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