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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/sched/task.h>
19#include <linux/kallsyms.h>
20#include <linux/seq_file.h>
21#include <linux/suspend.h>
22#include <linux/tracefs.h>
23#include <linux/hardirq.h>
24#include <linux/kthread.h>
25#include <linux/uaccess.h>
26#include <linux/bsearch.h>
27#include <linux/module.h>
28#include <linux/ftrace.h>
29#include <linux/sysctl.h>
30#include <linux/slab.h>
31#include <linux/ctype.h>
32#include <linux/sort.h>
33#include <linux/list.h>
34#include <linux/hash.h>
35#include <linux/rcupdate.h>
36
37#include <trace/events/sched.h>
38
39#include <asm/sections.h>
40#include <asm/setup.h>
41
42#include "trace_output.h"
43#include "trace_stat.h"
44
45#define FTRACE_WARN_ON(cond) \
46 ({ \
47 int ___r = cond; \
48 if (WARN_ON(___r)) \
49 ftrace_kill(); \
50 ___r; \
51 })
52
53#define FTRACE_WARN_ON_ONCE(cond) \
54 ({ \
55 int ___r = cond; \
56 if (WARN_ON_ONCE(___r)) \
57 ftrace_kill(); \
58 ___r; \
59 })
60
61/* hash bits for specific function selection */
62#define FTRACE_HASH_BITS 7
63#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
64#define FTRACE_HASH_DEFAULT_BITS 10
65#define FTRACE_HASH_MAX_BITS 12
66
67#ifdef CONFIG_DYNAMIC_FTRACE
68#define INIT_OPS_HASH(opsname) \
69 .func_hash = &opsname.local_hash, \
70 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
71#define ASSIGN_OPS_HASH(opsname, val) \
72 .func_hash = val, \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
74#else
75#define INIT_OPS_HASH(opsname)
76#define ASSIGN_OPS_HASH(opsname, val)
77#endif
78
79static struct ftrace_ops ftrace_list_end __read_mostly = {
80 .func = ftrace_stub,
81 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
82 INIT_OPS_HASH(ftrace_list_end)
83};
84
85/* ftrace_enabled is a method to turn ftrace on or off */
86int ftrace_enabled __read_mostly;
87static int last_ftrace_enabled;
88
89/* Current function tracing op */
90struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
91/* What to set function_trace_op to */
92static struct ftrace_ops *set_function_trace_op;
93
94static bool ftrace_pids_enabled(struct ftrace_ops *ops)
95{
96 struct trace_array *tr;
97
98 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
99 return false;
100
101 tr = ops->private;
102
103 return tr->function_pids != NULL;
104}
105
106static void ftrace_update_trampoline(struct ftrace_ops *ops);
107
108/*
109 * ftrace_disabled is set when an anomaly is discovered.
110 * ftrace_disabled is much stronger than ftrace_enabled.
111 */
112static int ftrace_disabled __read_mostly;
113
114static DEFINE_MUTEX(ftrace_lock);
115
116static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
117ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
118static struct ftrace_ops global_ops;
119
120#if ARCH_SUPPORTS_FTRACE_OPS
121static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
122 struct ftrace_ops *op, struct pt_regs *regs);
123#else
124/* See comment below, where ftrace_ops_list_func is defined */
125static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
126#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
127#endif
128
129/*
130 * Traverse the ftrace_global_list, invoking all entries. The reason that we
131 * can use rcu_dereference_raw_notrace() is that elements removed from this list
132 * are simply leaked, so there is no need to interact with a grace-period
133 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
134 * concurrent insertions into the ftrace_global_list.
135 *
136 * Silly Alpha and silly pointer-speculation compiler optimizations!
137 */
138#define do_for_each_ftrace_op(op, list) \
139 op = rcu_dereference_raw_notrace(list); \
140 do
141
142/*
143 * Optimized for just a single item in the list (as that is the normal case).
144 */
145#define while_for_each_ftrace_op(op) \
146 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
147 unlikely((op) != &ftrace_list_end))
148
149static inline void ftrace_ops_init(struct ftrace_ops *ops)
150{
151#ifdef CONFIG_DYNAMIC_FTRACE
152 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
153 mutex_init(&ops->local_hash.regex_lock);
154 ops->func_hash = &ops->local_hash;
155 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
156 }
157#endif
158}
159
160/**
161 * ftrace_nr_registered_ops - return number of ops registered
162 *
163 * Returns the number of ftrace_ops registered and tracing functions
164 */
165int ftrace_nr_registered_ops(void)
166{
167 struct ftrace_ops *ops;
168 int cnt = 0;
169
170 mutex_lock(&ftrace_lock);
171
172 for (ops = rcu_dereference_protected(ftrace_ops_list,
173 lockdep_is_held(&ftrace_lock));
174 ops != &ftrace_list_end;
175 ops = rcu_dereference_protected(ops->next,
176 lockdep_is_held(&ftrace_lock)))
177 cnt++;
178
179 mutex_unlock(&ftrace_lock);
180
181 return cnt;
182}
183
184static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
185 struct ftrace_ops *op, struct pt_regs *regs)
186{
187 struct trace_array *tr = op->private;
188
189 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
190 return;
191
192 op->saved_func(ip, parent_ip, op, regs);
193}
194
195/**
196 * clear_ftrace_function - reset the ftrace function
197 *
198 * This NULLs the ftrace function and in essence stops
199 * tracing. There may be lag
200 */
201void clear_ftrace_function(void)
202{
203 ftrace_trace_function = ftrace_stub;
204}
205
206static void ftrace_sync(struct work_struct *work)
207{
208 /*
209 * This function is just a stub to implement a hard force
210 * of synchronize_sched(). This requires synchronizing
211 * tasks even in userspace and idle.
212 *
213 * Yes, function tracing is rude.
214 */
215}
216
217static void ftrace_sync_ipi(void *data)
218{
219 /* Probably not needed, but do it anyway */
220 smp_rmb();
221}
222
223#ifdef CONFIG_FUNCTION_GRAPH_TRACER
224static void update_function_graph_func(void);
225
226/* Both enabled by default (can be cleared by function_graph tracer flags */
227static bool fgraph_sleep_time = true;
228static bool fgraph_graph_time = true;
229
230#else
231static inline void update_function_graph_func(void) { }
232#endif
233
234
235static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
236{
237 /*
238 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
239 * then it needs to call the list anyway.
240 */
241 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
242 FTRACE_FORCE_LIST_FUNC)
243 return ftrace_ops_list_func;
244
245 return ftrace_ops_get_func(ops);
246}
247
248static void update_ftrace_function(void)
249{
250 ftrace_func_t func;
251
252 /*
253 * Prepare the ftrace_ops that the arch callback will use.
254 * If there's only one ftrace_ops registered, the ftrace_ops_list
255 * will point to the ops we want.
256 */
257 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
258 lockdep_is_held(&ftrace_lock));
259
260 /* If there's no ftrace_ops registered, just call the stub function */
261 if (set_function_trace_op == &ftrace_list_end) {
262 func = ftrace_stub;
263
264 /*
265 * If we are at the end of the list and this ops is
266 * recursion safe and not dynamic and the arch supports passing ops,
267 * then have the mcount trampoline call the function directly.
268 */
269 } else if (rcu_dereference_protected(ftrace_ops_list->next,
270 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
271 func = ftrace_ops_get_list_func(ftrace_ops_list);
272
273 } else {
274 /* Just use the default ftrace_ops */
275 set_function_trace_op = &ftrace_list_end;
276 func = ftrace_ops_list_func;
277 }
278
279 update_function_graph_func();
280
281 /* If there's no change, then do nothing more here */
282 if (ftrace_trace_function == func)
283 return;
284
285 /*
286 * If we are using the list function, it doesn't care
287 * about the function_trace_ops.
288 */
289 if (func == ftrace_ops_list_func) {
290 ftrace_trace_function = func;
291 /*
292 * Don't even bother setting function_trace_ops,
293 * it would be racy to do so anyway.
294 */
295 return;
296 }
297
298#ifndef CONFIG_DYNAMIC_FTRACE
299 /*
300 * For static tracing, we need to be a bit more careful.
301 * The function change takes affect immediately. Thus,
302 * we need to coorditate the setting of the function_trace_ops
303 * with the setting of the ftrace_trace_function.
304 *
305 * Set the function to the list ops, which will call the
306 * function we want, albeit indirectly, but it handles the
307 * ftrace_ops and doesn't depend on function_trace_op.
308 */
309 ftrace_trace_function = ftrace_ops_list_func;
310 /*
311 * Make sure all CPUs see this. Yes this is slow, but static
312 * tracing is slow and nasty to have enabled.
313 */
314 schedule_on_each_cpu(ftrace_sync);
315 /* Now all cpus are using the list ops. */
316 function_trace_op = set_function_trace_op;
317 /* Make sure the function_trace_op is visible on all CPUs */
318 smp_wmb();
319 /* Nasty way to force a rmb on all cpus */
320 smp_call_function(ftrace_sync_ipi, NULL, 1);
321 /* OK, we are all set to update the ftrace_trace_function now! */
322#endif /* !CONFIG_DYNAMIC_FTRACE */
323
324 ftrace_trace_function = func;
325}
326
327int using_ftrace_ops_list_func(void)
328{
329 return ftrace_trace_function == ftrace_ops_list_func;
330}
331
332static void add_ftrace_ops(struct ftrace_ops __rcu **list,
333 struct ftrace_ops *ops)
334{
335 rcu_assign_pointer(ops->next, *list);
336
337 /*
338 * We are entering ops into the list but another
339 * CPU might be walking that list. We need to make sure
340 * the ops->next pointer is valid before another CPU sees
341 * the ops pointer included into the list.
342 */
343 rcu_assign_pointer(*list, ops);
344}
345
346static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
347 struct ftrace_ops *ops)
348{
349 struct ftrace_ops **p;
350
351 /*
352 * If we are removing the last function, then simply point
353 * to the ftrace_stub.
354 */
355 if (rcu_dereference_protected(*list,
356 lockdep_is_held(&ftrace_lock)) == ops &&
357 rcu_dereference_protected(ops->next,
358 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
359 *list = &ftrace_list_end;
360 return 0;
361 }
362
363 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
364 if (*p == ops)
365 break;
366
367 if (*p != ops)
368 return -1;
369
370 *p = (*p)->next;
371 return 0;
372}
373
374static void ftrace_update_trampoline(struct ftrace_ops *ops);
375
376static int __register_ftrace_function(struct ftrace_ops *ops)
377{
378 if (ops->flags & FTRACE_OPS_FL_DELETED)
379 return -EINVAL;
380
381 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
382 return -EBUSY;
383
384#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
385 /*
386 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
387 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
388 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
389 */
390 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
391 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
392 return -EINVAL;
393
394 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
395 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
396#endif
397
398 if (!core_kernel_data((unsigned long)ops))
399 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
400
401 add_ftrace_ops(&ftrace_ops_list, ops);
402
403 /* Always save the function, and reset at unregistering */
404 ops->saved_func = ops->func;
405
406 if (ftrace_pids_enabled(ops))
407 ops->func = ftrace_pid_func;
408
409 ftrace_update_trampoline(ops);
410
411 if (ftrace_enabled)
412 update_ftrace_function();
413
414 return 0;
415}
416
417static int __unregister_ftrace_function(struct ftrace_ops *ops)
418{
419 int ret;
420
421 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
422 return -EBUSY;
423
424 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
425
426 if (ret < 0)
427 return ret;
428
429 if (ftrace_enabled)
430 update_ftrace_function();
431
432 ops->func = ops->saved_func;
433
434 return 0;
435}
436
437static void ftrace_update_pid_func(void)
438{
439 struct ftrace_ops *op;
440
441 /* Only do something if we are tracing something */
442 if (ftrace_trace_function == ftrace_stub)
443 return;
444
445 do_for_each_ftrace_op(op, ftrace_ops_list) {
446 if (op->flags & FTRACE_OPS_FL_PID) {
447 op->func = ftrace_pids_enabled(op) ?
448 ftrace_pid_func : op->saved_func;
449 ftrace_update_trampoline(op);
450 }
451 } while_for_each_ftrace_op(op);
452
453 update_ftrace_function();
454}
455
456#ifdef CONFIG_FUNCTION_PROFILER
457struct ftrace_profile {
458 struct hlist_node node;
459 unsigned long ip;
460 unsigned long counter;
461#ifdef CONFIG_FUNCTION_GRAPH_TRACER
462 unsigned long long time;
463 unsigned long long time_squared;
464#endif
465};
466
467struct ftrace_profile_page {
468 struct ftrace_profile_page *next;
469 unsigned long index;
470 struct ftrace_profile records[];
471};
472
473struct ftrace_profile_stat {
474 atomic_t disabled;
475 struct hlist_head *hash;
476 struct ftrace_profile_page *pages;
477 struct ftrace_profile_page *start;
478 struct tracer_stat stat;
479};
480
481#define PROFILE_RECORDS_SIZE \
482 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
483
484#define PROFILES_PER_PAGE \
485 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
486
487static int ftrace_profile_enabled __read_mostly;
488
489/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
490static DEFINE_MUTEX(ftrace_profile_lock);
491
492static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
493
494#define FTRACE_PROFILE_HASH_BITS 10
495#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
496
497static void *
498function_stat_next(void *v, int idx)
499{
500 struct ftrace_profile *rec = v;
501 struct ftrace_profile_page *pg;
502
503 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
504
505 again:
506 if (idx != 0)
507 rec++;
508
509 if ((void *)rec >= (void *)&pg->records[pg->index]) {
510 pg = pg->next;
511 if (!pg)
512 return NULL;
513 rec = &pg->records[0];
514 if (!rec->counter)
515 goto again;
516 }
517
518 return rec;
519}
520
521static void *function_stat_start(struct tracer_stat *trace)
522{
523 struct ftrace_profile_stat *stat =
524 container_of(trace, struct ftrace_profile_stat, stat);
525
526 if (!stat || !stat->start)
527 return NULL;
528
529 return function_stat_next(&stat->start->records[0], 0);
530}
531
532#ifdef CONFIG_FUNCTION_GRAPH_TRACER
533/* function graph compares on total time */
534static int function_stat_cmp(void *p1, void *p2)
535{
536 struct ftrace_profile *a = p1;
537 struct ftrace_profile *b = p2;
538
539 if (a->time < b->time)
540 return -1;
541 if (a->time > b->time)
542 return 1;
543 else
544 return 0;
545}
546#else
547/* not function graph compares against hits */
548static int function_stat_cmp(void *p1, void *p2)
549{
550 struct ftrace_profile *a = p1;
551 struct ftrace_profile *b = p2;
552
553 if (a->counter < b->counter)
554 return -1;
555 if (a->counter > b->counter)
556 return 1;
557 else
558 return 0;
559}
560#endif
561
562static int function_stat_headers(struct seq_file *m)
563{
564#ifdef CONFIG_FUNCTION_GRAPH_TRACER
565 seq_puts(m, " Function "
566 "Hit Time Avg s^2\n"
567 " -------- "
568 "--- ---- --- ---\n");
569#else
570 seq_puts(m, " Function Hit\n"
571 " -------- ---\n");
572#endif
573 return 0;
574}
575
576static int function_stat_show(struct seq_file *m, void *v)
577{
578 struct ftrace_profile *rec = v;
579 char str[KSYM_SYMBOL_LEN];
580 int ret = 0;
581#ifdef CONFIG_FUNCTION_GRAPH_TRACER
582 static struct trace_seq s;
583 unsigned long long avg;
584 unsigned long long stddev;
585#endif
586 mutex_lock(&ftrace_profile_lock);
587
588 /* we raced with function_profile_reset() */
589 if (unlikely(rec->counter == 0)) {
590 ret = -EBUSY;
591 goto out;
592 }
593
594#ifdef CONFIG_FUNCTION_GRAPH_TRACER
595 avg = rec->time;
596 do_div(avg, rec->counter);
597 if (tracing_thresh && (avg < tracing_thresh))
598 goto out;
599#endif
600
601 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
602 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
603
604#ifdef CONFIG_FUNCTION_GRAPH_TRACER
605 seq_puts(m, " ");
606
607 /* Sample standard deviation (s^2) */
608 if (rec->counter <= 1)
609 stddev = 0;
610 else {
611 /*
612 * Apply Welford's method:
613 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
614 */
615 stddev = rec->counter * rec->time_squared -
616 rec->time * rec->time;
617
618 /*
619 * Divide only 1000 for ns^2 -> us^2 conversion.
620 * trace_print_graph_duration will divide 1000 again.
621 */
622 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
623 }
624
625 trace_seq_init(&s);
626 trace_print_graph_duration(rec->time, &s);
627 trace_seq_puts(&s, " ");
628 trace_print_graph_duration(avg, &s);
629 trace_seq_puts(&s, " ");
630 trace_print_graph_duration(stddev, &s);
631 trace_print_seq(m, &s);
632#endif
633 seq_putc(m, '\n');
634out:
635 mutex_unlock(&ftrace_profile_lock);
636
637 return ret;
638}
639
640static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
641{
642 struct ftrace_profile_page *pg;
643
644 pg = stat->pages = stat->start;
645
646 while (pg) {
647 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
648 pg->index = 0;
649 pg = pg->next;
650 }
651
652 memset(stat->hash, 0,
653 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
654}
655
656int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
657{
658 struct ftrace_profile_page *pg;
659 int functions;
660 int pages;
661 int i;
662
663 /* If we already allocated, do nothing */
664 if (stat->pages)
665 return 0;
666
667 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
668 if (!stat->pages)
669 return -ENOMEM;
670
671#ifdef CONFIG_DYNAMIC_FTRACE
672 functions = ftrace_update_tot_cnt;
673#else
674 /*
675 * We do not know the number of functions that exist because
676 * dynamic tracing is what counts them. With past experience
677 * we have around 20K functions. That should be more than enough.
678 * It is highly unlikely we will execute every function in
679 * the kernel.
680 */
681 functions = 20000;
682#endif
683
684 pg = stat->start = stat->pages;
685
686 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
687
688 for (i = 1; i < pages; i++) {
689 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
690 if (!pg->next)
691 goto out_free;
692 pg = pg->next;
693 }
694
695 return 0;
696
697 out_free:
698 pg = stat->start;
699 while (pg) {
700 unsigned long tmp = (unsigned long)pg;
701
702 pg = pg->next;
703 free_page(tmp);
704 }
705
706 stat->pages = NULL;
707 stat->start = NULL;
708
709 return -ENOMEM;
710}
711
712static int ftrace_profile_init_cpu(int cpu)
713{
714 struct ftrace_profile_stat *stat;
715 int size;
716
717 stat = &per_cpu(ftrace_profile_stats, cpu);
718
719 if (stat->hash) {
720 /* If the profile is already created, simply reset it */
721 ftrace_profile_reset(stat);
722 return 0;
723 }
724
725 /*
726 * We are profiling all functions, but usually only a few thousand
727 * functions are hit. We'll make a hash of 1024 items.
728 */
729 size = FTRACE_PROFILE_HASH_SIZE;
730
731 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
732
733 if (!stat->hash)
734 return -ENOMEM;
735
736 /* Preallocate the function profiling pages */
737 if (ftrace_profile_pages_init(stat) < 0) {
738 kfree(stat->hash);
739 stat->hash = NULL;
740 return -ENOMEM;
741 }
742
743 return 0;
744}
745
746static int ftrace_profile_init(void)
747{
748 int cpu;
749 int ret = 0;
750
751 for_each_possible_cpu(cpu) {
752 ret = ftrace_profile_init_cpu(cpu);
753 if (ret)
754 break;
755 }
756
757 return ret;
758}
759
760/* interrupts must be disabled */
761static struct ftrace_profile *
762ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
763{
764 struct ftrace_profile *rec;
765 struct hlist_head *hhd;
766 unsigned long key;
767
768 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
769 hhd = &stat->hash[key];
770
771 if (hlist_empty(hhd))
772 return NULL;
773
774 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
775 if (rec->ip == ip)
776 return rec;
777 }
778
779 return NULL;
780}
781
782static void ftrace_add_profile(struct ftrace_profile_stat *stat,
783 struct ftrace_profile *rec)
784{
785 unsigned long key;
786
787 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
788 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
789}
790
791/*
792 * The memory is already allocated, this simply finds a new record to use.
793 */
794static struct ftrace_profile *
795ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
796{
797 struct ftrace_profile *rec = NULL;
798
799 /* prevent recursion (from NMIs) */
800 if (atomic_inc_return(&stat->disabled) != 1)
801 goto out;
802
803 /*
804 * Try to find the function again since an NMI
805 * could have added it
806 */
807 rec = ftrace_find_profiled_func(stat, ip);
808 if (rec)
809 goto out;
810
811 if (stat->pages->index == PROFILES_PER_PAGE) {
812 if (!stat->pages->next)
813 goto out;
814 stat->pages = stat->pages->next;
815 }
816
817 rec = &stat->pages->records[stat->pages->index++];
818 rec->ip = ip;
819 ftrace_add_profile(stat, rec);
820
821 out:
822 atomic_dec(&stat->disabled);
823
824 return rec;
825}
826
827static void
828function_profile_call(unsigned long ip, unsigned long parent_ip,
829 struct ftrace_ops *ops, struct pt_regs *regs)
830{
831 struct ftrace_profile_stat *stat;
832 struct ftrace_profile *rec;
833 unsigned long flags;
834
835 if (!ftrace_profile_enabled)
836 return;
837
838 local_irq_save(flags);
839
840 stat = this_cpu_ptr(&ftrace_profile_stats);
841 if (!stat->hash || !ftrace_profile_enabled)
842 goto out;
843
844 rec = ftrace_find_profiled_func(stat, ip);
845 if (!rec) {
846 rec = ftrace_profile_alloc(stat, ip);
847 if (!rec)
848 goto out;
849 }
850
851 rec->counter++;
852 out:
853 local_irq_restore(flags);
854}
855
856#ifdef CONFIG_FUNCTION_GRAPH_TRACER
857static int profile_graph_entry(struct ftrace_graph_ent *trace)
858{
859 int index = trace->depth;
860
861 function_profile_call(trace->func, 0, NULL, NULL);
862
863 /* If function graph is shutting down, ret_stack can be NULL */
864 if (!current->ret_stack)
865 return 0;
866
867 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
868 current->ret_stack[index].subtime = 0;
869
870 return 1;
871}
872
873static void profile_graph_return(struct ftrace_graph_ret *trace)
874{
875 struct ftrace_profile_stat *stat;
876 unsigned long long calltime;
877 struct ftrace_profile *rec;
878 unsigned long flags;
879
880 local_irq_save(flags);
881 stat = this_cpu_ptr(&ftrace_profile_stats);
882 if (!stat->hash || !ftrace_profile_enabled)
883 goto out;
884
885 /* If the calltime was zero'd ignore it */
886 if (!trace->calltime)
887 goto out;
888
889 calltime = trace->rettime - trace->calltime;
890
891 if (!fgraph_graph_time) {
892 int index;
893
894 index = trace->depth;
895
896 /* Append this call time to the parent time to subtract */
897 if (index)
898 current->ret_stack[index - 1].subtime += calltime;
899
900 if (current->ret_stack[index].subtime < calltime)
901 calltime -= current->ret_stack[index].subtime;
902 else
903 calltime = 0;
904 }
905
906 rec = ftrace_find_profiled_func(stat, trace->func);
907 if (rec) {
908 rec->time += calltime;
909 rec->time_squared += calltime * calltime;
910 }
911
912 out:
913 local_irq_restore(flags);
914}
915
916static int register_ftrace_profiler(void)
917{
918 return register_ftrace_graph(&profile_graph_return,
919 &profile_graph_entry);
920}
921
922static void unregister_ftrace_profiler(void)
923{
924 unregister_ftrace_graph();
925}
926#else
927static struct ftrace_ops ftrace_profile_ops __read_mostly = {
928 .func = function_profile_call,
929 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
930 INIT_OPS_HASH(ftrace_profile_ops)
931};
932
933static int register_ftrace_profiler(void)
934{
935 return register_ftrace_function(&ftrace_profile_ops);
936}
937
938static void unregister_ftrace_profiler(void)
939{
940 unregister_ftrace_function(&ftrace_profile_ops);
941}
942#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
943
944static ssize_t
945ftrace_profile_write(struct file *filp, const char __user *ubuf,
946 size_t cnt, loff_t *ppos)
947{
948 unsigned long val;
949 int ret;
950
951 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
952 if (ret)
953 return ret;
954
955 val = !!val;
956
957 mutex_lock(&ftrace_profile_lock);
958 if (ftrace_profile_enabled ^ val) {
959 if (val) {
960 ret = ftrace_profile_init();
961 if (ret < 0) {
962 cnt = ret;
963 goto out;
964 }
965
966 ret = register_ftrace_profiler();
967 if (ret < 0) {
968 cnt = ret;
969 goto out;
970 }
971 ftrace_profile_enabled = 1;
972 } else {
973 ftrace_profile_enabled = 0;
974 /*
975 * unregister_ftrace_profiler calls stop_machine
976 * so this acts like an synchronize_sched.
977 */
978 unregister_ftrace_profiler();
979 }
980 }
981 out:
982 mutex_unlock(&ftrace_profile_lock);
983
984 *ppos += cnt;
985
986 return cnt;
987}
988
989static ssize_t
990ftrace_profile_read(struct file *filp, char __user *ubuf,
991 size_t cnt, loff_t *ppos)
992{
993 char buf[64]; /* big enough to hold a number */
994 int r;
995
996 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
997 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
998}
999
1000static const struct file_operations ftrace_profile_fops = {
1001 .open = tracing_open_generic,
1002 .read = ftrace_profile_read,
1003 .write = ftrace_profile_write,
1004 .llseek = default_llseek,
1005};
1006
1007/* used to initialize the real stat files */
1008static struct tracer_stat function_stats __initdata = {
1009 .name = "functions",
1010 .stat_start = function_stat_start,
1011 .stat_next = function_stat_next,
1012 .stat_cmp = function_stat_cmp,
1013 .stat_headers = function_stat_headers,
1014 .stat_show = function_stat_show
1015};
1016
1017static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1018{
1019 struct ftrace_profile_stat *stat;
1020 struct dentry *entry;
1021 char *name;
1022 int ret;
1023 int cpu;
1024
1025 for_each_possible_cpu(cpu) {
1026 stat = &per_cpu(ftrace_profile_stats, cpu);
1027
1028 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1029 if (!name) {
1030 /*
1031 * The files created are permanent, if something happens
1032 * we still do not free memory.
1033 */
1034 WARN(1,
1035 "Could not allocate stat file for cpu %d\n",
1036 cpu);
1037 return;
1038 }
1039 stat->stat = function_stats;
1040 stat->stat.name = name;
1041 ret = register_stat_tracer(&stat->stat);
1042 if (ret) {
1043 WARN(1,
1044 "Could not register function stat for cpu %d\n",
1045 cpu);
1046 kfree(name);
1047 return;
1048 }
1049 }
1050
1051 entry = tracefs_create_file("function_profile_enabled", 0644,
1052 d_tracer, NULL, &ftrace_profile_fops);
1053 if (!entry)
1054 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1055}
1056
1057#else /* CONFIG_FUNCTION_PROFILER */
1058static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1059{
1060}
1061#endif /* CONFIG_FUNCTION_PROFILER */
1062
1063static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1064
1065#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1066static int ftrace_graph_active;
1067#else
1068# define ftrace_graph_active 0
1069#endif
1070
1071#ifdef CONFIG_DYNAMIC_FTRACE
1072
1073static struct ftrace_ops *removed_ops;
1074
1075/*
1076 * Set when doing a global update, like enabling all recs or disabling them.
1077 * It is not set when just updating a single ftrace_ops.
1078 */
1079static bool update_all_ops;
1080
1081#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1082# error Dynamic ftrace depends on MCOUNT_RECORD
1083#endif
1084
1085struct ftrace_func_entry {
1086 struct hlist_node hlist;
1087 unsigned long ip;
1088};
1089
1090struct ftrace_func_probe {
1091 struct ftrace_probe_ops *probe_ops;
1092 struct ftrace_ops ops;
1093 struct trace_array *tr;
1094 struct list_head list;
1095 void *data;
1096 int ref;
1097};
1098
1099/*
1100 * We make these constant because no one should touch them,
1101 * but they are used as the default "empty hash", to avoid allocating
1102 * it all the time. These are in a read only section such that if
1103 * anyone does try to modify it, it will cause an exception.
1104 */
1105static const struct hlist_head empty_buckets[1];
1106static const struct ftrace_hash empty_hash = {
1107 .buckets = (struct hlist_head *)empty_buckets,
1108};
1109#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1110
1111static struct ftrace_ops global_ops = {
1112 .func = ftrace_stub,
1113 .local_hash.notrace_hash = EMPTY_HASH,
1114 .local_hash.filter_hash = EMPTY_HASH,
1115 INIT_OPS_HASH(global_ops)
1116 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1117 FTRACE_OPS_FL_INITIALIZED |
1118 FTRACE_OPS_FL_PID,
1119};
1120
1121/*
1122 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1123 */
1124struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1125{
1126 struct ftrace_ops *op = NULL;
1127
1128 /*
1129 * Some of the ops may be dynamically allocated,
1130 * they are freed after a synchronize_sched().
1131 */
1132 preempt_disable_notrace();
1133
1134 do_for_each_ftrace_op(op, ftrace_ops_list) {
1135 /*
1136 * This is to check for dynamically allocated trampolines.
1137 * Trampolines that are in kernel text will have
1138 * core_kernel_text() return true.
1139 */
1140 if (op->trampoline && op->trampoline_size)
1141 if (addr >= op->trampoline &&
1142 addr < op->trampoline + op->trampoline_size) {
1143 preempt_enable_notrace();
1144 return op;
1145 }
1146 } while_for_each_ftrace_op(op);
1147 preempt_enable_notrace();
1148
1149 return NULL;
1150}
1151
1152/*
1153 * This is used by __kernel_text_address() to return true if the
1154 * address is on a dynamically allocated trampoline that would
1155 * not return true for either core_kernel_text() or
1156 * is_module_text_address().
1157 */
1158bool is_ftrace_trampoline(unsigned long addr)
1159{
1160 return ftrace_ops_trampoline(addr) != NULL;
1161}
1162
1163struct ftrace_page {
1164 struct ftrace_page *next;
1165 struct dyn_ftrace *records;
1166 int index;
1167 int size;
1168};
1169
1170#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1171#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1172
1173/* estimate from running different kernels */
1174#define NR_TO_INIT 10000
1175
1176static struct ftrace_page *ftrace_pages_start;
1177static struct ftrace_page *ftrace_pages;
1178
1179static __always_inline unsigned long
1180ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1181{
1182 if (hash->size_bits > 0)
1183 return hash_long(ip, hash->size_bits);
1184
1185 return 0;
1186}
1187
1188/* Only use this function if ftrace_hash_empty() has already been tested */
1189static __always_inline struct ftrace_func_entry *
1190__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1191{
1192 unsigned long key;
1193 struct ftrace_func_entry *entry;
1194 struct hlist_head *hhd;
1195
1196 key = ftrace_hash_key(hash, ip);
1197 hhd = &hash->buckets[key];
1198
1199 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1200 if (entry->ip == ip)
1201 return entry;
1202 }
1203 return NULL;
1204}
1205
1206/**
1207 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1208 * @hash: The hash to look at
1209 * @ip: The instruction pointer to test
1210 *
1211 * Search a given @hash to see if a given instruction pointer (@ip)
1212 * exists in it.
1213 *
1214 * Returns the entry that holds the @ip if found. NULL otherwise.
1215 */
1216struct ftrace_func_entry *
1217ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1218{
1219 if (ftrace_hash_empty(hash))
1220 return NULL;
1221
1222 return __ftrace_lookup_ip(hash, ip);
1223}
1224
1225static void __add_hash_entry(struct ftrace_hash *hash,
1226 struct ftrace_func_entry *entry)
1227{
1228 struct hlist_head *hhd;
1229 unsigned long key;
1230
1231 key = ftrace_hash_key(hash, entry->ip);
1232 hhd = &hash->buckets[key];
1233 hlist_add_head(&entry->hlist, hhd);
1234 hash->count++;
1235}
1236
1237static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1238{
1239 struct ftrace_func_entry *entry;
1240
1241 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1242 if (!entry)
1243 return -ENOMEM;
1244
1245 entry->ip = ip;
1246 __add_hash_entry(hash, entry);
1247
1248 return 0;
1249}
1250
1251static void
1252free_hash_entry(struct ftrace_hash *hash,
1253 struct ftrace_func_entry *entry)
1254{
1255 hlist_del(&entry->hlist);
1256 kfree(entry);
1257 hash->count--;
1258}
1259
1260static void
1261remove_hash_entry(struct ftrace_hash *hash,
1262 struct ftrace_func_entry *entry)
1263{
1264 hlist_del_rcu(&entry->hlist);
1265 hash->count--;
1266}
1267
1268static void ftrace_hash_clear(struct ftrace_hash *hash)
1269{
1270 struct hlist_head *hhd;
1271 struct hlist_node *tn;
1272 struct ftrace_func_entry *entry;
1273 int size = 1 << hash->size_bits;
1274 int i;
1275
1276 if (!hash->count)
1277 return;
1278
1279 for (i = 0; i < size; i++) {
1280 hhd = &hash->buckets[i];
1281 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1282 free_hash_entry(hash, entry);
1283 }
1284 FTRACE_WARN_ON(hash->count);
1285}
1286
1287static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1288{
1289 list_del(&ftrace_mod->list);
1290 kfree(ftrace_mod->module);
1291 kfree(ftrace_mod->func);
1292 kfree(ftrace_mod);
1293}
1294
1295static void clear_ftrace_mod_list(struct list_head *head)
1296{
1297 struct ftrace_mod_load *p, *n;
1298
1299 /* stack tracer isn't supported yet */
1300 if (!head)
1301 return;
1302
1303 mutex_lock(&ftrace_lock);
1304 list_for_each_entry_safe(p, n, head, list)
1305 free_ftrace_mod(p);
1306 mutex_unlock(&ftrace_lock);
1307}
1308
1309static void free_ftrace_hash(struct ftrace_hash *hash)
1310{
1311 if (!hash || hash == EMPTY_HASH)
1312 return;
1313 ftrace_hash_clear(hash);
1314 kfree(hash->buckets);
1315 kfree(hash);
1316}
1317
1318static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1319{
1320 struct ftrace_hash *hash;
1321
1322 hash = container_of(rcu, struct ftrace_hash, rcu);
1323 free_ftrace_hash(hash);
1324}
1325
1326static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1327{
1328 if (!hash || hash == EMPTY_HASH)
1329 return;
1330 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1331}
1332
1333void ftrace_free_filter(struct ftrace_ops *ops)
1334{
1335 ftrace_ops_init(ops);
1336 free_ftrace_hash(ops->func_hash->filter_hash);
1337 free_ftrace_hash(ops->func_hash->notrace_hash);
1338}
1339
1340static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1341{
1342 struct ftrace_hash *hash;
1343 int size;
1344
1345 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1346 if (!hash)
1347 return NULL;
1348
1349 size = 1 << size_bits;
1350 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1351
1352 if (!hash->buckets) {
1353 kfree(hash);
1354 return NULL;
1355 }
1356
1357 hash->size_bits = size_bits;
1358
1359 return hash;
1360}
1361
1362
1363static int ftrace_add_mod(struct trace_array *tr,
1364 const char *func, const char *module,
1365 int enable)
1366{
1367 struct ftrace_mod_load *ftrace_mod;
1368 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1369
1370 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1371 if (!ftrace_mod)
1372 return -ENOMEM;
1373
1374 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1375 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1376 ftrace_mod->enable = enable;
1377
1378 if (!ftrace_mod->func || !ftrace_mod->module)
1379 goto out_free;
1380
1381 list_add(&ftrace_mod->list, mod_head);
1382
1383 return 0;
1384
1385 out_free:
1386 free_ftrace_mod(ftrace_mod);
1387
1388 return -ENOMEM;
1389}
1390
1391static struct ftrace_hash *
1392alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1393{
1394 struct ftrace_func_entry *entry;
1395 struct ftrace_hash *new_hash;
1396 int size;
1397 int ret;
1398 int i;
1399
1400 new_hash = alloc_ftrace_hash(size_bits);
1401 if (!new_hash)
1402 return NULL;
1403
1404 if (hash)
1405 new_hash->flags = hash->flags;
1406
1407 /* Empty hash? */
1408 if (ftrace_hash_empty(hash))
1409 return new_hash;
1410
1411 size = 1 << hash->size_bits;
1412 for (i = 0; i < size; i++) {
1413 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1414 ret = add_hash_entry(new_hash, entry->ip);
1415 if (ret < 0)
1416 goto free_hash;
1417 }
1418 }
1419
1420 FTRACE_WARN_ON(new_hash->count != hash->count);
1421
1422 return new_hash;
1423
1424 free_hash:
1425 free_ftrace_hash(new_hash);
1426 return NULL;
1427}
1428
1429static void
1430ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1431static void
1432ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1433
1434static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1435 struct ftrace_hash *new_hash);
1436
1437static struct ftrace_hash *
1438__ftrace_hash_move(struct ftrace_hash *src)
1439{
1440 struct ftrace_func_entry *entry;
1441 struct hlist_node *tn;
1442 struct hlist_head *hhd;
1443 struct ftrace_hash *new_hash;
1444 int size = src->count;
1445 int bits = 0;
1446 int i;
1447
1448 /*
1449 * If the new source is empty, just return the empty_hash.
1450 */
1451 if (ftrace_hash_empty(src))
1452 return EMPTY_HASH;
1453
1454 /*
1455 * Make the hash size about 1/2 the # found
1456 */
1457 for (size /= 2; size; size >>= 1)
1458 bits++;
1459
1460 /* Don't allocate too much */
1461 if (bits > FTRACE_HASH_MAX_BITS)
1462 bits = FTRACE_HASH_MAX_BITS;
1463
1464 new_hash = alloc_ftrace_hash(bits);
1465 if (!new_hash)
1466 return NULL;
1467
1468 new_hash->flags = src->flags;
1469
1470 size = 1 << src->size_bits;
1471 for (i = 0; i < size; i++) {
1472 hhd = &src->buckets[i];
1473 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1474 remove_hash_entry(src, entry);
1475 __add_hash_entry(new_hash, entry);
1476 }
1477 }
1478
1479 return new_hash;
1480}
1481
1482static int
1483ftrace_hash_move(struct ftrace_ops *ops, int enable,
1484 struct ftrace_hash **dst, struct ftrace_hash *src)
1485{
1486 struct ftrace_hash *new_hash;
1487 int ret;
1488
1489 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1490 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1491 return -EINVAL;
1492
1493 new_hash = __ftrace_hash_move(src);
1494 if (!new_hash)
1495 return -ENOMEM;
1496
1497 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1498 if (enable) {
1499 /* IPMODIFY should be updated only when filter_hash updating */
1500 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1501 if (ret < 0) {
1502 free_ftrace_hash(new_hash);
1503 return ret;
1504 }
1505 }
1506
1507 /*
1508 * Remove the current set, update the hash and add
1509 * them back.
1510 */
1511 ftrace_hash_rec_disable_modify(ops, enable);
1512
1513 rcu_assign_pointer(*dst, new_hash);
1514
1515 ftrace_hash_rec_enable_modify(ops, enable);
1516
1517 return 0;
1518}
1519
1520static bool hash_contains_ip(unsigned long ip,
1521 struct ftrace_ops_hash *hash)
1522{
1523 /*
1524 * The function record is a match if it exists in the filter
1525 * hash and not in the notrace hash. Note, an emty hash is
1526 * considered a match for the filter hash, but an empty
1527 * notrace hash is considered not in the notrace hash.
1528 */
1529 return (ftrace_hash_empty(hash->filter_hash) ||
1530 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1531 (ftrace_hash_empty(hash->notrace_hash) ||
1532 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1533}
1534
1535/*
1536 * Test the hashes for this ops to see if we want to call
1537 * the ops->func or not.
1538 *
1539 * It's a match if the ip is in the ops->filter_hash or
1540 * the filter_hash does not exist or is empty,
1541 * AND
1542 * the ip is not in the ops->notrace_hash.
1543 *
1544 * This needs to be called with preemption disabled as
1545 * the hashes are freed with call_rcu_sched().
1546 */
1547static int
1548ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1549{
1550 struct ftrace_ops_hash hash;
1551 int ret;
1552
1553#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1554 /*
1555 * There's a small race when adding ops that the ftrace handler
1556 * that wants regs, may be called without them. We can not
1557 * allow that handler to be called if regs is NULL.
1558 */
1559 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1560 return 0;
1561#endif
1562
1563 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1564 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1565
1566 if (hash_contains_ip(ip, &hash))
1567 ret = 1;
1568 else
1569 ret = 0;
1570
1571 return ret;
1572}
1573
1574/*
1575 * This is a double for. Do not use 'break' to break out of the loop,
1576 * you must use a goto.
1577 */
1578#define do_for_each_ftrace_rec(pg, rec) \
1579 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1580 int _____i; \
1581 for (_____i = 0; _____i < pg->index; _____i++) { \
1582 rec = &pg->records[_____i];
1583
1584#define while_for_each_ftrace_rec() \
1585 } \
1586 }
1587
1588
1589static int ftrace_cmp_recs(const void *a, const void *b)
1590{
1591 const struct dyn_ftrace *key = a;
1592 const struct dyn_ftrace *rec = b;
1593
1594 if (key->flags < rec->ip)
1595 return -1;
1596 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1597 return 1;
1598 return 0;
1599}
1600
1601/**
1602 * ftrace_location_range - return the first address of a traced location
1603 * if it touches the given ip range
1604 * @start: start of range to search.
1605 * @end: end of range to search (inclusive). @end points to the last byte
1606 * to check.
1607 *
1608 * Returns rec->ip if the related ftrace location is a least partly within
1609 * the given address range. That is, the first address of the instruction
1610 * that is either a NOP or call to the function tracer. It checks the ftrace
1611 * internal tables to determine if the address belongs or not.
1612 */
1613unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1614{
1615 struct ftrace_page *pg;
1616 struct dyn_ftrace *rec;
1617 struct dyn_ftrace key;
1618
1619 key.ip = start;
1620 key.flags = end; /* overload flags, as it is unsigned long */
1621
1622 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1623 if (end < pg->records[0].ip ||
1624 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1625 continue;
1626 rec = bsearch(&key, pg->records, pg->index,
1627 sizeof(struct dyn_ftrace),
1628 ftrace_cmp_recs);
1629 if (rec)
1630 return rec->ip;
1631 }
1632
1633 return 0;
1634}
1635
1636/**
1637 * ftrace_location - return true if the ip giving is a traced location
1638 * @ip: the instruction pointer to check
1639 *
1640 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1641 * That is, the instruction that is either a NOP or call to
1642 * the function tracer. It checks the ftrace internal tables to
1643 * determine if the address belongs or not.
1644 */
1645unsigned long ftrace_location(unsigned long ip)
1646{
1647 return ftrace_location_range(ip, ip);
1648}
1649
1650/**
1651 * ftrace_text_reserved - return true if range contains an ftrace location
1652 * @start: start of range to search
1653 * @end: end of range to search (inclusive). @end points to the last byte to check.
1654 *
1655 * Returns 1 if @start and @end contains a ftrace location.
1656 * That is, the instruction that is either a NOP or call to
1657 * the function tracer. It checks the ftrace internal tables to
1658 * determine if the address belongs or not.
1659 */
1660int ftrace_text_reserved(const void *start, const void *end)
1661{
1662 unsigned long ret;
1663
1664 ret = ftrace_location_range((unsigned long)start,
1665 (unsigned long)end);
1666
1667 return (int)!!ret;
1668}
1669
1670/* Test if ops registered to this rec needs regs */
1671static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1672{
1673 struct ftrace_ops *ops;
1674 bool keep_regs = false;
1675
1676 for (ops = ftrace_ops_list;
1677 ops != &ftrace_list_end; ops = ops->next) {
1678 /* pass rec in as regs to have non-NULL val */
1679 if (ftrace_ops_test(ops, rec->ip, rec)) {
1680 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1681 keep_regs = true;
1682 break;
1683 }
1684 }
1685 }
1686
1687 return keep_regs;
1688}
1689
1690static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1691 int filter_hash,
1692 bool inc)
1693{
1694 struct ftrace_hash *hash;
1695 struct ftrace_hash *other_hash;
1696 struct ftrace_page *pg;
1697 struct dyn_ftrace *rec;
1698 bool update = false;
1699 int count = 0;
1700 int all = false;
1701
1702 /* Only update if the ops has been registered */
1703 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1704 return false;
1705
1706 /*
1707 * In the filter_hash case:
1708 * If the count is zero, we update all records.
1709 * Otherwise we just update the items in the hash.
1710 *
1711 * In the notrace_hash case:
1712 * We enable the update in the hash.
1713 * As disabling notrace means enabling the tracing,
1714 * and enabling notrace means disabling, the inc variable
1715 * gets inversed.
1716 */
1717 if (filter_hash) {
1718 hash = ops->func_hash->filter_hash;
1719 other_hash = ops->func_hash->notrace_hash;
1720 if (ftrace_hash_empty(hash))
1721 all = true;
1722 } else {
1723 inc = !inc;
1724 hash = ops->func_hash->notrace_hash;
1725 other_hash = ops->func_hash->filter_hash;
1726 /*
1727 * If the notrace hash has no items,
1728 * then there's nothing to do.
1729 */
1730 if (ftrace_hash_empty(hash))
1731 return false;
1732 }
1733
1734 do_for_each_ftrace_rec(pg, rec) {
1735 int in_other_hash = 0;
1736 int in_hash = 0;
1737 int match = 0;
1738
1739 if (rec->flags & FTRACE_FL_DISABLED)
1740 continue;
1741
1742 if (all) {
1743 /*
1744 * Only the filter_hash affects all records.
1745 * Update if the record is not in the notrace hash.
1746 */
1747 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1748 match = 1;
1749 } else {
1750 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1751 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1752
1753 /*
1754 * If filter_hash is set, we want to match all functions
1755 * that are in the hash but not in the other hash.
1756 *
1757 * If filter_hash is not set, then we are decrementing.
1758 * That means we match anything that is in the hash
1759 * and also in the other_hash. That is, we need to turn
1760 * off functions in the other hash because they are disabled
1761 * by this hash.
1762 */
1763 if (filter_hash && in_hash && !in_other_hash)
1764 match = 1;
1765 else if (!filter_hash && in_hash &&
1766 (in_other_hash || ftrace_hash_empty(other_hash)))
1767 match = 1;
1768 }
1769 if (!match)
1770 continue;
1771
1772 if (inc) {
1773 rec->flags++;
1774 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1775 return false;
1776
1777 /*
1778 * If there's only a single callback registered to a
1779 * function, and the ops has a trampoline registered
1780 * for it, then we can call it directly.
1781 */
1782 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1783 rec->flags |= FTRACE_FL_TRAMP;
1784 else
1785 /*
1786 * If we are adding another function callback
1787 * to this function, and the previous had a
1788 * custom trampoline in use, then we need to go
1789 * back to the default trampoline.
1790 */
1791 rec->flags &= ~FTRACE_FL_TRAMP;
1792
1793 /*
1794 * If any ops wants regs saved for this function
1795 * then all ops will get saved regs.
1796 */
1797 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1798 rec->flags |= FTRACE_FL_REGS;
1799 } else {
1800 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1801 return false;
1802 rec->flags--;
1803
1804 /*
1805 * If the rec had REGS enabled and the ops that is
1806 * being removed had REGS set, then see if there is
1807 * still any ops for this record that wants regs.
1808 * If not, we can stop recording them.
1809 */
1810 if (ftrace_rec_count(rec) > 0 &&
1811 rec->flags & FTRACE_FL_REGS &&
1812 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1813 if (!test_rec_ops_needs_regs(rec))
1814 rec->flags &= ~FTRACE_FL_REGS;
1815 }
1816
1817 /*
1818 * If the rec had TRAMP enabled, then it needs to
1819 * be cleared. As TRAMP can only be enabled iff
1820 * there is only a single ops attached to it.
1821 * In otherwords, always disable it on decrementing.
1822 * In the future, we may set it if rec count is
1823 * decremented to one, and the ops that is left
1824 * has a trampoline.
1825 */
1826 rec->flags &= ~FTRACE_FL_TRAMP;
1827
1828 /*
1829 * flags will be cleared in ftrace_check_record()
1830 * if rec count is zero.
1831 */
1832 }
1833 count++;
1834
1835 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1836 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1837
1838 /* Shortcut, if we handled all records, we are done. */
1839 if (!all && count == hash->count)
1840 return update;
1841 } while_for_each_ftrace_rec();
1842
1843 return update;
1844}
1845
1846static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1847 int filter_hash)
1848{
1849 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1850}
1851
1852static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1853 int filter_hash)
1854{
1855 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1856}
1857
1858static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1859 int filter_hash, int inc)
1860{
1861 struct ftrace_ops *op;
1862
1863 __ftrace_hash_rec_update(ops, filter_hash, inc);
1864
1865 if (ops->func_hash != &global_ops.local_hash)
1866 return;
1867
1868 /*
1869 * If the ops shares the global_ops hash, then we need to update
1870 * all ops that are enabled and use this hash.
1871 */
1872 do_for_each_ftrace_op(op, ftrace_ops_list) {
1873 /* Already done */
1874 if (op == ops)
1875 continue;
1876 if (op->func_hash == &global_ops.local_hash)
1877 __ftrace_hash_rec_update(op, filter_hash, inc);
1878 } while_for_each_ftrace_op(op);
1879}
1880
1881static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1882 int filter_hash)
1883{
1884 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1885}
1886
1887static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1888 int filter_hash)
1889{
1890 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1891}
1892
1893/*
1894 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1895 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1896 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1897 * Note that old_hash and new_hash has below meanings
1898 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1899 * - If the hash is EMPTY_HASH, it hits nothing
1900 * - Anything else hits the recs which match the hash entries.
1901 */
1902static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1903 struct ftrace_hash *old_hash,
1904 struct ftrace_hash *new_hash)
1905{
1906 struct ftrace_page *pg;
1907 struct dyn_ftrace *rec, *end = NULL;
1908 int in_old, in_new;
1909
1910 /* Only update if the ops has been registered */
1911 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1912 return 0;
1913
1914 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1915 return 0;
1916
1917 /*
1918 * Since the IPMODIFY is a very address sensitive action, we do not
1919 * allow ftrace_ops to set all functions to new hash.
1920 */
1921 if (!new_hash || !old_hash)
1922 return -EINVAL;
1923
1924 /* Update rec->flags */
1925 do_for_each_ftrace_rec(pg, rec) {
1926
1927 if (rec->flags & FTRACE_FL_DISABLED)
1928 continue;
1929
1930 /* We need to update only differences of filter_hash */
1931 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1932 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1933 if (in_old == in_new)
1934 continue;
1935
1936 if (in_new) {
1937 /* New entries must ensure no others are using it */
1938 if (rec->flags & FTRACE_FL_IPMODIFY)
1939 goto rollback;
1940 rec->flags |= FTRACE_FL_IPMODIFY;
1941 } else /* Removed entry */
1942 rec->flags &= ~FTRACE_FL_IPMODIFY;
1943 } while_for_each_ftrace_rec();
1944
1945 return 0;
1946
1947rollback:
1948 end = rec;
1949
1950 /* Roll back what we did above */
1951 do_for_each_ftrace_rec(pg, rec) {
1952
1953 if (rec->flags & FTRACE_FL_DISABLED)
1954 continue;
1955
1956 if (rec == end)
1957 goto err_out;
1958
1959 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1960 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1961 if (in_old == in_new)
1962 continue;
1963
1964 if (in_new)
1965 rec->flags &= ~FTRACE_FL_IPMODIFY;
1966 else
1967 rec->flags |= FTRACE_FL_IPMODIFY;
1968 } while_for_each_ftrace_rec();
1969
1970err_out:
1971 return -EBUSY;
1972}
1973
1974static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1975{
1976 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1977
1978 if (ftrace_hash_empty(hash))
1979 hash = NULL;
1980
1981 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1982}
1983
1984/* Disabling always succeeds */
1985static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1986{
1987 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1988
1989 if (ftrace_hash_empty(hash))
1990 hash = NULL;
1991
1992 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1993}
1994
1995static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1996 struct ftrace_hash *new_hash)
1997{
1998 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1999
2000 if (ftrace_hash_empty(old_hash))
2001 old_hash = NULL;
2002
2003 if (ftrace_hash_empty(new_hash))
2004 new_hash = NULL;
2005
2006 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2007}
2008
2009static void print_ip_ins(const char *fmt, const unsigned char *p)
2010{
2011 int i;
2012
2013 printk(KERN_CONT "%s", fmt);
2014
2015 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
2016 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
2017}
2018
2019static struct ftrace_ops *
2020ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
2021static struct ftrace_ops *
2022ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
2023
2024enum ftrace_bug_type ftrace_bug_type;
2025const void *ftrace_expected;
2026
2027static void print_bug_type(void)
2028{
2029 switch (ftrace_bug_type) {
2030 case FTRACE_BUG_UNKNOWN:
2031 break;
2032 case FTRACE_BUG_INIT:
2033 pr_info("Initializing ftrace call sites\n");
2034 break;
2035 case FTRACE_BUG_NOP:
2036 pr_info("Setting ftrace call site to NOP\n");
2037 break;
2038 case FTRACE_BUG_CALL:
2039 pr_info("Setting ftrace call site to call ftrace function\n");
2040 break;
2041 case FTRACE_BUG_UPDATE:
2042 pr_info("Updating ftrace call site to call a different ftrace function\n");
2043 break;
2044 }
2045}
2046
2047/**
2048 * ftrace_bug - report and shutdown function tracer
2049 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2050 * @rec: The record that failed
2051 *
2052 * The arch code that enables or disables the function tracing
2053 * can call ftrace_bug() when it has detected a problem in
2054 * modifying the code. @failed should be one of either:
2055 * EFAULT - if the problem happens on reading the @ip address
2056 * EINVAL - if what is read at @ip is not what was expected
2057 * EPERM - if the problem happens on writting to the @ip address
2058 */
2059void ftrace_bug(int failed, struct dyn_ftrace *rec)
2060{
2061 unsigned long ip = rec ? rec->ip : 0;
2062
2063 switch (failed) {
2064 case -EFAULT:
2065 FTRACE_WARN_ON_ONCE(1);
2066 pr_info("ftrace faulted on modifying ");
2067 print_ip_sym(ip);
2068 break;
2069 case -EINVAL:
2070 FTRACE_WARN_ON_ONCE(1);
2071 pr_info("ftrace failed to modify ");
2072 print_ip_sym(ip);
2073 print_ip_ins(" actual: ", (unsigned char *)ip);
2074 pr_cont("\n");
2075 if (ftrace_expected) {
2076 print_ip_ins(" expected: ", ftrace_expected);
2077 pr_cont("\n");
2078 }
2079 break;
2080 case -EPERM:
2081 FTRACE_WARN_ON_ONCE(1);
2082 pr_info("ftrace faulted on writing ");
2083 print_ip_sym(ip);
2084 break;
2085 default:
2086 FTRACE_WARN_ON_ONCE(1);
2087 pr_info("ftrace faulted on unknown error ");
2088 print_ip_sym(ip);
2089 }
2090 print_bug_type();
2091 if (rec) {
2092 struct ftrace_ops *ops = NULL;
2093
2094 pr_info("ftrace record flags: %lx\n", rec->flags);
2095 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2096 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2097 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2098 ops = ftrace_find_tramp_ops_any(rec);
2099 if (ops) {
2100 do {
2101 pr_cont("\ttramp: %pS (%pS)",
2102 (void *)ops->trampoline,
2103 (void *)ops->func);
2104 ops = ftrace_find_tramp_ops_next(rec, ops);
2105 } while (ops);
2106 } else
2107 pr_cont("\ttramp: ERROR!");
2108
2109 }
2110 ip = ftrace_get_addr_curr(rec);
2111 pr_cont("\n expected tramp: %lx\n", ip);
2112 }
2113}
2114
2115static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2116{
2117 unsigned long flag = 0UL;
2118
2119 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2120
2121 if (rec->flags & FTRACE_FL_DISABLED)
2122 return FTRACE_UPDATE_IGNORE;
2123
2124 /*
2125 * If we are updating calls:
2126 *
2127 * If the record has a ref count, then we need to enable it
2128 * because someone is using it.
2129 *
2130 * Otherwise we make sure its disabled.
2131 *
2132 * If we are disabling calls, then disable all records that
2133 * are enabled.
2134 */
2135 if (enable && ftrace_rec_count(rec))
2136 flag = FTRACE_FL_ENABLED;
2137
2138 /*
2139 * If enabling and the REGS flag does not match the REGS_EN, or
2140 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2141 * this record. Set flags to fail the compare against ENABLED.
2142 */
2143 if (flag) {
2144 if (!(rec->flags & FTRACE_FL_REGS) !=
2145 !(rec->flags & FTRACE_FL_REGS_EN))
2146 flag |= FTRACE_FL_REGS;
2147
2148 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2149 !(rec->flags & FTRACE_FL_TRAMP_EN))
2150 flag |= FTRACE_FL_TRAMP;
2151 }
2152
2153 /* If the state of this record hasn't changed, then do nothing */
2154 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2155 return FTRACE_UPDATE_IGNORE;
2156
2157 if (flag) {
2158 /* Save off if rec is being enabled (for return value) */
2159 flag ^= rec->flags & FTRACE_FL_ENABLED;
2160
2161 if (update) {
2162 rec->flags |= FTRACE_FL_ENABLED;
2163 if (flag & FTRACE_FL_REGS) {
2164 if (rec->flags & FTRACE_FL_REGS)
2165 rec->flags |= FTRACE_FL_REGS_EN;
2166 else
2167 rec->flags &= ~FTRACE_FL_REGS_EN;
2168 }
2169 if (flag & FTRACE_FL_TRAMP) {
2170 if (rec->flags & FTRACE_FL_TRAMP)
2171 rec->flags |= FTRACE_FL_TRAMP_EN;
2172 else
2173 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2174 }
2175 }
2176
2177 /*
2178 * If this record is being updated from a nop, then
2179 * return UPDATE_MAKE_CALL.
2180 * Otherwise,
2181 * return UPDATE_MODIFY_CALL to tell the caller to convert
2182 * from the save regs, to a non-save regs function or
2183 * vice versa, or from a trampoline call.
2184 */
2185 if (flag & FTRACE_FL_ENABLED) {
2186 ftrace_bug_type = FTRACE_BUG_CALL;
2187 return FTRACE_UPDATE_MAKE_CALL;
2188 }
2189
2190 ftrace_bug_type = FTRACE_BUG_UPDATE;
2191 return FTRACE_UPDATE_MODIFY_CALL;
2192 }
2193
2194 if (update) {
2195 /* If there's no more users, clear all flags */
2196 if (!ftrace_rec_count(rec))
2197 rec->flags = 0;
2198 else
2199 /*
2200 * Just disable the record, but keep the ops TRAMP
2201 * and REGS states. The _EN flags must be disabled though.
2202 */
2203 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2204 FTRACE_FL_REGS_EN);
2205 }
2206
2207 ftrace_bug_type = FTRACE_BUG_NOP;
2208 return FTRACE_UPDATE_MAKE_NOP;
2209}
2210
2211/**
2212 * ftrace_update_record, set a record that now is tracing or not
2213 * @rec: the record to update
2214 * @enable: set to 1 if the record is tracing, zero to force disable
2215 *
2216 * The records that represent all functions that can be traced need
2217 * to be updated when tracing has been enabled.
2218 */
2219int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2220{
2221 return ftrace_check_record(rec, enable, 1);
2222}
2223
2224/**
2225 * ftrace_test_record, check if the record has been enabled or not
2226 * @rec: the record to test
2227 * @enable: set to 1 to check if enabled, 0 if it is disabled
2228 *
2229 * The arch code may need to test if a record is already set to
2230 * tracing to determine how to modify the function code that it
2231 * represents.
2232 */
2233int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2234{
2235 return ftrace_check_record(rec, enable, 0);
2236}
2237
2238static struct ftrace_ops *
2239ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2240{
2241 struct ftrace_ops *op;
2242 unsigned long ip = rec->ip;
2243
2244 do_for_each_ftrace_op(op, ftrace_ops_list) {
2245
2246 if (!op->trampoline)
2247 continue;
2248
2249 if (hash_contains_ip(ip, op->func_hash))
2250 return op;
2251 } while_for_each_ftrace_op(op);
2252
2253 return NULL;
2254}
2255
2256static struct ftrace_ops *
2257ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2258 struct ftrace_ops *op)
2259{
2260 unsigned long ip = rec->ip;
2261
2262 while_for_each_ftrace_op(op) {
2263
2264 if (!op->trampoline)
2265 continue;
2266
2267 if (hash_contains_ip(ip, op->func_hash))
2268 return op;
2269 }
2270
2271 return NULL;
2272}
2273
2274static struct ftrace_ops *
2275ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2276{
2277 struct ftrace_ops *op;
2278 unsigned long ip = rec->ip;
2279
2280 /*
2281 * Need to check removed ops first.
2282 * If they are being removed, and this rec has a tramp,
2283 * and this rec is in the ops list, then it would be the
2284 * one with the tramp.
2285 */
2286 if (removed_ops) {
2287 if (hash_contains_ip(ip, &removed_ops->old_hash))
2288 return removed_ops;
2289 }
2290
2291 /*
2292 * Need to find the current trampoline for a rec.
2293 * Now, a trampoline is only attached to a rec if there
2294 * was a single 'ops' attached to it. But this can be called
2295 * when we are adding another op to the rec or removing the
2296 * current one. Thus, if the op is being added, we can
2297 * ignore it because it hasn't attached itself to the rec
2298 * yet.
2299 *
2300 * If an ops is being modified (hooking to different functions)
2301 * then we don't care about the new functions that are being
2302 * added, just the old ones (that are probably being removed).
2303 *
2304 * If we are adding an ops to a function that already is using
2305 * a trampoline, it needs to be removed (trampolines are only
2306 * for single ops connected), then an ops that is not being
2307 * modified also needs to be checked.
2308 */
2309 do_for_each_ftrace_op(op, ftrace_ops_list) {
2310
2311 if (!op->trampoline)
2312 continue;
2313
2314 /*
2315 * If the ops is being added, it hasn't gotten to
2316 * the point to be removed from this tree yet.
2317 */
2318 if (op->flags & FTRACE_OPS_FL_ADDING)
2319 continue;
2320
2321
2322 /*
2323 * If the ops is being modified and is in the old
2324 * hash, then it is probably being removed from this
2325 * function.
2326 */
2327 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2328 hash_contains_ip(ip, &op->old_hash))
2329 return op;
2330 /*
2331 * If the ops is not being added or modified, and it's
2332 * in its normal filter hash, then this must be the one
2333 * we want!
2334 */
2335 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2336 hash_contains_ip(ip, op->func_hash))
2337 return op;
2338
2339 } while_for_each_ftrace_op(op);
2340
2341 return NULL;
2342}
2343
2344static struct ftrace_ops *
2345ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2346{
2347 struct ftrace_ops *op;
2348 unsigned long ip = rec->ip;
2349
2350 do_for_each_ftrace_op(op, ftrace_ops_list) {
2351 /* pass rec in as regs to have non-NULL val */
2352 if (hash_contains_ip(ip, op->func_hash))
2353 return op;
2354 } while_for_each_ftrace_op(op);
2355
2356 return NULL;
2357}
2358
2359/**
2360 * ftrace_get_addr_new - Get the call address to set to
2361 * @rec: The ftrace record descriptor
2362 *
2363 * If the record has the FTRACE_FL_REGS set, that means that it
2364 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2365 * is not not set, then it wants to convert to the normal callback.
2366 *
2367 * Returns the address of the trampoline to set to
2368 */
2369unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2370{
2371 struct ftrace_ops *ops;
2372
2373 /* Trampolines take precedence over regs */
2374 if (rec->flags & FTRACE_FL_TRAMP) {
2375 ops = ftrace_find_tramp_ops_new(rec);
2376 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2377 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2378 (void *)rec->ip, (void *)rec->ip, rec->flags);
2379 /* Ftrace is shutting down, return anything */
2380 return (unsigned long)FTRACE_ADDR;
2381 }
2382 return ops->trampoline;
2383 }
2384
2385 if (rec->flags & FTRACE_FL_REGS)
2386 return (unsigned long)FTRACE_REGS_ADDR;
2387 else
2388 return (unsigned long)FTRACE_ADDR;
2389}
2390
2391/**
2392 * ftrace_get_addr_curr - Get the call address that is already there
2393 * @rec: The ftrace record descriptor
2394 *
2395 * The FTRACE_FL_REGS_EN is set when the record already points to
2396 * a function that saves all the regs. Basically the '_EN' version
2397 * represents the current state of the function.
2398 *
2399 * Returns the address of the trampoline that is currently being called
2400 */
2401unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2402{
2403 struct ftrace_ops *ops;
2404
2405 /* Trampolines take precedence over regs */
2406 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2407 ops = ftrace_find_tramp_ops_curr(rec);
2408 if (FTRACE_WARN_ON(!ops)) {
2409 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2410 (void *)rec->ip, (void *)rec->ip);
2411 /* Ftrace is shutting down, return anything */
2412 return (unsigned long)FTRACE_ADDR;
2413 }
2414 return ops->trampoline;
2415 }
2416
2417 if (rec->flags & FTRACE_FL_REGS_EN)
2418 return (unsigned long)FTRACE_REGS_ADDR;
2419 else
2420 return (unsigned long)FTRACE_ADDR;
2421}
2422
2423static int
2424__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2425{
2426 unsigned long ftrace_old_addr;
2427 unsigned long ftrace_addr;
2428 int ret;
2429
2430 ftrace_addr = ftrace_get_addr_new(rec);
2431
2432 /* This needs to be done before we call ftrace_update_record */
2433 ftrace_old_addr = ftrace_get_addr_curr(rec);
2434
2435 ret = ftrace_update_record(rec, enable);
2436
2437 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2438
2439 switch (ret) {
2440 case FTRACE_UPDATE_IGNORE:
2441 return 0;
2442
2443 case FTRACE_UPDATE_MAKE_CALL:
2444 ftrace_bug_type = FTRACE_BUG_CALL;
2445 return ftrace_make_call(rec, ftrace_addr);
2446
2447 case FTRACE_UPDATE_MAKE_NOP:
2448 ftrace_bug_type = FTRACE_BUG_NOP;
2449 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2450
2451 case FTRACE_UPDATE_MODIFY_CALL:
2452 ftrace_bug_type = FTRACE_BUG_UPDATE;
2453 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2454 }
2455
2456 return -1; /* unknow ftrace bug */
2457}
2458
2459void __weak ftrace_replace_code(int enable)
2460{
2461 struct dyn_ftrace *rec;
2462 struct ftrace_page *pg;
2463 int failed;
2464
2465 if (unlikely(ftrace_disabled))
2466 return;
2467
2468 do_for_each_ftrace_rec(pg, rec) {
2469
2470 if (rec->flags & FTRACE_FL_DISABLED)
2471 continue;
2472
2473 failed = __ftrace_replace_code(rec, enable);
2474 if (failed) {
2475 ftrace_bug(failed, rec);
2476 /* Stop processing */
2477 return;
2478 }
2479 } while_for_each_ftrace_rec();
2480}
2481
2482struct ftrace_rec_iter {
2483 struct ftrace_page *pg;
2484 int index;
2485};
2486
2487/**
2488 * ftrace_rec_iter_start, start up iterating over traced functions
2489 *
2490 * Returns an iterator handle that is used to iterate over all
2491 * the records that represent address locations where functions
2492 * are traced.
2493 *
2494 * May return NULL if no records are available.
2495 */
2496struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2497{
2498 /*
2499 * We only use a single iterator.
2500 * Protected by the ftrace_lock mutex.
2501 */
2502 static struct ftrace_rec_iter ftrace_rec_iter;
2503 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2504
2505 iter->pg = ftrace_pages_start;
2506 iter->index = 0;
2507
2508 /* Could have empty pages */
2509 while (iter->pg && !iter->pg->index)
2510 iter->pg = iter->pg->next;
2511
2512 if (!iter->pg)
2513 return NULL;
2514
2515 return iter;
2516}
2517
2518/**
2519 * ftrace_rec_iter_next, get the next record to process.
2520 * @iter: The handle to the iterator.
2521 *
2522 * Returns the next iterator after the given iterator @iter.
2523 */
2524struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2525{
2526 iter->index++;
2527
2528 if (iter->index >= iter->pg->index) {
2529 iter->pg = iter->pg->next;
2530 iter->index = 0;
2531
2532 /* Could have empty pages */
2533 while (iter->pg && !iter->pg->index)
2534 iter->pg = iter->pg->next;
2535 }
2536
2537 if (!iter->pg)
2538 return NULL;
2539
2540 return iter;
2541}
2542
2543/**
2544 * ftrace_rec_iter_record, get the record at the iterator location
2545 * @iter: The current iterator location
2546 *
2547 * Returns the record that the current @iter is at.
2548 */
2549struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2550{
2551 return &iter->pg->records[iter->index];
2552}
2553
2554static int
2555ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2556{
2557 int ret;
2558
2559 if (unlikely(ftrace_disabled))
2560 return 0;
2561
2562 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2563 if (ret) {
2564 ftrace_bug_type = FTRACE_BUG_INIT;
2565 ftrace_bug(ret, rec);
2566 return 0;
2567 }
2568 return 1;
2569}
2570
2571/*
2572 * archs can override this function if they must do something
2573 * before the modifying code is performed.
2574 */
2575int __weak ftrace_arch_code_modify_prepare(void)
2576{
2577 return 0;
2578}
2579
2580/*
2581 * archs can override this function if they must do something
2582 * after the modifying code is performed.
2583 */
2584int __weak ftrace_arch_code_modify_post_process(void)
2585{
2586 return 0;
2587}
2588
2589void ftrace_modify_all_code(int command)
2590{
2591 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2592 int err = 0;
2593
2594 /*
2595 * If the ftrace_caller calls a ftrace_ops func directly,
2596 * we need to make sure that it only traces functions it
2597 * expects to trace. When doing the switch of functions,
2598 * we need to update to the ftrace_ops_list_func first
2599 * before the transition between old and new calls are set,
2600 * as the ftrace_ops_list_func will check the ops hashes
2601 * to make sure the ops are having the right functions
2602 * traced.
2603 */
2604 if (update) {
2605 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2606 if (FTRACE_WARN_ON(err))
2607 return;
2608 }
2609
2610 if (command & FTRACE_UPDATE_CALLS)
2611 ftrace_replace_code(1);
2612 else if (command & FTRACE_DISABLE_CALLS)
2613 ftrace_replace_code(0);
2614
2615 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2616 function_trace_op = set_function_trace_op;
2617 smp_wmb();
2618 /* If irqs are disabled, we are in stop machine */
2619 if (!irqs_disabled())
2620 smp_call_function(ftrace_sync_ipi, NULL, 1);
2621 err = ftrace_update_ftrace_func(ftrace_trace_function);
2622 if (FTRACE_WARN_ON(err))
2623 return;
2624 }
2625
2626 if (command & FTRACE_START_FUNC_RET)
2627 err = ftrace_enable_ftrace_graph_caller();
2628 else if (command & FTRACE_STOP_FUNC_RET)
2629 err = ftrace_disable_ftrace_graph_caller();
2630 FTRACE_WARN_ON(err);
2631}
2632
2633static int __ftrace_modify_code(void *data)
2634{
2635 int *command = data;
2636
2637 ftrace_modify_all_code(*command);
2638
2639 return 0;
2640}
2641
2642/**
2643 * ftrace_run_stop_machine, go back to the stop machine method
2644 * @command: The command to tell ftrace what to do
2645 *
2646 * If an arch needs to fall back to the stop machine method, the
2647 * it can call this function.
2648 */
2649void ftrace_run_stop_machine(int command)
2650{
2651 stop_machine(__ftrace_modify_code, &command, NULL);
2652}
2653
2654/**
2655 * arch_ftrace_update_code, modify the code to trace or not trace
2656 * @command: The command that needs to be done
2657 *
2658 * Archs can override this function if it does not need to
2659 * run stop_machine() to modify code.
2660 */
2661void __weak arch_ftrace_update_code(int command)
2662{
2663 ftrace_run_stop_machine(command);
2664}
2665
2666static void ftrace_run_update_code(int command)
2667{
2668 int ret;
2669
2670 ret = ftrace_arch_code_modify_prepare();
2671 FTRACE_WARN_ON(ret);
2672 if (ret)
2673 return;
2674
2675 /*
2676 * By default we use stop_machine() to modify the code.
2677 * But archs can do what ever they want as long as it
2678 * is safe. The stop_machine() is the safest, but also
2679 * produces the most overhead.
2680 */
2681 arch_ftrace_update_code(command);
2682
2683 ret = ftrace_arch_code_modify_post_process();
2684 FTRACE_WARN_ON(ret);
2685}
2686
2687static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2688 struct ftrace_ops_hash *old_hash)
2689{
2690 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2691 ops->old_hash.filter_hash = old_hash->filter_hash;
2692 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2693 ftrace_run_update_code(command);
2694 ops->old_hash.filter_hash = NULL;
2695 ops->old_hash.notrace_hash = NULL;
2696 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2697}
2698
2699static ftrace_func_t saved_ftrace_func;
2700static int ftrace_start_up;
2701
2702void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2703{
2704}
2705
2706static void ftrace_startup_enable(int command)
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 return;
2715
2716 ftrace_run_update_code(command);
2717}
2718
2719static void ftrace_startup_all(int command)
2720{
2721 update_all_ops = true;
2722 ftrace_startup_enable(command);
2723 update_all_ops = false;
2724}
2725
2726static int ftrace_startup(struct ftrace_ops *ops, int command)
2727{
2728 int ret;
2729
2730 if (unlikely(ftrace_disabled))
2731 return -ENODEV;
2732
2733 ret = __register_ftrace_function(ops);
2734 if (ret)
2735 return ret;
2736
2737 ftrace_start_up++;
2738
2739 /*
2740 * Note that ftrace probes uses this to start up
2741 * and modify functions it will probe. But we still
2742 * set the ADDING flag for modification, as probes
2743 * do not have trampolines. If they add them in the
2744 * future, then the probes will need to distinguish
2745 * between adding and updating probes.
2746 */
2747 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2748
2749 ret = ftrace_hash_ipmodify_enable(ops);
2750 if (ret < 0) {
2751 /* Rollback registration process */
2752 __unregister_ftrace_function(ops);
2753 ftrace_start_up--;
2754 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2755 return ret;
2756 }
2757
2758 if (ftrace_hash_rec_enable(ops, 1))
2759 command |= FTRACE_UPDATE_CALLS;
2760
2761 ftrace_startup_enable(command);
2762
2763 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2764
2765 return 0;
2766}
2767
2768static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2769{
2770 int ret;
2771
2772 if (unlikely(ftrace_disabled))
2773 return -ENODEV;
2774
2775 ret = __unregister_ftrace_function(ops);
2776 if (ret)
2777 return ret;
2778
2779 ftrace_start_up--;
2780 /*
2781 * Just warn in case of unbalance, no need to kill ftrace, it's not
2782 * critical but the ftrace_call callers may be never nopped again after
2783 * further ftrace uses.
2784 */
2785 WARN_ON_ONCE(ftrace_start_up < 0);
2786
2787 /* Disabling ipmodify never fails */
2788 ftrace_hash_ipmodify_disable(ops);
2789
2790 if (ftrace_hash_rec_disable(ops, 1))
2791 command |= FTRACE_UPDATE_CALLS;
2792
2793 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2794
2795 if (saved_ftrace_func != ftrace_trace_function) {
2796 saved_ftrace_func = ftrace_trace_function;
2797 command |= FTRACE_UPDATE_TRACE_FUNC;
2798 }
2799
2800 if (!command || !ftrace_enabled) {
2801 /*
2802 * If these are dynamic or per_cpu ops, they still
2803 * need their data freed. Since, function tracing is
2804 * not currently active, we can just free them
2805 * without synchronizing all CPUs.
2806 */
2807 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2808 goto free_ops;
2809
2810 return 0;
2811 }
2812
2813 /*
2814 * If the ops uses a trampoline, then it needs to be
2815 * tested first on update.
2816 */
2817 ops->flags |= FTRACE_OPS_FL_REMOVING;
2818 removed_ops = ops;
2819
2820 /* The trampoline logic checks the old hashes */
2821 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2822 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2823
2824 ftrace_run_update_code(command);
2825
2826 /*
2827 * If there's no more ops registered with ftrace, run a
2828 * sanity check to make sure all rec flags are cleared.
2829 */
2830 if (rcu_dereference_protected(ftrace_ops_list,
2831 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2832 struct ftrace_page *pg;
2833 struct dyn_ftrace *rec;
2834
2835 do_for_each_ftrace_rec(pg, rec) {
2836 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2837 pr_warn(" %pS flags:%lx\n",
2838 (void *)rec->ip, rec->flags);
2839 } while_for_each_ftrace_rec();
2840 }
2841
2842 ops->old_hash.filter_hash = NULL;
2843 ops->old_hash.notrace_hash = NULL;
2844
2845 removed_ops = NULL;
2846 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2847
2848 /*
2849 * Dynamic ops may be freed, we must make sure that all
2850 * callers are done before leaving this function.
2851 * The same goes for freeing the per_cpu data of the per_cpu
2852 * ops.
2853 */
2854 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2855 /*
2856 * We need to do a hard force of sched synchronization.
2857 * This is because we use preempt_disable() to do RCU, but
2858 * the function tracers can be called where RCU is not watching
2859 * (like before user_exit()). We can not rely on the RCU
2860 * infrastructure to do the synchronization, thus we must do it
2861 * ourselves.
2862 */
2863 schedule_on_each_cpu(ftrace_sync);
2864
2865 /*
2866 * When the kernel is preeptive, tasks can be preempted
2867 * while on a ftrace trampoline. Just scheduling a task on
2868 * a CPU is not good enough to flush them. Calling
2869 * synchornize_rcu_tasks() will wait for those tasks to
2870 * execute and either schedule voluntarily or enter user space.
2871 */
2872 if (IS_ENABLED(CONFIG_PREEMPT))
2873 synchronize_rcu_tasks();
2874
2875 free_ops:
2876 arch_ftrace_trampoline_free(ops);
2877 }
2878
2879 return 0;
2880}
2881
2882static void ftrace_startup_sysctl(void)
2883{
2884 int command;
2885
2886 if (unlikely(ftrace_disabled))
2887 return;
2888
2889 /* Force update next time */
2890 saved_ftrace_func = NULL;
2891 /* ftrace_start_up is true if we want ftrace running */
2892 if (ftrace_start_up) {
2893 command = FTRACE_UPDATE_CALLS;
2894 if (ftrace_graph_active)
2895 command |= FTRACE_START_FUNC_RET;
2896 ftrace_startup_enable(command);
2897 }
2898}
2899
2900static void ftrace_shutdown_sysctl(void)
2901{
2902 int command;
2903
2904 if (unlikely(ftrace_disabled))
2905 return;
2906
2907 /* ftrace_start_up is true if ftrace is running */
2908 if (ftrace_start_up) {
2909 command = FTRACE_DISABLE_CALLS;
2910 if (ftrace_graph_active)
2911 command |= FTRACE_STOP_FUNC_RET;
2912 ftrace_run_update_code(command);
2913 }
2914}
2915
2916static u64 ftrace_update_time;
2917unsigned long ftrace_update_tot_cnt;
2918
2919static inline int ops_traces_mod(struct ftrace_ops *ops)
2920{
2921 /*
2922 * Filter_hash being empty will default to trace module.
2923 * But notrace hash requires a test of individual module functions.
2924 */
2925 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2926 ftrace_hash_empty(ops->func_hash->notrace_hash);
2927}
2928
2929/*
2930 * Check if the current ops references the record.
2931 *
2932 * If the ops traces all functions, then it was already accounted for.
2933 * If the ops does not trace the current record function, skip it.
2934 * If the ops ignores the function via notrace filter, skip it.
2935 */
2936static inline bool
2937ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2938{
2939 /* If ops isn't enabled, ignore it */
2940 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2941 return 0;
2942
2943 /* If ops traces all then it includes this function */
2944 if (ops_traces_mod(ops))
2945 return 1;
2946
2947 /* The function must be in the filter */
2948 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2949 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2950 return 0;
2951
2952 /* If in notrace hash, we ignore it too */
2953 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2954 return 0;
2955
2956 return 1;
2957}
2958
2959static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2960{
2961 struct ftrace_page *pg;
2962 struct dyn_ftrace *p;
2963 u64 start, stop;
2964 unsigned long update_cnt = 0;
2965 unsigned long rec_flags = 0;
2966 int i;
2967
2968 start = ftrace_now(raw_smp_processor_id());
2969
2970 /*
2971 * When a module is loaded, this function is called to convert
2972 * the calls to mcount in its text to nops, and also to create
2973 * an entry in the ftrace data. Now, if ftrace is activated
2974 * after this call, but before the module sets its text to
2975 * read-only, the modification of enabling ftrace can fail if
2976 * the read-only is done while ftrace is converting the calls.
2977 * To prevent this, the module's records are set as disabled
2978 * and will be enabled after the call to set the module's text
2979 * to read-only.
2980 */
2981 if (mod)
2982 rec_flags |= FTRACE_FL_DISABLED;
2983
2984 for (pg = new_pgs; pg; pg = pg->next) {
2985
2986 for (i = 0; i < pg->index; i++) {
2987
2988 /* If something went wrong, bail without enabling anything */
2989 if (unlikely(ftrace_disabled))
2990 return -1;
2991
2992 p = &pg->records[i];
2993 p->flags = rec_flags;
2994
2995 /*
2996 * Do the initial record conversion from mcount jump
2997 * to the NOP instructions.
2998 */
2999 if (!ftrace_code_disable(mod, p))
3000 break;
3001
3002 update_cnt++;
3003 }
3004 }
3005
3006 stop = ftrace_now(raw_smp_processor_id());
3007 ftrace_update_time = stop - start;
3008 ftrace_update_tot_cnt += update_cnt;
3009
3010 return 0;
3011}
3012
3013static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3014{
3015 int order;
3016 int cnt;
3017
3018 if (WARN_ON(!count))
3019 return -EINVAL;
3020
3021 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3022
3023 /*
3024 * We want to fill as much as possible. No more than a page
3025 * may be empty.
3026 */
3027 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3028 order--;
3029
3030 again:
3031 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3032
3033 if (!pg->records) {
3034 /* if we can't allocate this size, try something smaller */
3035 if (!order)
3036 return -ENOMEM;
3037 order >>= 1;
3038 goto again;
3039 }
3040
3041 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3042 pg->size = cnt;
3043
3044 if (cnt > count)
3045 cnt = count;
3046
3047 return cnt;
3048}
3049
3050static struct ftrace_page *
3051ftrace_allocate_pages(unsigned long num_to_init)
3052{
3053 struct ftrace_page *start_pg;
3054 struct ftrace_page *pg;
3055 int order;
3056 int cnt;
3057
3058 if (!num_to_init)
3059 return 0;
3060
3061 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3062 if (!pg)
3063 return NULL;
3064
3065 /*
3066 * Try to allocate as much as possible in one continues
3067 * location that fills in all of the space. We want to
3068 * waste as little space as possible.
3069 */
3070 for (;;) {
3071 cnt = ftrace_allocate_records(pg, num_to_init);
3072 if (cnt < 0)
3073 goto free_pages;
3074
3075 num_to_init -= cnt;
3076 if (!num_to_init)
3077 break;
3078
3079 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3080 if (!pg->next)
3081 goto free_pages;
3082
3083 pg = pg->next;
3084 }
3085
3086 return start_pg;
3087
3088 free_pages:
3089 pg = start_pg;
3090 while (pg) {
3091 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3092 free_pages((unsigned long)pg->records, order);
3093 start_pg = pg->next;
3094 kfree(pg);
3095 pg = start_pg;
3096 }
3097 pr_info("ftrace: FAILED to allocate memory for functions\n");
3098 return NULL;
3099}
3100
3101#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3102
3103struct ftrace_iterator {
3104 loff_t pos;
3105 loff_t func_pos;
3106 loff_t mod_pos;
3107 struct ftrace_page *pg;
3108 struct dyn_ftrace *func;
3109 struct ftrace_func_probe *probe;
3110 struct ftrace_func_entry *probe_entry;
3111 struct trace_parser parser;
3112 struct ftrace_hash *hash;
3113 struct ftrace_ops *ops;
3114 struct trace_array *tr;
3115 struct list_head *mod_list;
3116 int pidx;
3117 int idx;
3118 unsigned flags;
3119};
3120
3121static void *
3122t_probe_next(struct seq_file *m, loff_t *pos)
3123{
3124 struct ftrace_iterator *iter = m->private;
3125 struct trace_array *tr = iter->ops->private;
3126 struct list_head *func_probes;
3127 struct ftrace_hash *hash;
3128 struct list_head *next;
3129 struct hlist_node *hnd = NULL;
3130 struct hlist_head *hhd;
3131 int size;
3132
3133 (*pos)++;
3134 iter->pos = *pos;
3135
3136 if (!tr)
3137 return NULL;
3138
3139 func_probes = &tr->func_probes;
3140 if (list_empty(func_probes))
3141 return NULL;
3142
3143 if (!iter->probe) {
3144 next = func_probes->next;
3145 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3146 }
3147
3148 if (iter->probe_entry)
3149 hnd = &iter->probe_entry->hlist;
3150
3151 hash = iter->probe->ops.func_hash->filter_hash;
3152 size = 1 << hash->size_bits;
3153
3154 retry:
3155 if (iter->pidx >= size) {
3156 if (iter->probe->list.next == func_probes)
3157 return NULL;
3158 next = iter->probe->list.next;
3159 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3160 hash = iter->probe->ops.func_hash->filter_hash;
3161 size = 1 << hash->size_bits;
3162 iter->pidx = 0;
3163 }
3164
3165 hhd = &hash->buckets[iter->pidx];
3166
3167 if (hlist_empty(hhd)) {
3168 iter->pidx++;
3169 hnd = NULL;
3170 goto retry;
3171 }
3172
3173 if (!hnd)
3174 hnd = hhd->first;
3175 else {
3176 hnd = hnd->next;
3177 if (!hnd) {
3178 iter->pidx++;
3179 goto retry;
3180 }
3181 }
3182
3183 if (WARN_ON_ONCE(!hnd))
3184 return NULL;
3185
3186 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3187
3188 return iter;
3189}
3190
3191static void *t_probe_start(struct seq_file *m, loff_t *pos)
3192{
3193 struct ftrace_iterator *iter = m->private;
3194 void *p = NULL;
3195 loff_t l;
3196
3197 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3198 return NULL;
3199
3200 if (iter->mod_pos > *pos)
3201 return NULL;
3202
3203 iter->probe = NULL;
3204 iter->probe_entry = NULL;
3205 iter->pidx = 0;
3206 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3207 p = t_probe_next(m, &l);
3208 if (!p)
3209 break;
3210 }
3211 if (!p)
3212 return NULL;
3213
3214 /* Only set this if we have an item */
3215 iter->flags |= FTRACE_ITER_PROBE;
3216
3217 return iter;
3218}
3219
3220static int
3221t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3222{
3223 struct ftrace_func_entry *probe_entry;
3224 struct ftrace_probe_ops *probe_ops;
3225 struct ftrace_func_probe *probe;
3226
3227 probe = iter->probe;
3228 probe_entry = iter->probe_entry;
3229
3230 if (WARN_ON_ONCE(!probe || !probe_entry))
3231 return -EIO;
3232
3233 probe_ops = probe->probe_ops;
3234
3235 if (probe_ops->print)
3236 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3237
3238 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3239 (void *)probe_ops->func);
3240
3241 return 0;
3242}
3243
3244static void *
3245t_mod_next(struct seq_file *m, loff_t *pos)
3246{
3247 struct ftrace_iterator *iter = m->private;
3248 struct trace_array *tr = iter->tr;
3249
3250 (*pos)++;
3251 iter->pos = *pos;
3252
3253 iter->mod_list = iter->mod_list->next;
3254
3255 if (iter->mod_list == &tr->mod_trace ||
3256 iter->mod_list == &tr->mod_notrace) {
3257 iter->flags &= ~FTRACE_ITER_MOD;
3258 return NULL;
3259 }
3260
3261 iter->mod_pos = *pos;
3262
3263 return iter;
3264}
3265
3266static void *t_mod_start(struct seq_file *m, loff_t *pos)
3267{
3268 struct ftrace_iterator *iter = m->private;
3269 void *p = NULL;
3270 loff_t l;
3271
3272 if (iter->func_pos > *pos)
3273 return NULL;
3274
3275 iter->mod_pos = iter->func_pos;
3276
3277 /* probes are only available if tr is set */
3278 if (!iter->tr)
3279 return NULL;
3280
3281 for (l = 0; l <= (*pos - iter->func_pos); ) {
3282 p = t_mod_next(m, &l);
3283 if (!p)
3284 break;
3285 }
3286 if (!p) {
3287 iter->flags &= ~FTRACE_ITER_MOD;
3288 return t_probe_start(m, pos);
3289 }
3290
3291 /* Only set this if we have an item */
3292 iter->flags |= FTRACE_ITER_MOD;
3293
3294 return iter;
3295}
3296
3297static int
3298t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3299{
3300 struct ftrace_mod_load *ftrace_mod;
3301 struct trace_array *tr = iter->tr;
3302
3303 if (WARN_ON_ONCE(!iter->mod_list) ||
3304 iter->mod_list == &tr->mod_trace ||
3305 iter->mod_list == &tr->mod_notrace)
3306 return -EIO;
3307
3308 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3309
3310 if (ftrace_mod->func)
3311 seq_printf(m, "%s", ftrace_mod->func);
3312 else
3313 seq_putc(m, '*');
3314
3315 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3316
3317 return 0;
3318}
3319
3320static void *
3321t_func_next(struct seq_file *m, loff_t *pos)
3322{
3323 struct ftrace_iterator *iter = m->private;
3324 struct dyn_ftrace *rec = NULL;
3325
3326 (*pos)++;
3327
3328 retry:
3329 if (iter->idx >= iter->pg->index) {
3330 if (iter->pg->next) {
3331 iter->pg = iter->pg->next;
3332 iter->idx = 0;
3333 goto retry;
3334 }
3335 } else {
3336 rec = &iter->pg->records[iter->idx++];
3337 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3338 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3339
3340 ((iter->flags & FTRACE_ITER_ENABLED) &&
3341 !(rec->flags & FTRACE_FL_ENABLED))) {
3342
3343 rec = NULL;
3344 goto retry;
3345 }
3346 }
3347
3348 if (!rec)
3349 return NULL;
3350
3351 iter->pos = iter->func_pos = *pos;
3352 iter->func = rec;
3353
3354 return iter;
3355}
3356
3357static void *
3358t_next(struct seq_file *m, void *v, loff_t *pos)
3359{
3360 struct ftrace_iterator *iter = m->private;
3361 loff_t l = *pos; /* t_probe_start() must use original pos */
3362 void *ret;
3363
3364 if (unlikely(ftrace_disabled))
3365 return NULL;
3366
3367 if (iter->flags & FTRACE_ITER_PROBE)
3368 return t_probe_next(m, pos);
3369
3370 if (iter->flags & FTRACE_ITER_MOD)
3371 return t_mod_next(m, pos);
3372
3373 if (iter->flags & FTRACE_ITER_PRINTALL) {
3374 /* next must increment pos, and t_probe_start does not */
3375 (*pos)++;
3376 return t_mod_start(m, &l);
3377 }
3378
3379 ret = t_func_next(m, pos);
3380
3381 if (!ret)
3382 return t_mod_start(m, &l);
3383
3384 return ret;
3385}
3386
3387static void reset_iter_read(struct ftrace_iterator *iter)
3388{
3389 iter->pos = 0;
3390 iter->func_pos = 0;
3391 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3392}
3393
3394static void *t_start(struct seq_file *m, loff_t *pos)
3395{
3396 struct ftrace_iterator *iter = m->private;
3397 void *p = NULL;
3398 loff_t l;
3399
3400 mutex_lock(&ftrace_lock);
3401
3402 if (unlikely(ftrace_disabled))
3403 return NULL;
3404
3405 /*
3406 * If an lseek was done, then reset and start from beginning.
3407 */
3408 if (*pos < iter->pos)
3409 reset_iter_read(iter);
3410
3411 /*
3412 * For set_ftrace_filter reading, if we have the filter
3413 * off, we can short cut and just print out that all
3414 * functions are enabled.
3415 */
3416 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3417 ftrace_hash_empty(iter->hash)) {
3418 iter->func_pos = 1; /* Account for the message */
3419 if (*pos > 0)
3420 return t_mod_start(m, pos);
3421 iter->flags |= FTRACE_ITER_PRINTALL;
3422 /* reset in case of seek/pread */
3423 iter->flags &= ~FTRACE_ITER_PROBE;
3424 return iter;
3425 }
3426
3427 if (iter->flags & FTRACE_ITER_MOD)
3428 return t_mod_start(m, pos);
3429
3430 /*
3431 * Unfortunately, we need to restart at ftrace_pages_start
3432 * every time we let go of the ftrace_mutex. This is because
3433 * those pointers can change without the lock.
3434 */
3435 iter->pg = ftrace_pages_start;
3436 iter->idx = 0;
3437 for (l = 0; l <= *pos; ) {
3438 p = t_func_next(m, &l);
3439 if (!p)
3440 break;
3441 }
3442
3443 if (!p)
3444 return t_mod_start(m, pos);
3445
3446 return iter;
3447}
3448
3449static void t_stop(struct seq_file *m, void *p)
3450{
3451 mutex_unlock(&ftrace_lock);
3452}
3453
3454void * __weak
3455arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3456{
3457 return NULL;
3458}
3459
3460static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3461 struct dyn_ftrace *rec)
3462{
3463 void *ptr;
3464
3465 ptr = arch_ftrace_trampoline_func(ops, rec);
3466 if (ptr)
3467 seq_printf(m, " ->%pS", ptr);
3468}
3469
3470static int t_show(struct seq_file *m, void *v)
3471{
3472 struct ftrace_iterator *iter = m->private;
3473 struct dyn_ftrace *rec;
3474
3475 if (iter->flags & FTRACE_ITER_PROBE)
3476 return t_probe_show(m, iter);
3477
3478 if (iter->flags & FTRACE_ITER_MOD)
3479 return t_mod_show(m, iter);
3480
3481 if (iter->flags & FTRACE_ITER_PRINTALL) {
3482 if (iter->flags & FTRACE_ITER_NOTRACE)
3483 seq_puts(m, "#### no functions disabled ####\n");
3484 else
3485 seq_puts(m, "#### all functions enabled ####\n");
3486 return 0;
3487 }
3488
3489 rec = iter->func;
3490
3491 if (!rec)
3492 return 0;
3493
3494 seq_printf(m, "%ps", (void *)rec->ip);
3495 if (iter->flags & FTRACE_ITER_ENABLED) {
3496 struct ftrace_ops *ops;
3497
3498 seq_printf(m, " (%ld)%s%s",
3499 ftrace_rec_count(rec),
3500 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3501 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3502 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3503 ops = ftrace_find_tramp_ops_any(rec);
3504 if (ops) {
3505 do {
3506 seq_printf(m, "\ttramp: %pS (%pS)",
3507 (void *)ops->trampoline,
3508 (void *)ops->func);
3509 add_trampoline_func(m, ops, rec);
3510 ops = ftrace_find_tramp_ops_next(rec, ops);
3511 } while (ops);
3512 } else
3513 seq_puts(m, "\ttramp: ERROR!");
3514 } else {
3515 add_trampoline_func(m, NULL, rec);
3516 }
3517 }
3518
3519 seq_putc(m, '\n');
3520
3521 return 0;
3522}
3523
3524static const struct seq_operations show_ftrace_seq_ops = {
3525 .start = t_start,
3526 .next = t_next,
3527 .stop = t_stop,
3528 .show = t_show,
3529};
3530
3531static int
3532ftrace_avail_open(struct inode *inode, struct file *file)
3533{
3534 struct ftrace_iterator *iter;
3535
3536 if (unlikely(ftrace_disabled))
3537 return -ENODEV;
3538
3539 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3540 if (!iter)
3541 return -ENOMEM;
3542
3543 iter->pg = ftrace_pages_start;
3544 iter->ops = &global_ops;
3545
3546 return 0;
3547}
3548
3549static int
3550ftrace_enabled_open(struct inode *inode, struct file *file)
3551{
3552 struct ftrace_iterator *iter;
3553
3554 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3555 if (!iter)
3556 return -ENOMEM;
3557
3558 iter->pg = ftrace_pages_start;
3559 iter->flags = FTRACE_ITER_ENABLED;
3560 iter->ops = &global_ops;
3561
3562 return 0;
3563}
3564
3565/**
3566 * ftrace_regex_open - initialize function tracer filter files
3567 * @ops: The ftrace_ops that hold the hash filters
3568 * @flag: The type of filter to process
3569 * @inode: The inode, usually passed in to your open routine
3570 * @file: The file, usually passed in to your open routine
3571 *
3572 * ftrace_regex_open() initializes the filter files for the
3573 * @ops. Depending on @flag it may process the filter hash or
3574 * the notrace hash of @ops. With this called from the open
3575 * routine, you can use ftrace_filter_write() for the write
3576 * routine if @flag has FTRACE_ITER_FILTER set, or
3577 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3578 * tracing_lseek() should be used as the lseek routine, and
3579 * release must call ftrace_regex_release().
3580 */
3581int
3582ftrace_regex_open(struct ftrace_ops *ops, int flag,
3583 struct inode *inode, struct file *file)
3584{
3585 struct ftrace_iterator *iter;
3586 struct ftrace_hash *hash;
3587 struct list_head *mod_head;
3588 struct trace_array *tr = ops->private;
3589 int ret = 0;
3590
3591 ftrace_ops_init(ops);
3592
3593 if (unlikely(ftrace_disabled))
3594 return -ENODEV;
3595
3596 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3597 if (!iter)
3598 return -ENOMEM;
3599
3600 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3601 kfree(iter);
3602 return -ENOMEM;
3603 }
3604
3605 iter->ops = ops;
3606 iter->flags = flag;
3607 iter->tr = tr;
3608
3609 mutex_lock(&ops->func_hash->regex_lock);
3610
3611 if (flag & FTRACE_ITER_NOTRACE) {
3612 hash = ops->func_hash->notrace_hash;
3613 mod_head = tr ? &tr->mod_notrace : NULL;
3614 } else {
3615 hash = ops->func_hash->filter_hash;
3616 mod_head = tr ? &tr->mod_trace : NULL;
3617 }
3618
3619 iter->mod_list = mod_head;
3620
3621 if (file->f_mode & FMODE_WRITE) {
3622 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3623
3624 if (file->f_flags & O_TRUNC) {
3625 iter->hash = alloc_ftrace_hash(size_bits);
3626 clear_ftrace_mod_list(mod_head);
3627 } else {
3628 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3629 }
3630
3631 if (!iter->hash) {
3632 trace_parser_put(&iter->parser);
3633 kfree(iter);
3634 ret = -ENOMEM;
3635 goto out_unlock;
3636 }
3637 } else
3638 iter->hash = hash;
3639
3640 if (file->f_mode & FMODE_READ) {
3641 iter->pg = ftrace_pages_start;
3642
3643 ret = seq_open(file, &show_ftrace_seq_ops);
3644 if (!ret) {
3645 struct seq_file *m = file->private_data;
3646 m->private = iter;
3647 } else {
3648 /* Failed */
3649 free_ftrace_hash(iter->hash);
3650 trace_parser_put(&iter->parser);
3651 kfree(iter);
3652 }
3653 } else
3654 file->private_data = iter;
3655
3656 out_unlock:
3657 mutex_unlock(&ops->func_hash->regex_lock);
3658
3659 return ret;
3660}
3661
3662static int
3663ftrace_filter_open(struct inode *inode, struct file *file)
3664{
3665 struct ftrace_ops *ops = inode->i_private;
3666
3667 return ftrace_regex_open(ops,
3668 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3669 inode, file);
3670}
3671
3672static int
3673ftrace_notrace_open(struct inode *inode, struct file *file)
3674{
3675 struct ftrace_ops *ops = inode->i_private;
3676
3677 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3678 inode, file);
3679}
3680
3681/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3682struct ftrace_glob {
3683 char *search;
3684 unsigned len;
3685 int type;
3686};
3687
3688/*
3689 * If symbols in an architecture don't correspond exactly to the user-visible
3690 * name of what they represent, it is possible to define this function to
3691 * perform the necessary adjustments.
3692*/
3693char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3694{
3695 return str;
3696}
3697
3698static int ftrace_match(char *str, struct ftrace_glob *g)
3699{
3700 int matched = 0;
3701 int slen;
3702
3703 str = arch_ftrace_match_adjust(str, g->search);
3704
3705 switch (g->type) {
3706 case MATCH_FULL:
3707 if (strcmp(str, g->search) == 0)
3708 matched = 1;
3709 break;
3710 case MATCH_FRONT_ONLY:
3711 if (strncmp(str, g->search, g->len) == 0)
3712 matched = 1;
3713 break;
3714 case MATCH_MIDDLE_ONLY:
3715 if (strstr(str, g->search))
3716 matched = 1;
3717 break;
3718 case MATCH_END_ONLY:
3719 slen = strlen(str);
3720 if (slen >= g->len &&
3721 memcmp(str + slen - g->len, g->search, g->len) == 0)
3722 matched = 1;
3723 break;
3724 case MATCH_GLOB:
3725 if (glob_match(g->search, str))
3726 matched = 1;
3727 break;
3728 }
3729
3730 return matched;
3731}
3732
3733static int
3734enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3735{
3736 struct ftrace_func_entry *entry;
3737 int ret = 0;
3738
3739 entry = ftrace_lookup_ip(hash, rec->ip);
3740 if (clear_filter) {
3741 /* Do nothing if it doesn't exist */
3742 if (!entry)
3743 return 0;
3744
3745 free_hash_entry(hash, entry);
3746 } else {
3747 /* Do nothing if it exists */
3748 if (entry)
3749 return 0;
3750
3751 ret = add_hash_entry(hash, rec->ip);
3752 }
3753 return ret;
3754}
3755
3756static int
3757ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3758 struct ftrace_glob *mod_g, int exclude_mod)
3759{
3760 char str[KSYM_SYMBOL_LEN];
3761 char *modname;
3762
3763 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3764
3765 if (mod_g) {
3766 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3767
3768 /* blank module name to match all modules */
3769 if (!mod_g->len) {
3770 /* blank module globbing: modname xor exclude_mod */
3771 if (!exclude_mod != !modname)
3772 goto func_match;
3773 return 0;
3774 }
3775
3776 /*
3777 * exclude_mod is set to trace everything but the given
3778 * module. If it is set and the module matches, then
3779 * return 0. If it is not set, and the module doesn't match
3780 * also return 0. Otherwise, check the function to see if
3781 * that matches.
3782 */
3783 if (!mod_matches == !exclude_mod)
3784 return 0;
3785func_match:
3786 /* blank search means to match all funcs in the mod */
3787 if (!func_g->len)
3788 return 1;
3789 }
3790
3791 return ftrace_match(str, func_g);
3792}
3793
3794static int
3795match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3796{
3797 struct ftrace_page *pg;
3798 struct dyn_ftrace *rec;
3799 struct ftrace_glob func_g = { .type = MATCH_FULL };
3800 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3801 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3802 int exclude_mod = 0;
3803 int found = 0;
3804 int ret;
3805 int clear_filter = 0;
3806
3807 if (func) {
3808 func_g.type = filter_parse_regex(func, len, &func_g.search,
3809 &clear_filter);
3810 func_g.len = strlen(func_g.search);
3811 }
3812
3813 if (mod) {
3814 mod_g.type = filter_parse_regex(mod, strlen(mod),
3815 &mod_g.search, &exclude_mod);
3816 mod_g.len = strlen(mod_g.search);
3817 }
3818
3819 mutex_lock(&ftrace_lock);
3820
3821 if (unlikely(ftrace_disabled))
3822 goto out_unlock;
3823
3824 do_for_each_ftrace_rec(pg, rec) {
3825
3826 if (rec->flags & FTRACE_FL_DISABLED)
3827 continue;
3828
3829 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3830 ret = enter_record(hash, rec, clear_filter);
3831 if (ret < 0) {
3832 found = ret;
3833 goto out_unlock;
3834 }
3835 found = 1;
3836 }
3837 } while_for_each_ftrace_rec();
3838 out_unlock:
3839 mutex_unlock(&ftrace_lock);
3840
3841 return found;
3842}
3843
3844static int
3845ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3846{
3847 return match_records(hash, buff, len, NULL);
3848}
3849
3850static void ftrace_ops_update_code(struct ftrace_ops *ops,
3851 struct ftrace_ops_hash *old_hash)
3852{
3853 struct ftrace_ops *op;
3854
3855 if (!ftrace_enabled)
3856 return;
3857
3858 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3859 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3860 return;
3861 }
3862
3863 /*
3864 * If this is the shared global_ops filter, then we need to
3865 * check if there is another ops that shares it, is enabled.
3866 * If so, we still need to run the modify code.
3867 */
3868 if (ops->func_hash != &global_ops.local_hash)
3869 return;
3870
3871 do_for_each_ftrace_op(op, ftrace_ops_list) {
3872 if (op->func_hash == &global_ops.local_hash &&
3873 op->flags & FTRACE_OPS_FL_ENABLED) {
3874 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3875 /* Only need to do this once */
3876 return;
3877 }
3878 } while_for_each_ftrace_op(op);
3879}
3880
3881static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3882 struct ftrace_hash **orig_hash,
3883 struct ftrace_hash *hash,
3884 int enable)
3885{
3886 struct ftrace_ops_hash old_hash_ops;
3887 struct ftrace_hash *old_hash;
3888 int ret;
3889
3890 old_hash = *orig_hash;
3891 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3892 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3893 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3894 if (!ret) {
3895 ftrace_ops_update_code(ops, &old_hash_ops);
3896 free_ftrace_hash_rcu(old_hash);
3897 }
3898 return ret;
3899}
3900
3901static bool module_exists(const char *module)
3902{
3903 /* All modules have the symbol __this_module */
3904 const char this_mod[] = "__this_module";
3905 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
3906 unsigned long val;
3907 int n;
3908
3909 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
3910
3911 if (n > sizeof(modname) - 1)
3912 return false;
3913
3914 val = module_kallsyms_lookup_name(modname);
3915 return val != 0;
3916}
3917
3918static int cache_mod(struct trace_array *tr,
3919 const char *func, char *module, int enable)
3920{
3921 struct ftrace_mod_load *ftrace_mod, *n;
3922 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3923 int ret;
3924
3925 mutex_lock(&ftrace_lock);
3926
3927 /* We do not cache inverse filters */
3928 if (func[0] == '!') {
3929 func++;
3930 ret = -EINVAL;
3931
3932 /* Look to remove this hash */
3933 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3934 if (strcmp(ftrace_mod->module, module) != 0)
3935 continue;
3936
3937 /* no func matches all */
3938 if (strcmp(func, "*") == 0 ||
3939 (ftrace_mod->func &&
3940 strcmp(ftrace_mod->func, func) == 0)) {
3941 ret = 0;
3942 free_ftrace_mod(ftrace_mod);
3943 continue;
3944 }
3945 }
3946 goto out;
3947 }
3948
3949 ret = -EINVAL;
3950 /* We only care about modules that have not been loaded yet */
3951 if (module_exists(module))
3952 goto out;
3953
3954 /* Save this string off, and execute it when the module is loaded */
3955 ret = ftrace_add_mod(tr, func, module, enable);
3956 out:
3957 mutex_unlock(&ftrace_lock);
3958
3959 return ret;
3960}
3961
3962static int
3963ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3964 int reset, int enable);
3965
3966#ifdef CONFIG_MODULES
3967static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3968 char *mod, bool enable)
3969{
3970 struct ftrace_mod_load *ftrace_mod, *n;
3971 struct ftrace_hash **orig_hash, *new_hash;
3972 LIST_HEAD(process_mods);
3973 char *func;
3974 int ret;
3975
3976 mutex_lock(&ops->func_hash->regex_lock);
3977
3978 if (enable)
3979 orig_hash = &ops->func_hash->filter_hash;
3980 else
3981 orig_hash = &ops->func_hash->notrace_hash;
3982
3983 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
3984 *orig_hash);
3985 if (!new_hash)
3986 goto out; /* warn? */
3987
3988 mutex_lock(&ftrace_lock);
3989
3990 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3991
3992 if (strcmp(ftrace_mod->module, mod) != 0)
3993 continue;
3994
3995 if (ftrace_mod->func)
3996 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
3997 else
3998 func = kstrdup("*", GFP_KERNEL);
3999
4000 if (!func) /* warn? */
4001 continue;
4002
4003 list_del(&ftrace_mod->list);
4004 list_add(&ftrace_mod->list, &process_mods);
4005
4006 /* Use the newly allocated func, as it may be "*" */
4007 kfree(ftrace_mod->func);
4008 ftrace_mod->func = func;
4009 }
4010
4011 mutex_unlock(&ftrace_lock);
4012
4013 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4014
4015 func = ftrace_mod->func;
4016
4017 /* Grabs ftrace_lock, which is why we have this extra step */
4018 match_records(new_hash, func, strlen(func), mod);
4019 free_ftrace_mod(ftrace_mod);
4020 }
4021
4022 if (enable && list_empty(head))
4023 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4024
4025 mutex_lock(&ftrace_lock);
4026
4027 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4028 new_hash, enable);
4029 mutex_unlock(&ftrace_lock);
4030
4031 out:
4032 mutex_unlock(&ops->func_hash->regex_lock);
4033
4034 free_ftrace_hash(new_hash);
4035}
4036
4037static void process_cached_mods(const char *mod_name)
4038{
4039 struct trace_array *tr;
4040 char *mod;
4041
4042 mod = kstrdup(mod_name, GFP_KERNEL);
4043 if (!mod)
4044 return;
4045
4046 mutex_lock(&trace_types_lock);
4047 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4048 if (!list_empty(&tr->mod_trace))
4049 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4050 if (!list_empty(&tr->mod_notrace))
4051 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4052 }
4053 mutex_unlock(&trace_types_lock);
4054
4055 kfree(mod);
4056}
4057#endif
4058
4059/*
4060 * We register the module command as a template to show others how
4061 * to register the a command as well.
4062 */
4063
4064static int
4065ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4066 char *func_orig, char *cmd, char *module, int enable)
4067{
4068 char *func;
4069 int ret;
4070
4071 /* match_records() modifies func, and we need the original */
4072 func = kstrdup(func_orig, GFP_KERNEL);
4073 if (!func)
4074 return -ENOMEM;
4075
4076 /*
4077 * cmd == 'mod' because we only registered this func
4078 * for the 'mod' ftrace_func_command.
4079 * But if you register one func with multiple commands,
4080 * you can tell which command was used by the cmd
4081 * parameter.
4082 */
4083 ret = match_records(hash, func, strlen(func), module);
4084 kfree(func);
4085
4086 if (!ret)
4087 return cache_mod(tr, func_orig, module, enable);
4088 if (ret < 0)
4089 return ret;
4090 return 0;
4091}
4092
4093static struct ftrace_func_command ftrace_mod_cmd = {
4094 .name = "mod",
4095 .func = ftrace_mod_callback,
4096};
4097
4098static int __init ftrace_mod_cmd_init(void)
4099{
4100 return register_ftrace_command(&ftrace_mod_cmd);
4101}
4102core_initcall(ftrace_mod_cmd_init);
4103
4104static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4105 struct ftrace_ops *op, struct pt_regs *pt_regs)
4106{
4107 struct ftrace_probe_ops *probe_ops;
4108 struct ftrace_func_probe *probe;
4109
4110 probe = container_of(op, struct ftrace_func_probe, ops);
4111 probe_ops = probe->probe_ops;
4112
4113 /*
4114 * Disable preemption for these calls to prevent a RCU grace
4115 * period. This syncs the hash iteration and freeing of items
4116 * on the hash. rcu_read_lock is too dangerous here.
4117 */
4118 preempt_disable_notrace();
4119 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4120 preempt_enable_notrace();
4121}
4122
4123struct ftrace_func_map {
4124 struct ftrace_func_entry entry;
4125 void *data;
4126};
4127
4128struct ftrace_func_mapper {
4129 struct ftrace_hash hash;
4130};
4131
4132/**
4133 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4134 *
4135 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4136 */
4137struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4138{
4139 struct ftrace_hash *hash;
4140
4141 /*
4142 * The mapper is simply a ftrace_hash, but since the entries
4143 * in the hash are not ftrace_func_entry type, we define it
4144 * as a separate structure.
4145 */
4146 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4147 return (struct ftrace_func_mapper *)hash;
4148}
4149
4150/**
4151 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4152 * @mapper: The mapper that has the ip maps
4153 * @ip: the instruction pointer to find the data for
4154 *
4155 * Returns the data mapped to @ip if found otherwise NULL. The return
4156 * is actually the address of the mapper data pointer. The address is
4157 * returned for use cases where the data is no bigger than a long, and
4158 * the user can use the data pointer as its data instead of having to
4159 * allocate more memory for the reference.
4160 */
4161void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4162 unsigned long ip)
4163{
4164 struct ftrace_func_entry *entry;
4165 struct ftrace_func_map *map;
4166
4167 entry = ftrace_lookup_ip(&mapper->hash, ip);
4168 if (!entry)
4169 return NULL;
4170
4171 map = (struct ftrace_func_map *)entry;
4172 return &map->data;
4173}
4174
4175/**
4176 * ftrace_func_mapper_add_ip - Map some data to an ip
4177 * @mapper: The mapper that has the ip maps
4178 * @ip: The instruction pointer address to map @data to
4179 * @data: The data to map to @ip
4180 *
4181 * Returns 0 on succes otherwise an error.
4182 */
4183int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4184 unsigned long ip, void *data)
4185{
4186 struct ftrace_func_entry *entry;
4187 struct ftrace_func_map *map;
4188
4189 entry = ftrace_lookup_ip(&mapper->hash, ip);
4190 if (entry)
4191 return -EBUSY;
4192
4193 map = kmalloc(sizeof(*map), GFP_KERNEL);
4194 if (!map)
4195 return -ENOMEM;
4196
4197 map->entry.ip = ip;
4198 map->data = data;
4199
4200 __add_hash_entry(&mapper->hash, &map->entry);
4201
4202 return 0;
4203}
4204
4205/**
4206 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4207 * @mapper: The mapper that has the ip maps
4208 * @ip: The instruction pointer address to remove the data from
4209 *
4210 * Returns the data if it is found, otherwise NULL.
4211 * Note, if the data pointer is used as the data itself, (see
4212 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4213 * if the data pointer was set to zero.
4214 */
4215void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4216 unsigned long ip)
4217{
4218 struct ftrace_func_entry *entry;
4219 struct ftrace_func_map *map;
4220 void *data;
4221
4222 entry = ftrace_lookup_ip(&mapper->hash, ip);
4223 if (!entry)
4224 return NULL;
4225
4226 map = (struct ftrace_func_map *)entry;
4227 data = map->data;
4228
4229 remove_hash_entry(&mapper->hash, entry);
4230 kfree(entry);
4231
4232 return data;
4233}
4234
4235/**
4236 * free_ftrace_func_mapper - free a mapping of ips and data
4237 * @mapper: The mapper that has the ip maps
4238 * @free_func: A function to be called on each data item.
4239 *
4240 * This is used to free the function mapper. The @free_func is optional
4241 * and can be used if the data needs to be freed as well.
4242 */
4243void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4244 ftrace_mapper_func free_func)
4245{
4246 struct ftrace_func_entry *entry;
4247 struct ftrace_func_map *map;
4248 struct hlist_head *hhd;
4249 int size = 1 << mapper->hash.size_bits;
4250 int i;
4251
4252 if (free_func && mapper->hash.count) {
4253 for (i = 0; i < size; i++) {
4254 hhd = &mapper->hash.buckets[i];
4255 hlist_for_each_entry(entry, hhd, hlist) {
4256 map = (struct ftrace_func_map *)entry;
4257 free_func(map);
4258 }
4259 }
4260 }
4261 free_ftrace_hash(&mapper->hash);
4262}
4263
4264static void release_probe(struct ftrace_func_probe *probe)
4265{
4266 struct ftrace_probe_ops *probe_ops;
4267
4268 mutex_lock(&ftrace_lock);
4269
4270 WARN_ON(probe->ref <= 0);
4271
4272 /* Subtract the ref that was used to protect this instance */
4273 probe->ref--;
4274
4275 if (!probe->ref) {
4276 probe_ops = probe->probe_ops;
4277 /*
4278 * Sending zero as ip tells probe_ops to free
4279 * the probe->data itself
4280 */
4281 if (probe_ops->free)
4282 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4283 list_del(&probe->list);
4284 kfree(probe);
4285 }
4286 mutex_unlock(&ftrace_lock);
4287}
4288
4289static void acquire_probe_locked(struct ftrace_func_probe *probe)
4290{
4291 /*
4292 * Add one ref to keep it from being freed when releasing the
4293 * ftrace_lock mutex.
4294 */
4295 probe->ref++;
4296}
4297
4298int
4299register_ftrace_function_probe(char *glob, struct trace_array *tr,
4300 struct ftrace_probe_ops *probe_ops,
4301 void *data)
4302{
4303 struct ftrace_func_entry *entry;
4304 struct ftrace_func_probe *probe;
4305 struct ftrace_hash **orig_hash;
4306 struct ftrace_hash *old_hash;
4307 struct ftrace_hash *hash;
4308 int count = 0;
4309 int size;
4310 int ret;
4311 int i;
4312
4313 if (WARN_ON(!tr))
4314 return -EINVAL;
4315
4316 /* We do not support '!' for function probes */
4317 if (WARN_ON(glob[0] == '!'))
4318 return -EINVAL;
4319
4320
4321 mutex_lock(&ftrace_lock);
4322 /* Check if the probe_ops is already registered */
4323 list_for_each_entry(probe, &tr->func_probes, list) {
4324 if (probe->probe_ops == probe_ops)
4325 break;
4326 }
4327 if (&probe->list == &tr->func_probes) {
4328 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4329 if (!probe) {
4330 mutex_unlock(&ftrace_lock);
4331 return -ENOMEM;
4332 }
4333 probe->probe_ops = probe_ops;
4334 probe->ops.func = function_trace_probe_call;
4335 probe->tr = tr;
4336 ftrace_ops_init(&probe->ops);
4337 list_add(&probe->list, &tr->func_probes);
4338 }
4339
4340 acquire_probe_locked(probe);
4341
4342 mutex_unlock(&ftrace_lock);
4343
4344 mutex_lock(&probe->ops.func_hash->regex_lock);
4345
4346 orig_hash = &probe->ops.func_hash->filter_hash;
4347 old_hash = *orig_hash;
4348 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4349
4350 ret = ftrace_match_records(hash, glob, strlen(glob));
4351
4352 /* Nothing found? */
4353 if (!ret)
4354 ret = -EINVAL;
4355
4356 if (ret < 0)
4357 goto out;
4358
4359 size = 1 << hash->size_bits;
4360 for (i = 0; i < size; i++) {
4361 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4362 if (ftrace_lookup_ip(old_hash, entry->ip))
4363 continue;
4364 /*
4365 * The caller might want to do something special
4366 * for each function we find. We call the callback
4367 * to give the caller an opportunity to do so.
4368 */
4369 if (probe_ops->init) {
4370 ret = probe_ops->init(probe_ops, tr,
4371 entry->ip, data,
4372 &probe->data);
4373 if (ret < 0) {
4374 if (probe_ops->free && count)
4375 probe_ops->free(probe_ops, tr,
4376 0, probe->data);
4377 probe->data = NULL;
4378 goto out;
4379 }
4380 }
4381 count++;
4382 }
4383 }
4384
4385 mutex_lock(&ftrace_lock);
4386
4387 if (!count) {
4388 /* Nothing was added? */
4389 ret = -EINVAL;
4390 goto out_unlock;
4391 }
4392
4393 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4394 hash, 1);
4395 if (ret < 0)
4396 goto err_unlock;
4397
4398 /* One ref for each new function traced */
4399 probe->ref += count;
4400
4401 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4402 ret = ftrace_startup(&probe->ops, 0);
4403
4404 out_unlock:
4405 mutex_unlock(&ftrace_lock);
4406
4407 if (!ret)
4408 ret = count;
4409 out:
4410 mutex_unlock(&probe->ops.func_hash->regex_lock);
4411 free_ftrace_hash(hash);
4412
4413 release_probe(probe);
4414
4415 return ret;
4416
4417 err_unlock:
4418 if (!probe_ops->free || !count)
4419 goto out_unlock;
4420
4421 /* Failed to do the move, need to call the free functions */
4422 for (i = 0; i < size; i++) {
4423 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4424 if (ftrace_lookup_ip(old_hash, entry->ip))
4425 continue;
4426 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4427 }
4428 }
4429 goto out_unlock;
4430}
4431
4432int
4433unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4434 struct ftrace_probe_ops *probe_ops)
4435{
4436 struct ftrace_ops_hash old_hash_ops;
4437 struct ftrace_func_entry *entry;
4438 struct ftrace_func_probe *probe;
4439 struct ftrace_glob func_g;
4440 struct ftrace_hash **orig_hash;
4441 struct ftrace_hash *old_hash;
4442 struct ftrace_hash *hash = NULL;
4443 struct hlist_node *tmp;
4444 struct hlist_head hhd;
4445 char str[KSYM_SYMBOL_LEN];
4446 int count = 0;
4447 int i, ret = -ENODEV;
4448 int size;
4449
4450 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4451 func_g.search = NULL;
4452 else {
4453 int not;
4454
4455 func_g.type = filter_parse_regex(glob, strlen(glob),
4456 &func_g.search, ¬);
4457 func_g.len = strlen(func_g.search);
4458
4459 /* we do not support '!' for function probes */
4460 if (WARN_ON(not))
4461 return -EINVAL;
4462 }
4463
4464 mutex_lock(&ftrace_lock);
4465 /* Check if the probe_ops is already registered */
4466 list_for_each_entry(probe, &tr->func_probes, list) {
4467 if (probe->probe_ops == probe_ops)
4468 break;
4469 }
4470 if (&probe->list == &tr->func_probes)
4471 goto err_unlock_ftrace;
4472
4473 ret = -EINVAL;
4474 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4475 goto err_unlock_ftrace;
4476
4477 acquire_probe_locked(probe);
4478
4479 mutex_unlock(&ftrace_lock);
4480
4481 mutex_lock(&probe->ops.func_hash->regex_lock);
4482
4483 orig_hash = &probe->ops.func_hash->filter_hash;
4484 old_hash = *orig_hash;
4485
4486 if (ftrace_hash_empty(old_hash))
4487 goto out_unlock;
4488
4489 old_hash_ops.filter_hash = old_hash;
4490 /* Probes only have filters */
4491 old_hash_ops.notrace_hash = NULL;
4492
4493 ret = -ENOMEM;
4494 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4495 if (!hash)
4496 goto out_unlock;
4497
4498 INIT_HLIST_HEAD(&hhd);
4499
4500 size = 1 << hash->size_bits;
4501 for (i = 0; i < size; i++) {
4502 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4503
4504 if (func_g.search) {
4505 kallsyms_lookup(entry->ip, NULL, NULL,
4506 NULL, str);
4507 if (!ftrace_match(str, &func_g))
4508 continue;
4509 }
4510 count++;
4511 remove_hash_entry(hash, entry);
4512 hlist_add_head(&entry->hlist, &hhd);
4513 }
4514 }
4515
4516 /* Nothing found? */
4517 if (!count) {
4518 ret = -EINVAL;
4519 goto out_unlock;
4520 }
4521
4522 mutex_lock(&ftrace_lock);
4523
4524 WARN_ON(probe->ref < count);
4525
4526 probe->ref -= count;
4527
4528 if (ftrace_hash_empty(hash))
4529 ftrace_shutdown(&probe->ops, 0);
4530
4531 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4532 hash, 1);
4533
4534 /* still need to update the function call sites */
4535 if (ftrace_enabled && !ftrace_hash_empty(hash))
4536 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4537 &old_hash_ops);
4538 synchronize_sched();
4539
4540 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4541 hlist_del(&entry->hlist);
4542 if (probe_ops->free)
4543 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4544 kfree(entry);
4545 }
4546 mutex_unlock(&ftrace_lock);
4547
4548 out_unlock:
4549 mutex_unlock(&probe->ops.func_hash->regex_lock);
4550 free_ftrace_hash(hash);
4551
4552 release_probe(probe);
4553
4554 return ret;
4555
4556 err_unlock_ftrace:
4557 mutex_unlock(&ftrace_lock);
4558 return ret;
4559}
4560
4561void clear_ftrace_function_probes(struct trace_array *tr)
4562{
4563 struct ftrace_func_probe *probe, *n;
4564
4565 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4566 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4567}
4568
4569static LIST_HEAD(ftrace_commands);
4570static DEFINE_MUTEX(ftrace_cmd_mutex);
4571
4572/*
4573 * Currently we only register ftrace commands from __init, so mark this
4574 * __init too.
4575 */
4576__init int register_ftrace_command(struct ftrace_func_command *cmd)
4577{
4578 struct ftrace_func_command *p;
4579 int ret = 0;
4580
4581 mutex_lock(&ftrace_cmd_mutex);
4582 list_for_each_entry(p, &ftrace_commands, list) {
4583 if (strcmp(cmd->name, p->name) == 0) {
4584 ret = -EBUSY;
4585 goto out_unlock;
4586 }
4587 }
4588 list_add(&cmd->list, &ftrace_commands);
4589 out_unlock:
4590 mutex_unlock(&ftrace_cmd_mutex);
4591
4592 return ret;
4593}
4594
4595/*
4596 * Currently we only unregister ftrace commands from __init, so mark
4597 * this __init too.
4598 */
4599__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4600{
4601 struct ftrace_func_command *p, *n;
4602 int ret = -ENODEV;
4603
4604 mutex_lock(&ftrace_cmd_mutex);
4605 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4606 if (strcmp(cmd->name, p->name) == 0) {
4607 ret = 0;
4608 list_del_init(&p->list);
4609 goto out_unlock;
4610 }
4611 }
4612 out_unlock:
4613 mutex_unlock(&ftrace_cmd_mutex);
4614
4615 return ret;
4616}
4617
4618static int ftrace_process_regex(struct ftrace_iterator *iter,
4619 char *buff, int len, int enable)
4620{
4621 struct ftrace_hash *hash = iter->hash;
4622 struct trace_array *tr = iter->ops->private;
4623 char *func, *command, *next = buff;
4624 struct ftrace_func_command *p;
4625 int ret = -EINVAL;
4626
4627 func = strsep(&next, ":");
4628
4629 if (!next) {
4630 ret = ftrace_match_records(hash, func, len);
4631 if (!ret)
4632 ret = -EINVAL;
4633 if (ret < 0)
4634 return ret;
4635 return 0;
4636 }
4637
4638 /* command found */
4639
4640 command = strsep(&next, ":");
4641
4642 mutex_lock(&ftrace_cmd_mutex);
4643 list_for_each_entry(p, &ftrace_commands, list) {
4644 if (strcmp(p->name, command) == 0) {
4645 ret = p->func(tr, hash, func, command, next, enable);
4646 goto out_unlock;
4647 }
4648 }
4649 out_unlock:
4650 mutex_unlock(&ftrace_cmd_mutex);
4651
4652 return ret;
4653}
4654
4655static ssize_t
4656ftrace_regex_write(struct file *file, const char __user *ubuf,
4657 size_t cnt, loff_t *ppos, int enable)
4658{
4659 struct ftrace_iterator *iter;
4660 struct trace_parser *parser;
4661 ssize_t ret, read;
4662
4663 if (!cnt)
4664 return 0;
4665
4666 if (file->f_mode & FMODE_READ) {
4667 struct seq_file *m = file->private_data;
4668 iter = m->private;
4669 } else
4670 iter = file->private_data;
4671
4672 if (unlikely(ftrace_disabled))
4673 return -ENODEV;
4674
4675 /* iter->hash is a local copy, so we don't need regex_lock */
4676
4677 parser = &iter->parser;
4678 read = trace_get_user(parser, ubuf, cnt, ppos);
4679
4680 if (read >= 0 && trace_parser_loaded(parser) &&
4681 !trace_parser_cont(parser)) {
4682 ret = ftrace_process_regex(iter, parser->buffer,
4683 parser->idx, enable);
4684 trace_parser_clear(parser);
4685 if (ret < 0)
4686 goto out;
4687 }
4688
4689 ret = read;
4690 out:
4691 return ret;
4692}
4693
4694ssize_t
4695ftrace_filter_write(struct file *file, const char __user *ubuf,
4696 size_t cnt, loff_t *ppos)
4697{
4698 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4699}
4700
4701ssize_t
4702ftrace_notrace_write(struct file *file, const char __user *ubuf,
4703 size_t cnt, loff_t *ppos)
4704{
4705 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4706}
4707
4708static int
4709ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4710{
4711 struct ftrace_func_entry *entry;
4712
4713 if (!ftrace_location(ip))
4714 return -EINVAL;
4715
4716 if (remove) {
4717 entry = ftrace_lookup_ip(hash, ip);
4718 if (!entry)
4719 return -ENOENT;
4720 free_hash_entry(hash, entry);
4721 return 0;
4722 }
4723
4724 return add_hash_entry(hash, ip);
4725}
4726
4727static int
4728ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4729 unsigned long ip, int remove, int reset, int enable)
4730{
4731 struct ftrace_hash **orig_hash;
4732 struct ftrace_hash *hash;
4733 int ret;
4734
4735 if (unlikely(ftrace_disabled))
4736 return -ENODEV;
4737
4738 mutex_lock(&ops->func_hash->regex_lock);
4739
4740 if (enable)
4741 orig_hash = &ops->func_hash->filter_hash;
4742 else
4743 orig_hash = &ops->func_hash->notrace_hash;
4744
4745 if (reset)
4746 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4747 else
4748 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4749
4750 if (!hash) {
4751 ret = -ENOMEM;
4752 goto out_regex_unlock;
4753 }
4754
4755 if (buf && !ftrace_match_records(hash, buf, len)) {
4756 ret = -EINVAL;
4757 goto out_regex_unlock;
4758 }
4759 if (ip) {
4760 ret = ftrace_match_addr(hash, ip, remove);
4761 if (ret < 0)
4762 goto out_regex_unlock;
4763 }
4764
4765 mutex_lock(&ftrace_lock);
4766 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4767 mutex_unlock(&ftrace_lock);
4768
4769 out_regex_unlock:
4770 mutex_unlock(&ops->func_hash->regex_lock);
4771
4772 free_ftrace_hash(hash);
4773 return ret;
4774}
4775
4776static int
4777ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4778 int reset, int enable)
4779{
4780 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4781}
4782
4783/**
4784 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4785 * @ops - the ops to set the filter with
4786 * @ip - the address to add to or remove from the filter.
4787 * @remove - non zero to remove the ip from the filter
4788 * @reset - non zero to reset all filters before applying this filter.
4789 *
4790 * Filters denote which functions should be enabled when tracing is enabled
4791 * If @ip is NULL, it failes to update filter.
4792 */
4793int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4794 int remove, int reset)
4795{
4796 ftrace_ops_init(ops);
4797 return ftrace_set_addr(ops, ip, remove, reset, 1);
4798}
4799EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4800
4801/**
4802 * ftrace_ops_set_global_filter - setup ops to use global filters
4803 * @ops - the ops which will use the global filters
4804 *
4805 * ftrace users who need global function trace filtering should call this.
4806 * It can set the global filter only if ops were not initialized before.
4807 */
4808void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4809{
4810 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4811 return;
4812
4813 ftrace_ops_init(ops);
4814 ops->func_hash = &global_ops.local_hash;
4815}
4816EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4817
4818static int
4819ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4820 int reset, int enable)
4821{
4822 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4823}
4824
4825/**
4826 * ftrace_set_filter - set a function to filter on in ftrace
4827 * @ops - the ops to set the filter with
4828 * @buf - the string that holds the function filter text.
4829 * @len - the length of the string.
4830 * @reset - non zero to reset all filters before applying this filter.
4831 *
4832 * Filters denote which functions should be enabled when tracing is enabled.
4833 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4834 */
4835int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4836 int len, int reset)
4837{
4838 ftrace_ops_init(ops);
4839 return ftrace_set_regex(ops, buf, len, reset, 1);
4840}
4841EXPORT_SYMBOL_GPL(ftrace_set_filter);
4842
4843/**
4844 * ftrace_set_notrace - set a function to not trace in ftrace
4845 * @ops - the ops to set the notrace filter with
4846 * @buf - the string that holds the function notrace text.
4847 * @len - the length of the string.
4848 * @reset - non zero to reset all filters before applying this filter.
4849 *
4850 * Notrace Filters denote which functions should not be enabled when tracing
4851 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4852 * for tracing.
4853 */
4854int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4855 int len, int reset)
4856{
4857 ftrace_ops_init(ops);
4858 return ftrace_set_regex(ops, buf, len, reset, 0);
4859}
4860EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4861/**
4862 * ftrace_set_global_filter - set a function to filter on with global tracers
4863 * @buf - the string that holds the function filter text.
4864 * @len - the length of the string.
4865 * @reset - non zero to reset all filters before applying this filter.
4866 *
4867 * Filters denote which functions should be enabled when tracing is enabled.
4868 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4869 */
4870void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4871{
4872 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4873}
4874EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4875
4876/**
4877 * ftrace_set_global_notrace - set a function to not trace with global tracers
4878 * @buf - the string that holds the function notrace text.
4879 * @len - the length of the string.
4880 * @reset - non zero to reset all filters before applying this filter.
4881 *
4882 * Notrace Filters denote which functions should not be enabled when tracing
4883 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4884 * for tracing.
4885 */
4886void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4887{
4888 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4889}
4890EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4891
4892/*
4893 * command line interface to allow users to set filters on boot up.
4894 */
4895#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4896static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4897static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4898
4899/* Used by function selftest to not test if filter is set */
4900bool ftrace_filter_param __initdata;
4901
4902static int __init set_ftrace_notrace(char *str)
4903{
4904 ftrace_filter_param = true;
4905 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4906 return 1;
4907}
4908__setup("ftrace_notrace=", set_ftrace_notrace);
4909
4910static int __init set_ftrace_filter(char *str)
4911{
4912 ftrace_filter_param = true;
4913 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4914 return 1;
4915}
4916__setup("ftrace_filter=", set_ftrace_filter);
4917
4918#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4919static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4920static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4921static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4922
4923static int __init set_graph_function(char *str)
4924{
4925 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4926 return 1;
4927}
4928__setup("ftrace_graph_filter=", set_graph_function);
4929
4930static int __init set_graph_notrace_function(char *str)
4931{
4932 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4933 return 1;
4934}
4935__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4936
4937static int __init set_graph_max_depth_function(char *str)
4938{
4939 if (!str)
4940 return 0;
4941 fgraph_max_depth = simple_strtoul(str, NULL, 0);
4942 return 1;
4943}
4944__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4945
4946static void __init set_ftrace_early_graph(char *buf, int enable)
4947{
4948 int ret;
4949 char *func;
4950 struct ftrace_hash *hash;
4951
4952 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4953 if (WARN_ON(!hash))
4954 return;
4955
4956 while (buf) {
4957 func = strsep(&buf, ",");
4958 /* we allow only one expression at a time */
4959 ret = ftrace_graph_set_hash(hash, func);
4960 if (ret)
4961 printk(KERN_DEBUG "ftrace: function %s not "
4962 "traceable\n", func);
4963 }
4964
4965 if (enable)
4966 ftrace_graph_hash = hash;
4967 else
4968 ftrace_graph_notrace_hash = hash;
4969}
4970#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4971
4972void __init
4973ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4974{
4975 char *func;
4976
4977 ftrace_ops_init(ops);
4978
4979 while (buf) {
4980 func = strsep(&buf, ",");
4981 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4982 }
4983}
4984
4985static void __init set_ftrace_early_filters(void)
4986{
4987 if (ftrace_filter_buf[0])
4988 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4989 if (ftrace_notrace_buf[0])
4990 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4991#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4992 if (ftrace_graph_buf[0])
4993 set_ftrace_early_graph(ftrace_graph_buf, 1);
4994 if (ftrace_graph_notrace_buf[0])
4995 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4996#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4997}
4998
4999int ftrace_regex_release(struct inode *inode, struct file *file)
5000{
5001 struct seq_file *m = (struct seq_file *)file->private_data;
5002 struct ftrace_iterator *iter;
5003 struct ftrace_hash **orig_hash;
5004 struct trace_parser *parser;
5005 int filter_hash;
5006 int ret;
5007
5008 if (file->f_mode & FMODE_READ) {
5009 iter = m->private;
5010 seq_release(inode, file);
5011 } else
5012 iter = file->private_data;
5013
5014 parser = &iter->parser;
5015 if (trace_parser_loaded(parser)) {
5016 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5017 }
5018
5019 trace_parser_put(parser);
5020
5021 mutex_lock(&iter->ops->func_hash->regex_lock);
5022
5023 if (file->f_mode & FMODE_WRITE) {
5024 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5025
5026 if (filter_hash) {
5027 orig_hash = &iter->ops->func_hash->filter_hash;
5028 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5029 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5030 } else
5031 orig_hash = &iter->ops->func_hash->notrace_hash;
5032
5033 mutex_lock(&ftrace_lock);
5034 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5035 iter->hash, filter_hash);
5036 mutex_unlock(&ftrace_lock);
5037 } else {
5038 /* For read only, the hash is the ops hash */
5039 iter->hash = NULL;
5040 }
5041
5042 mutex_unlock(&iter->ops->func_hash->regex_lock);
5043 free_ftrace_hash(iter->hash);
5044 kfree(iter);
5045
5046 return 0;
5047}
5048
5049static const struct file_operations ftrace_avail_fops = {
5050 .open = ftrace_avail_open,
5051 .read = seq_read,
5052 .llseek = seq_lseek,
5053 .release = seq_release_private,
5054};
5055
5056static const struct file_operations ftrace_enabled_fops = {
5057 .open = ftrace_enabled_open,
5058 .read = seq_read,
5059 .llseek = seq_lseek,
5060 .release = seq_release_private,
5061};
5062
5063static const struct file_operations ftrace_filter_fops = {
5064 .open = ftrace_filter_open,
5065 .read = seq_read,
5066 .write = ftrace_filter_write,
5067 .llseek = tracing_lseek,
5068 .release = ftrace_regex_release,
5069};
5070
5071static const struct file_operations ftrace_notrace_fops = {
5072 .open = ftrace_notrace_open,
5073 .read = seq_read,
5074 .write = ftrace_notrace_write,
5075 .llseek = tracing_lseek,
5076 .release = ftrace_regex_release,
5077};
5078
5079#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5080
5081static DEFINE_MUTEX(graph_lock);
5082
5083struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
5084struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
5085
5086enum graph_filter_type {
5087 GRAPH_FILTER_NOTRACE = 0,
5088 GRAPH_FILTER_FUNCTION,
5089};
5090
5091#define FTRACE_GRAPH_EMPTY ((void *)1)
5092
5093struct ftrace_graph_data {
5094 struct ftrace_hash *hash;
5095 struct ftrace_func_entry *entry;
5096 int idx; /* for hash table iteration */
5097 enum graph_filter_type type;
5098 struct ftrace_hash *new_hash;
5099 const struct seq_operations *seq_ops;
5100 struct trace_parser parser;
5101};
5102
5103static void *
5104__g_next(struct seq_file *m, loff_t *pos)
5105{
5106 struct ftrace_graph_data *fgd = m->private;
5107 struct ftrace_func_entry *entry = fgd->entry;
5108 struct hlist_head *head;
5109 int i, idx = fgd->idx;
5110
5111 if (*pos >= fgd->hash->count)
5112 return NULL;
5113
5114 if (entry) {
5115 hlist_for_each_entry_continue(entry, hlist) {
5116 fgd->entry = entry;
5117 return entry;
5118 }
5119
5120 idx++;
5121 }
5122
5123 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5124 head = &fgd->hash->buckets[i];
5125 hlist_for_each_entry(entry, head, hlist) {
5126 fgd->entry = entry;
5127 fgd->idx = i;
5128 return entry;
5129 }
5130 }
5131 return NULL;
5132}
5133
5134static void *
5135g_next(struct seq_file *m, void *v, loff_t *pos)
5136{
5137 (*pos)++;
5138 return __g_next(m, pos);
5139}
5140
5141static void *g_start(struct seq_file *m, loff_t *pos)
5142{
5143 struct ftrace_graph_data *fgd = m->private;
5144
5145 mutex_lock(&graph_lock);
5146
5147 if (fgd->type == GRAPH_FILTER_FUNCTION)
5148 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5149 lockdep_is_held(&graph_lock));
5150 else
5151 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5152 lockdep_is_held(&graph_lock));
5153
5154 /* Nothing, tell g_show to print all functions are enabled */
5155 if (ftrace_hash_empty(fgd->hash) && !*pos)
5156 return FTRACE_GRAPH_EMPTY;
5157
5158 fgd->idx = 0;
5159 fgd->entry = NULL;
5160 return __g_next(m, pos);
5161}
5162
5163static void g_stop(struct seq_file *m, void *p)
5164{
5165 mutex_unlock(&graph_lock);
5166}
5167
5168static int g_show(struct seq_file *m, void *v)
5169{
5170 struct ftrace_func_entry *entry = v;
5171
5172 if (!entry)
5173 return 0;
5174
5175 if (entry == FTRACE_GRAPH_EMPTY) {
5176 struct ftrace_graph_data *fgd = m->private;
5177
5178 if (fgd->type == GRAPH_FILTER_FUNCTION)
5179 seq_puts(m, "#### all functions enabled ####\n");
5180 else
5181 seq_puts(m, "#### no functions disabled ####\n");
5182 return 0;
5183 }
5184
5185 seq_printf(m, "%ps\n", (void *)entry->ip);
5186
5187 return 0;
5188}
5189
5190static const struct seq_operations ftrace_graph_seq_ops = {
5191 .start = g_start,
5192 .next = g_next,
5193 .stop = g_stop,
5194 .show = g_show,
5195};
5196
5197static int
5198__ftrace_graph_open(struct inode *inode, struct file *file,
5199 struct ftrace_graph_data *fgd)
5200{
5201 int ret = 0;
5202 struct ftrace_hash *new_hash = NULL;
5203
5204 if (file->f_mode & FMODE_WRITE) {
5205 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5206
5207 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5208 return -ENOMEM;
5209
5210 if (file->f_flags & O_TRUNC)
5211 new_hash = alloc_ftrace_hash(size_bits);
5212 else
5213 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5214 fgd->hash);
5215 if (!new_hash) {
5216 ret = -ENOMEM;
5217 goto out;
5218 }
5219 }
5220
5221 if (file->f_mode & FMODE_READ) {
5222 ret = seq_open(file, &ftrace_graph_seq_ops);
5223 if (!ret) {
5224 struct seq_file *m = file->private_data;
5225 m->private = fgd;
5226 } else {
5227 /* Failed */
5228 free_ftrace_hash(new_hash);
5229 new_hash = NULL;
5230 }
5231 } else
5232 file->private_data = fgd;
5233
5234out:
5235 if (ret < 0 && file->f_mode & FMODE_WRITE)
5236 trace_parser_put(&fgd->parser);
5237
5238 fgd->new_hash = new_hash;
5239
5240 /*
5241 * All uses of fgd->hash must be taken with the graph_lock
5242 * held. The graph_lock is going to be released, so force
5243 * fgd->hash to be reinitialized when it is taken again.
5244 */
5245 fgd->hash = NULL;
5246
5247 return ret;
5248}
5249
5250static int
5251ftrace_graph_open(struct inode *inode, struct file *file)
5252{
5253 struct ftrace_graph_data *fgd;
5254 int ret;
5255
5256 if (unlikely(ftrace_disabled))
5257 return -ENODEV;
5258
5259 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5260 if (fgd == NULL)
5261 return -ENOMEM;
5262
5263 mutex_lock(&graph_lock);
5264
5265 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5266 lockdep_is_held(&graph_lock));
5267 fgd->type = GRAPH_FILTER_FUNCTION;
5268 fgd->seq_ops = &ftrace_graph_seq_ops;
5269
5270 ret = __ftrace_graph_open(inode, file, fgd);
5271 if (ret < 0)
5272 kfree(fgd);
5273
5274 mutex_unlock(&graph_lock);
5275 return ret;
5276}
5277
5278static int
5279ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5280{
5281 struct ftrace_graph_data *fgd;
5282 int ret;
5283
5284 if (unlikely(ftrace_disabled))
5285 return -ENODEV;
5286
5287 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5288 if (fgd == NULL)
5289 return -ENOMEM;
5290
5291 mutex_lock(&graph_lock);
5292
5293 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5294 lockdep_is_held(&graph_lock));
5295 fgd->type = GRAPH_FILTER_NOTRACE;
5296 fgd->seq_ops = &ftrace_graph_seq_ops;
5297
5298 ret = __ftrace_graph_open(inode, file, fgd);
5299 if (ret < 0)
5300 kfree(fgd);
5301
5302 mutex_unlock(&graph_lock);
5303 return ret;
5304}
5305
5306static int
5307ftrace_graph_release(struct inode *inode, struct file *file)
5308{
5309 struct ftrace_graph_data *fgd;
5310 struct ftrace_hash *old_hash, *new_hash;
5311 struct trace_parser *parser;
5312 int ret = 0;
5313
5314 if (file->f_mode & FMODE_READ) {
5315 struct seq_file *m = file->private_data;
5316
5317 fgd = m->private;
5318 seq_release(inode, file);
5319 } else {
5320 fgd = file->private_data;
5321 }
5322
5323
5324 if (file->f_mode & FMODE_WRITE) {
5325
5326 parser = &fgd->parser;
5327
5328 if (trace_parser_loaded((parser))) {
5329 ret = ftrace_graph_set_hash(fgd->new_hash,
5330 parser->buffer);
5331 }
5332
5333 trace_parser_put(parser);
5334
5335 new_hash = __ftrace_hash_move(fgd->new_hash);
5336 if (!new_hash) {
5337 ret = -ENOMEM;
5338 goto out;
5339 }
5340
5341 mutex_lock(&graph_lock);
5342
5343 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5344 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5345 lockdep_is_held(&graph_lock));
5346 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5347 } else {
5348 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5349 lockdep_is_held(&graph_lock));
5350 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5351 }
5352
5353 mutex_unlock(&graph_lock);
5354
5355 /* Wait till all users are no longer using the old hash */
5356 synchronize_sched();
5357
5358 free_ftrace_hash(old_hash);
5359 }
5360
5361 out:
5362 free_ftrace_hash(fgd->new_hash);
5363 kfree(fgd);
5364
5365 return ret;
5366}
5367
5368static int
5369ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5370{
5371 struct ftrace_glob func_g;
5372 struct dyn_ftrace *rec;
5373 struct ftrace_page *pg;
5374 struct ftrace_func_entry *entry;
5375 int fail = 1;
5376 int not;
5377
5378 /* decode regex */
5379 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5380 &func_g.search, ¬);
5381
5382 func_g.len = strlen(func_g.search);
5383
5384 mutex_lock(&ftrace_lock);
5385
5386 if (unlikely(ftrace_disabled)) {
5387 mutex_unlock(&ftrace_lock);
5388 return -ENODEV;
5389 }
5390
5391 do_for_each_ftrace_rec(pg, rec) {
5392
5393 if (rec->flags & FTRACE_FL_DISABLED)
5394 continue;
5395
5396 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5397 entry = ftrace_lookup_ip(hash, rec->ip);
5398
5399 if (!not) {
5400 fail = 0;
5401
5402 if (entry)
5403 continue;
5404 if (add_hash_entry(hash, rec->ip) < 0)
5405 goto out;
5406 } else {
5407 if (entry) {
5408 free_hash_entry(hash, entry);
5409 fail = 0;
5410 }
5411 }
5412 }
5413 } while_for_each_ftrace_rec();
5414out:
5415 mutex_unlock(&ftrace_lock);
5416
5417 if (fail)
5418 return -EINVAL;
5419
5420 return 0;
5421}
5422
5423static ssize_t
5424ftrace_graph_write(struct file *file, const char __user *ubuf,
5425 size_t cnt, loff_t *ppos)
5426{
5427 ssize_t read, ret = 0;
5428 struct ftrace_graph_data *fgd = file->private_data;
5429 struct trace_parser *parser;
5430
5431 if (!cnt)
5432 return 0;
5433
5434 /* Read mode uses seq functions */
5435 if (file->f_mode & FMODE_READ) {
5436 struct seq_file *m = file->private_data;
5437 fgd = m->private;
5438 }
5439
5440 parser = &fgd->parser;
5441
5442 read = trace_get_user(parser, ubuf, cnt, ppos);
5443
5444 if (read >= 0 && trace_parser_loaded(parser) &&
5445 !trace_parser_cont(parser)) {
5446
5447 ret = ftrace_graph_set_hash(fgd->new_hash,
5448 parser->buffer);
5449 trace_parser_clear(parser);
5450 }
5451
5452 if (!ret)
5453 ret = read;
5454
5455 return ret;
5456}
5457
5458static const struct file_operations ftrace_graph_fops = {
5459 .open = ftrace_graph_open,
5460 .read = seq_read,
5461 .write = ftrace_graph_write,
5462 .llseek = tracing_lseek,
5463 .release = ftrace_graph_release,
5464};
5465
5466static const struct file_operations ftrace_graph_notrace_fops = {
5467 .open = ftrace_graph_notrace_open,
5468 .read = seq_read,
5469 .write = ftrace_graph_write,
5470 .llseek = tracing_lseek,
5471 .release = ftrace_graph_release,
5472};
5473#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5474
5475void ftrace_create_filter_files(struct ftrace_ops *ops,
5476 struct dentry *parent)
5477{
5478
5479 trace_create_file("set_ftrace_filter", 0644, parent,
5480 ops, &ftrace_filter_fops);
5481
5482 trace_create_file("set_ftrace_notrace", 0644, parent,
5483 ops, &ftrace_notrace_fops);
5484}
5485
5486/*
5487 * The name "destroy_filter_files" is really a misnomer. Although
5488 * in the future, it may actualy delete the files, but this is
5489 * really intended to make sure the ops passed in are disabled
5490 * and that when this function returns, the caller is free to
5491 * free the ops.
5492 *
5493 * The "destroy" name is only to match the "create" name that this
5494 * should be paired with.
5495 */
5496void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5497{
5498 mutex_lock(&ftrace_lock);
5499 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5500 ftrace_shutdown(ops, 0);
5501 ops->flags |= FTRACE_OPS_FL_DELETED;
5502 mutex_unlock(&ftrace_lock);
5503}
5504
5505static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5506{
5507
5508 trace_create_file("available_filter_functions", 0444,
5509 d_tracer, NULL, &ftrace_avail_fops);
5510
5511 trace_create_file("enabled_functions", 0444,
5512 d_tracer, NULL, &ftrace_enabled_fops);
5513
5514 ftrace_create_filter_files(&global_ops, d_tracer);
5515
5516#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5517 trace_create_file("set_graph_function", 0644, d_tracer,
5518 NULL,
5519 &ftrace_graph_fops);
5520 trace_create_file("set_graph_notrace", 0644, d_tracer,
5521 NULL,
5522 &ftrace_graph_notrace_fops);
5523#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5524
5525 return 0;
5526}
5527
5528static int ftrace_cmp_ips(const void *a, const void *b)
5529{
5530 const unsigned long *ipa = a;
5531 const unsigned long *ipb = b;
5532
5533 if (*ipa > *ipb)
5534 return 1;
5535 if (*ipa < *ipb)
5536 return -1;
5537 return 0;
5538}
5539
5540static int ftrace_process_locs(struct module *mod,
5541 unsigned long *start,
5542 unsigned long *end)
5543{
5544 struct ftrace_page *start_pg;
5545 struct ftrace_page *pg;
5546 struct dyn_ftrace *rec;
5547 unsigned long count;
5548 unsigned long *p;
5549 unsigned long addr;
5550 unsigned long flags = 0; /* Shut up gcc */
5551 int ret = -ENOMEM;
5552
5553 count = end - start;
5554
5555 if (!count)
5556 return 0;
5557
5558 sort(start, count, sizeof(*start),
5559 ftrace_cmp_ips, NULL);
5560
5561 start_pg = ftrace_allocate_pages(count);
5562 if (!start_pg)
5563 return -ENOMEM;
5564
5565 mutex_lock(&ftrace_lock);
5566
5567 /*
5568 * Core and each module needs their own pages, as
5569 * modules will free them when they are removed.
5570 * Force a new page to be allocated for modules.
5571 */
5572 if (!mod) {
5573 WARN_ON(ftrace_pages || ftrace_pages_start);
5574 /* First initialization */
5575 ftrace_pages = ftrace_pages_start = start_pg;
5576 } else {
5577 if (!ftrace_pages)
5578 goto out;
5579
5580 if (WARN_ON(ftrace_pages->next)) {
5581 /* Hmm, we have free pages? */
5582 while (ftrace_pages->next)
5583 ftrace_pages = ftrace_pages->next;
5584 }
5585
5586 ftrace_pages->next = start_pg;
5587 }
5588
5589 p = start;
5590 pg = start_pg;
5591 while (p < end) {
5592 addr = ftrace_call_adjust(*p++);
5593 /*
5594 * Some architecture linkers will pad between
5595 * the different mcount_loc sections of different
5596 * object files to satisfy alignments.
5597 * Skip any NULL pointers.
5598 */
5599 if (!addr)
5600 continue;
5601
5602 if (pg->index == pg->size) {
5603 /* We should have allocated enough */
5604 if (WARN_ON(!pg->next))
5605 break;
5606 pg = pg->next;
5607 }
5608
5609 rec = &pg->records[pg->index++];
5610 rec->ip = addr;
5611 }
5612
5613 /* We should have used all pages */
5614 WARN_ON(pg->next);
5615
5616 /* Assign the last page to ftrace_pages */
5617 ftrace_pages = pg;
5618
5619 /*
5620 * We only need to disable interrupts on start up
5621 * because we are modifying code that an interrupt
5622 * may execute, and the modification is not atomic.
5623 * But for modules, nothing runs the code we modify
5624 * until we are finished with it, and there's no
5625 * reason to cause large interrupt latencies while we do it.
5626 */
5627 if (!mod)
5628 local_irq_save(flags);
5629 ftrace_update_code(mod, start_pg);
5630 if (!mod)
5631 local_irq_restore(flags);
5632 ret = 0;
5633 out:
5634 mutex_unlock(&ftrace_lock);
5635
5636 return ret;
5637}
5638
5639struct ftrace_mod_func {
5640 struct list_head list;
5641 char *name;
5642 unsigned long ip;
5643 unsigned int size;
5644};
5645
5646struct ftrace_mod_map {
5647 struct rcu_head rcu;
5648 struct list_head list;
5649 struct module *mod;
5650 unsigned long start_addr;
5651 unsigned long end_addr;
5652 struct list_head funcs;
5653 unsigned int num_funcs;
5654};
5655
5656#ifdef CONFIG_MODULES
5657
5658#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5659
5660static LIST_HEAD(ftrace_mod_maps);
5661
5662static int referenced_filters(struct dyn_ftrace *rec)
5663{
5664 struct ftrace_ops *ops;
5665 int cnt = 0;
5666
5667 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5668 if (ops_references_rec(ops, rec))
5669 cnt++;
5670 }
5671
5672 return cnt;
5673}
5674
5675static void
5676clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5677{
5678 struct ftrace_func_entry *entry;
5679 struct dyn_ftrace *rec;
5680 int i;
5681
5682 if (ftrace_hash_empty(hash))
5683 return;
5684
5685 for (i = 0; i < pg->index; i++) {
5686 rec = &pg->records[i];
5687 entry = __ftrace_lookup_ip(hash, rec->ip);
5688 /*
5689 * Do not allow this rec to match again.
5690 * Yeah, it may waste some memory, but will be removed
5691 * if/when the hash is modified again.
5692 */
5693 if (entry)
5694 entry->ip = 0;
5695 }
5696}
5697
5698/* Clear any records from hashs */
5699static void clear_mod_from_hashes(struct ftrace_page *pg)
5700{
5701 struct trace_array *tr;
5702
5703 mutex_lock(&trace_types_lock);
5704 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5705 if (!tr->ops || !tr->ops->func_hash)
5706 continue;
5707 mutex_lock(&tr->ops->func_hash->regex_lock);
5708 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5709 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5710 mutex_unlock(&tr->ops->func_hash->regex_lock);
5711 }
5712 mutex_unlock(&trace_types_lock);
5713}
5714
5715static void ftrace_free_mod_map(struct rcu_head *rcu)
5716{
5717 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5718 struct ftrace_mod_func *mod_func;
5719 struct ftrace_mod_func *n;
5720
5721 /* All the contents of mod_map are now not visible to readers */
5722 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5723 kfree(mod_func->name);
5724 list_del(&mod_func->list);
5725 kfree(mod_func);
5726 }
5727
5728 kfree(mod_map);
5729}
5730
5731void ftrace_release_mod(struct module *mod)
5732{
5733 struct ftrace_mod_map *mod_map;
5734 struct ftrace_mod_map *n;
5735 struct dyn_ftrace *rec;
5736 struct ftrace_page **last_pg;
5737 struct ftrace_page *tmp_page = NULL;
5738 struct ftrace_page *pg;
5739 int order;
5740
5741 mutex_lock(&ftrace_lock);
5742
5743 if (ftrace_disabled)
5744 goto out_unlock;
5745
5746 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5747 if (mod_map->mod == mod) {
5748 list_del_rcu(&mod_map->list);
5749 call_rcu_sched(&mod_map->rcu, ftrace_free_mod_map);
5750 break;
5751 }
5752 }
5753
5754 /*
5755 * Each module has its own ftrace_pages, remove
5756 * them from the list.
5757 */
5758 last_pg = &ftrace_pages_start;
5759 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5760 rec = &pg->records[0];
5761 if (within_module_core(rec->ip, mod) ||
5762 within_module_init(rec->ip, mod)) {
5763 /*
5764 * As core pages are first, the first
5765 * page should never be a module page.
5766 */
5767 if (WARN_ON(pg == ftrace_pages_start))
5768 goto out_unlock;
5769
5770 /* Check if we are deleting the last page */
5771 if (pg == ftrace_pages)
5772 ftrace_pages = next_to_ftrace_page(last_pg);
5773
5774 ftrace_update_tot_cnt -= pg->index;
5775 *last_pg = pg->next;
5776
5777 pg->next = tmp_page;
5778 tmp_page = pg;
5779 } else
5780 last_pg = &pg->next;
5781 }
5782 out_unlock:
5783 mutex_unlock(&ftrace_lock);
5784
5785 for (pg = tmp_page; pg; pg = tmp_page) {
5786
5787 /* Needs to be called outside of ftrace_lock */
5788 clear_mod_from_hashes(pg);
5789
5790 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5791 free_pages((unsigned long)pg->records, order);
5792 tmp_page = pg->next;
5793 kfree(pg);
5794 }
5795}
5796
5797void ftrace_module_enable(struct module *mod)
5798{
5799 struct dyn_ftrace *rec;
5800 struct ftrace_page *pg;
5801
5802 mutex_lock(&ftrace_lock);
5803
5804 if (ftrace_disabled)
5805 goto out_unlock;
5806
5807 /*
5808 * If the tracing is enabled, go ahead and enable the record.
5809 *
5810 * The reason not to enable the record immediatelly is the
5811 * inherent check of ftrace_make_nop/ftrace_make_call for
5812 * correct previous instructions. Making first the NOP
5813 * conversion puts the module to the correct state, thus
5814 * passing the ftrace_make_call check.
5815 *
5816 * We also delay this to after the module code already set the
5817 * text to read-only, as we now need to set it back to read-write
5818 * so that we can modify the text.
5819 */
5820 if (ftrace_start_up)
5821 ftrace_arch_code_modify_prepare();
5822
5823 do_for_each_ftrace_rec(pg, rec) {
5824 int cnt;
5825 /*
5826 * do_for_each_ftrace_rec() is a double loop.
5827 * module text shares the pg. If a record is
5828 * not part of this module, then skip this pg,
5829 * which the "break" will do.
5830 */
5831 if (!within_module_core(rec->ip, mod) &&
5832 !within_module_init(rec->ip, mod))
5833 break;
5834
5835 cnt = 0;
5836
5837 /*
5838 * When adding a module, we need to check if tracers are
5839 * currently enabled and if they are, and can trace this record,
5840 * we need to enable the module functions as well as update the
5841 * reference counts for those function records.
5842 */
5843 if (ftrace_start_up)
5844 cnt += referenced_filters(rec);
5845
5846 /* This clears FTRACE_FL_DISABLED */
5847 rec->flags = cnt;
5848
5849 if (ftrace_start_up && cnt) {
5850 int failed = __ftrace_replace_code(rec, 1);
5851 if (failed) {
5852 ftrace_bug(failed, rec);
5853 goto out_loop;
5854 }
5855 }
5856
5857 } while_for_each_ftrace_rec();
5858
5859 out_loop:
5860 if (ftrace_start_up)
5861 ftrace_arch_code_modify_post_process();
5862
5863 out_unlock:
5864 mutex_unlock(&ftrace_lock);
5865
5866 process_cached_mods(mod->name);
5867}
5868
5869void ftrace_module_init(struct module *mod)
5870{
5871 if (ftrace_disabled || !mod->num_ftrace_callsites)
5872 return;
5873
5874 ftrace_process_locs(mod, mod->ftrace_callsites,
5875 mod->ftrace_callsites + mod->num_ftrace_callsites);
5876}
5877
5878static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5879 struct dyn_ftrace *rec)
5880{
5881 struct ftrace_mod_func *mod_func;
5882 unsigned long symsize;
5883 unsigned long offset;
5884 char str[KSYM_SYMBOL_LEN];
5885 char *modname;
5886 const char *ret;
5887
5888 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
5889 if (!ret)
5890 return;
5891
5892 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
5893 if (!mod_func)
5894 return;
5895
5896 mod_func->name = kstrdup(str, GFP_KERNEL);
5897 if (!mod_func->name) {
5898 kfree(mod_func);
5899 return;
5900 }
5901
5902 mod_func->ip = rec->ip - offset;
5903 mod_func->size = symsize;
5904
5905 mod_map->num_funcs++;
5906
5907 list_add_rcu(&mod_func->list, &mod_map->funcs);
5908}
5909
5910static struct ftrace_mod_map *
5911allocate_ftrace_mod_map(struct module *mod,
5912 unsigned long start, unsigned long end)
5913{
5914 struct ftrace_mod_map *mod_map;
5915
5916 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
5917 if (!mod_map)
5918 return NULL;
5919
5920 mod_map->mod = mod;
5921 mod_map->start_addr = start;
5922 mod_map->end_addr = end;
5923 mod_map->num_funcs = 0;
5924
5925 INIT_LIST_HEAD_RCU(&mod_map->funcs);
5926
5927 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
5928
5929 return mod_map;
5930}
5931
5932static const char *
5933ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
5934 unsigned long addr, unsigned long *size,
5935 unsigned long *off, char *sym)
5936{
5937 struct ftrace_mod_func *found_func = NULL;
5938 struct ftrace_mod_func *mod_func;
5939
5940 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5941 if (addr >= mod_func->ip &&
5942 addr < mod_func->ip + mod_func->size) {
5943 found_func = mod_func;
5944 break;
5945 }
5946 }
5947
5948 if (found_func) {
5949 if (size)
5950 *size = found_func->size;
5951 if (off)
5952 *off = addr - found_func->ip;
5953 if (sym)
5954 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
5955
5956 return found_func->name;
5957 }
5958
5959 return NULL;
5960}
5961
5962const char *
5963ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
5964 unsigned long *off, char **modname, char *sym)
5965{
5966 struct ftrace_mod_map *mod_map;
5967 const char *ret = NULL;
5968
5969 /* mod_map is freed via call_rcu_sched() */
5970 preempt_disable();
5971 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5972 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
5973 if (ret) {
5974 if (modname)
5975 *modname = mod_map->mod->name;
5976 break;
5977 }
5978 }
5979 preempt_enable();
5980
5981 return ret;
5982}
5983
5984int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
5985 char *type, char *name,
5986 char *module_name, int *exported)
5987{
5988 struct ftrace_mod_map *mod_map;
5989 struct ftrace_mod_func *mod_func;
5990
5991 preempt_disable();
5992 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5993
5994 if (symnum >= mod_map->num_funcs) {
5995 symnum -= mod_map->num_funcs;
5996 continue;
5997 }
5998
5999 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6000 if (symnum > 1) {
6001 symnum--;
6002 continue;
6003 }
6004
6005 *value = mod_func->ip;
6006 *type = 'T';
6007 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6008 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6009 *exported = 1;
6010 preempt_enable();
6011 return 0;
6012 }
6013 WARN_ON(1);
6014 break;
6015 }
6016 preempt_enable();
6017 return -ERANGE;
6018}
6019
6020#else
6021static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6022 struct dyn_ftrace *rec) { }
6023static inline struct ftrace_mod_map *
6024allocate_ftrace_mod_map(struct module *mod,
6025 unsigned long start, unsigned long end)
6026{
6027 return NULL;
6028}
6029#endif /* CONFIG_MODULES */
6030
6031struct ftrace_init_func {
6032 struct list_head list;
6033 unsigned long ip;
6034};
6035
6036/* Clear any init ips from hashes */
6037static void
6038clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6039{
6040 struct ftrace_func_entry *entry;
6041
6042 if (ftrace_hash_empty(hash))
6043 return;
6044
6045 entry = __ftrace_lookup_ip(hash, func->ip);
6046
6047 /*
6048 * Do not allow this rec to match again.
6049 * Yeah, it may waste some memory, but will be removed
6050 * if/when the hash is modified again.
6051 */
6052 if (entry)
6053 entry->ip = 0;
6054}
6055
6056static void
6057clear_func_from_hashes(struct ftrace_init_func *func)
6058{
6059 struct trace_array *tr;
6060
6061 mutex_lock(&trace_types_lock);
6062 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6063 if (!tr->ops || !tr->ops->func_hash)
6064 continue;
6065 mutex_lock(&tr->ops->func_hash->regex_lock);
6066 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6067 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6068 mutex_unlock(&tr->ops->func_hash->regex_lock);
6069 }
6070 mutex_unlock(&trace_types_lock);
6071}
6072
6073static void add_to_clear_hash_list(struct list_head *clear_list,
6074 struct dyn_ftrace *rec)
6075{
6076 struct ftrace_init_func *func;
6077
6078 func = kmalloc(sizeof(*func), GFP_KERNEL);
6079 if (!func) {
6080 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6081 return;
6082 }
6083
6084 func->ip = rec->ip;
6085 list_add(&func->list, clear_list);
6086}
6087
6088void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6089{
6090 unsigned long start = (unsigned long)(start_ptr);
6091 unsigned long end = (unsigned long)(end_ptr);
6092 struct ftrace_page **last_pg = &ftrace_pages_start;
6093 struct ftrace_page *pg;
6094 struct dyn_ftrace *rec;
6095 struct dyn_ftrace key;
6096 struct ftrace_mod_map *mod_map = NULL;
6097 struct ftrace_init_func *func, *func_next;
6098 struct list_head clear_hash;
6099 int order;
6100
6101 INIT_LIST_HEAD(&clear_hash);
6102
6103 key.ip = start;
6104 key.flags = end; /* overload flags, as it is unsigned long */
6105
6106 mutex_lock(&ftrace_lock);
6107
6108 /*
6109 * If we are freeing module init memory, then check if
6110 * any tracer is active. If so, we need to save a mapping of
6111 * the module functions being freed with the address.
6112 */
6113 if (mod && ftrace_ops_list != &ftrace_list_end)
6114 mod_map = allocate_ftrace_mod_map(mod, start, end);
6115
6116 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6117 if (end < pg->records[0].ip ||
6118 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6119 continue;
6120 again:
6121 rec = bsearch(&key, pg->records, pg->index,
6122 sizeof(struct dyn_ftrace),
6123 ftrace_cmp_recs);
6124 if (!rec)
6125 continue;
6126
6127 /* rec will be cleared from hashes after ftrace_lock unlock */
6128 add_to_clear_hash_list(&clear_hash, rec);
6129
6130 if (mod_map)
6131 save_ftrace_mod_rec(mod_map, rec);
6132
6133 pg->index--;
6134 ftrace_update_tot_cnt--;
6135 if (!pg->index) {
6136 *last_pg = pg->next;
6137 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6138 free_pages((unsigned long)pg->records, order);
6139 kfree(pg);
6140 pg = container_of(last_pg, struct ftrace_page, next);
6141 if (!(*last_pg))
6142 ftrace_pages = pg;
6143 continue;
6144 }
6145 memmove(rec, rec + 1,
6146 (pg->index - (rec - pg->records)) * sizeof(*rec));
6147 /* More than one function may be in this block */
6148 goto again;
6149 }
6150 mutex_unlock(&ftrace_lock);
6151
6152 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6153 clear_func_from_hashes(func);
6154 kfree(func);
6155 }
6156}
6157
6158void __init ftrace_free_init_mem(void)
6159{
6160 void *start = (void *)(&__init_begin);
6161 void *end = (void *)(&__init_end);
6162
6163 ftrace_free_mem(NULL, start, end);
6164}
6165
6166void __init ftrace_init(void)
6167{
6168 extern unsigned long __start_mcount_loc[];
6169 extern unsigned long __stop_mcount_loc[];
6170 unsigned long count, flags;
6171 int ret;
6172
6173 local_irq_save(flags);
6174 ret = ftrace_dyn_arch_init();
6175 local_irq_restore(flags);
6176 if (ret)
6177 goto failed;
6178
6179 count = __stop_mcount_loc - __start_mcount_loc;
6180 if (!count) {
6181 pr_info("ftrace: No functions to be traced?\n");
6182 goto failed;
6183 }
6184
6185 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6186 count, count / ENTRIES_PER_PAGE + 1);
6187
6188 last_ftrace_enabled = ftrace_enabled = 1;
6189
6190 ret = ftrace_process_locs(NULL,
6191 __start_mcount_loc,
6192 __stop_mcount_loc);
6193
6194 set_ftrace_early_filters();
6195
6196 return;
6197 failed:
6198 ftrace_disabled = 1;
6199}
6200
6201/* Do nothing if arch does not support this */
6202void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6203{
6204}
6205
6206static void ftrace_update_trampoline(struct ftrace_ops *ops)
6207{
6208 arch_ftrace_update_trampoline(ops);
6209}
6210
6211void ftrace_init_trace_array(struct trace_array *tr)
6212{
6213 INIT_LIST_HEAD(&tr->func_probes);
6214 INIT_LIST_HEAD(&tr->mod_trace);
6215 INIT_LIST_HEAD(&tr->mod_notrace);
6216}
6217#else
6218
6219static struct ftrace_ops global_ops = {
6220 .func = ftrace_stub,
6221 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6222 FTRACE_OPS_FL_INITIALIZED |
6223 FTRACE_OPS_FL_PID,
6224};
6225
6226static int __init ftrace_nodyn_init(void)
6227{
6228 ftrace_enabled = 1;
6229 return 0;
6230}
6231core_initcall(ftrace_nodyn_init);
6232
6233static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6234static inline void ftrace_startup_enable(int command) { }
6235static inline void ftrace_startup_all(int command) { }
6236/* Keep as macros so we do not need to define the commands */
6237# define ftrace_startup(ops, command) \
6238 ({ \
6239 int ___ret = __register_ftrace_function(ops); \
6240 if (!___ret) \
6241 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
6242 ___ret; \
6243 })
6244# define ftrace_shutdown(ops, command) \
6245 ({ \
6246 int ___ret = __unregister_ftrace_function(ops); \
6247 if (!___ret) \
6248 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
6249 ___ret; \
6250 })
6251
6252# define ftrace_startup_sysctl() do { } while (0)
6253# define ftrace_shutdown_sysctl() do { } while (0)
6254
6255static inline int
6256ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
6257{
6258 return 1;
6259}
6260
6261static void ftrace_update_trampoline(struct ftrace_ops *ops)
6262{
6263}
6264
6265#endif /* CONFIG_DYNAMIC_FTRACE */
6266
6267__init void ftrace_init_global_array_ops(struct trace_array *tr)
6268{
6269 tr->ops = &global_ops;
6270 tr->ops->private = tr;
6271 ftrace_init_trace_array(tr);
6272}
6273
6274void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6275{
6276 /* If we filter on pids, update to use the pid function */
6277 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6278 if (WARN_ON(tr->ops->func != ftrace_stub))
6279 printk("ftrace ops had %pS for function\n",
6280 tr->ops->func);
6281 }
6282 tr->ops->func = func;
6283 tr->ops->private = tr;
6284}
6285
6286void ftrace_reset_array_ops(struct trace_array *tr)
6287{
6288 tr->ops->func = ftrace_stub;
6289}
6290
6291static inline void
6292__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6293 struct ftrace_ops *ignored, struct pt_regs *regs)
6294{
6295 struct ftrace_ops *op;
6296 int bit;
6297
6298 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6299 if (bit < 0)
6300 return;
6301
6302 /*
6303 * Some of the ops may be dynamically allocated,
6304 * they must be freed after a synchronize_sched().
6305 */
6306 preempt_disable_notrace();
6307
6308 do_for_each_ftrace_op(op, ftrace_ops_list) {
6309 /*
6310 * Check the following for each ops before calling their func:
6311 * if RCU flag is set, then rcu_is_watching() must be true
6312 * if PER_CPU is set, then ftrace_function_local_disable()
6313 * must be false
6314 * Otherwise test if the ip matches the ops filter
6315 *
6316 * If any of the above fails then the op->func() is not executed.
6317 */
6318 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6319 ftrace_ops_test(op, ip, regs)) {
6320 if (FTRACE_WARN_ON(!op->func)) {
6321 pr_warn("op=%p %pS\n", op, op);
6322 goto out;
6323 }
6324 op->func(ip, parent_ip, op, regs);
6325 }
6326 } while_for_each_ftrace_op(op);
6327out:
6328 preempt_enable_notrace();
6329 trace_clear_recursion(bit);
6330}
6331
6332/*
6333 * Some archs only support passing ip and parent_ip. Even though
6334 * the list function ignores the op parameter, we do not want any
6335 * C side effects, where a function is called without the caller
6336 * sending a third parameter.
6337 * Archs are to support both the regs and ftrace_ops at the same time.
6338 * If they support ftrace_ops, it is assumed they support regs.
6339 * If call backs want to use regs, they must either check for regs
6340 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6341 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6342 * An architecture can pass partial regs with ftrace_ops and still
6343 * set the ARCH_SUPPORTS_FTRACE_OPS.
6344 */
6345#if ARCH_SUPPORTS_FTRACE_OPS
6346static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6347 struct ftrace_ops *op, struct pt_regs *regs)
6348{
6349 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6350}
6351#else
6352static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6353{
6354 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6355}
6356#endif
6357
6358/*
6359 * If there's only one function registered but it does not support
6360 * recursion, needs RCU protection and/or requires per cpu handling, then
6361 * this function will be called by the mcount trampoline.
6362 */
6363static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6364 struct ftrace_ops *op, struct pt_regs *regs)
6365{
6366 int bit;
6367
6368 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6369 return;
6370
6371 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6372 if (bit < 0)
6373 return;
6374
6375 preempt_disable_notrace();
6376
6377 op->func(ip, parent_ip, op, regs);
6378
6379 preempt_enable_notrace();
6380 trace_clear_recursion(bit);
6381}
6382
6383/**
6384 * ftrace_ops_get_func - get the function a trampoline should call
6385 * @ops: the ops to get the function for
6386 *
6387 * Normally the mcount trampoline will call the ops->func, but there
6388 * are times that it should not. For example, if the ops does not
6389 * have its own recursion protection, then it should call the
6390 * ftrace_ops_assist_func() instead.
6391 *
6392 * Returns the function that the trampoline should call for @ops.
6393 */
6394ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6395{
6396 /*
6397 * If the function does not handle recursion, needs to be RCU safe,
6398 * or does per cpu logic, then we need to call the assist handler.
6399 */
6400 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6401 ops->flags & FTRACE_OPS_FL_RCU)
6402 return ftrace_ops_assist_func;
6403
6404 return ops->func;
6405}
6406
6407static void
6408ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6409 struct task_struct *prev, struct task_struct *next)
6410{
6411 struct trace_array *tr = data;
6412 struct trace_pid_list *pid_list;
6413
6414 pid_list = rcu_dereference_sched(tr->function_pids);
6415
6416 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6417 trace_ignore_this_task(pid_list, next));
6418}
6419
6420static void
6421ftrace_pid_follow_sched_process_fork(void *data,
6422 struct task_struct *self,
6423 struct task_struct *task)
6424{
6425 struct trace_pid_list *pid_list;
6426 struct trace_array *tr = data;
6427
6428 pid_list = rcu_dereference_sched(tr->function_pids);
6429 trace_filter_add_remove_task(pid_list, self, task);
6430}
6431
6432static void
6433ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6434{
6435 struct trace_pid_list *pid_list;
6436 struct trace_array *tr = data;
6437
6438 pid_list = rcu_dereference_sched(tr->function_pids);
6439 trace_filter_add_remove_task(pid_list, NULL, task);
6440}
6441
6442void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6443{
6444 if (enable) {
6445 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6446 tr);
6447 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6448 tr);
6449 } else {
6450 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6451 tr);
6452 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6453 tr);
6454 }
6455}
6456
6457static void clear_ftrace_pids(struct trace_array *tr)
6458{
6459 struct trace_pid_list *pid_list;
6460 int cpu;
6461
6462 pid_list = rcu_dereference_protected(tr->function_pids,
6463 lockdep_is_held(&ftrace_lock));
6464 if (!pid_list)
6465 return;
6466
6467 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6468
6469 for_each_possible_cpu(cpu)
6470 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6471
6472 rcu_assign_pointer(tr->function_pids, NULL);
6473
6474 /* Wait till all users are no longer using pid filtering */
6475 synchronize_sched();
6476
6477 trace_free_pid_list(pid_list);
6478}
6479
6480void ftrace_clear_pids(struct trace_array *tr)
6481{
6482 mutex_lock(&ftrace_lock);
6483
6484 clear_ftrace_pids(tr);
6485
6486 mutex_unlock(&ftrace_lock);
6487}
6488
6489static void ftrace_pid_reset(struct trace_array *tr)
6490{
6491 mutex_lock(&ftrace_lock);
6492 clear_ftrace_pids(tr);
6493
6494 ftrace_update_pid_func();
6495 ftrace_startup_all(0);
6496
6497 mutex_unlock(&ftrace_lock);
6498}
6499
6500/* Greater than any max PID */
6501#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6502
6503static void *fpid_start(struct seq_file *m, loff_t *pos)
6504 __acquires(RCU)
6505{
6506 struct trace_pid_list *pid_list;
6507 struct trace_array *tr = m->private;
6508
6509 mutex_lock(&ftrace_lock);
6510 rcu_read_lock_sched();
6511
6512 pid_list = rcu_dereference_sched(tr->function_pids);
6513
6514 if (!pid_list)
6515 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6516
6517 return trace_pid_start(pid_list, pos);
6518}
6519
6520static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6521{
6522 struct trace_array *tr = m->private;
6523 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6524
6525 if (v == FTRACE_NO_PIDS)
6526 return NULL;
6527
6528 return trace_pid_next(pid_list, v, pos);
6529}
6530
6531static void fpid_stop(struct seq_file *m, void *p)
6532 __releases(RCU)
6533{
6534 rcu_read_unlock_sched();
6535 mutex_unlock(&ftrace_lock);
6536}
6537
6538static int fpid_show(struct seq_file *m, void *v)
6539{
6540 if (v == FTRACE_NO_PIDS) {
6541 seq_puts(m, "no pid\n");
6542 return 0;
6543 }
6544
6545 return trace_pid_show(m, v);
6546}
6547
6548static const struct seq_operations ftrace_pid_sops = {
6549 .start = fpid_start,
6550 .next = fpid_next,
6551 .stop = fpid_stop,
6552 .show = fpid_show,
6553};
6554
6555static int
6556ftrace_pid_open(struct inode *inode, struct file *file)
6557{
6558 struct trace_array *tr = inode->i_private;
6559 struct seq_file *m;
6560 int ret = 0;
6561
6562 if (trace_array_get(tr) < 0)
6563 return -ENODEV;
6564
6565 if ((file->f_mode & FMODE_WRITE) &&
6566 (file->f_flags & O_TRUNC))
6567 ftrace_pid_reset(tr);
6568
6569 ret = seq_open(file, &ftrace_pid_sops);
6570 if (ret < 0) {
6571 trace_array_put(tr);
6572 } else {
6573 m = file->private_data;
6574 /* copy tr over to seq ops */
6575 m->private = tr;
6576 }
6577
6578 return ret;
6579}
6580
6581static void ignore_task_cpu(void *data)
6582{
6583 struct trace_array *tr = data;
6584 struct trace_pid_list *pid_list;
6585
6586 /*
6587 * This function is called by on_each_cpu() while the
6588 * event_mutex is held.
6589 */
6590 pid_list = rcu_dereference_protected(tr->function_pids,
6591 mutex_is_locked(&ftrace_lock));
6592
6593 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6594 trace_ignore_this_task(pid_list, current));
6595}
6596
6597static ssize_t
6598ftrace_pid_write(struct file *filp, const char __user *ubuf,
6599 size_t cnt, loff_t *ppos)
6600{
6601 struct seq_file *m = filp->private_data;
6602 struct trace_array *tr = m->private;
6603 struct trace_pid_list *filtered_pids = NULL;
6604 struct trace_pid_list *pid_list;
6605 ssize_t ret;
6606
6607 if (!cnt)
6608 return 0;
6609
6610 mutex_lock(&ftrace_lock);
6611
6612 filtered_pids = rcu_dereference_protected(tr->function_pids,
6613 lockdep_is_held(&ftrace_lock));
6614
6615 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6616 if (ret < 0)
6617 goto out;
6618
6619 rcu_assign_pointer(tr->function_pids, pid_list);
6620
6621 if (filtered_pids) {
6622 synchronize_sched();
6623 trace_free_pid_list(filtered_pids);
6624 } else if (pid_list) {
6625 /* Register a probe to set whether to ignore the tracing of a task */
6626 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6627 }
6628
6629 /*
6630 * Ignoring of pids is done at task switch. But we have to
6631 * check for those tasks that are currently running.
6632 * Always do this in case a pid was appended or removed.
6633 */
6634 on_each_cpu(ignore_task_cpu, tr, 1);
6635
6636 ftrace_update_pid_func();
6637 ftrace_startup_all(0);
6638 out:
6639 mutex_unlock(&ftrace_lock);
6640
6641 if (ret > 0)
6642 *ppos += ret;
6643
6644 return ret;
6645}
6646
6647static int
6648ftrace_pid_release(struct inode *inode, struct file *file)
6649{
6650 struct trace_array *tr = inode->i_private;
6651
6652 trace_array_put(tr);
6653
6654 return seq_release(inode, file);
6655}
6656
6657static const struct file_operations ftrace_pid_fops = {
6658 .open = ftrace_pid_open,
6659 .write = ftrace_pid_write,
6660 .read = seq_read,
6661 .llseek = tracing_lseek,
6662 .release = ftrace_pid_release,
6663};
6664
6665void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6666{
6667 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6668 tr, &ftrace_pid_fops);
6669}
6670
6671void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6672 struct dentry *d_tracer)
6673{
6674 /* Only the top level directory has the dyn_tracefs and profile */
6675 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6676
6677 ftrace_init_dyn_tracefs(d_tracer);
6678 ftrace_profile_tracefs(d_tracer);
6679}
6680
6681/**
6682 * ftrace_kill - kill ftrace
6683 *
6684 * This function should be used by panic code. It stops ftrace
6685 * but in a not so nice way. If you need to simply kill ftrace
6686 * from a non-atomic section, use ftrace_kill.
6687 */
6688void ftrace_kill(void)
6689{
6690 ftrace_disabled = 1;
6691 ftrace_enabled = 0;
6692 clear_ftrace_function();
6693}
6694
6695/**
6696 * Test if ftrace is dead or not.
6697 */
6698int ftrace_is_dead(void)
6699{
6700 return ftrace_disabled;
6701}
6702
6703/**
6704 * register_ftrace_function - register a function for profiling
6705 * @ops - ops structure that holds the function for profiling.
6706 *
6707 * Register a function to be called by all functions in the
6708 * kernel.
6709 *
6710 * Note: @ops->func and all the functions it calls must be labeled
6711 * with "notrace", otherwise it will go into a
6712 * recursive loop.
6713 */
6714int register_ftrace_function(struct ftrace_ops *ops)
6715{
6716 int ret = -1;
6717
6718 ftrace_ops_init(ops);
6719
6720 mutex_lock(&ftrace_lock);
6721
6722 ret = ftrace_startup(ops, 0);
6723
6724 mutex_unlock(&ftrace_lock);
6725
6726 return ret;
6727}
6728EXPORT_SYMBOL_GPL(register_ftrace_function);
6729
6730/**
6731 * unregister_ftrace_function - unregister a function for profiling.
6732 * @ops - ops structure that holds the function to unregister
6733 *
6734 * Unregister a function that was added to be called by ftrace profiling.
6735 */
6736int unregister_ftrace_function(struct ftrace_ops *ops)
6737{
6738 int ret;
6739
6740 mutex_lock(&ftrace_lock);
6741 ret = ftrace_shutdown(ops, 0);
6742 mutex_unlock(&ftrace_lock);
6743
6744 return ret;
6745}
6746EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6747
6748int
6749ftrace_enable_sysctl(struct ctl_table *table, int write,
6750 void __user *buffer, size_t *lenp,
6751 loff_t *ppos)
6752{
6753 int ret = -ENODEV;
6754
6755 mutex_lock(&ftrace_lock);
6756
6757 if (unlikely(ftrace_disabled))
6758 goto out;
6759
6760 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6761
6762 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6763 goto out;
6764
6765 last_ftrace_enabled = !!ftrace_enabled;
6766
6767 if (ftrace_enabled) {
6768
6769 /* we are starting ftrace again */
6770 if (rcu_dereference_protected(ftrace_ops_list,
6771 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6772 update_ftrace_function();
6773
6774 ftrace_startup_sysctl();
6775
6776 } else {
6777 /* stopping ftrace calls (just send to ftrace_stub) */
6778 ftrace_trace_function = ftrace_stub;
6779
6780 ftrace_shutdown_sysctl();
6781 }
6782
6783 out:
6784 mutex_unlock(&ftrace_lock);
6785 return ret;
6786}
6787
6788#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6789
6790static struct ftrace_ops graph_ops = {
6791 .func = ftrace_stub,
6792 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6793 FTRACE_OPS_FL_INITIALIZED |
6794 FTRACE_OPS_FL_PID |
6795 FTRACE_OPS_FL_STUB,
6796#ifdef FTRACE_GRAPH_TRAMP_ADDR
6797 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
6798 /* trampoline_size is only needed for dynamically allocated tramps */
6799#endif
6800 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
6801};
6802
6803void ftrace_graph_sleep_time_control(bool enable)
6804{
6805 fgraph_sleep_time = enable;
6806}
6807
6808void ftrace_graph_graph_time_control(bool enable)
6809{
6810 fgraph_graph_time = enable;
6811}
6812
6813int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
6814{
6815 return 0;
6816}
6817
6818/* The callbacks that hook a function */
6819trace_func_graph_ret_t ftrace_graph_return =
6820 (trace_func_graph_ret_t)ftrace_stub;
6821trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
6822static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
6823
6824/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
6825static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
6826{
6827 int i;
6828 int ret = 0;
6829 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
6830 struct task_struct *g, *t;
6831
6832 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
6833 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
6834 * sizeof(struct ftrace_ret_stack),
6835 GFP_KERNEL);
6836 if (!ret_stack_list[i]) {
6837 start = 0;
6838 end = i;
6839 ret = -ENOMEM;
6840 goto free;
6841 }
6842 }
6843
6844 read_lock(&tasklist_lock);
6845 do_each_thread(g, t) {
6846 if (start == end) {
6847 ret = -EAGAIN;
6848 goto unlock;
6849 }
6850
6851 if (t->ret_stack == NULL) {
6852 atomic_set(&t->tracing_graph_pause, 0);
6853 atomic_set(&t->trace_overrun, 0);
6854 t->curr_ret_stack = -1;
6855 /* Make sure the tasks see the -1 first: */
6856 smp_wmb();
6857 t->ret_stack = ret_stack_list[start++];
6858 }
6859 } while_each_thread(g, t);
6860
6861unlock:
6862 read_unlock(&tasklist_lock);
6863free:
6864 for (i = start; i < end; i++)
6865 kfree(ret_stack_list[i]);
6866 return ret;
6867}
6868
6869static void
6870ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
6871 struct task_struct *prev, struct task_struct *next)
6872{
6873 unsigned long long timestamp;
6874 int index;
6875
6876 /*
6877 * Does the user want to count the time a function was asleep.
6878 * If so, do not update the time stamps.
6879 */
6880 if (fgraph_sleep_time)
6881 return;
6882
6883 timestamp = trace_clock_local();
6884
6885 prev->ftrace_timestamp = timestamp;
6886
6887 /* only process tasks that we timestamped */
6888 if (!next->ftrace_timestamp)
6889 return;
6890
6891 /*
6892 * Update all the counters in next to make up for the
6893 * time next was sleeping.
6894 */
6895 timestamp -= next->ftrace_timestamp;
6896
6897 for (index = next->curr_ret_stack; index >= 0; index--)
6898 next->ret_stack[index].calltime += timestamp;
6899}
6900
6901/* Allocate a return stack for each task */
6902static int start_graph_tracing(void)
6903{
6904 struct ftrace_ret_stack **ret_stack_list;
6905 int ret, cpu;
6906
6907 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
6908 sizeof(struct ftrace_ret_stack *),
6909 GFP_KERNEL);
6910
6911 if (!ret_stack_list)
6912 return -ENOMEM;
6913
6914 /* The cpu_boot init_task->ret_stack will never be freed */
6915 for_each_online_cpu(cpu) {
6916 if (!idle_task(cpu)->ret_stack)
6917 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
6918 }
6919
6920 do {
6921 ret = alloc_retstack_tasklist(ret_stack_list);
6922 } while (ret == -EAGAIN);
6923
6924 if (!ret) {
6925 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6926 if (ret)
6927 pr_info("ftrace_graph: Couldn't activate tracepoint"
6928 " probe to kernel_sched_switch\n");
6929 }
6930
6931 kfree(ret_stack_list);
6932 return ret;
6933}
6934
6935/*
6936 * Hibernation protection.
6937 * The state of the current task is too much unstable during
6938 * suspend/restore to disk. We want to protect against that.
6939 */
6940static int
6941ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
6942 void *unused)
6943{
6944 switch (state) {
6945 case PM_HIBERNATION_PREPARE:
6946 pause_graph_tracing();
6947 break;
6948
6949 case PM_POST_HIBERNATION:
6950 unpause_graph_tracing();
6951 break;
6952 }
6953 return NOTIFY_DONE;
6954}
6955
6956static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
6957{
6958 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
6959 return 0;
6960 return __ftrace_graph_entry(trace);
6961}
6962
6963/*
6964 * The function graph tracer should only trace the functions defined
6965 * by set_ftrace_filter and set_ftrace_notrace. If another function
6966 * tracer ops is registered, the graph tracer requires testing the
6967 * function against the global ops, and not just trace any function
6968 * that any ftrace_ops registered.
6969 */
6970static void update_function_graph_func(void)
6971{
6972 struct ftrace_ops *op;
6973 bool do_test = false;
6974
6975 /*
6976 * The graph and global ops share the same set of functions
6977 * to test. If any other ops is on the list, then
6978 * the graph tracing needs to test if its the function
6979 * it should call.
6980 */
6981 do_for_each_ftrace_op(op, ftrace_ops_list) {
6982 if (op != &global_ops && op != &graph_ops &&
6983 op != &ftrace_list_end) {
6984 do_test = true;
6985 /* in double loop, break out with goto */
6986 goto out;
6987 }
6988 } while_for_each_ftrace_op(op);
6989 out:
6990 if (do_test)
6991 ftrace_graph_entry = ftrace_graph_entry_test;
6992 else
6993 ftrace_graph_entry = __ftrace_graph_entry;
6994}
6995
6996static struct notifier_block ftrace_suspend_notifier = {
6997 .notifier_call = ftrace_suspend_notifier_call,
6998};
6999
7000int register_ftrace_graph(trace_func_graph_ret_t retfunc,
7001 trace_func_graph_ent_t entryfunc)
7002{
7003 int ret = 0;
7004
7005 mutex_lock(&ftrace_lock);
7006
7007 /* we currently allow only one tracer registered at a time */
7008 if (ftrace_graph_active) {
7009 ret = -EBUSY;
7010 goto out;
7011 }
7012
7013 register_pm_notifier(&ftrace_suspend_notifier);
7014
7015 ftrace_graph_active++;
7016 ret = start_graph_tracing();
7017 if (ret) {
7018 ftrace_graph_active--;
7019 goto out;
7020 }
7021
7022 ftrace_graph_return = retfunc;
7023
7024 /*
7025 * Update the indirect function to the entryfunc, and the
7026 * function that gets called to the entry_test first. Then
7027 * call the update fgraph entry function to determine if
7028 * the entryfunc should be called directly or not.
7029 */
7030 __ftrace_graph_entry = entryfunc;
7031 ftrace_graph_entry = ftrace_graph_entry_test;
7032 update_function_graph_func();
7033
7034 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
7035out:
7036 mutex_unlock(&ftrace_lock);
7037 return ret;
7038}
7039
7040void unregister_ftrace_graph(void)
7041{
7042 mutex_lock(&ftrace_lock);
7043
7044 if (unlikely(!ftrace_graph_active))
7045 goto out;
7046
7047 ftrace_graph_active--;
7048 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
7049 ftrace_graph_entry = ftrace_graph_entry_stub;
7050 __ftrace_graph_entry = ftrace_graph_entry_stub;
7051 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
7052 unregister_pm_notifier(&ftrace_suspend_notifier);
7053 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
7054
7055 out:
7056 mutex_unlock(&ftrace_lock);
7057}
7058
7059static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
7060
7061static void
7062graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
7063{
7064 atomic_set(&t->tracing_graph_pause, 0);
7065 atomic_set(&t->trace_overrun, 0);
7066 t->ftrace_timestamp = 0;
7067 /* make curr_ret_stack visible before we add the ret_stack */
7068 smp_wmb();
7069 t->ret_stack = ret_stack;
7070}
7071
7072/*
7073 * Allocate a return stack for the idle task. May be the first
7074 * time through, or it may be done by CPU hotplug online.
7075 */
7076void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
7077{
7078 t->curr_ret_stack = -1;
7079 /*
7080 * The idle task has no parent, it either has its own
7081 * stack or no stack at all.
7082 */
7083 if (t->ret_stack)
7084 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
7085
7086 if (ftrace_graph_active) {
7087 struct ftrace_ret_stack *ret_stack;
7088
7089 ret_stack = per_cpu(idle_ret_stack, cpu);
7090 if (!ret_stack) {
7091 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
7092 * sizeof(struct ftrace_ret_stack),
7093 GFP_KERNEL);
7094 if (!ret_stack)
7095 return;
7096 per_cpu(idle_ret_stack, cpu) = ret_stack;
7097 }
7098 graph_init_task(t, ret_stack);
7099 }
7100}
7101
7102/* Allocate a return stack for newly created task */
7103void ftrace_graph_init_task(struct task_struct *t)
7104{
7105 /* Make sure we do not use the parent ret_stack */
7106 t->ret_stack = NULL;
7107 t->curr_ret_stack = -1;
7108
7109 if (ftrace_graph_active) {
7110 struct ftrace_ret_stack *ret_stack;
7111
7112 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
7113 * sizeof(struct ftrace_ret_stack),
7114 GFP_KERNEL);
7115 if (!ret_stack)
7116 return;
7117 graph_init_task(t, ret_stack);
7118 }
7119}
7120
7121void ftrace_graph_exit_task(struct task_struct *t)
7122{
7123 struct ftrace_ret_stack *ret_stack = t->ret_stack;
7124
7125 t->ret_stack = NULL;
7126 /* NULL must become visible to IRQs before we free it: */
7127 barrier();
7128
7129 kfree(ret_stack);
7130}
7131#endif
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code in the latency_tracer, that is:
12 *
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
15 */
16
17#include <linux/stop_machine.h>
18#include <linux/clocksource.h>
19#include <linux/sched/task.h>
20#include <linux/kallsyms.h>
21#include <linux/security.h>
22#include <linux/seq_file.h>
23#include <linux/tracefs.h>
24#include <linux/hardirq.h>
25#include <linux/kthread.h>
26#include <linux/uaccess.h>
27#include <linux/bsearch.h>
28#include <linux/module.h>
29#include <linux/ftrace.h>
30#include <linux/sysctl.h>
31#include <linux/slab.h>
32#include <linux/ctype.h>
33#include <linux/sort.h>
34#include <linux/list.h>
35#include <linux/hash.h>
36#include <linux/rcupdate.h>
37#include <linux/kprobes.h>
38
39#include <trace/events/sched.h>
40
41#include <asm/sections.h>
42#include <asm/setup.h>
43
44#include "ftrace_internal.h"
45#include "trace_output.h"
46#include "trace_stat.h"
47
48#define FTRACE_WARN_ON(cond) \
49 ({ \
50 int ___r = cond; \
51 if (WARN_ON(___r)) \
52 ftrace_kill(); \
53 ___r; \
54 })
55
56#define FTRACE_WARN_ON_ONCE(cond) \
57 ({ \
58 int ___r = cond; \
59 if (WARN_ON_ONCE(___r)) \
60 ftrace_kill(); \
61 ___r; \
62 })
63
64/* hash bits for specific function selection */
65#define FTRACE_HASH_DEFAULT_BITS 10
66#define FTRACE_HASH_MAX_BITS 12
67
68#ifdef CONFIG_DYNAMIC_FTRACE
69#define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
72#else
73#define INIT_OPS_HASH(opsname)
74#endif
75
76enum {
77 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
79};
80
81struct ftrace_ops ftrace_list_end __read_mostly = {
82 .func = ftrace_stub,
83 .flags = FTRACE_OPS_FL_STUB,
84 INIT_OPS_HASH(ftrace_list_end)
85};
86
87/* ftrace_enabled is a method to turn ftrace on or off */
88int ftrace_enabled __read_mostly;
89static int last_ftrace_enabled;
90
91/* Current function tracing op */
92struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
93/* What to set function_trace_op to */
94static struct ftrace_ops *set_function_trace_op;
95
96static bool ftrace_pids_enabled(struct ftrace_ops *ops)
97{
98 struct trace_array *tr;
99
100 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
101 return false;
102
103 tr = ops->private;
104
105 return tr->function_pids != NULL || tr->function_no_pids != NULL;
106}
107
108static void ftrace_update_trampoline(struct ftrace_ops *ops);
109
110/*
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
113 */
114static int ftrace_disabled __read_mostly;
115
116DEFINE_MUTEX(ftrace_lock);
117
118struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
119ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
120struct ftrace_ops global_ops;
121
122#if ARCH_SUPPORTS_FTRACE_OPS
123static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
124 struct ftrace_ops *op, struct ftrace_regs *fregs);
125#else
126/* See comment below, where ftrace_ops_list_func is defined */
127static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
128#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
129#endif
130
131static inline void ftrace_ops_init(struct ftrace_ops *ops)
132{
133#ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
135 mutex_init(&ops->local_hash.regex_lock);
136 ops->func_hash = &ops->local_hash;
137 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
138 }
139#endif
140}
141
142static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
143 struct ftrace_ops *op, struct ftrace_regs *fregs)
144{
145 struct trace_array *tr = op->private;
146 int pid;
147
148 if (tr) {
149 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
150 if (pid == FTRACE_PID_IGNORE)
151 return;
152 if (pid != FTRACE_PID_TRACE &&
153 pid != current->pid)
154 return;
155 }
156
157 op->saved_func(ip, parent_ip, op, fregs);
158}
159
160static void ftrace_sync_ipi(void *data)
161{
162 /* Probably not needed, but do it anyway */
163 smp_rmb();
164}
165
166static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
167{
168 /*
169 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
170 * then it needs to call the list anyway.
171 */
172 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
173 FTRACE_FORCE_LIST_FUNC)
174 return ftrace_ops_list_func;
175
176 return ftrace_ops_get_func(ops);
177}
178
179static void update_ftrace_function(void)
180{
181 ftrace_func_t func;
182
183 /*
184 * Prepare the ftrace_ops that the arch callback will use.
185 * If there's only one ftrace_ops registered, the ftrace_ops_list
186 * will point to the ops we want.
187 */
188 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
189 lockdep_is_held(&ftrace_lock));
190
191 /* If there's no ftrace_ops registered, just call the stub function */
192 if (set_function_trace_op == &ftrace_list_end) {
193 func = ftrace_stub;
194
195 /*
196 * If we are at the end of the list and this ops is
197 * recursion safe and not dynamic and the arch supports passing ops,
198 * then have the mcount trampoline call the function directly.
199 */
200 } else if (rcu_dereference_protected(ftrace_ops_list->next,
201 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
202 func = ftrace_ops_get_list_func(ftrace_ops_list);
203
204 } else {
205 /* Just use the default ftrace_ops */
206 set_function_trace_op = &ftrace_list_end;
207 func = ftrace_ops_list_func;
208 }
209
210 update_function_graph_func();
211
212 /* If there's no change, then do nothing more here */
213 if (ftrace_trace_function == func)
214 return;
215
216 /*
217 * If we are using the list function, it doesn't care
218 * about the function_trace_ops.
219 */
220 if (func == ftrace_ops_list_func) {
221 ftrace_trace_function = func;
222 /*
223 * Don't even bother setting function_trace_ops,
224 * it would be racy to do so anyway.
225 */
226 return;
227 }
228
229#ifndef CONFIG_DYNAMIC_FTRACE
230 /*
231 * For static tracing, we need to be a bit more careful.
232 * The function change takes affect immediately. Thus,
233 * we need to coordinate the setting of the function_trace_ops
234 * with the setting of the ftrace_trace_function.
235 *
236 * Set the function to the list ops, which will call the
237 * function we want, albeit indirectly, but it handles the
238 * ftrace_ops and doesn't depend on function_trace_op.
239 */
240 ftrace_trace_function = ftrace_ops_list_func;
241 /*
242 * Make sure all CPUs see this. Yes this is slow, but static
243 * tracing is slow and nasty to have enabled.
244 */
245 synchronize_rcu_tasks_rude();
246 /* Now all cpus are using the list ops. */
247 function_trace_op = set_function_trace_op;
248 /* Make sure the function_trace_op is visible on all CPUs */
249 smp_wmb();
250 /* Nasty way to force a rmb on all cpus */
251 smp_call_function(ftrace_sync_ipi, NULL, 1);
252 /* OK, we are all set to update the ftrace_trace_function now! */
253#endif /* !CONFIG_DYNAMIC_FTRACE */
254
255 ftrace_trace_function = func;
256}
257
258static void add_ftrace_ops(struct ftrace_ops __rcu **list,
259 struct ftrace_ops *ops)
260{
261 rcu_assign_pointer(ops->next, *list);
262
263 /*
264 * We are entering ops into the list but another
265 * CPU might be walking that list. We need to make sure
266 * the ops->next pointer is valid before another CPU sees
267 * the ops pointer included into the list.
268 */
269 rcu_assign_pointer(*list, ops);
270}
271
272static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
273 struct ftrace_ops *ops)
274{
275 struct ftrace_ops **p;
276
277 /*
278 * If we are removing the last function, then simply point
279 * to the ftrace_stub.
280 */
281 if (rcu_dereference_protected(*list,
282 lockdep_is_held(&ftrace_lock)) == ops &&
283 rcu_dereference_protected(ops->next,
284 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
285 *list = &ftrace_list_end;
286 return 0;
287 }
288
289 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
290 if (*p == ops)
291 break;
292
293 if (*p != ops)
294 return -1;
295
296 *p = (*p)->next;
297 return 0;
298}
299
300static void ftrace_update_trampoline(struct ftrace_ops *ops);
301
302int __register_ftrace_function(struct ftrace_ops *ops)
303{
304 if (ops->flags & FTRACE_OPS_FL_DELETED)
305 return -EINVAL;
306
307 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
308 return -EBUSY;
309
310#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
311 /*
312 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
313 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
314 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
315 */
316 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
317 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
318 return -EINVAL;
319
320 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
321 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
322#endif
323 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
324 return -EBUSY;
325
326 if (!core_kernel_data((unsigned long)ops))
327 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
328
329 add_ftrace_ops(&ftrace_ops_list, ops);
330
331 /* Always save the function, and reset at unregistering */
332 ops->saved_func = ops->func;
333
334 if (ftrace_pids_enabled(ops))
335 ops->func = ftrace_pid_func;
336
337 ftrace_update_trampoline(ops);
338
339 if (ftrace_enabled)
340 update_ftrace_function();
341
342 return 0;
343}
344
345int __unregister_ftrace_function(struct ftrace_ops *ops)
346{
347 int ret;
348
349 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
350 return -EBUSY;
351
352 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
353
354 if (ret < 0)
355 return ret;
356
357 if (ftrace_enabled)
358 update_ftrace_function();
359
360 ops->func = ops->saved_func;
361
362 return 0;
363}
364
365static void ftrace_update_pid_func(void)
366{
367 struct ftrace_ops *op;
368
369 /* Only do something if we are tracing something */
370 if (ftrace_trace_function == ftrace_stub)
371 return;
372
373 do_for_each_ftrace_op(op, ftrace_ops_list) {
374 if (op->flags & FTRACE_OPS_FL_PID) {
375 op->func = ftrace_pids_enabled(op) ?
376 ftrace_pid_func : op->saved_func;
377 ftrace_update_trampoline(op);
378 }
379 } while_for_each_ftrace_op(op);
380
381 update_ftrace_function();
382}
383
384#ifdef CONFIG_FUNCTION_PROFILER
385struct ftrace_profile {
386 struct hlist_node node;
387 unsigned long ip;
388 unsigned long counter;
389#ifdef CONFIG_FUNCTION_GRAPH_TRACER
390 unsigned long long time;
391 unsigned long long time_squared;
392#endif
393};
394
395struct ftrace_profile_page {
396 struct ftrace_profile_page *next;
397 unsigned long index;
398 struct ftrace_profile records[];
399};
400
401struct ftrace_profile_stat {
402 atomic_t disabled;
403 struct hlist_head *hash;
404 struct ftrace_profile_page *pages;
405 struct ftrace_profile_page *start;
406 struct tracer_stat stat;
407};
408
409#define PROFILE_RECORDS_SIZE \
410 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
411
412#define PROFILES_PER_PAGE \
413 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
414
415static int ftrace_profile_enabled __read_mostly;
416
417/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
418static DEFINE_MUTEX(ftrace_profile_lock);
419
420static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
421
422#define FTRACE_PROFILE_HASH_BITS 10
423#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
424
425static void *
426function_stat_next(void *v, int idx)
427{
428 struct ftrace_profile *rec = v;
429 struct ftrace_profile_page *pg;
430
431 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
432
433 again:
434 if (idx != 0)
435 rec++;
436
437 if ((void *)rec >= (void *)&pg->records[pg->index]) {
438 pg = pg->next;
439 if (!pg)
440 return NULL;
441 rec = &pg->records[0];
442 if (!rec->counter)
443 goto again;
444 }
445
446 return rec;
447}
448
449static void *function_stat_start(struct tracer_stat *trace)
450{
451 struct ftrace_profile_stat *stat =
452 container_of(trace, struct ftrace_profile_stat, stat);
453
454 if (!stat || !stat->start)
455 return NULL;
456
457 return function_stat_next(&stat->start->records[0], 0);
458}
459
460#ifdef CONFIG_FUNCTION_GRAPH_TRACER
461/* function graph compares on total time */
462static int function_stat_cmp(const void *p1, const void *p2)
463{
464 const struct ftrace_profile *a = p1;
465 const struct ftrace_profile *b = p2;
466
467 if (a->time < b->time)
468 return -1;
469 if (a->time > b->time)
470 return 1;
471 else
472 return 0;
473}
474#else
475/* not function graph compares against hits */
476static int function_stat_cmp(const void *p1, const void *p2)
477{
478 const struct ftrace_profile *a = p1;
479 const struct ftrace_profile *b = p2;
480
481 if (a->counter < b->counter)
482 return -1;
483 if (a->counter > b->counter)
484 return 1;
485 else
486 return 0;
487}
488#endif
489
490static int function_stat_headers(struct seq_file *m)
491{
492#ifdef CONFIG_FUNCTION_GRAPH_TRACER
493 seq_puts(m, " Function "
494 "Hit Time Avg s^2\n"
495 " -------- "
496 "--- ---- --- ---\n");
497#else
498 seq_puts(m, " Function Hit\n"
499 " -------- ---\n");
500#endif
501 return 0;
502}
503
504static int function_stat_show(struct seq_file *m, void *v)
505{
506 struct ftrace_profile *rec = v;
507 char str[KSYM_SYMBOL_LEN];
508 int ret = 0;
509#ifdef CONFIG_FUNCTION_GRAPH_TRACER
510 static struct trace_seq s;
511 unsigned long long avg;
512 unsigned long long stddev;
513#endif
514 mutex_lock(&ftrace_profile_lock);
515
516 /* we raced with function_profile_reset() */
517 if (unlikely(rec->counter == 0)) {
518 ret = -EBUSY;
519 goto out;
520 }
521
522#ifdef CONFIG_FUNCTION_GRAPH_TRACER
523 avg = div64_ul(rec->time, rec->counter);
524 if (tracing_thresh && (avg < tracing_thresh))
525 goto out;
526#endif
527
528 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
529 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
530
531#ifdef CONFIG_FUNCTION_GRAPH_TRACER
532 seq_puts(m, " ");
533
534 /* Sample standard deviation (s^2) */
535 if (rec->counter <= 1)
536 stddev = 0;
537 else {
538 /*
539 * Apply Welford's method:
540 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
541 */
542 stddev = rec->counter * rec->time_squared -
543 rec->time * rec->time;
544
545 /*
546 * Divide only 1000 for ns^2 -> us^2 conversion.
547 * trace_print_graph_duration will divide 1000 again.
548 */
549 stddev = div64_ul(stddev,
550 rec->counter * (rec->counter - 1) * 1000);
551 }
552
553 trace_seq_init(&s);
554 trace_print_graph_duration(rec->time, &s);
555 trace_seq_puts(&s, " ");
556 trace_print_graph_duration(avg, &s);
557 trace_seq_puts(&s, " ");
558 trace_print_graph_duration(stddev, &s);
559 trace_print_seq(m, &s);
560#endif
561 seq_putc(m, '\n');
562out:
563 mutex_unlock(&ftrace_profile_lock);
564
565 return ret;
566}
567
568static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
569{
570 struct ftrace_profile_page *pg;
571
572 pg = stat->pages = stat->start;
573
574 while (pg) {
575 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
576 pg->index = 0;
577 pg = pg->next;
578 }
579
580 memset(stat->hash, 0,
581 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
582}
583
584int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
585{
586 struct ftrace_profile_page *pg;
587 int functions;
588 int pages;
589 int i;
590
591 /* If we already allocated, do nothing */
592 if (stat->pages)
593 return 0;
594
595 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
596 if (!stat->pages)
597 return -ENOMEM;
598
599#ifdef CONFIG_DYNAMIC_FTRACE
600 functions = ftrace_update_tot_cnt;
601#else
602 /*
603 * We do not know the number of functions that exist because
604 * dynamic tracing is what counts them. With past experience
605 * we have around 20K functions. That should be more than enough.
606 * It is highly unlikely we will execute every function in
607 * the kernel.
608 */
609 functions = 20000;
610#endif
611
612 pg = stat->start = stat->pages;
613
614 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
615
616 for (i = 1; i < pages; i++) {
617 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
618 if (!pg->next)
619 goto out_free;
620 pg = pg->next;
621 }
622
623 return 0;
624
625 out_free:
626 pg = stat->start;
627 while (pg) {
628 unsigned long tmp = (unsigned long)pg;
629
630 pg = pg->next;
631 free_page(tmp);
632 }
633
634 stat->pages = NULL;
635 stat->start = NULL;
636
637 return -ENOMEM;
638}
639
640static int ftrace_profile_init_cpu(int cpu)
641{
642 struct ftrace_profile_stat *stat;
643 int size;
644
645 stat = &per_cpu(ftrace_profile_stats, cpu);
646
647 if (stat->hash) {
648 /* If the profile is already created, simply reset it */
649 ftrace_profile_reset(stat);
650 return 0;
651 }
652
653 /*
654 * We are profiling all functions, but usually only a few thousand
655 * functions are hit. We'll make a hash of 1024 items.
656 */
657 size = FTRACE_PROFILE_HASH_SIZE;
658
659 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
660
661 if (!stat->hash)
662 return -ENOMEM;
663
664 /* Preallocate the function profiling pages */
665 if (ftrace_profile_pages_init(stat) < 0) {
666 kfree(stat->hash);
667 stat->hash = NULL;
668 return -ENOMEM;
669 }
670
671 return 0;
672}
673
674static int ftrace_profile_init(void)
675{
676 int cpu;
677 int ret = 0;
678
679 for_each_possible_cpu(cpu) {
680 ret = ftrace_profile_init_cpu(cpu);
681 if (ret)
682 break;
683 }
684
685 return ret;
686}
687
688/* interrupts must be disabled */
689static struct ftrace_profile *
690ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
691{
692 struct ftrace_profile *rec;
693 struct hlist_head *hhd;
694 unsigned long key;
695
696 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
697 hhd = &stat->hash[key];
698
699 if (hlist_empty(hhd))
700 return NULL;
701
702 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
703 if (rec->ip == ip)
704 return rec;
705 }
706
707 return NULL;
708}
709
710static void ftrace_add_profile(struct ftrace_profile_stat *stat,
711 struct ftrace_profile *rec)
712{
713 unsigned long key;
714
715 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
716 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
717}
718
719/*
720 * The memory is already allocated, this simply finds a new record to use.
721 */
722static struct ftrace_profile *
723ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
724{
725 struct ftrace_profile *rec = NULL;
726
727 /* prevent recursion (from NMIs) */
728 if (atomic_inc_return(&stat->disabled) != 1)
729 goto out;
730
731 /*
732 * Try to find the function again since an NMI
733 * could have added it
734 */
735 rec = ftrace_find_profiled_func(stat, ip);
736 if (rec)
737 goto out;
738
739 if (stat->pages->index == PROFILES_PER_PAGE) {
740 if (!stat->pages->next)
741 goto out;
742 stat->pages = stat->pages->next;
743 }
744
745 rec = &stat->pages->records[stat->pages->index++];
746 rec->ip = ip;
747 ftrace_add_profile(stat, rec);
748
749 out:
750 atomic_dec(&stat->disabled);
751
752 return rec;
753}
754
755static void
756function_profile_call(unsigned long ip, unsigned long parent_ip,
757 struct ftrace_ops *ops, struct ftrace_regs *fregs)
758{
759 struct ftrace_profile_stat *stat;
760 struct ftrace_profile *rec;
761 unsigned long flags;
762
763 if (!ftrace_profile_enabled)
764 return;
765
766 local_irq_save(flags);
767
768 stat = this_cpu_ptr(&ftrace_profile_stats);
769 if (!stat->hash || !ftrace_profile_enabled)
770 goto out;
771
772 rec = ftrace_find_profiled_func(stat, ip);
773 if (!rec) {
774 rec = ftrace_profile_alloc(stat, ip);
775 if (!rec)
776 goto out;
777 }
778
779 rec->counter++;
780 out:
781 local_irq_restore(flags);
782}
783
784#ifdef CONFIG_FUNCTION_GRAPH_TRACER
785static bool fgraph_graph_time = true;
786
787void ftrace_graph_graph_time_control(bool enable)
788{
789 fgraph_graph_time = enable;
790}
791
792static int profile_graph_entry(struct ftrace_graph_ent *trace)
793{
794 struct ftrace_ret_stack *ret_stack;
795
796 function_profile_call(trace->func, 0, NULL, NULL);
797
798 /* If function graph is shutting down, ret_stack can be NULL */
799 if (!current->ret_stack)
800 return 0;
801
802 ret_stack = ftrace_graph_get_ret_stack(current, 0);
803 if (ret_stack)
804 ret_stack->subtime = 0;
805
806 return 1;
807}
808
809static void profile_graph_return(struct ftrace_graph_ret *trace)
810{
811 struct ftrace_ret_stack *ret_stack;
812 struct ftrace_profile_stat *stat;
813 unsigned long long calltime;
814 struct ftrace_profile *rec;
815 unsigned long flags;
816
817 local_irq_save(flags);
818 stat = this_cpu_ptr(&ftrace_profile_stats);
819 if (!stat->hash || !ftrace_profile_enabled)
820 goto out;
821
822 /* If the calltime was zero'd ignore it */
823 if (!trace->calltime)
824 goto out;
825
826 calltime = trace->rettime - trace->calltime;
827
828 if (!fgraph_graph_time) {
829
830 /* Append this call time to the parent time to subtract */
831 ret_stack = ftrace_graph_get_ret_stack(current, 1);
832 if (ret_stack)
833 ret_stack->subtime += calltime;
834
835 ret_stack = ftrace_graph_get_ret_stack(current, 0);
836 if (ret_stack && ret_stack->subtime < calltime)
837 calltime -= ret_stack->subtime;
838 else
839 calltime = 0;
840 }
841
842 rec = ftrace_find_profiled_func(stat, trace->func);
843 if (rec) {
844 rec->time += calltime;
845 rec->time_squared += calltime * calltime;
846 }
847
848 out:
849 local_irq_restore(flags);
850}
851
852static struct fgraph_ops fprofiler_ops = {
853 .entryfunc = &profile_graph_entry,
854 .retfunc = &profile_graph_return,
855};
856
857static int register_ftrace_profiler(void)
858{
859 return register_ftrace_graph(&fprofiler_ops);
860}
861
862static void unregister_ftrace_profiler(void)
863{
864 unregister_ftrace_graph(&fprofiler_ops);
865}
866#else
867static struct ftrace_ops ftrace_profile_ops __read_mostly = {
868 .func = function_profile_call,
869 .flags = FTRACE_OPS_FL_INITIALIZED,
870 INIT_OPS_HASH(ftrace_profile_ops)
871};
872
873static int register_ftrace_profiler(void)
874{
875 return register_ftrace_function(&ftrace_profile_ops);
876}
877
878static void unregister_ftrace_profiler(void)
879{
880 unregister_ftrace_function(&ftrace_profile_ops);
881}
882#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
883
884static ssize_t
885ftrace_profile_write(struct file *filp, const char __user *ubuf,
886 size_t cnt, loff_t *ppos)
887{
888 unsigned long val;
889 int ret;
890
891 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
892 if (ret)
893 return ret;
894
895 val = !!val;
896
897 mutex_lock(&ftrace_profile_lock);
898 if (ftrace_profile_enabled ^ val) {
899 if (val) {
900 ret = ftrace_profile_init();
901 if (ret < 0) {
902 cnt = ret;
903 goto out;
904 }
905
906 ret = register_ftrace_profiler();
907 if (ret < 0) {
908 cnt = ret;
909 goto out;
910 }
911 ftrace_profile_enabled = 1;
912 } else {
913 ftrace_profile_enabled = 0;
914 /*
915 * unregister_ftrace_profiler calls stop_machine
916 * so this acts like an synchronize_rcu.
917 */
918 unregister_ftrace_profiler();
919 }
920 }
921 out:
922 mutex_unlock(&ftrace_profile_lock);
923
924 *ppos += cnt;
925
926 return cnt;
927}
928
929static ssize_t
930ftrace_profile_read(struct file *filp, char __user *ubuf,
931 size_t cnt, loff_t *ppos)
932{
933 char buf[64]; /* big enough to hold a number */
934 int r;
935
936 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
937 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
938}
939
940static const struct file_operations ftrace_profile_fops = {
941 .open = tracing_open_generic,
942 .read = ftrace_profile_read,
943 .write = ftrace_profile_write,
944 .llseek = default_llseek,
945};
946
947/* used to initialize the real stat files */
948static struct tracer_stat function_stats __initdata = {
949 .name = "functions",
950 .stat_start = function_stat_start,
951 .stat_next = function_stat_next,
952 .stat_cmp = function_stat_cmp,
953 .stat_headers = function_stat_headers,
954 .stat_show = function_stat_show
955};
956
957static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
958{
959 struct ftrace_profile_stat *stat;
960 struct dentry *entry;
961 char *name;
962 int ret;
963 int cpu;
964
965 for_each_possible_cpu(cpu) {
966 stat = &per_cpu(ftrace_profile_stats, cpu);
967
968 name = kasprintf(GFP_KERNEL, "function%d", cpu);
969 if (!name) {
970 /*
971 * The files created are permanent, if something happens
972 * we still do not free memory.
973 */
974 WARN(1,
975 "Could not allocate stat file for cpu %d\n",
976 cpu);
977 return;
978 }
979 stat->stat = function_stats;
980 stat->stat.name = name;
981 ret = register_stat_tracer(&stat->stat);
982 if (ret) {
983 WARN(1,
984 "Could not register function stat for cpu %d\n",
985 cpu);
986 kfree(name);
987 return;
988 }
989 }
990
991 entry = tracefs_create_file("function_profile_enabled", 0644,
992 d_tracer, NULL, &ftrace_profile_fops);
993 if (!entry)
994 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
995}
996
997#else /* CONFIG_FUNCTION_PROFILER */
998static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
999{
1000}
1001#endif /* CONFIG_FUNCTION_PROFILER */
1002
1003#ifdef CONFIG_DYNAMIC_FTRACE
1004
1005static struct ftrace_ops *removed_ops;
1006
1007/*
1008 * Set when doing a global update, like enabling all recs or disabling them.
1009 * It is not set when just updating a single ftrace_ops.
1010 */
1011static bool update_all_ops;
1012
1013#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1014# error Dynamic ftrace depends on MCOUNT_RECORD
1015#endif
1016
1017struct ftrace_func_probe {
1018 struct ftrace_probe_ops *probe_ops;
1019 struct ftrace_ops ops;
1020 struct trace_array *tr;
1021 struct list_head list;
1022 void *data;
1023 int ref;
1024};
1025
1026/*
1027 * We make these constant because no one should touch them,
1028 * but they are used as the default "empty hash", to avoid allocating
1029 * it all the time. These are in a read only section such that if
1030 * anyone does try to modify it, it will cause an exception.
1031 */
1032static const struct hlist_head empty_buckets[1];
1033static const struct ftrace_hash empty_hash = {
1034 .buckets = (struct hlist_head *)empty_buckets,
1035};
1036#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1037
1038struct ftrace_ops global_ops = {
1039 .func = ftrace_stub,
1040 .local_hash.notrace_hash = EMPTY_HASH,
1041 .local_hash.filter_hash = EMPTY_HASH,
1042 INIT_OPS_HASH(global_ops)
1043 .flags = FTRACE_OPS_FL_INITIALIZED |
1044 FTRACE_OPS_FL_PID,
1045};
1046
1047/*
1048 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1049 */
1050struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1051{
1052 struct ftrace_ops *op = NULL;
1053
1054 /*
1055 * Some of the ops may be dynamically allocated,
1056 * they are freed after a synchronize_rcu().
1057 */
1058 preempt_disable_notrace();
1059
1060 do_for_each_ftrace_op(op, ftrace_ops_list) {
1061 /*
1062 * This is to check for dynamically allocated trampolines.
1063 * Trampolines that are in kernel text will have
1064 * core_kernel_text() return true.
1065 */
1066 if (op->trampoline && op->trampoline_size)
1067 if (addr >= op->trampoline &&
1068 addr < op->trampoline + op->trampoline_size) {
1069 preempt_enable_notrace();
1070 return op;
1071 }
1072 } while_for_each_ftrace_op(op);
1073 preempt_enable_notrace();
1074
1075 return NULL;
1076}
1077
1078/*
1079 * This is used by __kernel_text_address() to return true if the
1080 * address is on a dynamically allocated trampoline that would
1081 * not return true for either core_kernel_text() or
1082 * is_module_text_address().
1083 */
1084bool is_ftrace_trampoline(unsigned long addr)
1085{
1086 return ftrace_ops_trampoline(addr) != NULL;
1087}
1088
1089struct ftrace_page {
1090 struct ftrace_page *next;
1091 struct dyn_ftrace *records;
1092 int index;
1093 int order;
1094};
1095
1096#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1097#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1098
1099static struct ftrace_page *ftrace_pages_start;
1100static struct ftrace_page *ftrace_pages;
1101
1102static __always_inline unsigned long
1103ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1104{
1105 if (hash->size_bits > 0)
1106 return hash_long(ip, hash->size_bits);
1107
1108 return 0;
1109}
1110
1111/* Only use this function if ftrace_hash_empty() has already been tested */
1112static __always_inline struct ftrace_func_entry *
1113__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1114{
1115 unsigned long key;
1116 struct ftrace_func_entry *entry;
1117 struct hlist_head *hhd;
1118
1119 key = ftrace_hash_key(hash, ip);
1120 hhd = &hash->buckets[key];
1121
1122 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1123 if (entry->ip == ip)
1124 return entry;
1125 }
1126 return NULL;
1127}
1128
1129/**
1130 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1131 * @hash: The hash to look at
1132 * @ip: The instruction pointer to test
1133 *
1134 * Search a given @hash to see if a given instruction pointer (@ip)
1135 * exists in it.
1136 *
1137 * Returns the entry that holds the @ip if found. NULL otherwise.
1138 */
1139struct ftrace_func_entry *
1140ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1141{
1142 if (ftrace_hash_empty(hash))
1143 return NULL;
1144
1145 return __ftrace_lookup_ip(hash, ip);
1146}
1147
1148static void __add_hash_entry(struct ftrace_hash *hash,
1149 struct ftrace_func_entry *entry)
1150{
1151 struct hlist_head *hhd;
1152 unsigned long key;
1153
1154 key = ftrace_hash_key(hash, entry->ip);
1155 hhd = &hash->buckets[key];
1156 hlist_add_head(&entry->hlist, hhd);
1157 hash->count++;
1158}
1159
1160static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1161{
1162 struct ftrace_func_entry *entry;
1163
1164 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1165 if (!entry)
1166 return -ENOMEM;
1167
1168 entry->ip = ip;
1169 __add_hash_entry(hash, entry);
1170
1171 return 0;
1172}
1173
1174static void
1175free_hash_entry(struct ftrace_hash *hash,
1176 struct ftrace_func_entry *entry)
1177{
1178 hlist_del(&entry->hlist);
1179 kfree(entry);
1180 hash->count--;
1181}
1182
1183static void
1184remove_hash_entry(struct ftrace_hash *hash,
1185 struct ftrace_func_entry *entry)
1186{
1187 hlist_del_rcu(&entry->hlist);
1188 hash->count--;
1189}
1190
1191static void ftrace_hash_clear(struct ftrace_hash *hash)
1192{
1193 struct hlist_head *hhd;
1194 struct hlist_node *tn;
1195 struct ftrace_func_entry *entry;
1196 int size = 1 << hash->size_bits;
1197 int i;
1198
1199 if (!hash->count)
1200 return;
1201
1202 for (i = 0; i < size; i++) {
1203 hhd = &hash->buckets[i];
1204 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1205 free_hash_entry(hash, entry);
1206 }
1207 FTRACE_WARN_ON(hash->count);
1208}
1209
1210static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1211{
1212 list_del(&ftrace_mod->list);
1213 kfree(ftrace_mod->module);
1214 kfree(ftrace_mod->func);
1215 kfree(ftrace_mod);
1216}
1217
1218static void clear_ftrace_mod_list(struct list_head *head)
1219{
1220 struct ftrace_mod_load *p, *n;
1221
1222 /* stack tracer isn't supported yet */
1223 if (!head)
1224 return;
1225
1226 mutex_lock(&ftrace_lock);
1227 list_for_each_entry_safe(p, n, head, list)
1228 free_ftrace_mod(p);
1229 mutex_unlock(&ftrace_lock);
1230}
1231
1232static void free_ftrace_hash(struct ftrace_hash *hash)
1233{
1234 if (!hash || hash == EMPTY_HASH)
1235 return;
1236 ftrace_hash_clear(hash);
1237 kfree(hash->buckets);
1238 kfree(hash);
1239}
1240
1241static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1242{
1243 struct ftrace_hash *hash;
1244
1245 hash = container_of(rcu, struct ftrace_hash, rcu);
1246 free_ftrace_hash(hash);
1247}
1248
1249static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1250{
1251 if (!hash || hash == EMPTY_HASH)
1252 return;
1253 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1254}
1255
1256void ftrace_free_filter(struct ftrace_ops *ops)
1257{
1258 ftrace_ops_init(ops);
1259 free_ftrace_hash(ops->func_hash->filter_hash);
1260 free_ftrace_hash(ops->func_hash->notrace_hash);
1261}
1262
1263static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1264{
1265 struct ftrace_hash *hash;
1266 int size;
1267
1268 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1269 if (!hash)
1270 return NULL;
1271
1272 size = 1 << size_bits;
1273 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1274
1275 if (!hash->buckets) {
1276 kfree(hash);
1277 return NULL;
1278 }
1279
1280 hash->size_bits = size_bits;
1281
1282 return hash;
1283}
1284
1285
1286static int ftrace_add_mod(struct trace_array *tr,
1287 const char *func, const char *module,
1288 int enable)
1289{
1290 struct ftrace_mod_load *ftrace_mod;
1291 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1292
1293 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1294 if (!ftrace_mod)
1295 return -ENOMEM;
1296
1297 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1298 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1299 ftrace_mod->enable = enable;
1300
1301 if (!ftrace_mod->func || !ftrace_mod->module)
1302 goto out_free;
1303
1304 list_add(&ftrace_mod->list, mod_head);
1305
1306 return 0;
1307
1308 out_free:
1309 free_ftrace_mod(ftrace_mod);
1310
1311 return -ENOMEM;
1312}
1313
1314static struct ftrace_hash *
1315alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1316{
1317 struct ftrace_func_entry *entry;
1318 struct ftrace_hash *new_hash;
1319 int size;
1320 int ret;
1321 int i;
1322
1323 new_hash = alloc_ftrace_hash(size_bits);
1324 if (!new_hash)
1325 return NULL;
1326
1327 if (hash)
1328 new_hash->flags = hash->flags;
1329
1330 /* Empty hash? */
1331 if (ftrace_hash_empty(hash))
1332 return new_hash;
1333
1334 size = 1 << hash->size_bits;
1335 for (i = 0; i < size; i++) {
1336 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1337 ret = add_hash_entry(new_hash, entry->ip);
1338 if (ret < 0)
1339 goto free_hash;
1340 }
1341 }
1342
1343 FTRACE_WARN_ON(new_hash->count != hash->count);
1344
1345 return new_hash;
1346
1347 free_hash:
1348 free_ftrace_hash(new_hash);
1349 return NULL;
1350}
1351
1352static void
1353ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1354static void
1355ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1356
1357static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1358 struct ftrace_hash *new_hash);
1359
1360static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1361{
1362 struct ftrace_func_entry *entry;
1363 struct ftrace_hash *new_hash;
1364 struct hlist_head *hhd;
1365 struct hlist_node *tn;
1366 int bits = 0;
1367 int i;
1368
1369 /*
1370 * Use around half the size (max bit of it), but
1371 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1372 */
1373 bits = fls(size / 2);
1374
1375 /* Don't allocate too much */
1376 if (bits > FTRACE_HASH_MAX_BITS)
1377 bits = FTRACE_HASH_MAX_BITS;
1378
1379 new_hash = alloc_ftrace_hash(bits);
1380 if (!new_hash)
1381 return NULL;
1382
1383 new_hash->flags = src->flags;
1384
1385 size = 1 << src->size_bits;
1386 for (i = 0; i < size; i++) {
1387 hhd = &src->buckets[i];
1388 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1389 remove_hash_entry(src, entry);
1390 __add_hash_entry(new_hash, entry);
1391 }
1392 }
1393 return new_hash;
1394}
1395
1396static struct ftrace_hash *
1397__ftrace_hash_move(struct ftrace_hash *src)
1398{
1399 int size = src->count;
1400
1401 /*
1402 * If the new source is empty, just return the empty_hash.
1403 */
1404 if (ftrace_hash_empty(src))
1405 return EMPTY_HASH;
1406
1407 return dup_hash(src, size);
1408}
1409
1410static int
1411ftrace_hash_move(struct ftrace_ops *ops, int enable,
1412 struct ftrace_hash **dst, struct ftrace_hash *src)
1413{
1414 struct ftrace_hash *new_hash;
1415 int ret;
1416
1417 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1418 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1419 return -EINVAL;
1420
1421 new_hash = __ftrace_hash_move(src);
1422 if (!new_hash)
1423 return -ENOMEM;
1424
1425 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1426 if (enable) {
1427 /* IPMODIFY should be updated only when filter_hash updating */
1428 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1429 if (ret < 0) {
1430 free_ftrace_hash(new_hash);
1431 return ret;
1432 }
1433 }
1434
1435 /*
1436 * Remove the current set, update the hash and add
1437 * them back.
1438 */
1439 ftrace_hash_rec_disable_modify(ops, enable);
1440
1441 rcu_assign_pointer(*dst, new_hash);
1442
1443 ftrace_hash_rec_enable_modify(ops, enable);
1444
1445 return 0;
1446}
1447
1448static bool hash_contains_ip(unsigned long ip,
1449 struct ftrace_ops_hash *hash)
1450{
1451 /*
1452 * The function record is a match if it exists in the filter
1453 * hash and not in the notrace hash. Note, an empty hash is
1454 * considered a match for the filter hash, but an empty
1455 * notrace hash is considered not in the notrace hash.
1456 */
1457 return (ftrace_hash_empty(hash->filter_hash) ||
1458 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1459 (ftrace_hash_empty(hash->notrace_hash) ||
1460 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1461}
1462
1463/*
1464 * Test the hashes for this ops to see if we want to call
1465 * the ops->func or not.
1466 *
1467 * It's a match if the ip is in the ops->filter_hash or
1468 * the filter_hash does not exist or is empty,
1469 * AND
1470 * the ip is not in the ops->notrace_hash.
1471 *
1472 * This needs to be called with preemption disabled as
1473 * the hashes are freed with call_rcu().
1474 */
1475int
1476ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1477{
1478 struct ftrace_ops_hash hash;
1479 int ret;
1480
1481#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1482 /*
1483 * There's a small race when adding ops that the ftrace handler
1484 * that wants regs, may be called without them. We can not
1485 * allow that handler to be called if regs is NULL.
1486 */
1487 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1488 return 0;
1489#endif
1490
1491 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1492 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1493
1494 if (hash_contains_ip(ip, &hash))
1495 ret = 1;
1496 else
1497 ret = 0;
1498
1499 return ret;
1500}
1501
1502/*
1503 * This is a double for. Do not use 'break' to break out of the loop,
1504 * you must use a goto.
1505 */
1506#define do_for_each_ftrace_rec(pg, rec) \
1507 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1508 int _____i; \
1509 for (_____i = 0; _____i < pg->index; _____i++) { \
1510 rec = &pg->records[_____i];
1511
1512#define while_for_each_ftrace_rec() \
1513 } \
1514 }
1515
1516
1517static int ftrace_cmp_recs(const void *a, const void *b)
1518{
1519 const struct dyn_ftrace *key = a;
1520 const struct dyn_ftrace *rec = b;
1521
1522 if (key->flags < rec->ip)
1523 return -1;
1524 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1525 return 1;
1526 return 0;
1527}
1528
1529static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1530{
1531 struct ftrace_page *pg;
1532 struct dyn_ftrace *rec = NULL;
1533 struct dyn_ftrace key;
1534
1535 key.ip = start;
1536 key.flags = end; /* overload flags, as it is unsigned long */
1537
1538 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1539 if (end < pg->records[0].ip ||
1540 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1541 continue;
1542 rec = bsearch(&key, pg->records, pg->index,
1543 sizeof(struct dyn_ftrace),
1544 ftrace_cmp_recs);
1545 if (rec)
1546 break;
1547 }
1548 return rec;
1549}
1550
1551/**
1552 * ftrace_location_range - return the first address of a traced location
1553 * if it touches the given ip range
1554 * @start: start of range to search.
1555 * @end: end of range to search (inclusive). @end points to the last byte
1556 * to check.
1557 *
1558 * Returns rec->ip if the related ftrace location is a least partly within
1559 * the given address range. That is, the first address of the instruction
1560 * that is either a NOP or call to the function tracer. It checks the ftrace
1561 * internal tables to determine if the address belongs or not.
1562 */
1563unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1564{
1565 struct dyn_ftrace *rec;
1566
1567 rec = lookup_rec(start, end);
1568 if (rec)
1569 return rec->ip;
1570
1571 return 0;
1572}
1573
1574/**
1575 * ftrace_location - return true if the ip giving is a traced location
1576 * @ip: the instruction pointer to check
1577 *
1578 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1579 * That is, the instruction that is either a NOP or call to
1580 * the function tracer. It checks the ftrace internal tables to
1581 * determine if the address belongs or not.
1582 */
1583unsigned long ftrace_location(unsigned long ip)
1584{
1585 return ftrace_location_range(ip, ip);
1586}
1587
1588/**
1589 * ftrace_text_reserved - return true if range contains an ftrace location
1590 * @start: start of range to search
1591 * @end: end of range to search (inclusive). @end points to the last byte to check.
1592 *
1593 * Returns 1 if @start and @end contains a ftrace location.
1594 * That is, the instruction that is either a NOP or call to
1595 * the function tracer. It checks the ftrace internal tables to
1596 * determine if the address belongs or not.
1597 */
1598int ftrace_text_reserved(const void *start, const void *end)
1599{
1600 unsigned long ret;
1601
1602 ret = ftrace_location_range((unsigned long)start,
1603 (unsigned long)end);
1604
1605 return (int)!!ret;
1606}
1607
1608/* Test if ops registered to this rec needs regs */
1609static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1610{
1611 struct ftrace_ops *ops;
1612 bool keep_regs = false;
1613
1614 for (ops = ftrace_ops_list;
1615 ops != &ftrace_list_end; ops = ops->next) {
1616 /* pass rec in as regs to have non-NULL val */
1617 if (ftrace_ops_test(ops, rec->ip, rec)) {
1618 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1619 keep_regs = true;
1620 break;
1621 }
1622 }
1623 }
1624
1625 return keep_regs;
1626}
1627
1628static struct ftrace_ops *
1629ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1630static struct ftrace_ops *
1631ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1632static struct ftrace_ops *
1633ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1634
1635static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1636 int filter_hash,
1637 bool inc)
1638{
1639 struct ftrace_hash *hash;
1640 struct ftrace_hash *other_hash;
1641 struct ftrace_page *pg;
1642 struct dyn_ftrace *rec;
1643 bool update = false;
1644 int count = 0;
1645 int all = false;
1646
1647 /* Only update if the ops has been registered */
1648 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1649 return false;
1650
1651 /*
1652 * In the filter_hash case:
1653 * If the count is zero, we update all records.
1654 * Otherwise we just update the items in the hash.
1655 *
1656 * In the notrace_hash case:
1657 * We enable the update in the hash.
1658 * As disabling notrace means enabling the tracing,
1659 * and enabling notrace means disabling, the inc variable
1660 * gets inversed.
1661 */
1662 if (filter_hash) {
1663 hash = ops->func_hash->filter_hash;
1664 other_hash = ops->func_hash->notrace_hash;
1665 if (ftrace_hash_empty(hash))
1666 all = true;
1667 } else {
1668 inc = !inc;
1669 hash = ops->func_hash->notrace_hash;
1670 other_hash = ops->func_hash->filter_hash;
1671 /*
1672 * If the notrace hash has no items,
1673 * then there's nothing to do.
1674 */
1675 if (ftrace_hash_empty(hash))
1676 return false;
1677 }
1678
1679 do_for_each_ftrace_rec(pg, rec) {
1680 int in_other_hash = 0;
1681 int in_hash = 0;
1682 int match = 0;
1683
1684 if (rec->flags & FTRACE_FL_DISABLED)
1685 continue;
1686
1687 if (all) {
1688 /*
1689 * Only the filter_hash affects all records.
1690 * Update if the record is not in the notrace hash.
1691 */
1692 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1693 match = 1;
1694 } else {
1695 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1696 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1697
1698 /*
1699 * If filter_hash is set, we want to match all functions
1700 * that are in the hash but not in the other hash.
1701 *
1702 * If filter_hash is not set, then we are decrementing.
1703 * That means we match anything that is in the hash
1704 * and also in the other_hash. That is, we need to turn
1705 * off functions in the other hash because they are disabled
1706 * by this hash.
1707 */
1708 if (filter_hash && in_hash && !in_other_hash)
1709 match = 1;
1710 else if (!filter_hash && in_hash &&
1711 (in_other_hash || ftrace_hash_empty(other_hash)))
1712 match = 1;
1713 }
1714 if (!match)
1715 continue;
1716
1717 if (inc) {
1718 rec->flags++;
1719 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1720 return false;
1721
1722 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1723 rec->flags |= FTRACE_FL_DIRECT;
1724
1725 /*
1726 * If there's only a single callback registered to a
1727 * function, and the ops has a trampoline registered
1728 * for it, then we can call it directly.
1729 */
1730 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1731 rec->flags |= FTRACE_FL_TRAMP;
1732 else
1733 /*
1734 * If we are adding another function callback
1735 * to this function, and the previous had a
1736 * custom trampoline in use, then we need to go
1737 * back to the default trampoline.
1738 */
1739 rec->flags &= ~FTRACE_FL_TRAMP;
1740
1741 /*
1742 * If any ops wants regs saved for this function
1743 * then all ops will get saved regs.
1744 */
1745 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1746 rec->flags |= FTRACE_FL_REGS;
1747 } else {
1748 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1749 return false;
1750 rec->flags--;
1751
1752 /*
1753 * Only the internal direct_ops should have the
1754 * DIRECT flag set. Thus, if it is removing a
1755 * function, then that function should no longer
1756 * be direct.
1757 */
1758 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1759 rec->flags &= ~FTRACE_FL_DIRECT;
1760
1761 /*
1762 * If the rec had REGS enabled and the ops that is
1763 * being removed had REGS set, then see if there is
1764 * still any ops for this record that wants regs.
1765 * If not, we can stop recording them.
1766 */
1767 if (ftrace_rec_count(rec) > 0 &&
1768 rec->flags & FTRACE_FL_REGS &&
1769 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1770 if (!test_rec_ops_needs_regs(rec))
1771 rec->flags &= ~FTRACE_FL_REGS;
1772 }
1773
1774 /*
1775 * The TRAMP needs to be set only if rec count
1776 * is decremented to one, and the ops that is
1777 * left has a trampoline. As TRAMP can only be
1778 * enabled if there is only a single ops attached
1779 * to it.
1780 */
1781 if (ftrace_rec_count(rec) == 1 &&
1782 ftrace_find_tramp_ops_any_other(rec, ops))
1783 rec->flags |= FTRACE_FL_TRAMP;
1784 else
1785 rec->flags &= ~FTRACE_FL_TRAMP;
1786
1787 /*
1788 * flags will be cleared in ftrace_check_record()
1789 * if rec count is zero.
1790 */
1791 }
1792 count++;
1793
1794 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1795 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1796
1797 /* Shortcut, if we handled all records, we are done. */
1798 if (!all && count == hash->count)
1799 return update;
1800 } while_for_each_ftrace_rec();
1801
1802 return update;
1803}
1804
1805static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1806 int filter_hash)
1807{
1808 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1809}
1810
1811static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1812 int filter_hash)
1813{
1814 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1815}
1816
1817static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1818 int filter_hash, int inc)
1819{
1820 struct ftrace_ops *op;
1821
1822 __ftrace_hash_rec_update(ops, filter_hash, inc);
1823
1824 if (ops->func_hash != &global_ops.local_hash)
1825 return;
1826
1827 /*
1828 * If the ops shares the global_ops hash, then we need to update
1829 * all ops that are enabled and use this hash.
1830 */
1831 do_for_each_ftrace_op(op, ftrace_ops_list) {
1832 /* Already done */
1833 if (op == ops)
1834 continue;
1835 if (op->func_hash == &global_ops.local_hash)
1836 __ftrace_hash_rec_update(op, filter_hash, inc);
1837 } while_for_each_ftrace_op(op);
1838}
1839
1840static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1841 int filter_hash)
1842{
1843 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1844}
1845
1846static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1847 int filter_hash)
1848{
1849 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1850}
1851
1852/*
1853 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1854 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1855 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1856 * Note that old_hash and new_hash has below meanings
1857 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1858 * - If the hash is EMPTY_HASH, it hits nothing
1859 * - Anything else hits the recs which match the hash entries.
1860 */
1861static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1862 struct ftrace_hash *old_hash,
1863 struct ftrace_hash *new_hash)
1864{
1865 struct ftrace_page *pg;
1866 struct dyn_ftrace *rec, *end = NULL;
1867 int in_old, in_new;
1868
1869 /* Only update if the ops has been registered */
1870 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1871 return 0;
1872
1873 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1874 return 0;
1875
1876 /*
1877 * Since the IPMODIFY is a very address sensitive action, we do not
1878 * allow ftrace_ops to set all functions to new hash.
1879 */
1880 if (!new_hash || !old_hash)
1881 return -EINVAL;
1882
1883 /* Update rec->flags */
1884 do_for_each_ftrace_rec(pg, rec) {
1885
1886 if (rec->flags & FTRACE_FL_DISABLED)
1887 continue;
1888
1889 /* We need to update only differences of filter_hash */
1890 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1891 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1892 if (in_old == in_new)
1893 continue;
1894
1895 if (in_new) {
1896 /* New entries must ensure no others are using it */
1897 if (rec->flags & FTRACE_FL_IPMODIFY)
1898 goto rollback;
1899 rec->flags |= FTRACE_FL_IPMODIFY;
1900 } else /* Removed entry */
1901 rec->flags &= ~FTRACE_FL_IPMODIFY;
1902 } while_for_each_ftrace_rec();
1903
1904 return 0;
1905
1906rollback:
1907 end = rec;
1908
1909 /* Roll back what we did above */
1910 do_for_each_ftrace_rec(pg, rec) {
1911
1912 if (rec->flags & FTRACE_FL_DISABLED)
1913 continue;
1914
1915 if (rec == end)
1916 goto err_out;
1917
1918 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1919 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1920 if (in_old == in_new)
1921 continue;
1922
1923 if (in_new)
1924 rec->flags &= ~FTRACE_FL_IPMODIFY;
1925 else
1926 rec->flags |= FTRACE_FL_IPMODIFY;
1927 } while_for_each_ftrace_rec();
1928
1929err_out:
1930 return -EBUSY;
1931}
1932
1933static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1934{
1935 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1936
1937 if (ftrace_hash_empty(hash))
1938 hash = NULL;
1939
1940 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1941}
1942
1943/* Disabling always succeeds */
1944static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1945{
1946 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1947
1948 if (ftrace_hash_empty(hash))
1949 hash = NULL;
1950
1951 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1952}
1953
1954static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1955 struct ftrace_hash *new_hash)
1956{
1957 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1958
1959 if (ftrace_hash_empty(old_hash))
1960 old_hash = NULL;
1961
1962 if (ftrace_hash_empty(new_hash))
1963 new_hash = NULL;
1964
1965 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1966}
1967
1968static void print_ip_ins(const char *fmt, const unsigned char *p)
1969{
1970 char ins[MCOUNT_INSN_SIZE];
1971 int i;
1972
1973 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
1974 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
1975 return;
1976 }
1977
1978 printk(KERN_CONT "%s", fmt);
1979
1980 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1981 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
1982}
1983
1984enum ftrace_bug_type ftrace_bug_type;
1985const void *ftrace_expected;
1986
1987static void print_bug_type(void)
1988{
1989 switch (ftrace_bug_type) {
1990 case FTRACE_BUG_UNKNOWN:
1991 break;
1992 case FTRACE_BUG_INIT:
1993 pr_info("Initializing ftrace call sites\n");
1994 break;
1995 case FTRACE_BUG_NOP:
1996 pr_info("Setting ftrace call site to NOP\n");
1997 break;
1998 case FTRACE_BUG_CALL:
1999 pr_info("Setting ftrace call site to call ftrace function\n");
2000 break;
2001 case FTRACE_BUG_UPDATE:
2002 pr_info("Updating ftrace call site to call a different ftrace function\n");
2003 break;
2004 }
2005}
2006
2007/**
2008 * ftrace_bug - report and shutdown function tracer
2009 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2010 * @rec: The record that failed
2011 *
2012 * The arch code that enables or disables the function tracing
2013 * can call ftrace_bug() when it has detected a problem in
2014 * modifying the code. @failed should be one of either:
2015 * EFAULT - if the problem happens on reading the @ip address
2016 * EINVAL - if what is read at @ip is not what was expected
2017 * EPERM - if the problem happens on writing to the @ip address
2018 */
2019void ftrace_bug(int failed, struct dyn_ftrace *rec)
2020{
2021 unsigned long ip = rec ? rec->ip : 0;
2022
2023 pr_info("------------[ ftrace bug ]------------\n");
2024
2025 switch (failed) {
2026 case -EFAULT:
2027 pr_info("ftrace faulted on modifying ");
2028 print_ip_sym(KERN_INFO, ip);
2029 break;
2030 case -EINVAL:
2031 pr_info("ftrace failed to modify ");
2032 print_ip_sym(KERN_INFO, ip);
2033 print_ip_ins(" actual: ", (unsigned char *)ip);
2034 pr_cont("\n");
2035 if (ftrace_expected) {
2036 print_ip_ins(" expected: ", ftrace_expected);
2037 pr_cont("\n");
2038 }
2039 break;
2040 case -EPERM:
2041 pr_info("ftrace faulted on writing ");
2042 print_ip_sym(KERN_INFO, ip);
2043 break;
2044 default:
2045 pr_info("ftrace faulted on unknown error ");
2046 print_ip_sym(KERN_INFO, ip);
2047 }
2048 print_bug_type();
2049 if (rec) {
2050 struct ftrace_ops *ops = NULL;
2051
2052 pr_info("ftrace record flags: %lx\n", rec->flags);
2053 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2054 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2055 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2056 ops = ftrace_find_tramp_ops_any(rec);
2057 if (ops) {
2058 do {
2059 pr_cont("\ttramp: %pS (%pS)",
2060 (void *)ops->trampoline,
2061 (void *)ops->func);
2062 ops = ftrace_find_tramp_ops_next(rec, ops);
2063 } while (ops);
2064 } else
2065 pr_cont("\ttramp: ERROR!");
2066
2067 }
2068 ip = ftrace_get_addr_curr(rec);
2069 pr_cont("\n expected tramp: %lx\n", ip);
2070 }
2071
2072 FTRACE_WARN_ON_ONCE(1);
2073}
2074
2075static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2076{
2077 unsigned long flag = 0UL;
2078
2079 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2080
2081 if (rec->flags & FTRACE_FL_DISABLED)
2082 return FTRACE_UPDATE_IGNORE;
2083
2084 /*
2085 * If we are updating calls:
2086 *
2087 * If the record has a ref count, then we need to enable it
2088 * because someone is using it.
2089 *
2090 * Otherwise we make sure its disabled.
2091 *
2092 * If we are disabling calls, then disable all records that
2093 * are enabled.
2094 */
2095 if (enable && ftrace_rec_count(rec))
2096 flag = FTRACE_FL_ENABLED;
2097
2098 /*
2099 * If enabling and the REGS flag does not match the REGS_EN, or
2100 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2101 * this record. Set flags to fail the compare against ENABLED.
2102 * Same for direct calls.
2103 */
2104 if (flag) {
2105 if (!(rec->flags & FTRACE_FL_REGS) !=
2106 !(rec->flags & FTRACE_FL_REGS_EN))
2107 flag |= FTRACE_FL_REGS;
2108
2109 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2110 !(rec->flags & FTRACE_FL_TRAMP_EN))
2111 flag |= FTRACE_FL_TRAMP;
2112
2113 /*
2114 * Direct calls are special, as count matters.
2115 * We must test the record for direct, if the
2116 * DIRECT and DIRECT_EN do not match, but only
2117 * if the count is 1. That's because, if the
2118 * count is something other than one, we do not
2119 * want the direct enabled (it will be done via the
2120 * direct helper). But if DIRECT_EN is set, and
2121 * the count is not one, we need to clear it.
2122 */
2123 if (ftrace_rec_count(rec) == 1) {
2124 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2125 !(rec->flags & FTRACE_FL_DIRECT_EN))
2126 flag |= FTRACE_FL_DIRECT;
2127 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2128 flag |= FTRACE_FL_DIRECT;
2129 }
2130 }
2131
2132 /* If the state of this record hasn't changed, then do nothing */
2133 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2134 return FTRACE_UPDATE_IGNORE;
2135
2136 if (flag) {
2137 /* Save off if rec is being enabled (for return value) */
2138 flag ^= rec->flags & FTRACE_FL_ENABLED;
2139
2140 if (update) {
2141 rec->flags |= FTRACE_FL_ENABLED;
2142 if (flag & FTRACE_FL_REGS) {
2143 if (rec->flags & FTRACE_FL_REGS)
2144 rec->flags |= FTRACE_FL_REGS_EN;
2145 else
2146 rec->flags &= ~FTRACE_FL_REGS_EN;
2147 }
2148 if (flag & FTRACE_FL_TRAMP) {
2149 if (rec->flags & FTRACE_FL_TRAMP)
2150 rec->flags |= FTRACE_FL_TRAMP_EN;
2151 else
2152 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2153 }
2154
2155 if (flag & FTRACE_FL_DIRECT) {
2156 /*
2157 * If there's only one user (direct_ops helper)
2158 * then we can call the direct function
2159 * directly (no ftrace trampoline).
2160 */
2161 if (ftrace_rec_count(rec) == 1) {
2162 if (rec->flags & FTRACE_FL_DIRECT)
2163 rec->flags |= FTRACE_FL_DIRECT_EN;
2164 else
2165 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2166 } else {
2167 /*
2168 * Can only call directly if there's
2169 * only one callback to the function.
2170 */
2171 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2172 }
2173 }
2174 }
2175
2176 /*
2177 * If this record is being updated from a nop, then
2178 * return UPDATE_MAKE_CALL.
2179 * Otherwise,
2180 * return UPDATE_MODIFY_CALL to tell the caller to convert
2181 * from the save regs, to a non-save regs function or
2182 * vice versa, or from a trampoline call.
2183 */
2184 if (flag & FTRACE_FL_ENABLED) {
2185 ftrace_bug_type = FTRACE_BUG_CALL;
2186 return FTRACE_UPDATE_MAKE_CALL;
2187 }
2188
2189 ftrace_bug_type = FTRACE_BUG_UPDATE;
2190 return FTRACE_UPDATE_MODIFY_CALL;
2191 }
2192
2193 if (update) {
2194 /* If there's no more users, clear all flags */
2195 if (!ftrace_rec_count(rec))
2196 rec->flags = 0;
2197 else
2198 /*
2199 * Just disable the record, but keep the ops TRAMP
2200 * and REGS states. The _EN flags must be disabled though.
2201 */
2202 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2203 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2204 }
2205
2206 ftrace_bug_type = FTRACE_BUG_NOP;
2207 return FTRACE_UPDATE_MAKE_NOP;
2208}
2209
2210/**
2211 * ftrace_update_record, set a record that now is tracing or not
2212 * @rec: the record to update
2213 * @enable: set to true if the record is tracing, false to force disable
2214 *
2215 * The records that represent all functions that can be traced need
2216 * to be updated when tracing has been enabled.
2217 */
2218int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2219{
2220 return ftrace_check_record(rec, enable, true);
2221}
2222
2223/**
2224 * ftrace_test_record, check if the record has been enabled or not
2225 * @rec: the record to test
2226 * @enable: set to true to check if enabled, false if it is disabled
2227 *
2228 * The arch code may need to test if a record is already set to
2229 * tracing to determine how to modify the function code that it
2230 * represents.
2231 */
2232int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2233{
2234 return ftrace_check_record(rec, enable, false);
2235}
2236
2237static struct ftrace_ops *
2238ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2239{
2240 struct ftrace_ops *op;
2241 unsigned long ip = rec->ip;
2242
2243 do_for_each_ftrace_op(op, ftrace_ops_list) {
2244
2245 if (!op->trampoline)
2246 continue;
2247
2248 if (hash_contains_ip(ip, op->func_hash))
2249 return op;
2250 } while_for_each_ftrace_op(op);
2251
2252 return NULL;
2253}
2254
2255static struct ftrace_ops *
2256ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2257{
2258 struct ftrace_ops *op;
2259 unsigned long ip = rec->ip;
2260
2261 do_for_each_ftrace_op(op, ftrace_ops_list) {
2262
2263 if (op == op_exclude || !op->trampoline)
2264 continue;
2265
2266 if (hash_contains_ip(ip, op->func_hash))
2267 return op;
2268 } while_for_each_ftrace_op(op);
2269
2270 return NULL;
2271}
2272
2273static struct ftrace_ops *
2274ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2275 struct ftrace_ops *op)
2276{
2277 unsigned long ip = rec->ip;
2278
2279 while_for_each_ftrace_op(op) {
2280
2281 if (!op->trampoline)
2282 continue;
2283
2284 if (hash_contains_ip(ip, op->func_hash))
2285 return op;
2286 }
2287
2288 return NULL;
2289}
2290
2291static struct ftrace_ops *
2292ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2293{
2294 struct ftrace_ops *op;
2295 unsigned long ip = rec->ip;
2296
2297 /*
2298 * Need to check removed ops first.
2299 * If they are being removed, and this rec has a tramp,
2300 * and this rec is in the ops list, then it would be the
2301 * one with the tramp.
2302 */
2303 if (removed_ops) {
2304 if (hash_contains_ip(ip, &removed_ops->old_hash))
2305 return removed_ops;
2306 }
2307
2308 /*
2309 * Need to find the current trampoline for a rec.
2310 * Now, a trampoline is only attached to a rec if there
2311 * was a single 'ops' attached to it. But this can be called
2312 * when we are adding another op to the rec or removing the
2313 * current one. Thus, if the op is being added, we can
2314 * ignore it because it hasn't attached itself to the rec
2315 * yet.
2316 *
2317 * If an ops is being modified (hooking to different functions)
2318 * then we don't care about the new functions that are being
2319 * added, just the old ones (that are probably being removed).
2320 *
2321 * If we are adding an ops to a function that already is using
2322 * a trampoline, it needs to be removed (trampolines are only
2323 * for single ops connected), then an ops that is not being
2324 * modified also needs to be checked.
2325 */
2326 do_for_each_ftrace_op(op, ftrace_ops_list) {
2327
2328 if (!op->trampoline)
2329 continue;
2330
2331 /*
2332 * If the ops is being added, it hasn't gotten to
2333 * the point to be removed from this tree yet.
2334 */
2335 if (op->flags & FTRACE_OPS_FL_ADDING)
2336 continue;
2337
2338
2339 /*
2340 * If the ops is being modified and is in the old
2341 * hash, then it is probably being removed from this
2342 * function.
2343 */
2344 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2345 hash_contains_ip(ip, &op->old_hash))
2346 return op;
2347 /*
2348 * If the ops is not being added or modified, and it's
2349 * in its normal filter hash, then this must be the one
2350 * we want!
2351 */
2352 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2353 hash_contains_ip(ip, op->func_hash))
2354 return op;
2355
2356 } while_for_each_ftrace_op(op);
2357
2358 return NULL;
2359}
2360
2361static struct ftrace_ops *
2362ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2363{
2364 struct ftrace_ops *op;
2365 unsigned long ip = rec->ip;
2366
2367 do_for_each_ftrace_op(op, ftrace_ops_list) {
2368 /* pass rec in as regs to have non-NULL val */
2369 if (hash_contains_ip(ip, op->func_hash))
2370 return op;
2371 } while_for_each_ftrace_op(op);
2372
2373 return NULL;
2374}
2375
2376#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2377/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2378static struct ftrace_hash *direct_functions = EMPTY_HASH;
2379static DEFINE_MUTEX(direct_mutex);
2380int ftrace_direct_func_count;
2381
2382/*
2383 * Search the direct_functions hash to see if the given instruction pointer
2384 * has a direct caller attached to it.
2385 */
2386unsigned long ftrace_find_rec_direct(unsigned long ip)
2387{
2388 struct ftrace_func_entry *entry;
2389
2390 entry = __ftrace_lookup_ip(direct_functions, ip);
2391 if (!entry)
2392 return 0;
2393
2394 return entry->direct;
2395}
2396
2397static void call_direct_funcs(unsigned long ip, unsigned long pip,
2398 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2399{
2400 struct pt_regs *regs = ftrace_get_regs(fregs);
2401 unsigned long addr;
2402
2403 addr = ftrace_find_rec_direct(ip);
2404 if (!addr)
2405 return;
2406
2407 arch_ftrace_set_direct_caller(regs, addr);
2408}
2409
2410struct ftrace_ops direct_ops = {
2411 .func = call_direct_funcs,
2412 .flags = FTRACE_OPS_FL_IPMODIFY
2413 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2414 | FTRACE_OPS_FL_PERMANENT,
2415 /*
2416 * By declaring the main trampoline as this trampoline
2417 * it will never have one allocated for it. Allocated
2418 * trampolines should not call direct functions.
2419 * The direct_ops should only be called by the builtin
2420 * ftrace_regs_caller trampoline.
2421 */
2422 .trampoline = FTRACE_REGS_ADDR,
2423};
2424#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2425
2426/**
2427 * ftrace_get_addr_new - Get the call address to set to
2428 * @rec: The ftrace record descriptor
2429 *
2430 * If the record has the FTRACE_FL_REGS set, that means that it
2431 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2432 * is not set, then it wants to convert to the normal callback.
2433 *
2434 * Returns the address of the trampoline to set to
2435 */
2436unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2437{
2438 struct ftrace_ops *ops;
2439 unsigned long addr;
2440
2441 if ((rec->flags & FTRACE_FL_DIRECT) &&
2442 (ftrace_rec_count(rec) == 1)) {
2443 addr = ftrace_find_rec_direct(rec->ip);
2444 if (addr)
2445 return addr;
2446 WARN_ON_ONCE(1);
2447 }
2448
2449 /* Trampolines take precedence over regs */
2450 if (rec->flags & FTRACE_FL_TRAMP) {
2451 ops = ftrace_find_tramp_ops_new(rec);
2452 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2453 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2454 (void *)rec->ip, (void *)rec->ip, rec->flags);
2455 /* Ftrace is shutting down, return anything */
2456 return (unsigned long)FTRACE_ADDR;
2457 }
2458 return ops->trampoline;
2459 }
2460
2461 if (rec->flags & FTRACE_FL_REGS)
2462 return (unsigned long)FTRACE_REGS_ADDR;
2463 else
2464 return (unsigned long)FTRACE_ADDR;
2465}
2466
2467/**
2468 * ftrace_get_addr_curr - Get the call address that is already there
2469 * @rec: The ftrace record descriptor
2470 *
2471 * The FTRACE_FL_REGS_EN is set when the record already points to
2472 * a function that saves all the regs. Basically the '_EN' version
2473 * represents the current state of the function.
2474 *
2475 * Returns the address of the trampoline that is currently being called
2476 */
2477unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2478{
2479 struct ftrace_ops *ops;
2480 unsigned long addr;
2481
2482 /* Direct calls take precedence over trampolines */
2483 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2484 addr = ftrace_find_rec_direct(rec->ip);
2485 if (addr)
2486 return addr;
2487 WARN_ON_ONCE(1);
2488 }
2489
2490 /* Trampolines take precedence over regs */
2491 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2492 ops = ftrace_find_tramp_ops_curr(rec);
2493 if (FTRACE_WARN_ON(!ops)) {
2494 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2495 (void *)rec->ip, (void *)rec->ip);
2496 /* Ftrace is shutting down, return anything */
2497 return (unsigned long)FTRACE_ADDR;
2498 }
2499 return ops->trampoline;
2500 }
2501
2502 if (rec->flags & FTRACE_FL_REGS_EN)
2503 return (unsigned long)FTRACE_REGS_ADDR;
2504 else
2505 return (unsigned long)FTRACE_ADDR;
2506}
2507
2508static int
2509__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2510{
2511 unsigned long ftrace_old_addr;
2512 unsigned long ftrace_addr;
2513 int ret;
2514
2515 ftrace_addr = ftrace_get_addr_new(rec);
2516
2517 /* This needs to be done before we call ftrace_update_record */
2518 ftrace_old_addr = ftrace_get_addr_curr(rec);
2519
2520 ret = ftrace_update_record(rec, enable);
2521
2522 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2523
2524 switch (ret) {
2525 case FTRACE_UPDATE_IGNORE:
2526 return 0;
2527
2528 case FTRACE_UPDATE_MAKE_CALL:
2529 ftrace_bug_type = FTRACE_BUG_CALL;
2530 return ftrace_make_call(rec, ftrace_addr);
2531
2532 case FTRACE_UPDATE_MAKE_NOP:
2533 ftrace_bug_type = FTRACE_BUG_NOP;
2534 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2535
2536 case FTRACE_UPDATE_MODIFY_CALL:
2537 ftrace_bug_type = FTRACE_BUG_UPDATE;
2538 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2539 }
2540
2541 return -1; /* unknown ftrace bug */
2542}
2543
2544void __weak ftrace_replace_code(int mod_flags)
2545{
2546 struct dyn_ftrace *rec;
2547 struct ftrace_page *pg;
2548 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2549 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2550 int failed;
2551
2552 if (unlikely(ftrace_disabled))
2553 return;
2554
2555 do_for_each_ftrace_rec(pg, rec) {
2556
2557 if (rec->flags & FTRACE_FL_DISABLED)
2558 continue;
2559
2560 failed = __ftrace_replace_code(rec, enable);
2561 if (failed) {
2562 ftrace_bug(failed, rec);
2563 /* Stop processing */
2564 return;
2565 }
2566 if (schedulable)
2567 cond_resched();
2568 } while_for_each_ftrace_rec();
2569}
2570
2571struct ftrace_rec_iter {
2572 struct ftrace_page *pg;
2573 int index;
2574};
2575
2576/**
2577 * ftrace_rec_iter_start, start up iterating over traced functions
2578 *
2579 * Returns an iterator handle that is used to iterate over all
2580 * the records that represent address locations where functions
2581 * are traced.
2582 *
2583 * May return NULL if no records are available.
2584 */
2585struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2586{
2587 /*
2588 * We only use a single iterator.
2589 * Protected by the ftrace_lock mutex.
2590 */
2591 static struct ftrace_rec_iter ftrace_rec_iter;
2592 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2593
2594 iter->pg = ftrace_pages_start;
2595 iter->index = 0;
2596
2597 /* Could have empty pages */
2598 while (iter->pg && !iter->pg->index)
2599 iter->pg = iter->pg->next;
2600
2601 if (!iter->pg)
2602 return NULL;
2603
2604 return iter;
2605}
2606
2607/**
2608 * ftrace_rec_iter_next, get the next record to process.
2609 * @iter: The handle to the iterator.
2610 *
2611 * Returns the next iterator after the given iterator @iter.
2612 */
2613struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2614{
2615 iter->index++;
2616
2617 if (iter->index >= iter->pg->index) {
2618 iter->pg = iter->pg->next;
2619 iter->index = 0;
2620
2621 /* Could have empty pages */
2622 while (iter->pg && !iter->pg->index)
2623 iter->pg = iter->pg->next;
2624 }
2625
2626 if (!iter->pg)
2627 return NULL;
2628
2629 return iter;
2630}
2631
2632/**
2633 * ftrace_rec_iter_record, get the record at the iterator location
2634 * @iter: The current iterator location
2635 *
2636 * Returns the record that the current @iter is at.
2637 */
2638struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2639{
2640 return &iter->pg->records[iter->index];
2641}
2642
2643static int
2644ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2645{
2646 int ret;
2647
2648 if (unlikely(ftrace_disabled))
2649 return 0;
2650
2651 ret = ftrace_init_nop(mod, rec);
2652 if (ret) {
2653 ftrace_bug_type = FTRACE_BUG_INIT;
2654 ftrace_bug(ret, rec);
2655 return 0;
2656 }
2657 return 1;
2658}
2659
2660/*
2661 * archs can override this function if they must do something
2662 * before the modifying code is performed.
2663 */
2664int __weak ftrace_arch_code_modify_prepare(void)
2665{
2666 return 0;
2667}
2668
2669/*
2670 * archs can override this function if they must do something
2671 * after the modifying code is performed.
2672 */
2673int __weak ftrace_arch_code_modify_post_process(void)
2674{
2675 return 0;
2676}
2677
2678void ftrace_modify_all_code(int command)
2679{
2680 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2681 int mod_flags = 0;
2682 int err = 0;
2683
2684 if (command & FTRACE_MAY_SLEEP)
2685 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2686
2687 /*
2688 * If the ftrace_caller calls a ftrace_ops func directly,
2689 * we need to make sure that it only traces functions it
2690 * expects to trace. When doing the switch of functions,
2691 * we need to update to the ftrace_ops_list_func first
2692 * before the transition between old and new calls are set,
2693 * as the ftrace_ops_list_func will check the ops hashes
2694 * to make sure the ops are having the right functions
2695 * traced.
2696 */
2697 if (update) {
2698 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2699 if (FTRACE_WARN_ON(err))
2700 return;
2701 }
2702
2703 if (command & FTRACE_UPDATE_CALLS)
2704 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2705 else if (command & FTRACE_DISABLE_CALLS)
2706 ftrace_replace_code(mod_flags);
2707
2708 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2709 function_trace_op = set_function_trace_op;
2710 smp_wmb();
2711 /* If irqs are disabled, we are in stop machine */
2712 if (!irqs_disabled())
2713 smp_call_function(ftrace_sync_ipi, NULL, 1);
2714 err = ftrace_update_ftrace_func(ftrace_trace_function);
2715 if (FTRACE_WARN_ON(err))
2716 return;
2717 }
2718
2719 if (command & FTRACE_START_FUNC_RET)
2720 err = ftrace_enable_ftrace_graph_caller();
2721 else if (command & FTRACE_STOP_FUNC_RET)
2722 err = ftrace_disable_ftrace_graph_caller();
2723 FTRACE_WARN_ON(err);
2724}
2725
2726static int __ftrace_modify_code(void *data)
2727{
2728 int *command = data;
2729
2730 ftrace_modify_all_code(*command);
2731
2732 return 0;
2733}
2734
2735/**
2736 * ftrace_run_stop_machine, go back to the stop machine method
2737 * @command: The command to tell ftrace what to do
2738 *
2739 * If an arch needs to fall back to the stop machine method, the
2740 * it can call this function.
2741 */
2742void ftrace_run_stop_machine(int command)
2743{
2744 stop_machine(__ftrace_modify_code, &command, NULL);
2745}
2746
2747/**
2748 * arch_ftrace_update_code, modify the code to trace or not trace
2749 * @command: The command that needs to be done
2750 *
2751 * Archs can override this function if it does not need to
2752 * run stop_machine() to modify code.
2753 */
2754void __weak arch_ftrace_update_code(int command)
2755{
2756 ftrace_run_stop_machine(command);
2757}
2758
2759static void ftrace_run_update_code(int command)
2760{
2761 int ret;
2762
2763 ret = ftrace_arch_code_modify_prepare();
2764 FTRACE_WARN_ON(ret);
2765 if (ret)
2766 return;
2767
2768 /*
2769 * By default we use stop_machine() to modify the code.
2770 * But archs can do what ever they want as long as it
2771 * is safe. The stop_machine() is the safest, but also
2772 * produces the most overhead.
2773 */
2774 arch_ftrace_update_code(command);
2775
2776 ret = ftrace_arch_code_modify_post_process();
2777 FTRACE_WARN_ON(ret);
2778}
2779
2780static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2781 struct ftrace_ops_hash *old_hash)
2782{
2783 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2784 ops->old_hash.filter_hash = old_hash->filter_hash;
2785 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2786 ftrace_run_update_code(command);
2787 ops->old_hash.filter_hash = NULL;
2788 ops->old_hash.notrace_hash = NULL;
2789 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2790}
2791
2792static ftrace_func_t saved_ftrace_func;
2793static int ftrace_start_up;
2794
2795void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2796{
2797}
2798
2799/* List of trace_ops that have allocated trampolines */
2800static LIST_HEAD(ftrace_ops_trampoline_list);
2801
2802static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2803{
2804 lockdep_assert_held(&ftrace_lock);
2805 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2806}
2807
2808static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2809{
2810 lockdep_assert_held(&ftrace_lock);
2811 list_del_rcu(&ops->list);
2812 synchronize_rcu();
2813}
2814
2815/*
2816 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2817 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2818 * not a module.
2819 */
2820#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2821#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2822
2823static void ftrace_trampoline_free(struct ftrace_ops *ops)
2824{
2825 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2826 ops->trampoline) {
2827 /*
2828 * Record the text poke event before the ksymbol unregister
2829 * event.
2830 */
2831 perf_event_text_poke((void *)ops->trampoline,
2832 (void *)ops->trampoline,
2833 ops->trampoline_size, NULL, 0);
2834 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2835 ops->trampoline, ops->trampoline_size,
2836 true, FTRACE_TRAMPOLINE_SYM);
2837 /* Remove from kallsyms after the perf events */
2838 ftrace_remove_trampoline_from_kallsyms(ops);
2839 }
2840
2841 arch_ftrace_trampoline_free(ops);
2842}
2843
2844static void ftrace_startup_enable(int command)
2845{
2846 if (saved_ftrace_func != ftrace_trace_function) {
2847 saved_ftrace_func = ftrace_trace_function;
2848 command |= FTRACE_UPDATE_TRACE_FUNC;
2849 }
2850
2851 if (!command || !ftrace_enabled)
2852 return;
2853
2854 ftrace_run_update_code(command);
2855}
2856
2857static void ftrace_startup_all(int command)
2858{
2859 update_all_ops = true;
2860 ftrace_startup_enable(command);
2861 update_all_ops = false;
2862}
2863
2864int ftrace_startup(struct ftrace_ops *ops, int command)
2865{
2866 int ret;
2867
2868 if (unlikely(ftrace_disabled))
2869 return -ENODEV;
2870
2871 ret = __register_ftrace_function(ops);
2872 if (ret)
2873 return ret;
2874
2875 ftrace_start_up++;
2876
2877 /*
2878 * Note that ftrace probes uses this to start up
2879 * and modify functions it will probe. But we still
2880 * set the ADDING flag for modification, as probes
2881 * do not have trampolines. If they add them in the
2882 * future, then the probes will need to distinguish
2883 * between adding and updating probes.
2884 */
2885 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2886
2887 ret = ftrace_hash_ipmodify_enable(ops);
2888 if (ret < 0) {
2889 /* Rollback registration process */
2890 __unregister_ftrace_function(ops);
2891 ftrace_start_up--;
2892 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2893 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2894 ftrace_trampoline_free(ops);
2895 return ret;
2896 }
2897
2898 if (ftrace_hash_rec_enable(ops, 1))
2899 command |= FTRACE_UPDATE_CALLS;
2900
2901 ftrace_startup_enable(command);
2902
2903 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2904
2905 return 0;
2906}
2907
2908int ftrace_shutdown(struct ftrace_ops *ops, int command)
2909{
2910 int ret;
2911
2912 if (unlikely(ftrace_disabled))
2913 return -ENODEV;
2914
2915 ret = __unregister_ftrace_function(ops);
2916 if (ret)
2917 return ret;
2918
2919 ftrace_start_up--;
2920 /*
2921 * Just warn in case of unbalance, no need to kill ftrace, it's not
2922 * critical but the ftrace_call callers may be never nopped again after
2923 * further ftrace uses.
2924 */
2925 WARN_ON_ONCE(ftrace_start_up < 0);
2926
2927 /* Disabling ipmodify never fails */
2928 ftrace_hash_ipmodify_disable(ops);
2929
2930 if (ftrace_hash_rec_disable(ops, 1))
2931 command |= FTRACE_UPDATE_CALLS;
2932
2933 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2934
2935 if (saved_ftrace_func != ftrace_trace_function) {
2936 saved_ftrace_func = ftrace_trace_function;
2937 command |= FTRACE_UPDATE_TRACE_FUNC;
2938 }
2939
2940 if (!command || !ftrace_enabled) {
2941 /*
2942 * If these are dynamic or per_cpu ops, they still
2943 * need their data freed. Since, function tracing is
2944 * not currently active, we can just free them
2945 * without synchronizing all CPUs.
2946 */
2947 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2948 goto free_ops;
2949
2950 return 0;
2951 }
2952
2953 /*
2954 * If the ops uses a trampoline, then it needs to be
2955 * tested first on update.
2956 */
2957 ops->flags |= FTRACE_OPS_FL_REMOVING;
2958 removed_ops = ops;
2959
2960 /* The trampoline logic checks the old hashes */
2961 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2962 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2963
2964 ftrace_run_update_code(command);
2965
2966 /*
2967 * If there's no more ops registered with ftrace, run a
2968 * sanity check to make sure all rec flags are cleared.
2969 */
2970 if (rcu_dereference_protected(ftrace_ops_list,
2971 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2972 struct ftrace_page *pg;
2973 struct dyn_ftrace *rec;
2974
2975 do_for_each_ftrace_rec(pg, rec) {
2976 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2977 pr_warn(" %pS flags:%lx\n",
2978 (void *)rec->ip, rec->flags);
2979 } while_for_each_ftrace_rec();
2980 }
2981
2982 ops->old_hash.filter_hash = NULL;
2983 ops->old_hash.notrace_hash = NULL;
2984
2985 removed_ops = NULL;
2986 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2987
2988 /*
2989 * Dynamic ops may be freed, we must make sure that all
2990 * callers are done before leaving this function.
2991 * The same goes for freeing the per_cpu data of the per_cpu
2992 * ops.
2993 */
2994 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2995 /*
2996 * We need to do a hard force of sched synchronization.
2997 * This is because we use preempt_disable() to do RCU, but
2998 * the function tracers can be called where RCU is not watching
2999 * (like before user_exit()). We can not rely on the RCU
3000 * infrastructure to do the synchronization, thus we must do it
3001 * ourselves.
3002 */
3003 synchronize_rcu_tasks_rude();
3004
3005 /*
3006 * When the kernel is preemptive, tasks can be preempted
3007 * while on a ftrace trampoline. Just scheduling a task on
3008 * a CPU is not good enough to flush them. Calling
3009 * synchronize_rcu_tasks() will wait for those tasks to
3010 * execute and either schedule voluntarily or enter user space.
3011 */
3012 if (IS_ENABLED(CONFIG_PREEMPTION))
3013 synchronize_rcu_tasks();
3014
3015 free_ops:
3016 ftrace_trampoline_free(ops);
3017 }
3018
3019 return 0;
3020}
3021
3022static void ftrace_startup_sysctl(void)
3023{
3024 int command;
3025
3026 if (unlikely(ftrace_disabled))
3027 return;
3028
3029 /* Force update next time */
3030 saved_ftrace_func = NULL;
3031 /* ftrace_start_up is true if we want ftrace running */
3032 if (ftrace_start_up) {
3033 command = FTRACE_UPDATE_CALLS;
3034 if (ftrace_graph_active)
3035 command |= FTRACE_START_FUNC_RET;
3036 ftrace_startup_enable(command);
3037 }
3038}
3039
3040static void ftrace_shutdown_sysctl(void)
3041{
3042 int command;
3043
3044 if (unlikely(ftrace_disabled))
3045 return;
3046
3047 /* ftrace_start_up is true if ftrace is running */
3048 if (ftrace_start_up) {
3049 command = FTRACE_DISABLE_CALLS;
3050 if (ftrace_graph_active)
3051 command |= FTRACE_STOP_FUNC_RET;
3052 ftrace_run_update_code(command);
3053 }
3054}
3055
3056static u64 ftrace_update_time;
3057unsigned long ftrace_update_tot_cnt;
3058unsigned long ftrace_number_of_pages;
3059unsigned long ftrace_number_of_groups;
3060
3061static inline int ops_traces_mod(struct ftrace_ops *ops)
3062{
3063 /*
3064 * Filter_hash being empty will default to trace module.
3065 * But notrace hash requires a test of individual module functions.
3066 */
3067 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3068 ftrace_hash_empty(ops->func_hash->notrace_hash);
3069}
3070
3071/*
3072 * Check if the current ops references the record.
3073 *
3074 * If the ops traces all functions, then it was already accounted for.
3075 * If the ops does not trace the current record function, skip it.
3076 * If the ops ignores the function via notrace filter, skip it.
3077 */
3078static inline bool
3079ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3080{
3081 /* If ops isn't enabled, ignore it */
3082 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3083 return false;
3084
3085 /* If ops traces all then it includes this function */
3086 if (ops_traces_mod(ops))
3087 return true;
3088
3089 /* The function must be in the filter */
3090 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3091 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3092 return false;
3093
3094 /* If in notrace hash, we ignore it too */
3095 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3096 return false;
3097
3098 return true;
3099}
3100
3101static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3102{
3103 struct ftrace_page *pg;
3104 struct dyn_ftrace *p;
3105 u64 start, stop;
3106 unsigned long update_cnt = 0;
3107 unsigned long rec_flags = 0;
3108 int i;
3109
3110 start = ftrace_now(raw_smp_processor_id());
3111
3112 /*
3113 * When a module is loaded, this function is called to convert
3114 * the calls to mcount in its text to nops, and also to create
3115 * an entry in the ftrace data. Now, if ftrace is activated
3116 * after this call, but before the module sets its text to
3117 * read-only, the modification of enabling ftrace can fail if
3118 * the read-only is done while ftrace is converting the calls.
3119 * To prevent this, the module's records are set as disabled
3120 * and will be enabled after the call to set the module's text
3121 * to read-only.
3122 */
3123 if (mod)
3124 rec_flags |= FTRACE_FL_DISABLED;
3125
3126 for (pg = new_pgs; pg; pg = pg->next) {
3127
3128 for (i = 0; i < pg->index; i++) {
3129
3130 /* If something went wrong, bail without enabling anything */
3131 if (unlikely(ftrace_disabled))
3132 return -1;
3133
3134 p = &pg->records[i];
3135 p->flags = rec_flags;
3136
3137 /*
3138 * Do the initial record conversion from mcount jump
3139 * to the NOP instructions.
3140 */
3141 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3142 !ftrace_nop_initialize(mod, p))
3143 break;
3144
3145 update_cnt++;
3146 }
3147 }
3148
3149 stop = ftrace_now(raw_smp_processor_id());
3150 ftrace_update_time = stop - start;
3151 ftrace_update_tot_cnt += update_cnt;
3152
3153 return 0;
3154}
3155
3156static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3157{
3158 int order;
3159 int pages;
3160 int cnt;
3161
3162 if (WARN_ON(!count))
3163 return -EINVAL;
3164
3165 /* We want to fill as much as possible, with no empty pages */
3166 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3167 order = fls(pages) - 1;
3168
3169 again:
3170 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3171
3172 if (!pg->records) {
3173 /* if we can't allocate this size, try something smaller */
3174 if (!order)
3175 return -ENOMEM;
3176 order >>= 1;
3177 goto again;
3178 }
3179
3180 ftrace_number_of_pages += 1 << order;
3181 ftrace_number_of_groups++;
3182
3183 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3184 pg->order = order;
3185
3186 if (cnt > count)
3187 cnt = count;
3188
3189 return cnt;
3190}
3191
3192static struct ftrace_page *
3193ftrace_allocate_pages(unsigned long num_to_init)
3194{
3195 struct ftrace_page *start_pg;
3196 struct ftrace_page *pg;
3197 int cnt;
3198
3199 if (!num_to_init)
3200 return NULL;
3201
3202 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3203 if (!pg)
3204 return NULL;
3205
3206 /*
3207 * Try to allocate as much as possible in one continues
3208 * location that fills in all of the space. We want to
3209 * waste as little space as possible.
3210 */
3211 for (;;) {
3212 cnt = ftrace_allocate_records(pg, num_to_init);
3213 if (cnt < 0)
3214 goto free_pages;
3215
3216 num_to_init -= cnt;
3217 if (!num_to_init)
3218 break;
3219
3220 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3221 if (!pg->next)
3222 goto free_pages;
3223
3224 pg = pg->next;
3225 }
3226
3227 return start_pg;
3228
3229 free_pages:
3230 pg = start_pg;
3231 while (pg) {
3232 if (pg->records) {
3233 free_pages((unsigned long)pg->records, pg->order);
3234 ftrace_number_of_pages -= 1 << pg->order;
3235 }
3236 start_pg = pg->next;
3237 kfree(pg);
3238 pg = start_pg;
3239 ftrace_number_of_groups--;
3240 }
3241 pr_info("ftrace: FAILED to allocate memory for functions\n");
3242 return NULL;
3243}
3244
3245#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3246
3247struct ftrace_iterator {
3248 loff_t pos;
3249 loff_t func_pos;
3250 loff_t mod_pos;
3251 struct ftrace_page *pg;
3252 struct dyn_ftrace *func;
3253 struct ftrace_func_probe *probe;
3254 struct ftrace_func_entry *probe_entry;
3255 struct trace_parser parser;
3256 struct ftrace_hash *hash;
3257 struct ftrace_ops *ops;
3258 struct trace_array *tr;
3259 struct list_head *mod_list;
3260 int pidx;
3261 int idx;
3262 unsigned flags;
3263};
3264
3265static void *
3266t_probe_next(struct seq_file *m, loff_t *pos)
3267{
3268 struct ftrace_iterator *iter = m->private;
3269 struct trace_array *tr = iter->ops->private;
3270 struct list_head *func_probes;
3271 struct ftrace_hash *hash;
3272 struct list_head *next;
3273 struct hlist_node *hnd = NULL;
3274 struct hlist_head *hhd;
3275 int size;
3276
3277 (*pos)++;
3278 iter->pos = *pos;
3279
3280 if (!tr)
3281 return NULL;
3282
3283 func_probes = &tr->func_probes;
3284 if (list_empty(func_probes))
3285 return NULL;
3286
3287 if (!iter->probe) {
3288 next = func_probes->next;
3289 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3290 }
3291
3292 if (iter->probe_entry)
3293 hnd = &iter->probe_entry->hlist;
3294
3295 hash = iter->probe->ops.func_hash->filter_hash;
3296
3297 /*
3298 * A probe being registered may temporarily have an empty hash
3299 * and it's at the end of the func_probes list.
3300 */
3301 if (!hash || hash == EMPTY_HASH)
3302 return NULL;
3303
3304 size = 1 << hash->size_bits;
3305
3306 retry:
3307 if (iter->pidx >= size) {
3308 if (iter->probe->list.next == func_probes)
3309 return NULL;
3310 next = iter->probe->list.next;
3311 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3312 hash = iter->probe->ops.func_hash->filter_hash;
3313 size = 1 << hash->size_bits;
3314 iter->pidx = 0;
3315 }
3316
3317 hhd = &hash->buckets[iter->pidx];
3318
3319 if (hlist_empty(hhd)) {
3320 iter->pidx++;
3321 hnd = NULL;
3322 goto retry;
3323 }
3324
3325 if (!hnd)
3326 hnd = hhd->first;
3327 else {
3328 hnd = hnd->next;
3329 if (!hnd) {
3330 iter->pidx++;
3331 goto retry;
3332 }
3333 }
3334
3335 if (WARN_ON_ONCE(!hnd))
3336 return NULL;
3337
3338 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3339
3340 return iter;
3341}
3342
3343static void *t_probe_start(struct seq_file *m, loff_t *pos)
3344{
3345 struct ftrace_iterator *iter = m->private;
3346 void *p = NULL;
3347 loff_t l;
3348
3349 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3350 return NULL;
3351
3352 if (iter->mod_pos > *pos)
3353 return NULL;
3354
3355 iter->probe = NULL;
3356 iter->probe_entry = NULL;
3357 iter->pidx = 0;
3358 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3359 p = t_probe_next(m, &l);
3360 if (!p)
3361 break;
3362 }
3363 if (!p)
3364 return NULL;
3365
3366 /* Only set this if we have an item */
3367 iter->flags |= FTRACE_ITER_PROBE;
3368
3369 return iter;
3370}
3371
3372static int
3373t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3374{
3375 struct ftrace_func_entry *probe_entry;
3376 struct ftrace_probe_ops *probe_ops;
3377 struct ftrace_func_probe *probe;
3378
3379 probe = iter->probe;
3380 probe_entry = iter->probe_entry;
3381
3382 if (WARN_ON_ONCE(!probe || !probe_entry))
3383 return -EIO;
3384
3385 probe_ops = probe->probe_ops;
3386
3387 if (probe_ops->print)
3388 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3389
3390 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3391 (void *)probe_ops->func);
3392
3393 return 0;
3394}
3395
3396static void *
3397t_mod_next(struct seq_file *m, loff_t *pos)
3398{
3399 struct ftrace_iterator *iter = m->private;
3400 struct trace_array *tr = iter->tr;
3401
3402 (*pos)++;
3403 iter->pos = *pos;
3404
3405 iter->mod_list = iter->mod_list->next;
3406
3407 if (iter->mod_list == &tr->mod_trace ||
3408 iter->mod_list == &tr->mod_notrace) {
3409 iter->flags &= ~FTRACE_ITER_MOD;
3410 return NULL;
3411 }
3412
3413 iter->mod_pos = *pos;
3414
3415 return iter;
3416}
3417
3418static void *t_mod_start(struct seq_file *m, loff_t *pos)
3419{
3420 struct ftrace_iterator *iter = m->private;
3421 void *p = NULL;
3422 loff_t l;
3423
3424 if (iter->func_pos > *pos)
3425 return NULL;
3426
3427 iter->mod_pos = iter->func_pos;
3428
3429 /* probes are only available if tr is set */
3430 if (!iter->tr)
3431 return NULL;
3432
3433 for (l = 0; l <= (*pos - iter->func_pos); ) {
3434 p = t_mod_next(m, &l);
3435 if (!p)
3436 break;
3437 }
3438 if (!p) {
3439 iter->flags &= ~FTRACE_ITER_MOD;
3440 return t_probe_start(m, pos);
3441 }
3442
3443 /* Only set this if we have an item */
3444 iter->flags |= FTRACE_ITER_MOD;
3445
3446 return iter;
3447}
3448
3449static int
3450t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3451{
3452 struct ftrace_mod_load *ftrace_mod;
3453 struct trace_array *tr = iter->tr;
3454
3455 if (WARN_ON_ONCE(!iter->mod_list) ||
3456 iter->mod_list == &tr->mod_trace ||
3457 iter->mod_list == &tr->mod_notrace)
3458 return -EIO;
3459
3460 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3461
3462 if (ftrace_mod->func)
3463 seq_printf(m, "%s", ftrace_mod->func);
3464 else
3465 seq_putc(m, '*');
3466
3467 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3468
3469 return 0;
3470}
3471
3472static void *
3473t_func_next(struct seq_file *m, loff_t *pos)
3474{
3475 struct ftrace_iterator *iter = m->private;
3476 struct dyn_ftrace *rec = NULL;
3477
3478 (*pos)++;
3479
3480 retry:
3481 if (iter->idx >= iter->pg->index) {
3482 if (iter->pg->next) {
3483 iter->pg = iter->pg->next;
3484 iter->idx = 0;
3485 goto retry;
3486 }
3487 } else {
3488 rec = &iter->pg->records[iter->idx++];
3489 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3490 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3491
3492 ((iter->flags & FTRACE_ITER_ENABLED) &&
3493 !(rec->flags & FTRACE_FL_ENABLED))) {
3494
3495 rec = NULL;
3496 goto retry;
3497 }
3498 }
3499
3500 if (!rec)
3501 return NULL;
3502
3503 iter->pos = iter->func_pos = *pos;
3504 iter->func = rec;
3505
3506 return iter;
3507}
3508
3509static void *
3510t_next(struct seq_file *m, void *v, loff_t *pos)
3511{
3512 struct ftrace_iterator *iter = m->private;
3513 loff_t l = *pos; /* t_probe_start() must use original pos */
3514 void *ret;
3515
3516 if (unlikely(ftrace_disabled))
3517 return NULL;
3518
3519 if (iter->flags & FTRACE_ITER_PROBE)
3520 return t_probe_next(m, pos);
3521
3522 if (iter->flags & FTRACE_ITER_MOD)
3523 return t_mod_next(m, pos);
3524
3525 if (iter->flags & FTRACE_ITER_PRINTALL) {
3526 /* next must increment pos, and t_probe_start does not */
3527 (*pos)++;
3528 return t_mod_start(m, &l);
3529 }
3530
3531 ret = t_func_next(m, pos);
3532
3533 if (!ret)
3534 return t_mod_start(m, &l);
3535
3536 return ret;
3537}
3538
3539static void reset_iter_read(struct ftrace_iterator *iter)
3540{
3541 iter->pos = 0;
3542 iter->func_pos = 0;
3543 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3544}
3545
3546static void *t_start(struct seq_file *m, loff_t *pos)
3547{
3548 struct ftrace_iterator *iter = m->private;
3549 void *p = NULL;
3550 loff_t l;
3551
3552 mutex_lock(&ftrace_lock);
3553
3554 if (unlikely(ftrace_disabled))
3555 return NULL;
3556
3557 /*
3558 * If an lseek was done, then reset and start from beginning.
3559 */
3560 if (*pos < iter->pos)
3561 reset_iter_read(iter);
3562
3563 /*
3564 * For set_ftrace_filter reading, if we have the filter
3565 * off, we can short cut and just print out that all
3566 * functions are enabled.
3567 */
3568 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3569 ftrace_hash_empty(iter->hash)) {
3570 iter->func_pos = 1; /* Account for the message */
3571 if (*pos > 0)
3572 return t_mod_start(m, pos);
3573 iter->flags |= FTRACE_ITER_PRINTALL;
3574 /* reset in case of seek/pread */
3575 iter->flags &= ~FTRACE_ITER_PROBE;
3576 return iter;
3577 }
3578
3579 if (iter->flags & FTRACE_ITER_MOD)
3580 return t_mod_start(m, pos);
3581
3582 /*
3583 * Unfortunately, we need to restart at ftrace_pages_start
3584 * every time we let go of the ftrace_mutex. This is because
3585 * those pointers can change without the lock.
3586 */
3587 iter->pg = ftrace_pages_start;
3588 iter->idx = 0;
3589 for (l = 0; l <= *pos; ) {
3590 p = t_func_next(m, &l);
3591 if (!p)
3592 break;
3593 }
3594
3595 if (!p)
3596 return t_mod_start(m, pos);
3597
3598 return iter;
3599}
3600
3601static void t_stop(struct seq_file *m, void *p)
3602{
3603 mutex_unlock(&ftrace_lock);
3604}
3605
3606void * __weak
3607arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3608{
3609 return NULL;
3610}
3611
3612static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3613 struct dyn_ftrace *rec)
3614{
3615 void *ptr;
3616
3617 ptr = arch_ftrace_trampoline_func(ops, rec);
3618 if (ptr)
3619 seq_printf(m, " ->%pS", ptr);
3620}
3621
3622static int t_show(struct seq_file *m, void *v)
3623{
3624 struct ftrace_iterator *iter = m->private;
3625 struct dyn_ftrace *rec;
3626
3627 if (iter->flags & FTRACE_ITER_PROBE)
3628 return t_probe_show(m, iter);
3629
3630 if (iter->flags & FTRACE_ITER_MOD)
3631 return t_mod_show(m, iter);
3632
3633 if (iter->flags & FTRACE_ITER_PRINTALL) {
3634 if (iter->flags & FTRACE_ITER_NOTRACE)
3635 seq_puts(m, "#### no functions disabled ####\n");
3636 else
3637 seq_puts(m, "#### all functions enabled ####\n");
3638 return 0;
3639 }
3640
3641 rec = iter->func;
3642
3643 if (!rec)
3644 return 0;
3645
3646 seq_printf(m, "%ps", (void *)rec->ip);
3647 if (iter->flags & FTRACE_ITER_ENABLED) {
3648 struct ftrace_ops *ops;
3649
3650 seq_printf(m, " (%ld)%s%s%s",
3651 ftrace_rec_count(rec),
3652 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3653 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3654 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3655 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3656 ops = ftrace_find_tramp_ops_any(rec);
3657 if (ops) {
3658 do {
3659 seq_printf(m, "\ttramp: %pS (%pS)",
3660 (void *)ops->trampoline,
3661 (void *)ops->func);
3662 add_trampoline_func(m, ops, rec);
3663 ops = ftrace_find_tramp_ops_next(rec, ops);
3664 } while (ops);
3665 } else
3666 seq_puts(m, "\ttramp: ERROR!");
3667 } else {
3668 add_trampoline_func(m, NULL, rec);
3669 }
3670 if (rec->flags & FTRACE_FL_DIRECT) {
3671 unsigned long direct;
3672
3673 direct = ftrace_find_rec_direct(rec->ip);
3674 if (direct)
3675 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3676 }
3677 }
3678
3679 seq_putc(m, '\n');
3680
3681 return 0;
3682}
3683
3684static const struct seq_operations show_ftrace_seq_ops = {
3685 .start = t_start,
3686 .next = t_next,
3687 .stop = t_stop,
3688 .show = t_show,
3689};
3690
3691static int
3692ftrace_avail_open(struct inode *inode, struct file *file)
3693{
3694 struct ftrace_iterator *iter;
3695 int ret;
3696
3697 ret = security_locked_down(LOCKDOWN_TRACEFS);
3698 if (ret)
3699 return ret;
3700
3701 if (unlikely(ftrace_disabled))
3702 return -ENODEV;
3703
3704 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3705 if (!iter)
3706 return -ENOMEM;
3707
3708 iter->pg = ftrace_pages_start;
3709 iter->ops = &global_ops;
3710
3711 return 0;
3712}
3713
3714static int
3715ftrace_enabled_open(struct inode *inode, struct file *file)
3716{
3717 struct ftrace_iterator *iter;
3718
3719 /*
3720 * This shows us what functions are currently being
3721 * traced and by what. Not sure if we want lockdown
3722 * to hide such critical information for an admin.
3723 * Although, perhaps it can show information we don't
3724 * want people to see, but if something is tracing
3725 * something, we probably want to know about it.
3726 */
3727
3728 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3729 if (!iter)
3730 return -ENOMEM;
3731
3732 iter->pg = ftrace_pages_start;
3733 iter->flags = FTRACE_ITER_ENABLED;
3734 iter->ops = &global_ops;
3735
3736 return 0;
3737}
3738
3739/**
3740 * ftrace_regex_open - initialize function tracer filter files
3741 * @ops: The ftrace_ops that hold the hash filters
3742 * @flag: The type of filter to process
3743 * @inode: The inode, usually passed in to your open routine
3744 * @file: The file, usually passed in to your open routine
3745 *
3746 * ftrace_regex_open() initializes the filter files for the
3747 * @ops. Depending on @flag it may process the filter hash or
3748 * the notrace hash of @ops. With this called from the open
3749 * routine, you can use ftrace_filter_write() for the write
3750 * routine if @flag has FTRACE_ITER_FILTER set, or
3751 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3752 * tracing_lseek() should be used as the lseek routine, and
3753 * release must call ftrace_regex_release().
3754 */
3755int
3756ftrace_regex_open(struct ftrace_ops *ops, int flag,
3757 struct inode *inode, struct file *file)
3758{
3759 struct ftrace_iterator *iter;
3760 struct ftrace_hash *hash;
3761 struct list_head *mod_head;
3762 struct trace_array *tr = ops->private;
3763 int ret = -ENOMEM;
3764
3765 ftrace_ops_init(ops);
3766
3767 if (unlikely(ftrace_disabled))
3768 return -ENODEV;
3769
3770 if (tracing_check_open_get_tr(tr))
3771 return -ENODEV;
3772
3773 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3774 if (!iter)
3775 goto out;
3776
3777 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3778 goto out;
3779
3780 iter->ops = ops;
3781 iter->flags = flag;
3782 iter->tr = tr;
3783
3784 mutex_lock(&ops->func_hash->regex_lock);
3785
3786 if (flag & FTRACE_ITER_NOTRACE) {
3787 hash = ops->func_hash->notrace_hash;
3788 mod_head = tr ? &tr->mod_notrace : NULL;
3789 } else {
3790 hash = ops->func_hash->filter_hash;
3791 mod_head = tr ? &tr->mod_trace : NULL;
3792 }
3793
3794 iter->mod_list = mod_head;
3795
3796 if (file->f_mode & FMODE_WRITE) {
3797 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3798
3799 if (file->f_flags & O_TRUNC) {
3800 iter->hash = alloc_ftrace_hash(size_bits);
3801 clear_ftrace_mod_list(mod_head);
3802 } else {
3803 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3804 }
3805
3806 if (!iter->hash) {
3807 trace_parser_put(&iter->parser);
3808 goto out_unlock;
3809 }
3810 } else
3811 iter->hash = hash;
3812
3813 ret = 0;
3814
3815 if (file->f_mode & FMODE_READ) {
3816 iter->pg = ftrace_pages_start;
3817
3818 ret = seq_open(file, &show_ftrace_seq_ops);
3819 if (!ret) {
3820 struct seq_file *m = file->private_data;
3821 m->private = iter;
3822 } else {
3823 /* Failed */
3824 free_ftrace_hash(iter->hash);
3825 trace_parser_put(&iter->parser);
3826 }
3827 } else
3828 file->private_data = iter;
3829
3830 out_unlock:
3831 mutex_unlock(&ops->func_hash->regex_lock);
3832
3833 out:
3834 if (ret) {
3835 kfree(iter);
3836 if (tr)
3837 trace_array_put(tr);
3838 }
3839
3840 return ret;
3841}
3842
3843static int
3844ftrace_filter_open(struct inode *inode, struct file *file)
3845{
3846 struct ftrace_ops *ops = inode->i_private;
3847
3848 /* Checks for tracefs lockdown */
3849 return ftrace_regex_open(ops,
3850 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3851 inode, file);
3852}
3853
3854static int
3855ftrace_notrace_open(struct inode *inode, struct file *file)
3856{
3857 struct ftrace_ops *ops = inode->i_private;
3858
3859 /* Checks for tracefs lockdown */
3860 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3861 inode, file);
3862}
3863
3864/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3865struct ftrace_glob {
3866 char *search;
3867 unsigned len;
3868 int type;
3869};
3870
3871/*
3872 * If symbols in an architecture don't correspond exactly to the user-visible
3873 * name of what they represent, it is possible to define this function to
3874 * perform the necessary adjustments.
3875*/
3876char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3877{
3878 return str;
3879}
3880
3881static int ftrace_match(char *str, struct ftrace_glob *g)
3882{
3883 int matched = 0;
3884 int slen;
3885
3886 str = arch_ftrace_match_adjust(str, g->search);
3887
3888 switch (g->type) {
3889 case MATCH_FULL:
3890 if (strcmp(str, g->search) == 0)
3891 matched = 1;
3892 break;
3893 case MATCH_FRONT_ONLY:
3894 if (strncmp(str, g->search, g->len) == 0)
3895 matched = 1;
3896 break;
3897 case MATCH_MIDDLE_ONLY:
3898 if (strstr(str, g->search))
3899 matched = 1;
3900 break;
3901 case MATCH_END_ONLY:
3902 slen = strlen(str);
3903 if (slen >= g->len &&
3904 memcmp(str + slen - g->len, g->search, g->len) == 0)
3905 matched = 1;
3906 break;
3907 case MATCH_GLOB:
3908 if (glob_match(g->search, str))
3909 matched = 1;
3910 break;
3911 }
3912
3913 return matched;
3914}
3915
3916static int
3917enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3918{
3919 struct ftrace_func_entry *entry;
3920 int ret = 0;
3921
3922 entry = ftrace_lookup_ip(hash, rec->ip);
3923 if (clear_filter) {
3924 /* Do nothing if it doesn't exist */
3925 if (!entry)
3926 return 0;
3927
3928 free_hash_entry(hash, entry);
3929 } else {
3930 /* Do nothing if it exists */
3931 if (entry)
3932 return 0;
3933
3934 ret = add_hash_entry(hash, rec->ip);
3935 }
3936 return ret;
3937}
3938
3939static int
3940add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3941 int clear_filter)
3942{
3943 long index = simple_strtoul(func_g->search, NULL, 0);
3944 struct ftrace_page *pg;
3945 struct dyn_ftrace *rec;
3946
3947 /* The index starts at 1 */
3948 if (--index < 0)
3949 return 0;
3950
3951 do_for_each_ftrace_rec(pg, rec) {
3952 if (pg->index <= index) {
3953 index -= pg->index;
3954 /* this is a double loop, break goes to the next page */
3955 break;
3956 }
3957 rec = &pg->records[index];
3958 enter_record(hash, rec, clear_filter);
3959 return 1;
3960 } while_for_each_ftrace_rec();
3961 return 0;
3962}
3963
3964static int
3965ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3966 struct ftrace_glob *mod_g, int exclude_mod)
3967{
3968 char str[KSYM_SYMBOL_LEN];
3969 char *modname;
3970
3971 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3972
3973 if (mod_g) {
3974 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3975
3976 /* blank module name to match all modules */
3977 if (!mod_g->len) {
3978 /* blank module globbing: modname xor exclude_mod */
3979 if (!exclude_mod != !modname)
3980 goto func_match;
3981 return 0;
3982 }
3983
3984 /*
3985 * exclude_mod is set to trace everything but the given
3986 * module. If it is set and the module matches, then
3987 * return 0. If it is not set, and the module doesn't match
3988 * also return 0. Otherwise, check the function to see if
3989 * that matches.
3990 */
3991 if (!mod_matches == !exclude_mod)
3992 return 0;
3993func_match:
3994 /* blank search means to match all funcs in the mod */
3995 if (!func_g->len)
3996 return 1;
3997 }
3998
3999 return ftrace_match(str, func_g);
4000}
4001
4002static int
4003match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4004{
4005 struct ftrace_page *pg;
4006 struct dyn_ftrace *rec;
4007 struct ftrace_glob func_g = { .type = MATCH_FULL };
4008 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4009 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4010 int exclude_mod = 0;
4011 int found = 0;
4012 int ret;
4013 int clear_filter = 0;
4014
4015 if (func) {
4016 func_g.type = filter_parse_regex(func, len, &func_g.search,
4017 &clear_filter);
4018 func_g.len = strlen(func_g.search);
4019 }
4020
4021 if (mod) {
4022 mod_g.type = filter_parse_regex(mod, strlen(mod),
4023 &mod_g.search, &exclude_mod);
4024 mod_g.len = strlen(mod_g.search);
4025 }
4026
4027 mutex_lock(&ftrace_lock);
4028
4029 if (unlikely(ftrace_disabled))
4030 goto out_unlock;
4031
4032 if (func_g.type == MATCH_INDEX) {
4033 found = add_rec_by_index(hash, &func_g, clear_filter);
4034 goto out_unlock;
4035 }
4036
4037 do_for_each_ftrace_rec(pg, rec) {
4038
4039 if (rec->flags & FTRACE_FL_DISABLED)
4040 continue;
4041
4042 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4043 ret = enter_record(hash, rec, clear_filter);
4044 if (ret < 0) {
4045 found = ret;
4046 goto out_unlock;
4047 }
4048 found = 1;
4049 }
4050 } while_for_each_ftrace_rec();
4051 out_unlock:
4052 mutex_unlock(&ftrace_lock);
4053
4054 return found;
4055}
4056
4057static int
4058ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4059{
4060 return match_records(hash, buff, len, NULL);
4061}
4062
4063static void ftrace_ops_update_code(struct ftrace_ops *ops,
4064 struct ftrace_ops_hash *old_hash)
4065{
4066 struct ftrace_ops *op;
4067
4068 if (!ftrace_enabled)
4069 return;
4070
4071 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4072 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4073 return;
4074 }
4075
4076 /*
4077 * If this is the shared global_ops filter, then we need to
4078 * check if there is another ops that shares it, is enabled.
4079 * If so, we still need to run the modify code.
4080 */
4081 if (ops->func_hash != &global_ops.local_hash)
4082 return;
4083
4084 do_for_each_ftrace_op(op, ftrace_ops_list) {
4085 if (op->func_hash == &global_ops.local_hash &&
4086 op->flags & FTRACE_OPS_FL_ENABLED) {
4087 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4088 /* Only need to do this once */
4089 return;
4090 }
4091 } while_for_each_ftrace_op(op);
4092}
4093
4094static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4095 struct ftrace_hash **orig_hash,
4096 struct ftrace_hash *hash,
4097 int enable)
4098{
4099 struct ftrace_ops_hash old_hash_ops;
4100 struct ftrace_hash *old_hash;
4101 int ret;
4102
4103 old_hash = *orig_hash;
4104 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4105 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4106 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4107 if (!ret) {
4108 ftrace_ops_update_code(ops, &old_hash_ops);
4109 free_ftrace_hash_rcu(old_hash);
4110 }
4111 return ret;
4112}
4113
4114static bool module_exists(const char *module)
4115{
4116 /* All modules have the symbol __this_module */
4117 static const char this_mod[] = "__this_module";
4118 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4119 unsigned long val;
4120 int n;
4121
4122 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4123
4124 if (n > sizeof(modname) - 1)
4125 return false;
4126
4127 val = module_kallsyms_lookup_name(modname);
4128 return val != 0;
4129}
4130
4131static int cache_mod(struct trace_array *tr,
4132 const char *func, char *module, int enable)
4133{
4134 struct ftrace_mod_load *ftrace_mod, *n;
4135 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4136 int ret;
4137
4138 mutex_lock(&ftrace_lock);
4139
4140 /* We do not cache inverse filters */
4141 if (func[0] == '!') {
4142 func++;
4143 ret = -EINVAL;
4144
4145 /* Look to remove this hash */
4146 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4147 if (strcmp(ftrace_mod->module, module) != 0)
4148 continue;
4149
4150 /* no func matches all */
4151 if (strcmp(func, "*") == 0 ||
4152 (ftrace_mod->func &&
4153 strcmp(ftrace_mod->func, func) == 0)) {
4154 ret = 0;
4155 free_ftrace_mod(ftrace_mod);
4156 continue;
4157 }
4158 }
4159 goto out;
4160 }
4161
4162 ret = -EINVAL;
4163 /* We only care about modules that have not been loaded yet */
4164 if (module_exists(module))
4165 goto out;
4166
4167 /* Save this string off, and execute it when the module is loaded */
4168 ret = ftrace_add_mod(tr, func, module, enable);
4169 out:
4170 mutex_unlock(&ftrace_lock);
4171
4172 return ret;
4173}
4174
4175static int
4176ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4177 int reset, int enable);
4178
4179#ifdef CONFIG_MODULES
4180static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4181 char *mod, bool enable)
4182{
4183 struct ftrace_mod_load *ftrace_mod, *n;
4184 struct ftrace_hash **orig_hash, *new_hash;
4185 LIST_HEAD(process_mods);
4186 char *func;
4187
4188 mutex_lock(&ops->func_hash->regex_lock);
4189
4190 if (enable)
4191 orig_hash = &ops->func_hash->filter_hash;
4192 else
4193 orig_hash = &ops->func_hash->notrace_hash;
4194
4195 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4196 *orig_hash);
4197 if (!new_hash)
4198 goto out; /* warn? */
4199
4200 mutex_lock(&ftrace_lock);
4201
4202 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4203
4204 if (strcmp(ftrace_mod->module, mod) != 0)
4205 continue;
4206
4207 if (ftrace_mod->func)
4208 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4209 else
4210 func = kstrdup("*", GFP_KERNEL);
4211
4212 if (!func) /* warn? */
4213 continue;
4214
4215 list_move(&ftrace_mod->list, &process_mods);
4216
4217 /* Use the newly allocated func, as it may be "*" */
4218 kfree(ftrace_mod->func);
4219 ftrace_mod->func = func;
4220 }
4221
4222 mutex_unlock(&ftrace_lock);
4223
4224 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4225
4226 func = ftrace_mod->func;
4227
4228 /* Grabs ftrace_lock, which is why we have this extra step */
4229 match_records(new_hash, func, strlen(func), mod);
4230 free_ftrace_mod(ftrace_mod);
4231 }
4232
4233 if (enable && list_empty(head))
4234 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4235
4236 mutex_lock(&ftrace_lock);
4237
4238 ftrace_hash_move_and_update_ops(ops, orig_hash,
4239 new_hash, enable);
4240 mutex_unlock(&ftrace_lock);
4241
4242 out:
4243 mutex_unlock(&ops->func_hash->regex_lock);
4244
4245 free_ftrace_hash(new_hash);
4246}
4247
4248static void process_cached_mods(const char *mod_name)
4249{
4250 struct trace_array *tr;
4251 char *mod;
4252
4253 mod = kstrdup(mod_name, GFP_KERNEL);
4254 if (!mod)
4255 return;
4256
4257 mutex_lock(&trace_types_lock);
4258 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4259 if (!list_empty(&tr->mod_trace))
4260 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4261 if (!list_empty(&tr->mod_notrace))
4262 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4263 }
4264 mutex_unlock(&trace_types_lock);
4265
4266 kfree(mod);
4267}
4268#endif
4269
4270/*
4271 * We register the module command as a template to show others how
4272 * to register the a command as well.
4273 */
4274
4275static int
4276ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4277 char *func_orig, char *cmd, char *module, int enable)
4278{
4279 char *func;
4280 int ret;
4281
4282 /* match_records() modifies func, and we need the original */
4283 func = kstrdup(func_orig, GFP_KERNEL);
4284 if (!func)
4285 return -ENOMEM;
4286
4287 /*
4288 * cmd == 'mod' because we only registered this func
4289 * for the 'mod' ftrace_func_command.
4290 * But if you register one func with multiple commands,
4291 * you can tell which command was used by the cmd
4292 * parameter.
4293 */
4294 ret = match_records(hash, func, strlen(func), module);
4295 kfree(func);
4296
4297 if (!ret)
4298 return cache_mod(tr, func_orig, module, enable);
4299 if (ret < 0)
4300 return ret;
4301 return 0;
4302}
4303
4304static struct ftrace_func_command ftrace_mod_cmd = {
4305 .name = "mod",
4306 .func = ftrace_mod_callback,
4307};
4308
4309static int __init ftrace_mod_cmd_init(void)
4310{
4311 return register_ftrace_command(&ftrace_mod_cmd);
4312}
4313core_initcall(ftrace_mod_cmd_init);
4314
4315static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4316 struct ftrace_ops *op, struct ftrace_regs *fregs)
4317{
4318 struct ftrace_probe_ops *probe_ops;
4319 struct ftrace_func_probe *probe;
4320
4321 probe = container_of(op, struct ftrace_func_probe, ops);
4322 probe_ops = probe->probe_ops;
4323
4324 /*
4325 * Disable preemption for these calls to prevent a RCU grace
4326 * period. This syncs the hash iteration and freeing of items
4327 * on the hash. rcu_read_lock is too dangerous here.
4328 */
4329 preempt_disable_notrace();
4330 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4331 preempt_enable_notrace();
4332}
4333
4334struct ftrace_func_map {
4335 struct ftrace_func_entry entry;
4336 void *data;
4337};
4338
4339struct ftrace_func_mapper {
4340 struct ftrace_hash hash;
4341};
4342
4343/**
4344 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4345 *
4346 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4347 */
4348struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4349{
4350 struct ftrace_hash *hash;
4351
4352 /*
4353 * The mapper is simply a ftrace_hash, but since the entries
4354 * in the hash are not ftrace_func_entry type, we define it
4355 * as a separate structure.
4356 */
4357 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4358 return (struct ftrace_func_mapper *)hash;
4359}
4360
4361/**
4362 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4363 * @mapper: The mapper that has the ip maps
4364 * @ip: the instruction pointer to find the data for
4365 *
4366 * Returns the data mapped to @ip if found otherwise NULL. The return
4367 * is actually the address of the mapper data pointer. The address is
4368 * returned for use cases where the data is no bigger than a long, and
4369 * the user can use the data pointer as its data instead of having to
4370 * allocate more memory for the reference.
4371 */
4372void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4373 unsigned long ip)
4374{
4375 struct ftrace_func_entry *entry;
4376 struct ftrace_func_map *map;
4377
4378 entry = ftrace_lookup_ip(&mapper->hash, ip);
4379 if (!entry)
4380 return NULL;
4381
4382 map = (struct ftrace_func_map *)entry;
4383 return &map->data;
4384}
4385
4386/**
4387 * ftrace_func_mapper_add_ip - Map some data to an ip
4388 * @mapper: The mapper that has the ip maps
4389 * @ip: The instruction pointer address to map @data to
4390 * @data: The data to map to @ip
4391 *
4392 * Returns 0 on success otherwise an error.
4393 */
4394int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4395 unsigned long ip, void *data)
4396{
4397 struct ftrace_func_entry *entry;
4398 struct ftrace_func_map *map;
4399
4400 entry = ftrace_lookup_ip(&mapper->hash, ip);
4401 if (entry)
4402 return -EBUSY;
4403
4404 map = kmalloc(sizeof(*map), GFP_KERNEL);
4405 if (!map)
4406 return -ENOMEM;
4407
4408 map->entry.ip = ip;
4409 map->data = data;
4410
4411 __add_hash_entry(&mapper->hash, &map->entry);
4412
4413 return 0;
4414}
4415
4416/**
4417 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4418 * @mapper: The mapper that has the ip maps
4419 * @ip: The instruction pointer address to remove the data from
4420 *
4421 * Returns the data if it is found, otherwise NULL.
4422 * Note, if the data pointer is used as the data itself, (see
4423 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4424 * if the data pointer was set to zero.
4425 */
4426void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4427 unsigned long ip)
4428{
4429 struct ftrace_func_entry *entry;
4430 struct ftrace_func_map *map;
4431 void *data;
4432
4433 entry = ftrace_lookup_ip(&mapper->hash, ip);
4434 if (!entry)
4435 return NULL;
4436
4437 map = (struct ftrace_func_map *)entry;
4438 data = map->data;
4439
4440 remove_hash_entry(&mapper->hash, entry);
4441 kfree(entry);
4442
4443 return data;
4444}
4445
4446/**
4447 * free_ftrace_func_mapper - free a mapping of ips and data
4448 * @mapper: The mapper that has the ip maps
4449 * @free_func: A function to be called on each data item.
4450 *
4451 * This is used to free the function mapper. The @free_func is optional
4452 * and can be used if the data needs to be freed as well.
4453 */
4454void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4455 ftrace_mapper_func free_func)
4456{
4457 struct ftrace_func_entry *entry;
4458 struct ftrace_func_map *map;
4459 struct hlist_head *hhd;
4460 int size, i;
4461
4462 if (!mapper)
4463 return;
4464
4465 if (free_func && mapper->hash.count) {
4466 size = 1 << mapper->hash.size_bits;
4467 for (i = 0; i < size; i++) {
4468 hhd = &mapper->hash.buckets[i];
4469 hlist_for_each_entry(entry, hhd, hlist) {
4470 map = (struct ftrace_func_map *)entry;
4471 free_func(map);
4472 }
4473 }
4474 }
4475 free_ftrace_hash(&mapper->hash);
4476}
4477
4478static void release_probe(struct ftrace_func_probe *probe)
4479{
4480 struct ftrace_probe_ops *probe_ops;
4481
4482 mutex_lock(&ftrace_lock);
4483
4484 WARN_ON(probe->ref <= 0);
4485
4486 /* Subtract the ref that was used to protect this instance */
4487 probe->ref--;
4488
4489 if (!probe->ref) {
4490 probe_ops = probe->probe_ops;
4491 /*
4492 * Sending zero as ip tells probe_ops to free
4493 * the probe->data itself
4494 */
4495 if (probe_ops->free)
4496 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4497 list_del(&probe->list);
4498 kfree(probe);
4499 }
4500 mutex_unlock(&ftrace_lock);
4501}
4502
4503static void acquire_probe_locked(struct ftrace_func_probe *probe)
4504{
4505 /*
4506 * Add one ref to keep it from being freed when releasing the
4507 * ftrace_lock mutex.
4508 */
4509 probe->ref++;
4510}
4511
4512int
4513register_ftrace_function_probe(char *glob, struct trace_array *tr,
4514 struct ftrace_probe_ops *probe_ops,
4515 void *data)
4516{
4517 struct ftrace_func_entry *entry;
4518 struct ftrace_func_probe *probe;
4519 struct ftrace_hash **orig_hash;
4520 struct ftrace_hash *old_hash;
4521 struct ftrace_hash *hash;
4522 int count = 0;
4523 int size;
4524 int ret;
4525 int i;
4526
4527 if (WARN_ON(!tr))
4528 return -EINVAL;
4529
4530 /* We do not support '!' for function probes */
4531 if (WARN_ON(glob[0] == '!'))
4532 return -EINVAL;
4533
4534
4535 mutex_lock(&ftrace_lock);
4536 /* Check if the probe_ops is already registered */
4537 list_for_each_entry(probe, &tr->func_probes, list) {
4538 if (probe->probe_ops == probe_ops)
4539 break;
4540 }
4541 if (&probe->list == &tr->func_probes) {
4542 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4543 if (!probe) {
4544 mutex_unlock(&ftrace_lock);
4545 return -ENOMEM;
4546 }
4547 probe->probe_ops = probe_ops;
4548 probe->ops.func = function_trace_probe_call;
4549 probe->tr = tr;
4550 ftrace_ops_init(&probe->ops);
4551 list_add(&probe->list, &tr->func_probes);
4552 }
4553
4554 acquire_probe_locked(probe);
4555
4556 mutex_unlock(&ftrace_lock);
4557
4558 /*
4559 * Note, there's a small window here that the func_hash->filter_hash
4560 * may be NULL or empty. Need to be careful when reading the loop.
4561 */
4562 mutex_lock(&probe->ops.func_hash->regex_lock);
4563
4564 orig_hash = &probe->ops.func_hash->filter_hash;
4565 old_hash = *orig_hash;
4566 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4567
4568 if (!hash) {
4569 ret = -ENOMEM;
4570 goto out;
4571 }
4572
4573 ret = ftrace_match_records(hash, glob, strlen(glob));
4574
4575 /* Nothing found? */
4576 if (!ret)
4577 ret = -EINVAL;
4578
4579 if (ret < 0)
4580 goto out;
4581
4582 size = 1 << hash->size_bits;
4583 for (i = 0; i < size; i++) {
4584 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4585 if (ftrace_lookup_ip(old_hash, entry->ip))
4586 continue;
4587 /*
4588 * The caller might want to do something special
4589 * for each function we find. We call the callback
4590 * to give the caller an opportunity to do so.
4591 */
4592 if (probe_ops->init) {
4593 ret = probe_ops->init(probe_ops, tr,
4594 entry->ip, data,
4595 &probe->data);
4596 if (ret < 0) {
4597 if (probe_ops->free && count)
4598 probe_ops->free(probe_ops, tr,
4599 0, probe->data);
4600 probe->data = NULL;
4601 goto out;
4602 }
4603 }
4604 count++;
4605 }
4606 }
4607
4608 mutex_lock(&ftrace_lock);
4609
4610 if (!count) {
4611 /* Nothing was added? */
4612 ret = -EINVAL;
4613 goto out_unlock;
4614 }
4615
4616 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4617 hash, 1);
4618 if (ret < 0)
4619 goto err_unlock;
4620
4621 /* One ref for each new function traced */
4622 probe->ref += count;
4623
4624 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4625 ret = ftrace_startup(&probe->ops, 0);
4626
4627 out_unlock:
4628 mutex_unlock(&ftrace_lock);
4629
4630 if (!ret)
4631 ret = count;
4632 out:
4633 mutex_unlock(&probe->ops.func_hash->regex_lock);
4634 free_ftrace_hash(hash);
4635
4636 release_probe(probe);
4637
4638 return ret;
4639
4640 err_unlock:
4641 if (!probe_ops->free || !count)
4642 goto out_unlock;
4643
4644 /* Failed to do the move, need to call the free functions */
4645 for (i = 0; i < size; i++) {
4646 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4647 if (ftrace_lookup_ip(old_hash, entry->ip))
4648 continue;
4649 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4650 }
4651 }
4652 goto out_unlock;
4653}
4654
4655int
4656unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4657 struct ftrace_probe_ops *probe_ops)
4658{
4659 struct ftrace_ops_hash old_hash_ops;
4660 struct ftrace_func_entry *entry;
4661 struct ftrace_func_probe *probe;
4662 struct ftrace_glob func_g;
4663 struct ftrace_hash **orig_hash;
4664 struct ftrace_hash *old_hash;
4665 struct ftrace_hash *hash = NULL;
4666 struct hlist_node *tmp;
4667 struct hlist_head hhd;
4668 char str[KSYM_SYMBOL_LEN];
4669 int count = 0;
4670 int i, ret = -ENODEV;
4671 int size;
4672
4673 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4674 func_g.search = NULL;
4675 else {
4676 int not;
4677
4678 func_g.type = filter_parse_regex(glob, strlen(glob),
4679 &func_g.search, ¬);
4680 func_g.len = strlen(func_g.search);
4681
4682 /* we do not support '!' for function probes */
4683 if (WARN_ON(not))
4684 return -EINVAL;
4685 }
4686
4687 mutex_lock(&ftrace_lock);
4688 /* Check if the probe_ops is already registered */
4689 list_for_each_entry(probe, &tr->func_probes, list) {
4690 if (probe->probe_ops == probe_ops)
4691 break;
4692 }
4693 if (&probe->list == &tr->func_probes)
4694 goto err_unlock_ftrace;
4695
4696 ret = -EINVAL;
4697 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4698 goto err_unlock_ftrace;
4699
4700 acquire_probe_locked(probe);
4701
4702 mutex_unlock(&ftrace_lock);
4703
4704 mutex_lock(&probe->ops.func_hash->regex_lock);
4705
4706 orig_hash = &probe->ops.func_hash->filter_hash;
4707 old_hash = *orig_hash;
4708
4709 if (ftrace_hash_empty(old_hash))
4710 goto out_unlock;
4711
4712 old_hash_ops.filter_hash = old_hash;
4713 /* Probes only have filters */
4714 old_hash_ops.notrace_hash = NULL;
4715
4716 ret = -ENOMEM;
4717 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4718 if (!hash)
4719 goto out_unlock;
4720
4721 INIT_HLIST_HEAD(&hhd);
4722
4723 size = 1 << hash->size_bits;
4724 for (i = 0; i < size; i++) {
4725 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4726
4727 if (func_g.search) {
4728 kallsyms_lookup(entry->ip, NULL, NULL,
4729 NULL, str);
4730 if (!ftrace_match(str, &func_g))
4731 continue;
4732 }
4733 count++;
4734 remove_hash_entry(hash, entry);
4735 hlist_add_head(&entry->hlist, &hhd);
4736 }
4737 }
4738
4739 /* Nothing found? */
4740 if (!count) {
4741 ret = -EINVAL;
4742 goto out_unlock;
4743 }
4744
4745 mutex_lock(&ftrace_lock);
4746
4747 WARN_ON(probe->ref < count);
4748
4749 probe->ref -= count;
4750
4751 if (ftrace_hash_empty(hash))
4752 ftrace_shutdown(&probe->ops, 0);
4753
4754 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4755 hash, 1);
4756
4757 /* still need to update the function call sites */
4758 if (ftrace_enabled && !ftrace_hash_empty(hash))
4759 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4760 &old_hash_ops);
4761 synchronize_rcu();
4762
4763 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4764 hlist_del(&entry->hlist);
4765 if (probe_ops->free)
4766 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4767 kfree(entry);
4768 }
4769 mutex_unlock(&ftrace_lock);
4770
4771 out_unlock:
4772 mutex_unlock(&probe->ops.func_hash->regex_lock);
4773 free_ftrace_hash(hash);
4774
4775 release_probe(probe);
4776
4777 return ret;
4778
4779 err_unlock_ftrace:
4780 mutex_unlock(&ftrace_lock);
4781 return ret;
4782}
4783
4784void clear_ftrace_function_probes(struct trace_array *tr)
4785{
4786 struct ftrace_func_probe *probe, *n;
4787
4788 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4789 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4790}
4791
4792static LIST_HEAD(ftrace_commands);
4793static DEFINE_MUTEX(ftrace_cmd_mutex);
4794
4795/*
4796 * Currently we only register ftrace commands from __init, so mark this
4797 * __init too.
4798 */
4799__init int register_ftrace_command(struct ftrace_func_command *cmd)
4800{
4801 struct ftrace_func_command *p;
4802 int ret = 0;
4803
4804 mutex_lock(&ftrace_cmd_mutex);
4805 list_for_each_entry(p, &ftrace_commands, list) {
4806 if (strcmp(cmd->name, p->name) == 0) {
4807 ret = -EBUSY;
4808 goto out_unlock;
4809 }
4810 }
4811 list_add(&cmd->list, &ftrace_commands);
4812 out_unlock:
4813 mutex_unlock(&ftrace_cmd_mutex);
4814
4815 return ret;
4816}
4817
4818/*
4819 * Currently we only unregister ftrace commands from __init, so mark
4820 * this __init too.
4821 */
4822__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4823{
4824 struct ftrace_func_command *p, *n;
4825 int ret = -ENODEV;
4826
4827 mutex_lock(&ftrace_cmd_mutex);
4828 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4829 if (strcmp(cmd->name, p->name) == 0) {
4830 ret = 0;
4831 list_del_init(&p->list);
4832 goto out_unlock;
4833 }
4834 }
4835 out_unlock:
4836 mutex_unlock(&ftrace_cmd_mutex);
4837
4838 return ret;
4839}
4840
4841static int ftrace_process_regex(struct ftrace_iterator *iter,
4842 char *buff, int len, int enable)
4843{
4844 struct ftrace_hash *hash = iter->hash;
4845 struct trace_array *tr = iter->ops->private;
4846 char *func, *command, *next = buff;
4847 struct ftrace_func_command *p;
4848 int ret = -EINVAL;
4849
4850 func = strsep(&next, ":");
4851
4852 if (!next) {
4853 ret = ftrace_match_records(hash, func, len);
4854 if (!ret)
4855 ret = -EINVAL;
4856 if (ret < 0)
4857 return ret;
4858 return 0;
4859 }
4860
4861 /* command found */
4862
4863 command = strsep(&next, ":");
4864
4865 mutex_lock(&ftrace_cmd_mutex);
4866 list_for_each_entry(p, &ftrace_commands, list) {
4867 if (strcmp(p->name, command) == 0) {
4868 ret = p->func(tr, hash, func, command, next, enable);
4869 goto out_unlock;
4870 }
4871 }
4872 out_unlock:
4873 mutex_unlock(&ftrace_cmd_mutex);
4874
4875 return ret;
4876}
4877
4878static ssize_t
4879ftrace_regex_write(struct file *file, const char __user *ubuf,
4880 size_t cnt, loff_t *ppos, int enable)
4881{
4882 struct ftrace_iterator *iter;
4883 struct trace_parser *parser;
4884 ssize_t ret, read;
4885
4886 if (!cnt)
4887 return 0;
4888
4889 if (file->f_mode & FMODE_READ) {
4890 struct seq_file *m = file->private_data;
4891 iter = m->private;
4892 } else
4893 iter = file->private_data;
4894
4895 if (unlikely(ftrace_disabled))
4896 return -ENODEV;
4897
4898 /* iter->hash is a local copy, so we don't need regex_lock */
4899
4900 parser = &iter->parser;
4901 read = trace_get_user(parser, ubuf, cnt, ppos);
4902
4903 if (read >= 0 && trace_parser_loaded(parser) &&
4904 !trace_parser_cont(parser)) {
4905 ret = ftrace_process_regex(iter, parser->buffer,
4906 parser->idx, enable);
4907 trace_parser_clear(parser);
4908 if (ret < 0)
4909 goto out;
4910 }
4911
4912 ret = read;
4913 out:
4914 return ret;
4915}
4916
4917ssize_t
4918ftrace_filter_write(struct file *file, const char __user *ubuf,
4919 size_t cnt, loff_t *ppos)
4920{
4921 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4922}
4923
4924ssize_t
4925ftrace_notrace_write(struct file *file, const char __user *ubuf,
4926 size_t cnt, loff_t *ppos)
4927{
4928 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4929}
4930
4931static int
4932ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4933{
4934 struct ftrace_func_entry *entry;
4935
4936 if (!ftrace_location(ip))
4937 return -EINVAL;
4938
4939 if (remove) {
4940 entry = ftrace_lookup_ip(hash, ip);
4941 if (!entry)
4942 return -ENOENT;
4943 free_hash_entry(hash, entry);
4944 return 0;
4945 }
4946
4947 return add_hash_entry(hash, ip);
4948}
4949
4950static int
4951ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4952 unsigned long ip, int remove, int reset, int enable)
4953{
4954 struct ftrace_hash **orig_hash;
4955 struct ftrace_hash *hash;
4956 int ret;
4957
4958 if (unlikely(ftrace_disabled))
4959 return -ENODEV;
4960
4961 mutex_lock(&ops->func_hash->regex_lock);
4962
4963 if (enable)
4964 orig_hash = &ops->func_hash->filter_hash;
4965 else
4966 orig_hash = &ops->func_hash->notrace_hash;
4967
4968 if (reset)
4969 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4970 else
4971 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4972
4973 if (!hash) {
4974 ret = -ENOMEM;
4975 goto out_regex_unlock;
4976 }
4977
4978 if (buf && !ftrace_match_records(hash, buf, len)) {
4979 ret = -EINVAL;
4980 goto out_regex_unlock;
4981 }
4982 if (ip) {
4983 ret = ftrace_match_addr(hash, ip, remove);
4984 if (ret < 0)
4985 goto out_regex_unlock;
4986 }
4987
4988 mutex_lock(&ftrace_lock);
4989 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4990 mutex_unlock(&ftrace_lock);
4991
4992 out_regex_unlock:
4993 mutex_unlock(&ops->func_hash->regex_lock);
4994
4995 free_ftrace_hash(hash);
4996 return ret;
4997}
4998
4999static int
5000ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
5001 int reset, int enable)
5002{
5003 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
5004}
5005
5006#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5007
5008struct ftrace_direct_func {
5009 struct list_head next;
5010 unsigned long addr;
5011 int count;
5012};
5013
5014static LIST_HEAD(ftrace_direct_funcs);
5015
5016/**
5017 * ftrace_find_direct_func - test an address if it is a registered direct caller
5018 * @addr: The address of a registered direct caller
5019 *
5020 * This searches to see if a ftrace direct caller has been registered
5021 * at a specific address, and if so, it returns a descriptor for it.
5022 *
5023 * This can be used by architecture code to see if an address is
5024 * a direct caller (trampoline) attached to a fentry/mcount location.
5025 * This is useful for the function_graph tracer, as it may need to
5026 * do adjustments if it traced a location that also has a direct
5027 * trampoline attached to it.
5028 */
5029struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5030{
5031 struct ftrace_direct_func *entry;
5032 bool found = false;
5033
5034 /* May be called by fgraph trampoline (protected by rcu tasks) */
5035 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5036 if (entry->addr == addr) {
5037 found = true;
5038 break;
5039 }
5040 }
5041 if (found)
5042 return entry;
5043
5044 return NULL;
5045}
5046
5047static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5048{
5049 struct ftrace_direct_func *direct;
5050
5051 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5052 if (!direct)
5053 return NULL;
5054 direct->addr = addr;
5055 direct->count = 0;
5056 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5057 ftrace_direct_func_count++;
5058 return direct;
5059}
5060
5061/**
5062 * register_ftrace_direct - Call a custom trampoline directly
5063 * @ip: The address of the nop at the beginning of a function
5064 * @addr: The address of the trampoline to call at @ip
5065 *
5066 * This is used to connect a direct call from the nop location (@ip)
5067 * at the start of ftrace traced functions. The location that it calls
5068 * (@addr) must be able to handle a direct call, and save the parameters
5069 * of the function being traced, and restore them (or inject new ones
5070 * if needed), before returning.
5071 *
5072 * Returns:
5073 * 0 on success
5074 * -EBUSY - Another direct function is already attached (there can be only one)
5075 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5076 * -ENOMEM - There was an allocation failure.
5077 */
5078int register_ftrace_direct(unsigned long ip, unsigned long addr)
5079{
5080 struct ftrace_direct_func *direct;
5081 struct ftrace_func_entry *entry;
5082 struct ftrace_hash *free_hash = NULL;
5083 struct dyn_ftrace *rec;
5084 int ret = -EBUSY;
5085
5086 mutex_lock(&direct_mutex);
5087
5088 /* See if there's a direct function at @ip already */
5089 if (ftrace_find_rec_direct(ip))
5090 goto out_unlock;
5091
5092 ret = -ENODEV;
5093 rec = lookup_rec(ip, ip);
5094 if (!rec)
5095 goto out_unlock;
5096
5097 /*
5098 * Check if the rec says it has a direct call but we didn't
5099 * find one earlier?
5100 */
5101 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5102 goto out_unlock;
5103
5104 /* Make sure the ip points to the exact record */
5105 if (ip != rec->ip) {
5106 ip = rec->ip;
5107 /* Need to check this ip for a direct. */
5108 if (ftrace_find_rec_direct(ip))
5109 goto out_unlock;
5110 }
5111
5112 ret = -ENOMEM;
5113 if (ftrace_hash_empty(direct_functions) ||
5114 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5115 struct ftrace_hash *new_hash;
5116 int size = ftrace_hash_empty(direct_functions) ? 0 :
5117 direct_functions->count + 1;
5118
5119 if (size < 32)
5120 size = 32;
5121
5122 new_hash = dup_hash(direct_functions, size);
5123 if (!new_hash)
5124 goto out_unlock;
5125
5126 free_hash = direct_functions;
5127 direct_functions = new_hash;
5128 }
5129
5130 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5131 if (!entry)
5132 goto out_unlock;
5133
5134 direct = ftrace_find_direct_func(addr);
5135 if (!direct) {
5136 direct = ftrace_alloc_direct_func(addr);
5137 if (!direct) {
5138 kfree(entry);
5139 goto out_unlock;
5140 }
5141 }
5142
5143 entry->ip = ip;
5144 entry->direct = addr;
5145 __add_hash_entry(direct_functions, entry);
5146
5147 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5148 if (ret)
5149 remove_hash_entry(direct_functions, entry);
5150
5151 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5152 ret = register_ftrace_function(&direct_ops);
5153 if (ret)
5154 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5155 }
5156
5157 if (ret) {
5158 kfree(entry);
5159 if (!direct->count) {
5160 list_del_rcu(&direct->next);
5161 synchronize_rcu_tasks();
5162 kfree(direct);
5163 if (free_hash)
5164 free_ftrace_hash(free_hash);
5165 free_hash = NULL;
5166 ftrace_direct_func_count--;
5167 }
5168 } else {
5169 direct->count++;
5170 }
5171 out_unlock:
5172 mutex_unlock(&direct_mutex);
5173
5174 if (free_hash) {
5175 synchronize_rcu_tasks();
5176 free_ftrace_hash(free_hash);
5177 }
5178
5179 return ret;
5180}
5181EXPORT_SYMBOL_GPL(register_ftrace_direct);
5182
5183static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5184 struct dyn_ftrace **recp)
5185{
5186 struct ftrace_func_entry *entry;
5187 struct dyn_ftrace *rec;
5188
5189 rec = lookup_rec(*ip, *ip);
5190 if (!rec)
5191 return NULL;
5192
5193 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5194 if (!entry) {
5195 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5196 return NULL;
5197 }
5198
5199 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5200
5201 /* Passed in ip just needs to be on the call site */
5202 *ip = rec->ip;
5203
5204 if (recp)
5205 *recp = rec;
5206
5207 return entry;
5208}
5209
5210int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5211{
5212 struct ftrace_direct_func *direct;
5213 struct ftrace_func_entry *entry;
5214 int ret = -ENODEV;
5215
5216 mutex_lock(&direct_mutex);
5217
5218 entry = find_direct_entry(&ip, NULL);
5219 if (!entry)
5220 goto out_unlock;
5221
5222 if (direct_functions->count == 1)
5223 unregister_ftrace_function(&direct_ops);
5224
5225 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5226
5227 WARN_ON(ret);
5228
5229 remove_hash_entry(direct_functions, entry);
5230
5231 direct = ftrace_find_direct_func(addr);
5232 if (!WARN_ON(!direct)) {
5233 /* This is the good path (see the ! before WARN) */
5234 direct->count--;
5235 WARN_ON(direct->count < 0);
5236 if (!direct->count) {
5237 list_del_rcu(&direct->next);
5238 synchronize_rcu_tasks();
5239 kfree(direct);
5240 kfree(entry);
5241 ftrace_direct_func_count--;
5242 }
5243 }
5244 out_unlock:
5245 mutex_unlock(&direct_mutex);
5246
5247 return ret;
5248}
5249EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5250
5251static struct ftrace_ops stub_ops = {
5252 .func = ftrace_stub,
5253};
5254
5255/**
5256 * ftrace_modify_direct_caller - modify ftrace nop directly
5257 * @entry: The ftrace hash entry of the direct helper for @rec
5258 * @rec: The record representing the function site to patch
5259 * @old_addr: The location that the site at @rec->ip currently calls
5260 * @new_addr: The location that the site at @rec->ip should call
5261 *
5262 * An architecture may overwrite this function to optimize the
5263 * changing of the direct callback on an ftrace nop location.
5264 * This is called with the ftrace_lock mutex held, and no other
5265 * ftrace callbacks are on the associated record (@rec). Thus,
5266 * it is safe to modify the ftrace record, where it should be
5267 * currently calling @old_addr directly, to call @new_addr.
5268 *
5269 * Safety checks should be made to make sure that the code at
5270 * @rec->ip is currently calling @old_addr. And this must
5271 * also update entry->direct to @new_addr.
5272 */
5273int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5274 struct dyn_ftrace *rec,
5275 unsigned long old_addr,
5276 unsigned long new_addr)
5277{
5278 unsigned long ip = rec->ip;
5279 int ret;
5280
5281 /*
5282 * The ftrace_lock was used to determine if the record
5283 * had more than one registered user to it. If it did,
5284 * we needed to prevent that from changing to do the quick
5285 * switch. But if it did not (only a direct caller was attached)
5286 * then this function is called. But this function can deal
5287 * with attached callers to the rec that we care about, and
5288 * since this function uses standard ftrace calls that take
5289 * the ftrace_lock mutex, we need to release it.
5290 */
5291 mutex_unlock(&ftrace_lock);
5292
5293 /*
5294 * By setting a stub function at the same address, we force
5295 * the code to call the iterator and the direct_ops helper.
5296 * This means that @ip does not call the direct call, and
5297 * we can simply modify it.
5298 */
5299 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5300 if (ret)
5301 goto out_lock;
5302
5303 ret = register_ftrace_function(&stub_ops);
5304 if (ret) {
5305 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5306 goto out_lock;
5307 }
5308
5309 entry->direct = new_addr;
5310
5311 /*
5312 * By removing the stub, we put back the direct call, calling
5313 * the @new_addr.
5314 */
5315 unregister_ftrace_function(&stub_ops);
5316 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5317
5318 out_lock:
5319 mutex_lock(&ftrace_lock);
5320
5321 return ret;
5322}
5323
5324/**
5325 * modify_ftrace_direct - Modify an existing direct call to call something else
5326 * @ip: The instruction pointer to modify
5327 * @old_addr: The address that the current @ip calls directly
5328 * @new_addr: The address that the @ip should call
5329 *
5330 * This modifies a ftrace direct caller at an instruction pointer without
5331 * having to disable it first. The direct call will switch over to the
5332 * @new_addr without missing anything.
5333 *
5334 * Returns: zero on success. Non zero on error, which includes:
5335 * -ENODEV : the @ip given has no direct caller attached
5336 * -EINVAL : the @old_addr does not match the current direct caller
5337 */
5338int modify_ftrace_direct(unsigned long ip,
5339 unsigned long old_addr, unsigned long new_addr)
5340{
5341 struct ftrace_direct_func *direct, *new_direct = NULL;
5342 struct ftrace_func_entry *entry;
5343 struct dyn_ftrace *rec;
5344 int ret = -ENODEV;
5345
5346 mutex_lock(&direct_mutex);
5347
5348 mutex_lock(&ftrace_lock);
5349 entry = find_direct_entry(&ip, &rec);
5350 if (!entry)
5351 goto out_unlock;
5352
5353 ret = -EINVAL;
5354 if (entry->direct != old_addr)
5355 goto out_unlock;
5356
5357 direct = ftrace_find_direct_func(old_addr);
5358 if (WARN_ON(!direct))
5359 goto out_unlock;
5360 if (direct->count > 1) {
5361 ret = -ENOMEM;
5362 new_direct = ftrace_alloc_direct_func(new_addr);
5363 if (!new_direct)
5364 goto out_unlock;
5365 direct->count--;
5366 new_direct->count++;
5367 } else {
5368 direct->addr = new_addr;
5369 }
5370
5371 /*
5372 * If there's no other ftrace callback on the rec->ip location,
5373 * then it can be changed directly by the architecture.
5374 * If there is another caller, then we just need to change the
5375 * direct caller helper to point to @new_addr.
5376 */
5377 if (ftrace_rec_count(rec) == 1) {
5378 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5379 } else {
5380 entry->direct = new_addr;
5381 ret = 0;
5382 }
5383
5384 if (unlikely(ret && new_direct)) {
5385 direct->count++;
5386 list_del_rcu(&new_direct->next);
5387 synchronize_rcu_tasks();
5388 kfree(new_direct);
5389 ftrace_direct_func_count--;
5390 }
5391
5392 out_unlock:
5393 mutex_unlock(&ftrace_lock);
5394 mutex_unlock(&direct_mutex);
5395 return ret;
5396}
5397EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5398#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5399
5400/**
5401 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5402 * @ops - the ops to set the filter with
5403 * @ip - the address to add to or remove from the filter.
5404 * @remove - non zero to remove the ip from the filter
5405 * @reset - non zero to reset all filters before applying this filter.
5406 *
5407 * Filters denote which functions should be enabled when tracing is enabled
5408 * If @ip is NULL, it fails to update filter.
5409 */
5410int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5411 int remove, int reset)
5412{
5413 ftrace_ops_init(ops);
5414 return ftrace_set_addr(ops, ip, remove, reset, 1);
5415}
5416EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5417
5418/**
5419 * ftrace_ops_set_global_filter - setup ops to use global filters
5420 * @ops - the ops which will use the global filters
5421 *
5422 * ftrace users who need global function trace filtering should call this.
5423 * It can set the global filter only if ops were not initialized before.
5424 */
5425void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5426{
5427 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5428 return;
5429
5430 ftrace_ops_init(ops);
5431 ops->func_hash = &global_ops.local_hash;
5432}
5433EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5434
5435static int
5436ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5437 int reset, int enable)
5438{
5439 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5440}
5441
5442/**
5443 * ftrace_set_filter - set a function to filter on in ftrace
5444 * @ops - the ops to set the filter with
5445 * @buf - the string that holds the function filter text.
5446 * @len - the length of the string.
5447 * @reset - non zero to reset all filters before applying this filter.
5448 *
5449 * Filters denote which functions should be enabled when tracing is enabled.
5450 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5451 */
5452int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5453 int len, int reset)
5454{
5455 ftrace_ops_init(ops);
5456 return ftrace_set_regex(ops, buf, len, reset, 1);
5457}
5458EXPORT_SYMBOL_GPL(ftrace_set_filter);
5459
5460/**
5461 * ftrace_set_notrace - set a function to not trace in ftrace
5462 * @ops - the ops to set the notrace filter with
5463 * @buf - the string that holds the function notrace text.
5464 * @len - the length of the string.
5465 * @reset - non zero to reset all filters before applying this filter.
5466 *
5467 * Notrace Filters denote which functions should not be enabled when tracing
5468 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5469 * for tracing.
5470 */
5471int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5472 int len, int reset)
5473{
5474 ftrace_ops_init(ops);
5475 return ftrace_set_regex(ops, buf, len, reset, 0);
5476}
5477EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5478/**
5479 * ftrace_set_global_filter - set a function to filter on with global tracers
5480 * @buf - the string that holds the function filter text.
5481 * @len - the length of the string.
5482 * @reset - non zero to reset all filters before applying this filter.
5483 *
5484 * Filters denote which functions should be enabled when tracing is enabled.
5485 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5486 */
5487void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5488{
5489 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5490}
5491EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5492
5493/**
5494 * ftrace_set_global_notrace - set a function to not trace with global tracers
5495 * @buf - the string that holds the function notrace text.
5496 * @len - the length of the string.
5497 * @reset - non zero to reset all filters before applying this filter.
5498 *
5499 * Notrace Filters denote which functions should not be enabled when tracing
5500 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5501 * for tracing.
5502 */
5503void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5504{
5505 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5506}
5507EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5508
5509/*
5510 * command line interface to allow users to set filters on boot up.
5511 */
5512#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5513static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5514static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5515
5516/* Used by function selftest to not test if filter is set */
5517bool ftrace_filter_param __initdata;
5518
5519static int __init set_ftrace_notrace(char *str)
5520{
5521 ftrace_filter_param = true;
5522 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5523 return 1;
5524}
5525__setup("ftrace_notrace=", set_ftrace_notrace);
5526
5527static int __init set_ftrace_filter(char *str)
5528{
5529 ftrace_filter_param = true;
5530 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5531 return 1;
5532}
5533__setup("ftrace_filter=", set_ftrace_filter);
5534
5535#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5536static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5537static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5538static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5539
5540static int __init set_graph_function(char *str)
5541{
5542 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5543 return 1;
5544}
5545__setup("ftrace_graph_filter=", set_graph_function);
5546
5547static int __init set_graph_notrace_function(char *str)
5548{
5549 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5550 return 1;
5551}
5552__setup("ftrace_graph_notrace=", set_graph_notrace_function);
5553
5554static int __init set_graph_max_depth_function(char *str)
5555{
5556 if (!str)
5557 return 0;
5558 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5559 return 1;
5560}
5561__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5562
5563static void __init set_ftrace_early_graph(char *buf, int enable)
5564{
5565 int ret;
5566 char *func;
5567 struct ftrace_hash *hash;
5568
5569 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5570 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5571 return;
5572
5573 while (buf) {
5574 func = strsep(&buf, ",");
5575 /* we allow only one expression at a time */
5576 ret = ftrace_graph_set_hash(hash, func);
5577 if (ret)
5578 printk(KERN_DEBUG "ftrace: function %s not "
5579 "traceable\n", func);
5580 }
5581
5582 if (enable)
5583 ftrace_graph_hash = hash;
5584 else
5585 ftrace_graph_notrace_hash = hash;
5586}
5587#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5588
5589void __init
5590ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5591{
5592 char *func;
5593
5594 ftrace_ops_init(ops);
5595
5596 while (buf) {
5597 func = strsep(&buf, ",");
5598 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5599 }
5600}
5601
5602static void __init set_ftrace_early_filters(void)
5603{
5604 if (ftrace_filter_buf[0])
5605 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5606 if (ftrace_notrace_buf[0])
5607 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5608#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5609 if (ftrace_graph_buf[0])
5610 set_ftrace_early_graph(ftrace_graph_buf, 1);
5611 if (ftrace_graph_notrace_buf[0])
5612 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5613#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5614}
5615
5616int ftrace_regex_release(struct inode *inode, struct file *file)
5617{
5618 struct seq_file *m = (struct seq_file *)file->private_data;
5619 struct ftrace_iterator *iter;
5620 struct ftrace_hash **orig_hash;
5621 struct trace_parser *parser;
5622 int filter_hash;
5623
5624 if (file->f_mode & FMODE_READ) {
5625 iter = m->private;
5626 seq_release(inode, file);
5627 } else
5628 iter = file->private_data;
5629
5630 parser = &iter->parser;
5631 if (trace_parser_loaded(parser)) {
5632 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5633
5634 ftrace_process_regex(iter, parser->buffer,
5635 parser->idx, enable);
5636 }
5637
5638 trace_parser_put(parser);
5639
5640 mutex_lock(&iter->ops->func_hash->regex_lock);
5641
5642 if (file->f_mode & FMODE_WRITE) {
5643 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5644
5645 if (filter_hash) {
5646 orig_hash = &iter->ops->func_hash->filter_hash;
5647 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5648 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5649 } else
5650 orig_hash = &iter->ops->func_hash->notrace_hash;
5651
5652 mutex_lock(&ftrace_lock);
5653 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5654 iter->hash, filter_hash);
5655 mutex_unlock(&ftrace_lock);
5656 } else {
5657 /* For read only, the hash is the ops hash */
5658 iter->hash = NULL;
5659 }
5660
5661 mutex_unlock(&iter->ops->func_hash->regex_lock);
5662 free_ftrace_hash(iter->hash);
5663 if (iter->tr)
5664 trace_array_put(iter->tr);
5665 kfree(iter);
5666
5667 return 0;
5668}
5669
5670static const struct file_operations ftrace_avail_fops = {
5671 .open = ftrace_avail_open,
5672 .read = seq_read,
5673 .llseek = seq_lseek,
5674 .release = seq_release_private,
5675};
5676
5677static const struct file_operations ftrace_enabled_fops = {
5678 .open = ftrace_enabled_open,
5679 .read = seq_read,
5680 .llseek = seq_lseek,
5681 .release = seq_release_private,
5682};
5683
5684static const struct file_operations ftrace_filter_fops = {
5685 .open = ftrace_filter_open,
5686 .read = seq_read,
5687 .write = ftrace_filter_write,
5688 .llseek = tracing_lseek,
5689 .release = ftrace_regex_release,
5690};
5691
5692static const struct file_operations ftrace_notrace_fops = {
5693 .open = ftrace_notrace_open,
5694 .read = seq_read,
5695 .write = ftrace_notrace_write,
5696 .llseek = tracing_lseek,
5697 .release = ftrace_regex_release,
5698};
5699
5700#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5701
5702static DEFINE_MUTEX(graph_lock);
5703
5704struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5705struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5706
5707enum graph_filter_type {
5708 GRAPH_FILTER_NOTRACE = 0,
5709 GRAPH_FILTER_FUNCTION,
5710};
5711
5712#define FTRACE_GRAPH_EMPTY ((void *)1)
5713
5714struct ftrace_graph_data {
5715 struct ftrace_hash *hash;
5716 struct ftrace_func_entry *entry;
5717 int idx; /* for hash table iteration */
5718 enum graph_filter_type type;
5719 struct ftrace_hash *new_hash;
5720 const struct seq_operations *seq_ops;
5721 struct trace_parser parser;
5722};
5723
5724static void *
5725__g_next(struct seq_file *m, loff_t *pos)
5726{
5727 struct ftrace_graph_data *fgd = m->private;
5728 struct ftrace_func_entry *entry = fgd->entry;
5729 struct hlist_head *head;
5730 int i, idx = fgd->idx;
5731
5732 if (*pos >= fgd->hash->count)
5733 return NULL;
5734
5735 if (entry) {
5736 hlist_for_each_entry_continue(entry, hlist) {
5737 fgd->entry = entry;
5738 return entry;
5739 }
5740
5741 idx++;
5742 }
5743
5744 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5745 head = &fgd->hash->buckets[i];
5746 hlist_for_each_entry(entry, head, hlist) {
5747 fgd->entry = entry;
5748 fgd->idx = i;
5749 return entry;
5750 }
5751 }
5752 return NULL;
5753}
5754
5755static void *
5756g_next(struct seq_file *m, void *v, loff_t *pos)
5757{
5758 (*pos)++;
5759 return __g_next(m, pos);
5760}
5761
5762static void *g_start(struct seq_file *m, loff_t *pos)
5763{
5764 struct ftrace_graph_data *fgd = m->private;
5765
5766 mutex_lock(&graph_lock);
5767
5768 if (fgd->type == GRAPH_FILTER_FUNCTION)
5769 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5770 lockdep_is_held(&graph_lock));
5771 else
5772 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5773 lockdep_is_held(&graph_lock));
5774
5775 /* Nothing, tell g_show to print all functions are enabled */
5776 if (ftrace_hash_empty(fgd->hash) && !*pos)
5777 return FTRACE_GRAPH_EMPTY;
5778
5779 fgd->idx = 0;
5780 fgd->entry = NULL;
5781 return __g_next(m, pos);
5782}
5783
5784static void g_stop(struct seq_file *m, void *p)
5785{
5786 mutex_unlock(&graph_lock);
5787}
5788
5789static int g_show(struct seq_file *m, void *v)
5790{
5791 struct ftrace_func_entry *entry = v;
5792
5793 if (!entry)
5794 return 0;
5795
5796 if (entry == FTRACE_GRAPH_EMPTY) {
5797 struct ftrace_graph_data *fgd = m->private;
5798
5799 if (fgd->type == GRAPH_FILTER_FUNCTION)
5800 seq_puts(m, "#### all functions enabled ####\n");
5801 else
5802 seq_puts(m, "#### no functions disabled ####\n");
5803 return 0;
5804 }
5805
5806 seq_printf(m, "%ps\n", (void *)entry->ip);
5807
5808 return 0;
5809}
5810
5811static const struct seq_operations ftrace_graph_seq_ops = {
5812 .start = g_start,
5813 .next = g_next,
5814 .stop = g_stop,
5815 .show = g_show,
5816};
5817
5818static int
5819__ftrace_graph_open(struct inode *inode, struct file *file,
5820 struct ftrace_graph_data *fgd)
5821{
5822 int ret;
5823 struct ftrace_hash *new_hash = NULL;
5824
5825 ret = security_locked_down(LOCKDOWN_TRACEFS);
5826 if (ret)
5827 return ret;
5828
5829 if (file->f_mode & FMODE_WRITE) {
5830 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5831
5832 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5833 return -ENOMEM;
5834
5835 if (file->f_flags & O_TRUNC)
5836 new_hash = alloc_ftrace_hash(size_bits);
5837 else
5838 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5839 fgd->hash);
5840 if (!new_hash) {
5841 ret = -ENOMEM;
5842 goto out;
5843 }
5844 }
5845
5846 if (file->f_mode & FMODE_READ) {
5847 ret = seq_open(file, &ftrace_graph_seq_ops);
5848 if (!ret) {
5849 struct seq_file *m = file->private_data;
5850 m->private = fgd;
5851 } else {
5852 /* Failed */
5853 free_ftrace_hash(new_hash);
5854 new_hash = NULL;
5855 }
5856 } else
5857 file->private_data = fgd;
5858
5859out:
5860 if (ret < 0 && file->f_mode & FMODE_WRITE)
5861 trace_parser_put(&fgd->parser);
5862
5863 fgd->new_hash = new_hash;
5864
5865 /*
5866 * All uses of fgd->hash must be taken with the graph_lock
5867 * held. The graph_lock is going to be released, so force
5868 * fgd->hash to be reinitialized when it is taken again.
5869 */
5870 fgd->hash = NULL;
5871
5872 return ret;
5873}
5874
5875static int
5876ftrace_graph_open(struct inode *inode, struct file *file)
5877{
5878 struct ftrace_graph_data *fgd;
5879 int ret;
5880
5881 if (unlikely(ftrace_disabled))
5882 return -ENODEV;
5883
5884 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5885 if (fgd == NULL)
5886 return -ENOMEM;
5887
5888 mutex_lock(&graph_lock);
5889
5890 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5891 lockdep_is_held(&graph_lock));
5892 fgd->type = GRAPH_FILTER_FUNCTION;
5893 fgd->seq_ops = &ftrace_graph_seq_ops;
5894
5895 ret = __ftrace_graph_open(inode, file, fgd);
5896 if (ret < 0)
5897 kfree(fgd);
5898
5899 mutex_unlock(&graph_lock);
5900 return ret;
5901}
5902
5903static int
5904ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5905{
5906 struct ftrace_graph_data *fgd;
5907 int ret;
5908
5909 if (unlikely(ftrace_disabled))
5910 return -ENODEV;
5911
5912 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5913 if (fgd == NULL)
5914 return -ENOMEM;
5915
5916 mutex_lock(&graph_lock);
5917
5918 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5919 lockdep_is_held(&graph_lock));
5920 fgd->type = GRAPH_FILTER_NOTRACE;
5921 fgd->seq_ops = &ftrace_graph_seq_ops;
5922
5923 ret = __ftrace_graph_open(inode, file, fgd);
5924 if (ret < 0)
5925 kfree(fgd);
5926
5927 mutex_unlock(&graph_lock);
5928 return ret;
5929}
5930
5931static int
5932ftrace_graph_release(struct inode *inode, struct file *file)
5933{
5934 struct ftrace_graph_data *fgd;
5935 struct ftrace_hash *old_hash, *new_hash;
5936 struct trace_parser *parser;
5937 int ret = 0;
5938
5939 if (file->f_mode & FMODE_READ) {
5940 struct seq_file *m = file->private_data;
5941
5942 fgd = m->private;
5943 seq_release(inode, file);
5944 } else {
5945 fgd = file->private_data;
5946 }
5947
5948
5949 if (file->f_mode & FMODE_WRITE) {
5950
5951 parser = &fgd->parser;
5952
5953 if (trace_parser_loaded((parser))) {
5954 ret = ftrace_graph_set_hash(fgd->new_hash,
5955 parser->buffer);
5956 }
5957
5958 trace_parser_put(parser);
5959
5960 new_hash = __ftrace_hash_move(fgd->new_hash);
5961 if (!new_hash) {
5962 ret = -ENOMEM;
5963 goto out;
5964 }
5965
5966 mutex_lock(&graph_lock);
5967
5968 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5969 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5970 lockdep_is_held(&graph_lock));
5971 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5972 } else {
5973 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5974 lockdep_is_held(&graph_lock));
5975 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5976 }
5977
5978 mutex_unlock(&graph_lock);
5979
5980 /*
5981 * We need to do a hard force of sched synchronization.
5982 * This is because we use preempt_disable() to do RCU, but
5983 * the function tracers can be called where RCU is not watching
5984 * (like before user_exit()). We can not rely on the RCU
5985 * infrastructure to do the synchronization, thus we must do it
5986 * ourselves.
5987 */
5988 if (old_hash != EMPTY_HASH)
5989 synchronize_rcu_tasks_rude();
5990
5991 free_ftrace_hash(old_hash);
5992 }
5993
5994 out:
5995 free_ftrace_hash(fgd->new_hash);
5996 kfree(fgd);
5997
5998 return ret;
5999}
6000
6001static int
6002ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6003{
6004 struct ftrace_glob func_g;
6005 struct dyn_ftrace *rec;
6006 struct ftrace_page *pg;
6007 struct ftrace_func_entry *entry;
6008 int fail = 1;
6009 int not;
6010
6011 /* decode regex */
6012 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6013 &func_g.search, ¬);
6014
6015 func_g.len = strlen(func_g.search);
6016
6017 mutex_lock(&ftrace_lock);
6018
6019 if (unlikely(ftrace_disabled)) {
6020 mutex_unlock(&ftrace_lock);
6021 return -ENODEV;
6022 }
6023
6024 do_for_each_ftrace_rec(pg, rec) {
6025
6026 if (rec->flags & FTRACE_FL_DISABLED)
6027 continue;
6028
6029 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6030 entry = ftrace_lookup_ip(hash, rec->ip);
6031
6032 if (!not) {
6033 fail = 0;
6034
6035 if (entry)
6036 continue;
6037 if (add_hash_entry(hash, rec->ip) < 0)
6038 goto out;
6039 } else {
6040 if (entry) {
6041 free_hash_entry(hash, entry);
6042 fail = 0;
6043 }
6044 }
6045 }
6046 } while_for_each_ftrace_rec();
6047out:
6048 mutex_unlock(&ftrace_lock);
6049
6050 if (fail)
6051 return -EINVAL;
6052
6053 return 0;
6054}
6055
6056static ssize_t
6057ftrace_graph_write(struct file *file, const char __user *ubuf,
6058 size_t cnt, loff_t *ppos)
6059{
6060 ssize_t read, ret = 0;
6061 struct ftrace_graph_data *fgd = file->private_data;
6062 struct trace_parser *parser;
6063
6064 if (!cnt)
6065 return 0;
6066
6067 /* Read mode uses seq functions */
6068 if (file->f_mode & FMODE_READ) {
6069 struct seq_file *m = file->private_data;
6070 fgd = m->private;
6071 }
6072
6073 parser = &fgd->parser;
6074
6075 read = trace_get_user(parser, ubuf, cnt, ppos);
6076
6077 if (read >= 0 && trace_parser_loaded(parser) &&
6078 !trace_parser_cont(parser)) {
6079
6080 ret = ftrace_graph_set_hash(fgd->new_hash,
6081 parser->buffer);
6082 trace_parser_clear(parser);
6083 }
6084
6085 if (!ret)
6086 ret = read;
6087
6088 return ret;
6089}
6090
6091static const struct file_operations ftrace_graph_fops = {
6092 .open = ftrace_graph_open,
6093 .read = seq_read,
6094 .write = ftrace_graph_write,
6095 .llseek = tracing_lseek,
6096 .release = ftrace_graph_release,
6097};
6098
6099static const struct file_operations ftrace_graph_notrace_fops = {
6100 .open = ftrace_graph_notrace_open,
6101 .read = seq_read,
6102 .write = ftrace_graph_write,
6103 .llseek = tracing_lseek,
6104 .release = ftrace_graph_release,
6105};
6106#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6107
6108void ftrace_create_filter_files(struct ftrace_ops *ops,
6109 struct dentry *parent)
6110{
6111
6112 trace_create_file("set_ftrace_filter", 0644, parent,
6113 ops, &ftrace_filter_fops);
6114
6115 trace_create_file("set_ftrace_notrace", 0644, parent,
6116 ops, &ftrace_notrace_fops);
6117}
6118
6119/*
6120 * The name "destroy_filter_files" is really a misnomer. Although
6121 * in the future, it may actually delete the files, but this is
6122 * really intended to make sure the ops passed in are disabled
6123 * and that when this function returns, the caller is free to
6124 * free the ops.
6125 *
6126 * The "destroy" name is only to match the "create" name that this
6127 * should be paired with.
6128 */
6129void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6130{
6131 mutex_lock(&ftrace_lock);
6132 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6133 ftrace_shutdown(ops, 0);
6134 ops->flags |= FTRACE_OPS_FL_DELETED;
6135 ftrace_free_filter(ops);
6136 mutex_unlock(&ftrace_lock);
6137}
6138
6139static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6140{
6141
6142 trace_create_file("available_filter_functions", 0444,
6143 d_tracer, NULL, &ftrace_avail_fops);
6144
6145 trace_create_file("enabled_functions", 0444,
6146 d_tracer, NULL, &ftrace_enabled_fops);
6147
6148 ftrace_create_filter_files(&global_ops, d_tracer);
6149
6150#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6151 trace_create_file("set_graph_function", 0644, d_tracer,
6152 NULL,
6153 &ftrace_graph_fops);
6154 trace_create_file("set_graph_notrace", 0644, d_tracer,
6155 NULL,
6156 &ftrace_graph_notrace_fops);
6157#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6158
6159 return 0;
6160}
6161
6162static int ftrace_cmp_ips(const void *a, const void *b)
6163{
6164 const unsigned long *ipa = a;
6165 const unsigned long *ipb = b;
6166
6167 if (*ipa > *ipb)
6168 return 1;
6169 if (*ipa < *ipb)
6170 return -1;
6171 return 0;
6172}
6173
6174static int ftrace_process_locs(struct module *mod,
6175 unsigned long *start,
6176 unsigned long *end)
6177{
6178 struct ftrace_page *start_pg;
6179 struct ftrace_page *pg;
6180 struct dyn_ftrace *rec;
6181 unsigned long count;
6182 unsigned long *p;
6183 unsigned long addr;
6184 unsigned long flags = 0; /* Shut up gcc */
6185 int ret = -ENOMEM;
6186
6187 count = end - start;
6188
6189 if (!count)
6190 return 0;
6191
6192 sort(start, count, sizeof(*start),
6193 ftrace_cmp_ips, NULL);
6194
6195 start_pg = ftrace_allocate_pages(count);
6196 if (!start_pg)
6197 return -ENOMEM;
6198
6199 mutex_lock(&ftrace_lock);
6200
6201 /*
6202 * Core and each module needs their own pages, as
6203 * modules will free them when they are removed.
6204 * Force a new page to be allocated for modules.
6205 */
6206 if (!mod) {
6207 WARN_ON(ftrace_pages || ftrace_pages_start);
6208 /* First initialization */
6209 ftrace_pages = ftrace_pages_start = start_pg;
6210 } else {
6211 if (!ftrace_pages)
6212 goto out;
6213
6214 if (WARN_ON(ftrace_pages->next)) {
6215 /* Hmm, we have free pages? */
6216 while (ftrace_pages->next)
6217 ftrace_pages = ftrace_pages->next;
6218 }
6219
6220 ftrace_pages->next = start_pg;
6221 }
6222
6223 p = start;
6224 pg = start_pg;
6225 while (p < end) {
6226 unsigned long end_offset;
6227 addr = ftrace_call_adjust(*p++);
6228 /*
6229 * Some architecture linkers will pad between
6230 * the different mcount_loc sections of different
6231 * object files to satisfy alignments.
6232 * Skip any NULL pointers.
6233 */
6234 if (!addr)
6235 continue;
6236
6237 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6238 if (end_offset > PAGE_SIZE << pg->order) {
6239 /* We should have allocated enough */
6240 if (WARN_ON(!pg->next))
6241 break;
6242 pg = pg->next;
6243 }
6244
6245 rec = &pg->records[pg->index++];
6246 rec->ip = addr;
6247 }
6248
6249 /* We should have used all pages */
6250 WARN_ON(pg->next);
6251
6252 /* Assign the last page to ftrace_pages */
6253 ftrace_pages = pg;
6254
6255 /*
6256 * We only need to disable interrupts on start up
6257 * because we are modifying code that an interrupt
6258 * may execute, and the modification is not atomic.
6259 * But for modules, nothing runs the code we modify
6260 * until we are finished with it, and there's no
6261 * reason to cause large interrupt latencies while we do it.
6262 */
6263 if (!mod)
6264 local_irq_save(flags);
6265 ftrace_update_code(mod, start_pg);
6266 if (!mod)
6267 local_irq_restore(flags);
6268 ret = 0;
6269 out:
6270 mutex_unlock(&ftrace_lock);
6271
6272 return ret;
6273}
6274
6275struct ftrace_mod_func {
6276 struct list_head list;
6277 char *name;
6278 unsigned long ip;
6279 unsigned int size;
6280};
6281
6282struct ftrace_mod_map {
6283 struct rcu_head rcu;
6284 struct list_head list;
6285 struct module *mod;
6286 unsigned long start_addr;
6287 unsigned long end_addr;
6288 struct list_head funcs;
6289 unsigned int num_funcs;
6290};
6291
6292static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6293 unsigned long *value, char *type,
6294 char *name, char *module_name,
6295 int *exported)
6296{
6297 struct ftrace_ops *op;
6298
6299 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6300 if (!op->trampoline || symnum--)
6301 continue;
6302 *value = op->trampoline;
6303 *type = 't';
6304 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6305 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6306 *exported = 0;
6307 return 0;
6308 }
6309
6310 return -ERANGE;
6311}
6312
6313#ifdef CONFIG_MODULES
6314
6315#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6316
6317static LIST_HEAD(ftrace_mod_maps);
6318
6319static int referenced_filters(struct dyn_ftrace *rec)
6320{
6321 struct ftrace_ops *ops;
6322 int cnt = 0;
6323
6324 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6325 if (ops_references_rec(ops, rec)) {
6326 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6327 continue;
6328 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6329 continue;
6330 cnt++;
6331 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6332 rec->flags |= FTRACE_FL_REGS;
6333 if (cnt == 1 && ops->trampoline)
6334 rec->flags |= FTRACE_FL_TRAMP;
6335 else
6336 rec->flags &= ~FTRACE_FL_TRAMP;
6337 }
6338 }
6339
6340 return cnt;
6341}
6342
6343static void
6344clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6345{
6346 struct ftrace_func_entry *entry;
6347 struct dyn_ftrace *rec;
6348 int i;
6349
6350 if (ftrace_hash_empty(hash))
6351 return;
6352
6353 for (i = 0; i < pg->index; i++) {
6354 rec = &pg->records[i];
6355 entry = __ftrace_lookup_ip(hash, rec->ip);
6356 /*
6357 * Do not allow this rec to match again.
6358 * Yeah, it may waste some memory, but will be removed
6359 * if/when the hash is modified again.
6360 */
6361 if (entry)
6362 entry->ip = 0;
6363 }
6364}
6365
6366/* Clear any records from hashes */
6367static void clear_mod_from_hashes(struct ftrace_page *pg)
6368{
6369 struct trace_array *tr;
6370
6371 mutex_lock(&trace_types_lock);
6372 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6373 if (!tr->ops || !tr->ops->func_hash)
6374 continue;
6375 mutex_lock(&tr->ops->func_hash->regex_lock);
6376 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6377 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6378 mutex_unlock(&tr->ops->func_hash->regex_lock);
6379 }
6380 mutex_unlock(&trace_types_lock);
6381}
6382
6383static void ftrace_free_mod_map(struct rcu_head *rcu)
6384{
6385 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6386 struct ftrace_mod_func *mod_func;
6387 struct ftrace_mod_func *n;
6388
6389 /* All the contents of mod_map are now not visible to readers */
6390 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6391 kfree(mod_func->name);
6392 list_del(&mod_func->list);
6393 kfree(mod_func);
6394 }
6395
6396 kfree(mod_map);
6397}
6398
6399void ftrace_release_mod(struct module *mod)
6400{
6401 struct ftrace_mod_map *mod_map;
6402 struct ftrace_mod_map *n;
6403 struct dyn_ftrace *rec;
6404 struct ftrace_page **last_pg;
6405 struct ftrace_page *tmp_page = NULL;
6406 struct ftrace_page *pg;
6407
6408 mutex_lock(&ftrace_lock);
6409
6410 if (ftrace_disabled)
6411 goto out_unlock;
6412
6413 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6414 if (mod_map->mod == mod) {
6415 list_del_rcu(&mod_map->list);
6416 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6417 break;
6418 }
6419 }
6420
6421 /*
6422 * Each module has its own ftrace_pages, remove
6423 * them from the list.
6424 */
6425 last_pg = &ftrace_pages_start;
6426 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6427 rec = &pg->records[0];
6428 if (within_module_core(rec->ip, mod) ||
6429 within_module_init(rec->ip, mod)) {
6430 /*
6431 * As core pages are first, the first
6432 * page should never be a module page.
6433 */
6434 if (WARN_ON(pg == ftrace_pages_start))
6435 goto out_unlock;
6436
6437 /* Check if we are deleting the last page */
6438 if (pg == ftrace_pages)
6439 ftrace_pages = next_to_ftrace_page(last_pg);
6440
6441 ftrace_update_tot_cnt -= pg->index;
6442 *last_pg = pg->next;
6443
6444 pg->next = tmp_page;
6445 tmp_page = pg;
6446 } else
6447 last_pg = &pg->next;
6448 }
6449 out_unlock:
6450 mutex_unlock(&ftrace_lock);
6451
6452 for (pg = tmp_page; pg; pg = tmp_page) {
6453
6454 /* Needs to be called outside of ftrace_lock */
6455 clear_mod_from_hashes(pg);
6456
6457 if (pg->records) {
6458 free_pages((unsigned long)pg->records, pg->order);
6459 ftrace_number_of_pages -= 1 << pg->order;
6460 }
6461 tmp_page = pg->next;
6462 kfree(pg);
6463 ftrace_number_of_groups--;
6464 }
6465}
6466
6467void ftrace_module_enable(struct module *mod)
6468{
6469 struct dyn_ftrace *rec;
6470 struct ftrace_page *pg;
6471
6472 mutex_lock(&ftrace_lock);
6473
6474 if (ftrace_disabled)
6475 goto out_unlock;
6476
6477 /*
6478 * If the tracing is enabled, go ahead and enable the record.
6479 *
6480 * The reason not to enable the record immediately is the
6481 * inherent check of ftrace_make_nop/ftrace_make_call for
6482 * correct previous instructions. Making first the NOP
6483 * conversion puts the module to the correct state, thus
6484 * passing the ftrace_make_call check.
6485 *
6486 * We also delay this to after the module code already set the
6487 * text to read-only, as we now need to set it back to read-write
6488 * so that we can modify the text.
6489 */
6490 if (ftrace_start_up)
6491 ftrace_arch_code_modify_prepare();
6492
6493 do_for_each_ftrace_rec(pg, rec) {
6494 int cnt;
6495 /*
6496 * do_for_each_ftrace_rec() is a double loop.
6497 * module text shares the pg. If a record is
6498 * not part of this module, then skip this pg,
6499 * which the "break" will do.
6500 */
6501 if (!within_module_core(rec->ip, mod) &&
6502 !within_module_init(rec->ip, mod))
6503 break;
6504
6505 cnt = 0;
6506
6507 /*
6508 * When adding a module, we need to check if tracers are
6509 * currently enabled and if they are, and can trace this record,
6510 * we need to enable the module functions as well as update the
6511 * reference counts for those function records.
6512 */
6513 if (ftrace_start_up)
6514 cnt += referenced_filters(rec);
6515
6516 rec->flags &= ~FTRACE_FL_DISABLED;
6517 rec->flags += cnt;
6518
6519 if (ftrace_start_up && cnt) {
6520 int failed = __ftrace_replace_code(rec, 1);
6521 if (failed) {
6522 ftrace_bug(failed, rec);
6523 goto out_loop;
6524 }
6525 }
6526
6527 } while_for_each_ftrace_rec();
6528
6529 out_loop:
6530 if (ftrace_start_up)
6531 ftrace_arch_code_modify_post_process();
6532
6533 out_unlock:
6534 mutex_unlock(&ftrace_lock);
6535
6536 process_cached_mods(mod->name);
6537}
6538
6539void ftrace_module_init(struct module *mod)
6540{
6541 if (ftrace_disabled || !mod->num_ftrace_callsites)
6542 return;
6543
6544 ftrace_process_locs(mod, mod->ftrace_callsites,
6545 mod->ftrace_callsites + mod->num_ftrace_callsites);
6546}
6547
6548static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6549 struct dyn_ftrace *rec)
6550{
6551 struct ftrace_mod_func *mod_func;
6552 unsigned long symsize;
6553 unsigned long offset;
6554 char str[KSYM_SYMBOL_LEN];
6555 char *modname;
6556 const char *ret;
6557
6558 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6559 if (!ret)
6560 return;
6561
6562 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6563 if (!mod_func)
6564 return;
6565
6566 mod_func->name = kstrdup(str, GFP_KERNEL);
6567 if (!mod_func->name) {
6568 kfree(mod_func);
6569 return;
6570 }
6571
6572 mod_func->ip = rec->ip - offset;
6573 mod_func->size = symsize;
6574
6575 mod_map->num_funcs++;
6576
6577 list_add_rcu(&mod_func->list, &mod_map->funcs);
6578}
6579
6580static struct ftrace_mod_map *
6581allocate_ftrace_mod_map(struct module *mod,
6582 unsigned long start, unsigned long end)
6583{
6584 struct ftrace_mod_map *mod_map;
6585
6586 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6587 if (!mod_map)
6588 return NULL;
6589
6590 mod_map->mod = mod;
6591 mod_map->start_addr = start;
6592 mod_map->end_addr = end;
6593 mod_map->num_funcs = 0;
6594
6595 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6596
6597 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6598
6599 return mod_map;
6600}
6601
6602static const char *
6603ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6604 unsigned long addr, unsigned long *size,
6605 unsigned long *off, char *sym)
6606{
6607 struct ftrace_mod_func *found_func = NULL;
6608 struct ftrace_mod_func *mod_func;
6609
6610 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6611 if (addr >= mod_func->ip &&
6612 addr < mod_func->ip + mod_func->size) {
6613 found_func = mod_func;
6614 break;
6615 }
6616 }
6617
6618 if (found_func) {
6619 if (size)
6620 *size = found_func->size;
6621 if (off)
6622 *off = addr - found_func->ip;
6623 if (sym)
6624 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6625
6626 return found_func->name;
6627 }
6628
6629 return NULL;
6630}
6631
6632const char *
6633ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6634 unsigned long *off, char **modname, char *sym)
6635{
6636 struct ftrace_mod_map *mod_map;
6637 const char *ret = NULL;
6638
6639 /* mod_map is freed via call_rcu() */
6640 preempt_disable();
6641 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6642 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6643 if (ret) {
6644 if (modname)
6645 *modname = mod_map->mod->name;
6646 break;
6647 }
6648 }
6649 preempt_enable();
6650
6651 return ret;
6652}
6653
6654int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6655 char *type, char *name,
6656 char *module_name, int *exported)
6657{
6658 struct ftrace_mod_map *mod_map;
6659 struct ftrace_mod_func *mod_func;
6660 int ret;
6661
6662 preempt_disable();
6663 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6664
6665 if (symnum >= mod_map->num_funcs) {
6666 symnum -= mod_map->num_funcs;
6667 continue;
6668 }
6669
6670 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6671 if (symnum > 1) {
6672 symnum--;
6673 continue;
6674 }
6675
6676 *value = mod_func->ip;
6677 *type = 'T';
6678 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6679 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6680 *exported = 1;
6681 preempt_enable();
6682 return 0;
6683 }
6684 WARN_ON(1);
6685 break;
6686 }
6687 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6688 module_name, exported);
6689 preempt_enable();
6690 return ret;
6691}
6692
6693#else
6694static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6695 struct dyn_ftrace *rec) { }
6696static inline struct ftrace_mod_map *
6697allocate_ftrace_mod_map(struct module *mod,
6698 unsigned long start, unsigned long end)
6699{
6700 return NULL;
6701}
6702int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6703 char *type, char *name, char *module_name,
6704 int *exported)
6705{
6706 int ret;
6707
6708 preempt_disable();
6709 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6710 module_name, exported);
6711 preempt_enable();
6712 return ret;
6713}
6714#endif /* CONFIG_MODULES */
6715
6716struct ftrace_init_func {
6717 struct list_head list;
6718 unsigned long ip;
6719};
6720
6721/* Clear any init ips from hashes */
6722static void
6723clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6724{
6725 struct ftrace_func_entry *entry;
6726
6727 entry = ftrace_lookup_ip(hash, func->ip);
6728 /*
6729 * Do not allow this rec to match again.
6730 * Yeah, it may waste some memory, but will be removed
6731 * if/when the hash is modified again.
6732 */
6733 if (entry)
6734 entry->ip = 0;
6735}
6736
6737static void
6738clear_func_from_hashes(struct ftrace_init_func *func)
6739{
6740 struct trace_array *tr;
6741
6742 mutex_lock(&trace_types_lock);
6743 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6744 if (!tr->ops || !tr->ops->func_hash)
6745 continue;
6746 mutex_lock(&tr->ops->func_hash->regex_lock);
6747 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6748 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6749 mutex_unlock(&tr->ops->func_hash->regex_lock);
6750 }
6751 mutex_unlock(&trace_types_lock);
6752}
6753
6754static void add_to_clear_hash_list(struct list_head *clear_list,
6755 struct dyn_ftrace *rec)
6756{
6757 struct ftrace_init_func *func;
6758
6759 func = kmalloc(sizeof(*func), GFP_KERNEL);
6760 if (!func) {
6761 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6762 return;
6763 }
6764
6765 func->ip = rec->ip;
6766 list_add(&func->list, clear_list);
6767}
6768
6769void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6770{
6771 unsigned long start = (unsigned long)(start_ptr);
6772 unsigned long end = (unsigned long)(end_ptr);
6773 struct ftrace_page **last_pg = &ftrace_pages_start;
6774 struct ftrace_page *pg;
6775 struct dyn_ftrace *rec;
6776 struct dyn_ftrace key;
6777 struct ftrace_mod_map *mod_map = NULL;
6778 struct ftrace_init_func *func, *func_next;
6779 struct list_head clear_hash;
6780
6781 INIT_LIST_HEAD(&clear_hash);
6782
6783 key.ip = start;
6784 key.flags = end; /* overload flags, as it is unsigned long */
6785
6786 mutex_lock(&ftrace_lock);
6787
6788 /*
6789 * If we are freeing module init memory, then check if
6790 * any tracer is active. If so, we need to save a mapping of
6791 * the module functions being freed with the address.
6792 */
6793 if (mod && ftrace_ops_list != &ftrace_list_end)
6794 mod_map = allocate_ftrace_mod_map(mod, start, end);
6795
6796 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6797 if (end < pg->records[0].ip ||
6798 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6799 continue;
6800 again:
6801 rec = bsearch(&key, pg->records, pg->index,
6802 sizeof(struct dyn_ftrace),
6803 ftrace_cmp_recs);
6804 if (!rec)
6805 continue;
6806
6807 /* rec will be cleared from hashes after ftrace_lock unlock */
6808 add_to_clear_hash_list(&clear_hash, rec);
6809
6810 if (mod_map)
6811 save_ftrace_mod_rec(mod_map, rec);
6812
6813 pg->index--;
6814 ftrace_update_tot_cnt--;
6815 if (!pg->index) {
6816 *last_pg = pg->next;
6817 if (pg->records) {
6818 free_pages((unsigned long)pg->records, pg->order);
6819 ftrace_number_of_pages -= 1 << pg->order;
6820 }
6821 ftrace_number_of_groups--;
6822 kfree(pg);
6823 pg = container_of(last_pg, struct ftrace_page, next);
6824 if (!(*last_pg))
6825 ftrace_pages = pg;
6826 continue;
6827 }
6828 memmove(rec, rec + 1,
6829 (pg->index - (rec - pg->records)) * sizeof(*rec));
6830 /* More than one function may be in this block */
6831 goto again;
6832 }
6833 mutex_unlock(&ftrace_lock);
6834
6835 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6836 clear_func_from_hashes(func);
6837 kfree(func);
6838 }
6839}
6840
6841void __init ftrace_free_init_mem(void)
6842{
6843 void *start = (void *)(&__init_begin);
6844 void *end = (void *)(&__init_end);
6845
6846 ftrace_free_mem(NULL, start, end);
6847}
6848
6849void __init ftrace_init(void)
6850{
6851 extern unsigned long __start_mcount_loc[];
6852 extern unsigned long __stop_mcount_loc[];
6853 unsigned long count, flags;
6854 int ret;
6855
6856 local_irq_save(flags);
6857 ret = ftrace_dyn_arch_init();
6858 local_irq_restore(flags);
6859 if (ret)
6860 goto failed;
6861
6862 count = __stop_mcount_loc - __start_mcount_loc;
6863 if (!count) {
6864 pr_info("ftrace: No functions to be traced?\n");
6865 goto failed;
6866 }
6867
6868 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6869 count, count / ENTRIES_PER_PAGE + 1);
6870
6871 last_ftrace_enabled = ftrace_enabled = 1;
6872
6873 ret = ftrace_process_locs(NULL,
6874 __start_mcount_loc,
6875 __stop_mcount_loc);
6876
6877 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6878 ftrace_number_of_pages, ftrace_number_of_groups);
6879
6880 set_ftrace_early_filters();
6881
6882 return;
6883 failed:
6884 ftrace_disabled = 1;
6885}
6886
6887/* Do nothing if arch does not support this */
6888void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6889{
6890}
6891
6892static void ftrace_update_trampoline(struct ftrace_ops *ops)
6893{
6894 unsigned long trampoline = ops->trampoline;
6895
6896 arch_ftrace_update_trampoline(ops);
6897 if (ops->trampoline && ops->trampoline != trampoline &&
6898 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6899 /* Add to kallsyms before the perf events */
6900 ftrace_add_trampoline_to_kallsyms(ops);
6901 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6902 ops->trampoline, ops->trampoline_size, false,
6903 FTRACE_TRAMPOLINE_SYM);
6904 /*
6905 * Record the perf text poke event after the ksymbol register
6906 * event.
6907 */
6908 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6909 (void *)ops->trampoline,
6910 ops->trampoline_size);
6911 }
6912}
6913
6914void ftrace_init_trace_array(struct trace_array *tr)
6915{
6916 INIT_LIST_HEAD(&tr->func_probes);
6917 INIT_LIST_HEAD(&tr->mod_trace);
6918 INIT_LIST_HEAD(&tr->mod_notrace);
6919}
6920#else
6921
6922struct ftrace_ops global_ops = {
6923 .func = ftrace_stub,
6924 .flags = FTRACE_OPS_FL_INITIALIZED |
6925 FTRACE_OPS_FL_PID,
6926};
6927
6928static int __init ftrace_nodyn_init(void)
6929{
6930 ftrace_enabled = 1;
6931 return 0;
6932}
6933core_initcall(ftrace_nodyn_init);
6934
6935static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6936static inline void ftrace_startup_enable(int command) { }
6937static inline void ftrace_startup_all(int command) { }
6938
6939# define ftrace_startup_sysctl() do { } while (0)
6940# define ftrace_shutdown_sysctl() do { } while (0)
6941
6942static void ftrace_update_trampoline(struct ftrace_ops *ops)
6943{
6944}
6945
6946#endif /* CONFIG_DYNAMIC_FTRACE */
6947
6948__init void ftrace_init_global_array_ops(struct trace_array *tr)
6949{
6950 tr->ops = &global_ops;
6951 tr->ops->private = tr;
6952 ftrace_init_trace_array(tr);
6953}
6954
6955void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6956{
6957 /* If we filter on pids, update to use the pid function */
6958 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6959 if (WARN_ON(tr->ops->func != ftrace_stub))
6960 printk("ftrace ops had %pS for function\n",
6961 tr->ops->func);
6962 }
6963 tr->ops->func = func;
6964 tr->ops->private = tr;
6965}
6966
6967void ftrace_reset_array_ops(struct trace_array *tr)
6968{
6969 tr->ops->func = ftrace_stub;
6970}
6971
6972static nokprobe_inline void
6973__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6974 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
6975{
6976 struct pt_regs *regs = ftrace_get_regs(fregs);
6977 struct ftrace_ops *op;
6978 int bit;
6979
6980 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
6981 if (bit < 0)
6982 return;
6983
6984 /*
6985 * Some of the ops may be dynamically allocated,
6986 * they must be freed after a synchronize_rcu().
6987 */
6988 preempt_disable_notrace();
6989
6990 do_for_each_ftrace_op(op, ftrace_ops_list) {
6991 /* Stub functions don't need to be called nor tested */
6992 if (op->flags & FTRACE_OPS_FL_STUB)
6993 continue;
6994 /*
6995 * Check the following for each ops before calling their func:
6996 * if RCU flag is set, then rcu_is_watching() must be true
6997 * if PER_CPU is set, then ftrace_function_local_disable()
6998 * must be false
6999 * Otherwise test if the ip matches the ops filter
7000 *
7001 * If any of the above fails then the op->func() is not executed.
7002 */
7003 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7004 ftrace_ops_test(op, ip, regs)) {
7005 if (FTRACE_WARN_ON(!op->func)) {
7006 pr_warn("op=%p %pS\n", op, op);
7007 goto out;
7008 }
7009 op->func(ip, parent_ip, op, fregs);
7010 }
7011 } while_for_each_ftrace_op(op);
7012out:
7013 preempt_enable_notrace();
7014 trace_clear_recursion(bit);
7015}
7016
7017/*
7018 * Some archs only support passing ip and parent_ip. Even though
7019 * the list function ignores the op parameter, we do not want any
7020 * C side effects, where a function is called without the caller
7021 * sending a third parameter.
7022 * Archs are to support both the regs and ftrace_ops at the same time.
7023 * If they support ftrace_ops, it is assumed they support regs.
7024 * If call backs want to use regs, they must either check for regs
7025 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7026 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7027 * An architecture can pass partial regs with ftrace_ops and still
7028 * set the ARCH_SUPPORTS_FTRACE_OPS.
7029 */
7030#if ARCH_SUPPORTS_FTRACE_OPS
7031static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7032 struct ftrace_ops *op, struct ftrace_regs *fregs)
7033{
7034 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7035}
7036NOKPROBE_SYMBOL(ftrace_ops_list_func);
7037#else
7038static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
7039{
7040 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7041}
7042NOKPROBE_SYMBOL(ftrace_ops_no_ops);
7043#endif
7044
7045/*
7046 * If there's only one function registered but it does not support
7047 * recursion, needs RCU protection and/or requires per cpu handling, then
7048 * this function will be called by the mcount trampoline.
7049 */
7050static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7051 struct ftrace_ops *op, struct ftrace_regs *fregs)
7052{
7053 int bit;
7054
7055 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7056 if (bit < 0)
7057 return;
7058
7059 preempt_disable_notrace();
7060
7061 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7062 op->func(ip, parent_ip, op, fregs);
7063
7064 preempt_enable_notrace();
7065 trace_clear_recursion(bit);
7066}
7067NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7068
7069/**
7070 * ftrace_ops_get_func - get the function a trampoline should call
7071 * @ops: the ops to get the function for
7072 *
7073 * Normally the mcount trampoline will call the ops->func, but there
7074 * are times that it should not. For example, if the ops does not
7075 * have its own recursion protection, then it should call the
7076 * ftrace_ops_assist_func() instead.
7077 *
7078 * Returns the function that the trampoline should call for @ops.
7079 */
7080ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7081{
7082 /*
7083 * If the function does not handle recursion or needs to be RCU safe,
7084 * then we need to call the assist handler.
7085 */
7086 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7087 FTRACE_OPS_FL_RCU))
7088 return ftrace_ops_assist_func;
7089
7090 return ops->func;
7091}
7092
7093static void
7094ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7095 struct task_struct *prev, struct task_struct *next)
7096{
7097 struct trace_array *tr = data;
7098 struct trace_pid_list *pid_list;
7099 struct trace_pid_list *no_pid_list;
7100
7101 pid_list = rcu_dereference_sched(tr->function_pids);
7102 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7103
7104 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7105 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7106 FTRACE_PID_IGNORE);
7107 else
7108 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7109 next->pid);
7110}
7111
7112static void
7113ftrace_pid_follow_sched_process_fork(void *data,
7114 struct task_struct *self,
7115 struct task_struct *task)
7116{
7117 struct trace_pid_list *pid_list;
7118 struct trace_array *tr = data;
7119
7120 pid_list = rcu_dereference_sched(tr->function_pids);
7121 trace_filter_add_remove_task(pid_list, self, task);
7122
7123 pid_list = rcu_dereference_sched(tr->function_no_pids);
7124 trace_filter_add_remove_task(pid_list, self, task);
7125}
7126
7127static void
7128ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7129{
7130 struct trace_pid_list *pid_list;
7131 struct trace_array *tr = data;
7132
7133 pid_list = rcu_dereference_sched(tr->function_pids);
7134 trace_filter_add_remove_task(pid_list, NULL, task);
7135
7136 pid_list = rcu_dereference_sched(tr->function_no_pids);
7137 trace_filter_add_remove_task(pid_list, NULL, task);
7138}
7139
7140void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7141{
7142 if (enable) {
7143 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7144 tr);
7145 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7146 tr);
7147 } else {
7148 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7149 tr);
7150 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7151 tr);
7152 }
7153}
7154
7155static void clear_ftrace_pids(struct trace_array *tr, int type)
7156{
7157 struct trace_pid_list *pid_list;
7158 struct trace_pid_list *no_pid_list;
7159 int cpu;
7160
7161 pid_list = rcu_dereference_protected(tr->function_pids,
7162 lockdep_is_held(&ftrace_lock));
7163 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7164 lockdep_is_held(&ftrace_lock));
7165
7166 /* Make sure there's something to do */
7167 if (!pid_type_enabled(type, pid_list, no_pid_list))
7168 return;
7169
7170 /* See if the pids still need to be checked after this */
7171 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7172 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7173 for_each_possible_cpu(cpu)
7174 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7175 }
7176
7177 if (type & TRACE_PIDS)
7178 rcu_assign_pointer(tr->function_pids, NULL);
7179
7180 if (type & TRACE_NO_PIDS)
7181 rcu_assign_pointer(tr->function_no_pids, NULL);
7182
7183 /* Wait till all users are no longer using pid filtering */
7184 synchronize_rcu();
7185
7186 if ((type & TRACE_PIDS) && pid_list)
7187 trace_free_pid_list(pid_list);
7188
7189 if ((type & TRACE_NO_PIDS) && no_pid_list)
7190 trace_free_pid_list(no_pid_list);
7191}
7192
7193void ftrace_clear_pids(struct trace_array *tr)
7194{
7195 mutex_lock(&ftrace_lock);
7196
7197 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7198
7199 mutex_unlock(&ftrace_lock);
7200}
7201
7202static void ftrace_pid_reset(struct trace_array *tr, int type)
7203{
7204 mutex_lock(&ftrace_lock);
7205 clear_ftrace_pids(tr, type);
7206
7207 ftrace_update_pid_func();
7208 ftrace_startup_all(0);
7209
7210 mutex_unlock(&ftrace_lock);
7211}
7212
7213/* Greater than any max PID */
7214#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7215
7216static void *fpid_start(struct seq_file *m, loff_t *pos)
7217 __acquires(RCU)
7218{
7219 struct trace_pid_list *pid_list;
7220 struct trace_array *tr = m->private;
7221
7222 mutex_lock(&ftrace_lock);
7223 rcu_read_lock_sched();
7224
7225 pid_list = rcu_dereference_sched(tr->function_pids);
7226
7227 if (!pid_list)
7228 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7229
7230 return trace_pid_start(pid_list, pos);
7231}
7232
7233static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7234{
7235 struct trace_array *tr = m->private;
7236 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7237
7238 if (v == FTRACE_NO_PIDS) {
7239 (*pos)++;
7240 return NULL;
7241 }
7242 return trace_pid_next(pid_list, v, pos);
7243}
7244
7245static void fpid_stop(struct seq_file *m, void *p)
7246 __releases(RCU)
7247{
7248 rcu_read_unlock_sched();
7249 mutex_unlock(&ftrace_lock);
7250}
7251
7252static int fpid_show(struct seq_file *m, void *v)
7253{
7254 if (v == FTRACE_NO_PIDS) {
7255 seq_puts(m, "no pid\n");
7256 return 0;
7257 }
7258
7259 return trace_pid_show(m, v);
7260}
7261
7262static const struct seq_operations ftrace_pid_sops = {
7263 .start = fpid_start,
7264 .next = fpid_next,
7265 .stop = fpid_stop,
7266 .show = fpid_show,
7267};
7268
7269static void *fnpid_start(struct seq_file *m, loff_t *pos)
7270 __acquires(RCU)
7271{
7272 struct trace_pid_list *pid_list;
7273 struct trace_array *tr = m->private;
7274
7275 mutex_lock(&ftrace_lock);
7276 rcu_read_lock_sched();
7277
7278 pid_list = rcu_dereference_sched(tr->function_no_pids);
7279
7280 if (!pid_list)
7281 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7282
7283 return trace_pid_start(pid_list, pos);
7284}
7285
7286static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7287{
7288 struct trace_array *tr = m->private;
7289 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7290
7291 if (v == FTRACE_NO_PIDS) {
7292 (*pos)++;
7293 return NULL;
7294 }
7295 return trace_pid_next(pid_list, v, pos);
7296}
7297
7298static const struct seq_operations ftrace_no_pid_sops = {
7299 .start = fnpid_start,
7300 .next = fnpid_next,
7301 .stop = fpid_stop,
7302 .show = fpid_show,
7303};
7304
7305static int pid_open(struct inode *inode, struct file *file, int type)
7306{
7307 const struct seq_operations *seq_ops;
7308 struct trace_array *tr = inode->i_private;
7309 struct seq_file *m;
7310 int ret = 0;
7311
7312 ret = tracing_check_open_get_tr(tr);
7313 if (ret)
7314 return ret;
7315
7316 if ((file->f_mode & FMODE_WRITE) &&
7317 (file->f_flags & O_TRUNC))
7318 ftrace_pid_reset(tr, type);
7319
7320 switch (type) {
7321 case TRACE_PIDS:
7322 seq_ops = &ftrace_pid_sops;
7323 break;
7324 case TRACE_NO_PIDS:
7325 seq_ops = &ftrace_no_pid_sops;
7326 break;
7327 default:
7328 trace_array_put(tr);
7329 WARN_ON_ONCE(1);
7330 return -EINVAL;
7331 }
7332
7333 ret = seq_open(file, seq_ops);
7334 if (ret < 0) {
7335 trace_array_put(tr);
7336 } else {
7337 m = file->private_data;
7338 /* copy tr over to seq ops */
7339 m->private = tr;
7340 }
7341
7342 return ret;
7343}
7344
7345static int
7346ftrace_pid_open(struct inode *inode, struct file *file)
7347{
7348 return pid_open(inode, file, TRACE_PIDS);
7349}
7350
7351static int
7352ftrace_no_pid_open(struct inode *inode, struct file *file)
7353{
7354 return pid_open(inode, file, TRACE_NO_PIDS);
7355}
7356
7357static void ignore_task_cpu(void *data)
7358{
7359 struct trace_array *tr = data;
7360 struct trace_pid_list *pid_list;
7361 struct trace_pid_list *no_pid_list;
7362
7363 /*
7364 * This function is called by on_each_cpu() while the
7365 * event_mutex is held.
7366 */
7367 pid_list = rcu_dereference_protected(tr->function_pids,
7368 mutex_is_locked(&ftrace_lock));
7369 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7370 mutex_is_locked(&ftrace_lock));
7371
7372 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7373 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7374 FTRACE_PID_IGNORE);
7375 else
7376 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7377 current->pid);
7378}
7379
7380static ssize_t
7381pid_write(struct file *filp, const char __user *ubuf,
7382 size_t cnt, loff_t *ppos, int type)
7383{
7384 struct seq_file *m = filp->private_data;
7385 struct trace_array *tr = m->private;
7386 struct trace_pid_list *filtered_pids;
7387 struct trace_pid_list *other_pids;
7388 struct trace_pid_list *pid_list;
7389 ssize_t ret;
7390
7391 if (!cnt)
7392 return 0;
7393
7394 mutex_lock(&ftrace_lock);
7395
7396 switch (type) {
7397 case TRACE_PIDS:
7398 filtered_pids = rcu_dereference_protected(tr->function_pids,
7399 lockdep_is_held(&ftrace_lock));
7400 other_pids = rcu_dereference_protected(tr->function_no_pids,
7401 lockdep_is_held(&ftrace_lock));
7402 break;
7403 case TRACE_NO_PIDS:
7404 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7405 lockdep_is_held(&ftrace_lock));
7406 other_pids = rcu_dereference_protected(tr->function_pids,
7407 lockdep_is_held(&ftrace_lock));
7408 break;
7409 default:
7410 ret = -EINVAL;
7411 WARN_ON_ONCE(1);
7412 goto out;
7413 }
7414
7415 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7416 if (ret < 0)
7417 goto out;
7418
7419 switch (type) {
7420 case TRACE_PIDS:
7421 rcu_assign_pointer(tr->function_pids, pid_list);
7422 break;
7423 case TRACE_NO_PIDS:
7424 rcu_assign_pointer(tr->function_no_pids, pid_list);
7425 break;
7426 }
7427
7428
7429 if (filtered_pids) {
7430 synchronize_rcu();
7431 trace_free_pid_list(filtered_pids);
7432 } else if (pid_list && !other_pids) {
7433 /* Register a probe to set whether to ignore the tracing of a task */
7434 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7435 }
7436
7437 /*
7438 * Ignoring of pids is done at task switch. But we have to
7439 * check for those tasks that are currently running.
7440 * Always do this in case a pid was appended or removed.
7441 */
7442 on_each_cpu(ignore_task_cpu, tr, 1);
7443
7444 ftrace_update_pid_func();
7445 ftrace_startup_all(0);
7446 out:
7447 mutex_unlock(&ftrace_lock);
7448
7449 if (ret > 0)
7450 *ppos += ret;
7451
7452 return ret;
7453}
7454
7455static ssize_t
7456ftrace_pid_write(struct file *filp, const char __user *ubuf,
7457 size_t cnt, loff_t *ppos)
7458{
7459 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7460}
7461
7462static ssize_t
7463ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7464 size_t cnt, loff_t *ppos)
7465{
7466 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7467}
7468
7469static int
7470ftrace_pid_release(struct inode *inode, struct file *file)
7471{
7472 struct trace_array *tr = inode->i_private;
7473
7474 trace_array_put(tr);
7475
7476 return seq_release(inode, file);
7477}
7478
7479static const struct file_operations ftrace_pid_fops = {
7480 .open = ftrace_pid_open,
7481 .write = ftrace_pid_write,
7482 .read = seq_read,
7483 .llseek = tracing_lseek,
7484 .release = ftrace_pid_release,
7485};
7486
7487static const struct file_operations ftrace_no_pid_fops = {
7488 .open = ftrace_no_pid_open,
7489 .write = ftrace_no_pid_write,
7490 .read = seq_read,
7491 .llseek = tracing_lseek,
7492 .release = ftrace_pid_release,
7493};
7494
7495void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7496{
7497 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7498 tr, &ftrace_pid_fops);
7499 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7500 tr, &ftrace_no_pid_fops);
7501}
7502
7503void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7504 struct dentry *d_tracer)
7505{
7506 /* Only the top level directory has the dyn_tracefs and profile */
7507 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7508
7509 ftrace_init_dyn_tracefs(d_tracer);
7510 ftrace_profile_tracefs(d_tracer);
7511}
7512
7513/**
7514 * ftrace_kill - kill ftrace
7515 *
7516 * This function should be used by panic code. It stops ftrace
7517 * but in a not so nice way. If you need to simply kill ftrace
7518 * from a non-atomic section, use ftrace_kill.
7519 */
7520void ftrace_kill(void)
7521{
7522 ftrace_disabled = 1;
7523 ftrace_enabled = 0;
7524 ftrace_trace_function = ftrace_stub;
7525}
7526
7527/**
7528 * Test if ftrace is dead or not.
7529 */
7530int ftrace_is_dead(void)
7531{
7532 return ftrace_disabled;
7533}
7534
7535/**
7536 * register_ftrace_function - register a function for profiling
7537 * @ops - ops structure that holds the function for profiling.
7538 *
7539 * Register a function to be called by all functions in the
7540 * kernel.
7541 *
7542 * Note: @ops->func and all the functions it calls must be labeled
7543 * with "notrace", otherwise it will go into a
7544 * recursive loop.
7545 */
7546int register_ftrace_function(struct ftrace_ops *ops)
7547{
7548 int ret;
7549
7550 ftrace_ops_init(ops);
7551
7552 mutex_lock(&ftrace_lock);
7553
7554 ret = ftrace_startup(ops, 0);
7555
7556 mutex_unlock(&ftrace_lock);
7557
7558 return ret;
7559}
7560EXPORT_SYMBOL_GPL(register_ftrace_function);
7561
7562/**
7563 * unregister_ftrace_function - unregister a function for profiling.
7564 * @ops - ops structure that holds the function to unregister
7565 *
7566 * Unregister a function that was added to be called by ftrace profiling.
7567 */
7568int unregister_ftrace_function(struct ftrace_ops *ops)
7569{
7570 int ret;
7571
7572 mutex_lock(&ftrace_lock);
7573 ret = ftrace_shutdown(ops, 0);
7574 mutex_unlock(&ftrace_lock);
7575
7576 return ret;
7577}
7578EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7579
7580static bool is_permanent_ops_registered(void)
7581{
7582 struct ftrace_ops *op;
7583
7584 do_for_each_ftrace_op(op, ftrace_ops_list) {
7585 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7586 return true;
7587 } while_for_each_ftrace_op(op);
7588
7589 return false;
7590}
7591
7592int
7593ftrace_enable_sysctl(struct ctl_table *table, int write,
7594 void *buffer, size_t *lenp, loff_t *ppos)
7595{
7596 int ret = -ENODEV;
7597
7598 mutex_lock(&ftrace_lock);
7599
7600 if (unlikely(ftrace_disabled))
7601 goto out;
7602
7603 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7604
7605 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7606 goto out;
7607
7608 if (ftrace_enabled) {
7609
7610 /* we are starting ftrace again */
7611 if (rcu_dereference_protected(ftrace_ops_list,
7612 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7613 update_ftrace_function();
7614
7615 ftrace_startup_sysctl();
7616
7617 } else {
7618 if (is_permanent_ops_registered()) {
7619 ftrace_enabled = true;
7620 ret = -EBUSY;
7621 goto out;
7622 }
7623
7624 /* stopping ftrace calls (just send to ftrace_stub) */
7625 ftrace_trace_function = ftrace_stub;
7626
7627 ftrace_shutdown_sysctl();
7628 }
7629
7630 last_ftrace_enabled = !!ftrace_enabled;
7631 out:
7632 mutex_unlock(&ftrace_lock);
7633 return ret;
7634}