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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/*
2 * Infrastructure for profiling code inserted by 'gcc -pg'.
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code in the latency_tracer, that is:
11 *
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
14 */
15
16#include <linux/stop_machine.h>
17#include <linux/clocksource.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/suspend.h>
21#include <linux/debugfs.h>
22#include <linux/hardirq.h>
23#include <linux/kthread.h>
24#include <linux/uaccess.h>
25#include <linux/ftrace.h>
26#include <linux/sysctl.h>
27#include <linux/slab.h>
28#include <linux/ctype.h>
29#include <linux/list.h>
30#include <linux/hash.h>
31#include <linux/rcupdate.h>
32
33#include <trace/events/sched.h>
34
35#include <asm/setup.h>
36
37#include "trace_output.h"
38#include "trace_stat.h"
39
40#define FTRACE_WARN_ON(cond) \
41 ({ \
42 int ___r = cond; \
43 if (WARN_ON(___r)) \
44 ftrace_kill(); \
45 ___r; \
46 })
47
48#define FTRACE_WARN_ON_ONCE(cond) \
49 ({ \
50 int ___r = cond; \
51 if (WARN_ON_ONCE(___r)) \
52 ftrace_kill(); \
53 ___r; \
54 })
55
56/* hash bits for specific function selection */
57#define FTRACE_HASH_BITS 7
58#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
59#define FTRACE_HASH_DEFAULT_BITS 10
60#define FTRACE_HASH_MAX_BITS 12
61
62/* ftrace_enabled is a method to turn ftrace on or off */
63int ftrace_enabled __read_mostly;
64static int last_ftrace_enabled;
65
66/* Quick disabling of function tracer. */
67int function_trace_stop;
68
69/* List for set_ftrace_pid's pids. */
70LIST_HEAD(ftrace_pids);
71struct ftrace_pid {
72 struct list_head list;
73 struct pid *pid;
74};
75
76/*
77 * ftrace_disabled is set when an anomaly is discovered.
78 * ftrace_disabled is much stronger than ftrace_enabled.
79 */
80static int ftrace_disabled __read_mostly;
81
82static DEFINE_MUTEX(ftrace_lock);
83
84static struct ftrace_ops ftrace_list_end __read_mostly = {
85 .func = ftrace_stub,
86};
87
88static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
89static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
90ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
91static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
92ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
93ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
94static struct ftrace_ops global_ops;
95
96static void
97ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
98
99/*
100 * Traverse the ftrace_global_list, invoking all entries. The reason that we
101 * can use rcu_dereference_raw() is that elements removed from this list
102 * are simply leaked, so there is no need to interact with a grace-period
103 * mechanism. The rcu_dereference_raw() calls are needed to handle
104 * concurrent insertions into the ftrace_global_list.
105 *
106 * Silly Alpha and silly pointer-speculation compiler optimizations!
107 */
108static void ftrace_global_list_func(unsigned long ip,
109 unsigned long parent_ip)
110{
111 struct ftrace_ops *op;
112
113 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
114 return;
115
116 trace_recursion_set(TRACE_GLOBAL_BIT);
117 op = rcu_dereference_raw(ftrace_global_list); /*see above*/
118 while (op != &ftrace_list_end) {
119 op->func(ip, parent_ip);
120 op = rcu_dereference_raw(op->next); /*see above*/
121 };
122 trace_recursion_clear(TRACE_GLOBAL_BIT);
123}
124
125static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
126{
127 if (!test_tsk_trace_trace(current))
128 return;
129
130 ftrace_pid_function(ip, parent_ip);
131}
132
133static void set_ftrace_pid_function(ftrace_func_t func)
134{
135 /* do not set ftrace_pid_function to itself! */
136 if (func != ftrace_pid_func)
137 ftrace_pid_function = func;
138}
139
140/**
141 * clear_ftrace_function - reset the ftrace function
142 *
143 * This NULLs the ftrace function and in essence stops
144 * tracing. There may be lag
145 */
146void clear_ftrace_function(void)
147{
148 ftrace_trace_function = ftrace_stub;
149 __ftrace_trace_function = ftrace_stub;
150 __ftrace_trace_function_delay = ftrace_stub;
151 ftrace_pid_function = ftrace_stub;
152}
153
154#undef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
155#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
156/*
157 * For those archs that do not test ftrace_trace_stop in their
158 * mcount call site, we need to do it from C.
159 */
160static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
161{
162 if (function_trace_stop)
163 return;
164
165 __ftrace_trace_function(ip, parent_ip);
166}
167#endif
168
169static void update_global_ops(void)
170{
171 ftrace_func_t func;
172
173 /*
174 * If there's only one function registered, then call that
175 * function directly. Otherwise, we need to iterate over the
176 * registered callers.
177 */
178 if (ftrace_global_list == &ftrace_list_end ||
179 ftrace_global_list->next == &ftrace_list_end)
180 func = ftrace_global_list->func;
181 else
182 func = ftrace_global_list_func;
183
184 /* If we filter on pids, update to use the pid function */
185 if (!list_empty(&ftrace_pids)) {
186 set_ftrace_pid_function(func);
187 func = ftrace_pid_func;
188 }
189
190 global_ops.func = func;
191}
192
193static void update_ftrace_function(void)
194{
195 ftrace_func_t func;
196
197 update_global_ops();
198
199 /*
200 * If we are at the end of the list and this ops is
201 * not dynamic, then have the mcount trampoline call
202 * the function directly
203 */
204 if (ftrace_ops_list == &ftrace_list_end ||
205 (ftrace_ops_list->next == &ftrace_list_end &&
206 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
207 func = ftrace_ops_list->func;
208 else
209 func = ftrace_ops_list_func;
210
211#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
212 ftrace_trace_function = func;
213#else
214#ifdef CONFIG_DYNAMIC_FTRACE
215 /* do not update till all functions have been modified */
216 __ftrace_trace_function_delay = func;
217#else
218 __ftrace_trace_function = func;
219#endif
220 ftrace_trace_function = ftrace_test_stop_func;
221#endif
222}
223
224static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
225{
226 ops->next = *list;
227 /*
228 * We are entering ops into the list but another
229 * CPU might be walking that list. We need to make sure
230 * the ops->next pointer is valid before another CPU sees
231 * the ops pointer included into the list.
232 */
233 rcu_assign_pointer(*list, ops);
234}
235
236static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
237{
238 struct ftrace_ops **p;
239
240 /*
241 * If we are removing the last function, then simply point
242 * to the ftrace_stub.
243 */
244 if (*list == ops && ops->next == &ftrace_list_end) {
245 *list = &ftrace_list_end;
246 return 0;
247 }
248
249 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
250 if (*p == ops)
251 break;
252
253 if (*p != ops)
254 return -1;
255
256 *p = (*p)->next;
257 return 0;
258}
259
260static int __register_ftrace_function(struct ftrace_ops *ops)
261{
262 if (ftrace_disabled)
263 return -ENODEV;
264
265 if (FTRACE_WARN_ON(ops == &global_ops))
266 return -EINVAL;
267
268 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
269 return -EBUSY;
270
271 if (!core_kernel_data((unsigned long)ops))
272 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
273
274 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
275 int first = ftrace_global_list == &ftrace_list_end;
276 add_ftrace_ops(&ftrace_global_list, ops);
277 ops->flags |= FTRACE_OPS_FL_ENABLED;
278 if (first)
279 add_ftrace_ops(&ftrace_ops_list, &global_ops);
280 } else
281 add_ftrace_ops(&ftrace_ops_list, ops);
282
283 if (ftrace_enabled)
284 update_ftrace_function();
285
286 return 0;
287}
288
289static int __unregister_ftrace_function(struct ftrace_ops *ops)
290{
291 int ret;
292
293 if (ftrace_disabled)
294 return -ENODEV;
295
296 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
297 return -EBUSY;
298
299 if (FTRACE_WARN_ON(ops == &global_ops))
300 return -EINVAL;
301
302 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
303 ret = remove_ftrace_ops(&ftrace_global_list, ops);
304 if (!ret && ftrace_global_list == &ftrace_list_end)
305 ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
306 if (!ret)
307 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
308 } else
309 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
310
311 if (ret < 0)
312 return ret;
313
314 if (ftrace_enabled)
315 update_ftrace_function();
316
317 /*
318 * Dynamic ops may be freed, we must make sure that all
319 * callers are done before leaving this function.
320 */
321 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
322 synchronize_sched();
323
324 return 0;
325}
326
327static void ftrace_update_pid_func(void)
328{
329 /* Only do something if we are tracing something */
330 if (ftrace_trace_function == ftrace_stub)
331 return;
332
333 update_ftrace_function();
334}
335
336#ifdef CONFIG_FUNCTION_PROFILER
337struct ftrace_profile {
338 struct hlist_node node;
339 unsigned long ip;
340 unsigned long counter;
341#ifdef CONFIG_FUNCTION_GRAPH_TRACER
342 unsigned long long time;
343 unsigned long long time_squared;
344#endif
345};
346
347struct ftrace_profile_page {
348 struct ftrace_profile_page *next;
349 unsigned long index;
350 struct ftrace_profile records[];
351};
352
353struct ftrace_profile_stat {
354 atomic_t disabled;
355 struct hlist_head *hash;
356 struct ftrace_profile_page *pages;
357 struct ftrace_profile_page *start;
358 struct tracer_stat stat;
359};
360
361#define PROFILE_RECORDS_SIZE \
362 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
363
364#define PROFILES_PER_PAGE \
365 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
366
367static int ftrace_profile_bits __read_mostly;
368static int ftrace_profile_enabled __read_mostly;
369
370/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
371static DEFINE_MUTEX(ftrace_profile_lock);
372
373static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
374
375#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
376
377static void *
378function_stat_next(void *v, int idx)
379{
380 struct ftrace_profile *rec = v;
381 struct ftrace_profile_page *pg;
382
383 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
384
385 again:
386 if (idx != 0)
387 rec++;
388
389 if ((void *)rec >= (void *)&pg->records[pg->index]) {
390 pg = pg->next;
391 if (!pg)
392 return NULL;
393 rec = &pg->records[0];
394 if (!rec->counter)
395 goto again;
396 }
397
398 return rec;
399}
400
401static void *function_stat_start(struct tracer_stat *trace)
402{
403 struct ftrace_profile_stat *stat =
404 container_of(trace, struct ftrace_profile_stat, stat);
405
406 if (!stat || !stat->start)
407 return NULL;
408
409 return function_stat_next(&stat->start->records[0], 0);
410}
411
412#ifdef CONFIG_FUNCTION_GRAPH_TRACER
413/* function graph compares on total time */
414static int function_stat_cmp(void *p1, void *p2)
415{
416 struct ftrace_profile *a = p1;
417 struct ftrace_profile *b = p2;
418
419 if (a->time < b->time)
420 return -1;
421 if (a->time > b->time)
422 return 1;
423 else
424 return 0;
425}
426#else
427/* not function graph compares against hits */
428static int function_stat_cmp(void *p1, void *p2)
429{
430 struct ftrace_profile *a = p1;
431 struct ftrace_profile *b = p2;
432
433 if (a->counter < b->counter)
434 return -1;
435 if (a->counter > b->counter)
436 return 1;
437 else
438 return 0;
439}
440#endif
441
442static int function_stat_headers(struct seq_file *m)
443{
444#ifdef CONFIG_FUNCTION_GRAPH_TRACER
445 seq_printf(m, " Function "
446 "Hit Time Avg s^2\n"
447 " -------- "
448 "--- ---- --- ---\n");
449#else
450 seq_printf(m, " Function Hit\n"
451 " -------- ---\n");
452#endif
453 return 0;
454}
455
456static int function_stat_show(struct seq_file *m, void *v)
457{
458 struct ftrace_profile *rec = v;
459 char str[KSYM_SYMBOL_LEN];
460 int ret = 0;
461#ifdef CONFIG_FUNCTION_GRAPH_TRACER
462 static struct trace_seq s;
463 unsigned long long avg;
464 unsigned long long stddev;
465#endif
466 mutex_lock(&ftrace_profile_lock);
467
468 /* we raced with function_profile_reset() */
469 if (unlikely(rec->counter == 0)) {
470 ret = -EBUSY;
471 goto out;
472 }
473
474 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
475 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
476
477#ifdef CONFIG_FUNCTION_GRAPH_TRACER
478 seq_printf(m, " ");
479 avg = rec->time;
480 do_div(avg, rec->counter);
481
482 /* Sample standard deviation (s^2) */
483 if (rec->counter <= 1)
484 stddev = 0;
485 else {
486 stddev = rec->time_squared - rec->counter * avg * avg;
487 /*
488 * Divide only 1000 for ns^2 -> us^2 conversion.
489 * trace_print_graph_duration will divide 1000 again.
490 */
491 do_div(stddev, (rec->counter - 1) * 1000);
492 }
493
494 trace_seq_init(&s);
495 trace_print_graph_duration(rec->time, &s);
496 trace_seq_puts(&s, " ");
497 trace_print_graph_duration(avg, &s);
498 trace_seq_puts(&s, " ");
499 trace_print_graph_duration(stddev, &s);
500 trace_print_seq(m, &s);
501#endif
502 seq_putc(m, '\n');
503out:
504 mutex_unlock(&ftrace_profile_lock);
505
506 return ret;
507}
508
509static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
510{
511 struct ftrace_profile_page *pg;
512
513 pg = stat->pages = stat->start;
514
515 while (pg) {
516 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
517 pg->index = 0;
518 pg = pg->next;
519 }
520
521 memset(stat->hash, 0,
522 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
523}
524
525int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
526{
527 struct ftrace_profile_page *pg;
528 int functions;
529 int pages;
530 int i;
531
532 /* If we already allocated, do nothing */
533 if (stat->pages)
534 return 0;
535
536 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
537 if (!stat->pages)
538 return -ENOMEM;
539
540#ifdef CONFIG_DYNAMIC_FTRACE
541 functions = ftrace_update_tot_cnt;
542#else
543 /*
544 * We do not know the number of functions that exist because
545 * dynamic tracing is what counts them. With past experience
546 * we have around 20K functions. That should be more than enough.
547 * It is highly unlikely we will execute every function in
548 * the kernel.
549 */
550 functions = 20000;
551#endif
552
553 pg = stat->start = stat->pages;
554
555 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
556
557 for (i = 0; i < pages; i++) {
558 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
559 if (!pg->next)
560 goto out_free;
561 pg = pg->next;
562 }
563
564 return 0;
565
566 out_free:
567 pg = stat->start;
568 while (pg) {
569 unsigned long tmp = (unsigned long)pg;
570
571 pg = pg->next;
572 free_page(tmp);
573 }
574
575 free_page((unsigned long)stat->pages);
576 stat->pages = NULL;
577 stat->start = NULL;
578
579 return -ENOMEM;
580}
581
582static int ftrace_profile_init_cpu(int cpu)
583{
584 struct ftrace_profile_stat *stat;
585 int size;
586
587 stat = &per_cpu(ftrace_profile_stats, cpu);
588
589 if (stat->hash) {
590 /* If the profile is already created, simply reset it */
591 ftrace_profile_reset(stat);
592 return 0;
593 }
594
595 /*
596 * We are profiling all functions, but usually only a few thousand
597 * functions are hit. We'll make a hash of 1024 items.
598 */
599 size = FTRACE_PROFILE_HASH_SIZE;
600
601 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
602
603 if (!stat->hash)
604 return -ENOMEM;
605
606 if (!ftrace_profile_bits) {
607 size--;
608
609 for (; size; size >>= 1)
610 ftrace_profile_bits++;
611 }
612
613 /* Preallocate the function profiling pages */
614 if (ftrace_profile_pages_init(stat) < 0) {
615 kfree(stat->hash);
616 stat->hash = NULL;
617 return -ENOMEM;
618 }
619
620 return 0;
621}
622
623static int ftrace_profile_init(void)
624{
625 int cpu;
626 int ret = 0;
627
628 for_each_online_cpu(cpu) {
629 ret = ftrace_profile_init_cpu(cpu);
630 if (ret)
631 break;
632 }
633
634 return ret;
635}
636
637/* interrupts must be disabled */
638static struct ftrace_profile *
639ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
640{
641 struct ftrace_profile *rec;
642 struct hlist_head *hhd;
643 struct hlist_node *n;
644 unsigned long key;
645
646 key = hash_long(ip, ftrace_profile_bits);
647 hhd = &stat->hash[key];
648
649 if (hlist_empty(hhd))
650 return NULL;
651
652 hlist_for_each_entry_rcu(rec, n, hhd, node) {
653 if (rec->ip == ip)
654 return rec;
655 }
656
657 return NULL;
658}
659
660static void ftrace_add_profile(struct ftrace_profile_stat *stat,
661 struct ftrace_profile *rec)
662{
663 unsigned long key;
664
665 key = hash_long(rec->ip, ftrace_profile_bits);
666 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
667}
668
669/*
670 * The memory is already allocated, this simply finds a new record to use.
671 */
672static struct ftrace_profile *
673ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
674{
675 struct ftrace_profile *rec = NULL;
676
677 /* prevent recursion (from NMIs) */
678 if (atomic_inc_return(&stat->disabled) != 1)
679 goto out;
680
681 /*
682 * Try to find the function again since an NMI
683 * could have added it
684 */
685 rec = ftrace_find_profiled_func(stat, ip);
686 if (rec)
687 goto out;
688
689 if (stat->pages->index == PROFILES_PER_PAGE) {
690 if (!stat->pages->next)
691 goto out;
692 stat->pages = stat->pages->next;
693 }
694
695 rec = &stat->pages->records[stat->pages->index++];
696 rec->ip = ip;
697 ftrace_add_profile(stat, rec);
698
699 out:
700 atomic_dec(&stat->disabled);
701
702 return rec;
703}
704
705static void
706function_profile_call(unsigned long ip, unsigned long parent_ip)
707{
708 struct ftrace_profile_stat *stat;
709 struct ftrace_profile *rec;
710 unsigned long flags;
711
712 if (!ftrace_profile_enabled)
713 return;
714
715 local_irq_save(flags);
716
717 stat = &__get_cpu_var(ftrace_profile_stats);
718 if (!stat->hash || !ftrace_profile_enabled)
719 goto out;
720
721 rec = ftrace_find_profiled_func(stat, ip);
722 if (!rec) {
723 rec = ftrace_profile_alloc(stat, ip);
724 if (!rec)
725 goto out;
726 }
727
728 rec->counter++;
729 out:
730 local_irq_restore(flags);
731}
732
733#ifdef CONFIG_FUNCTION_GRAPH_TRACER
734static int profile_graph_entry(struct ftrace_graph_ent *trace)
735{
736 function_profile_call(trace->func, 0);
737 return 1;
738}
739
740static void profile_graph_return(struct ftrace_graph_ret *trace)
741{
742 struct ftrace_profile_stat *stat;
743 unsigned long long calltime;
744 struct ftrace_profile *rec;
745 unsigned long flags;
746
747 local_irq_save(flags);
748 stat = &__get_cpu_var(ftrace_profile_stats);
749 if (!stat->hash || !ftrace_profile_enabled)
750 goto out;
751
752 /* If the calltime was zero'd ignore it */
753 if (!trace->calltime)
754 goto out;
755
756 calltime = trace->rettime - trace->calltime;
757
758 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
759 int index;
760
761 index = trace->depth;
762
763 /* Append this call time to the parent time to subtract */
764 if (index)
765 current->ret_stack[index - 1].subtime += calltime;
766
767 if (current->ret_stack[index].subtime < calltime)
768 calltime -= current->ret_stack[index].subtime;
769 else
770 calltime = 0;
771 }
772
773 rec = ftrace_find_profiled_func(stat, trace->func);
774 if (rec) {
775 rec->time += calltime;
776 rec->time_squared += calltime * calltime;
777 }
778
779 out:
780 local_irq_restore(flags);
781}
782
783static int register_ftrace_profiler(void)
784{
785 return register_ftrace_graph(&profile_graph_return,
786 &profile_graph_entry);
787}
788
789static void unregister_ftrace_profiler(void)
790{
791 unregister_ftrace_graph();
792}
793#else
794static struct ftrace_ops ftrace_profile_ops __read_mostly = {
795 .func = function_profile_call,
796};
797
798static int register_ftrace_profiler(void)
799{
800 return register_ftrace_function(&ftrace_profile_ops);
801}
802
803static void unregister_ftrace_profiler(void)
804{
805 unregister_ftrace_function(&ftrace_profile_ops);
806}
807#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
808
809static ssize_t
810ftrace_profile_write(struct file *filp, const char __user *ubuf,
811 size_t cnt, loff_t *ppos)
812{
813 unsigned long val;
814 int ret;
815
816 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
817 if (ret)
818 return ret;
819
820 val = !!val;
821
822 mutex_lock(&ftrace_profile_lock);
823 if (ftrace_profile_enabled ^ val) {
824 if (val) {
825 ret = ftrace_profile_init();
826 if (ret < 0) {
827 cnt = ret;
828 goto out;
829 }
830
831 ret = register_ftrace_profiler();
832 if (ret < 0) {
833 cnt = ret;
834 goto out;
835 }
836 ftrace_profile_enabled = 1;
837 } else {
838 ftrace_profile_enabled = 0;
839 /*
840 * unregister_ftrace_profiler calls stop_machine
841 * so this acts like an synchronize_sched.
842 */
843 unregister_ftrace_profiler();
844 }
845 }
846 out:
847 mutex_unlock(&ftrace_profile_lock);
848
849 *ppos += cnt;
850
851 return cnt;
852}
853
854static ssize_t
855ftrace_profile_read(struct file *filp, char __user *ubuf,
856 size_t cnt, loff_t *ppos)
857{
858 char buf[64]; /* big enough to hold a number */
859 int r;
860
861 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
862 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
863}
864
865static const struct file_operations ftrace_profile_fops = {
866 .open = tracing_open_generic,
867 .read = ftrace_profile_read,
868 .write = ftrace_profile_write,
869 .llseek = default_llseek,
870};
871
872/* used to initialize the real stat files */
873static struct tracer_stat function_stats __initdata = {
874 .name = "functions",
875 .stat_start = function_stat_start,
876 .stat_next = function_stat_next,
877 .stat_cmp = function_stat_cmp,
878 .stat_headers = function_stat_headers,
879 .stat_show = function_stat_show
880};
881
882static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
883{
884 struct ftrace_profile_stat *stat;
885 struct dentry *entry;
886 char *name;
887 int ret;
888 int cpu;
889
890 for_each_possible_cpu(cpu) {
891 stat = &per_cpu(ftrace_profile_stats, cpu);
892
893 /* allocate enough for function name + cpu number */
894 name = kmalloc(32, GFP_KERNEL);
895 if (!name) {
896 /*
897 * The files created are permanent, if something happens
898 * we still do not free memory.
899 */
900 WARN(1,
901 "Could not allocate stat file for cpu %d\n",
902 cpu);
903 return;
904 }
905 stat->stat = function_stats;
906 snprintf(name, 32, "function%d", cpu);
907 stat->stat.name = name;
908 ret = register_stat_tracer(&stat->stat);
909 if (ret) {
910 WARN(1,
911 "Could not register function stat for cpu %d\n",
912 cpu);
913 kfree(name);
914 return;
915 }
916 }
917
918 entry = debugfs_create_file("function_profile_enabled", 0644,
919 d_tracer, NULL, &ftrace_profile_fops);
920 if (!entry)
921 pr_warning("Could not create debugfs "
922 "'function_profile_enabled' entry\n");
923}
924
925#else /* CONFIG_FUNCTION_PROFILER */
926static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
927{
928}
929#endif /* CONFIG_FUNCTION_PROFILER */
930
931static struct pid * const ftrace_swapper_pid = &init_struct_pid;
932
933#ifdef CONFIG_DYNAMIC_FTRACE
934
935#ifndef CONFIG_FTRACE_MCOUNT_RECORD
936# error Dynamic ftrace depends on MCOUNT_RECORD
937#endif
938
939static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
940
941struct ftrace_func_probe {
942 struct hlist_node node;
943 struct ftrace_probe_ops *ops;
944 unsigned long flags;
945 unsigned long ip;
946 void *data;
947 struct rcu_head rcu;
948};
949
950enum {
951 FTRACE_ENABLE_CALLS = (1 << 0),
952 FTRACE_DISABLE_CALLS = (1 << 1),
953 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
954 FTRACE_START_FUNC_RET = (1 << 3),
955 FTRACE_STOP_FUNC_RET = (1 << 4),
956};
957struct ftrace_func_entry {
958 struct hlist_node hlist;
959 unsigned long ip;
960};
961
962struct ftrace_hash {
963 unsigned long size_bits;
964 struct hlist_head *buckets;
965 unsigned long count;
966 struct rcu_head rcu;
967};
968
969/*
970 * We make these constant because no one should touch them,
971 * but they are used as the default "empty hash", to avoid allocating
972 * it all the time. These are in a read only section such that if
973 * anyone does try to modify it, it will cause an exception.
974 */
975static const struct hlist_head empty_buckets[1];
976static const struct ftrace_hash empty_hash = {
977 .buckets = (struct hlist_head *)empty_buckets,
978};
979#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
980
981static struct ftrace_ops global_ops = {
982 .func = ftrace_stub,
983 .notrace_hash = EMPTY_HASH,
984 .filter_hash = EMPTY_HASH,
985};
986
987static struct dyn_ftrace *ftrace_new_addrs;
988
989static DEFINE_MUTEX(ftrace_regex_lock);
990
991struct ftrace_page {
992 struct ftrace_page *next;
993 int index;
994 struct dyn_ftrace records[];
995};
996
997#define ENTRIES_PER_PAGE \
998 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
999
1000/* estimate from running different kernels */
1001#define NR_TO_INIT 10000
1002
1003static struct ftrace_page *ftrace_pages_start;
1004static struct ftrace_page *ftrace_pages;
1005
1006static struct dyn_ftrace *ftrace_free_records;
1007
1008static struct ftrace_func_entry *
1009ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1010{
1011 unsigned long key;
1012 struct ftrace_func_entry *entry;
1013 struct hlist_head *hhd;
1014 struct hlist_node *n;
1015
1016 if (!hash->count)
1017 return NULL;
1018
1019 if (hash->size_bits > 0)
1020 key = hash_long(ip, hash->size_bits);
1021 else
1022 key = 0;
1023
1024 hhd = &hash->buckets[key];
1025
1026 hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1027 if (entry->ip == ip)
1028 return entry;
1029 }
1030 return NULL;
1031}
1032
1033static void __add_hash_entry(struct ftrace_hash *hash,
1034 struct ftrace_func_entry *entry)
1035{
1036 struct hlist_head *hhd;
1037 unsigned long key;
1038
1039 if (hash->size_bits)
1040 key = hash_long(entry->ip, hash->size_bits);
1041 else
1042 key = 0;
1043
1044 hhd = &hash->buckets[key];
1045 hlist_add_head(&entry->hlist, hhd);
1046 hash->count++;
1047}
1048
1049static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1050{
1051 struct ftrace_func_entry *entry;
1052
1053 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1054 if (!entry)
1055 return -ENOMEM;
1056
1057 entry->ip = ip;
1058 __add_hash_entry(hash, entry);
1059
1060 return 0;
1061}
1062
1063static void
1064free_hash_entry(struct ftrace_hash *hash,
1065 struct ftrace_func_entry *entry)
1066{
1067 hlist_del(&entry->hlist);
1068 kfree(entry);
1069 hash->count--;
1070}
1071
1072static void
1073remove_hash_entry(struct ftrace_hash *hash,
1074 struct ftrace_func_entry *entry)
1075{
1076 hlist_del(&entry->hlist);
1077 hash->count--;
1078}
1079
1080static void ftrace_hash_clear(struct ftrace_hash *hash)
1081{
1082 struct hlist_head *hhd;
1083 struct hlist_node *tp, *tn;
1084 struct ftrace_func_entry *entry;
1085 int size = 1 << hash->size_bits;
1086 int i;
1087
1088 if (!hash->count)
1089 return;
1090
1091 for (i = 0; i < size; i++) {
1092 hhd = &hash->buckets[i];
1093 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1094 free_hash_entry(hash, entry);
1095 }
1096 FTRACE_WARN_ON(hash->count);
1097}
1098
1099static void free_ftrace_hash(struct ftrace_hash *hash)
1100{
1101 if (!hash || hash == EMPTY_HASH)
1102 return;
1103 ftrace_hash_clear(hash);
1104 kfree(hash->buckets);
1105 kfree(hash);
1106}
1107
1108static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1109{
1110 struct ftrace_hash *hash;
1111
1112 hash = container_of(rcu, struct ftrace_hash, rcu);
1113 free_ftrace_hash(hash);
1114}
1115
1116static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1117{
1118 if (!hash || hash == EMPTY_HASH)
1119 return;
1120 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1121}
1122
1123static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1124{
1125 struct ftrace_hash *hash;
1126 int size;
1127
1128 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1129 if (!hash)
1130 return NULL;
1131
1132 size = 1 << size_bits;
1133 hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1134
1135 if (!hash->buckets) {
1136 kfree(hash);
1137 return NULL;
1138 }
1139
1140 hash->size_bits = size_bits;
1141
1142 return hash;
1143}
1144
1145static struct ftrace_hash *
1146alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1147{
1148 struct ftrace_func_entry *entry;
1149 struct ftrace_hash *new_hash;
1150 struct hlist_node *tp;
1151 int size;
1152 int ret;
1153 int i;
1154
1155 new_hash = alloc_ftrace_hash(size_bits);
1156 if (!new_hash)
1157 return NULL;
1158
1159 /* Empty hash? */
1160 if (!hash || !hash->count)
1161 return new_hash;
1162
1163 size = 1 << hash->size_bits;
1164 for (i = 0; i < size; i++) {
1165 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1166 ret = add_hash_entry(new_hash, entry->ip);
1167 if (ret < 0)
1168 goto free_hash;
1169 }
1170 }
1171
1172 FTRACE_WARN_ON(new_hash->count != hash->count);
1173
1174 return new_hash;
1175
1176 free_hash:
1177 free_ftrace_hash(new_hash);
1178 return NULL;
1179}
1180
1181static void
1182ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1183static void
1184ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1185
1186static int
1187ftrace_hash_move(struct ftrace_ops *ops, int enable,
1188 struct ftrace_hash **dst, struct ftrace_hash *src)
1189{
1190 struct ftrace_func_entry *entry;
1191 struct hlist_node *tp, *tn;
1192 struct hlist_head *hhd;
1193 struct ftrace_hash *old_hash;
1194 struct ftrace_hash *new_hash;
1195 unsigned long key;
1196 int size = src->count;
1197 int bits = 0;
1198 int ret;
1199 int i;
1200
1201 /*
1202 * Remove the current set, update the hash and add
1203 * them back.
1204 */
1205 ftrace_hash_rec_disable(ops, enable);
1206
1207 /*
1208 * If the new source is empty, just free dst and assign it
1209 * the empty_hash.
1210 */
1211 if (!src->count) {
1212 free_ftrace_hash_rcu(*dst);
1213 rcu_assign_pointer(*dst, EMPTY_HASH);
1214 return 0;
1215 }
1216
1217 /*
1218 * Make the hash size about 1/2 the # found
1219 */
1220 for (size /= 2; size; size >>= 1)
1221 bits++;
1222
1223 /* Don't allocate too much */
1224 if (bits > FTRACE_HASH_MAX_BITS)
1225 bits = FTRACE_HASH_MAX_BITS;
1226
1227 ret = -ENOMEM;
1228 new_hash = alloc_ftrace_hash(bits);
1229 if (!new_hash)
1230 goto out;
1231
1232 size = 1 << src->size_bits;
1233 for (i = 0; i < size; i++) {
1234 hhd = &src->buckets[i];
1235 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1236 if (bits > 0)
1237 key = hash_long(entry->ip, bits);
1238 else
1239 key = 0;
1240 remove_hash_entry(src, entry);
1241 __add_hash_entry(new_hash, entry);
1242 }
1243 }
1244
1245 old_hash = *dst;
1246 rcu_assign_pointer(*dst, new_hash);
1247 free_ftrace_hash_rcu(old_hash);
1248
1249 ret = 0;
1250 out:
1251 /*
1252 * Enable regardless of ret:
1253 * On success, we enable the new hash.
1254 * On failure, we re-enable the original hash.
1255 */
1256 ftrace_hash_rec_enable(ops, enable);
1257
1258 return ret;
1259}
1260
1261/*
1262 * Test the hashes for this ops to see if we want to call
1263 * the ops->func or not.
1264 *
1265 * It's a match if the ip is in the ops->filter_hash or
1266 * the filter_hash does not exist or is empty,
1267 * AND
1268 * the ip is not in the ops->notrace_hash.
1269 *
1270 * This needs to be called with preemption disabled as
1271 * the hashes are freed with call_rcu_sched().
1272 */
1273static int
1274ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1275{
1276 struct ftrace_hash *filter_hash;
1277 struct ftrace_hash *notrace_hash;
1278 int ret;
1279
1280 filter_hash = rcu_dereference_raw(ops->filter_hash);
1281 notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1282
1283 if ((!filter_hash || !filter_hash->count ||
1284 ftrace_lookup_ip(filter_hash, ip)) &&
1285 (!notrace_hash || !notrace_hash->count ||
1286 !ftrace_lookup_ip(notrace_hash, ip)))
1287 ret = 1;
1288 else
1289 ret = 0;
1290
1291 return ret;
1292}
1293
1294/*
1295 * This is a double for. Do not use 'break' to break out of the loop,
1296 * you must use a goto.
1297 */
1298#define do_for_each_ftrace_rec(pg, rec) \
1299 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1300 int _____i; \
1301 for (_____i = 0; _____i < pg->index; _____i++) { \
1302 rec = &pg->records[_____i];
1303
1304#define while_for_each_ftrace_rec() \
1305 } \
1306 }
1307
1308static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1309 int filter_hash,
1310 bool inc)
1311{
1312 struct ftrace_hash *hash;
1313 struct ftrace_hash *other_hash;
1314 struct ftrace_page *pg;
1315 struct dyn_ftrace *rec;
1316 int count = 0;
1317 int all = 0;
1318
1319 /* Only update if the ops has been registered */
1320 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1321 return;
1322
1323 /*
1324 * In the filter_hash case:
1325 * If the count is zero, we update all records.
1326 * Otherwise we just update the items in the hash.
1327 *
1328 * In the notrace_hash case:
1329 * We enable the update in the hash.
1330 * As disabling notrace means enabling the tracing,
1331 * and enabling notrace means disabling, the inc variable
1332 * gets inversed.
1333 */
1334 if (filter_hash) {
1335 hash = ops->filter_hash;
1336 other_hash = ops->notrace_hash;
1337 if (!hash || !hash->count)
1338 all = 1;
1339 } else {
1340 inc = !inc;
1341 hash = ops->notrace_hash;
1342 other_hash = ops->filter_hash;
1343 /*
1344 * If the notrace hash has no items,
1345 * then there's nothing to do.
1346 */
1347 if (hash && !hash->count)
1348 return;
1349 }
1350
1351 do_for_each_ftrace_rec(pg, rec) {
1352 int in_other_hash = 0;
1353 int in_hash = 0;
1354 int match = 0;
1355
1356 if (all) {
1357 /*
1358 * Only the filter_hash affects all records.
1359 * Update if the record is not in the notrace hash.
1360 */
1361 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1362 match = 1;
1363 } else {
1364 in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1365 in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1366
1367 /*
1368 *
1369 */
1370 if (filter_hash && in_hash && !in_other_hash)
1371 match = 1;
1372 else if (!filter_hash && in_hash &&
1373 (in_other_hash || !other_hash->count))
1374 match = 1;
1375 }
1376 if (!match)
1377 continue;
1378
1379 if (inc) {
1380 rec->flags++;
1381 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1382 return;
1383 } else {
1384 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1385 return;
1386 rec->flags--;
1387 }
1388 count++;
1389 /* Shortcut, if we handled all records, we are done. */
1390 if (!all && count == hash->count)
1391 return;
1392 } while_for_each_ftrace_rec();
1393}
1394
1395static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1396 int filter_hash)
1397{
1398 __ftrace_hash_rec_update(ops, filter_hash, 0);
1399}
1400
1401static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1402 int filter_hash)
1403{
1404 __ftrace_hash_rec_update(ops, filter_hash, 1);
1405}
1406
1407static void ftrace_free_rec(struct dyn_ftrace *rec)
1408{
1409 rec->freelist = ftrace_free_records;
1410 ftrace_free_records = rec;
1411 rec->flags |= FTRACE_FL_FREE;
1412}
1413
1414static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1415{
1416 struct dyn_ftrace *rec;
1417
1418 /* First check for freed records */
1419 if (ftrace_free_records) {
1420 rec = ftrace_free_records;
1421
1422 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
1423 FTRACE_WARN_ON_ONCE(1);
1424 ftrace_free_records = NULL;
1425 return NULL;
1426 }
1427
1428 ftrace_free_records = rec->freelist;
1429 memset(rec, 0, sizeof(*rec));
1430 return rec;
1431 }
1432
1433 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
1434 if (!ftrace_pages->next) {
1435 /* allocate another page */
1436 ftrace_pages->next =
1437 (void *)get_zeroed_page(GFP_KERNEL);
1438 if (!ftrace_pages->next)
1439 return NULL;
1440 }
1441 ftrace_pages = ftrace_pages->next;
1442 }
1443
1444 return &ftrace_pages->records[ftrace_pages->index++];
1445}
1446
1447static struct dyn_ftrace *
1448ftrace_record_ip(unsigned long ip)
1449{
1450 struct dyn_ftrace *rec;
1451
1452 if (ftrace_disabled)
1453 return NULL;
1454
1455 rec = ftrace_alloc_dyn_node(ip);
1456 if (!rec)
1457 return NULL;
1458
1459 rec->ip = ip;
1460 rec->newlist = ftrace_new_addrs;
1461 ftrace_new_addrs = rec;
1462
1463 return rec;
1464}
1465
1466static void print_ip_ins(const char *fmt, unsigned char *p)
1467{
1468 int i;
1469
1470 printk(KERN_CONT "%s", fmt);
1471
1472 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1473 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1474}
1475
1476static void ftrace_bug(int failed, unsigned long ip)
1477{
1478 switch (failed) {
1479 case -EFAULT:
1480 FTRACE_WARN_ON_ONCE(1);
1481 pr_info("ftrace faulted on modifying ");
1482 print_ip_sym(ip);
1483 break;
1484 case -EINVAL:
1485 FTRACE_WARN_ON_ONCE(1);
1486 pr_info("ftrace failed to modify ");
1487 print_ip_sym(ip);
1488 print_ip_ins(" actual: ", (unsigned char *)ip);
1489 printk(KERN_CONT "\n");
1490 break;
1491 case -EPERM:
1492 FTRACE_WARN_ON_ONCE(1);
1493 pr_info("ftrace faulted on writing ");
1494 print_ip_sym(ip);
1495 break;
1496 default:
1497 FTRACE_WARN_ON_ONCE(1);
1498 pr_info("ftrace faulted on unknown error ");
1499 print_ip_sym(ip);
1500 }
1501}
1502
1503
1504/* Return 1 if the address range is reserved for ftrace */
1505int ftrace_text_reserved(void *start, void *end)
1506{
1507 struct dyn_ftrace *rec;
1508 struct ftrace_page *pg;
1509
1510 do_for_each_ftrace_rec(pg, rec) {
1511 if (rec->ip <= (unsigned long)end &&
1512 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1513 return 1;
1514 } while_for_each_ftrace_rec();
1515 return 0;
1516}
1517
1518
1519static int
1520__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1521{
1522 unsigned long ftrace_addr;
1523 unsigned long flag = 0UL;
1524
1525 ftrace_addr = (unsigned long)FTRACE_ADDR;
1526
1527 /*
1528 * If we are enabling tracing:
1529 *
1530 * If the record has a ref count, then we need to enable it
1531 * because someone is using it.
1532 *
1533 * Otherwise we make sure its disabled.
1534 *
1535 * If we are disabling tracing, then disable all records that
1536 * are enabled.
1537 */
1538 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1539 flag = FTRACE_FL_ENABLED;
1540
1541 /* If the state of this record hasn't changed, then do nothing */
1542 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1543 return 0;
1544
1545 if (flag) {
1546 rec->flags |= FTRACE_FL_ENABLED;
1547 return ftrace_make_call(rec, ftrace_addr);
1548 }
1549
1550 rec->flags &= ~FTRACE_FL_ENABLED;
1551 return ftrace_make_nop(NULL, rec, ftrace_addr);
1552}
1553
1554static void ftrace_replace_code(int enable)
1555{
1556 struct dyn_ftrace *rec;
1557 struct ftrace_page *pg;
1558 int failed;
1559
1560 if (unlikely(ftrace_disabled))
1561 return;
1562
1563 do_for_each_ftrace_rec(pg, rec) {
1564 /* Skip over free records */
1565 if (rec->flags & FTRACE_FL_FREE)
1566 continue;
1567
1568 failed = __ftrace_replace_code(rec, enable);
1569 if (failed) {
1570 ftrace_bug(failed, rec->ip);
1571 /* Stop processing */
1572 return;
1573 }
1574 } while_for_each_ftrace_rec();
1575}
1576
1577static int
1578ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1579{
1580 unsigned long ip;
1581 int ret;
1582
1583 ip = rec->ip;
1584
1585 if (unlikely(ftrace_disabled))
1586 return 0;
1587
1588 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1589 if (ret) {
1590 ftrace_bug(ret, ip);
1591 return 0;
1592 }
1593 return 1;
1594}
1595
1596/*
1597 * archs can override this function if they must do something
1598 * before the modifying code is performed.
1599 */
1600int __weak ftrace_arch_code_modify_prepare(void)
1601{
1602 return 0;
1603}
1604
1605/*
1606 * archs can override this function if they must do something
1607 * after the modifying code is performed.
1608 */
1609int __weak ftrace_arch_code_modify_post_process(void)
1610{
1611 return 0;
1612}
1613
1614static int __ftrace_modify_code(void *data)
1615{
1616 int *command = data;
1617
1618 /*
1619 * Do not call function tracer while we update the code.
1620 * We are in stop machine, no worrying about races.
1621 */
1622 function_trace_stop++;
1623
1624 if (*command & FTRACE_ENABLE_CALLS)
1625 ftrace_replace_code(1);
1626 else if (*command & FTRACE_DISABLE_CALLS)
1627 ftrace_replace_code(0);
1628
1629 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1630 ftrace_update_ftrace_func(ftrace_trace_function);
1631
1632 if (*command & FTRACE_START_FUNC_RET)
1633 ftrace_enable_ftrace_graph_caller();
1634 else if (*command & FTRACE_STOP_FUNC_RET)
1635 ftrace_disable_ftrace_graph_caller();
1636
1637#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1638 /*
1639 * For archs that call ftrace_test_stop_func(), we must
1640 * wait till after we update all the function callers
1641 * before we update the callback. This keeps different
1642 * ops that record different functions from corrupting
1643 * each other.
1644 */
1645 __ftrace_trace_function = __ftrace_trace_function_delay;
1646#endif
1647 function_trace_stop--;
1648
1649 return 0;
1650}
1651
1652static void ftrace_run_update_code(int command)
1653{
1654 int ret;
1655
1656 ret = ftrace_arch_code_modify_prepare();
1657 FTRACE_WARN_ON(ret);
1658 if (ret)
1659 return;
1660
1661 stop_machine(__ftrace_modify_code, &command, NULL);
1662
1663 ret = ftrace_arch_code_modify_post_process();
1664 FTRACE_WARN_ON(ret);
1665}
1666
1667static ftrace_func_t saved_ftrace_func;
1668static int ftrace_start_up;
1669static int global_start_up;
1670
1671static void ftrace_startup_enable(int command)
1672{
1673 if (saved_ftrace_func != ftrace_trace_function) {
1674 saved_ftrace_func = ftrace_trace_function;
1675 command |= FTRACE_UPDATE_TRACE_FUNC;
1676 }
1677
1678 if (!command || !ftrace_enabled)
1679 return;
1680
1681 ftrace_run_update_code(command);
1682}
1683
1684static int ftrace_startup(struct ftrace_ops *ops, int command)
1685{
1686 bool hash_enable = true;
1687
1688 if (unlikely(ftrace_disabled))
1689 return -ENODEV;
1690
1691 ftrace_start_up++;
1692 command |= FTRACE_ENABLE_CALLS;
1693
1694 /* ops marked global share the filter hashes */
1695 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1696 ops = &global_ops;
1697 /* Don't update hash if global is already set */
1698 if (global_start_up)
1699 hash_enable = false;
1700 global_start_up++;
1701 }
1702
1703 ops->flags |= FTRACE_OPS_FL_ENABLED;
1704 if (hash_enable)
1705 ftrace_hash_rec_enable(ops, 1);
1706
1707 ftrace_startup_enable(command);
1708
1709 return 0;
1710}
1711
1712static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1713{
1714 bool hash_disable = true;
1715
1716 if (unlikely(ftrace_disabled))
1717 return;
1718
1719 ftrace_start_up--;
1720 /*
1721 * Just warn in case of unbalance, no need to kill ftrace, it's not
1722 * critical but the ftrace_call callers may be never nopped again after
1723 * further ftrace uses.
1724 */
1725 WARN_ON_ONCE(ftrace_start_up < 0);
1726
1727 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1728 ops = &global_ops;
1729 global_start_up--;
1730 WARN_ON_ONCE(global_start_up < 0);
1731 /* Don't update hash if global still has users */
1732 if (global_start_up) {
1733 WARN_ON_ONCE(!ftrace_start_up);
1734 hash_disable = false;
1735 }
1736 }
1737
1738 if (hash_disable)
1739 ftrace_hash_rec_disable(ops, 1);
1740
1741 if (ops != &global_ops || !global_start_up)
1742 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1743
1744 if (!ftrace_start_up)
1745 command |= FTRACE_DISABLE_CALLS;
1746
1747 if (saved_ftrace_func != ftrace_trace_function) {
1748 saved_ftrace_func = ftrace_trace_function;
1749 command |= FTRACE_UPDATE_TRACE_FUNC;
1750 }
1751
1752 if (!command || !ftrace_enabled)
1753 return;
1754
1755 ftrace_run_update_code(command);
1756}
1757
1758static void ftrace_startup_sysctl(void)
1759{
1760 if (unlikely(ftrace_disabled))
1761 return;
1762
1763 /* Force update next time */
1764 saved_ftrace_func = NULL;
1765 /* ftrace_start_up is true if we want ftrace running */
1766 if (ftrace_start_up)
1767 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1768}
1769
1770static void ftrace_shutdown_sysctl(void)
1771{
1772 if (unlikely(ftrace_disabled))
1773 return;
1774
1775 /* ftrace_start_up is true if ftrace is running */
1776 if (ftrace_start_up)
1777 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1778}
1779
1780static cycle_t ftrace_update_time;
1781static unsigned long ftrace_update_cnt;
1782unsigned long ftrace_update_tot_cnt;
1783
1784static int ops_traces_mod(struct ftrace_ops *ops)
1785{
1786 struct ftrace_hash *hash;
1787
1788 hash = ops->filter_hash;
1789 return !!(!hash || !hash->count);
1790}
1791
1792static int ftrace_update_code(struct module *mod)
1793{
1794 struct dyn_ftrace *p;
1795 cycle_t start, stop;
1796 unsigned long ref = 0;
1797
1798 /*
1799 * When adding a module, we need to check if tracers are
1800 * currently enabled and if they are set to trace all functions.
1801 * If they are, we need to enable the module functions as well
1802 * as update the reference counts for those function records.
1803 */
1804 if (mod) {
1805 struct ftrace_ops *ops;
1806
1807 for (ops = ftrace_ops_list;
1808 ops != &ftrace_list_end; ops = ops->next) {
1809 if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1810 ops_traces_mod(ops))
1811 ref++;
1812 }
1813 }
1814
1815 start = ftrace_now(raw_smp_processor_id());
1816 ftrace_update_cnt = 0;
1817
1818 while (ftrace_new_addrs) {
1819
1820 /* If something went wrong, bail without enabling anything */
1821 if (unlikely(ftrace_disabled))
1822 return -1;
1823
1824 p = ftrace_new_addrs;
1825 ftrace_new_addrs = p->newlist;
1826 p->flags = ref;
1827
1828 /*
1829 * Do the initial record conversion from mcount jump
1830 * to the NOP instructions.
1831 */
1832 if (!ftrace_code_disable(mod, p)) {
1833 ftrace_free_rec(p);
1834 /* Game over */
1835 break;
1836 }
1837
1838 ftrace_update_cnt++;
1839
1840 /*
1841 * If the tracing is enabled, go ahead and enable the record.
1842 *
1843 * The reason not to enable the record immediatelly is the
1844 * inherent check of ftrace_make_nop/ftrace_make_call for
1845 * correct previous instructions. Making first the NOP
1846 * conversion puts the module to the correct state, thus
1847 * passing the ftrace_make_call check.
1848 */
1849 if (ftrace_start_up && ref) {
1850 int failed = __ftrace_replace_code(p, 1);
1851 if (failed) {
1852 ftrace_bug(failed, p->ip);
1853 ftrace_free_rec(p);
1854 }
1855 }
1856 }
1857
1858 stop = ftrace_now(raw_smp_processor_id());
1859 ftrace_update_time = stop - start;
1860 ftrace_update_tot_cnt += ftrace_update_cnt;
1861
1862 return 0;
1863}
1864
1865static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1866{
1867 struct ftrace_page *pg;
1868 int cnt;
1869 int i;
1870
1871 /* allocate a few pages */
1872 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1873 if (!ftrace_pages_start)
1874 return -1;
1875
1876 /*
1877 * Allocate a few more pages.
1878 *
1879 * TODO: have some parser search vmlinux before
1880 * final linking to find all calls to ftrace.
1881 * Then we can:
1882 * a) know how many pages to allocate.
1883 * and/or
1884 * b) set up the table then.
1885 *
1886 * The dynamic code is still necessary for
1887 * modules.
1888 */
1889
1890 pg = ftrace_pages = ftrace_pages_start;
1891
1892 cnt = num_to_init / ENTRIES_PER_PAGE;
1893 pr_info("ftrace: allocating %ld entries in %d pages\n",
1894 num_to_init, cnt + 1);
1895
1896 for (i = 0; i < cnt; i++) {
1897 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1898
1899 /* If we fail, we'll try later anyway */
1900 if (!pg->next)
1901 break;
1902
1903 pg = pg->next;
1904 }
1905
1906 return 0;
1907}
1908
1909enum {
1910 FTRACE_ITER_FILTER = (1 << 0),
1911 FTRACE_ITER_NOTRACE = (1 << 1),
1912 FTRACE_ITER_PRINTALL = (1 << 2),
1913 FTRACE_ITER_HASH = (1 << 3),
1914 FTRACE_ITER_ENABLED = (1 << 4),
1915};
1916
1917#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1918
1919struct ftrace_iterator {
1920 loff_t pos;
1921 loff_t func_pos;
1922 struct ftrace_page *pg;
1923 struct dyn_ftrace *func;
1924 struct ftrace_func_probe *probe;
1925 struct trace_parser parser;
1926 struct ftrace_hash *hash;
1927 struct ftrace_ops *ops;
1928 int hidx;
1929 int idx;
1930 unsigned flags;
1931};
1932
1933static void *
1934t_hash_next(struct seq_file *m, loff_t *pos)
1935{
1936 struct ftrace_iterator *iter = m->private;
1937 struct hlist_node *hnd = NULL;
1938 struct hlist_head *hhd;
1939
1940 (*pos)++;
1941 iter->pos = *pos;
1942
1943 if (iter->probe)
1944 hnd = &iter->probe->node;
1945 retry:
1946 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1947 return NULL;
1948
1949 hhd = &ftrace_func_hash[iter->hidx];
1950
1951 if (hlist_empty(hhd)) {
1952 iter->hidx++;
1953 hnd = NULL;
1954 goto retry;
1955 }
1956
1957 if (!hnd)
1958 hnd = hhd->first;
1959 else {
1960 hnd = hnd->next;
1961 if (!hnd) {
1962 iter->hidx++;
1963 goto retry;
1964 }
1965 }
1966
1967 if (WARN_ON_ONCE(!hnd))
1968 return NULL;
1969
1970 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1971
1972 return iter;
1973}
1974
1975static void *t_hash_start(struct seq_file *m, loff_t *pos)
1976{
1977 struct ftrace_iterator *iter = m->private;
1978 void *p = NULL;
1979 loff_t l;
1980
1981 if (iter->func_pos > *pos)
1982 return NULL;
1983
1984 iter->hidx = 0;
1985 for (l = 0; l <= (*pos - iter->func_pos); ) {
1986 p = t_hash_next(m, &l);
1987 if (!p)
1988 break;
1989 }
1990 if (!p)
1991 return NULL;
1992
1993 /* Only set this if we have an item */
1994 iter->flags |= FTRACE_ITER_HASH;
1995
1996 return iter;
1997}
1998
1999static int
2000t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2001{
2002 struct ftrace_func_probe *rec;
2003
2004 rec = iter->probe;
2005 if (WARN_ON_ONCE(!rec))
2006 return -EIO;
2007
2008 if (rec->ops->print)
2009 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2010
2011 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2012
2013 if (rec->data)
2014 seq_printf(m, ":%p", rec->data);
2015 seq_putc(m, '\n');
2016
2017 return 0;
2018}
2019
2020static void *
2021t_next(struct seq_file *m, void *v, loff_t *pos)
2022{
2023 struct ftrace_iterator *iter = m->private;
2024 struct ftrace_ops *ops = &global_ops;
2025 struct dyn_ftrace *rec = NULL;
2026
2027 if (unlikely(ftrace_disabled))
2028 return NULL;
2029
2030 if (iter->flags & FTRACE_ITER_HASH)
2031 return t_hash_next(m, pos);
2032
2033 (*pos)++;
2034 iter->pos = iter->func_pos = *pos;
2035
2036 if (iter->flags & FTRACE_ITER_PRINTALL)
2037 return t_hash_start(m, pos);
2038
2039 retry:
2040 if (iter->idx >= iter->pg->index) {
2041 if (iter->pg->next) {
2042 iter->pg = iter->pg->next;
2043 iter->idx = 0;
2044 goto retry;
2045 }
2046 } else {
2047 rec = &iter->pg->records[iter->idx++];
2048 if ((rec->flags & FTRACE_FL_FREE) ||
2049
2050 ((iter->flags & FTRACE_ITER_FILTER) &&
2051 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2052
2053 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2054 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2055
2056 ((iter->flags & FTRACE_ITER_ENABLED) &&
2057 !(rec->flags & ~FTRACE_FL_MASK))) {
2058
2059 rec = NULL;
2060 goto retry;
2061 }
2062 }
2063
2064 if (!rec)
2065 return t_hash_start(m, pos);
2066
2067 iter->func = rec;
2068
2069 return iter;
2070}
2071
2072static void reset_iter_read(struct ftrace_iterator *iter)
2073{
2074 iter->pos = 0;
2075 iter->func_pos = 0;
2076 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2077}
2078
2079static void *t_start(struct seq_file *m, loff_t *pos)
2080{
2081 struct ftrace_iterator *iter = m->private;
2082 struct ftrace_ops *ops = &global_ops;
2083 void *p = NULL;
2084 loff_t l;
2085
2086 mutex_lock(&ftrace_lock);
2087
2088 if (unlikely(ftrace_disabled))
2089 return NULL;
2090
2091 /*
2092 * If an lseek was done, then reset and start from beginning.
2093 */
2094 if (*pos < iter->pos)
2095 reset_iter_read(iter);
2096
2097 /*
2098 * For set_ftrace_filter reading, if we have the filter
2099 * off, we can short cut and just print out that all
2100 * functions are enabled.
2101 */
2102 if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
2103 if (*pos > 0)
2104 return t_hash_start(m, pos);
2105 iter->flags |= FTRACE_ITER_PRINTALL;
2106 /* reset in case of seek/pread */
2107 iter->flags &= ~FTRACE_ITER_HASH;
2108 return iter;
2109 }
2110
2111 if (iter->flags & FTRACE_ITER_HASH)
2112 return t_hash_start(m, pos);
2113
2114 /*
2115 * Unfortunately, we need to restart at ftrace_pages_start
2116 * every time we let go of the ftrace_mutex. This is because
2117 * those pointers can change without the lock.
2118 */
2119 iter->pg = ftrace_pages_start;
2120 iter->idx = 0;
2121 for (l = 0; l <= *pos; ) {
2122 p = t_next(m, p, &l);
2123 if (!p)
2124 break;
2125 }
2126
2127 if (!p) {
2128 if (iter->flags & FTRACE_ITER_FILTER)
2129 return t_hash_start(m, pos);
2130
2131 return NULL;
2132 }
2133
2134 return iter;
2135}
2136
2137static void t_stop(struct seq_file *m, void *p)
2138{
2139 mutex_unlock(&ftrace_lock);
2140}
2141
2142static int t_show(struct seq_file *m, void *v)
2143{
2144 struct ftrace_iterator *iter = m->private;
2145 struct dyn_ftrace *rec;
2146
2147 if (iter->flags & FTRACE_ITER_HASH)
2148 return t_hash_show(m, iter);
2149
2150 if (iter->flags & FTRACE_ITER_PRINTALL) {
2151 seq_printf(m, "#### all functions enabled ####\n");
2152 return 0;
2153 }
2154
2155 rec = iter->func;
2156
2157 if (!rec)
2158 return 0;
2159
2160 seq_printf(m, "%ps", (void *)rec->ip);
2161 if (iter->flags & FTRACE_ITER_ENABLED)
2162 seq_printf(m, " (%ld)",
2163 rec->flags & ~FTRACE_FL_MASK);
2164 seq_printf(m, "\n");
2165
2166 return 0;
2167}
2168
2169static const struct seq_operations show_ftrace_seq_ops = {
2170 .start = t_start,
2171 .next = t_next,
2172 .stop = t_stop,
2173 .show = t_show,
2174};
2175
2176static int
2177ftrace_avail_open(struct inode *inode, struct file *file)
2178{
2179 struct ftrace_iterator *iter;
2180 int ret;
2181
2182 if (unlikely(ftrace_disabled))
2183 return -ENODEV;
2184
2185 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2186 if (!iter)
2187 return -ENOMEM;
2188
2189 iter->pg = ftrace_pages_start;
2190
2191 ret = seq_open(file, &show_ftrace_seq_ops);
2192 if (!ret) {
2193 struct seq_file *m = file->private_data;
2194
2195 m->private = iter;
2196 } else {
2197 kfree(iter);
2198 }
2199
2200 return ret;
2201}
2202
2203static int
2204ftrace_enabled_open(struct inode *inode, struct file *file)
2205{
2206 struct ftrace_iterator *iter;
2207 int ret;
2208
2209 if (unlikely(ftrace_disabled))
2210 return -ENODEV;
2211
2212 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2213 if (!iter)
2214 return -ENOMEM;
2215
2216 iter->pg = ftrace_pages_start;
2217 iter->flags = FTRACE_ITER_ENABLED;
2218
2219 ret = seq_open(file, &show_ftrace_seq_ops);
2220 if (!ret) {
2221 struct seq_file *m = file->private_data;
2222
2223 m->private = iter;
2224 } else {
2225 kfree(iter);
2226 }
2227
2228 return ret;
2229}
2230
2231static void ftrace_filter_reset(struct ftrace_hash *hash)
2232{
2233 mutex_lock(&ftrace_lock);
2234 ftrace_hash_clear(hash);
2235 mutex_unlock(&ftrace_lock);
2236}
2237
2238static int
2239ftrace_regex_open(struct ftrace_ops *ops, int flag,
2240 struct inode *inode, struct file *file)
2241{
2242 struct ftrace_iterator *iter;
2243 struct ftrace_hash *hash;
2244 int ret = 0;
2245
2246 if (unlikely(ftrace_disabled))
2247 return -ENODEV;
2248
2249 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2250 if (!iter)
2251 return -ENOMEM;
2252
2253 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2254 kfree(iter);
2255 return -ENOMEM;
2256 }
2257
2258 if (flag & FTRACE_ITER_NOTRACE)
2259 hash = ops->notrace_hash;
2260 else
2261 hash = ops->filter_hash;
2262
2263 iter->ops = ops;
2264 iter->flags = flag;
2265
2266 if (file->f_mode & FMODE_WRITE) {
2267 mutex_lock(&ftrace_lock);
2268 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2269 mutex_unlock(&ftrace_lock);
2270
2271 if (!iter->hash) {
2272 trace_parser_put(&iter->parser);
2273 kfree(iter);
2274 return -ENOMEM;
2275 }
2276 }
2277
2278 mutex_lock(&ftrace_regex_lock);
2279
2280 if ((file->f_mode & FMODE_WRITE) &&
2281 (file->f_flags & O_TRUNC))
2282 ftrace_filter_reset(iter->hash);
2283
2284 if (file->f_mode & FMODE_READ) {
2285 iter->pg = ftrace_pages_start;
2286
2287 ret = seq_open(file, &show_ftrace_seq_ops);
2288 if (!ret) {
2289 struct seq_file *m = file->private_data;
2290 m->private = iter;
2291 } else {
2292 /* Failed */
2293 free_ftrace_hash(iter->hash);
2294 trace_parser_put(&iter->parser);
2295 kfree(iter);
2296 }
2297 } else
2298 file->private_data = iter;
2299 mutex_unlock(&ftrace_regex_lock);
2300
2301 return ret;
2302}
2303
2304static int
2305ftrace_filter_open(struct inode *inode, struct file *file)
2306{
2307 return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2308 inode, file);
2309}
2310
2311static int
2312ftrace_notrace_open(struct inode *inode, struct file *file)
2313{
2314 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2315 inode, file);
2316}
2317
2318static loff_t
2319ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2320{
2321 loff_t ret;
2322
2323 if (file->f_mode & FMODE_READ)
2324 ret = seq_lseek(file, offset, origin);
2325 else
2326 file->f_pos = ret = 1;
2327
2328 return ret;
2329}
2330
2331static int ftrace_match(char *str, char *regex, int len, int type)
2332{
2333 int matched = 0;
2334 int slen;
2335
2336 switch (type) {
2337 case MATCH_FULL:
2338 if (strcmp(str, regex) == 0)
2339 matched = 1;
2340 break;
2341 case MATCH_FRONT_ONLY:
2342 if (strncmp(str, regex, len) == 0)
2343 matched = 1;
2344 break;
2345 case MATCH_MIDDLE_ONLY:
2346 if (strstr(str, regex))
2347 matched = 1;
2348 break;
2349 case MATCH_END_ONLY:
2350 slen = strlen(str);
2351 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2352 matched = 1;
2353 break;
2354 }
2355
2356 return matched;
2357}
2358
2359static int
2360enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2361{
2362 struct ftrace_func_entry *entry;
2363 int ret = 0;
2364
2365 entry = ftrace_lookup_ip(hash, rec->ip);
2366 if (not) {
2367 /* Do nothing if it doesn't exist */
2368 if (!entry)
2369 return 0;
2370
2371 free_hash_entry(hash, entry);
2372 } else {
2373 /* Do nothing if it exists */
2374 if (entry)
2375 return 0;
2376
2377 ret = add_hash_entry(hash, rec->ip);
2378 }
2379 return ret;
2380}
2381
2382static int
2383ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2384 char *regex, int len, int type)
2385{
2386 char str[KSYM_SYMBOL_LEN];
2387 char *modname;
2388
2389 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2390
2391 if (mod) {
2392 /* module lookup requires matching the module */
2393 if (!modname || strcmp(modname, mod))
2394 return 0;
2395
2396 /* blank search means to match all funcs in the mod */
2397 if (!len)
2398 return 1;
2399 }
2400
2401 return ftrace_match(str, regex, len, type);
2402}
2403
2404static int
2405match_records(struct ftrace_hash *hash, char *buff,
2406 int len, char *mod, int not)
2407{
2408 unsigned search_len = 0;
2409 struct ftrace_page *pg;
2410 struct dyn_ftrace *rec;
2411 int type = MATCH_FULL;
2412 char *search = buff;
2413 int found = 0;
2414 int ret;
2415
2416 if (len) {
2417 type = filter_parse_regex(buff, len, &search, ¬);
2418 search_len = strlen(search);
2419 }
2420
2421 mutex_lock(&ftrace_lock);
2422
2423 if (unlikely(ftrace_disabled))
2424 goto out_unlock;
2425
2426 do_for_each_ftrace_rec(pg, rec) {
2427
2428 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2429 ret = enter_record(hash, rec, not);
2430 if (ret < 0) {
2431 found = ret;
2432 goto out_unlock;
2433 }
2434 found = 1;
2435 }
2436 } while_for_each_ftrace_rec();
2437 out_unlock:
2438 mutex_unlock(&ftrace_lock);
2439
2440 return found;
2441}
2442
2443static int
2444ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2445{
2446 return match_records(hash, buff, len, NULL, 0);
2447}
2448
2449static int
2450ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2451{
2452 int not = 0;
2453
2454 /* blank or '*' mean the same */
2455 if (strcmp(buff, "*") == 0)
2456 buff[0] = 0;
2457
2458 /* handle the case of 'dont filter this module' */
2459 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2460 buff[0] = 0;
2461 not = 1;
2462 }
2463
2464 return match_records(hash, buff, strlen(buff), mod, not);
2465}
2466
2467/*
2468 * We register the module command as a template to show others how
2469 * to register the a command as well.
2470 */
2471
2472static int
2473ftrace_mod_callback(struct ftrace_hash *hash,
2474 char *func, char *cmd, char *param, int enable)
2475{
2476 char *mod;
2477 int ret = -EINVAL;
2478
2479 /*
2480 * cmd == 'mod' because we only registered this func
2481 * for the 'mod' ftrace_func_command.
2482 * But if you register one func with multiple commands,
2483 * you can tell which command was used by the cmd
2484 * parameter.
2485 */
2486
2487 /* we must have a module name */
2488 if (!param)
2489 return ret;
2490
2491 mod = strsep(¶m, ":");
2492 if (!strlen(mod))
2493 return ret;
2494
2495 ret = ftrace_match_module_records(hash, func, mod);
2496 if (!ret)
2497 ret = -EINVAL;
2498 if (ret < 0)
2499 return ret;
2500
2501 return 0;
2502}
2503
2504static struct ftrace_func_command ftrace_mod_cmd = {
2505 .name = "mod",
2506 .func = ftrace_mod_callback,
2507};
2508
2509static int __init ftrace_mod_cmd_init(void)
2510{
2511 return register_ftrace_command(&ftrace_mod_cmd);
2512}
2513device_initcall(ftrace_mod_cmd_init);
2514
2515static void
2516function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2517{
2518 struct ftrace_func_probe *entry;
2519 struct hlist_head *hhd;
2520 struct hlist_node *n;
2521 unsigned long key;
2522
2523 key = hash_long(ip, FTRACE_HASH_BITS);
2524
2525 hhd = &ftrace_func_hash[key];
2526
2527 if (hlist_empty(hhd))
2528 return;
2529
2530 /*
2531 * Disable preemption for these calls to prevent a RCU grace
2532 * period. This syncs the hash iteration and freeing of items
2533 * on the hash. rcu_read_lock is too dangerous here.
2534 */
2535 preempt_disable_notrace();
2536 hlist_for_each_entry_rcu(entry, n, hhd, node) {
2537 if (entry->ip == ip)
2538 entry->ops->func(ip, parent_ip, &entry->data);
2539 }
2540 preempt_enable_notrace();
2541}
2542
2543static struct ftrace_ops trace_probe_ops __read_mostly =
2544{
2545 .func = function_trace_probe_call,
2546};
2547
2548static int ftrace_probe_registered;
2549
2550static void __enable_ftrace_function_probe(void)
2551{
2552 int ret;
2553 int i;
2554
2555 if (ftrace_probe_registered)
2556 return;
2557
2558 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2559 struct hlist_head *hhd = &ftrace_func_hash[i];
2560 if (hhd->first)
2561 break;
2562 }
2563 /* Nothing registered? */
2564 if (i == FTRACE_FUNC_HASHSIZE)
2565 return;
2566
2567 ret = __register_ftrace_function(&trace_probe_ops);
2568 if (!ret)
2569 ret = ftrace_startup(&trace_probe_ops, 0);
2570
2571 ftrace_probe_registered = 1;
2572}
2573
2574static void __disable_ftrace_function_probe(void)
2575{
2576 int ret;
2577 int i;
2578
2579 if (!ftrace_probe_registered)
2580 return;
2581
2582 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2583 struct hlist_head *hhd = &ftrace_func_hash[i];
2584 if (hhd->first)
2585 return;
2586 }
2587
2588 /* no more funcs left */
2589 ret = __unregister_ftrace_function(&trace_probe_ops);
2590 if (!ret)
2591 ftrace_shutdown(&trace_probe_ops, 0);
2592
2593 ftrace_probe_registered = 0;
2594}
2595
2596
2597static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2598{
2599 struct ftrace_func_probe *entry =
2600 container_of(rhp, struct ftrace_func_probe, rcu);
2601
2602 if (entry->ops->free)
2603 entry->ops->free(&entry->data);
2604 kfree(entry);
2605}
2606
2607
2608int
2609register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2610 void *data)
2611{
2612 struct ftrace_func_probe *entry;
2613 struct ftrace_page *pg;
2614 struct dyn_ftrace *rec;
2615 int type, len, not;
2616 unsigned long key;
2617 int count = 0;
2618 char *search;
2619
2620 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2621 len = strlen(search);
2622
2623 /* we do not support '!' for function probes */
2624 if (WARN_ON(not))
2625 return -EINVAL;
2626
2627 mutex_lock(&ftrace_lock);
2628
2629 if (unlikely(ftrace_disabled))
2630 goto out_unlock;
2631
2632 do_for_each_ftrace_rec(pg, rec) {
2633
2634 if (!ftrace_match_record(rec, NULL, search, len, type))
2635 continue;
2636
2637 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2638 if (!entry) {
2639 /* If we did not process any, then return error */
2640 if (!count)
2641 count = -ENOMEM;
2642 goto out_unlock;
2643 }
2644
2645 count++;
2646
2647 entry->data = data;
2648
2649 /*
2650 * The caller might want to do something special
2651 * for each function we find. We call the callback
2652 * to give the caller an opportunity to do so.
2653 */
2654 if (ops->callback) {
2655 if (ops->callback(rec->ip, &entry->data) < 0) {
2656 /* caller does not like this func */
2657 kfree(entry);
2658 continue;
2659 }
2660 }
2661
2662 entry->ops = ops;
2663 entry->ip = rec->ip;
2664
2665 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2666 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2667
2668 } while_for_each_ftrace_rec();
2669 __enable_ftrace_function_probe();
2670
2671 out_unlock:
2672 mutex_unlock(&ftrace_lock);
2673
2674 return count;
2675}
2676
2677enum {
2678 PROBE_TEST_FUNC = 1,
2679 PROBE_TEST_DATA = 2
2680};
2681
2682static void
2683__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2684 void *data, int flags)
2685{
2686 struct ftrace_func_probe *entry;
2687 struct hlist_node *n, *tmp;
2688 char str[KSYM_SYMBOL_LEN];
2689 int type = MATCH_FULL;
2690 int i, len = 0;
2691 char *search;
2692
2693 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2694 glob = NULL;
2695 else if (glob) {
2696 int not;
2697
2698 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2699 len = strlen(search);
2700
2701 /* we do not support '!' for function probes */
2702 if (WARN_ON(not))
2703 return;
2704 }
2705
2706 mutex_lock(&ftrace_lock);
2707 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2708 struct hlist_head *hhd = &ftrace_func_hash[i];
2709
2710 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2711
2712 /* break up if statements for readability */
2713 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2714 continue;
2715
2716 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2717 continue;
2718
2719 /* do this last, since it is the most expensive */
2720 if (glob) {
2721 kallsyms_lookup(entry->ip, NULL, NULL,
2722 NULL, str);
2723 if (!ftrace_match(str, glob, len, type))
2724 continue;
2725 }
2726
2727 hlist_del(&entry->node);
2728 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2729 }
2730 }
2731 __disable_ftrace_function_probe();
2732 mutex_unlock(&ftrace_lock);
2733}
2734
2735void
2736unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2737 void *data)
2738{
2739 __unregister_ftrace_function_probe(glob, ops, data,
2740 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2741}
2742
2743void
2744unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2745{
2746 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2747}
2748
2749void unregister_ftrace_function_probe_all(char *glob)
2750{
2751 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2752}
2753
2754static LIST_HEAD(ftrace_commands);
2755static DEFINE_MUTEX(ftrace_cmd_mutex);
2756
2757int register_ftrace_command(struct ftrace_func_command *cmd)
2758{
2759 struct ftrace_func_command *p;
2760 int ret = 0;
2761
2762 mutex_lock(&ftrace_cmd_mutex);
2763 list_for_each_entry(p, &ftrace_commands, list) {
2764 if (strcmp(cmd->name, p->name) == 0) {
2765 ret = -EBUSY;
2766 goto out_unlock;
2767 }
2768 }
2769 list_add(&cmd->list, &ftrace_commands);
2770 out_unlock:
2771 mutex_unlock(&ftrace_cmd_mutex);
2772
2773 return ret;
2774}
2775
2776int unregister_ftrace_command(struct ftrace_func_command *cmd)
2777{
2778 struct ftrace_func_command *p, *n;
2779 int ret = -ENODEV;
2780
2781 mutex_lock(&ftrace_cmd_mutex);
2782 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2783 if (strcmp(cmd->name, p->name) == 0) {
2784 ret = 0;
2785 list_del_init(&p->list);
2786 goto out_unlock;
2787 }
2788 }
2789 out_unlock:
2790 mutex_unlock(&ftrace_cmd_mutex);
2791
2792 return ret;
2793}
2794
2795static int ftrace_process_regex(struct ftrace_hash *hash,
2796 char *buff, int len, int enable)
2797{
2798 char *func, *command, *next = buff;
2799 struct ftrace_func_command *p;
2800 int ret = -EINVAL;
2801
2802 func = strsep(&next, ":");
2803
2804 if (!next) {
2805 ret = ftrace_match_records(hash, func, len);
2806 if (!ret)
2807 ret = -EINVAL;
2808 if (ret < 0)
2809 return ret;
2810 return 0;
2811 }
2812
2813 /* command found */
2814
2815 command = strsep(&next, ":");
2816
2817 mutex_lock(&ftrace_cmd_mutex);
2818 list_for_each_entry(p, &ftrace_commands, list) {
2819 if (strcmp(p->name, command) == 0) {
2820 ret = p->func(hash, func, command, next, enable);
2821 goto out_unlock;
2822 }
2823 }
2824 out_unlock:
2825 mutex_unlock(&ftrace_cmd_mutex);
2826
2827 return ret;
2828}
2829
2830static ssize_t
2831ftrace_regex_write(struct file *file, const char __user *ubuf,
2832 size_t cnt, loff_t *ppos, int enable)
2833{
2834 struct ftrace_iterator *iter;
2835 struct trace_parser *parser;
2836 ssize_t ret, read;
2837
2838 if (!cnt)
2839 return 0;
2840
2841 mutex_lock(&ftrace_regex_lock);
2842
2843 ret = -ENODEV;
2844 if (unlikely(ftrace_disabled))
2845 goto out_unlock;
2846
2847 if (file->f_mode & FMODE_READ) {
2848 struct seq_file *m = file->private_data;
2849 iter = m->private;
2850 } else
2851 iter = file->private_data;
2852
2853 parser = &iter->parser;
2854 read = trace_get_user(parser, ubuf, cnt, ppos);
2855
2856 if (read >= 0 && trace_parser_loaded(parser) &&
2857 !trace_parser_cont(parser)) {
2858 ret = ftrace_process_regex(iter->hash, parser->buffer,
2859 parser->idx, enable);
2860 trace_parser_clear(parser);
2861 if (ret)
2862 goto out_unlock;
2863 }
2864
2865 ret = read;
2866out_unlock:
2867 mutex_unlock(&ftrace_regex_lock);
2868
2869 return ret;
2870}
2871
2872static ssize_t
2873ftrace_filter_write(struct file *file, const char __user *ubuf,
2874 size_t cnt, loff_t *ppos)
2875{
2876 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2877}
2878
2879static ssize_t
2880ftrace_notrace_write(struct file *file, const char __user *ubuf,
2881 size_t cnt, loff_t *ppos)
2882{
2883 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2884}
2885
2886static int
2887ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
2888 int reset, int enable)
2889{
2890 struct ftrace_hash **orig_hash;
2891 struct ftrace_hash *hash;
2892 int ret;
2893
2894 /* All global ops uses the global ops filters */
2895 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
2896 ops = &global_ops;
2897
2898 if (unlikely(ftrace_disabled))
2899 return -ENODEV;
2900
2901 if (enable)
2902 orig_hash = &ops->filter_hash;
2903 else
2904 orig_hash = &ops->notrace_hash;
2905
2906 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
2907 if (!hash)
2908 return -ENOMEM;
2909
2910 mutex_lock(&ftrace_regex_lock);
2911 if (reset)
2912 ftrace_filter_reset(hash);
2913 if (buf)
2914 ftrace_match_records(hash, buf, len);
2915
2916 mutex_lock(&ftrace_lock);
2917 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
2918 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
2919 && ftrace_enabled)
2920 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2921
2922 mutex_unlock(&ftrace_lock);
2923
2924 mutex_unlock(&ftrace_regex_lock);
2925
2926 free_ftrace_hash(hash);
2927 return ret;
2928}
2929
2930/**
2931 * ftrace_set_filter - set a function to filter on in ftrace
2932 * @ops - the ops to set the filter with
2933 * @buf - the string that holds the function filter text.
2934 * @len - the length of the string.
2935 * @reset - non zero to reset all filters before applying this filter.
2936 *
2937 * Filters denote which functions should be enabled when tracing is enabled.
2938 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2939 */
2940void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
2941 int len, int reset)
2942{
2943 ftrace_set_regex(ops, buf, len, reset, 1);
2944}
2945EXPORT_SYMBOL_GPL(ftrace_set_filter);
2946
2947/**
2948 * ftrace_set_notrace - set a function to not trace in ftrace
2949 * @ops - the ops to set the notrace filter with
2950 * @buf - the string that holds the function notrace text.
2951 * @len - the length of the string.
2952 * @reset - non zero to reset all filters before applying this filter.
2953 *
2954 * Notrace Filters denote which functions should not be enabled when tracing
2955 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2956 * for tracing.
2957 */
2958void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
2959 int len, int reset)
2960{
2961 ftrace_set_regex(ops, buf, len, reset, 0);
2962}
2963EXPORT_SYMBOL_GPL(ftrace_set_notrace);
2964/**
2965 * ftrace_set_filter - set a function to filter on in ftrace
2966 * @ops - the ops to set the filter with
2967 * @buf - the string that holds the function filter text.
2968 * @len - the length of the string.
2969 * @reset - non zero to reset all filters before applying this filter.
2970 *
2971 * Filters denote which functions should be enabled when tracing is enabled.
2972 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2973 */
2974void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
2975{
2976 ftrace_set_regex(&global_ops, buf, len, reset, 1);
2977}
2978EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
2979
2980/**
2981 * ftrace_set_notrace - set a function to not trace in ftrace
2982 * @ops - the ops to set the notrace filter with
2983 * @buf - the string that holds the function notrace text.
2984 * @len - the length of the string.
2985 * @reset - non zero to reset all filters before applying this filter.
2986 *
2987 * Notrace Filters denote which functions should not be enabled when tracing
2988 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2989 * for tracing.
2990 */
2991void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
2992{
2993 ftrace_set_regex(&global_ops, buf, len, reset, 0);
2994}
2995EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
2996
2997/*
2998 * command line interface to allow users to set filters on boot up.
2999 */
3000#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3001static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3002static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3003
3004static int __init set_ftrace_notrace(char *str)
3005{
3006 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3007 return 1;
3008}
3009__setup("ftrace_notrace=", set_ftrace_notrace);
3010
3011static int __init set_ftrace_filter(char *str)
3012{
3013 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3014 return 1;
3015}
3016__setup("ftrace_filter=", set_ftrace_filter);
3017
3018#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3019static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3020static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3021
3022static int __init set_graph_function(char *str)
3023{
3024 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3025 return 1;
3026}
3027__setup("ftrace_graph_filter=", set_graph_function);
3028
3029static void __init set_ftrace_early_graph(char *buf)
3030{
3031 int ret;
3032 char *func;
3033
3034 while (buf) {
3035 func = strsep(&buf, ",");
3036 /* we allow only one expression at a time */
3037 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3038 func);
3039 if (ret)
3040 printk(KERN_DEBUG "ftrace: function %s not "
3041 "traceable\n", func);
3042 }
3043}
3044#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3045
3046static void __init
3047set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3048{
3049 char *func;
3050
3051 while (buf) {
3052 func = strsep(&buf, ",");
3053 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3054 }
3055}
3056
3057static void __init set_ftrace_early_filters(void)
3058{
3059 if (ftrace_filter_buf[0])
3060 set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3061 if (ftrace_notrace_buf[0])
3062 set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3063#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3064 if (ftrace_graph_buf[0])
3065 set_ftrace_early_graph(ftrace_graph_buf);
3066#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3067}
3068
3069static int
3070ftrace_regex_release(struct inode *inode, struct file *file)
3071{
3072 struct seq_file *m = (struct seq_file *)file->private_data;
3073 struct ftrace_iterator *iter;
3074 struct ftrace_hash **orig_hash;
3075 struct trace_parser *parser;
3076 int filter_hash;
3077 int ret;
3078
3079 mutex_lock(&ftrace_regex_lock);
3080 if (file->f_mode & FMODE_READ) {
3081 iter = m->private;
3082
3083 seq_release(inode, file);
3084 } else
3085 iter = file->private_data;
3086
3087 parser = &iter->parser;
3088 if (trace_parser_loaded(parser)) {
3089 parser->buffer[parser->idx] = 0;
3090 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3091 }
3092
3093 trace_parser_put(parser);
3094
3095 if (file->f_mode & FMODE_WRITE) {
3096 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3097
3098 if (filter_hash)
3099 orig_hash = &iter->ops->filter_hash;
3100 else
3101 orig_hash = &iter->ops->notrace_hash;
3102
3103 mutex_lock(&ftrace_lock);
3104 ret = ftrace_hash_move(iter->ops, filter_hash,
3105 orig_hash, iter->hash);
3106 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3107 && ftrace_enabled)
3108 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
3109
3110 mutex_unlock(&ftrace_lock);
3111 }
3112 free_ftrace_hash(iter->hash);
3113 kfree(iter);
3114
3115 mutex_unlock(&ftrace_regex_lock);
3116 return 0;
3117}
3118
3119static const struct file_operations ftrace_avail_fops = {
3120 .open = ftrace_avail_open,
3121 .read = seq_read,
3122 .llseek = seq_lseek,
3123 .release = seq_release_private,
3124};
3125
3126static const struct file_operations ftrace_enabled_fops = {
3127 .open = ftrace_enabled_open,
3128 .read = seq_read,
3129 .llseek = seq_lseek,
3130 .release = seq_release_private,
3131};
3132
3133static const struct file_operations ftrace_filter_fops = {
3134 .open = ftrace_filter_open,
3135 .read = seq_read,
3136 .write = ftrace_filter_write,
3137 .llseek = ftrace_regex_lseek,
3138 .release = ftrace_regex_release,
3139};
3140
3141static const struct file_operations ftrace_notrace_fops = {
3142 .open = ftrace_notrace_open,
3143 .read = seq_read,
3144 .write = ftrace_notrace_write,
3145 .llseek = ftrace_regex_lseek,
3146 .release = ftrace_regex_release,
3147};
3148
3149#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3150
3151static DEFINE_MUTEX(graph_lock);
3152
3153int ftrace_graph_count;
3154int ftrace_graph_filter_enabled;
3155unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3156
3157static void *
3158__g_next(struct seq_file *m, loff_t *pos)
3159{
3160 if (*pos >= ftrace_graph_count)
3161 return NULL;
3162 return &ftrace_graph_funcs[*pos];
3163}
3164
3165static void *
3166g_next(struct seq_file *m, void *v, loff_t *pos)
3167{
3168 (*pos)++;
3169 return __g_next(m, pos);
3170}
3171
3172static void *g_start(struct seq_file *m, loff_t *pos)
3173{
3174 mutex_lock(&graph_lock);
3175
3176 /* Nothing, tell g_show to print all functions are enabled */
3177 if (!ftrace_graph_filter_enabled && !*pos)
3178 return (void *)1;
3179
3180 return __g_next(m, pos);
3181}
3182
3183static void g_stop(struct seq_file *m, void *p)
3184{
3185 mutex_unlock(&graph_lock);
3186}
3187
3188static int g_show(struct seq_file *m, void *v)
3189{
3190 unsigned long *ptr = v;
3191
3192 if (!ptr)
3193 return 0;
3194
3195 if (ptr == (unsigned long *)1) {
3196 seq_printf(m, "#### all functions enabled ####\n");
3197 return 0;
3198 }
3199
3200 seq_printf(m, "%ps\n", (void *)*ptr);
3201
3202 return 0;
3203}
3204
3205static const struct seq_operations ftrace_graph_seq_ops = {
3206 .start = g_start,
3207 .next = g_next,
3208 .stop = g_stop,
3209 .show = g_show,
3210};
3211
3212static int
3213ftrace_graph_open(struct inode *inode, struct file *file)
3214{
3215 int ret = 0;
3216
3217 if (unlikely(ftrace_disabled))
3218 return -ENODEV;
3219
3220 mutex_lock(&graph_lock);
3221 if ((file->f_mode & FMODE_WRITE) &&
3222 (file->f_flags & O_TRUNC)) {
3223 ftrace_graph_filter_enabled = 0;
3224 ftrace_graph_count = 0;
3225 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3226 }
3227 mutex_unlock(&graph_lock);
3228
3229 if (file->f_mode & FMODE_READ)
3230 ret = seq_open(file, &ftrace_graph_seq_ops);
3231
3232 return ret;
3233}
3234
3235static int
3236ftrace_graph_release(struct inode *inode, struct file *file)
3237{
3238 if (file->f_mode & FMODE_READ)
3239 seq_release(inode, file);
3240 return 0;
3241}
3242
3243static int
3244ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3245{
3246 struct dyn_ftrace *rec;
3247 struct ftrace_page *pg;
3248 int search_len;
3249 int fail = 1;
3250 int type, not;
3251 char *search;
3252 bool exists;
3253 int i;
3254
3255 /* decode regex */
3256 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3257 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3258 return -EBUSY;
3259
3260 search_len = strlen(search);
3261
3262 mutex_lock(&ftrace_lock);
3263
3264 if (unlikely(ftrace_disabled)) {
3265 mutex_unlock(&ftrace_lock);
3266 return -ENODEV;
3267 }
3268
3269 do_for_each_ftrace_rec(pg, rec) {
3270
3271 if (rec->flags & FTRACE_FL_FREE)
3272 continue;
3273
3274 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3275 /* if it is in the array */
3276 exists = false;
3277 for (i = 0; i < *idx; i++) {
3278 if (array[i] == rec->ip) {
3279 exists = true;
3280 break;
3281 }
3282 }
3283
3284 if (!not) {
3285 fail = 0;
3286 if (!exists) {
3287 array[(*idx)++] = rec->ip;
3288 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3289 goto out;
3290 }
3291 } else {
3292 if (exists) {
3293 array[i] = array[--(*idx)];
3294 array[*idx] = 0;
3295 fail = 0;
3296 }
3297 }
3298 }
3299 } while_for_each_ftrace_rec();
3300out:
3301 mutex_unlock(&ftrace_lock);
3302
3303 if (fail)
3304 return -EINVAL;
3305
3306 ftrace_graph_filter_enabled = 1;
3307 return 0;
3308}
3309
3310static ssize_t
3311ftrace_graph_write(struct file *file, const char __user *ubuf,
3312 size_t cnt, loff_t *ppos)
3313{
3314 struct trace_parser parser;
3315 ssize_t read, ret;
3316
3317 if (!cnt)
3318 return 0;
3319
3320 mutex_lock(&graph_lock);
3321
3322 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3323 ret = -ENOMEM;
3324 goto out_unlock;
3325 }
3326
3327 read = trace_get_user(&parser, ubuf, cnt, ppos);
3328
3329 if (read >= 0 && trace_parser_loaded((&parser))) {
3330 parser.buffer[parser.idx] = 0;
3331
3332 /* we allow only one expression at a time */
3333 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3334 parser.buffer);
3335 if (ret)
3336 goto out_free;
3337 }
3338
3339 ret = read;
3340
3341out_free:
3342 trace_parser_put(&parser);
3343out_unlock:
3344 mutex_unlock(&graph_lock);
3345
3346 return ret;
3347}
3348
3349static const struct file_operations ftrace_graph_fops = {
3350 .open = ftrace_graph_open,
3351 .read = seq_read,
3352 .write = ftrace_graph_write,
3353 .release = ftrace_graph_release,
3354 .llseek = seq_lseek,
3355};
3356#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3357
3358static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3359{
3360
3361 trace_create_file("available_filter_functions", 0444,
3362 d_tracer, NULL, &ftrace_avail_fops);
3363
3364 trace_create_file("enabled_functions", 0444,
3365 d_tracer, NULL, &ftrace_enabled_fops);
3366
3367 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3368 NULL, &ftrace_filter_fops);
3369
3370 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3371 NULL, &ftrace_notrace_fops);
3372
3373#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3374 trace_create_file("set_graph_function", 0444, d_tracer,
3375 NULL,
3376 &ftrace_graph_fops);
3377#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3378
3379 return 0;
3380}
3381
3382static int ftrace_process_locs(struct module *mod,
3383 unsigned long *start,
3384 unsigned long *end)
3385{
3386 unsigned long *p;
3387 unsigned long addr;
3388 unsigned long flags = 0; /* Shut up gcc */
3389
3390 mutex_lock(&ftrace_lock);
3391 p = start;
3392 while (p < end) {
3393 addr = ftrace_call_adjust(*p++);
3394 /*
3395 * Some architecture linkers will pad between
3396 * the different mcount_loc sections of different
3397 * object files to satisfy alignments.
3398 * Skip any NULL pointers.
3399 */
3400 if (!addr)
3401 continue;
3402 ftrace_record_ip(addr);
3403 }
3404
3405 /*
3406 * We only need to disable interrupts on start up
3407 * because we are modifying code that an interrupt
3408 * may execute, and the modification is not atomic.
3409 * But for modules, nothing runs the code we modify
3410 * until we are finished with it, and there's no
3411 * reason to cause large interrupt latencies while we do it.
3412 */
3413 if (!mod)
3414 local_irq_save(flags);
3415 ftrace_update_code(mod);
3416 if (!mod)
3417 local_irq_restore(flags);
3418 mutex_unlock(&ftrace_lock);
3419
3420 return 0;
3421}
3422
3423#ifdef CONFIG_MODULES
3424void ftrace_release_mod(struct module *mod)
3425{
3426 struct dyn_ftrace *rec;
3427 struct ftrace_page *pg;
3428
3429 mutex_lock(&ftrace_lock);
3430
3431 if (ftrace_disabled)
3432 goto out_unlock;
3433
3434 do_for_each_ftrace_rec(pg, rec) {
3435 if (within_module_core(rec->ip, mod)) {
3436 /*
3437 * rec->ip is changed in ftrace_free_rec()
3438 * It should not between s and e if record was freed.
3439 */
3440 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
3441 ftrace_free_rec(rec);
3442 }
3443 } while_for_each_ftrace_rec();
3444 out_unlock:
3445 mutex_unlock(&ftrace_lock);
3446}
3447
3448static void ftrace_init_module(struct module *mod,
3449 unsigned long *start, unsigned long *end)
3450{
3451 if (ftrace_disabled || start == end)
3452 return;
3453 ftrace_process_locs(mod, start, end);
3454}
3455
3456static int ftrace_module_notify(struct notifier_block *self,
3457 unsigned long val, void *data)
3458{
3459 struct module *mod = data;
3460
3461 switch (val) {
3462 case MODULE_STATE_COMING:
3463 ftrace_init_module(mod, mod->ftrace_callsites,
3464 mod->ftrace_callsites +
3465 mod->num_ftrace_callsites);
3466 break;
3467 case MODULE_STATE_GOING:
3468 ftrace_release_mod(mod);
3469 break;
3470 }
3471
3472 return 0;
3473}
3474#else
3475static int ftrace_module_notify(struct notifier_block *self,
3476 unsigned long val, void *data)
3477{
3478 return 0;
3479}
3480#endif /* CONFIG_MODULES */
3481
3482struct notifier_block ftrace_module_nb = {
3483 .notifier_call = ftrace_module_notify,
3484 .priority = 0,
3485};
3486
3487extern unsigned long __start_mcount_loc[];
3488extern unsigned long __stop_mcount_loc[];
3489
3490void __init ftrace_init(void)
3491{
3492 unsigned long count, addr, flags;
3493 int ret;
3494
3495 /* Keep the ftrace pointer to the stub */
3496 addr = (unsigned long)ftrace_stub;
3497
3498 local_irq_save(flags);
3499 ftrace_dyn_arch_init(&addr);
3500 local_irq_restore(flags);
3501
3502 /* ftrace_dyn_arch_init places the return code in addr */
3503 if (addr)
3504 goto failed;
3505
3506 count = __stop_mcount_loc - __start_mcount_loc;
3507
3508 ret = ftrace_dyn_table_alloc(count);
3509 if (ret)
3510 goto failed;
3511
3512 last_ftrace_enabled = ftrace_enabled = 1;
3513
3514 ret = ftrace_process_locs(NULL,
3515 __start_mcount_loc,
3516 __stop_mcount_loc);
3517
3518 ret = register_module_notifier(&ftrace_module_nb);
3519 if (ret)
3520 pr_warning("Failed to register trace ftrace module notifier\n");
3521
3522 set_ftrace_early_filters();
3523
3524 return;
3525 failed:
3526 ftrace_disabled = 1;
3527}
3528
3529#else
3530
3531static struct ftrace_ops global_ops = {
3532 .func = ftrace_stub,
3533};
3534
3535static int __init ftrace_nodyn_init(void)
3536{
3537 ftrace_enabled = 1;
3538 return 0;
3539}
3540device_initcall(ftrace_nodyn_init);
3541
3542static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3543static inline void ftrace_startup_enable(int command) { }
3544/* Keep as macros so we do not need to define the commands */
3545# define ftrace_startup(ops, command) \
3546 ({ \
3547 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
3548 0; \
3549 })
3550# define ftrace_shutdown(ops, command) do { } while (0)
3551# define ftrace_startup_sysctl() do { } while (0)
3552# define ftrace_shutdown_sysctl() do { } while (0)
3553
3554static inline int
3555ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3556{
3557 return 1;
3558}
3559
3560#endif /* CONFIG_DYNAMIC_FTRACE */
3561
3562static void
3563ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3564{
3565 struct ftrace_ops *op;
3566
3567 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3568 return;
3569
3570 trace_recursion_set(TRACE_INTERNAL_BIT);
3571 /*
3572 * Some of the ops may be dynamically allocated,
3573 * they must be freed after a synchronize_sched().
3574 */
3575 preempt_disable_notrace();
3576 op = rcu_dereference_raw(ftrace_ops_list);
3577 while (op != &ftrace_list_end) {
3578 if (ftrace_ops_test(op, ip))
3579 op->func(ip, parent_ip);
3580 op = rcu_dereference_raw(op->next);
3581 };
3582 preempt_enable_notrace();
3583 trace_recursion_clear(TRACE_INTERNAL_BIT);
3584}
3585
3586static void clear_ftrace_swapper(void)
3587{
3588 struct task_struct *p;
3589 int cpu;
3590
3591 get_online_cpus();
3592 for_each_online_cpu(cpu) {
3593 p = idle_task(cpu);
3594 clear_tsk_trace_trace(p);
3595 }
3596 put_online_cpus();
3597}
3598
3599static void set_ftrace_swapper(void)
3600{
3601 struct task_struct *p;
3602 int cpu;
3603
3604 get_online_cpus();
3605 for_each_online_cpu(cpu) {
3606 p = idle_task(cpu);
3607 set_tsk_trace_trace(p);
3608 }
3609 put_online_cpus();
3610}
3611
3612static void clear_ftrace_pid(struct pid *pid)
3613{
3614 struct task_struct *p;
3615
3616 rcu_read_lock();
3617 do_each_pid_task(pid, PIDTYPE_PID, p) {
3618 clear_tsk_trace_trace(p);
3619 } while_each_pid_task(pid, PIDTYPE_PID, p);
3620 rcu_read_unlock();
3621
3622 put_pid(pid);
3623}
3624
3625static void set_ftrace_pid(struct pid *pid)
3626{
3627 struct task_struct *p;
3628
3629 rcu_read_lock();
3630 do_each_pid_task(pid, PIDTYPE_PID, p) {
3631 set_tsk_trace_trace(p);
3632 } while_each_pid_task(pid, PIDTYPE_PID, p);
3633 rcu_read_unlock();
3634}
3635
3636static void clear_ftrace_pid_task(struct pid *pid)
3637{
3638 if (pid == ftrace_swapper_pid)
3639 clear_ftrace_swapper();
3640 else
3641 clear_ftrace_pid(pid);
3642}
3643
3644static void set_ftrace_pid_task(struct pid *pid)
3645{
3646 if (pid == ftrace_swapper_pid)
3647 set_ftrace_swapper();
3648 else
3649 set_ftrace_pid(pid);
3650}
3651
3652static int ftrace_pid_add(int p)
3653{
3654 struct pid *pid;
3655 struct ftrace_pid *fpid;
3656 int ret = -EINVAL;
3657
3658 mutex_lock(&ftrace_lock);
3659
3660 if (!p)
3661 pid = ftrace_swapper_pid;
3662 else
3663 pid = find_get_pid(p);
3664
3665 if (!pid)
3666 goto out;
3667
3668 ret = 0;
3669
3670 list_for_each_entry(fpid, &ftrace_pids, list)
3671 if (fpid->pid == pid)
3672 goto out_put;
3673
3674 ret = -ENOMEM;
3675
3676 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3677 if (!fpid)
3678 goto out_put;
3679
3680 list_add(&fpid->list, &ftrace_pids);
3681 fpid->pid = pid;
3682
3683 set_ftrace_pid_task(pid);
3684
3685 ftrace_update_pid_func();
3686 ftrace_startup_enable(0);
3687
3688 mutex_unlock(&ftrace_lock);
3689 return 0;
3690
3691out_put:
3692 if (pid != ftrace_swapper_pid)
3693 put_pid(pid);
3694
3695out:
3696 mutex_unlock(&ftrace_lock);
3697 return ret;
3698}
3699
3700static void ftrace_pid_reset(void)
3701{
3702 struct ftrace_pid *fpid, *safe;
3703
3704 mutex_lock(&ftrace_lock);
3705 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3706 struct pid *pid = fpid->pid;
3707
3708 clear_ftrace_pid_task(pid);
3709
3710 list_del(&fpid->list);
3711 kfree(fpid);
3712 }
3713
3714 ftrace_update_pid_func();
3715 ftrace_startup_enable(0);
3716
3717 mutex_unlock(&ftrace_lock);
3718}
3719
3720static void *fpid_start(struct seq_file *m, loff_t *pos)
3721{
3722 mutex_lock(&ftrace_lock);
3723
3724 if (list_empty(&ftrace_pids) && (!*pos))
3725 return (void *) 1;
3726
3727 return seq_list_start(&ftrace_pids, *pos);
3728}
3729
3730static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3731{
3732 if (v == (void *)1)
3733 return NULL;
3734
3735 return seq_list_next(v, &ftrace_pids, pos);
3736}
3737
3738static void fpid_stop(struct seq_file *m, void *p)
3739{
3740 mutex_unlock(&ftrace_lock);
3741}
3742
3743static int fpid_show(struct seq_file *m, void *v)
3744{
3745 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3746
3747 if (v == (void *)1) {
3748 seq_printf(m, "no pid\n");
3749 return 0;
3750 }
3751
3752 if (fpid->pid == ftrace_swapper_pid)
3753 seq_printf(m, "swapper tasks\n");
3754 else
3755 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3756
3757 return 0;
3758}
3759
3760static const struct seq_operations ftrace_pid_sops = {
3761 .start = fpid_start,
3762 .next = fpid_next,
3763 .stop = fpid_stop,
3764 .show = fpid_show,
3765};
3766
3767static int
3768ftrace_pid_open(struct inode *inode, struct file *file)
3769{
3770 int ret = 0;
3771
3772 if ((file->f_mode & FMODE_WRITE) &&
3773 (file->f_flags & O_TRUNC))
3774 ftrace_pid_reset();
3775
3776 if (file->f_mode & FMODE_READ)
3777 ret = seq_open(file, &ftrace_pid_sops);
3778
3779 return ret;
3780}
3781
3782static ssize_t
3783ftrace_pid_write(struct file *filp, const char __user *ubuf,
3784 size_t cnt, loff_t *ppos)
3785{
3786 char buf[64], *tmp;
3787 long val;
3788 int ret;
3789
3790 if (cnt >= sizeof(buf))
3791 return -EINVAL;
3792
3793 if (copy_from_user(&buf, ubuf, cnt))
3794 return -EFAULT;
3795
3796 buf[cnt] = 0;
3797
3798 /*
3799 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3800 * to clean the filter quietly.
3801 */
3802 tmp = strstrip(buf);
3803 if (strlen(tmp) == 0)
3804 return 1;
3805
3806 ret = strict_strtol(tmp, 10, &val);
3807 if (ret < 0)
3808 return ret;
3809
3810 ret = ftrace_pid_add(val);
3811
3812 return ret ? ret : cnt;
3813}
3814
3815static int
3816ftrace_pid_release(struct inode *inode, struct file *file)
3817{
3818 if (file->f_mode & FMODE_READ)
3819 seq_release(inode, file);
3820
3821 return 0;
3822}
3823
3824static const struct file_operations ftrace_pid_fops = {
3825 .open = ftrace_pid_open,
3826 .write = ftrace_pid_write,
3827 .read = seq_read,
3828 .llseek = seq_lseek,
3829 .release = ftrace_pid_release,
3830};
3831
3832static __init int ftrace_init_debugfs(void)
3833{
3834 struct dentry *d_tracer;
3835
3836 d_tracer = tracing_init_dentry();
3837 if (!d_tracer)
3838 return 0;
3839
3840 ftrace_init_dyn_debugfs(d_tracer);
3841
3842 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3843 NULL, &ftrace_pid_fops);
3844
3845 ftrace_profile_debugfs(d_tracer);
3846
3847 return 0;
3848}
3849fs_initcall(ftrace_init_debugfs);
3850
3851/**
3852 * ftrace_kill - kill ftrace
3853 *
3854 * This function should be used by panic code. It stops ftrace
3855 * but in a not so nice way. If you need to simply kill ftrace
3856 * from a non-atomic section, use ftrace_kill.
3857 */
3858void ftrace_kill(void)
3859{
3860 ftrace_disabled = 1;
3861 ftrace_enabled = 0;
3862 clear_ftrace_function();
3863}
3864
3865/**
3866 * register_ftrace_function - register a function for profiling
3867 * @ops - ops structure that holds the function for profiling.
3868 *
3869 * Register a function to be called by all functions in the
3870 * kernel.
3871 *
3872 * Note: @ops->func and all the functions it calls must be labeled
3873 * with "notrace", otherwise it will go into a
3874 * recursive loop.
3875 */
3876int register_ftrace_function(struct ftrace_ops *ops)
3877{
3878 int ret = -1;
3879
3880 mutex_lock(&ftrace_lock);
3881
3882 if (unlikely(ftrace_disabled))
3883 goto out_unlock;
3884
3885 ret = __register_ftrace_function(ops);
3886 if (!ret)
3887 ret = ftrace_startup(ops, 0);
3888
3889
3890 out_unlock:
3891 mutex_unlock(&ftrace_lock);
3892 return ret;
3893}
3894EXPORT_SYMBOL_GPL(register_ftrace_function);
3895
3896/**
3897 * unregister_ftrace_function - unregister a function for profiling.
3898 * @ops - ops structure that holds the function to unregister
3899 *
3900 * Unregister a function that was added to be called by ftrace profiling.
3901 */
3902int unregister_ftrace_function(struct ftrace_ops *ops)
3903{
3904 int ret;
3905
3906 mutex_lock(&ftrace_lock);
3907 ret = __unregister_ftrace_function(ops);
3908 if (!ret)
3909 ftrace_shutdown(ops, 0);
3910 mutex_unlock(&ftrace_lock);
3911
3912 return ret;
3913}
3914EXPORT_SYMBOL_GPL(unregister_ftrace_function);
3915
3916int
3917ftrace_enable_sysctl(struct ctl_table *table, int write,
3918 void __user *buffer, size_t *lenp,
3919 loff_t *ppos)
3920{
3921 int ret = -ENODEV;
3922
3923 mutex_lock(&ftrace_lock);
3924
3925 if (unlikely(ftrace_disabled))
3926 goto out;
3927
3928 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3929
3930 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3931 goto out;
3932
3933 last_ftrace_enabled = !!ftrace_enabled;
3934
3935 if (ftrace_enabled) {
3936
3937 ftrace_startup_sysctl();
3938
3939 /* we are starting ftrace again */
3940 if (ftrace_ops_list != &ftrace_list_end) {
3941 if (ftrace_ops_list->next == &ftrace_list_end)
3942 ftrace_trace_function = ftrace_ops_list->func;
3943 else
3944 ftrace_trace_function = ftrace_ops_list_func;
3945 }
3946
3947 } else {
3948 /* stopping ftrace calls (just send to ftrace_stub) */
3949 ftrace_trace_function = ftrace_stub;
3950
3951 ftrace_shutdown_sysctl();
3952 }
3953
3954 out:
3955 mutex_unlock(&ftrace_lock);
3956 return ret;
3957}
3958
3959#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3960
3961static int ftrace_graph_active;
3962static struct notifier_block ftrace_suspend_notifier;
3963
3964int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3965{
3966 return 0;
3967}
3968
3969/* The callbacks that hook a function */
3970trace_func_graph_ret_t ftrace_graph_return =
3971 (trace_func_graph_ret_t)ftrace_stub;
3972trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3973
3974/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3975static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3976{
3977 int i;
3978 int ret = 0;
3979 unsigned long flags;
3980 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3981 struct task_struct *g, *t;
3982
3983 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3984 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3985 * sizeof(struct ftrace_ret_stack),
3986 GFP_KERNEL);
3987 if (!ret_stack_list[i]) {
3988 start = 0;
3989 end = i;
3990 ret = -ENOMEM;
3991 goto free;
3992 }
3993 }
3994
3995 read_lock_irqsave(&tasklist_lock, flags);
3996 do_each_thread(g, t) {
3997 if (start == end) {
3998 ret = -EAGAIN;
3999 goto unlock;
4000 }
4001
4002 if (t->ret_stack == NULL) {
4003 atomic_set(&t->tracing_graph_pause, 0);
4004 atomic_set(&t->trace_overrun, 0);
4005 t->curr_ret_stack = -1;
4006 /* Make sure the tasks see the -1 first: */
4007 smp_wmb();
4008 t->ret_stack = ret_stack_list[start++];
4009 }
4010 } while_each_thread(g, t);
4011
4012unlock:
4013 read_unlock_irqrestore(&tasklist_lock, flags);
4014free:
4015 for (i = start; i < end; i++)
4016 kfree(ret_stack_list[i]);
4017 return ret;
4018}
4019
4020static void
4021ftrace_graph_probe_sched_switch(void *ignore,
4022 struct task_struct *prev, struct task_struct *next)
4023{
4024 unsigned long long timestamp;
4025 int index;
4026
4027 /*
4028 * Does the user want to count the time a function was asleep.
4029 * If so, do not update the time stamps.
4030 */
4031 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4032 return;
4033
4034 timestamp = trace_clock_local();
4035
4036 prev->ftrace_timestamp = timestamp;
4037
4038 /* only process tasks that we timestamped */
4039 if (!next->ftrace_timestamp)
4040 return;
4041
4042 /*
4043 * Update all the counters in next to make up for the
4044 * time next was sleeping.
4045 */
4046 timestamp -= next->ftrace_timestamp;
4047
4048 for (index = next->curr_ret_stack; index >= 0; index--)
4049 next->ret_stack[index].calltime += timestamp;
4050}
4051
4052/* Allocate a return stack for each task */
4053static int start_graph_tracing(void)
4054{
4055 struct ftrace_ret_stack **ret_stack_list;
4056 int ret, cpu;
4057
4058 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4059 sizeof(struct ftrace_ret_stack *),
4060 GFP_KERNEL);
4061
4062 if (!ret_stack_list)
4063 return -ENOMEM;
4064
4065 /* The cpu_boot init_task->ret_stack will never be freed */
4066 for_each_online_cpu(cpu) {
4067 if (!idle_task(cpu)->ret_stack)
4068 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4069 }
4070
4071 do {
4072 ret = alloc_retstack_tasklist(ret_stack_list);
4073 } while (ret == -EAGAIN);
4074
4075 if (!ret) {
4076 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4077 if (ret)
4078 pr_info("ftrace_graph: Couldn't activate tracepoint"
4079 " probe to kernel_sched_switch\n");
4080 }
4081
4082 kfree(ret_stack_list);
4083 return ret;
4084}
4085
4086/*
4087 * Hibernation protection.
4088 * The state of the current task is too much unstable during
4089 * suspend/restore to disk. We want to protect against that.
4090 */
4091static int
4092ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4093 void *unused)
4094{
4095 switch (state) {
4096 case PM_HIBERNATION_PREPARE:
4097 pause_graph_tracing();
4098 break;
4099
4100 case PM_POST_HIBERNATION:
4101 unpause_graph_tracing();
4102 break;
4103 }
4104 return NOTIFY_DONE;
4105}
4106
4107int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4108 trace_func_graph_ent_t entryfunc)
4109{
4110 int ret = 0;
4111
4112 mutex_lock(&ftrace_lock);
4113
4114 /* we currently allow only one tracer registered at a time */
4115 if (ftrace_graph_active) {
4116 ret = -EBUSY;
4117 goto out;
4118 }
4119
4120 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4121 register_pm_notifier(&ftrace_suspend_notifier);
4122
4123 ftrace_graph_active++;
4124 ret = start_graph_tracing();
4125 if (ret) {
4126 ftrace_graph_active--;
4127 goto out;
4128 }
4129
4130 ftrace_graph_return = retfunc;
4131 ftrace_graph_entry = entryfunc;
4132
4133 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4134
4135out:
4136 mutex_unlock(&ftrace_lock);
4137 return ret;
4138}
4139
4140void unregister_ftrace_graph(void)
4141{
4142 mutex_lock(&ftrace_lock);
4143
4144 if (unlikely(!ftrace_graph_active))
4145 goto out;
4146
4147 ftrace_graph_active--;
4148 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4149 ftrace_graph_entry = ftrace_graph_entry_stub;
4150 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4151 unregister_pm_notifier(&ftrace_suspend_notifier);
4152 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4153
4154 out:
4155 mutex_unlock(&ftrace_lock);
4156}
4157
4158static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4159
4160static void
4161graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4162{
4163 atomic_set(&t->tracing_graph_pause, 0);
4164 atomic_set(&t->trace_overrun, 0);
4165 t->ftrace_timestamp = 0;
4166 /* make curr_ret_stack visible before we add the ret_stack */
4167 smp_wmb();
4168 t->ret_stack = ret_stack;
4169}
4170
4171/*
4172 * Allocate a return stack for the idle task. May be the first
4173 * time through, or it may be done by CPU hotplug online.
4174 */
4175void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4176{
4177 t->curr_ret_stack = -1;
4178 /*
4179 * The idle task has no parent, it either has its own
4180 * stack or no stack at all.
4181 */
4182 if (t->ret_stack)
4183 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4184
4185 if (ftrace_graph_active) {
4186 struct ftrace_ret_stack *ret_stack;
4187
4188 ret_stack = per_cpu(idle_ret_stack, cpu);
4189 if (!ret_stack) {
4190 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4191 * sizeof(struct ftrace_ret_stack),
4192 GFP_KERNEL);
4193 if (!ret_stack)
4194 return;
4195 per_cpu(idle_ret_stack, cpu) = ret_stack;
4196 }
4197 graph_init_task(t, ret_stack);
4198 }
4199}
4200
4201/* Allocate a return stack for newly created task */
4202void ftrace_graph_init_task(struct task_struct *t)
4203{
4204 /* Make sure we do not use the parent ret_stack */
4205 t->ret_stack = NULL;
4206 t->curr_ret_stack = -1;
4207
4208 if (ftrace_graph_active) {
4209 struct ftrace_ret_stack *ret_stack;
4210
4211 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4212 * sizeof(struct ftrace_ret_stack),
4213 GFP_KERNEL);
4214 if (!ret_stack)
4215 return;
4216 graph_init_task(t, ret_stack);
4217 }
4218}
4219
4220void ftrace_graph_exit_task(struct task_struct *t)
4221{
4222 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4223
4224 t->ret_stack = NULL;
4225 /* NULL must become visible to IRQs before we free it: */
4226 barrier();
4227
4228 kfree(ret_stack);
4229}
4230
4231void ftrace_graph_stop(void)
4232{
4233 ftrace_stop();
4234}
4235#endif