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 static struct ftrace_ops *removed_ops;
1047 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1048 # error Dynamic ftrace depends on MCOUNT_RECORD
1051 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1053 struct ftrace_func_probe {
1054 struct hlist_node node;
1055 struct ftrace_probe_ops *ops;
1056 unsigned long flags;
1059 struct list_head free_list;
1062 struct ftrace_func_entry {
1063 struct hlist_node hlist;
1067 struct ftrace_hash {
1068 unsigned long size_bits;
1069 struct hlist_head *buckets;
1070 unsigned long count;
1071 struct rcu_head rcu;
1075 * We make these constant because no one should touch them,
1076 * but they are used as the default "empty hash", to avoid allocating
1077 * it all the time. These are in a read only section such that if
1078 * anyone does try to modify it, it will cause an exception.
1080 static const struct hlist_head empty_buckets[1];
1081 static const struct ftrace_hash empty_hash = {
1082 .buckets = (struct hlist_head *)empty_buckets,
1084 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1086 static struct ftrace_ops global_ops = {
1087 .func = ftrace_stub,
1088 .notrace_hash = EMPTY_HASH,
1089 .filter_hash = EMPTY_HASH,
1090 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1091 INIT_REGEX_LOCK(global_ops)
1094 struct ftrace_page {
1095 struct ftrace_page *next;
1096 struct dyn_ftrace *records;
1101 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1102 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1104 /* estimate from running different kernels */
1105 #define NR_TO_INIT 10000
1107 static struct ftrace_page *ftrace_pages_start;
1108 static struct ftrace_page *ftrace_pages;
1110 static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1112 return !hash || !hash->count;
1115 static struct ftrace_func_entry *
1116 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1119 struct ftrace_func_entry *entry;
1120 struct hlist_head *hhd;
1122 if (ftrace_hash_empty(hash))
1125 if (hash->size_bits > 0)
1126 key = hash_long(ip, hash->size_bits);
1130 hhd = &hash->buckets[key];
1132 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1133 if (entry->ip == ip)
1139 static void __add_hash_entry(struct ftrace_hash *hash,
1140 struct ftrace_func_entry *entry)
1142 struct hlist_head *hhd;
1145 if (hash->size_bits)
1146 key = hash_long(entry->ip, hash->size_bits);
1150 hhd = &hash->buckets[key];
1151 hlist_add_head(&entry->hlist, hhd);
1155 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1157 struct ftrace_func_entry *entry;
1159 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1164 __add_hash_entry(hash, entry);
1170 free_hash_entry(struct ftrace_hash *hash,
1171 struct ftrace_func_entry *entry)
1173 hlist_del(&entry->hlist);
1179 remove_hash_entry(struct ftrace_hash *hash,
1180 struct ftrace_func_entry *entry)
1182 hlist_del(&entry->hlist);
1186 static void ftrace_hash_clear(struct ftrace_hash *hash)
1188 struct hlist_head *hhd;
1189 struct hlist_node *tn;
1190 struct ftrace_func_entry *entry;
1191 int size = 1 << hash->size_bits;
1197 for (i = 0; i < size; i++) {
1198 hhd = &hash->buckets[i];
1199 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1200 free_hash_entry(hash, entry);
1202 FTRACE_WARN_ON(hash->count);
1205 static void free_ftrace_hash(struct ftrace_hash *hash)
1207 if (!hash || hash == EMPTY_HASH)
1209 ftrace_hash_clear(hash);
1210 kfree(hash->buckets);
1214 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1216 struct ftrace_hash *hash;
1218 hash = container_of(rcu, struct ftrace_hash, rcu);
1219 free_ftrace_hash(hash);
1222 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1224 if (!hash || hash == EMPTY_HASH)
1226 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1229 void ftrace_free_filter(struct ftrace_ops *ops)
1231 ftrace_ops_init(ops);
1232 free_ftrace_hash(ops->filter_hash);
1233 free_ftrace_hash(ops->notrace_hash);
1236 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1238 struct ftrace_hash *hash;
1241 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1245 size = 1 << size_bits;
1246 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1248 if (!hash->buckets) {
1253 hash->size_bits = size_bits;
1258 static struct ftrace_hash *
1259 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1261 struct ftrace_func_entry *entry;
1262 struct ftrace_hash *new_hash;
1267 new_hash = alloc_ftrace_hash(size_bits);
1272 if (ftrace_hash_empty(hash))
1275 size = 1 << hash->size_bits;
1276 for (i = 0; i < size; i++) {
1277 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1278 ret = add_hash_entry(new_hash, entry->ip);
1284 FTRACE_WARN_ON(new_hash->count != hash->count);
1289 free_ftrace_hash(new_hash);
1294 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1296 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1299 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1300 struct ftrace_hash **dst, struct ftrace_hash *src)
1302 struct ftrace_func_entry *entry;
1303 struct hlist_node *tn;
1304 struct hlist_head *hhd;
1305 struct ftrace_hash *old_hash;
1306 struct ftrace_hash *new_hash;
1307 int size = src->count;
1313 * Remove the current set, update the hash and add
1316 ftrace_hash_rec_disable(ops, enable);
1319 * If the new source is empty, just free dst and assign it
1323 free_ftrace_hash_rcu(*dst);
1324 rcu_assign_pointer(*dst, EMPTY_HASH);
1325 /* still need to update the function records */
1331 * Make the hash size about 1/2 the # found
1333 for (size /= 2; size; size >>= 1)
1336 /* Don't allocate too much */
1337 if (bits > FTRACE_HASH_MAX_BITS)
1338 bits = FTRACE_HASH_MAX_BITS;
1341 new_hash = alloc_ftrace_hash(bits);
1345 size = 1 << src->size_bits;
1346 for (i = 0; i < size; i++) {
1347 hhd = &src->buckets[i];
1348 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1349 remove_hash_entry(src, entry);
1350 __add_hash_entry(new_hash, entry);
1355 rcu_assign_pointer(*dst, new_hash);
1356 free_ftrace_hash_rcu(old_hash);
1361 * Enable regardless of ret:
1362 * On success, we enable the new hash.
1363 * On failure, we re-enable the original hash.
1365 ftrace_hash_rec_enable(ops, enable);
1371 * Test the hashes for this ops to see if we want to call
1372 * the ops->func or not.
1374 * It's a match if the ip is in the ops->filter_hash or
1375 * the filter_hash does not exist or is empty,
1377 * the ip is not in the ops->notrace_hash.
1379 * This needs to be called with preemption disabled as
1380 * the hashes are freed with call_rcu_sched().
1383 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1385 struct ftrace_hash *filter_hash;
1386 struct ftrace_hash *notrace_hash;
1389 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1391 * There's a small race when adding ops that the ftrace handler
1392 * that wants regs, may be called without them. We can not
1393 * allow that handler to be called if regs is NULL.
1395 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1399 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1400 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1402 if ((ftrace_hash_empty(filter_hash) ||
1403 ftrace_lookup_ip(filter_hash, ip)) &&
1404 (ftrace_hash_empty(notrace_hash) ||
1405 !ftrace_lookup_ip(notrace_hash, ip)))
1414 * This is a double for. Do not use 'break' to break out of the loop,
1415 * you must use a goto.
1417 #define do_for_each_ftrace_rec(pg, rec) \
1418 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1420 for (_____i = 0; _____i < pg->index; _____i++) { \
1421 rec = &pg->records[_____i];
1423 #define while_for_each_ftrace_rec() \
1428 static int ftrace_cmp_recs(const void *a, const void *b)
1430 const struct dyn_ftrace *key = a;
1431 const struct dyn_ftrace *rec = b;
1433 if (key->flags < rec->ip)
1435 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1440 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1442 struct ftrace_page *pg;
1443 struct dyn_ftrace *rec;
1444 struct dyn_ftrace key;
1447 key.flags = end; /* overload flags, as it is unsigned long */
1449 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1450 if (end < pg->records[0].ip ||
1451 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1453 rec = bsearch(&key, pg->records, pg->index,
1454 sizeof(struct dyn_ftrace),
1464 * ftrace_location - return true if the ip giving is a traced location
1465 * @ip: the instruction pointer to check
1467 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1468 * That is, the instruction that is either a NOP or call to
1469 * the function tracer. It checks the ftrace internal tables to
1470 * determine if the address belongs or not.
1472 unsigned long ftrace_location(unsigned long ip)
1474 return ftrace_location_range(ip, ip);
1478 * ftrace_text_reserved - return true if range contains an ftrace location
1479 * @start: start of range to search
1480 * @end: end of range to search (inclusive). @end points to the last byte to check.
1482 * Returns 1 if @start and @end contains a ftrace location.
1483 * That is, the instruction that is either a NOP or call to
1484 * the function tracer. It checks the ftrace internal tables to
1485 * determine if the address belongs or not.
1487 int ftrace_text_reserved(const void *start, const void *end)
1491 ret = ftrace_location_range((unsigned long)start,
1492 (unsigned long)end);
1497 /* Test if ops registered to this rec needs regs */
1498 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1500 struct ftrace_ops *ops;
1501 bool keep_regs = false;
1503 for (ops = ftrace_ops_list;
1504 ops != &ftrace_list_end; ops = ops->next) {
1505 /* pass rec in as regs to have non-NULL val */
1506 if (ftrace_ops_test(ops, rec->ip, rec)) {
1507 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1517 static void ftrace_remove_tramp(struct ftrace_ops *ops,
1518 struct dyn_ftrace *rec)
1520 struct ftrace_func_entry *entry;
1522 entry = ftrace_lookup_ip(ops->tramp_hash, rec->ip);
1527 * The tramp_hash entry will be removed at time
1531 rec->flags &= ~FTRACE_FL_TRAMP;
1534 static void ftrace_clear_tramps(struct dyn_ftrace *rec)
1536 struct ftrace_ops *op;
1538 do_for_each_ftrace_op(op, ftrace_ops_list) {
1539 if (op->trampolines)
1540 ftrace_remove_tramp(op, rec);
1541 } while_for_each_ftrace_op(op);
1544 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1548 struct ftrace_hash *hash;
1549 struct ftrace_hash *other_hash;
1550 struct ftrace_page *pg;
1551 struct dyn_ftrace *rec;
1555 /* Only update if the ops has been registered */
1556 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1560 * In the filter_hash case:
1561 * If the count is zero, we update all records.
1562 * Otherwise we just update the items in the hash.
1564 * In the notrace_hash case:
1565 * We enable the update in the hash.
1566 * As disabling notrace means enabling the tracing,
1567 * and enabling notrace means disabling, the inc variable
1571 hash = ops->filter_hash;
1572 other_hash = ops->notrace_hash;
1573 if (ftrace_hash_empty(hash))
1577 hash = ops->notrace_hash;
1578 other_hash = ops->filter_hash;
1580 * If the notrace hash has no items,
1581 * then there's nothing to do.
1583 if (ftrace_hash_empty(hash))
1587 do_for_each_ftrace_rec(pg, rec) {
1588 int in_other_hash = 0;
1594 * Only the filter_hash affects all records.
1595 * Update if the record is not in the notrace hash.
1597 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1600 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1601 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1604 * If filter_hash is set, we want to match all functions
1605 * that are in the hash but not in the other hash.
1607 * If filter_hash is not set, then we are decrementing.
1608 * That means we match anything that is in the hash
1609 * and also in the other_hash. That is, we need to turn
1610 * off functions in the other hash because they are disabled
1613 if (filter_hash && in_hash && !in_other_hash)
1615 else if (!filter_hash && in_hash &&
1616 (in_other_hash || ftrace_hash_empty(other_hash)))
1624 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1628 * If there's only a single callback registered to a
1629 * function, and the ops has a trampoline registered
1630 * for it, then we can call it directly.
1632 if (ftrace_rec_count(rec) == 1 && ops->trampoline) {
1633 rec->flags |= FTRACE_FL_TRAMP;
1637 * If we are adding another function callback
1638 * to this function, and the previous had a
1639 * trampoline used, then we need to go back to
1640 * the default trampoline.
1642 rec->flags &= ~FTRACE_FL_TRAMP;
1644 /* remove trampolines from any ops for this rec */
1645 ftrace_clear_tramps(rec);
1649 * If any ops wants regs saved for this function
1650 * then all ops will get saved regs.
1652 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1653 rec->flags |= FTRACE_FL_REGS;
1655 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1659 if (ops->trampoline && !ftrace_rec_count(rec))
1660 ftrace_remove_tramp(ops, rec);
1663 * If the rec had REGS enabled and the ops that is
1664 * being removed had REGS set, then see if there is
1665 * still any ops for this record that wants regs.
1666 * If not, we can stop recording them.
1668 if (ftrace_rec_count(rec) > 0 &&
1669 rec->flags & FTRACE_FL_REGS &&
1670 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1671 if (!test_rec_ops_needs_regs(rec))
1672 rec->flags &= ~FTRACE_FL_REGS;
1676 * flags will be cleared in ftrace_check_record()
1677 * if rec count is zero.
1681 /* Shortcut, if we handled all records, we are done. */
1682 if (!all && count == hash->count)
1684 } while_for_each_ftrace_rec();
1687 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1690 __ftrace_hash_rec_update(ops, filter_hash, 0);
1693 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1696 __ftrace_hash_rec_update(ops, filter_hash, 1);
1699 static void print_ip_ins(const char *fmt, unsigned char *p)
1703 printk(KERN_CONT "%s", fmt);
1705 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1706 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1710 * ftrace_bug - report and shutdown function tracer
1711 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1712 * @ip: The address that failed
1714 * The arch code that enables or disables the function tracing
1715 * can call ftrace_bug() when it has detected a problem in
1716 * modifying the code. @failed should be one of either:
1717 * EFAULT - if the problem happens on reading the @ip address
1718 * EINVAL - if what is read at @ip is not what was expected
1719 * EPERM - if the problem happens on writting to the @ip address
1721 void ftrace_bug(int failed, unsigned long ip)
1725 FTRACE_WARN_ON_ONCE(1);
1726 pr_info("ftrace faulted on modifying ");
1730 FTRACE_WARN_ON_ONCE(1);
1731 pr_info("ftrace failed to modify ");
1733 print_ip_ins(" actual: ", (unsigned char *)ip);
1734 printk(KERN_CONT "\n");
1737 FTRACE_WARN_ON_ONCE(1);
1738 pr_info("ftrace faulted on writing ");
1742 FTRACE_WARN_ON_ONCE(1);
1743 pr_info("ftrace faulted on unknown error ");
1748 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1750 unsigned long flag = 0UL;
1753 * If we are updating calls:
1755 * If the record has a ref count, then we need to enable it
1756 * because someone is using it.
1758 * Otherwise we make sure its disabled.
1760 * If we are disabling calls, then disable all records that
1763 if (enable && ftrace_rec_count(rec))
1764 flag = FTRACE_FL_ENABLED;
1767 * If enabling and the REGS flag does not match the REGS_EN, or
1768 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
1769 * this record. Set flags to fail the compare against ENABLED.
1772 if (!(rec->flags & FTRACE_FL_REGS) !=
1773 !(rec->flags & FTRACE_FL_REGS_EN))
1774 flag |= FTRACE_FL_REGS;
1776 if (!(rec->flags & FTRACE_FL_TRAMP) !=
1777 !(rec->flags & FTRACE_FL_TRAMP_EN))
1778 flag |= FTRACE_FL_TRAMP;
1781 /* If the state of this record hasn't changed, then do nothing */
1782 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1783 return FTRACE_UPDATE_IGNORE;
1786 /* Save off if rec is being enabled (for return value) */
1787 flag ^= rec->flags & FTRACE_FL_ENABLED;
1790 rec->flags |= FTRACE_FL_ENABLED;
1791 if (flag & FTRACE_FL_REGS) {
1792 if (rec->flags & FTRACE_FL_REGS)
1793 rec->flags |= FTRACE_FL_REGS_EN;
1795 rec->flags &= ~FTRACE_FL_REGS_EN;
1797 if (flag & FTRACE_FL_TRAMP) {
1798 if (rec->flags & FTRACE_FL_TRAMP)
1799 rec->flags |= FTRACE_FL_TRAMP_EN;
1801 rec->flags &= ~FTRACE_FL_TRAMP_EN;
1806 * If this record is being updated from a nop, then
1807 * return UPDATE_MAKE_CALL.
1809 * return UPDATE_MODIFY_CALL to tell the caller to convert
1810 * from the save regs, to a non-save regs function or
1811 * vice versa, or from a trampoline call.
1813 if (flag & FTRACE_FL_ENABLED)
1814 return FTRACE_UPDATE_MAKE_CALL;
1816 return FTRACE_UPDATE_MODIFY_CALL;
1820 /* If there's no more users, clear all flags */
1821 if (!ftrace_rec_count(rec))
1824 /* Just disable the record (keep REGS state) */
1825 rec->flags &= ~FTRACE_FL_ENABLED;
1828 return FTRACE_UPDATE_MAKE_NOP;
1832 * ftrace_update_record, set a record that now is tracing or not
1833 * @rec: the record to update
1834 * @enable: set to 1 if the record is tracing, zero to force disable
1836 * The records that represent all functions that can be traced need
1837 * to be updated when tracing has been enabled.
1839 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1841 return ftrace_check_record(rec, enable, 1);
1845 * ftrace_test_record, check if the record has been enabled or not
1846 * @rec: the record to test
1847 * @enable: set to 1 to check if enabled, 0 if it is disabled
1849 * The arch code may need to test if a record is already set to
1850 * tracing to determine how to modify the function code that it
1853 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1855 return ftrace_check_record(rec, enable, 0);
1858 static struct ftrace_ops *
1859 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
1861 struct ftrace_ops *op;
1863 /* Removed ops need to be tested first */
1864 if (removed_ops && removed_ops->tramp_hash) {
1865 if (ftrace_lookup_ip(removed_ops->tramp_hash, rec->ip))
1869 do_for_each_ftrace_op(op, ftrace_ops_list) {
1870 if (!op->tramp_hash)
1873 if (ftrace_lookup_ip(op->tramp_hash, rec->ip))
1876 } while_for_each_ftrace_op(op);
1881 static struct ftrace_ops *
1882 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
1884 struct ftrace_ops *op;
1886 do_for_each_ftrace_op(op, ftrace_ops_list) {
1887 /* pass rec in as regs to have non-NULL val */
1888 if (ftrace_ops_test(op, rec->ip, rec))
1890 } while_for_each_ftrace_op(op);
1896 * ftrace_get_addr_new - Get the call address to set to
1897 * @rec: The ftrace record descriptor
1899 * If the record has the FTRACE_FL_REGS set, that means that it
1900 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
1901 * is not not set, then it wants to convert to the normal callback.
1903 * Returns the address of the trampoline to set to
1905 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
1907 struct ftrace_ops *ops;
1909 /* Trampolines take precedence over regs */
1910 if (rec->flags & FTRACE_FL_TRAMP) {
1911 ops = ftrace_find_tramp_ops_new(rec);
1912 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
1913 pr_warning("Bad trampoline accounting at: %p (%pS)\n",
1914 (void *)rec->ip, (void *)rec->ip);
1915 /* Ftrace is shutting down, return anything */
1916 return (unsigned long)FTRACE_ADDR;
1918 return ops->trampoline;
1921 if (rec->flags & FTRACE_FL_REGS)
1922 return (unsigned long)FTRACE_REGS_ADDR;
1924 return (unsigned long)FTRACE_ADDR;
1928 * ftrace_get_addr_curr - Get the call address that is already there
1929 * @rec: The ftrace record descriptor
1931 * The FTRACE_FL_REGS_EN is set when the record already points to
1932 * a function that saves all the regs. Basically the '_EN' version
1933 * represents the current state of the function.
1935 * Returns the address of the trampoline that is currently being called
1937 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
1939 struct ftrace_ops *ops;
1941 /* Trampolines take precedence over regs */
1942 if (rec->flags & FTRACE_FL_TRAMP_EN) {
1943 ops = ftrace_find_tramp_ops_curr(rec);
1944 if (FTRACE_WARN_ON(!ops)) {
1945 pr_warning("Bad trampoline accounting at: %p (%pS)\n",
1946 (void *)rec->ip, (void *)rec->ip);
1947 /* Ftrace is shutting down, return anything */
1948 return (unsigned long)FTRACE_ADDR;
1950 return ops->trampoline;
1953 if (rec->flags & FTRACE_FL_REGS_EN)
1954 return (unsigned long)FTRACE_REGS_ADDR;
1956 return (unsigned long)FTRACE_ADDR;
1960 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1962 unsigned long ftrace_old_addr;
1963 unsigned long ftrace_addr;
1966 ftrace_addr = ftrace_get_addr_new(rec);
1968 /* This needs to be done before we call ftrace_update_record */
1969 ftrace_old_addr = ftrace_get_addr_curr(rec);
1971 ret = ftrace_update_record(rec, enable);
1974 case FTRACE_UPDATE_IGNORE:
1977 case FTRACE_UPDATE_MAKE_CALL:
1978 return ftrace_make_call(rec, ftrace_addr);
1980 case FTRACE_UPDATE_MAKE_NOP:
1981 return ftrace_make_nop(NULL, rec, ftrace_addr);
1983 case FTRACE_UPDATE_MODIFY_CALL:
1984 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1987 return -1; /* unknow ftrace bug */
1990 void __weak ftrace_replace_code(int enable)
1992 struct dyn_ftrace *rec;
1993 struct ftrace_page *pg;
1996 if (unlikely(ftrace_disabled))
1999 do_for_each_ftrace_rec(pg, rec) {
2000 failed = __ftrace_replace_code(rec, enable);
2002 ftrace_bug(failed, rec->ip);
2003 /* Stop processing */
2006 } while_for_each_ftrace_rec();
2009 struct ftrace_rec_iter {
2010 struct ftrace_page *pg;
2015 * ftrace_rec_iter_start, start up iterating over traced functions
2017 * Returns an iterator handle that is used to iterate over all
2018 * the records that represent address locations where functions
2021 * May return NULL if no records are available.
2023 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2026 * We only use a single iterator.
2027 * Protected by the ftrace_lock mutex.
2029 static struct ftrace_rec_iter ftrace_rec_iter;
2030 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2032 iter->pg = ftrace_pages_start;
2035 /* Could have empty pages */
2036 while (iter->pg && !iter->pg->index)
2037 iter->pg = iter->pg->next;
2046 * ftrace_rec_iter_next, get the next record to process.
2047 * @iter: The handle to the iterator.
2049 * Returns the next iterator after the given iterator @iter.
2051 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2055 if (iter->index >= iter->pg->index) {
2056 iter->pg = iter->pg->next;
2059 /* Could have empty pages */
2060 while (iter->pg && !iter->pg->index)
2061 iter->pg = iter->pg->next;
2071 * ftrace_rec_iter_record, get the record at the iterator location
2072 * @iter: The current iterator location
2074 * Returns the record that the current @iter is at.
2076 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2078 return &iter->pg->records[iter->index];
2082 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2089 if (unlikely(ftrace_disabled))
2092 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2094 ftrace_bug(ret, ip);
2101 * archs can override this function if they must do something
2102 * before the modifying code is performed.
2104 int __weak ftrace_arch_code_modify_prepare(void)
2110 * archs can override this function if they must do something
2111 * after the modifying code is performed.
2113 int __weak ftrace_arch_code_modify_post_process(void)
2118 void ftrace_modify_all_code(int command)
2120 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2124 * If the ftrace_caller calls a ftrace_ops func directly,
2125 * we need to make sure that it only traces functions it
2126 * expects to trace. When doing the switch of functions,
2127 * we need to update to the ftrace_ops_list_func first
2128 * before the transition between old and new calls are set,
2129 * as the ftrace_ops_list_func will check the ops hashes
2130 * to make sure the ops are having the right functions
2134 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2135 if (FTRACE_WARN_ON(err))
2139 if (command & FTRACE_UPDATE_CALLS)
2140 ftrace_replace_code(1);
2141 else if (command & FTRACE_DISABLE_CALLS)
2142 ftrace_replace_code(0);
2144 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2145 function_trace_op = set_function_trace_op;
2147 /* If irqs are disabled, we are in stop machine */
2148 if (!irqs_disabled())
2149 smp_call_function(ftrace_sync_ipi, NULL, 1);
2150 err = ftrace_update_ftrace_func(ftrace_trace_function);
2151 if (FTRACE_WARN_ON(err))
2155 if (command & FTRACE_START_FUNC_RET)
2156 err = ftrace_enable_ftrace_graph_caller();
2157 else if (command & FTRACE_STOP_FUNC_RET)
2158 err = ftrace_disable_ftrace_graph_caller();
2159 FTRACE_WARN_ON(err);
2162 static int __ftrace_modify_code(void *data)
2164 int *command = data;
2166 ftrace_modify_all_code(*command);
2172 * ftrace_run_stop_machine, go back to the stop machine method
2173 * @command: The command to tell ftrace what to do
2175 * If an arch needs to fall back to the stop machine method, the
2176 * it can call this function.
2178 void ftrace_run_stop_machine(int command)
2180 stop_machine(__ftrace_modify_code, &command, NULL);
2184 * arch_ftrace_update_code, modify the code to trace or not trace
2185 * @command: The command that needs to be done
2187 * Archs can override this function if it does not need to
2188 * run stop_machine() to modify code.
2190 void __weak arch_ftrace_update_code(int command)
2192 ftrace_run_stop_machine(command);
2195 static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops)
2197 struct ftrace_page *pg;
2198 struct dyn_ftrace *rec;
2202 size = ops->trampolines;
2205 * Make the hash size about 1/2 the # found
2207 for (size /= 2; size; size >>= 1)
2210 ops->tramp_hash = alloc_ftrace_hash(bits);
2212 * TODO: a failed allocation is going to screw up
2213 * the accounting of what needs to be modified
2214 * and not. For now, we kill ftrace if we fail
2215 * to allocate here. But there are ways around this,
2216 * but that will take a little more work.
2218 if (!ops->tramp_hash)
2221 do_for_each_ftrace_rec(pg, rec) {
2222 if (ftrace_rec_count(rec) == 1 &&
2223 ftrace_ops_test(ops, rec->ip, rec)) {
2225 /* This record had better have a trampoline */
2226 if (FTRACE_WARN_ON(!(rec->flags & FTRACE_FL_TRAMP_EN)))
2229 ret = add_hash_entry(ops->tramp_hash, rec->ip);
2233 } while_for_each_ftrace_rec();
2238 static int ftrace_save_tramp_hashes(void)
2240 struct ftrace_ops *op;
2244 * Now that any trampoline is being used, we need to save the
2245 * hashes for the ops that have them. This allows the mapping
2246 * back from the record to the ops that has the trampoline to
2247 * know what code is being replaced. Modifying code must always
2248 * verify what it is changing.
2250 do_for_each_ftrace_op(op, ftrace_ops_list) {
2252 /* The tramp_hash is recreated each time. */
2253 free_ftrace_hash(op->tramp_hash);
2254 op->tramp_hash = NULL;
2256 if (op->trampolines) {
2257 ret = ftrace_save_ops_tramp_hash(op);
2262 } while_for_each_ftrace_op(op);
2267 static void ftrace_run_update_code(int command)
2271 ret = ftrace_arch_code_modify_prepare();
2272 FTRACE_WARN_ON(ret);
2276 * Do not call function tracer while we update the code.
2277 * We are in stop machine.
2279 function_trace_stop++;
2282 * By default we use stop_machine() to modify the code.
2283 * But archs can do what ever they want as long as it
2284 * is safe. The stop_machine() is the safest, but also
2285 * produces the most overhead.
2287 arch_ftrace_update_code(command);
2289 function_trace_stop--;
2291 ret = ftrace_arch_code_modify_post_process();
2292 FTRACE_WARN_ON(ret);
2294 ret = ftrace_save_tramp_hashes();
2295 FTRACE_WARN_ON(ret);
2298 static ftrace_func_t saved_ftrace_func;
2299 static int ftrace_start_up;
2300 static int global_start_up;
2302 static void control_ops_free(struct ftrace_ops *ops)
2304 free_percpu(ops->disabled);
2307 static void ftrace_startup_enable(int command)
2309 if (saved_ftrace_func != ftrace_trace_function) {
2310 saved_ftrace_func = ftrace_trace_function;
2311 command |= FTRACE_UPDATE_TRACE_FUNC;
2314 if (!command || !ftrace_enabled)
2317 ftrace_run_update_code(command);
2320 static int ftrace_startup(struct ftrace_ops *ops, int command)
2324 if (unlikely(ftrace_disabled))
2327 ret = __register_ftrace_function(ops);
2332 command |= FTRACE_UPDATE_CALLS;
2334 ops->flags |= FTRACE_OPS_FL_ENABLED;
2336 ftrace_hash_rec_enable(ops, 1);
2338 ftrace_startup_enable(command);
2343 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2347 if (unlikely(ftrace_disabled))
2350 ret = __unregister_ftrace_function(ops);
2356 * Just warn in case of unbalance, no need to kill ftrace, it's not
2357 * critical but the ftrace_call callers may be never nopped again after
2358 * further ftrace uses.
2360 WARN_ON_ONCE(ftrace_start_up < 0);
2362 ftrace_hash_rec_disable(ops, 1);
2364 if (!global_start_up)
2365 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2367 command |= FTRACE_UPDATE_CALLS;
2369 if (saved_ftrace_func != ftrace_trace_function) {
2370 saved_ftrace_func = ftrace_trace_function;
2371 command |= FTRACE_UPDATE_TRACE_FUNC;
2374 if (!command || !ftrace_enabled) {
2376 * If these are control ops, they still need their
2377 * per_cpu field freed. Since, function tracing is
2378 * not currently active, we can just free them
2379 * without synchronizing all CPUs.
2381 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2382 control_ops_free(ops);
2387 * If the ops uses a trampoline, then it needs to be
2388 * tested first on update.
2392 ftrace_run_update_code(command);
2397 * Dynamic ops may be freed, we must make sure that all
2398 * callers are done before leaving this function.
2399 * The same goes for freeing the per_cpu data of the control
2402 * Again, normal synchronize_sched() is not good enough.
2403 * We need to do a hard force of sched synchronization.
2404 * This is because we use preempt_disable() to do RCU, but
2405 * the function tracers can be called where RCU is not watching
2406 * (like before user_exit()). We can not rely on the RCU
2407 * infrastructure to do the synchronization, thus we must do it
2410 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2411 schedule_on_each_cpu(ftrace_sync);
2413 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2414 control_ops_free(ops);
2420 static void ftrace_startup_sysctl(void)
2422 if (unlikely(ftrace_disabled))
2425 /* Force update next time */
2426 saved_ftrace_func = NULL;
2427 /* ftrace_start_up is true if we want ftrace running */
2428 if (ftrace_start_up)
2429 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2432 static void ftrace_shutdown_sysctl(void)
2434 if (unlikely(ftrace_disabled))
2437 /* ftrace_start_up is true if ftrace is running */
2438 if (ftrace_start_up)
2439 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2442 static cycle_t ftrace_update_time;
2443 unsigned long ftrace_update_tot_cnt;
2445 static inline int ops_traces_mod(struct ftrace_ops *ops)
2448 * Filter_hash being empty will default to trace module.
2449 * But notrace hash requires a test of individual module functions.
2451 return ftrace_hash_empty(ops->filter_hash) &&
2452 ftrace_hash_empty(ops->notrace_hash);
2456 * Check if the current ops references the record.
2458 * If the ops traces all functions, then it was already accounted for.
2459 * If the ops does not trace the current record function, skip it.
2460 * If the ops ignores the function via notrace filter, skip it.
2463 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2465 /* If ops isn't enabled, ignore it */
2466 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2469 /* If ops traces all mods, we already accounted for it */
2470 if (ops_traces_mod(ops))
2473 /* The function must be in the filter */
2474 if (!ftrace_hash_empty(ops->filter_hash) &&
2475 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2478 /* If in notrace hash, we ignore it too */
2479 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2485 static int referenced_filters(struct dyn_ftrace *rec)
2487 struct ftrace_ops *ops;
2490 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2491 if (ops_references_rec(ops, rec))
2498 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2500 struct ftrace_page *pg;
2501 struct dyn_ftrace *p;
2502 cycle_t start, stop;
2503 unsigned long update_cnt = 0;
2504 unsigned long ref = 0;
2509 * When adding a module, we need to check if tracers are
2510 * currently enabled and if they are set to trace all functions.
2511 * If they are, we need to enable the module functions as well
2512 * as update the reference counts for those function records.
2515 struct ftrace_ops *ops;
2517 for (ops = ftrace_ops_list;
2518 ops != &ftrace_list_end; ops = ops->next) {
2519 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2520 if (ops_traces_mod(ops))
2528 start = ftrace_now(raw_smp_processor_id());
2530 for (pg = new_pgs; pg; pg = pg->next) {
2532 for (i = 0; i < pg->index; i++) {
2535 /* If something went wrong, bail without enabling anything */
2536 if (unlikely(ftrace_disabled))
2539 p = &pg->records[i];
2541 cnt += referenced_filters(p);
2545 * Do the initial record conversion from mcount jump
2546 * to the NOP instructions.
2548 if (!ftrace_code_disable(mod, p))
2554 * If the tracing is enabled, go ahead and enable the record.
2556 * The reason not to enable the record immediatelly is the
2557 * inherent check of ftrace_make_nop/ftrace_make_call for
2558 * correct previous instructions. Making first the NOP
2559 * conversion puts the module to the correct state, thus
2560 * passing the ftrace_make_call check.
2562 if (ftrace_start_up && cnt) {
2563 int failed = __ftrace_replace_code(p, 1);
2565 ftrace_bug(failed, p->ip);
2570 stop = ftrace_now(raw_smp_processor_id());
2571 ftrace_update_time = stop - start;
2572 ftrace_update_tot_cnt += update_cnt;
2577 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2582 if (WARN_ON(!count))
2585 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2588 * We want to fill as much as possible. No more than a page
2591 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2595 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2598 /* if we can't allocate this size, try something smaller */
2605 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2614 static struct ftrace_page *
2615 ftrace_allocate_pages(unsigned long num_to_init)
2617 struct ftrace_page *start_pg;
2618 struct ftrace_page *pg;
2625 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2630 * Try to allocate as much as possible in one continues
2631 * location that fills in all of the space. We want to
2632 * waste as little space as possible.
2635 cnt = ftrace_allocate_records(pg, num_to_init);
2643 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2654 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2655 free_pages((unsigned long)pg->records, order);
2656 start_pg = pg->next;
2660 pr_info("ftrace: FAILED to allocate memory for functions\n");
2664 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2666 struct ftrace_iterator {
2669 struct ftrace_page *pg;
2670 struct dyn_ftrace *func;
2671 struct ftrace_func_probe *probe;
2672 struct trace_parser parser;
2673 struct ftrace_hash *hash;
2674 struct ftrace_ops *ops;
2681 t_hash_next(struct seq_file *m, loff_t *pos)
2683 struct ftrace_iterator *iter = m->private;
2684 struct hlist_node *hnd = NULL;
2685 struct hlist_head *hhd;
2691 hnd = &iter->probe->node;
2693 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2696 hhd = &ftrace_func_hash[iter->hidx];
2698 if (hlist_empty(hhd)) {
2714 if (WARN_ON_ONCE(!hnd))
2717 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2722 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2724 struct ftrace_iterator *iter = m->private;
2728 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2731 if (iter->func_pos > *pos)
2735 for (l = 0; l <= (*pos - iter->func_pos); ) {
2736 p = t_hash_next(m, &l);
2743 /* Only set this if we have an item */
2744 iter->flags |= FTRACE_ITER_HASH;
2750 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2752 struct ftrace_func_probe *rec;
2755 if (WARN_ON_ONCE(!rec))
2758 if (rec->ops->print)
2759 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2761 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2764 seq_printf(m, ":%p", rec->data);
2771 t_next(struct seq_file *m, void *v, loff_t *pos)
2773 struct ftrace_iterator *iter = m->private;
2774 struct ftrace_ops *ops = iter->ops;
2775 struct dyn_ftrace *rec = NULL;
2777 if (unlikely(ftrace_disabled))
2780 if (iter->flags & FTRACE_ITER_HASH)
2781 return t_hash_next(m, pos);
2784 iter->pos = iter->func_pos = *pos;
2786 if (iter->flags & FTRACE_ITER_PRINTALL)
2787 return t_hash_start(m, pos);
2790 if (iter->idx >= iter->pg->index) {
2791 if (iter->pg->next) {
2792 iter->pg = iter->pg->next;
2797 rec = &iter->pg->records[iter->idx++];
2798 if (((iter->flags & FTRACE_ITER_FILTER) &&
2799 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2801 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2802 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2804 ((iter->flags & FTRACE_ITER_ENABLED) &&
2805 !(rec->flags & FTRACE_FL_ENABLED))) {
2813 return t_hash_start(m, pos);
2820 static void reset_iter_read(struct ftrace_iterator *iter)
2824 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2827 static void *t_start(struct seq_file *m, loff_t *pos)
2829 struct ftrace_iterator *iter = m->private;
2830 struct ftrace_ops *ops = iter->ops;
2834 mutex_lock(&ftrace_lock);
2836 if (unlikely(ftrace_disabled))
2840 * If an lseek was done, then reset and start from beginning.
2842 if (*pos < iter->pos)
2843 reset_iter_read(iter);
2846 * For set_ftrace_filter reading, if we have the filter
2847 * off, we can short cut and just print out that all
2848 * functions are enabled.
2850 if (iter->flags & FTRACE_ITER_FILTER &&
2851 ftrace_hash_empty(ops->filter_hash)) {
2853 return t_hash_start(m, pos);
2854 iter->flags |= FTRACE_ITER_PRINTALL;
2855 /* reset in case of seek/pread */
2856 iter->flags &= ~FTRACE_ITER_HASH;
2860 if (iter->flags & FTRACE_ITER_HASH)
2861 return t_hash_start(m, pos);
2864 * Unfortunately, we need to restart at ftrace_pages_start
2865 * every time we let go of the ftrace_mutex. This is because
2866 * those pointers can change without the lock.
2868 iter->pg = ftrace_pages_start;
2870 for (l = 0; l <= *pos; ) {
2871 p = t_next(m, p, &l);
2877 return t_hash_start(m, pos);
2882 static void t_stop(struct seq_file *m, void *p)
2884 mutex_unlock(&ftrace_lock);
2887 static int t_show(struct seq_file *m, void *v)
2889 struct ftrace_iterator *iter = m->private;
2890 struct dyn_ftrace *rec;
2892 if (iter->flags & FTRACE_ITER_HASH)
2893 return t_hash_show(m, iter);
2895 if (iter->flags & FTRACE_ITER_PRINTALL) {
2896 seq_printf(m, "#### all functions enabled ####\n");
2905 seq_printf(m, "%ps", (void *)rec->ip);
2906 if (iter->flags & FTRACE_ITER_ENABLED) {
2907 seq_printf(m, " (%ld)%s",
2908 ftrace_rec_count(rec),
2909 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2910 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2911 struct ftrace_ops *ops;
2913 ops = ftrace_find_tramp_ops_curr(rec);
2914 if (ops && ops->trampoline)
2915 seq_printf(m, "\ttramp: %pS",
2916 (void *)ops->trampoline);
2918 seq_printf(m, "\ttramp: ERROR!");
2922 seq_printf(m, "\n");
2927 static const struct seq_operations show_ftrace_seq_ops = {
2935 ftrace_avail_open(struct inode *inode, struct file *file)
2937 struct ftrace_iterator *iter;
2939 if (unlikely(ftrace_disabled))
2942 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2944 iter->pg = ftrace_pages_start;
2945 iter->ops = &global_ops;
2948 return iter ? 0 : -ENOMEM;
2952 ftrace_enabled_open(struct inode *inode, struct file *file)
2954 struct ftrace_iterator *iter;
2956 if (unlikely(ftrace_disabled))
2959 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2961 iter->pg = ftrace_pages_start;
2962 iter->flags = FTRACE_ITER_ENABLED;
2963 iter->ops = &global_ops;
2966 return iter ? 0 : -ENOMEM;
2969 static void ftrace_filter_reset(struct ftrace_hash *hash)
2971 mutex_lock(&ftrace_lock);
2972 ftrace_hash_clear(hash);
2973 mutex_unlock(&ftrace_lock);
2977 * ftrace_regex_open - initialize function tracer filter files
2978 * @ops: The ftrace_ops that hold the hash filters
2979 * @flag: The type of filter to process
2980 * @inode: The inode, usually passed in to your open routine
2981 * @file: The file, usually passed in to your open routine
2983 * ftrace_regex_open() initializes the filter files for the
2984 * @ops. Depending on @flag it may process the filter hash or
2985 * the notrace hash of @ops. With this called from the open
2986 * routine, you can use ftrace_filter_write() for the write
2987 * routine if @flag has FTRACE_ITER_FILTER set, or
2988 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2989 * tracing_lseek() should be used as the lseek routine, and
2990 * release must call ftrace_regex_release().
2993 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2994 struct inode *inode, struct file *file)
2996 struct ftrace_iterator *iter;
2997 struct ftrace_hash *hash;
3000 ftrace_ops_init(ops);
3002 if (unlikely(ftrace_disabled))
3005 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3009 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3017 mutex_lock(&ops->regex_lock);
3019 if (flag & FTRACE_ITER_NOTRACE)
3020 hash = ops->notrace_hash;
3022 hash = ops->filter_hash;
3024 if (file->f_mode & FMODE_WRITE) {
3025 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
3027 trace_parser_put(&iter->parser);
3034 if ((file->f_mode & FMODE_WRITE) &&
3035 (file->f_flags & O_TRUNC))
3036 ftrace_filter_reset(iter->hash);
3038 if (file->f_mode & FMODE_READ) {
3039 iter->pg = ftrace_pages_start;
3041 ret = seq_open(file, &show_ftrace_seq_ops);
3043 struct seq_file *m = file->private_data;
3047 free_ftrace_hash(iter->hash);
3048 trace_parser_put(&iter->parser);
3052 file->private_data = iter;
3055 mutex_unlock(&ops->regex_lock);
3061 ftrace_filter_open(struct inode *inode, struct file *file)
3063 struct ftrace_ops *ops = inode->i_private;
3065 return ftrace_regex_open(ops,
3066 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3071 ftrace_notrace_open(struct inode *inode, struct file *file)
3073 struct ftrace_ops *ops = inode->i_private;
3075 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3079 static int ftrace_match(char *str, char *regex, int len, int type)
3086 if (strcmp(str, regex) == 0)
3089 case MATCH_FRONT_ONLY:
3090 if (strncmp(str, regex, len) == 0)
3093 case MATCH_MIDDLE_ONLY:
3094 if (strstr(str, regex))
3097 case MATCH_END_ONLY:
3099 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
3108 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
3110 struct ftrace_func_entry *entry;
3113 entry = ftrace_lookup_ip(hash, rec->ip);
3115 /* Do nothing if it doesn't exist */
3119 free_hash_entry(hash, entry);
3121 /* Do nothing if it exists */
3125 ret = add_hash_entry(hash, rec->ip);
3131 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
3132 char *regex, int len, int type)
3134 char str[KSYM_SYMBOL_LEN];
3137 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3140 /* module lookup requires matching the module */
3141 if (!modname || strcmp(modname, mod))
3144 /* blank search means to match all funcs in the mod */
3149 return ftrace_match(str, regex, len, type);
3153 match_records(struct ftrace_hash *hash, char *buff,
3154 int len, char *mod, int not)
3156 unsigned search_len = 0;
3157 struct ftrace_page *pg;
3158 struct dyn_ftrace *rec;
3159 int type = MATCH_FULL;
3160 char *search = buff;
3165 type = filter_parse_regex(buff, len, &search, ¬);
3166 search_len = strlen(search);
3169 mutex_lock(&ftrace_lock);
3171 if (unlikely(ftrace_disabled))
3174 do_for_each_ftrace_rec(pg, rec) {
3175 if (ftrace_match_record(rec, mod, search, search_len, type)) {
3176 ret = enter_record(hash, rec, not);
3183 } while_for_each_ftrace_rec();
3185 mutex_unlock(&ftrace_lock);
3191 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3193 return match_records(hash, buff, len, NULL, 0);
3197 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
3201 /* blank or '*' mean the same */
3202 if (strcmp(buff, "*") == 0)
3205 /* handle the case of 'dont filter this module' */
3206 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
3211 return match_records(hash, buff, strlen(buff), mod, not);
3215 * We register the module command as a template to show others how
3216 * to register the a command as well.
3220 ftrace_mod_callback(struct ftrace_hash *hash,
3221 char *func, char *cmd, char *param, int enable)
3227 * cmd == 'mod' because we only registered this func
3228 * for the 'mod' ftrace_func_command.
3229 * But if you register one func with multiple commands,
3230 * you can tell which command was used by the cmd
3234 /* we must have a module name */
3238 mod = strsep(¶m, ":");
3242 ret = ftrace_match_module_records(hash, func, mod);
3251 static struct ftrace_func_command ftrace_mod_cmd = {
3253 .func = ftrace_mod_callback,
3256 static int __init ftrace_mod_cmd_init(void)
3258 return register_ftrace_command(&ftrace_mod_cmd);
3260 core_initcall(ftrace_mod_cmd_init);
3262 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3263 struct ftrace_ops *op, struct pt_regs *pt_regs)
3265 struct ftrace_func_probe *entry;
3266 struct hlist_head *hhd;
3269 key = hash_long(ip, FTRACE_HASH_BITS);
3271 hhd = &ftrace_func_hash[key];
3273 if (hlist_empty(hhd))
3277 * Disable preemption for these calls to prevent a RCU grace
3278 * period. This syncs the hash iteration and freeing of items
3279 * on the hash. rcu_read_lock is too dangerous here.
3281 preempt_disable_notrace();
3282 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3283 if (entry->ip == ip)
3284 entry->ops->func(ip, parent_ip, &entry->data);
3286 preempt_enable_notrace();
3289 static struct ftrace_ops trace_probe_ops __read_mostly =
3291 .func = function_trace_probe_call,
3292 .flags = FTRACE_OPS_FL_INITIALIZED,
3293 INIT_REGEX_LOCK(trace_probe_ops)
3296 static int ftrace_probe_registered;
3298 static void __enable_ftrace_function_probe(void)
3303 if (ftrace_probe_registered) {
3304 /* still need to update the function call sites */
3306 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3310 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3311 struct hlist_head *hhd = &ftrace_func_hash[i];
3315 /* Nothing registered? */
3316 if (i == FTRACE_FUNC_HASHSIZE)
3319 ret = ftrace_startup(&trace_probe_ops, 0);
3321 ftrace_probe_registered = 1;
3324 static void __disable_ftrace_function_probe(void)
3328 if (!ftrace_probe_registered)
3331 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3332 struct hlist_head *hhd = &ftrace_func_hash[i];
3337 /* no more funcs left */
3338 ftrace_shutdown(&trace_probe_ops, 0);
3340 ftrace_probe_registered = 0;
3344 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3346 if (entry->ops->free)
3347 entry->ops->free(entry->ops, entry->ip, &entry->data);
3352 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3355 struct ftrace_func_probe *entry;
3356 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3357 struct ftrace_hash *hash;
3358 struct ftrace_page *pg;
3359 struct dyn_ftrace *rec;
3366 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3367 len = strlen(search);
3369 /* we do not support '!' for function probes */
3373 mutex_lock(&trace_probe_ops.regex_lock);
3375 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3381 if (unlikely(ftrace_disabled)) {
3386 mutex_lock(&ftrace_lock);
3388 do_for_each_ftrace_rec(pg, rec) {
3390 if (!ftrace_match_record(rec, NULL, search, len, type))
3393 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3395 /* If we did not process any, then return error */
3406 * The caller might want to do something special
3407 * for each function we find. We call the callback
3408 * to give the caller an opportunity to do so.
3411 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3412 /* caller does not like this func */
3418 ret = enter_record(hash, rec, 0);
3426 entry->ip = rec->ip;
3428 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3429 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3431 } while_for_each_ftrace_rec();
3433 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3437 __enable_ftrace_function_probe();
3440 mutex_unlock(&ftrace_lock);
3442 mutex_unlock(&trace_probe_ops.regex_lock);
3443 free_ftrace_hash(hash);
3449 PROBE_TEST_FUNC = 1,
3454 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3455 void *data, int flags)
3457 struct ftrace_func_entry *rec_entry;
3458 struct ftrace_func_probe *entry;
3459 struct ftrace_func_probe *p;
3460 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3461 struct list_head free_list;
3462 struct ftrace_hash *hash;
3463 struct hlist_node *tmp;
3464 char str[KSYM_SYMBOL_LEN];
3465 int type = MATCH_FULL;
3469 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3474 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3475 len = strlen(search);
3477 /* we do not support '!' for function probes */
3482 mutex_lock(&trace_probe_ops.regex_lock);
3484 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3486 /* Hmm, should report this somehow */
3489 INIT_LIST_HEAD(&free_list);
3491 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3492 struct hlist_head *hhd = &ftrace_func_hash[i];
3494 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3496 /* break up if statements for readability */
3497 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3500 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3503 /* do this last, since it is the most expensive */
3505 kallsyms_lookup(entry->ip, NULL, NULL,
3507 if (!ftrace_match(str, glob, len, type))
3511 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3512 /* It is possible more than one entry had this ip */
3514 free_hash_entry(hash, rec_entry);
3516 hlist_del_rcu(&entry->node);
3517 list_add(&entry->free_list, &free_list);
3520 mutex_lock(&ftrace_lock);
3521 __disable_ftrace_function_probe();
3523 * Remove after the disable is called. Otherwise, if the last
3524 * probe is removed, a null hash means *all enabled*.
3526 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3527 synchronize_sched();
3528 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3529 list_del(&entry->free_list);
3530 ftrace_free_entry(entry);
3532 mutex_unlock(&ftrace_lock);
3535 mutex_unlock(&trace_probe_ops.regex_lock);
3536 free_ftrace_hash(hash);
3540 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3543 __unregister_ftrace_function_probe(glob, ops, data,
3544 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3548 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3550 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3553 void unregister_ftrace_function_probe_all(char *glob)
3555 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3558 static LIST_HEAD(ftrace_commands);
3559 static DEFINE_MUTEX(ftrace_cmd_mutex);
3562 * Currently we only register ftrace commands from __init, so mark this
3565 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3567 struct ftrace_func_command *p;
3570 mutex_lock(&ftrace_cmd_mutex);
3571 list_for_each_entry(p, &ftrace_commands, list) {
3572 if (strcmp(cmd->name, p->name) == 0) {
3577 list_add(&cmd->list, &ftrace_commands);
3579 mutex_unlock(&ftrace_cmd_mutex);
3585 * Currently we only unregister ftrace commands from __init, so mark
3588 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3590 struct ftrace_func_command *p, *n;
3593 mutex_lock(&ftrace_cmd_mutex);
3594 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3595 if (strcmp(cmd->name, p->name) == 0) {
3597 list_del_init(&p->list);
3602 mutex_unlock(&ftrace_cmd_mutex);
3607 static int ftrace_process_regex(struct ftrace_hash *hash,
3608 char *buff, int len, int enable)
3610 char *func, *command, *next = buff;
3611 struct ftrace_func_command *p;
3614 func = strsep(&next, ":");
3617 ret = ftrace_match_records(hash, func, len);
3627 command = strsep(&next, ":");
3629 mutex_lock(&ftrace_cmd_mutex);
3630 list_for_each_entry(p, &ftrace_commands, list) {
3631 if (strcmp(p->name, command) == 0) {
3632 ret = p->func(hash, func, command, next, enable);
3637 mutex_unlock(&ftrace_cmd_mutex);
3643 ftrace_regex_write(struct file *file, const char __user *ubuf,
3644 size_t cnt, loff_t *ppos, int enable)
3646 struct ftrace_iterator *iter;
3647 struct trace_parser *parser;
3653 if (file->f_mode & FMODE_READ) {
3654 struct seq_file *m = file->private_data;
3657 iter = file->private_data;
3659 if (unlikely(ftrace_disabled))
3662 /* iter->hash is a local copy, so we don't need regex_lock */
3664 parser = &iter->parser;
3665 read = trace_get_user(parser, ubuf, cnt, ppos);
3667 if (read >= 0 && trace_parser_loaded(parser) &&
3668 !trace_parser_cont(parser)) {
3669 ret = ftrace_process_regex(iter->hash, parser->buffer,
3670 parser->idx, enable);
3671 trace_parser_clear(parser);
3682 ftrace_filter_write(struct file *file, const char __user *ubuf,
3683 size_t cnt, loff_t *ppos)
3685 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3689 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3690 size_t cnt, loff_t *ppos)
3692 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3696 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3698 struct ftrace_func_entry *entry;
3700 if (!ftrace_location(ip))
3704 entry = ftrace_lookup_ip(hash, ip);
3707 free_hash_entry(hash, entry);
3711 return add_hash_entry(hash, ip);
3714 static void ftrace_ops_update_code(struct ftrace_ops *ops)
3716 if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
3717 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3721 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3722 unsigned long ip, int remove, int reset, int enable)
3724 struct ftrace_hash **orig_hash;
3725 struct ftrace_hash *hash;
3728 if (unlikely(ftrace_disabled))
3731 mutex_lock(&ops->regex_lock);
3734 orig_hash = &ops->filter_hash;
3736 orig_hash = &ops->notrace_hash;
3738 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3741 goto out_regex_unlock;
3745 ftrace_filter_reset(hash);
3746 if (buf && !ftrace_match_records(hash, buf, len)) {
3748 goto out_regex_unlock;
3751 ret = ftrace_match_addr(hash, ip, remove);
3753 goto out_regex_unlock;
3756 mutex_lock(&ftrace_lock);
3757 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3759 ftrace_ops_update_code(ops);
3761 mutex_unlock(&ftrace_lock);
3764 mutex_unlock(&ops->regex_lock);
3766 free_ftrace_hash(hash);
3771 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3772 int reset, int enable)
3774 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3778 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3779 * @ops - the ops to set the filter with
3780 * @ip - the address to add to or remove from the filter.
3781 * @remove - non zero to remove the ip from the filter
3782 * @reset - non zero to reset all filters before applying this filter.
3784 * Filters denote which functions should be enabled when tracing is enabled
3785 * If @ip is NULL, it failes to update filter.
3787 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3788 int remove, int reset)
3790 ftrace_ops_init(ops);
3791 return ftrace_set_addr(ops, ip, remove, reset, 1);
3793 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3796 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3797 int reset, int enable)
3799 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3803 * ftrace_set_filter - set a function to filter on in ftrace
3804 * @ops - the ops to set the filter with
3805 * @buf - the string that holds the function filter text.
3806 * @len - the length of the string.
3807 * @reset - non zero to reset all filters before applying this filter.
3809 * Filters denote which functions should be enabled when tracing is enabled.
3810 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3812 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3815 ftrace_ops_init(ops);
3816 return ftrace_set_regex(ops, buf, len, reset, 1);
3818 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3821 * ftrace_set_notrace - set a function to not trace in ftrace
3822 * @ops - the ops to set the notrace filter with
3823 * @buf - the string that holds the function notrace text.
3824 * @len - the length of the string.
3825 * @reset - non zero to reset all filters before applying this filter.
3827 * Notrace Filters denote which functions should not be enabled when tracing
3828 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3831 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3834 ftrace_ops_init(ops);
3835 return ftrace_set_regex(ops, buf, len, reset, 0);
3837 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3839 * ftrace_set_global_filter - set a function to filter on with global tracers
3840 * @buf - the string that holds the function filter text.
3841 * @len - the length of the string.
3842 * @reset - non zero to reset all filters before applying this filter.
3844 * Filters denote which functions should be enabled when tracing is enabled.
3845 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3847 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3849 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3851 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3854 * ftrace_set_global_notrace - set a function to not trace with global tracers
3855 * @buf - the string that holds the function notrace text.
3856 * @len - the length of the string.
3857 * @reset - non zero to reset all filters before applying this filter.
3859 * Notrace Filters denote which functions should not be enabled when tracing
3860 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3863 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3865 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3867 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3870 * command line interface to allow users to set filters on boot up.
3872 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3873 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3874 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3876 /* Used by function selftest to not test if filter is set */
3877 bool ftrace_filter_param __initdata;
3879 static int __init set_ftrace_notrace(char *str)
3881 ftrace_filter_param = true;
3882 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3885 __setup("ftrace_notrace=", set_ftrace_notrace);
3887 static int __init set_ftrace_filter(char *str)
3889 ftrace_filter_param = true;
3890 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3893 __setup("ftrace_filter=", set_ftrace_filter);
3895 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3896 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3897 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
3899 static int __init set_graph_function(char *str)
3901 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3904 __setup("ftrace_graph_filter=", set_graph_function);
3906 static void __init set_ftrace_early_graph(char *buf)
3912 func = strsep(&buf, ",");
3913 /* we allow only one expression at a time */
3914 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3915 FTRACE_GRAPH_MAX_FUNCS, func);
3917 printk(KERN_DEBUG "ftrace: function %s not "
3918 "traceable\n", func);
3921 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3924 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3928 ftrace_ops_init(ops);
3931 func = strsep(&buf, ",");
3932 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3936 static void __init set_ftrace_early_filters(void)
3938 if (ftrace_filter_buf[0])
3939 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3940 if (ftrace_notrace_buf[0])
3941 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3942 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3943 if (ftrace_graph_buf[0])
3944 set_ftrace_early_graph(ftrace_graph_buf);
3945 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3948 int ftrace_regex_release(struct inode *inode, struct file *file)
3950 struct seq_file *m = (struct seq_file *)file->private_data;
3951 struct ftrace_iterator *iter;
3952 struct ftrace_hash **orig_hash;
3953 struct trace_parser *parser;
3957 if (file->f_mode & FMODE_READ) {
3959 seq_release(inode, file);
3961 iter = file->private_data;
3963 parser = &iter->parser;
3964 if (trace_parser_loaded(parser)) {
3965 parser->buffer[parser->idx] = 0;
3966 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3969 trace_parser_put(parser);
3971 mutex_lock(&iter->ops->regex_lock);
3973 if (file->f_mode & FMODE_WRITE) {
3974 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3977 orig_hash = &iter->ops->filter_hash;
3979 orig_hash = &iter->ops->notrace_hash;
3981 mutex_lock(&ftrace_lock);
3982 ret = ftrace_hash_move(iter->ops, filter_hash,
3983 orig_hash, iter->hash);
3985 ftrace_ops_update_code(iter->ops);
3987 mutex_unlock(&ftrace_lock);
3990 mutex_unlock(&iter->ops->regex_lock);
3991 free_ftrace_hash(iter->hash);
3997 static const struct file_operations ftrace_avail_fops = {
3998 .open = ftrace_avail_open,
4000 .llseek = seq_lseek,
4001 .release = seq_release_private,
4004 static const struct file_operations ftrace_enabled_fops = {
4005 .open = ftrace_enabled_open,
4007 .llseek = seq_lseek,
4008 .release = seq_release_private,
4011 static const struct file_operations ftrace_filter_fops = {
4012 .open = ftrace_filter_open,
4014 .write = ftrace_filter_write,
4015 .llseek = tracing_lseek,
4016 .release = ftrace_regex_release,
4019 static const struct file_operations ftrace_notrace_fops = {
4020 .open = ftrace_notrace_open,
4022 .write = ftrace_notrace_write,
4023 .llseek = tracing_lseek,
4024 .release = ftrace_regex_release,
4027 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4029 static DEFINE_MUTEX(graph_lock);
4031 int ftrace_graph_count;
4032 int ftrace_graph_notrace_count;
4033 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4034 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4036 struct ftrace_graph_data {
4037 unsigned long *table;
4040 const struct seq_operations *seq_ops;
4044 __g_next(struct seq_file *m, loff_t *pos)
4046 struct ftrace_graph_data *fgd = m->private;
4048 if (*pos >= *fgd->count)
4050 return &fgd->table[*pos];
4054 g_next(struct seq_file *m, void *v, loff_t *pos)
4057 return __g_next(m, pos);
4060 static void *g_start(struct seq_file *m, loff_t *pos)
4062 struct ftrace_graph_data *fgd = m->private;
4064 mutex_lock(&graph_lock);
4066 /* Nothing, tell g_show to print all functions are enabled */
4067 if (!*fgd->count && !*pos)
4070 return __g_next(m, pos);
4073 static void g_stop(struct seq_file *m, void *p)
4075 mutex_unlock(&graph_lock);
4078 static int g_show(struct seq_file *m, void *v)
4080 unsigned long *ptr = v;
4085 if (ptr == (unsigned long *)1) {
4086 seq_printf(m, "#### all functions enabled ####\n");
4090 seq_printf(m, "%ps\n", (void *)*ptr);
4095 static const struct seq_operations ftrace_graph_seq_ops = {
4103 __ftrace_graph_open(struct inode *inode, struct file *file,
4104 struct ftrace_graph_data *fgd)
4108 mutex_lock(&graph_lock);
4109 if ((file->f_mode & FMODE_WRITE) &&
4110 (file->f_flags & O_TRUNC)) {
4112 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4114 mutex_unlock(&graph_lock);
4116 if (file->f_mode & FMODE_READ) {
4117 ret = seq_open(file, fgd->seq_ops);
4119 struct seq_file *m = file->private_data;
4123 file->private_data = fgd;
4129 ftrace_graph_open(struct inode *inode, struct file *file)
4131 struct ftrace_graph_data *fgd;
4133 if (unlikely(ftrace_disabled))
4136 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4140 fgd->table = ftrace_graph_funcs;
4141 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4142 fgd->count = &ftrace_graph_count;
4143 fgd->seq_ops = &ftrace_graph_seq_ops;
4145 return __ftrace_graph_open(inode, file, fgd);
4149 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4151 struct ftrace_graph_data *fgd;
4153 if (unlikely(ftrace_disabled))
4156 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4160 fgd->table = ftrace_graph_notrace_funcs;
4161 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4162 fgd->count = &ftrace_graph_notrace_count;
4163 fgd->seq_ops = &ftrace_graph_seq_ops;
4165 return __ftrace_graph_open(inode, file, fgd);
4169 ftrace_graph_release(struct inode *inode, struct file *file)
4171 if (file->f_mode & FMODE_READ) {
4172 struct seq_file *m = file->private_data;
4175 seq_release(inode, file);
4177 kfree(file->private_data);
4184 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4186 struct dyn_ftrace *rec;
4187 struct ftrace_page *pg;
4196 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
4197 if (!not && *idx >= size)
4200 search_len = strlen(search);
4202 mutex_lock(&ftrace_lock);
4204 if (unlikely(ftrace_disabled)) {
4205 mutex_unlock(&ftrace_lock);
4209 do_for_each_ftrace_rec(pg, rec) {
4211 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
4212 /* if it is in the array */
4214 for (i = 0; i < *idx; i++) {
4215 if (array[i] == rec->ip) {
4224 array[(*idx)++] = rec->ip;
4230 array[i] = array[--(*idx)];
4236 } while_for_each_ftrace_rec();
4238 mutex_unlock(&ftrace_lock);
4247 ftrace_graph_write(struct file *file, const char __user *ubuf,
4248 size_t cnt, loff_t *ppos)
4250 struct trace_parser parser;
4251 ssize_t read, ret = 0;
4252 struct ftrace_graph_data *fgd = file->private_data;
4257 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4260 read = trace_get_user(&parser, ubuf, cnt, ppos);
4262 if (read >= 0 && trace_parser_loaded((&parser))) {
4263 parser.buffer[parser.idx] = 0;
4265 mutex_lock(&graph_lock);
4267 /* we allow only one expression at a time */
4268 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4271 mutex_unlock(&graph_lock);
4277 trace_parser_put(&parser);
4282 static const struct file_operations ftrace_graph_fops = {
4283 .open = ftrace_graph_open,
4285 .write = ftrace_graph_write,
4286 .llseek = tracing_lseek,
4287 .release = ftrace_graph_release,
4290 static const struct file_operations ftrace_graph_notrace_fops = {
4291 .open = ftrace_graph_notrace_open,
4293 .write = ftrace_graph_write,
4294 .llseek = tracing_lseek,
4295 .release = ftrace_graph_release,
4297 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4299 void ftrace_create_filter_files(struct ftrace_ops *ops,
4300 struct dentry *parent)
4303 trace_create_file("set_ftrace_filter", 0644, parent,
4304 ops, &ftrace_filter_fops);
4306 trace_create_file("set_ftrace_notrace", 0644, parent,
4307 ops, &ftrace_notrace_fops);
4311 * The name "destroy_filter_files" is really a misnomer. Although
4312 * in the future, it may actualy delete the files, but this is
4313 * really intended to make sure the ops passed in are disabled
4314 * and that when this function returns, the caller is free to
4317 * The "destroy" name is only to match the "create" name that this
4318 * should be paired with.
4320 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4322 mutex_lock(&ftrace_lock);
4323 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4324 ftrace_shutdown(ops, 0);
4325 ops->flags |= FTRACE_OPS_FL_DELETED;
4326 mutex_unlock(&ftrace_lock);
4329 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
4332 trace_create_file("available_filter_functions", 0444,
4333 d_tracer, NULL, &ftrace_avail_fops);
4335 trace_create_file("enabled_functions", 0444,
4336 d_tracer, NULL, &ftrace_enabled_fops);
4338 ftrace_create_filter_files(&global_ops, d_tracer);
4340 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4341 trace_create_file("set_graph_function", 0444, d_tracer,
4343 &ftrace_graph_fops);
4344 trace_create_file("set_graph_notrace", 0444, d_tracer,
4346 &ftrace_graph_notrace_fops);
4347 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4352 static int ftrace_cmp_ips(const void *a, const void *b)
4354 const unsigned long *ipa = a;
4355 const unsigned long *ipb = b;
4364 static void ftrace_swap_ips(void *a, void *b, int size)
4366 unsigned long *ipa = a;
4367 unsigned long *ipb = b;
4375 static int ftrace_process_locs(struct module *mod,
4376 unsigned long *start,
4379 struct ftrace_page *start_pg;
4380 struct ftrace_page *pg;
4381 struct dyn_ftrace *rec;
4382 unsigned long count;
4385 unsigned long flags = 0; /* Shut up gcc */
4388 count = end - start;
4393 sort(start, count, sizeof(*start),
4394 ftrace_cmp_ips, ftrace_swap_ips);
4396 start_pg = ftrace_allocate_pages(count);
4400 mutex_lock(&ftrace_lock);
4403 * Core and each module needs their own pages, as
4404 * modules will free them when they are removed.
4405 * Force a new page to be allocated for modules.
4408 WARN_ON(ftrace_pages || ftrace_pages_start);
4409 /* First initialization */
4410 ftrace_pages = ftrace_pages_start = start_pg;
4415 if (WARN_ON(ftrace_pages->next)) {
4416 /* Hmm, we have free pages? */
4417 while (ftrace_pages->next)
4418 ftrace_pages = ftrace_pages->next;
4421 ftrace_pages->next = start_pg;
4427 addr = ftrace_call_adjust(*p++);
4429 * Some architecture linkers will pad between
4430 * the different mcount_loc sections of different
4431 * object files to satisfy alignments.
4432 * Skip any NULL pointers.
4437 if (pg->index == pg->size) {
4438 /* We should have allocated enough */
4439 if (WARN_ON(!pg->next))
4444 rec = &pg->records[pg->index++];
4448 /* We should have used all pages */
4451 /* Assign the last page to ftrace_pages */
4455 * We only need to disable interrupts on start up
4456 * because we are modifying code that an interrupt
4457 * may execute, and the modification is not atomic.
4458 * But for modules, nothing runs the code we modify
4459 * until we are finished with it, and there's no
4460 * reason to cause large interrupt latencies while we do it.
4463 local_irq_save(flags);
4464 ftrace_update_code(mod, start_pg);
4466 local_irq_restore(flags);
4469 mutex_unlock(&ftrace_lock);
4474 #ifdef CONFIG_MODULES
4476 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4478 void ftrace_release_mod(struct module *mod)
4480 struct dyn_ftrace *rec;
4481 struct ftrace_page **last_pg;
4482 struct ftrace_page *pg;
4485 mutex_lock(&ftrace_lock);
4487 if (ftrace_disabled)
4491 * Each module has its own ftrace_pages, remove
4492 * them from the list.
4494 last_pg = &ftrace_pages_start;
4495 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4496 rec = &pg->records[0];
4497 if (within_module_core(rec->ip, mod)) {
4499 * As core pages are first, the first
4500 * page should never be a module page.
4502 if (WARN_ON(pg == ftrace_pages_start))
4505 /* Check if we are deleting the last page */
4506 if (pg == ftrace_pages)
4507 ftrace_pages = next_to_ftrace_page(last_pg);
4509 *last_pg = pg->next;
4510 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4511 free_pages((unsigned long)pg->records, order);
4514 last_pg = &pg->next;
4517 mutex_unlock(&ftrace_lock);
4520 static void ftrace_init_module(struct module *mod,
4521 unsigned long *start, unsigned long *end)
4523 if (ftrace_disabled || start == end)
4525 ftrace_process_locs(mod, start, end);
4528 void ftrace_module_init(struct module *mod)
4530 ftrace_init_module(mod, mod->ftrace_callsites,
4531 mod->ftrace_callsites +
4532 mod->num_ftrace_callsites);
4535 static int ftrace_module_notify_exit(struct notifier_block *self,
4536 unsigned long val, void *data)
4538 struct module *mod = data;
4540 if (val == MODULE_STATE_GOING)
4541 ftrace_release_mod(mod);
4546 static int ftrace_module_notify_exit(struct notifier_block *self,
4547 unsigned long val, void *data)
4551 #endif /* CONFIG_MODULES */
4553 struct notifier_block ftrace_module_exit_nb = {
4554 .notifier_call = ftrace_module_notify_exit,
4555 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4558 void __init ftrace_init(void)
4560 extern unsigned long __start_mcount_loc[];
4561 extern unsigned long __stop_mcount_loc[];
4562 unsigned long count, flags;
4565 local_irq_save(flags);
4566 ret = ftrace_dyn_arch_init();
4567 local_irq_restore(flags);
4571 count = __stop_mcount_loc - __start_mcount_loc;
4573 pr_info("ftrace: No functions to be traced?\n");
4577 pr_info("ftrace: allocating %ld entries in %ld pages\n",
4578 count, count / ENTRIES_PER_PAGE + 1);
4580 last_ftrace_enabled = ftrace_enabled = 1;
4582 ret = ftrace_process_locs(NULL,
4586 ret = register_module_notifier(&ftrace_module_exit_nb);
4588 pr_warning("Failed to register trace ftrace module exit notifier\n");
4590 set_ftrace_early_filters();
4594 ftrace_disabled = 1;
4599 static struct ftrace_ops global_ops = {
4600 .func = ftrace_stub,
4601 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4602 INIT_REGEX_LOCK(global_ops)
4605 static int __init ftrace_nodyn_init(void)
4610 core_initcall(ftrace_nodyn_init);
4612 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4613 static inline void ftrace_startup_enable(int command) { }
4614 /* Keep as macros so we do not need to define the commands */
4615 # define ftrace_startup(ops, command) \
4617 int ___ret = __register_ftrace_function(ops); \
4619 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4622 # define ftrace_shutdown(ops, command) \
4624 int ___ret = __unregister_ftrace_function(ops); \
4626 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
4630 # define ftrace_startup_sysctl() do { } while (0)
4631 # define ftrace_shutdown_sysctl() do { } while (0)
4634 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4639 #endif /* CONFIG_DYNAMIC_FTRACE */
4641 __init void ftrace_init_global_array_ops(struct trace_array *tr)
4643 tr->ops = &global_ops;
4644 tr->ops->private = tr;
4647 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
4649 /* If we filter on pids, update to use the pid function */
4650 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
4651 if (WARN_ON(tr->ops->func != ftrace_stub))
4652 printk("ftrace ops had %pS for function\n",
4654 /* Only the top level instance does pid tracing */
4655 if (!list_empty(&ftrace_pids)) {
4656 set_ftrace_pid_function(func);
4657 func = ftrace_pid_func;
4660 tr->ops->func = func;
4661 tr->ops->private = tr;
4664 void ftrace_reset_array_ops(struct trace_array *tr)
4666 tr->ops->func = ftrace_stub;
4670 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4671 struct ftrace_ops *op, struct pt_regs *regs)
4673 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4677 * Some of the ops may be dynamically allocated,
4678 * they must be freed after a synchronize_sched().
4680 preempt_disable_notrace();
4681 trace_recursion_set(TRACE_CONTROL_BIT);
4684 * Control funcs (perf) uses RCU. Only trace if
4685 * RCU is currently active.
4687 if (!rcu_is_watching())
4690 do_for_each_ftrace_op(op, ftrace_control_list) {
4691 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4692 !ftrace_function_local_disabled(op) &&
4693 ftrace_ops_test(op, ip, regs))
4694 op->func(ip, parent_ip, op, regs);
4695 } while_for_each_ftrace_op(op);
4697 trace_recursion_clear(TRACE_CONTROL_BIT);
4698 preempt_enable_notrace();
4701 static struct ftrace_ops control_ops = {
4702 .func = ftrace_ops_control_func,
4703 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4704 INIT_REGEX_LOCK(control_ops)
4708 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4709 struct ftrace_ops *ignored, struct pt_regs *regs)
4711 struct ftrace_ops *op;
4714 if (function_trace_stop)
4717 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4722 * Some of the ops may be dynamically allocated,
4723 * they must be freed after a synchronize_sched().
4725 preempt_disable_notrace();
4726 do_for_each_ftrace_op(op, ftrace_ops_list) {
4727 if (ftrace_ops_test(op, ip, regs)) {
4728 if (WARN_ON(!op->func)) {
4729 function_trace_stop = 1;
4730 printk("op=%p %pS\n", op, op);
4733 op->func(ip, parent_ip, op, regs);
4735 } while_for_each_ftrace_op(op);
4737 preempt_enable_notrace();
4738 trace_clear_recursion(bit);
4742 * Some archs only support passing ip and parent_ip. Even though
4743 * the list function ignores the op parameter, we do not want any
4744 * C side effects, where a function is called without the caller
4745 * sending a third parameter.
4746 * Archs are to support both the regs and ftrace_ops at the same time.
4747 * If they support ftrace_ops, it is assumed they support regs.
4748 * If call backs want to use regs, they must either check for regs
4749 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4750 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4751 * An architecture can pass partial regs with ftrace_ops and still
4752 * set the ARCH_SUPPORT_FTARCE_OPS.
4754 #if ARCH_SUPPORTS_FTRACE_OPS
4755 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4756 struct ftrace_ops *op, struct pt_regs *regs)
4758 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4761 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4763 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4767 static void clear_ftrace_swapper(void)
4769 struct task_struct *p;
4773 for_each_online_cpu(cpu) {
4775 clear_tsk_trace_trace(p);
4780 static void set_ftrace_swapper(void)
4782 struct task_struct *p;
4786 for_each_online_cpu(cpu) {
4788 set_tsk_trace_trace(p);
4793 static void clear_ftrace_pid(struct pid *pid)
4795 struct task_struct *p;
4798 do_each_pid_task(pid, PIDTYPE_PID, p) {
4799 clear_tsk_trace_trace(p);
4800 } while_each_pid_task(pid, PIDTYPE_PID, p);
4806 static void set_ftrace_pid(struct pid *pid)
4808 struct task_struct *p;
4811 do_each_pid_task(pid, PIDTYPE_PID, p) {
4812 set_tsk_trace_trace(p);
4813 } while_each_pid_task(pid, PIDTYPE_PID, p);
4817 static void clear_ftrace_pid_task(struct pid *pid)
4819 if (pid == ftrace_swapper_pid)
4820 clear_ftrace_swapper();
4822 clear_ftrace_pid(pid);
4825 static void set_ftrace_pid_task(struct pid *pid)
4827 if (pid == ftrace_swapper_pid)
4828 set_ftrace_swapper();
4830 set_ftrace_pid(pid);
4833 static int ftrace_pid_add(int p)
4836 struct ftrace_pid *fpid;
4839 mutex_lock(&ftrace_lock);
4842 pid = ftrace_swapper_pid;
4844 pid = find_get_pid(p);
4851 list_for_each_entry(fpid, &ftrace_pids, list)
4852 if (fpid->pid == pid)
4857 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4861 list_add(&fpid->list, &ftrace_pids);
4864 set_ftrace_pid_task(pid);
4866 ftrace_update_pid_func();
4867 ftrace_startup_enable(0);
4869 mutex_unlock(&ftrace_lock);
4873 if (pid != ftrace_swapper_pid)
4877 mutex_unlock(&ftrace_lock);
4881 static void ftrace_pid_reset(void)
4883 struct ftrace_pid *fpid, *safe;
4885 mutex_lock(&ftrace_lock);
4886 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4887 struct pid *pid = fpid->pid;
4889 clear_ftrace_pid_task(pid);
4891 list_del(&fpid->list);
4895 ftrace_update_pid_func();
4896 ftrace_startup_enable(0);
4898 mutex_unlock(&ftrace_lock);
4901 static void *fpid_start(struct seq_file *m, loff_t *pos)
4903 mutex_lock(&ftrace_lock);
4905 if (list_empty(&ftrace_pids) && (!*pos))
4908 return seq_list_start(&ftrace_pids, *pos);
4911 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4916 return seq_list_next(v, &ftrace_pids, pos);
4919 static void fpid_stop(struct seq_file *m, void *p)
4921 mutex_unlock(&ftrace_lock);
4924 static int fpid_show(struct seq_file *m, void *v)
4926 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4928 if (v == (void *)1) {
4929 seq_printf(m, "no pid\n");
4933 if (fpid->pid == ftrace_swapper_pid)
4934 seq_printf(m, "swapper tasks\n");
4936 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4941 static const struct seq_operations ftrace_pid_sops = {
4942 .start = fpid_start,
4949 ftrace_pid_open(struct inode *inode, struct file *file)
4953 if ((file->f_mode & FMODE_WRITE) &&
4954 (file->f_flags & O_TRUNC))
4957 if (file->f_mode & FMODE_READ)
4958 ret = seq_open(file, &ftrace_pid_sops);
4964 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4965 size_t cnt, loff_t *ppos)
4971 if (cnt >= sizeof(buf))
4974 if (copy_from_user(&buf, ubuf, cnt))
4980 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4981 * to clean the filter quietly.
4983 tmp = strstrip(buf);
4984 if (strlen(tmp) == 0)
4987 ret = kstrtol(tmp, 10, &val);
4991 ret = ftrace_pid_add(val);
4993 return ret ? ret : cnt;
4997 ftrace_pid_release(struct inode *inode, struct file *file)
4999 if (file->f_mode & FMODE_READ)
5000 seq_release(inode, file);
5005 static const struct file_operations ftrace_pid_fops = {
5006 .open = ftrace_pid_open,
5007 .write = ftrace_pid_write,
5009 .llseek = tracing_lseek,
5010 .release = ftrace_pid_release,
5013 static __init int ftrace_init_debugfs(void)
5015 struct dentry *d_tracer;
5017 d_tracer = tracing_init_dentry();
5021 ftrace_init_dyn_debugfs(d_tracer);
5023 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5024 NULL, &ftrace_pid_fops);
5026 ftrace_profile_debugfs(d_tracer);
5030 fs_initcall(ftrace_init_debugfs);
5033 * ftrace_kill - kill ftrace
5035 * This function should be used by panic code. It stops ftrace
5036 * but in a not so nice way. If you need to simply kill ftrace
5037 * from a non-atomic section, use ftrace_kill.
5039 void ftrace_kill(void)
5041 ftrace_disabled = 1;
5043 clear_ftrace_function();
5047 * Test if ftrace is dead or not.
5049 int ftrace_is_dead(void)
5051 return ftrace_disabled;
5055 * register_ftrace_function - register a function for profiling
5056 * @ops - ops structure that holds the function for profiling.
5058 * Register a function to be called by all functions in the
5061 * Note: @ops->func and all the functions it calls must be labeled
5062 * with "notrace", otherwise it will go into a
5065 int register_ftrace_function(struct ftrace_ops *ops)
5069 ftrace_ops_init(ops);
5071 mutex_lock(&ftrace_lock);
5073 ret = ftrace_startup(ops, 0);
5075 mutex_unlock(&ftrace_lock);
5079 EXPORT_SYMBOL_GPL(register_ftrace_function);
5082 * unregister_ftrace_function - unregister a function for profiling.
5083 * @ops - ops structure that holds the function to unregister
5085 * Unregister a function that was added to be called by ftrace profiling.
5087 int unregister_ftrace_function(struct ftrace_ops *ops)
5091 mutex_lock(&ftrace_lock);
5092 ret = ftrace_shutdown(ops, 0);
5093 mutex_unlock(&ftrace_lock);
5097 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5100 ftrace_enable_sysctl(struct ctl_table *table, int write,
5101 void __user *buffer, size_t *lenp,
5106 mutex_lock(&ftrace_lock);
5108 if (unlikely(ftrace_disabled))
5111 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5113 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5116 last_ftrace_enabled = !!ftrace_enabled;
5118 if (ftrace_enabled) {
5120 ftrace_startup_sysctl();
5122 /* we are starting ftrace again */
5123 if (ftrace_ops_list != &ftrace_list_end)
5124 update_ftrace_function();
5127 /* stopping ftrace calls (just send to ftrace_stub) */
5128 ftrace_trace_function = ftrace_stub;
5130 ftrace_shutdown_sysctl();
5134 mutex_unlock(&ftrace_lock);
5138 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5140 static int ftrace_graph_active;
5142 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5147 /* The callbacks that hook a function */
5148 trace_func_graph_ret_t ftrace_graph_return =
5149 (trace_func_graph_ret_t)ftrace_stub;
5150 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5151 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5153 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5154 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5158 unsigned long flags;
5159 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5160 struct task_struct *g, *t;
5162 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5163 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5164 * sizeof(struct ftrace_ret_stack),
5166 if (!ret_stack_list[i]) {
5174 read_lock_irqsave(&tasklist_lock, flags);
5175 do_each_thread(g, t) {
5181 if (t->ret_stack == NULL) {
5182 atomic_set(&t->tracing_graph_pause, 0);
5183 atomic_set(&t->trace_overrun, 0);
5184 t->curr_ret_stack = -1;
5185 /* Make sure the tasks see the -1 first: */
5187 t->ret_stack = ret_stack_list[start++];
5189 } while_each_thread(g, t);
5192 read_unlock_irqrestore(&tasklist_lock, flags);
5194 for (i = start; i < end; i++)
5195 kfree(ret_stack_list[i]);
5200 ftrace_graph_probe_sched_switch(void *ignore,
5201 struct task_struct *prev, struct task_struct *next)
5203 unsigned long long timestamp;
5207 * Does the user want to count the time a function was asleep.
5208 * If so, do not update the time stamps.
5210 if (trace_flags & TRACE_ITER_SLEEP_TIME)
5213 timestamp = trace_clock_local();
5215 prev->ftrace_timestamp = timestamp;
5217 /* only process tasks that we timestamped */
5218 if (!next->ftrace_timestamp)
5222 * Update all the counters in next to make up for the
5223 * time next was sleeping.
5225 timestamp -= next->ftrace_timestamp;
5227 for (index = next->curr_ret_stack; index >= 0; index--)
5228 next->ret_stack[index].calltime += timestamp;
5231 /* Allocate a return stack for each task */
5232 static int start_graph_tracing(void)
5234 struct ftrace_ret_stack **ret_stack_list;
5237 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5238 sizeof(struct ftrace_ret_stack *),
5241 if (!ret_stack_list)
5244 /* The cpu_boot init_task->ret_stack will never be freed */
5245 for_each_online_cpu(cpu) {
5246 if (!idle_task(cpu)->ret_stack)
5247 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5251 ret = alloc_retstack_tasklist(ret_stack_list);
5252 } while (ret == -EAGAIN);
5255 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5257 pr_info("ftrace_graph: Couldn't activate tracepoint"
5258 " probe to kernel_sched_switch\n");
5261 kfree(ret_stack_list);
5266 * Hibernation protection.
5267 * The state of the current task is too much unstable during
5268 * suspend/restore to disk. We want to protect against that.
5271 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5275 case PM_HIBERNATION_PREPARE:
5276 pause_graph_tracing();
5279 case PM_POST_HIBERNATION:
5280 unpause_graph_tracing();
5286 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5288 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5290 return __ftrace_graph_entry(trace);
5294 * The function graph tracer should only trace the functions defined
5295 * by set_ftrace_filter and set_ftrace_notrace. If another function
5296 * tracer ops is registered, the graph tracer requires testing the
5297 * function against the global ops, and not just trace any function
5298 * that any ftrace_ops registered.
5300 static void update_function_graph_func(void)
5302 if (ftrace_ops_list == &ftrace_list_end ||
5303 (ftrace_ops_list == &global_ops &&
5304 global_ops.next == &ftrace_list_end))
5305 ftrace_graph_entry = __ftrace_graph_entry;
5307 ftrace_graph_entry = ftrace_graph_entry_test;
5310 static struct notifier_block ftrace_suspend_notifier = {
5311 .notifier_call = ftrace_suspend_notifier_call,
5314 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5315 trace_func_graph_ent_t entryfunc)
5319 mutex_lock(&ftrace_lock);
5321 /* we currently allow only one tracer registered at a time */
5322 if (ftrace_graph_active) {
5327 register_pm_notifier(&ftrace_suspend_notifier);
5329 ftrace_graph_active++;
5330 ret = start_graph_tracing();
5332 ftrace_graph_active--;
5336 ftrace_graph_return = retfunc;
5339 * Update the indirect function to the entryfunc, and the
5340 * function that gets called to the entry_test first. Then
5341 * call the update fgraph entry function to determine if
5342 * the entryfunc should be called directly or not.
5344 __ftrace_graph_entry = entryfunc;
5345 ftrace_graph_entry = ftrace_graph_entry_test;
5346 update_function_graph_func();
5348 /* Function graph doesn't use the .func field of global_ops */
5349 global_ops.flags |= FTRACE_OPS_FL_STUB;
5351 #ifdef CONFIG_DYNAMIC_FTRACE
5352 /* Optimize function graph calling (if implemented by arch) */
5353 global_ops.trampoline = FTRACE_GRAPH_ADDR;
5356 ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
5359 mutex_unlock(&ftrace_lock);
5363 void unregister_ftrace_graph(void)
5365 mutex_lock(&ftrace_lock);
5367 if (unlikely(!ftrace_graph_active))
5370 ftrace_graph_active--;
5371 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5372 ftrace_graph_entry = ftrace_graph_entry_stub;
5373 __ftrace_graph_entry = ftrace_graph_entry_stub;
5374 ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
5375 global_ops.flags &= ~FTRACE_OPS_FL_STUB;
5376 #ifdef CONFIG_DYNAMIC_FTRACE
5377 global_ops.trampoline = 0;
5379 unregister_pm_notifier(&ftrace_suspend_notifier);
5380 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5383 mutex_unlock(&ftrace_lock);
5386 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5389 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5391 atomic_set(&t->tracing_graph_pause, 0);
5392 atomic_set(&t->trace_overrun, 0);
5393 t->ftrace_timestamp = 0;
5394 /* make curr_ret_stack visible before we add the ret_stack */
5396 t->ret_stack = ret_stack;
5400 * Allocate a return stack for the idle task. May be the first
5401 * time through, or it may be done by CPU hotplug online.
5403 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5405 t->curr_ret_stack = -1;
5407 * The idle task has no parent, it either has its own
5408 * stack or no stack at all.
5411 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5413 if (ftrace_graph_active) {
5414 struct ftrace_ret_stack *ret_stack;
5416 ret_stack = per_cpu(idle_ret_stack, cpu);
5418 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5419 * sizeof(struct ftrace_ret_stack),
5423 per_cpu(idle_ret_stack, cpu) = ret_stack;
5425 graph_init_task(t, ret_stack);
5429 /* Allocate a return stack for newly created task */
5430 void ftrace_graph_init_task(struct task_struct *t)
5432 /* Make sure we do not use the parent ret_stack */
5433 t->ret_stack = NULL;
5434 t->curr_ret_stack = -1;
5436 if (ftrace_graph_active) {
5437 struct ftrace_ret_stack *ret_stack;
5439 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5440 * sizeof(struct ftrace_ret_stack),
5444 graph_init_task(t, ret_stack);
5448 void ftrace_graph_exit_task(struct task_struct *t)
5450 struct ftrace_ret_stack *ret_stack = t->ret_stack;
5452 t->ret_stack = NULL;
5453 /* NULL must become visible to IRQs before we free it: */
5459 void ftrace_graph_stop(void)