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 /* Flags that do not get reset */
49 #define FTRACE_NOCLEAR_FLAGS (FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
52 #define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
54 #define FTRACE_WARN_ON(cond) \
62 #define FTRACE_WARN_ON_ONCE(cond) \
65 if (WARN_ON_ONCE(___r)) \
70 /* hash bits for specific function selection */
71 #define FTRACE_HASH_DEFAULT_BITS 10
72 #define FTRACE_HASH_MAX_BITS 12
74 #ifdef CONFIG_DYNAMIC_FTRACE
75 #define INIT_OPS_HASH(opsname) \
76 .func_hash = &opsname.local_hash, \
77 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
79 #define INIT_OPS_HASH(opsname)
83 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
84 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
87 struct ftrace_ops ftrace_list_end __read_mostly = {
89 .flags = FTRACE_OPS_FL_STUB,
90 INIT_OPS_HASH(ftrace_list_end)
93 /* ftrace_enabled is a method to turn ftrace on or off */
94 int ftrace_enabled __read_mostly;
95 static int __maybe_unused last_ftrace_enabled;
97 /* Current function tracing op */
98 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
99 /* What to set function_trace_op to */
100 static struct ftrace_ops *set_function_trace_op;
102 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
104 struct trace_array *tr;
106 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
111 return tr->function_pids != NULL || tr->function_no_pids != NULL;
114 static void ftrace_update_trampoline(struct ftrace_ops *ops);
117 * ftrace_disabled is set when an anomaly is discovered.
118 * ftrace_disabled is much stronger than ftrace_enabled.
120 static int ftrace_disabled __read_mostly;
122 DEFINE_MUTEX(ftrace_lock);
124 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
125 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
126 struct ftrace_ops global_ops;
128 /* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
129 void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
130 struct ftrace_ops *op, struct ftrace_regs *fregs);
132 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
134 * Stub used to invoke the list ops without requiring a separate trampoline.
136 const struct ftrace_ops ftrace_list_ops = {
137 .func = ftrace_ops_list_func,
138 .flags = FTRACE_OPS_FL_STUB,
141 static void ftrace_ops_nop_func(unsigned long ip, unsigned long parent_ip,
142 struct ftrace_ops *op,
143 struct ftrace_regs *fregs)
149 * Stub used when a call site is disabled. May be called transiently by threads
150 * which have made it into ftrace_caller but haven't yet recovered the ops at
151 * the point the call site is disabled.
153 const struct ftrace_ops ftrace_nop_ops = {
154 .func = ftrace_ops_nop_func,
155 .flags = FTRACE_OPS_FL_STUB,
159 static inline void ftrace_ops_init(struct ftrace_ops *ops)
161 #ifdef CONFIG_DYNAMIC_FTRACE
162 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
163 mutex_init(&ops->local_hash.regex_lock);
164 ops->func_hash = &ops->local_hash;
165 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
170 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
171 struct ftrace_ops *op, struct ftrace_regs *fregs)
173 struct trace_array *tr = op->private;
177 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
178 if (pid == FTRACE_PID_IGNORE)
180 if (pid != FTRACE_PID_TRACE &&
185 op->saved_func(ip, parent_ip, op, fregs);
188 static void ftrace_sync_ipi(void *data)
190 /* Probably not needed, but do it anyway */
194 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
197 * If this is a dynamic or RCU ops, or we force list func,
198 * then it needs to call the list anyway.
200 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
201 FTRACE_FORCE_LIST_FUNC)
202 return ftrace_ops_list_func;
204 return ftrace_ops_get_func(ops);
207 static void update_ftrace_function(void)
212 * Prepare the ftrace_ops that the arch callback will use.
213 * If there's only one ftrace_ops registered, the ftrace_ops_list
214 * will point to the ops we want.
216 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
217 lockdep_is_held(&ftrace_lock));
219 /* If there's no ftrace_ops registered, just call the stub function */
220 if (set_function_trace_op == &ftrace_list_end) {
224 * If we are at the end of the list and this ops is
225 * recursion safe and not dynamic and the arch supports passing ops,
226 * then have the mcount trampoline call the function directly.
228 } else if (rcu_dereference_protected(ftrace_ops_list->next,
229 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
230 func = ftrace_ops_get_list_func(ftrace_ops_list);
233 /* Just use the default ftrace_ops */
234 set_function_trace_op = &ftrace_list_end;
235 func = ftrace_ops_list_func;
238 update_function_graph_func();
240 /* If there's no change, then do nothing more here */
241 if (ftrace_trace_function == func)
245 * If we are using the list function, it doesn't care
246 * about the function_trace_ops.
248 if (func == ftrace_ops_list_func) {
249 ftrace_trace_function = func;
251 * Don't even bother setting function_trace_ops,
252 * it would be racy to do so anyway.
257 #ifndef CONFIG_DYNAMIC_FTRACE
259 * For static tracing, we need to be a bit more careful.
260 * The function change takes affect immediately. Thus,
261 * we need to coordinate the setting of the function_trace_ops
262 * with the setting of the ftrace_trace_function.
264 * Set the function to the list ops, which will call the
265 * function we want, albeit indirectly, but it handles the
266 * ftrace_ops and doesn't depend on function_trace_op.
268 ftrace_trace_function = ftrace_ops_list_func;
270 * Make sure all CPUs see this. Yes this is slow, but static
271 * tracing is slow and nasty to have enabled.
273 synchronize_rcu_tasks_rude();
274 /* Now all cpus are using the list ops. */
275 function_trace_op = set_function_trace_op;
276 /* Make sure the function_trace_op is visible on all CPUs */
278 /* Nasty way to force a rmb on all cpus */
279 smp_call_function(ftrace_sync_ipi, NULL, 1);
280 /* OK, we are all set to update the ftrace_trace_function now! */
281 #endif /* !CONFIG_DYNAMIC_FTRACE */
283 ftrace_trace_function = func;
286 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
287 struct ftrace_ops *ops)
289 rcu_assign_pointer(ops->next, *list);
292 * We are entering ops into the list but another
293 * CPU might be walking that list. We need to make sure
294 * the ops->next pointer is valid before another CPU sees
295 * the ops pointer included into the list.
297 rcu_assign_pointer(*list, ops);
300 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
301 struct ftrace_ops *ops)
303 struct ftrace_ops **p;
306 * If we are removing the last function, then simply point
307 * to the ftrace_stub.
309 if (rcu_dereference_protected(*list,
310 lockdep_is_held(&ftrace_lock)) == ops &&
311 rcu_dereference_protected(ops->next,
312 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
313 *list = &ftrace_list_end;
317 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
328 static void ftrace_update_trampoline(struct ftrace_ops *ops);
330 int __register_ftrace_function(struct ftrace_ops *ops)
332 if (ops->flags & FTRACE_OPS_FL_DELETED)
335 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
338 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
340 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
341 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
342 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
344 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
345 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
348 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
349 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
351 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
354 if (!is_kernel_core_data((unsigned long)ops))
355 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
357 add_ftrace_ops(&ftrace_ops_list, ops);
359 /* Always save the function, and reset at unregistering */
360 ops->saved_func = ops->func;
362 if (ftrace_pids_enabled(ops))
363 ops->func = ftrace_pid_func;
365 ftrace_update_trampoline(ops);
368 update_ftrace_function();
373 int __unregister_ftrace_function(struct ftrace_ops *ops)
377 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
380 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
386 update_ftrace_function();
388 ops->func = ops->saved_func;
393 static void ftrace_update_pid_func(void)
395 struct ftrace_ops *op;
397 /* Only do something if we are tracing something */
398 if (ftrace_trace_function == ftrace_stub)
401 do_for_each_ftrace_op(op, ftrace_ops_list) {
402 if (op->flags & FTRACE_OPS_FL_PID) {
403 op->func = ftrace_pids_enabled(op) ?
404 ftrace_pid_func : op->saved_func;
405 ftrace_update_trampoline(op);
407 } while_for_each_ftrace_op(op);
409 update_ftrace_function();
412 #ifdef CONFIG_FUNCTION_PROFILER
413 struct ftrace_profile {
414 struct hlist_node node;
416 unsigned long counter;
417 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
418 unsigned long long time;
419 unsigned long long time_squared;
423 struct ftrace_profile_page {
424 struct ftrace_profile_page *next;
426 struct ftrace_profile records[];
429 struct ftrace_profile_stat {
431 struct hlist_head *hash;
432 struct ftrace_profile_page *pages;
433 struct ftrace_profile_page *start;
434 struct tracer_stat stat;
437 #define PROFILE_RECORDS_SIZE \
438 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
440 #define PROFILES_PER_PAGE \
441 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
443 static int ftrace_profile_enabled __read_mostly;
445 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
446 static DEFINE_MUTEX(ftrace_profile_lock);
448 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
450 #define FTRACE_PROFILE_HASH_BITS 10
451 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
454 function_stat_next(void *v, int idx)
456 struct ftrace_profile *rec = v;
457 struct ftrace_profile_page *pg;
459 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
465 if ((void *)rec >= (void *)&pg->records[pg->index]) {
469 rec = &pg->records[0];
477 static void *function_stat_start(struct tracer_stat *trace)
479 struct ftrace_profile_stat *stat =
480 container_of(trace, struct ftrace_profile_stat, stat);
482 if (!stat || !stat->start)
485 return function_stat_next(&stat->start->records[0], 0);
488 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
489 /* function graph compares on total time */
490 static int function_stat_cmp(const void *p1, const void *p2)
492 const struct ftrace_profile *a = p1;
493 const struct ftrace_profile *b = p2;
495 if (a->time < b->time)
497 if (a->time > b->time)
503 /* not function graph compares against hits */
504 static int function_stat_cmp(const void *p1, const void *p2)
506 const struct ftrace_profile *a = p1;
507 const struct ftrace_profile *b = p2;
509 if (a->counter < b->counter)
511 if (a->counter > b->counter)
518 static int function_stat_headers(struct seq_file *m)
520 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
521 seq_puts(m, " Function "
524 "--- ---- --- ---\n");
526 seq_puts(m, " Function Hit\n"
532 static int function_stat_show(struct seq_file *m, void *v)
534 struct ftrace_profile *rec = v;
535 char str[KSYM_SYMBOL_LEN];
537 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
538 static struct trace_seq s;
539 unsigned long long avg;
540 unsigned long long stddev;
542 mutex_lock(&ftrace_profile_lock);
544 /* we raced with function_profile_reset() */
545 if (unlikely(rec->counter == 0)) {
550 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
551 avg = div64_ul(rec->time, rec->counter);
552 if (tracing_thresh && (avg < tracing_thresh))
556 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
557 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
559 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
562 /* Sample standard deviation (s^2) */
563 if (rec->counter <= 1)
567 * Apply Welford's method:
568 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
570 stddev = rec->counter * rec->time_squared -
571 rec->time * rec->time;
574 * Divide only 1000 for ns^2 -> us^2 conversion.
575 * trace_print_graph_duration will divide 1000 again.
577 stddev = div64_ul(stddev,
578 rec->counter * (rec->counter - 1) * 1000);
582 trace_print_graph_duration(rec->time, &s);
583 trace_seq_puts(&s, " ");
584 trace_print_graph_duration(avg, &s);
585 trace_seq_puts(&s, " ");
586 trace_print_graph_duration(stddev, &s);
587 trace_print_seq(m, &s);
591 mutex_unlock(&ftrace_profile_lock);
596 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
598 struct ftrace_profile_page *pg;
600 pg = stat->pages = stat->start;
603 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
608 memset(stat->hash, 0,
609 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
612 static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
614 struct ftrace_profile_page *pg;
619 /* If we already allocated, do nothing */
623 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
627 #ifdef CONFIG_DYNAMIC_FTRACE
628 functions = ftrace_update_tot_cnt;
631 * We do not know the number of functions that exist because
632 * dynamic tracing is what counts them. With past experience
633 * we have around 20K functions. That should be more than enough.
634 * It is highly unlikely we will execute every function in
640 pg = stat->start = stat->pages;
642 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
644 for (i = 1; i < pages; i++) {
645 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
656 unsigned long tmp = (unsigned long)pg;
668 static int ftrace_profile_init_cpu(int cpu)
670 struct ftrace_profile_stat *stat;
673 stat = &per_cpu(ftrace_profile_stats, cpu);
676 /* If the profile is already created, simply reset it */
677 ftrace_profile_reset(stat);
682 * We are profiling all functions, but usually only a few thousand
683 * functions are hit. We'll make a hash of 1024 items.
685 size = FTRACE_PROFILE_HASH_SIZE;
687 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
692 /* Preallocate the function profiling pages */
693 if (ftrace_profile_pages_init(stat) < 0) {
702 static int ftrace_profile_init(void)
707 for_each_possible_cpu(cpu) {
708 ret = ftrace_profile_init_cpu(cpu);
716 /* interrupts must be disabled */
717 static struct ftrace_profile *
718 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
720 struct ftrace_profile *rec;
721 struct hlist_head *hhd;
724 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
725 hhd = &stat->hash[key];
727 if (hlist_empty(hhd))
730 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
738 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
739 struct ftrace_profile *rec)
743 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
744 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
748 * The memory is already allocated, this simply finds a new record to use.
750 static struct ftrace_profile *
751 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
753 struct ftrace_profile *rec = NULL;
755 /* prevent recursion (from NMIs) */
756 if (atomic_inc_return(&stat->disabled) != 1)
760 * Try to find the function again since an NMI
761 * could have added it
763 rec = ftrace_find_profiled_func(stat, ip);
767 if (stat->pages->index == PROFILES_PER_PAGE) {
768 if (!stat->pages->next)
770 stat->pages = stat->pages->next;
773 rec = &stat->pages->records[stat->pages->index++];
775 ftrace_add_profile(stat, rec);
778 atomic_dec(&stat->disabled);
784 function_profile_call(unsigned long ip, unsigned long parent_ip,
785 struct ftrace_ops *ops, struct ftrace_regs *fregs)
787 struct ftrace_profile_stat *stat;
788 struct ftrace_profile *rec;
791 if (!ftrace_profile_enabled)
794 local_irq_save(flags);
796 stat = this_cpu_ptr(&ftrace_profile_stats);
797 if (!stat->hash || !ftrace_profile_enabled)
800 rec = ftrace_find_profiled_func(stat, ip);
802 rec = ftrace_profile_alloc(stat, ip);
809 local_irq_restore(flags);
812 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
813 static bool fgraph_graph_time = true;
815 void ftrace_graph_graph_time_control(bool enable)
817 fgraph_graph_time = enable;
820 static int profile_graph_entry(struct ftrace_graph_ent *trace)
822 struct ftrace_ret_stack *ret_stack;
824 function_profile_call(trace->func, 0, NULL, NULL);
826 /* If function graph is shutting down, ret_stack can be NULL */
827 if (!current->ret_stack)
830 ret_stack = ftrace_graph_get_ret_stack(current, 0);
832 ret_stack->subtime = 0;
837 static void profile_graph_return(struct ftrace_graph_ret *trace)
839 struct ftrace_ret_stack *ret_stack;
840 struct ftrace_profile_stat *stat;
841 unsigned long long calltime;
842 struct ftrace_profile *rec;
845 local_irq_save(flags);
846 stat = this_cpu_ptr(&ftrace_profile_stats);
847 if (!stat->hash || !ftrace_profile_enabled)
850 /* If the calltime was zero'd ignore it */
851 if (!trace->calltime)
854 calltime = trace->rettime - trace->calltime;
856 if (!fgraph_graph_time) {
858 /* Append this call time to the parent time to subtract */
859 ret_stack = ftrace_graph_get_ret_stack(current, 1);
861 ret_stack->subtime += calltime;
863 ret_stack = ftrace_graph_get_ret_stack(current, 0);
864 if (ret_stack && ret_stack->subtime < calltime)
865 calltime -= ret_stack->subtime;
870 rec = ftrace_find_profiled_func(stat, trace->func);
872 rec->time += calltime;
873 rec->time_squared += calltime * calltime;
877 local_irq_restore(flags);
880 static struct fgraph_ops fprofiler_ops = {
881 .entryfunc = &profile_graph_entry,
882 .retfunc = &profile_graph_return,
885 static int register_ftrace_profiler(void)
887 return register_ftrace_graph(&fprofiler_ops);
890 static void unregister_ftrace_profiler(void)
892 unregister_ftrace_graph(&fprofiler_ops);
895 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
896 .func = function_profile_call,
897 .flags = FTRACE_OPS_FL_INITIALIZED,
898 INIT_OPS_HASH(ftrace_profile_ops)
901 static int register_ftrace_profiler(void)
903 return register_ftrace_function(&ftrace_profile_ops);
906 static void unregister_ftrace_profiler(void)
908 unregister_ftrace_function(&ftrace_profile_ops);
910 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
913 ftrace_profile_write(struct file *filp, const char __user *ubuf,
914 size_t cnt, loff_t *ppos)
919 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
925 mutex_lock(&ftrace_profile_lock);
926 if (ftrace_profile_enabled ^ val) {
928 ret = ftrace_profile_init();
934 ret = register_ftrace_profiler();
939 ftrace_profile_enabled = 1;
941 ftrace_profile_enabled = 0;
943 * unregister_ftrace_profiler calls stop_machine
944 * so this acts like an synchronize_rcu.
946 unregister_ftrace_profiler();
950 mutex_unlock(&ftrace_profile_lock);
958 ftrace_profile_read(struct file *filp, char __user *ubuf,
959 size_t cnt, loff_t *ppos)
961 char buf[64]; /* big enough to hold a number */
964 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
965 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
968 static const struct file_operations ftrace_profile_fops = {
969 .open = tracing_open_generic,
970 .read = ftrace_profile_read,
971 .write = ftrace_profile_write,
972 .llseek = default_llseek,
975 /* used to initialize the real stat files */
976 static struct tracer_stat function_stats __initdata = {
978 .stat_start = function_stat_start,
979 .stat_next = function_stat_next,
980 .stat_cmp = function_stat_cmp,
981 .stat_headers = function_stat_headers,
982 .stat_show = function_stat_show
985 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
987 struct ftrace_profile_stat *stat;
992 for_each_possible_cpu(cpu) {
993 stat = &per_cpu(ftrace_profile_stats, cpu);
995 name = kasprintf(GFP_KERNEL, "function%d", cpu);
998 * The files created are permanent, if something happens
999 * we still do not free memory.
1002 "Could not allocate stat file for cpu %d\n",
1006 stat->stat = function_stats;
1007 stat->stat.name = name;
1008 ret = register_stat_tracer(&stat->stat);
1011 "Could not register function stat for cpu %d\n",
1018 trace_create_file("function_profile_enabled",
1019 TRACE_MODE_WRITE, d_tracer, NULL,
1020 &ftrace_profile_fops);
1023 #else /* CONFIG_FUNCTION_PROFILER */
1024 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1027 #endif /* CONFIG_FUNCTION_PROFILER */
1029 #ifdef CONFIG_DYNAMIC_FTRACE
1031 static struct ftrace_ops *removed_ops;
1034 * Set when doing a global update, like enabling all recs or disabling them.
1035 * It is not set when just updating a single ftrace_ops.
1037 static bool update_all_ops;
1039 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1040 # error Dynamic ftrace depends on MCOUNT_RECORD
1043 struct ftrace_func_probe {
1044 struct ftrace_probe_ops *probe_ops;
1045 struct ftrace_ops ops;
1046 struct trace_array *tr;
1047 struct list_head list;
1053 * We make these constant because no one should touch them,
1054 * but they are used as the default "empty hash", to avoid allocating
1055 * it all the time. These are in a read only section such that if
1056 * anyone does try to modify it, it will cause an exception.
1058 static const struct hlist_head empty_buckets[1];
1059 static const struct ftrace_hash empty_hash = {
1060 .buckets = (struct hlist_head *)empty_buckets,
1062 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1064 struct ftrace_ops global_ops = {
1065 .func = ftrace_stub,
1066 .local_hash.notrace_hash = EMPTY_HASH,
1067 .local_hash.filter_hash = EMPTY_HASH,
1068 INIT_OPS_HASH(global_ops)
1069 .flags = FTRACE_OPS_FL_INITIALIZED |
1074 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1076 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1078 struct ftrace_ops *op = NULL;
1081 * Some of the ops may be dynamically allocated,
1082 * they are freed after a synchronize_rcu().
1084 preempt_disable_notrace();
1086 do_for_each_ftrace_op(op, ftrace_ops_list) {
1088 * This is to check for dynamically allocated trampolines.
1089 * Trampolines that are in kernel text will have
1090 * core_kernel_text() return true.
1092 if (op->trampoline && op->trampoline_size)
1093 if (addr >= op->trampoline &&
1094 addr < op->trampoline + op->trampoline_size) {
1095 preempt_enable_notrace();
1098 } while_for_each_ftrace_op(op);
1099 preempt_enable_notrace();
1105 * This is used by __kernel_text_address() to return true if the
1106 * address is on a dynamically allocated trampoline that would
1107 * not return true for either core_kernel_text() or
1108 * is_module_text_address().
1110 bool is_ftrace_trampoline(unsigned long addr)
1112 return ftrace_ops_trampoline(addr) != NULL;
1115 struct ftrace_page {
1116 struct ftrace_page *next;
1117 struct dyn_ftrace *records;
1122 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1123 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1125 static struct ftrace_page *ftrace_pages_start;
1126 static struct ftrace_page *ftrace_pages;
1128 static __always_inline unsigned long
1129 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1131 if (hash->size_bits > 0)
1132 return hash_long(ip, hash->size_bits);
1137 /* Only use this function if ftrace_hash_empty() has already been tested */
1138 static __always_inline struct ftrace_func_entry *
1139 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1142 struct ftrace_func_entry *entry;
1143 struct hlist_head *hhd;
1145 key = ftrace_hash_key(hash, ip);
1146 hhd = &hash->buckets[key];
1148 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1149 if (entry->ip == ip)
1156 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1157 * @hash: The hash to look at
1158 * @ip: The instruction pointer to test
1160 * Search a given @hash to see if a given instruction pointer (@ip)
1163 * Returns the entry that holds the @ip if found. NULL otherwise.
1165 struct ftrace_func_entry *
1166 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1168 if (ftrace_hash_empty(hash))
1171 return __ftrace_lookup_ip(hash, ip);
1174 static void __add_hash_entry(struct ftrace_hash *hash,
1175 struct ftrace_func_entry *entry)
1177 struct hlist_head *hhd;
1180 key = ftrace_hash_key(hash, entry->ip);
1181 hhd = &hash->buckets[key];
1182 hlist_add_head(&entry->hlist, hhd);
1186 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1188 struct ftrace_func_entry *entry;
1190 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1195 __add_hash_entry(hash, entry);
1201 free_hash_entry(struct ftrace_hash *hash,
1202 struct ftrace_func_entry *entry)
1204 hlist_del(&entry->hlist);
1210 remove_hash_entry(struct ftrace_hash *hash,
1211 struct ftrace_func_entry *entry)
1213 hlist_del_rcu(&entry->hlist);
1217 static void ftrace_hash_clear(struct ftrace_hash *hash)
1219 struct hlist_head *hhd;
1220 struct hlist_node *tn;
1221 struct ftrace_func_entry *entry;
1222 int size = 1 << hash->size_bits;
1228 for (i = 0; i < size; i++) {
1229 hhd = &hash->buckets[i];
1230 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1231 free_hash_entry(hash, entry);
1233 FTRACE_WARN_ON(hash->count);
1236 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1238 list_del(&ftrace_mod->list);
1239 kfree(ftrace_mod->module);
1240 kfree(ftrace_mod->func);
1244 static void clear_ftrace_mod_list(struct list_head *head)
1246 struct ftrace_mod_load *p, *n;
1248 /* stack tracer isn't supported yet */
1252 mutex_lock(&ftrace_lock);
1253 list_for_each_entry_safe(p, n, head, list)
1255 mutex_unlock(&ftrace_lock);
1258 static void free_ftrace_hash(struct ftrace_hash *hash)
1260 if (!hash || hash == EMPTY_HASH)
1262 ftrace_hash_clear(hash);
1263 kfree(hash->buckets);
1267 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1269 struct ftrace_hash *hash;
1271 hash = container_of(rcu, struct ftrace_hash, rcu);
1272 free_ftrace_hash(hash);
1275 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1277 if (!hash || hash == EMPTY_HASH)
1279 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1283 * ftrace_free_filter - remove all filters for an ftrace_ops
1284 * @ops - the ops to remove the filters from
1286 void ftrace_free_filter(struct ftrace_ops *ops)
1288 ftrace_ops_init(ops);
1289 free_ftrace_hash(ops->func_hash->filter_hash);
1290 free_ftrace_hash(ops->func_hash->notrace_hash);
1292 EXPORT_SYMBOL_GPL(ftrace_free_filter);
1294 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1296 struct ftrace_hash *hash;
1299 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1303 size = 1 << size_bits;
1304 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1306 if (!hash->buckets) {
1311 hash->size_bits = size_bits;
1317 static int ftrace_add_mod(struct trace_array *tr,
1318 const char *func, const char *module,
1321 struct ftrace_mod_load *ftrace_mod;
1322 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1324 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1328 INIT_LIST_HEAD(&ftrace_mod->list);
1329 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1330 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1331 ftrace_mod->enable = enable;
1333 if (!ftrace_mod->func || !ftrace_mod->module)
1336 list_add(&ftrace_mod->list, mod_head);
1341 free_ftrace_mod(ftrace_mod);
1346 static struct ftrace_hash *
1347 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1349 struct ftrace_func_entry *entry;
1350 struct ftrace_hash *new_hash;
1355 new_hash = alloc_ftrace_hash(size_bits);
1360 new_hash->flags = hash->flags;
1363 if (ftrace_hash_empty(hash))
1366 size = 1 << hash->size_bits;
1367 for (i = 0; i < size; i++) {
1368 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1369 ret = add_hash_entry(new_hash, entry->ip);
1375 FTRACE_WARN_ON(new_hash->count != hash->count);
1380 free_ftrace_hash(new_hash);
1385 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1387 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1389 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1390 struct ftrace_hash *new_hash);
1392 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1394 struct ftrace_func_entry *entry;
1395 struct ftrace_hash *new_hash;
1396 struct hlist_head *hhd;
1397 struct hlist_node *tn;
1402 * Use around half the size (max bit of it), but
1403 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1405 bits = fls(size / 2);
1407 /* Don't allocate too much */
1408 if (bits > FTRACE_HASH_MAX_BITS)
1409 bits = FTRACE_HASH_MAX_BITS;
1411 new_hash = alloc_ftrace_hash(bits);
1415 new_hash->flags = src->flags;
1417 size = 1 << src->size_bits;
1418 for (i = 0; i < size; i++) {
1419 hhd = &src->buckets[i];
1420 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1421 remove_hash_entry(src, entry);
1422 __add_hash_entry(new_hash, entry);
1428 static struct ftrace_hash *
1429 __ftrace_hash_move(struct ftrace_hash *src)
1431 int size = src->count;
1434 * If the new source is empty, just return the empty_hash.
1436 if (ftrace_hash_empty(src))
1439 return dup_hash(src, size);
1443 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1444 struct ftrace_hash **dst, struct ftrace_hash *src)
1446 struct ftrace_hash *new_hash;
1449 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1450 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1453 new_hash = __ftrace_hash_move(src);
1457 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1459 /* IPMODIFY should be updated only when filter_hash updating */
1460 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1462 free_ftrace_hash(new_hash);
1468 * Remove the current set, update the hash and add
1471 ftrace_hash_rec_disable_modify(ops, enable);
1473 rcu_assign_pointer(*dst, new_hash);
1475 ftrace_hash_rec_enable_modify(ops, enable);
1480 static bool hash_contains_ip(unsigned long ip,
1481 struct ftrace_ops_hash *hash)
1484 * The function record is a match if it exists in the filter
1485 * hash and not in the notrace hash. Note, an empty hash is
1486 * considered a match for the filter hash, but an empty
1487 * notrace hash is considered not in the notrace hash.
1489 return (ftrace_hash_empty(hash->filter_hash) ||
1490 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1491 (ftrace_hash_empty(hash->notrace_hash) ||
1492 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1496 * Test the hashes for this ops to see if we want to call
1497 * the ops->func or not.
1499 * It's a match if the ip is in the ops->filter_hash or
1500 * the filter_hash does not exist or is empty,
1502 * the ip is not in the ops->notrace_hash.
1504 * This needs to be called with preemption disabled as
1505 * the hashes are freed with call_rcu().
1508 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1510 struct ftrace_ops_hash hash;
1513 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1515 * There's a small race when adding ops that the ftrace handler
1516 * that wants regs, may be called without them. We can not
1517 * allow that handler to be called if regs is NULL.
1519 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1523 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1524 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1526 if (hash_contains_ip(ip, &hash))
1535 * This is a double for. Do not use 'break' to break out of the loop,
1536 * you must use a goto.
1538 #define do_for_each_ftrace_rec(pg, rec) \
1539 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1541 for (_____i = 0; _____i < pg->index; _____i++) { \
1542 rec = &pg->records[_____i];
1544 #define while_for_each_ftrace_rec() \
1549 static int ftrace_cmp_recs(const void *a, const void *b)
1551 const struct dyn_ftrace *key = a;
1552 const struct dyn_ftrace *rec = b;
1554 if (key->flags < rec->ip)
1556 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1561 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1563 struct ftrace_page *pg;
1564 struct dyn_ftrace *rec = NULL;
1565 struct dyn_ftrace key;
1568 key.flags = end; /* overload flags, as it is unsigned long */
1570 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1571 if (pg->index == 0 ||
1572 end < pg->records[0].ip ||
1573 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1575 rec = bsearch(&key, pg->records, pg->index,
1576 sizeof(struct dyn_ftrace),
1585 * ftrace_location_range - return the first address of a traced location
1586 * if it touches the given ip range
1587 * @start: start of range to search.
1588 * @end: end of range to search (inclusive). @end points to the last byte
1591 * Returns rec->ip if the related ftrace location is a least partly within
1592 * the given address range. That is, the first address of the instruction
1593 * that is either a NOP or call to the function tracer. It checks the ftrace
1594 * internal tables to determine if the address belongs or not.
1596 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1598 struct dyn_ftrace *rec;
1600 rec = lookup_rec(start, end);
1608 * ftrace_location - return the ftrace location
1609 * @ip: the instruction pointer to check
1611 * If @ip matches the ftrace location, return @ip.
1612 * If @ip matches sym+0, return sym's ftrace location.
1613 * Otherwise, return 0.
1615 unsigned long ftrace_location(unsigned long ip)
1617 struct dyn_ftrace *rec;
1618 unsigned long offset;
1621 rec = lookup_rec(ip, ip);
1623 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1626 /* map sym+0 to __fentry__ */
1628 rec = lookup_rec(ip, ip + size - 1);
1639 * ftrace_text_reserved - return true if range contains an ftrace location
1640 * @start: start of range to search
1641 * @end: end of range to search (inclusive). @end points to the last byte to check.
1643 * Returns 1 if @start and @end contains a ftrace location.
1644 * That is, the instruction that is either a NOP or call to
1645 * the function tracer. It checks the ftrace internal tables to
1646 * determine if the address belongs or not.
1648 int ftrace_text_reserved(const void *start, const void *end)
1652 ret = ftrace_location_range((unsigned long)start,
1653 (unsigned long)end);
1658 /* Test if ops registered to this rec needs regs */
1659 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1661 struct ftrace_ops *ops;
1662 bool keep_regs = false;
1664 for (ops = ftrace_ops_list;
1665 ops != &ftrace_list_end; ops = ops->next) {
1666 /* pass rec in as regs to have non-NULL val */
1667 if (ftrace_ops_test(ops, rec->ip, rec)) {
1668 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1678 static struct ftrace_ops *
1679 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1680 static struct ftrace_ops *
1681 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1682 static struct ftrace_ops *
1683 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1685 static bool skip_record(struct dyn_ftrace *rec)
1688 * At boot up, weak functions are set to disable. Function tracing
1689 * can be enabled before they are, and they still need to be disabled now.
1690 * If the record is disabled, still continue if it is marked as already
1691 * enabled (this is needed to keep the accounting working).
1693 return rec->flags & FTRACE_FL_DISABLED &&
1694 !(rec->flags & FTRACE_FL_ENABLED);
1697 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1701 struct ftrace_hash *hash;
1702 struct ftrace_hash *other_hash;
1703 struct ftrace_page *pg;
1704 struct dyn_ftrace *rec;
1705 bool update = false;
1709 /* Only update if the ops has been registered */
1710 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1714 * In the filter_hash case:
1715 * If the count is zero, we update all records.
1716 * Otherwise we just update the items in the hash.
1718 * In the notrace_hash case:
1719 * We enable the update in the hash.
1720 * As disabling notrace means enabling the tracing,
1721 * and enabling notrace means disabling, the inc variable
1725 hash = ops->func_hash->filter_hash;
1726 other_hash = ops->func_hash->notrace_hash;
1727 if (ftrace_hash_empty(hash))
1731 hash = ops->func_hash->notrace_hash;
1732 other_hash = ops->func_hash->filter_hash;
1734 * If the notrace hash has no items,
1735 * then there's nothing to do.
1737 if (ftrace_hash_empty(hash))
1741 do_for_each_ftrace_rec(pg, rec) {
1742 int in_other_hash = 0;
1746 if (skip_record(rec))
1751 * Only the filter_hash affects all records.
1752 * Update if the record is not in the notrace hash.
1754 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1757 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1758 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1761 * If filter_hash is set, we want to match all functions
1762 * that are in the hash but not in the other hash.
1764 * If filter_hash is not set, then we are decrementing.
1765 * That means we match anything that is in the hash
1766 * and also in the other_hash. That is, we need to turn
1767 * off functions in the other hash because they are disabled
1770 if (filter_hash && in_hash && !in_other_hash)
1772 else if (!filter_hash && in_hash &&
1773 (in_other_hash || ftrace_hash_empty(other_hash)))
1781 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1784 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1785 rec->flags |= FTRACE_FL_DIRECT;
1788 * If there's only a single callback registered to a
1789 * function, and the ops has a trampoline registered
1790 * for it, then we can call it directly.
1792 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1793 rec->flags |= FTRACE_FL_TRAMP;
1796 * If we are adding another function callback
1797 * to this function, and the previous had a
1798 * custom trampoline in use, then we need to go
1799 * back to the default trampoline.
1801 rec->flags &= ~FTRACE_FL_TRAMP;
1804 * If any ops wants regs saved for this function
1805 * then all ops will get saved regs.
1807 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1808 rec->flags |= FTRACE_FL_REGS;
1810 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1815 * Only the internal direct_ops should have the
1816 * DIRECT flag set. Thus, if it is removing a
1817 * function, then that function should no longer
1820 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1821 rec->flags &= ~FTRACE_FL_DIRECT;
1824 * If the rec had REGS enabled and the ops that is
1825 * being removed had REGS set, then see if there is
1826 * still any ops for this record that wants regs.
1827 * If not, we can stop recording them.
1829 if (ftrace_rec_count(rec) > 0 &&
1830 rec->flags & FTRACE_FL_REGS &&
1831 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1832 if (!test_rec_ops_needs_regs(rec))
1833 rec->flags &= ~FTRACE_FL_REGS;
1837 * The TRAMP needs to be set only if rec count
1838 * is decremented to one, and the ops that is
1839 * left has a trampoline. As TRAMP can only be
1840 * enabled if there is only a single ops attached
1843 if (ftrace_rec_count(rec) == 1 &&
1844 ftrace_find_tramp_ops_any_other(rec, ops))
1845 rec->flags |= FTRACE_FL_TRAMP;
1847 rec->flags &= ~FTRACE_FL_TRAMP;
1850 * flags will be cleared in ftrace_check_record()
1851 * if rec count is zero.
1856 * If the rec has a single associated ops, and ops->func can be
1857 * called directly, allow the call site to call via the ops.
1859 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1860 ftrace_rec_count(rec) == 1 &&
1861 ftrace_ops_get_func(ops) == ops->func)
1862 rec->flags |= FTRACE_FL_CALL_OPS;
1864 rec->flags &= ~FTRACE_FL_CALL_OPS;
1868 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1869 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1871 /* Shortcut, if we handled all records, we are done. */
1872 if (!all && count == hash->count)
1874 } while_for_each_ftrace_rec();
1879 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1882 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1885 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1888 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1891 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1892 int filter_hash, int inc)
1894 struct ftrace_ops *op;
1896 __ftrace_hash_rec_update(ops, filter_hash, inc);
1898 if (ops->func_hash != &global_ops.local_hash)
1902 * If the ops shares the global_ops hash, then we need to update
1903 * all ops that are enabled and use this hash.
1905 do_for_each_ftrace_op(op, ftrace_ops_list) {
1909 if (op->func_hash == &global_ops.local_hash)
1910 __ftrace_hash_rec_update(op, filter_hash, inc);
1911 } while_for_each_ftrace_op(op);
1914 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1917 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1920 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1923 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1927 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1928 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1929 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1930 * Note that old_hash and new_hash has below meanings
1931 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1932 * - If the hash is EMPTY_HASH, it hits nothing
1933 * - Anything else hits the recs which match the hash entries.
1935 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1936 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1937 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1938 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1939 * the return value to the caller and eventually to the owner of the DIRECT
1942 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1943 struct ftrace_hash *old_hash,
1944 struct ftrace_hash *new_hash)
1946 struct ftrace_page *pg;
1947 struct dyn_ftrace *rec, *end = NULL;
1949 bool is_ipmodify, is_direct;
1951 /* Only update if the ops has been registered */
1952 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1955 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1956 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1958 /* neither IPMODIFY nor DIRECT, skip */
1959 if (!is_ipmodify && !is_direct)
1962 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1966 * Since the IPMODIFY and DIRECT are very address sensitive
1967 * actions, we do not allow ftrace_ops to set all functions to new
1970 if (!new_hash || !old_hash)
1973 /* Update rec->flags */
1974 do_for_each_ftrace_rec(pg, rec) {
1976 if (rec->flags & FTRACE_FL_DISABLED)
1979 /* We need to update only differences of filter_hash */
1980 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1981 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1982 if (in_old == in_new)
1986 if (rec->flags & FTRACE_FL_IPMODIFY) {
1989 /* Cannot have two ipmodify on same rec */
1993 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1996 * Another ops with IPMODIFY is already
1997 * attached. We are now attaching a direct
1998 * ops. Run SHARE_IPMODIFY_SELF, to check
1999 * whether sharing is supported.
2003 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2006 } else if (is_ipmodify) {
2007 rec->flags |= FTRACE_FL_IPMODIFY;
2009 } else if (is_ipmodify) {
2010 rec->flags &= ~FTRACE_FL_IPMODIFY;
2012 } while_for_each_ftrace_rec();
2019 /* Roll back what we did above */
2020 do_for_each_ftrace_rec(pg, rec) {
2022 if (rec->flags & FTRACE_FL_DISABLED)
2028 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2029 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2030 if (in_old == in_new)
2034 rec->flags &= ~FTRACE_FL_IPMODIFY;
2036 rec->flags |= FTRACE_FL_IPMODIFY;
2037 } while_for_each_ftrace_rec();
2043 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2045 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2047 if (ftrace_hash_empty(hash))
2050 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2053 /* Disabling always succeeds */
2054 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2056 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2058 if (ftrace_hash_empty(hash))
2061 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2064 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2065 struct ftrace_hash *new_hash)
2067 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2069 if (ftrace_hash_empty(old_hash))
2072 if (ftrace_hash_empty(new_hash))
2075 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2078 static void print_ip_ins(const char *fmt, const unsigned char *p)
2080 char ins[MCOUNT_INSN_SIZE];
2082 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2083 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2087 printk(KERN_CONT "%s", fmt);
2088 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2091 enum ftrace_bug_type ftrace_bug_type;
2092 const void *ftrace_expected;
2094 static void print_bug_type(void)
2096 switch (ftrace_bug_type) {
2097 case FTRACE_BUG_UNKNOWN:
2099 case FTRACE_BUG_INIT:
2100 pr_info("Initializing ftrace call sites\n");
2102 case FTRACE_BUG_NOP:
2103 pr_info("Setting ftrace call site to NOP\n");
2105 case FTRACE_BUG_CALL:
2106 pr_info("Setting ftrace call site to call ftrace function\n");
2108 case FTRACE_BUG_UPDATE:
2109 pr_info("Updating ftrace call site to call a different ftrace function\n");
2115 * ftrace_bug - report and shutdown function tracer
2116 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2117 * @rec: The record that failed
2119 * The arch code that enables or disables the function tracing
2120 * can call ftrace_bug() when it has detected a problem in
2121 * modifying the code. @failed should be one of either:
2122 * EFAULT - if the problem happens on reading the @ip address
2123 * EINVAL - if what is read at @ip is not what was expected
2124 * EPERM - if the problem happens on writing to the @ip address
2126 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2128 unsigned long ip = rec ? rec->ip : 0;
2130 pr_info("------------[ ftrace bug ]------------\n");
2134 pr_info("ftrace faulted on modifying ");
2135 print_ip_sym(KERN_INFO, ip);
2138 pr_info("ftrace failed to modify ");
2139 print_ip_sym(KERN_INFO, ip);
2140 print_ip_ins(" actual: ", (unsigned char *)ip);
2142 if (ftrace_expected) {
2143 print_ip_ins(" expected: ", ftrace_expected);
2148 pr_info("ftrace faulted on writing ");
2149 print_ip_sym(KERN_INFO, ip);
2152 pr_info("ftrace faulted on unknown error ");
2153 print_ip_sym(KERN_INFO, ip);
2157 struct ftrace_ops *ops = NULL;
2159 pr_info("ftrace record flags: %lx\n", rec->flags);
2160 pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2161 rec->flags & FTRACE_FL_REGS ? " R" : " ",
2162 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ");
2163 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2164 ops = ftrace_find_tramp_ops_any(rec);
2167 pr_cont("\ttramp: %pS (%pS)",
2168 (void *)ops->trampoline,
2170 ops = ftrace_find_tramp_ops_next(rec, ops);
2173 pr_cont("\ttramp: ERROR!");
2176 ip = ftrace_get_addr_curr(rec);
2177 pr_cont("\n expected tramp: %lx\n", ip);
2180 FTRACE_WARN_ON_ONCE(1);
2183 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2185 unsigned long flag = 0UL;
2187 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2189 if (skip_record(rec))
2190 return FTRACE_UPDATE_IGNORE;
2193 * If we are updating calls:
2195 * If the record has a ref count, then we need to enable it
2196 * because someone is using it.
2198 * Otherwise we make sure its disabled.
2200 * If we are disabling calls, then disable all records that
2203 if (enable && ftrace_rec_count(rec))
2204 flag = FTRACE_FL_ENABLED;
2207 * If enabling and the REGS flag does not match the REGS_EN, or
2208 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2209 * this record. Set flags to fail the compare against ENABLED.
2210 * Same for direct calls.
2213 if (!(rec->flags & FTRACE_FL_REGS) !=
2214 !(rec->flags & FTRACE_FL_REGS_EN))
2215 flag |= FTRACE_FL_REGS;
2217 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2218 !(rec->flags & FTRACE_FL_TRAMP_EN))
2219 flag |= FTRACE_FL_TRAMP;
2222 * Direct calls are special, as count matters.
2223 * We must test the record for direct, if the
2224 * DIRECT and DIRECT_EN do not match, but only
2225 * if the count is 1. That's because, if the
2226 * count is something other than one, we do not
2227 * want the direct enabled (it will be done via the
2228 * direct helper). But if DIRECT_EN is set, and
2229 * the count is not one, we need to clear it.
2232 if (ftrace_rec_count(rec) == 1) {
2233 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2234 !(rec->flags & FTRACE_FL_DIRECT_EN))
2235 flag |= FTRACE_FL_DIRECT;
2236 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2237 flag |= FTRACE_FL_DIRECT;
2241 * Ops calls are special, as count matters.
2242 * As with direct calls, they must only be enabled when count
2243 * is one, otherwise they'll be handled via the list ops.
2245 if (ftrace_rec_count(rec) == 1) {
2246 if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2247 !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2248 flag |= FTRACE_FL_CALL_OPS;
2249 } else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2250 flag |= FTRACE_FL_CALL_OPS;
2254 /* If the state of this record hasn't changed, then do nothing */
2255 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2256 return FTRACE_UPDATE_IGNORE;
2259 /* Save off if rec is being enabled (for return value) */
2260 flag ^= rec->flags & FTRACE_FL_ENABLED;
2263 rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2264 if (flag & FTRACE_FL_REGS) {
2265 if (rec->flags & FTRACE_FL_REGS)
2266 rec->flags |= FTRACE_FL_REGS_EN;
2268 rec->flags &= ~FTRACE_FL_REGS_EN;
2270 if (flag & FTRACE_FL_TRAMP) {
2271 if (rec->flags & FTRACE_FL_TRAMP)
2272 rec->flags |= FTRACE_FL_TRAMP_EN;
2274 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2277 /* Keep track of anything that modifies the function */
2278 if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2279 rec->flags |= FTRACE_FL_MODIFIED;
2281 if (flag & FTRACE_FL_DIRECT) {
2283 * If there's only one user (direct_ops helper)
2284 * then we can call the direct function
2285 * directly (no ftrace trampoline).
2287 if (ftrace_rec_count(rec) == 1) {
2288 if (rec->flags & FTRACE_FL_DIRECT)
2289 rec->flags |= FTRACE_FL_DIRECT_EN;
2291 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2294 * Can only call directly if there's
2295 * only one callback to the function.
2297 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2301 if (flag & FTRACE_FL_CALL_OPS) {
2302 if (ftrace_rec_count(rec) == 1) {
2303 if (rec->flags & FTRACE_FL_CALL_OPS)
2304 rec->flags |= FTRACE_FL_CALL_OPS_EN;
2306 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2309 * Can only call directly if there's
2310 * only one set of associated ops.
2312 rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2318 * If this record is being updated from a nop, then
2319 * return UPDATE_MAKE_CALL.
2321 * return UPDATE_MODIFY_CALL to tell the caller to convert
2322 * from the save regs, to a non-save regs function or
2323 * vice versa, or from a trampoline call.
2325 if (flag & FTRACE_FL_ENABLED) {
2326 ftrace_bug_type = FTRACE_BUG_CALL;
2327 return FTRACE_UPDATE_MAKE_CALL;
2330 ftrace_bug_type = FTRACE_BUG_UPDATE;
2331 return FTRACE_UPDATE_MODIFY_CALL;
2335 /* If there's no more users, clear all flags */
2336 if (!ftrace_rec_count(rec))
2337 rec->flags &= FTRACE_NOCLEAR_FLAGS;
2340 * Just disable the record, but keep the ops TRAMP
2341 * and REGS states. The _EN flags must be disabled though.
2343 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2344 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2345 FTRACE_FL_CALL_OPS_EN);
2348 ftrace_bug_type = FTRACE_BUG_NOP;
2349 return FTRACE_UPDATE_MAKE_NOP;
2353 * ftrace_update_record - set a record that now is tracing or not
2354 * @rec: the record to update
2355 * @enable: set to true if the record is tracing, false to force disable
2357 * The records that represent all functions that can be traced need
2358 * to be updated when tracing has been enabled.
2360 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2362 return ftrace_check_record(rec, enable, true);
2366 * ftrace_test_record - check if the record has been enabled or not
2367 * @rec: the record to test
2368 * @enable: set to true to check if enabled, false if it is disabled
2370 * The arch code may need to test if a record is already set to
2371 * tracing to determine how to modify the function code that it
2374 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2376 return ftrace_check_record(rec, enable, false);
2379 static struct ftrace_ops *
2380 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2382 struct ftrace_ops *op;
2383 unsigned long ip = rec->ip;
2385 do_for_each_ftrace_op(op, ftrace_ops_list) {
2387 if (!op->trampoline)
2390 if (hash_contains_ip(ip, op->func_hash))
2392 } while_for_each_ftrace_op(op);
2397 static struct ftrace_ops *
2398 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2400 struct ftrace_ops *op;
2401 unsigned long ip = rec->ip;
2403 do_for_each_ftrace_op(op, ftrace_ops_list) {
2405 if (op == op_exclude || !op->trampoline)
2408 if (hash_contains_ip(ip, op->func_hash))
2410 } while_for_each_ftrace_op(op);
2415 static struct ftrace_ops *
2416 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2417 struct ftrace_ops *op)
2419 unsigned long ip = rec->ip;
2421 while_for_each_ftrace_op(op) {
2423 if (!op->trampoline)
2426 if (hash_contains_ip(ip, op->func_hash))
2433 static struct ftrace_ops *
2434 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2436 struct ftrace_ops *op;
2437 unsigned long ip = rec->ip;
2440 * Need to check removed ops first.
2441 * If they are being removed, and this rec has a tramp,
2442 * and this rec is in the ops list, then it would be the
2443 * one with the tramp.
2446 if (hash_contains_ip(ip, &removed_ops->old_hash))
2451 * Need to find the current trampoline for a rec.
2452 * Now, a trampoline is only attached to a rec if there
2453 * was a single 'ops' attached to it. But this can be called
2454 * when we are adding another op to the rec or removing the
2455 * current one. Thus, if the op is being added, we can
2456 * ignore it because it hasn't attached itself to the rec
2459 * If an ops is being modified (hooking to different functions)
2460 * then we don't care about the new functions that are being
2461 * added, just the old ones (that are probably being removed).
2463 * If we are adding an ops to a function that already is using
2464 * a trampoline, it needs to be removed (trampolines are only
2465 * for single ops connected), then an ops that is not being
2466 * modified also needs to be checked.
2468 do_for_each_ftrace_op(op, ftrace_ops_list) {
2470 if (!op->trampoline)
2474 * If the ops is being added, it hasn't gotten to
2475 * the point to be removed from this tree yet.
2477 if (op->flags & FTRACE_OPS_FL_ADDING)
2482 * If the ops is being modified and is in the old
2483 * hash, then it is probably being removed from this
2486 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2487 hash_contains_ip(ip, &op->old_hash))
2490 * If the ops is not being added or modified, and it's
2491 * in its normal filter hash, then this must be the one
2494 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2495 hash_contains_ip(ip, op->func_hash))
2498 } while_for_each_ftrace_op(op);
2503 static struct ftrace_ops *
2504 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2506 struct ftrace_ops *op;
2507 unsigned long ip = rec->ip;
2509 do_for_each_ftrace_op(op, ftrace_ops_list) {
2510 /* pass rec in as regs to have non-NULL val */
2511 if (hash_contains_ip(ip, op->func_hash))
2513 } while_for_each_ftrace_op(op);
2519 ftrace_find_unique_ops(struct dyn_ftrace *rec)
2521 struct ftrace_ops *op, *found = NULL;
2522 unsigned long ip = rec->ip;
2524 do_for_each_ftrace_op(op, ftrace_ops_list) {
2526 if (hash_contains_ip(ip, op->func_hash)) {
2532 } while_for_each_ftrace_op(op);
2537 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2538 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2539 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2540 static DEFINE_MUTEX(direct_mutex);
2541 int ftrace_direct_func_count;
2544 * Search the direct_functions hash to see if the given instruction pointer
2545 * has a direct caller attached to it.
2547 unsigned long ftrace_find_rec_direct(unsigned long ip)
2549 struct ftrace_func_entry *entry;
2551 entry = __ftrace_lookup_ip(direct_functions, ip);
2555 return entry->direct;
2558 static struct ftrace_func_entry*
2559 ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
2560 struct ftrace_hash **free_hash)
2562 struct ftrace_func_entry *entry;
2564 if (ftrace_hash_empty(direct_functions) ||
2565 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
2566 struct ftrace_hash *new_hash;
2567 int size = ftrace_hash_empty(direct_functions) ? 0 :
2568 direct_functions->count + 1;
2573 new_hash = dup_hash(direct_functions, size);
2577 *free_hash = direct_functions;
2578 direct_functions = new_hash;
2581 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2586 entry->direct = addr;
2587 __add_hash_entry(direct_functions, entry);
2591 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2592 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2594 unsigned long addr = READ_ONCE(ops->direct_call);
2599 arch_ftrace_set_direct_caller(fregs, addr);
2601 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2604 * ftrace_get_addr_new - Get the call address to set to
2605 * @rec: The ftrace record descriptor
2607 * If the record has the FTRACE_FL_REGS set, that means that it
2608 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2609 * is not set, then it wants to convert to the normal callback.
2611 * Returns the address of the trampoline to set to
2613 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2615 struct ftrace_ops *ops;
2618 if ((rec->flags & FTRACE_FL_DIRECT) &&
2619 (ftrace_rec_count(rec) == 1)) {
2620 addr = ftrace_find_rec_direct(rec->ip);
2626 /* Trampolines take precedence over regs */
2627 if (rec->flags & FTRACE_FL_TRAMP) {
2628 ops = ftrace_find_tramp_ops_new(rec);
2629 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2630 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2631 (void *)rec->ip, (void *)rec->ip, rec->flags);
2632 /* Ftrace is shutting down, return anything */
2633 return (unsigned long)FTRACE_ADDR;
2635 return ops->trampoline;
2638 if (rec->flags & FTRACE_FL_REGS)
2639 return (unsigned long)FTRACE_REGS_ADDR;
2641 return (unsigned long)FTRACE_ADDR;
2645 * ftrace_get_addr_curr - Get the call address that is already there
2646 * @rec: The ftrace record descriptor
2648 * The FTRACE_FL_REGS_EN is set when the record already points to
2649 * a function that saves all the regs. Basically the '_EN' version
2650 * represents the current state of the function.
2652 * Returns the address of the trampoline that is currently being called
2654 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2656 struct ftrace_ops *ops;
2659 /* Direct calls take precedence over trampolines */
2660 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2661 addr = ftrace_find_rec_direct(rec->ip);
2667 /* Trampolines take precedence over regs */
2668 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2669 ops = ftrace_find_tramp_ops_curr(rec);
2670 if (FTRACE_WARN_ON(!ops)) {
2671 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2672 (void *)rec->ip, (void *)rec->ip);
2673 /* Ftrace is shutting down, return anything */
2674 return (unsigned long)FTRACE_ADDR;
2676 return ops->trampoline;
2679 if (rec->flags & FTRACE_FL_REGS_EN)
2680 return (unsigned long)FTRACE_REGS_ADDR;
2682 return (unsigned long)FTRACE_ADDR;
2686 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2688 unsigned long ftrace_old_addr;
2689 unsigned long ftrace_addr;
2692 ftrace_addr = ftrace_get_addr_new(rec);
2694 /* This needs to be done before we call ftrace_update_record */
2695 ftrace_old_addr = ftrace_get_addr_curr(rec);
2697 ret = ftrace_update_record(rec, enable);
2699 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2702 case FTRACE_UPDATE_IGNORE:
2705 case FTRACE_UPDATE_MAKE_CALL:
2706 ftrace_bug_type = FTRACE_BUG_CALL;
2707 return ftrace_make_call(rec, ftrace_addr);
2709 case FTRACE_UPDATE_MAKE_NOP:
2710 ftrace_bug_type = FTRACE_BUG_NOP;
2711 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2713 case FTRACE_UPDATE_MODIFY_CALL:
2714 ftrace_bug_type = FTRACE_BUG_UPDATE;
2715 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2718 return -1; /* unknown ftrace bug */
2721 void __weak ftrace_replace_code(int mod_flags)
2723 struct dyn_ftrace *rec;
2724 struct ftrace_page *pg;
2725 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2726 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2729 if (unlikely(ftrace_disabled))
2732 do_for_each_ftrace_rec(pg, rec) {
2734 if (skip_record(rec))
2737 failed = __ftrace_replace_code(rec, enable);
2739 ftrace_bug(failed, rec);
2740 /* Stop processing */
2745 } while_for_each_ftrace_rec();
2748 struct ftrace_rec_iter {
2749 struct ftrace_page *pg;
2754 * ftrace_rec_iter_start - start up iterating over traced functions
2756 * Returns an iterator handle that is used to iterate over all
2757 * the records that represent address locations where functions
2760 * May return NULL if no records are available.
2762 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2765 * We only use a single iterator.
2766 * Protected by the ftrace_lock mutex.
2768 static struct ftrace_rec_iter ftrace_rec_iter;
2769 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2771 iter->pg = ftrace_pages_start;
2774 /* Could have empty pages */
2775 while (iter->pg && !iter->pg->index)
2776 iter->pg = iter->pg->next;
2785 * ftrace_rec_iter_next - get the next record to process.
2786 * @iter: The handle to the iterator.
2788 * Returns the next iterator after the given iterator @iter.
2790 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2794 if (iter->index >= iter->pg->index) {
2795 iter->pg = iter->pg->next;
2798 /* Could have empty pages */
2799 while (iter->pg && !iter->pg->index)
2800 iter->pg = iter->pg->next;
2810 * ftrace_rec_iter_record - get the record at the iterator location
2811 * @iter: The current iterator location
2813 * Returns the record that the current @iter is at.
2815 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2817 return &iter->pg->records[iter->index];
2821 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2825 if (unlikely(ftrace_disabled))
2828 ret = ftrace_init_nop(mod, rec);
2830 ftrace_bug_type = FTRACE_BUG_INIT;
2831 ftrace_bug(ret, rec);
2838 * archs can override this function if they must do something
2839 * before the modifying code is performed.
2841 void __weak ftrace_arch_code_modify_prepare(void)
2846 * archs can override this function if they must do something
2847 * after the modifying code is performed.
2849 void __weak ftrace_arch_code_modify_post_process(void)
2853 static int update_ftrace_func(ftrace_func_t func)
2855 static ftrace_func_t save_func;
2857 /* Avoid updating if it hasn't changed */
2858 if (func == save_func)
2863 return ftrace_update_ftrace_func(func);
2866 void ftrace_modify_all_code(int command)
2868 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2872 if (command & FTRACE_MAY_SLEEP)
2873 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2876 * If the ftrace_caller calls a ftrace_ops func directly,
2877 * we need to make sure that it only traces functions it
2878 * expects to trace. When doing the switch of functions,
2879 * we need to update to the ftrace_ops_list_func first
2880 * before the transition between old and new calls are set,
2881 * as the ftrace_ops_list_func will check the ops hashes
2882 * to make sure the ops are having the right functions
2886 err = update_ftrace_func(ftrace_ops_list_func);
2887 if (FTRACE_WARN_ON(err))
2891 if (command & FTRACE_UPDATE_CALLS)
2892 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2893 else if (command & FTRACE_DISABLE_CALLS)
2894 ftrace_replace_code(mod_flags);
2896 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2897 function_trace_op = set_function_trace_op;
2899 /* If irqs are disabled, we are in stop machine */
2900 if (!irqs_disabled())
2901 smp_call_function(ftrace_sync_ipi, NULL, 1);
2902 err = update_ftrace_func(ftrace_trace_function);
2903 if (FTRACE_WARN_ON(err))
2907 if (command & FTRACE_START_FUNC_RET)
2908 err = ftrace_enable_ftrace_graph_caller();
2909 else if (command & FTRACE_STOP_FUNC_RET)
2910 err = ftrace_disable_ftrace_graph_caller();
2911 FTRACE_WARN_ON(err);
2914 static int __ftrace_modify_code(void *data)
2916 int *command = data;
2918 ftrace_modify_all_code(*command);
2924 * ftrace_run_stop_machine - go back to the stop machine method
2925 * @command: The command to tell ftrace what to do
2927 * If an arch needs to fall back to the stop machine method, the
2928 * it can call this function.
2930 void ftrace_run_stop_machine(int command)
2932 stop_machine(__ftrace_modify_code, &command, NULL);
2936 * arch_ftrace_update_code - modify the code to trace or not trace
2937 * @command: The command that needs to be done
2939 * Archs can override this function if it does not need to
2940 * run stop_machine() to modify code.
2942 void __weak arch_ftrace_update_code(int command)
2944 ftrace_run_stop_machine(command);
2947 static void ftrace_run_update_code(int command)
2949 ftrace_arch_code_modify_prepare();
2952 * By default we use stop_machine() to modify the code.
2953 * But archs can do what ever they want as long as it
2954 * is safe. The stop_machine() is the safest, but also
2955 * produces the most overhead.
2957 arch_ftrace_update_code(command);
2959 ftrace_arch_code_modify_post_process();
2962 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2963 struct ftrace_ops_hash *old_hash)
2965 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2966 ops->old_hash.filter_hash = old_hash->filter_hash;
2967 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2968 ftrace_run_update_code(command);
2969 ops->old_hash.filter_hash = NULL;
2970 ops->old_hash.notrace_hash = NULL;
2971 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2974 static ftrace_func_t saved_ftrace_func;
2975 static int ftrace_start_up;
2977 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2981 /* List of trace_ops that have allocated trampolines */
2982 static LIST_HEAD(ftrace_ops_trampoline_list);
2984 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2986 lockdep_assert_held(&ftrace_lock);
2987 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2990 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2992 lockdep_assert_held(&ftrace_lock);
2993 list_del_rcu(&ops->list);
2998 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2999 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
3002 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
3003 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
3005 static void ftrace_trampoline_free(struct ftrace_ops *ops)
3007 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
3010 * Record the text poke event before the ksymbol unregister
3013 perf_event_text_poke((void *)ops->trampoline,
3014 (void *)ops->trampoline,
3015 ops->trampoline_size, NULL, 0);
3016 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
3017 ops->trampoline, ops->trampoline_size,
3018 true, FTRACE_TRAMPOLINE_SYM);
3019 /* Remove from kallsyms after the perf events */
3020 ftrace_remove_trampoline_from_kallsyms(ops);
3023 arch_ftrace_trampoline_free(ops);
3026 static void ftrace_startup_enable(int command)
3028 if (saved_ftrace_func != ftrace_trace_function) {
3029 saved_ftrace_func = ftrace_trace_function;
3030 command |= FTRACE_UPDATE_TRACE_FUNC;
3033 if (!command || !ftrace_enabled)
3036 ftrace_run_update_code(command);
3039 static void ftrace_startup_all(int command)
3041 update_all_ops = true;
3042 ftrace_startup_enable(command);
3043 update_all_ops = false;
3046 int ftrace_startup(struct ftrace_ops *ops, int command)
3050 if (unlikely(ftrace_disabled))
3053 ret = __register_ftrace_function(ops);
3060 * Note that ftrace probes uses this to start up
3061 * and modify functions it will probe. But we still
3062 * set the ADDING flag for modification, as probes
3063 * do not have trampolines. If they add them in the
3064 * future, then the probes will need to distinguish
3065 * between adding and updating probes.
3067 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3069 ret = ftrace_hash_ipmodify_enable(ops);
3071 /* Rollback registration process */
3072 __unregister_ftrace_function(ops);
3074 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3075 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3076 ftrace_trampoline_free(ops);
3080 if (ftrace_hash_rec_enable(ops, 1))
3081 command |= FTRACE_UPDATE_CALLS;
3083 ftrace_startup_enable(command);
3086 * If ftrace is in an undefined state, we just remove ops from list
3087 * to prevent the NULL pointer, instead of totally rolling it back and
3088 * free trampoline, because those actions could cause further damage.
3090 if (unlikely(ftrace_disabled)) {
3091 __unregister_ftrace_function(ops);
3095 ops->flags &= ~FTRACE_OPS_FL_ADDING;
3100 int ftrace_shutdown(struct ftrace_ops *ops, int command)
3104 if (unlikely(ftrace_disabled))
3107 ret = __unregister_ftrace_function(ops);
3113 * Just warn in case of unbalance, no need to kill ftrace, it's not
3114 * critical but the ftrace_call callers may be never nopped again after
3115 * further ftrace uses.
3117 WARN_ON_ONCE(ftrace_start_up < 0);
3119 /* Disabling ipmodify never fails */
3120 ftrace_hash_ipmodify_disable(ops);
3122 if (ftrace_hash_rec_disable(ops, 1))
3123 command |= FTRACE_UPDATE_CALLS;
3125 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3127 if (saved_ftrace_func != ftrace_trace_function) {
3128 saved_ftrace_func = ftrace_trace_function;
3129 command |= FTRACE_UPDATE_TRACE_FUNC;
3132 if (!command || !ftrace_enabled)
3136 * If the ops uses a trampoline, then it needs to be
3137 * tested first on update.
3139 ops->flags |= FTRACE_OPS_FL_REMOVING;
3142 /* The trampoline logic checks the old hashes */
3143 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3144 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3146 ftrace_run_update_code(command);
3149 * If there's no more ops registered with ftrace, run a
3150 * sanity check to make sure all rec flags are cleared.
3152 if (rcu_dereference_protected(ftrace_ops_list,
3153 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3154 struct ftrace_page *pg;
3155 struct dyn_ftrace *rec;
3157 do_for_each_ftrace_rec(pg, rec) {
3158 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3159 pr_warn(" %pS flags:%lx\n",
3160 (void *)rec->ip, rec->flags);
3161 } while_for_each_ftrace_rec();
3164 ops->old_hash.filter_hash = NULL;
3165 ops->old_hash.notrace_hash = NULL;
3168 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3172 * Dynamic ops may be freed, we must make sure that all
3173 * callers are done before leaving this function.
3175 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3177 * We need to do a hard force of sched synchronization.
3178 * This is because we use preempt_disable() to do RCU, but
3179 * the function tracers can be called where RCU is not watching
3180 * (like before user_exit()). We can not rely on the RCU
3181 * infrastructure to do the synchronization, thus we must do it
3184 synchronize_rcu_tasks_rude();
3187 * When the kernel is preemptive, tasks can be preempted
3188 * while on a ftrace trampoline. Just scheduling a task on
3189 * a CPU is not good enough to flush them. Calling
3190 * synchronize_rcu_tasks() will wait for those tasks to
3191 * execute and either schedule voluntarily or enter user space.
3193 if (IS_ENABLED(CONFIG_PREEMPTION))
3194 synchronize_rcu_tasks();
3196 ftrace_trampoline_free(ops);
3202 static u64 ftrace_update_time;
3203 unsigned long ftrace_update_tot_cnt;
3204 unsigned long ftrace_number_of_pages;
3205 unsigned long ftrace_number_of_groups;
3207 static inline int ops_traces_mod(struct ftrace_ops *ops)
3210 * Filter_hash being empty will default to trace module.
3211 * But notrace hash requires a test of individual module functions.
3213 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3214 ftrace_hash_empty(ops->func_hash->notrace_hash);
3217 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3219 bool init_nop = ftrace_need_init_nop();
3220 struct ftrace_page *pg;
3221 struct dyn_ftrace *p;
3223 unsigned long update_cnt = 0;
3224 unsigned long rec_flags = 0;
3227 start = ftrace_now(raw_smp_processor_id());
3230 * When a module is loaded, this function is called to convert
3231 * the calls to mcount in its text to nops, and also to create
3232 * an entry in the ftrace data. Now, if ftrace is activated
3233 * after this call, but before the module sets its text to
3234 * read-only, the modification of enabling ftrace can fail if
3235 * the read-only is done while ftrace is converting the calls.
3236 * To prevent this, the module's records are set as disabled
3237 * and will be enabled after the call to set the module's text
3241 rec_flags |= FTRACE_FL_DISABLED;
3243 for (pg = new_pgs; pg; pg = pg->next) {
3245 for (i = 0; i < pg->index; i++) {
3247 /* If something went wrong, bail without enabling anything */
3248 if (unlikely(ftrace_disabled))
3251 p = &pg->records[i];
3252 p->flags = rec_flags;
3255 * Do the initial record conversion from mcount jump
3256 * to the NOP instructions.
3258 if (init_nop && !ftrace_nop_initialize(mod, p))
3265 stop = ftrace_now(raw_smp_processor_id());
3266 ftrace_update_time = stop - start;
3267 ftrace_update_tot_cnt += update_cnt;
3272 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3278 if (WARN_ON(!count))
3281 /* We want to fill as much as possible, with no empty pages */
3282 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3283 order = fls(pages) - 1;
3286 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3289 /* if we can't allocate this size, try something smaller */
3296 ftrace_number_of_pages += 1 << order;
3297 ftrace_number_of_groups++;
3299 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3308 static struct ftrace_page *
3309 ftrace_allocate_pages(unsigned long num_to_init)
3311 struct ftrace_page *start_pg;
3312 struct ftrace_page *pg;
3318 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3323 * Try to allocate as much as possible in one continues
3324 * location that fills in all of the space. We want to
3325 * waste as little space as possible.
3328 cnt = ftrace_allocate_records(pg, num_to_init);
3336 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3349 free_pages((unsigned long)pg->records, pg->order);
3350 ftrace_number_of_pages -= 1 << pg->order;
3352 start_pg = pg->next;
3355 ftrace_number_of_groups--;
3357 pr_info("ftrace: FAILED to allocate memory for functions\n");
3361 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3363 struct ftrace_iterator {
3367 struct ftrace_page *pg;
3368 struct dyn_ftrace *func;
3369 struct ftrace_func_probe *probe;
3370 struct ftrace_func_entry *probe_entry;
3371 struct trace_parser parser;
3372 struct ftrace_hash *hash;
3373 struct ftrace_ops *ops;
3374 struct trace_array *tr;
3375 struct list_head *mod_list;
3382 t_probe_next(struct seq_file *m, loff_t *pos)
3384 struct ftrace_iterator *iter = m->private;
3385 struct trace_array *tr = iter->ops->private;
3386 struct list_head *func_probes;
3387 struct ftrace_hash *hash;
3388 struct list_head *next;
3389 struct hlist_node *hnd = NULL;
3390 struct hlist_head *hhd;
3399 func_probes = &tr->func_probes;
3400 if (list_empty(func_probes))
3404 next = func_probes->next;
3405 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3408 if (iter->probe_entry)
3409 hnd = &iter->probe_entry->hlist;
3411 hash = iter->probe->ops.func_hash->filter_hash;
3414 * A probe being registered may temporarily have an empty hash
3415 * and it's at the end of the func_probes list.
3417 if (!hash || hash == EMPTY_HASH)
3420 size = 1 << hash->size_bits;
3423 if (iter->pidx >= size) {
3424 if (iter->probe->list.next == func_probes)
3426 next = iter->probe->list.next;
3427 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3428 hash = iter->probe->ops.func_hash->filter_hash;
3429 size = 1 << hash->size_bits;
3433 hhd = &hash->buckets[iter->pidx];
3435 if (hlist_empty(hhd)) {
3451 if (WARN_ON_ONCE(!hnd))
3454 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3459 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3461 struct ftrace_iterator *iter = m->private;
3465 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3468 if (iter->mod_pos > *pos)
3472 iter->probe_entry = NULL;
3474 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3475 p = t_probe_next(m, &l);
3482 /* Only set this if we have an item */
3483 iter->flags |= FTRACE_ITER_PROBE;
3489 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3491 struct ftrace_func_entry *probe_entry;
3492 struct ftrace_probe_ops *probe_ops;
3493 struct ftrace_func_probe *probe;
3495 probe = iter->probe;
3496 probe_entry = iter->probe_entry;
3498 if (WARN_ON_ONCE(!probe || !probe_entry))
3501 probe_ops = probe->probe_ops;
3503 if (probe_ops->print)
3504 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3506 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3507 (void *)probe_ops->func);
3513 t_mod_next(struct seq_file *m, loff_t *pos)
3515 struct ftrace_iterator *iter = m->private;
3516 struct trace_array *tr = iter->tr;
3521 iter->mod_list = iter->mod_list->next;
3523 if (iter->mod_list == &tr->mod_trace ||
3524 iter->mod_list == &tr->mod_notrace) {
3525 iter->flags &= ~FTRACE_ITER_MOD;
3529 iter->mod_pos = *pos;
3534 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3536 struct ftrace_iterator *iter = m->private;
3540 if (iter->func_pos > *pos)
3543 iter->mod_pos = iter->func_pos;
3545 /* probes are only available if tr is set */
3549 for (l = 0; l <= (*pos - iter->func_pos); ) {
3550 p = t_mod_next(m, &l);
3555 iter->flags &= ~FTRACE_ITER_MOD;
3556 return t_probe_start(m, pos);
3559 /* Only set this if we have an item */
3560 iter->flags |= FTRACE_ITER_MOD;
3566 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3568 struct ftrace_mod_load *ftrace_mod;
3569 struct trace_array *tr = iter->tr;
3571 if (WARN_ON_ONCE(!iter->mod_list) ||
3572 iter->mod_list == &tr->mod_trace ||
3573 iter->mod_list == &tr->mod_notrace)
3576 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3578 if (ftrace_mod->func)
3579 seq_printf(m, "%s", ftrace_mod->func);
3583 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3589 t_func_next(struct seq_file *m, loff_t *pos)
3591 struct ftrace_iterator *iter = m->private;
3592 struct dyn_ftrace *rec = NULL;
3597 if (iter->idx >= iter->pg->index) {
3598 if (iter->pg->next) {
3599 iter->pg = iter->pg->next;
3604 rec = &iter->pg->records[iter->idx++];
3605 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3606 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3608 ((iter->flags & FTRACE_ITER_ENABLED) &&
3609 !(rec->flags & FTRACE_FL_ENABLED)) ||
3611 ((iter->flags & FTRACE_ITER_TOUCHED) &&
3612 !(rec->flags & FTRACE_FL_TOUCHED))) {
3622 iter->pos = iter->func_pos = *pos;
3629 t_next(struct seq_file *m, void *v, loff_t *pos)
3631 struct ftrace_iterator *iter = m->private;
3632 loff_t l = *pos; /* t_probe_start() must use original pos */
3635 if (unlikely(ftrace_disabled))
3638 if (iter->flags & FTRACE_ITER_PROBE)
3639 return t_probe_next(m, pos);
3641 if (iter->flags & FTRACE_ITER_MOD)
3642 return t_mod_next(m, pos);
3644 if (iter->flags & FTRACE_ITER_PRINTALL) {
3645 /* next must increment pos, and t_probe_start does not */
3647 return t_mod_start(m, &l);
3650 ret = t_func_next(m, pos);
3653 return t_mod_start(m, &l);
3658 static void reset_iter_read(struct ftrace_iterator *iter)
3662 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3665 static void *t_start(struct seq_file *m, loff_t *pos)
3667 struct ftrace_iterator *iter = m->private;
3671 mutex_lock(&ftrace_lock);
3673 if (unlikely(ftrace_disabled))
3677 * If an lseek was done, then reset and start from beginning.
3679 if (*pos < iter->pos)
3680 reset_iter_read(iter);
3683 * For set_ftrace_filter reading, if we have the filter
3684 * off, we can short cut and just print out that all
3685 * functions are enabled.
3687 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3688 ftrace_hash_empty(iter->hash)) {
3689 iter->func_pos = 1; /* Account for the message */
3691 return t_mod_start(m, pos);
3692 iter->flags |= FTRACE_ITER_PRINTALL;
3693 /* reset in case of seek/pread */
3694 iter->flags &= ~FTRACE_ITER_PROBE;
3698 if (iter->flags & FTRACE_ITER_MOD)
3699 return t_mod_start(m, pos);
3702 * Unfortunately, we need to restart at ftrace_pages_start
3703 * every time we let go of the ftrace_mutex. This is because
3704 * those pointers can change without the lock.
3706 iter->pg = ftrace_pages_start;
3708 for (l = 0; l <= *pos; ) {
3709 p = t_func_next(m, &l);
3715 return t_mod_start(m, pos);
3720 static void t_stop(struct seq_file *m, void *p)
3722 mutex_unlock(&ftrace_lock);
3726 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3731 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3732 struct dyn_ftrace *rec)
3736 ptr = arch_ftrace_trampoline_func(ops, rec);
3738 seq_printf(m, " ->%pS", ptr);
3741 #ifdef FTRACE_MCOUNT_MAX_OFFSET
3743 * Weak functions can still have an mcount/fentry that is saved in
3744 * the __mcount_loc section. These can be detected by having a
3745 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3746 * symbol found by kallsyms is not the function that the mcount/fentry
3747 * is part of. The offset is much greater in these cases.
3749 * Test the record to make sure that the ip points to a valid kallsyms
3750 * and if not, mark it disabled.
3752 static int test_for_valid_rec(struct dyn_ftrace *rec)
3754 char str[KSYM_SYMBOL_LEN];
3755 unsigned long offset;
3758 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3760 /* Weak functions can cause invalid addresses */
3761 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3762 rec->flags |= FTRACE_FL_DISABLED;
3768 static struct workqueue_struct *ftrace_check_wq __initdata;
3769 static struct work_struct ftrace_check_work __initdata;
3772 * Scan all the mcount/fentry entries to make sure they are valid.
3774 static __init void ftrace_check_work_func(struct work_struct *work)
3776 struct ftrace_page *pg;
3777 struct dyn_ftrace *rec;
3779 mutex_lock(&ftrace_lock);
3780 do_for_each_ftrace_rec(pg, rec) {
3781 test_for_valid_rec(rec);
3782 } while_for_each_ftrace_rec();
3783 mutex_unlock(&ftrace_lock);
3786 static int __init ftrace_check_for_weak_functions(void)
3788 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3790 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3792 queue_work(ftrace_check_wq, &ftrace_check_work);
3796 static int __init ftrace_check_sync(void)
3798 /* Make sure the ftrace_check updates are finished */
3799 if (ftrace_check_wq)
3800 destroy_workqueue(ftrace_check_wq);
3804 late_initcall_sync(ftrace_check_sync);
3805 subsys_initcall(ftrace_check_for_weak_functions);
3807 static int print_rec(struct seq_file *m, unsigned long ip)
3809 unsigned long offset;
3810 char str[KSYM_SYMBOL_LEN];
3814 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3815 /* Weak functions can cause invalid addresses */
3816 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3817 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3818 FTRACE_INVALID_FUNCTION, offset);
3824 seq_printf(m, " [%s]", modname);
3825 return ret == NULL ? -1 : 0;
3828 static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3833 static inline int print_rec(struct seq_file *m, unsigned long ip)
3835 seq_printf(m, "%ps", (void *)ip);
3840 static int t_show(struct seq_file *m, void *v)
3842 struct ftrace_iterator *iter = m->private;
3843 struct dyn_ftrace *rec;
3845 if (iter->flags & FTRACE_ITER_PROBE)
3846 return t_probe_show(m, iter);
3848 if (iter->flags & FTRACE_ITER_MOD)
3849 return t_mod_show(m, iter);
3851 if (iter->flags & FTRACE_ITER_PRINTALL) {
3852 if (iter->flags & FTRACE_ITER_NOTRACE)
3853 seq_puts(m, "#### no functions disabled ####\n");
3855 seq_puts(m, "#### all functions enabled ####\n");
3864 if (print_rec(m, rec->ip)) {
3865 /* This should only happen when a rec is disabled */
3866 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3871 if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3872 struct ftrace_ops *ops;
3874 seq_printf(m, " (%ld)%s%s%s%s%s",
3875 ftrace_rec_count(rec),
3876 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3877 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3878 rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
3879 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
3880 rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
3881 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3882 ops = ftrace_find_tramp_ops_any(rec);
3885 seq_printf(m, "\ttramp: %pS (%pS)",
3886 (void *)ops->trampoline,
3888 add_trampoline_func(m, ops, rec);
3889 ops = ftrace_find_tramp_ops_next(rec, ops);
3892 seq_puts(m, "\ttramp: ERROR!");
3894 add_trampoline_func(m, NULL, rec);
3896 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3897 ops = ftrace_find_unique_ops(rec);
3899 seq_printf(m, "\tops: %pS (%pS)",
3902 seq_puts(m, "\tops: ERROR!");
3905 if (rec->flags & FTRACE_FL_DIRECT) {
3906 unsigned long direct;
3908 direct = ftrace_find_rec_direct(rec->ip);
3910 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3919 static const struct seq_operations show_ftrace_seq_ops = {
3927 ftrace_avail_open(struct inode *inode, struct file *file)
3929 struct ftrace_iterator *iter;
3932 ret = security_locked_down(LOCKDOWN_TRACEFS);
3936 if (unlikely(ftrace_disabled))
3939 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3943 iter->pg = ftrace_pages_start;
3944 iter->ops = &global_ops;
3950 ftrace_enabled_open(struct inode *inode, struct file *file)
3952 struct ftrace_iterator *iter;
3955 * This shows us what functions are currently being
3956 * traced and by what. Not sure if we want lockdown
3957 * to hide such critical information for an admin.
3958 * Although, perhaps it can show information we don't
3959 * want people to see, but if something is tracing
3960 * something, we probably want to know about it.
3963 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3967 iter->pg = ftrace_pages_start;
3968 iter->flags = FTRACE_ITER_ENABLED;
3969 iter->ops = &global_ops;
3975 ftrace_touched_open(struct inode *inode, struct file *file)
3977 struct ftrace_iterator *iter;
3980 * This shows us what functions have ever been enabled
3981 * (traced, direct, patched, etc). Not sure if we want lockdown
3982 * to hide such critical information for an admin.
3983 * Although, perhaps it can show information we don't
3984 * want people to see, but if something had traced
3985 * something, we probably want to know about it.
3988 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3992 iter->pg = ftrace_pages_start;
3993 iter->flags = FTRACE_ITER_TOUCHED;
3994 iter->ops = &global_ops;
4000 * ftrace_regex_open - initialize function tracer filter files
4001 * @ops: The ftrace_ops that hold the hash filters
4002 * @flag: The type of filter to process
4003 * @inode: The inode, usually passed in to your open routine
4004 * @file: The file, usually passed in to your open routine
4006 * ftrace_regex_open() initializes the filter files for the
4007 * @ops. Depending on @flag it may process the filter hash or
4008 * the notrace hash of @ops. With this called from the open
4009 * routine, you can use ftrace_filter_write() for the write
4010 * routine if @flag has FTRACE_ITER_FILTER set, or
4011 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4012 * tracing_lseek() should be used as the lseek routine, and
4013 * release must call ftrace_regex_release().
4016 ftrace_regex_open(struct ftrace_ops *ops, int flag,
4017 struct inode *inode, struct file *file)
4019 struct ftrace_iterator *iter;
4020 struct ftrace_hash *hash;
4021 struct list_head *mod_head;
4022 struct trace_array *tr = ops->private;
4025 ftrace_ops_init(ops);
4027 if (unlikely(ftrace_disabled))
4030 if (tracing_check_open_get_tr(tr))
4033 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4037 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4044 mutex_lock(&ops->func_hash->regex_lock);
4046 if (flag & FTRACE_ITER_NOTRACE) {
4047 hash = ops->func_hash->notrace_hash;
4048 mod_head = tr ? &tr->mod_notrace : NULL;
4050 hash = ops->func_hash->filter_hash;
4051 mod_head = tr ? &tr->mod_trace : NULL;
4054 iter->mod_list = mod_head;
4056 if (file->f_mode & FMODE_WRITE) {
4057 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4059 if (file->f_flags & O_TRUNC) {
4060 iter->hash = alloc_ftrace_hash(size_bits);
4061 clear_ftrace_mod_list(mod_head);
4063 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4067 trace_parser_put(&iter->parser);
4075 if (file->f_mode & FMODE_READ) {
4076 iter->pg = ftrace_pages_start;
4078 ret = seq_open(file, &show_ftrace_seq_ops);
4080 struct seq_file *m = file->private_data;
4084 free_ftrace_hash(iter->hash);
4085 trace_parser_put(&iter->parser);
4088 file->private_data = iter;
4091 mutex_unlock(&ops->func_hash->regex_lock);
4097 trace_array_put(tr);
4104 ftrace_filter_open(struct inode *inode, struct file *file)
4106 struct ftrace_ops *ops = inode->i_private;
4108 /* Checks for tracefs lockdown */
4109 return ftrace_regex_open(ops,
4110 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4115 ftrace_notrace_open(struct inode *inode, struct file *file)
4117 struct ftrace_ops *ops = inode->i_private;
4119 /* Checks for tracefs lockdown */
4120 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4124 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4125 struct ftrace_glob {
4132 * If symbols in an architecture don't correspond exactly to the user-visible
4133 * name of what they represent, it is possible to define this function to
4134 * perform the necessary adjustments.
4136 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4141 static int ftrace_match(char *str, struct ftrace_glob *g)
4146 str = arch_ftrace_match_adjust(str, g->search);
4150 if (strcmp(str, g->search) == 0)
4153 case MATCH_FRONT_ONLY:
4154 if (strncmp(str, g->search, g->len) == 0)
4157 case MATCH_MIDDLE_ONLY:
4158 if (strstr(str, g->search))
4161 case MATCH_END_ONLY:
4163 if (slen >= g->len &&
4164 memcmp(str + slen - g->len, g->search, g->len) == 0)
4168 if (glob_match(g->search, str))
4177 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4179 struct ftrace_func_entry *entry;
4182 entry = ftrace_lookup_ip(hash, rec->ip);
4184 /* Do nothing if it doesn't exist */
4188 free_hash_entry(hash, entry);
4190 /* Do nothing if it exists */
4194 ret = add_hash_entry(hash, rec->ip);
4200 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4203 long index = simple_strtoul(func_g->search, NULL, 0);
4204 struct ftrace_page *pg;
4205 struct dyn_ftrace *rec;
4207 /* The index starts at 1 */
4211 do_for_each_ftrace_rec(pg, rec) {
4212 if (pg->index <= index) {
4214 /* this is a double loop, break goes to the next page */
4217 rec = &pg->records[index];
4218 enter_record(hash, rec, clear_filter);
4220 } while_for_each_ftrace_rec();
4224 #ifdef FTRACE_MCOUNT_MAX_OFFSET
4225 static int lookup_ip(unsigned long ip, char **modname, char *str)
4227 unsigned long offset;
4229 kallsyms_lookup(ip, NULL, &offset, modname, str);
4230 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4235 static int lookup_ip(unsigned long ip, char **modname, char *str)
4237 kallsyms_lookup(ip, NULL, NULL, modname, str);
4243 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4244 struct ftrace_glob *mod_g, int exclude_mod)
4246 char str[KSYM_SYMBOL_LEN];
4249 if (lookup_ip(rec->ip, &modname, str)) {
4250 /* This should only happen when a rec is disabled */
4251 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4252 !(rec->flags & FTRACE_FL_DISABLED));
4257 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4259 /* blank module name to match all modules */
4261 /* blank module globbing: modname xor exclude_mod */
4262 if (!exclude_mod != !modname)
4268 * exclude_mod is set to trace everything but the given
4269 * module. If it is set and the module matches, then
4270 * return 0. If it is not set, and the module doesn't match
4271 * also return 0. Otherwise, check the function to see if
4274 if (!mod_matches == !exclude_mod)
4277 /* blank search means to match all funcs in the mod */
4282 return ftrace_match(str, func_g);
4286 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4288 struct ftrace_page *pg;
4289 struct dyn_ftrace *rec;
4290 struct ftrace_glob func_g = { .type = MATCH_FULL };
4291 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4292 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4293 int exclude_mod = 0;
4296 int clear_filter = 0;
4299 func_g.type = filter_parse_regex(func, len, &func_g.search,
4301 func_g.len = strlen(func_g.search);
4305 mod_g.type = filter_parse_regex(mod, strlen(mod),
4306 &mod_g.search, &exclude_mod);
4307 mod_g.len = strlen(mod_g.search);
4310 mutex_lock(&ftrace_lock);
4312 if (unlikely(ftrace_disabled))
4315 if (func_g.type == MATCH_INDEX) {
4316 found = add_rec_by_index(hash, &func_g, clear_filter);
4320 do_for_each_ftrace_rec(pg, rec) {
4322 if (rec->flags & FTRACE_FL_DISABLED)
4325 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4326 ret = enter_record(hash, rec, clear_filter);
4334 } while_for_each_ftrace_rec();
4336 mutex_unlock(&ftrace_lock);
4342 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4344 return match_records(hash, buff, len, NULL);
4347 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4348 struct ftrace_ops_hash *old_hash)
4350 struct ftrace_ops *op;
4352 if (!ftrace_enabled)
4355 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4356 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4361 * If this is the shared global_ops filter, then we need to
4362 * check if there is another ops that shares it, is enabled.
4363 * If so, we still need to run the modify code.
4365 if (ops->func_hash != &global_ops.local_hash)
4368 do_for_each_ftrace_op(op, ftrace_ops_list) {
4369 if (op->func_hash == &global_ops.local_hash &&
4370 op->flags & FTRACE_OPS_FL_ENABLED) {
4371 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4372 /* Only need to do this once */
4375 } while_for_each_ftrace_op(op);
4378 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4379 struct ftrace_hash **orig_hash,
4380 struct ftrace_hash *hash,
4383 struct ftrace_ops_hash old_hash_ops;
4384 struct ftrace_hash *old_hash;
4387 old_hash = *orig_hash;
4388 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4389 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4390 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4392 ftrace_ops_update_code(ops, &old_hash_ops);
4393 free_ftrace_hash_rcu(old_hash);
4398 static bool module_exists(const char *module)
4400 /* All modules have the symbol __this_module */
4401 static const char this_mod[] = "__this_module";
4402 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4406 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4408 if (n > sizeof(modname) - 1)
4411 val = module_kallsyms_lookup_name(modname);
4415 static int cache_mod(struct trace_array *tr,
4416 const char *func, char *module, int enable)
4418 struct ftrace_mod_load *ftrace_mod, *n;
4419 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4422 mutex_lock(&ftrace_lock);
4424 /* We do not cache inverse filters */
4425 if (func[0] == '!') {
4429 /* Look to remove this hash */
4430 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4431 if (strcmp(ftrace_mod->module, module) != 0)
4434 /* no func matches all */
4435 if (strcmp(func, "*") == 0 ||
4436 (ftrace_mod->func &&
4437 strcmp(ftrace_mod->func, func) == 0)) {
4439 free_ftrace_mod(ftrace_mod);
4447 /* We only care about modules that have not been loaded yet */
4448 if (module_exists(module))
4451 /* Save this string off, and execute it when the module is loaded */
4452 ret = ftrace_add_mod(tr, func, module, enable);
4454 mutex_unlock(&ftrace_lock);
4460 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4461 int reset, int enable);
4463 #ifdef CONFIG_MODULES
4464 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4465 char *mod, bool enable)
4467 struct ftrace_mod_load *ftrace_mod, *n;
4468 struct ftrace_hash **orig_hash, *new_hash;
4469 LIST_HEAD(process_mods);
4472 mutex_lock(&ops->func_hash->regex_lock);
4475 orig_hash = &ops->func_hash->filter_hash;
4477 orig_hash = &ops->func_hash->notrace_hash;
4479 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4482 goto out; /* warn? */
4484 mutex_lock(&ftrace_lock);
4486 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4488 if (strcmp(ftrace_mod->module, mod) != 0)
4491 if (ftrace_mod->func)
4492 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4494 func = kstrdup("*", GFP_KERNEL);
4496 if (!func) /* warn? */
4499 list_move(&ftrace_mod->list, &process_mods);
4501 /* Use the newly allocated func, as it may be "*" */
4502 kfree(ftrace_mod->func);
4503 ftrace_mod->func = func;
4506 mutex_unlock(&ftrace_lock);
4508 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4510 func = ftrace_mod->func;
4512 /* Grabs ftrace_lock, which is why we have this extra step */
4513 match_records(new_hash, func, strlen(func), mod);
4514 free_ftrace_mod(ftrace_mod);
4517 if (enable && list_empty(head))
4518 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4520 mutex_lock(&ftrace_lock);
4522 ftrace_hash_move_and_update_ops(ops, orig_hash,
4524 mutex_unlock(&ftrace_lock);
4527 mutex_unlock(&ops->func_hash->regex_lock);
4529 free_ftrace_hash(new_hash);
4532 static void process_cached_mods(const char *mod_name)
4534 struct trace_array *tr;
4537 mod = kstrdup(mod_name, GFP_KERNEL);
4541 mutex_lock(&trace_types_lock);
4542 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4543 if (!list_empty(&tr->mod_trace))
4544 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4545 if (!list_empty(&tr->mod_notrace))
4546 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4548 mutex_unlock(&trace_types_lock);
4555 * We register the module command as a template to show others how
4556 * to register the a command as well.
4560 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4561 char *func_orig, char *cmd, char *module, int enable)
4566 /* match_records() modifies func, and we need the original */
4567 func = kstrdup(func_orig, GFP_KERNEL);
4572 * cmd == 'mod' because we only registered this func
4573 * for the 'mod' ftrace_func_command.
4574 * But if you register one func with multiple commands,
4575 * you can tell which command was used by the cmd
4578 ret = match_records(hash, func, strlen(func), module);
4582 return cache_mod(tr, func_orig, module, enable);
4588 static struct ftrace_func_command ftrace_mod_cmd = {
4590 .func = ftrace_mod_callback,
4593 static int __init ftrace_mod_cmd_init(void)
4595 return register_ftrace_command(&ftrace_mod_cmd);
4597 core_initcall(ftrace_mod_cmd_init);
4599 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4600 struct ftrace_ops *op, struct ftrace_regs *fregs)
4602 struct ftrace_probe_ops *probe_ops;
4603 struct ftrace_func_probe *probe;
4605 probe = container_of(op, struct ftrace_func_probe, ops);
4606 probe_ops = probe->probe_ops;
4609 * Disable preemption for these calls to prevent a RCU grace
4610 * period. This syncs the hash iteration and freeing of items
4611 * on the hash. rcu_read_lock is too dangerous here.
4613 preempt_disable_notrace();
4614 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4615 preempt_enable_notrace();
4618 struct ftrace_func_map {
4619 struct ftrace_func_entry entry;
4623 struct ftrace_func_mapper {
4624 struct ftrace_hash hash;
4628 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4630 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4632 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4634 struct ftrace_hash *hash;
4637 * The mapper is simply a ftrace_hash, but since the entries
4638 * in the hash are not ftrace_func_entry type, we define it
4639 * as a separate structure.
4641 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4642 return (struct ftrace_func_mapper *)hash;
4646 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4647 * @mapper: The mapper that has the ip maps
4648 * @ip: the instruction pointer to find the data for
4650 * Returns the data mapped to @ip if found otherwise NULL. The return
4651 * is actually the address of the mapper data pointer. The address is
4652 * returned for use cases where the data is no bigger than a long, and
4653 * the user can use the data pointer as its data instead of having to
4654 * allocate more memory for the reference.
4656 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4659 struct ftrace_func_entry *entry;
4660 struct ftrace_func_map *map;
4662 entry = ftrace_lookup_ip(&mapper->hash, ip);
4666 map = (struct ftrace_func_map *)entry;
4671 * ftrace_func_mapper_add_ip - Map some data to an ip
4672 * @mapper: The mapper that has the ip maps
4673 * @ip: The instruction pointer address to map @data to
4674 * @data: The data to map to @ip
4676 * Returns 0 on success otherwise an error.
4678 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4679 unsigned long ip, void *data)
4681 struct ftrace_func_entry *entry;
4682 struct ftrace_func_map *map;
4684 entry = ftrace_lookup_ip(&mapper->hash, ip);
4688 map = kmalloc(sizeof(*map), GFP_KERNEL);
4695 __add_hash_entry(&mapper->hash, &map->entry);
4701 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4702 * @mapper: The mapper that has the ip maps
4703 * @ip: The instruction pointer address to remove the data from
4705 * Returns the data if it is found, otherwise NULL.
4706 * Note, if the data pointer is used as the data itself, (see
4707 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4708 * if the data pointer was set to zero.
4710 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4713 struct ftrace_func_entry *entry;
4714 struct ftrace_func_map *map;
4717 entry = ftrace_lookup_ip(&mapper->hash, ip);
4721 map = (struct ftrace_func_map *)entry;
4724 remove_hash_entry(&mapper->hash, entry);
4731 * free_ftrace_func_mapper - free a mapping of ips and data
4732 * @mapper: The mapper that has the ip maps
4733 * @free_func: A function to be called on each data item.
4735 * This is used to free the function mapper. The @free_func is optional
4736 * and can be used if the data needs to be freed as well.
4738 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4739 ftrace_mapper_func free_func)
4741 struct ftrace_func_entry *entry;
4742 struct ftrace_func_map *map;
4743 struct hlist_head *hhd;
4749 if (free_func && mapper->hash.count) {
4750 size = 1 << mapper->hash.size_bits;
4751 for (i = 0; i < size; i++) {
4752 hhd = &mapper->hash.buckets[i];
4753 hlist_for_each_entry(entry, hhd, hlist) {
4754 map = (struct ftrace_func_map *)entry;
4759 free_ftrace_hash(&mapper->hash);
4762 static void release_probe(struct ftrace_func_probe *probe)
4764 struct ftrace_probe_ops *probe_ops;
4766 mutex_lock(&ftrace_lock);
4768 WARN_ON(probe->ref <= 0);
4770 /* Subtract the ref that was used to protect this instance */
4774 probe_ops = probe->probe_ops;
4776 * Sending zero as ip tells probe_ops to free
4777 * the probe->data itself
4779 if (probe_ops->free)
4780 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4781 list_del(&probe->list);
4784 mutex_unlock(&ftrace_lock);
4787 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4790 * Add one ref to keep it from being freed when releasing the
4791 * ftrace_lock mutex.
4797 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4798 struct ftrace_probe_ops *probe_ops,
4801 struct ftrace_func_probe *probe = NULL, *iter;
4802 struct ftrace_func_entry *entry;
4803 struct ftrace_hash **orig_hash;
4804 struct ftrace_hash *old_hash;
4805 struct ftrace_hash *hash;
4814 /* We do not support '!' for function probes */
4815 if (WARN_ON(glob[0] == '!'))
4819 mutex_lock(&ftrace_lock);
4820 /* Check if the probe_ops is already registered */
4821 list_for_each_entry(iter, &tr->func_probes, list) {
4822 if (iter->probe_ops == probe_ops) {
4828 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4830 mutex_unlock(&ftrace_lock);
4833 probe->probe_ops = probe_ops;
4834 probe->ops.func = function_trace_probe_call;
4836 ftrace_ops_init(&probe->ops);
4837 list_add(&probe->list, &tr->func_probes);
4840 acquire_probe_locked(probe);
4842 mutex_unlock(&ftrace_lock);
4845 * Note, there's a small window here that the func_hash->filter_hash
4846 * may be NULL or empty. Need to be careful when reading the loop.
4848 mutex_lock(&probe->ops.func_hash->regex_lock);
4850 orig_hash = &probe->ops.func_hash->filter_hash;
4851 old_hash = *orig_hash;
4852 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4859 ret = ftrace_match_records(hash, glob, strlen(glob));
4861 /* Nothing found? */
4868 size = 1 << hash->size_bits;
4869 for (i = 0; i < size; i++) {
4870 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4871 if (ftrace_lookup_ip(old_hash, entry->ip))
4874 * The caller might want to do something special
4875 * for each function we find. We call the callback
4876 * to give the caller an opportunity to do so.
4878 if (probe_ops->init) {
4879 ret = probe_ops->init(probe_ops, tr,
4883 if (probe_ops->free && count)
4884 probe_ops->free(probe_ops, tr,
4894 mutex_lock(&ftrace_lock);
4897 /* Nothing was added? */
4902 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4907 /* One ref for each new function traced */
4908 probe->ref += count;
4910 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4911 ret = ftrace_startup(&probe->ops, 0);
4914 mutex_unlock(&ftrace_lock);
4919 mutex_unlock(&probe->ops.func_hash->regex_lock);
4920 free_ftrace_hash(hash);
4922 release_probe(probe);
4927 if (!probe_ops->free || !count)
4930 /* Failed to do the move, need to call the free functions */
4931 for (i = 0; i < size; i++) {
4932 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4933 if (ftrace_lookup_ip(old_hash, entry->ip))
4935 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4942 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4943 struct ftrace_probe_ops *probe_ops)
4945 struct ftrace_func_probe *probe = NULL, *iter;
4946 struct ftrace_ops_hash old_hash_ops;
4947 struct ftrace_func_entry *entry;
4948 struct ftrace_glob func_g;
4949 struct ftrace_hash **orig_hash;
4950 struct ftrace_hash *old_hash;
4951 struct ftrace_hash *hash = NULL;
4952 struct hlist_node *tmp;
4953 struct hlist_head hhd;
4954 char str[KSYM_SYMBOL_LEN];
4956 int i, ret = -ENODEV;
4959 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4960 func_g.search = NULL;
4964 func_g.type = filter_parse_regex(glob, strlen(glob),
4965 &func_g.search, ¬);
4966 func_g.len = strlen(func_g.search);
4968 /* we do not support '!' for function probes */
4973 mutex_lock(&ftrace_lock);
4974 /* Check if the probe_ops is already registered */
4975 list_for_each_entry(iter, &tr->func_probes, list) {
4976 if (iter->probe_ops == probe_ops) {
4982 goto err_unlock_ftrace;
4985 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4986 goto err_unlock_ftrace;
4988 acquire_probe_locked(probe);
4990 mutex_unlock(&ftrace_lock);
4992 mutex_lock(&probe->ops.func_hash->regex_lock);
4994 orig_hash = &probe->ops.func_hash->filter_hash;
4995 old_hash = *orig_hash;
4997 if (ftrace_hash_empty(old_hash))
5000 old_hash_ops.filter_hash = old_hash;
5001 /* Probes only have filters */
5002 old_hash_ops.notrace_hash = NULL;
5005 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5009 INIT_HLIST_HEAD(&hhd);
5011 size = 1 << hash->size_bits;
5012 for (i = 0; i < size; i++) {
5013 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5015 if (func_g.search) {
5016 kallsyms_lookup(entry->ip, NULL, NULL,
5018 if (!ftrace_match(str, &func_g))
5022 remove_hash_entry(hash, entry);
5023 hlist_add_head(&entry->hlist, &hhd);
5027 /* Nothing found? */
5033 mutex_lock(&ftrace_lock);
5035 WARN_ON(probe->ref < count);
5037 probe->ref -= count;
5039 if (ftrace_hash_empty(hash))
5040 ftrace_shutdown(&probe->ops, 0);
5042 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5045 /* still need to update the function call sites */
5046 if (ftrace_enabled && !ftrace_hash_empty(hash))
5047 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5051 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5052 hlist_del(&entry->hlist);
5053 if (probe_ops->free)
5054 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5057 mutex_unlock(&ftrace_lock);
5060 mutex_unlock(&probe->ops.func_hash->regex_lock);
5061 free_ftrace_hash(hash);
5063 release_probe(probe);
5068 mutex_unlock(&ftrace_lock);
5072 void clear_ftrace_function_probes(struct trace_array *tr)
5074 struct ftrace_func_probe *probe, *n;
5076 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5077 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5080 static LIST_HEAD(ftrace_commands);
5081 static DEFINE_MUTEX(ftrace_cmd_mutex);
5084 * Currently we only register ftrace commands from __init, so mark this
5087 __init int register_ftrace_command(struct ftrace_func_command *cmd)
5089 struct ftrace_func_command *p;
5092 mutex_lock(&ftrace_cmd_mutex);
5093 list_for_each_entry(p, &ftrace_commands, list) {
5094 if (strcmp(cmd->name, p->name) == 0) {
5099 list_add(&cmd->list, &ftrace_commands);
5101 mutex_unlock(&ftrace_cmd_mutex);
5107 * Currently we only unregister ftrace commands from __init, so mark
5110 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5112 struct ftrace_func_command *p, *n;
5115 mutex_lock(&ftrace_cmd_mutex);
5116 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5117 if (strcmp(cmd->name, p->name) == 0) {
5119 list_del_init(&p->list);
5124 mutex_unlock(&ftrace_cmd_mutex);
5129 static int ftrace_process_regex(struct ftrace_iterator *iter,
5130 char *buff, int len, int enable)
5132 struct ftrace_hash *hash = iter->hash;
5133 struct trace_array *tr = iter->ops->private;
5134 char *func, *command, *next = buff;
5135 struct ftrace_func_command *p;
5138 func = strsep(&next, ":");
5141 ret = ftrace_match_records(hash, func, len);
5151 command = strsep(&next, ":");
5153 mutex_lock(&ftrace_cmd_mutex);
5154 list_for_each_entry(p, &ftrace_commands, list) {
5155 if (strcmp(p->name, command) == 0) {
5156 ret = p->func(tr, hash, func, command, next, enable);
5161 mutex_unlock(&ftrace_cmd_mutex);
5167 ftrace_regex_write(struct file *file, const char __user *ubuf,
5168 size_t cnt, loff_t *ppos, int enable)
5170 struct ftrace_iterator *iter;
5171 struct trace_parser *parser;
5177 if (file->f_mode & FMODE_READ) {
5178 struct seq_file *m = file->private_data;
5181 iter = file->private_data;
5183 if (unlikely(ftrace_disabled))
5186 /* iter->hash is a local copy, so we don't need regex_lock */
5188 parser = &iter->parser;
5189 read = trace_get_user(parser, ubuf, cnt, ppos);
5191 if (read >= 0 && trace_parser_loaded(parser) &&
5192 !trace_parser_cont(parser)) {
5193 ret = ftrace_process_regex(iter, parser->buffer,
5194 parser->idx, enable);
5195 trace_parser_clear(parser);
5206 ftrace_filter_write(struct file *file, const char __user *ubuf,
5207 size_t cnt, loff_t *ppos)
5209 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5213 ftrace_notrace_write(struct file *file, const char __user *ubuf,
5214 size_t cnt, loff_t *ppos)
5216 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5220 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5222 struct ftrace_func_entry *entry;
5224 ip = ftrace_location(ip);
5229 entry = ftrace_lookup_ip(hash, ip);
5232 free_hash_entry(hash, entry);
5236 return add_hash_entry(hash, ip);
5240 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5241 unsigned int cnt, int remove)
5246 for (i = 0; i < cnt; i++) {
5247 err = __ftrace_match_addr(hash, ips[i], remove);
5250 * This expects the @hash is a temporary hash and if this
5251 * fails the caller must free the @hash.
5260 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5261 unsigned long *ips, unsigned int cnt,
5262 int remove, int reset, int enable)
5264 struct ftrace_hash **orig_hash;
5265 struct ftrace_hash *hash;
5268 if (unlikely(ftrace_disabled))
5271 mutex_lock(&ops->func_hash->regex_lock);
5274 orig_hash = &ops->func_hash->filter_hash;
5276 orig_hash = &ops->func_hash->notrace_hash;
5279 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5281 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5285 goto out_regex_unlock;
5288 if (buf && !ftrace_match_records(hash, buf, len)) {
5290 goto out_regex_unlock;
5293 ret = ftrace_match_addr(hash, ips, cnt, remove);
5295 goto out_regex_unlock;
5298 mutex_lock(&ftrace_lock);
5299 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5300 mutex_unlock(&ftrace_lock);
5303 mutex_unlock(&ops->func_hash->regex_lock);
5305 free_ftrace_hash(hash);
5310 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5311 int remove, int reset, int enable)
5313 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5316 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5318 struct ftrace_direct_func {
5319 struct list_head next;
5324 static LIST_HEAD(ftrace_direct_funcs);
5326 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5328 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5330 static int check_direct_multi(struct ftrace_ops *ops)
5332 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5334 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5339 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5341 struct ftrace_func_entry *entry, *del;
5344 size = 1 << hash->size_bits;
5345 for (i = 0; i < size; i++) {
5346 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5347 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5348 if (del && del->direct == addr) {
5349 remove_hash_entry(direct_functions, del);
5357 * register_ftrace_direct - Call a custom trampoline directly
5358 * for multiple functions registered in @ops
5359 * @ops: The address of the struct ftrace_ops object
5360 * @addr: The address of the trampoline to call at @ops functions
5362 * This is used to connect a direct calls to @addr from the nop locations
5363 * of the functions registered in @ops (with by ftrace_set_filter_ip
5366 * The location that it calls (@addr) must be able to handle a direct call,
5367 * and save the parameters of the function being traced, and restore them
5368 * (or inject new ones if needed), before returning.
5372 * -EINVAL - The @ops object was already registered with this call or
5373 * when there are no functions in @ops object.
5374 * -EBUSY - Another direct function is already attached (there can be only one)
5375 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5376 * -ENOMEM - There was an allocation failure.
5378 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5380 struct ftrace_hash *hash, *free_hash = NULL;
5381 struct ftrace_func_entry *entry, *new;
5382 int err = -EBUSY, size, i;
5384 if (ops->func || ops->trampoline)
5386 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5388 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5391 hash = ops->func_hash->filter_hash;
5392 if (ftrace_hash_empty(hash))
5395 mutex_lock(&direct_mutex);
5397 /* Make sure requested entries are not already registered.. */
5398 size = 1 << hash->size_bits;
5399 for (i = 0; i < size; i++) {
5400 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5401 if (ftrace_find_rec_direct(entry->ip))
5406 /* ... and insert them to direct_functions hash. */
5408 for (i = 0; i < size; i++) {
5409 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5410 new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5413 entry->direct = addr;
5417 ops->func = call_direct_funcs;
5418 ops->flags = MULTI_FLAGS;
5419 ops->trampoline = FTRACE_REGS_ADDR;
5420 ops->direct_call = addr;
5422 err = register_ftrace_function_nolock(ops);
5426 remove_direct_functions_hash(hash, addr);
5429 mutex_unlock(&direct_mutex);
5432 synchronize_rcu_tasks();
5433 free_ftrace_hash(free_hash);
5437 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5440 * unregister_ftrace_direct - Remove calls to custom trampoline
5441 * previously registered by register_ftrace_direct for @ops object.
5442 * @ops: The address of the struct ftrace_ops object
5444 * This is used to remove a direct calls to @addr from the nop locations
5445 * of the functions registered in @ops (with by ftrace_set_filter_ip
5450 * -EINVAL - The @ops object was not properly registered.
5452 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5455 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5458 if (check_direct_multi(ops))
5460 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5463 mutex_lock(&direct_mutex);
5464 err = unregister_ftrace_function(ops);
5465 remove_direct_functions_hash(hash, addr);
5466 mutex_unlock(&direct_mutex);
5468 /* cleanup for possible another register call */
5470 ops->trampoline = 0;
5473 ftrace_free_filter(ops);
5476 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5479 __modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5481 struct ftrace_hash *hash;
5482 struct ftrace_func_entry *entry, *iter;
5483 static struct ftrace_ops tmp_ops = {
5484 .func = ftrace_stub,
5485 .flags = FTRACE_OPS_FL_STUB,
5490 lockdep_assert_held_once(&direct_mutex);
5492 /* Enable the tmp_ops to have the same functions as the direct ops */
5493 ftrace_ops_init(&tmp_ops);
5494 tmp_ops.func_hash = ops->func_hash;
5495 tmp_ops.direct_call = addr;
5497 err = register_ftrace_function_nolock(&tmp_ops);
5502 * Now the ftrace_ops_list_func() is called to do the direct callers.
5503 * We can safely change the direct functions attached to each entry.
5505 mutex_lock(&ftrace_lock);
5507 hash = ops->func_hash->filter_hash;
5508 size = 1 << hash->size_bits;
5509 for (i = 0; i < size; i++) {
5510 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5511 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5514 entry->direct = addr;
5517 /* Prevent store tearing if a trampoline concurrently accesses the value */
5518 WRITE_ONCE(ops->direct_call, addr);
5520 mutex_unlock(&ftrace_lock);
5522 /* Removing the tmp_ops will add the updated direct callers to the functions */
5523 unregister_ftrace_function(&tmp_ops);
5529 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5530 * to call something else
5531 * @ops: The address of the struct ftrace_ops object
5532 * @addr: The address of the new trampoline to call at @ops functions
5534 * This is used to unregister currently registered direct caller and
5535 * register new one @addr on functions registered in @ops object.
5537 * Note there's window between ftrace_shutdown and ftrace_startup calls
5538 * where there will be no callbacks called.
5540 * Caller should already have direct_mutex locked, so we don't lock
5541 * direct_mutex here.
5543 * Returns: zero on success. Non zero on error, which includes:
5544 * -EINVAL - The @ops object was not properly registered.
5546 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5548 if (check_direct_multi(ops))
5550 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5553 return __modify_ftrace_direct(ops, addr);
5555 EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5558 * modify_ftrace_direct - Modify an existing direct 'multi' call
5559 * to call something else
5560 * @ops: The address of the struct ftrace_ops object
5561 * @addr: The address of the new trampoline to call at @ops functions
5563 * This is used to unregister currently registered direct caller and
5564 * register new one @addr on functions registered in @ops object.
5566 * Note there's window between ftrace_shutdown and ftrace_startup calls
5567 * where there will be no callbacks called.
5569 * Returns: zero on success. Non zero on error, which includes:
5570 * -EINVAL - The @ops object was not properly registered.
5572 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5576 if (check_direct_multi(ops))
5578 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5581 mutex_lock(&direct_mutex);
5582 err = __modify_ftrace_direct(ops, addr);
5583 mutex_unlock(&direct_mutex);
5586 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5587 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5590 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5591 * @ops - the ops to set the filter with
5592 * @ip - the address to add to or remove from the filter.
5593 * @remove - non zero to remove the ip from the filter
5594 * @reset - non zero to reset all filters before applying this filter.
5596 * Filters denote which functions should be enabled when tracing is enabled
5597 * If @ip is NULL, it fails to update filter.
5599 * This can allocate memory which must be freed before @ops can be freed,
5600 * either by removing each filtered addr or by using
5601 * ftrace_free_filter(@ops).
5603 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5604 int remove, int reset)
5606 ftrace_ops_init(ops);
5607 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5609 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5612 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5613 * @ops - the ops to set the filter with
5614 * @ips - the array of addresses to add to or remove from the filter.
5615 * @cnt - the number of addresses in @ips
5616 * @remove - non zero to remove ips from the filter
5617 * @reset - non zero to reset all filters before applying this filter.
5619 * Filters denote which functions should be enabled when tracing is enabled
5620 * If @ips array or any ip specified within is NULL , it fails to update filter.
5622 * This can allocate memory which must be freed before @ops can be freed,
5623 * either by removing each filtered addr or by using
5624 * ftrace_free_filter(@ops).
5626 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5627 unsigned int cnt, int remove, int reset)
5629 ftrace_ops_init(ops);
5630 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5632 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5635 * ftrace_ops_set_global_filter - setup ops to use global filters
5636 * @ops - the ops which will use the global filters
5638 * ftrace users who need global function trace filtering should call this.
5639 * It can set the global filter only if ops were not initialized before.
5641 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5643 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5646 ftrace_ops_init(ops);
5647 ops->func_hash = &global_ops.local_hash;
5649 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5652 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5653 int reset, int enable)
5655 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5659 * ftrace_set_filter - set a function to filter on in ftrace
5660 * @ops - the ops to set the filter with
5661 * @buf - the string that holds the function filter text.
5662 * @len - the length of the string.
5663 * @reset - non zero to reset all filters before applying this filter.
5665 * Filters denote which functions should be enabled when tracing is enabled.
5666 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5668 * This can allocate memory which must be freed before @ops can be freed,
5669 * either by removing each filtered addr or by using
5670 * ftrace_free_filter(@ops).
5672 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5675 ftrace_ops_init(ops);
5676 return ftrace_set_regex(ops, buf, len, reset, 1);
5678 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5681 * ftrace_set_notrace - set a function to not trace in ftrace
5682 * @ops - the ops to set the notrace filter with
5683 * @buf - the string that holds the function notrace text.
5684 * @len - the length of the string.
5685 * @reset - non zero to reset all filters before applying this filter.
5687 * Notrace Filters denote which functions should not be enabled when tracing
5688 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5691 * This can allocate memory which must be freed before @ops can be freed,
5692 * either by removing each filtered addr or by using
5693 * ftrace_free_filter(@ops).
5695 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5698 ftrace_ops_init(ops);
5699 return ftrace_set_regex(ops, buf, len, reset, 0);
5701 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5703 * ftrace_set_global_filter - set a function to filter on with global tracers
5704 * @buf - the string that holds the function filter text.
5705 * @len - the length of the string.
5706 * @reset - non zero to reset all filters before applying this filter.
5708 * Filters denote which functions should be enabled when tracing is enabled.
5709 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5711 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5713 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5715 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5718 * ftrace_set_global_notrace - set a function to not trace with global tracers
5719 * @buf - the string that holds the function notrace text.
5720 * @len - the length of the string.
5721 * @reset - non zero to reset all filters before applying this filter.
5723 * Notrace Filters denote which functions should not be enabled when tracing
5724 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5727 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5729 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5731 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5734 * command line interface to allow users to set filters on boot up.
5736 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5737 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5738 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5740 /* Used by function selftest to not test if filter is set */
5741 bool ftrace_filter_param __initdata;
5743 static int __init set_ftrace_notrace(char *str)
5745 ftrace_filter_param = true;
5746 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5749 __setup("ftrace_notrace=", set_ftrace_notrace);
5751 static int __init set_ftrace_filter(char *str)
5753 ftrace_filter_param = true;
5754 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5757 __setup("ftrace_filter=", set_ftrace_filter);
5759 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5760 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5761 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5762 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5764 static int __init set_graph_function(char *str)
5766 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5769 __setup("ftrace_graph_filter=", set_graph_function);
5771 static int __init set_graph_notrace_function(char *str)
5773 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5776 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5778 static int __init set_graph_max_depth_function(char *str)
5782 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5785 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5787 static void __init set_ftrace_early_graph(char *buf, int enable)
5791 struct ftrace_hash *hash;
5793 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5794 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5798 func = strsep(&buf, ",");
5799 /* we allow only one expression at a time */
5800 ret = ftrace_graph_set_hash(hash, func);
5802 printk(KERN_DEBUG "ftrace: function %s not "
5803 "traceable\n", func);
5807 ftrace_graph_hash = hash;
5809 ftrace_graph_notrace_hash = hash;
5811 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5814 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5818 ftrace_ops_init(ops);
5821 func = strsep(&buf, ",");
5822 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5826 static void __init set_ftrace_early_filters(void)
5828 if (ftrace_filter_buf[0])
5829 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5830 if (ftrace_notrace_buf[0])
5831 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5832 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5833 if (ftrace_graph_buf[0])
5834 set_ftrace_early_graph(ftrace_graph_buf, 1);
5835 if (ftrace_graph_notrace_buf[0])
5836 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5837 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5840 int ftrace_regex_release(struct inode *inode, struct file *file)
5842 struct seq_file *m = (struct seq_file *)file->private_data;
5843 struct ftrace_iterator *iter;
5844 struct ftrace_hash **orig_hash;
5845 struct trace_parser *parser;
5848 if (file->f_mode & FMODE_READ) {
5850 seq_release(inode, file);
5852 iter = file->private_data;
5854 parser = &iter->parser;
5855 if (trace_parser_loaded(parser)) {
5856 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5858 ftrace_process_regex(iter, parser->buffer,
5859 parser->idx, enable);
5862 trace_parser_put(parser);
5864 mutex_lock(&iter->ops->func_hash->regex_lock);
5866 if (file->f_mode & FMODE_WRITE) {
5867 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5870 orig_hash = &iter->ops->func_hash->filter_hash;
5872 if (list_empty(&iter->tr->mod_trace))
5873 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5875 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5878 orig_hash = &iter->ops->func_hash->notrace_hash;
5880 mutex_lock(&ftrace_lock);
5881 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5882 iter->hash, filter_hash);
5883 mutex_unlock(&ftrace_lock);
5885 /* For read only, the hash is the ops hash */
5889 mutex_unlock(&iter->ops->func_hash->regex_lock);
5890 free_ftrace_hash(iter->hash);
5892 trace_array_put(iter->tr);
5898 static const struct file_operations ftrace_avail_fops = {
5899 .open = ftrace_avail_open,
5901 .llseek = seq_lseek,
5902 .release = seq_release_private,
5905 static const struct file_operations ftrace_enabled_fops = {
5906 .open = ftrace_enabled_open,
5908 .llseek = seq_lseek,
5909 .release = seq_release_private,
5912 static const struct file_operations ftrace_touched_fops = {
5913 .open = ftrace_touched_open,
5915 .llseek = seq_lseek,
5916 .release = seq_release_private,
5919 static const struct file_operations ftrace_filter_fops = {
5920 .open = ftrace_filter_open,
5922 .write = ftrace_filter_write,
5923 .llseek = tracing_lseek,
5924 .release = ftrace_regex_release,
5927 static const struct file_operations ftrace_notrace_fops = {
5928 .open = ftrace_notrace_open,
5930 .write = ftrace_notrace_write,
5931 .llseek = tracing_lseek,
5932 .release = ftrace_regex_release,
5935 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5937 static DEFINE_MUTEX(graph_lock);
5939 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5940 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5942 enum graph_filter_type {
5943 GRAPH_FILTER_NOTRACE = 0,
5944 GRAPH_FILTER_FUNCTION,
5947 #define FTRACE_GRAPH_EMPTY ((void *)1)
5949 struct ftrace_graph_data {
5950 struct ftrace_hash *hash;
5951 struct ftrace_func_entry *entry;
5952 int idx; /* for hash table iteration */
5953 enum graph_filter_type type;
5954 struct ftrace_hash *new_hash;
5955 const struct seq_operations *seq_ops;
5956 struct trace_parser parser;
5960 __g_next(struct seq_file *m, loff_t *pos)
5962 struct ftrace_graph_data *fgd = m->private;
5963 struct ftrace_func_entry *entry = fgd->entry;
5964 struct hlist_head *head;
5965 int i, idx = fgd->idx;
5967 if (*pos >= fgd->hash->count)
5971 hlist_for_each_entry_continue(entry, hlist) {
5979 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5980 head = &fgd->hash->buckets[i];
5981 hlist_for_each_entry(entry, head, hlist) {
5991 g_next(struct seq_file *m, void *v, loff_t *pos)
5994 return __g_next(m, pos);
5997 static void *g_start(struct seq_file *m, loff_t *pos)
5999 struct ftrace_graph_data *fgd = m->private;
6001 mutex_lock(&graph_lock);
6003 if (fgd->type == GRAPH_FILTER_FUNCTION)
6004 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6005 lockdep_is_held(&graph_lock));
6007 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6008 lockdep_is_held(&graph_lock));
6010 /* Nothing, tell g_show to print all functions are enabled */
6011 if (ftrace_hash_empty(fgd->hash) && !*pos)
6012 return FTRACE_GRAPH_EMPTY;
6016 return __g_next(m, pos);
6019 static void g_stop(struct seq_file *m, void *p)
6021 mutex_unlock(&graph_lock);
6024 static int g_show(struct seq_file *m, void *v)
6026 struct ftrace_func_entry *entry = v;
6031 if (entry == FTRACE_GRAPH_EMPTY) {
6032 struct ftrace_graph_data *fgd = m->private;
6034 if (fgd->type == GRAPH_FILTER_FUNCTION)
6035 seq_puts(m, "#### all functions enabled ####\n");
6037 seq_puts(m, "#### no functions disabled ####\n");
6041 seq_printf(m, "%ps\n", (void *)entry->ip);
6046 static const struct seq_operations ftrace_graph_seq_ops = {
6054 __ftrace_graph_open(struct inode *inode, struct file *file,
6055 struct ftrace_graph_data *fgd)
6058 struct ftrace_hash *new_hash = NULL;
6060 ret = security_locked_down(LOCKDOWN_TRACEFS);
6064 if (file->f_mode & FMODE_WRITE) {
6065 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6067 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6070 if (file->f_flags & O_TRUNC)
6071 new_hash = alloc_ftrace_hash(size_bits);
6073 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6081 if (file->f_mode & FMODE_READ) {
6082 ret = seq_open(file, &ftrace_graph_seq_ops);
6084 struct seq_file *m = file->private_data;
6088 free_ftrace_hash(new_hash);
6092 file->private_data = fgd;
6095 if (ret < 0 && file->f_mode & FMODE_WRITE)
6096 trace_parser_put(&fgd->parser);
6098 fgd->new_hash = new_hash;
6101 * All uses of fgd->hash must be taken with the graph_lock
6102 * held. The graph_lock is going to be released, so force
6103 * fgd->hash to be reinitialized when it is taken again.
6111 ftrace_graph_open(struct inode *inode, struct file *file)
6113 struct ftrace_graph_data *fgd;
6116 if (unlikely(ftrace_disabled))
6119 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6123 mutex_lock(&graph_lock);
6125 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6126 lockdep_is_held(&graph_lock));
6127 fgd->type = GRAPH_FILTER_FUNCTION;
6128 fgd->seq_ops = &ftrace_graph_seq_ops;
6130 ret = __ftrace_graph_open(inode, file, fgd);
6134 mutex_unlock(&graph_lock);
6139 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6141 struct ftrace_graph_data *fgd;
6144 if (unlikely(ftrace_disabled))
6147 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6151 mutex_lock(&graph_lock);
6153 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6154 lockdep_is_held(&graph_lock));
6155 fgd->type = GRAPH_FILTER_NOTRACE;
6156 fgd->seq_ops = &ftrace_graph_seq_ops;
6158 ret = __ftrace_graph_open(inode, file, fgd);
6162 mutex_unlock(&graph_lock);
6167 ftrace_graph_release(struct inode *inode, struct file *file)
6169 struct ftrace_graph_data *fgd;
6170 struct ftrace_hash *old_hash, *new_hash;
6171 struct trace_parser *parser;
6174 if (file->f_mode & FMODE_READ) {
6175 struct seq_file *m = file->private_data;
6178 seq_release(inode, file);
6180 fgd = file->private_data;
6184 if (file->f_mode & FMODE_WRITE) {
6186 parser = &fgd->parser;
6188 if (trace_parser_loaded((parser))) {
6189 ret = ftrace_graph_set_hash(fgd->new_hash,
6193 trace_parser_put(parser);
6195 new_hash = __ftrace_hash_move(fgd->new_hash);
6201 mutex_lock(&graph_lock);
6203 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6204 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6205 lockdep_is_held(&graph_lock));
6206 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6208 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6209 lockdep_is_held(&graph_lock));
6210 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6213 mutex_unlock(&graph_lock);
6216 * We need to do a hard force of sched synchronization.
6217 * This is because we use preempt_disable() to do RCU, but
6218 * the function tracers can be called where RCU is not watching
6219 * (like before user_exit()). We can not rely on the RCU
6220 * infrastructure to do the synchronization, thus we must do it
6223 if (old_hash != EMPTY_HASH)
6224 synchronize_rcu_tasks_rude();
6226 free_ftrace_hash(old_hash);
6230 free_ftrace_hash(fgd->new_hash);
6237 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6239 struct ftrace_glob func_g;
6240 struct dyn_ftrace *rec;
6241 struct ftrace_page *pg;
6242 struct ftrace_func_entry *entry;
6247 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6248 &func_g.search, ¬);
6250 func_g.len = strlen(func_g.search);
6252 mutex_lock(&ftrace_lock);
6254 if (unlikely(ftrace_disabled)) {
6255 mutex_unlock(&ftrace_lock);
6259 do_for_each_ftrace_rec(pg, rec) {
6261 if (rec->flags & FTRACE_FL_DISABLED)
6264 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6265 entry = ftrace_lookup_ip(hash, rec->ip);
6272 if (add_hash_entry(hash, rec->ip) < 0)
6276 free_hash_entry(hash, entry);
6281 } while_for_each_ftrace_rec();
6283 mutex_unlock(&ftrace_lock);
6292 ftrace_graph_write(struct file *file, const char __user *ubuf,
6293 size_t cnt, loff_t *ppos)
6295 ssize_t read, ret = 0;
6296 struct ftrace_graph_data *fgd = file->private_data;
6297 struct trace_parser *parser;
6302 /* Read mode uses seq functions */
6303 if (file->f_mode & FMODE_READ) {
6304 struct seq_file *m = file->private_data;
6308 parser = &fgd->parser;
6310 read = trace_get_user(parser, ubuf, cnt, ppos);
6312 if (read >= 0 && trace_parser_loaded(parser) &&
6313 !trace_parser_cont(parser)) {
6315 ret = ftrace_graph_set_hash(fgd->new_hash,
6317 trace_parser_clear(parser);
6326 static const struct file_operations ftrace_graph_fops = {
6327 .open = ftrace_graph_open,
6329 .write = ftrace_graph_write,
6330 .llseek = tracing_lseek,
6331 .release = ftrace_graph_release,
6334 static const struct file_operations ftrace_graph_notrace_fops = {
6335 .open = ftrace_graph_notrace_open,
6337 .write = ftrace_graph_write,
6338 .llseek = tracing_lseek,
6339 .release = ftrace_graph_release,
6341 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6343 void ftrace_create_filter_files(struct ftrace_ops *ops,
6344 struct dentry *parent)
6347 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6348 ops, &ftrace_filter_fops);
6350 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6351 ops, &ftrace_notrace_fops);
6355 * The name "destroy_filter_files" is really a misnomer. Although
6356 * in the future, it may actually delete the files, but this is
6357 * really intended to make sure the ops passed in are disabled
6358 * and that when this function returns, the caller is free to
6361 * The "destroy" name is only to match the "create" name that this
6362 * should be paired with.
6364 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6366 mutex_lock(&ftrace_lock);
6367 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6368 ftrace_shutdown(ops, 0);
6369 ops->flags |= FTRACE_OPS_FL_DELETED;
6370 ftrace_free_filter(ops);
6371 mutex_unlock(&ftrace_lock);
6374 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6377 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6378 d_tracer, NULL, &ftrace_avail_fops);
6380 trace_create_file("enabled_functions", TRACE_MODE_READ,
6381 d_tracer, NULL, &ftrace_enabled_fops);
6383 trace_create_file("touched_functions", TRACE_MODE_READ,
6384 d_tracer, NULL, &ftrace_touched_fops);
6386 ftrace_create_filter_files(&global_ops, d_tracer);
6388 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6389 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6391 &ftrace_graph_fops);
6392 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6394 &ftrace_graph_notrace_fops);
6395 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6400 static int ftrace_cmp_ips(const void *a, const void *b)
6402 const unsigned long *ipa = a;
6403 const unsigned long *ipb = b;
6412 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6413 static void test_is_sorted(unsigned long *start, unsigned long count)
6417 for (i = 1; i < count; i++) {
6418 if (WARN(start[i - 1] > start[i],
6419 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6420 (void *)start[i - 1], start[i - 1],
6421 (void *)start[i], start[i]))
6425 pr_info("ftrace section at %px sorted properly\n", start);
6428 static void test_is_sorted(unsigned long *start, unsigned long count)
6433 static int ftrace_process_locs(struct module *mod,
6434 unsigned long *start,
6437 struct ftrace_page *start_pg;
6438 struct ftrace_page *pg;
6439 struct dyn_ftrace *rec;
6440 unsigned long count;
6443 unsigned long flags = 0; /* Shut up gcc */
6446 count = end - start;
6452 * Sorting mcount in vmlinux at build time depend on
6453 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6454 * modules can not be sorted at build time.
6456 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6457 sort(start, count, sizeof(*start),
6458 ftrace_cmp_ips, NULL);
6460 test_is_sorted(start, count);
6463 start_pg = ftrace_allocate_pages(count);
6467 mutex_lock(&ftrace_lock);
6470 * Core and each module needs their own pages, as
6471 * modules will free them when they are removed.
6472 * Force a new page to be allocated for modules.
6475 WARN_ON(ftrace_pages || ftrace_pages_start);
6476 /* First initialization */
6477 ftrace_pages = ftrace_pages_start = start_pg;
6482 if (WARN_ON(ftrace_pages->next)) {
6483 /* Hmm, we have free pages? */
6484 while (ftrace_pages->next)
6485 ftrace_pages = ftrace_pages->next;
6488 ftrace_pages->next = start_pg;
6494 unsigned long end_offset;
6495 addr = ftrace_call_adjust(*p++);
6497 * Some architecture linkers will pad between
6498 * the different mcount_loc sections of different
6499 * object files to satisfy alignments.
6500 * Skip any NULL pointers.
6505 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6506 if (end_offset > PAGE_SIZE << pg->order) {
6507 /* We should have allocated enough */
6508 if (WARN_ON(!pg->next))
6513 rec = &pg->records[pg->index++];
6517 /* We should have used all pages */
6520 /* Assign the last page to ftrace_pages */
6524 * We only need to disable interrupts on start up
6525 * because we are modifying code that an interrupt
6526 * may execute, and the modification is not atomic.
6527 * But for modules, nothing runs the code we modify
6528 * until we are finished with it, and there's no
6529 * reason to cause large interrupt latencies while we do it.
6532 local_irq_save(flags);
6533 ftrace_update_code(mod, start_pg);
6535 local_irq_restore(flags);
6538 mutex_unlock(&ftrace_lock);
6543 struct ftrace_mod_func {
6544 struct list_head list;
6550 struct ftrace_mod_map {
6551 struct rcu_head rcu;
6552 struct list_head list;
6554 unsigned long start_addr;
6555 unsigned long end_addr;
6556 struct list_head funcs;
6557 unsigned int num_funcs;
6560 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6561 unsigned long *value, char *type,
6562 char *name, char *module_name,
6565 struct ftrace_ops *op;
6567 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6568 if (!op->trampoline || symnum--)
6570 *value = op->trampoline;
6572 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6573 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6581 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6583 * Check if the current ops references the given ip.
6585 * If the ops traces all functions, then it was already accounted for.
6586 * If the ops does not trace the current record function, skip it.
6587 * If the ops ignores the function via notrace filter, skip it.
6590 ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6592 /* If ops isn't enabled, ignore it */
6593 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6596 /* If ops traces all then it includes this function */
6597 if (ops_traces_mod(ops))
6600 /* The function must be in the filter */
6601 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6602 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6605 /* If in notrace hash, we ignore it too */
6606 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6613 #ifdef CONFIG_MODULES
6615 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6617 static LIST_HEAD(ftrace_mod_maps);
6619 static int referenced_filters(struct dyn_ftrace *rec)
6621 struct ftrace_ops *ops;
6624 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6625 if (ops_references_ip(ops, rec->ip)) {
6626 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6628 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6631 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6632 rec->flags |= FTRACE_FL_REGS;
6633 if (cnt == 1 && ops->trampoline)
6634 rec->flags |= FTRACE_FL_TRAMP;
6636 rec->flags &= ~FTRACE_FL_TRAMP;
6644 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6646 struct ftrace_func_entry *entry;
6647 struct dyn_ftrace *rec;
6650 if (ftrace_hash_empty(hash))
6653 for (i = 0; i < pg->index; i++) {
6654 rec = &pg->records[i];
6655 entry = __ftrace_lookup_ip(hash, rec->ip);
6657 * Do not allow this rec to match again.
6658 * Yeah, it may waste some memory, but will be removed
6659 * if/when the hash is modified again.
6666 /* Clear any records from hashes */
6667 static void clear_mod_from_hashes(struct ftrace_page *pg)
6669 struct trace_array *tr;
6671 mutex_lock(&trace_types_lock);
6672 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6673 if (!tr->ops || !tr->ops->func_hash)
6675 mutex_lock(&tr->ops->func_hash->regex_lock);
6676 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6677 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6678 mutex_unlock(&tr->ops->func_hash->regex_lock);
6680 mutex_unlock(&trace_types_lock);
6683 static void ftrace_free_mod_map(struct rcu_head *rcu)
6685 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6686 struct ftrace_mod_func *mod_func;
6687 struct ftrace_mod_func *n;
6689 /* All the contents of mod_map are now not visible to readers */
6690 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6691 kfree(mod_func->name);
6692 list_del(&mod_func->list);
6699 void ftrace_release_mod(struct module *mod)
6701 struct ftrace_mod_map *mod_map;
6702 struct ftrace_mod_map *n;
6703 struct dyn_ftrace *rec;
6704 struct ftrace_page **last_pg;
6705 struct ftrace_page *tmp_page = NULL;
6706 struct ftrace_page *pg;
6708 mutex_lock(&ftrace_lock);
6710 if (ftrace_disabled)
6713 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6714 if (mod_map->mod == mod) {
6715 list_del_rcu(&mod_map->list);
6716 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6722 * Each module has its own ftrace_pages, remove
6723 * them from the list.
6725 last_pg = &ftrace_pages_start;
6726 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6727 rec = &pg->records[0];
6728 if (within_module_core(rec->ip, mod) ||
6729 within_module_init(rec->ip, mod)) {
6731 * As core pages are first, the first
6732 * page should never be a module page.
6734 if (WARN_ON(pg == ftrace_pages_start))
6737 /* Check if we are deleting the last page */
6738 if (pg == ftrace_pages)
6739 ftrace_pages = next_to_ftrace_page(last_pg);
6741 ftrace_update_tot_cnt -= pg->index;
6742 *last_pg = pg->next;
6744 pg->next = tmp_page;
6747 last_pg = &pg->next;
6750 mutex_unlock(&ftrace_lock);
6752 for (pg = tmp_page; pg; pg = tmp_page) {
6754 /* Needs to be called outside of ftrace_lock */
6755 clear_mod_from_hashes(pg);
6758 free_pages((unsigned long)pg->records, pg->order);
6759 ftrace_number_of_pages -= 1 << pg->order;
6761 tmp_page = pg->next;
6763 ftrace_number_of_groups--;
6767 void ftrace_module_enable(struct module *mod)
6769 struct dyn_ftrace *rec;
6770 struct ftrace_page *pg;
6772 mutex_lock(&ftrace_lock);
6774 if (ftrace_disabled)
6778 * If the tracing is enabled, go ahead and enable the record.
6780 * The reason not to enable the record immediately is the
6781 * inherent check of ftrace_make_nop/ftrace_make_call for
6782 * correct previous instructions. Making first the NOP
6783 * conversion puts the module to the correct state, thus
6784 * passing the ftrace_make_call check.
6786 * We also delay this to after the module code already set the
6787 * text to read-only, as we now need to set it back to read-write
6788 * so that we can modify the text.
6790 if (ftrace_start_up)
6791 ftrace_arch_code_modify_prepare();
6793 do_for_each_ftrace_rec(pg, rec) {
6796 * do_for_each_ftrace_rec() is a double loop.
6797 * module text shares the pg. If a record is
6798 * not part of this module, then skip this pg,
6799 * which the "break" will do.
6801 if (!within_module_core(rec->ip, mod) &&
6802 !within_module_init(rec->ip, mod))
6805 /* Weak functions should still be ignored */
6806 if (!test_for_valid_rec(rec)) {
6807 /* Clear all other flags. Should not be enabled anyway */
6808 rec->flags = FTRACE_FL_DISABLED;
6815 * When adding a module, we need to check if tracers are
6816 * currently enabled and if they are, and can trace this record,
6817 * we need to enable the module functions as well as update the
6818 * reference counts for those function records.
6820 if (ftrace_start_up)
6821 cnt += referenced_filters(rec);
6823 rec->flags &= ~FTRACE_FL_DISABLED;
6826 if (ftrace_start_up && cnt) {
6827 int failed = __ftrace_replace_code(rec, 1);
6829 ftrace_bug(failed, rec);
6834 } while_for_each_ftrace_rec();
6837 if (ftrace_start_up)
6838 ftrace_arch_code_modify_post_process();
6841 mutex_unlock(&ftrace_lock);
6843 process_cached_mods(mod->name);
6846 void ftrace_module_init(struct module *mod)
6850 if (ftrace_disabled || !mod->num_ftrace_callsites)
6853 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6854 mod->ftrace_callsites + mod->num_ftrace_callsites);
6856 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6860 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6861 struct dyn_ftrace *rec)
6863 struct ftrace_mod_func *mod_func;
6864 unsigned long symsize;
6865 unsigned long offset;
6866 char str[KSYM_SYMBOL_LEN];
6870 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6874 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6878 mod_func->name = kstrdup(str, GFP_KERNEL);
6879 if (!mod_func->name) {
6884 mod_func->ip = rec->ip - offset;
6885 mod_func->size = symsize;
6887 mod_map->num_funcs++;
6889 list_add_rcu(&mod_func->list, &mod_map->funcs);
6892 static struct ftrace_mod_map *
6893 allocate_ftrace_mod_map(struct module *mod,
6894 unsigned long start, unsigned long end)
6896 struct ftrace_mod_map *mod_map;
6898 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6903 mod_map->start_addr = start;
6904 mod_map->end_addr = end;
6905 mod_map->num_funcs = 0;
6907 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6909 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6915 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6916 unsigned long addr, unsigned long *size,
6917 unsigned long *off, char *sym)
6919 struct ftrace_mod_func *found_func = NULL;
6920 struct ftrace_mod_func *mod_func;
6922 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6923 if (addr >= mod_func->ip &&
6924 addr < mod_func->ip + mod_func->size) {
6925 found_func = mod_func;
6932 *size = found_func->size;
6934 *off = addr - found_func->ip;
6936 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
6938 return found_func->name;
6945 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6946 unsigned long *off, char **modname, char *sym)
6948 struct ftrace_mod_map *mod_map;
6949 const char *ret = NULL;
6951 /* mod_map is freed via call_rcu() */
6953 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6954 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6957 *modname = mod_map->mod->name;
6966 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6967 char *type, char *name,
6968 char *module_name, int *exported)
6970 struct ftrace_mod_map *mod_map;
6971 struct ftrace_mod_func *mod_func;
6975 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6977 if (symnum >= mod_map->num_funcs) {
6978 symnum -= mod_map->num_funcs;
6982 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6988 *value = mod_func->ip;
6990 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6991 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6999 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7000 module_name, exported);
7006 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7007 struct dyn_ftrace *rec) { }
7008 static inline struct ftrace_mod_map *
7009 allocate_ftrace_mod_map(struct module *mod,
7010 unsigned long start, unsigned long end)
7014 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7015 char *type, char *name, char *module_name,
7021 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7022 module_name, exported);
7026 #endif /* CONFIG_MODULES */
7028 struct ftrace_init_func {
7029 struct list_head list;
7033 /* Clear any init ips from hashes */
7035 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7037 struct ftrace_func_entry *entry;
7039 entry = ftrace_lookup_ip(hash, func->ip);
7041 * Do not allow this rec to match again.
7042 * Yeah, it may waste some memory, but will be removed
7043 * if/when the hash is modified again.
7050 clear_func_from_hashes(struct ftrace_init_func *func)
7052 struct trace_array *tr;
7054 mutex_lock(&trace_types_lock);
7055 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7056 if (!tr->ops || !tr->ops->func_hash)
7058 mutex_lock(&tr->ops->func_hash->regex_lock);
7059 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7060 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7061 mutex_unlock(&tr->ops->func_hash->regex_lock);
7063 mutex_unlock(&trace_types_lock);
7066 static void add_to_clear_hash_list(struct list_head *clear_list,
7067 struct dyn_ftrace *rec)
7069 struct ftrace_init_func *func;
7071 func = kmalloc(sizeof(*func), GFP_KERNEL);
7073 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7078 list_add(&func->list, clear_list);
7081 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7083 unsigned long start = (unsigned long)(start_ptr);
7084 unsigned long end = (unsigned long)(end_ptr);
7085 struct ftrace_page **last_pg = &ftrace_pages_start;
7086 struct ftrace_page *pg;
7087 struct dyn_ftrace *rec;
7088 struct dyn_ftrace key;
7089 struct ftrace_mod_map *mod_map = NULL;
7090 struct ftrace_init_func *func, *func_next;
7091 struct list_head clear_hash;
7093 INIT_LIST_HEAD(&clear_hash);
7096 key.flags = end; /* overload flags, as it is unsigned long */
7098 mutex_lock(&ftrace_lock);
7101 * If we are freeing module init memory, then check if
7102 * any tracer is active. If so, we need to save a mapping of
7103 * the module functions being freed with the address.
7105 if (mod && ftrace_ops_list != &ftrace_list_end)
7106 mod_map = allocate_ftrace_mod_map(mod, start, end);
7108 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7109 if (end < pg->records[0].ip ||
7110 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7113 rec = bsearch(&key, pg->records, pg->index,
7114 sizeof(struct dyn_ftrace),
7119 /* rec will be cleared from hashes after ftrace_lock unlock */
7120 add_to_clear_hash_list(&clear_hash, rec);
7123 save_ftrace_mod_rec(mod_map, rec);
7126 ftrace_update_tot_cnt--;
7128 *last_pg = pg->next;
7130 free_pages((unsigned long)pg->records, pg->order);
7131 ftrace_number_of_pages -= 1 << pg->order;
7133 ftrace_number_of_groups--;
7135 pg = container_of(last_pg, struct ftrace_page, next);
7140 memmove(rec, rec + 1,
7141 (pg->index - (rec - pg->records)) * sizeof(*rec));
7142 /* More than one function may be in this block */
7145 mutex_unlock(&ftrace_lock);
7147 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7148 clear_func_from_hashes(func);
7153 void __init ftrace_free_init_mem(void)
7155 void *start = (void *)(&__init_begin);
7156 void *end = (void *)(&__init_end);
7158 ftrace_boot_snapshot();
7160 ftrace_free_mem(NULL, start, end);
7163 int __init __weak ftrace_dyn_arch_init(void)
7168 void __init ftrace_init(void)
7170 extern unsigned long __start_mcount_loc[];
7171 extern unsigned long __stop_mcount_loc[];
7172 unsigned long count, flags;
7175 local_irq_save(flags);
7176 ret = ftrace_dyn_arch_init();
7177 local_irq_restore(flags);
7181 count = __stop_mcount_loc - __start_mcount_loc;
7183 pr_info("ftrace: No functions to be traced?\n");
7187 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7188 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7190 ret = ftrace_process_locs(NULL,
7194 pr_warn("ftrace: failed to allocate entries for functions\n");
7198 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7199 ftrace_number_of_pages, ftrace_number_of_groups);
7201 last_ftrace_enabled = ftrace_enabled = 1;
7203 set_ftrace_early_filters();
7207 ftrace_disabled = 1;
7210 /* Do nothing if arch does not support this */
7211 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7215 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7217 unsigned long trampoline = ops->trampoline;
7219 arch_ftrace_update_trampoline(ops);
7220 if (ops->trampoline && ops->trampoline != trampoline &&
7221 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7222 /* Add to kallsyms before the perf events */
7223 ftrace_add_trampoline_to_kallsyms(ops);
7224 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7225 ops->trampoline, ops->trampoline_size, false,
7226 FTRACE_TRAMPOLINE_SYM);
7228 * Record the perf text poke event after the ksymbol register
7231 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7232 (void *)ops->trampoline,
7233 ops->trampoline_size);
7237 void ftrace_init_trace_array(struct trace_array *tr)
7239 INIT_LIST_HEAD(&tr->func_probes);
7240 INIT_LIST_HEAD(&tr->mod_trace);
7241 INIT_LIST_HEAD(&tr->mod_notrace);
7245 struct ftrace_ops global_ops = {
7246 .func = ftrace_stub,
7247 .flags = FTRACE_OPS_FL_INITIALIZED |
7251 static int __init ftrace_nodyn_init(void)
7256 core_initcall(ftrace_nodyn_init);
7258 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7259 static inline void ftrace_startup_all(int command) { }
7261 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7265 #endif /* CONFIG_DYNAMIC_FTRACE */
7267 __init void ftrace_init_global_array_ops(struct trace_array *tr)
7269 tr->ops = &global_ops;
7270 tr->ops->private = tr;
7271 ftrace_init_trace_array(tr);
7274 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7276 /* If we filter on pids, update to use the pid function */
7277 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7278 if (WARN_ON(tr->ops->func != ftrace_stub))
7279 printk("ftrace ops had %pS for function\n",
7282 tr->ops->func = func;
7283 tr->ops->private = tr;
7286 void ftrace_reset_array_ops(struct trace_array *tr)
7288 tr->ops->func = ftrace_stub;
7291 static nokprobe_inline void
7292 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7293 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7295 struct pt_regs *regs = ftrace_get_regs(fregs);
7296 struct ftrace_ops *op;
7300 * The ftrace_test_and_set_recursion() will disable preemption,
7301 * which is required since some of the ops may be dynamically
7302 * allocated, they must be freed after a synchronize_rcu().
7304 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7308 do_for_each_ftrace_op(op, ftrace_ops_list) {
7309 /* Stub functions don't need to be called nor tested */
7310 if (op->flags & FTRACE_OPS_FL_STUB)
7313 * Check the following for each ops before calling their func:
7314 * if RCU flag is set, then rcu_is_watching() must be true
7315 * Otherwise test if the ip matches the ops filter
7317 * If any of the above fails then the op->func() is not executed.
7319 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7320 ftrace_ops_test(op, ip, regs)) {
7321 if (FTRACE_WARN_ON(!op->func)) {
7322 pr_warn("op=%p %pS\n", op, op);
7325 op->func(ip, parent_ip, op, fregs);
7327 } while_for_each_ftrace_op(op);
7329 trace_clear_recursion(bit);
7333 * Some archs only support passing ip and parent_ip. Even though
7334 * the list function ignores the op parameter, we do not want any
7335 * C side effects, where a function is called without the caller
7336 * sending a third parameter.
7337 * Archs are to support both the regs and ftrace_ops at the same time.
7338 * If they support ftrace_ops, it is assumed they support regs.
7339 * If call backs want to use regs, they must either check for regs
7340 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7341 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7342 * An architecture can pass partial regs with ftrace_ops and still
7343 * set the ARCH_SUPPORTS_FTRACE_OPS.
7345 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7346 * arch_ftrace_ops_list_func.
7348 #if ARCH_SUPPORTS_FTRACE_OPS
7349 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7350 struct ftrace_ops *op, struct ftrace_regs *fregs)
7352 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7355 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7357 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7360 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7363 * If there's only one function registered but it does not support
7364 * recursion, needs RCU protection, then this function will be called
7365 * by the mcount trampoline.
7367 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7368 struct ftrace_ops *op, struct ftrace_regs *fregs)
7372 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7376 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7377 op->func(ip, parent_ip, op, fregs);
7379 trace_clear_recursion(bit);
7381 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7384 * ftrace_ops_get_func - get the function a trampoline should call
7385 * @ops: the ops to get the function for
7387 * Normally the mcount trampoline will call the ops->func, but there
7388 * are times that it should not. For example, if the ops does not
7389 * have its own recursion protection, then it should call the
7390 * ftrace_ops_assist_func() instead.
7392 * Returns the function that the trampoline should call for @ops.
7394 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7397 * If the function does not handle recursion or needs to be RCU safe,
7398 * then we need to call the assist handler.
7400 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7402 return ftrace_ops_assist_func;
7408 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7409 struct task_struct *prev,
7410 struct task_struct *next,
7411 unsigned int prev_state)
7413 struct trace_array *tr = data;
7414 struct trace_pid_list *pid_list;
7415 struct trace_pid_list *no_pid_list;
7417 pid_list = rcu_dereference_sched(tr->function_pids);
7418 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7420 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7421 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7424 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7429 ftrace_pid_follow_sched_process_fork(void *data,
7430 struct task_struct *self,
7431 struct task_struct *task)
7433 struct trace_pid_list *pid_list;
7434 struct trace_array *tr = data;
7436 pid_list = rcu_dereference_sched(tr->function_pids);
7437 trace_filter_add_remove_task(pid_list, self, task);
7439 pid_list = rcu_dereference_sched(tr->function_no_pids);
7440 trace_filter_add_remove_task(pid_list, self, task);
7444 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7446 struct trace_pid_list *pid_list;
7447 struct trace_array *tr = data;
7449 pid_list = rcu_dereference_sched(tr->function_pids);
7450 trace_filter_add_remove_task(pid_list, NULL, task);
7452 pid_list = rcu_dereference_sched(tr->function_no_pids);
7453 trace_filter_add_remove_task(pid_list, NULL, task);
7456 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7459 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7461 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7464 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7466 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7471 static void clear_ftrace_pids(struct trace_array *tr, int type)
7473 struct trace_pid_list *pid_list;
7474 struct trace_pid_list *no_pid_list;
7477 pid_list = rcu_dereference_protected(tr->function_pids,
7478 lockdep_is_held(&ftrace_lock));
7479 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7480 lockdep_is_held(&ftrace_lock));
7482 /* Make sure there's something to do */
7483 if (!pid_type_enabled(type, pid_list, no_pid_list))
7486 /* See if the pids still need to be checked after this */
7487 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7488 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7489 for_each_possible_cpu(cpu)
7490 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7493 if (type & TRACE_PIDS)
7494 rcu_assign_pointer(tr->function_pids, NULL);
7496 if (type & TRACE_NO_PIDS)
7497 rcu_assign_pointer(tr->function_no_pids, NULL);
7499 /* Wait till all users are no longer using pid filtering */
7502 if ((type & TRACE_PIDS) && pid_list)
7503 trace_pid_list_free(pid_list);
7505 if ((type & TRACE_NO_PIDS) && no_pid_list)
7506 trace_pid_list_free(no_pid_list);
7509 void ftrace_clear_pids(struct trace_array *tr)
7511 mutex_lock(&ftrace_lock);
7513 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7515 mutex_unlock(&ftrace_lock);
7518 static void ftrace_pid_reset(struct trace_array *tr, int type)
7520 mutex_lock(&ftrace_lock);
7521 clear_ftrace_pids(tr, type);
7523 ftrace_update_pid_func();
7524 ftrace_startup_all(0);
7526 mutex_unlock(&ftrace_lock);
7529 /* Greater than any max PID */
7530 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7532 static void *fpid_start(struct seq_file *m, loff_t *pos)
7535 struct trace_pid_list *pid_list;
7536 struct trace_array *tr = m->private;
7538 mutex_lock(&ftrace_lock);
7539 rcu_read_lock_sched();
7541 pid_list = rcu_dereference_sched(tr->function_pids);
7544 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7546 return trace_pid_start(pid_list, pos);
7549 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7551 struct trace_array *tr = m->private;
7552 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7554 if (v == FTRACE_NO_PIDS) {
7558 return trace_pid_next(pid_list, v, pos);
7561 static void fpid_stop(struct seq_file *m, void *p)
7564 rcu_read_unlock_sched();
7565 mutex_unlock(&ftrace_lock);
7568 static int fpid_show(struct seq_file *m, void *v)
7570 if (v == FTRACE_NO_PIDS) {
7571 seq_puts(m, "no pid\n");
7575 return trace_pid_show(m, v);
7578 static const struct seq_operations ftrace_pid_sops = {
7579 .start = fpid_start,
7585 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7588 struct trace_pid_list *pid_list;
7589 struct trace_array *tr = m->private;
7591 mutex_lock(&ftrace_lock);
7592 rcu_read_lock_sched();
7594 pid_list = rcu_dereference_sched(tr->function_no_pids);
7597 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7599 return trace_pid_start(pid_list, pos);
7602 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7604 struct trace_array *tr = m->private;
7605 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7607 if (v == FTRACE_NO_PIDS) {
7611 return trace_pid_next(pid_list, v, pos);
7614 static const struct seq_operations ftrace_no_pid_sops = {
7615 .start = fnpid_start,
7621 static int pid_open(struct inode *inode, struct file *file, int type)
7623 const struct seq_operations *seq_ops;
7624 struct trace_array *tr = inode->i_private;
7628 ret = tracing_check_open_get_tr(tr);
7632 if ((file->f_mode & FMODE_WRITE) &&
7633 (file->f_flags & O_TRUNC))
7634 ftrace_pid_reset(tr, type);
7638 seq_ops = &ftrace_pid_sops;
7641 seq_ops = &ftrace_no_pid_sops;
7644 trace_array_put(tr);
7649 ret = seq_open(file, seq_ops);
7651 trace_array_put(tr);
7653 m = file->private_data;
7654 /* copy tr over to seq ops */
7662 ftrace_pid_open(struct inode *inode, struct file *file)
7664 return pid_open(inode, file, TRACE_PIDS);
7668 ftrace_no_pid_open(struct inode *inode, struct file *file)
7670 return pid_open(inode, file, TRACE_NO_PIDS);
7673 static void ignore_task_cpu(void *data)
7675 struct trace_array *tr = data;
7676 struct trace_pid_list *pid_list;
7677 struct trace_pid_list *no_pid_list;
7680 * This function is called by on_each_cpu() while the
7681 * event_mutex is held.
7683 pid_list = rcu_dereference_protected(tr->function_pids,
7684 mutex_is_locked(&ftrace_lock));
7685 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7686 mutex_is_locked(&ftrace_lock));
7688 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7689 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7692 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7697 pid_write(struct file *filp, const char __user *ubuf,
7698 size_t cnt, loff_t *ppos, int type)
7700 struct seq_file *m = filp->private_data;
7701 struct trace_array *tr = m->private;
7702 struct trace_pid_list *filtered_pids;
7703 struct trace_pid_list *other_pids;
7704 struct trace_pid_list *pid_list;
7710 mutex_lock(&ftrace_lock);
7714 filtered_pids = rcu_dereference_protected(tr->function_pids,
7715 lockdep_is_held(&ftrace_lock));
7716 other_pids = rcu_dereference_protected(tr->function_no_pids,
7717 lockdep_is_held(&ftrace_lock));
7720 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7721 lockdep_is_held(&ftrace_lock));
7722 other_pids = rcu_dereference_protected(tr->function_pids,
7723 lockdep_is_held(&ftrace_lock));
7731 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7737 rcu_assign_pointer(tr->function_pids, pid_list);
7740 rcu_assign_pointer(tr->function_no_pids, pid_list);
7745 if (filtered_pids) {
7747 trace_pid_list_free(filtered_pids);
7748 } else if (pid_list && !other_pids) {
7749 /* Register a probe to set whether to ignore the tracing of a task */
7750 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7754 * Ignoring of pids is done at task switch. But we have to
7755 * check for those tasks that are currently running.
7756 * Always do this in case a pid was appended or removed.
7758 on_each_cpu(ignore_task_cpu, tr, 1);
7760 ftrace_update_pid_func();
7761 ftrace_startup_all(0);
7763 mutex_unlock(&ftrace_lock);
7772 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7773 size_t cnt, loff_t *ppos)
7775 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7779 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7780 size_t cnt, loff_t *ppos)
7782 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7786 ftrace_pid_release(struct inode *inode, struct file *file)
7788 struct trace_array *tr = inode->i_private;
7790 trace_array_put(tr);
7792 return seq_release(inode, file);
7795 static const struct file_operations ftrace_pid_fops = {
7796 .open = ftrace_pid_open,
7797 .write = ftrace_pid_write,
7799 .llseek = tracing_lseek,
7800 .release = ftrace_pid_release,
7803 static const struct file_operations ftrace_no_pid_fops = {
7804 .open = ftrace_no_pid_open,
7805 .write = ftrace_no_pid_write,
7807 .llseek = tracing_lseek,
7808 .release = ftrace_pid_release,
7811 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7813 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7814 tr, &ftrace_pid_fops);
7815 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7816 d_tracer, tr, &ftrace_no_pid_fops);
7819 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7820 struct dentry *d_tracer)
7822 /* Only the top level directory has the dyn_tracefs and profile */
7823 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7825 ftrace_init_dyn_tracefs(d_tracer);
7826 ftrace_profile_tracefs(d_tracer);
7830 * ftrace_kill - kill ftrace
7832 * This function should be used by panic code. It stops ftrace
7833 * but in a not so nice way. If you need to simply kill ftrace
7834 * from a non-atomic section, use ftrace_kill.
7836 void ftrace_kill(void)
7838 ftrace_disabled = 1;
7840 ftrace_trace_function = ftrace_stub;
7844 * ftrace_is_dead - Test if ftrace is dead or not.
7846 * Returns 1 if ftrace is "dead", zero otherwise.
7848 int ftrace_is_dead(void)
7850 return ftrace_disabled;
7853 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7855 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7856 * it doesn't conflict with any direct ftrace_ops. If there is existing
7857 * direct ftrace_ops on a kernel function being patched, call
7858 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7860 * @ops: ftrace_ops being registered.
7864 * Negative on failure.
7866 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7868 struct ftrace_func_entry *entry;
7869 struct ftrace_hash *hash;
7870 struct ftrace_ops *op;
7873 lockdep_assert_held_once(&direct_mutex);
7875 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7878 hash = ops->func_hash->filter_hash;
7879 size = 1 << hash->size_bits;
7880 for (i = 0; i < size; i++) {
7881 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7882 unsigned long ip = entry->ip;
7883 bool found_op = false;
7885 mutex_lock(&ftrace_lock);
7886 do_for_each_ftrace_op(op, ftrace_ops_list) {
7887 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7889 if (ops_references_ip(op, ip)) {
7893 } while_for_each_ftrace_op(op);
7894 mutex_unlock(&ftrace_lock);
7900 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7911 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7912 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7915 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7917 struct ftrace_func_entry *entry;
7918 struct ftrace_hash *hash;
7919 struct ftrace_ops *op;
7922 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7925 mutex_lock(&direct_mutex);
7927 hash = ops->func_hash->filter_hash;
7928 size = 1 << hash->size_bits;
7929 for (i = 0; i < size; i++) {
7930 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7931 unsigned long ip = entry->ip;
7932 bool found_op = false;
7934 mutex_lock(&ftrace_lock);
7935 do_for_each_ftrace_op(op, ftrace_ops_list) {
7936 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7938 if (ops_references_ip(op, ip)) {
7942 } while_for_each_ftrace_op(op);
7943 mutex_unlock(&ftrace_lock);
7945 /* The cleanup is optional, ignore any errors */
7946 if (found_op && op->ops_func)
7947 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
7950 mutex_unlock(&direct_mutex);
7953 #define lock_direct_mutex() mutex_lock(&direct_mutex)
7954 #define unlock_direct_mutex() mutex_unlock(&direct_mutex)
7956 #else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
7958 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7963 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7967 #define lock_direct_mutex() do { } while (0)
7968 #define unlock_direct_mutex() do { } while (0)
7970 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
7973 * Similar to register_ftrace_function, except we don't lock direct_mutex.
7975 static int register_ftrace_function_nolock(struct ftrace_ops *ops)
7979 ftrace_ops_init(ops);
7981 mutex_lock(&ftrace_lock);
7983 ret = ftrace_startup(ops, 0);
7985 mutex_unlock(&ftrace_lock);
7991 * register_ftrace_function - register a function for profiling
7992 * @ops: ops structure that holds the function for profiling.
7994 * Register a function to be called by all functions in the
7997 * Note: @ops->func and all the functions it calls must be labeled
7998 * with "notrace", otherwise it will go into a
8001 int register_ftrace_function(struct ftrace_ops *ops)
8005 lock_direct_mutex();
8006 ret = prepare_direct_functions_for_ipmodify(ops);
8010 ret = register_ftrace_function_nolock(ops);
8013 unlock_direct_mutex();
8016 EXPORT_SYMBOL_GPL(register_ftrace_function);
8019 * unregister_ftrace_function - unregister a function for profiling.
8020 * @ops: ops structure that holds the function to unregister
8022 * Unregister a function that was added to be called by ftrace profiling.
8024 int unregister_ftrace_function(struct ftrace_ops *ops)
8028 mutex_lock(&ftrace_lock);
8029 ret = ftrace_shutdown(ops, 0);
8030 mutex_unlock(&ftrace_lock);
8032 cleanup_direct_functions_after_ipmodify(ops);
8035 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8037 static int symbols_cmp(const void *a, const void *b)
8039 const char **str_a = (const char **) a;
8040 const char **str_b = (const char **) b;
8042 return strcmp(*str_a, *str_b);
8045 struct kallsyms_data {
8046 unsigned long *addrs;
8052 /* This function gets called for all kernel and module symbols
8053 * and returns 1 in case we resolved all the requested symbols,
8056 static int kallsyms_callback(void *data, const char *name, unsigned long addr)
8058 struct kallsyms_data *args = data;
8062 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8066 idx = sym - args->syms;
8067 if (args->addrs[idx])
8070 if (!ftrace_location(addr))
8073 args->addrs[idx] = addr;
8075 return args->found == args->cnt ? 1 : 0;
8079 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8081 * @sorted_syms: array of symbols pointers symbols to resolve,
8082 * must be alphabetically sorted
8083 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8084 * @addrs: array for storing resulting addresses
8086 * This function looks up addresses for array of symbols provided in
8087 * @syms array (must be alphabetically sorted) and stores them in
8088 * @addrs array, which needs to be big enough to store at least @cnt
8091 * This function returns 0 if all provided symbols are found,
8094 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8096 struct kallsyms_data args;
8099 memset(addrs, 0, sizeof(*addrs) * cnt);
8101 args.syms = sorted_syms;
8105 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8108 found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8109 return found_all ? 0 : -ESRCH;
8112 #ifdef CONFIG_SYSCTL
8114 #ifdef CONFIG_DYNAMIC_FTRACE
8115 static void ftrace_startup_sysctl(void)
8119 if (unlikely(ftrace_disabled))
8122 /* Force update next time */
8123 saved_ftrace_func = NULL;
8124 /* ftrace_start_up is true if we want ftrace running */
8125 if (ftrace_start_up) {
8126 command = FTRACE_UPDATE_CALLS;
8127 if (ftrace_graph_active)
8128 command |= FTRACE_START_FUNC_RET;
8129 ftrace_startup_enable(command);
8133 static void ftrace_shutdown_sysctl(void)
8137 if (unlikely(ftrace_disabled))
8140 /* ftrace_start_up is true if ftrace is running */
8141 if (ftrace_start_up) {
8142 command = FTRACE_DISABLE_CALLS;
8143 if (ftrace_graph_active)
8144 command |= FTRACE_STOP_FUNC_RET;
8145 ftrace_run_update_code(command);
8149 # define ftrace_startup_sysctl() do { } while (0)
8150 # define ftrace_shutdown_sysctl() do { } while (0)
8151 #endif /* CONFIG_DYNAMIC_FTRACE */
8153 static bool is_permanent_ops_registered(void)
8155 struct ftrace_ops *op;
8157 do_for_each_ftrace_op(op, ftrace_ops_list) {
8158 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8160 } while_for_each_ftrace_op(op);
8166 ftrace_enable_sysctl(struct ctl_table *table, int write,
8167 void *buffer, size_t *lenp, loff_t *ppos)
8171 mutex_lock(&ftrace_lock);
8173 if (unlikely(ftrace_disabled))
8176 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8178 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8181 if (ftrace_enabled) {
8183 /* we are starting ftrace again */
8184 if (rcu_dereference_protected(ftrace_ops_list,
8185 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8186 update_ftrace_function();
8188 ftrace_startup_sysctl();
8191 if (is_permanent_ops_registered()) {
8192 ftrace_enabled = true;
8197 /* stopping ftrace calls (just send to ftrace_stub) */
8198 ftrace_trace_function = ftrace_stub;
8200 ftrace_shutdown_sysctl();
8203 last_ftrace_enabled = !!ftrace_enabled;
8205 mutex_unlock(&ftrace_lock);
8209 static struct ctl_table ftrace_sysctls[] = {
8211 .procname = "ftrace_enabled",
8212 .data = &ftrace_enabled,
8213 .maxlen = sizeof(int),
8215 .proc_handler = ftrace_enable_sysctl,
8220 static int __init ftrace_sysctl_init(void)
8222 register_sysctl_init("kernel", ftrace_sysctls);
8225 late_initcall(ftrace_sysctl_init);