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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 unsigned long ip = 0;
1599
1600 rcu_read_lock();
1601 rec = lookup_rec(start, end);
1602 if (rec)
1603 ip = rec->ip;
1604 rcu_read_unlock();
1605
1606 return ip;
1607}
1608
1609/**
1610 * ftrace_location - return the ftrace location
1611 * @ip: the instruction pointer to check
1612 *
1613 * Returns:
1614 * * If @ip matches the ftrace location, return @ip.
1615 * * If @ip matches sym+0, return sym's ftrace location.
1616 * * Otherwise, return 0.
1617 */
1618unsigned long ftrace_location(unsigned long ip)
1619{
1620 unsigned long loc;
1621 unsigned long offset;
1622 unsigned long size;
1623
1624 loc = ftrace_location_range(ip, ip);
1625 if (!loc) {
1626 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1627 goto out;
1628
1629 /* map sym+0 to __fentry__ */
1630 if (!offset)
1631 loc = ftrace_location_range(ip, ip + size - 1);
1632 }
1633
1634out:
1635 return loc;
1636}
1637
1638/**
1639 * ftrace_text_reserved - return true if range contains an ftrace location
1640 * @start: start of range to search
1641 * @end: end of range to search (inclusive). @end points to the last byte to check.
1642 *
1643 * Returns: 1 if @start and @end contains a ftrace location.
1644 * That is, the instruction that is either a NOP or call to
1645 * the function tracer. It checks the ftrace internal tables to
1646 * determine if the address belongs or not.
1647 */
1648int ftrace_text_reserved(const void *start, const void *end)
1649{
1650 unsigned long ret;
1651
1652 ret = ftrace_location_range((unsigned long)start,
1653 (unsigned long)end);
1654
1655 return (int)!!ret;
1656}
1657
1658/* Test if ops registered to this rec needs regs */
1659static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1660{
1661 struct ftrace_ops *ops;
1662 bool keep_regs = false;
1663
1664 for (ops = ftrace_ops_list;
1665 ops != &ftrace_list_end; ops = ops->next) {
1666 /* pass rec in as regs to have non-NULL val */
1667 if (ftrace_ops_test(ops, rec->ip, rec)) {
1668 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1669 keep_regs = true;
1670 break;
1671 }
1672 }
1673 }
1674
1675 return keep_regs;
1676}
1677
1678static struct ftrace_ops *
1679ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1680static struct ftrace_ops *
1681ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1682static struct ftrace_ops *
1683ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1684
1685static bool skip_record(struct dyn_ftrace *rec)
1686{
1687 /*
1688 * At boot up, weak functions are set to disable. Function tracing
1689 * can be enabled before they are, and they still need to be disabled now.
1690 * If the record is disabled, still continue if it is marked as already
1691 * enabled (this is needed to keep the accounting working).
1692 */
1693 return rec->flags & FTRACE_FL_DISABLED &&
1694 !(rec->flags & FTRACE_FL_ENABLED);
1695}
1696
1697static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1698 int filter_hash,
1699 bool inc)
1700{
1701 struct ftrace_hash *hash;
1702 struct ftrace_hash *other_hash;
1703 struct ftrace_page *pg;
1704 struct dyn_ftrace *rec;
1705 bool update = false;
1706 int count = 0;
1707 int all = false;
1708
1709 /* Only update if the ops has been registered */
1710 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1711 return false;
1712
1713 /*
1714 * In the filter_hash case:
1715 * If the count is zero, we update all records.
1716 * Otherwise we just update the items in the hash.
1717 *
1718 * In the notrace_hash case:
1719 * We enable the update in the hash.
1720 * As disabling notrace means enabling the tracing,
1721 * and enabling notrace means disabling, the inc variable
1722 * gets inversed.
1723 */
1724 if (filter_hash) {
1725 hash = ops->func_hash->filter_hash;
1726 other_hash = ops->func_hash->notrace_hash;
1727 if (ftrace_hash_empty(hash))
1728 all = true;
1729 } else {
1730 inc = !inc;
1731 hash = ops->func_hash->notrace_hash;
1732 other_hash = ops->func_hash->filter_hash;
1733 /*
1734 * If the notrace hash has no items,
1735 * then there's nothing to do.
1736 */
1737 if (ftrace_hash_empty(hash))
1738 return false;
1739 }
1740
1741 do_for_each_ftrace_rec(pg, rec) {
1742 int in_other_hash = 0;
1743 int in_hash = 0;
1744 int match = 0;
1745
1746 if (skip_record(rec))
1747 continue;
1748
1749 if (all) {
1750 /*
1751 * Only the filter_hash affects all records.
1752 * Update if the record is not in the notrace hash.
1753 */
1754 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1755 match = 1;
1756 } else {
1757 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1758 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1759
1760 /*
1761 * If filter_hash is set, we want to match all functions
1762 * that are in the hash but not in the other hash.
1763 *
1764 * If filter_hash is not set, then we are decrementing.
1765 * That means we match anything that is in the hash
1766 * and also in the other_hash. That is, we need to turn
1767 * off functions in the other hash because they are disabled
1768 * by this hash.
1769 */
1770 if (filter_hash && in_hash && !in_other_hash)
1771 match = 1;
1772 else if (!filter_hash && in_hash &&
1773 (in_other_hash || ftrace_hash_empty(other_hash)))
1774 match = 1;
1775 }
1776 if (!match)
1777 continue;
1778
1779 if (inc) {
1780 rec->flags++;
1781 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1782 return false;
1783
1784 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1785 rec->flags |= FTRACE_FL_DIRECT;
1786
1787 /*
1788 * If there's only a single callback registered to a
1789 * function, and the ops has a trampoline registered
1790 * for it, then we can call it directly.
1791 */
1792 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1793 rec->flags |= FTRACE_FL_TRAMP;
1794 else
1795 /*
1796 * If we are adding another function callback
1797 * to this function, and the previous had a
1798 * custom trampoline in use, then we need to go
1799 * back to the default trampoline.
1800 */
1801 rec->flags &= ~FTRACE_FL_TRAMP;
1802
1803 /*
1804 * If any ops wants regs saved for this function
1805 * then all ops will get saved regs.
1806 */
1807 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1808 rec->flags |= FTRACE_FL_REGS;
1809 } else {
1810 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1811 return false;
1812 rec->flags--;
1813
1814 /*
1815 * Only the internal direct_ops should have the
1816 * DIRECT flag set. Thus, if it is removing a
1817 * function, then that function should no longer
1818 * be direct.
1819 */
1820 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1821 rec->flags &= ~FTRACE_FL_DIRECT;
1822
1823 /*
1824 * If the rec had REGS enabled and the ops that is
1825 * being removed had REGS set, then see if there is
1826 * still any ops for this record that wants regs.
1827 * If not, we can stop recording them.
1828 */
1829 if (ftrace_rec_count(rec) > 0 &&
1830 rec->flags & FTRACE_FL_REGS &&
1831 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1832 if (!test_rec_ops_needs_regs(rec))
1833 rec->flags &= ~FTRACE_FL_REGS;
1834 }
1835
1836 /*
1837 * The TRAMP needs to be set only if rec count
1838 * is decremented to one, and the ops that is
1839 * left has a trampoline. As TRAMP can only be
1840 * enabled if there is only a single ops attached
1841 * to it.
1842 */
1843 if (ftrace_rec_count(rec) == 1 &&
1844 ftrace_find_tramp_ops_any_other(rec, ops))
1845 rec->flags |= FTRACE_FL_TRAMP;
1846 else
1847 rec->flags &= ~FTRACE_FL_TRAMP;
1848
1849 /*
1850 * flags will be cleared in ftrace_check_record()
1851 * if rec count is zero.
1852 */
1853 }
1854
1855 /*
1856 * If the rec has a single associated ops, and ops->func can be
1857 * called directly, allow the call site to call via the ops.
1858 */
1859 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1860 ftrace_rec_count(rec) == 1 &&
1861 ftrace_ops_get_func(ops) == ops->func)
1862 rec->flags |= FTRACE_FL_CALL_OPS;
1863 else
1864 rec->flags &= ~FTRACE_FL_CALL_OPS;
1865
1866 count++;
1867
1868 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1869 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1870
1871 /* Shortcut, if we handled all records, we are done. */
1872 if (!all && count == hash->count)
1873 return update;
1874 } while_for_each_ftrace_rec();
1875
1876 return update;
1877}
1878
1879static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1880 int filter_hash)
1881{
1882 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1883}
1884
1885static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1886 int filter_hash)
1887{
1888 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1889}
1890
1891static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1892 int filter_hash, int inc)
1893{
1894 struct ftrace_ops *op;
1895
1896 __ftrace_hash_rec_update(ops, filter_hash, inc);
1897
1898 if (ops->func_hash != &global_ops.local_hash)
1899 return;
1900
1901 /*
1902 * If the ops shares the global_ops hash, then we need to update
1903 * all ops that are enabled and use this hash.
1904 */
1905 do_for_each_ftrace_op(op, ftrace_ops_list) {
1906 /* Already done */
1907 if (op == ops)
1908 continue;
1909 if (op->func_hash == &global_ops.local_hash)
1910 __ftrace_hash_rec_update(op, filter_hash, inc);
1911 } while_for_each_ftrace_op(op);
1912}
1913
1914static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1915 int filter_hash)
1916{
1917 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1918}
1919
1920static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1921 int filter_hash)
1922{
1923 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1924}
1925
1926/*
1927 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1928 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1929 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1930 * Note that old_hash and new_hash has below meanings
1931 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1932 * - If the hash is EMPTY_HASH, it hits nothing
1933 * - Anything else hits the recs which match the hash entries.
1934 *
1935 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1936 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1937 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1938 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1939 * the return value to the caller and eventually to the owner of the DIRECT
1940 * ops.
1941 */
1942static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1943 struct ftrace_hash *old_hash,
1944 struct ftrace_hash *new_hash)
1945{
1946 struct ftrace_page *pg;
1947 struct dyn_ftrace *rec, *end = NULL;
1948 int in_old, in_new;
1949 bool is_ipmodify, is_direct;
1950
1951 /* Only update if the ops has been registered */
1952 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1953 return 0;
1954
1955 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1956 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1957
1958 /* neither IPMODIFY nor DIRECT, skip */
1959 if (!is_ipmodify && !is_direct)
1960 return 0;
1961
1962 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1963 return 0;
1964
1965 /*
1966 * Since the IPMODIFY and DIRECT are very address sensitive
1967 * actions, we do not allow ftrace_ops to set all functions to new
1968 * hash.
1969 */
1970 if (!new_hash || !old_hash)
1971 return -EINVAL;
1972
1973 /* Update rec->flags */
1974 do_for_each_ftrace_rec(pg, rec) {
1975
1976 if (rec->flags & FTRACE_FL_DISABLED)
1977 continue;
1978
1979 /* We need to update only differences of filter_hash */
1980 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1981 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1982 if (in_old == in_new)
1983 continue;
1984
1985 if (in_new) {
1986 if (rec->flags & FTRACE_FL_IPMODIFY) {
1987 int ret;
1988
1989 /* Cannot have two ipmodify on same rec */
1990 if (is_ipmodify)
1991 goto rollback;
1992
1993 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1994
1995 /*
1996 * Another ops with IPMODIFY is already
1997 * attached. We are now attaching a direct
1998 * ops. Run SHARE_IPMODIFY_SELF, to check
1999 * whether sharing is supported.
2000 */
2001 if (!ops->ops_func)
2002 return -EBUSY;
2003 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2004 if (ret)
2005 return ret;
2006 } else if (is_ipmodify) {
2007 rec->flags |= FTRACE_FL_IPMODIFY;
2008 }
2009 } else if (is_ipmodify) {
2010 rec->flags &= ~FTRACE_FL_IPMODIFY;
2011 }
2012 } while_for_each_ftrace_rec();
2013
2014 return 0;
2015
2016rollback:
2017 end = rec;
2018
2019 /* Roll back what we did above */
2020 do_for_each_ftrace_rec(pg, rec) {
2021
2022 if (rec->flags & FTRACE_FL_DISABLED)
2023 continue;
2024
2025 if (rec == end)
2026 goto err_out;
2027
2028 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2029 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2030 if (in_old == in_new)
2031 continue;
2032
2033 if (in_new)
2034 rec->flags &= ~FTRACE_FL_IPMODIFY;
2035 else
2036 rec->flags |= FTRACE_FL_IPMODIFY;
2037 } while_for_each_ftrace_rec();
2038
2039err_out:
2040 return -EBUSY;
2041}
2042
2043static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2044{
2045 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2046
2047 if (ftrace_hash_empty(hash))
2048 hash = NULL;
2049
2050 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2051}
2052
2053/* Disabling always succeeds */
2054static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2055{
2056 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2057
2058 if (ftrace_hash_empty(hash))
2059 hash = NULL;
2060
2061 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2062}
2063
2064static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2065 struct ftrace_hash *new_hash)
2066{
2067 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2068
2069 if (ftrace_hash_empty(old_hash))
2070 old_hash = NULL;
2071
2072 if (ftrace_hash_empty(new_hash))
2073 new_hash = NULL;
2074
2075 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2076}
2077
2078static void print_ip_ins(const char *fmt, const unsigned char *p)
2079{
2080 char ins[MCOUNT_INSN_SIZE];
2081
2082 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2083 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2084 return;
2085 }
2086
2087 printk(KERN_CONT "%s", fmt);
2088 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2089}
2090
2091enum ftrace_bug_type ftrace_bug_type;
2092const void *ftrace_expected;
2093
2094static void print_bug_type(void)
2095{
2096 switch (ftrace_bug_type) {
2097 case FTRACE_BUG_UNKNOWN:
2098 break;
2099 case FTRACE_BUG_INIT:
2100 pr_info("Initializing ftrace call sites\n");
2101 break;
2102 case FTRACE_BUG_NOP:
2103 pr_info("Setting ftrace call site to NOP\n");
2104 break;
2105 case FTRACE_BUG_CALL:
2106 pr_info("Setting ftrace call site to call ftrace function\n");
2107 break;
2108 case FTRACE_BUG_UPDATE:
2109 pr_info("Updating ftrace call site to call a different ftrace function\n");
2110 break;
2111 }
2112}
2113
2114/**
2115 * ftrace_bug - report and shutdown function tracer
2116 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2117 * @rec: The record that failed
2118 *
2119 * The arch code that enables or disables the function tracing
2120 * can call ftrace_bug() when it has detected a problem in
2121 * modifying the code. @failed should be one of either:
2122 * EFAULT - if the problem happens on reading the @ip address
2123 * EINVAL - if what is read at @ip is not what was expected
2124 * EPERM - if the problem happens on writing to the @ip address
2125 */
2126void ftrace_bug(int failed, struct dyn_ftrace *rec)
2127{
2128 unsigned long ip = rec ? rec->ip : 0;
2129
2130 pr_info("------------[ ftrace bug ]------------\n");
2131
2132 switch (failed) {
2133 case -EFAULT:
2134 pr_info("ftrace faulted on modifying ");
2135 print_ip_sym(KERN_INFO, ip);
2136 break;
2137 case -EINVAL:
2138 pr_info("ftrace failed to modify ");
2139 print_ip_sym(KERN_INFO, ip);
2140 print_ip_ins(" actual: ", (unsigned char *)ip);
2141 pr_cont("\n");
2142 if (ftrace_expected) {
2143 print_ip_ins(" expected: ", ftrace_expected);
2144 pr_cont("\n");
2145 }
2146 break;
2147 case -EPERM:
2148 pr_info("ftrace faulted on writing ");
2149 print_ip_sym(KERN_INFO, ip);
2150 break;
2151 default:
2152 pr_info("ftrace faulted on unknown error ");
2153 print_ip_sym(KERN_INFO, ip);
2154 }
2155 print_bug_type();
2156 if (rec) {
2157 struct ftrace_ops *ops = NULL;
2158
2159 pr_info("ftrace record flags: %lx\n", rec->flags);
2160 pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2161 rec->flags & FTRACE_FL_REGS ? " R" : " ",
2162 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ");
2163 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2164 ops = ftrace_find_tramp_ops_any(rec);
2165 if (ops) {
2166 do {
2167 pr_cont("\ttramp: %pS (%pS)",
2168 (void *)ops->trampoline,
2169 (void *)ops->func);
2170 ops = ftrace_find_tramp_ops_next(rec, ops);
2171 } while (ops);
2172 } else
2173 pr_cont("\ttramp: ERROR!");
2174
2175 }
2176 ip = ftrace_get_addr_curr(rec);
2177 pr_cont("\n expected tramp: %lx\n", ip);
2178 }
2179
2180 FTRACE_WARN_ON_ONCE(1);
2181}
2182
2183static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2184{
2185 unsigned long flag = 0UL;
2186
2187 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2188
2189 if (skip_record(rec))
2190 return FTRACE_UPDATE_IGNORE;
2191
2192 /*
2193 * If we are updating calls:
2194 *
2195 * If the record has a ref count, then we need to enable it
2196 * because someone is using it.
2197 *
2198 * Otherwise we make sure its disabled.
2199 *
2200 * If we are disabling calls, then disable all records that
2201 * are enabled.
2202 */
2203 if (enable && ftrace_rec_count(rec))
2204 flag = FTRACE_FL_ENABLED;
2205
2206 /*
2207 * If enabling and the REGS flag does not match the REGS_EN, or
2208 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2209 * this record. Set flags to fail the compare against ENABLED.
2210 * Same for direct calls.
2211 */
2212 if (flag) {
2213 if (!(rec->flags & FTRACE_FL_REGS) !=
2214 !(rec->flags & FTRACE_FL_REGS_EN))
2215 flag |= FTRACE_FL_REGS;
2216
2217 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2218 !(rec->flags & FTRACE_FL_TRAMP_EN))
2219 flag |= FTRACE_FL_TRAMP;
2220
2221 /*
2222 * Direct calls are special, as count matters.
2223 * We must test the record for direct, if the
2224 * DIRECT and DIRECT_EN do not match, but only
2225 * if the count is 1. That's because, if the
2226 * count is something other than one, we do not
2227 * want the direct enabled (it will be done via the
2228 * direct helper). But if DIRECT_EN is set, and
2229 * the count is not one, we need to clear it.
2230 *
2231 */
2232 if (ftrace_rec_count(rec) == 1) {
2233 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2234 !(rec->flags & FTRACE_FL_DIRECT_EN))
2235 flag |= FTRACE_FL_DIRECT;
2236 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2237 flag |= FTRACE_FL_DIRECT;
2238 }
2239
2240 /*
2241 * Ops calls are special, as count matters.
2242 * As with direct calls, they must only be enabled when count
2243 * is one, otherwise they'll be handled via the list ops.
2244 */
2245 if (ftrace_rec_count(rec) == 1) {
2246 if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2247 !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2248 flag |= FTRACE_FL_CALL_OPS;
2249 } else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2250 flag |= FTRACE_FL_CALL_OPS;
2251 }
2252 }
2253
2254 /* If the state of this record hasn't changed, then do nothing */
2255 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2256 return FTRACE_UPDATE_IGNORE;
2257
2258 if (flag) {
2259 /* Save off if rec is being enabled (for return value) */
2260 flag ^= rec->flags & FTRACE_FL_ENABLED;
2261
2262 if (update) {
2263 rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2264 if (flag & FTRACE_FL_REGS) {
2265 if (rec->flags & FTRACE_FL_REGS)
2266 rec->flags |= FTRACE_FL_REGS_EN;
2267 else
2268 rec->flags &= ~FTRACE_FL_REGS_EN;
2269 }
2270 if (flag & FTRACE_FL_TRAMP) {
2271 if (rec->flags & FTRACE_FL_TRAMP)
2272 rec->flags |= FTRACE_FL_TRAMP_EN;
2273 else
2274 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2275 }
2276
2277 /* Keep track of anything that modifies the function */
2278 if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2279 rec->flags |= FTRACE_FL_MODIFIED;
2280
2281 if (flag & FTRACE_FL_DIRECT) {
2282 /*
2283 * If there's only one user (direct_ops helper)
2284 * then we can call the direct function
2285 * directly (no ftrace trampoline).
2286 */
2287 if (ftrace_rec_count(rec) == 1) {
2288 if (rec->flags & FTRACE_FL_DIRECT)
2289 rec->flags |= FTRACE_FL_DIRECT_EN;
2290 else
2291 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2292 } else {
2293 /*
2294 * Can only call directly if there's
2295 * only one callback to the function.
2296 */
2297 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2298 }
2299 }
2300
2301 if (flag & FTRACE_FL_CALL_OPS) {
2302 if (ftrace_rec_count(rec) == 1) {
2303 if (rec->flags & FTRACE_FL_CALL_OPS)
2304 rec->flags |= FTRACE_FL_CALL_OPS_EN;
2305 else
2306 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2307 } else {
2308 /*
2309 * Can only call directly if there's
2310 * only one set of associated ops.
2311 */
2312 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2313 }
2314 }
2315 }
2316
2317 /*
2318 * If this record is being updated from a nop, then
2319 * return UPDATE_MAKE_CALL.
2320 * Otherwise,
2321 * return UPDATE_MODIFY_CALL to tell the caller to convert
2322 * from the save regs, to a non-save regs function or
2323 * vice versa, or from a trampoline call.
2324 */
2325 if (flag & FTRACE_FL_ENABLED) {
2326 ftrace_bug_type = FTRACE_BUG_CALL;
2327 return FTRACE_UPDATE_MAKE_CALL;
2328 }
2329
2330 ftrace_bug_type = FTRACE_BUG_UPDATE;
2331 return FTRACE_UPDATE_MODIFY_CALL;
2332 }
2333
2334 if (update) {
2335 /* If there's no more users, clear all flags */
2336 if (!ftrace_rec_count(rec))
2337 rec->flags &= FTRACE_NOCLEAR_FLAGS;
2338 else
2339 /*
2340 * Just disable the record, but keep the ops TRAMP
2341 * and REGS states. The _EN flags must be disabled though.
2342 */
2343 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2344 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2345 FTRACE_FL_CALL_OPS_EN);
2346 }
2347
2348 ftrace_bug_type = FTRACE_BUG_NOP;
2349 return FTRACE_UPDATE_MAKE_NOP;
2350}
2351
2352/**
2353 * ftrace_update_record - set a record that now is tracing or not
2354 * @rec: the record to update
2355 * @enable: set to true if the record is tracing, false to force disable
2356 *
2357 * The records that represent all functions that can be traced need
2358 * to be updated when tracing has been enabled.
2359 */
2360int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2361{
2362 return ftrace_check_record(rec, enable, true);
2363}
2364
2365/**
2366 * ftrace_test_record - check if the record has been enabled or not
2367 * @rec: the record to test
2368 * @enable: set to true to check if enabled, false if it is disabled
2369 *
2370 * The arch code may need to test if a record is already set to
2371 * tracing to determine how to modify the function code that it
2372 * represents.
2373 */
2374int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2375{
2376 return ftrace_check_record(rec, enable, false);
2377}
2378
2379static struct ftrace_ops *
2380ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2381{
2382 struct ftrace_ops *op;
2383 unsigned long ip = rec->ip;
2384
2385 do_for_each_ftrace_op(op, ftrace_ops_list) {
2386
2387 if (!op->trampoline)
2388 continue;
2389
2390 if (hash_contains_ip(ip, op->func_hash))
2391 return op;
2392 } while_for_each_ftrace_op(op);
2393
2394 return NULL;
2395}
2396
2397static struct ftrace_ops *
2398ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2399{
2400 struct ftrace_ops *op;
2401 unsigned long ip = rec->ip;
2402
2403 do_for_each_ftrace_op(op, ftrace_ops_list) {
2404
2405 if (op == op_exclude || !op->trampoline)
2406 continue;
2407
2408 if (hash_contains_ip(ip, op->func_hash))
2409 return op;
2410 } while_for_each_ftrace_op(op);
2411
2412 return NULL;
2413}
2414
2415static struct ftrace_ops *
2416ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2417 struct ftrace_ops *op)
2418{
2419 unsigned long ip = rec->ip;
2420
2421 while_for_each_ftrace_op(op) {
2422
2423 if (!op->trampoline)
2424 continue;
2425
2426 if (hash_contains_ip(ip, op->func_hash))
2427 return op;
2428 }
2429
2430 return NULL;
2431}
2432
2433static struct ftrace_ops *
2434ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2435{
2436 struct ftrace_ops *op;
2437 unsigned long ip = rec->ip;
2438
2439 /*
2440 * Need to check removed ops first.
2441 * If they are being removed, and this rec has a tramp,
2442 * and this rec is in the ops list, then it would be the
2443 * one with the tramp.
2444 */
2445 if (removed_ops) {
2446 if (hash_contains_ip(ip, &removed_ops->old_hash))
2447 return removed_ops;
2448 }
2449
2450 /*
2451 * Need to find the current trampoline for a rec.
2452 * Now, a trampoline is only attached to a rec if there
2453 * was a single 'ops' attached to it. But this can be called
2454 * when we are adding another op to the rec or removing the
2455 * current one. Thus, if the op is being added, we can
2456 * ignore it because it hasn't attached itself to the rec
2457 * yet.
2458 *
2459 * If an ops is being modified (hooking to different functions)
2460 * then we don't care about the new functions that are being
2461 * added, just the old ones (that are probably being removed).
2462 *
2463 * If we are adding an ops to a function that already is using
2464 * a trampoline, it needs to be removed (trampolines are only
2465 * for single ops connected), then an ops that is not being
2466 * modified also needs to be checked.
2467 */
2468 do_for_each_ftrace_op(op, ftrace_ops_list) {
2469
2470 if (!op->trampoline)
2471 continue;
2472
2473 /*
2474 * If the ops is being added, it hasn't gotten to
2475 * the point to be removed from this tree yet.
2476 */
2477 if (op->flags & FTRACE_OPS_FL_ADDING)
2478 continue;
2479
2480
2481 /*
2482 * If the ops is being modified and is in the old
2483 * hash, then it is probably being removed from this
2484 * function.
2485 */
2486 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2487 hash_contains_ip(ip, &op->old_hash))
2488 return op;
2489 /*
2490 * If the ops is not being added or modified, and it's
2491 * in its normal filter hash, then this must be the one
2492 * we want!
2493 */
2494 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2495 hash_contains_ip(ip, op->func_hash))
2496 return op;
2497
2498 } while_for_each_ftrace_op(op);
2499
2500 return NULL;
2501}
2502
2503static struct ftrace_ops *
2504ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2505{
2506 struct ftrace_ops *op;
2507 unsigned long ip = rec->ip;
2508
2509 do_for_each_ftrace_op(op, ftrace_ops_list) {
2510 /* pass rec in as regs to have non-NULL val */
2511 if (hash_contains_ip(ip, op->func_hash))
2512 return op;
2513 } while_for_each_ftrace_op(op);
2514
2515 return NULL;
2516}
2517
2518struct ftrace_ops *
2519ftrace_find_unique_ops(struct dyn_ftrace *rec)
2520{
2521 struct ftrace_ops *op, *found = NULL;
2522 unsigned long ip = rec->ip;
2523
2524 do_for_each_ftrace_op(op, ftrace_ops_list) {
2525
2526 if (hash_contains_ip(ip, op->func_hash)) {
2527 if (found)
2528 return NULL;
2529 found = op;
2530 }
2531
2532 } while_for_each_ftrace_op(op);
2533
2534 return found;
2535}
2536
2537#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2538/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2539static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
2540static DEFINE_MUTEX(direct_mutex);
2541int ftrace_direct_func_count;
2542
2543/*
2544 * Search the direct_functions hash to see if the given instruction pointer
2545 * has a direct caller attached to it.
2546 */
2547unsigned long ftrace_find_rec_direct(unsigned long ip)
2548{
2549 struct ftrace_func_entry *entry;
2550
2551 entry = __ftrace_lookup_ip(direct_functions, ip);
2552 if (!entry)
2553 return 0;
2554
2555 return entry->direct;
2556}
2557
2558static void call_direct_funcs(unsigned long ip, unsigned long pip,
2559 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2560{
2561 unsigned long addr = READ_ONCE(ops->direct_call);
2562
2563 if (!addr)
2564 return;
2565
2566 arch_ftrace_set_direct_caller(fregs, addr);
2567}
2568#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2569
2570/**
2571 * ftrace_get_addr_new - Get the call address to set to
2572 * @rec: The ftrace record descriptor
2573 *
2574 * If the record has the FTRACE_FL_REGS set, that means that it
2575 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2576 * is not set, then it wants to convert to the normal callback.
2577 *
2578 * Returns: the address of the trampoline to set to
2579 */
2580unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2581{
2582 struct ftrace_ops *ops;
2583 unsigned long addr;
2584
2585 if ((rec->flags & FTRACE_FL_DIRECT) &&
2586 (ftrace_rec_count(rec) == 1)) {
2587 addr = ftrace_find_rec_direct(rec->ip);
2588 if (addr)
2589 return addr;
2590 WARN_ON_ONCE(1);
2591 }
2592
2593 /* Trampolines take precedence over regs */
2594 if (rec->flags & FTRACE_FL_TRAMP) {
2595 ops = ftrace_find_tramp_ops_new(rec);
2596 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2597 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2598 (void *)rec->ip, (void *)rec->ip, rec->flags);
2599 /* Ftrace is shutting down, return anything */
2600 return (unsigned long)FTRACE_ADDR;
2601 }
2602 return ops->trampoline;
2603 }
2604
2605 if (rec->flags & FTRACE_FL_REGS)
2606 return (unsigned long)FTRACE_REGS_ADDR;
2607 else
2608 return (unsigned long)FTRACE_ADDR;
2609}
2610
2611/**
2612 * ftrace_get_addr_curr - Get the call address that is already there
2613 * @rec: The ftrace record descriptor
2614 *
2615 * The FTRACE_FL_REGS_EN is set when the record already points to
2616 * a function that saves all the regs. Basically the '_EN' version
2617 * represents the current state of the function.
2618 *
2619 * Returns: the address of the trampoline that is currently being called
2620 */
2621unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2622{
2623 struct ftrace_ops *ops;
2624 unsigned long addr;
2625
2626 /* Direct calls take precedence over trampolines */
2627 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2628 addr = ftrace_find_rec_direct(rec->ip);
2629 if (addr)
2630 return addr;
2631 WARN_ON_ONCE(1);
2632 }
2633
2634 /* Trampolines take precedence over regs */
2635 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2636 ops = ftrace_find_tramp_ops_curr(rec);
2637 if (FTRACE_WARN_ON(!ops)) {
2638 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2639 (void *)rec->ip, (void *)rec->ip);
2640 /* Ftrace is shutting down, return anything */
2641 return (unsigned long)FTRACE_ADDR;
2642 }
2643 return ops->trampoline;
2644 }
2645
2646 if (rec->flags & FTRACE_FL_REGS_EN)
2647 return (unsigned long)FTRACE_REGS_ADDR;
2648 else
2649 return (unsigned long)FTRACE_ADDR;
2650}
2651
2652static int
2653__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2654{
2655 unsigned long ftrace_old_addr;
2656 unsigned long ftrace_addr;
2657 int ret;
2658
2659 ftrace_addr = ftrace_get_addr_new(rec);
2660
2661 /* This needs to be done before we call ftrace_update_record */
2662 ftrace_old_addr = ftrace_get_addr_curr(rec);
2663
2664 ret = ftrace_update_record(rec, enable);
2665
2666 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2667
2668 switch (ret) {
2669 case FTRACE_UPDATE_IGNORE:
2670 return 0;
2671
2672 case FTRACE_UPDATE_MAKE_CALL:
2673 ftrace_bug_type = FTRACE_BUG_CALL;
2674 return ftrace_make_call(rec, ftrace_addr);
2675
2676 case FTRACE_UPDATE_MAKE_NOP:
2677 ftrace_bug_type = FTRACE_BUG_NOP;
2678 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2679
2680 case FTRACE_UPDATE_MODIFY_CALL:
2681 ftrace_bug_type = FTRACE_BUG_UPDATE;
2682 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2683 }
2684
2685 return -1; /* unknown ftrace bug */
2686}
2687
2688void __weak ftrace_replace_code(int mod_flags)
2689{
2690 struct dyn_ftrace *rec;
2691 struct ftrace_page *pg;
2692 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2693 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2694 int failed;
2695
2696 if (unlikely(ftrace_disabled))
2697 return;
2698
2699 do_for_each_ftrace_rec(pg, rec) {
2700
2701 if (skip_record(rec))
2702 continue;
2703
2704 failed = __ftrace_replace_code(rec, enable);
2705 if (failed) {
2706 ftrace_bug(failed, rec);
2707 /* Stop processing */
2708 return;
2709 }
2710 if (schedulable)
2711 cond_resched();
2712 } while_for_each_ftrace_rec();
2713}
2714
2715struct ftrace_rec_iter {
2716 struct ftrace_page *pg;
2717 int index;
2718};
2719
2720/**
2721 * ftrace_rec_iter_start - start up iterating over traced functions
2722 *
2723 * Returns: an iterator handle that is used to iterate over all
2724 * the records that represent address locations where functions
2725 * are traced.
2726 *
2727 * May return NULL if no records are available.
2728 */
2729struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2730{
2731 /*
2732 * We only use a single iterator.
2733 * Protected by the ftrace_lock mutex.
2734 */
2735 static struct ftrace_rec_iter ftrace_rec_iter;
2736 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2737
2738 iter->pg = ftrace_pages_start;
2739 iter->index = 0;
2740
2741 /* Could have empty pages */
2742 while (iter->pg && !iter->pg->index)
2743 iter->pg = iter->pg->next;
2744
2745 if (!iter->pg)
2746 return NULL;
2747
2748 return iter;
2749}
2750
2751/**
2752 * ftrace_rec_iter_next - get the next record to process.
2753 * @iter: The handle to the iterator.
2754 *
2755 * Returns: the next iterator after the given iterator @iter.
2756 */
2757struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2758{
2759 iter->index++;
2760
2761 if (iter->index >= iter->pg->index) {
2762 iter->pg = iter->pg->next;
2763 iter->index = 0;
2764
2765 /* Could have empty pages */
2766 while (iter->pg && !iter->pg->index)
2767 iter->pg = iter->pg->next;
2768 }
2769
2770 if (!iter->pg)
2771 return NULL;
2772
2773 return iter;
2774}
2775
2776/**
2777 * ftrace_rec_iter_record - get the record at the iterator location
2778 * @iter: The current iterator location
2779 *
2780 * Returns: the record that the current @iter is at.
2781 */
2782struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2783{
2784 return &iter->pg->records[iter->index];
2785}
2786
2787static int
2788ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2789{
2790 int ret;
2791
2792 if (unlikely(ftrace_disabled))
2793 return 0;
2794
2795 ret = ftrace_init_nop(mod, rec);
2796 if (ret) {
2797 ftrace_bug_type = FTRACE_BUG_INIT;
2798 ftrace_bug(ret, rec);
2799 return 0;
2800 }
2801 return 1;
2802}
2803
2804/*
2805 * archs can override this function if they must do something
2806 * before the modifying code is performed.
2807 */
2808void __weak ftrace_arch_code_modify_prepare(void)
2809{
2810}
2811
2812/*
2813 * archs can override this function if they must do something
2814 * after the modifying code is performed.
2815 */
2816void __weak ftrace_arch_code_modify_post_process(void)
2817{
2818}
2819
2820static int update_ftrace_func(ftrace_func_t func)
2821{
2822 static ftrace_func_t save_func;
2823
2824 /* Avoid updating if it hasn't changed */
2825 if (func == save_func)
2826 return 0;
2827
2828 save_func = func;
2829
2830 return ftrace_update_ftrace_func(func);
2831}
2832
2833void ftrace_modify_all_code(int command)
2834{
2835 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2836 int mod_flags = 0;
2837 int err = 0;
2838
2839 if (command & FTRACE_MAY_SLEEP)
2840 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2841
2842 /*
2843 * If the ftrace_caller calls a ftrace_ops func directly,
2844 * we need to make sure that it only traces functions it
2845 * expects to trace. When doing the switch of functions,
2846 * we need to update to the ftrace_ops_list_func first
2847 * before the transition between old and new calls are set,
2848 * as the ftrace_ops_list_func will check the ops hashes
2849 * to make sure the ops are having the right functions
2850 * traced.
2851 */
2852 if (update) {
2853 err = update_ftrace_func(ftrace_ops_list_func);
2854 if (FTRACE_WARN_ON(err))
2855 return;
2856 }
2857
2858 if (command & FTRACE_UPDATE_CALLS)
2859 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2860 else if (command & FTRACE_DISABLE_CALLS)
2861 ftrace_replace_code(mod_flags);
2862
2863 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2864 function_trace_op = set_function_trace_op;
2865 smp_wmb();
2866 /* If irqs are disabled, we are in stop machine */
2867 if (!irqs_disabled())
2868 smp_call_function(ftrace_sync_ipi, NULL, 1);
2869 err = update_ftrace_func(ftrace_trace_function);
2870 if (FTRACE_WARN_ON(err))
2871 return;
2872 }
2873
2874 if (command & FTRACE_START_FUNC_RET)
2875 err = ftrace_enable_ftrace_graph_caller();
2876 else if (command & FTRACE_STOP_FUNC_RET)
2877 err = ftrace_disable_ftrace_graph_caller();
2878 FTRACE_WARN_ON(err);
2879}
2880
2881static int __ftrace_modify_code(void *data)
2882{
2883 int *command = data;
2884
2885 ftrace_modify_all_code(*command);
2886
2887 return 0;
2888}
2889
2890/**
2891 * ftrace_run_stop_machine - go back to the stop machine method
2892 * @command: The command to tell ftrace what to do
2893 *
2894 * If an arch needs to fall back to the stop machine method, the
2895 * it can call this function.
2896 */
2897void ftrace_run_stop_machine(int command)
2898{
2899 stop_machine(__ftrace_modify_code, &command, NULL);
2900}
2901
2902/**
2903 * arch_ftrace_update_code - modify the code to trace or not trace
2904 * @command: The command that needs to be done
2905 *
2906 * Archs can override this function if it does not need to
2907 * run stop_machine() to modify code.
2908 */
2909void __weak arch_ftrace_update_code(int command)
2910{
2911 ftrace_run_stop_machine(command);
2912}
2913
2914static void ftrace_run_update_code(int command)
2915{
2916 ftrace_arch_code_modify_prepare();
2917
2918 /*
2919 * By default we use stop_machine() to modify the code.
2920 * But archs can do what ever they want as long as it
2921 * is safe. The stop_machine() is the safest, but also
2922 * produces the most overhead.
2923 */
2924 arch_ftrace_update_code(command);
2925
2926 ftrace_arch_code_modify_post_process();
2927}
2928
2929static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2930 struct ftrace_ops_hash *old_hash)
2931{
2932 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2933 ops->old_hash.filter_hash = old_hash->filter_hash;
2934 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2935 ftrace_run_update_code(command);
2936 ops->old_hash.filter_hash = NULL;
2937 ops->old_hash.notrace_hash = NULL;
2938 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2939}
2940
2941static ftrace_func_t saved_ftrace_func;
2942static int ftrace_start_up;
2943
2944void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2945{
2946}
2947
2948/* List of trace_ops that have allocated trampolines */
2949static LIST_HEAD(ftrace_ops_trampoline_list);
2950
2951static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2952{
2953 lockdep_assert_held(&ftrace_lock);
2954 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2955}
2956
2957static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2958{
2959 lockdep_assert_held(&ftrace_lock);
2960 list_del_rcu(&ops->list);
2961 synchronize_rcu();
2962}
2963
2964/*
2965 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2966 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2967 * not a module.
2968 */
2969#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2970#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2971
2972static void ftrace_trampoline_free(struct ftrace_ops *ops)
2973{
2974 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2975 ops->trampoline) {
2976 /*
2977 * Record the text poke event before the ksymbol unregister
2978 * event.
2979 */
2980 perf_event_text_poke((void *)ops->trampoline,
2981 (void *)ops->trampoline,
2982 ops->trampoline_size, NULL, 0);
2983 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2984 ops->trampoline, ops->trampoline_size,
2985 true, FTRACE_TRAMPOLINE_SYM);
2986 /* Remove from kallsyms after the perf events */
2987 ftrace_remove_trampoline_from_kallsyms(ops);
2988 }
2989
2990 arch_ftrace_trampoline_free(ops);
2991}
2992
2993static void ftrace_startup_enable(int command)
2994{
2995 if (saved_ftrace_func != ftrace_trace_function) {
2996 saved_ftrace_func = ftrace_trace_function;
2997 command |= FTRACE_UPDATE_TRACE_FUNC;
2998 }
2999
3000 if (!command || !ftrace_enabled)
3001 return;
3002
3003 ftrace_run_update_code(command);
3004}
3005
3006static void ftrace_startup_all(int command)
3007{
3008 update_all_ops = true;
3009 ftrace_startup_enable(command);
3010 update_all_ops = false;
3011}
3012
3013int ftrace_startup(struct ftrace_ops *ops, int command)
3014{
3015 int ret;
3016
3017 if (unlikely(ftrace_disabled))
3018 return -ENODEV;
3019
3020 ret = __register_ftrace_function(ops);
3021 if (ret)
3022 return ret;
3023
3024 ftrace_start_up++;
3025
3026 /*
3027 * Note that ftrace probes uses this to start up
3028 * and modify functions it will probe. But we still
3029 * set the ADDING flag for modification, as probes
3030 * do not have trampolines. If they add them in the
3031 * future, then the probes will need to distinguish
3032 * between adding and updating probes.
3033 */
3034 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3035
3036 ret = ftrace_hash_ipmodify_enable(ops);
3037 if (ret < 0) {
3038 /* Rollback registration process */
3039 __unregister_ftrace_function(ops);
3040 ftrace_start_up--;
3041 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3042 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3043 ftrace_trampoline_free(ops);
3044 return ret;
3045 }
3046
3047 if (ftrace_hash_rec_enable(ops, 1))
3048 command |= FTRACE_UPDATE_CALLS;
3049
3050 ftrace_startup_enable(command);
3051
3052 /*
3053 * If ftrace is in an undefined state, we just remove ops from list
3054 * to prevent the NULL pointer, instead of totally rolling it back and
3055 * free trampoline, because those actions could cause further damage.
3056 */
3057 if (unlikely(ftrace_disabled)) {
3058 __unregister_ftrace_function(ops);
3059 return -ENODEV;
3060 }
3061
3062 ops->flags &= ~FTRACE_OPS_FL_ADDING;
3063
3064 return 0;
3065}
3066
3067int ftrace_shutdown(struct ftrace_ops *ops, int command)
3068{
3069 int ret;
3070
3071 if (unlikely(ftrace_disabled))
3072 return -ENODEV;
3073
3074 ret = __unregister_ftrace_function(ops);
3075 if (ret)
3076 return ret;
3077
3078 ftrace_start_up--;
3079 /*
3080 * Just warn in case of unbalance, no need to kill ftrace, it's not
3081 * critical but the ftrace_call callers may be never nopped again after
3082 * further ftrace uses.
3083 */
3084 WARN_ON_ONCE(ftrace_start_up < 0);
3085
3086 /* Disabling ipmodify never fails */
3087 ftrace_hash_ipmodify_disable(ops);
3088
3089 if (ftrace_hash_rec_disable(ops, 1))
3090 command |= FTRACE_UPDATE_CALLS;
3091
3092 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3093
3094 if (saved_ftrace_func != ftrace_trace_function) {
3095 saved_ftrace_func = ftrace_trace_function;
3096 command |= FTRACE_UPDATE_TRACE_FUNC;
3097 }
3098
3099 if (!command || !ftrace_enabled)
3100 goto out;
3101
3102 /*
3103 * If the ops uses a trampoline, then it needs to be
3104 * tested first on update.
3105 */
3106 ops->flags |= FTRACE_OPS_FL_REMOVING;
3107 removed_ops = ops;
3108
3109 /* The trampoline logic checks the old hashes */
3110 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3111 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3112
3113 ftrace_run_update_code(command);
3114
3115 /*
3116 * If there's no more ops registered with ftrace, run a
3117 * sanity check to make sure all rec flags are cleared.
3118 */
3119 if (rcu_dereference_protected(ftrace_ops_list,
3120 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3121 struct ftrace_page *pg;
3122 struct dyn_ftrace *rec;
3123
3124 do_for_each_ftrace_rec(pg, rec) {
3125 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3126 pr_warn(" %pS flags:%lx\n",
3127 (void *)rec->ip, rec->flags);
3128 } while_for_each_ftrace_rec();
3129 }
3130
3131 ops->old_hash.filter_hash = NULL;
3132 ops->old_hash.notrace_hash = NULL;
3133
3134 removed_ops = NULL;
3135 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3136
3137out:
3138 /*
3139 * Dynamic ops may be freed, we must make sure that all
3140 * callers are done before leaving this function.
3141 */
3142 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3143 /*
3144 * We need to do a hard force of sched synchronization.
3145 * This is because we use preempt_disable() to do RCU, but
3146 * the function tracers can be called where RCU is not watching
3147 * (like before user_exit()). We can not rely on the RCU
3148 * infrastructure to do the synchronization, thus we must do it
3149 * ourselves.
3150 */
3151 synchronize_rcu_tasks_rude();
3152
3153 /*
3154 * When the kernel is preemptive, tasks can be preempted
3155 * while on a ftrace trampoline. Just scheduling a task on
3156 * a CPU is not good enough to flush them. Calling
3157 * synchronize_rcu_tasks() will wait for those tasks to
3158 * execute and either schedule voluntarily or enter user space.
3159 */
3160 if (IS_ENABLED(CONFIG_PREEMPTION))
3161 synchronize_rcu_tasks();
3162
3163 ftrace_trampoline_free(ops);
3164 }
3165
3166 return 0;
3167}
3168
3169static u64 ftrace_update_time;
3170unsigned long ftrace_update_tot_cnt;
3171unsigned long ftrace_number_of_pages;
3172unsigned long ftrace_number_of_groups;
3173
3174static inline int ops_traces_mod(struct ftrace_ops *ops)
3175{
3176 /*
3177 * Filter_hash being empty will default to trace module.
3178 * But notrace hash requires a test of individual module functions.
3179 */
3180 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3181 ftrace_hash_empty(ops->func_hash->notrace_hash);
3182}
3183
3184static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3185{
3186 bool init_nop = ftrace_need_init_nop();
3187 struct ftrace_page *pg;
3188 struct dyn_ftrace *p;
3189 u64 start, stop;
3190 unsigned long update_cnt = 0;
3191 unsigned long rec_flags = 0;
3192 int i;
3193
3194 start = ftrace_now(raw_smp_processor_id());
3195
3196 /*
3197 * When a module is loaded, this function is called to convert
3198 * the calls to mcount in its text to nops, and also to create
3199 * an entry in the ftrace data. Now, if ftrace is activated
3200 * after this call, but before the module sets its text to
3201 * read-only, the modification of enabling ftrace can fail if
3202 * the read-only is done while ftrace is converting the calls.
3203 * To prevent this, the module's records are set as disabled
3204 * and will be enabled after the call to set the module's text
3205 * to read-only.
3206 */
3207 if (mod)
3208 rec_flags |= FTRACE_FL_DISABLED;
3209
3210 for (pg = new_pgs; pg; pg = pg->next) {
3211
3212 for (i = 0; i < pg->index; i++) {
3213
3214 /* If something went wrong, bail without enabling anything */
3215 if (unlikely(ftrace_disabled))
3216 return -1;
3217
3218 p = &pg->records[i];
3219 p->flags = rec_flags;
3220
3221 /*
3222 * Do the initial record conversion from mcount jump
3223 * to the NOP instructions.
3224 */
3225 if (init_nop && !ftrace_nop_initialize(mod, p))
3226 break;
3227
3228 update_cnt++;
3229 }
3230 }
3231
3232 stop = ftrace_now(raw_smp_processor_id());
3233 ftrace_update_time = stop - start;
3234 ftrace_update_tot_cnt += update_cnt;
3235
3236 return 0;
3237}
3238
3239static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3240{
3241 int order;
3242 int pages;
3243 int cnt;
3244
3245 if (WARN_ON(!count))
3246 return -EINVAL;
3247
3248 /* We want to fill as much as possible, with no empty pages */
3249 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3250 order = fls(pages) - 1;
3251
3252 again:
3253 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3254
3255 if (!pg->records) {
3256 /* if we can't allocate this size, try something smaller */
3257 if (!order)
3258 return -ENOMEM;
3259 order--;
3260 goto again;
3261 }
3262
3263 ftrace_number_of_pages += 1 << order;
3264 ftrace_number_of_groups++;
3265
3266 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3267 pg->order = order;
3268
3269 if (cnt > count)
3270 cnt = count;
3271
3272 return cnt;
3273}
3274
3275static void ftrace_free_pages(struct ftrace_page *pages)
3276{
3277 struct ftrace_page *pg = pages;
3278
3279 while (pg) {
3280 if (pg->records) {
3281 free_pages((unsigned long)pg->records, pg->order);
3282 ftrace_number_of_pages -= 1 << pg->order;
3283 }
3284 pages = pg->next;
3285 kfree(pg);
3286 pg = pages;
3287 ftrace_number_of_groups--;
3288 }
3289}
3290
3291static struct ftrace_page *
3292ftrace_allocate_pages(unsigned long num_to_init)
3293{
3294 struct ftrace_page *start_pg;
3295 struct ftrace_page *pg;
3296 int cnt;
3297
3298 if (!num_to_init)
3299 return NULL;
3300
3301 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3302 if (!pg)
3303 return NULL;
3304
3305 /*
3306 * Try to allocate as much as possible in one continues
3307 * location that fills in all of the space. We want to
3308 * waste as little space as possible.
3309 */
3310 for (;;) {
3311 cnt = ftrace_allocate_records(pg, num_to_init);
3312 if (cnt < 0)
3313 goto free_pages;
3314
3315 num_to_init -= cnt;
3316 if (!num_to_init)
3317 break;
3318
3319 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3320 if (!pg->next)
3321 goto free_pages;
3322
3323 pg = pg->next;
3324 }
3325
3326 return start_pg;
3327
3328 free_pages:
3329 ftrace_free_pages(start_pg);
3330 pr_info("ftrace: FAILED to allocate memory for functions\n");
3331 return NULL;
3332}
3333
3334#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3335
3336struct ftrace_iterator {
3337 loff_t pos;
3338 loff_t func_pos;
3339 loff_t mod_pos;
3340 struct ftrace_page *pg;
3341 struct dyn_ftrace *func;
3342 struct ftrace_func_probe *probe;
3343 struct ftrace_func_entry *probe_entry;
3344 struct trace_parser parser;
3345 struct ftrace_hash *hash;
3346 struct ftrace_ops *ops;
3347 struct trace_array *tr;
3348 struct list_head *mod_list;
3349 int pidx;
3350 int idx;
3351 unsigned flags;
3352};
3353
3354static void *
3355t_probe_next(struct seq_file *m, loff_t *pos)
3356{
3357 struct ftrace_iterator *iter = m->private;
3358 struct trace_array *tr = iter->ops->private;
3359 struct list_head *func_probes;
3360 struct ftrace_hash *hash;
3361 struct list_head *next;
3362 struct hlist_node *hnd = NULL;
3363 struct hlist_head *hhd;
3364 int size;
3365
3366 (*pos)++;
3367 iter->pos = *pos;
3368
3369 if (!tr)
3370 return NULL;
3371
3372 func_probes = &tr->func_probes;
3373 if (list_empty(func_probes))
3374 return NULL;
3375
3376 if (!iter->probe) {
3377 next = func_probes->next;
3378 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3379 }
3380
3381 if (iter->probe_entry)
3382 hnd = &iter->probe_entry->hlist;
3383
3384 hash = iter->probe->ops.func_hash->filter_hash;
3385
3386 /*
3387 * A probe being registered may temporarily have an empty hash
3388 * and it's at the end of the func_probes list.
3389 */
3390 if (!hash || hash == EMPTY_HASH)
3391 return NULL;
3392
3393 size = 1 << hash->size_bits;
3394
3395 retry:
3396 if (iter->pidx >= size) {
3397 if (iter->probe->list.next == func_probes)
3398 return NULL;
3399 next = iter->probe->list.next;
3400 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3401 hash = iter->probe->ops.func_hash->filter_hash;
3402 size = 1 << hash->size_bits;
3403 iter->pidx = 0;
3404 }
3405
3406 hhd = &hash->buckets[iter->pidx];
3407
3408 if (hlist_empty(hhd)) {
3409 iter->pidx++;
3410 hnd = NULL;
3411 goto retry;
3412 }
3413
3414 if (!hnd)
3415 hnd = hhd->first;
3416 else {
3417 hnd = hnd->next;
3418 if (!hnd) {
3419 iter->pidx++;
3420 goto retry;
3421 }
3422 }
3423
3424 if (WARN_ON_ONCE(!hnd))
3425 return NULL;
3426
3427 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3428
3429 return iter;
3430}
3431
3432static void *t_probe_start(struct seq_file *m, loff_t *pos)
3433{
3434 struct ftrace_iterator *iter = m->private;
3435 void *p = NULL;
3436 loff_t l;
3437
3438 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3439 return NULL;
3440
3441 if (iter->mod_pos > *pos)
3442 return NULL;
3443
3444 iter->probe = NULL;
3445 iter->probe_entry = NULL;
3446 iter->pidx = 0;
3447 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3448 p = t_probe_next(m, &l);
3449 if (!p)
3450 break;
3451 }
3452 if (!p)
3453 return NULL;
3454
3455 /* Only set this if we have an item */
3456 iter->flags |= FTRACE_ITER_PROBE;
3457
3458 return iter;
3459}
3460
3461static int
3462t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3463{
3464 struct ftrace_func_entry *probe_entry;
3465 struct ftrace_probe_ops *probe_ops;
3466 struct ftrace_func_probe *probe;
3467
3468 probe = iter->probe;
3469 probe_entry = iter->probe_entry;
3470
3471 if (WARN_ON_ONCE(!probe || !probe_entry))
3472 return -EIO;
3473
3474 probe_ops = probe->probe_ops;
3475
3476 if (probe_ops->print)
3477 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3478
3479 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3480 (void *)probe_ops->func);
3481
3482 return 0;
3483}
3484
3485static void *
3486t_mod_next(struct seq_file *m, loff_t *pos)
3487{
3488 struct ftrace_iterator *iter = m->private;
3489 struct trace_array *tr = iter->tr;
3490
3491 (*pos)++;
3492 iter->pos = *pos;
3493
3494 iter->mod_list = iter->mod_list->next;
3495
3496 if (iter->mod_list == &tr->mod_trace ||
3497 iter->mod_list == &tr->mod_notrace) {
3498 iter->flags &= ~FTRACE_ITER_MOD;
3499 return NULL;
3500 }
3501
3502 iter->mod_pos = *pos;
3503
3504 return iter;
3505}
3506
3507static void *t_mod_start(struct seq_file *m, loff_t *pos)
3508{
3509 struct ftrace_iterator *iter = m->private;
3510 void *p = NULL;
3511 loff_t l;
3512
3513 if (iter->func_pos > *pos)
3514 return NULL;
3515
3516 iter->mod_pos = iter->func_pos;
3517
3518 /* probes are only available if tr is set */
3519 if (!iter->tr)
3520 return NULL;
3521
3522 for (l = 0; l <= (*pos - iter->func_pos); ) {
3523 p = t_mod_next(m, &l);
3524 if (!p)
3525 break;
3526 }
3527 if (!p) {
3528 iter->flags &= ~FTRACE_ITER_MOD;
3529 return t_probe_start(m, pos);
3530 }
3531
3532 /* Only set this if we have an item */
3533 iter->flags |= FTRACE_ITER_MOD;
3534
3535 return iter;
3536}
3537
3538static int
3539t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3540{
3541 struct ftrace_mod_load *ftrace_mod;
3542 struct trace_array *tr = iter->tr;
3543
3544 if (WARN_ON_ONCE(!iter->mod_list) ||
3545 iter->mod_list == &tr->mod_trace ||
3546 iter->mod_list == &tr->mod_notrace)
3547 return -EIO;
3548
3549 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3550
3551 if (ftrace_mod->func)
3552 seq_printf(m, "%s", ftrace_mod->func);
3553 else
3554 seq_putc(m, '*');
3555
3556 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3557
3558 return 0;
3559}
3560
3561static void *
3562t_func_next(struct seq_file *m, loff_t *pos)
3563{
3564 struct ftrace_iterator *iter = m->private;
3565 struct dyn_ftrace *rec = NULL;
3566
3567 (*pos)++;
3568
3569 retry:
3570 if (iter->idx >= iter->pg->index) {
3571 if (iter->pg->next) {
3572 iter->pg = iter->pg->next;
3573 iter->idx = 0;
3574 goto retry;
3575 }
3576 } else {
3577 rec = &iter->pg->records[iter->idx++];
3578 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3579 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3580
3581 ((iter->flags & FTRACE_ITER_ENABLED) &&
3582 !(rec->flags & FTRACE_FL_ENABLED)) ||
3583
3584 ((iter->flags & FTRACE_ITER_TOUCHED) &&
3585 !(rec->flags & FTRACE_FL_TOUCHED))) {
3586
3587 rec = NULL;
3588 goto retry;
3589 }
3590 }
3591
3592 if (!rec)
3593 return NULL;
3594
3595 iter->pos = iter->func_pos = *pos;
3596 iter->func = rec;
3597
3598 return iter;
3599}
3600
3601static void *
3602t_next(struct seq_file *m, void *v, loff_t *pos)
3603{
3604 struct ftrace_iterator *iter = m->private;
3605 loff_t l = *pos; /* t_probe_start() must use original pos */
3606 void *ret;
3607
3608 if (unlikely(ftrace_disabled))
3609 return NULL;
3610
3611 if (iter->flags & FTRACE_ITER_PROBE)
3612 return t_probe_next(m, pos);
3613
3614 if (iter->flags & FTRACE_ITER_MOD)
3615 return t_mod_next(m, pos);
3616
3617 if (iter->flags & FTRACE_ITER_PRINTALL) {
3618 /* next must increment pos, and t_probe_start does not */
3619 (*pos)++;
3620 return t_mod_start(m, &l);
3621 }
3622
3623 ret = t_func_next(m, pos);
3624
3625 if (!ret)
3626 return t_mod_start(m, &l);
3627
3628 return ret;
3629}
3630
3631static void reset_iter_read(struct ftrace_iterator *iter)
3632{
3633 iter->pos = 0;
3634 iter->func_pos = 0;
3635 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3636}
3637
3638static void *t_start(struct seq_file *m, loff_t *pos)
3639{
3640 struct ftrace_iterator *iter = m->private;
3641 void *p = NULL;
3642 loff_t l;
3643
3644 mutex_lock(&ftrace_lock);
3645
3646 if (unlikely(ftrace_disabled))
3647 return NULL;
3648
3649 /*
3650 * If an lseek was done, then reset and start from beginning.
3651 */
3652 if (*pos < iter->pos)
3653 reset_iter_read(iter);
3654
3655 /*
3656 * For set_ftrace_filter reading, if we have the filter
3657 * off, we can short cut and just print out that all
3658 * functions are enabled.
3659 */
3660 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3661 ftrace_hash_empty(iter->hash)) {
3662 iter->func_pos = 1; /* Account for the message */
3663 if (*pos > 0)
3664 return t_mod_start(m, pos);
3665 iter->flags |= FTRACE_ITER_PRINTALL;
3666 /* reset in case of seek/pread */
3667 iter->flags &= ~FTRACE_ITER_PROBE;
3668 return iter;
3669 }
3670
3671 if (iter->flags & FTRACE_ITER_MOD)
3672 return t_mod_start(m, pos);
3673
3674 /*
3675 * Unfortunately, we need to restart at ftrace_pages_start
3676 * every time we let go of the ftrace_mutex. This is because
3677 * those pointers can change without the lock.
3678 */
3679 iter->pg = ftrace_pages_start;
3680 iter->idx = 0;
3681 for (l = 0; l <= *pos; ) {
3682 p = t_func_next(m, &l);
3683 if (!p)
3684 break;
3685 }
3686
3687 if (!p)
3688 return t_mod_start(m, pos);
3689
3690 return iter;
3691}
3692
3693static void t_stop(struct seq_file *m, void *p)
3694{
3695 mutex_unlock(&ftrace_lock);
3696}
3697
3698void * __weak
3699arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3700{
3701 return NULL;
3702}
3703
3704static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3705 struct dyn_ftrace *rec)
3706{
3707 void *ptr;
3708
3709 ptr = arch_ftrace_trampoline_func(ops, rec);
3710 if (ptr)
3711 seq_printf(m, " ->%pS", ptr);
3712}
3713
3714#ifdef FTRACE_MCOUNT_MAX_OFFSET
3715/*
3716 * Weak functions can still have an mcount/fentry that is saved in
3717 * the __mcount_loc section. These can be detected by having a
3718 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3719 * symbol found by kallsyms is not the function that the mcount/fentry
3720 * is part of. The offset is much greater in these cases.
3721 *
3722 * Test the record to make sure that the ip points to a valid kallsyms
3723 * and if not, mark it disabled.
3724 */
3725static int test_for_valid_rec(struct dyn_ftrace *rec)
3726{
3727 char str[KSYM_SYMBOL_LEN];
3728 unsigned long offset;
3729 const char *ret;
3730
3731 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3732
3733 /* Weak functions can cause invalid addresses */
3734 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3735 rec->flags |= FTRACE_FL_DISABLED;
3736 return 0;
3737 }
3738 return 1;
3739}
3740
3741static struct workqueue_struct *ftrace_check_wq __initdata;
3742static struct work_struct ftrace_check_work __initdata;
3743
3744/*
3745 * Scan all the mcount/fentry entries to make sure they are valid.
3746 */
3747static __init void ftrace_check_work_func(struct work_struct *work)
3748{
3749 struct ftrace_page *pg;
3750 struct dyn_ftrace *rec;
3751
3752 mutex_lock(&ftrace_lock);
3753 do_for_each_ftrace_rec(pg, rec) {
3754 test_for_valid_rec(rec);
3755 } while_for_each_ftrace_rec();
3756 mutex_unlock(&ftrace_lock);
3757}
3758
3759static int __init ftrace_check_for_weak_functions(void)
3760{
3761 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3762
3763 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3764
3765 queue_work(ftrace_check_wq, &ftrace_check_work);
3766 return 0;
3767}
3768
3769static int __init ftrace_check_sync(void)
3770{
3771 /* Make sure the ftrace_check updates are finished */
3772 if (ftrace_check_wq)
3773 destroy_workqueue(ftrace_check_wq);
3774 return 0;
3775}
3776
3777late_initcall_sync(ftrace_check_sync);
3778subsys_initcall(ftrace_check_for_weak_functions);
3779
3780static int print_rec(struct seq_file *m, unsigned long ip)
3781{
3782 unsigned long offset;
3783 char str[KSYM_SYMBOL_LEN];
3784 char *modname;
3785 const char *ret;
3786
3787 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3788 /* Weak functions can cause invalid addresses */
3789 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3790 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3791 FTRACE_INVALID_FUNCTION, offset);
3792 ret = NULL;
3793 }
3794
3795 seq_puts(m, str);
3796 if (modname)
3797 seq_printf(m, " [%s]", modname);
3798 return ret == NULL ? -1 : 0;
3799}
3800#else
3801static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3802{
3803 return 1;
3804}
3805
3806static inline int print_rec(struct seq_file *m, unsigned long ip)
3807{
3808 seq_printf(m, "%ps", (void *)ip);
3809 return 0;
3810}
3811#endif
3812
3813static int t_show(struct seq_file *m, void *v)
3814{
3815 struct ftrace_iterator *iter = m->private;
3816 struct dyn_ftrace *rec;
3817
3818 if (iter->flags & FTRACE_ITER_PROBE)
3819 return t_probe_show(m, iter);
3820
3821 if (iter->flags & FTRACE_ITER_MOD)
3822 return t_mod_show(m, iter);
3823
3824 if (iter->flags & FTRACE_ITER_PRINTALL) {
3825 if (iter->flags & FTRACE_ITER_NOTRACE)
3826 seq_puts(m, "#### no functions disabled ####\n");
3827 else
3828 seq_puts(m, "#### all functions enabled ####\n");
3829 return 0;
3830 }
3831
3832 rec = iter->func;
3833
3834 if (!rec)
3835 return 0;
3836
3837 if (iter->flags & FTRACE_ITER_ADDRS)
3838 seq_printf(m, "%lx ", rec->ip);
3839
3840 if (print_rec(m, rec->ip)) {
3841 /* This should only happen when a rec is disabled */
3842 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3843 seq_putc(m, '\n');
3844 return 0;
3845 }
3846
3847 if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3848 struct ftrace_ops *ops;
3849
3850 seq_printf(m, " (%ld)%s%s%s%s%s",
3851 ftrace_rec_count(rec),
3852 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3853 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3854 rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
3855 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
3856 rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
3857 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3858 ops = ftrace_find_tramp_ops_any(rec);
3859 if (ops) {
3860 do {
3861 seq_printf(m, "\ttramp: %pS (%pS)",
3862 (void *)ops->trampoline,
3863 (void *)ops->func);
3864 add_trampoline_func(m, ops, rec);
3865 ops = ftrace_find_tramp_ops_next(rec, ops);
3866 } while (ops);
3867 } else
3868 seq_puts(m, "\ttramp: ERROR!");
3869 } else {
3870 add_trampoline_func(m, NULL, rec);
3871 }
3872 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3873 ops = ftrace_find_unique_ops(rec);
3874 if (ops) {
3875 seq_printf(m, "\tops: %pS (%pS)",
3876 ops, ops->func);
3877 } else {
3878 seq_puts(m, "\tops: ERROR!");
3879 }
3880 }
3881 if (rec->flags & FTRACE_FL_DIRECT) {
3882 unsigned long direct;
3883
3884 direct = ftrace_find_rec_direct(rec->ip);
3885 if (direct)
3886 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3887 }
3888 }
3889
3890 seq_putc(m, '\n');
3891
3892 return 0;
3893}
3894
3895static const struct seq_operations show_ftrace_seq_ops = {
3896 .start = t_start,
3897 .next = t_next,
3898 .stop = t_stop,
3899 .show = t_show,
3900};
3901
3902static int
3903ftrace_avail_open(struct inode *inode, struct file *file)
3904{
3905 struct ftrace_iterator *iter;
3906 int ret;
3907
3908 ret = security_locked_down(LOCKDOWN_TRACEFS);
3909 if (ret)
3910 return ret;
3911
3912 if (unlikely(ftrace_disabled))
3913 return -ENODEV;
3914
3915 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3916 if (!iter)
3917 return -ENOMEM;
3918
3919 iter->pg = ftrace_pages_start;
3920 iter->ops = &global_ops;
3921
3922 return 0;
3923}
3924
3925static int
3926ftrace_enabled_open(struct inode *inode, struct file *file)
3927{
3928 struct ftrace_iterator *iter;
3929
3930 /*
3931 * This shows us what functions are currently being
3932 * traced and by what. Not sure if we want lockdown
3933 * to hide such critical information for an admin.
3934 * Although, perhaps it can show information we don't
3935 * want people to see, but if something is tracing
3936 * something, we probably want to know about it.
3937 */
3938
3939 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3940 if (!iter)
3941 return -ENOMEM;
3942
3943 iter->pg = ftrace_pages_start;
3944 iter->flags = FTRACE_ITER_ENABLED;
3945 iter->ops = &global_ops;
3946
3947 return 0;
3948}
3949
3950static int
3951ftrace_touched_open(struct inode *inode, struct file *file)
3952{
3953 struct ftrace_iterator *iter;
3954
3955 /*
3956 * This shows us what functions have ever been enabled
3957 * (traced, direct, patched, etc). Not sure if we want lockdown
3958 * to hide such critical information for an admin.
3959 * Although, perhaps it can show information we don't
3960 * want people to see, but if something had traced
3961 * something, we probably want to know about it.
3962 */
3963
3964 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3965 if (!iter)
3966 return -ENOMEM;
3967
3968 iter->pg = ftrace_pages_start;
3969 iter->flags = FTRACE_ITER_TOUCHED;
3970 iter->ops = &global_ops;
3971
3972 return 0;
3973}
3974
3975static int
3976ftrace_avail_addrs_open(struct inode *inode, struct file *file)
3977{
3978 struct ftrace_iterator *iter;
3979 int ret;
3980
3981 ret = security_locked_down(LOCKDOWN_TRACEFS);
3982 if (ret)
3983 return ret;
3984
3985 if (unlikely(ftrace_disabled))
3986 return -ENODEV;
3987
3988 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3989 if (!iter)
3990 return -ENOMEM;
3991
3992 iter->pg = ftrace_pages_start;
3993 iter->flags = FTRACE_ITER_ADDRS;
3994 iter->ops = &global_ops;
3995
3996 return 0;
3997}
3998
3999/**
4000 * ftrace_regex_open - initialize function tracer filter files
4001 * @ops: The ftrace_ops that hold the hash filters
4002 * @flag: The type of filter to process
4003 * @inode: The inode, usually passed in to your open routine
4004 * @file: The file, usually passed in to your open routine
4005 *
4006 * ftrace_regex_open() initializes the filter files for the
4007 * @ops. Depending on @flag it may process the filter hash or
4008 * the notrace hash of @ops. With this called from the open
4009 * routine, you can use ftrace_filter_write() for the write
4010 * routine if @flag has FTRACE_ITER_FILTER set, or
4011 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4012 * tracing_lseek() should be used as the lseek routine, and
4013 * release must call ftrace_regex_release().
4014 *
4015 * Returns: 0 on success or a negative errno value on failure
4016 */
4017int
4018ftrace_regex_open(struct ftrace_ops *ops, int flag,
4019 struct inode *inode, struct file *file)
4020{
4021 struct ftrace_iterator *iter;
4022 struct ftrace_hash *hash;
4023 struct list_head *mod_head;
4024 struct trace_array *tr = ops->private;
4025 int ret = -ENOMEM;
4026
4027 ftrace_ops_init(ops);
4028
4029 if (unlikely(ftrace_disabled))
4030 return -ENODEV;
4031
4032 if (tracing_check_open_get_tr(tr))
4033 return -ENODEV;
4034
4035 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4036 if (!iter)
4037 goto out;
4038
4039 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4040 goto out;
4041
4042 iter->ops = ops;
4043 iter->flags = flag;
4044 iter->tr = tr;
4045
4046 mutex_lock(&ops->func_hash->regex_lock);
4047
4048 if (flag & FTRACE_ITER_NOTRACE) {
4049 hash = ops->func_hash->notrace_hash;
4050 mod_head = tr ? &tr->mod_notrace : NULL;
4051 } else {
4052 hash = ops->func_hash->filter_hash;
4053 mod_head = tr ? &tr->mod_trace : NULL;
4054 }
4055
4056 iter->mod_list = mod_head;
4057
4058 if (file->f_mode & FMODE_WRITE) {
4059 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4060
4061 if (file->f_flags & O_TRUNC) {
4062 iter->hash = alloc_ftrace_hash(size_bits);
4063 clear_ftrace_mod_list(mod_head);
4064 } else {
4065 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4066 }
4067
4068 if (!iter->hash) {
4069 trace_parser_put(&iter->parser);
4070 goto out_unlock;
4071 }
4072 } else
4073 iter->hash = hash;
4074
4075 ret = 0;
4076
4077 if (file->f_mode & FMODE_READ) {
4078 iter->pg = ftrace_pages_start;
4079
4080 ret = seq_open(file, &show_ftrace_seq_ops);
4081 if (!ret) {
4082 struct seq_file *m = file->private_data;
4083 m->private = iter;
4084 } else {
4085 /* Failed */
4086 free_ftrace_hash(iter->hash);
4087 trace_parser_put(&iter->parser);
4088 }
4089 } else
4090 file->private_data = iter;
4091
4092 out_unlock:
4093 mutex_unlock(&ops->func_hash->regex_lock);
4094
4095 out:
4096 if (ret) {
4097 kfree(iter);
4098 if (tr)
4099 trace_array_put(tr);
4100 }
4101
4102 return ret;
4103}
4104
4105static int
4106ftrace_filter_open(struct inode *inode, struct file *file)
4107{
4108 struct ftrace_ops *ops = inode->i_private;
4109
4110 /* Checks for tracefs lockdown */
4111 return ftrace_regex_open(ops,
4112 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4113 inode, file);
4114}
4115
4116static int
4117ftrace_notrace_open(struct inode *inode, struct file *file)
4118{
4119 struct ftrace_ops *ops = inode->i_private;
4120
4121 /* Checks for tracefs lockdown */
4122 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4123 inode, file);
4124}
4125
4126/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4127struct ftrace_glob {
4128 char *search;
4129 unsigned len;
4130 int type;
4131};
4132
4133/*
4134 * If symbols in an architecture don't correspond exactly to the user-visible
4135 * name of what they represent, it is possible to define this function to
4136 * perform the necessary adjustments.
4137*/
4138char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4139{
4140 return str;
4141}
4142
4143static int ftrace_match(char *str, struct ftrace_glob *g)
4144{
4145 int matched = 0;
4146 int slen;
4147
4148 str = arch_ftrace_match_adjust(str, g->search);
4149
4150 switch (g->type) {
4151 case MATCH_FULL:
4152 if (strcmp(str, g->search) == 0)
4153 matched = 1;
4154 break;
4155 case MATCH_FRONT_ONLY:
4156 if (strncmp(str, g->search, g->len) == 0)
4157 matched = 1;
4158 break;
4159 case MATCH_MIDDLE_ONLY:
4160 if (strstr(str, g->search))
4161 matched = 1;
4162 break;
4163 case MATCH_END_ONLY:
4164 slen = strlen(str);
4165 if (slen >= g->len &&
4166 memcmp(str + slen - g->len, g->search, g->len) == 0)
4167 matched = 1;
4168 break;
4169 case MATCH_GLOB:
4170 if (glob_match(g->search, str))
4171 matched = 1;
4172 break;
4173 }
4174
4175 return matched;
4176}
4177
4178static int
4179enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4180{
4181 struct ftrace_func_entry *entry;
4182 int ret = 0;
4183
4184 entry = ftrace_lookup_ip(hash, rec->ip);
4185 if (clear_filter) {
4186 /* Do nothing if it doesn't exist */
4187 if (!entry)
4188 return 0;
4189
4190 free_hash_entry(hash, entry);
4191 } else {
4192 /* Do nothing if it exists */
4193 if (entry)
4194 return 0;
4195 if (add_hash_entry(hash, rec->ip) == NULL)
4196 ret = -ENOMEM;
4197 }
4198 return ret;
4199}
4200
4201static int
4202add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4203 int clear_filter)
4204{
4205 long index = simple_strtoul(func_g->search, NULL, 0);
4206 struct ftrace_page *pg;
4207 struct dyn_ftrace *rec;
4208
4209 /* The index starts at 1 */
4210 if (--index < 0)
4211 return 0;
4212
4213 do_for_each_ftrace_rec(pg, rec) {
4214 if (pg->index <= index) {
4215 index -= pg->index;
4216 /* this is a double loop, break goes to the next page */
4217 break;
4218 }
4219 rec = &pg->records[index];
4220 enter_record(hash, rec, clear_filter);
4221 return 1;
4222 } while_for_each_ftrace_rec();
4223 return 0;
4224}
4225
4226#ifdef FTRACE_MCOUNT_MAX_OFFSET
4227static int lookup_ip(unsigned long ip, char **modname, char *str)
4228{
4229 unsigned long offset;
4230
4231 kallsyms_lookup(ip, NULL, &offset, modname, str);
4232 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4233 return -1;
4234 return 0;
4235}
4236#else
4237static int lookup_ip(unsigned long ip, char **modname, char *str)
4238{
4239 kallsyms_lookup(ip, NULL, NULL, modname, str);
4240 return 0;
4241}
4242#endif
4243
4244static int
4245ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4246 struct ftrace_glob *mod_g, int exclude_mod)
4247{
4248 char str[KSYM_SYMBOL_LEN];
4249 char *modname;
4250
4251 if (lookup_ip(rec->ip, &modname, str)) {
4252 /* This should only happen when a rec is disabled */
4253 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4254 !(rec->flags & FTRACE_FL_DISABLED));
4255 return 0;
4256 }
4257
4258 if (mod_g) {
4259 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4260
4261 /* blank module name to match all modules */
4262 if (!mod_g->len) {
4263 /* blank module globbing: modname xor exclude_mod */
4264 if (!exclude_mod != !modname)
4265 goto func_match;
4266 return 0;
4267 }
4268
4269 /*
4270 * exclude_mod is set to trace everything but the given
4271 * module. If it is set and the module matches, then
4272 * return 0. If it is not set, and the module doesn't match
4273 * also return 0. Otherwise, check the function to see if
4274 * that matches.
4275 */
4276 if (!mod_matches == !exclude_mod)
4277 return 0;
4278func_match:
4279 /* blank search means to match all funcs in the mod */
4280 if (!func_g->len)
4281 return 1;
4282 }
4283
4284 return ftrace_match(str, func_g);
4285}
4286
4287static int
4288match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4289{
4290 struct ftrace_page *pg;
4291 struct dyn_ftrace *rec;
4292 struct ftrace_glob func_g = { .type = MATCH_FULL };
4293 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4294 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4295 int exclude_mod = 0;
4296 int found = 0;
4297 int ret;
4298 int clear_filter = 0;
4299
4300 if (func) {
4301 func_g.type = filter_parse_regex(func, len, &func_g.search,
4302 &clear_filter);
4303 func_g.len = strlen(func_g.search);
4304 }
4305
4306 if (mod) {
4307 mod_g.type = filter_parse_regex(mod, strlen(mod),
4308 &mod_g.search, &exclude_mod);
4309 mod_g.len = strlen(mod_g.search);
4310 }
4311
4312 mutex_lock(&ftrace_lock);
4313
4314 if (unlikely(ftrace_disabled))
4315 goto out_unlock;
4316
4317 if (func_g.type == MATCH_INDEX) {
4318 found = add_rec_by_index(hash, &func_g, clear_filter);
4319 goto out_unlock;
4320 }
4321
4322 do_for_each_ftrace_rec(pg, rec) {
4323
4324 if (rec->flags & FTRACE_FL_DISABLED)
4325 continue;
4326
4327 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4328 ret = enter_record(hash, rec, clear_filter);
4329 if (ret < 0) {
4330 found = ret;
4331 goto out_unlock;
4332 }
4333 found = 1;
4334 }
4335 cond_resched();
4336 } while_for_each_ftrace_rec();
4337 out_unlock:
4338 mutex_unlock(&ftrace_lock);
4339
4340 return found;
4341}
4342
4343static int
4344ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4345{
4346 return match_records(hash, buff, len, NULL);
4347}
4348
4349static void ftrace_ops_update_code(struct ftrace_ops *ops,
4350 struct ftrace_ops_hash *old_hash)
4351{
4352 struct ftrace_ops *op;
4353
4354 if (!ftrace_enabled)
4355 return;
4356
4357 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4358 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4359 return;
4360 }
4361
4362 /*
4363 * If this is the shared global_ops filter, then we need to
4364 * check if there is another ops that shares it, is enabled.
4365 * If so, we still need to run the modify code.
4366 */
4367 if (ops->func_hash != &global_ops.local_hash)
4368 return;
4369
4370 do_for_each_ftrace_op(op, ftrace_ops_list) {
4371 if (op->func_hash == &global_ops.local_hash &&
4372 op->flags & FTRACE_OPS_FL_ENABLED) {
4373 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4374 /* Only need to do this once */
4375 return;
4376 }
4377 } while_for_each_ftrace_op(op);
4378}
4379
4380static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4381 struct ftrace_hash **orig_hash,
4382 struct ftrace_hash *hash,
4383 int enable)
4384{
4385 struct ftrace_ops_hash old_hash_ops;
4386 struct ftrace_hash *old_hash;
4387 int ret;
4388
4389 old_hash = *orig_hash;
4390 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4391 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4392 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4393 if (!ret) {
4394 ftrace_ops_update_code(ops, &old_hash_ops);
4395 free_ftrace_hash_rcu(old_hash);
4396 }
4397 return ret;
4398}
4399
4400static bool module_exists(const char *module)
4401{
4402 /* All modules have the symbol __this_module */
4403 static const char this_mod[] = "__this_module";
4404 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4405 unsigned long val;
4406 int n;
4407
4408 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4409
4410 if (n > sizeof(modname) - 1)
4411 return false;
4412
4413 val = module_kallsyms_lookup_name(modname);
4414 return val != 0;
4415}
4416
4417static int cache_mod(struct trace_array *tr,
4418 const char *func, char *module, int enable)
4419{
4420 struct ftrace_mod_load *ftrace_mod, *n;
4421 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4422 int ret;
4423
4424 mutex_lock(&ftrace_lock);
4425
4426 /* We do not cache inverse filters */
4427 if (func[0] == '!') {
4428 func++;
4429 ret = -EINVAL;
4430
4431 /* Look to remove this hash */
4432 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4433 if (strcmp(ftrace_mod->module, module) != 0)
4434 continue;
4435
4436 /* no func matches all */
4437 if (strcmp(func, "*") == 0 ||
4438 (ftrace_mod->func &&
4439 strcmp(ftrace_mod->func, func) == 0)) {
4440 ret = 0;
4441 free_ftrace_mod(ftrace_mod);
4442 continue;
4443 }
4444 }
4445 goto out;
4446 }
4447
4448 ret = -EINVAL;
4449 /* We only care about modules that have not been loaded yet */
4450 if (module_exists(module))
4451 goto out;
4452
4453 /* Save this string off, and execute it when the module is loaded */
4454 ret = ftrace_add_mod(tr, func, module, enable);
4455 out:
4456 mutex_unlock(&ftrace_lock);
4457
4458 return ret;
4459}
4460
4461static int
4462ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4463 int reset, int enable);
4464
4465#ifdef CONFIG_MODULES
4466static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4467 char *mod, bool enable)
4468{
4469 struct ftrace_mod_load *ftrace_mod, *n;
4470 struct ftrace_hash **orig_hash, *new_hash;
4471 LIST_HEAD(process_mods);
4472 char *func;
4473
4474 mutex_lock(&ops->func_hash->regex_lock);
4475
4476 if (enable)
4477 orig_hash = &ops->func_hash->filter_hash;
4478 else
4479 orig_hash = &ops->func_hash->notrace_hash;
4480
4481 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4482 *orig_hash);
4483 if (!new_hash)
4484 goto out; /* warn? */
4485
4486 mutex_lock(&ftrace_lock);
4487
4488 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4489
4490 if (strcmp(ftrace_mod->module, mod) != 0)
4491 continue;
4492
4493 if (ftrace_mod->func)
4494 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4495 else
4496 func = kstrdup("*", GFP_KERNEL);
4497
4498 if (!func) /* warn? */
4499 continue;
4500
4501 list_move(&ftrace_mod->list, &process_mods);
4502
4503 /* Use the newly allocated func, as it may be "*" */
4504 kfree(ftrace_mod->func);
4505 ftrace_mod->func = func;
4506 }
4507
4508 mutex_unlock(&ftrace_lock);
4509
4510 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4511
4512 func = ftrace_mod->func;
4513
4514 /* Grabs ftrace_lock, which is why we have this extra step */
4515 match_records(new_hash, func, strlen(func), mod);
4516 free_ftrace_mod(ftrace_mod);
4517 }
4518
4519 if (enable && list_empty(head))
4520 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4521
4522 mutex_lock(&ftrace_lock);
4523
4524 ftrace_hash_move_and_update_ops(ops, orig_hash,
4525 new_hash, enable);
4526 mutex_unlock(&ftrace_lock);
4527
4528 out:
4529 mutex_unlock(&ops->func_hash->regex_lock);
4530
4531 free_ftrace_hash(new_hash);
4532}
4533
4534static void process_cached_mods(const char *mod_name)
4535{
4536 struct trace_array *tr;
4537 char *mod;
4538
4539 mod = kstrdup(mod_name, GFP_KERNEL);
4540 if (!mod)
4541 return;
4542
4543 mutex_lock(&trace_types_lock);
4544 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4545 if (!list_empty(&tr->mod_trace))
4546 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4547 if (!list_empty(&tr->mod_notrace))
4548 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4549 }
4550 mutex_unlock(&trace_types_lock);
4551
4552 kfree(mod);
4553}
4554#endif
4555
4556/*
4557 * We register the module command as a template to show others how
4558 * to register the a command as well.
4559 */
4560
4561static int
4562ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4563 char *func_orig, char *cmd, char *module, int enable)
4564{
4565 char *func;
4566 int ret;
4567
4568 /* match_records() modifies func, and we need the original */
4569 func = kstrdup(func_orig, GFP_KERNEL);
4570 if (!func)
4571 return -ENOMEM;
4572
4573 /*
4574 * cmd == 'mod' because we only registered this func
4575 * for the 'mod' ftrace_func_command.
4576 * But if you register one func with multiple commands,
4577 * you can tell which command was used by the cmd
4578 * parameter.
4579 */
4580 ret = match_records(hash, func, strlen(func), module);
4581 kfree(func);
4582
4583 if (!ret)
4584 return cache_mod(tr, func_orig, module, enable);
4585 if (ret < 0)
4586 return ret;
4587 return 0;
4588}
4589
4590static struct ftrace_func_command ftrace_mod_cmd = {
4591 .name = "mod",
4592 .func = ftrace_mod_callback,
4593};
4594
4595static int __init ftrace_mod_cmd_init(void)
4596{
4597 return register_ftrace_command(&ftrace_mod_cmd);
4598}
4599core_initcall(ftrace_mod_cmd_init);
4600
4601static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4602 struct ftrace_ops *op, struct ftrace_regs *fregs)
4603{
4604 struct ftrace_probe_ops *probe_ops;
4605 struct ftrace_func_probe *probe;
4606
4607 probe = container_of(op, struct ftrace_func_probe, ops);
4608 probe_ops = probe->probe_ops;
4609
4610 /*
4611 * Disable preemption for these calls to prevent a RCU grace
4612 * period. This syncs the hash iteration and freeing of items
4613 * on the hash. rcu_read_lock is too dangerous here.
4614 */
4615 preempt_disable_notrace();
4616 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4617 preempt_enable_notrace();
4618}
4619
4620struct ftrace_func_map {
4621 struct ftrace_func_entry entry;
4622 void *data;
4623};
4624
4625struct ftrace_func_mapper {
4626 struct ftrace_hash hash;
4627};
4628
4629/**
4630 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4631 *
4632 * Returns: a ftrace_func_mapper descriptor that can be used to map ips to data.
4633 */
4634struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4635{
4636 struct ftrace_hash *hash;
4637
4638 /*
4639 * The mapper is simply a ftrace_hash, but since the entries
4640 * in the hash are not ftrace_func_entry type, we define it
4641 * as a separate structure.
4642 */
4643 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4644 return (struct ftrace_func_mapper *)hash;
4645}
4646
4647/**
4648 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4649 * @mapper: The mapper that has the ip maps
4650 * @ip: the instruction pointer to find the data for
4651 *
4652 * Returns: the data mapped to @ip if found otherwise NULL. The return
4653 * is actually the address of the mapper data pointer. The address is
4654 * returned for use cases where the data is no bigger than a long, and
4655 * the user can use the data pointer as its data instead of having to
4656 * allocate more memory for the reference.
4657 */
4658void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4659 unsigned long ip)
4660{
4661 struct ftrace_func_entry *entry;
4662 struct ftrace_func_map *map;
4663
4664 entry = ftrace_lookup_ip(&mapper->hash, ip);
4665 if (!entry)
4666 return NULL;
4667
4668 map = (struct ftrace_func_map *)entry;
4669 return &map->data;
4670}
4671
4672/**
4673 * ftrace_func_mapper_add_ip - Map some data to an ip
4674 * @mapper: The mapper that has the ip maps
4675 * @ip: The instruction pointer address to map @data to
4676 * @data: The data to map to @ip
4677 *
4678 * Returns: 0 on success otherwise an error.
4679 */
4680int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4681 unsigned long ip, void *data)
4682{
4683 struct ftrace_func_entry *entry;
4684 struct ftrace_func_map *map;
4685
4686 entry = ftrace_lookup_ip(&mapper->hash, ip);
4687 if (entry)
4688 return -EBUSY;
4689
4690 map = kmalloc(sizeof(*map), GFP_KERNEL);
4691 if (!map)
4692 return -ENOMEM;
4693
4694 map->entry.ip = ip;
4695 map->data = data;
4696
4697 __add_hash_entry(&mapper->hash, &map->entry);
4698
4699 return 0;
4700}
4701
4702/**
4703 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4704 * @mapper: The mapper that has the ip maps
4705 * @ip: The instruction pointer address to remove the data from
4706 *
4707 * Returns: the data if it is found, otherwise NULL.
4708 * Note, if the data pointer is used as the data itself, (see
4709 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4710 * if the data pointer was set to zero.
4711 */
4712void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4713 unsigned long ip)
4714{
4715 struct ftrace_func_entry *entry;
4716 struct ftrace_func_map *map;
4717 void *data;
4718
4719 entry = ftrace_lookup_ip(&mapper->hash, ip);
4720 if (!entry)
4721 return NULL;
4722
4723 map = (struct ftrace_func_map *)entry;
4724 data = map->data;
4725
4726 remove_hash_entry(&mapper->hash, entry);
4727 kfree(entry);
4728
4729 return data;
4730}
4731
4732/**
4733 * free_ftrace_func_mapper - free a mapping of ips and data
4734 * @mapper: The mapper that has the ip maps
4735 * @free_func: A function to be called on each data item.
4736 *
4737 * This is used to free the function mapper. The @free_func is optional
4738 * and can be used if the data needs to be freed as well.
4739 */
4740void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4741 ftrace_mapper_func free_func)
4742{
4743 struct ftrace_func_entry *entry;
4744 struct ftrace_func_map *map;
4745 struct hlist_head *hhd;
4746 int size, i;
4747
4748 if (!mapper)
4749 return;
4750
4751 if (free_func && mapper->hash.count) {
4752 size = 1 << mapper->hash.size_bits;
4753 for (i = 0; i < size; i++) {
4754 hhd = &mapper->hash.buckets[i];
4755 hlist_for_each_entry(entry, hhd, hlist) {
4756 map = (struct ftrace_func_map *)entry;
4757 free_func(map);
4758 }
4759 }
4760 }
4761 free_ftrace_hash(&mapper->hash);
4762}
4763
4764static void release_probe(struct ftrace_func_probe *probe)
4765{
4766 struct ftrace_probe_ops *probe_ops;
4767
4768 mutex_lock(&ftrace_lock);
4769
4770 WARN_ON(probe->ref <= 0);
4771
4772 /* Subtract the ref that was used to protect this instance */
4773 probe->ref--;
4774
4775 if (!probe->ref) {
4776 probe_ops = probe->probe_ops;
4777 /*
4778 * Sending zero as ip tells probe_ops to free
4779 * the probe->data itself
4780 */
4781 if (probe_ops->free)
4782 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4783 list_del(&probe->list);
4784 kfree(probe);
4785 }
4786 mutex_unlock(&ftrace_lock);
4787}
4788
4789static void acquire_probe_locked(struct ftrace_func_probe *probe)
4790{
4791 /*
4792 * Add one ref to keep it from being freed when releasing the
4793 * ftrace_lock mutex.
4794 */
4795 probe->ref++;
4796}
4797
4798int
4799register_ftrace_function_probe(char *glob, struct trace_array *tr,
4800 struct ftrace_probe_ops *probe_ops,
4801 void *data)
4802{
4803 struct ftrace_func_probe *probe = NULL, *iter;
4804 struct ftrace_func_entry *entry;
4805 struct ftrace_hash **orig_hash;
4806 struct ftrace_hash *old_hash;
4807 struct ftrace_hash *hash;
4808 int count = 0;
4809 int size;
4810 int ret;
4811 int i;
4812
4813 if (WARN_ON(!tr))
4814 return -EINVAL;
4815
4816 /* We do not support '!' for function probes */
4817 if (WARN_ON(glob[0] == '!'))
4818 return -EINVAL;
4819
4820
4821 mutex_lock(&ftrace_lock);
4822 /* Check if the probe_ops is already registered */
4823 list_for_each_entry(iter, &tr->func_probes, list) {
4824 if (iter->probe_ops == probe_ops) {
4825 probe = iter;
4826 break;
4827 }
4828 }
4829 if (!probe) {
4830 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4831 if (!probe) {
4832 mutex_unlock(&ftrace_lock);
4833 return -ENOMEM;
4834 }
4835 probe->probe_ops = probe_ops;
4836 probe->ops.func = function_trace_probe_call;
4837 probe->tr = tr;
4838 ftrace_ops_init(&probe->ops);
4839 list_add(&probe->list, &tr->func_probes);
4840 }
4841
4842 acquire_probe_locked(probe);
4843
4844 mutex_unlock(&ftrace_lock);
4845
4846 /*
4847 * Note, there's a small window here that the func_hash->filter_hash
4848 * may be NULL or empty. Need to be careful when reading the loop.
4849 */
4850 mutex_lock(&probe->ops.func_hash->regex_lock);
4851
4852 orig_hash = &probe->ops.func_hash->filter_hash;
4853 old_hash = *orig_hash;
4854 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4855
4856 if (!hash) {
4857 ret = -ENOMEM;
4858 goto out;
4859 }
4860
4861 ret = ftrace_match_records(hash, glob, strlen(glob));
4862
4863 /* Nothing found? */
4864 if (!ret)
4865 ret = -EINVAL;
4866
4867 if (ret < 0)
4868 goto out;
4869
4870 size = 1 << hash->size_bits;
4871 for (i = 0; i < size; i++) {
4872 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4873 if (ftrace_lookup_ip(old_hash, entry->ip))
4874 continue;
4875 /*
4876 * The caller might want to do something special
4877 * for each function we find. We call the callback
4878 * to give the caller an opportunity to do so.
4879 */
4880 if (probe_ops->init) {
4881 ret = probe_ops->init(probe_ops, tr,
4882 entry->ip, data,
4883 &probe->data);
4884 if (ret < 0) {
4885 if (probe_ops->free && count)
4886 probe_ops->free(probe_ops, tr,
4887 0, probe->data);
4888 probe->data = NULL;
4889 goto out;
4890 }
4891 }
4892 count++;
4893 }
4894 }
4895
4896 mutex_lock(&ftrace_lock);
4897
4898 if (!count) {
4899 /* Nothing was added? */
4900 ret = -EINVAL;
4901 goto out_unlock;
4902 }
4903
4904 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4905 hash, 1);
4906 if (ret < 0)
4907 goto err_unlock;
4908
4909 /* One ref for each new function traced */
4910 probe->ref += count;
4911
4912 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4913 ret = ftrace_startup(&probe->ops, 0);
4914
4915 out_unlock:
4916 mutex_unlock(&ftrace_lock);
4917
4918 if (!ret)
4919 ret = count;
4920 out:
4921 mutex_unlock(&probe->ops.func_hash->regex_lock);
4922 free_ftrace_hash(hash);
4923
4924 release_probe(probe);
4925
4926 return ret;
4927
4928 err_unlock:
4929 if (!probe_ops->free || !count)
4930 goto out_unlock;
4931
4932 /* Failed to do the move, need to call the free functions */
4933 for (i = 0; i < size; i++) {
4934 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4935 if (ftrace_lookup_ip(old_hash, entry->ip))
4936 continue;
4937 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4938 }
4939 }
4940 goto out_unlock;
4941}
4942
4943int
4944unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4945 struct ftrace_probe_ops *probe_ops)
4946{
4947 struct ftrace_func_probe *probe = NULL, *iter;
4948 struct ftrace_ops_hash old_hash_ops;
4949 struct ftrace_func_entry *entry;
4950 struct ftrace_glob func_g;
4951 struct ftrace_hash **orig_hash;
4952 struct ftrace_hash *old_hash;
4953 struct ftrace_hash *hash = NULL;
4954 struct hlist_node *tmp;
4955 struct hlist_head hhd;
4956 char str[KSYM_SYMBOL_LEN];
4957 int count = 0;
4958 int i, ret = -ENODEV;
4959 int size;
4960
4961 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4962 func_g.search = NULL;
4963 else {
4964 int not;
4965
4966 func_g.type = filter_parse_regex(glob, strlen(glob),
4967 &func_g.search, ¬);
4968 func_g.len = strlen(func_g.search);
4969
4970 /* we do not support '!' for function probes */
4971 if (WARN_ON(not))
4972 return -EINVAL;
4973 }
4974
4975 mutex_lock(&ftrace_lock);
4976 /* Check if the probe_ops is already registered */
4977 list_for_each_entry(iter, &tr->func_probes, list) {
4978 if (iter->probe_ops == probe_ops) {
4979 probe = iter;
4980 break;
4981 }
4982 }
4983 if (!probe)
4984 goto err_unlock_ftrace;
4985
4986 ret = -EINVAL;
4987 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4988 goto err_unlock_ftrace;
4989
4990 acquire_probe_locked(probe);
4991
4992 mutex_unlock(&ftrace_lock);
4993
4994 mutex_lock(&probe->ops.func_hash->regex_lock);
4995
4996 orig_hash = &probe->ops.func_hash->filter_hash;
4997 old_hash = *orig_hash;
4998
4999 if (ftrace_hash_empty(old_hash))
5000 goto out_unlock;
5001
5002 old_hash_ops.filter_hash = old_hash;
5003 /* Probes only have filters */
5004 old_hash_ops.notrace_hash = NULL;
5005
5006 ret = -ENOMEM;
5007 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5008 if (!hash)
5009 goto out_unlock;
5010
5011 INIT_HLIST_HEAD(&hhd);
5012
5013 size = 1 << hash->size_bits;
5014 for (i = 0; i < size; i++) {
5015 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5016
5017 if (func_g.search) {
5018 kallsyms_lookup(entry->ip, NULL, NULL,
5019 NULL, str);
5020 if (!ftrace_match(str, &func_g))
5021 continue;
5022 }
5023 count++;
5024 remove_hash_entry(hash, entry);
5025 hlist_add_head(&entry->hlist, &hhd);
5026 }
5027 }
5028
5029 /* Nothing found? */
5030 if (!count) {
5031 ret = -EINVAL;
5032 goto out_unlock;
5033 }
5034
5035 mutex_lock(&ftrace_lock);
5036
5037 WARN_ON(probe->ref < count);
5038
5039 probe->ref -= count;
5040
5041 if (ftrace_hash_empty(hash))
5042 ftrace_shutdown(&probe->ops, 0);
5043
5044 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5045 hash, 1);
5046
5047 /* still need to update the function call sites */
5048 if (ftrace_enabled && !ftrace_hash_empty(hash))
5049 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5050 &old_hash_ops);
5051 synchronize_rcu();
5052
5053 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5054 hlist_del(&entry->hlist);
5055 if (probe_ops->free)
5056 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5057 kfree(entry);
5058 }
5059 mutex_unlock(&ftrace_lock);
5060
5061 out_unlock:
5062 mutex_unlock(&probe->ops.func_hash->regex_lock);
5063 free_ftrace_hash(hash);
5064
5065 release_probe(probe);
5066
5067 return ret;
5068
5069 err_unlock_ftrace:
5070 mutex_unlock(&ftrace_lock);
5071 return ret;
5072}
5073
5074void clear_ftrace_function_probes(struct trace_array *tr)
5075{
5076 struct ftrace_func_probe *probe, *n;
5077
5078 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5079 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5080}
5081
5082static LIST_HEAD(ftrace_commands);
5083static DEFINE_MUTEX(ftrace_cmd_mutex);
5084
5085/*
5086 * Currently we only register ftrace commands from __init, so mark this
5087 * __init too.
5088 */
5089__init int register_ftrace_command(struct ftrace_func_command *cmd)
5090{
5091 struct ftrace_func_command *p;
5092 int ret = 0;
5093
5094 mutex_lock(&ftrace_cmd_mutex);
5095 list_for_each_entry(p, &ftrace_commands, list) {
5096 if (strcmp(cmd->name, p->name) == 0) {
5097 ret = -EBUSY;
5098 goto out_unlock;
5099 }
5100 }
5101 list_add(&cmd->list, &ftrace_commands);
5102 out_unlock:
5103 mutex_unlock(&ftrace_cmd_mutex);
5104
5105 return ret;
5106}
5107
5108/*
5109 * Currently we only unregister ftrace commands from __init, so mark
5110 * this __init too.
5111 */
5112__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5113{
5114 struct ftrace_func_command *p, *n;
5115 int ret = -ENODEV;
5116
5117 mutex_lock(&ftrace_cmd_mutex);
5118 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5119 if (strcmp(cmd->name, p->name) == 0) {
5120 ret = 0;
5121 list_del_init(&p->list);
5122 goto out_unlock;
5123 }
5124 }
5125 out_unlock:
5126 mutex_unlock(&ftrace_cmd_mutex);
5127
5128 return ret;
5129}
5130
5131static int ftrace_process_regex(struct ftrace_iterator *iter,
5132 char *buff, int len, int enable)
5133{
5134 struct ftrace_hash *hash = iter->hash;
5135 struct trace_array *tr = iter->ops->private;
5136 char *func, *command, *next = buff;
5137 struct ftrace_func_command *p;
5138 int ret = -EINVAL;
5139
5140 func = strsep(&next, ":");
5141
5142 if (!next) {
5143 ret = ftrace_match_records(hash, func, len);
5144 if (!ret)
5145 ret = -EINVAL;
5146 if (ret < 0)
5147 return ret;
5148 return 0;
5149 }
5150
5151 /* command found */
5152
5153 command = strsep(&next, ":");
5154
5155 mutex_lock(&ftrace_cmd_mutex);
5156 list_for_each_entry(p, &ftrace_commands, list) {
5157 if (strcmp(p->name, command) == 0) {
5158 ret = p->func(tr, hash, func, command, next, enable);
5159 goto out_unlock;
5160 }
5161 }
5162 out_unlock:
5163 mutex_unlock(&ftrace_cmd_mutex);
5164
5165 return ret;
5166}
5167
5168static ssize_t
5169ftrace_regex_write(struct file *file, const char __user *ubuf,
5170 size_t cnt, loff_t *ppos, int enable)
5171{
5172 struct ftrace_iterator *iter;
5173 struct trace_parser *parser;
5174 ssize_t ret, read;
5175
5176 if (!cnt)
5177 return 0;
5178
5179 if (file->f_mode & FMODE_READ) {
5180 struct seq_file *m = file->private_data;
5181 iter = m->private;
5182 } else
5183 iter = file->private_data;
5184
5185 if (unlikely(ftrace_disabled))
5186 return -ENODEV;
5187
5188 /* iter->hash is a local copy, so we don't need regex_lock */
5189
5190 parser = &iter->parser;
5191 read = trace_get_user(parser, ubuf, cnt, ppos);
5192
5193 if (read >= 0 && trace_parser_loaded(parser) &&
5194 !trace_parser_cont(parser)) {
5195 ret = ftrace_process_regex(iter, parser->buffer,
5196 parser->idx, enable);
5197 trace_parser_clear(parser);
5198 if (ret < 0)
5199 goto out;
5200 }
5201
5202 ret = read;
5203 out:
5204 return ret;
5205}
5206
5207ssize_t
5208ftrace_filter_write(struct file *file, const char __user *ubuf,
5209 size_t cnt, loff_t *ppos)
5210{
5211 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5212}
5213
5214ssize_t
5215ftrace_notrace_write(struct file *file, const char __user *ubuf,
5216 size_t cnt, loff_t *ppos)
5217{
5218 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5219}
5220
5221static int
5222__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5223{
5224 struct ftrace_func_entry *entry;
5225
5226 ip = ftrace_location(ip);
5227 if (!ip)
5228 return -EINVAL;
5229
5230 if (remove) {
5231 entry = ftrace_lookup_ip(hash, ip);
5232 if (!entry)
5233 return -ENOENT;
5234 free_hash_entry(hash, entry);
5235 return 0;
5236 }
5237
5238 entry = add_hash_entry(hash, ip);
5239 return entry ? 0 : -ENOMEM;
5240}
5241
5242static int
5243ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5244 unsigned int cnt, int remove)
5245{
5246 unsigned int i;
5247 int err;
5248
5249 for (i = 0; i < cnt; i++) {
5250 err = __ftrace_match_addr(hash, ips[i], remove);
5251 if (err) {
5252 /*
5253 * This expects the @hash is a temporary hash and if this
5254 * fails the caller must free the @hash.
5255 */
5256 return err;
5257 }
5258 }
5259 return 0;
5260}
5261
5262static int
5263ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5264 unsigned long *ips, unsigned int cnt,
5265 int remove, int reset, int enable)
5266{
5267 struct ftrace_hash **orig_hash;
5268 struct ftrace_hash *hash;
5269 int ret;
5270
5271 if (unlikely(ftrace_disabled))
5272 return -ENODEV;
5273
5274 mutex_lock(&ops->func_hash->regex_lock);
5275
5276 if (enable)
5277 orig_hash = &ops->func_hash->filter_hash;
5278 else
5279 orig_hash = &ops->func_hash->notrace_hash;
5280
5281 if (reset)
5282 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5283 else
5284 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5285
5286 if (!hash) {
5287 ret = -ENOMEM;
5288 goto out_regex_unlock;
5289 }
5290
5291 if (buf && !ftrace_match_records(hash, buf, len)) {
5292 ret = -EINVAL;
5293 goto out_regex_unlock;
5294 }
5295 if (ips) {
5296 ret = ftrace_match_addr(hash, ips, cnt, remove);
5297 if (ret < 0)
5298 goto out_regex_unlock;
5299 }
5300
5301 mutex_lock(&ftrace_lock);
5302 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5303 mutex_unlock(&ftrace_lock);
5304
5305 out_regex_unlock:
5306 mutex_unlock(&ops->func_hash->regex_lock);
5307
5308 free_ftrace_hash(hash);
5309 return ret;
5310}
5311
5312static int
5313ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5314 int remove, int reset, int enable)
5315{
5316 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5317}
5318
5319#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5320
5321struct ftrace_direct_func {
5322 struct list_head next;
5323 unsigned long addr;
5324 int count;
5325};
5326
5327static LIST_HEAD(ftrace_direct_funcs);
5328
5329static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5330
5331/*
5332 * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
5333 * call will be jumped from ftrace_regs_caller. Only if the architecture does
5334 * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
5335 * jumps from ftrace_caller for multiple ftrace_ops.
5336 */
5337#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
5338#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5339#else
5340#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5341#endif
5342
5343static int check_direct_multi(struct ftrace_ops *ops)
5344{
5345 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5346 return -EINVAL;
5347 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5348 return -EINVAL;
5349 return 0;
5350}
5351
5352static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5353{
5354 struct ftrace_func_entry *entry, *del;
5355 int size, i;
5356
5357 size = 1 << hash->size_bits;
5358 for (i = 0; i < size; i++) {
5359 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5360 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5361 if (del && del->direct == addr) {
5362 remove_hash_entry(direct_functions, del);
5363 kfree(del);
5364 }
5365 }
5366 }
5367}
5368
5369/**
5370 * register_ftrace_direct - Call a custom trampoline directly
5371 * for multiple functions registered in @ops
5372 * @ops: The address of the struct ftrace_ops object
5373 * @addr: The address of the trampoline to call at @ops functions
5374 *
5375 * This is used to connect a direct calls to @addr from the nop locations
5376 * of the functions registered in @ops (with by ftrace_set_filter_ip
5377 * function).
5378 *
5379 * The location that it calls (@addr) must be able to handle a direct call,
5380 * and save the parameters of the function being traced, and restore them
5381 * (or inject new ones if needed), before returning.
5382 *
5383 * Returns:
5384 * 0 on success
5385 * -EINVAL - The @ops object was already registered with this call or
5386 * when there are no functions in @ops object.
5387 * -EBUSY - Another direct function is already attached (there can be only one)
5388 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5389 * -ENOMEM - There was an allocation failure.
5390 */
5391int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5392{
5393 struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL;
5394 struct ftrace_func_entry *entry, *new;
5395 int err = -EBUSY, size, i;
5396
5397 if (ops->func || ops->trampoline)
5398 return -EINVAL;
5399 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5400 return -EINVAL;
5401 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5402 return -EINVAL;
5403
5404 hash = ops->func_hash->filter_hash;
5405 if (ftrace_hash_empty(hash))
5406 return -EINVAL;
5407
5408 mutex_lock(&direct_mutex);
5409
5410 /* Make sure requested entries are not already registered.. */
5411 size = 1 << hash->size_bits;
5412 for (i = 0; i < size; i++) {
5413 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5414 if (ftrace_find_rec_direct(entry->ip))
5415 goto out_unlock;
5416 }
5417 }
5418
5419 err = -ENOMEM;
5420
5421 /* Make a copy hash to place the new and the old entries in */
5422 size = hash->count + direct_functions->count;
5423 if (size > 32)
5424 size = 32;
5425 new_hash = alloc_ftrace_hash(fls(size));
5426 if (!new_hash)
5427 goto out_unlock;
5428
5429 /* Now copy over the existing direct entries */
5430 size = 1 << direct_functions->size_bits;
5431 for (i = 0; i < size; i++) {
5432 hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) {
5433 new = add_hash_entry(new_hash, entry->ip);
5434 if (!new)
5435 goto out_unlock;
5436 new->direct = entry->direct;
5437 }
5438 }
5439
5440 /* ... and add the new entries */
5441 size = 1 << hash->size_bits;
5442 for (i = 0; i < size; i++) {
5443 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5444 new = add_hash_entry(new_hash, entry->ip);
5445 if (!new)
5446 goto out_unlock;
5447 /* Update both the copy and the hash entry */
5448 new->direct = addr;
5449 entry->direct = addr;
5450 }
5451 }
5452
5453 free_hash = direct_functions;
5454 rcu_assign_pointer(direct_functions, new_hash);
5455 new_hash = NULL;
5456
5457 ops->func = call_direct_funcs;
5458 ops->flags = MULTI_FLAGS;
5459 ops->trampoline = FTRACE_REGS_ADDR;
5460 ops->direct_call = addr;
5461
5462 err = register_ftrace_function_nolock(ops);
5463
5464 out_unlock:
5465 mutex_unlock(&direct_mutex);
5466
5467 if (free_hash && free_hash != EMPTY_HASH) {
5468 synchronize_rcu_tasks();
5469 free_ftrace_hash(free_hash);
5470 }
5471
5472 if (new_hash)
5473 free_ftrace_hash(new_hash);
5474
5475 return err;
5476}
5477EXPORT_SYMBOL_GPL(register_ftrace_direct);
5478
5479/**
5480 * unregister_ftrace_direct - Remove calls to custom trampoline
5481 * previously registered by register_ftrace_direct for @ops object.
5482 * @ops: The address of the struct ftrace_ops object
5483 *
5484 * This is used to remove a direct calls to @addr from the nop locations
5485 * of the functions registered in @ops (with by ftrace_set_filter_ip
5486 * function).
5487 *
5488 * Returns:
5489 * 0 on success
5490 * -EINVAL - The @ops object was not properly registered.
5491 */
5492int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5493 bool free_filters)
5494{
5495 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5496 int err;
5497
5498 if (check_direct_multi(ops))
5499 return -EINVAL;
5500 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5501 return -EINVAL;
5502
5503 mutex_lock(&direct_mutex);
5504 err = unregister_ftrace_function(ops);
5505 remove_direct_functions_hash(hash, addr);
5506 mutex_unlock(&direct_mutex);
5507
5508 /* cleanup for possible another register call */
5509 ops->func = NULL;
5510 ops->trampoline = 0;
5511
5512 if (free_filters)
5513 ftrace_free_filter(ops);
5514 return err;
5515}
5516EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5517
5518static int
5519__modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5520{
5521 struct ftrace_hash *hash;
5522 struct ftrace_func_entry *entry, *iter;
5523 static struct ftrace_ops tmp_ops = {
5524 .func = ftrace_stub,
5525 .flags = FTRACE_OPS_FL_STUB,
5526 };
5527 int i, size;
5528 int err;
5529
5530 lockdep_assert_held_once(&direct_mutex);
5531
5532 /* Enable the tmp_ops to have the same functions as the direct ops */
5533 ftrace_ops_init(&tmp_ops);
5534 tmp_ops.func_hash = ops->func_hash;
5535 tmp_ops.direct_call = addr;
5536
5537 err = register_ftrace_function_nolock(&tmp_ops);
5538 if (err)
5539 return err;
5540
5541 /*
5542 * Now the ftrace_ops_list_func() is called to do the direct callers.
5543 * We can safely change the direct functions attached to each entry.
5544 */
5545 mutex_lock(&ftrace_lock);
5546
5547 hash = ops->func_hash->filter_hash;
5548 size = 1 << hash->size_bits;
5549 for (i = 0; i < size; i++) {
5550 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5551 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5552 if (!entry)
5553 continue;
5554 entry->direct = addr;
5555 }
5556 }
5557 /* Prevent store tearing if a trampoline concurrently accesses the value */
5558 WRITE_ONCE(ops->direct_call, addr);
5559
5560 mutex_unlock(&ftrace_lock);
5561
5562 /* Removing the tmp_ops will add the updated direct callers to the functions */
5563 unregister_ftrace_function(&tmp_ops);
5564
5565 return err;
5566}
5567
5568/**
5569 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5570 * to call something else
5571 * @ops: The address of the struct ftrace_ops object
5572 * @addr: The address of the new trampoline to call at @ops functions
5573 *
5574 * This is used to unregister currently registered direct caller and
5575 * register new one @addr on functions registered in @ops object.
5576 *
5577 * Note there's window between ftrace_shutdown and ftrace_startup calls
5578 * where there will be no callbacks called.
5579 *
5580 * Caller should already have direct_mutex locked, so we don't lock
5581 * direct_mutex here.
5582 *
5583 * Returns: zero on success. Non zero on error, which includes:
5584 * -EINVAL - The @ops object was not properly registered.
5585 */
5586int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5587{
5588 if (check_direct_multi(ops))
5589 return -EINVAL;
5590 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5591 return -EINVAL;
5592
5593 return __modify_ftrace_direct(ops, addr);
5594}
5595EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5596
5597/**
5598 * modify_ftrace_direct - Modify an existing direct 'multi' call
5599 * to call something else
5600 * @ops: The address of the struct ftrace_ops object
5601 * @addr: The address of the new trampoline to call at @ops functions
5602 *
5603 * This is used to unregister currently registered direct caller and
5604 * register new one @addr on functions registered in @ops object.
5605 *
5606 * Note there's window between ftrace_shutdown and ftrace_startup calls
5607 * where there will be no callbacks called.
5608 *
5609 * Returns: zero on success. Non zero on error, which includes:
5610 * -EINVAL - The @ops object was not properly registered.
5611 */
5612int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5613{
5614 int err;
5615
5616 if (check_direct_multi(ops))
5617 return -EINVAL;
5618 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5619 return -EINVAL;
5620
5621 mutex_lock(&direct_mutex);
5622 err = __modify_ftrace_direct(ops, addr);
5623 mutex_unlock(&direct_mutex);
5624 return err;
5625}
5626EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5627#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5628
5629/**
5630 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5631 * @ops: the ops to set the filter with
5632 * @ip: the address to add to or remove from the filter.
5633 * @remove: non zero to remove the ip from the filter
5634 * @reset: non zero to reset all filters before applying this filter.
5635 *
5636 * Filters denote which functions should be enabled when tracing is enabled
5637 * If @ip is NULL, it fails to update filter.
5638 *
5639 * This can allocate memory which must be freed before @ops can be freed,
5640 * either by removing each filtered addr or by using
5641 * ftrace_free_filter(@ops).
5642 */
5643int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5644 int remove, int reset)
5645{
5646 ftrace_ops_init(ops);
5647 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5648}
5649EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5650
5651/**
5652 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5653 * @ops: the ops to set the filter with
5654 * @ips: the array of addresses to add to or remove from the filter.
5655 * @cnt: the number of addresses in @ips
5656 * @remove: non zero to remove ips from the filter
5657 * @reset: non zero to reset all filters before applying this filter.
5658 *
5659 * Filters denote which functions should be enabled when tracing is enabled
5660 * If @ips array or any ip specified within is NULL , it fails to update filter.
5661 *
5662 * This can allocate memory which must be freed before @ops can be freed,
5663 * either by removing each filtered addr or by using
5664 * ftrace_free_filter(@ops).
5665*/
5666int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5667 unsigned int cnt, int remove, int reset)
5668{
5669 ftrace_ops_init(ops);
5670 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5671}
5672EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5673
5674/**
5675 * ftrace_ops_set_global_filter - setup ops to use global filters
5676 * @ops: the ops which will use the global filters
5677 *
5678 * ftrace users who need global function trace filtering should call this.
5679 * It can set the global filter only if ops were not initialized before.
5680 */
5681void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5682{
5683 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5684 return;
5685
5686 ftrace_ops_init(ops);
5687 ops->func_hash = &global_ops.local_hash;
5688}
5689EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5690
5691static int
5692ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5693 int reset, int enable)
5694{
5695 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5696}
5697
5698/**
5699 * ftrace_set_filter - set a function to filter on in ftrace
5700 * @ops: the ops to set the filter with
5701 * @buf: the string that holds the function filter text.
5702 * @len: the length of the string.
5703 * @reset: non-zero to reset all filters before applying this filter.
5704 *
5705 * Filters denote which functions should be enabled when tracing is enabled.
5706 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5707 *
5708 * This can allocate memory which must be freed before @ops can be freed,
5709 * either by removing each filtered addr or by using
5710 * ftrace_free_filter(@ops).
5711 */
5712int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5713 int len, int reset)
5714{
5715 ftrace_ops_init(ops);
5716 return ftrace_set_regex(ops, buf, len, reset, 1);
5717}
5718EXPORT_SYMBOL_GPL(ftrace_set_filter);
5719
5720/**
5721 * ftrace_set_notrace - set a function to not trace in ftrace
5722 * @ops: the ops to set the notrace filter with
5723 * @buf: the string that holds the function notrace text.
5724 * @len: the length of the string.
5725 * @reset: non-zero to reset all filters before applying this filter.
5726 *
5727 * Notrace Filters denote which functions should not be enabled when tracing
5728 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5729 * for tracing.
5730 *
5731 * This can allocate memory which must be freed before @ops can be freed,
5732 * either by removing each filtered addr or by using
5733 * ftrace_free_filter(@ops).
5734 */
5735int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5736 int len, int reset)
5737{
5738 ftrace_ops_init(ops);
5739 return ftrace_set_regex(ops, buf, len, reset, 0);
5740}
5741EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5742/**
5743 * ftrace_set_global_filter - set a function to filter on with global tracers
5744 * @buf: the string that holds the function filter text.
5745 * @len: the length of the string.
5746 * @reset: non-zero to reset all filters before applying this filter.
5747 *
5748 * Filters denote which functions should be enabled when tracing is enabled.
5749 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5750 */
5751void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5752{
5753 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5754}
5755EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5756
5757/**
5758 * ftrace_set_global_notrace - set a function to not trace with global tracers
5759 * @buf: the string that holds the function notrace text.
5760 * @len: the length of the string.
5761 * @reset: non-zero to reset all filters before applying this filter.
5762 *
5763 * Notrace Filters denote which functions should not be enabled when tracing
5764 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5765 * for tracing.
5766 */
5767void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5768{
5769 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5770}
5771EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5772
5773/*
5774 * command line interface to allow users to set filters on boot up.
5775 */
5776#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5777static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5778static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5779
5780/* Used by function selftest to not test if filter is set */
5781bool ftrace_filter_param __initdata;
5782
5783static int __init set_ftrace_notrace(char *str)
5784{
5785 ftrace_filter_param = true;
5786 strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5787 return 1;
5788}
5789__setup("ftrace_notrace=", set_ftrace_notrace);
5790
5791static int __init set_ftrace_filter(char *str)
5792{
5793 ftrace_filter_param = true;
5794 strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5795 return 1;
5796}
5797__setup("ftrace_filter=", set_ftrace_filter);
5798
5799#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5800static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5801static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5802static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5803
5804static int __init set_graph_function(char *str)
5805{
5806 strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5807 return 1;
5808}
5809__setup("ftrace_graph_filter=", set_graph_function);
5810
5811static int __init set_graph_notrace_function(char *str)
5812{
5813 strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5814 return 1;
5815}
5816__setup("ftrace_graph_notrace=", set_graph_notrace_function);
5817
5818static int __init set_graph_max_depth_function(char *str)
5819{
5820 if (!str)
5821 return 0;
5822 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5823 return 1;
5824}
5825__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5826
5827static void __init set_ftrace_early_graph(char *buf, int enable)
5828{
5829 int ret;
5830 char *func;
5831 struct ftrace_hash *hash;
5832
5833 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5834 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5835 return;
5836
5837 while (buf) {
5838 func = strsep(&buf, ",");
5839 /* we allow only one expression at a time */
5840 ret = ftrace_graph_set_hash(hash, func);
5841 if (ret)
5842 printk(KERN_DEBUG "ftrace: function %s not "
5843 "traceable\n", func);
5844 }
5845
5846 if (enable)
5847 ftrace_graph_hash = hash;
5848 else
5849 ftrace_graph_notrace_hash = hash;
5850}
5851#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5852
5853void __init
5854ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5855{
5856 char *func;
5857
5858 ftrace_ops_init(ops);
5859
5860 while (buf) {
5861 func = strsep(&buf, ",");
5862 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5863 }
5864}
5865
5866static void __init set_ftrace_early_filters(void)
5867{
5868 if (ftrace_filter_buf[0])
5869 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5870 if (ftrace_notrace_buf[0])
5871 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5872#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5873 if (ftrace_graph_buf[0])
5874 set_ftrace_early_graph(ftrace_graph_buf, 1);
5875 if (ftrace_graph_notrace_buf[0])
5876 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5877#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5878}
5879
5880int ftrace_regex_release(struct inode *inode, struct file *file)
5881{
5882 struct seq_file *m = (struct seq_file *)file->private_data;
5883 struct ftrace_iterator *iter;
5884 struct ftrace_hash **orig_hash;
5885 struct trace_parser *parser;
5886 int filter_hash;
5887
5888 if (file->f_mode & FMODE_READ) {
5889 iter = m->private;
5890 seq_release(inode, file);
5891 } else
5892 iter = file->private_data;
5893
5894 parser = &iter->parser;
5895 if (trace_parser_loaded(parser)) {
5896 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5897
5898 ftrace_process_regex(iter, parser->buffer,
5899 parser->idx, enable);
5900 }
5901
5902 trace_parser_put(parser);
5903
5904 mutex_lock(&iter->ops->func_hash->regex_lock);
5905
5906 if (file->f_mode & FMODE_WRITE) {
5907 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5908
5909 if (filter_hash) {
5910 orig_hash = &iter->ops->func_hash->filter_hash;
5911 if (iter->tr) {
5912 if (list_empty(&iter->tr->mod_trace))
5913 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5914 else
5915 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5916 }
5917 } else
5918 orig_hash = &iter->ops->func_hash->notrace_hash;
5919
5920 mutex_lock(&ftrace_lock);
5921 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5922 iter->hash, filter_hash);
5923 mutex_unlock(&ftrace_lock);
5924 } else {
5925 /* For read only, the hash is the ops hash */
5926 iter->hash = NULL;
5927 }
5928
5929 mutex_unlock(&iter->ops->func_hash->regex_lock);
5930 free_ftrace_hash(iter->hash);
5931 if (iter->tr)
5932 trace_array_put(iter->tr);
5933 kfree(iter);
5934
5935 return 0;
5936}
5937
5938static const struct file_operations ftrace_avail_fops = {
5939 .open = ftrace_avail_open,
5940 .read = seq_read,
5941 .llseek = seq_lseek,
5942 .release = seq_release_private,
5943};
5944
5945static const struct file_operations ftrace_enabled_fops = {
5946 .open = ftrace_enabled_open,
5947 .read = seq_read,
5948 .llseek = seq_lseek,
5949 .release = seq_release_private,
5950};
5951
5952static const struct file_operations ftrace_touched_fops = {
5953 .open = ftrace_touched_open,
5954 .read = seq_read,
5955 .llseek = seq_lseek,
5956 .release = seq_release_private,
5957};
5958
5959static const struct file_operations ftrace_avail_addrs_fops = {
5960 .open = ftrace_avail_addrs_open,
5961 .read = seq_read,
5962 .llseek = seq_lseek,
5963 .release = seq_release_private,
5964};
5965
5966static const struct file_operations ftrace_filter_fops = {
5967 .open = ftrace_filter_open,
5968 .read = seq_read,
5969 .write = ftrace_filter_write,
5970 .llseek = tracing_lseek,
5971 .release = ftrace_regex_release,
5972};
5973
5974static const struct file_operations ftrace_notrace_fops = {
5975 .open = ftrace_notrace_open,
5976 .read = seq_read,
5977 .write = ftrace_notrace_write,
5978 .llseek = tracing_lseek,
5979 .release = ftrace_regex_release,
5980};
5981
5982#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5983
5984static DEFINE_MUTEX(graph_lock);
5985
5986struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5987struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5988
5989enum graph_filter_type {
5990 GRAPH_FILTER_NOTRACE = 0,
5991 GRAPH_FILTER_FUNCTION,
5992};
5993
5994#define FTRACE_GRAPH_EMPTY ((void *)1)
5995
5996struct ftrace_graph_data {
5997 struct ftrace_hash *hash;
5998 struct ftrace_func_entry *entry;
5999 int idx; /* for hash table iteration */
6000 enum graph_filter_type type;
6001 struct ftrace_hash *new_hash;
6002 const struct seq_operations *seq_ops;
6003 struct trace_parser parser;
6004};
6005
6006static void *
6007__g_next(struct seq_file *m, loff_t *pos)
6008{
6009 struct ftrace_graph_data *fgd = m->private;
6010 struct ftrace_func_entry *entry = fgd->entry;
6011 struct hlist_head *head;
6012 int i, idx = fgd->idx;
6013
6014 if (*pos >= fgd->hash->count)
6015 return NULL;
6016
6017 if (entry) {
6018 hlist_for_each_entry_continue(entry, hlist) {
6019 fgd->entry = entry;
6020 return entry;
6021 }
6022
6023 idx++;
6024 }
6025
6026 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6027 head = &fgd->hash->buckets[i];
6028 hlist_for_each_entry(entry, head, hlist) {
6029 fgd->entry = entry;
6030 fgd->idx = i;
6031 return entry;
6032 }
6033 }
6034 return NULL;
6035}
6036
6037static void *
6038g_next(struct seq_file *m, void *v, loff_t *pos)
6039{
6040 (*pos)++;
6041 return __g_next(m, pos);
6042}
6043
6044static void *g_start(struct seq_file *m, loff_t *pos)
6045{
6046 struct ftrace_graph_data *fgd = m->private;
6047
6048 mutex_lock(&graph_lock);
6049
6050 if (fgd->type == GRAPH_FILTER_FUNCTION)
6051 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6052 lockdep_is_held(&graph_lock));
6053 else
6054 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6055 lockdep_is_held(&graph_lock));
6056
6057 /* Nothing, tell g_show to print all functions are enabled */
6058 if (ftrace_hash_empty(fgd->hash) && !*pos)
6059 return FTRACE_GRAPH_EMPTY;
6060
6061 fgd->idx = 0;
6062 fgd->entry = NULL;
6063 return __g_next(m, pos);
6064}
6065
6066static void g_stop(struct seq_file *m, void *p)
6067{
6068 mutex_unlock(&graph_lock);
6069}
6070
6071static int g_show(struct seq_file *m, void *v)
6072{
6073 struct ftrace_func_entry *entry = v;
6074
6075 if (!entry)
6076 return 0;
6077
6078 if (entry == FTRACE_GRAPH_EMPTY) {
6079 struct ftrace_graph_data *fgd = m->private;
6080
6081 if (fgd->type == GRAPH_FILTER_FUNCTION)
6082 seq_puts(m, "#### all functions enabled ####\n");
6083 else
6084 seq_puts(m, "#### no functions disabled ####\n");
6085 return 0;
6086 }
6087
6088 seq_printf(m, "%ps\n", (void *)entry->ip);
6089
6090 return 0;
6091}
6092
6093static const struct seq_operations ftrace_graph_seq_ops = {
6094 .start = g_start,
6095 .next = g_next,
6096 .stop = g_stop,
6097 .show = g_show,
6098};
6099
6100static int
6101__ftrace_graph_open(struct inode *inode, struct file *file,
6102 struct ftrace_graph_data *fgd)
6103{
6104 int ret;
6105 struct ftrace_hash *new_hash = NULL;
6106
6107 ret = security_locked_down(LOCKDOWN_TRACEFS);
6108 if (ret)
6109 return ret;
6110
6111 if (file->f_mode & FMODE_WRITE) {
6112 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6113
6114 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6115 return -ENOMEM;
6116
6117 if (file->f_flags & O_TRUNC)
6118 new_hash = alloc_ftrace_hash(size_bits);
6119 else
6120 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6121 fgd->hash);
6122 if (!new_hash) {
6123 ret = -ENOMEM;
6124 goto out;
6125 }
6126 }
6127
6128 if (file->f_mode & FMODE_READ) {
6129 ret = seq_open(file, &ftrace_graph_seq_ops);
6130 if (!ret) {
6131 struct seq_file *m = file->private_data;
6132 m->private = fgd;
6133 } else {
6134 /* Failed */
6135 free_ftrace_hash(new_hash);
6136 new_hash = NULL;
6137 }
6138 } else
6139 file->private_data = fgd;
6140
6141out:
6142 if (ret < 0 && file->f_mode & FMODE_WRITE)
6143 trace_parser_put(&fgd->parser);
6144
6145 fgd->new_hash = new_hash;
6146
6147 /*
6148 * All uses of fgd->hash must be taken with the graph_lock
6149 * held. The graph_lock is going to be released, so force
6150 * fgd->hash to be reinitialized when it is taken again.
6151 */
6152 fgd->hash = NULL;
6153
6154 return ret;
6155}
6156
6157static int
6158ftrace_graph_open(struct inode *inode, struct file *file)
6159{
6160 struct ftrace_graph_data *fgd;
6161 int ret;
6162
6163 if (unlikely(ftrace_disabled))
6164 return -ENODEV;
6165
6166 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6167 if (fgd == NULL)
6168 return -ENOMEM;
6169
6170 mutex_lock(&graph_lock);
6171
6172 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6173 lockdep_is_held(&graph_lock));
6174 fgd->type = GRAPH_FILTER_FUNCTION;
6175 fgd->seq_ops = &ftrace_graph_seq_ops;
6176
6177 ret = __ftrace_graph_open(inode, file, fgd);
6178 if (ret < 0)
6179 kfree(fgd);
6180
6181 mutex_unlock(&graph_lock);
6182 return ret;
6183}
6184
6185static int
6186ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6187{
6188 struct ftrace_graph_data *fgd;
6189 int ret;
6190
6191 if (unlikely(ftrace_disabled))
6192 return -ENODEV;
6193
6194 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6195 if (fgd == NULL)
6196 return -ENOMEM;
6197
6198 mutex_lock(&graph_lock);
6199
6200 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6201 lockdep_is_held(&graph_lock));
6202 fgd->type = GRAPH_FILTER_NOTRACE;
6203 fgd->seq_ops = &ftrace_graph_seq_ops;
6204
6205 ret = __ftrace_graph_open(inode, file, fgd);
6206 if (ret < 0)
6207 kfree(fgd);
6208
6209 mutex_unlock(&graph_lock);
6210 return ret;
6211}
6212
6213static int
6214ftrace_graph_release(struct inode *inode, struct file *file)
6215{
6216 struct ftrace_graph_data *fgd;
6217 struct ftrace_hash *old_hash, *new_hash;
6218 struct trace_parser *parser;
6219 int ret = 0;
6220
6221 if (file->f_mode & FMODE_READ) {
6222 struct seq_file *m = file->private_data;
6223
6224 fgd = m->private;
6225 seq_release(inode, file);
6226 } else {
6227 fgd = file->private_data;
6228 }
6229
6230
6231 if (file->f_mode & FMODE_WRITE) {
6232
6233 parser = &fgd->parser;
6234
6235 if (trace_parser_loaded((parser))) {
6236 ret = ftrace_graph_set_hash(fgd->new_hash,
6237 parser->buffer);
6238 }
6239
6240 trace_parser_put(parser);
6241
6242 new_hash = __ftrace_hash_move(fgd->new_hash);
6243 if (!new_hash) {
6244 ret = -ENOMEM;
6245 goto out;
6246 }
6247
6248 mutex_lock(&graph_lock);
6249
6250 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6251 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6252 lockdep_is_held(&graph_lock));
6253 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6254 } else {
6255 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6256 lockdep_is_held(&graph_lock));
6257 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6258 }
6259
6260 mutex_unlock(&graph_lock);
6261
6262 /*
6263 * We need to do a hard force of sched synchronization.
6264 * This is because we use preempt_disable() to do RCU, but
6265 * the function tracers can be called where RCU is not watching
6266 * (like before user_exit()). We can not rely on the RCU
6267 * infrastructure to do the synchronization, thus we must do it
6268 * ourselves.
6269 */
6270 if (old_hash != EMPTY_HASH)
6271 synchronize_rcu_tasks_rude();
6272
6273 free_ftrace_hash(old_hash);
6274 }
6275
6276 out:
6277 free_ftrace_hash(fgd->new_hash);
6278 kfree(fgd);
6279
6280 return ret;
6281}
6282
6283static int
6284ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6285{
6286 struct ftrace_glob func_g;
6287 struct dyn_ftrace *rec;
6288 struct ftrace_page *pg;
6289 struct ftrace_func_entry *entry;
6290 int fail = 1;
6291 int not;
6292
6293 /* decode regex */
6294 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6295 &func_g.search, ¬);
6296
6297 func_g.len = strlen(func_g.search);
6298
6299 mutex_lock(&ftrace_lock);
6300
6301 if (unlikely(ftrace_disabled)) {
6302 mutex_unlock(&ftrace_lock);
6303 return -ENODEV;
6304 }
6305
6306 do_for_each_ftrace_rec(pg, rec) {
6307
6308 if (rec->flags & FTRACE_FL_DISABLED)
6309 continue;
6310
6311 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6312 entry = ftrace_lookup_ip(hash, rec->ip);
6313
6314 if (!not) {
6315 fail = 0;
6316
6317 if (entry)
6318 continue;
6319 if (add_hash_entry(hash, rec->ip) == NULL)
6320 goto out;
6321 } else {
6322 if (entry) {
6323 free_hash_entry(hash, entry);
6324 fail = 0;
6325 }
6326 }
6327 }
6328 } while_for_each_ftrace_rec();
6329out:
6330 mutex_unlock(&ftrace_lock);
6331
6332 if (fail)
6333 return -EINVAL;
6334
6335 return 0;
6336}
6337
6338static ssize_t
6339ftrace_graph_write(struct file *file, const char __user *ubuf,
6340 size_t cnt, loff_t *ppos)
6341{
6342 ssize_t read, ret = 0;
6343 struct ftrace_graph_data *fgd = file->private_data;
6344 struct trace_parser *parser;
6345
6346 if (!cnt)
6347 return 0;
6348
6349 /* Read mode uses seq functions */
6350 if (file->f_mode & FMODE_READ) {
6351 struct seq_file *m = file->private_data;
6352 fgd = m->private;
6353 }
6354
6355 parser = &fgd->parser;
6356
6357 read = trace_get_user(parser, ubuf, cnt, ppos);
6358
6359 if (read >= 0 && trace_parser_loaded(parser) &&
6360 !trace_parser_cont(parser)) {
6361
6362 ret = ftrace_graph_set_hash(fgd->new_hash,
6363 parser->buffer);
6364 trace_parser_clear(parser);
6365 }
6366
6367 if (!ret)
6368 ret = read;
6369
6370 return ret;
6371}
6372
6373static const struct file_operations ftrace_graph_fops = {
6374 .open = ftrace_graph_open,
6375 .read = seq_read,
6376 .write = ftrace_graph_write,
6377 .llseek = tracing_lseek,
6378 .release = ftrace_graph_release,
6379};
6380
6381static const struct file_operations ftrace_graph_notrace_fops = {
6382 .open = ftrace_graph_notrace_open,
6383 .read = seq_read,
6384 .write = ftrace_graph_write,
6385 .llseek = tracing_lseek,
6386 .release = ftrace_graph_release,
6387};
6388#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6389
6390void ftrace_create_filter_files(struct ftrace_ops *ops,
6391 struct dentry *parent)
6392{
6393
6394 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6395 ops, &ftrace_filter_fops);
6396
6397 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6398 ops, &ftrace_notrace_fops);
6399}
6400
6401/*
6402 * The name "destroy_filter_files" is really a misnomer. Although
6403 * in the future, it may actually delete the files, but this is
6404 * really intended to make sure the ops passed in are disabled
6405 * and that when this function returns, the caller is free to
6406 * free the ops.
6407 *
6408 * The "destroy" name is only to match the "create" name that this
6409 * should be paired with.
6410 */
6411void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6412{
6413 mutex_lock(&ftrace_lock);
6414 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6415 ftrace_shutdown(ops, 0);
6416 ops->flags |= FTRACE_OPS_FL_DELETED;
6417 ftrace_free_filter(ops);
6418 mutex_unlock(&ftrace_lock);
6419}
6420
6421static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6422{
6423
6424 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6425 d_tracer, NULL, &ftrace_avail_fops);
6426
6427 trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6428 d_tracer, NULL, &ftrace_avail_addrs_fops);
6429
6430 trace_create_file("enabled_functions", TRACE_MODE_READ,
6431 d_tracer, NULL, &ftrace_enabled_fops);
6432
6433 trace_create_file("touched_functions", TRACE_MODE_READ,
6434 d_tracer, NULL, &ftrace_touched_fops);
6435
6436 ftrace_create_filter_files(&global_ops, d_tracer);
6437
6438#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6439 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6440 NULL,
6441 &ftrace_graph_fops);
6442 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6443 NULL,
6444 &ftrace_graph_notrace_fops);
6445#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6446
6447 return 0;
6448}
6449
6450static int ftrace_cmp_ips(const void *a, const void *b)
6451{
6452 const unsigned long *ipa = a;
6453 const unsigned long *ipb = b;
6454
6455 if (*ipa > *ipb)
6456 return 1;
6457 if (*ipa < *ipb)
6458 return -1;
6459 return 0;
6460}
6461
6462#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6463static void test_is_sorted(unsigned long *start, unsigned long count)
6464{
6465 int i;
6466
6467 for (i = 1; i < count; i++) {
6468 if (WARN(start[i - 1] > start[i],
6469 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6470 (void *)start[i - 1], start[i - 1],
6471 (void *)start[i], start[i]))
6472 break;
6473 }
6474 if (i == count)
6475 pr_info("ftrace section at %px sorted properly\n", start);
6476}
6477#else
6478static void test_is_sorted(unsigned long *start, unsigned long count)
6479{
6480}
6481#endif
6482
6483static int ftrace_process_locs(struct module *mod,
6484 unsigned long *start,
6485 unsigned long *end)
6486{
6487 struct ftrace_page *pg_unuse = NULL;
6488 struct ftrace_page *start_pg;
6489 struct ftrace_page *pg;
6490 struct dyn_ftrace *rec;
6491 unsigned long skipped = 0;
6492 unsigned long count;
6493 unsigned long *p;
6494 unsigned long addr;
6495 unsigned long flags = 0; /* Shut up gcc */
6496 int ret = -ENOMEM;
6497
6498 count = end - start;
6499
6500 if (!count)
6501 return 0;
6502
6503 /*
6504 * Sorting mcount in vmlinux at build time depend on
6505 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6506 * modules can not be sorted at build time.
6507 */
6508 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6509 sort(start, count, sizeof(*start),
6510 ftrace_cmp_ips, NULL);
6511 } else {
6512 test_is_sorted(start, count);
6513 }
6514
6515 start_pg = ftrace_allocate_pages(count);
6516 if (!start_pg)
6517 return -ENOMEM;
6518
6519 mutex_lock(&ftrace_lock);
6520
6521 /*
6522 * Core and each module needs their own pages, as
6523 * modules will free them when they are removed.
6524 * Force a new page to be allocated for modules.
6525 */
6526 if (!mod) {
6527 WARN_ON(ftrace_pages || ftrace_pages_start);
6528 /* First initialization */
6529 ftrace_pages = ftrace_pages_start = start_pg;
6530 } else {
6531 if (!ftrace_pages)
6532 goto out;
6533
6534 if (WARN_ON(ftrace_pages->next)) {
6535 /* Hmm, we have free pages? */
6536 while (ftrace_pages->next)
6537 ftrace_pages = ftrace_pages->next;
6538 }
6539
6540 ftrace_pages->next = start_pg;
6541 }
6542
6543 p = start;
6544 pg = start_pg;
6545 while (p < end) {
6546 unsigned long end_offset;
6547 addr = ftrace_call_adjust(*p++);
6548 /*
6549 * Some architecture linkers will pad between
6550 * the different mcount_loc sections of different
6551 * object files to satisfy alignments.
6552 * Skip any NULL pointers.
6553 */
6554 if (!addr) {
6555 skipped++;
6556 continue;
6557 }
6558
6559 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6560 if (end_offset > PAGE_SIZE << pg->order) {
6561 /* We should have allocated enough */
6562 if (WARN_ON(!pg->next))
6563 break;
6564 pg = pg->next;
6565 }
6566
6567 rec = &pg->records[pg->index++];
6568 rec->ip = addr;
6569 }
6570
6571 if (pg->next) {
6572 pg_unuse = pg->next;
6573 pg->next = NULL;
6574 }
6575
6576 /* Assign the last page to ftrace_pages */
6577 ftrace_pages = pg;
6578
6579 /*
6580 * We only need to disable interrupts on start up
6581 * because we are modifying code that an interrupt
6582 * may execute, and the modification is not atomic.
6583 * But for modules, nothing runs the code we modify
6584 * until we are finished with it, and there's no
6585 * reason to cause large interrupt latencies while we do it.
6586 */
6587 if (!mod)
6588 local_irq_save(flags);
6589 ftrace_update_code(mod, start_pg);
6590 if (!mod)
6591 local_irq_restore(flags);
6592 ret = 0;
6593 out:
6594 mutex_unlock(&ftrace_lock);
6595
6596 /* We should have used all pages unless we skipped some */
6597 if (pg_unuse) {
6598 WARN_ON(!skipped);
6599 /* Need to synchronize with ftrace_location_range() */
6600 synchronize_rcu();
6601 ftrace_free_pages(pg_unuse);
6602 }
6603 return ret;
6604}
6605
6606struct ftrace_mod_func {
6607 struct list_head list;
6608 char *name;
6609 unsigned long ip;
6610 unsigned int size;
6611};
6612
6613struct ftrace_mod_map {
6614 struct rcu_head rcu;
6615 struct list_head list;
6616 struct module *mod;
6617 unsigned long start_addr;
6618 unsigned long end_addr;
6619 struct list_head funcs;
6620 unsigned int num_funcs;
6621};
6622
6623static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6624 unsigned long *value, char *type,
6625 char *name, char *module_name,
6626 int *exported)
6627{
6628 struct ftrace_ops *op;
6629
6630 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6631 if (!op->trampoline || symnum--)
6632 continue;
6633 *value = op->trampoline;
6634 *type = 't';
6635 strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6636 strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6637 *exported = 0;
6638 return 0;
6639 }
6640
6641 return -ERANGE;
6642}
6643
6644#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6645/*
6646 * Check if the current ops references the given ip.
6647 *
6648 * If the ops traces all functions, then it was already accounted for.
6649 * If the ops does not trace the current record function, skip it.
6650 * If the ops ignores the function via notrace filter, skip it.
6651 */
6652static bool
6653ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6654{
6655 /* If ops isn't enabled, ignore it */
6656 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6657 return false;
6658
6659 /* If ops traces all then it includes this function */
6660 if (ops_traces_mod(ops))
6661 return true;
6662
6663 /* The function must be in the filter */
6664 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6665 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6666 return false;
6667
6668 /* If in notrace hash, we ignore it too */
6669 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6670 return false;
6671
6672 return true;
6673}
6674#endif
6675
6676#ifdef CONFIG_MODULES
6677
6678#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6679
6680static LIST_HEAD(ftrace_mod_maps);
6681
6682static int referenced_filters(struct dyn_ftrace *rec)
6683{
6684 struct ftrace_ops *ops;
6685 int cnt = 0;
6686
6687 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6688 if (ops_references_ip(ops, rec->ip)) {
6689 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6690 continue;
6691 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6692 continue;
6693 cnt++;
6694 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6695 rec->flags |= FTRACE_FL_REGS;
6696 if (cnt == 1 && ops->trampoline)
6697 rec->flags |= FTRACE_FL_TRAMP;
6698 else
6699 rec->flags &= ~FTRACE_FL_TRAMP;
6700 }
6701 }
6702
6703 return cnt;
6704}
6705
6706static void
6707clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6708{
6709 struct ftrace_func_entry *entry;
6710 struct dyn_ftrace *rec;
6711 int i;
6712
6713 if (ftrace_hash_empty(hash))
6714 return;
6715
6716 for (i = 0; i < pg->index; i++) {
6717 rec = &pg->records[i];
6718 entry = __ftrace_lookup_ip(hash, rec->ip);
6719 /*
6720 * Do not allow this rec to match again.
6721 * Yeah, it may waste some memory, but will be removed
6722 * if/when the hash is modified again.
6723 */
6724 if (entry)
6725 entry->ip = 0;
6726 }
6727}
6728
6729/* Clear any records from hashes */
6730static void clear_mod_from_hashes(struct ftrace_page *pg)
6731{
6732 struct trace_array *tr;
6733
6734 mutex_lock(&trace_types_lock);
6735 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6736 if (!tr->ops || !tr->ops->func_hash)
6737 continue;
6738 mutex_lock(&tr->ops->func_hash->regex_lock);
6739 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6740 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6741 mutex_unlock(&tr->ops->func_hash->regex_lock);
6742 }
6743 mutex_unlock(&trace_types_lock);
6744}
6745
6746static void ftrace_free_mod_map(struct rcu_head *rcu)
6747{
6748 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6749 struct ftrace_mod_func *mod_func;
6750 struct ftrace_mod_func *n;
6751
6752 /* All the contents of mod_map are now not visible to readers */
6753 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6754 kfree(mod_func->name);
6755 list_del(&mod_func->list);
6756 kfree(mod_func);
6757 }
6758
6759 kfree(mod_map);
6760}
6761
6762void ftrace_release_mod(struct module *mod)
6763{
6764 struct ftrace_mod_map *mod_map;
6765 struct ftrace_mod_map *n;
6766 struct dyn_ftrace *rec;
6767 struct ftrace_page **last_pg;
6768 struct ftrace_page *tmp_page = NULL;
6769 struct ftrace_page *pg;
6770
6771 mutex_lock(&ftrace_lock);
6772
6773 if (ftrace_disabled)
6774 goto out_unlock;
6775
6776 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6777 if (mod_map->mod == mod) {
6778 list_del_rcu(&mod_map->list);
6779 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6780 break;
6781 }
6782 }
6783
6784 /*
6785 * Each module has its own ftrace_pages, remove
6786 * them from the list.
6787 */
6788 last_pg = &ftrace_pages_start;
6789 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6790 rec = &pg->records[0];
6791 if (within_module(rec->ip, mod)) {
6792 /*
6793 * As core pages are first, the first
6794 * page should never be a module page.
6795 */
6796 if (WARN_ON(pg == ftrace_pages_start))
6797 goto out_unlock;
6798
6799 /* Check if we are deleting the last page */
6800 if (pg == ftrace_pages)
6801 ftrace_pages = next_to_ftrace_page(last_pg);
6802
6803 ftrace_update_tot_cnt -= pg->index;
6804 *last_pg = pg->next;
6805
6806 pg->next = tmp_page;
6807 tmp_page = pg;
6808 } else
6809 last_pg = &pg->next;
6810 }
6811 out_unlock:
6812 mutex_unlock(&ftrace_lock);
6813
6814 /* Need to synchronize with ftrace_location_range() */
6815 if (tmp_page)
6816 synchronize_rcu();
6817 for (pg = tmp_page; pg; pg = tmp_page) {
6818
6819 /* Needs to be called outside of ftrace_lock */
6820 clear_mod_from_hashes(pg);
6821
6822 if (pg->records) {
6823 free_pages((unsigned long)pg->records, pg->order);
6824 ftrace_number_of_pages -= 1 << pg->order;
6825 }
6826 tmp_page = pg->next;
6827 kfree(pg);
6828 ftrace_number_of_groups--;
6829 }
6830}
6831
6832void ftrace_module_enable(struct module *mod)
6833{
6834 struct dyn_ftrace *rec;
6835 struct ftrace_page *pg;
6836
6837 mutex_lock(&ftrace_lock);
6838
6839 if (ftrace_disabled)
6840 goto out_unlock;
6841
6842 /*
6843 * If the tracing is enabled, go ahead and enable the record.
6844 *
6845 * The reason not to enable the record immediately is the
6846 * inherent check of ftrace_make_nop/ftrace_make_call for
6847 * correct previous instructions. Making first the NOP
6848 * conversion puts the module to the correct state, thus
6849 * passing the ftrace_make_call check.
6850 *
6851 * We also delay this to after the module code already set the
6852 * text to read-only, as we now need to set it back to read-write
6853 * so that we can modify the text.
6854 */
6855 if (ftrace_start_up)
6856 ftrace_arch_code_modify_prepare();
6857
6858 do_for_each_ftrace_rec(pg, rec) {
6859 int cnt;
6860 /*
6861 * do_for_each_ftrace_rec() is a double loop.
6862 * module text shares the pg. If a record is
6863 * not part of this module, then skip this pg,
6864 * which the "break" will do.
6865 */
6866 if (!within_module(rec->ip, mod))
6867 break;
6868
6869 /* Weak functions should still be ignored */
6870 if (!test_for_valid_rec(rec)) {
6871 /* Clear all other flags. Should not be enabled anyway */
6872 rec->flags = FTRACE_FL_DISABLED;
6873 continue;
6874 }
6875
6876 cnt = 0;
6877
6878 /*
6879 * When adding a module, we need to check if tracers are
6880 * currently enabled and if they are, and can trace this record,
6881 * we need to enable the module functions as well as update the
6882 * reference counts for those function records.
6883 */
6884 if (ftrace_start_up)
6885 cnt += referenced_filters(rec);
6886
6887 rec->flags &= ~FTRACE_FL_DISABLED;
6888 rec->flags += cnt;
6889
6890 if (ftrace_start_up && cnt) {
6891 int failed = __ftrace_replace_code(rec, 1);
6892 if (failed) {
6893 ftrace_bug(failed, rec);
6894 goto out_loop;
6895 }
6896 }
6897
6898 } while_for_each_ftrace_rec();
6899
6900 out_loop:
6901 if (ftrace_start_up)
6902 ftrace_arch_code_modify_post_process();
6903
6904 out_unlock:
6905 mutex_unlock(&ftrace_lock);
6906
6907 process_cached_mods(mod->name);
6908}
6909
6910void ftrace_module_init(struct module *mod)
6911{
6912 int ret;
6913
6914 if (ftrace_disabled || !mod->num_ftrace_callsites)
6915 return;
6916
6917 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6918 mod->ftrace_callsites + mod->num_ftrace_callsites);
6919 if (ret)
6920 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6921 mod->name);
6922}
6923
6924static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6925 struct dyn_ftrace *rec)
6926{
6927 struct ftrace_mod_func *mod_func;
6928 unsigned long symsize;
6929 unsigned long offset;
6930 char str[KSYM_SYMBOL_LEN];
6931 char *modname;
6932 const char *ret;
6933
6934 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6935 if (!ret)
6936 return;
6937
6938 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6939 if (!mod_func)
6940 return;
6941
6942 mod_func->name = kstrdup(str, GFP_KERNEL);
6943 if (!mod_func->name) {
6944 kfree(mod_func);
6945 return;
6946 }
6947
6948 mod_func->ip = rec->ip - offset;
6949 mod_func->size = symsize;
6950
6951 mod_map->num_funcs++;
6952
6953 list_add_rcu(&mod_func->list, &mod_map->funcs);
6954}
6955
6956static struct ftrace_mod_map *
6957allocate_ftrace_mod_map(struct module *mod,
6958 unsigned long start, unsigned long end)
6959{
6960 struct ftrace_mod_map *mod_map;
6961
6962 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6963 if (!mod_map)
6964 return NULL;
6965
6966 mod_map->mod = mod;
6967 mod_map->start_addr = start;
6968 mod_map->end_addr = end;
6969 mod_map->num_funcs = 0;
6970
6971 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6972
6973 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6974
6975 return mod_map;
6976}
6977
6978static const char *
6979ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6980 unsigned long addr, unsigned long *size,
6981 unsigned long *off, char *sym)
6982{
6983 struct ftrace_mod_func *found_func = NULL;
6984 struct ftrace_mod_func *mod_func;
6985
6986 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6987 if (addr >= mod_func->ip &&
6988 addr < mod_func->ip + mod_func->size) {
6989 found_func = mod_func;
6990 break;
6991 }
6992 }
6993
6994 if (found_func) {
6995 if (size)
6996 *size = found_func->size;
6997 if (off)
6998 *off = addr - found_func->ip;
6999 if (sym)
7000 strscpy(sym, found_func->name, KSYM_NAME_LEN);
7001
7002 return found_func->name;
7003 }
7004
7005 return NULL;
7006}
7007
7008const char *
7009ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7010 unsigned long *off, char **modname, char *sym)
7011{
7012 struct ftrace_mod_map *mod_map;
7013 const char *ret = NULL;
7014
7015 /* mod_map is freed via call_rcu() */
7016 preempt_disable();
7017 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7018 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7019 if (ret) {
7020 if (modname)
7021 *modname = mod_map->mod->name;
7022 break;
7023 }
7024 }
7025 preempt_enable();
7026
7027 return ret;
7028}
7029
7030int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7031 char *type, char *name,
7032 char *module_name, int *exported)
7033{
7034 struct ftrace_mod_map *mod_map;
7035 struct ftrace_mod_func *mod_func;
7036 int ret;
7037
7038 preempt_disable();
7039 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7040
7041 if (symnum >= mod_map->num_funcs) {
7042 symnum -= mod_map->num_funcs;
7043 continue;
7044 }
7045
7046 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7047 if (symnum > 1) {
7048 symnum--;
7049 continue;
7050 }
7051
7052 *value = mod_func->ip;
7053 *type = 'T';
7054 strscpy(name, mod_func->name, KSYM_NAME_LEN);
7055 strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7056 *exported = 1;
7057 preempt_enable();
7058 return 0;
7059 }
7060 WARN_ON(1);
7061 break;
7062 }
7063 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7064 module_name, exported);
7065 preempt_enable();
7066 return ret;
7067}
7068
7069#else
7070static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7071 struct dyn_ftrace *rec) { }
7072static inline struct ftrace_mod_map *
7073allocate_ftrace_mod_map(struct module *mod,
7074 unsigned long start, unsigned long end)
7075{
7076 return NULL;
7077}
7078int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7079 char *type, char *name, char *module_name,
7080 int *exported)
7081{
7082 int ret;
7083
7084 preempt_disable();
7085 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7086 module_name, exported);
7087 preempt_enable();
7088 return ret;
7089}
7090#endif /* CONFIG_MODULES */
7091
7092struct ftrace_init_func {
7093 struct list_head list;
7094 unsigned long ip;
7095};
7096
7097/* Clear any init ips from hashes */
7098static void
7099clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7100{
7101 struct ftrace_func_entry *entry;
7102
7103 entry = ftrace_lookup_ip(hash, func->ip);
7104 /*
7105 * Do not allow this rec to match again.
7106 * Yeah, it may waste some memory, but will be removed
7107 * if/when the hash is modified again.
7108 */
7109 if (entry)
7110 entry->ip = 0;
7111}
7112
7113static void
7114clear_func_from_hashes(struct ftrace_init_func *func)
7115{
7116 struct trace_array *tr;
7117
7118 mutex_lock(&trace_types_lock);
7119 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7120 if (!tr->ops || !tr->ops->func_hash)
7121 continue;
7122 mutex_lock(&tr->ops->func_hash->regex_lock);
7123 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7124 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7125 mutex_unlock(&tr->ops->func_hash->regex_lock);
7126 }
7127 mutex_unlock(&trace_types_lock);
7128}
7129
7130static void add_to_clear_hash_list(struct list_head *clear_list,
7131 struct dyn_ftrace *rec)
7132{
7133 struct ftrace_init_func *func;
7134
7135 func = kmalloc(sizeof(*func), GFP_KERNEL);
7136 if (!func) {
7137 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7138 return;
7139 }
7140
7141 func->ip = rec->ip;
7142 list_add(&func->list, clear_list);
7143}
7144
7145void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7146{
7147 unsigned long start = (unsigned long)(start_ptr);
7148 unsigned long end = (unsigned long)(end_ptr);
7149 struct ftrace_page **last_pg = &ftrace_pages_start;
7150 struct ftrace_page *tmp_page = NULL;
7151 struct ftrace_page *pg;
7152 struct dyn_ftrace *rec;
7153 struct dyn_ftrace key;
7154 struct ftrace_mod_map *mod_map = NULL;
7155 struct ftrace_init_func *func, *func_next;
7156 LIST_HEAD(clear_hash);
7157
7158 key.ip = start;
7159 key.flags = end; /* overload flags, as it is unsigned long */
7160
7161 mutex_lock(&ftrace_lock);
7162
7163 /*
7164 * If we are freeing module init memory, then check if
7165 * any tracer is active. If so, we need to save a mapping of
7166 * the module functions being freed with the address.
7167 */
7168 if (mod && ftrace_ops_list != &ftrace_list_end)
7169 mod_map = allocate_ftrace_mod_map(mod, start, end);
7170
7171 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7172 if (end < pg->records[0].ip ||
7173 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7174 continue;
7175 again:
7176 rec = bsearch(&key, pg->records, pg->index,
7177 sizeof(struct dyn_ftrace),
7178 ftrace_cmp_recs);
7179 if (!rec)
7180 continue;
7181
7182 /* rec will be cleared from hashes after ftrace_lock unlock */
7183 add_to_clear_hash_list(&clear_hash, rec);
7184
7185 if (mod_map)
7186 save_ftrace_mod_rec(mod_map, rec);
7187
7188 pg->index--;
7189 ftrace_update_tot_cnt--;
7190 if (!pg->index) {
7191 *last_pg = pg->next;
7192 pg->next = tmp_page;
7193 tmp_page = pg;
7194 pg = container_of(last_pg, struct ftrace_page, next);
7195 if (!(*last_pg))
7196 ftrace_pages = pg;
7197 continue;
7198 }
7199 memmove(rec, rec + 1,
7200 (pg->index - (rec - pg->records)) * sizeof(*rec));
7201 /* More than one function may be in this block */
7202 goto again;
7203 }
7204 mutex_unlock(&ftrace_lock);
7205
7206 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7207 clear_func_from_hashes(func);
7208 kfree(func);
7209 }
7210 /* Need to synchronize with ftrace_location_range() */
7211 if (tmp_page) {
7212 synchronize_rcu();
7213 ftrace_free_pages(tmp_page);
7214 }
7215}
7216
7217void __init ftrace_free_init_mem(void)
7218{
7219 void *start = (void *)(&__init_begin);
7220 void *end = (void *)(&__init_end);
7221
7222 ftrace_boot_snapshot();
7223
7224 ftrace_free_mem(NULL, start, end);
7225}
7226
7227int __init __weak ftrace_dyn_arch_init(void)
7228{
7229 return 0;
7230}
7231
7232void __init ftrace_init(void)
7233{
7234 extern unsigned long __start_mcount_loc[];
7235 extern unsigned long __stop_mcount_loc[];
7236 unsigned long count, flags;
7237 int ret;
7238
7239 local_irq_save(flags);
7240 ret = ftrace_dyn_arch_init();
7241 local_irq_restore(flags);
7242 if (ret)
7243 goto failed;
7244
7245 count = __stop_mcount_loc - __start_mcount_loc;
7246 if (!count) {
7247 pr_info("ftrace: No functions to be traced?\n");
7248 goto failed;
7249 }
7250
7251 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7252 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7253
7254 ret = ftrace_process_locs(NULL,
7255 __start_mcount_loc,
7256 __stop_mcount_loc);
7257 if (ret) {
7258 pr_warn("ftrace: failed to allocate entries for functions\n");
7259 goto failed;
7260 }
7261
7262 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7263 ftrace_number_of_pages, ftrace_number_of_groups);
7264
7265 last_ftrace_enabled = ftrace_enabled = 1;
7266
7267 set_ftrace_early_filters();
7268
7269 return;
7270 failed:
7271 ftrace_disabled = 1;
7272}
7273
7274/* Do nothing if arch does not support this */
7275void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7276{
7277}
7278
7279static void ftrace_update_trampoline(struct ftrace_ops *ops)
7280{
7281 unsigned long trampoline = ops->trampoline;
7282
7283 arch_ftrace_update_trampoline(ops);
7284 if (ops->trampoline && ops->trampoline != trampoline &&
7285 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7286 /* Add to kallsyms before the perf events */
7287 ftrace_add_trampoline_to_kallsyms(ops);
7288 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7289 ops->trampoline, ops->trampoline_size, false,
7290 FTRACE_TRAMPOLINE_SYM);
7291 /*
7292 * Record the perf text poke event after the ksymbol register
7293 * event.
7294 */
7295 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7296 (void *)ops->trampoline,
7297 ops->trampoline_size);
7298 }
7299}
7300
7301void ftrace_init_trace_array(struct trace_array *tr)
7302{
7303 INIT_LIST_HEAD(&tr->func_probes);
7304 INIT_LIST_HEAD(&tr->mod_trace);
7305 INIT_LIST_HEAD(&tr->mod_notrace);
7306}
7307#else
7308
7309struct ftrace_ops global_ops = {
7310 .func = ftrace_stub,
7311 .flags = FTRACE_OPS_FL_INITIALIZED |
7312 FTRACE_OPS_FL_PID,
7313};
7314
7315static int __init ftrace_nodyn_init(void)
7316{
7317 ftrace_enabled = 1;
7318 return 0;
7319}
7320core_initcall(ftrace_nodyn_init);
7321
7322static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7323static inline void ftrace_startup_all(int command) { }
7324
7325static void ftrace_update_trampoline(struct ftrace_ops *ops)
7326{
7327}
7328
7329#endif /* CONFIG_DYNAMIC_FTRACE */
7330
7331__init void ftrace_init_global_array_ops(struct trace_array *tr)
7332{
7333 tr->ops = &global_ops;
7334 tr->ops->private = tr;
7335 ftrace_init_trace_array(tr);
7336}
7337
7338void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7339{
7340 /* If we filter on pids, update to use the pid function */
7341 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7342 if (WARN_ON(tr->ops->func != ftrace_stub))
7343 printk("ftrace ops had %pS for function\n",
7344 tr->ops->func);
7345 }
7346 tr->ops->func = func;
7347 tr->ops->private = tr;
7348}
7349
7350void ftrace_reset_array_ops(struct trace_array *tr)
7351{
7352 tr->ops->func = ftrace_stub;
7353}
7354
7355static nokprobe_inline void
7356__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7357 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7358{
7359 struct pt_regs *regs = ftrace_get_regs(fregs);
7360 struct ftrace_ops *op;
7361 int bit;
7362
7363 /*
7364 * The ftrace_test_and_set_recursion() will disable preemption,
7365 * which is required since some of the ops may be dynamically
7366 * allocated, they must be freed after a synchronize_rcu().
7367 */
7368 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7369 if (bit < 0)
7370 return;
7371
7372 do_for_each_ftrace_op(op, ftrace_ops_list) {
7373 /* Stub functions don't need to be called nor tested */
7374 if (op->flags & FTRACE_OPS_FL_STUB)
7375 continue;
7376 /*
7377 * Check the following for each ops before calling their func:
7378 * if RCU flag is set, then rcu_is_watching() must be true
7379 * Otherwise test if the ip matches the ops filter
7380 *
7381 * If any of the above fails then the op->func() is not executed.
7382 */
7383 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7384 ftrace_ops_test(op, ip, regs)) {
7385 if (FTRACE_WARN_ON(!op->func)) {
7386 pr_warn("op=%p %pS\n", op, op);
7387 goto out;
7388 }
7389 op->func(ip, parent_ip, op, fregs);
7390 }
7391 } while_for_each_ftrace_op(op);
7392out:
7393 trace_clear_recursion(bit);
7394}
7395
7396/*
7397 * Some archs only support passing ip and parent_ip. Even though
7398 * the list function ignores the op parameter, we do not want any
7399 * C side effects, where a function is called without the caller
7400 * sending a third parameter.
7401 * Archs are to support both the regs and ftrace_ops at the same time.
7402 * If they support ftrace_ops, it is assumed they support regs.
7403 * If call backs want to use regs, they must either check for regs
7404 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7405 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7406 * An architecture can pass partial regs with ftrace_ops and still
7407 * set the ARCH_SUPPORTS_FTRACE_OPS.
7408 *
7409 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7410 * arch_ftrace_ops_list_func.
7411 */
7412#if ARCH_SUPPORTS_FTRACE_OPS
7413void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7414 struct ftrace_ops *op, struct ftrace_regs *fregs)
7415{
7416 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7417}
7418#else
7419void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7420{
7421 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7422}
7423#endif
7424NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7425
7426/*
7427 * If there's only one function registered but it does not support
7428 * recursion, needs RCU protection, then this function will be called
7429 * by the mcount trampoline.
7430 */
7431static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7432 struct ftrace_ops *op, struct ftrace_regs *fregs)
7433{
7434 int bit;
7435
7436 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7437 if (bit < 0)
7438 return;
7439
7440 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7441 op->func(ip, parent_ip, op, fregs);
7442
7443 trace_clear_recursion(bit);
7444}
7445NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7446
7447/**
7448 * ftrace_ops_get_func - get the function a trampoline should call
7449 * @ops: the ops to get the function for
7450 *
7451 * Normally the mcount trampoline will call the ops->func, but there
7452 * are times that it should not. For example, if the ops does not
7453 * have its own recursion protection, then it should call the
7454 * ftrace_ops_assist_func() instead.
7455 *
7456 * Returns: the function that the trampoline should call for @ops.
7457 */
7458ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7459{
7460 /*
7461 * If the function does not handle recursion or needs to be RCU safe,
7462 * then we need to call the assist handler.
7463 */
7464 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7465 FTRACE_OPS_FL_RCU))
7466 return ftrace_ops_assist_func;
7467
7468 return ops->func;
7469}
7470
7471static void
7472ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7473 struct task_struct *prev,
7474 struct task_struct *next,
7475 unsigned int prev_state)
7476{
7477 struct trace_array *tr = data;
7478 struct trace_pid_list *pid_list;
7479 struct trace_pid_list *no_pid_list;
7480
7481 pid_list = rcu_dereference_sched(tr->function_pids);
7482 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7483
7484 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7485 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7486 FTRACE_PID_IGNORE);
7487 else
7488 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7489 next->pid);
7490}
7491
7492static void
7493ftrace_pid_follow_sched_process_fork(void *data,
7494 struct task_struct *self,
7495 struct task_struct *task)
7496{
7497 struct trace_pid_list *pid_list;
7498 struct trace_array *tr = data;
7499
7500 pid_list = rcu_dereference_sched(tr->function_pids);
7501 trace_filter_add_remove_task(pid_list, self, task);
7502
7503 pid_list = rcu_dereference_sched(tr->function_no_pids);
7504 trace_filter_add_remove_task(pid_list, self, task);
7505}
7506
7507static void
7508ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7509{
7510 struct trace_pid_list *pid_list;
7511 struct trace_array *tr = data;
7512
7513 pid_list = rcu_dereference_sched(tr->function_pids);
7514 trace_filter_add_remove_task(pid_list, NULL, task);
7515
7516 pid_list = rcu_dereference_sched(tr->function_no_pids);
7517 trace_filter_add_remove_task(pid_list, NULL, task);
7518}
7519
7520void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7521{
7522 if (enable) {
7523 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7524 tr);
7525 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7526 tr);
7527 } else {
7528 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7529 tr);
7530 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7531 tr);
7532 }
7533}
7534
7535static void clear_ftrace_pids(struct trace_array *tr, int type)
7536{
7537 struct trace_pid_list *pid_list;
7538 struct trace_pid_list *no_pid_list;
7539 int cpu;
7540
7541 pid_list = rcu_dereference_protected(tr->function_pids,
7542 lockdep_is_held(&ftrace_lock));
7543 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7544 lockdep_is_held(&ftrace_lock));
7545
7546 /* Make sure there's something to do */
7547 if (!pid_type_enabled(type, pid_list, no_pid_list))
7548 return;
7549
7550 /* See if the pids still need to be checked after this */
7551 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7552 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7553 for_each_possible_cpu(cpu)
7554 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7555 }
7556
7557 if (type & TRACE_PIDS)
7558 rcu_assign_pointer(tr->function_pids, NULL);
7559
7560 if (type & TRACE_NO_PIDS)
7561 rcu_assign_pointer(tr->function_no_pids, NULL);
7562
7563 /* Wait till all users are no longer using pid filtering */
7564 synchronize_rcu();
7565
7566 if ((type & TRACE_PIDS) && pid_list)
7567 trace_pid_list_free(pid_list);
7568
7569 if ((type & TRACE_NO_PIDS) && no_pid_list)
7570 trace_pid_list_free(no_pid_list);
7571}
7572
7573void ftrace_clear_pids(struct trace_array *tr)
7574{
7575 mutex_lock(&ftrace_lock);
7576
7577 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7578
7579 mutex_unlock(&ftrace_lock);
7580}
7581
7582static void ftrace_pid_reset(struct trace_array *tr, int type)
7583{
7584 mutex_lock(&ftrace_lock);
7585 clear_ftrace_pids(tr, type);
7586
7587 ftrace_update_pid_func();
7588 ftrace_startup_all(0);
7589
7590 mutex_unlock(&ftrace_lock);
7591}
7592
7593/* Greater than any max PID */
7594#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7595
7596static void *fpid_start(struct seq_file *m, loff_t *pos)
7597 __acquires(RCU)
7598{
7599 struct trace_pid_list *pid_list;
7600 struct trace_array *tr = m->private;
7601
7602 mutex_lock(&ftrace_lock);
7603 rcu_read_lock_sched();
7604
7605 pid_list = rcu_dereference_sched(tr->function_pids);
7606
7607 if (!pid_list)
7608 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7609
7610 return trace_pid_start(pid_list, pos);
7611}
7612
7613static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7614{
7615 struct trace_array *tr = m->private;
7616 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7617
7618 if (v == FTRACE_NO_PIDS) {
7619 (*pos)++;
7620 return NULL;
7621 }
7622 return trace_pid_next(pid_list, v, pos);
7623}
7624
7625static void fpid_stop(struct seq_file *m, void *p)
7626 __releases(RCU)
7627{
7628 rcu_read_unlock_sched();
7629 mutex_unlock(&ftrace_lock);
7630}
7631
7632static int fpid_show(struct seq_file *m, void *v)
7633{
7634 if (v == FTRACE_NO_PIDS) {
7635 seq_puts(m, "no pid\n");
7636 return 0;
7637 }
7638
7639 return trace_pid_show(m, v);
7640}
7641
7642static const struct seq_operations ftrace_pid_sops = {
7643 .start = fpid_start,
7644 .next = fpid_next,
7645 .stop = fpid_stop,
7646 .show = fpid_show,
7647};
7648
7649static void *fnpid_start(struct seq_file *m, loff_t *pos)
7650 __acquires(RCU)
7651{
7652 struct trace_pid_list *pid_list;
7653 struct trace_array *tr = m->private;
7654
7655 mutex_lock(&ftrace_lock);
7656 rcu_read_lock_sched();
7657
7658 pid_list = rcu_dereference_sched(tr->function_no_pids);
7659
7660 if (!pid_list)
7661 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7662
7663 return trace_pid_start(pid_list, pos);
7664}
7665
7666static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7667{
7668 struct trace_array *tr = m->private;
7669 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7670
7671 if (v == FTRACE_NO_PIDS) {
7672 (*pos)++;
7673 return NULL;
7674 }
7675 return trace_pid_next(pid_list, v, pos);
7676}
7677
7678static const struct seq_operations ftrace_no_pid_sops = {
7679 .start = fnpid_start,
7680 .next = fnpid_next,
7681 .stop = fpid_stop,
7682 .show = fpid_show,
7683};
7684
7685static int pid_open(struct inode *inode, struct file *file, int type)
7686{
7687 const struct seq_operations *seq_ops;
7688 struct trace_array *tr = inode->i_private;
7689 struct seq_file *m;
7690 int ret = 0;
7691
7692 ret = tracing_check_open_get_tr(tr);
7693 if (ret)
7694 return ret;
7695
7696 if ((file->f_mode & FMODE_WRITE) &&
7697 (file->f_flags & O_TRUNC))
7698 ftrace_pid_reset(tr, type);
7699
7700 switch (type) {
7701 case TRACE_PIDS:
7702 seq_ops = &ftrace_pid_sops;
7703 break;
7704 case TRACE_NO_PIDS:
7705 seq_ops = &ftrace_no_pid_sops;
7706 break;
7707 default:
7708 trace_array_put(tr);
7709 WARN_ON_ONCE(1);
7710 return -EINVAL;
7711 }
7712
7713 ret = seq_open(file, seq_ops);
7714 if (ret < 0) {
7715 trace_array_put(tr);
7716 } else {
7717 m = file->private_data;
7718 /* copy tr over to seq ops */
7719 m->private = tr;
7720 }
7721
7722 return ret;
7723}
7724
7725static int
7726ftrace_pid_open(struct inode *inode, struct file *file)
7727{
7728 return pid_open(inode, file, TRACE_PIDS);
7729}
7730
7731static int
7732ftrace_no_pid_open(struct inode *inode, struct file *file)
7733{
7734 return pid_open(inode, file, TRACE_NO_PIDS);
7735}
7736
7737static void ignore_task_cpu(void *data)
7738{
7739 struct trace_array *tr = data;
7740 struct trace_pid_list *pid_list;
7741 struct trace_pid_list *no_pid_list;
7742
7743 /*
7744 * This function is called by on_each_cpu() while the
7745 * event_mutex is held.
7746 */
7747 pid_list = rcu_dereference_protected(tr->function_pids,
7748 mutex_is_locked(&ftrace_lock));
7749 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7750 mutex_is_locked(&ftrace_lock));
7751
7752 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7753 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7754 FTRACE_PID_IGNORE);
7755 else
7756 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7757 current->pid);
7758}
7759
7760static ssize_t
7761pid_write(struct file *filp, const char __user *ubuf,
7762 size_t cnt, loff_t *ppos, int type)
7763{
7764 struct seq_file *m = filp->private_data;
7765 struct trace_array *tr = m->private;
7766 struct trace_pid_list *filtered_pids;
7767 struct trace_pid_list *other_pids;
7768 struct trace_pid_list *pid_list;
7769 ssize_t ret;
7770
7771 if (!cnt)
7772 return 0;
7773
7774 mutex_lock(&ftrace_lock);
7775
7776 switch (type) {
7777 case TRACE_PIDS:
7778 filtered_pids = rcu_dereference_protected(tr->function_pids,
7779 lockdep_is_held(&ftrace_lock));
7780 other_pids = rcu_dereference_protected(tr->function_no_pids,
7781 lockdep_is_held(&ftrace_lock));
7782 break;
7783 case TRACE_NO_PIDS:
7784 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7785 lockdep_is_held(&ftrace_lock));
7786 other_pids = rcu_dereference_protected(tr->function_pids,
7787 lockdep_is_held(&ftrace_lock));
7788 break;
7789 default:
7790 ret = -EINVAL;
7791 WARN_ON_ONCE(1);
7792 goto out;
7793 }
7794
7795 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7796 if (ret < 0)
7797 goto out;
7798
7799 switch (type) {
7800 case TRACE_PIDS:
7801 rcu_assign_pointer(tr->function_pids, pid_list);
7802 break;
7803 case TRACE_NO_PIDS:
7804 rcu_assign_pointer(tr->function_no_pids, pid_list);
7805 break;
7806 }
7807
7808
7809 if (filtered_pids) {
7810 synchronize_rcu();
7811 trace_pid_list_free(filtered_pids);
7812 } else if (pid_list && !other_pids) {
7813 /* Register a probe to set whether to ignore the tracing of a task */
7814 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7815 }
7816
7817 /*
7818 * Ignoring of pids is done at task switch. But we have to
7819 * check for those tasks that are currently running.
7820 * Always do this in case a pid was appended or removed.
7821 */
7822 on_each_cpu(ignore_task_cpu, tr, 1);
7823
7824 ftrace_update_pid_func();
7825 ftrace_startup_all(0);
7826 out:
7827 mutex_unlock(&ftrace_lock);
7828
7829 if (ret > 0)
7830 *ppos += ret;
7831
7832 return ret;
7833}
7834
7835static ssize_t
7836ftrace_pid_write(struct file *filp, const char __user *ubuf,
7837 size_t cnt, loff_t *ppos)
7838{
7839 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7840}
7841
7842static ssize_t
7843ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7844 size_t cnt, loff_t *ppos)
7845{
7846 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7847}
7848
7849static int
7850ftrace_pid_release(struct inode *inode, struct file *file)
7851{
7852 struct trace_array *tr = inode->i_private;
7853
7854 trace_array_put(tr);
7855
7856 return seq_release(inode, file);
7857}
7858
7859static const struct file_operations ftrace_pid_fops = {
7860 .open = ftrace_pid_open,
7861 .write = ftrace_pid_write,
7862 .read = seq_read,
7863 .llseek = tracing_lseek,
7864 .release = ftrace_pid_release,
7865};
7866
7867static const struct file_operations ftrace_no_pid_fops = {
7868 .open = ftrace_no_pid_open,
7869 .write = ftrace_no_pid_write,
7870 .read = seq_read,
7871 .llseek = tracing_lseek,
7872 .release = ftrace_pid_release,
7873};
7874
7875void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7876{
7877 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7878 tr, &ftrace_pid_fops);
7879 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7880 d_tracer, tr, &ftrace_no_pid_fops);
7881}
7882
7883void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7884 struct dentry *d_tracer)
7885{
7886 /* Only the top level directory has the dyn_tracefs and profile */
7887 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7888
7889 ftrace_init_dyn_tracefs(d_tracer);
7890 ftrace_profile_tracefs(d_tracer);
7891}
7892
7893/**
7894 * ftrace_kill - kill ftrace
7895 *
7896 * This function should be used by panic code. It stops ftrace
7897 * but in a not so nice way. If you need to simply kill ftrace
7898 * from a non-atomic section, use ftrace_kill.
7899 */
7900void ftrace_kill(void)
7901{
7902 ftrace_disabled = 1;
7903 ftrace_enabled = 0;
7904 ftrace_trace_function = ftrace_stub;
7905}
7906
7907/**
7908 * ftrace_is_dead - Test if ftrace is dead or not.
7909 *
7910 * Returns: 1 if ftrace is "dead", zero otherwise.
7911 */
7912int ftrace_is_dead(void)
7913{
7914 return ftrace_disabled;
7915}
7916
7917#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7918/*
7919 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7920 * it doesn't conflict with any direct ftrace_ops. If there is existing
7921 * direct ftrace_ops on a kernel function being patched, call
7922 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7923 *
7924 * @ops: ftrace_ops being registered.
7925 *
7926 * Returns:
7927 * 0 on success;
7928 * Negative on failure.
7929 */
7930static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7931{
7932 struct ftrace_func_entry *entry;
7933 struct ftrace_hash *hash;
7934 struct ftrace_ops *op;
7935 int size, i, ret;
7936
7937 lockdep_assert_held_once(&direct_mutex);
7938
7939 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7940 return 0;
7941
7942 hash = ops->func_hash->filter_hash;
7943 size = 1 << hash->size_bits;
7944 for (i = 0; i < size; i++) {
7945 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7946 unsigned long ip = entry->ip;
7947 bool found_op = false;
7948
7949 mutex_lock(&ftrace_lock);
7950 do_for_each_ftrace_op(op, ftrace_ops_list) {
7951 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7952 continue;
7953 if (ops_references_ip(op, ip)) {
7954 found_op = true;
7955 break;
7956 }
7957 } while_for_each_ftrace_op(op);
7958 mutex_unlock(&ftrace_lock);
7959
7960 if (found_op) {
7961 if (!op->ops_func)
7962 return -EBUSY;
7963
7964 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7965 if (ret)
7966 return ret;
7967 }
7968 }
7969 }
7970
7971 return 0;
7972}
7973
7974/*
7975 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7976 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7977 * ops.
7978 */
7979static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7980{
7981 struct ftrace_func_entry *entry;
7982 struct ftrace_hash *hash;
7983 struct ftrace_ops *op;
7984 int size, i;
7985
7986 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7987 return;
7988
7989 mutex_lock(&direct_mutex);
7990
7991 hash = ops->func_hash->filter_hash;
7992 size = 1 << hash->size_bits;
7993 for (i = 0; i < size; i++) {
7994 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7995 unsigned long ip = entry->ip;
7996 bool found_op = false;
7997
7998 mutex_lock(&ftrace_lock);
7999 do_for_each_ftrace_op(op, ftrace_ops_list) {
8000 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8001 continue;
8002 if (ops_references_ip(op, ip)) {
8003 found_op = true;
8004 break;
8005 }
8006 } while_for_each_ftrace_op(op);
8007 mutex_unlock(&ftrace_lock);
8008
8009 /* The cleanup is optional, ignore any errors */
8010 if (found_op && op->ops_func)
8011 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8012 }
8013 }
8014 mutex_unlock(&direct_mutex);
8015}
8016
8017#define lock_direct_mutex() mutex_lock(&direct_mutex)
8018#define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8019
8020#else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8021
8022static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8023{
8024 return 0;
8025}
8026
8027static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8028{
8029}
8030
8031#define lock_direct_mutex() do { } while (0)
8032#define unlock_direct_mutex() do { } while (0)
8033
8034#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8035
8036/*
8037 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8038 */
8039static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8040{
8041 int ret;
8042
8043 ftrace_ops_init(ops);
8044
8045 mutex_lock(&ftrace_lock);
8046
8047 ret = ftrace_startup(ops, 0);
8048
8049 mutex_unlock(&ftrace_lock);
8050
8051 return ret;
8052}
8053
8054/**
8055 * register_ftrace_function - register a function for profiling
8056 * @ops: ops structure that holds the function for profiling.
8057 *
8058 * Register a function to be called by all functions in the
8059 * kernel.
8060 *
8061 * Note: @ops->func and all the functions it calls must be labeled
8062 * with "notrace", otherwise it will go into a
8063 * recursive loop.
8064 */
8065int register_ftrace_function(struct ftrace_ops *ops)
8066{
8067 int ret;
8068
8069 lock_direct_mutex();
8070 ret = prepare_direct_functions_for_ipmodify(ops);
8071 if (ret < 0)
8072 goto out_unlock;
8073
8074 ret = register_ftrace_function_nolock(ops);
8075
8076out_unlock:
8077 unlock_direct_mutex();
8078 return ret;
8079}
8080EXPORT_SYMBOL_GPL(register_ftrace_function);
8081
8082/**
8083 * unregister_ftrace_function - unregister a function for profiling.
8084 * @ops: ops structure that holds the function to unregister
8085 *
8086 * Unregister a function that was added to be called by ftrace profiling.
8087 */
8088int unregister_ftrace_function(struct ftrace_ops *ops)
8089{
8090 int ret;
8091
8092 mutex_lock(&ftrace_lock);
8093 ret = ftrace_shutdown(ops, 0);
8094 mutex_unlock(&ftrace_lock);
8095
8096 cleanup_direct_functions_after_ipmodify(ops);
8097 return ret;
8098}
8099EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8100
8101static int symbols_cmp(const void *a, const void *b)
8102{
8103 const char **str_a = (const char **) a;
8104 const char **str_b = (const char **) b;
8105
8106 return strcmp(*str_a, *str_b);
8107}
8108
8109struct kallsyms_data {
8110 unsigned long *addrs;
8111 const char **syms;
8112 size_t cnt;
8113 size_t found;
8114};
8115
8116/* This function gets called for all kernel and module symbols
8117 * and returns 1 in case we resolved all the requested symbols,
8118 * 0 otherwise.
8119 */
8120static int kallsyms_callback(void *data, const char *name, unsigned long addr)
8121{
8122 struct kallsyms_data *args = data;
8123 const char **sym;
8124 int idx;
8125
8126 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8127 if (!sym)
8128 return 0;
8129
8130 idx = sym - args->syms;
8131 if (args->addrs[idx])
8132 return 0;
8133
8134 if (!ftrace_location(addr))
8135 return 0;
8136
8137 args->addrs[idx] = addr;
8138 args->found++;
8139 return args->found == args->cnt ? 1 : 0;
8140}
8141
8142/**
8143 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8144 *
8145 * @sorted_syms: array of symbols pointers symbols to resolve,
8146 * must be alphabetically sorted
8147 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8148 * @addrs: array for storing resulting addresses
8149 *
8150 * This function looks up addresses for array of symbols provided in
8151 * @syms array (must be alphabetically sorted) and stores them in
8152 * @addrs array, which needs to be big enough to store at least @cnt
8153 * addresses.
8154 *
8155 * Returns: 0 if all provided symbols are found, -ESRCH otherwise.
8156 */
8157int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8158{
8159 struct kallsyms_data args;
8160 int found_all;
8161
8162 memset(addrs, 0, sizeof(*addrs) * cnt);
8163 args.addrs = addrs;
8164 args.syms = sorted_syms;
8165 args.cnt = cnt;
8166 args.found = 0;
8167
8168 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8169 if (found_all)
8170 return 0;
8171 found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8172 return found_all ? 0 : -ESRCH;
8173}
8174
8175#ifdef CONFIG_SYSCTL
8176
8177#ifdef CONFIG_DYNAMIC_FTRACE
8178static void ftrace_startup_sysctl(void)
8179{
8180 int command;
8181
8182 if (unlikely(ftrace_disabled))
8183 return;
8184
8185 /* Force update next time */
8186 saved_ftrace_func = NULL;
8187 /* ftrace_start_up is true if we want ftrace running */
8188 if (ftrace_start_up) {
8189 command = FTRACE_UPDATE_CALLS;
8190 if (ftrace_graph_active)
8191 command |= FTRACE_START_FUNC_RET;
8192 ftrace_startup_enable(command);
8193 }
8194}
8195
8196static void ftrace_shutdown_sysctl(void)
8197{
8198 int command;
8199
8200 if (unlikely(ftrace_disabled))
8201 return;
8202
8203 /* ftrace_start_up is true if ftrace is running */
8204 if (ftrace_start_up) {
8205 command = FTRACE_DISABLE_CALLS;
8206 if (ftrace_graph_active)
8207 command |= FTRACE_STOP_FUNC_RET;
8208 ftrace_run_update_code(command);
8209 }
8210}
8211#else
8212# define ftrace_startup_sysctl() do { } while (0)
8213# define ftrace_shutdown_sysctl() do { } while (0)
8214#endif /* CONFIG_DYNAMIC_FTRACE */
8215
8216static bool is_permanent_ops_registered(void)
8217{
8218 struct ftrace_ops *op;
8219
8220 do_for_each_ftrace_op(op, ftrace_ops_list) {
8221 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8222 return true;
8223 } while_for_each_ftrace_op(op);
8224
8225 return false;
8226}
8227
8228static int
8229ftrace_enable_sysctl(struct ctl_table *table, int write,
8230 void *buffer, size_t *lenp, loff_t *ppos)
8231{
8232 int ret = -ENODEV;
8233
8234 mutex_lock(&ftrace_lock);
8235
8236 if (unlikely(ftrace_disabled))
8237 goto out;
8238
8239 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8240
8241 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8242 goto out;
8243
8244 if (ftrace_enabled) {
8245
8246 /* we are starting ftrace again */
8247 if (rcu_dereference_protected(ftrace_ops_list,
8248 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8249 update_ftrace_function();
8250
8251 ftrace_startup_sysctl();
8252
8253 } else {
8254 if (is_permanent_ops_registered()) {
8255 ftrace_enabled = true;
8256 ret = -EBUSY;
8257 goto out;
8258 }
8259
8260 /* stopping ftrace calls (just send to ftrace_stub) */
8261 ftrace_trace_function = ftrace_stub;
8262
8263 ftrace_shutdown_sysctl();
8264 }
8265
8266 last_ftrace_enabled = !!ftrace_enabled;
8267 out:
8268 mutex_unlock(&ftrace_lock);
8269 return ret;
8270}
8271
8272static struct ctl_table ftrace_sysctls[] = {
8273 {
8274 .procname = "ftrace_enabled",
8275 .data = &ftrace_enabled,
8276 .maxlen = sizeof(int),
8277 .mode = 0644,
8278 .proc_handler = ftrace_enable_sysctl,
8279 },
8280 {}
8281};
8282
8283static int __init ftrace_sysctl_init(void)
8284{
8285 register_sysctl_init("kernel", ftrace_sysctls);
8286 return 0;
8287}
8288late_initcall(ftrace_sysctl_init);
8289#endif