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 (iter->flags & FTRACE_ITER_ADDRS)
3865 seq_printf(m, "%lx ", rec->ip);
3867 if (print_rec(m, rec->ip)) {
3868 /* This should only happen when a rec is disabled */
3869 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3874 if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3875 struct ftrace_ops *ops;
3877 seq_printf(m, " (%ld)%s%s%s%s%s",
3878 ftrace_rec_count(rec),
3879 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3880 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3881 rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
3882 rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
3883 rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
3884 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3885 ops = ftrace_find_tramp_ops_any(rec);
3888 seq_printf(m, "\ttramp: %pS (%pS)",
3889 (void *)ops->trampoline,
3891 add_trampoline_func(m, ops, rec);
3892 ops = ftrace_find_tramp_ops_next(rec, ops);
3895 seq_puts(m, "\ttramp: ERROR!");
3897 add_trampoline_func(m, NULL, rec);
3899 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3900 ops = ftrace_find_unique_ops(rec);
3902 seq_printf(m, "\tops: %pS (%pS)",
3905 seq_puts(m, "\tops: ERROR!");
3908 if (rec->flags & FTRACE_FL_DIRECT) {
3909 unsigned long direct;
3911 direct = ftrace_find_rec_direct(rec->ip);
3913 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3922 static const struct seq_operations show_ftrace_seq_ops = {
3930 ftrace_avail_open(struct inode *inode, struct file *file)
3932 struct ftrace_iterator *iter;
3935 ret = security_locked_down(LOCKDOWN_TRACEFS);
3939 if (unlikely(ftrace_disabled))
3942 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3946 iter->pg = ftrace_pages_start;
3947 iter->ops = &global_ops;
3953 ftrace_enabled_open(struct inode *inode, struct file *file)
3955 struct ftrace_iterator *iter;
3958 * This shows us what functions are currently being
3959 * traced and by what. Not sure if we want lockdown
3960 * to hide such critical information for an admin.
3961 * Although, perhaps it can show information we don't
3962 * want people to see, but if something is tracing
3963 * something, we probably want to know about it.
3966 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3970 iter->pg = ftrace_pages_start;
3971 iter->flags = FTRACE_ITER_ENABLED;
3972 iter->ops = &global_ops;
3978 ftrace_touched_open(struct inode *inode, struct file *file)
3980 struct ftrace_iterator *iter;
3983 * This shows us what functions have ever been enabled
3984 * (traced, direct, patched, etc). Not sure if we want lockdown
3985 * to hide such critical information for an admin.
3986 * Although, perhaps it can show information we don't
3987 * want people to see, but if something had traced
3988 * something, we probably want to know about it.
3991 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3995 iter->pg = ftrace_pages_start;
3996 iter->flags = FTRACE_ITER_TOUCHED;
3997 iter->ops = &global_ops;
4003 ftrace_avail_addrs_open(struct inode *inode, struct file *file)
4005 struct ftrace_iterator *iter;
4008 ret = security_locked_down(LOCKDOWN_TRACEFS);
4012 if (unlikely(ftrace_disabled))
4015 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
4019 iter->pg = ftrace_pages_start;
4020 iter->flags = FTRACE_ITER_ADDRS;
4021 iter->ops = &global_ops;
4027 * ftrace_regex_open - initialize function tracer filter files
4028 * @ops: The ftrace_ops that hold the hash filters
4029 * @flag: The type of filter to process
4030 * @inode: The inode, usually passed in to your open routine
4031 * @file: The file, usually passed in to your open routine
4033 * ftrace_regex_open() initializes the filter files for the
4034 * @ops. Depending on @flag it may process the filter hash or
4035 * the notrace hash of @ops. With this called from the open
4036 * routine, you can use ftrace_filter_write() for the write
4037 * routine if @flag has FTRACE_ITER_FILTER set, or
4038 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4039 * tracing_lseek() should be used as the lseek routine, and
4040 * release must call ftrace_regex_release().
4043 ftrace_regex_open(struct ftrace_ops *ops, int flag,
4044 struct inode *inode, struct file *file)
4046 struct ftrace_iterator *iter;
4047 struct ftrace_hash *hash;
4048 struct list_head *mod_head;
4049 struct trace_array *tr = ops->private;
4052 ftrace_ops_init(ops);
4054 if (unlikely(ftrace_disabled))
4057 if (tracing_check_open_get_tr(tr))
4060 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4064 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4071 mutex_lock(&ops->func_hash->regex_lock);
4073 if (flag & FTRACE_ITER_NOTRACE) {
4074 hash = ops->func_hash->notrace_hash;
4075 mod_head = tr ? &tr->mod_notrace : NULL;
4077 hash = ops->func_hash->filter_hash;
4078 mod_head = tr ? &tr->mod_trace : NULL;
4081 iter->mod_list = mod_head;
4083 if (file->f_mode & FMODE_WRITE) {
4084 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4086 if (file->f_flags & O_TRUNC) {
4087 iter->hash = alloc_ftrace_hash(size_bits);
4088 clear_ftrace_mod_list(mod_head);
4090 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4094 trace_parser_put(&iter->parser);
4102 if (file->f_mode & FMODE_READ) {
4103 iter->pg = ftrace_pages_start;
4105 ret = seq_open(file, &show_ftrace_seq_ops);
4107 struct seq_file *m = file->private_data;
4111 free_ftrace_hash(iter->hash);
4112 trace_parser_put(&iter->parser);
4115 file->private_data = iter;
4118 mutex_unlock(&ops->func_hash->regex_lock);
4124 trace_array_put(tr);
4131 ftrace_filter_open(struct inode *inode, struct file *file)
4133 struct ftrace_ops *ops = inode->i_private;
4135 /* Checks for tracefs lockdown */
4136 return ftrace_regex_open(ops,
4137 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4142 ftrace_notrace_open(struct inode *inode, struct file *file)
4144 struct ftrace_ops *ops = inode->i_private;
4146 /* Checks for tracefs lockdown */
4147 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4151 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4152 struct ftrace_glob {
4159 * If symbols in an architecture don't correspond exactly to the user-visible
4160 * name of what they represent, it is possible to define this function to
4161 * perform the necessary adjustments.
4163 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4168 static int ftrace_match(char *str, struct ftrace_glob *g)
4173 str = arch_ftrace_match_adjust(str, g->search);
4177 if (strcmp(str, g->search) == 0)
4180 case MATCH_FRONT_ONLY:
4181 if (strncmp(str, g->search, g->len) == 0)
4184 case MATCH_MIDDLE_ONLY:
4185 if (strstr(str, g->search))
4188 case MATCH_END_ONLY:
4190 if (slen >= g->len &&
4191 memcmp(str + slen - g->len, g->search, g->len) == 0)
4195 if (glob_match(g->search, str))
4204 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4206 struct ftrace_func_entry *entry;
4209 entry = ftrace_lookup_ip(hash, rec->ip);
4211 /* Do nothing if it doesn't exist */
4215 free_hash_entry(hash, entry);
4217 /* Do nothing if it exists */
4221 ret = add_hash_entry(hash, rec->ip);
4227 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4230 long index = simple_strtoul(func_g->search, NULL, 0);
4231 struct ftrace_page *pg;
4232 struct dyn_ftrace *rec;
4234 /* The index starts at 1 */
4238 do_for_each_ftrace_rec(pg, rec) {
4239 if (pg->index <= index) {
4241 /* this is a double loop, break goes to the next page */
4244 rec = &pg->records[index];
4245 enter_record(hash, rec, clear_filter);
4247 } while_for_each_ftrace_rec();
4251 #ifdef FTRACE_MCOUNT_MAX_OFFSET
4252 static int lookup_ip(unsigned long ip, char **modname, char *str)
4254 unsigned long offset;
4256 kallsyms_lookup(ip, NULL, &offset, modname, str);
4257 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4262 static int lookup_ip(unsigned long ip, char **modname, char *str)
4264 kallsyms_lookup(ip, NULL, NULL, modname, str);
4270 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4271 struct ftrace_glob *mod_g, int exclude_mod)
4273 char str[KSYM_SYMBOL_LEN];
4276 if (lookup_ip(rec->ip, &modname, str)) {
4277 /* This should only happen when a rec is disabled */
4278 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4279 !(rec->flags & FTRACE_FL_DISABLED));
4284 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4286 /* blank module name to match all modules */
4288 /* blank module globbing: modname xor exclude_mod */
4289 if (!exclude_mod != !modname)
4295 * exclude_mod is set to trace everything but the given
4296 * module. If it is set and the module matches, then
4297 * return 0. If it is not set, and the module doesn't match
4298 * also return 0. Otherwise, check the function to see if
4301 if (!mod_matches == !exclude_mod)
4304 /* blank search means to match all funcs in the mod */
4309 return ftrace_match(str, func_g);
4313 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4315 struct ftrace_page *pg;
4316 struct dyn_ftrace *rec;
4317 struct ftrace_glob func_g = { .type = MATCH_FULL };
4318 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4319 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4320 int exclude_mod = 0;
4323 int clear_filter = 0;
4326 func_g.type = filter_parse_regex(func, len, &func_g.search,
4328 func_g.len = strlen(func_g.search);
4332 mod_g.type = filter_parse_regex(mod, strlen(mod),
4333 &mod_g.search, &exclude_mod);
4334 mod_g.len = strlen(mod_g.search);
4337 mutex_lock(&ftrace_lock);
4339 if (unlikely(ftrace_disabled))
4342 if (func_g.type == MATCH_INDEX) {
4343 found = add_rec_by_index(hash, &func_g, clear_filter);
4347 do_for_each_ftrace_rec(pg, rec) {
4349 if (rec->flags & FTRACE_FL_DISABLED)
4352 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4353 ret = enter_record(hash, rec, clear_filter);
4361 } while_for_each_ftrace_rec();
4363 mutex_unlock(&ftrace_lock);
4369 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4371 return match_records(hash, buff, len, NULL);
4374 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4375 struct ftrace_ops_hash *old_hash)
4377 struct ftrace_ops *op;
4379 if (!ftrace_enabled)
4382 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4383 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4388 * If this is the shared global_ops filter, then we need to
4389 * check if there is another ops that shares it, is enabled.
4390 * If so, we still need to run the modify code.
4392 if (ops->func_hash != &global_ops.local_hash)
4395 do_for_each_ftrace_op(op, ftrace_ops_list) {
4396 if (op->func_hash == &global_ops.local_hash &&
4397 op->flags & FTRACE_OPS_FL_ENABLED) {
4398 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4399 /* Only need to do this once */
4402 } while_for_each_ftrace_op(op);
4405 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4406 struct ftrace_hash **orig_hash,
4407 struct ftrace_hash *hash,
4410 struct ftrace_ops_hash old_hash_ops;
4411 struct ftrace_hash *old_hash;
4414 old_hash = *orig_hash;
4415 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4416 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4417 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4419 ftrace_ops_update_code(ops, &old_hash_ops);
4420 free_ftrace_hash_rcu(old_hash);
4425 static bool module_exists(const char *module)
4427 /* All modules have the symbol __this_module */
4428 static const char this_mod[] = "__this_module";
4429 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4433 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4435 if (n > sizeof(modname) - 1)
4438 val = module_kallsyms_lookup_name(modname);
4442 static int cache_mod(struct trace_array *tr,
4443 const char *func, char *module, int enable)
4445 struct ftrace_mod_load *ftrace_mod, *n;
4446 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4449 mutex_lock(&ftrace_lock);
4451 /* We do not cache inverse filters */
4452 if (func[0] == '!') {
4456 /* Look to remove this hash */
4457 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4458 if (strcmp(ftrace_mod->module, module) != 0)
4461 /* no func matches all */
4462 if (strcmp(func, "*") == 0 ||
4463 (ftrace_mod->func &&
4464 strcmp(ftrace_mod->func, func) == 0)) {
4466 free_ftrace_mod(ftrace_mod);
4474 /* We only care about modules that have not been loaded yet */
4475 if (module_exists(module))
4478 /* Save this string off, and execute it when the module is loaded */
4479 ret = ftrace_add_mod(tr, func, module, enable);
4481 mutex_unlock(&ftrace_lock);
4487 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4488 int reset, int enable);
4490 #ifdef CONFIG_MODULES
4491 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4492 char *mod, bool enable)
4494 struct ftrace_mod_load *ftrace_mod, *n;
4495 struct ftrace_hash **orig_hash, *new_hash;
4496 LIST_HEAD(process_mods);
4499 mutex_lock(&ops->func_hash->regex_lock);
4502 orig_hash = &ops->func_hash->filter_hash;
4504 orig_hash = &ops->func_hash->notrace_hash;
4506 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4509 goto out; /* warn? */
4511 mutex_lock(&ftrace_lock);
4513 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4515 if (strcmp(ftrace_mod->module, mod) != 0)
4518 if (ftrace_mod->func)
4519 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4521 func = kstrdup("*", GFP_KERNEL);
4523 if (!func) /* warn? */
4526 list_move(&ftrace_mod->list, &process_mods);
4528 /* Use the newly allocated func, as it may be "*" */
4529 kfree(ftrace_mod->func);
4530 ftrace_mod->func = func;
4533 mutex_unlock(&ftrace_lock);
4535 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4537 func = ftrace_mod->func;
4539 /* Grabs ftrace_lock, which is why we have this extra step */
4540 match_records(new_hash, func, strlen(func), mod);
4541 free_ftrace_mod(ftrace_mod);
4544 if (enable && list_empty(head))
4545 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4547 mutex_lock(&ftrace_lock);
4549 ftrace_hash_move_and_update_ops(ops, orig_hash,
4551 mutex_unlock(&ftrace_lock);
4554 mutex_unlock(&ops->func_hash->regex_lock);
4556 free_ftrace_hash(new_hash);
4559 static void process_cached_mods(const char *mod_name)
4561 struct trace_array *tr;
4564 mod = kstrdup(mod_name, GFP_KERNEL);
4568 mutex_lock(&trace_types_lock);
4569 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4570 if (!list_empty(&tr->mod_trace))
4571 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4572 if (!list_empty(&tr->mod_notrace))
4573 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4575 mutex_unlock(&trace_types_lock);
4582 * We register the module command as a template to show others how
4583 * to register the a command as well.
4587 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4588 char *func_orig, char *cmd, char *module, int enable)
4593 /* match_records() modifies func, and we need the original */
4594 func = kstrdup(func_orig, GFP_KERNEL);
4599 * cmd == 'mod' because we only registered this func
4600 * for the 'mod' ftrace_func_command.
4601 * But if you register one func with multiple commands,
4602 * you can tell which command was used by the cmd
4605 ret = match_records(hash, func, strlen(func), module);
4609 return cache_mod(tr, func_orig, module, enable);
4615 static struct ftrace_func_command ftrace_mod_cmd = {
4617 .func = ftrace_mod_callback,
4620 static int __init ftrace_mod_cmd_init(void)
4622 return register_ftrace_command(&ftrace_mod_cmd);
4624 core_initcall(ftrace_mod_cmd_init);
4626 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4627 struct ftrace_ops *op, struct ftrace_regs *fregs)
4629 struct ftrace_probe_ops *probe_ops;
4630 struct ftrace_func_probe *probe;
4632 probe = container_of(op, struct ftrace_func_probe, ops);
4633 probe_ops = probe->probe_ops;
4636 * Disable preemption for these calls to prevent a RCU grace
4637 * period. This syncs the hash iteration and freeing of items
4638 * on the hash. rcu_read_lock is too dangerous here.
4640 preempt_disable_notrace();
4641 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4642 preempt_enable_notrace();
4645 struct ftrace_func_map {
4646 struct ftrace_func_entry entry;
4650 struct ftrace_func_mapper {
4651 struct ftrace_hash hash;
4655 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4657 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4659 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4661 struct ftrace_hash *hash;
4664 * The mapper is simply a ftrace_hash, but since the entries
4665 * in the hash are not ftrace_func_entry type, we define it
4666 * as a separate structure.
4668 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4669 return (struct ftrace_func_mapper *)hash;
4673 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4674 * @mapper: The mapper that has the ip maps
4675 * @ip: the instruction pointer to find the data for
4677 * Returns the data mapped to @ip if found otherwise NULL. The return
4678 * is actually the address of the mapper data pointer. The address is
4679 * returned for use cases where the data is no bigger than a long, and
4680 * the user can use the data pointer as its data instead of having to
4681 * allocate more memory for the reference.
4683 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4686 struct ftrace_func_entry *entry;
4687 struct ftrace_func_map *map;
4689 entry = ftrace_lookup_ip(&mapper->hash, ip);
4693 map = (struct ftrace_func_map *)entry;
4698 * ftrace_func_mapper_add_ip - Map some data to an ip
4699 * @mapper: The mapper that has the ip maps
4700 * @ip: The instruction pointer address to map @data to
4701 * @data: The data to map to @ip
4703 * Returns 0 on success otherwise an error.
4705 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4706 unsigned long ip, void *data)
4708 struct ftrace_func_entry *entry;
4709 struct ftrace_func_map *map;
4711 entry = ftrace_lookup_ip(&mapper->hash, ip);
4715 map = kmalloc(sizeof(*map), GFP_KERNEL);
4722 __add_hash_entry(&mapper->hash, &map->entry);
4728 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4729 * @mapper: The mapper that has the ip maps
4730 * @ip: The instruction pointer address to remove the data from
4732 * Returns the data if it is found, otherwise NULL.
4733 * Note, if the data pointer is used as the data itself, (see
4734 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4735 * if the data pointer was set to zero.
4737 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4740 struct ftrace_func_entry *entry;
4741 struct ftrace_func_map *map;
4744 entry = ftrace_lookup_ip(&mapper->hash, ip);
4748 map = (struct ftrace_func_map *)entry;
4751 remove_hash_entry(&mapper->hash, entry);
4758 * free_ftrace_func_mapper - free a mapping of ips and data
4759 * @mapper: The mapper that has the ip maps
4760 * @free_func: A function to be called on each data item.
4762 * This is used to free the function mapper. The @free_func is optional
4763 * and can be used if the data needs to be freed as well.
4765 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4766 ftrace_mapper_func free_func)
4768 struct ftrace_func_entry *entry;
4769 struct ftrace_func_map *map;
4770 struct hlist_head *hhd;
4776 if (free_func && mapper->hash.count) {
4777 size = 1 << mapper->hash.size_bits;
4778 for (i = 0; i < size; i++) {
4779 hhd = &mapper->hash.buckets[i];
4780 hlist_for_each_entry(entry, hhd, hlist) {
4781 map = (struct ftrace_func_map *)entry;
4786 free_ftrace_hash(&mapper->hash);
4789 static void release_probe(struct ftrace_func_probe *probe)
4791 struct ftrace_probe_ops *probe_ops;
4793 mutex_lock(&ftrace_lock);
4795 WARN_ON(probe->ref <= 0);
4797 /* Subtract the ref that was used to protect this instance */
4801 probe_ops = probe->probe_ops;
4803 * Sending zero as ip tells probe_ops to free
4804 * the probe->data itself
4806 if (probe_ops->free)
4807 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4808 list_del(&probe->list);
4811 mutex_unlock(&ftrace_lock);
4814 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4817 * Add one ref to keep it from being freed when releasing the
4818 * ftrace_lock mutex.
4824 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4825 struct ftrace_probe_ops *probe_ops,
4828 struct ftrace_func_probe *probe = NULL, *iter;
4829 struct ftrace_func_entry *entry;
4830 struct ftrace_hash **orig_hash;
4831 struct ftrace_hash *old_hash;
4832 struct ftrace_hash *hash;
4841 /* We do not support '!' for function probes */
4842 if (WARN_ON(glob[0] == '!'))
4846 mutex_lock(&ftrace_lock);
4847 /* Check if the probe_ops is already registered */
4848 list_for_each_entry(iter, &tr->func_probes, list) {
4849 if (iter->probe_ops == probe_ops) {
4855 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4857 mutex_unlock(&ftrace_lock);
4860 probe->probe_ops = probe_ops;
4861 probe->ops.func = function_trace_probe_call;
4863 ftrace_ops_init(&probe->ops);
4864 list_add(&probe->list, &tr->func_probes);
4867 acquire_probe_locked(probe);
4869 mutex_unlock(&ftrace_lock);
4872 * Note, there's a small window here that the func_hash->filter_hash
4873 * may be NULL or empty. Need to be careful when reading the loop.
4875 mutex_lock(&probe->ops.func_hash->regex_lock);
4877 orig_hash = &probe->ops.func_hash->filter_hash;
4878 old_hash = *orig_hash;
4879 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4886 ret = ftrace_match_records(hash, glob, strlen(glob));
4888 /* Nothing found? */
4895 size = 1 << hash->size_bits;
4896 for (i = 0; i < size; i++) {
4897 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4898 if (ftrace_lookup_ip(old_hash, entry->ip))
4901 * The caller might want to do something special
4902 * for each function we find. We call the callback
4903 * to give the caller an opportunity to do so.
4905 if (probe_ops->init) {
4906 ret = probe_ops->init(probe_ops, tr,
4910 if (probe_ops->free && count)
4911 probe_ops->free(probe_ops, tr,
4921 mutex_lock(&ftrace_lock);
4924 /* Nothing was added? */
4929 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4934 /* One ref for each new function traced */
4935 probe->ref += count;
4937 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4938 ret = ftrace_startup(&probe->ops, 0);
4941 mutex_unlock(&ftrace_lock);
4946 mutex_unlock(&probe->ops.func_hash->regex_lock);
4947 free_ftrace_hash(hash);
4949 release_probe(probe);
4954 if (!probe_ops->free || !count)
4957 /* Failed to do the move, need to call the free functions */
4958 for (i = 0; i < size; i++) {
4959 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4960 if (ftrace_lookup_ip(old_hash, entry->ip))
4962 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4969 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4970 struct ftrace_probe_ops *probe_ops)
4972 struct ftrace_func_probe *probe = NULL, *iter;
4973 struct ftrace_ops_hash old_hash_ops;
4974 struct ftrace_func_entry *entry;
4975 struct ftrace_glob func_g;
4976 struct ftrace_hash **orig_hash;
4977 struct ftrace_hash *old_hash;
4978 struct ftrace_hash *hash = NULL;
4979 struct hlist_node *tmp;
4980 struct hlist_head hhd;
4981 char str[KSYM_SYMBOL_LEN];
4983 int i, ret = -ENODEV;
4986 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4987 func_g.search = NULL;
4991 func_g.type = filter_parse_regex(glob, strlen(glob),
4992 &func_g.search, ¬);
4993 func_g.len = strlen(func_g.search);
4995 /* we do not support '!' for function probes */
5000 mutex_lock(&ftrace_lock);
5001 /* Check if the probe_ops is already registered */
5002 list_for_each_entry(iter, &tr->func_probes, list) {
5003 if (iter->probe_ops == probe_ops) {
5009 goto err_unlock_ftrace;
5012 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
5013 goto err_unlock_ftrace;
5015 acquire_probe_locked(probe);
5017 mutex_unlock(&ftrace_lock);
5019 mutex_lock(&probe->ops.func_hash->regex_lock);
5021 orig_hash = &probe->ops.func_hash->filter_hash;
5022 old_hash = *orig_hash;
5024 if (ftrace_hash_empty(old_hash))
5027 old_hash_ops.filter_hash = old_hash;
5028 /* Probes only have filters */
5029 old_hash_ops.notrace_hash = NULL;
5032 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5036 INIT_HLIST_HEAD(&hhd);
5038 size = 1 << hash->size_bits;
5039 for (i = 0; i < size; i++) {
5040 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5042 if (func_g.search) {
5043 kallsyms_lookup(entry->ip, NULL, NULL,
5045 if (!ftrace_match(str, &func_g))
5049 remove_hash_entry(hash, entry);
5050 hlist_add_head(&entry->hlist, &hhd);
5054 /* Nothing found? */
5060 mutex_lock(&ftrace_lock);
5062 WARN_ON(probe->ref < count);
5064 probe->ref -= count;
5066 if (ftrace_hash_empty(hash))
5067 ftrace_shutdown(&probe->ops, 0);
5069 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5072 /* still need to update the function call sites */
5073 if (ftrace_enabled && !ftrace_hash_empty(hash))
5074 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5078 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5079 hlist_del(&entry->hlist);
5080 if (probe_ops->free)
5081 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5084 mutex_unlock(&ftrace_lock);
5087 mutex_unlock(&probe->ops.func_hash->regex_lock);
5088 free_ftrace_hash(hash);
5090 release_probe(probe);
5095 mutex_unlock(&ftrace_lock);
5099 void clear_ftrace_function_probes(struct trace_array *tr)
5101 struct ftrace_func_probe *probe, *n;
5103 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5104 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5107 static LIST_HEAD(ftrace_commands);
5108 static DEFINE_MUTEX(ftrace_cmd_mutex);
5111 * Currently we only register ftrace commands from __init, so mark this
5114 __init int register_ftrace_command(struct ftrace_func_command *cmd)
5116 struct ftrace_func_command *p;
5119 mutex_lock(&ftrace_cmd_mutex);
5120 list_for_each_entry(p, &ftrace_commands, list) {
5121 if (strcmp(cmd->name, p->name) == 0) {
5126 list_add(&cmd->list, &ftrace_commands);
5128 mutex_unlock(&ftrace_cmd_mutex);
5134 * Currently we only unregister ftrace commands from __init, so mark
5137 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5139 struct ftrace_func_command *p, *n;
5142 mutex_lock(&ftrace_cmd_mutex);
5143 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5144 if (strcmp(cmd->name, p->name) == 0) {
5146 list_del_init(&p->list);
5151 mutex_unlock(&ftrace_cmd_mutex);
5156 static int ftrace_process_regex(struct ftrace_iterator *iter,
5157 char *buff, int len, int enable)
5159 struct ftrace_hash *hash = iter->hash;
5160 struct trace_array *tr = iter->ops->private;
5161 char *func, *command, *next = buff;
5162 struct ftrace_func_command *p;
5165 func = strsep(&next, ":");
5168 ret = ftrace_match_records(hash, func, len);
5178 command = strsep(&next, ":");
5180 mutex_lock(&ftrace_cmd_mutex);
5181 list_for_each_entry(p, &ftrace_commands, list) {
5182 if (strcmp(p->name, command) == 0) {
5183 ret = p->func(tr, hash, func, command, next, enable);
5188 mutex_unlock(&ftrace_cmd_mutex);
5194 ftrace_regex_write(struct file *file, const char __user *ubuf,
5195 size_t cnt, loff_t *ppos, int enable)
5197 struct ftrace_iterator *iter;
5198 struct trace_parser *parser;
5204 if (file->f_mode & FMODE_READ) {
5205 struct seq_file *m = file->private_data;
5208 iter = file->private_data;
5210 if (unlikely(ftrace_disabled))
5213 /* iter->hash is a local copy, so we don't need regex_lock */
5215 parser = &iter->parser;
5216 read = trace_get_user(parser, ubuf, cnt, ppos);
5218 if (read >= 0 && trace_parser_loaded(parser) &&
5219 !trace_parser_cont(parser)) {
5220 ret = ftrace_process_regex(iter, parser->buffer,
5221 parser->idx, enable);
5222 trace_parser_clear(parser);
5233 ftrace_filter_write(struct file *file, const char __user *ubuf,
5234 size_t cnt, loff_t *ppos)
5236 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5240 ftrace_notrace_write(struct file *file, const char __user *ubuf,
5241 size_t cnt, loff_t *ppos)
5243 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5247 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5249 struct ftrace_func_entry *entry;
5251 ip = ftrace_location(ip);
5256 entry = ftrace_lookup_ip(hash, ip);
5259 free_hash_entry(hash, entry);
5263 return add_hash_entry(hash, ip);
5267 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5268 unsigned int cnt, int remove)
5273 for (i = 0; i < cnt; i++) {
5274 err = __ftrace_match_addr(hash, ips[i], remove);
5277 * This expects the @hash is a temporary hash and if this
5278 * fails the caller must free the @hash.
5287 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5288 unsigned long *ips, unsigned int cnt,
5289 int remove, int reset, int enable)
5291 struct ftrace_hash **orig_hash;
5292 struct ftrace_hash *hash;
5295 if (unlikely(ftrace_disabled))
5298 mutex_lock(&ops->func_hash->regex_lock);
5301 orig_hash = &ops->func_hash->filter_hash;
5303 orig_hash = &ops->func_hash->notrace_hash;
5306 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5308 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5312 goto out_regex_unlock;
5315 if (buf && !ftrace_match_records(hash, buf, len)) {
5317 goto out_regex_unlock;
5320 ret = ftrace_match_addr(hash, ips, cnt, remove);
5322 goto out_regex_unlock;
5325 mutex_lock(&ftrace_lock);
5326 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5327 mutex_unlock(&ftrace_lock);
5330 mutex_unlock(&ops->func_hash->regex_lock);
5332 free_ftrace_hash(hash);
5337 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5338 int remove, int reset, int enable)
5340 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5343 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5345 struct ftrace_direct_func {
5346 struct list_head next;
5351 static LIST_HEAD(ftrace_direct_funcs);
5353 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5355 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5357 static int check_direct_multi(struct ftrace_ops *ops)
5359 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5361 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5366 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5368 struct ftrace_func_entry *entry, *del;
5371 size = 1 << hash->size_bits;
5372 for (i = 0; i < size; i++) {
5373 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5374 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5375 if (del && del->direct == addr) {
5376 remove_hash_entry(direct_functions, del);
5384 * register_ftrace_direct - Call a custom trampoline directly
5385 * for multiple functions registered in @ops
5386 * @ops: The address of the struct ftrace_ops object
5387 * @addr: The address of the trampoline to call at @ops functions
5389 * This is used to connect a direct calls to @addr from the nop locations
5390 * of the functions registered in @ops (with by ftrace_set_filter_ip
5393 * The location that it calls (@addr) must be able to handle a direct call,
5394 * and save the parameters of the function being traced, and restore them
5395 * (or inject new ones if needed), before returning.
5399 * -EINVAL - The @ops object was already registered with this call or
5400 * when there are no functions in @ops object.
5401 * -EBUSY - Another direct function is already attached (there can be only one)
5402 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5403 * -ENOMEM - There was an allocation failure.
5405 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5407 struct ftrace_hash *hash, *free_hash = NULL;
5408 struct ftrace_func_entry *entry, *new;
5409 int err = -EBUSY, size, i;
5411 if (ops->func || ops->trampoline)
5413 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5415 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5418 hash = ops->func_hash->filter_hash;
5419 if (ftrace_hash_empty(hash))
5422 mutex_lock(&direct_mutex);
5424 /* Make sure requested entries are not already registered.. */
5425 size = 1 << hash->size_bits;
5426 for (i = 0; i < size; i++) {
5427 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5428 if (ftrace_find_rec_direct(entry->ip))
5433 /* ... and insert them to direct_functions hash. */
5435 for (i = 0; i < size; i++) {
5436 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5437 new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5440 entry->direct = addr;
5444 ops->func = call_direct_funcs;
5445 ops->flags = MULTI_FLAGS;
5446 ops->trampoline = FTRACE_REGS_ADDR;
5447 ops->direct_call = addr;
5449 err = register_ftrace_function_nolock(ops);
5453 remove_direct_functions_hash(hash, addr);
5456 mutex_unlock(&direct_mutex);
5459 synchronize_rcu_tasks();
5460 free_ftrace_hash(free_hash);
5464 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5467 * unregister_ftrace_direct - Remove calls to custom trampoline
5468 * previously registered by register_ftrace_direct for @ops object.
5469 * @ops: The address of the struct ftrace_ops object
5471 * This is used to remove a direct calls to @addr from the nop locations
5472 * of the functions registered in @ops (with by ftrace_set_filter_ip
5477 * -EINVAL - The @ops object was not properly registered.
5479 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5482 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5485 if (check_direct_multi(ops))
5487 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5490 mutex_lock(&direct_mutex);
5491 err = unregister_ftrace_function(ops);
5492 remove_direct_functions_hash(hash, addr);
5493 mutex_unlock(&direct_mutex);
5495 /* cleanup for possible another register call */
5497 ops->trampoline = 0;
5500 ftrace_free_filter(ops);
5503 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5506 __modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5508 struct ftrace_hash *hash;
5509 struct ftrace_func_entry *entry, *iter;
5510 static struct ftrace_ops tmp_ops = {
5511 .func = ftrace_stub,
5512 .flags = FTRACE_OPS_FL_STUB,
5517 lockdep_assert_held_once(&direct_mutex);
5519 /* Enable the tmp_ops to have the same functions as the direct ops */
5520 ftrace_ops_init(&tmp_ops);
5521 tmp_ops.func_hash = ops->func_hash;
5522 tmp_ops.direct_call = addr;
5524 err = register_ftrace_function_nolock(&tmp_ops);
5529 * Now the ftrace_ops_list_func() is called to do the direct callers.
5530 * We can safely change the direct functions attached to each entry.
5532 mutex_lock(&ftrace_lock);
5534 hash = ops->func_hash->filter_hash;
5535 size = 1 << hash->size_bits;
5536 for (i = 0; i < size; i++) {
5537 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5538 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5541 entry->direct = addr;
5544 /* Prevent store tearing if a trampoline concurrently accesses the value */
5545 WRITE_ONCE(ops->direct_call, addr);
5547 mutex_unlock(&ftrace_lock);
5549 /* Removing the tmp_ops will add the updated direct callers to the functions */
5550 unregister_ftrace_function(&tmp_ops);
5556 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5557 * to call something else
5558 * @ops: The address of the struct ftrace_ops object
5559 * @addr: The address of the new trampoline to call at @ops functions
5561 * This is used to unregister currently registered direct caller and
5562 * register new one @addr on functions registered in @ops object.
5564 * Note there's window between ftrace_shutdown and ftrace_startup calls
5565 * where there will be no callbacks called.
5567 * Caller should already have direct_mutex locked, so we don't lock
5568 * direct_mutex here.
5570 * Returns: zero on success. Non zero on error, which includes:
5571 * -EINVAL - The @ops object was not properly registered.
5573 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5575 if (check_direct_multi(ops))
5577 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5580 return __modify_ftrace_direct(ops, addr);
5582 EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5585 * modify_ftrace_direct - Modify an existing direct 'multi' call
5586 * to call something else
5587 * @ops: The address of the struct ftrace_ops object
5588 * @addr: The address of the new trampoline to call at @ops functions
5590 * This is used to unregister currently registered direct caller and
5591 * register new one @addr on functions registered in @ops object.
5593 * Note there's window between ftrace_shutdown and ftrace_startup calls
5594 * where there will be no callbacks called.
5596 * Returns: zero on success. Non zero on error, which includes:
5597 * -EINVAL - The @ops object was not properly registered.
5599 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5603 if (check_direct_multi(ops))
5605 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5608 mutex_lock(&direct_mutex);
5609 err = __modify_ftrace_direct(ops, addr);
5610 mutex_unlock(&direct_mutex);
5613 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5614 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5617 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5618 * @ops - the ops to set the filter with
5619 * @ip - the address to add to or remove from the filter.
5620 * @remove - non zero to remove the ip from the filter
5621 * @reset - non zero to reset all filters before applying this filter.
5623 * Filters denote which functions should be enabled when tracing is enabled
5624 * If @ip is NULL, it fails to update filter.
5626 * This can allocate memory which must be freed before @ops can be freed,
5627 * either by removing each filtered addr or by using
5628 * ftrace_free_filter(@ops).
5630 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5631 int remove, int reset)
5633 ftrace_ops_init(ops);
5634 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5636 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5639 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5640 * @ops - the ops to set the filter with
5641 * @ips - the array of addresses to add to or remove from the filter.
5642 * @cnt - the number of addresses in @ips
5643 * @remove - non zero to remove ips from the filter
5644 * @reset - non zero to reset all filters before applying this filter.
5646 * Filters denote which functions should be enabled when tracing is enabled
5647 * If @ips array or any ip specified within is NULL , it fails to update filter.
5649 * This can allocate memory which must be freed before @ops can be freed,
5650 * either by removing each filtered addr or by using
5651 * ftrace_free_filter(@ops).
5653 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5654 unsigned int cnt, int remove, int reset)
5656 ftrace_ops_init(ops);
5657 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5659 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5662 * ftrace_ops_set_global_filter - setup ops to use global filters
5663 * @ops - the ops which will use the global filters
5665 * ftrace users who need global function trace filtering should call this.
5666 * It can set the global filter only if ops were not initialized before.
5668 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5670 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5673 ftrace_ops_init(ops);
5674 ops->func_hash = &global_ops.local_hash;
5676 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5679 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5680 int reset, int enable)
5682 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5686 * ftrace_set_filter - set a function to filter on in ftrace
5687 * @ops - the ops to set the filter with
5688 * @buf - the string that holds the function filter text.
5689 * @len - the length of the string.
5690 * @reset - non zero to reset all filters before applying this filter.
5692 * Filters denote which functions should be enabled when tracing is enabled.
5693 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5695 * This can allocate memory which must be freed before @ops can be freed,
5696 * either by removing each filtered addr or by using
5697 * ftrace_free_filter(@ops).
5699 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5702 ftrace_ops_init(ops);
5703 return ftrace_set_regex(ops, buf, len, reset, 1);
5705 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5708 * ftrace_set_notrace - set a function to not trace in ftrace
5709 * @ops - the ops to set the notrace filter with
5710 * @buf - the string that holds the function notrace text.
5711 * @len - the length of the string.
5712 * @reset - non zero to reset all filters before applying this filter.
5714 * Notrace Filters denote which functions should not be enabled when tracing
5715 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5718 * This can allocate memory which must be freed before @ops can be freed,
5719 * either by removing each filtered addr or by using
5720 * ftrace_free_filter(@ops).
5722 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5725 ftrace_ops_init(ops);
5726 return ftrace_set_regex(ops, buf, len, reset, 0);
5728 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5730 * ftrace_set_global_filter - set a function to filter on with global tracers
5731 * @buf - the string that holds the function filter text.
5732 * @len - the length of the string.
5733 * @reset - non zero to reset all filters before applying this filter.
5735 * Filters denote which functions should be enabled when tracing is enabled.
5736 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5738 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5740 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5742 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5745 * ftrace_set_global_notrace - set a function to not trace with global tracers
5746 * @buf - the string that holds the function notrace text.
5747 * @len - the length of the string.
5748 * @reset - non zero to reset all filters before applying this filter.
5750 * Notrace Filters denote which functions should not be enabled when tracing
5751 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5754 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5756 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5758 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5761 * command line interface to allow users to set filters on boot up.
5763 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5764 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5765 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5767 /* Used by function selftest to not test if filter is set */
5768 bool ftrace_filter_param __initdata;
5770 static int __init set_ftrace_notrace(char *str)
5772 ftrace_filter_param = true;
5773 strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5776 __setup("ftrace_notrace=", set_ftrace_notrace);
5778 static int __init set_ftrace_filter(char *str)
5780 ftrace_filter_param = true;
5781 strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5784 __setup("ftrace_filter=", set_ftrace_filter);
5786 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5787 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5788 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5789 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5791 static int __init set_graph_function(char *str)
5793 strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5796 __setup("ftrace_graph_filter=", set_graph_function);
5798 static int __init set_graph_notrace_function(char *str)
5800 strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5803 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5805 static int __init set_graph_max_depth_function(char *str)
5809 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5812 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5814 static void __init set_ftrace_early_graph(char *buf, int enable)
5818 struct ftrace_hash *hash;
5820 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5821 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5825 func = strsep(&buf, ",");
5826 /* we allow only one expression at a time */
5827 ret = ftrace_graph_set_hash(hash, func);
5829 printk(KERN_DEBUG "ftrace: function %s not "
5830 "traceable\n", func);
5834 ftrace_graph_hash = hash;
5836 ftrace_graph_notrace_hash = hash;
5838 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5841 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5845 ftrace_ops_init(ops);
5848 func = strsep(&buf, ",");
5849 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5853 static void __init set_ftrace_early_filters(void)
5855 if (ftrace_filter_buf[0])
5856 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5857 if (ftrace_notrace_buf[0])
5858 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5859 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5860 if (ftrace_graph_buf[0])
5861 set_ftrace_early_graph(ftrace_graph_buf, 1);
5862 if (ftrace_graph_notrace_buf[0])
5863 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5864 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5867 int ftrace_regex_release(struct inode *inode, struct file *file)
5869 struct seq_file *m = (struct seq_file *)file->private_data;
5870 struct ftrace_iterator *iter;
5871 struct ftrace_hash **orig_hash;
5872 struct trace_parser *parser;
5875 if (file->f_mode & FMODE_READ) {
5877 seq_release(inode, file);
5879 iter = file->private_data;
5881 parser = &iter->parser;
5882 if (trace_parser_loaded(parser)) {
5883 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5885 ftrace_process_regex(iter, parser->buffer,
5886 parser->idx, enable);
5889 trace_parser_put(parser);
5891 mutex_lock(&iter->ops->func_hash->regex_lock);
5893 if (file->f_mode & FMODE_WRITE) {
5894 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5897 orig_hash = &iter->ops->func_hash->filter_hash;
5899 if (list_empty(&iter->tr->mod_trace))
5900 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5902 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5905 orig_hash = &iter->ops->func_hash->notrace_hash;
5907 mutex_lock(&ftrace_lock);
5908 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5909 iter->hash, filter_hash);
5910 mutex_unlock(&ftrace_lock);
5912 /* For read only, the hash is the ops hash */
5916 mutex_unlock(&iter->ops->func_hash->regex_lock);
5917 free_ftrace_hash(iter->hash);
5919 trace_array_put(iter->tr);
5925 static const struct file_operations ftrace_avail_fops = {
5926 .open = ftrace_avail_open,
5928 .llseek = seq_lseek,
5929 .release = seq_release_private,
5932 static const struct file_operations ftrace_enabled_fops = {
5933 .open = ftrace_enabled_open,
5935 .llseek = seq_lseek,
5936 .release = seq_release_private,
5939 static const struct file_operations ftrace_touched_fops = {
5940 .open = ftrace_touched_open,
5942 .llseek = seq_lseek,
5943 .release = seq_release_private,
5946 static const struct file_operations ftrace_avail_addrs_fops = {
5947 .open = ftrace_avail_addrs_open,
5949 .llseek = seq_lseek,
5950 .release = seq_release_private,
5953 static const struct file_operations ftrace_filter_fops = {
5954 .open = ftrace_filter_open,
5956 .write = ftrace_filter_write,
5957 .llseek = tracing_lseek,
5958 .release = ftrace_regex_release,
5961 static const struct file_operations ftrace_notrace_fops = {
5962 .open = ftrace_notrace_open,
5964 .write = ftrace_notrace_write,
5965 .llseek = tracing_lseek,
5966 .release = ftrace_regex_release,
5969 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5971 static DEFINE_MUTEX(graph_lock);
5973 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5974 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5976 enum graph_filter_type {
5977 GRAPH_FILTER_NOTRACE = 0,
5978 GRAPH_FILTER_FUNCTION,
5981 #define FTRACE_GRAPH_EMPTY ((void *)1)
5983 struct ftrace_graph_data {
5984 struct ftrace_hash *hash;
5985 struct ftrace_func_entry *entry;
5986 int idx; /* for hash table iteration */
5987 enum graph_filter_type type;
5988 struct ftrace_hash *new_hash;
5989 const struct seq_operations *seq_ops;
5990 struct trace_parser parser;
5994 __g_next(struct seq_file *m, loff_t *pos)
5996 struct ftrace_graph_data *fgd = m->private;
5997 struct ftrace_func_entry *entry = fgd->entry;
5998 struct hlist_head *head;
5999 int i, idx = fgd->idx;
6001 if (*pos >= fgd->hash->count)
6005 hlist_for_each_entry_continue(entry, hlist) {
6013 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6014 head = &fgd->hash->buckets[i];
6015 hlist_for_each_entry(entry, head, hlist) {
6025 g_next(struct seq_file *m, void *v, loff_t *pos)
6028 return __g_next(m, pos);
6031 static void *g_start(struct seq_file *m, loff_t *pos)
6033 struct ftrace_graph_data *fgd = m->private;
6035 mutex_lock(&graph_lock);
6037 if (fgd->type == GRAPH_FILTER_FUNCTION)
6038 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6039 lockdep_is_held(&graph_lock));
6041 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6042 lockdep_is_held(&graph_lock));
6044 /* Nothing, tell g_show to print all functions are enabled */
6045 if (ftrace_hash_empty(fgd->hash) && !*pos)
6046 return FTRACE_GRAPH_EMPTY;
6050 return __g_next(m, pos);
6053 static void g_stop(struct seq_file *m, void *p)
6055 mutex_unlock(&graph_lock);
6058 static int g_show(struct seq_file *m, void *v)
6060 struct ftrace_func_entry *entry = v;
6065 if (entry == FTRACE_GRAPH_EMPTY) {
6066 struct ftrace_graph_data *fgd = m->private;
6068 if (fgd->type == GRAPH_FILTER_FUNCTION)
6069 seq_puts(m, "#### all functions enabled ####\n");
6071 seq_puts(m, "#### no functions disabled ####\n");
6075 seq_printf(m, "%ps\n", (void *)entry->ip);
6080 static const struct seq_operations ftrace_graph_seq_ops = {
6088 __ftrace_graph_open(struct inode *inode, struct file *file,
6089 struct ftrace_graph_data *fgd)
6092 struct ftrace_hash *new_hash = NULL;
6094 ret = security_locked_down(LOCKDOWN_TRACEFS);
6098 if (file->f_mode & FMODE_WRITE) {
6099 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6101 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6104 if (file->f_flags & O_TRUNC)
6105 new_hash = alloc_ftrace_hash(size_bits);
6107 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6115 if (file->f_mode & FMODE_READ) {
6116 ret = seq_open(file, &ftrace_graph_seq_ops);
6118 struct seq_file *m = file->private_data;
6122 free_ftrace_hash(new_hash);
6126 file->private_data = fgd;
6129 if (ret < 0 && file->f_mode & FMODE_WRITE)
6130 trace_parser_put(&fgd->parser);
6132 fgd->new_hash = new_hash;
6135 * All uses of fgd->hash must be taken with the graph_lock
6136 * held. The graph_lock is going to be released, so force
6137 * fgd->hash to be reinitialized when it is taken again.
6145 ftrace_graph_open(struct inode *inode, struct file *file)
6147 struct ftrace_graph_data *fgd;
6150 if (unlikely(ftrace_disabled))
6153 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6157 mutex_lock(&graph_lock);
6159 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6160 lockdep_is_held(&graph_lock));
6161 fgd->type = GRAPH_FILTER_FUNCTION;
6162 fgd->seq_ops = &ftrace_graph_seq_ops;
6164 ret = __ftrace_graph_open(inode, file, fgd);
6168 mutex_unlock(&graph_lock);
6173 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6175 struct ftrace_graph_data *fgd;
6178 if (unlikely(ftrace_disabled))
6181 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6185 mutex_lock(&graph_lock);
6187 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6188 lockdep_is_held(&graph_lock));
6189 fgd->type = GRAPH_FILTER_NOTRACE;
6190 fgd->seq_ops = &ftrace_graph_seq_ops;
6192 ret = __ftrace_graph_open(inode, file, fgd);
6196 mutex_unlock(&graph_lock);
6201 ftrace_graph_release(struct inode *inode, struct file *file)
6203 struct ftrace_graph_data *fgd;
6204 struct ftrace_hash *old_hash, *new_hash;
6205 struct trace_parser *parser;
6208 if (file->f_mode & FMODE_READ) {
6209 struct seq_file *m = file->private_data;
6212 seq_release(inode, file);
6214 fgd = file->private_data;
6218 if (file->f_mode & FMODE_WRITE) {
6220 parser = &fgd->parser;
6222 if (trace_parser_loaded((parser))) {
6223 ret = ftrace_graph_set_hash(fgd->new_hash,
6227 trace_parser_put(parser);
6229 new_hash = __ftrace_hash_move(fgd->new_hash);
6235 mutex_lock(&graph_lock);
6237 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6238 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6239 lockdep_is_held(&graph_lock));
6240 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6242 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6243 lockdep_is_held(&graph_lock));
6244 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6247 mutex_unlock(&graph_lock);
6250 * We need to do a hard force of sched synchronization.
6251 * This is because we use preempt_disable() to do RCU, but
6252 * the function tracers can be called where RCU is not watching
6253 * (like before user_exit()). We can not rely on the RCU
6254 * infrastructure to do the synchronization, thus we must do it
6257 if (old_hash != EMPTY_HASH)
6258 synchronize_rcu_tasks_rude();
6260 free_ftrace_hash(old_hash);
6264 free_ftrace_hash(fgd->new_hash);
6271 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6273 struct ftrace_glob func_g;
6274 struct dyn_ftrace *rec;
6275 struct ftrace_page *pg;
6276 struct ftrace_func_entry *entry;
6281 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6282 &func_g.search, ¬);
6284 func_g.len = strlen(func_g.search);
6286 mutex_lock(&ftrace_lock);
6288 if (unlikely(ftrace_disabled)) {
6289 mutex_unlock(&ftrace_lock);
6293 do_for_each_ftrace_rec(pg, rec) {
6295 if (rec->flags & FTRACE_FL_DISABLED)
6298 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6299 entry = ftrace_lookup_ip(hash, rec->ip);
6306 if (add_hash_entry(hash, rec->ip) < 0)
6310 free_hash_entry(hash, entry);
6315 } while_for_each_ftrace_rec();
6317 mutex_unlock(&ftrace_lock);
6326 ftrace_graph_write(struct file *file, const char __user *ubuf,
6327 size_t cnt, loff_t *ppos)
6329 ssize_t read, ret = 0;
6330 struct ftrace_graph_data *fgd = file->private_data;
6331 struct trace_parser *parser;
6336 /* Read mode uses seq functions */
6337 if (file->f_mode & FMODE_READ) {
6338 struct seq_file *m = file->private_data;
6342 parser = &fgd->parser;
6344 read = trace_get_user(parser, ubuf, cnt, ppos);
6346 if (read >= 0 && trace_parser_loaded(parser) &&
6347 !trace_parser_cont(parser)) {
6349 ret = ftrace_graph_set_hash(fgd->new_hash,
6351 trace_parser_clear(parser);
6360 static const struct file_operations ftrace_graph_fops = {
6361 .open = ftrace_graph_open,
6363 .write = ftrace_graph_write,
6364 .llseek = tracing_lseek,
6365 .release = ftrace_graph_release,
6368 static const struct file_operations ftrace_graph_notrace_fops = {
6369 .open = ftrace_graph_notrace_open,
6371 .write = ftrace_graph_write,
6372 .llseek = tracing_lseek,
6373 .release = ftrace_graph_release,
6375 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6377 void ftrace_create_filter_files(struct ftrace_ops *ops,
6378 struct dentry *parent)
6381 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6382 ops, &ftrace_filter_fops);
6384 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6385 ops, &ftrace_notrace_fops);
6389 * The name "destroy_filter_files" is really a misnomer. Although
6390 * in the future, it may actually delete the files, but this is
6391 * really intended to make sure the ops passed in are disabled
6392 * and that when this function returns, the caller is free to
6395 * The "destroy" name is only to match the "create" name that this
6396 * should be paired with.
6398 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6400 mutex_lock(&ftrace_lock);
6401 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6402 ftrace_shutdown(ops, 0);
6403 ops->flags |= FTRACE_OPS_FL_DELETED;
6404 ftrace_free_filter(ops);
6405 mutex_unlock(&ftrace_lock);
6408 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6411 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6412 d_tracer, NULL, &ftrace_avail_fops);
6414 trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6415 d_tracer, NULL, &ftrace_avail_addrs_fops);
6417 trace_create_file("enabled_functions", TRACE_MODE_READ,
6418 d_tracer, NULL, &ftrace_enabled_fops);
6420 trace_create_file("touched_functions", TRACE_MODE_READ,
6421 d_tracer, NULL, &ftrace_touched_fops);
6423 ftrace_create_filter_files(&global_ops, d_tracer);
6425 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6426 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6428 &ftrace_graph_fops);
6429 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6431 &ftrace_graph_notrace_fops);
6432 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6437 static int ftrace_cmp_ips(const void *a, const void *b)
6439 const unsigned long *ipa = a;
6440 const unsigned long *ipb = b;
6449 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6450 static void test_is_sorted(unsigned long *start, unsigned long count)
6454 for (i = 1; i < count; i++) {
6455 if (WARN(start[i - 1] > start[i],
6456 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6457 (void *)start[i - 1], start[i - 1],
6458 (void *)start[i], start[i]))
6462 pr_info("ftrace section at %px sorted properly\n", start);
6465 static void test_is_sorted(unsigned long *start, unsigned long count)
6470 static int ftrace_process_locs(struct module *mod,
6471 unsigned long *start,
6474 struct ftrace_page *start_pg;
6475 struct ftrace_page *pg;
6476 struct dyn_ftrace *rec;
6477 unsigned long count;
6480 unsigned long flags = 0; /* Shut up gcc */
6483 count = end - start;
6489 * Sorting mcount in vmlinux at build time depend on
6490 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6491 * modules can not be sorted at build time.
6493 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6494 sort(start, count, sizeof(*start),
6495 ftrace_cmp_ips, NULL);
6497 test_is_sorted(start, count);
6500 start_pg = ftrace_allocate_pages(count);
6504 mutex_lock(&ftrace_lock);
6507 * Core and each module needs their own pages, as
6508 * modules will free them when they are removed.
6509 * Force a new page to be allocated for modules.
6512 WARN_ON(ftrace_pages || ftrace_pages_start);
6513 /* First initialization */
6514 ftrace_pages = ftrace_pages_start = start_pg;
6519 if (WARN_ON(ftrace_pages->next)) {
6520 /* Hmm, we have free pages? */
6521 while (ftrace_pages->next)
6522 ftrace_pages = ftrace_pages->next;
6525 ftrace_pages->next = start_pg;
6531 unsigned long end_offset;
6532 addr = ftrace_call_adjust(*p++);
6534 * Some architecture linkers will pad between
6535 * the different mcount_loc sections of different
6536 * object files to satisfy alignments.
6537 * Skip any NULL pointers.
6542 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6543 if (end_offset > PAGE_SIZE << pg->order) {
6544 /* We should have allocated enough */
6545 if (WARN_ON(!pg->next))
6550 rec = &pg->records[pg->index++];
6554 /* We should have used all pages */
6557 /* Assign the last page to ftrace_pages */
6561 * We only need to disable interrupts on start up
6562 * because we are modifying code that an interrupt
6563 * may execute, and the modification is not atomic.
6564 * But for modules, nothing runs the code we modify
6565 * until we are finished with it, and there's no
6566 * reason to cause large interrupt latencies while we do it.
6569 local_irq_save(flags);
6570 ftrace_update_code(mod, start_pg);
6572 local_irq_restore(flags);
6575 mutex_unlock(&ftrace_lock);
6580 struct ftrace_mod_func {
6581 struct list_head list;
6587 struct ftrace_mod_map {
6588 struct rcu_head rcu;
6589 struct list_head list;
6591 unsigned long start_addr;
6592 unsigned long end_addr;
6593 struct list_head funcs;
6594 unsigned int num_funcs;
6597 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6598 unsigned long *value, char *type,
6599 char *name, char *module_name,
6602 struct ftrace_ops *op;
6604 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6605 if (!op->trampoline || symnum--)
6607 *value = op->trampoline;
6609 strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6610 strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6618 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6620 * Check if the current ops references the given ip.
6622 * If the ops traces all functions, then it was already accounted for.
6623 * If the ops does not trace the current record function, skip it.
6624 * If the ops ignores the function via notrace filter, skip it.
6627 ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6629 /* If ops isn't enabled, ignore it */
6630 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6633 /* If ops traces all then it includes this function */
6634 if (ops_traces_mod(ops))
6637 /* The function must be in the filter */
6638 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6639 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6642 /* If in notrace hash, we ignore it too */
6643 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6650 #ifdef CONFIG_MODULES
6652 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6654 static LIST_HEAD(ftrace_mod_maps);
6656 static int referenced_filters(struct dyn_ftrace *rec)
6658 struct ftrace_ops *ops;
6661 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6662 if (ops_references_ip(ops, rec->ip)) {
6663 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6665 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6668 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6669 rec->flags |= FTRACE_FL_REGS;
6670 if (cnt == 1 && ops->trampoline)
6671 rec->flags |= FTRACE_FL_TRAMP;
6673 rec->flags &= ~FTRACE_FL_TRAMP;
6681 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6683 struct ftrace_func_entry *entry;
6684 struct dyn_ftrace *rec;
6687 if (ftrace_hash_empty(hash))
6690 for (i = 0; i < pg->index; i++) {
6691 rec = &pg->records[i];
6692 entry = __ftrace_lookup_ip(hash, rec->ip);
6694 * Do not allow this rec to match again.
6695 * Yeah, it may waste some memory, but will be removed
6696 * if/when the hash is modified again.
6703 /* Clear any records from hashes */
6704 static void clear_mod_from_hashes(struct ftrace_page *pg)
6706 struct trace_array *tr;
6708 mutex_lock(&trace_types_lock);
6709 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6710 if (!tr->ops || !tr->ops->func_hash)
6712 mutex_lock(&tr->ops->func_hash->regex_lock);
6713 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6714 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6715 mutex_unlock(&tr->ops->func_hash->regex_lock);
6717 mutex_unlock(&trace_types_lock);
6720 static void ftrace_free_mod_map(struct rcu_head *rcu)
6722 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6723 struct ftrace_mod_func *mod_func;
6724 struct ftrace_mod_func *n;
6726 /* All the contents of mod_map are now not visible to readers */
6727 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6728 kfree(mod_func->name);
6729 list_del(&mod_func->list);
6736 void ftrace_release_mod(struct module *mod)
6738 struct ftrace_mod_map *mod_map;
6739 struct ftrace_mod_map *n;
6740 struct dyn_ftrace *rec;
6741 struct ftrace_page **last_pg;
6742 struct ftrace_page *tmp_page = NULL;
6743 struct ftrace_page *pg;
6745 mutex_lock(&ftrace_lock);
6747 if (ftrace_disabled)
6750 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6751 if (mod_map->mod == mod) {
6752 list_del_rcu(&mod_map->list);
6753 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6759 * Each module has its own ftrace_pages, remove
6760 * them from the list.
6762 last_pg = &ftrace_pages_start;
6763 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6764 rec = &pg->records[0];
6765 if (within_module_core(rec->ip, mod) ||
6766 within_module_init(rec->ip, mod)) {
6768 * As core pages are first, the first
6769 * page should never be a module page.
6771 if (WARN_ON(pg == ftrace_pages_start))
6774 /* Check if we are deleting the last page */
6775 if (pg == ftrace_pages)
6776 ftrace_pages = next_to_ftrace_page(last_pg);
6778 ftrace_update_tot_cnt -= pg->index;
6779 *last_pg = pg->next;
6781 pg->next = tmp_page;
6784 last_pg = &pg->next;
6787 mutex_unlock(&ftrace_lock);
6789 for (pg = tmp_page; pg; pg = tmp_page) {
6791 /* Needs to be called outside of ftrace_lock */
6792 clear_mod_from_hashes(pg);
6795 free_pages((unsigned long)pg->records, pg->order);
6796 ftrace_number_of_pages -= 1 << pg->order;
6798 tmp_page = pg->next;
6800 ftrace_number_of_groups--;
6804 void ftrace_module_enable(struct module *mod)
6806 struct dyn_ftrace *rec;
6807 struct ftrace_page *pg;
6809 mutex_lock(&ftrace_lock);
6811 if (ftrace_disabled)
6815 * If the tracing is enabled, go ahead and enable the record.
6817 * The reason not to enable the record immediately is the
6818 * inherent check of ftrace_make_nop/ftrace_make_call for
6819 * correct previous instructions. Making first the NOP
6820 * conversion puts the module to the correct state, thus
6821 * passing the ftrace_make_call check.
6823 * We also delay this to after the module code already set the
6824 * text to read-only, as we now need to set it back to read-write
6825 * so that we can modify the text.
6827 if (ftrace_start_up)
6828 ftrace_arch_code_modify_prepare();
6830 do_for_each_ftrace_rec(pg, rec) {
6833 * do_for_each_ftrace_rec() is a double loop.
6834 * module text shares the pg. If a record is
6835 * not part of this module, then skip this pg,
6836 * which the "break" will do.
6838 if (!within_module_core(rec->ip, mod) &&
6839 !within_module_init(rec->ip, mod))
6842 /* Weak functions should still be ignored */
6843 if (!test_for_valid_rec(rec)) {
6844 /* Clear all other flags. Should not be enabled anyway */
6845 rec->flags = FTRACE_FL_DISABLED;
6852 * When adding a module, we need to check if tracers are
6853 * currently enabled and if they are, and can trace this record,
6854 * we need to enable the module functions as well as update the
6855 * reference counts for those function records.
6857 if (ftrace_start_up)
6858 cnt += referenced_filters(rec);
6860 rec->flags &= ~FTRACE_FL_DISABLED;
6863 if (ftrace_start_up && cnt) {
6864 int failed = __ftrace_replace_code(rec, 1);
6866 ftrace_bug(failed, rec);
6871 } while_for_each_ftrace_rec();
6874 if (ftrace_start_up)
6875 ftrace_arch_code_modify_post_process();
6878 mutex_unlock(&ftrace_lock);
6880 process_cached_mods(mod->name);
6883 void ftrace_module_init(struct module *mod)
6887 if (ftrace_disabled || !mod->num_ftrace_callsites)
6890 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6891 mod->ftrace_callsites + mod->num_ftrace_callsites);
6893 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6897 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6898 struct dyn_ftrace *rec)
6900 struct ftrace_mod_func *mod_func;
6901 unsigned long symsize;
6902 unsigned long offset;
6903 char str[KSYM_SYMBOL_LEN];
6907 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6911 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6915 mod_func->name = kstrdup(str, GFP_KERNEL);
6916 if (!mod_func->name) {
6921 mod_func->ip = rec->ip - offset;
6922 mod_func->size = symsize;
6924 mod_map->num_funcs++;
6926 list_add_rcu(&mod_func->list, &mod_map->funcs);
6929 static struct ftrace_mod_map *
6930 allocate_ftrace_mod_map(struct module *mod,
6931 unsigned long start, unsigned long end)
6933 struct ftrace_mod_map *mod_map;
6935 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6940 mod_map->start_addr = start;
6941 mod_map->end_addr = end;
6942 mod_map->num_funcs = 0;
6944 INIT_LIST_HEAD_RCU(&mod_map->funcs);
6946 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6952 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6953 unsigned long addr, unsigned long *size,
6954 unsigned long *off, char *sym)
6956 struct ftrace_mod_func *found_func = NULL;
6957 struct ftrace_mod_func *mod_func;
6959 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6960 if (addr >= mod_func->ip &&
6961 addr < mod_func->ip + mod_func->size) {
6962 found_func = mod_func;
6969 *size = found_func->size;
6971 *off = addr - found_func->ip;
6973 strscpy(sym, found_func->name, KSYM_NAME_LEN);
6975 return found_func->name;
6982 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
6983 unsigned long *off, char **modname, char *sym)
6985 struct ftrace_mod_map *mod_map;
6986 const char *ret = NULL;
6988 /* mod_map is freed via call_rcu() */
6990 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6991 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6994 *modname = mod_map->mod->name;
7003 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7004 char *type, char *name,
7005 char *module_name, int *exported)
7007 struct ftrace_mod_map *mod_map;
7008 struct ftrace_mod_func *mod_func;
7012 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7014 if (symnum >= mod_map->num_funcs) {
7015 symnum -= mod_map->num_funcs;
7019 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7025 *value = mod_func->ip;
7027 strscpy(name, mod_func->name, KSYM_NAME_LEN);
7028 strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7036 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7037 module_name, exported);
7043 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7044 struct dyn_ftrace *rec) { }
7045 static inline struct ftrace_mod_map *
7046 allocate_ftrace_mod_map(struct module *mod,
7047 unsigned long start, unsigned long end)
7051 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7052 char *type, char *name, char *module_name,
7058 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7059 module_name, exported);
7063 #endif /* CONFIG_MODULES */
7065 struct ftrace_init_func {
7066 struct list_head list;
7070 /* Clear any init ips from hashes */
7072 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7074 struct ftrace_func_entry *entry;
7076 entry = ftrace_lookup_ip(hash, func->ip);
7078 * Do not allow this rec to match again.
7079 * Yeah, it may waste some memory, but will be removed
7080 * if/when the hash is modified again.
7087 clear_func_from_hashes(struct ftrace_init_func *func)
7089 struct trace_array *tr;
7091 mutex_lock(&trace_types_lock);
7092 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7093 if (!tr->ops || !tr->ops->func_hash)
7095 mutex_lock(&tr->ops->func_hash->regex_lock);
7096 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7097 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7098 mutex_unlock(&tr->ops->func_hash->regex_lock);
7100 mutex_unlock(&trace_types_lock);
7103 static void add_to_clear_hash_list(struct list_head *clear_list,
7104 struct dyn_ftrace *rec)
7106 struct ftrace_init_func *func;
7108 func = kmalloc(sizeof(*func), GFP_KERNEL);
7110 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7115 list_add(&func->list, clear_list);
7118 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7120 unsigned long start = (unsigned long)(start_ptr);
7121 unsigned long end = (unsigned long)(end_ptr);
7122 struct ftrace_page **last_pg = &ftrace_pages_start;
7123 struct ftrace_page *pg;
7124 struct dyn_ftrace *rec;
7125 struct dyn_ftrace key;
7126 struct ftrace_mod_map *mod_map = NULL;
7127 struct ftrace_init_func *func, *func_next;
7128 struct list_head clear_hash;
7130 INIT_LIST_HEAD(&clear_hash);
7133 key.flags = end; /* overload flags, as it is unsigned long */
7135 mutex_lock(&ftrace_lock);
7138 * If we are freeing module init memory, then check if
7139 * any tracer is active. If so, we need to save a mapping of
7140 * the module functions being freed with the address.
7142 if (mod && ftrace_ops_list != &ftrace_list_end)
7143 mod_map = allocate_ftrace_mod_map(mod, start, end);
7145 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7146 if (end < pg->records[0].ip ||
7147 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7150 rec = bsearch(&key, pg->records, pg->index,
7151 sizeof(struct dyn_ftrace),
7156 /* rec will be cleared from hashes after ftrace_lock unlock */
7157 add_to_clear_hash_list(&clear_hash, rec);
7160 save_ftrace_mod_rec(mod_map, rec);
7163 ftrace_update_tot_cnt--;
7165 *last_pg = pg->next;
7167 free_pages((unsigned long)pg->records, pg->order);
7168 ftrace_number_of_pages -= 1 << pg->order;
7170 ftrace_number_of_groups--;
7172 pg = container_of(last_pg, struct ftrace_page, next);
7177 memmove(rec, rec + 1,
7178 (pg->index - (rec - pg->records)) * sizeof(*rec));
7179 /* More than one function may be in this block */
7182 mutex_unlock(&ftrace_lock);
7184 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7185 clear_func_from_hashes(func);
7190 void __init ftrace_free_init_mem(void)
7192 void *start = (void *)(&__init_begin);
7193 void *end = (void *)(&__init_end);
7195 ftrace_boot_snapshot();
7197 ftrace_free_mem(NULL, start, end);
7200 int __init __weak ftrace_dyn_arch_init(void)
7205 void __init ftrace_init(void)
7207 extern unsigned long __start_mcount_loc[];
7208 extern unsigned long __stop_mcount_loc[];
7209 unsigned long count, flags;
7212 local_irq_save(flags);
7213 ret = ftrace_dyn_arch_init();
7214 local_irq_restore(flags);
7218 count = __stop_mcount_loc - __start_mcount_loc;
7220 pr_info("ftrace: No functions to be traced?\n");
7224 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7225 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7227 ret = ftrace_process_locs(NULL,
7231 pr_warn("ftrace: failed to allocate entries for functions\n");
7235 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7236 ftrace_number_of_pages, ftrace_number_of_groups);
7238 last_ftrace_enabled = ftrace_enabled = 1;
7240 set_ftrace_early_filters();
7244 ftrace_disabled = 1;
7247 /* Do nothing if arch does not support this */
7248 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7252 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7254 unsigned long trampoline = ops->trampoline;
7256 arch_ftrace_update_trampoline(ops);
7257 if (ops->trampoline && ops->trampoline != trampoline &&
7258 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7259 /* Add to kallsyms before the perf events */
7260 ftrace_add_trampoline_to_kallsyms(ops);
7261 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7262 ops->trampoline, ops->trampoline_size, false,
7263 FTRACE_TRAMPOLINE_SYM);
7265 * Record the perf text poke event after the ksymbol register
7268 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7269 (void *)ops->trampoline,
7270 ops->trampoline_size);
7274 void ftrace_init_trace_array(struct trace_array *tr)
7276 INIT_LIST_HEAD(&tr->func_probes);
7277 INIT_LIST_HEAD(&tr->mod_trace);
7278 INIT_LIST_HEAD(&tr->mod_notrace);
7282 struct ftrace_ops global_ops = {
7283 .func = ftrace_stub,
7284 .flags = FTRACE_OPS_FL_INITIALIZED |
7288 static int __init ftrace_nodyn_init(void)
7293 core_initcall(ftrace_nodyn_init);
7295 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7296 static inline void ftrace_startup_all(int command) { }
7298 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7302 #endif /* CONFIG_DYNAMIC_FTRACE */
7304 __init void ftrace_init_global_array_ops(struct trace_array *tr)
7306 tr->ops = &global_ops;
7307 tr->ops->private = tr;
7308 ftrace_init_trace_array(tr);
7311 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7313 /* If we filter on pids, update to use the pid function */
7314 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7315 if (WARN_ON(tr->ops->func != ftrace_stub))
7316 printk("ftrace ops had %pS for function\n",
7319 tr->ops->func = func;
7320 tr->ops->private = tr;
7323 void ftrace_reset_array_ops(struct trace_array *tr)
7325 tr->ops->func = ftrace_stub;
7328 static nokprobe_inline void
7329 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7330 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7332 struct pt_regs *regs = ftrace_get_regs(fregs);
7333 struct ftrace_ops *op;
7337 * The ftrace_test_and_set_recursion() will disable preemption,
7338 * which is required since some of the ops may be dynamically
7339 * allocated, they must be freed after a synchronize_rcu().
7341 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7345 do_for_each_ftrace_op(op, ftrace_ops_list) {
7346 /* Stub functions don't need to be called nor tested */
7347 if (op->flags & FTRACE_OPS_FL_STUB)
7350 * Check the following for each ops before calling their func:
7351 * if RCU flag is set, then rcu_is_watching() must be true
7352 * Otherwise test if the ip matches the ops filter
7354 * If any of the above fails then the op->func() is not executed.
7356 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7357 ftrace_ops_test(op, ip, regs)) {
7358 if (FTRACE_WARN_ON(!op->func)) {
7359 pr_warn("op=%p %pS\n", op, op);
7362 op->func(ip, parent_ip, op, fregs);
7364 } while_for_each_ftrace_op(op);
7366 trace_clear_recursion(bit);
7370 * Some archs only support passing ip and parent_ip. Even though
7371 * the list function ignores the op parameter, we do not want any
7372 * C side effects, where a function is called without the caller
7373 * sending a third parameter.
7374 * Archs are to support both the regs and ftrace_ops at the same time.
7375 * If they support ftrace_ops, it is assumed they support regs.
7376 * If call backs want to use regs, they must either check for regs
7377 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7378 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7379 * An architecture can pass partial regs with ftrace_ops and still
7380 * set the ARCH_SUPPORTS_FTRACE_OPS.
7382 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7383 * arch_ftrace_ops_list_func.
7385 #if ARCH_SUPPORTS_FTRACE_OPS
7386 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7387 struct ftrace_ops *op, struct ftrace_regs *fregs)
7389 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7392 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7394 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7397 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7400 * If there's only one function registered but it does not support
7401 * recursion, needs RCU protection, then this function will be called
7402 * by the mcount trampoline.
7404 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7405 struct ftrace_ops *op, struct ftrace_regs *fregs)
7409 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7413 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7414 op->func(ip, parent_ip, op, fregs);
7416 trace_clear_recursion(bit);
7418 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7421 * ftrace_ops_get_func - get the function a trampoline should call
7422 * @ops: the ops to get the function for
7424 * Normally the mcount trampoline will call the ops->func, but there
7425 * are times that it should not. For example, if the ops does not
7426 * have its own recursion protection, then it should call the
7427 * ftrace_ops_assist_func() instead.
7429 * Returns the function that the trampoline should call for @ops.
7431 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7434 * If the function does not handle recursion or needs to be RCU safe,
7435 * then we need to call the assist handler.
7437 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7439 return ftrace_ops_assist_func;
7445 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7446 struct task_struct *prev,
7447 struct task_struct *next,
7448 unsigned int prev_state)
7450 struct trace_array *tr = data;
7451 struct trace_pid_list *pid_list;
7452 struct trace_pid_list *no_pid_list;
7454 pid_list = rcu_dereference_sched(tr->function_pids);
7455 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7457 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7458 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7461 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7466 ftrace_pid_follow_sched_process_fork(void *data,
7467 struct task_struct *self,
7468 struct task_struct *task)
7470 struct trace_pid_list *pid_list;
7471 struct trace_array *tr = data;
7473 pid_list = rcu_dereference_sched(tr->function_pids);
7474 trace_filter_add_remove_task(pid_list, self, task);
7476 pid_list = rcu_dereference_sched(tr->function_no_pids);
7477 trace_filter_add_remove_task(pid_list, self, task);
7481 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7483 struct trace_pid_list *pid_list;
7484 struct trace_array *tr = data;
7486 pid_list = rcu_dereference_sched(tr->function_pids);
7487 trace_filter_add_remove_task(pid_list, NULL, task);
7489 pid_list = rcu_dereference_sched(tr->function_no_pids);
7490 trace_filter_add_remove_task(pid_list, NULL, task);
7493 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7496 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7498 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7501 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7503 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7508 static void clear_ftrace_pids(struct trace_array *tr, int type)
7510 struct trace_pid_list *pid_list;
7511 struct trace_pid_list *no_pid_list;
7514 pid_list = rcu_dereference_protected(tr->function_pids,
7515 lockdep_is_held(&ftrace_lock));
7516 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7517 lockdep_is_held(&ftrace_lock));
7519 /* Make sure there's something to do */
7520 if (!pid_type_enabled(type, pid_list, no_pid_list))
7523 /* See if the pids still need to be checked after this */
7524 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7525 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7526 for_each_possible_cpu(cpu)
7527 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7530 if (type & TRACE_PIDS)
7531 rcu_assign_pointer(tr->function_pids, NULL);
7533 if (type & TRACE_NO_PIDS)
7534 rcu_assign_pointer(tr->function_no_pids, NULL);
7536 /* Wait till all users are no longer using pid filtering */
7539 if ((type & TRACE_PIDS) && pid_list)
7540 trace_pid_list_free(pid_list);
7542 if ((type & TRACE_NO_PIDS) && no_pid_list)
7543 trace_pid_list_free(no_pid_list);
7546 void ftrace_clear_pids(struct trace_array *tr)
7548 mutex_lock(&ftrace_lock);
7550 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7552 mutex_unlock(&ftrace_lock);
7555 static void ftrace_pid_reset(struct trace_array *tr, int type)
7557 mutex_lock(&ftrace_lock);
7558 clear_ftrace_pids(tr, type);
7560 ftrace_update_pid_func();
7561 ftrace_startup_all(0);
7563 mutex_unlock(&ftrace_lock);
7566 /* Greater than any max PID */
7567 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7569 static void *fpid_start(struct seq_file *m, loff_t *pos)
7572 struct trace_pid_list *pid_list;
7573 struct trace_array *tr = m->private;
7575 mutex_lock(&ftrace_lock);
7576 rcu_read_lock_sched();
7578 pid_list = rcu_dereference_sched(tr->function_pids);
7581 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7583 return trace_pid_start(pid_list, pos);
7586 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7588 struct trace_array *tr = m->private;
7589 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7591 if (v == FTRACE_NO_PIDS) {
7595 return trace_pid_next(pid_list, v, pos);
7598 static void fpid_stop(struct seq_file *m, void *p)
7601 rcu_read_unlock_sched();
7602 mutex_unlock(&ftrace_lock);
7605 static int fpid_show(struct seq_file *m, void *v)
7607 if (v == FTRACE_NO_PIDS) {
7608 seq_puts(m, "no pid\n");
7612 return trace_pid_show(m, v);
7615 static const struct seq_operations ftrace_pid_sops = {
7616 .start = fpid_start,
7622 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7625 struct trace_pid_list *pid_list;
7626 struct trace_array *tr = m->private;
7628 mutex_lock(&ftrace_lock);
7629 rcu_read_lock_sched();
7631 pid_list = rcu_dereference_sched(tr->function_no_pids);
7634 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7636 return trace_pid_start(pid_list, pos);
7639 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7641 struct trace_array *tr = m->private;
7642 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7644 if (v == FTRACE_NO_PIDS) {
7648 return trace_pid_next(pid_list, v, pos);
7651 static const struct seq_operations ftrace_no_pid_sops = {
7652 .start = fnpid_start,
7658 static int pid_open(struct inode *inode, struct file *file, int type)
7660 const struct seq_operations *seq_ops;
7661 struct trace_array *tr = inode->i_private;
7665 ret = tracing_check_open_get_tr(tr);
7669 if ((file->f_mode & FMODE_WRITE) &&
7670 (file->f_flags & O_TRUNC))
7671 ftrace_pid_reset(tr, type);
7675 seq_ops = &ftrace_pid_sops;
7678 seq_ops = &ftrace_no_pid_sops;
7681 trace_array_put(tr);
7686 ret = seq_open(file, seq_ops);
7688 trace_array_put(tr);
7690 m = file->private_data;
7691 /* copy tr over to seq ops */
7699 ftrace_pid_open(struct inode *inode, struct file *file)
7701 return pid_open(inode, file, TRACE_PIDS);
7705 ftrace_no_pid_open(struct inode *inode, struct file *file)
7707 return pid_open(inode, file, TRACE_NO_PIDS);
7710 static void ignore_task_cpu(void *data)
7712 struct trace_array *tr = data;
7713 struct trace_pid_list *pid_list;
7714 struct trace_pid_list *no_pid_list;
7717 * This function is called by on_each_cpu() while the
7718 * event_mutex is held.
7720 pid_list = rcu_dereference_protected(tr->function_pids,
7721 mutex_is_locked(&ftrace_lock));
7722 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7723 mutex_is_locked(&ftrace_lock));
7725 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7726 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7729 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7734 pid_write(struct file *filp, const char __user *ubuf,
7735 size_t cnt, loff_t *ppos, int type)
7737 struct seq_file *m = filp->private_data;
7738 struct trace_array *tr = m->private;
7739 struct trace_pid_list *filtered_pids;
7740 struct trace_pid_list *other_pids;
7741 struct trace_pid_list *pid_list;
7747 mutex_lock(&ftrace_lock);
7751 filtered_pids = rcu_dereference_protected(tr->function_pids,
7752 lockdep_is_held(&ftrace_lock));
7753 other_pids = rcu_dereference_protected(tr->function_no_pids,
7754 lockdep_is_held(&ftrace_lock));
7757 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7758 lockdep_is_held(&ftrace_lock));
7759 other_pids = rcu_dereference_protected(tr->function_pids,
7760 lockdep_is_held(&ftrace_lock));
7768 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7774 rcu_assign_pointer(tr->function_pids, pid_list);
7777 rcu_assign_pointer(tr->function_no_pids, pid_list);
7782 if (filtered_pids) {
7784 trace_pid_list_free(filtered_pids);
7785 } else if (pid_list && !other_pids) {
7786 /* Register a probe to set whether to ignore the tracing of a task */
7787 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7791 * Ignoring of pids is done at task switch. But we have to
7792 * check for those tasks that are currently running.
7793 * Always do this in case a pid was appended or removed.
7795 on_each_cpu(ignore_task_cpu, tr, 1);
7797 ftrace_update_pid_func();
7798 ftrace_startup_all(0);
7800 mutex_unlock(&ftrace_lock);
7809 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7810 size_t cnt, loff_t *ppos)
7812 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7816 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7817 size_t cnt, loff_t *ppos)
7819 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7823 ftrace_pid_release(struct inode *inode, struct file *file)
7825 struct trace_array *tr = inode->i_private;
7827 trace_array_put(tr);
7829 return seq_release(inode, file);
7832 static const struct file_operations ftrace_pid_fops = {
7833 .open = ftrace_pid_open,
7834 .write = ftrace_pid_write,
7836 .llseek = tracing_lseek,
7837 .release = ftrace_pid_release,
7840 static const struct file_operations ftrace_no_pid_fops = {
7841 .open = ftrace_no_pid_open,
7842 .write = ftrace_no_pid_write,
7844 .llseek = tracing_lseek,
7845 .release = ftrace_pid_release,
7848 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7850 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7851 tr, &ftrace_pid_fops);
7852 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7853 d_tracer, tr, &ftrace_no_pid_fops);
7856 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7857 struct dentry *d_tracer)
7859 /* Only the top level directory has the dyn_tracefs and profile */
7860 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7862 ftrace_init_dyn_tracefs(d_tracer);
7863 ftrace_profile_tracefs(d_tracer);
7867 * ftrace_kill - kill ftrace
7869 * This function should be used by panic code. It stops ftrace
7870 * but in a not so nice way. If you need to simply kill ftrace
7871 * from a non-atomic section, use ftrace_kill.
7873 void ftrace_kill(void)
7875 ftrace_disabled = 1;
7877 ftrace_trace_function = ftrace_stub;
7881 * ftrace_is_dead - Test if ftrace is dead or not.
7883 * Returns 1 if ftrace is "dead", zero otherwise.
7885 int ftrace_is_dead(void)
7887 return ftrace_disabled;
7890 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7892 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7893 * it doesn't conflict with any direct ftrace_ops. If there is existing
7894 * direct ftrace_ops on a kernel function being patched, call
7895 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7897 * @ops: ftrace_ops being registered.
7901 * Negative on failure.
7903 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7905 struct ftrace_func_entry *entry;
7906 struct ftrace_hash *hash;
7907 struct ftrace_ops *op;
7910 lockdep_assert_held_once(&direct_mutex);
7912 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7915 hash = ops->func_hash->filter_hash;
7916 size = 1 << hash->size_bits;
7917 for (i = 0; i < size; i++) {
7918 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7919 unsigned long ip = entry->ip;
7920 bool found_op = false;
7922 mutex_lock(&ftrace_lock);
7923 do_for_each_ftrace_op(op, ftrace_ops_list) {
7924 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7926 if (ops_references_ip(op, ip)) {
7930 } while_for_each_ftrace_op(op);
7931 mutex_unlock(&ftrace_lock);
7937 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7948 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7949 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7952 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7954 struct ftrace_func_entry *entry;
7955 struct ftrace_hash *hash;
7956 struct ftrace_ops *op;
7959 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7962 mutex_lock(&direct_mutex);
7964 hash = ops->func_hash->filter_hash;
7965 size = 1 << hash->size_bits;
7966 for (i = 0; i < size; i++) {
7967 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7968 unsigned long ip = entry->ip;
7969 bool found_op = false;
7971 mutex_lock(&ftrace_lock);
7972 do_for_each_ftrace_op(op, ftrace_ops_list) {
7973 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7975 if (ops_references_ip(op, ip)) {
7979 } while_for_each_ftrace_op(op);
7980 mutex_unlock(&ftrace_lock);
7982 /* The cleanup is optional, ignore any errors */
7983 if (found_op && op->ops_func)
7984 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
7987 mutex_unlock(&direct_mutex);
7990 #define lock_direct_mutex() mutex_lock(&direct_mutex)
7991 #define unlock_direct_mutex() mutex_unlock(&direct_mutex)
7993 #else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
7995 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8000 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8004 #define lock_direct_mutex() do { } while (0)
8005 #define unlock_direct_mutex() do { } while (0)
8007 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8010 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8012 static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8016 ftrace_ops_init(ops);
8018 mutex_lock(&ftrace_lock);
8020 ret = ftrace_startup(ops, 0);
8022 mutex_unlock(&ftrace_lock);
8028 * register_ftrace_function - register a function for profiling
8029 * @ops: ops structure that holds the function for profiling.
8031 * Register a function to be called by all functions in the
8034 * Note: @ops->func and all the functions it calls must be labeled
8035 * with "notrace", otherwise it will go into a
8038 int register_ftrace_function(struct ftrace_ops *ops)
8042 lock_direct_mutex();
8043 ret = prepare_direct_functions_for_ipmodify(ops);
8047 ret = register_ftrace_function_nolock(ops);
8050 unlock_direct_mutex();
8053 EXPORT_SYMBOL_GPL(register_ftrace_function);
8056 * unregister_ftrace_function - unregister a function for profiling.
8057 * @ops: ops structure that holds the function to unregister
8059 * Unregister a function that was added to be called by ftrace profiling.
8061 int unregister_ftrace_function(struct ftrace_ops *ops)
8065 mutex_lock(&ftrace_lock);
8066 ret = ftrace_shutdown(ops, 0);
8067 mutex_unlock(&ftrace_lock);
8069 cleanup_direct_functions_after_ipmodify(ops);
8072 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8074 static int symbols_cmp(const void *a, const void *b)
8076 const char **str_a = (const char **) a;
8077 const char **str_b = (const char **) b;
8079 return strcmp(*str_a, *str_b);
8082 struct kallsyms_data {
8083 unsigned long *addrs;
8089 /* This function gets called for all kernel and module symbols
8090 * and returns 1 in case we resolved all the requested symbols,
8093 static int kallsyms_callback(void *data, const char *name, unsigned long addr)
8095 struct kallsyms_data *args = data;
8099 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8103 idx = sym - args->syms;
8104 if (args->addrs[idx])
8107 if (!ftrace_location(addr))
8110 args->addrs[idx] = addr;
8112 return args->found == args->cnt ? 1 : 0;
8116 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8118 * @sorted_syms: array of symbols pointers symbols to resolve,
8119 * must be alphabetically sorted
8120 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8121 * @addrs: array for storing resulting addresses
8123 * This function looks up addresses for array of symbols provided in
8124 * @syms array (must be alphabetically sorted) and stores them in
8125 * @addrs array, which needs to be big enough to store at least @cnt
8128 * This function returns 0 if all provided symbols are found,
8131 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8133 struct kallsyms_data args;
8136 memset(addrs, 0, sizeof(*addrs) * cnt);
8138 args.syms = sorted_syms;
8142 found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8145 found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8146 return found_all ? 0 : -ESRCH;
8149 #ifdef CONFIG_SYSCTL
8151 #ifdef CONFIG_DYNAMIC_FTRACE
8152 static void ftrace_startup_sysctl(void)
8156 if (unlikely(ftrace_disabled))
8159 /* Force update next time */
8160 saved_ftrace_func = NULL;
8161 /* ftrace_start_up is true if we want ftrace running */
8162 if (ftrace_start_up) {
8163 command = FTRACE_UPDATE_CALLS;
8164 if (ftrace_graph_active)
8165 command |= FTRACE_START_FUNC_RET;
8166 ftrace_startup_enable(command);
8170 static void ftrace_shutdown_sysctl(void)
8174 if (unlikely(ftrace_disabled))
8177 /* ftrace_start_up is true if ftrace is running */
8178 if (ftrace_start_up) {
8179 command = FTRACE_DISABLE_CALLS;
8180 if (ftrace_graph_active)
8181 command |= FTRACE_STOP_FUNC_RET;
8182 ftrace_run_update_code(command);
8186 # define ftrace_startup_sysctl() do { } while (0)
8187 # define ftrace_shutdown_sysctl() do { } while (0)
8188 #endif /* CONFIG_DYNAMIC_FTRACE */
8190 static bool is_permanent_ops_registered(void)
8192 struct ftrace_ops *op;
8194 do_for_each_ftrace_op(op, ftrace_ops_list) {
8195 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8197 } while_for_each_ftrace_op(op);
8203 ftrace_enable_sysctl(struct ctl_table *table, int write,
8204 void *buffer, size_t *lenp, loff_t *ppos)
8208 mutex_lock(&ftrace_lock);
8210 if (unlikely(ftrace_disabled))
8213 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8215 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8218 if (ftrace_enabled) {
8220 /* we are starting ftrace again */
8221 if (rcu_dereference_protected(ftrace_ops_list,
8222 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8223 update_ftrace_function();
8225 ftrace_startup_sysctl();
8228 if (is_permanent_ops_registered()) {
8229 ftrace_enabled = true;
8234 /* stopping ftrace calls (just send to ftrace_stub) */
8235 ftrace_trace_function = ftrace_stub;
8237 ftrace_shutdown_sysctl();
8240 last_ftrace_enabled = !!ftrace_enabled;
8242 mutex_unlock(&ftrace_lock);
8246 static struct ctl_table ftrace_sysctls[] = {
8248 .procname = "ftrace_enabled",
8249 .data = &ftrace_enabled,
8250 .maxlen = sizeof(int),
8252 .proc_handler = ftrace_enable_sysctl,
8257 static int __init ftrace_sysctl_init(void)
8259 register_sysctl_init("kernel", ftrace_sysctls);
8262 late_initcall(ftrace_sysctl_init);