2 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code in the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/ftrace.h>
26 #include <linux/sysctl.h>
27 #include <linux/ctype.h>
28 #include <linux/list.h>
29 #include <linux/hash.h>
30 #include <linux/rcupdate.h>
32 #include <trace/events/sched.h>
34 #include <asm/ftrace.h>
35 #include <asm/setup.h>
37 #include "trace_output.h"
38 #include "trace_stat.h"
40 #define FTRACE_WARN_ON(cond) \
46 #define FTRACE_WARN_ON_ONCE(cond) \
48 if (WARN_ON_ONCE(cond)) \
52 /* hash bits for specific function selection */
53 #define FTRACE_HASH_BITS 7
54 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
56 /* ftrace_enabled is a method to turn ftrace on or off */
57 int ftrace_enabled __read_mostly;
58 static int last_ftrace_enabled;
60 /* Quick disabling of function tracer. */
61 int function_trace_stop;
63 /* List for set_ftrace_pid's pids. */
64 LIST_HEAD(ftrace_pids);
66 struct list_head list;
71 * ftrace_disabled is set when an anomaly is discovered.
72 * ftrace_disabled is much stronger than ftrace_enabled.
74 static int ftrace_disabled __read_mostly;
76 static DEFINE_MUTEX(ftrace_lock);
78 static struct ftrace_ops ftrace_list_end __read_mostly =
83 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
84 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
85 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
86 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
89 * Traverse the ftrace_list, invoking all entries. The reason that we
90 * can use rcu_dereference_raw() is that elements removed from this list
91 * are simply leaked, so there is no need to interact with a grace-period
92 * mechanism. The rcu_dereference_raw() calls are needed to handle
93 * concurrent insertions into the ftrace_list.
95 * Silly Alpha and silly pointer-speculation compiler optimizations!
97 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
99 struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
101 while (op != &ftrace_list_end) {
102 op->func(ip, parent_ip);
103 op = rcu_dereference_raw(op->next); /*see above*/
107 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
109 if (!test_tsk_trace_trace(current))
112 ftrace_pid_function(ip, parent_ip);
115 static void set_ftrace_pid_function(ftrace_func_t func)
117 /* do not set ftrace_pid_function to itself! */
118 if (func != ftrace_pid_func)
119 ftrace_pid_function = func;
123 * clear_ftrace_function - reset the ftrace function
125 * This NULLs the ftrace function and in essence stops
126 * tracing. There may be lag
128 void clear_ftrace_function(void)
130 ftrace_trace_function = ftrace_stub;
131 __ftrace_trace_function = ftrace_stub;
132 ftrace_pid_function = ftrace_stub;
135 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
137 * For those archs that do not test ftrace_trace_stop in their
138 * mcount call site, we need to do it from C.
140 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
142 if (function_trace_stop)
145 __ftrace_trace_function(ip, parent_ip);
149 static int __register_ftrace_function(struct ftrace_ops *ops)
151 ops->next = ftrace_list;
153 * We are entering ops into the ftrace_list but another
154 * CPU might be walking that list. We need to make sure
155 * the ops->next pointer is valid before another CPU sees
156 * the ops pointer included into the ftrace_list.
158 rcu_assign_pointer(ftrace_list, ops);
160 if (ftrace_enabled) {
163 if (ops->next == &ftrace_list_end)
166 func = ftrace_list_func;
168 if (!list_empty(&ftrace_pids)) {
169 set_ftrace_pid_function(func);
170 func = ftrace_pid_func;
174 * For one func, simply call it directly.
175 * For more than one func, call the chain.
177 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
178 ftrace_trace_function = func;
180 __ftrace_trace_function = func;
181 ftrace_trace_function = ftrace_test_stop_func;
188 static int __unregister_ftrace_function(struct ftrace_ops *ops)
190 struct ftrace_ops **p;
193 * If we are removing the last function, then simply point
194 * to the ftrace_stub.
196 if (ftrace_list == ops && ops->next == &ftrace_list_end) {
197 ftrace_trace_function = ftrace_stub;
198 ftrace_list = &ftrace_list_end;
202 for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
211 if (ftrace_enabled) {
212 /* If we only have one func left, then call that directly */
213 if (ftrace_list->next == &ftrace_list_end) {
214 ftrace_func_t func = ftrace_list->func;
216 if (!list_empty(&ftrace_pids)) {
217 set_ftrace_pid_function(func);
218 func = ftrace_pid_func;
220 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
221 ftrace_trace_function = func;
223 __ftrace_trace_function = func;
231 static void ftrace_update_pid_func(void)
235 if (ftrace_trace_function == ftrace_stub)
238 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
239 func = ftrace_trace_function;
241 func = __ftrace_trace_function;
244 if (!list_empty(&ftrace_pids)) {
245 set_ftrace_pid_function(func);
246 func = ftrace_pid_func;
248 if (func == ftrace_pid_func)
249 func = ftrace_pid_function;
252 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
253 ftrace_trace_function = func;
255 __ftrace_trace_function = func;
259 #ifdef CONFIG_FUNCTION_PROFILER
260 struct ftrace_profile {
261 struct hlist_node node;
263 unsigned long counter;
264 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
265 unsigned long long time;
269 struct ftrace_profile_page {
270 struct ftrace_profile_page *next;
272 struct ftrace_profile records[];
275 struct ftrace_profile_stat {
277 struct hlist_head *hash;
278 struct ftrace_profile_page *pages;
279 struct ftrace_profile_page *start;
280 struct tracer_stat stat;
283 #define PROFILE_RECORDS_SIZE \
284 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
286 #define PROFILES_PER_PAGE \
287 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
289 static int ftrace_profile_bits __read_mostly;
290 static int ftrace_profile_enabled __read_mostly;
292 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
293 static DEFINE_MUTEX(ftrace_profile_lock);
295 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
297 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
300 function_stat_next(void *v, int idx)
302 struct ftrace_profile *rec = v;
303 struct ftrace_profile_page *pg;
305 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
311 if ((void *)rec >= (void *)&pg->records[pg->index]) {
315 rec = &pg->records[0];
323 static void *function_stat_start(struct tracer_stat *trace)
325 struct ftrace_profile_stat *stat =
326 container_of(trace, struct ftrace_profile_stat, stat);
328 if (!stat || !stat->start)
331 return function_stat_next(&stat->start->records[0], 0);
334 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
335 /* function graph compares on total time */
336 static int function_stat_cmp(void *p1, void *p2)
338 struct ftrace_profile *a = p1;
339 struct ftrace_profile *b = p2;
341 if (a->time < b->time)
343 if (a->time > b->time)
349 /* not function graph compares against hits */
350 static int function_stat_cmp(void *p1, void *p2)
352 struct ftrace_profile *a = p1;
353 struct ftrace_profile *b = p2;
355 if (a->counter < b->counter)
357 if (a->counter > b->counter)
364 static int function_stat_headers(struct seq_file *m)
366 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
367 seq_printf(m, " Function "
372 seq_printf(m, " Function Hit\n"
378 static int function_stat_show(struct seq_file *m, void *v)
380 struct ftrace_profile *rec = v;
381 char str[KSYM_SYMBOL_LEN];
382 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
383 static DEFINE_MUTEX(mutex);
384 static struct trace_seq s;
385 unsigned long long avg;
388 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
389 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
391 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
394 do_div(avg, rec->counter);
398 trace_print_graph_duration(rec->time, &s);
399 trace_seq_puts(&s, " ");
400 trace_print_graph_duration(avg, &s);
401 trace_print_seq(m, &s);
402 mutex_unlock(&mutex);
409 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
411 struct ftrace_profile_page *pg;
413 pg = stat->pages = stat->start;
416 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
421 memset(stat->hash, 0,
422 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
425 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
427 struct ftrace_profile_page *pg;
432 /* If we already allocated, do nothing */
436 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
440 #ifdef CONFIG_DYNAMIC_FTRACE
441 functions = ftrace_update_tot_cnt;
444 * We do not know the number of functions that exist because
445 * dynamic tracing is what counts them. With past experience
446 * we have around 20K functions. That should be more than enough.
447 * It is highly unlikely we will execute every function in
453 pg = stat->start = stat->pages;
455 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
457 for (i = 0; i < pages; i++) {
458 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
469 unsigned long tmp = (unsigned long)pg;
475 free_page((unsigned long)stat->pages);
482 static int ftrace_profile_init_cpu(int cpu)
484 struct ftrace_profile_stat *stat;
487 stat = &per_cpu(ftrace_profile_stats, cpu);
490 /* If the profile is already created, simply reset it */
491 ftrace_profile_reset(stat);
496 * We are profiling all functions, but usually only a few thousand
497 * functions are hit. We'll make a hash of 1024 items.
499 size = FTRACE_PROFILE_HASH_SIZE;
501 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
506 if (!ftrace_profile_bits) {
509 for (; size; size >>= 1)
510 ftrace_profile_bits++;
513 /* Preallocate the function profiling pages */
514 if (ftrace_profile_pages_init(stat) < 0) {
523 static int ftrace_profile_init(void)
528 for_each_online_cpu(cpu) {
529 ret = ftrace_profile_init_cpu(cpu);
537 /* interrupts must be disabled */
538 static struct ftrace_profile *
539 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
541 struct ftrace_profile *rec;
542 struct hlist_head *hhd;
543 struct hlist_node *n;
546 key = hash_long(ip, ftrace_profile_bits);
547 hhd = &stat->hash[key];
549 if (hlist_empty(hhd))
552 hlist_for_each_entry_rcu(rec, n, hhd, node) {
560 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
561 struct ftrace_profile *rec)
565 key = hash_long(rec->ip, ftrace_profile_bits);
566 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
570 * The memory is already allocated, this simply finds a new record to use.
572 static struct ftrace_profile *
573 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
575 struct ftrace_profile *rec = NULL;
577 /* prevent recursion (from NMIs) */
578 if (atomic_inc_return(&stat->disabled) != 1)
582 * Try to find the function again since an NMI
583 * could have added it
585 rec = ftrace_find_profiled_func(stat, ip);
589 if (stat->pages->index == PROFILES_PER_PAGE) {
590 if (!stat->pages->next)
592 stat->pages = stat->pages->next;
595 rec = &stat->pages->records[stat->pages->index++];
597 ftrace_add_profile(stat, rec);
600 atomic_dec(&stat->disabled);
606 function_profile_call(unsigned long ip, unsigned long parent_ip)
608 struct ftrace_profile_stat *stat;
609 struct ftrace_profile *rec;
612 if (!ftrace_profile_enabled)
615 local_irq_save(flags);
617 stat = &__get_cpu_var(ftrace_profile_stats);
618 if (!stat->hash || !ftrace_profile_enabled)
621 rec = ftrace_find_profiled_func(stat, ip);
623 rec = ftrace_profile_alloc(stat, ip);
630 local_irq_restore(flags);
633 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
634 static int profile_graph_entry(struct ftrace_graph_ent *trace)
636 function_profile_call(trace->func, 0);
640 static void profile_graph_return(struct ftrace_graph_ret *trace)
642 struct ftrace_profile_stat *stat;
643 unsigned long long calltime;
644 struct ftrace_profile *rec;
647 local_irq_save(flags);
648 stat = &__get_cpu_var(ftrace_profile_stats);
649 if (!stat->hash || !ftrace_profile_enabled)
652 calltime = trace->rettime - trace->calltime;
654 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
657 index = trace->depth;
659 /* Append this call time to the parent time to subtract */
661 current->ret_stack[index - 1].subtime += calltime;
663 if (current->ret_stack[index].subtime < calltime)
664 calltime -= current->ret_stack[index].subtime;
669 rec = ftrace_find_profiled_func(stat, trace->func);
671 rec->time += calltime;
674 local_irq_restore(flags);
677 static int register_ftrace_profiler(void)
679 return register_ftrace_graph(&profile_graph_return,
680 &profile_graph_entry);
683 static void unregister_ftrace_profiler(void)
685 unregister_ftrace_graph();
688 static struct ftrace_ops ftrace_profile_ops __read_mostly =
690 .func = function_profile_call,
693 static int register_ftrace_profiler(void)
695 return register_ftrace_function(&ftrace_profile_ops);
698 static void unregister_ftrace_profiler(void)
700 unregister_ftrace_function(&ftrace_profile_ops);
702 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
705 ftrace_profile_write(struct file *filp, const char __user *ubuf,
706 size_t cnt, loff_t *ppos)
709 char buf[64]; /* big enough to hold a number */
712 if (cnt >= sizeof(buf))
715 if (copy_from_user(&buf, ubuf, cnt))
720 ret = strict_strtoul(buf, 10, &val);
726 mutex_lock(&ftrace_profile_lock);
727 if (ftrace_profile_enabled ^ val) {
729 ret = ftrace_profile_init();
735 ret = register_ftrace_profiler();
740 ftrace_profile_enabled = 1;
742 ftrace_profile_enabled = 0;
744 * unregister_ftrace_profiler calls stop_machine
745 * so this acts like an synchronize_sched.
747 unregister_ftrace_profiler();
751 mutex_unlock(&ftrace_profile_lock);
759 ftrace_profile_read(struct file *filp, char __user *ubuf,
760 size_t cnt, loff_t *ppos)
762 char buf[64]; /* big enough to hold a number */
765 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
766 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
769 static const struct file_operations ftrace_profile_fops = {
770 .open = tracing_open_generic,
771 .read = ftrace_profile_read,
772 .write = ftrace_profile_write,
775 /* used to initialize the real stat files */
776 static struct tracer_stat function_stats __initdata = {
778 .stat_start = function_stat_start,
779 .stat_next = function_stat_next,
780 .stat_cmp = function_stat_cmp,
781 .stat_headers = function_stat_headers,
782 .stat_show = function_stat_show
785 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
787 struct ftrace_profile_stat *stat;
788 struct dentry *entry;
793 for_each_possible_cpu(cpu) {
794 stat = &per_cpu(ftrace_profile_stats, cpu);
796 /* allocate enough for function name + cpu number */
797 name = kmalloc(32, GFP_KERNEL);
800 * The files created are permanent, if something happens
801 * we still do not free memory.
804 "Could not allocate stat file for cpu %d\n",
808 stat->stat = function_stats;
809 snprintf(name, 32, "function%d", cpu);
810 stat->stat.name = name;
811 ret = register_stat_tracer(&stat->stat);
814 "Could not register function stat for cpu %d\n",
821 entry = debugfs_create_file("function_profile_enabled", 0644,
822 d_tracer, NULL, &ftrace_profile_fops);
824 pr_warning("Could not create debugfs "
825 "'function_profile_enabled' entry\n");
828 #else /* CONFIG_FUNCTION_PROFILER */
829 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
832 #endif /* CONFIG_FUNCTION_PROFILER */
834 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
836 #ifdef CONFIG_DYNAMIC_FTRACE
838 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
839 # error Dynamic ftrace depends on MCOUNT_RECORD
842 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
844 struct ftrace_func_probe {
845 struct hlist_node node;
846 struct ftrace_probe_ops *ops;
854 FTRACE_ENABLE_CALLS = (1 << 0),
855 FTRACE_DISABLE_CALLS = (1 << 1),
856 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
857 FTRACE_ENABLE_MCOUNT = (1 << 3),
858 FTRACE_DISABLE_MCOUNT = (1 << 4),
859 FTRACE_START_FUNC_RET = (1 << 5),
860 FTRACE_STOP_FUNC_RET = (1 << 6),
863 static int ftrace_filtered;
865 static struct dyn_ftrace *ftrace_new_addrs;
867 static DEFINE_MUTEX(ftrace_regex_lock);
870 struct ftrace_page *next;
872 struct dyn_ftrace records[];
875 #define ENTRIES_PER_PAGE \
876 ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
878 /* estimate from running different kernels */
879 #define NR_TO_INIT 10000
881 static struct ftrace_page *ftrace_pages_start;
882 static struct ftrace_page *ftrace_pages;
884 static struct dyn_ftrace *ftrace_free_records;
887 * This is a double for. Do not use 'break' to break out of the loop,
888 * you must use a goto.
890 #define do_for_each_ftrace_rec(pg, rec) \
891 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
893 for (_____i = 0; _____i < pg->index; _____i++) { \
894 rec = &pg->records[_____i];
896 #define while_for_each_ftrace_rec() \
900 static void ftrace_free_rec(struct dyn_ftrace *rec)
902 rec->freelist = ftrace_free_records;
903 ftrace_free_records = rec;
904 rec->flags |= FTRACE_FL_FREE;
907 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
909 struct dyn_ftrace *rec;
911 /* First check for freed records */
912 if (ftrace_free_records) {
913 rec = ftrace_free_records;
915 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
916 FTRACE_WARN_ON_ONCE(1);
917 ftrace_free_records = NULL;
921 ftrace_free_records = rec->freelist;
922 memset(rec, 0, sizeof(*rec));
926 if (ftrace_pages->index == ENTRIES_PER_PAGE) {
927 if (!ftrace_pages->next) {
928 /* allocate another page */
930 (void *)get_zeroed_page(GFP_KERNEL);
931 if (!ftrace_pages->next)
934 ftrace_pages = ftrace_pages->next;
937 return &ftrace_pages->records[ftrace_pages->index++];
940 static struct dyn_ftrace *
941 ftrace_record_ip(unsigned long ip)
943 struct dyn_ftrace *rec;
948 rec = ftrace_alloc_dyn_node(ip);
953 rec->newlist = ftrace_new_addrs;
954 ftrace_new_addrs = rec;
959 static void print_ip_ins(const char *fmt, unsigned char *p)
963 printk(KERN_CONT "%s", fmt);
965 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
966 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
969 static void ftrace_bug(int failed, unsigned long ip)
973 FTRACE_WARN_ON_ONCE(1);
974 pr_info("ftrace faulted on modifying ");
978 FTRACE_WARN_ON_ONCE(1);
979 pr_info("ftrace failed to modify ");
981 print_ip_ins(" actual: ", (unsigned char *)ip);
982 printk(KERN_CONT "\n");
985 FTRACE_WARN_ON_ONCE(1);
986 pr_info("ftrace faulted on writing ");
990 FTRACE_WARN_ON_ONCE(1);
991 pr_info("ftrace faulted on unknown error ");
997 /* Return 1 if the address range is reserved for ftrace */
998 int ftrace_text_reserved(void *start, void *end)
1000 struct dyn_ftrace *rec;
1001 struct ftrace_page *pg;
1003 do_for_each_ftrace_rec(pg, rec) {
1004 if (rec->ip <= (unsigned long)end &&
1005 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1007 } while_for_each_ftrace_rec();
1013 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1015 unsigned long ftrace_addr;
1016 unsigned long flag = 0UL;
1018 ftrace_addr = (unsigned long)FTRACE_ADDR;
1021 * If this record is not to be traced or we want to disable it,
1024 * If we want to enable it and filtering is off, then enable it.
1026 * If we want to enable it and filtering is on, enable it only if
1029 if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1030 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1031 flag = FTRACE_FL_ENABLED;
1034 /* If the state of this record hasn't changed, then do nothing */
1035 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1039 rec->flags |= FTRACE_FL_ENABLED;
1040 return ftrace_make_call(rec, ftrace_addr);
1043 rec->flags &= ~FTRACE_FL_ENABLED;
1044 return ftrace_make_nop(NULL, rec, ftrace_addr);
1047 static void ftrace_replace_code(int enable)
1049 struct dyn_ftrace *rec;
1050 struct ftrace_page *pg;
1053 do_for_each_ftrace_rec(pg, rec) {
1055 * Skip over free records, records that have
1056 * failed and not converted.
1058 if (rec->flags & FTRACE_FL_FREE ||
1059 rec->flags & FTRACE_FL_FAILED ||
1060 !(rec->flags & FTRACE_FL_CONVERTED))
1063 failed = __ftrace_replace_code(rec, enable);
1065 rec->flags |= FTRACE_FL_FAILED;
1066 ftrace_bug(failed, rec->ip);
1067 /* Stop processing */
1070 } while_for_each_ftrace_rec();
1074 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1081 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1083 ftrace_bug(ret, ip);
1084 rec->flags |= FTRACE_FL_FAILED;
1091 * archs can override this function if they must do something
1092 * before the modifying code is performed.
1094 int __weak ftrace_arch_code_modify_prepare(void)
1100 * archs can override this function if they must do something
1101 * after the modifying code is performed.
1103 int __weak ftrace_arch_code_modify_post_process(void)
1108 static int __ftrace_modify_code(void *data)
1110 int *command = data;
1112 if (*command & FTRACE_ENABLE_CALLS)
1113 ftrace_replace_code(1);
1114 else if (*command & FTRACE_DISABLE_CALLS)
1115 ftrace_replace_code(0);
1117 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1118 ftrace_update_ftrace_func(ftrace_trace_function);
1120 if (*command & FTRACE_START_FUNC_RET)
1121 ftrace_enable_ftrace_graph_caller();
1122 else if (*command & FTRACE_STOP_FUNC_RET)
1123 ftrace_disable_ftrace_graph_caller();
1128 static void ftrace_run_update_code(int command)
1132 ret = ftrace_arch_code_modify_prepare();
1133 FTRACE_WARN_ON(ret);
1137 stop_machine(__ftrace_modify_code, &command, NULL);
1139 ret = ftrace_arch_code_modify_post_process();
1140 FTRACE_WARN_ON(ret);
1143 static ftrace_func_t saved_ftrace_func;
1144 static int ftrace_start_up;
1146 static void ftrace_startup_enable(int command)
1148 if (saved_ftrace_func != ftrace_trace_function) {
1149 saved_ftrace_func = ftrace_trace_function;
1150 command |= FTRACE_UPDATE_TRACE_FUNC;
1153 if (!command || !ftrace_enabled)
1156 ftrace_run_update_code(command);
1159 static void ftrace_startup(int command)
1161 if (unlikely(ftrace_disabled))
1165 command |= FTRACE_ENABLE_CALLS;
1167 ftrace_startup_enable(command);
1170 static void ftrace_shutdown(int command)
1172 if (unlikely(ftrace_disabled))
1177 * Just warn in case of unbalance, no need to kill ftrace, it's not
1178 * critical but the ftrace_call callers may be never nopped again after
1179 * further ftrace uses.
1181 WARN_ON_ONCE(ftrace_start_up < 0);
1183 if (!ftrace_start_up)
1184 command |= FTRACE_DISABLE_CALLS;
1186 if (saved_ftrace_func != ftrace_trace_function) {
1187 saved_ftrace_func = ftrace_trace_function;
1188 command |= FTRACE_UPDATE_TRACE_FUNC;
1191 if (!command || !ftrace_enabled)
1194 ftrace_run_update_code(command);
1197 static void ftrace_startup_sysctl(void)
1199 int command = FTRACE_ENABLE_MCOUNT;
1201 if (unlikely(ftrace_disabled))
1204 /* Force update next time */
1205 saved_ftrace_func = NULL;
1206 /* ftrace_start_up is true if we want ftrace running */
1207 if (ftrace_start_up)
1208 command |= FTRACE_ENABLE_CALLS;
1210 ftrace_run_update_code(command);
1213 static void ftrace_shutdown_sysctl(void)
1215 int command = FTRACE_DISABLE_MCOUNT;
1217 if (unlikely(ftrace_disabled))
1220 /* ftrace_start_up is true if ftrace is running */
1221 if (ftrace_start_up)
1222 command |= FTRACE_DISABLE_CALLS;
1224 ftrace_run_update_code(command);
1227 static cycle_t ftrace_update_time;
1228 static unsigned long ftrace_update_cnt;
1229 unsigned long ftrace_update_tot_cnt;
1231 static int ftrace_update_code(struct module *mod)
1233 struct dyn_ftrace *p;
1234 cycle_t start, stop;
1236 start = ftrace_now(raw_smp_processor_id());
1237 ftrace_update_cnt = 0;
1239 while (ftrace_new_addrs) {
1241 /* If something went wrong, bail without enabling anything */
1242 if (unlikely(ftrace_disabled))
1245 p = ftrace_new_addrs;
1246 ftrace_new_addrs = p->newlist;
1250 * Do the initial record convertion from mcount jump
1251 * to the NOP instructions.
1253 if (!ftrace_code_disable(mod, p)) {
1258 p->flags |= FTRACE_FL_CONVERTED;
1259 ftrace_update_cnt++;
1262 * If the tracing is enabled, go ahead and enable the record.
1264 * The reason not to enable the record immediatelly is the
1265 * inherent check of ftrace_make_nop/ftrace_make_call for
1266 * correct previous instructions. Making first the NOP
1267 * conversion puts the module to the correct state, thus
1268 * passing the ftrace_make_call check.
1270 if (ftrace_start_up) {
1271 int failed = __ftrace_replace_code(p, 1);
1273 ftrace_bug(failed, p->ip);
1279 stop = ftrace_now(raw_smp_processor_id());
1280 ftrace_update_time = stop - start;
1281 ftrace_update_tot_cnt += ftrace_update_cnt;
1286 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1288 struct ftrace_page *pg;
1292 /* allocate a few pages */
1293 ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1294 if (!ftrace_pages_start)
1298 * Allocate a few more pages.
1300 * TODO: have some parser search vmlinux before
1301 * final linking to find all calls to ftrace.
1303 * a) know how many pages to allocate.
1305 * b) set up the table then.
1307 * The dynamic code is still necessary for
1311 pg = ftrace_pages = ftrace_pages_start;
1313 cnt = num_to_init / ENTRIES_PER_PAGE;
1314 pr_info("ftrace: allocating %ld entries in %d pages\n",
1315 num_to_init, cnt + 1);
1317 for (i = 0; i < cnt; i++) {
1318 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1320 /* If we fail, we'll try later anyway */
1331 FTRACE_ITER_FILTER = (1 << 0),
1332 FTRACE_ITER_NOTRACE = (1 << 1),
1333 FTRACE_ITER_FAILURES = (1 << 2),
1334 FTRACE_ITER_PRINTALL = (1 << 3),
1335 FTRACE_ITER_HASH = (1 << 4),
1338 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1340 struct ftrace_iterator {
1341 struct ftrace_page *pg;
1345 struct trace_parser parser;
1349 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1351 struct ftrace_iterator *iter = m->private;
1352 struct hlist_node *hnd = v;
1353 struct hlist_head *hhd;
1355 WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1360 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1363 hhd = &ftrace_func_hash[iter->hidx];
1365 if (hlist_empty(hhd)) {
1384 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1386 struct ftrace_iterator *iter = m->private;
1390 if (!(iter->flags & FTRACE_ITER_HASH))
1393 iter->flags |= FTRACE_ITER_HASH;
1396 for (l = 0; l <= *pos; ) {
1397 p = t_hash_next(m, p, &l);
1404 static int t_hash_show(struct seq_file *m, void *v)
1406 struct ftrace_func_probe *rec;
1407 struct hlist_node *hnd = v;
1409 rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1411 if (rec->ops->print)
1412 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1414 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1417 seq_printf(m, ":%p", rec->data);
1424 t_next(struct seq_file *m, void *v, loff_t *pos)
1426 struct ftrace_iterator *iter = m->private;
1427 struct dyn_ftrace *rec = NULL;
1429 if (iter->flags & FTRACE_ITER_HASH)
1430 return t_hash_next(m, v, pos);
1434 if (iter->flags & FTRACE_ITER_PRINTALL)
1438 if (iter->idx >= iter->pg->index) {
1439 if (iter->pg->next) {
1440 iter->pg = iter->pg->next;
1445 rec = &iter->pg->records[iter->idx++];
1446 if ((rec->flags & FTRACE_FL_FREE) ||
1448 (!(iter->flags & FTRACE_ITER_FAILURES) &&
1449 (rec->flags & FTRACE_FL_FAILED)) ||
1451 ((iter->flags & FTRACE_ITER_FAILURES) &&
1452 !(rec->flags & FTRACE_FL_FAILED)) ||
1454 ((iter->flags & FTRACE_ITER_FILTER) &&
1455 !(rec->flags & FTRACE_FL_FILTER)) ||
1457 ((iter->flags & FTRACE_ITER_NOTRACE) &&
1458 !(rec->flags & FTRACE_FL_NOTRACE))) {
1467 static void *t_start(struct seq_file *m, loff_t *pos)
1469 struct ftrace_iterator *iter = m->private;
1473 mutex_lock(&ftrace_lock);
1475 * For set_ftrace_filter reading, if we have the filter
1476 * off, we can short cut and just print out that all
1477 * functions are enabled.
1479 if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1481 return t_hash_start(m, pos);
1482 iter->flags |= FTRACE_ITER_PRINTALL;
1486 if (iter->flags & FTRACE_ITER_HASH)
1487 return t_hash_start(m, pos);
1489 iter->pg = ftrace_pages_start;
1491 for (l = 0; l <= *pos; ) {
1492 p = t_next(m, p, &l);
1497 if (!p && iter->flags & FTRACE_ITER_FILTER)
1498 return t_hash_start(m, pos);
1503 static void t_stop(struct seq_file *m, void *p)
1505 mutex_unlock(&ftrace_lock);
1508 static int t_show(struct seq_file *m, void *v)
1510 struct ftrace_iterator *iter = m->private;
1511 struct dyn_ftrace *rec = v;
1513 if (iter->flags & FTRACE_ITER_HASH)
1514 return t_hash_show(m, v);
1516 if (iter->flags & FTRACE_ITER_PRINTALL) {
1517 seq_printf(m, "#### all functions enabled ####\n");
1524 seq_printf(m, "%ps\n", (void *)rec->ip);
1529 static const struct seq_operations show_ftrace_seq_ops = {
1537 ftrace_avail_open(struct inode *inode, struct file *file)
1539 struct ftrace_iterator *iter;
1542 if (unlikely(ftrace_disabled))
1545 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1549 iter->pg = ftrace_pages_start;
1551 ret = seq_open(file, &show_ftrace_seq_ops);
1553 struct seq_file *m = file->private_data;
1564 ftrace_failures_open(struct inode *inode, struct file *file)
1568 struct ftrace_iterator *iter;
1570 ret = ftrace_avail_open(inode, file);
1572 m = (struct seq_file *)file->private_data;
1573 iter = (struct ftrace_iterator *)m->private;
1574 iter->flags = FTRACE_ITER_FAILURES;
1581 static void ftrace_filter_reset(int enable)
1583 struct ftrace_page *pg;
1584 struct dyn_ftrace *rec;
1585 unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1587 mutex_lock(&ftrace_lock);
1589 ftrace_filtered = 0;
1590 do_for_each_ftrace_rec(pg, rec) {
1591 if (rec->flags & FTRACE_FL_FAILED)
1593 rec->flags &= ~type;
1594 } while_for_each_ftrace_rec();
1595 mutex_unlock(&ftrace_lock);
1599 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1601 struct ftrace_iterator *iter;
1604 if (unlikely(ftrace_disabled))
1607 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1611 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1616 mutex_lock(&ftrace_regex_lock);
1617 if ((file->f_mode & FMODE_WRITE) &&
1618 (file->f_flags & O_TRUNC))
1619 ftrace_filter_reset(enable);
1621 if (file->f_mode & FMODE_READ) {
1622 iter->pg = ftrace_pages_start;
1623 iter->flags = enable ? FTRACE_ITER_FILTER :
1624 FTRACE_ITER_NOTRACE;
1626 ret = seq_open(file, &show_ftrace_seq_ops);
1628 struct seq_file *m = file->private_data;
1631 trace_parser_put(&iter->parser);
1635 file->private_data = iter;
1636 mutex_unlock(&ftrace_regex_lock);
1642 ftrace_filter_open(struct inode *inode, struct file *file)
1644 return ftrace_regex_open(inode, file, 1);
1648 ftrace_notrace_open(struct inode *inode, struct file *file)
1650 return ftrace_regex_open(inode, file, 0);
1654 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1658 if (file->f_mode & FMODE_READ)
1659 ret = seq_lseek(file, offset, origin);
1661 file->f_pos = ret = 1;
1666 static int ftrace_match(char *str, char *regex, int len, int type)
1673 if (strcmp(str, regex) == 0)
1676 case MATCH_FRONT_ONLY:
1677 if (strncmp(str, regex, len) == 0)
1680 case MATCH_MIDDLE_ONLY:
1681 if (strstr(str, regex))
1684 case MATCH_END_ONLY:
1686 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1695 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1697 char str[KSYM_SYMBOL_LEN];
1699 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1700 return ftrace_match(str, regex, len, type);
1703 static int ftrace_match_records(char *buff, int len, int enable)
1705 unsigned int search_len;
1706 struct ftrace_page *pg;
1707 struct dyn_ftrace *rec;
1714 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1715 type = filter_parse_regex(buff, len, &search, ¬);
1717 search_len = strlen(search);
1719 mutex_lock(&ftrace_lock);
1720 do_for_each_ftrace_rec(pg, rec) {
1722 if (rec->flags & FTRACE_FL_FAILED)
1725 if (ftrace_match_record(rec, search, search_len, type)) {
1727 rec->flags &= ~flag;
1733 * Only enable filtering if we have a function that
1736 if (enable && (rec->flags & FTRACE_FL_FILTER))
1737 ftrace_filtered = 1;
1738 } while_for_each_ftrace_rec();
1739 mutex_unlock(&ftrace_lock);
1745 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1746 char *regex, int len, int type)
1748 char str[KSYM_SYMBOL_LEN];
1751 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1753 if (!modname || strcmp(modname, mod))
1756 /* blank search means to match all funcs in the mod */
1758 return ftrace_match(str, regex, len, type);
1763 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1765 unsigned search_len = 0;
1766 struct ftrace_page *pg;
1767 struct dyn_ftrace *rec;
1768 int type = MATCH_FULL;
1769 char *search = buff;
1774 flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1776 /* blank or '*' mean the same */
1777 if (strcmp(buff, "*") == 0)
1780 /* handle the case of 'dont filter this module' */
1781 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1787 type = filter_parse_regex(buff, strlen(buff), &search, ¬);
1788 search_len = strlen(search);
1791 mutex_lock(&ftrace_lock);
1792 do_for_each_ftrace_rec(pg, rec) {
1794 if (rec->flags & FTRACE_FL_FAILED)
1797 if (ftrace_match_module_record(rec, mod,
1798 search, search_len, type)) {
1800 rec->flags &= ~flag;
1805 if (enable && (rec->flags & FTRACE_FL_FILTER))
1806 ftrace_filtered = 1;
1808 } while_for_each_ftrace_rec();
1809 mutex_unlock(&ftrace_lock);
1815 * We register the module command as a template to show others how
1816 * to register the a command as well.
1820 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1825 * cmd == 'mod' because we only registered this func
1826 * for the 'mod' ftrace_func_command.
1827 * But if you register one func with multiple commands,
1828 * you can tell which command was used by the cmd
1832 /* we must have a module name */
1836 mod = strsep(¶m, ":");
1840 if (ftrace_match_module_records(func, mod, enable))
1845 static struct ftrace_func_command ftrace_mod_cmd = {
1847 .func = ftrace_mod_callback,
1850 static int __init ftrace_mod_cmd_init(void)
1852 return register_ftrace_command(&ftrace_mod_cmd);
1854 device_initcall(ftrace_mod_cmd_init);
1857 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1859 struct ftrace_func_probe *entry;
1860 struct hlist_head *hhd;
1861 struct hlist_node *n;
1865 key = hash_long(ip, FTRACE_HASH_BITS);
1867 hhd = &ftrace_func_hash[key];
1869 if (hlist_empty(hhd))
1873 * Disable preemption for these calls to prevent a RCU grace
1874 * period. This syncs the hash iteration and freeing of items
1875 * on the hash. rcu_read_lock is too dangerous here.
1877 resched = ftrace_preempt_disable();
1878 hlist_for_each_entry_rcu(entry, n, hhd, node) {
1879 if (entry->ip == ip)
1880 entry->ops->func(ip, parent_ip, &entry->data);
1882 ftrace_preempt_enable(resched);
1885 static struct ftrace_ops trace_probe_ops __read_mostly =
1887 .func = function_trace_probe_call,
1890 static int ftrace_probe_registered;
1892 static void __enable_ftrace_function_probe(void)
1896 if (ftrace_probe_registered)
1899 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1900 struct hlist_head *hhd = &ftrace_func_hash[i];
1904 /* Nothing registered? */
1905 if (i == FTRACE_FUNC_HASHSIZE)
1908 __register_ftrace_function(&trace_probe_ops);
1910 ftrace_probe_registered = 1;
1913 static void __disable_ftrace_function_probe(void)
1917 if (!ftrace_probe_registered)
1920 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1921 struct hlist_head *hhd = &ftrace_func_hash[i];
1926 /* no more funcs left */
1927 __unregister_ftrace_function(&trace_probe_ops);
1929 ftrace_probe_registered = 0;
1933 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1935 struct ftrace_func_probe *entry =
1936 container_of(rhp, struct ftrace_func_probe, rcu);
1938 if (entry->ops->free)
1939 entry->ops->free(&entry->data);
1945 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1948 struct ftrace_func_probe *entry;
1949 struct ftrace_page *pg;
1950 struct dyn_ftrace *rec;
1956 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
1957 len = strlen(search);
1959 /* we do not support '!' for function probes */
1963 mutex_lock(&ftrace_lock);
1964 do_for_each_ftrace_rec(pg, rec) {
1966 if (rec->flags & FTRACE_FL_FAILED)
1969 if (!ftrace_match_record(rec, search, len, type))
1972 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1974 /* If we did not process any, then return error */
1985 * The caller might want to do something special
1986 * for each function we find. We call the callback
1987 * to give the caller an opportunity to do so.
1989 if (ops->callback) {
1990 if (ops->callback(rec->ip, &entry->data) < 0) {
1991 /* caller does not like this func */
1998 entry->ip = rec->ip;
2000 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2001 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2003 } while_for_each_ftrace_rec();
2004 __enable_ftrace_function_probe();
2007 mutex_unlock(&ftrace_lock);
2013 PROBE_TEST_FUNC = 1,
2018 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2019 void *data, int flags)
2021 struct ftrace_func_probe *entry;
2022 struct hlist_node *n, *tmp;
2023 char str[KSYM_SYMBOL_LEN];
2024 int type = MATCH_FULL;
2028 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2033 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
2034 len = strlen(search);
2036 /* we do not support '!' for function probes */
2041 mutex_lock(&ftrace_lock);
2042 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2043 struct hlist_head *hhd = &ftrace_func_hash[i];
2045 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2047 /* break up if statements for readability */
2048 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2051 if ((flags & PROBE_TEST_DATA) && entry->data != data)
2054 /* do this last, since it is the most expensive */
2056 kallsyms_lookup(entry->ip, NULL, NULL,
2058 if (!ftrace_match(str, glob, len, type))
2062 hlist_del(&entry->node);
2063 call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2066 __disable_ftrace_function_probe();
2067 mutex_unlock(&ftrace_lock);
2071 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2074 __unregister_ftrace_function_probe(glob, ops, data,
2075 PROBE_TEST_FUNC | PROBE_TEST_DATA);
2079 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2081 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2084 void unregister_ftrace_function_probe_all(char *glob)
2086 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2089 static LIST_HEAD(ftrace_commands);
2090 static DEFINE_MUTEX(ftrace_cmd_mutex);
2092 int register_ftrace_command(struct ftrace_func_command *cmd)
2094 struct ftrace_func_command *p;
2097 mutex_lock(&ftrace_cmd_mutex);
2098 list_for_each_entry(p, &ftrace_commands, list) {
2099 if (strcmp(cmd->name, p->name) == 0) {
2104 list_add(&cmd->list, &ftrace_commands);
2106 mutex_unlock(&ftrace_cmd_mutex);
2111 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2113 struct ftrace_func_command *p, *n;
2116 mutex_lock(&ftrace_cmd_mutex);
2117 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2118 if (strcmp(cmd->name, p->name) == 0) {
2120 list_del_init(&p->list);
2125 mutex_unlock(&ftrace_cmd_mutex);
2130 static int ftrace_process_regex(char *buff, int len, int enable)
2132 char *func, *command, *next = buff;
2133 struct ftrace_func_command *p;
2136 func = strsep(&next, ":");
2139 if (ftrace_match_records(func, len, enable))
2146 command = strsep(&next, ":");
2148 mutex_lock(&ftrace_cmd_mutex);
2149 list_for_each_entry(p, &ftrace_commands, list) {
2150 if (strcmp(p->name, command) == 0) {
2151 ret = p->func(func, command, next, enable);
2156 mutex_unlock(&ftrace_cmd_mutex);
2162 ftrace_regex_write(struct file *file, const char __user *ubuf,
2163 size_t cnt, loff_t *ppos, int enable)
2165 struct ftrace_iterator *iter;
2166 struct trace_parser *parser;
2172 mutex_lock(&ftrace_regex_lock);
2174 if (file->f_mode & FMODE_READ) {
2175 struct seq_file *m = file->private_data;
2178 iter = file->private_data;
2180 parser = &iter->parser;
2181 read = trace_get_user(parser, ubuf, cnt, ppos);
2183 if (read >= 0 && trace_parser_loaded(parser) &&
2184 !trace_parser_cont(parser)) {
2185 ret = ftrace_process_regex(parser->buffer,
2186 parser->idx, enable);
2187 trace_parser_clear(parser);
2194 mutex_unlock(&ftrace_regex_lock);
2200 ftrace_filter_write(struct file *file, const char __user *ubuf,
2201 size_t cnt, loff_t *ppos)
2203 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2207 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2208 size_t cnt, loff_t *ppos)
2210 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2214 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2216 if (unlikely(ftrace_disabled))
2219 mutex_lock(&ftrace_regex_lock);
2221 ftrace_filter_reset(enable);
2223 ftrace_match_records(buf, len, enable);
2224 mutex_unlock(&ftrace_regex_lock);
2228 * ftrace_set_filter - set a function to filter on in ftrace
2229 * @buf - the string that holds the function filter text.
2230 * @len - the length of the string.
2231 * @reset - non zero to reset all filters before applying this filter.
2233 * Filters denote which functions should be enabled when tracing is enabled.
2234 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2236 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2238 ftrace_set_regex(buf, len, reset, 1);
2242 * ftrace_set_notrace - set a function to not trace in ftrace
2243 * @buf - the string that holds the function notrace text.
2244 * @len - the length of the string.
2245 * @reset - non zero to reset all filters before applying this filter.
2247 * Notrace Filters denote which functions should not be enabled when tracing
2248 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2251 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2253 ftrace_set_regex(buf, len, reset, 0);
2257 * command line interface to allow users to set filters on boot up.
2259 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
2260 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2261 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2263 static int __init set_ftrace_notrace(char *str)
2265 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2268 __setup("ftrace_notrace=", set_ftrace_notrace);
2270 static int __init set_ftrace_filter(char *str)
2272 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2275 __setup("ftrace_filter=", set_ftrace_filter);
2277 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2278 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2279 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
2281 static int __init set_graph_function(char *str)
2283 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2286 __setup("ftrace_graph_filter=", set_graph_function);
2288 static void __init set_ftrace_early_graph(char *buf)
2294 func = strsep(&buf, ",");
2295 /* we allow only one expression at a time */
2296 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2299 printk(KERN_DEBUG "ftrace: function %s not "
2300 "traceable\n", func);
2303 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2305 static void __init set_ftrace_early_filter(char *buf, int enable)
2310 func = strsep(&buf, ",");
2311 ftrace_set_regex(func, strlen(func), 0, enable);
2315 static void __init set_ftrace_early_filters(void)
2317 if (ftrace_filter_buf[0])
2318 set_ftrace_early_filter(ftrace_filter_buf, 1);
2319 if (ftrace_notrace_buf[0])
2320 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2321 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2322 if (ftrace_graph_buf[0])
2323 set_ftrace_early_graph(ftrace_graph_buf);
2324 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2328 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2330 struct seq_file *m = (struct seq_file *)file->private_data;
2331 struct ftrace_iterator *iter;
2332 struct trace_parser *parser;
2334 mutex_lock(&ftrace_regex_lock);
2335 if (file->f_mode & FMODE_READ) {
2338 seq_release(inode, file);
2340 iter = file->private_data;
2342 parser = &iter->parser;
2343 if (trace_parser_loaded(parser)) {
2344 parser->buffer[parser->idx] = 0;
2345 ftrace_match_records(parser->buffer, parser->idx, enable);
2348 mutex_lock(&ftrace_lock);
2349 if (ftrace_start_up && ftrace_enabled)
2350 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2351 mutex_unlock(&ftrace_lock);
2353 trace_parser_put(parser);
2356 mutex_unlock(&ftrace_regex_lock);
2361 ftrace_filter_release(struct inode *inode, struct file *file)
2363 return ftrace_regex_release(inode, file, 1);
2367 ftrace_notrace_release(struct inode *inode, struct file *file)
2369 return ftrace_regex_release(inode, file, 0);
2372 static const struct file_operations ftrace_avail_fops = {
2373 .open = ftrace_avail_open,
2375 .llseek = seq_lseek,
2376 .release = seq_release_private,
2379 static const struct file_operations ftrace_failures_fops = {
2380 .open = ftrace_failures_open,
2382 .llseek = seq_lseek,
2383 .release = seq_release_private,
2386 static const struct file_operations ftrace_filter_fops = {
2387 .open = ftrace_filter_open,
2389 .write = ftrace_filter_write,
2390 .llseek = ftrace_regex_lseek,
2391 .release = ftrace_filter_release,
2394 static const struct file_operations ftrace_notrace_fops = {
2395 .open = ftrace_notrace_open,
2397 .write = ftrace_notrace_write,
2398 .llseek = ftrace_regex_lseek,
2399 .release = ftrace_notrace_release,
2402 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2404 static DEFINE_MUTEX(graph_lock);
2406 int ftrace_graph_count;
2407 int ftrace_graph_filter_enabled;
2408 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2411 __g_next(struct seq_file *m, loff_t *pos)
2413 if (*pos >= ftrace_graph_count)
2415 return &ftrace_graph_funcs[*pos];
2419 g_next(struct seq_file *m, void *v, loff_t *pos)
2422 return __g_next(m, pos);
2425 static void *g_start(struct seq_file *m, loff_t *pos)
2427 mutex_lock(&graph_lock);
2429 /* Nothing, tell g_show to print all functions are enabled */
2430 if (!ftrace_graph_filter_enabled && !*pos)
2433 return __g_next(m, pos);
2436 static void g_stop(struct seq_file *m, void *p)
2438 mutex_unlock(&graph_lock);
2441 static int g_show(struct seq_file *m, void *v)
2443 unsigned long *ptr = v;
2448 if (ptr == (unsigned long *)1) {
2449 seq_printf(m, "#### all functions enabled ####\n");
2453 seq_printf(m, "%ps\n", (void *)*ptr);
2458 static const struct seq_operations ftrace_graph_seq_ops = {
2466 ftrace_graph_open(struct inode *inode, struct file *file)
2470 if (unlikely(ftrace_disabled))
2473 mutex_lock(&graph_lock);
2474 if ((file->f_mode & FMODE_WRITE) &&
2475 (file->f_flags & O_TRUNC)) {
2476 ftrace_graph_filter_enabled = 0;
2477 ftrace_graph_count = 0;
2478 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2480 mutex_unlock(&graph_lock);
2482 if (file->f_mode & FMODE_READ)
2483 ret = seq_open(file, &ftrace_graph_seq_ops);
2489 ftrace_graph_release(struct inode *inode, struct file *file)
2491 if (file->f_mode & FMODE_READ)
2492 seq_release(inode, file);
2497 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2499 struct dyn_ftrace *rec;
2500 struct ftrace_page *pg;
2508 if (ftrace_disabled)
2512 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
2513 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
2516 search_len = strlen(search);
2518 mutex_lock(&ftrace_lock);
2519 do_for_each_ftrace_rec(pg, rec) {
2521 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2524 if (ftrace_match_record(rec, search, search_len, type)) {
2525 /* if it is in the array */
2527 for (i = 0; i < *idx; i++) {
2528 if (array[i] == rec->ip) {
2537 array[(*idx)++] = rec->ip;
2538 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2543 array[i] = array[--(*idx)];
2549 } while_for_each_ftrace_rec();
2551 mutex_unlock(&ftrace_lock);
2556 ftrace_graph_filter_enabled = 1;
2561 ftrace_graph_write(struct file *file, const char __user *ubuf,
2562 size_t cnt, loff_t *ppos)
2564 struct trace_parser parser;
2570 mutex_lock(&graph_lock);
2572 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2577 read = trace_get_user(&parser, ubuf, cnt, ppos);
2579 if (read >= 0 && trace_parser_loaded((&parser))) {
2580 parser.buffer[parser.idx] = 0;
2582 /* we allow only one expression at a time */
2583 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2592 trace_parser_put(&parser);
2594 mutex_unlock(&graph_lock);
2599 static const struct file_operations ftrace_graph_fops = {
2600 .open = ftrace_graph_open,
2602 .write = ftrace_graph_write,
2603 .release = ftrace_graph_release,
2605 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2607 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2610 trace_create_file("available_filter_functions", 0444,
2611 d_tracer, NULL, &ftrace_avail_fops);
2613 trace_create_file("failures", 0444,
2614 d_tracer, NULL, &ftrace_failures_fops);
2616 trace_create_file("set_ftrace_filter", 0644, d_tracer,
2617 NULL, &ftrace_filter_fops);
2619 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2620 NULL, &ftrace_notrace_fops);
2622 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2623 trace_create_file("set_graph_function", 0444, d_tracer,
2625 &ftrace_graph_fops);
2626 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2631 static int ftrace_process_locs(struct module *mod,
2632 unsigned long *start,
2637 unsigned long flags;
2639 mutex_lock(&ftrace_lock);
2642 addr = ftrace_call_adjust(*p++);
2644 * Some architecture linkers will pad between
2645 * the different mcount_loc sections of different
2646 * object files to satisfy alignments.
2647 * Skip any NULL pointers.
2651 ftrace_record_ip(addr);
2654 /* disable interrupts to prevent kstop machine */
2655 local_irq_save(flags);
2656 ftrace_update_code(mod);
2657 local_irq_restore(flags);
2658 mutex_unlock(&ftrace_lock);
2663 #ifdef CONFIG_MODULES
2664 void ftrace_release_mod(struct module *mod)
2666 struct dyn_ftrace *rec;
2667 struct ftrace_page *pg;
2669 if (ftrace_disabled)
2672 mutex_lock(&ftrace_lock);
2673 do_for_each_ftrace_rec(pg, rec) {
2674 if (within_module_core(rec->ip, mod)) {
2676 * rec->ip is changed in ftrace_free_rec()
2677 * It should not between s and e if record was freed.
2679 FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2680 ftrace_free_rec(rec);
2682 } while_for_each_ftrace_rec();
2683 mutex_unlock(&ftrace_lock);
2686 static void ftrace_init_module(struct module *mod,
2687 unsigned long *start, unsigned long *end)
2689 if (ftrace_disabled || start == end)
2691 ftrace_process_locs(mod, start, end);
2694 static int ftrace_module_notify(struct notifier_block *self,
2695 unsigned long val, void *data)
2697 struct module *mod = data;
2700 case MODULE_STATE_COMING:
2701 ftrace_init_module(mod, mod->ftrace_callsites,
2702 mod->ftrace_callsites +
2703 mod->num_ftrace_callsites);
2705 case MODULE_STATE_GOING:
2706 ftrace_release_mod(mod);
2713 static int ftrace_module_notify(struct notifier_block *self,
2714 unsigned long val, void *data)
2718 #endif /* CONFIG_MODULES */
2720 struct notifier_block ftrace_module_nb = {
2721 .notifier_call = ftrace_module_notify,
2725 extern unsigned long __start_mcount_loc[];
2726 extern unsigned long __stop_mcount_loc[];
2728 void __init ftrace_init(void)
2730 unsigned long count, addr, flags;
2733 /* Keep the ftrace pointer to the stub */
2734 addr = (unsigned long)ftrace_stub;
2736 local_irq_save(flags);
2737 ftrace_dyn_arch_init(&addr);
2738 local_irq_restore(flags);
2740 /* ftrace_dyn_arch_init places the return code in addr */
2744 count = __stop_mcount_loc - __start_mcount_loc;
2746 ret = ftrace_dyn_table_alloc(count);
2750 last_ftrace_enabled = ftrace_enabled = 1;
2752 ret = ftrace_process_locs(NULL,
2756 ret = register_module_notifier(&ftrace_module_nb);
2758 pr_warning("Failed to register trace ftrace module notifier\n");
2760 set_ftrace_early_filters();
2764 ftrace_disabled = 1;
2769 static int __init ftrace_nodyn_init(void)
2774 device_initcall(ftrace_nodyn_init);
2776 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2777 static inline void ftrace_startup_enable(int command) { }
2778 /* Keep as macros so we do not need to define the commands */
2779 # define ftrace_startup(command) do { } while (0)
2780 # define ftrace_shutdown(command) do { } while (0)
2781 # define ftrace_startup_sysctl() do { } while (0)
2782 # define ftrace_shutdown_sysctl() do { } while (0)
2783 #endif /* CONFIG_DYNAMIC_FTRACE */
2785 static void clear_ftrace_swapper(void)
2787 struct task_struct *p;
2791 for_each_online_cpu(cpu) {
2793 clear_tsk_trace_trace(p);
2798 static void set_ftrace_swapper(void)
2800 struct task_struct *p;
2804 for_each_online_cpu(cpu) {
2806 set_tsk_trace_trace(p);
2811 static void clear_ftrace_pid(struct pid *pid)
2813 struct task_struct *p;
2816 do_each_pid_task(pid, PIDTYPE_PID, p) {
2817 clear_tsk_trace_trace(p);
2818 } while_each_pid_task(pid, PIDTYPE_PID, p);
2824 static void set_ftrace_pid(struct pid *pid)
2826 struct task_struct *p;
2829 do_each_pid_task(pid, PIDTYPE_PID, p) {
2830 set_tsk_trace_trace(p);
2831 } while_each_pid_task(pid, PIDTYPE_PID, p);
2835 static void clear_ftrace_pid_task(struct pid *pid)
2837 if (pid == ftrace_swapper_pid)
2838 clear_ftrace_swapper();
2840 clear_ftrace_pid(pid);
2843 static void set_ftrace_pid_task(struct pid *pid)
2845 if (pid == ftrace_swapper_pid)
2846 set_ftrace_swapper();
2848 set_ftrace_pid(pid);
2851 static int ftrace_pid_add(int p)
2854 struct ftrace_pid *fpid;
2857 mutex_lock(&ftrace_lock);
2860 pid = ftrace_swapper_pid;
2862 pid = find_get_pid(p);
2869 list_for_each_entry(fpid, &ftrace_pids, list)
2870 if (fpid->pid == pid)
2875 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2879 list_add(&fpid->list, &ftrace_pids);
2882 set_ftrace_pid_task(pid);
2884 ftrace_update_pid_func();
2885 ftrace_startup_enable(0);
2887 mutex_unlock(&ftrace_lock);
2891 if (pid != ftrace_swapper_pid)
2895 mutex_unlock(&ftrace_lock);
2899 static void ftrace_pid_reset(void)
2901 struct ftrace_pid *fpid, *safe;
2903 mutex_lock(&ftrace_lock);
2904 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2905 struct pid *pid = fpid->pid;
2907 clear_ftrace_pid_task(pid);
2909 list_del(&fpid->list);
2913 ftrace_update_pid_func();
2914 ftrace_startup_enable(0);
2916 mutex_unlock(&ftrace_lock);
2919 static void *fpid_start(struct seq_file *m, loff_t *pos)
2921 mutex_lock(&ftrace_lock);
2923 if (list_empty(&ftrace_pids) && (!*pos))
2926 return seq_list_start(&ftrace_pids, *pos);
2929 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
2934 return seq_list_next(v, &ftrace_pids, pos);
2937 static void fpid_stop(struct seq_file *m, void *p)
2939 mutex_unlock(&ftrace_lock);
2942 static int fpid_show(struct seq_file *m, void *v)
2944 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
2946 if (v == (void *)1) {
2947 seq_printf(m, "no pid\n");
2951 if (fpid->pid == ftrace_swapper_pid)
2952 seq_printf(m, "swapper tasks\n");
2954 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
2959 static const struct seq_operations ftrace_pid_sops = {
2960 .start = fpid_start,
2967 ftrace_pid_open(struct inode *inode, struct file *file)
2971 if ((file->f_mode & FMODE_WRITE) &&
2972 (file->f_flags & O_TRUNC))
2975 if (file->f_mode & FMODE_READ)
2976 ret = seq_open(file, &ftrace_pid_sops);
2982 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2983 size_t cnt, loff_t *ppos)
2989 if (cnt >= sizeof(buf))
2992 if (copy_from_user(&buf, ubuf, cnt))
2998 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
2999 * to clean the filter quietly.
3001 tmp = strstrip(buf);
3002 if (strlen(tmp) == 0)
3005 ret = strict_strtol(tmp, 10, &val);
3009 ret = ftrace_pid_add(val);
3011 return ret ? ret : cnt;
3015 ftrace_pid_release(struct inode *inode, struct file *file)
3017 if (file->f_mode & FMODE_READ)
3018 seq_release(inode, file);
3023 static const struct file_operations ftrace_pid_fops = {
3024 .open = ftrace_pid_open,
3025 .write = ftrace_pid_write,
3027 .llseek = seq_lseek,
3028 .release = ftrace_pid_release,
3031 static __init int ftrace_init_debugfs(void)
3033 struct dentry *d_tracer;
3035 d_tracer = tracing_init_dentry();
3039 ftrace_init_dyn_debugfs(d_tracer);
3041 trace_create_file("set_ftrace_pid", 0644, d_tracer,
3042 NULL, &ftrace_pid_fops);
3044 ftrace_profile_debugfs(d_tracer);
3048 fs_initcall(ftrace_init_debugfs);
3051 * ftrace_kill - kill ftrace
3053 * This function should be used by panic code. It stops ftrace
3054 * but in a not so nice way. If you need to simply kill ftrace
3055 * from a non-atomic section, use ftrace_kill.
3057 void ftrace_kill(void)
3059 ftrace_disabled = 1;
3061 clear_ftrace_function();
3065 * register_ftrace_function - register a function for profiling
3066 * @ops - ops structure that holds the function for profiling.
3068 * Register a function to be called by all functions in the
3071 * Note: @ops->func and all the functions it calls must be labeled
3072 * with "notrace", otherwise it will go into a
3075 int register_ftrace_function(struct ftrace_ops *ops)
3079 if (unlikely(ftrace_disabled))
3082 mutex_lock(&ftrace_lock);
3084 ret = __register_ftrace_function(ops);
3087 mutex_unlock(&ftrace_lock);
3092 * unregister_ftrace_function - unregister a function for profiling.
3093 * @ops - ops structure that holds the function to unregister
3095 * Unregister a function that was added to be called by ftrace profiling.
3097 int unregister_ftrace_function(struct ftrace_ops *ops)
3101 mutex_lock(&ftrace_lock);
3102 ret = __unregister_ftrace_function(ops);
3104 mutex_unlock(&ftrace_lock);
3110 ftrace_enable_sysctl(struct ctl_table *table, int write,
3111 void __user *buffer, size_t *lenp,
3116 if (unlikely(ftrace_disabled))
3119 mutex_lock(&ftrace_lock);
3121 ret = proc_dointvec(table, write, buffer, lenp, ppos);
3123 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3126 last_ftrace_enabled = !!ftrace_enabled;
3128 if (ftrace_enabled) {
3130 ftrace_startup_sysctl();
3132 /* we are starting ftrace again */
3133 if (ftrace_list != &ftrace_list_end) {
3134 if (ftrace_list->next == &ftrace_list_end)
3135 ftrace_trace_function = ftrace_list->func;
3137 ftrace_trace_function = ftrace_list_func;
3141 /* stopping ftrace calls (just send to ftrace_stub) */
3142 ftrace_trace_function = ftrace_stub;
3144 ftrace_shutdown_sysctl();
3148 mutex_unlock(&ftrace_lock);
3152 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3154 static int ftrace_graph_active;
3155 static struct notifier_block ftrace_suspend_notifier;
3157 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3162 /* The callbacks that hook a function */
3163 trace_func_graph_ret_t ftrace_graph_return =
3164 (trace_func_graph_ret_t)ftrace_stub;
3165 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3167 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3168 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3172 unsigned long flags;
3173 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3174 struct task_struct *g, *t;
3176 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3177 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3178 * sizeof(struct ftrace_ret_stack),
3180 if (!ret_stack_list[i]) {
3188 read_lock_irqsave(&tasklist_lock, flags);
3189 do_each_thread(g, t) {
3195 if (t->ret_stack == NULL) {
3196 atomic_set(&t->tracing_graph_pause, 0);
3197 atomic_set(&t->trace_overrun, 0);
3198 t->curr_ret_stack = -1;
3199 /* Make sure the tasks see the -1 first: */
3201 t->ret_stack = ret_stack_list[start++];
3203 } while_each_thread(g, t);
3206 read_unlock_irqrestore(&tasklist_lock, flags);
3208 for (i = start; i < end; i++)
3209 kfree(ret_stack_list[i]);
3214 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3215 struct task_struct *next)
3217 unsigned long long timestamp;
3221 * Does the user want to count the time a function was asleep.
3222 * If so, do not update the time stamps.
3224 if (trace_flags & TRACE_ITER_SLEEP_TIME)
3227 timestamp = trace_clock_local();
3229 prev->ftrace_timestamp = timestamp;
3231 /* only process tasks that we timestamped */
3232 if (!next->ftrace_timestamp)
3236 * Update all the counters in next to make up for the
3237 * time next was sleeping.
3239 timestamp -= next->ftrace_timestamp;
3241 for (index = next->curr_ret_stack; index >= 0; index--)
3242 next->ret_stack[index].calltime += timestamp;
3245 /* Allocate a return stack for each task */
3246 static int start_graph_tracing(void)
3248 struct ftrace_ret_stack **ret_stack_list;
3251 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3252 sizeof(struct ftrace_ret_stack *),
3255 if (!ret_stack_list)
3258 /* The cpu_boot init_task->ret_stack will never be freed */
3259 for_each_online_cpu(cpu) {
3260 if (!idle_task(cpu)->ret_stack)
3261 ftrace_graph_init_task(idle_task(cpu));
3265 ret = alloc_retstack_tasklist(ret_stack_list);
3266 } while (ret == -EAGAIN);
3269 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3271 pr_info("ftrace_graph: Couldn't activate tracepoint"
3272 " probe to kernel_sched_switch\n");
3275 kfree(ret_stack_list);
3280 * Hibernation protection.
3281 * The state of the current task is too much unstable during
3282 * suspend/restore to disk. We want to protect against that.
3285 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3289 case PM_HIBERNATION_PREPARE:
3290 pause_graph_tracing();
3293 case PM_POST_HIBERNATION:
3294 unpause_graph_tracing();
3300 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3301 trace_func_graph_ent_t entryfunc)
3305 mutex_lock(&ftrace_lock);
3307 /* we currently allow only one tracer registered at a time */
3308 if (ftrace_graph_active) {
3313 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3314 register_pm_notifier(&ftrace_suspend_notifier);
3316 ftrace_graph_active++;
3317 ret = start_graph_tracing();
3319 ftrace_graph_active--;
3323 ftrace_graph_return = retfunc;
3324 ftrace_graph_entry = entryfunc;
3326 ftrace_startup(FTRACE_START_FUNC_RET);
3329 mutex_unlock(&ftrace_lock);
3333 void unregister_ftrace_graph(void)
3335 mutex_lock(&ftrace_lock);
3337 if (unlikely(!ftrace_graph_active))
3340 ftrace_graph_active--;
3341 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3342 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3343 ftrace_graph_entry = ftrace_graph_entry_stub;
3344 ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3345 unregister_pm_notifier(&ftrace_suspend_notifier);
3348 mutex_unlock(&ftrace_lock);
3351 /* Allocate a return stack for newly created task */
3352 void ftrace_graph_init_task(struct task_struct *t)
3354 /* Make sure we do not use the parent ret_stack */
3355 t->ret_stack = NULL;
3356 t->curr_ret_stack = -1;
3358 if (ftrace_graph_active) {
3359 struct ftrace_ret_stack *ret_stack;
3361 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3362 * sizeof(struct ftrace_ret_stack),
3366 atomic_set(&t->tracing_graph_pause, 0);
3367 atomic_set(&t->trace_overrun, 0);
3368 t->ftrace_timestamp = 0;
3369 /* make curr_ret_stack visable before we add the ret_stack */
3371 t->ret_stack = ret_stack;
3375 void ftrace_graph_exit_task(struct task_struct *t)
3377 struct ftrace_ret_stack *ret_stack = t->ret_stack;
3379 t->ret_stack = NULL;
3380 /* NULL must become visible to IRQs before we free it: */
3386 void ftrace_graph_stop(void)