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1/*
2 * Infrastructure for profiling code inserted by 'gcc -pg'.
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code in the latency_tracer, that is:
11 *
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15
16#include <linux/stop_machine.h>
17#include <linux/clocksource.h>
18#include <linux/sched/task.h>
19#include <linux/kallsyms.h>
20#include <linux/seq_file.h>
21#include <linux/suspend.h>
22#include <linux/tracefs.h>
23#include <linux/hardirq.h>
24#include <linux/kthread.h>
25#include <linux/uaccess.h>
26#include <linux/bsearch.h>
27#include <linux/module.h>
28#include <linux/ftrace.h>
29#include <linux/sysctl.h>
30#include <linux/slab.h>
31#include <linux/ctype.h>
32#include <linux/sort.h>
33#include <linux/list.h>
34#include <linux/hash.h>
35#include <linux/rcupdate.h>
36
37#include <trace/events/sched.h>
38
39#include <asm/sections.h>
40#include <asm/setup.h>
41
42#include "trace_output.h"
43#include "trace_stat.h"
44
45#define FTRACE_WARN_ON(cond) \
46 ({ \
47 int ___r = cond; \
48 if (WARN_ON(___r)) \
49 ftrace_kill(); \
50 ___r; \
51 })
52
53#define FTRACE_WARN_ON_ONCE(cond) \
54 ({ \
55 int ___r = cond; \
56 if (WARN_ON_ONCE(___r)) \
57 ftrace_kill(); \
58 ___r; \
59 })
60
61/* hash bits for specific function selection */
62#define FTRACE_HASH_BITS 7
63#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
64#define FTRACE_HASH_DEFAULT_BITS 10
65#define FTRACE_HASH_MAX_BITS 12
66
67#ifdef CONFIG_DYNAMIC_FTRACE
68#define INIT_OPS_HASH(opsname) \
69 .func_hash = &opsname.local_hash, \
70 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
71#define ASSIGN_OPS_HASH(opsname, val) \
72 .func_hash = val, \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
74#else
75#define INIT_OPS_HASH(opsname)
76#define ASSIGN_OPS_HASH(opsname, val)
77#endif
78
79static struct ftrace_ops ftrace_list_end __read_mostly = {
80 .func = ftrace_stub,
81 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
82 INIT_OPS_HASH(ftrace_list_end)
83};
84
85/* ftrace_enabled is a method to turn ftrace on or off */
86int ftrace_enabled __read_mostly;
87static int last_ftrace_enabled;
88
89/* Current function tracing op */
90struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
91/* What to set function_trace_op to */
92static struct ftrace_ops *set_function_trace_op;
93
94static bool ftrace_pids_enabled(struct ftrace_ops *ops)
95{
96 struct trace_array *tr;
97
98 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
99 return false;
100
101 tr = ops->private;
102
103 return tr->function_pids != NULL;
104}
105
106static void ftrace_update_trampoline(struct ftrace_ops *ops);
107
108/*
109 * ftrace_disabled is set when an anomaly is discovered.
110 * ftrace_disabled is much stronger than ftrace_enabled.
111 */
112static int ftrace_disabled __read_mostly;
113
114static DEFINE_MUTEX(ftrace_lock);
115
116static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
117ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
118static struct ftrace_ops global_ops;
119
120#if ARCH_SUPPORTS_FTRACE_OPS
121static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
122 struct ftrace_ops *op, struct pt_regs *regs);
123#else
124/* See comment below, where ftrace_ops_list_func is defined */
125static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
126#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
127#endif
128
129/*
130 * Traverse the ftrace_global_list, invoking all entries. The reason that we
131 * can use rcu_dereference_raw_notrace() is that elements removed from this list
132 * are simply leaked, so there is no need to interact with a grace-period
133 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
134 * concurrent insertions into the ftrace_global_list.
135 *
136 * Silly Alpha and silly pointer-speculation compiler optimizations!
137 */
138#define do_for_each_ftrace_op(op, list) \
139 op = rcu_dereference_raw_notrace(list); \
140 do
141
142/*
143 * Optimized for just a single item in the list (as that is the normal case).
144 */
145#define while_for_each_ftrace_op(op) \
146 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
147 unlikely((op) != &ftrace_list_end))
148
149static inline void ftrace_ops_init(struct ftrace_ops *ops)
150{
151#ifdef CONFIG_DYNAMIC_FTRACE
152 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
153 mutex_init(&ops->local_hash.regex_lock);
154 ops->func_hash = &ops->local_hash;
155 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
156 }
157#endif
158}
159
160/**
161 * ftrace_nr_registered_ops - return number of ops registered
162 *
163 * Returns the number of ftrace_ops registered and tracing functions
164 */
165int ftrace_nr_registered_ops(void)
166{
167 struct ftrace_ops *ops;
168 int cnt = 0;
169
170 mutex_lock(&ftrace_lock);
171
172 for (ops = rcu_dereference_protected(ftrace_ops_list,
173 lockdep_is_held(&ftrace_lock));
174 ops != &ftrace_list_end;
175 ops = rcu_dereference_protected(ops->next,
176 lockdep_is_held(&ftrace_lock)))
177 cnt++;
178
179 mutex_unlock(&ftrace_lock);
180
181 return cnt;
182}
183
184static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
185 struct ftrace_ops *op, struct pt_regs *regs)
186{
187 struct trace_array *tr = op->private;
188
189 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
190 return;
191
192 op->saved_func(ip, parent_ip, op, regs);
193}
194
195/**
196 * clear_ftrace_function - reset the ftrace function
197 *
198 * This NULLs the ftrace function and in essence stops
199 * tracing. There may be lag
200 */
201void clear_ftrace_function(void)
202{
203 ftrace_trace_function = ftrace_stub;
204}
205
206static void ftrace_sync(struct work_struct *work)
207{
208 /*
209 * This function is just a stub to implement a hard force
210 * of synchronize_sched(). This requires synchronizing
211 * tasks even in userspace and idle.
212 *
213 * Yes, function tracing is rude.
214 */
215}
216
217static void ftrace_sync_ipi(void *data)
218{
219 /* Probably not needed, but do it anyway */
220 smp_rmb();
221}
222
223#ifdef CONFIG_FUNCTION_GRAPH_TRACER
224static void update_function_graph_func(void);
225
226/* Both enabled by default (can be cleared by function_graph tracer flags */
227static bool fgraph_sleep_time = true;
228static bool fgraph_graph_time = true;
229
230#else
231static inline void update_function_graph_func(void) { }
232#endif
233
234
235static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
236{
237 /*
238 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
239 * then it needs to call the list anyway.
240 */
241 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
242 FTRACE_FORCE_LIST_FUNC)
243 return ftrace_ops_list_func;
244
245 return ftrace_ops_get_func(ops);
246}
247
248static void update_ftrace_function(void)
249{
250 ftrace_func_t func;
251
252 /*
253 * Prepare the ftrace_ops that the arch callback will use.
254 * If there's only one ftrace_ops registered, the ftrace_ops_list
255 * will point to the ops we want.
256 */
257 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
258 lockdep_is_held(&ftrace_lock));
259
260 /* If there's no ftrace_ops registered, just call the stub function */
261 if (set_function_trace_op == &ftrace_list_end) {
262 func = ftrace_stub;
263
264 /*
265 * If we are at the end of the list and this ops is
266 * recursion safe and not dynamic and the arch supports passing ops,
267 * then have the mcount trampoline call the function directly.
268 */
269 } else if (rcu_dereference_protected(ftrace_ops_list->next,
270 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
271 func = ftrace_ops_get_list_func(ftrace_ops_list);
272
273 } else {
274 /* Just use the default ftrace_ops */
275 set_function_trace_op = &ftrace_list_end;
276 func = ftrace_ops_list_func;
277 }
278
279 update_function_graph_func();
280
281 /* If there's no change, then do nothing more here */
282 if (ftrace_trace_function == func)
283 return;
284
285 /*
286 * If we are using the list function, it doesn't care
287 * about the function_trace_ops.
288 */
289 if (func == ftrace_ops_list_func) {
290 ftrace_trace_function = func;
291 /*
292 * Don't even bother setting function_trace_ops,
293 * it would be racy to do so anyway.
294 */
295 return;
296 }
297
298#ifndef CONFIG_DYNAMIC_FTRACE
299 /*
300 * For static tracing, we need to be a bit more careful.
301 * The function change takes affect immediately. Thus,
302 * we need to coorditate the setting of the function_trace_ops
303 * with the setting of the ftrace_trace_function.
304 *
305 * Set the function to the list ops, which will call the
306 * function we want, albeit indirectly, but it handles the
307 * ftrace_ops and doesn't depend on function_trace_op.
308 */
309 ftrace_trace_function = ftrace_ops_list_func;
310 /*
311 * Make sure all CPUs see this. Yes this is slow, but static
312 * tracing is slow and nasty to have enabled.
313 */
314 schedule_on_each_cpu(ftrace_sync);
315 /* Now all cpus are using the list ops. */
316 function_trace_op = set_function_trace_op;
317 /* Make sure the function_trace_op is visible on all CPUs */
318 smp_wmb();
319 /* Nasty way to force a rmb on all cpus */
320 smp_call_function(ftrace_sync_ipi, NULL, 1);
321 /* OK, we are all set to update the ftrace_trace_function now! */
322#endif /* !CONFIG_DYNAMIC_FTRACE */
323
324 ftrace_trace_function = func;
325}
326
327int using_ftrace_ops_list_func(void)
328{
329 return ftrace_trace_function == ftrace_ops_list_func;
330}
331
332static void add_ftrace_ops(struct ftrace_ops __rcu **list,
333 struct ftrace_ops *ops)
334{
335 rcu_assign_pointer(ops->next, *list);
336
337 /*
338 * We are entering ops into the list but another
339 * CPU might be walking that list. We need to make sure
340 * the ops->next pointer is valid before another CPU sees
341 * the ops pointer included into the list.
342 */
343 rcu_assign_pointer(*list, ops);
344}
345
346static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
347 struct ftrace_ops *ops)
348{
349 struct ftrace_ops **p;
350
351 /*
352 * If we are removing the last function, then simply point
353 * to the ftrace_stub.
354 */
355 if (rcu_dereference_protected(*list,
356 lockdep_is_held(&ftrace_lock)) == ops &&
357 rcu_dereference_protected(ops->next,
358 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
359 *list = &ftrace_list_end;
360 return 0;
361 }
362
363 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
364 if (*p == ops)
365 break;
366
367 if (*p != ops)
368 return -1;
369
370 *p = (*p)->next;
371 return 0;
372}
373
374static void ftrace_update_trampoline(struct ftrace_ops *ops);
375
376static int __register_ftrace_function(struct ftrace_ops *ops)
377{
378 if (ops->flags & FTRACE_OPS_FL_DELETED)
379 return -EINVAL;
380
381 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
382 return -EBUSY;
383
384#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
385 /*
386 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
387 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
388 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
389 */
390 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
391 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
392 return -EINVAL;
393
394 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
395 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
396#endif
397
398 if (!core_kernel_data((unsigned long)ops))
399 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
400
401 add_ftrace_ops(&ftrace_ops_list, ops);
402
403 /* Always save the function, and reset at unregistering */
404 ops->saved_func = ops->func;
405
406 if (ftrace_pids_enabled(ops))
407 ops->func = ftrace_pid_func;
408
409 ftrace_update_trampoline(ops);
410
411 if (ftrace_enabled)
412 update_ftrace_function();
413
414 return 0;
415}
416
417static int __unregister_ftrace_function(struct ftrace_ops *ops)
418{
419 int ret;
420
421 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
422 return -EBUSY;
423
424 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
425
426 if (ret < 0)
427 return ret;
428
429 if (ftrace_enabled)
430 update_ftrace_function();
431
432 ops->func = ops->saved_func;
433
434 return 0;
435}
436
437static void ftrace_update_pid_func(void)
438{
439 struct ftrace_ops *op;
440
441 /* Only do something if we are tracing something */
442 if (ftrace_trace_function == ftrace_stub)
443 return;
444
445 do_for_each_ftrace_op(op, ftrace_ops_list) {
446 if (op->flags & FTRACE_OPS_FL_PID) {
447 op->func = ftrace_pids_enabled(op) ?
448 ftrace_pid_func : op->saved_func;
449 ftrace_update_trampoline(op);
450 }
451 } while_for_each_ftrace_op(op);
452
453 update_ftrace_function();
454}
455
456#ifdef CONFIG_FUNCTION_PROFILER
457struct ftrace_profile {
458 struct hlist_node node;
459 unsigned long ip;
460 unsigned long counter;
461#ifdef CONFIG_FUNCTION_GRAPH_TRACER
462 unsigned long long time;
463 unsigned long long time_squared;
464#endif
465};
466
467struct ftrace_profile_page {
468 struct ftrace_profile_page *next;
469 unsigned long index;
470 struct ftrace_profile records[];
471};
472
473struct ftrace_profile_stat {
474 atomic_t disabled;
475 struct hlist_head *hash;
476 struct ftrace_profile_page *pages;
477 struct ftrace_profile_page *start;
478 struct tracer_stat stat;
479};
480
481#define PROFILE_RECORDS_SIZE \
482 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
483
484#define PROFILES_PER_PAGE \
485 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
486
487static int ftrace_profile_enabled __read_mostly;
488
489/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
490static DEFINE_MUTEX(ftrace_profile_lock);
491
492static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
493
494#define FTRACE_PROFILE_HASH_BITS 10
495#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
496
497static void *
498function_stat_next(void *v, int idx)
499{
500 struct ftrace_profile *rec = v;
501 struct ftrace_profile_page *pg;
502
503 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
504
505 again:
506 if (idx != 0)
507 rec++;
508
509 if ((void *)rec >= (void *)&pg->records[pg->index]) {
510 pg = pg->next;
511 if (!pg)
512 return NULL;
513 rec = &pg->records[0];
514 if (!rec->counter)
515 goto again;
516 }
517
518 return rec;
519}
520
521static void *function_stat_start(struct tracer_stat *trace)
522{
523 struct ftrace_profile_stat *stat =
524 container_of(trace, struct ftrace_profile_stat, stat);
525
526 if (!stat || !stat->start)
527 return NULL;
528
529 return function_stat_next(&stat->start->records[0], 0);
530}
531
532#ifdef CONFIG_FUNCTION_GRAPH_TRACER
533/* function graph compares on total time */
534static int function_stat_cmp(void *p1, void *p2)
535{
536 struct ftrace_profile *a = p1;
537 struct ftrace_profile *b = p2;
538
539 if (a->time < b->time)
540 return -1;
541 if (a->time > b->time)
542 return 1;
543 else
544 return 0;
545}
546#else
547/* not function graph compares against hits */
548static int function_stat_cmp(void *p1, void *p2)
549{
550 struct ftrace_profile *a = p1;
551 struct ftrace_profile *b = p2;
552
553 if (a->counter < b->counter)
554 return -1;
555 if (a->counter > b->counter)
556 return 1;
557 else
558 return 0;
559}
560#endif
561
562static int function_stat_headers(struct seq_file *m)
563{
564#ifdef CONFIG_FUNCTION_GRAPH_TRACER
565 seq_puts(m, " Function "
566 "Hit Time Avg s^2\n"
567 " -------- "
568 "--- ---- --- ---\n");
569#else
570 seq_puts(m, " Function Hit\n"
571 " -------- ---\n");
572#endif
573 return 0;
574}
575
576static int function_stat_show(struct seq_file *m, void *v)
577{
578 struct ftrace_profile *rec = v;
579 char str[KSYM_SYMBOL_LEN];
580 int ret = 0;
581#ifdef CONFIG_FUNCTION_GRAPH_TRACER
582 static struct trace_seq s;
583 unsigned long long avg;
584 unsigned long long stddev;
585#endif
586 mutex_lock(&ftrace_profile_lock);
587
588 /* we raced with function_profile_reset() */
589 if (unlikely(rec->counter == 0)) {
590 ret = -EBUSY;
591 goto out;
592 }
593
594#ifdef CONFIG_FUNCTION_GRAPH_TRACER
595 avg = rec->time;
596 do_div(avg, rec->counter);
597 if (tracing_thresh && (avg < tracing_thresh))
598 goto out;
599#endif
600
601 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
602 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
603
604#ifdef CONFIG_FUNCTION_GRAPH_TRACER
605 seq_puts(m, " ");
606
607 /* Sample standard deviation (s^2) */
608 if (rec->counter <= 1)
609 stddev = 0;
610 else {
611 /*
612 * Apply Welford's method:
613 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
614 */
615 stddev = rec->counter * rec->time_squared -
616 rec->time * rec->time;
617
618 /*
619 * Divide only 1000 for ns^2 -> us^2 conversion.
620 * trace_print_graph_duration will divide 1000 again.
621 */
622 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
623 }
624
625 trace_seq_init(&s);
626 trace_print_graph_duration(rec->time, &s);
627 trace_seq_puts(&s, " ");
628 trace_print_graph_duration(avg, &s);
629 trace_seq_puts(&s, " ");
630 trace_print_graph_duration(stddev, &s);
631 trace_print_seq(m, &s);
632#endif
633 seq_putc(m, '\n');
634out:
635 mutex_unlock(&ftrace_profile_lock);
636
637 return ret;
638}
639
640static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
641{
642 struct ftrace_profile_page *pg;
643
644 pg = stat->pages = stat->start;
645
646 while (pg) {
647 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
648 pg->index = 0;
649 pg = pg->next;
650 }
651
652 memset(stat->hash, 0,
653 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
654}
655
656int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
657{
658 struct ftrace_profile_page *pg;
659 int functions;
660 int pages;
661 int i;
662
663 /* If we already allocated, do nothing */
664 if (stat->pages)
665 return 0;
666
667 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
668 if (!stat->pages)
669 return -ENOMEM;
670
671#ifdef CONFIG_DYNAMIC_FTRACE
672 functions = ftrace_update_tot_cnt;
673#else
674 /*
675 * We do not know the number of functions that exist because
676 * dynamic tracing is what counts them. With past experience
677 * we have around 20K functions. That should be more than enough.
678 * It is highly unlikely we will execute every function in
679 * the kernel.
680 */
681 functions = 20000;
682#endif
683
684 pg = stat->start = stat->pages;
685
686 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
687
688 for (i = 1; i < pages; i++) {
689 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
690 if (!pg->next)
691 goto out_free;
692 pg = pg->next;
693 }
694
695 return 0;
696
697 out_free:
698 pg = stat->start;
699 while (pg) {
700 unsigned long tmp = (unsigned long)pg;
701
702 pg = pg->next;
703 free_page(tmp);
704 }
705
706 stat->pages = NULL;
707 stat->start = NULL;
708
709 return -ENOMEM;
710}
711
712static int ftrace_profile_init_cpu(int cpu)
713{
714 struct ftrace_profile_stat *stat;
715 int size;
716
717 stat = &per_cpu(ftrace_profile_stats, cpu);
718
719 if (stat->hash) {
720 /* If the profile is already created, simply reset it */
721 ftrace_profile_reset(stat);
722 return 0;
723 }
724
725 /*
726 * We are profiling all functions, but usually only a few thousand
727 * functions are hit. We'll make a hash of 1024 items.
728 */
729 size = FTRACE_PROFILE_HASH_SIZE;
730
731 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
732
733 if (!stat->hash)
734 return -ENOMEM;
735
736 /* Preallocate the function profiling pages */
737 if (ftrace_profile_pages_init(stat) < 0) {
738 kfree(stat->hash);
739 stat->hash = NULL;
740 return -ENOMEM;
741 }
742
743 return 0;
744}
745
746static int ftrace_profile_init(void)
747{
748 int cpu;
749 int ret = 0;
750
751 for_each_possible_cpu(cpu) {
752 ret = ftrace_profile_init_cpu(cpu);
753 if (ret)
754 break;
755 }
756
757 return ret;
758}
759
760/* interrupts must be disabled */
761static struct ftrace_profile *
762ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
763{
764 struct ftrace_profile *rec;
765 struct hlist_head *hhd;
766 unsigned long key;
767
768 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
769 hhd = &stat->hash[key];
770
771 if (hlist_empty(hhd))
772 return NULL;
773
774 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
775 if (rec->ip == ip)
776 return rec;
777 }
778
779 return NULL;
780}
781
782static void ftrace_add_profile(struct ftrace_profile_stat *stat,
783 struct ftrace_profile *rec)
784{
785 unsigned long key;
786
787 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
788 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
789}
790
791/*
792 * The memory is already allocated, this simply finds a new record to use.
793 */
794static struct ftrace_profile *
795ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
796{
797 struct ftrace_profile *rec = NULL;
798
799 /* prevent recursion (from NMIs) */
800 if (atomic_inc_return(&stat->disabled) != 1)
801 goto out;
802
803 /*
804 * Try to find the function again since an NMI
805 * could have added it
806 */
807 rec = ftrace_find_profiled_func(stat, ip);
808 if (rec)
809 goto out;
810
811 if (stat->pages->index == PROFILES_PER_PAGE) {
812 if (!stat->pages->next)
813 goto out;
814 stat->pages = stat->pages->next;
815 }
816
817 rec = &stat->pages->records[stat->pages->index++];
818 rec->ip = ip;
819 ftrace_add_profile(stat, rec);
820
821 out:
822 atomic_dec(&stat->disabled);
823
824 return rec;
825}
826
827static void
828function_profile_call(unsigned long ip, unsigned long parent_ip,
829 struct ftrace_ops *ops, struct pt_regs *regs)
830{
831 struct ftrace_profile_stat *stat;
832 struct ftrace_profile *rec;
833 unsigned long flags;
834
835 if (!ftrace_profile_enabled)
836 return;
837
838 local_irq_save(flags);
839
840 stat = this_cpu_ptr(&ftrace_profile_stats);
841 if (!stat->hash || !ftrace_profile_enabled)
842 goto out;
843
844 rec = ftrace_find_profiled_func(stat, ip);
845 if (!rec) {
846 rec = ftrace_profile_alloc(stat, ip);
847 if (!rec)
848 goto out;
849 }
850
851 rec->counter++;
852 out:
853 local_irq_restore(flags);
854}
855
856#ifdef CONFIG_FUNCTION_GRAPH_TRACER
857static int profile_graph_entry(struct ftrace_graph_ent *trace)
858{
859 int index = trace->depth;
860
861 function_profile_call(trace->func, 0, NULL, NULL);
862
863 /* If function graph is shutting down, ret_stack can be NULL */
864 if (!current->ret_stack)
865 return 0;
866
867 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
868 current->ret_stack[index].subtime = 0;
869
870 return 1;
871}
872
873static void profile_graph_return(struct ftrace_graph_ret *trace)
874{
875 struct ftrace_profile_stat *stat;
876 unsigned long long calltime;
877 struct ftrace_profile *rec;
878 unsigned long flags;
879
880 local_irq_save(flags);
881 stat = this_cpu_ptr(&ftrace_profile_stats);
882 if (!stat->hash || !ftrace_profile_enabled)
883 goto out;
884
885 /* If the calltime was zero'd ignore it */
886 if (!trace->calltime)
887 goto out;
888
889 calltime = trace->rettime - trace->calltime;
890
891 if (!fgraph_graph_time) {
892 int index;
893
894 index = trace->depth;
895
896 /* Append this call time to the parent time to subtract */
897 if (index)
898 current->ret_stack[index - 1].subtime += calltime;
899
900 if (current->ret_stack[index].subtime < calltime)
901 calltime -= current->ret_stack[index].subtime;
902 else
903 calltime = 0;
904 }
905
906 rec = ftrace_find_profiled_func(stat, trace->func);
907 if (rec) {
908 rec->time += calltime;
909 rec->time_squared += calltime * calltime;
910 }
911
912 out:
913 local_irq_restore(flags);
914}
915
916static int register_ftrace_profiler(void)
917{
918 return register_ftrace_graph(&profile_graph_return,
919 &profile_graph_entry);
920}
921
922static void unregister_ftrace_profiler(void)
923{
924 unregister_ftrace_graph();
925}
926#else
927static struct ftrace_ops ftrace_profile_ops __read_mostly = {
928 .func = function_profile_call,
929 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
930 INIT_OPS_HASH(ftrace_profile_ops)
931};
932
933static int register_ftrace_profiler(void)
934{
935 return register_ftrace_function(&ftrace_profile_ops);
936}
937
938static void unregister_ftrace_profiler(void)
939{
940 unregister_ftrace_function(&ftrace_profile_ops);
941}
942#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
943
944static ssize_t
945ftrace_profile_write(struct file *filp, const char __user *ubuf,
946 size_t cnt, loff_t *ppos)
947{
948 unsigned long val;
949 int ret;
950
951 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
952 if (ret)
953 return ret;
954
955 val = !!val;
956
957 mutex_lock(&ftrace_profile_lock);
958 if (ftrace_profile_enabled ^ val) {
959 if (val) {
960 ret = ftrace_profile_init();
961 if (ret < 0) {
962 cnt = ret;
963 goto out;
964 }
965
966 ret = register_ftrace_profiler();
967 if (ret < 0) {
968 cnt = ret;
969 goto out;
970 }
971 ftrace_profile_enabled = 1;
972 } else {
973 ftrace_profile_enabled = 0;
974 /*
975 * unregister_ftrace_profiler calls stop_machine
976 * so this acts like an synchronize_sched.
977 */
978 unregister_ftrace_profiler();
979 }
980 }
981 out:
982 mutex_unlock(&ftrace_profile_lock);
983
984 *ppos += cnt;
985
986 return cnt;
987}
988
989static ssize_t
990ftrace_profile_read(struct file *filp, char __user *ubuf,
991 size_t cnt, loff_t *ppos)
992{
993 char buf[64]; /* big enough to hold a number */
994 int r;
995
996 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
997 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
998}
999
1000static const struct file_operations ftrace_profile_fops = {
1001 .open = tracing_open_generic,
1002 .read = ftrace_profile_read,
1003 .write = ftrace_profile_write,
1004 .llseek = default_llseek,
1005};
1006
1007/* used to initialize the real stat files */
1008static struct tracer_stat function_stats __initdata = {
1009 .name = "functions",
1010 .stat_start = function_stat_start,
1011 .stat_next = function_stat_next,
1012 .stat_cmp = function_stat_cmp,
1013 .stat_headers = function_stat_headers,
1014 .stat_show = function_stat_show
1015};
1016
1017static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1018{
1019 struct ftrace_profile_stat *stat;
1020 struct dentry *entry;
1021 char *name;
1022 int ret;
1023 int cpu;
1024
1025 for_each_possible_cpu(cpu) {
1026 stat = &per_cpu(ftrace_profile_stats, cpu);
1027
1028 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1029 if (!name) {
1030 /*
1031 * The files created are permanent, if something happens
1032 * we still do not free memory.
1033 */
1034 WARN(1,
1035 "Could not allocate stat file for cpu %d\n",
1036 cpu);
1037 return;
1038 }
1039 stat->stat = function_stats;
1040 stat->stat.name = name;
1041 ret = register_stat_tracer(&stat->stat);
1042 if (ret) {
1043 WARN(1,
1044 "Could not register function stat for cpu %d\n",
1045 cpu);
1046 kfree(name);
1047 return;
1048 }
1049 }
1050
1051 entry = tracefs_create_file("function_profile_enabled", 0644,
1052 d_tracer, NULL, &ftrace_profile_fops);
1053 if (!entry)
1054 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1055}
1056
1057#else /* CONFIG_FUNCTION_PROFILER */
1058static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1059{
1060}
1061#endif /* CONFIG_FUNCTION_PROFILER */
1062
1063static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1064
1065#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1066static int ftrace_graph_active;
1067#else
1068# define ftrace_graph_active 0
1069#endif
1070
1071#ifdef CONFIG_DYNAMIC_FTRACE
1072
1073static struct ftrace_ops *removed_ops;
1074
1075/*
1076 * Set when doing a global update, like enabling all recs or disabling them.
1077 * It is not set when just updating a single ftrace_ops.
1078 */
1079static bool update_all_ops;
1080
1081#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1082# error Dynamic ftrace depends on MCOUNT_RECORD
1083#endif
1084
1085struct ftrace_func_entry {
1086 struct hlist_node hlist;
1087 unsigned long ip;
1088};
1089
1090struct ftrace_func_probe {
1091 struct ftrace_probe_ops *probe_ops;
1092 struct ftrace_ops ops;
1093 struct trace_array *tr;
1094 struct list_head list;
1095 void *data;
1096 int ref;
1097};
1098
1099/*
1100 * We make these constant because no one should touch them,
1101 * but they are used as the default "empty hash", to avoid allocating
1102 * it all the time. These are in a read only section such that if
1103 * anyone does try to modify it, it will cause an exception.
1104 */
1105static const struct hlist_head empty_buckets[1];
1106static const struct ftrace_hash empty_hash = {
1107 .buckets = (struct hlist_head *)empty_buckets,
1108};
1109#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1110
1111static struct ftrace_ops global_ops = {
1112 .func = ftrace_stub,
1113 .local_hash.notrace_hash = EMPTY_HASH,
1114 .local_hash.filter_hash = EMPTY_HASH,
1115 INIT_OPS_HASH(global_ops)
1116 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1117 FTRACE_OPS_FL_INITIALIZED |
1118 FTRACE_OPS_FL_PID,
1119};
1120
1121/*
1122 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1123 */
1124struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1125{
1126 struct ftrace_ops *op = NULL;
1127
1128 /*
1129 * Some of the ops may be dynamically allocated,
1130 * they are freed after a synchronize_sched().
1131 */
1132 preempt_disable_notrace();
1133
1134 do_for_each_ftrace_op(op, ftrace_ops_list) {
1135 /*
1136 * This is to check for dynamically allocated trampolines.
1137 * Trampolines that are in kernel text will have
1138 * core_kernel_text() return true.
1139 */
1140 if (op->trampoline && op->trampoline_size)
1141 if (addr >= op->trampoline &&
1142 addr < op->trampoline + op->trampoline_size) {
1143 preempt_enable_notrace();
1144 return op;
1145 }
1146 } while_for_each_ftrace_op(op);
1147 preempt_enable_notrace();
1148
1149 return NULL;
1150}
1151
1152/*
1153 * This is used by __kernel_text_address() to return true if the
1154 * address is on a dynamically allocated trampoline that would
1155 * not return true for either core_kernel_text() or
1156 * is_module_text_address().
1157 */
1158bool is_ftrace_trampoline(unsigned long addr)
1159{
1160 return ftrace_ops_trampoline(addr) != NULL;
1161}
1162
1163struct ftrace_page {
1164 struct ftrace_page *next;
1165 struct dyn_ftrace *records;
1166 int index;
1167 int size;
1168};
1169
1170#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1171#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1172
1173/* estimate from running different kernels */
1174#define NR_TO_INIT 10000
1175
1176static struct ftrace_page *ftrace_pages_start;
1177static struct ftrace_page *ftrace_pages;
1178
1179static __always_inline unsigned long
1180ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1181{
1182 if (hash->size_bits > 0)
1183 return hash_long(ip, hash->size_bits);
1184
1185 return 0;
1186}
1187
1188/* Only use this function if ftrace_hash_empty() has already been tested */
1189static __always_inline struct ftrace_func_entry *
1190__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1191{
1192 unsigned long key;
1193 struct ftrace_func_entry *entry;
1194 struct hlist_head *hhd;
1195
1196 key = ftrace_hash_key(hash, ip);
1197 hhd = &hash->buckets[key];
1198
1199 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1200 if (entry->ip == ip)
1201 return entry;
1202 }
1203 return NULL;
1204}
1205
1206/**
1207 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1208 * @hash: The hash to look at
1209 * @ip: The instruction pointer to test
1210 *
1211 * Search a given @hash to see if a given instruction pointer (@ip)
1212 * exists in it.
1213 *
1214 * Returns the entry that holds the @ip if found. NULL otherwise.
1215 */
1216struct ftrace_func_entry *
1217ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1218{
1219 if (ftrace_hash_empty(hash))
1220 return NULL;
1221
1222 return __ftrace_lookup_ip(hash, ip);
1223}
1224
1225static void __add_hash_entry(struct ftrace_hash *hash,
1226 struct ftrace_func_entry *entry)
1227{
1228 struct hlist_head *hhd;
1229 unsigned long key;
1230
1231 key = ftrace_hash_key(hash, entry->ip);
1232 hhd = &hash->buckets[key];
1233 hlist_add_head(&entry->hlist, hhd);
1234 hash->count++;
1235}
1236
1237static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1238{
1239 struct ftrace_func_entry *entry;
1240
1241 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1242 if (!entry)
1243 return -ENOMEM;
1244
1245 entry->ip = ip;
1246 __add_hash_entry(hash, entry);
1247
1248 return 0;
1249}
1250
1251static void
1252free_hash_entry(struct ftrace_hash *hash,
1253 struct ftrace_func_entry *entry)
1254{
1255 hlist_del(&entry->hlist);
1256 kfree(entry);
1257 hash->count--;
1258}
1259
1260static void
1261remove_hash_entry(struct ftrace_hash *hash,
1262 struct ftrace_func_entry *entry)
1263{
1264 hlist_del_rcu(&entry->hlist);
1265 hash->count--;
1266}
1267
1268static void ftrace_hash_clear(struct ftrace_hash *hash)
1269{
1270 struct hlist_head *hhd;
1271 struct hlist_node *tn;
1272 struct ftrace_func_entry *entry;
1273 int size = 1 << hash->size_bits;
1274 int i;
1275
1276 if (!hash->count)
1277 return;
1278
1279 for (i = 0; i < size; i++) {
1280 hhd = &hash->buckets[i];
1281 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1282 free_hash_entry(hash, entry);
1283 }
1284 FTRACE_WARN_ON(hash->count);
1285}
1286
1287static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1288{
1289 list_del(&ftrace_mod->list);
1290 kfree(ftrace_mod->module);
1291 kfree(ftrace_mod->func);
1292 kfree(ftrace_mod);
1293}
1294
1295static void clear_ftrace_mod_list(struct list_head *head)
1296{
1297 struct ftrace_mod_load *p, *n;
1298
1299 /* stack tracer isn't supported yet */
1300 if (!head)
1301 return;
1302
1303 mutex_lock(&ftrace_lock);
1304 list_for_each_entry_safe(p, n, head, list)
1305 free_ftrace_mod(p);
1306 mutex_unlock(&ftrace_lock);
1307}
1308
1309static void free_ftrace_hash(struct ftrace_hash *hash)
1310{
1311 if (!hash || hash == EMPTY_HASH)
1312 return;
1313 ftrace_hash_clear(hash);
1314 kfree(hash->buckets);
1315 kfree(hash);
1316}
1317
1318static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1319{
1320 struct ftrace_hash *hash;
1321
1322 hash = container_of(rcu, struct ftrace_hash, rcu);
1323 free_ftrace_hash(hash);
1324}
1325
1326static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1327{
1328 if (!hash || hash == EMPTY_HASH)
1329 return;
1330 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1331}
1332
1333void ftrace_free_filter(struct ftrace_ops *ops)
1334{
1335 ftrace_ops_init(ops);
1336 free_ftrace_hash(ops->func_hash->filter_hash);
1337 free_ftrace_hash(ops->func_hash->notrace_hash);
1338}
1339
1340static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1341{
1342 struct ftrace_hash *hash;
1343 int size;
1344
1345 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1346 if (!hash)
1347 return NULL;
1348
1349 size = 1 << size_bits;
1350 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1351
1352 if (!hash->buckets) {
1353 kfree(hash);
1354 return NULL;
1355 }
1356
1357 hash->size_bits = size_bits;
1358
1359 return hash;
1360}
1361
1362
1363static int ftrace_add_mod(struct trace_array *tr,
1364 const char *func, const char *module,
1365 int enable)
1366{
1367 struct ftrace_mod_load *ftrace_mod;
1368 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1369
1370 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1371 if (!ftrace_mod)
1372 return -ENOMEM;
1373
1374 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1375 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1376 ftrace_mod->enable = enable;
1377
1378 if (!ftrace_mod->func || !ftrace_mod->module)
1379 goto out_free;
1380
1381 list_add(&ftrace_mod->list, mod_head);
1382
1383 return 0;
1384
1385 out_free:
1386 free_ftrace_mod(ftrace_mod);
1387
1388 return -ENOMEM;
1389}
1390
1391static struct ftrace_hash *
1392alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1393{
1394 struct ftrace_func_entry *entry;
1395 struct ftrace_hash *new_hash;
1396 int size;
1397 int ret;
1398 int i;
1399
1400 new_hash = alloc_ftrace_hash(size_bits);
1401 if (!new_hash)
1402 return NULL;
1403
1404 if (hash)
1405 new_hash->flags = hash->flags;
1406
1407 /* Empty hash? */
1408 if (ftrace_hash_empty(hash))
1409 return new_hash;
1410
1411 size = 1 << hash->size_bits;
1412 for (i = 0; i < size; i++) {
1413 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1414 ret = add_hash_entry(new_hash, entry->ip);
1415 if (ret < 0)
1416 goto free_hash;
1417 }
1418 }
1419
1420 FTRACE_WARN_ON(new_hash->count != hash->count);
1421
1422 return new_hash;
1423
1424 free_hash:
1425 free_ftrace_hash(new_hash);
1426 return NULL;
1427}
1428
1429static void
1430ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1431static void
1432ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1433
1434static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1435 struct ftrace_hash *new_hash);
1436
1437static struct ftrace_hash *
1438__ftrace_hash_move(struct ftrace_hash *src)
1439{
1440 struct ftrace_func_entry *entry;
1441 struct hlist_node *tn;
1442 struct hlist_head *hhd;
1443 struct ftrace_hash *new_hash;
1444 int size = src->count;
1445 int bits = 0;
1446 int i;
1447
1448 /*
1449 * If the new source is empty, just return the empty_hash.
1450 */
1451 if (ftrace_hash_empty(src))
1452 return EMPTY_HASH;
1453
1454 /*
1455 * Make the hash size about 1/2 the # found
1456 */
1457 for (size /= 2; size; size >>= 1)
1458 bits++;
1459
1460 /* Don't allocate too much */
1461 if (bits > FTRACE_HASH_MAX_BITS)
1462 bits = FTRACE_HASH_MAX_BITS;
1463
1464 new_hash = alloc_ftrace_hash(bits);
1465 if (!new_hash)
1466 return NULL;
1467
1468 new_hash->flags = src->flags;
1469
1470 size = 1 << src->size_bits;
1471 for (i = 0; i < size; i++) {
1472 hhd = &src->buckets[i];
1473 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1474 remove_hash_entry(src, entry);
1475 __add_hash_entry(new_hash, entry);
1476 }
1477 }
1478
1479 return new_hash;
1480}
1481
1482static int
1483ftrace_hash_move(struct ftrace_ops *ops, int enable,
1484 struct ftrace_hash **dst, struct ftrace_hash *src)
1485{
1486 struct ftrace_hash *new_hash;
1487 int ret;
1488
1489 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1490 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1491 return -EINVAL;
1492
1493 new_hash = __ftrace_hash_move(src);
1494 if (!new_hash)
1495 return -ENOMEM;
1496
1497 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1498 if (enable) {
1499 /* IPMODIFY should be updated only when filter_hash updating */
1500 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1501 if (ret < 0) {
1502 free_ftrace_hash(new_hash);
1503 return ret;
1504 }
1505 }
1506
1507 /*
1508 * Remove the current set, update the hash and add
1509 * them back.
1510 */
1511 ftrace_hash_rec_disable_modify(ops, enable);
1512
1513 rcu_assign_pointer(*dst, new_hash);
1514
1515 ftrace_hash_rec_enable_modify(ops, enable);
1516
1517 return 0;
1518}
1519
1520static bool hash_contains_ip(unsigned long ip,
1521 struct ftrace_ops_hash *hash)
1522{
1523 /*
1524 * The function record is a match if it exists in the filter
1525 * hash and not in the notrace hash. Note, an emty hash is
1526 * considered a match for the filter hash, but an empty
1527 * notrace hash is considered not in the notrace hash.
1528 */
1529 return (ftrace_hash_empty(hash->filter_hash) ||
1530 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1531 (ftrace_hash_empty(hash->notrace_hash) ||
1532 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1533}
1534
1535/*
1536 * Test the hashes for this ops to see if we want to call
1537 * the ops->func or not.
1538 *
1539 * It's a match if the ip is in the ops->filter_hash or
1540 * the filter_hash does not exist or is empty,
1541 * AND
1542 * the ip is not in the ops->notrace_hash.
1543 *
1544 * This needs to be called with preemption disabled as
1545 * the hashes are freed with call_rcu_sched().
1546 */
1547static int
1548ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1549{
1550 struct ftrace_ops_hash hash;
1551 int ret;
1552
1553#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1554 /*
1555 * There's a small race when adding ops that the ftrace handler
1556 * that wants regs, may be called without them. We can not
1557 * allow that handler to be called if regs is NULL.
1558 */
1559 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1560 return 0;
1561#endif
1562
1563 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1564 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1565
1566 if (hash_contains_ip(ip, &hash))
1567 ret = 1;
1568 else
1569 ret = 0;
1570
1571 return ret;
1572}
1573
1574/*
1575 * This is a double for. Do not use 'break' to break out of the loop,
1576 * you must use a goto.
1577 */
1578#define do_for_each_ftrace_rec(pg, rec) \
1579 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1580 int _____i; \
1581 for (_____i = 0; _____i < pg->index; _____i++) { \
1582 rec = &pg->records[_____i];
1583
1584#define while_for_each_ftrace_rec() \
1585 } \
1586 }
1587
1588
1589static int ftrace_cmp_recs(const void *a, const void *b)
1590{
1591 const struct dyn_ftrace *key = a;
1592 const struct dyn_ftrace *rec = b;
1593
1594 if (key->flags < rec->ip)
1595 return -1;
1596 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1597 return 1;
1598 return 0;
1599}
1600
1601/**
1602 * ftrace_location_range - return the first address of a traced location
1603 * if it touches the given ip range
1604 * @start: start of range to search.
1605 * @end: end of range to search (inclusive). @end points to the last byte
1606 * to check.
1607 *
1608 * Returns rec->ip if the related ftrace location is a least partly within
1609 * the given address range. That is, the first address of the instruction
1610 * that is either a NOP or call to the function tracer. It checks the ftrace
1611 * internal tables to determine if the address belongs or not.
1612 */
1613unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1614{
1615 struct ftrace_page *pg;
1616 struct dyn_ftrace *rec;
1617 struct dyn_ftrace key;
1618
1619 key.ip = start;
1620 key.flags = end; /* overload flags, as it is unsigned long */
1621
1622 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1623 if (end < pg->records[0].ip ||
1624 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1625 continue;
1626 rec = bsearch(&key, pg->records, pg->index,
1627 sizeof(struct dyn_ftrace),
1628 ftrace_cmp_recs);
1629 if (rec)
1630 return rec->ip;
1631 }
1632
1633 return 0;
1634}
1635
1636/**
1637 * ftrace_location - return true if the ip giving is a traced location
1638 * @ip: the instruction pointer to check
1639 *
1640 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1641 * That is, the instruction that is either a NOP or call to
1642 * the function tracer. It checks the ftrace internal tables to
1643 * determine if the address belongs or not.
1644 */
1645unsigned long ftrace_location(unsigned long ip)
1646{
1647 return ftrace_location_range(ip, ip);
1648}
1649
1650/**
1651 * ftrace_text_reserved - return true if range contains an ftrace location
1652 * @start: start of range to search
1653 * @end: end of range to search (inclusive). @end points to the last byte to check.
1654 *
1655 * Returns 1 if @start and @end contains a ftrace location.
1656 * That is, the instruction that is either a NOP or call to
1657 * the function tracer. It checks the ftrace internal tables to
1658 * determine if the address belongs or not.
1659 */
1660int ftrace_text_reserved(const void *start, const void *end)
1661{
1662 unsigned long ret;
1663
1664 ret = ftrace_location_range((unsigned long)start,
1665 (unsigned long)end);
1666
1667 return (int)!!ret;
1668}
1669
1670/* Test if ops registered to this rec needs regs */
1671static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1672{
1673 struct ftrace_ops *ops;
1674 bool keep_regs = false;
1675
1676 for (ops = ftrace_ops_list;
1677 ops != &ftrace_list_end; ops = ops->next) {
1678 /* pass rec in as regs to have non-NULL val */
1679 if (ftrace_ops_test(ops, rec->ip, rec)) {
1680 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1681 keep_regs = true;
1682 break;
1683 }
1684 }
1685 }
1686
1687 return keep_regs;
1688}
1689
1690static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1691 int filter_hash,
1692 bool inc)
1693{
1694 struct ftrace_hash *hash;
1695 struct ftrace_hash *other_hash;
1696 struct ftrace_page *pg;
1697 struct dyn_ftrace *rec;
1698 bool update = false;
1699 int count = 0;
1700 int all = false;
1701
1702 /* Only update if the ops has been registered */
1703 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1704 return false;
1705
1706 /*
1707 * In the filter_hash case:
1708 * If the count is zero, we update all records.
1709 * Otherwise we just update the items in the hash.
1710 *
1711 * In the notrace_hash case:
1712 * We enable the update in the hash.
1713 * As disabling notrace means enabling the tracing,
1714 * and enabling notrace means disabling, the inc variable
1715 * gets inversed.
1716 */
1717 if (filter_hash) {
1718 hash = ops->func_hash->filter_hash;
1719 other_hash = ops->func_hash->notrace_hash;
1720 if (ftrace_hash_empty(hash))
1721 all = true;
1722 } else {
1723 inc = !inc;
1724 hash = ops->func_hash->notrace_hash;
1725 other_hash = ops->func_hash->filter_hash;
1726 /*
1727 * If the notrace hash has no items,
1728 * then there's nothing to do.
1729 */
1730 if (ftrace_hash_empty(hash))
1731 return false;
1732 }
1733
1734 do_for_each_ftrace_rec(pg, rec) {
1735 int in_other_hash = 0;
1736 int in_hash = 0;
1737 int match = 0;
1738
1739 if (rec->flags & FTRACE_FL_DISABLED)
1740 continue;
1741
1742 if (all) {
1743 /*
1744 * Only the filter_hash affects all records.
1745 * Update if the record is not in the notrace hash.
1746 */
1747 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1748 match = 1;
1749 } else {
1750 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1751 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1752
1753 /*
1754 * If filter_hash is set, we want to match all functions
1755 * that are in the hash but not in the other hash.
1756 *
1757 * If filter_hash is not set, then we are decrementing.
1758 * That means we match anything that is in the hash
1759 * and also in the other_hash. That is, we need to turn
1760 * off functions in the other hash because they are disabled
1761 * by this hash.
1762 */
1763 if (filter_hash && in_hash && !in_other_hash)
1764 match = 1;
1765 else if (!filter_hash && in_hash &&
1766 (in_other_hash || ftrace_hash_empty(other_hash)))
1767 match = 1;
1768 }
1769 if (!match)
1770 continue;
1771
1772 if (inc) {
1773 rec->flags++;
1774 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1775 return false;
1776
1777 /*
1778 * If there's only a single callback registered to a
1779 * function, and the ops has a trampoline registered
1780 * for it, then we can call it directly.
1781 */
1782 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1783 rec->flags |= FTRACE_FL_TRAMP;
1784 else
1785 /*
1786 * If we are adding another function callback
1787 * to this function, and the previous had a
1788 * custom trampoline in use, then we need to go
1789 * back to the default trampoline.
1790 */
1791 rec->flags &= ~FTRACE_FL_TRAMP;
1792
1793 /*
1794 * If any ops wants regs saved for this function
1795 * then all ops will get saved regs.
1796 */
1797 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1798 rec->flags |= FTRACE_FL_REGS;
1799 } else {
1800 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1801 return false;
1802 rec->flags--;
1803
1804 /*
1805 * If the rec had REGS enabled and the ops that is
1806 * being removed had REGS set, then see if there is
1807 * still any ops for this record that wants regs.
1808 * If not, we can stop recording them.
1809 */
1810 if (ftrace_rec_count(rec) > 0 &&
1811 rec->flags & FTRACE_FL_REGS &&
1812 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1813 if (!test_rec_ops_needs_regs(rec))
1814 rec->flags &= ~FTRACE_FL_REGS;
1815 }
1816
1817 /*
1818 * If the rec had TRAMP enabled, then it needs to
1819 * be cleared. As TRAMP can only be enabled iff
1820 * there is only a single ops attached to it.
1821 * In otherwords, always disable it on decrementing.
1822 * In the future, we may set it if rec count is
1823 * decremented to one, and the ops that is left
1824 * has a trampoline.
1825 */
1826 rec->flags &= ~FTRACE_FL_TRAMP;
1827
1828 /*
1829 * flags will be cleared in ftrace_check_record()
1830 * if rec count is zero.
1831 */
1832 }
1833 count++;
1834
1835 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1836 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1837
1838 /* Shortcut, if we handled all records, we are done. */
1839 if (!all && count == hash->count)
1840 return update;
1841 } while_for_each_ftrace_rec();
1842
1843 return update;
1844}
1845
1846static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1847 int filter_hash)
1848{
1849 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1850}
1851
1852static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1853 int filter_hash)
1854{
1855 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1856}
1857
1858static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1859 int filter_hash, int inc)
1860{
1861 struct ftrace_ops *op;
1862
1863 __ftrace_hash_rec_update(ops, filter_hash, inc);
1864
1865 if (ops->func_hash != &global_ops.local_hash)
1866 return;
1867
1868 /*
1869 * If the ops shares the global_ops hash, then we need to update
1870 * all ops that are enabled and use this hash.
1871 */
1872 do_for_each_ftrace_op(op, ftrace_ops_list) {
1873 /* Already done */
1874 if (op == ops)
1875 continue;
1876 if (op->func_hash == &global_ops.local_hash)
1877 __ftrace_hash_rec_update(op, filter_hash, inc);
1878 } while_for_each_ftrace_op(op);
1879}
1880
1881static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1882 int filter_hash)
1883{
1884 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1885}
1886
1887static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1888 int filter_hash)
1889{
1890 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1891}
1892
1893/*
1894 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1895 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1896 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1897 * Note that old_hash and new_hash has below meanings
1898 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1899 * - If the hash is EMPTY_HASH, it hits nothing
1900 * - Anything else hits the recs which match the hash entries.
1901 */
1902static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1903 struct ftrace_hash *old_hash,
1904 struct ftrace_hash *new_hash)
1905{
1906 struct ftrace_page *pg;
1907 struct dyn_ftrace *rec, *end = NULL;
1908 int in_old, in_new;
1909
1910 /* Only update if the ops has been registered */
1911 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1912 return 0;
1913
1914 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1915 return 0;
1916
1917 /*
1918 * Since the IPMODIFY is a very address sensitive action, we do not
1919 * allow ftrace_ops to set all functions to new hash.
1920 */
1921 if (!new_hash || !old_hash)
1922 return -EINVAL;
1923
1924 /* Update rec->flags */
1925 do_for_each_ftrace_rec(pg, rec) {
1926
1927 if (rec->flags & FTRACE_FL_DISABLED)
1928 continue;
1929
1930 /* We need to update only differences of filter_hash */
1931 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1932 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1933 if (in_old == in_new)
1934 continue;
1935
1936 if (in_new) {
1937 /* New entries must ensure no others are using it */
1938 if (rec->flags & FTRACE_FL_IPMODIFY)
1939 goto rollback;
1940 rec->flags |= FTRACE_FL_IPMODIFY;
1941 } else /* Removed entry */
1942 rec->flags &= ~FTRACE_FL_IPMODIFY;
1943 } while_for_each_ftrace_rec();
1944
1945 return 0;
1946
1947rollback:
1948 end = rec;
1949
1950 /* Roll back what we did above */
1951 do_for_each_ftrace_rec(pg, rec) {
1952
1953 if (rec->flags & FTRACE_FL_DISABLED)
1954 continue;
1955
1956 if (rec == end)
1957 goto err_out;
1958
1959 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1960 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1961 if (in_old == in_new)
1962 continue;
1963
1964 if (in_new)
1965 rec->flags &= ~FTRACE_FL_IPMODIFY;
1966 else
1967 rec->flags |= FTRACE_FL_IPMODIFY;
1968 } while_for_each_ftrace_rec();
1969
1970err_out:
1971 return -EBUSY;
1972}
1973
1974static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1975{
1976 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1977
1978 if (ftrace_hash_empty(hash))
1979 hash = NULL;
1980
1981 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1982}
1983
1984/* Disabling always succeeds */
1985static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1986{
1987 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1988
1989 if (ftrace_hash_empty(hash))
1990 hash = NULL;
1991
1992 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1993}
1994
1995static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1996 struct ftrace_hash *new_hash)
1997{
1998 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1999
2000 if (ftrace_hash_empty(old_hash))
2001 old_hash = NULL;
2002
2003 if (ftrace_hash_empty(new_hash))
2004 new_hash = NULL;
2005
2006 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2007}
2008
2009static void print_ip_ins(const char *fmt, const unsigned char *p)
2010{
2011 int i;
2012
2013 printk(KERN_CONT "%s", fmt);
2014
2015 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
2016 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
2017}
2018
2019static struct ftrace_ops *
2020ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
2021static struct ftrace_ops *
2022ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
2023
2024enum ftrace_bug_type ftrace_bug_type;
2025const void *ftrace_expected;
2026
2027static void print_bug_type(void)
2028{
2029 switch (ftrace_bug_type) {
2030 case FTRACE_BUG_UNKNOWN:
2031 break;
2032 case FTRACE_BUG_INIT:
2033 pr_info("Initializing ftrace call sites\n");
2034 break;
2035 case FTRACE_BUG_NOP:
2036 pr_info("Setting ftrace call site to NOP\n");
2037 break;
2038 case FTRACE_BUG_CALL:
2039 pr_info("Setting ftrace call site to call ftrace function\n");
2040 break;
2041 case FTRACE_BUG_UPDATE:
2042 pr_info("Updating ftrace call site to call a different ftrace function\n");
2043 break;
2044 }
2045}
2046
2047/**
2048 * ftrace_bug - report and shutdown function tracer
2049 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2050 * @rec: The record that failed
2051 *
2052 * The arch code that enables or disables the function tracing
2053 * can call ftrace_bug() when it has detected a problem in
2054 * modifying the code. @failed should be one of either:
2055 * EFAULT - if the problem happens on reading the @ip address
2056 * EINVAL - if what is read at @ip is not what was expected
2057 * EPERM - if the problem happens on writting to the @ip address
2058 */
2059void ftrace_bug(int failed, struct dyn_ftrace *rec)
2060{
2061 unsigned long ip = rec ? rec->ip : 0;
2062
2063 switch (failed) {
2064 case -EFAULT:
2065 FTRACE_WARN_ON_ONCE(1);
2066 pr_info("ftrace faulted on modifying ");
2067 print_ip_sym(ip);
2068 break;
2069 case -EINVAL:
2070 FTRACE_WARN_ON_ONCE(1);
2071 pr_info("ftrace failed to modify ");
2072 print_ip_sym(ip);
2073 print_ip_ins(" actual: ", (unsigned char *)ip);
2074 pr_cont("\n");
2075 if (ftrace_expected) {
2076 print_ip_ins(" expected: ", ftrace_expected);
2077 pr_cont("\n");
2078 }
2079 break;
2080 case -EPERM:
2081 FTRACE_WARN_ON_ONCE(1);
2082 pr_info("ftrace faulted on writing ");
2083 print_ip_sym(ip);
2084 break;
2085 default:
2086 FTRACE_WARN_ON_ONCE(1);
2087 pr_info("ftrace faulted on unknown error ");
2088 print_ip_sym(ip);
2089 }
2090 print_bug_type();
2091 if (rec) {
2092 struct ftrace_ops *ops = NULL;
2093
2094 pr_info("ftrace record flags: %lx\n", rec->flags);
2095 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2096 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2097 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2098 ops = ftrace_find_tramp_ops_any(rec);
2099 if (ops) {
2100 do {
2101 pr_cont("\ttramp: %pS (%pS)",
2102 (void *)ops->trampoline,
2103 (void *)ops->func);
2104 ops = ftrace_find_tramp_ops_next(rec, ops);
2105 } while (ops);
2106 } else
2107 pr_cont("\ttramp: ERROR!");
2108
2109 }
2110 ip = ftrace_get_addr_curr(rec);
2111 pr_cont("\n expected tramp: %lx\n", ip);
2112 }
2113}
2114
2115static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2116{
2117 unsigned long flag = 0UL;
2118
2119 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2120
2121 if (rec->flags & FTRACE_FL_DISABLED)
2122 return FTRACE_UPDATE_IGNORE;
2123
2124 /*
2125 * If we are updating calls:
2126 *
2127 * If the record has a ref count, then we need to enable it
2128 * because someone is using it.
2129 *
2130 * Otherwise we make sure its disabled.
2131 *
2132 * If we are disabling calls, then disable all records that
2133 * are enabled.
2134 */
2135 if (enable && ftrace_rec_count(rec))
2136 flag = FTRACE_FL_ENABLED;
2137
2138 /*
2139 * If enabling and the REGS flag does not match the REGS_EN, or
2140 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2141 * this record. Set flags to fail the compare against ENABLED.
2142 */
2143 if (flag) {
2144 if (!(rec->flags & FTRACE_FL_REGS) !=
2145 !(rec->flags & FTRACE_FL_REGS_EN))
2146 flag |= FTRACE_FL_REGS;
2147
2148 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2149 !(rec->flags & FTRACE_FL_TRAMP_EN))
2150 flag |= FTRACE_FL_TRAMP;
2151 }
2152
2153 /* If the state of this record hasn't changed, then do nothing */
2154 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2155 return FTRACE_UPDATE_IGNORE;
2156
2157 if (flag) {
2158 /* Save off if rec is being enabled (for return value) */
2159 flag ^= rec->flags & FTRACE_FL_ENABLED;
2160
2161 if (update) {
2162 rec->flags |= FTRACE_FL_ENABLED;
2163 if (flag & FTRACE_FL_REGS) {
2164 if (rec->flags & FTRACE_FL_REGS)
2165 rec->flags |= FTRACE_FL_REGS_EN;
2166 else
2167 rec->flags &= ~FTRACE_FL_REGS_EN;
2168 }
2169 if (flag & FTRACE_FL_TRAMP) {
2170 if (rec->flags & FTRACE_FL_TRAMP)
2171 rec->flags |= FTRACE_FL_TRAMP_EN;
2172 else
2173 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2174 }
2175 }
2176
2177 /*
2178 * If this record is being updated from a nop, then
2179 * return UPDATE_MAKE_CALL.
2180 * Otherwise,
2181 * return UPDATE_MODIFY_CALL to tell the caller to convert
2182 * from the save regs, to a non-save regs function or
2183 * vice versa, or from a trampoline call.
2184 */
2185 if (flag & FTRACE_FL_ENABLED) {
2186 ftrace_bug_type = FTRACE_BUG_CALL;
2187 return FTRACE_UPDATE_MAKE_CALL;
2188 }
2189
2190 ftrace_bug_type = FTRACE_BUG_UPDATE;
2191 return FTRACE_UPDATE_MODIFY_CALL;
2192 }
2193
2194 if (update) {
2195 /* If there's no more users, clear all flags */
2196 if (!ftrace_rec_count(rec))
2197 rec->flags = 0;
2198 else
2199 /*
2200 * Just disable the record, but keep the ops TRAMP
2201 * and REGS states. The _EN flags must be disabled though.
2202 */
2203 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2204 FTRACE_FL_REGS_EN);
2205 }
2206
2207 ftrace_bug_type = FTRACE_BUG_NOP;
2208 return FTRACE_UPDATE_MAKE_NOP;
2209}
2210
2211/**
2212 * ftrace_update_record, set a record that now is tracing or not
2213 * @rec: the record to update
2214 * @enable: set to 1 if the record is tracing, zero to force disable
2215 *
2216 * The records that represent all functions that can be traced need
2217 * to be updated when tracing has been enabled.
2218 */
2219int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2220{
2221 return ftrace_check_record(rec, enable, 1);
2222}
2223
2224/**
2225 * ftrace_test_record, check if the record has been enabled or not
2226 * @rec: the record to test
2227 * @enable: set to 1 to check if enabled, 0 if it is disabled
2228 *
2229 * The arch code may need to test if a record is already set to
2230 * tracing to determine how to modify the function code that it
2231 * represents.
2232 */
2233int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2234{
2235 return ftrace_check_record(rec, enable, 0);
2236}
2237
2238static struct ftrace_ops *
2239ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2240{
2241 struct ftrace_ops *op;
2242 unsigned long ip = rec->ip;
2243
2244 do_for_each_ftrace_op(op, ftrace_ops_list) {
2245
2246 if (!op->trampoline)
2247 continue;
2248
2249 if (hash_contains_ip(ip, op->func_hash))
2250 return op;
2251 } while_for_each_ftrace_op(op);
2252
2253 return NULL;
2254}
2255
2256static struct ftrace_ops *
2257ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2258 struct ftrace_ops *op)
2259{
2260 unsigned long ip = rec->ip;
2261
2262 while_for_each_ftrace_op(op) {
2263
2264 if (!op->trampoline)
2265 continue;
2266
2267 if (hash_contains_ip(ip, op->func_hash))
2268 return op;
2269 }
2270
2271 return NULL;
2272}
2273
2274static struct ftrace_ops *
2275ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2276{
2277 struct ftrace_ops *op;
2278 unsigned long ip = rec->ip;
2279
2280 /*
2281 * Need to check removed ops first.
2282 * If they are being removed, and this rec has a tramp,
2283 * and this rec is in the ops list, then it would be the
2284 * one with the tramp.
2285 */
2286 if (removed_ops) {
2287 if (hash_contains_ip(ip, &removed_ops->old_hash))
2288 return removed_ops;
2289 }
2290
2291 /*
2292 * Need to find the current trampoline for a rec.
2293 * Now, a trampoline is only attached to a rec if there
2294 * was a single 'ops' attached to it. But this can be called
2295 * when we are adding another op to the rec or removing the
2296 * current one. Thus, if the op is being added, we can
2297 * ignore it because it hasn't attached itself to the rec
2298 * yet.
2299 *
2300 * If an ops is being modified (hooking to different functions)
2301 * then we don't care about the new functions that are being
2302 * added, just the old ones (that are probably being removed).
2303 *
2304 * If we are adding an ops to a function that already is using
2305 * a trampoline, it needs to be removed (trampolines are only
2306 * for single ops connected), then an ops that is not being
2307 * modified also needs to be checked.
2308 */
2309 do_for_each_ftrace_op(op, ftrace_ops_list) {
2310
2311 if (!op->trampoline)
2312 continue;
2313
2314 /*
2315 * If the ops is being added, it hasn't gotten to
2316 * the point to be removed from this tree yet.
2317 */
2318 if (op->flags & FTRACE_OPS_FL_ADDING)
2319 continue;
2320
2321
2322 /*
2323 * If the ops is being modified and is in the old
2324 * hash, then it is probably being removed from this
2325 * function.
2326 */
2327 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2328 hash_contains_ip(ip, &op->old_hash))
2329 return op;
2330 /*
2331 * If the ops is not being added or modified, and it's
2332 * in its normal filter hash, then this must be the one
2333 * we want!
2334 */
2335 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2336 hash_contains_ip(ip, op->func_hash))
2337 return op;
2338
2339 } while_for_each_ftrace_op(op);
2340
2341 return NULL;
2342}
2343
2344static struct ftrace_ops *
2345ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2346{
2347 struct ftrace_ops *op;
2348 unsigned long ip = rec->ip;
2349
2350 do_for_each_ftrace_op(op, ftrace_ops_list) {
2351 /* pass rec in as regs to have non-NULL val */
2352 if (hash_contains_ip(ip, op->func_hash))
2353 return op;
2354 } while_for_each_ftrace_op(op);
2355
2356 return NULL;
2357}
2358
2359/**
2360 * ftrace_get_addr_new - Get the call address to set to
2361 * @rec: The ftrace record descriptor
2362 *
2363 * If the record has the FTRACE_FL_REGS set, that means that it
2364 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2365 * is not not set, then it wants to convert to the normal callback.
2366 *
2367 * Returns the address of the trampoline to set to
2368 */
2369unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2370{
2371 struct ftrace_ops *ops;
2372
2373 /* Trampolines take precedence over regs */
2374 if (rec->flags & FTRACE_FL_TRAMP) {
2375 ops = ftrace_find_tramp_ops_new(rec);
2376 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2377 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2378 (void *)rec->ip, (void *)rec->ip, rec->flags);
2379 /* Ftrace is shutting down, return anything */
2380 return (unsigned long)FTRACE_ADDR;
2381 }
2382 return ops->trampoline;
2383 }
2384
2385 if (rec->flags & FTRACE_FL_REGS)
2386 return (unsigned long)FTRACE_REGS_ADDR;
2387 else
2388 return (unsigned long)FTRACE_ADDR;
2389}
2390
2391/**
2392 * ftrace_get_addr_curr - Get the call address that is already there
2393 * @rec: The ftrace record descriptor
2394 *
2395 * The FTRACE_FL_REGS_EN is set when the record already points to
2396 * a function that saves all the regs. Basically the '_EN' version
2397 * represents the current state of the function.
2398 *
2399 * Returns the address of the trampoline that is currently being called
2400 */
2401unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2402{
2403 struct ftrace_ops *ops;
2404
2405 /* Trampolines take precedence over regs */
2406 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2407 ops = ftrace_find_tramp_ops_curr(rec);
2408 if (FTRACE_WARN_ON(!ops)) {
2409 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2410 (void *)rec->ip, (void *)rec->ip);
2411 /* Ftrace is shutting down, return anything */
2412 return (unsigned long)FTRACE_ADDR;
2413 }
2414 return ops->trampoline;
2415 }
2416
2417 if (rec->flags & FTRACE_FL_REGS_EN)
2418 return (unsigned long)FTRACE_REGS_ADDR;
2419 else
2420 return (unsigned long)FTRACE_ADDR;
2421}
2422
2423static int
2424__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2425{
2426 unsigned long ftrace_old_addr;
2427 unsigned long ftrace_addr;
2428 int ret;
2429
2430 ftrace_addr = ftrace_get_addr_new(rec);
2431
2432 /* This needs to be done before we call ftrace_update_record */
2433 ftrace_old_addr = ftrace_get_addr_curr(rec);
2434
2435 ret = ftrace_update_record(rec, enable);
2436
2437 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2438
2439 switch (ret) {
2440 case FTRACE_UPDATE_IGNORE:
2441 return 0;
2442
2443 case FTRACE_UPDATE_MAKE_CALL:
2444 ftrace_bug_type = FTRACE_BUG_CALL;
2445 return ftrace_make_call(rec, ftrace_addr);
2446
2447 case FTRACE_UPDATE_MAKE_NOP:
2448 ftrace_bug_type = FTRACE_BUG_NOP;
2449 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2450
2451 case FTRACE_UPDATE_MODIFY_CALL:
2452 ftrace_bug_type = FTRACE_BUG_UPDATE;
2453 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2454 }
2455
2456 return -1; /* unknow ftrace bug */
2457}
2458
2459void __weak ftrace_replace_code(int enable)
2460{
2461 struct dyn_ftrace *rec;
2462 struct ftrace_page *pg;
2463 int failed;
2464
2465 if (unlikely(ftrace_disabled))
2466 return;
2467
2468 do_for_each_ftrace_rec(pg, rec) {
2469
2470 if (rec->flags & FTRACE_FL_DISABLED)
2471 continue;
2472
2473 failed = __ftrace_replace_code(rec, enable);
2474 if (failed) {
2475 ftrace_bug(failed, rec);
2476 /* Stop processing */
2477 return;
2478 }
2479 } while_for_each_ftrace_rec();
2480}
2481
2482struct ftrace_rec_iter {
2483 struct ftrace_page *pg;
2484 int index;
2485};
2486
2487/**
2488 * ftrace_rec_iter_start, start up iterating over traced functions
2489 *
2490 * Returns an iterator handle that is used to iterate over all
2491 * the records that represent address locations where functions
2492 * are traced.
2493 *
2494 * May return NULL if no records are available.
2495 */
2496struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2497{
2498 /*
2499 * We only use a single iterator.
2500 * Protected by the ftrace_lock mutex.
2501 */
2502 static struct ftrace_rec_iter ftrace_rec_iter;
2503 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2504
2505 iter->pg = ftrace_pages_start;
2506 iter->index = 0;
2507
2508 /* Could have empty pages */
2509 while (iter->pg && !iter->pg->index)
2510 iter->pg = iter->pg->next;
2511
2512 if (!iter->pg)
2513 return NULL;
2514
2515 return iter;
2516}
2517
2518/**
2519 * ftrace_rec_iter_next, get the next record to process.
2520 * @iter: The handle to the iterator.
2521 *
2522 * Returns the next iterator after the given iterator @iter.
2523 */
2524struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2525{
2526 iter->index++;
2527
2528 if (iter->index >= iter->pg->index) {
2529 iter->pg = iter->pg->next;
2530 iter->index = 0;
2531
2532 /* Could have empty pages */
2533 while (iter->pg && !iter->pg->index)
2534 iter->pg = iter->pg->next;
2535 }
2536
2537 if (!iter->pg)
2538 return NULL;
2539
2540 return iter;
2541}
2542
2543/**
2544 * ftrace_rec_iter_record, get the record at the iterator location
2545 * @iter: The current iterator location
2546 *
2547 * Returns the record that the current @iter is at.
2548 */
2549struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2550{
2551 return &iter->pg->records[iter->index];
2552}
2553
2554static int
2555ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2556{
2557 int ret;
2558
2559 if (unlikely(ftrace_disabled))
2560 return 0;
2561
2562 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2563 if (ret) {
2564 ftrace_bug_type = FTRACE_BUG_INIT;
2565 ftrace_bug(ret, rec);
2566 return 0;
2567 }
2568 return 1;
2569}
2570
2571/*
2572 * archs can override this function if they must do something
2573 * before the modifying code is performed.
2574 */
2575int __weak ftrace_arch_code_modify_prepare(void)
2576{
2577 return 0;
2578}
2579
2580/*
2581 * archs can override this function if they must do something
2582 * after the modifying code is performed.
2583 */
2584int __weak ftrace_arch_code_modify_post_process(void)
2585{
2586 return 0;
2587}
2588
2589void ftrace_modify_all_code(int command)
2590{
2591 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2592 int err = 0;
2593
2594 /*
2595 * If the ftrace_caller calls a ftrace_ops func directly,
2596 * we need to make sure that it only traces functions it
2597 * expects to trace. When doing the switch of functions,
2598 * we need to update to the ftrace_ops_list_func first
2599 * before the transition between old and new calls are set,
2600 * as the ftrace_ops_list_func will check the ops hashes
2601 * to make sure the ops are having the right functions
2602 * traced.
2603 */
2604 if (update) {
2605 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2606 if (FTRACE_WARN_ON(err))
2607 return;
2608 }
2609
2610 if (command & FTRACE_UPDATE_CALLS)
2611 ftrace_replace_code(1);
2612 else if (command & FTRACE_DISABLE_CALLS)
2613 ftrace_replace_code(0);
2614
2615 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2616 function_trace_op = set_function_trace_op;
2617 smp_wmb();
2618 /* If irqs are disabled, we are in stop machine */
2619 if (!irqs_disabled())
2620 smp_call_function(ftrace_sync_ipi, NULL, 1);
2621 err = ftrace_update_ftrace_func(ftrace_trace_function);
2622 if (FTRACE_WARN_ON(err))
2623 return;
2624 }
2625
2626 if (command & FTRACE_START_FUNC_RET)
2627 err = ftrace_enable_ftrace_graph_caller();
2628 else if (command & FTRACE_STOP_FUNC_RET)
2629 err = ftrace_disable_ftrace_graph_caller();
2630 FTRACE_WARN_ON(err);
2631}
2632
2633static int __ftrace_modify_code(void *data)
2634{
2635 int *command = data;
2636
2637 ftrace_modify_all_code(*command);
2638
2639 return 0;
2640}
2641
2642/**
2643 * ftrace_run_stop_machine, go back to the stop machine method
2644 * @command: The command to tell ftrace what to do
2645 *
2646 * If an arch needs to fall back to the stop machine method, the
2647 * it can call this function.
2648 */
2649void ftrace_run_stop_machine(int command)
2650{
2651 stop_machine(__ftrace_modify_code, &command, NULL);
2652}
2653
2654/**
2655 * arch_ftrace_update_code, modify the code to trace or not trace
2656 * @command: The command that needs to be done
2657 *
2658 * Archs can override this function if it does not need to
2659 * run stop_machine() to modify code.
2660 */
2661void __weak arch_ftrace_update_code(int command)
2662{
2663 ftrace_run_stop_machine(command);
2664}
2665
2666static void ftrace_run_update_code(int command)
2667{
2668 int ret;
2669
2670 ret = ftrace_arch_code_modify_prepare();
2671 FTRACE_WARN_ON(ret);
2672 if (ret)
2673 return;
2674
2675 /*
2676 * By default we use stop_machine() to modify the code.
2677 * But archs can do what ever they want as long as it
2678 * is safe. The stop_machine() is the safest, but also
2679 * produces the most overhead.
2680 */
2681 arch_ftrace_update_code(command);
2682
2683 ret = ftrace_arch_code_modify_post_process();
2684 FTRACE_WARN_ON(ret);
2685}
2686
2687static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2688 struct ftrace_ops_hash *old_hash)
2689{
2690 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2691 ops->old_hash.filter_hash = old_hash->filter_hash;
2692 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2693 ftrace_run_update_code(command);
2694 ops->old_hash.filter_hash = NULL;
2695 ops->old_hash.notrace_hash = NULL;
2696 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2697}
2698
2699static ftrace_func_t saved_ftrace_func;
2700static int ftrace_start_up;
2701
2702void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2703{
2704}
2705
2706static void ftrace_startup_enable(int command)
2707{
2708 if (saved_ftrace_func != ftrace_trace_function) {
2709 saved_ftrace_func = ftrace_trace_function;
2710 command |= FTRACE_UPDATE_TRACE_FUNC;
2711 }
2712
2713 if (!command || !ftrace_enabled)
2714 return;
2715
2716 ftrace_run_update_code(command);
2717}
2718
2719static void ftrace_startup_all(int command)
2720{
2721 update_all_ops = true;
2722 ftrace_startup_enable(command);
2723 update_all_ops = false;
2724}
2725
2726static int ftrace_startup(struct ftrace_ops *ops, int command)
2727{
2728 int ret;
2729
2730 if (unlikely(ftrace_disabled))
2731 return -ENODEV;
2732
2733 ret = __register_ftrace_function(ops);
2734 if (ret)
2735 return ret;
2736
2737 ftrace_start_up++;
2738
2739 /*
2740 * Note that ftrace probes uses this to start up
2741 * and modify functions it will probe. But we still
2742 * set the ADDING flag for modification, as probes
2743 * do not have trampolines. If they add them in the
2744 * future, then the probes will need to distinguish
2745 * between adding and updating probes.
2746 */
2747 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2748
2749 ret = ftrace_hash_ipmodify_enable(ops);
2750 if (ret < 0) {
2751 /* Rollback registration process */
2752 __unregister_ftrace_function(ops);
2753 ftrace_start_up--;
2754 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2755 return ret;
2756 }
2757
2758 if (ftrace_hash_rec_enable(ops, 1))
2759 command |= FTRACE_UPDATE_CALLS;
2760
2761 ftrace_startup_enable(command);
2762
2763 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2764
2765 return 0;
2766}
2767
2768static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2769{
2770 int ret;
2771
2772 if (unlikely(ftrace_disabled))
2773 return -ENODEV;
2774
2775 ret = __unregister_ftrace_function(ops);
2776 if (ret)
2777 return ret;
2778
2779 ftrace_start_up--;
2780 /*
2781 * Just warn in case of unbalance, no need to kill ftrace, it's not
2782 * critical but the ftrace_call callers may be never nopped again after
2783 * further ftrace uses.
2784 */
2785 WARN_ON_ONCE(ftrace_start_up < 0);
2786
2787 /* Disabling ipmodify never fails */
2788 ftrace_hash_ipmodify_disable(ops);
2789
2790 if (ftrace_hash_rec_disable(ops, 1))
2791 command |= FTRACE_UPDATE_CALLS;
2792
2793 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2794
2795 if (saved_ftrace_func != ftrace_trace_function) {
2796 saved_ftrace_func = ftrace_trace_function;
2797 command |= FTRACE_UPDATE_TRACE_FUNC;
2798 }
2799
2800 if (!command || !ftrace_enabled) {
2801 /*
2802 * If these are dynamic or per_cpu ops, they still
2803 * need their data freed. Since, function tracing is
2804 * not currently active, we can just free them
2805 * without synchronizing all CPUs.
2806 */
2807 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2808 goto free_ops;
2809
2810 return 0;
2811 }
2812
2813 /*
2814 * If the ops uses a trampoline, then it needs to be
2815 * tested first on update.
2816 */
2817 ops->flags |= FTRACE_OPS_FL_REMOVING;
2818 removed_ops = ops;
2819
2820 /* The trampoline logic checks the old hashes */
2821 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2822 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2823
2824 ftrace_run_update_code(command);
2825
2826 /*
2827 * If there's no more ops registered with ftrace, run a
2828 * sanity check to make sure all rec flags are cleared.
2829 */
2830 if (rcu_dereference_protected(ftrace_ops_list,
2831 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2832 struct ftrace_page *pg;
2833 struct dyn_ftrace *rec;
2834
2835 do_for_each_ftrace_rec(pg, rec) {
2836 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2837 pr_warn(" %pS flags:%lx\n",
2838 (void *)rec->ip, rec->flags);
2839 } while_for_each_ftrace_rec();
2840 }
2841
2842 ops->old_hash.filter_hash = NULL;
2843 ops->old_hash.notrace_hash = NULL;
2844
2845 removed_ops = NULL;
2846 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2847
2848 /*
2849 * Dynamic ops may be freed, we must make sure that all
2850 * callers are done before leaving this function.
2851 * The same goes for freeing the per_cpu data of the per_cpu
2852 * ops.
2853 */
2854 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2855 /*
2856 * We need to do a hard force of sched synchronization.
2857 * This is because we use preempt_disable() to do RCU, but
2858 * the function tracers can be called where RCU is not watching
2859 * (like before user_exit()). We can not rely on the RCU
2860 * infrastructure to do the synchronization, thus we must do it
2861 * ourselves.
2862 */
2863 schedule_on_each_cpu(ftrace_sync);
2864
2865 /*
2866 * When the kernel is preeptive, tasks can be preempted
2867 * while on a ftrace trampoline. Just scheduling a task on
2868 * a CPU is not good enough to flush them. Calling
2869 * synchornize_rcu_tasks() will wait for those tasks to
2870 * execute and either schedule voluntarily or enter user space.
2871 */
2872 if (IS_ENABLED(CONFIG_PREEMPT))
2873 synchronize_rcu_tasks();
2874
2875 free_ops:
2876 arch_ftrace_trampoline_free(ops);
2877 }
2878
2879 return 0;
2880}
2881
2882static void ftrace_startup_sysctl(void)
2883{
2884 int command;
2885
2886 if (unlikely(ftrace_disabled))
2887 return;
2888
2889 /* Force update next time */
2890 saved_ftrace_func = NULL;
2891 /* ftrace_start_up is true if we want ftrace running */
2892 if (ftrace_start_up) {
2893 command = FTRACE_UPDATE_CALLS;
2894 if (ftrace_graph_active)
2895 command |= FTRACE_START_FUNC_RET;
2896 ftrace_startup_enable(command);
2897 }
2898}
2899
2900static void ftrace_shutdown_sysctl(void)
2901{
2902 int command;
2903
2904 if (unlikely(ftrace_disabled))
2905 return;
2906
2907 /* ftrace_start_up is true if ftrace is running */
2908 if (ftrace_start_up) {
2909 command = FTRACE_DISABLE_CALLS;
2910 if (ftrace_graph_active)
2911 command |= FTRACE_STOP_FUNC_RET;
2912 ftrace_run_update_code(command);
2913 }
2914}
2915
2916static u64 ftrace_update_time;
2917unsigned long ftrace_update_tot_cnt;
2918
2919static inline int ops_traces_mod(struct ftrace_ops *ops)
2920{
2921 /*
2922 * Filter_hash being empty will default to trace module.
2923 * But notrace hash requires a test of individual module functions.
2924 */
2925 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2926 ftrace_hash_empty(ops->func_hash->notrace_hash);
2927}
2928
2929/*
2930 * Check if the current ops references the record.
2931 *
2932 * If the ops traces all functions, then it was already accounted for.
2933 * If the ops does not trace the current record function, skip it.
2934 * If the ops ignores the function via notrace filter, skip it.
2935 */
2936static inline bool
2937ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2938{
2939 /* If ops isn't enabled, ignore it */
2940 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2941 return 0;
2942
2943 /* If ops traces all then it includes this function */
2944 if (ops_traces_mod(ops))
2945 return 1;
2946
2947 /* The function must be in the filter */
2948 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2949 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2950 return 0;
2951
2952 /* If in notrace hash, we ignore it too */
2953 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2954 return 0;
2955
2956 return 1;
2957}
2958
2959static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2960{
2961 struct ftrace_page *pg;
2962 struct dyn_ftrace *p;
2963 u64 start, stop;
2964 unsigned long update_cnt = 0;
2965 unsigned long rec_flags = 0;
2966 int i;
2967
2968 start = ftrace_now(raw_smp_processor_id());
2969
2970 /*
2971 * When a module is loaded, this function is called to convert
2972 * the calls to mcount in its text to nops, and also to create
2973 * an entry in the ftrace data. Now, if ftrace is activated
2974 * after this call, but before the module sets its text to
2975 * read-only, the modification of enabling ftrace can fail if
2976 * the read-only is done while ftrace is converting the calls.
2977 * To prevent this, the module's records are set as disabled
2978 * and will be enabled after the call to set the module's text
2979 * to read-only.
2980 */
2981 if (mod)
2982 rec_flags |= FTRACE_FL_DISABLED;
2983
2984 for (pg = new_pgs; pg; pg = pg->next) {
2985
2986 for (i = 0; i < pg->index; i++) {
2987
2988 /* If something went wrong, bail without enabling anything */
2989 if (unlikely(ftrace_disabled))
2990 return -1;
2991
2992 p = &pg->records[i];
2993 p->flags = rec_flags;
2994
2995 /*
2996 * Do the initial record conversion from mcount jump
2997 * to the NOP instructions.
2998 */
2999 if (!ftrace_code_disable(mod, p))
3000 break;
3001
3002 update_cnt++;
3003 }
3004 }
3005
3006 stop = ftrace_now(raw_smp_processor_id());
3007 ftrace_update_time = stop - start;
3008 ftrace_update_tot_cnt += update_cnt;
3009
3010 return 0;
3011}
3012
3013static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3014{
3015 int order;
3016 int cnt;
3017
3018 if (WARN_ON(!count))
3019 return -EINVAL;
3020
3021 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3022
3023 /*
3024 * We want to fill as much as possible. No more than a page
3025 * may be empty.
3026 */
3027 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3028 order--;
3029
3030 again:
3031 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3032
3033 if (!pg->records) {
3034 /* if we can't allocate this size, try something smaller */
3035 if (!order)
3036 return -ENOMEM;
3037 order >>= 1;
3038 goto again;
3039 }
3040
3041 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3042 pg->size = cnt;
3043
3044 if (cnt > count)
3045 cnt = count;
3046
3047 return cnt;
3048}
3049
3050static struct ftrace_page *
3051ftrace_allocate_pages(unsigned long num_to_init)
3052{
3053 struct ftrace_page *start_pg;
3054 struct ftrace_page *pg;
3055 int order;
3056 int cnt;
3057
3058 if (!num_to_init)
3059 return 0;
3060
3061 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3062 if (!pg)
3063 return NULL;
3064
3065 /*
3066 * Try to allocate as much as possible in one continues
3067 * location that fills in all of the space. We want to
3068 * waste as little space as possible.
3069 */
3070 for (;;) {
3071 cnt = ftrace_allocate_records(pg, num_to_init);
3072 if (cnt < 0)
3073 goto free_pages;
3074
3075 num_to_init -= cnt;
3076 if (!num_to_init)
3077 break;
3078
3079 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3080 if (!pg->next)
3081 goto free_pages;
3082
3083 pg = pg->next;
3084 }
3085
3086 return start_pg;
3087
3088 free_pages:
3089 pg = start_pg;
3090 while (pg) {
3091 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3092 free_pages((unsigned long)pg->records, order);
3093 start_pg = pg->next;
3094 kfree(pg);
3095 pg = start_pg;
3096 }
3097 pr_info("ftrace: FAILED to allocate memory for functions\n");
3098 return NULL;
3099}
3100
3101#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3102
3103struct ftrace_iterator {
3104 loff_t pos;
3105 loff_t func_pos;
3106 loff_t mod_pos;
3107 struct ftrace_page *pg;
3108 struct dyn_ftrace *func;
3109 struct ftrace_func_probe *probe;
3110 struct ftrace_func_entry *probe_entry;
3111 struct trace_parser parser;
3112 struct ftrace_hash *hash;
3113 struct ftrace_ops *ops;
3114 struct trace_array *tr;
3115 struct list_head *mod_list;
3116 int pidx;
3117 int idx;
3118 unsigned flags;
3119};
3120
3121static void *
3122t_probe_next(struct seq_file *m, loff_t *pos)
3123{
3124 struct ftrace_iterator *iter = m->private;
3125 struct trace_array *tr = iter->ops->private;
3126 struct list_head *func_probes;
3127 struct ftrace_hash *hash;
3128 struct list_head *next;
3129 struct hlist_node *hnd = NULL;
3130 struct hlist_head *hhd;
3131 int size;
3132
3133 (*pos)++;
3134 iter->pos = *pos;
3135
3136 if (!tr)
3137 return NULL;
3138
3139 func_probes = &tr->func_probes;
3140 if (list_empty(func_probes))
3141 return NULL;
3142
3143 if (!iter->probe) {
3144 next = func_probes->next;
3145 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3146 }
3147
3148 if (iter->probe_entry)
3149 hnd = &iter->probe_entry->hlist;
3150
3151 hash = iter->probe->ops.func_hash->filter_hash;
3152 size = 1 << hash->size_bits;
3153
3154 retry:
3155 if (iter->pidx >= size) {
3156 if (iter->probe->list.next == func_probes)
3157 return NULL;
3158 next = iter->probe->list.next;
3159 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3160 hash = iter->probe->ops.func_hash->filter_hash;
3161 size = 1 << hash->size_bits;
3162 iter->pidx = 0;
3163 }
3164
3165 hhd = &hash->buckets[iter->pidx];
3166
3167 if (hlist_empty(hhd)) {
3168 iter->pidx++;
3169 hnd = NULL;
3170 goto retry;
3171 }
3172
3173 if (!hnd)
3174 hnd = hhd->first;
3175 else {
3176 hnd = hnd->next;
3177 if (!hnd) {
3178 iter->pidx++;
3179 goto retry;
3180 }
3181 }
3182
3183 if (WARN_ON_ONCE(!hnd))
3184 return NULL;
3185
3186 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3187
3188 return iter;
3189}
3190
3191static void *t_probe_start(struct seq_file *m, loff_t *pos)
3192{
3193 struct ftrace_iterator *iter = m->private;
3194 void *p = NULL;
3195 loff_t l;
3196
3197 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3198 return NULL;
3199
3200 if (iter->mod_pos > *pos)
3201 return NULL;
3202
3203 iter->probe = NULL;
3204 iter->probe_entry = NULL;
3205 iter->pidx = 0;
3206 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3207 p = t_probe_next(m, &l);
3208 if (!p)
3209 break;
3210 }
3211 if (!p)
3212 return NULL;
3213
3214 /* Only set this if we have an item */
3215 iter->flags |= FTRACE_ITER_PROBE;
3216
3217 return iter;
3218}
3219
3220static int
3221t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3222{
3223 struct ftrace_func_entry *probe_entry;
3224 struct ftrace_probe_ops *probe_ops;
3225 struct ftrace_func_probe *probe;
3226
3227 probe = iter->probe;
3228 probe_entry = iter->probe_entry;
3229
3230 if (WARN_ON_ONCE(!probe || !probe_entry))
3231 return -EIO;
3232
3233 probe_ops = probe->probe_ops;
3234
3235 if (probe_ops->print)
3236 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3237
3238 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3239 (void *)probe_ops->func);
3240
3241 return 0;
3242}
3243
3244static void *
3245t_mod_next(struct seq_file *m, loff_t *pos)
3246{
3247 struct ftrace_iterator *iter = m->private;
3248 struct trace_array *tr = iter->tr;
3249
3250 (*pos)++;
3251 iter->pos = *pos;
3252
3253 iter->mod_list = iter->mod_list->next;
3254
3255 if (iter->mod_list == &tr->mod_trace ||
3256 iter->mod_list == &tr->mod_notrace) {
3257 iter->flags &= ~FTRACE_ITER_MOD;
3258 return NULL;
3259 }
3260
3261 iter->mod_pos = *pos;
3262
3263 return iter;
3264}
3265
3266static void *t_mod_start(struct seq_file *m, loff_t *pos)
3267{
3268 struct ftrace_iterator *iter = m->private;
3269 void *p = NULL;
3270 loff_t l;
3271
3272 if (iter->func_pos > *pos)
3273 return NULL;
3274
3275 iter->mod_pos = iter->func_pos;
3276
3277 /* probes are only available if tr is set */
3278 if (!iter->tr)
3279 return NULL;
3280
3281 for (l = 0; l <= (*pos - iter->func_pos); ) {
3282 p = t_mod_next(m, &l);
3283 if (!p)
3284 break;
3285 }
3286 if (!p) {
3287 iter->flags &= ~FTRACE_ITER_MOD;
3288 return t_probe_start(m, pos);
3289 }
3290
3291 /* Only set this if we have an item */
3292 iter->flags |= FTRACE_ITER_MOD;
3293
3294 return iter;
3295}
3296
3297static int
3298t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3299{
3300 struct ftrace_mod_load *ftrace_mod;
3301 struct trace_array *tr = iter->tr;
3302
3303 if (WARN_ON_ONCE(!iter->mod_list) ||
3304 iter->mod_list == &tr->mod_trace ||
3305 iter->mod_list == &tr->mod_notrace)
3306 return -EIO;
3307
3308 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3309
3310 if (ftrace_mod->func)
3311 seq_printf(m, "%s", ftrace_mod->func);
3312 else
3313 seq_putc(m, '*');
3314
3315 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3316
3317 return 0;
3318}
3319
3320static void *
3321t_func_next(struct seq_file *m, loff_t *pos)
3322{
3323 struct ftrace_iterator *iter = m->private;
3324 struct dyn_ftrace *rec = NULL;
3325
3326 (*pos)++;
3327
3328 retry:
3329 if (iter->idx >= iter->pg->index) {
3330 if (iter->pg->next) {
3331 iter->pg = iter->pg->next;
3332 iter->idx = 0;
3333 goto retry;
3334 }
3335 } else {
3336 rec = &iter->pg->records[iter->idx++];
3337 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3338 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3339
3340 ((iter->flags & FTRACE_ITER_ENABLED) &&
3341 !(rec->flags & FTRACE_FL_ENABLED))) {
3342
3343 rec = NULL;
3344 goto retry;
3345 }
3346 }
3347
3348 if (!rec)
3349 return NULL;
3350
3351 iter->pos = iter->func_pos = *pos;
3352 iter->func = rec;
3353
3354 return iter;
3355}
3356
3357static void *
3358t_next(struct seq_file *m, void *v, loff_t *pos)
3359{
3360 struct ftrace_iterator *iter = m->private;
3361 loff_t l = *pos; /* t_probe_start() must use original pos */
3362 void *ret;
3363
3364 if (unlikely(ftrace_disabled))
3365 return NULL;
3366
3367 if (iter->flags & FTRACE_ITER_PROBE)
3368 return t_probe_next(m, pos);
3369
3370 if (iter->flags & FTRACE_ITER_MOD)
3371 return t_mod_next(m, pos);
3372
3373 if (iter->flags & FTRACE_ITER_PRINTALL) {
3374 /* next must increment pos, and t_probe_start does not */
3375 (*pos)++;
3376 return t_mod_start(m, &l);
3377 }
3378
3379 ret = t_func_next(m, pos);
3380
3381 if (!ret)
3382 return t_mod_start(m, &l);
3383
3384 return ret;
3385}
3386
3387static void reset_iter_read(struct ftrace_iterator *iter)
3388{
3389 iter->pos = 0;
3390 iter->func_pos = 0;
3391 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3392}
3393
3394static void *t_start(struct seq_file *m, loff_t *pos)
3395{
3396 struct ftrace_iterator *iter = m->private;
3397 void *p = NULL;
3398 loff_t l;
3399
3400 mutex_lock(&ftrace_lock);
3401
3402 if (unlikely(ftrace_disabled))
3403 return NULL;
3404
3405 /*
3406 * If an lseek was done, then reset and start from beginning.
3407 */
3408 if (*pos < iter->pos)
3409 reset_iter_read(iter);
3410
3411 /*
3412 * For set_ftrace_filter reading, if we have the filter
3413 * off, we can short cut and just print out that all
3414 * functions are enabled.
3415 */
3416 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3417 ftrace_hash_empty(iter->hash)) {
3418 iter->func_pos = 1; /* Account for the message */
3419 if (*pos > 0)
3420 return t_mod_start(m, pos);
3421 iter->flags |= FTRACE_ITER_PRINTALL;
3422 /* reset in case of seek/pread */
3423 iter->flags &= ~FTRACE_ITER_PROBE;
3424 return iter;
3425 }
3426
3427 if (iter->flags & FTRACE_ITER_MOD)
3428 return t_mod_start(m, pos);
3429
3430 /*
3431 * Unfortunately, we need to restart at ftrace_pages_start
3432 * every time we let go of the ftrace_mutex. This is because
3433 * those pointers can change without the lock.
3434 */
3435 iter->pg = ftrace_pages_start;
3436 iter->idx = 0;
3437 for (l = 0; l <= *pos; ) {
3438 p = t_func_next(m, &l);
3439 if (!p)
3440 break;
3441 }
3442
3443 if (!p)
3444 return t_mod_start(m, pos);
3445
3446 return iter;
3447}
3448
3449static void t_stop(struct seq_file *m, void *p)
3450{
3451 mutex_unlock(&ftrace_lock);
3452}
3453
3454void * __weak
3455arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3456{
3457 return NULL;
3458}
3459
3460static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3461 struct dyn_ftrace *rec)
3462{
3463 void *ptr;
3464
3465 ptr = arch_ftrace_trampoline_func(ops, rec);
3466 if (ptr)
3467 seq_printf(m, " ->%pS", ptr);
3468}
3469
3470static int t_show(struct seq_file *m, void *v)
3471{
3472 struct ftrace_iterator *iter = m->private;
3473 struct dyn_ftrace *rec;
3474
3475 if (iter->flags & FTRACE_ITER_PROBE)
3476 return t_probe_show(m, iter);
3477
3478 if (iter->flags & FTRACE_ITER_MOD)
3479 return t_mod_show(m, iter);
3480
3481 if (iter->flags & FTRACE_ITER_PRINTALL) {
3482 if (iter->flags & FTRACE_ITER_NOTRACE)
3483 seq_puts(m, "#### no functions disabled ####\n");
3484 else
3485 seq_puts(m, "#### all functions enabled ####\n");
3486 return 0;
3487 }
3488
3489 rec = iter->func;
3490
3491 if (!rec)
3492 return 0;
3493
3494 seq_printf(m, "%ps", (void *)rec->ip);
3495 if (iter->flags & FTRACE_ITER_ENABLED) {
3496 struct ftrace_ops *ops;
3497
3498 seq_printf(m, " (%ld)%s%s",
3499 ftrace_rec_count(rec),
3500 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3501 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3502 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3503 ops = ftrace_find_tramp_ops_any(rec);
3504 if (ops) {
3505 do {
3506 seq_printf(m, "\ttramp: %pS (%pS)",
3507 (void *)ops->trampoline,
3508 (void *)ops->func);
3509 add_trampoline_func(m, ops, rec);
3510 ops = ftrace_find_tramp_ops_next(rec, ops);
3511 } while (ops);
3512 } else
3513 seq_puts(m, "\ttramp: ERROR!");
3514 } else {
3515 add_trampoline_func(m, NULL, rec);
3516 }
3517 }
3518
3519 seq_putc(m, '\n');
3520
3521 return 0;
3522}
3523
3524static const struct seq_operations show_ftrace_seq_ops = {
3525 .start = t_start,
3526 .next = t_next,
3527 .stop = t_stop,
3528 .show = t_show,
3529};
3530
3531static int
3532ftrace_avail_open(struct inode *inode, struct file *file)
3533{
3534 struct ftrace_iterator *iter;
3535
3536 if (unlikely(ftrace_disabled))
3537 return -ENODEV;
3538
3539 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3540 if (!iter)
3541 return -ENOMEM;
3542
3543 iter->pg = ftrace_pages_start;
3544 iter->ops = &global_ops;
3545
3546 return 0;
3547}
3548
3549static int
3550ftrace_enabled_open(struct inode *inode, struct file *file)
3551{
3552 struct ftrace_iterator *iter;
3553
3554 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3555 if (!iter)
3556 return -ENOMEM;
3557
3558 iter->pg = ftrace_pages_start;
3559 iter->flags = FTRACE_ITER_ENABLED;
3560 iter->ops = &global_ops;
3561
3562 return 0;
3563}
3564
3565/**
3566 * ftrace_regex_open - initialize function tracer filter files
3567 * @ops: The ftrace_ops that hold the hash filters
3568 * @flag: The type of filter to process
3569 * @inode: The inode, usually passed in to your open routine
3570 * @file: The file, usually passed in to your open routine
3571 *
3572 * ftrace_regex_open() initializes the filter files for the
3573 * @ops. Depending on @flag it may process the filter hash or
3574 * the notrace hash of @ops. With this called from the open
3575 * routine, you can use ftrace_filter_write() for the write
3576 * routine if @flag has FTRACE_ITER_FILTER set, or
3577 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3578 * tracing_lseek() should be used as the lseek routine, and
3579 * release must call ftrace_regex_release().
3580 */
3581int
3582ftrace_regex_open(struct ftrace_ops *ops, int flag,
3583 struct inode *inode, struct file *file)
3584{
3585 struct ftrace_iterator *iter;
3586 struct ftrace_hash *hash;
3587 struct list_head *mod_head;
3588 struct trace_array *tr = ops->private;
3589 int ret = 0;
3590
3591 ftrace_ops_init(ops);
3592
3593 if (unlikely(ftrace_disabled))
3594 return -ENODEV;
3595
3596 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3597 if (!iter)
3598 return -ENOMEM;
3599
3600 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3601 kfree(iter);
3602 return -ENOMEM;
3603 }
3604
3605 iter->ops = ops;
3606 iter->flags = flag;
3607 iter->tr = tr;
3608
3609 mutex_lock(&ops->func_hash->regex_lock);
3610
3611 if (flag & FTRACE_ITER_NOTRACE) {
3612 hash = ops->func_hash->notrace_hash;
3613 mod_head = tr ? &tr->mod_notrace : NULL;
3614 } else {
3615 hash = ops->func_hash->filter_hash;
3616 mod_head = tr ? &tr->mod_trace : NULL;
3617 }
3618
3619 iter->mod_list = mod_head;
3620
3621 if (file->f_mode & FMODE_WRITE) {
3622 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3623
3624 if (file->f_flags & O_TRUNC) {
3625 iter->hash = alloc_ftrace_hash(size_bits);
3626 clear_ftrace_mod_list(mod_head);
3627 } else {
3628 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3629 }
3630
3631 if (!iter->hash) {
3632 trace_parser_put(&iter->parser);
3633 kfree(iter);
3634 ret = -ENOMEM;
3635 goto out_unlock;
3636 }
3637 } else
3638 iter->hash = hash;
3639
3640 if (file->f_mode & FMODE_READ) {
3641 iter->pg = ftrace_pages_start;
3642
3643 ret = seq_open(file, &show_ftrace_seq_ops);
3644 if (!ret) {
3645 struct seq_file *m = file->private_data;
3646 m->private = iter;
3647 } else {
3648 /* Failed */
3649 free_ftrace_hash(iter->hash);
3650 trace_parser_put(&iter->parser);
3651 kfree(iter);
3652 }
3653 } else
3654 file->private_data = iter;
3655
3656 out_unlock:
3657 mutex_unlock(&ops->func_hash->regex_lock);
3658
3659 return ret;
3660}
3661
3662static int
3663ftrace_filter_open(struct inode *inode, struct file *file)
3664{
3665 struct ftrace_ops *ops = inode->i_private;
3666
3667 return ftrace_regex_open(ops,
3668 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3669 inode, file);
3670}
3671
3672static int
3673ftrace_notrace_open(struct inode *inode, struct file *file)
3674{
3675 struct ftrace_ops *ops = inode->i_private;
3676
3677 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3678 inode, file);
3679}
3680
3681/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3682struct ftrace_glob {
3683 char *search;
3684 unsigned len;
3685 int type;
3686};
3687
3688/*
3689 * If symbols in an architecture don't correspond exactly to the user-visible
3690 * name of what they represent, it is possible to define this function to
3691 * perform the necessary adjustments.
3692*/
3693char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3694{
3695 return str;
3696}
3697
3698static int ftrace_match(char *str, struct ftrace_glob *g)
3699{
3700 int matched = 0;
3701 int slen;
3702
3703 str = arch_ftrace_match_adjust(str, g->search);
3704
3705 switch (g->type) {
3706 case MATCH_FULL:
3707 if (strcmp(str, g->search) == 0)
3708 matched = 1;
3709 break;
3710 case MATCH_FRONT_ONLY:
3711 if (strncmp(str, g->search, g->len) == 0)
3712 matched = 1;
3713 break;
3714 case MATCH_MIDDLE_ONLY:
3715 if (strstr(str, g->search))
3716 matched = 1;
3717 break;
3718 case MATCH_END_ONLY:
3719 slen = strlen(str);
3720 if (slen >= g->len &&
3721 memcmp(str + slen - g->len, g->search, g->len) == 0)
3722 matched = 1;
3723 break;
3724 case MATCH_GLOB:
3725 if (glob_match(g->search, str))
3726 matched = 1;
3727 break;
3728 }
3729
3730 return matched;
3731}
3732
3733static int
3734enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3735{
3736 struct ftrace_func_entry *entry;
3737 int ret = 0;
3738
3739 entry = ftrace_lookup_ip(hash, rec->ip);
3740 if (clear_filter) {
3741 /* Do nothing if it doesn't exist */
3742 if (!entry)
3743 return 0;
3744
3745 free_hash_entry(hash, entry);
3746 } else {
3747 /* Do nothing if it exists */
3748 if (entry)
3749 return 0;
3750
3751 ret = add_hash_entry(hash, rec->ip);
3752 }
3753 return ret;
3754}
3755
3756static int
3757ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3758 struct ftrace_glob *mod_g, int exclude_mod)
3759{
3760 char str[KSYM_SYMBOL_LEN];
3761 char *modname;
3762
3763 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3764
3765 if (mod_g) {
3766 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3767
3768 /* blank module name to match all modules */
3769 if (!mod_g->len) {
3770 /* blank module globbing: modname xor exclude_mod */
3771 if (!exclude_mod != !modname)
3772 goto func_match;
3773 return 0;
3774 }
3775
3776 /*
3777 * exclude_mod is set to trace everything but the given
3778 * module. If it is set and the module matches, then
3779 * return 0. If it is not set, and the module doesn't match
3780 * also return 0. Otherwise, check the function to see if
3781 * that matches.
3782 */
3783 if (!mod_matches == !exclude_mod)
3784 return 0;
3785func_match:
3786 /* blank search means to match all funcs in the mod */
3787 if (!func_g->len)
3788 return 1;
3789 }
3790
3791 return ftrace_match(str, func_g);
3792}
3793
3794static int
3795match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3796{
3797 struct ftrace_page *pg;
3798 struct dyn_ftrace *rec;
3799 struct ftrace_glob func_g = { .type = MATCH_FULL };
3800 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3801 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3802 int exclude_mod = 0;
3803 int found = 0;
3804 int ret;
3805 int clear_filter = 0;
3806
3807 if (func) {
3808 func_g.type = filter_parse_regex(func, len, &func_g.search,
3809 &clear_filter);
3810 func_g.len = strlen(func_g.search);
3811 }
3812
3813 if (mod) {
3814 mod_g.type = filter_parse_regex(mod, strlen(mod),
3815 &mod_g.search, &exclude_mod);
3816 mod_g.len = strlen(mod_g.search);
3817 }
3818
3819 mutex_lock(&ftrace_lock);
3820
3821 if (unlikely(ftrace_disabled))
3822 goto out_unlock;
3823
3824 do_for_each_ftrace_rec(pg, rec) {
3825
3826 if (rec->flags & FTRACE_FL_DISABLED)
3827 continue;
3828
3829 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3830 ret = enter_record(hash, rec, clear_filter);
3831 if (ret < 0) {
3832 found = ret;
3833 goto out_unlock;
3834 }
3835 found = 1;
3836 }
3837 } while_for_each_ftrace_rec();
3838 out_unlock:
3839 mutex_unlock(&ftrace_lock);
3840
3841 return found;
3842}
3843
3844static int
3845ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3846{
3847 return match_records(hash, buff, len, NULL);
3848}
3849
3850static void ftrace_ops_update_code(struct ftrace_ops *ops,
3851 struct ftrace_ops_hash *old_hash)
3852{
3853 struct ftrace_ops *op;
3854
3855 if (!ftrace_enabled)
3856 return;
3857
3858 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3859 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3860 return;
3861 }
3862
3863 /*
3864 * If this is the shared global_ops filter, then we need to
3865 * check if there is another ops that shares it, is enabled.
3866 * If so, we still need to run the modify code.
3867 */
3868 if (ops->func_hash != &global_ops.local_hash)
3869 return;
3870
3871 do_for_each_ftrace_op(op, ftrace_ops_list) {
3872 if (op->func_hash == &global_ops.local_hash &&
3873 op->flags & FTRACE_OPS_FL_ENABLED) {
3874 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3875 /* Only need to do this once */
3876 return;
3877 }
3878 } while_for_each_ftrace_op(op);
3879}
3880
3881static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3882 struct ftrace_hash **orig_hash,
3883 struct ftrace_hash *hash,
3884 int enable)
3885{
3886 struct ftrace_ops_hash old_hash_ops;
3887 struct ftrace_hash *old_hash;
3888 int ret;
3889
3890 old_hash = *orig_hash;
3891 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3892 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3893 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3894 if (!ret) {
3895 ftrace_ops_update_code(ops, &old_hash_ops);
3896 free_ftrace_hash_rcu(old_hash);
3897 }
3898 return ret;
3899}
3900
3901static bool module_exists(const char *module)
3902{
3903 /* All modules have the symbol __this_module */
3904 const char this_mod[] = "__this_module";
3905 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
3906 unsigned long val;
3907 int n;
3908
3909 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
3910
3911 if (n > sizeof(modname) - 1)
3912 return false;
3913
3914 val = module_kallsyms_lookup_name(modname);
3915 return val != 0;
3916}
3917
3918static int cache_mod(struct trace_array *tr,
3919 const char *func, char *module, int enable)
3920{
3921 struct ftrace_mod_load *ftrace_mod, *n;
3922 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3923 int ret;
3924
3925 mutex_lock(&ftrace_lock);
3926
3927 /* We do not cache inverse filters */
3928 if (func[0] == '!') {
3929 func++;
3930 ret = -EINVAL;
3931
3932 /* Look to remove this hash */
3933 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3934 if (strcmp(ftrace_mod->module, module) != 0)
3935 continue;
3936
3937 /* no func matches all */
3938 if (strcmp(func, "*") == 0 ||
3939 (ftrace_mod->func &&
3940 strcmp(ftrace_mod->func, func) == 0)) {
3941 ret = 0;
3942 free_ftrace_mod(ftrace_mod);
3943 continue;
3944 }
3945 }
3946 goto out;
3947 }
3948
3949 ret = -EINVAL;
3950 /* We only care about modules that have not been loaded yet */
3951 if (module_exists(module))
3952 goto out;
3953
3954 /* Save this string off, and execute it when the module is loaded */
3955 ret = ftrace_add_mod(tr, func, module, enable);
3956 out:
3957 mutex_unlock(&ftrace_lock);
3958
3959 return ret;
3960}
3961
3962static int
3963ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3964 int reset, int enable);
3965
3966#ifdef CONFIG_MODULES
3967static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3968 char *mod, bool enable)
3969{
3970 struct ftrace_mod_load *ftrace_mod, *n;
3971 struct ftrace_hash **orig_hash, *new_hash;
3972 LIST_HEAD(process_mods);
3973 char *func;
3974 int ret;
3975
3976 mutex_lock(&ops->func_hash->regex_lock);
3977
3978 if (enable)
3979 orig_hash = &ops->func_hash->filter_hash;
3980 else
3981 orig_hash = &ops->func_hash->notrace_hash;
3982
3983 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
3984 *orig_hash);
3985 if (!new_hash)
3986 goto out; /* warn? */
3987
3988 mutex_lock(&ftrace_lock);
3989
3990 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3991
3992 if (strcmp(ftrace_mod->module, mod) != 0)
3993 continue;
3994
3995 if (ftrace_mod->func)
3996 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
3997 else
3998 func = kstrdup("*", GFP_KERNEL);
3999
4000 if (!func) /* warn? */
4001 continue;
4002
4003 list_del(&ftrace_mod->list);
4004 list_add(&ftrace_mod->list, &process_mods);
4005
4006 /* Use the newly allocated func, as it may be "*" */
4007 kfree(ftrace_mod->func);
4008 ftrace_mod->func = func;
4009 }
4010
4011 mutex_unlock(&ftrace_lock);
4012
4013 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4014
4015 func = ftrace_mod->func;
4016
4017 /* Grabs ftrace_lock, which is why we have this extra step */
4018 match_records(new_hash, func, strlen(func), mod);
4019 free_ftrace_mod(ftrace_mod);
4020 }
4021
4022 if (enable && list_empty(head))
4023 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4024
4025 mutex_lock(&ftrace_lock);
4026
4027 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4028 new_hash, enable);
4029 mutex_unlock(&ftrace_lock);
4030
4031 out:
4032 mutex_unlock(&ops->func_hash->regex_lock);
4033
4034 free_ftrace_hash(new_hash);
4035}
4036
4037static void process_cached_mods(const char *mod_name)
4038{
4039 struct trace_array *tr;
4040 char *mod;
4041
4042 mod = kstrdup(mod_name, GFP_KERNEL);
4043 if (!mod)
4044 return;
4045
4046 mutex_lock(&trace_types_lock);
4047 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4048 if (!list_empty(&tr->mod_trace))
4049 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4050 if (!list_empty(&tr->mod_notrace))
4051 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4052 }
4053 mutex_unlock(&trace_types_lock);
4054
4055 kfree(mod);
4056}
4057#endif
4058
4059/*
4060 * We register the module command as a template to show others how
4061 * to register the a command as well.
4062 */
4063
4064static int
4065ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4066 char *func_orig, char *cmd, char *module, int enable)
4067{
4068 char *func;
4069 int ret;
4070
4071 /* match_records() modifies func, and we need the original */
4072 func = kstrdup(func_orig, GFP_KERNEL);
4073 if (!func)
4074 return -ENOMEM;
4075
4076 /*
4077 * cmd == 'mod' because we only registered this func
4078 * for the 'mod' ftrace_func_command.
4079 * But if you register one func with multiple commands,
4080 * you can tell which command was used by the cmd
4081 * parameter.
4082 */
4083 ret = match_records(hash, func, strlen(func), module);
4084 kfree(func);
4085
4086 if (!ret)
4087 return cache_mod(tr, func_orig, module, enable);
4088 if (ret < 0)
4089 return ret;
4090 return 0;
4091}
4092
4093static struct ftrace_func_command ftrace_mod_cmd = {
4094 .name = "mod",
4095 .func = ftrace_mod_callback,
4096};
4097
4098static int __init ftrace_mod_cmd_init(void)
4099{
4100 return register_ftrace_command(&ftrace_mod_cmd);
4101}
4102core_initcall(ftrace_mod_cmd_init);
4103
4104static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4105 struct ftrace_ops *op, struct pt_regs *pt_regs)
4106{
4107 struct ftrace_probe_ops *probe_ops;
4108 struct ftrace_func_probe *probe;
4109
4110 probe = container_of(op, struct ftrace_func_probe, ops);
4111 probe_ops = probe->probe_ops;
4112
4113 /*
4114 * Disable preemption for these calls to prevent a RCU grace
4115 * period. This syncs the hash iteration and freeing of items
4116 * on the hash. rcu_read_lock is too dangerous here.
4117 */
4118 preempt_disable_notrace();
4119 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4120 preempt_enable_notrace();
4121}
4122
4123struct ftrace_func_map {
4124 struct ftrace_func_entry entry;
4125 void *data;
4126};
4127
4128struct ftrace_func_mapper {
4129 struct ftrace_hash hash;
4130};
4131
4132/**
4133 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4134 *
4135 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4136 */
4137struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4138{
4139 struct ftrace_hash *hash;
4140
4141 /*
4142 * The mapper is simply a ftrace_hash, but since the entries
4143 * in the hash are not ftrace_func_entry type, we define it
4144 * as a separate structure.
4145 */
4146 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4147 return (struct ftrace_func_mapper *)hash;
4148}
4149
4150/**
4151 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4152 * @mapper: The mapper that has the ip maps
4153 * @ip: the instruction pointer to find the data for
4154 *
4155 * Returns the data mapped to @ip if found otherwise NULL. The return
4156 * is actually the address of the mapper data pointer. The address is
4157 * returned for use cases where the data is no bigger than a long, and
4158 * the user can use the data pointer as its data instead of having to
4159 * allocate more memory for the reference.
4160 */
4161void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4162 unsigned long ip)
4163{
4164 struct ftrace_func_entry *entry;
4165 struct ftrace_func_map *map;
4166
4167 entry = ftrace_lookup_ip(&mapper->hash, ip);
4168 if (!entry)
4169 return NULL;
4170
4171 map = (struct ftrace_func_map *)entry;
4172 return &map->data;
4173}
4174
4175/**
4176 * ftrace_func_mapper_add_ip - Map some data to an ip
4177 * @mapper: The mapper that has the ip maps
4178 * @ip: The instruction pointer address to map @data to
4179 * @data: The data to map to @ip
4180 *
4181 * Returns 0 on succes otherwise an error.
4182 */
4183int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4184 unsigned long ip, void *data)
4185{
4186 struct ftrace_func_entry *entry;
4187 struct ftrace_func_map *map;
4188
4189 entry = ftrace_lookup_ip(&mapper->hash, ip);
4190 if (entry)
4191 return -EBUSY;
4192
4193 map = kmalloc(sizeof(*map), GFP_KERNEL);
4194 if (!map)
4195 return -ENOMEM;
4196
4197 map->entry.ip = ip;
4198 map->data = data;
4199
4200 __add_hash_entry(&mapper->hash, &map->entry);
4201
4202 return 0;
4203}
4204
4205/**
4206 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4207 * @mapper: The mapper that has the ip maps
4208 * @ip: The instruction pointer address to remove the data from
4209 *
4210 * Returns the data if it is found, otherwise NULL.
4211 * Note, if the data pointer is used as the data itself, (see
4212 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4213 * if the data pointer was set to zero.
4214 */
4215void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4216 unsigned long ip)
4217{
4218 struct ftrace_func_entry *entry;
4219 struct ftrace_func_map *map;
4220 void *data;
4221
4222 entry = ftrace_lookup_ip(&mapper->hash, ip);
4223 if (!entry)
4224 return NULL;
4225
4226 map = (struct ftrace_func_map *)entry;
4227 data = map->data;
4228
4229 remove_hash_entry(&mapper->hash, entry);
4230 kfree(entry);
4231
4232 return data;
4233}
4234
4235/**
4236 * free_ftrace_func_mapper - free a mapping of ips and data
4237 * @mapper: The mapper that has the ip maps
4238 * @free_func: A function to be called on each data item.
4239 *
4240 * This is used to free the function mapper. The @free_func is optional
4241 * and can be used if the data needs to be freed as well.
4242 */
4243void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4244 ftrace_mapper_func free_func)
4245{
4246 struct ftrace_func_entry *entry;
4247 struct ftrace_func_map *map;
4248 struct hlist_head *hhd;
4249 int size = 1 << mapper->hash.size_bits;
4250 int i;
4251
4252 if (free_func && mapper->hash.count) {
4253 for (i = 0; i < size; i++) {
4254 hhd = &mapper->hash.buckets[i];
4255 hlist_for_each_entry(entry, hhd, hlist) {
4256 map = (struct ftrace_func_map *)entry;
4257 free_func(map);
4258 }
4259 }
4260 }
4261 free_ftrace_hash(&mapper->hash);
4262}
4263
4264static void release_probe(struct ftrace_func_probe *probe)
4265{
4266 struct ftrace_probe_ops *probe_ops;
4267
4268 mutex_lock(&ftrace_lock);
4269
4270 WARN_ON(probe->ref <= 0);
4271
4272 /* Subtract the ref that was used to protect this instance */
4273 probe->ref--;
4274
4275 if (!probe->ref) {
4276 probe_ops = probe->probe_ops;
4277 /*
4278 * Sending zero as ip tells probe_ops to free
4279 * the probe->data itself
4280 */
4281 if (probe_ops->free)
4282 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4283 list_del(&probe->list);
4284 kfree(probe);
4285 }
4286 mutex_unlock(&ftrace_lock);
4287}
4288
4289static void acquire_probe_locked(struct ftrace_func_probe *probe)
4290{
4291 /*
4292 * Add one ref to keep it from being freed when releasing the
4293 * ftrace_lock mutex.
4294 */
4295 probe->ref++;
4296}
4297
4298int
4299register_ftrace_function_probe(char *glob, struct trace_array *tr,
4300 struct ftrace_probe_ops *probe_ops,
4301 void *data)
4302{
4303 struct ftrace_func_entry *entry;
4304 struct ftrace_func_probe *probe;
4305 struct ftrace_hash **orig_hash;
4306 struct ftrace_hash *old_hash;
4307 struct ftrace_hash *hash;
4308 int count = 0;
4309 int size;
4310 int ret;
4311 int i;
4312
4313 if (WARN_ON(!tr))
4314 return -EINVAL;
4315
4316 /* We do not support '!' for function probes */
4317 if (WARN_ON(glob[0] == '!'))
4318 return -EINVAL;
4319
4320
4321 mutex_lock(&ftrace_lock);
4322 /* Check if the probe_ops is already registered */
4323 list_for_each_entry(probe, &tr->func_probes, list) {
4324 if (probe->probe_ops == probe_ops)
4325 break;
4326 }
4327 if (&probe->list == &tr->func_probes) {
4328 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4329 if (!probe) {
4330 mutex_unlock(&ftrace_lock);
4331 return -ENOMEM;
4332 }
4333 probe->probe_ops = probe_ops;
4334 probe->ops.func = function_trace_probe_call;
4335 probe->tr = tr;
4336 ftrace_ops_init(&probe->ops);
4337 list_add(&probe->list, &tr->func_probes);
4338 }
4339
4340 acquire_probe_locked(probe);
4341
4342 mutex_unlock(&ftrace_lock);
4343
4344 mutex_lock(&probe->ops.func_hash->regex_lock);
4345
4346 orig_hash = &probe->ops.func_hash->filter_hash;
4347 old_hash = *orig_hash;
4348 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4349
4350 ret = ftrace_match_records(hash, glob, strlen(glob));
4351
4352 /* Nothing found? */
4353 if (!ret)
4354 ret = -EINVAL;
4355
4356 if (ret < 0)
4357 goto out;
4358
4359 size = 1 << hash->size_bits;
4360 for (i = 0; i < size; i++) {
4361 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4362 if (ftrace_lookup_ip(old_hash, entry->ip))
4363 continue;
4364 /*
4365 * The caller might want to do something special
4366 * for each function we find. We call the callback
4367 * to give the caller an opportunity to do so.
4368 */
4369 if (probe_ops->init) {
4370 ret = probe_ops->init(probe_ops, tr,
4371 entry->ip, data,
4372 &probe->data);
4373 if (ret < 0) {
4374 if (probe_ops->free && count)
4375 probe_ops->free(probe_ops, tr,
4376 0, probe->data);
4377 probe->data = NULL;
4378 goto out;
4379 }
4380 }
4381 count++;
4382 }
4383 }
4384
4385 mutex_lock(&ftrace_lock);
4386
4387 if (!count) {
4388 /* Nothing was added? */
4389 ret = -EINVAL;
4390 goto out_unlock;
4391 }
4392
4393 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4394 hash, 1);
4395 if (ret < 0)
4396 goto err_unlock;
4397
4398 /* One ref for each new function traced */
4399 probe->ref += count;
4400
4401 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4402 ret = ftrace_startup(&probe->ops, 0);
4403
4404 out_unlock:
4405 mutex_unlock(&ftrace_lock);
4406
4407 if (!ret)
4408 ret = count;
4409 out:
4410 mutex_unlock(&probe->ops.func_hash->regex_lock);
4411 free_ftrace_hash(hash);
4412
4413 release_probe(probe);
4414
4415 return ret;
4416
4417 err_unlock:
4418 if (!probe_ops->free || !count)
4419 goto out_unlock;
4420
4421 /* Failed to do the move, need to call the free functions */
4422 for (i = 0; i < size; i++) {
4423 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4424 if (ftrace_lookup_ip(old_hash, entry->ip))
4425 continue;
4426 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4427 }
4428 }
4429 goto out_unlock;
4430}
4431
4432int
4433unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4434 struct ftrace_probe_ops *probe_ops)
4435{
4436 struct ftrace_ops_hash old_hash_ops;
4437 struct ftrace_func_entry *entry;
4438 struct ftrace_func_probe *probe;
4439 struct ftrace_glob func_g;
4440 struct ftrace_hash **orig_hash;
4441 struct ftrace_hash *old_hash;
4442 struct ftrace_hash *hash = NULL;
4443 struct hlist_node *tmp;
4444 struct hlist_head hhd;
4445 char str[KSYM_SYMBOL_LEN];
4446 int count = 0;
4447 int i, ret = -ENODEV;
4448 int size;
4449
4450 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4451 func_g.search = NULL;
4452 else {
4453 int not;
4454
4455 func_g.type = filter_parse_regex(glob, strlen(glob),
4456 &func_g.search, ¬);
4457 func_g.len = strlen(func_g.search);
4458
4459 /* we do not support '!' for function probes */
4460 if (WARN_ON(not))
4461 return -EINVAL;
4462 }
4463
4464 mutex_lock(&ftrace_lock);
4465 /* Check if the probe_ops is already registered */
4466 list_for_each_entry(probe, &tr->func_probes, list) {
4467 if (probe->probe_ops == probe_ops)
4468 break;
4469 }
4470 if (&probe->list == &tr->func_probes)
4471 goto err_unlock_ftrace;
4472
4473 ret = -EINVAL;
4474 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4475 goto err_unlock_ftrace;
4476
4477 acquire_probe_locked(probe);
4478
4479 mutex_unlock(&ftrace_lock);
4480
4481 mutex_lock(&probe->ops.func_hash->regex_lock);
4482
4483 orig_hash = &probe->ops.func_hash->filter_hash;
4484 old_hash = *orig_hash;
4485
4486 if (ftrace_hash_empty(old_hash))
4487 goto out_unlock;
4488
4489 old_hash_ops.filter_hash = old_hash;
4490 /* Probes only have filters */
4491 old_hash_ops.notrace_hash = NULL;
4492
4493 ret = -ENOMEM;
4494 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4495 if (!hash)
4496 goto out_unlock;
4497
4498 INIT_HLIST_HEAD(&hhd);
4499
4500 size = 1 << hash->size_bits;
4501 for (i = 0; i < size; i++) {
4502 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4503
4504 if (func_g.search) {
4505 kallsyms_lookup(entry->ip, NULL, NULL,
4506 NULL, str);
4507 if (!ftrace_match(str, &func_g))
4508 continue;
4509 }
4510 count++;
4511 remove_hash_entry(hash, entry);
4512 hlist_add_head(&entry->hlist, &hhd);
4513 }
4514 }
4515
4516 /* Nothing found? */
4517 if (!count) {
4518 ret = -EINVAL;
4519 goto out_unlock;
4520 }
4521
4522 mutex_lock(&ftrace_lock);
4523
4524 WARN_ON(probe->ref < count);
4525
4526 probe->ref -= count;
4527
4528 if (ftrace_hash_empty(hash))
4529 ftrace_shutdown(&probe->ops, 0);
4530
4531 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4532 hash, 1);
4533
4534 /* still need to update the function call sites */
4535 if (ftrace_enabled && !ftrace_hash_empty(hash))
4536 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4537 &old_hash_ops);
4538 synchronize_sched();
4539
4540 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4541 hlist_del(&entry->hlist);
4542 if (probe_ops->free)
4543 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4544 kfree(entry);
4545 }
4546 mutex_unlock(&ftrace_lock);
4547
4548 out_unlock:
4549 mutex_unlock(&probe->ops.func_hash->regex_lock);
4550 free_ftrace_hash(hash);
4551
4552 release_probe(probe);
4553
4554 return ret;
4555
4556 err_unlock_ftrace:
4557 mutex_unlock(&ftrace_lock);
4558 return ret;
4559}
4560
4561void clear_ftrace_function_probes(struct trace_array *tr)
4562{
4563 struct ftrace_func_probe *probe, *n;
4564
4565 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4566 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4567}
4568
4569static LIST_HEAD(ftrace_commands);
4570static DEFINE_MUTEX(ftrace_cmd_mutex);
4571
4572/*
4573 * Currently we only register ftrace commands from __init, so mark this
4574 * __init too.
4575 */
4576__init int register_ftrace_command(struct ftrace_func_command *cmd)
4577{
4578 struct ftrace_func_command *p;
4579 int ret = 0;
4580
4581 mutex_lock(&ftrace_cmd_mutex);
4582 list_for_each_entry(p, &ftrace_commands, list) {
4583 if (strcmp(cmd->name, p->name) == 0) {
4584 ret = -EBUSY;
4585 goto out_unlock;
4586 }
4587 }
4588 list_add(&cmd->list, &ftrace_commands);
4589 out_unlock:
4590 mutex_unlock(&ftrace_cmd_mutex);
4591
4592 return ret;
4593}
4594
4595/*
4596 * Currently we only unregister ftrace commands from __init, so mark
4597 * this __init too.
4598 */
4599__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4600{
4601 struct ftrace_func_command *p, *n;
4602 int ret = -ENODEV;
4603
4604 mutex_lock(&ftrace_cmd_mutex);
4605 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4606 if (strcmp(cmd->name, p->name) == 0) {
4607 ret = 0;
4608 list_del_init(&p->list);
4609 goto out_unlock;
4610 }
4611 }
4612 out_unlock:
4613 mutex_unlock(&ftrace_cmd_mutex);
4614
4615 return ret;
4616}
4617
4618static int ftrace_process_regex(struct ftrace_iterator *iter,
4619 char *buff, int len, int enable)
4620{
4621 struct ftrace_hash *hash = iter->hash;
4622 struct trace_array *tr = iter->ops->private;
4623 char *func, *command, *next = buff;
4624 struct ftrace_func_command *p;
4625 int ret = -EINVAL;
4626
4627 func = strsep(&next, ":");
4628
4629 if (!next) {
4630 ret = ftrace_match_records(hash, func, len);
4631 if (!ret)
4632 ret = -EINVAL;
4633 if (ret < 0)
4634 return ret;
4635 return 0;
4636 }
4637
4638 /* command found */
4639
4640 command = strsep(&next, ":");
4641
4642 mutex_lock(&ftrace_cmd_mutex);
4643 list_for_each_entry(p, &ftrace_commands, list) {
4644 if (strcmp(p->name, command) == 0) {
4645 ret = p->func(tr, hash, func, command, next, enable);
4646 goto out_unlock;
4647 }
4648 }
4649 out_unlock:
4650 mutex_unlock(&ftrace_cmd_mutex);
4651
4652 return ret;
4653}
4654
4655static ssize_t
4656ftrace_regex_write(struct file *file, const char __user *ubuf,
4657 size_t cnt, loff_t *ppos, int enable)
4658{
4659 struct ftrace_iterator *iter;
4660 struct trace_parser *parser;
4661 ssize_t ret, read;
4662
4663 if (!cnt)
4664 return 0;
4665
4666 if (file->f_mode & FMODE_READ) {
4667 struct seq_file *m = file->private_data;
4668 iter = m->private;
4669 } else
4670 iter = file->private_data;
4671
4672 if (unlikely(ftrace_disabled))
4673 return -ENODEV;
4674
4675 /* iter->hash is a local copy, so we don't need regex_lock */
4676
4677 parser = &iter->parser;
4678 read = trace_get_user(parser, ubuf, cnt, ppos);
4679
4680 if (read >= 0 && trace_parser_loaded(parser) &&
4681 !trace_parser_cont(parser)) {
4682 ret = ftrace_process_regex(iter, parser->buffer,
4683 parser->idx, enable);
4684 trace_parser_clear(parser);
4685 if (ret < 0)
4686 goto out;
4687 }
4688
4689 ret = read;
4690 out:
4691 return ret;
4692}
4693
4694ssize_t
4695ftrace_filter_write(struct file *file, const char __user *ubuf,
4696 size_t cnt, loff_t *ppos)
4697{
4698 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4699}
4700
4701ssize_t
4702ftrace_notrace_write(struct file *file, const char __user *ubuf,
4703 size_t cnt, loff_t *ppos)
4704{
4705 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4706}
4707
4708static int
4709ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4710{
4711 struct ftrace_func_entry *entry;
4712
4713 if (!ftrace_location(ip))
4714 return -EINVAL;
4715
4716 if (remove) {
4717 entry = ftrace_lookup_ip(hash, ip);
4718 if (!entry)
4719 return -ENOENT;
4720 free_hash_entry(hash, entry);
4721 return 0;
4722 }
4723
4724 return add_hash_entry(hash, ip);
4725}
4726
4727static int
4728ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4729 unsigned long ip, int remove, int reset, int enable)
4730{
4731 struct ftrace_hash **orig_hash;
4732 struct ftrace_hash *hash;
4733 int ret;
4734
4735 if (unlikely(ftrace_disabled))
4736 return -ENODEV;
4737
4738 mutex_lock(&ops->func_hash->regex_lock);
4739
4740 if (enable)
4741 orig_hash = &ops->func_hash->filter_hash;
4742 else
4743 orig_hash = &ops->func_hash->notrace_hash;
4744
4745 if (reset)
4746 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4747 else
4748 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4749
4750 if (!hash) {
4751 ret = -ENOMEM;
4752 goto out_regex_unlock;
4753 }
4754
4755 if (buf && !ftrace_match_records(hash, buf, len)) {
4756 ret = -EINVAL;
4757 goto out_regex_unlock;
4758 }
4759 if (ip) {
4760 ret = ftrace_match_addr(hash, ip, remove);
4761 if (ret < 0)
4762 goto out_regex_unlock;
4763 }
4764
4765 mutex_lock(&ftrace_lock);
4766 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4767 mutex_unlock(&ftrace_lock);
4768
4769 out_regex_unlock:
4770 mutex_unlock(&ops->func_hash->regex_lock);
4771
4772 free_ftrace_hash(hash);
4773 return ret;
4774}
4775
4776static int
4777ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4778 int reset, int enable)
4779{
4780 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4781}
4782
4783/**
4784 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4785 * @ops - the ops to set the filter with
4786 * @ip - the address to add to or remove from the filter.
4787 * @remove - non zero to remove the ip from the filter
4788 * @reset - non zero to reset all filters before applying this filter.
4789 *
4790 * Filters denote which functions should be enabled when tracing is enabled
4791 * If @ip is NULL, it failes to update filter.
4792 */
4793int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4794 int remove, int reset)
4795{
4796 ftrace_ops_init(ops);
4797 return ftrace_set_addr(ops, ip, remove, reset, 1);
4798}
4799EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4800
4801/**
4802 * ftrace_ops_set_global_filter - setup ops to use global filters
4803 * @ops - the ops which will use the global filters
4804 *
4805 * ftrace users who need global function trace filtering should call this.
4806 * It can set the global filter only if ops were not initialized before.
4807 */
4808void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4809{
4810 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4811 return;
4812
4813 ftrace_ops_init(ops);
4814 ops->func_hash = &global_ops.local_hash;
4815}
4816EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4817
4818static int
4819ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4820 int reset, int enable)
4821{
4822 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4823}
4824
4825/**
4826 * ftrace_set_filter - set a function to filter on in ftrace
4827 * @ops - the ops to set the filter with
4828 * @buf - the string that holds the function filter text.
4829 * @len - the length of the string.
4830 * @reset - non zero to reset all filters before applying this filter.
4831 *
4832 * Filters denote which functions should be enabled when tracing is enabled.
4833 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4834 */
4835int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4836 int len, int reset)
4837{
4838 ftrace_ops_init(ops);
4839 return ftrace_set_regex(ops, buf, len, reset, 1);
4840}
4841EXPORT_SYMBOL_GPL(ftrace_set_filter);
4842
4843/**
4844 * ftrace_set_notrace - set a function to not trace in ftrace
4845 * @ops - the ops to set the notrace filter with
4846 * @buf - the string that holds the function notrace text.
4847 * @len - the length of the string.
4848 * @reset - non zero to reset all filters before applying this filter.
4849 *
4850 * Notrace Filters denote which functions should not be enabled when tracing
4851 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4852 * for tracing.
4853 */
4854int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4855 int len, int reset)
4856{
4857 ftrace_ops_init(ops);
4858 return ftrace_set_regex(ops, buf, len, reset, 0);
4859}
4860EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4861/**
4862 * ftrace_set_global_filter - set a function to filter on with global tracers
4863 * @buf - the string that holds the function filter text.
4864 * @len - the length of the string.
4865 * @reset - non zero to reset all filters before applying this filter.
4866 *
4867 * Filters denote which functions should be enabled when tracing is enabled.
4868 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4869 */
4870void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4871{
4872 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4873}
4874EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4875
4876/**
4877 * ftrace_set_global_notrace - set a function to not trace with global tracers
4878 * @buf - the string that holds the function notrace text.
4879 * @len - the length of the string.
4880 * @reset - non zero to reset all filters before applying this filter.
4881 *
4882 * Notrace Filters denote which functions should not be enabled when tracing
4883 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4884 * for tracing.
4885 */
4886void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4887{
4888 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4889}
4890EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4891
4892/*
4893 * command line interface to allow users to set filters on boot up.
4894 */
4895#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4896static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4897static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4898
4899/* Used by function selftest to not test if filter is set */
4900bool ftrace_filter_param __initdata;
4901
4902static int __init set_ftrace_notrace(char *str)
4903{
4904 ftrace_filter_param = true;
4905 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4906 return 1;
4907}
4908__setup("ftrace_notrace=", set_ftrace_notrace);
4909
4910static int __init set_ftrace_filter(char *str)
4911{
4912 ftrace_filter_param = true;
4913 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4914 return 1;
4915}
4916__setup("ftrace_filter=", set_ftrace_filter);
4917
4918#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4919static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4920static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4921static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4922
4923static int __init set_graph_function(char *str)
4924{
4925 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4926 return 1;
4927}
4928__setup("ftrace_graph_filter=", set_graph_function);
4929
4930static int __init set_graph_notrace_function(char *str)
4931{
4932 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4933 return 1;
4934}
4935__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4936
4937static int __init set_graph_max_depth_function(char *str)
4938{
4939 if (!str)
4940 return 0;
4941 fgraph_max_depth = simple_strtoul(str, NULL, 0);
4942 return 1;
4943}
4944__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4945
4946static void __init set_ftrace_early_graph(char *buf, int enable)
4947{
4948 int ret;
4949 char *func;
4950 struct ftrace_hash *hash;
4951
4952 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4953 if (WARN_ON(!hash))
4954 return;
4955
4956 while (buf) {
4957 func = strsep(&buf, ",");
4958 /* we allow only one expression at a time */
4959 ret = ftrace_graph_set_hash(hash, func);
4960 if (ret)
4961 printk(KERN_DEBUG "ftrace: function %s not "
4962 "traceable\n", func);
4963 }
4964
4965 if (enable)
4966 ftrace_graph_hash = hash;
4967 else
4968 ftrace_graph_notrace_hash = hash;
4969}
4970#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4971
4972void __init
4973ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4974{
4975 char *func;
4976
4977 ftrace_ops_init(ops);
4978
4979 while (buf) {
4980 func = strsep(&buf, ",");
4981 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4982 }
4983}
4984
4985static void __init set_ftrace_early_filters(void)
4986{
4987 if (ftrace_filter_buf[0])
4988 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4989 if (ftrace_notrace_buf[0])
4990 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4991#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4992 if (ftrace_graph_buf[0])
4993 set_ftrace_early_graph(ftrace_graph_buf, 1);
4994 if (ftrace_graph_notrace_buf[0])
4995 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4996#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4997}
4998
4999int ftrace_regex_release(struct inode *inode, struct file *file)
5000{
5001 struct seq_file *m = (struct seq_file *)file->private_data;
5002 struct ftrace_iterator *iter;
5003 struct ftrace_hash **orig_hash;
5004 struct trace_parser *parser;
5005 int filter_hash;
5006 int ret;
5007
5008 if (file->f_mode & FMODE_READ) {
5009 iter = m->private;
5010 seq_release(inode, file);
5011 } else
5012 iter = file->private_data;
5013
5014 parser = &iter->parser;
5015 if (trace_parser_loaded(parser)) {
5016 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5017 }
5018
5019 trace_parser_put(parser);
5020
5021 mutex_lock(&iter->ops->func_hash->regex_lock);
5022
5023 if (file->f_mode & FMODE_WRITE) {
5024 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5025
5026 if (filter_hash) {
5027 orig_hash = &iter->ops->func_hash->filter_hash;
5028 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5029 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5030 } else
5031 orig_hash = &iter->ops->func_hash->notrace_hash;
5032
5033 mutex_lock(&ftrace_lock);
5034 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5035 iter->hash, filter_hash);
5036 mutex_unlock(&ftrace_lock);
5037 } else {
5038 /* For read only, the hash is the ops hash */
5039 iter->hash = NULL;
5040 }
5041
5042 mutex_unlock(&iter->ops->func_hash->regex_lock);
5043 free_ftrace_hash(iter->hash);
5044 kfree(iter);
5045
5046 return 0;
5047}
5048
5049static const struct file_operations ftrace_avail_fops = {
5050 .open = ftrace_avail_open,
5051 .read = seq_read,
5052 .llseek = seq_lseek,
5053 .release = seq_release_private,
5054};
5055
5056static const struct file_operations ftrace_enabled_fops = {
5057 .open = ftrace_enabled_open,
5058 .read = seq_read,
5059 .llseek = seq_lseek,
5060 .release = seq_release_private,
5061};
5062
5063static const struct file_operations ftrace_filter_fops = {
5064 .open = ftrace_filter_open,
5065 .read = seq_read,
5066 .write = ftrace_filter_write,
5067 .llseek = tracing_lseek,
5068 .release = ftrace_regex_release,
5069};
5070
5071static const struct file_operations ftrace_notrace_fops = {
5072 .open = ftrace_notrace_open,
5073 .read = seq_read,
5074 .write = ftrace_notrace_write,
5075 .llseek = tracing_lseek,
5076 .release = ftrace_regex_release,
5077};
5078
5079#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5080
5081static DEFINE_MUTEX(graph_lock);
5082
5083struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
5084struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
5085
5086enum graph_filter_type {
5087 GRAPH_FILTER_NOTRACE = 0,
5088 GRAPH_FILTER_FUNCTION,
5089};
5090
5091#define FTRACE_GRAPH_EMPTY ((void *)1)
5092
5093struct ftrace_graph_data {
5094 struct ftrace_hash *hash;
5095 struct ftrace_func_entry *entry;
5096 int idx; /* for hash table iteration */
5097 enum graph_filter_type type;
5098 struct ftrace_hash *new_hash;
5099 const struct seq_operations *seq_ops;
5100 struct trace_parser parser;
5101};
5102
5103static void *
5104__g_next(struct seq_file *m, loff_t *pos)
5105{
5106 struct ftrace_graph_data *fgd = m->private;
5107 struct ftrace_func_entry *entry = fgd->entry;
5108 struct hlist_head *head;
5109 int i, idx = fgd->idx;
5110
5111 if (*pos >= fgd->hash->count)
5112 return NULL;
5113
5114 if (entry) {
5115 hlist_for_each_entry_continue(entry, hlist) {
5116 fgd->entry = entry;
5117 return entry;
5118 }
5119
5120 idx++;
5121 }
5122
5123 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5124 head = &fgd->hash->buckets[i];
5125 hlist_for_each_entry(entry, head, hlist) {
5126 fgd->entry = entry;
5127 fgd->idx = i;
5128 return entry;
5129 }
5130 }
5131 return NULL;
5132}
5133
5134static void *
5135g_next(struct seq_file *m, void *v, loff_t *pos)
5136{
5137 (*pos)++;
5138 return __g_next(m, pos);
5139}
5140
5141static void *g_start(struct seq_file *m, loff_t *pos)
5142{
5143 struct ftrace_graph_data *fgd = m->private;
5144
5145 mutex_lock(&graph_lock);
5146
5147 if (fgd->type == GRAPH_FILTER_FUNCTION)
5148 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5149 lockdep_is_held(&graph_lock));
5150 else
5151 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5152 lockdep_is_held(&graph_lock));
5153
5154 /* Nothing, tell g_show to print all functions are enabled */
5155 if (ftrace_hash_empty(fgd->hash) && !*pos)
5156 return FTRACE_GRAPH_EMPTY;
5157
5158 fgd->idx = 0;
5159 fgd->entry = NULL;
5160 return __g_next(m, pos);
5161}
5162
5163static void g_stop(struct seq_file *m, void *p)
5164{
5165 mutex_unlock(&graph_lock);
5166}
5167
5168static int g_show(struct seq_file *m, void *v)
5169{
5170 struct ftrace_func_entry *entry = v;
5171
5172 if (!entry)
5173 return 0;
5174
5175 if (entry == FTRACE_GRAPH_EMPTY) {
5176 struct ftrace_graph_data *fgd = m->private;
5177
5178 if (fgd->type == GRAPH_FILTER_FUNCTION)
5179 seq_puts(m, "#### all functions enabled ####\n");
5180 else
5181 seq_puts(m, "#### no functions disabled ####\n");
5182 return 0;
5183 }
5184
5185 seq_printf(m, "%ps\n", (void *)entry->ip);
5186
5187 return 0;
5188}
5189
5190static const struct seq_operations ftrace_graph_seq_ops = {
5191 .start = g_start,
5192 .next = g_next,
5193 .stop = g_stop,
5194 .show = g_show,
5195};
5196
5197static int
5198__ftrace_graph_open(struct inode *inode, struct file *file,
5199 struct ftrace_graph_data *fgd)
5200{
5201 int ret = 0;
5202 struct ftrace_hash *new_hash = NULL;
5203
5204 if (file->f_mode & FMODE_WRITE) {
5205 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5206
5207 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5208 return -ENOMEM;
5209
5210 if (file->f_flags & O_TRUNC)
5211 new_hash = alloc_ftrace_hash(size_bits);
5212 else
5213 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5214 fgd->hash);
5215 if (!new_hash) {
5216 ret = -ENOMEM;
5217 goto out;
5218 }
5219 }
5220
5221 if (file->f_mode & FMODE_READ) {
5222 ret = seq_open(file, &ftrace_graph_seq_ops);
5223 if (!ret) {
5224 struct seq_file *m = file->private_data;
5225 m->private = fgd;
5226 } else {
5227 /* Failed */
5228 free_ftrace_hash(new_hash);
5229 new_hash = NULL;
5230 }
5231 } else
5232 file->private_data = fgd;
5233
5234out:
5235 if (ret < 0 && file->f_mode & FMODE_WRITE)
5236 trace_parser_put(&fgd->parser);
5237
5238 fgd->new_hash = new_hash;
5239
5240 /*
5241 * All uses of fgd->hash must be taken with the graph_lock
5242 * held. The graph_lock is going to be released, so force
5243 * fgd->hash to be reinitialized when it is taken again.
5244 */
5245 fgd->hash = NULL;
5246
5247 return ret;
5248}
5249
5250static int
5251ftrace_graph_open(struct inode *inode, struct file *file)
5252{
5253 struct ftrace_graph_data *fgd;
5254 int ret;
5255
5256 if (unlikely(ftrace_disabled))
5257 return -ENODEV;
5258
5259 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5260 if (fgd == NULL)
5261 return -ENOMEM;
5262
5263 mutex_lock(&graph_lock);
5264
5265 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5266 lockdep_is_held(&graph_lock));
5267 fgd->type = GRAPH_FILTER_FUNCTION;
5268 fgd->seq_ops = &ftrace_graph_seq_ops;
5269
5270 ret = __ftrace_graph_open(inode, file, fgd);
5271 if (ret < 0)
5272 kfree(fgd);
5273
5274 mutex_unlock(&graph_lock);
5275 return ret;
5276}
5277
5278static int
5279ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5280{
5281 struct ftrace_graph_data *fgd;
5282 int ret;
5283
5284 if (unlikely(ftrace_disabled))
5285 return -ENODEV;
5286
5287 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5288 if (fgd == NULL)
5289 return -ENOMEM;
5290
5291 mutex_lock(&graph_lock);
5292
5293 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5294 lockdep_is_held(&graph_lock));
5295 fgd->type = GRAPH_FILTER_NOTRACE;
5296 fgd->seq_ops = &ftrace_graph_seq_ops;
5297
5298 ret = __ftrace_graph_open(inode, file, fgd);
5299 if (ret < 0)
5300 kfree(fgd);
5301
5302 mutex_unlock(&graph_lock);
5303 return ret;
5304}
5305
5306static int
5307ftrace_graph_release(struct inode *inode, struct file *file)
5308{
5309 struct ftrace_graph_data *fgd;
5310 struct ftrace_hash *old_hash, *new_hash;
5311 struct trace_parser *parser;
5312 int ret = 0;
5313
5314 if (file->f_mode & FMODE_READ) {
5315 struct seq_file *m = file->private_data;
5316
5317 fgd = m->private;
5318 seq_release(inode, file);
5319 } else {
5320 fgd = file->private_data;
5321 }
5322
5323
5324 if (file->f_mode & FMODE_WRITE) {
5325
5326 parser = &fgd->parser;
5327
5328 if (trace_parser_loaded((parser))) {
5329 ret = ftrace_graph_set_hash(fgd->new_hash,
5330 parser->buffer);
5331 }
5332
5333 trace_parser_put(parser);
5334
5335 new_hash = __ftrace_hash_move(fgd->new_hash);
5336 if (!new_hash) {
5337 ret = -ENOMEM;
5338 goto out;
5339 }
5340
5341 mutex_lock(&graph_lock);
5342
5343 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5344 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5345 lockdep_is_held(&graph_lock));
5346 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5347 } else {
5348 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5349 lockdep_is_held(&graph_lock));
5350 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5351 }
5352
5353 mutex_unlock(&graph_lock);
5354
5355 /* Wait till all users are no longer using the old hash */
5356 synchronize_sched();
5357
5358 free_ftrace_hash(old_hash);
5359 }
5360
5361 out:
5362 free_ftrace_hash(fgd->new_hash);
5363 kfree(fgd);
5364
5365 return ret;
5366}
5367
5368static int
5369ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5370{
5371 struct ftrace_glob func_g;
5372 struct dyn_ftrace *rec;
5373 struct ftrace_page *pg;
5374 struct ftrace_func_entry *entry;
5375 int fail = 1;
5376 int not;
5377
5378 /* decode regex */
5379 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5380 &func_g.search, ¬);
5381
5382 func_g.len = strlen(func_g.search);
5383
5384 mutex_lock(&ftrace_lock);
5385
5386 if (unlikely(ftrace_disabled)) {
5387 mutex_unlock(&ftrace_lock);
5388 return -ENODEV;
5389 }
5390
5391 do_for_each_ftrace_rec(pg, rec) {
5392
5393 if (rec->flags & FTRACE_FL_DISABLED)
5394 continue;
5395
5396 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5397 entry = ftrace_lookup_ip(hash, rec->ip);
5398
5399 if (!not) {
5400 fail = 0;
5401
5402 if (entry)
5403 continue;
5404 if (add_hash_entry(hash, rec->ip) < 0)
5405 goto out;
5406 } else {
5407 if (entry) {
5408 free_hash_entry(hash, entry);
5409 fail = 0;
5410 }
5411 }
5412 }
5413 } while_for_each_ftrace_rec();
5414out:
5415 mutex_unlock(&ftrace_lock);
5416
5417 if (fail)
5418 return -EINVAL;
5419
5420 return 0;
5421}
5422
5423static ssize_t
5424ftrace_graph_write(struct file *file, const char __user *ubuf,
5425 size_t cnt, loff_t *ppos)
5426{
5427 ssize_t read, ret = 0;
5428 struct ftrace_graph_data *fgd = file->private_data;
5429 struct trace_parser *parser;
5430
5431 if (!cnt)
5432 return 0;
5433
5434 /* Read mode uses seq functions */
5435 if (file->f_mode & FMODE_READ) {
5436 struct seq_file *m = file->private_data;
5437 fgd = m->private;
5438 }
5439
5440 parser = &fgd->parser;
5441
5442 read = trace_get_user(parser, ubuf, cnt, ppos);
5443
5444 if (read >= 0 && trace_parser_loaded(parser) &&
5445 !trace_parser_cont(parser)) {
5446
5447 ret = ftrace_graph_set_hash(fgd->new_hash,
5448 parser->buffer);
5449 trace_parser_clear(parser);
5450 }
5451
5452 if (!ret)
5453 ret = read;
5454
5455 return ret;
5456}
5457
5458static const struct file_operations ftrace_graph_fops = {
5459 .open = ftrace_graph_open,
5460 .read = seq_read,
5461 .write = ftrace_graph_write,
5462 .llseek = tracing_lseek,
5463 .release = ftrace_graph_release,
5464};
5465
5466static const struct file_operations ftrace_graph_notrace_fops = {
5467 .open = ftrace_graph_notrace_open,
5468 .read = seq_read,
5469 .write = ftrace_graph_write,
5470 .llseek = tracing_lseek,
5471 .release = ftrace_graph_release,
5472};
5473#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5474
5475void ftrace_create_filter_files(struct ftrace_ops *ops,
5476 struct dentry *parent)
5477{
5478
5479 trace_create_file("set_ftrace_filter", 0644, parent,
5480 ops, &ftrace_filter_fops);
5481
5482 trace_create_file("set_ftrace_notrace", 0644, parent,
5483 ops, &ftrace_notrace_fops);
5484}
5485
5486/*
5487 * The name "destroy_filter_files" is really a misnomer. Although
5488 * in the future, it may actualy delete the files, but this is
5489 * really intended to make sure the ops passed in are disabled
5490 * and that when this function returns, the caller is free to
5491 * free the ops.
5492 *
5493 * The "destroy" name is only to match the "create" name that this
5494 * should be paired with.
5495 */
5496void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5497{
5498 mutex_lock(&ftrace_lock);
5499 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5500 ftrace_shutdown(ops, 0);
5501 ops->flags |= FTRACE_OPS_FL_DELETED;
5502 mutex_unlock(&ftrace_lock);
5503}
5504
5505static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5506{
5507
5508 trace_create_file("available_filter_functions", 0444,
5509 d_tracer, NULL, &ftrace_avail_fops);
5510
5511 trace_create_file("enabled_functions", 0444,
5512 d_tracer, NULL, &ftrace_enabled_fops);
5513
5514 ftrace_create_filter_files(&global_ops, d_tracer);
5515
5516#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5517 trace_create_file("set_graph_function", 0644, d_tracer,
5518 NULL,
5519 &ftrace_graph_fops);
5520 trace_create_file("set_graph_notrace", 0644, d_tracer,
5521 NULL,
5522 &ftrace_graph_notrace_fops);
5523#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5524
5525 return 0;
5526}
5527
5528static int ftrace_cmp_ips(const void *a, const void *b)
5529{
5530 const unsigned long *ipa = a;
5531 const unsigned long *ipb = b;
5532
5533 if (*ipa > *ipb)
5534 return 1;
5535 if (*ipa < *ipb)
5536 return -1;
5537 return 0;
5538}
5539
5540static int ftrace_process_locs(struct module *mod,
5541 unsigned long *start,
5542 unsigned long *end)
5543{
5544 struct ftrace_page *start_pg;
5545 struct ftrace_page *pg;
5546 struct dyn_ftrace *rec;
5547 unsigned long count;
5548 unsigned long *p;
5549 unsigned long addr;
5550 unsigned long flags = 0; /* Shut up gcc */
5551 int ret = -ENOMEM;
5552
5553 count = end - start;
5554
5555 if (!count)
5556 return 0;
5557
5558 sort(start, count, sizeof(*start),
5559 ftrace_cmp_ips, NULL);
5560
5561 start_pg = ftrace_allocate_pages(count);
5562 if (!start_pg)
5563 return -ENOMEM;
5564
5565 mutex_lock(&ftrace_lock);
5566
5567 /*
5568 * Core and each module needs their own pages, as
5569 * modules will free them when they are removed.
5570 * Force a new page to be allocated for modules.
5571 */
5572 if (!mod) {
5573 WARN_ON(ftrace_pages || ftrace_pages_start);
5574 /* First initialization */
5575 ftrace_pages = ftrace_pages_start = start_pg;
5576 } else {
5577 if (!ftrace_pages)
5578 goto out;
5579
5580 if (WARN_ON(ftrace_pages->next)) {
5581 /* Hmm, we have free pages? */
5582 while (ftrace_pages->next)
5583 ftrace_pages = ftrace_pages->next;
5584 }
5585
5586 ftrace_pages->next = start_pg;
5587 }
5588
5589 p = start;
5590 pg = start_pg;
5591 while (p < end) {
5592 addr = ftrace_call_adjust(*p++);
5593 /*
5594 * Some architecture linkers will pad between
5595 * the different mcount_loc sections of different
5596 * object files to satisfy alignments.
5597 * Skip any NULL pointers.
5598 */
5599 if (!addr)
5600 continue;
5601
5602 if (pg->index == pg->size) {
5603 /* We should have allocated enough */
5604 if (WARN_ON(!pg->next))
5605 break;
5606 pg = pg->next;
5607 }
5608
5609 rec = &pg->records[pg->index++];
5610 rec->ip = addr;
5611 }
5612
5613 /* We should have used all pages */
5614 WARN_ON(pg->next);
5615
5616 /* Assign the last page to ftrace_pages */
5617 ftrace_pages = pg;
5618
5619 /*
5620 * We only need to disable interrupts on start up
5621 * because we are modifying code that an interrupt
5622 * may execute, and the modification is not atomic.
5623 * But for modules, nothing runs the code we modify
5624 * until we are finished with it, and there's no
5625 * reason to cause large interrupt latencies while we do it.
5626 */
5627 if (!mod)
5628 local_irq_save(flags);
5629 ftrace_update_code(mod, start_pg);
5630 if (!mod)
5631 local_irq_restore(flags);
5632 ret = 0;
5633 out:
5634 mutex_unlock(&ftrace_lock);
5635
5636 return ret;
5637}
5638
5639struct ftrace_mod_func {
5640 struct list_head list;
5641 char *name;
5642 unsigned long ip;
5643 unsigned int size;
5644};
5645
5646struct ftrace_mod_map {
5647 struct rcu_head rcu;
5648 struct list_head list;
5649 struct module *mod;
5650 unsigned long start_addr;
5651 unsigned long end_addr;
5652 struct list_head funcs;
5653 unsigned int num_funcs;
5654};
5655
5656#ifdef CONFIG_MODULES
5657
5658#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5659
5660static LIST_HEAD(ftrace_mod_maps);
5661
5662static int referenced_filters(struct dyn_ftrace *rec)
5663{
5664 struct ftrace_ops *ops;
5665 int cnt = 0;
5666
5667 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5668 if (ops_references_rec(ops, rec))
5669 cnt++;
5670 }
5671
5672 return cnt;
5673}
5674
5675static void
5676clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5677{
5678 struct ftrace_func_entry *entry;
5679 struct dyn_ftrace *rec;
5680 int i;
5681
5682 if (ftrace_hash_empty(hash))
5683 return;
5684
5685 for (i = 0; i < pg->index; i++) {
5686 rec = &pg->records[i];
5687 entry = __ftrace_lookup_ip(hash, rec->ip);
5688 /*
5689 * Do not allow this rec to match again.
5690 * Yeah, it may waste some memory, but will be removed
5691 * if/when the hash is modified again.
5692 */
5693 if (entry)
5694 entry->ip = 0;
5695 }
5696}
5697
5698/* Clear any records from hashs */
5699static void clear_mod_from_hashes(struct ftrace_page *pg)
5700{
5701 struct trace_array *tr;
5702
5703 mutex_lock(&trace_types_lock);
5704 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5705 if (!tr->ops || !tr->ops->func_hash)
5706 continue;
5707 mutex_lock(&tr->ops->func_hash->regex_lock);
5708 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5709 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5710 mutex_unlock(&tr->ops->func_hash->regex_lock);
5711 }
5712 mutex_unlock(&trace_types_lock);
5713}
5714
5715static void ftrace_free_mod_map(struct rcu_head *rcu)
5716{
5717 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5718 struct ftrace_mod_func *mod_func;
5719 struct ftrace_mod_func *n;
5720
5721 /* All the contents of mod_map are now not visible to readers */
5722 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5723 kfree(mod_func->name);
5724 list_del(&mod_func->list);
5725 kfree(mod_func);
5726 }
5727
5728 kfree(mod_map);
5729}
5730
5731void ftrace_release_mod(struct module *mod)
5732{
5733 struct ftrace_mod_map *mod_map;
5734 struct ftrace_mod_map *n;
5735 struct dyn_ftrace *rec;
5736 struct ftrace_page **last_pg;
5737 struct ftrace_page *tmp_page = NULL;
5738 struct ftrace_page *pg;
5739 int order;
5740
5741 mutex_lock(&ftrace_lock);
5742
5743 if (ftrace_disabled)
5744 goto out_unlock;
5745
5746 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5747 if (mod_map->mod == mod) {
5748 list_del_rcu(&mod_map->list);
5749 call_rcu_sched(&mod_map->rcu, ftrace_free_mod_map);
5750 break;
5751 }
5752 }
5753
5754 /*
5755 * Each module has its own ftrace_pages, remove
5756 * them from the list.
5757 */
5758 last_pg = &ftrace_pages_start;
5759 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5760 rec = &pg->records[0];
5761 if (within_module_core(rec->ip, mod) ||
5762 within_module_init(rec->ip, mod)) {
5763 /*
5764 * As core pages are first, the first
5765 * page should never be a module page.
5766 */
5767 if (WARN_ON(pg == ftrace_pages_start))
5768 goto out_unlock;
5769
5770 /* Check if we are deleting the last page */
5771 if (pg == ftrace_pages)
5772 ftrace_pages = next_to_ftrace_page(last_pg);
5773
5774 ftrace_update_tot_cnt -= pg->index;
5775 *last_pg = pg->next;
5776
5777 pg->next = tmp_page;
5778 tmp_page = pg;
5779 } else
5780 last_pg = &pg->next;
5781 }
5782 out_unlock:
5783 mutex_unlock(&ftrace_lock);
5784
5785 for (pg = tmp_page; pg; pg = tmp_page) {
5786
5787 /* Needs to be called outside of ftrace_lock */
5788 clear_mod_from_hashes(pg);
5789
5790 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5791 free_pages((unsigned long)pg->records, order);
5792 tmp_page = pg->next;
5793 kfree(pg);
5794 }
5795}
5796
5797void ftrace_module_enable(struct module *mod)
5798{
5799 struct dyn_ftrace *rec;
5800 struct ftrace_page *pg;
5801
5802 mutex_lock(&ftrace_lock);
5803
5804 if (ftrace_disabled)
5805 goto out_unlock;
5806
5807 /*
5808 * If the tracing is enabled, go ahead and enable the record.
5809 *
5810 * The reason not to enable the record immediatelly is the
5811 * inherent check of ftrace_make_nop/ftrace_make_call for
5812 * correct previous instructions. Making first the NOP
5813 * conversion puts the module to the correct state, thus
5814 * passing the ftrace_make_call check.
5815 *
5816 * We also delay this to after the module code already set the
5817 * text to read-only, as we now need to set it back to read-write
5818 * so that we can modify the text.
5819 */
5820 if (ftrace_start_up)
5821 ftrace_arch_code_modify_prepare();
5822
5823 do_for_each_ftrace_rec(pg, rec) {
5824 int cnt;
5825 /*
5826 * do_for_each_ftrace_rec() is a double loop.
5827 * module text shares the pg. If a record is
5828 * not part of this module, then skip this pg,
5829 * which the "break" will do.
5830 */
5831 if (!within_module_core(rec->ip, mod) &&
5832 !within_module_init(rec->ip, mod))
5833 break;
5834
5835 cnt = 0;
5836
5837 /*
5838 * When adding a module, we need to check if tracers are
5839 * currently enabled and if they are, and can trace this record,
5840 * we need to enable the module functions as well as update the
5841 * reference counts for those function records.
5842 */
5843 if (ftrace_start_up)
5844 cnt += referenced_filters(rec);
5845
5846 /* This clears FTRACE_FL_DISABLED */
5847 rec->flags = cnt;
5848
5849 if (ftrace_start_up && cnt) {
5850 int failed = __ftrace_replace_code(rec, 1);
5851 if (failed) {
5852 ftrace_bug(failed, rec);
5853 goto out_loop;
5854 }
5855 }
5856
5857 } while_for_each_ftrace_rec();
5858
5859 out_loop:
5860 if (ftrace_start_up)
5861 ftrace_arch_code_modify_post_process();
5862
5863 out_unlock:
5864 mutex_unlock(&ftrace_lock);
5865
5866 process_cached_mods(mod->name);
5867}
5868
5869void ftrace_module_init(struct module *mod)
5870{
5871 if (ftrace_disabled || !mod->num_ftrace_callsites)
5872 return;
5873
5874 ftrace_process_locs(mod, mod->ftrace_callsites,
5875 mod->ftrace_callsites + mod->num_ftrace_callsites);
5876}
5877
5878static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5879 struct dyn_ftrace *rec)
5880{
5881 struct ftrace_mod_func *mod_func;
5882 unsigned long symsize;
5883 unsigned long offset;
5884 char str[KSYM_SYMBOL_LEN];
5885 char *modname;
5886 const char *ret;
5887
5888 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
5889 if (!ret)
5890 return;
5891
5892 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
5893 if (!mod_func)
5894 return;
5895
5896 mod_func->name = kstrdup(str, GFP_KERNEL);
5897 if (!mod_func->name) {
5898 kfree(mod_func);
5899 return;
5900 }
5901
5902 mod_func->ip = rec->ip - offset;
5903 mod_func->size = symsize;
5904
5905 mod_map->num_funcs++;
5906
5907 list_add_rcu(&mod_func->list, &mod_map->funcs);
5908}
5909
5910static struct ftrace_mod_map *
5911allocate_ftrace_mod_map(struct module *mod,
5912 unsigned long start, unsigned long end)
5913{
5914 struct ftrace_mod_map *mod_map;
5915
5916 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
5917 if (!mod_map)
5918 return NULL;
5919
5920 mod_map->mod = mod;
5921 mod_map->start_addr = start;
5922 mod_map->end_addr = end;
5923 mod_map->num_funcs = 0;
5924
5925 INIT_LIST_HEAD_RCU(&mod_map->funcs);
5926
5927 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
5928
5929 return mod_map;
5930}
5931
5932static const char *
5933ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
5934 unsigned long addr, unsigned long *size,
5935 unsigned long *off, char *sym)
5936{
5937 struct ftrace_mod_func *found_func = NULL;
5938 struct ftrace_mod_func *mod_func;
5939
5940 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5941 if (addr >= mod_func->ip &&
5942 addr < mod_func->ip + mod_func->size) {
5943 found_func = mod_func;
5944 break;
5945 }
5946 }
5947
5948 if (found_func) {
5949 if (size)
5950 *size = found_func->size;
5951 if (off)
5952 *off = addr - found_func->ip;
5953 if (sym)
5954 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
5955
5956 return found_func->name;
5957 }
5958
5959 return NULL;
5960}
5961
5962const char *
5963ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
5964 unsigned long *off, char **modname, char *sym)
5965{
5966 struct ftrace_mod_map *mod_map;
5967 const char *ret = NULL;
5968
5969 /* mod_map is freed via call_rcu_sched() */
5970 preempt_disable();
5971 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5972 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
5973 if (ret) {
5974 if (modname)
5975 *modname = mod_map->mod->name;
5976 break;
5977 }
5978 }
5979 preempt_enable();
5980
5981 return ret;
5982}
5983
5984int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
5985 char *type, char *name,
5986 char *module_name, int *exported)
5987{
5988 struct ftrace_mod_map *mod_map;
5989 struct ftrace_mod_func *mod_func;
5990
5991 preempt_disable();
5992 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5993
5994 if (symnum >= mod_map->num_funcs) {
5995 symnum -= mod_map->num_funcs;
5996 continue;
5997 }
5998
5999 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6000 if (symnum > 1) {
6001 symnum--;
6002 continue;
6003 }
6004
6005 *value = mod_func->ip;
6006 *type = 'T';
6007 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6008 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6009 *exported = 1;
6010 preempt_enable();
6011 return 0;
6012 }
6013 WARN_ON(1);
6014 break;
6015 }
6016 preempt_enable();
6017 return -ERANGE;
6018}
6019
6020#else
6021static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6022 struct dyn_ftrace *rec) { }
6023static inline struct ftrace_mod_map *
6024allocate_ftrace_mod_map(struct module *mod,
6025 unsigned long start, unsigned long end)
6026{
6027 return NULL;
6028}
6029#endif /* CONFIG_MODULES */
6030
6031struct ftrace_init_func {
6032 struct list_head list;
6033 unsigned long ip;
6034};
6035
6036/* Clear any init ips from hashes */
6037static void
6038clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6039{
6040 struct ftrace_func_entry *entry;
6041
6042 if (ftrace_hash_empty(hash))
6043 return;
6044
6045 entry = __ftrace_lookup_ip(hash, func->ip);
6046
6047 /*
6048 * Do not allow this rec to match again.
6049 * Yeah, it may waste some memory, but will be removed
6050 * if/when the hash is modified again.
6051 */
6052 if (entry)
6053 entry->ip = 0;
6054}
6055
6056static void
6057clear_func_from_hashes(struct ftrace_init_func *func)
6058{
6059 struct trace_array *tr;
6060
6061 mutex_lock(&trace_types_lock);
6062 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6063 if (!tr->ops || !tr->ops->func_hash)
6064 continue;
6065 mutex_lock(&tr->ops->func_hash->regex_lock);
6066 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6067 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6068 mutex_unlock(&tr->ops->func_hash->regex_lock);
6069 }
6070 mutex_unlock(&trace_types_lock);
6071}
6072
6073static void add_to_clear_hash_list(struct list_head *clear_list,
6074 struct dyn_ftrace *rec)
6075{
6076 struct ftrace_init_func *func;
6077
6078 func = kmalloc(sizeof(*func), GFP_KERNEL);
6079 if (!func) {
6080 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6081 return;
6082 }
6083
6084 func->ip = rec->ip;
6085 list_add(&func->list, clear_list);
6086}
6087
6088void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6089{
6090 unsigned long start = (unsigned long)(start_ptr);
6091 unsigned long end = (unsigned long)(end_ptr);
6092 struct ftrace_page **last_pg = &ftrace_pages_start;
6093 struct ftrace_page *pg;
6094 struct dyn_ftrace *rec;
6095 struct dyn_ftrace key;
6096 struct ftrace_mod_map *mod_map = NULL;
6097 struct ftrace_init_func *func, *func_next;
6098 struct list_head clear_hash;
6099 int order;
6100
6101 INIT_LIST_HEAD(&clear_hash);
6102
6103 key.ip = start;
6104 key.flags = end; /* overload flags, as it is unsigned long */
6105
6106 mutex_lock(&ftrace_lock);
6107
6108 /*
6109 * If we are freeing module init memory, then check if
6110 * any tracer is active. If so, we need to save a mapping of
6111 * the module functions being freed with the address.
6112 */
6113 if (mod && ftrace_ops_list != &ftrace_list_end)
6114 mod_map = allocate_ftrace_mod_map(mod, start, end);
6115
6116 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6117 if (end < pg->records[0].ip ||
6118 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6119 continue;
6120 again:
6121 rec = bsearch(&key, pg->records, pg->index,
6122 sizeof(struct dyn_ftrace),
6123 ftrace_cmp_recs);
6124 if (!rec)
6125 continue;
6126
6127 /* rec will be cleared from hashes after ftrace_lock unlock */
6128 add_to_clear_hash_list(&clear_hash, rec);
6129
6130 if (mod_map)
6131 save_ftrace_mod_rec(mod_map, rec);
6132
6133 pg->index--;
6134 ftrace_update_tot_cnt--;
6135 if (!pg->index) {
6136 *last_pg = pg->next;
6137 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6138 free_pages((unsigned long)pg->records, order);
6139 kfree(pg);
6140 pg = container_of(last_pg, struct ftrace_page, next);
6141 if (!(*last_pg))
6142 ftrace_pages = pg;
6143 continue;
6144 }
6145 memmove(rec, rec + 1,
6146 (pg->index - (rec - pg->records)) * sizeof(*rec));
6147 /* More than one function may be in this block */
6148 goto again;
6149 }
6150 mutex_unlock(&ftrace_lock);
6151
6152 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6153 clear_func_from_hashes(func);
6154 kfree(func);
6155 }
6156}
6157
6158void __init ftrace_free_init_mem(void)
6159{
6160 void *start = (void *)(&__init_begin);
6161 void *end = (void *)(&__init_end);
6162
6163 ftrace_free_mem(NULL, start, end);
6164}
6165
6166void __init ftrace_init(void)
6167{
6168 extern unsigned long __start_mcount_loc[];
6169 extern unsigned long __stop_mcount_loc[];
6170 unsigned long count, flags;
6171 int ret;
6172
6173 local_irq_save(flags);
6174 ret = ftrace_dyn_arch_init();
6175 local_irq_restore(flags);
6176 if (ret)
6177 goto failed;
6178
6179 count = __stop_mcount_loc - __start_mcount_loc;
6180 if (!count) {
6181 pr_info("ftrace: No functions to be traced?\n");
6182 goto failed;
6183 }
6184
6185 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6186 count, count / ENTRIES_PER_PAGE + 1);
6187
6188 last_ftrace_enabled = ftrace_enabled = 1;
6189
6190 ret = ftrace_process_locs(NULL,
6191 __start_mcount_loc,
6192 __stop_mcount_loc);
6193
6194 set_ftrace_early_filters();
6195
6196 return;
6197 failed:
6198 ftrace_disabled = 1;
6199}
6200
6201/* Do nothing if arch does not support this */
6202void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6203{
6204}
6205
6206static void ftrace_update_trampoline(struct ftrace_ops *ops)
6207{
6208 arch_ftrace_update_trampoline(ops);
6209}
6210
6211void ftrace_init_trace_array(struct trace_array *tr)
6212{
6213 INIT_LIST_HEAD(&tr->func_probes);
6214 INIT_LIST_HEAD(&tr->mod_trace);
6215 INIT_LIST_HEAD(&tr->mod_notrace);
6216}
6217#else
6218
6219static struct ftrace_ops global_ops = {
6220 .func = ftrace_stub,
6221 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6222 FTRACE_OPS_FL_INITIALIZED |
6223 FTRACE_OPS_FL_PID,
6224};
6225
6226static int __init ftrace_nodyn_init(void)
6227{
6228 ftrace_enabled = 1;
6229 return 0;
6230}
6231core_initcall(ftrace_nodyn_init);
6232
6233static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6234static inline void ftrace_startup_enable(int command) { }
6235static inline void ftrace_startup_all(int command) { }
6236/* Keep as macros so we do not need to define the commands */
6237# define ftrace_startup(ops, command) \
6238 ({ \
6239 int ___ret = __register_ftrace_function(ops); \
6240 if (!___ret) \
6241 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
6242 ___ret; \
6243 })
6244# define ftrace_shutdown(ops, command) \
6245 ({ \
6246 int ___ret = __unregister_ftrace_function(ops); \
6247 if (!___ret) \
6248 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
6249 ___ret; \
6250 })
6251
6252# define ftrace_startup_sysctl() do { } while (0)
6253# define ftrace_shutdown_sysctl() do { } while (0)
6254
6255static inline int
6256ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
6257{
6258 return 1;
6259}
6260
6261static void ftrace_update_trampoline(struct ftrace_ops *ops)
6262{
6263}
6264
6265#endif /* CONFIG_DYNAMIC_FTRACE */
6266
6267__init void ftrace_init_global_array_ops(struct trace_array *tr)
6268{
6269 tr->ops = &global_ops;
6270 tr->ops->private = tr;
6271 ftrace_init_trace_array(tr);
6272}
6273
6274void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6275{
6276 /* If we filter on pids, update to use the pid function */
6277 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6278 if (WARN_ON(tr->ops->func != ftrace_stub))
6279 printk("ftrace ops had %pS for function\n",
6280 tr->ops->func);
6281 }
6282 tr->ops->func = func;
6283 tr->ops->private = tr;
6284}
6285
6286void ftrace_reset_array_ops(struct trace_array *tr)
6287{
6288 tr->ops->func = ftrace_stub;
6289}
6290
6291static inline void
6292__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6293 struct ftrace_ops *ignored, struct pt_regs *regs)
6294{
6295 struct ftrace_ops *op;
6296 int bit;
6297
6298 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6299 if (bit < 0)
6300 return;
6301
6302 /*
6303 * Some of the ops may be dynamically allocated,
6304 * they must be freed after a synchronize_sched().
6305 */
6306 preempt_disable_notrace();
6307
6308 do_for_each_ftrace_op(op, ftrace_ops_list) {
6309 /*
6310 * Check the following for each ops before calling their func:
6311 * if RCU flag is set, then rcu_is_watching() must be true
6312 * if PER_CPU is set, then ftrace_function_local_disable()
6313 * must be false
6314 * Otherwise test if the ip matches the ops filter
6315 *
6316 * If any of the above fails then the op->func() is not executed.
6317 */
6318 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6319 ftrace_ops_test(op, ip, regs)) {
6320 if (FTRACE_WARN_ON(!op->func)) {
6321 pr_warn("op=%p %pS\n", op, op);
6322 goto out;
6323 }
6324 op->func(ip, parent_ip, op, regs);
6325 }
6326 } while_for_each_ftrace_op(op);
6327out:
6328 preempt_enable_notrace();
6329 trace_clear_recursion(bit);
6330}
6331
6332/*
6333 * Some archs only support passing ip and parent_ip. Even though
6334 * the list function ignores the op parameter, we do not want any
6335 * C side effects, where a function is called without the caller
6336 * sending a third parameter.
6337 * Archs are to support both the regs and ftrace_ops at the same time.
6338 * If they support ftrace_ops, it is assumed they support regs.
6339 * If call backs want to use regs, they must either check for regs
6340 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6341 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6342 * An architecture can pass partial regs with ftrace_ops and still
6343 * set the ARCH_SUPPORTS_FTRACE_OPS.
6344 */
6345#if ARCH_SUPPORTS_FTRACE_OPS
6346static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6347 struct ftrace_ops *op, struct pt_regs *regs)
6348{
6349 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6350}
6351#else
6352static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6353{
6354 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6355}
6356#endif
6357
6358/*
6359 * If there's only one function registered but it does not support
6360 * recursion, needs RCU protection and/or requires per cpu handling, then
6361 * this function will be called by the mcount trampoline.
6362 */
6363static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6364 struct ftrace_ops *op, struct pt_regs *regs)
6365{
6366 int bit;
6367
6368 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6369 return;
6370
6371 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6372 if (bit < 0)
6373 return;
6374
6375 preempt_disable_notrace();
6376
6377 op->func(ip, parent_ip, op, regs);
6378
6379 preempt_enable_notrace();
6380 trace_clear_recursion(bit);
6381}
6382
6383/**
6384 * ftrace_ops_get_func - get the function a trampoline should call
6385 * @ops: the ops to get the function for
6386 *
6387 * Normally the mcount trampoline will call the ops->func, but there
6388 * are times that it should not. For example, if the ops does not
6389 * have its own recursion protection, then it should call the
6390 * ftrace_ops_assist_func() instead.
6391 *
6392 * Returns the function that the trampoline should call for @ops.
6393 */
6394ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6395{
6396 /*
6397 * If the function does not handle recursion, needs to be RCU safe,
6398 * or does per cpu logic, then we need to call the assist handler.
6399 */
6400 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6401 ops->flags & FTRACE_OPS_FL_RCU)
6402 return ftrace_ops_assist_func;
6403
6404 return ops->func;
6405}
6406
6407static void
6408ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6409 struct task_struct *prev, struct task_struct *next)
6410{
6411 struct trace_array *tr = data;
6412 struct trace_pid_list *pid_list;
6413
6414 pid_list = rcu_dereference_sched(tr->function_pids);
6415
6416 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6417 trace_ignore_this_task(pid_list, next));
6418}
6419
6420static void
6421ftrace_pid_follow_sched_process_fork(void *data,
6422 struct task_struct *self,
6423 struct task_struct *task)
6424{
6425 struct trace_pid_list *pid_list;
6426 struct trace_array *tr = data;
6427
6428 pid_list = rcu_dereference_sched(tr->function_pids);
6429 trace_filter_add_remove_task(pid_list, self, task);
6430}
6431
6432static void
6433ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6434{
6435 struct trace_pid_list *pid_list;
6436 struct trace_array *tr = data;
6437
6438 pid_list = rcu_dereference_sched(tr->function_pids);
6439 trace_filter_add_remove_task(pid_list, NULL, task);
6440}
6441
6442void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6443{
6444 if (enable) {
6445 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6446 tr);
6447 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6448 tr);
6449 } else {
6450 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6451 tr);
6452 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6453 tr);
6454 }
6455}
6456
6457static void clear_ftrace_pids(struct trace_array *tr)
6458{
6459 struct trace_pid_list *pid_list;
6460 int cpu;
6461
6462 pid_list = rcu_dereference_protected(tr->function_pids,
6463 lockdep_is_held(&ftrace_lock));
6464 if (!pid_list)
6465 return;
6466
6467 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6468
6469 for_each_possible_cpu(cpu)
6470 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6471
6472 rcu_assign_pointer(tr->function_pids, NULL);
6473
6474 /* Wait till all users are no longer using pid filtering */
6475 synchronize_sched();
6476
6477 trace_free_pid_list(pid_list);
6478}
6479
6480void ftrace_clear_pids(struct trace_array *tr)
6481{
6482 mutex_lock(&ftrace_lock);
6483
6484 clear_ftrace_pids(tr);
6485
6486 mutex_unlock(&ftrace_lock);
6487}
6488
6489static void ftrace_pid_reset(struct trace_array *tr)
6490{
6491 mutex_lock(&ftrace_lock);
6492 clear_ftrace_pids(tr);
6493
6494 ftrace_update_pid_func();
6495 ftrace_startup_all(0);
6496
6497 mutex_unlock(&ftrace_lock);
6498}
6499
6500/* Greater than any max PID */
6501#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6502
6503static void *fpid_start(struct seq_file *m, loff_t *pos)
6504 __acquires(RCU)
6505{
6506 struct trace_pid_list *pid_list;
6507 struct trace_array *tr = m->private;
6508
6509 mutex_lock(&ftrace_lock);
6510 rcu_read_lock_sched();
6511
6512 pid_list = rcu_dereference_sched(tr->function_pids);
6513
6514 if (!pid_list)
6515 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6516
6517 return trace_pid_start(pid_list, pos);
6518}
6519
6520static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6521{
6522 struct trace_array *tr = m->private;
6523 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6524
6525 if (v == FTRACE_NO_PIDS)
6526 return NULL;
6527
6528 return trace_pid_next(pid_list, v, pos);
6529}
6530
6531static void fpid_stop(struct seq_file *m, void *p)
6532 __releases(RCU)
6533{
6534 rcu_read_unlock_sched();
6535 mutex_unlock(&ftrace_lock);
6536}
6537
6538static int fpid_show(struct seq_file *m, void *v)
6539{
6540 if (v == FTRACE_NO_PIDS) {
6541 seq_puts(m, "no pid\n");
6542 return 0;
6543 }
6544
6545 return trace_pid_show(m, v);
6546}
6547
6548static const struct seq_operations ftrace_pid_sops = {
6549 .start = fpid_start,
6550 .next = fpid_next,
6551 .stop = fpid_stop,
6552 .show = fpid_show,
6553};
6554
6555static int
6556ftrace_pid_open(struct inode *inode, struct file *file)
6557{
6558 struct trace_array *tr = inode->i_private;
6559 struct seq_file *m;
6560 int ret = 0;
6561
6562 if (trace_array_get(tr) < 0)
6563 return -ENODEV;
6564
6565 if ((file->f_mode & FMODE_WRITE) &&
6566 (file->f_flags & O_TRUNC))
6567 ftrace_pid_reset(tr);
6568
6569 ret = seq_open(file, &ftrace_pid_sops);
6570 if (ret < 0) {
6571 trace_array_put(tr);
6572 } else {
6573 m = file->private_data;
6574 /* copy tr over to seq ops */
6575 m->private = tr;
6576 }
6577
6578 return ret;
6579}
6580
6581static void ignore_task_cpu(void *data)
6582{
6583 struct trace_array *tr = data;
6584 struct trace_pid_list *pid_list;
6585
6586 /*
6587 * This function is called by on_each_cpu() while the
6588 * event_mutex is held.
6589 */
6590 pid_list = rcu_dereference_protected(tr->function_pids,
6591 mutex_is_locked(&ftrace_lock));
6592
6593 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6594 trace_ignore_this_task(pid_list, current));
6595}
6596
6597static ssize_t
6598ftrace_pid_write(struct file *filp, const char __user *ubuf,
6599 size_t cnt, loff_t *ppos)
6600{
6601 struct seq_file *m = filp->private_data;
6602 struct trace_array *tr = m->private;
6603 struct trace_pid_list *filtered_pids = NULL;
6604 struct trace_pid_list *pid_list;
6605 ssize_t ret;
6606
6607 if (!cnt)
6608 return 0;
6609
6610 mutex_lock(&ftrace_lock);
6611
6612 filtered_pids = rcu_dereference_protected(tr->function_pids,
6613 lockdep_is_held(&ftrace_lock));
6614
6615 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6616 if (ret < 0)
6617 goto out;
6618
6619 rcu_assign_pointer(tr->function_pids, pid_list);
6620
6621 if (filtered_pids) {
6622 synchronize_sched();
6623 trace_free_pid_list(filtered_pids);
6624 } else if (pid_list) {
6625 /* Register a probe to set whether to ignore the tracing of a task */
6626 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6627 }
6628
6629 /*
6630 * Ignoring of pids is done at task switch. But we have to
6631 * check for those tasks that are currently running.
6632 * Always do this in case a pid was appended or removed.
6633 */
6634 on_each_cpu(ignore_task_cpu, tr, 1);
6635
6636 ftrace_update_pid_func();
6637 ftrace_startup_all(0);
6638 out:
6639 mutex_unlock(&ftrace_lock);
6640
6641 if (ret > 0)
6642 *ppos += ret;
6643
6644 return ret;
6645}
6646
6647static int
6648ftrace_pid_release(struct inode *inode, struct file *file)
6649{
6650 struct trace_array *tr = inode->i_private;
6651
6652 trace_array_put(tr);
6653
6654 return seq_release(inode, file);
6655}
6656
6657static const struct file_operations ftrace_pid_fops = {
6658 .open = ftrace_pid_open,
6659 .write = ftrace_pid_write,
6660 .read = seq_read,
6661 .llseek = tracing_lseek,
6662 .release = ftrace_pid_release,
6663};
6664
6665void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6666{
6667 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6668 tr, &ftrace_pid_fops);
6669}
6670
6671void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6672 struct dentry *d_tracer)
6673{
6674 /* Only the top level directory has the dyn_tracefs and profile */
6675 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6676
6677 ftrace_init_dyn_tracefs(d_tracer);
6678 ftrace_profile_tracefs(d_tracer);
6679}
6680
6681/**
6682 * ftrace_kill - kill ftrace
6683 *
6684 * This function should be used by panic code. It stops ftrace
6685 * but in a not so nice way. If you need to simply kill ftrace
6686 * from a non-atomic section, use ftrace_kill.
6687 */
6688void ftrace_kill(void)
6689{
6690 ftrace_disabled = 1;
6691 ftrace_enabled = 0;
6692 clear_ftrace_function();
6693}
6694
6695/**
6696 * Test if ftrace is dead or not.
6697 */
6698int ftrace_is_dead(void)
6699{
6700 return ftrace_disabled;
6701}
6702
6703/**
6704 * register_ftrace_function - register a function for profiling
6705 * @ops - ops structure that holds the function for profiling.
6706 *
6707 * Register a function to be called by all functions in the
6708 * kernel.
6709 *
6710 * Note: @ops->func and all the functions it calls must be labeled
6711 * with "notrace", otherwise it will go into a
6712 * recursive loop.
6713 */
6714int register_ftrace_function(struct ftrace_ops *ops)
6715{
6716 int ret = -1;
6717
6718 ftrace_ops_init(ops);
6719
6720 mutex_lock(&ftrace_lock);
6721
6722 ret = ftrace_startup(ops, 0);
6723
6724 mutex_unlock(&ftrace_lock);
6725
6726 return ret;
6727}
6728EXPORT_SYMBOL_GPL(register_ftrace_function);
6729
6730/**
6731 * unregister_ftrace_function - unregister a function for profiling.
6732 * @ops - ops structure that holds the function to unregister
6733 *
6734 * Unregister a function that was added to be called by ftrace profiling.
6735 */
6736int unregister_ftrace_function(struct ftrace_ops *ops)
6737{
6738 int ret;
6739
6740 mutex_lock(&ftrace_lock);
6741 ret = ftrace_shutdown(ops, 0);
6742 mutex_unlock(&ftrace_lock);
6743
6744 return ret;
6745}
6746EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6747
6748int
6749ftrace_enable_sysctl(struct ctl_table *table, int write,
6750 void __user *buffer, size_t *lenp,
6751 loff_t *ppos)
6752{
6753 int ret = -ENODEV;
6754
6755 mutex_lock(&ftrace_lock);
6756
6757 if (unlikely(ftrace_disabled))
6758 goto out;
6759
6760 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6761
6762 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6763 goto out;
6764
6765 last_ftrace_enabled = !!ftrace_enabled;
6766
6767 if (ftrace_enabled) {
6768
6769 /* we are starting ftrace again */
6770 if (rcu_dereference_protected(ftrace_ops_list,
6771 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6772 update_ftrace_function();
6773
6774 ftrace_startup_sysctl();
6775
6776 } else {
6777 /* stopping ftrace calls (just send to ftrace_stub) */
6778 ftrace_trace_function = ftrace_stub;
6779
6780 ftrace_shutdown_sysctl();
6781 }
6782
6783 out:
6784 mutex_unlock(&ftrace_lock);
6785 return ret;
6786}
6787
6788#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6789
6790static struct ftrace_ops graph_ops = {
6791 .func = ftrace_stub,
6792 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6793 FTRACE_OPS_FL_INITIALIZED |
6794 FTRACE_OPS_FL_PID |
6795 FTRACE_OPS_FL_STUB,
6796#ifdef FTRACE_GRAPH_TRAMP_ADDR
6797 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
6798 /* trampoline_size is only needed for dynamically allocated tramps */
6799#endif
6800 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
6801};
6802
6803void ftrace_graph_sleep_time_control(bool enable)
6804{
6805 fgraph_sleep_time = enable;
6806}
6807
6808void ftrace_graph_graph_time_control(bool enable)
6809{
6810 fgraph_graph_time = enable;
6811}
6812
6813int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
6814{
6815 return 0;
6816}
6817
6818/* The callbacks that hook a function */
6819trace_func_graph_ret_t ftrace_graph_return =
6820 (trace_func_graph_ret_t)ftrace_stub;
6821trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
6822static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
6823
6824/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
6825static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
6826{
6827 int i;
6828 int ret = 0;
6829 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
6830 struct task_struct *g, *t;
6831
6832 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
6833 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
6834 * sizeof(struct ftrace_ret_stack),
6835 GFP_KERNEL);
6836 if (!ret_stack_list[i]) {
6837 start = 0;
6838 end = i;
6839 ret = -ENOMEM;
6840 goto free;
6841 }
6842 }
6843
6844 read_lock(&tasklist_lock);
6845 do_each_thread(g, t) {
6846 if (start == end) {
6847 ret = -EAGAIN;
6848 goto unlock;
6849 }
6850
6851 if (t->ret_stack == NULL) {
6852 atomic_set(&t->tracing_graph_pause, 0);
6853 atomic_set(&t->trace_overrun, 0);
6854 t->curr_ret_stack = -1;
6855 /* Make sure the tasks see the -1 first: */
6856 smp_wmb();
6857 t->ret_stack = ret_stack_list[start++];
6858 }
6859 } while_each_thread(g, t);
6860
6861unlock:
6862 read_unlock(&tasklist_lock);
6863free:
6864 for (i = start; i < end; i++)
6865 kfree(ret_stack_list[i]);
6866 return ret;
6867}
6868
6869static void
6870ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
6871 struct task_struct *prev, struct task_struct *next)
6872{
6873 unsigned long long timestamp;
6874 int index;
6875
6876 /*
6877 * Does the user want to count the time a function was asleep.
6878 * If so, do not update the time stamps.
6879 */
6880 if (fgraph_sleep_time)
6881 return;
6882
6883 timestamp = trace_clock_local();
6884
6885 prev->ftrace_timestamp = timestamp;
6886
6887 /* only process tasks that we timestamped */
6888 if (!next->ftrace_timestamp)
6889 return;
6890
6891 /*
6892 * Update all the counters in next to make up for the
6893 * time next was sleeping.
6894 */
6895 timestamp -= next->ftrace_timestamp;
6896
6897 for (index = next->curr_ret_stack; index >= 0; index--)
6898 next->ret_stack[index].calltime += timestamp;
6899}
6900
6901/* Allocate a return stack for each task */
6902static int start_graph_tracing(void)
6903{
6904 struct ftrace_ret_stack **ret_stack_list;
6905 int ret, cpu;
6906
6907 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
6908 sizeof(struct ftrace_ret_stack *),
6909 GFP_KERNEL);
6910
6911 if (!ret_stack_list)
6912 return -ENOMEM;
6913
6914 /* The cpu_boot init_task->ret_stack will never be freed */
6915 for_each_online_cpu(cpu) {
6916 if (!idle_task(cpu)->ret_stack)
6917 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
6918 }
6919
6920 do {
6921 ret = alloc_retstack_tasklist(ret_stack_list);
6922 } while (ret == -EAGAIN);
6923
6924 if (!ret) {
6925 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6926 if (ret)
6927 pr_info("ftrace_graph: Couldn't activate tracepoint"
6928 " probe to kernel_sched_switch\n");
6929 }
6930
6931 kfree(ret_stack_list);
6932 return ret;
6933}
6934
6935/*
6936 * Hibernation protection.
6937 * The state of the current task is too much unstable during
6938 * suspend/restore to disk. We want to protect against that.
6939 */
6940static int
6941ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
6942 void *unused)
6943{
6944 switch (state) {
6945 case PM_HIBERNATION_PREPARE:
6946 pause_graph_tracing();
6947 break;
6948
6949 case PM_POST_HIBERNATION:
6950 unpause_graph_tracing();
6951 break;
6952 }
6953 return NOTIFY_DONE;
6954}
6955
6956static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
6957{
6958 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
6959 return 0;
6960 return __ftrace_graph_entry(trace);
6961}
6962
6963/*
6964 * The function graph tracer should only trace the functions defined
6965 * by set_ftrace_filter and set_ftrace_notrace. If another function
6966 * tracer ops is registered, the graph tracer requires testing the
6967 * function against the global ops, and not just trace any function
6968 * that any ftrace_ops registered.
6969 */
6970static void update_function_graph_func(void)
6971{
6972 struct ftrace_ops *op;
6973 bool do_test = false;
6974
6975 /*
6976 * The graph and global ops share the same set of functions
6977 * to test. If any other ops is on the list, then
6978 * the graph tracing needs to test if its the function
6979 * it should call.
6980 */
6981 do_for_each_ftrace_op(op, ftrace_ops_list) {
6982 if (op != &global_ops && op != &graph_ops &&
6983 op != &ftrace_list_end) {
6984 do_test = true;
6985 /* in double loop, break out with goto */
6986 goto out;
6987 }
6988 } while_for_each_ftrace_op(op);
6989 out:
6990 if (do_test)
6991 ftrace_graph_entry = ftrace_graph_entry_test;
6992 else
6993 ftrace_graph_entry = __ftrace_graph_entry;
6994}
6995
6996static struct notifier_block ftrace_suspend_notifier = {
6997 .notifier_call = ftrace_suspend_notifier_call,
6998};
6999
7000int register_ftrace_graph(trace_func_graph_ret_t retfunc,
7001 trace_func_graph_ent_t entryfunc)
7002{
7003 int ret = 0;
7004
7005 mutex_lock(&ftrace_lock);
7006
7007 /* we currently allow only one tracer registered at a time */
7008 if (ftrace_graph_active) {
7009 ret = -EBUSY;
7010 goto out;
7011 }
7012
7013 register_pm_notifier(&ftrace_suspend_notifier);
7014
7015 ftrace_graph_active++;
7016 ret = start_graph_tracing();
7017 if (ret) {
7018 ftrace_graph_active--;
7019 goto out;
7020 }
7021
7022 ftrace_graph_return = retfunc;
7023
7024 /*
7025 * Update the indirect function to the entryfunc, and the
7026 * function that gets called to the entry_test first. Then
7027 * call the update fgraph entry function to determine if
7028 * the entryfunc should be called directly or not.
7029 */
7030 __ftrace_graph_entry = entryfunc;
7031 ftrace_graph_entry = ftrace_graph_entry_test;
7032 update_function_graph_func();
7033
7034 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
7035out:
7036 mutex_unlock(&ftrace_lock);
7037 return ret;
7038}
7039
7040void unregister_ftrace_graph(void)
7041{
7042 mutex_lock(&ftrace_lock);
7043
7044 if (unlikely(!ftrace_graph_active))
7045 goto out;
7046
7047 ftrace_graph_active--;
7048 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
7049 ftrace_graph_entry = ftrace_graph_entry_stub;
7050 __ftrace_graph_entry = ftrace_graph_entry_stub;
7051 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
7052 unregister_pm_notifier(&ftrace_suspend_notifier);
7053 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
7054
7055 out:
7056 mutex_unlock(&ftrace_lock);
7057}
7058
7059static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
7060
7061static void
7062graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
7063{
7064 atomic_set(&t->tracing_graph_pause, 0);
7065 atomic_set(&t->trace_overrun, 0);
7066 t->ftrace_timestamp = 0;
7067 /* make curr_ret_stack visible before we add the ret_stack */
7068 smp_wmb();
7069 t->ret_stack = ret_stack;
7070}
7071
7072/*
7073 * Allocate a return stack for the idle task. May be the first
7074 * time through, or it may be done by CPU hotplug online.
7075 */
7076void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
7077{
7078 t->curr_ret_stack = -1;
7079 /*
7080 * The idle task has no parent, it either has its own
7081 * stack or no stack at all.
7082 */
7083 if (t->ret_stack)
7084 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
7085
7086 if (ftrace_graph_active) {
7087 struct ftrace_ret_stack *ret_stack;
7088
7089 ret_stack = per_cpu(idle_ret_stack, cpu);
7090 if (!ret_stack) {
7091 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
7092 * sizeof(struct ftrace_ret_stack),
7093 GFP_KERNEL);
7094 if (!ret_stack)
7095 return;
7096 per_cpu(idle_ret_stack, cpu) = ret_stack;
7097 }
7098 graph_init_task(t, ret_stack);
7099 }
7100}
7101
7102/* Allocate a return stack for newly created task */
7103void ftrace_graph_init_task(struct task_struct *t)
7104{
7105 /* Make sure we do not use the parent ret_stack */
7106 t->ret_stack = NULL;
7107 t->curr_ret_stack = -1;
7108
7109 if (ftrace_graph_active) {
7110 struct ftrace_ret_stack *ret_stack;
7111
7112 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
7113 * sizeof(struct ftrace_ret_stack),
7114 GFP_KERNEL);
7115 if (!ret_stack)
7116 return;
7117 graph_init_task(t, ret_stack);
7118 }
7119}
7120
7121void ftrace_graph_exit_task(struct task_struct *t)
7122{
7123 struct ftrace_ret_stack *ret_stack = t->ret_stack;
7124
7125 t->ret_stack = NULL;
7126 /* NULL must become visible to IRQs before we free it: */
7127 barrier();
7128
7129 kfree(ret_stack);
7130}
7131#endif
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code in the latency_tracer, that is:
12 *
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
15 */
16
17#include <linux/stop_machine.h>
18#include <linux/clocksource.h>
19#include <linux/sched/task.h>
20#include <linux/kallsyms.h>
21#include <linux/security.h>
22#include <linux/seq_file.h>
23#include <linux/tracefs.h>
24#include <linux/hardirq.h>
25#include <linux/kthread.h>
26#include <linux/uaccess.h>
27#include <linux/bsearch.h>
28#include <linux/module.h>
29#include <linux/ftrace.h>
30#include <linux/sysctl.h>
31#include <linux/slab.h>
32#include <linux/ctype.h>
33#include <linux/sort.h>
34#include <linux/list.h>
35#include <linux/hash.h>
36#include <linux/rcupdate.h>
37#include <linux/kprobes.h>
38
39#include <trace/events/sched.h>
40
41#include <asm/sections.h>
42#include <asm/setup.h>
43
44#include "ftrace_internal.h"
45#include "trace_output.h"
46#include "trace_stat.h"
47
48/* Flags that do not get reset */
49#define FTRACE_NOCLEAR_FLAGS (FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
50 FTRACE_FL_MODIFIED)
51
52#define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
53
54#define FTRACE_WARN_ON(cond) \
55 ({ \
56 int ___r = cond; \
57 if (WARN_ON(___r)) \
58 ftrace_kill(); \
59 ___r; \
60 })
61
62#define FTRACE_WARN_ON_ONCE(cond) \
63 ({ \
64 int ___r = cond; \
65 if (WARN_ON_ONCE(___r)) \
66 ftrace_kill(); \
67 ___r; \
68 })
69
70/* hash bits for specific function selection */
71#define FTRACE_HASH_DEFAULT_BITS 10
72#define FTRACE_HASH_MAX_BITS 12
73
74#ifdef CONFIG_DYNAMIC_FTRACE
75#define INIT_OPS_HASH(opsname) \
76 .func_hash = &opsname.local_hash, \
77 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
78#else
79#define INIT_OPS_HASH(opsname)
80#endif
81
82enum {
83 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
84 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
85};
86
87struct ftrace_ops ftrace_list_end __read_mostly = {
88 .func = ftrace_stub,
89 .flags = FTRACE_OPS_FL_STUB,
90 INIT_OPS_HASH(ftrace_list_end)
91};
92
93/* ftrace_enabled is a method to turn ftrace on or off */
94int ftrace_enabled __read_mostly;
95static int __maybe_unused last_ftrace_enabled;
96
97/* Current function tracing op */
98struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
99/* What to set function_trace_op to */
100static struct ftrace_ops *set_function_trace_op;
101
102static bool ftrace_pids_enabled(struct ftrace_ops *ops)
103{
104 struct trace_array *tr;
105
106 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
107 return false;
108
109 tr = ops->private;
110
111 return tr->function_pids != NULL || tr->function_no_pids != NULL;
112}
113
114static void ftrace_update_trampoline(struct ftrace_ops *ops);
115
116/*
117 * ftrace_disabled is set when an anomaly is discovered.
118 * ftrace_disabled is much stronger than ftrace_enabled.
119 */
120static int ftrace_disabled __read_mostly;
121
122DEFINE_MUTEX(ftrace_lock);
123
124struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
125ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
126struct ftrace_ops global_ops;
127
128/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
129void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
130 struct ftrace_ops *op, struct ftrace_regs *fregs);
131
132#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
133/*
134 * Stub used to invoke the list ops without requiring a separate trampoline.
135 */
136const struct ftrace_ops ftrace_list_ops = {
137 .func = ftrace_ops_list_func,
138 .flags = FTRACE_OPS_FL_STUB,
139};
140
141static void ftrace_ops_nop_func(unsigned long ip, unsigned long parent_ip,
142 struct ftrace_ops *op,
143 struct ftrace_regs *fregs)
144{
145 /* do nothing */
146}
147
148/*
149 * Stub used when a call site is disabled. May be called transiently by threads
150 * which have made it into ftrace_caller but haven't yet recovered the ops at
151 * the point the call site is disabled.
152 */
153const struct ftrace_ops ftrace_nop_ops = {
154 .func = ftrace_ops_nop_func,
155 .flags = FTRACE_OPS_FL_STUB,
156};
157#endif
158
159static inline void ftrace_ops_init(struct ftrace_ops *ops)
160{
161#ifdef CONFIG_DYNAMIC_FTRACE
162 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
163 mutex_init(&ops->local_hash.regex_lock);
164 ops->func_hash = &ops->local_hash;
165 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
166 }
167#endif
168}
169
170static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
171 struct ftrace_ops *op, struct ftrace_regs *fregs)
172{
173 struct trace_array *tr = op->private;
174 int pid;
175
176 if (tr) {
177 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
178 if (pid == FTRACE_PID_IGNORE)
179 return;
180 if (pid != FTRACE_PID_TRACE &&
181 pid != current->pid)
182 return;
183 }
184
185 op->saved_func(ip, parent_ip, op, fregs);
186}
187
188static void ftrace_sync_ipi(void *data)
189{
190 /* Probably not needed, but do it anyway */
191 smp_rmb();
192}
193
194static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
195{
196 /*
197 * If this is a dynamic or RCU ops, or we force list func,
198 * then it needs to call the list anyway.
199 */
200 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
201 FTRACE_FORCE_LIST_FUNC)
202 return ftrace_ops_list_func;
203
204 return ftrace_ops_get_func(ops);
205}
206
207static void update_ftrace_function(void)
208{
209 ftrace_func_t func;
210
211 /*
212 * Prepare the ftrace_ops that the arch callback will use.
213 * If there's only one ftrace_ops registered, the ftrace_ops_list
214 * will point to the ops we want.
215 */
216 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
217 lockdep_is_held(&ftrace_lock));
218
219 /* If there's no ftrace_ops registered, just call the stub function */
220 if (set_function_trace_op == &ftrace_list_end) {
221 func = ftrace_stub;
222
223 /*
224 * If we are at the end of the list and this ops is
225 * recursion safe and not dynamic and the arch supports passing ops,
226 * then have the mcount trampoline call the function directly.
227 */
228 } else if (rcu_dereference_protected(ftrace_ops_list->next,
229 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
230 func = ftrace_ops_get_list_func(ftrace_ops_list);
231
232 } else {
233 /* Just use the default ftrace_ops */
234 set_function_trace_op = &ftrace_list_end;
235 func = ftrace_ops_list_func;
236 }
237
238 update_function_graph_func();
239
240 /* If there's no change, then do nothing more here */
241 if (ftrace_trace_function == func)
242 return;
243
244 /*
245 * If we are using the list function, it doesn't care
246 * about the function_trace_ops.
247 */
248 if (func == ftrace_ops_list_func) {
249 ftrace_trace_function = func;
250 /*
251 * Don't even bother setting function_trace_ops,
252 * it would be racy to do so anyway.
253 */
254 return;
255 }
256
257#ifndef CONFIG_DYNAMIC_FTRACE
258 /*
259 * For static tracing, we need to be a bit more careful.
260 * The function change takes affect immediately. Thus,
261 * we need to coordinate the setting of the function_trace_ops
262 * with the setting of the ftrace_trace_function.
263 *
264 * Set the function to the list ops, which will call the
265 * function we want, albeit indirectly, but it handles the
266 * ftrace_ops and doesn't depend on function_trace_op.
267 */
268 ftrace_trace_function = ftrace_ops_list_func;
269 /*
270 * Make sure all CPUs see this. Yes this is slow, but static
271 * tracing is slow and nasty to have enabled.
272 */
273 synchronize_rcu_tasks_rude();
274 /* Now all cpus are using the list ops. */
275 function_trace_op = set_function_trace_op;
276 /* Make sure the function_trace_op is visible on all CPUs */
277 smp_wmb();
278 /* Nasty way to force a rmb on all cpus */
279 smp_call_function(ftrace_sync_ipi, NULL, 1);
280 /* OK, we are all set to update the ftrace_trace_function now! */
281#endif /* !CONFIG_DYNAMIC_FTRACE */
282
283 ftrace_trace_function = func;
284}
285
286static void add_ftrace_ops(struct ftrace_ops __rcu **list,
287 struct ftrace_ops *ops)
288{
289 rcu_assign_pointer(ops->next, *list);
290
291 /*
292 * We are entering ops into the list but another
293 * CPU might be walking that list. We need to make sure
294 * the ops->next pointer is valid before another CPU sees
295 * the ops pointer included into the list.
296 */
297 rcu_assign_pointer(*list, ops);
298}
299
300static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
301 struct ftrace_ops *ops)
302{
303 struct ftrace_ops **p;
304
305 /*
306 * If we are removing the last function, then simply point
307 * to the ftrace_stub.
308 */
309 if (rcu_dereference_protected(*list,
310 lockdep_is_held(&ftrace_lock)) == ops &&
311 rcu_dereference_protected(ops->next,
312 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
313 *list = &ftrace_list_end;
314 return 0;
315 }
316
317 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
318 if (*p == ops)
319 break;
320
321 if (*p != ops)
322 return -1;
323
324 *p = (*p)->next;
325 return 0;
326}
327
328static void ftrace_update_trampoline(struct ftrace_ops *ops);
329
330int __register_ftrace_function(struct ftrace_ops *ops)
331{
332 if (ops->flags & FTRACE_OPS_FL_DELETED)
333 return -EINVAL;
334
335 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
336 return -EBUSY;
337
338#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
339 /*
340 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
341 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
342 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
343 */
344 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
345 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
346 return -EINVAL;
347
348 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
349 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
350#endif
351 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
352 return -EBUSY;
353
354 if (!is_kernel_core_data((unsigned long)ops))
355 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
356
357 add_ftrace_ops(&ftrace_ops_list, ops);
358
359 /* Always save the function, and reset at unregistering */
360 ops->saved_func = ops->func;
361
362 if (ftrace_pids_enabled(ops))
363 ops->func = ftrace_pid_func;
364
365 ftrace_update_trampoline(ops);
366
367 if (ftrace_enabled)
368 update_ftrace_function();
369
370 return 0;
371}
372
373int __unregister_ftrace_function(struct ftrace_ops *ops)
374{
375 int ret;
376
377 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
378 return -EBUSY;
379
380 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
381
382 if (ret < 0)
383 return ret;
384
385 if (ftrace_enabled)
386 update_ftrace_function();
387
388 ops->func = ops->saved_func;
389
390 return 0;
391}
392
393static void ftrace_update_pid_func(void)
394{
395 struct ftrace_ops *op;
396
397 /* Only do something if we are tracing something */
398 if (ftrace_trace_function == ftrace_stub)
399 return;
400
401 do_for_each_ftrace_op(op, ftrace_ops_list) {
402 if (op->flags & FTRACE_OPS_FL_PID) {
403 op->func = ftrace_pids_enabled(op) ?
404 ftrace_pid_func : op->saved_func;
405 ftrace_update_trampoline(op);
406 }
407 } while_for_each_ftrace_op(op);
408
409 update_ftrace_function();
410}
411
412#ifdef CONFIG_FUNCTION_PROFILER
413struct ftrace_profile {
414 struct hlist_node node;
415 unsigned long ip;
416 unsigned long counter;
417#ifdef CONFIG_FUNCTION_GRAPH_TRACER
418 unsigned long long time;
419 unsigned long long time_squared;
420#endif
421};
422
423struct ftrace_profile_page {
424 struct ftrace_profile_page *next;
425 unsigned long index;
426 struct ftrace_profile records[];
427};
428
429struct ftrace_profile_stat {
430 atomic_t disabled;
431 struct hlist_head *hash;
432 struct ftrace_profile_page *pages;
433 struct ftrace_profile_page *start;
434 struct tracer_stat stat;
435};
436
437#define PROFILE_RECORDS_SIZE \
438 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
439
440#define PROFILES_PER_PAGE \
441 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
442
443static int ftrace_profile_enabled __read_mostly;
444
445/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
446static DEFINE_MUTEX(ftrace_profile_lock);
447
448static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
449
450#define FTRACE_PROFILE_HASH_BITS 10
451#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
452
453static void *
454function_stat_next(void *v, int idx)
455{
456 struct ftrace_profile *rec = v;
457 struct ftrace_profile_page *pg;
458
459 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
460
461 again:
462 if (idx != 0)
463 rec++;
464
465 if ((void *)rec >= (void *)&pg->records[pg->index]) {
466 pg = pg->next;
467 if (!pg)
468 return NULL;
469 rec = &pg->records[0];
470 if (!rec->counter)
471 goto again;
472 }
473
474 return rec;
475}
476
477static void *function_stat_start(struct tracer_stat *trace)
478{
479 struct ftrace_profile_stat *stat =
480 container_of(trace, struct ftrace_profile_stat, stat);
481
482 if (!stat || !stat->start)
483 return NULL;
484
485 return function_stat_next(&stat->start->records[0], 0);
486}
487
488#ifdef CONFIG_FUNCTION_GRAPH_TRACER
489/* function graph compares on total time */
490static int function_stat_cmp(const void *p1, const void *p2)
491{
492 const struct ftrace_profile *a = p1;
493 const struct ftrace_profile *b = p2;
494
495 if (a->time < b->time)
496 return -1;
497 if (a->time > b->time)
498 return 1;
499 else
500 return 0;
501}
502#else
503/* not function graph compares against hits */
504static int function_stat_cmp(const void *p1, const void *p2)
505{
506 const struct ftrace_profile *a = p1;
507 const struct ftrace_profile *b = p2;
508
509 if (a->counter < b->counter)
510 return -1;
511 if (a->counter > b->counter)
512 return 1;
513 else
514 return 0;
515}
516#endif
517
518static int function_stat_headers(struct seq_file *m)
519{
520#ifdef CONFIG_FUNCTION_GRAPH_TRACER
521 seq_puts(m, " Function "
522 "Hit Time Avg s^2\n"
523 " -------- "
524 "--- ---- --- ---\n");
525#else
526 seq_puts(m, " Function Hit\n"
527 " -------- ---\n");
528#endif
529 return 0;
530}
531
532static int function_stat_show(struct seq_file *m, void *v)
533{
534 struct ftrace_profile *rec = v;
535 char str[KSYM_SYMBOL_LEN];
536 int ret = 0;
537#ifdef CONFIG_FUNCTION_GRAPH_TRACER
538 static struct trace_seq s;
539 unsigned long long avg;
540 unsigned long long stddev;
541#endif
542 mutex_lock(&ftrace_profile_lock);
543
544 /* we raced with function_profile_reset() */
545 if (unlikely(rec->counter == 0)) {
546 ret = -EBUSY;
547 goto out;
548 }
549
550#ifdef CONFIG_FUNCTION_GRAPH_TRACER
551 avg = div64_ul(rec->time, rec->counter);
552 if (tracing_thresh && (avg < tracing_thresh))
553 goto out;
554#endif
555
556 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
557 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
558
559#ifdef CONFIG_FUNCTION_GRAPH_TRACER
560 seq_puts(m, " ");
561
562 /* Sample standard deviation (s^2) */
563 if (rec->counter <= 1)
564 stddev = 0;
565 else {
566 /*
567 * Apply Welford's method:
568 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
569 */
570 stddev = rec->counter * rec->time_squared -
571 rec->time * rec->time;
572
573 /*
574 * Divide only 1000 for ns^2 -> us^2 conversion.
575 * trace_print_graph_duration will divide 1000 again.
576 */
577 stddev = div64_ul(stddev,
578 rec->counter * (rec->counter - 1) * 1000);
579 }
580
581 trace_seq_init(&s);
582 trace_print_graph_duration(rec->time, &s);
583 trace_seq_puts(&s, " ");
584 trace_print_graph_duration(avg, &s);
585 trace_seq_puts(&s, " ");
586 trace_print_graph_duration(stddev, &s);
587 trace_print_seq(m, &s);
588#endif
589 seq_putc(m, '\n');
590out:
591 mutex_unlock(&ftrace_profile_lock);
592
593 return ret;
594}
595
596static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
597{
598 struct ftrace_profile_page *pg;
599
600 pg = stat->pages = stat->start;
601
602 while (pg) {
603 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
604 pg->index = 0;
605 pg = pg->next;
606 }
607
608 memset(stat->hash, 0,
609 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
610}
611
612static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
613{
614 struct ftrace_profile_page *pg;
615 int functions;
616 int pages;
617 int i;
618
619 /* If we already allocated, do nothing */
620 if (stat->pages)
621 return 0;
622
623 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
624 if (!stat->pages)
625 return -ENOMEM;
626
627#ifdef CONFIG_DYNAMIC_FTRACE
628 functions = ftrace_update_tot_cnt;
629#else
630 /*
631 * We do not know the number of functions that exist because
632 * dynamic tracing is what counts them. With past experience
633 * we have around 20K functions. That should be more than enough.
634 * It is highly unlikely we will execute every function in
635 * the kernel.
636 */
637 functions = 20000;
638#endif
639
640 pg = stat->start = stat->pages;
641
642 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
643
644 for (i = 1; i < pages; i++) {
645 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
646 if (!pg->next)
647 goto out_free;
648 pg = pg->next;
649 }
650
651 return 0;
652
653 out_free:
654 pg = stat->start;
655 while (pg) {
656 unsigned long tmp = (unsigned long)pg;
657
658 pg = pg->next;
659 free_page(tmp);
660 }
661
662 stat->pages = NULL;
663 stat->start = NULL;
664
665 return -ENOMEM;
666}
667
668static int ftrace_profile_init_cpu(int cpu)
669{
670 struct ftrace_profile_stat *stat;
671 int size;
672
673 stat = &per_cpu(ftrace_profile_stats, cpu);
674
675 if (stat->hash) {
676 /* If the profile is already created, simply reset it */
677 ftrace_profile_reset(stat);
678 return 0;
679 }
680
681 /*
682 * We are profiling all functions, but usually only a few thousand
683 * functions are hit. We'll make a hash of 1024 items.
684 */
685 size = FTRACE_PROFILE_HASH_SIZE;
686
687 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
688
689 if (!stat->hash)
690 return -ENOMEM;
691
692 /* Preallocate the function profiling pages */
693 if (ftrace_profile_pages_init(stat) < 0) {
694 kfree(stat->hash);
695 stat->hash = NULL;
696 return -ENOMEM;
697 }
698
699 return 0;
700}
701
702static int ftrace_profile_init(void)
703{
704 int cpu;
705 int ret = 0;
706
707 for_each_possible_cpu(cpu) {
708 ret = ftrace_profile_init_cpu(cpu);
709 if (ret)
710 break;
711 }
712
713 return ret;
714}
715
716/* interrupts must be disabled */
717static struct ftrace_profile *
718ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
719{
720 struct ftrace_profile *rec;
721 struct hlist_head *hhd;
722 unsigned long key;
723
724 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
725 hhd = &stat->hash[key];
726
727 if (hlist_empty(hhd))
728 return NULL;
729
730 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
731 if (rec->ip == ip)
732 return rec;
733 }
734
735 return NULL;
736}
737
738static void ftrace_add_profile(struct ftrace_profile_stat *stat,
739 struct ftrace_profile *rec)
740{
741 unsigned long key;
742
743 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
744 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
745}
746
747/*
748 * The memory is already allocated, this simply finds a new record to use.
749 */
750static struct ftrace_profile *
751ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
752{
753 struct ftrace_profile *rec = NULL;
754
755 /* prevent recursion (from NMIs) */
756 if (atomic_inc_return(&stat->disabled) != 1)
757 goto out;
758
759 /*
760 * Try to find the function again since an NMI
761 * could have added it
762 */
763 rec = ftrace_find_profiled_func(stat, ip);
764 if (rec)
765 goto out;
766
767 if (stat->pages->index == PROFILES_PER_PAGE) {
768 if (!stat->pages->next)
769 goto out;
770 stat->pages = stat->pages->next;
771 }
772
773 rec = &stat->pages->records[stat->pages->index++];
774 rec->ip = ip;
775 ftrace_add_profile(stat, rec);
776
777 out:
778 atomic_dec(&stat->disabled);
779
780 return rec;
781}
782
783static void
784function_profile_call(unsigned long ip, unsigned long parent_ip,
785 struct ftrace_ops *ops, struct ftrace_regs *fregs)
786{
787 struct ftrace_profile_stat *stat;
788 struct ftrace_profile *rec;
789 unsigned long flags;
790
791 if (!ftrace_profile_enabled)
792 return;
793
794 local_irq_save(flags);
795
796 stat = this_cpu_ptr(&ftrace_profile_stats);
797 if (!stat->hash || !ftrace_profile_enabled)
798 goto out;
799
800 rec = ftrace_find_profiled_func(stat, ip);
801 if (!rec) {
802 rec = ftrace_profile_alloc(stat, ip);
803 if (!rec)
804 goto out;
805 }
806
807 rec->counter++;
808 out:
809 local_irq_restore(flags);
810}
811
812#ifdef CONFIG_FUNCTION_GRAPH_TRACER
813static bool fgraph_graph_time = true;
814
815void ftrace_graph_graph_time_control(bool enable)
816{
817 fgraph_graph_time = enable;
818}
819
820static int profile_graph_entry(struct ftrace_graph_ent *trace)
821{
822 struct ftrace_ret_stack *ret_stack;
823
824 function_profile_call(trace->func, 0, NULL, NULL);
825
826 /* If function graph is shutting down, ret_stack can be NULL */
827 if (!current->ret_stack)
828 return 0;
829
830 ret_stack = ftrace_graph_get_ret_stack(current, 0);
831 if (ret_stack)
832 ret_stack->subtime = 0;
833
834 return 1;
835}
836
837static void profile_graph_return(struct ftrace_graph_ret *trace)
838{
839 struct ftrace_ret_stack *ret_stack;
840 struct ftrace_profile_stat *stat;
841 unsigned long long calltime;
842 struct ftrace_profile *rec;
843 unsigned long flags;
844
845 local_irq_save(flags);
846 stat = this_cpu_ptr(&ftrace_profile_stats);
847 if (!stat->hash || !ftrace_profile_enabled)
848 goto out;
849
850 /* If the calltime was zero'd ignore it */
851 if (!trace->calltime)
852 goto out;
853
854 calltime = trace->rettime - trace->calltime;
855
856 if (!fgraph_graph_time) {
857
858 /* Append this call time to the parent time to subtract */
859 ret_stack = ftrace_graph_get_ret_stack(current, 1);
860 if (ret_stack)
861 ret_stack->subtime += calltime;
862
863 ret_stack = ftrace_graph_get_ret_stack(current, 0);
864 if (ret_stack && ret_stack->subtime < calltime)
865 calltime -= ret_stack->subtime;
866 else
867 calltime = 0;
868 }
869
870 rec = ftrace_find_profiled_func(stat, trace->func);
871 if (rec) {
872 rec->time += calltime;
873 rec->time_squared += calltime * calltime;
874 }
875
876 out:
877 local_irq_restore(flags);
878}
879
880static struct fgraph_ops fprofiler_ops = {
881 .entryfunc = &profile_graph_entry,
882 .retfunc = &profile_graph_return,
883};
884
885static int register_ftrace_profiler(void)
886{
887 return register_ftrace_graph(&fprofiler_ops);
888}
889
890static void unregister_ftrace_profiler(void)
891{
892 unregister_ftrace_graph(&fprofiler_ops);
893}
894#else
895static struct ftrace_ops ftrace_profile_ops __read_mostly = {
896 .func = function_profile_call,
897 .flags = FTRACE_OPS_FL_INITIALIZED,
898 INIT_OPS_HASH(ftrace_profile_ops)
899};
900
901static int register_ftrace_profiler(void)
902{
903 return register_ftrace_function(&ftrace_profile_ops);
904}
905
906static void unregister_ftrace_profiler(void)
907{
908 unregister_ftrace_function(&ftrace_profile_ops);
909}
910#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
911
912static ssize_t
913ftrace_profile_write(struct file *filp, const char __user *ubuf,
914 size_t cnt, loff_t *ppos)
915{
916 unsigned long val;
917 int ret;
918
919 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
920 if (ret)
921 return ret;
922
923 val = !!val;
924
925 mutex_lock(&ftrace_profile_lock);
926 if (ftrace_profile_enabled ^ val) {
927 if (val) {
928 ret = ftrace_profile_init();
929 if (ret < 0) {
930 cnt = ret;
931 goto out;
932 }
933
934 ret = register_ftrace_profiler();
935 if (ret < 0) {
936 cnt = ret;
937 goto out;
938 }
939 ftrace_profile_enabled = 1;
940 } else {
941 ftrace_profile_enabled = 0;
942 /*
943 * unregister_ftrace_profiler calls stop_machine
944 * so this acts like an synchronize_rcu.
945 */
946 unregister_ftrace_profiler();
947 }
948 }
949 out:
950 mutex_unlock(&ftrace_profile_lock);
951
952 *ppos += cnt;
953
954 return cnt;
955}
956
957static ssize_t
958ftrace_profile_read(struct file *filp, char __user *ubuf,
959 size_t cnt, loff_t *ppos)
960{
961 char buf[64]; /* big enough to hold a number */
962 int r;
963
964 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
965 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
966}
967
968static const struct file_operations ftrace_profile_fops = {
969 .open = tracing_open_generic,
970 .read = ftrace_profile_read,
971 .write = ftrace_profile_write,
972 .llseek = default_llseek,
973};
974
975/* used to initialize the real stat files */
976static struct tracer_stat function_stats __initdata = {
977 .name = "functions",
978 .stat_start = function_stat_start,
979 .stat_next = function_stat_next,
980 .stat_cmp = function_stat_cmp,
981 .stat_headers = function_stat_headers,
982 .stat_show = function_stat_show
983};
984
985static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
986{
987 struct ftrace_profile_stat *stat;
988 char *name;
989 int ret;
990 int cpu;
991
992 for_each_possible_cpu(cpu) {
993 stat = &per_cpu(ftrace_profile_stats, cpu);
994
995 name = kasprintf(GFP_KERNEL, "function%d", cpu);
996 if (!name) {
997 /*
998 * The files created are permanent, if something happens
999 * we still do not free memory.
1000 */
1001 WARN(1,
1002 "Could not allocate stat file for cpu %d\n",
1003 cpu);
1004 return;
1005 }
1006 stat->stat = function_stats;
1007 stat->stat.name = name;
1008 ret = register_stat_tracer(&stat->stat);
1009 if (ret) {
1010 WARN(1,
1011 "Could not register function stat for cpu %d\n",
1012 cpu);
1013 kfree(name);
1014 return;
1015 }
1016 }
1017
1018 trace_create_file("function_profile_enabled",
1019 TRACE_MODE_WRITE, d_tracer, NULL,
1020 &ftrace_profile_fops);
1021}
1022
1023#else /* CONFIG_FUNCTION_PROFILER */
1024static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1025{
1026}
1027#endif /* CONFIG_FUNCTION_PROFILER */
1028
1029#ifdef CONFIG_DYNAMIC_FTRACE
1030
1031static struct ftrace_ops *removed_ops;
1032
1033/*
1034 * Set when doing a global update, like enabling all recs or disabling them.
1035 * It is not set when just updating a single ftrace_ops.
1036 */
1037static bool update_all_ops;
1038
1039#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1040# error Dynamic ftrace depends on MCOUNT_RECORD
1041#endif
1042
1043struct ftrace_func_probe {
1044 struct ftrace_probe_ops *probe_ops;
1045 struct ftrace_ops ops;
1046 struct trace_array *tr;
1047 struct list_head list;
1048 void *data;
1049 int ref;
1050};
1051
1052/*
1053 * We make these constant because no one should touch them,
1054 * but they are used as the default "empty hash", to avoid allocating
1055 * it all the time. These are in a read only section such that if
1056 * anyone does try to modify it, it will cause an exception.
1057 */
1058static const struct hlist_head empty_buckets[1];
1059static const struct ftrace_hash empty_hash = {
1060 .buckets = (struct hlist_head *)empty_buckets,
1061};
1062#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1063
1064struct ftrace_ops global_ops = {
1065 .func = ftrace_stub,
1066 .local_hash.notrace_hash = EMPTY_HASH,
1067 .local_hash.filter_hash = EMPTY_HASH,
1068 INIT_OPS_HASH(global_ops)
1069 .flags = FTRACE_OPS_FL_INITIALIZED |
1070 FTRACE_OPS_FL_PID,
1071};
1072
1073/*
1074 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1075 */
1076struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1077{
1078 struct ftrace_ops *op = NULL;
1079
1080 /*
1081 * Some of the ops may be dynamically allocated,
1082 * they are freed after a synchronize_rcu().
1083 */
1084 preempt_disable_notrace();
1085
1086 do_for_each_ftrace_op(op, ftrace_ops_list) {
1087 /*
1088 * This is to check for dynamically allocated trampolines.
1089 * Trampolines that are in kernel text will have
1090 * core_kernel_text() return true.
1091 */
1092 if (op->trampoline && op->trampoline_size)
1093 if (addr >= op->trampoline &&
1094 addr < op->trampoline + op->trampoline_size) {
1095 preempt_enable_notrace();
1096 return op;
1097 }
1098 } while_for_each_ftrace_op(op);
1099 preempt_enable_notrace();
1100
1101 return NULL;
1102}
1103
1104/*
1105 * This is used by __kernel_text_address() to return true if the
1106 * address is on a dynamically allocated trampoline that would
1107 * not return true for either core_kernel_text() or
1108 * is_module_text_address().
1109 */
1110bool is_ftrace_trampoline(unsigned long addr)
1111{
1112 return ftrace_ops_trampoline(addr) != NULL;
1113}
1114
1115struct ftrace_page {
1116 struct ftrace_page *next;
1117 struct dyn_ftrace *records;
1118 int index;
1119 int order;
1120};
1121
1122#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1123#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1124
1125static struct ftrace_page *ftrace_pages_start;
1126static struct ftrace_page *ftrace_pages;
1127
1128static __always_inline unsigned long
1129ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1130{
1131 if (hash->size_bits > 0)
1132 return hash_long(ip, hash->size_bits);
1133
1134 return 0;
1135}
1136
1137/* Only use this function if ftrace_hash_empty() has already been tested */
1138static __always_inline struct ftrace_func_entry *
1139__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1140{
1141 unsigned long key;
1142 struct ftrace_func_entry *entry;
1143 struct hlist_head *hhd;
1144
1145 key = ftrace_hash_key(hash, ip);
1146 hhd = &hash->buckets[key];
1147
1148 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1149 if (entry->ip == ip)
1150 return entry;
1151 }
1152 return NULL;
1153}
1154
1155/**
1156 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1157 * @hash: The hash to look at
1158 * @ip: The instruction pointer to test
1159 *
1160 * Search a given @hash to see if a given instruction pointer (@ip)
1161 * exists in it.
1162 *
1163 * Returns the entry that holds the @ip if found. NULL otherwise.
1164 */
1165struct ftrace_func_entry *
1166ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1167{
1168 if (ftrace_hash_empty(hash))
1169 return NULL;
1170
1171 return __ftrace_lookup_ip(hash, ip);
1172}
1173
1174static void __add_hash_entry(struct ftrace_hash *hash,
1175 struct ftrace_func_entry *entry)
1176{
1177 struct hlist_head *hhd;
1178 unsigned long key;
1179
1180 key = ftrace_hash_key(hash, entry->ip);
1181 hhd = &hash->buckets[key];
1182 hlist_add_head(&entry->hlist, hhd);
1183 hash->count++;
1184}
1185
1186static struct ftrace_func_entry *
1187add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1188{
1189 struct ftrace_func_entry *entry;
1190
1191 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1192 if (!entry)
1193 return NULL;
1194
1195 entry->ip = ip;
1196 __add_hash_entry(hash, entry);
1197
1198 return entry;
1199}
1200
1201static void
1202free_hash_entry(struct ftrace_hash *hash,
1203 struct ftrace_func_entry *entry)
1204{
1205 hlist_del(&entry->hlist);
1206 kfree(entry);
1207 hash->count--;
1208}
1209
1210static void
1211remove_hash_entry(struct ftrace_hash *hash,
1212 struct ftrace_func_entry *entry)
1213{
1214 hlist_del_rcu(&entry->hlist);
1215 hash->count--;
1216}
1217
1218static void ftrace_hash_clear(struct ftrace_hash *hash)
1219{
1220 struct hlist_head *hhd;
1221 struct hlist_node *tn;
1222 struct ftrace_func_entry *entry;
1223 int size = 1 << hash->size_bits;
1224 int i;
1225
1226 if (!hash->count)
1227 return;
1228
1229 for (i = 0; i < size; i++) {
1230 hhd = &hash->buckets[i];
1231 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1232 free_hash_entry(hash, entry);
1233 }
1234 FTRACE_WARN_ON(hash->count);
1235}
1236
1237static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1238{
1239 list_del(&ftrace_mod->list);
1240 kfree(ftrace_mod->module);
1241 kfree(ftrace_mod->func);
1242 kfree(ftrace_mod);
1243}
1244
1245static void clear_ftrace_mod_list(struct list_head *head)
1246{
1247 struct ftrace_mod_load *p, *n;
1248
1249 /* stack tracer isn't supported yet */
1250 if (!head)
1251 return;
1252
1253 mutex_lock(&ftrace_lock);
1254 list_for_each_entry_safe(p, n, head, list)
1255 free_ftrace_mod(p);
1256 mutex_unlock(&ftrace_lock);
1257}
1258
1259static void free_ftrace_hash(struct ftrace_hash *hash)
1260{
1261 if (!hash || hash == EMPTY_HASH)
1262 return;
1263 ftrace_hash_clear(hash);
1264 kfree(hash->buckets);
1265 kfree(hash);
1266}
1267
1268static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1269{
1270 struct ftrace_hash *hash;
1271
1272 hash = container_of(rcu, struct ftrace_hash, rcu);
1273 free_ftrace_hash(hash);
1274}
1275
1276static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1277{
1278 if (!hash || hash == EMPTY_HASH)
1279 return;
1280 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1281}
1282
1283/**
1284 * ftrace_free_filter - remove all filters for an ftrace_ops
1285 * @ops - the ops to remove the filters from
1286 */
1287void ftrace_free_filter(struct ftrace_ops *ops)
1288{
1289 ftrace_ops_init(ops);
1290 free_ftrace_hash(ops->func_hash->filter_hash);
1291 free_ftrace_hash(ops->func_hash->notrace_hash);
1292}
1293EXPORT_SYMBOL_GPL(ftrace_free_filter);
1294
1295static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1296{
1297 struct ftrace_hash *hash;
1298 int size;
1299
1300 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1301 if (!hash)
1302 return NULL;
1303
1304 size = 1 << size_bits;
1305 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1306
1307 if (!hash->buckets) {
1308 kfree(hash);
1309 return NULL;
1310 }
1311
1312 hash->size_bits = size_bits;
1313
1314 return hash;
1315}
1316
1317
1318static int ftrace_add_mod(struct trace_array *tr,
1319 const char *func, const char *module,
1320 int enable)
1321{
1322 struct ftrace_mod_load *ftrace_mod;
1323 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1324
1325 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1326 if (!ftrace_mod)
1327 return -ENOMEM;
1328
1329 INIT_LIST_HEAD(&ftrace_mod->list);
1330 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1331 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1332 ftrace_mod->enable = enable;
1333
1334 if (!ftrace_mod->func || !ftrace_mod->module)
1335 goto out_free;
1336
1337 list_add(&ftrace_mod->list, mod_head);
1338
1339 return 0;
1340
1341 out_free:
1342 free_ftrace_mod(ftrace_mod);
1343
1344 return -ENOMEM;
1345}
1346
1347static struct ftrace_hash *
1348alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1349{
1350 struct ftrace_func_entry *entry;
1351 struct ftrace_hash *new_hash;
1352 int size;
1353 int i;
1354
1355 new_hash = alloc_ftrace_hash(size_bits);
1356 if (!new_hash)
1357 return NULL;
1358
1359 if (hash)
1360 new_hash->flags = hash->flags;
1361
1362 /* Empty hash? */
1363 if (ftrace_hash_empty(hash))
1364 return new_hash;
1365
1366 size = 1 << hash->size_bits;
1367 for (i = 0; i < size; i++) {
1368 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1369 if (add_hash_entry(new_hash, entry->ip) == NULL)
1370 goto free_hash;
1371 }
1372 }
1373
1374 FTRACE_WARN_ON(new_hash->count != hash->count);
1375
1376 return new_hash;
1377
1378 free_hash:
1379 free_ftrace_hash(new_hash);
1380 return NULL;
1381}
1382
1383static void
1384ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1385static void
1386ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1387
1388static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1389 struct ftrace_hash *new_hash);
1390
1391static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1392{
1393 struct ftrace_func_entry *entry;
1394 struct ftrace_hash *new_hash;
1395 struct hlist_head *hhd;
1396 struct hlist_node *tn;
1397 int bits = 0;
1398 int i;
1399
1400 /*
1401 * Use around half the size (max bit of it), but
1402 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1403 */
1404 bits = fls(size / 2);
1405
1406 /* Don't allocate too much */
1407 if (bits > FTRACE_HASH_MAX_BITS)
1408 bits = FTRACE_HASH_MAX_BITS;
1409
1410 new_hash = alloc_ftrace_hash(bits);
1411 if (!new_hash)
1412 return NULL;
1413
1414 new_hash->flags = src->flags;
1415
1416 size = 1 << src->size_bits;
1417 for (i = 0; i < size; i++) {
1418 hhd = &src->buckets[i];
1419 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1420 remove_hash_entry(src, entry);
1421 __add_hash_entry(new_hash, entry);
1422 }
1423 }
1424 return new_hash;
1425}
1426
1427static struct ftrace_hash *
1428__ftrace_hash_move(struct ftrace_hash *src)
1429{
1430 int size = src->count;
1431
1432 /*
1433 * If the new source is empty, just return the empty_hash.
1434 */
1435 if (ftrace_hash_empty(src))
1436 return EMPTY_HASH;
1437
1438 return dup_hash(src, size);
1439}
1440
1441static int
1442ftrace_hash_move(struct ftrace_ops *ops, int enable,
1443 struct ftrace_hash **dst, struct ftrace_hash *src)
1444{
1445 struct ftrace_hash *new_hash;
1446 int ret;
1447
1448 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1449 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1450 return -EINVAL;
1451
1452 new_hash = __ftrace_hash_move(src);
1453 if (!new_hash)
1454 return -ENOMEM;
1455
1456 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1457 if (enable) {
1458 /* IPMODIFY should be updated only when filter_hash updating */
1459 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1460 if (ret < 0) {
1461 free_ftrace_hash(new_hash);
1462 return ret;
1463 }
1464 }
1465
1466 /*
1467 * Remove the current set, update the hash and add
1468 * them back.
1469 */
1470 ftrace_hash_rec_disable_modify(ops, enable);
1471
1472 rcu_assign_pointer(*dst, new_hash);
1473
1474 ftrace_hash_rec_enable_modify(ops, enable);
1475
1476 return 0;
1477}
1478
1479static bool hash_contains_ip(unsigned long ip,
1480 struct ftrace_ops_hash *hash)
1481{
1482 /*
1483 * The function record is a match if it exists in the filter
1484 * hash and not in the notrace hash. Note, an empty hash is
1485 * considered a match for the filter hash, but an empty
1486 * notrace hash is considered not in the notrace hash.
1487 */
1488 return (ftrace_hash_empty(hash->filter_hash) ||
1489 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1490 (ftrace_hash_empty(hash->notrace_hash) ||
1491 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1492}
1493
1494/*
1495 * Test the hashes for this ops to see if we want to call
1496 * the ops->func or not.
1497 *
1498 * It's a match if the ip is in the ops->filter_hash or
1499 * the filter_hash does not exist or is empty,
1500 * AND
1501 * the ip is not in the ops->notrace_hash.
1502 *
1503 * This needs to be called with preemption disabled as
1504 * the hashes are freed with call_rcu().
1505 */
1506int
1507ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1508{
1509 struct ftrace_ops_hash hash;
1510 int ret;
1511
1512#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1513 /*
1514 * There's a small race when adding ops that the ftrace handler
1515 * that wants regs, may be called without them. We can not
1516 * allow that handler to be called if regs is NULL.
1517 */
1518 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1519 return 0;
1520#endif
1521
1522 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1523 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1524
1525 if (hash_contains_ip(ip, &hash))
1526 ret = 1;
1527 else
1528 ret = 0;
1529
1530 return ret;
1531}
1532
1533/*
1534 * This is a double for. Do not use 'break' to break out of the loop,
1535 * you must use a goto.
1536 */
1537#define do_for_each_ftrace_rec(pg, rec) \
1538 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1539 int _____i; \
1540 for (_____i = 0; _____i < pg->index; _____i++) { \
1541 rec = &pg->records[_____i];
1542
1543#define while_for_each_ftrace_rec() \
1544 } \
1545 }
1546
1547
1548static int ftrace_cmp_recs(const void *a, const void *b)
1549{
1550 const struct dyn_ftrace *key = a;
1551 const struct dyn_ftrace *rec = b;
1552
1553 if (key->flags < rec->ip)
1554 return -1;
1555 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1556 return 1;
1557 return 0;
1558}
1559
1560static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1561{
1562 struct ftrace_page *pg;
1563 struct dyn_ftrace *rec = NULL;
1564 struct dyn_ftrace key;
1565
1566 key.ip = start;
1567 key.flags = end; /* overload flags, as it is unsigned long */
1568
1569 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1570 if (pg->index == 0 ||
1571 end < pg->records[0].ip ||
1572 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1573 continue;
1574 rec = bsearch(&key, pg->records, pg->index,
1575 sizeof(struct dyn_ftrace),
1576 ftrace_cmp_recs);
1577 if (rec)
1578 break;
1579 }
1580 return rec;
1581}
1582
1583/**
1584 * ftrace_location_range - return the first address of a traced location
1585 * if it touches the given ip range
1586 * @start: start of range to search.
1587 * @end: end of range to search (inclusive). @end points to the last byte
1588 * to check.
1589 *
1590 * Returns rec->ip if the related ftrace location is a least partly within
1591 * the given address range. That is, the first address of the instruction
1592 * that is either a NOP or call to the function tracer. It checks the ftrace
1593 * internal tables to determine if the address belongs or not.
1594 */
1595unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1596{
1597 struct dyn_ftrace *rec;
1598
1599 rec = lookup_rec(start, end);
1600 if (rec)
1601 return rec->ip;
1602
1603 return 0;
1604}
1605
1606/**
1607 * ftrace_location - return the ftrace location
1608 * @ip: the instruction pointer to check
1609 *
1610 * If @ip matches the ftrace location, return @ip.
1611 * If @ip matches sym+0, return sym's ftrace location.
1612 * Otherwise, return 0.
1613 */
1614unsigned long ftrace_location(unsigned long ip)
1615{
1616 struct dyn_ftrace *rec;
1617 unsigned long offset;
1618 unsigned long size;
1619
1620 rec = lookup_rec(ip, ip);
1621 if (!rec) {
1622 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1623 goto out;
1624
1625 /* map sym+0 to __fentry__ */
1626 if (!offset)
1627 rec = lookup_rec(ip, ip + size - 1);
1628 }
1629
1630 if (rec)
1631 return rec->ip;
1632
1633out:
1634 return 0;
1635}
1636
1637/**
1638 * ftrace_text_reserved - return true if range contains an ftrace location
1639 * @start: start of range to search
1640 * @end: end of range to search (inclusive). @end points to the last byte to check.
1641 *
1642 * Returns 1 if @start and @end contains a ftrace location.
1643 * That is, the instruction that is either a NOP or call to
1644 * the function tracer. It checks the ftrace internal tables to
1645 * determine if the address belongs or not.
1646 */
1647int ftrace_text_reserved(const void *start, const void *end)
1648{
1649 unsigned long ret;
1650
1651 ret = ftrace_location_range((unsigned long)start,
1652 (unsigned long)end);
1653
1654 return (int)!!ret;
1655}
1656
1657/* Test if ops registered to this rec needs regs */
1658static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1659{
1660 struct ftrace_ops *ops;
1661 bool keep_regs = false;
1662
1663 for (ops = ftrace_ops_list;
1664 ops != &ftrace_list_end; ops = ops->next) {
1665 /* pass rec in as regs to have non-NULL val */
1666 if (ftrace_ops_test(ops, rec->ip, rec)) {
1667 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1668 keep_regs = true;
1669 break;
1670 }
1671 }
1672 }
1673
1674 return keep_regs;
1675}
1676
1677static struct ftrace_ops *
1678ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1679static struct ftrace_ops *
1680ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1681static struct ftrace_ops *
1682ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1683
1684static bool skip_record(struct dyn_ftrace *rec)
1685{
1686 /*
1687 * At boot up, weak functions are set to disable. Function tracing
1688 * can be enabled before they are, and they still need to be disabled now.
1689 * If the record is disabled, still continue if it is marked as already
1690 * enabled (this is needed to keep the accounting working).
1691 */
1692 return rec->flags & FTRACE_FL_DISABLED &&
1693 !(rec->flags & FTRACE_FL_ENABLED);
1694}
1695
1696static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1697 int filter_hash,
1698 bool inc)
1699{
1700 struct ftrace_hash *hash;
1701 struct ftrace_hash *other_hash;
1702 struct ftrace_page *pg;
1703 struct dyn_ftrace *rec;
1704 bool update = false;
1705 int count = 0;
1706 int all = false;
1707
1708 /* Only update if the ops has been registered */
1709 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1710 return false;
1711
1712 /*
1713 * In the filter_hash case:
1714 * If the count is zero, we update all records.
1715 * Otherwise we just update the items in the hash.
1716 *
1717 * In the notrace_hash case:
1718 * We enable the update in the hash.
1719 * As disabling notrace means enabling the tracing,
1720 * and enabling notrace means disabling, the inc variable
1721 * gets inversed.
1722 */
1723 if (filter_hash) {
1724 hash = ops->func_hash->filter_hash;
1725 other_hash = ops->func_hash->notrace_hash;
1726 if (ftrace_hash_empty(hash))
1727 all = true;
1728 } else {
1729 inc = !inc;
1730 hash = ops->func_hash->notrace_hash;
1731 other_hash = ops->func_hash->filter_hash;
1732 /*
1733 * If the notrace hash has no items,
1734 * then there's nothing to do.
1735 */
1736 if (ftrace_hash_empty(hash))
1737 return false;
1738 }
1739
1740 do_for_each_ftrace_rec(pg, rec) {
1741 int in_other_hash = 0;
1742 int in_hash = 0;
1743 int match = 0;
1744
1745 if (skip_record(rec))
1746 continue;
1747
1748 if (all) {
1749 /*
1750 * Only the filter_hash affects all records.
1751 * Update if the record is not in the notrace hash.
1752 */
1753 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1754 match = 1;
1755 } else {
1756 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1757 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1758
1759 /*
1760 * If filter_hash is set, we want to match all functions
1761 * that are in the hash but not in the other hash.
1762 *
1763 * If filter_hash is not set, then we are decrementing.
1764 * That means we match anything that is in the hash
1765 * and also in the other_hash. That is, we need to turn
1766 * off functions in the other hash because they are disabled
1767 * by this hash.
1768 */
1769 if (filter_hash && in_hash && !in_other_hash)
1770 match = 1;
1771 else if (!filter_hash && in_hash &&
1772 (in_other_hash || ftrace_hash_empty(other_hash)))
1773 match = 1;
1774 }
1775 if (!match)
1776 continue;
1777
1778 if (inc) {
1779 rec->flags++;
1780 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1781 return false;
1782
1783 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1784 rec->flags |= FTRACE_FL_DIRECT;
1785
1786 /*
1787 * If there's only a single callback registered to a
1788 * function, and the ops has a trampoline registered
1789 * for it, then we can call it directly.
1790 */
1791 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1792 rec->flags |= FTRACE_FL_TRAMP;
1793 else
1794 /*
1795 * If we are adding another function callback
1796 * to this function, and the previous had a
1797 * custom trampoline in use, then we need to go
1798 * back to the default trampoline.
1799 */
1800 rec->flags &= ~FTRACE_FL_TRAMP;
1801
1802 /*
1803 * If any ops wants regs saved for this function
1804 * then all ops will get saved regs.
1805 */
1806 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1807 rec->flags |= FTRACE_FL_REGS;
1808 } else {
1809 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1810 return false;
1811 rec->flags--;
1812
1813 /*
1814 * Only the internal direct_ops should have the
1815 * DIRECT flag set. Thus, if it is removing a
1816 * function, then that function should no longer
1817 * be direct.
1818 */
1819 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1820 rec->flags &= ~FTRACE_FL_DIRECT;
1821
1822 /*
1823 * If the rec had REGS enabled and the ops that is
1824 * being removed had REGS set, then see if there is
1825 * still any ops for this record that wants regs.
1826 * If not, we can stop recording them.
1827 */
1828 if (ftrace_rec_count(rec) > 0 &&
1829 rec->flags & FTRACE_FL_REGS &&
1830 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1831 if (!test_rec_ops_needs_regs(rec))
1832 rec->flags &= ~FTRACE_FL_REGS;
1833 }
1834
1835 /*
1836 * The TRAMP needs to be set only if rec count
1837 * is decremented to one, and the ops that is
1838 * left has a trampoline. As TRAMP can only be
1839 * enabled if there is only a single ops attached
1840 * to it.
1841 */
1842 if (ftrace_rec_count(rec) == 1 &&
1843 ftrace_find_tramp_ops_any_other(rec, ops))
1844 rec->flags |= FTRACE_FL_TRAMP;
1845 else
1846 rec->flags &= ~FTRACE_FL_TRAMP;
1847
1848 /*
1849 * flags will be cleared in ftrace_check_record()
1850 * if rec count is zero.
1851 */
1852 }
1853
1854 /*
1855 * If the rec has a single associated ops, and ops->func can be
1856 * called directly, allow the call site to call via the ops.
1857 */
1858 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1859 ftrace_rec_count(rec) == 1 &&
1860 ftrace_ops_get_func(ops) == ops->func)
1861 rec->flags |= FTRACE_FL_CALL_OPS;
1862 else
1863 rec->flags &= ~FTRACE_FL_CALL_OPS;
1864
1865 count++;
1866
1867 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1868 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1869
1870 /* Shortcut, if we handled all records, we are done. */
1871 if (!all && count == hash->count)
1872 return update;
1873 } while_for_each_ftrace_rec();
1874
1875 return update;
1876}
1877
1878static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1879 int filter_hash)
1880{
1881 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1882}
1883
1884static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1885 int filter_hash)
1886{
1887 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1888}
1889
1890static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1891 int filter_hash, int inc)
1892{
1893 struct ftrace_ops *op;
1894
1895 __ftrace_hash_rec_update(ops, filter_hash, inc);
1896
1897 if (ops->func_hash != &global_ops.local_hash)
1898 return;
1899
1900 /*
1901 * If the ops shares the global_ops hash, then we need to update
1902 * all ops that are enabled and use this hash.
1903 */
1904 do_for_each_ftrace_op(op, ftrace_ops_list) {
1905 /* Already done */
1906 if (op == ops)
1907 continue;
1908 if (op->func_hash == &global_ops.local_hash)
1909 __ftrace_hash_rec_update(op, filter_hash, inc);
1910 } while_for_each_ftrace_op(op);
1911}
1912
1913static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1914 int filter_hash)
1915{
1916 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1917}
1918
1919static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1920 int filter_hash)
1921{
1922 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1923}
1924
1925/*
1926 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1927 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1928 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1929 * Note that old_hash and new_hash has below meanings
1930 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1931 * - If the hash is EMPTY_HASH, it hits nothing
1932 * - Anything else hits the recs which match the hash entries.
1933 *
1934 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1935 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1936 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1937 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1938 * the return value to the caller and eventually to the owner of the DIRECT
1939 * ops.
1940 */
1941static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1942 struct ftrace_hash *old_hash,
1943 struct ftrace_hash *new_hash)
1944{
1945 struct ftrace_page *pg;
1946 struct dyn_ftrace *rec, *end = NULL;
1947 int in_old, in_new;
1948 bool is_ipmodify, is_direct;
1949
1950 /* Only update if the ops has been registered */
1951 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1952 return 0;
1953
1954 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1955 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1956
1957 /* neither IPMODIFY nor DIRECT, skip */
1958 if (!is_ipmodify && !is_direct)
1959 return 0;
1960
1961 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1962 return 0;
1963
1964 /*
1965 * Since the IPMODIFY and DIRECT are very address sensitive
1966 * actions, we do not allow ftrace_ops to set all functions to new
1967 * hash.
1968 */
1969 if (!new_hash || !old_hash)
1970 return -EINVAL;
1971
1972 /* Update rec->flags */
1973 do_for_each_ftrace_rec(pg, rec) {
1974
1975 if (rec->flags & FTRACE_FL_DISABLED)
1976 continue;
1977
1978 /* We need to update only differences of filter_hash */
1979 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1980 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1981 if (in_old == in_new)
1982 continue;
1983
1984 if (in_new) {
1985 if (rec->flags & FTRACE_FL_IPMODIFY) {
1986 int ret;
1987
1988 /* Cannot have two ipmodify on same rec */
1989 if (is_ipmodify)
1990 goto rollback;
1991
1992 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1993
1994 /*
1995 * Another ops with IPMODIFY is already
1996 * attached. We are now attaching a direct
1997 * ops. Run SHARE_IPMODIFY_SELF, to check
1998 * whether sharing is supported.
1999 */
2000 if (!ops->ops_func)
2001 return -EBUSY;
2002 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2003 if (ret)
2004 return ret;
2005 } else if (is_ipmodify) {
2006 rec->flags |= FTRACE_FL_IPMODIFY;
2007 }
2008 } else if (is_ipmodify) {
2009 rec->flags &= ~FTRACE_FL_IPMODIFY;
2010 }
2011 } while_for_each_ftrace_rec();
2012
2013 return 0;
2014
2015rollback:
2016 end = rec;
2017
2018 /* Roll back what we did above */
2019 do_for_each_ftrace_rec(pg, rec) {
2020
2021 if (rec->flags & FTRACE_FL_DISABLED)
2022 continue;
2023
2024 if (rec == end)
2025 goto err_out;
2026
2027 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2028 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2029 if (in_old == in_new)
2030 continue;
2031
2032 if (in_new)
2033 rec->flags &= ~FTRACE_FL_IPMODIFY;
2034 else
2035 rec->flags |= FTRACE_FL_IPMODIFY;
2036 } while_for_each_ftrace_rec();
2037
2038err_out:
2039 return -EBUSY;
2040}
2041
2042static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2043{
2044 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2045
2046 if (ftrace_hash_empty(hash))
2047 hash = NULL;
2048
2049 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2050}
2051
2052/* Disabling always succeeds */
2053static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2054{
2055 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2056
2057 if (ftrace_hash_empty(hash))
2058 hash = NULL;
2059
2060 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2061}
2062
2063static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2064 struct ftrace_hash *new_hash)
2065{
2066 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2067
2068 if (ftrace_hash_empty(old_hash))
2069 old_hash = NULL;
2070
2071 if (ftrace_hash_empty(new_hash))
2072 new_hash = NULL;
2073
2074 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2075}
2076
2077static void print_ip_ins(const char *fmt, const unsigned char *p)
2078{
2079 char ins[MCOUNT_INSN_SIZE];
2080
2081 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2082 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2083 return;
2084 }
2085
2086 printk(KERN_CONT "%s", fmt);
2087 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2088}
2089
2090enum ftrace_bug_type ftrace_bug_type;
2091const void *ftrace_expected;
2092
2093static void print_bug_type(void)
2094{
2095 switch (ftrace_bug_type) {
2096 case FTRACE_BUG_UNKNOWN:
2097 break;
2098 case FTRACE_BUG_INIT:
2099 pr_info("Initializing ftrace call sites\n");
2100 break;
2101 case FTRACE_BUG_NOP:
2102 pr_info("Setting ftrace call site to NOP\n");
2103 break;
2104 case FTRACE_BUG_CALL:
2105 pr_info("Setting ftrace call site to call ftrace function\n");
2106 break;
2107 case FTRACE_BUG_UPDATE:
2108 pr_info("Updating ftrace call site to call a different ftrace function\n");
2109 break;
2110 }
2111}
2112
2113/**
2114 * ftrace_bug - report and shutdown function tracer
2115 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2116 * @rec: The record that failed
2117 *
2118 * The arch code that enables or disables the function tracing
2119 * can call ftrace_bug() when it has detected a problem in
2120 * modifying the code. @failed should be one of either:
2121 * EFAULT - if the problem happens on reading the @ip address
2122 * EINVAL - if what is read at @ip is not what was expected
2123 * EPERM - if the problem happens on writing to the @ip address
2124 */
2125void ftrace_bug(int failed, struct dyn_ftrace *rec)
2126{
2127 unsigned long ip = rec ? rec->ip : 0;
2128
2129 pr_info("------------[ ftrace bug ]------------\n");
2130
2131 switch (failed) {
2132 case -EFAULT:
2133 pr_info("ftrace faulted on modifying ");
2134 print_ip_sym(KERN_INFO, ip);
2135 break;
2136 case -EINVAL:
2137 pr_info("ftrace failed to modify ");
2138 print_ip_sym(KERN_INFO, ip);
2139 print_ip_ins(" actual: ", (unsigned char *)ip);
2140 pr_cont("\n");
2141 if (ftrace_expected) {
2142 print_ip_ins(" expected: ", ftrace_expected);
2143 pr_cont("\n");
2144 }
2145 break;
2146 case -EPERM:
2147 pr_info("ftrace faulted on writing ");
2148 print_ip_sym(KERN_INFO, ip);
2149 break;
2150 default:
2151 pr_info("ftrace faulted on unknown error ");
2152 print_ip_sym(KERN_INFO, ip);
2153 }
2154 print_bug_type();
2155 if (rec) {
2156 struct ftrace_ops *ops = NULL;
2157
2158 pr_info("ftrace record flags: %lx\n", rec->flags);
2159 pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2160 rec->flags & FTRACE_FL_REGS ? " R" : " ",
2161 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ");
2162 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2163 ops = ftrace_find_tramp_ops_any(rec);
2164 if (ops) {
2165 do {
2166 pr_cont("\ttramp: %pS (%pS)",
2167 (void *)ops->trampoline,
2168 (void *)ops->func);
2169 ops = ftrace_find_tramp_ops_next(rec, ops);
2170 } while (ops);
2171 } else
2172 pr_cont("\ttramp: ERROR!");
2173
2174 }
2175 ip = ftrace_get_addr_curr(rec);
2176 pr_cont("\n expected tramp: %lx\n", ip);
2177 }
2178
2179 FTRACE_WARN_ON_ONCE(1);
2180}
2181
2182static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2183{
2184 unsigned long flag = 0UL;
2185
2186 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2187
2188 if (skip_record(rec))
2189 return FTRACE_UPDATE_IGNORE;
2190
2191 /*
2192 * If we are updating calls:
2193 *
2194 * If the record has a ref count, then we need to enable it
2195 * because someone is using it.
2196 *
2197 * Otherwise we make sure its disabled.
2198 *
2199 * If we are disabling calls, then disable all records that
2200 * are enabled.
2201 */
2202 if (enable && ftrace_rec_count(rec))
2203 flag = FTRACE_FL_ENABLED;
2204
2205 /*
2206 * If enabling and the REGS flag does not match the REGS_EN, or
2207 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2208 * this record. Set flags to fail the compare against ENABLED.
2209 * Same for direct calls.
2210 */
2211 if (flag) {
2212 if (!(rec->flags & FTRACE_FL_REGS) !=
2213 !(rec->flags & FTRACE_FL_REGS_EN))
2214 flag |= FTRACE_FL_REGS;
2215
2216 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2217 !(rec->flags & FTRACE_FL_TRAMP_EN))
2218 flag |= FTRACE_FL_TRAMP;
2219
2220 /*
2221 * Direct calls are special, as count matters.
2222 * We must test the record for direct, if the
2223 * DIRECT and DIRECT_EN do not match, but only
2224 * if the count is 1. That's because, if the
2225 * count is something other than one, we do not
2226 * want the direct enabled (it will be done via the
2227 * direct helper). But if DIRECT_EN is set, and
2228 * the count is not one, we need to clear it.
2229 *
2230 */
2231 if (ftrace_rec_count(rec) == 1) {
2232 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2233 !(rec->flags & FTRACE_FL_DIRECT_EN))
2234 flag |= FTRACE_FL_DIRECT;
2235 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2236 flag |= FTRACE_FL_DIRECT;
2237 }
2238
2239 /*
2240 * Ops calls are special, as count matters.
2241 * As with direct calls, they must only be enabled when count
2242 * is one, otherwise they'll be handled via the list ops.
2243 */
2244 if (ftrace_rec_count(rec) == 1) {
2245 if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2246 !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2247 flag |= FTRACE_FL_CALL_OPS;
2248 } else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2249 flag |= FTRACE_FL_CALL_OPS;
2250 }
2251 }
2252
2253 /* If the state of this record hasn't changed, then do nothing */
2254 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2255 return FTRACE_UPDATE_IGNORE;
2256
2257 if (flag) {
2258 /* Save off if rec is being enabled (for return value) */
2259 flag ^= rec->flags & FTRACE_FL_ENABLED;
2260
2261 if (update) {
2262 rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2263 if (flag & FTRACE_FL_REGS) {
2264 if (rec->flags & FTRACE_FL_REGS)
2265 rec->flags |= FTRACE_FL_REGS_EN;
2266 else
2267 rec->flags &= ~FTRACE_FL_REGS_EN;
2268 }
2269 if (flag & FTRACE_FL_TRAMP) {
2270 if (rec->flags & FTRACE_FL_TRAMP)
2271 rec->flags |= FTRACE_FL_TRAMP_EN;
2272 else
2273 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2274 }
2275
2276 /* Keep track of anything that modifies the function */
2277 if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2278 rec->flags |= FTRACE_FL_MODIFIED;
2279
2280 if (flag & FTRACE_FL_DIRECT) {
2281 /*
2282 * If there's only one user (direct_ops helper)
2283 * then we can call the direct function
2284 * directly (no ftrace trampoline).
2285 */
2286 if (ftrace_rec_count(rec) == 1) {
2287 if (rec->flags & FTRACE_FL_DIRECT)
2288 rec->flags |= FTRACE_FL_DIRECT_EN;
2289 else
2290 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2291 } else {
2292 /*
2293 * Can only call directly if there's
2294 * only one callback to the function.
2295 */
2296 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2297 }
2298 }
2299
2300 if (flag & FTRACE_FL_CALL_OPS) {
2301 if (ftrace_rec_count(rec) == 1) {
2302 if (rec->flags & FTRACE_FL_CALL_OPS)
2303 rec->flags |= FTRACE_FL_CALL_OPS_EN;
2304 else
2305 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2306 } else {
2307 /*
2308 * Can only call directly if there's
2309 * only one set of associated ops.
2310 */
2311 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2312 }
2313 }
2314 }
2315
2316 /*
2317 * If this record is being updated from a nop, then
2318 * return UPDATE_MAKE_CALL.
2319 * Otherwise,
2320 * return UPDATE_MODIFY_CALL to tell the caller to convert
2321 * from the save regs, to a non-save regs function or
2322 * vice versa, or from a trampoline call.
2323 */
2324 if (flag & FTRACE_FL_ENABLED) {
2325 ftrace_bug_type = FTRACE_BUG_CALL;
2326 return FTRACE_UPDATE_MAKE_CALL;
2327 }
2328
2329 ftrace_bug_type = FTRACE_BUG_UPDATE;
2330 return FTRACE_UPDATE_MODIFY_CALL;
2331 }
2332
2333 if (update) {
2334 /* If there's no more users, clear all flags */
2335 if (!ftrace_rec_count(rec))
2336 rec->flags &= FTRACE_NOCLEAR_FLAGS;
2337 else
2338 /*
2339 * Just disable the record, but keep the ops TRAMP
2340 * and REGS states. The _EN flags must be disabled though.
2341 */
2342 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2343 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2344 FTRACE_FL_CALL_OPS_EN);
2345 }
2346
2347 ftrace_bug_type = FTRACE_BUG_NOP;
2348 return FTRACE_UPDATE_MAKE_NOP;
2349}
2350
2351/**
2352 * ftrace_update_record - set a record that now is tracing or not
2353 * @rec: the record to update
2354 * @enable: set to true if the record is tracing, false to force disable
2355 *
2356 * The records that represent all functions that can be traced need
2357 * to be updated when tracing has been enabled.
2358 */
2359int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2360{
2361 return ftrace_check_record(rec, enable, true);
2362}
2363
2364/**
2365 * ftrace_test_record - check if the record has been enabled or not
2366 * @rec: the record to test
2367 * @enable: set to true to check if enabled, false if it is disabled
2368 *
2369 * The arch code may need to test if a record is already set to
2370 * tracing to determine how to modify the function code that it
2371 * represents.
2372 */
2373int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2374{
2375 return ftrace_check_record(rec, enable, false);
2376}
2377
2378static struct ftrace_ops *
2379ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2380{
2381 struct ftrace_ops *op;
2382 unsigned long ip = rec->ip;
2383
2384 do_for_each_ftrace_op(op, ftrace_ops_list) {
2385
2386 if (!op->trampoline)
2387 continue;
2388
2389 if (hash_contains_ip(ip, op->func_hash))
2390 return op;
2391 } while_for_each_ftrace_op(op);
2392
2393 return NULL;
2394}
2395
2396static struct ftrace_ops *
2397ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2398{
2399 struct ftrace_ops *op;
2400 unsigned long ip = rec->ip;
2401
2402 do_for_each_ftrace_op(op, ftrace_ops_list) {
2403
2404 if (op == op_exclude || !op->trampoline)
2405 continue;
2406
2407 if (hash_contains_ip(ip, op->func_hash))
2408 return op;
2409 } while_for_each_ftrace_op(op);
2410
2411 return NULL;
2412}
2413
2414static struct ftrace_ops *
2415ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2416 struct ftrace_ops *op)
2417{
2418 unsigned long ip = rec->ip;
2419
2420 while_for_each_ftrace_op(op) {
2421
2422 if (!op->trampoline)
2423 continue;
2424
2425 if (hash_contains_ip(ip, op->func_hash))
2426 return op;
2427 }
2428
2429 return NULL;
2430}
2431
2432static struct ftrace_ops *
2433ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2434{
2435 struct ftrace_ops *op;
2436 unsigned long ip = rec->ip;
2437
2438 /*
2439 * Need to check removed ops first.
2440 * If they are being removed, and this rec has a tramp,
2441 * and this rec is in the ops list, then it would be the
2442 * one with the tramp.
2443 */
2444 if (removed_ops) {
2445 if (hash_contains_ip(ip, &removed_ops->old_hash))
2446 return removed_ops;
2447 }
2448
2449 /*
2450 * Need to find the current trampoline for a rec.
2451 * Now, a trampoline is only attached to a rec if there
2452 * was a single 'ops' attached to it. But this can be called
2453 * when we are adding another op to the rec or removing the
2454 * current one. Thus, if the op is being added, we can
2455 * ignore it because it hasn't attached itself to the rec
2456 * yet.
2457 *
2458 * If an ops is being modified (hooking to different functions)
2459 * then we don't care about the new functions that are being
2460 * added, just the old ones (that are probably being removed).
2461 *
2462 * If we are adding an ops to a function that already is using
2463 * a trampoline, it needs to be removed (trampolines are only
2464 * for single ops connected), then an ops that is not being
2465 * modified also needs to be checked.
2466 */
2467 do_for_each_ftrace_op(op, ftrace_ops_list) {
2468
2469 if (!op->trampoline)
2470 continue;
2471
2472 /*
2473 * If the ops is being added, it hasn't gotten to
2474 * the point to be removed from this tree yet.
2475 */
2476 if (op->flags & FTRACE_OPS_FL_ADDING)
2477 continue;
2478
2479
2480 /*
2481 * If the ops is being modified and is in the old
2482 * hash, then it is probably being removed from this
2483 * function.
2484 */
2485 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2486 hash_contains_ip(ip, &op->old_hash))
2487 return op;
2488 /*
2489 * If the ops is not being added or modified, and it's
2490 * in its normal filter hash, then this must be the one
2491 * we want!
2492 */
2493 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2494 hash_contains_ip(ip, op->func_hash))
2495 return op;
2496
2497 } while_for_each_ftrace_op(op);
2498
2499 return NULL;
2500}
2501
2502static struct ftrace_ops *
2503ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2504{
2505 struct ftrace_ops *op;
2506 unsigned long ip = rec->ip;
2507
2508 do_for_each_ftrace_op(op, ftrace_ops_list) {
2509 /* pass rec in as regs to have non-NULL val */
2510 if (hash_contains_ip(ip, op->func_hash))
2511 return op;
2512 } while_for_each_ftrace_op(op);
2513
2514 return NULL;
2515}
2516
2517struct ftrace_ops *
2518ftrace_find_unique_ops(struct dyn_ftrace *rec)
2519{
2520 struct ftrace_ops *op, *found = NULL;
2521 unsigned long ip = rec->ip;
2522
2523 do_for_each_ftrace_op(op, ftrace_ops_list) {
2524
2525 if (hash_contains_ip(ip, op->func_hash)) {
2526 if (found)
2527 return NULL;
2528 found = op;
2529 }
2530
2531 } while_for_each_ftrace_op(op);
2532
2533 return found;
2534}
2535
2536#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2537/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2538static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
2539static DEFINE_MUTEX(direct_mutex);
2540int ftrace_direct_func_count;
2541
2542/*
2543 * Search the direct_functions hash to see if the given instruction pointer
2544 * has a direct caller attached to it.
2545 */
2546unsigned long ftrace_find_rec_direct(unsigned long ip)
2547{
2548 struct ftrace_func_entry *entry;
2549
2550 entry = __ftrace_lookup_ip(direct_functions, ip);
2551 if (!entry)
2552 return 0;
2553
2554 return entry->direct;
2555}
2556
2557static void call_direct_funcs(unsigned long ip, unsigned long pip,
2558 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2559{
2560 unsigned long addr = READ_ONCE(ops->direct_call);
2561
2562 if (!addr)
2563 return;
2564
2565 arch_ftrace_set_direct_caller(fregs, addr);
2566}
2567#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2568
2569/**
2570 * ftrace_get_addr_new - Get the call address to set to
2571 * @rec: The ftrace record descriptor
2572 *
2573 * If the record has the FTRACE_FL_REGS set, that means that it
2574 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2575 * is not set, then it wants to convert to the normal callback.
2576 *
2577 * Returns the address of the trampoline to set to
2578 */
2579unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2580{
2581 struct ftrace_ops *ops;
2582 unsigned long addr;
2583
2584 if ((rec->flags & FTRACE_FL_DIRECT) &&
2585 (ftrace_rec_count(rec) == 1)) {
2586 addr = ftrace_find_rec_direct(rec->ip);
2587 if (addr)
2588 return addr;
2589 WARN_ON_ONCE(1);
2590 }
2591
2592 /* Trampolines take precedence over regs */
2593 if (rec->flags & FTRACE_FL_TRAMP) {
2594 ops = ftrace_find_tramp_ops_new(rec);
2595 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2596 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2597 (void *)rec->ip, (void *)rec->ip, rec->flags);
2598 /* Ftrace is shutting down, return anything */
2599 return (unsigned long)FTRACE_ADDR;
2600 }
2601 return ops->trampoline;
2602 }
2603
2604 if (rec->flags & FTRACE_FL_REGS)
2605 return (unsigned long)FTRACE_REGS_ADDR;
2606 else
2607 return (unsigned long)FTRACE_ADDR;
2608}
2609
2610/**
2611 * ftrace_get_addr_curr - Get the call address that is already there
2612 * @rec: The ftrace record descriptor
2613 *
2614 * The FTRACE_FL_REGS_EN is set when the record already points to
2615 * a function that saves all the regs. Basically the '_EN' version
2616 * represents the current state of the function.
2617 *
2618 * Returns the address of the trampoline that is currently being called
2619 */
2620unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2621{
2622 struct ftrace_ops *ops;
2623 unsigned long addr;
2624
2625 /* Direct calls take precedence over trampolines */
2626 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2627 addr = ftrace_find_rec_direct(rec->ip);
2628 if (addr)
2629 return addr;
2630 WARN_ON_ONCE(1);
2631 }
2632
2633 /* Trampolines take precedence over regs */
2634 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2635 ops = ftrace_find_tramp_ops_curr(rec);
2636 if (FTRACE_WARN_ON(!ops)) {
2637 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2638 (void *)rec->ip, (void *)rec->ip);
2639 /* Ftrace is shutting down, return anything */
2640 return (unsigned long)FTRACE_ADDR;
2641 }
2642 return ops->trampoline;
2643 }
2644
2645 if (rec->flags & FTRACE_FL_REGS_EN)
2646 return (unsigned long)FTRACE_REGS_ADDR;
2647 else
2648 return (unsigned long)FTRACE_ADDR;
2649}
2650
2651static int
2652__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2653{
2654 unsigned long ftrace_old_addr;
2655 unsigned long ftrace_addr;
2656 int ret;
2657
2658 ftrace_addr = ftrace_get_addr_new(rec);
2659
2660 /* This needs to be done before we call ftrace_update_record */
2661 ftrace_old_addr = ftrace_get_addr_curr(rec);
2662
2663 ret = ftrace_update_record(rec, enable);
2664
2665 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2666
2667 switch (ret) {
2668 case FTRACE_UPDATE_IGNORE:
2669 return 0;
2670
2671 case FTRACE_UPDATE_MAKE_CALL:
2672 ftrace_bug_type = FTRACE_BUG_CALL;
2673 return ftrace_make_call(rec, ftrace_addr);
2674
2675 case FTRACE_UPDATE_MAKE_NOP:
2676 ftrace_bug_type = FTRACE_BUG_NOP;
2677 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2678
2679 case FTRACE_UPDATE_MODIFY_CALL:
2680 ftrace_bug_type = FTRACE_BUG_UPDATE;
2681 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2682 }
2683
2684 return -1; /* unknown ftrace bug */
2685}
2686
2687void __weak ftrace_replace_code(int mod_flags)
2688{
2689 struct dyn_ftrace *rec;
2690 struct ftrace_page *pg;
2691 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2692 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2693 int failed;
2694
2695 if (unlikely(ftrace_disabled))
2696 return;
2697
2698 do_for_each_ftrace_rec(pg, rec) {
2699
2700 if (skip_record(rec))
2701 continue;
2702
2703 failed = __ftrace_replace_code(rec, enable);
2704 if (failed) {
2705 ftrace_bug(failed, rec);
2706 /* Stop processing */
2707 return;
2708 }
2709 if (schedulable)
2710 cond_resched();
2711 } while_for_each_ftrace_rec();
2712}
2713
2714struct ftrace_rec_iter {
2715 struct ftrace_page *pg;
2716 int index;
2717};
2718
2719/**
2720 * ftrace_rec_iter_start - start up iterating over traced functions
2721 *
2722 * Returns an iterator handle that is used to iterate over all
2723 * the records that represent address locations where functions
2724 * are traced.
2725 *
2726 * May return NULL if no records are available.
2727 */
2728struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2729{
2730 /*
2731 * We only use a single iterator.
2732 * Protected by the ftrace_lock mutex.
2733 */
2734 static struct ftrace_rec_iter ftrace_rec_iter;
2735 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2736
2737 iter->pg = ftrace_pages_start;
2738 iter->index = 0;
2739
2740 /* Could have empty pages */
2741 while (iter->pg && !iter->pg->index)
2742 iter->pg = iter->pg->next;
2743
2744 if (!iter->pg)
2745 return NULL;
2746
2747 return iter;
2748}
2749
2750/**
2751 * ftrace_rec_iter_next - get the next record to process.
2752 * @iter: The handle to the iterator.
2753 *
2754 * Returns the next iterator after the given iterator @iter.
2755 */
2756struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2757{
2758 iter->index++;
2759
2760 if (iter->index >= iter->pg->index) {
2761 iter->pg = iter->pg->next;
2762 iter->index = 0;
2763
2764 /* Could have empty pages */
2765 while (iter->pg && !iter->pg->index)
2766 iter->pg = iter->pg->next;
2767 }
2768
2769 if (!iter->pg)
2770 return NULL;
2771
2772 return iter;
2773}
2774
2775/**
2776 * ftrace_rec_iter_record - get the record at the iterator location
2777 * @iter: The current iterator location
2778 *
2779 * Returns the record that the current @iter is at.
2780 */
2781struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2782{
2783 return &iter->pg->records[iter->index];
2784}
2785
2786static int
2787ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2788{
2789 int ret;
2790
2791 if (unlikely(ftrace_disabled))
2792 return 0;
2793
2794 ret = ftrace_init_nop(mod, rec);
2795 if (ret) {
2796 ftrace_bug_type = FTRACE_BUG_INIT;
2797 ftrace_bug(ret, rec);
2798 return 0;
2799 }
2800 return 1;
2801}
2802
2803/*
2804 * archs can override this function if they must do something
2805 * before the modifying code is performed.
2806 */
2807void __weak ftrace_arch_code_modify_prepare(void)
2808{
2809}
2810
2811/*
2812 * archs can override this function if they must do something
2813 * after the modifying code is performed.
2814 */
2815void __weak ftrace_arch_code_modify_post_process(void)
2816{
2817}
2818
2819static int update_ftrace_func(ftrace_func_t func)
2820{
2821 static ftrace_func_t save_func;
2822
2823 /* Avoid updating if it hasn't changed */
2824 if (func == save_func)
2825 return 0;
2826
2827 save_func = func;
2828
2829 return ftrace_update_ftrace_func(func);
2830}
2831
2832void ftrace_modify_all_code(int command)
2833{
2834 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2835 int mod_flags = 0;
2836 int err = 0;
2837
2838 if (command & FTRACE_MAY_SLEEP)
2839 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2840
2841 /*
2842 * If the ftrace_caller calls a ftrace_ops func directly,
2843 * we need to make sure that it only traces functions it
2844 * expects to trace. When doing the switch of functions,
2845 * we need to update to the ftrace_ops_list_func first
2846 * before the transition between old and new calls are set,
2847 * as the ftrace_ops_list_func will check the ops hashes
2848 * to make sure the ops are having the right functions
2849 * traced.
2850 */
2851 if (update) {
2852 err = update_ftrace_func(ftrace_ops_list_func);
2853 if (FTRACE_WARN_ON(err))
2854 return;
2855 }
2856
2857 if (command & FTRACE_UPDATE_CALLS)
2858 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2859 else if (command & FTRACE_DISABLE_CALLS)
2860 ftrace_replace_code(mod_flags);
2861
2862 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2863 function_trace_op = set_function_trace_op;
2864 smp_wmb();
2865 /* If irqs are disabled, we are in stop machine */
2866 if (!irqs_disabled())
2867 smp_call_function(ftrace_sync_ipi, NULL, 1);
2868 err = update_ftrace_func(ftrace_trace_function);
2869 if (FTRACE_WARN_ON(err))
2870 return;
2871 }
2872
2873 if (command & FTRACE_START_FUNC_RET)
2874 err = ftrace_enable_ftrace_graph_caller();
2875 else if (command & FTRACE_STOP_FUNC_RET)
2876 err = ftrace_disable_ftrace_graph_caller();
2877 FTRACE_WARN_ON(err);
2878}
2879
2880static int __ftrace_modify_code(void *data)
2881{
2882 int *command = data;
2883
2884 ftrace_modify_all_code(*command);
2885
2886 return 0;
2887}
2888
2889/**
2890 * ftrace_run_stop_machine - go back to the stop machine method
2891 * @command: The command to tell ftrace what to do
2892 *
2893 * If an arch needs to fall back to the stop machine method, the
2894 * it can call this function.
2895 */
2896void ftrace_run_stop_machine(int command)
2897{
2898 stop_machine(__ftrace_modify_code, &command, NULL);
2899}
2900
2901/**
2902 * arch_ftrace_update_code - modify the code to trace or not trace
2903 * @command: The command that needs to be done
2904 *
2905 * Archs can override this function if it does not need to
2906 * run stop_machine() to modify code.
2907 */
2908void __weak arch_ftrace_update_code(int command)
2909{
2910 ftrace_run_stop_machine(command);
2911}
2912
2913static void ftrace_run_update_code(int command)
2914{
2915 ftrace_arch_code_modify_prepare();
2916
2917 /*
2918 * By default we use stop_machine() to modify the code.
2919 * But archs can do what ever they want as long as it
2920 * is safe. The stop_machine() is the safest, but also
2921 * produces the most overhead.
2922 */
2923 arch_ftrace_update_code(command);
2924
2925 ftrace_arch_code_modify_post_process();
2926}
2927
2928static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2929 struct ftrace_ops_hash *old_hash)
2930{
2931 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2932 ops->old_hash.filter_hash = old_hash->filter_hash;
2933 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2934 ftrace_run_update_code(command);
2935 ops->old_hash.filter_hash = NULL;
2936 ops->old_hash.notrace_hash = NULL;
2937 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2938}
2939
2940static ftrace_func_t saved_ftrace_func;
2941static int ftrace_start_up;
2942
2943void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2944{
2945}
2946
2947/* List of trace_ops that have allocated trampolines */
2948static LIST_HEAD(ftrace_ops_trampoline_list);
2949
2950static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2951{
2952 lockdep_assert_held(&ftrace_lock);
2953 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2954}
2955
2956static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2957{
2958 lockdep_assert_held(&ftrace_lock);
2959 list_del_rcu(&ops->list);
2960 synchronize_rcu();
2961}
2962
2963/*
2964 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2965 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2966 * not a module.
2967 */
2968#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2969#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2970
2971static void ftrace_trampoline_free(struct ftrace_ops *ops)
2972{
2973 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2974 ops->trampoline) {
2975 /*
2976 * Record the text poke event before the ksymbol unregister
2977 * event.
2978 */
2979 perf_event_text_poke((void *)ops->trampoline,
2980 (void *)ops->trampoline,
2981 ops->trampoline_size, NULL, 0);
2982 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2983 ops->trampoline, ops->trampoline_size,
2984 true, FTRACE_TRAMPOLINE_SYM);
2985 /* Remove from kallsyms after the perf events */
2986 ftrace_remove_trampoline_from_kallsyms(ops);
2987 }
2988
2989 arch_ftrace_trampoline_free(ops);
2990}
2991
2992static void ftrace_startup_enable(int command)
2993{
2994 if (saved_ftrace_func != ftrace_trace_function) {
2995 saved_ftrace_func = ftrace_trace_function;
2996 command |= FTRACE_UPDATE_TRACE_FUNC;
2997 }
2998
2999 if (!command || !ftrace_enabled)
3000 return;
3001
3002 ftrace_run_update_code(command);
3003}
3004
3005static void ftrace_startup_all(int command)
3006{
3007 update_all_ops = true;
3008 ftrace_startup_enable(command);
3009 update_all_ops = false;
3010}
3011
3012int ftrace_startup(struct ftrace_ops *ops, int command)
3013{
3014 int ret;
3015
3016 if (unlikely(ftrace_disabled))
3017 return -ENODEV;
3018
3019 ret = __register_ftrace_function(ops);
3020 if (ret)
3021 return ret;
3022
3023 ftrace_start_up++;
3024
3025 /*
3026 * Note that ftrace probes uses this to start up
3027 * and modify functions it will probe. But we still
3028 * set the ADDING flag for modification, as probes
3029 * do not have trampolines. If they add them in the
3030 * future, then the probes will need to distinguish
3031 * between adding and updating probes.
3032 */
3033 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3034
3035 ret = ftrace_hash_ipmodify_enable(ops);
3036 if (ret < 0) {
3037 /* Rollback registration process */
3038 __unregister_ftrace_function(ops);
3039 ftrace_start_up--;
3040 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3041 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3042 ftrace_trampoline_free(ops);
3043 return ret;
3044 }
3045
3046 if (ftrace_hash_rec_enable(ops, 1))
3047 command |= FTRACE_UPDATE_CALLS;
3048
3049 ftrace_startup_enable(command);
3050
3051 /*
3052 * If ftrace is in an undefined state, we just remove ops from list
3053 * to prevent the NULL pointer, instead of totally rolling it back and
3054 * free trampoline, because those actions could cause further damage.
3055 */
3056 if (unlikely(ftrace_disabled)) {
3057 __unregister_ftrace_function(ops);
3058 return -ENODEV;
3059 }
3060
3061 ops->flags &= ~FTRACE_OPS_FL_ADDING;
3062
3063 return 0;
3064}
3065
3066int ftrace_shutdown(struct ftrace_ops *ops, int command)
3067{
3068 int ret;
3069
3070 if (unlikely(ftrace_disabled))
3071 return -ENODEV;
3072
3073 ret = __unregister_ftrace_function(ops);
3074 if (ret)
3075 return ret;
3076
3077 ftrace_start_up--;
3078 /*
3079 * Just warn in case of unbalance, no need to kill ftrace, it's not
3080 * critical but the ftrace_call callers may be never nopped again after
3081 * further ftrace uses.
3082 */
3083 WARN_ON_ONCE(ftrace_start_up < 0);
3084
3085 /* Disabling ipmodify never fails */
3086 ftrace_hash_ipmodify_disable(ops);
3087
3088 if (ftrace_hash_rec_disable(ops, 1))
3089 command |= FTRACE_UPDATE_CALLS;
3090
3091 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3092
3093 if (saved_ftrace_func != ftrace_trace_function) {
3094 saved_ftrace_func = ftrace_trace_function;
3095 command |= FTRACE_UPDATE_TRACE_FUNC;
3096 }
3097
3098 if (!command || !ftrace_enabled)
3099 goto out;
3100
3101 /*
3102 * If the ops uses a trampoline, then it needs to be
3103 * tested first on update.
3104 */
3105 ops->flags |= FTRACE_OPS_FL_REMOVING;
3106 removed_ops = ops;
3107
3108 /* The trampoline logic checks the old hashes */
3109 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3110 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3111
3112 ftrace_run_update_code(command);
3113
3114 /*
3115 * If there's no more ops registered with ftrace, run a
3116 * sanity check to make sure all rec flags are cleared.
3117 */
3118 if (rcu_dereference_protected(ftrace_ops_list,
3119 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3120 struct ftrace_page *pg;
3121 struct dyn_ftrace *rec;
3122
3123 do_for_each_ftrace_rec(pg, rec) {
3124 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3125 pr_warn(" %pS flags:%lx\n",
3126 (void *)rec->ip, rec->flags);
3127 } while_for_each_ftrace_rec();
3128 }
3129
3130 ops->old_hash.filter_hash = NULL;
3131 ops->old_hash.notrace_hash = NULL;
3132
3133 removed_ops = NULL;
3134 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3135
3136out:
3137 /*
3138 * Dynamic ops may be freed, we must make sure that all
3139 * callers are done before leaving this function.
3140 */
3141 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3142 /*
3143 * We need to do a hard force of sched synchronization.
3144 * This is because we use preempt_disable() to do RCU, but
3145 * the function tracers can be called where RCU is not watching
3146 * (like before user_exit()). We can not rely on the RCU
3147 * infrastructure to do the synchronization, thus we must do it
3148 * ourselves.
3149 */
3150 synchronize_rcu_tasks_rude();
3151
3152 /*
3153 * When the kernel is preemptive, tasks can be preempted
3154 * while on a ftrace trampoline. Just scheduling a task on
3155 * a CPU is not good enough to flush them. Calling
3156 * synchronize_rcu_tasks() will wait for those tasks to
3157 * execute and either schedule voluntarily or enter user space.
3158 */
3159 if (IS_ENABLED(CONFIG_PREEMPTION))
3160 synchronize_rcu_tasks();
3161
3162 ftrace_trampoline_free(ops);
3163 }
3164
3165 return 0;
3166}
3167
3168static u64 ftrace_update_time;
3169unsigned long ftrace_update_tot_cnt;
3170unsigned long ftrace_number_of_pages;
3171unsigned long ftrace_number_of_groups;
3172
3173static inline int ops_traces_mod(struct ftrace_ops *ops)
3174{
3175 /*
3176 * Filter_hash being empty will default to trace module.
3177 * But notrace hash requires a test of individual module functions.
3178 */
3179 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3180 ftrace_hash_empty(ops->func_hash->notrace_hash);
3181}
3182
3183static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3184{
3185 bool init_nop = ftrace_need_init_nop();
3186 struct ftrace_page *pg;
3187 struct dyn_ftrace *p;
3188 u64 start, stop;
3189 unsigned long update_cnt = 0;
3190 unsigned long rec_flags = 0;
3191 int i;
3192
3193 start = ftrace_now(raw_smp_processor_id());
3194
3195 /*
3196 * When a module is loaded, this function is called to convert
3197 * the calls to mcount in its text to nops, and also to create
3198 * an entry in the ftrace data. Now, if ftrace is activated
3199 * after this call, but before the module sets its text to
3200 * read-only, the modification of enabling ftrace can fail if
3201 * the read-only is done while ftrace is converting the calls.
3202 * To prevent this, the module's records are set as disabled
3203 * and will be enabled after the call to set the module's text
3204 * to read-only.
3205 */
3206 if (mod)
3207 rec_flags |= FTRACE_FL_DISABLED;
3208
3209 for (pg = new_pgs; pg; pg = pg->next) {
3210
3211 for (i = 0; i < pg->index; i++) {
3212
3213 /* If something went wrong, bail without enabling anything */
3214 if (unlikely(ftrace_disabled))
3215 return -1;
3216
3217 p = &pg->records[i];
3218 p->flags = rec_flags;
3219
3220 /*
3221 * Do the initial record conversion from mcount jump
3222 * to the NOP instructions.
3223 */
3224 if (init_nop && !ftrace_nop_initialize(mod, p))
3225 break;
3226
3227 update_cnt++;
3228 }
3229 }
3230
3231 stop = ftrace_now(raw_smp_processor_id());
3232 ftrace_update_time = stop - start;
3233 ftrace_update_tot_cnt += update_cnt;
3234
3235 return 0;
3236}
3237
3238static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3239{
3240 int order;
3241 int pages;
3242 int cnt;
3243
3244 if (WARN_ON(!count))
3245 return -EINVAL;
3246
3247 /* We want to fill as much as possible, with no empty pages */
3248 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3249 order = fls(pages) - 1;
3250
3251 again:
3252 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3253
3254 if (!pg->records) {
3255 /* if we can't allocate this size, try something smaller */
3256 if (!order)
3257 return -ENOMEM;
3258 order--;
3259 goto again;
3260 }
3261
3262 ftrace_number_of_pages += 1 << order;
3263 ftrace_number_of_groups++;
3264
3265 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3266 pg->order = order;
3267
3268 if (cnt > count)
3269 cnt = count;
3270
3271 return cnt;
3272}
3273
3274static void ftrace_free_pages(struct ftrace_page *pages)
3275{
3276 struct ftrace_page *pg = pages;
3277
3278 while (pg) {
3279 if (pg->records) {
3280 free_pages((unsigned long)pg->records, pg->order);
3281 ftrace_number_of_pages -= 1 << pg->order;
3282 }
3283 pages = pg->next;
3284 kfree(pg);
3285 pg = pages;
3286 ftrace_number_of_groups--;
3287 }
3288}
3289
3290static struct ftrace_page *
3291ftrace_allocate_pages(unsigned long num_to_init)
3292{
3293 struct ftrace_page *start_pg;
3294 struct ftrace_page *pg;
3295 int cnt;
3296
3297 if (!num_to_init)
3298 return NULL;
3299
3300 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3301 if (!pg)
3302 return NULL;
3303
3304 /*
3305 * Try to allocate as much as possible in one continues
3306 * location that fills in all of the space. We want to
3307 * waste as little space as possible.
3308 */
3309 for (;;) {
3310 cnt = ftrace_allocate_records(pg, num_to_init);
3311 if (cnt < 0)
3312 goto free_pages;
3313
3314 num_to_init -= cnt;
3315 if (!num_to_init)
3316 break;
3317
3318 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3319 if (!pg->next)
3320 goto free_pages;
3321
3322 pg = pg->next;
3323 }
3324
3325 return start_pg;
3326
3327 free_pages:
3328 ftrace_free_pages(start_pg);
3329 pr_info("ftrace: FAILED to allocate memory for functions\n");
3330 return NULL;
3331}
3332
3333#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3334
3335struct ftrace_iterator {
3336 loff_t pos;
3337 loff_t func_pos;
3338 loff_t mod_pos;
3339 struct ftrace_page *pg;
3340 struct dyn_ftrace *func;
3341 struct ftrace_func_probe *probe;
3342 struct ftrace_func_entry *probe_entry;
3343 struct trace_parser parser;
3344 struct ftrace_hash *hash;
3345 struct ftrace_ops *ops;
3346 struct trace_array *tr;
3347 struct list_head *mod_list;
3348 int pidx;
3349 int idx;
3350 unsigned flags;
3351};
3352
3353static void *
3354t_probe_next(struct seq_file *m, loff_t *pos)
3355{
3356 struct ftrace_iterator *iter = m->private;
3357 struct trace_array *tr = iter->ops->private;
3358 struct list_head *func_probes;
3359 struct ftrace_hash *hash;
3360 struct list_head *next;
3361 struct hlist_node *hnd = NULL;
3362 struct hlist_head *hhd;
3363 int size;
3364
3365 (*pos)++;
3366 iter->pos = *pos;
3367
3368 if (!tr)
3369 return NULL;
3370
3371 func_probes = &tr->func_probes;
3372 if (list_empty(func_probes))
3373 return NULL;
3374
3375 if (!iter->probe) {
3376 next = func_probes->next;
3377 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3378 }
3379
3380 if (iter->probe_entry)
3381 hnd = &iter->probe_entry->hlist;
3382
3383 hash = iter->probe->ops.func_hash->filter_hash;
3384
3385 /*
3386 * A probe being registered may temporarily have an empty hash
3387 * and it's at the end of the func_probes list.
3388 */
3389 if (!hash || hash == EMPTY_HASH)
3390 return NULL;
3391
3392 size = 1 << hash->size_bits;
3393
3394 retry:
3395 if (iter->pidx >= size) {
3396 if (iter->probe->list.next == func_probes)
3397 return NULL;
3398 next = iter->probe->list.next;
3399 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3400 hash = iter->probe->ops.func_hash->filter_hash;
3401 size = 1 << hash->size_bits;
3402 iter->pidx = 0;
3403 }
3404
3405 hhd = &hash->buckets[iter->pidx];
3406
3407 if (hlist_empty(hhd)) {
3408 iter->pidx++;
3409 hnd = NULL;
3410 goto retry;
3411 }
3412
3413 if (!hnd)
3414 hnd = hhd->first;
3415 else {
3416 hnd = hnd->next;
3417 if (!hnd) {
3418 iter->pidx++;
3419 goto retry;
3420 }
3421 }
3422
3423 if (WARN_ON_ONCE(!hnd))
3424 return NULL;
3425
3426 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3427
3428 return iter;
3429}
3430
3431static void *t_probe_start(struct seq_file *m, loff_t *pos)
3432{
3433 struct ftrace_iterator *iter = m->private;
3434 void *p = NULL;
3435 loff_t l;
3436
3437 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3438 return NULL;
3439
3440 if (iter->mod_pos > *pos)
3441 return NULL;
3442
3443 iter->probe = NULL;
3444 iter->probe_entry = NULL;
3445 iter->pidx = 0;
3446 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3447 p = t_probe_next(m, &l);
3448 if (!p)
3449 break;
3450 }
3451 if (!p)
3452 return NULL;
3453
3454 /* Only set this if we have an item */
3455 iter->flags |= FTRACE_ITER_PROBE;
3456
3457 return iter;
3458}
3459
3460static int
3461t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3462{
3463 struct ftrace_func_entry *probe_entry;
3464 struct ftrace_probe_ops *probe_ops;
3465 struct ftrace_func_probe *probe;
3466
3467 probe = iter->probe;
3468 probe_entry = iter->probe_entry;
3469
3470 if (WARN_ON_ONCE(!probe || !probe_entry))
3471 return -EIO;
3472
3473 probe_ops = probe->probe_ops;
3474
3475 if (probe_ops->print)
3476 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3477
3478 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3479 (void *)probe_ops->func);
3480
3481 return 0;
3482}
3483
3484static void *
3485t_mod_next(struct seq_file *m, loff_t *pos)
3486{
3487 struct ftrace_iterator *iter = m->private;
3488 struct trace_array *tr = iter->tr;
3489
3490 (*pos)++;
3491 iter->pos = *pos;
3492
3493 iter->mod_list = iter->mod_list->next;
3494
3495 if (iter->mod_list == &tr->mod_trace ||
3496 iter->mod_list == &tr->mod_notrace) {
3497 iter->flags &= ~FTRACE_ITER_MOD;
3498 return NULL;
3499 }
3500
3501 iter->mod_pos = *pos;
3502
3503 return iter;
3504}
3505
3506static void *t_mod_start(struct seq_file *m, loff_t *pos)
3507{
3508 struct ftrace_iterator *iter = m->private;
3509 void *p = NULL;
3510 loff_t l;
3511
3512 if (iter->func_pos > *pos)
3513 return NULL;
3514
3515 iter->mod_pos = iter->func_pos;
3516
3517 /* probes are only available if tr is set */
3518 if (!iter->tr)
3519 return NULL;
3520
3521 for (l = 0; l <= (*pos - iter->func_pos); ) {
3522 p = t_mod_next(m, &l);
3523 if (!p)
3524 break;
3525 }
3526 if (!p) {
3527 iter->flags &= ~FTRACE_ITER_MOD;
3528 return t_probe_start(m, pos);
3529 }
3530
3531 /* Only set this if we have an item */
3532 iter->flags |= FTRACE_ITER_MOD;
3533
3534 return iter;
3535}
3536
3537static int
3538t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3539{
3540 struct ftrace_mod_load *ftrace_mod;
3541 struct trace_array *tr = iter->tr;
3542
3543 if (WARN_ON_ONCE(!iter->mod_list) ||
3544 iter->mod_list == &tr->mod_trace ||
3545 iter->mod_list == &tr->mod_notrace)
3546 return -EIO;
3547
3548 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3549
3550 if (ftrace_mod->func)
3551 seq_printf(m, "%s", ftrace_mod->func);
3552 else
3553 seq_putc(m, '*');
3554
3555 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3556
3557 return 0;
3558}
3559
3560static void *
3561t_func_next(struct seq_file *m, loff_t *pos)
3562{
3563 struct ftrace_iterator *iter = m->private;
3564 struct dyn_ftrace *rec = NULL;
3565
3566 (*pos)++;
3567
3568 retry:
3569 if (iter->idx >= iter->pg->index) {
3570 if (iter->pg->next) {
3571 iter->pg = iter->pg->next;
3572 iter->idx = 0;
3573 goto retry;
3574 }
3575 } else {
3576 rec = &iter->pg->records[iter->idx++];
3577 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3578 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3579
3580 ((iter->flags & FTRACE_ITER_ENABLED) &&
3581 !(rec->flags & FTRACE_FL_ENABLED)) ||
3582
3583 ((iter->flags & FTRACE_ITER_TOUCHED) &&
3584 !(rec->flags & FTRACE_FL_TOUCHED))) {
3585
3586 rec = NULL;
3587 goto retry;
3588 }
3589 }
3590
3591 if (!rec)
3592 return NULL;
3593
3594 iter->pos = iter->func_pos = *pos;
3595 iter->func = rec;
3596
3597 return iter;
3598}
3599
3600static void *
3601t_next(struct seq_file *m, void *v, loff_t *pos)
3602{
3603 struct ftrace_iterator *iter = m->private;
3604 loff_t l = *pos; /* t_probe_start() must use original pos */
3605 void *ret;
3606
3607 if (unlikely(ftrace_disabled))
3608 return NULL;
3609
3610 if (iter->flags & FTRACE_ITER_PROBE)
3611 return t_probe_next(m, pos);
3612
3613 if (iter->flags & FTRACE_ITER_MOD)
3614 return t_mod_next(m, pos);
3615
3616 if (iter->flags & FTRACE_ITER_PRINTALL) {
3617 /* next must increment pos, and t_probe_start does not */
3618 (*pos)++;
3619 return t_mod_start(m, &l);
3620 }
3621
3622 ret = t_func_next(m, pos);
3623
3624 if (!ret)
3625 return t_mod_start(m, &l);
3626
3627 return ret;
3628}
3629
3630static void reset_iter_read(struct ftrace_iterator *iter)
3631{
3632 iter->pos = 0;
3633 iter->func_pos = 0;
3634 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3635}
3636
3637static void *t_start(struct seq_file *m, loff_t *pos)
3638{
3639 struct ftrace_iterator *iter = m->private;
3640 void *p = NULL;
3641 loff_t l;
3642
3643 mutex_lock(&ftrace_lock);
3644
3645 if (unlikely(ftrace_disabled))
3646 return NULL;
3647
3648 /*
3649 * If an lseek was done, then reset and start from beginning.
3650 */
3651 if (*pos < iter->pos)
3652 reset_iter_read(iter);
3653
3654 /*
3655 * For set_ftrace_filter reading, if we have the filter
3656 * off, we can short cut and just print out that all
3657 * functions are enabled.
3658 */
3659 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3660 ftrace_hash_empty(iter->hash)) {
3661 iter->func_pos = 1; /* Account for the message */
3662 if (*pos > 0)
3663 return t_mod_start(m, pos);
3664 iter->flags |= FTRACE_ITER_PRINTALL;
3665 /* reset in case of seek/pread */
3666 iter->flags &= ~FTRACE_ITER_PROBE;
3667 return iter;
3668 }
3669
3670 if (iter->flags & FTRACE_ITER_MOD)
3671 return t_mod_start(m, pos);
3672
3673 /*
3674 * Unfortunately, we need to restart at ftrace_pages_start
3675 * every time we let go of the ftrace_mutex. This is because
3676 * those pointers can change without the lock.
3677 */
3678 iter->pg = ftrace_pages_start;
3679 iter->idx = 0;
3680 for (l = 0; l <= *pos; ) {
3681 p = t_func_next(m, &l);
3682 if (!p)
3683 break;
3684 }
3685
3686 if (!p)
3687 return t_mod_start(m, pos);
3688
3689 return iter;
3690}
3691
3692static void t_stop(struct seq_file *m, void *p)
3693{
3694 mutex_unlock(&ftrace_lock);
3695}
3696
3697void * __weak
3698arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3699{
3700 return NULL;
3701}
3702
3703static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3704 struct dyn_ftrace *rec)
3705{
3706 void *ptr;
3707
3708 ptr = arch_ftrace_trampoline_func(ops, rec);
3709 if (ptr)
3710 seq_printf(m, " ->%pS", ptr);
3711}
3712
3713#ifdef FTRACE_MCOUNT_MAX_OFFSET
3714/*
3715 * Weak functions can still have an mcount/fentry that is saved in
3716 * the __mcount_loc section. These can be detected by having a
3717 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3718 * symbol found by kallsyms is not the function that the mcount/fentry
3719 * is part of. The offset is much greater in these cases.
3720 *
3721 * Test the record to make sure that the ip points to a valid kallsyms
3722 * and if not, mark it disabled.
3723 */
3724static int test_for_valid_rec(struct dyn_ftrace *rec)
3725{
3726 char str[KSYM_SYMBOL_LEN];
3727 unsigned long offset;
3728 const char *ret;
3729
3730 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3731
3732 /* Weak functions can cause invalid addresses */
3733 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3734 rec->flags |= FTRACE_FL_DISABLED;
3735 return 0;
3736 }
3737 return 1;
3738}
3739
3740static struct workqueue_struct *ftrace_check_wq __initdata;
3741static struct work_struct ftrace_check_work __initdata;
3742
3743/*
3744 * Scan all the mcount/fentry entries to make sure they are valid.
3745 */
3746static __init void ftrace_check_work_func(struct work_struct *work)
3747{
3748 struct ftrace_page *pg;
3749 struct dyn_ftrace *rec;
3750
3751 mutex_lock(&ftrace_lock);
3752 do_for_each_ftrace_rec(pg, rec) {
3753 test_for_valid_rec(rec);
3754 } while_for_each_ftrace_rec();
3755 mutex_unlock(&ftrace_lock);
3756}
3757
3758static int __init ftrace_check_for_weak_functions(void)
3759{
3760 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3761
3762 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3763
3764 queue_work(ftrace_check_wq, &ftrace_check_work);
3765 return 0;
3766}
3767
3768static int __init ftrace_check_sync(void)
3769{
3770 /* Make sure the ftrace_check updates are finished */
3771 if (ftrace_check_wq)
3772 destroy_workqueue(ftrace_check_wq);
3773 return 0;
3774}
3775
3776late_initcall_sync(ftrace_check_sync);
3777subsys_initcall(ftrace_check_for_weak_functions);
3778
3779static int print_rec(struct seq_file *m, unsigned long ip)
3780{
3781 unsigned long offset;
3782 char str[KSYM_SYMBOL_LEN];
3783 char *modname;
3784 const char *ret;
3785
3786 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3787 /* Weak functions can cause invalid addresses */
3788 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3789 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3790 FTRACE_INVALID_FUNCTION, offset);
3791 ret = NULL;
3792 }
3793
3794 seq_puts(m, str);
3795 if (modname)
3796 seq_printf(m, " [%s]", modname);
3797 return ret == NULL ? -1 : 0;
3798}
3799#else
3800static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3801{
3802 return 1;
3803}
3804
3805static inline int print_rec(struct seq_file *m, unsigned long ip)
3806{
3807 seq_printf(m, "%ps", (void *)ip);
3808 return 0;
3809}
3810#endif
3811
3812static int t_show(struct seq_file *m, void *v)
3813{
3814 struct ftrace_iterator *iter = m->private;
3815 struct dyn_ftrace *rec;
3816
3817 if (iter->flags & FTRACE_ITER_PROBE)
3818 return t_probe_show(m, iter);
3819
3820 if (iter->flags & FTRACE_ITER_MOD)
3821 return t_mod_show(m, iter);
3822
3823 if (iter->flags & FTRACE_ITER_PRINTALL) {
3824 if (iter->flags & FTRACE_ITER_NOTRACE)
3825 seq_puts(m, "#### no functions disabled ####\n");
3826 else
3827 seq_puts(m, "#### all functions enabled ####\n");
3828 return 0;
3829 }
3830
3831 rec = iter->func;
3832
3833 if (!rec)
3834 return 0;
3835
3836 if (iter->flags & FTRACE_ITER_ADDRS)
3837 seq_printf(m, "%lx ", rec->ip);
3838
3839 if (print_rec(m, rec->ip)) {
3840 /* This should only happen when a rec is disabled */
3841 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3842 seq_putc(m, '\n');
3843 return 0;
3844 }
3845
3846 if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3847 struct ftrace_ops *ops;
3848
3849 seq_printf(m, " (%ld)%s%s%s%s%s",
3850 ftrace_rec_count(rec),
3851 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3852 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3853 rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
3854 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
3855 rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
3856 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3857 ops = ftrace_find_tramp_ops_any(rec);
3858 if (ops) {
3859 do {
3860 seq_printf(m, "\ttramp: %pS (%pS)",
3861 (void *)ops->trampoline,
3862 (void *)ops->func);
3863 add_trampoline_func(m, ops, rec);
3864 ops = ftrace_find_tramp_ops_next(rec, ops);
3865 } while (ops);
3866 } else
3867 seq_puts(m, "\ttramp: ERROR!");
3868 } else {
3869 add_trampoline_func(m, NULL, rec);
3870 }
3871 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3872 ops = ftrace_find_unique_ops(rec);
3873 if (ops) {
3874 seq_printf(m, "\tops: %pS (%pS)",
3875 ops, ops->func);
3876 } else {
3877 seq_puts(m, "\tops: ERROR!");
3878 }
3879 }
3880 if (rec->flags & FTRACE_FL_DIRECT) {
3881 unsigned long direct;
3882
3883 direct = ftrace_find_rec_direct(rec->ip);
3884 if (direct)
3885 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3886 }
3887 }
3888
3889 seq_putc(m, '\n');
3890
3891 return 0;
3892}
3893
3894static const struct seq_operations show_ftrace_seq_ops = {
3895 .start = t_start,
3896 .next = t_next,
3897 .stop = t_stop,
3898 .show = t_show,
3899};
3900
3901static int
3902ftrace_avail_open(struct inode *inode, struct file *file)
3903{
3904 struct ftrace_iterator *iter;
3905 int ret;
3906
3907 ret = security_locked_down(LOCKDOWN_TRACEFS);
3908 if (ret)
3909 return ret;
3910
3911 if (unlikely(ftrace_disabled))
3912 return -ENODEV;
3913
3914 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3915 if (!iter)
3916 return -ENOMEM;
3917
3918 iter->pg = ftrace_pages_start;
3919 iter->ops = &global_ops;
3920
3921 return 0;
3922}
3923
3924static int
3925ftrace_enabled_open(struct inode *inode, struct file *file)
3926{
3927 struct ftrace_iterator *iter;
3928
3929 /*
3930 * This shows us what functions are currently being
3931 * traced and by what. Not sure if we want lockdown
3932 * to hide such critical information for an admin.
3933 * Although, perhaps it can show information we don't
3934 * want people to see, but if something is tracing
3935 * something, we probably want to know about it.
3936 */
3937
3938 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3939 if (!iter)
3940 return -ENOMEM;
3941
3942 iter->pg = ftrace_pages_start;
3943 iter->flags = FTRACE_ITER_ENABLED;
3944 iter->ops = &global_ops;
3945
3946 return 0;
3947}
3948
3949static int
3950ftrace_touched_open(struct inode *inode, struct file *file)
3951{
3952 struct ftrace_iterator *iter;
3953
3954 /*
3955 * This shows us what functions have ever been enabled
3956 * (traced, direct, patched, etc). Not sure if we want lockdown
3957 * to hide such critical information for an admin.
3958 * Although, perhaps it can show information we don't
3959 * want people to see, but if something had traced
3960 * something, we probably want to know about it.
3961 */
3962
3963 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3964 if (!iter)
3965 return -ENOMEM;
3966
3967 iter->pg = ftrace_pages_start;
3968 iter->flags = FTRACE_ITER_TOUCHED;
3969 iter->ops = &global_ops;
3970
3971 return 0;
3972}
3973
3974static int
3975ftrace_avail_addrs_open(struct inode *inode, struct file *file)
3976{
3977 struct ftrace_iterator *iter;
3978 int ret;
3979
3980 ret = security_locked_down(LOCKDOWN_TRACEFS);
3981 if (ret)
3982 return ret;
3983
3984 if (unlikely(ftrace_disabled))
3985 return -ENODEV;
3986
3987 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3988 if (!iter)
3989 return -ENOMEM;
3990
3991 iter->pg = ftrace_pages_start;
3992 iter->flags = FTRACE_ITER_ADDRS;
3993 iter->ops = &global_ops;
3994
3995 return 0;
3996}
3997
3998/**
3999 * ftrace_regex_open - initialize function tracer filter files
4000 * @ops: The ftrace_ops that hold the hash filters
4001 * @flag: The type of filter to process
4002 * @inode: The inode, usually passed in to your open routine
4003 * @file: The file, usually passed in to your open routine
4004 *
4005 * ftrace_regex_open() initializes the filter files for the
4006 * @ops. Depending on @flag it may process the filter hash or
4007 * the notrace hash of @ops. With this called from the open
4008 * routine, you can use ftrace_filter_write() for the write
4009 * routine if @flag has FTRACE_ITER_FILTER set, or
4010 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4011 * tracing_lseek() should be used as the lseek routine, and
4012 * release must call ftrace_regex_release().
4013 */
4014int
4015ftrace_regex_open(struct ftrace_ops *ops, int flag,
4016 struct inode *inode, struct file *file)
4017{
4018 struct ftrace_iterator *iter;
4019 struct ftrace_hash *hash;
4020 struct list_head *mod_head;
4021 struct trace_array *tr = ops->private;
4022 int ret = -ENOMEM;
4023
4024 ftrace_ops_init(ops);
4025
4026 if (unlikely(ftrace_disabled))
4027 return -ENODEV;
4028
4029 if (tracing_check_open_get_tr(tr))
4030 return -ENODEV;
4031
4032 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4033 if (!iter)
4034 goto out;
4035
4036 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4037 goto out;
4038
4039 iter->ops = ops;
4040 iter->flags = flag;
4041 iter->tr = tr;
4042
4043 mutex_lock(&ops->func_hash->regex_lock);
4044
4045 if (flag & FTRACE_ITER_NOTRACE) {
4046 hash = ops->func_hash->notrace_hash;
4047 mod_head = tr ? &tr->mod_notrace : NULL;
4048 } else {
4049 hash = ops->func_hash->filter_hash;
4050 mod_head = tr ? &tr->mod_trace : NULL;
4051 }
4052
4053 iter->mod_list = mod_head;
4054
4055 if (file->f_mode & FMODE_WRITE) {
4056 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4057
4058 if (file->f_flags & O_TRUNC) {
4059 iter->hash = alloc_ftrace_hash(size_bits);
4060 clear_ftrace_mod_list(mod_head);
4061 } else {
4062 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4063 }
4064
4065 if (!iter->hash) {
4066 trace_parser_put(&iter->parser);
4067 goto out_unlock;
4068 }
4069 } else
4070 iter->hash = hash;
4071
4072 ret = 0;
4073
4074 if (file->f_mode & FMODE_READ) {
4075 iter->pg = ftrace_pages_start;
4076
4077 ret = seq_open(file, &show_ftrace_seq_ops);
4078 if (!ret) {
4079 struct seq_file *m = file->private_data;
4080 m->private = iter;
4081 } else {
4082 /* Failed */
4083 free_ftrace_hash(iter->hash);
4084 trace_parser_put(&iter->parser);
4085 }
4086 } else
4087 file->private_data = iter;
4088
4089 out_unlock:
4090 mutex_unlock(&ops->func_hash->regex_lock);
4091
4092 out:
4093 if (ret) {
4094 kfree(iter);
4095 if (tr)
4096 trace_array_put(tr);
4097 }
4098
4099 return ret;
4100}
4101
4102static int
4103ftrace_filter_open(struct inode *inode, struct file *file)
4104{
4105 struct ftrace_ops *ops = inode->i_private;
4106
4107 /* Checks for tracefs lockdown */
4108 return ftrace_regex_open(ops,
4109 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4110 inode, file);
4111}
4112
4113static int
4114ftrace_notrace_open(struct inode *inode, struct file *file)
4115{
4116 struct ftrace_ops *ops = inode->i_private;
4117
4118 /* Checks for tracefs lockdown */
4119 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4120 inode, file);
4121}
4122
4123/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4124struct ftrace_glob {
4125 char *search;
4126 unsigned len;
4127 int type;
4128};
4129
4130/*
4131 * If symbols in an architecture don't correspond exactly to the user-visible
4132 * name of what they represent, it is possible to define this function to
4133 * perform the necessary adjustments.
4134*/
4135char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4136{
4137 return str;
4138}
4139
4140static int ftrace_match(char *str, struct ftrace_glob *g)
4141{
4142 int matched = 0;
4143 int slen;
4144
4145 str = arch_ftrace_match_adjust(str, g->search);
4146
4147 switch (g->type) {
4148 case MATCH_FULL:
4149 if (strcmp(str, g->search) == 0)
4150 matched = 1;
4151 break;
4152 case MATCH_FRONT_ONLY:
4153 if (strncmp(str, g->search, g->len) == 0)
4154 matched = 1;
4155 break;
4156 case MATCH_MIDDLE_ONLY:
4157 if (strstr(str, g->search))
4158 matched = 1;
4159 break;
4160 case MATCH_END_ONLY:
4161 slen = strlen(str);
4162 if (slen >= g->len &&
4163 memcmp(str + slen - g->len, g->search, g->len) == 0)
4164 matched = 1;
4165 break;
4166 case MATCH_GLOB:
4167 if (glob_match(g->search, str))
4168 matched = 1;
4169 break;
4170 }
4171
4172 return matched;
4173}
4174
4175static int
4176enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4177{
4178 struct ftrace_func_entry *entry;
4179 int ret = 0;
4180
4181 entry = ftrace_lookup_ip(hash, rec->ip);
4182 if (clear_filter) {
4183 /* Do nothing if it doesn't exist */
4184 if (!entry)
4185 return 0;
4186
4187 free_hash_entry(hash, entry);
4188 } else {
4189 /* Do nothing if it exists */
4190 if (entry)
4191 return 0;
4192 if (add_hash_entry(hash, rec->ip) == NULL)
4193 ret = -ENOMEM;
4194 }
4195 return ret;
4196}
4197
4198static int
4199add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4200 int clear_filter)
4201{
4202 long index = simple_strtoul(func_g->search, NULL, 0);
4203 struct ftrace_page *pg;
4204 struct dyn_ftrace *rec;
4205
4206 /* The index starts at 1 */
4207 if (--index < 0)
4208 return 0;
4209
4210 do_for_each_ftrace_rec(pg, rec) {
4211 if (pg->index <= index) {
4212 index -= pg->index;
4213 /* this is a double loop, break goes to the next page */
4214 break;
4215 }
4216 rec = &pg->records[index];
4217 enter_record(hash, rec, clear_filter);
4218 return 1;
4219 } while_for_each_ftrace_rec();
4220 return 0;
4221}
4222
4223#ifdef FTRACE_MCOUNT_MAX_OFFSET
4224static int lookup_ip(unsigned long ip, char **modname, char *str)
4225{
4226 unsigned long offset;
4227
4228 kallsyms_lookup(ip, NULL, &offset, modname, str);
4229 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4230 return -1;
4231 return 0;
4232}
4233#else
4234static int lookup_ip(unsigned long ip, char **modname, char *str)
4235{
4236 kallsyms_lookup(ip, NULL, NULL, modname, str);
4237 return 0;
4238}
4239#endif
4240
4241static int
4242ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4243 struct ftrace_glob *mod_g, int exclude_mod)
4244{
4245 char str[KSYM_SYMBOL_LEN];
4246 char *modname;
4247
4248 if (lookup_ip(rec->ip, &modname, str)) {
4249 /* This should only happen when a rec is disabled */
4250 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4251 !(rec->flags & FTRACE_FL_DISABLED));
4252 return 0;
4253 }
4254
4255 if (mod_g) {
4256 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4257
4258 /* blank module name to match all modules */
4259 if (!mod_g->len) {
4260 /* blank module globbing: modname xor exclude_mod */
4261 if (!exclude_mod != !modname)
4262 goto func_match;
4263 return 0;
4264 }
4265
4266 /*
4267 * exclude_mod is set to trace everything but the given
4268 * module. If it is set and the module matches, then
4269 * return 0. If it is not set, and the module doesn't match
4270 * also return 0. Otherwise, check the function to see if
4271 * that matches.
4272 */
4273 if (!mod_matches == !exclude_mod)
4274 return 0;
4275func_match:
4276 /* blank search means to match all funcs in the mod */
4277 if (!func_g->len)
4278 return 1;
4279 }
4280
4281 return ftrace_match(str, func_g);
4282}
4283
4284static int
4285match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4286{
4287 struct ftrace_page *pg;
4288 struct dyn_ftrace *rec;
4289 struct ftrace_glob func_g = { .type = MATCH_FULL };
4290 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4291 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4292 int exclude_mod = 0;
4293 int found = 0;
4294 int ret;
4295 int clear_filter = 0;
4296
4297 if (func) {
4298 func_g.type = filter_parse_regex(func, len, &func_g.search,
4299 &clear_filter);
4300 func_g.len = strlen(func_g.search);
4301 }
4302
4303 if (mod) {
4304 mod_g.type = filter_parse_regex(mod, strlen(mod),
4305 &mod_g.search, &exclude_mod);
4306 mod_g.len = strlen(mod_g.search);
4307 }
4308
4309 mutex_lock(&ftrace_lock);
4310
4311 if (unlikely(ftrace_disabled))
4312 goto out_unlock;
4313
4314 if (func_g.type == MATCH_INDEX) {
4315 found = add_rec_by_index(hash, &func_g, clear_filter);
4316 goto out_unlock;
4317 }
4318
4319 do_for_each_ftrace_rec(pg, rec) {
4320
4321 if (rec->flags & FTRACE_FL_DISABLED)
4322 continue;
4323
4324 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4325 ret = enter_record(hash, rec, clear_filter);
4326 if (ret < 0) {
4327 found = ret;
4328 goto out_unlock;
4329 }
4330 found = 1;
4331 }
4332 cond_resched();
4333 } while_for_each_ftrace_rec();
4334 out_unlock:
4335 mutex_unlock(&ftrace_lock);
4336
4337 return found;
4338}
4339
4340static int
4341ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4342{
4343 return match_records(hash, buff, len, NULL);
4344}
4345
4346static void ftrace_ops_update_code(struct ftrace_ops *ops,
4347 struct ftrace_ops_hash *old_hash)
4348{
4349 struct ftrace_ops *op;
4350
4351 if (!ftrace_enabled)
4352 return;
4353
4354 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4355 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4356 return;
4357 }
4358
4359 /*
4360 * If this is the shared global_ops filter, then we need to
4361 * check if there is another ops that shares it, is enabled.
4362 * If so, we still need to run the modify code.
4363 */
4364 if (ops->func_hash != &global_ops.local_hash)
4365 return;
4366
4367 do_for_each_ftrace_op(op, ftrace_ops_list) {
4368 if (op->func_hash == &global_ops.local_hash &&
4369 op->flags & FTRACE_OPS_FL_ENABLED) {
4370 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4371 /* Only need to do this once */
4372 return;
4373 }
4374 } while_for_each_ftrace_op(op);
4375}
4376
4377static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4378 struct ftrace_hash **orig_hash,
4379 struct ftrace_hash *hash,
4380 int enable)
4381{
4382 struct ftrace_ops_hash old_hash_ops;
4383 struct ftrace_hash *old_hash;
4384 int ret;
4385
4386 old_hash = *orig_hash;
4387 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4388 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4389 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4390 if (!ret) {
4391 ftrace_ops_update_code(ops, &old_hash_ops);
4392 free_ftrace_hash_rcu(old_hash);
4393 }
4394 return ret;
4395}
4396
4397static bool module_exists(const char *module)
4398{
4399 /* All modules have the symbol __this_module */
4400 static const char this_mod[] = "__this_module";
4401 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4402 unsigned long val;
4403 int n;
4404
4405 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4406
4407 if (n > sizeof(modname) - 1)
4408 return false;
4409
4410 val = module_kallsyms_lookup_name(modname);
4411 return val != 0;
4412}
4413
4414static int cache_mod(struct trace_array *tr,
4415 const char *func, char *module, int enable)
4416{
4417 struct ftrace_mod_load *ftrace_mod, *n;
4418 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4419 int ret;
4420
4421 mutex_lock(&ftrace_lock);
4422
4423 /* We do not cache inverse filters */
4424 if (func[0] == '!') {
4425 func++;
4426 ret = -EINVAL;
4427
4428 /* Look to remove this hash */
4429 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4430 if (strcmp(ftrace_mod->module, module) != 0)
4431 continue;
4432
4433 /* no func matches all */
4434 if (strcmp(func, "*") == 0 ||
4435 (ftrace_mod->func &&
4436 strcmp(ftrace_mod->func, func) == 0)) {
4437 ret = 0;
4438 free_ftrace_mod(ftrace_mod);
4439 continue;
4440 }
4441 }
4442 goto out;
4443 }
4444
4445 ret = -EINVAL;
4446 /* We only care about modules that have not been loaded yet */
4447 if (module_exists(module))
4448 goto out;
4449
4450 /* Save this string off, and execute it when the module is loaded */
4451 ret = ftrace_add_mod(tr, func, module, enable);
4452 out:
4453 mutex_unlock(&ftrace_lock);
4454
4455 return ret;
4456}
4457
4458static int
4459ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4460 int reset, int enable);
4461
4462#ifdef CONFIG_MODULES
4463static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4464 char *mod, bool enable)
4465{
4466 struct ftrace_mod_load *ftrace_mod, *n;
4467 struct ftrace_hash **orig_hash, *new_hash;
4468 LIST_HEAD(process_mods);
4469 char *func;
4470
4471 mutex_lock(&ops->func_hash->regex_lock);
4472
4473 if (enable)
4474 orig_hash = &ops->func_hash->filter_hash;
4475 else
4476 orig_hash = &ops->func_hash->notrace_hash;
4477
4478 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4479 *orig_hash);
4480 if (!new_hash)
4481 goto out; /* warn? */
4482
4483 mutex_lock(&ftrace_lock);
4484
4485 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4486
4487 if (strcmp(ftrace_mod->module, mod) != 0)
4488 continue;
4489
4490 if (ftrace_mod->func)
4491 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4492 else
4493 func = kstrdup("*", GFP_KERNEL);
4494
4495 if (!func) /* warn? */
4496 continue;
4497
4498 list_move(&ftrace_mod->list, &process_mods);
4499
4500 /* Use the newly allocated func, as it may be "*" */
4501 kfree(ftrace_mod->func);
4502 ftrace_mod->func = func;
4503 }
4504
4505 mutex_unlock(&ftrace_lock);
4506
4507 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4508
4509 func = ftrace_mod->func;
4510
4511 /* Grabs ftrace_lock, which is why we have this extra step */
4512 match_records(new_hash, func, strlen(func), mod);
4513 free_ftrace_mod(ftrace_mod);
4514 }
4515
4516 if (enable && list_empty(head))
4517 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4518
4519 mutex_lock(&ftrace_lock);
4520
4521 ftrace_hash_move_and_update_ops(ops, orig_hash,
4522 new_hash, enable);
4523 mutex_unlock(&ftrace_lock);
4524
4525 out:
4526 mutex_unlock(&ops->func_hash->regex_lock);
4527
4528 free_ftrace_hash(new_hash);
4529}
4530
4531static void process_cached_mods(const char *mod_name)
4532{
4533 struct trace_array *tr;
4534 char *mod;
4535
4536 mod = kstrdup(mod_name, GFP_KERNEL);
4537 if (!mod)
4538 return;
4539
4540 mutex_lock(&trace_types_lock);
4541 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4542 if (!list_empty(&tr->mod_trace))
4543 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4544 if (!list_empty(&tr->mod_notrace))
4545 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4546 }
4547 mutex_unlock(&trace_types_lock);
4548
4549 kfree(mod);
4550}
4551#endif
4552
4553/*
4554 * We register the module command as a template to show others how
4555 * to register the a command as well.
4556 */
4557
4558static int
4559ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4560 char *func_orig, char *cmd, char *module, int enable)
4561{
4562 char *func;
4563 int ret;
4564
4565 /* match_records() modifies func, and we need the original */
4566 func = kstrdup(func_orig, GFP_KERNEL);
4567 if (!func)
4568 return -ENOMEM;
4569
4570 /*
4571 * cmd == 'mod' because we only registered this func
4572 * for the 'mod' ftrace_func_command.
4573 * But if you register one func with multiple commands,
4574 * you can tell which command was used by the cmd
4575 * parameter.
4576 */
4577 ret = match_records(hash, func, strlen(func), module);
4578 kfree(func);
4579
4580 if (!ret)
4581 return cache_mod(tr, func_orig, module, enable);
4582 if (ret < 0)
4583 return ret;
4584 return 0;
4585}
4586
4587static struct ftrace_func_command ftrace_mod_cmd = {
4588 .name = "mod",
4589 .func = ftrace_mod_callback,
4590};
4591
4592static int __init ftrace_mod_cmd_init(void)
4593{
4594 return register_ftrace_command(&ftrace_mod_cmd);
4595}
4596core_initcall(ftrace_mod_cmd_init);
4597
4598static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4599 struct ftrace_ops *op, struct ftrace_regs *fregs)
4600{
4601 struct ftrace_probe_ops *probe_ops;
4602 struct ftrace_func_probe *probe;
4603
4604 probe = container_of(op, struct ftrace_func_probe, ops);
4605 probe_ops = probe->probe_ops;
4606
4607 /*
4608 * Disable preemption for these calls to prevent a RCU grace
4609 * period. This syncs the hash iteration and freeing of items
4610 * on the hash. rcu_read_lock is too dangerous here.
4611 */
4612 preempt_disable_notrace();
4613 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4614 preempt_enable_notrace();
4615}
4616
4617struct ftrace_func_map {
4618 struct ftrace_func_entry entry;
4619 void *data;
4620};
4621
4622struct ftrace_func_mapper {
4623 struct ftrace_hash hash;
4624};
4625
4626/**
4627 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4628 *
4629 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4630 */
4631struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4632{
4633 struct ftrace_hash *hash;
4634
4635 /*
4636 * The mapper is simply a ftrace_hash, but since the entries
4637 * in the hash are not ftrace_func_entry type, we define it
4638 * as a separate structure.
4639 */
4640 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4641 return (struct ftrace_func_mapper *)hash;
4642}
4643
4644/**
4645 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4646 * @mapper: The mapper that has the ip maps
4647 * @ip: the instruction pointer to find the data for
4648 *
4649 * Returns the data mapped to @ip if found otherwise NULL. The return
4650 * is actually the address of the mapper data pointer. The address is
4651 * returned for use cases where the data is no bigger than a long, and
4652 * the user can use the data pointer as its data instead of having to
4653 * allocate more memory for the reference.
4654 */
4655void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4656 unsigned long ip)
4657{
4658 struct ftrace_func_entry *entry;
4659 struct ftrace_func_map *map;
4660
4661 entry = ftrace_lookup_ip(&mapper->hash, ip);
4662 if (!entry)
4663 return NULL;
4664
4665 map = (struct ftrace_func_map *)entry;
4666 return &map->data;
4667}
4668
4669/**
4670 * ftrace_func_mapper_add_ip - Map some data to an ip
4671 * @mapper: The mapper that has the ip maps
4672 * @ip: The instruction pointer address to map @data to
4673 * @data: The data to map to @ip
4674 *
4675 * Returns 0 on success otherwise an error.
4676 */
4677int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4678 unsigned long ip, void *data)
4679{
4680 struct ftrace_func_entry *entry;
4681 struct ftrace_func_map *map;
4682
4683 entry = ftrace_lookup_ip(&mapper->hash, ip);
4684 if (entry)
4685 return -EBUSY;
4686
4687 map = kmalloc(sizeof(*map), GFP_KERNEL);
4688 if (!map)
4689 return -ENOMEM;
4690
4691 map->entry.ip = ip;
4692 map->data = data;
4693
4694 __add_hash_entry(&mapper->hash, &map->entry);
4695
4696 return 0;
4697}
4698
4699/**
4700 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4701 * @mapper: The mapper that has the ip maps
4702 * @ip: The instruction pointer address to remove the data from
4703 *
4704 * Returns the data if it is found, otherwise NULL.
4705 * Note, if the data pointer is used as the data itself, (see
4706 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4707 * if the data pointer was set to zero.
4708 */
4709void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4710 unsigned long ip)
4711{
4712 struct ftrace_func_entry *entry;
4713 struct ftrace_func_map *map;
4714 void *data;
4715
4716 entry = ftrace_lookup_ip(&mapper->hash, ip);
4717 if (!entry)
4718 return NULL;
4719
4720 map = (struct ftrace_func_map *)entry;
4721 data = map->data;
4722
4723 remove_hash_entry(&mapper->hash, entry);
4724 kfree(entry);
4725
4726 return data;
4727}
4728
4729/**
4730 * free_ftrace_func_mapper - free a mapping of ips and data
4731 * @mapper: The mapper that has the ip maps
4732 * @free_func: A function to be called on each data item.
4733 *
4734 * This is used to free the function mapper. The @free_func is optional
4735 * and can be used if the data needs to be freed as well.
4736 */
4737void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4738 ftrace_mapper_func free_func)
4739{
4740 struct ftrace_func_entry *entry;
4741 struct ftrace_func_map *map;
4742 struct hlist_head *hhd;
4743 int size, i;
4744
4745 if (!mapper)
4746 return;
4747
4748 if (free_func && mapper->hash.count) {
4749 size = 1 << mapper->hash.size_bits;
4750 for (i = 0; i < size; i++) {
4751 hhd = &mapper->hash.buckets[i];
4752 hlist_for_each_entry(entry, hhd, hlist) {
4753 map = (struct ftrace_func_map *)entry;
4754 free_func(map);
4755 }
4756 }
4757 }
4758 free_ftrace_hash(&mapper->hash);
4759}
4760
4761static void release_probe(struct ftrace_func_probe *probe)
4762{
4763 struct ftrace_probe_ops *probe_ops;
4764
4765 mutex_lock(&ftrace_lock);
4766
4767 WARN_ON(probe->ref <= 0);
4768
4769 /* Subtract the ref that was used to protect this instance */
4770 probe->ref--;
4771
4772 if (!probe->ref) {
4773 probe_ops = probe->probe_ops;
4774 /*
4775 * Sending zero as ip tells probe_ops to free
4776 * the probe->data itself
4777 */
4778 if (probe_ops->free)
4779 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4780 list_del(&probe->list);
4781 kfree(probe);
4782 }
4783 mutex_unlock(&ftrace_lock);
4784}
4785
4786static void acquire_probe_locked(struct ftrace_func_probe *probe)
4787{
4788 /*
4789 * Add one ref to keep it from being freed when releasing the
4790 * ftrace_lock mutex.
4791 */
4792 probe->ref++;
4793}
4794
4795int
4796register_ftrace_function_probe(char *glob, struct trace_array *tr,
4797 struct ftrace_probe_ops *probe_ops,
4798 void *data)
4799{
4800 struct ftrace_func_probe *probe = NULL, *iter;
4801 struct ftrace_func_entry *entry;
4802 struct ftrace_hash **orig_hash;
4803 struct ftrace_hash *old_hash;
4804 struct ftrace_hash *hash;
4805 int count = 0;
4806 int size;
4807 int ret;
4808 int i;
4809
4810 if (WARN_ON(!tr))
4811 return -EINVAL;
4812
4813 /* We do not support '!' for function probes */
4814 if (WARN_ON(glob[0] == '!'))
4815 return -EINVAL;
4816
4817
4818 mutex_lock(&ftrace_lock);
4819 /* Check if the probe_ops is already registered */
4820 list_for_each_entry(iter, &tr->func_probes, list) {
4821 if (iter->probe_ops == probe_ops) {
4822 probe = iter;
4823 break;
4824 }
4825 }
4826 if (!probe) {
4827 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4828 if (!probe) {
4829 mutex_unlock(&ftrace_lock);
4830 return -ENOMEM;
4831 }
4832 probe->probe_ops = probe_ops;
4833 probe->ops.func = function_trace_probe_call;
4834 probe->tr = tr;
4835 ftrace_ops_init(&probe->ops);
4836 list_add(&probe->list, &tr->func_probes);
4837 }
4838
4839 acquire_probe_locked(probe);
4840
4841 mutex_unlock(&ftrace_lock);
4842
4843 /*
4844 * Note, there's a small window here that the func_hash->filter_hash
4845 * may be NULL or empty. Need to be careful when reading the loop.
4846 */
4847 mutex_lock(&probe->ops.func_hash->regex_lock);
4848
4849 orig_hash = &probe->ops.func_hash->filter_hash;
4850 old_hash = *orig_hash;
4851 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4852
4853 if (!hash) {
4854 ret = -ENOMEM;
4855 goto out;
4856 }
4857
4858 ret = ftrace_match_records(hash, glob, strlen(glob));
4859
4860 /* Nothing found? */
4861 if (!ret)
4862 ret = -EINVAL;
4863
4864 if (ret < 0)
4865 goto out;
4866
4867 size = 1 << hash->size_bits;
4868 for (i = 0; i < size; i++) {
4869 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4870 if (ftrace_lookup_ip(old_hash, entry->ip))
4871 continue;
4872 /*
4873 * The caller might want to do something special
4874 * for each function we find. We call the callback
4875 * to give the caller an opportunity to do so.
4876 */
4877 if (probe_ops->init) {
4878 ret = probe_ops->init(probe_ops, tr,
4879 entry->ip, data,
4880 &probe->data);
4881 if (ret < 0) {
4882 if (probe_ops->free && count)
4883 probe_ops->free(probe_ops, tr,
4884 0, probe->data);
4885 probe->data = NULL;
4886 goto out;
4887 }
4888 }
4889 count++;
4890 }
4891 }
4892
4893 mutex_lock(&ftrace_lock);
4894
4895 if (!count) {
4896 /* Nothing was added? */
4897 ret = -EINVAL;
4898 goto out_unlock;
4899 }
4900
4901 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4902 hash, 1);
4903 if (ret < 0)
4904 goto err_unlock;
4905
4906 /* One ref for each new function traced */
4907 probe->ref += count;
4908
4909 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4910 ret = ftrace_startup(&probe->ops, 0);
4911
4912 out_unlock:
4913 mutex_unlock(&ftrace_lock);
4914
4915 if (!ret)
4916 ret = count;
4917 out:
4918 mutex_unlock(&probe->ops.func_hash->regex_lock);
4919 free_ftrace_hash(hash);
4920
4921 release_probe(probe);
4922
4923 return ret;
4924
4925 err_unlock:
4926 if (!probe_ops->free || !count)
4927 goto out_unlock;
4928
4929 /* Failed to do the move, need to call the free functions */
4930 for (i = 0; i < size; i++) {
4931 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4932 if (ftrace_lookup_ip(old_hash, entry->ip))
4933 continue;
4934 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4935 }
4936 }
4937 goto out_unlock;
4938}
4939
4940int
4941unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4942 struct ftrace_probe_ops *probe_ops)
4943{
4944 struct ftrace_func_probe *probe = NULL, *iter;
4945 struct ftrace_ops_hash old_hash_ops;
4946 struct ftrace_func_entry *entry;
4947 struct ftrace_glob func_g;
4948 struct ftrace_hash **orig_hash;
4949 struct ftrace_hash *old_hash;
4950 struct ftrace_hash *hash = NULL;
4951 struct hlist_node *tmp;
4952 struct hlist_head hhd;
4953 char str[KSYM_SYMBOL_LEN];
4954 int count = 0;
4955 int i, ret = -ENODEV;
4956 int size;
4957
4958 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4959 func_g.search = NULL;
4960 else {
4961 int not;
4962
4963 func_g.type = filter_parse_regex(glob, strlen(glob),
4964 &func_g.search, ¬);
4965 func_g.len = strlen(func_g.search);
4966
4967 /* we do not support '!' for function probes */
4968 if (WARN_ON(not))
4969 return -EINVAL;
4970 }
4971
4972 mutex_lock(&ftrace_lock);
4973 /* Check if the probe_ops is already registered */
4974 list_for_each_entry(iter, &tr->func_probes, list) {
4975 if (iter->probe_ops == probe_ops) {
4976 probe = iter;
4977 break;
4978 }
4979 }
4980 if (!probe)
4981 goto err_unlock_ftrace;
4982
4983 ret = -EINVAL;
4984 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4985 goto err_unlock_ftrace;
4986
4987 acquire_probe_locked(probe);
4988
4989 mutex_unlock(&ftrace_lock);
4990
4991 mutex_lock(&probe->ops.func_hash->regex_lock);
4992
4993 orig_hash = &probe->ops.func_hash->filter_hash;
4994 old_hash = *orig_hash;
4995
4996 if (ftrace_hash_empty(old_hash))
4997 goto out_unlock;
4998
4999 old_hash_ops.filter_hash = old_hash;
5000 /* Probes only have filters */
5001 old_hash_ops.notrace_hash = NULL;
5002
5003 ret = -ENOMEM;
5004 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5005 if (!hash)
5006 goto out_unlock;
5007
5008 INIT_HLIST_HEAD(&hhd);
5009
5010 size = 1 << hash->size_bits;
5011 for (i = 0; i < size; i++) {
5012 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5013
5014 if (func_g.search) {
5015 kallsyms_lookup(entry->ip, NULL, NULL,
5016 NULL, str);
5017 if (!ftrace_match(str, &func_g))
5018 continue;
5019 }
5020 count++;
5021 remove_hash_entry(hash, entry);
5022 hlist_add_head(&entry->hlist, &hhd);
5023 }
5024 }
5025
5026 /* Nothing found? */
5027 if (!count) {
5028 ret = -EINVAL;
5029 goto out_unlock;
5030 }
5031
5032 mutex_lock(&ftrace_lock);
5033
5034 WARN_ON(probe->ref < count);
5035
5036 probe->ref -= count;
5037
5038 if (ftrace_hash_empty(hash))
5039 ftrace_shutdown(&probe->ops, 0);
5040
5041 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5042 hash, 1);
5043
5044 /* still need to update the function call sites */
5045 if (ftrace_enabled && !ftrace_hash_empty(hash))
5046 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5047 &old_hash_ops);
5048 synchronize_rcu();
5049
5050 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5051 hlist_del(&entry->hlist);
5052 if (probe_ops->free)
5053 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5054 kfree(entry);
5055 }
5056 mutex_unlock(&ftrace_lock);
5057
5058 out_unlock:
5059 mutex_unlock(&probe->ops.func_hash->regex_lock);
5060 free_ftrace_hash(hash);
5061
5062 release_probe(probe);
5063
5064 return ret;
5065
5066 err_unlock_ftrace:
5067 mutex_unlock(&ftrace_lock);
5068 return ret;
5069}
5070
5071void clear_ftrace_function_probes(struct trace_array *tr)
5072{
5073 struct ftrace_func_probe *probe, *n;
5074
5075 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5076 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5077}
5078
5079static LIST_HEAD(ftrace_commands);
5080static DEFINE_MUTEX(ftrace_cmd_mutex);
5081
5082/*
5083 * Currently we only register ftrace commands from __init, so mark this
5084 * __init too.
5085 */
5086__init int register_ftrace_command(struct ftrace_func_command *cmd)
5087{
5088 struct ftrace_func_command *p;
5089 int ret = 0;
5090
5091 mutex_lock(&ftrace_cmd_mutex);
5092 list_for_each_entry(p, &ftrace_commands, list) {
5093 if (strcmp(cmd->name, p->name) == 0) {
5094 ret = -EBUSY;
5095 goto out_unlock;
5096 }
5097 }
5098 list_add(&cmd->list, &ftrace_commands);
5099 out_unlock:
5100 mutex_unlock(&ftrace_cmd_mutex);
5101
5102 return ret;
5103}
5104
5105/*
5106 * Currently we only unregister ftrace commands from __init, so mark
5107 * this __init too.
5108 */
5109__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5110{
5111 struct ftrace_func_command *p, *n;
5112 int ret = -ENODEV;
5113
5114 mutex_lock(&ftrace_cmd_mutex);
5115 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5116 if (strcmp(cmd->name, p->name) == 0) {
5117 ret = 0;
5118 list_del_init(&p->list);
5119 goto out_unlock;
5120 }
5121 }
5122 out_unlock:
5123 mutex_unlock(&ftrace_cmd_mutex);
5124
5125 return ret;
5126}
5127
5128static int ftrace_process_regex(struct ftrace_iterator *iter,
5129 char *buff, int len, int enable)
5130{
5131 struct ftrace_hash *hash = iter->hash;
5132 struct trace_array *tr = iter->ops->private;
5133 char *func, *command, *next = buff;
5134 struct ftrace_func_command *p;
5135 int ret = -EINVAL;
5136
5137 func = strsep(&next, ":");
5138
5139 if (!next) {
5140 ret = ftrace_match_records(hash, func, len);
5141 if (!ret)
5142 ret = -EINVAL;
5143 if (ret < 0)
5144 return ret;
5145 return 0;
5146 }
5147
5148 /* command found */
5149
5150 command = strsep(&next, ":");
5151
5152 mutex_lock(&ftrace_cmd_mutex);
5153 list_for_each_entry(p, &ftrace_commands, list) {
5154 if (strcmp(p->name, command) == 0) {
5155 ret = p->func(tr, hash, func, command, next, enable);
5156 goto out_unlock;
5157 }
5158 }
5159 out_unlock:
5160 mutex_unlock(&ftrace_cmd_mutex);
5161
5162 return ret;
5163}
5164
5165static ssize_t
5166ftrace_regex_write(struct file *file, const char __user *ubuf,
5167 size_t cnt, loff_t *ppos, int enable)
5168{
5169 struct ftrace_iterator *iter;
5170 struct trace_parser *parser;
5171 ssize_t ret, read;
5172
5173 if (!cnt)
5174 return 0;
5175
5176 if (file->f_mode & FMODE_READ) {
5177 struct seq_file *m = file->private_data;
5178 iter = m->private;
5179 } else
5180 iter = file->private_data;
5181
5182 if (unlikely(ftrace_disabled))
5183 return -ENODEV;
5184
5185 /* iter->hash is a local copy, so we don't need regex_lock */
5186
5187 parser = &iter->parser;
5188 read = trace_get_user(parser, ubuf, cnt, ppos);
5189
5190 if (read >= 0 && trace_parser_loaded(parser) &&
5191 !trace_parser_cont(parser)) {
5192 ret = ftrace_process_regex(iter, parser->buffer,
5193 parser->idx, enable);
5194 trace_parser_clear(parser);
5195 if (ret < 0)
5196 goto out;
5197 }
5198
5199 ret = read;
5200 out:
5201 return ret;
5202}
5203
5204ssize_t
5205ftrace_filter_write(struct file *file, const char __user *ubuf,
5206 size_t cnt, loff_t *ppos)
5207{
5208 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5209}
5210
5211ssize_t
5212ftrace_notrace_write(struct file *file, const char __user *ubuf,
5213 size_t cnt, loff_t *ppos)
5214{
5215 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5216}
5217
5218static int
5219__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5220{
5221 struct ftrace_func_entry *entry;
5222
5223 ip = ftrace_location(ip);
5224 if (!ip)
5225 return -EINVAL;
5226
5227 if (remove) {
5228 entry = ftrace_lookup_ip(hash, ip);
5229 if (!entry)
5230 return -ENOENT;
5231 free_hash_entry(hash, entry);
5232 return 0;
5233 }
5234
5235 entry = add_hash_entry(hash, ip);
5236 return entry ? 0 : -ENOMEM;
5237}
5238
5239static int
5240ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5241 unsigned int cnt, int remove)
5242{
5243 unsigned int i;
5244 int err;
5245
5246 for (i = 0; i < cnt; i++) {
5247 err = __ftrace_match_addr(hash, ips[i], remove);
5248 if (err) {
5249 /*
5250 * This expects the @hash is a temporary hash and if this
5251 * fails the caller must free the @hash.
5252 */
5253 return err;
5254 }
5255 }
5256 return 0;
5257}
5258
5259static int
5260ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5261 unsigned long *ips, unsigned int cnt,
5262 int remove, int reset, int enable)
5263{
5264 struct ftrace_hash **orig_hash;
5265 struct ftrace_hash *hash;
5266 int ret;
5267
5268 if (unlikely(ftrace_disabled))
5269 return -ENODEV;
5270
5271 mutex_lock(&ops->func_hash->regex_lock);
5272
5273 if (enable)
5274 orig_hash = &ops->func_hash->filter_hash;
5275 else
5276 orig_hash = &ops->func_hash->notrace_hash;
5277
5278 if (reset)
5279 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5280 else
5281 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5282
5283 if (!hash) {
5284 ret = -ENOMEM;
5285 goto out_regex_unlock;
5286 }
5287
5288 if (buf && !ftrace_match_records(hash, buf, len)) {
5289 ret = -EINVAL;
5290 goto out_regex_unlock;
5291 }
5292 if (ips) {
5293 ret = ftrace_match_addr(hash, ips, cnt, remove);
5294 if (ret < 0)
5295 goto out_regex_unlock;
5296 }
5297
5298 mutex_lock(&ftrace_lock);
5299 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5300 mutex_unlock(&ftrace_lock);
5301
5302 out_regex_unlock:
5303 mutex_unlock(&ops->func_hash->regex_lock);
5304
5305 free_ftrace_hash(hash);
5306 return ret;
5307}
5308
5309static int
5310ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5311 int remove, int reset, int enable)
5312{
5313 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5314}
5315
5316#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5317
5318struct ftrace_direct_func {
5319 struct list_head next;
5320 unsigned long addr;
5321 int count;
5322};
5323
5324static LIST_HEAD(ftrace_direct_funcs);
5325
5326static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5327
5328/*
5329 * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
5330 * call will be jumped from ftrace_regs_caller. Only if the architecture does
5331 * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
5332 * jumps from ftrace_caller for multiple ftrace_ops.
5333 */
5334#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
5335#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5336#else
5337#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5338#endif
5339
5340static int check_direct_multi(struct ftrace_ops *ops)
5341{
5342 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5343 return -EINVAL;
5344 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5345 return -EINVAL;
5346 return 0;
5347}
5348
5349static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5350{
5351 struct ftrace_func_entry *entry, *del;
5352 int size, i;
5353
5354 size = 1 << hash->size_bits;
5355 for (i = 0; i < size; i++) {
5356 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5357 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5358 if (del && del->direct == addr) {
5359 remove_hash_entry(direct_functions, del);
5360 kfree(del);
5361 }
5362 }
5363 }
5364}
5365
5366/**
5367 * register_ftrace_direct - Call a custom trampoline directly
5368 * for multiple functions registered in @ops
5369 * @ops: The address of the struct ftrace_ops object
5370 * @addr: The address of the trampoline to call at @ops functions
5371 *
5372 * This is used to connect a direct calls to @addr from the nop locations
5373 * of the functions registered in @ops (with by ftrace_set_filter_ip
5374 * function).
5375 *
5376 * The location that it calls (@addr) must be able to handle a direct call,
5377 * and save the parameters of the function being traced, and restore them
5378 * (or inject new ones if needed), before returning.
5379 *
5380 * Returns:
5381 * 0 on success
5382 * -EINVAL - The @ops object was already registered with this call or
5383 * when there are no functions in @ops object.
5384 * -EBUSY - Another direct function is already attached (there can be only one)
5385 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5386 * -ENOMEM - There was an allocation failure.
5387 */
5388int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5389{
5390 struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL;
5391 struct ftrace_func_entry *entry, *new;
5392 int err = -EBUSY, size, i;
5393
5394 if (ops->func || ops->trampoline)
5395 return -EINVAL;
5396 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5397 return -EINVAL;
5398 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5399 return -EINVAL;
5400
5401 hash = ops->func_hash->filter_hash;
5402 if (ftrace_hash_empty(hash))
5403 return -EINVAL;
5404
5405 mutex_lock(&direct_mutex);
5406
5407 /* Make sure requested entries are not already registered.. */
5408 size = 1 << hash->size_bits;
5409 for (i = 0; i < size; i++) {
5410 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5411 if (ftrace_find_rec_direct(entry->ip))
5412 goto out_unlock;
5413 }
5414 }
5415
5416 err = -ENOMEM;
5417
5418 /* Make a copy hash to place the new and the old entries in */
5419 size = hash->count + direct_functions->count;
5420 if (size > 32)
5421 size = 32;
5422 new_hash = alloc_ftrace_hash(fls(size));
5423 if (!new_hash)
5424 goto out_unlock;
5425
5426 /* Now copy over the existing direct entries */
5427 size = 1 << direct_functions->size_bits;
5428 for (i = 0; i < size; i++) {
5429 hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) {
5430 new = add_hash_entry(new_hash, entry->ip);
5431 if (!new)
5432 goto out_unlock;
5433 new->direct = entry->direct;
5434 }
5435 }
5436
5437 /* ... and add the new entries */
5438 size = 1 << hash->size_bits;
5439 for (i = 0; i < size; i++) {
5440 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5441 new = add_hash_entry(new_hash, entry->ip);
5442 if (!new)
5443 goto out_unlock;
5444 /* Update both the copy and the hash entry */
5445 new->direct = addr;
5446 entry->direct = addr;
5447 }
5448 }
5449
5450 free_hash = direct_functions;
5451 rcu_assign_pointer(direct_functions, new_hash);
5452 new_hash = NULL;
5453
5454 ops->func = call_direct_funcs;
5455 ops->flags = MULTI_FLAGS;
5456 ops->trampoline = FTRACE_REGS_ADDR;
5457 ops->direct_call = addr;
5458
5459 err = register_ftrace_function_nolock(ops);
5460
5461 out_unlock:
5462 mutex_unlock(&direct_mutex);
5463
5464 if (free_hash && free_hash != EMPTY_HASH) {
5465 synchronize_rcu_tasks();
5466 free_ftrace_hash(free_hash);
5467 }
5468
5469 if (new_hash)
5470 free_ftrace_hash(new_hash);
5471
5472 return err;
5473}
5474EXPORT_SYMBOL_GPL(register_ftrace_direct);
5475
5476/**
5477 * unregister_ftrace_direct - Remove calls to custom trampoline
5478 * previously registered by register_ftrace_direct for @ops object.
5479 * @ops: The address of the struct ftrace_ops object
5480 *
5481 * This is used to remove a direct calls to @addr from the nop locations
5482 * of the functions registered in @ops (with by ftrace_set_filter_ip
5483 * function).
5484 *
5485 * Returns:
5486 * 0 on success
5487 * -EINVAL - The @ops object was not properly registered.
5488 */
5489int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5490 bool free_filters)
5491{
5492 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5493 int err;
5494
5495 if (check_direct_multi(ops))
5496 return -EINVAL;
5497 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5498 return -EINVAL;
5499
5500 mutex_lock(&direct_mutex);
5501 err = unregister_ftrace_function(ops);
5502 remove_direct_functions_hash(hash, addr);
5503 mutex_unlock(&direct_mutex);
5504
5505 /* cleanup for possible another register call */
5506 ops->func = NULL;
5507 ops->trampoline = 0;
5508
5509 if (free_filters)
5510 ftrace_free_filter(ops);
5511 return err;
5512}
5513EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5514
5515static int
5516__modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5517{
5518 struct ftrace_hash *hash;
5519 struct ftrace_func_entry *entry, *iter;
5520 static struct ftrace_ops tmp_ops = {
5521 .func = ftrace_stub,
5522 .flags = FTRACE_OPS_FL_STUB,
5523 };
5524 int i, size;
5525 int err;
5526
5527 lockdep_assert_held_once(&direct_mutex);
5528
5529 /* Enable the tmp_ops to have the same functions as the direct ops */
5530 ftrace_ops_init(&tmp_ops);
5531 tmp_ops.func_hash = ops->func_hash;
5532 tmp_ops.direct_call = addr;
5533
5534 err = register_ftrace_function_nolock(&tmp_ops);
5535 if (err)
5536 return err;
5537
5538 /*
5539 * Now the ftrace_ops_list_func() is called to do the direct callers.
5540 * We can safely change the direct functions attached to each entry.
5541 */
5542 mutex_lock(&ftrace_lock);
5543
5544 hash = ops->func_hash->filter_hash;
5545 size = 1 << hash->size_bits;
5546 for (i = 0; i < size; i++) {
5547 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5548 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5549 if (!entry)
5550 continue;
5551 entry->direct = addr;
5552 }
5553 }
5554 /* Prevent store tearing if a trampoline concurrently accesses the value */
5555 WRITE_ONCE(ops->direct_call, addr);
5556
5557 mutex_unlock(&ftrace_lock);
5558
5559 /* Removing the tmp_ops will add the updated direct callers to the functions */
5560 unregister_ftrace_function(&tmp_ops);
5561
5562 return err;
5563}
5564
5565/**
5566 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5567 * to call something else
5568 * @ops: The address of the struct ftrace_ops object
5569 * @addr: The address of the new trampoline to call at @ops functions
5570 *
5571 * This is used to unregister currently registered direct caller and
5572 * register new one @addr on functions registered in @ops object.
5573 *
5574 * Note there's window between ftrace_shutdown and ftrace_startup calls
5575 * where there will be no callbacks called.
5576 *
5577 * Caller should already have direct_mutex locked, so we don't lock
5578 * direct_mutex here.
5579 *
5580 * Returns: zero on success. Non zero on error, which includes:
5581 * -EINVAL - The @ops object was not properly registered.
5582 */
5583int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5584{
5585 if (check_direct_multi(ops))
5586 return -EINVAL;
5587 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5588 return -EINVAL;
5589
5590 return __modify_ftrace_direct(ops, addr);
5591}
5592EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5593
5594/**
5595 * modify_ftrace_direct - Modify an existing direct 'multi' call
5596 * to call something else
5597 * @ops: The address of the struct ftrace_ops object
5598 * @addr: The address of the new trampoline to call at @ops functions
5599 *
5600 * This is used to unregister currently registered direct caller and
5601 * register new one @addr on functions registered in @ops object.
5602 *
5603 * Note there's window between ftrace_shutdown and ftrace_startup calls
5604 * where there will be no callbacks called.
5605 *
5606 * Returns: zero on success. Non zero on error, which includes:
5607 * -EINVAL - The @ops object was not properly registered.
5608 */
5609int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5610{
5611 int err;
5612
5613 if (check_direct_multi(ops))
5614 return -EINVAL;
5615 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5616 return -EINVAL;
5617
5618 mutex_lock(&direct_mutex);
5619 err = __modify_ftrace_direct(ops, addr);
5620 mutex_unlock(&direct_mutex);
5621 return err;
5622}
5623EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5624#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5625
5626/**
5627 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5628 * @ops - the ops to set the filter with
5629 * @ip - the address to add to or remove from the filter.
5630 * @remove - non zero to remove the ip from the filter
5631 * @reset - non zero to reset all filters before applying this filter.
5632 *
5633 * Filters denote which functions should be enabled when tracing is enabled
5634 * If @ip is NULL, it fails to update filter.
5635 *
5636 * This can allocate memory which must be freed before @ops can be freed,
5637 * either by removing each filtered addr or by using
5638 * ftrace_free_filter(@ops).
5639 */
5640int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5641 int remove, int reset)
5642{
5643 ftrace_ops_init(ops);
5644 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5645}
5646EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5647
5648/**
5649 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5650 * @ops - the ops to set the filter with
5651 * @ips - the array of addresses to add to or remove from the filter.
5652 * @cnt - the number of addresses in @ips
5653 * @remove - non zero to remove ips from the filter
5654 * @reset - non zero to reset all filters before applying this filter.
5655 *
5656 * Filters denote which functions should be enabled when tracing is enabled
5657 * If @ips array or any ip specified within is NULL , it fails to update filter.
5658 *
5659 * This can allocate memory which must be freed before @ops can be freed,
5660 * either by removing each filtered addr or by using
5661 * ftrace_free_filter(@ops).
5662*/
5663int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5664 unsigned int cnt, int remove, int reset)
5665{
5666 ftrace_ops_init(ops);
5667 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5668}
5669EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5670
5671/**
5672 * ftrace_ops_set_global_filter - setup ops to use global filters
5673 * @ops - the ops which will use the global filters
5674 *
5675 * ftrace users who need global function trace filtering should call this.
5676 * It can set the global filter only if ops were not initialized before.
5677 */
5678void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5679{
5680 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5681 return;
5682
5683 ftrace_ops_init(ops);
5684 ops->func_hash = &global_ops.local_hash;
5685}
5686EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5687
5688static int
5689ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5690 int reset, int enable)
5691{
5692 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5693}
5694
5695/**
5696 * ftrace_set_filter - set a function to filter on in ftrace
5697 * @ops - the ops to set the filter with
5698 * @buf - the string that holds the function filter text.
5699 * @len - the length of the string.
5700 * @reset - non zero to reset all filters before applying this filter.
5701 *
5702 * Filters denote which functions should be enabled when tracing is enabled.
5703 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5704 *
5705 * This can allocate memory which must be freed before @ops can be freed,
5706 * either by removing each filtered addr or by using
5707 * ftrace_free_filter(@ops).
5708 */
5709int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5710 int len, int reset)
5711{
5712 ftrace_ops_init(ops);
5713 return ftrace_set_regex(ops, buf, len, reset, 1);
5714}
5715EXPORT_SYMBOL_GPL(ftrace_set_filter);
5716
5717/**
5718 * ftrace_set_notrace - set a function to not trace in ftrace
5719 * @ops - the ops to set the notrace filter with
5720 * @buf - the string that holds the function notrace text.
5721 * @len - the length of the string.
5722 * @reset - non zero to reset all filters before applying this filter.
5723 *
5724 * Notrace Filters denote which functions should not be enabled when tracing
5725 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5726 * for tracing.
5727 *
5728 * This can allocate memory which must be freed before @ops can be freed,
5729 * either by removing each filtered addr or by using
5730 * ftrace_free_filter(@ops).
5731 */
5732int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5733 int len, int reset)
5734{
5735 ftrace_ops_init(ops);
5736 return ftrace_set_regex(ops, buf, len, reset, 0);
5737}
5738EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5739/**
5740 * ftrace_set_global_filter - set a function to filter on with global tracers
5741 * @buf - the string that holds the function filter text.
5742 * @len - the length of the string.
5743 * @reset - non zero to reset all filters before applying this filter.
5744 *
5745 * Filters denote which functions should be enabled when tracing is enabled.
5746 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5747 */
5748void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5749{
5750 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5751}
5752EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5753
5754/**
5755 * ftrace_set_global_notrace - set a function to not trace with global tracers
5756 * @buf - the string that holds the function notrace text.
5757 * @len - the length of the string.
5758 * @reset - non zero to reset all filters before applying this filter.
5759 *
5760 * Notrace Filters denote which functions should not be enabled when tracing
5761 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5762 * for tracing.
5763 */
5764void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5765{
5766 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5767}
5768EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5769
5770/*
5771 * command line interface to allow users to set filters on boot up.
5772 */
5773#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5774static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5775static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5776
5777/* Used by function selftest to not test if filter is set */
5778bool ftrace_filter_param __initdata;
5779
5780static int __init set_ftrace_notrace(char *str)
5781{
5782 ftrace_filter_param = true;
5783 strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5784 return 1;
5785}
5786__setup("ftrace_notrace=", set_ftrace_notrace);
5787
5788static int __init set_ftrace_filter(char *str)
5789{
5790 ftrace_filter_param = true;
5791 strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5792 return 1;
5793}
5794__setup("ftrace_filter=", set_ftrace_filter);
5795
5796#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5797static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5798static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5799static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5800
5801static int __init set_graph_function(char *str)
5802{
5803 strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5804 return 1;
5805}
5806__setup("ftrace_graph_filter=", set_graph_function);
5807
5808static int __init set_graph_notrace_function(char *str)
5809{
5810 strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5811 return 1;
5812}
5813__setup("ftrace_graph_notrace=", set_graph_notrace_function);
5814
5815static int __init set_graph_max_depth_function(char *str)
5816{
5817 if (!str)
5818 return 0;
5819 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5820 return 1;
5821}
5822__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5823
5824static void __init set_ftrace_early_graph(char *buf, int enable)
5825{
5826 int ret;
5827 char *func;
5828 struct ftrace_hash *hash;
5829
5830 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5831 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5832 return;
5833
5834 while (buf) {
5835 func = strsep(&buf, ",");
5836 /* we allow only one expression at a time */
5837 ret = ftrace_graph_set_hash(hash, func);
5838 if (ret)
5839 printk(KERN_DEBUG "ftrace: function %s not "
5840 "traceable\n", func);
5841 }
5842
5843 if (enable)
5844 ftrace_graph_hash = hash;
5845 else
5846 ftrace_graph_notrace_hash = hash;
5847}
5848#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5849
5850void __init
5851ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5852{
5853 char *func;
5854
5855 ftrace_ops_init(ops);
5856
5857 while (buf) {
5858 func = strsep(&buf, ",");
5859 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5860 }
5861}
5862
5863static void __init set_ftrace_early_filters(void)
5864{
5865 if (ftrace_filter_buf[0])
5866 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5867 if (ftrace_notrace_buf[0])
5868 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5869#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5870 if (ftrace_graph_buf[0])
5871 set_ftrace_early_graph(ftrace_graph_buf, 1);
5872 if (ftrace_graph_notrace_buf[0])
5873 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5874#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5875}
5876
5877int ftrace_regex_release(struct inode *inode, struct file *file)
5878{
5879 struct seq_file *m = (struct seq_file *)file->private_data;
5880 struct ftrace_iterator *iter;
5881 struct ftrace_hash **orig_hash;
5882 struct trace_parser *parser;
5883 int filter_hash;
5884
5885 if (file->f_mode & FMODE_READ) {
5886 iter = m->private;
5887 seq_release(inode, file);
5888 } else
5889 iter = file->private_data;
5890
5891 parser = &iter->parser;
5892 if (trace_parser_loaded(parser)) {
5893 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5894
5895 ftrace_process_regex(iter, parser->buffer,
5896 parser->idx, enable);
5897 }
5898
5899 trace_parser_put(parser);
5900
5901 mutex_lock(&iter->ops->func_hash->regex_lock);
5902
5903 if (file->f_mode & FMODE_WRITE) {
5904 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5905
5906 if (filter_hash) {
5907 orig_hash = &iter->ops->func_hash->filter_hash;
5908 if (iter->tr) {
5909 if (list_empty(&iter->tr->mod_trace))
5910 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5911 else
5912 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5913 }
5914 } else
5915 orig_hash = &iter->ops->func_hash->notrace_hash;
5916
5917 mutex_lock(&ftrace_lock);
5918 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5919 iter->hash, filter_hash);
5920 mutex_unlock(&ftrace_lock);
5921 } else {
5922 /* For read only, the hash is the ops hash */
5923 iter->hash = NULL;
5924 }
5925
5926 mutex_unlock(&iter->ops->func_hash->regex_lock);
5927 free_ftrace_hash(iter->hash);
5928 if (iter->tr)
5929 trace_array_put(iter->tr);
5930 kfree(iter);
5931
5932 return 0;
5933}
5934
5935static const struct file_operations ftrace_avail_fops = {
5936 .open = ftrace_avail_open,
5937 .read = seq_read,
5938 .llseek = seq_lseek,
5939 .release = seq_release_private,
5940};
5941
5942static const struct file_operations ftrace_enabled_fops = {
5943 .open = ftrace_enabled_open,
5944 .read = seq_read,
5945 .llseek = seq_lseek,
5946 .release = seq_release_private,
5947};
5948
5949static const struct file_operations ftrace_touched_fops = {
5950 .open = ftrace_touched_open,
5951 .read = seq_read,
5952 .llseek = seq_lseek,
5953 .release = seq_release_private,
5954};
5955
5956static const struct file_operations ftrace_avail_addrs_fops = {
5957 .open = ftrace_avail_addrs_open,
5958 .read = seq_read,
5959 .llseek = seq_lseek,
5960 .release = seq_release_private,
5961};
5962
5963static const struct file_operations ftrace_filter_fops = {
5964 .open = ftrace_filter_open,
5965 .read = seq_read,
5966 .write = ftrace_filter_write,
5967 .llseek = tracing_lseek,
5968 .release = ftrace_regex_release,
5969};
5970
5971static const struct file_operations ftrace_notrace_fops = {
5972 .open = ftrace_notrace_open,
5973 .read = seq_read,
5974 .write = ftrace_notrace_write,
5975 .llseek = tracing_lseek,
5976 .release = ftrace_regex_release,
5977};
5978
5979#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5980
5981static DEFINE_MUTEX(graph_lock);
5982
5983struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5984struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5985
5986enum graph_filter_type {
5987 GRAPH_FILTER_NOTRACE = 0,
5988 GRAPH_FILTER_FUNCTION,
5989};
5990
5991#define FTRACE_GRAPH_EMPTY ((void *)1)
5992
5993struct ftrace_graph_data {
5994 struct ftrace_hash *hash;
5995 struct ftrace_func_entry *entry;
5996 int idx; /* for hash table iteration */
5997 enum graph_filter_type type;
5998 struct ftrace_hash *new_hash;
5999 const struct seq_operations *seq_ops;
6000 struct trace_parser parser;
6001};
6002
6003static void *
6004__g_next(struct seq_file *m, loff_t *pos)
6005{
6006 struct ftrace_graph_data *fgd = m->private;
6007 struct ftrace_func_entry *entry = fgd->entry;
6008 struct hlist_head *head;
6009 int i, idx = fgd->idx;
6010
6011 if (*pos >= fgd->hash->count)
6012 return NULL;
6013
6014 if (entry) {
6015 hlist_for_each_entry_continue(entry, hlist) {
6016 fgd->entry = entry;
6017 return entry;
6018 }
6019
6020 idx++;
6021 }
6022
6023 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6024 head = &fgd->hash->buckets[i];
6025 hlist_for_each_entry(entry, head, hlist) {
6026 fgd->entry = entry;
6027 fgd->idx = i;
6028 return entry;
6029 }
6030 }
6031 return NULL;
6032}
6033
6034static void *
6035g_next(struct seq_file *m, void *v, loff_t *pos)
6036{
6037 (*pos)++;
6038 return __g_next(m, pos);
6039}
6040
6041static void *g_start(struct seq_file *m, loff_t *pos)
6042{
6043 struct ftrace_graph_data *fgd = m->private;
6044
6045 mutex_lock(&graph_lock);
6046
6047 if (fgd->type == GRAPH_FILTER_FUNCTION)
6048 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6049 lockdep_is_held(&graph_lock));
6050 else
6051 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6052 lockdep_is_held(&graph_lock));
6053
6054 /* Nothing, tell g_show to print all functions are enabled */
6055 if (ftrace_hash_empty(fgd->hash) && !*pos)
6056 return FTRACE_GRAPH_EMPTY;
6057
6058 fgd->idx = 0;
6059 fgd->entry = NULL;
6060 return __g_next(m, pos);
6061}
6062
6063static void g_stop(struct seq_file *m, void *p)
6064{
6065 mutex_unlock(&graph_lock);
6066}
6067
6068static int g_show(struct seq_file *m, void *v)
6069{
6070 struct ftrace_func_entry *entry = v;
6071
6072 if (!entry)
6073 return 0;
6074
6075 if (entry == FTRACE_GRAPH_EMPTY) {
6076 struct ftrace_graph_data *fgd = m->private;
6077
6078 if (fgd->type == GRAPH_FILTER_FUNCTION)
6079 seq_puts(m, "#### all functions enabled ####\n");
6080 else
6081 seq_puts(m, "#### no functions disabled ####\n");
6082 return 0;
6083 }
6084
6085 seq_printf(m, "%ps\n", (void *)entry->ip);
6086
6087 return 0;
6088}
6089
6090static const struct seq_operations ftrace_graph_seq_ops = {
6091 .start = g_start,
6092 .next = g_next,
6093 .stop = g_stop,
6094 .show = g_show,
6095};
6096
6097static int
6098__ftrace_graph_open(struct inode *inode, struct file *file,
6099 struct ftrace_graph_data *fgd)
6100{
6101 int ret;
6102 struct ftrace_hash *new_hash = NULL;
6103
6104 ret = security_locked_down(LOCKDOWN_TRACEFS);
6105 if (ret)
6106 return ret;
6107
6108 if (file->f_mode & FMODE_WRITE) {
6109 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6110
6111 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6112 return -ENOMEM;
6113
6114 if (file->f_flags & O_TRUNC)
6115 new_hash = alloc_ftrace_hash(size_bits);
6116 else
6117 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6118 fgd->hash);
6119 if (!new_hash) {
6120 ret = -ENOMEM;
6121 goto out;
6122 }
6123 }
6124
6125 if (file->f_mode & FMODE_READ) {
6126 ret = seq_open(file, &ftrace_graph_seq_ops);
6127 if (!ret) {
6128 struct seq_file *m = file->private_data;
6129 m->private = fgd;
6130 } else {
6131 /* Failed */
6132 free_ftrace_hash(new_hash);
6133 new_hash = NULL;
6134 }
6135 } else
6136 file->private_data = fgd;
6137
6138out:
6139 if (ret < 0 && file->f_mode & FMODE_WRITE)
6140 trace_parser_put(&fgd->parser);
6141
6142 fgd->new_hash = new_hash;
6143
6144 /*
6145 * All uses of fgd->hash must be taken with the graph_lock
6146 * held. The graph_lock is going to be released, so force
6147 * fgd->hash to be reinitialized when it is taken again.
6148 */
6149 fgd->hash = NULL;
6150
6151 return ret;
6152}
6153
6154static int
6155ftrace_graph_open(struct inode *inode, struct file *file)
6156{
6157 struct ftrace_graph_data *fgd;
6158 int ret;
6159
6160 if (unlikely(ftrace_disabled))
6161 return -ENODEV;
6162
6163 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6164 if (fgd == NULL)
6165 return -ENOMEM;
6166
6167 mutex_lock(&graph_lock);
6168
6169 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6170 lockdep_is_held(&graph_lock));
6171 fgd->type = GRAPH_FILTER_FUNCTION;
6172 fgd->seq_ops = &ftrace_graph_seq_ops;
6173
6174 ret = __ftrace_graph_open(inode, file, fgd);
6175 if (ret < 0)
6176 kfree(fgd);
6177
6178 mutex_unlock(&graph_lock);
6179 return ret;
6180}
6181
6182static int
6183ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6184{
6185 struct ftrace_graph_data *fgd;
6186 int ret;
6187
6188 if (unlikely(ftrace_disabled))
6189 return -ENODEV;
6190
6191 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6192 if (fgd == NULL)
6193 return -ENOMEM;
6194
6195 mutex_lock(&graph_lock);
6196
6197 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6198 lockdep_is_held(&graph_lock));
6199 fgd->type = GRAPH_FILTER_NOTRACE;
6200 fgd->seq_ops = &ftrace_graph_seq_ops;
6201
6202 ret = __ftrace_graph_open(inode, file, fgd);
6203 if (ret < 0)
6204 kfree(fgd);
6205
6206 mutex_unlock(&graph_lock);
6207 return ret;
6208}
6209
6210static int
6211ftrace_graph_release(struct inode *inode, struct file *file)
6212{
6213 struct ftrace_graph_data *fgd;
6214 struct ftrace_hash *old_hash, *new_hash;
6215 struct trace_parser *parser;
6216 int ret = 0;
6217
6218 if (file->f_mode & FMODE_READ) {
6219 struct seq_file *m = file->private_data;
6220
6221 fgd = m->private;
6222 seq_release(inode, file);
6223 } else {
6224 fgd = file->private_data;
6225 }
6226
6227
6228 if (file->f_mode & FMODE_WRITE) {
6229
6230 parser = &fgd->parser;
6231
6232 if (trace_parser_loaded((parser))) {
6233 ret = ftrace_graph_set_hash(fgd->new_hash,
6234 parser->buffer);
6235 }
6236
6237 trace_parser_put(parser);
6238
6239 new_hash = __ftrace_hash_move(fgd->new_hash);
6240 if (!new_hash) {
6241 ret = -ENOMEM;
6242 goto out;
6243 }
6244
6245 mutex_lock(&graph_lock);
6246
6247 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6248 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6249 lockdep_is_held(&graph_lock));
6250 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6251 } else {
6252 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6253 lockdep_is_held(&graph_lock));
6254 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6255 }
6256
6257 mutex_unlock(&graph_lock);
6258
6259 /*
6260 * We need to do a hard force of sched synchronization.
6261 * This is because we use preempt_disable() to do RCU, but
6262 * the function tracers can be called where RCU is not watching
6263 * (like before user_exit()). We can not rely on the RCU
6264 * infrastructure to do the synchronization, thus we must do it
6265 * ourselves.
6266 */
6267 if (old_hash != EMPTY_HASH)
6268 synchronize_rcu_tasks_rude();
6269
6270 free_ftrace_hash(old_hash);
6271 }
6272
6273 out:
6274 free_ftrace_hash(fgd->new_hash);
6275 kfree(fgd);
6276
6277 return ret;
6278}
6279
6280static int
6281ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6282{
6283 struct ftrace_glob func_g;
6284 struct dyn_ftrace *rec;
6285 struct ftrace_page *pg;
6286 struct ftrace_func_entry *entry;
6287 int fail = 1;
6288 int not;
6289
6290 /* decode regex */
6291 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6292 &func_g.search, ¬);
6293
6294 func_g.len = strlen(func_g.search);
6295
6296 mutex_lock(&ftrace_lock);
6297
6298 if (unlikely(ftrace_disabled)) {
6299 mutex_unlock(&ftrace_lock);
6300 return -ENODEV;
6301 }
6302
6303 do_for_each_ftrace_rec(pg, rec) {
6304
6305 if (rec->flags & FTRACE_FL_DISABLED)
6306 continue;
6307
6308 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6309 entry = ftrace_lookup_ip(hash, rec->ip);
6310
6311 if (!not) {
6312 fail = 0;
6313
6314 if (entry)
6315 continue;
6316 if (add_hash_entry(hash, rec->ip) == NULL)
6317 goto out;
6318 } else {
6319 if (entry) {
6320 free_hash_entry(hash, entry);
6321 fail = 0;
6322 }
6323 }
6324 }
6325 } while_for_each_ftrace_rec();
6326out:
6327 mutex_unlock(&ftrace_lock);
6328
6329 if (fail)
6330 return -EINVAL;
6331
6332 return 0;
6333}
6334
6335static ssize_t
6336ftrace_graph_write(struct file *file, const char __user *ubuf,
6337 size_t cnt, loff_t *ppos)
6338{
6339 ssize_t read, ret = 0;
6340 struct ftrace_graph_data *fgd = file->private_data;
6341 struct trace_parser *parser;
6342
6343 if (!cnt)
6344 return 0;
6345
6346 /* Read mode uses seq functions */
6347 if (file->f_mode & FMODE_READ) {
6348 struct seq_file *m = file->private_data;
6349 fgd = m->private;
6350 }
6351
6352 parser = &fgd->parser;
6353
6354 read = trace_get_user(parser, ubuf, cnt, ppos);
6355
6356 if (read >= 0 && trace_parser_loaded(parser) &&
6357 !trace_parser_cont(parser)) {
6358
6359 ret = ftrace_graph_set_hash(fgd->new_hash,
6360 parser->buffer);
6361 trace_parser_clear(parser);
6362 }
6363
6364 if (!ret)
6365 ret = read;
6366
6367 return ret;
6368}
6369
6370static const struct file_operations ftrace_graph_fops = {
6371 .open = ftrace_graph_open,
6372 .read = seq_read,
6373 .write = ftrace_graph_write,
6374 .llseek = tracing_lseek,
6375 .release = ftrace_graph_release,
6376};
6377
6378static const struct file_operations ftrace_graph_notrace_fops = {
6379 .open = ftrace_graph_notrace_open,
6380 .read = seq_read,
6381 .write = ftrace_graph_write,
6382 .llseek = tracing_lseek,
6383 .release = ftrace_graph_release,
6384};
6385#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6386
6387void ftrace_create_filter_files(struct ftrace_ops *ops,
6388 struct dentry *parent)
6389{
6390
6391 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6392 ops, &ftrace_filter_fops);
6393
6394 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6395 ops, &ftrace_notrace_fops);
6396}
6397
6398/*
6399 * The name "destroy_filter_files" is really a misnomer. Although
6400 * in the future, it may actually delete the files, but this is
6401 * really intended to make sure the ops passed in are disabled
6402 * and that when this function returns, the caller is free to
6403 * free the ops.
6404 *
6405 * The "destroy" name is only to match the "create" name that this
6406 * should be paired with.
6407 */
6408void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6409{
6410 mutex_lock(&ftrace_lock);
6411 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6412 ftrace_shutdown(ops, 0);
6413 ops->flags |= FTRACE_OPS_FL_DELETED;
6414 ftrace_free_filter(ops);
6415 mutex_unlock(&ftrace_lock);
6416}
6417
6418static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6419{
6420
6421 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6422 d_tracer, NULL, &ftrace_avail_fops);
6423
6424 trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6425 d_tracer, NULL, &ftrace_avail_addrs_fops);
6426
6427 trace_create_file("enabled_functions", TRACE_MODE_READ,
6428 d_tracer, NULL, &ftrace_enabled_fops);
6429
6430 trace_create_file("touched_functions", TRACE_MODE_READ,
6431 d_tracer, NULL, &ftrace_touched_fops);
6432
6433 ftrace_create_filter_files(&global_ops, d_tracer);
6434
6435#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6436 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6437 NULL,
6438 &ftrace_graph_fops);
6439 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6440 NULL,
6441 &ftrace_graph_notrace_fops);
6442#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6443
6444 return 0;
6445}
6446
6447static int ftrace_cmp_ips(const void *a, const void *b)
6448{
6449 const unsigned long *ipa = a;
6450 const unsigned long *ipb = b;
6451
6452 if (*ipa > *ipb)
6453 return 1;
6454 if (*ipa < *ipb)
6455 return -1;
6456 return 0;
6457}
6458
6459#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6460static void test_is_sorted(unsigned long *start, unsigned long count)
6461{
6462 int i;
6463
6464 for (i = 1; i < count; i++) {
6465 if (WARN(start[i - 1] > start[i],
6466 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6467 (void *)start[i - 1], start[i - 1],
6468 (void *)start[i], start[i]))
6469 break;
6470 }
6471 if (i == count)
6472 pr_info("ftrace section at %px sorted properly\n", start);
6473}
6474#else
6475static void test_is_sorted(unsigned long *start, unsigned long count)
6476{
6477}
6478#endif
6479
6480static int ftrace_process_locs(struct module *mod,
6481 unsigned long *start,
6482 unsigned long *end)
6483{
6484 struct ftrace_page *pg_unuse = NULL;
6485 struct ftrace_page *start_pg;
6486 struct ftrace_page *pg;
6487 struct dyn_ftrace *rec;
6488 unsigned long skipped = 0;
6489 unsigned long count;
6490 unsigned long *p;
6491 unsigned long addr;
6492 unsigned long flags = 0; /* Shut up gcc */
6493 int ret = -ENOMEM;
6494
6495 count = end - start;
6496
6497 if (!count)
6498 return 0;
6499
6500 /*
6501 * Sorting mcount in vmlinux at build time depend on
6502 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6503 * modules can not be sorted at build time.
6504 */
6505 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6506 sort(start, count, sizeof(*start),
6507 ftrace_cmp_ips, NULL);
6508 } else {
6509 test_is_sorted(start, count);
6510 }
6511
6512 start_pg = ftrace_allocate_pages(count);
6513 if (!start_pg)
6514 return -ENOMEM;
6515
6516 mutex_lock(&ftrace_lock);
6517
6518 /*
6519 * Core and each module needs their own pages, as
6520 * modules will free them when they are removed.
6521 * Force a new page to be allocated for modules.
6522 */
6523 if (!mod) {
6524 WARN_ON(ftrace_pages || ftrace_pages_start);
6525 /* First initialization */
6526 ftrace_pages = ftrace_pages_start = start_pg;
6527 } else {
6528 if (!ftrace_pages)
6529 goto out;
6530
6531 if (WARN_ON(ftrace_pages->next)) {
6532 /* Hmm, we have free pages? */
6533 while (ftrace_pages->next)
6534 ftrace_pages = ftrace_pages->next;
6535 }
6536
6537 ftrace_pages->next = start_pg;
6538 }
6539
6540 p = start;
6541 pg = start_pg;
6542 while (p < end) {
6543 unsigned long end_offset;
6544 addr = ftrace_call_adjust(*p++);
6545 /*
6546 * Some architecture linkers will pad between
6547 * the different mcount_loc sections of different
6548 * object files to satisfy alignments.
6549 * Skip any NULL pointers.
6550 */
6551 if (!addr) {
6552 skipped++;
6553 continue;
6554 }
6555
6556 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6557 if (end_offset > PAGE_SIZE << pg->order) {
6558 /* We should have allocated enough */
6559 if (WARN_ON(!pg->next))
6560 break;
6561 pg = pg->next;
6562 }
6563
6564 rec = &pg->records[pg->index++];
6565 rec->ip = addr;
6566 }
6567
6568 if (pg->next) {
6569 pg_unuse = pg->next;
6570 pg->next = NULL;
6571 }
6572
6573 /* Assign the last page to ftrace_pages */
6574 ftrace_pages = pg;
6575
6576 /*
6577 * We only need to disable interrupts on start up
6578 * because we are modifying code that an interrupt
6579 * may execute, and the modification is not atomic.
6580 * But for modules, nothing runs the code we modify
6581 * until we are finished with it, and there's no
6582 * reason to cause large interrupt latencies while we do it.
6583 */
6584 if (!mod)
6585 local_irq_save(flags);
6586 ftrace_update_code(mod, start_pg);
6587 if (!mod)
6588 local_irq_restore(flags);
6589 ret = 0;
6590 out:
6591 mutex_unlock(&ftrace_lock);
6592
6593 /* We should have used all pages unless we skipped some */
6594 if (pg_unuse) {
6595 WARN_ON(!skipped);
6596 ftrace_free_pages(pg_unuse);
6597 }
6598 return ret;
6599}
6600
6601struct ftrace_mod_func {
6602 struct list_head list;
6603 char *name;
6604 unsigned long ip;
6605 unsigned int size;
6606};
6607
6608struct ftrace_mod_map {
6609 struct rcu_head rcu;
6610 struct list_head list;
6611 struct module *mod;
6612 unsigned long start_addr;
6613 unsigned long end_addr;
6614 struct list_head funcs;
6615 unsigned int num_funcs;
6616};
6617
6618static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6619 unsigned long *value, char *type,
6620 char *name, char *module_name,
6621 int *exported)
6622{
6623 struct ftrace_ops *op;
6624
6625 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6626 if (!op->trampoline || symnum--)
6627 continue;
6628 *value = op->trampoline;
6629 *type = 't';
6630 strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6631 strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6632 *exported = 0;
6633 return 0;
6634 }
6635
6636 return -ERANGE;
6637}
6638
6639#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6640/*
6641 * Check if the current ops references the given ip.
6642 *
6643 * If the ops traces all functions, then it was already accounted for.
6644 * If the ops does not trace the current record function, skip it.
6645 * If the ops ignores the function via notrace filter, skip it.
6646 */
6647static bool
6648ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6649{
6650 /* If ops isn't enabled, ignore it */
6651 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6652 return false;
6653
6654 /* If ops traces all then it includes this function */
6655 if (ops_traces_mod(ops))
6656 return true;
6657
6658 /* The function must be in the filter */
6659 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6660 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6661 return false;
6662
6663 /* If in notrace hash, we ignore it too */
6664 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6665 return false;
6666
6667 return true;
6668}
6669#endif
6670
6671#ifdef CONFIG_MODULES
6672
6673#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6674
6675static LIST_HEAD(ftrace_mod_maps);
6676
6677static int referenced_filters(struct dyn_ftrace *rec)
6678{
6679 struct ftrace_ops *ops;
6680 int cnt = 0;
6681
6682 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6683 if (ops_references_ip(ops, rec->ip)) {
6684 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6685 continue;
6686 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6687 continue;
6688 cnt++;
6689 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6690 rec->flags |= FTRACE_FL_REGS;
6691 if (cnt == 1 && ops->trampoline)
6692 rec->flags |= FTRACE_FL_TRAMP;
6693 else
6694 rec->flags &= ~FTRACE_FL_TRAMP;
6695 }
6696 }
6697
6698 return cnt;
6699}
6700
6701static void
6702clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6703{
6704 struct ftrace_func_entry *entry;
6705 struct dyn_ftrace *rec;
6706 int i;
6707
6708 if (ftrace_hash_empty(hash))
6709 return;
6710
6711 for (i = 0; i < pg->index; i++) {
6712 rec = &pg->records[i];
6713 entry = __ftrace_lookup_ip(hash, rec->ip);
6714 /*
6715 * Do not allow this rec to match again.
6716 * Yeah, it may waste some memory, but will be removed
6717 * if/when the hash is modified again.
6718 */
6719 if (entry)
6720 entry->ip = 0;
6721 }
6722}
6723
6724/* Clear any records from hashes */
6725static void clear_mod_from_hashes(struct ftrace_page *pg)
6726{
6727 struct trace_array *tr;
6728
6729 mutex_lock(&trace_types_lock);
6730 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6731 if (!tr->ops || !tr->ops->func_hash)
6732 continue;
6733 mutex_lock(&tr->ops->func_hash->regex_lock);
6734 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6735 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6736 mutex_unlock(&tr->ops->func_hash->regex_lock);
6737 }
6738 mutex_unlock(&trace_types_lock);
6739}
6740
6741static void ftrace_free_mod_map(struct rcu_head *rcu)
6742{
6743 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6744 struct ftrace_mod_func *mod_func;
6745 struct ftrace_mod_func *n;
6746
6747 /* All the contents of mod_map are now not visible to readers */
6748 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6749 kfree(mod_func->name);
6750 list_del(&mod_func->list);
6751 kfree(mod_func);
6752 }
6753
6754 kfree(mod_map);
6755}
6756
6757void ftrace_release_mod(struct module *mod)
6758{
6759 struct ftrace_mod_map *mod_map;
6760 struct ftrace_mod_map *n;
6761 struct dyn_ftrace *rec;
6762 struct ftrace_page **last_pg;
6763 struct ftrace_page *tmp_page = NULL;
6764 struct ftrace_page *pg;
6765
6766 mutex_lock(&ftrace_lock);
6767
6768 if (ftrace_disabled)
6769 goto out_unlock;
6770
6771 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6772 if (mod_map->mod == mod) {
6773 list_del_rcu(&mod_map->list);
6774 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6775 break;
6776 }
6777 }
6778
6779 /*
6780 * Each module has its own ftrace_pages, remove
6781 * them from the list.
6782 */
6783 last_pg = &ftrace_pages_start;
6784 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6785 rec = &pg->records[0];
6786 if (within_module(rec->ip, mod)) {
6787 /*
6788 * As core pages are first, the first
6789 * page should never be a module page.
6790 */
6791 if (WARN_ON(pg == ftrace_pages_start))
6792 goto out_unlock;
6793
6794 /* Check if we are deleting the last page */
6795 if (pg == ftrace_pages)
6796 ftrace_pages = next_to_ftrace_page(last_pg);
6797
6798 ftrace_update_tot_cnt -= pg->index;
6799 *last_pg = pg->next;
6800
6801 pg->next = tmp_page;
6802 tmp_page = pg;
6803 } else
6804 last_pg = &pg->next;
6805 }
6806 out_unlock:
6807 mutex_unlock(&ftrace_lock);
6808
6809 for (pg = tmp_page; pg; pg = tmp_page) {
6810
6811 /* Needs to be called outside of ftrace_lock */
6812 clear_mod_from_hashes(pg);
6813
6814 if (pg->records) {
6815 free_pages((unsigned long)pg->records, pg->order);
6816 ftrace_number_of_pages -= 1 << pg->order;
6817 }
6818 tmp_page = pg->next;
6819 kfree(pg);
6820 ftrace_number_of_groups--;
6821 }
6822}
6823
6824void ftrace_module_enable(struct module *mod)
6825{
6826 struct dyn_ftrace *rec;
6827 struct ftrace_page *pg;
6828
6829 mutex_lock(&ftrace_lock);
6830
6831 if (ftrace_disabled)
6832 goto out_unlock;
6833
6834 /*
6835 * If the tracing is enabled, go ahead and enable the record.
6836 *
6837 * The reason not to enable the record immediately is the
6838 * inherent check of ftrace_make_nop/ftrace_make_call for
6839 * correct previous instructions. Making first the NOP
6840 * conversion puts the module to the correct state, thus
6841 * passing the ftrace_make_call check.
6842 *
6843 * We also delay this to after the module code already set the
6844 * text to read-only, as we now need to set it back to read-write
6845 * so that we can modify the text.
6846 */
6847 if (ftrace_start_up)
6848 ftrace_arch_code_modify_prepare();
6849
6850 do_for_each_ftrace_rec(pg, rec) {
6851 int cnt;
6852 /*
6853 * do_for_each_ftrace_rec() is a double loop.
6854 * module text shares the pg. If a record is
6855 * not part of this module, then skip this pg,
6856 * which the "break" will do.
6857 */
6858 if (!within_module(rec->ip, mod))
6859 break;
6860
6861 /* Weak functions should still be ignored */
6862 if (!test_for_valid_rec(rec)) {
6863 /* Clear all other flags. Should not be enabled anyway */
6864 rec->flags = FTRACE_FL_DISABLED;
6865 continue;
6866 }
6867
6868 cnt = 0;
6869
6870 /*
6871 * When adding a module, we need to check if tracers are
6872 * currently enabled and if they are, and can trace this record,
6873 * we need to enable the module functions as well as update the
6874 * reference counts for those function records.
6875 */
6876 if (ftrace_start_up)
6877 cnt += referenced_filters(rec);
6878
6879 rec->flags &= ~FTRACE_FL_DISABLED;
6880 rec->flags += cnt;
6881
6882 if (ftrace_start_up && cnt) {
6883 int failed = __ftrace_replace_code(rec, 1);
6884 if (failed) {
6885 ftrace_bug(failed, rec);
6886 goto out_loop;
6887 }
6888 }
6889
6890 } while_for_each_ftrace_rec();
6891
6892 out_loop:
6893 if (ftrace_start_up)
6894 ftrace_arch_code_modify_post_process();
6895
6896 out_unlock:
6897 mutex_unlock(&ftrace_lock);
6898
6899 process_cached_mods(mod->name);
6900}
6901
6902void ftrace_module_init(struct module *mod)
6903{
6904 int ret;
6905
6906 if (ftrace_disabled || !mod->num_ftrace_callsites)
6907 return;
6908
6909 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6910 mod->ftrace_callsites + mod->num_ftrace_callsites);
6911 if (ret)
6912 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6913 mod->name);
6914}
6915
6916static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6917 struct dyn_ftrace *rec)
6918{
6919 struct ftrace_mod_func *mod_func;
6920 unsigned long symsize;
6921 unsigned long offset;
6922 char str[KSYM_SYMBOL_LEN];
6923 char *modname;
6924 const char *ret;
6925
6926 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6927 if (!ret)
6928 return;
6929
6930 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6931 if (!mod_func)
6932 return;
6933
6934 mod_func->name = kstrdup(str, GFP_KERNEL);
6935 if (!mod_func->name) {
6936 kfree(mod_func);
6937 return;
6938 }
6939
6940 mod_func->ip = rec->ip - offset;
6941 mod_func->size = symsize;
6942
6943 mod_map->num_funcs++;
6944
6945 list_add_rcu(&mod_func->list, &mod_map->funcs);
6946}
6947
6948static struct ftrace_mod_map *
6949allocate_ftrace_mod_map(struct module *mod,
6950 unsigned long start, unsigned long end)
6951{
6952 struct ftrace_mod_map *mod_map;
6953
6954 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6955 if (!mod_map)
6956 return NULL;
6957
6958 mod_map->mod = mod;
6959 mod_map->start_addr = start;
6960 mod_map->end_addr = end;
6961 mod_map->num_funcs = 0;
6962
6963 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6964
6965 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6966
6967 return mod_map;
6968}
6969
6970static const char *
6971ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6972 unsigned long addr, unsigned long *size,
6973 unsigned long *off, char *sym)
6974{
6975 struct ftrace_mod_func *found_func = NULL;
6976 struct ftrace_mod_func *mod_func;
6977
6978 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6979 if (addr >= mod_func->ip &&
6980 addr < mod_func->ip + mod_func->size) {
6981 found_func = mod_func;
6982 break;
6983 }
6984 }
6985
6986 if (found_func) {
6987 if (size)
6988 *size = found_func->size;
6989 if (off)
6990 *off = addr - found_func->ip;
6991 if (sym)
6992 strscpy(sym, found_func->name, KSYM_NAME_LEN);
6993
6994 return found_func->name;
6995 }
6996
6997 return NULL;
6998}
6999
7000const char *
7001ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7002 unsigned long *off, char **modname, char *sym)
7003{
7004 struct ftrace_mod_map *mod_map;
7005 const char *ret = NULL;
7006
7007 /* mod_map is freed via call_rcu() */
7008 preempt_disable();
7009 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7010 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7011 if (ret) {
7012 if (modname)
7013 *modname = mod_map->mod->name;
7014 break;
7015 }
7016 }
7017 preempt_enable();
7018
7019 return ret;
7020}
7021
7022int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7023 char *type, char *name,
7024 char *module_name, int *exported)
7025{
7026 struct ftrace_mod_map *mod_map;
7027 struct ftrace_mod_func *mod_func;
7028 int ret;
7029
7030 preempt_disable();
7031 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7032
7033 if (symnum >= mod_map->num_funcs) {
7034 symnum -= mod_map->num_funcs;
7035 continue;
7036 }
7037
7038 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7039 if (symnum > 1) {
7040 symnum--;
7041 continue;
7042 }
7043
7044 *value = mod_func->ip;
7045 *type = 'T';
7046 strscpy(name, mod_func->name, KSYM_NAME_LEN);
7047 strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7048 *exported = 1;
7049 preempt_enable();
7050 return 0;
7051 }
7052 WARN_ON(1);
7053 break;
7054 }
7055 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7056 module_name, exported);
7057 preempt_enable();
7058 return ret;
7059}
7060
7061#else
7062static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7063 struct dyn_ftrace *rec) { }
7064static inline struct ftrace_mod_map *
7065allocate_ftrace_mod_map(struct module *mod,
7066 unsigned long start, unsigned long end)
7067{
7068 return NULL;
7069}
7070int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7071 char *type, char *name, char *module_name,
7072 int *exported)
7073{
7074 int ret;
7075
7076 preempt_disable();
7077 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7078 module_name, exported);
7079 preempt_enable();
7080 return ret;
7081}
7082#endif /* CONFIG_MODULES */
7083
7084struct ftrace_init_func {
7085 struct list_head list;
7086 unsigned long ip;
7087};
7088
7089/* Clear any init ips from hashes */
7090static void
7091clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7092{
7093 struct ftrace_func_entry *entry;
7094
7095 entry = ftrace_lookup_ip(hash, func->ip);
7096 /*
7097 * Do not allow this rec to match again.
7098 * Yeah, it may waste some memory, but will be removed
7099 * if/when the hash is modified again.
7100 */
7101 if (entry)
7102 entry->ip = 0;
7103}
7104
7105static void
7106clear_func_from_hashes(struct ftrace_init_func *func)
7107{
7108 struct trace_array *tr;
7109
7110 mutex_lock(&trace_types_lock);
7111 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7112 if (!tr->ops || !tr->ops->func_hash)
7113 continue;
7114 mutex_lock(&tr->ops->func_hash->regex_lock);
7115 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7116 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7117 mutex_unlock(&tr->ops->func_hash->regex_lock);
7118 }
7119 mutex_unlock(&trace_types_lock);
7120}
7121
7122static void add_to_clear_hash_list(struct list_head *clear_list,
7123 struct dyn_ftrace *rec)
7124{
7125 struct ftrace_init_func *func;
7126
7127 func = kmalloc(sizeof(*func), GFP_KERNEL);
7128 if (!func) {
7129 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7130 return;
7131 }
7132
7133 func->ip = rec->ip;
7134 list_add(&func->list, clear_list);
7135}
7136
7137void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7138{
7139 unsigned long start = (unsigned long)(start_ptr);
7140 unsigned long end = (unsigned long)(end_ptr);
7141 struct ftrace_page **last_pg = &ftrace_pages_start;
7142 struct ftrace_page *pg;
7143 struct dyn_ftrace *rec;
7144 struct dyn_ftrace key;
7145 struct ftrace_mod_map *mod_map = NULL;
7146 struct ftrace_init_func *func, *func_next;
7147 LIST_HEAD(clear_hash);
7148
7149 key.ip = start;
7150 key.flags = end; /* overload flags, as it is unsigned long */
7151
7152 mutex_lock(&ftrace_lock);
7153
7154 /*
7155 * If we are freeing module init memory, then check if
7156 * any tracer is active. If so, we need to save a mapping of
7157 * the module functions being freed with the address.
7158 */
7159 if (mod && ftrace_ops_list != &ftrace_list_end)
7160 mod_map = allocate_ftrace_mod_map(mod, start, end);
7161
7162 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7163 if (end < pg->records[0].ip ||
7164 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7165 continue;
7166 again:
7167 rec = bsearch(&key, pg->records, pg->index,
7168 sizeof(struct dyn_ftrace),
7169 ftrace_cmp_recs);
7170 if (!rec)
7171 continue;
7172
7173 /* rec will be cleared from hashes after ftrace_lock unlock */
7174 add_to_clear_hash_list(&clear_hash, rec);
7175
7176 if (mod_map)
7177 save_ftrace_mod_rec(mod_map, rec);
7178
7179 pg->index--;
7180 ftrace_update_tot_cnt--;
7181 if (!pg->index) {
7182 *last_pg = pg->next;
7183 if (pg->records) {
7184 free_pages((unsigned long)pg->records, pg->order);
7185 ftrace_number_of_pages -= 1 << pg->order;
7186 }
7187 ftrace_number_of_groups--;
7188 kfree(pg);
7189 pg = container_of(last_pg, struct ftrace_page, next);
7190 if (!(*last_pg))
7191 ftrace_pages = pg;
7192 continue;
7193 }
7194 memmove(rec, rec + 1,
7195 (pg->index - (rec - pg->records)) * sizeof(*rec));
7196 /* More than one function may be in this block */
7197 goto again;
7198 }
7199 mutex_unlock(&ftrace_lock);
7200
7201 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7202 clear_func_from_hashes(func);
7203 kfree(func);
7204 }
7205}
7206
7207void __init ftrace_free_init_mem(void)
7208{
7209 void *start = (void *)(&__init_begin);
7210 void *end = (void *)(&__init_end);
7211
7212 ftrace_boot_snapshot();
7213
7214 ftrace_free_mem(NULL, start, end);
7215}
7216
7217int __init __weak ftrace_dyn_arch_init(void)
7218{
7219 return 0;
7220}
7221
7222void __init ftrace_init(void)
7223{
7224 extern unsigned long __start_mcount_loc[];
7225 extern unsigned long __stop_mcount_loc[];
7226 unsigned long count, flags;
7227 int ret;
7228
7229 local_irq_save(flags);
7230 ret = ftrace_dyn_arch_init();
7231 local_irq_restore(flags);
7232 if (ret)
7233 goto failed;
7234
7235 count = __stop_mcount_loc - __start_mcount_loc;
7236 if (!count) {
7237 pr_info("ftrace: No functions to be traced?\n");
7238 goto failed;
7239 }
7240
7241 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7242 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7243
7244 ret = ftrace_process_locs(NULL,
7245 __start_mcount_loc,
7246 __stop_mcount_loc);
7247 if (ret) {
7248 pr_warn("ftrace: failed to allocate entries for functions\n");
7249 goto failed;
7250 }
7251
7252 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7253 ftrace_number_of_pages, ftrace_number_of_groups);
7254
7255 last_ftrace_enabled = ftrace_enabled = 1;
7256
7257 set_ftrace_early_filters();
7258
7259 return;
7260 failed:
7261 ftrace_disabled = 1;
7262}
7263
7264/* Do nothing if arch does not support this */
7265void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7266{
7267}
7268
7269static void ftrace_update_trampoline(struct ftrace_ops *ops)
7270{
7271 unsigned long trampoline = ops->trampoline;
7272
7273 arch_ftrace_update_trampoline(ops);
7274 if (ops->trampoline && ops->trampoline != trampoline &&
7275 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7276 /* Add to kallsyms before the perf events */
7277 ftrace_add_trampoline_to_kallsyms(ops);
7278 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7279 ops->trampoline, ops->trampoline_size, false,
7280 FTRACE_TRAMPOLINE_SYM);
7281 /*
7282 * Record the perf text poke event after the ksymbol register
7283 * event.
7284 */
7285 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7286 (void *)ops->trampoline,
7287 ops->trampoline_size);
7288 }
7289}
7290
7291void ftrace_init_trace_array(struct trace_array *tr)
7292{
7293 INIT_LIST_HEAD(&tr->func_probes);
7294 INIT_LIST_HEAD(&tr->mod_trace);
7295 INIT_LIST_HEAD(&tr->mod_notrace);
7296}
7297#else
7298
7299struct ftrace_ops global_ops = {
7300 .func = ftrace_stub,
7301 .flags = FTRACE_OPS_FL_INITIALIZED |
7302 FTRACE_OPS_FL_PID,
7303};
7304
7305static int __init ftrace_nodyn_init(void)
7306{
7307 ftrace_enabled = 1;
7308 return 0;
7309}
7310core_initcall(ftrace_nodyn_init);
7311
7312static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7313static inline void ftrace_startup_all(int command) { }
7314
7315static void ftrace_update_trampoline(struct ftrace_ops *ops)
7316{
7317}
7318
7319#endif /* CONFIG_DYNAMIC_FTRACE */
7320
7321__init void ftrace_init_global_array_ops(struct trace_array *tr)
7322{
7323 tr->ops = &global_ops;
7324 tr->ops->private = tr;
7325 ftrace_init_trace_array(tr);
7326}
7327
7328void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7329{
7330 /* If we filter on pids, update to use the pid function */
7331 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7332 if (WARN_ON(tr->ops->func != ftrace_stub))
7333 printk("ftrace ops had %pS for function\n",
7334 tr->ops->func);
7335 }
7336 tr->ops->func = func;
7337 tr->ops->private = tr;
7338}
7339
7340void ftrace_reset_array_ops(struct trace_array *tr)
7341{
7342 tr->ops->func = ftrace_stub;
7343}
7344
7345static nokprobe_inline void
7346__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7347 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7348{
7349 struct pt_regs *regs = ftrace_get_regs(fregs);
7350 struct ftrace_ops *op;
7351 int bit;
7352
7353 /*
7354 * The ftrace_test_and_set_recursion() will disable preemption,
7355 * which is required since some of the ops may be dynamically
7356 * allocated, they must be freed after a synchronize_rcu().
7357 */
7358 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7359 if (bit < 0)
7360 return;
7361
7362 do_for_each_ftrace_op(op, ftrace_ops_list) {
7363 /* Stub functions don't need to be called nor tested */
7364 if (op->flags & FTRACE_OPS_FL_STUB)
7365 continue;
7366 /*
7367 * Check the following for each ops before calling their func:
7368 * if RCU flag is set, then rcu_is_watching() must be true
7369 * Otherwise test if the ip matches the ops filter
7370 *
7371 * If any of the above fails then the op->func() is not executed.
7372 */
7373 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7374 ftrace_ops_test(op, ip, regs)) {
7375 if (FTRACE_WARN_ON(!op->func)) {
7376 pr_warn("op=%p %pS\n", op, op);
7377 goto out;
7378 }
7379 op->func(ip, parent_ip, op, fregs);
7380 }
7381 } while_for_each_ftrace_op(op);
7382out:
7383 trace_clear_recursion(bit);
7384}
7385
7386/*
7387 * Some archs only support passing ip and parent_ip. Even though
7388 * the list function ignores the op parameter, we do not want any
7389 * C side effects, where a function is called without the caller
7390 * sending a third parameter.
7391 * Archs are to support both the regs and ftrace_ops at the same time.
7392 * If they support ftrace_ops, it is assumed they support regs.
7393 * If call backs want to use regs, they must either check for regs
7394 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7395 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7396 * An architecture can pass partial regs with ftrace_ops and still
7397 * set the ARCH_SUPPORTS_FTRACE_OPS.
7398 *
7399 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7400 * arch_ftrace_ops_list_func.
7401 */
7402#if ARCH_SUPPORTS_FTRACE_OPS
7403void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7404 struct ftrace_ops *op, struct ftrace_regs *fregs)
7405{
7406 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7407}
7408#else
7409void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7410{
7411 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7412}
7413#endif
7414NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7415
7416/*
7417 * If there's only one function registered but it does not support
7418 * recursion, needs RCU protection, then this function will be called
7419 * by the mcount trampoline.
7420 */
7421static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7422 struct ftrace_ops *op, struct ftrace_regs *fregs)
7423{
7424 int bit;
7425
7426 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7427 if (bit < 0)
7428 return;
7429
7430 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7431 op->func(ip, parent_ip, op, fregs);
7432
7433 trace_clear_recursion(bit);
7434}
7435NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7436
7437/**
7438 * ftrace_ops_get_func - get the function a trampoline should call
7439 * @ops: the ops to get the function for
7440 *
7441 * Normally the mcount trampoline will call the ops->func, but there
7442 * are times that it should not. For example, if the ops does not
7443 * have its own recursion protection, then it should call the
7444 * ftrace_ops_assist_func() instead.
7445 *
7446 * Returns the function that the trampoline should call for @ops.
7447 */
7448ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7449{
7450 /*
7451 * If the function does not handle recursion or needs to be RCU safe,
7452 * then we need to call the assist handler.
7453 */
7454 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7455 FTRACE_OPS_FL_RCU))
7456 return ftrace_ops_assist_func;
7457
7458 return ops->func;
7459}
7460
7461static void
7462ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7463 struct task_struct *prev,
7464 struct task_struct *next,
7465 unsigned int prev_state)
7466{
7467 struct trace_array *tr = data;
7468 struct trace_pid_list *pid_list;
7469 struct trace_pid_list *no_pid_list;
7470
7471 pid_list = rcu_dereference_sched(tr->function_pids);
7472 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7473
7474 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7475 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7476 FTRACE_PID_IGNORE);
7477 else
7478 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7479 next->pid);
7480}
7481
7482static void
7483ftrace_pid_follow_sched_process_fork(void *data,
7484 struct task_struct *self,
7485 struct task_struct *task)
7486{
7487 struct trace_pid_list *pid_list;
7488 struct trace_array *tr = data;
7489
7490 pid_list = rcu_dereference_sched(tr->function_pids);
7491 trace_filter_add_remove_task(pid_list, self, task);
7492
7493 pid_list = rcu_dereference_sched(tr->function_no_pids);
7494 trace_filter_add_remove_task(pid_list, self, task);
7495}
7496
7497static void
7498ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7499{
7500 struct trace_pid_list *pid_list;
7501 struct trace_array *tr = data;
7502
7503 pid_list = rcu_dereference_sched(tr->function_pids);
7504 trace_filter_add_remove_task(pid_list, NULL, task);
7505
7506 pid_list = rcu_dereference_sched(tr->function_no_pids);
7507 trace_filter_add_remove_task(pid_list, NULL, task);
7508}
7509
7510void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7511{
7512 if (enable) {
7513 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7514 tr);
7515 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7516 tr);
7517 } else {
7518 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7519 tr);
7520 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7521 tr);
7522 }
7523}
7524
7525static void clear_ftrace_pids(struct trace_array *tr, int type)
7526{
7527 struct trace_pid_list *pid_list;
7528 struct trace_pid_list *no_pid_list;
7529 int cpu;
7530
7531 pid_list = rcu_dereference_protected(tr->function_pids,
7532 lockdep_is_held(&ftrace_lock));
7533 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7534 lockdep_is_held(&ftrace_lock));
7535
7536 /* Make sure there's something to do */
7537 if (!pid_type_enabled(type, pid_list, no_pid_list))
7538 return;
7539
7540 /* See if the pids still need to be checked after this */
7541 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7542 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7543 for_each_possible_cpu(cpu)
7544 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7545 }
7546
7547 if (type & TRACE_PIDS)
7548 rcu_assign_pointer(tr->function_pids, NULL);
7549
7550 if (type & TRACE_NO_PIDS)
7551 rcu_assign_pointer(tr->function_no_pids, NULL);
7552
7553 /* Wait till all users are no longer using pid filtering */
7554 synchronize_rcu();
7555
7556 if ((type & TRACE_PIDS) && pid_list)
7557 trace_pid_list_free(pid_list);
7558
7559 if ((type & TRACE_NO_PIDS) && no_pid_list)
7560 trace_pid_list_free(no_pid_list);
7561}
7562
7563void ftrace_clear_pids(struct trace_array *tr)
7564{
7565 mutex_lock(&ftrace_lock);
7566
7567 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7568
7569 mutex_unlock(&ftrace_lock);
7570}
7571
7572static void ftrace_pid_reset(struct trace_array *tr, int type)
7573{
7574 mutex_lock(&ftrace_lock);
7575 clear_ftrace_pids(tr, type);
7576
7577 ftrace_update_pid_func();
7578 ftrace_startup_all(0);
7579
7580 mutex_unlock(&ftrace_lock);
7581}
7582
7583/* Greater than any max PID */
7584#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7585
7586static void *fpid_start(struct seq_file *m, loff_t *pos)
7587 __acquires(RCU)
7588{
7589 struct trace_pid_list *pid_list;
7590 struct trace_array *tr = m->private;
7591
7592 mutex_lock(&ftrace_lock);
7593 rcu_read_lock_sched();
7594
7595 pid_list = rcu_dereference_sched(tr->function_pids);
7596
7597 if (!pid_list)
7598 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7599
7600 return trace_pid_start(pid_list, pos);
7601}
7602
7603static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7604{
7605 struct trace_array *tr = m->private;
7606 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7607
7608 if (v == FTRACE_NO_PIDS) {
7609 (*pos)++;
7610 return NULL;
7611 }
7612 return trace_pid_next(pid_list, v, pos);
7613}
7614
7615static void fpid_stop(struct seq_file *m, void *p)
7616 __releases(RCU)
7617{
7618 rcu_read_unlock_sched();
7619 mutex_unlock(&ftrace_lock);
7620}
7621
7622static int fpid_show(struct seq_file *m, void *v)
7623{
7624 if (v == FTRACE_NO_PIDS) {
7625 seq_puts(m, "no pid\n");
7626 return 0;
7627 }
7628
7629 return trace_pid_show(m, v);
7630}
7631
7632static const struct seq_operations ftrace_pid_sops = {
7633 .start = fpid_start,
7634 .next = fpid_next,
7635 .stop = fpid_stop,
7636 .show = fpid_show,
7637};
7638
7639static void *fnpid_start(struct seq_file *m, loff_t *pos)
7640 __acquires(RCU)
7641{
7642 struct trace_pid_list *pid_list;
7643 struct trace_array *tr = m->private;
7644
7645 mutex_lock(&ftrace_lock);
7646 rcu_read_lock_sched();
7647
7648 pid_list = rcu_dereference_sched(tr->function_no_pids);
7649
7650 if (!pid_list)
7651 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7652
7653 return trace_pid_start(pid_list, pos);
7654}
7655
7656static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7657{
7658 struct trace_array *tr = m->private;
7659 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7660
7661 if (v == FTRACE_NO_PIDS) {
7662 (*pos)++;
7663 return NULL;
7664 }
7665 return trace_pid_next(pid_list, v, pos);
7666}
7667
7668static const struct seq_operations ftrace_no_pid_sops = {
7669 .start = fnpid_start,
7670 .next = fnpid_next,
7671 .stop = fpid_stop,
7672 .show = fpid_show,
7673};
7674
7675static int pid_open(struct inode *inode, struct file *file, int type)
7676{
7677 const struct seq_operations *seq_ops;
7678 struct trace_array *tr = inode->i_private;
7679 struct seq_file *m;
7680 int ret = 0;
7681
7682 ret = tracing_check_open_get_tr(tr);
7683 if (ret)
7684 return ret;
7685
7686 if ((file->f_mode & FMODE_WRITE) &&
7687 (file->f_flags & O_TRUNC))
7688 ftrace_pid_reset(tr, type);
7689
7690 switch (type) {
7691 case TRACE_PIDS:
7692 seq_ops = &ftrace_pid_sops;
7693 break;
7694 case TRACE_NO_PIDS:
7695 seq_ops = &ftrace_no_pid_sops;
7696 break;
7697 default:
7698 trace_array_put(tr);
7699 WARN_ON_ONCE(1);
7700 return -EINVAL;
7701 }
7702
7703 ret = seq_open(file, seq_ops);
7704 if (ret < 0) {
7705 trace_array_put(tr);
7706 } else {
7707 m = file->private_data;
7708 /* copy tr over to seq ops */
7709 m->private = tr;
7710 }
7711
7712 return ret;
7713}
7714
7715static int
7716ftrace_pid_open(struct inode *inode, struct file *file)
7717{
7718 return pid_open(inode, file, TRACE_PIDS);
7719}
7720
7721static int
7722ftrace_no_pid_open(struct inode *inode, struct file *file)
7723{
7724 return pid_open(inode, file, TRACE_NO_PIDS);
7725}
7726
7727static void ignore_task_cpu(void *data)
7728{
7729 struct trace_array *tr = data;
7730 struct trace_pid_list *pid_list;
7731 struct trace_pid_list *no_pid_list;
7732
7733 /*
7734 * This function is called by on_each_cpu() while the
7735 * event_mutex is held.
7736 */
7737 pid_list = rcu_dereference_protected(tr->function_pids,
7738 mutex_is_locked(&ftrace_lock));
7739 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7740 mutex_is_locked(&ftrace_lock));
7741
7742 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7743 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7744 FTRACE_PID_IGNORE);
7745 else
7746 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7747 current->pid);
7748}
7749
7750static ssize_t
7751pid_write(struct file *filp, const char __user *ubuf,
7752 size_t cnt, loff_t *ppos, int type)
7753{
7754 struct seq_file *m = filp->private_data;
7755 struct trace_array *tr = m->private;
7756 struct trace_pid_list *filtered_pids;
7757 struct trace_pid_list *other_pids;
7758 struct trace_pid_list *pid_list;
7759 ssize_t ret;
7760
7761 if (!cnt)
7762 return 0;
7763
7764 mutex_lock(&ftrace_lock);
7765
7766 switch (type) {
7767 case TRACE_PIDS:
7768 filtered_pids = rcu_dereference_protected(tr->function_pids,
7769 lockdep_is_held(&ftrace_lock));
7770 other_pids = rcu_dereference_protected(tr->function_no_pids,
7771 lockdep_is_held(&ftrace_lock));
7772 break;
7773 case TRACE_NO_PIDS:
7774 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7775 lockdep_is_held(&ftrace_lock));
7776 other_pids = rcu_dereference_protected(tr->function_pids,
7777 lockdep_is_held(&ftrace_lock));
7778 break;
7779 default:
7780 ret = -EINVAL;
7781 WARN_ON_ONCE(1);
7782 goto out;
7783 }
7784
7785 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7786 if (ret < 0)
7787 goto out;
7788
7789 switch (type) {
7790 case TRACE_PIDS:
7791 rcu_assign_pointer(tr->function_pids, pid_list);
7792 break;
7793 case TRACE_NO_PIDS:
7794 rcu_assign_pointer(tr->function_no_pids, pid_list);
7795 break;
7796 }
7797
7798
7799 if (filtered_pids) {
7800 synchronize_rcu();
7801 trace_pid_list_free(filtered_pids);
7802 } else if (pid_list && !other_pids) {
7803 /* Register a probe to set whether to ignore the tracing of a task */
7804 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7805 }
7806
7807 /*
7808 * Ignoring of pids is done at task switch. But we have to
7809 * check for those tasks that are currently running.
7810 * Always do this in case a pid was appended or removed.
7811 */
7812 on_each_cpu(ignore_task_cpu, tr, 1);
7813
7814 ftrace_update_pid_func();
7815 ftrace_startup_all(0);
7816 out:
7817 mutex_unlock(&ftrace_lock);
7818
7819 if (ret > 0)
7820 *ppos += ret;
7821
7822 return ret;
7823}
7824
7825static ssize_t
7826ftrace_pid_write(struct file *filp, const char __user *ubuf,
7827 size_t cnt, loff_t *ppos)
7828{
7829 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7830}
7831
7832static ssize_t
7833ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7834 size_t cnt, loff_t *ppos)
7835{
7836 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7837}
7838
7839static int
7840ftrace_pid_release(struct inode *inode, struct file *file)
7841{
7842 struct trace_array *tr = inode->i_private;
7843
7844 trace_array_put(tr);
7845
7846 return seq_release(inode, file);
7847}
7848
7849static const struct file_operations ftrace_pid_fops = {
7850 .open = ftrace_pid_open,
7851 .write = ftrace_pid_write,
7852 .read = seq_read,
7853 .llseek = tracing_lseek,
7854 .release = ftrace_pid_release,
7855};
7856
7857static const struct file_operations ftrace_no_pid_fops = {
7858 .open = ftrace_no_pid_open,
7859 .write = ftrace_no_pid_write,
7860 .read = seq_read,
7861 .llseek = tracing_lseek,
7862 .release = ftrace_pid_release,
7863};
7864
7865void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7866{
7867 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7868 tr, &ftrace_pid_fops);
7869 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7870 d_tracer, tr, &ftrace_no_pid_fops);
7871}
7872
7873void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7874 struct dentry *d_tracer)
7875{
7876 /* Only the top level directory has the dyn_tracefs and profile */
7877 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7878
7879 ftrace_init_dyn_tracefs(d_tracer);
7880 ftrace_profile_tracefs(d_tracer);
7881}
7882
7883/**
7884 * ftrace_kill - kill ftrace
7885 *
7886 * This function should be used by panic code. It stops ftrace
7887 * but in a not so nice way. If you need to simply kill ftrace
7888 * from a non-atomic section, use ftrace_kill.
7889 */
7890void ftrace_kill(void)
7891{
7892 ftrace_disabled = 1;
7893 ftrace_enabled = 0;
7894 ftrace_trace_function = ftrace_stub;
7895}
7896
7897/**
7898 * ftrace_is_dead - Test if ftrace is dead or not.
7899 *
7900 * Returns 1 if ftrace is "dead", zero otherwise.
7901 */
7902int ftrace_is_dead(void)
7903{
7904 return ftrace_disabled;
7905}
7906
7907#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7908/*
7909 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7910 * it doesn't conflict with any direct ftrace_ops. If there is existing
7911 * direct ftrace_ops on a kernel function being patched, call
7912 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7913 *
7914 * @ops: ftrace_ops being registered.
7915 *
7916 * Returns:
7917 * 0 on success;
7918 * Negative on failure.
7919 */
7920static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7921{
7922 struct ftrace_func_entry *entry;
7923 struct ftrace_hash *hash;
7924 struct ftrace_ops *op;
7925 int size, i, ret;
7926
7927 lockdep_assert_held_once(&direct_mutex);
7928
7929 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7930 return 0;
7931
7932 hash = ops->func_hash->filter_hash;
7933 size = 1 << hash->size_bits;
7934 for (i = 0; i < size; i++) {
7935 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7936 unsigned long ip = entry->ip;
7937 bool found_op = false;
7938
7939 mutex_lock(&ftrace_lock);
7940 do_for_each_ftrace_op(op, ftrace_ops_list) {
7941 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7942 continue;
7943 if (ops_references_ip(op, ip)) {
7944 found_op = true;
7945 break;
7946 }
7947 } while_for_each_ftrace_op(op);
7948 mutex_unlock(&ftrace_lock);
7949
7950 if (found_op) {
7951 if (!op->ops_func)
7952 return -EBUSY;
7953
7954 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7955 if (ret)
7956 return ret;
7957 }
7958 }
7959 }
7960
7961 return 0;
7962}
7963
7964/*
7965 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7966 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7967 * ops.
7968 */
7969static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7970{
7971 struct ftrace_func_entry *entry;
7972 struct ftrace_hash *hash;
7973 struct ftrace_ops *op;
7974 int size, i;
7975
7976 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7977 return;
7978
7979 mutex_lock(&direct_mutex);
7980
7981 hash = ops->func_hash->filter_hash;
7982 size = 1 << hash->size_bits;
7983 for (i = 0; i < size; i++) {
7984 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7985 unsigned long ip = entry->ip;
7986 bool found_op = false;
7987
7988 mutex_lock(&ftrace_lock);
7989 do_for_each_ftrace_op(op, ftrace_ops_list) {
7990 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7991 continue;
7992 if (ops_references_ip(op, ip)) {
7993 found_op = true;
7994 break;
7995 }
7996 } while_for_each_ftrace_op(op);
7997 mutex_unlock(&ftrace_lock);
7998
7999 /* The cleanup is optional, ignore any errors */
8000 if (found_op && op->ops_func)
8001 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8002 }
8003 }
8004 mutex_unlock(&direct_mutex);
8005}
8006
8007#define lock_direct_mutex() mutex_lock(&direct_mutex)
8008#define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8009
8010#else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8011
8012static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8013{
8014 return 0;
8015}
8016
8017static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8018{
8019}
8020
8021#define lock_direct_mutex() do { } while (0)
8022#define unlock_direct_mutex() do { } while (0)
8023
8024#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8025
8026/*
8027 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8028 */
8029static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8030{
8031 int ret;
8032
8033 ftrace_ops_init(ops);
8034
8035 mutex_lock(&ftrace_lock);
8036
8037 ret = ftrace_startup(ops, 0);
8038
8039 mutex_unlock(&ftrace_lock);
8040
8041 return ret;
8042}
8043
8044/**
8045 * register_ftrace_function - register a function for profiling
8046 * @ops: ops structure that holds the function for profiling.
8047 *
8048 * Register a function to be called by all functions in the
8049 * kernel.
8050 *
8051 * Note: @ops->func and all the functions it calls must be labeled
8052 * with "notrace", otherwise it will go into a
8053 * recursive loop.
8054 */
8055int register_ftrace_function(struct ftrace_ops *ops)
8056{
8057 int ret;
8058
8059 lock_direct_mutex();
8060 ret = prepare_direct_functions_for_ipmodify(ops);
8061 if (ret < 0)
8062 goto out_unlock;
8063
8064 ret = register_ftrace_function_nolock(ops);
8065
8066out_unlock:
8067 unlock_direct_mutex();
8068 return ret;
8069}
8070EXPORT_SYMBOL_GPL(register_ftrace_function);
8071
8072/**
8073 * unregister_ftrace_function - unregister a function for profiling.
8074 * @ops: ops structure that holds the function to unregister
8075 *
8076 * Unregister a function that was added to be called by ftrace profiling.
8077 */
8078int unregister_ftrace_function(struct ftrace_ops *ops)
8079{
8080 int ret;
8081
8082 mutex_lock(&ftrace_lock);
8083 ret = ftrace_shutdown(ops, 0);
8084 mutex_unlock(&ftrace_lock);
8085
8086 cleanup_direct_functions_after_ipmodify(ops);
8087 return ret;
8088}
8089EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8090
8091static int symbols_cmp(const void *a, const void *b)
8092{
8093 const char **str_a = (const char **) a;
8094 const char **str_b = (const char **) b;
8095
8096 return strcmp(*str_a, *str_b);
8097}
8098
8099struct kallsyms_data {
8100 unsigned long *addrs;
8101 const char **syms;
8102 size_t cnt;
8103 size_t found;
8104};
8105
8106/* This function gets called for all kernel and module symbols
8107 * and returns 1 in case we resolved all the requested symbols,
8108 * 0 otherwise.
8109 */
8110static int kallsyms_callback(void *data, const char *name, unsigned long addr)
8111{
8112 struct kallsyms_data *args = data;
8113 const char **sym;
8114 int idx;
8115
8116 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8117 if (!sym)
8118 return 0;
8119
8120 idx = sym - args->syms;
8121 if (args->addrs[idx])
8122 return 0;
8123
8124 if (!ftrace_location(addr))
8125 return 0;
8126
8127 args->addrs[idx] = addr;
8128 args->found++;
8129 return args->found == args->cnt ? 1 : 0;
8130}
8131
8132/**
8133 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8134 *
8135 * @sorted_syms: array of symbols pointers symbols to resolve,
8136 * must be alphabetically sorted
8137 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8138 * @addrs: array for storing resulting addresses
8139 *
8140 * This function looks up addresses for array of symbols provided in
8141 * @syms array (must be alphabetically sorted) and stores them in
8142 * @addrs array, which needs to be big enough to store at least @cnt
8143 * addresses.
8144 *
8145 * This function returns 0 if all provided symbols are found,
8146 * -ESRCH otherwise.
8147 */
8148int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8149{
8150 struct kallsyms_data args;
8151 int found_all;
8152
8153 memset(addrs, 0, sizeof(*addrs) * cnt);
8154 args.addrs = addrs;
8155 args.syms = sorted_syms;
8156 args.cnt = cnt;
8157 args.found = 0;
8158
8159 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8160 if (found_all)
8161 return 0;
8162 found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8163 return found_all ? 0 : -ESRCH;
8164}
8165
8166#ifdef CONFIG_SYSCTL
8167
8168#ifdef CONFIG_DYNAMIC_FTRACE
8169static void ftrace_startup_sysctl(void)
8170{
8171 int command;
8172
8173 if (unlikely(ftrace_disabled))
8174 return;
8175
8176 /* Force update next time */
8177 saved_ftrace_func = NULL;
8178 /* ftrace_start_up is true if we want ftrace running */
8179 if (ftrace_start_up) {
8180 command = FTRACE_UPDATE_CALLS;
8181 if (ftrace_graph_active)
8182 command |= FTRACE_START_FUNC_RET;
8183 ftrace_startup_enable(command);
8184 }
8185}
8186
8187static void ftrace_shutdown_sysctl(void)
8188{
8189 int command;
8190
8191 if (unlikely(ftrace_disabled))
8192 return;
8193
8194 /* ftrace_start_up is true if ftrace is running */
8195 if (ftrace_start_up) {
8196 command = FTRACE_DISABLE_CALLS;
8197 if (ftrace_graph_active)
8198 command |= FTRACE_STOP_FUNC_RET;
8199 ftrace_run_update_code(command);
8200 }
8201}
8202#else
8203# define ftrace_startup_sysctl() do { } while (0)
8204# define ftrace_shutdown_sysctl() do { } while (0)
8205#endif /* CONFIG_DYNAMIC_FTRACE */
8206
8207static bool is_permanent_ops_registered(void)
8208{
8209 struct ftrace_ops *op;
8210
8211 do_for_each_ftrace_op(op, ftrace_ops_list) {
8212 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8213 return true;
8214 } while_for_each_ftrace_op(op);
8215
8216 return false;
8217}
8218
8219static int
8220ftrace_enable_sysctl(struct ctl_table *table, int write,
8221 void *buffer, size_t *lenp, loff_t *ppos)
8222{
8223 int ret = -ENODEV;
8224
8225 mutex_lock(&ftrace_lock);
8226
8227 if (unlikely(ftrace_disabled))
8228 goto out;
8229
8230 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8231
8232 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8233 goto out;
8234
8235 if (ftrace_enabled) {
8236
8237 /* we are starting ftrace again */
8238 if (rcu_dereference_protected(ftrace_ops_list,
8239 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8240 update_ftrace_function();
8241
8242 ftrace_startup_sysctl();
8243
8244 } else {
8245 if (is_permanent_ops_registered()) {
8246 ftrace_enabled = true;
8247 ret = -EBUSY;
8248 goto out;
8249 }
8250
8251 /* stopping ftrace calls (just send to ftrace_stub) */
8252 ftrace_trace_function = ftrace_stub;
8253
8254 ftrace_shutdown_sysctl();
8255 }
8256
8257 last_ftrace_enabled = !!ftrace_enabled;
8258 out:
8259 mutex_unlock(&ftrace_lock);
8260 return ret;
8261}
8262
8263static struct ctl_table ftrace_sysctls[] = {
8264 {
8265 .procname = "ftrace_enabled",
8266 .data = &ftrace_enabled,
8267 .maxlen = sizeof(int),
8268 .mode = 0644,
8269 .proc_handler = ftrace_enable_sysctl,
8270 },
8271 {}
8272};
8273
8274static int __init ftrace_sysctl_init(void)
8275{
8276 register_sysctl_init("kernel", ftrace_sysctls);
8277 return 0;
8278}
8279late_initcall(ftrace_sysctl_init);
8280#endif