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_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1633 static struct ftrace_ops *
1634 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1636 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1640 struct ftrace_hash *hash;
1641 struct ftrace_hash *other_hash;
1642 struct ftrace_page *pg;
1643 struct dyn_ftrace *rec;
1644 bool update = false;
1648 /* Only update if the ops has been registered */
1649 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1653 * In the filter_hash case:
1654 * If the count is zero, we update all records.
1655 * Otherwise we just update the items in the hash.
1657 * In the notrace_hash case:
1658 * We enable the update in the hash.
1659 * As disabling notrace means enabling the tracing,
1660 * and enabling notrace means disabling, the inc variable
1664 hash = ops->func_hash->filter_hash;
1665 other_hash = ops->func_hash->notrace_hash;
1666 if (ftrace_hash_empty(hash))
1670 hash = ops->func_hash->notrace_hash;
1671 other_hash = ops->func_hash->filter_hash;
1673 * If the notrace hash has no items,
1674 * then there's nothing to do.
1676 if (ftrace_hash_empty(hash))
1680 do_for_each_ftrace_rec(pg, rec) {
1681 int in_other_hash = 0;
1685 if (rec->flags & FTRACE_FL_DISABLED)
1690 * Only the filter_hash affects all records.
1691 * Update if the record is not in the notrace hash.
1693 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1696 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1697 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1700 * If filter_hash is set, we want to match all functions
1701 * that are in the hash but not in the other hash.
1703 * If filter_hash is not set, then we are decrementing.
1704 * That means we match anything that is in the hash
1705 * and also in the other_hash. That is, we need to turn
1706 * off functions in the other hash because they are disabled
1709 if (filter_hash && in_hash && !in_other_hash)
1711 else if (!filter_hash && in_hash &&
1712 (in_other_hash || ftrace_hash_empty(other_hash)))
1720 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1723 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1724 rec->flags |= FTRACE_FL_DIRECT;
1727 * If there's only a single callback registered to a
1728 * function, and the ops has a trampoline registered
1729 * for it, then we can call it directly.
1731 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1732 rec->flags |= FTRACE_FL_TRAMP;
1735 * If we are adding another function callback
1736 * to this function, and the previous had a
1737 * custom trampoline in use, then we need to go
1738 * back to the default trampoline.
1740 rec->flags &= ~FTRACE_FL_TRAMP;
1743 * If any ops wants regs saved for this function
1744 * then all ops will get saved regs.
1746 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1747 rec->flags |= FTRACE_FL_REGS;
1749 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1754 * Only the internal direct_ops should have the
1755 * DIRECT flag set. Thus, if it is removing a
1756 * function, then that function should no longer
1759 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1760 rec->flags &= ~FTRACE_FL_DIRECT;
1763 * If the rec had REGS enabled and the ops that is
1764 * being removed had REGS set, then see if there is
1765 * still any ops for this record that wants regs.
1766 * If not, we can stop recording them.
1768 if (ftrace_rec_count(rec) > 0 &&
1769 rec->flags & FTRACE_FL_REGS &&
1770 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1771 if (!test_rec_ops_needs_regs(rec))
1772 rec->flags &= ~FTRACE_FL_REGS;
1776 * The TRAMP needs to be set only if rec count
1777 * is decremented to one, and the ops that is
1778 * left has a trampoline. As TRAMP can only be
1779 * enabled if there is only a single ops attached
1782 if (ftrace_rec_count(rec) == 1 &&
1783 ftrace_find_tramp_ops_any_other(rec, ops))
1784 rec->flags |= FTRACE_FL_TRAMP;
1786 rec->flags &= ~FTRACE_FL_TRAMP;
1789 * flags will be cleared in ftrace_check_record()
1790 * if rec count is zero.
1795 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1796 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1798 /* Shortcut, if we handled all records, we are done. */
1799 if (!all && count == hash->count)
1801 } while_for_each_ftrace_rec();
1806 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1809 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1812 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1815 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1818 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1819 int filter_hash, int inc)
1821 struct ftrace_ops *op;
1823 __ftrace_hash_rec_update(ops, filter_hash, inc);
1825 if (ops->func_hash != &global_ops.local_hash)
1829 * If the ops shares the global_ops hash, then we need to update
1830 * all ops that are enabled and use this hash.
1832 do_for_each_ftrace_op(op, ftrace_ops_list) {
1836 if (op->func_hash == &global_ops.local_hash)
1837 __ftrace_hash_rec_update(op, filter_hash, inc);
1838 } while_for_each_ftrace_op(op);
1841 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1844 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1847 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1850 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1854 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1855 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1856 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1857 * Note that old_hash and new_hash has below meanings
1858 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1859 * - If the hash is EMPTY_HASH, it hits nothing
1860 * - Anything else hits the recs which match the hash entries.
1862 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1863 struct ftrace_hash *old_hash,
1864 struct ftrace_hash *new_hash)
1866 struct ftrace_page *pg;
1867 struct dyn_ftrace *rec, *end = NULL;
1870 /* Only update if the ops has been registered */
1871 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1874 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1878 * Since the IPMODIFY is a very address sensitive action, we do not
1879 * allow ftrace_ops to set all functions to new hash.
1881 if (!new_hash || !old_hash)
1884 /* Update rec->flags */
1885 do_for_each_ftrace_rec(pg, rec) {
1887 if (rec->flags & FTRACE_FL_DISABLED)
1890 /* We need to update only differences of filter_hash */
1891 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1892 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1893 if (in_old == in_new)
1897 /* New entries must ensure no others are using it */
1898 if (rec->flags & FTRACE_FL_IPMODIFY)
1900 rec->flags |= FTRACE_FL_IPMODIFY;
1901 } else /* Removed entry */
1902 rec->flags &= ~FTRACE_FL_IPMODIFY;
1903 } while_for_each_ftrace_rec();
1910 /* Roll back what we did above */
1911 do_for_each_ftrace_rec(pg, rec) {
1913 if (rec->flags & FTRACE_FL_DISABLED)
1919 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1920 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1921 if (in_old == in_new)
1925 rec->flags &= ~FTRACE_FL_IPMODIFY;
1927 rec->flags |= FTRACE_FL_IPMODIFY;
1928 } while_for_each_ftrace_rec();
1934 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1936 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1938 if (ftrace_hash_empty(hash))
1941 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1944 /* Disabling always succeeds */
1945 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1947 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1949 if (ftrace_hash_empty(hash))
1952 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1955 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1956 struct ftrace_hash *new_hash)
1958 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1960 if (ftrace_hash_empty(old_hash))
1963 if (ftrace_hash_empty(new_hash))
1966 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1969 static void print_ip_ins(const char *fmt, const unsigned char *p)
1973 printk(KERN_CONT "%s", fmt);
1975 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1976 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1979 enum ftrace_bug_type ftrace_bug_type;
1980 const void *ftrace_expected;
1982 static void print_bug_type(void)
1984 switch (ftrace_bug_type) {
1985 case FTRACE_BUG_UNKNOWN:
1987 case FTRACE_BUG_INIT:
1988 pr_info("Initializing ftrace call sites\n");
1990 case FTRACE_BUG_NOP:
1991 pr_info("Setting ftrace call site to NOP\n");
1993 case FTRACE_BUG_CALL:
1994 pr_info("Setting ftrace call site to call ftrace function\n");
1996 case FTRACE_BUG_UPDATE:
1997 pr_info("Updating ftrace call site to call a different ftrace function\n");
2003 * ftrace_bug - report and shutdown function tracer
2004 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2005 * @rec: The record that failed
2007 * The arch code that enables or disables the function tracing
2008 * can call ftrace_bug() when it has detected a problem in
2009 * modifying the code. @failed should be one of either:
2010 * EFAULT - if the problem happens on reading the @ip address
2011 * EINVAL - if what is read at @ip is not what was expected
2012 * EPERM - if the problem happens on writing to the @ip address
2014 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2016 unsigned long ip = rec ? rec->ip : 0;
2018 pr_info("------------[ ftrace bug ]------------\n");
2022 pr_info("ftrace faulted on modifying ");
2023 print_ip_sym(KERN_INFO, ip);
2026 pr_info("ftrace failed to modify ");
2027 print_ip_sym(KERN_INFO, ip);
2028 print_ip_ins(" actual: ", (unsigned char *)ip);
2030 if (ftrace_expected) {
2031 print_ip_ins(" expected: ", ftrace_expected);
2036 pr_info("ftrace faulted on writing ");
2037 print_ip_sym(KERN_INFO, ip);
2040 pr_info("ftrace faulted on unknown error ");
2041 print_ip_sym(KERN_INFO, ip);
2045 struct ftrace_ops *ops = NULL;
2047 pr_info("ftrace record flags: %lx\n", rec->flags);
2048 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2049 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2050 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2051 ops = ftrace_find_tramp_ops_any(rec);
2054 pr_cont("\ttramp: %pS (%pS)",
2055 (void *)ops->trampoline,
2057 ops = ftrace_find_tramp_ops_next(rec, ops);
2060 pr_cont("\ttramp: ERROR!");
2063 ip = ftrace_get_addr_curr(rec);
2064 pr_cont("\n expected tramp: %lx\n", ip);
2067 FTRACE_WARN_ON_ONCE(1);
2070 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2072 unsigned long flag = 0UL;
2074 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2076 if (rec->flags & FTRACE_FL_DISABLED)
2077 return FTRACE_UPDATE_IGNORE;
2080 * If we are updating calls:
2082 * If the record has a ref count, then we need to enable it
2083 * because someone is using it.
2085 * Otherwise we make sure its disabled.
2087 * If we are disabling calls, then disable all records that
2090 if (enable && ftrace_rec_count(rec))
2091 flag = FTRACE_FL_ENABLED;
2094 * If enabling and the REGS flag does not match the REGS_EN, or
2095 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2096 * this record. Set flags to fail the compare against ENABLED.
2097 * Same for direct calls.
2100 if (!(rec->flags & FTRACE_FL_REGS) !=
2101 !(rec->flags & FTRACE_FL_REGS_EN))
2102 flag |= FTRACE_FL_REGS;
2104 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2105 !(rec->flags & FTRACE_FL_TRAMP_EN))
2106 flag |= FTRACE_FL_TRAMP;
2109 * Direct calls are special, as count matters.
2110 * We must test the record for direct, if the
2111 * DIRECT and DIRECT_EN do not match, but only
2112 * if the count is 1. That's because, if the
2113 * count is something other than one, we do not
2114 * want the direct enabled (it will be done via the
2115 * direct helper). But if DIRECT_EN is set, and
2116 * the count is not one, we need to clear it.
2118 if (ftrace_rec_count(rec) == 1) {
2119 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2120 !(rec->flags & FTRACE_FL_DIRECT_EN))
2121 flag |= FTRACE_FL_DIRECT;
2122 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2123 flag |= FTRACE_FL_DIRECT;
2127 /* If the state of this record hasn't changed, then do nothing */
2128 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2129 return FTRACE_UPDATE_IGNORE;
2132 /* Save off if rec is being enabled (for return value) */
2133 flag ^= rec->flags & FTRACE_FL_ENABLED;
2136 rec->flags |= FTRACE_FL_ENABLED;
2137 if (flag & FTRACE_FL_REGS) {
2138 if (rec->flags & FTRACE_FL_REGS)
2139 rec->flags |= FTRACE_FL_REGS_EN;
2141 rec->flags &= ~FTRACE_FL_REGS_EN;
2143 if (flag & FTRACE_FL_TRAMP) {
2144 if (rec->flags & FTRACE_FL_TRAMP)
2145 rec->flags |= FTRACE_FL_TRAMP_EN;
2147 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2149 if (flag & FTRACE_FL_DIRECT) {
2151 * If there's only one user (direct_ops helper)
2152 * then we can call the direct function
2153 * directly (no ftrace trampoline).
2155 if (ftrace_rec_count(rec) == 1) {
2156 if (rec->flags & FTRACE_FL_DIRECT)
2157 rec->flags |= FTRACE_FL_DIRECT_EN;
2159 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2162 * Can only call directly if there's
2163 * only one callback to the function.
2165 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2171 * If this record is being updated from a nop, then
2172 * return UPDATE_MAKE_CALL.
2174 * return UPDATE_MODIFY_CALL to tell the caller to convert
2175 * from the save regs, to a non-save regs function or
2176 * vice versa, or from a trampoline call.
2178 if (flag & FTRACE_FL_ENABLED) {
2179 ftrace_bug_type = FTRACE_BUG_CALL;
2180 return FTRACE_UPDATE_MAKE_CALL;
2183 ftrace_bug_type = FTRACE_BUG_UPDATE;
2184 return FTRACE_UPDATE_MODIFY_CALL;
2188 /* If there's no more users, clear all flags */
2189 if (!ftrace_rec_count(rec))
2193 * Just disable the record, but keep the ops TRAMP
2194 * and REGS states. The _EN flags must be disabled though.
2196 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2197 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2200 ftrace_bug_type = FTRACE_BUG_NOP;
2201 return FTRACE_UPDATE_MAKE_NOP;
2205 * ftrace_update_record, set a record that now is tracing or not
2206 * @rec: the record to update
2207 * @enable: set to true if the record is tracing, false to force disable
2209 * The records that represent all functions that can be traced need
2210 * to be updated when tracing has been enabled.
2212 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2214 return ftrace_check_record(rec, enable, true);
2218 * ftrace_test_record, check if the record has been enabled or not
2219 * @rec: the record to test
2220 * @enable: set to true to check if enabled, false if it is disabled
2222 * The arch code may need to test if a record is already set to
2223 * tracing to determine how to modify the function code that it
2226 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2228 return ftrace_check_record(rec, enable, false);
2231 static struct ftrace_ops *
2232 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2234 struct ftrace_ops *op;
2235 unsigned long ip = rec->ip;
2237 do_for_each_ftrace_op(op, ftrace_ops_list) {
2239 if (!op->trampoline)
2242 if (hash_contains_ip(ip, op->func_hash))
2244 } while_for_each_ftrace_op(op);
2249 static struct ftrace_ops *
2250 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2252 struct ftrace_ops *op;
2253 unsigned long ip = rec->ip;
2255 do_for_each_ftrace_op(op, ftrace_ops_list) {
2257 if (op == op_exclude || !op->trampoline)
2260 if (hash_contains_ip(ip, op->func_hash))
2262 } while_for_each_ftrace_op(op);
2267 static struct ftrace_ops *
2268 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2269 struct ftrace_ops *op)
2271 unsigned long ip = rec->ip;
2273 while_for_each_ftrace_op(op) {
2275 if (!op->trampoline)
2278 if (hash_contains_ip(ip, op->func_hash))
2285 static struct ftrace_ops *
2286 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2288 struct ftrace_ops *op;
2289 unsigned long ip = rec->ip;
2292 * Need to check removed ops first.
2293 * If they are being removed, and this rec has a tramp,
2294 * and this rec is in the ops list, then it would be the
2295 * one with the tramp.
2298 if (hash_contains_ip(ip, &removed_ops->old_hash))
2303 * Need to find the current trampoline for a rec.
2304 * Now, a trampoline is only attached to a rec if there
2305 * was a single 'ops' attached to it. But this can be called
2306 * when we are adding another op to the rec or removing the
2307 * current one. Thus, if the op is being added, we can
2308 * ignore it because it hasn't attached itself to the rec
2311 * If an ops is being modified (hooking to different functions)
2312 * then we don't care about the new functions that are being
2313 * added, just the old ones (that are probably being removed).
2315 * If we are adding an ops to a function that already is using
2316 * a trampoline, it needs to be removed (trampolines are only
2317 * for single ops connected), then an ops that is not being
2318 * modified also needs to be checked.
2320 do_for_each_ftrace_op(op, ftrace_ops_list) {
2322 if (!op->trampoline)
2326 * If the ops is being added, it hasn't gotten to
2327 * the point to be removed from this tree yet.
2329 if (op->flags & FTRACE_OPS_FL_ADDING)
2334 * If the ops is being modified and is in the old
2335 * hash, then it is probably being removed from this
2338 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2339 hash_contains_ip(ip, &op->old_hash))
2342 * If the ops is not being added or modified, and it's
2343 * in its normal filter hash, then this must be the one
2346 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2347 hash_contains_ip(ip, op->func_hash))
2350 } while_for_each_ftrace_op(op);
2355 static struct ftrace_ops *
2356 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2358 struct ftrace_ops *op;
2359 unsigned long ip = rec->ip;
2361 do_for_each_ftrace_op(op, ftrace_ops_list) {
2362 /* pass rec in as regs to have non-NULL val */
2363 if (hash_contains_ip(ip, op->func_hash))
2365 } while_for_each_ftrace_op(op);
2370 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2371 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2372 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2373 static DEFINE_MUTEX(direct_mutex);
2374 int ftrace_direct_func_count;
2377 * Search the direct_functions hash to see if the given instruction pointer
2378 * has a direct caller attached to it.
2380 unsigned long ftrace_find_rec_direct(unsigned long ip)
2382 struct ftrace_func_entry *entry;
2384 entry = __ftrace_lookup_ip(direct_functions, ip);
2388 return entry->direct;
2391 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2392 struct ftrace_ops *ops, struct pt_regs *regs)
2396 addr = ftrace_find_rec_direct(ip);
2400 arch_ftrace_set_direct_caller(regs, addr);
2403 struct ftrace_ops direct_ops = {
2404 .func = call_direct_funcs,
2405 .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
2406 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2407 | FTRACE_OPS_FL_PERMANENT,
2409 * By declaring the main trampoline as this trampoline
2410 * it will never have one allocated for it. Allocated
2411 * trampolines should not call direct functions.
2412 * The direct_ops should only be called by the builtin
2413 * ftrace_regs_caller trampoline.
2415 .trampoline = FTRACE_REGS_ADDR,
2417 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2420 * ftrace_get_addr_new - Get the call address to set to
2421 * @rec: The ftrace record descriptor
2423 * If the record has the FTRACE_FL_REGS set, that means that it
2424 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2425 * is not set, then it wants to convert to the normal callback.
2427 * Returns the address of the trampoline to set to
2429 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2431 struct ftrace_ops *ops;
2434 if ((rec->flags & FTRACE_FL_DIRECT) &&
2435 (ftrace_rec_count(rec) == 1)) {
2436 addr = ftrace_find_rec_direct(rec->ip);
2442 /* Trampolines take precedence over regs */
2443 if (rec->flags & FTRACE_FL_TRAMP) {
2444 ops = ftrace_find_tramp_ops_new(rec);
2445 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2446 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2447 (void *)rec->ip, (void *)rec->ip, rec->flags);
2448 /* Ftrace is shutting down, return anything */
2449 return (unsigned long)FTRACE_ADDR;
2451 return ops->trampoline;
2454 if (rec->flags & FTRACE_FL_REGS)
2455 return (unsigned long)FTRACE_REGS_ADDR;
2457 return (unsigned long)FTRACE_ADDR;
2461 * ftrace_get_addr_curr - Get the call address that is already there
2462 * @rec: The ftrace record descriptor
2464 * The FTRACE_FL_REGS_EN is set when the record already points to
2465 * a function that saves all the regs. Basically the '_EN' version
2466 * represents the current state of the function.
2468 * Returns the address of the trampoline that is currently being called
2470 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2472 struct ftrace_ops *ops;
2475 /* Direct calls take precedence over trampolines */
2476 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2477 addr = ftrace_find_rec_direct(rec->ip);
2483 /* Trampolines take precedence over regs */
2484 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2485 ops = ftrace_find_tramp_ops_curr(rec);
2486 if (FTRACE_WARN_ON(!ops)) {
2487 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2488 (void *)rec->ip, (void *)rec->ip);
2489 /* Ftrace is shutting down, return anything */
2490 return (unsigned long)FTRACE_ADDR;
2492 return ops->trampoline;
2495 if (rec->flags & FTRACE_FL_REGS_EN)
2496 return (unsigned long)FTRACE_REGS_ADDR;
2498 return (unsigned long)FTRACE_ADDR;
2502 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2504 unsigned long ftrace_old_addr;
2505 unsigned long ftrace_addr;
2508 ftrace_addr = ftrace_get_addr_new(rec);
2510 /* This needs to be done before we call ftrace_update_record */
2511 ftrace_old_addr = ftrace_get_addr_curr(rec);
2513 ret = ftrace_update_record(rec, enable);
2515 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2518 case FTRACE_UPDATE_IGNORE:
2521 case FTRACE_UPDATE_MAKE_CALL:
2522 ftrace_bug_type = FTRACE_BUG_CALL;
2523 return ftrace_make_call(rec, ftrace_addr);
2525 case FTRACE_UPDATE_MAKE_NOP:
2526 ftrace_bug_type = FTRACE_BUG_NOP;
2527 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2529 case FTRACE_UPDATE_MODIFY_CALL:
2530 ftrace_bug_type = FTRACE_BUG_UPDATE;
2531 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2534 return -1; /* unknown ftrace bug */
2537 void __weak ftrace_replace_code(int mod_flags)
2539 struct dyn_ftrace *rec;
2540 struct ftrace_page *pg;
2541 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2542 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2545 if (unlikely(ftrace_disabled))
2548 do_for_each_ftrace_rec(pg, rec) {
2550 if (rec->flags & FTRACE_FL_DISABLED)
2553 failed = __ftrace_replace_code(rec, enable);
2555 ftrace_bug(failed, rec);
2556 /* Stop processing */
2561 } while_for_each_ftrace_rec();
2564 struct ftrace_rec_iter {
2565 struct ftrace_page *pg;
2570 * ftrace_rec_iter_start, start up iterating over traced functions
2572 * Returns an iterator handle that is used to iterate over all
2573 * the records that represent address locations where functions
2576 * May return NULL if no records are available.
2578 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2581 * We only use a single iterator.
2582 * Protected by the ftrace_lock mutex.
2584 static struct ftrace_rec_iter ftrace_rec_iter;
2585 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2587 iter->pg = ftrace_pages_start;
2590 /* Could have empty pages */
2591 while (iter->pg && !iter->pg->index)
2592 iter->pg = iter->pg->next;
2601 * ftrace_rec_iter_next, get the next record to process.
2602 * @iter: The handle to the iterator.
2604 * Returns the next iterator after the given iterator @iter.
2606 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2610 if (iter->index >= iter->pg->index) {
2611 iter->pg = iter->pg->next;
2614 /* Could have empty pages */
2615 while (iter->pg && !iter->pg->index)
2616 iter->pg = iter->pg->next;
2626 * ftrace_rec_iter_record, get the record at the iterator location
2627 * @iter: The current iterator location
2629 * Returns the record that the current @iter is at.
2631 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2633 return &iter->pg->records[iter->index];
2637 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2641 if (unlikely(ftrace_disabled))
2644 ret = ftrace_init_nop(mod, rec);
2646 ftrace_bug_type = FTRACE_BUG_INIT;
2647 ftrace_bug(ret, rec);
2654 * archs can override this function if they must do something
2655 * before the modifying code is performed.
2657 int __weak ftrace_arch_code_modify_prepare(void)
2663 * archs can override this function if they must do something
2664 * after the modifying code is performed.
2666 int __weak ftrace_arch_code_modify_post_process(void)
2671 void ftrace_modify_all_code(int command)
2673 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2677 if (command & FTRACE_MAY_SLEEP)
2678 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2681 * If the ftrace_caller calls a ftrace_ops func directly,
2682 * we need to make sure that it only traces functions it
2683 * expects to trace. When doing the switch of functions,
2684 * we need to update to the ftrace_ops_list_func first
2685 * before the transition between old and new calls are set,
2686 * as the ftrace_ops_list_func will check the ops hashes
2687 * to make sure the ops are having the right functions
2691 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2692 if (FTRACE_WARN_ON(err))
2696 if (command & FTRACE_UPDATE_CALLS)
2697 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2698 else if (command & FTRACE_DISABLE_CALLS)
2699 ftrace_replace_code(mod_flags);
2701 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2702 function_trace_op = set_function_trace_op;
2704 /* If irqs are disabled, we are in stop machine */
2705 if (!irqs_disabled())
2706 smp_call_function(ftrace_sync_ipi, NULL, 1);
2707 err = ftrace_update_ftrace_func(ftrace_trace_function);
2708 if (FTRACE_WARN_ON(err))
2712 if (command & FTRACE_START_FUNC_RET)
2713 err = ftrace_enable_ftrace_graph_caller();
2714 else if (command & FTRACE_STOP_FUNC_RET)
2715 err = ftrace_disable_ftrace_graph_caller();
2716 FTRACE_WARN_ON(err);
2719 static int __ftrace_modify_code(void *data)
2721 int *command = data;
2723 ftrace_modify_all_code(*command);
2729 * ftrace_run_stop_machine, go back to the stop machine method
2730 * @command: The command to tell ftrace what to do
2732 * If an arch needs to fall back to the stop machine method, the
2733 * it can call this function.
2735 void ftrace_run_stop_machine(int command)
2737 stop_machine(__ftrace_modify_code, &command, NULL);
2741 * arch_ftrace_update_code, modify the code to trace or not trace
2742 * @command: The command that needs to be done
2744 * Archs can override this function if it does not need to
2745 * run stop_machine() to modify code.
2747 void __weak arch_ftrace_update_code(int command)
2749 ftrace_run_stop_machine(command);
2752 static void ftrace_run_update_code(int command)
2756 ret = ftrace_arch_code_modify_prepare();
2757 FTRACE_WARN_ON(ret);
2762 * By default we use stop_machine() to modify the code.
2763 * But archs can do what ever they want as long as it
2764 * is safe. The stop_machine() is the safest, but also
2765 * produces the most overhead.
2767 arch_ftrace_update_code(command);
2769 ret = ftrace_arch_code_modify_post_process();
2770 FTRACE_WARN_ON(ret);
2773 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2774 struct ftrace_ops_hash *old_hash)
2776 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2777 ops->old_hash.filter_hash = old_hash->filter_hash;
2778 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2779 ftrace_run_update_code(command);
2780 ops->old_hash.filter_hash = NULL;
2781 ops->old_hash.notrace_hash = NULL;
2782 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2785 static ftrace_func_t saved_ftrace_func;
2786 static int ftrace_start_up;
2788 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2792 /* List of trace_ops that have allocated trampolines */
2793 static LIST_HEAD(ftrace_ops_trampoline_list);
2795 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2797 lockdep_assert_held(&ftrace_lock);
2798 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2801 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2803 lockdep_assert_held(&ftrace_lock);
2804 list_del_rcu(&ops->list);
2809 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2810 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2813 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2814 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2816 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2818 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2821 * Record the text poke event before the ksymbol unregister
2824 perf_event_text_poke((void *)ops->trampoline,
2825 (void *)ops->trampoline,
2826 ops->trampoline_size, NULL, 0);
2827 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2828 ops->trampoline, ops->trampoline_size,
2829 true, FTRACE_TRAMPOLINE_SYM);
2830 /* Remove from kallsyms after the perf events */
2831 ftrace_remove_trampoline_from_kallsyms(ops);
2834 arch_ftrace_trampoline_free(ops);
2837 static void ftrace_startup_enable(int command)
2839 if (saved_ftrace_func != ftrace_trace_function) {
2840 saved_ftrace_func = ftrace_trace_function;
2841 command |= FTRACE_UPDATE_TRACE_FUNC;
2844 if (!command || !ftrace_enabled)
2847 ftrace_run_update_code(command);
2850 static void ftrace_startup_all(int command)
2852 update_all_ops = true;
2853 ftrace_startup_enable(command);
2854 update_all_ops = false;
2857 int ftrace_startup(struct ftrace_ops *ops, int command)
2861 if (unlikely(ftrace_disabled))
2864 ret = __register_ftrace_function(ops);
2871 * Note that ftrace probes uses this to start up
2872 * and modify functions it will probe. But we still
2873 * set the ADDING flag for modification, as probes
2874 * do not have trampolines. If they add them in the
2875 * future, then the probes will need to distinguish
2876 * between adding and updating probes.
2878 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2880 ret = ftrace_hash_ipmodify_enable(ops);
2882 /* Rollback registration process */
2883 __unregister_ftrace_function(ops);
2885 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2886 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2887 ftrace_trampoline_free(ops);
2891 if (ftrace_hash_rec_enable(ops, 1))
2892 command |= FTRACE_UPDATE_CALLS;
2894 ftrace_startup_enable(command);
2896 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2901 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2905 if (unlikely(ftrace_disabled))
2908 ret = __unregister_ftrace_function(ops);
2914 * Just warn in case of unbalance, no need to kill ftrace, it's not
2915 * critical but the ftrace_call callers may be never nopped again after
2916 * further ftrace uses.
2918 WARN_ON_ONCE(ftrace_start_up < 0);
2920 /* Disabling ipmodify never fails */
2921 ftrace_hash_ipmodify_disable(ops);
2923 if (ftrace_hash_rec_disable(ops, 1))
2924 command |= FTRACE_UPDATE_CALLS;
2926 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2928 if (saved_ftrace_func != ftrace_trace_function) {
2929 saved_ftrace_func = ftrace_trace_function;
2930 command |= FTRACE_UPDATE_TRACE_FUNC;
2933 if (!command || !ftrace_enabled) {
2935 * If these are dynamic or per_cpu ops, they still
2936 * need their data freed. Since, function tracing is
2937 * not currently active, we can just free them
2938 * without synchronizing all CPUs.
2940 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2947 * If the ops uses a trampoline, then it needs to be
2948 * tested first on update.
2950 ops->flags |= FTRACE_OPS_FL_REMOVING;
2953 /* The trampoline logic checks the old hashes */
2954 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2955 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2957 ftrace_run_update_code(command);
2960 * If there's no more ops registered with ftrace, run a
2961 * sanity check to make sure all rec flags are cleared.
2963 if (rcu_dereference_protected(ftrace_ops_list,
2964 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2965 struct ftrace_page *pg;
2966 struct dyn_ftrace *rec;
2968 do_for_each_ftrace_rec(pg, rec) {
2969 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2970 pr_warn(" %pS flags:%lx\n",
2971 (void *)rec->ip, rec->flags);
2972 } while_for_each_ftrace_rec();
2975 ops->old_hash.filter_hash = NULL;
2976 ops->old_hash.notrace_hash = NULL;
2979 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2982 * Dynamic ops may be freed, we must make sure that all
2983 * callers are done before leaving this function.
2984 * The same goes for freeing the per_cpu data of the per_cpu
2987 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2989 * We need to do a hard force of sched synchronization.
2990 * This is because we use preempt_disable() to do RCU, but
2991 * the function tracers can be called where RCU is not watching
2992 * (like before user_exit()). We can not rely on the RCU
2993 * infrastructure to do the synchronization, thus we must do it
2996 synchronize_rcu_tasks_rude();
2999 * When the kernel is preemptive, tasks can be preempted
3000 * while on a ftrace trampoline. Just scheduling a task on
3001 * a CPU is not good enough to flush them. Calling
3002 * synchornize_rcu_tasks() will wait for those tasks to
3003 * execute and either schedule voluntarily or enter user space.
3005 if (IS_ENABLED(CONFIG_PREEMPTION))
3006 synchronize_rcu_tasks();
3009 ftrace_trampoline_free(ops);
3015 static void ftrace_startup_sysctl(void)
3019 if (unlikely(ftrace_disabled))
3022 /* Force update next time */
3023 saved_ftrace_func = NULL;
3024 /* ftrace_start_up is true if we want ftrace running */
3025 if (ftrace_start_up) {
3026 command = FTRACE_UPDATE_CALLS;
3027 if (ftrace_graph_active)
3028 command |= FTRACE_START_FUNC_RET;
3029 ftrace_startup_enable(command);
3033 static void ftrace_shutdown_sysctl(void)
3037 if (unlikely(ftrace_disabled))
3040 /* ftrace_start_up is true if ftrace is running */
3041 if (ftrace_start_up) {
3042 command = FTRACE_DISABLE_CALLS;
3043 if (ftrace_graph_active)
3044 command |= FTRACE_STOP_FUNC_RET;
3045 ftrace_run_update_code(command);
3049 static u64 ftrace_update_time;
3050 unsigned long ftrace_update_tot_cnt;
3051 unsigned long ftrace_number_of_pages;
3052 unsigned long ftrace_number_of_groups;
3054 static inline int ops_traces_mod(struct ftrace_ops *ops)
3057 * Filter_hash being empty will default to trace module.
3058 * But notrace hash requires a test of individual module functions.
3060 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3061 ftrace_hash_empty(ops->func_hash->notrace_hash);
3065 * Check if the current ops references the record.
3067 * If the ops traces all functions, then it was already accounted for.
3068 * If the ops does not trace the current record function, skip it.
3069 * If the ops ignores the function via notrace filter, skip it.
3072 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3074 /* If ops isn't enabled, ignore it */
3075 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3078 /* If ops traces all then it includes this function */
3079 if (ops_traces_mod(ops))
3082 /* The function must be in the filter */
3083 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3084 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3087 /* If in notrace hash, we ignore it too */
3088 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3094 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3096 struct ftrace_page *pg;
3097 struct dyn_ftrace *p;
3099 unsigned long update_cnt = 0;
3100 unsigned long rec_flags = 0;
3103 start = ftrace_now(raw_smp_processor_id());
3106 * When a module is loaded, this function is called to convert
3107 * the calls to mcount in its text to nops, and also to create
3108 * an entry in the ftrace data. Now, if ftrace is activated
3109 * after this call, but before the module sets its text to
3110 * read-only, the modification of enabling ftrace can fail if
3111 * the read-only is done while ftrace is converting the calls.
3112 * To prevent this, the module's records are set as disabled
3113 * and will be enabled after the call to set the module's text
3117 rec_flags |= FTRACE_FL_DISABLED;
3119 for (pg = new_pgs; pg; pg = pg->next) {
3121 for (i = 0; i < pg->index; i++) {
3123 /* If something went wrong, bail without enabling anything */
3124 if (unlikely(ftrace_disabled))
3127 p = &pg->records[i];
3128 p->flags = rec_flags;
3131 * Do the initial record conversion from mcount jump
3132 * to the NOP instructions.
3134 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3135 !ftrace_nop_initialize(mod, p))
3142 stop = ftrace_now(raw_smp_processor_id());
3143 ftrace_update_time = stop - start;
3144 ftrace_update_tot_cnt += update_cnt;
3149 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3155 if (WARN_ON(!count))
3158 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3159 order = get_count_order(pages);
3162 * We want to fill as much as possible. No more than a page
3165 if (!is_power_of_2(pages))
3169 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3172 /* if we can't allocate this size, try something smaller */
3179 ftrace_number_of_pages += 1 << order;
3180 ftrace_number_of_groups++;
3182 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3191 static struct ftrace_page *
3192 ftrace_allocate_pages(unsigned long num_to_init)
3194 struct ftrace_page *start_pg;
3195 struct ftrace_page *pg;
3202 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3207 * Try to allocate as much as possible in one continues
3208 * location that fills in all of the space. We want to
3209 * waste as little space as possible.
3212 cnt = ftrace_allocate_records(pg, num_to_init);
3220 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3232 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3233 free_pages((unsigned long)pg->records, order);
3234 start_pg = pg->next;
3237 ftrace_number_of_pages -= 1 << order;
3238 ftrace_number_of_groups--;
3240 pr_info("ftrace: FAILED to allocate memory for functions\n");
3244 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3246 struct ftrace_iterator {
3250 struct ftrace_page *pg;
3251 struct dyn_ftrace *func;
3252 struct ftrace_func_probe *probe;
3253 struct ftrace_func_entry *probe_entry;
3254 struct trace_parser parser;
3255 struct ftrace_hash *hash;
3256 struct ftrace_ops *ops;
3257 struct trace_array *tr;
3258 struct list_head *mod_list;
3265 t_probe_next(struct seq_file *m, loff_t *pos)
3267 struct ftrace_iterator *iter = m->private;
3268 struct trace_array *tr = iter->ops->private;
3269 struct list_head *func_probes;
3270 struct ftrace_hash *hash;
3271 struct list_head *next;
3272 struct hlist_node *hnd = NULL;
3273 struct hlist_head *hhd;
3282 func_probes = &tr->func_probes;
3283 if (list_empty(func_probes))
3287 next = func_probes->next;
3288 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3291 if (iter->probe_entry)
3292 hnd = &iter->probe_entry->hlist;
3294 hash = iter->probe->ops.func_hash->filter_hash;
3297 * A probe being registered may temporarily have an empty hash
3298 * and it's at the end of the func_probes list.
3300 if (!hash || hash == EMPTY_HASH)
3303 size = 1 << hash->size_bits;
3306 if (iter->pidx >= size) {
3307 if (iter->probe->list.next == func_probes)
3309 next = iter->probe->list.next;
3310 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3311 hash = iter->probe->ops.func_hash->filter_hash;
3312 size = 1 << hash->size_bits;
3316 hhd = &hash->buckets[iter->pidx];
3318 if (hlist_empty(hhd)) {
3334 if (WARN_ON_ONCE(!hnd))
3337 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3342 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3344 struct ftrace_iterator *iter = m->private;
3348 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3351 if (iter->mod_pos > *pos)
3355 iter->probe_entry = NULL;
3357 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3358 p = t_probe_next(m, &l);
3365 /* Only set this if we have an item */
3366 iter->flags |= FTRACE_ITER_PROBE;
3372 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3374 struct ftrace_func_entry *probe_entry;
3375 struct ftrace_probe_ops *probe_ops;
3376 struct ftrace_func_probe *probe;
3378 probe = iter->probe;
3379 probe_entry = iter->probe_entry;
3381 if (WARN_ON_ONCE(!probe || !probe_entry))
3384 probe_ops = probe->probe_ops;
3386 if (probe_ops->print)
3387 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3389 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3390 (void *)probe_ops->func);
3396 t_mod_next(struct seq_file *m, loff_t *pos)
3398 struct ftrace_iterator *iter = m->private;
3399 struct trace_array *tr = iter->tr;
3404 iter->mod_list = iter->mod_list->next;
3406 if (iter->mod_list == &tr->mod_trace ||
3407 iter->mod_list == &tr->mod_notrace) {
3408 iter->flags &= ~FTRACE_ITER_MOD;
3412 iter->mod_pos = *pos;
3417 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3419 struct ftrace_iterator *iter = m->private;
3423 if (iter->func_pos > *pos)
3426 iter->mod_pos = iter->func_pos;
3428 /* probes are only available if tr is set */
3432 for (l = 0; l <= (*pos - iter->func_pos); ) {
3433 p = t_mod_next(m, &l);
3438 iter->flags &= ~FTRACE_ITER_MOD;
3439 return t_probe_start(m, pos);
3442 /* Only set this if we have an item */
3443 iter->flags |= FTRACE_ITER_MOD;
3449 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3451 struct ftrace_mod_load *ftrace_mod;
3452 struct trace_array *tr = iter->tr;
3454 if (WARN_ON_ONCE(!iter->mod_list) ||
3455 iter->mod_list == &tr->mod_trace ||
3456 iter->mod_list == &tr->mod_notrace)
3459 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3461 if (ftrace_mod->func)
3462 seq_printf(m, "%s", ftrace_mod->func);
3466 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3472 t_func_next(struct seq_file *m, loff_t *pos)
3474 struct ftrace_iterator *iter = m->private;
3475 struct dyn_ftrace *rec = NULL;
3480 if (iter->idx >= iter->pg->index) {
3481 if (iter->pg->next) {
3482 iter->pg = iter->pg->next;
3487 rec = &iter->pg->records[iter->idx++];
3488 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3489 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3491 ((iter->flags & FTRACE_ITER_ENABLED) &&
3492 !(rec->flags & FTRACE_FL_ENABLED))) {
3502 iter->pos = iter->func_pos = *pos;
3509 t_next(struct seq_file *m, void *v, loff_t *pos)
3511 struct ftrace_iterator *iter = m->private;
3512 loff_t l = *pos; /* t_probe_start() must use original pos */
3515 if (unlikely(ftrace_disabled))
3518 if (iter->flags & FTRACE_ITER_PROBE)
3519 return t_probe_next(m, pos);
3521 if (iter->flags & FTRACE_ITER_MOD)
3522 return t_mod_next(m, pos);
3524 if (iter->flags & FTRACE_ITER_PRINTALL) {
3525 /* next must increment pos, and t_probe_start does not */
3527 return t_mod_start(m, &l);
3530 ret = t_func_next(m, pos);
3533 return t_mod_start(m, &l);
3538 static void reset_iter_read(struct ftrace_iterator *iter)
3542 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3545 static void *t_start(struct seq_file *m, loff_t *pos)
3547 struct ftrace_iterator *iter = m->private;
3551 mutex_lock(&ftrace_lock);
3553 if (unlikely(ftrace_disabled))
3557 * If an lseek was done, then reset and start from beginning.
3559 if (*pos < iter->pos)
3560 reset_iter_read(iter);
3563 * For set_ftrace_filter reading, if we have the filter
3564 * off, we can short cut and just print out that all
3565 * functions are enabled.
3567 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3568 ftrace_hash_empty(iter->hash)) {
3569 iter->func_pos = 1; /* Account for the message */
3571 return t_mod_start(m, pos);
3572 iter->flags |= FTRACE_ITER_PRINTALL;
3573 /* reset in case of seek/pread */
3574 iter->flags &= ~FTRACE_ITER_PROBE;
3578 if (iter->flags & FTRACE_ITER_MOD)
3579 return t_mod_start(m, pos);
3582 * Unfortunately, we need to restart at ftrace_pages_start
3583 * every time we let go of the ftrace_mutex. This is because
3584 * those pointers can change without the lock.
3586 iter->pg = ftrace_pages_start;
3588 for (l = 0; l <= *pos; ) {
3589 p = t_func_next(m, &l);
3595 return t_mod_start(m, pos);
3600 static void t_stop(struct seq_file *m, void *p)
3602 mutex_unlock(&ftrace_lock);
3606 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3611 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3612 struct dyn_ftrace *rec)
3616 ptr = arch_ftrace_trampoline_func(ops, rec);
3618 seq_printf(m, " ->%pS", ptr);
3621 static int t_show(struct seq_file *m, void *v)
3623 struct ftrace_iterator *iter = m->private;
3624 struct dyn_ftrace *rec;
3626 if (iter->flags & FTRACE_ITER_PROBE)
3627 return t_probe_show(m, iter);
3629 if (iter->flags & FTRACE_ITER_MOD)
3630 return t_mod_show(m, iter);
3632 if (iter->flags & FTRACE_ITER_PRINTALL) {
3633 if (iter->flags & FTRACE_ITER_NOTRACE)
3634 seq_puts(m, "#### no functions disabled ####\n");
3636 seq_puts(m, "#### all functions enabled ####\n");
3645 seq_printf(m, "%ps", (void *)rec->ip);
3646 if (iter->flags & FTRACE_ITER_ENABLED) {
3647 struct ftrace_ops *ops;
3649 seq_printf(m, " (%ld)%s%s%s",
3650 ftrace_rec_count(rec),
3651 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3652 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3653 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3654 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3655 ops = ftrace_find_tramp_ops_any(rec);
3658 seq_printf(m, "\ttramp: %pS (%pS)",
3659 (void *)ops->trampoline,
3661 add_trampoline_func(m, ops, rec);
3662 ops = ftrace_find_tramp_ops_next(rec, ops);
3665 seq_puts(m, "\ttramp: ERROR!");
3667 add_trampoline_func(m, NULL, rec);
3669 if (rec->flags & FTRACE_FL_DIRECT) {
3670 unsigned long direct;
3672 direct = ftrace_find_rec_direct(rec->ip);
3674 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3683 static const struct seq_operations show_ftrace_seq_ops = {
3691 ftrace_avail_open(struct inode *inode, struct file *file)
3693 struct ftrace_iterator *iter;
3696 ret = security_locked_down(LOCKDOWN_TRACEFS);
3700 if (unlikely(ftrace_disabled))
3703 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3707 iter->pg = ftrace_pages_start;
3708 iter->ops = &global_ops;
3714 ftrace_enabled_open(struct inode *inode, struct file *file)
3716 struct ftrace_iterator *iter;
3719 * This shows us what functions are currently being
3720 * traced and by what. Not sure if we want lockdown
3721 * to hide such critical information for an admin.
3722 * Although, perhaps it can show information we don't
3723 * want people to see, but if something is tracing
3724 * something, we probably want to know about it.
3727 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3731 iter->pg = ftrace_pages_start;
3732 iter->flags = FTRACE_ITER_ENABLED;
3733 iter->ops = &global_ops;
3739 * ftrace_regex_open - initialize function tracer filter files
3740 * @ops: The ftrace_ops that hold the hash filters
3741 * @flag: The type of filter to process
3742 * @inode: The inode, usually passed in to your open routine
3743 * @file: The file, usually passed in to your open routine
3745 * ftrace_regex_open() initializes the filter files for the
3746 * @ops. Depending on @flag it may process the filter hash or
3747 * the notrace hash of @ops. With this called from the open
3748 * routine, you can use ftrace_filter_write() for the write
3749 * routine if @flag has FTRACE_ITER_FILTER set, or
3750 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3751 * tracing_lseek() should be used as the lseek routine, and
3752 * release must call ftrace_regex_release().
3755 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3756 struct inode *inode, struct file *file)
3758 struct ftrace_iterator *iter;
3759 struct ftrace_hash *hash;
3760 struct list_head *mod_head;
3761 struct trace_array *tr = ops->private;
3764 ftrace_ops_init(ops);
3766 if (unlikely(ftrace_disabled))
3769 if (tracing_check_open_get_tr(tr))
3772 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3776 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3783 mutex_lock(&ops->func_hash->regex_lock);
3785 if (flag & FTRACE_ITER_NOTRACE) {
3786 hash = ops->func_hash->notrace_hash;
3787 mod_head = tr ? &tr->mod_notrace : NULL;
3789 hash = ops->func_hash->filter_hash;
3790 mod_head = tr ? &tr->mod_trace : NULL;
3793 iter->mod_list = mod_head;
3795 if (file->f_mode & FMODE_WRITE) {
3796 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3798 if (file->f_flags & O_TRUNC) {
3799 iter->hash = alloc_ftrace_hash(size_bits);
3800 clear_ftrace_mod_list(mod_head);
3802 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3806 trace_parser_put(&iter->parser);
3814 if (file->f_mode & FMODE_READ) {
3815 iter->pg = ftrace_pages_start;
3817 ret = seq_open(file, &show_ftrace_seq_ops);
3819 struct seq_file *m = file->private_data;
3823 free_ftrace_hash(iter->hash);
3824 trace_parser_put(&iter->parser);
3827 file->private_data = iter;
3830 mutex_unlock(&ops->func_hash->regex_lock);
3836 trace_array_put(tr);
3843 ftrace_filter_open(struct inode *inode, struct file *file)
3845 struct ftrace_ops *ops = inode->i_private;
3847 /* Checks for tracefs lockdown */
3848 return ftrace_regex_open(ops,
3849 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3854 ftrace_notrace_open(struct inode *inode, struct file *file)
3856 struct ftrace_ops *ops = inode->i_private;
3858 /* Checks for tracefs lockdown */
3859 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3863 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3864 struct ftrace_glob {
3871 * If symbols in an architecture don't correspond exactly to the user-visible
3872 * name of what they represent, it is possible to define this function to
3873 * perform the necessary adjustments.
3875 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3880 static int ftrace_match(char *str, struct ftrace_glob *g)
3885 str = arch_ftrace_match_adjust(str, g->search);
3889 if (strcmp(str, g->search) == 0)
3892 case MATCH_FRONT_ONLY:
3893 if (strncmp(str, g->search, g->len) == 0)
3896 case MATCH_MIDDLE_ONLY:
3897 if (strstr(str, g->search))
3900 case MATCH_END_ONLY:
3902 if (slen >= g->len &&
3903 memcmp(str + slen - g->len, g->search, g->len) == 0)
3907 if (glob_match(g->search, str))
3916 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3918 struct ftrace_func_entry *entry;
3921 entry = ftrace_lookup_ip(hash, rec->ip);
3923 /* Do nothing if it doesn't exist */
3927 free_hash_entry(hash, entry);
3929 /* Do nothing if it exists */
3933 ret = add_hash_entry(hash, rec->ip);
3939 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3942 long index = simple_strtoul(func_g->search, NULL, 0);
3943 struct ftrace_page *pg;
3944 struct dyn_ftrace *rec;
3946 /* The index starts at 1 */
3950 do_for_each_ftrace_rec(pg, rec) {
3951 if (pg->index <= index) {
3953 /* this is a double loop, break goes to the next page */
3956 rec = &pg->records[index];
3957 enter_record(hash, rec, clear_filter);
3959 } while_for_each_ftrace_rec();
3964 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3965 struct ftrace_glob *mod_g, int exclude_mod)
3967 char str[KSYM_SYMBOL_LEN];
3970 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3973 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3975 /* blank module name to match all modules */
3977 /* blank module globbing: modname xor exclude_mod */
3978 if (!exclude_mod != !modname)
3984 * exclude_mod is set to trace everything but the given
3985 * module. If it is set and the module matches, then
3986 * return 0. If it is not set, and the module doesn't match
3987 * also return 0. Otherwise, check the function to see if
3990 if (!mod_matches == !exclude_mod)
3993 /* blank search means to match all funcs in the mod */
3998 return ftrace_match(str, func_g);
4002 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4004 struct ftrace_page *pg;
4005 struct dyn_ftrace *rec;
4006 struct ftrace_glob func_g = { .type = MATCH_FULL };
4007 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4008 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4009 int exclude_mod = 0;
4012 int clear_filter = 0;
4015 func_g.type = filter_parse_regex(func, len, &func_g.search,
4017 func_g.len = strlen(func_g.search);
4021 mod_g.type = filter_parse_regex(mod, strlen(mod),
4022 &mod_g.search, &exclude_mod);
4023 mod_g.len = strlen(mod_g.search);
4026 mutex_lock(&ftrace_lock);
4028 if (unlikely(ftrace_disabled))
4031 if (func_g.type == MATCH_INDEX) {
4032 found = add_rec_by_index(hash, &func_g, clear_filter);
4036 do_for_each_ftrace_rec(pg, rec) {
4038 if (rec->flags & FTRACE_FL_DISABLED)
4041 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4042 ret = enter_record(hash, rec, clear_filter);
4049 } while_for_each_ftrace_rec();
4051 mutex_unlock(&ftrace_lock);
4057 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4059 return match_records(hash, buff, len, NULL);
4062 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4063 struct ftrace_ops_hash *old_hash)
4065 struct ftrace_ops *op;
4067 if (!ftrace_enabled)
4070 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4071 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4076 * If this is the shared global_ops filter, then we need to
4077 * check if there is another ops that shares it, is enabled.
4078 * If so, we still need to run the modify code.
4080 if (ops->func_hash != &global_ops.local_hash)
4083 do_for_each_ftrace_op(op, ftrace_ops_list) {
4084 if (op->func_hash == &global_ops.local_hash &&
4085 op->flags & FTRACE_OPS_FL_ENABLED) {
4086 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4087 /* Only need to do this once */
4090 } while_for_each_ftrace_op(op);
4093 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4094 struct ftrace_hash **orig_hash,
4095 struct ftrace_hash *hash,
4098 struct ftrace_ops_hash old_hash_ops;
4099 struct ftrace_hash *old_hash;
4102 old_hash = *orig_hash;
4103 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4104 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4105 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4107 ftrace_ops_update_code(ops, &old_hash_ops);
4108 free_ftrace_hash_rcu(old_hash);
4113 static bool module_exists(const char *module)
4115 /* All modules have the symbol __this_module */
4116 static const char this_mod[] = "__this_module";
4117 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4121 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4123 if (n > sizeof(modname) - 1)
4126 val = module_kallsyms_lookup_name(modname);
4130 static int cache_mod(struct trace_array *tr,
4131 const char *func, char *module, int enable)
4133 struct ftrace_mod_load *ftrace_mod, *n;
4134 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4137 mutex_lock(&ftrace_lock);
4139 /* We do not cache inverse filters */
4140 if (func[0] == '!') {
4144 /* Look to remove this hash */
4145 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4146 if (strcmp(ftrace_mod->module, module) != 0)
4149 /* no func matches all */
4150 if (strcmp(func, "*") == 0 ||
4151 (ftrace_mod->func &&
4152 strcmp(ftrace_mod->func, func) == 0)) {
4154 free_ftrace_mod(ftrace_mod);
4162 /* We only care about modules that have not been loaded yet */
4163 if (module_exists(module))
4166 /* Save this string off, and execute it when the module is loaded */
4167 ret = ftrace_add_mod(tr, func, module, enable);
4169 mutex_unlock(&ftrace_lock);
4175 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4176 int reset, int enable);
4178 #ifdef CONFIG_MODULES
4179 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4180 char *mod, bool enable)
4182 struct ftrace_mod_load *ftrace_mod, *n;
4183 struct ftrace_hash **orig_hash, *new_hash;
4184 LIST_HEAD(process_mods);
4188 mutex_lock(&ops->func_hash->regex_lock);
4191 orig_hash = &ops->func_hash->filter_hash;
4193 orig_hash = &ops->func_hash->notrace_hash;
4195 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4198 goto out; /* warn? */
4200 mutex_lock(&ftrace_lock);
4202 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4204 if (strcmp(ftrace_mod->module, mod) != 0)
4207 if (ftrace_mod->func)
4208 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4210 func = kstrdup("*", GFP_KERNEL);
4212 if (!func) /* warn? */
4215 list_del(&ftrace_mod->list);
4216 list_add(&ftrace_mod->list, &process_mods);
4218 /* Use the newly allocated func, as it may be "*" */
4219 kfree(ftrace_mod->func);
4220 ftrace_mod->func = func;
4223 mutex_unlock(&ftrace_lock);
4225 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4227 func = ftrace_mod->func;
4229 /* Grabs ftrace_lock, which is why we have this extra step */
4230 match_records(new_hash, func, strlen(func), mod);
4231 free_ftrace_mod(ftrace_mod);
4234 if (enable && list_empty(head))
4235 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4237 mutex_lock(&ftrace_lock);
4239 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4241 mutex_unlock(&ftrace_lock);
4244 mutex_unlock(&ops->func_hash->regex_lock);
4246 free_ftrace_hash(new_hash);
4249 static void process_cached_mods(const char *mod_name)
4251 struct trace_array *tr;
4254 mod = kstrdup(mod_name, GFP_KERNEL);
4258 mutex_lock(&trace_types_lock);
4259 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4260 if (!list_empty(&tr->mod_trace))
4261 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4262 if (!list_empty(&tr->mod_notrace))
4263 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4265 mutex_unlock(&trace_types_lock);
4272 * We register the module command as a template to show others how
4273 * to register the a command as well.
4277 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4278 char *func_orig, char *cmd, char *module, int enable)
4283 /* match_records() modifies func, and we need the original */
4284 func = kstrdup(func_orig, GFP_KERNEL);
4289 * cmd == 'mod' because we only registered this func
4290 * for the 'mod' ftrace_func_command.
4291 * But if you register one func with multiple commands,
4292 * you can tell which command was used by the cmd
4295 ret = match_records(hash, func, strlen(func), module);
4299 return cache_mod(tr, func_orig, module, enable);
4305 static struct ftrace_func_command ftrace_mod_cmd = {
4307 .func = ftrace_mod_callback,
4310 static int __init ftrace_mod_cmd_init(void)
4312 return register_ftrace_command(&ftrace_mod_cmd);
4314 core_initcall(ftrace_mod_cmd_init);
4316 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4317 struct ftrace_ops *op, struct pt_regs *pt_regs)
4319 struct ftrace_probe_ops *probe_ops;
4320 struct ftrace_func_probe *probe;
4322 probe = container_of(op, struct ftrace_func_probe, ops);
4323 probe_ops = probe->probe_ops;
4326 * Disable preemption for these calls to prevent a RCU grace
4327 * period. This syncs the hash iteration and freeing of items
4328 * on the hash. rcu_read_lock is too dangerous here.
4330 preempt_disable_notrace();
4331 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4332 preempt_enable_notrace();
4335 struct ftrace_func_map {
4336 struct ftrace_func_entry entry;
4340 struct ftrace_func_mapper {
4341 struct ftrace_hash hash;
4345 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4347 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4349 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4351 struct ftrace_hash *hash;
4354 * The mapper is simply a ftrace_hash, but since the entries
4355 * in the hash are not ftrace_func_entry type, we define it
4356 * as a separate structure.
4358 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4359 return (struct ftrace_func_mapper *)hash;
4363 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4364 * @mapper: The mapper that has the ip maps
4365 * @ip: the instruction pointer to find the data for
4367 * Returns the data mapped to @ip if found otherwise NULL. The return
4368 * is actually the address of the mapper data pointer. The address is
4369 * returned for use cases where the data is no bigger than a long, and
4370 * the user can use the data pointer as its data instead of having to
4371 * allocate more memory for the reference.
4373 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4376 struct ftrace_func_entry *entry;
4377 struct ftrace_func_map *map;
4379 entry = ftrace_lookup_ip(&mapper->hash, ip);
4383 map = (struct ftrace_func_map *)entry;
4388 * ftrace_func_mapper_add_ip - Map some data to an ip
4389 * @mapper: The mapper that has the ip maps
4390 * @ip: The instruction pointer address to map @data to
4391 * @data: The data to map to @ip
4393 * Returns 0 on success otherwise an error.
4395 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4396 unsigned long ip, void *data)
4398 struct ftrace_func_entry *entry;
4399 struct ftrace_func_map *map;
4401 entry = ftrace_lookup_ip(&mapper->hash, ip);
4405 map = kmalloc(sizeof(*map), GFP_KERNEL);
4412 __add_hash_entry(&mapper->hash, &map->entry);
4418 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4419 * @mapper: The mapper that has the ip maps
4420 * @ip: The instruction pointer address to remove the data from
4422 * Returns the data if it is found, otherwise NULL.
4423 * Note, if the data pointer is used as the data itself, (see
4424 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4425 * if the data pointer was set to zero.
4427 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4430 struct ftrace_func_entry *entry;
4431 struct ftrace_func_map *map;
4434 entry = ftrace_lookup_ip(&mapper->hash, ip);
4438 map = (struct ftrace_func_map *)entry;
4441 remove_hash_entry(&mapper->hash, entry);
4448 * free_ftrace_func_mapper - free a mapping of ips and data
4449 * @mapper: The mapper that has the ip maps
4450 * @free_func: A function to be called on each data item.
4452 * This is used to free the function mapper. The @free_func is optional
4453 * and can be used if the data needs to be freed as well.
4455 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4456 ftrace_mapper_func free_func)
4458 struct ftrace_func_entry *entry;
4459 struct ftrace_func_map *map;
4460 struct hlist_head *hhd;
4466 if (free_func && mapper->hash.count) {
4467 size = 1 << mapper->hash.size_bits;
4468 for (i = 0; i < size; i++) {
4469 hhd = &mapper->hash.buckets[i];
4470 hlist_for_each_entry(entry, hhd, hlist) {
4471 map = (struct ftrace_func_map *)entry;
4476 free_ftrace_hash(&mapper->hash);
4479 static void release_probe(struct ftrace_func_probe *probe)
4481 struct ftrace_probe_ops *probe_ops;
4483 mutex_lock(&ftrace_lock);
4485 WARN_ON(probe->ref <= 0);
4487 /* Subtract the ref that was used to protect this instance */
4491 probe_ops = probe->probe_ops;
4493 * Sending zero as ip tells probe_ops to free
4494 * the probe->data itself
4496 if (probe_ops->free)
4497 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4498 list_del(&probe->list);
4501 mutex_unlock(&ftrace_lock);
4504 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4507 * Add one ref to keep it from being freed when releasing the
4508 * ftrace_lock mutex.
4514 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4515 struct ftrace_probe_ops *probe_ops,
4518 struct ftrace_func_entry *entry;
4519 struct ftrace_func_probe *probe;
4520 struct ftrace_hash **orig_hash;
4521 struct ftrace_hash *old_hash;
4522 struct ftrace_hash *hash;
4531 /* We do not support '!' for function probes */
4532 if (WARN_ON(glob[0] == '!'))
4536 mutex_lock(&ftrace_lock);
4537 /* Check if the probe_ops is already registered */
4538 list_for_each_entry(probe, &tr->func_probes, list) {
4539 if (probe->probe_ops == probe_ops)
4542 if (&probe->list == &tr->func_probes) {
4543 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4545 mutex_unlock(&ftrace_lock);
4548 probe->probe_ops = probe_ops;
4549 probe->ops.func = function_trace_probe_call;
4551 ftrace_ops_init(&probe->ops);
4552 list_add(&probe->list, &tr->func_probes);
4555 acquire_probe_locked(probe);
4557 mutex_unlock(&ftrace_lock);
4560 * Note, there's a small window here that the func_hash->filter_hash
4561 * may be NULL or empty. Need to be careful when reading the loop.
4563 mutex_lock(&probe->ops.func_hash->regex_lock);
4565 orig_hash = &probe->ops.func_hash->filter_hash;
4566 old_hash = *orig_hash;
4567 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4574 ret = ftrace_match_records(hash, glob, strlen(glob));
4576 /* Nothing found? */
4583 size = 1 << hash->size_bits;
4584 for (i = 0; i < size; i++) {
4585 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4586 if (ftrace_lookup_ip(old_hash, entry->ip))
4589 * The caller might want to do something special
4590 * for each function we find. We call the callback
4591 * to give the caller an opportunity to do so.
4593 if (probe_ops->init) {
4594 ret = probe_ops->init(probe_ops, tr,
4598 if (probe_ops->free && count)
4599 probe_ops->free(probe_ops, tr,
4609 mutex_lock(&ftrace_lock);
4612 /* Nothing was added? */
4617 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4622 /* One ref for each new function traced */
4623 probe->ref += count;
4625 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4626 ret = ftrace_startup(&probe->ops, 0);
4629 mutex_unlock(&ftrace_lock);
4634 mutex_unlock(&probe->ops.func_hash->regex_lock);
4635 free_ftrace_hash(hash);
4637 release_probe(probe);
4642 if (!probe_ops->free || !count)
4645 /* Failed to do the move, need to call the free functions */
4646 for (i = 0; i < size; i++) {
4647 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4648 if (ftrace_lookup_ip(old_hash, entry->ip))
4650 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4657 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4658 struct ftrace_probe_ops *probe_ops)
4660 struct ftrace_ops_hash old_hash_ops;
4661 struct ftrace_func_entry *entry;
4662 struct ftrace_func_probe *probe;
4663 struct ftrace_glob func_g;
4664 struct ftrace_hash **orig_hash;
4665 struct ftrace_hash *old_hash;
4666 struct ftrace_hash *hash = NULL;
4667 struct hlist_node *tmp;
4668 struct hlist_head hhd;
4669 char str[KSYM_SYMBOL_LEN];
4671 int i, ret = -ENODEV;
4674 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4675 func_g.search = NULL;
4679 func_g.type = filter_parse_regex(glob, strlen(glob),
4680 &func_g.search, ¬);
4681 func_g.len = strlen(func_g.search);
4683 /* we do not support '!' for function probes */
4688 mutex_lock(&ftrace_lock);
4689 /* Check if the probe_ops is already registered */
4690 list_for_each_entry(probe, &tr->func_probes, list) {
4691 if (probe->probe_ops == probe_ops)
4694 if (&probe->list == &tr->func_probes)
4695 goto err_unlock_ftrace;
4698 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4699 goto err_unlock_ftrace;
4701 acquire_probe_locked(probe);
4703 mutex_unlock(&ftrace_lock);
4705 mutex_lock(&probe->ops.func_hash->regex_lock);
4707 orig_hash = &probe->ops.func_hash->filter_hash;
4708 old_hash = *orig_hash;
4710 if (ftrace_hash_empty(old_hash))
4713 old_hash_ops.filter_hash = old_hash;
4714 /* Probes only have filters */
4715 old_hash_ops.notrace_hash = NULL;
4718 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4722 INIT_HLIST_HEAD(&hhd);
4724 size = 1 << hash->size_bits;
4725 for (i = 0; i < size; i++) {
4726 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4728 if (func_g.search) {
4729 kallsyms_lookup(entry->ip, NULL, NULL,
4731 if (!ftrace_match(str, &func_g))
4735 remove_hash_entry(hash, entry);
4736 hlist_add_head(&entry->hlist, &hhd);
4740 /* Nothing found? */
4746 mutex_lock(&ftrace_lock);
4748 WARN_ON(probe->ref < count);
4750 probe->ref -= count;
4752 if (ftrace_hash_empty(hash))
4753 ftrace_shutdown(&probe->ops, 0);
4755 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4758 /* still need to update the function call sites */
4759 if (ftrace_enabled && !ftrace_hash_empty(hash))
4760 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4764 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4765 hlist_del(&entry->hlist);
4766 if (probe_ops->free)
4767 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4770 mutex_unlock(&ftrace_lock);
4773 mutex_unlock(&probe->ops.func_hash->regex_lock);
4774 free_ftrace_hash(hash);
4776 release_probe(probe);
4781 mutex_unlock(&ftrace_lock);
4785 void clear_ftrace_function_probes(struct trace_array *tr)
4787 struct ftrace_func_probe *probe, *n;
4789 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4790 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4793 static LIST_HEAD(ftrace_commands);
4794 static DEFINE_MUTEX(ftrace_cmd_mutex);
4797 * Currently we only register ftrace commands from __init, so mark this
4800 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4802 struct ftrace_func_command *p;
4805 mutex_lock(&ftrace_cmd_mutex);
4806 list_for_each_entry(p, &ftrace_commands, list) {
4807 if (strcmp(cmd->name, p->name) == 0) {
4812 list_add(&cmd->list, &ftrace_commands);
4814 mutex_unlock(&ftrace_cmd_mutex);
4820 * Currently we only unregister ftrace commands from __init, so mark
4823 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4825 struct ftrace_func_command *p, *n;
4828 mutex_lock(&ftrace_cmd_mutex);
4829 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4830 if (strcmp(cmd->name, p->name) == 0) {
4832 list_del_init(&p->list);
4837 mutex_unlock(&ftrace_cmd_mutex);
4842 static int ftrace_process_regex(struct ftrace_iterator *iter,
4843 char *buff, int len, int enable)
4845 struct ftrace_hash *hash = iter->hash;
4846 struct trace_array *tr = iter->ops->private;
4847 char *func, *command, *next = buff;
4848 struct ftrace_func_command *p;
4851 func = strsep(&next, ":");
4854 ret = ftrace_match_records(hash, func, len);
4864 command = strsep(&next, ":");
4866 mutex_lock(&ftrace_cmd_mutex);
4867 list_for_each_entry(p, &ftrace_commands, list) {
4868 if (strcmp(p->name, command) == 0) {
4869 ret = p->func(tr, hash, func, command, next, enable);
4874 mutex_unlock(&ftrace_cmd_mutex);
4880 ftrace_regex_write(struct file *file, const char __user *ubuf,
4881 size_t cnt, loff_t *ppos, int enable)
4883 struct ftrace_iterator *iter;
4884 struct trace_parser *parser;
4890 if (file->f_mode & FMODE_READ) {
4891 struct seq_file *m = file->private_data;
4894 iter = file->private_data;
4896 if (unlikely(ftrace_disabled))
4899 /* iter->hash is a local copy, so we don't need regex_lock */
4901 parser = &iter->parser;
4902 read = trace_get_user(parser, ubuf, cnt, ppos);
4904 if (read >= 0 && trace_parser_loaded(parser) &&
4905 !trace_parser_cont(parser)) {
4906 ret = ftrace_process_regex(iter, parser->buffer,
4907 parser->idx, enable);
4908 trace_parser_clear(parser);
4919 ftrace_filter_write(struct file *file, const char __user *ubuf,
4920 size_t cnt, loff_t *ppos)
4922 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4926 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4927 size_t cnt, loff_t *ppos)
4929 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4933 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4935 struct ftrace_func_entry *entry;
4937 if (!ftrace_location(ip))
4941 entry = ftrace_lookup_ip(hash, ip);
4944 free_hash_entry(hash, entry);
4948 return add_hash_entry(hash, ip);
4952 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4953 unsigned long ip, int remove, int reset, int enable)
4955 struct ftrace_hash **orig_hash;
4956 struct ftrace_hash *hash;
4959 if (unlikely(ftrace_disabled))
4962 mutex_lock(&ops->func_hash->regex_lock);
4965 orig_hash = &ops->func_hash->filter_hash;
4967 orig_hash = &ops->func_hash->notrace_hash;
4970 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4972 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4976 goto out_regex_unlock;
4979 if (buf && !ftrace_match_records(hash, buf, len)) {
4981 goto out_regex_unlock;
4984 ret = ftrace_match_addr(hash, ip, remove);
4986 goto out_regex_unlock;
4989 mutex_lock(&ftrace_lock);
4990 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4991 mutex_unlock(&ftrace_lock);
4994 mutex_unlock(&ops->func_hash->regex_lock);
4996 free_ftrace_hash(hash);
5001 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
5002 int reset, int enable)
5004 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
5007 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5009 struct ftrace_direct_func {
5010 struct list_head next;
5015 static LIST_HEAD(ftrace_direct_funcs);
5018 * ftrace_find_direct_func - test an address if it is a registered direct caller
5019 * @addr: The address of a registered direct caller
5021 * This searches to see if a ftrace direct caller has been registered
5022 * at a specific address, and if so, it returns a descriptor for it.
5024 * This can be used by architecture code to see if an address is
5025 * a direct caller (trampoline) attached to a fentry/mcount location.
5026 * This is useful for the function_graph tracer, as it may need to
5027 * do adjustments if it traced a location that also has a direct
5028 * trampoline attached to it.
5030 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5032 struct ftrace_direct_func *entry;
5035 /* May be called by fgraph trampoline (protected by rcu tasks) */
5036 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5037 if (entry->addr == addr) {
5049 * register_ftrace_direct - Call a custom trampoline directly
5050 * @ip: The address of the nop at the beginning of a function
5051 * @addr: The address of the trampoline to call at @ip
5053 * This is used to connect a direct call from the nop location (@ip)
5054 * at the start of ftrace traced functions. The location that it calls
5055 * (@addr) must be able to handle a direct call, and save the parameters
5056 * of the function being traced, and restore them (or inject new ones
5057 * if needed), before returning.
5061 * -EBUSY - Another direct function is already attached (there can be only one)
5062 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5063 * -ENOMEM - There was an allocation failure.
5065 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5067 struct ftrace_direct_func *direct;
5068 struct ftrace_func_entry *entry;
5069 struct ftrace_hash *free_hash = NULL;
5070 struct dyn_ftrace *rec;
5073 mutex_lock(&direct_mutex);
5075 /* See if there's a direct function at @ip already */
5076 if (ftrace_find_rec_direct(ip))
5080 rec = lookup_rec(ip, ip);
5085 * Check if the rec says it has a direct call but we didn't
5088 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5091 /* Make sure the ip points to the exact record */
5092 if (ip != rec->ip) {
5094 /* Need to check this ip for a direct. */
5095 if (ftrace_find_rec_direct(ip))
5100 if (ftrace_hash_empty(direct_functions) ||
5101 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5102 struct ftrace_hash *new_hash;
5103 int size = ftrace_hash_empty(direct_functions) ? 0 :
5104 direct_functions->count + 1;
5109 new_hash = dup_hash(direct_functions, size);
5113 free_hash = direct_functions;
5114 direct_functions = new_hash;
5117 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5121 direct = ftrace_find_direct_func(addr);
5123 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5128 direct->addr = addr;
5130 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5131 ftrace_direct_func_count++;
5135 entry->direct = addr;
5136 __add_hash_entry(direct_functions, entry);
5138 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5140 remove_hash_entry(direct_functions, entry);
5142 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5143 ret = register_ftrace_function(&direct_ops);
5145 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5150 if (!direct->count) {
5151 list_del_rcu(&direct->next);
5152 synchronize_rcu_tasks();
5155 free_ftrace_hash(free_hash);
5157 ftrace_direct_func_count--;
5163 mutex_unlock(&direct_mutex);
5166 synchronize_rcu_tasks();
5167 free_ftrace_hash(free_hash);
5172 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5174 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5175 struct dyn_ftrace **recp)
5177 struct ftrace_func_entry *entry;
5178 struct dyn_ftrace *rec;
5180 rec = lookup_rec(*ip, *ip);
5184 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5186 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5190 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5192 /* Passed in ip just needs to be on the call site */
5201 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5203 struct ftrace_direct_func *direct;
5204 struct ftrace_func_entry *entry;
5207 mutex_lock(&direct_mutex);
5209 entry = find_direct_entry(&ip, NULL);
5213 if (direct_functions->count == 1)
5214 unregister_ftrace_function(&direct_ops);
5216 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5220 remove_hash_entry(direct_functions, entry);
5222 direct = ftrace_find_direct_func(addr);
5223 if (!WARN_ON(!direct)) {
5224 /* This is the good path (see the ! before WARN) */
5226 WARN_ON(direct->count < 0);
5227 if (!direct->count) {
5228 list_del_rcu(&direct->next);
5229 synchronize_rcu_tasks();
5232 ftrace_direct_func_count--;
5236 mutex_unlock(&direct_mutex);
5240 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5242 static struct ftrace_ops stub_ops = {
5243 .func = ftrace_stub,
5247 * ftrace_modify_direct_caller - modify ftrace nop directly
5248 * @entry: The ftrace hash entry of the direct helper for @rec
5249 * @rec: The record representing the function site to patch
5250 * @old_addr: The location that the site at @rec->ip currently calls
5251 * @new_addr: The location that the site at @rec->ip should call
5253 * An architecture may overwrite this function to optimize the
5254 * changing of the direct callback on an ftrace nop location.
5255 * This is called with the ftrace_lock mutex held, and no other
5256 * ftrace callbacks are on the associated record (@rec). Thus,
5257 * it is safe to modify the ftrace record, where it should be
5258 * currently calling @old_addr directly, to call @new_addr.
5260 * Safety checks should be made to make sure that the code at
5261 * @rec->ip is currently calling @old_addr. And this must
5262 * also update entry->direct to @new_addr.
5264 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5265 struct dyn_ftrace *rec,
5266 unsigned long old_addr,
5267 unsigned long new_addr)
5269 unsigned long ip = rec->ip;
5273 * The ftrace_lock was used to determine if the record
5274 * had more than one registered user to it. If it did,
5275 * we needed to prevent that from changing to do the quick
5276 * switch. But if it did not (only a direct caller was attached)
5277 * then this function is called. But this function can deal
5278 * with attached callers to the rec that we care about, and
5279 * since this function uses standard ftrace calls that take
5280 * the ftrace_lock mutex, we need to release it.
5282 mutex_unlock(&ftrace_lock);
5285 * By setting a stub function at the same address, we force
5286 * the code to call the iterator and the direct_ops helper.
5287 * This means that @ip does not call the direct call, and
5288 * we can simply modify it.
5290 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5294 ret = register_ftrace_function(&stub_ops);
5296 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5300 entry->direct = new_addr;
5303 * By removing the stub, we put back the direct call, calling
5306 unregister_ftrace_function(&stub_ops);
5307 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5310 mutex_lock(&ftrace_lock);
5316 * modify_ftrace_direct - Modify an existing direct call to call something else
5317 * @ip: The instruction pointer to modify
5318 * @old_addr: The address that the current @ip calls directly
5319 * @new_addr: The address that the @ip should call
5321 * This modifies a ftrace direct caller at an instruction pointer without
5322 * having to disable it first. The direct call will switch over to the
5323 * @new_addr without missing anything.
5325 * Returns: zero on success. Non zero on error, which includes:
5326 * -ENODEV : the @ip given has no direct caller attached
5327 * -EINVAL : the @old_addr does not match the current direct caller
5329 int modify_ftrace_direct(unsigned long ip,
5330 unsigned long old_addr, unsigned long new_addr)
5332 struct ftrace_func_entry *entry;
5333 struct dyn_ftrace *rec;
5336 mutex_lock(&direct_mutex);
5338 mutex_lock(&ftrace_lock);
5339 entry = find_direct_entry(&ip, &rec);
5344 if (entry->direct != old_addr)
5348 * If there's no other ftrace callback on the rec->ip location,
5349 * then it can be changed directly by the architecture.
5350 * If there is another caller, then we just need to change the
5351 * direct caller helper to point to @new_addr.
5353 if (ftrace_rec_count(rec) == 1) {
5354 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5356 entry->direct = new_addr;
5361 mutex_unlock(&ftrace_lock);
5362 mutex_unlock(&direct_mutex);
5365 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5366 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5369 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5370 * @ops - the ops to set the filter with
5371 * @ip - the address to add to or remove from the filter.
5372 * @remove - non zero to remove the ip from the filter
5373 * @reset - non zero to reset all filters before applying this filter.
5375 * Filters denote which functions should be enabled when tracing is enabled
5376 * If @ip is NULL, it failes to update filter.
5378 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5379 int remove, int reset)
5381 ftrace_ops_init(ops);
5382 return ftrace_set_addr(ops, ip, remove, reset, 1);
5384 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5387 * ftrace_ops_set_global_filter - setup ops to use global filters
5388 * @ops - the ops which will use the global filters
5390 * ftrace users who need global function trace filtering should call this.
5391 * It can set the global filter only if ops were not initialized before.
5393 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5395 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5398 ftrace_ops_init(ops);
5399 ops->func_hash = &global_ops.local_hash;
5401 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5404 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5405 int reset, int enable)
5407 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5411 * ftrace_set_filter - set a function to filter on in ftrace
5412 * @ops - the ops to set the filter with
5413 * @buf - the string that holds the function filter text.
5414 * @len - the length of the string.
5415 * @reset - non zero to reset all filters before applying this filter.
5417 * Filters denote which functions should be enabled when tracing is enabled.
5418 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5420 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5423 ftrace_ops_init(ops);
5424 return ftrace_set_regex(ops, buf, len, reset, 1);
5426 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5429 * ftrace_set_notrace - set a function to not trace in ftrace
5430 * @ops - the ops to set the notrace filter with
5431 * @buf - the string that holds the function notrace text.
5432 * @len - the length of the string.
5433 * @reset - non zero to reset all filters before applying this filter.
5435 * Notrace Filters denote which functions should not be enabled when tracing
5436 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5439 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5442 ftrace_ops_init(ops);
5443 return ftrace_set_regex(ops, buf, len, reset, 0);
5445 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5447 * ftrace_set_global_filter - set a function to filter on with global tracers
5448 * @buf - the string that holds the function filter text.
5449 * @len - the length of the string.
5450 * @reset - non zero to reset all filters before applying this filter.
5452 * Filters denote which functions should be enabled when tracing is enabled.
5453 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5455 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5457 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5459 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5462 * ftrace_set_global_notrace - set a function to not trace with global tracers
5463 * @buf - the string that holds the function notrace text.
5464 * @len - the length of the string.
5465 * @reset - non zero to reset all filters before applying this filter.
5467 * Notrace Filters denote which functions should not be enabled when tracing
5468 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5471 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5473 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5475 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5478 * command line interface to allow users to set filters on boot up.
5480 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5481 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5482 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5484 /* Used by function selftest to not test if filter is set */
5485 bool ftrace_filter_param __initdata;
5487 static int __init set_ftrace_notrace(char *str)
5489 ftrace_filter_param = true;
5490 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5493 __setup("ftrace_notrace=", set_ftrace_notrace);
5495 static int __init set_ftrace_filter(char *str)
5497 ftrace_filter_param = true;
5498 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5501 __setup("ftrace_filter=", set_ftrace_filter);
5503 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5504 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5505 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5506 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5508 static int __init set_graph_function(char *str)
5510 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5513 __setup("ftrace_graph_filter=", set_graph_function);
5515 static int __init set_graph_notrace_function(char *str)
5517 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5520 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5522 static int __init set_graph_max_depth_function(char *str)
5526 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5529 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5531 static void __init set_ftrace_early_graph(char *buf, int enable)
5535 struct ftrace_hash *hash;
5537 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5538 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5542 func = strsep(&buf, ",");
5543 /* we allow only one expression at a time */
5544 ret = ftrace_graph_set_hash(hash, func);
5546 printk(KERN_DEBUG "ftrace: function %s not "
5547 "traceable\n", func);
5551 ftrace_graph_hash = hash;
5553 ftrace_graph_notrace_hash = hash;
5555 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5558 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5562 ftrace_ops_init(ops);
5565 func = strsep(&buf, ",");
5566 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5570 static void __init set_ftrace_early_filters(void)
5572 if (ftrace_filter_buf[0])
5573 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5574 if (ftrace_notrace_buf[0])
5575 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5576 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5577 if (ftrace_graph_buf[0])
5578 set_ftrace_early_graph(ftrace_graph_buf, 1);
5579 if (ftrace_graph_notrace_buf[0])
5580 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5581 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5584 int ftrace_regex_release(struct inode *inode, struct file *file)
5586 struct seq_file *m = (struct seq_file *)file->private_data;
5587 struct ftrace_iterator *iter;
5588 struct ftrace_hash **orig_hash;
5589 struct trace_parser *parser;
5593 if (file->f_mode & FMODE_READ) {
5595 seq_release(inode, file);
5597 iter = file->private_data;
5599 parser = &iter->parser;
5600 if (trace_parser_loaded(parser)) {
5601 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5604 trace_parser_put(parser);
5606 mutex_lock(&iter->ops->func_hash->regex_lock);
5608 if (file->f_mode & FMODE_WRITE) {
5609 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5612 orig_hash = &iter->ops->func_hash->filter_hash;
5613 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5614 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5616 orig_hash = &iter->ops->func_hash->notrace_hash;
5618 mutex_lock(&ftrace_lock);
5619 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5620 iter->hash, filter_hash);
5621 mutex_unlock(&ftrace_lock);
5623 /* For read only, the hash is the ops hash */
5627 mutex_unlock(&iter->ops->func_hash->regex_lock);
5628 free_ftrace_hash(iter->hash);
5630 trace_array_put(iter->tr);
5636 static const struct file_operations ftrace_avail_fops = {
5637 .open = ftrace_avail_open,
5639 .llseek = seq_lseek,
5640 .release = seq_release_private,
5643 static const struct file_operations ftrace_enabled_fops = {
5644 .open = ftrace_enabled_open,
5646 .llseek = seq_lseek,
5647 .release = seq_release_private,
5650 static const struct file_operations ftrace_filter_fops = {
5651 .open = ftrace_filter_open,
5653 .write = ftrace_filter_write,
5654 .llseek = tracing_lseek,
5655 .release = ftrace_regex_release,
5658 static const struct file_operations ftrace_notrace_fops = {
5659 .open = ftrace_notrace_open,
5661 .write = ftrace_notrace_write,
5662 .llseek = tracing_lseek,
5663 .release = ftrace_regex_release,
5666 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5668 static DEFINE_MUTEX(graph_lock);
5670 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5671 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5673 enum graph_filter_type {
5674 GRAPH_FILTER_NOTRACE = 0,
5675 GRAPH_FILTER_FUNCTION,
5678 #define FTRACE_GRAPH_EMPTY ((void *)1)
5680 struct ftrace_graph_data {
5681 struct ftrace_hash *hash;
5682 struct ftrace_func_entry *entry;
5683 int idx; /* for hash table iteration */
5684 enum graph_filter_type type;
5685 struct ftrace_hash *new_hash;
5686 const struct seq_operations *seq_ops;
5687 struct trace_parser parser;
5691 __g_next(struct seq_file *m, loff_t *pos)
5693 struct ftrace_graph_data *fgd = m->private;
5694 struct ftrace_func_entry *entry = fgd->entry;
5695 struct hlist_head *head;
5696 int i, idx = fgd->idx;
5698 if (*pos >= fgd->hash->count)
5702 hlist_for_each_entry_continue(entry, hlist) {
5710 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5711 head = &fgd->hash->buckets[i];
5712 hlist_for_each_entry(entry, head, hlist) {
5722 g_next(struct seq_file *m, void *v, loff_t *pos)
5725 return __g_next(m, pos);
5728 static void *g_start(struct seq_file *m, loff_t *pos)
5730 struct ftrace_graph_data *fgd = m->private;
5732 mutex_lock(&graph_lock);
5734 if (fgd->type == GRAPH_FILTER_FUNCTION)
5735 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5736 lockdep_is_held(&graph_lock));
5738 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5739 lockdep_is_held(&graph_lock));
5741 /* Nothing, tell g_show to print all functions are enabled */
5742 if (ftrace_hash_empty(fgd->hash) && !*pos)
5743 return FTRACE_GRAPH_EMPTY;
5747 return __g_next(m, pos);
5750 static void g_stop(struct seq_file *m, void *p)
5752 mutex_unlock(&graph_lock);
5755 static int g_show(struct seq_file *m, void *v)
5757 struct ftrace_func_entry *entry = v;
5762 if (entry == FTRACE_GRAPH_EMPTY) {
5763 struct ftrace_graph_data *fgd = m->private;
5765 if (fgd->type == GRAPH_FILTER_FUNCTION)
5766 seq_puts(m, "#### all functions enabled ####\n");
5768 seq_puts(m, "#### no functions disabled ####\n");
5772 seq_printf(m, "%ps\n", (void *)entry->ip);
5777 static const struct seq_operations ftrace_graph_seq_ops = {
5785 __ftrace_graph_open(struct inode *inode, struct file *file,
5786 struct ftrace_graph_data *fgd)
5789 struct ftrace_hash *new_hash = NULL;
5791 ret = security_locked_down(LOCKDOWN_TRACEFS);
5795 if (file->f_mode & FMODE_WRITE) {
5796 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5798 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5801 if (file->f_flags & O_TRUNC)
5802 new_hash = alloc_ftrace_hash(size_bits);
5804 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5812 if (file->f_mode & FMODE_READ) {
5813 ret = seq_open(file, &ftrace_graph_seq_ops);
5815 struct seq_file *m = file->private_data;
5819 free_ftrace_hash(new_hash);
5823 file->private_data = fgd;
5826 if (ret < 0 && file->f_mode & FMODE_WRITE)
5827 trace_parser_put(&fgd->parser);
5829 fgd->new_hash = new_hash;
5832 * All uses of fgd->hash must be taken with the graph_lock
5833 * held. The graph_lock is going to be released, so force
5834 * fgd->hash to be reinitialized when it is taken again.
5842 ftrace_graph_open(struct inode *inode, struct file *file)
5844 struct ftrace_graph_data *fgd;
5847 if (unlikely(ftrace_disabled))
5850 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5854 mutex_lock(&graph_lock);
5856 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5857 lockdep_is_held(&graph_lock));
5858 fgd->type = GRAPH_FILTER_FUNCTION;
5859 fgd->seq_ops = &ftrace_graph_seq_ops;
5861 ret = __ftrace_graph_open(inode, file, fgd);
5865 mutex_unlock(&graph_lock);
5870 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5872 struct ftrace_graph_data *fgd;
5875 if (unlikely(ftrace_disabled))
5878 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5882 mutex_lock(&graph_lock);
5884 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5885 lockdep_is_held(&graph_lock));
5886 fgd->type = GRAPH_FILTER_NOTRACE;
5887 fgd->seq_ops = &ftrace_graph_seq_ops;
5889 ret = __ftrace_graph_open(inode, file, fgd);
5893 mutex_unlock(&graph_lock);
5898 ftrace_graph_release(struct inode *inode, struct file *file)
5900 struct ftrace_graph_data *fgd;
5901 struct ftrace_hash *old_hash, *new_hash;
5902 struct trace_parser *parser;
5905 if (file->f_mode & FMODE_READ) {
5906 struct seq_file *m = file->private_data;
5909 seq_release(inode, file);
5911 fgd = file->private_data;
5915 if (file->f_mode & FMODE_WRITE) {
5917 parser = &fgd->parser;
5919 if (trace_parser_loaded((parser))) {
5920 ret = ftrace_graph_set_hash(fgd->new_hash,
5924 trace_parser_put(parser);
5926 new_hash = __ftrace_hash_move(fgd->new_hash);
5932 mutex_lock(&graph_lock);
5934 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5935 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5936 lockdep_is_held(&graph_lock));
5937 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5939 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5940 lockdep_is_held(&graph_lock));
5941 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5944 mutex_unlock(&graph_lock);
5947 * We need to do a hard force of sched synchronization.
5948 * This is because we use preempt_disable() to do RCU, but
5949 * the function tracers can be called where RCU is not watching
5950 * (like before user_exit()). We can not rely on the RCU
5951 * infrastructure to do the synchronization, thus we must do it
5954 synchronize_rcu_tasks_rude();
5956 free_ftrace_hash(old_hash);
5960 free_ftrace_hash(fgd->new_hash);
5967 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5969 struct ftrace_glob func_g;
5970 struct dyn_ftrace *rec;
5971 struct ftrace_page *pg;
5972 struct ftrace_func_entry *entry;
5977 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5978 &func_g.search, ¬);
5980 func_g.len = strlen(func_g.search);
5982 mutex_lock(&ftrace_lock);
5984 if (unlikely(ftrace_disabled)) {
5985 mutex_unlock(&ftrace_lock);
5989 do_for_each_ftrace_rec(pg, rec) {
5991 if (rec->flags & FTRACE_FL_DISABLED)
5994 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5995 entry = ftrace_lookup_ip(hash, rec->ip);
6002 if (add_hash_entry(hash, rec->ip) < 0)
6006 free_hash_entry(hash, entry);
6011 } while_for_each_ftrace_rec();
6013 mutex_unlock(&ftrace_lock);
6022 ftrace_graph_write(struct file *file, const char __user *ubuf,
6023 size_t cnt, loff_t *ppos)
6025 ssize_t read, ret = 0;
6026 struct ftrace_graph_data *fgd = file->private_data;
6027 struct trace_parser *parser;
6032 /* Read mode uses seq functions */
6033 if (file->f_mode & FMODE_READ) {
6034 struct seq_file *m = file->private_data;
6038 parser = &fgd->parser;
6040 read = trace_get_user(parser, ubuf, cnt, ppos);
6042 if (read >= 0 && trace_parser_loaded(parser) &&
6043 !trace_parser_cont(parser)) {
6045 ret = ftrace_graph_set_hash(fgd->new_hash,
6047 trace_parser_clear(parser);
6056 static const struct file_operations ftrace_graph_fops = {
6057 .open = ftrace_graph_open,
6059 .write = ftrace_graph_write,
6060 .llseek = tracing_lseek,
6061 .release = ftrace_graph_release,
6064 static const struct file_operations ftrace_graph_notrace_fops = {
6065 .open = ftrace_graph_notrace_open,
6067 .write = ftrace_graph_write,
6068 .llseek = tracing_lseek,
6069 .release = ftrace_graph_release,
6071 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6073 void ftrace_create_filter_files(struct ftrace_ops *ops,
6074 struct dentry *parent)
6077 trace_create_file("set_ftrace_filter", 0644, parent,
6078 ops, &ftrace_filter_fops);
6080 trace_create_file("set_ftrace_notrace", 0644, parent,
6081 ops, &ftrace_notrace_fops);
6085 * The name "destroy_filter_files" is really a misnomer. Although
6086 * in the future, it may actually delete the files, but this is
6087 * really intended to make sure the ops passed in are disabled
6088 * and that when this function returns, the caller is free to
6091 * The "destroy" name is only to match the "create" name that this
6092 * should be paired with.
6094 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6096 mutex_lock(&ftrace_lock);
6097 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6098 ftrace_shutdown(ops, 0);
6099 ops->flags |= FTRACE_OPS_FL_DELETED;
6100 ftrace_free_filter(ops);
6101 mutex_unlock(&ftrace_lock);
6104 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6107 trace_create_file("available_filter_functions", 0444,
6108 d_tracer, NULL, &ftrace_avail_fops);
6110 trace_create_file("enabled_functions", 0444,
6111 d_tracer, NULL, &ftrace_enabled_fops);
6113 ftrace_create_filter_files(&global_ops, d_tracer);
6115 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6116 trace_create_file("set_graph_function", 0644, d_tracer,
6118 &ftrace_graph_fops);
6119 trace_create_file("set_graph_notrace", 0644, d_tracer,
6121 &ftrace_graph_notrace_fops);
6122 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6127 static int ftrace_cmp_ips(const void *a, const void *b)
6129 const unsigned long *ipa = a;
6130 const unsigned long *ipb = b;
6139 static int ftrace_process_locs(struct module *mod,
6140 unsigned long *start,
6143 struct ftrace_page *start_pg;
6144 struct ftrace_page *pg;
6145 struct dyn_ftrace *rec;
6146 unsigned long count;
6149 unsigned long flags = 0; /* Shut up gcc */
6152 count = end - start;
6157 sort(start, count, sizeof(*start),
6158 ftrace_cmp_ips, NULL);
6160 start_pg = ftrace_allocate_pages(count);
6164 mutex_lock(&ftrace_lock);
6167 * Core and each module needs their own pages, as
6168 * modules will free them when they are removed.
6169 * Force a new page to be allocated for modules.
6172 WARN_ON(ftrace_pages || ftrace_pages_start);
6173 /* First initialization */
6174 ftrace_pages = ftrace_pages_start = start_pg;
6179 if (WARN_ON(ftrace_pages->next)) {
6180 /* Hmm, we have free pages? */
6181 while (ftrace_pages->next)
6182 ftrace_pages = ftrace_pages->next;
6185 ftrace_pages->next = start_pg;
6191 addr = ftrace_call_adjust(*p++);
6193 * Some architecture linkers will pad between
6194 * the different mcount_loc sections of different
6195 * object files to satisfy alignments.
6196 * Skip any NULL pointers.
6201 if (pg->index == pg->size) {
6202 /* We should have allocated enough */
6203 if (WARN_ON(!pg->next))
6208 rec = &pg->records[pg->index++];
6212 /* We should have used all pages */
6215 /* Assign the last page to ftrace_pages */
6219 * We only need to disable interrupts on start up
6220 * because we are modifying code that an interrupt
6221 * may execute, and the modification is not atomic.
6222 * But for modules, nothing runs the code we modify
6223 * until we are finished with it, and there's no
6224 * reason to cause large interrupt latencies while we do it.
6227 local_irq_save(flags);
6228 ftrace_update_code(mod, start_pg);
6230 local_irq_restore(flags);
6233 mutex_unlock(&ftrace_lock);
6238 struct ftrace_mod_func {
6239 struct list_head list;
6245 struct ftrace_mod_map {
6246 struct rcu_head rcu;
6247 struct list_head list;
6249 unsigned long start_addr;
6250 unsigned long end_addr;
6251 struct list_head funcs;
6252 unsigned int num_funcs;
6255 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6256 unsigned long *value, char *type,
6257 char *name, char *module_name,
6260 struct ftrace_ops *op;
6262 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6263 if (!op->trampoline || symnum--)
6265 *value = op->trampoline;
6267 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6268 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6276 #ifdef CONFIG_MODULES
6278 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6280 static LIST_HEAD(ftrace_mod_maps);
6282 static int referenced_filters(struct dyn_ftrace *rec)
6284 struct ftrace_ops *ops;
6287 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6288 if (ops_references_rec(ops, rec)) {
6289 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6291 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6294 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6295 rec->flags |= FTRACE_FL_REGS;
6296 if (cnt == 1 && ops->trampoline)
6297 rec->flags |= FTRACE_FL_TRAMP;
6299 rec->flags &= ~FTRACE_FL_TRAMP;
6307 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6309 struct ftrace_func_entry *entry;
6310 struct dyn_ftrace *rec;
6313 if (ftrace_hash_empty(hash))
6316 for (i = 0; i < pg->index; i++) {
6317 rec = &pg->records[i];
6318 entry = __ftrace_lookup_ip(hash, rec->ip);
6320 * Do not allow this rec to match again.
6321 * Yeah, it may waste some memory, but will be removed
6322 * if/when the hash is modified again.
6329 /* Clear any records from hashs */
6330 static void clear_mod_from_hashes(struct ftrace_page *pg)
6332 struct trace_array *tr;
6334 mutex_lock(&trace_types_lock);
6335 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6336 if (!tr->ops || !tr->ops->func_hash)
6338 mutex_lock(&tr->ops->func_hash->regex_lock);
6339 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6340 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6341 mutex_unlock(&tr->ops->func_hash->regex_lock);
6343 mutex_unlock(&trace_types_lock);
6346 static void ftrace_free_mod_map(struct rcu_head *rcu)
6348 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6349 struct ftrace_mod_func *mod_func;
6350 struct ftrace_mod_func *n;
6352 /* All the contents of mod_map are now not visible to readers */
6353 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6354 kfree(mod_func->name);
6355 list_del(&mod_func->list);
6362 void ftrace_release_mod(struct module *mod)
6364 struct ftrace_mod_map *mod_map;
6365 struct ftrace_mod_map *n;
6366 struct dyn_ftrace *rec;
6367 struct ftrace_page **last_pg;
6368 struct ftrace_page *tmp_page = NULL;
6369 struct ftrace_page *pg;
6372 mutex_lock(&ftrace_lock);
6374 if (ftrace_disabled)
6377 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6378 if (mod_map->mod == mod) {
6379 list_del_rcu(&mod_map->list);
6380 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6386 * Each module has its own ftrace_pages, remove
6387 * them from the list.
6389 last_pg = &ftrace_pages_start;
6390 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6391 rec = &pg->records[0];
6392 if (within_module_core(rec->ip, mod) ||
6393 within_module_init(rec->ip, mod)) {
6395 * As core pages are first, the first
6396 * page should never be a module page.
6398 if (WARN_ON(pg == ftrace_pages_start))
6401 /* Check if we are deleting the last page */
6402 if (pg == ftrace_pages)
6403 ftrace_pages = next_to_ftrace_page(last_pg);
6405 ftrace_update_tot_cnt -= pg->index;
6406 *last_pg = pg->next;
6408 pg->next = tmp_page;
6411 last_pg = &pg->next;
6414 mutex_unlock(&ftrace_lock);
6416 for (pg = tmp_page; pg; pg = tmp_page) {
6418 /* Needs to be called outside of ftrace_lock */
6419 clear_mod_from_hashes(pg);
6421 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6422 free_pages((unsigned long)pg->records, order);
6423 tmp_page = pg->next;
6425 ftrace_number_of_pages -= 1 << order;
6426 ftrace_number_of_groups--;
6430 void ftrace_module_enable(struct module *mod)
6432 struct dyn_ftrace *rec;
6433 struct ftrace_page *pg;
6435 mutex_lock(&ftrace_lock);
6437 if (ftrace_disabled)
6441 * If the tracing is enabled, go ahead and enable the record.
6443 * The reason not to enable the record immediately is the
6444 * inherent check of ftrace_make_nop/ftrace_make_call for
6445 * correct previous instructions. Making first the NOP
6446 * conversion puts the module to the correct state, thus
6447 * passing the ftrace_make_call check.
6449 * We also delay this to after the module code already set the
6450 * text to read-only, as we now need to set it back to read-write
6451 * so that we can modify the text.
6453 if (ftrace_start_up)
6454 ftrace_arch_code_modify_prepare();
6456 do_for_each_ftrace_rec(pg, rec) {
6459 * do_for_each_ftrace_rec() is a double loop.
6460 * module text shares the pg. If a record is
6461 * not part of this module, then skip this pg,
6462 * which the "break" will do.
6464 if (!within_module_core(rec->ip, mod) &&
6465 !within_module_init(rec->ip, mod))
6471 * When adding a module, we need to check if tracers are
6472 * currently enabled and if they are, and can trace this record,
6473 * we need to enable the module functions as well as update the
6474 * reference counts for those function records.
6476 if (ftrace_start_up)
6477 cnt += referenced_filters(rec);
6479 rec->flags &= ~FTRACE_FL_DISABLED;
6482 if (ftrace_start_up && cnt) {
6483 int failed = __ftrace_replace_code(rec, 1);
6485 ftrace_bug(failed, rec);
6490 } while_for_each_ftrace_rec();
6493 if (ftrace_start_up)
6494 ftrace_arch_code_modify_post_process();
6497 mutex_unlock(&ftrace_lock);
6499 process_cached_mods(mod->name);
6502 void ftrace_module_init(struct module *mod)
6504 if (ftrace_disabled || !mod->num_ftrace_callsites)
6507 ftrace_process_locs(mod, mod->ftrace_callsites,
6508 mod->ftrace_callsites + mod->num_ftrace_callsites);
6511 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6512 struct dyn_ftrace *rec)
6514 struct ftrace_mod_func *mod_func;
6515 unsigned long symsize;
6516 unsigned long offset;
6517 char str[KSYM_SYMBOL_LEN];
6521 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6525 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6529 mod_func->name = kstrdup(str, GFP_KERNEL);
6530 if (!mod_func->name) {
6535 mod_func->ip = rec->ip - offset;
6536 mod_func->size = symsize;
6538 mod_map->num_funcs++;
6540 list_add_rcu(&mod_func->list, &mod_map->funcs);
6543 static struct ftrace_mod_map *
6544 allocate_ftrace_mod_map(struct module *mod,
6545 unsigned long start, unsigned long end)
6547 struct ftrace_mod_map *mod_map;
6549 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6554 mod_map->start_addr = start;
6555 mod_map->end_addr = end;
6556 mod_map->num_funcs = 0;
6558 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6560 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6566 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6567 unsigned long addr, unsigned long *size,
6568 unsigned long *off, char *sym)
6570 struct ftrace_mod_func *found_func = NULL;
6571 struct ftrace_mod_func *mod_func;
6573 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6574 if (addr >= mod_func->ip &&
6575 addr < mod_func->ip + mod_func->size) {
6576 found_func = mod_func;
6583 *size = found_func->size;
6585 *off = addr - found_func->ip;
6587 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6589 return found_func->name;
6596 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6597 unsigned long *off, char **modname, char *sym)
6599 struct ftrace_mod_map *mod_map;
6600 const char *ret = NULL;
6602 /* mod_map is freed via call_rcu() */
6604 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6605 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6608 *modname = mod_map->mod->name;
6617 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6618 char *type, char *name,
6619 char *module_name, int *exported)
6621 struct ftrace_mod_map *mod_map;
6622 struct ftrace_mod_func *mod_func;
6626 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6628 if (symnum >= mod_map->num_funcs) {
6629 symnum -= mod_map->num_funcs;
6633 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6639 *value = mod_func->ip;
6641 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6642 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6650 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6651 module_name, exported);
6657 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6658 struct dyn_ftrace *rec) { }
6659 static inline struct ftrace_mod_map *
6660 allocate_ftrace_mod_map(struct module *mod,
6661 unsigned long start, unsigned long end)
6665 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6666 char *type, char *name, char *module_name,
6672 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6673 module_name, exported);
6677 #endif /* CONFIG_MODULES */
6679 struct ftrace_init_func {
6680 struct list_head list;
6684 /* Clear any init ips from hashes */
6686 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6688 struct ftrace_func_entry *entry;
6690 entry = ftrace_lookup_ip(hash, func->ip);
6692 * Do not allow this rec to match again.
6693 * Yeah, it may waste some memory, but will be removed
6694 * if/when the hash is modified again.
6701 clear_func_from_hashes(struct ftrace_init_func *func)
6703 struct trace_array *tr;
6705 mutex_lock(&trace_types_lock);
6706 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6707 if (!tr->ops || !tr->ops->func_hash)
6709 mutex_lock(&tr->ops->func_hash->regex_lock);
6710 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6711 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6712 mutex_unlock(&tr->ops->func_hash->regex_lock);
6714 mutex_unlock(&trace_types_lock);
6717 static void add_to_clear_hash_list(struct list_head *clear_list,
6718 struct dyn_ftrace *rec)
6720 struct ftrace_init_func *func;
6722 func = kmalloc(sizeof(*func), GFP_KERNEL);
6724 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6729 list_add(&func->list, clear_list);
6732 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6734 unsigned long start = (unsigned long)(start_ptr);
6735 unsigned long end = (unsigned long)(end_ptr);
6736 struct ftrace_page **last_pg = &ftrace_pages_start;
6737 struct ftrace_page *pg;
6738 struct dyn_ftrace *rec;
6739 struct dyn_ftrace key;
6740 struct ftrace_mod_map *mod_map = NULL;
6741 struct ftrace_init_func *func, *func_next;
6742 struct list_head clear_hash;
6745 INIT_LIST_HEAD(&clear_hash);
6748 key.flags = end; /* overload flags, as it is unsigned long */
6750 mutex_lock(&ftrace_lock);
6753 * If we are freeing module init memory, then check if
6754 * any tracer is active. If so, we need to save a mapping of
6755 * the module functions being freed with the address.
6757 if (mod && ftrace_ops_list != &ftrace_list_end)
6758 mod_map = allocate_ftrace_mod_map(mod, start, end);
6760 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6761 if (end < pg->records[0].ip ||
6762 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6765 rec = bsearch(&key, pg->records, pg->index,
6766 sizeof(struct dyn_ftrace),
6771 /* rec will be cleared from hashes after ftrace_lock unlock */
6772 add_to_clear_hash_list(&clear_hash, rec);
6775 save_ftrace_mod_rec(mod_map, rec);
6778 ftrace_update_tot_cnt--;
6780 *last_pg = pg->next;
6781 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6782 free_pages((unsigned long)pg->records, order);
6783 ftrace_number_of_pages -= 1 << order;
6784 ftrace_number_of_groups--;
6786 pg = container_of(last_pg, struct ftrace_page, next);
6791 memmove(rec, rec + 1,
6792 (pg->index - (rec - pg->records)) * sizeof(*rec));
6793 /* More than one function may be in this block */
6796 mutex_unlock(&ftrace_lock);
6798 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6799 clear_func_from_hashes(func);
6804 void __init ftrace_free_init_mem(void)
6806 void *start = (void *)(&__init_begin);
6807 void *end = (void *)(&__init_end);
6809 ftrace_free_mem(NULL, start, end);
6812 void __init ftrace_init(void)
6814 extern unsigned long __start_mcount_loc[];
6815 extern unsigned long __stop_mcount_loc[];
6816 unsigned long count, flags;
6819 local_irq_save(flags);
6820 ret = ftrace_dyn_arch_init();
6821 local_irq_restore(flags);
6825 count = __stop_mcount_loc - __start_mcount_loc;
6827 pr_info("ftrace: No functions to be traced?\n");
6831 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6832 count, count / ENTRIES_PER_PAGE + 1);
6834 last_ftrace_enabled = ftrace_enabled = 1;
6836 ret = ftrace_process_locs(NULL,
6840 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6841 ftrace_number_of_pages, ftrace_number_of_groups);
6843 set_ftrace_early_filters();
6847 ftrace_disabled = 1;
6850 /* Do nothing if arch does not support this */
6851 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6855 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6857 unsigned long trampoline = ops->trampoline;
6859 arch_ftrace_update_trampoline(ops);
6860 if (ops->trampoline && ops->trampoline != trampoline &&
6861 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6862 /* Add to kallsyms before the perf events */
6863 ftrace_add_trampoline_to_kallsyms(ops);
6864 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6865 ops->trampoline, ops->trampoline_size, false,
6866 FTRACE_TRAMPOLINE_SYM);
6868 * Record the perf text poke event after the ksymbol register
6871 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6872 (void *)ops->trampoline,
6873 ops->trampoline_size);
6877 void ftrace_init_trace_array(struct trace_array *tr)
6879 INIT_LIST_HEAD(&tr->func_probes);
6880 INIT_LIST_HEAD(&tr->mod_trace);
6881 INIT_LIST_HEAD(&tr->mod_notrace);
6885 struct ftrace_ops global_ops = {
6886 .func = ftrace_stub,
6887 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6888 FTRACE_OPS_FL_INITIALIZED |
6892 static int __init ftrace_nodyn_init(void)
6897 core_initcall(ftrace_nodyn_init);
6899 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6900 static inline void ftrace_startup_enable(int command) { }
6901 static inline void ftrace_startup_all(int command) { }
6903 # define ftrace_startup_sysctl() do { } while (0)
6904 # define ftrace_shutdown_sysctl() do { } while (0)
6906 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6910 #endif /* CONFIG_DYNAMIC_FTRACE */
6912 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6914 tr->ops = &global_ops;
6915 tr->ops->private = tr;
6916 ftrace_init_trace_array(tr);
6919 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6921 /* If we filter on pids, update to use the pid function */
6922 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6923 if (WARN_ON(tr->ops->func != ftrace_stub))
6924 printk("ftrace ops had %pS for function\n",
6927 tr->ops->func = func;
6928 tr->ops->private = tr;
6931 void ftrace_reset_array_ops(struct trace_array *tr)
6933 tr->ops->func = ftrace_stub;
6936 static nokprobe_inline void
6937 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6938 struct ftrace_ops *ignored, struct pt_regs *regs)
6940 struct ftrace_ops *op;
6943 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6948 * Some of the ops may be dynamically allocated,
6949 * they must be freed after a synchronize_rcu().
6951 preempt_disable_notrace();
6953 do_for_each_ftrace_op(op, ftrace_ops_list) {
6954 /* Stub functions don't need to be called nor tested */
6955 if (op->flags & FTRACE_OPS_FL_STUB)
6958 * Check the following for each ops before calling their func:
6959 * if RCU flag is set, then rcu_is_watching() must be true
6960 * if PER_CPU is set, then ftrace_function_local_disable()
6962 * Otherwise test if the ip matches the ops filter
6964 * If any of the above fails then the op->func() is not executed.
6966 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6967 ftrace_ops_test(op, ip, regs)) {
6968 if (FTRACE_WARN_ON(!op->func)) {
6969 pr_warn("op=%p %pS\n", op, op);
6972 op->func(ip, parent_ip, op, regs);
6974 } while_for_each_ftrace_op(op);
6976 preempt_enable_notrace();
6977 trace_clear_recursion(bit);
6981 * Some archs only support passing ip and parent_ip. Even though
6982 * the list function ignores the op parameter, we do not want any
6983 * C side effects, where a function is called without the caller
6984 * sending a third parameter.
6985 * Archs are to support both the regs and ftrace_ops at the same time.
6986 * If they support ftrace_ops, it is assumed they support regs.
6987 * If call backs want to use regs, they must either check for regs
6988 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6989 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6990 * An architecture can pass partial regs with ftrace_ops and still
6991 * set the ARCH_SUPPORTS_FTRACE_OPS.
6993 #if ARCH_SUPPORTS_FTRACE_OPS
6994 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6995 struct ftrace_ops *op, struct pt_regs *regs)
6997 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6999 NOKPROBE_SYMBOL(ftrace_ops_list_func);
7001 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
7003 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7005 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
7009 * If there's only one function registered but it does not support
7010 * recursion, needs RCU protection and/or requires per cpu handling, then
7011 * this function will be called by the mcount trampoline.
7013 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7014 struct ftrace_ops *op, struct pt_regs *regs)
7018 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
7022 preempt_disable_notrace();
7024 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7025 op->func(ip, parent_ip, op, regs);
7027 preempt_enable_notrace();
7028 trace_clear_recursion(bit);
7030 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7033 * ftrace_ops_get_func - get the function a trampoline should call
7034 * @ops: the ops to get the function for
7036 * Normally the mcount trampoline will call the ops->func, but there
7037 * are times that it should not. For example, if the ops does not
7038 * have its own recursion protection, then it should call the
7039 * ftrace_ops_assist_func() instead.
7041 * Returns the function that the trampoline should call for @ops.
7043 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7046 * If the function does not handle recursion, needs to be RCU safe,
7047 * or does per cpu logic, then we need to call the assist handler.
7049 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
7050 ops->flags & FTRACE_OPS_FL_RCU)
7051 return ftrace_ops_assist_func;
7057 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7058 struct task_struct *prev, struct task_struct *next)
7060 struct trace_array *tr = data;
7061 struct trace_pid_list *pid_list;
7062 struct trace_pid_list *no_pid_list;
7064 pid_list = rcu_dereference_sched(tr->function_pids);
7065 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7067 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7068 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7071 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7076 ftrace_pid_follow_sched_process_fork(void *data,
7077 struct task_struct *self,
7078 struct task_struct *task)
7080 struct trace_pid_list *pid_list;
7081 struct trace_array *tr = data;
7083 pid_list = rcu_dereference_sched(tr->function_pids);
7084 trace_filter_add_remove_task(pid_list, self, task);
7086 pid_list = rcu_dereference_sched(tr->function_no_pids);
7087 trace_filter_add_remove_task(pid_list, self, task);
7091 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7093 struct trace_pid_list *pid_list;
7094 struct trace_array *tr = data;
7096 pid_list = rcu_dereference_sched(tr->function_pids);
7097 trace_filter_add_remove_task(pid_list, NULL, task);
7099 pid_list = rcu_dereference_sched(tr->function_no_pids);
7100 trace_filter_add_remove_task(pid_list, NULL, task);
7103 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7106 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7108 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7111 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7113 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7118 static void clear_ftrace_pids(struct trace_array *tr, int type)
7120 struct trace_pid_list *pid_list;
7121 struct trace_pid_list *no_pid_list;
7124 pid_list = rcu_dereference_protected(tr->function_pids,
7125 lockdep_is_held(&ftrace_lock));
7126 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7127 lockdep_is_held(&ftrace_lock));
7129 /* Make sure there's something to do */
7130 if (!pid_type_enabled(type, pid_list, no_pid_list))
7133 /* See if the pids still need to be checked after this */
7134 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7135 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7136 for_each_possible_cpu(cpu)
7137 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7140 if (type & TRACE_PIDS)
7141 rcu_assign_pointer(tr->function_pids, NULL);
7143 if (type & TRACE_NO_PIDS)
7144 rcu_assign_pointer(tr->function_no_pids, NULL);
7146 /* Wait till all users are no longer using pid filtering */
7149 if ((type & TRACE_PIDS) && pid_list)
7150 trace_free_pid_list(pid_list);
7152 if ((type & TRACE_NO_PIDS) && no_pid_list)
7153 trace_free_pid_list(no_pid_list);
7156 void ftrace_clear_pids(struct trace_array *tr)
7158 mutex_lock(&ftrace_lock);
7160 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7162 mutex_unlock(&ftrace_lock);
7165 static void ftrace_pid_reset(struct trace_array *tr, int type)
7167 mutex_lock(&ftrace_lock);
7168 clear_ftrace_pids(tr, type);
7170 ftrace_update_pid_func();
7171 ftrace_startup_all(0);
7173 mutex_unlock(&ftrace_lock);
7176 /* Greater than any max PID */
7177 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7179 static void *fpid_start(struct seq_file *m, loff_t *pos)
7182 struct trace_pid_list *pid_list;
7183 struct trace_array *tr = m->private;
7185 mutex_lock(&ftrace_lock);
7186 rcu_read_lock_sched();
7188 pid_list = rcu_dereference_sched(tr->function_pids);
7191 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7193 return trace_pid_start(pid_list, pos);
7196 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7198 struct trace_array *tr = m->private;
7199 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7201 if (v == FTRACE_NO_PIDS) {
7205 return trace_pid_next(pid_list, v, pos);
7208 static void fpid_stop(struct seq_file *m, void *p)
7211 rcu_read_unlock_sched();
7212 mutex_unlock(&ftrace_lock);
7215 static int fpid_show(struct seq_file *m, void *v)
7217 if (v == FTRACE_NO_PIDS) {
7218 seq_puts(m, "no pid\n");
7222 return trace_pid_show(m, v);
7225 static const struct seq_operations ftrace_pid_sops = {
7226 .start = fpid_start,
7232 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7235 struct trace_pid_list *pid_list;
7236 struct trace_array *tr = m->private;
7238 mutex_lock(&ftrace_lock);
7239 rcu_read_lock_sched();
7241 pid_list = rcu_dereference_sched(tr->function_no_pids);
7244 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7246 return trace_pid_start(pid_list, pos);
7249 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7251 struct trace_array *tr = m->private;
7252 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7254 if (v == FTRACE_NO_PIDS) {
7258 return trace_pid_next(pid_list, v, pos);
7261 static const struct seq_operations ftrace_no_pid_sops = {
7262 .start = fnpid_start,
7268 static int pid_open(struct inode *inode, struct file *file, int type)
7270 const struct seq_operations *seq_ops;
7271 struct trace_array *tr = inode->i_private;
7275 ret = tracing_check_open_get_tr(tr);
7279 if ((file->f_mode & FMODE_WRITE) &&
7280 (file->f_flags & O_TRUNC))
7281 ftrace_pid_reset(tr, type);
7285 seq_ops = &ftrace_pid_sops;
7288 seq_ops = &ftrace_no_pid_sops;
7291 trace_array_put(tr);
7296 ret = seq_open(file, seq_ops);
7298 trace_array_put(tr);
7300 m = file->private_data;
7301 /* copy tr over to seq ops */
7309 ftrace_pid_open(struct inode *inode, struct file *file)
7311 return pid_open(inode, file, TRACE_PIDS);
7315 ftrace_no_pid_open(struct inode *inode, struct file *file)
7317 return pid_open(inode, file, TRACE_NO_PIDS);
7320 static void ignore_task_cpu(void *data)
7322 struct trace_array *tr = data;
7323 struct trace_pid_list *pid_list;
7324 struct trace_pid_list *no_pid_list;
7327 * This function is called by on_each_cpu() while the
7328 * event_mutex is held.
7330 pid_list = rcu_dereference_protected(tr->function_pids,
7331 mutex_is_locked(&ftrace_lock));
7332 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7333 mutex_is_locked(&ftrace_lock));
7335 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7336 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7339 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7344 pid_write(struct file *filp, const char __user *ubuf,
7345 size_t cnt, loff_t *ppos, int type)
7347 struct seq_file *m = filp->private_data;
7348 struct trace_array *tr = m->private;
7349 struct trace_pid_list *filtered_pids;
7350 struct trace_pid_list *other_pids;
7351 struct trace_pid_list *pid_list;
7357 mutex_lock(&ftrace_lock);
7361 filtered_pids = rcu_dereference_protected(tr->function_pids,
7362 lockdep_is_held(&ftrace_lock));
7363 other_pids = rcu_dereference_protected(tr->function_no_pids,
7364 lockdep_is_held(&ftrace_lock));
7367 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7368 lockdep_is_held(&ftrace_lock));
7369 other_pids = rcu_dereference_protected(tr->function_pids,
7370 lockdep_is_held(&ftrace_lock));
7378 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7384 rcu_assign_pointer(tr->function_pids, pid_list);
7387 rcu_assign_pointer(tr->function_no_pids, pid_list);
7392 if (filtered_pids) {
7394 trace_free_pid_list(filtered_pids);
7395 } else if (pid_list && !other_pids) {
7396 /* Register a probe to set whether to ignore the tracing of a task */
7397 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7401 * Ignoring of pids is done at task switch. But we have to
7402 * check for those tasks that are currently running.
7403 * Always do this in case a pid was appended or removed.
7405 on_each_cpu(ignore_task_cpu, tr, 1);
7407 ftrace_update_pid_func();
7408 ftrace_startup_all(0);
7410 mutex_unlock(&ftrace_lock);
7419 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7420 size_t cnt, loff_t *ppos)
7422 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7426 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7427 size_t cnt, loff_t *ppos)
7429 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7433 ftrace_pid_release(struct inode *inode, struct file *file)
7435 struct trace_array *tr = inode->i_private;
7437 trace_array_put(tr);
7439 return seq_release(inode, file);
7442 static const struct file_operations ftrace_pid_fops = {
7443 .open = ftrace_pid_open,
7444 .write = ftrace_pid_write,
7446 .llseek = tracing_lseek,
7447 .release = ftrace_pid_release,
7450 static const struct file_operations ftrace_no_pid_fops = {
7451 .open = ftrace_no_pid_open,
7452 .write = ftrace_no_pid_write,
7454 .llseek = tracing_lseek,
7455 .release = ftrace_pid_release,
7458 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7460 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7461 tr, &ftrace_pid_fops);
7462 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7463 tr, &ftrace_no_pid_fops);
7466 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7467 struct dentry *d_tracer)
7469 /* Only the top level directory has the dyn_tracefs and profile */
7470 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7472 ftrace_init_dyn_tracefs(d_tracer);
7473 ftrace_profile_tracefs(d_tracer);
7477 * ftrace_kill - kill ftrace
7479 * This function should be used by panic code. It stops ftrace
7480 * but in a not so nice way. If you need to simply kill ftrace
7481 * from a non-atomic section, use ftrace_kill.
7483 void ftrace_kill(void)
7485 ftrace_disabled = 1;
7487 ftrace_trace_function = ftrace_stub;
7491 * Test if ftrace is dead or not.
7493 int ftrace_is_dead(void)
7495 return ftrace_disabled;
7499 * register_ftrace_function - register a function for profiling
7500 * @ops - ops structure that holds the function for profiling.
7502 * Register a function to be called by all functions in the
7505 * Note: @ops->func and all the functions it calls must be labeled
7506 * with "notrace", otherwise it will go into a
7509 int register_ftrace_function(struct ftrace_ops *ops)
7513 ftrace_ops_init(ops);
7515 mutex_lock(&ftrace_lock);
7517 ret = ftrace_startup(ops, 0);
7519 mutex_unlock(&ftrace_lock);
7523 EXPORT_SYMBOL_GPL(register_ftrace_function);
7526 * unregister_ftrace_function - unregister a function for profiling.
7527 * @ops - ops structure that holds the function to unregister
7529 * Unregister a function that was added to be called by ftrace profiling.
7531 int unregister_ftrace_function(struct ftrace_ops *ops)
7535 mutex_lock(&ftrace_lock);
7536 ret = ftrace_shutdown(ops, 0);
7537 mutex_unlock(&ftrace_lock);
7541 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7543 static bool is_permanent_ops_registered(void)
7545 struct ftrace_ops *op;
7547 do_for_each_ftrace_op(op, ftrace_ops_list) {
7548 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7550 } while_for_each_ftrace_op(op);
7556 ftrace_enable_sysctl(struct ctl_table *table, int write,
7557 void *buffer, size_t *lenp, loff_t *ppos)
7561 mutex_lock(&ftrace_lock);
7563 if (unlikely(ftrace_disabled))
7566 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7568 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7571 if (ftrace_enabled) {
7573 /* we are starting ftrace again */
7574 if (rcu_dereference_protected(ftrace_ops_list,
7575 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7576 update_ftrace_function();
7578 ftrace_startup_sysctl();
7581 if (is_permanent_ops_registered()) {
7582 ftrace_enabled = true;
7587 /* stopping ftrace calls (just send to ftrace_stub) */
7588 ftrace_trace_function = ftrace_stub;
7590 ftrace_shutdown_sysctl();
7593 last_ftrace_enabled = !!ftrace_enabled;
7595 mutex_unlock(&ftrace_lock);