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