ftrace: Simplify seqfile code
[linux-2.6.git] / kernel / trace / ftrace.c
1 /*
2  * Infrastructure for profiling code inserted by 'gcc -pg'.
3  *
4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
6  *
7  * Originally ported from the -rt patch by:
8  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
9  *
10  * Based on code in the latency_tracer, that is:
11  *
12  *  Copyright (C) 2004-2006 Ingo Molnar
13  *  Copyright (C) 2004 William Lee Irwin III
14  */
15
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/kprobes.h>
26 #include <linux/ftrace.h>
27 #include <linux/sysctl.h>
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/hash.h>
31
32 #include <trace/events/sched.h>
33
34 #include <asm/ftrace.h>
35 #include <asm/setup.h>
36
37 #include "trace_output.h"
38 #include "trace_stat.h"
39
40 #define FTRACE_WARN_ON(cond)                    \
41         do {                                    \
42                 if (WARN_ON(cond))              \
43                         ftrace_kill();          \
44         } while (0)
45
46 #define FTRACE_WARN_ON_ONCE(cond)               \
47         do {                                    \
48                 if (WARN_ON_ONCE(cond))         \
49                         ftrace_kill();          \
50         } while (0)
51
52 /* hash bits for specific function selection */
53 #define FTRACE_HASH_BITS 7
54 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
55
56 /* ftrace_enabled is a method to turn ftrace on or off */
57 int ftrace_enabled __read_mostly;
58 static int last_ftrace_enabled;
59
60 /* Quick disabling of function tracer. */
61 int function_trace_stop;
62
63 /*
64  * ftrace_disabled is set when an anomaly is discovered.
65  * ftrace_disabled is much stronger than ftrace_enabled.
66  */
67 static int ftrace_disabled __read_mostly;
68
69 static DEFINE_MUTEX(ftrace_lock);
70
71 static struct ftrace_ops ftrace_list_end __read_mostly =
72 {
73         .func           = ftrace_stub,
74 };
75
76 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
77 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
78 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
79 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
80
81 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
82 {
83         struct ftrace_ops *op = ftrace_list;
84
85         /* in case someone actually ports this to alpha! */
86         read_barrier_depends();
87
88         while (op != &ftrace_list_end) {
89                 /* silly alpha */
90                 read_barrier_depends();
91                 op->func(ip, parent_ip);
92                 op = op->next;
93         };
94 }
95
96 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
97 {
98         if (!test_tsk_trace_trace(current))
99                 return;
100
101         ftrace_pid_function(ip, parent_ip);
102 }
103
104 static void set_ftrace_pid_function(ftrace_func_t func)
105 {
106         /* do not set ftrace_pid_function to itself! */
107         if (func != ftrace_pid_func)
108                 ftrace_pid_function = func;
109 }
110
111 /**
112  * clear_ftrace_function - reset the ftrace function
113  *
114  * This NULLs the ftrace function and in essence stops
115  * tracing.  There may be lag
116  */
117 void clear_ftrace_function(void)
118 {
119         ftrace_trace_function = ftrace_stub;
120         __ftrace_trace_function = ftrace_stub;
121         ftrace_pid_function = ftrace_stub;
122 }
123
124 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
125 /*
126  * For those archs that do not test ftrace_trace_stop in their
127  * mcount call site, we need to do it from C.
128  */
129 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
130 {
131         if (function_trace_stop)
132                 return;
133
134         __ftrace_trace_function(ip, parent_ip);
135 }
136 #endif
137
138 static int __register_ftrace_function(struct ftrace_ops *ops)
139 {
140         ops->next = ftrace_list;
141         /*
142          * We are entering ops into the ftrace_list but another
143          * CPU might be walking that list. We need to make sure
144          * the ops->next pointer is valid before another CPU sees
145          * the ops pointer included into the ftrace_list.
146          */
147         smp_wmb();
148         ftrace_list = ops;
149
150         if (ftrace_enabled) {
151                 ftrace_func_t func;
152
153                 if (ops->next == &ftrace_list_end)
154                         func = ops->func;
155                 else
156                         func = ftrace_list_func;
157
158                 if (ftrace_pid_trace) {
159                         set_ftrace_pid_function(func);
160                         func = ftrace_pid_func;
161                 }
162
163                 /*
164                  * For one func, simply call it directly.
165                  * For more than one func, call the chain.
166                  */
167 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
168                 ftrace_trace_function = func;
169 #else
170                 __ftrace_trace_function = func;
171                 ftrace_trace_function = ftrace_test_stop_func;
172 #endif
173         }
174
175         return 0;
176 }
177
178 static int __unregister_ftrace_function(struct ftrace_ops *ops)
179 {
180         struct ftrace_ops **p;
181
182         /*
183          * If we are removing the last function, then simply point
184          * to the ftrace_stub.
185          */
186         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
187                 ftrace_trace_function = ftrace_stub;
188                 ftrace_list = &ftrace_list_end;
189                 return 0;
190         }
191
192         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
193                 if (*p == ops)
194                         break;
195
196         if (*p != ops)
197                 return -1;
198
199         *p = (*p)->next;
200
201         if (ftrace_enabled) {
202                 /* If we only have one func left, then call that directly */
203                 if (ftrace_list->next == &ftrace_list_end) {
204                         ftrace_func_t func = ftrace_list->func;
205
206                         if (ftrace_pid_trace) {
207                                 set_ftrace_pid_function(func);
208                                 func = ftrace_pid_func;
209                         }
210 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
211                         ftrace_trace_function = func;
212 #else
213                         __ftrace_trace_function = func;
214 #endif
215                 }
216         }
217
218         return 0;
219 }
220
221 static void ftrace_update_pid_func(void)
222 {
223         ftrace_func_t func;
224
225         if (ftrace_trace_function == ftrace_stub)
226                 return;
227
228         func = ftrace_trace_function;
229
230         if (ftrace_pid_trace) {
231                 set_ftrace_pid_function(func);
232                 func = ftrace_pid_func;
233         } else {
234                 if (func == ftrace_pid_func)
235                         func = ftrace_pid_function;
236         }
237
238 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
239         ftrace_trace_function = func;
240 #else
241         __ftrace_trace_function = func;
242 #endif
243 }
244
245 #ifdef CONFIG_FUNCTION_PROFILER
246 struct ftrace_profile {
247         struct hlist_node               node;
248         unsigned long                   ip;
249         unsigned long                   counter;
250 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
251         unsigned long long              time;
252 #endif
253 };
254
255 struct ftrace_profile_page {
256         struct ftrace_profile_page      *next;
257         unsigned long                   index;
258         struct ftrace_profile           records[];
259 };
260
261 struct ftrace_profile_stat {
262         atomic_t                        disabled;
263         struct hlist_head               *hash;
264         struct ftrace_profile_page      *pages;
265         struct ftrace_profile_page      *start;
266         struct tracer_stat              stat;
267 };
268
269 #define PROFILE_RECORDS_SIZE                                            \
270         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
271
272 #define PROFILES_PER_PAGE                                       \
273         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
274
275 static int ftrace_profile_bits __read_mostly;
276 static int ftrace_profile_enabled __read_mostly;
277
278 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
279 static DEFINE_MUTEX(ftrace_profile_lock);
280
281 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
282
283 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
284
285 static void *
286 function_stat_next(void *v, int idx)
287 {
288         struct ftrace_profile *rec = v;
289         struct ftrace_profile_page *pg;
290
291         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
292
293  again:
294         if (idx != 0)
295                 rec++;
296
297         if ((void *)rec >= (void *)&pg->records[pg->index]) {
298                 pg = pg->next;
299                 if (!pg)
300                         return NULL;
301                 rec = &pg->records[0];
302                 if (!rec->counter)
303                         goto again;
304         }
305
306         return rec;
307 }
308
309 static void *function_stat_start(struct tracer_stat *trace)
310 {
311         struct ftrace_profile_stat *stat =
312                 container_of(trace, struct ftrace_profile_stat, stat);
313
314         if (!stat || !stat->start)
315                 return NULL;
316
317         return function_stat_next(&stat->start->records[0], 0);
318 }
319
320 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
321 /* function graph compares on total time */
322 static int function_stat_cmp(void *p1, void *p2)
323 {
324         struct ftrace_profile *a = p1;
325         struct ftrace_profile *b = p2;
326
327         if (a->time < b->time)
328                 return -1;
329         if (a->time > b->time)
330                 return 1;
331         else
332                 return 0;
333 }
334 #else
335 /* not function graph compares against hits */
336 static int function_stat_cmp(void *p1, void *p2)
337 {
338         struct ftrace_profile *a = p1;
339         struct ftrace_profile *b = p2;
340
341         if (a->counter < b->counter)
342                 return -1;
343         if (a->counter > b->counter)
344                 return 1;
345         else
346                 return 0;
347 }
348 #endif
349
350 static int function_stat_headers(struct seq_file *m)
351 {
352 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
353         seq_printf(m, "  Function                               "
354                    "Hit    Time            Avg\n"
355                       "  --------                               "
356                    "---    ----            ---\n");
357 #else
358         seq_printf(m, "  Function                               Hit\n"
359                       "  --------                               ---\n");
360 #endif
361         return 0;
362 }
363
364 static int function_stat_show(struct seq_file *m, void *v)
365 {
366         struct ftrace_profile *rec = v;
367         char str[KSYM_SYMBOL_LEN];
368 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
369         static DEFINE_MUTEX(mutex);
370         static struct trace_seq s;
371         unsigned long long avg;
372 #endif
373
374         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
375         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
376
377 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
378         seq_printf(m, "    ");
379         avg = rec->time;
380         do_div(avg, rec->counter);
381
382         mutex_lock(&mutex);
383         trace_seq_init(&s);
384         trace_print_graph_duration(rec->time, &s);
385         trace_seq_puts(&s, "    ");
386         trace_print_graph_duration(avg, &s);
387         trace_print_seq(m, &s);
388         mutex_unlock(&mutex);
389 #endif
390         seq_putc(m, '\n');
391
392         return 0;
393 }
394
395 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
396 {
397         struct ftrace_profile_page *pg;
398
399         pg = stat->pages = stat->start;
400
401         while (pg) {
402                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
403                 pg->index = 0;
404                 pg = pg->next;
405         }
406
407         memset(stat->hash, 0,
408                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
409 }
410
411 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
412 {
413         struct ftrace_profile_page *pg;
414         int functions;
415         int pages;
416         int i;
417
418         /* If we already allocated, do nothing */
419         if (stat->pages)
420                 return 0;
421
422         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
423         if (!stat->pages)
424                 return -ENOMEM;
425
426 #ifdef CONFIG_DYNAMIC_FTRACE
427         functions = ftrace_update_tot_cnt;
428 #else
429         /*
430          * We do not know the number of functions that exist because
431          * dynamic tracing is what counts them. With past experience
432          * we have around 20K functions. That should be more than enough.
433          * It is highly unlikely we will execute every function in
434          * the kernel.
435          */
436         functions = 20000;
437 #endif
438
439         pg = stat->start = stat->pages;
440
441         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
442
443         for (i = 0; i < pages; i++) {
444                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
445                 if (!pg->next)
446                         goto out_free;
447                 pg = pg->next;
448         }
449
450         return 0;
451
452  out_free:
453         pg = stat->start;
454         while (pg) {
455                 unsigned long tmp = (unsigned long)pg;
456
457                 pg = pg->next;
458                 free_page(tmp);
459         }
460
461         free_page((unsigned long)stat->pages);
462         stat->pages = NULL;
463         stat->start = NULL;
464
465         return -ENOMEM;
466 }
467
468 static int ftrace_profile_init_cpu(int cpu)
469 {
470         struct ftrace_profile_stat *stat;
471         int size;
472
473         stat = &per_cpu(ftrace_profile_stats, cpu);
474
475         if (stat->hash) {
476                 /* If the profile is already created, simply reset it */
477                 ftrace_profile_reset(stat);
478                 return 0;
479         }
480
481         /*
482          * We are profiling all functions, but usually only a few thousand
483          * functions are hit. We'll make a hash of 1024 items.
484          */
485         size = FTRACE_PROFILE_HASH_SIZE;
486
487         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
488
489         if (!stat->hash)
490                 return -ENOMEM;
491
492         if (!ftrace_profile_bits) {
493                 size--;
494
495                 for (; size; size >>= 1)
496                         ftrace_profile_bits++;
497         }
498
499         /* Preallocate the function profiling pages */
500         if (ftrace_profile_pages_init(stat) < 0) {
501                 kfree(stat->hash);
502                 stat->hash = NULL;
503                 return -ENOMEM;
504         }
505
506         return 0;
507 }
508
509 static int ftrace_profile_init(void)
510 {
511         int cpu;
512         int ret = 0;
513
514         for_each_online_cpu(cpu) {
515                 ret = ftrace_profile_init_cpu(cpu);
516                 if (ret)
517                         break;
518         }
519
520         return ret;
521 }
522
523 /* interrupts must be disabled */
524 static struct ftrace_profile *
525 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
526 {
527         struct ftrace_profile *rec;
528         struct hlist_head *hhd;
529         struct hlist_node *n;
530         unsigned long key;
531
532         key = hash_long(ip, ftrace_profile_bits);
533         hhd = &stat->hash[key];
534
535         if (hlist_empty(hhd))
536                 return NULL;
537
538         hlist_for_each_entry_rcu(rec, n, hhd, node) {
539                 if (rec->ip == ip)
540                         return rec;
541         }
542
543         return NULL;
544 }
545
546 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
547                                struct ftrace_profile *rec)
548 {
549         unsigned long key;
550
551         key = hash_long(rec->ip, ftrace_profile_bits);
552         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
553 }
554
555 /*
556  * The memory is already allocated, this simply finds a new record to use.
557  */
558 static struct ftrace_profile *
559 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
560 {
561         struct ftrace_profile *rec = NULL;
562
563         /* prevent recursion (from NMIs) */
564         if (atomic_inc_return(&stat->disabled) != 1)
565                 goto out;
566
567         /*
568          * Try to find the function again since an NMI
569          * could have added it
570          */
571         rec = ftrace_find_profiled_func(stat, ip);
572         if (rec)
573                 goto out;
574
575         if (stat->pages->index == PROFILES_PER_PAGE) {
576                 if (!stat->pages->next)
577                         goto out;
578                 stat->pages = stat->pages->next;
579         }
580
581         rec = &stat->pages->records[stat->pages->index++];
582         rec->ip = ip;
583         ftrace_add_profile(stat, rec);
584
585  out:
586         atomic_dec(&stat->disabled);
587
588         return rec;
589 }
590
591 static void
592 function_profile_call(unsigned long ip, unsigned long parent_ip)
593 {
594         struct ftrace_profile_stat *stat;
595         struct ftrace_profile *rec;
596         unsigned long flags;
597
598         if (!ftrace_profile_enabled)
599                 return;
600
601         local_irq_save(flags);
602
603         stat = &__get_cpu_var(ftrace_profile_stats);
604         if (!stat->hash || !ftrace_profile_enabled)
605                 goto out;
606
607         rec = ftrace_find_profiled_func(stat, ip);
608         if (!rec) {
609                 rec = ftrace_profile_alloc(stat, ip);
610                 if (!rec)
611                         goto out;
612         }
613
614         rec->counter++;
615  out:
616         local_irq_restore(flags);
617 }
618
619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
620 static int profile_graph_entry(struct ftrace_graph_ent *trace)
621 {
622         function_profile_call(trace->func, 0);
623         return 1;
624 }
625
626 static void profile_graph_return(struct ftrace_graph_ret *trace)
627 {
628         struct ftrace_profile_stat *stat;
629         unsigned long long calltime;
630         struct ftrace_profile *rec;
631         unsigned long flags;
632
633         local_irq_save(flags);
634         stat = &__get_cpu_var(ftrace_profile_stats);
635         if (!stat->hash || !ftrace_profile_enabled)
636                 goto out;
637
638         calltime = trace->rettime - trace->calltime;
639
640         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
641                 int index;
642
643                 index = trace->depth;
644
645                 /* Append this call time to the parent time to subtract */
646                 if (index)
647                         current->ret_stack[index - 1].subtime += calltime;
648
649                 if (current->ret_stack[index].subtime < calltime)
650                         calltime -= current->ret_stack[index].subtime;
651                 else
652                         calltime = 0;
653         }
654
655         rec = ftrace_find_profiled_func(stat, trace->func);
656         if (rec)
657                 rec->time += calltime;
658
659  out:
660         local_irq_restore(flags);
661 }
662
663 static int register_ftrace_profiler(void)
664 {
665         return register_ftrace_graph(&profile_graph_return,
666                                      &profile_graph_entry);
667 }
668
669 static void unregister_ftrace_profiler(void)
670 {
671         unregister_ftrace_graph();
672 }
673 #else
674 static struct ftrace_ops ftrace_profile_ops __read_mostly =
675 {
676         .func           = function_profile_call,
677 };
678
679 static int register_ftrace_profiler(void)
680 {
681         return register_ftrace_function(&ftrace_profile_ops);
682 }
683
684 static void unregister_ftrace_profiler(void)
685 {
686         unregister_ftrace_function(&ftrace_profile_ops);
687 }
688 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
689
690 static ssize_t
691 ftrace_profile_write(struct file *filp, const char __user *ubuf,
692                      size_t cnt, loff_t *ppos)
693 {
694         unsigned long val;
695         char buf[64];           /* big enough to hold a number */
696         int ret;
697
698         if (cnt >= sizeof(buf))
699                 return -EINVAL;
700
701         if (copy_from_user(&buf, ubuf, cnt))
702                 return -EFAULT;
703
704         buf[cnt] = 0;
705
706         ret = strict_strtoul(buf, 10, &val);
707         if (ret < 0)
708                 return ret;
709
710         val = !!val;
711
712         mutex_lock(&ftrace_profile_lock);
713         if (ftrace_profile_enabled ^ val) {
714                 if (val) {
715                         ret = ftrace_profile_init();
716                         if (ret < 0) {
717                                 cnt = ret;
718                                 goto out;
719                         }
720
721                         ret = register_ftrace_profiler();
722                         if (ret < 0) {
723                                 cnt = ret;
724                                 goto out;
725                         }
726                         ftrace_profile_enabled = 1;
727                 } else {
728                         ftrace_profile_enabled = 0;
729                         /*
730                          * unregister_ftrace_profiler calls stop_machine
731                          * so this acts like an synchronize_sched.
732                          */
733                         unregister_ftrace_profiler();
734                 }
735         }
736  out:
737         mutex_unlock(&ftrace_profile_lock);
738
739         filp->f_pos += cnt;
740
741         return cnt;
742 }
743
744 static ssize_t
745 ftrace_profile_read(struct file *filp, char __user *ubuf,
746                      size_t cnt, loff_t *ppos)
747 {
748         char buf[64];           /* big enough to hold a number */
749         int r;
750
751         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
752         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
753 }
754
755 static const struct file_operations ftrace_profile_fops = {
756         .open           = tracing_open_generic,
757         .read           = ftrace_profile_read,
758         .write          = ftrace_profile_write,
759 };
760
761 /* used to initialize the real stat files */
762 static struct tracer_stat function_stats __initdata = {
763         .name           = "functions",
764         .stat_start     = function_stat_start,
765         .stat_next      = function_stat_next,
766         .stat_cmp       = function_stat_cmp,
767         .stat_headers   = function_stat_headers,
768         .stat_show      = function_stat_show
769 };
770
771 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
772 {
773         struct ftrace_profile_stat *stat;
774         struct dentry *entry;
775         char *name;
776         int ret;
777         int cpu;
778
779         for_each_possible_cpu(cpu) {
780                 stat = &per_cpu(ftrace_profile_stats, cpu);
781
782                 /* allocate enough for function name + cpu number */
783                 name = kmalloc(32, GFP_KERNEL);
784                 if (!name) {
785                         /*
786                          * The files created are permanent, if something happens
787                          * we still do not free memory.
788                          */
789                         WARN(1,
790                              "Could not allocate stat file for cpu %d\n",
791                              cpu);
792                         return;
793                 }
794                 stat->stat = function_stats;
795                 snprintf(name, 32, "function%d", cpu);
796                 stat->stat.name = name;
797                 ret = register_stat_tracer(&stat->stat);
798                 if (ret) {
799                         WARN(1,
800                              "Could not register function stat for cpu %d\n",
801                              cpu);
802                         kfree(name);
803                         return;
804                 }
805         }
806
807         entry = debugfs_create_file("function_profile_enabled", 0644,
808                                     d_tracer, NULL, &ftrace_profile_fops);
809         if (!entry)
810                 pr_warning("Could not create debugfs "
811                            "'function_profile_enabled' entry\n");
812 }
813
814 #else /* CONFIG_FUNCTION_PROFILER */
815 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
816 {
817 }
818 #endif /* CONFIG_FUNCTION_PROFILER */
819
820 /* set when tracing only a pid */
821 struct pid *ftrace_pid_trace;
822 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
823
824 #ifdef CONFIG_DYNAMIC_FTRACE
825
826 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
827 # error Dynamic ftrace depends on MCOUNT_RECORD
828 #endif
829
830 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
831
832 struct ftrace_func_probe {
833         struct hlist_node       node;
834         struct ftrace_probe_ops *ops;
835         unsigned long           flags;
836         unsigned long           ip;
837         void                    *data;
838         struct rcu_head         rcu;
839 };
840
841 enum {
842         FTRACE_ENABLE_CALLS             = (1 << 0),
843         FTRACE_DISABLE_CALLS            = (1 << 1),
844         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
845         FTRACE_ENABLE_MCOUNT            = (1 << 3),
846         FTRACE_DISABLE_MCOUNT           = (1 << 4),
847         FTRACE_START_FUNC_RET           = (1 << 5),
848         FTRACE_STOP_FUNC_RET            = (1 << 6),
849 };
850
851 static int ftrace_filtered;
852
853 static struct dyn_ftrace *ftrace_new_addrs;
854
855 static DEFINE_MUTEX(ftrace_regex_lock);
856
857 struct ftrace_page {
858         struct ftrace_page      *next;
859         int                     index;
860         struct dyn_ftrace       records[];
861 };
862
863 #define ENTRIES_PER_PAGE \
864   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
865
866 /* estimate from running different kernels */
867 #define NR_TO_INIT              10000
868
869 static struct ftrace_page       *ftrace_pages_start;
870 static struct ftrace_page       *ftrace_pages;
871
872 static struct dyn_ftrace *ftrace_free_records;
873
874 /*
875  * This is a double for. Do not use 'break' to break out of the loop,
876  * you must use a goto.
877  */
878 #define do_for_each_ftrace_rec(pg, rec)                                 \
879         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
880                 int _____i;                                             \
881                 for (_____i = 0; _____i < pg->index; _____i++) {        \
882                         rec = &pg->records[_____i];
883
884 #define while_for_each_ftrace_rec()             \
885                 }                               \
886         }
887
888 #ifdef CONFIG_KPROBES
889
890 static int frozen_record_count;
891
892 static inline void freeze_record(struct dyn_ftrace *rec)
893 {
894         if (!(rec->flags & FTRACE_FL_FROZEN)) {
895                 rec->flags |= FTRACE_FL_FROZEN;
896                 frozen_record_count++;
897         }
898 }
899
900 static inline void unfreeze_record(struct dyn_ftrace *rec)
901 {
902         if (rec->flags & FTRACE_FL_FROZEN) {
903                 rec->flags &= ~FTRACE_FL_FROZEN;
904                 frozen_record_count--;
905         }
906 }
907
908 static inline int record_frozen(struct dyn_ftrace *rec)
909 {
910         return rec->flags & FTRACE_FL_FROZEN;
911 }
912 #else
913 # define freeze_record(rec)                     ({ 0; })
914 # define unfreeze_record(rec)                   ({ 0; })
915 # define record_frozen(rec)                     ({ 0; })
916 #endif /* CONFIG_KPROBES */
917
918 static void ftrace_free_rec(struct dyn_ftrace *rec)
919 {
920         rec->freelist = ftrace_free_records;
921         ftrace_free_records = rec;
922         rec->flags |= FTRACE_FL_FREE;
923 }
924
925 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
926 {
927         struct dyn_ftrace *rec;
928
929         /* First check for freed records */
930         if (ftrace_free_records) {
931                 rec = ftrace_free_records;
932
933                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
934                         FTRACE_WARN_ON_ONCE(1);
935                         ftrace_free_records = NULL;
936                         return NULL;
937                 }
938
939                 ftrace_free_records = rec->freelist;
940                 memset(rec, 0, sizeof(*rec));
941                 return rec;
942         }
943
944         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
945                 if (!ftrace_pages->next) {
946                         /* allocate another page */
947                         ftrace_pages->next =
948                                 (void *)get_zeroed_page(GFP_KERNEL);
949                         if (!ftrace_pages->next)
950                                 return NULL;
951                 }
952                 ftrace_pages = ftrace_pages->next;
953         }
954
955         return &ftrace_pages->records[ftrace_pages->index++];
956 }
957
958 static struct dyn_ftrace *
959 ftrace_record_ip(unsigned long ip)
960 {
961         struct dyn_ftrace *rec;
962
963         if (ftrace_disabled)
964                 return NULL;
965
966         rec = ftrace_alloc_dyn_node(ip);
967         if (!rec)
968                 return NULL;
969
970         rec->ip = ip;
971         rec->newlist = ftrace_new_addrs;
972         ftrace_new_addrs = rec;
973
974         return rec;
975 }
976
977 static void print_ip_ins(const char *fmt, unsigned char *p)
978 {
979         int i;
980
981         printk(KERN_CONT "%s", fmt);
982
983         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
984                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
985 }
986
987 static void ftrace_bug(int failed, unsigned long ip)
988 {
989         switch (failed) {
990         case -EFAULT:
991                 FTRACE_WARN_ON_ONCE(1);
992                 pr_info("ftrace faulted on modifying ");
993                 print_ip_sym(ip);
994                 break;
995         case -EINVAL:
996                 FTRACE_WARN_ON_ONCE(1);
997                 pr_info("ftrace failed to modify ");
998                 print_ip_sym(ip);
999                 print_ip_ins(" actual: ", (unsigned char *)ip);
1000                 printk(KERN_CONT "\n");
1001                 break;
1002         case -EPERM:
1003                 FTRACE_WARN_ON_ONCE(1);
1004                 pr_info("ftrace faulted on writing ");
1005                 print_ip_sym(ip);
1006                 break;
1007         default:
1008                 FTRACE_WARN_ON_ONCE(1);
1009                 pr_info("ftrace faulted on unknown error ");
1010                 print_ip_sym(ip);
1011         }
1012 }
1013
1014
1015 static int
1016 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1017 {
1018         unsigned long ftrace_addr;
1019         unsigned long flag = 0UL;
1020
1021         ftrace_addr = (unsigned long)FTRACE_ADDR;
1022
1023         /*
1024          * If this record is not to be traced or we want to disable it,
1025          * then disable it.
1026          *
1027          * If we want to enable it and filtering is off, then enable it.
1028          *
1029          * If we want to enable it and filtering is on, enable it only if
1030          * it's filtered
1031          */
1032         if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1033                 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1034                         flag = FTRACE_FL_ENABLED;
1035         }
1036
1037         /* If the state of this record hasn't changed, then do nothing */
1038         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1039                 return 0;
1040
1041         if (flag) {
1042                 rec->flags |= FTRACE_FL_ENABLED;
1043                 return ftrace_make_call(rec, ftrace_addr);
1044         }
1045
1046         rec->flags &= ~FTRACE_FL_ENABLED;
1047         return ftrace_make_nop(NULL, rec, ftrace_addr);
1048 }
1049
1050 static void ftrace_replace_code(int enable)
1051 {
1052         struct dyn_ftrace *rec;
1053         struct ftrace_page *pg;
1054         int failed;
1055
1056         do_for_each_ftrace_rec(pg, rec) {
1057                 /*
1058                  * Skip over free records, records that have
1059                  * failed and not converted.
1060                  */
1061                 if (rec->flags & FTRACE_FL_FREE ||
1062                     rec->flags & FTRACE_FL_FAILED ||
1063                     !(rec->flags & FTRACE_FL_CONVERTED))
1064                         continue;
1065
1066                 /* ignore updates to this record's mcount site */
1067                 if (get_kprobe((void *)rec->ip)) {
1068                         freeze_record(rec);
1069                         continue;
1070                 } else {
1071                         unfreeze_record(rec);
1072                 }
1073
1074                 failed = __ftrace_replace_code(rec, enable);
1075                 if (failed) {
1076                         rec->flags |= FTRACE_FL_FAILED;
1077                         if ((system_state == SYSTEM_BOOTING) ||
1078                             !core_kernel_text(rec->ip)) {
1079                                 ftrace_free_rec(rec);
1080                                 } else {
1081                                 ftrace_bug(failed, rec->ip);
1082                                         /* Stop processing */
1083                                         return;
1084                                 }
1085                 }
1086         } while_for_each_ftrace_rec();
1087 }
1088
1089 static int
1090 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1091 {
1092         unsigned long ip;
1093         int ret;
1094
1095         ip = rec->ip;
1096
1097         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1098         if (ret) {
1099                 ftrace_bug(ret, ip);
1100                 rec->flags |= FTRACE_FL_FAILED;
1101                 return 0;
1102         }
1103         return 1;
1104 }
1105
1106 /*
1107  * archs can override this function if they must do something
1108  * before the modifying code is performed.
1109  */
1110 int __weak ftrace_arch_code_modify_prepare(void)
1111 {
1112         return 0;
1113 }
1114
1115 /*
1116  * archs can override this function if they must do something
1117  * after the modifying code is performed.
1118  */
1119 int __weak ftrace_arch_code_modify_post_process(void)
1120 {
1121         return 0;
1122 }
1123
1124 static int __ftrace_modify_code(void *data)
1125 {
1126         int *command = data;
1127
1128         if (*command & FTRACE_ENABLE_CALLS)
1129                 ftrace_replace_code(1);
1130         else if (*command & FTRACE_DISABLE_CALLS)
1131                 ftrace_replace_code(0);
1132
1133         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1134                 ftrace_update_ftrace_func(ftrace_trace_function);
1135
1136         if (*command & FTRACE_START_FUNC_RET)
1137                 ftrace_enable_ftrace_graph_caller();
1138         else if (*command & FTRACE_STOP_FUNC_RET)
1139                 ftrace_disable_ftrace_graph_caller();
1140
1141         return 0;
1142 }
1143
1144 static void ftrace_run_update_code(int command)
1145 {
1146         int ret;
1147
1148         ret = ftrace_arch_code_modify_prepare();
1149         FTRACE_WARN_ON(ret);
1150         if (ret)
1151                 return;
1152
1153         stop_machine(__ftrace_modify_code, &command, NULL);
1154
1155         ret = ftrace_arch_code_modify_post_process();
1156         FTRACE_WARN_ON(ret);
1157 }
1158
1159 static ftrace_func_t saved_ftrace_func;
1160 static int ftrace_start_up;
1161
1162 static void ftrace_startup_enable(int command)
1163 {
1164         if (saved_ftrace_func != ftrace_trace_function) {
1165                 saved_ftrace_func = ftrace_trace_function;
1166                 command |= FTRACE_UPDATE_TRACE_FUNC;
1167         }
1168
1169         if (!command || !ftrace_enabled)
1170                 return;
1171
1172         ftrace_run_update_code(command);
1173 }
1174
1175 static void ftrace_startup(int command)
1176 {
1177         if (unlikely(ftrace_disabled))
1178                 return;
1179
1180         ftrace_start_up++;
1181         command |= FTRACE_ENABLE_CALLS;
1182
1183         ftrace_startup_enable(command);
1184 }
1185
1186 static void ftrace_shutdown(int command)
1187 {
1188         if (unlikely(ftrace_disabled))
1189                 return;
1190
1191         ftrace_start_up--;
1192         /*
1193          * Just warn in case of unbalance, no need to kill ftrace, it's not
1194          * critical but the ftrace_call callers may be never nopped again after
1195          * further ftrace uses.
1196          */
1197         WARN_ON_ONCE(ftrace_start_up < 0);
1198
1199         if (!ftrace_start_up)
1200                 command |= FTRACE_DISABLE_CALLS;
1201
1202         if (saved_ftrace_func != ftrace_trace_function) {
1203                 saved_ftrace_func = ftrace_trace_function;
1204                 command |= FTRACE_UPDATE_TRACE_FUNC;
1205         }
1206
1207         if (!command || !ftrace_enabled)
1208                 return;
1209
1210         ftrace_run_update_code(command);
1211 }
1212
1213 static void ftrace_startup_sysctl(void)
1214 {
1215         int command = FTRACE_ENABLE_MCOUNT;
1216
1217         if (unlikely(ftrace_disabled))
1218                 return;
1219
1220         /* Force update next time */
1221         saved_ftrace_func = NULL;
1222         /* ftrace_start_up is true if we want ftrace running */
1223         if (ftrace_start_up)
1224                 command |= FTRACE_ENABLE_CALLS;
1225
1226         ftrace_run_update_code(command);
1227 }
1228
1229 static void ftrace_shutdown_sysctl(void)
1230 {
1231         int command = FTRACE_DISABLE_MCOUNT;
1232
1233         if (unlikely(ftrace_disabled))
1234                 return;
1235
1236         /* ftrace_start_up is true if ftrace is running */
1237         if (ftrace_start_up)
1238                 command |= FTRACE_DISABLE_CALLS;
1239
1240         ftrace_run_update_code(command);
1241 }
1242
1243 static cycle_t          ftrace_update_time;
1244 static unsigned long    ftrace_update_cnt;
1245 unsigned long           ftrace_update_tot_cnt;
1246
1247 static int ftrace_update_code(struct module *mod)
1248 {
1249         struct dyn_ftrace *p;
1250         cycle_t start, stop;
1251
1252         start = ftrace_now(raw_smp_processor_id());
1253         ftrace_update_cnt = 0;
1254
1255         while (ftrace_new_addrs) {
1256
1257                 /* If something went wrong, bail without enabling anything */
1258                 if (unlikely(ftrace_disabled))
1259                         return -1;
1260
1261                 p = ftrace_new_addrs;
1262                 ftrace_new_addrs = p->newlist;
1263                 p->flags = 0L;
1264
1265                 /* convert record (i.e, patch mcount-call with NOP) */
1266                 if (ftrace_code_disable(mod, p)) {
1267                         p->flags |= FTRACE_FL_CONVERTED;
1268                         ftrace_update_cnt++;
1269                 } else
1270                         ftrace_free_rec(p);
1271         }
1272
1273         stop = ftrace_now(raw_smp_processor_id());
1274         ftrace_update_time = stop - start;
1275         ftrace_update_tot_cnt += ftrace_update_cnt;
1276
1277         return 0;
1278 }
1279
1280 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1281 {
1282         struct ftrace_page *pg;
1283         int cnt;
1284         int i;
1285
1286         /* allocate a few pages */
1287         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1288         if (!ftrace_pages_start)
1289                 return -1;
1290
1291         /*
1292          * Allocate a few more pages.
1293          *
1294          * TODO: have some parser search vmlinux before
1295          *   final linking to find all calls to ftrace.
1296          *   Then we can:
1297          *    a) know how many pages to allocate.
1298          *     and/or
1299          *    b) set up the table then.
1300          *
1301          *  The dynamic code is still necessary for
1302          *  modules.
1303          */
1304
1305         pg = ftrace_pages = ftrace_pages_start;
1306
1307         cnt = num_to_init / ENTRIES_PER_PAGE;
1308         pr_info("ftrace: allocating %ld entries in %d pages\n",
1309                 num_to_init, cnt + 1);
1310
1311         for (i = 0; i < cnt; i++) {
1312                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1313
1314                 /* If we fail, we'll try later anyway */
1315                 if (!pg->next)
1316                         break;
1317
1318                 pg = pg->next;
1319         }
1320
1321         return 0;
1322 }
1323
1324 enum {
1325         FTRACE_ITER_FILTER      = (1 << 0),
1326         FTRACE_ITER_CONT        = (1 << 1),
1327         FTRACE_ITER_NOTRACE     = (1 << 2),
1328         FTRACE_ITER_FAILURES    = (1 << 3),
1329         FTRACE_ITER_PRINTALL    = (1 << 4),
1330         FTRACE_ITER_HASH        = (1 << 5),
1331 };
1332
1333 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1334
1335 struct ftrace_iterator {
1336         struct ftrace_page      *pg;
1337         int                     hidx;
1338         int                     idx;
1339         unsigned                flags;
1340         unsigned char           buffer[FTRACE_BUFF_MAX+1];
1341         unsigned                buffer_idx;
1342 };
1343
1344 static void *
1345 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1346 {
1347         struct ftrace_iterator *iter = m->private;
1348         struct hlist_node *hnd = v;
1349         struct hlist_head *hhd;
1350
1351         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1352
1353         (*pos)++;
1354
1355  retry:
1356         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1357                 return NULL;
1358
1359         hhd = &ftrace_func_hash[iter->hidx];
1360
1361         if (hlist_empty(hhd)) {
1362                 iter->hidx++;
1363                 hnd = NULL;
1364                 goto retry;
1365         }
1366
1367         if (!hnd)
1368                 hnd = hhd->first;
1369         else {
1370                 hnd = hnd->next;
1371                 if (!hnd) {
1372                         iter->hidx++;
1373                         goto retry;
1374                 }
1375         }
1376
1377         return hnd;
1378 }
1379
1380 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1381 {
1382         struct ftrace_iterator *iter = m->private;
1383         void *p = NULL;
1384         loff_t l;
1385
1386         if (!(iter->flags & FTRACE_ITER_HASH))
1387                 *pos = 0;
1388
1389         iter->flags |= FTRACE_ITER_HASH;
1390
1391         iter->hidx = 0;
1392         for (l = 0; l <= *pos; ) {
1393                 p = t_hash_next(m, p, &l);
1394                 if (!p)
1395                         break;
1396         }
1397         return p;
1398 }
1399
1400 static int t_hash_show(struct seq_file *m, void *v)
1401 {
1402         struct ftrace_func_probe *rec;
1403         struct hlist_node *hnd = v;
1404
1405         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1406
1407         if (rec->ops->print)
1408                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1409
1410         seq_printf(m, "%pf:%pf", (void *)rec->ip, (void *)rec->ops->func);
1411
1412         if (rec->data)
1413                 seq_printf(m, ":%p", rec->data);
1414         seq_putc(m, '\n');
1415
1416         return 0;
1417 }
1418
1419 static void *
1420 t_next(struct seq_file *m, void *v, loff_t *pos)
1421 {
1422         struct ftrace_iterator *iter = m->private;
1423         struct dyn_ftrace *rec = NULL;
1424
1425         if (iter->flags & FTRACE_ITER_HASH)
1426                 return t_hash_next(m, v, pos);
1427
1428         (*pos)++;
1429
1430         if (iter->flags & FTRACE_ITER_PRINTALL)
1431                 return NULL;
1432
1433  retry:
1434         if (iter->idx >= iter->pg->index) {
1435                 if (iter->pg->next) {
1436                         iter->pg = iter->pg->next;
1437                         iter->idx = 0;
1438                         goto retry;
1439                 }
1440         } else {
1441                 rec = &iter->pg->records[iter->idx++];
1442                 if ((rec->flags & FTRACE_FL_FREE) ||
1443
1444                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
1445                      (rec->flags & FTRACE_FL_FAILED)) ||
1446
1447                     ((iter->flags & FTRACE_ITER_FAILURES) &&
1448                      !(rec->flags & FTRACE_FL_FAILED)) ||
1449
1450                     ((iter->flags & FTRACE_ITER_FILTER) &&
1451                      !(rec->flags & FTRACE_FL_FILTER)) ||
1452
1453                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
1454                      !(rec->flags & FTRACE_FL_NOTRACE))) {
1455                         rec = NULL;
1456                         goto retry;
1457                 }
1458         }
1459
1460         return rec;
1461 }
1462
1463 static void *t_start(struct seq_file *m, loff_t *pos)
1464 {
1465         struct ftrace_iterator *iter = m->private;
1466         void *p = NULL;
1467         loff_t l;
1468
1469         mutex_lock(&ftrace_lock);
1470         /*
1471          * For set_ftrace_filter reading, if we have the filter
1472          * off, we can short cut and just print out that all
1473          * functions are enabled.
1474          */
1475         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1476                 if (*pos > 0)
1477                         return t_hash_start(m, pos);
1478                 iter->flags |= FTRACE_ITER_PRINTALL;
1479                 return iter;
1480         }
1481
1482         if (iter->flags & FTRACE_ITER_HASH)
1483                 return t_hash_start(m, pos);
1484
1485         iter->pg = ftrace_pages_start;
1486         iter->idx = 0;
1487         for (l = 0; l <= *pos; ) {
1488                 p = t_next(m, p, &l);
1489                 if (!p)
1490                         break;
1491         }
1492
1493         if (!p && iter->flags & FTRACE_ITER_FILTER)
1494                 return t_hash_start(m, pos);
1495
1496         return p;
1497 }
1498
1499 static void t_stop(struct seq_file *m, void *p)
1500 {
1501         mutex_unlock(&ftrace_lock);
1502 }
1503
1504 static int t_show(struct seq_file *m, void *v)
1505 {
1506         struct ftrace_iterator *iter = m->private;
1507         struct dyn_ftrace *rec = v;
1508
1509         if (iter->flags & FTRACE_ITER_HASH)
1510                 return t_hash_show(m, v);
1511
1512         if (iter->flags & FTRACE_ITER_PRINTALL) {
1513                 seq_printf(m, "#### all functions enabled ####\n");
1514                 return 0;
1515         }
1516
1517         if (!rec)
1518                 return 0;
1519
1520         seq_printf(m, "%pf\n", (void *)rec->ip);
1521
1522         return 0;
1523 }
1524
1525 static struct seq_operations show_ftrace_seq_ops = {
1526         .start = t_start,
1527         .next = t_next,
1528         .stop = t_stop,
1529         .show = t_show,
1530 };
1531
1532 static int
1533 ftrace_avail_open(struct inode *inode, struct file *file)
1534 {
1535         struct ftrace_iterator *iter;
1536         int ret;
1537
1538         if (unlikely(ftrace_disabled))
1539                 return -ENODEV;
1540
1541         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1542         if (!iter)
1543                 return -ENOMEM;
1544
1545         iter->pg = ftrace_pages_start;
1546
1547         ret = seq_open(file, &show_ftrace_seq_ops);
1548         if (!ret) {
1549                 struct seq_file *m = file->private_data;
1550
1551                 m->private = iter;
1552         } else {
1553                 kfree(iter);
1554         }
1555
1556         return ret;
1557 }
1558
1559 static int
1560 ftrace_failures_open(struct inode *inode, struct file *file)
1561 {
1562         int ret;
1563         struct seq_file *m;
1564         struct ftrace_iterator *iter;
1565
1566         ret = ftrace_avail_open(inode, file);
1567         if (!ret) {
1568                 m = (struct seq_file *)file->private_data;
1569                 iter = (struct ftrace_iterator *)m->private;
1570                 iter->flags = FTRACE_ITER_FAILURES;
1571         }
1572
1573         return ret;
1574 }
1575
1576
1577 static void ftrace_filter_reset(int enable)
1578 {
1579         struct ftrace_page *pg;
1580         struct dyn_ftrace *rec;
1581         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1582
1583         mutex_lock(&ftrace_lock);
1584         if (enable)
1585                 ftrace_filtered = 0;
1586         do_for_each_ftrace_rec(pg, rec) {
1587                 if (rec->flags & FTRACE_FL_FAILED)
1588                         continue;
1589                 rec->flags &= ~type;
1590         } while_for_each_ftrace_rec();
1591         mutex_unlock(&ftrace_lock);
1592 }
1593
1594 static int
1595 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1596 {
1597         struct ftrace_iterator *iter;
1598         int ret = 0;
1599
1600         if (unlikely(ftrace_disabled))
1601                 return -ENODEV;
1602
1603         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1604         if (!iter)
1605                 return -ENOMEM;
1606
1607         mutex_lock(&ftrace_regex_lock);
1608         if ((file->f_mode & FMODE_WRITE) &&
1609             (file->f_flags & O_TRUNC))
1610                 ftrace_filter_reset(enable);
1611
1612         if (file->f_mode & FMODE_READ) {
1613                 iter->pg = ftrace_pages_start;
1614                 iter->flags = enable ? FTRACE_ITER_FILTER :
1615                         FTRACE_ITER_NOTRACE;
1616
1617                 ret = seq_open(file, &show_ftrace_seq_ops);
1618                 if (!ret) {
1619                         struct seq_file *m = file->private_data;
1620                         m->private = iter;
1621                 } else
1622                         kfree(iter);
1623         } else
1624                 file->private_data = iter;
1625         mutex_unlock(&ftrace_regex_lock);
1626
1627         return ret;
1628 }
1629
1630 static int
1631 ftrace_filter_open(struct inode *inode, struct file *file)
1632 {
1633         return ftrace_regex_open(inode, file, 1);
1634 }
1635
1636 static int
1637 ftrace_notrace_open(struct inode *inode, struct file *file)
1638 {
1639         return ftrace_regex_open(inode, file, 0);
1640 }
1641
1642 static loff_t
1643 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1644 {
1645         loff_t ret;
1646
1647         if (file->f_mode & FMODE_READ)
1648                 ret = seq_lseek(file, offset, origin);
1649         else
1650                 file->f_pos = ret = 1;
1651
1652         return ret;
1653 }
1654
1655 enum {
1656         MATCH_FULL,
1657         MATCH_FRONT_ONLY,
1658         MATCH_MIDDLE_ONLY,
1659         MATCH_END_ONLY,
1660 };
1661
1662 /*
1663  * (static function - no need for kernel doc)
1664  *
1665  * Pass in a buffer containing a glob and this function will
1666  * set search to point to the search part of the buffer and
1667  * return the type of search it is (see enum above).
1668  * This does modify buff.
1669  *
1670  * Returns enum type.
1671  *  search returns the pointer to use for comparison.
1672  *  not returns 1 if buff started with a '!'
1673  *     0 otherwise.
1674  */
1675 static int
1676 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1677 {
1678         int type = MATCH_FULL;
1679         int i;
1680
1681         if (buff[0] == '!') {
1682                 *not = 1;
1683                 buff++;
1684                 len--;
1685         } else
1686                 *not = 0;
1687
1688         *search = buff;
1689
1690         for (i = 0; i < len; i++) {
1691                 if (buff[i] == '*') {
1692                         if (!i) {
1693                                 *search = buff + 1;
1694                                 type = MATCH_END_ONLY;
1695                         } else {
1696                                 if (type == MATCH_END_ONLY)
1697                                         type = MATCH_MIDDLE_ONLY;
1698                                 else
1699                                         type = MATCH_FRONT_ONLY;
1700                                 buff[i] = 0;
1701                                 break;
1702                         }
1703                 }
1704         }
1705
1706         return type;
1707 }
1708
1709 static int ftrace_match(char *str, char *regex, int len, int type)
1710 {
1711         int matched = 0;
1712         char *ptr;
1713
1714         switch (type) {
1715         case MATCH_FULL:
1716                 if (strcmp(str, regex) == 0)
1717                         matched = 1;
1718                 break;
1719         case MATCH_FRONT_ONLY:
1720                 if (strncmp(str, regex, len) == 0)
1721                         matched = 1;
1722                 break;
1723         case MATCH_MIDDLE_ONLY:
1724                 if (strstr(str, regex))
1725                         matched = 1;
1726                 break;
1727         case MATCH_END_ONLY:
1728                 ptr = strstr(str, regex);
1729                 if (ptr && (ptr[len] == 0))
1730                         matched = 1;
1731                 break;
1732         }
1733
1734         return matched;
1735 }
1736
1737 static int
1738 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1739 {
1740         char str[KSYM_SYMBOL_LEN];
1741
1742         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1743         return ftrace_match(str, regex, len, type);
1744 }
1745
1746 static void ftrace_match_records(char *buff, int len, int enable)
1747 {
1748         unsigned int search_len;
1749         struct ftrace_page *pg;
1750         struct dyn_ftrace *rec;
1751         unsigned long flag;
1752         char *search;
1753         int type;
1754         int not;
1755
1756         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1757         type = ftrace_setup_glob(buff, len, &search, &not);
1758
1759         search_len = strlen(search);
1760
1761         mutex_lock(&ftrace_lock);
1762         do_for_each_ftrace_rec(pg, rec) {
1763
1764                 if (rec->flags & FTRACE_FL_FAILED)
1765                         continue;
1766
1767                 if (ftrace_match_record(rec, search, search_len, type)) {
1768                         if (not)
1769                                 rec->flags &= ~flag;
1770                         else
1771                                 rec->flags |= flag;
1772                 }
1773                 /*
1774                  * Only enable filtering if we have a function that
1775                  * is filtered on.
1776                  */
1777                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1778                         ftrace_filtered = 1;
1779         } while_for_each_ftrace_rec();
1780         mutex_unlock(&ftrace_lock);
1781 }
1782
1783 static int
1784 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1785                            char *regex, int len, int type)
1786 {
1787         char str[KSYM_SYMBOL_LEN];
1788         char *modname;
1789
1790         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1791
1792         if (!modname || strcmp(modname, mod))
1793                 return 0;
1794
1795         /* blank search means to match all funcs in the mod */
1796         if (len)
1797                 return ftrace_match(str, regex, len, type);
1798         else
1799                 return 1;
1800 }
1801
1802 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1803 {
1804         unsigned search_len = 0;
1805         struct ftrace_page *pg;
1806         struct dyn_ftrace *rec;
1807         int type = MATCH_FULL;
1808         char *search = buff;
1809         unsigned long flag;
1810         int not = 0;
1811
1812         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1813
1814         /* blank or '*' mean the same */
1815         if (strcmp(buff, "*") == 0)
1816                 buff[0] = 0;
1817
1818         /* handle the case of 'dont filter this module' */
1819         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1820                 buff[0] = 0;
1821                 not = 1;
1822         }
1823
1824         if (strlen(buff)) {
1825                 type = ftrace_setup_glob(buff, strlen(buff), &search, &not);
1826                 search_len = strlen(search);
1827         }
1828
1829         mutex_lock(&ftrace_lock);
1830         do_for_each_ftrace_rec(pg, rec) {
1831
1832                 if (rec->flags & FTRACE_FL_FAILED)
1833                         continue;
1834
1835                 if (ftrace_match_module_record(rec, mod,
1836                                                search, search_len, type)) {
1837                         if (not)
1838                                 rec->flags &= ~flag;
1839                         else
1840                                 rec->flags |= flag;
1841                 }
1842                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1843                         ftrace_filtered = 1;
1844
1845         } while_for_each_ftrace_rec();
1846         mutex_unlock(&ftrace_lock);
1847 }
1848
1849 /*
1850  * We register the module command as a template to show others how
1851  * to register the a command as well.
1852  */
1853
1854 static int
1855 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1856 {
1857         char *mod;
1858
1859         /*
1860          * cmd == 'mod' because we only registered this func
1861          * for the 'mod' ftrace_func_command.
1862          * But if you register one func with multiple commands,
1863          * you can tell which command was used by the cmd
1864          * parameter.
1865          */
1866
1867         /* we must have a module name */
1868         if (!param)
1869                 return -EINVAL;
1870
1871         mod = strsep(&param, ":");
1872         if (!strlen(mod))
1873                 return -EINVAL;
1874
1875         ftrace_match_module_records(func, mod, enable);
1876         return 0;
1877 }
1878
1879 static struct ftrace_func_command ftrace_mod_cmd = {
1880         .name                   = "mod",
1881         .func                   = ftrace_mod_callback,
1882 };
1883
1884 static int __init ftrace_mod_cmd_init(void)
1885 {
1886         return register_ftrace_command(&ftrace_mod_cmd);
1887 }
1888 device_initcall(ftrace_mod_cmd_init);
1889
1890 static void
1891 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1892 {
1893         struct ftrace_func_probe *entry;
1894         struct hlist_head *hhd;
1895         struct hlist_node *n;
1896         unsigned long key;
1897         int resched;
1898
1899         key = hash_long(ip, FTRACE_HASH_BITS);
1900
1901         hhd = &ftrace_func_hash[key];
1902
1903         if (hlist_empty(hhd))
1904                 return;
1905
1906         /*
1907          * Disable preemption for these calls to prevent a RCU grace
1908          * period. This syncs the hash iteration and freeing of items
1909          * on the hash. rcu_read_lock is too dangerous here.
1910          */
1911         resched = ftrace_preempt_disable();
1912         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1913                 if (entry->ip == ip)
1914                         entry->ops->func(ip, parent_ip, &entry->data);
1915         }
1916         ftrace_preempt_enable(resched);
1917 }
1918
1919 static struct ftrace_ops trace_probe_ops __read_mostly =
1920 {
1921         .func           = function_trace_probe_call,
1922 };
1923
1924 static int ftrace_probe_registered;
1925
1926 static void __enable_ftrace_function_probe(void)
1927 {
1928         int i;
1929
1930         if (ftrace_probe_registered)
1931                 return;
1932
1933         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1934                 struct hlist_head *hhd = &ftrace_func_hash[i];
1935                 if (hhd->first)
1936                         break;
1937         }
1938         /* Nothing registered? */
1939         if (i == FTRACE_FUNC_HASHSIZE)
1940                 return;
1941
1942         __register_ftrace_function(&trace_probe_ops);
1943         ftrace_startup(0);
1944         ftrace_probe_registered = 1;
1945 }
1946
1947 static void __disable_ftrace_function_probe(void)
1948 {
1949         int i;
1950
1951         if (!ftrace_probe_registered)
1952                 return;
1953
1954         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1955                 struct hlist_head *hhd = &ftrace_func_hash[i];
1956                 if (hhd->first)
1957                         return;
1958         }
1959
1960         /* no more funcs left */
1961         __unregister_ftrace_function(&trace_probe_ops);
1962         ftrace_shutdown(0);
1963         ftrace_probe_registered = 0;
1964 }
1965
1966
1967 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1968 {
1969         struct ftrace_func_probe *entry =
1970                 container_of(rhp, struct ftrace_func_probe, rcu);
1971
1972         if (entry->ops->free)
1973                 entry->ops->free(&entry->data);
1974         kfree(entry);
1975 }
1976
1977
1978 int
1979 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1980                               void *data)
1981 {
1982         struct ftrace_func_probe *entry;
1983         struct ftrace_page *pg;
1984         struct dyn_ftrace *rec;
1985         int type, len, not;
1986         unsigned long key;
1987         int count = 0;
1988         char *search;
1989
1990         type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
1991         len = strlen(search);
1992
1993         /* we do not support '!' for function probes */
1994         if (WARN_ON(not))
1995                 return -EINVAL;
1996
1997         mutex_lock(&ftrace_lock);
1998         do_for_each_ftrace_rec(pg, rec) {
1999
2000                 if (rec->flags & FTRACE_FL_FAILED)
2001                         continue;
2002
2003                 if (!ftrace_match_record(rec, search, len, type))
2004                         continue;
2005
2006                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2007                 if (!entry) {
2008                         /* If we did not process any, then return error */
2009                         if (!count)
2010                                 count = -ENOMEM;
2011                         goto out_unlock;
2012                 }
2013
2014                 count++;
2015
2016                 entry->data = data;
2017
2018                 /*
2019                  * The caller might want to do something special
2020                  * for each function we find. We call the callback
2021                  * to give the caller an opportunity to do so.
2022                  */
2023                 if (ops->callback) {
2024                         if (ops->callback(rec->ip, &entry->data) < 0) {
2025                                 /* caller does not like this func */
2026                                 kfree(entry);
2027                                 continue;
2028                         }
2029                 }
2030
2031                 entry->ops = ops;
2032                 entry->ip = rec->ip;
2033
2034                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2035                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2036
2037         } while_for_each_ftrace_rec();
2038         __enable_ftrace_function_probe();
2039
2040  out_unlock:
2041         mutex_unlock(&ftrace_lock);
2042
2043         return count;
2044 }
2045
2046 enum {
2047         PROBE_TEST_FUNC         = 1,
2048         PROBE_TEST_DATA         = 2
2049 };
2050
2051 static void
2052 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2053                                   void *data, int flags)
2054 {
2055         struct ftrace_func_probe *entry;
2056         struct hlist_node *n, *tmp;
2057         char str[KSYM_SYMBOL_LEN];
2058         int type = MATCH_FULL;
2059         int i, len = 0;
2060         char *search;
2061
2062         if (glob && (strcmp(glob, "*") || !strlen(glob)))
2063                 glob = NULL;
2064         else {
2065                 int not;
2066
2067                 type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
2068                 len = strlen(search);
2069
2070                 /* we do not support '!' for function probes */
2071                 if (WARN_ON(not))
2072                         return;
2073         }
2074
2075         mutex_lock(&ftrace_lock);
2076         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2077                 struct hlist_head *hhd = &ftrace_func_hash[i];
2078
2079                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2080
2081                         /* break up if statements for readability */
2082                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2083                                 continue;
2084
2085                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2086                                 continue;
2087
2088                         /* do this last, since it is the most expensive */
2089                         if (glob) {
2090                                 kallsyms_lookup(entry->ip, NULL, NULL,
2091                                                 NULL, str);
2092                                 if (!ftrace_match(str, glob, len, type))
2093                                         continue;
2094                         }
2095
2096                         hlist_del(&entry->node);
2097                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2098                 }
2099         }
2100         __disable_ftrace_function_probe();
2101         mutex_unlock(&ftrace_lock);
2102 }
2103
2104 void
2105 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2106                                 void *data)
2107 {
2108         __unregister_ftrace_function_probe(glob, ops, data,
2109                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2110 }
2111
2112 void
2113 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2114 {
2115         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2116 }
2117
2118 void unregister_ftrace_function_probe_all(char *glob)
2119 {
2120         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2121 }
2122
2123 static LIST_HEAD(ftrace_commands);
2124 static DEFINE_MUTEX(ftrace_cmd_mutex);
2125
2126 int register_ftrace_command(struct ftrace_func_command *cmd)
2127 {
2128         struct ftrace_func_command *p;
2129         int ret = 0;
2130
2131         mutex_lock(&ftrace_cmd_mutex);
2132         list_for_each_entry(p, &ftrace_commands, list) {
2133                 if (strcmp(cmd->name, p->name) == 0) {
2134                         ret = -EBUSY;
2135                         goto out_unlock;
2136                 }
2137         }
2138         list_add(&cmd->list, &ftrace_commands);
2139  out_unlock:
2140         mutex_unlock(&ftrace_cmd_mutex);
2141
2142         return ret;
2143 }
2144
2145 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2146 {
2147         struct ftrace_func_command *p, *n;
2148         int ret = -ENODEV;
2149
2150         mutex_lock(&ftrace_cmd_mutex);
2151         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2152                 if (strcmp(cmd->name, p->name) == 0) {
2153                         ret = 0;
2154                         list_del_init(&p->list);
2155                         goto out_unlock;
2156                 }
2157         }
2158  out_unlock:
2159         mutex_unlock(&ftrace_cmd_mutex);
2160
2161         return ret;
2162 }
2163
2164 static int ftrace_process_regex(char *buff, int len, int enable)
2165 {
2166         char *func, *command, *next = buff;
2167         struct ftrace_func_command *p;
2168         int ret = -EINVAL;
2169
2170         func = strsep(&next, ":");
2171
2172         if (!next) {
2173                 ftrace_match_records(func, len, enable);
2174                 return 0;
2175         }
2176
2177         /* command found */
2178
2179         command = strsep(&next, ":");
2180
2181         mutex_lock(&ftrace_cmd_mutex);
2182         list_for_each_entry(p, &ftrace_commands, list) {
2183                 if (strcmp(p->name, command) == 0) {
2184                         ret = p->func(func, command, next, enable);
2185                         goto out_unlock;
2186                 }
2187         }
2188  out_unlock:
2189         mutex_unlock(&ftrace_cmd_mutex);
2190
2191         return ret;
2192 }
2193
2194 static ssize_t
2195 ftrace_regex_write(struct file *file, const char __user *ubuf,
2196                    size_t cnt, loff_t *ppos, int enable)
2197 {
2198         struct ftrace_iterator *iter;
2199         char ch;
2200         size_t read = 0;
2201         ssize_t ret;
2202
2203         if (!cnt || cnt < 0)
2204                 return 0;
2205
2206         mutex_lock(&ftrace_regex_lock);
2207
2208         if (file->f_mode & FMODE_READ) {
2209                 struct seq_file *m = file->private_data;
2210                 iter = m->private;
2211         } else
2212                 iter = file->private_data;
2213
2214         if (!*ppos) {
2215                 iter->flags &= ~FTRACE_ITER_CONT;
2216                 iter->buffer_idx = 0;
2217         }
2218
2219         ret = get_user(ch, ubuf++);
2220         if (ret)
2221                 goto out;
2222         read++;
2223         cnt--;
2224
2225         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
2226                 /* skip white space */
2227                 while (cnt && isspace(ch)) {
2228                         ret = get_user(ch, ubuf++);
2229                         if (ret)
2230                                 goto out;
2231                         read++;
2232                         cnt--;
2233                 }
2234
2235                 if (isspace(ch)) {
2236                         file->f_pos += read;
2237                         ret = read;
2238                         goto out;
2239                 }
2240
2241                 iter->buffer_idx = 0;
2242         }
2243
2244         while (cnt && !isspace(ch)) {
2245                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
2246                         iter->buffer[iter->buffer_idx++] = ch;
2247                 else {
2248                         ret = -EINVAL;
2249                         goto out;
2250                 }
2251                 ret = get_user(ch, ubuf++);
2252                 if (ret)
2253                         goto out;
2254                 read++;
2255                 cnt--;
2256         }
2257
2258         if (isspace(ch)) {
2259                 iter->buffer[iter->buffer_idx] = 0;
2260                 ret = ftrace_process_regex(iter->buffer,
2261                                            iter->buffer_idx, enable);
2262                 if (ret)
2263                         goto out;
2264                 iter->buffer_idx = 0;
2265         } else
2266                 iter->flags |= FTRACE_ITER_CONT;
2267
2268
2269         file->f_pos += read;
2270
2271         ret = read;
2272  out:
2273         mutex_unlock(&ftrace_regex_lock);
2274
2275         return ret;
2276 }
2277
2278 static ssize_t
2279 ftrace_filter_write(struct file *file, const char __user *ubuf,
2280                     size_t cnt, loff_t *ppos)
2281 {
2282         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2283 }
2284
2285 static ssize_t
2286 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2287                      size_t cnt, loff_t *ppos)
2288 {
2289         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2290 }
2291
2292 static void
2293 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2294 {
2295         if (unlikely(ftrace_disabled))
2296                 return;
2297
2298         mutex_lock(&ftrace_regex_lock);
2299         if (reset)
2300                 ftrace_filter_reset(enable);
2301         if (buf)
2302                 ftrace_match_records(buf, len, enable);
2303         mutex_unlock(&ftrace_regex_lock);
2304 }
2305
2306 /**
2307  * ftrace_set_filter - set a function to filter on in ftrace
2308  * @buf - the string that holds the function filter text.
2309  * @len - the length of the string.
2310  * @reset - non zero to reset all filters before applying this filter.
2311  *
2312  * Filters denote which functions should be enabled when tracing is enabled.
2313  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2314  */
2315 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2316 {
2317         ftrace_set_regex(buf, len, reset, 1);
2318 }
2319
2320 /**
2321  * ftrace_set_notrace - set a function to not trace in ftrace
2322  * @buf - the string that holds the function notrace text.
2323  * @len - the length of the string.
2324  * @reset - non zero to reset all filters before applying this filter.
2325  *
2326  * Notrace Filters denote which functions should not be enabled when tracing
2327  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2328  * for tracing.
2329  */
2330 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2331 {
2332         ftrace_set_regex(buf, len, reset, 0);
2333 }
2334
2335 /*
2336  * command line interface to allow users to set filters on boot up.
2337  */
2338 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
2339 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2340 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2341
2342 static int __init set_ftrace_notrace(char *str)
2343 {
2344         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2345         return 1;
2346 }
2347 __setup("ftrace_notrace=", set_ftrace_notrace);
2348
2349 static int __init set_ftrace_filter(char *str)
2350 {
2351         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2352         return 1;
2353 }
2354 __setup("ftrace_filter=", set_ftrace_filter);
2355
2356 static void __init set_ftrace_early_filter(char *buf, int enable)
2357 {
2358         char *func;
2359
2360         while (buf) {
2361                 func = strsep(&buf, ",");
2362                 ftrace_set_regex(func, strlen(func), 0, enable);
2363         }
2364 }
2365
2366 static void __init set_ftrace_early_filters(void)
2367 {
2368         if (ftrace_filter_buf[0])
2369                 set_ftrace_early_filter(ftrace_filter_buf, 1);
2370         if (ftrace_notrace_buf[0])
2371                 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2372 }
2373
2374 static int
2375 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2376 {
2377         struct seq_file *m = (struct seq_file *)file->private_data;
2378         struct ftrace_iterator *iter;
2379
2380         mutex_lock(&ftrace_regex_lock);
2381         if (file->f_mode & FMODE_READ) {
2382                 iter = m->private;
2383
2384                 seq_release(inode, file);
2385         } else
2386                 iter = file->private_data;
2387
2388         if (iter->buffer_idx) {
2389                 iter->buffer[iter->buffer_idx] = 0;
2390                 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
2391         }
2392
2393         mutex_lock(&ftrace_lock);
2394         if (ftrace_start_up && ftrace_enabled)
2395                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2396         mutex_unlock(&ftrace_lock);
2397
2398         kfree(iter);
2399         mutex_unlock(&ftrace_regex_lock);
2400         return 0;
2401 }
2402
2403 static int
2404 ftrace_filter_release(struct inode *inode, struct file *file)
2405 {
2406         return ftrace_regex_release(inode, file, 1);
2407 }
2408
2409 static int
2410 ftrace_notrace_release(struct inode *inode, struct file *file)
2411 {
2412         return ftrace_regex_release(inode, file, 0);
2413 }
2414
2415 static const struct file_operations ftrace_avail_fops = {
2416         .open = ftrace_avail_open,
2417         .read = seq_read,
2418         .llseek = seq_lseek,
2419         .release = seq_release_private,
2420 };
2421
2422 static const struct file_operations ftrace_failures_fops = {
2423         .open = ftrace_failures_open,
2424         .read = seq_read,
2425         .llseek = seq_lseek,
2426         .release = seq_release_private,
2427 };
2428
2429 static const struct file_operations ftrace_filter_fops = {
2430         .open = ftrace_filter_open,
2431         .read = seq_read,
2432         .write = ftrace_filter_write,
2433         .llseek = ftrace_regex_lseek,
2434         .release = ftrace_filter_release,
2435 };
2436
2437 static const struct file_operations ftrace_notrace_fops = {
2438         .open = ftrace_notrace_open,
2439         .read = seq_read,
2440         .write = ftrace_notrace_write,
2441         .llseek = ftrace_regex_lseek,
2442         .release = ftrace_notrace_release,
2443 };
2444
2445 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2446
2447 static DEFINE_MUTEX(graph_lock);
2448
2449 int ftrace_graph_count;
2450 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2451
2452 static void *
2453 __g_next(struct seq_file *m, loff_t *pos)
2454 {
2455         unsigned long *array = m->private;
2456
2457         if (*pos >= ftrace_graph_count)
2458                 return NULL;
2459         return &array[*pos];
2460 }
2461
2462 static void *
2463 g_next(struct seq_file *m, void *v, loff_t *pos)
2464 {
2465         (*pos)++;
2466         return __g_next(m, pos);
2467 }
2468
2469 static void *g_start(struct seq_file *m, loff_t *pos)
2470 {
2471         mutex_lock(&graph_lock);
2472
2473         /* Nothing, tell g_show to print all functions are enabled */
2474         if (!ftrace_graph_count && !*pos)
2475                 return (void *)1;
2476
2477         return __g_next(m, pos);
2478 }
2479
2480 static void g_stop(struct seq_file *m, void *p)
2481 {
2482         mutex_unlock(&graph_lock);
2483 }
2484
2485 static int g_show(struct seq_file *m, void *v)
2486 {
2487         unsigned long *ptr = v;
2488
2489         if (!ptr)
2490                 return 0;
2491
2492         if (ptr == (unsigned long *)1) {
2493                 seq_printf(m, "#### all functions enabled ####\n");
2494                 return 0;
2495         }
2496
2497         seq_printf(m, "%pf\n", v);
2498
2499         return 0;
2500 }
2501
2502 static struct seq_operations ftrace_graph_seq_ops = {
2503         .start = g_start,
2504         .next = g_next,
2505         .stop = g_stop,
2506         .show = g_show,
2507 };
2508
2509 static int
2510 ftrace_graph_open(struct inode *inode, struct file *file)
2511 {
2512         int ret = 0;
2513
2514         if (unlikely(ftrace_disabled))
2515                 return -ENODEV;
2516
2517         mutex_lock(&graph_lock);
2518         if ((file->f_mode & FMODE_WRITE) &&
2519             (file->f_flags & O_TRUNC)) {
2520                 ftrace_graph_count = 0;
2521                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2522         }
2523
2524         if (file->f_mode & FMODE_READ) {
2525                 ret = seq_open(file, &ftrace_graph_seq_ops);
2526                 if (!ret) {
2527                         struct seq_file *m = file->private_data;
2528                         m->private = ftrace_graph_funcs;
2529                 }
2530         } else
2531                 file->private_data = ftrace_graph_funcs;
2532         mutex_unlock(&graph_lock);
2533
2534         return ret;
2535 }
2536
2537 static int
2538 ftrace_graph_release(struct inode *inode, struct file *file)
2539 {
2540         if (file->f_mode & FMODE_READ)
2541                 seq_release(inode, file);
2542         return 0;
2543 }
2544
2545 static int
2546 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2547 {
2548         struct dyn_ftrace *rec;
2549         struct ftrace_page *pg;
2550         int search_len;
2551         int found = 0;
2552         int type, not;
2553         char *search;
2554         bool exists;
2555         int i;
2556
2557         if (ftrace_disabled)
2558                 return -ENODEV;
2559
2560         /* decode regex */
2561         type = ftrace_setup_glob(buffer, strlen(buffer), &search, &not);
2562         if (not)
2563                 return -EINVAL;
2564
2565         search_len = strlen(search);
2566
2567         mutex_lock(&ftrace_lock);
2568         do_for_each_ftrace_rec(pg, rec) {
2569
2570                 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2571                         break;
2572
2573                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2574                         continue;
2575
2576                 if (ftrace_match_record(rec, search, search_len, type)) {
2577                         /* ensure it is not already in the array */
2578                         exists = false;
2579                         for (i = 0; i < *idx; i++)
2580                                 if (array[i] == rec->ip) {
2581                                         exists = true;
2582                                         break;
2583                                 }
2584                         if (!exists) {
2585                                 array[(*idx)++] = rec->ip;
2586                                 found = 1;
2587                         }
2588                 }
2589         } while_for_each_ftrace_rec();
2590
2591         mutex_unlock(&ftrace_lock);
2592
2593         return found ? 0 : -EINVAL;
2594 }
2595
2596 static ssize_t
2597 ftrace_graph_write(struct file *file, const char __user *ubuf,
2598                    size_t cnt, loff_t *ppos)
2599 {
2600         unsigned char buffer[FTRACE_BUFF_MAX+1];
2601         unsigned long *array;
2602         size_t read = 0;
2603         ssize_t ret;
2604         int index = 0;
2605         char ch;
2606
2607         if (!cnt || cnt < 0)
2608                 return 0;
2609
2610         mutex_lock(&graph_lock);
2611
2612         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2613                 ret = -EBUSY;
2614                 goto out;
2615         }
2616
2617         if (file->f_mode & FMODE_READ) {
2618                 struct seq_file *m = file->private_data;
2619                 array = m->private;
2620         } else
2621                 array = file->private_data;
2622
2623         ret = get_user(ch, ubuf++);
2624         if (ret)
2625                 goto out;
2626         read++;
2627         cnt--;
2628
2629         /* skip white space */
2630         while (cnt && isspace(ch)) {
2631                 ret = get_user(ch, ubuf++);
2632                 if (ret)
2633                         goto out;
2634                 read++;
2635                 cnt--;
2636         }
2637
2638         if (isspace(ch)) {
2639                 *ppos += read;
2640                 ret = read;
2641                 goto out;
2642         }
2643
2644         while (cnt && !isspace(ch)) {
2645                 if (index < FTRACE_BUFF_MAX)
2646                         buffer[index++] = ch;
2647                 else {
2648                         ret = -EINVAL;
2649                         goto out;
2650                 }
2651                 ret = get_user(ch, ubuf++);
2652                 if (ret)
2653                         goto out;
2654                 read++;
2655                 cnt--;
2656         }
2657         buffer[index] = 0;
2658
2659         /* we allow only one expression at a time */
2660         ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2661         if (ret)
2662                 goto out;
2663
2664         file->f_pos += read;
2665
2666         ret = read;
2667  out:
2668         mutex_unlock(&graph_lock);
2669
2670         return ret;
2671 }
2672
2673 static const struct file_operations ftrace_graph_fops = {
2674         .open           = ftrace_graph_open,
2675         .read           = seq_read,
2676         .write          = ftrace_graph_write,
2677         .release        = ftrace_graph_release,
2678 };
2679 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2680
2681 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2682 {
2683
2684         trace_create_file("available_filter_functions", 0444,
2685                         d_tracer, NULL, &ftrace_avail_fops);
2686
2687         trace_create_file("failures", 0444,
2688                         d_tracer, NULL, &ftrace_failures_fops);
2689
2690         trace_create_file("set_ftrace_filter", 0644, d_tracer,
2691                         NULL, &ftrace_filter_fops);
2692
2693         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2694                                     NULL, &ftrace_notrace_fops);
2695
2696 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2697         trace_create_file("set_graph_function", 0444, d_tracer,
2698                                     NULL,
2699                                     &ftrace_graph_fops);
2700 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2701
2702         return 0;
2703 }
2704
2705 static int ftrace_convert_nops(struct module *mod,
2706                                unsigned long *start,
2707                                unsigned long *end)
2708 {
2709         unsigned long *p;
2710         unsigned long addr;
2711         unsigned long flags;
2712
2713         mutex_lock(&ftrace_lock);
2714         p = start;
2715         while (p < end) {
2716                 addr = ftrace_call_adjust(*p++);
2717                 /*
2718                  * Some architecture linkers will pad between
2719                  * the different mcount_loc sections of different
2720                  * object files to satisfy alignments.
2721                  * Skip any NULL pointers.
2722                  */
2723                 if (!addr)
2724                         continue;
2725                 ftrace_record_ip(addr);
2726         }
2727
2728         /* disable interrupts to prevent kstop machine */
2729         local_irq_save(flags);
2730         ftrace_update_code(mod);
2731         local_irq_restore(flags);
2732         mutex_unlock(&ftrace_lock);
2733
2734         return 0;
2735 }
2736
2737 #ifdef CONFIG_MODULES
2738 void ftrace_release(void *start, void *end)
2739 {
2740         struct dyn_ftrace *rec;
2741         struct ftrace_page *pg;
2742         unsigned long s = (unsigned long)start;
2743         unsigned long e = (unsigned long)end;
2744
2745         if (ftrace_disabled || !start || start == end)
2746                 return;
2747
2748         mutex_lock(&ftrace_lock);
2749         do_for_each_ftrace_rec(pg, rec) {
2750                 if ((rec->ip >= s) && (rec->ip < e)) {
2751                         /*
2752                          * rec->ip is changed in ftrace_free_rec()
2753                          * It should not between s and e if record was freed.
2754                          */
2755                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2756                         ftrace_free_rec(rec);
2757                 }
2758         } while_for_each_ftrace_rec();
2759         mutex_unlock(&ftrace_lock);
2760 }
2761
2762 static void ftrace_init_module(struct module *mod,
2763                                unsigned long *start, unsigned long *end)
2764 {
2765         if (ftrace_disabled || start == end)
2766                 return;
2767         ftrace_convert_nops(mod, start, end);
2768 }
2769
2770 static int ftrace_module_notify(struct notifier_block *self,
2771                                 unsigned long val, void *data)
2772 {
2773         struct module *mod = data;
2774
2775         switch (val) {
2776         case MODULE_STATE_COMING:
2777                 ftrace_init_module(mod, mod->ftrace_callsites,
2778                                    mod->ftrace_callsites +
2779                                    mod->num_ftrace_callsites);
2780                 break;
2781         case MODULE_STATE_GOING:
2782                 ftrace_release(mod->ftrace_callsites,
2783                                mod->ftrace_callsites +
2784                                mod->num_ftrace_callsites);
2785                 break;
2786         }
2787
2788         return 0;
2789 }
2790 #else
2791 static int ftrace_module_notify(struct notifier_block *self,
2792                                 unsigned long val, void *data)
2793 {
2794         return 0;
2795 }
2796 #endif /* CONFIG_MODULES */
2797
2798 struct notifier_block ftrace_module_nb = {
2799         .notifier_call = ftrace_module_notify,
2800         .priority = 0,
2801 };
2802
2803 extern unsigned long __start_mcount_loc[];
2804 extern unsigned long __stop_mcount_loc[];
2805
2806 void __init ftrace_init(void)
2807 {
2808         unsigned long count, addr, flags;
2809         int ret;
2810
2811         /* Keep the ftrace pointer to the stub */
2812         addr = (unsigned long)ftrace_stub;
2813
2814         local_irq_save(flags);
2815         ftrace_dyn_arch_init(&addr);
2816         local_irq_restore(flags);
2817
2818         /* ftrace_dyn_arch_init places the return code in addr */
2819         if (addr)
2820                 goto failed;
2821
2822         count = __stop_mcount_loc - __start_mcount_loc;
2823
2824         ret = ftrace_dyn_table_alloc(count);
2825         if (ret)
2826                 goto failed;
2827
2828         last_ftrace_enabled = ftrace_enabled = 1;
2829
2830         ret = ftrace_convert_nops(NULL,
2831                                   __start_mcount_loc,
2832                                   __stop_mcount_loc);
2833
2834         ret = register_module_notifier(&ftrace_module_nb);
2835         if (ret)
2836                 pr_warning("Failed to register trace ftrace module notifier\n");
2837
2838         set_ftrace_early_filters();
2839
2840         return;
2841  failed:
2842         ftrace_disabled = 1;
2843 }
2844
2845 #else
2846
2847 static int __init ftrace_nodyn_init(void)
2848 {
2849         ftrace_enabled = 1;
2850         return 0;
2851 }
2852 device_initcall(ftrace_nodyn_init);
2853
2854 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2855 static inline void ftrace_startup_enable(int command) { }
2856 /* Keep as macros so we do not need to define the commands */
2857 # define ftrace_startup(command)        do { } while (0)
2858 # define ftrace_shutdown(command)       do { } while (0)
2859 # define ftrace_startup_sysctl()        do { } while (0)
2860 # define ftrace_shutdown_sysctl()       do { } while (0)
2861 #endif /* CONFIG_DYNAMIC_FTRACE */
2862
2863 static ssize_t
2864 ftrace_pid_read(struct file *file, char __user *ubuf,
2865                        size_t cnt, loff_t *ppos)
2866 {
2867         char buf[64];
2868         int r;
2869
2870         if (ftrace_pid_trace == ftrace_swapper_pid)
2871                 r = sprintf(buf, "swapper tasks\n");
2872         else if (ftrace_pid_trace)
2873                 r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
2874         else
2875                 r = sprintf(buf, "no pid\n");
2876
2877         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2878 }
2879
2880 static void clear_ftrace_swapper(void)
2881 {
2882         struct task_struct *p;
2883         int cpu;
2884
2885         get_online_cpus();
2886         for_each_online_cpu(cpu) {
2887                 p = idle_task(cpu);
2888                 clear_tsk_trace_trace(p);
2889         }
2890         put_online_cpus();
2891 }
2892
2893 static void set_ftrace_swapper(void)
2894 {
2895         struct task_struct *p;
2896         int cpu;
2897
2898         get_online_cpus();
2899         for_each_online_cpu(cpu) {
2900                 p = idle_task(cpu);
2901                 set_tsk_trace_trace(p);
2902         }
2903         put_online_cpus();
2904 }
2905
2906 static void clear_ftrace_pid(struct pid *pid)
2907 {
2908         struct task_struct *p;
2909
2910         rcu_read_lock();
2911         do_each_pid_task(pid, PIDTYPE_PID, p) {
2912                 clear_tsk_trace_trace(p);
2913         } while_each_pid_task(pid, PIDTYPE_PID, p);
2914         rcu_read_unlock();
2915
2916         put_pid(pid);
2917 }
2918
2919 static void set_ftrace_pid(struct pid *pid)
2920 {
2921         struct task_struct *p;
2922
2923         rcu_read_lock();
2924         do_each_pid_task(pid, PIDTYPE_PID, p) {
2925                 set_tsk_trace_trace(p);
2926         } while_each_pid_task(pid, PIDTYPE_PID, p);
2927         rcu_read_unlock();
2928 }
2929
2930 static void clear_ftrace_pid_task(struct pid **pid)
2931 {
2932         if (*pid == ftrace_swapper_pid)
2933                 clear_ftrace_swapper();
2934         else
2935                 clear_ftrace_pid(*pid);
2936
2937         *pid = NULL;
2938 }
2939
2940 static void set_ftrace_pid_task(struct pid *pid)
2941 {
2942         if (pid == ftrace_swapper_pid)
2943                 set_ftrace_swapper();
2944         else
2945                 set_ftrace_pid(pid);
2946 }
2947
2948 static ssize_t
2949 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2950                    size_t cnt, loff_t *ppos)
2951 {
2952         struct pid *pid;
2953         char buf[64];
2954         long val;
2955         int ret;
2956
2957         if (cnt >= sizeof(buf))
2958                 return -EINVAL;
2959
2960         if (copy_from_user(&buf, ubuf, cnt))
2961                 return -EFAULT;
2962
2963         buf[cnt] = 0;
2964
2965         ret = strict_strtol(buf, 10, &val);
2966         if (ret < 0)
2967                 return ret;
2968
2969         mutex_lock(&ftrace_lock);
2970         if (val < 0) {
2971                 /* disable pid tracing */
2972                 if (!ftrace_pid_trace)
2973                         goto out;
2974
2975                 clear_ftrace_pid_task(&ftrace_pid_trace);
2976
2977         } else {
2978                 /* swapper task is special */
2979                 if (!val) {
2980                         pid = ftrace_swapper_pid;
2981                         if (pid == ftrace_pid_trace)
2982                                 goto out;
2983                 } else {
2984                         pid = find_get_pid(val);
2985
2986                         if (pid == ftrace_pid_trace) {
2987                                 put_pid(pid);
2988                                 goto out;
2989                         }
2990                 }
2991
2992                 if (ftrace_pid_trace)
2993                         clear_ftrace_pid_task(&ftrace_pid_trace);
2994
2995                 if (!pid)
2996                         goto out;
2997
2998                 ftrace_pid_trace = pid;
2999
3000                 set_ftrace_pid_task(ftrace_pid_trace);
3001         }
3002
3003         /* update the function call */
3004         ftrace_update_pid_func();
3005         ftrace_startup_enable(0);
3006
3007  out:
3008         mutex_unlock(&ftrace_lock);
3009
3010         return cnt;
3011 }
3012
3013 static const struct file_operations ftrace_pid_fops = {
3014         .read = ftrace_pid_read,
3015         .write = ftrace_pid_write,
3016 };
3017
3018 static __init int ftrace_init_debugfs(void)
3019 {
3020         struct dentry *d_tracer;
3021
3022         d_tracer = tracing_init_dentry();
3023         if (!d_tracer)
3024                 return 0;
3025
3026         ftrace_init_dyn_debugfs(d_tracer);
3027
3028         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3029                             NULL, &ftrace_pid_fops);
3030
3031         ftrace_profile_debugfs(d_tracer);
3032
3033         return 0;
3034 }
3035 fs_initcall(ftrace_init_debugfs);
3036
3037 /**
3038  * ftrace_kill - kill ftrace
3039  *
3040  * This function should be used by panic code. It stops ftrace
3041  * but in a not so nice way. If you need to simply kill ftrace
3042  * from a non-atomic section, use ftrace_kill.
3043  */
3044 void ftrace_kill(void)
3045 {
3046         ftrace_disabled = 1;
3047         ftrace_enabled = 0;
3048         clear_ftrace_function();
3049 }
3050
3051 /**
3052  * register_ftrace_function - register a function for profiling
3053  * @ops - ops structure that holds the function for profiling.
3054  *
3055  * Register a function to be called by all functions in the
3056  * kernel.
3057  *
3058  * Note: @ops->func and all the functions it calls must be labeled
3059  *       with "notrace", otherwise it will go into a
3060  *       recursive loop.
3061  */
3062 int register_ftrace_function(struct ftrace_ops *ops)
3063 {
3064         int ret;
3065
3066         if (unlikely(ftrace_disabled))
3067                 return -1;
3068
3069         mutex_lock(&ftrace_lock);
3070
3071         ret = __register_ftrace_function(ops);
3072         ftrace_startup(0);
3073
3074         mutex_unlock(&ftrace_lock);
3075         return ret;
3076 }
3077
3078 /**
3079  * unregister_ftrace_function - unregister a function for profiling.
3080  * @ops - ops structure that holds the function to unregister
3081  *
3082  * Unregister a function that was added to be called by ftrace profiling.
3083  */
3084 int unregister_ftrace_function(struct ftrace_ops *ops)
3085 {
3086         int ret;
3087
3088         mutex_lock(&ftrace_lock);
3089         ret = __unregister_ftrace_function(ops);
3090         ftrace_shutdown(0);
3091         mutex_unlock(&ftrace_lock);
3092
3093         return ret;
3094 }
3095
3096 int
3097 ftrace_enable_sysctl(struct ctl_table *table, int write,
3098                      struct file *file, void __user *buffer, size_t *lenp,
3099                      loff_t *ppos)
3100 {
3101         int ret;
3102
3103         if (unlikely(ftrace_disabled))
3104                 return -ENODEV;
3105
3106         mutex_lock(&ftrace_lock);
3107
3108         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
3109
3110         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3111                 goto out;
3112
3113         last_ftrace_enabled = !!ftrace_enabled;
3114
3115         if (ftrace_enabled) {
3116
3117                 ftrace_startup_sysctl();
3118
3119                 /* we are starting ftrace again */
3120                 if (ftrace_list != &ftrace_list_end) {
3121                         if (ftrace_list->next == &ftrace_list_end)
3122                                 ftrace_trace_function = ftrace_list->func;
3123                         else
3124                                 ftrace_trace_function = ftrace_list_func;
3125                 }
3126
3127         } else {
3128                 /* stopping ftrace calls (just send to ftrace_stub) */
3129                 ftrace_trace_function = ftrace_stub;
3130
3131                 ftrace_shutdown_sysctl();
3132         }
3133
3134  out:
3135         mutex_unlock(&ftrace_lock);
3136         return ret;
3137 }
3138
3139 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3140
3141 static int ftrace_graph_active;
3142 static struct notifier_block ftrace_suspend_notifier;
3143
3144 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3145 {
3146         return 0;
3147 }
3148
3149 /* The callbacks that hook a function */
3150 trace_func_graph_ret_t ftrace_graph_return =
3151                         (trace_func_graph_ret_t)ftrace_stub;
3152 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3153
3154 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3155 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3156 {
3157         int i;
3158         int ret = 0;
3159         unsigned long flags;
3160         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3161         struct task_struct *g, *t;
3162
3163         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3164                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3165                                         * sizeof(struct ftrace_ret_stack),
3166                                         GFP_KERNEL);
3167                 if (!ret_stack_list[i]) {
3168                         start = 0;
3169                         end = i;
3170                         ret = -ENOMEM;
3171                         goto free;
3172                 }
3173         }
3174
3175         read_lock_irqsave(&tasklist_lock, flags);
3176         do_each_thread(g, t) {
3177                 if (start == end) {
3178                         ret = -EAGAIN;
3179                         goto unlock;
3180                 }
3181
3182                 if (t->ret_stack == NULL) {
3183                         atomic_set(&t->tracing_graph_pause, 0);
3184                         atomic_set(&t->trace_overrun, 0);
3185                         t->curr_ret_stack = -1;
3186                         /* Make sure the tasks see the -1 first: */
3187                         smp_wmb();
3188                         t->ret_stack = ret_stack_list[start++];
3189                 }
3190         } while_each_thread(g, t);
3191
3192 unlock:
3193         read_unlock_irqrestore(&tasklist_lock, flags);
3194 free:
3195         for (i = start; i < end; i++)
3196                 kfree(ret_stack_list[i]);
3197         return ret;
3198 }
3199
3200 static void
3201 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3202                                 struct task_struct *next)
3203 {
3204         unsigned long long timestamp;
3205         int index;
3206
3207         /*
3208          * Does the user want to count the time a function was asleep.
3209          * If so, do not update the time stamps.
3210          */
3211         if (trace_flags & TRACE_ITER_SLEEP_TIME)
3212                 return;
3213
3214         timestamp = trace_clock_local();
3215
3216         prev->ftrace_timestamp = timestamp;
3217
3218         /* only process tasks that we timestamped */
3219         if (!next->ftrace_timestamp)
3220                 return;
3221
3222         /*
3223          * Update all the counters in next to make up for the
3224          * time next was sleeping.
3225          */
3226         timestamp -= next->ftrace_timestamp;
3227
3228         for (index = next->curr_ret_stack; index >= 0; index--)
3229                 next->ret_stack[index].calltime += timestamp;
3230 }
3231
3232 /* Allocate a return stack for each task */
3233 static int start_graph_tracing(void)
3234 {
3235         struct ftrace_ret_stack **ret_stack_list;
3236         int ret, cpu;
3237
3238         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3239                                 sizeof(struct ftrace_ret_stack *),
3240                                 GFP_KERNEL);
3241
3242         if (!ret_stack_list)
3243                 return -ENOMEM;
3244
3245         /* The cpu_boot init_task->ret_stack will never be freed */
3246         for_each_online_cpu(cpu) {
3247                 if (!idle_task(cpu)->ret_stack)
3248                         ftrace_graph_init_task(idle_task(cpu));
3249         }
3250
3251         do {
3252                 ret = alloc_retstack_tasklist(ret_stack_list);
3253         } while (ret == -EAGAIN);
3254
3255         if (!ret) {
3256                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3257                 if (ret)
3258                         pr_info("ftrace_graph: Couldn't activate tracepoint"
3259                                 " probe to kernel_sched_switch\n");
3260         }
3261
3262         kfree(ret_stack_list);
3263         return ret;
3264 }
3265
3266 /*
3267  * Hibernation protection.
3268  * The state of the current task is too much unstable during
3269  * suspend/restore to disk. We want to protect against that.
3270  */
3271 static int
3272 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3273                                                         void *unused)
3274 {
3275         switch (state) {
3276         case PM_HIBERNATION_PREPARE:
3277                 pause_graph_tracing();
3278                 break;
3279
3280         case PM_POST_HIBERNATION:
3281                 unpause_graph_tracing();
3282                 break;
3283         }
3284         return NOTIFY_DONE;
3285 }
3286
3287 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3288                         trace_func_graph_ent_t entryfunc)
3289 {
3290         int ret = 0;
3291
3292         mutex_lock(&ftrace_lock);
3293
3294         /* we currently allow only one tracer registered at a time */
3295         if (ftrace_graph_active) {
3296                 ret = -EBUSY;
3297                 goto out;
3298         }
3299
3300         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3301         register_pm_notifier(&ftrace_suspend_notifier);
3302
3303         ftrace_graph_active++;
3304         ret = start_graph_tracing();
3305         if (ret) {
3306                 ftrace_graph_active--;
3307                 goto out;
3308         }
3309
3310         ftrace_graph_return = retfunc;
3311         ftrace_graph_entry = entryfunc;
3312
3313         ftrace_startup(FTRACE_START_FUNC_RET);
3314
3315 out:
3316         mutex_unlock(&ftrace_lock);
3317         return ret;
3318 }
3319
3320 void unregister_ftrace_graph(void)
3321 {
3322         mutex_lock(&ftrace_lock);
3323
3324         if (unlikely(!ftrace_graph_active))
3325                 goto out;
3326
3327         ftrace_graph_active--;
3328         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3329         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3330         ftrace_graph_entry = ftrace_graph_entry_stub;
3331         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3332         unregister_pm_notifier(&ftrace_suspend_notifier);
3333
3334  out:
3335         mutex_unlock(&ftrace_lock);
3336 }
3337
3338 /* Allocate a return stack for newly created task */
3339 void ftrace_graph_init_task(struct task_struct *t)
3340 {
3341         /* Make sure we do not use the parent ret_stack */
3342         t->ret_stack = NULL;
3343
3344         if (ftrace_graph_active) {
3345                 struct ftrace_ret_stack *ret_stack;
3346
3347                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3348                                 * sizeof(struct ftrace_ret_stack),
3349                                 GFP_KERNEL);
3350                 if (!ret_stack)
3351                         return;
3352                 t->curr_ret_stack = -1;
3353                 atomic_set(&t->tracing_graph_pause, 0);
3354                 atomic_set(&t->trace_overrun, 0);
3355                 t->ftrace_timestamp = 0;
3356                 /* make curr_ret_stack visable before we add the ret_stack */
3357                 smp_wmb();
3358                 t->ret_stack = ret_stack;
3359         }
3360 }
3361
3362 void ftrace_graph_exit_task(struct task_struct *t)
3363 {
3364         struct ftrace_ret_stack *ret_stack = t->ret_stack;
3365
3366         t->ret_stack = NULL;
3367         /* NULL must become visible to IRQs before we free it: */
3368         barrier();
3369
3370         kfree(ret_stack);
3371 }
3372
3373 void ftrace_graph_stop(void)
3374 {
3375         ftrace_stop();
3376 }
3377 #endif
3378