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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/* Flags that do not get reset */
49#define FTRACE_NOCLEAR_FLAGS (FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
50 FTRACE_FL_MODIFIED)
51
52#define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
53
54#define FTRACE_WARN_ON(cond) \
55 ({ \
56 int ___r = cond; \
57 if (WARN_ON(___r)) \
58 ftrace_kill(); \
59 ___r; \
60 })
61
62#define FTRACE_WARN_ON_ONCE(cond) \
63 ({ \
64 int ___r = cond; \
65 if (WARN_ON_ONCE(___r)) \
66 ftrace_kill(); \
67 ___r; \
68 })
69
70/* hash bits for specific function selection */
71#define FTRACE_HASH_DEFAULT_BITS 10
72#define FTRACE_HASH_MAX_BITS 12
73
74#ifdef CONFIG_DYNAMIC_FTRACE
75#define INIT_OPS_HASH(opsname) \
76 .func_hash = &opsname.local_hash, \
77 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), \
78 .subop_list = LIST_HEAD_INIT(opsname.subop_list),
79#else
80#define INIT_OPS_HASH(opsname)
81#endif
82
83enum {
84 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
85 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
86};
87
88struct ftrace_ops ftrace_list_end __read_mostly = {
89 .func = ftrace_stub,
90 .flags = FTRACE_OPS_FL_STUB,
91 INIT_OPS_HASH(ftrace_list_end)
92};
93
94/* ftrace_enabled is a method to turn ftrace on or off */
95int ftrace_enabled __read_mostly;
96static int __maybe_unused last_ftrace_enabled;
97
98/* Current function tracing op */
99struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
100/* What to set function_trace_op to */
101static struct ftrace_ops *set_function_trace_op;
102
103bool ftrace_pids_enabled(struct ftrace_ops *ops)
104{
105 struct trace_array *tr;
106
107 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
108 return false;
109
110 tr = ops->private;
111
112 return tr->function_pids != NULL || tr->function_no_pids != NULL;
113}
114
115static void ftrace_update_trampoline(struct ftrace_ops *ops);
116
117/*
118 * ftrace_disabled is set when an anomaly is discovered.
119 * ftrace_disabled is much stronger than ftrace_enabled.
120 */
121static int ftrace_disabled __read_mostly;
122
123DEFINE_MUTEX(ftrace_lock);
124
125struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = (struct ftrace_ops __rcu *)&ftrace_list_end;
126ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
127struct ftrace_ops global_ops;
128
129/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
130void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
131 struct ftrace_ops *op, struct ftrace_regs *fregs);
132
133#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
134/*
135 * Stub used to invoke the list ops without requiring a separate trampoline.
136 */
137const struct ftrace_ops ftrace_list_ops = {
138 .func = ftrace_ops_list_func,
139 .flags = FTRACE_OPS_FL_STUB,
140};
141
142static void ftrace_ops_nop_func(unsigned long ip, unsigned long parent_ip,
143 struct ftrace_ops *op,
144 struct ftrace_regs *fregs)
145{
146 /* do nothing */
147}
148
149/*
150 * Stub used when a call site is disabled. May be called transiently by threads
151 * which have made it into ftrace_caller but haven't yet recovered the ops at
152 * the point the call site is disabled.
153 */
154const struct ftrace_ops ftrace_nop_ops = {
155 .func = ftrace_ops_nop_func,
156 .flags = FTRACE_OPS_FL_STUB,
157};
158#endif
159
160static inline void ftrace_ops_init(struct ftrace_ops *ops)
161{
162#ifdef CONFIG_DYNAMIC_FTRACE
163 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
164 mutex_init(&ops->local_hash.regex_lock);
165 INIT_LIST_HEAD(&ops->subop_list);
166 ops->func_hash = &ops->local_hash;
167 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
168 }
169#endif
170}
171
172/* Call this function for when a callback filters on set_ftrace_pid */
173static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
174 struct ftrace_ops *op, struct ftrace_regs *fregs)
175{
176 struct trace_array *tr = op->private;
177 int pid;
178
179 if (tr) {
180 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
181 if (pid == FTRACE_PID_IGNORE)
182 return;
183 if (pid != FTRACE_PID_TRACE &&
184 pid != current->pid)
185 return;
186 }
187
188 op->saved_func(ip, parent_ip, op, fregs);
189}
190
191static void ftrace_sync_ipi(void *data)
192{
193 /* Probably not needed, but do it anyway */
194 smp_rmb();
195}
196
197static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
198{
199 /*
200 * If this is a dynamic or RCU ops, or we force list func,
201 * then it needs to call the list anyway.
202 */
203 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
204 FTRACE_FORCE_LIST_FUNC)
205 return ftrace_ops_list_func;
206
207 return ftrace_ops_get_func(ops);
208}
209
210static void update_ftrace_function(void)
211{
212 ftrace_func_t func;
213
214 /*
215 * Prepare the ftrace_ops that the arch callback will use.
216 * If there's only one ftrace_ops registered, the ftrace_ops_list
217 * will point to the ops we want.
218 */
219 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
220 lockdep_is_held(&ftrace_lock));
221
222 /* If there's no ftrace_ops registered, just call the stub function */
223 if (set_function_trace_op == &ftrace_list_end) {
224 func = ftrace_stub;
225
226 /*
227 * If we are at the end of the list and this ops is
228 * recursion safe and not dynamic and the arch supports passing ops,
229 * then have the mcount trampoline call the function directly.
230 */
231 } else if (rcu_dereference_protected(ftrace_ops_list->next,
232 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
233 func = ftrace_ops_get_list_func(ftrace_ops_list);
234
235 } else {
236 /* Just use the default ftrace_ops */
237 set_function_trace_op = &ftrace_list_end;
238 func = ftrace_ops_list_func;
239 }
240
241 /* If there's no change, then do nothing more here */
242 if (ftrace_trace_function == func)
243 return;
244
245 /*
246 * If we are using the list function, it doesn't care
247 * about the function_trace_ops.
248 */
249 if (func == ftrace_ops_list_func) {
250 ftrace_trace_function = func;
251 /*
252 * Don't even bother setting function_trace_ops,
253 * it would be racy to do so anyway.
254 */
255 return;
256 }
257
258#ifndef CONFIG_DYNAMIC_FTRACE
259 /*
260 * For static tracing, we need to be a bit more careful.
261 * The function change takes affect immediately. Thus,
262 * we need to coordinate the setting of the function_trace_ops
263 * with the setting of the ftrace_trace_function.
264 *
265 * Set the function to the list ops, which will call the
266 * function we want, albeit indirectly, but it handles the
267 * ftrace_ops and doesn't depend on function_trace_op.
268 */
269 ftrace_trace_function = ftrace_ops_list_func;
270 /*
271 * Make sure all CPUs see this. Yes this is slow, but static
272 * tracing is slow and nasty to have enabled.
273 */
274 synchronize_rcu_tasks_rude();
275 /* Now all cpus are using the list ops. */
276 function_trace_op = set_function_trace_op;
277 /* Make sure the function_trace_op is visible on all CPUs */
278 smp_wmb();
279 /* Nasty way to force a rmb on all cpus */
280 smp_call_function(ftrace_sync_ipi, NULL, 1);
281 /* OK, we are all set to update the ftrace_trace_function now! */
282#endif /* !CONFIG_DYNAMIC_FTRACE */
283
284 ftrace_trace_function = func;
285}
286
287static void add_ftrace_ops(struct ftrace_ops __rcu **list,
288 struct ftrace_ops *ops)
289{
290 rcu_assign_pointer(ops->next, *list);
291
292 /*
293 * We are entering ops into the list but another
294 * CPU might be walking that list. We need to make sure
295 * the ops->next pointer is valid before another CPU sees
296 * the ops pointer included into the list.
297 */
298 rcu_assign_pointer(*list, ops);
299}
300
301static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
302 struct ftrace_ops *ops)
303{
304 struct ftrace_ops **p;
305
306 /*
307 * If we are removing the last function, then simply point
308 * to the ftrace_stub.
309 */
310 if (rcu_dereference_protected(*list,
311 lockdep_is_held(&ftrace_lock)) == ops &&
312 rcu_dereference_protected(ops->next,
313 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
314 rcu_assign_pointer(*list, &ftrace_list_end);
315 return 0;
316 }
317
318 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
319 if (*p == ops)
320 break;
321
322 if (*p != ops)
323 return -1;
324
325 *p = (*p)->next;
326 return 0;
327}
328
329static void ftrace_update_trampoline(struct ftrace_ops *ops);
330
331int __register_ftrace_function(struct ftrace_ops *ops)
332{
333 if (ops->flags & FTRACE_OPS_FL_DELETED)
334 return -EINVAL;
335
336 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
337 return -EBUSY;
338
339#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
340 /*
341 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
342 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
343 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
344 */
345 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
346 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
347 return -EINVAL;
348
349 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
350 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
351#endif
352 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
353 return -EBUSY;
354
355 if (!is_kernel_core_data((unsigned long)ops))
356 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
357
358 add_ftrace_ops(&ftrace_ops_list, ops);
359
360 /* Always save the function, and reset at unregistering */
361 ops->saved_func = ops->func;
362
363 if (ftrace_pids_enabled(ops))
364 ops->func = ftrace_pid_func;
365
366 ftrace_update_trampoline(ops);
367
368 if (ftrace_enabled)
369 update_ftrace_function();
370
371 return 0;
372}
373
374int __unregister_ftrace_function(struct ftrace_ops *ops)
375{
376 int ret;
377
378 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
379 return -EBUSY;
380
381 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
382
383 if (ret < 0)
384 return ret;
385
386 if (ftrace_enabled)
387 update_ftrace_function();
388
389 ops->func = ops->saved_func;
390
391 return 0;
392}
393
394static void ftrace_update_pid_func(void)
395{
396 struct ftrace_ops *op;
397
398 /* Only do something if we are tracing something */
399 if (ftrace_trace_function == ftrace_stub)
400 return;
401
402 do_for_each_ftrace_op(op, ftrace_ops_list) {
403 if (op->flags & FTRACE_OPS_FL_PID) {
404 op->func = ftrace_pids_enabled(op) ?
405 ftrace_pid_func : op->saved_func;
406 ftrace_update_trampoline(op);
407 }
408 } while_for_each_ftrace_op(op);
409
410 fgraph_update_pid_func();
411
412 update_ftrace_function();
413}
414
415#ifdef CONFIG_FUNCTION_PROFILER
416struct ftrace_profile {
417 struct hlist_node node;
418 unsigned long ip;
419 unsigned long counter;
420#ifdef CONFIG_FUNCTION_GRAPH_TRACER
421 unsigned long long time;
422 unsigned long long time_squared;
423#endif
424};
425
426struct ftrace_profile_page {
427 struct ftrace_profile_page *next;
428 unsigned long index;
429 struct ftrace_profile records[];
430};
431
432struct ftrace_profile_stat {
433 atomic_t disabled;
434 struct hlist_head *hash;
435 struct ftrace_profile_page *pages;
436 struct ftrace_profile_page *start;
437 struct tracer_stat stat;
438};
439
440#define PROFILE_RECORDS_SIZE \
441 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
442
443#define PROFILES_PER_PAGE \
444 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
445
446static int ftrace_profile_enabled __read_mostly;
447
448/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
449static DEFINE_MUTEX(ftrace_profile_lock);
450
451static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
452
453#define FTRACE_PROFILE_HASH_BITS 10
454#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
455
456static void *
457function_stat_next(void *v, int idx)
458{
459 struct ftrace_profile *rec = v;
460 struct ftrace_profile_page *pg;
461
462 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
463
464 again:
465 if (idx != 0)
466 rec++;
467
468 if ((void *)rec >= (void *)&pg->records[pg->index]) {
469 pg = pg->next;
470 if (!pg)
471 return NULL;
472 rec = &pg->records[0];
473 if (!rec->counter)
474 goto again;
475 }
476
477 return rec;
478}
479
480static void *function_stat_start(struct tracer_stat *trace)
481{
482 struct ftrace_profile_stat *stat =
483 container_of(trace, struct ftrace_profile_stat, stat);
484
485 if (!stat || !stat->start)
486 return NULL;
487
488 return function_stat_next(&stat->start->records[0], 0);
489}
490
491#ifdef CONFIG_FUNCTION_GRAPH_TRACER
492/* function graph compares on total time */
493static int function_stat_cmp(const void *p1, const void *p2)
494{
495 const struct ftrace_profile *a = p1;
496 const struct ftrace_profile *b = p2;
497
498 if (a->time < b->time)
499 return -1;
500 if (a->time > b->time)
501 return 1;
502 else
503 return 0;
504}
505#else
506/* not function graph compares against hits */
507static int function_stat_cmp(const void *p1, const void *p2)
508{
509 const struct ftrace_profile *a = p1;
510 const struct ftrace_profile *b = p2;
511
512 if (a->counter < b->counter)
513 return -1;
514 if (a->counter > b->counter)
515 return 1;
516 else
517 return 0;
518}
519#endif
520
521static int function_stat_headers(struct seq_file *m)
522{
523#ifdef CONFIG_FUNCTION_GRAPH_TRACER
524 seq_puts(m, " Function "
525 "Hit Time Avg s^2\n"
526 " -------- "
527 "--- ---- --- ---\n");
528#else
529 seq_puts(m, " Function Hit\n"
530 " -------- ---\n");
531#endif
532 return 0;
533}
534
535static int function_stat_show(struct seq_file *m, void *v)
536{
537 struct ftrace_profile *rec = v;
538 char str[KSYM_SYMBOL_LEN];
539 int ret = 0;
540#ifdef CONFIG_FUNCTION_GRAPH_TRACER
541 static struct trace_seq s;
542 unsigned long long avg;
543 unsigned long long stddev;
544 unsigned long long stddev_denom;
545#endif
546 mutex_lock(&ftrace_profile_lock);
547
548 /* we raced with function_profile_reset() */
549 if (unlikely(rec->counter == 0)) {
550 ret = -EBUSY;
551 goto out;
552 }
553
554#ifdef CONFIG_FUNCTION_GRAPH_TRACER
555 avg = div64_ul(rec->time, rec->counter);
556 if (tracing_thresh && (avg < tracing_thresh))
557 goto out;
558#endif
559
560 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
561 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
562
563#ifdef CONFIG_FUNCTION_GRAPH_TRACER
564 seq_puts(m, " ");
565
566 /*
567 * Variance formula:
568 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
569 * Maybe Welford's method is better here?
570 * Divide only by 1000 for ns^2 -> us^2 conversion.
571 * trace_print_graph_duration will divide by 1000 again.
572 */
573 stddev = 0;
574 stddev_denom = rec->counter * (rec->counter - 1) * 1000;
575 if (stddev_denom) {
576 stddev = rec->counter * rec->time_squared -
577 rec->time * rec->time;
578 stddev = div64_ul(stddev, stddev_denom);
579 }
580
581 trace_seq_init(&s);
582 trace_print_graph_duration(rec->time, &s);
583 trace_seq_puts(&s, " ");
584 trace_print_graph_duration(avg, &s);
585 trace_seq_puts(&s, " ");
586 trace_print_graph_duration(stddev, &s);
587 trace_print_seq(m, &s);
588#endif
589 seq_putc(m, '\n');
590out:
591 mutex_unlock(&ftrace_profile_lock);
592
593 return ret;
594}
595
596static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
597{
598 struct ftrace_profile_page *pg;
599
600 pg = stat->pages = stat->start;
601
602 while (pg) {
603 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
604 pg->index = 0;
605 pg = pg->next;
606 }
607
608 memset(stat->hash, 0,
609 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
610}
611
612static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
613{
614 struct ftrace_profile_page *pg;
615 int functions;
616 int pages;
617 int i;
618
619 /* If we already allocated, do nothing */
620 if (stat->pages)
621 return 0;
622
623 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
624 if (!stat->pages)
625 return -ENOMEM;
626
627#ifdef CONFIG_DYNAMIC_FTRACE
628 functions = ftrace_update_tot_cnt;
629#else
630 /*
631 * We do not know the number of functions that exist because
632 * dynamic tracing is what counts them. With past experience
633 * we have around 20K functions. That should be more than enough.
634 * It is highly unlikely we will execute every function in
635 * the kernel.
636 */
637 functions = 20000;
638#endif
639
640 pg = stat->start = stat->pages;
641
642 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
643
644 for (i = 1; i < pages; i++) {
645 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
646 if (!pg->next)
647 goto out_free;
648 pg = pg->next;
649 }
650
651 return 0;
652
653 out_free:
654 pg = stat->start;
655 while (pg) {
656 unsigned long tmp = (unsigned long)pg;
657
658 pg = pg->next;
659 free_page(tmp);
660 }
661
662 stat->pages = NULL;
663 stat->start = NULL;
664
665 return -ENOMEM;
666}
667
668static int ftrace_profile_init_cpu(int cpu)
669{
670 struct ftrace_profile_stat *stat;
671 int size;
672
673 stat = &per_cpu(ftrace_profile_stats, cpu);
674
675 if (stat->hash) {
676 /* If the profile is already created, simply reset it */
677 ftrace_profile_reset(stat);
678 return 0;
679 }
680
681 /*
682 * We are profiling all functions, but usually only a few thousand
683 * functions are hit. We'll make a hash of 1024 items.
684 */
685 size = FTRACE_PROFILE_HASH_SIZE;
686
687 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
688
689 if (!stat->hash)
690 return -ENOMEM;
691
692 /* Preallocate the function profiling pages */
693 if (ftrace_profile_pages_init(stat) < 0) {
694 kfree(stat->hash);
695 stat->hash = NULL;
696 return -ENOMEM;
697 }
698
699 return 0;
700}
701
702static int ftrace_profile_init(void)
703{
704 int cpu;
705 int ret = 0;
706
707 for_each_possible_cpu(cpu) {
708 ret = ftrace_profile_init_cpu(cpu);
709 if (ret)
710 break;
711 }
712
713 return ret;
714}
715
716/* interrupts must be disabled */
717static struct ftrace_profile *
718ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
719{
720 struct ftrace_profile *rec;
721 struct hlist_head *hhd;
722 unsigned long key;
723
724 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
725 hhd = &stat->hash[key];
726
727 if (hlist_empty(hhd))
728 return NULL;
729
730 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
731 if (rec->ip == ip)
732 return rec;
733 }
734
735 return NULL;
736}
737
738static void ftrace_add_profile(struct ftrace_profile_stat *stat,
739 struct ftrace_profile *rec)
740{
741 unsigned long key;
742
743 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
744 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
745}
746
747/*
748 * The memory is already allocated, this simply finds a new record to use.
749 */
750static struct ftrace_profile *
751ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
752{
753 struct ftrace_profile *rec = NULL;
754
755 /* prevent recursion (from NMIs) */
756 if (atomic_inc_return(&stat->disabled) != 1)
757 goto out;
758
759 /*
760 * Try to find the function again since an NMI
761 * could have added it
762 */
763 rec = ftrace_find_profiled_func(stat, ip);
764 if (rec)
765 goto out;
766
767 if (stat->pages->index == PROFILES_PER_PAGE) {
768 if (!stat->pages->next)
769 goto out;
770 stat->pages = stat->pages->next;
771 }
772
773 rec = &stat->pages->records[stat->pages->index++];
774 rec->ip = ip;
775 ftrace_add_profile(stat, rec);
776
777 out:
778 atomic_dec(&stat->disabled);
779
780 return rec;
781}
782
783static void
784function_profile_call(unsigned long ip, unsigned long parent_ip,
785 struct ftrace_ops *ops, struct ftrace_regs *fregs)
786{
787 struct ftrace_profile_stat *stat;
788 struct ftrace_profile *rec;
789 unsigned long flags;
790
791 if (!ftrace_profile_enabled)
792 return;
793
794 local_irq_save(flags);
795
796 stat = this_cpu_ptr(&ftrace_profile_stats);
797 if (!stat->hash || !ftrace_profile_enabled)
798 goto out;
799
800 rec = ftrace_find_profiled_func(stat, ip);
801 if (!rec) {
802 rec = ftrace_profile_alloc(stat, ip);
803 if (!rec)
804 goto out;
805 }
806
807 rec->counter++;
808 out:
809 local_irq_restore(flags);
810}
811
812#ifdef CONFIG_FUNCTION_GRAPH_TRACER
813static bool fgraph_graph_time = true;
814
815void ftrace_graph_graph_time_control(bool enable)
816{
817 fgraph_graph_time = enable;
818}
819
820struct profile_fgraph_data {
821 unsigned long long calltime;
822 unsigned long long subtime;
823 unsigned long long sleeptime;
824};
825
826static int profile_graph_entry(struct ftrace_graph_ent *trace,
827 struct fgraph_ops *gops)
828{
829 struct profile_fgraph_data *profile_data;
830
831 function_profile_call(trace->func, 0, NULL, NULL);
832
833 /* If function graph is shutting down, ret_stack can be NULL */
834 if (!current->ret_stack)
835 return 0;
836
837 profile_data = fgraph_reserve_data(gops->idx, sizeof(*profile_data));
838 if (!profile_data)
839 return 0;
840
841 profile_data->subtime = 0;
842 profile_data->sleeptime = current->ftrace_sleeptime;
843 profile_data->calltime = trace_clock_local();
844
845 return 1;
846}
847
848static void profile_graph_return(struct ftrace_graph_ret *trace,
849 struct fgraph_ops *gops)
850{
851 struct profile_fgraph_data *profile_data;
852 struct ftrace_profile_stat *stat;
853 unsigned long long calltime;
854 unsigned long long rettime = trace_clock_local();
855 struct ftrace_profile *rec;
856 unsigned long flags;
857 int size;
858
859 local_irq_save(flags);
860 stat = this_cpu_ptr(&ftrace_profile_stats);
861 if (!stat->hash || !ftrace_profile_enabled)
862 goto out;
863
864 profile_data = fgraph_retrieve_data(gops->idx, &size);
865
866 /* If the calltime was zero'd ignore it */
867 if (!profile_data || !profile_data->calltime)
868 goto out;
869
870 calltime = rettime - profile_data->calltime;
871
872 if (!fgraph_sleep_time) {
873 if (current->ftrace_sleeptime)
874 calltime -= current->ftrace_sleeptime - profile_data->sleeptime;
875 }
876
877 if (!fgraph_graph_time) {
878 struct profile_fgraph_data *parent_data;
879
880 /* Append this call time to the parent time to subtract */
881 parent_data = fgraph_retrieve_parent_data(gops->idx, &size, 1);
882 if (parent_data)
883 parent_data->subtime += calltime;
884
885 if (profile_data->subtime && profile_data->subtime < calltime)
886 calltime -= profile_data->subtime;
887 else
888 calltime = 0;
889 }
890
891 rec = ftrace_find_profiled_func(stat, trace->func);
892 if (rec) {
893 rec->time += calltime;
894 rec->time_squared += calltime * calltime;
895 }
896
897 out:
898 local_irq_restore(flags);
899}
900
901static struct fgraph_ops fprofiler_ops = {
902 .entryfunc = &profile_graph_entry,
903 .retfunc = &profile_graph_return,
904};
905
906static int register_ftrace_profiler(void)
907{
908 ftrace_ops_set_global_filter(&fprofiler_ops.ops);
909 return register_ftrace_graph(&fprofiler_ops);
910}
911
912static void unregister_ftrace_profiler(void)
913{
914 unregister_ftrace_graph(&fprofiler_ops);
915}
916#else
917static struct ftrace_ops ftrace_profile_ops __read_mostly = {
918 .func = function_profile_call,
919};
920
921static int register_ftrace_profiler(void)
922{
923 ftrace_ops_set_global_filter(&ftrace_profile_ops);
924 return register_ftrace_function(&ftrace_profile_ops);
925}
926
927static void unregister_ftrace_profiler(void)
928{
929 unregister_ftrace_function(&ftrace_profile_ops);
930}
931#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
932
933static ssize_t
934ftrace_profile_write(struct file *filp, const char __user *ubuf,
935 size_t cnt, loff_t *ppos)
936{
937 unsigned long val;
938 int ret;
939
940 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
941 if (ret)
942 return ret;
943
944 val = !!val;
945
946 mutex_lock(&ftrace_profile_lock);
947 if (ftrace_profile_enabled ^ val) {
948 if (val) {
949 ret = ftrace_profile_init();
950 if (ret < 0) {
951 cnt = ret;
952 goto out;
953 }
954
955 ret = register_ftrace_profiler();
956 if (ret < 0) {
957 cnt = ret;
958 goto out;
959 }
960 ftrace_profile_enabled = 1;
961 } else {
962 ftrace_profile_enabled = 0;
963 /*
964 * unregister_ftrace_profiler calls stop_machine
965 * so this acts like an synchronize_rcu.
966 */
967 unregister_ftrace_profiler();
968 }
969 }
970 out:
971 mutex_unlock(&ftrace_profile_lock);
972
973 *ppos += cnt;
974
975 return cnt;
976}
977
978static ssize_t
979ftrace_profile_read(struct file *filp, char __user *ubuf,
980 size_t cnt, loff_t *ppos)
981{
982 char buf[64]; /* big enough to hold a number */
983 int r;
984
985 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
986 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
987}
988
989static const struct file_operations ftrace_profile_fops = {
990 .open = tracing_open_generic,
991 .read = ftrace_profile_read,
992 .write = ftrace_profile_write,
993 .llseek = default_llseek,
994};
995
996/* used to initialize the real stat files */
997static struct tracer_stat function_stats __initdata = {
998 .name = "functions",
999 .stat_start = function_stat_start,
1000 .stat_next = function_stat_next,
1001 .stat_cmp = function_stat_cmp,
1002 .stat_headers = function_stat_headers,
1003 .stat_show = function_stat_show
1004};
1005
1006static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1007{
1008 struct ftrace_profile_stat *stat;
1009 char *name;
1010 int ret;
1011 int cpu;
1012
1013 for_each_possible_cpu(cpu) {
1014 stat = &per_cpu(ftrace_profile_stats, cpu);
1015
1016 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1017 if (!name) {
1018 /*
1019 * The files created are permanent, if something happens
1020 * we still do not free memory.
1021 */
1022 WARN(1,
1023 "Could not allocate stat file for cpu %d\n",
1024 cpu);
1025 return;
1026 }
1027 stat->stat = function_stats;
1028 stat->stat.name = name;
1029 ret = register_stat_tracer(&stat->stat);
1030 if (ret) {
1031 WARN(1,
1032 "Could not register function stat for cpu %d\n",
1033 cpu);
1034 kfree(name);
1035 return;
1036 }
1037 }
1038
1039 trace_create_file("function_profile_enabled",
1040 TRACE_MODE_WRITE, d_tracer, NULL,
1041 &ftrace_profile_fops);
1042}
1043
1044#else /* CONFIG_FUNCTION_PROFILER */
1045static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1046{
1047}
1048#endif /* CONFIG_FUNCTION_PROFILER */
1049
1050#ifdef CONFIG_DYNAMIC_FTRACE
1051
1052static struct ftrace_ops *removed_ops;
1053
1054/*
1055 * Set when doing a global update, like enabling all recs or disabling them.
1056 * It is not set when just updating a single ftrace_ops.
1057 */
1058static bool update_all_ops;
1059
1060#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1061# error Dynamic ftrace depends on MCOUNT_RECORD
1062#endif
1063
1064struct ftrace_func_probe {
1065 struct ftrace_probe_ops *probe_ops;
1066 struct ftrace_ops ops;
1067 struct trace_array *tr;
1068 struct list_head list;
1069 void *data;
1070 int ref;
1071};
1072
1073/*
1074 * We make these constant because no one should touch them,
1075 * but they are used as the default "empty hash", to avoid allocating
1076 * it all the time. These are in a read only section such that if
1077 * anyone does try to modify it, it will cause an exception.
1078 */
1079static const struct hlist_head empty_buckets[1];
1080static const struct ftrace_hash empty_hash = {
1081 .buckets = (struct hlist_head *)empty_buckets,
1082};
1083#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1084
1085struct ftrace_ops global_ops = {
1086 .func = ftrace_stub,
1087 .local_hash.notrace_hash = EMPTY_HASH,
1088 .local_hash.filter_hash = EMPTY_HASH,
1089 INIT_OPS_HASH(global_ops)
1090 .flags = FTRACE_OPS_FL_INITIALIZED |
1091 FTRACE_OPS_FL_PID,
1092};
1093
1094/*
1095 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1096 */
1097struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1098{
1099 struct ftrace_ops *op = NULL;
1100
1101 /*
1102 * Some of the ops may be dynamically allocated,
1103 * they are freed after a synchronize_rcu().
1104 */
1105 preempt_disable_notrace();
1106
1107 do_for_each_ftrace_op(op, ftrace_ops_list) {
1108 /*
1109 * This is to check for dynamically allocated trampolines.
1110 * Trampolines that are in kernel text will have
1111 * core_kernel_text() return true.
1112 */
1113 if (op->trampoline && op->trampoline_size)
1114 if (addr >= op->trampoline &&
1115 addr < op->trampoline + op->trampoline_size) {
1116 preempt_enable_notrace();
1117 return op;
1118 }
1119 } while_for_each_ftrace_op(op);
1120 preempt_enable_notrace();
1121
1122 return NULL;
1123}
1124
1125/*
1126 * This is used by __kernel_text_address() to return true if the
1127 * address is on a dynamically allocated trampoline that would
1128 * not return true for either core_kernel_text() or
1129 * is_module_text_address().
1130 */
1131bool is_ftrace_trampoline(unsigned long addr)
1132{
1133 return ftrace_ops_trampoline(addr) != NULL;
1134}
1135
1136struct ftrace_page {
1137 struct ftrace_page *next;
1138 struct dyn_ftrace *records;
1139 int index;
1140 int order;
1141};
1142
1143#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1144#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1145
1146static struct ftrace_page *ftrace_pages_start;
1147static struct ftrace_page *ftrace_pages;
1148
1149static __always_inline unsigned long
1150ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1151{
1152 if (hash->size_bits > 0)
1153 return hash_long(ip, hash->size_bits);
1154
1155 return 0;
1156}
1157
1158/* Only use this function if ftrace_hash_empty() has already been tested */
1159static __always_inline struct ftrace_func_entry *
1160__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1161{
1162 unsigned long key;
1163 struct ftrace_func_entry *entry;
1164 struct hlist_head *hhd;
1165
1166 key = ftrace_hash_key(hash, ip);
1167 hhd = &hash->buckets[key];
1168
1169 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1170 if (entry->ip == ip)
1171 return entry;
1172 }
1173 return NULL;
1174}
1175
1176/**
1177 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1178 * @hash: The hash to look at
1179 * @ip: The instruction pointer to test
1180 *
1181 * Search a given @hash to see if a given instruction pointer (@ip)
1182 * exists in it.
1183 *
1184 * Returns: the entry that holds the @ip if found. NULL otherwise.
1185 */
1186struct ftrace_func_entry *
1187ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1188{
1189 if (ftrace_hash_empty(hash))
1190 return NULL;
1191
1192 return __ftrace_lookup_ip(hash, ip);
1193}
1194
1195static void __add_hash_entry(struct ftrace_hash *hash,
1196 struct ftrace_func_entry *entry)
1197{
1198 struct hlist_head *hhd;
1199 unsigned long key;
1200
1201 key = ftrace_hash_key(hash, entry->ip);
1202 hhd = &hash->buckets[key];
1203 hlist_add_head(&entry->hlist, hhd);
1204 hash->count++;
1205}
1206
1207static struct ftrace_func_entry *
1208add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1209{
1210 struct ftrace_func_entry *entry;
1211
1212 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1213 if (!entry)
1214 return NULL;
1215
1216 entry->ip = ip;
1217 __add_hash_entry(hash, entry);
1218
1219 return entry;
1220}
1221
1222static void
1223free_hash_entry(struct ftrace_hash *hash,
1224 struct ftrace_func_entry *entry)
1225{
1226 hlist_del(&entry->hlist);
1227 kfree(entry);
1228 hash->count--;
1229}
1230
1231static void
1232remove_hash_entry(struct ftrace_hash *hash,
1233 struct ftrace_func_entry *entry)
1234{
1235 hlist_del_rcu(&entry->hlist);
1236 hash->count--;
1237}
1238
1239static void ftrace_hash_clear(struct ftrace_hash *hash)
1240{
1241 struct hlist_head *hhd;
1242 struct hlist_node *tn;
1243 struct ftrace_func_entry *entry;
1244 int size = 1 << hash->size_bits;
1245 int i;
1246
1247 if (!hash->count)
1248 return;
1249
1250 for (i = 0; i < size; i++) {
1251 hhd = &hash->buckets[i];
1252 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1253 free_hash_entry(hash, entry);
1254 }
1255 FTRACE_WARN_ON(hash->count);
1256}
1257
1258static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1259{
1260 list_del(&ftrace_mod->list);
1261 kfree(ftrace_mod->module);
1262 kfree(ftrace_mod->func);
1263 kfree(ftrace_mod);
1264}
1265
1266static void clear_ftrace_mod_list(struct list_head *head)
1267{
1268 struct ftrace_mod_load *p, *n;
1269
1270 /* stack tracer isn't supported yet */
1271 if (!head)
1272 return;
1273
1274 mutex_lock(&ftrace_lock);
1275 list_for_each_entry_safe(p, n, head, list)
1276 free_ftrace_mod(p);
1277 mutex_unlock(&ftrace_lock);
1278}
1279
1280static void free_ftrace_hash(struct ftrace_hash *hash)
1281{
1282 if (!hash || hash == EMPTY_HASH)
1283 return;
1284 ftrace_hash_clear(hash);
1285 kfree(hash->buckets);
1286 kfree(hash);
1287}
1288
1289static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1290{
1291 struct ftrace_hash *hash;
1292
1293 hash = container_of(rcu, struct ftrace_hash, rcu);
1294 free_ftrace_hash(hash);
1295}
1296
1297static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1298{
1299 if (!hash || hash == EMPTY_HASH)
1300 return;
1301 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1302}
1303
1304/**
1305 * ftrace_free_filter - remove all filters for an ftrace_ops
1306 * @ops: the ops to remove the filters from
1307 */
1308void ftrace_free_filter(struct ftrace_ops *ops)
1309{
1310 ftrace_ops_init(ops);
1311 free_ftrace_hash(ops->func_hash->filter_hash);
1312 free_ftrace_hash(ops->func_hash->notrace_hash);
1313}
1314EXPORT_SYMBOL_GPL(ftrace_free_filter);
1315
1316static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1317{
1318 struct ftrace_hash *hash;
1319 int size;
1320
1321 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1322 if (!hash)
1323 return NULL;
1324
1325 size = 1 << size_bits;
1326 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1327
1328 if (!hash->buckets) {
1329 kfree(hash);
1330 return NULL;
1331 }
1332
1333 hash->size_bits = size_bits;
1334
1335 return hash;
1336}
1337
1338/* Used to save filters on functions for modules not loaded yet */
1339static int ftrace_add_mod(struct trace_array *tr,
1340 const char *func, const char *module,
1341 int enable)
1342{
1343 struct ftrace_mod_load *ftrace_mod;
1344 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1345
1346 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1347 if (!ftrace_mod)
1348 return -ENOMEM;
1349
1350 INIT_LIST_HEAD(&ftrace_mod->list);
1351 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1352 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1353 ftrace_mod->enable = enable;
1354
1355 if (!ftrace_mod->func || !ftrace_mod->module)
1356 goto out_free;
1357
1358 list_add(&ftrace_mod->list, mod_head);
1359
1360 return 0;
1361
1362 out_free:
1363 free_ftrace_mod(ftrace_mod);
1364
1365 return -ENOMEM;
1366}
1367
1368static struct ftrace_hash *
1369alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1370{
1371 struct ftrace_func_entry *entry;
1372 struct ftrace_hash *new_hash;
1373 int size;
1374 int i;
1375
1376 new_hash = alloc_ftrace_hash(size_bits);
1377 if (!new_hash)
1378 return NULL;
1379
1380 if (hash)
1381 new_hash->flags = hash->flags;
1382
1383 /* Empty hash? */
1384 if (ftrace_hash_empty(hash))
1385 return new_hash;
1386
1387 size = 1 << hash->size_bits;
1388 for (i = 0; i < size; i++) {
1389 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1390 if (add_hash_entry(new_hash, entry->ip) == NULL)
1391 goto free_hash;
1392 }
1393 }
1394
1395 FTRACE_WARN_ON(new_hash->count != hash->count);
1396
1397 return new_hash;
1398
1399 free_hash:
1400 free_ftrace_hash(new_hash);
1401 return NULL;
1402}
1403
1404static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops);
1405static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops);
1406
1407static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1408 struct ftrace_hash *new_hash);
1409
1410/*
1411 * Allocate a new hash and remove entries from @src and move them to the new hash.
1412 * On success, the @src hash will be empty and should be freed.
1413 */
1414static struct ftrace_hash *__move_hash(struct ftrace_hash *src, int size)
1415{
1416 struct ftrace_func_entry *entry;
1417 struct ftrace_hash *new_hash;
1418 struct hlist_head *hhd;
1419 struct hlist_node *tn;
1420 int bits = 0;
1421 int i;
1422
1423 /*
1424 * Use around half the size (max bit of it), but
1425 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1426 */
1427 bits = fls(size / 2);
1428
1429 /* Don't allocate too much */
1430 if (bits > FTRACE_HASH_MAX_BITS)
1431 bits = FTRACE_HASH_MAX_BITS;
1432
1433 new_hash = alloc_ftrace_hash(bits);
1434 if (!new_hash)
1435 return NULL;
1436
1437 new_hash->flags = src->flags;
1438
1439 size = 1 << src->size_bits;
1440 for (i = 0; i < size; i++) {
1441 hhd = &src->buckets[i];
1442 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1443 remove_hash_entry(src, entry);
1444 __add_hash_entry(new_hash, entry);
1445 }
1446 }
1447 return new_hash;
1448}
1449
1450/* Move the @src entries to a newly allocated hash */
1451static struct ftrace_hash *
1452__ftrace_hash_move(struct ftrace_hash *src)
1453{
1454 int size = src->count;
1455
1456 /*
1457 * If the new source is empty, just return the empty_hash.
1458 */
1459 if (ftrace_hash_empty(src))
1460 return EMPTY_HASH;
1461
1462 return __move_hash(src, size);
1463}
1464
1465/**
1466 * ftrace_hash_move - move a new hash to a filter and do updates
1467 * @ops: The ops with the hash that @dst points to
1468 * @enable: True if for the filter hash, false for the notrace hash
1469 * @dst: Points to the @ops hash that should be updated
1470 * @src: The hash to update @dst with
1471 *
1472 * This is called when an ftrace_ops hash is being updated and the
1473 * the kernel needs to reflect this. Note, this only updates the kernel
1474 * function callbacks if the @ops is enabled (not to be confused with
1475 * @enable above). If the @ops is enabled, its hash determines what
1476 * callbacks get called. This function gets called when the @ops hash
1477 * is updated and it requires new callbacks.
1478 *
1479 * On success the elements of @src is moved to @dst, and @dst is updated
1480 * properly, as well as the functions determined by the @ops hashes
1481 * are now calling the @ops callback function.
1482 *
1483 * Regardless of return type, @src should be freed with free_ftrace_hash().
1484 */
1485static int
1486ftrace_hash_move(struct ftrace_ops *ops, int enable,
1487 struct ftrace_hash **dst, struct ftrace_hash *src)
1488{
1489 struct ftrace_hash *new_hash;
1490 int ret;
1491
1492 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1493 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1494 return -EINVAL;
1495
1496 new_hash = __ftrace_hash_move(src);
1497 if (!new_hash)
1498 return -ENOMEM;
1499
1500 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1501 if (enable) {
1502 /* IPMODIFY should be updated only when filter_hash updating */
1503 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1504 if (ret < 0) {
1505 free_ftrace_hash(new_hash);
1506 return ret;
1507 }
1508 }
1509
1510 /*
1511 * Remove the current set, update the hash and add
1512 * them back.
1513 */
1514 ftrace_hash_rec_disable_modify(ops);
1515
1516 rcu_assign_pointer(*dst, new_hash);
1517
1518 ftrace_hash_rec_enable_modify(ops);
1519
1520 return 0;
1521}
1522
1523static bool hash_contains_ip(unsigned long ip,
1524 struct ftrace_ops_hash *hash)
1525{
1526 /*
1527 * The function record is a match if it exists in the filter
1528 * hash and not in the notrace hash. Note, an empty hash is
1529 * considered a match for the filter hash, but an empty
1530 * notrace hash is considered not in the notrace hash.
1531 */
1532 return (ftrace_hash_empty(hash->filter_hash) ||
1533 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1534 (ftrace_hash_empty(hash->notrace_hash) ||
1535 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1536}
1537
1538/*
1539 * Test the hashes for this ops to see if we want to call
1540 * the ops->func or not.
1541 *
1542 * It's a match if the ip is in the ops->filter_hash or
1543 * the filter_hash does not exist or is empty,
1544 * AND
1545 * the ip is not in the ops->notrace_hash.
1546 *
1547 * This needs to be called with preemption disabled as
1548 * the hashes are freed with call_rcu().
1549 */
1550int
1551ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1552{
1553 struct ftrace_ops_hash hash;
1554 int ret;
1555
1556#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1557 /*
1558 * There's a small race when adding ops that the ftrace handler
1559 * that wants regs, may be called without them. We can not
1560 * allow that handler to be called if regs is NULL.
1561 */
1562 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1563 return 0;
1564#endif
1565
1566 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1567 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1568
1569 if (hash_contains_ip(ip, &hash))
1570 ret = 1;
1571 else
1572 ret = 0;
1573
1574 return ret;
1575}
1576
1577/*
1578 * This is a double for. Do not use 'break' to break out of the loop,
1579 * you must use a goto.
1580 */
1581#define do_for_each_ftrace_rec(pg, rec) \
1582 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1583 int _____i; \
1584 for (_____i = 0; _____i < pg->index; _____i++) { \
1585 rec = &pg->records[_____i];
1586
1587#define while_for_each_ftrace_rec() \
1588 } \
1589 }
1590
1591
1592static int ftrace_cmp_recs(const void *a, const void *b)
1593{
1594 const struct dyn_ftrace *key = a;
1595 const struct dyn_ftrace *rec = b;
1596
1597 if (key->flags < rec->ip)
1598 return -1;
1599 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1600 return 1;
1601 return 0;
1602}
1603
1604static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1605{
1606 struct ftrace_page *pg;
1607 struct dyn_ftrace *rec = NULL;
1608 struct dyn_ftrace key;
1609
1610 key.ip = start;
1611 key.flags = end; /* overload flags, as it is unsigned long */
1612
1613 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1614 if (pg->index == 0 ||
1615 end < pg->records[0].ip ||
1616 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1617 continue;
1618 rec = bsearch(&key, pg->records, pg->index,
1619 sizeof(struct dyn_ftrace),
1620 ftrace_cmp_recs);
1621 if (rec)
1622 break;
1623 }
1624 return rec;
1625}
1626
1627/**
1628 * ftrace_location_range - return the first address of a traced location
1629 * if it touches the given ip range
1630 * @start: start of range to search.
1631 * @end: end of range to search (inclusive). @end points to the last byte
1632 * to check.
1633 *
1634 * Returns: rec->ip if the related ftrace location is a least partly within
1635 * the given address range. That is, the first address of the instruction
1636 * that is either a NOP or call to the function tracer. It checks the ftrace
1637 * internal tables to determine if the address belongs or not.
1638 */
1639unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1640{
1641 struct dyn_ftrace *rec;
1642 unsigned long ip = 0;
1643
1644 rcu_read_lock();
1645 rec = lookup_rec(start, end);
1646 if (rec)
1647 ip = rec->ip;
1648 rcu_read_unlock();
1649
1650 return ip;
1651}
1652
1653/**
1654 * ftrace_location - return the ftrace location
1655 * @ip: the instruction pointer to check
1656 *
1657 * Returns:
1658 * * If @ip matches the ftrace location, return @ip.
1659 * * If @ip matches sym+0, return sym's ftrace location.
1660 * * Otherwise, return 0.
1661 */
1662unsigned long ftrace_location(unsigned long ip)
1663{
1664 unsigned long loc;
1665 unsigned long offset;
1666 unsigned long size;
1667
1668 loc = ftrace_location_range(ip, ip);
1669 if (!loc) {
1670 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1671 goto out;
1672
1673 /* map sym+0 to __fentry__ */
1674 if (!offset)
1675 loc = ftrace_location_range(ip, ip + size - 1);
1676 }
1677
1678out:
1679 return loc;
1680}
1681
1682/**
1683 * ftrace_text_reserved - return true if range contains an ftrace location
1684 * @start: start of range to search
1685 * @end: end of range to search (inclusive). @end points to the last byte to check.
1686 *
1687 * Returns: 1 if @start and @end contains a ftrace location.
1688 * That is, the instruction that is either a NOP or call to
1689 * the function tracer. It checks the ftrace internal tables to
1690 * determine if the address belongs or not.
1691 */
1692int ftrace_text_reserved(const void *start, const void *end)
1693{
1694 unsigned long ret;
1695
1696 ret = ftrace_location_range((unsigned long)start,
1697 (unsigned long)end);
1698
1699 return (int)!!ret;
1700}
1701
1702/* Test if ops registered to this rec needs regs */
1703static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1704{
1705 struct ftrace_ops *ops;
1706 bool keep_regs = false;
1707
1708 for (ops = ftrace_ops_list;
1709 ops != &ftrace_list_end; ops = ops->next) {
1710 /* pass rec in as regs to have non-NULL val */
1711 if (ftrace_ops_test(ops, rec->ip, rec)) {
1712 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1713 keep_regs = true;
1714 break;
1715 }
1716 }
1717 }
1718
1719 return keep_regs;
1720}
1721
1722static struct ftrace_ops *
1723ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1724static struct ftrace_ops *
1725ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1726static struct ftrace_ops *
1727ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1728
1729static bool skip_record(struct dyn_ftrace *rec)
1730{
1731 /*
1732 * At boot up, weak functions are set to disable. Function tracing
1733 * can be enabled before they are, and they still need to be disabled now.
1734 * If the record is disabled, still continue if it is marked as already
1735 * enabled (this is needed to keep the accounting working).
1736 */
1737 return rec->flags & FTRACE_FL_DISABLED &&
1738 !(rec->flags & FTRACE_FL_ENABLED);
1739}
1740
1741/*
1742 * This is the main engine to the ftrace updates to the dyn_ftrace records.
1743 *
1744 * It will iterate through all the available ftrace functions
1745 * (the ones that ftrace can have callbacks to) and set the flags
1746 * in the associated dyn_ftrace records.
1747 *
1748 * @inc: If true, the functions associated to @ops are added to
1749 * the dyn_ftrace records, otherwise they are removed.
1750 */
1751static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1752 bool inc)
1753{
1754 struct ftrace_hash *hash;
1755 struct ftrace_hash *notrace_hash;
1756 struct ftrace_page *pg;
1757 struct dyn_ftrace *rec;
1758 bool update = false;
1759 int count = 0;
1760 int all = false;
1761
1762 /* Only update if the ops has been registered */
1763 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1764 return false;
1765
1766 /*
1767 * If the count is zero, we update all records.
1768 * Otherwise we just update the items in the hash.
1769 */
1770 hash = ops->func_hash->filter_hash;
1771 notrace_hash = ops->func_hash->notrace_hash;
1772 if (ftrace_hash_empty(hash))
1773 all = true;
1774
1775 do_for_each_ftrace_rec(pg, rec) {
1776 int in_notrace_hash = 0;
1777 int in_hash = 0;
1778 int match = 0;
1779
1780 if (skip_record(rec))
1781 continue;
1782
1783 if (all) {
1784 /*
1785 * Only the filter_hash affects all records.
1786 * Update if the record is not in the notrace hash.
1787 */
1788 if (!notrace_hash || !ftrace_lookup_ip(notrace_hash, rec->ip))
1789 match = 1;
1790 } else {
1791 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1792 in_notrace_hash = !!ftrace_lookup_ip(notrace_hash, rec->ip);
1793
1794 /*
1795 * We want to match all functions that are in the hash but
1796 * not in the other hash.
1797 */
1798 if (in_hash && !in_notrace_hash)
1799 match = 1;
1800 }
1801 if (!match)
1802 continue;
1803
1804 if (inc) {
1805 rec->flags++;
1806 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1807 return false;
1808
1809 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1810 rec->flags |= FTRACE_FL_DIRECT;
1811
1812 /*
1813 * If there's only a single callback registered to a
1814 * function, and the ops has a trampoline registered
1815 * for it, then we can call it directly.
1816 */
1817 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1818 rec->flags |= FTRACE_FL_TRAMP;
1819 else
1820 /*
1821 * If we are adding another function callback
1822 * to this function, and the previous had a
1823 * custom trampoline in use, then we need to go
1824 * back to the default trampoline.
1825 */
1826 rec->flags &= ~FTRACE_FL_TRAMP;
1827
1828 /*
1829 * If any ops wants regs saved for this function
1830 * then all ops will get saved regs.
1831 */
1832 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1833 rec->flags |= FTRACE_FL_REGS;
1834 } else {
1835 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1836 return false;
1837 rec->flags--;
1838
1839 /*
1840 * Only the internal direct_ops should have the
1841 * DIRECT flag set. Thus, if it is removing a
1842 * function, then that function should no longer
1843 * be direct.
1844 */
1845 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1846 rec->flags &= ~FTRACE_FL_DIRECT;
1847
1848 /*
1849 * If the rec had REGS enabled and the ops that is
1850 * being removed had REGS set, then see if there is
1851 * still any ops for this record that wants regs.
1852 * If not, we can stop recording them.
1853 */
1854 if (ftrace_rec_count(rec) > 0 &&
1855 rec->flags & FTRACE_FL_REGS &&
1856 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1857 if (!test_rec_ops_needs_regs(rec))
1858 rec->flags &= ~FTRACE_FL_REGS;
1859 }
1860
1861 /*
1862 * The TRAMP needs to be set only if rec count
1863 * is decremented to one, and the ops that is
1864 * left has a trampoline. As TRAMP can only be
1865 * enabled if there is only a single ops attached
1866 * to it.
1867 */
1868 if (ftrace_rec_count(rec) == 1 &&
1869 ftrace_find_tramp_ops_any_other(rec, ops))
1870 rec->flags |= FTRACE_FL_TRAMP;
1871 else
1872 rec->flags &= ~FTRACE_FL_TRAMP;
1873
1874 /*
1875 * flags will be cleared in ftrace_check_record()
1876 * if rec count is zero.
1877 */
1878 }
1879
1880 /*
1881 * If the rec has a single associated ops, and ops->func can be
1882 * called directly, allow the call site to call via the ops.
1883 */
1884 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1885 ftrace_rec_count(rec) == 1 &&
1886 ftrace_ops_get_func(ops) == ops->func)
1887 rec->flags |= FTRACE_FL_CALL_OPS;
1888 else
1889 rec->flags &= ~FTRACE_FL_CALL_OPS;
1890
1891 count++;
1892
1893 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1894 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1895
1896 /* Shortcut, if we handled all records, we are done. */
1897 if (!all && count == hash->count)
1898 return update;
1899 } while_for_each_ftrace_rec();
1900
1901 return update;
1902}
1903
1904/*
1905 * This is called when an ops is removed from tracing. It will decrement
1906 * the counters of the dyn_ftrace records for all the functions that
1907 * the @ops attached to.
1908 */
1909static bool ftrace_hash_rec_disable(struct ftrace_ops *ops)
1910{
1911 return __ftrace_hash_rec_update(ops, false);
1912}
1913
1914/*
1915 * This is called when an ops is added to tracing. It will increment
1916 * the counters of the dyn_ftrace records for all the functions that
1917 * the @ops attached to.
1918 */
1919static bool ftrace_hash_rec_enable(struct ftrace_ops *ops)
1920{
1921 return __ftrace_hash_rec_update(ops, true);
1922}
1923
1924/*
1925 * This function will update what functions @ops traces when its filter
1926 * changes.
1927 *
1928 * The @inc states if the @ops callbacks are going to be added or removed.
1929 * When one of the @ops hashes are updated to a "new_hash" the dyn_ftrace
1930 * records are update via:
1931 *
1932 * ftrace_hash_rec_disable_modify(ops);
1933 * ops->hash = new_hash
1934 * ftrace_hash_rec_enable_modify(ops);
1935 *
1936 * Where the @ops is removed from all the records it is tracing using
1937 * its old hash. The @ops hash is updated to the new hash, and then
1938 * the @ops is added back to the records so that it is tracing all
1939 * the new functions.
1940 */
1941static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, bool inc)
1942{
1943 struct ftrace_ops *op;
1944
1945 __ftrace_hash_rec_update(ops, inc);
1946
1947 if (ops->func_hash != &global_ops.local_hash)
1948 return;
1949
1950 /*
1951 * If the ops shares the global_ops hash, then we need to update
1952 * all ops that are enabled and use this hash.
1953 */
1954 do_for_each_ftrace_op(op, ftrace_ops_list) {
1955 /* Already done */
1956 if (op == ops)
1957 continue;
1958 if (op->func_hash == &global_ops.local_hash)
1959 __ftrace_hash_rec_update(op, inc);
1960 } while_for_each_ftrace_op(op);
1961}
1962
1963static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops)
1964{
1965 ftrace_hash_rec_update_modify(ops, false);
1966}
1967
1968static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops)
1969{
1970 ftrace_hash_rec_update_modify(ops, true);
1971}
1972
1973/*
1974 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1975 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1976 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1977 * Note that old_hash and new_hash has below meanings
1978 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1979 * - If the hash is EMPTY_HASH, it hits nothing
1980 * - Anything else hits the recs which match the hash entries.
1981 *
1982 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1983 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1984 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1985 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1986 * the return value to the caller and eventually to the owner of the DIRECT
1987 * ops.
1988 */
1989static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1990 struct ftrace_hash *old_hash,
1991 struct ftrace_hash *new_hash)
1992{
1993 struct ftrace_page *pg;
1994 struct dyn_ftrace *rec, *end = NULL;
1995 int in_old, in_new;
1996 bool is_ipmodify, is_direct;
1997
1998 /* Only update if the ops has been registered */
1999 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2000 return 0;
2001
2002 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
2003 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
2004
2005 /* neither IPMODIFY nor DIRECT, skip */
2006 if (!is_ipmodify && !is_direct)
2007 return 0;
2008
2009 if (WARN_ON_ONCE(is_ipmodify && is_direct))
2010 return 0;
2011
2012 /*
2013 * Since the IPMODIFY and DIRECT are very address sensitive
2014 * actions, we do not allow ftrace_ops to set all functions to new
2015 * hash.
2016 */
2017 if (!new_hash || !old_hash)
2018 return -EINVAL;
2019
2020 /* Update rec->flags */
2021 do_for_each_ftrace_rec(pg, rec) {
2022
2023 if (rec->flags & FTRACE_FL_DISABLED)
2024 continue;
2025
2026 /* We need to update only differences of filter_hash */
2027 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2028 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2029 if (in_old == in_new)
2030 continue;
2031
2032 if (in_new) {
2033 if (rec->flags & FTRACE_FL_IPMODIFY) {
2034 int ret;
2035
2036 /* Cannot have two ipmodify on same rec */
2037 if (is_ipmodify)
2038 goto rollback;
2039
2040 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
2041
2042 /*
2043 * Another ops with IPMODIFY is already
2044 * attached. We are now attaching a direct
2045 * ops. Run SHARE_IPMODIFY_SELF, to check
2046 * whether sharing is supported.
2047 */
2048 if (!ops->ops_func)
2049 return -EBUSY;
2050 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2051 if (ret)
2052 return ret;
2053 } else if (is_ipmodify) {
2054 rec->flags |= FTRACE_FL_IPMODIFY;
2055 }
2056 } else if (is_ipmodify) {
2057 rec->flags &= ~FTRACE_FL_IPMODIFY;
2058 }
2059 } while_for_each_ftrace_rec();
2060
2061 return 0;
2062
2063rollback:
2064 end = rec;
2065
2066 /* Roll back what we did above */
2067 do_for_each_ftrace_rec(pg, rec) {
2068
2069 if (rec->flags & FTRACE_FL_DISABLED)
2070 continue;
2071
2072 if (rec == end)
2073 goto err_out;
2074
2075 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2076 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2077 if (in_old == in_new)
2078 continue;
2079
2080 if (in_new)
2081 rec->flags &= ~FTRACE_FL_IPMODIFY;
2082 else
2083 rec->flags |= FTRACE_FL_IPMODIFY;
2084 } while_for_each_ftrace_rec();
2085
2086err_out:
2087 return -EBUSY;
2088}
2089
2090static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2091{
2092 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2093
2094 if (ftrace_hash_empty(hash))
2095 hash = NULL;
2096
2097 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2098}
2099
2100/* Disabling always succeeds */
2101static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2102{
2103 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2104
2105 if (ftrace_hash_empty(hash))
2106 hash = NULL;
2107
2108 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2109}
2110
2111static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2112 struct ftrace_hash *new_hash)
2113{
2114 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2115
2116 if (ftrace_hash_empty(old_hash))
2117 old_hash = NULL;
2118
2119 if (ftrace_hash_empty(new_hash))
2120 new_hash = NULL;
2121
2122 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2123}
2124
2125static void print_ip_ins(const char *fmt, const unsigned char *p)
2126{
2127 char ins[MCOUNT_INSN_SIZE];
2128
2129 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2130 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2131 return;
2132 }
2133
2134 printk(KERN_CONT "%s", fmt);
2135 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2136}
2137
2138enum ftrace_bug_type ftrace_bug_type;
2139const void *ftrace_expected;
2140
2141static void print_bug_type(void)
2142{
2143 switch (ftrace_bug_type) {
2144 case FTRACE_BUG_UNKNOWN:
2145 break;
2146 case FTRACE_BUG_INIT:
2147 pr_info("Initializing ftrace call sites\n");
2148 break;
2149 case FTRACE_BUG_NOP:
2150 pr_info("Setting ftrace call site to NOP\n");
2151 break;
2152 case FTRACE_BUG_CALL:
2153 pr_info("Setting ftrace call site to call ftrace function\n");
2154 break;
2155 case FTRACE_BUG_UPDATE:
2156 pr_info("Updating ftrace call site to call a different ftrace function\n");
2157 break;
2158 }
2159}
2160
2161/**
2162 * ftrace_bug - report and shutdown function tracer
2163 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2164 * @rec: The record that failed
2165 *
2166 * The arch code that enables or disables the function tracing
2167 * can call ftrace_bug() when it has detected a problem in
2168 * modifying the code. @failed should be one of either:
2169 * EFAULT - if the problem happens on reading the @ip address
2170 * EINVAL - if what is read at @ip is not what was expected
2171 * EPERM - if the problem happens on writing to the @ip address
2172 */
2173void ftrace_bug(int failed, struct dyn_ftrace *rec)
2174{
2175 unsigned long ip = rec ? rec->ip : 0;
2176
2177 pr_info("------------[ ftrace bug ]------------\n");
2178
2179 switch (failed) {
2180 case -EFAULT:
2181 pr_info("ftrace faulted on modifying ");
2182 print_ip_sym(KERN_INFO, ip);
2183 break;
2184 case -EINVAL:
2185 pr_info("ftrace failed to modify ");
2186 print_ip_sym(KERN_INFO, ip);
2187 print_ip_ins(" actual: ", (unsigned char *)ip);
2188 pr_cont("\n");
2189 if (ftrace_expected) {
2190 print_ip_ins(" expected: ", ftrace_expected);
2191 pr_cont("\n");
2192 }
2193 break;
2194 case -EPERM:
2195 pr_info("ftrace faulted on writing ");
2196 print_ip_sym(KERN_INFO, ip);
2197 break;
2198 default:
2199 pr_info("ftrace faulted on unknown error ");
2200 print_ip_sym(KERN_INFO, ip);
2201 }
2202 print_bug_type();
2203 if (rec) {
2204 struct ftrace_ops *ops = NULL;
2205
2206 pr_info("ftrace record flags: %lx\n", rec->flags);
2207 pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2208 rec->flags & FTRACE_FL_REGS ? " R" : " ",
2209 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ");
2210 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2211 ops = ftrace_find_tramp_ops_any(rec);
2212 if (ops) {
2213 do {
2214 pr_cont("\ttramp: %pS (%pS)",
2215 (void *)ops->trampoline,
2216 (void *)ops->func);
2217 ops = ftrace_find_tramp_ops_next(rec, ops);
2218 } while (ops);
2219 } else
2220 pr_cont("\ttramp: ERROR!");
2221
2222 }
2223 ip = ftrace_get_addr_curr(rec);
2224 pr_cont("\n expected tramp: %lx\n", ip);
2225 }
2226
2227 FTRACE_WARN_ON_ONCE(1);
2228}
2229
2230static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2231{
2232 unsigned long flag = 0UL;
2233
2234 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2235
2236 if (skip_record(rec))
2237 return FTRACE_UPDATE_IGNORE;
2238
2239 /*
2240 * If we are updating calls:
2241 *
2242 * If the record has a ref count, then we need to enable it
2243 * because someone is using it.
2244 *
2245 * Otherwise we make sure its disabled.
2246 *
2247 * If we are disabling calls, then disable all records that
2248 * are enabled.
2249 */
2250 if (enable && ftrace_rec_count(rec))
2251 flag = FTRACE_FL_ENABLED;
2252
2253 /*
2254 * If enabling and the REGS flag does not match the REGS_EN, or
2255 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2256 * this record. Set flags to fail the compare against ENABLED.
2257 * Same for direct calls.
2258 */
2259 if (flag) {
2260 if (!(rec->flags & FTRACE_FL_REGS) !=
2261 !(rec->flags & FTRACE_FL_REGS_EN))
2262 flag |= FTRACE_FL_REGS;
2263
2264 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2265 !(rec->flags & FTRACE_FL_TRAMP_EN))
2266 flag |= FTRACE_FL_TRAMP;
2267
2268 /*
2269 * Direct calls are special, as count matters.
2270 * We must test the record for direct, if the
2271 * DIRECT and DIRECT_EN do not match, but only
2272 * if the count is 1. That's because, if the
2273 * count is something other than one, we do not
2274 * want the direct enabled (it will be done via the
2275 * direct helper). But if DIRECT_EN is set, and
2276 * the count is not one, we need to clear it.
2277 *
2278 */
2279 if (ftrace_rec_count(rec) == 1) {
2280 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2281 !(rec->flags & FTRACE_FL_DIRECT_EN))
2282 flag |= FTRACE_FL_DIRECT;
2283 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2284 flag |= FTRACE_FL_DIRECT;
2285 }
2286
2287 /*
2288 * Ops calls are special, as count matters.
2289 * As with direct calls, they must only be enabled when count
2290 * is one, otherwise they'll be handled via the list ops.
2291 */
2292 if (ftrace_rec_count(rec) == 1) {
2293 if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2294 !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2295 flag |= FTRACE_FL_CALL_OPS;
2296 } else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2297 flag |= FTRACE_FL_CALL_OPS;
2298 }
2299 }
2300
2301 /* If the state of this record hasn't changed, then do nothing */
2302 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2303 return FTRACE_UPDATE_IGNORE;
2304
2305 if (flag) {
2306 /* Save off if rec is being enabled (for return value) */
2307 flag ^= rec->flags & FTRACE_FL_ENABLED;
2308
2309 if (update) {
2310 rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2311 if (flag & FTRACE_FL_REGS) {
2312 if (rec->flags & FTRACE_FL_REGS)
2313 rec->flags |= FTRACE_FL_REGS_EN;
2314 else
2315 rec->flags &= ~FTRACE_FL_REGS_EN;
2316 }
2317 if (flag & FTRACE_FL_TRAMP) {
2318 if (rec->flags & FTRACE_FL_TRAMP)
2319 rec->flags |= FTRACE_FL_TRAMP_EN;
2320 else
2321 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2322 }
2323
2324 /* Keep track of anything that modifies the function */
2325 if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2326 rec->flags |= FTRACE_FL_MODIFIED;
2327
2328 if (flag & FTRACE_FL_DIRECT) {
2329 /*
2330 * If there's only one user (direct_ops helper)
2331 * then we can call the direct function
2332 * directly (no ftrace trampoline).
2333 */
2334 if (ftrace_rec_count(rec) == 1) {
2335 if (rec->flags & FTRACE_FL_DIRECT)
2336 rec->flags |= FTRACE_FL_DIRECT_EN;
2337 else
2338 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2339 } else {
2340 /*
2341 * Can only call directly if there's
2342 * only one callback to the function.
2343 */
2344 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2345 }
2346 }
2347
2348 if (flag & FTRACE_FL_CALL_OPS) {
2349 if (ftrace_rec_count(rec) == 1) {
2350 if (rec->flags & FTRACE_FL_CALL_OPS)
2351 rec->flags |= FTRACE_FL_CALL_OPS_EN;
2352 else
2353 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2354 } else {
2355 /*
2356 * Can only call directly if there's
2357 * only one set of associated ops.
2358 */
2359 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2360 }
2361 }
2362 }
2363
2364 /*
2365 * If this record is being updated from a nop, then
2366 * return UPDATE_MAKE_CALL.
2367 * Otherwise,
2368 * return UPDATE_MODIFY_CALL to tell the caller to convert
2369 * from the save regs, to a non-save regs function or
2370 * vice versa, or from a trampoline call.
2371 */
2372 if (flag & FTRACE_FL_ENABLED) {
2373 ftrace_bug_type = FTRACE_BUG_CALL;
2374 return FTRACE_UPDATE_MAKE_CALL;
2375 }
2376
2377 ftrace_bug_type = FTRACE_BUG_UPDATE;
2378 return FTRACE_UPDATE_MODIFY_CALL;
2379 }
2380
2381 if (update) {
2382 /* If there's no more users, clear all flags */
2383 if (!ftrace_rec_count(rec))
2384 rec->flags &= FTRACE_NOCLEAR_FLAGS;
2385 else
2386 /*
2387 * Just disable the record, but keep the ops TRAMP
2388 * and REGS states. The _EN flags must be disabled though.
2389 */
2390 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2391 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2392 FTRACE_FL_CALL_OPS_EN);
2393 }
2394
2395 ftrace_bug_type = FTRACE_BUG_NOP;
2396 return FTRACE_UPDATE_MAKE_NOP;
2397}
2398
2399/**
2400 * ftrace_update_record - set a record that now is tracing or not
2401 * @rec: the record to update
2402 * @enable: set to true if the record is tracing, false to force disable
2403 *
2404 * The records that represent all functions that can be traced need
2405 * to be updated when tracing has been enabled.
2406 */
2407int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2408{
2409 return ftrace_check_record(rec, enable, true);
2410}
2411
2412/**
2413 * ftrace_test_record - check if the record has been enabled or not
2414 * @rec: the record to test
2415 * @enable: set to true to check if enabled, false if it is disabled
2416 *
2417 * The arch code may need to test if a record is already set to
2418 * tracing to determine how to modify the function code that it
2419 * represents.
2420 */
2421int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2422{
2423 return ftrace_check_record(rec, enable, false);
2424}
2425
2426static struct ftrace_ops *
2427ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2428{
2429 struct ftrace_ops *op;
2430 unsigned long ip = rec->ip;
2431
2432 do_for_each_ftrace_op(op, ftrace_ops_list) {
2433
2434 if (!op->trampoline)
2435 continue;
2436
2437 if (hash_contains_ip(ip, op->func_hash))
2438 return op;
2439 } while_for_each_ftrace_op(op);
2440
2441 return NULL;
2442}
2443
2444static struct ftrace_ops *
2445ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2446{
2447 struct ftrace_ops *op;
2448 unsigned long ip = rec->ip;
2449
2450 do_for_each_ftrace_op(op, ftrace_ops_list) {
2451
2452 if (op == op_exclude || !op->trampoline)
2453 continue;
2454
2455 if (hash_contains_ip(ip, op->func_hash))
2456 return op;
2457 } while_for_each_ftrace_op(op);
2458
2459 return NULL;
2460}
2461
2462static struct ftrace_ops *
2463ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2464 struct ftrace_ops *op)
2465{
2466 unsigned long ip = rec->ip;
2467
2468 while_for_each_ftrace_op(op) {
2469
2470 if (!op->trampoline)
2471 continue;
2472
2473 if (hash_contains_ip(ip, op->func_hash))
2474 return op;
2475 }
2476
2477 return NULL;
2478}
2479
2480static struct ftrace_ops *
2481ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2482{
2483 struct ftrace_ops *op;
2484 unsigned long ip = rec->ip;
2485
2486 /*
2487 * Need to check removed ops first.
2488 * If they are being removed, and this rec has a tramp,
2489 * and this rec is in the ops list, then it would be the
2490 * one with the tramp.
2491 */
2492 if (removed_ops) {
2493 if (hash_contains_ip(ip, &removed_ops->old_hash))
2494 return removed_ops;
2495 }
2496
2497 /*
2498 * Need to find the current trampoline for a rec.
2499 * Now, a trampoline is only attached to a rec if there
2500 * was a single 'ops' attached to it. But this can be called
2501 * when we are adding another op to the rec or removing the
2502 * current one. Thus, if the op is being added, we can
2503 * ignore it because it hasn't attached itself to the rec
2504 * yet.
2505 *
2506 * If an ops is being modified (hooking to different functions)
2507 * then we don't care about the new functions that are being
2508 * added, just the old ones (that are probably being removed).
2509 *
2510 * If we are adding an ops to a function that already is using
2511 * a trampoline, it needs to be removed (trampolines are only
2512 * for single ops connected), then an ops that is not being
2513 * modified also needs to be checked.
2514 */
2515 do_for_each_ftrace_op(op, ftrace_ops_list) {
2516
2517 if (!op->trampoline)
2518 continue;
2519
2520 /*
2521 * If the ops is being added, it hasn't gotten to
2522 * the point to be removed from this tree yet.
2523 */
2524 if (op->flags & FTRACE_OPS_FL_ADDING)
2525 continue;
2526
2527
2528 /*
2529 * If the ops is being modified and is in the old
2530 * hash, then it is probably being removed from this
2531 * function.
2532 */
2533 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2534 hash_contains_ip(ip, &op->old_hash))
2535 return op;
2536 /*
2537 * If the ops is not being added or modified, and it's
2538 * in its normal filter hash, then this must be the one
2539 * we want!
2540 */
2541 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2542 hash_contains_ip(ip, op->func_hash))
2543 return op;
2544
2545 } while_for_each_ftrace_op(op);
2546
2547 return NULL;
2548}
2549
2550static struct ftrace_ops *
2551ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2552{
2553 struct ftrace_ops *op;
2554 unsigned long ip = rec->ip;
2555
2556 do_for_each_ftrace_op(op, ftrace_ops_list) {
2557 /* pass rec in as regs to have non-NULL val */
2558 if (hash_contains_ip(ip, op->func_hash))
2559 return op;
2560 } while_for_each_ftrace_op(op);
2561
2562 return NULL;
2563}
2564
2565struct ftrace_ops *
2566ftrace_find_unique_ops(struct dyn_ftrace *rec)
2567{
2568 struct ftrace_ops *op, *found = NULL;
2569 unsigned long ip = rec->ip;
2570
2571 do_for_each_ftrace_op(op, ftrace_ops_list) {
2572
2573 if (hash_contains_ip(ip, op->func_hash)) {
2574 if (found)
2575 return NULL;
2576 found = op;
2577 }
2578
2579 } while_for_each_ftrace_op(op);
2580
2581 return found;
2582}
2583
2584#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2585/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2586static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
2587static DEFINE_MUTEX(direct_mutex);
2588
2589/*
2590 * Search the direct_functions hash to see if the given instruction pointer
2591 * has a direct caller attached to it.
2592 */
2593unsigned long ftrace_find_rec_direct(unsigned long ip)
2594{
2595 struct ftrace_func_entry *entry;
2596
2597 entry = __ftrace_lookup_ip(direct_functions, ip);
2598 if (!entry)
2599 return 0;
2600
2601 return entry->direct;
2602}
2603
2604static void call_direct_funcs(unsigned long ip, unsigned long pip,
2605 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2606{
2607 unsigned long addr = READ_ONCE(ops->direct_call);
2608
2609 if (!addr)
2610 return;
2611
2612 arch_ftrace_set_direct_caller(fregs, addr);
2613}
2614#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2615
2616/**
2617 * ftrace_get_addr_new - Get the call address to set to
2618 * @rec: The ftrace record descriptor
2619 *
2620 * If the record has the FTRACE_FL_REGS set, that means that it
2621 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2622 * is not set, then it wants to convert to the normal callback.
2623 *
2624 * Returns: the address of the trampoline to set to
2625 */
2626unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2627{
2628 struct ftrace_ops *ops;
2629 unsigned long addr;
2630
2631 if ((rec->flags & FTRACE_FL_DIRECT) &&
2632 (ftrace_rec_count(rec) == 1)) {
2633 addr = ftrace_find_rec_direct(rec->ip);
2634 if (addr)
2635 return addr;
2636 WARN_ON_ONCE(1);
2637 }
2638
2639 /* Trampolines take precedence over regs */
2640 if (rec->flags & FTRACE_FL_TRAMP) {
2641 ops = ftrace_find_tramp_ops_new(rec);
2642 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2643 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2644 (void *)rec->ip, (void *)rec->ip, rec->flags);
2645 /* Ftrace is shutting down, return anything */
2646 return (unsigned long)FTRACE_ADDR;
2647 }
2648 return ops->trampoline;
2649 }
2650
2651 if (rec->flags & FTRACE_FL_REGS)
2652 return (unsigned long)FTRACE_REGS_ADDR;
2653 else
2654 return (unsigned long)FTRACE_ADDR;
2655}
2656
2657/**
2658 * ftrace_get_addr_curr - Get the call address that is already there
2659 * @rec: The ftrace record descriptor
2660 *
2661 * The FTRACE_FL_REGS_EN is set when the record already points to
2662 * a function that saves all the regs. Basically the '_EN' version
2663 * represents the current state of the function.
2664 *
2665 * Returns: the address of the trampoline that is currently being called
2666 */
2667unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2668{
2669 struct ftrace_ops *ops;
2670 unsigned long addr;
2671
2672 /* Direct calls take precedence over trampolines */
2673 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2674 addr = ftrace_find_rec_direct(rec->ip);
2675 if (addr)
2676 return addr;
2677 WARN_ON_ONCE(1);
2678 }
2679
2680 /* Trampolines take precedence over regs */
2681 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2682 ops = ftrace_find_tramp_ops_curr(rec);
2683 if (FTRACE_WARN_ON(!ops)) {
2684 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2685 (void *)rec->ip, (void *)rec->ip);
2686 /* Ftrace is shutting down, return anything */
2687 return (unsigned long)FTRACE_ADDR;
2688 }
2689 return ops->trampoline;
2690 }
2691
2692 if (rec->flags & FTRACE_FL_REGS_EN)
2693 return (unsigned long)FTRACE_REGS_ADDR;
2694 else
2695 return (unsigned long)FTRACE_ADDR;
2696}
2697
2698static int
2699__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2700{
2701 unsigned long ftrace_old_addr;
2702 unsigned long ftrace_addr;
2703 int ret;
2704
2705 ftrace_addr = ftrace_get_addr_new(rec);
2706
2707 /* This needs to be done before we call ftrace_update_record */
2708 ftrace_old_addr = ftrace_get_addr_curr(rec);
2709
2710 ret = ftrace_update_record(rec, enable);
2711
2712 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2713
2714 switch (ret) {
2715 case FTRACE_UPDATE_IGNORE:
2716 return 0;
2717
2718 case FTRACE_UPDATE_MAKE_CALL:
2719 ftrace_bug_type = FTRACE_BUG_CALL;
2720 return ftrace_make_call(rec, ftrace_addr);
2721
2722 case FTRACE_UPDATE_MAKE_NOP:
2723 ftrace_bug_type = FTRACE_BUG_NOP;
2724 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2725
2726 case FTRACE_UPDATE_MODIFY_CALL:
2727 ftrace_bug_type = FTRACE_BUG_UPDATE;
2728 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2729 }
2730
2731 return -1; /* unknown ftrace bug */
2732}
2733
2734void __weak ftrace_replace_code(int mod_flags)
2735{
2736 struct dyn_ftrace *rec;
2737 struct ftrace_page *pg;
2738 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2739 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2740 int failed;
2741
2742 if (unlikely(ftrace_disabled))
2743 return;
2744
2745 do_for_each_ftrace_rec(pg, rec) {
2746
2747 if (skip_record(rec))
2748 continue;
2749
2750 failed = __ftrace_replace_code(rec, enable);
2751 if (failed) {
2752 ftrace_bug(failed, rec);
2753 /* Stop processing */
2754 return;
2755 }
2756 if (schedulable)
2757 cond_resched();
2758 } while_for_each_ftrace_rec();
2759}
2760
2761struct ftrace_rec_iter {
2762 struct ftrace_page *pg;
2763 int index;
2764};
2765
2766/**
2767 * ftrace_rec_iter_start - start up iterating over traced functions
2768 *
2769 * Returns: an iterator handle that is used to iterate over all
2770 * the records that represent address locations where functions
2771 * are traced.
2772 *
2773 * May return NULL if no records are available.
2774 */
2775struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2776{
2777 /*
2778 * We only use a single iterator.
2779 * Protected by the ftrace_lock mutex.
2780 */
2781 static struct ftrace_rec_iter ftrace_rec_iter;
2782 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2783
2784 iter->pg = ftrace_pages_start;
2785 iter->index = 0;
2786
2787 /* Could have empty pages */
2788 while (iter->pg && !iter->pg->index)
2789 iter->pg = iter->pg->next;
2790
2791 if (!iter->pg)
2792 return NULL;
2793
2794 return iter;
2795}
2796
2797/**
2798 * ftrace_rec_iter_next - get the next record to process.
2799 * @iter: The handle to the iterator.
2800 *
2801 * Returns: the next iterator after the given iterator @iter.
2802 */
2803struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2804{
2805 iter->index++;
2806
2807 if (iter->index >= iter->pg->index) {
2808 iter->pg = iter->pg->next;
2809 iter->index = 0;
2810
2811 /* Could have empty pages */
2812 while (iter->pg && !iter->pg->index)
2813 iter->pg = iter->pg->next;
2814 }
2815
2816 if (!iter->pg)
2817 return NULL;
2818
2819 return iter;
2820}
2821
2822/**
2823 * ftrace_rec_iter_record - get the record at the iterator location
2824 * @iter: The current iterator location
2825 *
2826 * Returns: the record that the current @iter is at.
2827 */
2828struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2829{
2830 return &iter->pg->records[iter->index];
2831}
2832
2833static int
2834ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2835{
2836 int ret;
2837
2838 if (unlikely(ftrace_disabled))
2839 return 0;
2840
2841 ret = ftrace_init_nop(mod, rec);
2842 if (ret) {
2843 ftrace_bug_type = FTRACE_BUG_INIT;
2844 ftrace_bug(ret, rec);
2845 return 0;
2846 }
2847 return 1;
2848}
2849
2850/*
2851 * archs can override this function if they must do something
2852 * before the modifying code is performed.
2853 */
2854void __weak ftrace_arch_code_modify_prepare(void)
2855{
2856}
2857
2858/*
2859 * archs can override this function if they must do something
2860 * after the modifying code is performed.
2861 */
2862void __weak ftrace_arch_code_modify_post_process(void)
2863{
2864}
2865
2866static int update_ftrace_func(ftrace_func_t func)
2867{
2868 static ftrace_func_t save_func;
2869
2870 /* Avoid updating if it hasn't changed */
2871 if (func == save_func)
2872 return 0;
2873
2874 save_func = func;
2875
2876 return ftrace_update_ftrace_func(func);
2877}
2878
2879void ftrace_modify_all_code(int command)
2880{
2881 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2882 int mod_flags = 0;
2883 int err = 0;
2884
2885 if (command & FTRACE_MAY_SLEEP)
2886 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2887
2888 /*
2889 * If the ftrace_caller calls a ftrace_ops func directly,
2890 * we need to make sure that it only traces functions it
2891 * expects to trace. When doing the switch of functions,
2892 * we need to update to the ftrace_ops_list_func first
2893 * before the transition between old and new calls are set,
2894 * as the ftrace_ops_list_func will check the ops hashes
2895 * to make sure the ops are having the right functions
2896 * traced.
2897 */
2898 if (update) {
2899 err = update_ftrace_func(ftrace_ops_list_func);
2900 if (FTRACE_WARN_ON(err))
2901 return;
2902 }
2903
2904 if (command & FTRACE_UPDATE_CALLS)
2905 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2906 else if (command & FTRACE_DISABLE_CALLS)
2907 ftrace_replace_code(mod_flags);
2908
2909 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2910 function_trace_op = set_function_trace_op;
2911 smp_wmb();
2912 /* If irqs are disabled, we are in stop machine */
2913 if (!irqs_disabled())
2914 smp_call_function(ftrace_sync_ipi, NULL, 1);
2915 err = update_ftrace_func(ftrace_trace_function);
2916 if (FTRACE_WARN_ON(err))
2917 return;
2918 }
2919
2920 if (command & FTRACE_START_FUNC_RET)
2921 err = ftrace_enable_ftrace_graph_caller();
2922 else if (command & FTRACE_STOP_FUNC_RET)
2923 err = ftrace_disable_ftrace_graph_caller();
2924 FTRACE_WARN_ON(err);
2925}
2926
2927static int __ftrace_modify_code(void *data)
2928{
2929 int *command = data;
2930
2931 ftrace_modify_all_code(*command);
2932
2933 return 0;
2934}
2935
2936/**
2937 * ftrace_run_stop_machine - go back to the stop machine method
2938 * @command: The command to tell ftrace what to do
2939 *
2940 * If an arch needs to fall back to the stop machine method, the
2941 * it can call this function.
2942 */
2943void ftrace_run_stop_machine(int command)
2944{
2945 stop_machine(__ftrace_modify_code, &command, NULL);
2946}
2947
2948/**
2949 * arch_ftrace_update_code - modify the code to trace or not trace
2950 * @command: The command that needs to be done
2951 *
2952 * Archs can override this function if it does not need to
2953 * run stop_machine() to modify code.
2954 */
2955void __weak arch_ftrace_update_code(int command)
2956{
2957 ftrace_run_stop_machine(command);
2958}
2959
2960static void ftrace_run_update_code(int command)
2961{
2962 ftrace_arch_code_modify_prepare();
2963
2964 /*
2965 * By default we use stop_machine() to modify the code.
2966 * But archs can do what ever they want as long as it
2967 * is safe. The stop_machine() is the safest, but also
2968 * produces the most overhead.
2969 */
2970 arch_ftrace_update_code(command);
2971
2972 ftrace_arch_code_modify_post_process();
2973}
2974
2975static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2976 struct ftrace_ops_hash *old_hash)
2977{
2978 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2979 ops->old_hash.filter_hash = old_hash->filter_hash;
2980 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2981 ftrace_run_update_code(command);
2982 ops->old_hash.filter_hash = NULL;
2983 ops->old_hash.notrace_hash = NULL;
2984 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2985}
2986
2987static ftrace_func_t saved_ftrace_func;
2988static int ftrace_start_up;
2989
2990void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2991{
2992}
2993
2994/* List of trace_ops that have allocated trampolines */
2995static LIST_HEAD(ftrace_ops_trampoline_list);
2996
2997static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2998{
2999 lockdep_assert_held(&ftrace_lock);
3000 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
3001}
3002
3003static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
3004{
3005 lockdep_assert_held(&ftrace_lock);
3006 list_del_rcu(&ops->list);
3007 synchronize_rcu();
3008}
3009
3010/*
3011 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
3012 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
3013 * not a module.
3014 */
3015#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
3016#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
3017
3018static void ftrace_trampoline_free(struct ftrace_ops *ops)
3019{
3020 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
3021 ops->trampoline) {
3022 /*
3023 * Record the text poke event before the ksymbol unregister
3024 * event.
3025 */
3026 perf_event_text_poke((void *)ops->trampoline,
3027 (void *)ops->trampoline,
3028 ops->trampoline_size, NULL, 0);
3029 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
3030 ops->trampoline, ops->trampoline_size,
3031 true, FTRACE_TRAMPOLINE_SYM);
3032 /* Remove from kallsyms after the perf events */
3033 ftrace_remove_trampoline_from_kallsyms(ops);
3034 }
3035
3036 arch_ftrace_trampoline_free(ops);
3037}
3038
3039static void ftrace_startup_enable(int command)
3040{
3041 if (saved_ftrace_func != ftrace_trace_function) {
3042 saved_ftrace_func = ftrace_trace_function;
3043 command |= FTRACE_UPDATE_TRACE_FUNC;
3044 }
3045
3046 if (!command || !ftrace_enabled)
3047 return;
3048
3049 ftrace_run_update_code(command);
3050}
3051
3052static void ftrace_startup_all(int command)
3053{
3054 update_all_ops = true;
3055 ftrace_startup_enable(command);
3056 update_all_ops = false;
3057}
3058
3059int ftrace_startup(struct ftrace_ops *ops, int command)
3060{
3061 int ret;
3062
3063 if (unlikely(ftrace_disabled))
3064 return -ENODEV;
3065
3066 ret = __register_ftrace_function(ops);
3067 if (ret)
3068 return ret;
3069
3070 ftrace_start_up++;
3071
3072 /*
3073 * Note that ftrace probes uses this to start up
3074 * and modify functions it will probe. But we still
3075 * set the ADDING flag for modification, as probes
3076 * do not have trampolines. If they add them in the
3077 * future, then the probes will need to distinguish
3078 * between adding and updating probes.
3079 */
3080 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3081
3082 ret = ftrace_hash_ipmodify_enable(ops);
3083 if (ret < 0) {
3084 /* Rollback registration process */
3085 __unregister_ftrace_function(ops);
3086 ftrace_start_up--;
3087 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3088 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3089 ftrace_trampoline_free(ops);
3090 return ret;
3091 }
3092
3093 if (ftrace_hash_rec_enable(ops))
3094 command |= FTRACE_UPDATE_CALLS;
3095
3096 ftrace_startup_enable(command);
3097
3098 /*
3099 * If ftrace is in an undefined state, we just remove ops from list
3100 * to prevent the NULL pointer, instead of totally rolling it back and
3101 * free trampoline, because those actions could cause further damage.
3102 */
3103 if (unlikely(ftrace_disabled)) {
3104 __unregister_ftrace_function(ops);
3105 return -ENODEV;
3106 }
3107
3108 ops->flags &= ~FTRACE_OPS_FL_ADDING;
3109
3110 return 0;
3111}
3112
3113int ftrace_shutdown(struct ftrace_ops *ops, int command)
3114{
3115 int ret;
3116
3117 if (unlikely(ftrace_disabled))
3118 return -ENODEV;
3119
3120 ret = __unregister_ftrace_function(ops);
3121 if (ret)
3122 return ret;
3123
3124 ftrace_start_up--;
3125 /*
3126 * Just warn in case of unbalance, no need to kill ftrace, it's not
3127 * critical but the ftrace_call callers may be never nopped again after
3128 * further ftrace uses.
3129 */
3130 WARN_ON_ONCE(ftrace_start_up < 0);
3131
3132 /* Disabling ipmodify never fails */
3133 ftrace_hash_ipmodify_disable(ops);
3134
3135 if (ftrace_hash_rec_disable(ops))
3136 command |= FTRACE_UPDATE_CALLS;
3137
3138 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3139
3140 if (saved_ftrace_func != ftrace_trace_function) {
3141 saved_ftrace_func = ftrace_trace_function;
3142 command |= FTRACE_UPDATE_TRACE_FUNC;
3143 }
3144
3145 if (!command || !ftrace_enabled)
3146 goto out;
3147
3148 /*
3149 * If the ops uses a trampoline, then it needs to be
3150 * tested first on update.
3151 */
3152 ops->flags |= FTRACE_OPS_FL_REMOVING;
3153 removed_ops = ops;
3154
3155 /* The trampoline logic checks the old hashes */
3156 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3157 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3158
3159 ftrace_run_update_code(command);
3160
3161 /*
3162 * If there's no more ops registered with ftrace, run a
3163 * sanity check to make sure all rec flags are cleared.
3164 */
3165 if (rcu_dereference_protected(ftrace_ops_list,
3166 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3167 struct ftrace_page *pg;
3168 struct dyn_ftrace *rec;
3169
3170 do_for_each_ftrace_rec(pg, rec) {
3171 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3172 pr_warn(" %pS flags:%lx\n",
3173 (void *)rec->ip, rec->flags);
3174 } while_for_each_ftrace_rec();
3175 }
3176
3177 ops->old_hash.filter_hash = NULL;
3178 ops->old_hash.notrace_hash = NULL;
3179
3180 removed_ops = NULL;
3181 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3182
3183out:
3184 /*
3185 * Dynamic ops may be freed, we must make sure that all
3186 * callers are done before leaving this function.
3187 */
3188 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3189 /*
3190 * We need to do a hard force of sched synchronization.
3191 * This is because we use preempt_disable() to do RCU, but
3192 * the function tracers can be called where RCU is not watching
3193 * (like before user_exit()). We can not rely on the RCU
3194 * infrastructure to do the synchronization, thus we must do it
3195 * ourselves.
3196 */
3197 synchronize_rcu_tasks_rude();
3198
3199 /*
3200 * When the kernel is preemptive, tasks can be preempted
3201 * while on a ftrace trampoline. Just scheduling a task on
3202 * a CPU is not good enough to flush them. Calling
3203 * synchronize_rcu_tasks() will wait for those tasks to
3204 * execute and either schedule voluntarily or enter user space.
3205 */
3206 synchronize_rcu_tasks();
3207
3208 ftrace_trampoline_free(ops);
3209 }
3210
3211 return 0;
3212}
3213
3214/* Simply make a copy of @src and return it */
3215static struct ftrace_hash *copy_hash(struct ftrace_hash *src)
3216{
3217 if (ftrace_hash_empty(src))
3218 return EMPTY_HASH;
3219
3220 return alloc_and_copy_ftrace_hash(src->size_bits, src);
3221}
3222
3223/*
3224 * Append @new_hash entries to @hash:
3225 *
3226 * If @hash is the EMPTY_HASH then it traces all functions and nothing
3227 * needs to be done.
3228 *
3229 * If @new_hash is the EMPTY_HASH, then make *hash the EMPTY_HASH so
3230 * that it traces everything.
3231 *
3232 * Otherwise, go through all of @new_hash and add anything that @hash
3233 * doesn't already have, to @hash.
3234 *
3235 * The filter_hash updates uses just the append_hash() function
3236 * and the notrace_hash does not.
3237 */
3238static int append_hash(struct ftrace_hash **hash, struct ftrace_hash *new_hash,
3239 int size_bits)
3240{
3241 struct ftrace_func_entry *entry;
3242 int size;
3243 int i;
3244
3245 if (*hash) {
3246 /* An empty hash does everything */
3247 if (ftrace_hash_empty(*hash))
3248 return 0;
3249 } else {
3250 *hash = alloc_ftrace_hash(size_bits);
3251 if (!*hash)
3252 return -ENOMEM;
3253 }
3254
3255 /* If new_hash has everything make hash have everything */
3256 if (ftrace_hash_empty(new_hash)) {
3257 free_ftrace_hash(*hash);
3258 *hash = EMPTY_HASH;
3259 return 0;
3260 }
3261
3262 size = 1 << new_hash->size_bits;
3263 for (i = 0; i < size; i++) {
3264 hlist_for_each_entry(entry, &new_hash->buckets[i], hlist) {
3265 /* Only add if not already in hash */
3266 if (!__ftrace_lookup_ip(*hash, entry->ip) &&
3267 add_hash_entry(*hash, entry->ip) == NULL)
3268 return -ENOMEM;
3269 }
3270 }
3271 return 0;
3272}
3273
3274/*
3275 * Add to @hash only those that are in both @new_hash1 and @new_hash2
3276 *
3277 * The notrace_hash updates uses just the intersect_hash() function
3278 * and the filter_hash does not.
3279 */
3280static int intersect_hash(struct ftrace_hash **hash, struct ftrace_hash *new_hash1,
3281 struct ftrace_hash *new_hash2)
3282{
3283 struct ftrace_func_entry *entry;
3284 int size;
3285 int i;
3286
3287 /*
3288 * If new_hash1 or new_hash2 is the EMPTY_HASH then make the hash
3289 * empty as well as empty for notrace means none are notraced.
3290 */
3291 if (ftrace_hash_empty(new_hash1) || ftrace_hash_empty(new_hash2)) {
3292 free_ftrace_hash(*hash);
3293 *hash = EMPTY_HASH;
3294 return 0;
3295 }
3296
3297 size = 1 << new_hash1->size_bits;
3298 for (i = 0; i < size; i++) {
3299 hlist_for_each_entry(entry, &new_hash1->buckets[i], hlist) {
3300 /* Only add if in both @new_hash1 and @new_hash2 */
3301 if (__ftrace_lookup_ip(new_hash2, entry->ip) &&
3302 add_hash_entry(*hash, entry->ip) == NULL)
3303 return -ENOMEM;
3304 }
3305 }
3306 /* If nothing intersects, make it the empty set */
3307 if (ftrace_hash_empty(*hash)) {
3308 free_ftrace_hash(*hash);
3309 *hash = EMPTY_HASH;
3310 }
3311 return 0;
3312}
3313
3314/* Return a new hash that has a union of all @ops->filter_hash entries */
3315static struct ftrace_hash *append_hashes(struct ftrace_ops *ops)
3316{
3317 struct ftrace_hash *new_hash = NULL;
3318 struct ftrace_ops *subops;
3319 int size_bits;
3320 int ret;
3321
3322 if (ops->func_hash->filter_hash)
3323 size_bits = ops->func_hash->filter_hash->size_bits;
3324 else
3325 size_bits = FTRACE_HASH_DEFAULT_BITS;
3326
3327 list_for_each_entry(subops, &ops->subop_list, list) {
3328 ret = append_hash(&new_hash, subops->func_hash->filter_hash, size_bits);
3329 if (ret < 0) {
3330 free_ftrace_hash(new_hash);
3331 return NULL;
3332 }
3333 /* Nothing more to do if new_hash is empty */
3334 if (ftrace_hash_empty(new_hash))
3335 break;
3336 }
3337 /* Can't return NULL as that means this failed */
3338 return new_hash ? : EMPTY_HASH;
3339}
3340
3341/* Make @ops trace evenything except what all its subops do not trace */
3342static struct ftrace_hash *intersect_hashes(struct ftrace_ops *ops)
3343{
3344 struct ftrace_hash *new_hash = NULL;
3345 struct ftrace_ops *subops;
3346 int size_bits;
3347 int ret;
3348
3349 list_for_each_entry(subops, &ops->subop_list, list) {
3350 struct ftrace_hash *next_hash;
3351
3352 if (!new_hash) {
3353 size_bits = subops->func_hash->notrace_hash->size_bits;
3354 new_hash = alloc_and_copy_ftrace_hash(size_bits, ops->func_hash->notrace_hash);
3355 if (!new_hash)
3356 return NULL;
3357 continue;
3358 }
3359 size_bits = new_hash->size_bits;
3360 next_hash = new_hash;
3361 new_hash = alloc_ftrace_hash(size_bits);
3362 ret = intersect_hash(&new_hash, next_hash, subops->func_hash->notrace_hash);
3363 free_ftrace_hash(next_hash);
3364 if (ret < 0) {
3365 free_ftrace_hash(new_hash);
3366 return NULL;
3367 }
3368 /* Nothing more to do if new_hash is empty */
3369 if (ftrace_hash_empty(new_hash))
3370 break;
3371 }
3372 return new_hash;
3373}
3374
3375static bool ops_equal(struct ftrace_hash *A, struct ftrace_hash *B)
3376{
3377 struct ftrace_func_entry *entry;
3378 int size;
3379 int i;
3380
3381 if (ftrace_hash_empty(A))
3382 return ftrace_hash_empty(B);
3383
3384 if (ftrace_hash_empty(B))
3385 return ftrace_hash_empty(A);
3386
3387 if (A->count != B->count)
3388 return false;
3389
3390 size = 1 << A->size_bits;
3391 for (i = 0; i < size; i++) {
3392 hlist_for_each_entry(entry, &A->buckets[i], hlist) {
3393 if (!__ftrace_lookup_ip(B, entry->ip))
3394 return false;
3395 }
3396 }
3397
3398 return true;
3399}
3400
3401static void ftrace_ops_update_code(struct ftrace_ops *ops,
3402 struct ftrace_ops_hash *old_hash);
3403
3404static int __ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3405 struct ftrace_hash **orig_hash,
3406 struct ftrace_hash *hash,
3407 int enable)
3408{
3409 struct ftrace_ops_hash old_hash_ops;
3410 struct ftrace_hash *old_hash;
3411 int ret;
3412
3413 old_hash = *orig_hash;
3414 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3415 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3416 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3417 if (!ret) {
3418 ftrace_ops_update_code(ops, &old_hash_ops);
3419 free_ftrace_hash_rcu(old_hash);
3420 }
3421 return ret;
3422}
3423
3424static int ftrace_update_ops(struct ftrace_ops *ops, struct ftrace_hash *filter_hash,
3425 struct ftrace_hash *notrace_hash)
3426{
3427 int ret;
3428
3429 if (!ops_equal(filter_hash, ops->func_hash->filter_hash)) {
3430 ret = __ftrace_hash_move_and_update_ops(ops, &ops->func_hash->filter_hash,
3431 filter_hash, 1);
3432 if (ret < 0)
3433 return ret;
3434 }
3435
3436 if (!ops_equal(notrace_hash, ops->func_hash->notrace_hash)) {
3437 ret = __ftrace_hash_move_and_update_ops(ops, &ops->func_hash->notrace_hash,
3438 notrace_hash, 0);
3439 if (ret < 0)
3440 return ret;
3441 }
3442
3443 return 0;
3444}
3445
3446/**
3447 * ftrace_startup_subops - enable tracing for subops of an ops
3448 * @ops: Manager ops (used to pick all the functions of its subops)
3449 * @subops: A new ops to add to @ops
3450 * @command: Extra commands to use to enable tracing
3451 *
3452 * The @ops is a manager @ops that has the filter that includes all the functions
3453 * that its list of subops are tracing. Adding a new @subops will add the
3454 * functions of @subops to @ops.
3455 */
3456int ftrace_startup_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command)
3457{
3458 struct ftrace_hash *filter_hash;
3459 struct ftrace_hash *notrace_hash;
3460 struct ftrace_hash *save_filter_hash;
3461 struct ftrace_hash *save_notrace_hash;
3462 int size_bits;
3463 int ret;
3464
3465 if (unlikely(ftrace_disabled))
3466 return -ENODEV;
3467
3468 ftrace_ops_init(ops);
3469 ftrace_ops_init(subops);
3470
3471 if (WARN_ON_ONCE(subops->flags & FTRACE_OPS_FL_ENABLED))
3472 return -EBUSY;
3473
3474 /* Make everything canonical (Just in case!) */
3475 if (!ops->func_hash->filter_hash)
3476 ops->func_hash->filter_hash = EMPTY_HASH;
3477 if (!ops->func_hash->notrace_hash)
3478 ops->func_hash->notrace_hash = EMPTY_HASH;
3479 if (!subops->func_hash->filter_hash)
3480 subops->func_hash->filter_hash = EMPTY_HASH;
3481 if (!subops->func_hash->notrace_hash)
3482 subops->func_hash->notrace_hash = EMPTY_HASH;
3483
3484 /* For the first subops to ops just enable it normally */
3485 if (list_empty(&ops->subop_list)) {
3486 /* Just use the subops hashes */
3487 filter_hash = copy_hash(subops->func_hash->filter_hash);
3488 notrace_hash = copy_hash(subops->func_hash->notrace_hash);
3489 if (!filter_hash || !notrace_hash) {
3490 free_ftrace_hash(filter_hash);
3491 free_ftrace_hash(notrace_hash);
3492 return -ENOMEM;
3493 }
3494
3495 save_filter_hash = ops->func_hash->filter_hash;
3496 save_notrace_hash = ops->func_hash->notrace_hash;
3497
3498 ops->func_hash->filter_hash = filter_hash;
3499 ops->func_hash->notrace_hash = notrace_hash;
3500 list_add(&subops->list, &ops->subop_list);
3501 ret = ftrace_startup(ops, command);
3502 if (ret < 0) {
3503 list_del(&subops->list);
3504 ops->func_hash->filter_hash = save_filter_hash;
3505 ops->func_hash->notrace_hash = save_notrace_hash;
3506 free_ftrace_hash(filter_hash);
3507 free_ftrace_hash(notrace_hash);
3508 } else {
3509 free_ftrace_hash(save_filter_hash);
3510 free_ftrace_hash(save_notrace_hash);
3511 subops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP;
3512 subops->managed = ops;
3513 }
3514 return ret;
3515 }
3516
3517 /*
3518 * Here there's already something attached. Here are the rules:
3519 * o If either filter_hash is empty then the final stays empty
3520 * o Otherwise, the final is a superset of both hashes
3521 * o If either notrace_hash is empty then the final stays empty
3522 * o Otherwise, the final is an intersection between the hashes
3523 */
3524 if (ftrace_hash_empty(ops->func_hash->filter_hash) ||
3525 ftrace_hash_empty(subops->func_hash->filter_hash)) {
3526 filter_hash = EMPTY_HASH;
3527 } else {
3528 size_bits = max(ops->func_hash->filter_hash->size_bits,
3529 subops->func_hash->filter_hash->size_bits);
3530 filter_hash = alloc_and_copy_ftrace_hash(size_bits, ops->func_hash->filter_hash);
3531 if (!filter_hash)
3532 return -ENOMEM;
3533 ret = append_hash(&filter_hash, subops->func_hash->filter_hash,
3534 size_bits);
3535 if (ret < 0) {
3536 free_ftrace_hash(filter_hash);
3537 return ret;
3538 }
3539 }
3540
3541 if (ftrace_hash_empty(ops->func_hash->notrace_hash) ||
3542 ftrace_hash_empty(subops->func_hash->notrace_hash)) {
3543 notrace_hash = EMPTY_HASH;
3544 } else {
3545 size_bits = max(ops->func_hash->filter_hash->size_bits,
3546 subops->func_hash->filter_hash->size_bits);
3547 notrace_hash = alloc_ftrace_hash(size_bits);
3548 if (!notrace_hash) {
3549 free_ftrace_hash(filter_hash);
3550 return -ENOMEM;
3551 }
3552
3553 ret = intersect_hash(¬race_hash, ops->func_hash->filter_hash,
3554 subops->func_hash->filter_hash);
3555 if (ret < 0) {
3556 free_ftrace_hash(filter_hash);
3557 free_ftrace_hash(notrace_hash);
3558 return ret;
3559 }
3560 }
3561
3562 list_add(&subops->list, &ops->subop_list);
3563
3564 ret = ftrace_update_ops(ops, filter_hash, notrace_hash);
3565 free_ftrace_hash(filter_hash);
3566 free_ftrace_hash(notrace_hash);
3567 if (ret < 0) {
3568 list_del(&subops->list);
3569 } else {
3570 subops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP;
3571 subops->managed = ops;
3572 }
3573 return ret;
3574}
3575
3576/**
3577 * ftrace_shutdown_subops - Remove a subops from a manager ops
3578 * @ops: A manager ops to remove @subops from
3579 * @subops: The subops to remove from @ops
3580 * @command: Any extra command flags to add to modifying the text
3581 *
3582 * Removes the functions being traced by the @subops from @ops. Note, it
3583 * will not affect functions that are being traced by other subops that
3584 * still exist in @ops.
3585 *
3586 * If the last subops is removed from @ops, then @ops is shutdown normally.
3587 */
3588int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command)
3589{
3590 struct ftrace_hash *filter_hash;
3591 struct ftrace_hash *notrace_hash;
3592 int ret;
3593
3594 if (unlikely(ftrace_disabled))
3595 return -ENODEV;
3596
3597 if (WARN_ON_ONCE(!(subops->flags & FTRACE_OPS_FL_ENABLED)))
3598 return -EINVAL;
3599
3600 list_del(&subops->list);
3601
3602 if (list_empty(&ops->subop_list)) {
3603 /* Last one, just disable the current ops */
3604
3605 ret = ftrace_shutdown(ops, command);
3606 if (ret < 0) {
3607 list_add(&subops->list, &ops->subop_list);
3608 return ret;
3609 }
3610
3611 subops->flags &= ~FTRACE_OPS_FL_ENABLED;
3612
3613 free_ftrace_hash(ops->func_hash->filter_hash);
3614 free_ftrace_hash(ops->func_hash->notrace_hash);
3615 ops->func_hash->filter_hash = EMPTY_HASH;
3616 ops->func_hash->notrace_hash = EMPTY_HASH;
3617 subops->flags &= ~(FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP);
3618 subops->managed = NULL;
3619
3620 return 0;
3621 }
3622
3623 /* Rebuild the hashes without subops */
3624 filter_hash = append_hashes(ops);
3625 notrace_hash = intersect_hashes(ops);
3626 if (!filter_hash || !notrace_hash) {
3627 free_ftrace_hash(filter_hash);
3628 free_ftrace_hash(notrace_hash);
3629 list_add(&subops->list, &ops->subop_list);
3630 return -ENOMEM;
3631 }
3632
3633 ret = ftrace_update_ops(ops, filter_hash, notrace_hash);
3634 if (ret < 0) {
3635 list_add(&subops->list, &ops->subop_list);
3636 } else {
3637 subops->flags &= ~(FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP);
3638 subops->managed = NULL;
3639 }
3640 free_ftrace_hash(filter_hash);
3641 free_ftrace_hash(notrace_hash);
3642 return ret;
3643}
3644
3645static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops,
3646 struct ftrace_hash **orig_subhash,
3647 struct ftrace_hash *hash,
3648 int enable)
3649{
3650 struct ftrace_ops *ops = subops->managed;
3651 struct ftrace_hash **orig_hash;
3652 struct ftrace_hash *save_hash;
3653 struct ftrace_hash *new_hash;
3654 int ret;
3655
3656 /* Manager ops can not be subops (yet) */
3657 if (WARN_ON_ONCE(!ops || ops->flags & FTRACE_OPS_FL_SUBOP))
3658 return -EINVAL;
3659
3660 /* Move the new hash over to the subops hash */
3661 save_hash = *orig_subhash;
3662 *orig_subhash = __ftrace_hash_move(hash);
3663 if (!*orig_subhash) {
3664 *orig_subhash = save_hash;
3665 return -ENOMEM;
3666 }
3667
3668 /* Create a new_hash to hold the ops new functions */
3669 if (enable) {
3670 orig_hash = &ops->func_hash->filter_hash;
3671 new_hash = append_hashes(ops);
3672 } else {
3673 orig_hash = &ops->func_hash->notrace_hash;
3674 new_hash = intersect_hashes(ops);
3675 }
3676
3677 /* Move the hash over to the new hash */
3678 ret = __ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable);
3679
3680 free_ftrace_hash(new_hash);
3681
3682 if (ret) {
3683 /* Put back the original hash */
3684 free_ftrace_hash_rcu(*orig_subhash);
3685 *orig_subhash = save_hash;
3686 } else {
3687 free_ftrace_hash_rcu(save_hash);
3688 }
3689 return ret;
3690}
3691
3692
3693u64 ftrace_update_time;
3694u64 ftrace_total_mod_time;
3695unsigned long ftrace_update_tot_cnt;
3696unsigned long ftrace_number_of_pages;
3697unsigned long ftrace_number_of_groups;
3698
3699static inline int ops_traces_mod(struct ftrace_ops *ops)
3700{
3701 /*
3702 * Filter_hash being empty will default to trace module.
3703 * But notrace hash requires a test of individual module functions.
3704 */
3705 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3706 ftrace_hash_empty(ops->func_hash->notrace_hash);
3707}
3708
3709static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3710{
3711 bool init_nop = ftrace_need_init_nop();
3712 struct ftrace_page *pg;
3713 struct dyn_ftrace *p;
3714 u64 start, stop, update_time;
3715 unsigned long update_cnt = 0;
3716 unsigned long rec_flags = 0;
3717 int i;
3718
3719 start = ftrace_now(raw_smp_processor_id());
3720
3721 /*
3722 * When a module is loaded, this function is called to convert
3723 * the calls to mcount in its text to nops, and also to create
3724 * an entry in the ftrace data. Now, if ftrace is activated
3725 * after this call, but before the module sets its text to
3726 * read-only, the modification of enabling ftrace can fail if
3727 * the read-only is done while ftrace is converting the calls.
3728 * To prevent this, the module's records are set as disabled
3729 * and will be enabled after the call to set the module's text
3730 * to read-only.
3731 */
3732 if (mod)
3733 rec_flags |= FTRACE_FL_DISABLED;
3734
3735 for (pg = new_pgs; pg; pg = pg->next) {
3736
3737 for (i = 0; i < pg->index; i++) {
3738
3739 /* If something went wrong, bail without enabling anything */
3740 if (unlikely(ftrace_disabled))
3741 return -1;
3742
3743 p = &pg->records[i];
3744 p->flags = rec_flags;
3745
3746 /*
3747 * Do the initial record conversion from mcount jump
3748 * to the NOP instructions.
3749 */
3750 if (init_nop && !ftrace_nop_initialize(mod, p))
3751 break;
3752
3753 update_cnt++;
3754 }
3755 }
3756
3757 stop = ftrace_now(raw_smp_processor_id());
3758 update_time = stop - start;
3759 if (mod)
3760 ftrace_total_mod_time += update_time;
3761 else
3762 ftrace_update_time = update_time;
3763 ftrace_update_tot_cnt += update_cnt;
3764
3765 return 0;
3766}
3767
3768static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3769{
3770 int order;
3771 int pages;
3772 int cnt;
3773
3774 if (WARN_ON(!count))
3775 return -EINVAL;
3776
3777 /* We want to fill as much as possible, with no empty pages */
3778 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3779 order = fls(pages) - 1;
3780
3781 again:
3782 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3783
3784 if (!pg->records) {
3785 /* if we can't allocate this size, try something smaller */
3786 if (!order)
3787 return -ENOMEM;
3788 order--;
3789 goto again;
3790 }
3791
3792 ftrace_number_of_pages += 1 << order;
3793 ftrace_number_of_groups++;
3794
3795 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3796 pg->order = order;
3797
3798 if (cnt > count)
3799 cnt = count;
3800
3801 return cnt;
3802}
3803
3804static void ftrace_free_pages(struct ftrace_page *pages)
3805{
3806 struct ftrace_page *pg = pages;
3807
3808 while (pg) {
3809 if (pg->records) {
3810 free_pages((unsigned long)pg->records, pg->order);
3811 ftrace_number_of_pages -= 1 << pg->order;
3812 }
3813 pages = pg->next;
3814 kfree(pg);
3815 pg = pages;
3816 ftrace_number_of_groups--;
3817 }
3818}
3819
3820static struct ftrace_page *
3821ftrace_allocate_pages(unsigned long num_to_init)
3822{
3823 struct ftrace_page *start_pg;
3824 struct ftrace_page *pg;
3825 int cnt;
3826
3827 if (!num_to_init)
3828 return NULL;
3829
3830 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3831 if (!pg)
3832 return NULL;
3833
3834 /*
3835 * Try to allocate as much as possible in one continues
3836 * location that fills in all of the space. We want to
3837 * waste as little space as possible.
3838 */
3839 for (;;) {
3840 cnt = ftrace_allocate_records(pg, num_to_init);
3841 if (cnt < 0)
3842 goto free_pages;
3843
3844 num_to_init -= cnt;
3845 if (!num_to_init)
3846 break;
3847
3848 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3849 if (!pg->next)
3850 goto free_pages;
3851
3852 pg = pg->next;
3853 }
3854
3855 return start_pg;
3856
3857 free_pages:
3858 ftrace_free_pages(start_pg);
3859 pr_info("ftrace: FAILED to allocate memory for functions\n");
3860 return NULL;
3861}
3862
3863#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3864
3865struct ftrace_iterator {
3866 loff_t pos;
3867 loff_t func_pos;
3868 loff_t mod_pos;
3869 struct ftrace_page *pg;
3870 struct dyn_ftrace *func;
3871 struct ftrace_func_probe *probe;
3872 struct ftrace_func_entry *probe_entry;
3873 struct trace_parser parser;
3874 struct ftrace_hash *hash;
3875 struct ftrace_ops *ops;
3876 struct trace_array *tr;
3877 struct list_head *mod_list;
3878 int pidx;
3879 int idx;
3880 unsigned flags;
3881};
3882
3883static void *
3884t_probe_next(struct seq_file *m, loff_t *pos)
3885{
3886 struct ftrace_iterator *iter = m->private;
3887 struct trace_array *tr = iter->ops->private;
3888 struct list_head *func_probes;
3889 struct ftrace_hash *hash;
3890 struct list_head *next;
3891 struct hlist_node *hnd = NULL;
3892 struct hlist_head *hhd;
3893 int size;
3894
3895 (*pos)++;
3896 iter->pos = *pos;
3897
3898 if (!tr)
3899 return NULL;
3900
3901 func_probes = &tr->func_probes;
3902 if (list_empty(func_probes))
3903 return NULL;
3904
3905 if (!iter->probe) {
3906 next = func_probes->next;
3907 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3908 }
3909
3910 if (iter->probe_entry)
3911 hnd = &iter->probe_entry->hlist;
3912
3913 hash = iter->probe->ops.func_hash->filter_hash;
3914
3915 /*
3916 * A probe being registered may temporarily have an empty hash
3917 * and it's at the end of the func_probes list.
3918 */
3919 if (!hash || hash == EMPTY_HASH)
3920 return NULL;
3921
3922 size = 1 << hash->size_bits;
3923
3924 retry:
3925 if (iter->pidx >= size) {
3926 if (iter->probe->list.next == func_probes)
3927 return NULL;
3928 next = iter->probe->list.next;
3929 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3930 hash = iter->probe->ops.func_hash->filter_hash;
3931 size = 1 << hash->size_bits;
3932 iter->pidx = 0;
3933 }
3934
3935 hhd = &hash->buckets[iter->pidx];
3936
3937 if (hlist_empty(hhd)) {
3938 iter->pidx++;
3939 hnd = NULL;
3940 goto retry;
3941 }
3942
3943 if (!hnd)
3944 hnd = hhd->first;
3945 else {
3946 hnd = hnd->next;
3947 if (!hnd) {
3948 iter->pidx++;
3949 goto retry;
3950 }
3951 }
3952
3953 if (WARN_ON_ONCE(!hnd))
3954 return NULL;
3955
3956 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3957
3958 return iter;
3959}
3960
3961static void *t_probe_start(struct seq_file *m, loff_t *pos)
3962{
3963 struct ftrace_iterator *iter = m->private;
3964 void *p = NULL;
3965 loff_t l;
3966
3967 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3968 return NULL;
3969
3970 if (iter->mod_pos > *pos)
3971 return NULL;
3972
3973 iter->probe = NULL;
3974 iter->probe_entry = NULL;
3975 iter->pidx = 0;
3976 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3977 p = t_probe_next(m, &l);
3978 if (!p)
3979 break;
3980 }
3981 if (!p)
3982 return NULL;
3983
3984 /* Only set this if we have an item */
3985 iter->flags |= FTRACE_ITER_PROBE;
3986
3987 return iter;
3988}
3989
3990static int
3991t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3992{
3993 struct ftrace_func_entry *probe_entry;
3994 struct ftrace_probe_ops *probe_ops;
3995 struct ftrace_func_probe *probe;
3996
3997 probe = iter->probe;
3998 probe_entry = iter->probe_entry;
3999
4000 if (WARN_ON_ONCE(!probe || !probe_entry))
4001 return -EIO;
4002
4003 probe_ops = probe->probe_ops;
4004
4005 if (probe_ops->print)
4006 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
4007
4008 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
4009 (void *)probe_ops->func);
4010
4011 return 0;
4012}
4013
4014static void *
4015t_mod_next(struct seq_file *m, loff_t *pos)
4016{
4017 struct ftrace_iterator *iter = m->private;
4018 struct trace_array *tr = iter->tr;
4019
4020 (*pos)++;
4021 iter->pos = *pos;
4022
4023 iter->mod_list = iter->mod_list->next;
4024
4025 if (iter->mod_list == &tr->mod_trace ||
4026 iter->mod_list == &tr->mod_notrace) {
4027 iter->flags &= ~FTRACE_ITER_MOD;
4028 return NULL;
4029 }
4030
4031 iter->mod_pos = *pos;
4032
4033 return iter;
4034}
4035
4036static void *t_mod_start(struct seq_file *m, loff_t *pos)
4037{
4038 struct ftrace_iterator *iter = m->private;
4039 void *p = NULL;
4040 loff_t l;
4041
4042 if (iter->func_pos > *pos)
4043 return NULL;
4044
4045 iter->mod_pos = iter->func_pos;
4046
4047 /* probes are only available if tr is set */
4048 if (!iter->tr)
4049 return NULL;
4050
4051 for (l = 0; l <= (*pos - iter->func_pos); ) {
4052 p = t_mod_next(m, &l);
4053 if (!p)
4054 break;
4055 }
4056 if (!p) {
4057 iter->flags &= ~FTRACE_ITER_MOD;
4058 return t_probe_start(m, pos);
4059 }
4060
4061 /* Only set this if we have an item */
4062 iter->flags |= FTRACE_ITER_MOD;
4063
4064 return iter;
4065}
4066
4067static int
4068t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
4069{
4070 struct ftrace_mod_load *ftrace_mod;
4071 struct trace_array *tr = iter->tr;
4072
4073 if (WARN_ON_ONCE(!iter->mod_list) ||
4074 iter->mod_list == &tr->mod_trace ||
4075 iter->mod_list == &tr->mod_notrace)
4076 return -EIO;
4077
4078 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
4079
4080 if (ftrace_mod->func)
4081 seq_printf(m, "%s", ftrace_mod->func);
4082 else
4083 seq_putc(m, '*');
4084
4085 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
4086
4087 return 0;
4088}
4089
4090static void *
4091t_func_next(struct seq_file *m, loff_t *pos)
4092{
4093 struct ftrace_iterator *iter = m->private;
4094 struct dyn_ftrace *rec = NULL;
4095
4096 (*pos)++;
4097
4098 retry:
4099 if (iter->idx >= iter->pg->index) {
4100 if (iter->pg->next) {
4101 iter->pg = iter->pg->next;
4102 iter->idx = 0;
4103 goto retry;
4104 }
4105 } else {
4106 rec = &iter->pg->records[iter->idx++];
4107 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
4108 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
4109
4110 ((iter->flags & FTRACE_ITER_ENABLED) &&
4111 !(rec->flags & FTRACE_FL_ENABLED)) ||
4112
4113 ((iter->flags & FTRACE_ITER_TOUCHED) &&
4114 !(rec->flags & FTRACE_FL_TOUCHED))) {
4115
4116 rec = NULL;
4117 goto retry;
4118 }
4119 }
4120
4121 if (!rec)
4122 return NULL;
4123
4124 iter->pos = iter->func_pos = *pos;
4125 iter->func = rec;
4126
4127 return iter;
4128}
4129
4130static void *
4131t_next(struct seq_file *m, void *v, loff_t *pos)
4132{
4133 struct ftrace_iterator *iter = m->private;
4134 loff_t l = *pos; /* t_probe_start() must use original pos */
4135 void *ret;
4136
4137 if (unlikely(ftrace_disabled))
4138 return NULL;
4139
4140 if (iter->flags & FTRACE_ITER_PROBE)
4141 return t_probe_next(m, pos);
4142
4143 if (iter->flags & FTRACE_ITER_MOD)
4144 return t_mod_next(m, pos);
4145
4146 if (iter->flags & FTRACE_ITER_PRINTALL) {
4147 /* next must increment pos, and t_probe_start does not */
4148 (*pos)++;
4149 return t_mod_start(m, &l);
4150 }
4151
4152 ret = t_func_next(m, pos);
4153
4154 if (!ret)
4155 return t_mod_start(m, &l);
4156
4157 return ret;
4158}
4159
4160static void reset_iter_read(struct ftrace_iterator *iter)
4161{
4162 iter->pos = 0;
4163 iter->func_pos = 0;
4164 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
4165}
4166
4167static void *t_start(struct seq_file *m, loff_t *pos)
4168{
4169 struct ftrace_iterator *iter = m->private;
4170 void *p = NULL;
4171 loff_t l;
4172
4173 mutex_lock(&ftrace_lock);
4174
4175 if (unlikely(ftrace_disabled))
4176 return NULL;
4177
4178 /*
4179 * If an lseek was done, then reset and start from beginning.
4180 */
4181 if (*pos < iter->pos)
4182 reset_iter_read(iter);
4183
4184 /*
4185 * For set_ftrace_filter reading, if we have the filter
4186 * off, we can short cut and just print out that all
4187 * functions are enabled.
4188 */
4189 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
4190 ftrace_hash_empty(iter->hash)) {
4191 iter->func_pos = 1; /* Account for the message */
4192 if (*pos > 0)
4193 return t_mod_start(m, pos);
4194 iter->flags |= FTRACE_ITER_PRINTALL;
4195 /* reset in case of seek/pread */
4196 iter->flags &= ~FTRACE_ITER_PROBE;
4197 return iter;
4198 }
4199
4200 if (iter->flags & FTRACE_ITER_MOD)
4201 return t_mod_start(m, pos);
4202
4203 /*
4204 * Unfortunately, we need to restart at ftrace_pages_start
4205 * every time we let go of the ftrace_mutex. This is because
4206 * those pointers can change without the lock.
4207 */
4208 iter->pg = ftrace_pages_start;
4209 iter->idx = 0;
4210 for (l = 0; l <= *pos; ) {
4211 p = t_func_next(m, &l);
4212 if (!p)
4213 break;
4214 }
4215
4216 if (!p)
4217 return t_mod_start(m, pos);
4218
4219 return iter;
4220}
4221
4222static void t_stop(struct seq_file *m, void *p)
4223{
4224 mutex_unlock(&ftrace_lock);
4225}
4226
4227void * __weak
4228arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
4229{
4230 return NULL;
4231}
4232
4233static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
4234 struct dyn_ftrace *rec)
4235{
4236 void *ptr;
4237
4238 ptr = arch_ftrace_trampoline_func(ops, rec);
4239 if (ptr)
4240 seq_printf(m, " ->%pS", ptr);
4241}
4242
4243#ifdef FTRACE_MCOUNT_MAX_OFFSET
4244/*
4245 * Weak functions can still have an mcount/fentry that is saved in
4246 * the __mcount_loc section. These can be detected by having a
4247 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
4248 * symbol found by kallsyms is not the function that the mcount/fentry
4249 * is part of. The offset is much greater in these cases.
4250 *
4251 * Test the record to make sure that the ip points to a valid kallsyms
4252 * and if not, mark it disabled.
4253 */
4254static int test_for_valid_rec(struct dyn_ftrace *rec)
4255{
4256 char str[KSYM_SYMBOL_LEN];
4257 unsigned long offset;
4258 const char *ret;
4259
4260 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
4261
4262 /* Weak functions can cause invalid addresses */
4263 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
4264 rec->flags |= FTRACE_FL_DISABLED;
4265 return 0;
4266 }
4267 return 1;
4268}
4269
4270static struct workqueue_struct *ftrace_check_wq __initdata;
4271static struct work_struct ftrace_check_work __initdata;
4272
4273/*
4274 * Scan all the mcount/fentry entries to make sure they are valid.
4275 */
4276static __init void ftrace_check_work_func(struct work_struct *work)
4277{
4278 struct ftrace_page *pg;
4279 struct dyn_ftrace *rec;
4280
4281 mutex_lock(&ftrace_lock);
4282 do_for_each_ftrace_rec(pg, rec) {
4283 test_for_valid_rec(rec);
4284 } while_for_each_ftrace_rec();
4285 mutex_unlock(&ftrace_lock);
4286}
4287
4288static int __init ftrace_check_for_weak_functions(void)
4289{
4290 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
4291
4292 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
4293
4294 queue_work(ftrace_check_wq, &ftrace_check_work);
4295 return 0;
4296}
4297
4298static int __init ftrace_check_sync(void)
4299{
4300 /* Make sure the ftrace_check updates are finished */
4301 if (ftrace_check_wq)
4302 destroy_workqueue(ftrace_check_wq);
4303 return 0;
4304}
4305
4306late_initcall_sync(ftrace_check_sync);
4307subsys_initcall(ftrace_check_for_weak_functions);
4308
4309static int print_rec(struct seq_file *m, unsigned long ip)
4310{
4311 unsigned long offset;
4312 char str[KSYM_SYMBOL_LEN];
4313 char *modname;
4314 const char *ret;
4315
4316 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
4317 /* Weak functions can cause invalid addresses */
4318 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
4319 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
4320 FTRACE_INVALID_FUNCTION, offset);
4321 ret = NULL;
4322 }
4323
4324 seq_puts(m, str);
4325 if (modname)
4326 seq_printf(m, " [%s]", modname);
4327 return ret == NULL ? -1 : 0;
4328}
4329#else
4330static inline int test_for_valid_rec(struct dyn_ftrace *rec)
4331{
4332 return 1;
4333}
4334
4335static inline int print_rec(struct seq_file *m, unsigned long ip)
4336{
4337 seq_printf(m, "%ps", (void *)ip);
4338 return 0;
4339}
4340#endif
4341
4342static int t_show(struct seq_file *m, void *v)
4343{
4344 struct ftrace_iterator *iter = m->private;
4345 struct dyn_ftrace *rec;
4346
4347 if (iter->flags & FTRACE_ITER_PROBE)
4348 return t_probe_show(m, iter);
4349
4350 if (iter->flags & FTRACE_ITER_MOD)
4351 return t_mod_show(m, iter);
4352
4353 if (iter->flags & FTRACE_ITER_PRINTALL) {
4354 if (iter->flags & FTRACE_ITER_NOTRACE)
4355 seq_puts(m, "#### no functions disabled ####\n");
4356 else
4357 seq_puts(m, "#### all functions enabled ####\n");
4358 return 0;
4359 }
4360
4361 rec = iter->func;
4362
4363 if (!rec)
4364 return 0;
4365
4366 if (iter->flags & FTRACE_ITER_ADDRS)
4367 seq_printf(m, "%lx ", rec->ip);
4368
4369 if (print_rec(m, rec->ip)) {
4370 /* This should only happen when a rec is disabled */
4371 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
4372 seq_putc(m, '\n');
4373 return 0;
4374 }
4375
4376 if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
4377 struct ftrace_ops *ops;
4378
4379 seq_printf(m, " (%ld)%s%s%s%s%s",
4380 ftrace_rec_count(rec),
4381 rec->flags & FTRACE_FL_REGS ? " R" : " ",
4382 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
4383 rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
4384 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
4385 rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
4386 if (rec->flags & FTRACE_FL_TRAMP_EN) {
4387 ops = ftrace_find_tramp_ops_any(rec);
4388 if (ops) {
4389 do {
4390 seq_printf(m, "\ttramp: %pS (%pS)",
4391 (void *)ops->trampoline,
4392 (void *)ops->func);
4393 add_trampoline_func(m, ops, rec);
4394 ops = ftrace_find_tramp_ops_next(rec, ops);
4395 } while (ops);
4396 } else
4397 seq_puts(m, "\ttramp: ERROR!");
4398 } else {
4399 add_trampoline_func(m, NULL, rec);
4400 }
4401 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
4402 ops = ftrace_find_unique_ops(rec);
4403 if (ops) {
4404 seq_printf(m, "\tops: %pS (%pS)",
4405 ops, ops->func);
4406 } else {
4407 seq_puts(m, "\tops: ERROR!");
4408 }
4409 }
4410 if (rec->flags & FTRACE_FL_DIRECT) {
4411 unsigned long direct;
4412
4413 direct = ftrace_find_rec_direct(rec->ip);
4414 if (direct)
4415 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
4416 }
4417 }
4418
4419 seq_putc(m, '\n');
4420
4421 return 0;
4422}
4423
4424static const struct seq_operations show_ftrace_seq_ops = {
4425 .start = t_start,
4426 .next = t_next,
4427 .stop = t_stop,
4428 .show = t_show,
4429};
4430
4431static int
4432ftrace_avail_open(struct inode *inode, struct file *file)
4433{
4434 struct ftrace_iterator *iter;
4435 int ret;
4436
4437 ret = security_locked_down(LOCKDOWN_TRACEFS);
4438 if (ret)
4439 return ret;
4440
4441 if (unlikely(ftrace_disabled))
4442 return -ENODEV;
4443
4444 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
4445 if (!iter)
4446 return -ENOMEM;
4447
4448 iter->pg = ftrace_pages_start;
4449 iter->ops = &global_ops;
4450
4451 return 0;
4452}
4453
4454static int
4455ftrace_enabled_open(struct inode *inode, struct file *file)
4456{
4457 struct ftrace_iterator *iter;
4458
4459 /*
4460 * This shows us what functions are currently being
4461 * traced and by what. Not sure if we want lockdown
4462 * to hide such critical information for an admin.
4463 * Although, perhaps it can show information we don't
4464 * want people to see, but if something is tracing
4465 * something, we probably want to know about it.
4466 */
4467
4468 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
4469 if (!iter)
4470 return -ENOMEM;
4471
4472 iter->pg = ftrace_pages_start;
4473 iter->flags = FTRACE_ITER_ENABLED;
4474 iter->ops = &global_ops;
4475
4476 return 0;
4477}
4478
4479static int
4480ftrace_touched_open(struct inode *inode, struct file *file)
4481{
4482 struct ftrace_iterator *iter;
4483
4484 /*
4485 * This shows us what functions have ever been enabled
4486 * (traced, direct, patched, etc). Not sure if we want lockdown
4487 * to hide such critical information for an admin.
4488 * Although, perhaps it can show information we don't
4489 * want people to see, but if something had traced
4490 * something, we probably want to know about it.
4491 */
4492
4493 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
4494 if (!iter)
4495 return -ENOMEM;
4496
4497 iter->pg = ftrace_pages_start;
4498 iter->flags = FTRACE_ITER_TOUCHED;
4499 iter->ops = &global_ops;
4500
4501 return 0;
4502}
4503
4504static int
4505ftrace_avail_addrs_open(struct inode *inode, struct file *file)
4506{
4507 struct ftrace_iterator *iter;
4508 int ret;
4509
4510 ret = security_locked_down(LOCKDOWN_TRACEFS);
4511 if (ret)
4512 return ret;
4513
4514 if (unlikely(ftrace_disabled))
4515 return -ENODEV;
4516
4517 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
4518 if (!iter)
4519 return -ENOMEM;
4520
4521 iter->pg = ftrace_pages_start;
4522 iter->flags = FTRACE_ITER_ADDRS;
4523 iter->ops = &global_ops;
4524
4525 return 0;
4526}
4527
4528/**
4529 * ftrace_regex_open - initialize function tracer filter files
4530 * @ops: The ftrace_ops that hold the hash filters
4531 * @flag: The type of filter to process
4532 * @inode: The inode, usually passed in to your open routine
4533 * @file: The file, usually passed in to your open routine
4534 *
4535 * ftrace_regex_open() initializes the filter files for the
4536 * @ops. Depending on @flag it may process the filter hash or
4537 * the notrace hash of @ops. With this called from the open
4538 * routine, you can use ftrace_filter_write() for the write
4539 * routine if @flag has FTRACE_ITER_FILTER set, or
4540 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4541 * tracing_lseek() should be used as the lseek routine, and
4542 * release must call ftrace_regex_release().
4543 *
4544 * Returns: 0 on success or a negative errno value on failure
4545 */
4546int
4547ftrace_regex_open(struct ftrace_ops *ops, int flag,
4548 struct inode *inode, struct file *file)
4549{
4550 struct ftrace_iterator *iter;
4551 struct ftrace_hash *hash;
4552 struct list_head *mod_head;
4553 struct trace_array *tr = ops->private;
4554 int ret = -ENOMEM;
4555
4556 ftrace_ops_init(ops);
4557
4558 if (unlikely(ftrace_disabled))
4559 return -ENODEV;
4560
4561 if (tracing_check_open_get_tr(tr))
4562 return -ENODEV;
4563
4564 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4565 if (!iter)
4566 goto out;
4567
4568 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4569 goto out;
4570
4571 iter->ops = ops;
4572 iter->flags = flag;
4573 iter->tr = tr;
4574
4575 mutex_lock(&ops->func_hash->regex_lock);
4576
4577 if (flag & FTRACE_ITER_NOTRACE) {
4578 hash = ops->func_hash->notrace_hash;
4579 mod_head = tr ? &tr->mod_notrace : NULL;
4580 } else {
4581 hash = ops->func_hash->filter_hash;
4582 mod_head = tr ? &tr->mod_trace : NULL;
4583 }
4584
4585 iter->mod_list = mod_head;
4586
4587 if (file->f_mode & FMODE_WRITE) {
4588 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4589
4590 if (file->f_flags & O_TRUNC) {
4591 iter->hash = alloc_ftrace_hash(size_bits);
4592 clear_ftrace_mod_list(mod_head);
4593 } else {
4594 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4595 }
4596
4597 if (!iter->hash) {
4598 trace_parser_put(&iter->parser);
4599 goto out_unlock;
4600 }
4601 } else
4602 iter->hash = hash;
4603
4604 ret = 0;
4605
4606 if (file->f_mode & FMODE_READ) {
4607 iter->pg = ftrace_pages_start;
4608
4609 ret = seq_open(file, &show_ftrace_seq_ops);
4610 if (!ret) {
4611 struct seq_file *m = file->private_data;
4612 m->private = iter;
4613 } else {
4614 /* Failed */
4615 free_ftrace_hash(iter->hash);
4616 trace_parser_put(&iter->parser);
4617 }
4618 } else
4619 file->private_data = iter;
4620
4621 out_unlock:
4622 mutex_unlock(&ops->func_hash->regex_lock);
4623
4624 out:
4625 if (ret) {
4626 kfree(iter);
4627 if (tr)
4628 trace_array_put(tr);
4629 }
4630
4631 return ret;
4632}
4633
4634static int
4635ftrace_filter_open(struct inode *inode, struct file *file)
4636{
4637 struct ftrace_ops *ops = inode->i_private;
4638
4639 /* Checks for tracefs lockdown */
4640 return ftrace_regex_open(ops,
4641 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4642 inode, file);
4643}
4644
4645static int
4646ftrace_notrace_open(struct inode *inode, struct file *file)
4647{
4648 struct ftrace_ops *ops = inode->i_private;
4649
4650 /* Checks for tracefs lockdown */
4651 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4652 inode, file);
4653}
4654
4655/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4656struct ftrace_glob {
4657 char *search;
4658 unsigned len;
4659 int type;
4660};
4661
4662/*
4663 * If symbols in an architecture don't correspond exactly to the user-visible
4664 * name of what they represent, it is possible to define this function to
4665 * perform the necessary adjustments.
4666*/
4667char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4668{
4669 return str;
4670}
4671
4672static int ftrace_match(char *str, struct ftrace_glob *g)
4673{
4674 int matched = 0;
4675 int slen;
4676
4677 str = arch_ftrace_match_adjust(str, g->search);
4678
4679 switch (g->type) {
4680 case MATCH_FULL:
4681 if (strcmp(str, g->search) == 0)
4682 matched = 1;
4683 break;
4684 case MATCH_FRONT_ONLY:
4685 if (strncmp(str, g->search, g->len) == 0)
4686 matched = 1;
4687 break;
4688 case MATCH_MIDDLE_ONLY:
4689 if (strstr(str, g->search))
4690 matched = 1;
4691 break;
4692 case MATCH_END_ONLY:
4693 slen = strlen(str);
4694 if (slen >= g->len &&
4695 memcmp(str + slen - g->len, g->search, g->len) == 0)
4696 matched = 1;
4697 break;
4698 case MATCH_GLOB:
4699 if (glob_match(g->search, str))
4700 matched = 1;
4701 break;
4702 }
4703
4704 return matched;
4705}
4706
4707static int
4708enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4709{
4710 struct ftrace_func_entry *entry;
4711 int ret = 0;
4712
4713 entry = ftrace_lookup_ip(hash, rec->ip);
4714 if (clear_filter) {
4715 /* Do nothing if it doesn't exist */
4716 if (!entry)
4717 return 0;
4718
4719 free_hash_entry(hash, entry);
4720 } else {
4721 /* Do nothing if it exists */
4722 if (entry)
4723 return 0;
4724 if (add_hash_entry(hash, rec->ip) == NULL)
4725 ret = -ENOMEM;
4726 }
4727 return ret;
4728}
4729
4730static int
4731add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4732 int clear_filter)
4733{
4734 long index;
4735 struct ftrace_page *pg;
4736 struct dyn_ftrace *rec;
4737
4738 /* The index starts at 1 */
4739 if (kstrtoul(func_g->search, 0, &index) || --index < 0)
4740 return 0;
4741
4742 do_for_each_ftrace_rec(pg, rec) {
4743 if (pg->index <= index) {
4744 index -= pg->index;
4745 /* this is a double loop, break goes to the next page */
4746 break;
4747 }
4748 rec = &pg->records[index];
4749 enter_record(hash, rec, clear_filter);
4750 return 1;
4751 } while_for_each_ftrace_rec();
4752 return 0;
4753}
4754
4755#ifdef FTRACE_MCOUNT_MAX_OFFSET
4756static int lookup_ip(unsigned long ip, char **modname, char *str)
4757{
4758 unsigned long offset;
4759
4760 kallsyms_lookup(ip, NULL, &offset, modname, str);
4761 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4762 return -1;
4763 return 0;
4764}
4765#else
4766static int lookup_ip(unsigned long ip, char **modname, char *str)
4767{
4768 kallsyms_lookup(ip, NULL, NULL, modname, str);
4769 return 0;
4770}
4771#endif
4772
4773static int
4774ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4775 struct ftrace_glob *mod_g, int exclude_mod)
4776{
4777 char str[KSYM_SYMBOL_LEN];
4778 char *modname;
4779
4780 if (lookup_ip(rec->ip, &modname, str)) {
4781 /* This should only happen when a rec is disabled */
4782 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4783 !(rec->flags & FTRACE_FL_DISABLED));
4784 return 0;
4785 }
4786
4787 if (mod_g) {
4788 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4789
4790 /* blank module name to match all modules */
4791 if (!mod_g->len) {
4792 /* blank module globbing: modname xor exclude_mod */
4793 if (!exclude_mod != !modname)
4794 goto func_match;
4795 return 0;
4796 }
4797
4798 /*
4799 * exclude_mod is set to trace everything but the given
4800 * module. If it is set and the module matches, then
4801 * return 0. If it is not set, and the module doesn't match
4802 * also return 0. Otherwise, check the function to see if
4803 * that matches.
4804 */
4805 if (!mod_matches == !exclude_mod)
4806 return 0;
4807func_match:
4808 /* blank search means to match all funcs in the mod */
4809 if (!func_g->len)
4810 return 1;
4811 }
4812
4813 return ftrace_match(str, func_g);
4814}
4815
4816static int
4817match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4818{
4819 struct ftrace_page *pg;
4820 struct dyn_ftrace *rec;
4821 struct ftrace_glob func_g = { .type = MATCH_FULL };
4822 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4823 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4824 int exclude_mod = 0;
4825 int found = 0;
4826 int ret;
4827 int clear_filter = 0;
4828
4829 if (func) {
4830 func_g.type = filter_parse_regex(func, len, &func_g.search,
4831 &clear_filter);
4832 func_g.len = strlen(func_g.search);
4833 }
4834
4835 if (mod) {
4836 mod_g.type = filter_parse_regex(mod, strlen(mod),
4837 &mod_g.search, &exclude_mod);
4838 mod_g.len = strlen(mod_g.search);
4839 }
4840
4841 guard(mutex)(&ftrace_lock);
4842
4843 if (unlikely(ftrace_disabled))
4844 return 0;
4845
4846 if (func_g.type == MATCH_INDEX)
4847 return add_rec_by_index(hash, &func_g, clear_filter);
4848
4849 do_for_each_ftrace_rec(pg, rec) {
4850
4851 if (rec->flags & FTRACE_FL_DISABLED)
4852 continue;
4853
4854 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4855 ret = enter_record(hash, rec, clear_filter);
4856 if (ret < 0)
4857 return ret;
4858 found = 1;
4859 }
4860 cond_resched();
4861 } while_for_each_ftrace_rec();
4862
4863 return found;
4864}
4865
4866static int
4867ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4868{
4869 return match_records(hash, buff, len, NULL);
4870}
4871
4872static void ftrace_ops_update_code(struct ftrace_ops *ops,
4873 struct ftrace_ops_hash *old_hash)
4874{
4875 struct ftrace_ops *op;
4876
4877 if (!ftrace_enabled)
4878 return;
4879
4880 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4881 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4882 return;
4883 }
4884
4885 /*
4886 * If this is the shared global_ops filter, then we need to
4887 * check if there is another ops that shares it, is enabled.
4888 * If so, we still need to run the modify code.
4889 */
4890 if (ops->func_hash != &global_ops.local_hash)
4891 return;
4892
4893 do_for_each_ftrace_op(op, ftrace_ops_list) {
4894 if (op->func_hash == &global_ops.local_hash &&
4895 op->flags & FTRACE_OPS_FL_ENABLED) {
4896 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4897 /* Only need to do this once */
4898 return;
4899 }
4900 } while_for_each_ftrace_op(op);
4901}
4902
4903static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4904 struct ftrace_hash **orig_hash,
4905 struct ftrace_hash *hash,
4906 int enable)
4907{
4908 if (ops->flags & FTRACE_OPS_FL_SUBOP)
4909 return ftrace_hash_move_and_update_subops(ops, orig_hash, hash, enable);
4910
4911 /*
4912 * If this ops is not enabled, it could be sharing its filters
4913 * with a subop. If that's the case, update the subop instead of
4914 * this ops. Shared filters are only allowed to have one ops set
4915 * at a time, and if we update the ops that is not enabled,
4916 * it will not affect subops that share it.
4917 */
4918 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) {
4919 struct ftrace_ops *op;
4920
4921 /* Check if any other manager subops maps to this hash */
4922 do_for_each_ftrace_op(op, ftrace_ops_list) {
4923 struct ftrace_ops *subops;
4924
4925 list_for_each_entry(subops, &op->subop_list, list) {
4926 if ((subops->flags & FTRACE_OPS_FL_ENABLED) &&
4927 subops->func_hash == ops->func_hash) {
4928 return ftrace_hash_move_and_update_subops(subops, orig_hash, hash, enable);
4929 }
4930 }
4931 } while_for_each_ftrace_op(op);
4932 }
4933
4934 return __ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4935}
4936
4937static bool module_exists(const char *module)
4938{
4939 /* All modules have the symbol __this_module */
4940 static const char this_mod[] = "__this_module";
4941 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4942 unsigned long val;
4943 int n;
4944
4945 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4946
4947 if (n > sizeof(modname) - 1)
4948 return false;
4949
4950 val = module_kallsyms_lookup_name(modname);
4951 return val != 0;
4952}
4953
4954static int cache_mod(struct trace_array *tr,
4955 const char *func, char *module, int enable)
4956{
4957 struct ftrace_mod_load *ftrace_mod, *n;
4958 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4959
4960 guard(mutex)(&ftrace_lock);
4961
4962 /* We do not cache inverse filters */
4963 if (func[0] == '!') {
4964 int ret = -EINVAL;
4965
4966 func++;
4967
4968 /* Look to remove this hash */
4969 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4970 if (strcmp(ftrace_mod->module, module) != 0)
4971 continue;
4972
4973 /* no func matches all */
4974 if (strcmp(func, "*") == 0 ||
4975 (ftrace_mod->func &&
4976 strcmp(ftrace_mod->func, func) == 0)) {
4977 ret = 0;
4978 free_ftrace_mod(ftrace_mod);
4979 continue;
4980 }
4981 }
4982 return ret;
4983 }
4984
4985 /* We only care about modules that have not been loaded yet */
4986 if (module_exists(module))
4987 return -EINVAL;
4988
4989 /* Save this string off, and execute it when the module is loaded */
4990 return ftrace_add_mod(tr, func, module, enable);
4991}
4992
4993static int
4994ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4995 int reset, int enable);
4996
4997#ifdef CONFIG_MODULES
4998static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4999 char *mod, bool enable)
5000{
5001 struct ftrace_mod_load *ftrace_mod, *n;
5002 struct ftrace_hash **orig_hash, *new_hash;
5003 LIST_HEAD(process_mods);
5004 char *func;
5005
5006 mutex_lock(&ops->func_hash->regex_lock);
5007
5008 if (enable)
5009 orig_hash = &ops->func_hash->filter_hash;
5010 else
5011 orig_hash = &ops->func_hash->notrace_hash;
5012
5013 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
5014 *orig_hash);
5015 if (!new_hash)
5016 goto out; /* warn? */
5017
5018 mutex_lock(&ftrace_lock);
5019
5020 list_for_each_entry_safe(ftrace_mod, n, head, list) {
5021
5022 if (strcmp(ftrace_mod->module, mod) != 0)
5023 continue;
5024
5025 if (ftrace_mod->func)
5026 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
5027 else
5028 func = kstrdup("*", GFP_KERNEL);
5029
5030 if (!func) /* warn? */
5031 continue;
5032
5033 list_move(&ftrace_mod->list, &process_mods);
5034
5035 /* Use the newly allocated func, as it may be "*" */
5036 kfree(ftrace_mod->func);
5037 ftrace_mod->func = func;
5038 }
5039
5040 mutex_unlock(&ftrace_lock);
5041
5042 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
5043
5044 func = ftrace_mod->func;
5045
5046 /* Grabs ftrace_lock, which is why we have this extra step */
5047 match_records(new_hash, func, strlen(func), mod);
5048 free_ftrace_mod(ftrace_mod);
5049 }
5050
5051 if (enable && list_empty(head))
5052 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
5053
5054 mutex_lock(&ftrace_lock);
5055
5056 ftrace_hash_move_and_update_ops(ops, orig_hash,
5057 new_hash, enable);
5058 mutex_unlock(&ftrace_lock);
5059
5060 out:
5061 mutex_unlock(&ops->func_hash->regex_lock);
5062
5063 free_ftrace_hash(new_hash);
5064}
5065
5066static void process_cached_mods(const char *mod_name)
5067{
5068 struct trace_array *tr;
5069 char *mod;
5070
5071 mod = kstrdup(mod_name, GFP_KERNEL);
5072 if (!mod)
5073 return;
5074
5075 mutex_lock(&trace_types_lock);
5076 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5077 if (!list_empty(&tr->mod_trace))
5078 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
5079 if (!list_empty(&tr->mod_notrace))
5080 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
5081 }
5082 mutex_unlock(&trace_types_lock);
5083
5084 kfree(mod);
5085}
5086#endif
5087
5088/*
5089 * We register the module command as a template to show others how
5090 * to register the a command as well.
5091 */
5092
5093static int
5094ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
5095 char *func_orig, char *cmd, char *module, int enable)
5096{
5097 char *func;
5098 int ret;
5099
5100 if (!tr)
5101 return -ENODEV;
5102
5103 /* match_records() modifies func, and we need the original */
5104 func = kstrdup(func_orig, GFP_KERNEL);
5105 if (!func)
5106 return -ENOMEM;
5107
5108 /*
5109 * cmd == 'mod' because we only registered this func
5110 * for the 'mod' ftrace_func_command.
5111 * But if you register one func with multiple commands,
5112 * you can tell which command was used by the cmd
5113 * parameter.
5114 */
5115 ret = match_records(hash, func, strlen(func), module);
5116 kfree(func);
5117
5118 if (!ret)
5119 return cache_mod(tr, func_orig, module, enable);
5120 if (ret < 0)
5121 return ret;
5122 return 0;
5123}
5124
5125static struct ftrace_func_command ftrace_mod_cmd = {
5126 .name = "mod",
5127 .func = ftrace_mod_callback,
5128};
5129
5130static int __init ftrace_mod_cmd_init(void)
5131{
5132 return register_ftrace_command(&ftrace_mod_cmd);
5133}
5134core_initcall(ftrace_mod_cmd_init);
5135
5136static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
5137 struct ftrace_ops *op, struct ftrace_regs *fregs)
5138{
5139 struct ftrace_probe_ops *probe_ops;
5140 struct ftrace_func_probe *probe;
5141
5142 probe = container_of(op, struct ftrace_func_probe, ops);
5143 probe_ops = probe->probe_ops;
5144
5145 /*
5146 * Disable preemption for these calls to prevent a RCU grace
5147 * period. This syncs the hash iteration and freeing of items
5148 * on the hash. rcu_read_lock is too dangerous here.
5149 */
5150 preempt_disable_notrace();
5151 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
5152 preempt_enable_notrace();
5153}
5154
5155struct ftrace_func_map {
5156 struct ftrace_func_entry entry;
5157 void *data;
5158};
5159
5160struct ftrace_func_mapper {
5161 struct ftrace_hash hash;
5162};
5163
5164/**
5165 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
5166 *
5167 * Returns: a ftrace_func_mapper descriptor that can be used to map ips to data.
5168 */
5169struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
5170{
5171 struct ftrace_hash *hash;
5172
5173 /*
5174 * The mapper is simply a ftrace_hash, but since the entries
5175 * in the hash are not ftrace_func_entry type, we define it
5176 * as a separate structure.
5177 */
5178 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5179 return (struct ftrace_func_mapper *)hash;
5180}
5181
5182/**
5183 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
5184 * @mapper: The mapper that has the ip maps
5185 * @ip: the instruction pointer to find the data for
5186 *
5187 * Returns: the data mapped to @ip if found otherwise NULL. The return
5188 * is actually the address of the mapper data pointer. The address is
5189 * returned for use cases where the data is no bigger than a long, and
5190 * the user can use the data pointer as its data instead of having to
5191 * allocate more memory for the reference.
5192 */
5193void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
5194 unsigned long ip)
5195{
5196 struct ftrace_func_entry *entry;
5197 struct ftrace_func_map *map;
5198
5199 entry = ftrace_lookup_ip(&mapper->hash, ip);
5200 if (!entry)
5201 return NULL;
5202
5203 map = (struct ftrace_func_map *)entry;
5204 return &map->data;
5205}
5206
5207/**
5208 * ftrace_func_mapper_add_ip - Map some data to an ip
5209 * @mapper: The mapper that has the ip maps
5210 * @ip: The instruction pointer address to map @data to
5211 * @data: The data to map to @ip
5212 *
5213 * Returns: 0 on success otherwise an error.
5214 */
5215int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
5216 unsigned long ip, void *data)
5217{
5218 struct ftrace_func_entry *entry;
5219 struct ftrace_func_map *map;
5220
5221 entry = ftrace_lookup_ip(&mapper->hash, ip);
5222 if (entry)
5223 return -EBUSY;
5224
5225 map = kmalloc(sizeof(*map), GFP_KERNEL);
5226 if (!map)
5227 return -ENOMEM;
5228
5229 map->entry.ip = ip;
5230 map->data = data;
5231
5232 __add_hash_entry(&mapper->hash, &map->entry);
5233
5234 return 0;
5235}
5236
5237/**
5238 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
5239 * @mapper: The mapper that has the ip maps
5240 * @ip: The instruction pointer address to remove the data from
5241 *
5242 * Returns: the data if it is found, otherwise NULL.
5243 * Note, if the data pointer is used as the data itself, (see
5244 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
5245 * if the data pointer was set to zero.
5246 */
5247void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
5248 unsigned long ip)
5249{
5250 struct ftrace_func_entry *entry;
5251 struct ftrace_func_map *map;
5252 void *data;
5253
5254 entry = ftrace_lookup_ip(&mapper->hash, ip);
5255 if (!entry)
5256 return NULL;
5257
5258 map = (struct ftrace_func_map *)entry;
5259 data = map->data;
5260
5261 remove_hash_entry(&mapper->hash, entry);
5262 kfree(entry);
5263
5264 return data;
5265}
5266
5267/**
5268 * free_ftrace_func_mapper - free a mapping of ips and data
5269 * @mapper: The mapper that has the ip maps
5270 * @free_func: A function to be called on each data item.
5271 *
5272 * This is used to free the function mapper. The @free_func is optional
5273 * and can be used if the data needs to be freed as well.
5274 */
5275void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
5276 ftrace_mapper_func free_func)
5277{
5278 struct ftrace_func_entry *entry;
5279 struct ftrace_func_map *map;
5280 struct hlist_head *hhd;
5281 int size, i;
5282
5283 if (!mapper)
5284 return;
5285
5286 if (free_func && mapper->hash.count) {
5287 size = 1 << mapper->hash.size_bits;
5288 for (i = 0; i < size; i++) {
5289 hhd = &mapper->hash.buckets[i];
5290 hlist_for_each_entry(entry, hhd, hlist) {
5291 map = (struct ftrace_func_map *)entry;
5292 free_func(map);
5293 }
5294 }
5295 }
5296 free_ftrace_hash(&mapper->hash);
5297}
5298
5299static void release_probe(struct ftrace_func_probe *probe)
5300{
5301 struct ftrace_probe_ops *probe_ops;
5302
5303 guard(mutex)(&ftrace_lock);
5304
5305 WARN_ON(probe->ref <= 0);
5306
5307 /* Subtract the ref that was used to protect this instance */
5308 probe->ref--;
5309
5310 if (!probe->ref) {
5311 probe_ops = probe->probe_ops;
5312 /*
5313 * Sending zero as ip tells probe_ops to free
5314 * the probe->data itself
5315 */
5316 if (probe_ops->free)
5317 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
5318 list_del(&probe->list);
5319 kfree(probe);
5320 }
5321}
5322
5323static void acquire_probe_locked(struct ftrace_func_probe *probe)
5324{
5325 /*
5326 * Add one ref to keep it from being freed when releasing the
5327 * ftrace_lock mutex.
5328 */
5329 probe->ref++;
5330}
5331
5332int
5333register_ftrace_function_probe(char *glob, struct trace_array *tr,
5334 struct ftrace_probe_ops *probe_ops,
5335 void *data)
5336{
5337 struct ftrace_func_probe *probe = NULL, *iter;
5338 struct ftrace_func_entry *entry;
5339 struct ftrace_hash **orig_hash;
5340 struct ftrace_hash *old_hash;
5341 struct ftrace_hash *hash;
5342 int count = 0;
5343 int size;
5344 int ret;
5345 int i;
5346
5347 if (WARN_ON(!tr))
5348 return -EINVAL;
5349
5350 /* We do not support '!' for function probes */
5351 if (WARN_ON(glob[0] == '!'))
5352 return -EINVAL;
5353
5354
5355 mutex_lock(&ftrace_lock);
5356 /* Check if the probe_ops is already registered */
5357 list_for_each_entry(iter, &tr->func_probes, list) {
5358 if (iter->probe_ops == probe_ops) {
5359 probe = iter;
5360 break;
5361 }
5362 }
5363 if (!probe) {
5364 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
5365 if (!probe) {
5366 mutex_unlock(&ftrace_lock);
5367 return -ENOMEM;
5368 }
5369 probe->probe_ops = probe_ops;
5370 probe->ops.func = function_trace_probe_call;
5371 probe->tr = tr;
5372 ftrace_ops_init(&probe->ops);
5373 list_add(&probe->list, &tr->func_probes);
5374 }
5375
5376 acquire_probe_locked(probe);
5377
5378 mutex_unlock(&ftrace_lock);
5379
5380 /*
5381 * Note, there's a small window here that the func_hash->filter_hash
5382 * may be NULL or empty. Need to be careful when reading the loop.
5383 */
5384 mutex_lock(&probe->ops.func_hash->regex_lock);
5385
5386 orig_hash = &probe->ops.func_hash->filter_hash;
5387 old_hash = *orig_hash;
5388 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5389
5390 if (!hash) {
5391 ret = -ENOMEM;
5392 goto out;
5393 }
5394
5395 ret = ftrace_match_records(hash, glob, strlen(glob));
5396
5397 /* Nothing found? */
5398 if (!ret)
5399 ret = -EINVAL;
5400
5401 if (ret < 0)
5402 goto out;
5403
5404 size = 1 << hash->size_bits;
5405 for (i = 0; i < size; i++) {
5406 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5407 if (ftrace_lookup_ip(old_hash, entry->ip))
5408 continue;
5409 /*
5410 * The caller might want to do something special
5411 * for each function we find. We call the callback
5412 * to give the caller an opportunity to do so.
5413 */
5414 if (probe_ops->init) {
5415 ret = probe_ops->init(probe_ops, tr,
5416 entry->ip, data,
5417 &probe->data);
5418 if (ret < 0) {
5419 if (probe_ops->free && count)
5420 probe_ops->free(probe_ops, tr,
5421 0, probe->data);
5422 probe->data = NULL;
5423 goto out;
5424 }
5425 }
5426 count++;
5427 }
5428 }
5429
5430 mutex_lock(&ftrace_lock);
5431
5432 if (!count) {
5433 /* Nothing was added? */
5434 ret = -EINVAL;
5435 goto out_unlock;
5436 }
5437
5438 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5439 hash, 1);
5440 if (ret < 0)
5441 goto err_unlock;
5442
5443 /* One ref for each new function traced */
5444 probe->ref += count;
5445
5446 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
5447 ret = ftrace_startup(&probe->ops, 0);
5448
5449 out_unlock:
5450 mutex_unlock(&ftrace_lock);
5451
5452 if (!ret)
5453 ret = count;
5454 out:
5455 mutex_unlock(&probe->ops.func_hash->regex_lock);
5456 free_ftrace_hash(hash);
5457
5458 release_probe(probe);
5459
5460 return ret;
5461
5462 err_unlock:
5463 if (!probe_ops->free || !count)
5464 goto out_unlock;
5465
5466 /* Failed to do the move, need to call the free functions */
5467 for (i = 0; i < size; i++) {
5468 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5469 if (ftrace_lookup_ip(old_hash, entry->ip))
5470 continue;
5471 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5472 }
5473 }
5474 goto out_unlock;
5475}
5476
5477int
5478unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
5479 struct ftrace_probe_ops *probe_ops)
5480{
5481 struct ftrace_func_probe *probe = NULL, *iter;
5482 struct ftrace_ops_hash old_hash_ops;
5483 struct ftrace_func_entry *entry;
5484 struct ftrace_glob func_g;
5485 struct ftrace_hash **orig_hash;
5486 struct ftrace_hash *old_hash;
5487 struct ftrace_hash *hash = NULL;
5488 struct hlist_node *tmp;
5489 struct hlist_head hhd;
5490 char str[KSYM_SYMBOL_LEN];
5491 int count = 0;
5492 int i, ret = -ENODEV;
5493 int size;
5494
5495 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
5496 func_g.search = NULL;
5497 else {
5498 int not;
5499
5500 func_g.type = filter_parse_regex(glob, strlen(glob),
5501 &func_g.search, ¬);
5502 func_g.len = strlen(func_g.search);
5503
5504 /* we do not support '!' for function probes */
5505 if (WARN_ON(not))
5506 return -EINVAL;
5507 }
5508
5509 mutex_lock(&ftrace_lock);
5510 /* Check if the probe_ops is already registered */
5511 list_for_each_entry(iter, &tr->func_probes, list) {
5512 if (iter->probe_ops == probe_ops) {
5513 probe = iter;
5514 break;
5515 }
5516 }
5517 if (!probe)
5518 goto err_unlock_ftrace;
5519
5520 ret = -EINVAL;
5521 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
5522 goto err_unlock_ftrace;
5523
5524 acquire_probe_locked(probe);
5525
5526 mutex_unlock(&ftrace_lock);
5527
5528 mutex_lock(&probe->ops.func_hash->regex_lock);
5529
5530 orig_hash = &probe->ops.func_hash->filter_hash;
5531 old_hash = *orig_hash;
5532
5533 if (ftrace_hash_empty(old_hash))
5534 goto out_unlock;
5535
5536 old_hash_ops.filter_hash = old_hash;
5537 /* Probes only have filters */
5538 old_hash_ops.notrace_hash = NULL;
5539
5540 ret = -ENOMEM;
5541 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5542 if (!hash)
5543 goto out_unlock;
5544
5545 INIT_HLIST_HEAD(&hhd);
5546
5547 size = 1 << hash->size_bits;
5548 for (i = 0; i < size; i++) {
5549 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5550
5551 if (func_g.search) {
5552 kallsyms_lookup(entry->ip, NULL, NULL,
5553 NULL, str);
5554 if (!ftrace_match(str, &func_g))
5555 continue;
5556 }
5557 count++;
5558 remove_hash_entry(hash, entry);
5559 hlist_add_head(&entry->hlist, &hhd);
5560 }
5561 }
5562
5563 /* Nothing found? */
5564 if (!count) {
5565 ret = -EINVAL;
5566 goto out_unlock;
5567 }
5568
5569 mutex_lock(&ftrace_lock);
5570
5571 WARN_ON(probe->ref < count);
5572
5573 probe->ref -= count;
5574
5575 if (ftrace_hash_empty(hash))
5576 ftrace_shutdown(&probe->ops, 0);
5577
5578 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5579 hash, 1);
5580
5581 /* still need to update the function call sites */
5582 if (ftrace_enabled && !ftrace_hash_empty(hash))
5583 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5584 &old_hash_ops);
5585 synchronize_rcu();
5586
5587 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5588 hlist_del(&entry->hlist);
5589 if (probe_ops->free)
5590 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5591 kfree(entry);
5592 }
5593 mutex_unlock(&ftrace_lock);
5594
5595 out_unlock:
5596 mutex_unlock(&probe->ops.func_hash->regex_lock);
5597 free_ftrace_hash(hash);
5598
5599 release_probe(probe);
5600
5601 return ret;
5602
5603 err_unlock_ftrace:
5604 mutex_unlock(&ftrace_lock);
5605 return ret;
5606}
5607
5608void clear_ftrace_function_probes(struct trace_array *tr)
5609{
5610 struct ftrace_func_probe *probe, *n;
5611
5612 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5613 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5614}
5615
5616static LIST_HEAD(ftrace_commands);
5617static DEFINE_MUTEX(ftrace_cmd_mutex);
5618
5619/*
5620 * Currently we only register ftrace commands from __init, so mark this
5621 * __init too.
5622 */
5623__init int register_ftrace_command(struct ftrace_func_command *cmd)
5624{
5625 struct ftrace_func_command *p;
5626 int ret = 0;
5627
5628 mutex_lock(&ftrace_cmd_mutex);
5629 list_for_each_entry(p, &ftrace_commands, list) {
5630 if (strcmp(cmd->name, p->name) == 0) {
5631 ret = -EBUSY;
5632 goto out_unlock;
5633 }
5634 }
5635 list_add(&cmd->list, &ftrace_commands);
5636 out_unlock:
5637 mutex_unlock(&ftrace_cmd_mutex);
5638
5639 return ret;
5640}
5641
5642/*
5643 * Currently we only unregister ftrace commands from __init, so mark
5644 * this __init too.
5645 */
5646__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5647{
5648 struct ftrace_func_command *p, *n;
5649 int ret = -ENODEV;
5650
5651 mutex_lock(&ftrace_cmd_mutex);
5652 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5653 if (strcmp(cmd->name, p->name) == 0) {
5654 ret = 0;
5655 list_del_init(&p->list);
5656 goto out_unlock;
5657 }
5658 }
5659 out_unlock:
5660 mutex_unlock(&ftrace_cmd_mutex);
5661
5662 return ret;
5663}
5664
5665static int ftrace_process_regex(struct ftrace_iterator *iter,
5666 char *buff, int len, int enable)
5667{
5668 struct ftrace_hash *hash = iter->hash;
5669 struct trace_array *tr = iter->ops->private;
5670 char *func, *command, *next = buff;
5671 struct ftrace_func_command *p;
5672 int ret = -EINVAL;
5673
5674 func = strsep(&next, ":");
5675
5676 if (!next) {
5677 ret = ftrace_match_records(hash, func, len);
5678 if (!ret)
5679 ret = -EINVAL;
5680 if (ret < 0)
5681 return ret;
5682 return 0;
5683 }
5684
5685 /* command found */
5686
5687 command = strsep(&next, ":");
5688
5689 mutex_lock(&ftrace_cmd_mutex);
5690 list_for_each_entry(p, &ftrace_commands, list) {
5691 if (strcmp(p->name, command) == 0) {
5692 ret = p->func(tr, hash, func, command, next, enable);
5693 goto out_unlock;
5694 }
5695 }
5696 out_unlock:
5697 mutex_unlock(&ftrace_cmd_mutex);
5698
5699 return ret;
5700}
5701
5702static ssize_t
5703ftrace_regex_write(struct file *file, const char __user *ubuf,
5704 size_t cnt, loff_t *ppos, int enable)
5705{
5706 struct ftrace_iterator *iter;
5707 struct trace_parser *parser;
5708 ssize_t ret, read;
5709
5710 if (!cnt)
5711 return 0;
5712
5713 if (file->f_mode & FMODE_READ) {
5714 struct seq_file *m = file->private_data;
5715 iter = m->private;
5716 } else
5717 iter = file->private_data;
5718
5719 if (unlikely(ftrace_disabled))
5720 return -ENODEV;
5721
5722 /* iter->hash is a local copy, so we don't need regex_lock */
5723
5724 parser = &iter->parser;
5725 read = trace_get_user(parser, ubuf, cnt, ppos);
5726
5727 if (read >= 0 && trace_parser_loaded(parser) &&
5728 !trace_parser_cont(parser)) {
5729 ret = ftrace_process_regex(iter, parser->buffer,
5730 parser->idx, enable);
5731 trace_parser_clear(parser);
5732 if (ret < 0)
5733 goto out;
5734 }
5735
5736 ret = read;
5737 out:
5738 return ret;
5739}
5740
5741ssize_t
5742ftrace_filter_write(struct file *file, const char __user *ubuf,
5743 size_t cnt, loff_t *ppos)
5744{
5745 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5746}
5747
5748ssize_t
5749ftrace_notrace_write(struct file *file, const char __user *ubuf,
5750 size_t cnt, loff_t *ppos)
5751{
5752 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5753}
5754
5755static int
5756__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5757{
5758 struct ftrace_func_entry *entry;
5759
5760 ip = ftrace_location(ip);
5761 if (!ip)
5762 return -EINVAL;
5763
5764 if (remove) {
5765 entry = ftrace_lookup_ip(hash, ip);
5766 if (!entry)
5767 return -ENOENT;
5768 free_hash_entry(hash, entry);
5769 return 0;
5770 } else if (__ftrace_lookup_ip(hash, ip) != NULL) {
5771 /* Already exists */
5772 return 0;
5773 }
5774
5775 entry = add_hash_entry(hash, ip);
5776 return entry ? 0 : -ENOMEM;
5777}
5778
5779static int
5780ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5781 unsigned int cnt, int remove)
5782{
5783 unsigned int i;
5784 int err;
5785
5786 for (i = 0; i < cnt; i++) {
5787 err = __ftrace_match_addr(hash, ips[i], remove);
5788 if (err) {
5789 /*
5790 * This expects the @hash is a temporary hash and if this
5791 * fails the caller must free the @hash.
5792 */
5793 return err;
5794 }
5795 }
5796 return 0;
5797}
5798
5799static int
5800ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5801 unsigned long *ips, unsigned int cnt,
5802 int remove, int reset, int enable)
5803{
5804 struct ftrace_hash **orig_hash;
5805 struct ftrace_hash *hash;
5806 int ret;
5807
5808 if (unlikely(ftrace_disabled))
5809 return -ENODEV;
5810
5811 mutex_lock(&ops->func_hash->regex_lock);
5812
5813 if (enable)
5814 orig_hash = &ops->func_hash->filter_hash;
5815 else
5816 orig_hash = &ops->func_hash->notrace_hash;
5817
5818 if (reset)
5819 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5820 else
5821 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5822
5823 if (!hash) {
5824 ret = -ENOMEM;
5825 goto out_regex_unlock;
5826 }
5827
5828 if (buf && !ftrace_match_records(hash, buf, len)) {
5829 ret = -EINVAL;
5830 goto out_regex_unlock;
5831 }
5832 if (ips) {
5833 ret = ftrace_match_addr(hash, ips, cnt, remove);
5834 if (ret < 0)
5835 goto out_regex_unlock;
5836 }
5837
5838 mutex_lock(&ftrace_lock);
5839 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5840 mutex_unlock(&ftrace_lock);
5841
5842 out_regex_unlock:
5843 mutex_unlock(&ops->func_hash->regex_lock);
5844
5845 free_ftrace_hash(hash);
5846 return ret;
5847}
5848
5849static int
5850ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5851 int remove, int reset, int enable)
5852{
5853 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5854}
5855
5856#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5857
5858static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5859
5860/*
5861 * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
5862 * call will be jumped from ftrace_regs_caller. Only if the architecture does
5863 * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
5864 * jumps from ftrace_caller for multiple ftrace_ops.
5865 */
5866#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
5867#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5868#else
5869#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5870#endif
5871
5872static int check_direct_multi(struct ftrace_ops *ops)
5873{
5874 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5875 return -EINVAL;
5876 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5877 return -EINVAL;
5878 return 0;
5879}
5880
5881static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5882{
5883 struct ftrace_func_entry *entry, *del;
5884 int size, i;
5885
5886 size = 1 << hash->size_bits;
5887 for (i = 0; i < size; i++) {
5888 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5889 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5890 if (del && del->direct == addr) {
5891 remove_hash_entry(direct_functions, del);
5892 kfree(del);
5893 }
5894 }
5895 }
5896}
5897
5898static void register_ftrace_direct_cb(struct rcu_head *rhp)
5899{
5900 struct ftrace_hash *fhp = container_of(rhp, struct ftrace_hash, rcu);
5901
5902 free_ftrace_hash(fhp);
5903}
5904
5905/**
5906 * register_ftrace_direct - Call a custom trampoline directly
5907 * for multiple functions registered in @ops
5908 * @ops: The address of the struct ftrace_ops object
5909 * @addr: The address of the trampoline to call at @ops functions
5910 *
5911 * This is used to connect a direct calls to @addr from the nop locations
5912 * of the functions registered in @ops (with by ftrace_set_filter_ip
5913 * function).
5914 *
5915 * The location that it calls (@addr) must be able to handle a direct call,
5916 * and save the parameters of the function being traced, and restore them
5917 * (or inject new ones if needed), before returning.
5918 *
5919 * Returns:
5920 * 0 on success
5921 * -EINVAL - The @ops object was already registered with this call or
5922 * when there are no functions in @ops object.
5923 * -EBUSY - Another direct function is already attached (there can be only one)
5924 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5925 * -ENOMEM - There was an allocation failure.
5926 */
5927int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5928{
5929 struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL;
5930 struct ftrace_func_entry *entry, *new;
5931 int err = -EBUSY, size, i;
5932
5933 if (ops->func || ops->trampoline)
5934 return -EINVAL;
5935 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5936 return -EINVAL;
5937 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5938 return -EINVAL;
5939
5940 hash = ops->func_hash->filter_hash;
5941 if (ftrace_hash_empty(hash))
5942 return -EINVAL;
5943
5944 mutex_lock(&direct_mutex);
5945
5946 /* Make sure requested entries are not already registered.. */
5947 size = 1 << hash->size_bits;
5948 for (i = 0; i < size; i++) {
5949 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5950 if (ftrace_find_rec_direct(entry->ip))
5951 goto out_unlock;
5952 }
5953 }
5954
5955 err = -ENOMEM;
5956
5957 /* Make a copy hash to place the new and the old entries in */
5958 size = hash->count + direct_functions->count;
5959 if (size > 32)
5960 size = 32;
5961 new_hash = alloc_ftrace_hash(fls(size));
5962 if (!new_hash)
5963 goto out_unlock;
5964
5965 /* Now copy over the existing direct entries */
5966 size = 1 << direct_functions->size_bits;
5967 for (i = 0; i < size; i++) {
5968 hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) {
5969 new = add_hash_entry(new_hash, entry->ip);
5970 if (!new)
5971 goto out_unlock;
5972 new->direct = entry->direct;
5973 }
5974 }
5975
5976 /* ... and add the new entries */
5977 size = 1 << hash->size_bits;
5978 for (i = 0; i < size; i++) {
5979 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5980 new = add_hash_entry(new_hash, entry->ip);
5981 if (!new)
5982 goto out_unlock;
5983 /* Update both the copy and the hash entry */
5984 new->direct = addr;
5985 entry->direct = addr;
5986 }
5987 }
5988
5989 free_hash = direct_functions;
5990 rcu_assign_pointer(direct_functions, new_hash);
5991 new_hash = NULL;
5992
5993 ops->func = call_direct_funcs;
5994 ops->flags = MULTI_FLAGS;
5995 ops->trampoline = FTRACE_REGS_ADDR;
5996 ops->direct_call = addr;
5997
5998 err = register_ftrace_function_nolock(ops);
5999
6000 out_unlock:
6001 mutex_unlock(&direct_mutex);
6002
6003 if (free_hash && free_hash != EMPTY_HASH)
6004 call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb);
6005
6006 if (new_hash)
6007 free_ftrace_hash(new_hash);
6008
6009 return err;
6010}
6011EXPORT_SYMBOL_GPL(register_ftrace_direct);
6012
6013/**
6014 * unregister_ftrace_direct - Remove calls to custom trampoline
6015 * previously registered by register_ftrace_direct for @ops object.
6016 * @ops: The address of the struct ftrace_ops object
6017 * @addr: The address of the direct function that is called by the @ops functions
6018 * @free_filters: Set to true to remove all filters for the ftrace_ops, false otherwise
6019 *
6020 * This is used to remove a direct calls to @addr from the nop locations
6021 * of the functions registered in @ops (with by ftrace_set_filter_ip
6022 * function).
6023 *
6024 * Returns:
6025 * 0 on success
6026 * -EINVAL - The @ops object was not properly registered.
6027 */
6028int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
6029 bool free_filters)
6030{
6031 struct ftrace_hash *hash = ops->func_hash->filter_hash;
6032 int err;
6033
6034 if (check_direct_multi(ops))
6035 return -EINVAL;
6036 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6037 return -EINVAL;
6038
6039 mutex_lock(&direct_mutex);
6040 err = unregister_ftrace_function(ops);
6041 remove_direct_functions_hash(hash, addr);
6042 mutex_unlock(&direct_mutex);
6043
6044 /* cleanup for possible another register call */
6045 ops->func = NULL;
6046 ops->trampoline = 0;
6047
6048 if (free_filters)
6049 ftrace_free_filter(ops);
6050 return err;
6051}
6052EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
6053
6054static int
6055__modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
6056{
6057 struct ftrace_hash *hash;
6058 struct ftrace_func_entry *entry, *iter;
6059 static struct ftrace_ops tmp_ops = {
6060 .func = ftrace_stub,
6061 .flags = FTRACE_OPS_FL_STUB,
6062 };
6063 int i, size;
6064 int err;
6065
6066 lockdep_assert_held_once(&direct_mutex);
6067
6068 /* Enable the tmp_ops to have the same functions as the direct ops */
6069 ftrace_ops_init(&tmp_ops);
6070 tmp_ops.func_hash = ops->func_hash;
6071 tmp_ops.direct_call = addr;
6072
6073 err = register_ftrace_function_nolock(&tmp_ops);
6074 if (err)
6075 return err;
6076
6077 /*
6078 * Now the ftrace_ops_list_func() is called to do the direct callers.
6079 * We can safely change the direct functions attached to each entry.
6080 */
6081 mutex_lock(&ftrace_lock);
6082
6083 hash = ops->func_hash->filter_hash;
6084 size = 1 << hash->size_bits;
6085 for (i = 0; i < size; i++) {
6086 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
6087 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
6088 if (!entry)
6089 continue;
6090 entry->direct = addr;
6091 }
6092 }
6093 /* Prevent store tearing if a trampoline concurrently accesses the value */
6094 WRITE_ONCE(ops->direct_call, addr);
6095
6096 mutex_unlock(&ftrace_lock);
6097
6098 /* Removing the tmp_ops will add the updated direct callers to the functions */
6099 unregister_ftrace_function(&tmp_ops);
6100
6101 return err;
6102}
6103
6104/**
6105 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
6106 * to call something else
6107 * @ops: The address of the struct ftrace_ops object
6108 * @addr: The address of the new trampoline to call at @ops functions
6109 *
6110 * This is used to unregister currently registered direct caller and
6111 * register new one @addr on functions registered in @ops object.
6112 *
6113 * Note there's window between ftrace_shutdown and ftrace_startup calls
6114 * where there will be no callbacks called.
6115 *
6116 * Caller should already have direct_mutex locked, so we don't lock
6117 * direct_mutex here.
6118 *
6119 * Returns: zero on success. Non zero on error, which includes:
6120 * -EINVAL - The @ops object was not properly registered.
6121 */
6122int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
6123{
6124 if (check_direct_multi(ops))
6125 return -EINVAL;
6126 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6127 return -EINVAL;
6128
6129 return __modify_ftrace_direct(ops, addr);
6130}
6131EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
6132
6133/**
6134 * modify_ftrace_direct - Modify an existing direct 'multi' call
6135 * to call something else
6136 * @ops: The address of the struct ftrace_ops object
6137 * @addr: The address of the new trampoline to call at @ops functions
6138 *
6139 * This is used to unregister currently registered direct caller and
6140 * register new one @addr on functions registered in @ops object.
6141 *
6142 * Note there's window between ftrace_shutdown and ftrace_startup calls
6143 * where there will be no callbacks called.
6144 *
6145 * Returns: zero on success. Non zero on error, which includes:
6146 * -EINVAL - The @ops object was not properly registered.
6147 */
6148int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
6149{
6150 int err;
6151
6152 if (check_direct_multi(ops))
6153 return -EINVAL;
6154 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6155 return -EINVAL;
6156
6157 mutex_lock(&direct_mutex);
6158 err = __modify_ftrace_direct(ops, addr);
6159 mutex_unlock(&direct_mutex);
6160 return err;
6161}
6162EXPORT_SYMBOL_GPL(modify_ftrace_direct);
6163#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
6164
6165/**
6166 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
6167 * @ops: the ops to set the filter with
6168 * @ip: the address to add to or remove from the filter.
6169 * @remove: non zero to remove the ip from the filter
6170 * @reset: non zero to reset all filters before applying this filter.
6171 *
6172 * Filters denote which functions should be enabled when tracing is enabled
6173 * If @ip is NULL, it fails to update filter.
6174 *
6175 * This can allocate memory which must be freed before @ops can be freed,
6176 * either by removing each filtered addr or by using
6177 * ftrace_free_filter(@ops).
6178 */
6179int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
6180 int remove, int reset)
6181{
6182 ftrace_ops_init(ops);
6183 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
6184}
6185EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
6186
6187/**
6188 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
6189 * @ops: the ops to set the filter with
6190 * @ips: the array of addresses to add to or remove from the filter.
6191 * @cnt: the number of addresses in @ips
6192 * @remove: non zero to remove ips from the filter
6193 * @reset: non zero to reset all filters before applying this filter.
6194 *
6195 * Filters denote which functions should be enabled when tracing is enabled
6196 * If @ips array or any ip specified within is NULL , it fails to update filter.
6197 *
6198 * This can allocate memory which must be freed before @ops can be freed,
6199 * either by removing each filtered addr or by using
6200 * ftrace_free_filter(@ops).
6201*/
6202int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
6203 unsigned int cnt, int remove, int reset)
6204{
6205 ftrace_ops_init(ops);
6206 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
6207}
6208EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
6209
6210/**
6211 * ftrace_ops_set_global_filter - setup ops to use global filters
6212 * @ops: the ops which will use the global filters
6213 *
6214 * ftrace users who need global function trace filtering should call this.
6215 * It can set the global filter only if ops were not initialized before.
6216 */
6217void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
6218{
6219 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
6220 return;
6221
6222 ftrace_ops_init(ops);
6223 ops->func_hash = &global_ops.local_hash;
6224}
6225EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
6226
6227static int
6228ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
6229 int reset, int enable)
6230{
6231 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
6232}
6233
6234/**
6235 * ftrace_set_filter - set a function to filter on in ftrace
6236 * @ops: the ops to set the filter with
6237 * @buf: the string that holds the function filter text.
6238 * @len: the length of the string.
6239 * @reset: non-zero to reset all filters before applying this filter.
6240 *
6241 * Filters denote which functions should be enabled when tracing is enabled.
6242 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
6243 *
6244 * This can allocate memory which must be freed before @ops can be freed,
6245 * either by removing each filtered addr or by using
6246 * ftrace_free_filter(@ops).
6247 */
6248int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
6249 int len, int reset)
6250{
6251 ftrace_ops_init(ops);
6252 return ftrace_set_regex(ops, buf, len, reset, 1);
6253}
6254EXPORT_SYMBOL_GPL(ftrace_set_filter);
6255
6256/**
6257 * ftrace_set_notrace - set a function to not trace in ftrace
6258 * @ops: the ops to set the notrace filter with
6259 * @buf: the string that holds the function notrace text.
6260 * @len: the length of the string.
6261 * @reset: non-zero to reset all filters before applying this filter.
6262 *
6263 * Notrace Filters denote which functions should not be enabled when tracing
6264 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
6265 * for tracing.
6266 *
6267 * This can allocate memory which must be freed before @ops can be freed,
6268 * either by removing each filtered addr or by using
6269 * ftrace_free_filter(@ops).
6270 */
6271int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
6272 int len, int reset)
6273{
6274 ftrace_ops_init(ops);
6275 return ftrace_set_regex(ops, buf, len, reset, 0);
6276}
6277EXPORT_SYMBOL_GPL(ftrace_set_notrace);
6278/**
6279 * ftrace_set_global_filter - set a function to filter on with global tracers
6280 * @buf: the string that holds the function filter text.
6281 * @len: the length of the string.
6282 * @reset: non-zero to reset all filters before applying this filter.
6283 *
6284 * Filters denote which functions should be enabled when tracing is enabled.
6285 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
6286 */
6287void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
6288{
6289 ftrace_set_regex(&global_ops, buf, len, reset, 1);
6290}
6291EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
6292
6293/**
6294 * ftrace_set_global_notrace - set a function to not trace with global tracers
6295 * @buf: the string that holds the function notrace text.
6296 * @len: the length of the string.
6297 * @reset: non-zero to reset all filters before applying this filter.
6298 *
6299 * Notrace Filters denote which functions should not be enabled when tracing
6300 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
6301 * for tracing.
6302 */
6303void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
6304{
6305 ftrace_set_regex(&global_ops, buf, len, reset, 0);
6306}
6307EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
6308
6309/*
6310 * command line interface to allow users to set filters on boot up.
6311 */
6312#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
6313static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
6314static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
6315
6316/* Used by function selftest to not test if filter is set */
6317bool ftrace_filter_param __initdata;
6318
6319static int __init set_ftrace_notrace(char *str)
6320{
6321 ftrace_filter_param = true;
6322 strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
6323 return 1;
6324}
6325__setup("ftrace_notrace=", set_ftrace_notrace);
6326
6327static int __init set_ftrace_filter(char *str)
6328{
6329 ftrace_filter_param = true;
6330 strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
6331 return 1;
6332}
6333__setup("ftrace_filter=", set_ftrace_filter);
6334
6335#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6336static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
6337static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
6338static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
6339
6340static int __init set_graph_function(char *str)
6341{
6342 strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
6343 return 1;
6344}
6345__setup("ftrace_graph_filter=", set_graph_function);
6346
6347static int __init set_graph_notrace_function(char *str)
6348{
6349 strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
6350 return 1;
6351}
6352__setup("ftrace_graph_notrace=", set_graph_notrace_function);
6353
6354static int __init set_graph_max_depth_function(char *str)
6355{
6356 if (!str || kstrtouint(str, 0, &fgraph_max_depth))
6357 return 0;
6358 return 1;
6359}
6360__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
6361
6362static void __init set_ftrace_early_graph(char *buf, int enable)
6363{
6364 int ret;
6365 char *func;
6366 struct ftrace_hash *hash;
6367
6368 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
6369 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
6370 return;
6371
6372 while (buf) {
6373 func = strsep(&buf, ",");
6374 /* we allow only one expression at a time */
6375 ret = ftrace_graph_set_hash(hash, func);
6376 if (ret)
6377 printk(KERN_DEBUG "ftrace: function %s not "
6378 "traceable\n", func);
6379 }
6380
6381 if (enable)
6382 ftrace_graph_hash = hash;
6383 else
6384 ftrace_graph_notrace_hash = hash;
6385}
6386#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6387
6388void __init
6389ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
6390{
6391 char *func;
6392
6393 ftrace_ops_init(ops);
6394
6395 while (buf) {
6396 func = strsep(&buf, ",");
6397 ftrace_set_regex(ops, func, strlen(func), 0, enable);
6398 }
6399}
6400
6401static void __init set_ftrace_early_filters(void)
6402{
6403 if (ftrace_filter_buf[0])
6404 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
6405 if (ftrace_notrace_buf[0])
6406 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
6407#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6408 if (ftrace_graph_buf[0])
6409 set_ftrace_early_graph(ftrace_graph_buf, 1);
6410 if (ftrace_graph_notrace_buf[0])
6411 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
6412#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6413}
6414
6415int ftrace_regex_release(struct inode *inode, struct file *file)
6416{
6417 struct seq_file *m = (struct seq_file *)file->private_data;
6418 struct ftrace_iterator *iter;
6419 struct ftrace_hash **orig_hash;
6420 struct trace_parser *parser;
6421 int filter_hash;
6422
6423 if (file->f_mode & FMODE_READ) {
6424 iter = m->private;
6425 seq_release(inode, file);
6426 } else
6427 iter = file->private_data;
6428
6429 parser = &iter->parser;
6430 if (trace_parser_loaded(parser)) {
6431 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
6432
6433 ftrace_process_regex(iter, parser->buffer,
6434 parser->idx, enable);
6435 }
6436
6437 trace_parser_put(parser);
6438
6439 mutex_lock(&iter->ops->func_hash->regex_lock);
6440
6441 if (file->f_mode & FMODE_WRITE) {
6442 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
6443
6444 if (filter_hash) {
6445 orig_hash = &iter->ops->func_hash->filter_hash;
6446 if (iter->tr) {
6447 if (list_empty(&iter->tr->mod_trace))
6448 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
6449 else
6450 iter->hash->flags |= FTRACE_HASH_FL_MOD;
6451 }
6452 } else
6453 orig_hash = &iter->ops->func_hash->notrace_hash;
6454
6455 mutex_lock(&ftrace_lock);
6456 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
6457 iter->hash, filter_hash);
6458 mutex_unlock(&ftrace_lock);
6459 } else {
6460 /* For read only, the hash is the ops hash */
6461 iter->hash = NULL;
6462 }
6463
6464 mutex_unlock(&iter->ops->func_hash->regex_lock);
6465 free_ftrace_hash(iter->hash);
6466 if (iter->tr)
6467 trace_array_put(iter->tr);
6468 kfree(iter);
6469
6470 return 0;
6471}
6472
6473static const struct file_operations ftrace_avail_fops = {
6474 .open = ftrace_avail_open,
6475 .read = seq_read,
6476 .llseek = seq_lseek,
6477 .release = seq_release_private,
6478};
6479
6480static const struct file_operations ftrace_enabled_fops = {
6481 .open = ftrace_enabled_open,
6482 .read = seq_read,
6483 .llseek = seq_lseek,
6484 .release = seq_release_private,
6485};
6486
6487static const struct file_operations ftrace_touched_fops = {
6488 .open = ftrace_touched_open,
6489 .read = seq_read,
6490 .llseek = seq_lseek,
6491 .release = seq_release_private,
6492};
6493
6494static const struct file_operations ftrace_avail_addrs_fops = {
6495 .open = ftrace_avail_addrs_open,
6496 .read = seq_read,
6497 .llseek = seq_lseek,
6498 .release = seq_release_private,
6499};
6500
6501static const struct file_operations ftrace_filter_fops = {
6502 .open = ftrace_filter_open,
6503 .read = seq_read,
6504 .write = ftrace_filter_write,
6505 .llseek = tracing_lseek,
6506 .release = ftrace_regex_release,
6507};
6508
6509static const struct file_operations ftrace_notrace_fops = {
6510 .open = ftrace_notrace_open,
6511 .read = seq_read,
6512 .write = ftrace_notrace_write,
6513 .llseek = tracing_lseek,
6514 .release = ftrace_regex_release,
6515};
6516
6517#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6518
6519static DEFINE_MUTEX(graph_lock);
6520
6521struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
6522struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
6523
6524enum graph_filter_type {
6525 GRAPH_FILTER_NOTRACE = 0,
6526 GRAPH_FILTER_FUNCTION,
6527};
6528
6529#define FTRACE_GRAPH_EMPTY ((void *)1)
6530
6531struct ftrace_graph_data {
6532 struct ftrace_hash *hash;
6533 struct ftrace_func_entry *entry;
6534 int idx; /* for hash table iteration */
6535 enum graph_filter_type type;
6536 struct ftrace_hash *new_hash;
6537 const struct seq_operations *seq_ops;
6538 struct trace_parser parser;
6539};
6540
6541static void *
6542__g_next(struct seq_file *m, loff_t *pos)
6543{
6544 struct ftrace_graph_data *fgd = m->private;
6545 struct ftrace_func_entry *entry = fgd->entry;
6546 struct hlist_head *head;
6547 int i, idx = fgd->idx;
6548
6549 if (*pos >= fgd->hash->count)
6550 return NULL;
6551
6552 if (entry) {
6553 hlist_for_each_entry_continue(entry, hlist) {
6554 fgd->entry = entry;
6555 return entry;
6556 }
6557
6558 idx++;
6559 }
6560
6561 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6562 head = &fgd->hash->buckets[i];
6563 hlist_for_each_entry(entry, head, hlist) {
6564 fgd->entry = entry;
6565 fgd->idx = i;
6566 return entry;
6567 }
6568 }
6569 return NULL;
6570}
6571
6572static void *
6573g_next(struct seq_file *m, void *v, loff_t *pos)
6574{
6575 (*pos)++;
6576 return __g_next(m, pos);
6577}
6578
6579static void *g_start(struct seq_file *m, loff_t *pos)
6580{
6581 struct ftrace_graph_data *fgd = m->private;
6582
6583 mutex_lock(&graph_lock);
6584
6585 if (fgd->type == GRAPH_FILTER_FUNCTION)
6586 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6587 lockdep_is_held(&graph_lock));
6588 else
6589 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6590 lockdep_is_held(&graph_lock));
6591
6592 /* Nothing, tell g_show to print all functions are enabled */
6593 if (ftrace_hash_empty(fgd->hash) && !*pos)
6594 return FTRACE_GRAPH_EMPTY;
6595
6596 fgd->idx = 0;
6597 fgd->entry = NULL;
6598 return __g_next(m, pos);
6599}
6600
6601static void g_stop(struct seq_file *m, void *p)
6602{
6603 mutex_unlock(&graph_lock);
6604}
6605
6606static int g_show(struct seq_file *m, void *v)
6607{
6608 struct ftrace_func_entry *entry = v;
6609
6610 if (!entry)
6611 return 0;
6612
6613 if (entry == FTRACE_GRAPH_EMPTY) {
6614 struct ftrace_graph_data *fgd = m->private;
6615
6616 if (fgd->type == GRAPH_FILTER_FUNCTION)
6617 seq_puts(m, "#### all functions enabled ####\n");
6618 else
6619 seq_puts(m, "#### no functions disabled ####\n");
6620 return 0;
6621 }
6622
6623 seq_printf(m, "%ps\n", (void *)entry->ip);
6624
6625 return 0;
6626}
6627
6628static const struct seq_operations ftrace_graph_seq_ops = {
6629 .start = g_start,
6630 .next = g_next,
6631 .stop = g_stop,
6632 .show = g_show,
6633};
6634
6635static int
6636__ftrace_graph_open(struct inode *inode, struct file *file,
6637 struct ftrace_graph_data *fgd)
6638{
6639 int ret;
6640 struct ftrace_hash *new_hash = NULL;
6641
6642 ret = security_locked_down(LOCKDOWN_TRACEFS);
6643 if (ret)
6644 return ret;
6645
6646 if (file->f_mode & FMODE_WRITE) {
6647 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6648
6649 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6650 return -ENOMEM;
6651
6652 if (file->f_flags & O_TRUNC)
6653 new_hash = alloc_ftrace_hash(size_bits);
6654 else
6655 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6656 fgd->hash);
6657 if (!new_hash) {
6658 ret = -ENOMEM;
6659 goto out;
6660 }
6661 }
6662
6663 if (file->f_mode & FMODE_READ) {
6664 ret = seq_open(file, &ftrace_graph_seq_ops);
6665 if (!ret) {
6666 struct seq_file *m = file->private_data;
6667 m->private = fgd;
6668 } else {
6669 /* Failed */
6670 free_ftrace_hash(new_hash);
6671 new_hash = NULL;
6672 }
6673 } else
6674 file->private_data = fgd;
6675
6676out:
6677 if (ret < 0 && file->f_mode & FMODE_WRITE)
6678 trace_parser_put(&fgd->parser);
6679
6680 fgd->new_hash = new_hash;
6681
6682 /*
6683 * All uses of fgd->hash must be taken with the graph_lock
6684 * held. The graph_lock is going to be released, so force
6685 * fgd->hash to be reinitialized when it is taken again.
6686 */
6687 fgd->hash = NULL;
6688
6689 return ret;
6690}
6691
6692static int
6693ftrace_graph_open(struct inode *inode, struct file *file)
6694{
6695 struct ftrace_graph_data *fgd;
6696 int ret;
6697
6698 if (unlikely(ftrace_disabled))
6699 return -ENODEV;
6700
6701 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6702 if (fgd == NULL)
6703 return -ENOMEM;
6704
6705 mutex_lock(&graph_lock);
6706
6707 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6708 lockdep_is_held(&graph_lock));
6709 fgd->type = GRAPH_FILTER_FUNCTION;
6710 fgd->seq_ops = &ftrace_graph_seq_ops;
6711
6712 ret = __ftrace_graph_open(inode, file, fgd);
6713 if (ret < 0)
6714 kfree(fgd);
6715
6716 mutex_unlock(&graph_lock);
6717 return ret;
6718}
6719
6720static int
6721ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6722{
6723 struct ftrace_graph_data *fgd;
6724 int ret;
6725
6726 if (unlikely(ftrace_disabled))
6727 return -ENODEV;
6728
6729 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6730 if (fgd == NULL)
6731 return -ENOMEM;
6732
6733 mutex_lock(&graph_lock);
6734
6735 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6736 lockdep_is_held(&graph_lock));
6737 fgd->type = GRAPH_FILTER_NOTRACE;
6738 fgd->seq_ops = &ftrace_graph_seq_ops;
6739
6740 ret = __ftrace_graph_open(inode, file, fgd);
6741 if (ret < 0)
6742 kfree(fgd);
6743
6744 mutex_unlock(&graph_lock);
6745 return ret;
6746}
6747
6748static int
6749ftrace_graph_release(struct inode *inode, struct file *file)
6750{
6751 struct ftrace_graph_data *fgd;
6752 struct ftrace_hash *old_hash, *new_hash;
6753 struct trace_parser *parser;
6754 int ret = 0;
6755
6756 if (file->f_mode & FMODE_READ) {
6757 struct seq_file *m = file->private_data;
6758
6759 fgd = m->private;
6760 seq_release(inode, file);
6761 } else {
6762 fgd = file->private_data;
6763 }
6764
6765
6766 if (file->f_mode & FMODE_WRITE) {
6767
6768 parser = &fgd->parser;
6769
6770 if (trace_parser_loaded((parser))) {
6771 ret = ftrace_graph_set_hash(fgd->new_hash,
6772 parser->buffer);
6773 }
6774
6775 trace_parser_put(parser);
6776
6777 new_hash = __ftrace_hash_move(fgd->new_hash);
6778 if (!new_hash) {
6779 ret = -ENOMEM;
6780 goto out;
6781 }
6782
6783 mutex_lock(&graph_lock);
6784
6785 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6786 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6787 lockdep_is_held(&graph_lock));
6788 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6789 } else {
6790 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6791 lockdep_is_held(&graph_lock));
6792 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6793 }
6794
6795 mutex_unlock(&graph_lock);
6796
6797 /*
6798 * We need to do a hard force of sched synchronization.
6799 * This is because we use preempt_disable() to do RCU, but
6800 * the function tracers can be called where RCU is not watching
6801 * (like before user_exit()). We can not rely on the RCU
6802 * infrastructure to do the synchronization, thus we must do it
6803 * ourselves.
6804 */
6805 if (old_hash != EMPTY_HASH)
6806 synchronize_rcu_tasks_rude();
6807
6808 free_ftrace_hash(old_hash);
6809 }
6810
6811 out:
6812 free_ftrace_hash(fgd->new_hash);
6813 kfree(fgd);
6814
6815 return ret;
6816}
6817
6818static int
6819ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6820{
6821 struct ftrace_glob func_g;
6822 struct dyn_ftrace *rec;
6823 struct ftrace_page *pg;
6824 struct ftrace_func_entry *entry;
6825 int fail = 1;
6826 int not;
6827
6828 /* decode regex */
6829 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6830 &func_g.search, ¬);
6831
6832 func_g.len = strlen(func_g.search);
6833
6834 guard(mutex)(&ftrace_lock);
6835
6836 if (unlikely(ftrace_disabled))
6837 return -ENODEV;
6838
6839 do_for_each_ftrace_rec(pg, rec) {
6840
6841 if (rec->flags & FTRACE_FL_DISABLED)
6842 continue;
6843
6844 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6845 entry = ftrace_lookup_ip(hash, rec->ip);
6846
6847 if (!not) {
6848 fail = 0;
6849
6850 if (entry)
6851 continue;
6852 if (add_hash_entry(hash, rec->ip) == NULL)
6853 return 0;
6854 } else {
6855 if (entry) {
6856 free_hash_entry(hash, entry);
6857 fail = 0;
6858 }
6859 }
6860 }
6861 } while_for_each_ftrace_rec();
6862
6863 return fail ? -EINVAL : 0;
6864}
6865
6866static ssize_t
6867ftrace_graph_write(struct file *file, const char __user *ubuf,
6868 size_t cnt, loff_t *ppos)
6869{
6870 ssize_t read, ret = 0;
6871 struct ftrace_graph_data *fgd = file->private_data;
6872 struct trace_parser *parser;
6873
6874 if (!cnt)
6875 return 0;
6876
6877 /* Read mode uses seq functions */
6878 if (file->f_mode & FMODE_READ) {
6879 struct seq_file *m = file->private_data;
6880 fgd = m->private;
6881 }
6882
6883 parser = &fgd->parser;
6884
6885 read = trace_get_user(parser, ubuf, cnt, ppos);
6886
6887 if (read >= 0 && trace_parser_loaded(parser) &&
6888 !trace_parser_cont(parser)) {
6889
6890 ret = ftrace_graph_set_hash(fgd->new_hash,
6891 parser->buffer);
6892 trace_parser_clear(parser);
6893 }
6894
6895 if (!ret)
6896 ret = read;
6897
6898 return ret;
6899}
6900
6901static const struct file_operations ftrace_graph_fops = {
6902 .open = ftrace_graph_open,
6903 .read = seq_read,
6904 .write = ftrace_graph_write,
6905 .llseek = tracing_lseek,
6906 .release = ftrace_graph_release,
6907};
6908
6909static const struct file_operations ftrace_graph_notrace_fops = {
6910 .open = ftrace_graph_notrace_open,
6911 .read = seq_read,
6912 .write = ftrace_graph_write,
6913 .llseek = tracing_lseek,
6914 .release = ftrace_graph_release,
6915};
6916#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6917
6918void ftrace_create_filter_files(struct ftrace_ops *ops,
6919 struct dentry *parent)
6920{
6921
6922 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6923 ops, &ftrace_filter_fops);
6924
6925 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6926 ops, &ftrace_notrace_fops);
6927}
6928
6929/*
6930 * The name "destroy_filter_files" is really a misnomer. Although
6931 * in the future, it may actually delete the files, but this is
6932 * really intended to make sure the ops passed in are disabled
6933 * and that when this function returns, the caller is free to
6934 * free the ops.
6935 *
6936 * The "destroy" name is only to match the "create" name that this
6937 * should be paired with.
6938 */
6939void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6940{
6941 mutex_lock(&ftrace_lock);
6942 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6943 ftrace_shutdown(ops, 0);
6944 ops->flags |= FTRACE_OPS_FL_DELETED;
6945 ftrace_free_filter(ops);
6946 mutex_unlock(&ftrace_lock);
6947}
6948
6949static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6950{
6951
6952 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6953 d_tracer, NULL, &ftrace_avail_fops);
6954
6955 trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6956 d_tracer, NULL, &ftrace_avail_addrs_fops);
6957
6958 trace_create_file("enabled_functions", TRACE_MODE_READ,
6959 d_tracer, NULL, &ftrace_enabled_fops);
6960
6961 trace_create_file("touched_functions", TRACE_MODE_READ,
6962 d_tracer, NULL, &ftrace_touched_fops);
6963
6964 ftrace_create_filter_files(&global_ops, d_tracer);
6965
6966#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6967 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6968 NULL,
6969 &ftrace_graph_fops);
6970 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6971 NULL,
6972 &ftrace_graph_notrace_fops);
6973#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6974
6975 return 0;
6976}
6977
6978static int ftrace_cmp_ips(const void *a, const void *b)
6979{
6980 const unsigned long *ipa = a;
6981 const unsigned long *ipb = b;
6982
6983 if (*ipa > *ipb)
6984 return 1;
6985 if (*ipa < *ipb)
6986 return -1;
6987 return 0;
6988}
6989
6990#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6991static void test_is_sorted(unsigned long *start, unsigned long count)
6992{
6993 int i;
6994
6995 for (i = 1; i < count; i++) {
6996 if (WARN(start[i - 1] > start[i],
6997 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6998 (void *)start[i - 1], start[i - 1],
6999 (void *)start[i], start[i]))
7000 break;
7001 }
7002 if (i == count)
7003 pr_info("ftrace section at %px sorted properly\n", start);
7004}
7005#else
7006static void test_is_sorted(unsigned long *start, unsigned long count)
7007{
7008}
7009#endif
7010
7011static int ftrace_process_locs(struct module *mod,
7012 unsigned long *start,
7013 unsigned long *end)
7014{
7015 struct ftrace_page *pg_unuse = NULL;
7016 struct ftrace_page *start_pg;
7017 struct ftrace_page *pg;
7018 struct dyn_ftrace *rec;
7019 unsigned long skipped = 0;
7020 unsigned long count;
7021 unsigned long *p;
7022 unsigned long addr;
7023 unsigned long flags = 0; /* Shut up gcc */
7024 int ret = -ENOMEM;
7025
7026 count = end - start;
7027
7028 if (!count)
7029 return 0;
7030
7031 /*
7032 * Sorting mcount in vmlinux at build time depend on
7033 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
7034 * modules can not be sorted at build time.
7035 */
7036 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
7037 sort(start, count, sizeof(*start),
7038 ftrace_cmp_ips, NULL);
7039 } else {
7040 test_is_sorted(start, count);
7041 }
7042
7043 start_pg = ftrace_allocate_pages(count);
7044 if (!start_pg)
7045 return -ENOMEM;
7046
7047 mutex_lock(&ftrace_lock);
7048
7049 /*
7050 * Core and each module needs their own pages, as
7051 * modules will free them when they are removed.
7052 * Force a new page to be allocated for modules.
7053 */
7054 if (!mod) {
7055 WARN_ON(ftrace_pages || ftrace_pages_start);
7056 /* First initialization */
7057 ftrace_pages = ftrace_pages_start = start_pg;
7058 } else {
7059 if (!ftrace_pages)
7060 goto out;
7061
7062 if (WARN_ON(ftrace_pages->next)) {
7063 /* Hmm, we have free pages? */
7064 while (ftrace_pages->next)
7065 ftrace_pages = ftrace_pages->next;
7066 }
7067
7068 ftrace_pages->next = start_pg;
7069 }
7070
7071 p = start;
7072 pg = start_pg;
7073 while (p < end) {
7074 unsigned long end_offset;
7075 addr = ftrace_call_adjust(*p++);
7076 /*
7077 * Some architecture linkers will pad between
7078 * the different mcount_loc sections of different
7079 * object files to satisfy alignments.
7080 * Skip any NULL pointers.
7081 */
7082 if (!addr) {
7083 skipped++;
7084 continue;
7085 }
7086
7087 end_offset = (pg->index+1) * sizeof(pg->records[0]);
7088 if (end_offset > PAGE_SIZE << pg->order) {
7089 /* We should have allocated enough */
7090 if (WARN_ON(!pg->next))
7091 break;
7092 pg = pg->next;
7093 }
7094
7095 rec = &pg->records[pg->index++];
7096 rec->ip = addr;
7097 }
7098
7099 if (pg->next) {
7100 pg_unuse = pg->next;
7101 pg->next = NULL;
7102 }
7103
7104 /* Assign the last page to ftrace_pages */
7105 ftrace_pages = pg;
7106
7107 /*
7108 * We only need to disable interrupts on start up
7109 * because we are modifying code that an interrupt
7110 * may execute, and the modification is not atomic.
7111 * But for modules, nothing runs the code we modify
7112 * until we are finished with it, and there's no
7113 * reason to cause large interrupt latencies while we do it.
7114 */
7115 if (!mod)
7116 local_irq_save(flags);
7117 ftrace_update_code(mod, start_pg);
7118 if (!mod)
7119 local_irq_restore(flags);
7120 ret = 0;
7121 out:
7122 mutex_unlock(&ftrace_lock);
7123
7124 /* We should have used all pages unless we skipped some */
7125 if (pg_unuse) {
7126 WARN_ON(!skipped);
7127 /* Need to synchronize with ftrace_location_range() */
7128 synchronize_rcu();
7129 ftrace_free_pages(pg_unuse);
7130 }
7131 return ret;
7132}
7133
7134struct ftrace_mod_func {
7135 struct list_head list;
7136 char *name;
7137 unsigned long ip;
7138 unsigned int size;
7139};
7140
7141struct ftrace_mod_map {
7142 struct rcu_head rcu;
7143 struct list_head list;
7144 struct module *mod;
7145 unsigned long start_addr;
7146 unsigned long end_addr;
7147 struct list_head funcs;
7148 unsigned int num_funcs;
7149};
7150
7151static int ftrace_get_trampoline_kallsym(unsigned int symnum,
7152 unsigned long *value, char *type,
7153 char *name, char *module_name,
7154 int *exported)
7155{
7156 struct ftrace_ops *op;
7157
7158 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
7159 if (!op->trampoline || symnum--)
7160 continue;
7161 *value = op->trampoline;
7162 *type = 't';
7163 strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
7164 strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
7165 *exported = 0;
7166 return 0;
7167 }
7168
7169 return -ERANGE;
7170}
7171
7172#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
7173/*
7174 * Check if the current ops references the given ip.
7175 *
7176 * If the ops traces all functions, then it was already accounted for.
7177 * If the ops does not trace the current record function, skip it.
7178 * If the ops ignores the function via notrace filter, skip it.
7179 */
7180static bool
7181ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
7182{
7183 /* If ops isn't enabled, ignore it */
7184 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
7185 return false;
7186
7187 /* If ops traces all then it includes this function */
7188 if (ops_traces_mod(ops))
7189 return true;
7190
7191 /* The function must be in the filter */
7192 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
7193 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
7194 return false;
7195
7196 /* If in notrace hash, we ignore it too */
7197 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
7198 return false;
7199
7200 return true;
7201}
7202#endif
7203
7204#ifdef CONFIG_MODULES
7205
7206#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
7207
7208static LIST_HEAD(ftrace_mod_maps);
7209
7210static int referenced_filters(struct dyn_ftrace *rec)
7211{
7212 struct ftrace_ops *ops;
7213 int cnt = 0;
7214
7215 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
7216 if (ops_references_ip(ops, rec->ip)) {
7217 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
7218 continue;
7219 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7220 continue;
7221 cnt++;
7222 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
7223 rec->flags |= FTRACE_FL_REGS;
7224 if (cnt == 1 && ops->trampoline)
7225 rec->flags |= FTRACE_FL_TRAMP;
7226 else
7227 rec->flags &= ~FTRACE_FL_TRAMP;
7228 }
7229 }
7230
7231 return cnt;
7232}
7233
7234static void
7235clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
7236{
7237 struct ftrace_func_entry *entry;
7238 struct dyn_ftrace *rec;
7239 int i;
7240
7241 if (ftrace_hash_empty(hash))
7242 return;
7243
7244 for (i = 0; i < pg->index; i++) {
7245 rec = &pg->records[i];
7246 entry = __ftrace_lookup_ip(hash, rec->ip);
7247 /*
7248 * Do not allow this rec to match again.
7249 * Yeah, it may waste some memory, but will be removed
7250 * if/when the hash is modified again.
7251 */
7252 if (entry)
7253 entry->ip = 0;
7254 }
7255}
7256
7257/* Clear any records from hashes */
7258static void clear_mod_from_hashes(struct ftrace_page *pg)
7259{
7260 struct trace_array *tr;
7261
7262 mutex_lock(&trace_types_lock);
7263 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7264 if (!tr->ops || !tr->ops->func_hash)
7265 continue;
7266 mutex_lock(&tr->ops->func_hash->regex_lock);
7267 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
7268 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
7269 mutex_unlock(&tr->ops->func_hash->regex_lock);
7270 }
7271 mutex_unlock(&trace_types_lock);
7272}
7273
7274static void ftrace_free_mod_map(struct rcu_head *rcu)
7275{
7276 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
7277 struct ftrace_mod_func *mod_func;
7278 struct ftrace_mod_func *n;
7279
7280 /* All the contents of mod_map are now not visible to readers */
7281 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
7282 kfree(mod_func->name);
7283 list_del(&mod_func->list);
7284 kfree(mod_func);
7285 }
7286
7287 kfree(mod_map);
7288}
7289
7290void ftrace_release_mod(struct module *mod)
7291{
7292 struct ftrace_mod_map *mod_map;
7293 struct ftrace_mod_map *n;
7294 struct dyn_ftrace *rec;
7295 struct ftrace_page **last_pg;
7296 struct ftrace_page *tmp_page = NULL;
7297 struct ftrace_page *pg;
7298
7299 mutex_lock(&ftrace_lock);
7300
7301 if (ftrace_disabled)
7302 goto out_unlock;
7303
7304 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
7305 if (mod_map->mod == mod) {
7306 list_del_rcu(&mod_map->list);
7307 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
7308 break;
7309 }
7310 }
7311
7312 /*
7313 * Each module has its own ftrace_pages, remove
7314 * them from the list.
7315 */
7316 last_pg = &ftrace_pages_start;
7317 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
7318 rec = &pg->records[0];
7319 if (within_module(rec->ip, mod)) {
7320 /*
7321 * As core pages are first, the first
7322 * page should never be a module page.
7323 */
7324 if (WARN_ON(pg == ftrace_pages_start))
7325 goto out_unlock;
7326
7327 /* Check if we are deleting the last page */
7328 if (pg == ftrace_pages)
7329 ftrace_pages = next_to_ftrace_page(last_pg);
7330
7331 ftrace_update_tot_cnt -= pg->index;
7332 *last_pg = pg->next;
7333
7334 pg->next = tmp_page;
7335 tmp_page = pg;
7336 } else
7337 last_pg = &pg->next;
7338 }
7339 out_unlock:
7340 mutex_unlock(&ftrace_lock);
7341
7342 /* Need to synchronize with ftrace_location_range() */
7343 if (tmp_page)
7344 synchronize_rcu();
7345 for (pg = tmp_page; pg; pg = tmp_page) {
7346
7347 /* Needs to be called outside of ftrace_lock */
7348 clear_mod_from_hashes(pg);
7349
7350 if (pg->records) {
7351 free_pages((unsigned long)pg->records, pg->order);
7352 ftrace_number_of_pages -= 1 << pg->order;
7353 }
7354 tmp_page = pg->next;
7355 kfree(pg);
7356 ftrace_number_of_groups--;
7357 }
7358}
7359
7360void ftrace_module_enable(struct module *mod)
7361{
7362 struct dyn_ftrace *rec;
7363 struct ftrace_page *pg;
7364
7365 mutex_lock(&ftrace_lock);
7366
7367 if (ftrace_disabled)
7368 goto out_unlock;
7369
7370 /*
7371 * If the tracing is enabled, go ahead and enable the record.
7372 *
7373 * The reason not to enable the record immediately is the
7374 * inherent check of ftrace_make_nop/ftrace_make_call for
7375 * correct previous instructions. Making first the NOP
7376 * conversion puts the module to the correct state, thus
7377 * passing the ftrace_make_call check.
7378 *
7379 * We also delay this to after the module code already set the
7380 * text to read-only, as we now need to set it back to read-write
7381 * so that we can modify the text.
7382 */
7383 if (ftrace_start_up)
7384 ftrace_arch_code_modify_prepare();
7385
7386 do_for_each_ftrace_rec(pg, rec) {
7387 int cnt;
7388 /*
7389 * do_for_each_ftrace_rec() is a double loop.
7390 * module text shares the pg. If a record is
7391 * not part of this module, then skip this pg,
7392 * which the "break" will do.
7393 */
7394 if (!within_module(rec->ip, mod))
7395 break;
7396
7397 /* Weak functions should still be ignored */
7398 if (!test_for_valid_rec(rec)) {
7399 /* Clear all other flags. Should not be enabled anyway */
7400 rec->flags = FTRACE_FL_DISABLED;
7401 continue;
7402 }
7403
7404 cnt = 0;
7405
7406 /*
7407 * When adding a module, we need to check if tracers are
7408 * currently enabled and if they are, and can trace this record,
7409 * we need to enable the module functions as well as update the
7410 * reference counts for those function records.
7411 */
7412 if (ftrace_start_up)
7413 cnt += referenced_filters(rec);
7414
7415 rec->flags &= ~FTRACE_FL_DISABLED;
7416 rec->flags += cnt;
7417
7418 if (ftrace_start_up && cnt) {
7419 int failed = __ftrace_replace_code(rec, 1);
7420 if (failed) {
7421 ftrace_bug(failed, rec);
7422 goto out_loop;
7423 }
7424 }
7425
7426 } while_for_each_ftrace_rec();
7427
7428 out_loop:
7429 if (ftrace_start_up)
7430 ftrace_arch_code_modify_post_process();
7431
7432 out_unlock:
7433 mutex_unlock(&ftrace_lock);
7434
7435 process_cached_mods(mod->name);
7436}
7437
7438void ftrace_module_init(struct module *mod)
7439{
7440 int ret;
7441
7442 if (ftrace_disabled || !mod->num_ftrace_callsites)
7443 return;
7444
7445 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
7446 mod->ftrace_callsites + mod->num_ftrace_callsites);
7447 if (ret)
7448 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
7449 mod->name);
7450}
7451
7452static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7453 struct dyn_ftrace *rec)
7454{
7455 struct ftrace_mod_func *mod_func;
7456 unsigned long symsize;
7457 unsigned long offset;
7458 char str[KSYM_SYMBOL_LEN];
7459 char *modname;
7460 const char *ret;
7461
7462 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
7463 if (!ret)
7464 return;
7465
7466 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
7467 if (!mod_func)
7468 return;
7469
7470 mod_func->name = kstrdup(str, GFP_KERNEL);
7471 if (!mod_func->name) {
7472 kfree(mod_func);
7473 return;
7474 }
7475
7476 mod_func->ip = rec->ip - offset;
7477 mod_func->size = symsize;
7478
7479 mod_map->num_funcs++;
7480
7481 list_add_rcu(&mod_func->list, &mod_map->funcs);
7482}
7483
7484static struct ftrace_mod_map *
7485allocate_ftrace_mod_map(struct module *mod,
7486 unsigned long start, unsigned long end)
7487{
7488 struct ftrace_mod_map *mod_map;
7489
7490 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
7491 if (!mod_map)
7492 return NULL;
7493
7494 mod_map->mod = mod;
7495 mod_map->start_addr = start;
7496 mod_map->end_addr = end;
7497 mod_map->num_funcs = 0;
7498
7499 INIT_LIST_HEAD_RCU(&mod_map->funcs);
7500
7501 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
7502
7503 return mod_map;
7504}
7505
7506static int
7507ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
7508 unsigned long addr, unsigned long *size,
7509 unsigned long *off, char *sym)
7510{
7511 struct ftrace_mod_func *found_func = NULL;
7512 struct ftrace_mod_func *mod_func;
7513
7514 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7515 if (addr >= mod_func->ip &&
7516 addr < mod_func->ip + mod_func->size) {
7517 found_func = mod_func;
7518 break;
7519 }
7520 }
7521
7522 if (found_func) {
7523 if (size)
7524 *size = found_func->size;
7525 if (off)
7526 *off = addr - found_func->ip;
7527 return strscpy(sym, found_func->name, KSYM_NAME_LEN);
7528 }
7529
7530 return 0;
7531}
7532
7533int
7534ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7535 unsigned long *off, char **modname, char *sym)
7536{
7537 struct ftrace_mod_map *mod_map;
7538 int ret = 0;
7539
7540 /* mod_map is freed via call_rcu() */
7541 preempt_disable();
7542 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7543 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7544 if (ret) {
7545 if (modname)
7546 *modname = mod_map->mod->name;
7547 break;
7548 }
7549 }
7550 preempt_enable();
7551
7552 return ret;
7553}
7554
7555int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7556 char *type, char *name,
7557 char *module_name, int *exported)
7558{
7559 struct ftrace_mod_map *mod_map;
7560 struct ftrace_mod_func *mod_func;
7561 int ret;
7562
7563 preempt_disable();
7564 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7565
7566 if (symnum >= mod_map->num_funcs) {
7567 symnum -= mod_map->num_funcs;
7568 continue;
7569 }
7570
7571 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7572 if (symnum > 1) {
7573 symnum--;
7574 continue;
7575 }
7576
7577 *value = mod_func->ip;
7578 *type = 'T';
7579 strscpy(name, mod_func->name, KSYM_NAME_LEN);
7580 strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7581 *exported = 1;
7582 preempt_enable();
7583 return 0;
7584 }
7585 WARN_ON(1);
7586 break;
7587 }
7588 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7589 module_name, exported);
7590 preempt_enable();
7591 return ret;
7592}
7593
7594#else
7595static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7596 struct dyn_ftrace *rec) { }
7597static inline struct ftrace_mod_map *
7598allocate_ftrace_mod_map(struct module *mod,
7599 unsigned long start, unsigned long end)
7600{
7601 return NULL;
7602}
7603int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7604 char *type, char *name, char *module_name,
7605 int *exported)
7606{
7607 int ret;
7608
7609 preempt_disable();
7610 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7611 module_name, exported);
7612 preempt_enable();
7613 return ret;
7614}
7615#endif /* CONFIG_MODULES */
7616
7617struct ftrace_init_func {
7618 struct list_head list;
7619 unsigned long ip;
7620};
7621
7622/* Clear any init ips from hashes */
7623static void
7624clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7625{
7626 struct ftrace_func_entry *entry;
7627
7628 entry = ftrace_lookup_ip(hash, func->ip);
7629 /*
7630 * Do not allow this rec to match again.
7631 * Yeah, it may waste some memory, but will be removed
7632 * if/when the hash is modified again.
7633 */
7634 if (entry)
7635 entry->ip = 0;
7636}
7637
7638static void
7639clear_func_from_hashes(struct ftrace_init_func *func)
7640{
7641 struct trace_array *tr;
7642
7643 mutex_lock(&trace_types_lock);
7644 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7645 if (!tr->ops || !tr->ops->func_hash)
7646 continue;
7647 mutex_lock(&tr->ops->func_hash->regex_lock);
7648 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7649 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7650 mutex_unlock(&tr->ops->func_hash->regex_lock);
7651 }
7652 mutex_unlock(&trace_types_lock);
7653}
7654
7655static void add_to_clear_hash_list(struct list_head *clear_list,
7656 struct dyn_ftrace *rec)
7657{
7658 struct ftrace_init_func *func;
7659
7660 func = kmalloc(sizeof(*func), GFP_KERNEL);
7661 if (!func) {
7662 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7663 return;
7664 }
7665
7666 func->ip = rec->ip;
7667 list_add(&func->list, clear_list);
7668}
7669
7670void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7671{
7672 unsigned long start = (unsigned long)(start_ptr);
7673 unsigned long end = (unsigned long)(end_ptr);
7674 struct ftrace_page **last_pg = &ftrace_pages_start;
7675 struct ftrace_page *tmp_page = NULL;
7676 struct ftrace_page *pg;
7677 struct dyn_ftrace *rec;
7678 struct dyn_ftrace key;
7679 struct ftrace_mod_map *mod_map = NULL;
7680 struct ftrace_init_func *func, *func_next;
7681 LIST_HEAD(clear_hash);
7682
7683 key.ip = start;
7684 key.flags = end; /* overload flags, as it is unsigned long */
7685
7686 mutex_lock(&ftrace_lock);
7687
7688 /*
7689 * If we are freeing module init memory, then check if
7690 * any tracer is active. If so, we need to save a mapping of
7691 * the module functions being freed with the address.
7692 */
7693 if (mod && ftrace_ops_list != &ftrace_list_end)
7694 mod_map = allocate_ftrace_mod_map(mod, start, end);
7695
7696 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7697 if (end < pg->records[0].ip ||
7698 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7699 continue;
7700 again:
7701 rec = bsearch(&key, pg->records, pg->index,
7702 sizeof(struct dyn_ftrace),
7703 ftrace_cmp_recs);
7704 if (!rec)
7705 continue;
7706
7707 /* rec will be cleared from hashes after ftrace_lock unlock */
7708 add_to_clear_hash_list(&clear_hash, rec);
7709
7710 if (mod_map)
7711 save_ftrace_mod_rec(mod_map, rec);
7712
7713 pg->index--;
7714 ftrace_update_tot_cnt--;
7715 if (!pg->index) {
7716 *last_pg = pg->next;
7717 pg->next = tmp_page;
7718 tmp_page = pg;
7719 pg = container_of(last_pg, struct ftrace_page, next);
7720 if (!(*last_pg))
7721 ftrace_pages = pg;
7722 continue;
7723 }
7724 memmove(rec, rec + 1,
7725 (pg->index - (rec - pg->records)) * sizeof(*rec));
7726 /* More than one function may be in this block */
7727 goto again;
7728 }
7729 mutex_unlock(&ftrace_lock);
7730
7731 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7732 clear_func_from_hashes(func);
7733 kfree(func);
7734 }
7735 /* Need to synchronize with ftrace_location_range() */
7736 if (tmp_page) {
7737 synchronize_rcu();
7738 ftrace_free_pages(tmp_page);
7739 }
7740}
7741
7742void __init ftrace_free_init_mem(void)
7743{
7744 void *start = (void *)(&__init_begin);
7745 void *end = (void *)(&__init_end);
7746
7747 ftrace_boot_snapshot();
7748
7749 ftrace_free_mem(NULL, start, end);
7750}
7751
7752int __init __weak ftrace_dyn_arch_init(void)
7753{
7754 return 0;
7755}
7756
7757void __init ftrace_init(void)
7758{
7759 extern unsigned long __start_mcount_loc[];
7760 extern unsigned long __stop_mcount_loc[];
7761 unsigned long count, flags;
7762 int ret;
7763
7764 local_irq_save(flags);
7765 ret = ftrace_dyn_arch_init();
7766 local_irq_restore(flags);
7767 if (ret)
7768 goto failed;
7769
7770 count = __stop_mcount_loc - __start_mcount_loc;
7771 if (!count) {
7772 pr_info("ftrace: No functions to be traced?\n");
7773 goto failed;
7774 }
7775
7776 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7777 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7778
7779 ret = ftrace_process_locs(NULL,
7780 __start_mcount_loc,
7781 __stop_mcount_loc);
7782 if (ret) {
7783 pr_warn("ftrace: failed to allocate entries for functions\n");
7784 goto failed;
7785 }
7786
7787 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7788 ftrace_number_of_pages, ftrace_number_of_groups);
7789
7790 last_ftrace_enabled = ftrace_enabled = 1;
7791
7792 set_ftrace_early_filters();
7793
7794 return;
7795 failed:
7796 ftrace_disabled = 1;
7797}
7798
7799/* Do nothing if arch does not support this */
7800void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7801{
7802}
7803
7804static void ftrace_update_trampoline(struct ftrace_ops *ops)
7805{
7806 unsigned long trampoline = ops->trampoline;
7807
7808 arch_ftrace_update_trampoline(ops);
7809 if (ops->trampoline && ops->trampoline != trampoline &&
7810 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7811 /* Add to kallsyms before the perf events */
7812 ftrace_add_trampoline_to_kallsyms(ops);
7813 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7814 ops->trampoline, ops->trampoline_size, false,
7815 FTRACE_TRAMPOLINE_SYM);
7816 /*
7817 * Record the perf text poke event after the ksymbol register
7818 * event.
7819 */
7820 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7821 (void *)ops->trampoline,
7822 ops->trampoline_size);
7823 }
7824}
7825
7826void ftrace_init_trace_array(struct trace_array *tr)
7827{
7828 INIT_LIST_HEAD(&tr->func_probes);
7829 INIT_LIST_HEAD(&tr->mod_trace);
7830 INIT_LIST_HEAD(&tr->mod_notrace);
7831}
7832#else
7833
7834struct ftrace_ops global_ops = {
7835 .func = ftrace_stub,
7836 .flags = FTRACE_OPS_FL_INITIALIZED |
7837 FTRACE_OPS_FL_PID,
7838};
7839
7840static int __init ftrace_nodyn_init(void)
7841{
7842 ftrace_enabled = 1;
7843 return 0;
7844}
7845core_initcall(ftrace_nodyn_init);
7846
7847static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7848static inline void ftrace_startup_all(int command) { }
7849
7850static void ftrace_update_trampoline(struct ftrace_ops *ops)
7851{
7852}
7853
7854#endif /* CONFIG_DYNAMIC_FTRACE */
7855
7856__init void ftrace_init_global_array_ops(struct trace_array *tr)
7857{
7858 tr->ops = &global_ops;
7859 tr->ops->private = tr;
7860 ftrace_init_trace_array(tr);
7861 init_array_fgraph_ops(tr, tr->ops);
7862}
7863
7864void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7865{
7866 /* If we filter on pids, update to use the pid function */
7867 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7868 if (WARN_ON(tr->ops->func != ftrace_stub))
7869 printk("ftrace ops had %pS for function\n",
7870 tr->ops->func);
7871 }
7872 tr->ops->func = func;
7873 tr->ops->private = tr;
7874}
7875
7876void ftrace_reset_array_ops(struct trace_array *tr)
7877{
7878 tr->ops->func = ftrace_stub;
7879}
7880
7881static nokprobe_inline void
7882__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7883 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7884{
7885 struct pt_regs *regs = ftrace_get_regs(fregs);
7886 struct ftrace_ops *op;
7887 int bit;
7888
7889 /*
7890 * The ftrace_test_and_set_recursion() will disable preemption,
7891 * which is required since some of the ops may be dynamically
7892 * allocated, they must be freed after a synchronize_rcu().
7893 */
7894 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7895 if (bit < 0)
7896 return;
7897
7898 do_for_each_ftrace_op(op, ftrace_ops_list) {
7899 /* Stub functions don't need to be called nor tested */
7900 if (op->flags & FTRACE_OPS_FL_STUB)
7901 continue;
7902 /*
7903 * Check the following for each ops before calling their func:
7904 * if RCU flag is set, then rcu_is_watching() must be true
7905 * Otherwise test if the ip matches the ops filter
7906 *
7907 * If any of the above fails then the op->func() is not executed.
7908 */
7909 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7910 ftrace_ops_test(op, ip, regs)) {
7911 if (FTRACE_WARN_ON(!op->func)) {
7912 pr_warn("op=%p %pS\n", op, op);
7913 goto out;
7914 }
7915 op->func(ip, parent_ip, op, fregs);
7916 }
7917 } while_for_each_ftrace_op(op);
7918out:
7919 trace_clear_recursion(bit);
7920}
7921
7922/*
7923 * Some archs only support passing ip and parent_ip. Even though
7924 * the list function ignores the op parameter, we do not want any
7925 * C side effects, where a function is called without the caller
7926 * sending a third parameter.
7927 * Archs are to support both the regs and ftrace_ops at the same time.
7928 * If they support ftrace_ops, it is assumed they support regs.
7929 * If call backs want to use regs, they must either check for regs
7930 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7931 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7932 * An architecture can pass partial regs with ftrace_ops and still
7933 * set the ARCH_SUPPORTS_FTRACE_OPS.
7934 *
7935 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7936 * arch_ftrace_ops_list_func.
7937 */
7938#if ARCH_SUPPORTS_FTRACE_OPS
7939void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7940 struct ftrace_ops *op, struct ftrace_regs *fregs)
7941{
7942 kmsan_unpoison_memory(fregs, ftrace_regs_size());
7943 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7944}
7945#else
7946void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7947{
7948 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7949}
7950#endif
7951NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7952
7953/*
7954 * If there's only one function registered but it does not support
7955 * recursion, needs RCU protection, then this function will be called
7956 * by the mcount trampoline.
7957 */
7958static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7959 struct ftrace_ops *op, struct ftrace_regs *fregs)
7960{
7961 int bit;
7962
7963 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7964 if (bit < 0)
7965 return;
7966
7967 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7968 op->func(ip, parent_ip, op, fregs);
7969
7970 trace_clear_recursion(bit);
7971}
7972NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7973
7974/**
7975 * ftrace_ops_get_func - get the function a trampoline should call
7976 * @ops: the ops to get the function for
7977 *
7978 * Normally the mcount trampoline will call the ops->func, but there
7979 * are times that it should not. For example, if the ops does not
7980 * have its own recursion protection, then it should call the
7981 * ftrace_ops_assist_func() instead.
7982 *
7983 * Returns: the function that the trampoline should call for @ops.
7984 */
7985ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7986{
7987 /*
7988 * If the function does not handle recursion or needs to be RCU safe,
7989 * then we need to call the assist handler.
7990 */
7991 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7992 FTRACE_OPS_FL_RCU))
7993 return ftrace_ops_assist_func;
7994
7995 return ops->func;
7996}
7997
7998static void
7999ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
8000 struct task_struct *prev,
8001 struct task_struct *next,
8002 unsigned int prev_state)
8003{
8004 struct trace_array *tr = data;
8005 struct trace_pid_list *pid_list;
8006 struct trace_pid_list *no_pid_list;
8007
8008 pid_list = rcu_dereference_sched(tr->function_pids);
8009 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
8010
8011 if (trace_ignore_this_task(pid_list, no_pid_list, next))
8012 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
8013 FTRACE_PID_IGNORE);
8014 else
8015 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
8016 next->pid);
8017}
8018
8019static void
8020ftrace_pid_follow_sched_process_fork(void *data,
8021 struct task_struct *self,
8022 struct task_struct *task)
8023{
8024 struct trace_pid_list *pid_list;
8025 struct trace_array *tr = data;
8026
8027 pid_list = rcu_dereference_sched(tr->function_pids);
8028 trace_filter_add_remove_task(pid_list, self, task);
8029
8030 pid_list = rcu_dereference_sched(tr->function_no_pids);
8031 trace_filter_add_remove_task(pid_list, self, task);
8032}
8033
8034static void
8035ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
8036{
8037 struct trace_pid_list *pid_list;
8038 struct trace_array *tr = data;
8039
8040 pid_list = rcu_dereference_sched(tr->function_pids);
8041 trace_filter_add_remove_task(pid_list, NULL, task);
8042
8043 pid_list = rcu_dereference_sched(tr->function_no_pids);
8044 trace_filter_add_remove_task(pid_list, NULL, task);
8045}
8046
8047void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
8048{
8049 if (enable) {
8050 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
8051 tr);
8052 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
8053 tr);
8054 } else {
8055 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
8056 tr);
8057 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
8058 tr);
8059 }
8060}
8061
8062static void clear_ftrace_pids(struct trace_array *tr, int type)
8063{
8064 struct trace_pid_list *pid_list;
8065 struct trace_pid_list *no_pid_list;
8066 int cpu;
8067
8068 pid_list = rcu_dereference_protected(tr->function_pids,
8069 lockdep_is_held(&ftrace_lock));
8070 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
8071 lockdep_is_held(&ftrace_lock));
8072
8073 /* Make sure there's something to do */
8074 if (!pid_type_enabled(type, pid_list, no_pid_list))
8075 return;
8076
8077 /* See if the pids still need to be checked after this */
8078 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
8079 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
8080 for_each_possible_cpu(cpu)
8081 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
8082 }
8083
8084 if (type & TRACE_PIDS)
8085 rcu_assign_pointer(tr->function_pids, NULL);
8086
8087 if (type & TRACE_NO_PIDS)
8088 rcu_assign_pointer(tr->function_no_pids, NULL);
8089
8090 /* Wait till all users are no longer using pid filtering */
8091 synchronize_rcu();
8092
8093 if ((type & TRACE_PIDS) && pid_list)
8094 trace_pid_list_free(pid_list);
8095
8096 if ((type & TRACE_NO_PIDS) && no_pid_list)
8097 trace_pid_list_free(no_pid_list);
8098}
8099
8100void ftrace_clear_pids(struct trace_array *tr)
8101{
8102 mutex_lock(&ftrace_lock);
8103
8104 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
8105
8106 mutex_unlock(&ftrace_lock);
8107}
8108
8109static void ftrace_pid_reset(struct trace_array *tr, int type)
8110{
8111 mutex_lock(&ftrace_lock);
8112 clear_ftrace_pids(tr, type);
8113
8114 ftrace_update_pid_func();
8115 ftrace_startup_all(0);
8116
8117 mutex_unlock(&ftrace_lock);
8118}
8119
8120/* Greater than any max PID */
8121#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
8122
8123static void *fpid_start(struct seq_file *m, loff_t *pos)
8124 __acquires(RCU)
8125{
8126 struct trace_pid_list *pid_list;
8127 struct trace_array *tr = m->private;
8128
8129 mutex_lock(&ftrace_lock);
8130 rcu_read_lock_sched();
8131
8132 pid_list = rcu_dereference_sched(tr->function_pids);
8133
8134 if (!pid_list)
8135 return !(*pos) ? FTRACE_NO_PIDS : NULL;
8136
8137 return trace_pid_start(pid_list, pos);
8138}
8139
8140static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
8141{
8142 struct trace_array *tr = m->private;
8143 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
8144
8145 if (v == FTRACE_NO_PIDS) {
8146 (*pos)++;
8147 return NULL;
8148 }
8149 return trace_pid_next(pid_list, v, pos);
8150}
8151
8152static void fpid_stop(struct seq_file *m, void *p)
8153 __releases(RCU)
8154{
8155 rcu_read_unlock_sched();
8156 mutex_unlock(&ftrace_lock);
8157}
8158
8159static int fpid_show(struct seq_file *m, void *v)
8160{
8161 if (v == FTRACE_NO_PIDS) {
8162 seq_puts(m, "no pid\n");
8163 return 0;
8164 }
8165
8166 return trace_pid_show(m, v);
8167}
8168
8169static const struct seq_operations ftrace_pid_sops = {
8170 .start = fpid_start,
8171 .next = fpid_next,
8172 .stop = fpid_stop,
8173 .show = fpid_show,
8174};
8175
8176static void *fnpid_start(struct seq_file *m, loff_t *pos)
8177 __acquires(RCU)
8178{
8179 struct trace_pid_list *pid_list;
8180 struct trace_array *tr = m->private;
8181
8182 mutex_lock(&ftrace_lock);
8183 rcu_read_lock_sched();
8184
8185 pid_list = rcu_dereference_sched(tr->function_no_pids);
8186
8187 if (!pid_list)
8188 return !(*pos) ? FTRACE_NO_PIDS : NULL;
8189
8190 return trace_pid_start(pid_list, pos);
8191}
8192
8193static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
8194{
8195 struct trace_array *tr = m->private;
8196 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
8197
8198 if (v == FTRACE_NO_PIDS) {
8199 (*pos)++;
8200 return NULL;
8201 }
8202 return trace_pid_next(pid_list, v, pos);
8203}
8204
8205static const struct seq_operations ftrace_no_pid_sops = {
8206 .start = fnpid_start,
8207 .next = fnpid_next,
8208 .stop = fpid_stop,
8209 .show = fpid_show,
8210};
8211
8212static int pid_open(struct inode *inode, struct file *file, int type)
8213{
8214 const struct seq_operations *seq_ops;
8215 struct trace_array *tr = inode->i_private;
8216 struct seq_file *m;
8217 int ret = 0;
8218
8219 ret = tracing_check_open_get_tr(tr);
8220 if (ret)
8221 return ret;
8222
8223 if ((file->f_mode & FMODE_WRITE) &&
8224 (file->f_flags & O_TRUNC))
8225 ftrace_pid_reset(tr, type);
8226
8227 switch (type) {
8228 case TRACE_PIDS:
8229 seq_ops = &ftrace_pid_sops;
8230 break;
8231 case TRACE_NO_PIDS:
8232 seq_ops = &ftrace_no_pid_sops;
8233 break;
8234 default:
8235 trace_array_put(tr);
8236 WARN_ON_ONCE(1);
8237 return -EINVAL;
8238 }
8239
8240 ret = seq_open(file, seq_ops);
8241 if (ret < 0) {
8242 trace_array_put(tr);
8243 } else {
8244 m = file->private_data;
8245 /* copy tr over to seq ops */
8246 m->private = tr;
8247 }
8248
8249 return ret;
8250}
8251
8252static int
8253ftrace_pid_open(struct inode *inode, struct file *file)
8254{
8255 return pid_open(inode, file, TRACE_PIDS);
8256}
8257
8258static int
8259ftrace_no_pid_open(struct inode *inode, struct file *file)
8260{
8261 return pid_open(inode, file, TRACE_NO_PIDS);
8262}
8263
8264static void ignore_task_cpu(void *data)
8265{
8266 struct trace_array *tr = data;
8267 struct trace_pid_list *pid_list;
8268 struct trace_pid_list *no_pid_list;
8269
8270 /*
8271 * This function is called by on_each_cpu() while the
8272 * event_mutex is held.
8273 */
8274 pid_list = rcu_dereference_protected(tr->function_pids,
8275 mutex_is_locked(&ftrace_lock));
8276 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
8277 mutex_is_locked(&ftrace_lock));
8278
8279 if (trace_ignore_this_task(pid_list, no_pid_list, current))
8280 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
8281 FTRACE_PID_IGNORE);
8282 else
8283 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
8284 current->pid);
8285}
8286
8287static ssize_t
8288pid_write(struct file *filp, const char __user *ubuf,
8289 size_t cnt, loff_t *ppos, int type)
8290{
8291 struct seq_file *m = filp->private_data;
8292 struct trace_array *tr = m->private;
8293 struct trace_pid_list *filtered_pids;
8294 struct trace_pid_list *other_pids;
8295 struct trace_pid_list *pid_list;
8296 ssize_t ret;
8297
8298 if (!cnt)
8299 return 0;
8300
8301 mutex_lock(&ftrace_lock);
8302
8303 switch (type) {
8304 case TRACE_PIDS:
8305 filtered_pids = rcu_dereference_protected(tr->function_pids,
8306 lockdep_is_held(&ftrace_lock));
8307 other_pids = rcu_dereference_protected(tr->function_no_pids,
8308 lockdep_is_held(&ftrace_lock));
8309 break;
8310 case TRACE_NO_PIDS:
8311 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
8312 lockdep_is_held(&ftrace_lock));
8313 other_pids = rcu_dereference_protected(tr->function_pids,
8314 lockdep_is_held(&ftrace_lock));
8315 break;
8316 default:
8317 ret = -EINVAL;
8318 WARN_ON_ONCE(1);
8319 goto out;
8320 }
8321
8322 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
8323 if (ret < 0)
8324 goto out;
8325
8326 switch (type) {
8327 case TRACE_PIDS:
8328 rcu_assign_pointer(tr->function_pids, pid_list);
8329 break;
8330 case TRACE_NO_PIDS:
8331 rcu_assign_pointer(tr->function_no_pids, pid_list);
8332 break;
8333 }
8334
8335
8336 if (filtered_pids) {
8337 synchronize_rcu();
8338 trace_pid_list_free(filtered_pids);
8339 } else if (pid_list && !other_pids) {
8340 /* Register a probe to set whether to ignore the tracing of a task */
8341 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
8342 }
8343
8344 /*
8345 * Ignoring of pids is done at task switch. But we have to
8346 * check for those tasks that are currently running.
8347 * Always do this in case a pid was appended or removed.
8348 */
8349 on_each_cpu(ignore_task_cpu, tr, 1);
8350
8351 ftrace_update_pid_func();
8352 ftrace_startup_all(0);
8353 out:
8354 mutex_unlock(&ftrace_lock);
8355
8356 if (ret > 0)
8357 *ppos += ret;
8358
8359 return ret;
8360}
8361
8362static ssize_t
8363ftrace_pid_write(struct file *filp, const char __user *ubuf,
8364 size_t cnt, loff_t *ppos)
8365{
8366 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
8367}
8368
8369static ssize_t
8370ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
8371 size_t cnt, loff_t *ppos)
8372{
8373 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
8374}
8375
8376static int
8377ftrace_pid_release(struct inode *inode, struct file *file)
8378{
8379 struct trace_array *tr = inode->i_private;
8380
8381 trace_array_put(tr);
8382
8383 return seq_release(inode, file);
8384}
8385
8386static const struct file_operations ftrace_pid_fops = {
8387 .open = ftrace_pid_open,
8388 .write = ftrace_pid_write,
8389 .read = seq_read,
8390 .llseek = tracing_lseek,
8391 .release = ftrace_pid_release,
8392};
8393
8394static const struct file_operations ftrace_no_pid_fops = {
8395 .open = ftrace_no_pid_open,
8396 .write = ftrace_no_pid_write,
8397 .read = seq_read,
8398 .llseek = tracing_lseek,
8399 .release = ftrace_pid_release,
8400};
8401
8402void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8403{
8404 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
8405 tr, &ftrace_pid_fops);
8406 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
8407 d_tracer, tr, &ftrace_no_pid_fops);
8408}
8409
8410void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
8411 struct dentry *d_tracer)
8412{
8413 /* Only the top level directory has the dyn_tracefs and profile */
8414 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
8415
8416 ftrace_init_dyn_tracefs(d_tracer);
8417 ftrace_profile_tracefs(d_tracer);
8418}
8419
8420/**
8421 * ftrace_kill - kill ftrace
8422 *
8423 * This function should be used by panic code. It stops ftrace
8424 * but in a not so nice way. If you need to simply kill ftrace
8425 * from a non-atomic section, use ftrace_kill.
8426 */
8427void ftrace_kill(void)
8428{
8429 ftrace_disabled = 1;
8430 ftrace_enabled = 0;
8431 ftrace_trace_function = ftrace_stub;
8432 kprobe_ftrace_kill();
8433}
8434
8435/**
8436 * ftrace_is_dead - Test if ftrace is dead or not.
8437 *
8438 * Returns: 1 if ftrace is "dead", zero otherwise.
8439 */
8440int ftrace_is_dead(void)
8441{
8442 return ftrace_disabled;
8443}
8444
8445#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
8446/*
8447 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
8448 * it doesn't conflict with any direct ftrace_ops. If there is existing
8449 * direct ftrace_ops on a kernel function being patched, call
8450 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
8451 *
8452 * @ops: ftrace_ops being registered.
8453 *
8454 * Returns:
8455 * 0 on success;
8456 * Negative on failure.
8457 */
8458static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8459{
8460 struct ftrace_func_entry *entry;
8461 struct ftrace_hash *hash;
8462 struct ftrace_ops *op;
8463 int size, i, ret;
8464
8465 lockdep_assert_held_once(&direct_mutex);
8466
8467 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8468 return 0;
8469
8470 hash = ops->func_hash->filter_hash;
8471 size = 1 << hash->size_bits;
8472 for (i = 0; i < size; i++) {
8473 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8474 unsigned long ip = entry->ip;
8475 bool found_op = false;
8476
8477 mutex_lock(&ftrace_lock);
8478 do_for_each_ftrace_op(op, ftrace_ops_list) {
8479 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8480 continue;
8481 if (ops_references_ip(op, ip)) {
8482 found_op = true;
8483 break;
8484 }
8485 } while_for_each_ftrace_op(op);
8486 mutex_unlock(&ftrace_lock);
8487
8488 if (found_op) {
8489 if (!op->ops_func)
8490 return -EBUSY;
8491
8492 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
8493 if (ret)
8494 return ret;
8495 }
8496 }
8497 }
8498
8499 return 0;
8500}
8501
8502/*
8503 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
8504 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
8505 * ops.
8506 */
8507static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8508{
8509 struct ftrace_func_entry *entry;
8510 struct ftrace_hash *hash;
8511 struct ftrace_ops *op;
8512 int size, i;
8513
8514 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8515 return;
8516
8517 mutex_lock(&direct_mutex);
8518
8519 hash = ops->func_hash->filter_hash;
8520 size = 1 << hash->size_bits;
8521 for (i = 0; i < size; i++) {
8522 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8523 unsigned long ip = entry->ip;
8524 bool found_op = false;
8525
8526 mutex_lock(&ftrace_lock);
8527 do_for_each_ftrace_op(op, ftrace_ops_list) {
8528 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8529 continue;
8530 if (ops_references_ip(op, ip)) {
8531 found_op = true;
8532 break;
8533 }
8534 } while_for_each_ftrace_op(op);
8535 mutex_unlock(&ftrace_lock);
8536
8537 /* The cleanup is optional, ignore any errors */
8538 if (found_op && op->ops_func)
8539 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8540 }
8541 }
8542 mutex_unlock(&direct_mutex);
8543}
8544
8545#define lock_direct_mutex() mutex_lock(&direct_mutex)
8546#define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8547
8548#else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8549
8550static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8551{
8552 return 0;
8553}
8554
8555static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8556{
8557}
8558
8559#define lock_direct_mutex() do { } while (0)
8560#define unlock_direct_mutex() do { } while (0)
8561
8562#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8563
8564/*
8565 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8566 */
8567static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8568{
8569 int ret;
8570
8571 ftrace_ops_init(ops);
8572
8573 mutex_lock(&ftrace_lock);
8574
8575 ret = ftrace_startup(ops, 0);
8576
8577 mutex_unlock(&ftrace_lock);
8578
8579 return ret;
8580}
8581
8582/**
8583 * register_ftrace_function - register a function for profiling
8584 * @ops: ops structure that holds the function for profiling.
8585 *
8586 * Register a function to be called by all functions in the
8587 * kernel.
8588 *
8589 * Note: @ops->func and all the functions it calls must be labeled
8590 * with "notrace", otherwise it will go into a
8591 * recursive loop.
8592 */
8593int register_ftrace_function(struct ftrace_ops *ops)
8594{
8595 int ret;
8596
8597 lock_direct_mutex();
8598 ret = prepare_direct_functions_for_ipmodify(ops);
8599 if (ret < 0)
8600 goto out_unlock;
8601
8602 ret = register_ftrace_function_nolock(ops);
8603
8604out_unlock:
8605 unlock_direct_mutex();
8606 return ret;
8607}
8608EXPORT_SYMBOL_GPL(register_ftrace_function);
8609
8610/**
8611 * unregister_ftrace_function - unregister a function for profiling.
8612 * @ops: ops structure that holds the function to unregister
8613 *
8614 * Unregister a function that was added to be called by ftrace profiling.
8615 */
8616int unregister_ftrace_function(struct ftrace_ops *ops)
8617{
8618 int ret;
8619
8620 mutex_lock(&ftrace_lock);
8621 ret = ftrace_shutdown(ops, 0);
8622 mutex_unlock(&ftrace_lock);
8623
8624 cleanup_direct_functions_after_ipmodify(ops);
8625 return ret;
8626}
8627EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8628
8629static int symbols_cmp(const void *a, const void *b)
8630{
8631 const char **str_a = (const char **) a;
8632 const char **str_b = (const char **) b;
8633
8634 return strcmp(*str_a, *str_b);
8635}
8636
8637struct kallsyms_data {
8638 unsigned long *addrs;
8639 const char **syms;
8640 size_t cnt;
8641 size_t found;
8642};
8643
8644/* This function gets called for all kernel and module symbols
8645 * and returns 1 in case we resolved all the requested symbols,
8646 * 0 otherwise.
8647 */
8648static int kallsyms_callback(void *data, const char *name, unsigned long addr)
8649{
8650 struct kallsyms_data *args = data;
8651 const char **sym;
8652 int idx;
8653
8654 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8655 if (!sym)
8656 return 0;
8657
8658 idx = sym - args->syms;
8659 if (args->addrs[idx])
8660 return 0;
8661
8662 if (!ftrace_location(addr))
8663 return 0;
8664
8665 args->addrs[idx] = addr;
8666 args->found++;
8667 return args->found == args->cnt ? 1 : 0;
8668}
8669
8670/**
8671 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8672 *
8673 * @sorted_syms: array of symbols pointers symbols to resolve,
8674 * must be alphabetically sorted
8675 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8676 * @addrs: array for storing resulting addresses
8677 *
8678 * This function looks up addresses for array of symbols provided in
8679 * @syms array (must be alphabetically sorted) and stores them in
8680 * @addrs array, which needs to be big enough to store at least @cnt
8681 * addresses.
8682 *
8683 * Returns: 0 if all provided symbols are found, -ESRCH otherwise.
8684 */
8685int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8686{
8687 struct kallsyms_data args;
8688 int found_all;
8689
8690 memset(addrs, 0, sizeof(*addrs) * cnt);
8691 args.addrs = addrs;
8692 args.syms = sorted_syms;
8693 args.cnt = cnt;
8694 args.found = 0;
8695
8696 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8697 if (found_all)
8698 return 0;
8699 found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8700 return found_all ? 0 : -ESRCH;
8701}
8702
8703#ifdef CONFIG_SYSCTL
8704
8705#ifdef CONFIG_DYNAMIC_FTRACE
8706static void ftrace_startup_sysctl(void)
8707{
8708 int command;
8709
8710 if (unlikely(ftrace_disabled))
8711 return;
8712
8713 /* Force update next time */
8714 saved_ftrace_func = NULL;
8715 /* ftrace_start_up is true if we want ftrace running */
8716 if (ftrace_start_up) {
8717 command = FTRACE_UPDATE_CALLS;
8718 if (ftrace_graph_active)
8719 command |= FTRACE_START_FUNC_RET;
8720 ftrace_startup_enable(command);
8721 }
8722}
8723
8724static void ftrace_shutdown_sysctl(void)
8725{
8726 int command;
8727
8728 if (unlikely(ftrace_disabled))
8729 return;
8730
8731 /* ftrace_start_up is true if ftrace is running */
8732 if (ftrace_start_up) {
8733 command = FTRACE_DISABLE_CALLS;
8734 if (ftrace_graph_active)
8735 command |= FTRACE_STOP_FUNC_RET;
8736 ftrace_run_update_code(command);
8737 }
8738}
8739#else
8740# define ftrace_startup_sysctl() do { } while (0)
8741# define ftrace_shutdown_sysctl() do { } while (0)
8742#endif /* CONFIG_DYNAMIC_FTRACE */
8743
8744static bool is_permanent_ops_registered(void)
8745{
8746 struct ftrace_ops *op;
8747
8748 do_for_each_ftrace_op(op, ftrace_ops_list) {
8749 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8750 return true;
8751 } while_for_each_ftrace_op(op);
8752
8753 return false;
8754}
8755
8756static int
8757ftrace_enable_sysctl(const struct ctl_table *table, int write,
8758 void *buffer, size_t *lenp, loff_t *ppos)
8759{
8760 int ret = -ENODEV;
8761
8762 mutex_lock(&ftrace_lock);
8763
8764 if (unlikely(ftrace_disabled))
8765 goto out;
8766
8767 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8768
8769 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8770 goto out;
8771
8772 if (ftrace_enabled) {
8773
8774 /* we are starting ftrace again */
8775 if (rcu_dereference_protected(ftrace_ops_list,
8776 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8777 update_ftrace_function();
8778
8779 ftrace_startup_sysctl();
8780
8781 } else {
8782 if (is_permanent_ops_registered()) {
8783 ftrace_enabled = true;
8784 ret = -EBUSY;
8785 goto out;
8786 }
8787
8788 /* stopping ftrace calls (just send to ftrace_stub) */
8789 ftrace_trace_function = ftrace_stub;
8790
8791 ftrace_shutdown_sysctl();
8792 }
8793
8794 last_ftrace_enabled = !!ftrace_enabled;
8795 out:
8796 mutex_unlock(&ftrace_lock);
8797 return ret;
8798}
8799
8800static struct ctl_table ftrace_sysctls[] = {
8801 {
8802 .procname = "ftrace_enabled",
8803 .data = &ftrace_enabled,
8804 .maxlen = sizeof(int),
8805 .mode = 0644,
8806 .proc_handler = ftrace_enable_sysctl,
8807 },
8808};
8809
8810static int __init ftrace_sysctl_init(void)
8811{
8812 register_sysctl_init("kernel", ftrace_sysctls);
8813 return 0;
8814}
8815late_initcall(ftrace_sysctl_init);
8816#endif