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/tracefs.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 #ifdef CONFIG_DYNAMIC_FTRACE
66 #define INIT_OPS_HASH(opsname) \
67 .func_hash = &opsname.local_hash, \
68 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
69 #define ASSIGN_OPS_HASH(opsname, val) \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
74 #define ASSIGN_OPS_HASH(opsname, val)
77 static struct ftrace_ops ftrace_list_end __read_mostly = {
79 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
80 INIT_OPS_HASH(ftrace_list_end)
83 /* ftrace_enabled is a method to turn ftrace on or off */
84 int ftrace_enabled __read_mostly;
85 static int last_ftrace_enabled;
87 /* Current function tracing op */
88 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
89 /* What to set function_trace_op to */
90 static struct ftrace_ops *set_function_trace_op;
92 /* List for set_ftrace_pid's pids. */
93 LIST_HEAD(ftrace_pids);
95 struct list_head list;
99 static bool ftrace_pids_enabled(void)
101 return !list_empty(&ftrace_pids);
104 static void ftrace_update_trampoline(struct ftrace_ops *ops);
107 * ftrace_disabled is set when an anomaly is discovered.
108 * ftrace_disabled is much stronger than ftrace_enabled.
110 static int ftrace_disabled __read_mostly;
112 static DEFINE_MUTEX(ftrace_lock);
114 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
115 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
116 static struct ftrace_ops global_ops;
118 #if ARCH_SUPPORTS_FTRACE_OPS
119 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
120 struct ftrace_ops *op, struct pt_regs *regs);
122 /* See comment below, where ftrace_ops_list_func is defined */
123 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
124 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
128 * Traverse the ftrace_global_list, invoking all entries. The reason that we
129 * can use rcu_dereference_raw_notrace() is that elements removed from this list
130 * are simply leaked, so there is no need to interact with a grace-period
131 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
132 * concurrent insertions into the ftrace_global_list.
134 * Silly Alpha and silly pointer-speculation compiler optimizations!
136 #define do_for_each_ftrace_op(op, list) \
137 op = rcu_dereference_raw_notrace(list); \
141 * Optimized for just a single item in the list (as that is the normal case).
143 #define while_for_each_ftrace_op(op) \
144 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
145 unlikely((op) != &ftrace_list_end))
147 static inline void ftrace_ops_init(struct ftrace_ops *ops)
149 #ifdef CONFIG_DYNAMIC_FTRACE
150 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
151 mutex_init(&ops->local_hash.regex_lock);
152 ops->func_hash = &ops->local_hash;
153 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
159 * ftrace_nr_registered_ops - return number of ops registered
161 * Returns the number of ftrace_ops registered and tracing functions
163 int ftrace_nr_registered_ops(void)
165 struct ftrace_ops *ops;
168 mutex_lock(&ftrace_lock);
170 for (ops = ftrace_ops_list;
171 ops != &ftrace_list_end; ops = ops->next)
174 mutex_unlock(&ftrace_lock);
179 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
180 struct ftrace_ops *op, struct pt_regs *regs)
182 if (!test_tsk_trace_trace(current))
185 op->saved_func(ip, parent_ip, op, regs);
189 * clear_ftrace_function - reset the ftrace function
191 * This NULLs the ftrace function and in essence stops
192 * tracing. There may be lag
194 void clear_ftrace_function(void)
196 ftrace_trace_function = ftrace_stub;
199 static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
203 for_each_possible_cpu(cpu)
204 *per_cpu_ptr(ops->disabled, cpu) = 1;
207 static int per_cpu_ops_alloc(struct ftrace_ops *ops)
209 int __percpu *disabled;
211 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
214 disabled = alloc_percpu(int);
218 ops->disabled = disabled;
219 per_cpu_ops_disable_all(ops);
223 static void ftrace_sync(struct work_struct *work)
226 * This function is just a stub to implement a hard force
227 * of synchronize_sched(). This requires synchronizing
228 * tasks even in userspace and idle.
230 * Yes, function tracing is rude.
234 static void ftrace_sync_ipi(void *data)
236 /* Probably not needed, but do it anyway */
240 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
241 static void update_function_graph_func(void);
243 /* Both enabled by default (can be cleared by function_graph tracer flags */
244 static bool fgraph_sleep_time = true;
245 static bool fgraph_graph_time = true;
248 static inline void update_function_graph_func(void) { }
252 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
255 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
256 * then it needs to call the list anyway.
258 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
259 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
260 return ftrace_ops_list_func;
262 return ftrace_ops_get_func(ops);
265 static void update_ftrace_function(void)
270 * Prepare the ftrace_ops that the arch callback will use.
271 * If there's only one ftrace_ops registered, the ftrace_ops_list
272 * will point to the ops we want.
274 set_function_trace_op = ftrace_ops_list;
276 /* If there's no ftrace_ops registered, just call the stub function */
277 if (ftrace_ops_list == &ftrace_list_end) {
281 * If we are at the end of the list and this ops is
282 * recursion safe and not dynamic and the arch supports passing ops,
283 * then have the mcount trampoline call the function directly.
285 } else if (ftrace_ops_list->next == &ftrace_list_end) {
286 func = ftrace_ops_get_list_func(ftrace_ops_list);
289 /* Just use the default ftrace_ops */
290 set_function_trace_op = &ftrace_list_end;
291 func = ftrace_ops_list_func;
294 update_function_graph_func();
296 /* If there's no change, then do nothing more here */
297 if (ftrace_trace_function == func)
301 * If we are using the list function, it doesn't care
302 * about the function_trace_ops.
304 if (func == ftrace_ops_list_func) {
305 ftrace_trace_function = func;
307 * Don't even bother setting function_trace_ops,
308 * it would be racy to do so anyway.
313 #ifndef CONFIG_DYNAMIC_FTRACE
315 * For static tracing, we need to be a bit more careful.
316 * The function change takes affect immediately. Thus,
317 * we need to coorditate the setting of the function_trace_ops
318 * with the setting of the ftrace_trace_function.
320 * Set the function to the list ops, which will call the
321 * function we want, albeit indirectly, but it handles the
322 * ftrace_ops and doesn't depend on function_trace_op.
324 ftrace_trace_function = ftrace_ops_list_func;
326 * Make sure all CPUs see this. Yes this is slow, but static
327 * tracing is slow and nasty to have enabled.
329 schedule_on_each_cpu(ftrace_sync);
330 /* Now all cpus are using the list ops. */
331 function_trace_op = set_function_trace_op;
332 /* Make sure the function_trace_op is visible on all CPUs */
334 /* Nasty way to force a rmb on all cpus */
335 smp_call_function(ftrace_sync_ipi, NULL, 1);
336 /* OK, we are all set to update the ftrace_trace_function now! */
337 #endif /* !CONFIG_DYNAMIC_FTRACE */
339 ftrace_trace_function = func;
342 int using_ftrace_ops_list_func(void)
344 return ftrace_trace_function == ftrace_ops_list_func;
347 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
351 * We are entering ops into the list but another
352 * CPU might be walking that list. We need to make sure
353 * the ops->next pointer is valid before another CPU sees
354 * the ops pointer included into the list.
356 rcu_assign_pointer(*list, ops);
359 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
361 struct ftrace_ops **p;
364 * If we are removing the last function, then simply point
365 * to the ftrace_stub.
367 if (*list == ops && ops->next == &ftrace_list_end) {
368 *list = &ftrace_list_end;
372 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
383 static void ftrace_update_trampoline(struct ftrace_ops *ops);
385 static int __register_ftrace_function(struct ftrace_ops *ops)
387 if (ops->flags & FTRACE_OPS_FL_DELETED)
390 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
393 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
395 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
396 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
397 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
399 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
400 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
403 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
404 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
407 if (!core_kernel_data((unsigned long)ops))
408 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
410 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
411 if (per_cpu_ops_alloc(ops))
415 add_ftrace_ops(&ftrace_ops_list, ops);
417 /* Always save the function, and reset at unregistering */
418 ops->saved_func = ops->func;
420 if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
421 ops->func = ftrace_pid_func;
423 ftrace_update_trampoline(ops);
426 update_ftrace_function();
431 static int __unregister_ftrace_function(struct ftrace_ops *ops)
435 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
438 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
444 update_ftrace_function();
446 ops->func = ops->saved_func;
451 static void ftrace_update_pid_func(void)
453 bool enabled = ftrace_pids_enabled();
454 struct ftrace_ops *op;
456 /* Only do something if we are tracing something */
457 if (ftrace_trace_function == ftrace_stub)
460 do_for_each_ftrace_op(op, ftrace_ops_list) {
461 if (op->flags & FTRACE_OPS_FL_PID) {
462 op->func = enabled ? ftrace_pid_func :
464 ftrace_update_trampoline(op);
466 } while_for_each_ftrace_op(op);
468 update_ftrace_function();
471 #ifdef CONFIG_FUNCTION_PROFILER
472 struct ftrace_profile {
473 struct hlist_node node;
475 unsigned long counter;
476 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
477 unsigned long long time;
478 unsigned long long time_squared;
482 struct ftrace_profile_page {
483 struct ftrace_profile_page *next;
485 struct ftrace_profile records[];
488 struct ftrace_profile_stat {
490 struct hlist_head *hash;
491 struct ftrace_profile_page *pages;
492 struct ftrace_profile_page *start;
493 struct tracer_stat stat;
496 #define PROFILE_RECORDS_SIZE \
497 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
499 #define PROFILES_PER_PAGE \
500 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
502 static int ftrace_profile_enabled __read_mostly;
504 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
505 static DEFINE_MUTEX(ftrace_profile_lock);
507 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
509 #define FTRACE_PROFILE_HASH_BITS 10
510 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
513 function_stat_next(void *v, int idx)
515 struct ftrace_profile *rec = v;
516 struct ftrace_profile_page *pg;
518 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
524 if ((void *)rec >= (void *)&pg->records[pg->index]) {
528 rec = &pg->records[0];
536 static void *function_stat_start(struct tracer_stat *trace)
538 struct ftrace_profile_stat *stat =
539 container_of(trace, struct ftrace_profile_stat, stat);
541 if (!stat || !stat->start)
544 return function_stat_next(&stat->start->records[0], 0);
547 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
548 /* function graph compares on total time */
549 static int function_stat_cmp(void *p1, void *p2)
551 struct ftrace_profile *a = p1;
552 struct ftrace_profile *b = p2;
554 if (a->time < b->time)
556 if (a->time > b->time)
562 /* not function graph compares against hits */
563 static int function_stat_cmp(void *p1, void *p2)
565 struct ftrace_profile *a = p1;
566 struct ftrace_profile *b = p2;
568 if (a->counter < b->counter)
570 if (a->counter > b->counter)
577 static int function_stat_headers(struct seq_file *m)
579 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
580 seq_puts(m, " Function "
583 "--- ---- --- ---\n");
585 seq_puts(m, " Function Hit\n"
591 static int function_stat_show(struct seq_file *m, void *v)
593 struct ftrace_profile *rec = v;
594 char str[KSYM_SYMBOL_LEN];
596 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
597 static struct trace_seq s;
598 unsigned long long avg;
599 unsigned long long stddev;
601 mutex_lock(&ftrace_profile_lock);
603 /* we raced with function_profile_reset() */
604 if (unlikely(rec->counter == 0)) {
609 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
611 do_div(avg, rec->counter);
612 if (tracing_thresh && (avg < tracing_thresh))
616 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
617 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
622 /* Sample standard deviation (s^2) */
623 if (rec->counter <= 1)
627 * Apply Welford's method:
628 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
630 stddev = rec->counter * rec->time_squared -
631 rec->time * rec->time;
634 * Divide only 1000 for ns^2 -> us^2 conversion.
635 * trace_print_graph_duration will divide 1000 again.
637 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
641 trace_print_graph_duration(rec->time, &s);
642 trace_seq_puts(&s, " ");
643 trace_print_graph_duration(avg, &s);
644 trace_seq_puts(&s, " ");
645 trace_print_graph_duration(stddev, &s);
646 trace_print_seq(m, &s);
650 mutex_unlock(&ftrace_profile_lock);
655 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
657 struct ftrace_profile_page *pg;
659 pg = stat->pages = stat->start;
662 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
667 memset(stat->hash, 0,
668 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
671 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
673 struct ftrace_profile_page *pg;
678 /* If we already allocated, do nothing */
682 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
686 #ifdef CONFIG_DYNAMIC_FTRACE
687 functions = ftrace_update_tot_cnt;
690 * We do not know the number of functions that exist because
691 * dynamic tracing is what counts them. With past experience
692 * we have around 20K functions. That should be more than enough.
693 * It is highly unlikely we will execute every function in
699 pg = stat->start = stat->pages;
701 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
703 for (i = 1; i < pages; i++) {
704 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
715 unsigned long tmp = (unsigned long)pg;
727 static int ftrace_profile_init_cpu(int cpu)
729 struct ftrace_profile_stat *stat;
732 stat = &per_cpu(ftrace_profile_stats, cpu);
735 /* If the profile is already created, simply reset it */
736 ftrace_profile_reset(stat);
741 * We are profiling all functions, but usually only a few thousand
742 * functions are hit. We'll make a hash of 1024 items.
744 size = FTRACE_PROFILE_HASH_SIZE;
746 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
751 /* Preallocate the function profiling pages */
752 if (ftrace_profile_pages_init(stat) < 0) {
761 static int ftrace_profile_init(void)
766 for_each_possible_cpu(cpu) {
767 ret = ftrace_profile_init_cpu(cpu);
775 /* interrupts must be disabled */
776 static struct ftrace_profile *
777 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
779 struct ftrace_profile *rec;
780 struct hlist_head *hhd;
783 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
784 hhd = &stat->hash[key];
786 if (hlist_empty(hhd))
789 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
797 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
798 struct ftrace_profile *rec)
802 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
803 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
807 * The memory is already allocated, this simply finds a new record to use.
809 static struct ftrace_profile *
810 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
812 struct ftrace_profile *rec = NULL;
814 /* prevent recursion (from NMIs) */
815 if (atomic_inc_return(&stat->disabled) != 1)
819 * Try to find the function again since an NMI
820 * could have added it
822 rec = ftrace_find_profiled_func(stat, ip);
826 if (stat->pages->index == PROFILES_PER_PAGE) {
827 if (!stat->pages->next)
829 stat->pages = stat->pages->next;
832 rec = &stat->pages->records[stat->pages->index++];
834 ftrace_add_profile(stat, rec);
837 atomic_dec(&stat->disabled);
843 function_profile_call(unsigned long ip, unsigned long parent_ip,
844 struct ftrace_ops *ops, struct pt_regs *regs)
846 struct ftrace_profile_stat *stat;
847 struct ftrace_profile *rec;
850 if (!ftrace_profile_enabled)
853 local_irq_save(flags);
855 stat = this_cpu_ptr(&ftrace_profile_stats);
856 if (!stat->hash || !ftrace_profile_enabled)
859 rec = ftrace_find_profiled_func(stat, ip);
861 rec = ftrace_profile_alloc(stat, ip);
868 local_irq_restore(flags);
871 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
872 static int profile_graph_entry(struct ftrace_graph_ent *trace)
874 function_profile_call(trace->func, 0, NULL, NULL);
878 static void profile_graph_return(struct ftrace_graph_ret *trace)
880 struct ftrace_profile_stat *stat;
881 unsigned long long calltime;
882 struct ftrace_profile *rec;
885 local_irq_save(flags);
886 stat = this_cpu_ptr(&ftrace_profile_stats);
887 if (!stat->hash || !ftrace_profile_enabled)
890 /* If the calltime was zero'd ignore it */
891 if (!trace->calltime)
894 calltime = trace->rettime - trace->calltime;
896 if (!fgraph_graph_time) {
899 index = trace->depth;
901 /* Append this call time to the parent time to subtract */
903 current->ret_stack[index - 1].subtime += calltime;
905 if (current->ret_stack[index].subtime < calltime)
906 calltime -= current->ret_stack[index].subtime;
911 rec = ftrace_find_profiled_func(stat, trace->func);
913 rec->time += calltime;
914 rec->time_squared += calltime * calltime;
918 local_irq_restore(flags);
921 static int register_ftrace_profiler(void)
923 return register_ftrace_graph(&profile_graph_return,
924 &profile_graph_entry);
927 static void unregister_ftrace_profiler(void)
929 unregister_ftrace_graph();
932 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
933 .func = function_profile_call,
934 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
935 INIT_OPS_HASH(ftrace_profile_ops)
938 static int register_ftrace_profiler(void)
940 return register_ftrace_function(&ftrace_profile_ops);
943 static void unregister_ftrace_profiler(void)
945 unregister_ftrace_function(&ftrace_profile_ops);
947 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
950 ftrace_profile_write(struct file *filp, const char __user *ubuf,
951 size_t cnt, loff_t *ppos)
956 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
962 mutex_lock(&ftrace_profile_lock);
963 if (ftrace_profile_enabled ^ val) {
965 ret = ftrace_profile_init();
971 ret = register_ftrace_profiler();
976 ftrace_profile_enabled = 1;
978 ftrace_profile_enabled = 0;
980 * unregister_ftrace_profiler calls stop_machine
981 * so this acts like an synchronize_sched.
983 unregister_ftrace_profiler();
987 mutex_unlock(&ftrace_profile_lock);
995 ftrace_profile_read(struct file *filp, char __user *ubuf,
996 size_t cnt, loff_t *ppos)
998 char buf[64]; /* big enough to hold a number */
1001 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1002 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1005 static const struct file_operations ftrace_profile_fops = {
1006 .open = tracing_open_generic,
1007 .read = ftrace_profile_read,
1008 .write = ftrace_profile_write,
1009 .llseek = default_llseek,
1012 /* used to initialize the real stat files */
1013 static struct tracer_stat function_stats __initdata = {
1014 .name = "functions",
1015 .stat_start = function_stat_start,
1016 .stat_next = function_stat_next,
1017 .stat_cmp = function_stat_cmp,
1018 .stat_headers = function_stat_headers,
1019 .stat_show = function_stat_show
1022 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1024 struct ftrace_profile_stat *stat;
1025 struct dentry *entry;
1030 for_each_possible_cpu(cpu) {
1031 stat = &per_cpu(ftrace_profile_stats, cpu);
1033 /* allocate enough for function name + cpu number */
1034 name = kmalloc(32, GFP_KERNEL);
1037 * The files created are permanent, if something happens
1038 * we still do not free memory.
1041 "Could not allocate stat file for cpu %d\n",
1045 stat->stat = function_stats;
1046 snprintf(name, 32, "function%d", cpu);
1047 stat->stat.name = name;
1048 ret = register_stat_tracer(&stat->stat);
1051 "Could not register function stat for cpu %d\n",
1058 entry = tracefs_create_file("function_profile_enabled", 0644,
1059 d_tracer, NULL, &ftrace_profile_fops);
1061 pr_warning("Could not create tracefs "
1062 "'function_profile_enabled' entry\n");
1065 #else /* CONFIG_FUNCTION_PROFILER */
1066 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1069 #endif /* CONFIG_FUNCTION_PROFILER */
1071 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1073 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1074 static int ftrace_graph_active;
1076 # define ftrace_graph_active 0
1079 #ifdef CONFIG_DYNAMIC_FTRACE
1081 static struct ftrace_ops *removed_ops;
1084 * Set when doing a global update, like enabling all recs or disabling them.
1085 * It is not set when just updating a single ftrace_ops.
1087 static bool update_all_ops;
1089 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1090 # error Dynamic ftrace depends on MCOUNT_RECORD
1093 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1095 struct ftrace_func_probe {
1096 struct hlist_node node;
1097 struct ftrace_probe_ops *ops;
1098 unsigned long flags;
1101 struct list_head free_list;
1104 struct ftrace_func_entry {
1105 struct hlist_node hlist;
1109 struct ftrace_hash {
1110 unsigned long size_bits;
1111 struct hlist_head *buckets;
1112 unsigned long count;
1113 struct rcu_head rcu;
1117 * We make these constant because no one should touch them,
1118 * but they are used as the default "empty hash", to avoid allocating
1119 * it all the time. These are in a read only section such that if
1120 * anyone does try to modify it, it will cause an exception.
1122 static const struct hlist_head empty_buckets[1];
1123 static const struct ftrace_hash empty_hash = {
1124 .buckets = (struct hlist_head *)empty_buckets,
1126 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1128 static struct ftrace_ops global_ops = {
1129 .func = ftrace_stub,
1130 .local_hash.notrace_hash = EMPTY_HASH,
1131 .local_hash.filter_hash = EMPTY_HASH,
1132 INIT_OPS_HASH(global_ops)
1133 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1134 FTRACE_OPS_FL_INITIALIZED |
1139 * This is used by __kernel_text_address() to return true if the
1140 * address is on a dynamically allocated trampoline that would
1141 * not return true for either core_kernel_text() or
1142 * is_module_text_address().
1144 bool is_ftrace_trampoline(unsigned long addr)
1146 struct ftrace_ops *op;
1150 * Some of the ops may be dynamically allocated,
1151 * they are freed after a synchronize_sched().
1153 preempt_disable_notrace();
1155 do_for_each_ftrace_op(op, ftrace_ops_list) {
1157 * This is to check for dynamically allocated trampolines.
1158 * Trampolines that are in kernel text will have
1159 * core_kernel_text() return true.
1161 if (op->trampoline && op->trampoline_size)
1162 if (addr >= op->trampoline &&
1163 addr < op->trampoline + op->trampoline_size) {
1167 } while_for_each_ftrace_op(op);
1170 preempt_enable_notrace();
1175 struct ftrace_page {
1176 struct ftrace_page *next;
1177 struct dyn_ftrace *records;
1182 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1183 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1185 /* estimate from running different kernels */
1186 #define NR_TO_INIT 10000
1188 static struct ftrace_page *ftrace_pages_start;
1189 static struct ftrace_page *ftrace_pages;
1191 static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1193 return !hash || !hash->count;
1196 static struct ftrace_func_entry *
1197 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1200 struct ftrace_func_entry *entry;
1201 struct hlist_head *hhd;
1203 if (ftrace_hash_empty(hash))
1206 if (hash->size_bits > 0)
1207 key = hash_long(ip, hash->size_bits);
1211 hhd = &hash->buckets[key];
1213 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1214 if (entry->ip == ip)
1220 static void __add_hash_entry(struct ftrace_hash *hash,
1221 struct ftrace_func_entry *entry)
1223 struct hlist_head *hhd;
1226 if (hash->size_bits)
1227 key = hash_long(entry->ip, hash->size_bits);
1231 hhd = &hash->buckets[key];
1232 hlist_add_head(&entry->hlist, hhd);
1236 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1238 struct ftrace_func_entry *entry;
1240 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1245 __add_hash_entry(hash, entry);
1251 free_hash_entry(struct ftrace_hash *hash,
1252 struct ftrace_func_entry *entry)
1254 hlist_del(&entry->hlist);
1260 remove_hash_entry(struct ftrace_hash *hash,
1261 struct ftrace_func_entry *entry)
1263 hlist_del(&entry->hlist);
1267 static void ftrace_hash_clear(struct ftrace_hash *hash)
1269 struct hlist_head *hhd;
1270 struct hlist_node *tn;
1271 struct ftrace_func_entry *entry;
1272 int size = 1 << hash->size_bits;
1278 for (i = 0; i < size; i++) {
1279 hhd = &hash->buckets[i];
1280 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1281 free_hash_entry(hash, entry);
1283 FTRACE_WARN_ON(hash->count);
1286 static void free_ftrace_hash(struct ftrace_hash *hash)
1288 if (!hash || hash == EMPTY_HASH)
1290 ftrace_hash_clear(hash);
1291 kfree(hash->buckets);
1295 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1297 struct ftrace_hash *hash;
1299 hash = container_of(rcu, struct ftrace_hash, rcu);
1300 free_ftrace_hash(hash);
1303 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1305 if (!hash || hash == EMPTY_HASH)
1307 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1310 void ftrace_free_filter(struct ftrace_ops *ops)
1312 ftrace_ops_init(ops);
1313 free_ftrace_hash(ops->func_hash->filter_hash);
1314 free_ftrace_hash(ops->func_hash->notrace_hash);
1317 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1319 struct ftrace_hash *hash;
1322 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1326 size = 1 << size_bits;
1327 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1329 if (!hash->buckets) {
1334 hash->size_bits = size_bits;
1339 static struct ftrace_hash *
1340 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1342 struct ftrace_func_entry *entry;
1343 struct ftrace_hash *new_hash;
1348 new_hash = alloc_ftrace_hash(size_bits);
1353 if (ftrace_hash_empty(hash))
1356 size = 1 << hash->size_bits;
1357 for (i = 0; i < size; i++) {
1358 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1359 ret = add_hash_entry(new_hash, entry->ip);
1365 FTRACE_WARN_ON(new_hash->count != hash->count);
1370 free_ftrace_hash(new_hash);
1375 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1377 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1379 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1380 struct ftrace_hash *new_hash);
1383 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1384 struct ftrace_hash **dst, struct ftrace_hash *src)
1386 struct ftrace_func_entry *entry;
1387 struct hlist_node *tn;
1388 struct hlist_head *hhd;
1389 struct ftrace_hash *new_hash;
1390 int size = src->count;
1395 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1396 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1400 * If the new source is empty, just free dst and assign it
1404 new_hash = EMPTY_HASH;
1409 * Make the hash size about 1/2 the # found
1411 for (size /= 2; size; size >>= 1)
1414 /* Don't allocate too much */
1415 if (bits > FTRACE_HASH_MAX_BITS)
1416 bits = FTRACE_HASH_MAX_BITS;
1418 new_hash = alloc_ftrace_hash(bits);
1422 size = 1 << src->size_bits;
1423 for (i = 0; i < size; i++) {
1424 hhd = &src->buckets[i];
1425 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1426 remove_hash_entry(src, entry);
1427 __add_hash_entry(new_hash, entry);
1432 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1434 /* IPMODIFY should be updated only when filter_hash updating */
1435 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1437 free_ftrace_hash(new_hash);
1443 * Remove the current set, update the hash and add
1446 ftrace_hash_rec_disable_modify(ops, enable);
1448 rcu_assign_pointer(*dst, new_hash);
1450 ftrace_hash_rec_enable_modify(ops, enable);
1455 static bool hash_contains_ip(unsigned long ip,
1456 struct ftrace_ops_hash *hash)
1459 * The function record is a match if it exists in the filter
1460 * hash and not in the notrace hash. Note, an emty hash is
1461 * considered a match for the filter hash, but an empty
1462 * notrace hash is considered not in the notrace hash.
1464 return (ftrace_hash_empty(hash->filter_hash) ||
1465 ftrace_lookup_ip(hash->filter_hash, ip)) &&
1466 (ftrace_hash_empty(hash->notrace_hash) ||
1467 !ftrace_lookup_ip(hash->notrace_hash, ip));
1471 * Test the hashes for this ops to see if we want to call
1472 * the ops->func or not.
1474 * It's a match if the ip is in the ops->filter_hash or
1475 * the filter_hash does not exist or is empty,
1477 * the ip is not in the ops->notrace_hash.
1479 * This needs to be called with preemption disabled as
1480 * the hashes are freed with call_rcu_sched().
1483 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1485 struct ftrace_ops_hash hash;
1488 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1490 * There's a small race when adding ops that the ftrace handler
1491 * that wants regs, may be called without them. We can not
1492 * allow that handler to be called if regs is NULL.
1494 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1498 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1499 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1501 if (hash_contains_ip(ip, &hash))
1510 * This is a double for. Do not use 'break' to break out of the loop,
1511 * you must use a goto.
1513 #define do_for_each_ftrace_rec(pg, rec) \
1514 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1516 for (_____i = 0; _____i < pg->index; _____i++) { \
1517 rec = &pg->records[_____i];
1519 #define while_for_each_ftrace_rec() \
1524 static int ftrace_cmp_recs(const void *a, const void *b)
1526 const struct dyn_ftrace *key = a;
1527 const struct dyn_ftrace *rec = b;
1529 if (key->flags < rec->ip)
1531 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1536 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1538 struct ftrace_page *pg;
1539 struct dyn_ftrace *rec;
1540 struct dyn_ftrace key;
1543 key.flags = end; /* overload flags, as it is unsigned long */
1545 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1546 if (end < pg->records[0].ip ||
1547 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1549 rec = bsearch(&key, pg->records, pg->index,
1550 sizeof(struct dyn_ftrace),
1560 * ftrace_location - return true if the ip giving is a traced location
1561 * @ip: the instruction pointer to check
1563 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1564 * That is, the instruction that is either a NOP or call to
1565 * the function tracer. It checks the ftrace internal tables to
1566 * determine if the address belongs or not.
1568 unsigned long ftrace_location(unsigned long ip)
1570 return ftrace_location_range(ip, ip);
1574 * ftrace_text_reserved - return true if range contains an ftrace location
1575 * @start: start of range to search
1576 * @end: end of range to search (inclusive). @end points to the last byte to check.
1578 * Returns 1 if @start and @end contains a ftrace location.
1579 * That is, the instruction that is either a NOP or call to
1580 * the function tracer. It checks the ftrace internal tables to
1581 * determine if the address belongs or not.
1583 int ftrace_text_reserved(const void *start, const void *end)
1587 ret = ftrace_location_range((unsigned long)start,
1588 (unsigned long)end);
1593 /* Test if ops registered to this rec needs regs */
1594 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1596 struct ftrace_ops *ops;
1597 bool keep_regs = false;
1599 for (ops = ftrace_ops_list;
1600 ops != &ftrace_list_end; ops = ops->next) {
1601 /* pass rec in as regs to have non-NULL val */
1602 if (ftrace_ops_test(ops, rec->ip, rec)) {
1603 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1613 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1617 struct ftrace_hash *hash;
1618 struct ftrace_hash *other_hash;
1619 struct ftrace_page *pg;
1620 struct dyn_ftrace *rec;
1621 bool update = false;
1625 /* Only update if the ops has been registered */
1626 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1630 * In the filter_hash case:
1631 * If the count is zero, we update all records.
1632 * Otherwise we just update the items in the hash.
1634 * In the notrace_hash case:
1635 * We enable the update in the hash.
1636 * As disabling notrace means enabling the tracing,
1637 * and enabling notrace means disabling, the inc variable
1641 hash = ops->func_hash->filter_hash;
1642 other_hash = ops->func_hash->notrace_hash;
1643 if (ftrace_hash_empty(hash))
1647 hash = ops->func_hash->notrace_hash;
1648 other_hash = ops->func_hash->filter_hash;
1650 * If the notrace hash has no items,
1651 * then there's nothing to do.
1653 if (ftrace_hash_empty(hash))
1657 do_for_each_ftrace_rec(pg, rec) {
1658 int in_other_hash = 0;
1662 if (rec->flags & FTRACE_FL_DISABLED)
1667 * Only the filter_hash affects all records.
1668 * Update if the record is not in the notrace hash.
1670 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1673 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1674 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1677 * If filter_hash is set, we want to match all functions
1678 * that are in the hash but not in the other hash.
1680 * If filter_hash is not set, then we are decrementing.
1681 * That means we match anything that is in the hash
1682 * and also in the other_hash. That is, we need to turn
1683 * off functions in the other hash because they are disabled
1686 if (filter_hash && in_hash && !in_other_hash)
1688 else if (!filter_hash && in_hash &&
1689 (in_other_hash || ftrace_hash_empty(other_hash)))
1697 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1701 * If there's only a single callback registered to a
1702 * function, and the ops has a trampoline registered
1703 * for it, then we can call it directly.
1705 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1706 rec->flags |= FTRACE_FL_TRAMP;
1709 * If we are adding another function callback
1710 * to this function, and the previous had a
1711 * custom trampoline in use, then we need to go
1712 * back to the default trampoline.
1714 rec->flags &= ~FTRACE_FL_TRAMP;
1717 * If any ops wants regs saved for this function
1718 * then all ops will get saved regs.
1720 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1721 rec->flags |= FTRACE_FL_REGS;
1723 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1728 * If the rec had REGS enabled and the ops that is
1729 * being removed had REGS set, then see if there is
1730 * still any ops for this record that wants regs.
1731 * If not, we can stop recording them.
1733 if (ftrace_rec_count(rec) > 0 &&
1734 rec->flags & FTRACE_FL_REGS &&
1735 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1736 if (!test_rec_ops_needs_regs(rec))
1737 rec->flags &= ~FTRACE_FL_REGS;
1741 * If the rec had TRAMP enabled, then it needs to
1742 * be cleared. As TRAMP can only be enabled iff
1743 * there is only a single ops attached to it.
1744 * In otherwords, always disable it on decrementing.
1745 * In the future, we may set it if rec count is
1746 * decremented to one, and the ops that is left
1749 rec->flags &= ~FTRACE_FL_TRAMP;
1752 * flags will be cleared in ftrace_check_record()
1753 * if rec count is zero.
1758 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1759 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1761 /* Shortcut, if we handled all records, we are done. */
1762 if (!all && count == hash->count)
1764 } while_for_each_ftrace_rec();
1769 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1772 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1775 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1778 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1781 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1782 int filter_hash, int inc)
1784 struct ftrace_ops *op;
1786 __ftrace_hash_rec_update(ops, filter_hash, inc);
1788 if (ops->func_hash != &global_ops.local_hash)
1792 * If the ops shares the global_ops hash, then we need to update
1793 * all ops that are enabled and use this hash.
1795 do_for_each_ftrace_op(op, ftrace_ops_list) {
1799 if (op->func_hash == &global_ops.local_hash)
1800 __ftrace_hash_rec_update(op, filter_hash, inc);
1801 } while_for_each_ftrace_op(op);
1804 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1807 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1810 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1813 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1817 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1818 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1819 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1820 * Note that old_hash and new_hash has below meanings
1821 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1822 * - If the hash is EMPTY_HASH, it hits nothing
1823 * - Anything else hits the recs which match the hash entries.
1825 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1826 struct ftrace_hash *old_hash,
1827 struct ftrace_hash *new_hash)
1829 struct ftrace_page *pg;
1830 struct dyn_ftrace *rec, *end = NULL;
1833 /* Only update if the ops has been registered */
1834 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1837 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1841 * Since the IPMODIFY is a very address sensitive action, we do not
1842 * allow ftrace_ops to set all functions to new hash.
1844 if (!new_hash || !old_hash)
1847 /* Update rec->flags */
1848 do_for_each_ftrace_rec(pg, rec) {
1849 /* We need to update only differences of filter_hash */
1850 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1851 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1852 if (in_old == in_new)
1856 /* New entries must ensure no others are using it */
1857 if (rec->flags & FTRACE_FL_IPMODIFY)
1859 rec->flags |= FTRACE_FL_IPMODIFY;
1860 } else /* Removed entry */
1861 rec->flags &= ~FTRACE_FL_IPMODIFY;
1862 } while_for_each_ftrace_rec();
1869 /* Roll back what we did above */
1870 do_for_each_ftrace_rec(pg, rec) {
1874 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1875 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1876 if (in_old == in_new)
1880 rec->flags &= ~FTRACE_FL_IPMODIFY;
1882 rec->flags |= FTRACE_FL_IPMODIFY;
1883 } while_for_each_ftrace_rec();
1889 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1891 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1893 if (ftrace_hash_empty(hash))
1896 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1899 /* Disabling always succeeds */
1900 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1902 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1904 if (ftrace_hash_empty(hash))
1907 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1910 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1911 struct ftrace_hash *new_hash)
1913 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1915 if (ftrace_hash_empty(old_hash))
1918 if (ftrace_hash_empty(new_hash))
1921 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1924 static void print_ip_ins(const char *fmt, const unsigned char *p)
1928 printk(KERN_CONT "%s", fmt);
1930 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1931 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1934 static struct ftrace_ops *
1935 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1936 static struct ftrace_ops *
1937 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1939 enum ftrace_bug_type ftrace_bug_type;
1940 const void *ftrace_expected;
1942 static void print_bug_type(void)
1944 switch (ftrace_bug_type) {
1945 case FTRACE_BUG_UNKNOWN:
1947 case FTRACE_BUG_INIT:
1948 pr_info("Initializing ftrace call sites\n");
1950 case FTRACE_BUG_NOP:
1951 pr_info("Setting ftrace call site to NOP\n");
1953 case FTRACE_BUG_CALL:
1954 pr_info("Setting ftrace call site to call ftrace function\n");
1956 case FTRACE_BUG_UPDATE:
1957 pr_info("Updating ftrace call site to call a different ftrace function\n");
1963 * ftrace_bug - report and shutdown function tracer
1964 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1965 * @rec: The record that failed
1967 * The arch code that enables or disables the function tracing
1968 * can call ftrace_bug() when it has detected a problem in
1969 * modifying the code. @failed should be one of either:
1970 * EFAULT - if the problem happens on reading the @ip address
1971 * EINVAL - if what is read at @ip is not what was expected
1972 * EPERM - if the problem happens on writting to the @ip address
1974 void ftrace_bug(int failed, struct dyn_ftrace *rec)
1976 unsigned long ip = rec ? rec->ip : 0;
1980 FTRACE_WARN_ON_ONCE(1);
1981 pr_info("ftrace faulted on modifying ");
1985 FTRACE_WARN_ON_ONCE(1);
1986 pr_info("ftrace failed to modify ");
1988 print_ip_ins(" actual: ", (unsigned char *)ip);
1990 if (ftrace_expected) {
1991 print_ip_ins(" expected: ", ftrace_expected);
1996 FTRACE_WARN_ON_ONCE(1);
1997 pr_info("ftrace faulted on writing ");
2001 FTRACE_WARN_ON_ONCE(1);
2002 pr_info("ftrace faulted on unknown error ");
2007 struct ftrace_ops *ops = NULL;
2009 pr_info("ftrace record flags: %lx\n", rec->flags);
2010 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2011 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2012 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2013 ops = ftrace_find_tramp_ops_any(rec);
2016 pr_cont("\ttramp: %pS (%pS)",
2017 (void *)ops->trampoline,
2019 ops = ftrace_find_tramp_ops_next(rec, ops);
2022 pr_cont("\ttramp: ERROR!");
2025 ip = ftrace_get_addr_curr(rec);
2026 pr_cont("\n expected tramp: %lx\n", ip);
2030 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2032 unsigned long flag = 0UL;
2034 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2036 if (rec->flags & FTRACE_FL_DISABLED)
2037 return FTRACE_UPDATE_IGNORE;
2040 * If we are updating calls:
2042 * If the record has a ref count, then we need to enable it
2043 * because someone is using it.
2045 * Otherwise we make sure its disabled.
2047 * If we are disabling calls, then disable all records that
2050 if (enable && ftrace_rec_count(rec))
2051 flag = FTRACE_FL_ENABLED;
2054 * If enabling and the REGS flag does not match the REGS_EN, or
2055 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2056 * this record. Set flags to fail the compare against ENABLED.
2059 if (!(rec->flags & FTRACE_FL_REGS) !=
2060 !(rec->flags & FTRACE_FL_REGS_EN))
2061 flag |= FTRACE_FL_REGS;
2063 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2064 !(rec->flags & FTRACE_FL_TRAMP_EN))
2065 flag |= FTRACE_FL_TRAMP;
2068 /* If the state of this record hasn't changed, then do nothing */
2069 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2070 return FTRACE_UPDATE_IGNORE;
2073 /* Save off if rec is being enabled (for return value) */
2074 flag ^= rec->flags & FTRACE_FL_ENABLED;
2077 rec->flags |= FTRACE_FL_ENABLED;
2078 if (flag & FTRACE_FL_REGS) {
2079 if (rec->flags & FTRACE_FL_REGS)
2080 rec->flags |= FTRACE_FL_REGS_EN;
2082 rec->flags &= ~FTRACE_FL_REGS_EN;
2084 if (flag & FTRACE_FL_TRAMP) {
2085 if (rec->flags & FTRACE_FL_TRAMP)
2086 rec->flags |= FTRACE_FL_TRAMP_EN;
2088 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2093 * If this record is being updated from a nop, then
2094 * return UPDATE_MAKE_CALL.
2096 * return UPDATE_MODIFY_CALL to tell the caller to convert
2097 * from the save regs, to a non-save regs function or
2098 * vice versa, or from a trampoline call.
2100 if (flag & FTRACE_FL_ENABLED) {
2101 ftrace_bug_type = FTRACE_BUG_CALL;
2102 return FTRACE_UPDATE_MAKE_CALL;
2105 ftrace_bug_type = FTRACE_BUG_UPDATE;
2106 return FTRACE_UPDATE_MODIFY_CALL;
2110 /* If there's no more users, clear all flags */
2111 if (!ftrace_rec_count(rec))
2115 * Just disable the record, but keep the ops TRAMP
2116 * and REGS states. The _EN flags must be disabled though.
2118 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2122 ftrace_bug_type = FTRACE_BUG_NOP;
2123 return FTRACE_UPDATE_MAKE_NOP;
2127 * ftrace_update_record, set a record that now is tracing or not
2128 * @rec: the record to update
2129 * @enable: set to 1 if the record is tracing, zero to force disable
2131 * The records that represent all functions that can be traced need
2132 * to be updated when tracing has been enabled.
2134 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2136 return ftrace_check_record(rec, enable, 1);
2140 * ftrace_test_record, check if the record has been enabled or not
2141 * @rec: the record to test
2142 * @enable: set to 1 to check if enabled, 0 if it is disabled
2144 * The arch code may need to test if a record is already set to
2145 * tracing to determine how to modify the function code that it
2148 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2150 return ftrace_check_record(rec, enable, 0);
2153 static struct ftrace_ops *
2154 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2156 struct ftrace_ops *op;
2157 unsigned long ip = rec->ip;
2159 do_for_each_ftrace_op(op, ftrace_ops_list) {
2161 if (!op->trampoline)
2164 if (hash_contains_ip(ip, op->func_hash))
2166 } while_for_each_ftrace_op(op);
2171 static struct ftrace_ops *
2172 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2173 struct ftrace_ops *op)
2175 unsigned long ip = rec->ip;
2177 while_for_each_ftrace_op(op) {
2179 if (!op->trampoline)
2182 if (hash_contains_ip(ip, op->func_hash))
2189 static struct ftrace_ops *
2190 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2192 struct ftrace_ops *op;
2193 unsigned long ip = rec->ip;
2196 * Need to check removed ops first.
2197 * If they are being removed, and this rec has a tramp,
2198 * and this rec is in the ops list, then it would be the
2199 * one with the tramp.
2202 if (hash_contains_ip(ip, &removed_ops->old_hash))
2207 * Need to find the current trampoline for a rec.
2208 * Now, a trampoline is only attached to a rec if there
2209 * was a single 'ops' attached to it. But this can be called
2210 * when we are adding another op to the rec or removing the
2211 * current one. Thus, if the op is being added, we can
2212 * ignore it because it hasn't attached itself to the rec
2215 * If an ops is being modified (hooking to different functions)
2216 * then we don't care about the new functions that are being
2217 * added, just the old ones (that are probably being removed).
2219 * If we are adding an ops to a function that already is using
2220 * a trampoline, it needs to be removed (trampolines are only
2221 * for single ops connected), then an ops that is not being
2222 * modified also needs to be checked.
2224 do_for_each_ftrace_op(op, ftrace_ops_list) {
2226 if (!op->trampoline)
2230 * If the ops is being added, it hasn't gotten to
2231 * the point to be removed from this tree yet.
2233 if (op->flags & FTRACE_OPS_FL_ADDING)
2238 * If the ops is being modified and is in the old
2239 * hash, then it is probably being removed from this
2242 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2243 hash_contains_ip(ip, &op->old_hash))
2246 * If the ops is not being added or modified, and it's
2247 * in its normal filter hash, then this must be the one
2250 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2251 hash_contains_ip(ip, op->func_hash))
2254 } while_for_each_ftrace_op(op);
2259 static struct ftrace_ops *
2260 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2262 struct ftrace_ops *op;
2263 unsigned long ip = rec->ip;
2265 do_for_each_ftrace_op(op, ftrace_ops_list) {
2266 /* pass rec in as regs to have non-NULL val */
2267 if (hash_contains_ip(ip, op->func_hash))
2269 } while_for_each_ftrace_op(op);
2275 * ftrace_get_addr_new - Get the call address to set to
2276 * @rec: The ftrace record descriptor
2278 * If the record has the FTRACE_FL_REGS set, that means that it
2279 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2280 * is not not set, then it wants to convert to the normal callback.
2282 * Returns the address of the trampoline to set to
2284 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2286 struct ftrace_ops *ops;
2288 /* Trampolines take precedence over regs */
2289 if (rec->flags & FTRACE_FL_TRAMP) {
2290 ops = ftrace_find_tramp_ops_new(rec);
2291 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2292 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2293 (void *)rec->ip, (void *)rec->ip, rec->flags);
2294 /* Ftrace is shutting down, return anything */
2295 return (unsigned long)FTRACE_ADDR;
2297 return ops->trampoline;
2300 if (rec->flags & FTRACE_FL_REGS)
2301 return (unsigned long)FTRACE_REGS_ADDR;
2303 return (unsigned long)FTRACE_ADDR;
2307 * ftrace_get_addr_curr - Get the call address that is already there
2308 * @rec: The ftrace record descriptor
2310 * The FTRACE_FL_REGS_EN is set when the record already points to
2311 * a function that saves all the regs. Basically the '_EN' version
2312 * represents the current state of the function.
2314 * Returns the address of the trampoline that is currently being called
2316 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2318 struct ftrace_ops *ops;
2320 /* Trampolines take precedence over regs */
2321 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2322 ops = ftrace_find_tramp_ops_curr(rec);
2323 if (FTRACE_WARN_ON(!ops)) {
2324 pr_warning("Bad trampoline accounting at: %p (%pS)\n",
2325 (void *)rec->ip, (void *)rec->ip);
2326 /* Ftrace is shutting down, return anything */
2327 return (unsigned long)FTRACE_ADDR;
2329 return ops->trampoline;
2332 if (rec->flags & FTRACE_FL_REGS_EN)
2333 return (unsigned long)FTRACE_REGS_ADDR;
2335 return (unsigned long)FTRACE_ADDR;
2339 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2341 unsigned long ftrace_old_addr;
2342 unsigned long ftrace_addr;
2345 ftrace_addr = ftrace_get_addr_new(rec);
2347 /* This needs to be done before we call ftrace_update_record */
2348 ftrace_old_addr = ftrace_get_addr_curr(rec);
2350 ret = ftrace_update_record(rec, enable);
2352 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2355 case FTRACE_UPDATE_IGNORE:
2358 case FTRACE_UPDATE_MAKE_CALL:
2359 ftrace_bug_type = FTRACE_BUG_CALL;
2360 return ftrace_make_call(rec, ftrace_addr);
2362 case FTRACE_UPDATE_MAKE_NOP:
2363 ftrace_bug_type = FTRACE_BUG_NOP;
2364 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2366 case FTRACE_UPDATE_MODIFY_CALL:
2367 ftrace_bug_type = FTRACE_BUG_UPDATE;
2368 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2371 return -1; /* unknow ftrace bug */
2374 void __weak ftrace_replace_code(int enable)
2376 struct dyn_ftrace *rec;
2377 struct ftrace_page *pg;
2380 if (unlikely(ftrace_disabled))
2383 do_for_each_ftrace_rec(pg, rec) {
2384 failed = __ftrace_replace_code(rec, enable);
2386 ftrace_bug(failed, rec);
2387 /* Stop processing */
2390 } while_for_each_ftrace_rec();
2393 struct ftrace_rec_iter {
2394 struct ftrace_page *pg;
2399 * ftrace_rec_iter_start, start up iterating over traced functions
2401 * Returns an iterator handle that is used to iterate over all
2402 * the records that represent address locations where functions
2405 * May return NULL if no records are available.
2407 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2410 * We only use a single iterator.
2411 * Protected by the ftrace_lock mutex.
2413 static struct ftrace_rec_iter ftrace_rec_iter;
2414 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2416 iter->pg = ftrace_pages_start;
2419 /* Could have empty pages */
2420 while (iter->pg && !iter->pg->index)
2421 iter->pg = iter->pg->next;
2430 * ftrace_rec_iter_next, get the next record to process.
2431 * @iter: The handle to the iterator.
2433 * Returns the next iterator after the given iterator @iter.
2435 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2439 if (iter->index >= iter->pg->index) {
2440 iter->pg = iter->pg->next;
2443 /* Could have empty pages */
2444 while (iter->pg && !iter->pg->index)
2445 iter->pg = iter->pg->next;
2455 * ftrace_rec_iter_record, get the record at the iterator location
2456 * @iter: The current iterator location
2458 * Returns the record that the current @iter is at.
2460 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2462 return &iter->pg->records[iter->index];
2466 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2470 if (unlikely(ftrace_disabled))
2473 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2475 ftrace_bug_type = FTRACE_BUG_INIT;
2476 ftrace_bug(ret, rec);
2483 * archs can override this function if they must do something
2484 * before the modifying code is performed.
2486 int __weak ftrace_arch_code_modify_prepare(void)
2492 * archs can override this function if they must do something
2493 * after the modifying code is performed.
2495 int __weak ftrace_arch_code_modify_post_process(void)
2500 void ftrace_modify_all_code(int command)
2502 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2506 * If the ftrace_caller calls a ftrace_ops func directly,
2507 * we need to make sure that it only traces functions it
2508 * expects to trace. When doing the switch of functions,
2509 * we need to update to the ftrace_ops_list_func first
2510 * before the transition between old and new calls are set,
2511 * as the ftrace_ops_list_func will check the ops hashes
2512 * to make sure the ops are having the right functions
2516 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2517 if (FTRACE_WARN_ON(err))
2521 if (command & FTRACE_UPDATE_CALLS)
2522 ftrace_replace_code(1);
2523 else if (command & FTRACE_DISABLE_CALLS)
2524 ftrace_replace_code(0);
2526 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2527 function_trace_op = set_function_trace_op;
2529 /* If irqs are disabled, we are in stop machine */
2530 if (!irqs_disabled())
2531 smp_call_function(ftrace_sync_ipi, NULL, 1);
2532 err = ftrace_update_ftrace_func(ftrace_trace_function);
2533 if (FTRACE_WARN_ON(err))
2537 if (command & FTRACE_START_FUNC_RET)
2538 err = ftrace_enable_ftrace_graph_caller();
2539 else if (command & FTRACE_STOP_FUNC_RET)
2540 err = ftrace_disable_ftrace_graph_caller();
2541 FTRACE_WARN_ON(err);
2544 static int __ftrace_modify_code(void *data)
2546 int *command = data;
2548 ftrace_modify_all_code(*command);
2554 * ftrace_run_stop_machine, go back to the stop machine method
2555 * @command: The command to tell ftrace what to do
2557 * If an arch needs to fall back to the stop machine method, the
2558 * it can call this function.
2560 void ftrace_run_stop_machine(int command)
2562 stop_machine(__ftrace_modify_code, &command, NULL);
2566 * arch_ftrace_update_code, modify the code to trace or not trace
2567 * @command: The command that needs to be done
2569 * Archs can override this function if it does not need to
2570 * run stop_machine() to modify code.
2572 void __weak arch_ftrace_update_code(int command)
2574 ftrace_run_stop_machine(command);
2577 static void ftrace_run_update_code(int command)
2581 ret = ftrace_arch_code_modify_prepare();
2582 FTRACE_WARN_ON(ret);
2587 * By default we use stop_machine() to modify the code.
2588 * But archs can do what ever they want as long as it
2589 * is safe. The stop_machine() is the safest, but also
2590 * produces the most overhead.
2592 arch_ftrace_update_code(command);
2594 ret = ftrace_arch_code_modify_post_process();
2595 FTRACE_WARN_ON(ret);
2598 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2599 struct ftrace_ops_hash *old_hash)
2601 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2602 ops->old_hash.filter_hash = old_hash->filter_hash;
2603 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2604 ftrace_run_update_code(command);
2605 ops->old_hash.filter_hash = NULL;
2606 ops->old_hash.notrace_hash = NULL;
2607 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2610 static ftrace_func_t saved_ftrace_func;
2611 static int ftrace_start_up;
2613 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2617 static void per_cpu_ops_free(struct ftrace_ops *ops)
2619 free_percpu(ops->disabled);
2622 static void ftrace_startup_enable(int command)
2624 if (saved_ftrace_func != ftrace_trace_function) {
2625 saved_ftrace_func = ftrace_trace_function;
2626 command |= FTRACE_UPDATE_TRACE_FUNC;
2629 if (!command || !ftrace_enabled)
2632 ftrace_run_update_code(command);
2635 static void ftrace_startup_all(int command)
2637 update_all_ops = true;
2638 ftrace_startup_enable(command);
2639 update_all_ops = false;
2642 static int ftrace_startup(struct ftrace_ops *ops, int command)
2646 if (unlikely(ftrace_disabled))
2649 ret = __register_ftrace_function(ops);
2654 command |= FTRACE_UPDATE_CALLS;
2657 * Note that ftrace probes uses this to start up
2658 * and modify functions it will probe. But we still
2659 * set the ADDING flag for modification, as probes
2660 * do not have trampolines. If they add them in the
2661 * future, then the probes will need to distinguish
2662 * between adding and updating probes.
2664 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2666 ret = ftrace_hash_ipmodify_enable(ops);
2668 /* Rollback registration process */
2669 __unregister_ftrace_function(ops);
2671 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2675 ftrace_hash_rec_enable(ops, 1);
2677 ftrace_startup_enable(command);
2679 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2684 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2688 if (unlikely(ftrace_disabled))
2691 ret = __unregister_ftrace_function(ops);
2697 * Just warn in case of unbalance, no need to kill ftrace, it's not
2698 * critical but the ftrace_call callers may be never nopped again after
2699 * further ftrace uses.
2701 WARN_ON_ONCE(ftrace_start_up < 0);
2703 /* Disabling ipmodify never fails */
2704 ftrace_hash_ipmodify_disable(ops);
2705 ftrace_hash_rec_disable(ops, 1);
2707 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2709 command |= FTRACE_UPDATE_CALLS;
2711 if (saved_ftrace_func != ftrace_trace_function) {
2712 saved_ftrace_func = ftrace_trace_function;
2713 command |= FTRACE_UPDATE_TRACE_FUNC;
2716 if (!command || !ftrace_enabled) {
2718 * If these are per_cpu ops, they still need their
2719 * per_cpu field freed. Since, function tracing is
2720 * not currently active, we can just free them
2721 * without synchronizing all CPUs.
2723 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2724 per_cpu_ops_free(ops);
2729 * If the ops uses a trampoline, then it needs to be
2730 * tested first on update.
2732 ops->flags |= FTRACE_OPS_FL_REMOVING;
2735 /* The trampoline logic checks the old hashes */
2736 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2737 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2739 ftrace_run_update_code(command);
2742 * If there's no more ops registered with ftrace, run a
2743 * sanity check to make sure all rec flags are cleared.
2745 if (ftrace_ops_list == &ftrace_list_end) {
2746 struct ftrace_page *pg;
2747 struct dyn_ftrace *rec;
2749 do_for_each_ftrace_rec(pg, rec) {
2750 if (FTRACE_WARN_ON_ONCE(rec->flags))
2751 pr_warn(" %pS flags:%lx\n",
2752 (void *)rec->ip, rec->flags);
2753 } while_for_each_ftrace_rec();
2756 ops->old_hash.filter_hash = NULL;
2757 ops->old_hash.notrace_hash = NULL;
2760 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2763 * Dynamic ops may be freed, we must make sure that all
2764 * callers are done before leaving this function.
2765 * The same goes for freeing the per_cpu data of the per_cpu
2768 * Again, normal synchronize_sched() is not good enough.
2769 * We need to do a hard force of sched synchronization.
2770 * This is because we use preempt_disable() to do RCU, but
2771 * the function tracers can be called where RCU is not watching
2772 * (like before user_exit()). We can not rely on the RCU
2773 * infrastructure to do the synchronization, thus we must do it
2776 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2777 schedule_on_each_cpu(ftrace_sync);
2779 arch_ftrace_trampoline_free(ops);
2781 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2782 per_cpu_ops_free(ops);
2788 static void ftrace_startup_sysctl(void)
2792 if (unlikely(ftrace_disabled))
2795 /* Force update next time */
2796 saved_ftrace_func = NULL;
2797 /* ftrace_start_up is true if we want ftrace running */
2798 if (ftrace_start_up) {
2799 command = FTRACE_UPDATE_CALLS;
2800 if (ftrace_graph_active)
2801 command |= FTRACE_START_FUNC_RET;
2802 ftrace_startup_enable(command);
2806 static void ftrace_shutdown_sysctl(void)
2810 if (unlikely(ftrace_disabled))
2813 /* ftrace_start_up is true if ftrace is running */
2814 if (ftrace_start_up) {
2815 command = FTRACE_DISABLE_CALLS;
2816 if (ftrace_graph_active)
2817 command |= FTRACE_STOP_FUNC_RET;
2818 ftrace_run_update_code(command);
2822 static cycle_t ftrace_update_time;
2823 unsigned long ftrace_update_tot_cnt;
2825 static inline int ops_traces_mod(struct ftrace_ops *ops)
2828 * Filter_hash being empty will default to trace module.
2829 * But notrace hash requires a test of individual module functions.
2831 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2832 ftrace_hash_empty(ops->func_hash->notrace_hash);
2836 * Check if the current ops references the record.
2838 * If the ops traces all functions, then it was already accounted for.
2839 * If the ops does not trace the current record function, skip it.
2840 * If the ops ignores the function via notrace filter, skip it.
2843 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2845 /* If ops isn't enabled, ignore it */
2846 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2849 /* If ops traces all then it includes this function */
2850 if (ops_traces_mod(ops))
2853 /* The function must be in the filter */
2854 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2855 !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2858 /* If in notrace hash, we ignore it too */
2859 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2865 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2867 struct ftrace_page *pg;
2868 struct dyn_ftrace *p;
2869 cycle_t start, stop;
2870 unsigned long update_cnt = 0;
2871 unsigned long rec_flags = 0;
2874 start = ftrace_now(raw_smp_processor_id());
2877 * When a module is loaded, this function is called to convert
2878 * the calls to mcount in its text to nops, and also to create
2879 * an entry in the ftrace data. Now, if ftrace is activated
2880 * after this call, but before the module sets its text to
2881 * read-only, the modification of enabling ftrace can fail if
2882 * the read-only is done while ftrace is converting the calls.
2883 * To prevent this, the module's records are set as disabled
2884 * and will be enabled after the call to set the module's text
2888 rec_flags |= FTRACE_FL_DISABLED;
2890 for (pg = new_pgs; pg; pg = pg->next) {
2892 for (i = 0; i < pg->index; i++) {
2894 /* If something went wrong, bail without enabling anything */
2895 if (unlikely(ftrace_disabled))
2898 p = &pg->records[i];
2899 p->flags = rec_flags;
2902 * Do the initial record conversion from mcount jump
2903 * to the NOP instructions.
2905 if (!ftrace_code_disable(mod, p))
2912 stop = ftrace_now(raw_smp_processor_id());
2913 ftrace_update_time = stop - start;
2914 ftrace_update_tot_cnt += update_cnt;
2919 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2924 if (WARN_ON(!count))
2927 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2930 * We want to fill as much as possible. No more than a page
2933 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2937 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2940 /* if we can't allocate this size, try something smaller */
2947 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2956 static struct ftrace_page *
2957 ftrace_allocate_pages(unsigned long num_to_init)
2959 struct ftrace_page *start_pg;
2960 struct ftrace_page *pg;
2967 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2972 * Try to allocate as much as possible in one continues
2973 * location that fills in all of the space. We want to
2974 * waste as little space as possible.
2977 cnt = ftrace_allocate_records(pg, num_to_init);
2985 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2997 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2998 free_pages((unsigned long)pg->records, order);
2999 start_pg = pg->next;
3003 pr_info("ftrace: FAILED to allocate memory for functions\n");
3007 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3009 struct ftrace_iterator {
3012 struct ftrace_page *pg;
3013 struct dyn_ftrace *func;
3014 struct ftrace_func_probe *probe;
3015 struct trace_parser parser;
3016 struct ftrace_hash *hash;
3017 struct ftrace_ops *ops;
3024 t_hash_next(struct seq_file *m, loff_t *pos)
3026 struct ftrace_iterator *iter = m->private;
3027 struct hlist_node *hnd = NULL;
3028 struct hlist_head *hhd;
3034 hnd = &iter->probe->node;
3036 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3039 hhd = &ftrace_func_hash[iter->hidx];
3041 if (hlist_empty(hhd)) {
3057 if (WARN_ON_ONCE(!hnd))
3060 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3065 static void *t_hash_start(struct seq_file *m, loff_t *pos)
3067 struct ftrace_iterator *iter = m->private;
3071 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3074 if (iter->func_pos > *pos)
3078 for (l = 0; l <= (*pos - iter->func_pos); ) {
3079 p = t_hash_next(m, &l);
3086 /* Only set this if we have an item */
3087 iter->flags |= FTRACE_ITER_HASH;
3093 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3095 struct ftrace_func_probe *rec;
3098 if (WARN_ON_ONCE(!rec))
3101 if (rec->ops->print)
3102 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3104 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3107 seq_printf(m, ":%p", rec->data);
3114 t_next(struct seq_file *m, void *v, loff_t *pos)
3116 struct ftrace_iterator *iter = m->private;
3117 struct ftrace_ops *ops = iter->ops;
3118 struct dyn_ftrace *rec = NULL;
3120 if (unlikely(ftrace_disabled))
3123 if (iter->flags & FTRACE_ITER_HASH)
3124 return t_hash_next(m, pos);
3127 iter->pos = iter->func_pos = *pos;
3129 if (iter->flags & FTRACE_ITER_PRINTALL)
3130 return t_hash_start(m, pos);
3133 if (iter->idx >= iter->pg->index) {
3134 if (iter->pg->next) {
3135 iter->pg = iter->pg->next;
3140 rec = &iter->pg->records[iter->idx++];
3141 if (((iter->flags & FTRACE_ITER_FILTER) &&
3142 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3144 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3145 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3147 ((iter->flags & FTRACE_ITER_ENABLED) &&
3148 !(rec->flags & FTRACE_FL_ENABLED))) {
3156 return t_hash_start(m, pos);
3163 static void reset_iter_read(struct ftrace_iterator *iter)
3167 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3170 static void *t_start(struct seq_file *m, loff_t *pos)
3172 struct ftrace_iterator *iter = m->private;
3173 struct ftrace_ops *ops = iter->ops;
3177 mutex_lock(&ftrace_lock);
3179 if (unlikely(ftrace_disabled))
3183 * If an lseek was done, then reset and start from beginning.
3185 if (*pos < iter->pos)
3186 reset_iter_read(iter);
3189 * For set_ftrace_filter reading, if we have the filter
3190 * off, we can short cut and just print out that all
3191 * functions are enabled.
3193 if ((iter->flags & FTRACE_ITER_FILTER &&
3194 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3195 (iter->flags & FTRACE_ITER_NOTRACE &&
3196 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3198 return t_hash_start(m, pos);
3199 iter->flags |= FTRACE_ITER_PRINTALL;
3200 /* reset in case of seek/pread */
3201 iter->flags &= ~FTRACE_ITER_HASH;
3205 if (iter->flags & FTRACE_ITER_HASH)
3206 return t_hash_start(m, pos);
3209 * Unfortunately, we need to restart at ftrace_pages_start
3210 * every time we let go of the ftrace_mutex. This is because
3211 * those pointers can change without the lock.
3213 iter->pg = ftrace_pages_start;
3215 for (l = 0; l <= *pos; ) {
3216 p = t_next(m, p, &l);
3222 return t_hash_start(m, pos);
3227 static void t_stop(struct seq_file *m, void *p)
3229 mutex_unlock(&ftrace_lock);
3233 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3238 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3239 struct dyn_ftrace *rec)
3243 ptr = arch_ftrace_trampoline_func(ops, rec);
3245 seq_printf(m, " ->%pS", ptr);
3248 static int t_show(struct seq_file *m, void *v)
3250 struct ftrace_iterator *iter = m->private;
3251 struct dyn_ftrace *rec;
3253 if (iter->flags & FTRACE_ITER_HASH)
3254 return t_hash_show(m, iter);
3256 if (iter->flags & FTRACE_ITER_PRINTALL) {
3257 if (iter->flags & FTRACE_ITER_NOTRACE)
3258 seq_puts(m, "#### no functions disabled ####\n");
3260 seq_puts(m, "#### all functions enabled ####\n");
3269 seq_printf(m, "%ps", (void *)rec->ip);
3270 if (iter->flags & FTRACE_ITER_ENABLED) {
3271 struct ftrace_ops *ops;
3273 seq_printf(m, " (%ld)%s%s",
3274 ftrace_rec_count(rec),
3275 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3276 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3277 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3278 ops = ftrace_find_tramp_ops_any(rec);
3281 seq_printf(m, "\ttramp: %pS (%pS)",
3282 (void *)ops->trampoline,
3284 add_trampoline_func(m, ops, rec);
3285 ops = ftrace_find_tramp_ops_next(rec, ops);
3288 seq_puts(m, "\ttramp: ERROR!");
3290 add_trampoline_func(m, NULL, rec);
3299 static const struct seq_operations show_ftrace_seq_ops = {
3307 ftrace_avail_open(struct inode *inode, struct file *file)
3309 struct ftrace_iterator *iter;
3311 if (unlikely(ftrace_disabled))
3314 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3316 iter->pg = ftrace_pages_start;
3317 iter->ops = &global_ops;
3320 return iter ? 0 : -ENOMEM;
3324 ftrace_enabled_open(struct inode *inode, struct file *file)
3326 struct ftrace_iterator *iter;
3328 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3330 iter->pg = ftrace_pages_start;
3331 iter->flags = FTRACE_ITER_ENABLED;
3332 iter->ops = &global_ops;
3335 return iter ? 0 : -ENOMEM;
3339 * ftrace_regex_open - initialize function tracer filter files
3340 * @ops: The ftrace_ops that hold the hash filters
3341 * @flag: The type of filter to process
3342 * @inode: The inode, usually passed in to your open routine
3343 * @file: The file, usually passed in to your open routine
3345 * ftrace_regex_open() initializes the filter files for the
3346 * @ops. Depending on @flag it may process the filter hash or
3347 * the notrace hash of @ops. With this called from the open
3348 * routine, you can use ftrace_filter_write() for the write
3349 * routine if @flag has FTRACE_ITER_FILTER set, or
3350 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3351 * tracing_lseek() should be used as the lseek routine, and
3352 * release must call ftrace_regex_release().
3355 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3356 struct inode *inode, struct file *file)
3358 struct ftrace_iterator *iter;
3359 struct ftrace_hash *hash;
3362 ftrace_ops_init(ops);
3364 if (unlikely(ftrace_disabled))
3367 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3371 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3379 mutex_lock(&ops->func_hash->regex_lock);
3381 if (flag & FTRACE_ITER_NOTRACE)
3382 hash = ops->func_hash->notrace_hash;
3384 hash = ops->func_hash->filter_hash;
3386 if (file->f_mode & FMODE_WRITE) {
3387 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3389 if (file->f_flags & O_TRUNC)
3390 iter->hash = alloc_ftrace_hash(size_bits);
3392 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3395 trace_parser_put(&iter->parser);
3402 if (file->f_mode & FMODE_READ) {
3403 iter->pg = ftrace_pages_start;
3405 ret = seq_open(file, &show_ftrace_seq_ops);
3407 struct seq_file *m = file->private_data;
3411 free_ftrace_hash(iter->hash);
3412 trace_parser_put(&iter->parser);
3416 file->private_data = iter;
3419 mutex_unlock(&ops->func_hash->regex_lock);
3425 ftrace_filter_open(struct inode *inode, struct file *file)
3427 struct ftrace_ops *ops = inode->i_private;
3429 return ftrace_regex_open(ops,
3430 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3435 ftrace_notrace_open(struct inode *inode, struct file *file)
3437 struct ftrace_ops *ops = inode->i_private;
3439 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3443 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3444 struct ftrace_glob {
3450 static int ftrace_match(char *str, struct ftrace_glob *g)
3457 if (strcmp(str, g->search) == 0)
3460 case MATCH_FRONT_ONLY:
3461 if (strncmp(str, g->search, g->len) == 0)
3464 case MATCH_MIDDLE_ONLY:
3465 if (strstr(str, g->search))
3468 case MATCH_END_ONLY:
3470 if (slen >= g->len &&
3471 memcmp(str + slen - g->len, g->search, g->len) == 0)
3480 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3482 struct ftrace_func_entry *entry;
3485 entry = ftrace_lookup_ip(hash, rec->ip);
3487 /* Do nothing if it doesn't exist */
3491 free_hash_entry(hash, entry);
3493 /* Do nothing if it exists */
3497 ret = add_hash_entry(hash, rec->ip);
3503 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3504 struct ftrace_glob *mod_g, int exclude_mod)
3506 char str[KSYM_SYMBOL_LEN];
3509 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3512 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3514 /* blank module name to match all modules */
3516 /* blank module globbing: modname xor exclude_mod */
3517 if ((!exclude_mod) != (!modname))
3522 /* not matching the module */
3523 if (!modname || !mod_matches) {
3530 if (mod_matches && exclude_mod)
3534 /* blank search means to match all funcs in the mod */
3539 return ftrace_match(str, func_g);
3543 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3545 struct ftrace_page *pg;
3546 struct dyn_ftrace *rec;
3547 struct ftrace_glob func_g = { .type = MATCH_FULL };
3548 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3549 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3550 int exclude_mod = 0;
3556 func_g.type = filter_parse_regex(func, len, &func_g.search,
3558 func_g.len = strlen(func_g.search);
3562 mod_g.type = filter_parse_regex(mod, strlen(mod),
3563 &mod_g.search, &exclude_mod);
3564 mod_g.len = strlen(mod_g.search);
3567 mutex_lock(&ftrace_lock);
3569 if (unlikely(ftrace_disabled))
3572 do_for_each_ftrace_rec(pg, rec) {
3573 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3574 ret = enter_record(hash, rec, clear_filter);
3581 } while_for_each_ftrace_rec();
3583 mutex_unlock(&ftrace_lock);
3589 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3591 return match_records(hash, buff, len, NULL);
3596 * We register the module command as a template to show others how
3597 * to register the a command as well.
3601 ftrace_mod_callback(struct ftrace_hash *hash,
3602 char *func, char *cmd, char *module, int enable)
3607 * cmd == 'mod' because we only registered this func
3608 * for the 'mod' ftrace_func_command.
3609 * But if you register one func with multiple commands,
3610 * you can tell which command was used by the cmd
3613 ret = match_records(hash, func, strlen(func), module);
3621 static struct ftrace_func_command ftrace_mod_cmd = {
3623 .func = ftrace_mod_callback,
3626 static int __init ftrace_mod_cmd_init(void)
3628 return register_ftrace_command(&ftrace_mod_cmd);
3630 core_initcall(ftrace_mod_cmd_init);
3632 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3633 struct ftrace_ops *op, struct pt_regs *pt_regs)
3635 struct ftrace_func_probe *entry;
3636 struct hlist_head *hhd;
3639 key = hash_long(ip, FTRACE_HASH_BITS);
3641 hhd = &ftrace_func_hash[key];
3643 if (hlist_empty(hhd))
3647 * Disable preemption for these calls to prevent a RCU grace
3648 * period. This syncs the hash iteration and freeing of items
3649 * on the hash. rcu_read_lock is too dangerous here.
3651 preempt_disable_notrace();
3652 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3653 if (entry->ip == ip)
3654 entry->ops->func(ip, parent_ip, &entry->data);
3656 preempt_enable_notrace();
3659 static struct ftrace_ops trace_probe_ops __read_mostly =
3661 .func = function_trace_probe_call,
3662 .flags = FTRACE_OPS_FL_INITIALIZED,
3663 INIT_OPS_HASH(trace_probe_ops)
3666 static int ftrace_probe_registered;
3668 static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3673 if (ftrace_probe_registered) {
3674 /* still need to update the function call sites */
3676 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3681 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3682 struct hlist_head *hhd = &ftrace_func_hash[i];
3686 /* Nothing registered? */
3687 if (i == FTRACE_FUNC_HASHSIZE)
3690 ret = ftrace_startup(&trace_probe_ops, 0);
3692 ftrace_probe_registered = 1;
3695 static void __disable_ftrace_function_probe(void)
3699 if (!ftrace_probe_registered)
3702 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3703 struct hlist_head *hhd = &ftrace_func_hash[i];
3708 /* no more funcs left */
3709 ftrace_shutdown(&trace_probe_ops, 0);
3711 ftrace_probe_registered = 0;
3715 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3717 if (entry->ops->free)
3718 entry->ops->free(entry->ops, entry->ip, &entry->data);
3723 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3726 struct ftrace_ops_hash old_hash_ops;
3727 struct ftrace_func_probe *entry;
3728 struct ftrace_glob func_g;
3729 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3730 struct ftrace_hash *old_hash = *orig_hash;
3731 struct ftrace_hash *hash;
3732 struct ftrace_page *pg;
3733 struct dyn_ftrace *rec;
3739 func_g.type = filter_parse_regex(glob, strlen(glob),
3740 &func_g.search, ¬);
3741 func_g.len = strlen(func_g.search);
3743 /* we do not support '!' for function probes */
3747 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3749 old_hash_ops.filter_hash = old_hash;
3750 /* Probes only have filters */
3751 old_hash_ops.notrace_hash = NULL;
3753 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3759 if (unlikely(ftrace_disabled)) {
3764 mutex_lock(&ftrace_lock);
3766 do_for_each_ftrace_rec(pg, rec) {
3768 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3771 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3773 /* If we did not process any, then return error */
3784 * The caller might want to do something special
3785 * for each function we find. We call the callback
3786 * to give the caller an opportunity to do so.
3789 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3790 /* caller does not like this func */
3796 ret = enter_record(hash, rec, 0);
3804 entry->ip = rec->ip;
3806 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3807 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3809 } while_for_each_ftrace_rec();
3811 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3813 __enable_ftrace_function_probe(&old_hash_ops);
3816 free_ftrace_hash_rcu(old_hash);
3821 mutex_unlock(&ftrace_lock);
3823 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3824 free_ftrace_hash(hash);
3830 PROBE_TEST_FUNC = 1,
3835 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3836 void *data, int flags)
3838 struct ftrace_func_entry *rec_entry;
3839 struct ftrace_func_probe *entry;
3840 struct ftrace_func_probe *p;
3841 struct ftrace_glob func_g;
3842 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3843 struct ftrace_hash *old_hash = *orig_hash;
3844 struct list_head free_list;
3845 struct ftrace_hash *hash;
3846 struct hlist_node *tmp;
3847 char str[KSYM_SYMBOL_LEN];
3850 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3851 func_g.search = NULL;
3855 func_g.type = filter_parse_regex(glob, strlen(glob),
3856 &func_g.search, ¬);
3857 func_g.len = strlen(func_g.search);
3858 func_g.search = glob;
3860 /* we do not support '!' for function probes */
3865 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3867 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3869 /* Hmm, should report this somehow */
3872 INIT_LIST_HEAD(&free_list);
3874 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3875 struct hlist_head *hhd = &ftrace_func_hash[i];
3877 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3879 /* break up if statements for readability */
3880 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3883 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3886 /* do this last, since it is the most expensive */
3887 if (func_g.search) {
3888 kallsyms_lookup(entry->ip, NULL, NULL,
3890 if (!ftrace_match(str, &func_g))
3894 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3895 /* It is possible more than one entry had this ip */
3897 free_hash_entry(hash, rec_entry);
3899 hlist_del_rcu(&entry->node);
3900 list_add(&entry->free_list, &free_list);
3903 mutex_lock(&ftrace_lock);
3904 __disable_ftrace_function_probe();
3906 * Remove after the disable is called. Otherwise, if the last
3907 * probe is removed, a null hash means *all enabled*.
3909 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3910 synchronize_sched();
3912 free_ftrace_hash_rcu(old_hash);
3914 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3915 list_del(&entry->free_list);
3916 ftrace_free_entry(entry);
3918 mutex_unlock(&ftrace_lock);
3921 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3922 free_ftrace_hash(hash);
3926 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3929 __unregister_ftrace_function_probe(glob, ops, data,
3930 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3934 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3936 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3939 void unregister_ftrace_function_probe_all(char *glob)
3941 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3944 static LIST_HEAD(ftrace_commands);
3945 static DEFINE_MUTEX(ftrace_cmd_mutex);
3948 * Currently we only register ftrace commands from __init, so mark this
3951 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3953 struct ftrace_func_command *p;
3956 mutex_lock(&ftrace_cmd_mutex);
3957 list_for_each_entry(p, &ftrace_commands, list) {
3958 if (strcmp(cmd->name, p->name) == 0) {
3963 list_add(&cmd->list, &ftrace_commands);
3965 mutex_unlock(&ftrace_cmd_mutex);
3971 * Currently we only unregister ftrace commands from __init, so mark
3974 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3976 struct ftrace_func_command *p, *n;
3979 mutex_lock(&ftrace_cmd_mutex);
3980 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3981 if (strcmp(cmd->name, p->name) == 0) {
3983 list_del_init(&p->list);
3988 mutex_unlock(&ftrace_cmd_mutex);
3993 static int ftrace_process_regex(struct ftrace_hash *hash,
3994 char *buff, int len, int enable)
3996 char *func, *command, *next = buff;
3997 struct ftrace_func_command *p;
4000 func = strsep(&next, ":");
4003 ret = ftrace_match_records(hash, func, len);
4013 command = strsep(&next, ":");
4015 mutex_lock(&ftrace_cmd_mutex);
4016 list_for_each_entry(p, &ftrace_commands, list) {
4017 if (strcmp(p->name, command) == 0) {
4018 ret = p->func(hash, func, command, next, enable);
4023 mutex_unlock(&ftrace_cmd_mutex);
4029 ftrace_regex_write(struct file *file, const char __user *ubuf,
4030 size_t cnt, loff_t *ppos, int enable)
4032 struct ftrace_iterator *iter;
4033 struct trace_parser *parser;
4039 if (file->f_mode & FMODE_READ) {
4040 struct seq_file *m = file->private_data;
4043 iter = file->private_data;
4045 if (unlikely(ftrace_disabled))
4048 /* iter->hash is a local copy, so we don't need regex_lock */
4050 parser = &iter->parser;
4051 read = trace_get_user(parser, ubuf, cnt, ppos);
4053 if (read >= 0 && trace_parser_loaded(parser) &&
4054 !trace_parser_cont(parser)) {
4055 ret = ftrace_process_regex(iter->hash, parser->buffer,
4056 parser->idx, enable);
4057 trace_parser_clear(parser);
4068 ftrace_filter_write(struct file *file, const char __user *ubuf,
4069 size_t cnt, loff_t *ppos)
4071 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4075 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4076 size_t cnt, loff_t *ppos)
4078 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4082 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4084 struct ftrace_func_entry *entry;
4086 if (!ftrace_location(ip))
4090 entry = ftrace_lookup_ip(hash, ip);
4093 free_hash_entry(hash, entry);
4097 return add_hash_entry(hash, ip);
4100 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4101 struct ftrace_ops_hash *old_hash)
4103 struct ftrace_ops *op;
4105 if (!ftrace_enabled)
4108 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4109 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4114 * If this is the shared global_ops filter, then we need to
4115 * check if there is another ops that shares it, is enabled.
4116 * If so, we still need to run the modify code.
4118 if (ops->func_hash != &global_ops.local_hash)
4121 do_for_each_ftrace_op(op, ftrace_ops_list) {
4122 if (op->func_hash == &global_ops.local_hash &&
4123 op->flags & FTRACE_OPS_FL_ENABLED) {
4124 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4125 /* Only need to do this once */
4128 } while_for_each_ftrace_op(op);
4132 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4133 unsigned long ip, int remove, int reset, int enable)
4135 struct ftrace_hash **orig_hash;
4136 struct ftrace_ops_hash old_hash_ops;
4137 struct ftrace_hash *old_hash;
4138 struct ftrace_hash *hash;
4141 if (unlikely(ftrace_disabled))
4144 mutex_lock(&ops->func_hash->regex_lock);
4147 orig_hash = &ops->func_hash->filter_hash;
4149 orig_hash = &ops->func_hash->notrace_hash;
4152 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4154 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4158 goto out_regex_unlock;
4161 if (buf && !ftrace_match_records(hash, buf, len)) {
4163 goto out_regex_unlock;
4166 ret = ftrace_match_addr(hash, ip, remove);
4168 goto out_regex_unlock;
4171 mutex_lock(&ftrace_lock);
4172 old_hash = *orig_hash;
4173 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4174 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4175 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4177 ftrace_ops_update_code(ops, &old_hash_ops);
4178 free_ftrace_hash_rcu(old_hash);
4180 mutex_unlock(&ftrace_lock);
4183 mutex_unlock(&ops->func_hash->regex_lock);
4185 free_ftrace_hash(hash);
4190 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4191 int reset, int enable)
4193 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4197 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4198 * @ops - the ops to set the filter with
4199 * @ip - the address to add to or remove from the filter.
4200 * @remove - non zero to remove the ip from the filter
4201 * @reset - non zero to reset all filters before applying this filter.
4203 * Filters denote which functions should be enabled when tracing is enabled
4204 * If @ip is NULL, it failes to update filter.
4206 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4207 int remove, int reset)
4209 ftrace_ops_init(ops);
4210 return ftrace_set_addr(ops, ip, remove, reset, 1);
4212 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4215 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4216 int reset, int enable)
4218 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4222 * ftrace_set_filter - set a function to filter on in ftrace
4223 * @ops - the ops to set the filter with
4224 * @buf - the string that holds the function filter text.
4225 * @len - the length of the string.
4226 * @reset - non zero to reset all filters before applying this filter.
4228 * Filters denote which functions should be enabled when tracing is enabled.
4229 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4231 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4234 ftrace_ops_init(ops);
4235 return ftrace_set_regex(ops, buf, len, reset, 1);
4237 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4240 * ftrace_set_notrace - set a function to not trace in ftrace
4241 * @ops - the ops to set the notrace filter with
4242 * @buf - the string that holds the function notrace text.
4243 * @len - the length of the string.
4244 * @reset - non zero to reset all filters before applying this filter.
4246 * Notrace Filters denote which functions should not be enabled when tracing
4247 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4250 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4253 ftrace_ops_init(ops);
4254 return ftrace_set_regex(ops, buf, len, reset, 0);
4256 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4258 * ftrace_set_global_filter - set a function to filter on with global tracers
4259 * @buf - the string that holds the function filter text.
4260 * @len - the length of the string.
4261 * @reset - non zero to reset all filters before applying this filter.
4263 * Filters denote which functions should be enabled when tracing is enabled.
4264 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4266 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4268 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4270 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4273 * ftrace_set_global_notrace - set a function to not trace with global tracers
4274 * @buf - the string that holds the function notrace text.
4275 * @len - the length of the string.
4276 * @reset - non zero to reset all filters before applying this filter.
4278 * Notrace Filters denote which functions should not be enabled when tracing
4279 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4282 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4284 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4286 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4289 * command line interface to allow users to set filters on boot up.
4291 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4292 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4293 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4295 /* Used by function selftest to not test if filter is set */
4296 bool ftrace_filter_param __initdata;
4298 static int __init set_ftrace_notrace(char *str)
4300 ftrace_filter_param = true;
4301 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4304 __setup("ftrace_notrace=", set_ftrace_notrace);
4306 static int __init set_ftrace_filter(char *str)
4308 ftrace_filter_param = true;
4309 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4312 __setup("ftrace_filter=", set_ftrace_filter);
4314 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4315 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4316 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4317 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4319 static unsigned long save_global_trampoline;
4320 static unsigned long save_global_flags;
4322 static int __init set_graph_function(char *str)
4324 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4327 __setup("ftrace_graph_filter=", set_graph_function);
4329 static int __init set_graph_notrace_function(char *str)
4331 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4334 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4336 static void __init set_ftrace_early_graph(char *buf, int enable)
4340 unsigned long *table = ftrace_graph_funcs;
4341 int *count = &ftrace_graph_count;
4344 table = ftrace_graph_notrace_funcs;
4345 count = &ftrace_graph_notrace_count;
4349 func = strsep(&buf, ",");
4350 /* we allow only one expression at a time */
4351 ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4353 printk(KERN_DEBUG "ftrace: function %s not "
4354 "traceable\n", func);
4357 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4360 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4364 ftrace_ops_init(ops);
4367 func = strsep(&buf, ",");
4368 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4372 static void __init set_ftrace_early_filters(void)
4374 if (ftrace_filter_buf[0])
4375 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4376 if (ftrace_notrace_buf[0])
4377 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4378 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4379 if (ftrace_graph_buf[0])
4380 set_ftrace_early_graph(ftrace_graph_buf, 1);
4381 if (ftrace_graph_notrace_buf[0])
4382 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4383 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4386 int ftrace_regex_release(struct inode *inode, struct file *file)
4388 struct seq_file *m = (struct seq_file *)file->private_data;
4389 struct ftrace_ops_hash old_hash_ops;
4390 struct ftrace_iterator *iter;
4391 struct ftrace_hash **orig_hash;
4392 struct ftrace_hash *old_hash;
4393 struct trace_parser *parser;
4397 if (file->f_mode & FMODE_READ) {
4399 seq_release(inode, file);
4401 iter = file->private_data;
4403 parser = &iter->parser;
4404 if (trace_parser_loaded(parser)) {
4405 parser->buffer[parser->idx] = 0;
4406 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4409 trace_parser_put(parser);
4411 mutex_lock(&iter->ops->func_hash->regex_lock);
4413 if (file->f_mode & FMODE_WRITE) {
4414 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4417 orig_hash = &iter->ops->func_hash->filter_hash;
4419 orig_hash = &iter->ops->func_hash->notrace_hash;
4421 mutex_lock(&ftrace_lock);
4422 old_hash = *orig_hash;
4423 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4424 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4425 ret = ftrace_hash_move(iter->ops, filter_hash,
4426 orig_hash, iter->hash);
4428 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4429 free_ftrace_hash_rcu(old_hash);
4431 mutex_unlock(&ftrace_lock);
4434 mutex_unlock(&iter->ops->func_hash->regex_lock);
4435 free_ftrace_hash(iter->hash);
4441 static const struct file_operations ftrace_avail_fops = {
4442 .open = ftrace_avail_open,
4444 .llseek = seq_lseek,
4445 .release = seq_release_private,
4448 static const struct file_operations ftrace_enabled_fops = {
4449 .open = ftrace_enabled_open,
4451 .llseek = seq_lseek,
4452 .release = seq_release_private,
4455 static const struct file_operations ftrace_filter_fops = {
4456 .open = ftrace_filter_open,
4458 .write = ftrace_filter_write,
4459 .llseek = tracing_lseek,
4460 .release = ftrace_regex_release,
4463 static const struct file_operations ftrace_notrace_fops = {
4464 .open = ftrace_notrace_open,
4466 .write = ftrace_notrace_write,
4467 .llseek = tracing_lseek,
4468 .release = ftrace_regex_release,
4471 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4473 static DEFINE_MUTEX(graph_lock);
4475 int ftrace_graph_count;
4476 int ftrace_graph_notrace_count;
4477 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4478 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4480 struct ftrace_graph_data {
4481 unsigned long *table;
4484 const struct seq_operations *seq_ops;
4488 __g_next(struct seq_file *m, loff_t *pos)
4490 struct ftrace_graph_data *fgd = m->private;
4492 if (*pos >= *fgd->count)
4494 return &fgd->table[*pos];
4498 g_next(struct seq_file *m, void *v, loff_t *pos)
4501 return __g_next(m, pos);
4504 static void *g_start(struct seq_file *m, loff_t *pos)
4506 struct ftrace_graph_data *fgd = m->private;
4508 mutex_lock(&graph_lock);
4510 /* Nothing, tell g_show to print all functions are enabled */
4511 if (!*fgd->count && !*pos)
4514 return __g_next(m, pos);
4517 static void g_stop(struct seq_file *m, void *p)
4519 mutex_unlock(&graph_lock);
4522 static int g_show(struct seq_file *m, void *v)
4524 unsigned long *ptr = v;
4529 if (ptr == (unsigned long *)1) {
4530 struct ftrace_graph_data *fgd = m->private;
4532 if (fgd->table == ftrace_graph_funcs)
4533 seq_puts(m, "#### all functions enabled ####\n");
4535 seq_puts(m, "#### no functions disabled ####\n");
4539 seq_printf(m, "%ps\n", (void *)*ptr);
4544 static const struct seq_operations ftrace_graph_seq_ops = {
4552 __ftrace_graph_open(struct inode *inode, struct file *file,
4553 struct ftrace_graph_data *fgd)
4557 mutex_lock(&graph_lock);
4558 if ((file->f_mode & FMODE_WRITE) &&
4559 (file->f_flags & O_TRUNC)) {
4561 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4563 mutex_unlock(&graph_lock);
4565 if (file->f_mode & FMODE_READ) {
4566 ret = seq_open(file, fgd->seq_ops);
4568 struct seq_file *m = file->private_data;
4572 file->private_data = fgd;
4578 ftrace_graph_open(struct inode *inode, struct file *file)
4580 struct ftrace_graph_data *fgd;
4582 if (unlikely(ftrace_disabled))
4585 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4589 fgd->table = ftrace_graph_funcs;
4590 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4591 fgd->count = &ftrace_graph_count;
4592 fgd->seq_ops = &ftrace_graph_seq_ops;
4594 return __ftrace_graph_open(inode, file, fgd);
4598 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4600 struct ftrace_graph_data *fgd;
4602 if (unlikely(ftrace_disabled))
4605 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4609 fgd->table = ftrace_graph_notrace_funcs;
4610 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4611 fgd->count = &ftrace_graph_notrace_count;
4612 fgd->seq_ops = &ftrace_graph_seq_ops;
4614 return __ftrace_graph_open(inode, file, fgd);
4618 ftrace_graph_release(struct inode *inode, struct file *file)
4620 if (file->f_mode & FMODE_READ) {
4621 struct seq_file *m = file->private_data;
4624 seq_release(inode, file);
4626 kfree(file->private_data);
4633 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4635 struct ftrace_glob func_g;
4636 struct dyn_ftrace *rec;
4637 struct ftrace_page *pg;
4644 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4645 &func_g.search, ¬);
4646 if (!not && *idx >= size)
4649 func_g.len = strlen(func_g.search);
4651 mutex_lock(&ftrace_lock);
4653 if (unlikely(ftrace_disabled)) {
4654 mutex_unlock(&ftrace_lock);
4658 do_for_each_ftrace_rec(pg, rec) {
4660 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4661 /* if it is in the array */
4663 for (i = 0; i < *idx; i++) {
4664 if (array[i] == rec->ip) {
4673 array[(*idx)++] = rec->ip;
4679 array[i] = array[--(*idx)];
4685 } while_for_each_ftrace_rec();
4687 mutex_unlock(&ftrace_lock);
4696 ftrace_graph_write(struct file *file, const char __user *ubuf,
4697 size_t cnt, loff_t *ppos)
4699 struct trace_parser parser;
4700 ssize_t read, ret = 0;
4701 struct ftrace_graph_data *fgd = file->private_data;
4706 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4709 read = trace_get_user(&parser, ubuf, cnt, ppos);
4711 if (read >= 0 && trace_parser_loaded((&parser))) {
4712 parser.buffer[parser.idx] = 0;
4714 mutex_lock(&graph_lock);
4716 /* we allow only one expression at a time */
4717 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4720 mutex_unlock(&graph_lock);
4726 trace_parser_put(&parser);
4731 static const struct file_operations ftrace_graph_fops = {
4732 .open = ftrace_graph_open,
4734 .write = ftrace_graph_write,
4735 .llseek = tracing_lseek,
4736 .release = ftrace_graph_release,
4739 static const struct file_operations ftrace_graph_notrace_fops = {
4740 .open = ftrace_graph_notrace_open,
4742 .write = ftrace_graph_write,
4743 .llseek = tracing_lseek,
4744 .release = ftrace_graph_release,
4746 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4748 void ftrace_create_filter_files(struct ftrace_ops *ops,
4749 struct dentry *parent)
4752 trace_create_file("set_ftrace_filter", 0644, parent,
4753 ops, &ftrace_filter_fops);
4755 trace_create_file("set_ftrace_notrace", 0644, parent,
4756 ops, &ftrace_notrace_fops);
4760 * The name "destroy_filter_files" is really a misnomer. Although
4761 * in the future, it may actualy delete the files, but this is
4762 * really intended to make sure the ops passed in are disabled
4763 * and that when this function returns, the caller is free to
4766 * The "destroy" name is only to match the "create" name that this
4767 * should be paired with.
4769 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4771 mutex_lock(&ftrace_lock);
4772 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4773 ftrace_shutdown(ops, 0);
4774 ops->flags |= FTRACE_OPS_FL_DELETED;
4775 mutex_unlock(&ftrace_lock);
4778 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4781 trace_create_file("available_filter_functions", 0444,
4782 d_tracer, NULL, &ftrace_avail_fops);
4784 trace_create_file("enabled_functions", 0444,
4785 d_tracer, NULL, &ftrace_enabled_fops);
4787 ftrace_create_filter_files(&global_ops, d_tracer);
4789 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4790 trace_create_file("set_graph_function", 0444, d_tracer,
4792 &ftrace_graph_fops);
4793 trace_create_file("set_graph_notrace", 0444, d_tracer,
4795 &ftrace_graph_notrace_fops);
4796 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4801 static int ftrace_cmp_ips(const void *a, const void *b)
4803 const unsigned long *ipa = a;
4804 const unsigned long *ipb = b;
4813 static int ftrace_process_locs(struct module *mod,
4814 unsigned long *start,
4817 struct ftrace_page *start_pg;
4818 struct ftrace_page *pg;
4819 struct dyn_ftrace *rec;
4820 unsigned long count;
4823 unsigned long flags = 0; /* Shut up gcc */
4826 count = end - start;
4831 sort(start, count, sizeof(*start),
4832 ftrace_cmp_ips, NULL);
4834 start_pg = ftrace_allocate_pages(count);
4838 mutex_lock(&ftrace_lock);
4841 * Core and each module needs their own pages, as
4842 * modules will free them when they are removed.
4843 * Force a new page to be allocated for modules.
4846 WARN_ON(ftrace_pages || ftrace_pages_start);
4847 /* First initialization */
4848 ftrace_pages = ftrace_pages_start = start_pg;
4853 if (WARN_ON(ftrace_pages->next)) {
4854 /* Hmm, we have free pages? */
4855 while (ftrace_pages->next)
4856 ftrace_pages = ftrace_pages->next;
4859 ftrace_pages->next = start_pg;
4865 addr = ftrace_call_adjust(*p++);
4867 * Some architecture linkers will pad between
4868 * the different mcount_loc sections of different
4869 * object files to satisfy alignments.
4870 * Skip any NULL pointers.
4875 if (pg->index == pg->size) {
4876 /* We should have allocated enough */
4877 if (WARN_ON(!pg->next))
4882 rec = &pg->records[pg->index++];
4886 /* We should have used all pages */
4889 /* Assign the last page to ftrace_pages */
4893 * We only need to disable interrupts on start up
4894 * because we are modifying code that an interrupt
4895 * may execute, and the modification is not atomic.
4896 * But for modules, nothing runs the code we modify
4897 * until we are finished with it, and there's no
4898 * reason to cause large interrupt latencies while we do it.
4901 local_irq_save(flags);
4902 ftrace_update_code(mod, start_pg);
4904 local_irq_restore(flags);
4907 mutex_unlock(&ftrace_lock);
4912 #ifdef CONFIG_MODULES
4914 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4916 static int referenced_filters(struct dyn_ftrace *rec)
4918 struct ftrace_ops *ops;
4921 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
4922 if (ops_references_rec(ops, rec))
4929 void ftrace_release_mod(struct module *mod)
4931 struct dyn_ftrace *rec;
4932 struct ftrace_page **last_pg;
4933 struct ftrace_page *pg;
4936 mutex_lock(&ftrace_lock);
4938 if (ftrace_disabled)
4942 * Each module has its own ftrace_pages, remove
4943 * them from the list.
4945 last_pg = &ftrace_pages_start;
4946 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4947 rec = &pg->records[0];
4948 if (within_module_core(rec->ip, mod)) {
4950 * As core pages are first, the first
4951 * page should never be a module page.
4953 if (WARN_ON(pg == ftrace_pages_start))
4956 /* Check if we are deleting the last page */
4957 if (pg == ftrace_pages)
4958 ftrace_pages = next_to_ftrace_page(last_pg);
4960 *last_pg = pg->next;
4961 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4962 free_pages((unsigned long)pg->records, order);
4965 last_pg = &pg->next;
4968 mutex_unlock(&ftrace_lock);
4971 void ftrace_module_enable(struct module *mod)
4973 struct dyn_ftrace *rec;
4974 struct ftrace_page *pg;
4976 mutex_lock(&ftrace_lock);
4978 if (ftrace_disabled)
4982 * If the tracing is enabled, go ahead and enable the record.
4984 * The reason not to enable the record immediatelly is the
4985 * inherent check of ftrace_make_nop/ftrace_make_call for
4986 * correct previous instructions. Making first the NOP
4987 * conversion puts the module to the correct state, thus
4988 * passing the ftrace_make_call check.
4990 * We also delay this to after the module code already set the
4991 * text to read-only, as we now need to set it back to read-write
4992 * so that we can modify the text.
4994 if (ftrace_start_up)
4995 ftrace_arch_code_modify_prepare();
4997 do_for_each_ftrace_rec(pg, rec) {
5000 * do_for_each_ftrace_rec() is a double loop.
5001 * module text shares the pg. If a record is
5002 * not part of this module, then skip this pg,
5003 * which the "break" will do.
5005 if (!within_module_core(rec->ip, mod))
5011 * When adding a module, we need to check if tracers are
5012 * currently enabled and if they are, and can trace this record,
5013 * we need to enable the module functions as well as update the
5014 * reference counts for those function records.
5016 if (ftrace_start_up)
5017 cnt += referenced_filters(rec);
5019 /* This clears FTRACE_FL_DISABLED */
5022 if (ftrace_start_up && cnt) {
5023 int failed = __ftrace_replace_code(rec, 1);
5025 ftrace_bug(failed, rec);
5030 } while_for_each_ftrace_rec();
5033 if (ftrace_start_up)
5034 ftrace_arch_code_modify_post_process();
5037 mutex_unlock(&ftrace_lock);
5040 void ftrace_module_init(struct module *mod)
5042 if (ftrace_disabled || !mod->num_ftrace_callsites)
5045 ftrace_process_locs(mod, mod->ftrace_callsites,
5046 mod->ftrace_callsites + mod->num_ftrace_callsites);
5048 #endif /* CONFIG_MODULES */
5050 void __init ftrace_init(void)
5052 extern unsigned long __start_mcount_loc[];
5053 extern unsigned long __stop_mcount_loc[];
5054 unsigned long count, flags;
5057 local_irq_save(flags);
5058 ret = ftrace_dyn_arch_init();
5059 local_irq_restore(flags);
5063 count = __stop_mcount_loc - __start_mcount_loc;
5065 pr_info("ftrace: No functions to be traced?\n");
5069 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5070 count, count / ENTRIES_PER_PAGE + 1);
5072 last_ftrace_enabled = ftrace_enabled = 1;
5074 ret = ftrace_process_locs(NULL,
5078 set_ftrace_early_filters();
5082 ftrace_disabled = 1;
5085 /* Do nothing if arch does not support this */
5086 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5090 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5094 * Currently there's no safe way to free a trampoline when the kernel
5095 * is configured with PREEMPT. That is because a task could be preempted
5096 * when it jumped to the trampoline, it may be preempted for a long time
5097 * depending on the system load, and currently there's no way to know
5098 * when it will be off the trampoline. If the trampoline is freed
5099 * too early, when the task runs again, it will be executing on freed
5102 #ifdef CONFIG_PREEMPT
5103 /* Currently, only non dynamic ops can have a trampoline */
5104 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5108 arch_ftrace_update_trampoline(ops);
5113 static struct ftrace_ops global_ops = {
5114 .func = ftrace_stub,
5115 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5116 FTRACE_OPS_FL_INITIALIZED |
5120 static int __init ftrace_nodyn_init(void)
5125 core_initcall(ftrace_nodyn_init);
5127 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5128 static inline void ftrace_startup_enable(int command) { }
5129 static inline void ftrace_startup_all(int command) { }
5130 /* Keep as macros so we do not need to define the commands */
5131 # define ftrace_startup(ops, command) \
5133 int ___ret = __register_ftrace_function(ops); \
5135 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5138 # define ftrace_shutdown(ops, command) \
5140 int ___ret = __unregister_ftrace_function(ops); \
5142 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5146 # define ftrace_startup_sysctl() do { } while (0)
5147 # define ftrace_shutdown_sysctl() do { } while (0)
5150 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5155 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5159 #endif /* CONFIG_DYNAMIC_FTRACE */
5161 __init void ftrace_init_global_array_ops(struct trace_array *tr)
5163 tr->ops = &global_ops;
5164 tr->ops->private = tr;
5167 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5169 /* If we filter on pids, update to use the pid function */
5170 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5171 if (WARN_ON(tr->ops->func != ftrace_stub))
5172 printk("ftrace ops had %pS for function\n",
5175 tr->ops->func = func;
5176 tr->ops->private = tr;
5179 void ftrace_reset_array_ops(struct trace_array *tr)
5181 tr->ops->func = ftrace_stub;
5185 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5186 struct ftrace_ops *ignored, struct pt_regs *regs)
5188 struct ftrace_ops *op;
5191 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5196 * Some of the ops may be dynamically allocated,
5197 * they must be freed after a synchronize_sched().
5199 preempt_disable_notrace();
5201 do_for_each_ftrace_op(op, ftrace_ops_list) {
5203 * Check the following for each ops before calling their func:
5204 * if RCU flag is set, then rcu_is_watching() must be true
5205 * if PER_CPU is set, then ftrace_function_local_disable()
5207 * Otherwise test if the ip matches the ops filter
5209 * If any of the above fails then the op->func() is not executed.
5211 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5212 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5213 !ftrace_function_local_disabled(op)) &&
5214 ftrace_ops_test(op, ip, regs)) {
5216 if (FTRACE_WARN_ON(!op->func)) {
5217 pr_warn("op=%p %pS\n", op, op);
5220 op->func(ip, parent_ip, op, regs);
5222 } while_for_each_ftrace_op(op);
5224 preempt_enable_notrace();
5225 trace_clear_recursion(bit);
5229 * Some archs only support passing ip and parent_ip. Even though
5230 * the list function ignores the op parameter, we do not want any
5231 * C side effects, where a function is called without the caller
5232 * sending a third parameter.
5233 * Archs are to support both the regs and ftrace_ops at the same time.
5234 * If they support ftrace_ops, it is assumed they support regs.
5235 * If call backs want to use regs, they must either check for regs
5236 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5237 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5238 * An architecture can pass partial regs with ftrace_ops and still
5239 * set the ARCH_SUPPORTS_FTRACE_OPS.
5241 #if ARCH_SUPPORTS_FTRACE_OPS
5242 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5243 struct ftrace_ops *op, struct pt_regs *regs)
5245 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5248 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5250 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5255 * If there's only one function registered but it does not support
5256 * recursion, needs RCU protection and/or requires per cpu handling, then
5257 * this function will be called by the mcount trampoline.
5259 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
5260 struct ftrace_ops *op, struct pt_regs *regs)
5264 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
5267 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5271 preempt_disable_notrace();
5273 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5274 !ftrace_function_local_disabled(op)) {
5275 op->func(ip, parent_ip, op, regs);
5278 preempt_enable_notrace();
5279 trace_clear_recursion(bit);
5283 * ftrace_ops_get_func - get the function a trampoline should call
5284 * @ops: the ops to get the function for
5286 * Normally the mcount trampoline will call the ops->func, but there
5287 * are times that it should not. For example, if the ops does not
5288 * have its own recursion protection, then it should call the
5289 * ftrace_ops_recurs_func() instead.
5291 * Returns the function that the trampoline should call for @ops.
5293 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5296 * If the function does not handle recursion, needs to be RCU safe,
5297 * or does per cpu logic, then we need to call the assist handler.
5299 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
5300 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
5301 return ftrace_ops_assist_func;
5306 static void clear_ftrace_swapper(void)
5308 struct task_struct *p;
5312 for_each_online_cpu(cpu) {
5314 clear_tsk_trace_trace(p);
5319 static void set_ftrace_swapper(void)
5321 struct task_struct *p;
5325 for_each_online_cpu(cpu) {
5327 set_tsk_trace_trace(p);
5332 static void clear_ftrace_pid(struct pid *pid)
5334 struct task_struct *p;
5337 do_each_pid_task(pid, PIDTYPE_PID, p) {
5338 clear_tsk_trace_trace(p);
5339 } while_each_pid_task(pid, PIDTYPE_PID, p);
5345 static void set_ftrace_pid(struct pid *pid)
5347 struct task_struct *p;
5350 do_each_pid_task(pid, PIDTYPE_PID, p) {
5351 set_tsk_trace_trace(p);
5352 } while_each_pid_task(pid, PIDTYPE_PID, p);
5356 static void clear_ftrace_pid_task(struct pid *pid)
5358 if (pid == ftrace_swapper_pid)
5359 clear_ftrace_swapper();
5361 clear_ftrace_pid(pid);
5364 static void set_ftrace_pid_task(struct pid *pid)
5366 if (pid == ftrace_swapper_pid)
5367 set_ftrace_swapper();
5369 set_ftrace_pid(pid);
5372 static int ftrace_pid_add(int p)
5375 struct ftrace_pid *fpid;
5378 mutex_lock(&ftrace_lock);
5381 pid = ftrace_swapper_pid;
5383 pid = find_get_pid(p);
5390 list_for_each_entry(fpid, &ftrace_pids, list)
5391 if (fpid->pid == pid)
5396 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
5400 list_add(&fpid->list, &ftrace_pids);
5403 set_ftrace_pid_task(pid);
5405 ftrace_update_pid_func();
5407 ftrace_startup_all(0);
5409 mutex_unlock(&ftrace_lock);
5413 if (pid != ftrace_swapper_pid)
5417 mutex_unlock(&ftrace_lock);
5421 static void ftrace_pid_reset(void)
5423 struct ftrace_pid *fpid, *safe;
5425 mutex_lock(&ftrace_lock);
5426 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
5427 struct pid *pid = fpid->pid;
5429 clear_ftrace_pid_task(pid);
5431 list_del(&fpid->list);
5435 ftrace_update_pid_func();
5436 ftrace_startup_all(0);
5438 mutex_unlock(&ftrace_lock);
5441 static void *fpid_start(struct seq_file *m, loff_t *pos)
5443 mutex_lock(&ftrace_lock);
5445 if (!ftrace_pids_enabled() && (!*pos))
5448 return seq_list_start(&ftrace_pids, *pos);
5451 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5456 return seq_list_next(v, &ftrace_pids, pos);
5459 static void fpid_stop(struct seq_file *m, void *p)
5461 mutex_unlock(&ftrace_lock);
5464 static int fpid_show(struct seq_file *m, void *v)
5466 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
5468 if (v == (void *)1) {
5469 seq_puts(m, "no pid\n");
5473 if (fpid->pid == ftrace_swapper_pid)
5474 seq_puts(m, "swapper tasks\n");
5476 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
5481 static const struct seq_operations ftrace_pid_sops = {
5482 .start = fpid_start,
5489 ftrace_pid_open(struct inode *inode, struct file *file)
5493 if ((file->f_mode & FMODE_WRITE) &&
5494 (file->f_flags & O_TRUNC))
5497 if (file->f_mode & FMODE_READ)
5498 ret = seq_open(file, &ftrace_pid_sops);
5504 ftrace_pid_write(struct file *filp, const char __user *ubuf,
5505 size_t cnt, loff_t *ppos)
5511 if (cnt >= sizeof(buf))
5514 if (copy_from_user(&buf, ubuf, cnt))
5520 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
5521 * to clean the filter quietly.
5523 tmp = strstrip(buf);
5524 if (strlen(tmp) == 0)
5527 ret = kstrtol(tmp, 10, &val);
5531 ret = ftrace_pid_add(val);
5533 return ret ? ret : cnt;
5537 ftrace_pid_release(struct inode *inode, struct file *file)
5539 if (file->f_mode & FMODE_READ)
5540 seq_release(inode, file);
5545 static const struct file_operations ftrace_pid_fops = {
5546 .open = ftrace_pid_open,
5547 .write = ftrace_pid_write,
5549 .llseek = tracing_lseek,
5550 .release = ftrace_pid_release,
5553 static __init int ftrace_init_tracefs(void)
5555 struct dentry *d_tracer;
5557 d_tracer = tracing_init_dentry();
5558 if (IS_ERR(d_tracer))
5561 ftrace_init_dyn_tracefs(d_tracer);
5563 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5564 NULL, &ftrace_pid_fops);
5566 ftrace_profile_tracefs(d_tracer);
5570 fs_initcall(ftrace_init_tracefs);
5573 * ftrace_kill - kill ftrace
5575 * This function should be used by panic code. It stops ftrace
5576 * but in a not so nice way. If you need to simply kill ftrace
5577 * from a non-atomic section, use ftrace_kill.
5579 void ftrace_kill(void)
5581 ftrace_disabled = 1;
5583 clear_ftrace_function();
5587 * Test if ftrace is dead or not.
5589 int ftrace_is_dead(void)
5591 return ftrace_disabled;
5595 * register_ftrace_function - register a function for profiling
5596 * @ops - ops structure that holds the function for profiling.
5598 * Register a function to be called by all functions in the
5601 * Note: @ops->func and all the functions it calls must be labeled
5602 * with "notrace", otherwise it will go into a
5605 int register_ftrace_function(struct ftrace_ops *ops)
5609 ftrace_ops_init(ops);
5611 mutex_lock(&ftrace_lock);
5613 ret = ftrace_startup(ops, 0);
5615 mutex_unlock(&ftrace_lock);
5619 EXPORT_SYMBOL_GPL(register_ftrace_function);
5622 * unregister_ftrace_function - unregister a function for profiling.
5623 * @ops - ops structure that holds the function to unregister
5625 * Unregister a function that was added to be called by ftrace profiling.
5627 int unregister_ftrace_function(struct ftrace_ops *ops)
5631 mutex_lock(&ftrace_lock);
5632 ret = ftrace_shutdown(ops, 0);
5633 mutex_unlock(&ftrace_lock);
5637 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5640 ftrace_enable_sysctl(struct ctl_table *table, int write,
5641 void __user *buffer, size_t *lenp,
5646 mutex_lock(&ftrace_lock);
5648 if (unlikely(ftrace_disabled))
5651 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5653 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5656 last_ftrace_enabled = !!ftrace_enabled;
5658 if (ftrace_enabled) {
5660 /* we are starting ftrace again */
5661 if (ftrace_ops_list != &ftrace_list_end)
5662 update_ftrace_function();
5664 ftrace_startup_sysctl();
5667 /* stopping ftrace calls (just send to ftrace_stub) */
5668 ftrace_trace_function = ftrace_stub;
5670 ftrace_shutdown_sysctl();
5674 mutex_unlock(&ftrace_lock);
5678 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5680 static struct ftrace_ops graph_ops = {
5681 .func = ftrace_stub,
5682 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5683 FTRACE_OPS_FL_INITIALIZED |
5686 #ifdef FTRACE_GRAPH_TRAMP_ADDR
5687 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5688 /* trampoline_size is only needed for dynamically allocated tramps */
5690 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5693 void ftrace_graph_sleep_time_control(bool enable)
5695 fgraph_sleep_time = enable;
5698 void ftrace_graph_graph_time_control(bool enable)
5700 fgraph_graph_time = enable;
5703 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5708 /* The callbacks that hook a function */
5709 trace_func_graph_ret_t ftrace_graph_return =
5710 (trace_func_graph_ret_t)ftrace_stub;
5711 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5712 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5714 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5715 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5719 unsigned long flags;
5720 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5721 struct task_struct *g, *t;
5723 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5724 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5725 * sizeof(struct ftrace_ret_stack),
5727 if (!ret_stack_list[i]) {
5735 read_lock_irqsave(&tasklist_lock, flags);
5736 do_each_thread(g, t) {
5742 if (t->ret_stack == NULL) {
5743 atomic_set(&t->tracing_graph_pause, 0);
5744 atomic_set(&t->trace_overrun, 0);
5745 t->curr_ret_stack = -1;
5746 /* Make sure the tasks see the -1 first: */
5748 t->ret_stack = ret_stack_list[start++];
5750 } while_each_thread(g, t);
5753 read_unlock_irqrestore(&tasklist_lock, flags);
5755 for (i = start; i < end; i++)
5756 kfree(ret_stack_list[i]);
5761 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5762 struct task_struct *prev, struct task_struct *next)
5764 unsigned long long timestamp;
5768 * Does the user want to count the time a function was asleep.
5769 * If so, do not update the time stamps.
5771 if (fgraph_sleep_time)
5774 timestamp = trace_clock_local();
5776 prev->ftrace_timestamp = timestamp;
5778 /* only process tasks that we timestamped */
5779 if (!next->ftrace_timestamp)
5783 * Update all the counters in next to make up for the
5784 * time next was sleeping.
5786 timestamp -= next->ftrace_timestamp;
5788 for (index = next->curr_ret_stack; index >= 0; index--)
5789 next->ret_stack[index].calltime += timestamp;
5792 /* Allocate a return stack for each task */
5793 static int start_graph_tracing(void)
5795 struct ftrace_ret_stack **ret_stack_list;
5798 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5799 sizeof(struct ftrace_ret_stack *),
5802 if (!ret_stack_list)
5805 /* The cpu_boot init_task->ret_stack will never be freed */
5806 for_each_online_cpu(cpu) {
5807 if (!idle_task(cpu)->ret_stack)
5808 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5812 ret = alloc_retstack_tasklist(ret_stack_list);
5813 } while (ret == -EAGAIN);
5816 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5818 pr_info("ftrace_graph: Couldn't activate tracepoint"
5819 " probe to kernel_sched_switch\n");
5822 kfree(ret_stack_list);
5827 * Hibernation protection.
5828 * The state of the current task is too much unstable during
5829 * suspend/restore to disk. We want to protect against that.
5832 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5836 case PM_HIBERNATION_PREPARE:
5837 pause_graph_tracing();
5840 case PM_POST_HIBERNATION:
5841 unpause_graph_tracing();
5847 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5849 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5851 return __ftrace_graph_entry(trace);
5855 * The function graph tracer should only trace the functions defined
5856 * by set_ftrace_filter and set_ftrace_notrace. If another function
5857 * tracer ops is registered, the graph tracer requires testing the
5858 * function against the global ops, and not just trace any function
5859 * that any ftrace_ops registered.
5861 static void update_function_graph_func(void)
5863 struct ftrace_ops *op;
5864 bool do_test = false;
5867 * The graph and global ops share the same set of functions
5868 * to test. If any other ops is on the list, then
5869 * the graph tracing needs to test if its the function
5872 do_for_each_ftrace_op(op, ftrace_ops_list) {
5873 if (op != &global_ops && op != &graph_ops &&
5874 op != &ftrace_list_end) {
5876 /* in double loop, break out with goto */
5879 } while_for_each_ftrace_op(op);
5882 ftrace_graph_entry = ftrace_graph_entry_test;
5884 ftrace_graph_entry = __ftrace_graph_entry;
5887 static struct notifier_block ftrace_suspend_notifier = {
5888 .notifier_call = ftrace_suspend_notifier_call,
5891 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5892 trace_func_graph_ent_t entryfunc)
5896 mutex_lock(&ftrace_lock);
5898 /* we currently allow only one tracer registered at a time */
5899 if (ftrace_graph_active) {
5904 register_pm_notifier(&ftrace_suspend_notifier);
5906 ftrace_graph_active++;
5907 ret = start_graph_tracing();
5909 ftrace_graph_active--;
5913 ftrace_graph_return = retfunc;
5916 * Update the indirect function to the entryfunc, and the
5917 * function that gets called to the entry_test first. Then
5918 * call the update fgraph entry function to determine if
5919 * the entryfunc should be called directly or not.
5921 __ftrace_graph_entry = entryfunc;
5922 ftrace_graph_entry = ftrace_graph_entry_test;
5923 update_function_graph_func();
5925 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5927 mutex_unlock(&ftrace_lock);
5931 void unregister_ftrace_graph(void)
5933 mutex_lock(&ftrace_lock);
5935 if (unlikely(!ftrace_graph_active))
5938 ftrace_graph_active--;
5939 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5940 ftrace_graph_entry = ftrace_graph_entry_stub;
5941 __ftrace_graph_entry = ftrace_graph_entry_stub;
5942 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5943 unregister_pm_notifier(&ftrace_suspend_notifier);
5944 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5946 #ifdef CONFIG_DYNAMIC_FTRACE
5948 * Function graph does not allocate the trampoline, but
5949 * other global_ops do. We need to reset the ALLOC_TRAMP flag
5952 global_ops.trampoline = save_global_trampoline;
5953 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
5954 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
5958 mutex_unlock(&ftrace_lock);
5961 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5964 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5966 atomic_set(&t->tracing_graph_pause, 0);
5967 atomic_set(&t->trace_overrun, 0);
5968 t->ftrace_timestamp = 0;
5969 /* make curr_ret_stack visible before we add the ret_stack */
5971 t->ret_stack = ret_stack;
5975 * Allocate a return stack for the idle task. May be the first
5976 * time through, or it may be done by CPU hotplug online.
5978 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5980 t->curr_ret_stack = -1;
5982 * The idle task has no parent, it either has its own
5983 * stack or no stack at all.
5986 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5988 if (ftrace_graph_active) {
5989 struct ftrace_ret_stack *ret_stack;
5991 ret_stack = per_cpu(idle_ret_stack, cpu);
5993 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5994 * sizeof(struct ftrace_ret_stack),
5998 per_cpu(idle_ret_stack, cpu) = ret_stack;
6000 graph_init_task(t, ret_stack);
6004 /* Allocate a return stack for newly created task */
6005 void ftrace_graph_init_task(struct task_struct *t)
6007 /* Make sure we do not use the parent ret_stack */
6008 t->ret_stack = NULL;
6009 t->curr_ret_stack = -1;
6011 if (ftrace_graph_active) {
6012 struct ftrace_ret_stack *ret_stack;
6014 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6015 * sizeof(struct ftrace_ret_stack),
6019 graph_init_task(t, ret_stack);
6023 void ftrace_graph_exit_task(struct task_struct *t)
6025 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6027 t->ret_stack = NULL;
6028 /* NULL must become visible to IRQs before we free it: */