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_GLOBAL | 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_global_list __read_mostly = &ftrace_list_end;
107 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
108 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
109 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
110 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
111 static struct ftrace_ops global_ops;
112 static struct ftrace_ops control_ops;
114 #if ARCH_SUPPORTS_FTRACE_OPS
115 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
116 struct ftrace_ops *op, struct pt_regs *regs);
118 /* See comment below, where ftrace_ops_list_func is defined */
119 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
120 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
124 * Traverse the ftrace_global_list, invoking all entries. The reason that we
125 * can use rcu_dereference_raw_notrace() is that elements removed from this list
126 * are simply leaked, so there is no need to interact with a grace-period
127 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
128 * concurrent insertions into the ftrace_global_list.
130 * Silly Alpha and silly pointer-speculation compiler optimizations!
132 #define do_for_each_ftrace_op(op, list) \
133 op = rcu_dereference_raw_notrace(list); \
137 * Optimized for just a single item in the list (as that is the normal case).
139 #define while_for_each_ftrace_op(op) \
140 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
141 unlikely((op) != &ftrace_list_end))
143 static inline void ftrace_ops_init(struct ftrace_ops *ops)
145 #ifdef CONFIG_DYNAMIC_FTRACE
146 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
147 mutex_init(&ops->regex_lock);
148 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
154 * ftrace_nr_registered_ops - return number of ops registered
156 * Returns the number of ftrace_ops registered and tracing functions
158 int ftrace_nr_registered_ops(void)
160 struct ftrace_ops *ops;
163 mutex_lock(&ftrace_lock);
165 for (ops = ftrace_ops_list;
166 ops != &ftrace_list_end; ops = ops->next)
169 mutex_unlock(&ftrace_lock);
175 ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
176 struct ftrace_ops *op, struct pt_regs *regs)
180 bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
184 do_for_each_ftrace_op(op, ftrace_global_list) {
185 op->func(ip, parent_ip, op, regs);
186 } while_for_each_ftrace_op(op);
188 trace_clear_recursion(bit);
191 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
192 struct ftrace_ops *op, struct pt_regs *regs)
194 if (!test_tsk_trace_trace(current))
197 ftrace_pid_function(ip, parent_ip, op, regs);
200 static void set_ftrace_pid_function(ftrace_func_t func)
202 /* do not set ftrace_pid_function to itself! */
203 if (func != ftrace_pid_func)
204 ftrace_pid_function = func;
208 * clear_ftrace_function - reset the ftrace function
210 * This NULLs the ftrace function and in essence stops
211 * tracing. There may be lag
213 void clear_ftrace_function(void)
215 ftrace_trace_function = ftrace_stub;
216 ftrace_pid_function = ftrace_stub;
219 static void control_ops_disable_all(struct ftrace_ops *ops)
223 for_each_possible_cpu(cpu)
224 *per_cpu_ptr(ops->disabled, cpu) = 1;
227 static int control_ops_alloc(struct ftrace_ops *ops)
229 int __percpu *disabled;
231 disabled = alloc_percpu(int);
235 ops->disabled = disabled;
236 control_ops_disable_all(ops);
240 static void control_ops_free(struct ftrace_ops *ops)
242 free_percpu(ops->disabled);
245 static void update_global_ops(void)
247 ftrace_func_t func = ftrace_global_list_func;
248 void *private = NULL;
250 /* The list has its own recursion protection. */
251 global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
254 * If there's only one function registered, then call that
255 * function directly. Otherwise, we need to iterate over the
256 * registered callers.
258 if (ftrace_global_list == &ftrace_list_end ||
259 ftrace_global_list->next == &ftrace_list_end) {
260 func = ftrace_global_list->func;
261 private = ftrace_global_list->private;
263 * As we are calling the function directly.
264 * If it does not have recursion protection,
265 * the function_trace_op needs to be updated
268 if (!(ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE))
269 global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
272 /* If we filter on pids, update to use the pid function */
273 if (!list_empty(&ftrace_pids)) {
274 set_ftrace_pid_function(func);
275 func = ftrace_pid_func;
278 global_ops.func = func;
279 global_ops.private = private;
282 static void ftrace_sync(struct work_struct *work)
285 * This function is just a stub to implement a hard force
286 * of synchronize_sched(). This requires synchronizing
287 * tasks even in userspace and idle.
289 * Yes, function tracing is rude.
293 static void ftrace_sync_ipi(void *data)
295 /* Probably not needed, but do it anyway */
299 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
300 static void update_function_graph_func(void);
302 static inline void update_function_graph_func(void) { }
305 static void update_ftrace_function(void)
312 * If we are at the end of the list and this ops is
313 * recursion safe and not dynamic and the arch supports passing ops,
314 * then have the mcount trampoline call the function directly.
316 if (ftrace_ops_list == &ftrace_list_end ||
317 (ftrace_ops_list->next == &ftrace_list_end &&
318 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
319 (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
320 !FTRACE_FORCE_LIST_FUNC)) {
321 /* Set the ftrace_ops that the arch callback uses */
322 if (ftrace_ops_list == &global_ops)
323 set_function_trace_op = ftrace_global_list;
325 set_function_trace_op = ftrace_ops_list;
326 func = ftrace_ops_list->func;
328 /* Just use the default ftrace_ops */
329 set_function_trace_op = &ftrace_list_end;
330 func = ftrace_ops_list_func;
333 /* If there's no change, then do nothing more here */
334 if (ftrace_trace_function == func)
337 update_function_graph_func();
340 * If we are using the list function, it doesn't care
341 * about the function_trace_ops.
343 if (func == ftrace_ops_list_func) {
344 ftrace_trace_function = func;
346 * Don't even bother setting function_trace_ops,
347 * it would be racy to do so anyway.
352 #ifndef CONFIG_DYNAMIC_FTRACE
354 * For static tracing, we need to be a bit more careful.
355 * The function change takes affect immediately. Thus,
356 * we need to coorditate the setting of the function_trace_ops
357 * with the setting of the ftrace_trace_function.
359 * Set the function to the list ops, which will call the
360 * function we want, albeit indirectly, but it handles the
361 * ftrace_ops and doesn't depend on function_trace_op.
363 ftrace_trace_function = ftrace_ops_list_func;
365 * Make sure all CPUs see this. Yes this is slow, but static
366 * tracing is slow and nasty to have enabled.
368 schedule_on_each_cpu(ftrace_sync);
369 /* Now all cpus are using the list ops. */
370 function_trace_op = set_function_trace_op;
371 /* Make sure the function_trace_op is visible on all CPUs */
373 /* Nasty way to force a rmb on all cpus */
374 smp_call_function(ftrace_sync_ipi, NULL, 1);
375 /* OK, we are all set to update the ftrace_trace_function now! */
376 #endif /* !CONFIG_DYNAMIC_FTRACE */
378 ftrace_trace_function = func;
381 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
385 * We are entering ops into the list but another
386 * CPU might be walking that list. We need to make sure
387 * the ops->next pointer is valid before another CPU sees
388 * the ops pointer included into the list.
390 rcu_assign_pointer(*list, ops);
393 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
395 struct ftrace_ops **p;
398 * If we are removing the last function, then simply point
399 * to the ftrace_stub.
401 if (*list == ops && ops->next == &ftrace_list_end) {
402 *list = &ftrace_list_end;
406 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
417 static void add_ftrace_list_ops(struct ftrace_ops **list,
418 struct ftrace_ops *main_ops,
419 struct ftrace_ops *ops)
421 int first = *list == &ftrace_list_end;
422 add_ftrace_ops(list, ops);
424 add_ftrace_ops(&ftrace_ops_list, main_ops);
427 static int remove_ftrace_list_ops(struct ftrace_ops **list,
428 struct ftrace_ops *main_ops,
429 struct ftrace_ops *ops)
431 int ret = remove_ftrace_ops(list, ops);
432 if (!ret && *list == &ftrace_list_end)
433 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
437 static int __register_ftrace_function(struct ftrace_ops *ops)
439 if (ops->flags & FTRACE_OPS_FL_DELETED)
442 if (FTRACE_WARN_ON(ops == &global_ops))
445 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
448 /* We don't support both control and global flags set. */
449 if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
452 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
454 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
455 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
456 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
458 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
459 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
462 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
463 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
466 if (!core_kernel_data((unsigned long)ops))
467 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
469 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
470 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
471 ops->flags |= FTRACE_OPS_FL_ENABLED;
472 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
473 if (control_ops_alloc(ops))
475 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
477 add_ftrace_ops(&ftrace_ops_list, ops);
480 update_ftrace_function();
485 static int __unregister_ftrace_function(struct ftrace_ops *ops)
489 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
492 if (FTRACE_WARN_ON(ops == &global_ops))
495 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
496 ret = remove_ftrace_list_ops(&ftrace_global_list,
499 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
500 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
501 ret = remove_ftrace_list_ops(&ftrace_control_list,
504 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
510 update_ftrace_function();
515 static void ftrace_update_pid_func(void)
517 /* Only do something if we are tracing something */
518 if (ftrace_trace_function == ftrace_stub)
521 update_ftrace_function();
524 #ifdef CONFIG_FUNCTION_PROFILER
525 struct ftrace_profile {
526 struct hlist_node node;
528 unsigned long counter;
529 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
530 unsigned long long time;
531 unsigned long long time_squared;
535 struct ftrace_profile_page {
536 struct ftrace_profile_page *next;
538 struct ftrace_profile records[];
541 struct ftrace_profile_stat {
543 struct hlist_head *hash;
544 struct ftrace_profile_page *pages;
545 struct ftrace_profile_page *start;
546 struct tracer_stat stat;
549 #define PROFILE_RECORDS_SIZE \
550 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
552 #define PROFILES_PER_PAGE \
553 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
555 static int ftrace_profile_enabled __read_mostly;
557 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
558 static DEFINE_MUTEX(ftrace_profile_lock);
560 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
562 #define FTRACE_PROFILE_HASH_BITS 10
563 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
566 function_stat_next(void *v, int idx)
568 struct ftrace_profile *rec = v;
569 struct ftrace_profile_page *pg;
571 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
577 if ((void *)rec >= (void *)&pg->records[pg->index]) {
581 rec = &pg->records[0];
589 static void *function_stat_start(struct tracer_stat *trace)
591 struct ftrace_profile_stat *stat =
592 container_of(trace, struct ftrace_profile_stat, stat);
594 if (!stat || !stat->start)
597 return function_stat_next(&stat->start->records[0], 0);
600 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
601 /* function graph compares on total time */
602 static int function_stat_cmp(void *p1, void *p2)
604 struct ftrace_profile *a = p1;
605 struct ftrace_profile *b = p2;
607 if (a->time < b->time)
609 if (a->time > b->time)
615 /* not function graph compares against hits */
616 static int function_stat_cmp(void *p1, void *p2)
618 struct ftrace_profile *a = p1;
619 struct ftrace_profile *b = p2;
621 if (a->counter < b->counter)
623 if (a->counter > b->counter)
630 static int function_stat_headers(struct seq_file *m)
632 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
633 seq_printf(m, " Function "
636 "--- ---- --- ---\n");
638 seq_printf(m, " Function Hit\n"
644 static int function_stat_show(struct seq_file *m, void *v)
646 struct ftrace_profile *rec = v;
647 char str[KSYM_SYMBOL_LEN];
649 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
650 static struct trace_seq s;
651 unsigned long long avg;
652 unsigned long long stddev;
654 mutex_lock(&ftrace_profile_lock);
656 /* we raced with function_profile_reset() */
657 if (unlikely(rec->counter == 0)) {
662 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
663 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
665 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
668 do_div(avg, rec->counter);
670 /* Sample standard deviation (s^2) */
671 if (rec->counter <= 1)
675 * Apply Welford's method:
676 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
678 stddev = rec->counter * rec->time_squared -
679 rec->time * rec->time;
682 * Divide only 1000 for ns^2 -> us^2 conversion.
683 * trace_print_graph_duration will divide 1000 again.
685 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
689 trace_print_graph_duration(rec->time, &s);
690 trace_seq_puts(&s, " ");
691 trace_print_graph_duration(avg, &s);
692 trace_seq_puts(&s, " ");
693 trace_print_graph_duration(stddev, &s);
694 trace_print_seq(m, &s);
698 mutex_unlock(&ftrace_profile_lock);
703 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
705 struct ftrace_profile_page *pg;
707 pg = stat->pages = stat->start;
710 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
715 memset(stat->hash, 0,
716 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
719 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
721 struct ftrace_profile_page *pg;
726 /* If we already allocated, do nothing */
730 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
734 #ifdef CONFIG_DYNAMIC_FTRACE
735 functions = ftrace_update_tot_cnt;
738 * We do not know the number of functions that exist because
739 * dynamic tracing is what counts them. With past experience
740 * we have around 20K functions. That should be more than enough.
741 * It is highly unlikely we will execute every function in
747 pg = stat->start = stat->pages;
749 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
751 for (i = 1; i < pages; i++) {
752 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
763 unsigned long tmp = (unsigned long)pg;
775 static int ftrace_profile_init_cpu(int cpu)
777 struct ftrace_profile_stat *stat;
780 stat = &per_cpu(ftrace_profile_stats, cpu);
783 /* If the profile is already created, simply reset it */
784 ftrace_profile_reset(stat);
789 * We are profiling all functions, but usually only a few thousand
790 * functions are hit. We'll make a hash of 1024 items.
792 size = FTRACE_PROFILE_HASH_SIZE;
794 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
799 /* Preallocate the function profiling pages */
800 if (ftrace_profile_pages_init(stat) < 0) {
809 static int ftrace_profile_init(void)
814 for_each_possible_cpu(cpu) {
815 ret = ftrace_profile_init_cpu(cpu);
823 /* interrupts must be disabled */
824 static struct ftrace_profile *
825 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
827 struct ftrace_profile *rec;
828 struct hlist_head *hhd;
831 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
832 hhd = &stat->hash[key];
834 if (hlist_empty(hhd))
837 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
845 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
846 struct ftrace_profile *rec)
850 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
851 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
855 * The memory is already allocated, this simply finds a new record to use.
857 static struct ftrace_profile *
858 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
860 struct ftrace_profile *rec = NULL;
862 /* prevent recursion (from NMIs) */
863 if (atomic_inc_return(&stat->disabled) != 1)
867 * Try to find the function again since an NMI
868 * could have added it
870 rec = ftrace_find_profiled_func(stat, ip);
874 if (stat->pages->index == PROFILES_PER_PAGE) {
875 if (!stat->pages->next)
877 stat->pages = stat->pages->next;
880 rec = &stat->pages->records[stat->pages->index++];
882 ftrace_add_profile(stat, rec);
885 atomic_dec(&stat->disabled);
891 function_profile_call(unsigned long ip, unsigned long parent_ip,
892 struct ftrace_ops *ops, struct pt_regs *regs)
894 struct ftrace_profile_stat *stat;
895 struct ftrace_profile *rec;
898 if (!ftrace_profile_enabled)
901 local_irq_save(flags);
903 stat = &__get_cpu_var(ftrace_profile_stats);
904 if (!stat->hash || !ftrace_profile_enabled)
907 rec = ftrace_find_profiled_func(stat, ip);
909 rec = ftrace_profile_alloc(stat, ip);
916 local_irq_restore(flags);
919 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
920 static int profile_graph_entry(struct ftrace_graph_ent *trace)
922 function_profile_call(trace->func, 0, NULL, NULL);
926 static void profile_graph_return(struct ftrace_graph_ret *trace)
928 struct ftrace_profile_stat *stat;
929 unsigned long long calltime;
930 struct ftrace_profile *rec;
933 local_irq_save(flags);
934 stat = &__get_cpu_var(ftrace_profile_stats);
935 if (!stat->hash || !ftrace_profile_enabled)
938 /* If the calltime was zero'd ignore it */
939 if (!trace->calltime)
942 calltime = trace->rettime - trace->calltime;
944 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
947 index = trace->depth;
949 /* Append this call time to the parent time to subtract */
951 current->ret_stack[index - 1].subtime += calltime;
953 if (current->ret_stack[index].subtime < calltime)
954 calltime -= current->ret_stack[index].subtime;
959 rec = ftrace_find_profiled_func(stat, trace->func);
961 rec->time += calltime;
962 rec->time_squared += calltime * calltime;
966 local_irq_restore(flags);
969 static int register_ftrace_profiler(void)
971 return register_ftrace_graph(&profile_graph_return,
972 &profile_graph_entry);
975 static void unregister_ftrace_profiler(void)
977 unregister_ftrace_graph();
980 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
981 .func = function_profile_call,
982 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
983 INIT_REGEX_LOCK(ftrace_profile_ops)
986 static int register_ftrace_profiler(void)
988 return register_ftrace_function(&ftrace_profile_ops);
991 static void unregister_ftrace_profiler(void)
993 unregister_ftrace_function(&ftrace_profile_ops);
995 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
998 ftrace_profile_write(struct file *filp, const char __user *ubuf,
999 size_t cnt, loff_t *ppos)
1004 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1010 mutex_lock(&ftrace_profile_lock);
1011 if (ftrace_profile_enabled ^ val) {
1013 ret = ftrace_profile_init();
1019 ret = register_ftrace_profiler();
1024 ftrace_profile_enabled = 1;
1026 ftrace_profile_enabled = 0;
1028 * unregister_ftrace_profiler calls stop_machine
1029 * so this acts like an synchronize_sched.
1031 unregister_ftrace_profiler();
1035 mutex_unlock(&ftrace_profile_lock);
1043 ftrace_profile_read(struct file *filp, char __user *ubuf,
1044 size_t cnt, loff_t *ppos)
1046 char buf[64]; /* big enough to hold a number */
1049 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1050 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1053 static const struct file_operations ftrace_profile_fops = {
1054 .open = tracing_open_generic,
1055 .read = ftrace_profile_read,
1056 .write = ftrace_profile_write,
1057 .llseek = default_llseek,
1060 /* used to initialize the real stat files */
1061 static struct tracer_stat function_stats __initdata = {
1062 .name = "functions",
1063 .stat_start = function_stat_start,
1064 .stat_next = function_stat_next,
1065 .stat_cmp = function_stat_cmp,
1066 .stat_headers = function_stat_headers,
1067 .stat_show = function_stat_show
1070 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1072 struct ftrace_profile_stat *stat;
1073 struct dentry *entry;
1078 for_each_possible_cpu(cpu) {
1079 stat = &per_cpu(ftrace_profile_stats, cpu);
1081 /* allocate enough for function name + cpu number */
1082 name = kmalloc(32, GFP_KERNEL);
1085 * The files created are permanent, if something happens
1086 * we still do not free memory.
1089 "Could not allocate stat file for cpu %d\n",
1093 stat->stat = function_stats;
1094 snprintf(name, 32, "function%d", cpu);
1095 stat->stat.name = name;
1096 ret = register_stat_tracer(&stat->stat);
1099 "Could not register function stat for cpu %d\n",
1106 entry = debugfs_create_file("function_profile_enabled", 0644,
1107 d_tracer, NULL, &ftrace_profile_fops);
1109 pr_warning("Could not create debugfs "
1110 "'function_profile_enabled' entry\n");
1113 #else /* CONFIG_FUNCTION_PROFILER */
1114 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1117 #endif /* CONFIG_FUNCTION_PROFILER */
1119 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1121 #ifdef CONFIG_DYNAMIC_FTRACE
1123 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1124 # error Dynamic ftrace depends on MCOUNT_RECORD
1127 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1129 struct ftrace_func_probe {
1130 struct hlist_node node;
1131 struct ftrace_probe_ops *ops;
1132 unsigned long flags;
1135 struct list_head free_list;
1138 struct ftrace_func_entry {
1139 struct hlist_node hlist;
1143 struct ftrace_hash {
1144 unsigned long size_bits;
1145 struct hlist_head *buckets;
1146 unsigned long count;
1147 struct rcu_head rcu;
1151 * We make these constant because no one should touch them,
1152 * but they are used as the default "empty hash", to avoid allocating
1153 * it all the time. These are in a read only section such that if
1154 * anyone does try to modify it, it will cause an exception.
1156 static const struct hlist_head empty_buckets[1];
1157 static const struct ftrace_hash empty_hash = {
1158 .buckets = (struct hlist_head *)empty_buckets,
1160 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1162 static struct ftrace_ops global_ops = {
1163 .func = ftrace_stub,
1164 .notrace_hash = EMPTY_HASH,
1165 .filter_hash = EMPTY_HASH,
1166 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1167 INIT_REGEX_LOCK(global_ops)
1170 struct ftrace_page {
1171 struct ftrace_page *next;
1172 struct dyn_ftrace *records;
1177 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1178 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1180 /* estimate from running different kernels */
1181 #define NR_TO_INIT 10000
1183 static struct ftrace_page *ftrace_pages_start;
1184 static struct ftrace_page *ftrace_pages;
1186 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1188 return !hash || !hash->count;
1191 static struct ftrace_func_entry *
1192 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1195 struct ftrace_func_entry *entry;
1196 struct hlist_head *hhd;
1198 if (ftrace_hash_empty(hash))
1201 if (hash->size_bits > 0)
1202 key = hash_long(ip, hash->size_bits);
1206 hhd = &hash->buckets[key];
1208 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1209 if (entry->ip == ip)
1215 static void __add_hash_entry(struct ftrace_hash *hash,
1216 struct ftrace_func_entry *entry)
1218 struct hlist_head *hhd;
1221 if (hash->size_bits)
1222 key = hash_long(entry->ip, hash->size_bits);
1226 hhd = &hash->buckets[key];
1227 hlist_add_head(&entry->hlist, hhd);
1231 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1233 struct ftrace_func_entry *entry;
1235 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1240 __add_hash_entry(hash, entry);
1246 free_hash_entry(struct ftrace_hash *hash,
1247 struct ftrace_func_entry *entry)
1249 hlist_del(&entry->hlist);
1255 remove_hash_entry(struct ftrace_hash *hash,
1256 struct ftrace_func_entry *entry)
1258 hlist_del(&entry->hlist);
1262 static void ftrace_hash_clear(struct ftrace_hash *hash)
1264 struct hlist_head *hhd;
1265 struct hlist_node *tn;
1266 struct ftrace_func_entry *entry;
1267 int size = 1 << hash->size_bits;
1273 for (i = 0; i < size; i++) {
1274 hhd = &hash->buckets[i];
1275 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1276 free_hash_entry(hash, entry);
1278 FTRACE_WARN_ON(hash->count);
1281 static void free_ftrace_hash(struct ftrace_hash *hash)
1283 if (!hash || hash == EMPTY_HASH)
1285 ftrace_hash_clear(hash);
1286 kfree(hash->buckets);
1290 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1292 struct ftrace_hash *hash;
1294 hash = container_of(rcu, struct ftrace_hash, rcu);
1295 free_ftrace_hash(hash);
1298 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1300 if (!hash || hash == EMPTY_HASH)
1302 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1305 void ftrace_free_filter(struct ftrace_ops *ops)
1307 ftrace_ops_init(ops);
1308 free_ftrace_hash(ops->filter_hash);
1309 free_ftrace_hash(ops->notrace_hash);
1312 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1314 struct ftrace_hash *hash;
1317 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1321 size = 1 << size_bits;
1322 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1324 if (!hash->buckets) {
1329 hash->size_bits = size_bits;
1334 static struct ftrace_hash *
1335 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1337 struct ftrace_func_entry *entry;
1338 struct ftrace_hash *new_hash;
1343 new_hash = alloc_ftrace_hash(size_bits);
1348 if (ftrace_hash_empty(hash))
1351 size = 1 << hash->size_bits;
1352 for (i = 0; i < size; i++) {
1353 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1354 ret = add_hash_entry(new_hash, entry->ip);
1360 FTRACE_WARN_ON(new_hash->count != hash->count);
1365 free_ftrace_hash(new_hash);
1370 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1372 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1375 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1376 struct ftrace_hash **dst, struct ftrace_hash *src)
1378 struct ftrace_func_entry *entry;
1379 struct hlist_node *tn;
1380 struct hlist_head *hhd;
1381 struct ftrace_hash *old_hash;
1382 struct ftrace_hash *new_hash;
1383 int size = src->count;
1389 * Remove the current set, update the hash and add
1392 ftrace_hash_rec_disable(ops, enable);
1395 * If the new source is empty, just free dst and assign it
1399 free_ftrace_hash_rcu(*dst);
1400 rcu_assign_pointer(*dst, EMPTY_HASH);
1401 /* still need to update the function records */
1407 * Make the hash size about 1/2 the # found
1409 for (size /= 2; size; size >>= 1)
1412 /* Don't allocate too much */
1413 if (bits > FTRACE_HASH_MAX_BITS)
1414 bits = FTRACE_HASH_MAX_BITS;
1417 new_hash = alloc_ftrace_hash(bits);
1421 size = 1 << src->size_bits;
1422 for (i = 0; i < size; i++) {
1423 hhd = &src->buckets[i];
1424 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1425 remove_hash_entry(src, entry);
1426 __add_hash_entry(new_hash, entry);
1431 rcu_assign_pointer(*dst, new_hash);
1432 free_ftrace_hash_rcu(old_hash);
1437 * Enable regardless of ret:
1438 * On success, we enable the new hash.
1439 * On failure, we re-enable the original hash.
1441 ftrace_hash_rec_enable(ops, enable);
1447 * Test the hashes for this ops to see if we want to call
1448 * the ops->func or not.
1450 * It's a match if the ip is in the ops->filter_hash or
1451 * the filter_hash does not exist or is empty,
1453 * the ip is not in the ops->notrace_hash.
1455 * This needs to be called with preemption disabled as
1456 * the hashes are freed with call_rcu_sched().
1459 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1461 struct ftrace_hash *filter_hash;
1462 struct ftrace_hash *notrace_hash;
1465 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1467 * There's a small race when adding ops that the ftrace handler
1468 * that wants regs, may be called without them. We can not
1469 * allow that handler to be called if regs is NULL.
1471 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1475 filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1476 notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1478 if ((ftrace_hash_empty(filter_hash) ||
1479 ftrace_lookup_ip(filter_hash, ip)) &&
1480 (ftrace_hash_empty(notrace_hash) ||
1481 !ftrace_lookup_ip(notrace_hash, ip)))
1490 * This is a double for. Do not use 'break' to break out of the loop,
1491 * you must use a goto.
1493 #define do_for_each_ftrace_rec(pg, rec) \
1494 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1496 for (_____i = 0; _____i < pg->index; _____i++) { \
1497 rec = &pg->records[_____i];
1499 #define while_for_each_ftrace_rec() \
1504 static int ftrace_cmp_recs(const void *a, const void *b)
1506 const struct dyn_ftrace *key = a;
1507 const struct dyn_ftrace *rec = b;
1509 if (key->flags < rec->ip)
1511 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1516 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1518 struct ftrace_page *pg;
1519 struct dyn_ftrace *rec;
1520 struct dyn_ftrace key;
1523 key.flags = end; /* overload flags, as it is unsigned long */
1525 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1526 if (end < pg->records[0].ip ||
1527 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1529 rec = bsearch(&key, pg->records, pg->index,
1530 sizeof(struct dyn_ftrace),
1540 * ftrace_location - return true if the ip giving is a traced location
1541 * @ip: the instruction pointer to check
1543 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1544 * That is, the instruction that is either a NOP or call to
1545 * the function tracer. It checks the ftrace internal tables to
1546 * determine if the address belongs or not.
1548 unsigned long ftrace_location(unsigned long ip)
1550 return ftrace_location_range(ip, ip);
1554 * ftrace_text_reserved - return true if range contains an ftrace location
1555 * @start: start of range to search
1556 * @end: end of range to search (inclusive). @end points to the last byte to check.
1558 * Returns 1 if @start and @end contains a ftrace location.
1559 * That is, the instruction that is either a NOP or call to
1560 * the function tracer. It checks the ftrace internal tables to
1561 * determine if the address belongs or not.
1563 int ftrace_text_reserved(void *start, void *end)
1567 ret = ftrace_location_range((unsigned long)start,
1568 (unsigned long)end);
1573 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1577 struct ftrace_hash *hash;
1578 struct ftrace_hash *other_hash;
1579 struct ftrace_page *pg;
1580 struct dyn_ftrace *rec;
1584 /* Only update if the ops has been registered */
1585 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1589 * In the filter_hash case:
1590 * If the count is zero, we update all records.
1591 * Otherwise we just update the items in the hash.
1593 * In the notrace_hash case:
1594 * We enable the update in the hash.
1595 * As disabling notrace means enabling the tracing,
1596 * and enabling notrace means disabling, the inc variable
1600 hash = ops->filter_hash;
1601 other_hash = ops->notrace_hash;
1602 if (ftrace_hash_empty(hash))
1606 hash = ops->notrace_hash;
1607 other_hash = ops->filter_hash;
1609 * If the notrace hash has no items,
1610 * then there's nothing to do.
1612 if (ftrace_hash_empty(hash))
1616 do_for_each_ftrace_rec(pg, rec) {
1617 int in_other_hash = 0;
1623 * Only the filter_hash affects all records.
1624 * Update if the record is not in the notrace hash.
1626 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1629 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1630 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1635 if (filter_hash && in_hash && !in_other_hash)
1637 else if (!filter_hash && in_hash &&
1638 (in_other_hash || ftrace_hash_empty(other_hash)))
1646 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
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((rec->flags & ~FTRACE_FL_MASK) == 0))
1660 /* Shortcut, if we handled all records, we are done. */
1661 if (!all && count == hash->count)
1663 } while_for_each_ftrace_rec();
1666 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1669 __ftrace_hash_rec_update(ops, filter_hash, 0);
1672 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1675 __ftrace_hash_rec_update(ops, filter_hash, 1);
1678 static void print_ip_ins(const char *fmt, unsigned char *p)
1682 printk(KERN_CONT "%s", fmt);
1684 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1685 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1689 * ftrace_bug - report and shutdown function tracer
1690 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1691 * @ip: The address that failed
1693 * The arch code that enables or disables the function tracing
1694 * can call ftrace_bug() when it has detected a problem in
1695 * modifying the code. @failed should be one of either:
1696 * EFAULT - if the problem happens on reading the @ip address
1697 * EINVAL - if what is read at @ip is not what was expected
1698 * EPERM - if the problem happens on writting to the @ip address
1700 void ftrace_bug(int failed, unsigned long ip)
1704 FTRACE_WARN_ON_ONCE(1);
1705 pr_info("ftrace faulted on modifying ");
1709 FTRACE_WARN_ON_ONCE(1);
1710 pr_info("ftrace failed to modify ");
1712 print_ip_ins(" actual: ", (unsigned char *)ip);
1713 printk(KERN_CONT "\n");
1716 FTRACE_WARN_ON_ONCE(1);
1717 pr_info("ftrace faulted on writing ");
1721 FTRACE_WARN_ON_ONCE(1);
1722 pr_info("ftrace faulted on unknown error ");
1727 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1729 unsigned long flag = 0UL;
1732 * If we are updating calls:
1734 * If the record has a ref count, then we need to enable it
1735 * because someone is using it.
1737 * Otherwise we make sure its disabled.
1739 * If we are disabling calls, then disable all records that
1742 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1743 flag = FTRACE_FL_ENABLED;
1746 * If enabling and the REGS flag does not match the REGS_EN, then
1747 * do not ignore this record. Set flags to fail the compare against
1751 (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1752 flag |= FTRACE_FL_REGS;
1754 /* If the state of this record hasn't changed, then do nothing */
1755 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1756 return FTRACE_UPDATE_IGNORE;
1759 /* Save off if rec is being enabled (for return value) */
1760 flag ^= rec->flags & FTRACE_FL_ENABLED;
1763 rec->flags |= FTRACE_FL_ENABLED;
1764 if (flag & FTRACE_FL_REGS) {
1765 if (rec->flags & FTRACE_FL_REGS)
1766 rec->flags |= FTRACE_FL_REGS_EN;
1768 rec->flags &= ~FTRACE_FL_REGS_EN;
1773 * If this record is being updated from a nop, then
1774 * return UPDATE_MAKE_CALL.
1775 * Otherwise, if the EN flag is set, then return
1776 * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1777 * from the non-save regs, to a save regs function.
1779 * return UPDATE_MODIFY_CALL to tell the caller to convert
1780 * from the save regs, to a non-save regs function.
1782 if (flag & FTRACE_FL_ENABLED)
1783 return FTRACE_UPDATE_MAKE_CALL;
1784 else if (rec->flags & FTRACE_FL_REGS_EN)
1785 return FTRACE_UPDATE_MODIFY_CALL_REGS;
1787 return FTRACE_UPDATE_MODIFY_CALL;
1791 /* If there's no more users, clear all flags */
1792 if (!(rec->flags & ~FTRACE_FL_MASK))
1795 /* Just disable the record (keep REGS state) */
1796 rec->flags &= ~FTRACE_FL_ENABLED;
1799 return FTRACE_UPDATE_MAKE_NOP;
1803 * ftrace_update_record, set a record that now is tracing or not
1804 * @rec: the record to update
1805 * @enable: set to 1 if the record is tracing, zero to force disable
1807 * The records that represent all functions that can be traced need
1808 * to be updated when tracing has been enabled.
1810 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1812 return ftrace_check_record(rec, enable, 1);
1816 * ftrace_test_record, check if the record has been enabled or not
1817 * @rec: the record to test
1818 * @enable: set to 1 to check if enabled, 0 if it is disabled
1820 * The arch code may need to test if a record is already set to
1821 * tracing to determine how to modify the function code that it
1824 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1826 return ftrace_check_record(rec, enable, 0);
1830 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1832 unsigned long ftrace_old_addr;
1833 unsigned long ftrace_addr;
1836 ret = ftrace_update_record(rec, enable);
1838 if (rec->flags & FTRACE_FL_REGS)
1839 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1841 ftrace_addr = (unsigned long)FTRACE_ADDR;
1844 case FTRACE_UPDATE_IGNORE:
1847 case FTRACE_UPDATE_MAKE_CALL:
1848 return ftrace_make_call(rec, ftrace_addr);
1850 case FTRACE_UPDATE_MAKE_NOP:
1851 return ftrace_make_nop(NULL, rec, ftrace_addr);
1853 case FTRACE_UPDATE_MODIFY_CALL_REGS:
1854 case FTRACE_UPDATE_MODIFY_CALL:
1855 if (rec->flags & FTRACE_FL_REGS)
1856 ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1858 ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1860 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1863 return -1; /* unknow ftrace bug */
1866 void __weak ftrace_replace_code(int enable)
1868 struct dyn_ftrace *rec;
1869 struct ftrace_page *pg;
1872 if (unlikely(ftrace_disabled))
1875 do_for_each_ftrace_rec(pg, rec) {
1876 failed = __ftrace_replace_code(rec, enable);
1878 ftrace_bug(failed, rec->ip);
1879 /* Stop processing */
1882 } while_for_each_ftrace_rec();
1885 struct ftrace_rec_iter {
1886 struct ftrace_page *pg;
1891 * ftrace_rec_iter_start, start up iterating over traced functions
1893 * Returns an iterator handle that is used to iterate over all
1894 * the records that represent address locations where functions
1897 * May return NULL if no records are available.
1899 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1902 * We only use a single iterator.
1903 * Protected by the ftrace_lock mutex.
1905 static struct ftrace_rec_iter ftrace_rec_iter;
1906 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1908 iter->pg = ftrace_pages_start;
1911 /* Could have empty pages */
1912 while (iter->pg && !iter->pg->index)
1913 iter->pg = iter->pg->next;
1922 * ftrace_rec_iter_next, get the next record to process.
1923 * @iter: The handle to the iterator.
1925 * Returns the next iterator after the given iterator @iter.
1927 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1931 if (iter->index >= iter->pg->index) {
1932 iter->pg = iter->pg->next;
1935 /* Could have empty pages */
1936 while (iter->pg && !iter->pg->index)
1937 iter->pg = iter->pg->next;
1947 * ftrace_rec_iter_record, get the record at the iterator location
1948 * @iter: The current iterator location
1950 * Returns the record that the current @iter is at.
1952 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1954 return &iter->pg->records[iter->index];
1958 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1965 if (unlikely(ftrace_disabled))
1968 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1970 ftrace_bug(ret, ip);
1977 * archs can override this function if they must do something
1978 * before the modifying code is performed.
1980 int __weak ftrace_arch_code_modify_prepare(void)
1986 * archs can override this function if they must do something
1987 * after the modifying code is performed.
1989 int __weak ftrace_arch_code_modify_post_process(void)
1994 void ftrace_modify_all_code(int command)
1996 int update = command & FTRACE_UPDATE_TRACE_FUNC;
1999 * If the ftrace_caller calls a ftrace_ops func directly,
2000 * we need to make sure that it only traces functions it
2001 * expects to trace. When doing the switch of functions,
2002 * we need to update to the ftrace_ops_list_func first
2003 * before the transition between old and new calls are set,
2004 * as the ftrace_ops_list_func will check the ops hashes
2005 * to make sure the ops are having the right functions
2009 ftrace_update_ftrace_func(ftrace_ops_list_func);
2011 if (command & FTRACE_UPDATE_CALLS)
2012 ftrace_replace_code(1);
2013 else if (command & FTRACE_DISABLE_CALLS)
2014 ftrace_replace_code(0);
2016 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2017 function_trace_op = set_function_trace_op;
2019 /* If irqs are disabled, we are in stop machine */
2020 if (!irqs_disabled())
2021 smp_call_function(ftrace_sync_ipi, NULL, 1);
2022 ftrace_update_ftrace_func(ftrace_trace_function);
2025 if (command & FTRACE_START_FUNC_RET)
2026 ftrace_enable_ftrace_graph_caller();
2027 else if (command & FTRACE_STOP_FUNC_RET)
2028 ftrace_disable_ftrace_graph_caller();
2031 static int __ftrace_modify_code(void *data)
2033 int *command = data;
2035 ftrace_modify_all_code(*command);
2041 * ftrace_run_stop_machine, go back to the stop machine method
2042 * @command: The command to tell ftrace what to do
2044 * If an arch needs to fall back to the stop machine method, the
2045 * it can call this function.
2047 void ftrace_run_stop_machine(int command)
2049 stop_machine(__ftrace_modify_code, &command, NULL);
2053 * arch_ftrace_update_code, modify the code to trace or not trace
2054 * @command: The command that needs to be done
2056 * Archs can override this function if it does not need to
2057 * run stop_machine() to modify code.
2059 void __weak arch_ftrace_update_code(int command)
2061 ftrace_run_stop_machine(command);
2064 static void ftrace_run_update_code(int command)
2068 ret = ftrace_arch_code_modify_prepare();
2069 FTRACE_WARN_ON(ret);
2073 * Do not call function tracer while we update the code.
2074 * We are in stop machine.
2076 function_trace_stop++;
2079 * By default we use stop_machine() to modify the code.
2080 * But archs can do what ever they want as long as it
2081 * is safe. The stop_machine() is the safest, but also
2082 * produces the most overhead.
2084 arch_ftrace_update_code(command);
2086 function_trace_stop--;
2088 ret = ftrace_arch_code_modify_post_process();
2089 FTRACE_WARN_ON(ret);
2092 static ftrace_func_t saved_ftrace_func;
2093 static int ftrace_start_up;
2094 static int global_start_up;
2096 static void ftrace_startup_enable(int command)
2098 if (saved_ftrace_func != ftrace_trace_function) {
2099 saved_ftrace_func = ftrace_trace_function;
2100 command |= FTRACE_UPDATE_TRACE_FUNC;
2103 if (!command || !ftrace_enabled)
2106 ftrace_run_update_code(command);
2109 static int ftrace_startup(struct ftrace_ops *ops, int command)
2111 bool hash_enable = true;
2114 if (unlikely(ftrace_disabled))
2117 ret = __register_ftrace_function(ops);
2122 command |= FTRACE_UPDATE_CALLS;
2124 /* ops marked global share the filter hashes */
2125 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2127 /* Don't update hash if global is already set */
2128 if (global_start_up)
2129 hash_enable = false;
2133 ops->flags |= FTRACE_OPS_FL_ENABLED;
2135 ftrace_hash_rec_enable(ops, 1);
2137 ftrace_startup_enable(command);
2142 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2144 bool hash_disable = true;
2147 if (unlikely(ftrace_disabled))
2150 ret = __unregister_ftrace_function(ops);
2156 * Just warn in case of unbalance, no need to kill ftrace, it's not
2157 * critical but the ftrace_call callers may be never nopped again after
2158 * further ftrace uses.
2160 WARN_ON_ONCE(ftrace_start_up < 0);
2162 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2165 WARN_ON_ONCE(global_start_up < 0);
2166 /* Don't update hash if global still has users */
2167 if (global_start_up) {
2168 WARN_ON_ONCE(!ftrace_start_up);
2169 hash_disable = false;
2174 ftrace_hash_rec_disable(ops, 1);
2176 if (ops != &global_ops || !global_start_up)
2177 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2179 command |= FTRACE_UPDATE_CALLS;
2181 if (saved_ftrace_func != ftrace_trace_function) {
2182 saved_ftrace_func = ftrace_trace_function;
2183 command |= FTRACE_UPDATE_TRACE_FUNC;
2186 if (!command || !ftrace_enabled) {
2188 * If these are control ops, they still need their
2189 * per_cpu field freed. Since, function tracing is
2190 * not currently active, we can just free them
2191 * without synchronizing all CPUs.
2193 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2194 control_ops_free(ops);
2198 ftrace_run_update_code(command);
2201 * Dynamic ops may be freed, we must make sure that all
2202 * callers are done before leaving this function.
2203 * The same goes for freeing the per_cpu data of the control
2206 * Again, normal synchronize_sched() is not good enough.
2207 * We need to do a hard force of sched synchronization.
2208 * This is because we use preempt_disable() to do RCU, but
2209 * the function tracers can be called where RCU is not watching
2210 * (like before user_exit()). We can not rely on the RCU
2211 * infrastructure to do the synchronization, thus we must do it
2214 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2215 schedule_on_each_cpu(ftrace_sync);
2217 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2218 control_ops_free(ops);
2224 static void ftrace_startup_sysctl(void)
2226 if (unlikely(ftrace_disabled))
2229 /* Force update next time */
2230 saved_ftrace_func = NULL;
2231 /* ftrace_start_up is true if we want ftrace running */
2232 if (ftrace_start_up)
2233 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2236 static void ftrace_shutdown_sysctl(void)
2238 if (unlikely(ftrace_disabled))
2241 /* ftrace_start_up is true if ftrace is running */
2242 if (ftrace_start_up)
2243 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2246 static cycle_t ftrace_update_time;
2247 unsigned long ftrace_update_tot_cnt;
2249 static inline int ops_traces_mod(struct ftrace_ops *ops)
2252 * Filter_hash being empty will default to trace module.
2253 * But notrace hash requires a test of individual module functions.
2255 return ftrace_hash_empty(ops->filter_hash) &&
2256 ftrace_hash_empty(ops->notrace_hash);
2260 * Check if the current ops references the record.
2262 * If the ops traces all functions, then it was already accounted for.
2263 * If the ops does not trace the current record function, skip it.
2264 * If the ops ignores the function via notrace filter, skip it.
2267 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2269 /* If ops isn't enabled, ignore it */
2270 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2273 /* If ops traces all mods, we already accounted for it */
2274 if (ops_traces_mod(ops))
2277 /* The function must be in the filter */
2278 if (!ftrace_hash_empty(ops->filter_hash) &&
2279 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2282 /* If in notrace hash, we ignore it too */
2283 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2289 static int referenced_filters(struct dyn_ftrace *rec)
2291 struct ftrace_ops *ops;
2294 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2295 if (ops_references_rec(ops, rec))
2302 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2304 struct ftrace_page *pg;
2305 struct dyn_ftrace *p;
2306 cycle_t start, stop;
2307 unsigned long update_cnt = 0;
2308 unsigned long ref = 0;
2313 * When adding a module, we need to check if tracers are
2314 * currently enabled and if they are set to trace all functions.
2315 * If they are, we need to enable the module functions as well
2316 * as update the reference counts for those function records.
2319 struct ftrace_ops *ops;
2321 for (ops = ftrace_ops_list;
2322 ops != &ftrace_list_end; ops = ops->next) {
2323 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2324 if (ops_traces_mod(ops))
2332 start = ftrace_now(raw_smp_processor_id());
2334 for (pg = new_pgs; pg; pg = pg->next) {
2336 for (i = 0; i < pg->index; i++) {
2339 /* If something went wrong, bail without enabling anything */
2340 if (unlikely(ftrace_disabled))
2343 p = &pg->records[i];
2345 cnt += referenced_filters(p);
2349 * Do the initial record conversion from mcount jump
2350 * to the NOP instructions.
2352 if (!ftrace_code_disable(mod, p))
2358 * If the tracing is enabled, go ahead and enable the record.
2360 * The reason not to enable the record immediatelly is the
2361 * inherent check of ftrace_make_nop/ftrace_make_call for
2362 * correct previous instructions. Making first the NOP
2363 * conversion puts the module to the correct state, thus
2364 * passing the ftrace_make_call check.
2366 if (ftrace_start_up && cnt) {
2367 int failed = __ftrace_replace_code(p, 1);
2369 ftrace_bug(failed, p->ip);
2374 stop = ftrace_now(raw_smp_processor_id());
2375 ftrace_update_time = stop - start;
2376 ftrace_update_tot_cnt += update_cnt;
2381 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2386 if (WARN_ON(!count))
2389 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2392 * We want to fill as much as possible. No more than a page
2395 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2399 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2402 /* if we can't allocate this size, try something smaller */
2409 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2418 static struct ftrace_page *
2419 ftrace_allocate_pages(unsigned long num_to_init)
2421 struct ftrace_page *start_pg;
2422 struct ftrace_page *pg;
2429 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2434 * Try to allocate as much as possible in one continues
2435 * location that fills in all of the space. We want to
2436 * waste as little space as possible.
2439 cnt = ftrace_allocate_records(pg, num_to_init);
2447 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2458 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2459 free_pages((unsigned long)pg->records, order);
2460 start_pg = pg->next;
2464 pr_info("ftrace: FAILED to allocate memory for functions\n");
2468 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2470 struct ftrace_iterator {
2473 struct ftrace_page *pg;
2474 struct dyn_ftrace *func;
2475 struct ftrace_func_probe *probe;
2476 struct trace_parser parser;
2477 struct ftrace_hash *hash;
2478 struct ftrace_ops *ops;
2485 t_hash_next(struct seq_file *m, loff_t *pos)
2487 struct ftrace_iterator *iter = m->private;
2488 struct hlist_node *hnd = NULL;
2489 struct hlist_head *hhd;
2495 hnd = &iter->probe->node;
2497 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2500 hhd = &ftrace_func_hash[iter->hidx];
2502 if (hlist_empty(hhd)) {
2518 if (WARN_ON_ONCE(!hnd))
2521 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2526 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2528 struct ftrace_iterator *iter = m->private;
2532 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2535 if (iter->func_pos > *pos)
2539 for (l = 0; l <= (*pos - iter->func_pos); ) {
2540 p = t_hash_next(m, &l);
2547 /* Only set this if we have an item */
2548 iter->flags |= FTRACE_ITER_HASH;
2554 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2556 struct ftrace_func_probe *rec;
2559 if (WARN_ON_ONCE(!rec))
2562 if (rec->ops->print)
2563 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2565 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2568 seq_printf(m, ":%p", rec->data);
2575 t_next(struct seq_file *m, void *v, loff_t *pos)
2577 struct ftrace_iterator *iter = m->private;
2578 struct ftrace_ops *ops = iter->ops;
2579 struct dyn_ftrace *rec = NULL;
2581 if (unlikely(ftrace_disabled))
2584 if (iter->flags & FTRACE_ITER_HASH)
2585 return t_hash_next(m, pos);
2588 iter->pos = iter->func_pos = *pos;
2590 if (iter->flags & FTRACE_ITER_PRINTALL)
2591 return t_hash_start(m, pos);
2594 if (iter->idx >= iter->pg->index) {
2595 if (iter->pg->next) {
2596 iter->pg = iter->pg->next;
2601 rec = &iter->pg->records[iter->idx++];
2602 if (((iter->flags & FTRACE_ITER_FILTER) &&
2603 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2605 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2606 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2608 ((iter->flags & FTRACE_ITER_ENABLED) &&
2609 !(rec->flags & FTRACE_FL_ENABLED))) {
2617 return t_hash_start(m, pos);
2624 static void reset_iter_read(struct ftrace_iterator *iter)
2628 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2631 static void *t_start(struct seq_file *m, loff_t *pos)
2633 struct ftrace_iterator *iter = m->private;
2634 struct ftrace_ops *ops = iter->ops;
2638 mutex_lock(&ftrace_lock);
2640 if (unlikely(ftrace_disabled))
2644 * If an lseek was done, then reset and start from beginning.
2646 if (*pos < iter->pos)
2647 reset_iter_read(iter);
2650 * For set_ftrace_filter reading, if we have the filter
2651 * off, we can short cut and just print out that all
2652 * functions are enabled.
2654 if (iter->flags & FTRACE_ITER_FILTER &&
2655 ftrace_hash_empty(ops->filter_hash)) {
2657 return t_hash_start(m, pos);
2658 iter->flags |= FTRACE_ITER_PRINTALL;
2659 /* reset in case of seek/pread */
2660 iter->flags &= ~FTRACE_ITER_HASH;
2664 if (iter->flags & FTRACE_ITER_HASH)
2665 return t_hash_start(m, pos);
2668 * Unfortunately, we need to restart at ftrace_pages_start
2669 * every time we let go of the ftrace_mutex. This is because
2670 * those pointers can change without the lock.
2672 iter->pg = ftrace_pages_start;
2674 for (l = 0; l <= *pos; ) {
2675 p = t_next(m, p, &l);
2681 return t_hash_start(m, pos);
2686 static void t_stop(struct seq_file *m, void *p)
2688 mutex_unlock(&ftrace_lock);
2691 static int t_show(struct seq_file *m, void *v)
2693 struct ftrace_iterator *iter = m->private;
2694 struct dyn_ftrace *rec;
2696 if (iter->flags & FTRACE_ITER_HASH)
2697 return t_hash_show(m, iter);
2699 if (iter->flags & FTRACE_ITER_PRINTALL) {
2700 seq_printf(m, "#### all functions enabled ####\n");
2709 seq_printf(m, "%ps", (void *)rec->ip);
2710 if (iter->flags & FTRACE_ITER_ENABLED)
2711 seq_printf(m, " (%ld)%s",
2712 rec->flags & ~FTRACE_FL_MASK,
2713 rec->flags & FTRACE_FL_REGS ? " R" : "");
2714 seq_printf(m, "\n");
2719 static const struct seq_operations show_ftrace_seq_ops = {
2727 ftrace_avail_open(struct inode *inode, struct file *file)
2729 struct ftrace_iterator *iter;
2731 if (unlikely(ftrace_disabled))
2734 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2736 iter->pg = ftrace_pages_start;
2737 iter->ops = &global_ops;
2740 return iter ? 0 : -ENOMEM;
2744 ftrace_enabled_open(struct inode *inode, struct file *file)
2746 struct ftrace_iterator *iter;
2748 if (unlikely(ftrace_disabled))
2751 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2753 iter->pg = ftrace_pages_start;
2754 iter->flags = FTRACE_ITER_ENABLED;
2755 iter->ops = &global_ops;
2758 return iter ? 0 : -ENOMEM;
2761 static void ftrace_filter_reset(struct ftrace_hash *hash)
2763 mutex_lock(&ftrace_lock);
2764 ftrace_hash_clear(hash);
2765 mutex_unlock(&ftrace_lock);
2769 * ftrace_regex_open - initialize function tracer filter files
2770 * @ops: The ftrace_ops that hold the hash filters
2771 * @flag: The type of filter to process
2772 * @inode: The inode, usually passed in to your open routine
2773 * @file: The file, usually passed in to your open routine
2775 * ftrace_regex_open() initializes the filter files for the
2776 * @ops. Depending on @flag it may process the filter hash or
2777 * the notrace hash of @ops. With this called from the open
2778 * routine, you can use ftrace_filter_write() for the write
2779 * routine if @flag has FTRACE_ITER_FILTER set, or
2780 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2781 * tracing_lseek() should be used as the lseek routine, and
2782 * release must call ftrace_regex_release().
2785 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2786 struct inode *inode, struct file *file)
2788 struct ftrace_iterator *iter;
2789 struct ftrace_hash *hash;
2792 ftrace_ops_init(ops);
2794 if (unlikely(ftrace_disabled))
2797 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2801 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2809 mutex_lock(&ops->regex_lock);
2811 if (flag & FTRACE_ITER_NOTRACE)
2812 hash = ops->notrace_hash;
2814 hash = ops->filter_hash;
2816 if (file->f_mode & FMODE_WRITE) {
2817 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2819 trace_parser_put(&iter->parser);
2826 if ((file->f_mode & FMODE_WRITE) &&
2827 (file->f_flags & O_TRUNC))
2828 ftrace_filter_reset(iter->hash);
2830 if (file->f_mode & FMODE_READ) {
2831 iter->pg = ftrace_pages_start;
2833 ret = seq_open(file, &show_ftrace_seq_ops);
2835 struct seq_file *m = file->private_data;
2839 free_ftrace_hash(iter->hash);
2840 trace_parser_put(&iter->parser);
2844 file->private_data = iter;
2847 mutex_unlock(&ops->regex_lock);
2853 ftrace_filter_open(struct inode *inode, struct file *file)
2855 struct ftrace_ops *ops = inode->i_private;
2857 return ftrace_regex_open(ops,
2858 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2863 ftrace_notrace_open(struct inode *inode, struct file *file)
2865 struct ftrace_ops *ops = inode->i_private;
2867 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
2871 static int ftrace_match(char *str, char *regex, int len, int type)
2878 if (strcmp(str, regex) == 0)
2881 case MATCH_FRONT_ONLY:
2882 if (strncmp(str, regex, len) == 0)
2885 case MATCH_MIDDLE_ONLY:
2886 if (strstr(str, regex))
2889 case MATCH_END_ONLY:
2891 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2900 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2902 struct ftrace_func_entry *entry;
2905 entry = ftrace_lookup_ip(hash, rec->ip);
2907 /* Do nothing if it doesn't exist */
2911 free_hash_entry(hash, entry);
2913 /* Do nothing if it exists */
2917 ret = add_hash_entry(hash, rec->ip);
2923 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2924 char *regex, int len, int type)
2926 char str[KSYM_SYMBOL_LEN];
2929 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2932 /* module lookup requires matching the module */
2933 if (!modname || strcmp(modname, mod))
2936 /* blank search means to match all funcs in the mod */
2941 return ftrace_match(str, regex, len, type);
2945 match_records(struct ftrace_hash *hash, char *buff,
2946 int len, char *mod, int not)
2948 unsigned search_len = 0;
2949 struct ftrace_page *pg;
2950 struct dyn_ftrace *rec;
2951 int type = MATCH_FULL;
2952 char *search = buff;
2957 type = filter_parse_regex(buff, len, &search, ¬);
2958 search_len = strlen(search);
2961 mutex_lock(&ftrace_lock);
2963 if (unlikely(ftrace_disabled))
2966 do_for_each_ftrace_rec(pg, rec) {
2967 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2968 ret = enter_record(hash, rec, not);
2975 } while_for_each_ftrace_rec();
2977 mutex_unlock(&ftrace_lock);
2983 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2985 return match_records(hash, buff, len, NULL, 0);
2989 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2993 /* blank or '*' mean the same */
2994 if (strcmp(buff, "*") == 0)
2997 /* handle the case of 'dont filter this module' */
2998 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
3003 return match_records(hash, buff, strlen(buff), mod, not);
3007 * We register the module command as a template to show others how
3008 * to register the a command as well.
3012 ftrace_mod_callback(struct ftrace_hash *hash,
3013 char *func, char *cmd, char *param, int enable)
3019 * cmd == 'mod' because we only registered this func
3020 * for the 'mod' ftrace_func_command.
3021 * But if you register one func with multiple commands,
3022 * you can tell which command was used by the cmd
3026 /* we must have a module name */
3030 mod = strsep(¶m, ":");
3034 ret = ftrace_match_module_records(hash, func, mod);
3043 static struct ftrace_func_command ftrace_mod_cmd = {
3045 .func = ftrace_mod_callback,
3048 static int __init ftrace_mod_cmd_init(void)
3050 return register_ftrace_command(&ftrace_mod_cmd);
3052 core_initcall(ftrace_mod_cmd_init);
3054 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3055 struct ftrace_ops *op, struct pt_regs *pt_regs)
3057 struct ftrace_func_probe *entry;
3058 struct hlist_head *hhd;
3061 key = hash_long(ip, FTRACE_HASH_BITS);
3063 hhd = &ftrace_func_hash[key];
3065 if (hlist_empty(hhd))
3069 * Disable preemption for these calls to prevent a RCU grace
3070 * period. This syncs the hash iteration and freeing of items
3071 * on the hash. rcu_read_lock is too dangerous here.
3073 preempt_disable_notrace();
3074 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3075 if (entry->ip == ip)
3076 entry->ops->func(ip, parent_ip, &entry->data);
3078 preempt_enable_notrace();
3081 static struct ftrace_ops trace_probe_ops __read_mostly =
3083 .func = function_trace_probe_call,
3084 .flags = FTRACE_OPS_FL_INITIALIZED,
3085 INIT_REGEX_LOCK(trace_probe_ops)
3088 static int ftrace_probe_registered;
3090 static void __enable_ftrace_function_probe(void)
3095 if (ftrace_probe_registered) {
3096 /* still need to update the function call sites */
3098 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3102 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3103 struct hlist_head *hhd = &ftrace_func_hash[i];
3107 /* Nothing registered? */
3108 if (i == FTRACE_FUNC_HASHSIZE)
3111 ret = ftrace_startup(&trace_probe_ops, 0);
3113 ftrace_probe_registered = 1;
3116 static void __disable_ftrace_function_probe(void)
3120 if (!ftrace_probe_registered)
3123 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3124 struct hlist_head *hhd = &ftrace_func_hash[i];
3129 /* no more funcs left */
3130 ftrace_shutdown(&trace_probe_ops, 0);
3132 ftrace_probe_registered = 0;
3136 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3138 if (entry->ops->free)
3139 entry->ops->free(entry->ops, entry->ip, &entry->data);
3144 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3147 struct ftrace_func_probe *entry;
3148 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3149 struct ftrace_hash *hash;
3150 struct ftrace_page *pg;
3151 struct dyn_ftrace *rec;
3158 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3159 len = strlen(search);
3161 /* we do not support '!' for function probes */
3165 mutex_lock(&trace_probe_ops.regex_lock);
3167 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3173 if (unlikely(ftrace_disabled)) {
3178 mutex_lock(&ftrace_lock);
3180 do_for_each_ftrace_rec(pg, rec) {
3182 if (!ftrace_match_record(rec, NULL, search, len, type))
3185 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3187 /* If we did not process any, then return error */
3198 * The caller might want to do something special
3199 * for each function we find. We call the callback
3200 * to give the caller an opportunity to do so.
3203 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3204 /* caller does not like this func */
3210 ret = enter_record(hash, rec, 0);
3218 entry->ip = rec->ip;
3220 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3221 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3223 } while_for_each_ftrace_rec();
3225 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3229 __enable_ftrace_function_probe();
3232 mutex_unlock(&ftrace_lock);
3234 mutex_unlock(&trace_probe_ops.regex_lock);
3235 free_ftrace_hash(hash);
3241 PROBE_TEST_FUNC = 1,
3246 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3247 void *data, int flags)
3249 struct ftrace_func_entry *rec_entry;
3250 struct ftrace_func_probe *entry;
3251 struct ftrace_func_probe *p;
3252 struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3253 struct list_head free_list;
3254 struct ftrace_hash *hash;
3255 struct hlist_node *tmp;
3256 char str[KSYM_SYMBOL_LEN];
3257 int type = MATCH_FULL;
3261 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3266 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3267 len = strlen(search);
3269 /* we do not support '!' for function probes */
3274 mutex_lock(&trace_probe_ops.regex_lock);
3276 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3278 /* Hmm, should report this somehow */
3281 INIT_LIST_HEAD(&free_list);
3283 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3284 struct hlist_head *hhd = &ftrace_func_hash[i];
3286 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3288 /* break up if statements for readability */
3289 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3292 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3295 /* do this last, since it is the most expensive */
3297 kallsyms_lookup(entry->ip, NULL, NULL,
3299 if (!ftrace_match(str, glob, len, type))
3303 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3304 /* It is possible more than one entry had this ip */
3306 free_hash_entry(hash, rec_entry);
3308 hlist_del_rcu(&entry->node);
3309 list_add(&entry->free_list, &free_list);
3312 mutex_lock(&ftrace_lock);
3313 __disable_ftrace_function_probe();
3315 * Remove after the disable is called. Otherwise, if the last
3316 * probe is removed, a null hash means *all enabled*.
3318 ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3319 synchronize_sched();
3320 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3321 list_del(&entry->free_list);
3322 ftrace_free_entry(entry);
3324 mutex_unlock(&ftrace_lock);
3327 mutex_unlock(&trace_probe_ops.regex_lock);
3328 free_ftrace_hash(hash);
3332 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3335 __unregister_ftrace_function_probe(glob, ops, data,
3336 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3340 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3342 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3345 void unregister_ftrace_function_probe_all(char *glob)
3347 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3350 static LIST_HEAD(ftrace_commands);
3351 static DEFINE_MUTEX(ftrace_cmd_mutex);
3354 * Currently we only register ftrace commands from __init, so mark this
3357 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3359 struct ftrace_func_command *p;
3362 mutex_lock(&ftrace_cmd_mutex);
3363 list_for_each_entry(p, &ftrace_commands, list) {
3364 if (strcmp(cmd->name, p->name) == 0) {
3369 list_add(&cmd->list, &ftrace_commands);
3371 mutex_unlock(&ftrace_cmd_mutex);
3377 * Currently we only unregister ftrace commands from __init, so mark
3380 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3382 struct ftrace_func_command *p, *n;
3385 mutex_lock(&ftrace_cmd_mutex);
3386 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3387 if (strcmp(cmd->name, p->name) == 0) {
3389 list_del_init(&p->list);
3394 mutex_unlock(&ftrace_cmd_mutex);
3399 static int ftrace_process_regex(struct ftrace_hash *hash,
3400 char *buff, int len, int enable)
3402 char *func, *command, *next = buff;
3403 struct ftrace_func_command *p;
3406 func = strsep(&next, ":");
3409 ret = ftrace_match_records(hash, func, len);
3419 command = strsep(&next, ":");
3421 mutex_lock(&ftrace_cmd_mutex);
3422 list_for_each_entry(p, &ftrace_commands, list) {
3423 if (strcmp(p->name, command) == 0) {
3424 ret = p->func(hash, func, command, next, enable);
3429 mutex_unlock(&ftrace_cmd_mutex);
3435 ftrace_regex_write(struct file *file, const char __user *ubuf,
3436 size_t cnt, loff_t *ppos, int enable)
3438 struct ftrace_iterator *iter;
3439 struct trace_parser *parser;
3445 if (file->f_mode & FMODE_READ) {
3446 struct seq_file *m = file->private_data;
3449 iter = file->private_data;
3451 if (unlikely(ftrace_disabled))
3454 /* iter->hash is a local copy, so we don't need regex_lock */
3456 parser = &iter->parser;
3457 read = trace_get_user(parser, ubuf, cnt, ppos);
3459 if (read >= 0 && trace_parser_loaded(parser) &&
3460 !trace_parser_cont(parser)) {
3461 ret = ftrace_process_regex(iter->hash, parser->buffer,
3462 parser->idx, enable);
3463 trace_parser_clear(parser);
3474 ftrace_filter_write(struct file *file, const char __user *ubuf,
3475 size_t cnt, loff_t *ppos)
3477 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3481 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3482 size_t cnt, loff_t *ppos)
3484 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3488 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3490 struct ftrace_func_entry *entry;
3492 if (!ftrace_location(ip))
3496 entry = ftrace_lookup_ip(hash, ip);
3499 free_hash_entry(hash, entry);
3503 return add_hash_entry(hash, ip);
3506 static void ftrace_ops_update_code(struct ftrace_ops *ops)
3508 if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
3509 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3513 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3514 unsigned long ip, int remove, int reset, int enable)
3516 struct ftrace_hash **orig_hash;
3517 struct ftrace_hash *hash;
3520 /* All global ops uses the global ops filters */
3521 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3524 if (unlikely(ftrace_disabled))
3527 mutex_lock(&ops->regex_lock);
3530 orig_hash = &ops->filter_hash;
3532 orig_hash = &ops->notrace_hash;
3534 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3537 goto out_regex_unlock;
3541 ftrace_filter_reset(hash);
3542 if (buf && !ftrace_match_records(hash, buf, len)) {
3544 goto out_regex_unlock;
3547 ret = ftrace_match_addr(hash, ip, remove);
3549 goto out_regex_unlock;
3552 mutex_lock(&ftrace_lock);
3553 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3555 ftrace_ops_update_code(ops);
3557 mutex_unlock(&ftrace_lock);
3560 mutex_unlock(&ops->regex_lock);
3562 free_ftrace_hash(hash);
3567 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3568 int reset, int enable)
3570 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3574 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3575 * @ops - the ops to set the filter with
3576 * @ip - the address to add to or remove from the filter.
3577 * @remove - non zero to remove the ip from the filter
3578 * @reset - non zero to reset all filters before applying this filter.
3580 * Filters denote which functions should be enabled when tracing is enabled
3581 * If @ip is NULL, it failes to update filter.
3583 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3584 int remove, int reset)
3586 ftrace_ops_init(ops);
3587 return ftrace_set_addr(ops, ip, remove, reset, 1);
3589 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3592 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3593 int reset, int enable)
3595 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3599 * ftrace_set_filter - set a function to filter on in ftrace
3600 * @ops - the ops to set the filter with
3601 * @buf - the string that holds the function filter text.
3602 * @len - the length of the string.
3603 * @reset - non zero to reset all filters before applying this filter.
3605 * Filters denote which functions should be enabled when tracing is enabled.
3606 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3608 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3611 ftrace_ops_init(ops);
3612 return ftrace_set_regex(ops, buf, len, reset, 1);
3614 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3617 * ftrace_set_notrace - set a function to not trace in ftrace
3618 * @ops - the ops to set the notrace filter with
3619 * @buf - the string that holds the function notrace text.
3620 * @len - the length of the string.
3621 * @reset - non zero to reset all filters before applying this filter.
3623 * Notrace Filters denote which functions should not be enabled when tracing
3624 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3627 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3630 ftrace_ops_init(ops);
3631 return ftrace_set_regex(ops, buf, len, reset, 0);
3633 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3635 * ftrace_set_filter - set a function to filter on in ftrace
3636 * @ops - the ops to set the filter with
3637 * @buf - the string that holds the function filter text.
3638 * @len - the length of the string.
3639 * @reset - non zero to reset all filters before applying this filter.
3641 * Filters denote which functions should be enabled when tracing is enabled.
3642 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3644 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3646 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3648 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3651 * ftrace_set_notrace - set a function to not trace in ftrace
3652 * @ops - the ops to set the notrace filter with
3653 * @buf - the string that holds the function notrace text.
3654 * @len - the length of the string.
3655 * @reset - non zero to reset all filters before applying this filter.
3657 * Notrace Filters denote which functions should not be enabled when tracing
3658 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3661 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3663 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3665 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3668 * command line interface to allow users to set filters on boot up.
3670 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3671 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3672 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3674 /* Used by function selftest to not test if filter is set */
3675 bool ftrace_filter_param __initdata;
3677 static int __init set_ftrace_notrace(char *str)
3679 ftrace_filter_param = true;
3680 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3683 __setup("ftrace_notrace=", set_ftrace_notrace);
3685 static int __init set_ftrace_filter(char *str)
3687 ftrace_filter_param = true;
3688 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3691 __setup("ftrace_filter=", set_ftrace_filter);
3693 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3694 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3695 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
3697 static int __init set_graph_function(char *str)
3699 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3702 __setup("ftrace_graph_filter=", set_graph_function);
3704 static void __init set_ftrace_early_graph(char *buf)
3710 func = strsep(&buf, ",");
3711 /* we allow only one expression at a time */
3712 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3713 FTRACE_GRAPH_MAX_FUNCS, func);
3715 printk(KERN_DEBUG "ftrace: function %s not "
3716 "traceable\n", func);
3719 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3722 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3726 ftrace_ops_init(ops);
3729 func = strsep(&buf, ",");
3730 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3734 static void __init set_ftrace_early_filters(void)
3736 if (ftrace_filter_buf[0])
3737 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3738 if (ftrace_notrace_buf[0])
3739 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3740 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3741 if (ftrace_graph_buf[0])
3742 set_ftrace_early_graph(ftrace_graph_buf);
3743 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3746 int ftrace_regex_release(struct inode *inode, struct file *file)
3748 struct seq_file *m = (struct seq_file *)file->private_data;
3749 struct ftrace_iterator *iter;
3750 struct ftrace_hash **orig_hash;
3751 struct trace_parser *parser;
3755 if (file->f_mode & FMODE_READ) {
3757 seq_release(inode, file);
3759 iter = file->private_data;
3761 parser = &iter->parser;
3762 if (trace_parser_loaded(parser)) {
3763 parser->buffer[parser->idx] = 0;
3764 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3767 trace_parser_put(parser);
3769 mutex_lock(&iter->ops->regex_lock);
3771 if (file->f_mode & FMODE_WRITE) {
3772 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3775 orig_hash = &iter->ops->filter_hash;
3777 orig_hash = &iter->ops->notrace_hash;
3779 mutex_lock(&ftrace_lock);
3780 ret = ftrace_hash_move(iter->ops, filter_hash,
3781 orig_hash, iter->hash);
3783 ftrace_ops_update_code(iter->ops);
3785 mutex_unlock(&ftrace_lock);
3788 mutex_unlock(&iter->ops->regex_lock);
3789 free_ftrace_hash(iter->hash);
3795 static const struct file_operations ftrace_avail_fops = {
3796 .open = ftrace_avail_open,
3798 .llseek = seq_lseek,
3799 .release = seq_release_private,
3802 static const struct file_operations ftrace_enabled_fops = {
3803 .open = ftrace_enabled_open,
3805 .llseek = seq_lseek,
3806 .release = seq_release_private,
3809 static const struct file_operations ftrace_filter_fops = {
3810 .open = ftrace_filter_open,
3812 .write = ftrace_filter_write,
3813 .llseek = tracing_lseek,
3814 .release = ftrace_regex_release,
3817 static const struct file_operations ftrace_notrace_fops = {
3818 .open = ftrace_notrace_open,
3820 .write = ftrace_notrace_write,
3821 .llseek = tracing_lseek,
3822 .release = ftrace_regex_release,
3825 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3827 static DEFINE_MUTEX(graph_lock);
3829 int ftrace_graph_count;
3830 int ftrace_graph_notrace_count;
3831 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3832 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3834 struct ftrace_graph_data {
3835 unsigned long *table;
3838 const struct seq_operations *seq_ops;
3842 __g_next(struct seq_file *m, loff_t *pos)
3844 struct ftrace_graph_data *fgd = m->private;
3846 if (*pos >= *fgd->count)
3848 return &fgd->table[*pos];
3852 g_next(struct seq_file *m, void *v, loff_t *pos)
3855 return __g_next(m, pos);
3858 static void *g_start(struct seq_file *m, loff_t *pos)
3860 struct ftrace_graph_data *fgd = m->private;
3862 mutex_lock(&graph_lock);
3864 /* Nothing, tell g_show to print all functions are enabled */
3865 if (!*fgd->count && !*pos)
3868 return __g_next(m, pos);
3871 static void g_stop(struct seq_file *m, void *p)
3873 mutex_unlock(&graph_lock);
3876 static int g_show(struct seq_file *m, void *v)
3878 unsigned long *ptr = v;
3883 if (ptr == (unsigned long *)1) {
3884 seq_printf(m, "#### all functions enabled ####\n");
3888 seq_printf(m, "%ps\n", (void *)*ptr);
3893 static const struct seq_operations ftrace_graph_seq_ops = {
3901 __ftrace_graph_open(struct inode *inode, struct file *file,
3902 struct ftrace_graph_data *fgd)
3906 mutex_lock(&graph_lock);
3907 if ((file->f_mode & FMODE_WRITE) &&
3908 (file->f_flags & O_TRUNC)) {
3910 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
3912 mutex_unlock(&graph_lock);
3914 if (file->f_mode & FMODE_READ) {
3915 ret = seq_open(file, fgd->seq_ops);
3917 struct seq_file *m = file->private_data;
3921 file->private_data = fgd;
3927 ftrace_graph_open(struct inode *inode, struct file *file)
3929 struct ftrace_graph_data *fgd;
3931 if (unlikely(ftrace_disabled))
3934 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3938 fgd->table = ftrace_graph_funcs;
3939 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3940 fgd->count = &ftrace_graph_count;
3941 fgd->seq_ops = &ftrace_graph_seq_ops;
3943 return __ftrace_graph_open(inode, file, fgd);
3947 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
3949 struct ftrace_graph_data *fgd;
3951 if (unlikely(ftrace_disabled))
3954 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
3958 fgd->table = ftrace_graph_notrace_funcs;
3959 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
3960 fgd->count = &ftrace_graph_notrace_count;
3961 fgd->seq_ops = &ftrace_graph_seq_ops;
3963 return __ftrace_graph_open(inode, file, fgd);
3967 ftrace_graph_release(struct inode *inode, struct file *file)
3969 if (file->f_mode & FMODE_READ) {
3970 struct seq_file *m = file->private_data;
3973 seq_release(inode, file);
3975 kfree(file->private_data);
3982 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
3984 struct dyn_ftrace *rec;
3985 struct ftrace_page *pg;
3994 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3995 if (!not && *idx >= size)
3998 search_len = strlen(search);
4000 mutex_lock(&ftrace_lock);
4002 if (unlikely(ftrace_disabled)) {
4003 mutex_unlock(&ftrace_lock);
4007 do_for_each_ftrace_rec(pg, rec) {
4009 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
4010 /* if it is in the array */
4012 for (i = 0; i < *idx; i++) {
4013 if (array[i] == rec->ip) {
4022 array[(*idx)++] = rec->ip;
4028 array[i] = array[--(*idx)];
4034 } while_for_each_ftrace_rec();
4036 mutex_unlock(&ftrace_lock);
4045 ftrace_graph_write(struct file *file, const char __user *ubuf,
4046 size_t cnt, loff_t *ppos)
4048 struct trace_parser parser;
4049 ssize_t read, ret = 0;
4050 struct ftrace_graph_data *fgd = file->private_data;
4055 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4058 read = trace_get_user(&parser, ubuf, cnt, ppos);
4060 if (read >= 0 && trace_parser_loaded((&parser))) {
4061 parser.buffer[parser.idx] = 0;
4063 mutex_lock(&graph_lock);
4065 /* we allow only one expression at a time */
4066 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4069 mutex_unlock(&graph_lock);
4075 trace_parser_put(&parser);
4080 static const struct file_operations ftrace_graph_fops = {
4081 .open = ftrace_graph_open,
4083 .write = ftrace_graph_write,
4084 .llseek = tracing_lseek,
4085 .release = ftrace_graph_release,
4088 static const struct file_operations ftrace_graph_notrace_fops = {
4089 .open = ftrace_graph_notrace_open,
4091 .write = ftrace_graph_write,
4092 .llseek = tracing_lseek,
4093 .release = ftrace_graph_release,
4095 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4097 void ftrace_create_filter_files(struct ftrace_ops *ops,
4098 struct dentry *parent)
4101 trace_create_file("set_ftrace_filter", 0644, parent,
4102 ops, &ftrace_filter_fops);
4104 trace_create_file("set_ftrace_notrace", 0644, parent,
4105 ops, &ftrace_notrace_fops);
4109 * The name "destroy_filter_files" is really a misnomer. Although
4110 * in the future, it may actualy delete the files, but this is
4111 * really intended to make sure the ops passed in are disabled
4112 * and that when this function returns, the caller is free to
4115 * The "destroy" name is only to match the "create" name that this
4116 * should be paired with.
4118 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4120 mutex_lock(&ftrace_lock);
4121 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4122 ftrace_shutdown(ops, 0);
4123 ops->flags |= FTRACE_OPS_FL_DELETED;
4124 mutex_unlock(&ftrace_lock);
4127 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
4130 trace_create_file("available_filter_functions", 0444,
4131 d_tracer, NULL, &ftrace_avail_fops);
4133 trace_create_file("enabled_functions", 0444,
4134 d_tracer, NULL, &ftrace_enabled_fops);
4136 ftrace_create_filter_files(&global_ops, d_tracer);
4138 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4139 trace_create_file("set_graph_function", 0444, d_tracer,
4141 &ftrace_graph_fops);
4142 trace_create_file("set_graph_notrace", 0444, d_tracer,
4144 &ftrace_graph_notrace_fops);
4145 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4150 static int ftrace_cmp_ips(const void *a, const void *b)
4152 const unsigned long *ipa = a;
4153 const unsigned long *ipb = b;
4162 static void ftrace_swap_ips(void *a, void *b, int size)
4164 unsigned long *ipa = a;
4165 unsigned long *ipb = b;
4173 static int ftrace_process_locs(struct module *mod,
4174 unsigned long *start,
4177 struct ftrace_page *start_pg;
4178 struct ftrace_page *pg;
4179 struct dyn_ftrace *rec;
4180 unsigned long count;
4183 unsigned long flags = 0; /* Shut up gcc */
4186 count = end - start;
4191 sort(start, count, sizeof(*start),
4192 ftrace_cmp_ips, ftrace_swap_ips);
4194 start_pg = ftrace_allocate_pages(count);
4198 mutex_lock(&ftrace_lock);
4201 * Core and each module needs their own pages, as
4202 * modules will free them when they are removed.
4203 * Force a new page to be allocated for modules.
4206 WARN_ON(ftrace_pages || ftrace_pages_start);
4207 /* First initialization */
4208 ftrace_pages = ftrace_pages_start = start_pg;
4213 if (WARN_ON(ftrace_pages->next)) {
4214 /* Hmm, we have free pages? */
4215 while (ftrace_pages->next)
4216 ftrace_pages = ftrace_pages->next;
4219 ftrace_pages->next = start_pg;
4225 addr = ftrace_call_adjust(*p++);
4227 * Some architecture linkers will pad between
4228 * the different mcount_loc sections of different
4229 * object files to satisfy alignments.
4230 * Skip any NULL pointers.
4235 if (pg->index == pg->size) {
4236 /* We should have allocated enough */
4237 if (WARN_ON(!pg->next))
4242 rec = &pg->records[pg->index++];
4246 /* We should have used all pages */
4249 /* Assign the last page to ftrace_pages */
4253 * We only need to disable interrupts on start up
4254 * because we are modifying code that an interrupt
4255 * may execute, and the modification is not atomic.
4256 * But for modules, nothing runs the code we modify
4257 * until we are finished with it, and there's no
4258 * reason to cause large interrupt latencies while we do it.
4261 local_irq_save(flags);
4262 ftrace_update_code(mod, start_pg);
4264 local_irq_restore(flags);
4267 mutex_unlock(&ftrace_lock);
4272 #ifdef CONFIG_MODULES
4274 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4276 void ftrace_release_mod(struct module *mod)
4278 struct dyn_ftrace *rec;
4279 struct ftrace_page **last_pg;
4280 struct ftrace_page *pg;
4283 mutex_lock(&ftrace_lock);
4285 if (ftrace_disabled)
4289 * Each module has its own ftrace_pages, remove
4290 * them from the list.
4292 last_pg = &ftrace_pages_start;
4293 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4294 rec = &pg->records[0];
4295 if (within_module_core(rec->ip, mod)) {
4297 * As core pages are first, the first
4298 * page should never be a module page.
4300 if (WARN_ON(pg == ftrace_pages_start))
4303 /* Check if we are deleting the last page */
4304 if (pg == ftrace_pages)
4305 ftrace_pages = next_to_ftrace_page(last_pg);
4307 *last_pg = pg->next;
4308 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4309 free_pages((unsigned long)pg->records, order);
4312 last_pg = &pg->next;
4315 mutex_unlock(&ftrace_lock);
4318 static void ftrace_init_module(struct module *mod,
4319 unsigned long *start, unsigned long *end)
4321 if (ftrace_disabled || start == end)
4323 ftrace_process_locs(mod, start, end);
4326 static int ftrace_module_notify_enter(struct notifier_block *self,
4327 unsigned long val, void *data)
4329 struct module *mod = data;
4331 if (val == MODULE_STATE_COMING)
4332 ftrace_init_module(mod, mod->ftrace_callsites,
4333 mod->ftrace_callsites +
4334 mod->num_ftrace_callsites);
4338 static int ftrace_module_notify_exit(struct notifier_block *self,
4339 unsigned long val, void *data)
4341 struct module *mod = data;
4343 if (val == MODULE_STATE_GOING)
4344 ftrace_release_mod(mod);
4349 static int ftrace_module_notify_enter(struct notifier_block *self,
4350 unsigned long val, void *data)
4354 static int ftrace_module_notify_exit(struct notifier_block *self,
4355 unsigned long val, void *data)
4359 #endif /* CONFIG_MODULES */
4361 struct notifier_block ftrace_module_enter_nb = {
4362 .notifier_call = ftrace_module_notify_enter,
4363 .priority = INT_MAX, /* Run before anything that can use kprobes */
4366 struct notifier_block ftrace_module_exit_nb = {
4367 .notifier_call = ftrace_module_notify_exit,
4368 .priority = INT_MIN, /* Run after anything that can remove kprobes */
4371 void __init ftrace_init(void)
4373 extern unsigned long __start_mcount_loc[];
4374 extern unsigned long __stop_mcount_loc[];
4375 unsigned long count, addr, flags;
4378 /* Keep the ftrace pointer to the stub */
4379 addr = (unsigned long)ftrace_stub;
4381 local_irq_save(flags);
4382 ret = ftrace_dyn_arch_init(&addr);
4383 local_irq_restore(flags);
4387 count = __stop_mcount_loc - __start_mcount_loc;
4389 pr_info("ftrace: No functions to be traced?\n");
4393 pr_info("ftrace: allocating %ld entries in %ld pages\n",
4394 count, count / ENTRIES_PER_PAGE + 1);
4396 last_ftrace_enabled = ftrace_enabled = 1;
4398 ret = ftrace_process_locs(NULL,
4402 ret = register_module_notifier(&ftrace_module_enter_nb);
4404 pr_warning("Failed to register trace ftrace module enter notifier\n");
4406 ret = register_module_notifier(&ftrace_module_exit_nb);
4408 pr_warning("Failed to register trace ftrace module exit notifier\n");
4410 set_ftrace_early_filters();
4414 ftrace_disabled = 1;
4419 static struct ftrace_ops global_ops = {
4420 .func = ftrace_stub,
4421 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4422 INIT_REGEX_LOCK(global_ops)
4425 static int __init ftrace_nodyn_init(void)
4430 core_initcall(ftrace_nodyn_init);
4432 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4433 static inline void ftrace_startup_enable(int command) { }
4434 /* Keep as macros so we do not need to define the commands */
4435 # define ftrace_startup(ops, command) \
4437 int ___ret = __register_ftrace_function(ops); \
4439 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4442 # define ftrace_shutdown(ops, command) \
4444 int ___ret = __unregister_ftrace_function(ops); \
4446 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
4450 # define ftrace_startup_sysctl() do { } while (0)
4451 # define ftrace_shutdown_sysctl() do { } while (0)
4454 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4459 #endif /* CONFIG_DYNAMIC_FTRACE */
4462 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4463 struct ftrace_ops *op, struct pt_regs *regs)
4465 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4469 * Some of the ops may be dynamically allocated,
4470 * they must be freed after a synchronize_sched().
4472 preempt_disable_notrace();
4473 trace_recursion_set(TRACE_CONTROL_BIT);
4476 * Control funcs (perf) uses RCU. Only trace if
4477 * RCU is currently active.
4479 if (!rcu_is_watching())
4482 do_for_each_ftrace_op(op, ftrace_control_list) {
4483 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4484 !ftrace_function_local_disabled(op) &&
4485 ftrace_ops_test(op, ip, regs))
4486 op->func(ip, parent_ip, op, regs);
4487 } while_for_each_ftrace_op(op);
4489 trace_recursion_clear(TRACE_CONTROL_BIT);
4490 preempt_enable_notrace();
4493 static struct ftrace_ops control_ops = {
4494 .func = ftrace_ops_control_func,
4495 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4496 INIT_REGEX_LOCK(control_ops)
4500 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4501 struct ftrace_ops *ignored, struct pt_regs *regs)
4503 struct ftrace_ops *op;
4506 if (function_trace_stop)
4509 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4514 * Some of the ops may be dynamically allocated,
4515 * they must be freed after a synchronize_sched().
4517 preempt_disable_notrace();
4518 do_for_each_ftrace_op(op, ftrace_ops_list) {
4519 if (ftrace_ops_test(op, ip, regs))
4520 op->func(ip, parent_ip, op, regs);
4521 } while_for_each_ftrace_op(op);
4522 preempt_enable_notrace();
4523 trace_clear_recursion(bit);
4527 * Some archs only support passing ip and parent_ip. Even though
4528 * the list function ignores the op parameter, we do not want any
4529 * C side effects, where a function is called without the caller
4530 * sending a third parameter.
4531 * Archs are to support both the regs and ftrace_ops at the same time.
4532 * If they support ftrace_ops, it is assumed they support regs.
4533 * If call backs want to use regs, they must either check for regs
4534 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4535 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4536 * An architecture can pass partial regs with ftrace_ops and still
4537 * set the ARCH_SUPPORT_FTARCE_OPS.
4539 #if ARCH_SUPPORTS_FTRACE_OPS
4540 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4541 struct ftrace_ops *op, struct pt_regs *regs)
4543 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4546 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4548 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4552 static void clear_ftrace_swapper(void)
4554 struct task_struct *p;
4558 for_each_online_cpu(cpu) {
4560 clear_tsk_trace_trace(p);
4565 static void set_ftrace_swapper(void)
4567 struct task_struct *p;
4571 for_each_online_cpu(cpu) {
4573 set_tsk_trace_trace(p);
4578 static void clear_ftrace_pid(struct pid *pid)
4580 struct task_struct *p;
4583 do_each_pid_task(pid, PIDTYPE_PID, p) {
4584 clear_tsk_trace_trace(p);
4585 } while_each_pid_task(pid, PIDTYPE_PID, p);
4591 static void set_ftrace_pid(struct pid *pid)
4593 struct task_struct *p;
4596 do_each_pid_task(pid, PIDTYPE_PID, p) {
4597 set_tsk_trace_trace(p);
4598 } while_each_pid_task(pid, PIDTYPE_PID, p);
4602 static void clear_ftrace_pid_task(struct pid *pid)
4604 if (pid == ftrace_swapper_pid)
4605 clear_ftrace_swapper();
4607 clear_ftrace_pid(pid);
4610 static void set_ftrace_pid_task(struct pid *pid)
4612 if (pid == ftrace_swapper_pid)
4613 set_ftrace_swapper();
4615 set_ftrace_pid(pid);
4618 static int ftrace_pid_add(int p)
4621 struct ftrace_pid *fpid;
4624 mutex_lock(&ftrace_lock);
4627 pid = ftrace_swapper_pid;
4629 pid = find_get_pid(p);
4636 list_for_each_entry(fpid, &ftrace_pids, list)
4637 if (fpid->pid == pid)
4642 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4646 list_add(&fpid->list, &ftrace_pids);
4649 set_ftrace_pid_task(pid);
4651 ftrace_update_pid_func();
4652 ftrace_startup_enable(0);
4654 mutex_unlock(&ftrace_lock);
4658 if (pid != ftrace_swapper_pid)
4662 mutex_unlock(&ftrace_lock);
4666 static void ftrace_pid_reset(void)
4668 struct ftrace_pid *fpid, *safe;
4670 mutex_lock(&ftrace_lock);
4671 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4672 struct pid *pid = fpid->pid;
4674 clear_ftrace_pid_task(pid);
4676 list_del(&fpid->list);
4680 ftrace_update_pid_func();
4681 ftrace_startup_enable(0);
4683 mutex_unlock(&ftrace_lock);
4686 static void *fpid_start(struct seq_file *m, loff_t *pos)
4688 mutex_lock(&ftrace_lock);
4690 if (list_empty(&ftrace_pids) && (!*pos))
4693 return seq_list_start(&ftrace_pids, *pos);
4696 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4701 return seq_list_next(v, &ftrace_pids, pos);
4704 static void fpid_stop(struct seq_file *m, void *p)
4706 mutex_unlock(&ftrace_lock);
4709 static int fpid_show(struct seq_file *m, void *v)
4711 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4713 if (v == (void *)1) {
4714 seq_printf(m, "no pid\n");
4718 if (fpid->pid == ftrace_swapper_pid)
4719 seq_printf(m, "swapper tasks\n");
4721 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4726 static const struct seq_operations ftrace_pid_sops = {
4727 .start = fpid_start,
4734 ftrace_pid_open(struct inode *inode, struct file *file)
4738 if ((file->f_mode & FMODE_WRITE) &&
4739 (file->f_flags & O_TRUNC))
4742 if (file->f_mode & FMODE_READ)
4743 ret = seq_open(file, &ftrace_pid_sops);
4749 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4750 size_t cnt, loff_t *ppos)
4756 if (cnt >= sizeof(buf))
4759 if (copy_from_user(&buf, ubuf, cnt))
4765 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4766 * to clean the filter quietly.
4768 tmp = strstrip(buf);
4769 if (strlen(tmp) == 0)
4772 ret = kstrtol(tmp, 10, &val);
4776 ret = ftrace_pid_add(val);
4778 return ret ? ret : cnt;
4782 ftrace_pid_release(struct inode *inode, struct file *file)
4784 if (file->f_mode & FMODE_READ)
4785 seq_release(inode, file);
4790 static const struct file_operations ftrace_pid_fops = {
4791 .open = ftrace_pid_open,
4792 .write = ftrace_pid_write,
4794 .llseek = tracing_lseek,
4795 .release = ftrace_pid_release,
4798 static __init int ftrace_init_debugfs(void)
4800 struct dentry *d_tracer;
4802 d_tracer = tracing_init_dentry();
4806 ftrace_init_dyn_debugfs(d_tracer);
4808 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4809 NULL, &ftrace_pid_fops);
4811 ftrace_profile_debugfs(d_tracer);
4815 fs_initcall(ftrace_init_debugfs);
4818 * ftrace_kill - kill ftrace
4820 * This function should be used by panic code. It stops ftrace
4821 * but in a not so nice way. If you need to simply kill ftrace
4822 * from a non-atomic section, use ftrace_kill.
4824 void ftrace_kill(void)
4826 ftrace_disabled = 1;
4828 clear_ftrace_function();
4832 * Test if ftrace is dead or not.
4834 int ftrace_is_dead(void)
4836 return ftrace_disabled;
4840 * register_ftrace_function - register a function for profiling
4841 * @ops - ops structure that holds the function for profiling.
4843 * Register a function to be called by all functions in the
4846 * Note: @ops->func and all the functions it calls must be labeled
4847 * with "notrace", otherwise it will go into a
4850 int register_ftrace_function(struct ftrace_ops *ops)
4854 ftrace_ops_init(ops);
4856 mutex_lock(&ftrace_lock);
4858 ret = ftrace_startup(ops, 0);
4860 mutex_unlock(&ftrace_lock);
4864 EXPORT_SYMBOL_GPL(register_ftrace_function);
4867 * unregister_ftrace_function - unregister a function for profiling.
4868 * @ops - ops structure that holds the function to unregister
4870 * Unregister a function that was added to be called by ftrace profiling.
4872 int unregister_ftrace_function(struct ftrace_ops *ops)
4876 mutex_lock(&ftrace_lock);
4877 ret = ftrace_shutdown(ops, 0);
4878 mutex_unlock(&ftrace_lock);
4882 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4885 ftrace_enable_sysctl(struct ctl_table *table, int write,
4886 void __user *buffer, size_t *lenp,
4891 mutex_lock(&ftrace_lock);
4893 if (unlikely(ftrace_disabled))
4896 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4898 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4901 last_ftrace_enabled = !!ftrace_enabled;
4903 if (ftrace_enabled) {
4905 ftrace_startup_sysctl();
4907 /* we are starting ftrace again */
4908 if (ftrace_ops_list != &ftrace_list_end)
4909 update_ftrace_function();
4912 /* stopping ftrace calls (just send to ftrace_stub) */
4913 ftrace_trace_function = ftrace_stub;
4915 ftrace_shutdown_sysctl();
4919 mutex_unlock(&ftrace_lock);
4923 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4925 static int ftrace_graph_active;
4926 static struct notifier_block ftrace_suspend_notifier;
4928 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4933 /* The callbacks that hook a function */
4934 trace_func_graph_ret_t ftrace_graph_return =
4935 (trace_func_graph_ret_t)ftrace_stub;
4936 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4937 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
4939 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4940 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4944 unsigned long flags;
4945 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4946 struct task_struct *g, *t;
4948 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4949 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4950 * sizeof(struct ftrace_ret_stack),
4952 if (!ret_stack_list[i]) {
4960 read_lock_irqsave(&tasklist_lock, flags);
4961 do_each_thread(g, t) {
4967 if (t->ret_stack == NULL) {
4968 atomic_set(&t->tracing_graph_pause, 0);
4969 atomic_set(&t->trace_overrun, 0);
4970 t->curr_ret_stack = -1;
4971 /* Make sure the tasks see the -1 first: */
4973 t->ret_stack = ret_stack_list[start++];
4975 } while_each_thread(g, t);
4978 read_unlock_irqrestore(&tasklist_lock, flags);
4980 for (i = start; i < end; i++)
4981 kfree(ret_stack_list[i]);
4986 ftrace_graph_probe_sched_switch(void *ignore,
4987 struct task_struct *prev, struct task_struct *next)
4989 unsigned long long timestamp;
4993 * Does the user want to count the time a function was asleep.
4994 * If so, do not update the time stamps.
4996 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4999 timestamp = trace_clock_local();
5001 prev->ftrace_timestamp = timestamp;
5003 /* only process tasks that we timestamped */
5004 if (!next->ftrace_timestamp)
5008 * Update all the counters in next to make up for the
5009 * time next was sleeping.
5011 timestamp -= next->ftrace_timestamp;
5013 for (index = next->curr_ret_stack; index >= 0; index--)
5014 next->ret_stack[index].calltime += timestamp;
5017 /* Allocate a return stack for each task */
5018 static int start_graph_tracing(void)
5020 struct ftrace_ret_stack **ret_stack_list;
5023 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5024 sizeof(struct ftrace_ret_stack *),
5027 if (!ret_stack_list)
5030 /* The cpu_boot init_task->ret_stack will never be freed */
5031 for_each_online_cpu(cpu) {
5032 if (!idle_task(cpu)->ret_stack)
5033 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5037 ret = alloc_retstack_tasklist(ret_stack_list);
5038 } while (ret == -EAGAIN);
5041 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5043 pr_info("ftrace_graph: Couldn't activate tracepoint"
5044 " probe to kernel_sched_switch\n");
5047 kfree(ret_stack_list);
5052 * Hibernation protection.
5053 * The state of the current task is too much unstable during
5054 * suspend/restore to disk. We want to protect against that.
5057 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5061 case PM_HIBERNATION_PREPARE:
5062 pause_graph_tracing();
5065 case PM_POST_HIBERNATION:
5066 unpause_graph_tracing();
5072 /* Just a place holder for function graph */
5073 static struct ftrace_ops fgraph_ops __read_mostly = {
5074 .func = ftrace_stub,
5075 .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL |
5076 FTRACE_OPS_FL_RECURSION_SAFE,
5079 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5081 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5083 return __ftrace_graph_entry(trace);
5087 * The function graph tracer should only trace the functions defined
5088 * by set_ftrace_filter and set_ftrace_notrace. If another function
5089 * tracer ops is registered, the graph tracer requires testing the
5090 * function against the global ops, and not just trace any function
5091 * that any ftrace_ops registered.
5093 static void update_function_graph_func(void)
5095 if (ftrace_ops_list == &ftrace_list_end ||
5096 (ftrace_ops_list == &global_ops &&
5097 global_ops.next == &ftrace_list_end))
5098 ftrace_graph_entry = __ftrace_graph_entry;
5100 ftrace_graph_entry = ftrace_graph_entry_test;
5103 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5104 trace_func_graph_ent_t entryfunc)
5108 mutex_lock(&ftrace_lock);
5110 /* we currently allow only one tracer registered at a time */
5111 if (ftrace_graph_active) {
5116 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
5117 register_pm_notifier(&ftrace_suspend_notifier);
5119 ftrace_graph_active++;
5120 ret = start_graph_tracing();
5122 ftrace_graph_active--;
5126 ftrace_graph_return = retfunc;
5129 * Update the indirect function to the entryfunc, and the
5130 * function that gets called to the entry_test first. Then
5131 * call the update fgraph entry function to determine if
5132 * the entryfunc should be called directly or not.
5134 __ftrace_graph_entry = entryfunc;
5135 ftrace_graph_entry = ftrace_graph_entry_test;
5136 update_function_graph_func();
5138 ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
5141 mutex_unlock(&ftrace_lock);
5145 void unregister_ftrace_graph(void)
5147 mutex_lock(&ftrace_lock);
5149 if (unlikely(!ftrace_graph_active))
5152 ftrace_graph_active--;
5153 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5154 ftrace_graph_entry = ftrace_graph_entry_stub;
5155 __ftrace_graph_entry = ftrace_graph_entry_stub;
5156 ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
5157 unregister_pm_notifier(&ftrace_suspend_notifier);
5158 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5161 mutex_unlock(&ftrace_lock);
5164 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5167 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5169 atomic_set(&t->tracing_graph_pause, 0);
5170 atomic_set(&t->trace_overrun, 0);
5171 t->ftrace_timestamp = 0;
5172 /* make curr_ret_stack visible before we add the ret_stack */
5174 t->ret_stack = ret_stack;
5178 * Allocate a return stack for the idle task. May be the first
5179 * time through, or it may be done by CPU hotplug online.
5181 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5183 t->curr_ret_stack = -1;
5185 * The idle task has no parent, it either has its own
5186 * stack or no stack at all.
5189 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5191 if (ftrace_graph_active) {
5192 struct ftrace_ret_stack *ret_stack;
5194 ret_stack = per_cpu(idle_ret_stack, cpu);
5196 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5197 * sizeof(struct ftrace_ret_stack),
5201 per_cpu(idle_ret_stack, cpu) = ret_stack;
5203 graph_init_task(t, ret_stack);
5207 /* Allocate a return stack for newly created task */
5208 void ftrace_graph_init_task(struct task_struct *t)
5210 /* Make sure we do not use the parent ret_stack */
5211 t->ret_stack = NULL;
5212 t->curr_ret_stack = -1;
5214 if (ftrace_graph_active) {
5215 struct ftrace_ret_stack *ret_stack;
5217 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5218 * sizeof(struct ftrace_ret_stack),
5222 graph_init_task(t, ret_stack);
5226 void ftrace_graph_exit_task(struct task_struct *t)
5228 struct ftrace_ret_stack *ret_stack = t->ret_stack;
5230 t->ret_stack = NULL;
5231 /* NULL must become visible to IRQs before we free it: */
5237 void ftrace_graph_stop(void)