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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/module.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/slab.h>
29 #include <linux/ctype.h>
30 #include <linux/list.h>
31 #include <linux/hash.h>
32 #include <linux/rcupdate.h>
33
34 #include <trace/events/sched.h>
35
36 #include <asm/setup.h>
37
38 #include "trace_output.h"
39 #include "trace_stat.h"
40
41 #define FTRACE_WARN_ON(cond)                    \
42         ({                                      \
43                 int ___r = cond;                \
44                 if (WARN_ON(___r))              \
45                         ftrace_kill();          \
46                 ___r;                           \
47         })
48
49 #define FTRACE_WARN_ON_ONCE(cond)               \
50         ({                                      \
51                 int ___r = cond;                \
52                 if (WARN_ON_ONCE(___r))         \
53                         ftrace_kill();          \
54                 ___r;                           \
55         })
56
57 /* hash bits for specific function selection */
58 #define FTRACE_HASH_BITS 7
59 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
60 #define FTRACE_HASH_DEFAULT_BITS 10
61 #define FTRACE_HASH_MAX_BITS 12
62
63 /* ftrace_enabled is a method to turn ftrace on or off */
64 int ftrace_enabled __read_mostly;
65 static int last_ftrace_enabled;
66
67 /* Quick disabling of function tracer. */
68 int function_trace_stop;
69
70 /* List for set_ftrace_pid's pids. */
71 LIST_HEAD(ftrace_pids);
72 struct ftrace_pid {
73         struct list_head list;
74         struct pid *pid;
75 };
76
77 /*
78  * ftrace_disabled is set when an anomaly is discovered.
79  * ftrace_disabled is much stronger than ftrace_enabled.
80  */
81 static int ftrace_disabled __read_mostly;
82
83 static DEFINE_MUTEX(ftrace_lock);
84
85 static struct ftrace_ops ftrace_list_end __read_mostly = {
86         .func           = ftrace_stub,
87 };
88
89 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
90 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
91 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
92 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
93 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
94 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
95 static struct ftrace_ops global_ops;
96
97 static void
98 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
99
100 /*
101  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
102  * can use rcu_dereference_raw() is that elements removed from this list
103  * are simply leaked, so there is no need to interact with a grace-period
104  * mechanism.  The rcu_dereference_raw() calls are needed to handle
105  * concurrent insertions into the ftrace_global_list.
106  *
107  * Silly Alpha and silly pointer-speculation compiler optimizations!
108  */
109 static void ftrace_global_list_func(unsigned long ip,
110                                     unsigned long parent_ip)
111 {
112         struct ftrace_ops *op;
113
114         if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
115                 return;
116
117         trace_recursion_set(TRACE_GLOBAL_BIT);
118         op = rcu_dereference_raw(ftrace_global_list); /*see above*/
119         while (op != &ftrace_list_end) {
120                 op->func(ip, parent_ip);
121                 op = rcu_dereference_raw(op->next); /*see above*/
122         };
123         trace_recursion_clear(TRACE_GLOBAL_BIT);
124 }
125
126 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
127 {
128         if (!test_tsk_trace_trace(current))
129                 return;
130
131         ftrace_pid_function(ip, parent_ip);
132 }
133
134 static void set_ftrace_pid_function(ftrace_func_t func)
135 {
136         /* do not set ftrace_pid_function to itself! */
137         if (func != ftrace_pid_func)
138                 ftrace_pid_function = func;
139 }
140
141 /**
142  * clear_ftrace_function - reset the ftrace function
143  *
144  * This NULLs the ftrace function and in essence stops
145  * tracing.  There may be lag
146  */
147 void clear_ftrace_function(void)
148 {
149         ftrace_trace_function = ftrace_stub;
150         __ftrace_trace_function = ftrace_stub;
151         __ftrace_trace_function_delay = ftrace_stub;
152         ftrace_pid_function = ftrace_stub;
153 }
154
155 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
156 /*
157  * For those archs that do not test ftrace_trace_stop in their
158  * mcount call site, we need to do it from C.
159  */
160 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
161 {
162         if (function_trace_stop)
163                 return;
164
165         __ftrace_trace_function(ip, parent_ip);
166 }
167 #endif
168
169 static void update_global_ops(void)
170 {
171         ftrace_func_t func;
172
173         /*
174          * If there's only one function registered, then call that
175          * function directly. Otherwise, we need to iterate over the
176          * registered callers.
177          */
178         if (ftrace_global_list == &ftrace_list_end ||
179             ftrace_global_list->next == &ftrace_list_end)
180                 func = ftrace_global_list->func;
181         else
182                 func = ftrace_global_list_func;
183
184         /* If we filter on pids, update to use the pid function */
185         if (!list_empty(&ftrace_pids)) {
186                 set_ftrace_pid_function(func);
187                 func = ftrace_pid_func;
188         }
189
190         global_ops.func = func;
191 }
192
193 static void update_ftrace_function(void)
194 {
195         ftrace_func_t func;
196
197         update_global_ops();
198
199         /*
200          * If we are at the end of the list and this ops is
201          * not dynamic, then have the mcount trampoline call
202          * the function directly
203          */
204         if (ftrace_ops_list == &ftrace_list_end ||
205             (ftrace_ops_list->next == &ftrace_list_end &&
206              !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
207                 func = ftrace_ops_list->func;
208         else
209                 func = ftrace_ops_list_func;
210
211 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
212         ftrace_trace_function = func;
213 #else
214 #ifdef CONFIG_DYNAMIC_FTRACE
215         /* do not update till all functions have been modified */
216         __ftrace_trace_function_delay = func;
217 #else
218         __ftrace_trace_function = func;
219 #endif
220         ftrace_trace_function = ftrace_test_stop_func;
221 #endif
222 }
223
224 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
225 {
226         ops->next = *list;
227         /*
228          * We are entering ops into the list but another
229          * CPU might be walking that list. We need to make sure
230          * the ops->next pointer is valid before another CPU sees
231          * the ops pointer included into the list.
232          */
233         rcu_assign_pointer(*list, ops);
234 }
235
236 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
237 {
238         struct ftrace_ops **p;
239
240         /*
241          * If we are removing the last function, then simply point
242          * to the ftrace_stub.
243          */
244         if (*list == ops && ops->next == &ftrace_list_end) {
245                 *list = &ftrace_list_end;
246                 return 0;
247         }
248
249         for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
250                 if (*p == ops)
251                         break;
252
253         if (*p != ops)
254                 return -1;
255
256         *p = (*p)->next;
257         return 0;
258 }
259
260 static int __register_ftrace_function(struct ftrace_ops *ops)
261 {
262         if (ftrace_disabled)
263                 return -ENODEV;
264
265         if (FTRACE_WARN_ON(ops == &global_ops))
266                 return -EINVAL;
267
268         if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
269                 return -EBUSY;
270
271         if (!core_kernel_data((unsigned long)ops))
272                 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
273
274         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
275                 int first = ftrace_global_list == &ftrace_list_end;
276                 add_ftrace_ops(&ftrace_global_list, ops);
277                 ops->flags |= FTRACE_OPS_FL_ENABLED;
278                 if (first)
279                         add_ftrace_ops(&ftrace_ops_list, &global_ops);
280         } else
281                 add_ftrace_ops(&ftrace_ops_list, ops);
282
283         if (ftrace_enabled)
284                 update_ftrace_function();
285
286         return 0;
287 }
288
289 static int __unregister_ftrace_function(struct ftrace_ops *ops)
290 {
291         int ret;
292
293         if (ftrace_disabled)
294                 return -ENODEV;
295
296         if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
297                 return -EBUSY;
298
299         if (FTRACE_WARN_ON(ops == &global_ops))
300                 return -EINVAL;
301
302         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
303                 ret = remove_ftrace_ops(&ftrace_global_list, ops);
304                 if (!ret && ftrace_global_list == &ftrace_list_end)
305                         ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
306                 if (!ret)
307                         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
308         } else
309                 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
310
311         if (ret < 0)
312                 return ret;
313
314         if (ftrace_enabled)
315                 update_ftrace_function();
316
317         /*
318          * Dynamic ops may be freed, we must make sure that all
319          * callers are done before leaving this function.
320          */
321         if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
322                 synchronize_sched();
323
324         return 0;
325 }
326
327 static void ftrace_update_pid_func(void)
328 {
329         /* Only do something if we are tracing something */
330         if (ftrace_trace_function == ftrace_stub)
331                 return;
332
333         update_ftrace_function();
334 }
335
336 #ifdef CONFIG_FUNCTION_PROFILER
337 struct ftrace_profile {
338         struct hlist_node               node;
339         unsigned long                   ip;
340         unsigned long                   counter;
341 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
342         unsigned long long              time;
343         unsigned long long              time_squared;
344 #endif
345 };
346
347 struct ftrace_profile_page {
348         struct ftrace_profile_page      *next;
349         unsigned long                   index;
350         struct ftrace_profile           records[];
351 };
352
353 struct ftrace_profile_stat {
354         atomic_t                        disabled;
355         struct hlist_head               *hash;
356         struct ftrace_profile_page      *pages;
357         struct ftrace_profile_page      *start;
358         struct tracer_stat              stat;
359 };
360
361 #define PROFILE_RECORDS_SIZE                                            \
362         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
363
364 #define PROFILES_PER_PAGE                                       \
365         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
366
367 static int ftrace_profile_bits __read_mostly;
368 static int ftrace_profile_enabled __read_mostly;
369
370 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
371 static DEFINE_MUTEX(ftrace_profile_lock);
372
373 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
374
375 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
376
377 static void *
378 function_stat_next(void *v, int idx)
379 {
380         struct ftrace_profile *rec = v;
381         struct ftrace_profile_page *pg;
382
383         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
384
385  again:
386         if (idx != 0)
387                 rec++;
388
389         if ((void *)rec >= (void *)&pg->records[pg->index]) {
390                 pg = pg->next;
391                 if (!pg)
392                         return NULL;
393                 rec = &pg->records[0];
394                 if (!rec->counter)
395                         goto again;
396         }
397
398         return rec;
399 }
400
401 static void *function_stat_start(struct tracer_stat *trace)
402 {
403         struct ftrace_profile_stat *stat =
404                 container_of(trace, struct ftrace_profile_stat, stat);
405
406         if (!stat || !stat->start)
407                 return NULL;
408
409         return function_stat_next(&stat->start->records[0], 0);
410 }
411
412 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
413 /* function graph compares on total time */
414 static int function_stat_cmp(void *p1, void *p2)
415 {
416         struct ftrace_profile *a = p1;
417         struct ftrace_profile *b = p2;
418
419         if (a->time < b->time)
420                 return -1;
421         if (a->time > b->time)
422                 return 1;
423         else
424                 return 0;
425 }
426 #else
427 /* not function graph compares against hits */
428 static int function_stat_cmp(void *p1, void *p2)
429 {
430         struct ftrace_profile *a = p1;
431         struct ftrace_profile *b = p2;
432
433         if (a->counter < b->counter)
434                 return -1;
435         if (a->counter > b->counter)
436                 return 1;
437         else
438                 return 0;
439 }
440 #endif
441
442 static int function_stat_headers(struct seq_file *m)
443 {
444 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
445         seq_printf(m, "  Function                               "
446                    "Hit    Time            Avg             s^2\n"
447                       "  --------                               "
448                    "---    ----            ---             ---\n");
449 #else
450         seq_printf(m, "  Function                               Hit\n"
451                       "  --------                               ---\n");
452 #endif
453         return 0;
454 }
455
456 static int function_stat_show(struct seq_file *m, void *v)
457 {
458         struct ftrace_profile *rec = v;
459         char str[KSYM_SYMBOL_LEN];
460         int ret = 0;
461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
462         static struct trace_seq s;
463         unsigned long long avg;
464         unsigned long long stddev;
465 #endif
466         mutex_lock(&ftrace_profile_lock);
467
468         /* we raced with function_profile_reset() */
469         if (unlikely(rec->counter == 0)) {
470                 ret = -EBUSY;
471                 goto out;
472         }
473
474         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
475         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
476
477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
478         seq_printf(m, "    ");
479         avg = rec->time;
480         do_div(avg, rec->counter);
481
482         /* Sample standard deviation (s^2) */
483         if (rec->counter <= 1)
484                 stddev = 0;
485         else {
486                 stddev = rec->time_squared - rec->counter * avg * avg;
487                 /*
488                  * Divide only 1000 for ns^2 -> us^2 conversion.
489                  * trace_print_graph_duration will divide 1000 again.
490                  */
491                 do_div(stddev, (rec->counter - 1) * 1000);
492         }
493
494         trace_seq_init(&s);
495         trace_print_graph_duration(rec->time, &s);
496         trace_seq_puts(&s, "    ");
497         trace_print_graph_duration(avg, &s);
498         trace_seq_puts(&s, "    ");
499         trace_print_graph_duration(stddev, &s);
500         trace_print_seq(m, &s);
501 #endif
502         seq_putc(m, '\n');
503 out:
504         mutex_unlock(&ftrace_profile_lock);
505
506         return ret;
507 }
508
509 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
510 {
511         struct ftrace_profile_page *pg;
512
513         pg = stat->pages = stat->start;
514
515         while (pg) {
516                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
517                 pg->index = 0;
518                 pg = pg->next;
519         }
520
521         memset(stat->hash, 0,
522                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
523 }
524
525 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
526 {
527         struct ftrace_profile_page *pg;
528         int functions;
529         int pages;
530         int i;
531
532         /* If we already allocated, do nothing */
533         if (stat->pages)
534                 return 0;
535
536         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
537         if (!stat->pages)
538                 return -ENOMEM;
539
540 #ifdef CONFIG_DYNAMIC_FTRACE
541         functions = ftrace_update_tot_cnt;
542 #else
543         /*
544          * We do not know the number of functions that exist because
545          * dynamic tracing is what counts them. With past experience
546          * we have around 20K functions. That should be more than enough.
547          * It is highly unlikely we will execute every function in
548          * the kernel.
549          */
550         functions = 20000;
551 #endif
552
553         pg = stat->start = stat->pages;
554
555         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
556
557         for (i = 0; i < pages; i++) {
558                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
559                 if (!pg->next)
560                         goto out_free;
561                 pg = pg->next;
562         }
563
564         return 0;
565
566  out_free:
567         pg = stat->start;
568         while (pg) {
569                 unsigned long tmp = (unsigned long)pg;
570
571                 pg = pg->next;
572                 free_page(tmp);
573         }
574
575         free_page((unsigned long)stat->pages);
576         stat->pages = NULL;
577         stat->start = NULL;
578
579         return -ENOMEM;
580 }
581
582 static int ftrace_profile_init_cpu(int cpu)
583 {
584         struct ftrace_profile_stat *stat;
585         int size;
586
587         stat = &per_cpu(ftrace_profile_stats, cpu);
588
589         if (stat->hash) {
590                 /* If the profile is already created, simply reset it */
591                 ftrace_profile_reset(stat);
592                 return 0;
593         }
594
595         /*
596          * We are profiling all functions, but usually only a few thousand
597          * functions are hit. We'll make a hash of 1024 items.
598          */
599         size = FTRACE_PROFILE_HASH_SIZE;
600
601         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
602
603         if (!stat->hash)
604                 return -ENOMEM;
605
606         if (!ftrace_profile_bits) {
607                 size--;
608
609                 for (; size; size >>= 1)
610                         ftrace_profile_bits++;
611         }
612
613         /* Preallocate the function profiling pages */
614         if (ftrace_profile_pages_init(stat) < 0) {
615                 kfree(stat->hash);
616                 stat->hash = NULL;
617                 return -ENOMEM;
618         }
619
620         return 0;
621 }
622
623 static int ftrace_profile_init(void)
624 {
625         int cpu;
626         int ret = 0;
627
628         for_each_online_cpu(cpu) {
629                 ret = ftrace_profile_init_cpu(cpu);
630                 if (ret)
631                         break;
632         }
633
634         return ret;
635 }
636
637 /* interrupts must be disabled */
638 static struct ftrace_profile *
639 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
640 {
641         struct ftrace_profile *rec;
642         struct hlist_head *hhd;
643         struct hlist_node *n;
644         unsigned long key;
645
646         key = hash_long(ip, ftrace_profile_bits);
647         hhd = &stat->hash[key];
648
649         if (hlist_empty(hhd))
650                 return NULL;
651
652         hlist_for_each_entry_rcu(rec, n, hhd, node) {
653                 if (rec->ip == ip)
654                         return rec;
655         }
656
657         return NULL;
658 }
659
660 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
661                                struct ftrace_profile *rec)
662 {
663         unsigned long key;
664
665         key = hash_long(rec->ip, ftrace_profile_bits);
666         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
667 }
668
669 /*
670  * The memory is already allocated, this simply finds a new record to use.
671  */
672 static struct ftrace_profile *
673 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
674 {
675         struct ftrace_profile *rec = NULL;
676
677         /* prevent recursion (from NMIs) */
678         if (atomic_inc_return(&stat->disabled) != 1)
679                 goto out;
680
681         /*
682          * Try to find the function again since an NMI
683          * could have added it
684          */
685         rec = ftrace_find_profiled_func(stat, ip);
686         if (rec)
687                 goto out;
688
689         if (stat->pages->index == PROFILES_PER_PAGE) {
690                 if (!stat->pages->next)
691                         goto out;
692                 stat->pages = stat->pages->next;
693         }
694
695         rec = &stat->pages->records[stat->pages->index++];
696         rec->ip = ip;
697         ftrace_add_profile(stat, rec);
698
699  out:
700         atomic_dec(&stat->disabled);
701
702         return rec;
703 }
704
705 static void
706 function_profile_call(unsigned long ip, unsigned long parent_ip)
707 {
708         struct ftrace_profile_stat *stat;
709         struct ftrace_profile *rec;
710         unsigned long flags;
711
712         if (!ftrace_profile_enabled)
713                 return;
714
715         local_irq_save(flags);
716
717         stat = &__get_cpu_var(ftrace_profile_stats);
718         if (!stat->hash || !ftrace_profile_enabled)
719                 goto out;
720
721         rec = ftrace_find_profiled_func(stat, ip);
722         if (!rec) {
723                 rec = ftrace_profile_alloc(stat, ip);
724                 if (!rec)
725                         goto out;
726         }
727
728         rec->counter++;
729  out:
730         local_irq_restore(flags);
731 }
732
733 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
734 static int profile_graph_entry(struct ftrace_graph_ent *trace)
735 {
736         function_profile_call(trace->func, 0);
737         return 1;
738 }
739
740 static void profile_graph_return(struct ftrace_graph_ret *trace)
741 {
742         struct ftrace_profile_stat *stat;
743         unsigned long long calltime;
744         struct ftrace_profile *rec;
745         unsigned long flags;
746
747         local_irq_save(flags);
748         stat = &__get_cpu_var(ftrace_profile_stats);
749         if (!stat->hash || !ftrace_profile_enabled)
750                 goto out;
751
752         /* If the calltime was zero'd ignore it */
753         if (!trace->calltime)
754                 goto out;
755
756         calltime = trace->rettime - trace->calltime;
757
758         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
759                 int index;
760
761                 index = trace->depth;
762
763                 /* Append this call time to the parent time to subtract */
764                 if (index)
765                         current->ret_stack[index - 1].subtime += calltime;
766
767                 if (current->ret_stack[index].subtime < calltime)
768                         calltime -= current->ret_stack[index].subtime;
769                 else
770                         calltime = 0;
771         }
772
773         rec = ftrace_find_profiled_func(stat, trace->func);
774         if (rec) {
775                 rec->time += calltime;
776                 rec->time_squared += calltime * calltime;
777         }
778
779  out:
780         local_irq_restore(flags);
781 }
782
783 static int register_ftrace_profiler(void)
784 {
785         return register_ftrace_graph(&profile_graph_return,
786                                      &profile_graph_entry);
787 }
788
789 static void unregister_ftrace_profiler(void)
790 {
791         unregister_ftrace_graph();
792 }
793 #else
794 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
795         .func           = function_profile_call,
796 };
797
798 static int register_ftrace_profiler(void)
799 {
800         return register_ftrace_function(&ftrace_profile_ops);
801 }
802
803 static void unregister_ftrace_profiler(void)
804 {
805         unregister_ftrace_function(&ftrace_profile_ops);
806 }
807 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
808
809 static ssize_t
810 ftrace_profile_write(struct file *filp, const char __user *ubuf,
811                      size_t cnt, loff_t *ppos)
812 {
813         unsigned long val;
814         int ret;
815
816         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
817         if (ret)
818                 return ret;
819
820         val = !!val;
821
822         mutex_lock(&ftrace_profile_lock);
823         if (ftrace_profile_enabled ^ val) {
824                 if (val) {
825                         ret = ftrace_profile_init();
826                         if (ret < 0) {
827                                 cnt = ret;
828                                 goto out;
829                         }
830
831                         ret = register_ftrace_profiler();
832                         if (ret < 0) {
833                                 cnt = ret;
834                                 goto out;
835                         }
836                         ftrace_profile_enabled = 1;
837                 } else {
838                         ftrace_profile_enabled = 0;
839                         /*
840                          * unregister_ftrace_profiler calls stop_machine
841                          * so this acts like an synchronize_sched.
842                          */
843                         unregister_ftrace_profiler();
844                 }
845         }
846  out:
847         mutex_unlock(&ftrace_profile_lock);
848
849         *ppos += cnt;
850
851         return cnt;
852 }
853
854 static ssize_t
855 ftrace_profile_read(struct file *filp, char __user *ubuf,
856                      size_t cnt, loff_t *ppos)
857 {
858         char buf[64];           /* big enough to hold a number */
859         int r;
860
861         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
862         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
863 }
864
865 static const struct file_operations ftrace_profile_fops = {
866         .open           = tracing_open_generic,
867         .read           = ftrace_profile_read,
868         .write          = ftrace_profile_write,
869         .llseek         = default_llseek,
870 };
871
872 /* used to initialize the real stat files */
873 static struct tracer_stat function_stats __initdata = {
874         .name           = "functions",
875         .stat_start     = function_stat_start,
876         .stat_next      = function_stat_next,
877         .stat_cmp       = function_stat_cmp,
878         .stat_headers   = function_stat_headers,
879         .stat_show      = function_stat_show
880 };
881
882 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
883 {
884         struct ftrace_profile_stat *stat;
885         struct dentry *entry;
886         char *name;
887         int ret;
888         int cpu;
889
890         for_each_possible_cpu(cpu) {
891                 stat = &per_cpu(ftrace_profile_stats, cpu);
892
893                 /* allocate enough for function name + cpu number */
894                 name = kmalloc(32, GFP_KERNEL);
895                 if (!name) {
896                         /*
897                          * The files created are permanent, if something happens
898                          * we still do not free memory.
899                          */
900                         WARN(1,
901                              "Could not allocate stat file for cpu %d\n",
902                              cpu);
903                         return;
904                 }
905                 stat->stat = function_stats;
906                 snprintf(name, 32, "function%d", cpu);
907                 stat->stat.name = name;
908                 ret = register_stat_tracer(&stat->stat);
909                 if (ret) {
910                         WARN(1,
911                              "Could not register function stat for cpu %d\n",
912                              cpu);
913                         kfree(name);
914                         return;
915                 }
916         }
917
918         entry = debugfs_create_file("function_profile_enabled", 0644,
919                                     d_tracer, NULL, &ftrace_profile_fops);
920         if (!entry)
921                 pr_warning("Could not create debugfs "
922                            "'function_profile_enabled' entry\n");
923 }
924
925 #else /* CONFIG_FUNCTION_PROFILER */
926 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
927 {
928 }
929 #endif /* CONFIG_FUNCTION_PROFILER */
930
931 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
932
933 #ifdef CONFIG_DYNAMIC_FTRACE
934
935 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
936 # error Dynamic ftrace depends on MCOUNT_RECORD
937 #endif
938
939 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
940
941 struct ftrace_func_probe {
942         struct hlist_node       node;
943         struct ftrace_probe_ops *ops;
944         unsigned long           flags;
945         unsigned long           ip;
946         void                    *data;
947         struct rcu_head         rcu;
948 };
949
950 enum {
951         FTRACE_ENABLE_CALLS             = (1 << 0),
952         FTRACE_DISABLE_CALLS            = (1 << 1),
953         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
954         FTRACE_START_FUNC_RET           = (1 << 3),
955         FTRACE_STOP_FUNC_RET            = (1 << 4),
956 };
957 struct ftrace_func_entry {
958         struct hlist_node hlist;
959         unsigned long ip;
960 };
961
962 struct ftrace_hash {
963         unsigned long           size_bits;
964         struct hlist_head       *buckets;
965         unsigned long           count;
966         struct rcu_head         rcu;
967 };
968
969 /*
970  * We make these constant because no one should touch them,
971  * but they are used as the default "empty hash", to avoid allocating
972  * it all the time. These are in a read only section such that if
973  * anyone does try to modify it, it will cause an exception.
974  */
975 static const struct hlist_head empty_buckets[1];
976 static const struct ftrace_hash empty_hash = {
977         .buckets = (struct hlist_head *)empty_buckets,
978 };
979 #define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
980
981 static struct ftrace_ops global_ops = {
982         .func                   = ftrace_stub,
983         .notrace_hash           = EMPTY_HASH,
984         .filter_hash            = EMPTY_HASH,
985 };
986
987 static struct dyn_ftrace *ftrace_new_addrs;
988
989 static DEFINE_MUTEX(ftrace_regex_lock);
990
991 struct ftrace_page {
992         struct ftrace_page      *next;
993         int                     index;
994         struct dyn_ftrace       records[];
995 };
996
997 #define ENTRIES_PER_PAGE \
998   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
999
1000 /* estimate from running different kernels */
1001 #define NR_TO_INIT              10000
1002
1003 static struct ftrace_page       *ftrace_pages_start;
1004 static struct ftrace_page       *ftrace_pages;
1005
1006 static struct dyn_ftrace *ftrace_free_records;
1007
1008 static struct ftrace_func_entry *
1009 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1010 {
1011         unsigned long key;
1012         struct ftrace_func_entry *entry;
1013         struct hlist_head *hhd;
1014         struct hlist_node *n;
1015
1016         if (!hash->count)
1017                 return NULL;
1018
1019         if (hash->size_bits > 0)
1020                 key = hash_long(ip, hash->size_bits);
1021         else
1022                 key = 0;
1023
1024         hhd = &hash->buckets[key];
1025
1026         hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1027                 if (entry->ip == ip)
1028                         return entry;
1029         }
1030         return NULL;
1031 }
1032
1033 static void __add_hash_entry(struct ftrace_hash *hash,
1034                              struct ftrace_func_entry *entry)
1035 {
1036         struct hlist_head *hhd;
1037         unsigned long key;
1038
1039         if (hash->size_bits)
1040                 key = hash_long(entry->ip, hash->size_bits);
1041         else
1042                 key = 0;
1043
1044         hhd = &hash->buckets[key];
1045         hlist_add_head(&entry->hlist, hhd);
1046         hash->count++;
1047 }
1048
1049 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1050 {
1051         struct ftrace_func_entry *entry;
1052
1053         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1054         if (!entry)
1055                 return -ENOMEM;
1056
1057         entry->ip = ip;
1058         __add_hash_entry(hash, entry);
1059
1060         return 0;
1061 }
1062
1063 static void
1064 free_hash_entry(struct ftrace_hash *hash,
1065                   struct ftrace_func_entry *entry)
1066 {
1067         hlist_del(&entry->hlist);
1068         kfree(entry);
1069         hash->count--;
1070 }
1071
1072 static void
1073 remove_hash_entry(struct ftrace_hash *hash,
1074                   struct ftrace_func_entry *entry)
1075 {
1076         hlist_del(&entry->hlist);
1077         hash->count--;
1078 }
1079
1080 static void ftrace_hash_clear(struct ftrace_hash *hash)
1081 {
1082         struct hlist_head *hhd;
1083         struct hlist_node *tp, *tn;
1084         struct ftrace_func_entry *entry;
1085         int size = 1 << hash->size_bits;
1086         int i;
1087
1088         if (!hash->count)
1089                 return;
1090
1091         for (i = 0; i < size; i++) {
1092                 hhd = &hash->buckets[i];
1093                 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1094                         free_hash_entry(hash, entry);
1095         }
1096         FTRACE_WARN_ON(hash->count);
1097 }
1098
1099 static void free_ftrace_hash(struct ftrace_hash *hash)
1100 {
1101         if (!hash || hash == EMPTY_HASH)
1102                 return;
1103         ftrace_hash_clear(hash);
1104         kfree(hash->buckets);
1105         kfree(hash);
1106 }
1107
1108 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1109 {
1110         struct ftrace_hash *hash;
1111
1112         hash = container_of(rcu, struct ftrace_hash, rcu);
1113         free_ftrace_hash(hash);
1114 }
1115
1116 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1117 {
1118         if (!hash || hash == EMPTY_HASH)
1119                 return;
1120         call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1121 }
1122
1123 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1124 {
1125         struct ftrace_hash *hash;
1126         int size;
1127
1128         hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1129         if (!hash)
1130                 return NULL;
1131
1132         size = 1 << size_bits;
1133         hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1134
1135         if (!hash->buckets) {
1136                 kfree(hash);
1137                 return NULL;
1138         }
1139
1140         hash->size_bits = size_bits;
1141
1142         return hash;
1143 }
1144
1145 static struct ftrace_hash *
1146 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1147 {
1148         struct ftrace_func_entry *entry;
1149         struct ftrace_hash *new_hash;
1150         struct hlist_node *tp;
1151         int size;
1152         int ret;
1153         int i;
1154
1155         new_hash = alloc_ftrace_hash(size_bits);
1156         if (!new_hash)
1157                 return NULL;
1158
1159         /* Empty hash? */
1160         if (!hash || !hash->count)
1161                 return new_hash;
1162
1163         size = 1 << hash->size_bits;
1164         for (i = 0; i < size; i++) {
1165                 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1166                         ret = add_hash_entry(new_hash, entry->ip);
1167                         if (ret < 0)
1168                                 goto free_hash;
1169                 }
1170         }
1171
1172         FTRACE_WARN_ON(new_hash->count != hash->count);
1173
1174         return new_hash;
1175
1176  free_hash:
1177         free_ftrace_hash(new_hash);
1178         return NULL;
1179 }
1180
1181 static void
1182 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1183 static void
1184 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1185
1186 static int
1187 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1188                  struct ftrace_hash **dst, struct ftrace_hash *src)
1189 {
1190         struct ftrace_func_entry *entry;
1191         struct hlist_node *tp, *tn;
1192         struct hlist_head *hhd;
1193         struct ftrace_hash *old_hash;
1194         struct ftrace_hash *new_hash;
1195         unsigned long key;
1196         int size = src->count;
1197         int bits = 0;
1198         int ret;
1199         int i;
1200
1201         /*
1202          * Remove the current set, update the hash and add
1203          * them back.
1204          */
1205         ftrace_hash_rec_disable(ops, enable);
1206
1207         /*
1208          * If the new source is empty, just free dst and assign it
1209          * the empty_hash.
1210          */
1211         if (!src->count) {
1212                 free_ftrace_hash_rcu(*dst);
1213                 rcu_assign_pointer(*dst, EMPTY_HASH);
1214                 return 0;
1215         }
1216
1217         /*
1218          * Make the hash size about 1/2 the # found
1219          */
1220         for (size /= 2; size; size >>= 1)
1221                 bits++;
1222
1223         /* Don't allocate too much */
1224         if (bits > FTRACE_HASH_MAX_BITS)
1225                 bits = FTRACE_HASH_MAX_BITS;
1226
1227         ret = -ENOMEM;
1228         new_hash = alloc_ftrace_hash(bits);
1229         if (!new_hash)
1230                 goto out;
1231
1232         size = 1 << src->size_bits;
1233         for (i = 0; i < size; i++) {
1234                 hhd = &src->buckets[i];
1235                 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1236                         if (bits > 0)
1237                                 key = hash_long(entry->ip, bits);
1238                         else
1239                                 key = 0;
1240                         remove_hash_entry(src, entry);
1241                         __add_hash_entry(new_hash, entry);
1242                 }
1243         }
1244
1245         old_hash = *dst;
1246         rcu_assign_pointer(*dst, new_hash);
1247         free_ftrace_hash_rcu(old_hash);
1248
1249         ret = 0;
1250  out:
1251         /*
1252          * Enable regardless of ret:
1253          *  On success, we enable the new hash.
1254          *  On failure, we re-enable the original hash.
1255          */
1256         ftrace_hash_rec_enable(ops, enable);
1257
1258         return ret;
1259 }
1260
1261 /*
1262  * Test the hashes for this ops to see if we want to call
1263  * the ops->func or not.
1264  *
1265  * It's a match if the ip is in the ops->filter_hash or
1266  * the filter_hash does not exist or is empty,
1267  *  AND
1268  * the ip is not in the ops->notrace_hash.
1269  *
1270  * This needs to be called with preemption disabled as
1271  * the hashes are freed with call_rcu_sched().
1272  */
1273 static int
1274 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1275 {
1276         struct ftrace_hash *filter_hash;
1277         struct ftrace_hash *notrace_hash;
1278         int ret;
1279
1280         filter_hash = rcu_dereference_raw(ops->filter_hash);
1281         notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1282
1283         if ((!filter_hash || !filter_hash->count ||
1284              ftrace_lookup_ip(filter_hash, ip)) &&
1285             (!notrace_hash || !notrace_hash->count ||
1286              !ftrace_lookup_ip(notrace_hash, ip)))
1287                 ret = 1;
1288         else
1289                 ret = 0;
1290
1291         return ret;
1292 }
1293
1294 /*
1295  * This is a double for. Do not use 'break' to break out of the loop,
1296  * you must use a goto.
1297  */
1298 #define do_for_each_ftrace_rec(pg, rec)                                 \
1299         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1300                 int _____i;                                             \
1301                 for (_____i = 0; _____i < pg->index; _____i++) {        \
1302                         rec = &pg->records[_____i];
1303
1304 #define while_for_each_ftrace_rec()             \
1305                 }                               \
1306         }
1307
1308 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1309                                      int filter_hash,
1310                                      bool inc)
1311 {
1312         struct ftrace_hash *hash;
1313         struct ftrace_hash *other_hash;
1314         struct ftrace_page *pg;
1315         struct dyn_ftrace *rec;
1316         int count = 0;
1317         int all = 0;
1318
1319         /* Only update if the ops has been registered */
1320         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1321                 return;
1322
1323         /*
1324          * In the filter_hash case:
1325          *   If the count is zero, we update all records.
1326          *   Otherwise we just update the items in the hash.
1327          *
1328          * In the notrace_hash case:
1329          *   We enable the update in the hash.
1330          *   As disabling notrace means enabling the tracing,
1331          *   and enabling notrace means disabling, the inc variable
1332          *   gets inversed.
1333          */
1334         if (filter_hash) {
1335                 hash = ops->filter_hash;
1336                 other_hash = ops->notrace_hash;
1337                 if (!hash || !hash->count)
1338                         all = 1;
1339         } else {
1340                 inc = !inc;
1341                 hash = ops->notrace_hash;
1342                 other_hash = ops->filter_hash;
1343                 /*
1344                  * If the notrace hash has no items,
1345                  * then there's nothing to do.
1346                  */
1347                 if (hash && !hash->count)
1348                         return;
1349         }
1350
1351         do_for_each_ftrace_rec(pg, rec) {
1352                 int in_other_hash = 0;
1353                 int in_hash = 0;
1354                 int match = 0;
1355
1356                 if (all) {
1357                         /*
1358                          * Only the filter_hash affects all records.
1359                          * Update if the record is not in the notrace hash.
1360                          */
1361                         if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1362                                 match = 1;
1363                 } else {
1364                         in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1365                         in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1366
1367                         /*
1368                          *
1369                          */
1370                         if (filter_hash && in_hash && !in_other_hash)
1371                                 match = 1;
1372                         else if (!filter_hash && in_hash &&
1373                                  (in_other_hash || !other_hash->count))
1374                                 match = 1;
1375                 }
1376                 if (!match)
1377                         continue;
1378
1379                 if (inc) {
1380                         rec->flags++;
1381                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1382                                 return;
1383                 } else {
1384                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1385                                 return;
1386                         rec->flags--;
1387                 }
1388                 count++;
1389                 /* Shortcut, if we handled all records, we are done. */
1390                 if (!all && count == hash->count)
1391                         return;
1392         } while_for_each_ftrace_rec();
1393 }
1394
1395 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1396                                     int filter_hash)
1397 {
1398         __ftrace_hash_rec_update(ops, filter_hash, 0);
1399 }
1400
1401 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1402                                    int filter_hash)
1403 {
1404         __ftrace_hash_rec_update(ops, filter_hash, 1);
1405 }
1406
1407 static void ftrace_free_rec(struct dyn_ftrace *rec)
1408 {
1409         rec->freelist = ftrace_free_records;
1410         ftrace_free_records = rec;
1411         rec->flags |= FTRACE_FL_FREE;
1412 }
1413
1414 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1415 {
1416         struct dyn_ftrace *rec;
1417
1418         /* First check for freed records */
1419         if (ftrace_free_records) {
1420                 rec = ftrace_free_records;
1421
1422                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
1423                         FTRACE_WARN_ON_ONCE(1);
1424                         ftrace_free_records = NULL;
1425                         return NULL;
1426                 }
1427
1428                 ftrace_free_records = rec->freelist;
1429                 memset(rec, 0, sizeof(*rec));
1430                 return rec;
1431         }
1432
1433         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
1434                 if (!ftrace_pages->next) {
1435                         /* allocate another page */
1436                         ftrace_pages->next =
1437                                 (void *)get_zeroed_page(GFP_KERNEL);
1438                         if (!ftrace_pages->next)
1439                                 return NULL;
1440                 }
1441                 ftrace_pages = ftrace_pages->next;
1442         }
1443
1444         return &ftrace_pages->records[ftrace_pages->index++];
1445 }
1446
1447 static struct dyn_ftrace *
1448 ftrace_record_ip(unsigned long ip)
1449 {
1450         struct dyn_ftrace *rec;
1451
1452         if (ftrace_disabled)
1453                 return NULL;
1454
1455         rec = ftrace_alloc_dyn_node(ip);
1456         if (!rec)
1457                 return NULL;
1458
1459         rec->ip = ip;
1460         rec->newlist = ftrace_new_addrs;
1461         ftrace_new_addrs = rec;
1462
1463         return rec;
1464 }
1465
1466 static void print_ip_ins(const char *fmt, unsigned char *p)
1467 {
1468         int i;
1469
1470         printk(KERN_CONT "%s", fmt);
1471
1472         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1473                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1474 }
1475
1476 static void ftrace_bug(int failed, unsigned long ip)
1477 {
1478         switch (failed) {
1479         case -EFAULT:
1480                 FTRACE_WARN_ON_ONCE(1);
1481                 pr_info("ftrace faulted on modifying ");
1482                 print_ip_sym(ip);
1483                 break;
1484         case -EINVAL:
1485                 FTRACE_WARN_ON_ONCE(1);
1486                 pr_info("ftrace failed to modify ");
1487                 print_ip_sym(ip);
1488                 print_ip_ins(" actual: ", (unsigned char *)ip);
1489                 printk(KERN_CONT "\n");
1490                 break;
1491         case -EPERM:
1492                 FTRACE_WARN_ON_ONCE(1);
1493                 pr_info("ftrace faulted on writing ");
1494                 print_ip_sym(ip);
1495                 break;
1496         default:
1497                 FTRACE_WARN_ON_ONCE(1);
1498                 pr_info("ftrace faulted on unknown error ");
1499                 print_ip_sym(ip);
1500         }
1501 }
1502
1503
1504 /* Return 1 if the address range is reserved for ftrace */
1505 int ftrace_text_reserved(void *start, void *end)
1506 {
1507         struct dyn_ftrace *rec;
1508         struct ftrace_page *pg;
1509
1510         do_for_each_ftrace_rec(pg, rec) {
1511                 if (rec->ip <= (unsigned long)end &&
1512                     rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1513                         return 1;
1514         } while_for_each_ftrace_rec();
1515         return 0;
1516 }
1517
1518
1519 static int
1520 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1521 {
1522         unsigned long ftrace_addr;
1523         unsigned long flag = 0UL;
1524
1525         ftrace_addr = (unsigned long)FTRACE_ADDR;
1526
1527         /*
1528          * If we are enabling tracing:
1529          *
1530          *   If the record has a ref count, then we need to enable it
1531          *   because someone is using it.
1532          *
1533          *   Otherwise we make sure its disabled.
1534          *
1535          * If we are disabling tracing, then disable all records that
1536          * are enabled.
1537          */
1538         if (enable && (rec->flags & ~FTRACE_FL_MASK))
1539                 flag = FTRACE_FL_ENABLED;
1540
1541         /* If the state of this record hasn't changed, then do nothing */
1542         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1543                 return 0;
1544
1545         if (flag) {
1546                 rec->flags |= FTRACE_FL_ENABLED;
1547                 return ftrace_make_call(rec, ftrace_addr);
1548         }
1549
1550         rec->flags &= ~FTRACE_FL_ENABLED;
1551         return ftrace_make_nop(NULL, rec, ftrace_addr);
1552 }
1553
1554 static void ftrace_replace_code(int enable)
1555 {
1556         struct dyn_ftrace *rec;
1557         struct ftrace_page *pg;
1558         int failed;
1559
1560         if (unlikely(ftrace_disabled))
1561                 return;
1562
1563         do_for_each_ftrace_rec(pg, rec) {
1564                 /* Skip over free records */
1565                 if (rec->flags & FTRACE_FL_FREE)
1566                         continue;
1567
1568                 failed = __ftrace_replace_code(rec, enable);
1569                 if (failed) {
1570                         ftrace_bug(failed, rec->ip);
1571                         /* Stop processing */
1572                         return;
1573                 }
1574         } while_for_each_ftrace_rec();
1575 }
1576
1577 static int
1578 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1579 {
1580         unsigned long ip;
1581         int ret;
1582
1583         ip = rec->ip;
1584
1585         if (unlikely(ftrace_disabled))
1586                 return 0;
1587
1588         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1589         if (ret) {
1590                 ftrace_bug(ret, ip);
1591                 return 0;
1592         }
1593         return 1;
1594 }
1595
1596 /*
1597  * archs can override this function if they must do something
1598  * before the modifying code is performed.
1599  */
1600 int __weak ftrace_arch_code_modify_prepare(void)
1601 {
1602         return 0;
1603 }
1604
1605 /*
1606  * archs can override this function if they must do something
1607  * after the modifying code is performed.
1608  */
1609 int __weak ftrace_arch_code_modify_post_process(void)
1610 {
1611         return 0;
1612 }
1613
1614 static int __ftrace_modify_code(void *data)
1615 {
1616         int *command = data;
1617
1618         /*
1619          * Do not call function tracer while we update the code.
1620          * We are in stop machine, no worrying about races.
1621          */
1622         function_trace_stop++;
1623
1624         if (*command & FTRACE_ENABLE_CALLS)
1625                 ftrace_replace_code(1);
1626         else if (*command & FTRACE_DISABLE_CALLS)
1627                 ftrace_replace_code(0);
1628
1629         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1630                 ftrace_update_ftrace_func(ftrace_trace_function);
1631
1632         if (*command & FTRACE_START_FUNC_RET)
1633                 ftrace_enable_ftrace_graph_caller();
1634         else if (*command & FTRACE_STOP_FUNC_RET)
1635                 ftrace_disable_ftrace_graph_caller();
1636
1637 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1638         /*
1639          * For archs that call ftrace_test_stop_func(), we must
1640          * wait till after we update all the function callers
1641          * before we update the callback. This keeps different
1642          * ops that record different functions from corrupting
1643          * each other.
1644          */
1645         __ftrace_trace_function = __ftrace_trace_function_delay;
1646 #endif
1647         function_trace_stop--;
1648
1649         return 0;
1650 }
1651
1652 static void ftrace_run_update_code(int command)
1653 {
1654         int ret;
1655
1656         ret = ftrace_arch_code_modify_prepare();
1657         FTRACE_WARN_ON(ret);
1658         if (ret)
1659                 return;
1660
1661         stop_machine(__ftrace_modify_code, &command, NULL);
1662
1663         ret = ftrace_arch_code_modify_post_process();
1664         FTRACE_WARN_ON(ret);
1665 }
1666
1667 static ftrace_func_t saved_ftrace_func;
1668 static int ftrace_start_up;
1669 static int global_start_up;
1670
1671 static void ftrace_startup_enable(int command)
1672 {
1673         if (saved_ftrace_func != ftrace_trace_function) {
1674                 saved_ftrace_func = ftrace_trace_function;
1675                 command |= FTRACE_UPDATE_TRACE_FUNC;
1676         }
1677
1678         if (!command || !ftrace_enabled)
1679                 return;
1680
1681         ftrace_run_update_code(command);
1682 }
1683
1684 static int ftrace_startup(struct ftrace_ops *ops, int command)
1685 {
1686         bool hash_enable = true;
1687
1688         if (unlikely(ftrace_disabled))
1689                 return -ENODEV;
1690
1691         ftrace_start_up++;
1692         command |= FTRACE_ENABLE_CALLS;
1693
1694         /* ops marked global share the filter hashes */
1695         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1696                 ops = &global_ops;
1697                 /* Don't update hash if global is already set */
1698                 if (global_start_up)
1699                         hash_enable = false;
1700                 global_start_up++;
1701         }
1702
1703         ops->flags |= FTRACE_OPS_FL_ENABLED;
1704         if (hash_enable)
1705                 ftrace_hash_rec_enable(ops, 1);
1706
1707         ftrace_startup_enable(command);
1708
1709         return 0;
1710 }
1711
1712 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1713 {
1714         bool hash_disable = true;
1715
1716         if (unlikely(ftrace_disabled))
1717                 return;
1718
1719         ftrace_start_up--;
1720         /*
1721          * Just warn in case of unbalance, no need to kill ftrace, it's not
1722          * critical but the ftrace_call callers may be never nopped again after
1723          * further ftrace uses.
1724          */
1725         WARN_ON_ONCE(ftrace_start_up < 0);
1726
1727         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1728                 ops = &global_ops;
1729                 global_start_up--;
1730                 WARN_ON_ONCE(global_start_up < 0);
1731                 /* Don't update hash if global still has users */
1732                 if (global_start_up) {
1733                         WARN_ON_ONCE(!ftrace_start_up);
1734                         hash_disable = false;
1735                 }
1736         }
1737
1738         if (hash_disable)
1739                 ftrace_hash_rec_disable(ops, 1);
1740
1741         if (ops != &global_ops || !global_start_up)
1742                 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1743
1744         if (!ftrace_start_up)
1745                 command |= FTRACE_DISABLE_CALLS;
1746
1747         if (saved_ftrace_func != ftrace_trace_function) {
1748                 saved_ftrace_func = ftrace_trace_function;
1749                 command |= FTRACE_UPDATE_TRACE_FUNC;
1750         }
1751
1752         if (!command || !ftrace_enabled)
1753                 return;
1754
1755         ftrace_run_update_code(command);
1756 }
1757
1758 static void ftrace_startup_sysctl(void)
1759 {
1760         if (unlikely(ftrace_disabled))
1761                 return;
1762
1763         /* Force update next time */
1764         saved_ftrace_func = NULL;
1765         /* ftrace_start_up is true if we want ftrace running */
1766         if (ftrace_start_up)
1767                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1768 }
1769
1770 static void ftrace_shutdown_sysctl(void)
1771 {
1772         if (unlikely(ftrace_disabled))
1773                 return;
1774
1775         /* ftrace_start_up is true if ftrace is running */
1776         if (ftrace_start_up)
1777                 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1778 }
1779
1780 static cycle_t          ftrace_update_time;
1781 static unsigned long    ftrace_update_cnt;
1782 unsigned long           ftrace_update_tot_cnt;
1783
1784 static int ops_traces_mod(struct ftrace_ops *ops)
1785 {
1786         struct ftrace_hash *hash;
1787
1788         hash = ops->filter_hash;
1789         return !!(!hash || !hash->count);
1790 }
1791
1792 static int ftrace_update_code(struct module *mod)
1793 {
1794         struct dyn_ftrace *p;
1795         cycle_t start, stop;
1796         unsigned long ref = 0;
1797
1798         /*
1799          * When adding a module, we need to check if tracers are
1800          * currently enabled and if they are set to trace all functions.
1801          * If they are, we need to enable the module functions as well
1802          * as update the reference counts for those function records.
1803          */
1804         if (mod) {
1805                 struct ftrace_ops *ops;
1806
1807                 for (ops = ftrace_ops_list;
1808                      ops != &ftrace_list_end; ops = ops->next) {
1809                         if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1810                             ops_traces_mod(ops))
1811                                 ref++;
1812                 }
1813         }
1814
1815         start = ftrace_now(raw_smp_processor_id());
1816         ftrace_update_cnt = 0;
1817
1818         while (ftrace_new_addrs) {
1819
1820                 /* If something went wrong, bail without enabling anything */
1821                 if (unlikely(ftrace_disabled))
1822                         return -1;
1823
1824                 p = ftrace_new_addrs;
1825                 ftrace_new_addrs = p->newlist;
1826                 p->flags = ref;
1827
1828                 /*
1829                  * Do the initial record conversion from mcount jump
1830                  * to the NOP instructions.
1831                  */
1832                 if (!ftrace_code_disable(mod, p)) {
1833                         ftrace_free_rec(p);
1834                         /* Game over */
1835                         break;
1836                 }
1837
1838                 ftrace_update_cnt++;
1839
1840                 /*
1841                  * If the tracing is enabled, go ahead and enable the record.
1842                  *
1843                  * The reason not to enable the record immediatelly is the
1844                  * inherent check of ftrace_make_nop/ftrace_make_call for
1845                  * correct previous instructions.  Making first the NOP
1846                  * conversion puts the module to the correct state, thus
1847                  * passing the ftrace_make_call check.
1848                  */
1849                 if (ftrace_start_up && ref) {
1850                         int failed = __ftrace_replace_code(p, 1);
1851                         if (failed) {
1852                                 ftrace_bug(failed, p->ip);
1853                                 ftrace_free_rec(p);
1854                         }
1855                 }
1856         }
1857
1858         stop = ftrace_now(raw_smp_processor_id());
1859         ftrace_update_time = stop - start;
1860         ftrace_update_tot_cnt += ftrace_update_cnt;
1861
1862         return 0;
1863 }
1864
1865 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1866 {
1867         struct ftrace_page *pg;
1868         int cnt;
1869         int i;
1870
1871         /* allocate a few pages */
1872         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1873         if (!ftrace_pages_start)
1874                 return -1;
1875
1876         /*
1877          * Allocate a few more pages.
1878          *
1879          * TODO: have some parser search vmlinux before
1880          *   final linking to find all calls to ftrace.
1881          *   Then we can:
1882          *    a) know how many pages to allocate.
1883          *     and/or
1884          *    b) set up the table then.
1885          *
1886          *  The dynamic code is still necessary for
1887          *  modules.
1888          */
1889
1890         pg = ftrace_pages = ftrace_pages_start;
1891
1892         cnt = num_to_init / ENTRIES_PER_PAGE;
1893         pr_info("ftrace: allocating %ld entries in %d pages\n",
1894                 num_to_init, cnt + 1);
1895
1896         for (i = 0; i < cnt; i++) {
1897                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1898
1899                 /* If we fail, we'll try later anyway */
1900                 if (!pg->next)
1901                         break;
1902
1903                 pg = pg->next;
1904         }
1905
1906         return 0;
1907 }
1908
1909 enum {
1910         FTRACE_ITER_FILTER      = (1 << 0),
1911         FTRACE_ITER_NOTRACE     = (1 << 1),
1912         FTRACE_ITER_PRINTALL    = (1 << 2),
1913         FTRACE_ITER_HASH        = (1 << 3),
1914         FTRACE_ITER_ENABLED     = (1 << 4),
1915 };
1916
1917 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1918
1919 struct ftrace_iterator {
1920         loff_t                          pos;
1921         loff_t                          func_pos;
1922         struct ftrace_page              *pg;
1923         struct dyn_ftrace               *func;
1924         struct ftrace_func_probe        *probe;
1925         struct trace_parser             parser;
1926         struct ftrace_hash              *hash;
1927         struct ftrace_ops               *ops;
1928         int                             hidx;
1929         int                             idx;
1930         unsigned                        flags;
1931 };
1932
1933 static void *
1934 t_hash_next(struct seq_file *m, loff_t *pos)
1935 {
1936         struct ftrace_iterator *iter = m->private;
1937         struct hlist_node *hnd = NULL;
1938         struct hlist_head *hhd;
1939
1940         (*pos)++;
1941         iter->pos = *pos;
1942
1943         if (iter->probe)
1944                 hnd = &iter->probe->node;
1945  retry:
1946         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1947                 return NULL;
1948
1949         hhd = &ftrace_func_hash[iter->hidx];
1950
1951         if (hlist_empty(hhd)) {
1952                 iter->hidx++;
1953                 hnd = NULL;
1954                 goto retry;
1955         }
1956
1957         if (!hnd)
1958                 hnd = hhd->first;
1959         else {
1960                 hnd = hnd->next;
1961                 if (!hnd) {
1962                         iter->hidx++;
1963                         goto retry;
1964                 }
1965         }
1966
1967         if (WARN_ON_ONCE(!hnd))
1968                 return NULL;
1969
1970         iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1971
1972         return iter;
1973 }
1974
1975 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1976 {
1977         struct ftrace_iterator *iter = m->private;
1978         void *p = NULL;
1979         loff_t l;
1980
1981         if (iter->func_pos > *pos)
1982                 return NULL;
1983
1984         iter->hidx = 0;
1985         for (l = 0; l <= (*pos - iter->func_pos); ) {
1986                 p = t_hash_next(m, &l);
1987                 if (!p)
1988                         break;
1989         }
1990         if (!p)
1991                 return NULL;
1992
1993         /* Only set this if we have an item */
1994         iter->flags |= FTRACE_ITER_HASH;
1995
1996         return iter;
1997 }
1998
1999 static int
2000 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2001 {
2002         struct ftrace_func_probe *rec;
2003
2004         rec = iter->probe;
2005         if (WARN_ON_ONCE(!rec))
2006                 return -EIO;
2007
2008         if (rec->ops->print)
2009                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2010
2011         seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2012
2013         if (rec->data)
2014                 seq_printf(m, ":%p", rec->data);
2015         seq_putc(m, '\n');
2016
2017         return 0;
2018 }
2019
2020 static void *
2021 t_next(struct seq_file *m, void *v, loff_t *pos)
2022 {
2023         struct ftrace_iterator *iter = m->private;
2024         struct ftrace_ops *ops = &global_ops;
2025         struct dyn_ftrace *rec = NULL;
2026
2027         if (unlikely(ftrace_disabled))
2028                 return NULL;
2029
2030         if (iter->flags & FTRACE_ITER_HASH)
2031                 return t_hash_next(m, pos);
2032
2033         (*pos)++;
2034         iter->pos = iter->func_pos = *pos;
2035
2036         if (iter->flags & FTRACE_ITER_PRINTALL)
2037                 return t_hash_start(m, pos);
2038
2039  retry:
2040         if (iter->idx >= iter->pg->index) {
2041                 if (iter->pg->next) {
2042                         iter->pg = iter->pg->next;
2043                         iter->idx = 0;
2044                         goto retry;
2045                 }
2046         } else {
2047                 rec = &iter->pg->records[iter->idx++];
2048                 if ((rec->flags & FTRACE_FL_FREE) ||
2049
2050                     ((iter->flags & FTRACE_ITER_FILTER) &&
2051                      !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2052
2053                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
2054                      !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2055
2056                     ((iter->flags & FTRACE_ITER_ENABLED) &&
2057                      !(rec->flags & ~FTRACE_FL_MASK))) {
2058
2059                         rec = NULL;
2060                         goto retry;
2061                 }
2062         }
2063
2064         if (!rec)
2065                 return t_hash_start(m, pos);
2066
2067         iter->func = rec;
2068
2069         return iter;
2070 }
2071
2072 static void reset_iter_read(struct ftrace_iterator *iter)
2073 {
2074         iter->pos = 0;
2075         iter->func_pos = 0;
2076         iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2077 }
2078
2079 static void *t_start(struct seq_file *m, loff_t *pos)
2080 {
2081         struct ftrace_iterator *iter = m->private;
2082         struct ftrace_ops *ops = &global_ops;
2083         void *p = NULL;
2084         loff_t l;
2085
2086         mutex_lock(&ftrace_lock);
2087
2088         if (unlikely(ftrace_disabled))
2089                 return NULL;
2090
2091         /*
2092          * If an lseek was done, then reset and start from beginning.
2093          */
2094         if (*pos < iter->pos)
2095                 reset_iter_read(iter);
2096
2097         /*
2098          * For set_ftrace_filter reading, if we have the filter
2099          * off, we can short cut and just print out that all
2100          * functions are enabled.
2101          */
2102         if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
2103                 if (*pos > 0)
2104                         return t_hash_start(m, pos);
2105                 iter->flags |= FTRACE_ITER_PRINTALL;
2106                 /* reset in case of seek/pread */
2107                 iter->flags &= ~FTRACE_ITER_HASH;
2108                 return iter;
2109         }
2110
2111         if (iter->flags & FTRACE_ITER_HASH)
2112                 return t_hash_start(m, pos);
2113
2114         /*
2115          * Unfortunately, we need to restart at ftrace_pages_start
2116          * every time we let go of the ftrace_mutex. This is because
2117          * those pointers can change without the lock.
2118          */
2119         iter->pg = ftrace_pages_start;
2120         iter->idx = 0;
2121         for (l = 0; l <= *pos; ) {
2122                 p = t_next(m, p, &l);
2123                 if (!p)
2124                         break;
2125         }
2126
2127         if (!p) {
2128                 if (iter->flags & FTRACE_ITER_FILTER)
2129                         return t_hash_start(m, pos);
2130
2131                 return NULL;
2132         }
2133
2134         return iter;
2135 }
2136
2137 static void t_stop(struct seq_file *m, void *p)
2138 {
2139         mutex_unlock(&ftrace_lock);
2140 }
2141
2142 static int t_show(struct seq_file *m, void *v)
2143 {
2144         struct ftrace_iterator *iter = m->private;
2145         struct dyn_ftrace *rec;
2146
2147         if (iter->flags & FTRACE_ITER_HASH)
2148                 return t_hash_show(m, iter);
2149
2150         if (iter->flags & FTRACE_ITER_PRINTALL) {
2151                 seq_printf(m, "#### all functions enabled ####\n");
2152                 return 0;
2153         }
2154
2155         rec = iter->func;
2156
2157         if (!rec)
2158                 return 0;
2159
2160         seq_printf(m, "%ps", (void *)rec->ip);
2161         if (iter->flags & FTRACE_ITER_ENABLED)
2162                 seq_printf(m, " (%ld)",
2163                            rec->flags & ~FTRACE_FL_MASK);
2164         seq_printf(m, "\n");
2165
2166         return 0;
2167 }
2168
2169 static const struct seq_operations show_ftrace_seq_ops = {
2170         .start = t_start,
2171         .next = t_next,
2172         .stop = t_stop,
2173         .show = t_show,
2174 };
2175
2176 static int
2177 ftrace_avail_open(struct inode *inode, struct file *file)
2178 {
2179         struct ftrace_iterator *iter;
2180         int ret;
2181
2182         if (unlikely(ftrace_disabled))
2183                 return -ENODEV;
2184
2185         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2186         if (!iter)
2187                 return -ENOMEM;
2188
2189         iter->pg = ftrace_pages_start;
2190
2191         ret = seq_open(file, &show_ftrace_seq_ops);
2192         if (!ret) {
2193                 struct seq_file *m = file->private_data;
2194
2195                 m->private = iter;
2196         } else {
2197                 kfree(iter);
2198         }
2199
2200         return ret;
2201 }
2202
2203 static int
2204 ftrace_enabled_open(struct inode *inode, struct file *file)
2205 {
2206         struct ftrace_iterator *iter;
2207         int ret;
2208
2209         if (unlikely(ftrace_disabled))
2210                 return -ENODEV;
2211
2212         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2213         if (!iter)
2214                 return -ENOMEM;
2215
2216         iter->pg = ftrace_pages_start;
2217         iter->flags = FTRACE_ITER_ENABLED;
2218
2219         ret = seq_open(file, &show_ftrace_seq_ops);
2220         if (!ret) {
2221                 struct seq_file *m = file->private_data;
2222
2223                 m->private = iter;
2224         } else {
2225                 kfree(iter);
2226         }
2227
2228         return ret;
2229 }
2230
2231 static void ftrace_filter_reset(struct ftrace_hash *hash)
2232 {
2233         mutex_lock(&ftrace_lock);
2234         ftrace_hash_clear(hash);
2235         mutex_unlock(&ftrace_lock);
2236 }
2237
2238 static int
2239 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2240                   struct inode *inode, struct file *file)
2241 {
2242         struct ftrace_iterator *iter;
2243         struct ftrace_hash *hash;
2244         int ret = 0;
2245
2246         if (unlikely(ftrace_disabled))
2247                 return -ENODEV;
2248
2249         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2250         if (!iter)
2251                 return -ENOMEM;
2252
2253         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2254                 kfree(iter);
2255                 return -ENOMEM;
2256         }
2257
2258         if (flag & FTRACE_ITER_NOTRACE)
2259                 hash = ops->notrace_hash;
2260         else
2261                 hash = ops->filter_hash;
2262
2263         iter->ops = ops;
2264         iter->flags = flag;
2265
2266         if (file->f_mode & FMODE_WRITE) {
2267                 mutex_lock(&ftrace_lock);
2268                 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2269                 mutex_unlock(&ftrace_lock);
2270
2271                 if (!iter->hash) {
2272                         trace_parser_put(&iter->parser);
2273                         kfree(iter);
2274                         return -ENOMEM;
2275                 }
2276         }
2277
2278         mutex_lock(&ftrace_regex_lock);
2279
2280         if ((file->f_mode & FMODE_WRITE) &&
2281             (file->f_flags & O_TRUNC))
2282                 ftrace_filter_reset(iter->hash);
2283
2284         if (file->f_mode & FMODE_READ) {
2285                 iter->pg = ftrace_pages_start;
2286
2287                 ret = seq_open(file, &show_ftrace_seq_ops);
2288                 if (!ret) {
2289                         struct seq_file *m = file->private_data;
2290                         m->private = iter;
2291                 } else {
2292                         /* Failed */
2293                         free_ftrace_hash(iter->hash);
2294                         trace_parser_put(&iter->parser);
2295                         kfree(iter);
2296                 }
2297         } else
2298                 file->private_data = iter;
2299         mutex_unlock(&ftrace_regex_lock);
2300
2301         return ret;
2302 }
2303
2304 static int
2305 ftrace_filter_open(struct inode *inode, struct file *file)
2306 {
2307         return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2308                                  inode, file);
2309 }
2310
2311 static int
2312 ftrace_notrace_open(struct inode *inode, struct file *file)
2313 {
2314         return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2315                                  inode, file);
2316 }
2317
2318 static loff_t
2319 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2320 {
2321         loff_t ret;
2322
2323         if (file->f_mode & FMODE_READ)
2324                 ret = seq_lseek(file, offset, origin);
2325         else
2326                 file->f_pos = ret = 1;
2327
2328         return ret;
2329 }
2330
2331 static int ftrace_match(char *str, char *regex, int len, int type)
2332 {
2333         int matched = 0;
2334         int slen;
2335
2336         switch (type) {
2337         case MATCH_FULL:
2338                 if (strcmp(str, regex) == 0)
2339                         matched = 1;
2340                 break;
2341         case MATCH_FRONT_ONLY:
2342                 if (strncmp(str, regex, len) == 0)
2343                         matched = 1;
2344                 break;
2345         case MATCH_MIDDLE_ONLY:
2346                 if (strstr(str, regex))
2347                         matched = 1;
2348                 break;
2349         case MATCH_END_ONLY:
2350                 slen = strlen(str);
2351                 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2352                         matched = 1;
2353                 break;
2354         }
2355
2356         return matched;
2357 }
2358
2359 static int
2360 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2361 {
2362         struct ftrace_func_entry *entry;
2363         int ret = 0;
2364
2365         entry = ftrace_lookup_ip(hash, rec->ip);
2366         if (not) {
2367                 /* Do nothing if it doesn't exist */
2368                 if (!entry)
2369                         return 0;
2370
2371                 free_hash_entry(hash, entry);
2372         } else {
2373                 /* Do nothing if it exists */
2374                 if (entry)
2375                         return 0;
2376
2377                 ret = add_hash_entry(hash, rec->ip);
2378         }
2379         return ret;
2380 }
2381
2382 static int
2383 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2384                     char *regex, int len, int type)
2385 {
2386         char str[KSYM_SYMBOL_LEN];
2387         char *modname;
2388
2389         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2390
2391         if (mod) {
2392                 /* module lookup requires matching the module */
2393                 if (!modname || strcmp(modname, mod))
2394                         return 0;
2395
2396                 /* blank search means to match all funcs in the mod */
2397                 if (!len)
2398                         return 1;
2399         }
2400
2401         return ftrace_match(str, regex, len, type);
2402 }
2403
2404 static int
2405 match_records(struct ftrace_hash *hash, char *buff,
2406               int len, char *mod, int not)
2407 {
2408         unsigned search_len = 0;
2409         struct ftrace_page *pg;
2410         struct dyn_ftrace *rec;
2411         int type = MATCH_FULL;
2412         char *search = buff;
2413         int found = 0;
2414         int ret;
2415
2416         if (len) {
2417                 type = filter_parse_regex(buff, len, &search, &not);
2418                 search_len = strlen(search);
2419         }
2420
2421         mutex_lock(&ftrace_lock);
2422
2423         if (unlikely(ftrace_disabled))
2424                 goto out_unlock;
2425
2426         do_for_each_ftrace_rec(pg, rec) {
2427
2428                 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2429                         ret = enter_record(hash, rec, not);
2430                         if (ret < 0) {
2431                                 found = ret;
2432                                 goto out_unlock;
2433                         }
2434                         found = 1;
2435                 }
2436         } while_for_each_ftrace_rec();
2437  out_unlock:
2438         mutex_unlock(&ftrace_lock);
2439
2440         return found;
2441 }
2442
2443 static int
2444 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2445 {
2446         return match_records(hash, buff, len, NULL, 0);
2447 }
2448
2449 static int
2450 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2451 {
2452         int not = 0;
2453
2454         /* blank or '*' mean the same */
2455         if (strcmp(buff, "*") == 0)
2456                 buff[0] = 0;
2457
2458         /* handle the case of 'dont filter this module' */
2459         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2460                 buff[0] = 0;
2461                 not = 1;
2462         }
2463
2464         return match_records(hash, buff, strlen(buff), mod, not);
2465 }
2466
2467 /*
2468  * We register the module command as a template to show others how
2469  * to register the a command as well.
2470  */
2471
2472 static int
2473 ftrace_mod_callback(struct ftrace_hash *hash,
2474                     char *func, char *cmd, char *param, int enable)
2475 {
2476         char *mod;
2477         int ret = -EINVAL;
2478
2479         /*
2480          * cmd == 'mod' because we only registered this func
2481          * for the 'mod' ftrace_func_command.
2482          * But if you register one func with multiple commands,
2483          * you can tell which command was used by the cmd
2484          * parameter.
2485          */
2486
2487         /* we must have a module name */
2488         if (!param)
2489                 return ret;
2490
2491         mod = strsep(&param, ":");
2492         if (!strlen(mod))
2493                 return ret;
2494
2495         ret = ftrace_match_module_records(hash, func, mod);
2496         if (!ret)
2497                 ret = -EINVAL;
2498         if (ret < 0)
2499                 return ret;
2500
2501         return 0;
2502 }
2503
2504 static struct ftrace_func_command ftrace_mod_cmd = {
2505         .name                   = "mod",
2506         .func                   = ftrace_mod_callback,
2507 };
2508
2509 static int __init ftrace_mod_cmd_init(void)
2510 {
2511         return register_ftrace_command(&ftrace_mod_cmd);
2512 }
2513 device_initcall(ftrace_mod_cmd_init);
2514
2515 static void
2516 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2517 {
2518         struct ftrace_func_probe *entry;
2519         struct hlist_head *hhd;
2520         struct hlist_node *n;
2521         unsigned long key;
2522
2523         key = hash_long(ip, FTRACE_HASH_BITS);
2524
2525         hhd = &ftrace_func_hash[key];
2526
2527         if (hlist_empty(hhd))
2528                 return;
2529
2530         /*
2531          * Disable preemption for these calls to prevent a RCU grace
2532          * period. This syncs the hash iteration and freeing of items
2533          * on the hash. rcu_read_lock is too dangerous here.
2534          */
2535         preempt_disable_notrace();
2536         hlist_for_each_entry_rcu(entry, n, hhd, node) {
2537                 if (entry->ip == ip)
2538                         entry->ops->func(ip, parent_ip, &entry->data);
2539         }
2540         preempt_enable_notrace();
2541 }
2542
2543 static struct ftrace_ops trace_probe_ops __read_mostly =
2544 {
2545         .func           = function_trace_probe_call,
2546 };
2547
2548 static int ftrace_probe_registered;
2549
2550 static void __enable_ftrace_function_probe(void)
2551 {
2552         int ret;
2553         int i;
2554
2555         if (ftrace_probe_registered)
2556                 return;
2557
2558         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2559                 struct hlist_head *hhd = &ftrace_func_hash[i];
2560                 if (hhd->first)
2561                         break;
2562         }
2563         /* Nothing registered? */
2564         if (i == FTRACE_FUNC_HASHSIZE)
2565                 return;
2566
2567         ret = __register_ftrace_function(&trace_probe_ops);
2568         if (!ret)
2569                 ret = ftrace_startup(&trace_probe_ops, 0);
2570
2571         ftrace_probe_registered = 1;
2572 }
2573
2574 static void __disable_ftrace_function_probe(void)
2575 {
2576         int ret;
2577         int i;
2578
2579         if (!ftrace_probe_registered)
2580                 return;
2581
2582         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2583                 struct hlist_head *hhd = &ftrace_func_hash[i];
2584                 if (hhd->first)
2585                         return;
2586         }
2587
2588         /* no more funcs left */
2589         ret = __unregister_ftrace_function(&trace_probe_ops);
2590         if (!ret)
2591                 ftrace_shutdown(&trace_probe_ops, 0);
2592
2593         ftrace_probe_registered = 0;
2594 }
2595
2596
2597 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2598 {
2599         struct ftrace_func_probe *entry =
2600                 container_of(rhp, struct ftrace_func_probe, rcu);
2601
2602         if (entry->ops->free)
2603                 entry->ops->free(&entry->data);
2604         kfree(entry);
2605 }
2606
2607
2608 int
2609 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2610                               void *data)
2611 {
2612         struct ftrace_func_probe *entry;
2613         struct ftrace_page *pg;
2614         struct dyn_ftrace *rec;
2615         int type, len, not;
2616         unsigned long key;
2617         int count = 0;
2618         char *search;
2619
2620         type = filter_parse_regex(glob, strlen(glob), &search, &not);
2621         len = strlen(search);
2622
2623         /* we do not support '!' for function probes */
2624         if (WARN_ON(not))
2625                 return -EINVAL;
2626
2627         mutex_lock(&ftrace_lock);
2628
2629         if (unlikely(ftrace_disabled))
2630                 goto out_unlock;
2631
2632         do_for_each_ftrace_rec(pg, rec) {
2633
2634                 if (!ftrace_match_record(rec, NULL, search, len, type))
2635                         continue;
2636
2637                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2638                 if (!entry) {
2639                         /* If we did not process any, then return error */
2640                         if (!count)
2641                                 count = -ENOMEM;
2642                         goto out_unlock;
2643                 }
2644
2645                 count++;
2646
2647                 entry->data = data;
2648
2649                 /*
2650                  * The caller might want to do something special
2651                  * for each function we find. We call the callback
2652                  * to give the caller an opportunity to do so.
2653                  */
2654                 if (ops->callback) {
2655                         if (ops->callback(rec->ip, &entry->data) < 0) {
2656                                 /* caller does not like this func */
2657                                 kfree(entry);
2658                                 continue;
2659                         }
2660                 }
2661
2662                 entry->ops = ops;
2663                 entry->ip = rec->ip;
2664
2665                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2666                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2667
2668         } while_for_each_ftrace_rec();
2669         __enable_ftrace_function_probe();
2670
2671  out_unlock:
2672         mutex_unlock(&ftrace_lock);
2673
2674         return count;
2675 }
2676
2677 enum {
2678         PROBE_TEST_FUNC         = 1,
2679         PROBE_TEST_DATA         = 2
2680 };
2681
2682 static void
2683 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2684                                   void *data, int flags)
2685 {
2686         struct ftrace_func_probe *entry;
2687         struct hlist_node *n, *tmp;
2688         char str[KSYM_SYMBOL_LEN];
2689         int type = MATCH_FULL;
2690         int i, len = 0;
2691         char *search;
2692
2693         if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2694                 glob = NULL;
2695         else if (glob) {
2696                 int not;
2697
2698                 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2699                 len = strlen(search);
2700
2701                 /* we do not support '!' for function probes */
2702                 if (WARN_ON(not))
2703                         return;
2704         }
2705
2706         mutex_lock(&ftrace_lock);
2707         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2708                 struct hlist_head *hhd = &ftrace_func_hash[i];
2709
2710                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2711
2712                         /* break up if statements for readability */
2713                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2714                                 continue;
2715
2716                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2717                                 continue;
2718
2719                         /* do this last, since it is the most expensive */
2720                         if (glob) {
2721                                 kallsyms_lookup(entry->ip, NULL, NULL,
2722                                                 NULL, str);
2723                                 if (!ftrace_match(str, glob, len, type))
2724                                         continue;
2725                         }
2726
2727                         hlist_del(&entry->node);
2728                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2729                 }
2730         }
2731         __disable_ftrace_function_probe();
2732         mutex_unlock(&ftrace_lock);
2733 }
2734
2735 void
2736 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2737                                 void *data)
2738 {
2739         __unregister_ftrace_function_probe(glob, ops, data,
2740                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2741 }
2742
2743 void
2744 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2745 {
2746         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2747 }
2748
2749 void unregister_ftrace_function_probe_all(char *glob)
2750 {
2751         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2752 }
2753
2754 static LIST_HEAD(ftrace_commands);
2755 static DEFINE_MUTEX(ftrace_cmd_mutex);
2756
2757 int register_ftrace_command(struct ftrace_func_command *cmd)
2758 {
2759         struct ftrace_func_command *p;
2760         int ret = 0;
2761
2762         mutex_lock(&ftrace_cmd_mutex);
2763         list_for_each_entry(p, &ftrace_commands, list) {
2764                 if (strcmp(cmd->name, p->name) == 0) {
2765                         ret = -EBUSY;
2766                         goto out_unlock;
2767                 }
2768         }
2769         list_add(&cmd->list, &ftrace_commands);
2770  out_unlock:
2771         mutex_unlock(&ftrace_cmd_mutex);
2772
2773         return ret;
2774 }
2775
2776 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2777 {
2778         struct ftrace_func_command *p, *n;
2779         int ret = -ENODEV;
2780
2781         mutex_lock(&ftrace_cmd_mutex);
2782         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2783                 if (strcmp(cmd->name, p->name) == 0) {
2784                         ret = 0;
2785                         list_del_init(&p->list);
2786                         goto out_unlock;
2787                 }
2788         }
2789  out_unlock:
2790         mutex_unlock(&ftrace_cmd_mutex);
2791
2792         return ret;
2793 }
2794
2795 static int ftrace_process_regex(struct ftrace_hash *hash,
2796                                 char *buff, int len, int enable)
2797 {
2798         char *func, *command, *next = buff;
2799         struct ftrace_func_command *p;
2800         int ret = -EINVAL;
2801
2802         func = strsep(&next, ":");
2803
2804         if (!next) {
2805                 ret = ftrace_match_records(hash, func, len);
2806                 if (!ret)
2807                         ret = -EINVAL;
2808                 if (ret < 0)
2809                         return ret;
2810                 return 0;
2811         }
2812
2813         /* command found */
2814
2815         command = strsep(&next, ":");
2816
2817         mutex_lock(&ftrace_cmd_mutex);
2818         list_for_each_entry(p, &ftrace_commands, list) {
2819                 if (strcmp(p->name, command) == 0) {
2820                         ret = p->func(hash, func, command, next, enable);
2821                         goto out_unlock;
2822                 }
2823         }
2824  out_unlock:
2825         mutex_unlock(&ftrace_cmd_mutex);
2826
2827         return ret;
2828 }
2829
2830 static ssize_t
2831 ftrace_regex_write(struct file *file, const char __user *ubuf,
2832                    size_t cnt, loff_t *ppos, int enable)
2833 {
2834         struct ftrace_iterator *iter;
2835         struct trace_parser *parser;
2836         ssize_t ret, read;
2837
2838         if (!cnt)
2839                 return 0;
2840
2841         mutex_lock(&ftrace_regex_lock);
2842
2843         ret = -ENODEV;
2844         if (unlikely(ftrace_disabled))
2845                 goto out_unlock;
2846
2847         if (file->f_mode & FMODE_READ) {
2848                 struct seq_file *m = file->private_data;
2849                 iter = m->private;
2850         } else
2851                 iter = file->private_data;
2852
2853         parser = &iter->parser;
2854         read = trace_get_user(parser, ubuf, cnt, ppos);
2855
2856         if (read >= 0 && trace_parser_loaded(parser) &&
2857             !trace_parser_cont(parser)) {
2858                 ret = ftrace_process_regex(iter->hash, parser->buffer,
2859                                            parser->idx, enable);
2860                 trace_parser_clear(parser);
2861                 if (ret)
2862                         goto out_unlock;
2863         }
2864
2865         ret = read;
2866 out_unlock:
2867         mutex_unlock(&ftrace_regex_lock);
2868
2869         return ret;
2870 }
2871
2872 static ssize_t
2873 ftrace_filter_write(struct file *file, const char __user *ubuf,
2874                     size_t cnt, loff_t *ppos)
2875 {
2876         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2877 }
2878
2879 static ssize_t
2880 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2881                      size_t cnt, loff_t *ppos)
2882 {
2883         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2884 }
2885
2886 static int
2887 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
2888                  int reset, int enable)
2889 {
2890         struct ftrace_hash **orig_hash;
2891         struct ftrace_hash *hash;
2892         int ret;
2893
2894         /* All global ops uses the global ops filters */
2895         if (ops->flags & FTRACE_OPS_FL_GLOBAL)
2896                 ops = &global_ops;
2897
2898         if (unlikely(ftrace_disabled))
2899                 return -ENODEV;
2900
2901         if (enable)
2902                 orig_hash = &ops->filter_hash;
2903         else
2904                 orig_hash = &ops->notrace_hash;
2905
2906         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
2907         if (!hash)
2908                 return -ENOMEM;
2909
2910         mutex_lock(&ftrace_regex_lock);
2911         if (reset)
2912                 ftrace_filter_reset(hash);
2913         if (buf)
2914                 ftrace_match_records(hash, buf, len);
2915
2916         mutex_lock(&ftrace_lock);
2917         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
2918         if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
2919             && ftrace_enabled)
2920                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2921
2922         mutex_unlock(&ftrace_lock);
2923
2924         mutex_unlock(&ftrace_regex_lock);
2925
2926         free_ftrace_hash(hash);
2927         return ret;
2928 }
2929
2930 /**
2931  * ftrace_set_filter - set a function to filter on in ftrace
2932  * @ops - the ops to set the filter with
2933  * @buf - the string that holds the function filter text.
2934  * @len - the length of the string.
2935  * @reset - non zero to reset all filters before applying this filter.
2936  *
2937  * Filters denote which functions should be enabled when tracing is enabled.
2938  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2939  */
2940 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
2941                        int len, int reset)
2942 {
2943         ftrace_set_regex(ops, buf, len, reset, 1);
2944 }
2945 EXPORT_SYMBOL_GPL(ftrace_set_filter);
2946
2947 /**
2948  * ftrace_set_notrace - set a function to not trace in ftrace
2949  * @ops - the ops to set the notrace filter with
2950  * @buf - the string that holds the function notrace text.
2951  * @len - the length of the string.
2952  * @reset - non zero to reset all filters before applying this filter.
2953  *
2954  * Notrace Filters denote which functions should not be enabled when tracing
2955  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2956  * for tracing.
2957  */
2958 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
2959                         int len, int reset)
2960 {
2961         ftrace_set_regex(ops, buf, len, reset, 0);
2962 }
2963 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
2964 /**
2965  * ftrace_set_filter - set a function to filter on in ftrace
2966  * @ops - the ops to set the filter with
2967  * @buf - the string that holds the function filter text.
2968  * @len - the length of the string.
2969  * @reset - non zero to reset all filters before applying this filter.
2970  *
2971  * Filters denote which functions should be enabled when tracing is enabled.
2972  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2973  */
2974 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
2975 {
2976         ftrace_set_regex(&global_ops, buf, len, reset, 1);
2977 }
2978 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
2979
2980 /**
2981  * ftrace_set_notrace - set a function to not trace in ftrace
2982  * @ops - the ops to set the notrace filter with
2983  * @buf - the string that holds the function notrace text.
2984  * @len - the length of the string.
2985  * @reset - non zero to reset all filters before applying this filter.
2986  *
2987  * Notrace Filters denote which functions should not be enabled when tracing
2988  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2989  * for tracing.
2990  */
2991 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
2992 {
2993         ftrace_set_regex(&global_ops, buf, len, reset, 0);
2994 }
2995 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
2996
2997 /*
2998  * command line interface to allow users to set filters on boot up.
2999  */
3000 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
3001 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3002 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3003
3004 static int __init set_ftrace_notrace(char *str)
3005 {
3006         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3007         return 1;
3008 }
3009 __setup("ftrace_notrace=", set_ftrace_notrace);
3010
3011 static int __init set_ftrace_filter(char *str)
3012 {
3013         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3014         return 1;
3015 }
3016 __setup("ftrace_filter=", set_ftrace_filter);
3017
3018 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3019 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3020 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3021
3022 static int __init set_graph_function(char *str)
3023 {
3024         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3025         return 1;
3026 }
3027 __setup("ftrace_graph_filter=", set_graph_function);
3028
3029 static void __init set_ftrace_early_graph(char *buf)
3030 {
3031         int ret;
3032         char *func;
3033
3034         while (buf) {
3035                 func = strsep(&buf, ",");
3036                 /* we allow only one expression at a time */
3037                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3038                                       func);
3039                 if (ret)
3040                         printk(KERN_DEBUG "ftrace: function %s not "
3041                                           "traceable\n", func);
3042         }
3043 }
3044 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3045
3046 static void __init
3047 set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3048 {
3049         char *func;
3050
3051         while (buf) {
3052                 func = strsep(&buf, ",");
3053                 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3054         }
3055 }
3056
3057 static void __init set_ftrace_early_filters(void)
3058 {
3059         if (ftrace_filter_buf[0])
3060                 set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3061         if (ftrace_notrace_buf[0])
3062                 set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3063 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3064         if (ftrace_graph_buf[0])
3065                 set_ftrace_early_graph(ftrace_graph_buf);
3066 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3067 }
3068
3069 static int
3070 ftrace_regex_release(struct inode *inode, struct file *file)
3071 {
3072         struct seq_file *m = (struct seq_file *)file->private_data;
3073         struct ftrace_iterator *iter;
3074         struct ftrace_hash **orig_hash;
3075         struct trace_parser *parser;
3076         int filter_hash;
3077         int ret;
3078
3079         mutex_lock(&ftrace_regex_lock);
3080         if (file->f_mode & FMODE_READ) {
3081                 iter = m->private;
3082
3083                 seq_release(inode, file);
3084         } else
3085                 iter = file->private_data;
3086
3087         parser = &iter->parser;
3088         if (trace_parser_loaded(parser)) {
3089                 parser->buffer[parser->idx] = 0;
3090                 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3091         }
3092
3093         trace_parser_put(parser);
3094
3095         if (file->f_mode & FMODE_WRITE) {
3096                 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3097
3098                 if (filter_hash)
3099                         orig_hash = &iter->ops->filter_hash;
3100                 else
3101                         orig_hash = &iter->ops->notrace_hash;
3102
3103                 mutex_lock(&ftrace_lock);
3104                 ret = ftrace_hash_move(iter->ops, filter_hash,
3105                                        orig_hash, iter->hash);
3106                 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3107                     && ftrace_enabled)
3108                         ftrace_run_update_code(FTRACE_ENABLE_CALLS);
3109
3110                 mutex_unlock(&ftrace_lock);
3111         }
3112         free_ftrace_hash(iter->hash);
3113         kfree(iter);
3114
3115         mutex_unlock(&ftrace_regex_lock);
3116         return 0;
3117 }
3118
3119 static const struct file_operations ftrace_avail_fops = {
3120         .open = ftrace_avail_open,
3121         .read = seq_read,
3122         .llseek = seq_lseek,
3123         .release = seq_release_private,
3124 };
3125
3126 static const struct file_operations ftrace_enabled_fops = {
3127         .open = ftrace_enabled_open,
3128         .read = seq_read,
3129         .llseek = seq_lseek,
3130         .release = seq_release_private,
3131 };
3132
3133 static const struct file_operations ftrace_filter_fops = {
3134         .open = ftrace_filter_open,
3135         .read = seq_read,
3136         .write = ftrace_filter_write,
3137         .llseek = ftrace_regex_lseek,
3138         .release = ftrace_regex_release,
3139 };
3140
3141 static const struct file_operations ftrace_notrace_fops = {
3142         .open = ftrace_notrace_open,
3143         .read = seq_read,
3144         .write = ftrace_notrace_write,
3145         .llseek = ftrace_regex_lseek,
3146         .release = ftrace_regex_release,
3147 };
3148
3149 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3150
3151 static DEFINE_MUTEX(graph_lock);
3152
3153 int ftrace_graph_count;
3154 int ftrace_graph_filter_enabled;
3155 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3156
3157 static void *
3158 __g_next(struct seq_file *m, loff_t *pos)
3159 {
3160         if (*pos >= ftrace_graph_count)
3161                 return NULL;
3162         return &ftrace_graph_funcs[*pos];
3163 }
3164
3165 static void *
3166 g_next(struct seq_file *m, void *v, loff_t *pos)
3167 {
3168         (*pos)++;
3169         return __g_next(m, pos);
3170 }
3171
3172 static void *g_start(struct seq_file *m, loff_t *pos)
3173 {
3174         mutex_lock(&graph_lock);
3175
3176         /* Nothing, tell g_show to print all functions are enabled */
3177         if (!ftrace_graph_filter_enabled && !*pos)
3178                 return (void *)1;
3179
3180         return __g_next(m, pos);
3181 }
3182
3183 static void g_stop(struct seq_file *m, void *p)
3184 {
3185         mutex_unlock(&graph_lock);
3186 }
3187
3188 static int g_show(struct seq_file *m, void *v)
3189 {
3190         unsigned long *ptr = v;
3191
3192         if (!ptr)
3193                 return 0;
3194
3195         if (ptr == (unsigned long *)1) {
3196                 seq_printf(m, "#### all functions enabled ####\n");
3197                 return 0;
3198         }
3199
3200         seq_printf(m, "%ps\n", (void *)*ptr);
3201
3202         return 0;
3203 }
3204
3205 static const struct seq_operations ftrace_graph_seq_ops = {
3206         .start = g_start,
3207         .next = g_next,
3208         .stop = g_stop,
3209         .show = g_show,
3210 };
3211
3212 static int
3213 ftrace_graph_open(struct inode *inode, struct file *file)
3214 {
3215         int ret = 0;
3216
3217         if (unlikely(ftrace_disabled))
3218                 return -ENODEV;
3219
3220         mutex_lock(&graph_lock);
3221         if ((file->f_mode & FMODE_WRITE) &&
3222             (file->f_flags & O_TRUNC)) {
3223                 ftrace_graph_filter_enabled = 0;
3224                 ftrace_graph_count = 0;
3225                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3226         }
3227         mutex_unlock(&graph_lock);
3228
3229         if (file->f_mode & FMODE_READ)
3230                 ret = seq_open(file, &ftrace_graph_seq_ops);
3231
3232         return ret;
3233 }
3234
3235 static int
3236 ftrace_graph_release(struct inode *inode, struct file *file)
3237 {
3238         if (file->f_mode & FMODE_READ)
3239                 seq_release(inode, file);
3240         return 0;
3241 }
3242
3243 static int
3244 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3245 {
3246         struct dyn_ftrace *rec;
3247         struct ftrace_page *pg;
3248         int search_len;
3249         int fail = 1;
3250         int type, not;
3251         char *search;
3252         bool exists;
3253         int i;
3254
3255         /* decode regex */
3256         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3257         if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3258                 return -EBUSY;
3259
3260         search_len = strlen(search);
3261
3262         mutex_lock(&ftrace_lock);
3263
3264         if (unlikely(ftrace_disabled)) {
3265                 mutex_unlock(&ftrace_lock);
3266                 return -ENODEV;
3267         }
3268
3269         do_for_each_ftrace_rec(pg, rec) {
3270
3271                 if (rec->flags & FTRACE_FL_FREE)
3272                         continue;
3273
3274                 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3275                         /* if it is in the array */
3276                         exists = false;
3277                         for (i = 0; i < *idx; i++) {
3278                                 if (array[i] == rec->ip) {
3279                                         exists = true;
3280                                         break;
3281                                 }
3282                         }
3283
3284                         if (!not) {
3285                                 fail = 0;
3286                                 if (!exists) {
3287                                         array[(*idx)++] = rec->ip;
3288                                         if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3289                                                 goto out;
3290                                 }
3291                         } else {
3292                                 if (exists) {
3293                                         array[i] = array[--(*idx)];
3294                                         array[*idx] = 0;
3295                                         fail = 0;
3296                                 }
3297                         }
3298                 }
3299         } while_for_each_ftrace_rec();
3300 out:
3301         mutex_unlock(&ftrace_lock);
3302
3303         if (fail)
3304                 return -EINVAL;
3305
3306         ftrace_graph_filter_enabled = 1;
3307         return 0;
3308 }
3309
3310 static ssize_t
3311 ftrace_graph_write(struct file *file, const char __user *ubuf,
3312                    size_t cnt, loff_t *ppos)
3313 {
3314         struct trace_parser parser;
3315         ssize_t read, ret;
3316
3317         if (!cnt)
3318                 return 0;
3319
3320         mutex_lock(&graph_lock);
3321
3322         if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3323                 ret = -ENOMEM;
3324                 goto out_unlock;
3325         }
3326
3327         read = trace_get_user(&parser, ubuf, cnt, ppos);
3328
3329         if (read >= 0 && trace_parser_loaded((&parser))) {
3330                 parser.buffer[parser.idx] = 0;
3331
3332                 /* we allow only one expression at a time */
3333                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3334                                         parser.buffer);
3335                 if (ret)
3336                         goto out_free;
3337         }
3338
3339         ret = read;
3340
3341 out_free:
3342         trace_parser_put(&parser);
3343 out_unlock:
3344         mutex_unlock(&graph_lock);
3345
3346         return ret;
3347 }
3348
3349 static const struct file_operations ftrace_graph_fops = {
3350         .open           = ftrace_graph_open,
3351         .read           = seq_read,
3352         .write          = ftrace_graph_write,
3353         .release        = ftrace_graph_release,
3354         .llseek         = seq_lseek,
3355 };
3356 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3357
3358 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3359 {
3360
3361         trace_create_file("available_filter_functions", 0444,
3362                         d_tracer, NULL, &ftrace_avail_fops);
3363
3364         trace_create_file("enabled_functions", 0444,
3365                         d_tracer, NULL, &ftrace_enabled_fops);
3366
3367         trace_create_file("set_ftrace_filter", 0644, d_tracer,
3368                         NULL, &ftrace_filter_fops);
3369
3370         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3371                                     NULL, &ftrace_notrace_fops);
3372
3373 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3374         trace_create_file("set_graph_function", 0444, d_tracer,
3375                                     NULL,
3376                                     &ftrace_graph_fops);
3377 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3378
3379         return 0;
3380 }
3381
3382 static int ftrace_process_locs(struct module *mod,
3383                                unsigned long *start,
3384                                unsigned long *end)
3385 {
3386         unsigned long *p;
3387         unsigned long addr;
3388         unsigned long flags = 0; /* Shut up gcc */
3389
3390         mutex_lock(&ftrace_lock);
3391         p = start;
3392         while (p < end) {
3393                 addr = ftrace_call_adjust(*p++);
3394                 /*
3395                  * Some architecture linkers will pad between
3396                  * the different mcount_loc sections of different
3397                  * object files to satisfy alignments.
3398                  * Skip any NULL pointers.
3399                  */
3400                 if (!addr)
3401                         continue;
3402                 ftrace_record_ip(addr);
3403         }
3404
3405         /*
3406          * We only need to disable interrupts on start up
3407          * because we are modifying code that an interrupt
3408          * may execute, and the modification is not atomic.
3409          * But for modules, nothing runs the code we modify
3410          * until we are finished with it, and there's no
3411          * reason to cause large interrupt latencies while we do it.
3412          */
3413         if (!mod)
3414                 local_irq_save(flags);
3415         ftrace_update_code(mod);
3416         if (!mod)
3417                 local_irq_restore(flags);
3418         mutex_unlock(&ftrace_lock);
3419
3420         return 0;
3421 }
3422
3423 #ifdef CONFIG_MODULES
3424 void ftrace_release_mod(struct module *mod)
3425 {
3426         struct dyn_ftrace *rec;
3427         struct ftrace_page *pg;
3428
3429         mutex_lock(&ftrace_lock);
3430
3431         if (ftrace_disabled)
3432                 goto out_unlock;
3433
3434         do_for_each_ftrace_rec(pg, rec) {
3435                 if (within_module_core(rec->ip, mod)) {
3436                         /*
3437                          * rec->ip is changed in ftrace_free_rec()
3438                          * It should not between s and e if record was freed.
3439                          */
3440                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
3441                         ftrace_free_rec(rec);
3442                 }
3443         } while_for_each_ftrace_rec();
3444  out_unlock:
3445         mutex_unlock(&ftrace_lock);
3446 }
3447
3448 static void ftrace_init_module(struct module *mod,
3449                                unsigned long *start, unsigned long *end)
3450 {
3451         if (ftrace_disabled || start == end)
3452                 return;
3453         ftrace_process_locs(mod, start, end);
3454 }
3455
3456 static int ftrace_module_notify(struct notifier_block *self,
3457                                 unsigned long val, void *data)
3458 {
3459         struct module *mod = data;
3460
3461         switch (val) {
3462         case MODULE_STATE_COMING:
3463                 ftrace_init_module(mod, mod->ftrace_callsites,
3464                                    mod->ftrace_callsites +
3465                                    mod->num_ftrace_callsites);
3466                 break;
3467         case MODULE_STATE_GOING:
3468                 ftrace_release_mod(mod);
3469                 break;
3470         }
3471
3472         return 0;
3473 }
3474 #else
3475 static int ftrace_module_notify(struct notifier_block *self,
3476                                 unsigned long val, void *data)
3477 {
3478         return 0;
3479 }
3480 #endif /* CONFIG_MODULES */
3481
3482 struct notifier_block ftrace_module_nb = {
3483         .notifier_call = ftrace_module_notify,
3484         .priority = 0,
3485 };
3486
3487 extern unsigned long __start_mcount_loc[];
3488 extern unsigned long __stop_mcount_loc[];
3489
3490 void __init ftrace_init(void)
3491 {
3492         unsigned long count, addr, flags;
3493         int ret;
3494
3495         /* Keep the ftrace pointer to the stub */
3496         addr = (unsigned long)ftrace_stub;
3497
3498         local_irq_save(flags);
3499         ftrace_dyn_arch_init(&addr);
3500         local_irq_restore(flags);
3501
3502         /* ftrace_dyn_arch_init places the return code in addr */
3503         if (addr)
3504                 goto failed;
3505
3506         count = __stop_mcount_loc - __start_mcount_loc;
3507
3508         ret = ftrace_dyn_table_alloc(count);
3509         if (ret)
3510                 goto failed;
3511
3512         last_ftrace_enabled = ftrace_enabled = 1;
3513
3514         ret = ftrace_process_locs(NULL,
3515                                   __start_mcount_loc,
3516                                   __stop_mcount_loc);
3517
3518         ret = register_module_notifier(&ftrace_module_nb);
3519         if (ret)
3520                 pr_warning("Failed to register trace ftrace module notifier\n");
3521
3522         set_ftrace_early_filters();
3523
3524         return;
3525  failed:
3526         ftrace_disabled = 1;
3527 }
3528
3529 #else
3530
3531 static struct ftrace_ops global_ops = {
3532         .func                   = ftrace_stub,
3533 };
3534
3535 static int __init ftrace_nodyn_init(void)
3536 {
3537         ftrace_enabled = 1;
3538         return 0;
3539 }
3540 device_initcall(ftrace_nodyn_init);
3541
3542 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3543 static inline void ftrace_startup_enable(int command) { }
3544 /* Keep as macros so we do not need to define the commands */
3545 # define ftrace_startup(ops, command)                   \
3546         ({                                              \
3547                 (ops)->flags |= FTRACE_OPS_FL_ENABLED;  \
3548                 0;                                      \
3549         })
3550 # define ftrace_shutdown(ops, command)  do { } while (0)
3551 # define ftrace_startup_sysctl()        do { } while (0)
3552 # define ftrace_shutdown_sysctl()       do { } while (0)
3553
3554 static inline int
3555 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3556 {
3557         return 1;
3558 }
3559
3560 #endif /* CONFIG_DYNAMIC_FTRACE */
3561
3562 static void
3563 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3564 {
3565         struct ftrace_ops *op;
3566
3567         if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3568                 return;
3569
3570         trace_recursion_set(TRACE_INTERNAL_BIT);
3571         /*
3572          * Some of the ops may be dynamically allocated,
3573          * they must be freed after a synchronize_sched().
3574          */
3575         preempt_disable_notrace();
3576         op = rcu_dereference_raw(ftrace_ops_list);
3577         while (op != &ftrace_list_end) {
3578                 if (ftrace_ops_test(op, ip))
3579                         op->func(ip, parent_ip);
3580                 op = rcu_dereference_raw(op->next);
3581         };
3582         preempt_enable_notrace();
3583         trace_recursion_clear(TRACE_INTERNAL_BIT);
3584 }
3585
3586 static void clear_ftrace_swapper(void)
3587 {
3588         struct task_struct *p;
3589         int cpu;
3590
3591         get_online_cpus();
3592         for_each_online_cpu(cpu) {
3593                 p = idle_task(cpu);
3594                 clear_tsk_trace_trace(p);
3595         }
3596         put_online_cpus();
3597 }
3598
3599 static void set_ftrace_swapper(void)
3600 {
3601         struct task_struct *p;
3602         int cpu;
3603
3604         get_online_cpus();
3605         for_each_online_cpu(cpu) {
3606                 p = idle_task(cpu);
3607                 set_tsk_trace_trace(p);
3608         }
3609         put_online_cpus();
3610 }
3611
3612 static void clear_ftrace_pid(struct pid *pid)
3613 {
3614         struct task_struct *p;
3615
3616         rcu_read_lock();
3617         do_each_pid_task(pid, PIDTYPE_PID, p) {
3618                 clear_tsk_trace_trace(p);
3619         } while_each_pid_task(pid, PIDTYPE_PID, p);
3620         rcu_read_unlock();
3621
3622         put_pid(pid);
3623 }
3624
3625 static void set_ftrace_pid(struct pid *pid)
3626 {
3627         struct task_struct *p;
3628
3629         rcu_read_lock();
3630         do_each_pid_task(pid, PIDTYPE_PID, p) {
3631                 set_tsk_trace_trace(p);
3632         } while_each_pid_task(pid, PIDTYPE_PID, p);
3633         rcu_read_unlock();
3634 }
3635
3636 static void clear_ftrace_pid_task(struct pid *pid)
3637 {
3638         if (pid == ftrace_swapper_pid)
3639                 clear_ftrace_swapper();
3640         else
3641                 clear_ftrace_pid(pid);
3642 }
3643
3644 static void set_ftrace_pid_task(struct pid *pid)
3645 {
3646         if (pid == ftrace_swapper_pid)
3647                 set_ftrace_swapper();
3648         else
3649                 set_ftrace_pid(pid);
3650 }
3651
3652 static int ftrace_pid_add(int p)
3653 {
3654         struct pid *pid;
3655         struct ftrace_pid *fpid;
3656         int ret = -EINVAL;
3657
3658         mutex_lock(&ftrace_lock);
3659
3660         if (!p)
3661                 pid = ftrace_swapper_pid;
3662         else
3663                 pid = find_get_pid(p);
3664
3665         if (!pid)
3666                 goto out;
3667
3668         ret = 0;
3669
3670         list_for_each_entry(fpid, &ftrace_pids, list)
3671                 if (fpid->pid == pid)
3672                         goto out_put;
3673
3674         ret = -ENOMEM;
3675
3676         fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3677         if (!fpid)
3678                 goto out_put;
3679
3680         list_add(&fpid->list, &ftrace_pids);
3681         fpid->pid = pid;
3682
3683         set_ftrace_pid_task(pid);
3684
3685         ftrace_update_pid_func();
3686         ftrace_startup_enable(0);
3687
3688         mutex_unlock(&ftrace_lock);
3689         return 0;
3690
3691 out_put:
3692         if (pid != ftrace_swapper_pid)
3693                 put_pid(pid);
3694
3695 out:
3696         mutex_unlock(&ftrace_lock);
3697         return ret;
3698 }
3699
3700 static void ftrace_pid_reset(void)
3701 {
3702         struct ftrace_pid *fpid, *safe;
3703
3704         mutex_lock(&ftrace_lock);
3705         list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3706                 struct pid *pid = fpid->pid;
3707
3708                 clear_ftrace_pid_task(pid);
3709
3710                 list_del(&fpid->list);
3711                 kfree(fpid);
3712         }
3713
3714         ftrace_update_pid_func();
3715         ftrace_startup_enable(0);
3716
3717         mutex_unlock(&ftrace_lock);
3718 }
3719
3720 static void *fpid_start(struct seq_file *m, loff_t *pos)
3721 {
3722         mutex_lock(&ftrace_lock);
3723
3724         if (list_empty(&ftrace_pids) && (!*pos))
3725                 return (void *) 1;
3726
3727         return seq_list_start(&ftrace_pids, *pos);
3728 }
3729
3730 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3731 {
3732         if (v == (void *)1)
3733                 return NULL;
3734
3735         return seq_list_next(v, &ftrace_pids, pos);
3736 }
3737
3738 static void fpid_stop(struct seq_file *m, void *p)
3739 {
3740         mutex_unlock(&ftrace_lock);
3741 }
3742
3743 static int fpid_show(struct seq_file *m, void *v)
3744 {
3745         const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3746
3747         if (v == (void *)1) {
3748                 seq_printf(m, "no pid\n");
3749                 return 0;
3750         }
3751
3752         if (fpid->pid == ftrace_swapper_pid)
3753                 seq_printf(m, "swapper tasks\n");
3754         else
3755                 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3756
3757         return 0;
3758 }
3759
3760 static const struct seq_operations ftrace_pid_sops = {
3761         .start = fpid_start,
3762         .next = fpid_next,
3763         .stop = fpid_stop,
3764         .show = fpid_show,
3765 };
3766
3767 static int
3768 ftrace_pid_open(struct inode *inode, struct file *file)
3769 {
3770         int ret = 0;
3771
3772         if ((file->f_mode & FMODE_WRITE) &&
3773             (file->f_flags & O_TRUNC))
3774                 ftrace_pid_reset();
3775
3776         if (file->f_mode & FMODE_READ)
3777                 ret = seq_open(file, &ftrace_pid_sops);
3778
3779         return ret;
3780 }
3781
3782 static ssize_t
3783 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3784                    size_t cnt, loff_t *ppos)
3785 {
3786         char buf[64], *tmp;
3787         long val;
3788         int ret;
3789
3790         if (cnt >= sizeof(buf))
3791                 return -EINVAL;
3792
3793         if (copy_from_user(&buf, ubuf, cnt))
3794                 return -EFAULT;
3795
3796         buf[cnt] = 0;
3797
3798         /*
3799          * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3800          * to clean the filter quietly.
3801          */
3802         tmp = strstrip(buf);
3803         if (strlen(tmp) == 0)
3804                 return 1;
3805
3806         ret = strict_strtol(tmp, 10, &val);
3807         if (ret < 0)
3808                 return ret;
3809
3810         ret = ftrace_pid_add(val);
3811
3812         return ret ? ret : cnt;
3813 }
3814
3815 static int
3816 ftrace_pid_release(struct inode *inode, struct file *file)
3817 {
3818         if (file->f_mode & FMODE_READ)
3819                 seq_release(inode, file);
3820
3821         return 0;
3822 }
3823
3824 static const struct file_operations ftrace_pid_fops = {
3825         .open           = ftrace_pid_open,
3826         .write          = ftrace_pid_write,
3827         .read           = seq_read,
3828         .llseek         = seq_lseek,
3829         .release        = ftrace_pid_release,
3830 };
3831
3832 static __init int ftrace_init_debugfs(void)
3833 {
3834         struct dentry *d_tracer;
3835
3836         d_tracer = tracing_init_dentry();
3837         if (!d_tracer)
3838                 return 0;
3839
3840         ftrace_init_dyn_debugfs(d_tracer);
3841
3842         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3843                             NULL, &ftrace_pid_fops);
3844
3845         ftrace_profile_debugfs(d_tracer);
3846
3847         return 0;
3848 }
3849 fs_initcall(ftrace_init_debugfs);
3850
3851 /**
3852  * ftrace_kill - kill ftrace
3853  *
3854  * This function should be used by panic code. It stops ftrace
3855  * but in a not so nice way. If you need to simply kill ftrace
3856  * from a non-atomic section, use ftrace_kill.
3857  */
3858 void ftrace_kill(void)
3859 {
3860         ftrace_disabled = 1;
3861         ftrace_enabled = 0;
3862         clear_ftrace_function();
3863 }
3864
3865 /**
3866  * Test if ftrace is dead or not.
3867  */
3868 int ftrace_is_dead(void)
3869 {
3870         return ftrace_disabled;
3871 }
3872
3873 /**
3874  * register_ftrace_function - register a function for profiling
3875  * @ops - ops structure that holds the function for profiling.
3876  *
3877  * Register a function to be called by all functions in the
3878  * kernel.
3879  *
3880  * Note: @ops->func and all the functions it calls must be labeled
3881  *       with "notrace", otherwise it will go into a
3882  *       recursive loop.
3883  */
3884 int register_ftrace_function(struct ftrace_ops *ops)
3885 {
3886         int ret = -1;
3887
3888         mutex_lock(&ftrace_lock);
3889
3890         if (unlikely(ftrace_disabled))
3891                 goto out_unlock;
3892
3893         ret = __register_ftrace_function(ops);
3894         if (!ret)
3895                 ret = ftrace_startup(ops, 0);
3896
3897
3898  out_unlock:
3899         mutex_unlock(&ftrace_lock);
3900         return ret;
3901 }
3902 EXPORT_SYMBOL_GPL(register_ftrace_function);
3903
3904 /**
3905  * unregister_ftrace_function - unregister a function for profiling.
3906  * @ops - ops structure that holds the function to unregister
3907  *
3908  * Unregister a function that was added to be called by ftrace profiling.
3909  */
3910 int unregister_ftrace_function(struct ftrace_ops *ops)
3911 {
3912         int ret;
3913
3914         mutex_lock(&ftrace_lock);
3915         ret = __unregister_ftrace_function(ops);
3916         if (!ret)
3917                 ftrace_shutdown(ops, 0);
3918         mutex_unlock(&ftrace_lock);
3919
3920         return ret;
3921 }
3922 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
3923
3924 int
3925 ftrace_enable_sysctl(struct ctl_table *table, int write,
3926                      void __user *buffer, size_t *lenp,
3927                      loff_t *ppos)
3928 {
3929         int ret = -ENODEV;
3930
3931         mutex_lock(&ftrace_lock);
3932
3933         if (unlikely(ftrace_disabled))
3934                 goto out;
3935
3936         ret = proc_dointvec(table, write, buffer, lenp, ppos);
3937
3938         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3939                 goto out;
3940
3941         last_ftrace_enabled = !!ftrace_enabled;
3942
3943         if (ftrace_enabled) {
3944
3945                 ftrace_startup_sysctl();
3946
3947                 /* we are starting ftrace again */
3948                 if (ftrace_ops_list != &ftrace_list_end) {
3949                         if (ftrace_ops_list->next == &ftrace_list_end)
3950                                 ftrace_trace_function = ftrace_ops_list->func;
3951                         else
3952                                 ftrace_trace_function = ftrace_ops_list_func;
3953                 }
3954
3955         } else {
3956                 /* stopping ftrace calls (just send to ftrace_stub) */
3957                 ftrace_trace_function = ftrace_stub;
3958
3959                 ftrace_shutdown_sysctl();
3960         }
3961
3962  out:
3963         mutex_unlock(&ftrace_lock);
3964         return ret;
3965 }
3966
3967 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3968
3969 static int ftrace_graph_active;
3970 static struct notifier_block ftrace_suspend_notifier;
3971
3972 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3973 {
3974         return 0;
3975 }
3976
3977 /* The callbacks that hook a function */
3978 trace_func_graph_ret_t ftrace_graph_return =
3979                         (trace_func_graph_ret_t)ftrace_stub;
3980 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3981
3982 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3983 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3984 {
3985         int i;
3986         int ret = 0;
3987         unsigned long flags;
3988         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3989         struct task_struct *g, *t;
3990
3991         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3992                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3993                                         * sizeof(struct ftrace_ret_stack),
3994                                         GFP_KERNEL);
3995                 if (!ret_stack_list[i]) {
3996                         start = 0;
3997                         end = i;
3998                         ret = -ENOMEM;
3999                         goto free;
4000                 }
4001         }
4002
4003         read_lock_irqsave(&tasklist_lock, flags);
4004         do_each_thread(g, t) {
4005                 if (start == end) {
4006                         ret = -EAGAIN;
4007                         goto unlock;
4008                 }
4009
4010                 if (t->ret_stack == NULL) {
4011                         atomic_set(&t->tracing_graph_pause, 0);
4012                         atomic_set(&t->trace_overrun, 0);
4013                         t->curr_ret_stack = -1;
4014                         /* Make sure the tasks see the -1 first: */
4015                         smp_wmb();
4016                         t->ret_stack = ret_stack_list[start++];
4017                 }
4018         } while_each_thread(g, t);
4019
4020 unlock:
4021         read_unlock_irqrestore(&tasklist_lock, flags);
4022 free:
4023         for (i = start; i < end; i++)
4024                 kfree(ret_stack_list[i]);
4025         return ret;
4026 }
4027
4028 static void
4029 ftrace_graph_probe_sched_switch(void *ignore,
4030                         struct task_struct *prev, struct task_struct *next)
4031 {
4032         unsigned long long timestamp;
4033         int index;
4034
4035         /*
4036          * Does the user want to count the time a function was asleep.
4037          * If so, do not update the time stamps.
4038          */
4039         if (trace_flags & TRACE_ITER_SLEEP_TIME)
4040                 return;
4041
4042         timestamp = trace_clock_local();
4043
4044         prev->ftrace_timestamp = timestamp;
4045
4046         /* only process tasks that we timestamped */
4047         if (!next->ftrace_timestamp)
4048                 return;
4049
4050         /*
4051          * Update all the counters in next to make up for the
4052          * time next was sleeping.
4053          */
4054         timestamp -= next->ftrace_timestamp;
4055
4056         for (index = next->curr_ret_stack; index >= 0; index--)
4057                 next->ret_stack[index].calltime += timestamp;
4058 }
4059
4060 /* Allocate a return stack for each task */
4061 static int start_graph_tracing(void)
4062 {
4063         struct ftrace_ret_stack **ret_stack_list;
4064         int ret, cpu;
4065
4066         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4067                                 sizeof(struct ftrace_ret_stack *),
4068                                 GFP_KERNEL);
4069
4070         if (!ret_stack_list)
4071                 return -ENOMEM;
4072
4073         /* The cpu_boot init_task->ret_stack will never be freed */
4074         for_each_online_cpu(cpu) {
4075                 if (!idle_task(cpu)->ret_stack)
4076                         ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4077         }
4078
4079         do {
4080                 ret = alloc_retstack_tasklist(ret_stack_list);
4081         } while (ret == -EAGAIN);
4082
4083         if (!ret) {
4084                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4085                 if (ret)
4086                         pr_info("ftrace_graph: Couldn't activate tracepoint"
4087                                 " probe to kernel_sched_switch\n");
4088         }
4089
4090         kfree(ret_stack_list);
4091         return ret;
4092 }
4093
4094 /*
4095  * Hibernation protection.
4096  * The state of the current task is too much unstable during
4097  * suspend/restore to disk. We want to protect against that.
4098  */
4099 static int
4100 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4101                                                         void *unused)
4102 {
4103         switch (state) {
4104         case PM_HIBERNATION_PREPARE:
4105                 pause_graph_tracing();
4106                 break;
4107
4108         case PM_POST_HIBERNATION:
4109                 unpause_graph_tracing();
4110                 break;
4111         }
4112         return NOTIFY_DONE;
4113 }
4114
4115 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4116                         trace_func_graph_ent_t entryfunc)
4117 {
4118         int ret = 0;
4119
4120         mutex_lock(&ftrace_lock);
4121
4122         /* we currently allow only one tracer registered at a time */
4123         if (ftrace_graph_active) {
4124                 ret = -EBUSY;
4125                 goto out;
4126         }
4127
4128         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4129         register_pm_notifier(&ftrace_suspend_notifier);
4130
4131         ftrace_graph_active++;
4132         ret = start_graph_tracing();
4133         if (ret) {
4134                 ftrace_graph_active--;
4135                 goto out;
4136         }
4137
4138         ftrace_graph_return = retfunc;
4139         ftrace_graph_entry = entryfunc;
4140
4141         ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4142
4143 out:
4144         mutex_unlock(&ftrace_lock);
4145         return ret;
4146 }
4147
4148 void unregister_ftrace_graph(void)
4149 {
4150         mutex_lock(&ftrace_lock);
4151
4152         if (unlikely(!ftrace_graph_active))
4153                 goto out;
4154
4155         ftrace_graph_active--;
4156         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4157         ftrace_graph_entry = ftrace_graph_entry_stub;
4158         ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4159         unregister_pm_notifier(&ftrace_suspend_notifier);
4160         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4161
4162  out:
4163         mutex_unlock(&ftrace_lock);
4164 }
4165
4166 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4167
4168 static void
4169 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4170 {
4171         atomic_set(&t->tracing_graph_pause, 0);
4172         atomic_set(&t->trace_overrun, 0);
4173         t->ftrace_timestamp = 0;
4174         /* make curr_ret_stack visible before we add the ret_stack */
4175         smp_wmb();
4176         t->ret_stack = ret_stack;
4177 }
4178
4179 /*
4180  * Allocate a return stack for the idle task. May be the first
4181  * time through, or it may be done by CPU hotplug online.
4182  */
4183 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4184 {
4185         t->curr_ret_stack = -1;
4186         /*
4187          * The idle task has no parent, it either has its own
4188          * stack or no stack at all.
4189          */
4190         if (t->ret_stack)
4191                 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4192
4193         if (ftrace_graph_active) {
4194                 struct ftrace_ret_stack *ret_stack;
4195
4196                 ret_stack = per_cpu(idle_ret_stack, cpu);
4197                 if (!ret_stack) {
4198                    &nbs