1 // SPDX-License-Identifier: GPL-2.0
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code in the latency_tracer, that is:
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
17 #include <linux/stop_machine.h>
18 #include <linux/clocksource.h>
19 #include <linux/sched/task.h>
20 #include <linux/kallsyms.h>
21 #include <linux/security.h>
22 #include <linux/seq_file.h>
23 #include <linux/tracefs.h>
24 #include <linux/hardirq.h>
25 #include <linux/kthread.h>
26 #include <linux/uaccess.h>
27 #include <linux/bsearch.h>
28 #include <linux/module.h>
29 #include <linux/ftrace.h>
30 #include <linux/sysctl.h>
31 #include <linux/slab.h>
32 #include <linux/ctype.h>
33 #include <linux/sort.h>
34 #include <linux/list.h>
35 #include <linux/hash.h>
36 #include <linux/rcupdate.h>
37 #include <linux/kprobes.h>
39 #include <trace/events/sched.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
44 #include "ftrace_internal.h"
45 #include "trace_output.h"
46 #include "trace_stat.h"
48 #define FTRACE_WARN_ON(cond) \
56 #define FTRACE_WARN_ON_ONCE(cond) \
59 if (WARN_ON_ONCE(___r)) \
64 /* hash bits for specific function selection */
65 #define FTRACE_HASH_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
77 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
78 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
81 struct ftrace_ops ftrace_list_end __read_mostly = {
83 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
84 INIT_OPS_HASH(ftrace_list_end)
87 /* ftrace_enabled is a method to turn ftrace on or off */
88 int ftrace_enabled __read_mostly;
89 static int last_ftrace_enabled;
91 /* Current function tracing op */
92 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
93 /* What to set function_trace_op to */
94 static struct ftrace_ops *set_function_trace_op;
96 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
98 struct trace_array *tr;
100 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
105 return tr->function_pids != NULL || tr->function_no_pids != NULL;
108 static void ftrace_update_trampoline(struct ftrace_ops *ops);
111 * ftrace_disabled is set when an anomaly is discovered.
112 * ftrace_disabled is much stronger than ftrace_enabled.
114 static int ftrace_disabled __read_mostly;
116 DEFINE_MUTEX(ftrace_lock);
118 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
119 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
120 struct ftrace_ops global_ops;
122 #if ARCH_SUPPORTS_FTRACE_OPS
123 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
124 struct ftrace_ops *op, struct pt_regs *regs);
126 /* See comment below, where ftrace_ops_list_func is defined */
127 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
128 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 static inline void ftrace_ops_init(struct ftrace_ops *ops)
133 #ifdef CONFIG_DYNAMIC_FTRACE
134 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
135 mutex_init(&ops->local_hash.regex_lock);
136 ops->func_hash = &ops->local_hash;
137 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
142 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
143 struct ftrace_ops *op, struct pt_regs *regs)
145 struct trace_array *tr = op->private;
149 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
150 if (pid == FTRACE_PID_IGNORE)
152 if (pid != FTRACE_PID_TRACE &&
157 op->saved_func(ip, parent_ip, op, regs);
160 static void ftrace_sync_ipi(void *data)
162 /* Probably not needed, but do it anyway */
166 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
169 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
170 * then it needs to call the list anyway.
172 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
173 FTRACE_FORCE_LIST_FUNC)
174 return ftrace_ops_list_func;
176 return ftrace_ops_get_func(ops);
179 static void update_ftrace_function(void)
184 * Prepare the ftrace_ops that the arch callback will use.
185 * If there's only one ftrace_ops registered, the ftrace_ops_list
186 * will point to the ops we want.
188 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
189 lockdep_is_held(&ftrace_lock));
191 /* If there's no ftrace_ops registered, just call the stub function */
192 if (set_function_trace_op == &ftrace_list_end) {
196 * If we are at the end of the list and this ops is
197 * recursion safe and not dynamic and the arch supports passing ops,
198 * then have the mcount trampoline call the function directly.
200 } else if (rcu_dereference_protected(ftrace_ops_list->next,
201 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
202 func = ftrace_ops_get_list_func(ftrace_ops_list);
205 /* Just use the default ftrace_ops */
206 set_function_trace_op = &ftrace_list_end;
207 func = ftrace_ops_list_func;
210 update_function_graph_func();
212 /* If there's no change, then do nothing more here */
213 if (ftrace_trace_function == func)
217 * If we are using the list function, it doesn't care
218 * about the function_trace_ops.
220 if (func == ftrace_ops_list_func) {
221 ftrace_trace_function = func;
223 * Don't even bother setting function_trace_ops,
224 * it would be racy to do so anyway.
229 #ifndef CONFIG_DYNAMIC_FTRACE
231 * For static tracing, we need to be a bit more careful.
232 * The function change takes affect immediately. Thus,
233 * we need to coordinate the setting of the function_trace_ops
234 * with the setting of the ftrace_trace_function.
236 * Set the function to the list ops, which will call the
237 * function we want, albeit indirectly, but it handles the
238 * ftrace_ops and doesn't depend on function_trace_op.
240 ftrace_trace_function = ftrace_ops_list_func;
242 * Make sure all CPUs see this. Yes this is slow, but static
243 * tracing is slow and nasty to have enabled.
245 synchronize_rcu_tasks_rude();
246 /* Now all cpus are using the list ops. */
247 function_trace_op = set_function_trace_op;
248 /* Make sure the function_trace_op is visible on all CPUs */
250 /* Nasty way to force a rmb on all cpus */
251 smp_call_function(ftrace_sync_ipi, NULL, 1);
252 /* OK, we are all set to update the ftrace_trace_function now! */
253 #endif /* !CONFIG_DYNAMIC_FTRACE */
255 ftrace_trace_function = func;
258 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
259 struct ftrace_ops *ops)
261 rcu_assign_pointer(ops->next, *list);
264 * We are entering ops into the list but another
265 * CPU might be walking that list. We need to make sure
266 * the ops->next pointer is valid before another CPU sees
267 * the ops pointer included into the list.
269 rcu_assign_pointer(*list, ops);
272 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
273 struct ftrace_ops *ops)
275 struct ftrace_ops **p;
278 * If we are removing the last function, then simply point
279 * to the ftrace_stub.
281 if (rcu_dereference_protected(*list,
282 lockdep_is_held(&ftrace_lock)) == ops &&
283 rcu_dereference_protected(ops->next,
284 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
285 *list = &ftrace_list_end;
289 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
300 static void ftrace_update_trampoline(struct ftrace_ops *ops);
302 int __register_ftrace_function(struct ftrace_ops *ops)
304 if (ops->flags & FTRACE_OPS_FL_DELETED)
307 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
310 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
312 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
313 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
314 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
316 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
317 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
320 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
321 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
323 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
326 if (!core_kernel_data((unsigned long)ops))
327 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
329 add_ftrace_ops(&ftrace_ops_list, ops);
331 /* Always save the function, and reset at unregistering */
332 ops->saved_func = ops->func;
334 if (ftrace_pids_enabled(ops))
335 ops->func = ftrace_pid_func;
337 ftrace_update_trampoline(ops);
340 update_ftrace_function();
345 int __unregister_ftrace_function(struct ftrace_ops *ops)
349 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
352 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
358 update_ftrace_function();
360 ops->func = ops->saved_func;
365 static void ftrace_update_pid_func(void)
367 struct ftrace_ops *op;
369 /* Only do something if we are tracing something */
370 if (ftrace_trace_function == ftrace_stub)
373 do_for_each_ftrace_op(op, ftrace_ops_list) {
374 if (op->flags & FTRACE_OPS_FL_PID) {
375 op->func = ftrace_pids_enabled(op) ?
376 ftrace_pid_func : op->saved_func;
377 ftrace_update_trampoline(op);
379 } while_for_each_ftrace_op(op);
381 update_ftrace_function();
384 #ifdef CONFIG_FUNCTION_PROFILER
385 struct ftrace_profile {
386 struct hlist_node node;
388 unsigned long counter;
389 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
390 unsigned long long time;
391 unsigned long long time_squared;
395 struct ftrace_profile_page {
396 struct ftrace_profile_page *next;
398 struct ftrace_profile records[];
401 struct ftrace_profile_stat {
403 struct hlist_head *hash;
404 struct ftrace_profile_page *pages;
405 struct ftrace_profile_page *start;
406 struct tracer_stat stat;
409 #define PROFILE_RECORDS_SIZE \
410 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
412 #define PROFILES_PER_PAGE \
413 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
415 static int ftrace_profile_enabled __read_mostly;
417 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
418 static DEFINE_MUTEX(ftrace_profile_lock);
420 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
422 #define FTRACE_PROFILE_HASH_BITS 10
423 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
426 function_stat_next(void *v, int idx)
428 struct ftrace_profile *rec = v;
429 struct ftrace_profile_page *pg;
431 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
437 if ((void *)rec >= (void *)&pg->records[pg->index]) {
441 rec = &pg->records[0];
449 static void *function_stat_start(struct tracer_stat *trace)
451 struct ftrace_profile_stat *stat =
452 container_of(trace, struct ftrace_profile_stat, stat);
454 if (!stat || !stat->start)
457 return function_stat_next(&stat->start->records[0], 0);
460 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
461 /* function graph compares on total time */
462 static int function_stat_cmp(const void *p1, const void *p2)
464 const struct ftrace_profile *a = p1;
465 const struct ftrace_profile *b = p2;
467 if (a->time < b->time)
469 if (a->time > b->time)
475 /* not function graph compares against hits */
476 static int function_stat_cmp(const void *p1, const void *p2)
478 const struct ftrace_profile *a = p1;
479 const struct ftrace_profile *b = p2;
481 if (a->counter < b->counter)
483 if (a->counter > b->counter)
490 static int function_stat_headers(struct seq_file *m)
492 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
493 seq_puts(m, " Function "
496 "--- ---- --- ---\n");
498 seq_puts(m, " Function Hit\n"
504 static int function_stat_show(struct seq_file *m, void *v)
506 struct ftrace_profile *rec = v;
507 char str[KSYM_SYMBOL_LEN];
509 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
510 static struct trace_seq s;
511 unsigned long long avg;
512 unsigned long long stddev;
514 mutex_lock(&ftrace_profile_lock);
516 /* we raced with function_profile_reset() */
517 if (unlikely(rec->counter == 0)) {
522 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
523 avg = div64_ul(rec->time, rec->counter);
524 if (tracing_thresh && (avg < tracing_thresh))
528 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
529 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
531 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
534 /* Sample standard deviation (s^2) */
535 if (rec->counter <= 1)
539 * Apply Welford's method:
540 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
542 stddev = rec->counter * rec->time_squared -
543 rec->time * rec->time;
546 * Divide only 1000 for ns^2 -> us^2 conversion.
547 * trace_print_graph_duration will divide 1000 again.
549 stddev = div64_ul(stddev,
550 rec->counter * (rec->counter - 1) * 1000);
554 trace_print_graph_duration(rec->time, &s);
555 trace_seq_puts(&s, " ");
556 trace_print_graph_duration(avg, &s);
557 trace_seq_puts(&s, " ");
558 trace_print_graph_duration(stddev, &s);
559 trace_print_seq(m, &s);
563 mutex_unlock(&ftrace_profile_lock);
568 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
570 struct ftrace_profile_page *pg;
572 pg = stat->pages = stat->start;
575 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
580 memset(stat->hash, 0,
581 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
584 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
586 struct ftrace_profile_page *pg;
591 /* If we already allocated, do nothing */
595 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
599 #ifdef CONFIG_DYNAMIC_FTRACE
600 functions = ftrace_update_tot_cnt;
603 * We do not know the number of functions that exist because
604 * dynamic tracing is what counts them. With past experience
605 * we have around 20K functions. That should be more than enough.
606 * It is highly unlikely we will execute every function in
612 pg = stat->start = stat->pages;
614 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
616 for (i = 1; i < pages; i++) {
617 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
628 unsigned long tmp = (unsigned long)pg;
640 static int ftrace_profile_init_cpu(int cpu)
642 struct ftrace_profile_stat *stat;
645 stat = &per_cpu(ftrace_profile_stats, cpu);
648 /* If the profile is already created, simply reset it */
649 ftrace_profile_reset(stat);
654 * We are profiling all functions, but usually only a few thousand
655 * functions are hit. We'll make a hash of 1024 items.
657 size = FTRACE_PROFILE_HASH_SIZE;
659 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
664 /* Preallocate the function profiling pages */
665 if (ftrace_profile_pages_init(stat) < 0) {
674 static int ftrace_profile_init(void)
679 for_each_possible_cpu(cpu) {
680 ret = ftrace_profile_init_cpu(cpu);
688 /* interrupts must be disabled */
689 static struct ftrace_profile *
690 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
692 struct ftrace_profile *rec;
693 struct hlist_head *hhd;
696 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
697 hhd = &stat->hash[key];
699 if (hlist_empty(hhd))
702 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
710 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
711 struct ftrace_profile *rec)
715 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
716 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
720 * The memory is already allocated, this simply finds a new record to use.
722 static struct ftrace_profile *
723 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
725 struct ftrace_profile *rec = NULL;
727 /* prevent recursion (from NMIs) */
728 if (atomic_inc_return(&stat->disabled) != 1)
732 * Try to find the function again since an NMI
733 * could have added it
735 rec = ftrace_find_profiled_func(stat, ip);
739 if (stat->pages->index == PROFILES_PER_PAGE) {
740 if (!stat->pages->next)
742 stat->pages = stat->pages->next;
745 rec = &stat->pages->records[stat->pages->index++];
747 ftrace_add_profile(stat, rec);
750 atomic_dec(&stat->disabled);
756 function_profile_call(unsigned long ip, unsigned long parent_ip,
757 struct ftrace_ops *ops, struct pt_regs *regs)
759 struct ftrace_profile_stat *stat;
760 struct ftrace_profile *rec;
763 if (!ftrace_profile_enabled)
766 local_irq_save(flags);
768 stat = this_cpu_ptr(&ftrace_profile_stats);
769 if (!stat->hash || !ftrace_profile_enabled)
772 rec = ftrace_find_profiled_func(stat, ip);
774 rec = ftrace_profile_alloc(stat, ip);
781 local_irq_restore(flags);
784 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
785 static bool fgraph_graph_time = true;
787 void ftrace_graph_graph_time_control(bool enable)
789 fgraph_graph_time = enable;
792 static int profile_graph_entry(struct ftrace_graph_ent *trace)
794 struct ftrace_ret_stack *ret_stack;
796 function_profile_call(trace->func, 0, NULL, NULL);
798 /* If function graph is shutting down, ret_stack can be NULL */
799 if (!current->ret_stack)
802 ret_stack = ftrace_graph_get_ret_stack(current, 0);
804 ret_stack->subtime = 0;
809 static void profile_graph_return(struct ftrace_graph_ret *trace)
811 struct ftrace_ret_stack *ret_stack;
812 struct ftrace_profile_stat *stat;
813 unsigned long long calltime;
814 struct ftrace_profile *rec;
817 local_irq_save(flags);
818 stat = this_cpu_ptr(&ftrace_profile_stats);
819 if (!stat->hash || !ftrace_profile_enabled)
822 /* If the calltime was zero'd ignore it */
823 if (!trace->calltime)
826 calltime = trace->rettime - trace->calltime;
828 if (!fgraph_graph_time) {
830 /* Append this call time to the parent time to subtract */
831 ret_stack = ftrace_graph_get_ret_stack(current, 1);
833 ret_stack->subtime += calltime;
835 ret_stack = ftrace_graph_get_ret_stack(current, 0);
836 if (ret_stack && ret_stack->subtime < calltime)
837 calltime -= ret_stack->subtime;
842 rec = ftrace_find_profiled_func(stat, trace->func);
844 rec->time += calltime;
845 rec->time_squared += calltime * calltime;
849 local_irq_restore(flags);
852 static struct fgraph_ops fprofiler_ops = {
853 .entryfunc = &profile_graph_entry,
854 .retfunc = &profile_graph_return,
857 static int register_ftrace_profiler(void)
859 return register_ftrace_graph(&fprofiler_ops);
862 static void unregister_ftrace_profiler(void)
864 unregister_ftrace_graph(&fprofiler_ops);
867 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
868 .func = function_profile_call,
869 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
870 INIT_OPS_HASH(ftrace_profile_ops)
873 static int register_ftrace_profiler(void)
875 return register_ftrace_function(&ftrace_profile_ops);
878 static void unregister_ftrace_profiler(void)
880 unregister_ftrace_function(&ftrace_profile_ops);
882 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
885 ftrace_profile_write(struct file *filp, const char __user *ubuf,
886 size_t cnt, loff_t *ppos)
891 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
897 mutex_lock(&ftrace_profile_lock);
898 if (ftrace_profile_enabled ^ val) {
900 ret = ftrace_profile_init();
906 ret = register_ftrace_profiler();
911 ftrace_profile_enabled = 1;
913 ftrace_profile_enabled = 0;
915 * unregister_ftrace_profiler calls stop_machine
916 * so this acts like an synchronize_rcu.
918 unregister_ftrace_profiler();
922 mutex_unlock(&ftrace_profile_lock);
930 ftrace_profile_read(struct file *filp, char __user *ubuf,
931 size_t cnt, loff_t *ppos)
933 char buf[64]; /* big enough to hold a number */
936 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
937 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
940 static const struct file_operations ftrace_profile_fops = {
941 .open = tracing_open_generic,
942 .read = ftrace_profile_read,
943 .write = ftrace_profile_write,
944 .llseek = default_llseek,
947 /* used to initialize the real stat files */
948 static struct tracer_stat function_stats __initdata = {
950 .stat_start = function_stat_start,
951 .stat_next = function_stat_next,
952 .stat_cmp = function_stat_cmp,
953 .stat_headers = function_stat_headers,
954 .stat_show = function_stat_show
957 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
959 struct ftrace_profile_stat *stat;
960 struct dentry *entry;
965 for_each_possible_cpu(cpu) {
966 stat = &per_cpu(ftrace_profile_stats, cpu);
968 name = kasprintf(GFP_KERNEL, "function%d", cpu);
971 * The files created are permanent, if something happens
972 * we still do not free memory.
975 "Could not allocate stat file for cpu %d\n",
979 stat->stat = function_stats;
980 stat->stat.name = name;
981 ret = register_stat_tracer(&stat->stat);
984 "Could not register function stat for cpu %d\n",
991 entry = tracefs_create_file("function_profile_enabled", 0644,
992 d_tracer, NULL, &ftrace_profile_fops);
994 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
997 #else /* CONFIG_FUNCTION_PROFILER */
998 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1001 #endif /* CONFIG_FUNCTION_PROFILER */
1003 #ifdef CONFIG_DYNAMIC_FTRACE
1005 static struct ftrace_ops *removed_ops;
1008 * Set when doing a global update, like enabling all recs or disabling them.
1009 * It is not set when just updating a single ftrace_ops.
1011 static bool update_all_ops;
1013 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1014 # error Dynamic ftrace depends on MCOUNT_RECORD
1017 struct ftrace_func_probe {
1018 struct ftrace_probe_ops *probe_ops;
1019 struct ftrace_ops ops;
1020 struct trace_array *tr;
1021 struct list_head list;
1027 * We make these constant because no one should touch them,
1028 * but they are used as the default "empty hash", to avoid allocating
1029 * it all the time. These are in a read only section such that if
1030 * anyone does try to modify it, it will cause an exception.
1032 static const struct hlist_head empty_buckets[1];
1033 static const struct ftrace_hash empty_hash = {
1034 .buckets = (struct hlist_head *)empty_buckets,
1036 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1038 struct ftrace_ops global_ops = {
1039 .func = ftrace_stub,
1040 .local_hash.notrace_hash = EMPTY_HASH,
1041 .local_hash.filter_hash = EMPTY_HASH,
1042 INIT_OPS_HASH(global_ops)
1043 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1044 FTRACE_OPS_FL_INITIALIZED |
1049 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1051 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1053 struct ftrace_ops *op = NULL;
1056 * Some of the ops may be dynamically allocated,
1057 * they are freed after a synchronize_rcu().
1059 preempt_disable_notrace();
1061 do_for_each_ftrace_op(op, ftrace_ops_list) {
1063 * This is to check for dynamically allocated trampolines.
1064 * Trampolines that are in kernel text will have
1065 * core_kernel_text() return true.
1067 if (op->trampoline && op->trampoline_size)
1068 if (addr >= op->trampoline &&
1069 addr < op->trampoline + op->trampoline_size) {
1070 preempt_enable_notrace();
1073 } while_for_each_ftrace_op(op);
1074 preempt_enable_notrace();
1080 * This is used by __kernel_text_address() to return true if the
1081 * address is on a dynamically allocated trampoline that would
1082 * not return true for either core_kernel_text() or
1083 * is_module_text_address().
1085 bool is_ftrace_trampoline(unsigned long addr)
1087 return ftrace_ops_trampoline(addr) != NULL;
1090 struct ftrace_page {
1091 struct ftrace_page *next;
1092 struct dyn_ftrace *records;
1097 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1098 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1100 static struct ftrace_page *ftrace_pages_start;
1101 static struct ftrace_page *ftrace_pages;
1103 static __always_inline unsigned long
1104 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1106 if (hash->size_bits > 0)
1107 return hash_long(ip, hash->size_bits);
1112 /* Only use this function if ftrace_hash_empty() has already been tested */
1113 static __always_inline struct ftrace_func_entry *
1114 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1117 struct ftrace_func_entry *entry;
1118 struct hlist_head *hhd;
1120 key = ftrace_hash_key(hash, ip);
1121 hhd = &hash->buckets[key];
1123 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1124 if (entry->ip == ip)
1131 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1132 * @hash: The hash to look at
1133 * @ip: The instruction pointer to test
1135 * Search a given @hash to see if a given instruction pointer (@ip)
1138 * Returns the entry that holds the @ip if found. NULL otherwise.
1140 struct ftrace_func_entry *
1141 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1143 if (ftrace_hash_empty(hash))
1146 return __ftrace_lookup_ip(hash, ip);
1149 static void __add_hash_entry(struct ftrace_hash *hash,
1150 struct ftrace_func_entry *entry)
1152 struct hlist_head *hhd;
1155 key = ftrace_hash_key(hash, entry->ip);
1156 hhd = &hash->buckets[key];
1157 hlist_add_head(&entry->hlist, hhd);
1161 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1163 struct ftrace_func_entry *entry;
1165 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1170 __add_hash_entry(hash, entry);
1176 free_hash_entry(struct ftrace_hash *hash,
1177 struct ftrace_func_entry *entry)
1179 hlist_del(&entry->hlist);
1185 remove_hash_entry(struct ftrace_hash *hash,
1186 struct ftrace_func_entry *entry)
1188 hlist_del_rcu(&entry->hlist);
1192 static void ftrace_hash_clear(struct ftrace_hash *hash)
1194 struct hlist_head *hhd;
1195 struct hlist_node *tn;
1196 struct ftrace_func_entry *entry;
1197 int size = 1 << hash->size_bits;
1203 for (i = 0; i < size; i++) {
1204 hhd = &hash->buckets[i];
1205 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1206 free_hash_entry(hash, entry);
1208 FTRACE_WARN_ON(hash->count);
1211 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1213 list_del(&ftrace_mod->list);
1214 kfree(ftrace_mod->module);
1215 kfree(ftrace_mod->func);
1219 static void clear_ftrace_mod_list(struct list_head *head)
1221 struct ftrace_mod_load *p, *n;
1223 /* stack tracer isn't supported yet */
1227 mutex_lock(&ftrace_lock);
1228 list_for_each_entry_safe(p, n, head, list)
1230 mutex_unlock(&ftrace_lock);
1233 static void free_ftrace_hash(struct ftrace_hash *hash)
1235 if (!hash || hash == EMPTY_HASH)
1237 ftrace_hash_clear(hash);
1238 kfree(hash->buckets);
1242 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1244 struct ftrace_hash *hash;
1246 hash = container_of(rcu, struct ftrace_hash, rcu);
1247 free_ftrace_hash(hash);
1250 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1252 if (!hash || hash == EMPTY_HASH)
1254 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1257 void ftrace_free_filter(struct ftrace_ops *ops)
1259 ftrace_ops_init(ops);
1260 free_ftrace_hash(ops->func_hash->filter_hash);
1261 free_ftrace_hash(ops->func_hash->notrace_hash);
1264 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1266 struct ftrace_hash *hash;
1269 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1273 size = 1 << size_bits;
1274 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1276 if (!hash->buckets) {
1281 hash->size_bits = size_bits;
1287 static int ftrace_add_mod(struct trace_array *tr,
1288 const char *func, const char *module,
1291 struct ftrace_mod_load *ftrace_mod;
1292 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1294 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1298 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1299 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1300 ftrace_mod->enable = enable;
1302 if (!ftrace_mod->func || !ftrace_mod->module)
1305 list_add(&ftrace_mod->list, mod_head);
1310 free_ftrace_mod(ftrace_mod);
1315 static struct ftrace_hash *
1316 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1318 struct ftrace_func_entry *entry;
1319 struct ftrace_hash *new_hash;
1324 new_hash = alloc_ftrace_hash(size_bits);
1329 new_hash->flags = hash->flags;
1332 if (ftrace_hash_empty(hash))
1335 size = 1 << hash->size_bits;
1336 for (i = 0; i < size; i++) {
1337 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1338 ret = add_hash_entry(new_hash, entry->ip);
1344 FTRACE_WARN_ON(new_hash->count != hash->count);
1349 free_ftrace_hash(new_hash);
1354 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1356 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1358 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1359 struct ftrace_hash *new_hash);
1361 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1363 struct ftrace_func_entry *entry;
1364 struct ftrace_hash *new_hash;
1365 struct hlist_head *hhd;
1366 struct hlist_node *tn;
1371 * Use around half the size (max bit of it), but
1372 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1374 bits = fls(size / 2);
1376 /* Don't allocate too much */
1377 if (bits > FTRACE_HASH_MAX_BITS)
1378 bits = FTRACE_HASH_MAX_BITS;
1380 new_hash = alloc_ftrace_hash(bits);
1384 new_hash->flags = src->flags;
1386 size = 1 << src->size_bits;
1387 for (i = 0; i < size; i++) {
1388 hhd = &src->buckets[i];
1389 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1390 remove_hash_entry(src, entry);
1391 __add_hash_entry(new_hash, entry);
1397 static struct ftrace_hash *
1398 __ftrace_hash_move(struct ftrace_hash *src)
1400 int size = src->count;
1403 * If the new source is empty, just return the empty_hash.
1405 if (ftrace_hash_empty(src))
1408 return dup_hash(src, size);
1412 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1413 struct ftrace_hash **dst, struct ftrace_hash *src)
1415 struct ftrace_hash *new_hash;
1418 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1419 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1422 new_hash = __ftrace_hash_move(src);
1426 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1428 /* IPMODIFY should be updated only when filter_hash updating */
1429 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1431 free_ftrace_hash(new_hash);
1437 * Remove the current set, update the hash and add
1440 ftrace_hash_rec_disable_modify(ops, enable);
1442 rcu_assign_pointer(*dst, new_hash);
1444 ftrace_hash_rec_enable_modify(ops, enable);
1449 static bool hash_contains_ip(unsigned long ip,
1450 struct ftrace_ops_hash *hash)
1453 * The function record is a match if it exists in the filter
1454 * hash and not in the notrace hash. Note, an empty hash is
1455 * considered a match for the filter hash, but an empty
1456 * notrace hash is considered not in the notrace hash.
1458 return (ftrace_hash_empty(hash->filter_hash) ||
1459 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1460 (ftrace_hash_empty(hash->notrace_hash) ||
1461 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1465 * Test the hashes for this ops to see if we want to call
1466 * the ops->func or not.
1468 * It's a match if the ip is in the ops->filter_hash or
1469 * the filter_hash does not exist or is empty,
1471 * the ip is not in the ops->notrace_hash.
1473 * This needs to be called with preemption disabled as
1474 * the hashes are freed with call_rcu().
1477 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1479 struct ftrace_ops_hash hash;
1482 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1484 * There's a small race when adding ops that the ftrace handler
1485 * that wants regs, may be called without them. We can not
1486 * allow that handler to be called if regs is NULL.
1488 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1492 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1493 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1495 if (hash_contains_ip(ip, &hash))
1504 * This is a double for. Do not use 'break' to break out of the loop,
1505 * you must use a goto.
1507 #define do_for_each_ftrace_rec(pg, rec) \
1508 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1510 for (_____i = 0; _____i < pg->index; _____i++) { \
1511 rec = &pg->records[_____i];
1513 #define while_for_each_ftrace_rec() \
1518 static int ftrace_cmp_recs(const void *a, const void *b)
1520 const struct dyn_ftrace *key = a;
1521 const struct dyn_ftrace *rec = b;
1523 if (key->flags < rec->ip)
1525 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1530 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1532 struct ftrace_page *pg;
1533 struct dyn_ftrace *rec = NULL;
1534 struct dyn_ftrace key;
1537 key.flags = end; /* overload flags, as it is unsigned long */
1539 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1540 if (end < pg->records[0].ip ||
1541 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1543 rec = bsearch(&key, pg->records, pg->index,
1544 sizeof(struct dyn_ftrace),
1553 * ftrace_location_range - return the first address of a traced location
1554 * if it touches the given ip range
1555 * @start: start of range to search.
1556 * @end: end of range to search (inclusive). @end points to the last byte
1559 * Returns rec->ip if the related ftrace location is a least partly within
1560 * the given address range. That is, the first address of the instruction
1561 * that is either a NOP or call to the function tracer. It checks the ftrace
1562 * internal tables to determine if the address belongs or not.
1564 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1566 struct dyn_ftrace *rec;
1568 rec = lookup_rec(start, end);
1576 * ftrace_location - return true if the ip giving is a traced location
1577 * @ip: the instruction pointer to check
1579 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1580 * That is, the instruction that is either a NOP or call to
1581 * the function tracer. It checks the ftrace internal tables to
1582 * determine if the address belongs or not.
1584 unsigned long ftrace_location(unsigned long ip)
1586 return ftrace_location_range(ip, ip);
1590 * ftrace_text_reserved - return true if range contains an ftrace location
1591 * @start: start of range to search
1592 * @end: end of range to search (inclusive). @end points to the last byte to check.
1594 * Returns 1 if @start and @end contains a ftrace location.
1595 * That is, the instruction that is either a NOP or call to
1596 * the function tracer. It checks the ftrace internal tables to
1597 * determine if the address belongs or not.
1599 int ftrace_text_reserved(const void *start, const void *end)
1603 ret = ftrace_location_range((unsigned long)start,
1604 (unsigned long)end);
1609 /* Test if ops registered to this rec needs regs */
1610 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1612 struct ftrace_ops *ops;
1613 bool keep_regs = false;
1615 for (ops = ftrace_ops_list;
1616 ops != &ftrace_list_end; ops = ops->next) {
1617 /* pass rec in as regs to have non-NULL val */
1618 if (ftrace_ops_test(ops, rec->ip, rec)) {
1619 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1629 static struct ftrace_ops *
1630 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1631 static struct ftrace_ops *
1632 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1634 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1638 struct ftrace_hash *hash;
1639 struct ftrace_hash *other_hash;
1640 struct ftrace_page *pg;
1641 struct dyn_ftrace *rec;
1642 bool update = false;
1646 /* Only update if the ops has been registered */
1647 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1651 * In the filter_hash case:
1652 * If the count is zero, we update all records.
1653 * Otherwise we just update the items in the hash.
1655 * In the notrace_hash case:
1656 * We enable the update in the hash.
1657 * As disabling notrace means enabling the tracing,
1658 * and enabling notrace means disabling, the inc variable
1662 hash = ops->func_hash->filter_hash;
1663 other_hash = ops->func_hash->notrace_hash;
1664 if (ftrace_hash_empty(hash))
1668 hash = ops->func_hash->notrace_hash;
1669 other_hash = ops->func_hash->filter_hash;
1671 * If the notrace hash has no items,
1672 * then there's nothing to do.
1674 if (ftrace_hash_empty(hash))
1678 do_for_each_ftrace_rec(pg, rec) {
1679 int in_other_hash = 0;
1683 if (rec->flags & FTRACE_FL_DISABLED)
1688 * Only the filter_hash affects all records.
1689 * Update if the record is not in the notrace hash.
1691 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1694 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1695 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1698 * If filter_hash is set, we want to match all functions
1699 * that are in the hash but not in the other hash.
1701 * If filter_hash is not set, then we are decrementing.
1702 * That means we match anything that is in the hash
1703 * and also in the other_hash. That is, we need to turn
1704 * off functions in the other hash because they are disabled
1707 if (filter_hash && in_hash && !in_other_hash)
1709 else if (!filter_hash && in_hash &&
1710 (in_other_hash || ftrace_hash_empty(other_hash)))
1718 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1721 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1722 rec->flags |= FTRACE_FL_DIRECT;
1725 * If there's only a single callback registered to a
1726 * function, and the ops has a trampoline registered
1727 * for it, then we can call it directly.
1729 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1730 rec->flags |= FTRACE_FL_TRAMP;
1733 * If we are adding another function callback
1734 * to this function, and the previous had a
1735 * custom trampoline in use, then we need to go
1736 * back to the default trampoline.
1738 rec->flags &= ~FTRACE_FL_TRAMP;
1741 * If any ops wants regs saved for this function
1742 * then all ops will get saved regs.
1744 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1745 rec->flags |= FTRACE_FL_REGS;
1747 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1752 * Only the internal direct_ops should have the
1753 * DIRECT flag set. Thus, if it is removing a
1754 * function, then that function should no longer
1757 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1758 rec->flags &= ~FTRACE_FL_DIRECT;
1761 * If the rec had REGS enabled and the ops that is
1762 * being removed had REGS set, then see if there is
1763 * still any ops for this record that wants regs.
1764 * If not, we can stop recording them.
1766 if (ftrace_rec_count(rec) > 0 &&
1767 rec->flags & FTRACE_FL_REGS &&
1768 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1769 if (!test_rec_ops_needs_regs(rec))
1770 rec->flags &= ~FTRACE_FL_REGS;
1774 * The TRAMP needs to be set only if rec count
1775 * is decremented to one, and the ops that is
1776 * left has a trampoline. As TRAMP can only be
1777 * enabled if there is only a single ops attached
1780 if (ftrace_rec_count(rec) == 1 &&
1781 ftrace_find_tramp_ops_any(rec))
1782 rec->flags |= FTRACE_FL_TRAMP;
1784 rec->flags &= ~FTRACE_FL_TRAMP;
1787 * flags will be cleared in ftrace_check_record()
1788 * if rec count is zero.
1793 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1794 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1796 /* Shortcut, if we handled all records, we are done. */
1797 if (!all && count == hash->count)
1799 } while_for_each_ftrace_rec();
1804 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1807 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1810 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1813 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1816 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1817 int filter_hash, int inc)
1819 struct ftrace_ops *op;
1821 __ftrace_hash_rec_update(ops, filter_hash, inc);
1823 if (ops->func_hash != &global_ops.local_hash)
1827 * If the ops shares the global_ops hash, then we need to update
1828 * all ops that are enabled and use this hash.
1830 do_for_each_ftrace_op(op, ftrace_ops_list) {
1834 if (op->func_hash == &global_ops.local_hash)
1835 __ftrace_hash_rec_update(op, filter_hash, inc);
1836 } while_for_each_ftrace_op(op);
1839 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1842 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1845 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1848 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1852 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1853 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1854 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1855 * Note that old_hash and new_hash has below meanings
1856 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1857 * - If the hash is EMPTY_HASH, it hits nothing
1858 * - Anything else hits the recs which match the hash entries.
1860 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1861 struct ftrace_hash *old_hash,
1862 struct ftrace_hash *new_hash)
1864 struct ftrace_page *pg;
1865 struct dyn_ftrace *rec, *end = NULL;
1868 /* Only update if the ops has been registered */
1869 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1872 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1876 * Since the IPMODIFY is a very address sensitive action, we do not
1877 * allow ftrace_ops to set all functions to new hash.
1879 if (!new_hash || !old_hash)
1882 /* Update rec->flags */
1883 do_for_each_ftrace_rec(pg, rec) {
1885 if (rec->flags & FTRACE_FL_DISABLED)
1888 /* We need to update only differences of filter_hash */
1889 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1890 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1891 if (in_old == in_new)
1895 /* New entries must ensure no others are using it */
1896 if (rec->flags & FTRACE_FL_IPMODIFY)
1898 rec->flags |= FTRACE_FL_IPMODIFY;
1899 } else /* Removed entry */
1900 rec->flags &= ~FTRACE_FL_IPMODIFY;
1901 } while_for_each_ftrace_rec();
1908 /* Roll back what we did above */
1909 do_for_each_ftrace_rec(pg, rec) {
1911 if (rec->flags & FTRACE_FL_DISABLED)
1917 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1918 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1919 if (in_old == in_new)
1923 rec->flags &= ~FTRACE_FL_IPMODIFY;
1925 rec->flags |= FTRACE_FL_IPMODIFY;
1926 } while_for_each_ftrace_rec();
1932 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1934 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1936 if (ftrace_hash_empty(hash))
1939 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1942 /* Disabling always succeeds */
1943 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1945 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1947 if (ftrace_hash_empty(hash))
1950 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1953 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1954 struct ftrace_hash *new_hash)
1956 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1958 if (ftrace_hash_empty(old_hash))
1961 if (ftrace_hash_empty(new_hash))
1964 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1967 static void print_ip_ins(const char *fmt, const unsigned char *p)
1971 printk(KERN_CONT "%s", fmt);
1973 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1974 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1977 enum ftrace_bug_type ftrace_bug_type;
1978 const void *ftrace_expected;
1980 static void print_bug_type(void)
1982 switch (ftrace_bug_type) {
1983 case FTRACE_BUG_UNKNOWN:
1985 case FTRACE_BUG_INIT:
1986 pr_info("Initializing ftrace call sites\n");
1988 case FTRACE_BUG_NOP:
1989 pr_info("Setting ftrace call site to NOP\n");
1991 case FTRACE_BUG_CALL:
1992 pr_info("Setting ftrace call site to call ftrace function\n");
1994 case FTRACE_BUG_UPDATE:
1995 pr_info("Updating ftrace call site to call a different ftrace function\n");
2001 * ftrace_bug - report and shutdown function tracer
2002 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2003 * @rec: The record that failed
2005 * The arch code that enables or disables the function tracing
2006 * can call ftrace_bug() when it has detected a problem in
2007 * modifying the code. @failed should be one of either:
2008 * EFAULT - if the problem happens on reading the @ip address
2009 * EINVAL - if what is read at @ip is not what was expected
2010 * EPERM - if the problem happens on writing to the @ip address
2012 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2014 unsigned long ip = rec ? rec->ip : 0;
2016 pr_info("------------[ ftrace bug ]------------\n");
2020 pr_info("ftrace faulted on modifying ");
2021 print_ip_sym(KERN_INFO, ip);
2024 pr_info("ftrace failed to modify ");
2025 print_ip_sym(KERN_INFO, ip);
2026 print_ip_ins(" actual: ", (unsigned char *)ip);
2028 if (ftrace_expected) {
2029 print_ip_ins(" expected: ", ftrace_expected);
2034 pr_info("ftrace faulted on writing ");
2035 print_ip_sym(KERN_INFO, ip);
2038 pr_info("ftrace faulted on unknown error ");
2039 print_ip_sym(KERN_INFO, ip);
2043 struct ftrace_ops *ops = NULL;
2045 pr_info("ftrace record flags: %lx\n", rec->flags);
2046 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2047 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2048 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2049 ops = ftrace_find_tramp_ops_any(rec);
2052 pr_cont("\ttramp: %pS (%pS)",
2053 (void *)ops->trampoline,
2055 ops = ftrace_find_tramp_ops_next(rec, ops);
2058 pr_cont("\ttramp: ERROR!");
2061 ip = ftrace_get_addr_curr(rec);
2062 pr_cont("\n expected tramp: %lx\n", ip);
2065 FTRACE_WARN_ON_ONCE(1);
2068 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2070 unsigned long flag = 0UL;
2072 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2074 if (rec->flags & FTRACE_FL_DISABLED)
2075 return FTRACE_UPDATE_IGNORE;
2078 * If we are updating calls:
2080 * If the record has a ref count, then we need to enable it
2081 * because someone is using it.
2083 * Otherwise we make sure its disabled.
2085 * If we are disabling calls, then disable all records that
2088 if (enable && ftrace_rec_count(rec))
2089 flag = FTRACE_FL_ENABLED;
2092 * If enabling and the REGS flag does not match the REGS_EN, or
2093 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2094 * this record. Set flags to fail the compare against ENABLED.
2095 * Same for direct calls.
2098 if (!(rec->flags & FTRACE_FL_REGS) !=
2099 !(rec->flags & FTRACE_FL_REGS_EN))
2100 flag |= FTRACE_FL_REGS;
2102 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2103 !(rec->flags & FTRACE_FL_TRAMP_EN))
2104 flag |= FTRACE_FL_TRAMP;
2107 * Direct calls are special, as count matters.
2108 * We must test the record for direct, if the
2109 * DIRECT and DIRECT_EN do not match, but only
2110 * if the count is 1. That's because, if the
2111 * count is something other than one, we do not
2112 * want the direct enabled (it will be done via the
2113 * direct helper). But if DIRECT_EN is set, and
2114 * the count is not one, we need to clear it.
2116 if (ftrace_rec_count(rec) == 1) {
2117 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2118 !(rec->flags & FTRACE_FL_DIRECT_EN))
2119 flag |= FTRACE_FL_DIRECT;
2120 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2121 flag |= FTRACE_FL_DIRECT;
2125 /* If the state of this record hasn't changed, then do nothing */
2126 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2127 return FTRACE_UPDATE_IGNORE;
2130 /* Save off if rec is being enabled (for return value) */
2131 flag ^= rec->flags & FTRACE_FL_ENABLED;
2134 rec->flags |= FTRACE_FL_ENABLED;
2135 if (flag & FTRACE_FL_REGS) {
2136 if (rec->flags & FTRACE_FL_REGS)
2137 rec->flags |= FTRACE_FL_REGS_EN;
2139 rec->flags &= ~FTRACE_FL_REGS_EN;
2141 if (flag & FTRACE_FL_TRAMP) {
2142 if (rec->flags & FTRACE_FL_TRAMP)
2143 rec->flags |= FTRACE_FL_TRAMP_EN;
2145 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2147 if (flag & FTRACE_FL_DIRECT) {
2149 * If there's only one user (direct_ops helper)
2150 * then we can call the direct function
2151 * directly (no ftrace trampoline).
2153 if (ftrace_rec_count(rec) == 1) {
2154 if (rec->flags & FTRACE_FL_DIRECT)
2155 rec->flags |= FTRACE_FL_DIRECT_EN;
2157 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2160 * Can only call directly if there's
2161 * only one callback to the function.
2163 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2169 * If this record is being updated from a nop, then
2170 * return UPDATE_MAKE_CALL.
2172 * return UPDATE_MODIFY_CALL to tell the caller to convert
2173 * from the save regs, to a non-save regs function or
2174 * vice versa, or from a trampoline call.
2176 if (flag & FTRACE_FL_ENABLED) {
2177 ftrace_bug_type = FTRACE_BUG_CALL;
2178 return FTRACE_UPDATE_MAKE_CALL;
2181 ftrace_bug_type = FTRACE_BUG_UPDATE;
2182 return FTRACE_UPDATE_MODIFY_CALL;
2186 /* If there's no more users, clear all flags */
2187 if (!ftrace_rec_count(rec))
2191 * Just disable the record, but keep the ops TRAMP
2192 * and REGS states. The _EN flags must be disabled though.
2194 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2195 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2198 ftrace_bug_type = FTRACE_BUG_NOP;
2199 return FTRACE_UPDATE_MAKE_NOP;
2203 * ftrace_update_record, set a record that now is tracing or not
2204 * @rec: the record to update
2205 * @enable: set to true if the record is tracing, false to force disable
2207 * The records that represent all functions that can be traced need
2208 * to be updated when tracing has been enabled.
2210 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2212 return ftrace_check_record(rec, enable, true);
2216 * ftrace_test_record, check if the record has been enabled or not
2217 * @rec: the record to test
2218 * @enable: set to true to check if enabled, false if it is disabled
2220 * The arch code may need to test if a record is already set to
2221 * tracing to determine how to modify the function code that it
2224 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2226 return ftrace_check_record(rec, enable, false);
2229 static struct ftrace_ops *
2230 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2232 struct ftrace_ops *op;
2233 unsigned long ip = rec->ip;
2235 do_for_each_ftrace_op(op, ftrace_ops_list) {
2237 if (!op->trampoline)
2240 if (hash_contains_ip(ip, op->func_hash))
2242 } while_for_each_ftrace_op(op);
2247 static struct ftrace_ops *
2248 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2249 struct ftrace_ops *op)
2251 unsigned long ip = rec->ip;
2253 while_for_each_ftrace_op(op) {
2255 if (!op->trampoline)
2258 if (hash_contains_ip(ip, op->func_hash))
2265 static struct ftrace_ops *
2266 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2268 struct ftrace_ops *op;
2269 unsigned long ip = rec->ip;
2272 * Need to check removed ops first.
2273 * If they are being removed, and this rec has a tramp,
2274 * and this rec is in the ops list, then it would be the
2275 * one with the tramp.
2278 if (hash_contains_ip(ip, &removed_ops->old_hash))
2283 * Need to find the current trampoline for a rec.
2284 * Now, a trampoline is only attached to a rec if there
2285 * was a single 'ops' attached to it. But this can be called
2286 * when we are adding another op to the rec or removing the
2287 * current one. Thus, if the op is being added, we can
2288 * ignore it because it hasn't attached itself to the rec
2291 * If an ops is being modified (hooking to different functions)
2292 * then we don't care about the new functions that are being
2293 * added, just the old ones (that are probably being removed).
2295 * If we are adding an ops to a function that already is using
2296 * a trampoline, it needs to be removed (trampolines are only
2297 * for single ops connected), then an ops that is not being
2298 * modified also needs to be checked.
2300 do_for_each_ftrace_op(op, ftrace_ops_list) {
2302 if (!op->trampoline)
2306 * If the ops is being added, it hasn't gotten to
2307 * the point to be removed from this tree yet.
2309 if (op->flags & FTRACE_OPS_FL_ADDING)
2314 * If the ops is being modified and is in the old
2315 * hash, then it is probably being removed from this
2318 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2319 hash_contains_ip(ip, &op->old_hash))
2322 * If the ops is not being added or modified, and it's
2323 * in its normal filter hash, then this must be the one
2326 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2327 hash_contains_ip(ip, op->func_hash))
2330 } while_for_each_ftrace_op(op);
2335 static struct ftrace_ops *
2336 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2338 struct ftrace_ops *op;
2339 unsigned long ip = rec->ip;
2341 do_for_each_ftrace_op(op, ftrace_ops_list) {
2342 /* pass rec in as regs to have non-NULL val */
2343 if (hash_contains_ip(ip, op->func_hash))
2345 } while_for_each_ftrace_op(op);
2350 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2351 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2352 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2353 static DEFINE_MUTEX(direct_mutex);
2354 int ftrace_direct_func_count;
2357 * Search the direct_functions hash to see if the given instruction pointer
2358 * has a direct caller attached to it.
2360 unsigned long ftrace_find_rec_direct(unsigned long ip)
2362 struct ftrace_func_entry *entry;
2364 entry = __ftrace_lookup_ip(direct_functions, ip);
2368 return entry->direct;
2371 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2372 struct ftrace_ops *ops, struct pt_regs *regs)
2376 addr = ftrace_find_rec_direct(ip);
2380 arch_ftrace_set_direct_caller(regs, addr);
2383 struct ftrace_ops direct_ops = {
2384 .func = call_direct_funcs,
2385 .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
2386 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2387 | FTRACE_OPS_FL_PERMANENT,
2389 * By declaring the main trampoline as this trampoline
2390 * it will never have one allocated for it. Allocated
2391 * trampolines should not call direct functions.
2392 * The direct_ops should only be called by the builtin
2393 * ftrace_regs_caller trampoline.
2395 .trampoline = FTRACE_REGS_ADDR,
2397 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2400 * ftrace_get_addr_new - Get the call address to set to
2401 * @rec: The ftrace record descriptor
2403 * If the record has the FTRACE_FL_REGS set, that means that it
2404 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2405 * is not set, then it wants to convert to the normal callback.
2407 * Returns the address of the trampoline to set to
2409 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2411 struct ftrace_ops *ops;
2414 if ((rec->flags & FTRACE_FL_DIRECT) &&
2415 (ftrace_rec_count(rec) == 1)) {
2416 addr = ftrace_find_rec_direct(rec->ip);
2422 /* Trampolines take precedence over regs */
2423 if (rec->flags & FTRACE_FL_TRAMP) {
2424 ops = ftrace_find_tramp_ops_new(rec);
2425 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2426 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2427 (void *)rec->ip, (void *)rec->ip, rec->flags);
2428 /* Ftrace is shutting down, return anything */
2429 return (unsigned long)FTRACE_ADDR;
2431 return ops->trampoline;
2434 if (rec->flags & FTRACE_FL_REGS)
2435 return (unsigned long)FTRACE_REGS_ADDR;
2437 return (unsigned long)FTRACE_ADDR;
2441 * ftrace_get_addr_curr - Get the call address that is already there
2442 * @rec: The ftrace record descriptor
2444 * The FTRACE_FL_REGS_EN is set when the record already points to
2445 * a function that saves all the regs. Basically the '_EN' version
2446 * represents the current state of the function.
2448 * Returns the address of the trampoline that is currently being called
2450 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2452 struct ftrace_ops *ops;
2455 /* Direct calls take precedence over trampolines */
2456 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2457 addr = ftrace_find_rec_direct(rec->ip);
2463 /* Trampolines take precedence over regs */
2464 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2465 ops = ftrace_find_tramp_ops_curr(rec);
2466 if (FTRACE_WARN_ON(!ops)) {
2467 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2468 (void *)rec->ip, (void *)rec->ip);
2469 /* Ftrace is shutting down, return anything */
2470 return (unsigned long)FTRACE_ADDR;
2472 return ops->trampoline;
2475 if (rec->flags & FTRACE_FL_REGS_EN)
2476 return (unsigned long)FTRACE_REGS_ADDR;
2478 return (unsigned long)FTRACE_ADDR;
2482 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2484 unsigned long ftrace_old_addr;
2485 unsigned long ftrace_addr;
2488 ftrace_addr = ftrace_get_addr_new(rec);
2490 /* This needs to be done before we call ftrace_update_record */
2491 ftrace_old_addr = ftrace_get_addr_curr(rec);
2493 ret = ftrace_update_record(rec, enable);
2495 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2498 case FTRACE_UPDATE_IGNORE:
2501 case FTRACE_UPDATE_MAKE_CALL:
2502 ftrace_bug_type = FTRACE_BUG_CALL;
2503 return ftrace_make_call(rec, ftrace_addr);
2505 case FTRACE_UPDATE_MAKE_NOP:
2506 ftrace_bug_type = FTRACE_BUG_NOP;
2507 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2509 case FTRACE_UPDATE_MODIFY_CALL:
2510 ftrace_bug_type = FTRACE_BUG_UPDATE;
2511 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2514 return -1; /* unknown ftrace bug */
2517 void __weak ftrace_replace_code(int mod_flags)
2519 struct dyn_ftrace *rec;
2520 struct ftrace_page *pg;
2521 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2522 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2525 if (unlikely(ftrace_disabled))
2528 do_for_each_ftrace_rec(pg, rec) {
2530 if (rec->flags & FTRACE_FL_DISABLED)
2533 failed = __ftrace_replace_code(rec, enable);
2535 ftrace_bug(failed, rec);
2536 /* Stop processing */
2541 } while_for_each_ftrace_rec();
2544 struct ftrace_rec_iter {
2545 struct ftrace_page *pg;
2550 * ftrace_rec_iter_start, start up iterating over traced functions
2552 * Returns an iterator handle that is used to iterate over all
2553 * the records that represent address locations where functions
2556 * May return NULL if no records are available.
2558 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2561 * We only use a single iterator.
2562 * Protected by the ftrace_lock mutex.
2564 static struct ftrace_rec_iter ftrace_rec_iter;
2565 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2567 iter->pg = ftrace_pages_start;
2570 /* Could have empty pages */
2571 while (iter->pg && !iter->pg->index)
2572 iter->pg = iter->pg->next;
2581 * ftrace_rec_iter_next, get the next record to process.
2582 * @iter: The handle to the iterator.
2584 * Returns the next iterator after the given iterator @iter.
2586 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2590 if (iter->index >= iter->pg->index) {
2591 iter->pg = iter->pg->next;
2594 /* Could have empty pages */
2595 while (iter->pg && !iter->pg->index)
2596 iter->pg = iter->pg->next;
2606 * ftrace_rec_iter_record, get the record at the iterator location
2607 * @iter: The current iterator location
2609 * Returns the record that the current @iter is at.
2611 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2613 return &iter->pg->records[iter->index];
2617 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2621 if (unlikely(ftrace_disabled))
2624 ret = ftrace_init_nop(mod, rec);
2626 ftrace_bug_type = FTRACE_BUG_INIT;
2627 ftrace_bug(ret, rec);
2634 * archs can override this function if they must do something
2635 * before the modifying code is performed.
2637 int __weak ftrace_arch_code_modify_prepare(void)
2643 * archs can override this function if they must do something
2644 * after the modifying code is performed.
2646 int __weak ftrace_arch_code_modify_post_process(void)
2651 void ftrace_modify_all_code(int command)
2653 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2657 if (command & FTRACE_MAY_SLEEP)
2658 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2661 * If the ftrace_caller calls a ftrace_ops func directly,
2662 * we need to make sure that it only traces functions it
2663 * expects to trace. When doing the switch of functions,
2664 * we need to update to the ftrace_ops_list_func first
2665 * before the transition between old and new calls are set,
2666 * as the ftrace_ops_list_func will check the ops hashes
2667 * to make sure the ops are having the right functions
2671 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2672 if (FTRACE_WARN_ON(err))
2676 if (command & FTRACE_UPDATE_CALLS)
2677 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2678 else if (command & FTRACE_DISABLE_CALLS)
2679 ftrace_replace_code(mod_flags);
2681 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2682 function_trace_op = set_function_trace_op;
2684 /* If irqs are disabled, we are in stop machine */
2685 if (!irqs_disabled())
2686 smp_call_function(ftrace_sync_ipi, NULL, 1);
2687 err = ftrace_update_ftrace_func(ftrace_trace_function);
2688 if (FTRACE_WARN_ON(err))
2692 if (command & FTRACE_START_FUNC_RET)
2693 err = ftrace_enable_ftrace_graph_caller();
2694 else if (command & FTRACE_STOP_FUNC_RET)
2695 err = ftrace_disable_ftrace_graph_caller();
2696 FTRACE_WARN_ON(err);
2699 static int __ftrace_modify_code(void *data)
2701 int *command = data;
2703 ftrace_modify_all_code(*command);
2709 * ftrace_run_stop_machine, go back to the stop machine method
2710 * @command: The command to tell ftrace what to do
2712 * If an arch needs to fall back to the stop machine method, the
2713 * it can call this function.
2715 void ftrace_run_stop_machine(int command)
2717 stop_machine(__ftrace_modify_code, &command, NULL);
2721 * arch_ftrace_update_code, modify the code to trace or not trace
2722 * @command: The command that needs to be done
2724 * Archs can override this function if it does not need to
2725 * run stop_machine() to modify code.
2727 void __weak arch_ftrace_update_code(int command)
2729 ftrace_run_stop_machine(command);
2732 static void ftrace_run_update_code(int command)
2736 ret = ftrace_arch_code_modify_prepare();
2737 FTRACE_WARN_ON(ret);
2742 * By default we use stop_machine() to modify the code.
2743 * But archs can do what ever they want as long as it
2744 * is safe. The stop_machine() is the safest, but also
2745 * produces the most overhead.
2747 arch_ftrace_update_code(command);
2749 ret = ftrace_arch_code_modify_post_process();
2750 FTRACE_WARN_ON(ret);
2753 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2754 struct ftrace_ops_hash *old_hash)
2756 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2757 ops->old_hash.filter_hash = old_hash->filter_hash;
2758 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2759 ftrace_run_update_code(command);
2760 ops->old_hash.filter_hash = NULL;
2761 ops->old_hash.notrace_hash = NULL;
2762 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2765 static ftrace_func_t saved_ftrace_func;
2766 static int ftrace_start_up;
2768 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2772 /* List of trace_ops that have allocated trampolines */
2773 static LIST_HEAD(ftrace_ops_trampoline_list);
2775 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2777 lockdep_assert_held(&ftrace_lock);
2778 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2781 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2783 lockdep_assert_held(&ftrace_lock);
2784 list_del_rcu(&ops->list);
2789 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2790 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2793 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2794 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2796 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2798 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2801 * Record the text poke event before the ksymbol unregister
2804 perf_event_text_poke((void *)ops->trampoline,
2805 (void *)ops->trampoline,
2806 ops->trampoline_size, NULL, 0);
2807 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2808 ops->trampoline, ops->trampoline_size,
2809 true, FTRACE_TRAMPOLINE_SYM);
2810 /* Remove from kallsyms after the perf events */
2811 ftrace_remove_trampoline_from_kallsyms(ops);
2814 arch_ftrace_trampoline_free(ops);
2817 static void ftrace_startup_enable(int command)
2819 if (saved_ftrace_func != ftrace_trace_function) {
2820 saved_ftrace_func = ftrace_trace_function;
2821 command |= FTRACE_UPDATE_TRACE_FUNC;
2824 if (!command || !ftrace_enabled)
2827 ftrace_run_update_code(command);
2830 static void ftrace_startup_all(int command)
2832 update_all_ops = true;
2833 ftrace_startup_enable(command);
2834 update_all_ops = false;
2837 int ftrace_startup(struct ftrace_ops *ops, int command)
2841 if (unlikely(ftrace_disabled))
2844 ret = __register_ftrace_function(ops);
2851 * Note that ftrace probes uses this to start up
2852 * and modify functions it will probe. But we still
2853 * set the ADDING flag for modification, as probes
2854 * do not have trampolines. If they add them in the
2855 * future, then the probes will need to distinguish
2856 * between adding and updating probes.
2858 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2860 ret = ftrace_hash_ipmodify_enable(ops);
2862 /* Rollback registration process */
2863 __unregister_ftrace_function(ops);
2865 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2866 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2867 ftrace_trampoline_free(ops);
2871 if (ftrace_hash_rec_enable(ops, 1))
2872 command |= FTRACE_UPDATE_CALLS;
2874 ftrace_startup_enable(command);
2876 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2881 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2885 if (unlikely(ftrace_disabled))
2888 ret = __unregister_ftrace_function(ops);
2894 * Just warn in case of unbalance, no need to kill ftrace, it's not
2895 * critical but the ftrace_call callers may be never nopped again after
2896 * further ftrace uses.
2898 WARN_ON_ONCE(ftrace_start_up < 0);
2900 /* Disabling ipmodify never fails */
2901 ftrace_hash_ipmodify_disable(ops);
2903 if (ftrace_hash_rec_disable(ops, 1))
2904 command |= FTRACE_UPDATE_CALLS;
2906 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2908 if (saved_ftrace_func != ftrace_trace_function) {
2909 saved_ftrace_func = ftrace_trace_function;
2910 command |= FTRACE_UPDATE_TRACE_FUNC;
2913 if (!command || !ftrace_enabled) {
2915 * If these are dynamic or per_cpu ops, they still
2916 * need their data freed. Since, function tracing is
2917 * not currently active, we can just free them
2918 * without synchronizing all CPUs.
2920 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2927 * If the ops uses a trampoline, then it needs to be
2928 * tested first on update.
2930 ops->flags |= FTRACE_OPS_FL_REMOVING;
2933 /* The trampoline logic checks the old hashes */
2934 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2935 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2937 ftrace_run_update_code(command);
2940 * If there's no more ops registered with ftrace, run a
2941 * sanity check to make sure all rec flags are cleared.
2943 if (rcu_dereference_protected(ftrace_ops_list,
2944 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2945 struct ftrace_page *pg;
2946 struct dyn_ftrace *rec;
2948 do_for_each_ftrace_rec(pg, rec) {
2949 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2950 pr_warn(" %pS flags:%lx\n",
2951 (void *)rec->ip, rec->flags);
2952 } while_for_each_ftrace_rec();
2955 ops->old_hash.filter_hash = NULL;
2956 ops->old_hash.notrace_hash = NULL;
2959 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2962 * Dynamic ops may be freed, we must make sure that all
2963 * callers are done before leaving this function.
2964 * The same goes for freeing the per_cpu data of the per_cpu
2967 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2969 * We need to do a hard force of sched synchronization.
2970 * This is because we use preempt_disable() to do RCU, but
2971 * the function tracers can be called where RCU is not watching
2972 * (like before user_exit()). We can not rely on the RCU
2973 * infrastructure to do the synchronization, thus we must do it
2976 synchronize_rcu_tasks_rude();
2979 * When the kernel is preemptive, tasks can be preempted
2980 * while on a ftrace trampoline. Just scheduling a task on
2981 * a CPU is not good enough to flush them. Calling
2982 * synchornize_rcu_tasks() will wait for those tasks to
2983 * execute and either schedule voluntarily or enter user space.
2985 if (IS_ENABLED(CONFIG_PREEMPTION))
2986 synchronize_rcu_tasks();
2989 ftrace_trampoline_free(ops);
2995 static void ftrace_startup_sysctl(void)
2999 if (unlikely(ftrace_disabled))
3002 /* Force update next time */
3003 saved_ftrace_func = NULL;
3004 /* ftrace_start_up is true if we want ftrace running */
3005 if (ftrace_start_up) {
3006 command = FTRACE_UPDATE_CALLS;
3007 if (ftrace_graph_active)
3008 command |= FTRACE_START_FUNC_RET;
3009 ftrace_startup_enable(command);
3013 static void ftrace_shutdown_sysctl(void)
3017 if (unlikely(ftrace_disabled))
3020 /* ftrace_start_up is true if ftrace is running */
3021 if (ftrace_start_up) {
3022 command = FTRACE_DISABLE_CALLS;
3023 if (ftrace_graph_active)
3024 command |= FTRACE_STOP_FUNC_RET;
3025 ftrace_run_update_code(command);
3029 static u64 ftrace_update_time;
3030 unsigned long ftrace_update_tot_cnt;
3031 unsigned long ftrace_number_of_pages;
3032 unsigned long ftrace_number_of_groups;
3034 static inline int ops_traces_mod(struct ftrace_ops *ops)
3037 * Filter_hash being empty will default to trace module.
3038 * But notrace hash requires a test of individual module functions.
3040 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3041 ftrace_hash_empty(ops->func_hash->notrace_hash);
3045 * Check if the current ops references the record.
3047 * If the ops traces all functions, then it was already accounted for.
3048 * If the ops does not trace the current record function, skip it.
3049 * If the ops ignores the function via notrace filter, skip it.
3052 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3054 /* If ops isn't enabled, ignore it */
3055 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3058 /* If ops traces all then it includes this function */
3059 if (ops_traces_mod(ops))
3062 /* The function must be in the filter */
3063 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3064 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3067 /* If in notrace hash, we ignore it too */
3068 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3074 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3076 struct ftrace_page *pg;
3077 struct dyn_ftrace *p;
3079 unsigned long update_cnt = 0;
3080 unsigned long rec_flags = 0;
3083 start = ftrace_now(raw_smp_processor_id());
3086 * When a module is loaded, this function is called to convert
3087 * the calls to mcount in its text to nops, and also to create
3088 * an entry in the ftrace data. Now, if ftrace is activated
3089 * after this call, but before the module sets its text to
3090 * read-only, the modification of enabling ftrace can fail if
3091 * the read-only is done while ftrace is converting the calls.
3092 * To prevent this, the module's records are set as disabled
3093 * and will be enabled after the call to set the module's text
3097 rec_flags |= FTRACE_FL_DISABLED;
3099 for (pg = new_pgs; pg; pg = pg->next) {
3101 for (i = 0; i < pg->index; i++) {
3103 /* If something went wrong, bail without enabling anything */
3104 if (unlikely(ftrace_disabled))
3107 p = &pg->records[i];
3108 p->flags = rec_flags;
3111 * Do the initial record conversion from mcount jump
3112 * to the NOP instructions.
3114 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3115 !ftrace_nop_initialize(mod, p))
3122 stop = ftrace_now(raw_smp_processor_id());
3123 ftrace_update_time = stop - start;
3124 ftrace_update_tot_cnt += update_cnt;
3129 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3135 if (WARN_ON(!count))
3138 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3139 order = get_count_order(pages);
3142 * We want to fill as much as possible. No more than a page
3145 if (!is_power_of_2(pages))
3149 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3152 /* if we can't allocate this size, try something smaller */
3159 ftrace_number_of_pages += 1 << order;
3160 ftrace_number_of_groups++;
3162 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3171 static struct ftrace_page *
3172 ftrace_allocate_pages(unsigned long num_to_init)
3174 struct ftrace_page *start_pg;
3175 struct ftrace_page *pg;
3182 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3187 * Try to allocate as much as possible in one continues
3188 * location that fills in all of the space. We want to
3189 * waste as little space as possible.
3192 cnt = ftrace_allocate_records(pg, num_to_init);
3200 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3212 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3213 free_pages((unsigned long)pg->records, order);
3214 start_pg = pg->next;
3217 ftrace_number_of_pages -= 1 << order;
3218 ftrace_number_of_groups--;
3220 pr_info("ftrace: FAILED to allocate memory for functions\n");
3224 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3226 struct ftrace_iterator {
3230 struct ftrace_page *pg;
3231 struct dyn_ftrace *func;
3232 struct ftrace_func_probe *probe;
3233 struct ftrace_func_entry *probe_entry;
3234 struct trace_parser parser;
3235 struct ftrace_hash *hash;
3236 struct ftrace_ops *ops;
3237 struct trace_array *tr;
3238 struct list_head *mod_list;
3245 t_probe_next(struct seq_file *m, loff_t *pos)
3247 struct ftrace_iterator *iter = m->private;
3248 struct trace_array *tr = iter->ops->private;
3249 struct list_head *func_probes;
3250 struct ftrace_hash *hash;
3251 struct list_head *next;
3252 struct hlist_node *hnd = NULL;
3253 struct hlist_head *hhd;
3262 func_probes = &tr->func_probes;
3263 if (list_empty(func_probes))
3267 next = func_probes->next;
3268 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3271 if (iter->probe_entry)
3272 hnd = &iter->probe_entry->hlist;
3274 hash = iter->probe->ops.func_hash->filter_hash;
3277 * A probe being registered may temporarily have an empty hash
3278 * and it's at the end of the func_probes list.
3280 if (!hash || hash == EMPTY_HASH)
3283 size = 1 << hash->size_bits;
3286 if (iter->pidx >= size) {
3287 if (iter->probe->list.next == func_probes)
3289 next = iter->probe->list.next;
3290 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3291 hash = iter->probe->ops.func_hash->filter_hash;
3292 size = 1 << hash->size_bits;
3296 hhd = &hash->buckets[iter->pidx];
3298 if (hlist_empty(hhd)) {
3314 if (WARN_ON_ONCE(!hnd))
3317 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3322 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3324 struct ftrace_iterator *iter = m->private;
3328 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3331 if (iter->mod_pos > *pos)
3335 iter->probe_entry = NULL;
3337 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3338 p = t_probe_next(m, &l);
3345 /* Only set this if we have an item */
3346 iter->flags |= FTRACE_ITER_PROBE;
3352 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3354 struct ftrace_func_entry *probe_entry;
3355 struct ftrace_probe_ops *probe_ops;
3356 struct ftrace_func_probe *probe;
3358 probe = iter->probe;
3359 probe_entry = iter->probe_entry;
3361 if (WARN_ON_ONCE(!probe || !probe_entry))
3364 probe_ops = probe->probe_ops;
3366 if (probe_ops->print)
3367 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3369 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3370 (void *)probe_ops->func);
3376 t_mod_next(struct seq_file *m, loff_t *pos)
3378 struct ftrace_iterator *iter = m->private;
3379 struct trace_array *tr = iter->tr;
3384 iter->mod_list = iter->mod_list->next;
3386 if (iter->mod_list == &tr->mod_trace ||
3387 iter->mod_list == &tr->mod_notrace) {
3388 iter->flags &= ~FTRACE_ITER_MOD;
3392 iter->mod_pos = *pos;
3397 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3399 struct ftrace_iterator *iter = m->private;
3403 if (iter->func_pos > *pos)
3406 iter->mod_pos = iter->func_pos;
3408 /* probes are only available if tr is set */
3412 for (l = 0; l <= (*pos - iter->func_pos); ) {
3413 p = t_mod_next(m, &l);
3418 iter->flags &= ~FTRACE_ITER_MOD;
3419 return t_probe_start(m, pos);
3422 /* Only set this if we have an item */
3423 iter->flags |= FTRACE_ITER_MOD;
3429 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3431 struct ftrace_mod_load *ftrace_mod;
3432 struct trace_array *tr = iter->tr;
3434 if (WARN_ON_ONCE(!iter->mod_list) ||
3435 iter->mod_list == &tr->mod_trace ||
3436 iter->mod_list == &tr->mod_notrace)
3439 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3441 if (ftrace_mod->func)
3442 seq_printf(m, "%s", ftrace_mod->func);
3446 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3452 t_func_next(struct seq_file *m, loff_t *pos)
3454 struct ftrace_iterator *iter = m->private;
3455 struct dyn_ftrace *rec = NULL;
3460 if (iter->idx >= iter->pg->index) {
3461 if (iter->pg->next) {
3462 iter->pg = iter->pg->next;
3467 rec = &iter->pg->records[iter->idx++];
3468 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3469 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3471 ((iter->flags & FTRACE_ITER_ENABLED) &&
3472 !(rec->flags & FTRACE_FL_ENABLED))) {
3482 iter->pos = iter->func_pos = *pos;
3489 t_next(struct seq_file *m, void *v, loff_t *pos)
3491 struct ftrace_iterator *iter = m->private;
3492 loff_t l = *pos; /* t_probe_start() must use original pos */
3495 if (unlikely(ftrace_disabled))
3498 if (iter->flags & FTRACE_ITER_PROBE)
3499 return t_probe_next(m, pos);
3501 if (iter->flags & FTRACE_ITER_MOD)
3502 return t_mod_next(m, pos);
3504 if (iter->flags & FTRACE_ITER_PRINTALL) {
3505 /* next must increment pos, and t_probe_start does not */
3507 return t_mod_start(m, &l);
3510 ret = t_func_next(m, pos);
3513 return t_mod_start(m, &l);
3518 static void reset_iter_read(struct ftrace_iterator *iter)
3522 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3525 static void *t_start(struct seq_file *m, loff_t *pos)
3527 struct ftrace_iterator *iter = m->private;
3531 mutex_lock(&ftrace_lock);
3533 if (unlikely(ftrace_disabled))
3537 * If an lseek was done, then reset and start from beginning.
3539 if (*pos < iter->pos)
3540 reset_iter_read(iter);
3543 * For set_ftrace_filter reading, if we have the filter
3544 * off, we can short cut and just print out that all
3545 * functions are enabled.
3547 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3548 ftrace_hash_empty(iter->hash)) {
3549 iter->func_pos = 1; /* Account for the message */
3551 return t_mod_start(m, pos);
3552 iter->flags |= FTRACE_ITER_PRINTALL;
3553 /* reset in case of seek/pread */
3554 iter->flags &= ~FTRACE_ITER_PROBE;
3558 if (iter->flags & FTRACE_ITER_MOD)
3559 return t_mod_start(m, pos);
3562 * Unfortunately, we need to restart at ftrace_pages_start
3563 * every time we let go of the ftrace_mutex. This is because
3564 * those pointers can change without the lock.
3566 iter->pg = ftrace_pages_start;
3568 for (l = 0; l <= *pos; ) {
3569 p = t_func_next(m, &l);
3575 return t_mod_start(m, pos);
3580 static void t_stop(struct seq_file *m, void *p)
3582 mutex_unlock(&ftrace_lock);
3586 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3591 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3592 struct dyn_ftrace *rec)
3596 ptr = arch_ftrace_trampoline_func(ops, rec);
3598 seq_printf(m, " ->%pS", ptr);
3601 static int t_show(struct seq_file *m, void *v)
3603 struct ftrace_iterator *iter = m->private;
3604 struct dyn_ftrace *rec;
3606 if (iter->flags & FTRACE_ITER_PROBE)
3607 return t_probe_show(m, iter);
3609 if (iter->flags & FTRACE_ITER_MOD)
3610 return t_mod_show(m, iter);
3612 if (iter->flags & FTRACE_ITER_PRINTALL) {
3613 if (iter->flags & FTRACE_ITER_NOTRACE)
3614 seq_puts(m, "#### no functions disabled ####\n");
3616 seq_puts(m, "#### all functions enabled ####\n");
3625 seq_printf(m, "%ps", (void *)rec->ip);
3626 if (iter->flags & FTRACE_ITER_ENABLED) {
3627 struct ftrace_ops *ops;
3629 seq_printf(m, " (%ld)%s%s%s",
3630 ftrace_rec_count(rec),
3631 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3632 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3633 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3634 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3635 ops = ftrace_find_tramp_ops_any(rec);
3638 seq_printf(m, "\ttramp: %pS (%pS)",
3639 (void *)ops->trampoline,
3641 add_trampoline_func(m, ops, rec);
3642 ops = ftrace_find_tramp_ops_next(rec, ops);
3645 seq_puts(m, "\ttramp: ERROR!");
3647 add_trampoline_func(m, NULL, rec);
3649 if (rec->flags & FTRACE_FL_DIRECT) {
3650 unsigned long direct;
3652 direct = ftrace_find_rec_direct(rec->ip);
3654 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3663 static const struct seq_operations show_ftrace_seq_ops = {
3671 ftrace_avail_open(struct inode *inode, struct file *file)
3673 struct ftrace_iterator *iter;
3676 ret = security_locked_down(LOCKDOWN_TRACEFS);
3680 if (unlikely(ftrace_disabled))
3683 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3687 iter->pg = ftrace_pages_start;
3688 iter->ops = &global_ops;
3694 ftrace_enabled_open(struct inode *inode, struct file *file)
3696 struct ftrace_iterator *iter;
3699 * This shows us what functions are currently being
3700 * traced and by what. Not sure if we want lockdown
3701 * to hide such critical information for an admin.
3702 * Although, perhaps it can show information we don't
3703 * want people to see, but if something is tracing
3704 * something, we probably want to know about it.
3707 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3711 iter->pg = ftrace_pages_start;
3712 iter->flags = FTRACE_ITER_ENABLED;
3713 iter->ops = &global_ops;
3719 * ftrace_regex_open - initialize function tracer filter files
3720 * @ops: The ftrace_ops that hold the hash filters
3721 * @flag: The type of filter to process
3722 * @inode: The inode, usually passed in to your open routine
3723 * @file: The file, usually passed in to your open routine
3725 * ftrace_regex_open() initializes the filter files for the
3726 * @ops. Depending on @flag it may process the filter hash or
3727 * the notrace hash of @ops. With this called from the open
3728 * routine, you can use ftrace_filter_write() for the write
3729 * routine if @flag has FTRACE_ITER_FILTER set, or
3730 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3731 * tracing_lseek() should be used as the lseek routine, and
3732 * release must call ftrace_regex_release().
3735 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3736 struct inode *inode, struct file *file)
3738 struct ftrace_iterator *iter;
3739 struct ftrace_hash *hash;
3740 struct list_head *mod_head;
3741 struct trace_array *tr = ops->private;
3744 ftrace_ops_init(ops);
3746 if (unlikely(ftrace_disabled))
3749 if (tracing_check_open_get_tr(tr))
3752 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3756 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3763 mutex_lock(&ops->func_hash->regex_lock);
3765 if (flag & FTRACE_ITER_NOTRACE) {
3766 hash = ops->func_hash->notrace_hash;
3767 mod_head = tr ? &tr->mod_notrace : NULL;
3769 hash = ops->func_hash->filter_hash;
3770 mod_head = tr ? &tr->mod_trace : NULL;
3773 iter->mod_list = mod_head;
3775 if (file->f_mode & FMODE_WRITE) {
3776 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3778 if (file->f_flags & O_TRUNC) {
3779 iter->hash = alloc_ftrace_hash(size_bits);
3780 clear_ftrace_mod_list(mod_head);
3782 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3786 trace_parser_put(&iter->parser);
3794 if (file->f_mode & FMODE_READ) {
3795 iter->pg = ftrace_pages_start;
3797 ret = seq_open(file, &show_ftrace_seq_ops);
3799 struct seq_file *m = file->private_data;
3803 free_ftrace_hash(iter->hash);
3804 trace_parser_put(&iter->parser);
3807 file->private_data = iter;
3810 mutex_unlock(&ops->func_hash->regex_lock);
3816 trace_array_put(tr);
3823 ftrace_filter_open(struct inode *inode, struct file *file)
3825 struct ftrace_ops *ops = inode->i_private;
3827 /* Checks for tracefs lockdown */
3828 return ftrace_regex_open(ops,
3829 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3834 ftrace_notrace_open(struct inode *inode, struct file *file)
3836 struct ftrace_ops *ops = inode->i_private;
3838 /* Checks for tracefs lockdown */
3839 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3843 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3844 struct ftrace_glob {
3851 * If symbols in an architecture don't correspond exactly to the user-visible
3852 * name of what they represent, it is possible to define this function to
3853 * perform the necessary adjustments.
3855 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3860 static int ftrace_match(char *str, struct ftrace_glob *g)
3865 str = arch_ftrace_match_adjust(str, g->search);
3869 if (strcmp(str, g->search) == 0)
3872 case MATCH_FRONT_ONLY:
3873 if (strncmp(str, g->search, g->len) == 0)
3876 case MATCH_MIDDLE_ONLY:
3877 if (strstr(str, g->search))
3880 case MATCH_END_ONLY:
3882 if (slen >= g->len &&
3883 memcmp(str + slen - g->len, g->search, g->len) == 0)
3887 if (glob_match(g->search, str))
3896 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3898 struct ftrace_func_entry *entry;
3901 entry = ftrace_lookup_ip(hash, rec->ip);
3903 /* Do nothing if it doesn't exist */
3907 free_hash_entry(hash, entry);
3909 /* Do nothing if it exists */
3913 ret = add_hash_entry(hash, rec->ip);
3919 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3922 long index = simple_strtoul(func_g->search, NULL, 0);
3923 struct ftrace_page *pg;
3924 struct dyn_ftrace *rec;
3926 /* The index starts at 1 */
3930 do_for_each_ftrace_rec(pg, rec) {
3931 if (pg->index <= index) {
3933 /* this is a double loop, break goes to the next page */
3936 rec = &pg->records[index];
3937 enter_record(hash, rec, clear_filter);
3939 } while_for_each_ftrace_rec();
3944 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3945 struct ftrace_glob *mod_g, int exclude_mod)
3947 char str[KSYM_SYMBOL_LEN];
3950 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3953 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3955 /* blank module name to match all modules */
3957 /* blank module globbing: modname xor exclude_mod */
3958 if (!exclude_mod != !modname)
3964 * exclude_mod is set to trace everything but the given
3965 * module. If it is set and the module matches, then
3966 * return 0. If it is not set, and the module doesn't match
3967 * also return 0. Otherwise, check the function to see if
3970 if (!mod_matches == !exclude_mod)
3973 /* blank search means to match all funcs in the mod */
3978 return ftrace_match(str, func_g);
3982 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3984 struct ftrace_page *pg;
3985 struct dyn_ftrace *rec;
3986 struct ftrace_glob func_g = { .type = MATCH_FULL };
3987 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3988 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3989 int exclude_mod = 0;
3992 int clear_filter = 0;
3995 func_g.type = filter_parse_regex(func, len, &func_g.search,
3997 func_g.len = strlen(func_g.search);
4001 mod_g.type = filter_parse_regex(mod, strlen(mod),
4002 &mod_g.search, &exclude_mod);
4003 mod_g.len = strlen(mod_g.search);
4006 mutex_lock(&ftrace_lock);
4008 if (unlikely(ftrace_disabled))
4011 if (func_g.type == MATCH_INDEX) {
4012 found = add_rec_by_index(hash, &func_g, clear_filter);
4016 do_for_each_ftrace_rec(pg, rec) {
4018 if (rec->flags & FTRACE_FL_DISABLED)
4021 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4022 ret = enter_record(hash, rec, clear_filter);
4029 } while_for_each_ftrace_rec();
4031 mutex_unlock(&ftrace_lock);
4037 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4039 return match_records(hash, buff, len, NULL);
4042 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4043 struct ftrace_ops_hash *old_hash)
4045 struct ftrace_ops *op;
4047 if (!ftrace_enabled)
4050 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4051 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4056 * If this is the shared global_ops filter, then we need to
4057 * check if there is another ops that shares it, is enabled.
4058 * If so, we still need to run the modify code.
4060 if (ops->func_hash != &global_ops.local_hash)
4063 do_for_each_ftrace_op(op, ftrace_ops_list) {
4064 if (op->func_hash == &global_ops.local_hash &&
4065 op->flags & FTRACE_OPS_FL_ENABLED) {
4066 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4067 /* Only need to do this once */
4070 } while_for_each_ftrace_op(op);
4073 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4074 struct ftrace_hash **orig_hash,
4075 struct ftrace_hash *hash,
4078 struct ftrace_ops_hash old_hash_ops;
4079 struct ftrace_hash *old_hash;
4082 old_hash = *orig_hash;
4083 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4084 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4085 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4087 ftrace_ops_update_code(ops, &old_hash_ops);
4088 free_ftrace_hash_rcu(old_hash);
4093 static bool module_exists(const char *module)
4095 /* All modules have the symbol __this_module */
4096 static const char this_mod[] = "__this_module";
4097 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4101 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4103 if (n > sizeof(modname) - 1)
4106 val = module_kallsyms_lookup_name(modname);
4110 static int cache_mod(struct trace_array *tr,
4111 const char *func, char *module, int enable)
4113 struct ftrace_mod_load *ftrace_mod, *n;
4114 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4117 mutex_lock(&ftrace_lock);
4119 /* We do not cache inverse filters */
4120 if (func[0] == '!') {
4124 /* Look to remove this hash */
4125 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4126 if (strcmp(ftrace_mod->module, module) != 0)
4129 /* no func matches all */
4130 if (strcmp(func, "*") == 0 ||
4131 (ftrace_mod->func &&
4132 strcmp(ftrace_mod->func, func) == 0)) {
4134 free_ftrace_mod(ftrace_mod);
4142 /* We only care about modules that have not been loaded yet */
4143 if (module_exists(module))
4146 /* Save this string off, and execute it when the module is loaded */
4147 ret = ftrace_add_mod(tr, func, module, enable);
4149 mutex_unlock(&ftrace_lock);
4155 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4156 int reset, int enable);
4158 #ifdef CONFIG_MODULES
4159 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4160 char *mod, bool enable)
4162 struct ftrace_mod_load *ftrace_mod, *n;
4163 struct ftrace_hash **orig_hash, *new_hash;
4164 LIST_HEAD(process_mods);
4168 mutex_lock(&ops->func_hash->regex_lock);
4171 orig_hash = &ops->func_hash->filter_hash;
4173 orig_hash = &ops->func_hash->notrace_hash;
4175 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4178 goto out; /* warn? */
4180 mutex_lock(&ftrace_lock);
4182 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4184 if (strcmp(ftrace_mod->module, mod) != 0)
4187 if (ftrace_mod->func)
4188 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4190 func = kstrdup("*", GFP_KERNEL);
4192 if (!func) /* warn? */
4195 list_del(&ftrace_mod->list);
4196 list_add(&ftrace_mod->list, &process_mods);
4198 /* Use the newly allocated func, as it may be "*" */
4199 kfree(ftrace_mod->func);
4200 ftrace_mod->func = func;
4203 mutex_unlock(&ftrace_lock);
4205 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4207 func = ftrace_mod->func;
4209 /* Grabs ftrace_lock, which is why we have this extra step */
4210 match_records(new_hash, func, strlen(func), mod);
4211 free_ftrace_mod(ftrace_mod);
4214 if (enable && list_empty(head))
4215 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4217 mutex_lock(&ftrace_lock);
4219 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4221 mutex_unlock(&ftrace_lock);
4224 mutex_unlock(&ops->func_hash->regex_lock);
4226 free_ftrace_hash(new_hash);
4229 static void process_cached_mods(const char *mod_name)
4231 struct trace_array *tr;
4234 mod = kstrdup(mod_name, GFP_KERNEL);
4238 mutex_lock(&trace_types_lock);
4239 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4240 if (!list_empty(&tr->mod_trace))
4241 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4242 if (!list_empty(&tr->mod_notrace))
4243 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4245 mutex_unlock(&trace_types_lock);
4252 * We register the module command as a template to show others how
4253 * to register the a command as well.
4257 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4258 char *func_orig, char *cmd, char *module, int enable)
4263 /* match_records() modifies func, and we need the original */
4264 func = kstrdup(func_orig, GFP_KERNEL);
4269 * cmd == 'mod' because we only registered this func
4270 * for the 'mod' ftrace_func_command.
4271 * But if you register one func with multiple commands,
4272 * you can tell which command was used by the cmd
4275 ret = match_records(hash, func, strlen(func), module);
4279 return cache_mod(tr, func_orig, module, enable);
4285 static struct ftrace_func_command ftrace_mod_cmd = {
4287 .func = ftrace_mod_callback,
4290 static int __init ftrace_mod_cmd_init(void)
4292 return register_ftrace_command(&ftrace_mod_cmd);
4294 core_initcall(ftrace_mod_cmd_init);
4296 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4297 struct ftrace_ops *op, struct pt_regs *pt_regs)
4299 struct ftrace_probe_ops *probe_ops;
4300 struct ftrace_func_probe *probe;
4302 probe = container_of(op, struct ftrace_func_probe, ops);
4303 probe_ops = probe->probe_ops;
4306 * Disable preemption for these calls to prevent a RCU grace
4307 * period. This syncs the hash iteration and freeing of items
4308 * on the hash. rcu_read_lock is too dangerous here.
4310 preempt_disable_notrace();
4311 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4312 preempt_enable_notrace();
4315 struct ftrace_func_map {
4316 struct ftrace_func_entry entry;
4320 struct ftrace_func_mapper {
4321 struct ftrace_hash hash;
4325 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4327 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4329 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4331 struct ftrace_hash *hash;
4334 * The mapper is simply a ftrace_hash, but since the entries
4335 * in the hash are not ftrace_func_entry type, we define it
4336 * as a separate structure.
4338 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4339 return (struct ftrace_func_mapper *)hash;
4343 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4344 * @mapper: The mapper that has the ip maps
4345 * @ip: the instruction pointer to find the data for
4347 * Returns the data mapped to @ip if found otherwise NULL. The return
4348 * is actually the address of the mapper data pointer. The address is
4349 * returned for use cases where the data is no bigger than a long, and
4350 * the user can use the data pointer as its data instead of having to
4351 * allocate more memory for the reference.
4353 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4356 struct ftrace_func_entry *entry;
4357 struct ftrace_func_map *map;
4359 entry = ftrace_lookup_ip(&mapper->hash, ip);
4363 map = (struct ftrace_func_map *)entry;
4368 * ftrace_func_mapper_add_ip - Map some data to an ip
4369 * @mapper: The mapper that has the ip maps
4370 * @ip: The instruction pointer address to map @data to
4371 * @data: The data to map to @ip
4373 * Returns 0 on success otherwise an error.
4375 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4376 unsigned long ip, void *data)
4378 struct ftrace_func_entry *entry;
4379 struct ftrace_func_map *map;
4381 entry = ftrace_lookup_ip(&mapper->hash, ip);
4385 map = kmalloc(sizeof(*map), GFP_KERNEL);
4392 __add_hash_entry(&mapper->hash, &map->entry);
4398 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4399 * @mapper: The mapper that has the ip maps
4400 * @ip: The instruction pointer address to remove the data from
4402 * Returns the data if it is found, otherwise NULL.
4403 * Note, if the data pointer is used as the data itself, (see
4404 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4405 * if the data pointer was set to zero.
4407 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4410 struct ftrace_func_entry *entry;
4411 struct ftrace_func_map *map;
4414 entry = ftrace_lookup_ip(&mapper->hash, ip);
4418 map = (struct ftrace_func_map *)entry;
4421 remove_hash_entry(&mapper->hash, entry);
4428 * free_ftrace_func_mapper - free a mapping of ips and data
4429 * @mapper: The mapper that has the ip maps
4430 * @free_func: A function to be called on each data item.
4432 * This is used to free the function mapper. The @free_func is optional
4433 * and can be used if the data needs to be freed as well.
4435 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4436 ftrace_mapper_func free_func)
4438 struct ftrace_func_entry *entry;
4439 struct ftrace_func_map *map;
4440 struct hlist_head *hhd;
4446 if (free_func && mapper->hash.count) {
4447 size = 1 << mapper->hash.size_bits;
4448 for (i = 0; i < size; i++) {
4449 hhd = &mapper->hash.buckets[i];
4450 hlist_for_each_entry(entry, hhd, hlist) {
4451 map = (struct ftrace_func_map *)entry;
4456 free_ftrace_hash(&mapper->hash);
4459 static void release_probe(struct ftrace_func_probe *probe)
4461 struct ftrace_probe_ops *probe_ops;
4463 mutex_lock(&ftrace_lock);
4465 WARN_ON(probe->ref <= 0);
4467 /* Subtract the ref that was used to protect this instance */
4471 probe_ops = probe->probe_ops;
4473 * Sending zero as ip tells probe_ops to free
4474 * the probe->data itself
4476 if (probe_ops->free)
4477 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4478 list_del(&probe->list);
4481 mutex_unlock(&ftrace_lock);
4484 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4487 * Add one ref to keep it from being freed when releasing the
4488 * ftrace_lock mutex.
4494 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4495 struct ftrace_probe_ops *probe_ops,
4498 struct ftrace_func_entry *entry;
4499 struct ftrace_func_probe *probe;
4500 struct ftrace_hash **orig_hash;
4501 struct ftrace_hash *old_hash;
4502 struct ftrace_hash *hash;
4511 /* We do not support '!' for function probes */
4512 if (WARN_ON(glob[0] == '!'))
4516 mutex_lock(&ftrace_lock);
4517 /* Check if the probe_ops is already registered */
4518 list_for_each_entry(probe, &tr->func_probes, list) {
4519 if (probe->probe_ops == probe_ops)
4522 if (&probe->list == &tr->func_probes) {
4523 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4525 mutex_unlock(&ftrace_lock);
4528 probe->probe_ops = probe_ops;
4529 probe->ops.func = function_trace_probe_call;
4531 ftrace_ops_init(&probe->ops);
4532 list_add(&probe->list, &tr->func_probes);
4535 acquire_probe_locked(probe);
4537 mutex_unlock(&ftrace_lock);
4540 * Note, there's a small window here that the func_hash->filter_hash
4541 * may be NULL or empty. Need to be careful when reading the loop.
4543 mutex_lock(&probe->ops.func_hash->regex_lock);
4545 orig_hash = &probe->ops.func_hash->filter_hash;
4546 old_hash = *orig_hash;
4547 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4554 ret = ftrace_match_records(hash, glob, strlen(glob));
4556 /* Nothing found? */
4563 size = 1 << hash->size_bits;
4564 for (i = 0; i < size; i++) {
4565 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4566 if (ftrace_lookup_ip(old_hash, entry->ip))
4569 * The caller might want to do something special
4570 * for each function we find. We call the callback
4571 * to give the caller an opportunity to do so.
4573 if (probe_ops->init) {
4574 ret = probe_ops->init(probe_ops, tr,
4578 if (probe_ops->free && count)
4579 probe_ops->free(probe_ops, tr,
4589 mutex_lock(&ftrace_lock);
4592 /* Nothing was added? */
4597 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4602 /* One ref for each new function traced */
4603 probe->ref += count;
4605 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4606 ret = ftrace_startup(&probe->ops, 0);
4609 mutex_unlock(&ftrace_lock);
4614 mutex_unlock(&probe->ops.func_hash->regex_lock);
4615 free_ftrace_hash(hash);
4617 release_probe(probe);
4622 if (!probe_ops->free || !count)
4625 /* Failed to do the move, need to call the free functions */
4626 for (i = 0; i < size; i++) {
4627 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4628 if (ftrace_lookup_ip(old_hash, entry->ip))
4630 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4637 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4638 struct ftrace_probe_ops *probe_ops)
4640 struct ftrace_ops_hash old_hash_ops;
4641 struct ftrace_func_entry *entry;
4642 struct ftrace_func_probe *probe;
4643 struct ftrace_glob func_g;
4644 struct ftrace_hash **orig_hash;
4645 struct ftrace_hash *old_hash;
4646 struct ftrace_hash *hash = NULL;
4647 struct hlist_node *tmp;
4648 struct hlist_head hhd;
4649 char str[KSYM_SYMBOL_LEN];
4651 int i, ret = -ENODEV;
4654 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4655 func_g.search = NULL;
4659 func_g.type = filter_parse_regex(glob, strlen(glob),
4660 &func_g.search, ¬);
4661 func_g.len = strlen(func_g.search);
4663 /* we do not support '!' for function probes */
4668 mutex_lock(&ftrace_lock);
4669 /* Check if the probe_ops is already registered */
4670 list_for_each_entry(probe, &tr->func_probes, list) {
4671 if (probe->probe_ops == probe_ops)
4674 if (&probe->list == &tr->func_probes)
4675 goto err_unlock_ftrace;
4678 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4679 goto err_unlock_ftrace;
4681 acquire_probe_locked(probe);
4683 mutex_unlock(&ftrace_lock);
4685 mutex_lock(&probe->ops.func_hash->regex_lock);
4687 orig_hash = &probe->ops.func_hash->filter_hash;
4688 old_hash = *orig_hash;
4690 if (ftrace_hash_empty(old_hash))
4693 old_hash_ops.filter_hash = old_hash;
4694 /* Probes only have filters */
4695 old_hash_ops.notrace_hash = NULL;
4698 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4702 INIT_HLIST_HEAD(&hhd);
4704 size = 1 << hash->size_bits;
4705 for (i = 0; i < size; i++) {
4706 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4708 if (func_g.search) {
4709 kallsyms_lookup(entry->ip, NULL, NULL,
4711 if (!ftrace_match(str, &func_g))
4715 remove_hash_entry(hash, entry);
4716 hlist_add_head(&entry->hlist, &hhd);
4720 /* Nothing found? */
4726 mutex_lock(&ftrace_lock);
4728 WARN_ON(probe->ref < count);
4730 probe->ref -= count;
4732 if (ftrace_hash_empty(hash))
4733 ftrace_shutdown(&probe->ops, 0);
4735 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4738 /* still need to update the function call sites */
4739 if (ftrace_enabled && !ftrace_hash_empty(hash))
4740 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4744 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4745 hlist_del(&entry->hlist);
4746 if (probe_ops->free)
4747 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4750 mutex_unlock(&ftrace_lock);
4753 mutex_unlock(&probe->ops.func_hash->regex_lock);
4754 free_ftrace_hash(hash);
4756 release_probe(probe);
4761 mutex_unlock(&ftrace_lock);
4765 void clear_ftrace_function_probes(struct trace_array *tr)
4767 struct ftrace_func_probe *probe, *n;
4769 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4770 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4773 static LIST_HEAD(ftrace_commands);
4774 static DEFINE_MUTEX(ftrace_cmd_mutex);
4777 * Currently we only register ftrace commands from __init, so mark this
4780 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4782 struct ftrace_func_command *p;
4785 mutex_lock(&ftrace_cmd_mutex);
4786 list_for_each_entry(p, &ftrace_commands, list) {
4787 if (strcmp(cmd->name, p->name) == 0) {
4792 list_add(&cmd->list, &ftrace_commands);
4794 mutex_unlock(&ftrace_cmd_mutex);
4800 * Currently we only unregister ftrace commands from __init, so mark
4803 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4805 struct ftrace_func_command *p, *n;
4808 mutex_lock(&ftrace_cmd_mutex);
4809 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4810 if (strcmp(cmd->name, p->name) == 0) {
4812 list_del_init(&p->list);
4817 mutex_unlock(&ftrace_cmd_mutex);
4822 static int ftrace_process_regex(struct ftrace_iterator *iter,
4823 char *buff, int len, int enable)
4825 struct ftrace_hash *hash = iter->hash;
4826 struct trace_array *tr = iter->ops->private;
4827 char *func, *command, *next = buff;
4828 struct ftrace_func_command *p;
4831 func = strsep(&next, ":");
4834 ret = ftrace_match_records(hash, func, len);
4844 command = strsep(&next, ":");
4846 mutex_lock(&ftrace_cmd_mutex);
4847 list_for_each_entry(p, &ftrace_commands, list) {
4848 if (strcmp(p->name, command) == 0) {
4849 ret = p->func(tr, hash, func, command, next, enable);
4854 mutex_unlock(&ftrace_cmd_mutex);
4860 ftrace_regex_write(struct file *file, const char __user *ubuf,
4861 size_t cnt, loff_t *ppos, int enable)
4863 struct ftrace_iterator *iter;
4864 struct trace_parser *parser;
4870 if (file->f_mode & FMODE_READ) {
4871 struct seq_file *m = file->private_data;
4874 iter = file->private_data;
4876 if (unlikely(ftrace_disabled))
4879 /* iter->hash is a local copy, so we don't need regex_lock */
4881 parser = &iter->parser;
4882 read = trace_get_user(parser, ubuf, cnt, ppos);
4884 if (read >= 0 && trace_parser_loaded(parser) &&
4885 !trace_parser_cont(parser)) {
4886 ret = ftrace_process_regex(iter, parser->buffer,
4887 parser->idx, enable);
4888 trace_parser_clear(parser);
4899 ftrace_filter_write(struct file *file, const char __user *ubuf,
4900 size_t cnt, loff_t *ppos)
4902 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4906 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4907 size_t cnt, loff_t *ppos)
4909 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4913 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4915 struct ftrace_func_entry *entry;
4917 if (!ftrace_location(ip))
4921 entry = ftrace_lookup_ip(hash, ip);
4924 free_hash_entry(hash, entry);
4928 return add_hash_entry(hash, ip);
4932 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4933 unsigned long ip, int remove, int reset, int enable)
4935 struct ftrace_hash **orig_hash;
4936 struct ftrace_hash *hash;
4939 if (unlikely(ftrace_disabled))
4942 mutex_lock(&ops->func_hash->regex_lock);
4945 orig_hash = &ops->func_hash->filter_hash;
4947 orig_hash = &ops->func_hash->notrace_hash;
4950 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4952 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4956 goto out_regex_unlock;
4959 if (buf && !ftrace_match_records(hash, buf, len)) {
4961 goto out_regex_unlock;
4964 ret = ftrace_match_addr(hash, ip, remove);
4966 goto out_regex_unlock;
4969 mutex_lock(&ftrace_lock);
4970 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4971 mutex_unlock(&ftrace_lock);
4974 mutex_unlock(&ops->func_hash->regex_lock);
4976 free_ftrace_hash(hash);
4981 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4982 int reset, int enable)
4984 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4987 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
4989 struct ftrace_direct_func {
4990 struct list_head next;
4995 static LIST_HEAD(ftrace_direct_funcs);
4998 * ftrace_find_direct_func - test an address if it is a registered direct caller
4999 * @addr: The address of a registered direct caller
5001 * This searches to see if a ftrace direct caller has been registered
5002 * at a specific address, and if so, it returns a descriptor for it.
5004 * This can be used by architecture code to see if an address is
5005 * a direct caller (trampoline) attached to a fentry/mcount location.
5006 * This is useful for the function_graph tracer, as it may need to
5007 * do adjustments if it traced a location that also has a direct
5008 * trampoline attached to it.
5010 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5012 struct ftrace_direct_func *entry;
5015 /* May be called by fgraph trampoline (protected by rcu tasks) */
5016 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5017 if (entry->addr == addr) {
5029 * register_ftrace_direct - Call a custom trampoline directly
5030 * @ip: The address of the nop at the beginning of a function
5031 * @addr: The address of the trampoline to call at @ip
5033 * This is used to connect a direct call from the nop location (@ip)
5034 * at the start of ftrace traced functions. The location that it calls
5035 * (@addr) must be able to handle a direct call, and save the parameters
5036 * of the function being traced, and restore them (or inject new ones
5037 * if needed), before returning.
5041 * -EBUSY - Another direct function is already attached (there can be only one)
5042 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5043 * -ENOMEM - There was an allocation failure.
5045 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5047 struct ftrace_direct_func *direct;
5048 struct ftrace_func_entry *entry;
5049 struct ftrace_hash *free_hash = NULL;
5050 struct dyn_ftrace *rec;
5053 mutex_lock(&direct_mutex);
5055 /* See if there's a direct function at @ip already */
5056 if (ftrace_find_rec_direct(ip))
5060 rec = lookup_rec(ip, ip);
5065 * Check if the rec says it has a direct call but we didn't
5068 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5071 /* Make sure the ip points to the exact record */
5072 if (ip != rec->ip) {
5074 /* Need to check this ip for a direct. */
5075 if (ftrace_find_rec_direct(ip))
5080 if (ftrace_hash_empty(direct_functions) ||
5081 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5082 struct ftrace_hash *new_hash;
5083 int size = ftrace_hash_empty(direct_functions) ? 0 :
5084 direct_functions->count + 1;
5089 new_hash = dup_hash(direct_functions, size);
5093 free_hash = direct_functions;
5094 direct_functions = new_hash;
5097 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5101 direct = ftrace_find_direct_func(addr);
5103 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5108 direct->addr = addr;
5110 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5111 ftrace_direct_func_count++;
5115 entry->direct = addr;
5116 __add_hash_entry(direct_functions, entry);
5118 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5120 remove_hash_entry(direct_functions, entry);
5122 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5123 ret = register_ftrace_function(&direct_ops);
5125 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5130 if (!direct->count) {
5131 list_del_rcu(&direct->next);
5132 synchronize_rcu_tasks();
5135 free_ftrace_hash(free_hash);
5137 ftrace_direct_func_count--;
5143 mutex_unlock(&direct_mutex);
5146 synchronize_rcu_tasks();
5147 free_ftrace_hash(free_hash);
5152 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5154 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5155 struct dyn_ftrace **recp)
5157 struct ftrace_func_entry *entry;
5158 struct dyn_ftrace *rec;
5160 rec = lookup_rec(*ip, *ip);
5164 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5166 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5170 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5172 /* Passed in ip just needs to be on the call site */
5181 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5183 struct ftrace_direct_func *direct;
5184 struct ftrace_func_entry *entry;
5187 mutex_lock(&direct_mutex);
5189 entry = find_direct_entry(&ip, NULL);
5193 if (direct_functions->count == 1)
5194 unregister_ftrace_function(&direct_ops);
5196 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5200 remove_hash_entry(direct_functions, entry);
5202 direct = ftrace_find_direct_func(addr);
5203 if (!WARN_ON(!direct)) {
5204 /* This is the good path (see the ! before WARN) */
5206 WARN_ON(direct->count < 0);
5207 if (!direct->count) {
5208 list_del_rcu(&direct->next);
5209 synchronize_rcu_tasks();
5212 ftrace_direct_func_count--;
5216 mutex_unlock(&direct_mutex);
5220 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5222 static struct ftrace_ops stub_ops = {
5223 .func = ftrace_stub,
5227 * ftrace_modify_direct_caller - modify ftrace nop directly
5228 * @entry: The ftrace hash entry of the direct helper for @rec
5229 * @rec: The record representing the function site to patch
5230 * @old_addr: The location that the site at @rec->ip currently calls
5231 * @new_addr: The location that the site at @rec->ip should call
5233 * An architecture may overwrite this function to optimize the
5234 * changing of the direct callback on an ftrace nop location.
5235 * This is called with the ftrace_lock mutex held, and no other
5236 * ftrace callbacks are on the associated record (@rec). Thus,
5237 * it is safe to modify the ftrace record, where it should be
5238 * currently calling @old_addr directly, to call @new_addr.
5240 * Safety checks should be made to make sure that the code at
5241 * @rec->ip is currently calling @old_addr. And this must
5242 * also update entry->direct to @new_addr.
5244 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5245 struct dyn_ftrace *rec,
5246 unsigned long old_addr,
5247 unsigned long new_addr)
5249 unsigned long ip = rec->ip;
5253 * The ftrace_lock was used to determine if the record
5254 * had more than one registered user to it. If it did,
5255 * we needed to prevent that from changing to do the quick
5256 * switch. But if it did not (only a direct caller was attached)
5257 * then this function is called. But this function can deal
5258 * with attached callers to the rec that we care about, and
5259 * since this function uses standard ftrace calls that take
5260 * the ftrace_lock mutex, we need to release it.
5262 mutex_unlock(&ftrace_lock);
5265 * By setting a stub function at the same address, we force
5266 * the code to call the iterator and the direct_ops helper.
5267 * This means that @ip does not call the direct call, and
5268 * we can simply modify it.
5270 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5274 ret = register_ftrace_function(&stub_ops);
5276 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5280 entry->direct = new_addr;
5283 * By removing the stub, we put back the direct call, calling
5286 unregister_ftrace_function(&stub_ops);
5287 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5290 mutex_lock(&ftrace_lock);
5296 * modify_ftrace_direct - Modify an existing direct call to call something else
5297 * @ip: The instruction pointer to modify
5298 * @old_addr: The address that the current @ip calls directly
5299 * @new_addr: The address that the @ip should call
5301 * This modifies a ftrace direct caller at an instruction pointer without
5302 * having to disable it first. The direct call will switch over to the
5303 * @new_addr without missing anything.
5305 * Returns: zero on success. Non zero on error, which includes:
5306 * -ENODEV : the @ip given has no direct caller attached
5307 * -EINVAL : the @old_addr does not match the current direct caller
5309 int modify_ftrace_direct(unsigned long ip,
5310 unsigned long old_addr, unsigned long new_addr)
5312 struct ftrace_func_entry *entry;
5313 struct dyn_ftrace *rec;
5316 mutex_lock(&direct_mutex);
5318 mutex_lock(&ftrace_lock);
5319 entry = find_direct_entry(&ip, &rec);
5324 if (entry->direct != old_addr)
5328 * If there's no other ftrace callback on the rec->ip location,
5329 * then it can be changed directly by the architecture.
5330 * If there is another caller, then we just need to change the
5331 * direct caller helper to point to @new_addr.
5333 if (ftrace_rec_count(rec) == 1) {
5334 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5336 entry->direct = new_addr;
5341 mutex_unlock(&ftrace_lock);
5342 mutex_unlock(&direct_mutex);
5345 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5346 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5349 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5350 * @ops - the ops to set the filter with
5351 * @ip - the address to add to or remove from the filter.
5352 * @remove - non zero to remove the ip from the filter
5353 * @reset - non zero to reset all filters before applying this filter.
5355 * Filters denote which functions should be enabled when tracing is enabled
5356 * If @ip is NULL, it failes to update filter.
5358 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5359 int remove, int reset)
5361 ftrace_ops_init(ops);
5362 return ftrace_set_addr(ops, ip, remove, reset, 1);
5364 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5367 * ftrace_ops_set_global_filter - setup ops to use global filters
5368 * @ops - the ops which will use the global filters
5370 * ftrace users who need global function trace filtering should call this.
5371 * It can set the global filter only if ops were not initialized before.
5373 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5375 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5378 ftrace_ops_init(ops);
5379 ops->func_hash = &global_ops.local_hash;
5381 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5384 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5385 int reset, int enable)
5387 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5391 * ftrace_set_filter - set a function to filter on in ftrace
5392 * @ops - the ops to set the filter with
5393 * @buf - the string that holds the function filter text.
5394 * @len - the length of the string.
5395 * @reset - non zero to reset all filters before applying this filter.
5397 * Filters denote which functions should be enabled when tracing is enabled.
5398 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5400 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5403 ftrace_ops_init(ops);
5404 return ftrace_set_regex(ops, buf, len, reset, 1);
5406 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5409 * ftrace_set_notrace - set a function to not trace in ftrace
5410 * @ops - the ops to set the notrace filter with
5411 * @buf - the string that holds the function notrace text.
5412 * @len - the length of the string.
5413 * @reset - non zero to reset all filters before applying this filter.
5415 * Notrace Filters denote which functions should not be enabled when tracing
5416 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5419 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5422 ftrace_ops_init(ops);
5423 return ftrace_set_regex(ops, buf, len, reset, 0);
5425 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5427 * ftrace_set_global_filter - set a function to filter on with global tracers
5428 * @buf - the string that holds the function filter text.
5429 * @len - the length of the string.
5430 * @reset - non zero to reset all filters before applying this filter.
5432 * Filters denote which functions should be enabled when tracing is enabled.
5433 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5435 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5437 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5439 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5442 * ftrace_set_global_notrace - set a function to not trace with global tracers
5443 * @buf - the string that holds the function notrace text.
5444 * @len - the length of the string.
5445 * @reset - non zero to reset all filters before applying this filter.
5447 * Notrace Filters denote which functions should not be enabled when tracing
5448 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5451 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5453 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5455 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5458 * command line interface to allow users to set filters on boot up.
5460 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5461 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5462 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5464 /* Used by function selftest to not test if filter is set */
5465 bool ftrace_filter_param __initdata;
5467 static int __init set_ftrace_notrace(char *str)
5469 ftrace_filter_param = true;
5470 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5473 __setup("ftrace_notrace=", set_ftrace_notrace);
5475 static int __init set_ftrace_filter(char *str)
5477 ftrace_filter_param = true;
5478 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5481 __setup("ftrace_filter=", set_ftrace_filter);
5483 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5484 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5485 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5486 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5488 static int __init set_graph_function(char *str)
5490 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5493 __setup("ftrace_graph_filter=", set_graph_function);
5495 static int __init set_graph_notrace_function(char *str)
5497 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5500 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5502 static int __init set_graph_max_depth_function(char *str)
5506 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5509 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5511 static void __init set_ftrace_early_graph(char *buf, int enable)
5515 struct ftrace_hash *hash;
5517 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5518 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5522 func = strsep(&buf, ",");
5523 /* we allow only one expression at a time */
5524 ret = ftrace_graph_set_hash(hash, func);
5526 printk(KERN_DEBUG "ftrace: function %s not "
5527 "traceable\n", func);
5531 ftrace_graph_hash = hash;
5533 ftrace_graph_notrace_hash = hash;
5535 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5538 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5542 ftrace_ops_init(ops);
5545 func = strsep(&buf, ",");
5546 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5550 static void __init set_ftrace_early_filters(void)
5552 if (ftrace_filter_buf[0])
5553 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5554 if (ftrace_notrace_buf[0])
5555 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5556 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5557 if (ftrace_graph_buf[0])
5558 set_ftrace_early_graph(ftrace_graph_buf, 1);
5559 if (ftrace_graph_notrace_buf[0])
5560 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5561 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5564 int ftrace_regex_release(struct inode *inode, struct file *file)
5566 struct seq_file *m = (struct seq_file *)file->private_data;
5567 struct ftrace_iterator *iter;
5568 struct ftrace_hash **orig_hash;
5569 struct trace_parser *parser;
5573 if (file->f_mode & FMODE_READ) {
5575 seq_release(inode, file);
5577 iter = file->private_data;
5579 parser = &iter->parser;
5580 if (trace_parser_loaded(parser)) {
5581 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5584 trace_parser_put(parser);
5586 mutex_lock(&iter->ops->func_hash->regex_lock);
5588 if (file->f_mode & FMODE_WRITE) {
5589 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5592 orig_hash = &iter->ops->func_hash->filter_hash;
5593 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5594 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5596 orig_hash = &iter->ops->func_hash->notrace_hash;
5598 mutex_lock(&ftrace_lock);
5599 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5600 iter->hash, filter_hash);
5601 mutex_unlock(&ftrace_lock);
5603 /* For read only, the hash is the ops hash */
5607 mutex_unlock(&iter->ops->func_hash->regex_lock);
5608 free_ftrace_hash(iter->hash);
5610 trace_array_put(iter->tr);
5616 static const struct file_operations ftrace_avail_fops = {
5617 .open = ftrace_avail_open,
5619 .llseek = seq_lseek,
5620 .release = seq_release_private,
5623 static const struct file_operations ftrace_enabled_fops = {
5624 .open = ftrace_enabled_open,
5626 .llseek = seq_lseek,
5627 .release = seq_release_private,
5630 static const struct file_operations ftrace_filter_fops = {
5631 .open = ftrace_filter_open,
5633 .write = ftrace_filter_write,
5634 .llseek = tracing_lseek,
5635 .release = ftrace_regex_release,
5638 static const struct file_operations ftrace_notrace_fops = {
5639 .open = ftrace_notrace_open,
5641 .write = ftrace_notrace_write,
5642 .llseek = tracing_lseek,
5643 .release = ftrace_regex_release,
5646 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5648 static DEFINE_MUTEX(graph_lock);
5650 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5651 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5653 enum graph_filter_type {
5654 GRAPH_FILTER_NOTRACE = 0,
5655 GRAPH_FILTER_FUNCTION,
5658 #define FTRACE_GRAPH_EMPTY ((void *)1)
5660 struct ftrace_graph_data {
5661 struct ftrace_hash *hash;
5662 struct ftrace_func_entry *entry;
5663 int idx; /* for hash table iteration */
5664 enum graph_filter_type type;
5665 struct ftrace_hash *new_hash;
5666 const struct seq_operations *seq_ops;
5667 struct trace_parser parser;
5671 __g_next(struct seq_file *m, loff_t *pos)
5673 struct ftrace_graph_data *fgd = m->private;
5674 struct ftrace_func_entry *entry = fgd->entry;
5675 struct hlist_head *head;
5676 int i, idx = fgd->idx;
5678 if (*pos >= fgd->hash->count)
5682 hlist_for_each_entry_continue(entry, hlist) {
5690 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5691 head = &fgd->hash->buckets[i];
5692 hlist_for_each_entry(entry, head, hlist) {
5702 g_next(struct seq_file *m, void *v, loff_t *pos)
5705 return __g_next(m, pos);
5708 static void *g_start(struct seq_file *m, loff_t *pos)
5710 struct ftrace_graph_data *fgd = m->private;
5712 mutex_lock(&graph_lock);
5714 if (fgd->type == GRAPH_FILTER_FUNCTION)
5715 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5716 lockdep_is_held(&graph_lock));
5718 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5719 lockdep_is_held(&graph_lock));
5721 /* Nothing, tell g_show to print all functions are enabled */
5722 if (ftrace_hash_empty(fgd->hash) && !*pos)
5723 return FTRACE_GRAPH_EMPTY;
5727 return __g_next(m, pos);
5730 static void g_stop(struct seq_file *m, void *p)
5732 mutex_unlock(&graph_lock);
5735 static int g_show(struct seq_file *m, void *v)
5737 struct ftrace_func_entry *entry = v;
5742 if (entry == FTRACE_GRAPH_EMPTY) {
5743 struct ftrace_graph_data *fgd = m->private;
5745 if (fgd->type == GRAPH_FILTER_FUNCTION)
5746 seq_puts(m, "#### all functions enabled ####\n");
5748 seq_puts(m, "#### no functions disabled ####\n");
5752 seq_printf(m, "%ps\n", (void *)entry->ip);
5757 static const struct seq_operations ftrace_graph_seq_ops = {
5765 __ftrace_graph_open(struct inode *inode, struct file *file,
5766 struct ftrace_graph_data *fgd)
5769 struct ftrace_hash *new_hash = NULL;
5771 ret = security_locked_down(LOCKDOWN_TRACEFS);
5775 if (file->f_mode & FMODE_WRITE) {
5776 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5778 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5781 if (file->f_flags & O_TRUNC)
5782 new_hash = alloc_ftrace_hash(size_bits);
5784 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5792 if (file->f_mode & FMODE_READ) {
5793 ret = seq_open(file, &ftrace_graph_seq_ops);
5795 struct seq_file *m = file->private_data;
5799 free_ftrace_hash(new_hash);
5803 file->private_data = fgd;
5806 if (ret < 0 && file->f_mode & FMODE_WRITE)
5807 trace_parser_put(&fgd->parser);
5809 fgd->new_hash = new_hash;
5812 * All uses of fgd->hash must be taken with the graph_lock
5813 * held. The graph_lock is going to be released, so force
5814 * fgd->hash to be reinitialized when it is taken again.
5822 ftrace_graph_open(struct inode *inode, struct file *file)
5824 struct ftrace_graph_data *fgd;
5827 if (unlikely(ftrace_disabled))
5830 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5834 mutex_lock(&graph_lock);
5836 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5837 lockdep_is_held(&graph_lock));
5838 fgd->type = GRAPH_FILTER_FUNCTION;
5839 fgd->seq_ops = &ftrace_graph_seq_ops;
5841 ret = __ftrace_graph_open(inode, file, fgd);
5845 mutex_unlock(&graph_lock);
5850 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5852 struct ftrace_graph_data *fgd;
5855 if (unlikely(ftrace_disabled))
5858 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5862 mutex_lock(&graph_lock);
5864 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5865 lockdep_is_held(&graph_lock));
5866 fgd->type = GRAPH_FILTER_NOTRACE;
5867 fgd->seq_ops = &ftrace_graph_seq_ops;
5869 ret = __ftrace_graph_open(inode, file, fgd);
5873 mutex_unlock(&graph_lock);
5878 ftrace_graph_release(struct inode *inode, struct file *file)
5880 struct ftrace_graph_data *fgd;
5881 struct ftrace_hash *old_hash, *new_hash;
5882 struct trace_parser *parser;
5885 if (file->f_mode & FMODE_READ) {
5886 struct seq_file *m = file->private_data;
5889 seq_release(inode, file);
5891 fgd = file->private_data;
5895 if (file->f_mode & FMODE_WRITE) {
5897 parser = &fgd->parser;
5899 if (trace_parser_loaded((parser))) {
5900 ret = ftrace_graph_set_hash(fgd->new_hash,
5904 trace_parser_put(parser);
5906 new_hash = __ftrace_hash_move(fgd->new_hash);
5912 mutex_lock(&graph_lock);
5914 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5915 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5916 lockdep_is_held(&graph_lock));
5917 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5919 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5920 lockdep_is_held(&graph_lock));
5921 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5924 mutex_unlock(&graph_lock);
5927 * We need to do a hard force of sched synchronization.
5928 * This is because we use preempt_disable() to do RCU, but
5929 * the function tracers can be called where RCU is not watching
5930 * (like before user_exit()). We can not rely on the RCU
5931 * infrastructure to do the synchronization, thus we must do it
5934 synchronize_rcu_tasks_rude();
5936 free_ftrace_hash(old_hash);
5940 free_ftrace_hash(fgd->new_hash);
5947 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5949 struct ftrace_glob func_g;
5950 struct dyn_ftrace *rec;
5951 struct ftrace_page *pg;
5952 struct ftrace_func_entry *entry;
5957 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5958 &func_g.search, ¬);
5960 func_g.len = strlen(func_g.search);
5962 mutex_lock(&ftrace_lock);
5964 if (unlikely(ftrace_disabled)) {
5965 mutex_unlock(&ftrace_lock);
5969 do_for_each_ftrace_rec(pg, rec) {
5971 if (rec->flags & FTRACE_FL_DISABLED)
5974 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5975 entry = ftrace_lookup_ip(hash, rec->ip);
5982 if (add_hash_entry(hash, rec->ip) < 0)
5986 free_hash_entry(hash, entry);
5991 } while_for_each_ftrace_rec();
5993 mutex_unlock(&ftrace_lock);
6002 ftrace_graph_write(struct file *file, const char __user *ubuf,
6003 size_t cnt, loff_t *ppos)
6005 ssize_t read, ret = 0;
6006 struct ftrace_graph_data *fgd = file->private_data;
6007 struct trace_parser *parser;
6012 /* Read mode uses seq functions */
6013 if (file->f_mode & FMODE_READ) {
6014 struct seq_file *m = file->private_data;
6018 parser = &fgd->parser;
6020 read = trace_get_user(parser, ubuf, cnt, ppos);
6022 if (read >= 0 && trace_parser_loaded(parser) &&
6023 !trace_parser_cont(parser)) {
6025 ret = ftrace_graph_set_hash(fgd->new_hash,
6027 trace_parser_clear(parser);
6036 static const struct file_operations ftrace_graph_fops = {
6037 .open = ftrace_graph_open,
6039 .write = ftrace_graph_write,
6040 .llseek = tracing_lseek,
6041 .release = ftrace_graph_release,
6044 static const struct file_operations ftrace_graph_notrace_fops = {
6045 .open = ftrace_graph_notrace_open,
6047 .write = ftrace_graph_write,
6048 .llseek = tracing_lseek,
6049 .release = ftrace_graph_release,
6051 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6053 void ftrace_create_filter_files(struct ftrace_ops *ops,
6054 struct dentry *parent)
6057 trace_create_file("set_ftrace_filter", 0644, parent,
6058 ops, &ftrace_filter_fops);
6060 trace_create_file("set_ftrace_notrace", 0644, parent,
6061 ops, &ftrace_notrace_fops);
6065 * The name "destroy_filter_files" is really a misnomer. Although
6066 * in the future, it may actually delete the files, but this is
6067 * really intended to make sure the ops passed in are disabled
6068 * and that when this function returns, the caller is free to
6071 * The "destroy" name is only to match the "create" name that this
6072 * should be paired with.
6074 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6076 mutex_lock(&ftrace_lock);
6077 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6078 ftrace_shutdown(ops, 0);
6079 ops->flags |= FTRACE_OPS_FL_DELETED;
6080 ftrace_free_filter(ops);
6081 mutex_unlock(&ftrace_lock);
6084 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6087 trace_create_file("available_filter_functions", 0444,
6088 d_tracer, NULL, &ftrace_avail_fops);
6090 trace_create_file("enabled_functions", 0444,
6091 d_tracer, NULL, &ftrace_enabled_fops);
6093 ftrace_create_filter_files(&global_ops, d_tracer);
6095 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6096 trace_create_file("set_graph_function", 0644, d_tracer,
6098 &ftrace_graph_fops);
6099 trace_create_file("set_graph_notrace", 0644, d_tracer,
6101 &ftrace_graph_notrace_fops);
6102 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6107 static int ftrace_cmp_ips(const void *a, const void *b)
6109 const unsigned long *ipa = a;
6110 const unsigned long *ipb = b;
6119 static int ftrace_process_locs(struct module *mod,
6120 unsigned long *start,
6123 struct ftrace_page *start_pg;
6124 struct ftrace_page *pg;
6125 struct dyn_ftrace *rec;
6126 unsigned long count;
6129 unsigned long flags = 0; /* Shut up gcc */
6132 count = end - start;
6137 sort(start, count, sizeof(*start),
6138 ftrace_cmp_ips, NULL);
6140 start_pg = ftrace_allocate_pages(count);
6144 mutex_lock(&ftrace_lock);
6147 * Core and each module needs their own pages, as
6148 * modules will free them when they are removed.
6149 * Force a new page to be allocated for modules.
6152 WARN_ON(ftrace_pages || ftrace_pages_start);
6153 /* First initialization */
6154 ftrace_pages = ftrace_pages_start = start_pg;
6159 if (WARN_ON(ftrace_pages->next)) {
6160 /* Hmm, we have free pages? */
6161 while (ftrace_pages->next)
6162 ftrace_pages = ftrace_pages->next;
6165 ftrace_pages->next = start_pg;
6171 addr = ftrace_call_adjust(*p++);
6173 * Some architecture linkers will pad between
6174 * the different mcount_loc sections of different
6175 * object files to satisfy alignments.
6176 * Skip any NULL pointers.
6181 if (pg->index == pg->size) {
6182 /* We should have allocated enough */
6183 if (WARN_ON(!pg->next))
6188 rec = &pg->records[pg->index++];
6192 /* We should have used all pages */
6195 /* Assign the last page to ftrace_pages */
6199 * We only need to disable interrupts on start up
6200 * because we are modifying code that an interrupt
6201 * may execute, and the modification is not atomic.
6202 * But for modules, nothing runs the code we modify
6203 * until we are finished with it, and there's no
6204 * reason to cause large interrupt latencies while we do it.
6207 local_irq_save(flags);
6208 ftrace_update_code(mod, start_pg);
6210 local_irq_restore(flags);
6213 mutex_unlock(&ftrace_lock);
6218 struct ftrace_mod_func {
6219 struct list_head list;
6225 struct ftrace_mod_map {
6226 struct rcu_head rcu;
6227 struct list_head list;
6229 unsigned long start_addr;
6230 unsigned long end_addr;
6231 struct list_head funcs;
6232 unsigned int num_funcs;
6235 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6236 unsigned long *value, char *type,
6237 char *name, char *module_name,
6240 struct ftrace_ops *op;
6242 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6243 if (!op->trampoline || symnum--)
6245 *value = op->trampoline;
6247 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6248 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6256 #ifdef CONFIG_MODULES
6258 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6260 static LIST_HEAD(ftrace_mod_maps);
6262 static int referenced_filters(struct dyn_ftrace *rec)
6264 struct ftrace_ops *ops;
6267 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6268 if (ops_references_rec(ops, rec)) {
6269 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6271 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6274 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6275 rec->flags |= FTRACE_FL_REGS;
6276 if (cnt == 1 && ops->trampoline)
6277 rec->flags |= FTRACE_FL_TRAMP;
6279 rec->flags &= ~FTRACE_FL_TRAMP;
6287 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6289 struct ftrace_func_entry *entry;
6290 struct dyn_ftrace *rec;
6293 if (ftrace_hash_empty(hash))
6296 for (i = 0; i < pg->index; i++) {
6297 rec = &pg->records[i];
6298 entry = __ftrace_lookup_ip(hash, rec->ip);
6300 * Do not allow this rec to match again.
6301 * Yeah, it may waste some memory, but will be removed
6302 * if/when the hash is modified again.
6309 /* Clear any records from hashs */
6310 static void clear_mod_from_hashes(struct ftrace_page *pg)
6312 struct trace_array *tr;
6314 mutex_lock(&trace_types_lock);
6315 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6316 if (!tr->ops || !tr->ops->func_hash)
6318 mutex_lock(&tr->ops->func_hash->regex_lock);
6319 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6320 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6321 mutex_unlock(&tr->ops->func_hash->regex_lock);
6323 mutex_unlock(&trace_types_lock);
6326 static void ftrace_free_mod_map(struct rcu_head *rcu)
6328 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6329 struct ftrace_mod_func *mod_func;
6330 struct ftrace_mod_func *n;
6332 /* All the contents of mod_map are now not visible to readers */
6333 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6334 kfree(mod_func->name);
6335 list_del(&mod_func->list);
6342 void ftrace_release_mod(struct module *mod)
6344 struct ftrace_mod_map *mod_map;
6345 struct ftrace_mod_map *n;
6346 struct dyn_ftrace *rec;
6347 struct ftrace_page **last_pg;
6348 struct ftrace_page *tmp_page = NULL;
6349 struct ftrace_page *pg;
6352 mutex_lock(&ftrace_lock);
6354 if (ftrace_disabled)
6357 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6358 if (mod_map->mod == mod) {
6359 list_del_rcu(&mod_map->list);
6360 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6366 * Each module has its own ftrace_pages, remove
6367 * them from the list.
6369 last_pg = &ftrace_pages_start;
6370 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6371 rec = &pg->records[0];
6372 if (within_module_core(rec->ip, mod) ||
6373 within_module_init(rec->ip, mod)) {
6375 * As core pages are first, the first
6376 * page should never be a module page.
6378 if (WARN_ON(pg == ftrace_pages_start))
6381 /* Check if we are deleting the last page */
6382 if (pg == ftrace_pages)
6383 ftrace_pages = next_to_ftrace_page(last_pg);
6385 ftrace_update_tot_cnt -= pg->index;
6386 *last_pg = pg->next;
6388 pg->next = tmp_page;
6391 last_pg = &pg->next;
6394 mutex_unlock(&ftrace_lock);
6396 for (pg = tmp_page; pg; pg = tmp_page) {
6398 /* Needs to be called outside of ftrace_lock */
6399 clear_mod_from_hashes(pg);
6401 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6402 free_pages((unsigned long)pg->records, order);
6403 tmp_page = pg->next;
6405 ftrace_number_of_pages -= 1 << order;
6406 ftrace_number_of_groups--;
6410 void ftrace_module_enable(struct module *mod)
6412 struct dyn_ftrace *rec;
6413 struct ftrace_page *pg;
6415 mutex_lock(&ftrace_lock);
6417 if (ftrace_disabled)
6421 * If the tracing is enabled, go ahead and enable the record.
6423 * The reason not to enable the record immediately is the
6424 * inherent check of ftrace_make_nop/ftrace_make_call for
6425 * correct previous instructions. Making first the NOP
6426 * conversion puts the module to the correct state, thus
6427 * passing the ftrace_make_call check.
6429 * We also delay this to after the module code already set the
6430 * text to read-only, as we now need to set it back to read-write
6431 * so that we can modify the text.
6433 if (ftrace_start_up)
6434 ftrace_arch_code_modify_prepare();
6436 do_for_each_ftrace_rec(pg, rec) {
6439 * do_for_each_ftrace_rec() is a double loop.
6440 * module text shares the pg. If a record is
6441 * not part of this module, then skip this pg,
6442 * which the "break" will do.
6444 if (!within_module_core(rec->ip, mod) &&
6445 !within_module_init(rec->ip, mod))
6451 * When adding a module, we need to check if tracers are
6452 * currently enabled and if they are, and can trace this record,
6453 * we need to enable the module functions as well as update the
6454 * reference counts for those function records.
6456 if (ftrace_start_up)
6457 cnt += referenced_filters(rec);
6459 rec->flags &= ~FTRACE_FL_DISABLED;
6462 if (ftrace_start_up && cnt) {
6463 int failed = __ftrace_replace_code(rec, 1);
6465 ftrace_bug(failed, rec);
6470 } while_for_each_ftrace_rec();
6473 if (ftrace_start_up)
6474 ftrace_arch_code_modify_post_process();
6477 mutex_unlock(&ftrace_lock);
6479 process_cached_mods(mod->name);
6482 void ftrace_module_init(struct module *mod)
6484 if (ftrace_disabled || !mod->num_ftrace_callsites)
6487 ftrace_process_locs(mod, mod->ftrace_callsites,
6488 mod->ftrace_callsites + mod->num_ftrace_callsites);
6491 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6492 struct dyn_ftrace *rec)
6494 struct ftrace_mod_func *mod_func;
6495 unsigned long symsize;
6496 unsigned long offset;
6497 char str[KSYM_SYMBOL_LEN];
6501 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6505 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6509 mod_func->name = kstrdup(str, GFP_KERNEL);
6510 if (!mod_func->name) {
6515 mod_func->ip = rec->ip - offset;
6516 mod_func->size = symsize;
6518 mod_map->num_funcs++;
6520 list_add_rcu(&mod_func->list, &mod_map->funcs);
6523 static struct ftrace_mod_map *
6524 allocate_ftrace_mod_map(struct module *mod,
6525 unsigned long start, unsigned long end)
6527 struct ftrace_mod_map *mod_map;
6529 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6534 mod_map->start_addr = start;
6535 mod_map->end_addr = end;
6536 mod_map->num_funcs = 0;
6538 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6540 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6546 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6547 unsigned long addr, unsigned long *size,
6548 unsigned long *off, char *sym)
6550 struct ftrace_mod_func *found_func = NULL;
6551 struct ftrace_mod_func *mod_func;
6553 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6554 if (addr >= mod_func->ip &&
6555 addr < mod_func->ip + mod_func->size) {
6556 found_func = mod_func;
6563 *size = found_func->size;
6565 *off = addr - found_func->ip;
6567 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6569 return found_func->name;
6576 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6577 unsigned long *off, char **modname, char *sym)
6579 struct ftrace_mod_map *mod_map;
6580 const char *ret = NULL;
6582 /* mod_map is freed via call_rcu() */
6584 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6585 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6588 *modname = mod_map->mod->name;
6597 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6598 char *type, char *name,
6599 char *module_name, int *exported)
6601 struct ftrace_mod_map *mod_map;
6602 struct ftrace_mod_func *mod_func;
6606 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6608 if (symnum >= mod_map->num_funcs) {
6609 symnum -= mod_map->num_funcs;
6613 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6619 *value = mod_func->ip;
6621 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6622 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6630 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6631 module_name, exported);
6637 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6638 struct dyn_ftrace *rec) { }
6639 static inline struct ftrace_mod_map *
6640 allocate_ftrace_mod_map(struct module *mod,
6641 unsigned long start, unsigned long end)
6645 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6646 char *type, char *name, char *module_name,
6652 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6653 module_name, exported);
6657 #endif /* CONFIG_MODULES */
6659 struct ftrace_init_func {
6660 struct list_head list;
6664 /* Clear any init ips from hashes */
6666 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6668 struct ftrace_func_entry *entry;
6670 entry = ftrace_lookup_ip(hash, func->ip);
6672 * Do not allow this rec to match again.
6673 * Yeah, it may waste some memory, but will be removed
6674 * if/when the hash is modified again.
6681 clear_func_from_hashes(struct ftrace_init_func *func)
6683 struct trace_array *tr;
6685 mutex_lock(&trace_types_lock);
6686 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6687 if (!tr->ops || !tr->ops->func_hash)
6689 mutex_lock(&tr->ops->func_hash->regex_lock);
6690 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6691 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6692 mutex_unlock(&tr->ops->func_hash->regex_lock);
6694 mutex_unlock(&trace_types_lock);
6697 static void add_to_clear_hash_list(struct list_head *clear_list,
6698 struct dyn_ftrace *rec)
6700 struct ftrace_init_func *func;
6702 func = kmalloc(sizeof(*func), GFP_KERNEL);
6704 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6709 list_add(&func->list, clear_list);
6712 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6714 unsigned long start = (unsigned long)(start_ptr);
6715 unsigned long end = (unsigned long)(end_ptr);
6716 struct ftrace_page **last_pg = &ftrace_pages_start;
6717 struct ftrace_page *pg;
6718 struct dyn_ftrace *rec;
6719 struct dyn_ftrace key;
6720 struct ftrace_mod_map *mod_map = NULL;
6721 struct ftrace_init_func *func, *func_next;
6722 struct list_head clear_hash;
6725 INIT_LIST_HEAD(&clear_hash);
6728 key.flags = end; /* overload flags, as it is unsigned long */
6730 mutex_lock(&ftrace_lock);
6733 * If we are freeing module init memory, then check if
6734 * any tracer is active. If so, we need to save a mapping of
6735 * the module functions being freed with the address.
6737 if (mod && ftrace_ops_list != &ftrace_list_end)
6738 mod_map = allocate_ftrace_mod_map(mod, start, end);
6740 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6741 if (end < pg->records[0].ip ||
6742 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6745 rec = bsearch(&key, pg->records, pg->index,
6746 sizeof(struct dyn_ftrace),
6751 /* rec will be cleared from hashes after ftrace_lock unlock */
6752 add_to_clear_hash_list(&clear_hash, rec);
6755 save_ftrace_mod_rec(mod_map, rec);
6758 ftrace_update_tot_cnt--;
6760 *last_pg = pg->next;
6761 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6762 free_pages((unsigned long)pg->records, order);
6763 ftrace_number_of_pages -= 1 << order;
6764 ftrace_number_of_groups--;
6766 pg = container_of(last_pg, struct ftrace_page, next);
6771 memmove(rec, rec + 1,
6772 (pg->index - (rec - pg->records)) * sizeof(*rec));
6773 /* More than one function may be in this block */
6776 mutex_unlock(&ftrace_lock);
6778 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6779 clear_func_from_hashes(func);
6784 void __init ftrace_free_init_mem(void)
6786 void *start = (void *)(&__init_begin);
6787 void *end = (void *)(&__init_end);
6789 ftrace_free_mem(NULL, start, end);
6792 void __init ftrace_init(void)
6794 extern unsigned long __start_mcount_loc[];
6795 extern unsigned long __stop_mcount_loc[];
6796 unsigned long count, flags;
6799 local_irq_save(flags);
6800 ret = ftrace_dyn_arch_init();
6801 local_irq_restore(flags);
6805 count = __stop_mcount_loc - __start_mcount_loc;
6807 pr_info("ftrace: No functions to be traced?\n");
6811 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6812 count, count / ENTRIES_PER_PAGE + 1);
6814 last_ftrace_enabled = ftrace_enabled = 1;
6816 ret = ftrace_process_locs(NULL,
6820 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6821 ftrace_number_of_pages, ftrace_number_of_groups);
6823 set_ftrace_early_filters();
6827 ftrace_disabled = 1;
6830 /* Do nothing if arch does not support this */
6831 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6835 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6837 unsigned long trampoline = ops->trampoline;
6839 arch_ftrace_update_trampoline(ops);
6840 if (ops->trampoline && ops->trampoline != trampoline &&
6841 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6842 /* Add to kallsyms before the perf events */
6843 ftrace_add_trampoline_to_kallsyms(ops);
6844 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6845 ops->trampoline, ops->trampoline_size, false,
6846 FTRACE_TRAMPOLINE_SYM);
6848 * Record the perf text poke event after the ksymbol register
6851 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6852 (void *)ops->trampoline,
6853 ops->trampoline_size);
6857 void ftrace_init_trace_array(struct trace_array *tr)
6859 INIT_LIST_HEAD(&tr->func_probes);
6860 INIT_LIST_HEAD(&tr->mod_trace);
6861 INIT_LIST_HEAD(&tr->mod_notrace);
6865 struct ftrace_ops global_ops = {
6866 .func = ftrace_stub,
6867 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6868 FTRACE_OPS_FL_INITIALIZED |
6872 static int __init ftrace_nodyn_init(void)
6877 core_initcall(ftrace_nodyn_init);
6879 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6880 static inline void ftrace_startup_enable(int command) { }
6881 static inline void ftrace_startup_all(int command) { }
6883 # define ftrace_startup_sysctl() do { } while (0)
6884 # define ftrace_shutdown_sysctl() do { } while (0)
6886 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6890 #endif /* CONFIG_DYNAMIC_FTRACE */
6892 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6894 tr->ops = &global_ops;
6895 tr->ops->private = tr;
6896 ftrace_init_trace_array(tr);
6899 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6901 /* If we filter on pids, update to use the pid function */
6902 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6903 if (WARN_ON(tr->ops->func != ftrace_stub))
6904 printk("ftrace ops had %pS for function\n",
6907 tr->ops->func = func;
6908 tr->ops->private = tr;
6911 void ftrace_reset_array_ops(struct trace_array *tr)
6913 tr->ops->func = ftrace_stub;
6916 static nokprobe_inline void
6917 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6918 struct ftrace_ops *ignored, struct pt_regs *regs)
6920 struct ftrace_ops *op;
6923 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6928 * Some of the ops may be dynamically allocated,
6929 * they must be freed after a synchronize_rcu().
6931 preempt_disable_notrace();
6933 do_for_each_ftrace_op(op, ftrace_ops_list) {
6934 /* Stub functions don't need to be called nor tested */
6935 if (op->flags & FTRACE_OPS_FL_STUB)
6938 * Check the following for each ops before calling their func:
6939 * if RCU flag is set, then rcu_is_watching() must be true
6940 * if PER_CPU is set, then ftrace_function_local_disable()
6942 * Otherwise test if the ip matches the ops filter
6944 * If any of the above fails then the op->func() is not executed.
6946 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6947 ftrace_ops_test(op, ip, regs)) {
6948 if (FTRACE_WARN_ON(!op->func)) {
6949 pr_warn("op=%p %pS\n", op, op);
6952 op->func(ip, parent_ip, op, regs);
6954 } while_for_each_ftrace_op(op);
6956 preempt_enable_notrace();
6957 trace_clear_recursion(bit);
6961 * Some archs only support passing ip and parent_ip. Even though
6962 * the list function ignores the op parameter, we do not want any
6963 * C side effects, where a function is called without the caller
6964 * sending a third parameter.
6965 * Archs are to support both the regs and ftrace_ops at the same time.
6966 * If they support ftrace_ops, it is assumed they support regs.
6967 * If call backs want to use regs, they must either check for regs
6968 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6969 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6970 * An architecture can pass partial regs with ftrace_ops and still
6971 * set the ARCH_SUPPORTS_FTRACE_OPS.
6973 #if ARCH_SUPPORTS_FTRACE_OPS
6974 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6975 struct ftrace_ops *op, struct pt_regs *regs)
6977 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6979 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6981 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6983 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6985 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6989 * If there's only one function registered but it does not support
6990 * recursion, needs RCU protection and/or requires per cpu handling, then
6991 * this function will be called by the mcount trampoline.
6993 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6994 struct ftrace_ops *op, struct pt_regs *regs)
6998 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
7002 preempt_disable_notrace();
7004 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7005 op->func(ip, parent_ip, op, regs);
7007 preempt_enable_notrace();
7008 trace_clear_recursion(bit);
7010 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7013 * ftrace_ops_get_func - get the function a trampoline should call
7014 * @ops: the ops to get the function for
7016 * Normally the mcount trampoline will call the ops->func, but there
7017 * are times that it should not. For example, if the ops does not
7018 * have its own recursion protection, then it should call the
7019 * ftrace_ops_assist_func() instead.
7021 * Returns the function that the trampoline should call for @ops.
7023 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7026 * If the function does not handle recursion, needs to be RCU safe,
7027 * or does per cpu logic, then we need to call the assist handler.
7029 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
7030 ops->flags & FTRACE_OPS_FL_RCU)
7031 return ftrace_ops_assist_func;
7037 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7038 struct task_struct *prev, struct task_struct *next)
7040 struct trace_array *tr = data;
7041 struct trace_pid_list *pid_list;
7042 struct trace_pid_list *no_pid_list;
7044 pid_list = rcu_dereference_sched(tr->function_pids);
7045 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7047 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7048 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7051 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7056 ftrace_pid_follow_sched_process_fork(void *data,
7057 struct task_struct *self,
7058 struct task_struct *task)
7060 struct trace_pid_list *pid_list;
7061 struct trace_array *tr = data;
7063 pid_list = rcu_dereference_sched(tr->function_pids);
7064 trace_filter_add_remove_task(pid_list, self, task);
7066 pid_list = rcu_dereference_sched(tr->function_no_pids);
7067 trace_filter_add_remove_task(pid_list, self, task);
7071 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7073 struct trace_pid_list *pid_list;
7074 struct trace_array *tr = data;
7076 pid_list = rcu_dereference_sched(tr->function_pids);
7077 trace_filter_add_remove_task(pid_list, NULL, task);
7079 pid_list = rcu_dereference_sched(tr->function_no_pids);
7080 trace_filter_add_remove_task(pid_list, NULL, task);
7083 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7086 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7088 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7091 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7093 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7098 static void clear_ftrace_pids(struct trace_array *tr, int type)
7100 struct trace_pid_list *pid_list;
7101 struct trace_pid_list *no_pid_list;
7104 pid_list = rcu_dereference_protected(tr->function_pids,
7105 lockdep_is_held(&ftrace_lock));
7106 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7107 lockdep_is_held(&ftrace_lock));
7109 /* Make sure there's something to do */
7110 if (!pid_type_enabled(type, pid_list, no_pid_list))
7113 /* See if the pids still need to be checked after this */
7114 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7115 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7116 for_each_possible_cpu(cpu)
7117 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7120 if (type & TRACE_PIDS)
7121 rcu_assign_pointer(tr->function_pids, NULL);
7123 if (type & TRACE_NO_PIDS)
7124 rcu_assign_pointer(tr->function_no_pids, NULL);
7126 /* Wait till all users are no longer using pid filtering */
7129 if ((type & TRACE_PIDS) && pid_list)
7130 trace_free_pid_list(pid_list);
7132 if ((type & TRACE_NO_PIDS) && no_pid_list)
7133 trace_free_pid_list(no_pid_list);
7136 void ftrace_clear_pids(struct trace_array *tr)
7138 mutex_lock(&ftrace_lock);
7140 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7142 mutex_unlock(&ftrace_lock);
7145 static void ftrace_pid_reset(struct trace_array *tr, int type)
7147 mutex_lock(&ftrace_lock);
7148 clear_ftrace_pids(tr, type);
7150 ftrace_update_pid_func();
7151 ftrace_startup_all(0);
7153 mutex_unlock(&ftrace_lock);
7156 /* Greater than any max PID */
7157 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7159 static void *fpid_start(struct seq_file *m, loff_t *pos)
7162 struct trace_pid_list *pid_list;
7163 struct trace_array *tr = m->private;
7165 mutex_lock(&ftrace_lock);
7166 rcu_read_lock_sched();
7168 pid_list = rcu_dereference_sched(tr->function_pids);
7171 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7173 return trace_pid_start(pid_list, pos);
7176 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7178 struct trace_array *tr = m->private;
7179 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7181 if (v == FTRACE_NO_PIDS) {
7185 return trace_pid_next(pid_list, v, pos);
7188 static void fpid_stop(struct seq_file *m, void *p)
7191 rcu_read_unlock_sched();
7192 mutex_unlock(&ftrace_lock);
7195 static int fpid_show(struct seq_file *m, void *v)
7197 if (v == FTRACE_NO_PIDS) {
7198 seq_puts(m, "no pid\n");
7202 return trace_pid_show(m, v);
7205 static const struct seq_operations ftrace_pid_sops = {
7206 .start = fpid_start,
7212 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7215 struct trace_pid_list *pid_list;
7216 struct trace_array *tr = m->private;
7218 mutex_lock(&ftrace_lock);
7219 rcu_read_lock_sched();
7221 pid_list = rcu_dereference_sched(tr->function_no_pids);
7224 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7226 return trace_pid_start(pid_list, pos);
7229 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7231 struct trace_array *tr = m->private;
7232 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7234 if (v == FTRACE_NO_PIDS) {
7238 return trace_pid_next(pid_list, v, pos);
7241 static const struct seq_operations ftrace_no_pid_sops = {
7242 .start = fnpid_start,
7248 static int pid_open(struct inode *inode, struct file *file, int type)
7250 const struct seq_operations *seq_ops;
7251 struct trace_array *tr = inode->i_private;
7255 ret = tracing_check_open_get_tr(tr);
7259 if ((file->f_mode & FMODE_WRITE) &&
7260 (file->f_flags & O_TRUNC))
7261 ftrace_pid_reset(tr, type);
7265 seq_ops = &ftrace_pid_sops;
7268 seq_ops = &ftrace_no_pid_sops;
7271 trace_array_put(tr);
7276 ret = seq_open(file, seq_ops);
7278 trace_array_put(tr);
7280 m = file->private_data;
7281 /* copy tr over to seq ops */
7289 ftrace_pid_open(struct inode *inode, struct file *file)
7291 return pid_open(inode, file, TRACE_PIDS);
7295 ftrace_no_pid_open(struct inode *inode, struct file *file)
7297 return pid_open(inode, file, TRACE_NO_PIDS);
7300 static void ignore_task_cpu(void *data)
7302 struct trace_array *tr = data;
7303 struct trace_pid_list *pid_list;
7304 struct trace_pid_list *no_pid_list;
7307 * This function is called by on_each_cpu() while the
7308 * event_mutex is held.
7310 pid_list = rcu_dereference_protected(tr->function_pids,
7311 mutex_is_locked(&ftrace_lock));
7312 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7313 mutex_is_locked(&ftrace_lock));
7315 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7316 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7319 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7324 pid_write(struct file *filp, const char __user *ubuf,
7325 size_t cnt, loff_t *ppos, int type)
7327 struct seq_file *m = filp->private_data;
7328 struct trace_array *tr = m->private;
7329 struct trace_pid_list *filtered_pids;
7330 struct trace_pid_list *other_pids;
7331 struct trace_pid_list *pid_list;
7337 mutex_lock(&ftrace_lock);
7341 filtered_pids = rcu_dereference_protected(tr->function_pids,
7342 lockdep_is_held(&ftrace_lock));
7343 other_pids = rcu_dereference_protected(tr->function_no_pids,
7344 lockdep_is_held(&ftrace_lock));
7347 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7348 lockdep_is_held(&ftrace_lock));
7349 other_pids = rcu_dereference_protected(tr->function_pids,
7350 lockdep_is_held(&ftrace_lock));
7358 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7364 rcu_assign_pointer(tr->function_pids, pid_list);
7367 rcu_assign_pointer(tr->function_no_pids, pid_list);
7372 if (filtered_pids) {
7374 trace_free_pid_list(filtered_pids);
7375 } else if (pid_list && !other_pids) {
7376 /* Register a probe to set whether to ignore the tracing of a task */
7377 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7381 * Ignoring of pids is done at task switch. But we have to
7382 * check for those tasks that are currently running.
7383 * Always do this in case a pid was appended or removed.
7385 on_each_cpu(ignore_task_cpu, tr, 1);
7387 ftrace_update_pid_func();
7388 ftrace_startup_all(0);
7390 mutex_unlock(&ftrace_lock);
7399 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7400 size_t cnt, loff_t *ppos)
7402 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7406 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7407 size_t cnt, loff_t *ppos)
7409 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7413 ftrace_pid_release(struct inode *inode, struct file *file)
7415 struct trace_array *tr = inode->i_private;
7417 trace_array_put(tr);
7419 return seq_release(inode, file);
7422 static const struct file_operations ftrace_pid_fops = {
7423 .open = ftrace_pid_open,
7424 .write = ftrace_pid_write,
7426 .llseek = tracing_lseek,
7427 .release = ftrace_pid_release,
7430 static const struct file_operations ftrace_no_pid_fops = {
7431 .open = ftrace_no_pid_open,
7432 .write = ftrace_no_pid_write,
7434 .llseek = tracing_lseek,
7435 .release = ftrace_pid_release,
7438 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7440 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7441 tr, &ftrace_pid_fops);
7442 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7443 tr, &ftrace_no_pid_fops);
7446 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7447 struct dentry *d_tracer)
7449 /* Only the top level directory has the dyn_tracefs and profile */
7450 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7452 ftrace_init_dyn_tracefs(d_tracer);
7453 ftrace_profile_tracefs(d_tracer);
7457 * ftrace_kill - kill ftrace
7459 * This function should be used by panic code. It stops ftrace
7460 * but in a not so nice way. If you need to simply kill ftrace
7461 * from a non-atomic section, use ftrace_kill.
7463 void ftrace_kill(void)
7465 ftrace_disabled = 1;
7467 ftrace_trace_function = ftrace_stub;
7471 * Test if ftrace is dead or not.
7473 int ftrace_is_dead(void)
7475 return ftrace_disabled;
7479 * register_ftrace_function - register a function for profiling
7480 * @ops - ops structure that holds the function for profiling.
7482 * Register a function to be called by all functions in the
7485 * Note: @ops->func and all the functions it calls must be labeled
7486 * with "notrace", otherwise it will go into a
7489 int register_ftrace_function(struct ftrace_ops *ops)
7493 ftrace_ops_init(ops);
7495 mutex_lock(&ftrace_lock);
7497 ret = ftrace_startup(ops, 0);
7499 mutex_unlock(&ftrace_lock);
7503 EXPORT_SYMBOL_GPL(register_ftrace_function);
7506 * unregister_ftrace_function - unregister a function for profiling.
7507 * @ops - ops structure that holds the function to unregister
7509 * Unregister a function that was added to be called by ftrace profiling.
7511 int unregister_ftrace_function(struct ftrace_ops *ops)
7515 mutex_lock(&ftrace_lock);
7516 ret = ftrace_shutdown(ops, 0);
7517 mutex_unlock(&ftrace_lock);
7521 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7523 static bool is_permanent_ops_registered(void)
7525 struct ftrace_ops *op;
7527 do_for_each_ftrace_op(op, ftrace_ops_list) {
7528 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7530 } while_for_each_ftrace_op(op);
7536 ftrace_enable_sysctl(struct ctl_table *table, int write,
7537 void *buffer, size_t *lenp, loff_t *ppos)
7541 mutex_lock(&ftrace_lock);
7543 if (unlikely(ftrace_disabled))
7546 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7548 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7551 if (ftrace_enabled) {
7553 /* we are starting ftrace again */
7554 if (rcu_dereference_protected(ftrace_ops_list,
7555 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7556 update_ftrace_function();
7558 ftrace_startup_sysctl();
7561 if (is_permanent_ops_registered()) {
7562 ftrace_enabled = true;
7567 /* stopping ftrace calls (just send to ftrace_stub) */
7568 ftrace_trace_function = ftrace_stub;
7570 ftrace_shutdown_sysctl();
7573 last_ftrace_enabled = !!ftrace_enabled;
7575 mutex_unlock(&ftrace_lock);