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 INIT_LIST_HEAD(&ftrace_mod->list);
1299 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1300 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1301 ftrace_mod->enable = enable;
1303 if (!ftrace_mod->func || !ftrace_mod->module)
1306 list_add(&ftrace_mod->list, mod_head);
1311 free_ftrace_mod(ftrace_mod);
1316 static struct ftrace_hash *
1317 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1319 struct ftrace_func_entry *entry;
1320 struct ftrace_hash *new_hash;
1325 new_hash = alloc_ftrace_hash(size_bits);
1330 new_hash->flags = hash->flags;
1333 if (ftrace_hash_empty(hash))
1336 size = 1 << hash->size_bits;
1337 for (i = 0; i < size; i++) {
1338 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1339 ret = add_hash_entry(new_hash, entry->ip);
1345 FTRACE_WARN_ON(new_hash->count != hash->count);
1350 free_ftrace_hash(new_hash);
1355 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1357 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1359 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1360 struct ftrace_hash *new_hash);
1362 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1364 struct ftrace_func_entry *entry;
1365 struct ftrace_hash *new_hash;
1366 struct hlist_head *hhd;
1367 struct hlist_node *tn;
1372 * Use around half the size (max bit of it), but
1373 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1375 bits = fls(size / 2);
1377 /* Don't allocate too much */
1378 if (bits > FTRACE_HASH_MAX_BITS)
1379 bits = FTRACE_HASH_MAX_BITS;
1381 new_hash = alloc_ftrace_hash(bits);
1385 new_hash->flags = src->flags;
1387 size = 1 << src->size_bits;
1388 for (i = 0; i < size; i++) {
1389 hhd = &src->buckets[i];
1390 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1391 remove_hash_entry(src, entry);
1392 __add_hash_entry(new_hash, entry);
1398 static struct ftrace_hash *
1399 __ftrace_hash_move(struct ftrace_hash *src)
1401 int size = src->count;
1404 * If the new source is empty, just return the empty_hash.
1406 if (ftrace_hash_empty(src))
1409 return dup_hash(src, size);
1413 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1414 struct ftrace_hash **dst, struct ftrace_hash *src)
1416 struct ftrace_hash *new_hash;
1419 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1420 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1423 new_hash = __ftrace_hash_move(src);
1427 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1429 /* IPMODIFY should be updated only when filter_hash updating */
1430 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1432 free_ftrace_hash(new_hash);
1438 * Remove the current set, update the hash and add
1441 ftrace_hash_rec_disable_modify(ops, enable);
1443 rcu_assign_pointer(*dst, new_hash);
1445 ftrace_hash_rec_enable_modify(ops, enable);
1450 static bool hash_contains_ip(unsigned long ip,
1451 struct ftrace_ops_hash *hash)
1454 * The function record is a match if it exists in the filter
1455 * hash and not in the notrace hash. Note, an empty hash is
1456 * considered a match for the filter hash, but an empty
1457 * notrace hash is considered not in the notrace hash.
1459 return (ftrace_hash_empty(hash->filter_hash) ||
1460 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1461 (ftrace_hash_empty(hash->notrace_hash) ||
1462 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1466 * Test the hashes for this ops to see if we want to call
1467 * the ops->func or not.
1469 * It's a match if the ip is in the ops->filter_hash or
1470 * the filter_hash does not exist or is empty,
1472 * the ip is not in the ops->notrace_hash.
1474 * This needs to be called with preemption disabled as
1475 * the hashes are freed with call_rcu().
1478 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1480 struct ftrace_ops_hash hash;
1483 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1485 * There's a small race when adding ops that the ftrace handler
1486 * that wants regs, may be called without them. We can not
1487 * allow that handler to be called if regs is NULL.
1489 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1493 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1494 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1496 if (hash_contains_ip(ip, &hash))
1505 * This is a double for. Do not use 'break' to break out of the loop,
1506 * you must use a goto.
1508 #define do_for_each_ftrace_rec(pg, rec) \
1509 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1511 for (_____i = 0; _____i < pg->index; _____i++) { \
1512 rec = &pg->records[_____i];
1514 #define while_for_each_ftrace_rec() \
1519 static int ftrace_cmp_recs(const void *a, const void *b)
1521 const struct dyn_ftrace *key = a;
1522 const struct dyn_ftrace *rec = b;
1524 if (key->flags < rec->ip)
1526 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1531 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1533 struct ftrace_page *pg;
1534 struct dyn_ftrace *rec = NULL;
1535 struct dyn_ftrace key;
1538 key.flags = end; /* overload flags, as it is unsigned long */
1540 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1541 if (pg->index == 0 ||
1542 end < pg->records[0].ip ||
1543 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1545 rec = bsearch(&key, pg->records, pg->index,
1546 sizeof(struct dyn_ftrace),
1555 * ftrace_location_range - return the first address of a traced location
1556 * if it touches the given ip range
1557 * @start: start of range to search.
1558 * @end: end of range to search (inclusive). @end points to the last byte
1561 * Returns rec->ip if the related ftrace location is a least partly within
1562 * the given address range. That is, the first address of the instruction
1563 * that is either a NOP or call to the function tracer. It checks the ftrace
1564 * internal tables to determine if the address belongs or not.
1566 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1568 struct dyn_ftrace *rec;
1570 rec = lookup_rec(start, end);
1578 * ftrace_location - return true if the ip giving is a traced location
1579 * @ip: the instruction pointer to check
1581 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1582 * That is, the instruction that is either a NOP or call to
1583 * the function tracer. It checks the ftrace internal tables to
1584 * determine if the address belongs or not.
1586 unsigned long ftrace_location(unsigned long ip)
1588 return ftrace_location_range(ip, ip);
1592 * ftrace_text_reserved - return true if range contains an ftrace location
1593 * @start: start of range to search
1594 * @end: end of range to search (inclusive). @end points to the last byte to check.
1596 * Returns 1 if @start and @end contains a ftrace location.
1597 * That is, the instruction that is either a NOP or call to
1598 * the function tracer. It checks the ftrace internal tables to
1599 * determine if the address belongs or not.
1601 int ftrace_text_reserved(const void *start, const void *end)
1605 ret = ftrace_location_range((unsigned long)start,
1606 (unsigned long)end);
1611 /* Test if ops registered to this rec needs regs */
1612 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1614 struct ftrace_ops *ops;
1615 bool keep_regs = false;
1617 for (ops = ftrace_ops_list;
1618 ops != &ftrace_list_end; ops = ops->next) {
1619 /* pass rec in as regs to have non-NULL val */
1620 if (ftrace_ops_test(ops, rec->ip, rec)) {
1621 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1631 static struct ftrace_ops *
1632 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1633 static struct ftrace_ops *
1634 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1635 static struct ftrace_ops *
1636 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1638 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1642 struct ftrace_hash *hash;
1643 struct ftrace_hash *other_hash;
1644 struct ftrace_page *pg;
1645 struct dyn_ftrace *rec;
1646 bool update = false;
1650 /* Only update if the ops has been registered */
1651 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1655 * In the filter_hash case:
1656 * If the count is zero, we update all records.
1657 * Otherwise we just update the items in the hash.
1659 * In the notrace_hash case:
1660 * We enable the update in the hash.
1661 * As disabling notrace means enabling the tracing,
1662 * and enabling notrace means disabling, the inc variable
1666 hash = ops->func_hash->filter_hash;
1667 other_hash = ops->func_hash->notrace_hash;
1668 if (ftrace_hash_empty(hash))
1672 hash = ops->func_hash->notrace_hash;
1673 other_hash = ops->func_hash->filter_hash;
1675 * If the notrace hash has no items,
1676 * then there's nothing to do.
1678 if (ftrace_hash_empty(hash))
1682 do_for_each_ftrace_rec(pg, rec) {
1683 int in_other_hash = 0;
1687 if (rec->flags & FTRACE_FL_DISABLED)
1692 * Only the filter_hash affects all records.
1693 * Update if the record is not in the notrace hash.
1695 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1698 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1699 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1702 * If filter_hash is set, we want to match all functions
1703 * that are in the hash but not in the other hash.
1705 * If filter_hash is not set, then we are decrementing.
1706 * That means we match anything that is in the hash
1707 * and also in the other_hash. That is, we need to turn
1708 * off functions in the other hash because they are disabled
1711 if (filter_hash && in_hash && !in_other_hash)
1713 else if (!filter_hash && in_hash &&
1714 (in_other_hash || ftrace_hash_empty(other_hash)))
1722 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1725 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1726 rec->flags |= FTRACE_FL_DIRECT;
1729 * If there's only a single callback registered to a
1730 * function, and the ops has a trampoline registered
1731 * for it, then we can call it directly.
1733 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1734 rec->flags |= FTRACE_FL_TRAMP;
1737 * If we are adding another function callback
1738 * to this function, and the previous had a
1739 * custom trampoline in use, then we need to go
1740 * back to the default trampoline.
1742 rec->flags &= ~FTRACE_FL_TRAMP;
1745 * If any ops wants regs saved for this function
1746 * then all ops will get saved regs.
1748 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1749 rec->flags |= FTRACE_FL_REGS;
1751 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1756 * Only the internal direct_ops should have the
1757 * DIRECT flag set. Thus, if it is removing a
1758 * function, then that function should no longer
1761 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1762 rec->flags &= ~FTRACE_FL_DIRECT;
1765 * If the rec had REGS enabled and the ops that is
1766 * being removed had REGS set, then see if there is
1767 * still any ops for this record that wants regs.
1768 * If not, we can stop recording them.
1770 if (ftrace_rec_count(rec) > 0 &&
1771 rec->flags & FTRACE_FL_REGS &&
1772 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1773 if (!test_rec_ops_needs_regs(rec))
1774 rec->flags &= ~FTRACE_FL_REGS;
1778 * The TRAMP needs to be set only if rec count
1779 * is decremented to one, and the ops that is
1780 * left has a trampoline. As TRAMP can only be
1781 * enabled if there is only a single ops attached
1784 if (ftrace_rec_count(rec) == 1 &&
1785 ftrace_find_tramp_ops_any_other(rec, ops))
1786 rec->flags |= FTRACE_FL_TRAMP;
1788 rec->flags &= ~FTRACE_FL_TRAMP;
1791 * flags will be cleared in ftrace_check_record()
1792 * if rec count is zero.
1797 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1798 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1800 /* Shortcut, if we handled all records, we are done. */
1801 if (!all && count == hash->count)
1803 } while_for_each_ftrace_rec();
1808 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1811 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1814 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1817 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1820 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1821 int filter_hash, int inc)
1823 struct ftrace_ops *op;
1825 __ftrace_hash_rec_update(ops, filter_hash, inc);
1827 if (ops->func_hash != &global_ops.local_hash)
1831 * If the ops shares the global_ops hash, then we need to update
1832 * all ops that are enabled and use this hash.
1834 do_for_each_ftrace_op(op, ftrace_ops_list) {
1838 if (op->func_hash == &global_ops.local_hash)
1839 __ftrace_hash_rec_update(op, filter_hash, inc);
1840 } while_for_each_ftrace_op(op);
1843 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1846 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1849 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1852 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1856 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1857 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1858 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1859 * Note that old_hash and new_hash has below meanings
1860 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1861 * - If the hash is EMPTY_HASH, it hits nothing
1862 * - Anything else hits the recs which match the hash entries.
1864 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1865 struct ftrace_hash *old_hash,
1866 struct ftrace_hash *new_hash)
1868 struct ftrace_page *pg;
1869 struct dyn_ftrace *rec, *end = NULL;
1872 /* Only update if the ops has been registered */
1873 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1876 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1880 * Since the IPMODIFY is a very address sensitive action, we do not
1881 * allow ftrace_ops to set all functions to new hash.
1883 if (!new_hash || !old_hash)
1886 /* Update rec->flags */
1887 do_for_each_ftrace_rec(pg, rec) {
1889 if (rec->flags & FTRACE_FL_DISABLED)
1892 /* We need to update only differences of filter_hash */
1893 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1894 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1895 if (in_old == in_new)
1899 /* New entries must ensure no others are using it */
1900 if (rec->flags & FTRACE_FL_IPMODIFY)
1902 rec->flags |= FTRACE_FL_IPMODIFY;
1903 } else /* Removed entry */
1904 rec->flags &= ~FTRACE_FL_IPMODIFY;
1905 } while_for_each_ftrace_rec();
1912 /* Roll back what we did above */
1913 do_for_each_ftrace_rec(pg, rec) {
1915 if (rec->flags & FTRACE_FL_DISABLED)
1921 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1922 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1923 if (in_old == in_new)
1927 rec->flags &= ~FTRACE_FL_IPMODIFY;
1929 rec->flags |= FTRACE_FL_IPMODIFY;
1930 } while_for_each_ftrace_rec();
1936 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1938 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1940 if (ftrace_hash_empty(hash))
1943 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1946 /* Disabling always succeeds */
1947 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1949 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1951 if (ftrace_hash_empty(hash))
1954 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1957 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1958 struct ftrace_hash *new_hash)
1960 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1962 if (ftrace_hash_empty(old_hash))
1965 if (ftrace_hash_empty(new_hash))
1968 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1971 static void print_ip_ins(const char *fmt, const unsigned char *p)
1973 char ins[MCOUNT_INSN_SIZE];
1976 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
1977 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
1981 printk(KERN_CONT "%s", fmt);
1983 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1984 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
1987 enum ftrace_bug_type ftrace_bug_type;
1988 const void *ftrace_expected;
1990 static void print_bug_type(void)
1992 switch (ftrace_bug_type) {
1993 case FTRACE_BUG_UNKNOWN:
1995 case FTRACE_BUG_INIT:
1996 pr_info("Initializing ftrace call sites\n");
1998 case FTRACE_BUG_NOP:
1999 pr_info("Setting ftrace call site to NOP\n");
2001 case FTRACE_BUG_CALL:
2002 pr_info("Setting ftrace call site to call ftrace function\n");
2004 case FTRACE_BUG_UPDATE:
2005 pr_info("Updating ftrace call site to call a different ftrace function\n");
2011 * ftrace_bug - report and shutdown function tracer
2012 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2013 * @rec: The record that failed
2015 * The arch code that enables or disables the function tracing
2016 * can call ftrace_bug() when it has detected a problem in
2017 * modifying the code. @failed should be one of either:
2018 * EFAULT - if the problem happens on reading the @ip address
2019 * EINVAL - if what is read at @ip is not what was expected
2020 * EPERM - if the problem happens on writing to the @ip address
2022 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2024 unsigned long ip = rec ? rec->ip : 0;
2026 pr_info("------------[ ftrace bug ]------------\n");
2030 pr_info("ftrace faulted on modifying ");
2031 print_ip_sym(KERN_INFO, ip);
2034 pr_info("ftrace failed to modify ");
2035 print_ip_sym(KERN_INFO, ip);
2036 print_ip_ins(" actual: ", (unsigned char *)ip);
2038 if (ftrace_expected) {
2039 print_ip_ins(" expected: ", ftrace_expected);
2044 pr_info("ftrace faulted on writing ");
2045 print_ip_sym(KERN_INFO, ip);
2048 pr_info("ftrace faulted on unknown error ");
2049 print_ip_sym(KERN_INFO, ip);
2053 struct ftrace_ops *ops = NULL;
2055 pr_info("ftrace record flags: %lx\n", rec->flags);
2056 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2057 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2058 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2059 ops = ftrace_find_tramp_ops_any(rec);
2062 pr_cont("\ttramp: %pS (%pS)",
2063 (void *)ops->trampoline,
2065 ops = ftrace_find_tramp_ops_next(rec, ops);
2068 pr_cont("\ttramp: ERROR!");
2071 ip = ftrace_get_addr_curr(rec);
2072 pr_cont("\n expected tramp: %lx\n", ip);
2075 FTRACE_WARN_ON_ONCE(1);
2078 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2080 unsigned long flag = 0UL;
2082 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2084 if (rec->flags & FTRACE_FL_DISABLED)
2085 return FTRACE_UPDATE_IGNORE;
2088 * If we are updating calls:
2090 * If the record has a ref count, then we need to enable it
2091 * because someone is using it.
2093 * Otherwise we make sure its disabled.
2095 * If we are disabling calls, then disable all records that
2098 if (enable && ftrace_rec_count(rec))
2099 flag = FTRACE_FL_ENABLED;
2102 * If enabling and the REGS flag does not match the REGS_EN, or
2103 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2104 * this record. Set flags to fail the compare against ENABLED.
2105 * Same for direct calls.
2108 if (!(rec->flags & FTRACE_FL_REGS) !=
2109 !(rec->flags & FTRACE_FL_REGS_EN))
2110 flag |= FTRACE_FL_REGS;
2112 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2113 !(rec->flags & FTRACE_FL_TRAMP_EN))
2114 flag |= FTRACE_FL_TRAMP;
2117 * Direct calls are special, as count matters.
2118 * We must test the record for direct, if the
2119 * DIRECT and DIRECT_EN do not match, but only
2120 * if the count is 1. That's because, if the
2121 * count is something other than one, we do not
2122 * want the direct enabled (it will be done via the
2123 * direct helper). But if DIRECT_EN is set, and
2124 * the count is not one, we need to clear it.
2126 if (ftrace_rec_count(rec) == 1) {
2127 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2128 !(rec->flags & FTRACE_FL_DIRECT_EN))
2129 flag |= FTRACE_FL_DIRECT;
2130 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2131 flag |= FTRACE_FL_DIRECT;
2135 /* If the state of this record hasn't changed, then do nothing */
2136 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2137 return FTRACE_UPDATE_IGNORE;
2140 /* Save off if rec is being enabled (for return value) */
2141 flag ^= rec->flags & FTRACE_FL_ENABLED;
2144 rec->flags |= FTRACE_FL_ENABLED;
2145 if (flag & FTRACE_FL_REGS) {
2146 if (rec->flags & FTRACE_FL_REGS)
2147 rec->flags |= FTRACE_FL_REGS_EN;
2149 rec->flags &= ~FTRACE_FL_REGS_EN;
2151 if (flag & FTRACE_FL_TRAMP) {
2152 if (rec->flags & FTRACE_FL_TRAMP)
2153 rec->flags |= FTRACE_FL_TRAMP_EN;
2155 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2157 if (flag & FTRACE_FL_DIRECT) {
2159 * If there's only one user (direct_ops helper)
2160 * then we can call the direct function
2161 * directly (no ftrace trampoline).
2163 if (ftrace_rec_count(rec) == 1) {
2164 if (rec->flags & FTRACE_FL_DIRECT)
2165 rec->flags |= FTRACE_FL_DIRECT_EN;
2167 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2170 * Can only call directly if there's
2171 * only one callback to the function.
2173 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2179 * If this record is being updated from a nop, then
2180 * return UPDATE_MAKE_CALL.
2182 * return UPDATE_MODIFY_CALL to tell the caller to convert
2183 * from the save regs, to a non-save regs function or
2184 * vice versa, or from a trampoline call.
2186 if (flag & FTRACE_FL_ENABLED) {
2187 ftrace_bug_type = FTRACE_BUG_CALL;
2188 return FTRACE_UPDATE_MAKE_CALL;
2191 ftrace_bug_type = FTRACE_BUG_UPDATE;
2192 return FTRACE_UPDATE_MODIFY_CALL;
2196 /* If there's no more users, clear all flags */
2197 if (!ftrace_rec_count(rec))
2201 * Just disable the record, but keep the ops TRAMP
2202 * and REGS states. The _EN flags must be disabled though.
2204 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2205 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2208 ftrace_bug_type = FTRACE_BUG_NOP;
2209 return FTRACE_UPDATE_MAKE_NOP;
2213 * ftrace_update_record, set a record that now is tracing or not
2214 * @rec: the record to update
2215 * @enable: set to true if the record is tracing, false to force disable
2217 * The records that represent all functions that can be traced need
2218 * to be updated when tracing has been enabled.
2220 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2222 return ftrace_check_record(rec, enable, true);
2226 * ftrace_test_record, check if the record has been enabled or not
2227 * @rec: the record to test
2228 * @enable: set to true to check if enabled, false if it is disabled
2230 * The arch code may need to test if a record is already set to
2231 * tracing to determine how to modify the function code that it
2234 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2236 return ftrace_check_record(rec, enable, false);
2239 static struct ftrace_ops *
2240 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2242 struct ftrace_ops *op;
2243 unsigned long ip = rec->ip;
2245 do_for_each_ftrace_op(op, ftrace_ops_list) {
2247 if (!op->trampoline)
2250 if (hash_contains_ip(ip, op->func_hash))
2252 } while_for_each_ftrace_op(op);
2257 static struct ftrace_ops *
2258 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2260 struct ftrace_ops *op;
2261 unsigned long ip = rec->ip;
2263 do_for_each_ftrace_op(op, ftrace_ops_list) {
2265 if (op == op_exclude || !op->trampoline)
2268 if (hash_contains_ip(ip, op->func_hash))
2270 } while_for_each_ftrace_op(op);
2275 static struct ftrace_ops *
2276 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2277 struct ftrace_ops *op)
2279 unsigned long ip = rec->ip;
2281 while_for_each_ftrace_op(op) {
2283 if (!op->trampoline)
2286 if (hash_contains_ip(ip, op->func_hash))
2293 static struct ftrace_ops *
2294 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2296 struct ftrace_ops *op;
2297 unsigned long ip = rec->ip;
2300 * Need to check removed ops first.
2301 * If they are being removed, and this rec has a tramp,
2302 * and this rec is in the ops list, then it would be the
2303 * one with the tramp.
2306 if (hash_contains_ip(ip, &removed_ops->old_hash))
2311 * Need to find the current trampoline for a rec.
2312 * Now, a trampoline is only attached to a rec if there
2313 * was a single 'ops' attached to it. But this can be called
2314 * when we are adding another op to the rec or removing the
2315 * current one. Thus, if the op is being added, we can
2316 * ignore it because it hasn't attached itself to the rec
2319 * If an ops is being modified (hooking to different functions)
2320 * then we don't care about the new functions that are being
2321 * added, just the old ones (that are probably being removed).
2323 * If we are adding an ops to a function that already is using
2324 * a trampoline, it needs to be removed (trampolines are only
2325 * for single ops connected), then an ops that is not being
2326 * modified also needs to be checked.
2328 do_for_each_ftrace_op(op, ftrace_ops_list) {
2330 if (!op->trampoline)
2334 * If the ops is being added, it hasn't gotten to
2335 * the point to be removed from this tree yet.
2337 if (op->flags & FTRACE_OPS_FL_ADDING)
2342 * If the ops is being modified and is in the old
2343 * hash, then it is probably being removed from this
2346 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2347 hash_contains_ip(ip, &op->old_hash))
2350 * If the ops is not being added or modified, and it's
2351 * in its normal filter hash, then this must be the one
2354 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2355 hash_contains_ip(ip, op->func_hash))
2358 } while_for_each_ftrace_op(op);
2363 static struct ftrace_ops *
2364 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2366 struct ftrace_ops *op;
2367 unsigned long ip = rec->ip;
2369 do_for_each_ftrace_op(op, ftrace_ops_list) {
2370 /* pass rec in as regs to have non-NULL val */
2371 if (hash_contains_ip(ip, op->func_hash))
2373 } while_for_each_ftrace_op(op);
2378 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2379 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2380 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2381 static DEFINE_MUTEX(direct_mutex);
2382 int ftrace_direct_func_count;
2385 * Search the direct_functions hash to see if the given instruction pointer
2386 * has a direct caller attached to it.
2388 unsigned long ftrace_find_rec_direct(unsigned long ip)
2390 struct ftrace_func_entry *entry;
2392 entry = __ftrace_lookup_ip(direct_functions, ip);
2396 return entry->direct;
2399 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2400 struct ftrace_ops *ops, struct pt_regs *regs)
2404 addr = ftrace_find_rec_direct(ip);
2408 arch_ftrace_set_direct_caller(regs, addr);
2411 struct ftrace_ops direct_ops = {
2412 .func = call_direct_funcs,
2413 .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
2414 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2415 | FTRACE_OPS_FL_PERMANENT,
2417 * By declaring the main trampoline as this trampoline
2418 * it will never have one allocated for it. Allocated
2419 * trampolines should not call direct functions.
2420 * The direct_ops should only be called by the builtin
2421 * ftrace_regs_caller trampoline.
2423 .trampoline = FTRACE_REGS_ADDR,
2425 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2428 * ftrace_get_addr_new - Get the call address to set to
2429 * @rec: The ftrace record descriptor
2431 * If the record has the FTRACE_FL_REGS set, that means that it
2432 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2433 * is not set, then it wants to convert to the normal callback.
2435 * Returns the address of the trampoline to set to
2437 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2439 struct ftrace_ops *ops;
2442 if ((rec->flags & FTRACE_FL_DIRECT) &&
2443 (ftrace_rec_count(rec) == 1)) {
2444 addr = ftrace_find_rec_direct(rec->ip);
2450 /* Trampolines take precedence over regs */
2451 if (rec->flags & FTRACE_FL_TRAMP) {
2452 ops = ftrace_find_tramp_ops_new(rec);
2453 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2454 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2455 (void *)rec->ip, (void *)rec->ip, rec->flags);
2456 /* Ftrace is shutting down, return anything */
2457 return (unsigned long)FTRACE_ADDR;
2459 return ops->trampoline;
2462 if (rec->flags & FTRACE_FL_REGS)
2463 return (unsigned long)FTRACE_REGS_ADDR;
2465 return (unsigned long)FTRACE_ADDR;
2469 * ftrace_get_addr_curr - Get the call address that is already there
2470 * @rec: The ftrace record descriptor
2472 * The FTRACE_FL_REGS_EN is set when the record already points to
2473 * a function that saves all the regs. Basically the '_EN' version
2474 * represents the current state of the function.
2476 * Returns the address of the trampoline that is currently being called
2478 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2480 struct ftrace_ops *ops;
2483 /* Direct calls take precedence over trampolines */
2484 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2485 addr = ftrace_find_rec_direct(rec->ip);
2491 /* Trampolines take precedence over regs */
2492 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2493 ops = ftrace_find_tramp_ops_curr(rec);
2494 if (FTRACE_WARN_ON(!ops)) {
2495 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2496 (void *)rec->ip, (void *)rec->ip);
2497 /* Ftrace is shutting down, return anything */
2498 return (unsigned long)FTRACE_ADDR;
2500 return ops->trampoline;
2503 if (rec->flags & FTRACE_FL_REGS_EN)
2504 return (unsigned long)FTRACE_REGS_ADDR;
2506 return (unsigned long)FTRACE_ADDR;
2510 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2512 unsigned long ftrace_old_addr;
2513 unsigned long ftrace_addr;
2516 ftrace_addr = ftrace_get_addr_new(rec);
2518 /* This needs to be done before we call ftrace_update_record */
2519 ftrace_old_addr = ftrace_get_addr_curr(rec);
2521 ret = ftrace_update_record(rec, enable);
2523 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2526 case FTRACE_UPDATE_IGNORE:
2529 case FTRACE_UPDATE_MAKE_CALL:
2530 ftrace_bug_type = FTRACE_BUG_CALL;
2531 return ftrace_make_call(rec, ftrace_addr);
2533 case FTRACE_UPDATE_MAKE_NOP:
2534 ftrace_bug_type = FTRACE_BUG_NOP;
2535 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2537 case FTRACE_UPDATE_MODIFY_CALL:
2538 ftrace_bug_type = FTRACE_BUG_UPDATE;
2539 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2542 return -1; /* unknown ftrace bug */
2545 void __weak ftrace_replace_code(int mod_flags)
2547 struct dyn_ftrace *rec;
2548 struct ftrace_page *pg;
2549 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2550 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2553 if (unlikely(ftrace_disabled))
2556 do_for_each_ftrace_rec(pg, rec) {
2558 if (rec->flags & FTRACE_FL_DISABLED)
2561 failed = __ftrace_replace_code(rec, enable);
2563 ftrace_bug(failed, rec);
2564 /* Stop processing */
2569 } while_for_each_ftrace_rec();
2572 struct ftrace_rec_iter {
2573 struct ftrace_page *pg;
2578 * ftrace_rec_iter_start, start up iterating over traced functions
2580 * Returns an iterator handle that is used to iterate over all
2581 * the records that represent address locations where functions
2584 * May return NULL if no records are available.
2586 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2589 * We only use a single iterator.
2590 * Protected by the ftrace_lock mutex.
2592 static struct ftrace_rec_iter ftrace_rec_iter;
2593 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2595 iter->pg = ftrace_pages_start;
2598 /* Could have empty pages */
2599 while (iter->pg && !iter->pg->index)
2600 iter->pg = iter->pg->next;
2609 * ftrace_rec_iter_next, get the next record to process.
2610 * @iter: The handle to the iterator.
2612 * Returns the next iterator after the given iterator @iter.
2614 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2618 if (iter->index >= iter->pg->index) {
2619 iter->pg = iter->pg->next;
2622 /* Could have empty pages */
2623 while (iter->pg && !iter->pg->index)
2624 iter->pg = iter->pg->next;
2634 * ftrace_rec_iter_record, get the record at the iterator location
2635 * @iter: The current iterator location
2637 * Returns the record that the current @iter is at.
2639 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2641 return &iter->pg->records[iter->index];
2645 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2649 if (unlikely(ftrace_disabled))
2652 ret = ftrace_init_nop(mod, rec);
2654 ftrace_bug_type = FTRACE_BUG_INIT;
2655 ftrace_bug(ret, rec);
2662 * archs can override this function if they must do something
2663 * before the modifying code is performed.
2665 int __weak ftrace_arch_code_modify_prepare(void)
2671 * archs can override this function if they must do something
2672 * after the modifying code is performed.
2674 int __weak ftrace_arch_code_modify_post_process(void)
2679 void ftrace_modify_all_code(int command)
2681 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2685 if (command & FTRACE_MAY_SLEEP)
2686 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2689 * If the ftrace_caller calls a ftrace_ops func directly,
2690 * we need to make sure that it only traces functions it
2691 * expects to trace. When doing the switch of functions,
2692 * we need to update to the ftrace_ops_list_func first
2693 * before the transition between old and new calls are set,
2694 * as the ftrace_ops_list_func will check the ops hashes
2695 * to make sure the ops are having the right functions
2699 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2700 if (FTRACE_WARN_ON(err))
2704 if (command & FTRACE_UPDATE_CALLS)
2705 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2706 else if (command & FTRACE_DISABLE_CALLS)
2707 ftrace_replace_code(mod_flags);
2709 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2710 function_trace_op = set_function_trace_op;
2712 /* If irqs are disabled, we are in stop machine */
2713 if (!irqs_disabled())
2714 smp_call_function(ftrace_sync_ipi, NULL, 1);
2715 err = ftrace_update_ftrace_func(ftrace_trace_function);
2716 if (FTRACE_WARN_ON(err))
2720 if (command & FTRACE_START_FUNC_RET)
2721 err = ftrace_enable_ftrace_graph_caller();
2722 else if (command & FTRACE_STOP_FUNC_RET)
2723 err = ftrace_disable_ftrace_graph_caller();
2724 FTRACE_WARN_ON(err);
2727 static int __ftrace_modify_code(void *data)
2729 int *command = data;
2731 ftrace_modify_all_code(*command);
2737 * ftrace_run_stop_machine, go back to the stop machine method
2738 * @command: The command to tell ftrace what to do
2740 * If an arch needs to fall back to the stop machine method, the
2741 * it can call this function.
2743 void ftrace_run_stop_machine(int command)
2745 stop_machine(__ftrace_modify_code, &command, NULL);
2749 * arch_ftrace_update_code, modify the code to trace or not trace
2750 * @command: The command that needs to be done
2752 * Archs can override this function if it does not need to
2753 * run stop_machine() to modify code.
2755 void __weak arch_ftrace_update_code(int command)
2757 ftrace_run_stop_machine(command);
2760 static void ftrace_run_update_code(int command)
2764 ret = ftrace_arch_code_modify_prepare();
2765 FTRACE_WARN_ON(ret);
2770 * By default we use stop_machine() to modify the code.
2771 * But archs can do what ever they want as long as it
2772 * is safe. The stop_machine() is the safest, but also
2773 * produces the most overhead.
2775 arch_ftrace_update_code(command);
2777 ret = ftrace_arch_code_modify_post_process();
2778 FTRACE_WARN_ON(ret);
2781 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2782 struct ftrace_ops_hash *old_hash)
2784 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2785 ops->old_hash.filter_hash = old_hash->filter_hash;
2786 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2787 ftrace_run_update_code(command);
2788 ops->old_hash.filter_hash = NULL;
2789 ops->old_hash.notrace_hash = NULL;
2790 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2793 static ftrace_func_t saved_ftrace_func;
2794 static int ftrace_start_up;
2796 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2800 /* List of trace_ops that have allocated trampolines */
2801 static LIST_HEAD(ftrace_ops_trampoline_list);
2803 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2805 lockdep_assert_held(&ftrace_lock);
2806 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2809 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2811 lockdep_assert_held(&ftrace_lock);
2812 list_del_rcu(&ops->list);
2817 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2818 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2821 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2822 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2824 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2826 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2829 * Record the text poke event before the ksymbol unregister
2832 perf_event_text_poke((void *)ops->trampoline,
2833 (void *)ops->trampoline,
2834 ops->trampoline_size, NULL, 0);
2835 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2836 ops->trampoline, ops->trampoline_size,
2837 true, FTRACE_TRAMPOLINE_SYM);
2838 /* Remove from kallsyms after the perf events */
2839 ftrace_remove_trampoline_from_kallsyms(ops);
2842 arch_ftrace_trampoline_free(ops);
2845 static void ftrace_startup_enable(int command)
2847 if (saved_ftrace_func != ftrace_trace_function) {
2848 saved_ftrace_func = ftrace_trace_function;
2849 command |= FTRACE_UPDATE_TRACE_FUNC;
2852 if (!command || !ftrace_enabled)
2855 ftrace_run_update_code(command);
2858 static void ftrace_startup_all(int command)
2860 update_all_ops = true;
2861 ftrace_startup_enable(command);
2862 update_all_ops = false;
2865 int ftrace_startup(struct ftrace_ops *ops, int command)
2869 if (unlikely(ftrace_disabled))
2872 ret = __register_ftrace_function(ops);
2879 * Note that ftrace probes uses this to start up
2880 * and modify functions it will probe. But we still
2881 * set the ADDING flag for modification, as probes
2882 * do not have trampolines. If they add them in the
2883 * future, then the probes will need to distinguish
2884 * between adding and updating probes.
2886 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2888 ret = ftrace_hash_ipmodify_enable(ops);
2890 /* Rollback registration process */
2891 __unregister_ftrace_function(ops);
2893 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2894 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2895 ftrace_trampoline_free(ops);
2899 if (ftrace_hash_rec_enable(ops, 1))
2900 command |= FTRACE_UPDATE_CALLS;
2902 ftrace_startup_enable(command);
2905 * If ftrace is in an undefined state, we just remove ops from list
2906 * to prevent the NULL pointer, instead of totally rolling it back and
2907 * free trampoline, because those actions could cause further damage.
2909 if (unlikely(ftrace_disabled)) {
2910 __unregister_ftrace_function(ops);
2914 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2919 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2923 if (unlikely(ftrace_disabled))
2926 ret = __unregister_ftrace_function(ops);
2932 * Just warn in case of unbalance, no need to kill ftrace, it's not
2933 * critical but the ftrace_call callers may be never nopped again after
2934 * further ftrace uses.
2936 WARN_ON_ONCE(ftrace_start_up < 0);
2938 /* Disabling ipmodify never fails */
2939 ftrace_hash_ipmodify_disable(ops);
2941 if (ftrace_hash_rec_disable(ops, 1))
2942 command |= FTRACE_UPDATE_CALLS;
2944 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2946 if (saved_ftrace_func != ftrace_trace_function) {
2947 saved_ftrace_func = ftrace_trace_function;
2948 command |= FTRACE_UPDATE_TRACE_FUNC;
2951 if (!command || !ftrace_enabled)
2955 * If the ops uses a trampoline, then it needs to be
2956 * tested first on update.
2958 ops->flags |= FTRACE_OPS_FL_REMOVING;
2961 /* The trampoline logic checks the old hashes */
2962 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2963 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2965 ftrace_run_update_code(command);
2968 * If there's no more ops registered with ftrace, run a
2969 * sanity check to make sure all rec flags are cleared.
2971 if (rcu_dereference_protected(ftrace_ops_list,
2972 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2973 struct ftrace_page *pg;
2974 struct dyn_ftrace *rec;
2976 do_for_each_ftrace_rec(pg, rec) {
2977 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2978 pr_warn(" %pS flags:%lx\n",
2979 (void *)rec->ip, rec->flags);
2980 } while_for_each_ftrace_rec();
2983 ops->old_hash.filter_hash = NULL;
2984 ops->old_hash.notrace_hash = NULL;
2987 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2991 * Dynamic ops may be freed, we must make sure that all
2992 * callers are done before leaving this function.
2993 * The same goes for freeing the per_cpu data of the per_cpu
2996 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2998 * We need to do a hard force of sched synchronization.
2999 * This is because we use preempt_disable() to do RCU, but
3000 * the function tracers can be called where RCU is not watching
3001 * (like before user_exit()). We can not rely on the RCU
3002 * infrastructure to do the synchronization, thus we must do it
3005 synchronize_rcu_tasks_rude();
3008 * When the kernel is preemptive, tasks can be preempted
3009 * while on a ftrace trampoline. Just scheduling a task on
3010 * a CPU is not good enough to flush them. Calling
3011 * synchornize_rcu_tasks() will wait for those tasks to
3012 * execute and either schedule voluntarily or enter user space.
3014 if (IS_ENABLED(CONFIG_PREEMPTION))
3015 synchronize_rcu_tasks();
3017 ftrace_trampoline_free(ops);
3023 static void ftrace_startup_sysctl(void)
3027 if (unlikely(ftrace_disabled))
3030 /* Force update next time */
3031 saved_ftrace_func = NULL;
3032 /* ftrace_start_up is true if we want ftrace running */
3033 if (ftrace_start_up) {
3034 command = FTRACE_UPDATE_CALLS;
3035 if (ftrace_graph_active)
3036 command |= FTRACE_START_FUNC_RET;
3037 ftrace_startup_enable(command);
3041 static void ftrace_shutdown_sysctl(void)
3045 if (unlikely(ftrace_disabled))
3048 /* ftrace_start_up is true if ftrace is running */
3049 if (ftrace_start_up) {
3050 command = FTRACE_DISABLE_CALLS;
3051 if (ftrace_graph_active)
3052 command |= FTRACE_STOP_FUNC_RET;
3053 ftrace_run_update_code(command);
3057 static u64 ftrace_update_time;
3058 unsigned long ftrace_update_tot_cnt;
3059 unsigned long ftrace_number_of_pages;
3060 unsigned long ftrace_number_of_groups;
3062 static inline int ops_traces_mod(struct ftrace_ops *ops)
3065 * Filter_hash being empty will default to trace module.
3066 * But notrace hash requires a test of individual module functions.
3068 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3069 ftrace_hash_empty(ops->func_hash->notrace_hash);
3073 * Check if the current ops references the record.
3075 * If the ops traces all functions, then it was already accounted for.
3076 * If the ops does not trace the current record function, skip it.
3077 * If the ops ignores the function via notrace filter, skip it.
3080 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3082 /* If ops isn't enabled, ignore it */
3083 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3086 /* If ops traces all then it includes this function */
3087 if (ops_traces_mod(ops))
3090 /* The function must be in the filter */
3091 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3092 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3095 /* If in notrace hash, we ignore it too */
3096 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3102 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3104 struct ftrace_page *pg;
3105 struct dyn_ftrace *p;
3107 unsigned long update_cnt = 0;
3108 unsigned long rec_flags = 0;
3111 start = ftrace_now(raw_smp_processor_id());
3114 * When a module is loaded, this function is called to convert
3115 * the calls to mcount in its text to nops, and also to create
3116 * an entry in the ftrace data. Now, if ftrace is activated
3117 * after this call, but before the module sets its text to
3118 * read-only, the modification of enabling ftrace can fail if
3119 * the read-only is done while ftrace is converting the calls.
3120 * To prevent this, the module's records are set as disabled
3121 * and will be enabled after the call to set the module's text
3125 rec_flags |= FTRACE_FL_DISABLED;
3127 for (pg = new_pgs; pg; pg = pg->next) {
3129 for (i = 0; i < pg->index; i++) {
3131 /* If something went wrong, bail without enabling anything */
3132 if (unlikely(ftrace_disabled))
3135 p = &pg->records[i];
3136 p->flags = rec_flags;
3139 * Do the initial record conversion from mcount jump
3140 * to the NOP instructions.
3142 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3143 !ftrace_nop_initialize(mod, p))
3150 stop = ftrace_now(raw_smp_processor_id());
3151 ftrace_update_time = stop - start;
3152 ftrace_update_tot_cnt += update_cnt;
3157 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3163 if (WARN_ON(!count))
3166 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3167 order = get_count_order(pages);
3170 * We want to fill as much as possible. No more than a page
3173 if (!is_power_of_2(pages))
3177 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3180 /* if we can't allocate this size, try something smaller */
3187 ftrace_number_of_pages += 1 << order;
3188 ftrace_number_of_groups++;
3190 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3199 static void ftrace_free_pages(struct ftrace_page *pages)
3201 struct ftrace_page *pg = pages;
3205 free_pages((unsigned long)pg->records, pg->order);
3206 ftrace_number_of_pages -= 1 << pg->order;
3211 ftrace_number_of_groups--;
3215 static struct ftrace_page *
3216 ftrace_allocate_pages(unsigned long num_to_init)
3218 struct ftrace_page *start_pg;
3219 struct ftrace_page *pg;
3225 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3230 * Try to allocate as much as possible in one continues
3231 * location that fills in all of the space. We want to
3232 * waste as little space as possible.
3235 cnt = ftrace_allocate_records(pg, num_to_init);
3243 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3253 ftrace_free_pages(start_pg);
3254 pr_info("ftrace: FAILED to allocate memory for functions\n");
3258 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3260 struct ftrace_iterator {
3264 struct ftrace_page *pg;
3265 struct dyn_ftrace *func;
3266 struct ftrace_func_probe *probe;
3267 struct ftrace_func_entry *probe_entry;
3268 struct trace_parser parser;
3269 struct ftrace_hash *hash;
3270 struct ftrace_ops *ops;
3271 struct trace_array *tr;
3272 struct list_head *mod_list;
3279 t_probe_next(struct seq_file *m, loff_t *pos)
3281 struct ftrace_iterator *iter = m->private;
3282 struct trace_array *tr = iter->ops->private;
3283 struct list_head *func_probes;
3284 struct ftrace_hash *hash;
3285 struct list_head *next;
3286 struct hlist_node *hnd = NULL;
3287 struct hlist_head *hhd;
3296 func_probes = &tr->func_probes;
3297 if (list_empty(func_probes))
3301 next = func_probes->next;
3302 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3305 if (iter->probe_entry)
3306 hnd = &iter->probe_entry->hlist;
3308 hash = iter->probe->ops.func_hash->filter_hash;
3311 * A probe being registered may temporarily have an empty hash
3312 * and it's at the end of the func_probes list.
3314 if (!hash || hash == EMPTY_HASH)
3317 size = 1 << hash->size_bits;
3320 if (iter->pidx >= size) {
3321 if (iter->probe->list.next == func_probes)
3323 next = iter->probe->list.next;
3324 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3325 hash = iter->probe->ops.func_hash->filter_hash;
3326 size = 1 << hash->size_bits;
3330 hhd = &hash->buckets[iter->pidx];
3332 if (hlist_empty(hhd)) {
3348 if (WARN_ON_ONCE(!hnd))
3351 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3356 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3358 struct ftrace_iterator *iter = m->private;
3362 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3365 if (iter->mod_pos > *pos)
3369 iter->probe_entry = NULL;
3371 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3372 p = t_probe_next(m, &l);
3379 /* Only set this if we have an item */
3380 iter->flags |= FTRACE_ITER_PROBE;
3386 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3388 struct ftrace_func_entry *probe_entry;
3389 struct ftrace_probe_ops *probe_ops;
3390 struct ftrace_func_probe *probe;
3392 probe = iter->probe;
3393 probe_entry = iter->probe_entry;
3395 if (WARN_ON_ONCE(!probe || !probe_entry))
3398 probe_ops = probe->probe_ops;
3400 if (probe_ops->print)
3401 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3403 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3404 (void *)probe_ops->func);
3410 t_mod_next(struct seq_file *m, loff_t *pos)
3412 struct ftrace_iterator *iter = m->private;
3413 struct trace_array *tr = iter->tr;
3418 iter->mod_list = iter->mod_list->next;
3420 if (iter->mod_list == &tr->mod_trace ||
3421 iter->mod_list == &tr->mod_notrace) {
3422 iter->flags &= ~FTRACE_ITER_MOD;
3426 iter->mod_pos = *pos;
3431 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3433 struct ftrace_iterator *iter = m->private;
3437 if (iter->func_pos > *pos)
3440 iter->mod_pos = iter->func_pos;
3442 /* probes are only available if tr is set */
3446 for (l = 0; l <= (*pos - iter->func_pos); ) {
3447 p = t_mod_next(m, &l);
3452 iter->flags &= ~FTRACE_ITER_MOD;
3453 return t_probe_start(m, pos);
3456 /* Only set this if we have an item */
3457 iter->flags |= FTRACE_ITER_MOD;
3463 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3465 struct ftrace_mod_load *ftrace_mod;
3466 struct trace_array *tr = iter->tr;
3468 if (WARN_ON_ONCE(!iter->mod_list) ||
3469 iter->mod_list == &tr->mod_trace ||
3470 iter->mod_list == &tr->mod_notrace)
3473 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3475 if (ftrace_mod->func)
3476 seq_printf(m, "%s", ftrace_mod->func);
3480 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3486 t_func_next(struct seq_file *m, loff_t *pos)
3488 struct ftrace_iterator *iter = m->private;
3489 struct dyn_ftrace *rec = NULL;
3494 if (iter->idx >= iter->pg->index) {
3495 if (iter->pg->next) {
3496 iter->pg = iter->pg->next;
3501 rec = &iter->pg->records[iter->idx++];
3502 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3503 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3505 ((iter->flags & FTRACE_ITER_ENABLED) &&
3506 !(rec->flags & FTRACE_FL_ENABLED))) {
3516 iter->pos = iter->func_pos = *pos;
3523 t_next(struct seq_file *m, void *v, loff_t *pos)
3525 struct ftrace_iterator *iter = m->private;
3526 loff_t l = *pos; /* t_probe_start() must use original pos */
3529 if (unlikely(ftrace_disabled))
3532 if (iter->flags & FTRACE_ITER_PROBE)
3533 return t_probe_next(m, pos);
3535 if (iter->flags & FTRACE_ITER_MOD)
3536 return t_mod_next(m, pos);
3538 if (iter->flags & FTRACE_ITER_PRINTALL) {
3539 /* next must increment pos, and t_probe_start does not */
3541 return t_mod_start(m, &l);
3544 ret = t_func_next(m, pos);
3547 return t_mod_start(m, &l);
3552 static void reset_iter_read(struct ftrace_iterator *iter)
3556 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3559 static void *t_start(struct seq_file *m, loff_t *pos)
3561 struct ftrace_iterator *iter = m->private;
3565 mutex_lock(&ftrace_lock);
3567 if (unlikely(ftrace_disabled))
3571 * If an lseek was done, then reset and start from beginning.
3573 if (*pos < iter->pos)
3574 reset_iter_read(iter);
3577 * For set_ftrace_filter reading, if we have the filter
3578 * off, we can short cut and just print out that all
3579 * functions are enabled.
3581 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3582 ftrace_hash_empty(iter->hash)) {
3583 iter->func_pos = 1; /* Account for the message */
3585 return t_mod_start(m, pos);
3586 iter->flags |= FTRACE_ITER_PRINTALL;
3587 /* reset in case of seek/pread */
3588 iter->flags &= ~FTRACE_ITER_PROBE;
3592 if (iter->flags & FTRACE_ITER_MOD)
3593 return t_mod_start(m, pos);
3596 * Unfortunately, we need to restart at ftrace_pages_start
3597 * every time we let go of the ftrace_mutex. This is because
3598 * those pointers can change without the lock.
3600 iter->pg = ftrace_pages_start;
3602 for (l = 0; l <= *pos; ) {
3603 p = t_func_next(m, &l);
3609 return t_mod_start(m, pos);
3614 static void t_stop(struct seq_file *m, void *p)
3616 mutex_unlock(&ftrace_lock);
3620 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3625 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3626 struct dyn_ftrace *rec)
3630 ptr = arch_ftrace_trampoline_func(ops, rec);
3632 seq_printf(m, " ->%pS", ptr);
3635 static int t_show(struct seq_file *m, void *v)
3637 struct ftrace_iterator *iter = m->private;
3638 struct dyn_ftrace *rec;
3640 if (iter->flags & FTRACE_ITER_PROBE)
3641 return t_probe_show(m, iter);
3643 if (iter->flags & FTRACE_ITER_MOD)
3644 return t_mod_show(m, iter);
3646 if (iter->flags & FTRACE_ITER_PRINTALL) {
3647 if (iter->flags & FTRACE_ITER_NOTRACE)
3648 seq_puts(m, "#### no functions disabled ####\n");
3650 seq_puts(m, "#### all functions enabled ####\n");
3659 seq_printf(m, "%ps", (void *)rec->ip);
3660 if (iter->flags & FTRACE_ITER_ENABLED) {
3661 struct ftrace_ops *ops;
3663 seq_printf(m, " (%ld)%s%s%s",
3664 ftrace_rec_count(rec),
3665 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3666 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3667 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3668 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3669 ops = ftrace_find_tramp_ops_any(rec);
3672 seq_printf(m, "\ttramp: %pS (%pS)",
3673 (void *)ops->trampoline,
3675 add_trampoline_func(m, ops, rec);
3676 ops = ftrace_find_tramp_ops_next(rec, ops);
3679 seq_puts(m, "\ttramp: ERROR!");
3681 add_trampoline_func(m, NULL, rec);
3683 if (rec->flags & FTRACE_FL_DIRECT) {
3684 unsigned long direct;
3686 direct = ftrace_find_rec_direct(rec->ip);
3688 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3697 static const struct seq_operations show_ftrace_seq_ops = {
3705 ftrace_avail_open(struct inode *inode, struct file *file)
3707 struct ftrace_iterator *iter;
3710 ret = security_locked_down(LOCKDOWN_TRACEFS);
3714 if (unlikely(ftrace_disabled))
3717 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3721 iter->pg = ftrace_pages_start;
3722 iter->ops = &global_ops;
3728 ftrace_enabled_open(struct inode *inode, struct file *file)
3730 struct ftrace_iterator *iter;
3733 * This shows us what functions are currently being
3734 * traced and by what. Not sure if we want lockdown
3735 * to hide such critical information for an admin.
3736 * Although, perhaps it can show information we don't
3737 * want people to see, but if something is tracing
3738 * something, we probably want to know about it.
3741 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3745 iter->pg = ftrace_pages_start;
3746 iter->flags = FTRACE_ITER_ENABLED;
3747 iter->ops = &global_ops;
3753 * ftrace_regex_open - initialize function tracer filter files
3754 * @ops: The ftrace_ops that hold the hash filters
3755 * @flag: The type of filter to process
3756 * @inode: The inode, usually passed in to your open routine
3757 * @file: The file, usually passed in to your open routine
3759 * ftrace_regex_open() initializes the filter files for the
3760 * @ops. Depending on @flag it may process the filter hash or
3761 * the notrace hash of @ops. With this called from the open
3762 * routine, you can use ftrace_filter_write() for the write
3763 * routine if @flag has FTRACE_ITER_FILTER set, or
3764 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3765 * tracing_lseek() should be used as the lseek routine, and
3766 * release must call ftrace_regex_release().
3769 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3770 struct inode *inode, struct file *file)
3772 struct ftrace_iterator *iter;
3773 struct ftrace_hash *hash;
3774 struct list_head *mod_head;
3775 struct trace_array *tr = ops->private;
3778 ftrace_ops_init(ops);
3780 if (unlikely(ftrace_disabled))
3783 if (tracing_check_open_get_tr(tr))
3786 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3790 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3797 mutex_lock(&ops->func_hash->regex_lock);
3799 if (flag & FTRACE_ITER_NOTRACE) {
3800 hash = ops->func_hash->notrace_hash;
3801 mod_head = tr ? &tr->mod_notrace : NULL;
3803 hash = ops->func_hash->filter_hash;
3804 mod_head = tr ? &tr->mod_trace : NULL;
3807 iter->mod_list = mod_head;
3809 if (file->f_mode & FMODE_WRITE) {
3810 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3812 if (file->f_flags & O_TRUNC) {
3813 iter->hash = alloc_ftrace_hash(size_bits);
3814 clear_ftrace_mod_list(mod_head);
3816 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3820 trace_parser_put(&iter->parser);
3828 if (file->f_mode & FMODE_READ) {
3829 iter->pg = ftrace_pages_start;
3831 ret = seq_open(file, &show_ftrace_seq_ops);
3833 struct seq_file *m = file->private_data;
3837 free_ftrace_hash(iter->hash);
3838 trace_parser_put(&iter->parser);
3841 file->private_data = iter;
3844 mutex_unlock(&ops->func_hash->regex_lock);
3850 trace_array_put(tr);
3857 ftrace_filter_open(struct inode *inode, struct file *file)
3859 struct ftrace_ops *ops = inode->i_private;
3861 /* Checks for tracefs lockdown */
3862 return ftrace_regex_open(ops,
3863 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3868 ftrace_notrace_open(struct inode *inode, struct file *file)
3870 struct ftrace_ops *ops = inode->i_private;
3872 /* Checks for tracefs lockdown */
3873 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3877 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3878 struct ftrace_glob {
3885 * If symbols in an architecture don't correspond exactly to the user-visible
3886 * name of what they represent, it is possible to define this function to
3887 * perform the necessary adjustments.
3889 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3894 static int ftrace_match(char *str, struct ftrace_glob *g)
3899 str = arch_ftrace_match_adjust(str, g->search);
3903 if (strcmp(str, g->search) == 0)
3906 case MATCH_FRONT_ONLY:
3907 if (strncmp(str, g->search, g->len) == 0)
3910 case MATCH_MIDDLE_ONLY:
3911 if (strstr(str, g->search))
3914 case MATCH_END_ONLY:
3916 if (slen >= g->len &&
3917 memcmp(str + slen - g->len, g->search, g->len) == 0)
3921 if (glob_match(g->search, str))
3930 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3932 struct ftrace_func_entry *entry;
3935 entry = ftrace_lookup_ip(hash, rec->ip);
3937 /* Do nothing if it doesn't exist */
3941 free_hash_entry(hash, entry);
3943 /* Do nothing if it exists */
3947 ret = add_hash_entry(hash, rec->ip);
3953 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3956 long index = simple_strtoul(func_g->search, NULL, 0);
3957 struct ftrace_page *pg;
3958 struct dyn_ftrace *rec;
3960 /* The index starts at 1 */
3964 do_for_each_ftrace_rec(pg, rec) {
3965 if (pg->index <= index) {
3967 /* this is a double loop, break goes to the next page */
3970 rec = &pg->records[index];
3971 enter_record(hash, rec, clear_filter);
3973 } while_for_each_ftrace_rec();
3978 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3979 struct ftrace_glob *mod_g, int exclude_mod)
3981 char str[KSYM_SYMBOL_LEN];
3984 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3987 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3989 /* blank module name to match all modules */
3991 /* blank module globbing: modname xor exclude_mod */
3992 if (!exclude_mod != !modname)
3998 * exclude_mod is set to trace everything but the given
3999 * module. If it is set and the module matches, then
4000 * return 0. If it is not set, and the module doesn't match
4001 * also return 0. Otherwise, check the function to see if
4004 if (!mod_matches == !exclude_mod)
4007 /* blank search means to match all funcs in the mod */
4012 return ftrace_match(str, func_g);
4016 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4018 struct ftrace_page *pg;
4019 struct dyn_ftrace *rec;
4020 struct ftrace_glob func_g = { .type = MATCH_FULL };
4021 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4022 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4023 int exclude_mod = 0;
4026 int clear_filter = 0;
4029 func_g.type = filter_parse_regex(func, len, &func_g.search,
4031 func_g.len = strlen(func_g.search);
4035 mod_g.type = filter_parse_regex(mod, strlen(mod),
4036 &mod_g.search, &exclude_mod);
4037 mod_g.len = strlen(mod_g.search);
4040 mutex_lock(&ftrace_lock);
4042 if (unlikely(ftrace_disabled))
4045 if (func_g.type == MATCH_INDEX) {
4046 found = add_rec_by_index(hash, &func_g, clear_filter);
4050 do_for_each_ftrace_rec(pg, rec) {
4052 if (rec->flags & FTRACE_FL_DISABLED)
4055 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4056 ret = enter_record(hash, rec, clear_filter);
4063 } while_for_each_ftrace_rec();
4065 mutex_unlock(&ftrace_lock);
4071 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4073 return match_records(hash, buff, len, NULL);
4076 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4077 struct ftrace_ops_hash *old_hash)
4079 struct ftrace_ops *op;
4081 if (!ftrace_enabled)
4084 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4085 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4090 * If this is the shared global_ops filter, then we need to
4091 * check if there is another ops that shares it, is enabled.
4092 * If so, we still need to run the modify code.
4094 if (ops->func_hash != &global_ops.local_hash)
4097 do_for_each_ftrace_op(op, ftrace_ops_list) {
4098 if (op->func_hash == &global_ops.local_hash &&
4099 op->flags & FTRACE_OPS_FL_ENABLED) {
4100 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4101 /* Only need to do this once */
4104 } while_for_each_ftrace_op(op);
4107 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4108 struct ftrace_hash **orig_hash,
4109 struct ftrace_hash *hash,
4112 struct ftrace_ops_hash old_hash_ops;
4113 struct ftrace_hash *old_hash;
4116 old_hash = *orig_hash;
4117 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4118 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4119 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4121 ftrace_ops_update_code(ops, &old_hash_ops);
4122 free_ftrace_hash_rcu(old_hash);
4127 static bool module_exists(const char *module)
4129 /* All modules have the symbol __this_module */
4130 static const char this_mod[] = "__this_module";
4131 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4135 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4137 if (n > sizeof(modname) - 1)
4140 val = module_kallsyms_lookup_name(modname);
4144 static int cache_mod(struct trace_array *tr,
4145 const char *func, char *module, int enable)
4147 struct ftrace_mod_load *ftrace_mod, *n;
4148 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4151 mutex_lock(&ftrace_lock);
4153 /* We do not cache inverse filters */
4154 if (func[0] == '!') {
4158 /* Look to remove this hash */
4159 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4160 if (strcmp(ftrace_mod->module, module) != 0)
4163 /* no func matches all */
4164 if (strcmp(func, "*") == 0 ||
4165 (ftrace_mod->func &&
4166 strcmp(ftrace_mod->func, func) == 0)) {
4168 free_ftrace_mod(ftrace_mod);
4176 /* We only care about modules that have not been loaded yet */
4177 if (module_exists(module))
4180 /* Save this string off, and execute it when the module is loaded */
4181 ret = ftrace_add_mod(tr, func, module, enable);
4183 mutex_unlock(&ftrace_lock);
4189 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4190 int reset, int enable);
4192 #ifdef CONFIG_MODULES
4193 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4194 char *mod, bool enable)
4196 struct ftrace_mod_load *ftrace_mod, *n;
4197 struct ftrace_hash **orig_hash, *new_hash;
4198 LIST_HEAD(process_mods);
4202 mutex_lock(&ops->func_hash->regex_lock);
4205 orig_hash = &ops->func_hash->filter_hash;
4207 orig_hash = &ops->func_hash->notrace_hash;
4209 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4212 goto out; /* warn? */
4214 mutex_lock(&ftrace_lock);
4216 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4218 if (strcmp(ftrace_mod->module, mod) != 0)
4221 if (ftrace_mod->func)
4222 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4224 func = kstrdup("*", GFP_KERNEL);
4226 if (!func) /* warn? */
4229 list_del(&ftrace_mod->list);
4230 list_add(&ftrace_mod->list, &process_mods);
4232 /* Use the newly allocated func, as it may be "*" */
4233 kfree(ftrace_mod->func);
4234 ftrace_mod->func = func;
4237 mutex_unlock(&ftrace_lock);
4239 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4241 func = ftrace_mod->func;
4243 /* Grabs ftrace_lock, which is why we have this extra step */
4244 match_records(new_hash, func, strlen(func), mod);
4245 free_ftrace_mod(ftrace_mod);
4248 if (enable && list_empty(head))
4249 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4251 mutex_lock(&ftrace_lock);
4253 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4255 mutex_unlock(&ftrace_lock);
4258 mutex_unlock(&ops->func_hash->regex_lock);
4260 free_ftrace_hash(new_hash);
4263 static void process_cached_mods(const char *mod_name)
4265 struct trace_array *tr;
4268 mod = kstrdup(mod_name, GFP_KERNEL);
4272 mutex_lock(&trace_types_lock);
4273 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4274 if (!list_empty(&tr->mod_trace))
4275 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4276 if (!list_empty(&tr->mod_notrace))
4277 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4279 mutex_unlock(&trace_types_lock);
4286 * We register the module command as a template to show others how
4287 * to register the a command as well.
4291 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4292 char *func_orig, char *cmd, char *module, int enable)
4297 /* match_records() modifies func, and we need the original */
4298 func = kstrdup(func_orig, GFP_KERNEL);
4303 * cmd == 'mod' because we only registered this func
4304 * for the 'mod' ftrace_func_command.
4305 * But if you register one func with multiple commands,
4306 * you can tell which command was used by the cmd
4309 ret = match_records(hash, func, strlen(func), module);
4313 return cache_mod(tr, func_orig, module, enable);
4319 static struct ftrace_func_command ftrace_mod_cmd = {
4321 .func = ftrace_mod_callback,
4324 static int __init ftrace_mod_cmd_init(void)
4326 return register_ftrace_command(&ftrace_mod_cmd);
4328 core_initcall(ftrace_mod_cmd_init);
4330 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4331 struct ftrace_ops *op, struct pt_regs *pt_regs)
4333 struct ftrace_probe_ops *probe_ops;
4334 struct ftrace_func_probe *probe;
4336 probe = container_of(op, struct ftrace_func_probe, ops);
4337 probe_ops = probe->probe_ops;
4340 * Disable preemption for these calls to prevent a RCU grace
4341 * period. This syncs the hash iteration and freeing of items
4342 * on the hash. rcu_read_lock is too dangerous here.
4344 preempt_disable_notrace();
4345 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4346 preempt_enable_notrace();
4349 struct ftrace_func_map {
4350 struct ftrace_func_entry entry;
4354 struct ftrace_func_mapper {
4355 struct ftrace_hash hash;
4359 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4361 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4363 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4365 struct ftrace_hash *hash;
4368 * The mapper is simply a ftrace_hash, but since the entries
4369 * in the hash are not ftrace_func_entry type, we define it
4370 * as a separate structure.
4372 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4373 return (struct ftrace_func_mapper *)hash;
4377 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4378 * @mapper: The mapper that has the ip maps
4379 * @ip: the instruction pointer to find the data for
4381 * Returns the data mapped to @ip if found otherwise NULL. The return
4382 * is actually the address of the mapper data pointer. The address is
4383 * returned for use cases where the data is no bigger than a long, and
4384 * the user can use the data pointer as its data instead of having to
4385 * allocate more memory for the reference.
4387 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4390 struct ftrace_func_entry *entry;
4391 struct ftrace_func_map *map;
4393 entry = ftrace_lookup_ip(&mapper->hash, ip);
4397 map = (struct ftrace_func_map *)entry;
4402 * ftrace_func_mapper_add_ip - Map some data to an ip
4403 * @mapper: The mapper that has the ip maps
4404 * @ip: The instruction pointer address to map @data to
4405 * @data: The data to map to @ip
4407 * Returns 0 on success otherwise an error.
4409 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4410 unsigned long ip, void *data)
4412 struct ftrace_func_entry *entry;
4413 struct ftrace_func_map *map;
4415 entry = ftrace_lookup_ip(&mapper->hash, ip);
4419 map = kmalloc(sizeof(*map), GFP_KERNEL);
4426 __add_hash_entry(&mapper->hash, &map->entry);
4432 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4433 * @mapper: The mapper that has the ip maps
4434 * @ip: The instruction pointer address to remove the data from
4436 * Returns the data if it is found, otherwise NULL.
4437 * Note, if the data pointer is used as the data itself, (see
4438 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4439 * if the data pointer was set to zero.
4441 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4444 struct ftrace_func_entry *entry;
4445 struct ftrace_func_map *map;
4448 entry = ftrace_lookup_ip(&mapper->hash, ip);
4452 map = (struct ftrace_func_map *)entry;
4455 remove_hash_entry(&mapper->hash, entry);
4462 * free_ftrace_func_mapper - free a mapping of ips and data
4463 * @mapper: The mapper that has the ip maps
4464 * @free_func: A function to be called on each data item.
4466 * This is used to free the function mapper. The @free_func is optional
4467 * and can be used if the data needs to be freed as well.
4469 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4470 ftrace_mapper_func free_func)
4472 struct ftrace_func_entry *entry;
4473 struct ftrace_func_map *map;
4474 struct hlist_head *hhd;
4480 if (free_func && mapper->hash.count) {
4481 size = 1 << mapper->hash.size_bits;
4482 for (i = 0; i < size; i++) {
4483 hhd = &mapper->hash.buckets[i];
4484 hlist_for_each_entry(entry, hhd, hlist) {
4485 map = (struct ftrace_func_map *)entry;
4490 free_ftrace_hash(&mapper->hash);
4493 static void release_probe(struct ftrace_func_probe *probe)
4495 struct ftrace_probe_ops *probe_ops;
4497 mutex_lock(&ftrace_lock);
4499 WARN_ON(probe->ref <= 0);
4501 /* Subtract the ref that was used to protect this instance */
4505 probe_ops = probe->probe_ops;
4507 * Sending zero as ip tells probe_ops to free
4508 * the probe->data itself
4510 if (probe_ops->free)
4511 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4512 list_del(&probe->list);
4515 mutex_unlock(&ftrace_lock);
4518 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4521 * Add one ref to keep it from being freed when releasing the
4522 * ftrace_lock mutex.
4528 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4529 struct ftrace_probe_ops *probe_ops,
4532 struct ftrace_func_entry *entry;
4533 struct ftrace_func_probe *probe;
4534 struct ftrace_hash **orig_hash;
4535 struct ftrace_hash *old_hash;
4536 struct ftrace_hash *hash;
4545 /* We do not support '!' for function probes */
4546 if (WARN_ON(glob[0] == '!'))
4550 mutex_lock(&ftrace_lock);
4551 /* Check if the probe_ops is already registered */
4552 list_for_each_entry(probe, &tr->func_probes, list) {
4553 if (probe->probe_ops == probe_ops)
4556 if (&probe->list == &tr->func_probes) {
4557 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4559 mutex_unlock(&ftrace_lock);
4562 probe->probe_ops = probe_ops;
4563 probe->ops.func = function_trace_probe_call;
4565 ftrace_ops_init(&probe->ops);
4566 list_add(&probe->list, &tr->func_probes);
4569 acquire_probe_locked(probe);
4571 mutex_unlock(&ftrace_lock);
4574 * Note, there's a small window here that the func_hash->filter_hash
4575 * may be NULL or empty. Need to be careful when reading the loop.
4577 mutex_lock(&probe->ops.func_hash->regex_lock);
4579 orig_hash = &probe->ops.func_hash->filter_hash;
4580 old_hash = *orig_hash;
4581 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4588 ret = ftrace_match_records(hash, glob, strlen(glob));
4590 /* Nothing found? */
4597 size = 1 << hash->size_bits;
4598 for (i = 0; i < size; i++) {
4599 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4600 if (ftrace_lookup_ip(old_hash, entry->ip))
4603 * The caller might want to do something special
4604 * for each function we find. We call the callback
4605 * to give the caller an opportunity to do so.
4607 if (probe_ops->init) {
4608 ret = probe_ops->init(probe_ops, tr,
4612 if (probe_ops->free && count)
4613 probe_ops->free(probe_ops, tr,
4623 mutex_lock(&ftrace_lock);
4626 /* Nothing was added? */
4631 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4636 /* One ref for each new function traced */
4637 probe->ref += count;
4639 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4640 ret = ftrace_startup(&probe->ops, 0);
4643 mutex_unlock(&ftrace_lock);
4648 mutex_unlock(&probe->ops.func_hash->regex_lock);
4649 free_ftrace_hash(hash);
4651 release_probe(probe);
4656 if (!probe_ops->free || !count)
4659 /* Failed to do the move, need to call the free functions */
4660 for (i = 0; i < size; i++) {
4661 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4662 if (ftrace_lookup_ip(old_hash, entry->ip))
4664 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4671 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4672 struct ftrace_probe_ops *probe_ops)
4674 struct ftrace_ops_hash old_hash_ops;
4675 struct ftrace_func_entry *entry;
4676 struct ftrace_func_probe *probe;
4677 struct ftrace_glob func_g;
4678 struct ftrace_hash **orig_hash;
4679 struct ftrace_hash *old_hash;
4680 struct ftrace_hash *hash = NULL;
4681 struct hlist_node *tmp;
4682 struct hlist_head hhd;
4683 char str[KSYM_SYMBOL_LEN];
4685 int i, ret = -ENODEV;
4688 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4689 func_g.search = NULL;
4693 func_g.type = filter_parse_regex(glob, strlen(glob),
4694 &func_g.search, ¬);
4695 func_g.len = strlen(func_g.search);
4697 /* we do not support '!' for function probes */
4702 mutex_lock(&ftrace_lock);
4703 /* Check if the probe_ops is already registered */
4704 list_for_each_entry(probe, &tr->func_probes, list) {
4705 if (probe->probe_ops == probe_ops)
4708 if (&probe->list == &tr->func_probes)
4709 goto err_unlock_ftrace;
4712 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4713 goto err_unlock_ftrace;
4715 acquire_probe_locked(probe);
4717 mutex_unlock(&ftrace_lock);
4719 mutex_lock(&probe->ops.func_hash->regex_lock);
4721 orig_hash = &probe->ops.func_hash->filter_hash;
4722 old_hash = *orig_hash;
4724 if (ftrace_hash_empty(old_hash))
4727 old_hash_ops.filter_hash = old_hash;
4728 /* Probes only have filters */
4729 old_hash_ops.notrace_hash = NULL;
4732 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4736 INIT_HLIST_HEAD(&hhd);
4738 size = 1 << hash->size_bits;
4739 for (i = 0; i < size; i++) {
4740 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4742 if (func_g.search) {
4743 kallsyms_lookup(entry->ip, NULL, NULL,
4745 if (!ftrace_match(str, &func_g))
4749 remove_hash_entry(hash, entry);
4750 hlist_add_head(&entry->hlist, &hhd);
4754 /* Nothing found? */
4760 mutex_lock(&ftrace_lock);
4762 WARN_ON(probe->ref < count);
4764 probe->ref -= count;
4766 if (ftrace_hash_empty(hash))
4767 ftrace_shutdown(&probe->ops, 0);
4769 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4772 /* still need to update the function call sites */
4773 if (ftrace_enabled && !ftrace_hash_empty(hash))
4774 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4778 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4779 hlist_del(&entry->hlist);
4780 if (probe_ops->free)
4781 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4784 mutex_unlock(&ftrace_lock);
4787 mutex_unlock(&probe->ops.func_hash->regex_lock);
4788 free_ftrace_hash(hash);
4790 release_probe(probe);
4795 mutex_unlock(&ftrace_lock);
4799 void clear_ftrace_function_probes(struct trace_array *tr)
4801 struct ftrace_func_probe *probe, *n;
4803 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4804 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4807 static LIST_HEAD(ftrace_commands);
4808 static DEFINE_MUTEX(ftrace_cmd_mutex);
4811 * Currently we only register ftrace commands from __init, so mark this
4814 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4816 struct ftrace_func_command *p;
4819 mutex_lock(&ftrace_cmd_mutex);
4820 list_for_each_entry(p, &ftrace_commands, list) {
4821 if (strcmp(cmd->name, p->name) == 0) {
4826 list_add(&cmd->list, &ftrace_commands);
4828 mutex_unlock(&ftrace_cmd_mutex);
4834 * Currently we only unregister ftrace commands from __init, so mark
4837 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4839 struct ftrace_func_command *p, *n;
4842 mutex_lock(&ftrace_cmd_mutex);
4843 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4844 if (strcmp(cmd->name, p->name) == 0) {
4846 list_del_init(&p->list);
4851 mutex_unlock(&ftrace_cmd_mutex);
4856 static int ftrace_process_regex(struct ftrace_iterator *iter,
4857 char *buff, int len, int enable)
4859 struct ftrace_hash *hash = iter->hash;
4860 struct trace_array *tr = iter->ops->private;
4861 char *func, *command, *next = buff;
4862 struct ftrace_func_command *p;
4865 func = strsep(&next, ":");
4868 ret = ftrace_match_records(hash, func, len);
4878 command = strsep(&next, ":");
4880 mutex_lock(&ftrace_cmd_mutex);
4881 list_for_each_entry(p, &ftrace_commands, list) {
4882 if (strcmp(p->name, command) == 0) {
4883 ret = p->func(tr, hash, func, command, next, enable);
4888 mutex_unlock(&ftrace_cmd_mutex);
4894 ftrace_regex_write(struct file *file, const char __user *ubuf,
4895 size_t cnt, loff_t *ppos, int enable)
4897 struct ftrace_iterator *iter;
4898 struct trace_parser *parser;
4904 if (file->f_mode & FMODE_READ) {
4905 struct seq_file *m = file->private_data;
4908 iter = file->private_data;
4910 if (unlikely(ftrace_disabled))
4913 /* iter->hash is a local copy, so we don't need regex_lock */
4915 parser = &iter->parser;
4916 read = trace_get_user(parser, ubuf, cnt, ppos);
4918 if (read >= 0 && trace_parser_loaded(parser) &&
4919 !trace_parser_cont(parser)) {
4920 ret = ftrace_process_regex(iter, parser->buffer,
4921 parser->idx, enable);
4922 trace_parser_clear(parser);
4933 ftrace_filter_write(struct file *file, const char __user *ubuf,
4934 size_t cnt, loff_t *ppos)
4936 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4940 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4941 size_t cnt, loff_t *ppos)
4943 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4947 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4949 struct ftrace_func_entry *entry;
4951 if (!ftrace_location(ip))
4955 entry = ftrace_lookup_ip(hash, ip);
4958 free_hash_entry(hash, entry);
4962 return add_hash_entry(hash, ip);
4966 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4967 unsigned long ip, int remove, int reset, int enable)
4969 struct ftrace_hash **orig_hash;
4970 struct ftrace_hash *hash;
4973 if (unlikely(ftrace_disabled))
4976 mutex_lock(&ops->func_hash->regex_lock);
4979 orig_hash = &ops->func_hash->filter_hash;
4981 orig_hash = &ops->func_hash->notrace_hash;
4984 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4986 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4990 goto out_regex_unlock;
4993 if (buf && !ftrace_match_records(hash, buf, len)) {
4995 goto out_regex_unlock;
4998 ret = ftrace_match_addr(hash, ip, remove);
5000 goto out_regex_unlock;
5003 mutex_lock(&ftrace_lock);
5004 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5005 mutex_unlock(&ftrace_lock);
5008 mutex_unlock(&ops->func_hash->regex_lock);
5010 free_ftrace_hash(hash);
5015 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
5016 int reset, int enable)
5018 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
5021 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5023 struct ftrace_direct_func {
5024 struct list_head next;
5029 static LIST_HEAD(ftrace_direct_funcs);
5032 * ftrace_find_direct_func - test an address if it is a registered direct caller
5033 * @addr: The address of a registered direct caller
5035 * This searches to see if a ftrace direct caller has been registered
5036 * at a specific address, and if so, it returns a descriptor for it.
5038 * This can be used by architecture code to see if an address is
5039 * a direct caller (trampoline) attached to a fentry/mcount location.
5040 * This is useful for the function_graph tracer, as it may need to
5041 * do adjustments if it traced a location that also has a direct
5042 * trampoline attached to it.
5044 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5046 struct ftrace_direct_func *entry;
5049 /* May be called by fgraph trampoline (protected by rcu tasks) */
5050 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5051 if (entry->addr == addr) {
5062 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5064 struct ftrace_direct_func *direct;
5066 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5069 direct->addr = addr;
5071 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5072 ftrace_direct_func_count++;
5077 * register_ftrace_direct - Call a custom trampoline directly
5078 * @ip: The address of the nop at the beginning of a function
5079 * @addr: The address of the trampoline to call at @ip
5081 * This is used to connect a direct call from the nop location (@ip)
5082 * at the start of ftrace traced functions. The location that it calls
5083 * (@addr) must be able to handle a direct call, and save the parameters
5084 * of the function being traced, and restore them (or inject new ones
5085 * if needed), before returning.
5089 * -EBUSY - Another direct function is already attached (there can be only one)
5090 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5091 * -ENOMEM - There was an allocation failure.
5093 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5095 struct ftrace_direct_func *direct;
5096 struct ftrace_func_entry *entry;
5097 struct ftrace_hash *free_hash = NULL;
5098 struct dyn_ftrace *rec;
5101 mutex_lock(&direct_mutex);
5103 /* See if there's a direct function at @ip already */
5104 if (ftrace_find_rec_direct(ip))
5108 rec = lookup_rec(ip, ip);
5113 * Check if the rec says it has a direct call but we didn't
5116 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5119 /* Make sure the ip points to the exact record */
5120 if (ip != rec->ip) {
5122 /* Need to check this ip for a direct. */
5123 if (ftrace_find_rec_direct(ip))
5128 if (ftrace_hash_empty(direct_functions) ||
5129 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5130 struct ftrace_hash *new_hash;
5131 int size = ftrace_hash_empty(direct_functions) ? 0 :
5132 direct_functions->count + 1;
5137 new_hash = dup_hash(direct_functions, size);
5141 free_hash = direct_functions;
5142 direct_functions = new_hash;
5145 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5149 direct = ftrace_find_direct_func(addr);
5151 direct = ftrace_alloc_direct_func(addr);
5159 entry->direct = addr;
5160 __add_hash_entry(direct_functions, entry);
5162 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5164 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5165 ret = register_ftrace_function(&direct_ops);
5167 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5171 remove_hash_entry(direct_functions, entry);
5173 if (!direct->count) {
5174 list_del_rcu(&direct->next);
5175 synchronize_rcu_tasks();
5178 free_ftrace_hash(free_hash);
5180 ftrace_direct_func_count--;
5186 mutex_unlock(&direct_mutex);
5189 synchronize_rcu_tasks();
5190 free_ftrace_hash(free_hash);
5195 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5197 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5198 struct dyn_ftrace **recp)
5200 struct ftrace_func_entry *entry;
5201 struct dyn_ftrace *rec;
5203 rec = lookup_rec(*ip, *ip);
5207 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5209 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5213 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5215 /* Passed in ip just needs to be on the call site */
5224 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5226 struct ftrace_direct_func *direct;
5227 struct ftrace_func_entry *entry;
5230 mutex_lock(&direct_mutex);
5232 entry = find_direct_entry(&ip, NULL);
5236 if (direct_functions->count == 1)
5237 unregister_ftrace_function(&direct_ops);
5239 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5243 remove_hash_entry(direct_functions, entry);
5245 direct = ftrace_find_direct_func(addr);
5246 if (!WARN_ON(!direct)) {
5247 /* This is the good path (see the ! before WARN) */
5249 WARN_ON(direct->count < 0);
5250 if (!direct->count) {
5251 list_del_rcu(&direct->next);
5252 synchronize_rcu_tasks();
5255 ftrace_direct_func_count--;
5259 mutex_unlock(&direct_mutex);
5263 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5265 static struct ftrace_ops stub_ops = {
5266 .func = ftrace_stub,
5270 * ftrace_modify_direct_caller - modify ftrace nop directly
5271 * @entry: The ftrace hash entry of the direct helper for @rec
5272 * @rec: The record representing the function site to patch
5273 * @old_addr: The location that the site at @rec->ip currently calls
5274 * @new_addr: The location that the site at @rec->ip should call
5276 * An architecture may overwrite this function to optimize the
5277 * changing of the direct callback on an ftrace nop location.
5278 * This is called with the ftrace_lock mutex held, and no other
5279 * ftrace callbacks are on the associated record (@rec). Thus,
5280 * it is safe to modify the ftrace record, where it should be
5281 * currently calling @old_addr directly, to call @new_addr.
5283 * Safety checks should be made to make sure that the code at
5284 * @rec->ip is currently calling @old_addr. And this must
5285 * also update entry->direct to @new_addr.
5287 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5288 struct dyn_ftrace *rec,
5289 unsigned long old_addr,
5290 unsigned long new_addr)
5292 unsigned long ip = rec->ip;
5296 * The ftrace_lock was used to determine if the record
5297 * had more than one registered user to it. If it did,
5298 * we needed to prevent that from changing to do the quick
5299 * switch. But if it did not (only a direct caller was attached)
5300 * then this function is called. But this function can deal
5301 * with attached callers to the rec that we care about, and
5302 * since this function uses standard ftrace calls that take
5303 * the ftrace_lock mutex, we need to release it.
5305 mutex_unlock(&ftrace_lock);
5308 * By setting a stub function at the same address, we force
5309 * the code to call the iterator and the direct_ops helper.
5310 * This means that @ip does not call the direct call, and
5311 * we can simply modify it.
5313 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5317 ret = register_ftrace_function(&stub_ops);
5319 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5323 entry->direct = new_addr;
5326 * By removing the stub, we put back the direct call, calling
5329 unregister_ftrace_function(&stub_ops);
5330 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5333 mutex_lock(&ftrace_lock);
5339 * modify_ftrace_direct - Modify an existing direct call to call something else
5340 * @ip: The instruction pointer to modify
5341 * @old_addr: The address that the current @ip calls directly
5342 * @new_addr: The address that the @ip should call
5344 * This modifies a ftrace direct caller at an instruction pointer without
5345 * having to disable it first. The direct call will switch over to the
5346 * @new_addr without missing anything.
5348 * Returns: zero on success. Non zero on error, which includes:
5349 * -ENODEV : the @ip given has no direct caller attached
5350 * -EINVAL : the @old_addr does not match the current direct caller
5352 int modify_ftrace_direct(unsigned long ip,
5353 unsigned long old_addr, unsigned long new_addr)
5355 struct ftrace_direct_func *direct, *new_direct = NULL;
5356 struct ftrace_func_entry *entry;
5357 struct dyn_ftrace *rec;
5360 mutex_lock(&direct_mutex);
5362 mutex_lock(&ftrace_lock);
5363 entry = find_direct_entry(&ip, &rec);
5368 if (entry->direct != old_addr)
5371 direct = ftrace_find_direct_func(old_addr);
5372 if (WARN_ON(!direct))
5374 if (direct->count > 1) {
5376 new_direct = ftrace_alloc_direct_func(new_addr);
5380 new_direct->count++;
5382 direct->addr = new_addr;
5386 * If there's no other ftrace callback on the rec->ip location,
5387 * then it can be changed directly by the architecture.
5388 * If there is another caller, then we just need to change the
5389 * direct caller helper to point to @new_addr.
5391 if (ftrace_rec_count(rec) == 1) {
5392 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5394 entry->direct = new_addr;
5399 direct->addr = old_addr;
5400 if (unlikely(new_direct)) {
5402 list_del_rcu(&new_direct->next);
5403 synchronize_rcu_tasks();
5405 ftrace_direct_func_count--;
5410 mutex_unlock(&ftrace_lock);
5411 mutex_unlock(&direct_mutex);
5414 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5415 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5418 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5419 * @ops - the ops to set the filter with
5420 * @ip - the address to add to or remove from the filter.
5421 * @remove - non zero to remove the ip from the filter
5422 * @reset - non zero to reset all filters before applying this filter.
5424 * Filters denote which functions should be enabled when tracing is enabled
5425 * If @ip is NULL, it failes to update filter.
5427 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5428 int remove, int reset)
5430 ftrace_ops_init(ops);
5431 return ftrace_set_addr(ops, ip, remove, reset, 1);
5433 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5436 * ftrace_ops_set_global_filter - setup ops to use global filters
5437 * @ops - the ops which will use the global filters
5439 * ftrace users who need global function trace filtering should call this.
5440 * It can set the global filter only if ops were not initialized before.
5442 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5444 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5447 ftrace_ops_init(ops);
5448 ops->func_hash = &global_ops.local_hash;
5450 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5453 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5454 int reset, int enable)
5456 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5460 * ftrace_set_filter - set a function to filter on in ftrace
5461 * @ops - the ops to set the filter with
5462 * @buf - the string that holds the function filter text.
5463 * @len - the length of the string.
5464 * @reset - non zero to reset all filters before applying this filter.
5466 * Filters denote which functions should be enabled when tracing is enabled.
5467 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5469 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5472 ftrace_ops_init(ops);
5473 return ftrace_set_regex(ops, buf, len, reset, 1);
5475 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5478 * ftrace_set_notrace - set a function to not trace in ftrace
5479 * @ops - the ops to set the notrace filter with
5480 * @buf - the string that holds the function notrace text.
5481 * @len - the length of the string.
5482 * @reset - non zero to reset all filters before applying this filter.
5484 * Notrace Filters denote which functions should not be enabled when tracing
5485 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5488 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5491 ftrace_ops_init(ops);
5492 return ftrace_set_regex(ops, buf, len, reset, 0);
5494 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5496 * ftrace_set_global_filter - set a function to filter on with global tracers
5497 * @buf - the string that holds the function filter text.
5498 * @len - the length of the string.
5499 * @reset - non zero to reset all filters before applying this filter.
5501 * Filters denote which functions should be enabled when tracing is enabled.
5502 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5504 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5506 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5508 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5511 * ftrace_set_global_notrace - set a function to not trace with global tracers
5512 * @buf - the string that holds the function notrace text.
5513 * @len - the length of the string.
5514 * @reset - non zero to reset all filters before applying this filter.
5516 * Notrace Filters denote which functions should not be enabled when tracing
5517 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5520 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5522 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5524 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5527 * command line interface to allow users to set filters on boot up.
5529 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5530 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5531 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5533 /* Used by function selftest to not test if filter is set */
5534 bool ftrace_filter_param __initdata;
5536 static int __init set_ftrace_notrace(char *str)
5538 ftrace_filter_param = true;
5539 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5542 __setup("ftrace_notrace=", set_ftrace_notrace);
5544 static int __init set_ftrace_filter(char *str)
5546 ftrace_filter_param = true;
5547 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5550 __setup("ftrace_filter=", set_ftrace_filter);
5552 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5553 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5554 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5555 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5557 static int __init set_graph_function(char *str)
5559 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5562 __setup("ftrace_graph_filter=", set_graph_function);
5564 static int __init set_graph_notrace_function(char *str)
5566 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5569 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5571 static int __init set_graph_max_depth_function(char *str)
5575 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5578 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5580 static void __init set_ftrace_early_graph(char *buf, int enable)
5584 struct ftrace_hash *hash;
5586 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5587 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5591 func = strsep(&buf, ",");
5592 /* we allow only one expression at a time */
5593 ret = ftrace_graph_set_hash(hash, func);
5595 printk(KERN_DEBUG "ftrace: function %s not "
5596 "traceable\n", func);
5600 ftrace_graph_hash = hash;
5602 ftrace_graph_notrace_hash = hash;
5604 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5607 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5611 ftrace_ops_init(ops);
5614 func = strsep(&buf, ",");
5615 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5619 static void __init set_ftrace_early_filters(void)
5621 if (ftrace_filter_buf[0])
5622 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5623 if (ftrace_notrace_buf[0])
5624 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5625 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5626 if (ftrace_graph_buf[0])
5627 set_ftrace_early_graph(ftrace_graph_buf, 1);
5628 if (ftrace_graph_notrace_buf[0])
5629 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5630 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5633 int ftrace_regex_release(struct inode *inode, struct file *file)
5635 struct seq_file *m = (struct seq_file *)file->private_data;
5636 struct ftrace_iterator *iter;
5637 struct ftrace_hash **orig_hash;
5638 struct trace_parser *parser;
5642 if (file->f_mode & FMODE_READ) {
5644 seq_release(inode, file);
5646 iter = file->private_data;
5648 parser = &iter->parser;
5649 if (trace_parser_loaded(parser)) {
5650 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5652 ftrace_process_regex(iter, parser->buffer,
5653 parser->idx, enable);
5656 trace_parser_put(parser);
5658 mutex_lock(&iter->ops->func_hash->regex_lock);
5660 if (file->f_mode & FMODE_WRITE) {
5661 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5664 orig_hash = &iter->ops->func_hash->filter_hash;
5666 if (list_empty(&iter->tr->mod_trace))
5667 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5669 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5672 orig_hash = &iter->ops->func_hash->notrace_hash;
5674 mutex_lock(&ftrace_lock);
5675 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5676 iter->hash, filter_hash);
5677 mutex_unlock(&ftrace_lock);
5679 /* For read only, the hash is the ops hash */
5683 mutex_unlock(&iter->ops->func_hash->regex_lock);
5684 free_ftrace_hash(iter->hash);
5686 trace_array_put(iter->tr);
5692 static const struct file_operations ftrace_avail_fops = {
5693 .open = ftrace_avail_open,
5695 .llseek = seq_lseek,
5696 .release = seq_release_private,
5699 static const struct file_operations ftrace_enabled_fops = {
5700 .open = ftrace_enabled_open,
5702 .llseek = seq_lseek,
5703 .release = seq_release_private,
5706 static const struct file_operations ftrace_filter_fops = {
5707 .open = ftrace_filter_open,
5709 .write = ftrace_filter_write,
5710 .llseek = tracing_lseek,
5711 .release = ftrace_regex_release,
5714 static const struct file_operations ftrace_notrace_fops = {
5715 .open = ftrace_notrace_open,
5717 .write = ftrace_notrace_write,
5718 .llseek = tracing_lseek,
5719 .release = ftrace_regex_release,
5722 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5724 static DEFINE_MUTEX(graph_lock);
5726 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5727 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5729 enum graph_filter_type {
5730 GRAPH_FILTER_NOTRACE = 0,
5731 GRAPH_FILTER_FUNCTION,
5734 #define FTRACE_GRAPH_EMPTY ((void *)1)
5736 struct ftrace_graph_data {
5737 struct ftrace_hash *hash;
5738 struct ftrace_func_entry *entry;
5739 int idx; /* for hash table iteration */
5740 enum graph_filter_type type;
5741 struct ftrace_hash *new_hash;
5742 const struct seq_operations *seq_ops;
5743 struct trace_parser parser;
5747 __g_next(struct seq_file *m, loff_t *pos)
5749 struct ftrace_graph_data *fgd = m->private;
5750 struct ftrace_func_entry *entry = fgd->entry;
5751 struct hlist_head *head;
5752 int i, idx = fgd->idx;
5754 if (*pos >= fgd->hash->count)
5758 hlist_for_each_entry_continue(entry, hlist) {
5766 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5767 head = &fgd->hash->buckets[i];
5768 hlist_for_each_entry(entry, head, hlist) {
5778 g_next(struct seq_file *m, void *v, loff_t *pos)
5781 return __g_next(m, pos);
5784 static void *g_start(struct seq_file *m, loff_t *pos)
5786 struct ftrace_graph_data *fgd = m->private;
5788 mutex_lock(&graph_lock);
5790 if (fgd->type == GRAPH_FILTER_FUNCTION)
5791 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5792 lockdep_is_held(&graph_lock));
5794 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5795 lockdep_is_held(&graph_lock));
5797 /* Nothing, tell g_show to print all functions are enabled */
5798 if (ftrace_hash_empty(fgd->hash) && !*pos)
5799 return FTRACE_GRAPH_EMPTY;
5803 return __g_next(m, pos);
5806 static void g_stop(struct seq_file *m, void *p)
5808 mutex_unlock(&graph_lock);
5811 static int g_show(struct seq_file *m, void *v)
5813 struct ftrace_func_entry *entry = v;
5818 if (entry == FTRACE_GRAPH_EMPTY) {
5819 struct ftrace_graph_data *fgd = m->private;
5821 if (fgd->type == GRAPH_FILTER_FUNCTION)
5822 seq_puts(m, "#### all functions enabled ####\n");
5824 seq_puts(m, "#### no functions disabled ####\n");
5828 seq_printf(m, "%ps\n", (void *)entry->ip);
5833 static const struct seq_operations ftrace_graph_seq_ops = {
5841 __ftrace_graph_open(struct inode *inode, struct file *file,
5842 struct ftrace_graph_data *fgd)
5845 struct ftrace_hash *new_hash = NULL;
5847 ret = security_locked_down(LOCKDOWN_TRACEFS);
5851 if (file->f_mode & FMODE_WRITE) {
5852 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5854 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5857 if (file->f_flags & O_TRUNC)
5858 new_hash = alloc_ftrace_hash(size_bits);
5860 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5868 if (file->f_mode & FMODE_READ) {
5869 ret = seq_open(file, &ftrace_graph_seq_ops);
5871 struct seq_file *m = file->private_data;
5875 free_ftrace_hash(new_hash);
5879 file->private_data = fgd;
5882 if (ret < 0 && file->f_mode & FMODE_WRITE)
5883 trace_parser_put(&fgd->parser);
5885 fgd->new_hash = new_hash;
5888 * All uses of fgd->hash must be taken with the graph_lock
5889 * held. The graph_lock is going to be released, so force
5890 * fgd->hash to be reinitialized when it is taken again.
5898 ftrace_graph_open(struct inode *inode, struct file *file)
5900 struct ftrace_graph_data *fgd;
5903 if (unlikely(ftrace_disabled))
5906 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5910 mutex_lock(&graph_lock);
5912 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5913 lockdep_is_held(&graph_lock));
5914 fgd->type = GRAPH_FILTER_FUNCTION;
5915 fgd->seq_ops = &ftrace_graph_seq_ops;
5917 ret = __ftrace_graph_open(inode, file, fgd);
5921 mutex_unlock(&graph_lock);
5926 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5928 struct ftrace_graph_data *fgd;
5931 if (unlikely(ftrace_disabled))
5934 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5938 mutex_lock(&graph_lock);
5940 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5941 lockdep_is_held(&graph_lock));
5942 fgd->type = GRAPH_FILTER_NOTRACE;
5943 fgd->seq_ops = &ftrace_graph_seq_ops;
5945 ret = __ftrace_graph_open(inode, file, fgd);
5949 mutex_unlock(&graph_lock);
5954 ftrace_graph_release(struct inode *inode, struct file *file)
5956 struct ftrace_graph_data *fgd;
5957 struct ftrace_hash *old_hash, *new_hash;
5958 struct trace_parser *parser;
5961 if (file->f_mode & FMODE_READ) {
5962 struct seq_file *m = file->private_data;
5965 seq_release(inode, file);
5967 fgd = file->private_data;
5971 if (file->f_mode & FMODE_WRITE) {
5973 parser = &fgd->parser;
5975 if (trace_parser_loaded((parser))) {
5976 ret = ftrace_graph_set_hash(fgd->new_hash,
5980 trace_parser_put(parser);
5982 new_hash = __ftrace_hash_move(fgd->new_hash);
5988 mutex_lock(&graph_lock);
5990 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5991 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5992 lockdep_is_held(&graph_lock));
5993 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5995 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5996 lockdep_is_held(&graph_lock));
5997 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6000 mutex_unlock(&graph_lock);
6003 * We need to do a hard force of sched synchronization.
6004 * This is because we use preempt_disable() to do RCU, but
6005 * the function tracers can be called where RCU is not watching
6006 * (like before user_exit()). We can not rely on the RCU
6007 * infrastructure to do the synchronization, thus we must do it
6010 synchronize_rcu_tasks_rude();
6012 free_ftrace_hash(old_hash);
6016 free_ftrace_hash(fgd->new_hash);
6023 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6025 struct ftrace_glob func_g;
6026 struct dyn_ftrace *rec;
6027 struct ftrace_page *pg;
6028 struct ftrace_func_entry *entry;
6033 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6034 &func_g.search, ¬);
6036 func_g.len = strlen(func_g.search);
6038 mutex_lock(&ftrace_lock);
6040 if (unlikely(ftrace_disabled)) {
6041 mutex_unlock(&ftrace_lock);
6045 do_for_each_ftrace_rec(pg, rec) {
6047 if (rec->flags & FTRACE_FL_DISABLED)
6050 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6051 entry = ftrace_lookup_ip(hash, rec->ip);
6058 if (add_hash_entry(hash, rec->ip) < 0)
6062 free_hash_entry(hash, entry);
6067 } while_for_each_ftrace_rec();
6069 mutex_unlock(&ftrace_lock);
6078 ftrace_graph_write(struct file *file, const char __user *ubuf,
6079 size_t cnt, loff_t *ppos)
6081 ssize_t read, ret = 0;
6082 struct ftrace_graph_data *fgd = file->private_data;
6083 struct trace_parser *parser;
6088 /* Read mode uses seq functions */
6089 if (file->f_mode & FMODE_READ) {
6090 struct seq_file *m = file->private_data;
6094 parser = &fgd->parser;
6096 read = trace_get_user(parser, ubuf, cnt, ppos);
6098 if (read >= 0 && trace_parser_loaded(parser) &&
6099 !trace_parser_cont(parser)) {
6101 ret = ftrace_graph_set_hash(fgd->new_hash,
6103 trace_parser_clear(parser);
6112 static const struct file_operations ftrace_graph_fops = {
6113 .open = ftrace_graph_open,
6115 .write = ftrace_graph_write,
6116 .llseek = tracing_lseek,
6117 .release = ftrace_graph_release,
6120 static const struct file_operations ftrace_graph_notrace_fops = {
6121 .open = ftrace_graph_notrace_open,
6123 .write = ftrace_graph_write,
6124 .llseek = tracing_lseek,
6125 .release = ftrace_graph_release,
6127 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6129 void ftrace_create_filter_files(struct ftrace_ops *ops,
6130 struct dentry *parent)
6133 trace_create_file("set_ftrace_filter", 0644, parent,
6134 ops, &ftrace_filter_fops);
6136 trace_create_file("set_ftrace_notrace", 0644, parent,
6137 ops, &ftrace_notrace_fops);
6141 * The name "destroy_filter_files" is really a misnomer. Although
6142 * in the future, it may actually delete the files, but this is
6143 * really intended to make sure the ops passed in are disabled
6144 * and that when this function returns, the caller is free to
6147 * The "destroy" name is only to match the "create" name that this
6148 * should be paired with.
6150 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6152 mutex_lock(&ftrace_lock);
6153 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6154 ftrace_shutdown(ops, 0);
6155 ops->flags |= FTRACE_OPS_FL_DELETED;
6156 ftrace_free_filter(ops);
6157 mutex_unlock(&ftrace_lock);
6160 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6163 trace_create_file("available_filter_functions", 0444,
6164 d_tracer, NULL, &ftrace_avail_fops);
6166 trace_create_file("enabled_functions", 0444,
6167 d_tracer, NULL, &ftrace_enabled_fops);
6169 ftrace_create_filter_files(&global_ops, d_tracer);
6171 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6172 trace_create_file("set_graph_function", 0644, d_tracer,
6174 &ftrace_graph_fops);
6175 trace_create_file("set_graph_notrace", 0644, d_tracer,
6177 &ftrace_graph_notrace_fops);
6178 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6183 static int ftrace_cmp_ips(const void *a, const void *b)
6185 const unsigned long *ipa = a;
6186 const unsigned long *ipb = b;
6195 static int ftrace_process_locs(struct module *mod,
6196 unsigned long *start,
6199 struct ftrace_page *pg_unuse = NULL;
6200 struct ftrace_page *start_pg;
6201 struct ftrace_page *pg;
6202 struct dyn_ftrace *rec;
6203 unsigned long skipped = 0;
6204 unsigned long count;
6207 unsigned long flags = 0; /* Shut up gcc */
6210 count = end - start;
6215 sort(start, count, sizeof(*start),
6216 ftrace_cmp_ips, NULL);
6218 start_pg = ftrace_allocate_pages(count);
6222 mutex_lock(&ftrace_lock);
6225 * Core and each module needs their own pages, as
6226 * modules will free them when they are removed.
6227 * Force a new page to be allocated for modules.
6230 WARN_ON(ftrace_pages || ftrace_pages_start);
6231 /* First initialization */
6232 ftrace_pages = ftrace_pages_start = start_pg;
6237 if (WARN_ON(ftrace_pages->next)) {
6238 /* Hmm, we have free pages? */
6239 while (ftrace_pages->next)
6240 ftrace_pages = ftrace_pages->next;
6243 ftrace_pages->next = start_pg;
6249 unsigned long end_offset;
6250 addr = ftrace_call_adjust(*p++);
6252 * Some architecture linkers will pad between
6253 * the different mcount_loc sections of different
6254 * object files to satisfy alignments.
6255 * Skip any NULL pointers.
6262 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6263 if (end_offset > PAGE_SIZE << pg->order) {
6264 /* We should have allocated enough */
6265 if (WARN_ON(!pg->next))
6270 rec = &pg->records[pg->index++];
6275 pg_unuse = pg->next;
6279 /* Assign the last page to ftrace_pages */
6283 * We only need to disable interrupts on start up
6284 * because we are modifying code that an interrupt
6285 * may execute, and the modification is not atomic.
6286 * But for modules, nothing runs the code we modify
6287 * until we are finished with it, and there's no
6288 * reason to cause large interrupt latencies while we do it.
6291 local_irq_save(flags);
6292 ftrace_update_code(mod, start_pg);
6294 local_irq_restore(flags);
6297 mutex_unlock(&ftrace_lock);
6299 /* We should have used all pages unless we skipped some */
6302 ftrace_free_pages(pg_unuse);
6307 struct ftrace_mod_func {
6308 struct list_head list;
6314 struct ftrace_mod_map {
6315 struct rcu_head rcu;
6316 struct list_head list;
6318 unsigned long start_addr;
6319 unsigned long end_addr;
6320 struct list_head funcs;
6321 unsigned int num_funcs;
6324 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6325 unsigned long *value, char *type,
6326 char *name, char *module_name,
6329 struct ftrace_ops *op;
6331 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6332 if (!op->trampoline || symnum--)
6334 *value = op->trampoline;
6336 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6337 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6345 #ifdef CONFIG_MODULES
6347 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6349 static LIST_HEAD(ftrace_mod_maps);
6351 static int referenced_filters(struct dyn_ftrace *rec)
6353 struct ftrace_ops *ops;
6356 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6357 if (ops_references_rec(ops, rec)) {
6358 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6360 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6363 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6364 rec->flags |= FTRACE_FL_REGS;
6365 if (cnt == 1 && ops->trampoline)
6366 rec->flags |= FTRACE_FL_TRAMP;
6368 rec->flags &= ~FTRACE_FL_TRAMP;
6376 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6378 struct ftrace_func_entry *entry;
6379 struct dyn_ftrace *rec;
6382 if (ftrace_hash_empty(hash))
6385 for (i = 0; i < pg->index; i++) {
6386 rec = &pg->records[i];
6387 entry = __ftrace_lookup_ip(hash, rec->ip);
6389 * Do not allow this rec to match again.
6390 * Yeah, it may waste some memory, but will be removed
6391 * if/when the hash is modified again.
6398 /* Clear any records from hashs */
6399 static void clear_mod_from_hashes(struct ftrace_page *pg)
6401 struct trace_array *tr;
6403 mutex_lock(&trace_types_lock);
6404 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6405 if (!tr->ops || !tr->ops->func_hash)
6407 mutex_lock(&tr->ops->func_hash->regex_lock);
6408 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6409 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6410 mutex_unlock(&tr->ops->func_hash->regex_lock);
6412 mutex_unlock(&trace_types_lock);
6415 static void ftrace_free_mod_map(struct rcu_head *rcu)
6417 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6418 struct ftrace_mod_func *mod_func;
6419 struct ftrace_mod_func *n;
6421 /* All the contents of mod_map are now not visible to readers */
6422 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6423 kfree(mod_func->name);
6424 list_del(&mod_func->list);
6431 void ftrace_release_mod(struct module *mod)
6433 struct ftrace_mod_map *mod_map;
6434 struct ftrace_mod_map *n;
6435 struct dyn_ftrace *rec;
6436 struct ftrace_page **last_pg;
6437 struct ftrace_page *tmp_page = NULL;
6438 struct ftrace_page *pg;
6440 mutex_lock(&ftrace_lock);
6442 if (ftrace_disabled)
6445 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6446 if (mod_map->mod == mod) {
6447 list_del_rcu(&mod_map->list);
6448 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6454 * Each module has its own ftrace_pages, remove
6455 * them from the list.
6457 last_pg = &ftrace_pages_start;
6458 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6459 rec = &pg->records[0];
6460 if (within_module_core(rec->ip, mod) ||
6461 within_module_init(rec->ip, mod)) {
6463 * As core pages are first, the first
6464 * page should never be a module page.
6466 if (WARN_ON(pg == ftrace_pages_start))
6469 /* Check if we are deleting the last page */
6470 if (pg == ftrace_pages)
6471 ftrace_pages = next_to_ftrace_page(last_pg);
6473 ftrace_update_tot_cnt -= pg->index;
6474 *last_pg = pg->next;
6476 pg->next = tmp_page;
6479 last_pg = &pg->next;
6482 mutex_unlock(&ftrace_lock);
6484 for (pg = tmp_page; pg; pg = tmp_page) {
6486 /* Needs to be called outside of ftrace_lock */
6487 clear_mod_from_hashes(pg);
6490 free_pages((unsigned long)pg->records, pg->order);
6491 ftrace_number_of_pages -= 1 << pg->order;
6493 tmp_page = pg->next;
6495 ftrace_number_of_groups--;
6499 void ftrace_module_enable(struct module *mod)
6501 struct dyn_ftrace *rec;
6502 struct ftrace_page *pg;
6504 mutex_lock(&ftrace_lock);
6506 if (ftrace_disabled)
6510 * If the tracing is enabled, go ahead and enable the record.
6512 * The reason not to enable the record immediately is the
6513 * inherent check of ftrace_make_nop/ftrace_make_call for
6514 * correct previous instructions. Making first the NOP
6515 * conversion puts the module to the correct state, thus
6516 * passing the ftrace_make_call check.
6518 * We also delay this to after the module code already set the
6519 * text to read-only, as we now need to set it back to read-write
6520 * so that we can modify the text.
6522 if (ftrace_start_up)
6523 ftrace_arch_code_modify_prepare();
6525 do_for_each_ftrace_rec(pg, rec) {
6528 * do_for_each_ftrace_rec() is a double loop.
6529 * module text shares the pg. If a record is
6530 * not part of this module, then skip this pg,
6531 * which the "break" will do.
6533 if (!within_module_core(rec->ip, mod) &&
6534 !within_module_init(rec->ip, mod))
6540 * When adding a module, we need to check if tracers are
6541 * currently enabled and if they are, and can trace this record,
6542 * we need to enable the module functions as well as update the
6543 * reference counts for those function records.
6545 if (ftrace_start_up)
6546 cnt += referenced_filters(rec);
6548 rec->flags &= ~FTRACE_FL_DISABLED;
6551 if (ftrace_start_up && cnt) {
6552 int failed = __ftrace_replace_code(rec, 1);
6554 ftrace_bug(failed, rec);
6559 } while_for_each_ftrace_rec();
6562 if (ftrace_start_up)
6563 ftrace_arch_code_modify_post_process();
6566 mutex_unlock(&ftrace_lock);
6568 process_cached_mods(mod->name);
6571 void ftrace_module_init(struct module *mod)
6573 if (ftrace_disabled || !mod->num_ftrace_callsites)
6576 ftrace_process_locs(mod, mod->ftrace_callsites,
6577 mod->ftrace_callsites + mod->num_ftrace_callsites);
6580 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6581 struct dyn_ftrace *rec)
6583 struct ftrace_mod_func *mod_func;
6584 unsigned long symsize;
6585 unsigned long offset;
6586 char str[KSYM_SYMBOL_LEN];
6590 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6594 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6598 mod_func->name = kstrdup(str, GFP_KERNEL);
6599 if (!mod_func->name) {
6604 mod_func->ip = rec->ip - offset;
6605 mod_func->size = symsize;
6607 mod_map->num_funcs++;
6609 list_add_rcu(&mod_func->list, &mod_map->funcs);
6612 static struct ftrace_mod_map *
6613 allocate_ftrace_mod_map(struct module *mod,
6614 unsigned long start, unsigned long end)
6616 struct ftrace_mod_map *mod_map;
6618 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6623 mod_map->start_addr = start;
6624 mod_map->end_addr = end;
6625 mod_map->num_funcs = 0;
6627 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6629 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6635 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6636 unsigned long addr, unsigned long *size,
6637 unsigned long *off, char *sym)
6639 struct ftrace_mod_func *found_func = NULL;
6640 struct ftrace_mod_func *mod_func;
6642 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6643 if (addr >= mod_func->ip &&
6644 addr < mod_func->ip + mod_func->size) {
6645 found_func = mod_func;
6652 *size = found_func->size;
6654 *off = addr - found_func->ip;
6656 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6658 return found_func->name;
6665 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6666 unsigned long *off, char **modname, char *sym)
6668 struct ftrace_mod_map *mod_map;
6669 const char *ret = NULL;
6671 /* mod_map is freed via call_rcu() */
6673 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6674 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6677 *modname = mod_map->mod->name;
6686 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6687 char *type, char *name,
6688 char *module_name, int *exported)
6690 struct ftrace_mod_map *mod_map;
6691 struct ftrace_mod_func *mod_func;
6695 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6697 if (symnum >= mod_map->num_funcs) {
6698 symnum -= mod_map->num_funcs;
6702 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6708 *value = mod_func->ip;
6710 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6711 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6719 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6720 module_name, exported);
6726 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6727 struct dyn_ftrace *rec) { }
6728 static inline struct ftrace_mod_map *
6729 allocate_ftrace_mod_map(struct module *mod,
6730 unsigned long start, unsigned long end)
6734 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6735 char *type, char *name, char *module_name,
6741 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6742 module_name, exported);
6746 #endif /* CONFIG_MODULES */
6748 struct ftrace_init_func {
6749 struct list_head list;
6753 /* Clear any init ips from hashes */
6755 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6757 struct ftrace_func_entry *entry;
6759 entry = ftrace_lookup_ip(hash, func->ip);
6761 * Do not allow this rec to match again.
6762 * Yeah, it may waste some memory, but will be removed
6763 * if/when the hash is modified again.
6770 clear_func_from_hashes(struct ftrace_init_func *func)
6772 struct trace_array *tr;
6774 mutex_lock(&trace_types_lock);
6775 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6776 if (!tr->ops || !tr->ops->func_hash)
6778 mutex_lock(&tr->ops->func_hash->regex_lock);
6779 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6780 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6781 mutex_unlock(&tr->ops->func_hash->regex_lock);
6783 mutex_unlock(&trace_types_lock);
6786 static void add_to_clear_hash_list(struct list_head *clear_list,
6787 struct dyn_ftrace *rec)
6789 struct ftrace_init_func *func;
6791 func = kmalloc(sizeof(*func), GFP_KERNEL);
6793 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6798 list_add(&func->list, clear_list);
6801 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6803 unsigned long start = (unsigned long)(start_ptr);
6804 unsigned long end = (unsigned long)(end_ptr);
6805 struct ftrace_page **last_pg = &ftrace_pages_start;
6806 struct ftrace_page *pg;
6807 struct dyn_ftrace *rec;
6808 struct dyn_ftrace key;
6809 struct ftrace_mod_map *mod_map = NULL;
6810 struct ftrace_init_func *func, *func_next;
6811 struct list_head clear_hash;
6813 INIT_LIST_HEAD(&clear_hash);
6816 key.flags = end; /* overload flags, as it is unsigned long */
6818 mutex_lock(&ftrace_lock);
6821 * If we are freeing module init memory, then check if
6822 * any tracer is active. If so, we need to save a mapping of
6823 * the module functions being freed with the address.
6825 if (mod && ftrace_ops_list != &ftrace_list_end)
6826 mod_map = allocate_ftrace_mod_map(mod, start, end);
6828 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6829 if (end < pg->records[0].ip ||
6830 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6833 rec = bsearch(&key, pg->records, pg->index,
6834 sizeof(struct dyn_ftrace),
6839 /* rec will be cleared from hashes after ftrace_lock unlock */
6840 add_to_clear_hash_list(&clear_hash, rec);
6843 save_ftrace_mod_rec(mod_map, rec);
6846 ftrace_update_tot_cnt--;
6848 *last_pg = pg->next;
6850 free_pages((unsigned long)pg->records, pg->order);
6851 ftrace_number_of_pages -= 1 << pg->order;
6853 ftrace_number_of_groups--;
6855 pg = container_of(last_pg, struct ftrace_page, next);
6860 memmove(rec, rec + 1,
6861 (pg->index - (rec - pg->records)) * sizeof(*rec));
6862 /* More than one function may be in this block */
6865 mutex_unlock(&ftrace_lock);
6867 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6868 clear_func_from_hashes(func);
6873 void __init ftrace_free_init_mem(void)
6875 void *start = (void *)(&__init_begin);
6876 void *end = (void *)(&__init_end);
6878 ftrace_free_mem(NULL, start, end);
6881 void __init ftrace_init(void)
6883 extern unsigned long __start_mcount_loc[];
6884 extern unsigned long __stop_mcount_loc[];
6885 unsigned long count, flags;
6888 local_irq_save(flags);
6889 ret = ftrace_dyn_arch_init();
6890 local_irq_restore(flags);
6894 count = __stop_mcount_loc - __start_mcount_loc;
6896 pr_info("ftrace: No functions to be traced?\n");
6900 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6901 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
6903 last_ftrace_enabled = ftrace_enabled = 1;
6905 ret = ftrace_process_locs(NULL,
6909 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6910 ftrace_number_of_pages, ftrace_number_of_groups);
6912 set_ftrace_early_filters();
6916 ftrace_disabled = 1;
6919 /* Do nothing if arch does not support this */
6920 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6924 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6926 unsigned long trampoline = ops->trampoline;
6928 arch_ftrace_update_trampoline(ops);
6929 if (ops->trampoline && ops->trampoline != trampoline &&
6930 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6931 /* Add to kallsyms before the perf events */
6932 ftrace_add_trampoline_to_kallsyms(ops);
6933 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6934 ops->trampoline, ops->trampoline_size, false,
6935 FTRACE_TRAMPOLINE_SYM);
6937 * Record the perf text poke event after the ksymbol register
6940 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6941 (void *)ops->trampoline,
6942 ops->trampoline_size);
6946 void ftrace_init_trace_array(struct trace_array *tr)
6948 INIT_LIST_HEAD(&tr->func_probes);
6949 INIT_LIST_HEAD(&tr->mod_trace);
6950 INIT_LIST_HEAD(&tr->mod_notrace);
6954 struct ftrace_ops global_ops = {
6955 .func = ftrace_stub,
6956 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6957 FTRACE_OPS_FL_INITIALIZED |
6961 static int __init ftrace_nodyn_init(void)
6966 core_initcall(ftrace_nodyn_init);
6968 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6969 static inline void ftrace_startup_enable(int command) { }
6970 static inline void ftrace_startup_all(int command) { }
6972 # define ftrace_startup_sysctl() do { } while (0)
6973 # define ftrace_shutdown_sysctl() do { } while (0)
6975 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6979 #endif /* CONFIG_DYNAMIC_FTRACE */
6981 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6983 tr->ops = &global_ops;
6984 tr->ops->private = tr;
6985 ftrace_init_trace_array(tr);
6988 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6990 /* If we filter on pids, update to use the pid function */
6991 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6992 if (WARN_ON(tr->ops->func != ftrace_stub))
6993 printk("ftrace ops had %pS for function\n",
6996 tr->ops->func = func;
6997 tr->ops->private = tr;
7000 void ftrace_reset_array_ops(struct trace_array *tr)
7002 tr->ops->func = ftrace_stub;
7005 static nokprobe_inline void
7006 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7007 struct ftrace_ops *ignored, struct pt_regs *regs)
7009 struct ftrace_ops *op;
7012 bit = trace_test_and_set_recursion(TRACE_LIST_START);
7017 * Some of the ops may be dynamically allocated,
7018 * they must be freed after a synchronize_rcu().
7020 preempt_disable_notrace();
7022 do_for_each_ftrace_op(op, ftrace_ops_list) {
7023 /* Stub functions don't need to be called nor tested */
7024 if (op->flags & FTRACE_OPS_FL_STUB)
7027 * Check the following for each ops before calling their func:
7028 * if RCU flag is set, then rcu_is_watching() must be true
7029 * if PER_CPU is set, then ftrace_function_local_disable()
7031 * Otherwise test if the ip matches the ops filter
7033 * If any of the above fails then the op->func() is not executed.
7035 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7036 ftrace_ops_test(op, ip, regs)) {
7037 if (FTRACE_WARN_ON(!op->func)) {
7038 pr_warn("op=%p %pS\n", op, op);
7041 op->func(ip, parent_ip, op, regs);
7043 } while_for_each_ftrace_op(op);
7045 preempt_enable_notrace();
7046 trace_clear_recursion(bit);
7050 * Some archs only support passing ip and parent_ip. Even though
7051 * the list function ignores the op parameter, we do not want any
7052 * C side effects, where a function is called without the caller
7053 * sending a third parameter.
7054 * Archs are to support both the regs and ftrace_ops at the same time.
7055 * If they support ftrace_ops, it is assumed they support regs.
7056 * If call backs want to use regs, they must either check for regs
7057 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7058 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7059 * An architecture can pass partial regs with ftrace_ops and still
7060 * set the ARCH_SUPPORTS_FTRACE_OPS.
7062 #if ARCH_SUPPORTS_FTRACE_OPS
7063 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7064 struct ftrace_ops *op, struct pt_regs *regs)
7066 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
7068 NOKPROBE_SYMBOL(ftrace_ops_list_func);
7070 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
7072 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7074 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
7078 * If there's only one function registered but it does not support
7079 * recursion, needs RCU protection and/or requires per cpu handling, then
7080 * this function will be called by the mcount trampoline.
7082 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7083 struct ftrace_ops *op, struct pt_regs *regs)
7087 bit = trace_test_and_set_recursion(TRACE_LIST_START);
7091 preempt_disable_notrace();
7093 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7094 op->func(ip, parent_ip, op, regs);
7096 preempt_enable_notrace();
7097 trace_clear_recursion(bit);
7099 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7102 * ftrace_ops_get_func - get the function a trampoline should call
7103 * @ops: the ops to get the function for
7105 * Normally the mcount trampoline will call the ops->func, but there
7106 * are times that it should not. For example, if the ops does not
7107 * have its own recursion protection, then it should call the
7108 * ftrace_ops_assist_func() instead.
7110 * Returns the function that the trampoline should call for @ops.
7112 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7115 * If the function does not handle recursion, needs to be RCU safe,
7116 * or does per cpu logic, then we need to call the assist handler.
7118 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
7119 ops->flags & FTRACE_OPS_FL_RCU)
7120 return ftrace_ops_assist_func;
7126 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7127 struct task_struct *prev, struct task_struct *next)
7129 struct trace_array *tr = data;
7130 struct trace_pid_list *pid_list;
7131 struct trace_pid_list *no_pid_list;
7133 pid_list = rcu_dereference_sched(tr->function_pids);
7134 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7136 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7137 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7140 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7145 ftrace_pid_follow_sched_process_fork(void *data,
7146 struct task_struct *self,
7147 struct task_struct *task)
7149 struct trace_pid_list *pid_list;
7150 struct trace_array *tr = data;
7152 pid_list = rcu_dereference_sched(tr->function_pids);
7153 trace_filter_add_remove_task(pid_list, self, task);
7155 pid_list = rcu_dereference_sched(tr->function_no_pids);
7156 trace_filter_add_remove_task(pid_list, self, task);
7160 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7162 struct trace_pid_list *pid_list;
7163 struct trace_array *tr = data;
7165 pid_list = rcu_dereference_sched(tr->function_pids);
7166 trace_filter_add_remove_task(pid_list, NULL, task);
7168 pid_list = rcu_dereference_sched(tr->function_no_pids);
7169 trace_filter_add_remove_task(pid_list, NULL, task);
7172 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7175 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7177 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7180 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7182 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7187 static void clear_ftrace_pids(struct trace_array *tr, int type)
7189 struct trace_pid_list *pid_list;
7190 struct trace_pid_list *no_pid_list;
7193 pid_list = rcu_dereference_protected(tr->function_pids,
7194 lockdep_is_held(&ftrace_lock));
7195 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7196 lockdep_is_held(&ftrace_lock));
7198 /* Make sure there's something to do */
7199 if (!pid_type_enabled(type, pid_list, no_pid_list))
7202 /* See if the pids still need to be checked after this */
7203 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7204 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7205 for_each_possible_cpu(cpu)
7206 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7209 if (type & TRACE_PIDS)
7210 rcu_assign_pointer(tr->function_pids, NULL);
7212 if (type & TRACE_NO_PIDS)
7213 rcu_assign_pointer(tr->function_no_pids, NULL);
7215 /* Wait till all users are no longer using pid filtering */
7218 if ((type & TRACE_PIDS) && pid_list)
7219 trace_free_pid_list(pid_list);
7221 if ((type & TRACE_NO_PIDS) && no_pid_list)
7222 trace_free_pid_list(no_pid_list);
7225 void ftrace_clear_pids(struct trace_array *tr)
7227 mutex_lock(&ftrace_lock);
7229 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7231 mutex_unlock(&ftrace_lock);
7234 static void ftrace_pid_reset(struct trace_array *tr, int type)
7236 mutex_lock(&ftrace_lock);
7237 clear_ftrace_pids(tr, type);
7239 ftrace_update_pid_func();
7240 ftrace_startup_all(0);
7242 mutex_unlock(&ftrace_lock);
7245 /* Greater than any max PID */
7246 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7248 static void *fpid_start(struct seq_file *m, loff_t *pos)
7251 struct trace_pid_list *pid_list;
7252 struct trace_array *tr = m->private;
7254 mutex_lock(&ftrace_lock);
7255 rcu_read_lock_sched();
7257 pid_list = rcu_dereference_sched(tr->function_pids);
7260 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7262 return trace_pid_start(pid_list, pos);
7265 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7267 struct trace_array *tr = m->private;
7268 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7270 if (v == FTRACE_NO_PIDS) {
7274 return trace_pid_next(pid_list, v, pos);
7277 static void fpid_stop(struct seq_file *m, void *p)
7280 rcu_read_unlock_sched();
7281 mutex_unlock(&ftrace_lock);
7284 static int fpid_show(struct seq_file *m, void *v)
7286 if (v == FTRACE_NO_PIDS) {
7287 seq_puts(m, "no pid\n");
7291 return trace_pid_show(m, v);
7294 static const struct seq_operations ftrace_pid_sops = {
7295 .start = fpid_start,
7301 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7304 struct trace_pid_list *pid_list;
7305 struct trace_array *tr = m->private;
7307 mutex_lock(&ftrace_lock);
7308 rcu_read_lock_sched();
7310 pid_list = rcu_dereference_sched(tr->function_no_pids);
7313 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7315 return trace_pid_start(pid_list, pos);
7318 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7320 struct trace_array *tr = m->private;
7321 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7323 if (v == FTRACE_NO_PIDS) {
7327 return trace_pid_next(pid_list, v, pos);
7330 static const struct seq_operations ftrace_no_pid_sops = {
7331 .start = fnpid_start,
7337 static int pid_open(struct inode *inode, struct file *file, int type)
7339 const struct seq_operations *seq_ops;
7340 struct trace_array *tr = inode->i_private;
7344 ret = tracing_check_open_get_tr(tr);
7348 if ((file->f_mode & FMODE_WRITE) &&
7349 (file->f_flags & O_TRUNC))
7350 ftrace_pid_reset(tr, type);
7354 seq_ops = &ftrace_pid_sops;
7357 seq_ops = &ftrace_no_pid_sops;
7360 trace_array_put(tr);
7365 ret = seq_open(file, seq_ops);
7367 trace_array_put(tr);
7369 m = file->private_data;
7370 /* copy tr over to seq ops */
7378 ftrace_pid_open(struct inode *inode, struct file *file)
7380 return pid_open(inode, file, TRACE_PIDS);
7384 ftrace_no_pid_open(struct inode *inode, struct file *file)
7386 return pid_open(inode, file, TRACE_NO_PIDS);
7389 static void ignore_task_cpu(void *data)
7391 struct trace_array *tr = data;
7392 struct trace_pid_list *pid_list;
7393 struct trace_pid_list *no_pid_list;
7396 * This function is called by on_each_cpu() while the
7397 * event_mutex is held.
7399 pid_list = rcu_dereference_protected(tr->function_pids,
7400 mutex_is_locked(&ftrace_lock));
7401 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7402 mutex_is_locked(&ftrace_lock));
7404 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7405 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7408 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7413 pid_write(struct file *filp, const char __user *ubuf,
7414 size_t cnt, loff_t *ppos, int type)
7416 struct seq_file *m = filp->private_data;
7417 struct trace_array *tr = m->private;
7418 struct trace_pid_list *filtered_pids;
7419 struct trace_pid_list *other_pids;
7420 struct trace_pid_list *pid_list;
7426 mutex_lock(&ftrace_lock);
7430 filtered_pids = rcu_dereference_protected(tr->function_pids,
7431 lockdep_is_held(&ftrace_lock));
7432 other_pids = rcu_dereference_protected(tr->function_no_pids,
7433 lockdep_is_held(&ftrace_lock));
7436 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7437 lockdep_is_held(&ftrace_lock));
7438 other_pids = rcu_dereference_protected(tr->function_pids,
7439 lockdep_is_held(&ftrace_lock));
7447 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7453 rcu_assign_pointer(tr->function_pids, pid_list);
7456 rcu_assign_pointer(tr->function_no_pids, pid_list);
7461 if (filtered_pids) {
7463 trace_free_pid_list(filtered_pids);
7464 } else if (pid_list && !other_pids) {
7465 /* Register a probe to set whether to ignore the tracing of a task */
7466 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7470 * Ignoring of pids is done at task switch. But we have to
7471 * check for those tasks that are currently running.
7472 * Always do this in case a pid was appended or removed.
7474 on_each_cpu(ignore_task_cpu, tr, 1);
7476 ftrace_update_pid_func();
7477 ftrace_startup_all(0);
7479 mutex_unlock(&ftrace_lock);
7488 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7489 size_t cnt, loff_t *ppos)
7491 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7495 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7496 size_t cnt, loff_t *ppos)
7498 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7502 ftrace_pid_release(struct inode *inode, struct file *file)
7504 struct trace_array *tr = inode->i_private;
7506 trace_array_put(tr);
7508 return seq_release(inode, file);
7511 static const struct file_operations ftrace_pid_fops = {
7512 .open = ftrace_pid_open,
7513 .write = ftrace_pid_write,
7515 .llseek = tracing_lseek,
7516 .release = ftrace_pid_release,
7519 static const struct file_operations ftrace_no_pid_fops = {
7520 .open = ftrace_no_pid_open,
7521 .write = ftrace_no_pid_write,
7523 .llseek = tracing_lseek,
7524 .release = ftrace_pid_release,
7527 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7529 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7530 tr, &ftrace_pid_fops);
7531 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7532 tr, &ftrace_no_pid_fops);
7535 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7536 struct dentry *d_tracer)
7538 /* Only the top level directory has the dyn_tracefs and profile */
7539 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7541 ftrace_init_dyn_tracefs(d_tracer);
7542 ftrace_profile_tracefs(d_tracer);
7546 * ftrace_kill - kill ftrace
7548 * This function should be used by panic code. It stops ftrace
7549 * but in a not so nice way. If you need to simply kill ftrace
7550 * from a non-atomic section, use ftrace_kill.
7552 void ftrace_kill(void)
7554 ftrace_disabled = 1;
7556 ftrace_trace_function = ftrace_stub;
7560 * Test if ftrace is dead or not.
7562 int ftrace_is_dead(void)
7564 return ftrace_disabled;
7568 * register_ftrace_function - register a function for profiling
7569 * @ops - ops structure that holds the function for profiling.
7571 * Register a function to be called by all functions in the
7574 * Note: @ops->func and all the functions it calls must be labeled
7575 * with "notrace", otherwise it will go into a
7578 int register_ftrace_function(struct ftrace_ops *ops)
7582 ftrace_ops_init(ops);
7584 mutex_lock(&ftrace_lock);
7586 ret = ftrace_startup(ops, 0);
7588 mutex_unlock(&ftrace_lock);
7592 EXPORT_SYMBOL_GPL(register_ftrace_function);
7595 * unregister_ftrace_function - unregister a function for profiling.
7596 * @ops - ops structure that holds the function to unregister
7598 * Unregister a function that was added to be called by ftrace profiling.
7600 int unregister_ftrace_function(struct ftrace_ops *ops)
7604 mutex_lock(&ftrace_lock);
7605 ret = ftrace_shutdown(ops, 0);
7606 mutex_unlock(&ftrace_lock);
7610 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7612 static bool is_permanent_ops_registered(void)
7614 struct ftrace_ops *op;
7616 do_for_each_ftrace_op(op, ftrace_ops_list) {
7617 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7619 } while_for_each_ftrace_op(op);
7625 ftrace_enable_sysctl(struct ctl_table *table, int write,
7626 void *buffer, size_t *lenp, loff_t *ppos)
7630 mutex_lock(&ftrace_lock);
7632 if (unlikely(ftrace_disabled))
7635 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7637 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7640 if (ftrace_enabled) {
7642 /* we are starting ftrace again */
7643 if (rcu_dereference_protected(ftrace_ops_list,
7644 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7645 update_ftrace_function();
7647 ftrace_startup_sysctl();
7650 if (is_permanent_ops_registered()) {
7651 ftrace_enabled = true;
7656 /* stopping ftrace calls (just send to ftrace_stub) */
7657 ftrace_trace_function = ftrace_stub;
7659 ftrace_shutdown_sysctl();
7662 last_ftrace_enabled = !!ftrace_enabled;
7664 mutex_unlock(&ftrace_lock);