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