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 Nadia Yvette Chambers
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/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
36 #include <trace/events/sched.h>
38 #include <asm/setup.h>
40 #include "trace_output.h"
41 #include "trace_stat.h"
43 #define FTRACE_WARN_ON(cond) \
51 #define FTRACE_WARN_ON_ONCE(cond) \
54 if (WARN_ON_ONCE(___r)) \
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
67 #ifdef CONFIG_DYNAMIC_FTRACE
68 #define INIT_REGEX_LOCK(opsname) \
69 .regex_lock = __MUTEX_INITIALIZER(opsname.regex_lock),
71 #define INIT_REGEX_LOCK(opsname)
74 static struct ftrace_ops ftrace_list_end __read_mostly = {
76 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
79 /* ftrace_enabled is a method to turn ftrace on or off */
80 int ftrace_enabled __read_mostly;
81 static int last_ftrace_enabled;
83 /* Quick disabling of function tracer. */
84 int function_trace_stop __read_mostly;
86 /* Current function tracing op */
87 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
88 /* What to set function_trace_op to */
89 static struct ftrace_ops *set_function_trace_op;
91 /* List for set_ftrace_pid's pids. */
92 LIST_HEAD(ftrace_pids);
94 struct list_head list;
99 * ftrace_disabled is set when an anomaly is discovered.
100 * ftrace_disabled is much stronger than ftrace_enabled.
102 static int ftrace_disabled __read_mostly;
104 static DEFINE_MUTEX(ftrace_lock);
106 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
107 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
108 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
109 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
110 static struct ftrace_ops global_ops;
111 static struct ftrace_ops control_ops;
113 #if ARCH_SUPPORTS_FTRACE_OPS
114 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
115 struct ftrace_ops *op, struct pt_regs *regs);
117 /* See comment below, where ftrace_ops_list_func is defined */
118 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
119 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
123 * Traverse the ftrace_global_list, invoking all entries. The reason that we
124 * can use rcu_dereference_raw_notrace() is that elements removed from this list
125 * are simply leaked, so there is no need to interact with a grace-period
126 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
127 * concurrent insertions into the ftrace_global_list.
129 * Silly Alpha and silly pointer-speculation compiler optimizations!
131 #define do_for_each_ftrace_op(op, list) \
132 op = rcu_dereference_raw_notrace(list); \
136 * Optimized for just a single item in the list (as that is the normal case).
138 #define while_for_each_ftrace_op(op) \
139 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
140 unlikely((op) != &ftrace_list_end))
142 static inline void ftrace_ops_init(struct ftrace_ops *ops)
144 #ifdef CONFIG_DYNAMIC_FTRACE
145 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
146 mutex_init(&ops->regex_lock);
147 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
153 * ftrace_nr_registered_ops - return number of ops registered
155 * Returns the number of ftrace_ops registered and tracing functions
157 int ftrace_nr_registered_ops(void)
159 struct ftrace_ops *ops;
162 mutex_lock(&ftrace_lock);
164 for (ops = ftrace_ops_list;
165 ops != &ftrace_list_end; ops = ops->next)
168 mutex_unlock(&ftrace_lock);
173 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
174 struct ftrace_ops *op, struct pt_regs *regs)
176 if (!test_tsk_trace_trace(current))
179 ftrace_pid_function(ip, parent_ip, op, regs);
182 static void set_ftrace_pid_function(ftrace_func_t func)
184 /* do not set ftrace_pid_function to itself! */
185 if (func != ftrace_pid_func)
186 ftrace_pid_function = func;
190 * clear_ftrace_function - reset the ftrace function
192 * This NULLs the ftrace function and in essence stops
193 * tracing. There may be lag
195 void clear_ftrace_function(void)
197 ftrace_trace_function = ftrace_stub;
198 ftrace_pid_function = ftrace_stub;
201 static void control_ops_disable_all(struct ftrace_ops *ops)
205 for_each_possible_cpu(cpu)
206 *per_cpu_ptr(ops->disabled, cpu) = 1;
209 static int control_ops_alloc(struct ftrace_ops *ops)
211 int __percpu *disabled;
213 disabled = alloc_percpu(int);
217 ops->disabled = disabled;
218 control_ops_disable_all(ops);
222 static void ftrace_sync(struct work_struct *work)
225 * This function is just a stub to implement a hard force
226 * of synchronize_sched(). This requires synchronizing
227 * tasks even in userspace and idle.
229 * Yes, function tracing is rude.
233 static void ftrace_sync_ipi(void *data)
235 /* Probably not needed, but do it anyway */
239 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
240 static void update_function_graph_func(void);
242 static inline void update_function_graph_func(void) { }
245 static void update_ftrace_function(void)
250 * If we are at the end of the list and this ops is
251 * recursion safe and not dynamic and the arch supports passing ops,
252 * then have the mcount trampoline call the function directly.
254 if (ftrace_ops_list == &ftrace_list_end ||
255 (ftrace_ops_list->next == &ftrace_list_end &&
256 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
257 (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
258 !FTRACE_FORCE_LIST_FUNC)) {
259 /* Set the ftrace_ops that the arch callback uses */
260 set_function_trace_op = ftrace_ops_list;
261 func = ftrace_ops_list->func;
263 /* Just use the default ftrace_ops */
264 set_function_trace_op = &ftrace_list_end;
265 func = ftrace_ops_list_func;
268 /* If there's no change, then do nothing more here */
269 if (ftrace_trace_function == func)
272 update_function_graph_func();
275 * If we are using the list function, it doesn't care
276 * about the function_trace_ops.
278 if (func == ftrace_ops_list_func) {
279 ftrace_trace_function = func;
281 * Don't even bother setting function_trace_ops,
282 * it would be racy to do so anyway.
287 #ifndef CONFIG_DYNAMIC_FTRACE
289 * For static tracing, we need to be a bit more careful.
290 * The function change takes affect immediately. Thus,
291 * we need to coorditate the setting of the function_trace_ops
292 * with the setting of the ftrace_trace_function.
294 * Set the function to the list ops, which will call the
295 * function we want, albeit indirectly, but it handles the
296 * ftrace_ops and doesn't depend on function_trace_op.
298 ftrace_trace_function = ftrace_ops_list_func;
300 * Make sure all CPUs see this. Yes this is slow, but static
301 * tracing is slow and nasty to have enabled.
303 schedule_on_each_cpu(ftrace_sync);
304 /* Now all cpus are using the list ops. */
305 function_trace_op = set_function_trace_op;
306 /* Make sure the function_trace_op is visible on all CPUs */
308 /* Nasty way to force a rmb on all cpus */
309 smp_call_function(ftrace_sync_ipi, NULL, 1);
310 /* OK, we are all set to update the ftrace_trace_function now! */
311 #endif /* !CONFIG_DYNAMIC_FTRACE */
313 ftrace_trace_function = func;
316 int using_ftrace_ops_list_func(void)
318 return ftrace_trace_function == ftrace_ops_list_func;
321 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
325 * We are entering ops into the list but another
326 * CPU might be walking that list. We need to make sure
327 * the ops->next pointer is valid before another CPU sees
328 * the ops pointer included into the list.
330 rcu_assign_pointer(*list, ops);
333 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
335 struct ftrace_ops **p;
338 * If we are removing the last function, then simply point
339 * to the ftrace_stub.
341 if (*list == ops && ops->next == &ftrace_list_end) {
342 *list = &ftrace_list_end;
346 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
357 static void add_ftrace_list_ops(struct ftrace_ops **list,
358 struct ftrace_ops *main_ops,
359 struct ftrace_ops *ops)
361 int first = *list == &ftrace_list_end;
362 add_ftrace_ops(list, ops);
364 add_ftrace_ops(&ftrace_ops_list, main_ops);
367 static int remove_ftrace_list_ops(struct ftrace_ops **list,
368 struct ftrace_ops *main_ops,
369 struct ftrace_ops *ops)
371 int ret = remove_ftrace_ops(list, ops);
372 if (!ret && *list == &ftrace_list_end)
373 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
377 static int __register_ftrace_function(struct ftrace_ops *ops)
379 if (ops->flags & FTRACE_OPS_FL_DELETED)
382 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
385 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
387 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
388 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
389 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
391 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
392 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
395 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
396 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
399 if (!core_kernel_data((unsigned long)ops))
400 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
402 if (ops->flags & FTRACE_OPS_FL_CONTROL) {
403 if (control_ops_alloc(ops))
405 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
407 add_ftrace_ops(&ftrace_ops_list, ops);
410 update_ftrace_function();
415 static int __unregister_ftrace_function(struct ftrace_ops *ops)
419 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
422 if (ops->flags & FTRACE_OPS_FL_CONTROL) {
423 ret = remove_ftrace_list_ops(&ftrace_control_list,
426 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
432 update_ftrace_function();
437 static void ftrace_update_pid_func(void)
439 /* Only do something if we are tracing something */
440 if (ftrace_trace_function == ftrace_stub)
443 update_ftrace_function();
446 #ifdef CONFIG_FUNCTION_PROFILER
447 struct ftrace_profile {
448 struct hlist_node node;
450 unsigned long counter;
451 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
452 unsigned long long time;
453 unsigned long long time_squared;
457 struct ftrace_profile_page {
458 struct ftrace_profile_page *next;
460 struct ftrace_profile records[];
463 struct ftrace_profile_stat {
465 struct hlist_head *hash;
466 struct ftrace_profile_page *pages;
467 struct ftrace_profile_page *start;
468 struct tracer_stat stat;
471 #define PROFILE_RECORDS_SIZE \
472 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
474 #define PROFILES_PER_PAGE \
475 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
477 static int ftrace_profile_enabled __read_mostly;
479 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
480 static DEFINE_MUTEX(ftrace_profile_lock);
482 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
484 #define FTRACE_PROFILE_HASH_BITS 10
485 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
488 function_stat_next(void *v, int idx)
490 struct ftrace_profile *rec = v;
491 struct ftrace_profile_page *pg;
493 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
499 if ((void *)rec >= (void *)&pg->records[pg->index]) {
503 rec = &pg->records[0];
511 static void *function_stat_start(struct tracer_stat *trace)
513 struct ftrace_profile_stat *stat =
514 container_of(trace, struct ftrace_profile_stat, stat);
516 if (!stat || !stat->start)
519 return function_stat_next(&stat->start->records[0], 0);
522 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
523 /* function graph compares on total time */
524 static int function_stat_cmp(void *p1, void *p2)
526 struct ftrace_profile *a = p1;
527 struct ftrace_profile *b = p2;
529 if (a->time < b->time)
531 if (a->time > b->time)
537 /* not function graph compares against hits */
538 static int function_stat_cmp(void *p1, void *p2)
540 struct ftrace_profile *a = p1;
541 struct ftrace_profile *b = p2;
543 if (a->counter < b->counter)
545 if (a->counter > b->counter)
552 static int function_stat_headers(struct seq_file *m)
554 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
555 seq_printf(m, " Function "
558 "--- ---- --- ---\n");
560 seq_printf(m, " Function Hit\n"
566 static int function_stat_show(struct seq_file *m, void *v)
568 struct ftrace_profile *rec = v;
569 char str[KSYM_SYMBOL_LEN];
571 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
572 static struct trace_seq s;
573 unsigned long long avg;
574 unsigned long long stddev;
576 mutex_lock(&ftrace_profile_lock);
578 /* we raced with function_profile_reset() */
579 if (unlikely(rec->counter == 0)) {
584 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
585 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
587 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
590 do_div(avg, rec->counter);
592 /* Sample standard deviation (s^2) */
593 if (rec->counter <= 1)
597 * Apply Welford's method:
598 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
600 stddev = rec->counter * rec->time_squared -
601 rec->time * rec->time;
604 * Divide only 1000 for ns^2 -> us^2 conversion.
605 * trace_print_graph_duration will divide 1000 again.
607 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
611 trace_print_graph_duration(rec->time, &s);
612 trace_seq_puts(&s, " ");
613 trace_print_graph_duration(avg, &s);
614 trace_seq_puts(&s, " ");
615 trace_print_graph_duration(stddev, &s);
616 trace_print_seq(m, &s);
620 mutex_unlock(&ftrace_profile_lock);
625 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
627 struct ftrace_profile_page *pg;
629 pg = stat->pages = stat->start;
632 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
637 memset(stat->hash, 0,
638 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
641 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
643 struct ftrace_profile_page *pg;
648 /* If we already allocated, do nothing */
652 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
656 #ifdef CONFIG_DYNAMIC_FTRACE
657 functions = ftrace_update_tot_cnt;
660 * We do not know the number of functions that exist because
661 * dynamic tracing is what counts them. With past experience
662 * we have around 20K functions. That should be more than enough.
663 * It is highly unlikely we will execute every function in
669 pg = stat->start = stat->pages;
671 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
673 for (i = 1; i < pages; i++) {
674 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
685 unsigned long tmp = (unsigned long)pg;
697 static int ftrace_profile_init_cpu(int cpu)
699 struct ftrace_profile_stat *stat;
702 stat = &per_cpu(ftrace_profile_stats, cpu);
705 /* If the profile is already created, simply reset it */
706 ftrace_profile_reset(stat);
711 * We are profiling all functions, but usually only a few thousand
712 * functions are hit. We'll make a hash of 1024 items.
714 size = FTRACE_PROFILE_HASH_SIZE;
716 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
721 /* Preallocate the function profiling pages */
722 if (ftrace_profile_pages_init(stat) < 0) {
731 static int ftrace_profile_init(void)
736 for_each_possible_cpu(cpu) {
737 ret = ftrace_profile_init_cpu(cpu);
745 /* interrupts must be disabled */
746 static struct ftrace_profile *
747 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
749 struct ftrace_profile *rec;
750 struct hlist_head *hhd;
753 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
754 hhd = &stat->hash[key];
756 if (hlist_empty(hhd))
759 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
767 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
768 struct ftrace_profile *rec)
772 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
773 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
777 * The memory is already allocated, this simply finds a new record to use.
779 static struct ftrace_profile *
780 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
782 struct ftrace_profile *rec = NULL;
784 /* prevent recursion (from NMIs) */
785 if (atomic_inc_return(&stat->disabled) != 1)
789 * Try to find the function again since an NMI
790 * could have added it
792 rec = ftrace_find_profiled_func(stat, ip);
796 if (stat->pages->index == PROFILES_PER_PAGE) {
797 if (!stat->pages->next)
799 stat->pages = stat->pages->next;
802 rec = &stat->pages->records[stat->pages->index++];
804 ftrace_add_profile(stat, rec);
807 atomic_dec(&stat->disabled);
813 function_profile_call(unsigned long ip, unsigned long parent_ip,
814 struct ftrace_ops *ops, struct pt_regs *regs)
816 struct ftrace_profile_stat *stat;
817 struct ftrace_profile *rec;
820 if (!ftrace_profile_enabled)
823 local_irq_save(flags);
825 stat = this_cpu_ptr(&ftrace_profile_stats);
826 if (!stat->hash || !ftrace_profile_enabled)
829 rec = ftrace_find_profiled_func(stat, ip);
831 rec = ftrace_profile_alloc(stat, ip);
838 local_irq_restore(flags);
841 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
842 static int profile_graph_entry(struct ftrace_graph_ent *trace)
844 function_profile_call(trace->func, 0, NULL, NULL);
848 static void profile_graph_return(struct ftrace_graph_ret *trace)
850 struct ftrace_profile_stat *stat;
851 unsigned long long calltime;
852 struct ftrace_profile *rec;
855 local_irq_save(flags);
856 stat = this_cpu_ptr(&ftrace_profile_stats);
857 if (!stat->hash || !ftrace_profile_enabled)
860 /* If the calltime was zero'd ignore it */
861 if (!trace->calltime)
864 calltime = trace->rettime - trace->calltime;
866 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
869 index = trace->depth;
871 /* Append this call time to the parent time to subtract */
873 current->ret_stack[index - 1].subtime += calltime;
875 if (current->ret_stack[index].subtime < calltime)
876 calltime -= current->ret_stack[index].subtime;
881 rec = ftrace_find_profiled_func(stat, trace->func);
883 rec->time += calltime;
884 rec->time_squared += calltime * calltime;
888 local_irq_restore(flags);
891 static int register_ftrace_profiler(void)
893 return register_ftrace_graph(&profile_graph_return,
894 &profile_graph_entry);
897 static void unregister_ftrace_profiler(void)
899 unregister_ftrace_graph();
902 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
903 .func = function_profile_call,
904 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
905 INIT_REGEX_LOCK(ftrace_profile_ops)
908 static int register_ftrace_profiler(void)
910 return register_ftrace_function(&ftrace_profile_ops);
913 static void unregister_ftrace_profiler(void)
915 unregister_ftrace_function(&ftrace_profile_ops);
917 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
920 ftrace_profile_write(struct file *filp, const char __user *ubuf,
921 size_t cnt, loff_t *ppos)
926 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
932 mutex_lock(&ftrace_profile_lock);
933 if (ftrace_profile_enabled ^ val) {
935 ret = ftrace_profile_init();
941 ret = register_ftrace_profiler();
946 ftrace_profile_enabled = 1;
948 ftrace_profile_enabled = 0;
950 * unregister_ftrace_profiler calls stop_machine
951 * so this acts like an synchronize_sched.
953 unregister_ftrace_profiler();
957 mutex_unlock(&ftrace_profile_lock);
965 ftrace_profile_read(struct file *filp, char __user *ubuf,
966 size_t cnt, loff_t *ppos)
968 char buf[64]; /* big enough to hold a number */
971 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
972 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
975 static const struct file_operations ftrace_profile_fops = {
976 .open = tracing_open_generic,
977 .read = ftrace_profile_read,
978 .write = ftrace_profile_write,
979 .llseek = default_llseek,
982 /* used to initialize the real stat files */
983 static struct tracer_stat function_stats __initdata = {
985 .stat_start = function_stat_start,
986 .stat_next = function_stat_next,
987 .stat_cmp = function_stat_cmp,
988 .stat_headers = function_stat_headers,
989 .stat_show = function_stat_show
992 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
994 struct ftrace_profile_stat *stat;
995 struct dentry *entry;
1000 for_each_possible_cpu(cpu) {
1001 stat = &per_cpu(ftrace_profile_stats, cpu);
1003 /* allocate enough for function name + cpu number */
1004 name = kmalloc(32, GFP_KERNEL);
1007 * The files created are permanent, if something happens
1008 * we still do not free memory.
1011 "Could not allocate stat file for cpu %d\n",
1015 stat->stat = function_stats;
1016 snprintf(name, 32, "function%d", cpu);
1017 stat->stat.name = name;
1018 ret = register_stat_tracer(&stat->stat);
1021 "Could not register function stat for cpu %d\n",
1028 entry = debugfs_create_file("function_profile_enabled", 0644,
1029 d_tracer, NULL, &ftrace_profile_fops);
1031 pr_warning("Could not create debugfs "
1032 "'function_profile_enabled' entry\n");
1035 #else /* CONFIG_FUNCTION_PROFILER */
1036 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1039 #endif /* CONFIG_FUNCTION_PROFILER */
1041 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1043 #ifdef CONFIG_DYNAMIC_FTRACE
1045 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1046 # error Dynamic ftrace depends on MCOUNT_RECORD
1049 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1051 struct ftrace_func_probe {
1052 struct hlist_node node;
1053 struct ftrace_probe_ops *ops;
1054 unsigned long flags;
1057 struct list_head free_list;
1060 struct ftrace_func_entry {
1061 struct hlist_node hlist;
1065 struct ftrace_hash {
1066 unsigned long size_bits;
1067 struct hlist_head *buckets;
1068 unsigned long count;
1069 struct rcu_head rcu;
1073 * We make these constant because no one should touch them,
1074 * but they are used as the default "empty hash", to avoid allocating
1075 * it all the time. These are in a read only section such that if
1076 * anyone does try to modify it, it will cause an exception.
1078 static const struct hlist_head empty_buckets[1];
1079 static const struct ftrace_hash empty_hash = {
1080 .buckets = (struct hlist_head *)empty_buckets,
1082 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1084 static struct ftrace_ops global_ops = {
1085 .func = ftrace_stub,
1086 .notrace_hash = EMPTY_HASH,
1087 .filter_hash = EMPTY_HASH,
1088 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1089 INIT_REGEX_LOCK(global_ops)
1092 struct ftrace_page {
1093 struct ftrace_page *next;
1094 struct dyn_ftrace *records;
1099 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1100 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1102 /* estimate from running different kernels */
1103 #define NR_TO_INIT 10000
1105 static struct ftrace_page *ftrace_pages_start;
1106 static struct ftrace_page *ftrace_pages;
1108 static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1110 return !hash || !hash->count;
1113 static struct ftrace_func_entry *
1114 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1117 struct ftrace_func_entry *entry;
1118 struct hlist_head *hhd;
1120 if (ftrace_hash_empty(hash))
1123 if (hash->size_bits > 0)
1124 key = hash_long(ip, hash->size_bits);
1128 hhd = &hash->buckets[key];
1130 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1131 if (entry->ip == ip)
1137 static void __add_hash_entry(struct ftrace_hash *hash,
1138 struct ftrace_func_entry *entry)
1140 struct hlist_head *hhd;
1143 if (hash->size_bits)
1144 key = hash_long(entry->ip, hash->size_bits);
1148 hhd = &hash->buckets[key];
1149 hlist_add_head(&entry->hlist, hhd);
1153 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1155 struct ftrace_func_entry *entry;
1157 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1162 __add_hash_entry(hash, entry);
1168 free_hash_entry(struct ftrace_hash *hash,
1169 struct ftrace_func_entry *entry)
1171 hlist_del(&entry->hlist);
1177 remove_hash_entry(struct ftrace_hash *hash,
1178 struct ftrace_func_entry *entry)
1180 hlist_del(&entry->hlist);
1184 static void ftrace_hash_clear(struct ftrace_hash *hash)
1186 struct hlist_head *hhd;
1187 struct hlist_node *tn;
1188 struct ftrace_func_entry *entry;
1189 int size = 1 << hash->size_bits;
1195 for (i = 0; i < size; i++) {
1196 hhd = &hash->buckets[i];
1197 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1198 free_hash_entry(hash, entry);
1200 FTRACE_WARN_ON(hash->count);
1203 static void free_ftrace_hash(struct ftrace_hash *hash)
1205 if (!hash || hash == EMPTY_HASH)
1207 ftrace_hash_clear(hash);
1208 kfree(hash->buckets);
1212 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1214 struct ftrace_hash *hash;
1216 hash = container_of(rcu, struct ftrace_hash, rcu);
1217 free_ftrace_hash(hash);
1220 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1222 if (!hash || hash == EMPTY_HASH)
1224 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1227 void ftrace_free_filter(struct ftrace_ops *ops)
1229 ftrace_ops_init(ops);
1230 free_ftrace_hash(ops->filter_hash);
1231 free_ftrace_hash(ops->notrace_hash);
1234 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1236 struct ftrace_hash *hash;
1239 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1243 size = 1 << size_bits;
1244 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1246 if (!hash->buckets) {
1251 hash->size_bits = size_bits;
1256 static struct ftrace_hash *
1257 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1259 struct ftrace_func_entry *entry;
1260 struct ftrace_hash *new_hash;
1265 new_hash = alloc_ftrace_hash(size_bits);
1270 if (ftrace_hash_empty(hash))
1273 size = 1 << hash->size_bits;
1274 for (i = 0; i < size; i++) {
1275 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1276 ret = add_hash_entry(new_hash, entry->ip);
1282 FTRACE_WARN_ON(new_hash->count != hash->count);
1287 free_ftrace_hash(new_hash);
1292 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1294 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1297 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1298 struct ftrace_hash **dst, struct ftrace_hash *src)
1300 struct ftrace_func_entry *entry;
1301 struct hlist_node *tn;
1302 struct hlist_head *hhd;
1303 struct ftrace_hash *old_hash;
1304 struct ftrace_hash *new_hash;
1305 int size = src->count;
1311 * Remove the current set, update the hash and add
1314 ftrace_hash_rec_disable(ops, enable);
1317 * If the new source is empty, just free dst and assign it
1321 free_ftrace_hash_rcu(*dst);
1322 rcu_assign_pointer(*dst, EMPTY_HASH);
1323 /* still need to update the function records */
1329 * Make the hash size about 1/2 the # found
1331 for (size /= 2; size; size >>= 1)
1334 /* Don't allocate too much */
1335 if (bits > FTRACE_HASH_MAX_BITS)
1336 bits = FTRACE_HASH_MAX_BITS;
1339 new_hash = alloc_ftrace_hash(bits);
1343 size = 1 << src->size_bits;
1344 for (i = 0; i < size; i++) {
1345 hhd = &src->buckets[i];
1346 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1347 remove_hash_entry(src, entry);
1348 __add_hash_entry(new_hash, entry);
1353 rcu_assign_pointer(*dst, new_hash);
1354 free_ftrace_hash_rcu(old_hash);
1359 * Enable regardless of ret:
1360 * On success, we enable the new hash.
1361 * On failure, we re-enable the original hash.
1363 ftrace_hash_rec_enable(ops, enable);
1369 * Test the hashes for this ops to see if we want to call
1370 * the ops->func or not.
1372 * It's a match if the ip is in the ops->filter_hash or
1373 * the filter_hash does not exist or is empty,
1375 * the ip is not in the ops->notrace_hash.
1377 * This needs to be called with preemption disabled as
1378 * the hashes are freed with call_rcu_sched().
1381 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1383 struct ftrace_hash *filter_hash;
1384 struct ftrace_hash *notrace_hash;
1387 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1389 * There's a small race when adding ops that the ftrace handler
1390 * that wants regs, may be called without them. We can not
1391 * allow that handler to be called if regs is NULL.
1393 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1397 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1398 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1400 if ((ftrace_hash_empty(filter_hash) ||
1401 ftrace_lookup_ip(filter_hash, ip)) &&
1402 (ftrace_hash_empty(notrace_hash) ||
1403 !ftrace_lookup_ip(notrace_hash, ip)))
1412 * This is a double for. Do not use 'break' to break out of the loop,
1413 * you must use a goto.
1415 #define do_for_each_ftrace_rec(pg, rec) \
1416 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1418 for (_____i = 0; _____i < pg->index; _____i++) { \
1419 rec = &pg->records[_____i];
1421 #define while_for_each_ftrace_rec() \
1426 static int ftrace_cmp_recs(const void *a, const void *b)
1428 const struct dyn_ftrace *key = a;
1429 const struct dyn_ftrace *rec = b;
1431 if (key->flags < rec->ip)
1433 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1438 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1440 struct ftrace_page *pg;
1441 struct dyn_ftrace *rec;
1442 struct dyn_ftrace key;
1445 key.flags = end; /* overload flags, as it is unsigned long */
1447 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1448 if (end < pg->records[0].ip ||
1449 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1451 rec = bsearch(&key, pg->records, pg->index,
1452 sizeof(struct dyn_ftrace),
1462 * ftrace_location - return true if the ip giving is a traced location
1463 * @ip: the instruction pointer to check
1465 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1466 * That is, the instruction that is either a NOP or call to
1467 * the function tracer. It checks the ftrace internal tables to
1468 * determine if the address belongs or not.
1470 unsigned long ftrace_location(unsigned long ip)
1472 return ftrace_location_range(ip, ip);
1476 * ftrace_text_reserved - return true if range contains an ftrace location
1477 * @start: start of range to search
1478 * @end: end of range to search (inclusive). @end points to the last byte to check.
1480 * Returns 1 if @start and @end contains a ftrace location.
1481 * That is, the instruction that is either a NOP or call to
1482 * the function tracer. It checks the ftrace internal tables to
1483 * determine if the address belongs or not.
1485 int ftrace_text_reserved(const void *start, const void *end)
1489 ret = ftrace_location_range((unsigned long)start,
1490 (unsigned long)end);
1495 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1499 struct ftrace_hash *hash;
1500 struct ftrace_hash *other_hash;
1501 struct ftrace_page *pg;
1502 struct dyn_ftrace *rec;
1506 /* Only update if the ops has been registered */
1507 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1511 * In the filter_hash case:
1512 * If the count is zero, we update all records.
1513 * Otherwise we just update the items in the hash.
1515 * In the notrace_hash case:
1516 * We enable the update in the hash.
1517 * As disabling notrace means enabling the tracing,
1518 * and enabling notrace means disabling, the inc variable
1522 hash = ops->filter_hash;
1523 other_hash = ops->notrace_hash;
1524 if (ftrace_hash_empty(hash))
1528 hash = ops->notrace_hash;
1529 other_hash = ops->filter_hash;
1531 * If the notrace hash has no items,
1532 * then there's nothing to do.
1534 if (ftrace_hash_empty(hash))
1538 do_for_each_ftrace_rec(pg, rec) {
1539 int in_other_hash = 0;
1545 * Only the filter_hash affects all records.
1546 * Update if the record is not in the notrace hash.
1548 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1551 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1552 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1555 * If filter_hash is set, we want to match all functions
1556 * that are in the hash but not in the other hash.
1558 * If filter_hash is not set, then we are decrementing.
1559 * That means we match anything that is in the hash
1560 * and also in the other_hash. That is, we need to turn
1561 * off functions in the other hash because they are disabled
1564 if (filter_hash && in_hash && !in_other_hash)
1566 else if (!filter_hash && in_hash &&
1567 (in_other_hash || ftrace_hash_empty(other_hash)))
1575 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1578 * If any ops wants regs saved for this function
1579 * then all ops will get saved regs.
1581 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1582 rec->flags |= FTRACE_FL_REGS;
1584 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1589 /* Shortcut, if we handled all records, we are done. */
1590 if (!all && count == hash->count)
1592 } while_for_each_ftrace_rec();
1595 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1598 __ftrace_hash_rec_update(ops, filter_hash, 0);
1601 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1604 __ftrace_hash_rec_update(ops, filter_hash, 1);
1607 static void print_ip_ins(const char *fmt, unsigned char *p)
1611 printk(KERN_CONT "%s", fmt);
1613 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1614 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1618 * ftrace_bug - report and shutdown function tracer
1619 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1620 * @ip: The address that failed
1622 * The arch code that enables or disables the function tracing
1623 * can call ftrace_bug() when it has detected a problem in
1624 * modifying the code. @failed should be one of either:
1625 * EFAULT - if the problem happens on reading the @ip address
1626 * EINVAL - if what is read at @ip is not what was expected
1627 * EPERM - if the problem happens on writting to the @ip address
1629 void ftrace_bug(int failed, unsigned long ip)
1633 FTRACE_WARN_ON_ONCE(1);
1634 pr_info("ftrace faulted on modifying ");
1638 FTRACE_WARN_ON_ONCE(1);
1639 pr_info("ftrace failed to modify ");
1641 print_ip_ins(" actual: ", (unsigned char *)ip);
1642 printk(KERN_CONT "\n");
1645 FTRACE_WARN_ON_ONCE(1);
1646 pr_info("ftrace faulted on writing ");
1650 FTRACE_WARN_ON_ONCE(1);
1651 pr_info("ftrace faulted on unknown error ");
1656 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1658 unsigned long flag = 0UL;
1661 * If we are updating calls:
1663 * If the record has a ref count, then we need to enable it
1664 * because someone is using it.
1666 * Otherwise we make sure its disabled.
1668 * If we are disabling calls, then disable all records that
1671 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1672 flag = FTRACE_FL_ENABLED;
1675 * If enabling and the REGS flag does not match the REGS_EN, then
1676 * do not ignore this record. Set flags to fail the compare against
1680 (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1681 flag |= FTRACE_FL_REGS;
1683 /* If the state of this record hasn't changed, then do nothing */
1684 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1685 return FTRACE_UPDATE_IGNORE;
1688 /* Save off if rec is being enabled (for return value) */
1689 flag ^= rec->flags & FTRACE_FL_ENABLED;
1692 rec->flags |= FTRACE_FL_ENABLED;
1693 if (flag & FTRACE_FL_REGS) {
1694 if (rec->flags & FTRACE_FL_REGS)
1695 rec->flags |= FTRACE_FL_REGS_EN;
1697 rec->flags &= ~FTRACE_FL_REGS_EN;
1702 * If this record is being updated from a nop, then
1703 * return UPDATE_MAKE_CALL.
1704 * Otherwise, if the EN flag is set, then return
1705 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1706 * from the non-save regs, to a save regs function.
1708 * return UPDATE_MODIFY_CALL to tell the caller to convert
1709 * from the save regs, to a non-save regs function.
1711 if (flag & FTRACE_FL_ENABLED)
1712 return FTRACE_UPDATE_MAKE_CALL;
1713 else if (rec->flags & FTRACE_FL_REGS_EN)
1714 return FTRACE_UPDATE_MODIFY_CALL_REGS;
1716 return FTRACE_UPDATE_MODIFY_CALL;
1720 /* If there's no more users, clear all flags */
1721 if (!(rec->flags & ~FTRACE_FL_MASK))
1724 /* Just disable the record (keep REGS state) */
1725 rec->flags &= ~FTRACE_FL_ENABLED;
1728 return FTRACE_UPDATE_MAKE_NOP;
1732 * ftrace_update_record, set a record that now is tracing or not
1733 * @rec: the record to update
1734 * @enable: set to 1 if the record is tracing, zero to force disable
1736 * The records that represent all functions that can be traced need
1737 * to be updated when tracing has been enabled.
1739 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1741 return ftrace_check_record(rec, enable, 1);
1745 * ftrace_test_record, check if the record has been enabled or not
1746 * @rec: the record to test
1747 * @enable: set to 1 to check if enabled, 0 if it is disabled
1749 * The arch code may need to test if a record is already set to
1750 * tracing to determine how to modify the function code that it
1753 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1755 return ftrace_check_record(rec, enable, 0);
1759 * ftrace_get_addr_new - Get the call address to set to
1760 * @rec: The ftrace record descriptor
1762 * If the record has the FTRACE_FL_REGS set, that means that it
1763 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
1764 * is not not set, then it wants to convert to the normal callback.
1766 * Returns the address of the trampoline to set to
1768 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
1770 if (rec->flags & FTRACE_FL_REGS)
1771 return (unsigned long)FTRACE_REGS_ADDR;
1773 return (unsigned long)FTRACE_ADDR;
1777 * ftrace_get_addr_curr - Get the call address that is already there
1778 * @rec: The ftrace record descriptor
1780 * The FTRACE_FL_REGS_EN is set when the record already points to
1781 * a function that saves all the regs. Basically the '_EN' version
1782 * represents the current state of the function.
1784 * Returns the address of the trampoline that is currently being called
1786 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
1788 if (rec->flags & FTRACE_FL_REGS_EN)
1789 return (unsigned long)FTRACE_REGS_ADDR;
1791 return (unsigned long)FTRACE_ADDR;
1795 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1797 unsigned long ftrace_old_addr;
1798 unsigned long ftrace_addr;
1801 ret = ftrace_update_record(rec, enable);
1803 if (rec->flags & FTRACE_FL_REGS)
1804 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1806 ftrace_addr = (unsigned long)FTRACE_ADDR;
1809 case FTRACE_UPDATE_IGNORE:
1812 case FTRACE_UPDATE_MAKE_CALL:
1813 return ftrace_make_call(rec, ftrace_addr);
1815 case FTRACE_UPDATE_MAKE_NOP:
1816 return ftrace_make_nop(NULL, rec, ftrace_addr);
1818 case FTRACE_UPDATE_MODIFY_CALL_REGS:
1819 case FTRACE_UPDATE_MODIFY_CALL:
1820 if (rec->flags & FTRACE_FL_REGS)
1821 ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1823 ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1825 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1828 return -1; /* unknow ftrace bug */
1831 void __weak ftrace_replace_code(int enable)
1833 struct dyn_ftrace *rec;
1834 struct ftrace_page *pg;
1837 if (unlikely(ftrace_disabled))
1840 do_for_each_ftrace_rec(pg, rec) {
1841 failed = __ftrace_replace_code(rec, enable);
1843 ftrace_bug(failed, rec->ip);
1844 /* Stop processing */
1847 } while_for_each_ftrace_rec();
1850 struct ftrace_rec_iter {
1851 struct ftrace_page *pg;
1856 * ftrace_rec_iter_start, start up iterating over traced functions
1858 * Returns an iterator handle that is used to iterate over all
1859 * the records that represent address locations where functions
1862 * May return NULL if no records are available.
1864 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1867 * We only use a single iterator.
1868 * Protected by the ftrace_lock mutex.
1870 static struct ftrace_rec_iter ftrace_rec_iter;
1871 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1873 iter->pg = ftrace_pages_start;
1876 /* Could have empty pages */
1877 while (iter->pg && !iter->pg->index)
1878 iter->pg = iter->pg->next;
1887 * ftrace_rec_iter_next, get the next record to process.
1888 * @iter: The handle to the iterator.
1890 * Returns the next iterator after the given iterator @iter.
1892 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1896 if (iter->index >= iter->pg->index) {
1897 iter->pg = iter->pg->next;
1900 /* Could have empty pages */
1901 while (iter->pg && !iter->pg->index)
1902 iter->pg = iter->pg->next;
1912 * ftrace_rec_iter_record, get the record at the iterator location
1913 * @iter: The current iterator location
1915 * Returns the record that the current @iter is at.
1917 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1919 return &iter->pg->records[iter->index];
1923 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1930 if (unlikely(ftrace_disabled))
1933 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1935 ftrace_bug(ret, ip);
1942 * archs can override this function if they must do something
1943 * before the modifying code is performed.
1945 int __weak ftrace_arch_code_modify_prepare(void)
1951 * archs can override this function if they must do something
1952 * after the modifying code is performed.
1954 int __weak ftrace_arch_code_modify_post_process(void)
1959 void ftrace_modify_all_code(int command)
1961 int update = command & FTRACE_UPDATE_TRACE_FUNC;
1965 * If the ftrace_caller calls a ftrace_ops func directly,
1966 * we need to make sure that it only traces functions it
1967 * expects to trace. When doing the switch of functions,
1968 * we need to update to the ftrace_ops_list_func first
1969 * before the transition between old and new calls are set,
1970 * as the ftrace_ops_list_func will check the ops hashes
1971 * to make sure the ops are having the right functions
1975 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
1976 if (FTRACE_WARN_ON(err))
1980 if (command & FTRACE_UPDATE_CALLS)
1981 ftrace_replace_code(1);
1982 else if (command & FTRACE_DISABLE_CALLS)
1983 ftrace_replace_code(0);
1985 if (update && ftrace_trace_function != ftrace_ops_list_func) {
1986 function_trace_op = set_function_trace_op;
1988 /* If irqs are disabled, we are in stop machine */
1989 if (!irqs_disabled())
1990 smp_call_function(ftrace_sync_ipi, NULL, 1);
1991 err = ftrace_update_ftrace_func(ftrace_trace_function);
1992 if (FTRACE_WARN_ON(err))
1996 if (command & FTRACE_START_FUNC_RET)
1997 err = ftrace_enable_ftrace_graph_caller();
1998 else if (command & FTRACE_STOP_FUNC_RET)
1999 err = ftrace_disable_ftrace_graph_caller();
2000 FTRACE_WARN_ON(err);
2003 static int __ftrace_modify_code(void *data)
2005 int *command = data;
2007 ftrace_modify_all_code(*command);
2013 * ftrace_run_stop_machine, go back to the stop machine method
2014 * @command: The command to tell ftrace what to do
2016 * If an arch needs to fall back to the stop machine method, the
2017 * it can call this function.
2019 void ftrace_run_stop_machine(int command)
2021 stop_machine(__ftrace_modify_code, &command, NULL);
2025 * arch_ftrace_update_code, modify the code to trace or not trace
2026 * @command: The command that needs to be done
2028 * Archs can override this function if it does not need to
2029 * run stop_machine() to modify code.
2031 void __weak arch_ftrace_update_code(int command)
2033 ftrace_run_stop_machine(command);
2036 static void ftrace_run_update_code(int command)
2040 ret = ftrace_arch_code_modify_prepare();
2041 FTRACE_WARN_ON(ret);
2045 * Do not call function tracer while we update the code.
2046 * We are in stop machine.
2048 function_trace_stop++;
2051 * By default we use stop_machine() to modify the code.
2052 * But archs can do what ever they want as long as it
2053 * is safe. The stop_machine() is the safest, but also
2054 * produces the most overhead.
2056 arch_ftrace_update_code(command);
2058 function_trace_stop--;
2060 ret = ftrace_arch_code_modify_post_process();
2061 FTRACE_WARN_ON(ret);
2064 static ftrace_func_t saved_ftrace_func;
2065 static int ftrace_start_up;
2066 static int global_start_up;
2068 static void control_ops_free(struct ftrace_ops *ops)
2070 free_percpu(ops->disabled);
2073 static void ftrace_startup_enable(int command)
2075 if (saved_ftrace_func != ftrace_trace_function) {
2076 saved_ftrace_func = ftrace_trace_function;
2077 command |= FTRACE_UPDATE_TRACE_FUNC;
2080 if (!command || !ftrace_enabled)
2083 ftrace_run_update_code(command);
2086 static int ftrace_startup(struct ftrace_ops *ops, int command)
2090 if (unlikely(ftrace_disabled))
2093 ret = __register_ftrace_function(ops);
2098 command |= FTRACE_UPDATE_CALLS;
2100 ops->flags |= FTRACE_OPS_FL_ENABLED;
2102 ftrace_hash_rec_enable(ops, 1);
2104 ftrace_startup_enable(command);
2109 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2113 if (unlikely(ftrace_disabled))
2116 ret = __unregister_ftrace_function(ops);
2122 * Just warn in case of unbalance, no need to kill ftrace, it's not
2123 * critical but the ftrace_call callers may be never nopped again after
2124 * further ftrace uses.
2126 WARN_ON_ONCE(ftrace_start_up < 0);
2128 ftrace_hash_rec_disable(ops, 1);
2130 if (!global_start_up)
2131 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2133 command |= FTRACE_UPDATE_CALLS;
2135 if (saved_ftrace_func != ftrace_trace_function) {
2136 saved_ftrace_func = ftrace_trace_function;
2137 command |= FTRACE_UPDATE_TRACE_FUNC;
2140 if (!command || !ftrace_enabled) {
2142 * If these are control ops, they still need their
2143 * per_cpu field freed. Since, function tracing is
2144 * not currently active, we can just free them
2145 * without synchronizing all CPUs.
2147 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2148 control_ops_free(ops);
2152 ftrace_run_update_code(command);
2155 * Dynamic ops may be freed, we must make sure that all
2156 * callers are done before leaving this function.
2157 * The same goes for freeing the per_cpu data of the control
2160 * Again, normal synchronize_sched() is not good enough.
2161 * We need to do a hard force of sched synchronization.
2162 * This is because we use preempt_disable() to do RCU, but
2163 * the function tracers can be called where RCU is not watching
2164 * (like before user_exit()). We can not rely on the RCU
2165 * infrastructure to do the synchronization, thus we must do it
2168 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2169 schedule_on_each_cpu(ftrace_sync);
2171 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2172 control_ops_free(ops);
2178 static void ftrace_startup_sysctl(void)
2180 if (unlikely(ftrace_disabled))
2183 /* Force update next time */
2184 saved_ftrace_func = NULL;
2185 /* ftrace_start_up is true if we want ftrace running */
2186 if (ftrace_start_up)
2187 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2190 static void ftrace_shutdown_sysctl(void)
2192 if (unlikely(ftrace_disabled))
2195 /* ftrace_start_up is true if ftrace is running */
2196 if (ftrace_start_up)
2197 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2200 static cycle_t ftrace_update_time;
2201 unsigned long ftrace_update_tot_cnt;
2203 static inline int ops_traces_mod(struct ftrace_ops *ops)
2206 * Filter_hash being empty will default to trace module.
2207 * But notrace hash requires a test of individual module functions.
2209 return ftrace_hash_empty(ops->filter_hash) &&
2210 ftrace_hash_empty(ops->notrace_hash);
2214 * Check if the current ops references the record.
2216 * If the ops traces all functions, then it was already accounted for.
2217 * If the ops does not trace the current record function, skip it.
2218 * If the ops ignores the function via notrace filter, skip it.
2221 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2223 /* If ops isn't enabled, ignore it */
2224 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2227 /* If ops traces all mods, we already accounted for it */
2228 if (ops_traces_mod(ops))
2231 /* The function must be in the filter */
2232 if (!ftrace_hash_empty(ops->filter_hash) &&
2233 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2236 /* If in notrace hash, we ignore it too */
2237 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2243 static int referenced_filters(struct dyn_ftrace *rec)
2245 struct ftrace_ops *ops;
2248 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2249 if (ops_references_rec(ops, rec))
2256 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2258 struct ftrace_page *pg;
2259 struct dyn_ftrace *p;
2260 cycle_t start, stop;
2261 unsigned long update_cnt = 0;
2262 unsigned long ref = 0;
2267 * When adding a module, we need to check if tracers are
2268 * currently enabled and if they are set to trace all functions.
2269 * If they are, we need to enable the module functions as well
2270 * as update the reference counts for those function records.
2273 struct ftrace_ops *ops;
2275 for (ops = ftrace_ops_list;
2276 ops != &ftrace_list_end; ops = ops->next) {
2277 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2278 if (ops_traces_mod(ops))
2286 start = ftrace_now(raw_smp_processor_id());
2288 for (pg = new_pgs; pg; pg = pg->next) {
2290 for (i = 0; i < pg->index; i++) {
2293 /* If something went wrong, bail without enabling anything */
2294 if (unlikely(ftrace_disabled))
2297 p = &pg->records[i];
2299 cnt += referenced_filters(p);
2303 * Do the initial record conversion from mcount jump
2304 * to the NOP instructions.
2306 if (!ftrace_code_disable(mod, p))
2312 * If the tracing is enabled, go ahead and enable the record.
2314 * The reason not to enable the record immediatelly is the
2315 * inherent check of ftrace_make_nop/ftrace_make_call for
2316 * correct previous instructions. Making first the NOP
2317 * conversion puts the module to the correct state, thus
2318 * passing the ftrace_make_call check.
2320 if (ftrace_start_up && cnt) {
2321 int failed = __ftrace_replace_code(p, 1);
2323 ftrace_bug(failed, p->ip);
2328 stop = ftrace_now(raw_smp_processor_id());
2329 ftrace_update_time = stop - start;
2330 ftrace_update_tot_cnt += update_cnt;
2335 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2340 if (WARN_ON(!count))
2343 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2346 * We want to fill as much as possible. No more than a page
2349 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2353 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2356 /* if we can't allocate this size, try something smaller */
2363 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2372 static struct ftrace_page *
2373 ftrace_allocate_pages(unsigned long num_to_init)
2375 struct ftrace_page *start_pg;
2376 struct ftrace_page *pg;
2383 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2388 * Try to allocate as much as possible in one continues
2389 * location that fills in all of the space. We want to
2390 * waste as little space as possible.
2393 cnt = ftrace_allocate_records(pg, num_to_init);
2401 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2412 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2413 free_pages((unsigned long)pg->records, order);
2414 start_pg = pg->next;
2418 pr_info("ftrace: FAILED to allocate memory for functions\n");
2422 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2424 struct ftrace_iterator {
2427 struct ftrace_page *pg;
2428 struct dyn_ftrace *func;
2429 struct ftrace_func_probe *probe;
2430 struct trace_parser parser;
2431 struct ftrace_hash *hash;
2432 struct ftrace_ops *ops;
2439 t_hash_next(struct seq_file *m, loff_t *pos)
2441 struct ftrace_iterator *iter = m->private;
2442 struct hlist_node *hnd = NULL;
2443 struct hlist_head *hhd;
2449 hnd = &iter->probe->node;
2451 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2454 hhd = &ftrace_func_hash[iter->hidx];
2456 if (hlist_empty(hhd)) {
2472 if (WARN_ON_ONCE(!hnd))
2475 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2480 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2482 struct ftrace_iterator *iter = m->private;
2486 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2489 if (iter->func_pos > *pos)
2493 for (l = 0; l <= (*pos - iter->func_pos); ) {
2494 p = t_hash_next(m, &l);
2501 /* Only set this if we have an item */
2502 iter->flags |= FTRACE_ITER_HASH;
2508 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2510 struct ftrace_func_probe *rec;
2513 if (WARN_ON_ONCE(!rec))
2516 if (rec->ops->print)
2517 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2519 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2522 seq_printf(m, ":%p", rec->data);
2529 t_next(struct seq_file *m, void *v, loff_t *pos)
2531 struct ftrace_iterator *iter = m->private;
2532 struct ftrace_ops *ops = iter->ops;
2533 struct dyn_ftrace *rec = NULL;
2535 if (unlikely(ftrace_disabled))
2538 if (iter->flags & FTRACE_ITER_HASH)
2539 return t_hash_next(m, pos);
2542 iter->pos = iter->func_pos = *pos;
2544 if (iter->flags & FTRACE_ITER_PRINTALL)
2545 return t_hash_start(m, pos);
2548 if (iter->idx >= iter->pg->index) {
2549 if (iter->pg->next) {
2550 iter->pg = iter->pg->next;
2555 rec = &iter->pg->records[iter->idx++];
2556 if (((iter->flags & FTRACE_ITER_FILTER) &&
2557 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2559 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2560 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2562 ((iter->flags & FTRACE_ITER_ENABLED) &&
2563 !(rec->flags & FTRACE_FL_ENABLED))) {
2571 return t_hash_start(m, pos);
2578 static void reset_iter_read(struct ftrace_iterator *iter)
2582 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2585 static void *t_start(struct seq_file *m, loff_t *pos)
2587 struct ftrace_iterator *iter = m->private;
2588 struct ftrace_ops *ops = iter->ops;
2592 mutex_lock(&ftrace_lock);
2594 if (unlikely(ftrace_disabled))
2598 * If an lseek was done, then reset and start from beginning.
2600 if (*pos < iter->pos)
2601 reset_iter_read(iter);
2604 * For set_ftrace_filter reading, if we have the filter
2605 * off, we can short cut and just print out that all
2606 * functions are enabled.
2608 if (iter->flags & FTRACE_ITER_FILTER &&
2609 ftrace_hash_empty(ops->filter_hash)) {
2611 return t_hash_start(m, pos);
2612 iter->flags |= FTRACE_ITER_PRINTALL;
2613 /* reset in case of seek/pread */
2614 iter->flags &= ~FTRACE_ITER_HASH;
2618 if (iter->flags & FTRACE_ITER_HASH)
2619 return t_hash_start(m, pos);
2622 * Unfortunately, we need to restart at ftrace_pages_start
2623 * every time we let go of the ftrace_mutex. This is because
2624 * those pointers can change without the lock.
2626 iter->pg = ftrace_pages_start;
2628 for (l = 0; l <= *pos; ) {
2629 p = t_next(m, p, &l);
2635 return t_hash_start(m, pos);
2640 static void t_stop(struct seq_file *m, void *p)
2642 mutex_unlock(&ftrace_lock);
2645 static int t_show(struct seq_file *m, void *v)
2647 struct ftrace_iterator *iter = m->private;
2648 struct dyn_ftrace *rec;
2650 if (iter->flags & FTRACE_ITER_HASH)
2651 return t_hash_show(m, iter);
2653 if (iter->flags & FTRACE_ITER_PRINTALL) {
2654 seq_printf(m, "#### all functions enabled ####\n");
2663 seq_printf(m, "%ps", (void *)rec->ip);
2664 if (iter->flags & FTRACE_ITER_ENABLED)
2665 seq_printf(m, " (%ld)%s",
2666 rec->flags & ~FTRACE_FL_MASK,
2667 rec->flags & FTRACE_FL_REGS ? " R" : "");
2668 seq_printf(m, "\n");
2673 static const struct seq_operations show_ftrace_seq_ops = {
2681 ftrace_avail_open(struct inode *inode, struct file *file)
2683 struct ftrace_iterator *iter;
2685 if (unlikely(ftrace_disabled))
2688 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2690 iter->pg = ftrace_pages_start;
2691 iter->ops = &global_ops;
2694 return iter ? 0 : -ENOMEM;
2698 ftrace_enabled_open(struct inode *inode, struct file *file)
2700 struct ftrace_iterator *iter;
2702 if (unlikely(ftrace_disabled))
2705 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2707 iter->pg = ftrace_pages_start;
2708 iter->flags = FTRACE_ITER_ENABLED;
2709 iter->ops = &global_ops;
2712 return iter ? 0 : -ENOMEM;
2715 static void ftrace_filter_reset(struct ftrace_hash *hash)
2717 mutex_lock(&ftrace_lock);
2718 ftrace_hash_clear(hash);
2719 mutex_unlock(&ftrace_lock);
2723 * ftrace_regex_open - initialize function tracer filter files
2724 * @ops: The ftrace_ops that hold the hash filters
2725 * @flag: The type of filter to process
2726 * @inode: The inode, usually passed in to your open routine
2727 * @file: The file, usually passed in to your open routine
2729 * ftrace_regex_open() initializes the filter files for the
2730 * @ops. Depending on @flag it may process the filter hash or
2731 * the notrace hash of @ops. With this called from the open
2732 * routine, you can use ftrace_filter_write() for the write
2733 * routine if @flag has FTRACE_ITER_FILTER set, or
2734 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2735 * tracing_lseek() should be used as the lseek routine, and
2736 * release must call ftrace_regex_release().
2739 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2740 struct inode *inode, struct file *file)
2742 struct ftrace_iterator *iter;
2743 struct ftrace_hash *hash;
2746 ftrace_ops_init(ops);
2748 if (unlikely(ftrace_disabled))
2751 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2755 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2763 mutex_lock(&ops->regex_lock);
2765 if (flag & FTRACE_ITER_NOTRACE)
2766 hash = ops->notrace_hash;
2768 hash = ops->filter_hash;
2770 if (file->f_mode & FMODE_WRITE) {
2771 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2773 trace_parser_put(&iter->parser);
2780 if ((file->f_mode & FMODE_WRITE) &&
2781 (file->f_flags & O_TRUNC))
2782 ftrace_filter_reset(iter->hash);
2784 if (file->f_mode & FMODE_READ) {
2785 iter->pg = ftrace_pages_start;
2787 ret = seq_open(file, &show_ftrace_seq_ops);
2789 struct seq_file *m = file->private_data;
2793 free_ftrace_hash(iter->hash);
2794 trace_parser_put(&iter->parser);
2798 file->private_data = iter;
2801 mutex_unlock(&ops->regex_lock);
2807 ftrace_filter_open(struct inode *inode, struct file *file)
2809 struct ftrace_ops *ops = inode->i_private;
2811 return ftrace_regex_open(ops,
2812 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2817 ftrace_notrace_open(struct inode *inode, struct file *file)
2819 struct ftrace_ops *ops = inode->i_private;
2821 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
2825 static int ftrace_match(char *str, char *regex, int len, int type)
2832 if (strcmp(str, regex) == 0)
2835 case MATCH_FRONT_ONLY:
2836 if (strncmp(str, regex, len) == 0)
2839 case MATCH_MIDDLE_ONLY:
2840 if (strstr(str, regex))
2843 case MATCH_END_ONLY:
2845 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2854 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2856 struct ftrace_func_entry *entry;
2859 entry = ftrace_lookup_ip(hash, rec->ip);
2861 /* Do nothing if it doesn't exist */
2865 free_hash_entry(hash, entry);
2867 /* Do nothing if it exists */
2871 ret = add_hash_entry(hash, rec->ip);
2877 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2878 char *regex, int len, int type)
2880 char str[KSYM_SYMBOL_LEN];
2883 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2886 /* module lookup requires matching the module */
2887 if (!modname || strcmp(modname, mod))
2890 /* blank search means to match all funcs in the mod */
2895 return ftrace_match(str, regex, len, type);
2899 match_records(struct ftrace_hash *hash, char *buff,
2900 int len, char *mod, int not)
2902 unsigned search_len = 0;
2903 struct ftrace_page *pg;
2904 struct dyn_ftrace *rec;
2905 int type = MATCH_FULL;
2906 char *search = buff;
2911 type = filter_parse_regex(buff, len, &search, ¬);
2912 search_len = strlen(search);
2915 mutex_lock(&ftrace_lock);
2917 if (unlikely(ftrace_disabled))
2920 do_for_each_ftrace_rec(pg, rec) {
2921 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2922 ret = enter_record(hash, rec, not);
2929 } while_for_each_ftrace_rec();
2931 mutex_unlock(&ftrace_lock);
2937 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2939 return match_records(hash, buff, len, NULL, 0);
2943 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2947 /* blank or '*' mean the same */
2948 if (strcmp(buff, "*") == 0)
2951 /* handle the case of 'dont filter this module' */
2952 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2957 return match_records(hash, buff, strlen(buff), mod, not);
2961 * We register the module command as a template to show others how
2962 * to register the a command as well.
2966 ftrace_mod_callback(struct ftrace_hash *hash,
2967 char *func, char *cmd, char *param, int enable)
2973 * cmd == 'mod' because we only registered this func
2974 * for the 'mod' ftrace_func_command.
2975 * But if you register one func with multiple commands,
2976 * you can tell which command was used by the cmd
2980 /* we must have a module name */
2984 mod = strsep(¶m, ":");
2988 ret = ftrace_match_module_records(hash, func, mod);
2997 static struct ftrace_func_command ftrace_mod_cmd = {
2999 .func = ftrace_mod_callback,
3002 static int __init ftrace_mod_cmd_init(void)
3004 return register_ftrace_command(&ftrace_mod_cmd);
3006 core_initcall(ftrace_mod_cmd_init);
3008 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3009 struct ftrace_ops *op, struct pt_regs *pt_regs)
3011 struct ftrace_func_probe *entry;
3012 struct hlist_head *hhd;
3015 key = hash_long(ip, FTRACE_HASH_BITS);
3017 hhd = &ftrace_func_hash[key];
3019 if (hlist_empty(hhd))
3023 * Disable preemption for these calls to prevent a RCU grace
3024 * period. This syncs the hash iteration and freeing of items
3025 * on the hash. rcu_read_lock is too dangerous here.
3027 preempt_disable_notrace();
3028 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3029 if (entry->ip == ip)
3030 entry->ops->func(ip, parent_ip, &entry->data);
3032 preempt_enable_notrace();
3035 static struct ftrace_ops trace_probe_ops __read_mostly =
3037 .func = function_trace_probe_call,
3038 .flags = FTRACE_OPS_FL_INITIALIZED,
3039 INIT_REGEX_LOCK(trace_probe_ops)
3042 static int ftrace_probe_registered;
3044 static void __enable_ftrace_function_probe(void)
3049 if (ftrace_probe_registered) {
3050 /* still need to update the function call sites */
3052 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3056 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3057 struct hlist_head *hhd = &ftrace_func_hash[i];
3061 /* Nothing registered? */
3062 if (i == FTRACE_FUNC_HASHSIZE)
3065 ret = ftrace_startup(&trace_probe_ops, 0);
3067 ftrace_probe_registered = 1;
3070 static void __disable_ftrace_function_probe(void)
3074 if (!ftrace_probe_registered)
3077 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3078 struct hlist_head *hhd = &ftrace_func_hash[i];
3083 /* no more funcs left */
3084 ftrace_shutdown(&trace_probe_ops, 0);
3086 ftrace_probe_registered = 0;
3090 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3092 if (entry->ops->free)
3093 entry->ops->free(entry->ops, entry->ip, &entry->data);
3098 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3101 struct ftrace_func_probe *entry;
3102 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3103 struct ftrace_hash *hash;
3104 struct ftrace_page *pg;
3105 struct dyn_ftrace *rec;
3112 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3113 len = strlen(search);
3115 /* we do not support '!' for function probes */
3119 mutex_lock(&trace_probe_ops.regex_lock);
3121 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3127 if (unlikely(ftrace_disabled)) {
3132 mutex_lock(&ftrace_lock);
3134 do_for_each_ftrace_rec(pg, rec) {
3136 if (!ftrace_match_record(rec, NULL, search, len, type))
3139 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3141 /* If we did not process any, then return error */
3152 * The caller might want to do something special
3153 * for each function we find. We call the callback
3154 * to give the caller an opportunity to do so.
3157 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3158 /* caller does not like this func */
3164 ret = enter_record(hash, rec, 0);
3172 entry->ip = rec->ip;
3174 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3175 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3177 } while_for_each_ftrace_rec();
3179 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3183 __enable_ftrace_function_probe();
3186 mutex_unlock(&ftrace_lock);
3188 mutex_unlock(&trace_probe_ops.regex_lock);
3189 free_ftrace_hash(hash);
3195 PROBE_TEST_FUNC = 1,
3200 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3201 void *data, int flags)
3203 struct ftrace_func_entry *rec_entry;
3204 struct ftrace_func_probe *entry;
3205 struct ftrace_func_probe *p;
3206 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3207 struct list_head free_list;
3208 struct ftrace_hash *hash;
3209 struct hlist_node *tmp;
3210 char str[KSYM_SYMBOL_LEN];
3211 int type = MATCH_FULL;
3215 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3220 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3221 len = strlen(search);
3223 /* we do not support '!' for function probes */
3228 mutex_lock(&trace_probe_ops.regex_lock);
3230 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3232 /* Hmm, should report this somehow */
3235 INIT_LIST_HEAD(&free_list);
3237 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3238 struct hlist_head *hhd = &ftrace_func_hash[i];
3240 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3242 /* break up if statements for readability */
3243 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3246 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3249 /* do this last, since it is the most expensive */
3251 kallsyms_lookup(entry->ip, NULL, NULL,
3253 if (!ftrace_match(str, glob, len, type))
3257 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3258 /* It is possible more than one entry had this ip */
3260 free_hash_entry(hash, rec_entry);
3262 hlist_del_rcu(&entry->node);
3263 list_add(&entry->free_list, &free_list);
3266 mutex_lock(&ftrace_lock);
3267 __disable_ftrace_function_probe();
3269 * Remove after the disable is called. Otherwise, if the last
3270 * probe is removed, a null hash means *all enabled*.
3272 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3273 synchronize_sched();
3274 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3275 list_del(&entry->free_list);
3276 ftrace_free_entry(entry);
3278 mutex_unlock(&ftrace_lock);
3281 mutex_unlock(&trace_probe_ops.regex_lock);
3282 free_ftrace_hash(hash);
3286 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3289 __unregister_ftrace_function_probe(glob, ops, data,
3290 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3294 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3296 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3299 void unregister_ftrace_function_probe_all(char *glob)
3301 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3304 static LIST_HEAD(ftrace_commands);
3305 static DEFINE_MUTEX(ftrace_cmd_mutex);
3308 * Currently we only register ftrace commands from __init, so mark this
3311 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3313 struct ftrace_func_command *p;
3316 mutex_lock(&ftrace_cmd_mutex);
3317 list_for_each_entry(p, &ftrace_commands, list) {
3318 if (strcmp(cmd->name, p->name) == 0) {
3323 list_add(&cmd->list, &ftrace_commands);
3325 mutex_unlock(&ftrace_cmd_mutex);
3331 * Currently we only unregister ftrace commands from __init, so mark
3334 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3336 struct ftrace_func_command *p, *n;
3339 mutex_lock(&ftrace_cmd_mutex);
3340 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3341 if (strcmp(cmd->name, p->name) == 0) {
3343 list_del_init(&p->list);
3348 mutex_unlock(&ftrace_cmd_mutex);
3353 static int ftrace_process_regex(struct ftrace_hash *hash,
3354 char *buff, int len, int enable)
3356 char *func, *command, *next = buff;
3357 struct ftrace_func_command *p;
3360 func = strsep(&next, ":");
3363 ret = ftrace_match_records(hash, func, len);
3373 command = strsep(&next, ":");
3375 mutex_lock(&ftrace_cmd_mutex);
3376 list_for_each_entry(p, &ftrace_commands, list) {
3377 if (strcmp(p->name, command) == 0) {
3378 ret = p->func(hash, func, command, next, enable);
3383 mutex_unlock(&ftrace_cmd_mutex);
3389 ftrace_regex_write(struct file *file, const char __user *ubuf,
3390 size_t cnt, loff_t *ppos, int enable)
3392 struct ftrace_iterator *iter;
3393 struct trace_parser *parser;
3399 if (file->f_mode & FMODE_READ) {
3400 struct seq_file *m = file->private_data;
3403 iter = file->private_data;
3405 if (unlikely(ftrace_disabled))
3408 /* iter->hash is a local copy, so we don't need regex_lock */
3410 parser = &iter->parser;
3411 read = trace_get_user(parser, ubuf, cnt, ppos);
3413 if (read >= 0 && trace_parser_loaded(parser) &&
3414 !trace_parser_cont(parser)) {
3415 ret = ftrace_process_regex(iter->hash, parser->buffer,
3416 parser->idx, enable);
3417 trace_parser_clear(parser);
3428 ftrace_filter_write(struct file *file, const char __user *ubuf,
3429 size_t cnt, loff_t *ppos)
3431 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3435 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3436 size_t cnt, loff_t *ppos)
3438 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3442 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3444 struct ftrace_func_entry *entry;
3446 if (!ftrace_location(ip))
3450 entry = ftrace_lookup_ip(hash, ip);
3453 free_hash_entry(hash, entry);
3457 return add_hash_entry(hash, ip);
3460 static void ftrace_ops_update_code(struct ftrace_ops *ops)
3462 if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
3463 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3467 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3468 unsigned long ip, int remove, int reset, int enable)
3470 struct ftrace_hash **orig_hash;
3471 struct ftrace_hash *hash;
3474 if (unlikely(ftrace_disabled))
3477 mutex_lock(&ops->regex_lock);
3480 orig_hash = &ops->filter_hash;
3482 orig_hash = &ops->notrace_hash;
3484 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3487 goto out_regex_unlock;
3491 ftrace_filter_reset(hash);
3492 if (buf && !ftrace_match_records(hash, buf, len)) {
3494 goto out_regex_unlock;
3497 ret = ftrace_match_addr(hash, ip, remove);
3499 goto out_regex_unlock;
3502 mutex_lock(&ftrace_lock);
3503 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3505 ftrace_ops_update_code(ops);
3507 mutex_unlock(&ftrace_lock);
3510 mutex_unlock(&ops->regex_lock);
3512 free_ftrace_hash(hash);
3517 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3518 int reset, int enable)
3520 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3524 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3525 * @ops - the ops to set the filter with
3526 * @ip - the address to add to or remove from the filter.
3527 * @remove - non zero to remove the ip from the filter
3528 * @reset - non zero to reset all filters before applying this filter.
3530 * Filters denote which functions should be enabled when tracing is enabled
3531 * If @ip is NULL, it failes to update filter.
3533 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3534 int remove, int reset)
3536 ftrace_ops_init(ops);
3537 return ftrace_set_addr(ops, ip, remove, reset, 1);
3539 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3542 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3543 int reset, int enable)
3545 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3549 * ftrace_set_filter - set a function to filter on in ftrace
3550 * @ops - the ops to set the filter with
3551 * @buf - the string that holds the function filter text.
3552 * @len - the length of the string.
3553 * @reset - non zero to reset all filters before applying this filter.
3555 * Filters denote which functions should be enabled when tracing is enabled.
3556 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3558 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3561 ftrace_ops_init(ops);
3562 return ftrace_set_regex(ops, buf, len, reset, 1);
3564 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3567 * ftrace_set_notrace - set a function to not trace in ftrace
3568 * @ops - the ops to set the notrace filter with
3569 * @buf - the string that holds the function notrace text.
3570 * @len - the length of the string.
3571 * @reset - non zero to reset all filters before applying this filter.
3573 * Notrace Filters denote which functions should not be enabled when tracing
3574 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3577 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3580 ftrace_ops_init(ops);
3581 return ftrace_set_regex(ops, buf, len, reset, 0);
3583 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3585 * ftrace_set_global_filter - set a function to filter on with global tracers
3586 * @buf - the string that holds the function filter text.
3587 * @len - the length of the string.
3588 * @reset - non zero to reset all filters before applying this filter.
3590 * Filters denote which functions should be enabled when tracing is enabled.
3591 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3593 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3595 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3597 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3600 * ftrace_set_global_notrace - set a function to not trace with global tracers
3601 * @buf - the string that holds the function notrace text.
3602 * @len - the length of the string.
3603 * @reset - non zero to reset all filters before applying this filter.
3605 * Notrace Filters denote which functions should not be enabled when tracing
3606 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3609 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3611 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3613 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3616 * command line interface to allow users to set filters on boot up.
3618 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3619 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3620 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3622 /* Used by function selftest to not test if filter is set */
3623 bool ftrace_filter_param __initdata;
3625 static int __init set_ftrace_notrace(char *str)
3627 ftrace_filter_param = true;
3628 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3631 __setup("ftrace_notrace=", set_ftrace_notrace);
3633 static int __init set_ftrace_filter(char *str)
3635 ftrace_filter_param = true;
3636 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3639 __setup("ftrace_filter=", set_ftrace_filter);
3641 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3642 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3643 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
3645 static int __init set_graph_function(char *str)
3647 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3650 __setup("ftrace_graph_filter=", set_graph_function);
3652 static void __init set_ftrace_early_graph(char *buf)
3658 func = strsep(&buf, ",");
3659 /* we allow only one expression at a time */
3660 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3661 FTRACE_GRAPH_MAX_FUNCS, func);
3663 printk(KERN_DEBUG "ftrace: function %s not "
3664 "traceable\n", func);
3667 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3670 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3674 ftrace_ops_init(ops);
3677 func = strsep(&buf, ",");
3678 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3682 static void __init set_ftrace_early_filters(void)
3684 if (ftrace_filter_buf[0])
3685 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3686 if (ftrace_notrace_buf[0])
3687 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3688 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3689 if (ftrace_graph_buf[0])
3690 set_ftrace_early_graph(ftrace_graph_buf);
3691 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3694 int ftrace_regex_release(struct inode *inode, struct file *file)
3696 struct seq_file *m = (struct seq_file *)file->private_data;
3697 struct ftrace_iterator *iter;
3698 struct ftrace_hash **orig_hash;
3699 struct trace_parser *parser;
3703 if (file->f_mode & FMODE_READ) {
3705 seq_release(inode, file);
3707 iter = file->private_data;
3709 parser = &iter->parser;
3710 if (trace_parser_loaded(parser)) {
3711 parser->buffer[parser->idx] = 0;
3712 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3715 trace_parser_put(parser);
3717 mutex_lock(&iter->ops->regex_lock);
3719 if (file->f_mode & FMODE_WRITE) {
3720 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3723 orig_hash = &iter->ops->filter_hash;
3725 orig_hash = &iter->ops->notrace_hash;
3727 mutex_lock(&ftrace_lock);
3728 ret = ftrace_hash_move(iter->ops, filter_hash,
3729 orig_hash, iter->hash);
3731 ftrace_ops_update_code(iter->ops);
3733 mutex_unlock(&ftrace_lock);
3736 mutex_unlock(&iter->ops->regex_lock);
3737 free_ftrace_hash(iter->hash);
3743 static const struct file_operations ftrace_avail_fops = {
3744 .open = ftrace_avail_open,
3746 .llseek = seq_lseek,
3747 .release = seq_release_private,
3750 static const struct file_operations ftrace_enabled_fops = {
3751 .open = ftrace_enabled_open,
3753 .llseek = seq_lseek,
3754 .release = seq_release_private,
3757 static const struct file_operations ftrace_filter_fops = {
3758 .open = ftrace_filter_open,
3760 .write = ftrace_filter_write,
3761 .llseek = tracing_lseek,
3762 .release = ftrace_regex_release,
3765 static const struct file_operations ftrace_notrace_fops = {
3766 .open = ftrace_notrace_open,
3768 .write = ftrace_notrace_write,
3769 .llseek = tracing_lseek,
3770 .release = ftrace_regex_release,
3773 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3775 static DEFINE_MUTEX(graph_lock);
3777 int ftrace_graph_count;
3778 int ftrace_graph_notrace_count;
3779 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3780 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3782 struct ftrace_graph_data {
3783 unsigned long *table;
3786 const struct seq_operations *seq_ops;
3790 __g_next(struct seq_file *m, loff_t *pos)
3792 struct ftrace_graph_data *fgd = m->private;
3794 if (*pos >= *fgd->count)
3796 return &fgd->table[*pos];
3800 g_next(struct seq_file *m, void *v, loff_t *pos)
3803 return __g_next(m, pos);
3806 static void *g_start(struct seq_file *m, loff_t *pos)
3808 struct ftrace_graph_data *fgd = m->private;
3810 mutex_lock(&graph_lock);
3812 /* Nothing, tell g_show to print all functions are enabled */
3813 if (!*fgd->count && !*pos)
3816 return __g_next(m, pos);
3819 static void g_stop(struct seq_file *m, void *p)
3821 mutex_unlock(&graph_lock);
3824 static int g_show(struct seq_file *m, void *v)
3826 unsigned long *ptr = v;
3831 if (ptr == (unsigned long *)1) {
3832 seq_printf(m, "#### all functions enabled ####\n");
3836 seq_printf(m, "%ps\n", (void *)*ptr);
3841 static const struct seq_operations ftrace_graph_seq_ops = {
3849 __ftrace_graph_open(struct inode *inode, struct file *file,
3850 struct ftrace_graph_data *fgd)
3854 mutex_lock(&graph_lock);
3855 if ((file->f_mode & FMODE_WRITE) &&
3856 (file->f_flags & O_TRUNC)) {
3858 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
3860 mutex_unlock(&graph_lock);
3862 if (file->f_mode & FMODE_READ) {
3863 ret = seq_open(file, fgd->seq_ops);
3865 struct seq_file *m = file->private_data;
3869 file->private_data = fgd;
3875 ftrace_graph_open(struct inode *inode, struct file *file)
3877 struct ftrace_graph_data *fgd;
3879 if (unlikely(ftrace_disabled))
3882 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3886 fgd->table = ftrace_graph_funcs;
3887 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3888 fgd->count = &ftrace_graph_count;
3889 fgd->seq_ops = &ftrace_graph_seq_ops;
3891 return __ftrace_graph_open(inode, file, fgd);
3895 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
3897 struct ftrace_graph_data *fgd;
3899 if (unlikely(ftrace_disabled))
3902 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3906 fgd->table = ftrace_graph_notrace_funcs;
3907 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3908 fgd->count = &ftrace_graph_notrace_count;
3909 fgd->seq_ops = &ftrace_graph_seq_ops;
3911 return __ftrace_graph_open(inode, file, fgd);
3915 ftrace_graph_release(struct inode *inode, struct file *file)
3917 if (file->f_mode & FMODE_READ) {
3918 struct seq_file *m = file->private_data;
3921 seq_release(inode, file);
3923 kfree(file->private_data);
3930 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
3932 struct dyn_ftrace *rec;
3933 struct ftrace_page *pg;
3942 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3943 if (!not && *idx >= size)
3946 search_len = strlen(search);
3948 mutex_lock(&ftrace_lock);
3950 if (unlikely(ftrace_disabled)) {
3951 mutex_unlock(&ftrace_lock);
3955 do_for_each_ftrace_rec(pg, rec) {
3957 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3958 /* if it is in the array */
3960 for (i = 0; i < *idx; i++) {
3961 if (array[i] == rec->ip) {
3970 array[(*idx)++] = rec->ip;
3976 array[i] = array[--(*idx)];
3982 } while_for_each_ftrace_rec();
3984 mutex_unlock(&ftrace_lock);
3993 ftrace_graph_write(struct file *file, const char __user *ubuf,
3994 size_t cnt, loff_t *ppos)
3996 struct trace_parser parser;
3997 ssize_t read, ret = 0;
3998 struct ftrace_graph_data *fgd = file->private_data;
4003 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4006 read = trace_get_user(&parser, ubuf, cnt, ppos);
4008 if (read >= 0 && trace_parser_loaded((&parser))) {
4009 parser.buffer[parser.idx] = 0;
4011 mutex_lock(&graph_lock);
4013 /* we allow only one expression at a time */
4014 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4017 mutex_unlock(&graph_lock);
4023 trace_parser_put(&parser);
4028 static const struct file_operations ftrace_graph_fops = {
4029 .open = ftrace_graph_open,
4031 .write = ftrace_graph_write,
4032 .llseek = tracing_lseek,
4033 .release = ftrace_graph_release,
4036 static const struct file_operations ftrace_graph_notrace_fops = {
4037 .open = ftrace_graph_notrace_open,
4039 .write = ftrace_graph_write,
4040 .llseek = tracing_lseek,
4041 .release = ftrace_graph_release,
4043 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4045 void ftrace_create_filter_files(struct ftrace_ops *ops,
4046 struct dentry *parent)
4049 trace_create_file("set_ftrace_filter", 0644, parent,
4050 ops, &ftrace_filter_fops);
4052 trace_create_file("set_ftrace_notrace", 0644, parent,
4053 ops, &ftrace_notrace_fops);
4057 * The name "destroy_filter_files" is really a misnomer. Although
4058 * in the future, it may actualy delete the files, but this is
4059 * really intended to make sure the ops passed in are disabled
4060 * and that when this function returns, the caller is free to
4063 * The "destroy" name is only to match the "create" name that this
4064 * should be paired with.
4066 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4068 mutex_lock(&ftrace_lock);
4069 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4070 ftrace_shutdown(ops, 0);
4071 ops->flags |= FTRACE_OPS_FL_DELETED;
4072 mutex_unlock(&ftrace_lock);
4075 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
4078 trace_create_file("available_filter_functions", 0444,
4079 d_tracer, NULL, &ftrace_avail_fops);
4081 trace_create_file("enabled_functions", 0444,
4082 d_tracer, NULL, &ftrace_enabled_fops);
4084 ftrace_create_filter_files(&global_ops, d_tracer);
4086 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4087 trace_create_file("set_graph_function", 0444, d_tracer,
4089 &ftrace_graph_fops);
4090 trace_create_file("set_graph_notrace", 0444, d_tracer,
4092 &ftrace_graph_notrace_fops);
4093 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4098 static int ftrace_cmp_ips(const void *a, const void *b)
4100 const unsigned long *ipa = a;
4101 const unsigned long *ipb = b;
4110 static void ftrace_swap_ips(void *a, void *b, int size)
4112 unsigned long *ipa = a;
4113 unsigned long *ipb = b;
4121 static int ftrace_process_locs(struct module *mod,
4122 unsigned long *start,
4125 struct ftrace_page *start_pg;
4126 struct ftrace_page *pg;
4127 struct dyn_ftrace *rec;
4128 unsigned long count;
4131 unsigned long flags = 0; /* Shut up gcc */
4134 count = end - start;
4139 sort(start, count, sizeof(*start),
4140 ftrace_cmp_ips, ftrace_swap_ips);
4142 start_pg = ftrace_allocate_pages(count);
4146 mutex_lock(&ftrace_lock);
4149 * Core and each module needs their own pages, as
4150 * modules will free them when they are removed.
4151 * Force a new page to be allocated for modules.
4154 WARN_ON(ftrace_pages || ftrace_pages_start);
4155 /* First initialization */
4156 ftrace_pages = ftrace_pages_start = start_pg;
4161 if (WARN_ON(ftrace_pages->next)) {
4162 /* Hmm, we have free pages? */
4163 while (ftrace_pages->next)
4164 ftrace_pages = ftrace_pages->next;
4167 ftrace_pages->next = start_pg;
4173 addr = ftrace_call_adjust(*p++);
4175 * Some architecture linkers will pad between
4176 * the different mcount_loc sections of different
4177 * object files to satisfy alignments.
4178 * Skip any NULL pointers.
4183 if (pg->index == pg->size) {
4184 /* We should have allocated enough */
4185 if (WARN_ON(!pg->next))
4190 rec = &pg->records[pg->index++];
4194 /* We should have used all pages */
4197 /* Assign the last page to ftrace_pages */
4201 * We only need to disable interrupts on start up
4202 * because we are modifying code that an interrupt
4203 * may execute, and the modification is not atomic.
4204 * But for modules, nothing runs the code we modify
4205 * until we are finished with it, and there's no
4206 * reason to cause large interrupt latencies while we do it.
4209 local_irq_save(flags);
4210 ftrace_update_code(mod, start_pg);
4212 local_irq_restore(flags);
4215 mutex_unlock(&ftrace_lock);
4220 #ifdef CONFIG_MODULES
4222 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4224 void ftrace_release_mod(struct module *mod)
4226 struct dyn_ftrace *rec;
4227 struct ftrace_page **last_pg;
4228 struct ftrace_page *pg;
4231 mutex_lock(&ftrace_lock);
4233 if (ftrace_disabled)
4237 * Each module has its own ftrace_pages, remove
4238 * them from the list.
4240 last_pg = &ftrace_pages_start;
4241 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4242 rec = &pg->records[0];
4243 if (within_module_core(rec->ip, mod)) {
4245 * As core pages are first, the first
4246 * page should never be a module page.
4248 if (WARN_ON(pg == ftrace_pages_start))
4251 /* Check if we are deleting the last page */
4252 if (pg == ftrace_pages)
4253 ftrace_pages = next_to_ftrace_page(last_pg);
4255 *last_pg = pg->next;
4256 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4257 free_pages((unsigned long)pg->records, order);
4260 last_pg = &pg->next;
4263 mutex_unlock(&ftrace_lock);
4266 static void ftrace_init_module(struct module *mod,
4267 unsigned long *start, unsigned long *end)
4269 if (ftrace_disabled || start == end)
4271 ftrace_process_locs(mod, start, end);
4274 static int ftrace_module_notify_enter(struct notifier_block *self,
4275 unsigned long val, void *data)
4277 struct module *mod = data;
4279 if (val == MODULE_STATE_COMING)
4280 ftrace_init_module(mod, mod->ftrace_callsites,
4281 mod->ftrace_callsites +
4282 mod->num_ftrace_callsites);
4286 static int ftrace_module_notify_exit(struct notifier_block *self,
4287 unsigned long val, void *data)
4289 struct module *mod = data;
4291 if (val == MODULE_STATE_GOING)
4292 ftrace_release_mod(mod);
4297 static int ftrace_module_notify_enter(struct notifier_block *self,
4298 unsigned long val, void *data)
4302 static int ftrace_module_notify_exit(struct notifier_block *self,
4303 unsigned long val, void *data)
4307 #endif /* CONFIG_MODULES */
4309 struct notifier_block ftrace_module_enter_nb = {
4310 .notifier_call = ftrace_module_notify_enter,
4311 .priority = INT_MAX, /* Run before anything that can use kprobes */
4314 struct notifier_block ftrace_module_exit_nb = {
4315 .notifier_call = ftrace_module_notify_exit,
4316 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4319 void __init ftrace_init(void)
4321 extern unsigned long __start_mcount_loc[];
4322 extern unsigned long __stop_mcount_loc[];
4323 unsigned long count, flags;
4326 local_irq_save(flags);
4327 ret = ftrace_dyn_arch_init();
4328 local_irq_restore(flags);
4332 count = __stop_mcount_loc - __start_mcount_loc;
4334 pr_info("ftrace: No functions to be traced?\n");
4338 pr_info("ftrace: allocating %ld entries in %ld pages\n",
4339 count, count / ENTRIES_PER_PAGE + 1);
4341 last_ftrace_enabled = ftrace_enabled = 1;
4343 ret = ftrace_process_locs(NULL,
4347 ret = register_module_notifier(&ftrace_module_enter_nb);
4349 pr_warning("Failed to register trace ftrace module enter notifier\n");
4351 ret = register_module_notifier(&ftrace_module_exit_nb);
4353 pr_warning("Failed to register trace ftrace module exit notifier\n");
4355 set_ftrace_early_filters();
4359 ftrace_disabled = 1;
4364 static struct ftrace_ops global_ops = {
4365 .func = ftrace_stub,
4366 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4367 INIT_REGEX_LOCK(global_ops)
4370 static int __init ftrace_nodyn_init(void)
4375 core_initcall(ftrace_nodyn_init);
4377 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4378 static inline void ftrace_startup_enable(int command) { }
4379 /* Keep as macros so we do not need to define the commands */
4380 # define ftrace_startup(ops, command) \
4382 int ___ret = __register_ftrace_function(ops); \
4384 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4387 # define ftrace_shutdown(ops, command) \
4389 int ___ret = __unregister_ftrace_function(ops); \
4391 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
4395 # define ftrace_startup_sysctl() do { } while (0)
4396 # define ftrace_shutdown_sysctl() do { } while (0)
4399 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4404 #endif /* CONFIG_DYNAMIC_FTRACE */
4406 __init void ftrace_init_global_array_ops(struct trace_array *tr)
4408 tr->ops = &global_ops;
4409 tr->ops->private = tr;
4412 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
4414 /* If we filter on pids, update to use the pid function */
4415 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
4416 if (WARN_ON(tr->ops->func != ftrace_stub))
4417 printk("ftrace ops had %pS for function\n",
4419 /* Only the top level instance does pid tracing */
4420 if (!list_empty(&ftrace_pids)) {
4421 set_ftrace_pid_function(func);
4422 func = ftrace_pid_func;
4425 tr->ops->func = func;
4426 tr->ops->private = tr;
4429 void ftrace_reset_array_ops(struct trace_array *tr)
4431 tr->ops->func = ftrace_stub;
4435 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4436 struct ftrace_ops *op, struct pt_regs *regs)
4438 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4442 * Some of the ops may be dynamically allocated,
4443 * they must be freed after a synchronize_sched().
4445 preempt_disable_notrace();
4446 trace_recursion_set(TRACE_CONTROL_BIT);
4449 * Control funcs (perf) uses RCU. Only trace if
4450 * RCU is currently active.
4452 if (!rcu_is_watching())
4455 do_for_each_ftrace_op(op, ftrace_control_list) {
4456 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4457 !ftrace_function_local_disabled(op) &&
4458 ftrace_ops_test(op, ip, regs))
4459 op->func(ip, parent_ip, op, regs);
4460 } while_for_each_ftrace_op(op);
4462 trace_recursion_clear(TRACE_CONTROL_BIT);
4463 preempt_enable_notrace();
4466 static struct ftrace_ops control_ops = {
4467 .func = ftrace_ops_control_func,
4468 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4469 INIT_REGEX_LOCK(control_ops)
4473 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4474 struct ftrace_ops *ignored, struct pt_regs *regs)
4476 struct ftrace_ops *op;
4479 if (function_trace_stop)
4482 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4487 * Some of the ops may be dynamically allocated,
4488 * they must be freed after a synchronize_sched().
4490 preempt_disable_notrace();
4491 do_for_each_ftrace_op(op, ftrace_ops_list) {
4492 if (ftrace_ops_test(op, ip, regs)) {
4493 if (WARN_ON(!op->func)) {
4494 function_trace_stop = 1;
4495 printk("op=%p %pS\n", op, op);
4498 op->func(ip, parent_ip, op, regs);
4500 } while_for_each_ftrace_op(op);
4502 preempt_enable_notrace();
4503 trace_clear_recursion(bit);
4507 * Some archs only support passing ip and parent_ip. Even though
4508 * the list function ignores the op parameter, we do not want any
4509 * C side effects, where a function is called without the caller
4510 * sending a third parameter.
4511 * Archs are to support both the regs and ftrace_ops at the same time.
4512 * If they support ftrace_ops, it is assumed they support regs.
4513 * If call backs want to use regs, they must either check for regs
4514 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4515 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4516 * An architecture can pass partial regs with ftrace_ops and still
4517 * set the ARCH_SUPPORT_FTARCE_OPS.
4519 #if ARCH_SUPPORTS_FTRACE_OPS
4520 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4521 struct ftrace_ops *op, struct pt_regs *regs)
4523 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4526 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4528 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4532 static void clear_ftrace_swapper(void)
4534 struct task_struct *p;
4538 for_each_online_cpu(cpu) {
4540 clear_tsk_trace_trace(p);
4545 static void set_ftrace_swapper(void)
4547 struct task_struct *p;
4551 for_each_online_cpu(cpu) {
4553 set_tsk_trace_trace(p);
4558 static void clear_ftrace_pid(struct pid *pid)
4560 struct task_struct *p;
4563 do_each_pid_task(pid, PIDTYPE_PID, p) {
4564 clear_tsk_trace_trace(p);
4565 } while_each_pid_task(pid, PIDTYPE_PID, p);
4571 static void set_ftrace_pid(struct pid *pid)
4573 struct task_struct *p;
4576 do_each_pid_task(pid, PIDTYPE_PID, p) {
4577 set_tsk_trace_trace(p);
4578 } while_each_pid_task(pid, PIDTYPE_PID, p);
4582 static void clear_ftrace_pid_task(struct pid *pid)
4584 if (pid == ftrace_swapper_pid)
4585 clear_ftrace_swapper();
4587 clear_ftrace_pid(pid);
4590 static void set_ftrace_pid_task(struct pid *pid)
4592 if (pid == ftrace_swapper_pid)
4593 set_ftrace_swapper();
4595 set_ftrace_pid(pid);
4598 static int ftrace_pid_add(int p)
4601 struct ftrace_pid *fpid;
4604 mutex_lock(&ftrace_lock);
4607 pid = ftrace_swapper_pid;
4609 pid = find_get_pid(p);
4616 list_for_each_entry(fpid, &ftrace_pids, list)
4617 if (fpid->pid == pid)
4622 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4626 list_add(&fpid->list, &ftrace_pids);
4629 set_ftrace_pid_task(pid);
4631 ftrace_update_pid_func();
4632 ftrace_startup_enable(0);
4634 mutex_unlock(&ftrace_lock);
4638 if (pid != ftrace_swapper_pid)
4642 mutex_unlock(&ftrace_lock);
4646 static void ftrace_pid_reset(void)
4648 struct ftrace_pid *fpid, *safe;
4650 mutex_lock(&ftrace_lock);
4651 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4652 struct pid *pid = fpid->pid;
4654 clear_ftrace_pid_task(pid);
4656 list_del(&fpid->list);
4660 ftrace_update_pid_func();
4661 ftrace_startup_enable(0);
4663 mutex_unlock(&ftrace_lock);
4666 static void *fpid_start(struct seq_file *m, loff_t *pos)
4668 mutex_lock(&ftrace_lock);
4670 if (list_empty(&ftrace_pids) && (!*pos))
4673 return seq_list_start(&ftrace_pids, *pos);
4676 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4681 return seq_list_next(v, &ftrace_pids, pos);
4684 static void fpid_stop(struct seq_file *m, void *p)
4686 mutex_unlock(&ftrace_lock);
4689 static int fpid_show(struct seq_file *m, void *v)
4691 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4693 if (v == (void *)1) {
4694 seq_printf(m, "no pid\n");
4698 if (fpid->pid == ftrace_swapper_pid)
4699 seq_printf(m, "swapper tasks\n");
4701 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4706 static const struct seq_operations ftrace_pid_sops = {
4707 .start = fpid_start,
4714 ftrace_pid_open(struct inode *inode, struct file *file)
4718 if ((file->f_mode & FMODE_WRITE) &&
4719 (file->f_flags & O_TRUNC))
4722 if (file->f_mode & FMODE_READ)
4723 ret = seq_open(file, &ftrace_pid_sops);
4729 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4730 size_t cnt, loff_t *ppos)
4736 if (cnt >= sizeof(buf))
4739 if (copy_from_user(&buf, ubuf, cnt))
4745 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4746 * to clean the filter quietly.
4748 tmp = strstrip(buf);
4749 if (strlen(tmp) == 0)
4752 ret = kstrtol(tmp, 10, &val);
4756 ret = ftrace_pid_add(val);
4758 return ret ? ret : cnt;
4762 ftrace_pid_release(struct inode *inode, struct file *file)
4764 if (file->f_mode & FMODE_READ)
4765 seq_release(inode, file);
4770 static const struct file_operations ftrace_pid_fops = {
4771 .open = ftrace_pid_open,
4772 .write = ftrace_pid_write,
4774 .llseek = tracing_lseek,
4775 .release = ftrace_pid_release,
4778 static __init int ftrace_init_debugfs(void)
4780 struct dentry *d_tracer;
4782 d_tracer = tracing_init_dentry();
4786 ftrace_init_dyn_debugfs(d_tracer);
4788 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4789 NULL, &ftrace_pid_fops);
4791 ftrace_profile_debugfs(d_tracer);
4795 fs_initcall(ftrace_init_debugfs);
4798 * ftrace_kill - kill ftrace
4800 * This function should be used by panic code. It stops ftrace
4801 * but in a not so nice way. If you need to simply kill ftrace
4802 * from a non-atomic section, use ftrace_kill.
4804 void ftrace_kill(void)
4806 ftrace_disabled = 1;
4808 clear_ftrace_function();
4812 * Test if ftrace is dead or not.
4814 int ftrace_is_dead(void)
4816 return ftrace_disabled;
4820 * register_ftrace_function - register a function for profiling
4821 * @ops - ops structure that holds the function for profiling.
4823 * Register a function to be called by all functions in the
4826 * Note: @ops->func and all the functions it calls must be labeled
4827 * with "notrace", otherwise it will go into a
4830 int register_ftrace_function(struct ftrace_ops *ops)
4834 ftrace_ops_init(ops);
4836 mutex_lock(&ftrace_lock);
4838 ret = ftrace_startup(ops, 0);
4840 mutex_unlock(&ftrace_lock);
4844 EXPORT_SYMBOL_GPL(register_ftrace_function);
4847 * unregister_ftrace_function - unregister a function for profiling.
4848 * @ops - ops structure that holds the function to unregister
4850 * Unregister a function that was added to be called by ftrace profiling.
4852 int unregister_ftrace_function(struct ftrace_ops *ops)
4856 mutex_lock(&ftrace_lock);
4857 ret = ftrace_shutdown(ops, 0);
4858 mutex_unlock(&ftrace_lock);
4862 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4865 ftrace_enable_sysctl(struct ctl_table *table, int write,
4866 void __user *buffer, size_t *lenp,
4871 mutex_lock(&ftrace_lock);
4873 if (unlikely(ftrace_disabled))
4876 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4878 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4881 last_ftrace_enabled = !!ftrace_enabled;
4883 if (ftrace_enabled) {
4885 ftrace_startup_sysctl();
4887 /* we are starting ftrace again */
4888 if (ftrace_ops_list != &ftrace_list_end)
4889 update_ftrace_function();
4892 /* stopping ftrace calls (just send to ftrace_stub) */
4893 ftrace_trace_function = ftrace_stub;
4895 ftrace_shutdown_sysctl();
4899 mutex_unlock(&ftrace_lock);
4903 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4905 static int ftrace_graph_active;
4907 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4912 /* The callbacks that hook a function */
4913 trace_func_graph_ret_t ftrace_graph_return =
4914 (trace_func_graph_ret_t)ftrace_stub;
4915 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4916 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
4918 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4919 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4923 unsigned long flags;
4924 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4925 struct task_struct *g, *t;
4927 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4928 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4929 * sizeof(struct ftrace_ret_stack),
4931 if (!ret_stack_list[i]) {
4939 read_lock_irqsave(&tasklist_lock, flags);
4940 do_each_thread(g, t) {
4946 if (t->ret_stack == NULL) {
4947 atomic_set(&t->tracing_graph_pause, 0);
4948 atomic_set(&t->trace_overrun, 0);
4949 t->curr_ret_stack = -1;
4950 /* Make sure the tasks see the -1 first: */
4952 t->ret_stack = ret_stack_list[start++];
4954 } while_each_thread(g, t);
4957 read_unlock_irqrestore(&tasklist_lock, flags);
4959 for (i = start; i < end; i++)
4960 kfree(ret_stack_list[i]);
4965 ftrace_graph_probe_sched_switch(void *ignore,
4966 struct task_struct *prev, struct task_struct *next)
4968 unsigned long long timestamp;
4972 * Does the user want to count the time a function was asleep.
4973 * If so, do not update the time stamps.
4975 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4978 timestamp = trace_clock_local();
4980 prev->ftrace_timestamp = timestamp;
4982 /* only process tasks that we timestamped */
4983 if (!next->ftrace_timestamp)
4987 * Update all the counters in next to make up for the
4988 * time next was sleeping.
4990 timestamp -= next->ftrace_timestamp;
4992 for (index = next->curr_ret_stack; index >= 0; index--)
4993 next->ret_stack[index].calltime += timestamp;
4996 /* Allocate a return stack for each task */
4997 static int start_graph_tracing(void)
4999 struct ftrace_ret_stack **ret_stack_list;
5002 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5003 sizeof(struct ftrace_ret_stack *),
5006 if (!ret_stack_list)
5009 /* The cpu_boot init_task->ret_stack will never be freed */
5010 for_each_online_cpu(cpu) {
5011 if (!idle_task(cpu)->ret_stack)
5012 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5016 ret = alloc_retstack_tasklist(ret_stack_list);
5017 } while (ret == -EAGAIN);
5020 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5022 pr_info("ftrace_graph: Couldn't activate tracepoint"
5023 " probe to kernel_sched_switch\n");
5026 kfree(ret_stack_list);
5031 * Hibernation protection.
5032 * The state of the current task is too much unstable during
5033 * suspend/restore to disk. We want to protect against that.
5036 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5040 case PM_HIBERNATION_PREPARE:
5041 pause_graph_tracing();
5044 case PM_POST_HIBERNATION:
5045 unpause_graph_tracing();
5051 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5053 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5055 return __ftrace_graph_entry(trace);
5059 * The function graph tracer should only trace the functions defined
5060 * by set_ftrace_filter and set_ftrace_notrace. If another function
5061 * tracer ops is registered, the graph tracer requires testing the
5062 * function against the global ops, and not just trace any function
5063 * that any ftrace_ops registered.
5065 static void update_function_graph_func(void)
5067 if (ftrace_ops_list == &ftrace_list_end ||
5068 (ftrace_ops_list == &global_ops &&
5069 global_ops.next == &ftrace_list_end))
5070 ftrace_graph_entry = __ftrace_graph_entry;
5072 ftrace_graph_entry = ftrace_graph_entry_test;
5075 static struct notifier_block ftrace_suspend_notifier = {
5076 .notifier_call = ftrace_suspend_notifier_call,
5079 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5080 trace_func_graph_ent_t entryfunc)
5084 mutex_lock(&ftrace_lock);
5086 /* we currently allow only one tracer registered at a time */
5087 if (ftrace_graph_active) {
5092 register_pm_notifier(&ftrace_suspend_notifier);
5094 ftrace_graph_active++;
5095 ret = start_graph_tracing();
5097 ftrace_graph_active--;
5101 ftrace_graph_return = retfunc;
5104 * Update the indirect function to the entryfunc, and the
5105 * function that gets called to the entry_test first. Then
5106 * call the update fgraph entry function to determine if
5107 * the entryfunc should be called directly or not.
5109 __ftrace_graph_entry = entryfunc;
5110 ftrace_graph_entry = ftrace_graph_entry_test;
5111 update_function_graph_func();
5113 /* Function graph doesn't use the .func field of global_ops */
5114 global_ops.flags |= FTRACE_OPS_FL_STUB;
5116 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
5119 mutex_unlock(&ftrace_lock);
5123 void unregister_ftrace_graph(void)
5125 mutex_lock(&ftrace_lock);
5127 if (unlikely(!ftrace_graph_active))
5130 ftrace_graph_active--;
5131 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5132 ftrace_graph_entry = ftrace_graph_entry_stub;
5133 __ftrace_graph_entry = ftrace_graph_entry_stub;
5134 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
5135 global_ops.flags &= ~FTRACE_OPS_FL_STUB;
5136 unregister_pm_notifier(&ftrace_suspend_notifier);
5137 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5140 mutex_unlock(&ftrace_lock);
5143 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5146 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5148 atomic_set(&t->tracing_graph_pause, 0);
5149 atomic_set(&t->trace_overrun, 0);
5150 t->ftrace_timestamp = 0;
5151 /* make curr_ret_stack visible before we add the ret_stack */
5153 t->ret_stack = ret_stack;
5157 * Allocate a return stack for the idle task. May be the first
5158 * time through, or it may be done by CPU hotplug online.
5160 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5162 t->curr_ret_stack = -1;
5164 * The idle task has no parent, it either has its own
5165 * stack or no stack at all.
5168 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5170 if (ftrace_graph_active) {
5171 struct ftrace_ret_stack *ret_stack;
5173 ret_stack = per_cpu(idle_ret_stack, cpu);
5175 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5176 * sizeof(struct ftrace_ret_stack),
5180 per_cpu(idle_ret_stack, cpu) = ret_stack;
5182 graph_init_task(t, ret_stack);
5186 /* Allocate a return stack for newly created task */
5187 void ftrace_graph_init_task(struct task_struct *t)
5189 /* Make sure we do not use the parent ret_stack */
5190 t->ret_stack = NULL;
5191 t->curr_ret_stack = -1;
5193 if (ftrace_graph_active) {
5194 struct ftrace_ret_stack *ret_stack;
5196 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5197 * sizeof(struct ftrace_ret_stack),
5201 graph_init_task(t, ret_stack);
5205 void ftrace_graph_exit_task(struct task_struct *t)
5207 struct ftrace_ret_stack *ret_stack = t->ret_stack;
5209 t->ret_stack = NULL;
5210 /* NULL must become visible to IRQs before we free it: */
5216 void ftrace_graph_stop(void)