b17a30350f06072fb307b03c7ba2d586e5d7f0bd
[linux-2.6.git] / kernel / trace / ftrace.c
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/debugfs.h>
21 #include <linux/hardirq.h>
22 #include <linux/kthread.h>
23 #include <linux/uaccess.h>
24 #include <linux/kprobes.h>
25 #include <linux/ftrace.h>
26 #include <linux/sysctl.h>
27 #include <linux/ctype.h>
28 #include <linux/list.h>
29
30 #include <asm/ftrace.h>
31
32 #include "trace.h"
33
34 #define FTRACE_WARN_ON(cond)                    \
35         do {                                    \
36                 if (WARN_ON(cond))              \
37                         ftrace_kill();          \
38         } while (0)
39
40 #define FTRACE_WARN_ON_ONCE(cond)               \
41         do {                                    \
42                 if (WARN_ON_ONCE(cond))         \
43                         ftrace_kill();          \
44         } while (0)
45
46 /* ftrace_enabled is a method to turn ftrace on or off */
47 int ftrace_enabled __read_mostly;
48 static int last_ftrace_enabled;
49
50 /* ftrace_pid_trace >= 0 will only trace threads with this pid */
51 static int ftrace_pid_trace = -1;
52
53 /* Quick disabling of function tracer. */
54 int function_trace_stop;
55
56 /*
57  * ftrace_disabled is set when an anomaly is discovered.
58  * ftrace_disabled is much stronger than ftrace_enabled.
59  */
60 static int ftrace_disabled __read_mostly;
61
62 static DEFINE_SPINLOCK(ftrace_lock);
63 static DEFINE_MUTEX(ftrace_sysctl_lock);
64 static DEFINE_MUTEX(ftrace_start_lock);
65
66 static struct ftrace_ops ftrace_list_end __read_mostly =
67 {
68         .func = ftrace_stub,
69 };
70
71 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
72 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
73 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
74 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
75
76 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
77 {
78         struct ftrace_ops *op = ftrace_list;
79
80         /* in case someone actually ports this to alpha! */
81         read_barrier_depends();
82
83         while (op != &ftrace_list_end) {
84                 /* silly alpha */
85                 read_barrier_depends();
86                 op->func(ip, parent_ip);
87                 op = op->next;
88         };
89 }
90
91 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
92 {
93         if (current->pid != ftrace_pid_trace)
94                 return;
95
96         ftrace_pid_function(ip, parent_ip);
97 }
98
99 static void set_ftrace_pid_function(ftrace_func_t func)
100 {
101         /* do not set ftrace_pid_function to itself! */
102         if (func != ftrace_pid_func)
103                 ftrace_pid_function = func;
104 }
105
106 /**
107  * clear_ftrace_function - reset the ftrace function
108  *
109  * This NULLs the ftrace function and in essence stops
110  * tracing.  There may be lag
111  */
112 void clear_ftrace_function(void)
113 {
114         ftrace_trace_function = ftrace_stub;
115         __ftrace_trace_function = ftrace_stub;
116         ftrace_pid_function = ftrace_stub;
117 }
118
119 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
120 /*
121  * For those archs that do not test ftrace_trace_stop in their
122  * mcount call site, we need to do it from C.
123  */
124 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
125 {
126         if (function_trace_stop)
127                 return;
128
129         __ftrace_trace_function(ip, parent_ip);
130 }
131 #endif
132
133 static int __register_ftrace_function(struct ftrace_ops *ops)
134 {
135         /* should not be called from interrupt context */
136         spin_lock(&ftrace_lock);
137
138         ops->next = ftrace_list;
139         /*
140          * We are entering ops into the ftrace_list but another
141          * CPU might be walking that list. We need to make sure
142          * the ops->next pointer is valid before another CPU sees
143          * the ops pointer included into the ftrace_list.
144          */
145         smp_wmb();
146         ftrace_list = ops;
147
148         if (ftrace_enabled) {
149                 ftrace_func_t func;
150
151                 if (ops->next == &ftrace_list_end)
152                         func = ops->func;
153                 else
154                         func = ftrace_list_func;
155
156                 if (ftrace_pid_trace >= 0) {
157                         set_ftrace_pid_function(func);
158                         func = ftrace_pid_func;
159                 }
160
161                 /*
162                  * For one func, simply call it directly.
163                  * For more than one func, call the chain.
164                  */
165 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
166                 ftrace_trace_function = func;
167 #else
168                 __ftrace_trace_function = func;
169                 ftrace_trace_function = ftrace_test_stop_func;
170 #endif
171         }
172
173         spin_unlock(&ftrace_lock);
174
175         return 0;
176 }
177
178 static int __unregister_ftrace_function(struct ftrace_ops *ops)
179 {
180         struct ftrace_ops **p;
181         int ret = 0;
182
183         /* should not be called from interrupt context */
184         spin_lock(&ftrace_lock);
185
186         /*
187          * If we are removing the last function, then simply point
188          * to the ftrace_stub.
189          */
190         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
191                 ftrace_trace_function = ftrace_stub;
192                 ftrace_list = &ftrace_list_end;
193                 goto out;
194         }
195
196         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
197                 if (*p == ops)
198                         break;
199
200         if (*p != ops) {
201                 ret = -1;
202                 goto out;
203         }
204
205         *p = (*p)->next;
206
207         if (ftrace_enabled) {
208                 /* If we only have one func left, then call that directly */
209                 if (ftrace_list->next == &ftrace_list_end) {
210                         ftrace_func_t func = ftrace_list->func;
211
212                         if (ftrace_pid_trace >= 0) {
213                                 set_ftrace_pid_function(func);
214                                 func = ftrace_pid_func;
215                         }
216 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
217                         ftrace_trace_function = func;
218 #else
219                         __ftrace_trace_function = func;
220 #endif
221                 }
222         }
223
224  out:
225         spin_unlock(&ftrace_lock);
226
227         return ret;
228 }
229
230 static void ftrace_update_pid_func(void)
231 {
232         ftrace_func_t func;
233
234         /* should not be called from interrupt context */
235         spin_lock(&ftrace_lock);
236
237         if (ftrace_trace_function == ftrace_stub)
238                 goto out;
239
240         func = ftrace_trace_function;
241
242         if (ftrace_pid_trace >= 0) {
243                 set_ftrace_pid_function(func);
244                 func = ftrace_pid_func;
245         } else {
246                 if (func == ftrace_pid_func)
247                         func = ftrace_pid_function;
248         }
249
250 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
251         ftrace_trace_function = func;
252 #else
253         __ftrace_trace_function = func;
254 #endif
255
256  out:
257         spin_unlock(&ftrace_lock);
258 }
259
260 #ifdef CONFIG_DYNAMIC_FTRACE
261 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
262 # error Dynamic ftrace depends on MCOUNT_RECORD
263 #endif
264
265 /*
266  * Since MCOUNT_ADDR may point to mcount itself, we do not want
267  * to get it confused by reading a reference in the code as we
268  * are parsing on objcopy output of text. Use a variable for
269  * it instead.
270  */
271 static unsigned long mcount_addr = MCOUNT_ADDR;
272
273 enum {
274         FTRACE_ENABLE_CALLS             = (1 << 0),
275         FTRACE_DISABLE_CALLS            = (1 << 1),
276         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
277         FTRACE_ENABLE_MCOUNT            = (1 << 3),
278         FTRACE_DISABLE_MCOUNT           = (1 << 4),
279         FTRACE_START_FUNC_RET           = (1 << 5),
280         FTRACE_STOP_FUNC_RET            = (1 << 6),
281 };
282
283 static int ftrace_filtered;
284
285 static LIST_HEAD(ftrace_new_addrs);
286
287 static DEFINE_MUTEX(ftrace_regex_lock);
288
289 struct ftrace_page {
290         struct ftrace_page      *next;
291         unsigned long           index;
292         struct dyn_ftrace       records[];
293 };
294
295 #define ENTRIES_PER_PAGE \
296   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
297
298 /* estimate from running different kernels */
299 #define NR_TO_INIT              10000
300
301 static struct ftrace_page       *ftrace_pages_start;
302 static struct ftrace_page       *ftrace_pages;
303
304 static struct dyn_ftrace *ftrace_free_records;
305
306
307 #ifdef CONFIG_KPROBES
308
309 static int frozen_record_count;
310
311 static inline void freeze_record(struct dyn_ftrace *rec)
312 {
313         if (!(rec->flags & FTRACE_FL_FROZEN)) {
314                 rec->flags |= FTRACE_FL_FROZEN;
315                 frozen_record_count++;
316         }
317 }
318
319 static inline void unfreeze_record(struct dyn_ftrace *rec)
320 {
321         if (rec->flags & FTRACE_FL_FROZEN) {
322                 rec->flags &= ~FTRACE_FL_FROZEN;
323                 frozen_record_count--;
324         }
325 }
326
327 static inline int record_frozen(struct dyn_ftrace *rec)
328 {
329         return rec->flags & FTRACE_FL_FROZEN;
330 }
331 #else
332 # define freeze_record(rec)                     ({ 0; })
333 # define unfreeze_record(rec)                   ({ 0; })
334 # define record_frozen(rec)                     ({ 0; })
335 #endif /* CONFIG_KPROBES */
336
337 static void ftrace_free_rec(struct dyn_ftrace *rec)
338 {
339         rec->ip = (unsigned long)ftrace_free_records;
340         ftrace_free_records = rec;
341         rec->flags |= FTRACE_FL_FREE;
342 }
343
344 void ftrace_release(void *start, unsigned long size)
345 {
346         struct dyn_ftrace *rec;
347         struct ftrace_page *pg;
348         unsigned long s = (unsigned long)start;
349         unsigned long e = s + size;
350         int i;
351
352         if (ftrace_disabled || !start)
353                 return;
354
355         /* should not be called from interrupt context */
356         spin_lock(&ftrace_lock);
357
358         for (pg = ftrace_pages_start; pg; pg = pg->next) {
359                 for (i = 0; i < pg->index; i++) {
360                         rec = &pg->records[i];
361
362                         if ((rec->ip >= s) && (rec->ip < e))
363                                 ftrace_free_rec(rec);
364                 }
365         }
366         spin_unlock(&ftrace_lock);
367 }
368
369 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
370 {
371         struct dyn_ftrace *rec;
372
373         /* First check for freed records */
374         if (ftrace_free_records) {
375                 rec = ftrace_free_records;
376
377                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
378                         FTRACE_WARN_ON_ONCE(1);
379                         ftrace_free_records = NULL;
380                         return NULL;
381                 }
382
383                 ftrace_free_records = (void *)rec->ip;
384                 memset(rec, 0, sizeof(*rec));
385                 return rec;
386         }
387
388         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
389                 if (!ftrace_pages->next) {
390                         /* allocate another page */
391                         ftrace_pages->next =
392                                 (void *)get_zeroed_page(GFP_KERNEL);
393                         if (!ftrace_pages->next)
394                                 return NULL;
395                 }
396                 ftrace_pages = ftrace_pages->next;
397         }
398
399         return &ftrace_pages->records[ftrace_pages->index++];
400 }
401
402 static struct dyn_ftrace *
403 ftrace_record_ip(unsigned long ip)
404 {
405         struct dyn_ftrace *rec;
406
407         if (ftrace_disabled)
408                 return NULL;
409
410         rec = ftrace_alloc_dyn_node(ip);
411         if (!rec)
412                 return NULL;
413
414         rec->ip = ip;
415
416         list_add(&rec->list, &ftrace_new_addrs);
417
418         return rec;
419 }
420
421 static void print_ip_ins(const char *fmt, unsigned char *p)
422 {
423         int i;
424
425         printk(KERN_CONT "%s", fmt);
426
427         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
428                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
429 }
430
431 static void ftrace_bug(int failed, unsigned long ip)
432 {
433         switch (failed) {
434         case -EFAULT:
435                 FTRACE_WARN_ON_ONCE(1);
436                 pr_info("ftrace faulted on modifying ");
437                 print_ip_sym(ip);
438                 break;
439         case -EINVAL:
440                 FTRACE_WARN_ON_ONCE(1);
441                 pr_info("ftrace failed to modify ");
442                 print_ip_sym(ip);
443                 print_ip_ins(" actual: ", (unsigned char *)ip);
444                 printk(KERN_CONT "\n");
445                 break;
446         case -EPERM:
447                 FTRACE_WARN_ON_ONCE(1);
448                 pr_info("ftrace faulted on writing ");
449                 print_ip_sym(ip);
450                 break;
451         default:
452                 FTRACE_WARN_ON_ONCE(1);
453                 pr_info("ftrace faulted on unknown error ");
454                 print_ip_sym(ip);
455         }
456 }
457
458
459 static int
460 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
461 {
462         unsigned long ip, fl;
463         unsigned long ftrace_addr;
464
465         ftrace_addr = (unsigned long)ftrace_caller;
466
467         ip = rec->ip;
468
469         /*
470          * If this record is not to be traced and
471          * it is not enabled then do nothing.
472          *
473          * If this record is not to be traced and
474          * it is enabled then disabled it.
475          *
476          */
477         if (rec->flags & FTRACE_FL_NOTRACE) {
478                 if (rec->flags & FTRACE_FL_ENABLED)
479                         rec->flags &= ~FTRACE_FL_ENABLED;
480                 else
481                         return 0;
482
483         } else if (ftrace_filtered && enable) {
484                 /*
485                  * Filtering is on:
486                  */
487
488                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
489
490                 /* Record is filtered and enabled, do nothing */
491                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
492                         return 0;
493
494                 /* Record is not filtered and is not enabled do nothing */
495                 if (!fl)
496                         return 0;
497
498                 /* Record is not filtered but enabled, disable it */
499                 if (fl == FTRACE_FL_ENABLED)
500                         rec->flags &= ~FTRACE_FL_ENABLED;
501                 else
502                 /* Otherwise record is filtered but not enabled, enable it */
503                         rec->flags |= FTRACE_FL_ENABLED;
504         } else {
505                 /* Disable or not filtered */
506
507                 if (enable) {
508                         /* if record is enabled, do nothing */
509                         if (rec->flags & FTRACE_FL_ENABLED)
510                                 return 0;
511
512                         rec->flags |= FTRACE_FL_ENABLED;
513
514                 } else {
515
516                         /* if record is not enabled do nothing */
517                         if (!(rec->flags & FTRACE_FL_ENABLED))
518                                 return 0;
519
520                         rec->flags &= ~FTRACE_FL_ENABLED;
521                 }
522         }
523
524         if (rec->flags & FTRACE_FL_ENABLED)
525                 return ftrace_make_call(rec, ftrace_addr);
526         else
527                 return ftrace_make_nop(NULL, rec, ftrace_addr);
528 }
529
530 static void ftrace_replace_code(int enable)
531 {
532         int i, failed;
533         struct dyn_ftrace *rec;
534         struct ftrace_page *pg;
535
536         for (pg = ftrace_pages_start; pg; pg = pg->next) {
537                 for (i = 0; i < pg->index; i++) {
538                         rec = &pg->records[i];
539
540                         /*
541                          * Skip over free records and records that have
542                          * failed.
543                          */
544                         if (rec->flags & FTRACE_FL_FREE ||
545                             rec->flags & FTRACE_FL_FAILED)
546                                 continue;
547
548                         /* ignore updates to this record's mcount site */
549                         if (get_kprobe((void *)rec->ip)) {
550                                 freeze_record(rec);
551                                 continue;
552                         } else {
553                                 unfreeze_record(rec);
554                         }
555
556                         failed = __ftrace_replace_code(rec, enable);
557                         if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
558                                 rec->flags |= FTRACE_FL_FAILED;
559                                 if ((system_state == SYSTEM_BOOTING) ||
560                                     !core_kernel_text(rec->ip)) {
561                                         ftrace_free_rec(rec);
562                                 } else
563                                         ftrace_bug(failed, rec->ip);
564                         }
565                 }
566         }
567 }
568
569 static int
570 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
571 {
572         unsigned long ip;
573         int ret;
574
575         ip = rec->ip;
576
577         ret = ftrace_make_nop(mod, rec, mcount_addr);
578         if (ret) {
579                 ftrace_bug(ret, ip);
580                 rec->flags |= FTRACE_FL_FAILED;
581                 return 0;
582         }
583         return 1;
584 }
585
586 static int __ftrace_modify_code(void *data)
587 {
588         int *command = data;
589
590         if (*command & FTRACE_ENABLE_CALLS)
591                 ftrace_replace_code(1);
592         else if (*command & FTRACE_DISABLE_CALLS)
593                 ftrace_replace_code(0);
594
595         if (*command & FTRACE_UPDATE_TRACE_FUNC)
596                 ftrace_update_ftrace_func(ftrace_trace_function);
597
598         if (*command & FTRACE_START_FUNC_RET)
599                 ftrace_enable_ftrace_graph_caller();
600         else if (*command & FTRACE_STOP_FUNC_RET)
601                 ftrace_disable_ftrace_graph_caller();
602
603         return 0;
604 }
605
606 static void ftrace_run_update_code(int command)
607 {
608         stop_machine(__ftrace_modify_code, &command, NULL);
609 }
610
611 static ftrace_func_t saved_ftrace_func;
612 static int ftrace_start_up;
613
614 static void ftrace_startup_enable(int command)
615 {
616         if (saved_ftrace_func != ftrace_trace_function) {
617                 saved_ftrace_func = ftrace_trace_function;
618                 command |= FTRACE_UPDATE_TRACE_FUNC;
619         }
620
621         if (!command || !ftrace_enabled)
622                 return;
623
624         ftrace_run_update_code(command);
625 }
626
627 static void ftrace_startup(int command)
628 {
629         if (unlikely(ftrace_disabled))
630                 return;
631
632         mutex_lock(&ftrace_start_lock);
633         ftrace_start_up++;
634         command |= FTRACE_ENABLE_CALLS;
635
636         ftrace_startup_enable(command);
637
638         mutex_unlock(&ftrace_start_lock);
639 }
640
641 static void ftrace_shutdown(int command)
642 {
643         if (unlikely(ftrace_disabled))
644                 return;
645
646         mutex_lock(&ftrace_start_lock);
647         ftrace_start_up--;
648         if (!ftrace_start_up)
649                 command |= FTRACE_DISABLE_CALLS;
650
651         if (saved_ftrace_func != ftrace_trace_function) {
652                 saved_ftrace_func = ftrace_trace_function;
653                 command |= FTRACE_UPDATE_TRACE_FUNC;
654         }
655
656         if (!command || !ftrace_enabled)
657                 goto out;
658
659         ftrace_run_update_code(command);
660  out:
661         mutex_unlock(&ftrace_start_lock);
662 }
663
664 static void ftrace_startup_sysctl(void)
665 {
666         int command = FTRACE_ENABLE_MCOUNT;
667
668         if (unlikely(ftrace_disabled))
669                 return;
670
671         mutex_lock(&ftrace_start_lock);
672         /* Force update next time */
673         saved_ftrace_func = NULL;
674         /* ftrace_start_up is true if we want ftrace running */
675         if (ftrace_start_up)
676                 command |= FTRACE_ENABLE_CALLS;
677
678         ftrace_run_update_code(command);
679         mutex_unlock(&ftrace_start_lock);
680 }
681
682 static void ftrace_shutdown_sysctl(void)
683 {
684         int command = FTRACE_DISABLE_MCOUNT;
685
686         if (unlikely(ftrace_disabled))
687                 return;
688
689         mutex_lock(&ftrace_start_lock);
690         /* ftrace_start_up is true if ftrace is running */
691         if (ftrace_start_up)
692                 command |= FTRACE_DISABLE_CALLS;
693
694         ftrace_run_update_code(command);
695         mutex_unlock(&ftrace_start_lock);
696 }
697
698 static cycle_t          ftrace_update_time;
699 static unsigned long    ftrace_update_cnt;
700 unsigned long           ftrace_update_tot_cnt;
701
702 static int ftrace_update_code(struct module *mod)
703 {
704         struct dyn_ftrace *p, *t;
705         cycle_t start, stop;
706
707         start = ftrace_now(raw_smp_processor_id());
708         ftrace_update_cnt = 0;
709
710         list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
711
712                 /* If something went wrong, bail without enabling anything */
713                 if (unlikely(ftrace_disabled))
714                         return -1;
715
716                 list_del_init(&p->list);
717
718                 /* convert record (i.e, patch mcount-call with NOP) */
719                 if (ftrace_code_disable(mod, p)) {
720                         p->flags |= FTRACE_FL_CONVERTED;
721                         ftrace_update_cnt++;
722                 } else
723                         ftrace_free_rec(p);
724         }
725
726         stop = ftrace_now(raw_smp_processor_id());
727         ftrace_update_time = stop - start;
728         ftrace_update_tot_cnt += ftrace_update_cnt;
729
730         return 0;
731 }
732
733 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
734 {
735         struct ftrace_page *pg;
736         int cnt;
737         int i;
738
739         /* allocate a few pages */
740         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
741         if (!ftrace_pages_start)
742                 return -1;
743
744         /*
745          * Allocate a few more pages.
746          *
747          * TODO: have some parser search vmlinux before
748          *   final linking to find all calls to ftrace.
749          *   Then we can:
750          *    a) know how many pages to allocate.
751          *     and/or
752          *    b) set up the table then.
753          *
754          *  The dynamic code is still necessary for
755          *  modules.
756          */
757
758         pg = ftrace_pages = ftrace_pages_start;
759
760         cnt = num_to_init / ENTRIES_PER_PAGE;
761         pr_info("ftrace: allocating %ld entries in %d pages\n",
762                 num_to_init, cnt + 1);
763
764         for (i = 0; i < cnt; i++) {
765                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
766
767                 /* If we fail, we'll try later anyway */
768                 if (!pg->next)
769                         break;
770
771                 pg = pg->next;
772         }
773
774         return 0;
775 }
776
777 enum {
778         FTRACE_ITER_FILTER      = (1 << 0),
779         FTRACE_ITER_CONT        = (1 << 1),
780         FTRACE_ITER_NOTRACE     = (1 << 2),
781         FTRACE_ITER_FAILURES    = (1 << 3),
782 };
783
784 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
785
786 struct ftrace_iterator {
787         struct ftrace_page      *pg;
788         unsigned                idx;
789         unsigned                flags;
790         unsigned char           buffer[FTRACE_BUFF_MAX+1];
791         unsigned                buffer_idx;
792         unsigned                filtered;
793 };
794
795 static void *
796 t_next(struct seq_file *m, void *v, loff_t *pos)
797 {
798         struct ftrace_iterator *iter = m->private;
799         struct dyn_ftrace *rec = NULL;
800
801         (*pos)++;
802
803         /* should not be called from interrupt context */
804         spin_lock(&ftrace_lock);
805  retry:
806         if (iter->idx >= iter->pg->index) {
807                 if (iter->pg->next) {
808                         iter->pg = iter->pg->next;
809                         iter->idx = 0;
810                         goto retry;
811                 } else {
812                         iter->idx = -1;
813                 }
814         } else {
815                 rec = &iter->pg->records[iter->idx++];
816                 if ((rec->flags & FTRACE_FL_FREE) ||
817
818                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
819                      (rec->flags & FTRACE_FL_FAILED)) ||
820
821                     ((iter->flags & FTRACE_ITER_FAILURES) &&
822                      !(rec->flags & FTRACE_FL_FAILED)) ||
823
824                     ((iter->flags & FTRACE_ITER_FILTER) &&
825                      !(rec->flags & FTRACE_FL_FILTER)) ||
826
827                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
828                      !(rec->flags & FTRACE_FL_NOTRACE))) {
829                         rec = NULL;
830                         goto retry;
831                 }
832         }
833         spin_unlock(&ftrace_lock);
834
835         return rec;
836 }
837
838 static void *t_start(struct seq_file *m, loff_t *pos)
839 {
840         struct ftrace_iterator *iter = m->private;
841         void *p = NULL;
842
843         if (*pos > 0) {
844                 if (iter->idx < 0)
845                         return p;
846                 (*pos)--;
847                 iter->idx--;
848         }
849
850         p = t_next(m, p, pos);
851
852         return p;
853 }
854
855 static void t_stop(struct seq_file *m, void *p)
856 {
857 }
858
859 static int t_show(struct seq_file *m, void *v)
860 {
861         struct dyn_ftrace *rec = v;
862         char str[KSYM_SYMBOL_LEN];
863
864         if (!rec)
865                 return 0;
866
867         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
868
869         seq_printf(m, "%s\n", str);
870
871         return 0;
872 }
873
874 static struct seq_operations show_ftrace_seq_ops = {
875         .start = t_start,
876         .next = t_next,
877         .stop = t_stop,
878         .show = t_show,
879 };
880
881 static int
882 ftrace_avail_open(struct inode *inode, struct file *file)
883 {
884         struct ftrace_iterator *iter;
885         int ret;
886
887         if (unlikely(ftrace_disabled))
888                 return -ENODEV;
889
890         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
891         if (!iter)
892                 return -ENOMEM;
893
894         iter->pg = ftrace_pages_start;
895
896         ret = seq_open(file, &show_ftrace_seq_ops);
897         if (!ret) {
898                 struct seq_file *m = file->private_data;
899
900                 m->private = iter;
901         } else {
902                 kfree(iter);
903         }
904
905         return ret;
906 }
907
908 int ftrace_avail_release(struct inode *inode, struct file *file)
909 {
910         struct seq_file *m = (struct seq_file *)file->private_data;
911         struct ftrace_iterator *iter = m->private;
912
913         seq_release(inode, file);
914         kfree(iter);
915
916         return 0;
917 }
918
919 static int
920 ftrace_failures_open(struct inode *inode, struct file *file)
921 {
922         int ret;
923         struct seq_file *m;
924         struct ftrace_iterator *iter;
925
926         ret = ftrace_avail_open(inode, file);
927         if (!ret) {
928                 m = (struct seq_file *)file->private_data;
929                 iter = (struct ftrace_iterator *)m->private;
930                 iter->flags = FTRACE_ITER_FAILURES;
931         }
932
933         return ret;
934 }
935
936
937 static void ftrace_filter_reset(int enable)
938 {
939         struct ftrace_page *pg;
940         struct dyn_ftrace *rec;
941         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
942         unsigned i;
943
944         /* should not be called from interrupt context */
945         spin_lock(&ftrace_lock);
946         if (enable)
947                 ftrace_filtered = 0;
948         pg = ftrace_pages_start;
949         while (pg) {
950                 for (i = 0; i < pg->index; i++) {
951                         rec = &pg->records[i];
952                         if (rec->flags & FTRACE_FL_FAILED)
953                                 continue;
954                         rec->flags &= ~type;
955                 }
956                 pg = pg->next;
957         }
958         spin_unlock(&ftrace_lock);
959 }
960
961 static int
962 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
963 {
964         struct ftrace_iterator *iter;
965         int ret = 0;
966
967         if (unlikely(ftrace_disabled))
968                 return -ENODEV;
969
970         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
971         if (!iter)
972                 return -ENOMEM;
973
974         mutex_lock(&ftrace_regex_lock);
975         if ((file->f_mode & FMODE_WRITE) &&
976             !(file->f_flags & O_APPEND))
977                 ftrace_filter_reset(enable);
978
979         if (file->f_mode & FMODE_READ) {
980                 iter->pg = ftrace_pages_start;
981                 iter->flags = enable ? FTRACE_ITER_FILTER :
982                         FTRACE_ITER_NOTRACE;
983
984                 ret = seq_open(file, &show_ftrace_seq_ops);
985                 if (!ret) {
986                         struct seq_file *m = file->private_data;
987                         m->private = iter;
988                 } else
989                         kfree(iter);
990         } else
991                 file->private_data = iter;
992         mutex_unlock(&ftrace_regex_lock);
993
994         return ret;
995 }
996
997 static int
998 ftrace_filter_open(struct inode *inode, struct file *file)
999 {
1000         return ftrace_regex_open(inode, file, 1);
1001 }
1002
1003 static int
1004 ftrace_notrace_open(struct inode *inode, struct file *file)
1005 {
1006         return ftrace_regex_open(inode, file, 0);
1007 }
1008
1009 static ssize_t
1010 ftrace_regex_read(struct file *file, char __user *ubuf,
1011                        size_t cnt, loff_t *ppos)
1012 {
1013         if (file->f_mode & FMODE_READ)
1014                 return seq_read(file, ubuf, cnt, ppos);
1015         else
1016                 return -EPERM;
1017 }
1018
1019 static loff_t
1020 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1021 {
1022         loff_t ret;
1023
1024         if (file->f_mode & FMODE_READ)
1025                 ret = seq_lseek(file, offset, origin);
1026         else
1027                 file->f_pos = ret = 1;
1028
1029         return ret;
1030 }
1031
1032 enum {
1033         MATCH_FULL,
1034         MATCH_FRONT_ONLY,
1035         MATCH_MIDDLE_ONLY,
1036         MATCH_END_ONLY,
1037 };
1038
1039 static void
1040 ftrace_match(unsigned char *buff, int len, int enable)
1041 {
1042         char str[KSYM_SYMBOL_LEN];
1043         char *search = NULL;
1044         struct ftrace_page *pg;
1045         struct dyn_ftrace *rec;
1046         int type = MATCH_FULL;
1047         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1048         unsigned i, match = 0, search_len = 0;
1049
1050         for (i = 0; i < len; i++) {
1051                 if (buff[i] == '*') {
1052                         if (!i) {
1053                                 search = buff + i + 1;
1054                                 type = MATCH_END_ONLY;
1055                                 search_len = len - (i + 1);
1056                         } else {
1057                                 if (type == MATCH_END_ONLY) {
1058                                         type = MATCH_MIDDLE_ONLY;
1059                                 } else {
1060                                         match = i;
1061                                         type = MATCH_FRONT_ONLY;
1062                                 }
1063                                 buff[i] = 0;
1064                                 break;
1065                         }
1066                 }
1067         }
1068
1069         /* should not be called from interrupt context */
1070         spin_lock(&ftrace_lock);
1071         if (enable)
1072                 ftrace_filtered = 1;
1073         pg = ftrace_pages_start;
1074         while (pg) {
1075                 for (i = 0; i < pg->index; i++) {
1076                         int matched = 0;
1077                         char *ptr;
1078
1079                         rec = &pg->records[i];
1080                         if (rec->flags & FTRACE_FL_FAILED)
1081                                 continue;
1082                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1083                         switch (type) {
1084                         case MATCH_FULL:
1085                                 if (strcmp(str, buff) == 0)
1086                                         matched = 1;
1087                                 break;
1088                         case MATCH_FRONT_ONLY:
1089                                 if (memcmp(str, buff, match) == 0)
1090                                         matched = 1;
1091                                 break;
1092                         case MATCH_MIDDLE_ONLY:
1093                                 if (strstr(str, search))
1094                                         matched = 1;
1095                                 break;
1096                         case MATCH_END_ONLY:
1097                                 ptr = strstr(str, search);
1098                                 if (ptr && (ptr[search_len] == 0))
1099                                         matched = 1;
1100                                 break;
1101                         }
1102                         if (matched)
1103                                 rec->flags |= flag;
1104                 }
1105                 pg = pg->next;
1106         }
1107         spin_unlock(&ftrace_lock);
1108 }
1109
1110 static ssize_t
1111 ftrace_regex_write(struct file *file, const char __user *ubuf,
1112                    size_t cnt, loff_t *ppos, int enable)
1113 {
1114         struct ftrace_iterator *iter;
1115         char ch;
1116         size_t read = 0;
1117         ssize_t ret;
1118
1119         if (!cnt || cnt < 0)
1120                 return 0;
1121
1122         mutex_lock(&ftrace_regex_lock);
1123
1124         if (file->f_mode & FMODE_READ) {
1125                 struct seq_file *m = file->private_data;
1126                 iter = m->private;
1127         } else
1128                 iter = file->private_data;
1129
1130         if (!*ppos) {
1131                 iter->flags &= ~FTRACE_ITER_CONT;
1132                 iter->buffer_idx = 0;
1133         }
1134
1135         ret = get_user(ch, ubuf++);
1136         if (ret)
1137                 goto out;
1138         read++;
1139         cnt--;
1140
1141         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1142                 /* skip white space */
1143                 while (cnt && isspace(ch)) {
1144                         ret = get_user(ch, ubuf++);
1145                         if (ret)
1146                                 goto out;
1147                         read++;
1148                         cnt--;
1149                 }
1150
1151                 if (isspace(ch)) {
1152                         file->f_pos += read;
1153                         ret = read;
1154                         goto out;
1155                 }
1156
1157                 iter->buffer_idx = 0;
1158         }
1159
1160         while (cnt && !isspace(ch)) {
1161                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1162                         iter->buffer[iter->buffer_idx++] = ch;
1163                 else {
1164                         ret = -EINVAL;
1165                         goto out;
1166                 }
1167                 ret = get_user(ch, ubuf++);
1168                 if (ret)
1169                         goto out;
1170                 read++;
1171                 cnt--;
1172         }
1173
1174         if (isspace(ch)) {
1175                 iter->filtered++;
1176                 iter->buffer[iter->buffer_idx] = 0;
1177                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1178                 iter->buffer_idx = 0;
1179         } else
1180                 iter->flags |= FTRACE_ITER_CONT;
1181
1182
1183         file->f_pos += read;
1184
1185         ret = read;
1186  out:
1187         mutex_unlock(&ftrace_regex_lock);
1188
1189         return ret;
1190 }
1191
1192 static ssize_t
1193 ftrace_filter_write(struct file *file, const char __user *ubuf,
1194                     size_t cnt, loff_t *ppos)
1195 {
1196         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1197 }
1198
1199 static ssize_t
1200 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1201                      size_t cnt, loff_t *ppos)
1202 {
1203         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1204 }
1205
1206 static void
1207 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1208 {
1209         if (unlikely(ftrace_disabled))
1210                 return;
1211
1212         mutex_lock(&ftrace_regex_lock);
1213         if (reset)
1214                 ftrace_filter_reset(enable);
1215         if (buf)
1216                 ftrace_match(buf, len, enable);
1217         mutex_unlock(&ftrace_regex_lock);
1218 }
1219
1220 /**
1221  * ftrace_set_filter - set a function to filter on in ftrace
1222  * @buf - the string that holds the function filter text.
1223  * @len - the length of the string.
1224  * @reset - non zero to reset all filters before applying this filter.
1225  *
1226  * Filters denote which functions should be enabled when tracing is enabled.
1227  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1228  */
1229 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1230 {
1231         ftrace_set_regex(buf, len, reset, 1);
1232 }
1233
1234 /**
1235  * ftrace_set_notrace - set a function to not trace in ftrace
1236  * @buf - the string that holds the function notrace text.
1237  * @len - the length of the string.
1238  * @reset - non zero to reset all filters before applying this filter.
1239  *
1240  * Notrace Filters denote which functions should not be enabled when tracing
1241  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1242  * for tracing.
1243  */
1244 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1245 {
1246         ftrace_set_regex(buf, len, reset, 0);
1247 }
1248
1249 static int
1250 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1251 {
1252         struct seq_file *m = (struct seq_file *)file->private_data;
1253         struct ftrace_iterator *iter;
1254
1255         mutex_lock(&ftrace_regex_lock);
1256         if (file->f_mode & FMODE_READ) {
1257                 iter = m->private;
1258
1259                 seq_release(inode, file);
1260         } else
1261                 iter = file->private_data;
1262
1263         if (iter->buffer_idx) {
1264                 iter->filtered++;
1265                 iter->buffer[iter->buffer_idx] = 0;
1266                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1267         }
1268
1269         mutex_lock(&ftrace_sysctl_lock);
1270         mutex_lock(&ftrace_start_lock);
1271         if (ftrace_start_up && ftrace_enabled)
1272                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1273         mutex_unlock(&ftrace_start_lock);
1274         mutex_unlock(&ftrace_sysctl_lock);
1275
1276         kfree(iter);
1277         mutex_unlock(&ftrace_regex_lock);
1278         return 0;
1279 }
1280
1281 static int
1282 ftrace_filter_release(struct inode *inode, struct file *file)
1283 {
1284         return ftrace_regex_release(inode, file, 1);
1285 }
1286
1287 static int
1288 ftrace_notrace_release(struct inode *inode, struct file *file)
1289 {
1290         return ftrace_regex_release(inode, file, 0);
1291 }
1292
1293 static struct file_operations ftrace_avail_fops = {
1294         .open = ftrace_avail_open,
1295         .read = seq_read,
1296         .llseek = seq_lseek,
1297         .release = ftrace_avail_release,
1298 };
1299
1300 static struct file_operations ftrace_failures_fops = {
1301         .open = ftrace_failures_open,
1302         .read = seq_read,
1303         .llseek = seq_lseek,
1304         .release = ftrace_avail_release,
1305 };
1306
1307 static struct file_operations ftrace_filter_fops = {
1308         .open = ftrace_filter_open,
1309         .read = ftrace_regex_read,
1310         .write = ftrace_filter_write,
1311         .llseek = ftrace_regex_lseek,
1312         .release = ftrace_filter_release,
1313 };
1314
1315 static struct file_operations ftrace_notrace_fops = {
1316         .open = ftrace_notrace_open,
1317         .read = ftrace_regex_read,
1318         .write = ftrace_notrace_write,
1319         .llseek = ftrace_regex_lseek,
1320         .release = ftrace_notrace_release,
1321 };
1322
1323 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1324
1325 static DEFINE_MUTEX(graph_lock);
1326
1327 int ftrace_graph_count;
1328 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
1329
1330 static void *
1331 g_next(struct seq_file *m, void *v, loff_t *pos)
1332 {
1333         unsigned long *array = m->private;
1334         int index = *pos;
1335
1336         (*pos)++;
1337
1338         if (index >= ftrace_graph_count)
1339                 return NULL;
1340
1341         return &array[index];
1342 }
1343
1344 static void *g_start(struct seq_file *m, loff_t *pos)
1345 {
1346         void *p = NULL;
1347
1348         mutex_lock(&graph_lock);
1349
1350         p = g_next(m, p, pos);
1351
1352         return p;
1353 }
1354
1355 static void g_stop(struct seq_file *m, void *p)
1356 {
1357         mutex_unlock(&graph_lock);
1358 }
1359
1360 static int g_show(struct seq_file *m, void *v)
1361 {
1362         unsigned long *ptr = v;
1363         char str[KSYM_SYMBOL_LEN];
1364
1365         if (!ptr)
1366                 return 0;
1367
1368         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
1369
1370         seq_printf(m, "%s\n", str);
1371
1372         return 0;
1373 }
1374
1375 static struct seq_operations ftrace_graph_seq_ops = {
1376         .start = g_start,
1377         .next = g_next,
1378         .stop = g_stop,
1379         .show = g_show,
1380 };
1381
1382 static int
1383 ftrace_graph_open(struct inode *inode, struct file *file)
1384 {
1385         int ret = 0;
1386
1387         if (unlikely(ftrace_disabled))
1388                 return -ENODEV;
1389
1390         mutex_lock(&graph_lock);
1391         if ((file->f_mode & FMODE_WRITE) &&
1392             !(file->f_flags & O_APPEND)) {
1393                 ftrace_graph_count = 0;
1394                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
1395         }
1396
1397         if (file->f_mode & FMODE_READ) {
1398                 ret = seq_open(file, &ftrace_graph_seq_ops);
1399                 if (!ret) {
1400                         struct seq_file *m = file->private_data;
1401                         m->private = ftrace_graph_funcs;
1402                 }
1403         } else
1404                 file->private_data = ftrace_graph_funcs;
1405         mutex_unlock(&graph_lock);
1406
1407         return ret;
1408 }
1409
1410 static ssize_t
1411 ftrace_graph_read(struct file *file, char __user *ubuf,
1412                        size_t cnt, loff_t *ppos)
1413 {
1414         if (file->f_mode & FMODE_READ)
1415                 return seq_read(file, ubuf, cnt, ppos);
1416         else
1417                 return -EPERM;
1418 }
1419
1420 static int
1421 ftrace_set_func(unsigned long *array, int idx, char *buffer)
1422 {
1423         char str[KSYM_SYMBOL_LEN];
1424         struct dyn_ftrace *rec;
1425         struct ftrace_page *pg;
1426         int found = 0;
1427         int i;
1428
1429         if (ftrace_disabled)
1430                 return -ENODEV;
1431
1432         /* should not be called from interrupt context */
1433         spin_lock(&ftrace_lock);
1434
1435         for (pg = ftrace_pages_start; pg; pg = pg->next) {
1436                 for (i = 0; i < pg->index; i++) {
1437                         rec = &pg->records[i];
1438
1439                         if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
1440                                 continue;
1441
1442                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1443                         if (strcmp(str, buffer) == 0) {
1444                                 found = 1;
1445                                 array[idx] = rec->ip;
1446                                 break;
1447                         }
1448                 }
1449         }
1450         spin_unlock(&ftrace_lock);
1451
1452         return found ? 0 : -EINVAL;
1453 }
1454
1455 static ssize_t
1456 ftrace_graph_write(struct file *file, const char __user *ubuf,
1457                    size_t cnt, loff_t *ppos)
1458 {
1459         unsigned char buffer[FTRACE_BUFF_MAX+1];
1460         unsigned long *array;
1461         size_t read = 0;
1462         ssize_t ret;
1463         int index = 0;
1464         char ch;
1465
1466         if (!cnt || cnt < 0)
1467                 return 0;
1468
1469         mutex_lock(&graph_lock);
1470
1471         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
1472                 ret = -EBUSY;
1473                 goto out;
1474         }
1475
1476         if (file->f_mode & FMODE_READ) {
1477                 struct seq_file *m = file->private_data;
1478                 array = m->private;
1479         } else
1480                 array = file->private_data;
1481
1482         ret = get_user(ch, ubuf++);
1483         if (ret)
1484                 goto out;
1485         read++;
1486         cnt--;
1487
1488         /* skip white space */
1489         while (cnt && isspace(ch)) {
1490                 ret = get_user(ch, ubuf++);
1491                 if (ret)
1492                         goto out;
1493                 read++;
1494                 cnt--;
1495         }
1496
1497         if (isspace(ch)) {
1498                 *ppos += read;
1499                 ret = read;
1500                 goto out;
1501         }
1502
1503         while (cnt && !isspace(ch)) {
1504                 if (index < FTRACE_BUFF_MAX)
1505                         buffer[index++] = ch;
1506                 else {
1507                         ret = -EINVAL;
1508                         goto out;
1509                 }
1510                 ret = get_user(ch, ubuf++);
1511                 if (ret)
1512                         goto out;
1513                 read++;
1514                 cnt--;
1515         }
1516         buffer[index] = 0;
1517
1518         /* we allow only one at a time */
1519         ret = ftrace_set_func(array, ftrace_graph_count, buffer);
1520         if (ret)
1521                 goto out;
1522
1523         ftrace_graph_count++;
1524
1525         file->f_pos += read;
1526
1527         ret = read;
1528  out:
1529         mutex_unlock(&graph_lock);
1530
1531         return ret;
1532 }
1533
1534 static const struct file_operations ftrace_graph_fops = {
1535         .open = ftrace_graph_open,
1536         .read = ftrace_graph_read,
1537         .write = ftrace_graph_write,
1538 };
1539 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1540
1541 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
1542 {
1543         struct dentry *entry;
1544
1545         entry = debugfs_create_file("available_filter_functions", 0444,
1546                                     d_tracer, NULL, &ftrace_avail_fops);
1547         if (!entry)
1548                 pr_warning("Could not create debugfs "
1549                            "'available_filter_functions' entry\n");
1550
1551         entry = debugfs_create_file("failures", 0444,
1552                                     d_tracer, NULL, &ftrace_failures_fops);
1553         if (!entry)
1554                 pr_warning("Could not create debugfs 'failures' entry\n");
1555
1556         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1557                                     NULL, &ftrace_filter_fops);
1558         if (!entry)
1559                 pr_warning("Could not create debugfs "
1560                            "'set_ftrace_filter' entry\n");
1561
1562         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1563                                     NULL, &ftrace_notrace_fops);
1564         if (!entry)
1565                 pr_warning("Could not create debugfs "
1566                            "'set_ftrace_notrace' entry\n");
1567
1568 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1569         entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
1570                                     NULL,
1571                                     &ftrace_graph_fops);
1572         if (!entry)
1573                 pr_warning("Could not create debugfs "
1574                            "'set_graph_function' entry\n");
1575 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1576
1577         return 0;
1578 }
1579
1580 static int ftrace_convert_nops(struct module *mod,
1581                                unsigned long *start,
1582                                unsigned long *end)
1583 {
1584         unsigned long *p;
1585         unsigned long addr;
1586         unsigned long flags;
1587
1588         mutex_lock(&ftrace_start_lock);
1589         p = start;
1590         while (p < end) {
1591                 addr = ftrace_call_adjust(*p++);
1592                 /*
1593                  * Some architecture linkers will pad between
1594                  * the different mcount_loc sections of different
1595                  * object files to satisfy alignments.
1596                  * Skip any NULL pointers.
1597                  */
1598                 if (!addr)
1599                         continue;
1600                 ftrace_record_ip(addr);
1601         }
1602
1603         /* disable interrupts to prevent kstop machine */
1604         local_irq_save(flags);
1605         ftrace_update_code(mod);
1606         local_irq_restore(flags);
1607         mutex_unlock(&ftrace_start_lock);
1608
1609         return 0;
1610 }
1611
1612 void ftrace_init_module(struct module *mod,
1613                         unsigned long *start, unsigned long *end)
1614 {
1615         if (ftrace_disabled || start == end)
1616                 return;
1617         ftrace_convert_nops(mod, start, end);
1618 }
1619
1620 extern unsigned long __start_mcount_loc[];
1621 extern unsigned long __stop_mcount_loc[];
1622
1623 void __init ftrace_init(void)
1624 {
1625         unsigned long count, addr, flags;
1626         int ret;
1627
1628         /* Keep the ftrace pointer to the stub */
1629         addr = (unsigned long)ftrace_stub;
1630
1631         local_irq_save(flags);
1632         ftrace_dyn_arch_init(&addr);
1633         local_irq_restore(flags);
1634
1635         /* ftrace_dyn_arch_init places the return code in addr */
1636         if (addr)
1637                 goto failed;
1638
1639         count = __stop_mcount_loc - __start_mcount_loc;
1640
1641         ret = ftrace_dyn_table_alloc(count);
1642         if (ret)
1643                 goto failed;
1644
1645         last_ftrace_enabled = ftrace_enabled = 1;
1646
1647         ret = ftrace_convert_nops(NULL,
1648                                   __start_mcount_loc,
1649                                   __stop_mcount_loc);
1650
1651         return;
1652  failed:
1653         ftrace_disabled = 1;
1654 }
1655
1656 #else
1657
1658 static int __init ftrace_nodyn_init(void)
1659 {
1660         ftrace_enabled = 1;
1661         return 0;
1662 }
1663 device_initcall(ftrace_nodyn_init);
1664
1665 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
1666 static inline void ftrace_startup_enable(int command) { }
1667 /* Keep as macros so we do not need to define the commands */
1668 # define ftrace_startup(command)        do { } while (0)
1669 # define ftrace_shutdown(command)       do { } while (0)
1670 # define ftrace_startup_sysctl()        do { } while (0)
1671 # define ftrace_shutdown_sysctl()       do { } while (0)
1672 #endif /* CONFIG_DYNAMIC_FTRACE */
1673
1674 static ssize_t
1675 ftrace_pid_read(struct file *file, char __user *ubuf,
1676                        size_t cnt, loff_t *ppos)
1677 {
1678         char buf[64];
1679         int r;
1680
1681         if (ftrace_pid_trace >= 0)
1682                 r = sprintf(buf, "%u\n", ftrace_pid_trace);
1683         else
1684                 r = sprintf(buf, "no pid\n");
1685
1686         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1687 }
1688
1689 static ssize_t
1690 ftrace_pid_write(struct file *filp, const char __user *ubuf,
1691                    size_t cnt, loff_t *ppos)
1692 {
1693         char buf[64];
1694         long val;
1695         int ret;
1696
1697         if (cnt >= sizeof(buf))
1698                 return -EINVAL;
1699
1700         if (copy_from_user(&buf, ubuf, cnt))
1701                 return -EFAULT;
1702
1703         buf[cnt] = 0;
1704
1705         ret = strict_strtol(buf, 10, &val);
1706         if (ret < 0)
1707                 return ret;
1708
1709         mutex_lock(&ftrace_start_lock);
1710         if (ret < 0) {
1711                 /* disable pid tracing */
1712                 if (ftrace_pid_trace < 0)
1713                         goto out;
1714                 ftrace_pid_trace = -1;
1715
1716         } else {
1717
1718                 if (ftrace_pid_trace == val)
1719                         goto out;
1720
1721                 ftrace_pid_trace = val;
1722         }
1723
1724         /* update the function call */
1725         ftrace_update_pid_func();
1726         ftrace_startup_enable(0);
1727
1728  out:
1729         mutex_unlock(&ftrace_start_lock);
1730
1731         return cnt;
1732 }
1733
1734 static struct file_operations ftrace_pid_fops = {
1735         .read = ftrace_pid_read,
1736         .write = ftrace_pid_write,
1737 };
1738
1739 static __init int ftrace_init_debugfs(void)
1740 {
1741         struct dentry *d_tracer;
1742         struct dentry *entry;
1743
1744         d_tracer = tracing_init_dentry();
1745         if (!d_tracer)
1746                 return 0;
1747
1748         ftrace_init_dyn_debugfs(d_tracer);
1749
1750         entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
1751                                     NULL, &ftrace_pid_fops);
1752         if (!entry)
1753                 pr_warning("Could not create debugfs "
1754                            "'set_ftrace_pid' entry\n");
1755         return 0;
1756 }
1757
1758 fs_initcall(ftrace_init_debugfs);
1759
1760 /**
1761  * ftrace_kill - kill ftrace
1762  *
1763  * This function should be used by panic code. It stops ftrace
1764  * but in a not so nice way. If you need to simply kill ftrace
1765  * from a non-atomic section, use ftrace_kill.
1766  */
1767 void ftrace_kill(void)
1768 {
1769         ftrace_disabled = 1;
1770         ftrace_enabled = 0;
1771         clear_ftrace_function();
1772 }
1773
1774 /**
1775  * register_ftrace_function - register a function for profiling
1776  * @ops - ops structure that holds the function for profiling.
1777  *
1778  * Register a function to be called by all functions in the
1779  * kernel.
1780  *
1781  * Note: @ops->func and all the functions it calls must be labeled
1782  *       with "notrace", otherwise it will go into a
1783  *       recursive loop.
1784  */
1785 int register_ftrace_function(struct ftrace_ops *ops)
1786 {
1787         int ret;
1788
1789         if (unlikely(ftrace_disabled))
1790                 return -1;
1791
1792         mutex_lock(&ftrace_sysctl_lock);
1793
1794         ret = __register_ftrace_function(ops);
1795         ftrace_startup(0);
1796
1797         mutex_unlock(&ftrace_sysctl_lock);
1798         return ret;
1799 }
1800
1801 /**
1802  * unregister_ftrace_function - unresgister a function for profiling.
1803  * @ops - ops structure that holds the function to unregister
1804  *
1805  * Unregister a function that was added to be called by ftrace profiling.
1806  */
1807 int unregister_ftrace_function(struct ftrace_ops *ops)
1808 {
1809         int ret;
1810
1811         mutex_lock(&ftrace_sysctl_lock);
1812         ret = __unregister_ftrace_function(ops);
1813         ftrace_shutdown(0);
1814         mutex_unlock(&ftrace_sysctl_lock);
1815
1816         return ret;
1817 }
1818
1819 int
1820 ftrace_enable_sysctl(struct ctl_table *table, int write,
1821                      struct file *file, void __user *buffer, size_t *lenp,
1822                      loff_t *ppos)
1823 {
1824         int ret;
1825
1826         if (unlikely(ftrace_disabled))
1827                 return -ENODEV;
1828
1829         mutex_lock(&ftrace_sysctl_lock);
1830
1831         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1832
1833         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1834                 goto out;
1835
1836         last_ftrace_enabled = ftrace_enabled;
1837
1838         if (ftrace_enabled) {
1839
1840                 ftrace_startup_sysctl();
1841
1842                 /* we are starting ftrace again */
1843                 if (ftrace_list != &ftrace_list_end) {
1844                         if (ftrace_list->next == &ftrace_list_end)
1845                                 ftrace_trace_function = ftrace_list->func;
1846                         else
1847                                 ftrace_trace_function = ftrace_list_func;
1848                 }
1849
1850         } else {
1851                 /* stopping ftrace calls (just send to ftrace_stub) */
1852                 ftrace_trace_function = ftrace_stub;
1853
1854                 ftrace_shutdown_sysctl();
1855         }
1856
1857  out:
1858         mutex_unlock(&ftrace_sysctl_lock);
1859         return ret;
1860 }
1861
1862 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1863
1864 static atomic_t ftrace_graph_active;
1865
1866 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
1867 {
1868         return 0;
1869 }
1870
1871 /* The callbacks that hook a function */
1872 trace_func_graph_ret_t ftrace_graph_return =
1873                         (trace_func_graph_ret_t)ftrace_stub;
1874 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
1875
1876 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
1877 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
1878 {
1879         int i;
1880         int ret = 0;
1881         unsigned long flags;
1882         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
1883         struct task_struct *g, *t;
1884
1885         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
1886                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
1887                                         * sizeof(struct ftrace_ret_stack),
1888                                         GFP_KERNEL);
1889                 if (!ret_stack_list[i]) {
1890                         start = 0;
1891                         end = i;
1892                         ret = -ENOMEM;
1893                         goto free;
1894                 }
1895         }
1896
1897         read_lock_irqsave(&tasklist_lock, flags);
1898         do_each_thread(g, t) {
1899                 if (start == end) {
1900                         ret = -EAGAIN;
1901                         goto unlock;
1902                 }
1903
1904                 if (t->ret_stack == NULL) {
1905                         t->curr_ret_stack = -1;
1906                         /* Make sure IRQs see the -1 first: */
1907                         barrier();
1908                         t->ret_stack = ret_stack_list[start++];
1909                         atomic_set(&t->trace_overrun, 0);
1910                 }
1911         } while_each_thread(g, t);
1912
1913 unlock:
1914         read_unlock_irqrestore(&tasklist_lock, flags);
1915 free:
1916         for (i = start; i < end; i++)
1917                 kfree(ret_stack_list[i]);
1918         return ret;
1919 }
1920
1921 /* Allocate a return stack for each task */
1922 static int start_graph_tracing(void)
1923 {
1924         struct ftrace_ret_stack **ret_stack_list;
1925         int ret;
1926
1927         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
1928                                 sizeof(struct ftrace_ret_stack *),
1929                                 GFP_KERNEL);
1930
1931         if (!ret_stack_list)
1932                 return -ENOMEM;
1933
1934         do {
1935                 ret = alloc_retstack_tasklist(ret_stack_list);
1936         } while (ret == -EAGAIN);
1937
1938         kfree(ret_stack_list);
1939         return ret;
1940 }
1941
1942 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
1943                         trace_func_graph_ent_t entryfunc)
1944 {
1945         int ret = 0;
1946
1947         mutex_lock(&ftrace_sysctl_lock);
1948
1949         atomic_inc(&ftrace_graph_active);
1950         ret = start_graph_tracing();
1951         if (ret) {
1952                 atomic_dec(&ftrace_graph_active);
1953                 goto out;
1954         }
1955
1956         ftrace_graph_return = retfunc;
1957         ftrace_graph_entry = entryfunc;
1958
1959         ftrace_startup(FTRACE_START_FUNC_RET);
1960
1961 out:
1962         mutex_unlock(&ftrace_sysctl_lock);
1963         return ret;
1964 }
1965
1966 void unregister_ftrace_graph(void)
1967 {
1968         mutex_lock(&ftrace_sysctl_lock);
1969
1970         atomic_dec(&ftrace_graph_active);
1971         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
1972         ftrace_graph_entry = ftrace_graph_entry_stub;
1973         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
1974
1975         mutex_unlock(&ftrace_sysctl_lock);
1976 }
1977
1978 /* Allocate a return stack for newly created task */
1979 void ftrace_graph_init_task(struct task_struct *t)
1980 {
1981         if (atomic_read(&ftrace_graph_active)) {
1982                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
1983                                 * sizeof(struct ftrace_ret_stack),
1984                                 GFP_KERNEL);
1985                 if (!t->ret_stack)
1986                         return;
1987                 t->curr_ret_stack = -1;
1988                 atomic_set(&t->trace_overrun, 0);
1989         } else
1990                 t->ret_stack = NULL;
1991 }
1992
1993 void ftrace_graph_exit_task(struct task_struct *t)
1994 {
1995         struct ftrace_ret_stack *ret_stack = t->ret_stack;
1996
1997         t->ret_stack = NULL;
1998         /* NULL must become visible to IRQs before we free it: */
1999         barrier();
2000
2001         kfree(ret_stack);
2002 }
2003
2004 void ftrace_graph_stop(void)
2005 {
2006         ftrace_stop();
2007 }
2008 #endif
2009