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_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 ftrace_regs *fregs);
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 ftrace_regs *fregs)
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, fregs);
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 ftrace_regs *fregs)
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_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_INITIALIZED |
1048 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1050 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1052 struct ftrace_ops *op = NULL;
1055 * Some of the ops may be dynamically allocated,
1056 * they are freed after a synchronize_rcu().
1058 preempt_disable_notrace();
1060 do_for_each_ftrace_op(op, ftrace_ops_list) {
1062 * This is to check for dynamically allocated trampolines.
1063 * Trampolines that are in kernel text will have
1064 * core_kernel_text() return true.
1066 if (op->trampoline && op->trampoline_size)
1067 if (addr >= op->trampoline &&
1068 addr < op->trampoline + op->trampoline_size) {
1069 preempt_enable_notrace();
1072 } while_for_each_ftrace_op(op);
1073 preempt_enable_notrace();
1079 * This is used by __kernel_text_address() to return true if the
1080 * address is on a dynamically allocated trampoline that would
1081 * not return true for either core_kernel_text() or
1082 * is_module_text_address().
1084 bool is_ftrace_trampoline(unsigned long addr)
1086 return ftrace_ops_trampoline(addr) != NULL;
1089 struct ftrace_page {
1090 struct ftrace_page *next;
1091 struct dyn_ftrace *records;
1096 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1097 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1099 static struct ftrace_page *ftrace_pages_start;
1100 static struct ftrace_page *ftrace_pages;
1102 static __always_inline unsigned long
1103 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1105 if (hash->size_bits > 0)
1106 return hash_long(ip, hash->size_bits);
1111 /* Only use this function if ftrace_hash_empty() has already been tested */
1112 static __always_inline struct ftrace_func_entry *
1113 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1116 struct ftrace_func_entry *entry;
1117 struct hlist_head *hhd;
1119 key = ftrace_hash_key(hash, ip);
1120 hhd = &hash->buckets[key];
1122 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1123 if (entry->ip == ip)
1130 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1131 * @hash: The hash to look at
1132 * @ip: The instruction pointer to test
1134 * Search a given @hash to see if a given instruction pointer (@ip)
1137 * Returns the entry that holds the @ip if found. NULL otherwise.
1139 struct ftrace_func_entry *
1140 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1142 if (ftrace_hash_empty(hash))
1145 return __ftrace_lookup_ip(hash, ip);
1148 static void __add_hash_entry(struct ftrace_hash *hash,
1149 struct ftrace_func_entry *entry)
1151 struct hlist_head *hhd;
1154 key = ftrace_hash_key(hash, entry->ip);
1155 hhd = &hash->buckets[key];
1156 hlist_add_head(&entry->hlist, hhd);
1160 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1162 struct ftrace_func_entry *entry;
1164 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1169 __add_hash_entry(hash, entry);
1175 free_hash_entry(struct ftrace_hash *hash,
1176 struct ftrace_func_entry *entry)
1178 hlist_del(&entry->hlist);
1184 remove_hash_entry(struct ftrace_hash *hash,
1185 struct ftrace_func_entry *entry)
1187 hlist_del_rcu(&entry->hlist);
1191 static void ftrace_hash_clear(struct ftrace_hash *hash)
1193 struct hlist_head *hhd;
1194 struct hlist_node *tn;
1195 struct ftrace_func_entry *entry;
1196 int size = 1 << hash->size_bits;
1202 for (i = 0; i < size; i++) {
1203 hhd = &hash->buckets[i];
1204 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1205 free_hash_entry(hash, entry);
1207 FTRACE_WARN_ON(hash->count);
1210 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1212 list_del(&ftrace_mod->list);
1213 kfree(ftrace_mod->module);
1214 kfree(ftrace_mod->func);
1218 static void clear_ftrace_mod_list(struct list_head *head)
1220 struct ftrace_mod_load *p, *n;
1222 /* stack tracer isn't supported yet */
1226 mutex_lock(&ftrace_lock);
1227 list_for_each_entry_safe(p, n, head, list)
1229 mutex_unlock(&ftrace_lock);
1232 static void free_ftrace_hash(struct ftrace_hash *hash)
1234 if (!hash || hash == EMPTY_HASH)
1236 ftrace_hash_clear(hash);
1237 kfree(hash->buckets);
1241 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1243 struct ftrace_hash *hash;
1245 hash = container_of(rcu, struct ftrace_hash, rcu);
1246 free_ftrace_hash(hash);
1249 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1251 if (!hash || hash == EMPTY_HASH)
1253 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1256 void ftrace_free_filter(struct ftrace_ops *ops)
1258 ftrace_ops_init(ops);
1259 free_ftrace_hash(ops->func_hash->filter_hash);
1260 free_ftrace_hash(ops->func_hash->notrace_hash);
1263 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1265 struct ftrace_hash *hash;
1268 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1272 size = 1 << size_bits;
1273 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1275 if (!hash->buckets) {
1280 hash->size_bits = size_bits;
1286 static int ftrace_add_mod(struct trace_array *tr,
1287 const char *func, const char *module,
1290 struct ftrace_mod_load *ftrace_mod;
1291 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1293 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1297 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1298 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1299 ftrace_mod->enable = enable;
1301 if (!ftrace_mod->func || !ftrace_mod->module)
1304 list_add(&ftrace_mod->list, mod_head);
1309 free_ftrace_mod(ftrace_mod);
1314 static struct ftrace_hash *
1315 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1317 struct ftrace_func_entry *entry;
1318 struct ftrace_hash *new_hash;
1323 new_hash = alloc_ftrace_hash(size_bits);
1328 new_hash->flags = hash->flags;
1331 if (ftrace_hash_empty(hash))
1334 size = 1 << hash->size_bits;
1335 for (i = 0; i < size; i++) {
1336 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1337 ret = add_hash_entry(new_hash, entry->ip);
1343 FTRACE_WARN_ON(new_hash->count != hash->count);
1348 free_ftrace_hash(new_hash);
1353 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1355 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1357 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1358 struct ftrace_hash *new_hash);
1360 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1362 struct ftrace_func_entry *entry;
1363 struct ftrace_hash *new_hash;
1364 struct hlist_head *hhd;
1365 struct hlist_node *tn;
1370 * Use around half the size (max bit of it), but
1371 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1373 bits = fls(size / 2);
1375 /* Don't allocate too much */
1376 if (bits > FTRACE_HASH_MAX_BITS)
1377 bits = FTRACE_HASH_MAX_BITS;
1379 new_hash = alloc_ftrace_hash(bits);
1383 new_hash->flags = src->flags;
1385 size = 1 << src->size_bits;
1386 for (i = 0; i < size; i++) {
1387 hhd = &src->buckets[i];
1388 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1389 remove_hash_entry(src, entry);
1390 __add_hash_entry(new_hash, entry);
1396 static struct ftrace_hash *
1397 __ftrace_hash_move(struct ftrace_hash *src)
1399 int size = src->count;
1402 * If the new source is empty, just return the empty_hash.
1404 if (ftrace_hash_empty(src))
1407 return dup_hash(src, size);
1411 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1412 struct ftrace_hash **dst, struct ftrace_hash *src)
1414 struct ftrace_hash *new_hash;
1417 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1418 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1421 new_hash = __ftrace_hash_move(src);
1425 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1427 /* IPMODIFY should be updated only when filter_hash updating */
1428 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1430 free_ftrace_hash(new_hash);
1436 * Remove the current set, update the hash and add
1439 ftrace_hash_rec_disable_modify(ops, enable);
1441 rcu_assign_pointer(*dst, new_hash);
1443 ftrace_hash_rec_enable_modify(ops, enable);
1448 static bool hash_contains_ip(unsigned long ip,
1449 struct ftrace_ops_hash *hash)
1452 * The function record is a match if it exists in the filter
1453 * hash and not in the notrace hash. Note, an empty hash is
1454 * considered a match for the filter hash, but an empty
1455 * notrace hash is considered not in the notrace hash.
1457 return (ftrace_hash_empty(hash->filter_hash) ||
1458 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1459 (ftrace_hash_empty(hash->notrace_hash) ||
1460 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1464 * Test the hashes for this ops to see if we want to call
1465 * the ops->func or not.
1467 * It's a match if the ip is in the ops->filter_hash or
1468 * the filter_hash does not exist or is empty,
1470 * the ip is not in the ops->notrace_hash.
1472 * This needs to be called with preemption disabled as
1473 * the hashes are freed with call_rcu().
1476 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1478 struct ftrace_ops_hash hash;
1481 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1483 * There's a small race when adding ops that the ftrace handler
1484 * that wants regs, may be called without them. We can not
1485 * allow that handler to be called if regs is NULL.
1487 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1491 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1492 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1494 if (hash_contains_ip(ip, &hash))
1503 * This is a double for. Do not use 'break' to break out of the loop,
1504 * you must use a goto.
1506 #define do_for_each_ftrace_rec(pg, rec) \
1507 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1509 for (_____i = 0; _____i < pg->index; _____i++) { \
1510 rec = &pg->records[_____i];
1512 #define while_for_each_ftrace_rec() \
1517 static int ftrace_cmp_recs(const void *a, const void *b)
1519 const struct dyn_ftrace *key = a;
1520 const struct dyn_ftrace *rec = b;
1522 if (key->flags < rec->ip)
1524 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1529 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1531 struct ftrace_page *pg;
1532 struct dyn_ftrace *rec = NULL;
1533 struct dyn_ftrace key;
1536 key.flags = end; /* overload flags, as it is unsigned long */
1538 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1539 if (end < pg->records[0].ip ||
1540 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1542 rec = bsearch(&key, pg->records, pg->index,
1543 sizeof(struct dyn_ftrace),
1552 * ftrace_location_range - return the first address of a traced location
1553 * if it touches the given ip range
1554 * @start: start of range to search.
1555 * @end: end of range to search (inclusive). @end points to the last byte
1558 * Returns rec->ip if the related ftrace location is a least partly within
1559 * the given address range. That is, the first address of the instruction
1560 * that is either a NOP or call to the function tracer. It checks the ftrace
1561 * internal tables to determine if the address belongs or not.
1563 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1565 struct dyn_ftrace *rec;
1567 rec = lookup_rec(start, end);
1575 * ftrace_location - return true if the ip giving is a traced location
1576 * @ip: the instruction pointer to check
1578 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1579 * That is, the instruction that is either a NOP or call to
1580 * the function tracer. It checks the ftrace internal tables to
1581 * determine if the address belongs or not.
1583 unsigned long ftrace_location(unsigned long ip)
1585 return ftrace_location_range(ip, ip);
1589 * ftrace_text_reserved - return true if range contains an ftrace location
1590 * @start: start of range to search
1591 * @end: end of range to search (inclusive). @end points to the last byte to check.
1593 * Returns 1 if @start and @end contains a ftrace location.
1594 * That is, the instruction that is either a NOP or call to
1595 * the function tracer. It checks the ftrace internal tables to
1596 * determine if the address belongs or not.
1598 int ftrace_text_reserved(const void *start, const void *end)
1602 ret = ftrace_location_range((unsigned long)start,
1603 (unsigned long)end);
1608 /* Test if ops registered to this rec needs regs */
1609 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1611 struct ftrace_ops *ops;
1612 bool keep_regs = false;
1614 for (ops = ftrace_ops_list;
1615 ops != &ftrace_list_end; ops = ops->next) {
1616 /* pass rec in as regs to have non-NULL val */
1617 if (ftrace_ops_test(ops, rec->ip, rec)) {
1618 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1628 static struct ftrace_ops *
1629 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1630 static struct ftrace_ops *
1631 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1632 static struct ftrace_ops *
1633 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1635 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1639 struct ftrace_hash *hash;
1640 struct ftrace_hash *other_hash;
1641 struct ftrace_page *pg;
1642 struct dyn_ftrace *rec;
1643 bool update = false;
1647 /* Only update if the ops has been registered */
1648 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1652 * In the filter_hash case:
1653 * If the count is zero, we update all records.
1654 * Otherwise we just update the items in the hash.
1656 * In the notrace_hash case:
1657 * We enable the update in the hash.
1658 * As disabling notrace means enabling the tracing,
1659 * and enabling notrace means disabling, the inc variable
1663 hash = ops->func_hash->filter_hash;
1664 other_hash = ops->func_hash->notrace_hash;
1665 if (ftrace_hash_empty(hash))
1669 hash = ops->func_hash->notrace_hash;
1670 other_hash = ops->func_hash->filter_hash;
1672 * If the notrace hash has no items,
1673 * then there's nothing to do.
1675 if (ftrace_hash_empty(hash))
1679 do_for_each_ftrace_rec(pg, rec) {
1680 int in_other_hash = 0;
1684 if (rec->flags & FTRACE_FL_DISABLED)
1689 * Only the filter_hash affects all records.
1690 * Update if the record is not in the notrace hash.
1692 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1695 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1696 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1699 * If filter_hash is set, we want to match all functions
1700 * that are in the hash but not in the other hash.
1702 * If filter_hash is not set, then we are decrementing.
1703 * That means we match anything that is in the hash
1704 * and also in the other_hash. That is, we need to turn
1705 * off functions in the other hash because they are disabled
1708 if (filter_hash && in_hash && !in_other_hash)
1710 else if (!filter_hash && in_hash &&
1711 (in_other_hash || ftrace_hash_empty(other_hash)))
1719 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1722 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1723 rec->flags |= FTRACE_FL_DIRECT;
1726 * If there's only a single callback registered to a
1727 * function, and the ops has a trampoline registered
1728 * for it, then we can call it directly.
1730 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1731 rec->flags |= FTRACE_FL_TRAMP;
1734 * If we are adding another function callback
1735 * to this function, and the previous had a
1736 * custom trampoline in use, then we need to go
1737 * back to the default trampoline.
1739 rec->flags &= ~FTRACE_FL_TRAMP;
1742 * If any ops wants regs saved for this function
1743 * then all ops will get saved regs.
1745 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1746 rec->flags |= FTRACE_FL_REGS;
1748 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1753 * Only the internal direct_ops should have the
1754 * DIRECT flag set. Thus, if it is removing a
1755 * function, then that function should no longer
1758 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1759 rec->flags &= ~FTRACE_FL_DIRECT;
1762 * If the rec had REGS enabled and the ops that is
1763 * being removed had REGS set, then see if there is
1764 * still any ops for this record that wants regs.
1765 * If not, we can stop recording them.
1767 if (ftrace_rec_count(rec) > 0 &&
1768 rec->flags & FTRACE_FL_REGS &&
1769 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1770 if (!test_rec_ops_needs_regs(rec))
1771 rec->flags &= ~FTRACE_FL_REGS;
1775 * The TRAMP needs to be set only if rec count
1776 * is decremented to one, and the ops that is
1777 * left has a trampoline. As TRAMP can only be
1778 * enabled if there is only a single ops attached
1781 if (ftrace_rec_count(rec) == 1 &&
1782 ftrace_find_tramp_ops_any_other(rec, ops))
1783 rec->flags |= FTRACE_FL_TRAMP;
1785 rec->flags &= ~FTRACE_FL_TRAMP;
1788 * flags will be cleared in ftrace_check_record()
1789 * if rec count is zero.
1794 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1795 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1797 /* Shortcut, if we handled all records, we are done. */
1798 if (!all && count == hash->count)
1800 } while_for_each_ftrace_rec();
1805 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1808 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1811 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1814 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1817 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1818 int filter_hash, int inc)
1820 struct ftrace_ops *op;
1822 __ftrace_hash_rec_update(ops, filter_hash, inc);
1824 if (ops->func_hash != &global_ops.local_hash)
1828 * If the ops shares the global_ops hash, then we need to update
1829 * all ops that are enabled and use this hash.
1831 do_for_each_ftrace_op(op, ftrace_ops_list) {
1835 if (op->func_hash == &global_ops.local_hash)
1836 __ftrace_hash_rec_update(op, filter_hash, inc);
1837 } while_for_each_ftrace_op(op);
1840 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1843 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1846 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1849 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1853 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1854 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1855 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1856 * Note that old_hash and new_hash has below meanings
1857 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1858 * - If the hash is EMPTY_HASH, it hits nothing
1859 * - Anything else hits the recs which match the hash entries.
1861 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1862 struct ftrace_hash *old_hash,
1863 struct ftrace_hash *new_hash)
1865 struct ftrace_page *pg;
1866 struct dyn_ftrace *rec, *end = NULL;
1869 /* Only update if the ops has been registered */
1870 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1873 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1877 * Since the IPMODIFY is a very address sensitive action, we do not
1878 * allow ftrace_ops to set all functions to new hash.
1880 if (!new_hash || !old_hash)
1883 /* Update rec->flags */
1884 do_for_each_ftrace_rec(pg, rec) {
1886 if (rec->flags & FTRACE_FL_DISABLED)
1889 /* We need to update only differences of filter_hash */
1890 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1891 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1892 if (in_old == in_new)
1896 /* New entries must ensure no others are using it */
1897 if (rec->flags & FTRACE_FL_IPMODIFY)
1899 rec->flags |= FTRACE_FL_IPMODIFY;
1900 } else /* Removed entry */
1901 rec->flags &= ~FTRACE_FL_IPMODIFY;
1902 } while_for_each_ftrace_rec();
1909 /* Roll back what we did above */
1910 do_for_each_ftrace_rec(pg, rec) {
1912 if (rec->flags & FTRACE_FL_DISABLED)
1918 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1919 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1920 if (in_old == in_new)
1924 rec->flags &= ~FTRACE_FL_IPMODIFY;
1926 rec->flags |= FTRACE_FL_IPMODIFY;
1927 } while_for_each_ftrace_rec();
1933 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1935 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1937 if (ftrace_hash_empty(hash))
1940 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1943 /* Disabling always succeeds */
1944 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1946 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1948 if (ftrace_hash_empty(hash))
1951 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1954 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1955 struct ftrace_hash *new_hash)
1957 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1959 if (ftrace_hash_empty(old_hash))
1962 if (ftrace_hash_empty(new_hash))
1965 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1968 static void print_ip_ins(const char *fmt, const unsigned char *p)
1972 printk(KERN_CONT "%s", fmt);
1974 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1975 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1978 enum ftrace_bug_type ftrace_bug_type;
1979 const void *ftrace_expected;
1981 static void print_bug_type(void)
1983 switch (ftrace_bug_type) {
1984 case FTRACE_BUG_UNKNOWN:
1986 case FTRACE_BUG_INIT:
1987 pr_info("Initializing ftrace call sites\n");
1989 case FTRACE_BUG_NOP:
1990 pr_info("Setting ftrace call site to NOP\n");
1992 case FTRACE_BUG_CALL:
1993 pr_info("Setting ftrace call site to call ftrace function\n");
1995 case FTRACE_BUG_UPDATE:
1996 pr_info("Updating ftrace call site to call a different ftrace function\n");
2002 * ftrace_bug - report and shutdown function tracer
2003 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2004 * @rec: The record that failed
2006 * The arch code that enables or disables the function tracing
2007 * can call ftrace_bug() when it has detected a problem in
2008 * modifying the code. @failed should be one of either:
2009 * EFAULT - if the problem happens on reading the @ip address
2010 * EINVAL - if what is read at @ip is not what was expected
2011 * EPERM - if the problem happens on writing to the @ip address
2013 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2015 unsigned long ip = rec ? rec->ip : 0;
2017 pr_info("------------[ ftrace bug ]------------\n");
2021 pr_info("ftrace faulted on modifying ");
2022 print_ip_sym(KERN_INFO, ip);
2025 pr_info("ftrace failed to modify ");
2026 print_ip_sym(KERN_INFO, ip);
2027 print_ip_ins(" actual: ", (unsigned char *)ip);
2029 if (ftrace_expected) {
2030 print_ip_ins(" expected: ", ftrace_expected);
2035 pr_info("ftrace faulted on writing ");
2036 print_ip_sym(KERN_INFO, ip);
2039 pr_info("ftrace faulted on unknown error ");
2040 print_ip_sym(KERN_INFO, ip);
2044 struct ftrace_ops *ops = NULL;
2046 pr_info("ftrace record flags: %lx\n", rec->flags);
2047 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2048 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2049 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2050 ops = ftrace_find_tramp_ops_any(rec);
2053 pr_cont("\ttramp: %pS (%pS)",
2054 (void *)ops->trampoline,
2056 ops = ftrace_find_tramp_ops_next(rec, ops);
2059 pr_cont("\ttramp: ERROR!");
2062 ip = ftrace_get_addr_curr(rec);
2063 pr_cont("\n expected tramp: %lx\n", ip);
2066 FTRACE_WARN_ON_ONCE(1);
2069 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2071 unsigned long flag = 0UL;
2073 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2075 if (rec->flags & FTRACE_FL_DISABLED)
2076 return FTRACE_UPDATE_IGNORE;
2079 * If we are updating calls:
2081 * If the record has a ref count, then we need to enable it
2082 * because someone is using it.
2084 * Otherwise we make sure its disabled.
2086 * If we are disabling calls, then disable all records that
2089 if (enable && ftrace_rec_count(rec))
2090 flag = FTRACE_FL_ENABLED;
2093 * If enabling and the REGS flag does not match the REGS_EN, or
2094 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2095 * this record. Set flags to fail the compare against ENABLED.
2096 * Same for direct calls.
2099 if (!(rec->flags & FTRACE_FL_REGS) !=
2100 !(rec->flags & FTRACE_FL_REGS_EN))
2101 flag |= FTRACE_FL_REGS;
2103 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2104 !(rec->flags & FTRACE_FL_TRAMP_EN))
2105 flag |= FTRACE_FL_TRAMP;
2108 * Direct calls are special, as count matters.
2109 * We must test the record for direct, if the
2110 * DIRECT and DIRECT_EN do not match, but only
2111 * if the count is 1. That's because, if the
2112 * count is something other than one, we do not
2113 * want the direct enabled (it will be done via the
2114 * direct helper). But if DIRECT_EN is set, and
2115 * the count is not one, we need to clear it.
2117 if (ftrace_rec_count(rec) == 1) {
2118 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2119 !(rec->flags & FTRACE_FL_DIRECT_EN))
2120 flag |= FTRACE_FL_DIRECT;
2121 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2122 flag |= FTRACE_FL_DIRECT;
2126 /* If the state of this record hasn't changed, then do nothing */
2127 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2128 return FTRACE_UPDATE_IGNORE;
2131 /* Save off if rec is being enabled (for return value) */
2132 flag ^= rec->flags & FTRACE_FL_ENABLED;
2135 rec->flags |= FTRACE_FL_ENABLED;
2136 if (flag & FTRACE_FL_REGS) {
2137 if (rec->flags & FTRACE_FL_REGS)
2138 rec->flags |= FTRACE_FL_REGS_EN;
2140 rec->flags &= ~FTRACE_FL_REGS_EN;
2142 if (flag & FTRACE_FL_TRAMP) {
2143 if (rec->flags & FTRACE_FL_TRAMP)
2144 rec->flags |= FTRACE_FL_TRAMP_EN;
2146 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2149 if (flag & FTRACE_FL_DIRECT) {
2151 * If there's only one user (direct_ops helper)
2152 * then we can call the direct function
2153 * directly (no ftrace trampoline).
2155 if (ftrace_rec_count(rec) == 1) {
2156 if (rec->flags & FTRACE_FL_DIRECT)
2157 rec->flags |= FTRACE_FL_DIRECT_EN;
2159 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2162 * Can only call directly if there's
2163 * only one callback to the function.
2165 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2171 * If this record is being updated from a nop, then
2172 * return UPDATE_MAKE_CALL.
2174 * return UPDATE_MODIFY_CALL to tell the caller to convert
2175 * from the save regs, to a non-save regs function or
2176 * vice versa, or from a trampoline call.
2178 if (flag & FTRACE_FL_ENABLED) {
2179 ftrace_bug_type = FTRACE_BUG_CALL;
2180 return FTRACE_UPDATE_MAKE_CALL;
2183 ftrace_bug_type = FTRACE_BUG_UPDATE;
2184 return FTRACE_UPDATE_MODIFY_CALL;
2188 /* If there's no more users, clear all flags */
2189 if (!ftrace_rec_count(rec))
2193 * Just disable the record, but keep the ops TRAMP
2194 * and REGS states. The _EN flags must be disabled though.
2196 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2197 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2200 ftrace_bug_type = FTRACE_BUG_NOP;
2201 return FTRACE_UPDATE_MAKE_NOP;
2205 * ftrace_update_record, set a record that now is tracing or not
2206 * @rec: the record to update
2207 * @enable: set to true if the record is tracing, false to force disable
2209 * The records that represent all functions that can be traced need
2210 * to be updated when tracing has been enabled.
2212 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2214 return ftrace_check_record(rec, enable, true);
2218 * ftrace_test_record, check if the record has been enabled or not
2219 * @rec: the record to test
2220 * @enable: set to true to check if enabled, false if it is disabled
2222 * The arch code may need to test if a record is already set to
2223 * tracing to determine how to modify the function code that it
2226 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2228 return ftrace_check_record(rec, enable, false);
2231 static struct ftrace_ops *
2232 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2234 struct ftrace_ops *op;
2235 unsigned long ip = rec->ip;
2237 do_for_each_ftrace_op(op, ftrace_ops_list) {
2239 if (!op->trampoline)
2242 if (hash_contains_ip(ip, op->func_hash))
2244 } while_for_each_ftrace_op(op);
2249 static struct ftrace_ops *
2250 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2252 struct ftrace_ops *op;
2253 unsigned long ip = rec->ip;
2255 do_for_each_ftrace_op(op, ftrace_ops_list) {
2257 if (op == op_exclude || !op->trampoline)
2260 if (hash_contains_ip(ip, op->func_hash))
2262 } while_for_each_ftrace_op(op);
2267 static struct ftrace_ops *
2268 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2269 struct ftrace_ops *op)
2271 unsigned long ip = rec->ip;
2273 while_for_each_ftrace_op(op) {
2275 if (!op->trampoline)
2278 if (hash_contains_ip(ip, op->func_hash))
2285 static struct ftrace_ops *
2286 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2288 struct ftrace_ops *op;
2289 unsigned long ip = rec->ip;
2292 * Need to check removed ops first.
2293 * If they are being removed, and this rec has a tramp,
2294 * and this rec is in the ops list, then it would be the
2295 * one with the tramp.
2298 if (hash_contains_ip(ip, &removed_ops->old_hash))
2303 * Need to find the current trampoline for a rec.
2304 * Now, a trampoline is only attached to a rec if there
2305 * was a single 'ops' attached to it. But this can be called
2306 * when we are adding another op to the rec or removing the
2307 * current one. Thus, if the op is being added, we can
2308 * ignore it because it hasn't attached itself to the rec
2311 * If an ops is being modified (hooking to different functions)
2312 * then we don't care about the new functions that are being
2313 * added, just the old ones (that are probably being removed).
2315 * If we are adding an ops to a function that already is using
2316 * a trampoline, it needs to be removed (trampolines are only
2317 * for single ops connected), then an ops that is not being
2318 * modified also needs to be checked.
2320 do_for_each_ftrace_op(op, ftrace_ops_list) {
2322 if (!op->trampoline)
2326 * If the ops is being added, it hasn't gotten to
2327 * the point to be removed from this tree yet.
2329 if (op->flags & FTRACE_OPS_FL_ADDING)
2334 * If the ops is being modified and is in the old
2335 * hash, then it is probably being removed from this
2338 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2339 hash_contains_ip(ip, &op->old_hash))
2342 * If the ops is not being added or modified, and it's
2343 * in its normal filter hash, then this must be the one
2346 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2347 hash_contains_ip(ip, op->func_hash))
2350 } while_for_each_ftrace_op(op);
2355 static struct ftrace_ops *
2356 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2358 struct ftrace_ops *op;
2359 unsigned long ip = rec->ip;
2361 do_for_each_ftrace_op(op, ftrace_ops_list) {
2362 /* pass rec in as regs to have non-NULL val */
2363 if (hash_contains_ip(ip, op->func_hash))
2365 } while_for_each_ftrace_op(op);
2370 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2371 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2372 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2373 static DEFINE_MUTEX(direct_mutex);
2374 int ftrace_direct_func_count;
2377 * Search the direct_functions hash to see if the given instruction pointer
2378 * has a direct caller attached to it.
2380 unsigned long ftrace_find_rec_direct(unsigned long ip)
2382 struct ftrace_func_entry *entry;
2384 entry = __ftrace_lookup_ip(direct_functions, ip);
2388 return entry->direct;
2391 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2392 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2394 struct pt_regs *regs = ftrace_get_regs(fregs);
2397 addr = ftrace_find_rec_direct(ip);
2401 arch_ftrace_set_direct_caller(regs, addr);
2404 struct ftrace_ops direct_ops = {
2405 .func = call_direct_funcs,
2406 .flags = FTRACE_OPS_FL_IPMODIFY
2407 | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2408 | FTRACE_OPS_FL_PERMANENT,
2410 * By declaring the main trampoline as this trampoline
2411 * it will never have one allocated for it. Allocated
2412 * trampolines should not call direct functions.
2413 * The direct_ops should only be called by the builtin
2414 * ftrace_regs_caller trampoline.
2416 .trampoline = FTRACE_REGS_ADDR,
2418 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2421 * ftrace_get_addr_new - Get the call address to set to
2422 * @rec: The ftrace record descriptor
2424 * If the record has the FTRACE_FL_REGS set, that means that it
2425 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2426 * is not set, then it wants to convert to the normal callback.
2428 * Returns the address of the trampoline to set to
2430 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2432 struct ftrace_ops *ops;
2435 if ((rec->flags & FTRACE_FL_DIRECT) &&
2436 (ftrace_rec_count(rec) == 1)) {
2437 addr = ftrace_find_rec_direct(rec->ip);
2443 /* Trampolines take precedence over regs */
2444 if (rec->flags & FTRACE_FL_TRAMP) {
2445 ops = ftrace_find_tramp_ops_new(rec);
2446 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2447 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2448 (void *)rec->ip, (void *)rec->ip, rec->flags);
2449 /* Ftrace is shutting down, return anything */
2450 return (unsigned long)FTRACE_ADDR;
2452 return ops->trampoline;
2455 if (rec->flags & FTRACE_FL_REGS)
2456 return (unsigned long)FTRACE_REGS_ADDR;
2458 return (unsigned long)FTRACE_ADDR;
2462 * ftrace_get_addr_curr - Get the call address that is already there
2463 * @rec: The ftrace record descriptor
2465 * The FTRACE_FL_REGS_EN is set when the record already points to
2466 * a function that saves all the regs. Basically the '_EN' version
2467 * represents the current state of the function.
2469 * Returns the address of the trampoline that is currently being called
2471 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2473 struct ftrace_ops *ops;
2476 /* Direct calls take precedence over trampolines */
2477 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2478 addr = ftrace_find_rec_direct(rec->ip);
2484 /* Trampolines take precedence over regs */
2485 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2486 ops = ftrace_find_tramp_ops_curr(rec);
2487 if (FTRACE_WARN_ON(!ops)) {
2488 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2489 (void *)rec->ip, (void *)rec->ip);
2490 /* Ftrace is shutting down, return anything */
2491 return (unsigned long)FTRACE_ADDR;
2493 return ops->trampoline;
2496 if (rec->flags & FTRACE_FL_REGS_EN)
2497 return (unsigned long)FTRACE_REGS_ADDR;
2499 return (unsigned long)FTRACE_ADDR;
2503 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2505 unsigned long ftrace_old_addr;
2506 unsigned long ftrace_addr;
2509 ftrace_addr = ftrace_get_addr_new(rec);
2511 /* This needs to be done before we call ftrace_update_record */
2512 ftrace_old_addr = ftrace_get_addr_curr(rec);
2514 ret = ftrace_update_record(rec, enable);
2516 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2519 case FTRACE_UPDATE_IGNORE:
2522 case FTRACE_UPDATE_MAKE_CALL:
2523 ftrace_bug_type = FTRACE_BUG_CALL;
2524 return ftrace_make_call(rec, ftrace_addr);
2526 case FTRACE_UPDATE_MAKE_NOP:
2527 ftrace_bug_type = FTRACE_BUG_NOP;
2528 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2530 case FTRACE_UPDATE_MODIFY_CALL:
2531 ftrace_bug_type = FTRACE_BUG_UPDATE;
2532 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2535 return -1; /* unknown ftrace bug */
2538 void __weak ftrace_replace_code(int mod_flags)
2540 struct dyn_ftrace *rec;
2541 struct ftrace_page *pg;
2542 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2543 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2546 if (unlikely(ftrace_disabled))
2549 do_for_each_ftrace_rec(pg, rec) {
2551 if (rec->flags & FTRACE_FL_DISABLED)
2554 failed = __ftrace_replace_code(rec, enable);
2556 ftrace_bug(failed, rec);
2557 /* Stop processing */
2562 } while_for_each_ftrace_rec();
2565 struct ftrace_rec_iter {
2566 struct ftrace_page *pg;
2571 * ftrace_rec_iter_start, start up iterating over traced functions
2573 * Returns an iterator handle that is used to iterate over all
2574 * the records that represent address locations where functions
2577 * May return NULL if no records are available.
2579 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2582 * We only use a single iterator.
2583 * Protected by the ftrace_lock mutex.
2585 static struct ftrace_rec_iter ftrace_rec_iter;
2586 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2588 iter->pg = ftrace_pages_start;
2591 /* Could have empty pages */
2592 while (iter->pg && !iter->pg->index)
2593 iter->pg = iter->pg->next;
2602 * ftrace_rec_iter_next, get the next record to process.
2603 * @iter: The handle to the iterator.
2605 * Returns the next iterator after the given iterator @iter.
2607 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2611 if (iter->index >= iter->pg->index) {
2612 iter->pg = iter->pg->next;
2615 /* Could have empty pages */
2616 while (iter->pg && !iter->pg->index)
2617 iter->pg = iter->pg->next;
2627 * ftrace_rec_iter_record, get the record at the iterator location
2628 * @iter: The current iterator location
2630 * Returns the record that the current @iter is at.
2632 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2634 return &iter->pg->records[iter->index];
2638 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2642 if (unlikely(ftrace_disabled))
2645 ret = ftrace_init_nop(mod, rec);
2647 ftrace_bug_type = FTRACE_BUG_INIT;
2648 ftrace_bug(ret, rec);
2655 * archs can override this function if they must do something
2656 * before the modifying code is performed.
2658 int __weak ftrace_arch_code_modify_prepare(void)
2664 * archs can override this function if they must do something
2665 * after the modifying code is performed.
2667 int __weak ftrace_arch_code_modify_post_process(void)
2672 void ftrace_modify_all_code(int command)
2674 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2678 if (command & FTRACE_MAY_SLEEP)
2679 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2682 * If the ftrace_caller calls a ftrace_ops func directly,
2683 * we need to make sure that it only traces functions it
2684 * expects to trace. When doing the switch of functions,
2685 * we need to update to the ftrace_ops_list_func first
2686 * before the transition between old and new calls are set,
2687 * as the ftrace_ops_list_func will check the ops hashes
2688 * to make sure the ops are having the right functions
2692 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2693 if (FTRACE_WARN_ON(err))
2697 if (command & FTRACE_UPDATE_CALLS)
2698 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2699 else if (command & FTRACE_DISABLE_CALLS)
2700 ftrace_replace_code(mod_flags);
2702 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2703 function_trace_op = set_function_trace_op;
2705 /* If irqs are disabled, we are in stop machine */
2706 if (!irqs_disabled())
2707 smp_call_function(ftrace_sync_ipi, NULL, 1);
2708 err = ftrace_update_ftrace_func(ftrace_trace_function);
2709 if (FTRACE_WARN_ON(err))
2713 if (command & FTRACE_START_FUNC_RET)
2714 err = ftrace_enable_ftrace_graph_caller();
2715 else if (command & FTRACE_STOP_FUNC_RET)
2716 err = ftrace_disable_ftrace_graph_caller();
2717 FTRACE_WARN_ON(err);
2720 static int __ftrace_modify_code(void *data)
2722 int *command = data;
2724 ftrace_modify_all_code(*command);
2730 * ftrace_run_stop_machine, go back to the stop machine method
2731 * @command: The command to tell ftrace what to do
2733 * If an arch needs to fall back to the stop machine method, the
2734 * it can call this function.
2736 void ftrace_run_stop_machine(int command)
2738 stop_machine(__ftrace_modify_code, &command, NULL);
2742 * arch_ftrace_update_code, modify the code to trace or not trace
2743 * @command: The command that needs to be done
2745 * Archs can override this function if it does not need to
2746 * run stop_machine() to modify code.
2748 void __weak arch_ftrace_update_code(int command)
2750 ftrace_run_stop_machine(command);
2753 static void ftrace_run_update_code(int command)
2757 ret = ftrace_arch_code_modify_prepare();
2758 FTRACE_WARN_ON(ret);
2763 * By default we use stop_machine() to modify the code.
2764 * But archs can do what ever they want as long as it
2765 * is safe. The stop_machine() is the safest, but also
2766 * produces the most overhead.
2768 arch_ftrace_update_code(command);
2770 ret = ftrace_arch_code_modify_post_process();
2771 FTRACE_WARN_ON(ret);
2774 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2775 struct ftrace_ops_hash *old_hash)
2777 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2778 ops->old_hash.filter_hash = old_hash->filter_hash;
2779 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2780 ftrace_run_update_code(command);
2781 ops->old_hash.filter_hash = NULL;
2782 ops->old_hash.notrace_hash = NULL;
2783 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2786 static ftrace_func_t saved_ftrace_func;
2787 static int ftrace_start_up;
2789 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2793 /* List of trace_ops that have allocated trampolines */
2794 static LIST_HEAD(ftrace_ops_trampoline_list);
2796 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2798 lockdep_assert_held(&ftrace_lock);
2799 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2802 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2804 lockdep_assert_held(&ftrace_lock);
2805 list_del_rcu(&ops->list);
2810 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2811 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2814 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2815 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2817 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2819 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2822 * Record the text poke event before the ksymbol unregister
2825 perf_event_text_poke((void *)ops->trampoline,
2826 (void *)ops->trampoline,
2827 ops->trampoline_size, NULL, 0);
2828 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2829 ops->trampoline, ops->trampoline_size,
2830 true, FTRACE_TRAMPOLINE_SYM);
2831 /* Remove from kallsyms after the perf events */
2832 ftrace_remove_trampoline_from_kallsyms(ops);
2835 arch_ftrace_trampoline_free(ops);
2838 static void ftrace_startup_enable(int command)
2840 if (saved_ftrace_func != ftrace_trace_function) {
2841 saved_ftrace_func = ftrace_trace_function;
2842 command |= FTRACE_UPDATE_TRACE_FUNC;
2845 if (!command || !ftrace_enabled)
2848 ftrace_run_update_code(command);
2851 static void ftrace_startup_all(int command)
2853 update_all_ops = true;
2854 ftrace_startup_enable(command);
2855 update_all_ops = false;
2858 int ftrace_startup(struct ftrace_ops *ops, int command)
2862 if (unlikely(ftrace_disabled))
2865 ret = __register_ftrace_function(ops);
2872 * Note that ftrace probes uses this to start up
2873 * and modify functions it will probe. But we still
2874 * set the ADDING flag for modification, as probes
2875 * do not have trampolines. If they add them in the
2876 * future, then the probes will need to distinguish
2877 * between adding and updating probes.
2879 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2881 ret = ftrace_hash_ipmodify_enable(ops);
2883 /* Rollback registration process */
2884 __unregister_ftrace_function(ops);
2886 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2887 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2888 ftrace_trampoline_free(ops);
2892 if (ftrace_hash_rec_enable(ops, 1))
2893 command |= FTRACE_UPDATE_CALLS;
2895 ftrace_startup_enable(command);
2897 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2902 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2906 if (unlikely(ftrace_disabled))
2909 ret = __unregister_ftrace_function(ops);
2915 * Just warn in case of unbalance, no need to kill ftrace, it's not
2916 * critical but the ftrace_call callers may be never nopped again after
2917 * further ftrace uses.
2919 WARN_ON_ONCE(ftrace_start_up < 0);
2921 /* Disabling ipmodify never fails */
2922 ftrace_hash_ipmodify_disable(ops);
2924 if (ftrace_hash_rec_disable(ops, 1))
2925 command |= FTRACE_UPDATE_CALLS;
2927 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2929 if (saved_ftrace_func != ftrace_trace_function) {
2930 saved_ftrace_func = ftrace_trace_function;
2931 command |= FTRACE_UPDATE_TRACE_FUNC;
2934 if (!command || !ftrace_enabled) {
2936 * If these are dynamic or per_cpu ops, they still
2937 * need their data freed. Since, function tracing is
2938 * not currently active, we can just free them
2939 * without synchronizing all CPUs.
2941 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2948 * If the ops uses a trampoline, then it needs to be
2949 * tested first on update.
2951 ops->flags |= FTRACE_OPS_FL_REMOVING;
2954 /* The trampoline logic checks the old hashes */
2955 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2956 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2958 ftrace_run_update_code(command);
2961 * If there's no more ops registered with ftrace, run a
2962 * sanity check to make sure all rec flags are cleared.
2964 if (rcu_dereference_protected(ftrace_ops_list,
2965 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2966 struct ftrace_page *pg;
2967 struct dyn_ftrace *rec;
2969 do_for_each_ftrace_rec(pg, rec) {
2970 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2971 pr_warn(" %pS flags:%lx\n",
2972 (void *)rec->ip, rec->flags);
2973 } while_for_each_ftrace_rec();
2976 ops->old_hash.filter_hash = NULL;
2977 ops->old_hash.notrace_hash = NULL;
2980 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2983 * Dynamic ops may be freed, we must make sure that all
2984 * callers are done before leaving this function.
2985 * The same goes for freeing the per_cpu data of the per_cpu
2988 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2990 * We need to do a hard force of sched synchronization.
2991 * This is because we use preempt_disable() to do RCU, but
2992 * the function tracers can be called where RCU is not watching
2993 * (like before user_exit()). We can not rely on the RCU
2994 * infrastructure to do the synchronization, thus we must do it
2997 synchronize_rcu_tasks_rude();
3000 * When the kernel is preemptive, tasks can be preempted
3001 * while on a ftrace trampoline. Just scheduling a task on
3002 * a CPU is not good enough to flush them. Calling
3003 * synchornize_rcu_tasks() will wait for those tasks to
3004 * execute and either schedule voluntarily or enter user space.
3006 if (IS_ENABLED(CONFIG_PREEMPTION))
3007 synchronize_rcu_tasks();
3010 ftrace_trampoline_free(ops);
3016 static void ftrace_startup_sysctl(void)
3020 if (unlikely(ftrace_disabled))
3023 /* Force update next time */
3024 saved_ftrace_func = NULL;
3025 /* ftrace_start_up is true if we want ftrace running */
3026 if (ftrace_start_up) {
3027 command = FTRACE_UPDATE_CALLS;
3028 if (ftrace_graph_active)
3029 command |= FTRACE_START_FUNC_RET;
3030 ftrace_startup_enable(command);
3034 static void ftrace_shutdown_sysctl(void)
3038 if (unlikely(ftrace_disabled))
3041 /* ftrace_start_up is true if ftrace is running */
3042 if (ftrace_start_up) {
3043 command = FTRACE_DISABLE_CALLS;
3044 if (ftrace_graph_active)
3045 command |= FTRACE_STOP_FUNC_RET;
3046 ftrace_run_update_code(command);
3050 static u64 ftrace_update_time;
3051 unsigned long ftrace_update_tot_cnt;
3052 unsigned long ftrace_number_of_pages;
3053 unsigned long ftrace_number_of_groups;
3055 static inline int ops_traces_mod(struct ftrace_ops *ops)
3058 * Filter_hash being empty will default to trace module.
3059 * But notrace hash requires a test of individual module functions.
3061 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3062 ftrace_hash_empty(ops->func_hash->notrace_hash);
3066 * Check if the current ops references the record.
3068 * If the ops traces all functions, then it was already accounted for.
3069 * If the ops does not trace the current record function, skip it.
3070 * If the ops ignores the function via notrace filter, skip it.
3073 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3075 /* If ops isn't enabled, ignore it */
3076 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3079 /* If ops traces all then it includes this function */
3080 if (ops_traces_mod(ops))
3083 /* The function must be in the filter */
3084 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3085 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3088 /* If in notrace hash, we ignore it too */
3089 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3095 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3097 struct ftrace_page *pg;
3098 struct dyn_ftrace *p;
3100 unsigned long update_cnt = 0;
3101 unsigned long rec_flags = 0;
3104 start = ftrace_now(raw_smp_processor_id());
3107 * When a module is loaded, this function is called to convert
3108 * the calls to mcount in its text to nops, and also to create
3109 * an entry in the ftrace data. Now, if ftrace is activated
3110 * after this call, but before the module sets its text to
3111 * read-only, the modification of enabling ftrace can fail if
3112 * the read-only is done while ftrace is converting the calls.
3113 * To prevent this, the module's records are set as disabled
3114 * and will be enabled after the call to set the module's text
3118 rec_flags |= FTRACE_FL_DISABLED;
3120 for (pg = new_pgs; pg; pg = pg->next) {
3122 for (i = 0; i < pg->index; i++) {
3124 /* If something went wrong, bail without enabling anything */
3125 if (unlikely(ftrace_disabled))
3128 p = &pg->records[i];
3129 p->flags = rec_flags;
3132 * Do the initial record conversion from mcount jump
3133 * to the NOP instructions.
3135 if (!__is_defined(CC_USING_NOP_MCOUNT) &&
3136 !ftrace_nop_initialize(mod, p))
3143 stop = ftrace_now(raw_smp_processor_id());
3144 ftrace_update_time = stop - start;
3145 ftrace_update_tot_cnt += update_cnt;
3150 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3156 if (WARN_ON(!count))
3159 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3160 order = get_count_order(pages);
3163 * We want to fill as much as possible. No more than a page
3166 if (!is_power_of_2(pages))
3170 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3173 /* if we can't allocate this size, try something smaller */
3180 ftrace_number_of_pages += 1 << order;
3181 ftrace_number_of_groups++;
3183 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3192 static struct ftrace_page *
3193 ftrace_allocate_pages(unsigned long num_to_init)
3195 struct ftrace_page *start_pg;
3196 struct ftrace_page *pg;
3203 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3208 * Try to allocate as much as possible in one continues
3209 * location that fills in all of the space. We want to
3210 * waste as little space as possible.
3213 cnt = ftrace_allocate_records(pg, num_to_init);
3221 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3233 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3235 free_pages((unsigned long)pg->records, order);
3236 start_pg = pg->next;
3239 ftrace_number_of_pages -= 1 << order;
3240 ftrace_number_of_groups--;
3242 pr_info("ftrace: FAILED to allocate memory for functions\n");
3246 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3248 struct ftrace_iterator {
3252 struct ftrace_page *pg;
3253 struct dyn_ftrace *func;
3254 struct ftrace_func_probe *probe;
3255 struct ftrace_func_entry *probe_entry;
3256 struct trace_parser parser;
3257 struct ftrace_hash *hash;
3258 struct ftrace_ops *ops;
3259 struct trace_array *tr;
3260 struct list_head *mod_list;
3267 t_probe_next(struct seq_file *m, loff_t *pos)
3269 struct ftrace_iterator *iter = m->private;
3270 struct trace_array *tr = iter->ops->private;
3271 struct list_head *func_probes;
3272 struct ftrace_hash *hash;
3273 struct list_head *next;
3274 struct hlist_node *hnd = NULL;
3275 struct hlist_head *hhd;
3284 func_probes = &tr->func_probes;
3285 if (list_empty(func_probes))
3289 next = func_probes->next;
3290 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3293 if (iter->probe_entry)
3294 hnd = &iter->probe_entry->hlist;
3296 hash = iter->probe->ops.func_hash->filter_hash;
3299 * A probe being registered may temporarily have an empty hash
3300 * and it's at the end of the func_probes list.
3302 if (!hash || hash == EMPTY_HASH)
3305 size = 1 << hash->size_bits;
3308 if (iter->pidx >= size) {
3309 if (iter->probe->list.next == func_probes)
3311 next = iter->probe->list.next;
3312 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3313 hash = iter->probe->ops.func_hash->filter_hash;
3314 size = 1 << hash->size_bits;
3318 hhd = &hash->buckets[iter->pidx];
3320 if (hlist_empty(hhd)) {
3336 if (WARN_ON_ONCE(!hnd))
3339 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3344 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3346 struct ftrace_iterator *iter = m->private;
3350 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3353 if (iter->mod_pos > *pos)
3357 iter->probe_entry = NULL;
3359 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3360 p = t_probe_next(m, &l);
3367 /* Only set this if we have an item */
3368 iter->flags |= FTRACE_ITER_PROBE;
3374 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3376 struct ftrace_func_entry *probe_entry;
3377 struct ftrace_probe_ops *probe_ops;
3378 struct ftrace_func_probe *probe;
3380 probe = iter->probe;
3381 probe_entry = iter->probe_entry;
3383 if (WARN_ON_ONCE(!probe || !probe_entry))
3386 probe_ops = probe->probe_ops;
3388 if (probe_ops->print)
3389 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3391 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3392 (void *)probe_ops->func);
3398 t_mod_next(struct seq_file *m, loff_t *pos)
3400 struct ftrace_iterator *iter = m->private;
3401 struct trace_array *tr = iter->tr;
3406 iter->mod_list = iter->mod_list->next;
3408 if (iter->mod_list == &tr->mod_trace ||
3409 iter->mod_list == &tr->mod_notrace) {
3410 iter->flags &= ~FTRACE_ITER_MOD;
3414 iter->mod_pos = *pos;
3419 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3421 struct ftrace_iterator *iter = m->private;
3425 if (iter->func_pos > *pos)
3428 iter->mod_pos = iter->func_pos;
3430 /* probes are only available if tr is set */
3434 for (l = 0; l <= (*pos - iter->func_pos); ) {
3435 p = t_mod_next(m, &l);
3440 iter->flags &= ~FTRACE_ITER_MOD;
3441 return t_probe_start(m, pos);
3444 /* Only set this if we have an item */
3445 iter->flags |= FTRACE_ITER_MOD;
3451 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3453 struct ftrace_mod_load *ftrace_mod;
3454 struct trace_array *tr = iter->tr;
3456 if (WARN_ON_ONCE(!iter->mod_list) ||
3457 iter->mod_list == &tr->mod_trace ||
3458 iter->mod_list == &tr->mod_notrace)
3461 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3463 if (ftrace_mod->func)
3464 seq_printf(m, "%s", ftrace_mod->func);
3468 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3474 t_func_next(struct seq_file *m, loff_t *pos)
3476 struct ftrace_iterator *iter = m->private;
3477 struct dyn_ftrace *rec = NULL;
3482 if (iter->idx >= iter->pg->index) {
3483 if (iter->pg->next) {
3484 iter->pg = iter->pg->next;
3489 rec = &iter->pg->records[iter->idx++];
3490 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3491 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3493 ((iter->flags & FTRACE_ITER_ENABLED) &&
3494 !(rec->flags & FTRACE_FL_ENABLED))) {
3504 iter->pos = iter->func_pos = *pos;
3511 t_next(struct seq_file *m, void *v, loff_t *pos)
3513 struct ftrace_iterator *iter = m->private;
3514 loff_t l = *pos; /* t_probe_start() must use original pos */
3517 if (unlikely(ftrace_disabled))
3520 if (iter->flags & FTRACE_ITER_PROBE)
3521 return t_probe_next(m, pos);
3523 if (iter->flags & FTRACE_ITER_MOD)
3524 return t_mod_next(m, pos);
3526 if (iter->flags & FTRACE_ITER_PRINTALL) {
3527 /* next must increment pos, and t_probe_start does not */
3529 return t_mod_start(m, &l);
3532 ret = t_func_next(m, pos);
3535 return t_mod_start(m, &l);
3540 static void reset_iter_read(struct ftrace_iterator *iter)
3544 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3547 static void *t_start(struct seq_file *m, loff_t *pos)
3549 struct ftrace_iterator *iter = m->private;
3553 mutex_lock(&ftrace_lock);
3555 if (unlikely(ftrace_disabled))
3559 * If an lseek was done, then reset and start from beginning.
3561 if (*pos < iter->pos)
3562 reset_iter_read(iter);
3565 * For set_ftrace_filter reading, if we have the filter
3566 * off, we can short cut and just print out that all
3567 * functions are enabled.
3569 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3570 ftrace_hash_empty(iter->hash)) {
3571 iter->func_pos = 1; /* Account for the message */
3573 return t_mod_start(m, pos);
3574 iter->flags |= FTRACE_ITER_PRINTALL;
3575 /* reset in case of seek/pread */
3576 iter->flags &= ~FTRACE_ITER_PROBE;
3580 if (iter->flags & FTRACE_ITER_MOD)
3581 return t_mod_start(m, pos);
3584 * Unfortunately, we need to restart at ftrace_pages_start
3585 * every time we let go of the ftrace_mutex. This is because
3586 * those pointers can change without the lock.
3588 iter->pg = ftrace_pages_start;
3590 for (l = 0; l <= *pos; ) {
3591 p = t_func_next(m, &l);
3597 return t_mod_start(m, pos);
3602 static void t_stop(struct seq_file *m, void *p)
3604 mutex_unlock(&ftrace_lock);
3608 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3613 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3614 struct dyn_ftrace *rec)
3618 ptr = arch_ftrace_trampoline_func(ops, rec);
3620 seq_printf(m, " ->%pS", ptr);
3623 static int t_show(struct seq_file *m, void *v)
3625 struct ftrace_iterator *iter = m->private;
3626 struct dyn_ftrace *rec;
3628 if (iter->flags & FTRACE_ITER_PROBE)
3629 return t_probe_show(m, iter);
3631 if (iter->flags & FTRACE_ITER_MOD)
3632 return t_mod_show(m, iter);
3634 if (iter->flags & FTRACE_ITER_PRINTALL) {
3635 if (iter->flags & FTRACE_ITER_NOTRACE)
3636 seq_puts(m, "#### no functions disabled ####\n");
3638 seq_puts(m, "#### all functions enabled ####\n");
3647 seq_printf(m, "%ps", (void *)rec->ip);
3648 if (iter->flags & FTRACE_ITER_ENABLED) {
3649 struct ftrace_ops *ops;
3651 seq_printf(m, " (%ld)%s%s%s",
3652 ftrace_rec_count(rec),
3653 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3654 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3655 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3656 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3657 ops = ftrace_find_tramp_ops_any(rec);
3660 seq_printf(m, "\ttramp: %pS (%pS)",
3661 (void *)ops->trampoline,
3663 add_trampoline_func(m, ops, rec);
3664 ops = ftrace_find_tramp_ops_next(rec, ops);
3667 seq_puts(m, "\ttramp: ERROR!");
3669 add_trampoline_func(m, NULL, rec);
3671 if (rec->flags & FTRACE_FL_DIRECT) {
3672 unsigned long direct;
3674 direct = ftrace_find_rec_direct(rec->ip);
3676 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3685 static const struct seq_operations show_ftrace_seq_ops = {
3693 ftrace_avail_open(struct inode *inode, struct file *file)
3695 struct ftrace_iterator *iter;
3698 ret = security_locked_down(LOCKDOWN_TRACEFS);
3702 if (unlikely(ftrace_disabled))
3705 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3709 iter->pg = ftrace_pages_start;
3710 iter->ops = &global_ops;
3716 ftrace_enabled_open(struct inode *inode, struct file *file)
3718 struct ftrace_iterator *iter;
3721 * This shows us what functions are currently being
3722 * traced and by what. Not sure if we want lockdown
3723 * to hide such critical information for an admin.
3724 * Although, perhaps it can show information we don't
3725 * want people to see, but if something is tracing
3726 * something, we probably want to know about it.
3729 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3733 iter->pg = ftrace_pages_start;
3734 iter->flags = FTRACE_ITER_ENABLED;
3735 iter->ops = &global_ops;
3741 * ftrace_regex_open - initialize function tracer filter files
3742 * @ops: The ftrace_ops that hold the hash filters
3743 * @flag: The type of filter to process
3744 * @inode: The inode, usually passed in to your open routine
3745 * @file: The file, usually passed in to your open routine
3747 * ftrace_regex_open() initializes the filter files for the
3748 * @ops. Depending on @flag it may process the filter hash or
3749 * the notrace hash of @ops. With this called from the open
3750 * routine, you can use ftrace_filter_write() for the write
3751 * routine if @flag has FTRACE_ITER_FILTER set, or
3752 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3753 * tracing_lseek() should be used as the lseek routine, and
3754 * release must call ftrace_regex_release().
3757 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3758 struct inode *inode, struct file *file)
3760 struct ftrace_iterator *iter;
3761 struct ftrace_hash *hash;
3762 struct list_head *mod_head;
3763 struct trace_array *tr = ops->private;
3766 ftrace_ops_init(ops);
3768 if (unlikely(ftrace_disabled))
3771 if (tracing_check_open_get_tr(tr))
3774 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3778 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3785 mutex_lock(&ops->func_hash->regex_lock);
3787 if (flag & FTRACE_ITER_NOTRACE) {
3788 hash = ops->func_hash->notrace_hash;
3789 mod_head = tr ? &tr->mod_notrace : NULL;
3791 hash = ops->func_hash->filter_hash;
3792 mod_head = tr ? &tr->mod_trace : NULL;
3795 iter->mod_list = mod_head;
3797 if (file->f_mode & FMODE_WRITE) {
3798 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3800 if (file->f_flags & O_TRUNC) {
3801 iter->hash = alloc_ftrace_hash(size_bits);
3802 clear_ftrace_mod_list(mod_head);
3804 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3808 trace_parser_put(&iter->parser);
3816 if (file->f_mode & FMODE_READ) {
3817 iter->pg = ftrace_pages_start;
3819 ret = seq_open(file, &show_ftrace_seq_ops);
3821 struct seq_file *m = file->private_data;
3825 free_ftrace_hash(iter->hash);
3826 trace_parser_put(&iter->parser);
3829 file->private_data = iter;
3832 mutex_unlock(&ops->func_hash->regex_lock);
3838 trace_array_put(tr);
3845 ftrace_filter_open(struct inode *inode, struct file *file)
3847 struct ftrace_ops *ops = inode->i_private;
3849 /* Checks for tracefs lockdown */
3850 return ftrace_regex_open(ops,
3851 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3856 ftrace_notrace_open(struct inode *inode, struct file *file)
3858 struct ftrace_ops *ops = inode->i_private;
3860 /* Checks for tracefs lockdown */
3861 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3865 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3866 struct ftrace_glob {
3873 * If symbols in an architecture don't correspond exactly to the user-visible
3874 * name of what they represent, it is possible to define this function to
3875 * perform the necessary adjustments.
3877 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3882 static int ftrace_match(char *str, struct ftrace_glob *g)
3887 str = arch_ftrace_match_adjust(str, g->search);
3891 if (strcmp(str, g->search) == 0)
3894 case MATCH_FRONT_ONLY:
3895 if (strncmp(str, g->search, g->len) == 0)
3898 case MATCH_MIDDLE_ONLY:
3899 if (strstr(str, g->search))
3902 case MATCH_END_ONLY:
3904 if (slen >= g->len &&
3905 memcmp(str + slen - g->len, g->search, g->len) == 0)
3909 if (glob_match(g->search, str))
3918 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3920 struct ftrace_func_entry *entry;
3923 entry = ftrace_lookup_ip(hash, rec->ip);
3925 /* Do nothing if it doesn't exist */
3929 free_hash_entry(hash, entry);
3931 /* Do nothing if it exists */
3935 ret = add_hash_entry(hash, rec->ip);
3941 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3944 long index = simple_strtoul(func_g->search, NULL, 0);
3945 struct ftrace_page *pg;
3946 struct dyn_ftrace *rec;
3948 /* The index starts at 1 */
3952 do_for_each_ftrace_rec(pg, rec) {
3953 if (pg->index <= index) {
3955 /* this is a double loop, break goes to the next page */
3958 rec = &pg->records[index];
3959 enter_record(hash, rec, clear_filter);
3961 } while_for_each_ftrace_rec();
3966 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3967 struct ftrace_glob *mod_g, int exclude_mod)
3969 char str[KSYM_SYMBOL_LEN];
3972 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3975 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3977 /* blank module name to match all modules */
3979 /* blank module globbing: modname xor exclude_mod */
3980 if (!exclude_mod != !modname)
3986 * exclude_mod is set to trace everything but the given
3987 * module. If it is set and the module matches, then
3988 * return 0. If it is not set, and the module doesn't match
3989 * also return 0. Otherwise, check the function to see if
3992 if (!mod_matches == !exclude_mod)
3995 /* blank search means to match all funcs in the mod */
4000 return ftrace_match(str, func_g);
4004 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4006 struct ftrace_page *pg;
4007 struct dyn_ftrace *rec;
4008 struct ftrace_glob func_g = { .type = MATCH_FULL };
4009 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4010 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4011 int exclude_mod = 0;
4014 int clear_filter = 0;
4017 func_g.type = filter_parse_regex(func, len, &func_g.search,
4019 func_g.len = strlen(func_g.search);
4023 mod_g.type = filter_parse_regex(mod, strlen(mod),
4024 &mod_g.search, &exclude_mod);
4025 mod_g.len = strlen(mod_g.search);
4028 mutex_lock(&ftrace_lock);
4030 if (unlikely(ftrace_disabled))
4033 if (func_g.type == MATCH_INDEX) {
4034 found = add_rec_by_index(hash, &func_g, clear_filter);
4038 do_for_each_ftrace_rec(pg, rec) {
4040 if (rec->flags & FTRACE_FL_DISABLED)
4043 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4044 ret = enter_record(hash, rec, clear_filter);
4051 } while_for_each_ftrace_rec();
4053 mutex_unlock(&ftrace_lock);
4059 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4061 return match_records(hash, buff, len, NULL);
4064 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4065 struct ftrace_ops_hash *old_hash)
4067 struct ftrace_ops *op;
4069 if (!ftrace_enabled)
4072 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4073 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4078 * If this is the shared global_ops filter, then we need to
4079 * check if there is another ops that shares it, is enabled.
4080 * If so, we still need to run the modify code.
4082 if (ops->func_hash != &global_ops.local_hash)
4085 do_for_each_ftrace_op(op, ftrace_ops_list) {
4086 if (op->func_hash == &global_ops.local_hash &&
4087 op->flags & FTRACE_OPS_FL_ENABLED) {
4088 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4089 /* Only need to do this once */
4092 } while_for_each_ftrace_op(op);
4095 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4096 struct ftrace_hash **orig_hash,
4097 struct ftrace_hash *hash,
4100 struct ftrace_ops_hash old_hash_ops;
4101 struct ftrace_hash *old_hash;
4104 old_hash = *orig_hash;
4105 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4106 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4107 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4109 ftrace_ops_update_code(ops, &old_hash_ops);
4110 free_ftrace_hash_rcu(old_hash);
4115 static bool module_exists(const char *module)
4117 /* All modules have the symbol __this_module */
4118 static const char this_mod[] = "__this_module";
4119 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4123 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4125 if (n > sizeof(modname) - 1)
4128 val = module_kallsyms_lookup_name(modname);
4132 static int cache_mod(struct trace_array *tr,
4133 const char *func, char *module, int enable)
4135 struct ftrace_mod_load *ftrace_mod, *n;
4136 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4139 mutex_lock(&ftrace_lock);
4141 /* We do not cache inverse filters */
4142 if (func[0] == '!') {
4146 /* Look to remove this hash */
4147 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4148 if (strcmp(ftrace_mod->module, module) != 0)
4151 /* no func matches all */
4152 if (strcmp(func, "*") == 0 ||
4153 (ftrace_mod->func &&
4154 strcmp(ftrace_mod->func, func) == 0)) {
4156 free_ftrace_mod(ftrace_mod);
4164 /* We only care about modules that have not been loaded yet */
4165 if (module_exists(module))
4168 /* Save this string off, and execute it when the module is loaded */
4169 ret = ftrace_add_mod(tr, func, module, enable);
4171 mutex_unlock(&ftrace_lock);
4177 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4178 int reset, int enable);
4180 #ifdef CONFIG_MODULES
4181 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4182 char *mod, bool enable)
4184 struct ftrace_mod_load *ftrace_mod, *n;
4185 struct ftrace_hash **orig_hash, *new_hash;
4186 LIST_HEAD(process_mods);
4189 mutex_lock(&ops->func_hash->regex_lock);
4192 orig_hash = &ops->func_hash->filter_hash;
4194 orig_hash = &ops->func_hash->notrace_hash;
4196 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4199 goto out; /* warn? */
4201 mutex_lock(&ftrace_lock);
4203 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4205 if (strcmp(ftrace_mod->module, mod) != 0)
4208 if (ftrace_mod->func)
4209 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4211 func = kstrdup("*", GFP_KERNEL);
4213 if (!func) /* warn? */
4216 list_del(&ftrace_mod->list);
4217 list_add(&ftrace_mod->list, &process_mods);
4219 /* Use the newly allocated func, as it may be "*" */
4220 kfree(ftrace_mod->func);
4221 ftrace_mod->func = func;
4224 mutex_unlock(&ftrace_lock);
4226 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4228 func = ftrace_mod->func;
4230 /* Grabs ftrace_lock, which is why we have this extra step */
4231 match_records(new_hash, func, strlen(func), mod);
4232 free_ftrace_mod(ftrace_mod);
4235 if (enable && list_empty(head))
4236 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4238 mutex_lock(&ftrace_lock);
4240 ftrace_hash_move_and_update_ops(ops, orig_hash,
4242 mutex_unlock(&ftrace_lock);
4245 mutex_unlock(&ops->func_hash->regex_lock);
4247 free_ftrace_hash(new_hash);
4250 static void process_cached_mods(const char *mod_name)
4252 struct trace_array *tr;
4255 mod = kstrdup(mod_name, GFP_KERNEL);
4259 mutex_lock(&trace_types_lock);
4260 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4261 if (!list_empty(&tr->mod_trace))
4262 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4263 if (!list_empty(&tr->mod_notrace))
4264 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4266 mutex_unlock(&trace_types_lock);
4273 * We register the module command as a template to show others how
4274 * to register the a command as well.
4278 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4279 char *func_orig, char *cmd, char *module, int enable)
4284 /* match_records() modifies func, and we need the original */
4285 func = kstrdup(func_orig, GFP_KERNEL);
4290 * cmd == 'mod' because we only registered this func
4291 * for the 'mod' ftrace_func_command.
4292 * But if you register one func with multiple commands,
4293 * you can tell which command was used by the cmd
4296 ret = match_records(hash, func, strlen(func), module);
4300 return cache_mod(tr, func_orig, module, enable);
4306 static struct ftrace_func_command ftrace_mod_cmd = {
4308 .func = ftrace_mod_callback,
4311 static int __init ftrace_mod_cmd_init(void)
4313 return register_ftrace_command(&ftrace_mod_cmd);
4315 core_initcall(ftrace_mod_cmd_init);
4317 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4318 struct ftrace_ops *op, struct ftrace_regs *fregs)
4320 struct ftrace_probe_ops *probe_ops;
4321 struct ftrace_func_probe *probe;
4323 probe = container_of(op, struct ftrace_func_probe, ops);
4324 probe_ops = probe->probe_ops;
4327 * Disable preemption for these calls to prevent a RCU grace
4328 * period. This syncs the hash iteration and freeing of items
4329 * on the hash. rcu_read_lock is too dangerous here.
4331 preempt_disable_notrace();
4332 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4333 preempt_enable_notrace();
4336 struct ftrace_func_map {
4337 struct ftrace_func_entry entry;
4341 struct ftrace_func_mapper {
4342 struct ftrace_hash hash;
4346 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4348 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4350 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4352 struct ftrace_hash *hash;
4355 * The mapper is simply a ftrace_hash, but since the entries
4356 * in the hash are not ftrace_func_entry type, we define it
4357 * as a separate structure.
4359 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4360 return (struct ftrace_func_mapper *)hash;
4364 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4365 * @mapper: The mapper that has the ip maps
4366 * @ip: the instruction pointer to find the data for
4368 * Returns the data mapped to @ip if found otherwise NULL. The return
4369 * is actually the address of the mapper data pointer. The address is
4370 * returned for use cases where the data is no bigger than a long, and
4371 * the user can use the data pointer as its data instead of having to
4372 * allocate more memory for the reference.
4374 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4377 struct ftrace_func_entry *entry;
4378 struct ftrace_func_map *map;
4380 entry = ftrace_lookup_ip(&mapper->hash, ip);
4384 map = (struct ftrace_func_map *)entry;
4389 * ftrace_func_mapper_add_ip - Map some data to an ip
4390 * @mapper: The mapper that has the ip maps
4391 * @ip: The instruction pointer address to map @data to
4392 * @data: The data to map to @ip
4394 * Returns 0 on success otherwise an error.
4396 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4397 unsigned long ip, void *data)
4399 struct ftrace_func_entry *entry;
4400 struct ftrace_func_map *map;
4402 entry = ftrace_lookup_ip(&mapper->hash, ip);
4406 map = kmalloc(sizeof(*map), GFP_KERNEL);
4413 __add_hash_entry(&mapper->hash, &map->entry);
4419 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4420 * @mapper: The mapper that has the ip maps
4421 * @ip: The instruction pointer address to remove the data from
4423 * Returns the data if it is found, otherwise NULL.
4424 * Note, if the data pointer is used as the data itself, (see
4425 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4426 * if the data pointer was set to zero.
4428 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4431 struct ftrace_func_entry *entry;
4432 struct ftrace_func_map *map;
4435 entry = ftrace_lookup_ip(&mapper->hash, ip);
4439 map = (struct ftrace_func_map *)entry;
4442 remove_hash_entry(&mapper->hash, entry);
4449 * free_ftrace_func_mapper - free a mapping of ips and data
4450 * @mapper: The mapper that has the ip maps
4451 * @free_func: A function to be called on each data item.
4453 * This is used to free the function mapper. The @free_func is optional
4454 * and can be used if the data needs to be freed as well.
4456 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4457 ftrace_mapper_func free_func)
4459 struct ftrace_func_entry *entry;
4460 struct ftrace_func_map *map;
4461 struct hlist_head *hhd;
4467 if (free_func && mapper->hash.count) {
4468 size = 1 << mapper->hash.size_bits;
4469 for (i = 0; i < size; i++) {
4470 hhd = &mapper->hash.buckets[i];
4471 hlist_for_each_entry(entry, hhd, hlist) {
4472 map = (struct ftrace_func_map *)entry;
4477 free_ftrace_hash(&mapper->hash);
4480 static void release_probe(struct ftrace_func_probe *probe)
4482 struct ftrace_probe_ops *probe_ops;
4484 mutex_lock(&ftrace_lock);
4486 WARN_ON(probe->ref <= 0);
4488 /* Subtract the ref that was used to protect this instance */
4492 probe_ops = probe->probe_ops;
4494 * Sending zero as ip tells probe_ops to free
4495 * the probe->data itself
4497 if (probe_ops->free)
4498 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4499 list_del(&probe->list);
4502 mutex_unlock(&ftrace_lock);
4505 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4508 * Add one ref to keep it from being freed when releasing the
4509 * ftrace_lock mutex.
4515 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4516 struct ftrace_probe_ops *probe_ops,
4519 struct ftrace_func_entry *entry;
4520 struct ftrace_func_probe *probe;
4521 struct ftrace_hash **orig_hash;
4522 struct ftrace_hash *old_hash;
4523 struct ftrace_hash *hash;
4532 /* We do not support '!' for function probes */
4533 if (WARN_ON(glob[0] == '!'))
4537 mutex_lock(&ftrace_lock);
4538 /* Check if the probe_ops is already registered */
4539 list_for_each_entry(probe, &tr->func_probes, list) {
4540 if (probe->probe_ops == probe_ops)
4543 if (&probe->list == &tr->func_probes) {
4544 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4546 mutex_unlock(&ftrace_lock);
4549 probe->probe_ops = probe_ops;
4550 probe->ops.func = function_trace_probe_call;
4552 ftrace_ops_init(&probe->ops);
4553 list_add(&probe->list, &tr->func_probes);
4556 acquire_probe_locked(probe);
4558 mutex_unlock(&ftrace_lock);
4561 * Note, there's a small window here that the func_hash->filter_hash
4562 * may be NULL or empty. Need to be careful when reading the loop.
4564 mutex_lock(&probe->ops.func_hash->regex_lock);
4566 orig_hash = &probe->ops.func_hash->filter_hash;
4567 old_hash = *orig_hash;
4568 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4575 ret = ftrace_match_records(hash, glob, strlen(glob));
4577 /* Nothing found? */
4584 size = 1 << hash->size_bits;
4585 for (i = 0; i < size; i++) {
4586 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4587 if (ftrace_lookup_ip(old_hash, entry->ip))
4590 * The caller might want to do something special
4591 * for each function we find. We call the callback
4592 * to give the caller an opportunity to do so.
4594 if (probe_ops->init) {
4595 ret = probe_ops->init(probe_ops, tr,
4599 if (probe_ops->free && count)
4600 probe_ops->free(probe_ops, tr,
4610 mutex_lock(&ftrace_lock);
4613 /* Nothing was added? */
4618 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4623 /* One ref for each new function traced */
4624 probe->ref += count;
4626 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4627 ret = ftrace_startup(&probe->ops, 0);
4630 mutex_unlock(&ftrace_lock);
4635 mutex_unlock(&probe->ops.func_hash->regex_lock);
4636 free_ftrace_hash(hash);
4638 release_probe(probe);
4643 if (!probe_ops->free || !count)
4646 /* Failed to do the move, need to call the free functions */
4647 for (i = 0; i < size; i++) {
4648 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4649 if (ftrace_lookup_ip(old_hash, entry->ip))
4651 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4658 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4659 struct ftrace_probe_ops *probe_ops)
4661 struct ftrace_ops_hash old_hash_ops;
4662 struct ftrace_func_entry *entry;
4663 struct ftrace_func_probe *probe;
4664 struct ftrace_glob func_g;
4665 struct ftrace_hash **orig_hash;
4666 struct ftrace_hash *old_hash;
4667 struct ftrace_hash *hash = NULL;
4668 struct hlist_node *tmp;
4669 struct hlist_head hhd;
4670 char str[KSYM_SYMBOL_LEN];
4672 int i, ret = -ENODEV;
4675 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4676 func_g.search = NULL;
4680 func_g.type = filter_parse_regex(glob, strlen(glob),
4681 &func_g.search, ¬);
4682 func_g.len = strlen(func_g.search);
4684 /* we do not support '!' for function probes */
4689 mutex_lock(&ftrace_lock);
4690 /* Check if the probe_ops is already registered */
4691 list_for_each_entry(probe, &tr->func_probes, list) {
4692 if (probe->probe_ops == probe_ops)
4695 if (&probe->list == &tr->func_probes)
4696 goto err_unlock_ftrace;
4699 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4700 goto err_unlock_ftrace;
4702 acquire_probe_locked(probe);
4704 mutex_unlock(&ftrace_lock);
4706 mutex_lock(&probe->ops.func_hash->regex_lock);
4708 orig_hash = &probe->ops.func_hash->filter_hash;
4709 old_hash = *orig_hash;
4711 if (ftrace_hash_empty(old_hash))
4714 old_hash_ops.filter_hash = old_hash;
4715 /* Probes only have filters */
4716 old_hash_ops.notrace_hash = NULL;
4719 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4723 INIT_HLIST_HEAD(&hhd);
4725 size = 1 << hash->size_bits;
4726 for (i = 0; i < size; i++) {
4727 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4729 if (func_g.search) {
4730 kallsyms_lookup(entry->ip, NULL, NULL,
4732 if (!ftrace_match(str, &func_g))
4736 remove_hash_entry(hash, entry);
4737 hlist_add_head(&entry->hlist, &hhd);
4741 /* Nothing found? */
4747 mutex_lock(&ftrace_lock);
4749 WARN_ON(probe->ref < count);
4751 probe->ref -= count;
4753 if (ftrace_hash_empty(hash))
4754 ftrace_shutdown(&probe->ops, 0);
4756 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4759 /* still need to update the function call sites */
4760 if (ftrace_enabled && !ftrace_hash_empty(hash))
4761 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4765 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4766 hlist_del(&entry->hlist);
4767 if (probe_ops->free)
4768 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4771 mutex_unlock(&ftrace_lock);
4774 mutex_unlock(&probe->ops.func_hash->regex_lock);
4775 free_ftrace_hash(hash);
4777 release_probe(probe);
4782 mutex_unlock(&ftrace_lock);
4786 void clear_ftrace_function_probes(struct trace_array *tr)
4788 struct ftrace_func_probe *probe, *n;
4790 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4791 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4794 static LIST_HEAD(ftrace_commands);
4795 static DEFINE_MUTEX(ftrace_cmd_mutex);
4798 * Currently we only register ftrace commands from __init, so mark this
4801 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4803 struct ftrace_func_command *p;
4806 mutex_lock(&ftrace_cmd_mutex);
4807 list_for_each_entry(p, &ftrace_commands, list) {
4808 if (strcmp(cmd->name, p->name) == 0) {
4813 list_add(&cmd->list, &ftrace_commands);
4815 mutex_unlock(&ftrace_cmd_mutex);
4821 * Currently we only unregister ftrace commands from __init, so mark
4824 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4826 struct ftrace_func_command *p, *n;
4829 mutex_lock(&ftrace_cmd_mutex);
4830 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4831 if (strcmp(cmd->name, p->name) == 0) {
4833 list_del_init(&p->list);
4838 mutex_unlock(&ftrace_cmd_mutex);
4843 static int ftrace_process_regex(struct ftrace_iterator *iter,
4844 char *buff, int len, int enable)
4846 struct ftrace_hash *hash = iter->hash;
4847 struct trace_array *tr = iter->ops->private;
4848 char *func, *command, *next = buff;
4849 struct ftrace_func_command *p;
4852 func = strsep(&next, ":");
4855 ret = ftrace_match_records(hash, func, len);
4865 command = strsep(&next, ":");
4867 mutex_lock(&ftrace_cmd_mutex);
4868 list_for_each_entry(p, &ftrace_commands, list) {
4869 if (strcmp(p->name, command) == 0) {
4870 ret = p->func(tr, hash, func, command, next, enable);
4875 mutex_unlock(&ftrace_cmd_mutex);
4881 ftrace_regex_write(struct file *file, const char __user *ubuf,
4882 size_t cnt, loff_t *ppos, int enable)
4884 struct ftrace_iterator *iter;
4885 struct trace_parser *parser;
4891 if (file->f_mode & FMODE_READ) {
4892 struct seq_file *m = file->private_data;
4895 iter = file->private_data;
4897 if (unlikely(ftrace_disabled))
4900 /* iter->hash is a local copy, so we don't need regex_lock */
4902 parser = &iter->parser;
4903 read = trace_get_user(parser, ubuf, cnt, ppos);
4905 if (read >= 0 && trace_parser_loaded(parser) &&
4906 !trace_parser_cont(parser)) {
4907 ret = ftrace_process_regex(iter, parser->buffer,
4908 parser->idx, enable);
4909 trace_parser_clear(parser);
4920 ftrace_filter_write(struct file *file, const char __user *ubuf,
4921 size_t cnt, loff_t *ppos)
4923 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4927 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4928 size_t cnt, loff_t *ppos)
4930 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4934 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4936 struct ftrace_func_entry *entry;
4938 if (!ftrace_location(ip))
4942 entry = ftrace_lookup_ip(hash, ip);
4945 free_hash_entry(hash, entry);
4949 return add_hash_entry(hash, ip);
4953 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4954 unsigned long ip, int remove, int reset, int enable)
4956 struct ftrace_hash **orig_hash;
4957 struct ftrace_hash *hash;
4960 if (unlikely(ftrace_disabled))
4963 mutex_lock(&ops->func_hash->regex_lock);
4966 orig_hash = &ops->func_hash->filter_hash;
4968 orig_hash = &ops->func_hash->notrace_hash;
4971 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4973 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4977 goto out_regex_unlock;
4980 if (buf && !ftrace_match_records(hash, buf, len)) {
4982 goto out_regex_unlock;
4985 ret = ftrace_match_addr(hash, ip, remove);
4987 goto out_regex_unlock;
4990 mutex_lock(&ftrace_lock);
4991 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4992 mutex_unlock(&ftrace_lock);
4995 mutex_unlock(&ops->func_hash->regex_lock);
4997 free_ftrace_hash(hash);
5002 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
5003 int reset, int enable)
5005 return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
5008 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5010 struct ftrace_direct_func {
5011 struct list_head next;
5016 static LIST_HEAD(ftrace_direct_funcs);
5019 * ftrace_find_direct_func - test an address if it is a registered direct caller
5020 * @addr: The address of a registered direct caller
5022 * This searches to see if a ftrace direct caller has been registered
5023 * at a specific address, and if so, it returns a descriptor for it.
5025 * This can be used by architecture code to see if an address is
5026 * a direct caller (trampoline) attached to a fentry/mcount location.
5027 * This is useful for the function_graph tracer, as it may need to
5028 * do adjustments if it traced a location that also has a direct
5029 * trampoline attached to it.
5031 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5033 struct ftrace_direct_func *entry;
5036 /* May be called by fgraph trampoline (protected by rcu tasks) */
5037 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5038 if (entry->addr == addr) {
5049 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5051 struct ftrace_direct_func *direct;
5053 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5056 direct->addr = addr;
5058 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5059 ftrace_direct_func_count++;
5064 * register_ftrace_direct - Call a custom trampoline directly
5065 * @ip: The address of the nop at the beginning of a function
5066 * @addr: The address of the trampoline to call at @ip
5068 * This is used to connect a direct call from the nop location (@ip)
5069 * at the start of ftrace traced functions. The location that it calls
5070 * (@addr) must be able to handle a direct call, and save the parameters
5071 * of the function being traced, and restore them (or inject new ones
5072 * if needed), before returning.
5076 * -EBUSY - Another direct function is already attached (there can be only one)
5077 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5078 * -ENOMEM - There was an allocation failure.
5080 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5082 struct ftrace_direct_func *direct;
5083 struct ftrace_func_entry *entry;
5084 struct ftrace_hash *free_hash = NULL;
5085 struct dyn_ftrace *rec;
5088 mutex_lock(&direct_mutex);
5090 /* See if there's a direct function at @ip already */
5091 if (ftrace_find_rec_direct(ip))
5095 rec = lookup_rec(ip, ip);
5100 * Check if the rec says it has a direct call but we didn't
5103 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5106 /* Make sure the ip points to the exact record */
5107 if (ip != rec->ip) {
5109 /* Need to check this ip for a direct. */
5110 if (ftrace_find_rec_direct(ip))
5115 if (ftrace_hash_empty(direct_functions) ||
5116 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
5117 struct ftrace_hash *new_hash;
5118 int size = ftrace_hash_empty(direct_functions) ? 0 :
5119 direct_functions->count + 1;
5124 new_hash = dup_hash(direct_functions, size);
5128 free_hash = direct_functions;
5129 direct_functions = new_hash;
5132 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
5136 direct = ftrace_find_direct_func(addr);
5138 direct = ftrace_alloc_direct_func(addr);
5146 entry->direct = addr;
5147 __add_hash_entry(direct_functions, entry);
5149 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5151 remove_hash_entry(direct_functions, entry);
5153 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5154 ret = register_ftrace_function(&direct_ops);
5156 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5161 if (!direct->count) {
5162 list_del_rcu(&direct->next);
5163 synchronize_rcu_tasks();
5166 free_ftrace_hash(free_hash);
5168 ftrace_direct_func_count--;
5174 mutex_unlock(&direct_mutex);
5177 synchronize_rcu_tasks();
5178 free_ftrace_hash(free_hash);
5183 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5185 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5186 struct dyn_ftrace **recp)
5188 struct ftrace_func_entry *entry;
5189 struct dyn_ftrace *rec;
5191 rec = lookup_rec(*ip, *ip);
5195 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5197 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5201 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5203 /* Passed in ip just needs to be on the call site */
5212 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5214 struct ftrace_direct_func *direct;
5215 struct ftrace_func_entry *entry;
5218 mutex_lock(&direct_mutex);
5220 entry = find_direct_entry(&ip, NULL);
5224 if (direct_functions->count == 1)
5225 unregister_ftrace_function(&direct_ops);
5227 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5231 remove_hash_entry(direct_functions, entry);
5233 direct = ftrace_find_direct_func(addr);
5234 if (!WARN_ON(!direct)) {
5235 /* This is the good path (see the ! before WARN) */
5237 WARN_ON(direct->count < 0);
5238 if (!direct->count) {
5239 list_del_rcu(&direct->next);
5240 synchronize_rcu_tasks();
5243 ftrace_direct_func_count--;
5247 mutex_unlock(&direct_mutex);
5251 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5253 static struct ftrace_ops stub_ops = {
5254 .func = ftrace_stub,
5258 * ftrace_modify_direct_caller - modify ftrace nop directly
5259 * @entry: The ftrace hash entry of the direct helper for @rec
5260 * @rec: The record representing the function site to patch
5261 * @old_addr: The location that the site at @rec->ip currently calls
5262 * @new_addr: The location that the site at @rec->ip should call
5264 * An architecture may overwrite this function to optimize the
5265 * changing of the direct callback on an ftrace nop location.
5266 * This is called with the ftrace_lock mutex held, and no other
5267 * ftrace callbacks are on the associated record (@rec). Thus,
5268 * it is safe to modify the ftrace record, where it should be
5269 * currently calling @old_addr directly, to call @new_addr.
5271 * Safety checks should be made to make sure that the code at
5272 * @rec->ip is currently calling @old_addr. And this must
5273 * also update entry->direct to @new_addr.
5275 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5276 struct dyn_ftrace *rec,
5277 unsigned long old_addr,
5278 unsigned long new_addr)
5280 unsigned long ip = rec->ip;
5284 * The ftrace_lock was used to determine if the record
5285 * had more than one registered user to it. If it did,
5286 * we needed to prevent that from changing to do the quick
5287 * switch. But if it did not (only a direct caller was attached)
5288 * then this function is called. But this function can deal
5289 * with attached callers to the rec that we care about, and
5290 * since this function uses standard ftrace calls that take
5291 * the ftrace_lock mutex, we need to release it.
5293 mutex_unlock(&ftrace_lock);
5296 * By setting a stub function at the same address, we force
5297 * the code to call the iterator and the direct_ops helper.
5298 * This means that @ip does not call the direct call, and
5299 * we can simply modify it.
5301 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5305 ret = register_ftrace_function(&stub_ops);
5307 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5311 entry->direct = new_addr;
5314 * By removing the stub, we put back the direct call, calling
5317 unregister_ftrace_function(&stub_ops);
5318 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5321 mutex_lock(&ftrace_lock);
5327 * modify_ftrace_direct - Modify an existing direct call to call something else
5328 * @ip: The instruction pointer to modify
5329 * @old_addr: The address that the current @ip calls directly
5330 * @new_addr: The address that the @ip should call
5332 * This modifies a ftrace direct caller at an instruction pointer without
5333 * having to disable it first. The direct call will switch over to the
5334 * @new_addr without missing anything.
5336 * Returns: zero on success. Non zero on error, which includes:
5337 * -ENODEV : the @ip given has no direct caller attached
5338 * -EINVAL : the @old_addr does not match the current direct caller
5340 int modify_ftrace_direct(unsigned long ip,
5341 unsigned long old_addr, unsigned long new_addr)
5343 struct ftrace_direct_func *direct, *new_direct = NULL;
5344 struct ftrace_func_entry *entry;
5345 struct dyn_ftrace *rec;
5348 mutex_lock(&direct_mutex);
5350 mutex_lock(&ftrace_lock);
5351 entry = find_direct_entry(&ip, &rec);
5356 if (entry->direct != old_addr)
5359 direct = ftrace_find_direct_func(old_addr);
5360 if (WARN_ON(!direct))
5362 if (direct->count > 1) {
5364 new_direct = ftrace_alloc_direct_func(new_addr);
5368 new_direct->count++;
5370 direct->addr = new_addr;
5374 * If there's no other ftrace callback on the rec->ip location,
5375 * then it can be changed directly by the architecture.
5376 * If there is another caller, then we just need to change the
5377 * direct caller helper to point to @new_addr.
5379 if (ftrace_rec_count(rec) == 1) {
5380 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5382 entry->direct = new_addr;
5386 if (unlikely(ret && new_direct)) {
5388 list_del_rcu(&new_direct->next);
5389 synchronize_rcu_tasks();
5391 ftrace_direct_func_count--;
5395 mutex_unlock(&ftrace_lock);
5396 mutex_unlock(&direct_mutex);
5399 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5400 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5403 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5404 * @ops - the ops to set the filter with
5405 * @ip - the address to add to or remove from the filter.
5406 * @remove - non zero to remove the ip from the filter
5407 * @reset - non zero to reset all filters before applying this filter.
5409 * Filters denote which functions should be enabled when tracing is enabled
5410 * If @ip is NULL, it failes to update filter.
5412 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5413 int remove, int reset)
5415 ftrace_ops_init(ops);
5416 return ftrace_set_addr(ops, ip, remove, reset, 1);
5418 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5421 * ftrace_ops_set_global_filter - setup ops to use global filters
5422 * @ops - the ops which will use the global filters
5424 * ftrace users who need global function trace filtering should call this.
5425 * It can set the global filter only if ops were not initialized before.
5427 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5429 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5432 ftrace_ops_init(ops);
5433 ops->func_hash = &global_ops.local_hash;
5435 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5438 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5439 int reset, int enable)
5441 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
5445 * ftrace_set_filter - set a function to filter on in ftrace
5446 * @ops - the ops to set the filter with
5447 * @buf - the string that holds the function filter text.
5448 * @len - the length of the string.
5449 * @reset - non zero to reset all filters before applying this filter.
5451 * Filters denote which functions should be enabled when tracing is enabled.
5452 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5454 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5457 ftrace_ops_init(ops);
5458 return ftrace_set_regex(ops, buf, len, reset, 1);
5460 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5463 * ftrace_set_notrace - set a function to not trace in ftrace
5464 * @ops - the ops to set the notrace filter with
5465 * @buf - the string that holds the function notrace text.
5466 * @len - the length of the string.
5467 * @reset - non zero to reset all filters before applying this filter.
5469 * Notrace Filters denote which functions should not be enabled when tracing
5470 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5473 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5476 ftrace_ops_init(ops);
5477 return ftrace_set_regex(ops, buf, len, reset, 0);
5479 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5481 * ftrace_set_global_filter - set a function to filter on with global tracers
5482 * @buf - the string that holds the function filter text.
5483 * @len - the length of the string.
5484 * @reset - non zero to reset all filters before applying this filter.
5486 * Filters denote which functions should be enabled when tracing is enabled.
5487 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5489 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5491 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5493 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5496 * ftrace_set_global_notrace - set a function to not trace with global tracers
5497 * @buf - the string that holds the function notrace text.
5498 * @len - the length of the string.
5499 * @reset - non zero to reset all filters before applying this filter.
5501 * Notrace Filters denote which functions should not be enabled when tracing
5502 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5505 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5507 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5509 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5512 * command line interface to allow users to set filters on boot up.
5514 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5515 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5516 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5518 /* Used by function selftest to not test if filter is set */
5519 bool ftrace_filter_param __initdata;
5521 static int __init set_ftrace_notrace(char *str)
5523 ftrace_filter_param = true;
5524 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5527 __setup("ftrace_notrace=", set_ftrace_notrace);
5529 static int __init set_ftrace_filter(char *str)
5531 ftrace_filter_param = true;
5532 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5535 __setup("ftrace_filter=", set_ftrace_filter);
5537 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5538 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5539 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5540 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5542 static int __init set_graph_function(char *str)
5544 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5547 __setup("ftrace_graph_filter=", set_graph_function);
5549 static int __init set_graph_notrace_function(char *str)
5551 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5554 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5556 static int __init set_graph_max_depth_function(char *str)
5560 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5563 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5565 static void __init set_ftrace_early_graph(char *buf, int enable)
5569 struct ftrace_hash *hash;
5571 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5572 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5576 func = strsep(&buf, ",");
5577 /* we allow only one expression at a time */
5578 ret = ftrace_graph_set_hash(hash, func);
5580 printk(KERN_DEBUG "ftrace: function %s not "
5581 "traceable\n", func);
5585 ftrace_graph_hash = hash;
5587 ftrace_graph_notrace_hash = hash;
5589 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5592 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5596 ftrace_ops_init(ops);
5599 func = strsep(&buf, ",");
5600 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5604 static void __init set_ftrace_early_filters(void)
5606 if (ftrace_filter_buf[0])
5607 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5608 if (ftrace_notrace_buf[0])
5609 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5610 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5611 if (ftrace_graph_buf[0])
5612 set_ftrace_early_graph(ftrace_graph_buf, 1);
5613 if (ftrace_graph_notrace_buf[0])
5614 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5615 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5618 int ftrace_regex_release(struct inode *inode, struct file *file)
5620 struct seq_file *m = (struct seq_file *)file->private_data;
5621 struct ftrace_iterator *iter;
5622 struct ftrace_hash **orig_hash;
5623 struct trace_parser *parser;
5626 if (file->f_mode & FMODE_READ) {
5628 seq_release(inode, file);
5630 iter = file->private_data;
5632 parser = &iter->parser;
5633 if (trace_parser_loaded(parser)) {
5634 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5637 trace_parser_put(parser);
5639 mutex_lock(&iter->ops->func_hash->regex_lock);
5641 if (file->f_mode & FMODE_WRITE) {
5642 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5645 orig_hash = &iter->ops->func_hash->filter_hash;
5646 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5647 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5649 orig_hash = &iter->ops->func_hash->notrace_hash;
5651 mutex_lock(&ftrace_lock);
5652 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5653 iter->hash, filter_hash);
5654 mutex_unlock(&ftrace_lock);
5656 /* For read only, the hash is the ops hash */
5660 mutex_unlock(&iter->ops->func_hash->regex_lock);
5661 free_ftrace_hash(iter->hash);
5663 trace_array_put(iter->tr);
5669 static const struct file_operations ftrace_avail_fops = {
5670 .open = ftrace_avail_open,
5672 .llseek = seq_lseek,
5673 .release = seq_release_private,
5676 static const struct file_operations ftrace_enabled_fops = {
5677 .open = ftrace_enabled_open,
5679 .llseek = seq_lseek,
5680 .release = seq_release_private,
5683 static const struct file_operations ftrace_filter_fops = {
5684 .open = ftrace_filter_open,
5686 .write = ftrace_filter_write,
5687 .llseek = tracing_lseek,
5688 .release = ftrace_regex_release,
5691 static const struct file_operations ftrace_notrace_fops = {
5692 .open = ftrace_notrace_open,
5694 .write = ftrace_notrace_write,
5695 .llseek = tracing_lseek,
5696 .release = ftrace_regex_release,
5699 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5701 static DEFINE_MUTEX(graph_lock);
5703 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5704 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5706 enum graph_filter_type {
5707 GRAPH_FILTER_NOTRACE = 0,
5708 GRAPH_FILTER_FUNCTION,
5711 #define FTRACE_GRAPH_EMPTY ((void *)1)
5713 struct ftrace_graph_data {
5714 struct ftrace_hash *hash;
5715 struct ftrace_func_entry *entry;
5716 int idx; /* for hash table iteration */
5717 enum graph_filter_type type;
5718 struct ftrace_hash *new_hash;
5719 const struct seq_operations *seq_ops;
5720 struct trace_parser parser;
5724 __g_next(struct seq_file *m, loff_t *pos)
5726 struct ftrace_graph_data *fgd = m->private;
5727 struct ftrace_func_entry *entry = fgd->entry;
5728 struct hlist_head *head;
5729 int i, idx = fgd->idx;
5731 if (*pos >= fgd->hash->count)
5735 hlist_for_each_entry_continue(entry, hlist) {
5743 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5744 head = &fgd->hash->buckets[i];
5745 hlist_for_each_entry(entry, head, hlist) {
5755 g_next(struct seq_file *m, void *v, loff_t *pos)
5758 return __g_next(m, pos);
5761 static void *g_start(struct seq_file *m, loff_t *pos)
5763 struct ftrace_graph_data *fgd = m->private;
5765 mutex_lock(&graph_lock);
5767 if (fgd->type == GRAPH_FILTER_FUNCTION)
5768 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5769 lockdep_is_held(&graph_lock));
5771 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5772 lockdep_is_held(&graph_lock));
5774 /* Nothing, tell g_show to print all functions are enabled */
5775 if (ftrace_hash_empty(fgd->hash) && !*pos)
5776 return FTRACE_GRAPH_EMPTY;
5780 return __g_next(m, pos);
5783 static void g_stop(struct seq_file *m, void *p)
5785 mutex_unlock(&graph_lock);
5788 static int g_show(struct seq_file *m, void *v)
5790 struct ftrace_func_entry *entry = v;
5795 if (entry == FTRACE_GRAPH_EMPTY) {
5796 struct ftrace_graph_data *fgd = m->private;
5798 if (fgd->type == GRAPH_FILTER_FUNCTION)
5799 seq_puts(m, "#### all functions enabled ####\n");
5801 seq_puts(m, "#### no functions disabled ####\n");
5805 seq_printf(m, "%ps\n", (void *)entry->ip);
5810 static const struct seq_operations ftrace_graph_seq_ops = {
5818 __ftrace_graph_open(struct inode *inode, struct file *file,
5819 struct ftrace_graph_data *fgd)
5822 struct ftrace_hash *new_hash = NULL;
5824 ret = security_locked_down(LOCKDOWN_TRACEFS);
5828 if (file->f_mode & FMODE_WRITE) {
5829 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5831 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5834 if (file->f_flags & O_TRUNC)
5835 new_hash = alloc_ftrace_hash(size_bits);
5837 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5845 if (file->f_mode & FMODE_READ) {
5846 ret = seq_open(file, &ftrace_graph_seq_ops);
5848 struct seq_file *m = file->private_data;
5852 free_ftrace_hash(new_hash);
5856 file->private_data = fgd;
5859 if (ret < 0 && file->f_mode & FMODE_WRITE)
5860 trace_parser_put(&fgd->parser);
5862 fgd->new_hash = new_hash;
5865 * All uses of fgd->hash must be taken with the graph_lock
5866 * held. The graph_lock is going to be released, so force
5867 * fgd->hash to be reinitialized when it is taken again.
5875 ftrace_graph_open(struct inode *inode, struct file *file)
5877 struct ftrace_graph_data *fgd;
5880 if (unlikely(ftrace_disabled))
5883 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5887 mutex_lock(&graph_lock);
5889 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5890 lockdep_is_held(&graph_lock));
5891 fgd->type = GRAPH_FILTER_FUNCTION;
5892 fgd->seq_ops = &ftrace_graph_seq_ops;
5894 ret = __ftrace_graph_open(inode, file, fgd);
5898 mutex_unlock(&graph_lock);
5903 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5905 struct ftrace_graph_data *fgd;
5908 if (unlikely(ftrace_disabled))
5911 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5915 mutex_lock(&graph_lock);
5917 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5918 lockdep_is_held(&graph_lock));
5919 fgd->type = GRAPH_FILTER_NOTRACE;
5920 fgd->seq_ops = &ftrace_graph_seq_ops;
5922 ret = __ftrace_graph_open(inode, file, fgd);
5926 mutex_unlock(&graph_lock);
5931 ftrace_graph_release(struct inode *inode, struct file *file)
5933 struct ftrace_graph_data *fgd;
5934 struct ftrace_hash *old_hash, *new_hash;
5935 struct trace_parser *parser;
5938 if (file->f_mode & FMODE_READ) {
5939 struct seq_file *m = file->private_data;
5942 seq_release(inode, file);
5944 fgd = file->private_data;
5948 if (file->f_mode & FMODE_WRITE) {
5950 parser = &fgd->parser;
5952 if (trace_parser_loaded((parser))) {
5953 ret = ftrace_graph_set_hash(fgd->new_hash,
5957 trace_parser_put(parser);
5959 new_hash = __ftrace_hash_move(fgd->new_hash);
5965 mutex_lock(&graph_lock);
5967 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5968 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5969 lockdep_is_held(&graph_lock));
5970 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5972 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5973 lockdep_is_held(&graph_lock));
5974 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5977 mutex_unlock(&graph_lock);
5980 * We need to do a hard force of sched synchronization.
5981 * This is because we use preempt_disable() to do RCU, but
5982 * the function tracers can be called where RCU is not watching
5983 * (like before user_exit()). We can not rely on the RCU
5984 * infrastructure to do the synchronization, thus we must do it
5987 synchronize_rcu_tasks_rude();
5989 free_ftrace_hash(old_hash);
5993 free_ftrace_hash(fgd->new_hash);
6000 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6002 struct ftrace_glob func_g;
6003 struct dyn_ftrace *rec;
6004 struct ftrace_page *pg;
6005 struct ftrace_func_entry *entry;
6010 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6011 &func_g.search, ¬);
6013 func_g.len = strlen(func_g.search);
6015 mutex_lock(&ftrace_lock);
6017 if (unlikely(ftrace_disabled)) {
6018 mutex_unlock(&ftrace_lock);
6022 do_for_each_ftrace_rec(pg, rec) {
6024 if (rec->flags & FTRACE_FL_DISABLED)
6027 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6028 entry = ftrace_lookup_ip(hash, rec->ip);
6035 if (add_hash_entry(hash, rec->ip) < 0)
6039 free_hash_entry(hash, entry);
6044 } while_for_each_ftrace_rec();
6046 mutex_unlock(&ftrace_lock);
6055 ftrace_graph_write(struct file *file, const char __user *ubuf,
6056 size_t cnt, loff_t *ppos)
6058 ssize_t read, ret = 0;
6059 struct ftrace_graph_data *fgd = file->private_data;
6060 struct trace_parser *parser;
6065 /* Read mode uses seq functions */
6066 if (file->f_mode & FMODE_READ) {
6067 struct seq_file *m = file->private_data;
6071 parser = &fgd->parser;
6073 read = trace_get_user(parser, ubuf, cnt, ppos);
6075 if (read >= 0 && trace_parser_loaded(parser) &&
6076 !trace_parser_cont(parser)) {
6078 ret = ftrace_graph_set_hash(fgd->new_hash,
6080 trace_parser_clear(parser);
6089 static const struct file_operations ftrace_graph_fops = {
6090 .open = ftrace_graph_open,
6092 .write = ftrace_graph_write,
6093 .llseek = tracing_lseek,
6094 .release = ftrace_graph_release,
6097 static const struct file_operations ftrace_graph_notrace_fops = {
6098 .open = ftrace_graph_notrace_open,
6100 .write = ftrace_graph_write,
6101 .llseek = tracing_lseek,
6102 .release = ftrace_graph_release,
6104 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6106 void ftrace_create_filter_files(struct ftrace_ops *ops,
6107 struct dentry *parent)
6110 trace_create_file("set_ftrace_filter", 0644, parent,
6111 ops, &ftrace_filter_fops);
6113 trace_create_file("set_ftrace_notrace", 0644, parent,
6114 ops, &ftrace_notrace_fops);
6118 * The name "destroy_filter_files" is really a misnomer. Although
6119 * in the future, it may actually delete the files, but this is
6120 * really intended to make sure the ops passed in are disabled
6121 * and that when this function returns, the caller is free to
6124 * The "destroy" name is only to match the "create" name that this
6125 * should be paired with.
6127 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6129 mutex_lock(&ftrace_lock);
6130 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6131 ftrace_shutdown(ops, 0);
6132 ops->flags |= FTRACE_OPS_FL_DELETED;
6133 ftrace_free_filter(ops);
6134 mutex_unlock(&ftrace_lock);
6137 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6140 trace_create_file("available_filter_functions", 0444,
6141 d_tracer, NULL, &ftrace_avail_fops);
6143 trace_create_file("enabled_functions", 0444,
6144 d_tracer, NULL, &ftrace_enabled_fops);
6146 ftrace_create_filter_files(&global_ops, d_tracer);
6148 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6149 trace_create_file("set_graph_function", 0644, d_tracer,
6151 &ftrace_graph_fops);
6152 trace_create_file("set_graph_notrace", 0644, d_tracer,
6154 &ftrace_graph_notrace_fops);
6155 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6160 static int ftrace_cmp_ips(const void *a, const void *b)
6162 const unsigned long *ipa = a;
6163 const unsigned long *ipb = b;
6172 static int ftrace_process_locs(struct module *mod,
6173 unsigned long *start,
6176 struct ftrace_page *start_pg;
6177 struct ftrace_page *pg;
6178 struct dyn_ftrace *rec;
6179 unsigned long count;
6182 unsigned long flags = 0; /* Shut up gcc */
6185 count = end - start;
6190 sort(start, count, sizeof(*start),
6191 ftrace_cmp_ips, NULL);
6193 start_pg = ftrace_allocate_pages(count);
6197 mutex_lock(&ftrace_lock);
6200 * Core and each module needs their own pages, as
6201 * modules will free them when they are removed.
6202 * Force a new page to be allocated for modules.
6205 WARN_ON(ftrace_pages || ftrace_pages_start);
6206 /* First initialization */
6207 ftrace_pages = ftrace_pages_start = start_pg;
6212 if (WARN_ON(ftrace_pages->next)) {
6213 /* Hmm, we have free pages? */
6214 while (ftrace_pages->next)
6215 ftrace_pages = ftrace_pages->next;
6218 ftrace_pages->next = start_pg;
6224 addr = ftrace_call_adjust(*p++);
6226 * Some architecture linkers will pad between
6227 * the different mcount_loc sections of different
6228 * object files to satisfy alignments.
6229 * Skip any NULL pointers.
6234 if (pg->index == pg->size) {
6235 /* We should have allocated enough */
6236 if (WARN_ON(!pg->next))
6241 rec = &pg->records[pg->index++];
6245 /* We should have used all pages */
6248 /* Assign the last page to ftrace_pages */
6252 * We only need to disable interrupts on start up
6253 * because we are modifying code that an interrupt
6254 * may execute, and the modification is not atomic.
6255 * But for modules, nothing runs the code we modify
6256 * until we are finished with it, and there's no
6257 * reason to cause large interrupt latencies while we do it.
6260 local_irq_save(flags);
6261 ftrace_update_code(mod, start_pg);
6263 local_irq_restore(flags);
6266 mutex_unlock(&ftrace_lock);
6271 struct ftrace_mod_func {
6272 struct list_head list;
6278 struct ftrace_mod_map {
6279 struct rcu_head rcu;
6280 struct list_head list;
6282 unsigned long start_addr;
6283 unsigned long end_addr;
6284 struct list_head funcs;
6285 unsigned int num_funcs;
6288 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6289 unsigned long *value, char *type,
6290 char *name, char *module_name,
6293 struct ftrace_ops *op;
6295 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6296 if (!op->trampoline || symnum--)
6298 *value = op->trampoline;
6300 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6301 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6309 #ifdef CONFIG_MODULES
6311 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6313 static LIST_HEAD(ftrace_mod_maps);
6315 static int referenced_filters(struct dyn_ftrace *rec)
6317 struct ftrace_ops *ops;
6320 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6321 if (ops_references_rec(ops, rec)) {
6322 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6324 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6327 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6328 rec->flags |= FTRACE_FL_REGS;
6329 if (cnt == 1 && ops->trampoline)
6330 rec->flags |= FTRACE_FL_TRAMP;
6332 rec->flags &= ~FTRACE_FL_TRAMP;
6340 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6342 struct ftrace_func_entry *entry;
6343 struct dyn_ftrace *rec;
6346 if (ftrace_hash_empty(hash))
6349 for (i = 0; i < pg->index; i++) {
6350 rec = &pg->records[i];
6351 entry = __ftrace_lookup_ip(hash, rec->ip);
6353 * Do not allow this rec to match again.
6354 * Yeah, it may waste some memory, but will be removed
6355 * if/when the hash is modified again.
6362 /* Clear any records from hashs */
6363 static void clear_mod_from_hashes(struct ftrace_page *pg)
6365 struct trace_array *tr;
6367 mutex_lock(&trace_types_lock);
6368 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6369 if (!tr->ops || !tr->ops->func_hash)
6371 mutex_lock(&tr->ops->func_hash->regex_lock);
6372 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6373 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6374 mutex_unlock(&tr->ops->func_hash->regex_lock);
6376 mutex_unlock(&trace_types_lock);
6379 static void ftrace_free_mod_map(struct rcu_head *rcu)
6381 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6382 struct ftrace_mod_func *mod_func;
6383 struct ftrace_mod_func *n;
6385 /* All the contents of mod_map are now not visible to readers */
6386 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6387 kfree(mod_func->name);
6388 list_del(&mod_func->list);
6395 void ftrace_release_mod(struct module *mod)
6397 struct ftrace_mod_map *mod_map;
6398 struct ftrace_mod_map *n;
6399 struct dyn_ftrace *rec;
6400 struct ftrace_page **last_pg;
6401 struct ftrace_page *tmp_page = NULL;
6402 struct ftrace_page *pg;
6405 mutex_lock(&ftrace_lock);
6407 if (ftrace_disabled)
6410 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6411 if (mod_map->mod == mod) {
6412 list_del_rcu(&mod_map->list);
6413 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6419 * Each module has its own ftrace_pages, remove
6420 * them from the list.
6422 last_pg = &ftrace_pages_start;
6423 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6424 rec = &pg->records[0];
6425 if (within_module_core(rec->ip, mod) ||
6426 within_module_init(rec->ip, mod)) {
6428 * As core pages are first, the first
6429 * page should never be a module page.
6431 if (WARN_ON(pg == ftrace_pages_start))
6434 /* Check if we are deleting the last page */
6435 if (pg == ftrace_pages)
6436 ftrace_pages = next_to_ftrace_page(last_pg);
6438 ftrace_update_tot_cnt -= pg->index;
6439 *last_pg = pg->next;
6441 pg->next = tmp_page;
6444 last_pg = &pg->next;
6447 mutex_unlock(&ftrace_lock);
6449 for (pg = tmp_page; pg; pg = tmp_page) {
6451 /* Needs to be called outside of ftrace_lock */
6452 clear_mod_from_hashes(pg);
6454 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6456 free_pages((unsigned long)pg->records, order);
6457 tmp_page = pg->next;
6459 ftrace_number_of_pages -= 1 << order;
6460 ftrace_number_of_groups--;
6464 void ftrace_module_enable(struct module *mod)
6466 struct dyn_ftrace *rec;
6467 struct ftrace_page *pg;
6469 mutex_lock(&ftrace_lock);
6471 if (ftrace_disabled)
6475 * If the tracing is enabled, go ahead and enable the record.
6477 * The reason not to enable the record immediately is the
6478 * inherent check of ftrace_make_nop/ftrace_make_call for
6479 * correct previous instructions. Making first the NOP
6480 * conversion puts the module to the correct state, thus
6481 * passing the ftrace_make_call check.
6483 * We also delay this to after the module code already set the
6484 * text to read-only, as we now need to set it back to read-write
6485 * so that we can modify the text.
6487 if (ftrace_start_up)
6488 ftrace_arch_code_modify_prepare();
6490 do_for_each_ftrace_rec(pg, rec) {
6493 * do_for_each_ftrace_rec() is a double loop.
6494 * module text shares the pg. If a record is
6495 * not part of this module, then skip this pg,
6496 * which the "break" will do.
6498 if (!within_module_core(rec->ip, mod) &&
6499 !within_module_init(rec->ip, mod))
6505 * When adding a module, we need to check if tracers are
6506 * currently enabled and if they are, and can trace this record,
6507 * we need to enable the module functions as well as update the
6508 * reference counts for those function records.
6510 if (ftrace_start_up)
6511 cnt += referenced_filters(rec);
6513 rec->flags &= ~FTRACE_FL_DISABLED;
6516 if (ftrace_start_up && cnt) {
6517 int failed = __ftrace_replace_code(rec, 1);
6519 ftrace_bug(failed, rec);
6524 } while_for_each_ftrace_rec();
6527 if (ftrace_start_up)
6528 ftrace_arch_code_modify_post_process();
6531 mutex_unlock(&ftrace_lock);
6533 process_cached_mods(mod->name);
6536 void ftrace_module_init(struct module *mod)
6538 if (ftrace_disabled || !mod->num_ftrace_callsites)
6541 ftrace_process_locs(mod, mod->ftrace_callsites,
6542 mod->ftrace_callsites + mod->num_ftrace_callsites);
6545 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6546 struct dyn_ftrace *rec)
6548 struct ftrace_mod_func *mod_func;
6549 unsigned long symsize;
6550 unsigned long offset;
6551 char str[KSYM_SYMBOL_LEN];
6555 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6559 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6563 mod_func->name = kstrdup(str, GFP_KERNEL);
6564 if (!mod_func->name) {
6569 mod_func->ip = rec->ip - offset;
6570 mod_func->size = symsize;
6572 mod_map->num_funcs++;
6574 list_add_rcu(&mod_func->list, &mod_map->funcs);
6577 static struct ftrace_mod_map *
6578 allocate_ftrace_mod_map(struct module *mod,
6579 unsigned long start, unsigned long end)
6581 struct ftrace_mod_map *mod_map;
6583 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6588 mod_map->start_addr = start;
6589 mod_map->end_addr = end;
6590 mod_map->num_funcs = 0;
6592 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6594 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6600 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6601 unsigned long addr, unsigned long *size,
6602 unsigned long *off, char *sym)
6604 struct ftrace_mod_func *found_func = NULL;
6605 struct ftrace_mod_func *mod_func;
6607 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6608 if (addr >= mod_func->ip &&
6609 addr < mod_func->ip + mod_func->size) {
6610 found_func = mod_func;
6617 *size = found_func->size;
6619 *off = addr - found_func->ip;
6621 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6623 return found_func->name;
6630 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6631 unsigned long *off, char **modname, char *sym)
6633 struct ftrace_mod_map *mod_map;
6634 const char *ret = NULL;
6636 /* mod_map is freed via call_rcu() */
6638 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6639 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6642 *modname = mod_map->mod->name;
6651 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6652 char *type, char *name,
6653 char *module_name, int *exported)
6655 struct ftrace_mod_map *mod_map;
6656 struct ftrace_mod_func *mod_func;
6660 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6662 if (symnum >= mod_map->num_funcs) {
6663 symnum -= mod_map->num_funcs;
6667 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6673 *value = mod_func->ip;
6675 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6676 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6684 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6685 module_name, exported);
6691 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6692 struct dyn_ftrace *rec) { }
6693 static inline struct ftrace_mod_map *
6694 allocate_ftrace_mod_map(struct module *mod,
6695 unsigned long start, unsigned long end)
6699 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6700 char *type, char *name, char *module_name,
6706 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
6707 module_name, exported);
6711 #endif /* CONFIG_MODULES */
6713 struct ftrace_init_func {
6714 struct list_head list;
6718 /* Clear any init ips from hashes */
6720 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6722 struct ftrace_func_entry *entry;
6724 entry = ftrace_lookup_ip(hash, func->ip);
6726 * Do not allow this rec to match again.
6727 * Yeah, it may waste some memory, but will be removed
6728 * if/when the hash is modified again.
6735 clear_func_from_hashes(struct ftrace_init_func *func)
6737 struct trace_array *tr;
6739 mutex_lock(&trace_types_lock);
6740 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6741 if (!tr->ops || !tr->ops->func_hash)
6743 mutex_lock(&tr->ops->func_hash->regex_lock);
6744 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6745 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6746 mutex_unlock(&tr->ops->func_hash->regex_lock);
6748 mutex_unlock(&trace_types_lock);
6751 static void add_to_clear_hash_list(struct list_head *clear_list,
6752 struct dyn_ftrace *rec)
6754 struct ftrace_init_func *func;
6756 func = kmalloc(sizeof(*func), GFP_KERNEL);
6758 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
6763 list_add(&func->list, clear_list);
6766 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6768 unsigned long start = (unsigned long)(start_ptr);
6769 unsigned long end = (unsigned long)(end_ptr);
6770 struct ftrace_page **last_pg = &ftrace_pages_start;
6771 struct ftrace_page *pg;
6772 struct dyn_ftrace *rec;
6773 struct dyn_ftrace key;
6774 struct ftrace_mod_map *mod_map = NULL;
6775 struct ftrace_init_func *func, *func_next;
6776 struct list_head clear_hash;
6779 INIT_LIST_HEAD(&clear_hash);
6782 key.flags = end; /* overload flags, as it is unsigned long */
6784 mutex_lock(&ftrace_lock);
6787 * If we are freeing module init memory, then check if
6788 * any tracer is active. If so, we need to save a mapping of
6789 * the module functions being freed with the address.
6791 if (mod && ftrace_ops_list != &ftrace_list_end)
6792 mod_map = allocate_ftrace_mod_map(mod, start, end);
6794 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6795 if (end < pg->records[0].ip ||
6796 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6799 rec = bsearch(&key, pg->records, pg->index,
6800 sizeof(struct dyn_ftrace),
6805 /* rec will be cleared from hashes after ftrace_lock unlock */
6806 add_to_clear_hash_list(&clear_hash, rec);
6809 save_ftrace_mod_rec(mod_map, rec);
6812 ftrace_update_tot_cnt--;
6814 *last_pg = pg->next;
6815 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6817 free_pages((unsigned long)pg->records, order);
6818 ftrace_number_of_pages -= 1 << order;
6819 ftrace_number_of_groups--;
6821 pg = container_of(last_pg, struct ftrace_page, next);
6826 memmove(rec, rec + 1,
6827 (pg->index - (rec - pg->records)) * sizeof(*rec));
6828 /* More than one function may be in this block */
6831 mutex_unlock(&ftrace_lock);
6833 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6834 clear_func_from_hashes(func);
6839 void __init ftrace_free_init_mem(void)
6841 void *start = (void *)(&__init_begin);
6842 void *end = (void *)(&__init_end);
6844 ftrace_free_mem(NULL, start, end);
6847 void __init ftrace_init(void)
6849 extern unsigned long __start_mcount_loc[];
6850 extern unsigned long __stop_mcount_loc[];
6851 unsigned long count, flags;
6854 local_irq_save(flags);
6855 ret = ftrace_dyn_arch_init();
6856 local_irq_restore(flags);
6860 count = __stop_mcount_loc - __start_mcount_loc;
6862 pr_info("ftrace: No functions to be traced?\n");
6866 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6867 count, count / ENTRIES_PER_PAGE + 1);
6869 last_ftrace_enabled = ftrace_enabled = 1;
6871 ret = ftrace_process_locs(NULL,
6875 pr_info("ftrace: allocated %ld pages with %ld groups\n",
6876 ftrace_number_of_pages, ftrace_number_of_groups);
6878 set_ftrace_early_filters();
6882 ftrace_disabled = 1;
6885 /* Do nothing if arch does not support this */
6886 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6890 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6892 unsigned long trampoline = ops->trampoline;
6894 arch_ftrace_update_trampoline(ops);
6895 if (ops->trampoline && ops->trampoline != trampoline &&
6896 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
6897 /* Add to kallsyms before the perf events */
6898 ftrace_add_trampoline_to_kallsyms(ops);
6899 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
6900 ops->trampoline, ops->trampoline_size, false,
6901 FTRACE_TRAMPOLINE_SYM);
6903 * Record the perf text poke event after the ksymbol register
6906 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
6907 (void *)ops->trampoline,
6908 ops->trampoline_size);
6912 void ftrace_init_trace_array(struct trace_array *tr)
6914 INIT_LIST_HEAD(&tr->func_probes);
6915 INIT_LIST_HEAD(&tr->mod_trace);
6916 INIT_LIST_HEAD(&tr->mod_notrace);
6920 struct ftrace_ops global_ops = {
6921 .func = ftrace_stub,
6922 .flags = FTRACE_OPS_FL_INITIALIZED |
6926 static int __init ftrace_nodyn_init(void)
6931 core_initcall(ftrace_nodyn_init);
6933 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6934 static inline void ftrace_startup_enable(int command) { }
6935 static inline void ftrace_startup_all(int command) { }
6937 # define ftrace_startup_sysctl() do { } while (0)
6938 # define ftrace_shutdown_sysctl() do { } while (0)
6940 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6944 #endif /* CONFIG_DYNAMIC_FTRACE */
6946 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6948 tr->ops = &global_ops;
6949 tr->ops->private = tr;
6950 ftrace_init_trace_array(tr);
6953 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6955 /* If we filter on pids, update to use the pid function */
6956 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6957 if (WARN_ON(tr->ops->func != ftrace_stub))
6958 printk("ftrace ops had %pS for function\n",
6961 tr->ops->func = func;
6962 tr->ops->private = tr;
6965 void ftrace_reset_array_ops(struct trace_array *tr)
6967 tr->ops->func = ftrace_stub;
6970 static nokprobe_inline void
6971 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6972 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
6974 struct pt_regs *regs = ftrace_get_regs(fregs);
6975 struct ftrace_ops *op;
6978 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START, TRACE_LIST_MAX);
6983 * Some of the ops may be dynamically allocated,
6984 * they must be freed after a synchronize_rcu().
6986 preempt_disable_notrace();
6988 do_for_each_ftrace_op(op, ftrace_ops_list) {
6989 /* Stub functions don't need to be called nor tested */
6990 if (op->flags & FTRACE_OPS_FL_STUB)
6993 * Check the following for each ops before calling their func:
6994 * if RCU flag is set, then rcu_is_watching() must be true
6995 * if PER_CPU is set, then ftrace_function_local_disable()
6997 * Otherwise test if the ip matches the ops filter
6999 * If any of the above fails then the op->func() is not executed.
7001 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7002 ftrace_ops_test(op, ip, regs)) {
7003 if (FTRACE_WARN_ON(!op->func)) {
7004 pr_warn("op=%p %pS\n", op, op);
7007 op->func(ip, parent_ip, op, fregs);
7009 } while_for_each_ftrace_op(op);
7011 preempt_enable_notrace();
7012 trace_clear_recursion(bit);
7016 * Some archs only support passing ip and parent_ip. Even though
7017 * the list function ignores the op parameter, we do not want any
7018 * C side effects, where a function is called without the caller
7019 * sending a third parameter.
7020 * Archs are to support both the regs and ftrace_ops at the same time.
7021 * If they support ftrace_ops, it is assumed they support regs.
7022 * If call backs want to use regs, they must either check for regs
7023 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7024 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7025 * An architecture can pass partial regs with ftrace_ops and still
7026 * set the ARCH_SUPPORTS_FTRACE_OPS.
7028 #if ARCH_SUPPORTS_FTRACE_OPS
7029 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7030 struct ftrace_ops *op, struct ftrace_regs *fregs)
7032 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7034 NOKPROBE_SYMBOL(ftrace_ops_list_func);
7036 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
7038 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7040 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
7044 * If there's only one function registered but it does not support
7045 * recursion, needs RCU protection and/or requires per cpu handling, then
7046 * this function will be called by the mcount trampoline.
7048 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7049 struct ftrace_ops *op, struct ftrace_regs *fregs)
7053 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START, TRACE_LIST_MAX);
7057 preempt_disable_notrace();
7059 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7060 op->func(ip, parent_ip, op, fregs);
7062 preempt_enable_notrace();
7063 trace_clear_recursion(bit);
7065 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7068 * ftrace_ops_get_func - get the function a trampoline should call
7069 * @ops: the ops to get the function for
7071 * Normally the mcount trampoline will call the ops->func, but there
7072 * are times that it should not. For example, if the ops does not
7073 * have its own recursion protection, then it should call the
7074 * ftrace_ops_assist_func() instead.
7076 * Returns the function that the trampoline should call for @ops.
7078 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7081 * If the function does not handle recursion or needs to be RCU safe,
7082 * then we need to call the assist handler.
7084 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7086 return ftrace_ops_assist_func;
7092 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7093 struct task_struct *prev, struct task_struct *next)
7095 struct trace_array *tr = data;
7096 struct trace_pid_list *pid_list;
7097 struct trace_pid_list *no_pid_list;
7099 pid_list = rcu_dereference_sched(tr->function_pids);
7100 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7102 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7103 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7106 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7111 ftrace_pid_follow_sched_process_fork(void *data,
7112 struct task_struct *self,
7113 struct task_struct *task)
7115 struct trace_pid_list *pid_list;
7116 struct trace_array *tr = data;
7118 pid_list = rcu_dereference_sched(tr->function_pids);
7119 trace_filter_add_remove_task(pid_list, self, task);
7121 pid_list = rcu_dereference_sched(tr->function_no_pids);
7122 trace_filter_add_remove_task(pid_list, self, task);
7126 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7128 struct trace_pid_list *pid_list;
7129 struct trace_array *tr = data;
7131 pid_list = rcu_dereference_sched(tr->function_pids);
7132 trace_filter_add_remove_task(pid_list, NULL, task);
7134 pid_list = rcu_dereference_sched(tr->function_no_pids);
7135 trace_filter_add_remove_task(pid_list, NULL, task);
7138 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7141 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7143 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7146 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7148 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7153 static void clear_ftrace_pids(struct trace_array *tr, int type)
7155 struct trace_pid_list *pid_list;
7156 struct trace_pid_list *no_pid_list;
7159 pid_list = rcu_dereference_protected(tr->function_pids,
7160 lockdep_is_held(&ftrace_lock));
7161 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7162 lockdep_is_held(&ftrace_lock));
7164 /* Make sure there's something to do */
7165 if (!pid_type_enabled(type, pid_list, no_pid_list))
7168 /* See if the pids still need to be checked after this */
7169 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7170 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7171 for_each_possible_cpu(cpu)
7172 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7175 if (type & TRACE_PIDS)
7176 rcu_assign_pointer(tr->function_pids, NULL);
7178 if (type & TRACE_NO_PIDS)
7179 rcu_assign_pointer(tr->function_no_pids, NULL);
7181 /* Wait till all users are no longer using pid filtering */
7184 if ((type & TRACE_PIDS) && pid_list)
7185 trace_free_pid_list(pid_list);
7187 if ((type & TRACE_NO_PIDS) && no_pid_list)
7188 trace_free_pid_list(no_pid_list);
7191 void ftrace_clear_pids(struct trace_array *tr)
7193 mutex_lock(&ftrace_lock);
7195 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7197 mutex_unlock(&ftrace_lock);
7200 static void ftrace_pid_reset(struct trace_array *tr, int type)
7202 mutex_lock(&ftrace_lock);
7203 clear_ftrace_pids(tr, type);
7205 ftrace_update_pid_func();
7206 ftrace_startup_all(0);
7208 mutex_unlock(&ftrace_lock);
7211 /* Greater than any max PID */
7212 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7214 static void *fpid_start(struct seq_file *m, loff_t *pos)
7217 struct trace_pid_list *pid_list;
7218 struct trace_array *tr = m->private;
7220 mutex_lock(&ftrace_lock);
7221 rcu_read_lock_sched();
7223 pid_list = rcu_dereference_sched(tr->function_pids);
7226 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7228 return trace_pid_start(pid_list, pos);
7231 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7233 struct trace_array *tr = m->private;
7234 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7236 if (v == FTRACE_NO_PIDS) {
7240 return trace_pid_next(pid_list, v, pos);
7243 static void fpid_stop(struct seq_file *m, void *p)
7246 rcu_read_unlock_sched();
7247 mutex_unlock(&ftrace_lock);
7250 static int fpid_show(struct seq_file *m, void *v)
7252 if (v == FTRACE_NO_PIDS) {
7253 seq_puts(m, "no pid\n");
7257 return trace_pid_show(m, v);
7260 static const struct seq_operations ftrace_pid_sops = {
7261 .start = fpid_start,
7267 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7270 struct trace_pid_list *pid_list;
7271 struct trace_array *tr = m->private;
7273 mutex_lock(&ftrace_lock);
7274 rcu_read_lock_sched();
7276 pid_list = rcu_dereference_sched(tr->function_no_pids);
7279 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7281 return trace_pid_start(pid_list, pos);
7284 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7286 struct trace_array *tr = m->private;
7287 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7289 if (v == FTRACE_NO_PIDS) {
7293 return trace_pid_next(pid_list, v, pos);
7296 static const struct seq_operations ftrace_no_pid_sops = {
7297 .start = fnpid_start,
7303 static int pid_open(struct inode *inode, struct file *file, int type)
7305 const struct seq_operations *seq_ops;
7306 struct trace_array *tr = inode->i_private;
7310 ret = tracing_check_open_get_tr(tr);
7314 if ((file->f_mode & FMODE_WRITE) &&
7315 (file->f_flags & O_TRUNC))
7316 ftrace_pid_reset(tr, type);
7320 seq_ops = &ftrace_pid_sops;
7323 seq_ops = &ftrace_no_pid_sops;
7326 trace_array_put(tr);
7331 ret = seq_open(file, seq_ops);
7333 trace_array_put(tr);
7335 m = file->private_data;
7336 /* copy tr over to seq ops */
7344 ftrace_pid_open(struct inode *inode, struct file *file)
7346 return pid_open(inode, file, TRACE_PIDS);
7350 ftrace_no_pid_open(struct inode *inode, struct file *file)
7352 return pid_open(inode, file, TRACE_NO_PIDS);
7355 static void ignore_task_cpu(void *data)
7357 struct trace_array *tr = data;
7358 struct trace_pid_list *pid_list;
7359 struct trace_pid_list *no_pid_list;
7362 * This function is called by on_each_cpu() while the
7363 * event_mutex is held.
7365 pid_list = rcu_dereference_protected(tr->function_pids,
7366 mutex_is_locked(&ftrace_lock));
7367 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7368 mutex_is_locked(&ftrace_lock));
7370 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7371 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7374 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7379 pid_write(struct file *filp, const char __user *ubuf,
7380 size_t cnt, loff_t *ppos, int type)
7382 struct seq_file *m = filp->private_data;
7383 struct trace_array *tr = m->private;
7384 struct trace_pid_list *filtered_pids;
7385 struct trace_pid_list *other_pids;
7386 struct trace_pid_list *pid_list;
7392 mutex_lock(&ftrace_lock);
7396 filtered_pids = rcu_dereference_protected(tr->function_pids,
7397 lockdep_is_held(&ftrace_lock));
7398 other_pids = rcu_dereference_protected(tr->function_no_pids,
7399 lockdep_is_held(&ftrace_lock));
7402 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7403 lockdep_is_held(&ftrace_lock));
7404 other_pids = rcu_dereference_protected(tr->function_pids,
7405 lockdep_is_held(&ftrace_lock));
7413 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7419 rcu_assign_pointer(tr->function_pids, pid_list);
7422 rcu_assign_pointer(tr->function_no_pids, pid_list);
7427 if (filtered_pids) {
7429 trace_free_pid_list(filtered_pids);
7430 } else if (pid_list && !other_pids) {
7431 /* Register a probe to set whether to ignore the tracing of a task */
7432 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7436 * Ignoring of pids is done at task switch. But we have to
7437 * check for those tasks that are currently running.
7438 * Always do this in case a pid was appended or removed.
7440 on_each_cpu(ignore_task_cpu, tr, 1);
7442 ftrace_update_pid_func();
7443 ftrace_startup_all(0);
7445 mutex_unlock(&ftrace_lock);
7454 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7455 size_t cnt, loff_t *ppos)
7457 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7461 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7462 size_t cnt, loff_t *ppos)
7464 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7468 ftrace_pid_release(struct inode *inode, struct file *file)
7470 struct trace_array *tr = inode->i_private;
7472 trace_array_put(tr);
7474 return seq_release(inode, file);
7477 static const struct file_operations ftrace_pid_fops = {
7478 .open = ftrace_pid_open,
7479 .write = ftrace_pid_write,
7481 .llseek = tracing_lseek,
7482 .release = ftrace_pid_release,
7485 static const struct file_operations ftrace_no_pid_fops = {
7486 .open = ftrace_no_pid_open,
7487 .write = ftrace_no_pid_write,
7489 .llseek = tracing_lseek,
7490 .release = ftrace_pid_release,
7493 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7495 trace_create_file("set_ftrace_pid", 0644, d_tracer,
7496 tr, &ftrace_pid_fops);
7497 trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
7498 tr, &ftrace_no_pid_fops);
7501 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7502 struct dentry *d_tracer)
7504 /* Only the top level directory has the dyn_tracefs and profile */
7505 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7507 ftrace_init_dyn_tracefs(d_tracer);
7508 ftrace_profile_tracefs(d_tracer);
7512 * ftrace_kill - kill ftrace
7514 * This function should be used by panic code. It stops ftrace
7515 * but in a not so nice way. If you need to simply kill ftrace
7516 * from a non-atomic section, use ftrace_kill.
7518 void ftrace_kill(void)
7520 ftrace_disabled = 1;
7522 ftrace_trace_function = ftrace_stub;
7526 * Test if ftrace is dead or not.
7528 int ftrace_is_dead(void)
7530 return ftrace_disabled;
7534 * register_ftrace_function - register a function for profiling
7535 * @ops - ops structure that holds the function for profiling.
7537 * Register a function to be called by all functions in the
7540 * Note: @ops->func and all the functions it calls must be labeled
7541 * with "notrace", otherwise it will go into a
7544 int register_ftrace_function(struct ftrace_ops *ops)
7548 ftrace_ops_init(ops);
7550 mutex_lock(&ftrace_lock);
7552 ret = ftrace_startup(ops, 0);
7554 mutex_unlock(&ftrace_lock);
7558 EXPORT_SYMBOL_GPL(register_ftrace_function);
7561 * unregister_ftrace_function - unregister a function for profiling.
7562 * @ops - ops structure that holds the function to unregister
7564 * Unregister a function that was added to be called by ftrace profiling.
7566 int unregister_ftrace_function(struct ftrace_ops *ops)
7570 mutex_lock(&ftrace_lock);
7571 ret = ftrace_shutdown(ops, 0);
7572 mutex_unlock(&ftrace_lock);
7576 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
7578 static bool is_permanent_ops_registered(void)
7580 struct ftrace_ops *op;
7582 do_for_each_ftrace_op(op, ftrace_ops_list) {
7583 if (op->flags & FTRACE_OPS_FL_PERMANENT)
7585 } while_for_each_ftrace_op(op);
7591 ftrace_enable_sysctl(struct ctl_table *table, int write,
7592 void *buffer, size_t *lenp, loff_t *ppos)
7596 mutex_lock(&ftrace_lock);
7598 if (unlikely(ftrace_disabled))
7601 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7603 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
7606 if (ftrace_enabled) {
7608 /* we are starting ftrace again */
7609 if (rcu_dereference_protected(ftrace_ops_list,
7610 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
7611 update_ftrace_function();
7613 ftrace_startup_sysctl();
7616 if (is_permanent_ops_registered()) {
7617 ftrace_enabled = true;
7622 /* stopping ftrace calls (just send to ftrace_stub) */
7623 ftrace_trace_function = ftrace_stub;
7625 ftrace_shutdown_sysctl();
7628 last_ftrace_enabled = !!ftrace_enabled;
7630 mutex_unlock(&ftrace_lock);