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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// 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_INVALID_FUNCTION "__ftrace_invalid_address__"
49
50#define FTRACE_WARN_ON(cond) \
51 ({ \
52 int ___r = cond; \
53 if (WARN_ON(___r)) \
54 ftrace_kill(); \
55 ___r; \
56 })
57
58#define FTRACE_WARN_ON_ONCE(cond) \
59 ({ \
60 int ___r = cond; \
61 if (WARN_ON_ONCE(___r)) \
62 ftrace_kill(); \
63 ___r; \
64 })
65
66/* hash bits for specific function selection */
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_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 __maybe_unused 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 || tr->function_no_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/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
125void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
126 struct ftrace_ops *op, struct ftrace_regs *fregs);
127
128static inline void ftrace_ops_init(struct ftrace_ops *ops)
129{
130#ifdef CONFIG_DYNAMIC_FTRACE
131 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
132 mutex_init(&ops->local_hash.regex_lock);
133 ops->func_hash = &ops->local_hash;
134 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
135 }
136#endif
137}
138
139static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
140 struct ftrace_ops *op, struct ftrace_regs *fregs)
141{
142 struct trace_array *tr = op->private;
143 int pid;
144
145 if (tr) {
146 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
147 if (pid == FTRACE_PID_IGNORE)
148 return;
149 if (pid != FTRACE_PID_TRACE &&
150 pid != current->pid)
151 return;
152 }
153
154 op->saved_func(ip, parent_ip, op, fregs);
155}
156
157static void ftrace_sync_ipi(void *data)
158{
159 /* Probably not needed, but do it anyway */
160 smp_rmb();
161}
162
163static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
164{
165 /*
166 * If this is a dynamic or RCU ops, or we force list func,
167 * then it needs to call the list anyway.
168 */
169 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
170 FTRACE_FORCE_LIST_FUNC)
171 return ftrace_ops_list_func;
172
173 return ftrace_ops_get_func(ops);
174}
175
176static void update_ftrace_function(void)
177{
178 ftrace_func_t func;
179
180 /*
181 * Prepare the ftrace_ops that the arch callback will use.
182 * If there's only one ftrace_ops registered, the ftrace_ops_list
183 * will point to the ops we want.
184 */
185 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
186 lockdep_is_held(&ftrace_lock));
187
188 /* If there's no ftrace_ops registered, just call the stub function */
189 if (set_function_trace_op == &ftrace_list_end) {
190 func = ftrace_stub;
191
192 /*
193 * If we are at the end of the list and this ops is
194 * recursion safe and not dynamic and the arch supports passing ops,
195 * then have the mcount trampoline call the function directly.
196 */
197 } else if (rcu_dereference_protected(ftrace_ops_list->next,
198 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
199 func = ftrace_ops_get_list_func(ftrace_ops_list);
200
201 } else {
202 /* Just use the default ftrace_ops */
203 set_function_trace_op = &ftrace_list_end;
204 func = ftrace_ops_list_func;
205 }
206
207 update_function_graph_func();
208
209 /* If there's no change, then do nothing more here */
210 if (ftrace_trace_function == func)
211 return;
212
213 /*
214 * If we are using the list function, it doesn't care
215 * about the function_trace_ops.
216 */
217 if (func == ftrace_ops_list_func) {
218 ftrace_trace_function = func;
219 /*
220 * Don't even bother setting function_trace_ops,
221 * it would be racy to do so anyway.
222 */
223 return;
224 }
225
226#ifndef CONFIG_DYNAMIC_FTRACE
227 /*
228 * For static tracing, we need to be a bit more careful.
229 * The function change takes affect immediately. Thus,
230 * we need to coordinate the setting of the function_trace_ops
231 * with the setting of the ftrace_trace_function.
232 *
233 * Set the function to the list ops, which will call the
234 * function we want, albeit indirectly, but it handles the
235 * ftrace_ops and doesn't depend on function_trace_op.
236 */
237 ftrace_trace_function = ftrace_ops_list_func;
238 /*
239 * Make sure all CPUs see this. Yes this is slow, but static
240 * tracing is slow and nasty to have enabled.
241 */
242 synchronize_rcu_tasks_rude();
243 /* Now all cpus are using the list ops. */
244 function_trace_op = set_function_trace_op;
245 /* Make sure the function_trace_op is visible on all CPUs */
246 smp_wmb();
247 /* Nasty way to force a rmb on all cpus */
248 smp_call_function(ftrace_sync_ipi, NULL, 1);
249 /* OK, we are all set to update the ftrace_trace_function now! */
250#endif /* !CONFIG_DYNAMIC_FTRACE */
251
252 ftrace_trace_function = func;
253}
254
255static void add_ftrace_ops(struct ftrace_ops __rcu **list,
256 struct ftrace_ops *ops)
257{
258 rcu_assign_pointer(ops->next, *list);
259
260 /*
261 * We are entering ops into the list but another
262 * CPU might be walking that list. We need to make sure
263 * the ops->next pointer is valid before another CPU sees
264 * the ops pointer included into the list.
265 */
266 rcu_assign_pointer(*list, ops);
267}
268
269static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
270 struct ftrace_ops *ops)
271{
272 struct ftrace_ops **p;
273
274 /*
275 * If we are removing the last function, then simply point
276 * to the ftrace_stub.
277 */
278 if (rcu_dereference_protected(*list,
279 lockdep_is_held(&ftrace_lock)) == ops &&
280 rcu_dereference_protected(ops->next,
281 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
282 *list = &ftrace_list_end;
283 return 0;
284 }
285
286 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
287 if (*p == ops)
288 break;
289
290 if (*p != ops)
291 return -1;
292
293 *p = (*p)->next;
294 return 0;
295}
296
297static void ftrace_update_trampoline(struct ftrace_ops *ops);
298
299int __register_ftrace_function(struct ftrace_ops *ops)
300{
301 if (ops->flags & FTRACE_OPS_FL_DELETED)
302 return -EINVAL;
303
304 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
305 return -EBUSY;
306
307#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
308 /*
309 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
310 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
311 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
312 */
313 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
314 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
315 return -EINVAL;
316
317 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
318 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
319#endif
320 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
321 return -EBUSY;
322
323 if (!is_kernel_core_data((unsigned long)ops))
324 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
325
326 add_ftrace_ops(&ftrace_ops_list, ops);
327
328 /* Always save the function, and reset at unregistering */
329 ops->saved_func = ops->func;
330
331 if (ftrace_pids_enabled(ops))
332 ops->func = ftrace_pid_func;
333
334 ftrace_update_trampoline(ops);
335
336 if (ftrace_enabled)
337 update_ftrace_function();
338
339 return 0;
340}
341
342int __unregister_ftrace_function(struct ftrace_ops *ops)
343{
344 int ret;
345
346 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
347 return -EBUSY;
348
349 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
350
351 if (ret < 0)
352 return ret;
353
354 if (ftrace_enabled)
355 update_ftrace_function();
356
357 ops->func = ops->saved_func;
358
359 return 0;
360}
361
362static void ftrace_update_pid_func(void)
363{
364 struct ftrace_ops *op;
365
366 /* Only do something if we are tracing something */
367 if (ftrace_trace_function == ftrace_stub)
368 return;
369
370 do_for_each_ftrace_op(op, ftrace_ops_list) {
371 if (op->flags & FTRACE_OPS_FL_PID) {
372 op->func = ftrace_pids_enabled(op) ?
373 ftrace_pid_func : op->saved_func;
374 ftrace_update_trampoline(op);
375 }
376 } while_for_each_ftrace_op(op);
377
378 update_ftrace_function();
379}
380
381#ifdef CONFIG_FUNCTION_PROFILER
382struct ftrace_profile {
383 struct hlist_node node;
384 unsigned long ip;
385 unsigned long counter;
386#ifdef CONFIG_FUNCTION_GRAPH_TRACER
387 unsigned long long time;
388 unsigned long long time_squared;
389#endif
390};
391
392struct ftrace_profile_page {
393 struct ftrace_profile_page *next;
394 unsigned long index;
395 struct ftrace_profile records[];
396};
397
398struct ftrace_profile_stat {
399 atomic_t disabled;
400 struct hlist_head *hash;
401 struct ftrace_profile_page *pages;
402 struct ftrace_profile_page *start;
403 struct tracer_stat stat;
404};
405
406#define PROFILE_RECORDS_SIZE \
407 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
408
409#define PROFILES_PER_PAGE \
410 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
411
412static int ftrace_profile_enabled __read_mostly;
413
414/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
415static DEFINE_MUTEX(ftrace_profile_lock);
416
417static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
418
419#define FTRACE_PROFILE_HASH_BITS 10
420#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
421
422static void *
423function_stat_next(void *v, int idx)
424{
425 struct ftrace_profile *rec = v;
426 struct ftrace_profile_page *pg;
427
428 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
429
430 again:
431 if (idx != 0)
432 rec++;
433
434 if ((void *)rec >= (void *)&pg->records[pg->index]) {
435 pg = pg->next;
436 if (!pg)
437 return NULL;
438 rec = &pg->records[0];
439 if (!rec->counter)
440 goto again;
441 }
442
443 return rec;
444}
445
446static void *function_stat_start(struct tracer_stat *trace)
447{
448 struct ftrace_profile_stat *stat =
449 container_of(trace, struct ftrace_profile_stat, stat);
450
451 if (!stat || !stat->start)
452 return NULL;
453
454 return function_stat_next(&stat->start->records[0], 0);
455}
456
457#ifdef CONFIG_FUNCTION_GRAPH_TRACER
458/* function graph compares on total time */
459static int function_stat_cmp(const void *p1, const void *p2)
460{
461 const struct ftrace_profile *a = p1;
462 const struct ftrace_profile *b = p2;
463
464 if (a->time < b->time)
465 return -1;
466 if (a->time > b->time)
467 return 1;
468 else
469 return 0;
470}
471#else
472/* not function graph compares against hits */
473static int function_stat_cmp(const void *p1, const void *p2)
474{
475 const struct ftrace_profile *a = p1;
476 const struct ftrace_profile *b = p2;
477
478 if (a->counter < b->counter)
479 return -1;
480 if (a->counter > b->counter)
481 return 1;
482 else
483 return 0;
484}
485#endif
486
487static int function_stat_headers(struct seq_file *m)
488{
489#ifdef CONFIG_FUNCTION_GRAPH_TRACER
490 seq_puts(m, " Function "
491 "Hit Time Avg s^2\n"
492 " -------- "
493 "--- ---- --- ---\n");
494#else
495 seq_puts(m, " Function Hit\n"
496 " -------- ---\n");
497#endif
498 return 0;
499}
500
501static int function_stat_show(struct seq_file *m, void *v)
502{
503 struct ftrace_profile *rec = v;
504 char str[KSYM_SYMBOL_LEN];
505 int ret = 0;
506#ifdef CONFIG_FUNCTION_GRAPH_TRACER
507 static struct trace_seq s;
508 unsigned long long avg;
509 unsigned long long stddev;
510#endif
511 mutex_lock(&ftrace_profile_lock);
512
513 /* we raced with function_profile_reset() */
514 if (unlikely(rec->counter == 0)) {
515 ret = -EBUSY;
516 goto out;
517 }
518
519#ifdef CONFIG_FUNCTION_GRAPH_TRACER
520 avg = div64_ul(rec->time, rec->counter);
521 if (tracing_thresh && (avg < tracing_thresh))
522 goto out;
523#endif
524
525 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
526 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
527
528#ifdef CONFIG_FUNCTION_GRAPH_TRACER
529 seq_puts(m, " ");
530
531 /* Sample standard deviation (s^2) */
532 if (rec->counter <= 1)
533 stddev = 0;
534 else {
535 /*
536 * Apply Welford's method:
537 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
538 */
539 stddev = rec->counter * rec->time_squared -
540 rec->time * rec->time;
541
542 /*
543 * Divide only 1000 for ns^2 -> us^2 conversion.
544 * trace_print_graph_duration will divide 1000 again.
545 */
546 stddev = div64_ul(stddev,
547 rec->counter * (rec->counter - 1) * 1000);
548 }
549
550 trace_seq_init(&s);
551 trace_print_graph_duration(rec->time, &s);
552 trace_seq_puts(&s, " ");
553 trace_print_graph_duration(avg, &s);
554 trace_seq_puts(&s, " ");
555 trace_print_graph_duration(stddev, &s);
556 trace_print_seq(m, &s);
557#endif
558 seq_putc(m, '\n');
559out:
560 mutex_unlock(&ftrace_profile_lock);
561
562 return ret;
563}
564
565static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
566{
567 struct ftrace_profile_page *pg;
568
569 pg = stat->pages = stat->start;
570
571 while (pg) {
572 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
573 pg->index = 0;
574 pg = pg->next;
575 }
576
577 memset(stat->hash, 0,
578 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
579}
580
581static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
582{
583 struct ftrace_profile_page *pg;
584 int functions;
585 int pages;
586 int i;
587
588 /* If we already allocated, do nothing */
589 if (stat->pages)
590 return 0;
591
592 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
593 if (!stat->pages)
594 return -ENOMEM;
595
596#ifdef CONFIG_DYNAMIC_FTRACE
597 functions = ftrace_update_tot_cnt;
598#else
599 /*
600 * We do not know the number of functions that exist because
601 * dynamic tracing is what counts them. With past experience
602 * we have around 20K functions. That should be more than enough.
603 * It is highly unlikely we will execute every function in
604 * the kernel.
605 */
606 functions = 20000;
607#endif
608
609 pg = stat->start = stat->pages;
610
611 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
612
613 for (i = 1; i < pages; i++) {
614 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
615 if (!pg->next)
616 goto out_free;
617 pg = pg->next;
618 }
619
620 return 0;
621
622 out_free:
623 pg = stat->start;
624 while (pg) {
625 unsigned long tmp = (unsigned long)pg;
626
627 pg = pg->next;
628 free_page(tmp);
629 }
630
631 stat->pages = NULL;
632 stat->start = NULL;
633
634 return -ENOMEM;
635}
636
637static int ftrace_profile_init_cpu(int cpu)
638{
639 struct ftrace_profile_stat *stat;
640 int size;
641
642 stat = &per_cpu(ftrace_profile_stats, cpu);
643
644 if (stat->hash) {
645 /* If the profile is already created, simply reset it */
646 ftrace_profile_reset(stat);
647 return 0;
648 }
649
650 /*
651 * We are profiling all functions, but usually only a few thousand
652 * functions are hit. We'll make a hash of 1024 items.
653 */
654 size = FTRACE_PROFILE_HASH_SIZE;
655
656 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
657
658 if (!stat->hash)
659 return -ENOMEM;
660
661 /* Preallocate the function profiling pages */
662 if (ftrace_profile_pages_init(stat) < 0) {
663 kfree(stat->hash);
664 stat->hash = NULL;
665 return -ENOMEM;
666 }
667
668 return 0;
669}
670
671static int ftrace_profile_init(void)
672{
673 int cpu;
674 int ret = 0;
675
676 for_each_possible_cpu(cpu) {
677 ret = ftrace_profile_init_cpu(cpu);
678 if (ret)
679 break;
680 }
681
682 return ret;
683}
684
685/* interrupts must be disabled */
686static struct ftrace_profile *
687ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
688{
689 struct ftrace_profile *rec;
690 struct hlist_head *hhd;
691 unsigned long key;
692
693 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
694 hhd = &stat->hash[key];
695
696 if (hlist_empty(hhd))
697 return NULL;
698
699 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
700 if (rec->ip == ip)
701 return rec;
702 }
703
704 return NULL;
705}
706
707static void ftrace_add_profile(struct ftrace_profile_stat *stat,
708 struct ftrace_profile *rec)
709{
710 unsigned long key;
711
712 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
713 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
714}
715
716/*
717 * The memory is already allocated, this simply finds a new record to use.
718 */
719static struct ftrace_profile *
720ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
721{
722 struct ftrace_profile *rec = NULL;
723
724 /* prevent recursion (from NMIs) */
725 if (atomic_inc_return(&stat->disabled) != 1)
726 goto out;
727
728 /*
729 * Try to find the function again since an NMI
730 * could have added it
731 */
732 rec = ftrace_find_profiled_func(stat, ip);
733 if (rec)
734 goto out;
735
736 if (stat->pages->index == PROFILES_PER_PAGE) {
737 if (!stat->pages->next)
738 goto out;
739 stat->pages = stat->pages->next;
740 }
741
742 rec = &stat->pages->records[stat->pages->index++];
743 rec->ip = ip;
744 ftrace_add_profile(stat, rec);
745
746 out:
747 atomic_dec(&stat->disabled);
748
749 return rec;
750}
751
752static void
753function_profile_call(unsigned long ip, unsigned long parent_ip,
754 struct ftrace_ops *ops, struct ftrace_regs *fregs)
755{
756 struct ftrace_profile_stat *stat;
757 struct ftrace_profile *rec;
758 unsigned long flags;
759
760 if (!ftrace_profile_enabled)
761 return;
762
763 local_irq_save(flags);
764
765 stat = this_cpu_ptr(&ftrace_profile_stats);
766 if (!stat->hash || !ftrace_profile_enabled)
767 goto out;
768
769 rec = ftrace_find_profiled_func(stat, ip);
770 if (!rec) {
771 rec = ftrace_profile_alloc(stat, ip);
772 if (!rec)
773 goto out;
774 }
775
776 rec->counter++;
777 out:
778 local_irq_restore(flags);
779}
780
781#ifdef CONFIG_FUNCTION_GRAPH_TRACER
782static bool fgraph_graph_time = true;
783
784void ftrace_graph_graph_time_control(bool enable)
785{
786 fgraph_graph_time = enable;
787}
788
789static int profile_graph_entry(struct ftrace_graph_ent *trace)
790{
791 struct ftrace_ret_stack *ret_stack;
792
793 function_profile_call(trace->func, 0, NULL, NULL);
794
795 /* If function graph is shutting down, ret_stack can be NULL */
796 if (!current->ret_stack)
797 return 0;
798
799 ret_stack = ftrace_graph_get_ret_stack(current, 0);
800 if (ret_stack)
801 ret_stack->subtime = 0;
802
803 return 1;
804}
805
806static void profile_graph_return(struct ftrace_graph_ret *trace)
807{
808 struct ftrace_ret_stack *ret_stack;
809 struct ftrace_profile_stat *stat;
810 unsigned long long calltime;
811 struct ftrace_profile *rec;
812 unsigned long flags;
813
814 local_irq_save(flags);
815 stat = this_cpu_ptr(&ftrace_profile_stats);
816 if (!stat->hash || !ftrace_profile_enabled)
817 goto out;
818
819 /* If the calltime was zero'd ignore it */
820 if (!trace->calltime)
821 goto out;
822
823 calltime = trace->rettime - trace->calltime;
824
825 if (!fgraph_graph_time) {
826
827 /* Append this call time to the parent time to subtract */
828 ret_stack = ftrace_graph_get_ret_stack(current, 1);
829 if (ret_stack)
830 ret_stack->subtime += calltime;
831
832 ret_stack = ftrace_graph_get_ret_stack(current, 0);
833 if (ret_stack && ret_stack->subtime < calltime)
834 calltime -= ret_stack->subtime;
835 else
836 calltime = 0;
837 }
838
839 rec = ftrace_find_profiled_func(stat, trace->func);
840 if (rec) {
841 rec->time += calltime;
842 rec->time_squared += calltime * calltime;
843 }
844
845 out:
846 local_irq_restore(flags);
847}
848
849static struct fgraph_ops fprofiler_ops = {
850 .entryfunc = &profile_graph_entry,
851 .retfunc = &profile_graph_return,
852};
853
854static int register_ftrace_profiler(void)
855{
856 return register_ftrace_graph(&fprofiler_ops);
857}
858
859static void unregister_ftrace_profiler(void)
860{
861 unregister_ftrace_graph(&fprofiler_ops);
862}
863#else
864static struct ftrace_ops ftrace_profile_ops __read_mostly = {
865 .func = function_profile_call,
866 .flags = FTRACE_OPS_FL_INITIALIZED,
867 INIT_OPS_HASH(ftrace_profile_ops)
868};
869
870static int register_ftrace_profiler(void)
871{
872 return register_ftrace_function(&ftrace_profile_ops);
873}
874
875static void unregister_ftrace_profiler(void)
876{
877 unregister_ftrace_function(&ftrace_profile_ops);
878}
879#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
880
881static ssize_t
882ftrace_profile_write(struct file *filp, const char __user *ubuf,
883 size_t cnt, loff_t *ppos)
884{
885 unsigned long val;
886 int ret;
887
888 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
889 if (ret)
890 return ret;
891
892 val = !!val;
893
894 mutex_lock(&ftrace_profile_lock);
895 if (ftrace_profile_enabled ^ val) {
896 if (val) {
897 ret = ftrace_profile_init();
898 if (ret < 0) {
899 cnt = ret;
900 goto out;
901 }
902
903 ret = register_ftrace_profiler();
904 if (ret < 0) {
905 cnt = ret;
906 goto out;
907 }
908 ftrace_profile_enabled = 1;
909 } else {
910 ftrace_profile_enabled = 0;
911 /*
912 * unregister_ftrace_profiler calls stop_machine
913 * so this acts like an synchronize_rcu.
914 */
915 unregister_ftrace_profiler();
916 }
917 }
918 out:
919 mutex_unlock(&ftrace_profile_lock);
920
921 *ppos += cnt;
922
923 return cnt;
924}
925
926static ssize_t
927ftrace_profile_read(struct file *filp, char __user *ubuf,
928 size_t cnt, loff_t *ppos)
929{
930 char buf[64]; /* big enough to hold a number */
931 int r;
932
933 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
934 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
935}
936
937static const struct file_operations ftrace_profile_fops = {
938 .open = tracing_open_generic,
939 .read = ftrace_profile_read,
940 .write = ftrace_profile_write,
941 .llseek = default_llseek,
942};
943
944/* used to initialize the real stat files */
945static struct tracer_stat function_stats __initdata = {
946 .name = "functions",
947 .stat_start = function_stat_start,
948 .stat_next = function_stat_next,
949 .stat_cmp = function_stat_cmp,
950 .stat_headers = function_stat_headers,
951 .stat_show = function_stat_show
952};
953
954static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
955{
956 struct ftrace_profile_stat *stat;
957 char *name;
958 int ret;
959 int cpu;
960
961 for_each_possible_cpu(cpu) {
962 stat = &per_cpu(ftrace_profile_stats, cpu);
963
964 name = kasprintf(GFP_KERNEL, "function%d", cpu);
965 if (!name) {
966 /*
967 * The files created are permanent, if something happens
968 * we still do not free memory.
969 */
970 WARN(1,
971 "Could not allocate stat file for cpu %d\n",
972 cpu);
973 return;
974 }
975 stat->stat = function_stats;
976 stat->stat.name = name;
977 ret = register_stat_tracer(&stat->stat);
978 if (ret) {
979 WARN(1,
980 "Could not register function stat for cpu %d\n",
981 cpu);
982 kfree(name);
983 return;
984 }
985 }
986
987 trace_create_file("function_profile_enabled",
988 TRACE_MODE_WRITE, d_tracer, NULL,
989 &ftrace_profile_fops);
990}
991
992#else /* CONFIG_FUNCTION_PROFILER */
993static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
994{
995}
996#endif /* CONFIG_FUNCTION_PROFILER */
997
998#ifdef CONFIG_DYNAMIC_FTRACE
999
1000static struct ftrace_ops *removed_ops;
1001
1002/*
1003 * Set when doing a global update, like enabling all recs or disabling them.
1004 * It is not set when just updating a single ftrace_ops.
1005 */
1006static bool update_all_ops;
1007
1008#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1009# error Dynamic ftrace depends on MCOUNT_RECORD
1010#endif
1011
1012struct ftrace_func_probe {
1013 struct ftrace_probe_ops *probe_ops;
1014 struct ftrace_ops ops;
1015 struct trace_array *tr;
1016 struct list_head list;
1017 void *data;
1018 int ref;
1019};
1020
1021/*
1022 * We make these constant because no one should touch them,
1023 * but they are used as the default "empty hash", to avoid allocating
1024 * it all the time. These are in a read only section such that if
1025 * anyone does try to modify it, it will cause an exception.
1026 */
1027static const struct hlist_head empty_buckets[1];
1028static const struct ftrace_hash empty_hash = {
1029 .buckets = (struct hlist_head *)empty_buckets,
1030};
1031#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1032
1033struct ftrace_ops global_ops = {
1034 .func = ftrace_stub,
1035 .local_hash.notrace_hash = EMPTY_HASH,
1036 .local_hash.filter_hash = EMPTY_HASH,
1037 INIT_OPS_HASH(global_ops)
1038 .flags = FTRACE_OPS_FL_INITIALIZED |
1039 FTRACE_OPS_FL_PID,
1040};
1041
1042/*
1043 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1044 */
1045struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1046{
1047 struct ftrace_ops *op = NULL;
1048
1049 /*
1050 * Some of the ops may be dynamically allocated,
1051 * they are freed after a synchronize_rcu().
1052 */
1053 preempt_disable_notrace();
1054
1055 do_for_each_ftrace_op(op, ftrace_ops_list) {
1056 /*
1057 * This is to check for dynamically allocated trampolines.
1058 * Trampolines that are in kernel text will have
1059 * core_kernel_text() return true.
1060 */
1061 if (op->trampoline && op->trampoline_size)
1062 if (addr >= op->trampoline &&
1063 addr < op->trampoline + op->trampoline_size) {
1064 preempt_enable_notrace();
1065 return op;
1066 }
1067 } while_for_each_ftrace_op(op);
1068 preempt_enable_notrace();
1069
1070 return NULL;
1071}
1072
1073/*
1074 * This is used by __kernel_text_address() to return true if the
1075 * address is on a dynamically allocated trampoline that would
1076 * not return true for either core_kernel_text() or
1077 * is_module_text_address().
1078 */
1079bool is_ftrace_trampoline(unsigned long addr)
1080{
1081 return ftrace_ops_trampoline(addr) != NULL;
1082}
1083
1084struct ftrace_page {
1085 struct ftrace_page *next;
1086 struct dyn_ftrace *records;
1087 int index;
1088 int order;
1089};
1090
1091#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1092#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1093
1094static struct ftrace_page *ftrace_pages_start;
1095static struct ftrace_page *ftrace_pages;
1096
1097static __always_inline unsigned long
1098ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1099{
1100 if (hash->size_bits > 0)
1101 return hash_long(ip, hash->size_bits);
1102
1103 return 0;
1104}
1105
1106/* Only use this function if ftrace_hash_empty() has already been tested */
1107static __always_inline struct ftrace_func_entry *
1108__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1109{
1110 unsigned long key;
1111 struct ftrace_func_entry *entry;
1112 struct hlist_head *hhd;
1113
1114 key = ftrace_hash_key(hash, ip);
1115 hhd = &hash->buckets[key];
1116
1117 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1118 if (entry->ip == ip)
1119 return entry;
1120 }
1121 return NULL;
1122}
1123
1124/**
1125 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1126 * @hash: The hash to look at
1127 * @ip: The instruction pointer to test
1128 *
1129 * Search a given @hash to see if a given instruction pointer (@ip)
1130 * exists in it.
1131 *
1132 * Returns the entry that holds the @ip if found. NULL otherwise.
1133 */
1134struct ftrace_func_entry *
1135ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1136{
1137 if (ftrace_hash_empty(hash))
1138 return NULL;
1139
1140 return __ftrace_lookup_ip(hash, ip);
1141}
1142
1143static void __add_hash_entry(struct ftrace_hash *hash,
1144 struct ftrace_func_entry *entry)
1145{
1146 struct hlist_head *hhd;
1147 unsigned long key;
1148
1149 key = ftrace_hash_key(hash, entry->ip);
1150 hhd = &hash->buckets[key];
1151 hlist_add_head(&entry->hlist, hhd);
1152 hash->count++;
1153}
1154
1155static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1156{
1157 struct ftrace_func_entry *entry;
1158
1159 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1160 if (!entry)
1161 return -ENOMEM;
1162
1163 entry->ip = ip;
1164 __add_hash_entry(hash, entry);
1165
1166 return 0;
1167}
1168
1169static void
1170free_hash_entry(struct ftrace_hash *hash,
1171 struct ftrace_func_entry *entry)
1172{
1173 hlist_del(&entry->hlist);
1174 kfree(entry);
1175 hash->count--;
1176}
1177
1178static void
1179remove_hash_entry(struct ftrace_hash *hash,
1180 struct ftrace_func_entry *entry)
1181{
1182 hlist_del_rcu(&entry->hlist);
1183 hash->count--;
1184}
1185
1186static void ftrace_hash_clear(struct ftrace_hash *hash)
1187{
1188 struct hlist_head *hhd;
1189 struct hlist_node *tn;
1190 struct ftrace_func_entry *entry;
1191 int size = 1 << hash->size_bits;
1192 int i;
1193
1194 if (!hash->count)
1195 return;
1196
1197 for (i = 0; i < size; i++) {
1198 hhd = &hash->buckets[i];
1199 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1200 free_hash_entry(hash, entry);
1201 }
1202 FTRACE_WARN_ON(hash->count);
1203}
1204
1205static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1206{
1207 list_del(&ftrace_mod->list);
1208 kfree(ftrace_mod->module);
1209 kfree(ftrace_mod->func);
1210 kfree(ftrace_mod);
1211}
1212
1213static void clear_ftrace_mod_list(struct list_head *head)
1214{
1215 struct ftrace_mod_load *p, *n;
1216
1217 /* stack tracer isn't supported yet */
1218 if (!head)
1219 return;
1220
1221 mutex_lock(&ftrace_lock);
1222 list_for_each_entry_safe(p, n, head, list)
1223 free_ftrace_mod(p);
1224 mutex_unlock(&ftrace_lock);
1225}
1226
1227static void free_ftrace_hash(struct ftrace_hash *hash)
1228{
1229 if (!hash || hash == EMPTY_HASH)
1230 return;
1231 ftrace_hash_clear(hash);
1232 kfree(hash->buckets);
1233 kfree(hash);
1234}
1235
1236static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1237{
1238 struct ftrace_hash *hash;
1239
1240 hash = container_of(rcu, struct ftrace_hash, rcu);
1241 free_ftrace_hash(hash);
1242}
1243
1244static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1245{
1246 if (!hash || hash == EMPTY_HASH)
1247 return;
1248 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1249}
1250
1251/**
1252 * ftrace_free_filter - remove all filters for an ftrace_ops
1253 * @ops - the ops to remove the filters from
1254 */
1255void ftrace_free_filter(struct ftrace_ops *ops)
1256{
1257 ftrace_ops_init(ops);
1258 free_ftrace_hash(ops->func_hash->filter_hash);
1259 free_ftrace_hash(ops->func_hash->notrace_hash);
1260}
1261EXPORT_SYMBOL_GPL(ftrace_free_filter);
1262
1263static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1264{
1265 struct ftrace_hash *hash;
1266 int size;
1267
1268 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1269 if (!hash)
1270 return NULL;
1271
1272 size = 1 << size_bits;
1273 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1274
1275 if (!hash->buckets) {
1276 kfree(hash);
1277 return NULL;
1278 }
1279
1280 hash->size_bits = size_bits;
1281
1282 return hash;
1283}
1284
1285
1286static int ftrace_add_mod(struct trace_array *tr,
1287 const char *func, const char *module,
1288 int enable)
1289{
1290 struct ftrace_mod_load *ftrace_mod;
1291 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1292
1293 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1294 if (!ftrace_mod)
1295 return -ENOMEM;
1296
1297 INIT_LIST_HEAD(&ftrace_mod->list);
1298 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1299 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1300 ftrace_mod->enable = enable;
1301
1302 if (!ftrace_mod->func || !ftrace_mod->module)
1303 goto out_free;
1304
1305 list_add(&ftrace_mod->list, mod_head);
1306
1307 return 0;
1308
1309 out_free:
1310 free_ftrace_mod(ftrace_mod);
1311
1312 return -ENOMEM;
1313}
1314
1315static struct ftrace_hash *
1316alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1317{
1318 struct ftrace_func_entry *entry;
1319 struct ftrace_hash *new_hash;
1320 int size;
1321 int ret;
1322 int i;
1323
1324 new_hash = alloc_ftrace_hash(size_bits);
1325 if (!new_hash)
1326 return NULL;
1327
1328 if (hash)
1329 new_hash->flags = hash->flags;
1330
1331 /* Empty hash? */
1332 if (ftrace_hash_empty(hash))
1333 return new_hash;
1334
1335 size = 1 << hash->size_bits;
1336 for (i = 0; i < size; i++) {
1337 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1338 ret = add_hash_entry(new_hash, entry->ip);
1339 if (ret < 0)
1340 goto free_hash;
1341 }
1342 }
1343
1344 FTRACE_WARN_ON(new_hash->count != hash->count);
1345
1346 return new_hash;
1347
1348 free_hash:
1349 free_ftrace_hash(new_hash);
1350 return NULL;
1351}
1352
1353static void
1354ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1355static void
1356ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1357
1358static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1359 struct ftrace_hash *new_hash);
1360
1361static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1362{
1363 struct ftrace_func_entry *entry;
1364 struct ftrace_hash *new_hash;
1365 struct hlist_head *hhd;
1366 struct hlist_node *tn;
1367 int bits = 0;
1368 int i;
1369
1370 /*
1371 * Use around half the size (max bit of it), but
1372 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1373 */
1374 bits = fls(size / 2);
1375
1376 /* Don't allocate too much */
1377 if (bits > FTRACE_HASH_MAX_BITS)
1378 bits = FTRACE_HASH_MAX_BITS;
1379
1380 new_hash = alloc_ftrace_hash(bits);
1381 if (!new_hash)
1382 return NULL;
1383
1384 new_hash->flags = src->flags;
1385
1386 size = 1 << src->size_bits;
1387 for (i = 0; i < size; i++) {
1388 hhd = &src->buckets[i];
1389 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1390 remove_hash_entry(src, entry);
1391 __add_hash_entry(new_hash, entry);
1392 }
1393 }
1394 return new_hash;
1395}
1396
1397static struct ftrace_hash *
1398__ftrace_hash_move(struct ftrace_hash *src)
1399{
1400 int size = src->count;
1401
1402 /*
1403 * If the new source is empty, just return the empty_hash.
1404 */
1405 if (ftrace_hash_empty(src))
1406 return EMPTY_HASH;
1407
1408 return dup_hash(src, size);
1409}
1410
1411static int
1412ftrace_hash_move(struct ftrace_ops *ops, int enable,
1413 struct ftrace_hash **dst, struct ftrace_hash *src)
1414{
1415 struct ftrace_hash *new_hash;
1416 int ret;
1417
1418 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1419 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1420 return -EINVAL;
1421
1422 new_hash = __ftrace_hash_move(src);
1423 if (!new_hash)
1424 return -ENOMEM;
1425
1426 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1427 if (enable) {
1428 /* IPMODIFY should be updated only when filter_hash updating */
1429 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1430 if (ret < 0) {
1431 free_ftrace_hash(new_hash);
1432 return ret;
1433 }
1434 }
1435
1436 /*
1437 * Remove the current set, update the hash and add
1438 * them back.
1439 */
1440 ftrace_hash_rec_disable_modify(ops, enable);
1441
1442 rcu_assign_pointer(*dst, new_hash);
1443
1444 ftrace_hash_rec_enable_modify(ops, enable);
1445
1446 return 0;
1447}
1448
1449static bool hash_contains_ip(unsigned long ip,
1450 struct ftrace_ops_hash *hash)
1451{
1452 /*
1453 * The function record is a match if it exists in the filter
1454 * hash and not in the notrace hash. Note, an empty hash is
1455 * considered a match for the filter hash, but an empty
1456 * notrace hash is considered not in the notrace hash.
1457 */
1458 return (ftrace_hash_empty(hash->filter_hash) ||
1459 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1460 (ftrace_hash_empty(hash->notrace_hash) ||
1461 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1462}
1463
1464/*
1465 * Test the hashes for this ops to see if we want to call
1466 * the ops->func or not.
1467 *
1468 * It's a match if the ip is in the ops->filter_hash or
1469 * the filter_hash does not exist or is empty,
1470 * AND
1471 * the ip is not in the ops->notrace_hash.
1472 *
1473 * This needs to be called with preemption disabled as
1474 * the hashes are freed with call_rcu().
1475 */
1476int
1477ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1478{
1479 struct ftrace_ops_hash hash;
1480 int ret;
1481
1482#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1483 /*
1484 * There's a small race when adding ops that the ftrace handler
1485 * that wants regs, may be called without them. We can not
1486 * allow that handler to be called if regs is NULL.
1487 */
1488 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1489 return 0;
1490#endif
1491
1492 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1493 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1494
1495 if (hash_contains_ip(ip, &hash))
1496 ret = 1;
1497 else
1498 ret = 0;
1499
1500 return ret;
1501}
1502
1503/*
1504 * This is a double for. Do not use 'break' to break out of the loop,
1505 * you must use a goto.
1506 */
1507#define do_for_each_ftrace_rec(pg, rec) \
1508 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1509 int _____i; \
1510 for (_____i = 0; _____i < pg->index; _____i++) { \
1511 rec = &pg->records[_____i];
1512
1513#define while_for_each_ftrace_rec() \
1514 } \
1515 }
1516
1517
1518static int ftrace_cmp_recs(const void *a, const void *b)
1519{
1520 const struct dyn_ftrace *key = a;
1521 const struct dyn_ftrace *rec = b;
1522
1523 if (key->flags < rec->ip)
1524 return -1;
1525 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1526 return 1;
1527 return 0;
1528}
1529
1530static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1531{
1532 struct ftrace_page *pg;
1533 struct dyn_ftrace *rec = NULL;
1534 struct dyn_ftrace key;
1535
1536 key.ip = start;
1537 key.flags = end; /* overload flags, as it is unsigned long */
1538
1539 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1540 if (end < pg->records[0].ip ||
1541 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1542 continue;
1543 rec = bsearch(&key, pg->records, pg->index,
1544 sizeof(struct dyn_ftrace),
1545 ftrace_cmp_recs);
1546 if (rec)
1547 break;
1548 }
1549 return rec;
1550}
1551
1552/**
1553 * ftrace_location_range - return the first address of a traced location
1554 * if it touches the given ip range
1555 * @start: start of range to search.
1556 * @end: end of range to search (inclusive). @end points to the last byte
1557 * to check.
1558 *
1559 * Returns rec->ip if the related ftrace location is a least partly within
1560 * the given address range. That is, the first address of the instruction
1561 * that is either a NOP or call to the function tracer. It checks the ftrace
1562 * internal tables to determine if the address belongs or not.
1563 */
1564unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1565{
1566 struct dyn_ftrace *rec;
1567
1568 rec = lookup_rec(start, end);
1569 if (rec)
1570 return rec->ip;
1571
1572 return 0;
1573}
1574
1575/**
1576 * ftrace_location - return the ftrace location
1577 * @ip: the instruction pointer to check
1578 *
1579 * If @ip matches the ftrace location, return @ip.
1580 * If @ip matches sym+0, return sym's ftrace location.
1581 * Otherwise, return 0.
1582 */
1583unsigned long ftrace_location(unsigned long ip)
1584{
1585 struct dyn_ftrace *rec;
1586 unsigned long offset;
1587 unsigned long size;
1588
1589 rec = lookup_rec(ip, ip);
1590 if (!rec) {
1591 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1592 goto out;
1593
1594 /* map sym+0 to __fentry__ */
1595 if (!offset)
1596 rec = lookup_rec(ip, ip + size - 1);
1597 }
1598
1599 if (rec)
1600 return rec->ip;
1601
1602out:
1603 return 0;
1604}
1605
1606/**
1607 * ftrace_text_reserved - return true if range contains an ftrace location
1608 * @start: start of range to search
1609 * @end: end of range to search (inclusive). @end points to the last byte to check.
1610 *
1611 * Returns 1 if @start and @end contains a ftrace location.
1612 * That is, the instruction that is either a NOP or call to
1613 * the function tracer. It checks the ftrace internal tables to
1614 * determine if the address belongs or not.
1615 */
1616int ftrace_text_reserved(const void *start, const void *end)
1617{
1618 unsigned long ret;
1619
1620 ret = ftrace_location_range((unsigned long)start,
1621 (unsigned long)end);
1622
1623 return (int)!!ret;
1624}
1625
1626/* Test if ops registered to this rec needs regs */
1627static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1628{
1629 struct ftrace_ops *ops;
1630 bool keep_regs = false;
1631
1632 for (ops = ftrace_ops_list;
1633 ops != &ftrace_list_end; ops = ops->next) {
1634 /* pass rec in as regs to have non-NULL val */
1635 if (ftrace_ops_test(ops, rec->ip, rec)) {
1636 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1637 keep_regs = true;
1638 break;
1639 }
1640 }
1641 }
1642
1643 return keep_regs;
1644}
1645
1646static struct ftrace_ops *
1647ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1648static struct ftrace_ops *
1649ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1650static struct ftrace_ops *
1651ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1652
1653static bool skip_record(struct dyn_ftrace *rec)
1654{
1655 /*
1656 * At boot up, weak functions are set to disable. Function tracing
1657 * can be enabled before they are, and they still need to be disabled now.
1658 * If the record is disabled, still continue if it is marked as already
1659 * enabled (this is needed to keep the accounting working).
1660 */
1661 return rec->flags & FTRACE_FL_DISABLED &&
1662 !(rec->flags & FTRACE_FL_ENABLED);
1663}
1664
1665static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1666 int filter_hash,
1667 bool inc)
1668{
1669 struct ftrace_hash *hash;
1670 struct ftrace_hash *other_hash;
1671 struct ftrace_page *pg;
1672 struct dyn_ftrace *rec;
1673 bool update = false;
1674 int count = 0;
1675 int all = false;
1676
1677 /* Only update if the ops has been registered */
1678 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1679 return false;
1680
1681 /*
1682 * In the filter_hash case:
1683 * If the count is zero, we update all records.
1684 * Otherwise we just update the items in the hash.
1685 *
1686 * In the notrace_hash case:
1687 * We enable the update in the hash.
1688 * As disabling notrace means enabling the tracing,
1689 * and enabling notrace means disabling, the inc variable
1690 * gets inversed.
1691 */
1692 if (filter_hash) {
1693 hash = ops->func_hash->filter_hash;
1694 other_hash = ops->func_hash->notrace_hash;
1695 if (ftrace_hash_empty(hash))
1696 all = true;
1697 } else {
1698 inc = !inc;
1699 hash = ops->func_hash->notrace_hash;
1700 other_hash = ops->func_hash->filter_hash;
1701 /*
1702 * If the notrace hash has no items,
1703 * then there's nothing to do.
1704 */
1705 if (ftrace_hash_empty(hash))
1706 return false;
1707 }
1708
1709 do_for_each_ftrace_rec(pg, rec) {
1710 int in_other_hash = 0;
1711 int in_hash = 0;
1712 int match = 0;
1713
1714 if (skip_record(rec))
1715 continue;
1716
1717 if (all) {
1718 /*
1719 * Only the filter_hash affects all records.
1720 * Update if the record is not in the notrace hash.
1721 */
1722 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1723 match = 1;
1724 } else {
1725 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1726 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1727
1728 /*
1729 * If filter_hash is set, we want to match all functions
1730 * that are in the hash but not in the other hash.
1731 *
1732 * If filter_hash is not set, then we are decrementing.
1733 * That means we match anything that is in the hash
1734 * and also in the other_hash. That is, we need to turn
1735 * off functions in the other hash because they are disabled
1736 * by this hash.
1737 */
1738 if (filter_hash && in_hash && !in_other_hash)
1739 match = 1;
1740 else if (!filter_hash && in_hash &&
1741 (in_other_hash || ftrace_hash_empty(other_hash)))
1742 match = 1;
1743 }
1744 if (!match)
1745 continue;
1746
1747 if (inc) {
1748 rec->flags++;
1749 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1750 return false;
1751
1752 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1753 rec->flags |= FTRACE_FL_DIRECT;
1754
1755 /*
1756 * If there's only a single callback registered to a
1757 * function, and the ops has a trampoline registered
1758 * for it, then we can call it directly.
1759 */
1760 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1761 rec->flags |= FTRACE_FL_TRAMP;
1762 else
1763 /*
1764 * If we are adding another function callback
1765 * to this function, and the previous had a
1766 * custom trampoline in use, then we need to go
1767 * back to the default trampoline.
1768 */
1769 rec->flags &= ~FTRACE_FL_TRAMP;
1770
1771 /*
1772 * If any ops wants regs saved for this function
1773 * then all ops will get saved regs.
1774 */
1775 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1776 rec->flags |= FTRACE_FL_REGS;
1777 } else {
1778 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1779 return false;
1780 rec->flags--;
1781
1782 /*
1783 * Only the internal direct_ops should have the
1784 * DIRECT flag set. Thus, if it is removing a
1785 * function, then that function should no longer
1786 * be direct.
1787 */
1788 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1789 rec->flags &= ~FTRACE_FL_DIRECT;
1790
1791 /*
1792 * If the rec had REGS enabled and the ops that is
1793 * being removed had REGS set, then see if there is
1794 * still any ops for this record that wants regs.
1795 * If not, we can stop recording them.
1796 */
1797 if (ftrace_rec_count(rec) > 0 &&
1798 rec->flags & FTRACE_FL_REGS &&
1799 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1800 if (!test_rec_ops_needs_regs(rec))
1801 rec->flags &= ~FTRACE_FL_REGS;
1802 }
1803
1804 /*
1805 * The TRAMP needs to be set only if rec count
1806 * is decremented to one, and the ops that is
1807 * left has a trampoline. As TRAMP can only be
1808 * enabled if there is only a single ops attached
1809 * to it.
1810 */
1811 if (ftrace_rec_count(rec) == 1 &&
1812 ftrace_find_tramp_ops_any_other(rec, ops))
1813 rec->flags |= FTRACE_FL_TRAMP;
1814 else
1815 rec->flags &= ~FTRACE_FL_TRAMP;
1816
1817 /*
1818 * flags will be cleared in ftrace_check_record()
1819 * if rec count is zero.
1820 */
1821 }
1822 count++;
1823
1824 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1825 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1826
1827 /* Shortcut, if we handled all records, we are done. */
1828 if (!all && count == hash->count)
1829 return update;
1830 } while_for_each_ftrace_rec();
1831
1832 return update;
1833}
1834
1835static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1836 int filter_hash)
1837{
1838 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1839}
1840
1841static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1842 int filter_hash)
1843{
1844 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1845}
1846
1847static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1848 int filter_hash, int inc)
1849{
1850 struct ftrace_ops *op;
1851
1852 __ftrace_hash_rec_update(ops, filter_hash, inc);
1853
1854 if (ops->func_hash != &global_ops.local_hash)
1855 return;
1856
1857 /*
1858 * If the ops shares the global_ops hash, then we need to update
1859 * all ops that are enabled and use this hash.
1860 */
1861 do_for_each_ftrace_op(op, ftrace_ops_list) {
1862 /* Already done */
1863 if (op == ops)
1864 continue;
1865 if (op->func_hash == &global_ops.local_hash)
1866 __ftrace_hash_rec_update(op, filter_hash, inc);
1867 } while_for_each_ftrace_op(op);
1868}
1869
1870static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1871 int filter_hash)
1872{
1873 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1874}
1875
1876static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1877 int filter_hash)
1878{
1879 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1880}
1881
1882/*
1883 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1884 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1885 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1886 * Note that old_hash and new_hash has below meanings
1887 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1888 * - If the hash is EMPTY_HASH, it hits nothing
1889 * - Anything else hits the recs which match the hash entries.
1890 *
1891 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1892 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1893 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1894 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1895 * the return value to the caller and eventually to the owner of the DIRECT
1896 * ops.
1897 */
1898static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1899 struct ftrace_hash *old_hash,
1900 struct ftrace_hash *new_hash)
1901{
1902 struct ftrace_page *pg;
1903 struct dyn_ftrace *rec, *end = NULL;
1904 int in_old, in_new;
1905 bool is_ipmodify, is_direct;
1906
1907 /* Only update if the ops has been registered */
1908 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1909 return 0;
1910
1911 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1912 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1913
1914 /* neither IPMODIFY nor DIRECT, skip */
1915 if (!is_ipmodify && !is_direct)
1916 return 0;
1917
1918 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1919 return 0;
1920
1921 /*
1922 * Since the IPMODIFY and DIRECT are very address sensitive
1923 * actions, we do not allow ftrace_ops to set all functions to new
1924 * hash.
1925 */
1926 if (!new_hash || !old_hash)
1927 return -EINVAL;
1928
1929 /* Update rec->flags */
1930 do_for_each_ftrace_rec(pg, rec) {
1931
1932 if (rec->flags & FTRACE_FL_DISABLED)
1933 continue;
1934
1935 /* We need to update only differences of filter_hash */
1936 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1937 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1938 if (in_old == in_new)
1939 continue;
1940
1941 if (in_new) {
1942 if (rec->flags & FTRACE_FL_IPMODIFY) {
1943 int ret;
1944
1945 /* Cannot have two ipmodify on same rec */
1946 if (is_ipmodify)
1947 goto rollback;
1948
1949 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1950
1951 /*
1952 * Another ops with IPMODIFY is already
1953 * attached. We are now attaching a direct
1954 * ops. Run SHARE_IPMODIFY_SELF, to check
1955 * whether sharing is supported.
1956 */
1957 if (!ops->ops_func)
1958 return -EBUSY;
1959 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
1960 if (ret)
1961 return ret;
1962 } else if (is_ipmodify) {
1963 rec->flags |= FTRACE_FL_IPMODIFY;
1964 }
1965 } else if (is_ipmodify) {
1966 rec->flags &= ~FTRACE_FL_IPMODIFY;
1967 }
1968 } while_for_each_ftrace_rec();
1969
1970 return 0;
1971
1972rollback:
1973 end = rec;
1974
1975 /* Roll back what we did above */
1976 do_for_each_ftrace_rec(pg, rec) {
1977
1978 if (rec->flags & FTRACE_FL_DISABLED)
1979 continue;
1980
1981 if (rec == end)
1982 goto err_out;
1983
1984 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1985 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1986 if (in_old == in_new)
1987 continue;
1988
1989 if (in_new)
1990 rec->flags &= ~FTRACE_FL_IPMODIFY;
1991 else
1992 rec->flags |= FTRACE_FL_IPMODIFY;
1993 } while_for_each_ftrace_rec();
1994
1995err_out:
1996 return -EBUSY;
1997}
1998
1999static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2000{
2001 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2002
2003 if (ftrace_hash_empty(hash))
2004 hash = NULL;
2005
2006 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2007}
2008
2009/* Disabling always succeeds */
2010static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2011{
2012 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2013
2014 if (ftrace_hash_empty(hash))
2015 hash = NULL;
2016
2017 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2018}
2019
2020static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2021 struct ftrace_hash *new_hash)
2022{
2023 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2024
2025 if (ftrace_hash_empty(old_hash))
2026 old_hash = NULL;
2027
2028 if (ftrace_hash_empty(new_hash))
2029 new_hash = NULL;
2030
2031 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2032}
2033
2034static void print_ip_ins(const char *fmt, const unsigned char *p)
2035{
2036 char ins[MCOUNT_INSN_SIZE];
2037
2038 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2039 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2040 return;
2041 }
2042
2043 printk(KERN_CONT "%s", fmt);
2044 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2045}
2046
2047enum ftrace_bug_type ftrace_bug_type;
2048const void *ftrace_expected;
2049
2050static void print_bug_type(void)
2051{
2052 switch (ftrace_bug_type) {
2053 case FTRACE_BUG_UNKNOWN:
2054 break;
2055 case FTRACE_BUG_INIT:
2056 pr_info("Initializing ftrace call sites\n");
2057 break;
2058 case FTRACE_BUG_NOP:
2059 pr_info("Setting ftrace call site to NOP\n");
2060 break;
2061 case FTRACE_BUG_CALL:
2062 pr_info("Setting ftrace call site to call ftrace function\n");
2063 break;
2064 case FTRACE_BUG_UPDATE:
2065 pr_info("Updating ftrace call site to call a different ftrace function\n");
2066 break;
2067 }
2068}
2069
2070/**
2071 * ftrace_bug - report and shutdown function tracer
2072 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2073 * @rec: The record that failed
2074 *
2075 * The arch code that enables or disables the function tracing
2076 * can call ftrace_bug() when it has detected a problem in
2077 * modifying the code. @failed should be one of either:
2078 * EFAULT - if the problem happens on reading the @ip address
2079 * EINVAL - if what is read at @ip is not what was expected
2080 * EPERM - if the problem happens on writing to the @ip address
2081 */
2082void ftrace_bug(int failed, struct dyn_ftrace *rec)
2083{
2084 unsigned long ip = rec ? rec->ip : 0;
2085
2086 pr_info("------------[ ftrace bug ]------------\n");
2087
2088 switch (failed) {
2089 case -EFAULT:
2090 pr_info("ftrace faulted on modifying ");
2091 print_ip_sym(KERN_INFO, ip);
2092 break;
2093 case -EINVAL:
2094 pr_info("ftrace failed to modify ");
2095 print_ip_sym(KERN_INFO, ip);
2096 print_ip_ins(" actual: ", (unsigned char *)ip);
2097 pr_cont("\n");
2098 if (ftrace_expected) {
2099 print_ip_ins(" expected: ", ftrace_expected);
2100 pr_cont("\n");
2101 }
2102 break;
2103 case -EPERM:
2104 pr_info("ftrace faulted on writing ");
2105 print_ip_sym(KERN_INFO, ip);
2106 break;
2107 default:
2108 pr_info("ftrace faulted on unknown error ");
2109 print_ip_sym(KERN_INFO, ip);
2110 }
2111 print_bug_type();
2112 if (rec) {
2113 struct ftrace_ops *ops = NULL;
2114
2115 pr_info("ftrace record flags: %lx\n", rec->flags);
2116 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2117 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2118 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2119 ops = ftrace_find_tramp_ops_any(rec);
2120 if (ops) {
2121 do {
2122 pr_cont("\ttramp: %pS (%pS)",
2123 (void *)ops->trampoline,
2124 (void *)ops->func);
2125 ops = ftrace_find_tramp_ops_next(rec, ops);
2126 } while (ops);
2127 } else
2128 pr_cont("\ttramp: ERROR!");
2129
2130 }
2131 ip = ftrace_get_addr_curr(rec);
2132 pr_cont("\n expected tramp: %lx\n", ip);
2133 }
2134
2135 FTRACE_WARN_ON_ONCE(1);
2136}
2137
2138static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2139{
2140 unsigned long flag = 0UL;
2141
2142 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2143
2144 if (skip_record(rec))
2145 return FTRACE_UPDATE_IGNORE;
2146
2147 /*
2148 * If we are updating calls:
2149 *
2150 * If the record has a ref count, then we need to enable it
2151 * because someone is using it.
2152 *
2153 * Otherwise we make sure its disabled.
2154 *
2155 * If we are disabling calls, then disable all records that
2156 * are enabled.
2157 */
2158 if (enable && ftrace_rec_count(rec))
2159 flag = FTRACE_FL_ENABLED;
2160
2161 /*
2162 * If enabling and the REGS flag does not match the REGS_EN, or
2163 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2164 * this record. Set flags to fail the compare against ENABLED.
2165 * Same for direct calls.
2166 */
2167 if (flag) {
2168 if (!(rec->flags & FTRACE_FL_REGS) !=
2169 !(rec->flags & FTRACE_FL_REGS_EN))
2170 flag |= FTRACE_FL_REGS;
2171
2172 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2173 !(rec->flags & FTRACE_FL_TRAMP_EN))
2174 flag |= FTRACE_FL_TRAMP;
2175
2176 /*
2177 * Direct calls are special, as count matters.
2178 * We must test the record for direct, if the
2179 * DIRECT and DIRECT_EN do not match, but only
2180 * if the count is 1. That's because, if the
2181 * count is something other than one, we do not
2182 * want the direct enabled (it will be done via the
2183 * direct helper). But if DIRECT_EN is set, and
2184 * the count is not one, we need to clear it.
2185 */
2186 if (ftrace_rec_count(rec) == 1) {
2187 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2188 !(rec->flags & FTRACE_FL_DIRECT_EN))
2189 flag |= FTRACE_FL_DIRECT;
2190 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2191 flag |= FTRACE_FL_DIRECT;
2192 }
2193 }
2194
2195 /* If the state of this record hasn't changed, then do nothing */
2196 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2197 return FTRACE_UPDATE_IGNORE;
2198
2199 if (flag) {
2200 /* Save off if rec is being enabled (for return value) */
2201 flag ^= rec->flags & FTRACE_FL_ENABLED;
2202
2203 if (update) {
2204 rec->flags |= FTRACE_FL_ENABLED;
2205 if (flag & FTRACE_FL_REGS) {
2206 if (rec->flags & FTRACE_FL_REGS)
2207 rec->flags |= FTRACE_FL_REGS_EN;
2208 else
2209 rec->flags &= ~FTRACE_FL_REGS_EN;
2210 }
2211 if (flag & FTRACE_FL_TRAMP) {
2212 if (rec->flags & FTRACE_FL_TRAMP)
2213 rec->flags |= FTRACE_FL_TRAMP_EN;
2214 else
2215 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2216 }
2217
2218 if (flag & FTRACE_FL_DIRECT) {
2219 /*
2220 * If there's only one user (direct_ops helper)
2221 * then we can call the direct function
2222 * directly (no ftrace trampoline).
2223 */
2224 if (ftrace_rec_count(rec) == 1) {
2225 if (rec->flags & FTRACE_FL_DIRECT)
2226 rec->flags |= FTRACE_FL_DIRECT_EN;
2227 else
2228 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2229 } else {
2230 /*
2231 * Can only call directly if there's
2232 * only one callback to the function.
2233 */
2234 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2235 }
2236 }
2237 }
2238
2239 /*
2240 * If this record is being updated from a nop, then
2241 * return UPDATE_MAKE_CALL.
2242 * Otherwise,
2243 * return UPDATE_MODIFY_CALL to tell the caller to convert
2244 * from the save regs, to a non-save regs function or
2245 * vice versa, or from a trampoline call.
2246 */
2247 if (flag & FTRACE_FL_ENABLED) {
2248 ftrace_bug_type = FTRACE_BUG_CALL;
2249 return FTRACE_UPDATE_MAKE_CALL;
2250 }
2251
2252 ftrace_bug_type = FTRACE_BUG_UPDATE;
2253 return FTRACE_UPDATE_MODIFY_CALL;
2254 }
2255
2256 if (update) {
2257 /* If there's no more users, clear all flags */
2258 if (!ftrace_rec_count(rec))
2259 rec->flags &= FTRACE_FL_DISABLED;
2260 else
2261 /*
2262 * Just disable the record, but keep the ops TRAMP
2263 * and REGS states. The _EN flags must be disabled though.
2264 */
2265 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2266 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2267 }
2268
2269 ftrace_bug_type = FTRACE_BUG_NOP;
2270 return FTRACE_UPDATE_MAKE_NOP;
2271}
2272
2273/**
2274 * ftrace_update_record - set a record that now is tracing or not
2275 * @rec: the record to update
2276 * @enable: set to true if the record is tracing, false to force disable
2277 *
2278 * The records that represent all functions that can be traced need
2279 * to be updated when tracing has been enabled.
2280 */
2281int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2282{
2283 return ftrace_check_record(rec, enable, true);
2284}
2285
2286/**
2287 * ftrace_test_record - check if the record has been enabled or not
2288 * @rec: the record to test
2289 * @enable: set to true to check if enabled, false if it is disabled
2290 *
2291 * The arch code may need to test if a record is already set to
2292 * tracing to determine how to modify the function code that it
2293 * represents.
2294 */
2295int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2296{
2297 return ftrace_check_record(rec, enable, false);
2298}
2299
2300static struct ftrace_ops *
2301ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2302{
2303 struct ftrace_ops *op;
2304 unsigned long ip = rec->ip;
2305
2306 do_for_each_ftrace_op(op, ftrace_ops_list) {
2307
2308 if (!op->trampoline)
2309 continue;
2310
2311 if (hash_contains_ip(ip, op->func_hash))
2312 return op;
2313 } while_for_each_ftrace_op(op);
2314
2315 return NULL;
2316}
2317
2318static struct ftrace_ops *
2319ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2320{
2321 struct ftrace_ops *op;
2322 unsigned long ip = rec->ip;
2323
2324 do_for_each_ftrace_op(op, ftrace_ops_list) {
2325
2326 if (op == op_exclude || !op->trampoline)
2327 continue;
2328
2329 if (hash_contains_ip(ip, op->func_hash))
2330 return op;
2331 } while_for_each_ftrace_op(op);
2332
2333 return NULL;
2334}
2335
2336static struct ftrace_ops *
2337ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2338 struct ftrace_ops *op)
2339{
2340 unsigned long ip = rec->ip;
2341
2342 while_for_each_ftrace_op(op) {
2343
2344 if (!op->trampoline)
2345 continue;
2346
2347 if (hash_contains_ip(ip, op->func_hash))
2348 return op;
2349 }
2350
2351 return NULL;
2352}
2353
2354static struct ftrace_ops *
2355ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2356{
2357 struct ftrace_ops *op;
2358 unsigned long ip = rec->ip;
2359
2360 /*
2361 * Need to check removed ops first.
2362 * If they are being removed, and this rec has a tramp,
2363 * and this rec is in the ops list, then it would be the
2364 * one with the tramp.
2365 */
2366 if (removed_ops) {
2367 if (hash_contains_ip(ip, &removed_ops->old_hash))
2368 return removed_ops;
2369 }
2370
2371 /*
2372 * Need to find the current trampoline for a rec.
2373 * Now, a trampoline is only attached to a rec if there
2374 * was a single 'ops' attached to it. But this can be called
2375 * when we are adding another op to the rec or removing the
2376 * current one. Thus, if the op is being added, we can
2377 * ignore it because it hasn't attached itself to the rec
2378 * yet.
2379 *
2380 * If an ops is being modified (hooking to different functions)
2381 * then we don't care about the new functions that are being
2382 * added, just the old ones (that are probably being removed).
2383 *
2384 * If we are adding an ops to a function that already is using
2385 * a trampoline, it needs to be removed (trampolines are only
2386 * for single ops connected), then an ops that is not being
2387 * modified also needs to be checked.
2388 */
2389 do_for_each_ftrace_op(op, ftrace_ops_list) {
2390
2391 if (!op->trampoline)
2392 continue;
2393
2394 /*
2395 * If the ops is being added, it hasn't gotten to
2396 * the point to be removed from this tree yet.
2397 */
2398 if (op->flags & FTRACE_OPS_FL_ADDING)
2399 continue;
2400
2401
2402 /*
2403 * If the ops is being modified and is in the old
2404 * hash, then it is probably being removed from this
2405 * function.
2406 */
2407 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2408 hash_contains_ip(ip, &op->old_hash))
2409 return op;
2410 /*
2411 * If the ops is not being added or modified, and it's
2412 * in its normal filter hash, then this must be the one
2413 * we want!
2414 */
2415 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2416 hash_contains_ip(ip, op->func_hash))
2417 return op;
2418
2419 } while_for_each_ftrace_op(op);
2420
2421 return NULL;
2422}
2423
2424static struct ftrace_ops *
2425ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2426{
2427 struct ftrace_ops *op;
2428 unsigned long ip = rec->ip;
2429
2430 do_for_each_ftrace_op(op, ftrace_ops_list) {
2431 /* pass rec in as regs to have non-NULL val */
2432 if (hash_contains_ip(ip, op->func_hash))
2433 return op;
2434 } while_for_each_ftrace_op(op);
2435
2436 return NULL;
2437}
2438
2439#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2440/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2441static struct ftrace_hash *direct_functions = EMPTY_HASH;
2442static DEFINE_MUTEX(direct_mutex);
2443int ftrace_direct_func_count;
2444
2445/*
2446 * Search the direct_functions hash to see if the given instruction pointer
2447 * has a direct caller attached to it.
2448 */
2449unsigned long ftrace_find_rec_direct(unsigned long ip)
2450{
2451 struct ftrace_func_entry *entry;
2452
2453 entry = __ftrace_lookup_ip(direct_functions, ip);
2454 if (!entry)
2455 return 0;
2456
2457 return entry->direct;
2458}
2459
2460static struct ftrace_func_entry*
2461ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
2462 struct ftrace_hash **free_hash)
2463{
2464 struct ftrace_func_entry *entry;
2465
2466 if (ftrace_hash_empty(direct_functions) ||
2467 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
2468 struct ftrace_hash *new_hash;
2469 int size = ftrace_hash_empty(direct_functions) ? 0 :
2470 direct_functions->count + 1;
2471
2472 if (size < 32)
2473 size = 32;
2474
2475 new_hash = dup_hash(direct_functions, size);
2476 if (!new_hash)
2477 return NULL;
2478
2479 *free_hash = direct_functions;
2480 direct_functions = new_hash;
2481 }
2482
2483 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2484 if (!entry)
2485 return NULL;
2486
2487 entry->ip = ip;
2488 entry->direct = addr;
2489 __add_hash_entry(direct_functions, entry);
2490 return entry;
2491}
2492
2493static void call_direct_funcs(unsigned long ip, unsigned long pip,
2494 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2495{
2496 unsigned long addr;
2497
2498 addr = ftrace_find_rec_direct(ip);
2499 if (!addr)
2500 return;
2501
2502 arch_ftrace_set_direct_caller(fregs, addr);
2503}
2504
2505struct ftrace_ops direct_ops = {
2506 .func = call_direct_funcs,
2507 .flags = FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2508 | FTRACE_OPS_FL_PERMANENT,
2509 /*
2510 * By declaring the main trampoline as this trampoline
2511 * it will never have one allocated for it. Allocated
2512 * trampolines should not call direct functions.
2513 * The direct_ops should only be called by the builtin
2514 * ftrace_regs_caller trampoline.
2515 */
2516 .trampoline = FTRACE_REGS_ADDR,
2517};
2518#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2519
2520/**
2521 * ftrace_get_addr_new - Get the call address to set to
2522 * @rec: The ftrace record descriptor
2523 *
2524 * If the record has the FTRACE_FL_REGS set, that means that it
2525 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2526 * is not set, then it wants to convert to the normal callback.
2527 *
2528 * Returns the address of the trampoline to set to
2529 */
2530unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2531{
2532 struct ftrace_ops *ops;
2533 unsigned long addr;
2534
2535 if ((rec->flags & FTRACE_FL_DIRECT) &&
2536 (ftrace_rec_count(rec) == 1)) {
2537 addr = ftrace_find_rec_direct(rec->ip);
2538 if (addr)
2539 return addr;
2540 WARN_ON_ONCE(1);
2541 }
2542
2543 /* Trampolines take precedence over regs */
2544 if (rec->flags & FTRACE_FL_TRAMP) {
2545 ops = ftrace_find_tramp_ops_new(rec);
2546 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2547 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2548 (void *)rec->ip, (void *)rec->ip, rec->flags);
2549 /* Ftrace is shutting down, return anything */
2550 return (unsigned long)FTRACE_ADDR;
2551 }
2552 return ops->trampoline;
2553 }
2554
2555 if (rec->flags & FTRACE_FL_REGS)
2556 return (unsigned long)FTRACE_REGS_ADDR;
2557 else
2558 return (unsigned long)FTRACE_ADDR;
2559}
2560
2561/**
2562 * ftrace_get_addr_curr - Get the call address that is already there
2563 * @rec: The ftrace record descriptor
2564 *
2565 * The FTRACE_FL_REGS_EN is set when the record already points to
2566 * a function that saves all the regs. Basically the '_EN' version
2567 * represents the current state of the function.
2568 *
2569 * Returns the address of the trampoline that is currently being called
2570 */
2571unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2572{
2573 struct ftrace_ops *ops;
2574 unsigned long addr;
2575
2576 /* Direct calls take precedence over trampolines */
2577 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2578 addr = ftrace_find_rec_direct(rec->ip);
2579 if (addr)
2580 return addr;
2581 WARN_ON_ONCE(1);
2582 }
2583
2584 /* Trampolines take precedence over regs */
2585 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2586 ops = ftrace_find_tramp_ops_curr(rec);
2587 if (FTRACE_WARN_ON(!ops)) {
2588 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2589 (void *)rec->ip, (void *)rec->ip);
2590 /* Ftrace is shutting down, return anything */
2591 return (unsigned long)FTRACE_ADDR;
2592 }
2593 return ops->trampoline;
2594 }
2595
2596 if (rec->flags & FTRACE_FL_REGS_EN)
2597 return (unsigned long)FTRACE_REGS_ADDR;
2598 else
2599 return (unsigned long)FTRACE_ADDR;
2600}
2601
2602static int
2603__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2604{
2605 unsigned long ftrace_old_addr;
2606 unsigned long ftrace_addr;
2607 int ret;
2608
2609 ftrace_addr = ftrace_get_addr_new(rec);
2610
2611 /* This needs to be done before we call ftrace_update_record */
2612 ftrace_old_addr = ftrace_get_addr_curr(rec);
2613
2614 ret = ftrace_update_record(rec, enable);
2615
2616 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2617
2618 switch (ret) {
2619 case FTRACE_UPDATE_IGNORE:
2620 return 0;
2621
2622 case FTRACE_UPDATE_MAKE_CALL:
2623 ftrace_bug_type = FTRACE_BUG_CALL;
2624 return ftrace_make_call(rec, ftrace_addr);
2625
2626 case FTRACE_UPDATE_MAKE_NOP:
2627 ftrace_bug_type = FTRACE_BUG_NOP;
2628 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2629
2630 case FTRACE_UPDATE_MODIFY_CALL:
2631 ftrace_bug_type = FTRACE_BUG_UPDATE;
2632 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2633 }
2634
2635 return -1; /* unknown ftrace bug */
2636}
2637
2638void __weak ftrace_replace_code(int mod_flags)
2639{
2640 struct dyn_ftrace *rec;
2641 struct ftrace_page *pg;
2642 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2643 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2644 int failed;
2645
2646 if (unlikely(ftrace_disabled))
2647 return;
2648
2649 do_for_each_ftrace_rec(pg, rec) {
2650
2651 if (skip_record(rec))
2652 continue;
2653
2654 failed = __ftrace_replace_code(rec, enable);
2655 if (failed) {
2656 ftrace_bug(failed, rec);
2657 /* Stop processing */
2658 return;
2659 }
2660 if (schedulable)
2661 cond_resched();
2662 } while_for_each_ftrace_rec();
2663}
2664
2665struct ftrace_rec_iter {
2666 struct ftrace_page *pg;
2667 int index;
2668};
2669
2670/**
2671 * ftrace_rec_iter_start - start up iterating over traced functions
2672 *
2673 * Returns an iterator handle that is used to iterate over all
2674 * the records that represent address locations where functions
2675 * are traced.
2676 *
2677 * May return NULL if no records are available.
2678 */
2679struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2680{
2681 /*
2682 * We only use a single iterator.
2683 * Protected by the ftrace_lock mutex.
2684 */
2685 static struct ftrace_rec_iter ftrace_rec_iter;
2686 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2687
2688 iter->pg = ftrace_pages_start;
2689 iter->index = 0;
2690
2691 /* Could have empty pages */
2692 while (iter->pg && !iter->pg->index)
2693 iter->pg = iter->pg->next;
2694
2695 if (!iter->pg)
2696 return NULL;
2697
2698 return iter;
2699}
2700
2701/**
2702 * ftrace_rec_iter_next - get the next record to process.
2703 * @iter: The handle to the iterator.
2704 *
2705 * Returns the next iterator after the given iterator @iter.
2706 */
2707struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2708{
2709 iter->index++;
2710
2711 if (iter->index >= iter->pg->index) {
2712 iter->pg = iter->pg->next;
2713 iter->index = 0;
2714
2715 /* Could have empty pages */
2716 while (iter->pg && !iter->pg->index)
2717 iter->pg = iter->pg->next;
2718 }
2719
2720 if (!iter->pg)
2721 return NULL;
2722
2723 return iter;
2724}
2725
2726/**
2727 * ftrace_rec_iter_record - get the record at the iterator location
2728 * @iter: The current iterator location
2729 *
2730 * Returns the record that the current @iter is at.
2731 */
2732struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2733{
2734 return &iter->pg->records[iter->index];
2735}
2736
2737static int
2738ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2739{
2740 int ret;
2741
2742 if (unlikely(ftrace_disabled))
2743 return 0;
2744
2745 ret = ftrace_init_nop(mod, rec);
2746 if (ret) {
2747 ftrace_bug_type = FTRACE_BUG_INIT;
2748 ftrace_bug(ret, rec);
2749 return 0;
2750 }
2751 return 1;
2752}
2753
2754/*
2755 * archs can override this function if they must do something
2756 * before the modifying code is performed.
2757 */
2758void __weak ftrace_arch_code_modify_prepare(void)
2759{
2760}
2761
2762/*
2763 * archs can override this function if they must do something
2764 * after the modifying code is performed.
2765 */
2766void __weak ftrace_arch_code_modify_post_process(void)
2767{
2768}
2769
2770static int update_ftrace_func(ftrace_func_t func)
2771{
2772 static ftrace_func_t save_func;
2773
2774 /* Avoid updating if it hasn't changed */
2775 if (func == save_func)
2776 return 0;
2777
2778 save_func = func;
2779
2780 return ftrace_update_ftrace_func(func);
2781}
2782
2783void ftrace_modify_all_code(int command)
2784{
2785 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2786 int mod_flags = 0;
2787 int err = 0;
2788
2789 if (command & FTRACE_MAY_SLEEP)
2790 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2791
2792 /*
2793 * If the ftrace_caller calls a ftrace_ops func directly,
2794 * we need to make sure that it only traces functions it
2795 * expects to trace. When doing the switch of functions,
2796 * we need to update to the ftrace_ops_list_func first
2797 * before the transition between old and new calls are set,
2798 * as the ftrace_ops_list_func will check the ops hashes
2799 * to make sure the ops are having the right functions
2800 * traced.
2801 */
2802 if (update) {
2803 err = update_ftrace_func(ftrace_ops_list_func);
2804 if (FTRACE_WARN_ON(err))
2805 return;
2806 }
2807
2808 if (command & FTRACE_UPDATE_CALLS)
2809 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2810 else if (command & FTRACE_DISABLE_CALLS)
2811 ftrace_replace_code(mod_flags);
2812
2813 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2814 function_trace_op = set_function_trace_op;
2815 smp_wmb();
2816 /* If irqs are disabled, we are in stop machine */
2817 if (!irqs_disabled())
2818 smp_call_function(ftrace_sync_ipi, NULL, 1);
2819 err = update_ftrace_func(ftrace_trace_function);
2820 if (FTRACE_WARN_ON(err))
2821 return;
2822 }
2823
2824 if (command & FTRACE_START_FUNC_RET)
2825 err = ftrace_enable_ftrace_graph_caller();
2826 else if (command & FTRACE_STOP_FUNC_RET)
2827 err = ftrace_disable_ftrace_graph_caller();
2828 FTRACE_WARN_ON(err);
2829}
2830
2831static int __ftrace_modify_code(void *data)
2832{
2833 int *command = data;
2834
2835 ftrace_modify_all_code(*command);
2836
2837 return 0;
2838}
2839
2840/**
2841 * ftrace_run_stop_machine - go back to the stop machine method
2842 * @command: The command to tell ftrace what to do
2843 *
2844 * If an arch needs to fall back to the stop machine method, the
2845 * it can call this function.
2846 */
2847void ftrace_run_stop_machine(int command)
2848{
2849 stop_machine(__ftrace_modify_code, &command, NULL);
2850}
2851
2852/**
2853 * arch_ftrace_update_code - modify the code to trace or not trace
2854 * @command: The command that needs to be done
2855 *
2856 * Archs can override this function if it does not need to
2857 * run stop_machine() to modify code.
2858 */
2859void __weak arch_ftrace_update_code(int command)
2860{
2861 ftrace_run_stop_machine(command);
2862}
2863
2864static void ftrace_run_update_code(int command)
2865{
2866 ftrace_arch_code_modify_prepare();
2867
2868 /*
2869 * By default we use stop_machine() to modify the code.
2870 * But archs can do what ever they want as long as it
2871 * is safe. The stop_machine() is the safest, but also
2872 * produces the most overhead.
2873 */
2874 arch_ftrace_update_code(command);
2875
2876 ftrace_arch_code_modify_post_process();
2877}
2878
2879static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2880 struct ftrace_ops_hash *old_hash)
2881{
2882 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2883 ops->old_hash.filter_hash = old_hash->filter_hash;
2884 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2885 ftrace_run_update_code(command);
2886 ops->old_hash.filter_hash = NULL;
2887 ops->old_hash.notrace_hash = NULL;
2888 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2889}
2890
2891static ftrace_func_t saved_ftrace_func;
2892static int ftrace_start_up;
2893
2894void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2895{
2896}
2897
2898/* List of trace_ops that have allocated trampolines */
2899static LIST_HEAD(ftrace_ops_trampoline_list);
2900
2901static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2902{
2903 lockdep_assert_held(&ftrace_lock);
2904 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2905}
2906
2907static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2908{
2909 lockdep_assert_held(&ftrace_lock);
2910 list_del_rcu(&ops->list);
2911 synchronize_rcu();
2912}
2913
2914/*
2915 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2916 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2917 * not a module.
2918 */
2919#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2920#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2921
2922static void ftrace_trampoline_free(struct ftrace_ops *ops)
2923{
2924 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2925 ops->trampoline) {
2926 /*
2927 * Record the text poke event before the ksymbol unregister
2928 * event.
2929 */
2930 perf_event_text_poke((void *)ops->trampoline,
2931 (void *)ops->trampoline,
2932 ops->trampoline_size, NULL, 0);
2933 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2934 ops->trampoline, ops->trampoline_size,
2935 true, FTRACE_TRAMPOLINE_SYM);
2936 /* Remove from kallsyms after the perf events */
2937 ftrace_remove_trampoline_from_kallsyms(ops);
2938 }
2939
2940 arch_ftrace_trampoline_free(ops);
2941}
2942
2943static void ftrace_startup_enable(int command)
2944{
2945 if (saved_ftrace_func != ftrace_trace_function) {
2946 saved_ftrace_func = ftrace_trace_function;
2947 command |= FTRACE_UPDATE_TRACE_FUNC;
2948 }
2949
2950 if (!command || !ftrace_enabled)
2951 return;
2952
2953 ftrace_run_update_code(command);
2954}
2955
2956static void ftrace_startup_all(int command)
2957{
2958 update_all_ops = true;
2959 ftrace_startup_enable(command);
2960 update_all_ops = false;
2961}
2962
2963int ftrace_startup(struct ftrace_ops *ops, int command)
2964{
2965 int ret;
2966
2967 if (unlikely(ftrace_disabled))
2968 return -ENODEV;
2969
2970 ret = __register_ftrace_function(ops);
2971 if (ret)
2972 return ret;
2973
2974 ftrace_start_up++;
2975
2976 /*
2977 * Note that ftrace probes uses this to start up
2978 * and modify functions it will probe. But we still
2979 * set the ADDING flag for modification, as probes
2980 * do not have trampolines. If they add them in the
2981 * future, then the probes will need to distinguish
2982 * between adding and updating probes.
2983 */
2984 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2985
2986 ret = ftrace_hash_ipmodify_enable(ops);
2987 if (ret < 0) {
2988 /* Rollback registration process */
2989 __unregister_ftrace_function(ops);
2990 ftrace_start_up--;
2991 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2992 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2993 ftrace_trampoline_free(ops);
2994 return ret;
2995 }
2996
2997 if (ftrace_hash_rec_enable(ops, 1))
2998 command |= FTRACE_UPDATE_CALLS;
2999
3000 ftrace_startup_enable(command);
3001
3002 /*
3003 * If ftrace is in an undefined state, we just remove ops from list
3004 * to prevent the NULL pointer, instead of totally rolling it back and
3005 * free trampoline, because those actions could cause further damage.
3006 */
3007 if (unlikely(ftrace_disabled)) {
3008 __unregister_ftrace_function(ops);
3009 return -ENODEV;
3010 }
3011
3012 ops->flags &= ~FTRACE_OPS_FL_ADDING;
3013
3014 return 0;
3015}
3016
3017int ftrace_shutdown(struct ftrace_ops *ops, int command)
3018{
3019 int ret;
3020
3021 if (unlikely(ftrace_disabled))
3022 return -ENODEV;
3023
3024 ret = __unregister_ftrace_function(ops);
3025 if (ret)
3026 return ret;
3027
3028 ftrace_start_up--;
3029 /*
3030 * Just warn in case of unbalance, no need to kill ftrace, it's not
3031 * critical but the ftrace_call callers may be never nopped again after
3032 * further ftrace uses.
3033 */
3034 WARN_ON_ONCE(ftrace_start_up < 0);
3035
3036 /* Disabling ipmodify never fails */
3037 ftrace_hash_ipmodify_disable(ops);
3038
3039 if (ftrace_hash_rec_disable(ops, 1))
3040 command |= FTRACE_UPDATE_CALLS;
3041
3042 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3043
3044 if (saved_ftrace_func != ftrace_trace_function) {
3045 saved_ftrace_func = ftrace_trace_function;
3046 command |= FTRACE_UPDATE_TRACE_FUNC;
3047 }
3048
3049 if (!command || !ftrace_enabled)
3050 goto out;
3051
3052 /*
3053 * If the ops uses a trampoline, then it needs to be
3054 * tested first on update.
3055 */
3056 ops->flags |= FTRACE_OPS_FL_REMOVING;
3057 removed_ops = ops;
3058
3059 /* The trampoline logic checks the old hashes */
3060 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3061 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3062
3063 ftrace_run_update_code(command);
3064
3065 /*
3066 * If there's no more ops registered with ftrace, run a
3067 * sanity check to make sure all rec flags are cleared.
3068 */
3069 if (rcu_dereference_protected(ftrace_ops_list,
3070 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3071 struct ftrace_page *pg;
3072 struct dyn_ftrace *rec;
3073
3074 do_for_each_ftrace_rec(pg, rec) {
3075 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
3076 pr_warn(" %pS flags:%lx\n",
3077 (void *)rec->ip, rec->flags);
3078 } while_for_each_ftrace_rec();
3079 }
3080
3081 ops->old_hash.filter_hash = NULL;
3082 ops->old_hash.notrace_hash = NULL;
3083
3084 removed_ops = NULL;
3085 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3086
3087out:
3088 /*
3089 * Dynamic ops may be freed, we must make sure that all
3090 * callers are done before leaving this function.
3091 */
3092 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3093 /*
3094 * We need to do a hard force of sched synchronization.
3095 * This is because we use preempt_disable() to do RCU, but
3096 * the function tracers can be called where RCU is not watching
3097 * (like before user_exit()). We can not rely on the RCU
3098 * infrastructure to do the synchronization, thus we must do it
3099 * ourselves.
3100 */
3101 synchronize_rcu_tasks_rude();
3102
3103 /*
3104 * When the kernel is preemptive, tasks can be preempted
3105 * while on a ftrace trampoline. Just scheduling a task on
3106 * a CPU is not good enough to flush them. Calling
3107 * synchronize_rcu_tasks() will wait for those tasks to
3108 * execute and either schedule voluntarily or enter user space.
3109 */
3110 if (IS_ENABLED(CONFIG_PREEMPTION))
3111 synchronize_rcu_tasks();
3112
3113 ftrace_trampoline_free(ops);
3114 }
3115
3116 return 0;
3117}
3118
3119static u64 ftrace_update_time;
3120unsigned long ftrace_update_tot_cnt;
3121unsigned long ftrace_number_of_pages;
3122unsigned long ftrace_number_of_groups;
3123
3124static inline int ops_traces_mod(struct ftrace_ops *ops)
3125{
3126 /*
3127 * Filter_hash being empty will default to trace module.
3128 * But notrace hash requires a test of individual module functions.
3129 */
3130 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3131 ftrace_hash_empty(ops->func_hash->notrace_hash);
3132}
3133
3134static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3135{
3136 bool init_nop = ftrace_need_init_nop();
3137 struct ftrace_page *pg;
3138 struct dyn_ftrace *p;
3139 u64 start, stop;
3140 unsigned long update_cnt = 0;
3141 unsigned long rec_flags = 0;
3142 int i;
3143
3144 start = ftrace_now(raw_smp_processor_id());
3145
3146 /*
3147 * When a module is loaded, this function is called to convert
3148 * the calls to mcount in its text to nops, and also to create
3149 * an entry in the ftrace data. Now, if ftrace is activated
3150 * after this call, but before the module sets its text to
3151 * read-only, the modification of enabling ftrace can fail if
3152 * the read-only is done while ftrace is converting the calls.
3153 * To prevent this, the module's records are set as disabled
3154 * and will be enabled after the call to set the module's text
3155 * to read-only.
3156 */
3157 if (mod)
3158 rec_flags |= FTRACE_FL_DISABLED;
3159
3160 for (pg = new_pgs; pg; pg = pg->next) {
3161
3162 for (i = 0; i < pg->index; i++) {
3163
3164 /* If something went wrong, bail without enabling anything */
3165 if (unlikely(ftrace_disabled))
3166 return -1;
3167
3168 p = &pg->records[i];
3169 p->flags = rec_flags;
3170
3171 /*
3172 * Do the initial record conversion from mcount jump
3173 * to the NOP instructions.
3174 */
3175 if (init_nop && !ftrace_nop_initialize(mod, p))
3176 break;
3177
3178 update_cnt++;
3179 }
3180 }
3181
3182 stop = ftrace_now(raw_smp_processor_id());
3183 ftrace_update_time = stop - start;
3184 ftrace_update_tot_cnt += update_cnt;
3185
3186 return 0;
3187}
3188
3189static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3190{
3191 int order;
3192 int pages;
3193 int cnt;
3194
3195 if (WARN_ON(!count))
3196 return -EINVAL;
3197
3198 /* We want to fill as much as possible, with no empty pages */
3199 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3200 order = fls(pages) - 1;
3201
3202 again:
3203 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3204
3205 if (!pg->records) {
3206 /* if we can't allocate this size, try something smaller */
3207 if (!order)
3208 return -ENOMEM;
3209 order--;
3210 goto again;
3211 }
3212
3213 ftrace_number_of_pages += 1 << order;
3214 ftrace_number_of_groups++;
3215
3216 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3217 pg->order = order;
3218
3219 if (cnt > count)
3220 cnt = count;
3221
3222 return cnt;
3223}
3224
3225static struct ftrace_page *
3226ftrace_allocate_pages(unsigned long num_to_init)
3227{
3228 struct ftrace_page *start_pg;
3229 struct ftrace_page *pg;
3230 int cnt;
3231
3232 if (!num_to_init)
3233 return NULL;
3234
3235 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3236 if (!pg)
3237 return NULL;
3238
3239 /*
3240 * Try to allocate as much as possible in one continues
3241 * location that fills in all of the space. We want to
3242 * waste as little space as possible.
3243 */
3244 for (;;) {
3245 cnt = ftrace_allocate_records(pg, num_to_init);
3246 if (cnt < 0)
3247 goto free_pages;
3248
3249 num_to_init -= cnt;
3250 if (!num_to_init)
3251 break;
3252
3253 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3254 if (!pg->next)
3255 goto free_pages;
3256
3257 pg = pg->next;
3258 }
3259
3260 return start_pg;
3261
3262 free_pages:
3263 pg = start_pg;
3264 while (pg) {
3265 if (pg->records) {
3266 free_pages((unsigned long)pg->records, pg->order);
3267 ftrace_number_of_pages -= 1 << pg->order;
3268 }
3269 start_pg = pg->next;
3270 kfree(pg);
3271 pg = start_pg;
3272 ftrace_number_of_groups--;
3273 }
3274 pr_info("ftrace: FAILED to allocate memory for functions\n");
3275 return NULL;
3276}
3277
3278#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3279
3280struct ftrace_iterator {
3281 loff_t pos;
3282 loff_t func_pos;
3283 loff_t mod_pos;
3284 struct ftrace_page *pg;
3285 struct dyn_ftrace *func;
3286 struct ftrace_func_probe *probe;
3287 struct ftrace_func_entry *probe_entry;
3288 struct trace_parser parser;
3289 struct ftrace_hash *hash;
3290 struct ftrace_ops *ops;
3291 struct trace_array *tr;
3292 struct list_head *mod_list;
3293 int pidx;
3294 int idx;
3295 unsigned flags;
3296};
3297
3298static void *
3299t_probe_next(struct seq_file *m, loff_t *pos)
3300{
3301 struct ftrace_iterator *iter = m->private;
3302 struct trace_array *tr = iter->ops->private;
3303 struct list_head *func_probes;
3304 struct ftrace_hash *hash;
3305 struct list_head *next;
3306 struct hlist_node *hnd = NULL;
3307 struct hlist_head *hhd;
3308 int size;
3309
3310 (*pos)++;
3311 iter->pos = *pos;
3312
3313 if (!tr)
3314 return NULL;
3315
3316 func_probes = &tr->func_probes;
3317 if (list_empty(func_probes))
3318 return NULL;
3319
3320 if (!iter->probe) {
3321 next = func_probes->next;
3322 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3323 }
3324
3325 if (iter->probe_entry)
3326 hnd = &iter->probe_entry->hlist;
3327
3328 hash = iter->probe->ops.func_hash->filter_hash;
3329
3330 /*
3331 * A probe being registered may temporarily have an empty hash
3332 * and it's at the end of the func_probes list.
3333 */
3334 if (!hash || hash == EMPTY_HASH)
3335 return NULL;
3336
3337 size = 1 << hash->size_bits;
3338
3339 retry:
3340 if (iter->pidx >= size) {
3341 if (iter->probe->list.next == func_probes)
3342 return NULL;
3343 next = iter->probe->list.next;
3344 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3345 hash = iter->probe->ops.func_hash->filter_hash;
3346 size = 1 << hash->size_bits;
3347 iter->pidx = 0;
3348 }
3349
3350 hhd = &hash->buckets[iter->pidx];
3351
3352 if (hlist_empty(hhd)) {
3353 iter->pidx++;
3354 hnd = NULL;
3355 goto retry;
3356 }
3357
3358 if (!hnd)
3359 hnd = hhd->first;
3360 else {
3361 hnd = hnd->next;
3362 if (!hnd) {
3363 iter->pidx++;
3364 goto retry;
3365 }
3366 }
3367
3368 if (WARN_ON_ONCE(!hnd))
3369 return NULL;
3370
3371 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3372
3373 return iter;
3374}
3375
3376static void *t_probe_start(struct seq_file *m, loff_t *pos)
3377{
3378 struct ftrace_iterator *iter = m->private;
3379 void *p = NULL;
3380 loff_t l;
3381
3382 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3383 return NULL;
3384
3385 if (iter->mod_pos > *pos)
3386 return NULL;
3387
3388 iter->probe = NULL;
3389 iter->probe_entry = NULL;
3390 iter->pidx = 0;
3391 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3392 p = t_probe_next(m, &l);
3393 if (!p)
3394 break;
3395 }
3396 if (!p)
3397 return NULL;
3398
3399 /* Only set this if we have an item */
3400 iter->flags |= FTRACE_ITER_PROBE;
3401
3402 return iter;
3403}
3404
3405static int
3406t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3407{
3408 struct ftrace_func_entry *probe_entry;
3409 struct ftrace_probe_ops *probe_ops;
3410 struct ftrace_func_probe *probe;
3411
3412 probe = iter->probe;
3413 probe_entry = iter->probe_entry;
3414
3415 if (WARN_ON_ONCE(!probe || !probe_entry))
3416 return -EIO;
3417
3418 probe_ops = probe->probe_ops;
3419
3420 if (probe_ops->print)
3421 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3422
3423 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3424 (void *)probe_ops->func);
3425
3426 return 0;
3427}
3428
3429static void *
3430t_mod_next(struct seq_file *m, loff_t *pos)
3431{
3432 struct ftrace_iterator *iter = m->private;
3433 struct trace_array *tr = iter->tr;
3434
3435 (*pos)++;
3436 iter->pos = *pos;
3437
3438 iter->mod_list = iter->mod_list->next;
3439
3440 if (iter->mod_list == &tr->mod_trace ||
3441 iter->mod_list == &tr->mod_notrace) {
3442 iter->flags &= ~FTRACE_ITER_MOD;
3443 return NULL;
3444 }
3445
3446 iter->mod_pos = *pos;
3447
3448 return iter;
3449}
3450
3451static void *t_mod_start(struct seq_file *m, loff_t *pos)
3452{
3453 struct ftrace_iterator *iter = m->private;
3454 void *p = NULL;
3455 loff_t l;
3456
3457 if (iter->func_pos > *pos)
3458 return NULL;
3459
3460 iter->mod_pos = iter->func_pos;
3461
3462 /* probes are only available if tr is set */
3463 if (!iter->tr)
3464 return NULL;
3465
3466 for (l = 0; l <= (*pos - iter->func_pos); ) {
3467 p = t_mod_next(m, &l);
3468 if (!p)
3469 break;
3470 }
3471 if (!p) {
3472 iter->flags &= ~FTRACE_ITER_MOD;
3473 return t_probe_start(m, pos);
3474 }
3475
3476 /* Only set this if we have an item */
3477 iter->flags |= FTRACE_ITER_MOD;
3478
3479 return iter;
3480}
3481
3482static int
3483t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3484{
3485 struct ftrace_mod_load *ftrace_mod;
3486 struct trace_array *tr = iter->tr;
3487
3488 if (WARN_ON_ONCE(!iter->mod_list) ||
3489 iter->mod_list == &tr->mod_trace ||
3490 iter->mod_list == &tr->mod_notrace)
3491 return -EIO;
3492
3493 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3494
3495 if (ftrace_mod->func)
3496 seq_printf(m, "%s", ftrace_mod->func);
3497 else
3498 seq_putc(m, '*');
3499
3500 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3501
3502 return 0;
3503}
3504
3505static void *
3506t_func_next(struct seq_file *m, loff_t *pos)
3507{
3508 struct ftrace_iterator *iter = m->private;
3509 struct dyn_ftrace *rec = NULL;
3510
3511 (*pos)++;
3512
3513 retry:
3514 if (iter->idx >= iter->pg->index) {
3515 if (iter->pg->next) {
3516 iter->pg = iter->pg->next;
3517 iter->idx = 0;
3518 goto retry;
3519 }
3520 } else {
3521 rec = &iter->pg->records[iter->idx++];
3522 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3523 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3524
3525 ((iter->flags & FTRACE_ITER_ENABLED) &&
3526 !(rec->flags & FTRACE_FL_ENABLED))) {
3527
3528 rec = NULL;
3529 goto retry;
3530 }
3531 }
3532
3533 if (!rec)
3534 return NULL;
3535
3536 iter->pos = iter->func_pos = *pos;
3537 iter->func = rec;
3538
3539 return iter;
3540}
3541
3542static void *
3543t_next(struct seq_file *m, void *v, loff_t *pos)
3544{
3545 struct ftrace_iterator *iter = m->private;
3546 loff_t l = *pos; /* t_probe_start() must use original pos */
3547 void *ret;
3548
3549 if (unlikely(ftrace_disabled))
3550 return NULL;
3551
3552 if (iter->flags & FTRACE_ITER_PROBE)
3553 return t_probe_next(m, pos);
3554
3555 if (iter->flags & FTRACE_ITER_MOD)
3556 return t_mod_next(m, pos);
3557
3558 if (iter->flags & FTRACE_ITER_PRINTALL) {
3559 /* next must increment pos, and t_probe_start does not */
3560 (*pos)++;
3561 return t_mod_start(m, &l);
3562 }
3563
3564 ret = t_func_next(m, pos);
3565
3566 if (!ret)
3567 return t_mod_start(m, &l);
3568
3569 return ret;
3570}
3571
3572static void reset_iter_read(struct ftrace_iterator *iter)
3573{
3574 iter->pos = 0;
3575 iter->func_pos = 0;
3576 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3577}
3578
3579static void *t_start(struct seq_file *m, loff_t *pos)
3580{
3581 struct ftrace_iterator *iter = m->private;
3582 void *p = NULL;
3583 loff_t l;
3584
3585 mutex_lock(&ftrace_lock);
3586
3587 if (unlikely(ftrace_disabled))
3588 return NULL;
3589
3590 /*
3591 * If an lseek was done, then reset and start from beginning.
3592 */
3593 if (*pos < iter->pos)
3594 reset_iter_read(iter);
3595
3596 /*
3597 * For set_ftrace_filter reading, if we have the filter
3598 * off, we can short cut and just print out that all
3599 * functions are enabled.
3600 */
3601 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3602 ftrace_hash_empty(iter->hash)) {
3603 iter->func_pos = 1; /* Account for the message */
3604 if (*pos > 0)
3605 return t_mod_start(m, pos);
3606 iter->flags |= FTRACE_ITER_PRINTALL;
3607 /* reset in case of seek/pread */
3608 iter->flags &= ~FTRACE_ITER_PROBE;
3609 return iter;
3610 }
3611
3612 if (iter->flags & FTRACE_ITER_MOD)
3613 return t_mod_start(m, pos);
3614
3615 /*
3616 * Unfortunately, we need to restart at ftrace_pages_start
3617 * every time we let go of the ftrace_mutex. This is because
3618 * those pointers can change without the lock.
3619 */
3620 iter->pg = ftrace_pages_start;
3621 iter->idx = 0;
3622 for (l = 0; l <= *pos; ) {
3623 p = t_func_next(m, &l);
3624 if (!p)
3625 break;
3626 }
3627
3628 if (!p)
3629 return t_mod_start(m, pos);
3630
3631 return iter;
3632}
3633
3634static void t_stop(struct seq_file *m, void *p)
3635{
3636 mutex_unlock(&ftrace_lock);
3637}
3638
3639void * __weak
3640arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3641{
3642 return NULL;
3643}
3644
3645static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3646 struct dyn_ftrace *rec)
3647{
3648 void *ptr;
3649
3650 ptr = arch_ftrace_trampoline_func(ops, rec);
3651 if (ptr)
3652 seq_printf(m, " ->%pS", ptr);
3653}
3654
3655#ifdef FTRACE_MCOUNT_MAX_OFFSET
3656/*
3657 * Weak functions can still have an mcount/fentry that is saved in
3658 * the __mcount_loc section. These can be detected by having a
3659 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3660 * symbol found by kallsyms is not the function that the mcount/fentry
3661 * is part of. The offset is much greater in these cases.
3662 *
3663 * Test the record to make sure that the ip points to a valid kallsyms
3664 * and if not, mark it disabled.
3665 */
3666static int test_for_valid_rec(struct dyn_ftrace *rec)
3667{
3668 char str[KSYM_SYMBOL_LEN];
3669 unsigned long offset;
3670 const char *ret;
3671
3672 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3673
3674 /* Weak functions can cause invalid addresses */
3675 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3676 rec->flags |= FTRACE_FL_DISABLED;
3677 return 0;
3678 }
3679 return 1;
3680}
3681
3682static struct workqueue_struct *ftrace_check_wq __initdata;
3683static struct work_struct ftrace_check_work __initdata;
3684
3685/*
3686 * Scan all the mcount/fentry entries to make sure they are valid.
3687 */
3688static __init void ftrace_check_work_func(struct work_struct *work)
3689{
3690 struct ftrace_page *pg;
3691 struct dyn_ftrace *rec;
3692
3693 mutex_lock(&ftrace_lock);
3694 do_for_each_ftrace_rec(pg, rec) {
3695 test_for_valid_rec(rec);
3696 } while_for_each_ftrace_rec();
3697 mutex_unlock(&ftrace_lock);
3698}
3699
3700static int __init ftrace_check_for_weak_functions(void)
3701{
3702 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3703
3704 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3705
3706 queue_work(ftrace_check_wq, &ftrace_check_work);
3707 return 0;
3708}
3709
3710static int __init ftrace_check_sync(void)
3711{
3712 /* Make sure the ftrace_check updates are finished */
3713 if (ftrace_check_wq)
3714 destroy_workqueue(ftrace_check_wq);
3715 return 0;
3716}
3717
3718late_initcall_sync(ftrace_check_sync);
3719subsys_initcall(ftrace_check_for_weak_functions);
3720
3721static int print_rec(struct seq_file *m, unsigned long ip)
3722{
3723 unsigned long offset;
3724 char str[KSYM_SYMBOL_LEN];
3725 char *modname;
3726 const char *ret;
3727
3728 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3729 /* Weak functions can cause invalid addresses */
3730 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3731 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3732 FTRACE_INVALID_FUNCTION, offset);
3733 ret = NULL;
3734 }
3735
3736 seq_puts(m, str);
3737 if (modname)
3738 seq_printf(m, " [%s]", modname);
3739 return ret == NULL ? -1 : 0;
3740}
3741#else
3742static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3743{
3744 return 1;
3745}
3746
3747static inline int print_rec(struct seq_file *m, unsigned long ip)
3748{
3749 seq_printf(m, "%ps", (void *)ip);
3750 return 0;
3751}
3752#endif
3753
3754static int t_show(struct seq_file *m, void *v)
3755{
3756 struct ftrace_iterator *iter = m->private;
3757 struct dyn_ftrace *rec;
3758
3759 if (iter->flags & FTRACE_ITER_PROBE)
3760 return t_probe_show(m, iter);
3761
3762 if (iter->flags & FTRACE_ITER_MOD)
3763 return t_mod_show(m, iter);
3764
3765 if (iter->flags & FTRACE_ITER_PRINTALL) {
3766 if (iter->flags & FTRACE_ITER_NOTRACE)
3767 seq_puts(m, "#### no functions disabled ####\n");
3768 else
3769 seq_puts(m, "#### all functions enabled ####\n");
3770 return 0;
3771 }
3772
3773 rec = iter->func;
3774
3775 if (!rec)
3776 return 0;
3777
3778 if (print_rec(m, rec->ip)) {
3779 /* This should only happen when a rec is disabled */
3780 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3781 seq_putc(m, '\n');
3782 return 0;
3783 }
3784
3785 if (iter->flags & FTRACE_ITER_ENABLED) {
3786 struct ftrace_ops *ops;
3787
3788 seq_printf(m, " (%ld)%s%s%s",
3789 ftrace_rec_count(rec),
3790 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3791 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3792 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3793 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3794 ops = ftrace_find_tramp_ops_any(rec);
3795 if (ops) {
3796 do {
3797 seq_printf(m, "\ttramp: %pS (%pS)",
3798 (void *)ops->trampoline,
3799 (void *)ops->func);
3800 add_trampoline_func(m, ops, rec);
3801 ops = ftrace_find_tramp_ops_next(rec, ops);
3802 } while (ops);
3803 } else
3804 seq_puts(m, "\ttramp: ERROR!");
3805 } else {
3806 add_trampoline_func(m, NULL, rec);
3807 }
3808 if (rec->flags & FTRACE_FL_DIRECT) {
3809 unsigned long direct;
3810
3811 direct = ftrace_find_rec_direct(rec->ip);
3812 if (direct)
3813 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3814 }
3815 }
3816
3817 seq_putc(m, '\n');
3818
3819 return 0;
3820}
3821
3822static const struct seq_operations show_ftrace_seq_ops = {
3823 .start = t_start,
3824 .next = t_next,
3825 .stop = t_stop,
3826 .show = t_show,
3827};
3828
3829static int
3830ftrace_avail_open(struct inode *inode, struct file *file)
3831{
3832 struct ftrace_iterator *iter;
3833 int ret;
3834
3835 ret = security_locked_down(LOCKDOWN_TRACEFS);
3836 if (ret)
3837 return ret;
3838
3839 if (unlikely(ftrace_disabled))
3840 return -ENODEV;
3841
3842 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3843 if (!iter)
3844 return -ENOMEM;
3845
3846 iter->pg = ftrace_pages_start;
3847 iter->ops = &global_ops;
3848
3849 return 0;
3850}
3851
3852static int
3853ftrace_enabled_open(struct inode *inode, struct file *file)
3854{
3855 struct ftrace_iterator *iter;
3856
3857 /*
3858 * This shows us what functions are currently being
3859 * traced and by what. Not sure if we want lockdown
3860 * to hide such critical information for an admin.
3861 * Although, perhaps it can show information we don't
3862 * want people to see, but if something is tracing
3863 * something, we probably want to know about it.
3864 */
3865
3866 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3867 if (!iter)
3868 return -ENOMEM;
3869
3870 iter->pg = ftrace_pages_start;
3871 iter->flags = FTRACE_ITER_ENABLED;
3872 iter->ops = &global_ops;
3873
3874 return 0;
3875}
3876
3877/**
3878 * ftrace_regex_open - initialize function tracer filter files
3879 * @ops: The ftrace_ops that hold the hash filters
3880 * @flag: The type of filter to process
3881 * @inode: The inode, usually passed in to your open routine
3882 * @file: The file, usually passed in to your open routine
3883 *
3884 * ftrace_regex_open() initializes the filter files for the
3885 * @ops. Depending on @flag it may process the filter hash or
3886 * the notrace hash of @ops. With this called from the open
3887 * routine, you can use ftrace_filter_write() for the write
3888 * routine if @flag has FTRACE_ITER_FILTER set, or
3889 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3890 * tracing_lseek() should be used as the lseek routine, and
3891 * release must call ftrace_regex_release().
3892 */
3893int
3894ftrace_regex_open(struct ftrace_ops *ops, int flag,
3895 struct inode *inode, struct file *file)
3896{
3897 struct ftrace_iterator *iter;
3898 struct ftrace_hash *hash;
3899 struct list_head *mod_head;
3900 struct trace_array *tr = ops->private;
3901 int ret = -ENOMEM;
3902
3903 ftrace_ops_init(ops);
3904
3905 if (unlikely(ftrace_disabled))
3906 return -ENODEV;
3907
3908 if (tracing_check_open_get_tr(tr))
3909 return -ENODEV;
3910
3911 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3912 if (!iter)
3913 goto out;
3914
3915 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3916 goto out;
3917
3918 iter->ops = ops;
3919 iter->flags = flag;
3920 iter->tr = tr;
3921
3922 mutex_lock(&ops->func_hash->regex_lock);
3923
3924 if (flag & FTRACE_ITER_NOTRACE) {
3925 hash = ops->func_hash->notrace_hash;
3926 mod_head = tr ? &tr->mod_notrace : NULL;
3927 } else {
3928 hash = ops->func_hash->filter_hash;
3929 mod_head = tr ? &tr->mod_trace : NULL;
3930 }
3931
3932 iter->mod_list = mod_head;
3933
3934 if (file->f_mode & FMODE_WRITE) {
3935 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3936
3937 if (file->f_flags & O_TRUNC) {
3938 iter->hash = alloc_ftrace_hash(size_bits);
3939 clear_ftrace_mod_list(mod_head);
3940 } else {
3941 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3942 }
3943
3944 if (!iter->hash) {
3945 trace_parser_put(&iter->parser);
3946 goto out_unlock;
3947 }
3948 } else
3949 iter->hash = hash;
3950
3951 ret = 0;
3952
3953 if (file->f_mode & FMODE_READ) {
3954 iter->pg = ftrace_pages_start;
3955
3956 ret = seq_open(file, &show_ftrace_seq_ops);
3957 if (!ret) {
3958 struct seq_file *m = file->private_data;
3959 m->private = iter;
3960 } else {
3961 /* Failed */
3962 free_ftrace_hash(iter->hash);
3963 trace_parser_put(&iter->parser);
3964 }
3965 } else
3966 file->private_data = iter;
3967
3968 out_unlock:
3969 mutex_unlock(&ops->func_hash->regex_lock);
3970
3971 out:
3972 if (ret) {
3973 kfree(iter);
3974 if (tr)
3975 trace_array_put(tr);
3976 }
3977
3978 return ret;
3979}
3980
3981static int
3982ftrace_filter_open(struct inode *inode, struct file *file)
3983{
3984 struct ftrace_ops *ops = inode->i_private;
3985
3986 /* Checks for tracefs lockdown */
3987 return ftrace_regex_open(ops,
3988 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3989 inode, file);
3990}
3991
3992static int
3993ftrace_notrace_open(struct inode *inode, struct file *file)
3994{
3995 struct ftrace_ops *ops = inode->i_private;
3996
3997 /* Checks for tracefs lockdown */
3998 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3999 inode, file);
4000}
4001
4002/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4003struct ftrace_glob {
4004 char *search;
4005 unsigned len;
4006 int type;
4007};
4008
4009/*
4010 * If symbols in an architecture don't correspond exactly to the user-visible
4011 * name of what they represent, it is possible to define this function to
4012 * perform the necessary adjustments.
4013*/
4014char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4015{
4016 return str;
4017}
4018
4019static int ftrace_match(char *str, struct ftrace_glob *g)
4020{
4021 int matched = 0;
4022 int slen;
4023
4024 str = arch_ftrace_match_adjust(str, g->search);
4025
4026 switch (g->type) {
4027 case MATCH_FULL:
4028 if (strcmp(str, g->search) == 0)
4029 matched = 1;
4030 break;
4031 case MATCH_FRONT_ONLY:
4032 if (strncmp(str, g->search, g->len) == 0)
4033 matched = 1;
4034 break;
4035 case MATCH_MIDDLE_ONLY:
4036 if (strstr(str, g->search))
4037 matched = 1;
4038 break;
4039 case MATCH_END_ONLY:
4040 slen = strlen(str);
4041 if (slen >= g->len &&
4042 memcmp(str + slen - g->len, g->search, g->len) == 0)
4043 matched = 1;
4044 break;
4045 case MATCH_GLOB:
4046 if (glob_match(g->search, str))
4047 matched = 1;
4048 break;
4049 }
4050
4051 return matched;
4052}
4053
4054static int
4055enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4056{
4057 struct ftrace_func_entry *entry;
4058 int ret = 0;
4059
4060 entry = ftrace_lookup_ip(hash, rec->ip);
4061 if (clear_filter) {
4062 /* Do nothing if it doesn't exist */
4063 if (!entry)
4064 return 0;
4065
4066 free_hash_entry(hash, entry);
4067 } else {
4068 /* Do nothing if it exists */
4069 if (entry)
4070 return 0;
4071
4072 ret = add_hash_entry(hash, rec->ip);
4073 }
4074 return ret;
4075}
4076
4077static int
4078add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4079 int clear_filter)
4080{
4081 long index = simple_strtoul(func_g->search, NULL, 0);
4082 struct ftrace_page *pg;
4083 struct dyn_ftrace *rec;
4084
4085 /* The index starts at 1 */
4086 if (--index < 0)
4087 return 0;
4088
4089 do_for_each_ftrace_rec(pg, rec) {
4090 if (pg->index <= index) {
4091 index -= pg->index;
4092 /* this is a double loop, break goes to the next page */
4093 break;
4094 }
4095 rec = &pg->records[index];
4096 enter_record(hash, rec, clear_filter);
4097 return 1;
4098 } while_for_each_ftrace_rec();
4099 return 0;
4100}
4101
4102#ifdef FTRACE_MCOUNT_MAX_OFFSET
4103static int lookup_ip(unsigned long ip, char **modname, char *str)
4104{
4105 unsigned long offset;
4106
4107 kallsyms_lookup(ip, NULL, &offset, modname, str);
4108 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4109 return -1;
4110 return 0;
4111}
4112#else
4113static int lookup_ip(unsigned long ip, char **modname, char *str)
4114{
4115 kallsyms_lookup(ip, NULL, NULL, modname, str);
4116 return 0;
4117}
4118#endif
4119
4120static int
4121ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4122 struct ftrace_glob *mod_g, int exclude_mod)
4123{
4124 char str[KSYM_SYMBOL_LEN];
4125 char *modname;
4126
4127 if (lookup_ip(rec->ip, &modname, str)) {
4128 /* This should only happen when a rec is disabled */
4129 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4130 !(rec->flags & FTRACE_FL_DISABLED));
4131 return 0;
4132 }
4133
4134 if (mod_g) {
4135 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4136
4137 /* blank module name to match all modules */
4138 if (!mod_g->len) {
4139 /* blank module globbing: modname xor exclude_mod */
4140 if (!exclude_mod != !modname)
4141 goto func_match;
4142 return 0;
4143 }
4144
4145 /*
4146 * exclude_mod is set to trace everything but the given
4147 * module. If it is set and the module matches, then
4148 * return 0. If it is not set, and the module doesn't match
4149 * also return 0. Otherwise, check the function to see if
4150 * that matches.
4151 */
4152 if (!mod_matches == !exclude_mod)
4153 return 0;
4154func_match:
4155 /* blank search means to match all funcs in the mod */
4156 if (!func_g->len)
4157 return 1;
4158 }
4159
4160 return ftrace_match(str, func_g);
4161}
4162
4163static int
4164match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4165{
4166 struct ftrace_page *pg;
4167 struct dyn_ftrace *rec;
4168 struct ftrace_glob func_g = { .type = MATCH_FULL };
4169 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4170 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4171 int exclude_mod = 0;
4172 int found = 0;
4173 int ret;
4174 int clear_filter = 0;
4175
4176 if (func) {
4177 func_g.type = filter_parse_regex(func, len, &func_g.search,
4178 &clear_filter);
4179 func_g.len = strlen(func_g.search);
4180 }
4181
4182 if (mod) {
4183 mod_g.type = filter_parse_regex(mod, strlen(mod),
4184 &mod_g.search, &exclude_mod);
4185 mod_g.len = strlen(mod_g.search);
4186 }
4187
4188 mutex_lock(&ftrace_lock);
4189
4190 if (unlikely(ftrace_disabled))
4191 goto out_unlock;
4192
4193 if (func_g.type == MATCH_INDEX) {
4194 found = add_rec_by_index(hash, &func_g, clear_filter);
4195 goto out_unlock;
4196 }
4197
4198 do_for_each_ftrace_rec(pg, rec) {
4199
4200 if (rec->flags & FTRACE_FL_DISABLED)
4201 continue;
4202
4203 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4204 ret = enter_record(hash, rec, clear_filter);
4205 if (ret < 0) {
4206 found = ret;
4207 goto out_unlock;
4208 }
4209 found = 1;
4210 }
4211 cond_resched();
4212 } while_for_each_ftrace_rec();
4213 out_unlock:
4214 mutex_unlock(&ftrace_lock);
4215
4216 return found;
4217}
4218
4219static int
4220ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4221{
4222 return match_records(hash, buff, len, NULL);
4223}
4224
4225static void ftrace_ops_update_code(struct ftrace_ops *ops,
4226 struct ftrace_ops_hash *old_hash)
4227{
4228 struct ftrace_ops *op;
4229
4230 if (!ftrace_enabled)
4231 return;
4232
4233 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4234 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4235 return;
4236 }
4237
4238 /*
4239 * If this is the shared global_ops filter, then we need to
4240 * check if there is another ops that shares it, is enabled.
4241 * If so, we still need to run the modify code.
4242 */
4243 if (ops->func_hash != &global_ops.local_hash)
4244 return;
4245
4246 do_for_each_ftrace_op(op, ftrace_ops_list) {
4247 if (op->func_hash == &global_ops.local_hash &&
4248 op->flags & FTRACE_OPS_FL_ENABLED) {
4249 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4250 /* Only need to do this once */
4251 return;
4252 }
4253 } while_for_each_ftrace_op(op);
4254}
4255
4256static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4257 struct ftrace_hash **orig_hash,
4258 struct ftrace_hash *hash,
4259 int enable)
4260{
4261 struct ftrace_ops_hash old_hash_ops;
4262 struct ftrace_hash *old_hash;
4263 int ret;
4264
4265 old_hash = *orig_hash;
4266 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4267 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4268 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4269 if (!ret) {
4270 ftrace_ops_update_code(ops, &old_hash_ops);
4271 free_ftrace_hash_rcu(old_hash);
4272 }
4273 return ret;
4274}
4275
4276static bool module_exists(const char *module)
4277{
4278 /* All modules have the symbol __this_module */
4279 static const char this_mod[] = "__this_module";
4280 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4281 unsigned long val;
4282 int n;
4283
4284 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4285
4286 if (n > sizeof(modname) - 1)
4287 return false;
4288
4289 val = module_kallsyms_lookup_name(modname);
4290 return val != 0;
4291}
4292
4293static int cache_mod(struct trace_array *tr,
4294 const char *func, char *module, int enable)
4295{
4296 struct ftrace_mod_load *ftrace_mod, *n;
4297 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4298 int ret;
4299
4300 mutex_lock(&ftrace_lock);
4301
4302 /* We do not cache inverse filters */
4303 if (func[0] == '!') {
4304 func++;
4305 ret = -EINVAL;
4306
4307 /* Look to remove this hash */
4308 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4309 if (strcmp(ftrace_mod->module, module) != 0)
4310 continue;
4311
4312 /* no func matches all */
4313 if (strcmp(func, "*") == 0 ||
4314 (ftrace_mod->func &&
4315 strcmp(ftrace_mod->func, func) == 0)) {
4316 ret = 0;
4317 free_ftrace_mod(ftrace_mod);
4318 continue;
4319 }
4320 }
4321 goto out;
4322 }
4323
4324 ret = -EINVAL;
4325 /* We only care about modules that have not been loaded yet */
4326 if (module_exists(module))
4327 goto out;
4328
4329 /* Save this string off, and execute it when the module is loaded */
4330 ret = ftrace_add_mod(tr, func, module, enable);
4331 out:
4332 mutex_unlock(&ftrace_lock);
4333
4334 return ret;
4335}
4336
4337static int
4338ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4339 int reset, int enable);
4340
4341#ifdef CONFIG_MODULES
4342static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4343 char *mod, bool enable)
4344{
4345 struct ftrace_mod_load *ftrace_mod, *n;
4346 struct ftrace_hash **orig_hash, *new_hash;
4347 LIST_HEAD(process_mods);
4348 char *func;
4349
4350 mutex_lock(&ops->func_hash->regex_lock);
4351
4352 if (enable)
4353 orig_hash = &ops->func_hash->filter_hash;
4354 else
4355 orig_hash = &ops->func_hash->notrace_hash;
4356
4357 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4358 *orig_hash);
4359 if (!new_hash)
4360 goto out; /* warn? */
4361
4362 mutex_lock(&ftrace_lock);
4363
4364 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4365
4366 if (strcmp(ftrace_mod->module, mod) != 0)
4367 continue;
4368
4369 if (ftrace_mod->func)
4370 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4371 else
4372 func = kstrdup("*", GFP_KERNEL);
4373
4374 if (!func) /* warn? */
4375 continue;
4376
4377 list_move(&ftrace_mod->list, &process_mods);
4378
4379 /* Use the newly allocated func, as it may be "*" */
4380 kfree(ftrace_mod->func);
4381 ftrace_mod->func = func;
4382 }
4383
4384 mutex_unlock(&ftrace_lock);
4385
4386 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4387
4388 func = ftrace_mod->func;
4389
4390 /* Grabs ftrace_lock, which is why we have this extra step */
4391 match_records(new_hash, func, strlen(func), mod);
4392 free_ftrace_mod(ftrace_mod);
4393 }
4394
4395 if (enable && list_empty(head))
4396 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4397
4398 mutex_lock(&ftrace_lock);
4399
4400 ftrace_hash_move_and_update_ops(ops, orig_hash,
4401 new_hash, enable);
4402 mutex_unlock(&ftrace_lock);
4403
4404 out:
4405 mutex_unlock(&ops->func_hash->regex_lock);
4406
4407 free_ftrace_hash(new_hash);
4408}
4409
4410static void process_cached_mods(const char *mod_name)
4411{
4412 struct trace_array *tr;
4413 char *mod;
4414
4415 mod = kstrdup(mod_name, GFP_KERNEL);
4416 if (!mod)
4417 return;
4418
4419 mutex_lock(&trace_types_lock);
4420 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4421 if (!list_empty(&tr->mod_trace))
4422 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4423 if (!list_empty(&tr->mod_notrace))
4424 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4425 }
4426 mutex_unlock(&trace_types_lock);
4427
4428 kfree(mod);
4429}
4430#endif
4431
4432/*
4433 * We register the module command as a template to show others how
4434 * to register the a command as well.
4435 */
4436
4437static int
4438ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4439 char *func_orig, char *cmd, char *module, int enable)
4440{
4441 char *func;
4442 int ret;
4443
4444 /* match_records() modifies func, and we need the original */
4445 func = kstrdup(func_orig, GFP_KERNEL);
4446 if (!func)
4447 return -ENOMEM;
4448
4449 /*
4450 * cmd == 'mod' because we only registered this func
4451 * for the 'mod' ftrace_func_command.
4452 * But if you register one func with multiple commands,
4453 * you can tell which command was used by the cmd
4454 * parameter.
4455 */
4456 ret = match_records(hash, func, strlen(func), module);
4457 kfree(func);
4458
4459 if (!ret)
4460 return cache_mod(tr, func_orig, module, enable);
4461 if (ret < 0)
4462 return ret;
4463 return 0;
4464}
4465
4466static struct ftrace_func_command ftrace_mod_cmd = {
4467 .name = "mod",
4468 .func = ftrace_mod_callback,
4469};
4470
4471static int __init ftrace_mod_cmd_init(void)
4472{
4473 return register_ftrace_command(&ftrace_mod_cmd);
4474}
4475core_initcall(ftrace_mod_cmd_init);
4476
4477static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4478 struct ftrace_ops *op, struct ftrace_regs *fregs)
4479{
4480 struct ftrace_probe_ops *probe_ops;
4481 struct ftrace_func_probe *probe;
4482
4483 probe = container_of(op, struct ftrace_func_probe, ops);
4484 probe_ops = probe->probe_ops;
4485
4486 /*
4487 * Disable preemption for these calls to prevent a RCU grace
4488 * period. This syncs the hash iteration and freeing of items
4489 * on the hash. rcu_read_lock is too dangerous here.
4490 */
4491 preempt_disable_notrace();
4492 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4493 preempt_enable_notrace();
4494}
4495
4496struct ftrace_func_map {
4497 struct ftrace_func_entry entry;
4498 void *data;
4499};
4500
4501struct ftrace_func_mapper {
4502 struct ftrace_hash hash;
4503};
4504
4505/**
4506 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4507 *
4508 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4509 */
4510struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4511{
4512 struct ftrace_hash *hash;
4513
4514 /*
4515 * The mapper is simply a ftrace_hash, but since the entries
4516 * in the hash are not ftrace_func_entry type, we define it
4517 * as a separate structure.
4518 */
4519 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4520 return (struct ftrace_func_mapper *)hash;
4521}
4522
4523/**
4524 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4525 * @mapper: The mapper that has the ip maps
4526 * @ip: the instruction pointer to find the data for
4527 *
4528 * Returns the data mapped to @ip if found otherwise NULL. The return
4529 * is actually the address of the mapper data pointer. The address is
4530 * returned for use cases where the data is no bigger than a long, and
4531 * the user can use the data pointer as its data instead of having to
4532 * allocate more memory for the reference.
4533 */
4534void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4535 unsigned long ip)
4536{
4537 struct ftrace_func_entry *entry;
4538 struct ftrace_func_map *map;
4539
4540 entry = ftrace_lookup_ip(&mapper->hash, ip);
4541 if (!entry)
4542 return NULL;
4543
4544 map = (struct ftrace_func_map *)entry;
4545 return &map->data;
4546}
4547
4548/**
4549 * ftrace_func_mapper_add_ip - Map some data to an ip
4550 * @mapper: The mapper that has the ip maps
4551 * @ip: The instruction pointer address to map @data to
4552 * @data: The data to map to @ip
4553 *
4554 * Returns 0 on success otherwise an error.
4555 */
4556int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4557 unsigned long ip, void *data)
4558{
4559 struct ftrace_func_entry *entry;
4560 struct ftrace_func_map *map;
4561
4562 entry = ftrace_lookup_ip(&mapper->hash, ip);
4563 if (entry)
4564 return -EBUSY;
4565
4566 map = kmalloc(sizeof(*map), GFP_KERNEL);
4567 if (!map)
4568 return -ENOMEM;
4569
4570 map->entry.ip = ip;
4571 map->data = data;
4572
4573 __add_hash_entry(&mapper->hash, &map->entry);
4574
4575 return 0;
4576}
4577
4578/**
4579 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4580 * @mapper: The mapper that has the ip maps
4581 * @ip: The instruction pointer address to remove the data from
4582 *
4583 * Returns the data if it is found, otherwise NULL.
4584 * Note, if the data pointer is used as the data itself, (see
4585 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4586 * if the data pointer was set to zero.
4587 */
4588void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4589 unsigned long ip)
4590{
4591 struct ftrace_func_entry *entry;
4592 struct ftrace_func_map *map;
4593 void *data;
4594
4595 entry = ftrace_lookup_ip(&mapper->hash, ip);
4596 if (!entry)
4597 return NULL;
4598
4599 map = (struct ftrace_func_map *)entry;
4600 data = map->data;
4601
4602 remove_hash_entry(&mapper->hash, entry);
4603 kfree(entry);
4604
4605 return data;
4606}
4607
4608/**
4609 * free_ftrace_func_mapper - free a mapping of ips and data
4610 * @mapper: The mapper that has the ip maps
4611 * @free_func: A function to be called on each data item.
4612 *
4613 * This is used to free the function mapper. The @free_func is optional
4614 * and can be used if the data needs to be freed as well.
4615 */
4616void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4617 ftrace_mapper_func free_func)
4618{
4619 struct ftrace_func_entry *entry;
4620 struct ftrace_func_map *map;
4621 struct hlist_head *hhd;
4622 int size, i;
4623
4624 if (!mapper)
4625 return;
4626
4627 if (free_func && mapper->hash.count) {
4628 size = 1 << mapper->hash.size_bits;
4629 for (i = 0; i < size; i++) {
4630 hhd = &mapper->hash.buckets[i];
4631 hlist_for_each_entry(entry, hhd, hlist) {
4632 map = (struct ftrace_func_map *)entry;
4633 free_func(map);
4634 }
4635 }
4636 }
4637 free_ftrace_hash(&mapper->hash);
4638}
4639
4640static void release_probe(struct ftrace_func_probe *probe)
4641{
4642 struct ftrace_probe_ops *probe_ops;
4643
4644 mutex_lock(&ftrace_lock);
4645
4646 WARN_ON(probe->ref <= 0);
4647
4648 /* Subtract the ref that was used to protect this instance */
4649 probe->ref--;
4650
4651 if (!probe->ref) {
4652 probe_ops = probe->probe_ops;
4653 /*
4654 * Sending zero as ip tells probe_ops to free
4655 * the probe->data itself
4656 */
4657 if (probe_ops->free)
4658 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4659 list_del(&probe->list);
4660 kfree(probe);
4661 }
4662 mutex_unlock(&ftrace_lock);
4663}
4664
4665static void acquire_probe_locked(struct ftrace_func_probe *probe)
4666{
4667 /*
4668 * Add one ref to keep it from being freed when releasing the
4669 * ftrace_lock mutex.
4670 */
4671 probe->ref++;
4672}
4673
4674int
4675register_ftrace_function_probe(char *glob, struct trace_array *tr,
4676 struct ftrace_probe_ops *probe_ops,
4677 void *data)
4678{
4679 struct ftrace_func_probe *probe = NULL, *iter;
4680 struct ftrace_func_entry *entry;
4681 struct ftrace_hash **orig_hash;
4682 struct ftrace_hash *old_hash;
4683 struct ftrace_hash *hash;
4684 int count = 0;
4685 int size;
4686 int ret;
4687 int i;
4688
4689 if (WARN_ON(!tr))
4690 return -EINVAL;
4691
4692 /* We do not support '!' for function probes */
4693 if (WARN_ON(glob[0] == '!'))
4694 return -EINVAL;
4695
4696
4697 mutex_lock(&ftrace_lock);
4698 /* Check if the probe_ops is already registered */
4699 list_for_each_entry(iter, &tr->func_probes, list) {
4700 if (iter->probe_ops == probe_ops) {
4701 probe = iter;
4702 break;
4703 }
4704 }
4705 if (!probe) {
4706 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4707 if (!probe) {
4708 mutex_unlock(&ftrace_lock);
4709 return -ENOMEM;
4710 }
4711 probe->probe_ops = probe_ops;
4712 probe->ops.func = function_trace_probe_call;
4713 probe->tr = tr;
4714 ftrace_ops_init(&probe->ops);
4715 list_add(&probe->list, &tr->func_probes);
4716 }
4717
4718 acquire_probe_locked(probe);
4719
4720 mutex_unlock(&ftrace_lock);
4721
4722 /*
4723 * Note, there's a small window here that the func_hash->filter_hash
4724 * may be NULL or empty. Need to be careful when reading the loop.
4725 */
4726 mutex_lock(&probe->ops.func_hash->regex_lock);
4727
4728 orig_hash = &probe->ops.func_hash->filter_hash;
4729 old_hash = *orig_hash;
4730 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4731
4732 if (!hash) {
4733 ret = -ENOMEM;
4734 goto out;
4735 }
4736
4737 ret = ftrace_match_records(hash, glob, strlen(glob));
4738
4739 /* Nothing found? */
4740 if (!ret)
4741 ret = -EINVAL;
4742
4743 if (ret < 0)
4744 goto out;
4745
4746 size = 1 << hash->size_bits;
4747 for (i = 0; i < size; i++) {
4748 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4749 if (ftrace_lookup_ip(old_hash, entry->ip))
4750 continue;
4751 /*
4752 * The caller might want to do something special
4753 * for each function we find. We call the callback
4754 * to give the caller an opportunity to do so.
4755 */
4756 if (probe_ops->init) {
4757 ret = probe_ops->init(probe_ops, tr,
4758 entry->ip, data,
4759 &probe->data);
4760 if (ret < 0) {
4761 if (probe_ops->free && count)
4762 probe_ops->free(probe_ops, tr,
4763 0, probe->data);
4764 probe->data = NULL;
4765 goto out;
4766 }
4767 }
4768 count++;
4769 }
4770 }
4771
4772 mutex_lock(&ftrace_lock);
4773
4774 if (!count) {
4775 /* Nothing was added? */
4776 ret = -EINVAL;
4777 goto out_unlock;
4778 }
4779
4780 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4781 hash, 1);
4782 if (ret < 0)
4783 goto err_unlock;
4784
4785 /* One ref for each new function traced */
4786 probe->ref += count;
4787
4788 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4789 ret = ftrace_startup(&probe->ops, 0);
4790
4791 out_unlock:
4792 mutex_unlock(&ftrace_lock);
4793
4794 if (!ret)
4795 ret = count;
4796 out:
4797 mutex_unlock(&probe->ops.func_hash->regex_lock);
4798 free_ftrace_hash(hash);
4799
4800 release_probe(probe);
4801
4802 return ret;
4803
4804 err_unlock:
4805 if (!probe_ops->free || !count)
4806 goto out_unlock;
4807
4808 /* Failed to do the move, need to call the free functions */
4809 for (i = 0; i < size; i++) {
4810 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4811 if (ftrace_lookup_ip(old_hash, entry->ip))
4812 continue;
4813 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4814 }
4815 }
4816 goto out_unlock;
4817}
4818
4819int
4820unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4821 struct ftrace_probe_ops *probe_ops)
4822{
4823 struct ftrace_func_probe *probe = NULL, *iter;
4824 struct ftrace_ops_hash old_hash_ops;
4825 struct ftrace_func_entry *entry;
4826 struct ftrace_glob func_g;
4827 struct ftrace_hash **orig_hash;
4828 struct ftrace_hash *old_hash;
4829 struct ftrace_hash *hash = NULL;
4830 struct hlist_node *tmp;
4831 struct hlist_head hhd;
4832 char str[KSYM_SYMBOL_LEN];
4833 int count = 0;
4834 int i, ret = -ENODEV;
4835 int size;
4836
4837 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4838 func_g.search = NULL;
4839 else {
4840 int not;
4841
4842 func_g.type = filter_parse_regex(glob, strlen(glob),
4843 &func_g.search, ¬);
4844 func_g.len = strlen(func_g.search);
4845
4846 /* we do not support '!' for function probes */
4847 if (WARN_ON(not))
4848 return -EINVAL;
4849 }
4850
4851 mutex_lock(&ftrace_lock);
4852 /* Check if the probe_ops is already registered */
4853 list_for_each_entry(iter, &tr->func_probes, list) {
4854 if (iter->probe_ops == probe_ops) {
4855 probe = iter;
4856 break;
4857 }
4858 }
4859 if (!probe)
4860 goto err_unlock_ftrace;
4861
4862 ret = -EINVAL;
4863 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4864 goto err_unlock_ftrace;
4865
4866 acquire_probe_locked(probe);
4867
4868 mutex_unlock(&ftrace_lock);
4869
4870 mutex_lock(&probe->ops.func_hash->regex_lock);
4871
4872 orig_hash = &probe->ops.func_hash->filter_hash;
4873 old_hash = *orig_hash;
4874
4875 if (ftrace_hash_empty(old_hash))
4876 goto out_unlock;
4877
4878 old_hash_ops.filter_hash = old_hash;
4879 /* Probes only have filters */
4880 old_hash_ops.notrace_hash = NULL;
4881
4882 ret = -ENOMEM;
4883 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4884 if (!hash)
4885 goto out_unlock;
4886
4887 INIT_HLIST_HEAD(&hhd);
4888
4889 size = 1 << hash->size_bits;
4890 for (i = 0; i < size; i++) {
4891 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4892
4893 if (func_g.search) {
4894 kallsyms_lookup(entry->ip, NULL, NULL,
4895 NULL, str);
4896 if (!ftrace_match(str, &func_g))
4897 continue;
4898 }
4899 count++;
4900 remove_hash_entry(hash, entry);
4901 hlist_add_head(&entry->hlist, &hhd);
4902 }
4903 }
4904
4905 /* Nothing found? */
4906 if (!count) {
4907 ret = -EINVAL;
4908 goto out_unlock;
4909 }
4910
4911 mutex_lock(&ftrace_lock);
4912
4913 WARN_ON(probe->ref < count);
4914
4915 probe->ref -= count;
4916
4917 if (ftrace_hash_empty(hash))
4918 ftrace_shutdown(&probe->ops, 0);
4919
4920 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4921 hash, 1);
4922
4923 /* still need to update the function call sites */
4924 if (ftrace_enabled && !ftrace_hash_empty(hash))
4925 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4926 &old_hash_ops);
4927 synchronize_rcu();
4928
4929 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4930 hlist_del(&entry->hlist);
4931 if (probe_ops->free)
4932 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4933 kfree(entry);
4934 }
4935 mutex_unlock(&ftrace_lock);
4936
4937 out_unlock:
4938 mutex_unlock(&probe->ops.func_hash->regex_lock);
4939 free_ftrace_hash(hash);
4940
4941 release_probe(probe);
4942
4943 return ret;
4944
4945 err_unlock_ftrace:
4946 mutex_unlock(&ftrace_lock);
4947 return ret;
4948}
4949
4950void clear_ftrace_function_probes(struct trace_array *tr)
4951{
4952 struct ftrace_func_probe *probe, *n;
4953
4954 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4955 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4956}
4957
4958static LIST_HEAD(ftrace_commands);
4959static DEFINE_MUTEX(ftrace_cmd_mutex);
4960
4961/*
4962 * Currently we only register ftrace commands from __init, so mark this
4963 * __init too.
4964 */
4965__init int register_ftrace_command(struct ftrace_func_command *cmd)
4966{
4967 struct ftrace_func_command *p;
4968 int ret = 0;
4969
4970 mutex_lock(&ftrace_cmd_mutex);
4971 list_for_each_entry(p, &ftrace_commands, list) {
4972 if (strcmp(cmd->name, p->name) == 0) {
4973 ret = -EBUSY;
4974 goto out_unlock;
4975 }
4976 }
4977 list_add(&cmd->list, &ftrace_commands);
4978 out_unlock:
4979 mutex_unlock(&ftrace_cmd_mutex);
4980
4981 return ret;
4982}
4983
4984/*
4985 * Currently we only unregister ftrace commands from __init, so mark
4986 * this __init too.
4987 */
4988__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4989{
4990 struct ftrace_func_command *p, *n;
4991 int ret = -ENODEV;
4992
4993 mutex_lock(&ftrace_cmd_mutex);
4994 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4995 if (strcmp(cmd->name, p->name) == 0) {
4996 ret = 0;
4997 list_del_init(&p->list);
4998 goto out_unlock;
4999 }
5000 }
5001 out_unlock:
5002 mutex_unlock(&ftrace_cmd_mutex);
5003
5004 return ret;
5005}
5006
5007static int ftrace_process_regex(struct ftrace_iterator *iter,
5008 char *buff, int len, int enable)
5009{
5010 struct ftrace_hash *hash = iter->hash;
5011 struct trace_array *tr = iter->ops->private;
5012 char *func, *command, *next = buff;
5013 struct ftrace_func_command *p;
5014 int ret = -EINVAL;
5015
5016 func = strsep(&next, ":");
5017
5018 if (!next) {
5019 ret = ftrace_match_records(hash, func, len);
5020 if (!ret)
5021 ret = -EINVAL;
5022 if (ret < 0)
5023 return ret;
5024 return 0;
5025 }
5026
5027 /* command found */
5028
5029 command = strsep(&next, ":");
5030
5031 mutex_lock(&ftrace_cmd_mutex);
5032 list_for_each_entry(p, &ftrace_commands, list) {
5033 if (strcmp(p->name, command) == 0) {
5034 ret = p->func(tr, hash, func, command, next, enable);
5035 goto out_unlock;
5036 }
5037 }
5038 out_unlock:
5039 mutex_unlock(&ftrace_cmd_mutex);
5040
5041 return ret;
5042}
5043
5044static ssize_t
5045ftrace_regex_write(struct file *file, const char __user *ubuf,
5046 size_t cnt, loff_t *ppos, int enable)
5047{
5048 struct ftrace_iterator *iter;
5049 struct trace_parser *parser;
5050 ssize_t ret, read;
5051
5052 if (!cnt)
5053 return 0;
5054
5055 if (file->f_mode & FMODE_READ) {
5056 struct seq_file *m = file->private_data;
5057 iter = m->private;
5058 } else
5059 iter = file->private_data;
5060
5061 if (unlikely(ftrace_disabled))
5062 return -ENODEV;
5063
5064 /* iter->hash is a local copy, so we don't need regex_lock */
5065
5066 parser = &iter->parser;
5067 read = trace_get_user(parser, ubuf, cnt, ppos);
5068
5069 if (read >= 0 && trace_parser_loaded(parser) &&
5070 !trace_parser_cont(parser)) {
5071 ret = ftrace_process_regex(iter, parser->buffer,
5072 parser->idx, enable);
5073 trace_parser_clear(parser);
5074 if (ret < 0)
5075 goto out;
5076 }
5077
5078 ret = read;
5079 out:
5080 return ret;
5081}
5082
5083ssize_t
5084ftrace_filter_write(struct file *file, const char __user *ubuf,
5085 size_t cnt, loff_t *ppos)
5086{
5087 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5088}
5089
5090ssize_t
5091ftrace_notrace_write(struct file *file, const char __user *ubuf,
5092 size_t cnt, loff_t *ppos)
5093{
5094 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5095}
5096
5097static int
5098__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5099{
5100 struct ftrace_func_entry *entry;
5101
5102 ip = ftrace_location(ip);
5103 if (!ip)
5104 return -EINVAL;
5105
5106 if (remove) {
5107 entry = ftrace_lookup_ip(hash, ip);
5108 if (!entry)
5109 return -ENOENT;
5110 free_hash_entry(hash, entry);
5111 return 0;
5112 }
5113
5114 return add_hash_entry(hash, ip);
5115}
5116
5117static int
5118ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5119 unsigned int cnt, int remove)
5120{
5121 unsigned int i;
5122 int err;
5123
5124 for (i = 0; i < cnt; i++) {
5125 err = __ftrace_match_addr(hash, ips[i], remove);
5126 if (err) {
5127 /*
5128 * This expects the @hash is a temporary hash and if this
5129 * fails the caller must free the @hash.
5130 */
5131 return err;
5132 }
5133 }
5134 return 0;
5135}
5136
5137static int
5138ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5139 unsigned long *ips, unsigned int cnt,
5140 int remove, int reset, int enable)
5141{
5142 struct ftrace_hash **orig_hash;
5143 struct ftrace_hash *hash;
5144 int ret;
5145
5146 if (unlikely(ftrace_disabled))
5147 return -ENODEV;
5148
5149 mutex_lock(&ops->func_hash->regex_lock);
5150
5151 if (enable)
5152 orig_hash = &ops->func_hash->filter_hash;
5153 else
5154 orig_hash = &ops->func_hash->notrace_hash;
5155
5156 if (reset)
5157 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5158 else
5159 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5160
5161 if (!hash) {
5162 ret = -ENOMEM;
5163 goto out_regex_unlock;
5164 }
5165
5166 if (buf && !ftrace_match_records(hash, buf, len)) {
5167 ret = -EINVAL;
5168 goto out_regex_unlock;
5169 }
5170 if (ips) {
5171 ret = ftrace_match_addr(hash, ips, cnt, remove);
5172 if (ret < 0)
5173 goto out_regex_unlock;
5174 }
5175
5176 mutex_lock(&ftrace_lock);
5177 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5178 mutex_unlock(&ftrace_lock);
5179
5180 out_regex_unlock:
5181 mutex_unlock(&ops->func_hash->regex_lock);
5182
5183 free_ftrace_hash(hash);
5184 return ret;
5185}
5186
5187static int
5188ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5189 int remove, int reset, int enable)
5190{
5191 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5192}
5193
5194#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5195
5196struct ftrace_direct_func {
5197 struct list_head next;
5198 unsigned long addr;
5199 int count;
5200};
5201
5202static LIST_HEAD(ftrace_direct_funcs);
5203
5204/**
5205 * ftrace_find_direct_func - test an address if it is a registered direct caller
5206 * @addr: The address of a registered direct caller
5207 *
5208 * This searches to see if a ftrace direct caller has been registered
5209 * at a specific address, and if so, it returns a descriptor for it.
5210 *
5211 * This can be used by architecture code to see if an address is
5212 * a direct caller (trampoline) attached to a fentry/mcount location.
5213 * This is useful for the function_graph tracer, as it may need to
5214 * do adjustments if it traced a location that also has a direct
5215 * trampoline attached to it.
5216 */
5217struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5218{
5219 struct ftrace_direct_func *entry;
5220 bool found = false;
5221
5222 /* May be called by fgraph trampoline (protected by rcu tasks) */
5223 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5224 if (entry->addr == addr) {
5225 found = true;
5226 break;
5227 }
5228 }
5229 if (found)
5230 return entry;
5231
5232 return NULL;
5233}
5234
5235static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5236{
5237 struct ftrace_direct_func *direct;
5238
5239 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5240 if (!direct)
5241 return NULL;
5242 direct->addr = addr;
5243 direct->count = 0;
5244 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5245 ftrace_direct_func_count++;
5246 return direct;
5247}
5248
5249static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5250
5251/**
5252 * register_ftrace_direct - Call a custom trampoline directly
5253 * @ip: The address of the nop at the beginning of a function
5254 * @addr: The address of the trampoline to call at @ip
5255 *
5256 * This is used to connect a direct call from the nop location (@ip)
5257 * at the start of ftrace traced functions. The location that it calls
5258 * (@addr) must be able to handle a direct call, and save the parameters
5259 * of the function being traced, and restore them (or inject new ones
5260 * if needed), before returning.
5261 *
5262 * Returns:
5263 * 0 on success
5264 * -EBUSY - Another direct function is already attached (there can be only one)
5265 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5266 * -ENOMEM - There was an allocation failure.
5267 */
5268int register_ftrace_direct(unsigned long ip, unsigned long addr)
5269{
5270 struct ftrace_direct_func *direct;
5271 struct ftrace_func_entry *entry;
5272 struct ftrace_hash *free_hash = NULL;
5273 struct dyn_ftrace *rec;
5274 int ret = -ENODEV;
5275
5276 mutex_lock(&direct_mutex);
5277
5278 ip = ftrace_location(ip);
5279 if (!ip)
5280 goto out_unlock;
5281
5282 /* See if there's a direct function at @ip already */
5283 ret = -EBUSY;
5284 if (ftrace_find_rec_direct(ip))
5285 goto out_unlock;
5286
5287 ret = -ENODEV;
5288 rec = lookup_rec(ip, ip);
5289 if (!rec)
5290 goto out_unlock;
5291
5292 /*
5293 * Check if the rec says it has a direct call but we didn't
5294 * find one earlier?
5295 */
5296 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5297 goto out_unlock;
5298
5299 /* Make sure the ip points to the exact record */
5300 if (ip != rec->ip) {
5301 ip = rec->ip;
5302 /* Need to check this ip for a direct. */
5303 if (ftrace_find_rec_direct(ip))
5304 goto out_unlock;
5305 }
5306
5307 ret = -ENOMEM;
5308 direct = ftrace_find_direct_func(addr);
5309 if (!direct) {
5310 direct = ftrace_alloc_direct_func(addr);
5311 if (!direct)
5312 goto out_unlock;
5313 }
5314
5315 entry = ftrace_add_rec_direct(ip, addr, &free_hash);
5316 if (!entry)
5317 goto out_unlock;
5318
5319 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5320
5321 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5322 ret = register_ftrace_function_nolock(&direct_ops);
5323 if (ret)
5324 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5325 }
5326
5327 if (ret) {
5328 remove_hash_entry(direct_functions, entry);
5329 kfree(entry);
5330 if (!direct->count) {
5331 list_del_rcu(&direct->next);
5332 synchronize_rcu_tasks();
5333 kfree(direct);
5334 if (free_hash)
5335 free_ftrace_hash(free_hash);
5336 free_hash = NULL;
5337 ftrace_direct_func_count--;
5338 }
5339 } else {
5340 direct->count++;
5341 }
5342 out_unlock:
5343 mutex_unlock(&direct_mutex);
5344
5345 if (free_hash) {
5346 synchronize_rcu_tasks();
5347 free_ftrace_hash(free_hash);
5348 }
5349
5350 return ret;
5351}
5352EXPORT_SYMBOL_GPL(register_ftrace_direct);
5353
5354static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5355 struct dyn_ftrace **recp)
5356{
5357 struct ftrace_func_entry *entry;
5358 struct dyn_ftrace *rec;
5359
5360 rec = lookup_rec(*ip, *ip);
5361 if (!rec)
5362 return NULL;
5363
5364 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5365 if (!entry) {
5366 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5367 return NULL;
5368 }
5369
5370 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5371
5372 /* Passed in ip just needs to be on the call site */
5373 *ip = rec->ip;
5374
5375 if (recp)
5376 *recp = rec;
5377
5378 return entry;
5379}
5380
5381int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5382{
5383 struct ftrace_direct_func *direct;
5384 struct ftrace_func_entry *entry;
5385 struct ftrace_hash *hash;
5386 int ret = -ENODEV;
5387
5388 mutex_lock(&direct_mutex);
5389
5390 ip = ftrace_location(ip);
5391 if (!ip)
5392 goto out_unlock;
5393
5394 entry = find_direct_entry(&ip, NULL);
5395 if (!entry)
5396 goto out_unlock;
5397
5398 hash = direct_ops.func_hash->filter_hash;
5399 if (hash->count == 1)
5400 unregister_ftrace_function(&direct_ops);
5401
5402 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5403
5404 WARN_ON(ret);
5405
5406 remove_hash_entry(direct_functions, entry);
5407
5408 direct = ftrace_find_direct_func(addr);
5409 if (!WARN_ON(!direct)) {
5410 /* This is the good path (see the ! before WARN) */
5411 direct->count--;
5412 WARN_ON(direct->count < 0);
5413 if (!direct->count) {
5414 list_del_rcu(&direct->next);
5415 synchronize_rcu_tasks();
5416 kfree(direct);
5417 kfree(entry);
5418 ftrace_direct_func_count--;
5419 }
5420 }
5421 out_unlock:
5422 mutex_unlock(&direct_mutex);
5423
5424 return ret;
5425}
5426EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5427
5428static struct ftrace_ops stub_ops = {
5429 .func = ftrace_stub,
5430};
5431
5432/**
5433 * ftrace_modify_direct_caller - modify ftrace nop directly
5434 * @entry: The ftrace hash entry of the direct helper for @rec
5435 * @rec: The record representing the function site to patch
5436 * @old_addr: The location that the site at @rec->ip currently calls
5437 * @new_addr: The location that the site at @rec->ip should call
5438 *
5439 * An architecture may overwrite this function to optimize the
5440 * changing of the direct callback on an ftrace nop location.
5441 * This is called with the ftrace_lock mutex held, and no other
5442 * ftrace callbacks are on the associated record (@rec). Thus,
5443 * it is safe to modify the ftrace record, where it should be
5444 * currently calling @old_addr directly, to call @new_addr.
5445 *
5446 * This is called with direct_mutex locked.
5447 *
5448 * Safety checks should be made to make sure that the code at
5449 * @rec->ip is currently calling @old_addr. And this must
5450 * also update entry->direct to @new_addr.
5451 */
5452int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5453 struct dyn_ftrace *rec,
5454 unsigned long old_addr,
5455 unsigned long new_addr)
5456{
5457 unsigned long ip = rec->ip;
5458 int ret;
5459
5460 lockdep_assert_held(&direct_mutex);
5461
5462 /*
5463 * The ftrace_lock was used to determine if the record
5464 * had more than one registered user to it. If it did,
5465 * we needed to prevent that from changing to do the quick
5466 * switch. But if it did not (only a direct caller was attached)
5467 * then this function is called. But this function can deal
5468 * with attached callers to the rec that we care about, and
5469 * since this function uses standard ftrace calls that take
5470 * the ftrace_lock mutex, we need to release it.
5471 */
5472 mutex_unlock(&ftrace_lock);
5473
5474 /*
5475 * By setting a stub function at the same address, we force
5476 * the code to call the iterator and the direct_ops helper.
5477 * This means that @ip does not call the direct call, and
5478 * we can simply modify it.
5479 */
5480 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5481 if (ret)
5482 goto out_lock;
5483
5484 ret = register_ftrace_function_nolock(&stub_ops);
5485 if (ret) {
5486 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5487 goto out_lock;
5488 }
5489
5490 entry->direct = new_addr;
5491
5492 /*
5493 * By removing the stub, we put back the direct call, calling
5494 * the @new_addr.
5495 */
5496 unregister_ftrace_function(&stub_ops);
5497 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5498
5499 out_lock:
5500 mutex_lock(&ftrace_lock);
5501
5502 return ret;
5503}
5504
5505/**
5506 * modify_ftrace_direct - Modify an existing direct call to call something else
5507 * @ip: The instruction pointer to modify
5508 * @old_addr: The address that the current @ip calls directly
5509 * @new_addr: The address that the @ip should call
5510 *
5511 * This modifies a ftrace direct caller at an instruction pointer without
5512 * having to disable it first. The direct call will switch over to the
5513 * @new_addr without missing anything.
5514 *
5515 * Returns: zero on success. Non zero on error, which includes:
5516 * -ENODEV : the @ip given has no direct caller attached
5517 * -EINVAL : the @old_addr does not match the current direct caller
5518 */
5519int modify_ftrace_direct(unsigned long ip,
5520 unsigned long old_addr, unsigned long new_addr)
5521{
5522 struct ftrace_direct_func *direct, *new_direct = NULL;
5523 struct ftrace_func_entry *entry;
5524 struct dyn_ftrace *rec;
5525 int ret = -ENODEV;
5526
5527 mutex_lock(&direct_mutex);
5528
5529 mutex_lock(&ftrace_lock);
5530
5531 ip = ftrace_location(ip);
5532 if (!ip)
5533 goto out_unlock;
5534
5535 entry = find_direct_entry(&ip, &rec);
5536 if (!entry)
5537 goto out_unlock;
5538
5539 ret = -EINVAL;
5540 if (entry->direct != old_addr)
5541 goto out_unlock;
5542
5543 direct = ftrace_find_direct_func(old_addr);
5544 if (WARN_ON(!direct))
5545 goto out_unlock;
5546 if (direct->count > 1) {
5547 ret = -ENOMEM;
5548 new_direct = ftrace_alloc_direct_func(new_addr);
5549 if (!new_direct)
5550 goto out_unlock;
5551 direct->count--;
5552 new_direct->count++;
5553 } else {
5554 direct->addr = new_addr;
5555 }
5556
5557 /*
5558 * If there's no other ftrace callback on the rec->ip location,
5559 * then it can be changed directly by the architecture.
5560 * If there is another caller, then we just need to change the
5561 * direct caller helper to point to @new_addr.
5562 */
5563 if (ftrace_rec_count(rec) == 1) {
5564 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5565 } else {
5566 entry->direct = new_addr;
5567 ret = 0;
5568 }
5569
5570 if (unlikely(ret && new_direct)) {
5571 direct->count++;
5572 list_del_rcu(&new_direct->next);
5573 synchronize_rcu_tasks();
5574 kfree(new_direct);
5575 ftrace_direct_func_count--;
5576 }
5577
5578 out_unlock:
5579 mutex_unlock(&ftrace_lock);
5580 mutex_unlock(&direct_mutex);
5581 return ret;
5582}
5583EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5584
5585#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5586
5587static int check_direct_multi(struct ftrace_ops *ops)
5588{
5589 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5590 return -EINVAL;
5591 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5592 return -EINVAL;
5593 return 0;
5594}
5595
5596static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5597{
5598 struct ftrace_func_entry *entry, *del;
5599 int size, i;
5600
5601 size = 1 << hash->size_bits;
5602 for (i = 0; i < size; i++) {
5603 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5604 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5605 if (del && del->direct == addr) {
5606 remove_hash_entry(direct_functions, del);
5607 kfree(del);
5608 }
5609 }
5610 }
5611}
5612
5613/**
5614 * register_ftrace_direct_multi - Call a custom trampoline directly
5615 * for multiple functions registered in @ops
5616 * @ops: The address of the struct ftrace_ops object
5617 * @addr: The address of the trampoline to call at @ops functions
5618 *
5619 * This is used to connect a direct calls to @addr from the nop locations
5620 * of the functions registered in @ops (with by ftrace_set_filter_ip
5621 * function).
5622 *
5623 * The location that it calls (@addr) must be able to handle a direct call,
5624 * and save the parameters of the function being traced, and restore them
5625 * (or inject new ones if needed), before returning.
5626 *
5627 * Returns:
5628 * 0 on success
5629 * -EINVAL - The @ops object was already registered with this call or
5630 * when there are no functions in @ops object.
5631 * -EBUSY - Another direct function is already attached (there can be only one)
5632 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5633 * -ENOMEM - There was an allocation failure.
5634 */
5635int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5636{
5637 struct ftrace_hash *hash, *free_hash = NULL;
5638 struct ftrace_func_entry *entry, *new;
5639 int err = -EBUSY, size, i;
5640
5641 if (ops->func || ops->trampoline)
5642 return -EINVAL;
5643 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5644 return -EINVAL;
5645 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5646 return -EINVAL;
5647
5648 hash = ops->func_hash->filter_hash;
5649 if (ftrace_hash_empty(hash))
5650 return -EINVAL;
5651
5652 mutex_lock(&direct_mutex);
5653
5654 /* Make sure requested entries are not already registered.. */
5655 size = 1 << hash->size_bits;
5656 for (i = 0; i < size; i++) {
5657 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5658 if (ftrace_find_rec_direct(entry->ip))
5659 goto out_unlock;
5660 }
5661 }
5662
5663 /* ... and insert them to direct_functions hash. */
5664 err = -ENOMEM;
5665 for (i = 0; i < size; i++) {
5666 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5667 new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5668 if (!new)
5669 goto out_remove;
5670 entry->direct = addr;
5671 }
5672 }
5673
5674 ops->func = call_direct_funcs;
5675 ops->flags = MULTI_FLAGS;
5676 ops->trampoline = FTRACE_REGS_ADDR;
5677
5678 err = register_ftrace_function_nolock(ops);
5679
5680 out_remove:
5681 if (err)
5682 remove_direct_functions_hash(hash, addr);
5683
5684 out_unlock:
5685 mutex_unlock(&direct_mutex);
5686
5687 if (free_hash) {
5688 synchronize_rcu_tasks();
5689 free_ftrace_hash(free_hash);
5690 }
5691 return err;
5692}
5693EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
5694
5695/**
5696 * unregister_ftrace_direct_multi - Remove calls to custom trampoline
5697 * previously registered by register_ftrace_direct_multi for @ops object.
5698 * @ops: The address of the struct ftrace_ops object
5699 *
5700 * This is used to remove a direct calls to @addr from the nop locations
5701 * of the functions registered in @ops (with by ftrace_set_filter_ip
5702 * function).
5703 *
5704 * Returns:
5705 * 0 on success
5706 * -EINVAL - The @ops object was not properly registered.
5707 */
5708int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5709{
5710 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5711 int err;
5712
5713 if (check_direct_multi(ops))
5714 return -EINVAL;
5715 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5716 return -EINVAL;
5717
5718 mutex_lock(&direct_mutex);
5719 err = unregister_ftrace_function(ops);
5720 remove_direct_functions_hash(hash, addr);
5721 mutex_unlock(&direct_mutex);
5722
5723 /* cleanup for possible another register call */
5724 ops->func = NULL;
5725 ops->trampoline = 0;
5726 return err;
5727}
5728EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
5729
5730static int
5731__modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5732{
5733 struct ftrace_hash *hash;
5734 struct ftrace_func_entry *entry, *iter;
5735 static struct ftrace_ops tmp_ops = {
5736 .func = ftrace_stub,
5737 .flags = FTRACE_OPS_FL_STUB,
5738 };
5739 int i, size;
5740 int err;
5741
5742 lockdep_assert_held_once(&direct_mutex);
5743
5744 /* Enable the tmp_ops to have the same functions as the direct ops */
5745 ftrace_ops_init(&tmp_ops);
5746 tmp_ops.func_hash = ops->func_hash;
5747
5748 err = register_ftrace_function_nolock(&tmp_ops);
5749 if (err)
5750 return err;
5751
5752 /*
5753 * Now the ftrace_ops_list_func() is called to do the direct callers.
5754 * We can safely change the direct functions attached to each entry.
5755 */
5756 mutex_lock(&ftrace_lock);
5757
5758 hash = ops->func_hash->filter_hash;
5759 size = 1 << hash->size_bits;
5760 for (i = 0; i < size; i++) {
5761 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5762 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5763 if (!entry)
5764 continue;
5765 entry->direct = addr;
5766 }
5767 }
5768
5769 mutex_unlock(&ftrace_lock);
5770
5771 /* Removing the tmp_ops will add the updated direct callers to the functions */
5772 unregister_ftrace_function(&tmp_ops);
5773
5774 return err;
5775}
5776
5777/**
5778 * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
5779 * to call something else
5780 * @ops: The address of the struct ftrace_ops object
5781 * @addr: The address of the new trampoline to call at @ops functions
5782 *
5783 * This is used to unregister currently registered direct caller and
5784 * register new one @addr on functions registered in @ops object.
5785 *
5786 * Note there's window between ftrace_shutdown and ftrace_startup calls
5787 * where there will be no callbacks called.
5788 *
5789 * Caller should already have direct_mutex locked, so we don't lock
5790 * direct_mutex here.
5791 *
5792 * Returns: zero on success. Non zero on error, which includes:
5793 * -EINVAL - The @ops object was not properly registered.
5794 */
5795int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
5796{
5797 if (check_direct_multi(ops))
5798 return -EINVAL;
5799 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5800 return -EINVAL;
5801
5802 return __modify_ftrace_direct_multi(ops, addr);
5803}
5804EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
5805
5806/**
5807 * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
5808 * to call something else
5809 * @ops: The address of the struct ftrace_ops object
5810 * @addr: The address of the new trampoline to call at @ops functions
5811 *
5812 * This is used to unregister currently registered direct caller and
5813 * register new one @addr on functions registered in @ops object.
5814 *
5815 * Note there's window between ftrace_shutdown and ftrace_startup calls
5816 * where there will be no callbacks called.
5817 *
5818 * Returns: zero on success. Non zero on error, which includes:
5819 * -EINVAL - The @ops object was not properly registered.
5820 */
5821int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5822{
5823 int err;
5824
5825 if (check_direct_multi(ops))
5826 return -EINVAL;
5827 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5828 return -EINVAL;
5829
5830 mutex_lock(&direct_mutex);
5831 err = __modify_ftrace_direct_multi(ops, addr);
5832 mutex_unlock(&direct_mutex);
5833 return err;
5834}
5835EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
5836#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5837
5838/**
5839 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5840 * @ops - the ops to set the filter with
5841 * @ip - the address to add to or remove from the filter.
5842 * @remove - non zero to remove the ip from the filter
5843 * @reset - non zero to reset all filters before applying this filter.
5844 *
5845 * Filters denote which functions should be enabled when tracing is enabled
5846 * If @ip is NULL, it fails to update filter.
5847 *
5848 * This can allocate memory which must be freed before @ops can be freed,
5849 * either by removing each filtered addr or by using
5850 * ftrace_free_filter(@ops).
5851 */
5852int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5853 int remove, int reset)
5854{
5855 ftrace_ops_init(ops);
5856 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5857}
5858EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5859
5860/**
5861 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5862 * @ops - the ops to set the filter with
5863 * @ips - the array of addresses to add to or remove from the filter.
5864 * @cnt - the number of addresses in @ips
5865 * @remove - non zero to remove ips from the filter
5866 * @reset - non zero to reset all filters before applying this filter.
5867 *
5868 * Filters denote which functions should be enabled when tracing is enabled
5869 * If @ips array or any ip specified within is NULL , it fails to update filter.
5870 *
5871 * This can allocate memory which must be freed before @ops can be freed,
5872 * either by removing each filtered addr or by using
5873 * ftrace_free_filter(@ops).
5874*/
5875int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5876 unsigned int cnt, int remove, int reset)
5877{
5878 ftrace_ops_init(ops);
5879 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5880}
5881EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5882
5883/**
5884 * ftrace_ops_set_global_filter - setup ops to use global filters
5885 * @ops - the ops which will use the global filters
5886 *
5887 * ftrace users who need global function trace filtering should call this.
5888 * It can set the global filter only if ops were not initialized before.
5889 */
5890void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5891{
5892 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5893 return;
5894
5895 ftrace_ops_init(ops);
5896 ops->func_hash = &global_ops.local_hash;
5897}
5898EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5899
5900static int
5901ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5902 int reset, int enable)
5903{
5904 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5905}
5906
5907/**
5908 * ftrace_set_filter - set a function to filter on in ftrace
5909 * @ops - the ops to set the filter with
5910 * @buf - the string that holds the function filter text.
5911 * @len - the length of the string.
5912 * @reset - non zero to reset all filters before applying this filter.
5913 *
5914 * Filters denote which functions should be enabled when tracing is enabled.
5915 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5916 *
5917 * This can allocate memory which must be freed before @ops can be freed,
5918 * either by removing each filtered addr or by using
5919 * ftrace_free_filter(@ops).
5920 */
5921int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5922 int len, int reset)
5923{
5924 ftrace_ops_init(ops);
5925 return ftrace_set_regex(ops, buf, len, reset, 1);
5926}
5927EXPORT_SYMBOL_GPL(ftrace_set_filter);
5928
5929/**
5930 * ftrace_set_notrace - set a function to not trace in ftrace
5931 * @ops - the ops to set the notrace filter with
5932 * @buf - the string that holds the function notrace text.
5933 * @len - the length of the string.
5934 * @reset - non zero to reset all filters before applying this filter.
5935 *
5936 * Notrace Filters denote which functions should not be enabled when tracing
5937 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5938 * for tracing.
5939 *
5940 * This can allocate memory which must be freed before @ops can be freed,
5941 * either by removing each filtered addr or by using
5942 * ftrace_free_filter(@ops).
5943 */
5944int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5945 int len, int reset)
5946{
5947 ftrace_ops_init(ops);
5948 return ftrace_set_regex(ops, buf, len, reset, 0);
5949}
5950EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5951/**
5952 * ftrace_set_global_filter - set a function to filter on with global tracers
5953 * @buf - the string that holds the function filter text.
5954 * @len - the length of the string.
5955 * @reset - non zero to reset all filters before applying this filter.
5956 *
5957 * Filters denote which functions should be enabled when tracing is enabled.
5958 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5959 */
5960void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5961{
5962 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5963}
5964EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5965
5966/**
5967 * ftrace_set_global_notrace - set a function to not trace with global tracers
5968 * @buf - the string that holds the function notrace text.
5969 * @len - the length of the string.
5970 * @reset - non zero to reset all filters before applying this filter.
5971 *
5972 * Notrace Filters denote which functions should not be enabled when tracing
5973 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5974 * for tracing.
5975 */
5976void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5977{
5978 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5979}
5980EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5981
5982/*
5983 * command line interface to allow users to set filters on boot up.
5984 */
5985#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5986static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5987static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5988
5989/* Used by function selftest to not test if filter is set */
5990bool ftrace_filter_param __initdata;
5991
5992static int __init set_ftrace_notrace(char *str)
5993{
5994 ftrace_filter_param = true;
5995 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5996 return 1;
5997}
5998__setup("ftrace_notrace=", set_ftrace_notrace);
5999
6000static int __init set_ftrace_filter(char *str)
6001{
6002 ftrace_filter_param = true;
6003 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
6004 return 1;
6005}
6006__setup("ftrace_filter=", set_ftrace_filter);
6007
6008#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6009static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
6010static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
6011static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
6012
6013static int __init set_graph_function(char *str)
6014{
6015 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
6016 return 1;
6017}
6018__setup("ftrace_graph_filter=", set_graph_function);
6019
6020static int __init set_graph_notrace_function(char *str)
6021{
6022 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
6023 return 1;
6024}
6025__setup("ftrace_graph_notrace=", set_graph_notrace_function);
6026
6027static int __init set_graph_max_depth_function(char *str)
6028{
6029 if (!str)
6030 return 0;
6031 fgraph_max_depth = simple_strtoul(str, NULL, 0);
6032 return 1;
6033}
6034__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
6035
6036static void __init set_ftrace_early_graph(char *buf, int enable)
6037{
6038 int ret;
6039 char *func;
6040 struct ftrace_hash *hash;
6041
6042 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
6043 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
6044 return;
6045
6046 while (buf) {
6047 func = strsep(&buf, ",");
6048 /* we allow only one expression at a time */
6049 ret = ftrace_graph_set_hash(hash, func);
6050 if (ret)
6051 printk(KERN_DEBUG "ftrace: function %s not "
6052 "traceable\n", func);
6053 }
6054
6055 if (enable)
6056 ftrace_graph_hash = hash;
6057 else
6058 ftrace_graph_notrace_hash = hash;
6059}
6060#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6061
6062void __init
6063ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
6064{
6065 char *func;
6066
6067 ftrace_ops_init(ops);
6068
6069 while (buf) {
6070 func = strsep(&buf, ",");
6071 ftrace_set_regex(ops, func, strlen(func), 0, enable);
6072 }
6073}
6074
6075static void __init set_ftrace_early_filters(void)
6076{
6077 if (ftrace_filter_buf[0])
6078 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
6079 if (ftrace_notrace_buf[0])
6080 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
6081#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6082 if (ftrace_graph_buf[0])
6083 set_ftrace_early_graph(ftrace_graph_buf, 1);
6084 if (ftrace_graph_notrace_buf[0])
6085 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
6086#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6087}
6088
6089int ftrace_regex_release(struct inode *inode, struct file *file)
6090{
6091 struct seq_file *m = (struct seq_file *)file->private_data;
6092 struct ftrace_iterator *iter;
6093 struct ftrace_hash **orig_hash;
6094 struct trace_parser *parser;
6095 int filter_hash;
6096
6097 if (file->f_mode & FMODE_READ) {
6098 iter = m->private;
6099 seq_release(inode, file);
6100 } else
6101 iter = file->private_data;
6102
6103 parser = &iter->parser;
6104 if (trace_parser_loaded(parser)) {
6105 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
6106
6107 ftrace_process_regex(iter, parser->buffer,
6108 parser->idx, enable);
6109 }
6110
6111 trace_parser_put(parser);
6112
6113 mutex_lock(&iter->ops->func_hash->regex_lock);
6114
6115 if (file->f_mode & FMODE_WRITE) {
6116 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
6117
6118 if (filter_hash) {
6119 orig_hash = &iter->ops->func_hash->filter_hash;
6120 if (iter->tr) {
6121 if (list_empty(&iter->tr->mod_trace))
6122 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
6123 else
6124 iter->hash->flags |= FTRACE_HASH_FL_MOD;
6125 }
6126 } else
6127 orig_hash = &iter->ops->func_hash->notrace_hash;
6128
6129 mutex_lock(&ftrace_lock);
6130 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
6131 iter->hash, filter_hash);
6132 mutex_unlock(&ftrace_lock);
6133 } else {
6134 /* For read only, the hash is the ops hash */
6135 iter->hash = NULL;
6136 }
6137
6138 mutex_unlock(&iter->ops->func_hash->regex_lock);
6139 free_ftrace_hash(iter->hash);
6140 if (iter->tr)
6141 trace_array_put(iter->tr);
6142 kfree(iter);
6143
6144 return 0;
6145}
6146
6147static const struct file_operations ftrace_avail_fops = {
6148 .open = ftrace_avail_open,
6149 .read = seq_read,
6150 .llseek = seq_lseek,
6151 .release = seq_release_private,
6152};
6153
6154static const struct file_operations ftrace_enabled_fops = {
6155 .open = ftrace_enabled_open,
6156 .read = seq_read,
6157 .llseek = seq_lseek,
6158 .release = seq_release_private,
6159};
6160
6161static const struct file_operations ftrace_filter_fops = {
6162 .open = ftrace_filter_open,
6163 .read = seq_read,
6164 .write = ftrace_filter_write,
6165 .llseek = tracing_lseek,
6166 .release = ftrace_regex_release,
6167};
6168
6169static const struct file_operations ftrace_notrace_fops = {
6170 .open = ftrace_notrace_open,
6171 .read = seq_read,
6172 .write = ftrace_notrace_write,
6173 .llseek = tracing_lseek,
6174 .release = ftrace_regex_release,
6175};
6176
6177#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6178
6179static DEFINE_MUTEX(graph_lock);
6180
6181struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
6182struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
6183
6184enum graph_filter_type {
6185 GRAPH_FILTER_NOTRACE = 0,
6186 GRAPH_FILTER_FUNCTION,
6187};
6188
6189#define FTRACE_GRAPH_EMPTY ((void *)1)
6190
6191struct ftrace_graph_data {
6192 struct ftrace_hash *hash;
6193 struct ftrace_func_entry *entry;
6194 int idx; /* for hash table iteration */
6195 enum graph_filter_type type;
6196 struct ftrace_hash *new_hash;
6197 const struct seq_operations *seq_ops;
6198 struct trace_parser parser;
6199};
6200
6201static void *
6202__g_next(struct seq_file *m, loff_t *pos)
6203{
6204 struct ftrace_graph_data *fgd = m->private;
6205 struct ftrace_func_entry *entry = fgd->entry;
6206 struct hlist_head *head;
6207 int i, idx = fgd->idx;
6208
6209 if (*pos >= fgd->hash->count)
6210 return NULL;
6211
6212 if (entry) {
6213 hlist_for_each_entry_continue(entry, hlist) {
6214 fgd->entry = entry;
6215 return entry;
6216 }
6217
6218 idx++;
6219 }
6220
6221 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6222 head = &fgd->hash->buckets[i];
6223 hlist_for_each_entry(entry, head, hlist) {
6224 fgd->entry = entry;
6225 fgd->idx = i;
6226 return entry;
6227 }
6228 }
6229 return NULL;
6230}
6231
6232static void *
6233g_next(struct seq_file *m, void *v, loff_t *pos)
6234{
6235 (*pos)++;
6236 return __g_next(m, pos);
6237}
6238
6239static void *g_start(struct seq_file *m, loff_t *pos)
6240{
6241 struct ftrace_graph_data *fgd = m->private;
6242
6243 mutex_lock(&graph_lock);
6244
6245 if (fgd->type == GRAPH_FILTER_FUNCTION)
6246 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6247 lockdep_is_held(&graph_lock));
6248 else
6249 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6250 lockdep_is_held(&graph_lock));
6251
6252 /* Nothing, tell g_show to print all functions are enabled */
6253 if (ftrace_hash_empty(fgd->hash) && !*pos)
6254 return FTRACE_GRAPH_EMPTY;
6255
6256 fgd->idx = 0;
6257 fgd->entry = NULL;
6258 return __g_next(m, pos);
6259}
6260
6261static void g_stop(struct seq_file *m, void *p)
6262{
6263 mutex_unlock(&graph_lock);
6264}
6265
6266static int g_show(struct seq_file *m, void *v)
6267{
6268 struct ftrace_func_entry *entry = v;
6269
6270 if (!entry)
6271 return 0;
6272
6273 if (entry == FTRACE_GRAPH_EMPTY) {
6274 struct ftrace_graph_data *fgd = m->private;
6275
6276 if (fgd->type == GRAPH_FILTER_FUNCTION)
6277 seq_puts(m, "#### all functions enabled ####\n");
6278 else
6279 seq_puts(m, "#### no functions disabled ####\n");
6280 return 0;
6281 }
6282
6283 seq_printf(m, "%ps\n", (void *)entry->ip);
6284
6285 return 0;
6286}
6287
6288static const struct seq_operations ftrace_graph_seq_ops = {
6289 .start = g_start,
6290 .next = g_next,
6291 .stop = g_stop,
6292 .show = g_show,
6293};
6294
6295static int
6296__ftrace_graph_open(struct inode *inode, struct file *file,
6297 struct ftrace_graph_data *fgd)
6298{
6299 int ret;
6300 struct ftrace_hash *new_hash = NULL;
6301
6302 ret = security_locked_down(LOCKDOWN_TRACEFS);
6303 if (ret)
6304 return ret;
6305
6306 if (file->f_mode & FMODE_WRITE) {
6307 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6308
6309 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6310 return -ENOMEM;
6311
6312 if (file->f_flags & O_TRUNC)
6313 new_hash = alloc_ftrace_hash(size_bits);
6314 else
6315 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6316 fgd->hash);
6317 if (!new_hash) {
6318 ret = -ENOMEM;
6319 goto out;
6320 }
6321 }
6322
6323 if (file->f_mode & FMODE_READ) {
6324 ret = seq_open(file, &ftrace_graph_seq_ops);
6325 if (!ret) {
6326 struct seq_file *m = file->private_data;
6327 m->private = fgd;
6328 } else {
6329 /* Failed */
6330 free_ftrace_hash(new_hash);
6331 new_hash = NULL;
6332 }
6333 } else
6334 file->private_data = fgd;
6335
6336out:
6337 if (ret < 0 && file->f_mode & FMODE_WRITE)
6338 trace_parser_put(&fgd->parser);
6339
6340 fgd->new_hash = new_hash;
6341
6342 /*
6343 * All uses of fgd->hash must be taken with the graph_lock
6344 * held. The graph_lock is going to be released, so force
6345 * fgd->hash to be reinitialized when it is taken again.
6346 */
6347 fgd->hash = NULL;
6348
6349 return ret;
6350}
6351
6352static int
6353ftrace_graph_open(struct inode *inode, struct file *file)
6354{
6355 struct ftrace_graph_data *fgd;
6356 int ret;
6357
6358 if (unlikely(ftrace_disabled))
6359 return -ENODEV;
6360
6361 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6362 if (fgd == NULL)
6363 return -ENOMEM;
6364
6365 mutex_lock(&graph_lock);
6366
6367 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6368 lockdep_is_held(&graph_lock));
6369 fgd->type = GRAPH_FILTER_FUNCTION;
6370 fgd->seq_ops = &ftrace_graph_seq_ops;
6371
6372 ret = __ftrace_graph_open(inode, file, fgd);
6373 if (ret < 0)
6374 kfree(fgd);
6375
6376 mutex_unlock(&graph_lock);
6377 return ret;
6378}
6379
6380static int
6381ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6382{
6383 struct ftrace_graph_data *fgd;
6384 int ret;
6385
6386 if (unlikely(ftrace_disabled))
6387 return -ENODEV;
6388
6389 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6390 if (fgd == NULL)
6391 return -ENOMEM;
6392
6393 mutex_lock(&graph_lock);
6394
6395 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6396 lockdep_is_held(&graph_lock));
6397 fgd->type = GRAPH_FILTER_NOTRACE;
6398 fgd->seq_ops = &ftrace_graph_seq_ops;
6399
6400 ret = __ftrace_graph_open(inode, file, fgd);
6401 if (ret < 0)
6402 kfree(fgd);
6403
6404 mutex_unlock(&graph_lock);
6405 return ret;
6406}
6407
6408static int
6409ftrace_graph_release(struct inode *inode, struct file *file)
6410{
6411 struct ftrace_graph_data *fgd;
6412 struct ftrace_hash *old_hash, *new_hash;
6413 struct trace_parser *parser;
6414 int ret = 0;
6415
6416 if (file->f_mode & FMODE_READ) {
6417 struct seq_file *m = file->private_data;
6418
6419 fgd = m->private;
6420 seq_release(inode, file);
6421 } else {
6422 fgd = file->private_data;
6423 }
6424
6425
6426 if (file->f_mode & FMODE_WRITE) {
6427
6428 parser = &fgd->parser;
6429
6430 if (trace_parser_loaded((parser))) {
6431 ret = ftrace_graph_set_hash(fgd->new_hash,
6432 parser->buffer);
6433 }
6434
6435 trace_parser_put(parser);
6436
6437 new_hash = __ftrace_hash_move(fgd->new_hash);
6438 if (!new_hash) {
6439 ret = -ENOMEM;
6440 goto out;
6441 }
6442
6443 mutex_lock(&graph_lock);
6444
6445 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6446 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6447 lockdep_is_held(&graph_lock));
6448 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6449 } else {
6450 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6451 lockdep_is_held(&graph_lock));
6452 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6453 }
6454
6455 mutex_unlock(&graph_lock);
6456
6457 /*
6458 * We need to do a hard force of sched synchronization.
6459 * This is because we use preempt_disable() to do RCU, but
6460 * the function tracers can be called where RCU is not watching
6461 * (like before user_exit()). We can not rely on the RCU
6462 * infrastructure to do the synchronization, thus we must do it
6463 * ourselves.
6464 */
6465 if (old_hash != EMPTY_HASH)
6466 synchronize_rcu_tasks_rude();
6467
6468 free_ftrace_hash(old_hash);
6469 }
6470
6471 out:
6472 free_ftrace_hash(fgd->new_hash);
6473 kfree(fgd);
6474
6475 return ret;
6476}
6477
6478static int
6479ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6480{
6481 struct ftrace_glob func_g;
6482 struct dyn_ftrace *rec;
6483 struct ftrace_page *pg;
6484 struct ftrace_func_entry *entry;
6485 int fail = 1;
6486 int not;
6487
6488 /* decode regex */
6489 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6490 &func_g.search, ¬);
6491
6492 func_g.len = strlen(func_g.search);
6493
6494 mutex_lock(&ftrace_lock);
6495
6496 if (unlikely(ftrace_disabled)) {
6497 mutex_unlock(&ftrace_lock);
6498 return -ENODEV;
6499 }
6500
6501 do_for_each_ftrace_rec(pg, rec) {
6502
6503 if (rec->flags & FTRACE_FL_DISABLED)
6504 continue;
6505
6506 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6507 entry = ftrace_lookup_ip(hash, rec->ip);
6508
6509 if (!not) {
6510 fail = 0;
6511
6512 if (entry)
6513 continue;
6514 if (add_hash_entry(hash, rec->ip) < 0)
6515 goto out;
6516 } else {
6517 if (entry) {
6518 free_hash_entry(hash, entry);
6519 fail = 0;
6520 }
6521 }
6522 }
6523 } while_for_each_ftrace_rec();
6524out:
6525 mutex_unlock(&ftrace_lock);
6526
6527 if (fail)
6528 return -EINVAL;
6529
6530 return 0;
6531}
6532
6533static ssize_t
6534ftrace_graph_write(struct file *file, const char __user *ubuf,
6535 size_t cnt, loff_t *ppos)
6536{
6537 ssize_t read, ret = 0;
6538 struct ftrace_graph_data *fgd = file->private_data;
6539 struct trace_parser *parser;
6540
6541 if (!cnt)
6542 return 0;
6543
6544 /* Read mode uses seq functions */
6545 if (file->f_mode & FMODE_READ) {
6546 struct seq_file *m = file->private_data;
6547 fgd = m->private;
6548 }
6549
6550 parser = &fgd->parser;
6551
6552 read = trace_get_user(parser, ubuf, cnt, ppos);
6553
6554 if (read >= 0 && trace_parser_loaded(parser) &&
6555 !trace_parser_cont(parser)) {
6556
6557 ret = ftrace_graph_set_hash(fgd->new_hash,
6558 parser->buffer);
6559 trace_parser_clear(parser);
6560 }
6561
6562 if (!ret)
6563 ret = read;
6564
6565 return ret;
6566}
6567
6568static const struct file_operations ftrace_graph_fops = {
6569 .open = ftrace_graph_open,
6570 .read = seq_read,
6571 .write = ftrace_graph_write,
6572 .llseek = tracing_lseek,
6573 .release = ftrace_graph_release,
6574};
6575
6576static const struct file_operations ftrace_graph_notrace_fops = {
6577 .open = ftrace_graph_notrace_open,
6578 .read = seq_read,
6579 .write = ftrace_graph_write,
6580 .llseek = tracing_lseek,
6581 .release = ftrace_graph_release,
6582};
6583#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6584
6585void ftrace_create_filter_files(struct ftrace_ops *ops,
6586 struct dentry *parent)
6587{
6588
6589 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6590 ops, &ftrace_filter_fops);
6591
6592 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6593 ops, &ftrace_notrace_fops);
6594}
6595
6596/*
6597 * The name "destroy_filter_files" is really a misnomer. Although
6598 * in the future, it may actually delete the files, but this is
6599 * really intended to make sure the ops passed in are disabled
6600 * and that when this function returns, the caller is free to
6601 * free the ops.
6602 *
6603 * The "destroy" name is only to match the "create" name that this
6604 * should be paired with.
6605 */
6606void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6607{
6608 mutex_lock(&ftrace_lock);
6609 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6610 ftrace_shutdown(ops, 0);
6611 ops->flags |= FTRACE_OPS_FL_DELETED;
6612 ftrace_free_filter(ops);
6613 mutex_unlock(&ftrace_lock);
6614}
6615
6616static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6617{
6618
6619 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6620 d_tracer, NULL, &ftrace_avail_fops);
6621
6622 trace_create_file("enabled_functions", TRACE_MODE_READ,
6623 d_tracer, NULL, &ftrace_enabled_fops);
6624
6625 ftrace_create_filter_files(&global_ops, d_tracer);
6626
6627#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6628 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6629 NULL,
6630 &ftrace_graph_fops);
6631 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6632 NULL,
6633 &ftrace_graph_notrace_fops);
6634#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6635
6636 return 0;
6637}
6638
6639static int ftrace_cmp_ips(const void *a, const void *b)
6640{
6641 const unsigned long *ipa = a;
6642 const unsigned long *ipb = b;
6643
6644 if (*ipa > *ipb)
6645 return 1;
6646 if (*ipa < *ipb)
6647 return -1;
6648 return 0;
6649}
6650
6651#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6652static void test_is_sorted(unsigned long *start, unsigned long count)
6653{
6654 int i;
6655
6656 for (i = 1; i < count; i++) {
6657 if (WARN(start[i - 1] > start[i],
6658 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6659 (void *)start[i - 1], start[i - 1],
6660 (void *)start[i], start[i]))
6661 break;
6662 }
6663 if (i == count)
6664 pr_info("ftrace section at %px sorted properly\n", start);
6665}
6666#else
6667static void test_is_sorted(unsigned long *start, unsigned long count)
6668{
6669}
6670#endif
6671
6672static int ftrace_process_locs(struct module *mod,
6673 unsigned long *start,
6674 unsigned long *end)
6675{
6676 struct ftrace_page *start_pg;
6677 struct ftrace_page *pg;
6678 struct dyn_ftrace *rec;
6679 unsigned long count;
6680 unsigned long *p;
6681 unsigned long addr;
6682 unsigned long flags = 0; /* Shut up gcc */
6683 int ret = -ENOMEM;
6684
6685 count = end - start;
6686
6687 if (!count)
6688 return 0;
6689
6690 /*
6691 * Sorting mcount in vmlinux at build time depend on
6692 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6693 * modules can not be sorted at build time.
6694 */
6695 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6696 sort(start, count, sizeof(*start),
6697 ftrace_cmp_ips, NULL);
6698 } else {
6699 test_is_sorted(start, count);
6700 }
6701
6702 start_pg = ftrace_allocate_pages(count);
6703 if (!start_pg)
6704 return -ENOMEM;
6705
6706 mutex_lock(&ftrace_lock);
6707
6708 /*
6709 * Core and each module needs their own pages, as
6710 * modules will free them when they are removed.
6711 * Force a new page to be allocated for modules.
6712 */
6713 if (!mod) {
6714 WARN_ON(ftrace_pages || ftrace_pages_start);
6715 /* First initialization */
6716 ftrace_pages = ftrace_pages_start = start_pg;
6717 } else {
6718 if (!ftrace_pages)
6719 goto out;
6720
6721 if (WARN_ON(ftrace_pages->next)) {
6722 /* Hmm, we have free pages? */
6723 while (ftrace_pages->next)
6724 ftrace_pages = ftrace_pages->next;
6725 }
6726
6727 ftrace_pages->next = start_pg;
6728 }
6729
6730 p = start;
6731 pg = start_pg;
6732 while (p < end) {
6733 unsigned long end_offset;
6734 addr = ftrace_call_adjust(*p++);
6735 /*
6736 * Some architecture linkers will pad between
6737 * the different mcount_loc sections of different
6738 * object files to satisfy alignments.
6739 * Skip any NULL pointers.
6740 */
6741 if (!addr)
6742 continue;
6743
6744 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6745 if (end_offset > PAGE_SIZE << pg->order) {
6746 /* We should have allocated enough */
6747 if (WARN_ON(!pg->next))
6748 break;
6749 pg = pg->next;
6750 }
6751
6752 rec = &pg->records[pg->index++];
6753 rec->ip = addr;
6754 }
6755
6756 /* We should have used all pages */
6757 WARN_ON(pg->next);
6758
6759 /* Assign the last page to ftrace_pages */
6760 ftrace_pages = pg;
6761
6762 /*
6763 * We only need to disable interrupts on start up
6764 * because we are modifying code that an interrupt
6765 * may execute, and the modification is not atomic.
6766 * But for modules, nothing runs the code we modify
6767 * until we are finished with it, and there's no
6768 * reason to cause large interrupt latencies while we do it.
6769 */
6770 if (!mod)
6771 local_irq_save(flags);
6772 ftrace_update_code(mod, start_pg);
6773 if (!mod)
6774 local_irq_restore(flags);
6775 ret = 0;
6776 out:
6777 mutex_unlock(&ftrace_lock);
6778
6779 return ret;
6780}
6781
6782struct ftrace_mod_func {
6783 struct list_head list;
6784 char *name;
6785 unsigned long ip;
6786 unsigned int size;
6787};
6788
6789struct ftrace_mod_map {
6790 struct rcu_head rcu;
6791 struct list_head list;
6792 struct module *mod;
6793 unsigned long start_addr;
6794 unsigned long end_addr;
6795 struct list_head funcs;
6796 unsigned int num_funcs;
6797};
6798
6799static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6800 unsigned long *value, char *type,
6801 char *name, char *module_name,
6802 int *exported)
6803{
6804 struct ftrace_ops *op;
6805
6806 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6807 if (!op->trampoline || symnum--)
6808 continue;
6809 *value = op->trampoline;
6810 *type = 't';
6811 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6812 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6813 *exported = 0;
6814 return 0;
6815 }
6816
6817 return -ERANGE;
6818}
6819
6820#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6821/*
6822 * Check if the current ops references the given ip.
6823 *
6824 * If the ops traces all functions, then it was already accounted for.
6825 * If the ops does not trace the current record function, skip it.
6826 * If the ops ignores the function via notrace filter, skip it.
6827 */
6828static bool
6829ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6830{
6831 /* If ops isn't enabled, ignore it */
6832 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6833 return false;
6834
6835 /* If ops traces all then it includes this function */
6836 if (ops_traces_mod(ops))
6837 return true;
6838
6839 /* The function must be in the filter */
6840 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6841 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6842 return false;
6843
6844 /* If in notrace hash, we ignore it too */
6845 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6846 return false;
6847
6848 return true;
6849}
6850#endif
6851
6852#ifdef CONFIG_MODULES
6853
6854#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6855
6856static LIST_HEAD(ftrace_mod_maps);
6857
6858static int referenced_filters(struct dyn_ftrace *rec)
6859{
6860 struct ftrace_ops *ops;
6861 int cnt = 0;
6862
6863 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6864 if (ops_references_ip(ops, rec->ip)) {
6865 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6866 continue;
6867 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6868 continue;
6869 cnt++;
6870 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6871 rec->flags |= FTRACE_FL_REGS;
6872 if (cnt == 1 && ops->trampoline)
6873 rec->flags |= FTRACE_FL_TRAMP;
6874 else
6875 rec->flags &= ~FTRACE_FL_TRAMP;
6876 }
6877 }
6878
6879 return cnt;
6880}
6881
6882static void
6883clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6884{
6885 struct ftrace_func_entry *entry;
6886 struct dyn_ftrace *rec;
6887 int i;
6888
6889 if (ftrace_hash_empty(hash))
6890 return;
6891
6892 for (i = 0; i < pg->index; i++) {
6893 rec = &pg->records[i];
6894 entry = __ftrace_lookup_ip(hash, rec->ip);
6895 /*
6896 * Do not allow this rec to match again.
6897 * Yeah, it may waste some memory, but will be removed
6898 * if/when the hash is modified again.
6899 */
6900 if (entry)
6901 entry->ip = 0;
6902 }
6903}
6904
6905/* Clear any records from hashes */
6906static void clear_mod_from_hashes(struct ftrace_page *pg)
6907{
6908 struct trace_array *tr;
6909
6910 mutex_lock(&trace_types_lock);
6911 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6912 if (!tr->ops || !tr->ops->func_hash)
6913 continue;
6914 mutex_lock(&tr->ops->func_hash->regex_lock);
6915 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6916 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6917 mutex_unlock(&tr->ops->func_hash->regex_lock);
6918 }
6919 mutex_unlock(&trace_types_lock);
6920}
6921
6922static void ftrace_free_mod_map(struct rcu_head *rcu)
6923{
6924 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6925 struct ftrace_mod_func *mod_func;
6926 struct ftrace_mod_func *n;
6927
6928 /* All the contents of mod_map are now not visible to readers */
6929 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6930 kfree(mod_func->name);
6931 list_del(&mod_func->list);
6932 kfree(mod_func);
6933 }
6934
6935 kfree(mod_map);
6936}
6937
6938void ftrace_release_mod(struct module *mod)
6939{
6940 struct ftrace_mod_map *mod_map;
6941 struct ftrace_mod_map *n;
6942 struct dyn_ftrace *rec;
6943 struct ftrace_page **last_pg;
6944 struct ftrace_page *tmp_page = NULL;
6945 struct ftrace_page *pg;
6946
6947 mutex_lock(&ftrace_lock);
6948
6949 if (ftrace_disabled)
6950 goto out_unlock;
6951
6952 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6953 if (mod_map->mod == mod) {
6954 list_del_rcu(&mod_map->list);
6955 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6956 break;
6957 }
6958 }
6959
6960 /*
6961 * Each module has its own ftrace_pages, remove
6962 * them from the list.
6963 */
6964 last_pg = &ftrace_pages_start;
6965 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6966 rec = &pg->records[0];
6967 if (within_module_core(rec->ip, mod) ||
6968 within_module_init(rec->ip, mod)) {
6969 /*
6970 * As core pages are first, the first
6971 * page should never be a module page.
6972 */
6973 if (WARN_ON(pg == ftrace_pages_start))
6974 goto out_unlock;
6975
6976 /* Check if we are deleting the last page */
6977 if (pg == ftrace_pages)
6978 ftrace_pages = next_to_ftrace_page(last_pg);
6979
6980 ftrace_update_tot_cnt -= pg->index;
6981 *last_pg = pg->next;
6982
6983 pg->next = tmp_page;
6984 tmp_page = pg;
6985 } else
6986 last_pg = &pg->next;
6987 }
6988 out_unlock:
6989 mutex_unlock(&ftrace_lock);
6990
6991 for (pg = tmp_page; pg; pg = tmp_page) {
6992
6993 /* Needs to be called outside of ftrace_lock */
6994 clear_mod_from_hashes(pg);
6995
6996 if (pg->records) {
6997 free_pages((unsigned long)pg->records, pg->order);
6998 ftrace_number_of_pages -= 1 << pg->order;
6999 }
7000 tmp_page = pg->next;
7001 kfree(pg);
7002 ftrace_number_of_groups--;
7003 }
7004}
7005
7006void ftrace_module_enable(struct module *mod)
7007{
7008 struct dyn_ftrace *rec;
7009 struct ftrace_page *pg;
7010
7011 mutex_lock(&ftrace_lock);
7012
7013 if (ftrace_disabled)
7014 goto out_unlock;
7015
7016 /*
7017 * If the tracing is enabled, go ahead and enable the record.
7018 *
7019 * The reason not to enable the record immediately is the
7020 * inherent check of ftrace_make_nop/ftrace_make_call for
7021 * correct previous instructions. Making first the NOP
7022 * conversion puts the module to the correct state, thus
7023 * passing the ftrace_make_call check.
7024 *
7025 * We also delay this to after the module code already set the
7026 * text to read-only, as we now need to set it back to read-write
7027 * so that we can modify the text.
7028 */
7029 if (ftrace_start_up)
7030 ftrace_arch_code_modify_prepare();
7031
7032 do_for_each_ftrace_rec(pg, rec) {
7033 int cnt;
7034 /*
7035 * do_for_each_ftrace_rec() is a double loop.
7036 * module text shares the pg. If a record is
7037 * not part of this module, then skip this pg,
7038 * which the "break" will do.
7039 */
7040 if (!within_module_core(rec->ip, mod) &&
7041 !within_module_init(rec->ip, mod))
7042 break;
7043
7044 /* Weak functions should still be ignored */
7045 if (!test_for_valid_rec(rec)) {
7046 /* Clear all other flags. Should not be enabled anyway */
7047 rec->flags = FTRACE_FL_DISABLED;
7048 continue;
7049 }
7050
7051 cnt = 0;
7052
7053 /*
7054 * When adding a module, we need to check if tracers are
7055 * currently enabled and if they are, and can trace this record,
7056 * we need to enable the module functions as well as update the
7057 * reference counts for those function records.
7058 */
7059 if (ftrace_start_up)
7060 cnt += referenced_filters(rec);
7061
7062 rec->flags &= ~FTRACE_FL_DISABLED;
7063 rec->flags += cnt;
7064
7065 if (ftrace_start_up && cnt) {
7066 int failed = __ftrace_replace_code(rec, 1);
7067 if (failed) {
7068 ftrace_bug(failed, rec);
7069 goto out_loop;
7070 }
7071 }
7072
7073 } while_for_each_ftrace_rec();
7074
7075 out_loop:
7076 if (ftrace_start_up)
7077 ftrace_arch_code_modify_post_process();
7078
7079 out_unlock:
7080 mutex_unlock(&ftrace_lock);
7081
7082 process_cached_mods(mod->name);
7083}
7084
7085void ftrace_module_init(struct module *mod)
7086{
7087 int ret;
7088
7089 if (ftrace_disabled || !mod->num_ftrace_callsites)
7090 return;
7091
7092 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
7093 mod->ftrace_callsites + mod->num_ftrace_callsites);
7094 if (ret)
7095 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
7096 mod->name);
7097}
7098
7099static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7100 struct dyn_ftrace *rec)
7101{
7102 struct ftrace_mod_func *mod_func;
7103 unsigned long symsize;
7104 unsigned long offset;
7105 char str[KSYM_SYMBOL_LEN];
7106 char *modname;
7107 const char *ret;
7108
7109 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
7110 if (!ret)
7111 return;
7112
7113 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
7114 if (!mod_func)
7115 return;
7116
7117 mod_func->name = kstrdup(str, GFP_KERNEL);
7118 if (!mod_func->name) {
7119 kfree(mod_func);
7120 return;
7121 }
7122
7123 mod_func->ip = rec->ip - offset;
7124 mod_func->size = symsize;
7125
7126 mod_map->num_funcs++;
7127
7128 list_add_rcu(&mod_func->list, &mod_map->funcs);
7129}
7130
7131static struct ftrace_mod_map *
7132allocate_ftrace_mod_map(struct module *mod,
7133 unsigned long start, unsigned long end)
7134{
7135 struct ftrace_mod_map *mod_map;
7136
7137 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
7138 if (!mod_map)
7139 return NULL;
7140
7141 mod_map->mod = mod;
7142 mod_map->start_addr = start;
7143 mod_map->end_addr = end;
7144 mod_map->num_funcs = 0;
7145
7146 INIT_LIST_HEAD_RCU(&mod_map->funcs);
7147
7148 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
7149
7150 return mod_map;
7151}
7152
7153static const char *
7154ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
7155 unsigned long addr, unsigned long *size,
7156 unsigned long *off, char *sym)
7157{
7158 struct ftrace_mod_func *found_func = NULL;
7159 struct ftrace_mod_func *mod_func;
7160
7161 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7162 if (addr >= mod_func->ip &&
7163 addr < mod_func->ip + mod_func->size) {
7164 found_func = mod_func;
7165 break;
7166 }
7167 }
7168
7169 if (found_func) {
7170 if (size)
7171 *size = found_func->size;
7172 if (off)
7173 *off = addr - found_func->ip;
7174 if (sym)
7175 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
7176
7177 return found_func->name;
7178 }
7179
7180 return NULL;
7181}
7182
7183const char *
7184ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7185 unsigned long *off, char **modname, char *sym)
7186{
7187 struct ftrace_mod_map *mod_map;
7188 const char *ret = NULL;
7189
7190 /* mod_map is freed via call_rcu() */
7191 preempt_disable();
7192 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7193 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7194 if (ret) {
7195 if (modname)
7196 *modname = mod_map->mod->name;
7197 break;
7198 }
7199 }
7200 preempt_enable();
7201
7202 return ret;
7203}
7204
7205int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7206 char *type, char *name,
7207 char *module_name, int *exported)
7208{
7209 struct ftrace_mod_map *mod_map;
7210 struct ftrace_mod_func *mod_func;
7211 int ret;
7212
7213 preempt_disable();
7214 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7215
7216 if (symnum >= mod_map->num_funcs) {
7217 symnum -= mod_map->num_funcs;
7218 continue;
7219 }
7220
7221 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7222 if (symnum > 1) {
7223 symnum--;
7224 continue;
7225 }
7226
7227 *value = mod_func->ip;
7228 *type = 'T';
7229 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
7230 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7231 *exported = 1;
7232 preempt_enable();
7233 return 0;
7234 }
7235 WARN_ON(1);
7236 break;
7237 }
7238 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7239 module_name, exported);
7240 preempt_enable();
7241 return ret;
7242}
7243
7244#else
7245static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7246 struct dyn_ftrace *rec) { }
7247static inline struct ftrace_mod_map *
7248allocate_ftrace_mod_map(struct module *mod,
7249 unsigned long start, unsigned long end)
7250{
7251 return NULL;
7252}
7253int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7254 char *type, char *name, char *module_name,
7255 int *exported)
7256{
7257 int ret;
7258
7259 preempt_disable();
7260 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7261 module_name, exported);
7262 preempt_enable();
7263 return ret;
7264}
7265#endif /* CONFIG_MODULES */
7266
7267struct ftrace_init_func {
7268 struct list_head list;
7269 unsigned long ip;
7270};
7271
7272/* Clear any init ips from hashes */
7273static void
7274clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7275{
7276 struct ftrace_func_entry *entry;
7277
7278 entry = ftrace_lookup_ip(hash, func->ip);
7279 /*
7280 * Do not allow this rec to match again.
7281 * Yeah, it may waste some memory, but will be removed
7282 * if/when the hash is modified again.
7283 */
7284 if (entry)
7285 entry->ip = 0;
7286}
7287
7288static void
7289clear_func_from_hashes(struct ftrace_init_func *func)
7290{
7291 struct trace_array *tr;
7292
7293 mutex_lock(&trace_types_lock);
7294 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7295 if (!tr->ops || !tr->ops->func_hash)
7296 continue;
7297 mutex_lock(&tr->ops->func_hash->regex_lock);
7298 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7299 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7300 mutex_unlock(&tr->ops->func_hash->regex_lock);
7301 }
7302 mutex_unlock(&trace_types_lock);
7303}
7304
7305static void add_to_clear_hash_list(struct list_head *clear_list,
7306 struct dyn_ftrace *rec)
7307{
7308 struct ftrace_init_func *func;
7309
7310 func = kmalloc(sizeof(*func), GFP_KERNEL);
7311 if (!func) {
7312 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7313 return;
7314 }
7315
7316 func->ip = rec->ip;
7317 list_add(&func->list, clear_list);
7318}
7319
7320void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7321{
7322 unsigned long start = (unsigned long)(start_ptr);
7323 unsigned long end = (unsigned long)(end_ptr);
7324 struct ftrace_page **last_pg = &ftrace_pages_start;
7325 struct ftrace_page *pg;
7326 struct dyn_ftrace *rec;
7327 struct dyn_ftrace key;
7328 struct ftrace_mod_map *mod_map = NULL;
7329 struct ftrace_init_func *func, *func_next;
7330 struct list_head clear_hash;
7331
7332 INIT_LIST_HEAD(&clear_hash);
7333
7334 key.ip = start;
7335 key.flags = end; /* overload flags, as it is unsigned long */
7336
7337 mutex_lock(&ftrace_lock);
7338
7339 /*
7340 * If we are freeing module init memory, then check if
7341 * any tracer is active. If so, we need to save a mapping of
7342 * the module functions being freed with the address.
7343 */
7344 if (mod && ftrace_ops_list != &ftrace_list_end)
7345 mod_map = allocate_ftrace_mod_map(mod, start, end);
7346
7347 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7348 if (end < pg->records[0].ip ||
7349 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7350 continue;
7351 again:
7352 rec = bsearch(&key, pg->records, pg->index,
7353 sizeof(struct dyn_ftrace),
7354 ftrace_cmp_recs);
7355 if (!rec)
7356 continue;
7357
7358 /* rec will be cleared from hashes after ftrace_lock unlock */
7359 add_to_clear_hash_list(&clear_hash, rec);
7360
7361 if (mod_map)
7362 save_ftrace_mod_rec(mod_map, rec);
7363
7364 pg->index--;
7365 ftrace_update_tot_cnt--;
7366 if (!pg->index) {
7367 *last_pg = pg->next;
7368 if (pg->records) {
7369 free_pages((unsigned long)pg->records, pg->order);
7370 ftrace_number_of_pages -= 1 << pg->order;
7371 }
7372 ftrace_number_of_groups--;
7373 kfree(pg);
7374 pg = container_of(last_pg, struct ftrace_page, next);
7375 if (!(*last_pg))
7376 ftrace_pages = pg;
7377 continue;
7378 }
7379 memmove(rec, rec + 1,
7380 (pg->index - (rec - pg->records)) * sizeof(*rec));
7381 /* More than one function may be in this block */
7382 goto again;
7383 }
7384 mutex_unlock(&ftrace_lock);
7385
7386 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7387 clear_func_from_hashes(func);
7388 kfree(func);
7389 }
7390}
7391
7392void __init ftrace_free_init_mem(void)
7393{
7394 void *start = (void *)(&__init_begin);
7395 void *end = (void *)(&__init_end);
7396
7397 ftrace_boot_snapshot();
7398
7399 ftrace_free_mem(NULL, start, end);
7400}
7401
7402int __init __weak ftrace_dyn_arch_init(void)
7403{
7404 return 0;
7405}
7406
7407void __init ftrace_init(void)
7408{
7409 extern unsigned long __start_mcount_loc[];
7410 extern unsigned long __stop_mcount_loc[];
7411 unsigned long count, flags;
7412 int ret;
7413
7414 local_irq_save(flags);
7415 ret = ftrace_dyn_arch_init();
7416 local_irq_restore(flags);
7417 if (ret)
7418 goto failed;
7419
7420 count = __stop_mcount_loc - __start_mcount_loc;
7421 if (!count) {
7422 pr_info("ftrace: No functions to be traced?\n");
7423 goto failed;
7424 }
7425
7426 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7427 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7428
7429 ret = ftrace_process_locs(NULL,
7430 __start_mcount_loc,
7431 __stop_mcount_loc);
7432 if (ret) {
7433 pr_warn("ftrace: failed to allocate entries for functions\n");
7434 goto failed;
7435 }
7436
7437 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7438 ftrace_number_of_pages, ftrace_number_of_groups);
7439
7440 last_ftrace_enabled = ftrace_enabled = 1;
7441
7442 set_ftrace_early_filters();
7443
7444 return;
7445 failed:
7446 ftrace_disabled = 1;
7447}
7448
7449/* Do nothing if arch does not support this */
7450void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7451{
7452}
7453
7454static void ftrace_update_trampoline(struct ftrace_ops *ops)
7455{
7456 unsigned long trampoline = ops->trampoline;
7457
7458 arch_ftrace_update_trampoline(ops);
7459 if (ops->trampoline && ops->trampoline != trampoline &&
7460 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7461 /* Add to kallsyms before the perf events */
7462 ftrace_add_trampoline_to_kallsyms(ops);
7463 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7464 ops->trampoline, ops->trampoline_size, false,
7465 FTRACE_TRAMPOLINE_SYM);
7466 /*
7467 * Record the perf text poke event after the ksymbol register
7468 * event.
7469 */
7470 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7471 (void *)ops->trampoline,
7472 ops->trampoline_size);
7473 }
7474}
7475
7476void ftrace_init_trace_array(struct trace_array *tr)
7477{
7478 INIT_LIST_HEAD(&tr->func_probes);
7479 INIT_LIST_HEAD(&tr->mod_trace);
7480 INIT_LIST_HEAD(&tr->mod_notrace);
7481}
7482#else
7483
7484struct ftrace_ops global_ops = {
7485 .func = ftrace_stub,
7486 .flags = FTRACE_OPS_FL_INITIALIZED |
7487 FTRACE_OPS_FL_PID,
7488};
7489
7490static int __init ftrace_nodyn_init(void)
7491{
7492 ftrace_enabled = 1;
7493 return 0;
7494}
7495core_initcall(ftrace_nodyn_init);
7496
7497static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7498static inline void ftrace_startup_all(int command) { }
7499
7500static void ftrace_update_trampoline(struct ftrace_ops *ops)
7501{
7502}
7503
7504#endif /* CONFIG_DYNAMIC_FTRACE */
7505
7506__init void ftrace_init_global_array_ops(struct trace_array *tr)
7507{
7508 tr->ops = &global_ops;
7509 tr->ops->private = tr;
7510 ftrace_init_trace_array(tr);
7511}
7512
7513void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7514{
7515 /* If we filter on pids, update to use the pid function */
7516 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7517 if (WARN_ON(tr->ops->func != ftrace_stub))
7518 printk("ftrace ops had %pS for function\n",
7519 tr->ops->func);
7520 }
7521 tr->ops->func = func;
7522 tr->ops->private = tr;
7523}
7524
7525void ftrace_reset_array_ops(struct trace_array *tr)
7526{
7527 tr->ops->func = ftrace_stub;
7528}
7529
7530static nokprobe_inline void
7531__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7532 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7533{
7534 struct pt_regs *regs = ftrace_get_regs(fregs);
7535 struct ftrace_ops *op;
7536 int bit;
7537
7538 /*
7539 * The ftrace_test_and_set_recursion() will disable preemption,
7540 * which is required since some of the ops may be dynamically
7541 * allocated, they must be freed after a synchronize_rcu().
7542 */
7543 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7544 if (bit < 0)
7545 return;
7546
7547 do_for_each_ftrace_op(op, ftrace_ops_list) {
7548 /* Stub functions don't need to be called nor tested */
7549 if (op->flags & FTRACE_OPS_FL_STUB)
7550 continue;
7551 /*
7552 * Check the following for each ops before calling their func:
7553 * if RCU flag is set, then rcu_is_watching() must be true
7554 * Otherwise test if the ip matches the ops filter
7555 *
7556 * If any of the above fails then the op->func() is not executed.
7557 */
7558 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7559 ftrace_ops_test(op, ip, regs)) {
7560 if (FTRACE_WARN_ON(!op->func)) {
7561 pr_warn("op=%p %pS\n", op, op);
7562 goto out;
7563 }
7564 op->func(ip, parent_ip, op, fregs);
7565 }
7566 } while_for_each_ftrace_op(op);
7567out:
7568 trace_clear_recursion(bit);
7569}
7570
7571/*
7572 * Some archs only support passing ip and parent_ip. Even though
7573 * the list function ignores the op parameter, we do not want any
7574 * C side effects, where a function is called without the caller
7575 * sending a third parameter.
7576 * Archs are to support both the regs and ftrace_ops at the same time.
7577 * If they support ftrace_ops, it is assumed they support regs.
7578 * If call backs want to use regs, they must either check for regs
7579 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7580 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7581 * An architecture can pass partial regs with ftrace_ops and still
7582 * set the ARCH_SUPPORTS_FTRACE_OPS.
7583 *
7584 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7585 * arch_ftrace_ops_list_func.
7586 */
7587#if ARCH_SUPPORTS_FTRACE_OPS
7588void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7589 struct ftrace_ops *op, struct ftrace_regs *fregs)
7590{
7591 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7592}
7593#else
7594void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7595{
7596 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7597}
7598#endif
7599NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7600
7601/*
7602 * If there's only one function registered but it does not support
7603 * recursion, needs RCU protection, then this function will be called
7604 * by the mcount trampoline.
7605 */
7606static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7607 struct ftrace_ops *op, struct ftrace_regs *fregs)
7608{
7609 int bit;
7610
7611 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7612 if (bit < 0)
7613 return;
7614
7615 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7616 op->func(ip, parent_ip, op, fregs);
7617
7618 trace_clear_recursion(bit);
7619}
7620NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7621
7622/**
7623 * ftrace_ops_get_func - get the function a trampoline should call
7624 * @ops: the ops to get the function for
7625 *
7626 * Normally the mcount trampoline will call the ops->func, but there
7627 * are times that it should not. For example, if the ops does not
7628 * have its own recursion protection, then it should call the
7629 * ftrace_ops_assist_func() instead.
7630 *
7631 * Returns the function that the trampoline should call for @ops.
7632 */
7633ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7634{
7635 /*
7636 * If the function does not handle recursion or needs to be RCU safe,
7637 * then we need to call the assist handler.
7638 */
7639 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7640 FTRACE_OPS_FL_RCU))
7641 return ftrace_ops_assist_func;
7642
7643 return ops->func;
7644}
7645
7646static void
7647ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7648 struct task_struct *prev,
7649 struct task_struct *next,
7650 unsigned int prev_state)
7651{
7652 struct trace_array *tr = data;
7653 struct trace_pid_list *pid_list;
7654 struct trace_pid_list *no_pid_list;
7655
7656 pid_list = rcu_dereference_sched(tr->function_pids);
7657 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7658
7659 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7660 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7661 FTRACE_PID_IGNORE);
7662 else
7663 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7664 next->pid);
7665}
7666
7667static void
7668ftrace_pid_follow_sched_process_fork(void *data,
7669 struct task_struct *self,
7670 struct task_struct *task)
7671{
7672 struct trace_pid_list *pid_list;
7673 struct trace_array *tr = data;
7674
7675 pid_list = rcu_dereference_sched(tr->function_pids);
7676 trace_filter_add_remove_task(pid_list, self, task);
7677
7678 pid_list = rcu_dereference_sched(tr->function_no_pids);
7679 trace_filter_add_remove_task(pid_list, self, task);
7680}
7681
7682static void
7683ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7684{
7685 struct trace_pid_list *pid_list;
7686 struct trace_array *tr = data;
7687
7688 pid_list = rcu_dereference_sched(tr->function_pids);
7689 trace_filter_add_remove_task(pid_list, NULL, task);
7690
7691 pid_list = rcu_dereference_sched(tr->function_no_pids);
7692 trace_filter_add_remove_task(pid_list, NULL, task);
7693}
7694
7695void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7696{
7697 if (enable) {
7698 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7699 tr);
7700 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7701 tr);
7702 } else {
7703 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7704 tr);
7705 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7706 tr);
7707 }
7708}
7709
7710static void clear_ftrace_pids(struct trace_array *tr, int type)
7711{
7712 struct trace_pid_list *pid_list;
7713 struct trace_pid_list *no_pid_list;
7714 int cpu;
7715
7716 pid_list = rcu_dereference_protected(tr->function_pids,
7717 lockdep_is_held(&ftrace_lock));
7718 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7719 lockdep_is_held(&ftrace_lock));
7720
7721 /* Make sure there's something to do */
7722 if (!pid_type_enabled(type, pid_list, no_pid_list))
7723 return;
7724
7725 /* See if the pids still need to be checked after this */
7726 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7727 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7728 for_each_possible_cpu(cpu)
7729 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7730 }
7731
7732 if (type & TRACE_PIDS)
7733 rcu_assign_pointer(tr->function_pids, NULL);
7734
7735 if (type & TRACE_NO_PIDS)
7736 rcu_assign_pointer(tr->function_no_pids, NULL);
7737
7738 /* Wait till all users are no longer using pid filtering */
7739 synchronize_rcu();
7740
7741 if ((type & TRACE_PIDS) && pid_list)
7742 trace_pid_list_free(pid_list);
7743
7744 if ((type & TRACE_NO_PIDS) && no_pid_list)
7745 trace_pid_list_free(no_pid_list);
7746}
7747
7748void ftrace_clear_pids(struct trace_array *tr)
7749{
7750 mutex_lock(&ftrace_lock);
7751
7752 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7753
7754 mutex_unlock(&ftrace_lock);
7755}
7756
7757static void ftrace_pid_reset(struct trace_array *tr, int type)
7758{
7759 mutex_lock(&ftrace_lock);
7760 clear_ftrace_pids(tr, type);
7761
7762 ftrace_update_pid_func();
7763 ftrace_startup_all(0);
7764
7765 mutex_unlock(&ftrace_lock);
7766}
7767
7768/* Greater than any max PID */
7769#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7770
7771static void *fpid_start(struct seq_file *m, loff_t *pos)
7772 __acquires(RCU)
7773{
7774 struct trace_pid_list *pid_list;
7775 struct trace_array *tr = m->private;
7776
7777 mutex_lock(&ftrace_lock);
7778 rcu_read_lock_sched();
7779
7780 pid_list = rcu_dereference_sched(tr->function_pids);
7781
7782 if (!pid_list)
7783 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7784
7785 return trace_pid_start(pid_list, pos);
7786}
7787
7788static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7789{
7790 struct trace_array *tr = m->private;
7791 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7792
7793 if (v == FTRACE_NO_PIDS) {
7794 (*pos)++;
7795 return NULL;
7796 }
7797 return trace_pid_next(pid_list, v, pos);
7798}
7799
7800static void fpid_stop(struct seq_file *m, void *p)
7801 __releases(RCU)
7802{
7803 rcu_read_unlock_sched();
7804 mutex_unlock(&ftrace_lock);
7805}
7806
7807static int fpid_show(struct seq_file *m, void *v)
7808{
7809 if (v == FTRACE_NO_PIDS) {
7810 seq_puts(m, "no pid\n");
7811 return 0;
7812 }
7813
7814 return trace_pid_show(m, v);
7815}
7816
7817static const struct seq_operations ftrace_pid_sops = {
7818 .start = fpid_start,
7819 .next = fpid_next,
7820 .stop = fpid_stop,
7821 .show = fpid_show,
7822};
7823
7824static void *fnpid_start(struct seq_file *m, loff_t *pos)
7825 __acquires(RCU)
7826{
7827 struct trace_pid_list *pid_list;
7828 struct trace_array *tr = m->private;
7829
7830 mutex_lock(&ftrace_lock);
7831 rcu_read_lock_sched();
7832
7833 pid_list = rcu_dereference_sched(tr->function_no_pids);
7834
7835 if (!pid_list)
7836 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7837
7838 return trace_pid_start(pid_list, pos);
7839}
7840
7841static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7842{
7843 struct trace_array *tr = m->private;
7844 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7845
7846 if (v == FTRACE_NO_PIDS) {
7847 (*pos)++;
7848 return NULL;
7849 }
7850 return trace_pid_next(pid_list, v, pos);
7851}
7852
7853static const struct seq_operations ftrace_no_pid_sops = {
7854 .start = fnpid_start,
7855 .next = fnpid_next,
7856 .stop = fpid_stop,
7857 .show = fpid_show,
7858};
7859
7860static int pid_open(struct inode *inode, struct file *file, int type)
7861{
7862 const struct seq_operations *seq_ops;
7863 struct trace_array *tr = inode->i_private;
7864 struct seq_file *m;
7865 int ret = 0;
7866
7867 ret = tracing_check_open_get_tr(tr);
7868 if (ret)
7869 return ret;
7870
7871 if ((file->f_mode & FMODE_WRITE) &&
7872 (file->f_flags & O_TRUNC))
7873 ftrace_pid_reset(tr, type);
7874
7875 switch (type) {
7876 case TRACE_PIDS:
7877 seq_ops = &ftrace_pid_sops;
7878 break;
7879 case TRACE_NO_PIDS:
7880 seq_ops = &ftrace_no_pid_sops;
7881 break;
7882 default:
7883 trace_array_put(tr);
7884 WARN_ON_ONCE(1);
7885 return -EINVAL;
7886 }
7887
7888 ret = seq_open(file, seq_ops);
7889 if (ret < 0) {
7890 trace_array_put(tr);
7891 } else {
7892 m = file->private_data;
7893 /* copy tr over to seq ops */
7894 m->private = tr;
7895 }
7896
7897 return ret;
7898}
7899
7900static int
7901ftrace_pid_open(struct inode *inode, struct file *file)
7902{
7903 return pid_open(inode, file, TRACE_PIDS);
7904}
7905
7906static int
7907ftrace_no_pid_open(struct inode *inode, struct file *file)
7908{
7909 return pid_open(inode, file, TRACE_NO_PIDS);
7910}
7911
7912static void ignore_task_cpu(void *data)
7913{
7914 struct trace_array *tr = data;
7915 struct trace_pid_list *pid_list;
7916 struct trace_pid_list *no_pid_list;
7917
7918 /*
7919 * This function is called by on_each_cpu() while the
7920 * event_mutex is held.
7921 */
7922 pid_list = rcu_dereference_protected(tr->function_pids,
7923 mutex_is_locked(&ftrace_lock));
7924 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7925 mutex_is_locked(&ftrace_lock));
7926
7927 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7928 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7929 FTRACE_PID_IGNORE);
7930 else
7931 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7932 current->pid);
7933}
7934
7935static ssize_t
7936pid_write(struct file *filp, const char __user *ubuf,
7937 size_t cnt, loff_t *ppos, int type)
7938{
7939 struct seq_file *m = filp->private_data;
7940 struct trace_array *tr = m->private;
7941 struct trace_pid_list *filtered_pids;
7942 struct trace_pid_list *other_pids;
7943 struct trace_pid_list *pid_list;
7944 ssize_t ret;
7945
7946 if (!cnt)
7947 return 0;
7948
7949 mutex_lock(&ftrace_lock);
7950
7951 switch (type) {
7952 case TRACE_PIDS:
7953 filtered_pids = rcu_dereference_protected(tr->function_pids,
7954 lockdep_is_held(&ftrace_lock));
7955 other_pids = rcu_dereference_protected(tr->function_no_pids,
7956 lockdep_is_held(&ftrace_lock));
7957 break;
7958 case TRACE_NO_PIDS:
7959 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7960 lockdep_is_held(&ftrace_lock));
7961 other_pids = rcu_dereference_protected(tr->function_pids,
7962 lockdep_is_held(&ftrace_lock));
7963 break;
7964 default:
7965 ret = -EINVAL;
7966 WARN_ON_ONCE(1);
7967 goto out;
7968 }
7969
7970 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7971 if (ret < 0)
7972 goto out;
7973
7974 switch (type) {
7975 case TRACE_PIDS:
7976 rcu_assign_pointer(tr->function_pids, pid_list);
7977 break;
7978 case TRACE_NO_PIDS:
7979 rcu_assign_pointer(tr->function_no_pids, pid_list);
7980 break;
7981 }
7982
7983
7984 if (filtered_pids) {
7985 synchronize_rcu();
7986 trace_pid_list_free(filtered_pids);
7987 } else if (pid_list && !other_pids) {
7988 /* Register a probe to set whether to ignore the tracing of a task */
7989 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7990 }
7991
7992 /*
7993 * Ignoring of pids is done at task switch. But we have to
7994 * check for those tasks that are currently running.
7995 * Always do this in case a pid was appended or removed.
7996 */
7997 on_each_cpu(ignore_task_cpu, tr, 1);
7998
7999 ftrace_update_pid_func();
8000 ftrace_startup_all(0);
8001 out:
8002 mutex_unlock(&ftrace_lock);
8003
8004 if (ret > 0)
8005 *ppos += ret;
8006
8007 return ret;
8008}
8009
8010static ssize_t
8011ftrace_pid_write(struct file *filp, const char __user *ubuf,
8012 size_t cnt, loff_t *ppos)
8013{
8014 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
8015}
8016
8017static ssize_t
8018ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
8019 size_t cnt, loff_t *ppos)
8020{
8021 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
8022}
8023
8024static int
8025ftrace_pid_release(struct inode *inode, struct file *file)
8026{
8027 struct trace_array *tr = inode->i_private;
8028
8029 trace_array_put(tr);
8030
8031 return seq_release(inode, file);
8032}
8033
8034static const struct file_operations ftrace_pid_fops = {
8035 .open = ftrace_pid_open,
8036 .write = ftrace_pid_write,
8037 .read = seq_read,
8038 .llseek = tracing_lseek,
8039 .release = ftrace_pid_release,
8040};
8041
8042static const struct file_operations ftrace_no_pid_fops = {
8043 .open = ftrace_no_pid_open,
8044 .write = ftrace_no_pid_write,
8045 .read = seq_read,
8046 .llseek = tracing_lseek,
8047 .release = ftrace_pid_release,
8048};
8049
8050void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8051{
8052 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
8053 tr, &ftrace_pid_fops);
8054 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
8055 d_tracer, tr, &ftrace_no_pid_fops);
8056}
8057
8058void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
8059 struct dentry *d_tracer)
8060{
8061 /* Only the top level directory has the dyn_tracefs and profile */
8062 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
8063
8064 ftrace_init_dyn_tracefs(d_tracer);
8065 ftrace_profile_tracefs(d_tracer);
8066}
8067
8068/**
8069 * ftrace_kill - kill ftrace
8070 *
8071 * This function should be used by panic code. It stops ftrace
8072 * but in a not so nice way. If you need to simply kill ftrace
8073 * from a non-atomic section, use ftrace_kill.
8074 */
8075void ftrace_kill(void)
8076{
8077 ftrace_disabled = 1;
8078 ftrace_enabled = 0;
8079 ftrace_trace_function = ftrace_stub;
8080}
8081
8082/**
8083 * ftrace_is_dead - Test if ftrace is dead or not.
8084 *
8085 * Returns 1 if ftrace is "dead", zero otherwise.
8086 */
8087int ftrace_is_dead(void)
8088{
8089 return ftrace_disabled;
8090}
8091
8092#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
8093/*
8094 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
8095 * it doesn't conflict with any direct ftrace_ops. If there is existing
8096 * direct ftrace_ops on a kernel function being patched, call
8097 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
8098 *
8099 * @ops: ftrace_ops being registered.
8100 *
8101 * Returns:
8102 * 0 on success;
8103 * Negative on failure.
8104 */
8105static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8106{
8107 struct ftrace_func_entry *entry;
8108 struct ftrace_hash *hash;
8109 struct ftrace_ops *op;
8110 int size, i, ret;
8111
8112 lockdep_assert_held_once(&direct_mutex);
8113
8114 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8115 return 0;
8116
8117 hash = ops->func_hash->filter_hash;
8118 size = 1 << hash->size_bits;
8119 for (i = 0; i < size; i++) {
8120 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8121 unsigned long ip = entry->ip;
8122 bool found_op = false;
8123
8124 mutex_lock(&ftrace_lock);
8125 do_for_each_ftrace_op(op, ftrace_ops_list) {
8126 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8127 continue;
8128 if (ops_references_ip(op, ip)) {
8129 found_op = true;
8130 break;
8131 }
8132 } while_for_each_ftrace_op(op);
8133 mutex_unlock(&ftrace_lock);
8134
8135 if (found_op) {
8136 if (!op->ops_func)
8137 return -EBUSY;
8138
8139 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
8140 if (ret)
8141 return ret;
8142 }
8143 }
8144 }
8145
8146 return 0;
8147}
8148
8149/*
8150 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
8151 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
8152 * ops.
8153 */
8154static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8155{
8156 struct ftrace_func_entry *entry;
8157 struct ftrace_hash *hash;
8158 struct ftrace_ops *op;
8159 int size, i;
8160
8161 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8162 return;
8163
8164 mutex_lock(&direct_mutex);
8165
8166 hash = ops->func_hash->filter_hash;
8167 size = 1 << hash->size_bits;
8168 for (i = 0; i < size; i++) {
8169 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8170 unsigned long ip = entry->ip;
8171 bool found_op = false;
8172
8173 mutex_lock(&ftrace_lock);
8174 do_for_each_ftrace_op(op, ftrace_ops_list) {
8175 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8176 continue;
8177 if (ops_references_ip(op, ip)) {
8178 found_op = true;
8179 break;
8180 }
8181 } while_for_each_ftrace_op(op);
8182 mutex_unlock(&ftrace_lock);
8183
8184 /* The cleanup is optional, ignore any errors */
8185 if (found_op && op->ops_func)
8186 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8187 }
8188 }
8189 mutex_unlock(&direct_mutex);
8190}
8191
8192#define lock_direct_mutex() mutex_lock(&direct_mutex)
8193#define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8194
8195#else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8196
8197static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8198{
8199 return 0;
8200}
8201
8202static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8203{
8204}
8205
8206#define lock_direct_mutex() do { } while (0)
8207#define unlock_direct_mutex() do { } while (0)
8208
8209#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8210
8211/*
8212 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8213 */
8214static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8215{
8216 int ret;
8217
8218 ftrace_ops_init(ops);
8219
8220 mutex_lock(&ftrace_lock);
8221
8222 ret = ftrace_startup(ops, 0);
8223
8224 mutex_unlock(&ftrace_lock);
8225
8226 return ret;
8227}
8228
8229/**
8230 * register_ftrace_function - register a function for profiling
8231 * @ops: ops structure that holds the function for profiling.
8232 *
8233 * Register a function to be called by all functions in the
8234 * kernel.
8235 *
8236 * Note: @ops->func and all the functions it calls must be labeled
8237 * with "notrace", otherwise it will go into a
8238 * recursive loop.
8239 */
8240int register_ftrace_function(struct ftrace_ops *ops)
8241{
8242 int ret;
8243
8244 lock_direct_mutex();
8245 ret = prepare_direct_functions_for_ipmodify(ops);
8246 if (ret < 0)
8247 goto out_unlock;
8248
8249 ret = register_ftrace_function_nolock(ops);
8250
8251out_unlock:
8252 unlock_direct_mutex();
8253 return ret;
8254}
8255EXPORT_SYMBOL_GPL(register_ftrace_function);
8256
8257/**
8258 * unregister_ftrace_function - unregister a function for profiling.
8259 * @ops: ops structure that holds the function to unregister
8260 *
8261 * Unregister a function that was added to be called by ftrace profiling.
8262 */
8263int unregister_ftrace_function(struct ftrace_ops *ops)
8264{
8265 int ret;
8266
8267 mutex_lock(&ftrace_lock);
8268 ret = ftrace_shutdown(ops, 0);
8269 mutex_unlock(&ftrace_lock);
8270
8271 cleanup_direct_functions_after_ipmodify(ops);
8272 return ret;
8273}
8274EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8275
8276static int symbols_cmp(const void *a, const void *b)
8277{
8278 const char **str_a = (const char **) a;
8279 const char **str_b = (const char **) b;
8280
8281 return strcmp(*str_a, *str_b);
8282}
8283
8284struct kallsyms_data {
8285 unsigned long *addrs;
8286 const char **syms;
8287 size_t cnt;
8288 size_t found;
8289};
8290
8291/* This function gets called for all kernel and module symbols
8292 * and returns 1 in case we resolved all the requested symbols,
8293 * 0 otherwise.
8294 */
8295static int kallsyms_callback(void *data, const char *name,
8296 struct module *mod, unsigned long addr)
8297{
8298 struct kallsyms_data *args = data;
8299 const char **sym;
8300 int idx;
8301
8302 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8303 if (!sym)
8304 return 0;
8305
8306 idx = sym - args->syms;
8307 if (args->addrs[idx])
8308 return 0;
8309
8310 if (!ftrace_location(addr))
8311 return 0;
8312
8313 args->addrs[idx] = addr;
8314 args->found++;
8315 return args->found == args->cnt ? 1 : 0;
8316}
8317
8318/**
8319 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8320 *
8321 * @sorted_syms: array of symbols pointers symbols to resolve,
8322 * must be alphabetically sorted
8323 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8324 * @addrs: array for storing resulting addresses
8325 *
8326 * This function looks up addresses for array of symbols provided in
8327 * @syms array (must be alphabetically sorted) and stores them in
8328 * @addrs array, which needs to be big enough to store at least @cnt
8329 * addresses.
8330 *
8331 * This function returns 0 if all provided symbols are found,
8332 * -ESRCH otherwise.
8333 */
8334int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8335{
8336 struct kallsyms_data args;
8337 int found_all;
8338
8339 memset(addrs, 0, sizeof(*addrs) * cnt);
8340 args.addrs = addrs;
8341 args.syms = sorted_syms;
8342 args.cnt = cnt;
8343 args.found = 0;
8344
8345 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8346 if (found_all)
8347 return 0;
8348 found_all = module_kallsyms_on_each_symbol(kallsyms_callback, &args);
8349 return found_all ? 0 : -ESRCH;
8350}
8351
8352#ifdef CONFIG_SYSCTL
8353
8354#ifdef CONFIG_DYNAMIC_FTRACE
8355static void ftrace_startup_sysctl(void)
8356{
8357 int command;
8358
8359 if (unlikely(ftrace_disabled))
8360 return;
8361
8362 /* Force update next time */
8363 saved_ftrace_func = NULL;
8364 /* ftrace_start_up is true if we want ftrace running */
8365 if (ftrace_start_up) {
8366 command = FTRACE_UPDATE_CALLS;
8367 if (ftrace_graph_active)
8368 command |= FTRACE_START_FUNC_RET;
8369 ftrace_startup_enable(command);
8370 }
8371}
8372
8373static void ftrace_shutdown_sysctl(void)
8374{
8375 int command;
8376
8377 if (unlikely(ftrace_disabled))
8378 return;
8379
8380 /* ftrace_start_up is true if ftrace is running */
8381 if (ftrace_start_up) {
8382 command = FTRACE_DISABLE_CALLS;
8383 if (ftrace_graph_active)
8384 command |= FTRACE_STOP_FUNC_RET;
8385 ftrace_run_update_code(command);
8386 }
8387}
8388#else
8389# define ftrace_startup_sysctl() do { } while (0)
8390# define ftrace_shutdown_sysctl() do { } while (0)
8391#endif /* CONFIG_DYNAMIC_FTRACE */
8392
8393static bool is_permanent_ops_registered(void)
8394{
8395 struct ftrace_ops *op;
8396
8397 do_for_each_ftrace_op(op, ftrace_ops_list) {
8398 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8399 return true;
8400 } while_for_each_ftrace_op(op);
8401
8402 return false;
8403}
8404
8405static int
8406ftrace_enable_sysctl(struct ctl_table *table, int write,
8407 void *buffer, size_t *lenp, loff_t *ppos)
8408{
8409 int ret = -ENODEV;
8410
8411 mutex_lock(&ftrace_lock);
8412
8413 if (unlikely(ftrace_disabled))
8414 goto out;
8415
8416 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8417
8418 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8419 goto out;
8420
8421 if (ftrace_enabled) {
8422
8423 /* we are starting ftrace again */
8424 if (rcu_dereference_protected(ftrace_ops_list,
8425 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8426 update_ftrace_function();
8427
8428 ftrace_startup_sysctl();
8429
8430 } else {
8431 if (is_permanent_ops_registered()) {
8432 ftrace_enabled = true;
8433 ret = -EBUSY;
8434 goto out;
8435 }
8436
8437 /* stopping ftrace calls (just send to ftrace_stub) */
8438 ftrace_trace_function = ftrace_stub;
8439
8440 ftrace_shutdown_sysctl();
8441 }
8442
8443 last_ftrace_enabled = !!ftrace_enabled;
8444 out:
8445 mutex_unlock(&ftrace_lock);
8446 return ret;
8447}
8448
8449static struct ctl_table ftrace_sysctls[] = {
8450 {
8451 .procname = "ftrace_enabled",
8452 .data = &ftrace_enabled,
8453 .maxlen = sizeof(int),
8454 .mode = 0644,
8455 .proc_handler = ftrace_enable_sysctl,
8456 },
8457 {}
8458};
8459
8460static int __init ftrace_sysctl_init(void)
8461{
8462 register_sysctl_init("kernel", ftrace_sysctls);
8463 return 0;
8464}
8465late_initcall(ftrace_sysctl_init);
8466#endif