32837e19e3bdb66535650af0ba8e3597d48a11e8
[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/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/ftrace.h>
36 #include <asm/setup.h>
37
38 #include "trace_output.h"
39 #include "trace_stat.h"
40
41 #define FTRACE_WARN_ON(cond)                    \
42         do {                                    \
43                 if (WARN_ON(cond))              \
44                         ftrace_kill();          \
45         } while (0)
46
47 #define FTRACE_WARN_ON_ONCE(cond)               \
48         do {                                    \
49                 if (WARN_ON_ONCE(cond))         \
50                         ftrace_kill();          \
51         } while (0)
52
53 /* hash bits for specific function selection */
54 #define FTRACE_HASH_BITS 7
55 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
56
57 /* ftrace_enabled is a method to turn ftrace on or off */
58 int ftrace_enabled __read_mostly;
59 static int last_ftrace_enabled;
60
61 /* Quick disabling of function tracer. */
62 int function_trace_stop;
63
64 /* List for set_ftrace_pid's pids. */
65 LIST_HEAD(ftrace_pids);
66 struct ftrace_pid {
67         struct list_head list;
68         struct pid *pid;
69 };
70
71 /*
72  * ftrace_disabled is set when an anomaly is discovered.
73  * ftrace_disabled is much stronger than ftrace_enabled.
74  */
75 static int ftrace_disabled __read_mostly;
76
77 static DEFINE_MUTEX(ftrace_lock);
78
79 static struct ftrace_ops ftrace_list_end __read_mostly =
80 {
81         .func           = ftrace_stub,
82 };
83
84 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
85 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
86 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
87 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
88
89 /*
90  * Traverse the ftrace_list, invoking all entries.  The reason that we
91  * can use rcu_dereference_raw() is that elements removed from this list
92  * are simply leaked, so there is no need to interact with a grace-period
93  * mechanism.  The rcu_dereference_raw() calls are needed to handle
94  * concurrent insertions into the ftrace_list.
95  *
96  * Silly Alpha and silly pointer-speculation compiler optimizations!
97  */
98 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
99 {
100         struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
101
102         while (op != &ftrace_list_end) {
103                 op->func(ip, parent_ip);
104                 op = rcu_dereference_raw(op->next); /*see above*/
105         };
106 }
107
108 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
109 {
110         if (!test_tsk_trace_trace(current))
111                 return;
112
113         ftrace_pid_function(ip, parent_ip);
114 }
115
116 static void set_ftrace_pid_function(ftrace_func_t func)
117 {
118         /* do not set ftrace_pid_function to itself! */
119         if (func != ftrace_pid_func)
120                 ftrace_pid_function = func;
121 }
122
123 /**
124  * clear_ftrace_function - reset the ftrace function
125  *
126  * This NULLs the ftrace function and in essence stops
127  * tracing.  There may be lag
128  */
129 void clear_ftrace_function(void)
130 {
131         ftrace_trace_function = ftrace_stub;
132         __ftrace_trace_function = ftrace_stub;
133         ftrace_pid_function = ftrace_stub;
134 }
135
136 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
137 /*
138  * For those archs that do not test ftrace_trace_stop in their
139  * mcount call site, we need to do it from C.
140  */
141 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
142 {
143         if (function_trace_stop)
144                 return;
145
146         __ftrace_trace_function(ip, parent_ip);
147 }
148 #endif
149
150 static int __register_ftrace_function(struct ftrace_ops *ops)
151 {
152         ops->next = ftrace_list;
153         /*
154          * We are entering ops into the ftrace_list but another
155          * CPU might be walking that list. We need to make sure
156          * the ops->next pointer is valid before another CPU sees
157          * the ops pointer included into the ftrace_list.
158          */
159         rcu_assign_pointer(ftrace_list, ops);
160
161         if (ftrace_enabled) {
162                 ftrace_func_t func;
163
164                 if (ops->next == &ftrace_list_end)
165                         func = ops->func;
166                 else
167                         func = ftrace_list_func;
168
169                 if (!list_empty(&ftrace_pids)) {
170                         set_ftrace_pid_function(func);
171                         func = ftrace_pid_func;
172                 }
173
174                 /*
175                  * For one func, simply call it directly.
176                  * For more than one func, call the chain.
177                  */
178 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
179                 ftrace_trace_function = func;
180 #else
181                 __ftrace_trace_function = func;
182                 ftrace_trace_function = ftrace_test_stop_func;
183 #endif
184         }
185
186         return 0;
187 }
188
189 static int __unregister_ftrace_function(struct ftrace_ops *ops)
190 {
191         struct ftrace_ops **p;
192
193         /*
194          * If we are removing the last function, then simply point
195          * to the ftrace_stub.
196          */
197         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
198                 ftrace_trace_function = ftrace_stub;
199                 ftrace_list = &ftrace_list_end;
200                 return 0;
201         }
202
203         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
204                 if (*p == ops)
205                         break;
206
207         if (*p != ops)
208                 return -1;
209
210         *p = (*p)->next;
211
212         if (ftrace_enabled) {
213                 /* If we only have one func left, then call that directly */
214                 if (ftrace_list->next == &ftrace_list_end) {
215                         ftrace_func_t func = ftrace_list->func;
216
217                         if (!list_empty(&ftrace_pids)) {
218                                 set_ftrace_pid_function(func);
219                                 func = ftrace_pid_func;
220                         }
221 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
222                         ftrace_trace_function = func;
223 #else
224                         __ftrace_trace_function = func;
225 #endif
226                 }
227         }
228
229         return 0;
230 }
231
232 static void ftrace_update_pid_func(void)
233 {
234         ftrace_func_t func;
235
236         if (ftrace_trace_function == ftrace_stub)
237                 return;
238
239 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
240         func = ftrace_trace_function;
241 #else
242         func = __ftrace_trace_function;
243 #endif
244
245         if (!list_empty(&ftrace_pids)) {
246                 set_ftrace_pid_function(func);
247                 func = ftrace_pid_func;
248         } else {
249                 if (func == ftrace_pid_func)
250                         func = ftrace_pid_function;
251         }
252
253 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
254         ftrace_trace_function = func;
255 #else
256         __ftrace_trace_function = func;
257 #endif
258 }
259
260 #ifdef CONFIG_FUNCTION_PROFILER
261 struct ftrace_profile {
262         struct hlist_node               node;
263         unsigned long                   ip;
264         unsigned long                   counter;
265 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
266         unsigned long long              time;
267         unsigned long long              time_squared;
268 #endif
269 };
270
271 struct ftrace_profile_page {
272         struct ftrace_profile_page      *next;
273         unsigned long                   index;
274         struct ftrace_profile           records[];
275 };
276
277 struct ftrace_profile_stat {
278         atomic_t                        disabled;
279         struct hlist_head               *hash;
280         struct ftrace_profile_page      *pages;
281         struct ftrace_profile_page      *start;
282         struct tracer_stat              stat;
283 };
284
285 #define PROFILE_RECORDS_SIZE                                            \
286         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
287
288 #define PROFILES_PER_PAGE                                       \
289         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
290
291 static int ftrace_profile_bits __read_mostly;
292 static int ftrace_profile_enabled __read_mostly;
293
294 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
295 static DEFINE_MUTEX(ftrace_profile_lock);
296
297 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
298
299 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
300
301 static void *
302 function_stat_next(void *v, int idx)
303 {
304         struct ftrace_profile *rec = v;
305         struct ftrace_profile_page *pg;
306
307         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
308
309  again:
310         if (idx != 0)
311                 rec++;
312
313         if ((void *)rec >= (void *)&pg->records[pg->index]) {
314                 pg = pg->next;
315                 if (!pg)
316                         return NULL;
317                 rec = &pg->records[0];
318                 if (!rec->counter)
319                         goto again;
320         }
321
322         return rec;
323 }
324
325 static void *function_stat_start(struct tracer_stat *trace)
326 {
327         struct ftrace_profile_stat *stat =
328                 container_of(trace, struct ftrace_profile_stat, stat);
329
330         if (!stat || !stat->start)
331                 return NULL;
332
333         return function_stat_next(&stat->start->records[0], 0);
334 }
335
336 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
337 /* function graph compares on total time */
338 static int function_stat_cmp(void *p1, void *p2)
339 {
340         struct ftrace_profile *a = p1;
341         struct ftrace_profile *b = p2;
342
343         if (a->time < b->time)
344                 return -1;
345         if (a->time > b->time)
346                 return 1;
347         else
348                 return 0;
349 }
350 #else
351 /* not function graph compares against hits */
352 static int function_stat_cmp(void *p1, void *p2)
353 {
354         struct ftrace_profile *a = p1;
355         struct ftrace_profile *b = p2;
356
357         if (a->counter < b->counter)
358                 return -1;
359         if (a->counter > b->counter)
360                 return 1;
361         else
362                 return 0;
363 }
364 #endif
365
366 static int function_stat_headers(struct seq_file *m)
367 {
368 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
369         seq_printf(m, "  Function                               "
370                    "Hit    Time            Avg             s^2\n"
371                       "  --------                               "
372                    "---    ----            ---             ---\n");
373 #else
374         seq_printf(m, "  Function                               Hit\n"
375                       "  --------                               ---\n");
376 #endif
377         return 0;
378 }
379
380 static int function_stat_show(struct seq_file *m, void *v)
381 {
382         struct ftrace_profile *rec = v;
383         char str[KSYM_SYMBOL_LEN];
384 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
385         static DEFINE_MUTEX(mutex);
386         static struct trace_seq s;
387         unsigned long long avg;
388         unsigned long long stddev;
389 #endif
390
391         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
392         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
393
394 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
395         seq_printf(m, "    ");
396         avg = rec->time;
397         do_div(avg, rec->counter);
398
399         /* Sample standard deviation (s^2) */
400         if (rec->counter <= 1)
401                 stddev = 0;
402         else {
403                 stddev = rec->time_squared - rec->counter * avg * avg;
404                 /*
405                  * Divide only 1000 for ns^2 -> us^2 conversion.
406                  * trace_print_graph_duration will divide 1000 again.
407                  */
408                 do_div(stddev, (rec->counter - 1) * 1000);
409         }
410
411         mutex_lock(&mutex);
412         trace_seq_init(&s);
413         trace_print_graph_duration(rec->time, &s);
414         trace_seq_puts(&s, "    ");
415         trace_print_graph_duration(avg, &s);
416         trace_seq_puts(&s, "    ");
417         trace_print_graph_duration(stddev, &s);
418         trace_print_seq(m, &s);
419         mutex_unlock(&mutex);
420 #endif
421         seq_putc(m, '\n');
422
423         return 0;
424 }
425
426 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
427 {
428         struct ftrace_profile_page *pg;
429
430         pg = stat->pages = stat->start;
431
432         while (pg) {
433                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
434                 pg->index = 0;
435                 pg = pg->next;
436         }
437
438         memset(stat->hash, 0,
439                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
440 }
441
442 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
443 {
444         struct ftrace_profile_page *pg;
445         int functions;
446         int pages;
447         int i;
448
449         /* If we already allocated, do nothing */
450         if (stat->pages)
451                 return 0;
452
453         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
454         if (!stat->pages)
455                 return -ENOMEM;
456
457 #ifdef CONFIG_DYNAMIC_FTRACE
458         functions = ftrace_update_tot_cnt;
459 #else
460         /*
461          * We do not know the number of functions that exist because
462          * dynamic tracing is what counts them. With past experience
463          * we have around 20K functions. That should be more than enough.
464          * It is highly unlikely we will execute every function in
465          * the kernel.
466          */
467         functions = 20000;
468 #endif
469
470         pg = stat->start = stat->pages;
471
472         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
473
474         for (i = 0; i < pages; i++) {
475                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
476                 if (!pg->next)
477                         goto out_free;
478                 pg = pg->next;
479         }
480
481         return 0;
482
483  out_free:
484         pg = stat->start;
485         while (pg) {
486                 unsigned long tmp = (unsigned long)pg;
487
488                 pg = pg->next;
489                 free_page(tmp);
490         }
491
492         free_page((unsigned long)stat->pages);
493         stat->pages = NULL;
494         stat->start = NULL;
495
496         return -ENOMEM;
497 }
498
499 static int ftrace_profile_init_cpu(int cpu)
500 {
501         struct ftrace_profile_stat *stat;
502         int size;
503
504         stat = &per_cpu(ftrace_profile_stats, cpu);
505
506         if (stat->hash) {
507                 /* If the profile is already created, simply reset it */
508                 ftrace_profile_reset(stat);
509                 return 0;
510         }
511
512         /*
513          * We are profiling all functions, but usually only a few thousand
514          * functions are hit. We'll make a hash of 1024 items.
515          */
516         size = FTRACE_PROFILE_HASH_SIZE;
517
518         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
519
520         if (!stat->hash)
521                 return -ENOMEM;
522
523         if (!ftrace_profile_bits) {
524                 size--;
525
526                 for (; size; size >>= 1)
527                         ftrace_profile_bits++;
528         }
529
530         /* Preallocate the function profiling pages */
531         if (ftrace_profile_pages_init(stat) < 0) {
532                 kfree(stat->hash);
533                 stat->hash = NULL;
534                 return -ENOMEM;
535         }
536
537         return 0;
538 }
539
540 static int ftrace_profile_init(void)
541 {
542         int cpu;
543         int ret = 0;
544
545         for_each_online_cpu(cpu) {
546                 ret = ftrace_profile_init_cpu(cpu);
547                 if (ret)
548                         break;
549         }
550
551         return ret;
552 }
553
554 /* interrupts must be disabled */
555 static struct ftrace_profile *
556 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
557 {
558         struct ftrace_profile *rec;
559         struct hlist_head *hhd;
560         struct hlist_node *n;
561         unsigned long key;
562
563         key = hash_long(ip, ftrace_profile_bits);
564         hhd = &stat->hash[key];
565
566         if (hlist_empty(hhd))
567                 return NULL;
568
569         hlist_for_each_entry_rcu(rec, n, hhd, node) {
570                 if (rec->ip == ip)
571                         return rec;
572         }
573
574         return NULL;
575 }
576
577 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
578                                struct ftrace_profile *rec)
579 {
580         unsigned long key;
581
582         key = hash_long(rec->ip, ftrace_profile_bits);
583         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
584 }
585
586 /*
587  * The memory is already allocated, this simply finds a new record to use.
588  */
589 static struct ftrace_profile *
590 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
591 {
592         struct ftrace_profile *rec = NULL;
593
594         /* prevent recursion (from NMIs) */
595         if (atomic_inc_return(&stat->disabled) != 1)
596                 goto out;
597
598         /*
599          * Try to find the function again since an NMI
600          * could have added it
601          */
602         rec = ftrace_find_profiled_func(stat, ip);
603         if (rec)
604                 goto out;
605
606         if (stat->pages->index == PROFILES_PER_PAGE) {
607                 if (!stat->pages->next)
608                         goto out;
609                 stat->pages = stat->pages->next;
610         }
611
612         rec = &stat->pages->records[stat->pages->index++];
613         rec->ip = ip;
614         ftrace_add_profile(stat, rec);
615
616  out:
617         atomic_dec(&stat->disabled);
618
619         return rec;
620 }
621
622 static void
623 function_profile_call(unsigned long ip, unsigned long parent_ip)
624 {
625         struct ftrace_profile_stat *stat;
626         struct ftrace_profile *rec;
627         unsigned long flags;
628
629         if (!ftrace_profile_enabled)
630                 return;
631
632         local_irq_save(flags);
633
634         stat = &__get_cpu_var(ftrace_profile_stats);
635         if (!stat->hash || !ftrace_profile_enabled)
636                 goto out;
637
638         rec = ftrace_find_profiled_func(stat, ip);
639         if (!rec) {
640                 rec = ftrace_profile_alloc(stat, ip);
641                 if (!rec)
642                         goto out;
643         }
644
645         rec->counter++;
646  out:
647         local_irq_restore(flags);
648 }
649
650 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
651 static int profile_graph_entry(struct ftrace_graph_ent *trace)
652 {
653         function_profile_call(trace->func, 0);
654         return 1;
655 }
656
657 static void profile_graph_return(struct ftrace_graph_ret *trace)
658 {
659         struct ftrace_profile_stat *stat;
660         unsigned long long calltime;
661         struct ftrace_profile *rec;
662         unsigned long flags;
663
664         local_irq_save(flags);
665         stat = &__get_cpu_var(ftrace_profile_stats);
666         if (!stat->hash || !ftrace_profile_enabled)
667                 goto out;
668
669         /* If the calltime was zero'd ignore it */
670         if (!trace->calltime)
671                 goto out;
672
673         calltime = trace->rettime - trace->calltime;
674
675         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
676                 int index;
677
678                 index = trace->depth;
679
680                 /* Append this call time to the parent time to subtract */
681                 if (index)
682                         current->ret_stack[index - 1].subtime += calltime;
683
684                 if (current->ret_stack[index].subtime < calltime)
685                         calltime -= current->ret_stack[index].subtime;
686                 else
687                         calltime = 0;
688         }
689
690         rec = ftrace_find_profiled_func(stat, trace->func);
691         if (rec) {
692                 rec->time += calltime;
693                 rec->time_squared += calltime * calltime;
694         }
695
696  out:
697         local_irq_restore(flags);
698 }
699
700 static int register_ftrace_profiler(void)
701 {
702         return register_ftrace_graph(&profile_graph_return,
703                                      &profile_graph_entry);
704 }
705
706 static void unregister_ftrace_profiler(void)
707 {
708         unregister_ftrace_graph();
709 }
710 #else
711 static struct ftrace_ops ftrace_profile_ops __read_mostly =
712 {
713         .func           = function_profile_call,
714 };
715
716 static int register_ftrace_profiler(void)
717 {
718         return register_ftrace_function(&ftrace_profile_ops);
719 }
720
721 static void unregister_ftrace_profiler(void)
722 {
723         unregister_ftrace_function(&ftrace_profile_ops);
724 }
725 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
726
727 static ssize_t
728 ftrace_profile_write(struct file *filp, const char __user *ubuf,
729                      size_t cnt, loff_t *ppos)
730 {
731         unsigned long val;
732         char buf[64];           /* big enough to hold a number */
733         int ret;
734
735         if (cnt >= sizeof(buf))
736                 return -EINVAL;
737
738         if (copy_from_user(&buf, ubuf, cnt))
739                 return -EFAULT;
740
741         buf[cnt] = 0;
742
743         ret = strict_strtoul(buf, 10, &val);
744         if (ret < 0)
745                 return ret;
746
747         val = !!val;
748
749         mutex_lock(&ftrace_profile_lock);
750         if (ftrace_profile_enabled ^ val) {
751                 if (val) {
752                         ret = ftrace_profile_init();
753                         if (ret < 0) {
754                                 cnt = ret;
755                                 goto out;
756                         }
757
758                         ret = register_ftrace_profiler();
759                         if (ret < 0) {
760                                 cnt = ret;
761                                 goto out;
762                         }
763                         ftrace_profile_enabled = 1;
764                 } else {
765                         ftrace_profile_enabled = 0;
766                         /*
767                          * unregister_ftrace_profiler calls stop_machine
768                          * so this acts like an synchronize_sched.
769                          */
770                         unregister_ftrace_profiler();
771                 }
772         }
773  out:
774         mutex_unlock(&ftrace_profile_lock);
775
776         *ppos += cnt;
777
778         return cnt;
779 }
780
781 static ssize_t
782 ftrace_profile_read(struct file *filp, char __user *ubuf,
783                      size_t cnt, loff_t *ppos)
784 {
785         char buf[64];           /* big enough to hold a number */
786         int r;
787
788         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
789         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
790 }
791
792 static const struct file_operations ftrace_profile_fops = {
793         .open           = tracing_open_generic,
794         .read           = ftrace_profile_read,
795         .write          = ftrace_profile_write,
796 };
797
798 /* used to initialize the real stat files */
799 static struct tracer_stat function_stats __initdata = {
800         .name           = "functions",
801         .stat_start     = function_stat_start,
802         .stat_next      = function_stat_next,
803         .stat_cmp       = function_stat_cmp,
804         .stat_headers   = function_stat_headers,
805         .stat_show      = function_stat_show
806 };
807
808 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
809 {
810         struct ftrace_profile_stat *stat;
811         struct dentry *entry;
812         char *name;
813         int ret;
814         int cpu;
815
816         for_each_possible_cpu(cpu) {
817                 stat = &per_cpu(ftrace_profile_stats, cpu);
818
819                 /* allocate enough for function name + cpu number */
820                 name = kmalloc(32, GFP_KERNEL);
821                 if (!name) {
822                         /*
823                          * The files created are permanent, if something happens
824                          * we still do not free memory.
825                          */
826                         WARN(1,
827                              "Could not allocate stat file for cpu %d\n",
828                              cpu);
829                         return;
830                 }
831                 stat->stat = function_stats;
832                 snprintf(name, 32, "function%d", cpu);
833                 stat->stat.name = name;
834                 ret = register_stat_tracer(&stat->stat);
835                 if (ret) {
836                         WARN(1,
837                              "Could not register function stat for cpu %d\n",
838                              cpu);
839                         kfree(name);
840                         return;
841                 }
842         }
843
844         entry = debugfs_create_file("function_profile_enabled", 0644,
845                                     d_tracer, NULL, &ftrace_profile_fops);
846         if (!entry)
847                 pr_warning("Could not create debugfs "
848                            "'function_profile_enabled' entry\n");
849 }
850
851 #else /* CONFIG_FUNCTION_PROFILER */
852 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
853 {
854 }
855 #endif /* CONFIG_FUNCTION_PROFILER */
856
857 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
858
859 #ifdef CONFIG_DYNAMIC_FTRACE
860
861 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
862 # error Dynamic ftrace depends on MCOUNT_RECORD
863 #endif
864
865 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
866
867 struct ftrace_func_probe {
868         struct hlist_node       node;
869         struct ftrace_probe_ops *ops;
870         unsigned long           flags;
871         unsigned long           ip;
872         void                    *data;
873         struct rcu_head         rcu;
874 };
875
876 enum {
877         FTRACE_ENABLE_CALLS             = (1 << 0),
878         FTRACE_DISABLE_CALLS            = (1 << 1),
879         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
880         FTRACE_ENABLE_MCOUNT            = (1 << 3),
881         FTRACE_DISABLE_MCOUNT           = (1 << 4),
882         FTRACE_START_FUNC_RET           = (1 << 5),
883         FTRACE_STOP_FUNC_RET            = (1 << 6),
884 };
885
886 static int ftrace_filtered;
887
888 static struct dyn_ftrace *ftrace_new_addrs;
889
890 static DEFINE_MUTEX(ftrace_regex_lock);
891
892 struct ftrace_page {
893         struct ftrace_page      *next;
894         int                     index;
895         struct dyn_ftrace       records[];
896 };
897
898 #define ENTRIES_PER_PAGE \
899   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
900
901 /* estimate from running different kernels */
902 #define NR_TO_INIT              10000
903
904 static struct ftrace_page       *ftrace_pages_start;
905 static struct ftrace_page       *ftrace_pages;
906
907 static struct dyn_ftrace *ftrace_free_records;
908
909 /*
910  * This is a double for. Do not use 'break' to break out of the loop,
911  * you must use a goto.
912  */
913 #define do_for_each_ftrace_rec(pg, rec)                                 \
914         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
915                 int _____i;                                             \
916                 for (_____i = 0; _____i < pg->index; _____i++) {        \
917                         rec = &pg->records[_____i];
918
919 #define while_for_each_ftrace_rec()             \
920                 }                               \
921         }
922
923 static void ftrace_free_rec(struct dyn_ftrace *rec)
924 {
925         rec->freelist = ftrace_free_records;
926         ftrace_free_records = rec;
927         rec->flags |= FTRACE_FL_FREE;
928 }
929
930 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
931 {
932         struct dyn_ftrace *rec;
933
934         /* First check for freed records */
935         if (ftrace_free_records) {
936                 rec = ftrace_free_records;
937
938                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
939                         FTRACE_WARN_ON_ONCE(1);
940                         ftrace_free_records = NULL;
941                         return NULL;
942                 }
943
944                 ftrace_free_records = rec->freelist;
945                 memset(rec, 0, sizeof(*rec));
946                 return rec;
947         }
948
949         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
950                 if (!ftrace_pages->next) {
951                         /* allocate another page */
952                         ftrace_pages->next =
953                                 (void *)get_zeroed_page(GFP_KERNEL);
954                         if (!ftrace_pages->next)
955                                 return NULL;
956                 }
957                 ftrace_pages = ftrace_pages->next;
958         }
959
960         return &ftrace_pages->records[ftrace_pages->index++];
961 }
962
963 static struct dyn_ftrace *
964 ftrace_record_ip(unsigned long ip)
965 {
966         struct dyn_ftrace *rec;
967
968         if (ftrace_disabled)
969                 return NULL;
970
971         rec = ftrace_alloc_dyn_node(ip);
972         if (!rec)
973                 return NULL;
974
975         rec->ip = ip;
976         rec->newlist = ftrace_new_addrs;
977         ftrace_new_addrs = rec;
978
979         return rec;
980 }
981
982 static void print_ip_ins(const char *fmt, unsigned char *p)
983 {
984         int i;
985
986         printk(KERN_CONT "%s", fmt);
987
988         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
989                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
990 }
991
992 static void ftrace_bug(int failed, unsigned long ip)
993 {
994         switch (failed) {
995         case -EFAULT:
996                 FTRACE_WARN_ON_ONCE(1);
997                 pr_info("ftrace faulted on modifying ");
998                 print_ip_sym(ip);
999                 break;
1000         case -EINVAL:
1001                 FTRACE_WARN_ON_ONCE(1);
1002                 pr_info("ftrace failed to modify ");
1003                 print_ip_sym(ip);
1004                 print_ip_ins(" actual: ", (unsigned char *)ip);
1005                 printk(KERN_CONT "\n");
1006                 break;
1007         case -EPERM:
1008                 FTRACE_WARN_ON_ONCE(1);
1009                 pr_info("ftrace faulted on writing ");
1010                 print_ip_sym(ip);
1011                 break;
1012         default:
1013                 FTRACE_WARN_ON_ONCE(1);
1014                 pr_info("ftrace faulted on unknown error ");
1015                 print_ip_sym(ip);
1016         }
1017 }
1018
1019
1020 /* Return 1 if the address range is reserved for ftrace */
1021 int ftrace_text_reserved(void *start, void *end)
1022 {
1023         struct dyn_ftrace *rec;
1024         struct ftrace_page *pg;
1025
1026         do_for_each_ftrace_rec(pg, rec) {
1027                 if (rec->ip <= (unsigned long)end &&
1028                     rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1029                         return 1;
1030         } while_for_each_ftrace_rec();
1031         return 0;
1032 }
1033
1034
1035 static int
1036 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1037 {
1038         unsigned long ftrace_addr;
1039         unsigned long flag = 0UL;
1040
1041         ftrace_addr = (unsigned long)FTRACE_ADDR;
1042
1043         /*
1044          * If this record is not to be traced or we want to disable it,
1045          * then disable it.
1046          *
1047          * If we want to enable it and filtering is off, then enable it.
1048          *
1049          * If we want to enable it and filtering is on, enable it only if
1050          * it's filtered
1051          */
1052         if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1053                 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1054                         flag = FTRACE_FL_ENABLED;
1055         }
1056
1057         /* If the state of this record hasn't changed, then do nothing */
1058         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1059                 return 0;
1060
1061         if (flag) {
1062                 rec->flags |= FTRACE_FL_ENABLED;
1063                 return ftrace_make_call(rec, ftrace_addr);
1064         }
1065
1066         rec->flags &= ~FTRACE_FL_ENABLED;
1067         return ftrace_make_nop(NULL, rec, ftrace_addr);
1068 }
1069
1070 static void ftrace_replace_code(int enable)
1071 {
1072         struct dyn_ftrace *rec;
1073         struct ftrace_page *pg;
1074         int failed;
1075
1076         do_for_each_ftrace_rec(pg, rec) {
1077                 /*
1078                  * Skip over free records, records that have
1079                  * failed and not converted.
1080                  */
1081                 if (rec->flags & FTRACE_FL_FREE ||
1082                     rec->flags & FTRACE_FL_FAILED ||
1083                     !(rec->flags & FTRACE_FL_CONVERTED))
1084                         continue;
1085
1086                 failed = __ftrace_replace_code(rec, enable);
1087                 if (failed) {
1088                         rec->flags |= FTRACE_FL_FAILED;
1089                         ftrace_bug(failed, rec->ip);
1090                         /* Stop processing */
1091                         return;
1092                 }
1093         } while_for_each_ftrace_rec();
1094 }
1095
1096 static int
1097 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1098 {
1099         unsigned long ip;
1100         int ret;
1101
1102         ip = rec->ip;
1103
1104         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1105         if (ret) {
1106                 ftrace_bug(ret, ip);
1107                 rec->flags |= FTRACE_FL_FAILED;
1108                 return 0;
1109         }
1110         return 1;
1111 }
1112
1113 /*
1114  * archs can override this function if they must do something
1115  * before the modifying code is performed.
1116  */
1117 int __weak ftrace_arch_code_modify_prepare(void)
1118 {
1119         return 0;
1120 }
1121
1122 /*
1123  * archs can override this function if they must do something
1124  * after the modifying code is performed.
1125  */
1126 int __weak ftrace_arch_code_modify_post_process(void)
1127 {
1128         return 0;
1129 }
1130
1131 static int __ftrace_modify_code(void *data)
1132 {
1133         int *command = data;
1134
1135         if (*command & FTRACE_ENABLE_CALLS)
1136                 ftrace_replace_code(1);
1137         else if (*command & FTRACE_DISABLE_CALLS)
1138                 ftrace_replace_code(0);
1139
1140         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1141                 ftrace_update_ftrace_func(ftrace_trace_function);
1142
1143         if (*command & FTRACE_START_FUNC_RET)
1144                 ftrace_enable_ftrace_graph_caller();
1145         else if (*command & FTRACE_STOP_FUNC_RET)
1146                 ftrace_disable_ftrace_graph_caller();
1147
1148         return 0;
1149 }
1150
1151 static void ftrace_run_update_code(int command)
1152 {
1153         int ret;
1154
1155         ret = ftrace_arch_code_modify_prepare();
1156         FTRACE_WARN_ON(ret);
1157         if (ret)
1158                 return;
1159
1160         stop_machine(__ftrace_modify_code, &command, NULL);
1161
1162         ret = ftrace_arch_code_modify_post_process();
1163         FTRACE_WARN_ON(ret);
1164 }
1165
1166 static ftrace_func_t saved_ftrace_func;
1167 static int ftrace_start_up;
1168
1169 static void ftrace_startup_enable(int command)
1170 {
1171         if (saved_ftrace_func != ftrace_trace_function) {
1172                 saved_ftrace_func = ftrace_trace_function;
1173                 command |= FTRACE_UPDATE_TRACE_FUNC;
1174         }
1175
1176         if (!command || !ftrace_enabled)
1177                 return;
1178
1179         ftrace_run_update_code(command);
1180 }
1181
1182 static void ftrace_startup(int command)
1183 {
1184         if (unlikely(ftrace_disabled))
1185                 return;
1186
1187         ftrace_start_up++;
1188         command |= FTRACE_ENABLE_CALLS;
1189
1190         ftrace_startup_enable(command);
1191 }
1192
1193 static void ftrace_shutdown(int command)
1194 {
1195         if (unlikely(ftrace_disabled))
1196                 return;
1197
1198         ftrace_start_up--;
1199         /*
1200          * Just warn in case of unbalance, no need to kill ftrace, it's not
1201          * critical but the ftrace_call callers may be never nopped again after
1202          * further ftrace uses.
1203          */
1204         WARN_ON_ONCE(ftrace_start_up < 0);
1205
1206         if (!ftrace_start_up)
1207                 command |= FTRACE_DISABLE_CALLS;
1208
1209         if (saved_ftrace_func != ftrace_trace_function) {
1210                 saved_ftrace_func = ftrace_trace_function;
1211                 command |= FTRACE_UPDATE_TRACE_FUNC;
1212         }
1213
1214         if (!command || !ftrace_enabled)
1215                 return;
1216
1217         ftrace_run_update_code(command);
1218 }
1219
1220 static void ftrace_startup_sysctl(void)
1221 {
1222         int command = FTRACE_ENABLE_MCOUNT;
1223
1224         if (unlikely(ftrace_disabled))
1225                 return;
1226
1227         /* Force update next time */
1228         saved_ftrace_func = NULL;
1229         /* ftrace_start_up is true if we want ftrace running */
1230         if (ftrace_start_up)
1231                 command |= FTRACE_ENABLE_CALLS;
1232
1233         ftrace_run_update_code(command);
1234 }
1235
1236 static void ftrace_shutdown_sysctl(void)
1237 {
1238         int command = FTRACE_DISABLE_MCOUNT;
1239
1240         if (unlikely(ftrace_disabled))
1241                 return;
1242
1243         /* ftrace_start_up is true if ftrace is running */
1244         if (ftrace_start_up)
1245                 command |= FTRACE_DISABLE_CALLS;
1246
1247         ftrace_run_update_code(command);
1248 }
1249
1250 static cycle_t          ftrace_update_time;
1251 static unsigned long    ftrace_update_cnt;
1252 unsigned long           ftrace_update_tot_cnt;
1253
1254 static int ftrace_update_code(struct module *mod)
1255 {
1256         struct dyn_ftrace *p;
1257         cycle_t start, stop;
1258
1259         start = ftrace_now(raw_smp_processor_id());
1260         ftrace_update_cnt = 0;
1261
1262         while (ftrace_new_addrs) {
1263
1264                 /* If something went wrong, bail without enabling anything */
1265                 if (unlikely(ftrace_disabled))
1266                         return -1;
1267
1268                 p = ftrace_new_addrs;
1269                 ftrace_new_addrs = p->newlist;
1270                 p->flags = 0L;
1271
1272                 /*
1273                  * Do the initial record convertion from mcount jump
1274                  * to the NOP instructions.
1275                  */
1276                 if (!ftrace_code_disable(mod, p)) {
1277                         ftrace_free_rec(p);
1278                         continue;
1279                 }
1280
1281                 p->flags |= FTRACE_FL_CONVERTED;
1282                 ftrace_update_cnt++;
1283
1284                 /*
1285                  * If the tracing is enabled, go ahead and enable the record.
1286                  *
1287                  * The reason not to enable the record immediatelly is the
1288                  * inherent check of ftrace_make_nop/ftrace_make_call for
1289                  * correct previous instructions.  Making first the NOP
1290                  * conversion puts the module to the correct state, thus
1291                  * passing the ftrace_make_call check.
1292                  */
1293                 if (ftrace_start_up) {
1294                         int failed = __ftrace_replace_code(p, 1);
1295                         if (failed) {
1296                                 ftrace_bug(failed, p->ip);
1297                                 ftrace_free_rec(p);
1298                         }
1299                 }
1300         }
1301
1302         stop = ftrace_now(raw_smp_processor_id());
1303         ftrace_update_time = stop - start;
1304         ftrace_update_tot_cnt += ftrace_update_cnt;
1305
1306         return 0;
1307 }
1308
1309 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1310 {
1311         struct ftrace_page *pg;
1312         int cnt;
1313         int i;
1314
1315         /* allocate a few pages */
1316         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1317         if (!ftrace_pages_start)
1318                 return -1;
1319
1320         /*
1321          * Allocate a few more pages.
1322          *
1323          * TODO: have some parser search vmlinux before
1324          *   final linking to find all calls to ftrace.
1325          *   Then we can:
1326          *    a) know how many pages to allocate.
1327          *     and/or
1328          *    b) set up the table then.
1329          *
1330          *  The dynamic code is still necessary for
1331          *  modules.
1332          */
1333
1334         pg = ftrace_pages = ftrace_pages_start;
1335
1336         cnt = num_to_init / ENTRIES_PER_PAGE;
1337         pr_info("ftrace: allocating %ld entries in %d pages\n",
1338                 num_to_init, cnt + 1);
1339
1340         for (i = 0; i < cnt; i++) {
1341                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1342
1343                 /* If we fail, we'll try later anyway */
1344                 if (!pg->next)
1345                         break;
1346
1347                 pg = pg->next;
1348         }
1349
1350         return 0;
1351 }
1352
1353 enum {
1354         FTRACE_ITER_FILTER      = (1 << 0),
1355         FTRACE_ITER_NOTRACE     = (1 << 1),
1356         FTRACE_ITER_FAILURES    = (1 << 2),
1357         FTRACE_ITER_PRINTALL    = (1 << 3),
1358         FTRACE_ITER_HASH        = (1 << 4),
1359 };
1360
1361 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1362
1363 struct ftrace_iterator {
1364         struct ftrace_page      *pg;
1365         int                     hidx;
1366         int                     idx;
1367         unsigned                flags;
1368         struct trace_parser     parser;
1369 };
1370
1371 static void *
1372 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1373 {
1374         struct ftrace_iterator *iter = m->private;
1375         struct hlist_node *hnd = v;
1376         struct hlist_head *hhd;
1377
1378         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1379
1380         (*pos)++;
1381
1382  retry:
1383         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1384                 return NULL;
1385
1386         hhd = &ftrace_func_hash[iter->hidx];
1387
1388         if (hlist_empty(hhd)) {
1389                 iter->hidx++;
1390                 hnd = NULL;
1391                 goto retry;
1392         }
1393
1394         if (!hnd)
1395                 hnd = hhd->first;
1396         else {
1397                 hnd = hnd->next;
1398                 if (!hnd) {
1399                         iter->hidx++;
1400                         goto retry;
1401                 }
1402         }
1403
1404         return hnd;
1405 }
1406
1407 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1408 {
1409         struct ftrace_iterator *iter = m->private;
1410         void *p = NULL;
1411         loff_t l;
1412
1413         if (!(iter->flags & FTRACE_ITER_HASH))
1414                 *pos = 0;
1415
1416         iter->flags |= FTRACE_ITER_HASH;
1417
1418         iter->hidx = 0;
1419         for (l = 0; l <= *pos; ) {
1420                 p = t_hash_next(m, p, &l);
1421                 if (!p)
1422                         break;
1423         }
1424         return p;
1425 }
1426
1427 static int t_hash_show(struct seq_file *m, void *v)
1428 {
1429         struct ftrace_func_probe *rec;
1430         struct hlist_node *hnd = v;
1431
1432         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1433
1434         if (rec->ops->print)
1435                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1436
1437         seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1438
1439         if (rec->data)
1440                 seq_printf(m, ":%p", rec->data);
1441         seq_putc(m, '\n');
1442
1443         return 0;
1444 }
1445
1446 static void *
1447 t_next(struct seq_file *m, void *v, loff_t *pos)
1448 {
1449         struct ftrace_iterator *iter = m->private;
1450         struct dyn_ftrace *rec = NULL;
1451
1452         if (iter->flags & FTRACE_ITER_HASH)
1453                 return t_hash_next(m, v, pos);
1454
1455         (*pos)++;
1456
1457         if (iter->flags & FTRACE_ITER_PRINTALL)
1458                 return NULL;
1459
1460  retry:
1461         if (iter->idx >= iter->pg->index) {
1462                 if (iter->pg->next) {
1463                         iter->pg = iter->pg->next;
1464                         iter->idx = 0;
1465                         goto retry;
1466                 }
1467         } else {
1468                 rec = &iter->pg->records[iter->idx++];
1469                 if ((rec->flags & FTRACE_FL_FREE) ||
1470
1471                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
1472                      (rec->flags & FTRACE_FL_FAILED)) ||
1473
1474                     ((iter->flags & FTRACE_ITER_FAILURES) &&
1475                      !(rec->flags & FTRACE_FL_FAILED)) ||
1476
1477                     ((iter->flags & FTRACE_ITER_FILTER) &&
1478                      !(rec->flags & FTRACE_FL_FILTER)) ||
1479
1480                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
1481                      !(rec->flags & FTRACE_FL_NOTRACE))) {
1482                         rec = NULL;
1483                         goto retry;
1484                 }
1485         }
1486
1487         return rec;
1488 }
1489
1490 static void *t_start(struct seq_file *m, loff_t *pos)
1491 {
1492         struct ftrace_iterator *iter = m->private;
1493         void *p = NULL;
1494         loff_t l;
1495
1496         mutex_lock(&ftrace_lock);
1497         /*
1498          * For set_ftrace_filter reading, if we have the filter
1499          * off, we can short cut and just print out that all
1500          * functions are enabled.
1501          */
1502         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1503                 if (*pos > 0)
1504                         return t_hash_start(m, pos);
1505                 iter->flags |= FTRACE_ITER_PRINTALL;
1506                 return iter;
1507         }
1508
1509         if (iter->flags & FTRACE_ITER_HASH)
1510                 return t_hash_start(m, pos);
1511
1512         iter->pg = ftrace_pages_start;
1513         iter->idx = 0;
1514         for (l = 0; l <= *pos; ) {
1515                 p = t_next(m, p, &l);
1516                 if (!p)
1517                         break;
1518         }
1519
1520         if (!p && iter->flags & FTRACE_ITER_FILTER)
1521                 return t_hash_start(m, pos);
1522
1523         return p;
1524 }
1525
1526 static void t_stop(struct seq_file *m, void *p)
1527 {
1528         mutex_unlock(&ftrace_lock);
1529 }
1530
1531 static int t_show(struct seq_file *m, void *v)
1532 {
1533         struct ftrace_iterator *iter = m->private;
1534         struct dyn_ftrace *rec = v;
1535
1536         if (iter->flags & FTRACE_ITER_HASH)
1537                 return t_hash_show(m, v);
1538
1539         if (iter->flags & FTRACE_ITER_PRINTALL) {
1540                 seq_printf(m, "#### all functions enabled ####\n");
1541                 return 0;
1542         }
1543
1544         if (!rec)
1545                 return 0;
1546
1547         seq_printf(m, "%ps\n", (void *)rec->ip);
1548
1549         return 0;
1550 }
1551
1552 static const struct seq_operations show_ftrace_seq_ops = {
1553         .start = t_start,
1554         .next = t_next,
1555         .stop = t_stop,
1556         .show = t_show,
1557 };
1558
1559 static int
1560 ftrace_avail_open(struct inode *inode, struct file *file)
1561 {
1562         struct ftrace_iterator *iter;
1563         int ret;
1564
1565         if (unlikely(ftrace_disabled))
1566                 return -ENODEV;
1567
1568         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1569         if (!iter)
1570                 return -ENOMEM;
1571
1572         iter->pg = ftrace_pages_start;
1573
1574         ret = seq_open(file, &show_ftrace_seq_ops);
1575         if (!ret) {
1576                 struct seq_file *m = file->private_data;
1577
1578                 m->private = iter;
1579         } else {
1580                 kfree(iter);
1581         }
1582
1583         return ret;
1584 }
1585
1586 static int
1587 ftrace_failures_open(struct inode *inode, struct file *file)
1588 {
1589         int ret;
1590         struct seq_file *m;
1591         struct ftrace_iterator *iter;
1592
1593         ret = ftrace_avail_open(inode, file);
1594         if (!ret) {
1595                 m = (struct seq_file *)file->private_data;
1596                 iter = (struct ftrace_iterator *)m->private;
1597                 iter->flags = FTRACE_ITER_FAILURES;
1598         }
1599
1600         return ret;
1601 }
1602
1603
1604 static void ftrace_filter_reset(int enable)
1605 {
1606         struct ftrace_page *pg;
1607         struct dyn_ftrace *rec;
1608         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1609
1610         mutex_lock(&ftrace_lock);
1611         if (enable)
1612                 ftrace_filtered = 0;
1613         do_for_each_ftrace_rec(pg, rec) {
1614                 if (rec->flags & FTRACE_FL_FAILED)
1615                         continue;
1616                 rec->flags &= ~type;
1617         } while_for_each_ftrace_rec();
1618         mutex_unlock(&ftrace_lock);
1619 }
1620
1621 static int
1622 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1623 {
1624         struct ftrace_iterator *iter;
1625         int ret = 0;
1626
1627         if (unlikely(ftrace_disabled))
1628                 return -ENODEV;
1629
1630         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1631         if (!iter)
1632                 return -ENOMEM;
1633
1634         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1635                 kfree(iter);
1636                 return -ENOMEM;
1637         }
1638
1639         mutex_lock(&ftrace_regex_lock);
1640         if ((file->f_mode & FMODE_WRITE) &&
1641             (file->f_flags & O_TRUNC))
1642                 ftrace_filter_reset(enable);
1643
1644         if (file->f_mode & FMODE_READ) {
1645                 iter->pg = ftrace_pages_start;
1646                 iter->flags = enable ? FTRACE_ITER_FILTER :
1647                         FTRACE_ITER_NOTRACE;
1648
1649                 ret = seq_open(file, &show_ftrace_seq_ops);
1650                 if (!ret) {
1651                         struct seq_file *m = file->private_data;
1652                         m->private = iter;
1653                 } else {
1654                         trace_parser_put(&iter->parser);
1655                         kfree(iter);
1656                 }
1657         } else
1658                 file->private_data = iter;
1659         mutex_unlock(&ftrace_regex_lock);
1660
1661         return ret;
1662 }
1663
1664 static int
1665 ftrace_filter_open(struct inode *inode, struct file *file)
1666 {
1667         return ftrace_regex_open(inode, file, 1);
1668 }
1669
1670 static int
1671 ftrace_notrace_open(struct inode *inode, struct file *file)
1672 {
1673         return ftrace_regex_open(inode, file, 0);
1674 }
1675
1676 static loff_t
1677 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1678 {
1679         loff_t ret;
1680
1681         if (file->f_mode & FMODE_READ)
1682                 ret = seq_lseek(file, offset, origin);
1683         else
1684                 file->f_pos = ret = 1;
1685
1686         return ret;
1687 }
1688
1689 static int ftrace_match(char *str, char *regex, int len, int type)
1690 {
1691         int matched = 0;
1692         int slen;
1693
1694         switch (type) {
1695         case MATCH_FULL:
1696                 if (strcmp(str, regex) == 0)
1697                         matched = 1;
1698                 break;
1699         case MATCH_FRONT_ONLY:
1700                 if (strncmp(str, regex, len) == 0)
1701                         matched = 1;
1702                 break;
1703         case MATCH_MIDDLE_ONLY:
1704                 if (strstr(str, regex))
1705                         matched = 1;
1706                 break;
1707         case MATCH_END_ONLY:
1708                 slen = strlen(str);
1709                 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1710                         matched = 1;
1711                 break;
1712         }
1713
1714         return matched;
1715 }
1716
1717 static int
1718 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1719 {
1720         char str[KSYM_SYMBOL_LEN];
1721
1722         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1723         return ftrace_match(str, regex, len, type);
1724 }
1725
1726 static int ftrace_match_records(char *buff, int len, int enable)
1727 {
1728         unsigned int search_len;
1729         struct ftrace_page *pg;
1730         struct dyn_ftrace *rec;
1731         unsigned long flag;
1732         char *search;
1733         int type;
1734         int not;
1735         int found = 0;
1736
1737         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1738         type = filter_parse_regex(buff, len, &search, &not);
1739
1740         search_len = strlen(search);
1741
1742         mutex_lock(&ftrace_lock);
1743         do_for_each_ftrace_rec(pg, rec) {
1744
1745                 if (rec->flags & FTRACE_FL_FAILED)
1746                         continue;
1747
1748                 if (ftrace_match_record(rec, search, search_len, type)) {
1749                         if (not)
1750                                 rec->flags &= ~flag;
1751                         else
1752                                 rec->flags |= flag;
1753                         found = 1;
1754                 }
1755                 /*
1756                  * Only enable filtering if we have a function that
1757                  * is filtered on.
1758                  */
1759                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1760                         ftrace_filtered = 1;
1761         } while_for_each_ftrace_rec();
1762         mutex_unlock(&ftrace_lock);
1763
1764         return found;
1765 }
1766
1767 static int
1768 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1769                            char *regex, int len, int type)
1770 {
1771         char str[KSYM_SYMBOL_LEN];
1772         char *modname;
1773
1774         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1775
1776         if (!modname || strcmp(modname, mod))
1777                 return 0;
1778
1779         /* blank search means to match all funcs in the mod */
1780         if (len)
1781                 return ftrace_match(str, regex, len, type);
1782         else
1783                 return 1;
1784 }
1785
1786 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1787 {
1788         unsigned search_len = 0;
1789         struct ftrace_page *pg;
1790         struct dyn_ftrace *rec;
1791         int type = MATCH_FULL;
1792         char *search = buff;
1793         unsigned long flag;
1794         int not = 0;
1795         int found = 0;
1796
1797         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1798
1799         /* blank or '*' mean the same */
1800         if (strcmp(buff, "*") == 0)
1801                 buff[0] = 0;
1802
1803         /* handle the case of 'dont filter this module' */
1804         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1805                 buff[0] = 0;
1806                 not = 1;
1807         }
1808
1809         if (strlen(buff)) {
1810                 type = filter_parse_regex(buff, strlen(buff), &search, &not);
1811                 search_len = strlen(search);
1812         }
1813
1814         mutex_lock(&ftrace_lock);
1815         do_for_each_ftrace_rec(pg, rec) {
1816
1817                 if (rec->flags & FTRACE_FL_FAILED)
1818                         continue;
1819
1820                 if (ftrace_match_module_record(rec, mod,
1821                                                search, search_len, type)) {
1822                         if (not)
1823                                 rec->flags &= ~flag;
1824                         else
1825                                 rec->flags |= flag;
1826                         found = 1;
1827                 }
1828                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1829                         ftrace_filtered = 1;
1830
1831         } while_for_each_ftrace_rec();
1832         mutex_unlock(&ftrace_lock);
1833
1834         return found;
1835 }
1836
1837 /*
1838  * We register the module command as a template to show others how
1839  * to register the a command as well.
1840  */
1841
1842 static int
1843 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1844 {
1845         char *mod;
1846
1847         /*
1848          * cmd == 'mod' because we only registered this func
1849          * for the 'mod' ftrace_func_command.
1850          * But if you register one func with multiple commands,
1851          * you can tell which command was used by the cmd
1852          * parameter.
1853          */
1854
1855         /* we must have a module name */
1856         if (!param)
1857                 return -EINVAL;
1858
1859         mod = strsep(&param, ":");
1860         if (!strlen(mod))
1861                 return -EINVAL;
1862
1863         if (ftrace_match_module_records(func, mod, enable))
1864                 return 0;
1865         return -EINVAL;
1866 }
1867
1868 static struct ftrace_func_command ftrace_mod_cmd = {
1869         .name                   = "mod",
1870         .func                   = ftrace_mod_callback,
1871 };
1872
1873 static int __init ftrace_mod_cmd_init(void)
1874 {
1875         return register_ftrace_command(&ftrace_mod_cmd);
1876 }
1877 device_initcall(ftrace_mod_cmd_init);
1878
1879 static void
1880 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1881 {
1882         struct ftrace_func_probe *entry;
1883         struct hlist_head *hhd;
1884         struct hlist_node *n;
1885         unsigned long key;
1886         int resched;
1887
1888         key = hash_long(ip, FTRACE_HASH_BITS);
1889
1890         hhd = &ftrace_func_hash[key];
1891
1892         if (hlist_empty(hhd))
1893                 return;
1894
1895         /*
1896          * Disable preemption for these calls to prevent a RCU grace
1897          * period. This syncs the hash iteration and freeing of items
1898          * on the hash. rcu_read_lock is too dangerous here.
1899          */
1900         resched = ftrace_preempt_disable();
1901         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1902                 if (entry->ip == ip)
1903                         entry->ops->func(ip, parent_ip, &entry->data);
1904         }
1905         ftrace_preempt_enable(resched);
1906 }
1907
1908 static struct ftrace_ops trace_probe_ops __read_mostly =
1909 {
1910         .func           = function_trace_probe_call,
1911 };
1912
1913 static int ftrace_probe_registered;
1914
1915 static void __enable_ftrace_function_probe(void)
1916 {
1917         int i;
1918
1919         if (ftrace_probe_registered)
1920                 return;
1921
1922         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1923                 struct hlist_head *hhd = &ftrace_func_hash[i];
1924                 if (hhd->first)
1925                         break;
1926         }
1927         /* Nothing registered? */
1928         if (i == FTRACE_FUNC_HASHSIZE)
1929                 return;
1930
1931         __register_ftrace_function(&trace_probe_ops);
1932         ftrace_startup(0);
1933         ftrace_probe_registered = 1;
1934 }
1935
1936 static void __disable_ftrace_function_probe(void)
1937 {
1938         int i;
1939
1940         if (!ftrace_probe_registered)
1941                 return;
1942
1943         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1944                 struct hlist_head *hhd = &ftrace_func_hash[i];
1945                 if (hhd->first)
1946                         return;
1947         }
1948
1949         /* no more funcs left */
1950         __unregister_ftrace_function(&trace_probe_ops);
1951         ftrace_shutdown(0);
1952         ftrace_probe_registered = 0;
1953 }
1954
1955
1956 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1957 {
1958         struct ftrace_func_probe *entry =
1959                 container_of(rhp, struct ftrace_func_probe, rcu);
1960
1961         if (entry->ops->free)
1962                 entry->ops->free(&entry->data);
1963         kfree(entry);
1964 }
1965
1966
1967 int
1968 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1969                               void *data)
1970 {
1971         struct ftrace_func_probe *entry;
1972         struct ftrace_page *pg;
1973         struct dyn_ftrace *rec;
1974         int type, len, not;
1975         unsigned long key;
1976         int count = 0;
1977         char *search;
1978
1979         type = filter_parse_regex(glob, strlen(glob), &search, &not);
1980         len = strlen(search);
1981
1982         /* we do not support '!' for function probes */
1983         if (WARN_ON(not))
1984                 return -EINVAL;
1985
1986         mutex_lock(&ftrace_lock);
1987         do_for_each_ftrace_rec(pg, rec) {
1988
1989                 if (rec->flags & FTRACE_FL_FAILED)
1990                         continue;
1991
1992                 if (!ftrace_match_record(rec, search, len, type))
1993                         continue;
1994
1995                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1996                 if (!entry) {
1997                         /* If we did not process any, then return error */
1998                         if (!count)
1999                                 count = -ENOMEM;
2000                         goto out_unlock;
2001                 }
2002
2003                 count++;
2004
2005                 entry->data = data;
2006
2007                 /*
2008                  * The caller might want to do something special
2009                  * for each function we find. We call the callback
2010                  * to give the caller an opportunity to do so.
2011                  */
2012                 if (ops->callback) {
2013                         if (ops->callback(rec->ip, &entry->data) < 0) {
2014                                 /* caller does not like this func */
2015                                 kfree(entry);
2016                                 continue;
2017                         }
2018                 }
2019
2020                 entry->ops = ops;
2021                 entry->ip = rec->ip;
2022
2023                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2024                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2025
2026         } while_for_each_ftrace_rec();
2027         __enable_ftrace_function_probe();
2028
2029  out_unlock:
2030         mutex_unlock(&ftrace_lock);
2031
2032         return count;
2033 }
2034
2035 enum {
2036         PROBE_TEST_FUNC         = 1,
2037         PROBE_TEST_DATA         = 2
2038 };
2039
2040 static void
2041 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2042                                   void *data, int flags)
2043 {
2044         struct ftrace_func_probe *entry;
2045         struct hlist_node *n, *tmp;
2046         char str[KSYM_SYMBOL_LEN];
2047         int type = MATCH_FULL;
2048         int i, len = 0;
2049         char *search;
2050
2051         if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2052                 glob = NULL;
2053         else if (glob) {
2054                 int not;
2055
2056                 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2057                 len = strlen(search);
2058
2059                 /* we do not support '!' for function probes */
2060                 if (WARN_ON(not))
2061                         return;
2062         }
2063
2064         mutex_lock(&ftrace_lock);
2065         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2066                 struct hlist_head *hhd = &ftrace_func_hash[i];
2067
2068                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2069
2070                         /* break up if statements for readability */
2071                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2072                                 continue;
2073
2074                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2075                                 continue;
2076
2077                         /* do this last, since it is the most expensive */
2078                         if (glob) {
2079                                 kallsyms_lookup(entry->ip, NULL, NULL,
2080                                                 NULL, str);
2081                                 if (!ftrace_match(str, glob, len, type))
2082                                         continue;
2083                         }
2084
2085                         hlist_del(&entry->node);
2086                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2087                 }
2088         }
2089         __disable_ftrace_function_probe();
2090         mutex_unlock(&ftrace_lock);
2091 }
2092
2093 void
2094 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2095                                 void *data)
2096 {
2097         __unregister_ftrace_function_probe(glob, ops, data,
2098                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2099 }
2100
2101 void
2102 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2103 {
2104         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2105 }
2106
2107 void unregister_ftrace_function_probe_all(char *glob)
2108 {
2109         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2110 }
2111
2112 static LIST_HEAD(ftrace_commands);
2113 static DEFINE_MUTEX(ftrace_cmd_mutex);
2114
2115 int register_ftrace_command(struct ftrace_func_command *cmd)
2116 {
2117         struct ftrace_func_command *p;
2118         int ret = 0;
2119
2120         mutex_lock(&ftrace_cmd_mutex);
2121         list_for_each_entry(p, &ftrace_commands, list) {
2122                 if (strcmp(cmd->name, p->name) == 0) {
2123                         ret = -EBUSY;
2124                         goto out_unlock;
2125                 }
2126         }
2127         list_add(&cmd->list, &ftrace_commands);
2128  out_unlock:
2129         mutex_unlock(&ftrace_cmd_mutex);
2130
2131         return ret;
2132 }
2133
2134 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2135 {
2136         struct ftrace_func_command *p, *n;
2137         int ret = -ENODEV;
2138
2139         mutex_lock(&ftrace_cmd_mutex);
2140         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2141                 if (strcmp(cmd->name, p->name) == 0) {
2142                         ret = 0;
2143                         list_del_init(&p->list);
2144                         goto out_unlock;
2145                 }
2146         }
2147  out_unlock:
2148         mutex_unlock(&ftrace_cmd_mutex);
2149
2150         return ret;
2151 }
2152
2153 static int ftrace_process_regex(char *buff, int len, int enable)
2154 {
2155         char *func, *command, *next = buff;
2156         struct ftrace_func_command *p;
2157         int ret = -EINVAL;
2158
2159         func = strsep(&next, ":");
2160
2161         if (!next) {
2162                 if (ftrace_match_records(func, len, enable))
2163                         return 0;
2164                 return ret;
2165         }
2166
2167         /* command found */
2168
2169         command = strsep(&next, ":");
2170
2171         mutex_lock(&ftrace_cmd_mutex);
2172         list_for_each_entry(p, &ftrace_commands, list) {
2173                 if (strcmp(p->name, command) == 0) {
2174                         ret = p->func(func, command, next, enable);
2175                         goto out_unlock;
2176                 }
2177         }
2178  out_unlock:
2179         mutex_unlock(&ftrace_cmd_mutex);
2180
2181         return ret;
2182 }
2183
2184 static ssize_t
2185 ftrace_regex_write(struct file *file, const char __user *ubuf,
2186                    size_t cnt, loff_t *ppos, int enable)
2187 {
2188         struct ftrace_iterator *iter;
2189         struct trace_parser *parser;
2190         ssize_t ret, read;
2191
2192         if (!cnt)
2193                 return 0;
2194
2195         mutex_lock(&ftrace_regex_lock);
2196
2197         if (file->f_mode & FMODE_READ) {
2198                 struct seq_file *m = file->private_data;
2199                 iter = m->private;
2200         } else
2201                 iter = file->private_data;
2202
2203         parser = &iter->parser;
2204         read = trace_get_user(parser, ubuf, cnt, ppos);
2205
2206         if (read >= 0 && trace_parser_loaded(parser) &&
2207             !trace_parser_cont(parser)) {
2208                 ret = ftrace_process_regex(parser->buffer,
2209                                            parser->idx, enable);
2210                 trace_parser_clear(parser);
2211                 if (ret)
2212                         goto out_unlock;
2213         }
2214
2215         ret = read;
2216 out_unlock:
2217         mutex_unlock(&ftrace_regex_lock);
2218
2219         return ret;
2220 }
2221
2222 static ssize_t
2223 ftrace_filter_write(struct file *file, const char __user *ubuf,
2224                     size_t cnt, loff_t *ppos)
2225 {
2226         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2227 }
2228
2229 static ssize_t
2230 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2231                      size_t cnt, loff_t *ppos)
2232 {
2233         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2234 }
2235
2236 static void
2237 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2238 {
2239         if (unlikely(ftrace_disabled))
2240                 return;
2241
2242         mutex_lock(&ftrace_regex_lock);
2243         if (reset)
2244                 ftrace_filter_reset(enable);
2245         if (buf)
2246                 ftrace_match_records(buf, len, enable);
2247         mutex_unlock(&ftrace_regex_lock);
2248 }
2249
2250 /**
2251  * ftrace_set_filter - set a function to filter on in ftrace
2252  * @buf - the string that holds the function filter text.
2253  * @len - the length of the string.
2254  * @reset - non zero to reset all filters before applying this filter.
2255  *
2256  * Filters denote which functions should be enabled when tracing is enabled.
2257  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2258  */
2259 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2260 {
2261         ftrace_set_regex(buf, len, reset, 1);
2262 }
2263
2264 /**
2265  * ftrace_set_notrace - set a function to not trace in ftrace
2266  * @buf - the string that holds the function notrace text.
2267  * @len - the length of the string.
2268  * @reset - non zero to reset all filters before applying this filter.
2269  *
2270  * Notrace Filters denote which functions should not be enabled when tracing
2271  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2272  * for tracing.
2273  */
2274 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2275 {
2276         ftrace_set_regex(buf, len, reset, 0);
2277 }
2278
2279 /*
2280  * command line interface to allow users to set filters on boot up.
2281  */
2282 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
2283 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2284 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2285
2286 static int __init set_ftrace_notrace(char *str)
2287 {
2288         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2289         return 1;
2290 }
2291 __setup("ftrace_notrace=", set_ftrace_notrace);
2292
2293 static int __init set_ftrace_filter(char *str)
2294 {
2295         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2296         return 1;
2297 }
2298 __setup("ftrace_filter=", set_ftrace_filter);
2299
2300 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2301 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2302 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
2303
2304 static int __init set_graph_function(char *str)
2305 {
2306         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2307         return 1;
2308 }
2309 __setup("ftrace_graph_filter=", set_graph_function);
2310
2311 static void __init set_ftrace_early_graph(char *buf)
2312 {
2313         int ret;
2314         char *func;
2315
2316         while (buf) {
2317                 func = strsep(&buf, ",");
2318                 /* we allow only one expression at a time */
2319                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2320                                       func);
2321                 if (ret)
2322                         printk(KERN_DEBUG "ftrace: function %s not "
2323                                           "traceable\n", func);
2324         }
2325 }
2326 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2327
2328 static void __init set_ftrace_early_filter(char *buf, int enable)
2329 {
2330         char *func;
2331
2332         while (buf) {
2333                 func = strsep(&buf, ",");
2334                 ftrace_set_regex(func, strlen(func), 0, enable);
2335         }
2336 }
2337
2338 static void __init set_ftrace_early_filters(void)
2339 {
2340         if (ftrace_filter_buf[0])
2341                 set_ftrace_early_filter(ftrace_filter_buf, 1);
2342         if (ftrace_notrace_buf[0])
2343                 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2344 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2345         if (ftrace_graph_buf[0])
2346                 set_ftrace_early_graph(ftrace_graph_buf);
2347 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2348 }
2349
2350 static int
2351 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2352 {
2353         struct seq_file *m = (struct seq_file *)file->private_data;
2354         struct ftrace_iterator *iter;
2355         struct trace_parser *parser;
2356
2357         mutex_lock(&ftrace_regex_lock);
2358         if (file->f_mode & FMODE_READ) {
2359                 iter = m->private;
2360
2361                 seq_release(inode, file);
2362         } else
2363                 iter = file->private_data;
2364
2365         parser = &iter->parser;
2366         if (trace_parser_loaded(parser)) {
2367                 parser->buffer[parser->idx] = 0;
2368                 ftrace_match_records(parser->buffer, parser->idx, enable);
2369         }
2370
2371         mutex_lock(&ftrace_lock);
2372         if (ftrace_start_up && ftrace_enabled)
2373                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2374         mutex_unlock(&ftrace_lock);
2375
2376         trace_parser_put(parser);
2377         kfree(iter);
2378
2379         mutex_unlock(&ftrace_regex_lock);
2380         return 0;
2381 }
2382
2383 static int
2384 ftrace_filter_release(struct inode *inode, struct file *file)
2385 {
2386         return ftrace_regex_release(inode, file, 1);
2387 }
2388
2389 static int
2390 ftrace_notrace_release(struct inode *inode, struct file *file)
2391 {
2392         return ftrace_regex_release(inode, file, 0);
2393 }
2394
2395 static const struct file_operations ftrace_avail_fops = {
2396         .open = ftrace_avail_open,
2397         .read = seq_read,
2398         .llseek = seq_lseek,
2399         .release = seq_release_private,
2400 };
2401
2402 static const struct file_operations ftrace_failures_fops = {
2403         .open = ftrace_failures_open,
2404         .read = seq_read,
2405         .llseek = seq_lseek,
2406         .release = seq_release_private,
2407 };
2408
2409 static const struct file_operations ftrace_filter_fops = {
2410         .open = ftrace_filter_open,
2411         .read = seq_read,
2412         .write = ftrace_filter_write,
2413         .llseek = ftrace_regex_lseek,
2414         .release = ftrace_filter_release,
2415 };
2416
2417 static const struct file_operations ftrace_notrace_fops = {
2418         .open = ftrace_notrace_open,
2419         .read = seq_read,
2420         .write = ftrace_notrace_write,
2421         .llseek = ftrace_regex_lseek,
2422         .release = ftrace_notrace_release,
2423 };
2424
2425 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2426
2427 static DEFINE_MUTEX(graph_lock);
2428
2429 int ftrace_graph_count;
2430 int ftrace_graph_filter_enabled;
2431 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2432
2433 static void *
2434 __g_next(struct seq_file *m, loff_t *pos)
2435 {
2436         if (*pos >= ftrace_graph_count)
2437                 return NULL;
2438         return &ftrace_graph_funcs[*pos];
2439 }
2440
2441 static void *
2442 g_next(struct seq_file *m, void *v, loff_t *pos)
2443 {
2444         (*pos)++;
2445         return __g_next(m, pos);
2446 }
2447
2448 static void *g_start(struct seq_file *m, loff_t *pos)
2449 {
2450         mutex_lock(&graph_lock);
2451
2452         /* Nothing, tell g_show to print all functions are enabled */
2453         if (!ftrace_graph_filter_enabled && !*pos)
2454                 return (void *)1;
2455
2456         return __g_next(m, pos);
2457 }
2458
2459 static void g_stop(struct seq_file *m, void *p)
2460 {
2461         mutex_unlock(&graph_lock);
2462 }
2463
2464 static int g_show(struct seq_file *m, void *v)
2465 {
2466         unsigned long *ptr = v;
2467
2468         if (!ptr)
2469                 return 0;
2470
2471         if (ptr == (unsigned long *)1) {
2472                 seq_printf(m, "#### all functions enabled ####\n");
2473                 return 0;
2474         }
2475
2476         seq_printf(m, "%ps\n", (void *)*ptr);
2477
2478         return 0;
2479 }
2480
2481 static const struct seq_operations ftrace_graph_seq_ops = {
2482         .start = g_start,
2483         .next = g_next,
2484         .stop = g_stop,
2485         .show = g_show,
2486 };
2487
2488 static int
2489 ftrace_graph_open(struct inode *inode, struct file *file)
2490 {
2491         int ret = 0;
2492
2493         if (unlikely(ftrace_disabled))
2494                 return -ENODEV;
2495
2496         mutex_lock(&graph_lock);
2497         if ((file->f_mode & FMODE_WRITE) &&
2498             (file->f_flags & O_TRUNC)) {
2499                 ftrace_graph_filter_enabled = 0;
2500                 ftrace_graph_count = 0;
2501                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2502         }
2503         mutex_unlock(&graph_lock);
2504
2505         if (file->f_mode & FMODE_READ)
2506                 ret = seq_open(file, &ftrace_graph_seq_ops);
2507
2508         return ret;
2509 }
2510
2511 static int
2512 ftrace_graph_release(struct inode *inode, struct file *file)
2513 {
2514         if (file->f_mode & FMODE_READ)
2515                 seq_release(inode, file);
2516         return 0;
2517 }
2518
2519 static int
2520 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2521 {
2522         struct dyn_ftrace *rec;
2523         struct ftrace_page *pg;
2524         int search_len;
2525         int fail = 1;
2526         int type, not;
2527         char *search;
2528         bool exists;
2529         int i;
2530
2531         if (ftrace_disabled)
2532                 return -ENODEV;
2533
2534         /* decode regex */
2535         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
2536         if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
2537                 return -EBUSY;
2538
2539         search_len = strlen(search);
2540
2541         mutex_lock(&ftrace_lock);
2542         do_for_each_ftrace_rec(pg, rec) {
2543
2544                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2545                         continue;
2546
2547                 if (ftrace_match_record(rec, search, search_len, type)) {
2548                         /* if it is in the array */
2549                         exists = false;
2550                         for (i = 0; i < *idx; i++) {
2551                                 if (array[i] == rec->ip) {
2552                                         exists = true;
2553                                         break;
2554                                 }
2555                         }
2556
2557                         if (!not) {
2558                                 fail = 0;
2559                                 if (!exists) {
2560                                         array[(*idx)++] = rec->ip;
2561                                         if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2562                                                 goto out;
2563                                 }
2564                         } else {
2565                                 if (exists) {
2566                                         array[i] = array[--(*idx)];
2567                                         array[*idx] = 0;
2568                                         fail = 0;
2569                                 }
2570                         }
2571                 }
2572         } while_for_each_ftrace_rec();
2573 out:
2574         mutex_unlock(&ftrace_lock);
2575
2576         if (fail)
2577                 return -EINVAL;
2578
2579         ftrace_graph_filter_enabled = 1;
2580         return 0;
2581 }
2582
2583 static ssize_t
2584 ftrace_graph_write(struct file *file, const char __user *ubuf,
2585                    size_t cnt, loff_t *ppos)
2586 {
2587         struct trace_parser parser;
2588         ssize_t read, ret;
2589
2590         if (!cnt)
2591                 return 0;
2592
2593         mutex_lock(&graph_lock);
2594
2595         if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2596                 ret = -ENOMEM;
2597                 goto out_unlock;
2598         }
2599
2600         read = trace_get_user(&parser, ubuf, cnt, ppos);
2601
2602         if (read >= 0 && trace_parser_loaded((&parser))) {
2603                 parser.buffer[parser.idx] = 0;
2604
2605                 /* we allow only one expression at a time */
2606                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2607                                         parser.buffer);
2608                 if (ret)
2609                         goto out_free;
2610         }
2611
2612         ret = read;
2613
2614 out_free:
2615         trace_parser_put(&parser);
2616 out_unlock:
2617         mutex_unlock(&graph_lock);
2618
2619         return ret;
2620 }
2621
2622 static const struct file_operations ftrace_graph_fops = {
2623         .open           = ftrace_graph_open,
2624         .read           = seq_read,
2625         .write          = ftrace_graph_write,
2626         .release        = ftrace_graph_release,
2627 };
2628 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2629
2630 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2631 {
2632
2633         trace_create_file("available_filter_functions", 0444,
2634                         d_tracer, NULL, &ftrace_avail_fops);
2635
2636         trace_create_file("failures", 0444,
2637                         d_tracer, NULL, &ftrace_failures_fops);
2638
2639         trace_create_file("set_ftrace_filter", 0644, d_tracer,
2640                         NULL, &ftrace_filter_fops);
2641
2642         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2643                                     NULL, &ftrace_notrace_fops);
2644
2645 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2646         trace_create_file("set_graph_function", 0444, d_tracer,
2647                                     NULL,
2648                                     &ftrace_graph_fops);
2649 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2650
2651         return 0;
2652 }
2653
2654 static int ftrace_process_locs(struct module *mod,
2655                                unsigned long *start,
2656                                unsigned long *end)
2657 {
2658         unsigned long *p;
2659         unsigned long addr;
2660         unsigned long flags;
2661
2662         mutex_lock(&ftrace_lock);
2663         p = start;
2664         while (p < end) {
2665                 addr = ftrace_call_adjust(*p++);
2666                 /*
2667                  * Some architecture linkers will pad between
2668                  * the different mcount_loc sections of different
2669                  * object files to satisfy alignments.
2670                  * Skip any NULL pointers.
2671                  */
2672                 if (!addr)
2673                         continue;
2674                 ftrace_record_ip(addr);
2675         }
2676
2677         /* disable interrupts to prevent kstop machine */
2678         local_irq_save(flags);
2679         ftrace_update_code(mod);
2680         local_irq_restore(flags);
2681         mutex_unlock(&ftrace_lock);
2682
2683         return 0;
2684 }
2685
2686 #ifdef CONFIG_MODULES
2687 void ftrace_release_mod(struct module *mod)
2688 {
2689         struct dyn_ftrace *rec;
2690         struct ftrace_page *pg;
2691
2692         if (ftrace_disabled)
2693                 return;
2694
2695         mutex_lock(&ftrace_lock);
2696         do_for_each_ftrace_rec(pg, rec) {
2697                 if (within_module_core(rec->ip, mod)) {
2698                         /*
2699                          * rec->ip is changed in ftrace_free_rec()
2700                          * It should not between s and e if record was freed.
2701                          */
2702                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2703                         ftrace_free_rec(rec);
2704                 }
2705         } while_for_each_ftrace_rec();
2706         mutex_unlock(&ftrace_lock);
2707 }
2708
2709 static void ftrace_init_module(struct module *mod,
2710                                unsigned long *start, unsigned long *end)
2711 {
2712         if (ftrace_disabled || start == end)
2713                 return;
2714         ftrace_process_locs(mod, start, end);
2715 }
2716
2717 static int ftrace_module_notify(struct notifier_block *self,
2718                                 unsigned long val, void *data)
2719 {
2720         struct module *mod = data;
2721
2722         switch (val) {
2723         case MODULE_STATE_COMING:
2724                 ftrace_init_module(mod, mod->ftrace_callsites,
2725                                    mod->ftrace_callsites +
2726                                    mod->num_ftrace_callsites);
2727                 break;
2728         case MODULE_STATE_GOING:
2729                 ftrace_release_mod(mod);
2730                 break;
2731         }
2732
2733         return 0;
2734 }
2735 #else
2736 static int ftrace_module_notify(struct notifier_block *self,
2737                                 unsigned long val, void *data)
2738 {
2739         return 0;
2740 }
2741 #endif /* CONFIG_MODULES */
2742
2743 struct notifier_block ftrace_module_nb = {
2744         .notifier_call = ftrace_module_notify,
2745         .priority = 0,
2746 };
2747
2748 extern unsigned long __start_mcount_loc[];
2749 extern unsigned long __stop_mcount_loc[];
2750
2751 void __init ftrace_init(void)
2752 {
2753         unsigned long count, addr, flags;
2754         int ret;
2755
2756         /* Keep the ftrace pointer to the stub */
2757         addr = (unsigned long)ftrace_stub;
2758
2759         local_irq_save(flags);
2760         ftrace_dyn_arch_init(&addr);
2761         local_irq_restore(flags);
2762
2763         /* ftrace_dyn_arch_init places the return code in addr */
2764         if (addr)
2765                 goto failed;
2766
2767         count = __stop_mcount_loc - __start_mcount_loc;
2768
2769         ret = ftrace_dyn_table_alloc(count);
2770         if (ret)
2771                 goto failed;
2772
2773         last_ftrace_enabled = ftrace_enabled = 1;
2774
2775         ret = ftrace_process_locs(NULL,
2776                                   __start_mcount_loc,
2777                                   __stop_mcount_loc);
2778
2779         ret = register_module_notifier(&ftrace_module_nb);
2780         if (ret)
2781                 pr_warning("Failed to register trace ftrace module notifier\n");
2782
2783         set_ftrace_early_filters();
2784
2785         return;
2786  failed:
2787         ftrace_disabled = 1;
2788 }
2789
2790 #else
2791
2792 static int __init ftrace_nodyn_init(void)
2793 {
2794         ftrace_enabled = 1;
2795         return 0;
2796 }
2797 device_initcall(ftrace_nodyn_init);
2798
2799 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2800 static inline void ftrace_startup_enable(int command) { }
2801 /* Keep as macros so we do not need to define the commands */
2802 # define ftrace_startup(command)        do { } while (0)
2803 # define ftrace_shutdown(command)       do { } while (0)
2804 # define ftrace_startup_sysctl()        do { } while (0)
2805 # define ftrace_shutdown_sysctl()       do { } while (0)
2806 #endif /* CONFIG_DYNAMIC_FTRACE */
2807
2808 static void clear_ftrace_swapper(void)
2809 {
2810         struct task_struct *p;
2811         int cpu;
2812
2813         get_online_cpus();
2814         for_each_online_cpu(cpu) {
2815                 p = idle_task(cpu);
2816                 clear_tsk_trace_trace(p);
2817         }
2818         put_online_cpus();
2819 }
2820
2821 static void set_ftrace_swapper(void)
2822 {
2823         struct task_struct *p;
2824         int cpu;
2825
2826         get_online_cpus();
2827         for_each_online_cpu(cpu) {
2828                 p = idle_task(cpu);
2829                 set_tsk_trace_trace(p);
2830         }
2831         put_online_cpus();
2832 }
2833
2834 static void clear_ftrace_pid(struct pid *pid)
2835 {
2836         struct task_struct *p;
2837
2838         rcu_read_lock();
2839         do_each_pid_task(pid, PIDTYPE_PID, p) {
2840                 clear_tsk_trace_trace(p);
2841         } while_each_pid_task(pid, PIDTYPE_PID, p);
2842         rcu_read_unlock();
2843
2844         put_pid(pid);
2845 }
2846
2847 static void set_ftrace_pid(struct pid *pid)
2848 {
2849         struct task_struct *p;
2850
2851         rcu_read_lock();
2852         do_each_pid_task(pid, PIDTYPE_PID, p) {
2853                 set_tsk_trace_trace(p);
2854         } while_each_pid_task(pid, PIDTYPE_PID, p);
2855         rcu_read_unlock();
2856 }
2857
2858 static void clear_ftrace_pid_task(struct pid *pid)
2859 {
2860         if (pid == ftrace_swapper_pid)
2861                 clear_ftrace_swapper();
2862         else
2863                 clear_ftrace_pid(pid);
2864 }
2865
2866 static void set_ftrace_pid_task(struct pid *pid)
2867 {
2868         if (pid == ftrace_swapper_pid)
2869                 set_ftrace_swapper();
2870         else
2871                 set_ftrace_pid(pid);
2872 }
2873
2874 static int ftrace_pid_add(int p)
2875 {
2876         struct pid *pid;
2877         struct ftrace_pid *fpid;
2878         int ret = -EINVAL;
2879
2880         mutex_lock(&ftrace_lock);
2881
2882         if (!p)
2883                 pid = ftrace_swapper_pid;
2884         else
2885                 pid = find_get_pid(p);
2886
2887         if (!pid)
2888                 goto out;
2889
2890         ret = 0;
2891
2892         list_for_each_entry(fpid, &ftrace_pids, list)
2893                 if (fpid->pid == pid)
2894                         goto out_put;
2895
2896         ret = -ENOMEM;
2897
2898         fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2899         if (!fpid)
2900                 goto out_put;
2901
2902         list_add(&fpid->list, &ftrace_pids);
2903         fpid->pid = pid;
2904
2905         set_ftrace_pid_task(pid);
2906
2907         ftrace_update_pid_func();
2908         ftrace_startup_enable(0);
2909
2910         mutex_unlock(&ftrace_lock);
2911         return 0;
2912
2913 out_put:
2914         if (pid != ftrace_swapper_pid)
2915                 put_pid(pid);
2916
2917 out:
2918         mutex_unlock(&ftrace_lock);
2919         return ret;
2920 }
2921
2922 static void ftrace_pid_reset(void)
2923 {
2924         struct ftrace_pid *fpid, *safe;
2925
2926         mutex_lock(&ftrace_lock);
2927         list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2928                 struct pid *pid = fpid->pid;
2929
2930                 clear_ftrace_pid_task(pid);
2931
2932                 list_del(&fpid->list);
2933                 kfree(fpid);
2934         }
2935
2936         ftrace_update_pid_func();
2937         ftrace_startup_enable(0);
2938
2939         mutex_unlock(&ftrace_lock);
2940 }
2941
2942 static void *fpid_start(struct seq_file *m, loff_t *pos)
2943 {
2944         mutex_lock(&ftrace_lock);
2945
2946         if (list_empty(&ftrace_pids) && (!*pos))
2947                 return (void *) 1;
2948
2949         return seq_list_start(&ftrace_pids, *pos);
2950 }
2951
2952 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
2953 {
2954         if (v == (void *)1)
2955                 return NULL;
2956
2957         return seq_list_next(v, &ftrace_pids, pos);
2958 }
2959
2960 static void fpid_stop(struct seq_file *m, void *p)
2961 {
2962         mutex_unlock(&ftrace_lock);
2963 }
2964
2965 static int fpid_show(struct seq_file *m, void *v)
2966 {
2967         const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
2968
2969         if (v == (void *)1) {
2970                 seq_printf(m, "no pid\n");
2971                 return 0;
2972         }
2973
2974         if (fpid->pid == ftrace_swapper_pid)
2975                 seq_printf(m, "swapper tasks\n");
2976         else
2977                 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
2978
2979         return 0;
2980 }
2981
2982 static const struct seq_operations ftrace_pid_sops = {
2983         .start = fpid_start,
2984         .next = fpid_next,
2985         .stop = fpid_stop,
2986         .show = fpid_show,
2987 };
2988
2989 static int
2990 ftrace_pid_open(struct inode *inode, struct file *file)
2991 {
2992         int ret = 0;
2993
2994         if ((file->f_mode & FMODE_WRITE) &&
2995             (file->f_flags & O_TRUNC))
2996                 ftrace_pid_reset();
2997
2998         if (file->f_mode & FMODE_READ)
2999                 ret = seq_open(file, &ftrace_pid_sops);
3000
3001         return ret;
3002 }
3003
3004 static ssize_t
3005 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3006                    size_t cnt, loff_t *ppos)
3007 {
3008         char buf[64], *tmp;
3009         long val;
3010         int ret;
3011
3012         if (cnt >= sizeof(buf))
3013                 return -EINVAL;
3014
3015         if (copy_from_user(&buf, ubuf, cnt))
3016                 return -EFAULT;
3017
3018         buf[cnt] = 0;
3019
3020         /*
3021          * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3022          * to clean the filter quietly.
3023          */
3024         tmp = strstrip(buf);
3025         if (strlen(tmp) == 0)
3026                 return 1;
3027
3028         ret = strict_strtol(tmp, 10, &val);
3029         if (ret < 0)
3030                 return ret;
3031
3032         ret = ftrace_pid_add(val);
3033
3034         return ret ? ret : cnt;
3035 }
3036
3037 static int
3038 ftrace_pid_release(struct inode *inode, struct file *file)
3039 {
3040         if (file->f_mode & FMODE_READ)
3041                 seq_release(inode, file);
3042
3043         return 0;
3044 }
3045
3046 static const struct file_operations ftrace_pid_fops = {
3047         .open           = ftrace_pid_open,
3048         .write          = ftrace_pid_write,
3049         .read           = seq_read,
3050         .llseek         = seq_lseek,
3051         .release        = ftrace_pid_release,
3052 };
3053
3054 static __init int ftrace_init_debugfs(void)
3055 {
3056         struct dentry *d_tracer;
3057
3058         d_tracer = tracing_init_dentry();
3059         if (!d_tracer)
3060                 return 0;
3061
3062         ftrace_init_dyn_debugfs(d_tracer);
3063
3064         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3065                             NULL, &ftrace_pid_fops);
3066
3067         ftrace_profile_debugfs(d_tracer);
3068
3069         return 0;
3070 }
3071 fs_initcall(ftrace_init_debugfs);
3072
3073 /**
3074  * ftrace_kill - kill ftrace
3075  *
3076  * This function should be used by panic code. It stops ftrace
3077  * but in a not so nice way. If you need to simply kill ftrace
3078  * from a non-atomic section, use ftrace_kill.
3079  */
3080 void ftrace_kill(void)
3081 {
3082         ftrace_disabled = 1;
3083         ftrace_enabled = 0;
3084         clear_ftrace_function();
3085 }
3086
3087 /**
3088  * register_ftrace_function - register a function for profiling
3089  * @ops - ops structure that holds the function for profiling.
3090  *
3091  * Register a function to be called by all functions in the
3092  * kernel.
3093  *
3094  * Note: @ops->func and all the functions it calls must be labeled
3095  *       with "notrace", otherwise it will go into a
3096  *       recursive loop.
3097  */
3098 int register_ftrace_function(struct ftrace_ops *ops)
3099 {
3100         int ret;
3101
3102         if (unlikely(ftrace_disabled))
3103                 return -1;
3104
3105         mutex_lock(&ftrace_lock);
3106
3107         ret = __register_ftrace_function(ops);
3108         ftrace_startup(0);
3109
3110         mutex_unlock(&ftrace_lock);
3111         return ret;
3112 }
3113
3114 /**
3115  * unregister_ftrace_function - unregister a function for profiling.
3116  * @ops - ops structure that holds the function to unregister
3117  *
3118  * Unregister a function that was added to be called by ftrace profiling.
3119  */
3120 int unregister_ftrace_function(struct ftrace_ops *ops)
3121 {
3122         int ret;
3123
3124         mutex_lock(&ftrace_lock);
3125         ret = __unregister_ftrace_function(ops);
3126         ftrace_shutdown(0);
3127         mutex_unlock(&ftrace_lock);
3128
3129         return ret;
3130 }
3131
3132 int
3133 ftrace_enable_sysctl(struct ctl_table *table, int write,
3134                      void __user *buffer, size_t *lenp,
3135                      loff_t *ppos)
3136 {
3137         int ret;
3138
3139         if (unlikely(ftrace_disabled))
3140                 return -ENODEV;
3141
3142         mutex_lock(&ftrace_lock);
3143
3144         ret  = proc_dointvec(table, write, buffer, lenp, ppos);
3145
3146         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3147                 goto out;
3148
3149         last_ftrace_enabled = !!ftrace_enabled;
3150
3151         if (ftrace_enabled) {
3152
3153                 ftrace_startup_sysctl();
3154
3155                 /* we are starting ftrace again */
3156                 if (ftrace_list != &ftrace_list_end) {
3157                         if (ftrace_list->next == &ftrace_list_end)
3158                                 ftrace_trace_function = ftrace_list->func;
3159                         else
3160                                 ftrace_trace_function = ftrace_list_func;
3161                 }
3162
3163         } else {
3164                 /* stopping ftrace calls (just send to ftrace_stub) */
3165                 ftrace_trace_function = ftrace_stub;
3166
3167                 ftrace_shutdown_sysctl();
3168         }
3169
3170  out:
3171         mutex_unlock(&ftrace_lock);
3172         return ret;
3173 }
3174
3175 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3176
3177 static int ftrace_graph_active;
3178 static struct notifier_block ftrace_suspend_notifier;
3179
3180 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3181 {
3182         return 0;
3183 }
3184
3185 /* The callbacks that hook a function */
3186 trace_func_graph_ret_t ftrace_graph_return =
3187                         (trace_func_graph_ret_t)ftrace_stub;
3188 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3189
3190 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3191 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3192 {
3193         int i;
3194         int ret = 0;
3195         unsigned long flags;
3196         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3197         struct task_struct *g, *t;
3198
3199         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3200                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3201                                         * sizeof(struct ftrace_ret_stack),
3202                                         GFP_KERNEL);
3203                 if (!ret_stack_list[i]) {
3204                         start = 0;
3205                         end = i;
3206                         ret = -ENOMEM;
3207                         goto free;
3208                 }
3209         }
3210
3211         read_lock_irqsave(&tasklist_lock, flags);
3212         do_each_thread(g, t) {
3213                 if (start == end) {
3214                         ret = -EAGAIN;
3215                         goto unlock;
3216                 }
3217
3218                 if (t->ret_stack == NULL) {
3219                         atomic_set(&t->tracing_graph_pause, 0);
3220                         atomic_set(&t->trace_overrun, 0);
3221                         t->curr_ret_stack = -1;
3222                         /* Make sure the tasks see the -1 first: */
3223                         smp_wmb();
3224                         t->ret_stack = ret_stack_list[start++];
3225                 }
3226         } while_each_thread(g, t);
3227
3228 unlock:
3229         read_unlock_irqrestore(&tasklist_lock, flags);
3230 free:
3231         for (i = start; i < end; i++)
3232                 kfree(ret_stack_list[i]);
3233         return ret;
3234 }
3235
3236 static void
3237 ftrace_graph_probe_sched_switch(struct task_struct *prev, struct task_struct *next)
3238 {
3239         unsigned long long timestamp;
3240         int index;
3241
3242         /*
3243          * Does the user want to count the time a function was asleep.
3244          * If so, do not update the time stamps.
3245          */
3246         if (trace_flags & TRACE_ITER_SLEEP_TIME)
3247                 return;
3248
3249         timestamp = trace_clock_local();
3250
3251         prev->ftrace_timestamp = timestamp;
3252
3253         /* only process tasks that we timestamped */
3254         if (!next->ftrace_timestamp)
3255                 return;
3256
3257         /*
3258          * Update all the counters in next to make up for the
3259          * time next was sleeping.
3260          */
3261         timestamp -= next->ftrace_timestamp;
3262
3263         for (index = next->curr_ret_stack; index >= 0; index--)
3264                 next->ret_stack[index].calltime += timestamp;
3265 }
3266
3267 /* Allocate a return stack for each task */
3268 static int start_graph_tracing(void)
3269 {
3270         struct ftrace_ret_stack **ret_stack_list;
3271         int ret, cpu;
3272
3273         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3274                                 sizeof(struct ftrace_ret_stack *),
3275                                 GFP_KERNEL);
3276
3277         if (!ret_stack_list)
3278                 return -ENOMEM;
3279
3280         /* The cpu_boot init_task->ret_stack will never be freed */
3281         for_each_online_cpu(cpu) {
3282                 if (!idle_task(cpu)->ret_stack)
3283                         ftrace_graph_init_task(idle_task(cpu));
3284         }
3285
3286         do {
3287                 ret = alloc_retstack_tasklist(ret_stack_list);
3288         } while (ret == -EAGAIN);
3289
3290         if (!ret) {
3291                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3292                 if (ret)
3293                         pr_info("ftrace_graph: Couldn't activate tracepoint"
3294                                 " probe to kernel_sched_switch\n");
3295         }
3296
3297         kfree(ret_stack_list);
3298         return ret;
3299 }
3300
3301 /*
3302  * Hibernation protection.
3303  * The state of the current task is too much unstable during
3304  * suspend/restore to disk. We want to protect against that.
3305  */
3306 static int
3307 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3308                                                         void *unused)
3309 {
3310         switch (state) {
3311         case PM_HIBERNATION_PREPARE:
3312                 pause_graph_tracing();
3313                 break;
3314
3315         case PM_POST_HIBERNATION:
3316                 unpause_graph_tracing();
3317                 break;
3318         }
3319         return NOTIFY_DONE;
3320 }
3321
3322 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3323                         trace_func_graph_ent_t entryfunc)
3324 {
3325         int ret = 0;
3326
3327         mutex_lock(&ftrace_lock);
3328
3329         /* we currently allow only one tracer registered at a time */
3330         if (ftrace_graph_active) {
3331                 ret = -EBUSY;
3332                 goto out;
3333         }
3334
3335         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3336         register_pm_notifier(&ftrace_suspend_notifier);
3337
3338         ftrace_graph_active++;
3339         ret = start_graph_tracing();
3340         if (ret) {
3341                 ftrace_graph_active--;
3342                 goto out;
3343         }
3344
3345         ftrace_graph_return = retfunc;
3346         ftrace_graph_entry = entryfunc;
3347
3348         ftrace_startup(FTRACE_START_FUNC_RET);
3349
3350 out:
3351         mutex_unlock(&ftrace_lock);
3352         return ret;
3353 }
3354
3355 void unregister_ftrace_graph(void)
3356 {
3357         mutex_lock(&ftrace_lock);
3358
3359         if (unlikely(!ftrace_graph_active))
3360                 goto out;
3361
3362         ftrace_graph_active--;
3363         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3364         ftrace_graph_entry = ftrace_graph_entry_stub;
3365         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3366         unregister_pm_notifier(&ftrace_suspend_notifier);
3367         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3368
3369  out:
3370         mutex_unlock(&ftrace_lock);
3371 }
3372
3373 /* Allocate a return stack for newly created task */
3374 void ftrace_graph_init_task(struct task_struct *t)
3375 {
3376         /* Make sure we do not use the parent ret_stack */
3377         t->ret_stack = NULL;
3378         t->curr_ret_stack = -1;
3379
3380         if (ftrace_graph_active) {
3381                 struct ftrace_ret_stack *ret_stack;
3382
3383                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3384                                 * sizeof(struct ftrace_ret_stack),
3385                                 GFP_KERNEL);
3386                 if (!ret_stack)
3387                         return;
3388                 atomic_set(&t->tracing_graph_pause, 0);
3389                 atomic_set(&t->trace_overrun, 0);
3390                 t->ftrace_timestamp = 0;
3391                 /* make curr_ret_stack visable before we add the ret_stack */
3392                 smp_wmb();
3393                 t->ret_stack = ret_stack;
3394         }
3395 }
3396
3397 void ftrace_graph_exit_task(struct task_struct *t)
3398 {
3399         struct ftrace_ret_stack *ret_stack = t->ret_stack;
3400
3401         t->ret_stack = NULL;
3402         /* NULL must become visible to IRQs before we free it: */
3403         barrier();
3404
3405         kfree(ret_stack);
3406 }
3407
3408 void ftrace_graph_stop(void)
3409 {
3410         ftrace_stop();
3411 }
3412 #endif