)
2739 return;
2740
2741 /*
2742 * By default we use stop_machine() to modify the code.
2743 * But archs can do what ever they want as long as it
2744 * is safe. The stop_machine() is the safest, but also
2745 * produces the most overhead.
2746 */
2747 arch_ftrace_update_code(command);
2748
2749 ret = ftrace_arch_code_modify_post_process();
2750 FTRACE_WARN_ON(ret);
2751}
2752
2753static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2754 struct ftrace_ops_hash *old_hash)
2755{
2756 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2757 ops->old_hash.filter_hash = old_hash->filter_hash;
2758 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2759 ftrace_run_update_code(command);
2760 ops->old_hash.filter_hash = NULL;
2761 ops->old_hash.notrace_hash = NULL;
2762 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2763}
2764
2765static ftrace_func_t saved_ftrace_func;
2766static int ftrace_start_up;
2767
2768void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2769{
2770}
2771
2772/* List of trace_ops that have allocated trampolines */
2773static LIST_HEAD(ftrace_ops_trampoline_list);
2774
2775static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2776{
2777 lockdep_assert_held(&ftrace_lock);
2778 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2779}
2780
2781static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2782{
2783 lockdep_assert_held(&ftrace_lock);
2784 list_del_rcu(&ops->list);
2785 synchronize_rcu();
2786}
2787
2788/*
2789 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2790 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2791 * not a module.
2792 */
2793#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2794#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2795
2796static void ftrace_trampoline_free(struct ftrace_ops *ops)
2797{
2798 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2799 ops->trampoline) {
2800 /*
2801 * Record the text poke event before the ksymbol unregister
2802 * event.
2803 */
2804 perf_event_text_poke((void *)ops->trampoline,
2805 (void *)ops->trampoline,
2806 ops->trampoline_size, NULL, 0);
2807 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2808 ops->trampoline, ops->trampoline_size,
2809 true, FTRACE_TRAMPOLINE_SYM);
2810 /* Remove from kallsyms after the perf events */
2811 ftrace_remove_trampoline_from_kallsyms(ops);
2812 }
2813
2814 arch_ftrace_trampoline_free(ops);
2815}
2816
2817static void ftrace_startup_enable(int command)
2818{
2819 if (saved_ftrace_func != ftrace_trace_function) {
2820 saved_ftrace_func = ftrace_trace_function;
2821 command |= FTRACE_UPDATE_TRACE_FUNC;
2822 }
2823
2824 if (!command || !ftrace_enabled)
2825 return;
2826
2827 ftrace_run_update_code(command);
2828}
2829
2830static void ftrace_startup_all(int command)
2831{
2832 update_all_ops = true;
2833 ftrace_startup_enable(command);
2834 update_all_ops = false;
2835}
2836
2837int ftrace_startup(struct ftrace_ops *ops, int command)
2838{
2839 int ret;
2840
2841 if (unlikely(ftrace_disabled))
2842 return -ENODEV;
2843
2844 ret = __register_ftrace_function(ops);
2845 if (ret)
2846 return ret;
2847
2848 ftrace_start_up++;
2849
2850 /*
2851 * Note that ftrace probes uses this to start up
2852 * and modify functions it will probe. But we still
2853 * set the ADDING flag for modification, as probes
2854 * do not have trampolines. If they add them in the
2855 * future, then the probes will need to distinguish
2856 * between adding and updating probes.
2857 */
2858 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2859
2860 ret = ftrace_hash_ipmodify_enable(ops);
2861 if (ret < 0) {
2862 /* Rollback registration process */
2863 __unregister_ftrace_function(ops);
2864 ftrace_start_up--;
2865 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2866 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2867 ftrace_trampoline_free(ops);
2868 return ret;
2869 }
2870
2871 if (ftrace_hash_rec_enable(ops, 1))
2872 command |= FTRACE_UPDATE_CALLS;
2873
2874 ftrace_startup_enable(command);
2875
2876 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2877
2878 return 0;
2879}
2880
2881int ftrace_shutdown(struct ftrace_ops *ops, int command)
2882{
2883 int ret;
2884
2885 if (unlikely(ftrace_disabled))
2886 return -ENODEV;
2887
2888 ret = __unregister_ftrace_function(ops);
2889 if (ret)
2890 return ret;
2891
2892 ftrace_start_up--;
2893 /*
2894 * Just warn in case of unbalance, no need to kill ftrace, it's not
2895 * critical but the ftrace_call callers may be never nopped again after
2896 * further ftrace uses.
2897 */
2898 WARN_ON_ONCE(ftrace_start_up < 0);
2899
2900 /* Disabling ipmodify never fails */
2901 ftrace_hash_ipmodify_disable(ops);
2902
2903 if (ftrace_hash_rec_disable(ops, 1))
2904 command |= FTRACE_UPDATE_CALLS;
2905
2906 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2907
2908 if (saved_ftrace_func != ftrace_trace_function) {
2909 saved_ftrace_func = ftrace_trace_function;
2910 command |= FTRACE_UPDATE_TRACE_FUNC;
2911 }
2912
2913 if (!command || !ftrace_enabled) {
2914 /*
2915 * If these are dynamic or per_cpu ops, they still
2916 * need their data freed. Since, function tracing is
2917 * not currently active, we can just free them
2918 * without synchronizing all CPUs.
2919 */
2920 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2921 goto free_ops;
2922
2923 return 0;
2924 }
2925
2926 /*
2927 * If the ops uses a trampoline, then it needs to be
2928 * tested first on update.
2929 */
2930 ops->flags |= FTRACE_OPS_FL_REMOVING;
2931 removed_ops = ops;
2932
2933 /* The trampoline logic checks the old hashes */
2934 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2935 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2936
2937 ftrace_run_update_code(command);
2938
2939 /*
2940 * If there's no more ops registered with ftrace, run a
2941 * sanity check to make sure all rec flags are cleared.
2942 */
2943 if (rcu_dereference_protected(ftrace_ops_list,
2944 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2945 struct ftrace_page *pg;
2946 struct dyn_ftrace *rec;
2947
2948 do_for_each_ftrace_rec(pg, rec) {
2949 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2950 pr_warn(" %pS flags:%lx\n",
2951 (void *)rec->ip, rec->flags);
2952 } while_for_each_ftrace_rec();
2953 }
2954
2955 ops->old_hash.filter_hash = NULL;
2956 ops->old_hash.notrace_hash = NULL;
2957
2958 removed_ops = NULL;
2959 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2960
2961 /*
2962 * Dynamic ops may be freed, we must make sure that all
2963 * callers are done before leaving this function.
2964 * The same goes for freeing the per_cpu data of the per_cpu
2965 * ops.
2966 */
2967 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2968 /*
2969 * We need to do a hard force of sched synchronization.
2970 * This is because we use preempt_disable() to do RCU, but
2971 * the function tracers can be called where RCU is not watching
2972 * (like before user_exit()). We can not rely on the RCU
2973 * infrastructure to do the synchronization, thus we must do it
2974 * ourselves.
2975 */
2976 synchronize_rcu_tasks_rude();
2977
2978 /*
2979 * When the kernel is preeptive, tasks can be preempted
2980 * while on a ftrace trampoline. Just scheduling a task on
2981 * a CPU is not good enough to flush them. Calling
2982 * synchornize_rcu_tasks() will wait for those tasks to
2983 * execute and either schedule voluntarily or enter user space.
2984 */
2985 if (IS_ENABLED(CONFIG_PREEMPTION))
2986 synchronize_rcu_tasks();
2987
2988 free_ops:
2989 ftrace_trampoline_free(ops);
2990 }
2991
2992 return 0;
2993}
2994
2995static void ftrace_startup_sysctl(void)
2996{
2997 int command;
2998
2999 if (unlikely(ftrace_disabled))
3000 return;
3001
3002 /* Force update next time */
3003 saved_ftrace_func = NULL;
3004 /* ftrace_start_up is true if we want ftrace running */
3005 if (ftrace_start_up) {
3006 command = FTRACE_UPDATE_CALLS;
3007 if (ftrace_graph_active)
3008 command |= FTRACE_START_FUNC_RET;
3009 ftrace_startup_enable(command);
3010 }
3011}
3012
3013static void ftrace_shutdown_sysctl(void)
3014{
3015 int command;
3016
3017 if (unlikely(ftrace_disabled))
3018 return;
3019
3020 /* ftrace_start_up is true if ftrace is running */
3021 if (ftrace_start_up) {
3022 command = FTRACE_DISABLE_CALLS;
3023 if (ftrace_graph_active)
3024 command |= FTRACE_STOP_FUNC_RET;
3025 ftrace_run_update_code(command);
3026 }
3027}
3028
3029static u64 ftrace_update_time;
3030unsigned long ftrace_update_tot_cnt;
3031unsigned long ftrace_number_of_pages;
3032unsigned long ftrace_number_of_groups;
3033
3034static inline int ops_traces_mod(struct ftrace_ops *ops)
3035{
3036 /*
3037 * Filter_hash being empty will default to trace module.
3038 * But notrace hash requires a test of individual module functions.
3039 */
3040 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3041 ftrace_hash_empty(ops->func_hash->notrace_hash);
3042}
3043
3044/*
3045 * Check if the current ops references the record.
3046 *
3047 * If the ops traces all functions, then it was already accounted for.
3048 * If the ops does not trace the current record function, skip it.
3049 * If the ops ignores the function via notrace filter, skip it.
3050 */
3051static inline bool
3052ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3053{
3054 /* If ops isn't enabled, ignore it */
3055 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3056 return false;
3057
3058 /* If ops traces all then it includes this function */
3059 if (ops_traces_mod(ops))
3060 return true;
3061
3062 /* The function must be in the filter */
3063 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3064 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3065 return false;
3066
3067 /* If in notrace hash, we ignore it too */
3068 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3069 return false;
3070
3071 return true;
3072}
3073
3074static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3075{
3076 struct ftrace_page *pg;
3077 struct dyn_ftrace *p;
3078 u64 start, stop;
3079 unsigned long update_cnt = 0;
3080 unsigned long rec_flags = 0;
3081 int i;
3082
3083 start = ftrace_now(raw_smp_processor_id());
3084
3085 /*
3086 * When a module is loaded, this function is called to convert
3087 * the calls to mcount in its text to nops, and also to create
3088 * an entry in the ftrace data. Now, if ftrace is activated
3089 * after this call, but before the module sets its text to
3090 * read-only, the modification of enabling ftrace can fail if
3091 * the read-only is done while ftrace is converting the calls.
3092 * To prevent this, the module's records are set as disabled
3093 * and will be enabled after the call to set the module's text
3094 * to read-only.
3095 */
3096 if (mod)
3097 rec_flags |= FTRACE_FL_DISABLED;
3098
3099 for (pg = new_pgs; pg; pg = pg->next) {
3100
3101 for (i = 0; i < pg->index; i++) {
3102
3103 /* If something went wrong, bail without enabling anything */
3104 if (unlikely(ftrace_disabled))
3105 return -1;
3106
3107 p = &pg->records[i];
3108 p->flags = rec_flags;
3109
3110 /*
3111 * Do the initial record conversion from mcount jump
3112 * to the NOP instructions.
3113 */
3114 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3115 !ftrace_nop_initialize(mod, p))
3116 break;
3117
3118 update_cnt++;
3119 }
3120 }
3121
3122 stop = ftrace_now(raw_smp_processor_id());
3123 ftrace_update_time = stop - start;
3124 ftrace_update_tot_cnt += update_cnt;
3125
3126 return 0;
3127}
3128
3129static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3130{
3131 int order;
3132 int cnt;
3133
3134 if (WARN_ON(!count))
3135 return -EINVAL;
3136
3137 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3138
3139 /*
3140 * We want to fill as much as possible. No more than a page
3141 * may be empty.
3142 */
3143 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3144 order--;
3145
3146 again:
3147 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3148
3149 if (!pg->records) {
3150 /* if we can't allocate this size, try something smaller */
3151 if (!order)
3152 return -ENOMEM;
3153 order >>= 1;
3154 goto again;
3155 }
3156
3157 ftrace_number_of_pages += 1 << order;
3158 ftrace_number_of_groups++;
3159
3160 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3161 pg->size = cnt;
3162
3163 if (cnt > count)
3164 cnt = count;
3165
3166 return cnt;
3167}
3168
3169static struct ftrace_page *
3170ftrace_allocate_pages(unsigned long num_to_init)
3171{
3172 struct ftrace_page *start_pg;
3173 struct ftrace_page *pg;
3174 int order;
3175 int cnt;
3176
3177 if (!num_to_init)
3178 return NULL;
3179
3180 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3181 if (!pg)
3182 return NULL;
3183
3184 /*
3185 * Try to allocate as much as possible in one continues
3186 * location that fills in all of the space. We want to
3187 * waste as little space as possible.
3188 */
3189 for (;;) {
3190 cnt = ftrace_allocate_records(pg, num_to_init);
3191 if (cnt < 0)
3192 goto free_pages;
3193
3194 num_to_init -= cnt;
3195 if (!num_to_init)
3196 break;
3197
3198 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3199 if (!pg->next)
3200 goto free_pages;
3201
3202 pg = pg->next;
3203 }
3204
3205 return start_pg;
3206
3207 free_pages:
3208 pg = start_pg;
3209 while (pg) {
3210 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3211 free_pages((unsigned long)pg->records, order);
3212 start_pg = pg->next;
3213 kfree(pg);
3214 pg = start_pg;
3215 ftrace_number_of_pages -= 1 << order;
3216 ftrace_number_of_groups--;
3217 }
3218 pr_info("ftrace: FAILED to allocate memory for functions\n");
3219 return NULL;
3220}
3221
3222#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3223
3224struct ftrace_iterator {
3225 loff_t pos;
3226 loff_t func_pos;
3227 loff_t mod_pos;
3228 struct ftrace_page *pg;
3229 struct dyn_ftrace *func;
3230 struct ftrace_func_probe *probe;
3231 struct ftrace_func_entry *probe_entry;
3232 struct trace_parser parser;
3233 struct ftrace_hash *hash;
3234 struct ftrace_ops *ops;
3235 struct trace_array *tr;
3236 struct list_head *mod_list;
3237 int pidx;
3238 int idx;
3239 unsigned flags;
3240};
3241
3242static void *
3243t_probe_next(struct seq_file *m, loff_t *pos)
3244{
3245 struct ftrace_iterator *iter = m->private;
3246 struct trace_array *tr = iter->ops->private;
3247 struct list_head *func_probes;
3248 struct ftrace_hash *hash;
3249 struct list_head *next;
3250 struct hlist_node *hnd = NULL;
3251 struct hlist_head *hhd;
3252 int size;
3253
3254 (*pos)++;
3255 iter->pos = *pos;
3256
3257 if (!tr)
3258 return NULL;
3259
3260 func_probes = &tr->func_probes;
3261 if (list_empty(func_probes))
3262 return NULL;
3263
3264 if (!iter->probe) {
3265 next = func_probes->next;
3266 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3267 }
3268
3269 if (iter->probe_entry)
3270 hnd = &iter->probe_entry->hlist;
3271
3272 hash = iter->probe->ops.func_hash->filter_hash;
3273
3274 /*
3275 * A probe being registered may temporarily have an empty hash
3276 * and it's at the end of the func_probes list.
3277 */
3278 if (!hash || hash == EMPTY_HASH)
3279 return NULL;
3280
3281 size = 1 << hash->size_bits;
3282
3283 retry:
3284 if (iter->pidx >= size) {
3285 if (iter->probe->list.next == func_probes)
3286 return NULL;
3287 next = iter->probe->list.next;
3288 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3289 hash = iter->probe->ops.func_hash->filter_hash;
3290 size = 1 << hash->size_bits;
3291 iter->pidx = 0;
3292 }
3293
3294 hhd = &hash->buckets[iter->pidx];
3295
3296 if (hlist_empty(hhd)) {
3297 iter->pidx++;
3298 hnd = NULL;
3299 goto retry;
3300 }
3301
3302 if (!hnd)
3303 hnd = hhd->first;
3304 else {
3305 hnd = hnd->next;
3306 if (!hnd) {
3307 iter->pidx++;
3308 goto retry;
3309 }
3310 }
3311
3312 if (WARN_ON_ONCE(!hnd))
3313 return NULL;
3314
3315 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3316
3317 return iter;
3318}
3319
3320static void *t_probe_start(struct seq_file *m, loff_t *pos)
3321{
3322 struct ftrace_iterator *iter = m->private;
3323 void *p = NULL;
3324 loff_t l;
3325
3326 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3327 return NULL;
3328
3329 if (iter->mod_pos > *pos)
3330 return NULL;
3331
3332 iter->probe = NULL;
3333 iter->probe_entry = NULL;
3334 iter->pidx = 0;
3335 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3336 p = t_probe_next(m, &l);
3337 if (!p)
3338 break;
3339 }
3340 if (!p)
3341 return NULL;
3342
3343 /* Only set this if we have an item */
3344 iter->flags |= FTRACE_ITER_PROBE;
3345
3346 return iter;
3347}
3348
3349static int
3350t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3351{
3352 struct ftrace_func_entry *probe_entry;
3353 struct ftrace_probe_ops *probe_ops;
3354 struct ftrace_func_probe *probe;
3355
3356 probe = iter->probe;
3357 probe_entry = iter->probe_entry;
3358
3359 if (WARN_ON_ONCE(!probe || !probe_entry))
3360 return -EIO;
3361
3362 probe_ops = probe->probe_ops;
3363
3364 if (probe_ops->print)
3365 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3366
3367 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3368 (void *)probe_ops->func);
3369
3370 return 0;
3371}
3372
3373static void *
3374t_mod_next(struct seq_file *m, loff_t *pos)
3375{
3376 struct ftrace_iterator *iter = m->private;
3377 struct trace_array *tr = iter->tr;
3378
3379 (*pos)++;
3380 iter->pos = *pos;
3381
3382 iter->mod_list = iter->mod_list->next;
3383
3384 if (iter->mod_list == &tr->mod_trace ||
3385 iter->mod_list == &tr->mod_notrace) {
3386 iter->flags &= ~FTRACE_ITER_MOD;
3387 return NULL;
3388 }
3389
3390 iter->mod_pos = *pos;
3391
3392 return iter;
3393}
3394
3395static void *t_mod_start(struct seq_file *m, loff_t *pos)
3396{
3397 struct ftrace_iterator *iter = m->private;
3398 void *p = NULL;
3399 loff_t l;
3400
3401 if (iter->func_pos > *pos)
3402 return NULL;
3403
3404 iter->mod_pos = iter->func_pos;
3405
3406 /* probes are only available if tr is set */
3407 if (!iter->tr)
3408 return NULL;
3409
3410 for (l = 0; l <= (*pos - iter->func_pos); ) {
3411 p = t_mod_next(m, &l);
3412 if (!p)
3413 break;
3414 }
3415 if (!p) {
3416 iter->flags &= ~FTRACE_ITER_MOD;
3417 return t_probe_start(m, pos);
3418 }
3419
3420 /* Only set this if we have an item */
3421 iter->flags |= FTRACE_ITER_MOD;
3422
3423 return iter;
3424}
3425
3426static int
3427t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3428{
3429 struct ftrace_mod_load *ftrace_mod;
3430 struct trace_array *tr = iter->tr;
3431
3432 if (WARN_ON_ONCE(!iter->mod_list) ||
3433 iter->mod_list == &tr->mod_trace ||
3434 iter->mod_list == &tr->mod_notrace)
3435 return -EIO;
3436
3437 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3438
3439 if (ftrace_mod->func)
3440 seq_printf(m, "%s", ftrace_mod->func);
3441 else
3442 seq_putc(m, '*');
3443
3444 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3445
3446 return 0;
3447}
3448
3449static void *
3450t_func_next(struct seq_file *m, loff_t *pos)
3451{
3452 struct ftrace_iterator *iter = m->private;
3453 struct dyn_ftrace *rec = NULL;
3454
3455 (*pos)++;
3456
3457 retry:
3458 if (iter->idx >= iter->pg->index) {
3459 if (iter->pg->next) {
3460 iter->pg = iter->pg->next;
3461 iter->idx = 0;
3462 goto retry;
3463 }
3464 } else {
3465 rec = &iter->pg->records[iter->idx++];
3466 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3467 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3468
3469 ((iter->flags & FTRACE_ITER_ENABLED) &&
3470 !(rec->flags & FTRACE_FL_ENABLED))) {
3471
3472 rec = NULL;
3473 goto retry;
3474 }
3475 }
3476
3477 if (!rec)
3478 return NULL;
3479
3480 iter->pos = iter->func_pos = *pos;
3481 iter->func = rec;
3482
3483 return iter;
3484}
3485
3486static void *
3487t_next(struct seq_file *m, void *v, loff_t *pos)
3488{
3489 struct ftrace_iterator *iter = m->private;
3490 loff_t l = *pos; /* t_probe_start() must use original pos */
3491 void *ret;
3492
3493 if (unlikely(ftrace_disabled))
3494 return NULL;
3495
3496 if (iter->flags & FTRACE_ITER_PROBE)
3497 return t_probe_next(m, pos);
3498
3499 if (iter->flags & FTRACE_ITER_MOD)
3500 return t_mod_next(m, pos);
3501
3502 if (iter->flags & FTRACE_ITER_PRINTALL) {
3503 /* next must increment pos, and t_probe_start does not */
3504 (*pos)++;
3505 return t_mod_start(m, &l);
3506 }
3507
3508 ret = t_func_next(m, pos);
3509
3510 if (!ret)
3511 return t_mod_start(m, &l);
3512
3513 return ret;
3514}
3515
3516static void reset_iter_read(struct ftrace_iterator *iter)
3517{
3518 iter->pos = 0;
3519 iter->func_pos = 0;
3520 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3521}
3522
3523static void *t_start(struct seq_file *m, loff_t *pos)
3524{
3525 struct ftrace_iterator *iter = m->private;
3526 void *p = NULL;
3527 loff_t l;
3528
3529 mutex_lock(&ftrace_lock);
3530
3531 if (unlikely(ftrace_disabled))
3532 return NULL;
3533
3534 /*
3535 * If an lseek was done, then reset and start from beginning.
3536 */
3537 if (*pos < iter->pos)
3538 reset_iter_read(iter);
3539
3540 /*
3541 * For set_ftrace_filter reading, if we have the filter
3542 * off, we can short cut and just print out that all
3543 * functions are enabled.
3544 */
3545 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3546 ftrace_hash_empty(iter->hash)) {
3547 iter->func_pos = 1; /* Account for the message */
3548 if (*pos > 0)
3549 return t_mod_start(m, pos);
3550 iter->flags |= FTRACE_ITER_PRINTALL;
3551 /* reset in case of seek/pread */
3552 iter->flags &= ~FTRACE_ITER_PROBE;
3553 return iter;
3554 }
3555
3556 if (iter->flags & FTRACE_ITER_MOD)
3557 return t_mod_start(m, pos);
3558
3559 /*
3560 * Unfortunately, we need to restart at ftrace_pages_start
3561 * every time we let go of the ftrace_mutex. This is because
3562 * those pointers can change without the lock.
3563 */
3564 iter->pg = ftrace_pages_start;
3565 iter->idx = 0;
3566 for (l = 0; l <= *pos; ) {
3567 p = t_func_next(m, &l);
3568 if (!p)
3569 break;
3570 }
3571
3572 if (!p)
3573 return t_mod_start(m, pos);
3574
3575 return iter;
3576}
3577
3578static void t_stop(struct seq_file *m, void *p)
3579{
3580 mutex_unlock(&ftrace_lock);
3581}
3582
3583void * __weak
3584arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3585{
3586 return NULL;
3587}
3588
3589static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3590 struct dyn_ftrace *rec)
3591{
3592 void *ptr;
3593
3594 ptr = arch_ftrace_trampoline_func(ops, rec);
3595 if (ptr)
3596 seq_printf(m, " ->%pS", ptr);
3597}
3598
3599static int t_show(struct seq_file *m, void *v)
3600{
3601 struct ftrace_iterator *iter = m->private;
3602 struct dyn_ftrace *rec;
3603
3604 if (iter->flags & FTRACE_ITER_PROBE)
3605 return t_probe_show(m, iter);
3606
3607 if (iter->flags & FTRACE_ITER_MOD)
3608 return t_mod_show(m, iter);
3609
3610 if (iter->flags & FTRACE_ITER_PRINTALL) {
3611 if (iter->flags & FTRACE_ITER_NOTRACE)
3612 seq_puts(m, "#### no functions disabled ####\n");
3613 else
3614 seq_puts(m, "#### all functions enabled ####\n");
3615 return 0;
3616 }
3617
3618 rec = iter->func;
3619
3620 if (!rec)
3621 return 0;
3622
3623 seq_printf(m, "%ps", (void *)rec->ip);
3624 if (iter->flags & FTRACE_ITER_ENABLED) {
3625 struct ftrace_ops *ops;
3626
3627 seq_printf(m, " (%ld)%s%s%s",
3628 ftrace_rec_count(rec),
3629 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3630 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3631 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3632 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3633 ops = ftrace_find_tramp_ops_any(rec);
3634 if (ops) {
3635 do {
3636 seq_printf(m, "\ttramp: %pS (%pS)",
3637 (void *)ops->trampoline,
3638 (void *)ops->func);
3639 add_trampoline_func(m, ops, rec);
3640 ops = ftrace_find_tramp_ops_next(rec, ops);
3641 } while (ops);
3642 } else
3643 seq_puts(m, "\ttramp: ERROR!");
3644 } else {
3645 add_trampoline_func(m, NULL, rec);
3646 }
3647 if (rec->flags & FTRACE_FL_DIRECT) {
3648 unsigned long direct;
3649
3650 direct = ftrace_find_rec_direct(rec->ip);
3651 if (direct)
3652 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3653 }
3654 }
3655
3656 seq_putc(m, '\n');
3657
3658 return 0;
3659}
3660
3661static const struct seq_operations show_ftrace_seq_ops = {
3662 .start = t_start,
3663 .next = t_next,
3664 .stop = t_stop,
3665 .show = t_show,
3666};
3667
3668static int
3669ftrace_avail_open(struct inode *inode, struct file *file)
3670{
3671 struct ftrace_iterator *iter;
3672 int ret;
3673
3674 ret = security_locked_down(LOCKDOWN_TRACEFS);
3675 if (ret)
3676 return ret;
3677
3678 if (unlikely(ftrace_disabled))
3679 return -ENODEV;
3680
3681 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3682 if (!iter)
3683 return -ENOMEM;
3684
3685 iter->pg = ftrace_pages_start;
3686 iter->ops = &global_ops;
3687
3688 return 0;
3689}
3690
3691static int
3692ftrace_enabled_open(struct inode *inode, struct file *file)
3693{
3694 struct ftrace_iterator *iter;
3695
3696 /*
3697 * This shows us what functions are currently being
3698 * traced and by what. Not sure if we want lockdown
3699 * to hide such critical information for an admin.
3700 * Although, perhaps it can show information we don't
3701 * want people to see, but if something is tracing
3702 * something, we probably want to know about it.
3703 */
3704
3705 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3706 if (!iter)
3707 return -ENOMEM;
3708
3709 iter->pg = ftrace_pages_start;
3710 iter->flags = FTRACE_ITER_ENABLED;
3711 iter->ops = &global_ops;
3712
3713 return 0;
3714}
3715
3716/**
3717 * ftrace_regex_open - initialize function tracer filter files
3718 * @ops: The ftrace_ops that hold the hash filters
3719 * @flag: The type of filter to process
3720 * @inode: The inode, usually passed in to your open routine
3721 * @file: The file, usually passed in to your open routine
3722 *
3723 * ftrace_regex_open() initializes the filter files for the
3724 * @ops. Depending on @flag it may process the filter hash or
3725 * the notrace hash of @ops. With this called from the open
3726 * routine, you can use ftrace_filter_write() for the write
3727 * routine if @flag has FTRACE_ITER_FILTER set, or
3728 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3729 * tracing_lseek() should be used as the lseek routine, and
3730 * release must call ftrace_regex_release().
3731 */
3732int
3733ftrace_regex_open(struct ftrace_ops *ops, int flag,
3734 struct inode *inode, struct file *file)
3735{
3736 struct ftrace_iterator *iter;
3737 struct ftrace_hash *hash;
3738 struct list_head *mod_head;
3739 struct trace_array *tr = ops->private;
3740 int ret = -ENOMEM;
3741
3742 ftrace_ops_init(ops);
3743
3744 if (unlikely(ftrace_disabled))
3745 return -ENODEV;
3746
3747 if (tracing_check_open_get_tr(tr))
3748 return -ENODEV;
3749
3750 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3751 if (!iter)
3752 goto out;
3753
3754 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3755 goto out;
3756
3757 iter->ops = ops;
3758 iter->flags = flag;
3759 iter->tr = tr;
3760
3761 mutex_lock(&ops->func_hash->regex_lock);
3762
3763 if (flag & FTRACE_ITER_NOTRACE) {
3764 hash = ops->func_hash->notrace_hash;
3765 mod_head = tr ? &tr->mod_notrace : NULL;
3766 } else {
3767 hash = ops->func_hash->filter_hash;
3768 mod_head = tr ? &tr->mod_trace : NULL;
3769 }
3770
3771 iter->mod_list = mod_head;
3772
3773 if (file->f_mode & FMODE_WRITE) {
3774 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3775
3776 if (file->f_flags & O_TRUNC) {
3777 iter->hash = alloc_ftrace_hash(size_bits);
3778 clear_ftrace_mod_list(mod_head);
3779 } else {
3780 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3781 }
3782
3783 if (!iter->hash) {
3784 trace_parser_put(&iter->parser);
3785 goto out_unlock;
3786 }
3787 } else
3788 iter->hash = hash;
3789
3790 ret = 0;
3791
3792 if (file->f_mode & FMODE_READ) {
3793 iter->pg = ftrace_pages_start;
3794
3795 ret = seq_open(file, &show_ftrace_seq_ops);
3796 if (!ret) {
3797 struct seq_file *m = file->private_data;
3798 m->private = iter;
3799 } else {
3800 /* Failed */
3801 free_ftrace_hash(iter->hash);
3802 trace_parser_put(&iter->parser);
3803 }
3804 } else
3805 file->private_data = iter;
3806
3807 out_unlock:
3808 mutex_unlock(&ops->func_hash->regex_lock);
3809
3810 out:
3811 if (ret) {
3812 kfree(iter);
3813 if (tr)
3814 trace_array_put(tr);
3815 }
3816
3817 return ret;
3818}
3819
3820static int
3821ftrace_filter_open(struct inode *inode, struct file *file)
3822{
3823 struct ftrace_ops *ops = inode->i_private;
3824
3825 /* Checks for tracefs lockdown */
3826 return ftrace_regex_open(ops,
3827 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3828 inode, file);
3829}
3830
3831static int
3832ftrace_notrace_open(struct inode *inode, struct file *file)
3833{
3834 struct ftrace_ops *ops = inode->i_private;
3835
3836 /* Checks for tracefs lockdown */
3837 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3838 inode, file);
3839}
3840
3841/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3842struct ftrace_glob {
3843 char *search;
3844 unsigned len;
3845 int type;
3846};
3847
3848/*
3849 * If symbols in an architecture don't correspond exactly to the user-visible
3850 * name of what they represent, it is possible to define this function to
3851 * perform the necessary adjustments.
3852*/
3853char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3854{
3855 return str;
3856}
3857
3858static int ftrace_match(char *str, struct ftrace_glob *g)
3859{
3860 int matched = 0;
3861 int slen;
3862
3863 str = arch_ftrace_match_adjust(str, g->search);
3864
3865 switch (g->type) {
3866 case MATCH_FULL:
3867 if (strcmp(str, g->search) == 0)
3868 matched = 1;
3869 break;
3870 case MATCH_FRONT_ONLY:
3871 if (strncmp(str, g->search, g->len) == 0)
3872 matched = 1;
3873 break;
3874 case MATCH_MIDDLE_ONLY:
3875 if (strstr(str, g->search))
3876 matched = 1;
3877 break;
3878 case MATCH_END_ONLY:
3879 slen = strlen(str);
3880 if (slen >= g->len &&
3881 memcmp(str + slen - g->len, g->search, g->len) == 0)
3882 matched = 1;
3883 break;
3884 case MATCH_GLOB:
3885 if (glob_match(g->search, str))
3886 matched = 1;
3887 break;
3888 }
3889
3890 return matched;
3891}
3892
3893static int
3894enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3895{
3896 struct ftrace_func_entry *entry;
3897 int ret = 0;
3898
3899 entry = ftrace_lookup_ip(hash, rec->ip);
3900 if (clear_filter) {
3901 /* Do nothing if it doesn't exist */
3902 if (!entry)
3903 return 0;
3904
3905 free_hash_entry(hash, entry);
3906 } else {
3907 /* Do nothing if it exists */
3908 if (entry)
3909 return 0;
3910
3911 ret = add_hash_entry(hash, rec->ip);
3912 }
3913 return ret;
3914}
3915
3916static int
3917add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3918 int clear_filter)
3919{
3920 long index = simple_strtoul(func_g->search, NULL, 0);
3921 struct ftrace_page *pg;
3922 struct dyn_ftrace *rec;
3923
3924 /* The index starts at 1 */
3925 if (--index < 0)
3926 return 0;
3927
3928 do_for_each_ftrace_rec(pg, rec) {
3929 if (pg->index <= index) {
3930 index -= pg->index;
3931 /* this is a double loop, break goes to the next page */
3932 break;
3933 }
3934 rec = &pg->records[index];
3935 enter_record(hash, rec, clear_filter);
3936 return 1;
3937 } while_for_each_ftrace_rec();
3938 return 0;
3939}
3940
3941static int
3942ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3943 struct ftrace_glob *mod_g, int exclude_mod)
3944{
3945 char str[KSYM_SYMBOL_LEN];
3946 char *modname;
3947
3948 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3949
3950 if (mod_g) {
3951 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3952
3953 /* blank module name to match all modules */
3954 if (!mod_g->len) {
3955 /* blank module globbing: modname xor exclude_mod */
3956 if (!exclude_mod != !modname)
3957 goto func_match;
3958 return 0;
3959 }
3960
3961 /*
3962 * exclude_mod is set to trace everything but the given
3963 * module. If it is set and the module matches, then
3964 * return 0. If it is not set, and the module doesn't match
3965 * also return 0. Otherwise, check the function to see if
3966 * that matches.
3967 */
3968 if (!mod_matches == !exclude_mod)
3969 return 0;
3970func_match:
3971 /* blank search means to match all funcs in the mod */
3972 if (!func_g->len)
3973 return 1;
3974 }
3975
3976 return ftrace_match(str, func_g);
3977}
3978
3979static int
3980match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3981{
3982 struct ftrace_page *pg;
3983 struct dyn_ftrace *rec;
3984 struct ftrace_glob func_g = { .type = MATCH_FULL };
3985 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3986 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3987 int exclude_mod = 0;
3988 int found = 0;
3989 int ret;
3990 int clear_filter = 0;
3991
3992 if (func) {
3993 func_g.type = filter_parse_regex(func, len, &func_g.search,
3994 &clear_filter);
3995 func_g.len = strlen(func_g.search);
3996 }
3997
3998 if (mod) {
3999 mod_g.type = filter_parse_regex(mod, strlen(mod),
4000 &mod_g.search, &exclude_mod);
4001 mod_g.len = strlen(mod_g.search);
4002 }
4003
4004 mutex_lock(&ftrace_lock);
4005
4006 if (unlikely(ftrace_disabled))
4007 goto out_unlock;
4008
4009 if (func_g.type == MATCH_INDEX) {
4010 found = add_rec_by_index(hash, &func_g, clear_filter);
4011 goto out_unlock;
4012 }
4013
4014 do_for_each_ftrace_rec(pg, rec) {
4015
4016 if (rec->flags & FTRACE_FL_DISABLED)
4017 continue;
4018
4019 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4020 ret = enter_record(hash, rec, clear_filter);
4021 if (ret < 0) {
4022 found = ret;
4023 goto out_unlock;
4024 }
4025 found = 1;
4026 }
4027 } while_for_each_ftrace_rec();
4028 out_unlock:
4029 mutex_unlock(&ftrace_lock);
4030
4031 return found;
4032}
4033
4034static int
4035ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4036{
4037 return match_records(hash, buff, len, NULL);
4038}
4039
4040static void ftrace_ops_update_code(struct ftrace_ops *ops,
4041 struct ftrace_ops_hash *old_hash)
4042{
4043 struct ftrace_ops *op;
4044
4045 if (!ftrace_enabled)
4046 return;
4047
4048 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4049 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4050 return;
4051 }
4052
4053 /*
4054 * If this is the shared global_ops filter, then we need to
4055 * check if there is another ops that shares it, is enabled.
4056 * If so, we still need to run the modify code.
4057 */
4058 if (ops->func_hash != &global_ops.local_hash)
4059 return;
4060
4061 do_for_each_ftrace_op(op, ftrace_ops_list) {
4062 if (op->func_hash == &global_ops.local_hash &&
4063 op->flags & FTRACE_OPS_FL_ENABLED) {
4064 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4065 /* Only need to do this once */
4066 return;
4067 }
4068 } while_for_each_ftrace_op(op);
4069}
4070
4071static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4072 struct ftrace_hash **orig_hash,
4073 struct ftrace_hash *hash,
4074 int enable)
4075{
4076 struct ftrace_ops_hash old_hash_ops;
4077 struct ftrace_hash *old_hash;
4078 int ret;
4079
4080 old_hash = *orig_hash;
4081 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4082 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4083 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4084 if (!ret) {
4085 ftrace_ops_update_code(ops, &old_hash_ops);
4086 free_ftrace_hash_rcu(old_hash);
4087 }
4088 return ret;
4089}
4090
4091static bool module_exists(const char *module)
4092{
4093 /* All modules have the symbol __this_module */
4094 static const char this_mod[] = "__this_module";
4095 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4096 unsigned long val;
4097 int n;
4098
4099 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4100
4101 if (n > sizeof(modname) - 1)
4102 return false;
4103
4104 val = module_kallsyms_lookup_name(modname);
4105 return val != 0;
4106}
4107
4108static int cache_mod(struct trace_array *tr,
4109 const char *func, char *module, int enable)
4110{
4111 struct ftrace_mod_load *ftrace_mod, *n;
4112 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4113 int ret;
4114
4115 mutex_lock(&ftrace_lock);
4116
4117 /* We do not cache inverse filters */
4118 if (func[0] == '!') {
4119 func++;
4120 ret = -EINVAL;
4121
4122 /* Look to remove this hash */
4123 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4124 if (strcmp(ftrace_mod->module, module) != 0)
4125 continue;
4126
4127 /* no func matches all */
4128 if (strcmp(func, "*") == 0 ||
4129 (ftrace_mod->func &&
4130 strcmp(ftrace_mod->func, func) == 0)) {
4131 ret = 0;
4132 free_ftrace_mod(ftrace_mod);
4133 continue;
4134 }
4135 }
4136 goto out;
4137 }
4138
4139 ret = -EINVAL;
4140 /* We only care about modules that have not been loaded yet */
4141 if (module_exists(module))
4142 goto out;
4143
4144 /* Save this string off, and execute it when the module is loaded */
4145 ret = ftrace_add_mod(tr, func, module, enable);
4146 out:
4147 mutex_unlock(&ftrace_lock);
4148
4149 return ret;
4150}
4151
4152static int
4153ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4154 int reset, int enable);
4155
4156#ifdef CONFIG_MODULES
4157static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4158 char *mod, bool enable)
4159{
4160 struct ftrace_mod_load *ftrace_mod, *n;
4161 struct ftrace_hash **orig_hash, *new_hash;
4162 LIST_HEAD(process_mods);
4163 char *func;
4164 int ret;
4165
4166 mutex_lock(&ops->func_hash->regex_lock);
4167
4168 if (enable)
4169 orig_hash = &ops->func_hash->filter_hash;
4170 else
4171 orig_hash = &ops->func_hash->notrace_hash;
4172
4173 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4174 *orig_hash);
4175 if (!new_hash)
4176 goto out; /* warn? */
4177
4178 mutex_lock(&ftrace_lock);
4179
4180 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4181
4182 if (strcmp(ftrace_mod->module, mod) != 0)
4183 continue;
4184
4185 if (ftrace_mod->func)
4186 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4187 else
4188 func = kstrdup("*", GFP_KERNEL);
4189
4190 if (!func) /* warn? */
4191 continue;
4192
4193 list_del(&ftrace_mod->list);
4194 list_add(&ftrace_mod->list, &process_mods);
4195
4196 /* Use the newly allocated func, as it may be "*" */
4197 kfree(ftrace_mod->func);
4198 ftrace_mod->func = func;
4199 }
4200
4201 mutex_unlock(&ftrace_lock);
4202
4203 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4204
4205 func = ftrace_mod->func;
4206
4207 /* Grabs ftrace_lock, which is why we have this extra step */
4208 match_records(new_hash, func, strlen(func), mod);
4209 free_ftrace_mod(ftrace_mod);
4210 }
4211
4212 if (enable && list_empty(head))
4213 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4214
4215 mutex_lock(&ftrace_lock);
4216
4217 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4218 new_hash, enable);
4219 mutex_unlock(&ftrace_lock);
4220
4221 out:
4222 mutex_unlock(&ops->func_hash->regex_lock);
4223
4224 free_ftrace_hash(new_hash);
4225}
4226
4227static void process_cached_mods(const char *mod_name)
4228{
4229 struct trace_array *tr;
4230 char *mod;
4231
4232 mod = kstrdup(mod_name, GFP_KERNEL);
4233 if (!mod)
4234 return;
4235
4236 mutex_lock(&trace_types_lock);
4237 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4238 if (!list_empty(&tr->mod_trace))
4239 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4240 if (!list_empty(&tr->mod_notrace))
4241 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4242 }
4243 mutex_unlock(&trace_types_lock);
4244
4245 kfree(mod);
4246}
4247#endif
4248
4249/*
4250 * We register the module command as a template to show others how
4251 * to register the a command as well.
4252 */
4253
4254static int
4255ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4256 char *func_orig, char *cmd, char *module, int enable)
4257{
4258 char *func;
4259 int ret;
4260
4261 /* match_records() modifies func, and we need the original */
4262 func = kstrdup(func_orig, GFP_KERNEL);
4263 if (!func)
4264 return -ENOMEM;
4265
4266 /*
4267 * cmd == 'mod' because we only registered this func
4268 * for the 'mod' ftrace_func_command.
4269 * But if you register one func with multiple commands,
4270 * you can tell which command was used by the cmd
4271 * parameter.
4272 */
4273 ret = match_records(hash, func, strlen(func), module);
4274 kfree(func);
4275
4276 if (!ret)
4277 return cache_mod(tr, func_orig, module, enable);
4278 if (ret < 0)
4279 return ret;
4280 return 0;
4281}
4282
4283static struct ftrace_func_command ftrace_mod_cmd = {
4284 .name = "mod",
4285 .func = ftrace_mod_callback,
4286};
4287
4288static int __init ftrace_mod_cmd_init(void)
4289{
4290 return register_ftrace_command(&ftrace_mod_cmd);
4291}
4292core_initcall(ftrace_mod_cmd_init);
4293
4294static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4295 struct ftrace_ops *op, struct pt_regs *pt_regs)
4296{
4297 struct ftrace_probe_ops *probe_ops;
4298 struct ftrace_func_probe *probe;
4299
4300 probe = container_of(op, struct ftrace_func_probe, ops);
4301 probe_ops = probe->probe_ops;
4302
4303 /*
4304 * Disable preemption for these calls to prevent a RCU grace
4305 * period. This syncs the hash iteration and freeing of items
4306 * on the hash. rcu_read_lock is too dangerous here.
4307 */
4308 preempt_disable_notrace();
4309 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4310 preempt_enable_notrace();
4311}
4312
4313struct ftrace_func_map {
4314 struct ftrace_func_entry entry;
4315 void *data;
4316};
4317
4318struct ftrace_func_mapper {
4319 struct ftrace_hash hash;
4320};
4321
4322/**
4323 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4324 *
4325 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4326 */
4327struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4328{
4329 struct ftrace_hash *hash;
4330
4331 /*
4332 * The mapper is simply a ftrace_hash, but since the entries
4333 * in the hash are not ftrace_func_entry type, we define it
4334 * as a separate structure.
4335 */
4336 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4337 return (struct ftrace_func_mapper *)hash;
4338}
4339
4340/**
4341 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4342 * @mapper: The mapper that has the ip maps
4343 * @ip: the instruction pointer to find the data for
4344 *
4345 * Returns the data mapped to @ip if found otherwise NULL. The return
4346 * is actually the address of the mapper data pointer. The address is
4347 * returned for use cases where the data is no bigger than a long, and
4348 * the user can use the data pointer as its data instead of having to
4349 * allocate more memory for the reference.
4350 */
4351void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4352 unsigned long ip)
4353{
4354 struct ftrace_func_entry *entry;
4355 struct ftrace_func_map *map;
4356
4357 entry = ftrace_lookup_ip(&mapper->hash, ip);
4358 if (!entry)
4359 return NULL;
4360
4361 map = (struct ftrace_func_map *)entry;
4362 return &map->data;
4363}
4364
4365/**
4366 * ftrace_func_mapper_add_ip - Map some data to an ip
4367 * @mapper: The mapper that has the ip maps
4368 * @ip: The instruction pointer address to map @data to
4369 * @data: The data to map to @ip
4370 *
4371 * Returns 0 on succes otherwise an error.
4372 */
4373int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4374 unsigned long ip, void *data)
4375{
4376 struct ftrace_func_entry *entry;
4377 struct ftrace_func_map *map;
4378
4379 entry = ftrace_lookup_ip(&mapper->hash, ip);
4380 if (entry)
4381 return -EBUSY;
4382
4383 map = kmalloc(sizeof(*map), GFP_KERNEL);
4384 if (!map)
4385 return -ENOMEM;
4386
4387 map->entry.ip = ip;
4388 map->data = data;
4389
4390 __add_hash_entry(&mapper->hash, &map->entry);
4391
4392 return 0;
4393}
4394
4395/**
4396 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4397 * @mapper: The mapper that has the ip maps
4398 * @ip: The instruction pointer address to remove the data from
4399 *
4400 * Returns the data if it is found, otherwise NULL.
4401 * Note, if the data pointer is used as the data itself, (see
4402 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4403 * if the data pointer was set to zero.
4404 */
4405void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4406 unsigned long ip)
4407{
4408 struct ftrace_func_entry *entry;
4409 struct ftrace_func_map *map;
4410 void *data;
4411
4412 entry = ftrace_lookup_ip(&mapper->hash, ip);
4413 if (!entry)
4414 return NULL;
4415
4416 map = (struct ftrace_func_map *)entry;
4417 data = map->data;
4418
4419 remove_hash_entry(&mapper->hash, entry);
4420 kfree(entry);
4421
4422 return data;
4423}
4424
4425/**
4426 * free_ftrace_func_mapper - free a mapping of ips and data
4427 * @mapper: The mapper that has the ip maps
4428 * @free_func: A function to be called on each data item.
4429 *
4430 * This is used to free the function mapper. The @free_func is optional
4431 * and can be used if the data needs to be freed as well.
4432 */
4433void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4434 ftrace_mapper_func free_func)
4435{
4436 struct ftrace_func_entry *entry;
4437 struct ftrace_func_map *map;
4438 struct hlist_head *hhd;
4439 int size, i;
4440
4441 if (!mapper)
4442 return;
4443
4444 if (free_func && mapper->hash.count) {
4445 size = 1 << mapper->hash.size_bits;
4446 for (i = 0; i < size; i++) {
4447 hhd = &mapper->hash.buckets[i];
4448 hlist_for_each_entry(entry, hhd, hlist) {
4449 map = (struct ftrace_func_map *)entry;
4450 free_func(map);
4451 }
4452 }
4453 }
4454 free_ftrace_hash(&mapper->hash);
4455}
4456
4457static void release_probe(struct ftrace_func_probe *probe)
4458{
4459 struct ftrace_probe_ops *probe_ops;
4460
4461 mutex_lock(&ftrace_lock);
4462
4463 WARN_ON(probe->ref <= 0);
4464
4465 /* Subtract the ref that was used to protect this instance */
4466 probe->ref--;
4467
4468 if (!probe->ref) {
4469 probe_ops = probe->probe_ops;
4470 /*
4471 * Sending zero as ip tells probe_ops to free
4472 * the probe->data itself
4473 */
4474 if (probe_ops->free)
4475 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4476 list_del(&probe->list);
4477 kfree(probe);
4478 }
4479 mutex_unlock(&ftrace_lock);
4480}
4481
4482static void acquire_probe_locked(struct ftrace_func_probe *probe)
4483{
4484 /*
4485 * Add one ref to keep it from being freed when releasing the
4486 * ftrace_lock mutex.
4487 */
4488 probe->ref++;
4489}
4490
4491int
4492register_ftrace_function_probe(char *glob, struct trace_array *tr,
4493 struct ftrace_probe_ops *probe_ops,
4494 void *data)
4495{
4496 struct ftrace_func_entry *entry;
4497 struct ftrace_func_probe *probe;
4498 struct ftrace_hash **orig_hash;
4499 struct ftrace_hash *old_hash;
4500 struct ftrace_hash *hash;
4501 int count = 0;
4502 int size;
4503 int ret;
4504 int i;
4505
4506 if (WARN_ON(!tr))
4507 return -EINVAL;
4508
4509 /* We do not support '!' for function probes */
4510 if (WARN_ON(glob[0] == '!'))
4511 return -EINVAL;
4512
4513
4514 mutex_lock(&ftrace_lock);
4515 /* Check if the probe_ops is already registered */
4516 list_for_each_entry(probe, &tr->func_probes, list) {
4517 if (probe->probe_ops == probe_ops)
4518 break;
4519 }
4520 if (&probe->list == &tr->func_probes) {
4521 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4522 if (!probe) {
4523 mutex_unlock(&ftrace_lock);
4524 return -ENOMEM;
4525 }
4526 probe->probe_ops = probe_ops;
4527 probe->ops.func = function_trace_probe_call;
4528 probe->tr = tr;
4529 ftrace_ops_init(&probe->ops);
4530 list_add(&probe->list, &tr->func_probes);
4531 }
4532
4533 acquire_probe_locked(probe);
4534
4535 mutex_unlock(&ftrace_lock);
4536
4537 /*
4538 * Note, there's a small window here that the func_hash->filter_hash
4539 * may be NULL or empty. Need to be carefule when reading the loop.
4540 */
4541 mutex_lock(&probe->ops.func_hash->regex_lock);
4542
4543 orig_hash = &probe->ops.func_hash->filter_hash;
4544 old_hash = *orig_hash;
4545 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4546
4547 if (!hash) {
4548 ret = -ENOMEM;
4549 goto out;
4550 }
4551
4552 ret = ftrace_match_records(hash, glob, strlen(glob));
4553
4554 /* Nothing found? */
4555 if (!ret)
4556 ret = -EINVAL;
4557
4558 if (ret < 0)
4559 goto out;
4560
4561 size = 1 << hash->size_bits;
4562 for (i = 0; i < size; i++) {
4563 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4564 if (ftrace_lookup_ip(old_hash, entry->ip))
4565 continue;
4566 /*
4567 * The caller might want to do something special
4568 * for each function we find. We call the callback
4569 * to give the caller an opportunity to do so.
4570 */
4571 if (probe_ops->init) {
4572 ret = probe_ops->init(probe_ops, tr,
4573 entry->ip, data,
4574 &probe->data);
4575 if (ret < 0) {
4576 if (probe_ops->free && count)
4577 probe_ops->free(probe_ops, tr,
4578 0, probe->data);
4579 probe->data = NULL;
4580 goto out;
4581 }
4582 }
4583 count++;
4584 }
4585 }
4586
4587 mutex_lock(&ftrace_lock);
4588
4589 if (!count) {
4590 /* Nothing was added? */
4591 ret = -EINVAL;
4592 goto out_unlock;
4593 }
4594
4595 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4596 hash, 1);
4597 if (ret < 0)
4598 goto err_unlock;
4599
4600 /* One ref for each new function traced */
4601 probe->ref += count;
4602
4603 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4604 ret = ftrace_startup(&probe->ops, 0);
4605
4606 out_unlock:
4607 mutex_unlock(&ftrace_lock);
4608
4609 if (!ret)
4610 ret = count;
4611 out:
4612 mutex_unlock(&probe->ops.func_hash->regex_lock);
4613 free_ftrace_hash(hash);
4614
4615 release_probe(probe);
4616
4617 return ret;
4618
4619 err_unlock:
4620 if (!probe_ops->free || !count)
4621 goto out_unlock;
4622
4623 /* Failed to do the move, need to call the free functions */
4624 for (i = 0; i < size; i++) {
4625 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4626 if (ftrace_lookup_ip(old_hash, entry->ip))
4627 continue;
4628 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4629 }
4630 }
4631 goto out_unlock;
4632}
4633
4634int
4635unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4636 struct ftrace_probe_ops *probe_ops)
4637{
4638 struct ftrace_ops_hash old_hash_ops;
4639 struct ftrace_func_entry *entry;
4640 struct ftrace_func_probe *probe;
4641 struct ftrace_glob func_g;
4642 struct ftrace_hash **orig_hash;
4643 struct ftrace_hash *old_hash;
4644 struct ftrace_hash *hash = NULL;
4645 struct hlist_node *tmp;
4646 struct hlist_head hhd;
4647 char str[KSYM_SYMBOL_LEN];
4648 int count = 0;
4649 int i, ret = -ENODEV;
4650 int size;
4651
4652 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4653 func_g.search = NULL;
4654 else {
4655 int not;
4656
4657 func_g.type = filter_parse_regex(glob, strlen(glob),
4658 &func_g.search, ¬);
4659 func_g.len = strlen(func_g.search);
4660
4661 /* we do not support '!' for function probes */
4662 if (WARN_ON(not))
4663 return -EINVAL;
4664 }
4665
4666 mutex_lock(&ftrace_lock);
4667 /* Check if the probe_ops is already registered */
4668 list_for_each_entry(probe, &tr->func_probes, list) {
4669 if (probe->probe_ops == probe_ops)
4670 break;
4671 }
4672 if (&probe->list == &tr->func_probes)
4673 goto err_unlock_ftrace;
4674
4675 ret = -EINVAL;
4676 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4677 goto err_unlock_ftrace;
4678
4679 acquire_probe_locked(probe);
4680
4681 mutex_unlock(&ftrace_lock);
4682
4683 mutex_lock(&probe->ops.func_hash->regex_lock);
4684
4685 orig_hash = &probe->ops.func_hash->filter_hash;
4686 old_hash = *orig_hash;
4687
4688 if (ftrace_hash_empty(old_hash))
4689 goto out_unlock;
4690
4691 old_hash_ops.filter_hash = old_hash;
4692 /* Probes only have filters */
4693 old_hash_ops.notrace_hash = NULL;
4694
4695 ret = -ENOMEM;
4696 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4697 if (!hash)
4698 goto out_unlock;
4699
4700 INIT_HLIST_HEAD(&hhd);
4701
4702 size = 1 << hash->size_bits;
4703 for (i = 0; i < size; i++) {
4704 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4705
4706 if (func_g.search) {
4707 kallsyms_lookup(entry->ip, NULL, NULL,
4708 NULL, str);
4709 if (!ftrace_match(str, &func_g))
4710 continue;
4711 }
4712 count++;
4713 remove_hash_entry(hash, entry);
4714 hlist_add_head(&entry->hlist, &hhd);
4715 }
4716 }
4717
4718 /* Nothing found? */
4719 if (!count) {
4720 ret = -EINVAL;
4721 goto out_unlock;
4722 }
4723
4724 mutex_lock(&ftrace_lock);
4725
4726 WARN_ON(probe->ref < count);
4727
4728 probe->ref -= count;
4729
4730 if (ftrace_hash_empty(hash))
4731 ftrace_shutdown(&probe->ops, 0);
4732
4733 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4734 hash, 1);
4735
4736 /* still need to update the function call sites */
4737 if (ftrace_enabled && !ftrace_hash_empty(hash))
4738 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4739 &old_hash_ops);
4740 synchronize_rcu();
4741
4742 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4743 hlist_del(&entry->hlist);
4744 if (probe_ops->free)
4745 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4746 kfree(entry);
4747 }
4748 mutex_unlock(&ftrace_lock);
4749
4750 out_unlock:
4751 mutex_unlock(&probe->ops.func_hash->regex_lock);
4752 free_ftrace_hash(hash);
4753
4754 release_probe(probe);
4755
4756 return ret;
4757
4758 err_unlock_ftrace:
4759 mutex_unlock(&ftrace_lock);
4760 return ret;
4761}
4762
4763void clear_ftrace_function_probes(struct trace_array *tr)
4764{
4765 struct ftrace_func_probe *probe, *n;
4766
4767 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4768 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4769}
4770
4771static LIST_HEAD(ftrace_commands);
4772static DEFINE_MUTEX(ftrace_cmd_mutex);
4773
4774/*
4775 * Currently we only register ftrace commands from __init, so mark this
4776 * __init too.
4777 */
4778__init int register_ftrace_command(struct ftrace_func_command *cmd)
4779{
4780 struct ftrace_func_command *p;
4781 int ret = 0;
4782
4783 mutex_lock(&ftrace_cmd_mutex);
4784 list_for_each_entry(p, &ftrace_commands, list) {
4785 if (strcmp(cmd->name, p->name) == 0) {
4786 ret = -EBUSY;
4787 goto out_unlock;
4788 }
4789 }
4790 list_add(&cmd->list, &ftrace_commands);
4791 out_unlock:
4792 mutex_unlock(&ftrace_cmd_mutex);
4793
4794 return ret;
4795}
4796
4797/*
4798 * Currently we only unregister ftrace commands from __init, so mark
4799 * this __init too.
4800 */
4801__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4802{
4803 struct ftrace_func_command *p, *n;
4804 int ret = -ENODEV;
4805
4806 mutex_lock(&ftrace_cmd_mutex);
4807 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4808 if (strcmp(cmd->name, p->name) == 0) {
4809 ret = 0;
4810 list_del_init(&p->list);
4811 goto out_unlock;
4812 }
4813 }
4814 out_unlock:
4815 mutex_unlock(&ftrace_cmd_mutex);
4816
4817 return ret;
4818}
4819
4820static int ftrace_process_regex(struct ftrace_iterator *iter,
4821 char *buff, int len, int enable)
4822{
4823 struct ftrace_hash *hash = iter->hash;
4824 struct trace_array *tr = iter->ops->private;
4825 char *func, *command, *next = buff;
4826 struct ftrace_func_command *p;
4827 int ret = -EINVAL;
4828
4829 func = strsep(&next, ":");
4830
4831 if (!next) {
4832 ret = ftrace_match_records(hash, func, len);
4833 if (!ret)
4834 ret = -EINVAL;
4835 if (ret < 0)
4836 return ret;
4837 return 0;
4838 }
4839
4840 /* command found */
4841
4842 command = strsep(&next, ":");
4843
4844 mutex_lock(&ftrace_cmd_mutex);
4845 list_for_each_entry(p, &ftrace_commands, list) {
4846 if (strcmp(p->name, command) == 0) {
4847 ret = p->func(tr, hash, func, command, next, enable);
4848 goto out_unlock;
4849 }
4850 }
4851 out_unlock:
4852 mutex_unlock(&ftrace_cmd_mutex);
4853
4854 return ret;
4855}
4856
4857static ssize_t
4858ftrace_regex_write(struct file *file, const char __user *ubuf,
4859 size_t cnt, loff_t *ppos, int enable)
4860{
4861 struct ftrace_iterator *iter;
4862 struct trace_parser *parser;
4863 ssize_t ret, read;
4864
4865 if (!cnt)
4866 return 0;
4867
4868 if (file->f_mode & FMODE_READ) {
4869 struct seq_file *m = file->private_data;
4870 iter = m->private;
4871 } else
4872 iter = file->private_data;
4873
4874 if (unlikely(ftrace_disabled))
4875 return -ENODEV;
4876
4877 /* iter->hash is a local copy, so we don't need regex_lock */
4878
4879 parser = &iter->parser;
4880 read = trace_get_user(parser, ubuf, cnt, ppos);
4881
4882 if (read >= 0 && trace_parser_loaded(parser) &&
4883 !trace_parser_cont(parser)) {
4884 ret = ftrace_process_regex(iter, parser->buffer,
4885 parser->idx, enable);
4886 trace_parser_clear(parser);
4887 if (ret < 0)
4888 goto out;
4889 }
4890
4891 ret = read;
4892 out:
4893 return ret;
4894}
4895
4896ssize_t
4897ftrace_filter_write(struct file *file, const char __user *ubuf,
4898 size_t cnt, loff_t *ppos)
4899{
4900 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4901}
4902
4903ssize_t
4904ftrace_notrace_write(struct file *file, const char __user *ubuf,
4905 size_t cnt, loff_t *ppos)
4906{
4907 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4908}
4909
4910static int
4911ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4912{
4913 struct ftrace_func_entry *entry;
4914
4915 if (!ftrace_location(ip))
4916 return -EINVAL;
4917
4918 if (remove) {
4919 entry = ftrace_lookup_ip(hash, ip);
4920 if (!entry)
4921 return -ENOENT;
4922 free_hash_entry(hash, entry);
4923 return 0;
4924 }
4925
4926 return add_hash_entry(hash, ip);
4927}
4928
4929static int
4930ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4931 unsigned long ip, int remove, int reset, int enable)
4932{
4933 struct ftrace_hash **orig_hash;
4934 struct ftrace_hash *hash;
4935 int ret;
4936
4937 if (unlikely(ftrace_disabled))
4938 return -ENODEV;
4939
4940 mutex_lock(&ops->func_hash->regex_lock);
4941
4942 if (enable)
4943 orig_hash = &ops->func_hash->filter_hash;
4944 else
4945 orig_hash = &ops->func_hash->notrace_hash;
4946
4947 if (reset)
4948 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4949 else
4950 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4951
4952 if (!hash) {
4953 ret = -ENOMEM;
4954 goto out_regex_unlock;
4955 }
4956
4957 if (buf && !ftrace_match_records(hash, buf, len)) {
4958 ret = -EINVAL;
4959 goto out_regex_unlock;
4960 }
4961 if (ip) {
4962 ret = ftrace_match_addr(hash, ip, remove);
4963 if (ret < 0)
4964 goto out_regex_unlock;
4965 }
4966
4967 mutex_lock(&ftrace_lock);
4968 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4969 mutex_unlock(&ftrace_lock);
4970
4971 out_regex_unlock:
4972 mutex_unlock(&ops->func_hash->regex_lock);
4973
4974 free_ftrace_hash(hash);
4975 return ret;
4976}
4977
4978static int
4979ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4980 int reset, int enable)
4981{
4982 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4983}
4984
4985#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
4986
4987struct ftrace_direct_func {
4988 struct list_head next;
4989 unsigned long addr;
4990 int count;
4991};
4992
4993static LIST_HEAD(ftrace_direct_funcs);
4994
4995/**
4996 * ftrace_find_direct_func - test an address if it is a registered direct caller
4997 * @addr: The address of a registered direct caller
4998 *
4999 * This searches to see if a ftrace direct caller has been registered
5000 * at a specific address, and if so, it returns a descriptor for it.
5001 *
5002 * This can be used by architecture code to see if an address is
5003 * a direct caller (trampoline) attached to a fentry/mcount location.
5004 * This is useful for the function_graph tracer, as it may need to
5005 * do adjustments if it traced a location that also has a direct
5006 * trampoline attached to it.
5007 */
5008struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5009{
5010 struct ftrace_direct_func *entry;
5011 bool found = false;
5012
5013 /* May be called by fgraph trampoline (protected by rcu tasks) */
5014 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5015 if (entry->addr == addr) {
5016 found = true;
5017 break;
5018 }
5019 }
5020 if (found)
5021 return entry;
5022
5023 return NULL;
5024}
5025
5026/**
5027 * register_ftrace_direct - Call a custom trampoline directly
5028 * @ip: The address of the nop at the beginning of a function
5029 * @addr: The address of the trampoline to call at @ip
5030 *
5031 * This is used to connect a direct call from the nop location (@ip)
5032 * at the start of ftrace traced functions. The location that it calls
5033 * (@addr) must be able to handle a direct call, and save the parameters
5034 * of the function being traced, and restore them (or inject new ones
5035 * if needed), before returning.
5036 *
5037 * Returns:
5038 * 0 on success
5039 * -EBUSY - Another direct function is already attached (there can be only one)
5040 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5041 * -ENOMEM - There was an allocation failure.
5042 */
5043int register_ftrace_direct(unsigned long ip, unsigned long addr)
5044{
5045 struct ftrace_direct_func *direct;
5046 struct ftrace_func_entry *entry;
5047 struct ftrace_hash *free_hash = NULL;
5048 struct dyn_ftrace *rec;
5049 int ret = -EBUSY;
5050
5051 mutex_lock(&direct_mutex);
5052
5053 /* See if there's a direct function at @ip already */
5054 if (ftrace_find_rec_direct(ip))
5055 goto out_unlock;
5056
5057 ret = -ENODEV;
5058 rec = lookup_rec(ip, ip);
5059 if (!rec)
5060 goto out_unlock;
5061
5062 /*
5063 * Check if the rec says it has a direct call but we didn't
5064 * find one earlier?
5065 */
5066 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5067 goto out_unlock;
5068
5069 /* Make sure the ip points to the exact record */
5070 if (ip != rec->ip) {
5071 ip = rec->ip;
5072 /* Need to check this ip for a direct. */
5073 if (ftrace_find_rec_direct(ip))
5074 goto out_unlock;
5075 }
5076
5077 ret = -ENOMEM;
5078 if (ftrace_hash_empty(direct_functions) ||
5079 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5080 struct ftrace_hash *new_hash;
5081 int size = ftrace_hash_empty(direct_functions) ? 0 :
5082 direct_functions->count + 1;
5083
5084 if (size < 32)
5085 size = 32;
5086
5087 new_hash = dup_hash(direct_functions, size);
5088 if (!new_hash)
5089 goto out_unlock;
5090
5091 free_hash = direct_functions;
5092 direct_functions = new_hash;
5093 }
5094
5095 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5096 if (!entry)
5097 goto out_unlock;
5098
5099 direct = ftrace_find_direct_func(addr);
5100 if (!direct) {
5101 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5102 if (!direct) {
5103 kfree(entry);
5104 goto out_unlock;
5105 }
5106 direct->addr = addr;
5107 direct->count = 0;
5108 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5109 ftrace_direct_func_count++;
5110 }
5111
5112 entry->ip = ip;
5113 entry->direct = addr;
5114 __add_hash_entry(direct_functions, entry);
5115
5116 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5117 if (ret)
5118 remove_hash_entry(direct_functions, entry);
5119
5120 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5121 ret = register_ftrace_function(&direct_ops);
5122 if (ret)
5123 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5124 }
5125
5126 if (ret) {
5127 kfree(entry);
5128 if (!direct->count) {
5129 list_del_rcu(&direct->next);
5130 synchronize_rcu_tasks();
5131 kfree(direct);
5132 if (free_hash)
5133 free_ftrace_hash(free_hash);
5134 free_hash = NULL;
5135 ftrace_direct_func_count--;
5136 }
5137 } else {
5138 direct->count++;
5139 }
5140 out_unlock:
5141 mutex_unlock(&direct_mutex);
5142
5143 if (free_hash) {
5144 synchronize_rcu_tasks();
5145 free_ftrace_hash(free_hash);
5146 }
5147
5148 return ret;
5149}
5150EXPORT_SYMBOL_GPL(register_ftrace_direct);
5151
5152static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5153 struct dyn_ftrace **recp)
5154{
5155 struct ftrace_func_entry *entry;
5156 struct dyn_ftrace *rec;
5157
5158 rec = lookup_rec(*ip, *ip);
5159 if (!rec)
5160 return NULL;
5161
5162 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5163 if (!entry) {
5164 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5165 return NULL;
5166 }
5167
5168 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5169
5170 /* Passed in ip just needs to be on the call site */
5171 *ip = rec->ip;
5172
5173 if (recp)
5174 *recp = rec;
5175
5176 return entry;
5177}
5178
5179int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5180{
5181 struct ftrace_direct_func *direct;
5182 struct ftrace_func_entry *entry;
5183 int ret = -ENODEV;
5184
5185 mutex_lock(&direct_mutex);
5186
5187 entry = find_direct_entry(&ip, NULL);
5188 if (!entry)
5189 goto out_unlock;
5190
5191 if (direct_functions->count == 1)
5192 unregister_ftrace_function(&direct_ops);
5193
5194 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5195
5196 WARN_ON(ret);
5197
5198 remove_hash_entry(direct_functions, entry);
5199
5200 direct = ftrace_find_direct_func(addr);
5201 if (!WARN_ON(!direct)) {
5202 /* This is the good path (see the ! before WARN) */
5203 direct->count--;
5204 WARN_ON(direct->count < 0);
5205 if (!direct->count) {
5206 list_del_rcu(&direct->next);
5207 synchronize_rcu_tasks();
5208 kfree(direct);
5209 kfree(entry);
5210 ftrace_direct_func_count--;
5211 }
5212 }
5213 out_unlock:
5214 mutex_unlock(&direct_mutex);
5215
5216 return ret;
5217}
5218EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5219
5220static struct ftrace_ops stub_ops = {
5221 .func = ftrace_stub,
5222};
5223
5224/**
5225 * ftrace_modify_direct_caller - modify ftrace nop directly
5226 * @entry: The ftrace hash entry of the direct helper for @rec
5227 * @rec: The record representing the function site to patch
5228 * @old_addr: The location that the site at @rec->ip currently calls
5229 * @new_addr: The location that the site at @rec->ip should call
5230 *
5231 * An architecture may overwrite this function to optimize the
5232 * changing of the direct callback on an ftrace nop location.
5233 * This is called with the ftrace_lock mutex held, and no other
5234 * ftrace callbacks are on the associated record (@rec). Thus,
5235 * it is safe to modify the ftrace record, where it should be
5236 * currently calling @old_addr directly, to call @new_addr.
5237 *
5238 * Safety checks should be made to make sure that the code at
5239 * @rec->ip is currently calling @old_addr. And this must
5240 * also update entry->direct to @new_addr.
5241 */
5242int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5243 struct dyn_ftrace *rec,
5244 unsigned long old_addr,
5245 unsigned long new_addr)
5246{
5247 unsigned long ip = rec->ip;
5248 int ret;
5249
5250 /*
5251 * The ftrace_lock was used to determine if the record
5252 * had more than one registered user to it. If it did,
5253 * we needed to prevent that from changing to do the quick
5254 * switch. But if it did not (only a direct caller was attached)
5255 * then this function is called. But this function can deal
5256 * with attached callers to the rec that we care about, and
5257 * since this function uses standard ftrace calls that take
5258 * the ftrace_lock mutex, we need to release it.
5259 */
5260 mutex_unlock(&ftrace_lock);
5261
5262 /*
5263 * By setting a stub function at the same address, we force
5264 * the code to call the iterator and the direct_ops helper.
5265 * This means that @ip does not call the direct call, and
5266 * we can simply modify it.
5267 */
5268 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5269 if (ret)
5270 goto out_lock;
5271
5272 ret = register_ftrace_function(&stub_ops);
5273 if (ret) {
5274 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5275 goto out_lock;
5276 }
5277
5278 entry->direct = new_addr;
5279
5280 /*
5281 * By removing the stub, we put back the direct call, calling
5282 * the @new_addr.
5283 */
5284 unregister_ftrace_function(&stub_ops);
5285 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5286
5287 out_lock:
5288 mutex_lock(&ftrace_lock);
5289
5290 return ret;
5291}
5292
5293/**
5294 * modify_ftrace_direct - Modify an existing direct call to call something else
5295 * @ip: The instruction pointer to modify
5296 * @old_addr: The address that the current @ip calls directly
5297 * @new_addr: The address that the @ip should call
5298 *
5299 * This modifies a ftrace direct caller at an instruction pointer without
5300 * having to disable it first. The direct call will switch over to the
5301 * @new_addr without missing anything.
5302 *
5303 * Returns: zero on success. Non zero on error, which includes:
5304 * -ENODEV : the @ip given has no direct caller attached
5305 * -EINVAL : the @old_addr does not match the current direct caller
5306 */
5307int modify_ftrace_direct(unsigned long ip,
5308 unsigned long old_addr, unsigned long new_addr)
5309{
5310 struct ftrace_func_entry *entry;
5311 struct dyn_ftrace *rec;
5312 int ret = -ENODEV;
5313
5314 mutex_lock(&direct_mutex);
5315
5316 mutex_lock(&ftrace_lock);
5317 entry = find_direct_entry(&ip, &rec);
5318 if (!entry)
5319 goto out_unlock;
5320
5321 ret = -EINVAL;
5322 if (entry->direct != old_addr)
5323 goto out_unlock;
5324
5325 /*
5326 * If there's no other ftrace callback on the rec->ip location,
5327 * then it can be changed directly by the architecture.
5328 * If there is another caller, then we just need to change the
5329 * direct caller helper to point to @new_addr.
5330 */
5331 if (ftrace_rec_count(rec) == 1) {
5332 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5333 } else {
5334 entry->direct = new_addr;
5335 ret = 0;
5336 }
5337
5338 out_unlock:
5339 mutex_unlock(&ftrace_lock);
5340 mutex_unlock(&direct_mutex);
5341 return ret;
5342}
5343EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5344#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5345
5346/**
5347 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5348 * @ops - the ops to set the filter with
5349 * @ip - the address to add to or remove from the filter.
5350 * @remove - non zero to remove the ip from the filter
5351 * @reset - non zero to reset all filters before applying this filter.
5352 *
5353 * Filters denote which functions should be enabled when tracing is enabled
5354 * If @ip is NULL, it failes to update filter.
5355 */
5356int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5357 int remove, int reset)
5358{
5359 ftrace_ops_init(ops);
5360 return ftrace_set_addr(ops, ip, remove, reset, 1);
5361}
5362EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5363
5364/**
5365 * ftrace_ops_set_global_filter - setup ops to use global filters
5366 * @ops - the ops which will use the global filters
5367 *
5368 * ftrace users who need global function trace filtering should call this.
5369 * It can set the global filter only if ops were not initialized before.
5370 */
5371void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5372{
5373 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5374 return;
5375
5376 ftrace_ops_init(ops);
5377 ops->func_hash = &global_ops.local_hash;
5378}
5379EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5380
5381static int
5382ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5383 int reset, int enable)
5384{
5385 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5386}
5387
5388/**
5389 * ftrace_set_filter - set a function to filter on in ftrace
5390 * @ops - the ops to set the filter with
5391 * @buf - the string that holds the function filter text.
5392 * @len - the length of the string.
5393 * @reset - non zero to reset all filters before applying this filter.
5394 *
5395 * Filters denote which functions should be enabled when tracing is enabled.
5396 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5397 */
5398int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5399 int len, int reset)
5400{
5401 ftrace_ops_init(ops);
5402 return ftrace_set_regex(ops, buf, len, reset, 1);
5403}
5404EXPORT_SYMBOL_GPL(ftrace_set_filter);
5405
5406/**
5407 * ftrace_set_notrace - set a function to not trace in ftrace
5408 * @ops - the ops to set the notrace filter with
5409 * @buf - the string that holds the function notrace text.
5410 * @len - the length of the string.
5411 * @reset - non zero to reset all filters before applying this filter.
5412 *
5413 * Notrace Filters denote which functions should not be enabled when tracing
5414 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5415 * for tracing.
5416 */
5417int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5418 int len, int reset)
5419{
5420 ftrace_ops_init(ops);
5421 return ftrace_set_regex(ops, buf, len, reset, 0);
5422}
5423EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5424/**
5425 * ftrace_set_global_filter - set a function to filter on with global tracers
5426 * @buf - the string that holds the function filter text.
5427 * @len - the length of the string.
5428 * @reset - non zero to reset all filters before applying this filter.
5429 *
5430 * Filters denote which functions should be enabled when tracing is enabled.
5431 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5432 */
5433void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5434{
5435 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5436}
5437EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5438
5439/**
5440 * ftrace_set_global_notrace - set a function to not trace with global tracers
5441 * @buf - the string that holds the function notrace text.
5442 * @len - the length of the string.
5443 * @reset - non zero to reset all filters before applying this filter.
5444 *
5445 * Notrace Filters denote which functions should not be enabled when tracing
5446 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5447 * for tracing.
5448 */
5449void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5450{
5451 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5452}
5453EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5454
5455/*
5456 * command line interface to allow users to set filters on boot up.
5457 */
5458#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5459static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5460static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5461
5462/* Used by function selftest to not test if filter is set */
5463bool ftrace_filter_param __initdata;
5464
5465static int __init set_ftrace_notrace(char *str)
5466{
5467 ftrace_filter_param = true;
5468 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5469 return 1;
5470}
5471__setup("ftrace_notrace=", set_ftrace_notrace);
5472
5473static int __init set_ftrace_filter(char *str)
5474{
5475 ftrace_filter_param = true;
5476 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5477 return 1;
5478}
5479__setup("ftrace_filter=", set_ftrace_filter);
5480
5481#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5482static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5483static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5484static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5485
5486static int __init set_graph_function(char *str)
5487{
5488 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5489 return 1;
5490}
5491__setup("ftrace_graph_filter=", set_graph_function);
5492
5493static int __init set_graph_notrace_function(char *str)
5494{
5495 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5496 return 1;
5497}
5498__setup("ftrace_graph_notrace=", set_graph_notrace_function);
5499
5500static int __init set_graph_max_depth_function(char *str)
5501{
5502 if (!str)
5503 return 0;
5504 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5505 return 1;
5506}
5507__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5508
5509static void __init set_ftrace_early_graph(char *buf, int enable)
5510{
5511 int ret;
5512 char *func;
5513 struct ftrace_hash *hash;
5514
5515 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5516 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5517 return;
5518
5519 while (buf) {
5520 func = strsep(&buf, ",");
5521 /* we allow only one expression at a time */
5522 ret = ftrace_graph_set_hash(hash, func);
5523 if (ret)
5524 printk(KERN_DEBUG "ftrace: function %s not "
5525 "traceable\n", func);
5526 }
5527
5528 if (enable)
5529 ftrace_graph_hash = hash;
5530 else
5531 ftrace_graph_notrace_hash = hash;
5532}
5533#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5534
5535void __init
5536ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5537{
5538 char *func;
5539
5540 ftrace_ops_init(ops);
5541
5542 while (buf) {
5543 func = strsep(&buf, ",");
5544 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5545 }
5546}
5547
5548static void __init set_ftrace_early_filters(void)
5549{
5550 if (ftrace_filter_buf[0])
5551 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5552 if (ftrace_notrace_buf[0])
5553 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5554#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5555 if (ftrace_graph_buf[0])
5556 set_ftrace_early_graph(ftrace_graph_buf, 1);
5557 if (ftrace_graph_notrace_buf[0])
5558 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5559#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5560}
5561
5562int ftrace_regex_release(struct inode *inode, struct file *file)
5563{
5564 struct seq_file *m = (struct seq_file *)file->private_data;
5565 struct ftrace_iterator *iter;
5566 struct ftrace_hash **orig_hash;
5567 struct trace_parser *parser;
5568 int filter_hash;
5569 int ret;
5570
5571 if (file->f_mode & FMODE_READ) {
5572 iter = m->private;
5573 seq_release(inode, file);
5574 } else
5575 iter = file->private_data;
5576
5577 parser = &iter->parser;
5578 if (trace_parser_loaded(parser)) {
5579 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5580 }
5581
5582 trace_parser_put(parser);
5583
5584 mutex_lock(&iter->ops->func_hash->regex_lock);
5585
5586 if (file->f_mode & FMODE_WRITE) {
5587 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5588
5589 if (filter_hash) {
5590 orig_hash = &iter->ops->func_hash->filter_hash;
5591 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5592 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5593 } else
5594 orig_hash = &iter->ops->func_hash->notrace_hash;
5595
5596 mutex_lock(&ftrace_lock);
5597 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5598 iter->hash, filter_hash);
5599 mutex_unlock(&ftrace_lock);
5600 } else {
5601 /* For read only, the hash is the ops hash */
5602 iter->hash = NULL;
5603 }
5604
5605 mutex_unlock(&iter->ops->func_hash->regex_lock);
5606 free_ftrace_hash(iter->hash);
5607 if (iter->tr)
5608 trace_array_put(iter->tr);
5609 kfree(iter);
5610
5611 return 0;
5612}
5613
5614static const struct file_operations ftrace_avail_fops = {
5615 .open = ftrace_avail_open,
5616 .read = seq_read,
5617 .llseek = seq_lseek,
5618 .release = seq_release_private,
5619};
5620
5621static const struct file_operations ftrace_enabled_fops = {
5622 .open = ftrace_enabled_open,
5623 .read = seq_read,
5624 .llseek = seq_lseek,
5625 .release = seq_release_private,
5626};
5627
5628static const struct file_operations ftrace_filter_fops = {
5629 .open = ftrace_filter_open,
5630 .read = seq_read,
5631 .write = ftrace_filter_write,
5632 .llseek = tracing_lseek,
5633 .release = ftrace_regex_release,
5634};
5635
5636static const struct file_operations ftrace_notrace_fops = {
5637 .open = ftrace_notrace_open,
5638 .read = seq_read,
5639 .write = ftrace_notrace_write,
5640 .llseek = tracing_lseek,
5641 .release = ftrace_regex_release,
5642};
5643
5644#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5645
5646static DEFINE_MUTEX(graph_lock);
5647
5648struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5649struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5650
5651enum graph_filter_type {
5652 GRAPH_FILTER_NOTRACE = 0,
5653 GRAPH_FILTER_FUNCTION,
5654};
5655
5656#define FTRACE_GRAPH_EMPTY ((void *)1)
5657
5658struct ftrace_graph_data {
5659 struct ftrace_hash *hash;
5660 struct ftrace_func_entry *entry;
5661 int idx; /* for hash table iteration */
5662 enum graph_filter_type type;
5663 struct ftrace_hash *new_hash;
5664 const struct seq_operations *seq_ops;
5665 struct trace_parser parser;
5666};
5667
5668static void *
5669__g_next(struct seq_file *m, loff_t *pos)
5670{
5671 struct ftrace_graph_data *fgd = m->private;
5672 struct ftrace_func_entry *entry = fgd->entry;
5673 struct hlist_head *head;
5674 int i, idx = fgd->idx;
5675
5676 if (*pos >= fgd->hash->count)
5677 return NULL;
5678
5679 if (entry) {
5680 hlist_for_each_entry_continue(entry, hlist) {
5681 fgd->entry = entry;
5682 return entry;
5683 }
5684
5685 idx++;
5686 }
5687
5688 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5689 head = &fgd->hash->buckets[i];
5690 hlist_for_each_entry(entry, head, hlist) {
5691 fgd->entry = entry;
5692 fgd->idx = i;
5693 return entry;
5694 }
5695 }
5696 return NULL;
5697}
5698
5699static void *
5700g_next(struct seq_file *m, void *v, loff_t *pos)
5701{
5702 (*pos)++;
5703 return __g_next(m, pos);
5704}
5705
5706static void *g_start(struct seq_file *m, loff_t *pos)
5707{
5708 struct ftrace_graph_data *fgd = m->private;
5709
5710 mutex_lock(&graph_lock);
5711
5712 if (fgd->type == GRAPH_FILTER_FUNCTION)
5713 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5714 lockdep_is_held(&graph_lock));
5715 else
5716 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5717 lockdep_is_held(&graph_lock));
5718
5719 /* Nothing, tell g_show to print all functions are enabled */
5720 if (ftrace_hash_empty(fgd->hash) && !*pos)
5721 return FTRACE_GRAPH_EMPTY;
5722
5723 fgd->idx = 0;
5724 fgd->entry = NULL;
5725 return __g_next(m, pos);
5726}
5727
5728static void g_stop(struct seq_file *m, void *p)
5729{
5730 mutex_unlock(&graph_lock);
5731}
5732
5733static int g_show(struct seq_file *m, void *v)
5734{
5735 struct ftrace_func_entry *entry = v;
5736
5737 if (!entry)
5738 return 0;
5739
5740 if (entry == FTRACE_GRAPH_EMPTY) {
5741 struct ftrace_graph_data *fgd = m->private;
5742
5743 if (fgd->type == GRAPH_FILTER_FUNCTION)
5744 seq_puts(m, "#### all functions enabled ####\n");
5745 else
5746 seq_puts(m, "#### no functions disabled ####\n");
5747 return 0;
5748 }
5749
5750 seq_printf(m, "%ps\n", (void *)entry->ip);
5751
5752 return 0;
5753}
5754
5755static const struct seq_operations ftrace_graph_seq_ops = {
5756 .start = g_start,
5757 .next = g_next,
5758 .stop = g_stop,
5759 .show = g_show,
5760};
5761
5762static int
5763__ftrace_graph_open(struct inode *inode, struct file *file,
5764 struct ftrace_graph_data *fgd)
5765{
5766 int ret;
5767 struct ftrace_hash *new_hash = NULL;
5768
5769 ret = security_locked_down(LOCKDOWN_TRACEFS);
5770 if (ret)
5771 return ret;
5772
5773 if (file->f_mode & FMODE_WRITE) {
5774 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5775
5776 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5777 return -ENOMEM;
5778
5779 if (file->f_flags & O_TRUNC)
5780 new_hash = alloc_ftrace_hash(size_bits);
5781 else
5782 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5783 fgd->hash);
5784 if (!new_hash) {
5785 ret = -ENOMEM;
5786 goto out;
5787 }
5788 }
5789
5790 if (file->f_mode & FMODE_READ) {
5791 ret = seq_open(file, &ftrace_graph_seq_ops);
5792 if (!ret) {
5793 struct seq_file *m = file->private_data;
5794 m->private = fgd;
5795 } else {
5796 /* Failed */
5797 free_ftrace_hash(new_hash);
5798 new_hash = NULL;
5799 }
5800 } else
5801 file->private_data = fgd;
5802
5803out:
5804 if (ret < 0 && file->f_mode & FMODE_WRITE)
5805 trace_parser_put(&fgd->parser);
5806
5807 fgd->new_hash = new_hash;
5808
5809 /*
5810 * All uses of fgd->hash must be taken with the graph_lock
5811 * held. The graph_lock is going to be released, so force
5812 * fgd->hash to be reinitialized when it is taken again.
5813 */
5814 fgd->hash = NULL;
5815
5816 return ret;
5817}
5818
5819static int
5820ftrace_graph_open(struct inode *inode, struct file *file)
5821{
5822 struct ftrace_graph_data *fgd;
5823 int ret;
5824
5825 if (unlikely(ftrace_disabled))
5826 return -ENODEV;
5827
5828 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5829 if (fgd == NULL)
5830 return -ENOMEM;
5831
5832 mutex_lock(&graph_lock);
5833
5834 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5835 lockdep_is_held(&graph_lock));
5836 fgd->type = GRAPH_FILTER_FUNCTION;
5837 fgd->seq_ops = &ftrace_graph_seq_ops;
5838
5839 ret = __ftrace_graph_open(inode, file, fgd);
5840 if (ret < 0)
5841 kfree(fgd);
5842
5843 mutex_unlock(&graph_lock);
5844 return ret;
5845}
5846
5847static int
5848ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5849{
5850 struct ftrace_graph_data *fgd;
5851 int ret;
5852
5853 if (unlikely(ftrace_disabled))
5854 return -ENODEV;
5855
5856 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5857 if (fgd == NULL)
5858 return -ENOMEM;
5859
5860 mutex_lock(&graph_lock);
5861
5862 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5863 lockdep_is_held(&graph_lock));
5864 fgd->type = GRAPH_FILTER_NOTRACE;
5865 fgd->seq_ops = &ftrace_graph_seq_ops;
5866
5867 ret = __ftrace_graph_open(inode, file, fgd);
5868 if (ret < 0)
5869 kfree(fgd);
5870
5871 mutex_unlock(&graph_lock);
5872 return ret;
5873}
5874
5875static int
5876ftrace_graph_release(struct inode *inode, struct file *file)
5877{
5878 struct ftrace_graph_data *fgd;
5879 struct ftrace_hash *old_hash, *new_hash;
5880 struct trace_parser *parser;
5881 int ret = 0;
5882
5883 if (file->f_mode & FMODE_READ) {
5884 struct seq_file *m = file->private_data;
5885
5886 fgd = m->private;
5887 seq_release(inode, file);
5888 } else {
5889 fgd = file->private_data;
5890 }
5891
5892
5893 if (file->f_mode & FMODE_WRITE) {
5894
5895 parser = &fgd->parser;
5896
5897 if (trace_parser_loaded((parser))) {
5898 ret = ftrace_graph_set_hash(fgd->new_hash,
5899 parser->buffer);
5900 }
5901
5902 trace_parser_put(parser);
5903
5904 new_hash = __ftrace_hash_move(fgd->new_hash);
5905 if (!new_hash) {
5906 ret = -ENOMEM;
5907 goto out;
5908 }
5909
5910 mutex_lock(&graph_lock);
5911
5912 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5913 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5914 lockdep_is_held(&graph_lock));
5915 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5916 } else {
5917 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5918 lockdep_is_held(&graph_lock));
5919 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5920 }
5921
5922 mutex_unlock(&graph_lock);
5923
5924 /*
5925 * We need to do a hard force of sched synchronization.
5926 * This is because we use preempt_disable() to do RCU, but
5927 * the function tracers can be called where RCU is not watching
5928 * (like before user_exit()). We can not rely on the RCU
5929 * infrastructure to do the synchronization, thus we must do it
5930 * ourselves.
5931 */
5932 synchronize_rcu_tasks_rude();
5933
5934 free_ftrace_hash(old_hash);
5935 }
5936
5937 out:
5938 free_ftrace_hash(fgd->new_hash);
5939 kfree(fgd);
5940
5941 return ret;
5942}
5943
5944static int
5945ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5946{
5947 struct ftrace_glob func_g;
5948 struct dyn_ftrace *rec;
5949 struct ftrace_page *pg;
5950 struct ftrace_func_entry *entry;
5951 int fail = 1;
5952 int not;
5953
5954 /* decode regex */
5955 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5956 &func_g.search, ¬);
5957
5958 func_g.len = strlen(func_g.search);
5959
5960 mutex_lock(&ftrace_lock);
5961
5962 if (unlikely(ftrace_disabled)) {
5963 mutex_unlock(&ftrace_lock);
5964 return -ENODEV;
5965 }
5966
5967 do_for_each_ftrace_rec(pg, rec) {
5968
5969 if (rec->flags & FTRACE_FL_DISABLED)
5970 continue;
5971
5972 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5973 entry = ftrace_lookup_ip(hash, rec->ip);
5974
5975 if (!not) {
5976 fail = 0;
5977
5978 if (entry)
5979 continue;
5980 if (add_hash_entry(hash, rec->ip) < 0)
5981 goto out;
5982 } else {
5983 if (entry) {
5984 free_hash_entry(hash, entry);
5985 fail = 0;
5986 }
5987 }
5988 }
5989 } while_for_each_ftrace_rec();
5990out:
5991 mutex_unlock(&ftrace_lock);
5992
5993 if (fail)
5994 return -EINVAL;
5995
5996 return 0;
5997}
5998
5999static ssize_t
6000ftrace_graph_write(struct file *file, const char __user *ubuf,
6001 size_t cnt, loff_t *ppos)
6002{
6003 ssize_t read, ret = 0;
6004 struct ftrace_graph_data *fgd = file->private_data;
6005 struct trace_parser *parser;
6006
6007 if (!cnt)
6008 return 0;
6009
6010 /* Read mode uses seq functions */
6011 if (file->f_mode & FMODE_READ) {
6012 struct seq_file *m = file->private_data;
6013 fgd = m->private;
6014 }
6015
6016 parser = &fgd->parser;
6017
6018 read = trace_get_user(parser, ubuf, cnt, ppos);
6019
6020 if (read >= 0 && trace_parser_loaded(parser) &&
6021 !trace_parser_cont(parser)) {
6022
6023 ret = ftrace_graph_set_hash(fgd->new_hash,
6024 parser->buffer);
6025 trace_parser_clear(parser);
6026 }
6027
6028 if (!ret)
6029 ret = read;
6030
6031 return ret;
6032}
6033
6034static const struct file_operations ftrace_graph_fops = {
6035 .open = ftrace_graph_open,
6036 .read = seq_read,
6037 .write = ftrace_graph_write,
6038 .llseek = tracing_lseek,
6039 .release = ftrace_graph_release,
6040};
6041
6042static const struct file_operations ftrace_graph_notrace_fops = {
6043 .open = ftrace_graph_notrace_open,
6044 .read = seq_read,
6045 .write = ftrace_graph_write,
6046 .llseek = tracing_lseek,
6047 .release = ftrace_graph_release,
6048};
6049#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6050
6051void ftrace_create_filter_files(struct ftrace_ops *ops,
6052 struct dentry *parent)
6053{
6054
6055 trace_create_file("set_ftrace_filter", 0644, parent,
6056 ops, &ftrace_filter_fops);
6057
6058 trace_create_file("set_ftrace_notrace", 0644, parent,
6059 ops, &ftrace_notrace_fops);
6060}
6061
6062/*
6063 * The name "destroy_filter_files" is really a misnomer. Although
6064 * in the future, it may actually delete the files, but this is
6065 * really intended to make sure the ops passed in are disabled
6066 * and that when this function returns, the caller is free to
6067 * free the ops.
6068 *
6069 * The "destroy" name is only to match the "create" name that this
6070 * should be paired with.
6071 */
6072void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6073{
6074 mutex_lock(&ftrace_lock);
6075 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6076 ftrace_shutdown(ops, 0);
6077 ops->flags |= FTRACE_OPS_FL_DELETED;
6078 ftrace_free_filter(ops);
6079 mutex_unlock(&ftrace_lock);
6080}
6081
6082static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6083{
6084
6085 trace_create_file("available_filter_functions", 0444,
6086 d_tracer, NULL, &ftrace_avail_fops);
6087
6088 trace_create_file("enabled_functions", 0444,
6089 d_tracer, NULL, &ftrace_enabled_fops);
6090
6091 ftrace_create_filter_files(&global_ops, d_tracer);
6092
6093#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6094 trace_create_file("set_graph_function", 0644, d_tracer,
6095 NULL,
6096 &ftrace_graph_fops);
6097 trace_create_file("set_graph_notrace", 0644, d_tracer,
6098 NULL,
6099 &ftrace_graph_notrace_fops);
6100#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6101
6102 return 0;
6103}
6104
6105static int ftrace_cmp_ips(const void *a, const void *b)
6106{
6107 const unsigned long *ipa = a;
6108 const unsigned long *ipb = b;
6109
6110 if (*ipa > *ipb)
6111 return 1;
6112 if (*ipa < *ipb)
6113 return -1;
6114 return 0;
6115}
6116
6117static int ftrace_process_locs(struct module *mod,
6118 unsigned long *start,
6119 unsigned long *end)
6120{
6121 struct ftrace_page *start_pg;
6122 struct ftrace_page *pg;
6123 struct dyn_ftrace *rec;
6124 unsigned long count;
6125 unsigned long *p;
6126 unsigned long addr;
6127 unsigned long flags = 0; /* Shut up gcc */
6128 int ret = -ENOMEM;
6129
6130 count = end - start;
6131
6132 if (!count)
6133 return 0;
6134
6135 sort(start, count, sizeof(*start),
6136 ftrace_cmp_ips, NULL);
6137
6138 start_pg = ftrace_allocate_pages(count);
6139 if (!start_pg)
6140 return -ENOMEM;
6141
6142 mutex_lock(&ftrace_lock);
6143
6144 /*
6145 * Core and each module needs their own pages, as
6146 * modules will free them when they are removed.
6147 * Force a new page to be allocated for modules.
6148 */
6149 if (!mod) {
6150 WARN_ON(ftrace_pages || ftrace_pages_start);
6151 /* First initialization */
6152 ftrace_pages = ftrace_pages_start = start_pg;
6153 } else {
6154 if (!ftrace_pages)
6155 goto out;
6156
6157 if (WARN_ON(ftrace_pages->next)) {
6158 /* Hmm, we have free pages? */
6159 while (ftrace_pages->next)
6160 ftrace_pages = ftrace_pages->next;
6161 }
6162
6163 ftrace_pages->next = start_pg;
6164 }
6165
6166 p = start;
6167 pg = start_pg;
6168 while (p < end) {
6169 addr = ftrace_call_adjust(*p++);
6170 /*
6171 * Some architecture linkers will pad between
6172 * the different mcount_loc sections of different
6173 * object files to satisfy alignments.
6174 * Skip any NULL pointers.
6175 */
6176 if (!addr)
6177 continue;
6178
6179 if (pg->index == pg->size) {
6180 /* We should have allocated enough */
6181 if (WARN_ON(!pg->next))
6182 break;
6183 pg = pg->next;
6184 }
6185
6186 rec = &pg->records[pg->index++];
6187 rec->ip = addr;
6188 }
6189
6190 /* We should have used all pages */
6191 WARN_ON(pg->next);
6192
6193 /* Assign the last page to ftrace_pages */
6194 ftrace_pages = pg;
6195
6196 /*
6197 * We only need to disable interrupts on start up
6198 * because we are modifying code that an interrupt
6199 * may execute, and the modification is not atomic.
6200 * But for modules, nothing runs the code we modify
6201 * until we are finished with it, and there's no
6202 * reason to cause large interrupt latencies while we do it.
6203 */
6204 if (!mod)
6205 local_irq_save(flags);
6206 ftrace_update_code(mod, start_pg);
6207 if (!mod)
6208 local_irq_restore(flags);
6209 ret = 0;
6210 out:
6211 mutex_unlock(&ftrace_lock);
6212
6213 return ret;
6214}
6215
6216struct ftrace_mod_func {
6217 struct list_head list;
6218 char *name;
6219 unsigned long ip;
6220 unsigned int size;
6221};
6222
6223struct ftrace_mod_map {
6224 struct rcu_head rcu;
6225 struct list_head list;
6226 struct module *mod;
6227 unsigned long start_addr;
6228 unsigned long end_addr;
6229 struct list_head funcs;
6230 unsigned int num_funcs;
6231};
6232
6233static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6234 unsigned long *value, char *type,
6235 char *name, char *module_name,
6236 int *exported)
6237{
6238 struct ftrace_ops *op;
6239
6240 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6241 if (!op->trampoline || symnum--)
6242 continue;
6243 *value = op->trampoline;
6244 *type = 't';
6245 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6246 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6247 *exported = 0;
6248 return 0;
6249 }
6250
6251 return -ERANGE;
6252}
6253
6254#ifdef CONFIG_MODULES
6255
6256#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6257
6258static LIST_HEAD(ftrace_mod_maps);
6259
6260static int referenced_filters(struct dyn_ftrace *rec)
6261{
6262 struct ftrace_ops *ops;
6263 int cnt = 0;
6264
6265 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6266 if (ops_references_rec(ops, rec)) {
6267 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6268 continue;
6269 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6270 continue;
6271 cnt++;
6272 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6273 rec->flags |= FTRACE_FL_REGS;
6274 if (cnt == 1 && ops->trampoline)
6275 rec->flags |= FTRACE_FL_TRAMP;
6276 else
6277 rec->flags &= ~FTRACE_FL_TRAMP;
6278 }
6279 }
6280
6281 return cnt;
6282}
6283
6284static void
6285clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6286{
6287 struct ftrace_func_entry *entry;
6288 struct dyn_ftrace *rec;
6289 int i;
6290
6291 if (ftrace_hash_empty(hash))
6292 return;
6293
6294 for (i = 0; i < pg->index; i++) {
6295 rec = &pg->records[i];
6296 entry = __ftrace_lookup_ip(hash, rec->ip);
6297 /*
6298 * Do not allow this rec to match again.
6299 * Yeah, it may waste some memory, but will be removed
6300 * if/when the hash is modified again.
6301 */
6302 if (entry)
6303 entry->ip = 0;
6304 }
6305}
6306
6307/* Clear any records from hashs */
6308static void clear_mod_from_hashes(struct ftrace_page *pg)
6309{
6310 struct trace_array *tr;
6311
6312 mutex_lock(&trace_types_lock);
6313 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6314 if (!tr->ops || !tr->ops->func_hash)
6315 continue;
6316 mutex_lock(&tr->ops->func_hash->regex_lock);
6317 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6318 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6319 mutex_unlock(&tr->ops->func_hash->regex_lock);
6320 }
6321 mutex_unlock(&trace_types_lock);
6322}
6323
6324static void ftrace_free_mod_map(struct rcu_head *rcu)
6325{
6326 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6327 struct ftrace_mod_func *mod_func;
6328 struct ftrace_mod_func *n;
6329
6330 /* All the contents of mod_map are now not visible to readers */
6331 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6332 kfree(mod_func->name);
6333 list_del(&mod_func->list);
6334 kfree(mod_func);
6335 }
6336
6337 kfree(mod_map);
6338}
6339
6340void ftrace_release_mod(struct module *mod)
6341{
6342 struct ftrace_mod_map *mod_map;
6343 struct ftrace_mod_map *n;
6344 struct dyn_ftrace *rec;
6345 struct ftrace_page **last_pg;
6346 struct ftrace_page *tmp_page = NULL;
6347 struct ftrace_page *pg;
6348 int order;
6349
6350 mutex_lock(&ftrace_lock);
6351
6352 if (ftrace_disabled)
6353 goto out_unlock;
6354
6355 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6356 if (mod_map->mod == mod) {
6357 list_del_rcu(&mod_map->list);
6358 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6359 break;
6360 }
6361 }
6362
6363 /*
6364 * Each module has its own ftrace_pages, remove
6365 * them from the list.
6366 */
6367 last_pg = &ftrace_pages_start;
6368 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6369 rec = &pg->records[0];
6370 if (within_module_core(rec->ip, mod) ||
6371 within_module_init(rec->ip, mod)) {
6372 /*
6373 * As core pages are first, the first
6374 * page should never be a module page.
6375 */
6376 if (WARN_ON(pg == ftrace_pages_start))
6377 goto out_unlock;
6378
6379 /* Check if we are deleting the last page */
6380 if (pg == ftrace_pages)
6381 ftrace_pages = next_to_ftrace_page(last_pg);
6382
6383 ftrace_update_tot_cnt -= pg->index;
6384 *last_pg = pg->next;
6385
6386 pg->next = tmp_page;
6387 tmp_page = pg;
6388 } else
6389 last_pg = &pg->next;
6390 }
6391 out_unlock:
6392 mutex_unlock(&ftrace_lock);
6393
6394 for (pg = tmp_page; pg; pg = tmp_page) {
6395
6396 /* Needs to be called outside of ftrace_lock */
6397 clear_mod_from_hashes(pg);
6398
6399 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6400 free_pages((unsigned long)pg->records, order);
6401 tmp_page = pg->next;
6402 kfree(pg);
6403 ftrace_number_of_pages -= 1 << order;
6404 ftrace_number_of_groups--;
6405 }
6406}
6407
6408void ftrace_module_enable(struct module *mod)
6409{
6410 struct dyn_ftrace *rec;
6411 struct ftrace_page *pg;
6412
6413 mutex_lock(&ftrace_lock);
6414
6415 if (ftrace_disabled)
6416 goto out_unlock;
6417
6418 /*
6419 * If the tracing is enabled, go ahead and enable the record.
6420 *
6421 * The reason not to enable the record immediately is the
6422 * inherent check of ftrace_make_nop/ftrace_make_call for
6423 * correct previous instructions. Making first the NOP
6424 * conversion puts the module to the correct state, thus
6425 * passing the ftrace_make_call check.
6426 *
6427 * We also delay this to after the module code already set the
6428 * text to read-only, as we now need to set it back to read-write
6429 * so that we can modify the text.
6430 */
6431 if (ftrace_start_up)
6432 ftrace_arch_code_modify_prepare();
6433
6434 do_for_each_ftrace_rec(pg, rec) {
6435 int cnt;
6436 /*
6437 * do_for_each_ftrace_rec() is a double loop.
6438 * module text shares the pg. If a record is
6439 * not part of this module, then skip this pg,
6440 * which the "break" will do.
6441 */
6442 if (!within_module_core(rec->ip, mod) &&
6443 !within_module_init(rec->ip, mod))
6444 break;
6445
6446 cnt = 0;
6447
6448 /*
6449 * When adding a module, we need to check if tracers are
6450 * currently enabled and if they are, and can trace this record,
6451 * we need to enable the module functions as well as update the
6452 * reference counts for those function records.
6453 */
6454 if (ftrace_start_up)
6455 cnt += referenced_filters(rec);
6456
6457 rec->flags &= ~FTRACE_FL_DISABLED;
6458 rec->flags += cnt;
6459
6460 if (ftrace_start_up && cnt) {
6461 int failed = __ftrace_replace_code(rec, 1);
6462 if (failed) {
6463 ftrace_bug(failed, rec);
6464 goto out_loop;
6465 }
6466 }
6467
6468 } while_for_each_ftrace_rec();
6469
6470 out_loop:
6471 if (ftrace_start_up)
6472 ftrace_arch_code_modify_post_process();
6473
6474 out_unlock:
6475 mutex_unlock(&ftrace_lock);
6476
6477 process_cached_mods(mod->name);
6478}
6479
6480void ftrace_module_init(struct module *mod)
6481{
6482 if (ftrace_disabled || !mod->num_ftrace_callsites)
6483 return;
6484
6485 ftrace_process_locs(mod, mod->ftrace_callsites,
6486 mod->ftrace_callsites + mod->num_ftrace_callsites);
6487}
6488
6489static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6490 struct dyn_ftrace *rec)
6491{
6492 struct ftrace_mod_func *mod_func;
6493 unsigned long symsize;
6494 unsigned long offset;
6495 char str[KSYM_SYMBOL_LEN];
6496 char *modname;
6497 const char *ret;
6498
6499 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6500 if (!ret)
6501 return;
6502
6503 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6504 if (!mod_func)
6505 return;
6506
6507 mod_func->name = kstrdup(str, GFP_KERNEL);
6508 if (!mod_func->name) {
6509 kfree(mod_func);
6510 return;
6511 }
6512
6513 mod_func->ip = rec->ip - offset;
6514 mod_func->size = symsize;
6515
6516 mod_map->num_funcs++;
6517
6518 list_add_rcu(&mod_func->list, &mod_map->funcs);
6519}
6520
6521static struct ftrace_mod_map *
6522allocate_ftrace_mod_map(struct module *mod,
6523 unsigned long start, unsigned long end)
6524{
6525 struct ftrace_mod_map *mod_map;
6526
6527 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6528 if (!mod_map)
6529 return NULL;
6530
6531 mod_map->mod = mod;
6532 mod_map->start_addr = start;
6533 mod_map->end_addr = end;
6534 mod_map->num_funcs = 0;
6535
6536 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6537
6538 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6539
6540 return mod_map;
6541}
6542
6543static const char *
6544ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6545 unsigned long addr, unsigned long *size,
6546 unsigned long *off, char *sym)
6547{
6548 struct ftrace_mod_func *found_func = NULL;
6549 struct ftrace_mod_func *mod_func;
6550
6551 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6552 if (addr >= mod_func->ip &&
6553 addr < mod_func->ip + mod_func->size) {
6554 found_func = mod_func;
6555 break;
6556 }
6557 }
6558
6559 if (found_func) {
6560 if (size)
6561 *size = found_func->size;
6562 if (off)
6563 *off = addr - found_func->ip;
6564 if (sym)
6565 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6566
6567 return found_func->name;
6568 }
6569
6570 return NULL;
6571}
6572
6573const char *
6574ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6575 unsigned long *off, char **modname, char *sym)
6576{
6577 struct ftrace_mod_map *mod_map;
6578 const char *ret = NULL;
6579
6580 /* mod_map is freed via call_rcu() */
6581 preempt_disable();
6582 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6583 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6584 if (ret) {
6585 if (modname)
6586 *modname = mod_map->mod->name;
6587 break;
6588 }
6589 }
6590 preempt_enable();
6591
6592 return ret;
6593}
6594
6595int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6596 char *type, char *name,
6597 char *module_name, int *exported)
6598{
6599 struct ftrace_mod_map *mod_map;
6600 struct ftrace_mod_func *mod_func;
6601 int ret;
6602
6603 preempt_disable();
6604 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6605
6606 if (symnum >= mod_map->num_funcs) {
6607 symnum -= mod_map->num_funcs;
6608 continue;
6609 }
6610
6611 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6612 if (symnum > 1) {
6613 symnum--;
6614 continue;
6615 }
6616
6617 *value = mod_func->ip;
6618 *type = 'T';
6619 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6620 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6621 *exported = 1;
6622 preempt_enable();
6623 return 0;
6624 }
6625 WARN_ON(1);
6626 break;
6627 }
6628 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6629 module_name, exported);
6630 preempt_enable();
6631 return ret;
6632}
6633
6634#else
6635static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6636 struct dyn_ftrace *rec) { }
6637static inline struct ftrace_mod_map *
6638allocate_ftrace_mod_map(struct module *mod,
6639 unsigned long start, unsigned long end)
6640{
6641 return NULL;
6642}
6643int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6644 char *type, char *name, char *module_name,
6645 int *exported)
6646{
6647 int ret;
6648
6649 preempt_disable();
6650 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6651 module_name, exported);
6652 preempt_enable();
6653 return ret;
6654}
6655#endif /* CONFIG_MODULES */
6656
6657struct ftrace_init_func {
6658 struct list_head list;
6659 unsigned long ip;
6660};
6661
6662/* Clear any init ips from hashes */
6663static void
6664clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6665{
6666 struct ftrace_func_entry *entry;
6667
6668 entry = ftrace_lookup_ip(hash, func->ip);
6669 /*
6670 * Do not allow this rec to match again.
6671 * Yeah, it may waste some memory, but will be removed
6672 * if/when the hash is modified again.
6673 */
6674 if (entry)
6675 entry->ip = 0;
6676}
6677
6678static void
6679clear_func_from_hashes(struct ftrace_init_func *func)
6680{
6681 struct trace_array *tr;
6682
6683 mutex_lock(&trace_types_lock);
6684 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6685 if (!tr->ops || !tr->ops->func_hash)
6686 continue;
6687 mutex_lock(&tr->ops->func_hash->regex_lock);
6688 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6689 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6690 mutex_unlock(&tr->ops->func_hash->regex_lock);
6691 }
6692 mutex_unlock(&trace_types_lock);
6693}
6694
6695static void add_to_clear_hash_list(struct list_head *clear_list,
6696 struct dyn_ftrace *rec)
6697{
6698 struct ftrace_init_func *func;
6699
6700 func = kmalloc(sizeof(*func), GFP_KERNEL);
6701 if (!func) {
6702 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6703 return;
6704 }
6705
6706 func->ip = rec->ip;
6707 list_add(&func->list, clear_list);
6708}
6709
6710void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6711{
6712 unsigned long start = (unsigned long)(start_ptr);
6713 unsigned long end = (unsigned long)(end_ptr);
6714 struct ftrace_page **last_pg = &ftrace_pages_start;
6715 struct ftrace_page *pg;
6716 struct dyn_ftrace *rec;
6717 struct dyn_ftrace key;
6718 struct ftrace_mod_map *mod_map = NULL;
6719 struct ftrace_init_func *func, *func_next;
6720 struct list_head clear_hash;
6721 int order;
6722
6723 INIT_LIST_HEAD(&clear_hash);
6724
6725 key.ip = start;
6726 key.flags = end; /* overload flags, as it is unsigned long */
6727
6728 mutex_lock(&ftrace_lock);
6729
6730 /*
6731 * If we are freeing module init memory, then check if
6732 * any tracer is active. If so, we need to save a mapping of
6733 * the module functions being freed with the address.
6734 */
6735 if (mod && ftrace_ops_list != &ftrace_list_end)
6736 mod_map = allocate_ftrace_mod_map(mod, start, end);
6737
6738 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6739 if (end < pg->records[0].ip ||
6740 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6741 continue;
6742 again:
6743 rec = bsearch(&key, pg->records, pg->index,
6744 sizeof(struct dyn_ftrace),
6745 ftrace_cmp_recs);
6746 if (!rec)
6747 continue;
6748
6749 /* rec will be cleared from hashes after ftrace_lock unlock */
6750 add_to_clear_hash_list(&clear_hash, rec);
6751
6752 if (mod_map)
6753 save_ftrace_mod_rec(mod_map, rec);
6754
6755 pg->index--;
6756 ftrace_update_tot_cnt--;
6757 if (!pg->index) {
6758 *last_pg = pg->next;
6759 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6760 free_pages((unsigned long)pg->records, order);
6761 ftrace_number_of_pages -= 1 << order;
6762 ftrace_number_of_groups--;
6763 kfree(pg);
6764 pg = container_of(last_pg, struct ftrace_page, next);
6765 if (!(*last_pg))
6766 ftrace_pages = pg;
6767 continue;
6768 }
6769 memmove(rec, rec + 1,
6770 (pg->index - (rec - pg->records)) * sizeof(*rec));
6771 /* More than one function may be in this block */
6772 goto again;
6773 }
6774 mutex_unlock(&ftrace_lock);
6775
6776 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6777 clear_func_from_hashes(func);
6778 kfree(func);
6779 }
6780}
6781
6782void __init ftrace_free_init_mem(void)
6783{
6784 void *start = (void *)(&__init_begin);
6785 void *end = (void *)(&__init_end);
6786
6787 ftrace_free_mem(NULL, start, end);
6788}
6789
6790void __init ftrace_init(void)
6791{
6792 extern unsigned long __start_mcount_loc[];
6793 extern unsigned long __stop_mcount_loc[];
6794 unsigned long count, flags;
6795 int ret;
6796
6797 local_irq_save(flags);
6798 ret = ftrace_dyn_arch_init();
6799 local_irq_restore(flags);
6800 if (ret)
6801 goto failed;
6802
6803 count = __stop_mcount_loc - __start_mcount_loc;
6804 if (!count) {
6805 pr_info("ftrace: No functions to be traced?\n");
6806 goto failed;
6807 }
6808
6809 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6810 count, count / ENTRIES_PER_PAGE + 1);
6811
6812 last_ftrace_enabled = ftrace_enabled = 1;
6813
6814 ret = ftrace_process_locs(NULL,
6815 __start_mcount_loc,
6816 __stop_mcount_loc);
6817
6818 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6819 ftrace_number_of_pages, ftrace_number_of_groups);
6820
6821 set_ftrace_early_filters();
6822
6823 return;
6824 failed:
6825 ftrace_disabled = 1;
6826}
6827
6828/* Do nothing if arch does not support this */
6829void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6830{
6831}
6832
6833static void ftrace_update_trampoline(struct ftrace_ops *ops)
6834{
6835 unsigned long trampoline = ops->trampoline;
6836
6837 arch_ftrace_update_trampoline(ops);
6838 if (ops->trampoline && ops->trampoline != trampoline &&
6839 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6840 /* Add to kallsyms before the perf events */
6841 ftrace_add_trampoline_to_kallsyms(ops);
6842 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6843 ops->trampoline, ops->trampoline_size, false,
6844 FTRACE_TRAMPOLINE_SYM);
6845 /*
6846 * Record the perf text poke event after the ksymbol register
6847 * event.
6848 */
6849 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6850 (void *)ops->trampoline,
6851 ops->trampoline_size);
6852 }
6853}
6854
6855void ftrace_init_trace_array(struct trace_array *tr)
6856{
6857 INIT_LIST_HEAD(&tr->func_probes);
6858 INIT_LIST_HEAD(&tr->mod_trace);
6859 INIT_LIST_HEAD(&tr->mod_notrace);
6860}
6861#else
6862
6863struct ftrace_ops global_ops = {
6864 .func = ftrace_stub,
6865 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6866 FTRACE_OPS_FL_INITIALIZED |
6867 FTRACE_OPS_FL_PID,
6868};
6869
6870static int __init ftrace_nodyn_init(void)
6871{
6872 ftrace_enabled = 1;
6873 return 0;
6874}
6875core_initcall(ftrace_nodyn_init);
6876
6877static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6878static inline void ftrace_startup_enable(int command) { }
6879static inline void ftrace_startup_all(int command) { }
6880
6881# define ftrace_startup_sysctl() do { } while (0)
6882# define ftrace_shutdown_sysctl() do { } while (0)
6883
6884static void ftrace_update_trampoline(struct ftrace_ops *ops)
6885{
6886}
6887
6888#endif /* CONFIG_DYNAMIC_FTRACE */
6889
6890__init void ftrace_init_global_array_ops(struct trace_array *tr)
6891{
6892 tr->ops = &global_ops;
6893 tr->ops->private = tr;
6894 ftrace_init_trace_array(tr);
6895}
6896
6897void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6898{
6899 /* If we filter on pids, update to use the pid function */
6900 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6901 if (WARN_ON(tr->ops->func != ftrace_stub))
6902 printk("ftrace ops had %pS for function\n",
6903 tr->ops->func);
6904 }
6905 tr->ops->func = func;
6906 tr->ops->private = tr;
6907}
6908
6909void ftrace_reset_array_ops(struct trace_array *tr)
6910{
6911 tr->ops->func = ftrace_stub;
6912}
6913
6914static nokprobe_inline void
6915__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6916 struct ftrace_ops *ignored, struct pt_regs *regs)
6917{
6918 struct ftrace_ops *op;
6919 int bit;
6920
6921 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6922 if (bit < 0)
6923 return;
6924
6925 /*
6926 * Some of the ops may be dynamically allocated,
6927 * they must be freed after a synchronize_rcu().
6928 */
6929 preempt_disable_notrace();
6930
6931 do_for_each_ftrace_op(op, ftrace_ops_list) {
6932 /* Stub functions don't need to be called nor tested */
6933 if (op->flags & FTRACE_OPS_FL_STUB)
6934 continue;
6935 /*
6936 * Check the following for each ops before calling their func:
6937 * if RCU flag is set, then rcu_is_watching() must be true
6938 * if PER_CPU is set, then ftrace_function_local_disable()
6939 * must be false
6940 * Otherwise test if the ip matches the ops filter
6941 *
6942 * If any of the above fails then the op->func() is not executed.
6943 */
6944 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6945 ftrace_ops_test(op, ip, regs)) {
6946 if (FTRACE_WARN_ON(!op->func)) {
6947 pr_warn("op=%p %pS\n", op, op);
6948 goto out;
6949 }
6950 op->func(ip, parent_ip, op, regs);
6951 }
6952 } while_for_each_ftrace_op(op);
6953out:
6954 preempt_enable_notrace();
6955 trace_clear_recursion(bit);
6956}
6957
6958/*
6959 * Some archs only support passing ip and parent_ip. Even though
6960 * the list function ignores the op parameter, we do not want any
6961 * C side effects, where a function is called without the caller
6962 * sending a third parameter.
6963 * Archs are to support both the regs and ftrace_ops at the same time.
6964 * If they support ftrace_ops, it is assumed they support regs.
6965 * If call backs want to use regs, they must either check for regs
6966 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6967 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6968 * An architecture can pass partial regs with ftrace_ops and still
6969 * set the ARCH_SUPPORTS_FTRACE_OPS.
6970 */
6971#if ARCH_SUPPORTS_FTRACE_OPS
6972static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6973 struct ftrace_ops *op, struct pt_regs *regs)
6974{
6975 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6976}
6977NOKPROBE_SYMBOL(ftrace_ops_list_func);
6978#else
6979static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6980{
6981 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6982}
6983NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6984#endif
6985
6986/*
6987 * If there's only one function registered but it does not support
6988 * recursion, needs RCU protection and/or requires per cpu handling, then
6989 * this function will be called by the mcount trampoline.
6990 */
6991static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6992 struct ftrace_ops *op, struct pt_regs *regs)
6993{
6994 int bit;
6995
6996 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6997 if (bit < 0)
6998 return;
6999
7000 preempt_disable_notrace();
7001
7002 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7003 op->func(ip, parent_ip, op, regs);
7004
7005 preempt_enable_notrace();
7006 trace_clear_recursion(bit);
7007}
7008NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7009
7010/**
7011 * ftrace_ops_get_func - get the function a trampoline should call
7012 * @ops: the ops to get the function for
7013 *
7014 * Normally the mcount trampoline will call the ops->func, but there
7015 * are times that it should not. For example, if the ops does not
7016 * have its own recursion protection, then it should call the
7017 * ftrace_ops_assist_func() instead.
7018 *
7019 * Returns the function that the trampoline should call for @ops.
7020 */
7021ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7022{
7023 /*
7024 * If the function does not handle recursion, needs to be RCU safe,
7025 * or does per cpu logic, then we need to call the assist handler.
7026 */
7027 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
7028 ops->flags & FTRACE_OPS_FL_RCU)
7029 return ftrace_ops_assist_func;
7030
7031 return ops->func;
7032}
7033
7034static void
7035ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7036 struct task_struct *prev, struct task_struct *next)
7037{
7038 struct trace_array *tr = data;
7039 struct trace_pid_list *pid_list;
7040 struct trace_pid_list *no_pid_list;
7041
7042 pid_list = rcu_dereference_sched(tr->function_pids);
7043 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7044
7045 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7046 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7047 FTRACE_PID_IGNORE);
7048 else
7049 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7050 next->pid);
7051}
7052
7053static void
7054ftrace_pid_follow_sched_process_fork(void *data,
7055 struct task_struct *self,
7056 struct task_struct *task)
7057{
7058 struct trace_pid_list *pid_list;
7059 struct trace_array *tr = data;
7060
7061 pid_list = rcu_dereference_sched(tr->function_pids);
7062 trace_filter_add_remove_task(pid_list, self, task);
7063
7064 pid_list = rcu_dereference_sched(tr->function_no_pids);
7065 trace_filter_add_remove_task(pid_list, self, task);
7066}
7067
7068static void
7069ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7070{
7071 struct trace_pid_list *pid_list;
7072 struct trace_array *tr = data;
7073
7074 pid_list = rcu_dereference_sched(tr->function_pids);
7075 trace_filter_add_remove_task(pid_list, NULL, task);
7076
7077 pid_list = rcu_dereference_sched(tr->function_no_pids);
7078 trace_filter_add_remove_task(pid_list, NULL, task);
7079}
7080
7081void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7082{
7083 if (enable) {
7084 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7085 tr);
7086 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7087 tr);
7088 } else {
7089 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7090 tr);
7091 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7092 tr);
7093 }
7094}
7095
7096static void clear_ftrace_pids(struct trace_array *tr, int type)
7097{
7098 struct trace_pid_list *pid_list;
7099 struct trace_pid_list *no_pid_list;
7100 int cpu;
7101
7102 pid_list = rcu_dereference_protected(tr->function_pids,
7103 lockdep_is_held(&ftrace_lock));
7104 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7105 lockdep_is_held(&ftrace_lock));
7106
7107 /* Make sure there's something to do */
7108 if (!pid_type_enabled(type, pid_list, no_pid_list))
7109 return;
7110
7111 /* See if the pids still need to be checked after this */
7112 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7113 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7114 for_each_possible_cpu(cpu)
7115 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7116 }
7117
7118 if (type & TRACE_PIDS)
7119 rcu_assign_pointer(tr->function_pids, NULL);
7120
7121 if (type & TRACE_NO_PIDS)
7122 rcu_assign_pointer(tr->function_no_pids, NULL);
7123
7124 /* Wait till all users are no longer using pid filtering */
7125 synchronize_rcu();
7126
7127 if ((type & TRACE_PIDS) && pid_list)
7128 trace_free_pid_list(pid_list);
7129
7130 if ((type & TRACE_NO_PIDS) && no_pid_list)
7131 trace_free_pid_list(no_pid_list);
7132}
7133
7134void ftrace_clear_pids(struct trace_array *tr)
7135{
7136 mutex_lock(&ftrace_lock);
7137
7138 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7139
7140 mutex_unlock(&ftrace_lock);
7141}
7142
7143static void ftrace_pid_reset(struct trace_array *tr, int type)
7144{
7145 mutex_lock(&ftrace_lock);
7146 clear_ftrace_pids(tr, type);
7147
7148 ftrace_update_pid_func();
7149 ftrace_startup_all(0);
7150
7151 mutex_unlock(&ftrace_lock);
7152}
7153
7154/* Greater than any max PID */
7155#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7156
7157static void *fpid_start(struct seq_file *m, loff_t *pos)
7158 __acquires(RCU)
7159{
7160 struct trace_pid_list *pid_list;
7161 struct trace_array *tr = m->private;
7162
7163 mutex_lock(&ftrace_lock);
7164 rcu_read_lock_sched();
7165
7166 pid_list = rcu_dereference_sched(tr->function_pids);
7167
7168 if (!pid_list)
7169 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7170
7171 return trace_pid_start(pid_list, pos);
7172}
7173
7174static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7175{
7176 struct trace_array *tr = m->private;
7177 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7178
7179 if (v == FTRACE_NO_PIDS) {
7180 (*pos)++;
7181 return NULL;
7182 }
7183 return trace_pid_next(pid_list, v, pos);
7184}
7185
7186static void fpid_stop(struct seq_file *m, void *p)
7187 __releases(RCU)
7188{
7189 rcu_read_unlock_sched();
7190 mutex_unlock(&ftrace_lock);
7191}
7192
7193static int fpid_show(struct seq_file *m, void *v)
7194{
7195 if (v == FTRACE_NO_PIDS) {
7196 seq_puts(m, "no pid\n");
7197 return 0;
7198 }
7199
7200 return trace_pid_show(m, v);
7201}
7202
7203static const struct seq_operations ftrace_pid_sops = {
7204 .start = fpid_start,
7205 .next = fpid_next,
7206 .stop = fpid_stop,
7207 .show = fpid_show,
7208};
7209
7210static void *fnpid_start(struct seq_file *m, loff_t *pos)
7211 __acquires(RCU)
7212{
7213 struct trace_pid_list *pid_list;
7214 struct trace_array *tr = m->private;
7215
7216 mutex_lock(&ftrace_lock);
7217 rcu_read_lock_sched();
7218
7219 pid_list = rcu_dereference_sched(tr->function_no_pids);
7220
7221 if (!pid_list)
7222 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7223
7224 return trace_pid_start(pid_list, pos);
7225}
7226
7227static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7228{
7229 struct trace_array *tr = m->private;
7230 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7231
7232 if (v == FTRACE_NO_PIDS) {
7233 (*pos)++;
7234 return NULL;
7235 }
7236 return trace_pid_next(pid_list, v, pos);
7237}
7238
7239static const struct seq_operations ftrace_no_pid_sops = {
7240 .start = fnpid_start,
7241 .next = fnpid_next,
7242 .stop = fpid_stop,
7243 .show = fpid_show,
7244};
7245
7246static int pid_open(struct inode *inode, struct file *file, int type)
7247{
7248 const struct seq_operations *seq_ops;
7249 struct trace_array *tr = inode->i_private;
7250 struct seq_file *m;
7251 int ret = 0;
7252
7253 ret = tracing_check_open_get_tr(tr);
7254 if (ret)
7255 return ret;
7256
7257 if ((file->f_mode & FMODE_WRITE) &&
7258 (file->f_flags & O_TRUNC))
7259 ftrace_pid_reset(tr, type);
7260
7261 switch (type) {
7262 case TRACE_PIDS:
7263 seq_ops = &ftrace_pid_sops;
7264 break;
7265 case TRACE_NO_PIDS:
7266 seq_ops = &ftrace_no_pid_sops;
7267 break;
7268 default:
7269 trace_array_put(tr);
7270 WARN_ON_ONCE(1);
7271 return -EINVAL;
7272 }
7273
7274 ret = seq_open(file, seq_ops);
7275 if (ret < 0) {
7276 trace_array_put(tr);
7277 } else {
7278 m = file->private_data;
7279 /* copy tr over to seq ops */
7280 m->private = tr;
7281 }
7282
7283 return ret;
7284}
7285
7286static int
7287ftrace_pid_open(struct inode *inode, struct file *file)
7288{
7289 return pid_open(inode, file, TRACE_PIDS);
7290}
7291
7292static int
7293ftrace_no_pid_open(struct inode *inode, struct file *file)
7294{
7295 return pid_open(inode, file, TRACE_NO_PIDS);
7296}
7297
7298static void ignore_task_cpu(void *data)
7299{
7300 struct trace_array *tr = data;
7301 struct trace_pid_list *pid_list;
7302 struct trace_pid_list *no_pid_list;
7303
7304 /*
7305 * This function is called by on_each_cpu() while the
7306 * event_mutex is held.
7307 */
7308 pid_list = rcu_dereference_protected(tr->function_pids,
7309 mutex_is_locked(&ftrace_lock));
7310 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7311 mutex_is_locked(&ftrace_lock));
7312
7313 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7314 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7315 FTRACE_PID_IGNORE);
7316 else
7317 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7318 current->pid);
7319}
7320
7321static ssize_t
7322pid_write(struct file *filp, const char __user *ubuf,
7323 size_t cnt, loff_t *ppos, int type)
7324{
7325 struct seq_file *m = filp->private_data;
7326 struct trace_array *tr = m->private;
7327 struct trace_pid_list *filtered_pids;
7328 struct trace_pid_list *other_pids;
7329 struct trace_pid_list *pid_list;
7330 ssize_t ret;
7331
7332 if (!cnt)
7333 return 0;
7334
7335 mutex_lock(&ftrace_lock);
7336
7337 switch (type) {
7338 case TRACE_PIDS:
7339 filtered_pids = rcu_dereference_protected(tr->function_pids,
7340 lockdep_is_held(&ftrace_lock));
7341 other_pids = rcu_dereference_protected(tr->function_no_pids,
7342 lockdep_is_held(&ftrace_lock));
7343 break;
7344 case TRACE_NO_PIDS:
7345 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7346 lockdep_is_held(&ftrace_lock));
7347 other_pids = rcu_dereference_protected(tr->function_pids,
7348 lockdep_is_held(&ftrace_lock));
7349 break;
7350 default:
7351 ret = -EINVAL;
7352 WARN_ON_ONCE(1);
7353 goto out;
7354 }
7355
7356 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7357 if (ret < 0)
7358 goto out;
7359
7360 switch (type) {
7361 case TRACE_PIDS:
7362 rcu_assign_pointer(tr->function_pids, pid_list);
7363 break;
7364 case TRACE_NO_PIDS:
7365 rcu_assign_pointer(tr->function_no_pids, pid_list);
7366 break;
7367 }
7368
7369
7370 if (filtered_pids) {
7371 synchronize_rcu();
7372 trace_free_pid_list(filtered_pids);
7373 } else if (pid_list && !other_pids) {
7374 /* Register a probe to set whether to ignore the tracing of a task */
7375 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7376 }
7377
7378 /*
7379 * Ignoring of pids is done at task switch. But we have to
7380 * check for those tasks that are currently running.
7381 * Always do this in case a pid was appended or removed.
7382 */
7383 on_each_cpu(ignore_task_cpu, tr, 1);
7384
7385 ftrace_update_pid_func();
7386 ftrace_startup_all(0);
7387 out:
7388 mutex_unlock(&ftrace_lock);
7389
7390 if (ret > 0)
7391 *ppos += ret;
7392
7393 return ret;
7394}
7395
7396static ssize_t
7397ftrace_pid_write(struct file *filp, const char __user *ubuf,
7398 size_t cnt, loff_t *ppos)
7399{
7400 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7401}
7402
7403static ssize_t
7404ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7405 size_t cnt, loff_t *ppos)
7406{
7407 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7408}
7409
7410static int
7411ftrace_pid_release(struct inode *inode, struct file *file)
7412{
7413 struct trace_array *tr = inode->i_private;
7414
7415 trace_array_put(tr);
7416
7417 return seq_release(inode, file);
7418}
7419
7420static const struct file_operations ftrace_pid_fops = {
7421 .open = ftrace_pid_open,
7422 .write = ftrace_pid_write,
7423 .read = seq_read,
7424 .llseek = tracing_lseek,
7425 .release = ftrace_pid_release,
7426};
7427
7428static const struct file_operations ftrace_no_pid_fops = {
7429 .open = ftrace_no_pid_open,
7430 .write = ftrace_no_pid_write,
7431 .read = seq_read,
7432 .llseek = tracing_lseek,
7433 .release = ftrace_pid_release,
7434};
7435
7436void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7437{
7438 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7439 tr, &ftrace_pid_fops);
7440 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7441 tr, &ftrace_no_pid_fops);
7442}
7443
7444void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7445 struct dentry *d_tracer)
7446{
7447 /* Only the top level directory has the dyn_tracefs and profile */
7448 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7449
7450 ftrace_init_dyn_tracefs(d_tracer);
7451 ftrace_profile_tracefs(d_tracer);
7452}
7453
7454/**
7455 * ftrace_kill - kill ftrace
7456 *
7457 * This function should be used by panic code. It stops ftrace
7458 * but in a not so nice way. If you need to simply kill ftrace
7459 * from a non-atomic section, use ftrace_kill.
7460 */
7461void ftrace_kill(void)
7462{
7463 ftrace_disabled = 1;
7464 ftrace_enabled = 0;
7465 ftrace_trace_function = ftrace_stub;
7466}
7467
7468/**
7469 * Test if ftrace is dead or not.
7470 */
7471int ftrace_is_dead(void)
7472{
7473 return ftrace_disabled;
7474}
7475
7476/**
7477 * register_ftrace_function - register a function for profiling
7478 * @ops - ops structure that holds the function for profiling.
7479 *
7480 * Register a function to be called by all functions in the
7481 * kernel.
7482 *
7483 * Note: @ops->func and all the functions it calls must be labeled
7484 * with "notrace", otherwise it will go into a
7485 * recursive loop.
7486 */
7487int register_ftrace_function(struct ftrace_ops *ops)
7488{
7489 int ret = -1;
7490
7491 ftrace_ops_init(ops);
7492
7493 mutex_lock(&ftrace_lock);
7494
7495 ret = ftrace_startup(ops, 0);
7496
7497 mutex_unlock(&ftrace_lock);
7498
7499 return ret;
7500}
7501EXPORT_SYMBOL_GPL(register_ftrace_function);
7502
7503/**
7504 * unregister_ftrace_function - unregister a function for profiling.
7505 * @ops - ops structure that holds the function to unregister
7506 *
7507 * Unregister a function that was added to be called by ftrace profiling.
7508 */
7509int unregister_ftrace_function(struct ftrace_ops *ops)
7510{
7511 int ret;
7512
7513 mutex_lock(&ftrace_lock);
7514 ret = ftrace_shutdown(ops, 0);
7515 mutex_unlock(&ftrace_lock);
7516
7517 return ret;
7518}
7519EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7520
7521static bool is_permanent_ops_registered(void)
7522{
7523 struct ftrace_ops *op;
7524
7525 do_for_each_ftrace_op(op, ftrace_ops_list) {
7526 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7527 return true;
7528 } while_for_each_ftrace_op(op);
7529
7530 return false;
7531}
7532
7533int
7534ftrace_enable_sysctl(struct ctl_table *table, int write,
7535 void *buffer, size_t *lenp, loff_t *ppos)
7536{
7537 int ret = -ENODEV;
7538
7539 mutex_lock(&ftrace_lock);
7540
7541 if (unlikely(ftrace_disabled))
7542 goto out;
7543
7544 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7545
7546 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7547 goto out;
7548
7549 if (ftrace_enabled) {
7550
7551 /* we are starting ftrace again */
7552 if (rcu_dereference_protected(ftrace_ops_list,
7553 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7554 update_ftrace_function();
7555
7556 ftrace_startup_sysctl();
7557
7558 } else {
7559 if (is_permanent_ops_registered()) {
7560 ftrace_enabled = true;
7561 ret = -EBUSY;
7562 goto out;
7563 }
7564
7565 /* stopping ftrace calls (just send to ftrace_stub) */
7566 ftrace_trace_function = ftrace_stub;
7567
7568 ftrace_shutdown_sysctl();
7569 }
7570
7571 last_ftrace_enabled = !!ftrace_enabled;
7572 out:
7573 mutex_unlock(&ftrace_lock);
7574 return ret;
7575}