2 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code in the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/sched/task.h>
19 #include <linux/kallsyms.h>
20 #include <linux/seq_file.h>
21 #include <linux/suspend.h>
22 #include <linux/tracefs.h>
23 #include <linux/hardirq.h>
24 #include <linux/kthread.h>
25 #include <linux/uaccess.h>
26 #include <linux/bsearch.h>
27 #include <linux/module.h>
28 #include <linux/ftrace.h>
29 #include <linux/sysctl.h>
30 #include <linux/slab.h>
31 #include <linux/ctype.h>
32 #include <linux/sort.h>
33 #include <linux/list.h>
34 #include <linux/hash.h>
35 #include <linux/rcupdate.h>
36 #include <linux/kprobes.h>
38 #include <trace/events/sched.h>
40 #include <asm/sections.h>
41 #include <asm/setup.h>
43 #include "trace_output.h"
44 #include "trace_stat.h"
46 #define FTRACE_WARN_ON(cond) \
54 #define FTRACE_WARN_ON_ONCE(cond) \
57 if (WARN_ON_ONCE(___r)) \
62 /* hash bits for specific function selection */
63 #define FTRACE_HASH_BITS 7
64 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
65 #define FTRACE_HASH_DEFAULT_BITS 10
66 #define FTRACE_HASH_MAX_BITS 12
68 #ifdef CONFIG_DYNAMIC_FTRACE
69 #define INIT_OPS_HASH(opsname) \
70 .func_hash = &opsname.local_hash, \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
72 #define ASSIGN_OPS_HASH(opsname, val) \
74 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
76 #define INIT_OPS_HASH(opsname)
77 #define ASSIGN_OPS_HASH(opsname, val)
80 static struct ftrace_ops ftrace_list_end __read_mostly = {
82 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
83 INIT_OPS_HASH(ftrace_list_end)
86 /* ftrace_enabled is a method to turn ftrace on or off */
87 int ftrace_enabled __read_mostly;
88 static int last_ftrace_enabled;
90 /* Current function tracing op */
91 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
92 /* What to set function_trace_op to */
93 static struct ftrace_ops *set_function_trace_op;
95 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
97 struct trace_array *tr;
99 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
104 return tr->function_pids != NULL;
107 static void ftrace_update_trampoline(struct ftrace_ops *ops);
110 * ftrace_disabled is set when an anomaly is discovered.
111 * ftrace_disabled is much stronger than ftrace_enabled.
113 static int ftrace_disabled __read_mostly;
115 static DEFINE_MUTEX(ftrace_lock);
117 static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
118 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
119 static struct ftrace_ops global_ops;
121 #if ARCH_SUPPORTS_FTRACE_OPS
122 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
123 struct ftrace_ops *op, struct pt_regs *regs);
125 /* See comment below, where ftrace_ops_list_func is defined */
126 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
127 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
131 * Traverse the ftrace_global_list, invoking all entries. The reason that we
132 * can use rcu_dereference_raw_notrace() is that elements removed from this list
133 * are simply leaked, so there is no need to interact with a grace-period
134 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
135 * concurrent insertions into the ftrace_global_list.
137 * Silly Alpha and silly pointer-speculation compiler optimizations!
139 #define do_for_each_ftrace_op(op, list) \
140 op = rcu_dereference_raw_notrace(list); \
144 * Optimized for just a single item in the list (as that is the normal case).
146 #define while_for_each_ftrace_op(op) \
147 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
148 unlikely((op) != &ftrace_list_end))
150 static inline void ftrace_ops_init(struct ftrace_ops *ops)
152 #ifdef CONFIG_DYNAMIC_FTRACE
153 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
154 mutex_init(&ops->local_hash.regex_lock);
155 ops->func_hash = &ops->local_hash;
156 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
162 * ftrace_nr_registered_ops - return number of ops registered
164 * Returns the number of ftrace_ops registered and tracing functions
166 int ftrace_nr_registered_ops(void)
168 struct ftrace_ops *ops;
171 mutex_lock(&ftrace_lock);
173 for (ops = rcu_dereference_protected(ftrace_ops_list,
174 lockdep_is_held(&ftrace_lock));
175 ops != &ftrace_list_end;
176 ops = rcu_dereference_protected(ops->next,
177 lockdep_is_held(&ftrace_lock)))
180 mutex_unlock(&ftrace_lock);
185 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
186 struct ftrace_ops *op, struct pt_regs *regs)
188 struct trace_array *tr = op->private;
190 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
193 op->saved_func(ip, parent_ip, op, regs);
197 * clear_ftrace_function - reset the ftrace function
199 * This NULLs the ftrace function and in essence stops
200 * tracing. There may be lag
202 void clear_ftrace_function(void)
204 ftrace_trace_function = ftrace_stub;
207 static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
211 for_each_possible_cpu(cpu)
212 *per_cpu_ptr(ops->disabled, cpu) = 1;
215 static int per_cpu_ops_alloc(struct ftrace_ops *ops)
217 int __percpu *disabled;
219 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
222 disabled = alloc_percpu(int);
226 ops->disabled = disabled;
227 per_cpu_ops_disable_all(ops);
231 static void ftrace_sync(struct work_struct *work)
234 * This function is just a stub to implement a hard force
235 * of synchronize_sched(). This requires synchronizing
236 * tasks even in userspace and idle.
238 * Yes, function tracing is rude.
242 static void ftrace_sync_ipi(void *data)
244 /* Probably not needed, but do it anyway */
248 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
249 static void update_function_graph_func(void);
251 /* Both enabled by default (can be cleared by function_graph tracer flags */
252 static bool fgraph_sleep_time = true;
253 static bool fgraph_graph_time = true;
256 static inline void update_function_graph_func(void) { }
260 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
263 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
264 * then it needs to call the list anyway.
266 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
267 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
268 return ftrace_ops_list_func;
270 return ftrace_ops_get_func(ops);
273 static void update_ftrace_function(void)
278 * Prepare the ftrace_ops that the arch callback will use.
279 * If there's only one ftrace_ops registered, the ftrace_ops_list
280 * will point to the ops we want.
282 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
283 lockdep_is_held(&ftrace_lock));
285 /* If there's no ftrace_ops registered, just call the stub function */
286 if (set_function_trace_op == &ftrace_list_end) {
290 * If we are at the end of the list and this ops is
291 * recursion safe and not dynamic and the arch supports passing ops,
292 * then have the mcount trampoline call the function directly.
294 } else if (rcu_dereference_protected(ftrace_ops_list->next,
295 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
296 func = ftrace_ops_get_list_func(ftrace_ops_list);
299 /* Just use the default ftrace_ops */
300 set_function_trace_op = &ftrace_list_end;
301 func = ftrace_ops_list_func;
304 update_function_graph_func();
306 /* If there's no change, then do nothing more here */
307 if (ftrace_trace_function == func)
311 * If we are using the list function, it doesn't care
312 * about the function_trace_ops.
314 if (func == ftrace_ops_list_func) {
315 ftrace_trace_function = func;
317 * Don't even bother setting function_trace_ops,
318 * it would be racy to do so anyway.
323 #ifndef CONFIG_DYNAMIC_FTRACE
325 * For static tracing, we need to be a bit more careful.
326 * The function change takes affect immediately. Thus,
327 * we need to coorditate the setting of the function_trace_ops
328 * with the setting of the ftrace_trace_function.
330 * Set the function to the list ops, which will call the
331 * function we want, albeit indirectly, but it handles the
332 * ftrace_ops and doesn't depend on function_trace_op.
334 ftrace_trace_function = ftrace_ops_list_func;
336 * Make sure all CPUs see this. Yes this is slow, but static
337 * tracing is slow and nasty to have enabled.
339 schedule_on_each_cpu(ftrace_sync);
340 /* Now all cpus are using the list ops. */
341 function_trace_op = set_function_trace_op;
342 /* Make sure the function_trace_op is visible on all CPUs */
344 /* Nasty way to force a rmb on all cpus */
345 smp_call_function(ftrace_sync_ipi, NULL, 1);
346 /* OK, we are all set to update the ftrace_trace_function now! */
347 #endif /* !CONFIG_DYNAMIC_FTRACE */
349 ftrace_trace_function = func;
352 int using_ftrace_ops_list_func(void)
354 return ftrace_trace_function == ftrace_ops_list_func;
357 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
358 struct ftrace_ops *ops)
360 rcu_assign_pointer(ops->next, *list);
363 * We are entering ops into the list but another
364 * CPU might be walking that list. We need to make sure
365 * the ops->next pointer is valid before another CPU sees
366 * the ops pointer included into the list.
368 rcu_assign_pointer(*list, ops);
371 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
372 struct ftrace_ops *ops)
374 struct ftrace_ops **p;
377 * If we are removing the last function, then simply point
378 * to the ftrace_stub.
380 if (rcu_dereference_protected(*list,
381 lockdep_is_held(&ftrace_lock)) == ops &&
382 rcu_dereference_protected(ops->next,
383 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
384 *list = &ftrace_list_end;
388 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
399 static void ftrace_update_trampoline(struct ftrace_ops *ops);
401 static int __register_ftrace_function(struct ftrace_ops *ops)
403 if (ops->flags & FTRACE_OPS_FL_DELETED)
406 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
409 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
411 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
412 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
413 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
415 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
416 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
419 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
420 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
423 if (!core_kernel_data((unsigned long)ops))
424 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
426 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
427 if (per_cpu_ops_alloc(ops))
431 add_ftrace_ops(&ftrace_ops_list, ops);
433 /* Always save the function, and reset at unregistering */
434 ops->saved_func = ops->func;
436 if (ftrace_pids_enabled(ops))
437 ops->func = ftrace_pid_func;
439 ftrace_update_trampoline(ops);
442 update_ftrace_function();
447 static int __unregister_ftrace_function(struct ftrace_ops *ops)
451 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
454 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
460 update_ftrace_function();
462 ops->func = ops->saved_func;
467 static void ftrace_update_pid_func(void)
469 struct ftrace_ops *op;
471 /* Only do something if we are tracing something */
472 if (ftrace_trace_function == ftrace_stub)
475 do_for_each_ftrace_op(op, ftrace_ops_list) {
476 if (op->flags & FTRACE_OPS_FL_PID) {
477 op->func = ftrace_pids_enabled(op) ?
478 ftrace_pid_func : op->saved_func;
479 ftrace_update_trampoline(op);
481 } while_for_each_ftrace_op(op);
483 update_ftrace_function();
486 #ifdef CONFIG_FUNCTION_PROFILER
487 struct ftrace_profile {
488 struct hlist_node node;
490 unsigned long counter;
491 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
492 unsigned long long time;
493 unsigned long long time_squared;
497 struct ftrace_profile_page {
498 struct ftrace_profile_page *next;
500 struct ftrace_profile records[];
503 struct ftrace_profile_stat {
505 struct hlist_head *hash;
506 struct ftrace_profile_page *pages;
507 struct ftrace_profile_page *start;
508 struct tracer_stat stat;
511 #define PROFILE_RECORDS_SIZE \
512 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
514 #define PROFILES_PER_PAGE \
515 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
517 static int ftrace_profile_enabled __read_mostly;
519 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
520 static DEFINE_MUTEX(ftrace_profile_lock);
522 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
524 #define FTRACE_PROFILE_HASH_BITS 10
525 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
528 function_stat_next(void *v, int idx)
530 struct ftrace_profile *rec = v;
531 struct ftrace_profile_page *pg;
533 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
539 if ((void *)rec >= (void *)&pg->records[pg->index]) {
543 rec = &pg->records[0];
551 static void *function_stat_start(struct tracer_stat *trace)
553 struct ftrace_profile_stat *stat =
554 container_of(trace, struct ftrace_profile_stat, stat);
556 if (!stat || !stat->start)
559 return function_stat_next(&stat->start->records[0], 0);
562 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
563 /* function graph compares on total time */
564 static int function_stat_cmp(void *p1, void *p2)
566 struct ftrace_profile *a = p1;
567 struct ftrace_profile *b = p2;
569 if (a->time < b->time)
571 if (a->time > b->time)
577 /* not function graph compares against hits */
578 static int function_stat_cmp(void *p1, void *p2)
580 struct ftrace_profile *a = p1;
581 struct ftrace_profile *b = p2;
583 if (a->counter < b->counter)
585 if (a->counter > b->counter)
592 static int function_stat_headers(struct seq_file *m)
594 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
595 seq_puts(m, " Function "
598 "--- ---- --- ---\n");
600 seq_puts(m, " Function Hit\n"
606 static int function_stat_show(struct seq_file *m, void *v)
608 struct ftrace_profile *rec = v;
609 char str[KSYM_SYMBOL_LEN];
611 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
612 static struct trace_seq s;
613 unsigned long long avg;
614 unsigned long long stddev;
616 mutex_lock(&ftrace_profile_lock);
618 /* we raced with function_profile_reset() */
619 if (unlikely(rec->counter == 0)) {
624 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
625 avg = div64_ul(rec->time, rec->counter);
626 if (tracing_thresh && (avg < tracing_thresh))
630 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
631 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
633 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
636 /* Sample standard deviation (s^2) */
637 if (rec->counter <= 1)
641 * Apply Welford's method:
642 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
644 stddev = rec->counter * rec->time_squared -
645 rec->time * rec->time;
648 * Divide only 1000 for ns^2 -> us^2 conversion.
649 * trace_print_graph_duration will divide 1000 again.
651 stddev = div64_ul(stddev,
652 rec->counter * (rec->counter - 1) * 1000);
656 trace_print_graph_duration(rec->time, &s);
657 trace_seq_puts(&s, " ");
658 trace_print_graph_duration(avg, &s);
659 trace_seq_puts(&s, " ");
660 trace_print_graph_duration(stddev, &s);
661 trace_print_seq(m, &s);
665 mutex_unlock(&ftrace_profile_lock);
670 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
672 struct ftrace_profile_page *pg;
674 pg = stat->pages = stat->start;
677 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
682 memset(stat->hash, 0,
683 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
686 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
688 struct ftrace_profile_page *pg;
693 /* If we already allocated, do nothing */
697 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
701 #ifdef CONFIG_DYNAMIC_FTRACE
702 functions = ftrace_update_tot_cnt;
705 * We do not know the number of functions that exist because
706 * dynamic tracing is what counts them. With past experience
707 * we have around 20K functions. That should be more than enough.
708 * It is highly unlikely we will execute every function in
714 pg = stat->start = stat->pages;
716 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
718 for (i = 1; i < pages; i++) {
719 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
730 unsigned long tmp = (unsigned long)pg;
742 static int ftrace_profile_init_cpu(int cpu)
744 struct ftrace_profile_stat *stat;
747 stat = &per_cpu(ftrace_profile_stats, cpu);
750 /* If the profile is already created, simply reset it */
751 ftrace_profile_reset(stat);
756 * We are profiling all functions, but usually only a few thousand
757 * functions are hit. We'll make a hash of 1024 items.
759 size = FTRACE_PROFILE_HASH_SIZE;
761 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
766 /* Preallocate the function profiling pages */
767 if (ftrace_profile_pages_init(stat) < 0) {
776 static int ftrace_profile_init(void)
781 for_each_possible_cpu(cpu) {
782 ret = ftrace_profile_init_cpu(cpu);
790 /* interrupts must be disabled */
791 static struct ftrace_profile *
792 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
794 struct ftrace_profile *rec;
795 struct hlist_head *hhd;
798 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
799 hhd = &stat->hash[key];
801 if (hlist_empty(hhd))
804 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
812 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
813 struct ftrace_profile *rec)
817 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
818 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
822 * The memory is already allocated, this simply finds a new record to use.
824 static struct ftrace_profile *
825 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
827 struct ftrace_profile *rec = NULL;
829 /* prevent recursion (from NMIs) */
830 if (atomic_inc_return(&stat->disabled) != 1)
834 * Try to find the function again since an NMI
835 * could have added it
837 rec = ftrace_find_profiled_func(stat, ip);
841 if (stat->pages->index == PROFILES_PER_PAGE) {
842 if (!stat->pages->next)
844 stat->pages = stat->pages->next;
847 rec = &stat->pages->records[stat->pages->index++];
849 ftrace_add_profile(stat, rec);
852 atomic_dec(&stat->disabled);
858 function_profile_call(unsigned long ip, unsigned long parent_ip,
859 struct ftrace_ops *ops, struct pt_regs *regs)
861 struct ftrace_profile_stat *stat;
862 struct ftrace_profile *rec;
865 if (!ftrace_profile_enabled)
868 local_irq_save(flags);
870 stat = this_cpu_ptr(&ftrace_profile_stats);
871 if (!stat->hash || !ftrace_profile_enabled)
874 rec = ftrace_find_profiled_func(stat, ip);
876 rec = ftrace_profile_alloc(stat, ip);
883 local_irq_restore(flags);
886 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
887 static int profile_graph_entry(struct ftrace_graph_ent *trace)
889 int index = trace->depth;
891 function_profile_call(trace->func, 0, NULL, NULL);
893 /* If function graph is shutting down, ret_stack can be NULL */
894 if (!current->ret_stack)
897 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
898 current->ret_stack[index].subtime = 0;
903 static void profile_graph_return(struct ftrace_graph_ret *trace)
905 struct ftrace_profile_stat *stat;
906 unsigned long long calltime;
907 struct ftrace_profile *rec;
910 local_irq_save(flags);
911 stat = this_cpu_ptr(&ftrace_profile_stats);
912 if (!stat->hash || !ftrace_profile_enabled)
915 /* If the calltime was zero'd ignore it */
916 if (!trace->calltime)
919 calltime = trace->rettime - trace->calltime;
921 if (!fgraph_graph_time) {
924 index = trace->depth;
926 /* Append this call time to the parent time to subtract */
928 current->ret_stack[index - 1].subtime += calltime;
930 if (current->ret_stack[index].subtime < calltime)
931 calltime -= current->ret_stack[index].subtime;
936 rec = ftrace_find_profiled_func(stat, trace->func);
938 rec->time += calltime;
939 rec->time_squared += calltime * calltime;
943 local_irq_restore(flags);
946 static int register_ftrace_profiler(void)
948 return register_ftrace_graph(&profile_graph_return,
949 &profile_graph_entry);
952 static void unregister_ftrace_profiler(void)
954 unregister_ftrace_graph();
957 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
958 .func = function_profile_call,
959 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
960 INIT_OPS_HASH(ftrace_profile_ops)
963 static int register_ftrace_profiler(void)
965 return register_ftrace_function(&ftrace_profile_ops);
968 static void unregister_ftrace_profiler(void)
970 unregister_ftrace_function(&ftrace_profile_ops);
972 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
975 ftrace_profile_write(struct file *filp, const char __user *ubuf,
976 size_t cnt, loff_t *ppos)
981 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
987 mutex_lock(&ftrace_profile_lock);
988 if (ftrace_profile_enabled ^ val) {
990 ret = ftrace_profile_init();
996 ret = register_ftrace_profiler();
1001 ftrace_profile_enabled = 1;
1003 ftrace_profile_enabled = 0;
1005 * unregister_ftrace_profiler calls stop_machine
1006 * so this acts like an synchronize_sched.
1008 unregister_ftrace_profiler();
1012 mutex_unlock(&ftrace_profile_lock);
1020 ftrace_profile_read(struct file *filp, char __user *ubuf,
1021 size_t cnt, loff_t *ppos)
1023 char buf[64]; /* big enough to hold a number */
1026 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1027 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1030 static const struct file_operations ftrace_profile_fops = {
1031 .open = tracing_open_generic,
1032 .read = ftrace_profile_read,
1033 .write = ftrace_profile_write,
1034 .llseek = default_llseek,
1037 /* used to initialize the real stat files */
1038 static struct tracer_stat function_stats __initdata = {
1039 .name = "functions",
1040 .stat_start = function_stat_start,
1041 .stat_next = function_stat_next,
1042 .stat_cmp = function_stat_cmp,
1043 .stat_headers = function_stat_headers,
1044 .stat_show = function_stat_show
1047 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1049 struct ftrace_profile_stat *stat;
1050 struct dentry *entry;
1055 for_each_possible_cpu(cpu) {
1056 stat = &per_cpu(ftrace_profile_stats, cpu);
1058 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1061 * The files created are permanent, if something happens
1062 * we still do not free memory.
1065 "Could not allocate stat file for cpu %d\n",
1069 stat->stat = function_stats;
1070 stat->stat.name = name;
1071 ret = register_stat_tracer(&stat->stat);
1074 "Could not register function stat for cpu %d\n",
1081 entry = tracefs_create_file("function_profile_enabled", 0644,
1082 d_tracer, NULL, &ftrace_profile_fops);
1084 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1087 #else /* CONFIG_FUNCTION_PROFILER */
1088 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1091 #endif /* CONFIG_FUNCTION_PROFILER */
1093 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1095 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1096 static int ftrace_graph_active;
1098 # define ftrace_graph_active 0
1101 #ifdef CONFIG_DYNAMIC_FTRACE
1103 static struct ftrace_ops *removed_ops;
1106 * Set when doing a global update, like enabling all recs or disabling them.
1107 * It is not set when just updating a single ftrace_ops.
1109 static bool update_all_ops;
1111 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1112 # error Dynamic ftrace depends on MCOUNT_RECORD
1115 struct ftrace_func_entry {
1116 struct hlist_node hlist;
1120 struct ftrace_func_probe {
1121 struct ftrace_probe_ops *probe_ops;
1122 struct ftrace_ops ops;
1123 struct trace_array *tr;
1124 struct list_head list;
1130 * We make these constant because no one should touch them,
1131 * but they are used as the default "empty hash", to avoid allocating
1132 * it all the time. These are in a read only section such that if
1133 * anyone does try to modify it, it will cause an exception.
1135 static const struct hlist_head empty_buckets[1];
1136 static const struct ftrace_hash empty_hash = {
1137 .buckets = (struct hlist_head *)empty_buckets,
1139 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1141 static struct ftrace_ops global_ops = {
1142 .func = ftrace_stub,
1143 .local_hash.notrace_hash = EMPTY_HASH,
1144 .local_hash.filter_hash = EMPTY_HASH,
1145 INIT_OPS_HASH(global_ops)
1146 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1147 FTRACE_OPS_FL_INITIALIZED |
1152 * This is used by __kernel_text_address() to return true if the
1153 * address is on a dynamically allocated trampoline that would
1154 * not return true for either core_kernel_text() or
1155 * is_module_text_address().
1157 bool is_ftrace_trampoline(unsigned long addr)
1159 struct ftrace_ops *op;
1163 * Some of the ops may be dynamically allocated,
1164 * they are freed after a synchronize_sched().
1166 preempt_disable_notrace();
1168 do_for_each_ftrace_op(op, ftrace_ops_list) {
1170 * This is to check for dynamically allocated trampolines.
1171 * Trampolines that are in kernel text will have
1172 * core_kernel_text() return true.
1174 if (op->trampoline && op->trampoline_size)
1175 if (addr >= op->trampoline &&
1176 addr < op->trampoline + op->trampoline_size) {
1180 } while_for_each_ftrace_op(op);
1183 preempt_enable_notrace();
1188 struct ftrace_page {
1189 struct ftrace_page *next;
1190 struct dyn_ftrace *records;
1195 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1196 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1198 /* estimate from running different kernels */
1199 #define NR_TO_INIT 10000
1201 static struct ftrace_page *ftrace_pages_start;
1202 static struct ftrace_page *ftrace_pages;
1204 static __always_inline unsigned long
1205 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1207 if (hash->size_bits > 0)
1208 return hash_long(ip, hash->size_bits);
1213 /* Only use this function if ftrace_hash_empty() has already been tested */
1214 static __always_inline struct ftrace_func_entry *
1215 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1218 struct ftrace_func_entry *entry;
1219 struct hlist_head *hhd;
1221 key = ftrace_hash_key(hash, ip);
1222 hhd = &hash->buckets[key];
1224 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1225 if (entry->ip == ip)
1232 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1233 * @hash: The hash to look at
1234 * @ip: The instruction pointer to test
1236 * Search a given @hash to see if a given instruction pointer (@ip)
1239 * Returns the entry that holds the @ip if found. NULL otherwise.
1241 struct ftrace_func_entry *
1242 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1244 if (ftrace_hash_empty(hash))
1247 return __ftrace_lookup_ip(hash, ip);
1250 static void __add_hash_entry(struct ftrace_hash *hash,
1251 struct ftrace_func_entry *entry)
1253 struct hlist_head *hhd;
1256 key = ftrace_hash_key(hash, entry->ip);
1257 hhd = &hash->buckets[key];
1258 hlist_add_head(&entry->hlist, hhd);
1262 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1264 struct ftrace_func_entry *entry;
1266 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1271 __add_hash_entry(hash, entry);
1277 free_hash_entry(struct ftrace_hash *hash,
1278 struct ftrace_func_entry *entry)
1280 hlist_del(&entry->hlist);
1286 remove_hash_entry(struct ftrace_hash *hash,
1287 struct ftrace_func_entry *entry)
1289 hlist_del_rcu(&entry->hlist);
1293 static void ftrace_hash_clear(struct ftrace_hash *hash)
1295 struct hlist_head *hhd;
1296 struct hlist_node *tn;
1297 struct ftrace_func_entry *entry;
1298 int size = 1 << hash->size_bits;
1304 for (i = 0; i < size; i++) {
1305 hhd = &hash->buckets[i];
1306 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1307 free_hash_entry(hash, entry);
1309 FTRACE_WARN_ON(hash->count);
1312 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1314 list_del(&ftrace_mod->list);
1315 kfree(ftrace_mod->module);
1316 kfree(ftrace_mod->func);
1320 static void clear_ftrace_mod_list(struct list_head *head)
1322 struct ftrace_mod_load *p, *n;
1324 /* stack tracer isn't supported yet */
1328 mutex_lock(&ftrace_lock);
1329 list_for_each_entry_safe(p, n, head, list)
1331 mutex_unlock(&ftrace_lock);
1334 static void free_ftrace_hash(struct ftrace_hash *hash)
1336 if (!hash || hash == EMPTY_HASH)
1338 ftrace_hash_clear(hash);
1339 kfree(hash->buckets);
1343 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1345 struct ftrace_hash *hash;
1347 hash = container_of(rcu, struct ftrace_hash, rcu);
1348 free_ftrace_hash(hash);
1351 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1353 if (!hash || hash == EMPTY_HASH)
1355 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1358 void ftrace_free_filter(struct ftrace_ops *ops)
1360 ftrace_ops_init(ops);
1361 free_ftrace_hash(ops->func_hash->filter_hash);
1362 free_ftrace_hash(ops->func_hash->notrace_hash);
1365 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1367 struct ftrace_hash *hash;
1370 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1374 size = 1 << size_bits;
1375 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1377 if (!hash->buckets) {
1382 hash->size_bits = size_bits;
1388 static int ftrace_add_mod(struct trace_array *tr,
1389 const char *func, const char *module,
1392 struct ftrace_mod_load *ftrace_mod;
1393 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1395 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1399 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1400 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1401 ftrace_mod->enable = enable;
1403 if (!ftrace_mod->func || !ftrace_mod->module)
1406 list_add(&ftrace_mod->list, mod_head);
1411 free_ftrace_mod(ftrace_mod);
1416 static struct ftrace_hash *
1417 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1419 struct ftrace_func_entry *entry;
1420 struct ftrace_hash *new_hash;
1425 new_hash = alloc_ftrace_hash(size_bits);
1430 new_hash->flags = hash->flags;
1433 if (ftrace_hash_empty(hash))
1436 size = 1 << hash->size_bits;
1437 for (i = 0; i < size; i++) {
1438 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1439 ret = add_hash_entry(new_hash, entry->ip);
1445 FTRACE_WARN_ON(new_hash->count != hash->count);
1450 free_ftrace_hash(new_hash);
1455 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1457 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1459 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1460 struct ftrace_hash *new_hash);
1462 static struct ftrace_hash *
1463 __ftrace_hash_move(struct ftrace_hash *src)
1465 struct ftrace_func_entry *entry;
1466 struct hlist_node *tn;
1467 struct hlist_head *hhd;
1468 struct ftrace_hash *new_hash;
1469 int size = src->count;
1474 * If the new source is empty, just return the empty_hash.
1476 if (ftrace_hash_empty(src))
1480 * Make the hash size about 1/2 the # found
1482 for (size /= 2; size; size >>= 1)
1485 /* Don't allocate too much */
1486 if (bits > FTRACE_HASH_MAX_BITS)
1487 bits = FTRACE_HASH_MAX_BITS;
1489 new_hash = alloc_ftrace_hash(bits);
1493 new_hash->flags = src->flags;
1495 size = 1 << src->size_bits;
1496 for (i = 0; i < size; i++) {
1497 hhd = &src->buckets[i];
1498 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1499 remove_hash_entry(src, entry);
1500 __add_hash_entry(new_hash, entry);
1508 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1509 struct ftrace_hash **dst, struct ftrace_hash *src)
1511 struct ftrace_hash *new_hash;
1514 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1515 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1518 new_hash = __ftrace_hash_move(src);
1522 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1524 /* IPMODIFY should be updated only when filter_hash updating */
1525 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1527 free_ftrace_hash(new_hash);
1533 * Remove the current set, update the hash and add
1536 ftrace_hash_rec_disable_modify(ops, enable);
1538 rcu_assign_pointer(*dst, new_hash);
1540 ftrace_hash_rec_enable_modify(ops, enable);
1545 static bool hash_contains_ip(unsigned long ip,
1546 struct ftrace_ops_hash *hash)
1549 * The function record is a match if it exists in the filter
1550 * hash and not in the notrace hash. Note, an emty hash is
1551 * considered a match for the filter hash, but an empty
1552 * notrace hash is considered not in the notrace hash.
1554 return (ftrace_hash_empty(hash->filter_hash) ||
1555 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1556 (ftrace_hash_empty(hash->notrace_hash) ||
1557 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1561 * Test the hashes for this ops to see if we want to call
1562 * the ops->func or not.
1564 * It's a match if the ip is in the ops->filter_hash or
1565 * the filter_hash does not exist or is empty,
1567 * the ip is not in the ops->notrace_hash.
1569 * This needs to be called with preemption disabled as
1570 * the hashes are freed with call_rcu_sched().
1573 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1575 struct ftrace_ops_hash hash;
1578 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1580 * There's a small race when adding ops that the ftrace handler
1581 * that wants regs, may be called without them. We can not
1582 * allow that handler to be called if regs is NULL.
1584 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1588 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1589 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1591 if (hash_contains_ip(ip, &hash))
1600 * This is a double for. Do not use 'break' to break out of the loop,
1601 * you must use a goto.
1603 #define do_for_each_ftrace_rec(pg, rec) \
1604 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1606 for (_____i = 0; _____i < pg->index; _____i++) { \
1607 rec = &pg->records[_____i];
1609 #define while_for_each_ftrace_rec() \
1614 static int ftrace_cmp_recs(const void *a, const void *b)
1616 const struct dyn_ftrace *key = a;
1617 const struct dyn_ftrace *rec = b;
1619 if (key->flags < rec->ip)
1621 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1627 * ftrace_location_range - return the first address of a traced location
1628 * if it touches the given ip range
1629 * @start: start of range to search.
1630 * @end: end of range to search (inclusive). @end points to the last byte
1633 * Returns rec->ip if the related ftrace location is a least partly within
1634 * the given address range. That is, the first address of the instruction
1635 * that is either a NOP or call to the function tracer. It checks the ftrace
1636 * internal tables to determine if the address belongs or not.
1638 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1640 struct ftrace_page *pg;
1641 struct dyn_ftrace *rec;
1642 struct dyn_ftrace key;
1645 key.flags = end; /* overload flags, as it is unsigned long */
1647 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1648 if (end < pg->records[0].ip ||
1649 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1651 rec = bsearch(&key, pg->records, pg->index,
1652 sizeof(struct dyn_ftrace),
1662 * ftrace_location - return true if the ip giving is a traced location
1663 * @ip: the instruction pointer to check
1665 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1666 * That is, the instruction that is either a NOP or call to
1667 * the function tracer. It checks the ftrace internal tables to
1668 * determine if the address belongs or not.
1670 unsigned long ftrace_location(unsigned long ip)
1672 return ftrace_location_range(ip, ip);
1676 * ftrace_text_reserved - return true if range contains an ftrace location
1677 * @start: start of range to search
1678 * @end: end of range to search (inclusive). @end points to the last byte to check.
1680 * Returns 1 if @start and @end contains a ftrace location.
1681 * That is, the instruction that is either a NOP or call to
1682 * the function tracer. It checks the ftrace internal tables to
1683 * determine if the address belongs or not.
1685 int ftrace_text_reserved(const void *start, const void *end)
1689 ret = ftrace_location_range((unsigned long)start,
1690 (unsigned long)end);
1695 /* Test if ops registered to this rec needs regs */
1696 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1698 struct ftrace_ops *ops;
1699 bool keep_regs = false;
1701 for (ops = ftrace_ops_list;
1702 ops != &ftrace_list_end; ops = ops->next) {
1703 /* pass rec in as regs to have non-NULL val */
1704 if (ftrace_ops_test(ops, rec->ip, rec)) {
1705 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1715 static struct ftrace_ops *
1716 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1717 static struct ftrace_ops *
1718 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1719 static struct ftrace_ops *
1720 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1722 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1726 struct ftrace_hash *hash;
1727 struct ftrace_hash *other_hash;
1728 struct ftrace_page *pg;
1729 struct dyn_ftrace *rec;
1730 bool update = false;
1734 /* Only update if the ops has been registered */
1735 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1739 * In the filter_hash case:
1740 * If the count is zero, we update all records.
1741 * Otherwise we just update the items in the hash.
1743 * In the notrace_hash case:
1744 * We enable the update in the hash.
1745 * As disabling notrace means enabling the tracing,
1746 * and enabling notrace means disabling, the inc variable
1750 hash = ops->func_hash->filter_hash;
1751 other_hash = ops->func_hash->notrace_hash;
1752 if (ftrace_hash_empty(hash))
1756 hash = ops->func_hash->notrace_hash;
1757 other_hash = ops->func_hash->filter_hash;
1759 * If the notrace hash has no items,
1760 * then there's nothing to do.
1762 if (ftrace_hash_empty(hash))
1766 do_for_each_ftrace_rec(pg, rec) {
1767 int in_other_hash = 0;
1771 if (rec->flags & FTRACE_FL_DISABLED)
1776 * Only the filter_hash affects all records.
1777 * Update if the record is not in the notrace hash.
1779 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1782 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1783 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1786 * If filter_hash is set, we want to match all functions
1787 * that are in the hash but not in the other hash.
1789 * If filter_hash is not set, then we are decrementing.
1790 * That means we match anything that is in the hash
1791 * and also in the other_hash. That is, we need to turn
1792 * off functions in the other hash because they are disabled
1795 if (filter_hash && in_hash && !in_other_hash)
1797 else if (!filter_hash && in_hash &&
1798 (in_other_hash || ftrace_hash_empty(other_hash)))
1806 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1810 * If there's only a single callback registered to a
1811 * function, and the ops has a trampoline registered
1812 * for it, then we can call it directly.
1814 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1815 rec->flags |= FTRACE_FL_TRAMP;
1818 * If we are adding another function callback
1819 * to this function, and the previous had a
1820 * custom trampoline in use, then we need to go
1821 * back to the default trampoline.
1823 rec->flags &= ~FTRACE_FL_TRAMP;
1826 * If any ops wants regs saved for this function
1827 * then all ops will get saved regs.
1829 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1830 rec->flags |= FTRACE_FL_REGS;
1832 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1837 * If the rec had REGS enabled and the ops that is
1838 * being removed had REGS set, then see if there is
1839 * still any ops for this record that wants regs.
1840 * If not, we can stop recording them.
1842 if (ftrace_rec_count(rec) > 0 &&
1843 rec->flags & FTRACE_FL_REGS &&
1844 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1845 if (!test_rec_ops_needs_regs(rec))
1846 rec->flags &= ~FTRACE_FL_REGS;
1850 * The TRAMP needs to be set only if rec count
1851 * is decremented to one, and the ops that is
1852 * left has a trampoline. As TRAMP can only be
1853 * enabled if there is only a single ops attached
1856 if (ftrace_rec_count(rec) == 1 &&
1857 ftrace_find_tramp_ops_any_other(rec, ops))
1858 rec->flags |= FTRACE_FL_TRAMP;
1860 rec->flags &= ~FTRACE_FL_TRAMP;
1863 * flags will be cleared in ftrace_check_record()
1864 * if rec count is zero.
1869 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1870 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1872 /* Shortcut, if we handled all records, we are done. */
1873 if (!all && count == hash->count)
1875 } while_for_each_ftrace_rec();
1880 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1883 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1886 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1889 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1892 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1893 int filter_hash, int inc)
1895 struct ftrace_ops *op;
1897 __ftrace_hash_rec_update(ops, filter_hash, inc);
1899 if (ops->func_hash != &global_ops.local_hash)
1903 * If the ops shares the global_ops hash, then we need to update
1904 * all ops that are enabled and use this hash.
1906 do_for_each_ftrace_op(op, ftrace_ops_list) {
1910 if (op->func_hash == &global_ops.local_hash)
1911 __ftrace_hash_rec_update(op, filter_hash, inc);
1912 } while_for_each_ftrace_op(op);
1915 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1918 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1921 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1924 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1928 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1929 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1930 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1931 * Note that old_hash and new_hash has below meanings
1932 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1933 * - If the hash is EMPTY_HASH, it hits nothing
1934 * - Anything else hits the recs which match the hash entries.
1936 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1937 struct ftrace_hash *old_hash,
1938 struct ftrace_hash *new_hash)
1940 struct ftrace_page *pg;
1941 struct dyn_ftrace *rec, *end = NULL;
1944 /* Only update if the ops has been registered */
1945 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1948 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1952 * Since the IPMODIFY is a very address sensitive action, we do not
1953 * allow ftrace_ops to set all functions to new hash.
1955 if (!new_hash || !old_hash)
1958 /* Update rec->flags */
1959 do_for_each_ftrace_rec(pg, rec) {
1961 if (rec->flags & FTRACE_FL_DISABLED)
1964 /* We need to update only differences of filter_hash */
1965 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1966 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1967 if (in_old == in_new)
1971 /* New entries must ensure no others are using it */
1972 if (rec->flags & FTRACE_FL_IPMODIFY)
1974 rec->flags |= FTRACE_FL_IPMODIFY;
1975 } else /* Removed entry */
1976 rec->flags &= ~FTRACE_FL_IPMODIFY;
1977 } while_for_each_ftrace_rec();
1984 /* Roll back what we did above */
1985 do_for_each_ftrace_rec(pg, rec) {
1987 if (rec->flags & FTRACE_FL_DISABLED)
1993 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1994 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1995 if (in_old == in_new)
1999 rec->flags &= ~FTRACE_FL_IPMODIFY;
2001 rec->flags |= FTRACE_FL_IPMODIFY;
2002 } while_for_each_ftrace_rec();
2008 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2010 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2012 if (ftrace_hash_empty(hash))
2015 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2018 /* Disabling always succeeds */
2019 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2021 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2023 if (ftrace_hash_empty(hash))
2026 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2029 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2030 struct ftrace_hash *new_hash)
2032 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2034 if (ftrace_hash_empty(old_hash))
2037 if (ftrace_hash_empty(new_hash))
2040 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2043 static void print_ip_ins(const char *fmt, const unsigned char *p)
2045 char ins[MCOUNT_INSN_SIZE];
2048 if (probe_kernel_read(ins, p, MCOUNT_INSN_SIZE)) {
2049 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2053 printk(KERN_CONT "%s", fmt);
2055 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
2056 printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
2059 enum ftrace_bug_type ftrace_bug_type;
2060 const void *ftrace_expected;
2062 static void print_bug_type(void)
2064 switch (ftrace_bug_type) {
2065 case FTRACE_BUG_UNKNOWN:
2067 case FTRACE_BUG_INIT:
2068 pr_info("Initializing ftrace call sites\n");
2070 case FTRACE_BUG_NOP:
2071 pr_info("Setting ftrace call site to NOP\n");
2073 case FTRACE_BUG_CALL:
2074 pr_info("Setting ftrace call site to call ftrace function\n");
2076 case FTRACE_BUG_UPDATE:
2077 pr_info("Updating ftrace call site to call a different ftrace function\n");
2083 * ftrace_bug - report and shutdown function tracer
2084 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2085 * @rec: The record that failed
2087 * The arch code that enables or disables the function tracing
2088 * can call ftrace_bug() when it has detected a problem in
2089 * modifying the code. @failed should be one of either:
2090 * EFAULT - if the problem happens on reading the @ip address
2091 * EINVAL - if what is read at @ip is not what was expected
2092 * EPERM - if the problem happens on writting to the @ip address
2094 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2096 unsigned long ip = rec ? rec->ip : 0;
2100 FTRACE_WARN_ON_ONCE(1);
2101 pr_info("ftrace faulted on modifying ");
2105 FTRACE_WARN_ON_ONCE(1);
2106 pr_info("ftrace failed to modify ");
2108 print_ip_ins(" actual: ", (unsigned char *)ip);
2110 if (ftrace_expected) {
2111 print_ip_ins(" expected: ", ftrace_expected);
2116 FTRACE_WARN_ON_ONCE(1);
2117 pr_info("ftrace faulted on writing ");
2121 FTRACE_WARN_ON_ONCE(1);
2122 pr_info("ftrace faulted on unknown error ");
2127 struct ftrace_ops *ops = NULL;
2129 pr_info("ftrace record flags: %lx\n", rec->flags);
2130 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2131 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2132 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2133 ops = ftrace_find_tramp_ops_any(rec);
2136 pr_cont("\ttramp: %pS (%pS)",
2137 (void *)ops->trampoline,
2139 ops = ftrace_find_tramp_ops_next(rec, ops);
2142 pr_cont("\ttramp: ERROR!");
2145 ip = ftrace_get_addr_curr(rec);
2146 pr_cont("\n expected tramp: %lx\n", ip);
2150 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2152 unsigned long flag = 0UL;
2154 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2156 if (rec->flags & FTRACE_FL_DISABLED)
2157 return FTRACE_UPDATE_IGNORE;
2160 * If we are updating calls:
2162 * If the record has a ref count, then we need to enable it
2163 * because someone is using it.
2165 * Otherwise we make sure its disabled.
2167 * If we are disabling calls, then disable all records that
2170 if (enable && ftrace_rec_count(rec))
2171 flag = FTRACE_FL_ENABLED;
2174 * If enabling and the REGS flag does not match the REGS_EN, or
2175 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2176 * this record. Set flags to fail the compare against ENABLED.
2179 if (!(rec->flags & FTRACE_FL_REGS) !=
2180 !(rec->flags & FTRACE_FL_REGS_EN))
2181 flag |= FTRACE_FL_REGS;
2183 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2184 !(rec->flags & FTRACE_FL_TRAMP_EN))
2185 flag |= FTRACE_FL_TRAMP;
2188 /* If the state of this record hasn't changed, then do nothing */
2189 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2190 return FTRACE_UPDATE_IGNORE;
2193 /* Save off if rec is being enabled (for return value) */
2194 flag ^= rec->flags & FTRACE_FL_ENABLED;
2197 rec->flags |= FTRACE_FL_ENABLED;
2198 if (flag & FTRACE_FL_REGS) {
2199 if (rec->flags & FTRACE_FL_REGS)
2200 rec->flags |= FTRACE_FL_REGS_EN;
2202 rec->flags &= ~FTRACE_FL_REGS_EN;
2204 if (flag & FTRACE_FL_TRAMP) {
2205 if (rec->flags & FTRACE_FL_TRAMP)
2206 rec->flags |= FTRACE_FL_TRAMP_EN;
2208 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2213 * If this record is being updated from a nop, then
2214 * return UPDATE_MAKE_CALL.
2216 * return UPDATE_MODIFY_CALL to tell the caller to convert
2217 * from the save regs, to a non-save regs function or
2218 * vice versa, or from a trampoline call.
2220 if (flag & FTRACE_FL_ENABLED) {
2221 ftrace_bug_type = FTRACE_BUG_CALL;
2222 return FTRACE_UPDATE_MAKE_CALL;
2225 ftrace_bug_type = FTRACE_BUG_UPDATE;
2226 return FTRACE_UPDATE_MODIFY_CALL;
2230 /* If there's no more users, clear all flags */
2231 if (!ftrace_rec_count(rec))
2235 * Just disable the record, but keep the ops TRAMP
2236 * and REGS states. The _EN flags must be disabled though.
2238 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2242 ftrace_bug_type = FTRACE_BUG_NOP;
2243 return FTRACE_UPDATE_MAKE_NOP;
2247 * ftrace_update_record, set a record that now is tracing or not
2248 * @rec: the record to update
2249 * @enable: set to 1 if the record is tracing, zero to force disable
2251 * The records that represent all functions that can be traced need
2252 * to be updated when tracing has been enabled.
2254 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2256 return ftrace_check_record(rec, enable, 1);
2260 * ftrace_test_record, check if the record has been enabled or not
2261 * @rec: the record to test
2262 * @enable: set to 1 to check if enabled, 0 if it is disabled
2264 * The arch code may need to test if a record is already set to
2265 * tracing to determine how to modify the function code that it
2268 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2270 return ftrace_check_record(rec, enable, 0);
2273 static struct ftrace_ops *
2274 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2276 struct ftrace_ops *op;
2277 unsigned long ip = rec->ip;
2279 do_for_each_ftrace_op(op, ftrace_ops_list) {
2281 if (!op->trampoline)
2284 if (hash_contains_ip(ip, op->func_hash))
2286 } while_for_each_ftrace_op(op);
2291 static struct ftrace_ops *
2292 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2294 struct ftrace_ops *op;
2295 unsigned long ip = rec->ip;
2297 do_for_each_ftrace_op(op, ftrace_ops_list) {
2299 if (op == op_exclude || !op->trampoline)
2302 if (hash_contains_ip(ip, op->func_hash))
2304 } while_for_each_ftrace_op(op);
2309 static struct ftrace_ops *
2310 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2311 struct ftrace_ops *op)
2313 unsigned long ip = rec->ip;
2315 while_for_each_ftrace_op(op) {
2317 if (!op->trampoline)
2320 if (hash_contains_ip(ip, op->func_hash))
2327 static struct ftrace_ops *
2328 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2330 struct ftrace_ops *op;
2331 unsigned long ip = rec->ip;
2334 * Need to check removed ops first.
2335 * If they are being removed, and this rec has a tramp,
2336 * and this rec is in the ops list, then it would be the
2337 * one with the tramp.
2340 if (hash_contains_ip(ip, &removed_ops->old_hash))
2345 * Need to find the current trampoline for a rec.
2346 * Now, a trampoline is only attached to a rec if there
2347 * was a single 'ops' attached to it. But this can be called
2348 * when we are adding another op to the rec or removing the
2349 * current one. Thus, if the op is being added, we can
2350 * ignore it because it hasn't attached itself to the rec
2353 * If an ops is being modified (hooking to different functions)
2354 * then we don't care about the new functions that are being
2355 * added, just the old ones (that are probably being removed).
2357 * If we are adding an ops to a function that already is using
2358 * a trampoline, it needs to be removed (trampolines are only
2359 * for single ops connected), then an ops that is not being
2360 * modified also needs to be checked.
2362 do_for_each_ftrace_op(op, ftrace_ops_list) {
2364 if (!op->trampoline)
2368 * If the ops is being added, it hasn't gotten to
2369 * the point to be removed from this tree yet.
2371 if (op->flags & FTRACE_OPS_FL_ADDING)
2376 * If the ops is being modified and is in the old
2377 * hash, then it is probably being removed from this
2380 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2381 hash_contains_ip(ip, &op->old_hash))
2384 * If the ops is not being added or modified, and it's
2385 * in its normal filter hash, then this must be the one
2388 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2389 hash_contains_ip(ip, op->func_hash))
2392 } while_for_each_ftrace_op(op);
2397 static struct ftrace_ops *
2398 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2400 struct ftrace_ops *op;
2401 unsigned long ip = rec->ip;
2403 do_for_each_ftrace_op(op, ftrace_ops_list) {
2404 /* pass rec in as regs to have non-NULL val */
2405 if (hash_contains_ip(ip, op->func_hash))
2407 } while_for_each_ftrace_op(op);
2413 * ftrace_get_addr_new - Get the call address to set to
2414 * @rec: The ftrace record descriptor
2416 * If the record has the FTRACE_FL_REGS set, that means that it
2417 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2418 * is not not set, then it wants to convert to the normal callback.
2420 * Returns the address of the trampoline to set to
2422 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2424 struct ftrace_ops *ops;
2426 /* Trampolines take precedence over regs */
2427 if (rec->flags & FTRACE_FL_TRAMP) {
2428 ops = ftrace_find_tramp_ops_new(rec);
2429 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2430 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2431 (void *)rec->ip, (void *)rec->ip, rec->flags);
2432 /* Ftrace is shutting down, return anything */
2433 return (unsigned long)FTRACE_ADDR;
2435 return ops->trampoline;
2438 if (rec->flags & FTRACE_FL_REGS)
2439 return (unsigned long)FTRACE_REGS_ADDR;
2441 return (unsigned long)FTRACE_ADDR;
2445 * ftrace_get_addr_curr - Get the call address that is already there
2446 * @rec: The ftrace record descriptor
2448 * The FTRACE_FL_REGS_EN is set when the record already points to
2449 * a function that saves all the regs. Basically the '_EN' version
2450 * represents the current state of the function.
2452 * Returns the address of the trampoline that is currently being called
2454 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2456 struct ftrace_ops *ops;
2458 /* Trampolines take precedence over regs */
2459 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2460 ops = ftrace_find_tramp_ops_curr(rec);
2461 if (FTRACE_WARN_ON(!ops)) {
2462 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2463 (void *)rec->ip, (void *)rec->ip);
2464 /* Ftrace is shutting down, return anything */
2465 return (unsigned long)FTRACE_ADDR;
2467 return ops->trampoline;
2470 if (rec->flags & FTRACE_FL_REGS_EN)
2471 return (unsigned long)FTRACE_REGS_ADDR;
2473 return (unsigned long)FTRACE_ADDR;
2477 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2479 unsigned long ftrace_old_addr;
2480 unsigned long ftrace_addr;
2483 ftrace_addr = ftrace_get_addr_new(rec);
2485 /* This needs to be done before we call ftrace_update_record */
2486 ftrace_old_addr = ftrace_get_addr_curr(rec);
2488 ret = ftrace_update_record(rec, enable);
2490 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2493 case FTRACE_UPDATE_IGNORE:
2496 case FTRACE_UPDATE_MAKE_CALL:
2497 ftrace_bug_type = FTRACE_BUG_CALL;
2498 return ftrace_make_call(rec, ftrace_addr);
2500 case FTRACE_UPDATE_MAKE_NOP:
2501 ftrace_bug_type = FTRACE_BUG_NOP;
2502 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2504 case FTRACE_UPDATE_MODIFY_CALL:
2505 ftrace_bug_type = FTRACE_BUG_UPDATE;
2506 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2509 return -1; /* unknow ftrace bug */
2512 void __weak ftrace_replace_code(int enable)
2514 struct dyn_ftrace *rec;
2515 struct ftrace_page *pg;
2518 if (unlikely(ftrace_disabled))
2521 do_for_each_ftrace_rec(pg, rec) {
2523 if (rec->flags & FTRACE_FL_DISABLED)
2526 failed = __ftrace_replace_code(rec, enable);
2528 ftrace_bug(failed, rec);
2529 /* Stop processing */
2532 } while_for_each_ftrace_rec();
2535 struct ftrace_rec_iter {
2536 struct ftrace_page *pg;
2541 * ftrace_rec_iter_start, start up iterating over traced functions
2543 * Returns an iterator handle that is used to iterate over all
2544 * the records that represent address locations where functions
2547 * May return NULL if no records are available.
2549 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2552 * We only use a single iterator.
2553 * Protected by the ftrace_lock mutex.
2555 static struct ftrace_rec_iter ftrace_rec_iter;
2556 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2558 iter->pg = ftrace_pages_start;
2561 /* Could have empty pages */
2562 while (iter->pg && !iter->pg->index)
2563 iter->pg = iter->pg->next;
2572 * ftrace_rec_iter_next, get the next record to process.
2573 * @iter: The handle to the iterator.
2575 * Returns the next iterator after the given iterator @iter.
2577 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2581 if (iter->index >= iter->pg->index) {
2582 iter->pg = iter->pg->next;
2585 /* Could have empty pages */
2586 while (iter->pg && !iter->pg->index)
2587 iter->pg = iter->pg->next;
2597 * ftrace_rec_iter_record, get the record at the iterator location
2598 * @iter: The current iterator location
2600 * Returns the record that the current @iter is at.
2602 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2604 return &iter->pg->records[iter->index];
2608 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2612 if (unlikely(ftrace_disabled))
2615 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2617 ftrace_bug_type = FTRACE_BUG_INIT;
2618 ftrace_bug(ret, rec);
2625 * archs can override this function if they must do something
2626 * before the modifying code is performed.
2628 int __weak ftrace_arch_code_modify_prepare(void)
2634 * archs can override this function if they must do something
2635 * after the modifying code is performed.
2637 int __weak ftrace_arch_code_modify_post_process(void)
2642 void ftrace_modify_all_code(int command)
2644 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2648 * If the ftrace_caller calls a ftrace_ops func directly,
2649 * we need to make sure that it only traces functions it
2650 * expects to trace. When doing the switch of functions,
2651 * we need to update to the ftrace_ops_list_func first
2652 * before the transition between old and new calls are set,
2653 * as the ftrace_ops_list_func will check the ops hashes
2654 * to make sure the ops are having the right functions
2658 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2659 if (FTRACE_WARN_ON(err))
2663 if (command & FTRACE_UPDATE_CALLS)
2664 ftrace_replace_code(1);
2665 else if (command & FTRACE_DISABLE_CALLS)
2666 ftrace_replace_code(0);
2668 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2669 function_trace_op = set_function_trace_op;
2671 /* If irqs are disabled, we are in stop machine */
2672 if (!irqs_disabled())
2673 smp_call_function(ftrace_sync_ipi, NULL, 1);
2674 err = ftrace_update_ftrace_func(ftrace_trace_function);
2675 if (FTRACE_WARN_ON(err))
2679 if (command & FTRACE_START_FUNC_RET)
2680 err = ftrace_enable_ftrace_graph_caller();
2681 else if (command & FTRACE_STOP_FUNC_RET)
2682 err = ftrace_disable_ftrace_graph_caller();
2683 FTRACE_WARN_ON(err);
2686 static int __ftrace_modify_code(void *data)
2688 int *command = data;
2690 ftrace_modify_all_code(*command);
2696 * ftrace_run_stop_machine, go back to the stop machine method
2697 * @command: The command to tell ftrace what to do
2699 * If an arch needs to fall back to the stop machine method, the
2700 * it can call this function.
2702 void ftrace_run_stop_machine(int command)
2704 stop_machine(__ftrace_modify_code, &command, NULL);
2708 * arch_ftrace_update_code, modify the code to trace or not trace
2709 * @command: The command that needs to be done
2711 * Archs can override this function if it does not need to
2712 * run stop_machine() to modify code.
2714 void __weak arch_ftrace_update_code(int command)
2716 ftrace_run_stop_machine(command);
2719 static void ftrace_run_update_code(int command)
2723 ret = ftrace_arch_code_modify_prepare();
2724 FTRACE_WARN_ON(ret);
2729 * By default we use stop_machine() to modify the code.
2730 * But archs can do what ever they want as long as it
2731 * is safe. The stop_machine() is the safest, but also
2732 * produces the most overhead.
2734 arch_ftrace_update_code(command);
2736 ret = ftrace_arch_code_modify_post_process();
2737 FTRACE_WARN_ON(ret);
2740 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2741 struct ftrace_ops_hash *old_hash)
2743 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2744 ops->old_hash.filter_hash = old_hash->filter_hash;
2745 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2746 ftrace_run_update_code(command);
2747 ops->old_hash.filter_hash = NULL;
2748 ops->old_hash.notrace_hash = NULL;
2749 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2752 static ftrace_func_t saved_ftrace_func;
2753 static int ftrace_start_up;
2755 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2759 static void per_cpu_ops_free(struct ftrace_ops *ops)
2761 free_percpu(ops->disabled);
2764 static void ftrace_startup_enable(int command)
2766 if (saved_ftrace_func != ftrace_trace_function) {
2767 saved_ftrace_func = ftrace_trace_function;
2768 command |= FTRACE_UPDATE_TRACE_FUNC;
2771 if (!command || !ftrace_enabled)
2774 ftrace_run_update_code(command);
2777 static void ftrace_startup_all(int command)
2779 update_all_ops = true;
2780 ftrace_startup_enable(command);
2781 update_all_ops = false;
2784 static int ftrace_startup(struct ftrace_ops *ops, int command)
2788 if (unlikely(ftrace_disabled))
2791 ret = __register_ftrace_function(ops);
2798 * Note that ftrace probes uses this to start up
2799 * and modify functions it will probe. But we still
2800 * set the ADDING flag for modification, as probes
2801 * do not have trampolines. If they add them in the
2802 * future, then the probes will need to distinguish
2803 * between adding and updating probes.
2805 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2807 ret = ftrace_hash_ipmodify_enable(ops);
2809 /* Rollback registration process */
2810 __unregister_ftrace_function(ops);
2812 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2816 if (ftrace_hash_rec_enable(ops, 1))
2817 command |= FTRACE_UPDATE_CALLS;
2819 ftrace_startup_enable(command);
2821 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2826 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2830 if (unlikely(ftrace_disabled))
2833 ret = __unregister_ftrace_function(ops);
2839 * Just warn in case of unbalance, no need to kill ftrace, it's not
2840 * critical but the ftrace_call callers may be never nopped again after
2841 * further ftrace uses.
2843 WARN_ON_ONCE(ftrace_start_up < 0);
2845 /* Disabling ipmodify never fails */
2846 ftrace_hash_ipmodify_disable(ops);
2848 if (ftrace_hash_rec_disable(ops, 1))
2849 command |= FTRACE_UPDATE_CALLS;
2851 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2853 if (saved_ftrace_func != ftrace_trace_function) {
2854 saved_ftrace_func = ftrace_trace_function;
2855 command |= FTRACE_UPDATE_TRACE_FUNC;
2858 if (!command || !ftrace_enabled) {
2860 * If these are dynamic or per_cpu ops, they still
2861 * need their data freed. Since, function tracing is
2862 * not currently active, we can just free them
2863 * without synchronizing all CPUs.
2865 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU))
2872 * If the ops uses a trampoline, then it needs to be
2873 * tested first on update.
2875 ops->flags |= FTRACE_OPS_FL_REMOVING;
2878 /* The trampoline logic checks the old hashes */
2879 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2880 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2882 ftrace_run_update_code(command);
2885 * If there's no more ops registered with ftrace, run a
2886 * sanity check to make sure all rec flags are cleared.
2888 if (rcu_dereference_protected(ftrace_ops_list,
2889 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2890 struct ftrace_page *pg;
2891 struct dyn_ftrace *rec;
2893 do_for_each_ftrace_rec(pg, rec) {
2894 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2895 pr_warn(" %pS flags:%lx\n",
2896 (void *)rec->ip, rec->flags);
2897 } while_for_each_ftrace_rec();
2900 ops->old_hash.filter_hash = NULL;
2901 ops->old_hash.notrace_hash = NULL;
2904 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2907 * Dynamic ops may be freed, we must make sure that all
2908 * callers are done before leaving this function.
2909 * The same goes for freeing the per_cpu data of the per_cpu
2912 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2914 * We need to do a hard force of sched synchronization.
2915 * This is because we use preempt_disable() to do RCU, but
2916 * the function tracers can be called where RCU is not watching
2917 * (like before user_exit()). We can not rely on the RCU
2918 * infrastructure to do the synchronization, thus we must do it
2921 schedule_on_each_cpu(ftrace_sync);
2924 * When the kernel is preeptive, tasks can be preempted
2925 * while on a ftrace trampoline. Just scheduling a task on
2926 * a CPU is not good enough to flush them. Calling
2927 * synchornize_rcu_tasks() will wait for those tasks to
2928 * execute and either schedule voluntarily or enter user space.
2930 if (IS_ENABLED(CONFIG_PREEMPT))
2931 synchronize_rcu_tasks();
2934 arch_ftrace_trampoline_free(ops);
2936 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2937 per_cpu_ops_free(ops);
2943 static void ftrace_startup_sysctl(void)
2947 if (unlikely(ftrace_disabled))
2950 /* Force update next time */
2951 saved_ftrace_func = NULL;
2952 /* ftrace_start_up is true if we want ftrace running */
2953 if (ftrace_start_up) {
2954 command = FTRACE_UPDATE_CALLS;
2955 if (ftrace_graph_active)
2956 command |= FTRACE_START_FUNC_RET;
2957 ftrace_startup_enable(command);
2961 static void ftrace_shutdown_sysctl(void)
2965 if (unlikely(ftrace_disabled))
2968 /* ftrace_start_up is true if ftrace is running */
2969 if (ftrace_start_up) {
2970 command = FTRACE_DISABLE_CALLS;
2971 if (ftrace_graph_active)
2972 command |= FTRACE_STOP_FUNC_RET;
2973 ftrace_run_update_code(command);
2977 static u64 ftrace_update_time;
2978 unsigned long ftrace_update_tot_cnt;
2980 static inline int ops_traces_mod(struct ftrace_ops *ops)
2983 * Filter_hash being empty will default to trace module.
2984 * But notrace hash requires a test of individual module functions.
2986 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2987 ftrace_hash_empty(ops->func_hash->notrace_hash);
2991 * Check if the current ops references the record.
2993 * If the ops traces all functions, then it was already accounted for.
2994 * If the ops does not trace the current record function, skip it.
2995 * If the ops ignores the function via notrace filter, skip it.
2998 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3000 /* If ops isn't enabled, ignore it */
3001 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
3004 /* If ops traces all then it includes this function */
3005 if (ops_traces_mod(ops))
3008 /* The function must be in the filter */
3009 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
3010 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
3013 /* If in notrace hash, we ignore it too */
3014 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
3020 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3022 struct ftrace_page *pg;
3023 struct dyn_ftrace *p;
3025 unsigned long update_cnt = 0;
3026 unsigned long rec_flags = 0;
3029 start = ftrace_now(raw_smp_processor_id());
3032 * When a module is loaded, this function is called to convert
3033 * the calls to mcount in its text to nops, and also to create
3034 * an entry in the ftrace data. Now, if ftrace is activated
3035 * after this call, but before the module sets its text to
3036 * read-only, the modification of enabling ftrace can fail if
3037 * the read-only is done while ftrace is converting the calls.
3038 * To prevent this, the module's records are set as disabled
3039 * and will be enabled after the call to set the module's text
3043 rec_flags |= FTRACE_FL_DISABLED;
3045 for (pg = new_pgs; pg; pg = pg->next) {
3047 for (i = 0; i < pg->index; i++) {
3049 /* If something went wrong, bail without enabling anything */
3050 if (unlikely(ftrace_disabled))
3053 p = &pg->records[i];
3054 p->flags = rec_flags;
3057 * Do the initial record conversion from mcount jump
3058 * to the NOP instructions.
3060 if (!ftrace_code_disable(mod, p))
3067 stop = ftrace_now(raw_smp_processor_id());
3068 ftrace_update_time = stop - start;
3069 ftrace_update_tot_cnt += update_cnt;
3074 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3079 if (WARN_ON(!count))
3082 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3085 * We want to fill as much as possible. No more than a page
3088 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3092 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3095 /* if we can't allocate this size, try something smaller */
3102 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3111 static struct ftrace_page *
3112 ftrace_allocate_pages(unsigned long num_to_init)
3114 struct ftrace_page *start_pg;
3115 struct ftrace_page *pg;
3122 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3127 * Try to allocate as much as possible in one continues
3128 * location that fills in all of the space. We want to
3129 * waste as little space as possible.
3132 cnt = ftrace_allocate_records(pg, num_to_init);
3140 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3152 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3153 free_pages((unsigned long)pg->records, order);
3154 start_pg = pg->next;
3158 pr_info("ftrace: FAILED to allocate memory for functions\n");
3162 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3164 struct ftrace_iterator {
3168 struct ftrace_page *pg;
3169 struct dyn_ftrace *func;
3170 struct ftrace_func_probe *probe;
3171 struct ftrace_func_entry *probe_entry;
3172 struct trace_parser parser;
3173 struct ftrace_hash *hash;
3174 struct ftrace_ops *ops;
3175 struct trace_array *tr;
3176 struct list_head *mod_list;
3183 t_probe_next(struct seq_file *m, loff_t *pos)
3185 struct ftrace_iterator *iter = m->private;
3186 struct trace_array *tr = iter->ops->private;
3187 struct list_head *func_probes;
3188 struct ftrace_hash *hash;
3189 struct list_head *next;
3190 struct hlist_node *hnd = NULL;
3191 struct hlist_head *hhd;
3200 func_probes = &tr->func_probes;
3201 if (list_empty(func_probes))
3205 next = func_probes->next;
3206 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3209 if (iter->probe_entry)
3210 hnd = &iter->probe_entry->hlist;
3212 hash = iter->probe->ops.func_hash->filter_hash;
3215 * A probe being registered may temporarily have an empty hash
3216 * and it's at the end of the func_probes list.
3218 if (!hash || hash == EMPTY_HASH)
3221 size = 1 << hash->size_bits;
3224 if (iter->pidx >= size) {
3225 if (iter->probe->list.next == func_probes)
3227 next = iter->probe->list.next;
3228 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3229 hash = iter->probe->ops.func_hash->filter_hash;
3230 size = 1 << hash->size_bits;
3234 hhd = &hash->buckets[iter->pidx];
3236 if (hlist_empty(hhd)) {
3252 if (WARN_ON_ONCE(!hnd))
3255 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3260 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3262 struct ftrace_iterator *iter = m->private;
3266 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3269 if (iter->mod_pos > *pos)
3273 iter->probe_entry = NULL;
3275 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3276 p = t_probe_next(m, &l);
3283 /* Only set this if we have an item */
3284 iter->flags |= FTRACE_ITER_PROBE;
3290 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3292 struct ftrace_func_entry *probe_entry;
3293 struct ftrace_probe_ops *probe_ops;
3294 struct ftrace_func_probe *probe;
3296 probe = iter->probe;
3297 probe_entry = iter->probe_entry;
3299 if (WARN_ON_ONCE(!probe || !probe_entry))
3302 probe_ops = probe->probe_ops;
3304 if (probe_ops->print)
3305 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3307 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3308 (void *)probe_ops->func);
3314 t_mod_next(struct seq_file *m, loff_t *pos)
3316 struct ftrace_iterator *iter = m->private;
3317 struct trace_array *tr = iter->tr;
3322 iter->mod_list = iter->mod_list->next;
3324 if (iter->mod_list == &tr->mod_trace ||
3325 iter->mod_list == &tr->mod_notrace) {
3326 iter->flags &= ~FTRACE_ITER_MOD;
3330 iter->mod_pos = *pos;
3335 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3337 struct ftrace_iterator *iter = m->private;
3341 if (iter->func_pos > *pos)
3344 iter->mod_pos = iter->func_pos;
3346 /* probes are only available if tr is set */
3350 for (l = 0; l <= (*pos - iter->func_pos); ) {
3351 p = t_mod_next(m, &l);
3356 iter->flags &= ~FTRACE_ITER_MOD;
3357 return t_probe_start(m, pos);
3360 /* Only set this if we have an item */
3361 iter->flags |= FTRACE_ITER_MOD;
3367 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3369 struct ftrace_mod_load *ftrace_mod;
3370 struct trace_array *tr = iter->tr;
3372 if (WARN_ON_ONCE(!iter->mod_list) ||
3373 iter->mod_list == &tr->mod_trace ||
3374 iter->mod_list == &tr->mod_notrace)
3377 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3379 if (ftrace_mod->func)
3380 seq_printf(m, "%s", ftrace_mod->func);
3384 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3390 t_func_next(struct seq_file *m, loff_t *pos)
3392 struct ftrace_iterator *iter = m->private;
3393 struct dyn_ftrace *rec = NULL;
3398 if (iter->idx >= iter->pg->index) {
3399 if (iter->pg->next) {
3400 iter->pg = iter->pg->next;
3405 rec = &iter->pg->records[iter->idx++];
3406 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3407 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3409 ((iter->flags & FTRACE_ITER_ENABLED) &&
3410 !(rec->flags & FTRACE_FL_ENABLED))) {
3420 iter->pos = iter->func_pos = *pos;
3427 t_next(struct seq_file *m, void *v, loff_t *pos)
3429 struct ftrace_iterator *iter = m->private;
3430 loff_t l = *pos; /* t_probe_start() must use original pos */
3433 if (unlikely(ftrace_disabled))
3436 if (iter->flags & FTRACE_ITER_PROBE)
3437 return t_probe_next(m, pos);
3439 if (iter->flags & FTRACE_ITER_MOD)
3440 return t_mod_next(m, pos);
3442 if (iter->flags & FTRACE_ITER_PRINTALL) {
3443 /* next must increment pos, and t_probe_start does not */
3445 return t_mod_start(m, &l);
3448 ret = t_func_next(m, pos);
3451 return t_mod_start(m, &l);
3456 static void reset_iter_read(struct ftrace_iterator *iter)
3460 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3463 static void *t_start(struct seq_file *m, loff_t *pos)
3465 struct ftrace_iterator *iter = m->private;
3469 mutex_lock(&ftrace_lock);
3471 if (unlikely(ftrace_disabled))
3475 * If an lseek was done, then reset and start from beginning.
3477 if (*pos < iter->pos)
3478 reset_iter_read(iter);
3481 * For set_ftrace_filter reading, if we have the filter
3482 * off, we can short cut and just print out that all
3483 * functions are enabled.
3485 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3486 ftrace_hash_empty(iter->hash)) {
3487 iter->func_pos = 1; /* Account for the message */
3489 return t_mod_start(m, pos);
3490 iter->flags |= FTRACE_ITER_PRINTALL;
3491 /* reset in case of seek/pread */
3492 iter->flags &= ~FTRACE_ITER_PROBE;
3496 if (iter->flags & FTRACE_ITER_MOD)
3497 return t_mod_start(m, pos);
3500 * Unfortunately, we need to restart at ftrace_pages_start
3501 * every time we let go of the ftrace_mutex. This is because
3502 * those pointers can change without the lock.
3504 iter->pg = ftrace_pages_start;
3506 for (l = 0; l <= *pos; ) {
3507 p = t_func_next(m, &l);
3513 return t_mod_start(m, pos);
3518 static void t_stop(struct seq_file *m, void *p)
3520 mutex_unlock(&ftrace_lock);
3524 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3529 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3530 struct dyn_ftrace *rec)
3534 ptr = arch_ftrace_trampoline_func(ops, rec);
3536 seq_printf(m, " ->%pS", ptr);
3539 static int t_show(struct seq_file *m, void *v)
3541 struct ftrace_iterator *iter = m->private;
3542 struct dyn_ftrace *rec;
3544 if (iter->flags & FTRACE_ITER_PROBE)
3545 return t_probe_show(m, iter);
3547 if (iter->flags & FTRACE_ITER_MOD)
3548 return t_mod_show(m, iter);
3550 if (iter->flags & FTRACE_ITER_PRINTALL) {
3551 if (iter->flags & FTRACE_ITER_NOTRACE)
3552 seq_puts(m, "#### no functions disabled ####\n");
3554 seq_puts(m, "#### all functions enabled ####\n");
3563 seq_printf(m, "%ps", (void *)rec->ip);
3564 if (iter->flags & FTRACE_ITER_ENABLED) {
3565 struct ftrace_ops *ops;
3567 seq_printf(m, " (%ld)%s%s",
3568 ftrace_rec_count(rec),
3569 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3570 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3571 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3572 ops = ftrace_find_tramp_ops_any(rec);
3575 seq_printf(m, "\ttramp: %pS (%pS)",
3576 (void *)ops->trampoline,
3578 add_trampoline_func(m, ops, rec);
3579 ops = ftrace_find_tramp_ops_next(rec, ops);
3582 seq_puts(m, "\ttramp: ERROR!");
3584 add_trampoline_func(m, NULL, rec);
3593 static const struct seq_operations show_ftrace_seq_ops = {
3601 ftrace_avail_open(struct inode *inode, struct file *file)
3603 struct ftrace_iterator *iter;
3605 if (unlikely(ftrace_disabled))
3608 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3612 iter->pg = ftrace_pages_start;
3613 iter->ops = &global_ops;
3619 ftrace_enabled_open(struct inode *inode, struct file *file)
3621 struct ftrace_iterator *iter;
3623 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3627 iter->pg = ftrace_pages_start;
3628 iter->flags = FTRACE_ITER_ENABLED;
3629 iter->ops = &global_ops;
3635 * ftrace_regex_open - initialize function tracer filter files
3636 * @ops: The ftrace_ops that hold the hash filters
3637 * @flag: The type of filter to process
3638 * @inode: The inode, usually passed in to your open routine
3639 * @file: The file, usually passed in to your open routine
3641 * ftrace_regex_open() initializes the filter files for the
3642 * @ops. Depending on @flag it may process the filter hash or
3643 * the notrace hash of @ops. With this called from the open
3644 * routine, you can use ftrace_filter_write() for the write
3645 * routine if @flag has FTRACE_ITER_FILTER set, or
3646 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3647 * tracing_lseek() should be used as the lseek routine, and
3648 * release must call ftrace_regex_release().
3651 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3652 struct inode *inode, struct file *file)
3654 struct ftrace_iterator *iter;
3655 struct ftrace_hash *hash;
3656 struct list_head *mod_head;
3657 struct trace_array *tr = ops->private;
3660 ftrace_ops_init(ops);
3662 if (unlikely(ftrace_disabled))
3665 if (tr && trace_array_get(tr) < 0)
3668 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3672 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3679 mutex_lock(&ops->func_hash->regex_lock);
3681 if (flag & FTRACE_ITER_NOTRACE) {
3682 hash = ops->func_hash->notrace_hash;
3683 mod_head = tr ? &tr->mod_notrace : NULL;
3685 hash = ops->func_hash->filter_hash;
3686 mod_head = tr ? &tr->mod_trace : NULL;
3689 iter->mod_list = mod_head;
3691 if (file->f_mode & FMODE_WRITE) {
3692 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3694 if (file->f_flags & O_TRUNC) {
3695 iter->hash = alloc_ftrace_hash(size_bits);
3696 clear_ftrace_mod_list(mod_head);
3698 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3702 trace_parser_put(&iter->parser);
3710 if (file->f_mode & FMODE_READ) {
3711 iter->pg = ftrace_pages_start;
3713 ret = seq_open(file, &show_ftrace_seq_ops);
3715 struct seq_file *m = file->private_data;
3719 free_ftrace_hash(iter->hash);
3720 trace_parser_put(&iter->parser);
3723 file->private_data = iter;
3726 mutex_unlock(&ops->func_hash->regex_lock);
3732 trace_array_put(tr);
3739 ftrace_filter_open(struct inode *inode, struct file *file)
3741 struct ftrace_ops *ops = inode->i_private;
3743 return ftrace_regex_open(ops,
3744 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3749 ftrace_notrace_open(struct inode *inode, struct file *file)
3751 struct ftrace_ops *ops = inode->i_private;
3753 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3757 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3758 struct ftrace_glob {
3765 * If symbols in an architecture don't correspond exactly to the user-visible
3766 * name of what they represent, it is possible to define this function to
3767 * perform the necessary adjustments.
3769 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3774 static int ftrace_match(char *str, struct ftrace_glob *g)
3779 str = arch_ftrace_match_adjust(str, g->search);
3783 if (strcmp(str, g->search) == 0)
3786 case MATCH_FRONT_ONLY:
3787 if (strncmp(str, g->search, g->len) == 0)
3790 case MATCH_MIDDLE_ONLY:
3791 if (strstr(str, g->search))
3794 case MATCH_END_ONLY:
3796 if (slen >= g->len &&
3797 memcmp(str + slen - g->len, g->search, g->len) == 0)
3801 if (glob_match(g->search, str))
3810 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3812 struct ftrace_func_entry *entry;
3815 entry = ftrace_lookup_ip(hash, rec->ip);
3817 /* Do nothing if it doesn't exist */
3821 free_hash_entry(hash, entry);
3823 /* Do nothing if it exists */
3827 ret = add_hash_entry(hash, rec->ip);
3833 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3834 struct ftrace_glob *mod_g, int exclude_mod)
3836 char str[KSYM_SYMBOL_LEN];
3839 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3842 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3844 /* blank module name to match all modules */
3846 /* blank module globbing: modname xor exclude_mod */
3847 if (!exclude_mod != !modname)
3853 * exclude_mod is set to trace everything but the given
3854 * module. If it is set and the module matches, then
3855 * return 0. If it is not set, and the module doesn't match
3856 * also return 0. Otherwise, check the function to see if
3859 if (!mod_matches == !exclude_mod)
3862 /* blank search means to match all funcs in the mod */
3867 return ftrace_match(str, func_g);
3871 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3873 struct ftrace_page *pg;
3874 struct dyn_ftrace *rec;
3875 struct ftrace_glob func_g = { .type = MATCH_FULL };
3876 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3877 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3878 int exclude_mod = 0;
3881 int clear_filter = 0;
3884 func_g.type = filter_parse_regex(func, len, &func_g.search,
3886 func_g.len = strlen(func_g.search);
3890 mod_g.type = filter_parse_regex(mod, strlen(mod),
3891 &mod_g.search, &exclude_mod);
3892 mod_g.len = strlen(mod_g.search);
3895 mutex_lock(&ftrace_lock);
3897 if (unlikely(ftrace_disabled))
3900 do_for_each_ftrace_rec(pg, rec) {
3902 if (rec->flags & FTRACE_FL_DISABLED)
3905 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3906 ret = enter_record(hash, rec, clear_filter);
3913 } while_for_each_ftrace_rec();
3915 mutex_unlock(&ftrace_lock);
3921 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3923 return match_records(hash, buff, len, NULL);
3926 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3927 struct ftrace_ops_hash *old_hash)
3929 struct ftrace_ops *op;
3931 if (!ftrace_enabled)
3934 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3935 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3940 * If this is the shared global_ops filter, then we need to
3941 * check if there is another ops that shares it, is enabled.
3942 * If so, we still need to run the modify code.
3944 if (ops->func_hash != &global_ops.local_hash)
3947 do_for_each_ftrace_op(op, ftrace_ops_list) {
3948 if (op->func_hash == &global_ops.local_hash &&
3949 op->flags & FTRACE_OPS_FL_ENABLED) {
3950 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3951 /* Only need to do this once */
3954 } while_for_each_ftrace_op(op);
3957 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3958 struct ftrace_hash **orig_hash,
3959 struct ftrace_hash *hash,
3962 struct ftrace_ops_hash old_hash_ops;
3963 struct ftrace_hash *old_hash;
3966 old_hash = *orig_hash;
3967 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3968 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3969 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3971 ftrace_ops_update_code(ops, &old_hash_ops);
3972 free_ftrace_hash_rcu(old_hash);
3977 static bool module_exists(const char *module)
3979 /* All modules have the symbol __this_module */
3980 const char this_mod[] = "__this_module";
3981 const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1;
3982 char modname[modname_size + 1];
3986 n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod);
3988 if (n > modname_size)
3991 val = module_kallsyms_lookup_name(modname);
3995 static int cache_mod(struct trace_array *tr,
3996 const char *func, char *module, int enable)
3998 struct ftrace_mod_load *ftrace_mod, *n;
3999 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4002 mutex_lock(&ftrace_lock);
4004 /* We do not cache inverse filters */
4005 if (func[0] == '!') {
4009 /* Look to remove this hash */
4010 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4011 if (strcmp(ftrace_mod->module, module) != 0)
4014 /* no func matches all */
4015 if (strcmp(func, "*") == 0 ||
4016 (ftrace_mod->func &&
4017 strcmp(ftrace_mod->func, func) == 0)) {
4019 free_ftrace_mod(ftrace_mod);
4027 /* We only care about modules that have not been loaded yet */
4028 if (module_exists(module))
4031 /* Save this string off, and execute it when the module is loaded */
4032 ret = ftrace_add_mod(tr, func, module, enable);
4034 mutex_unlock(&ftrace_lock);
4040 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4041 int reset, int enable);
4043 #ifdef CONFIG_MODULES
4044 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4045 char *mod, bool enable)
4047 struct ftrace_mod_load *ftrace_mod, *n;
4048 struct ftrace_hash **orig_hash, *new_hash;
4049 LIST_HEAD(process_mods);
4053 mutex_lock(&ops->func_hash->regex_lock);
4056 orig_hash = &ops->func_hash->filter_hash;
4058 orig_hash = &ops->func_hash->notrace_hash;
4060 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4063 goto out; /* warn? */
4065 mutex_lock(&ftrace_lock);
4067 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4069 if (strcmp(ftrace_mod->module, mod) != 0)
4072 if (ftrace_mod->func)
4073 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4075 func = kstrdup("*", GFP_KERNEL);
4077 if (!func) /* warn? */
4080 list_del(&ftrace_mod->list);
4081 list_add(&ftrace_mod->list, &process_mods);
4083 /* Use the newly allocated func, as it may be "*" */
4084 kfree(ftrace_mod->func);
4085 ftrace_mod->func = func;
4088 mutex_unlock(&ftrace_lock);
4090 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4092 func = ftrace_mod->func;
4094 /* Grabs ftrace_lock, which is why we have this extra step */
4095 match_records(new_hash, func, strlen(func), mod);
4096 free_ftrace_mod(ftrace_mod);
4099 if (enable && list_empty(head))
4100 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4102 mutex_lock(&ftrace_lock);
4104 ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4106 mutex_unlock(&ftrace_lock);
4109 mutex_unlock(&ops->func_hash->regex_lock);
4111 free_ftrace_hash(new_hash);
4114 static void process_cached_mods(const char *mod_name)
4116 struct trace_array *tr;
4119 mod = kstrdup(mod_name, GFP_KERNEL);
4123 mutex_lock(&trace_types_lock);
4124 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4125 if (!list_empty(&tr->mod_trace))
4126 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4127 if (!list_empty(&tr->mod_notrace))
4128 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4130 mutex_unlock(&trace_types_lock);
4137 * We register the module command as a template to show others how
4138 * to register the a command as well.
4142 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4143 char *func_orig, char *cmd, char *module, int enable)
4148 /* match_records() modifies func, and we need the original */
4149 func = kstrdup(func_orig, GFP_KERNEL);
4154 * cmd == 'mod' because we only registered this func
4155 * for the 'mod' ftrace_func_command.
4156 * But if you register one func with multiple commands,
4157 * you can tell which command was used by the cmd
4160 ret = match_records(hash, func, strlen(func), module);
4164 return cache_mod(tr, func_orig, module, enable);
4170 static struct ftrace_func_command ftrace_mod_cmd = {
4172 .func = ftrace_mod_callback,
4175 static int __init ftrace_mod_cmd_init(void)
4177 return register_ftrace_command(&ftrace_mod_cmd);
4179 core_initcall(ftrace_mod_cmd_init);
4181 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4182 struct ftrace_ops *op, struct pt_regs *pt_regs)
4184 struct ftrace_probe_ops *probe_ops;
4185 struct ftrace_func_probe *probe;
4187 probe = container_of(op, struct ftrace_func_probe, ops);
4188 probe_ops = probe->probe_ops;
4191 * Disable preemption for these calls to prevent a RCU grace
4192 * period. This syncs the hash iteration and freeing of items
4193 * on the hash. rcu_read_lock is too dangerous here.
4195 preempt_disable_notrace();
4196 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4197 preempt_enable_notrace();
4200 struct ftrace_func_map {
4201 struct ftrace_func_entry entry;
4205 struct ftrace_func_mapper {
4206 struct ftrace_hash hash;
4210 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4212 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4214 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4216 struct ftrace_hash *hash;
4219 * The mapper is simply a ftrace_hash, but since the entries
4220 * in the hash are not ftrace_func_entry type, we define it
4221 * as a separate structure.
4223 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4224 return (struct ftrace_func_mapper *)hash;
4228 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4229 * @mapper: The mapper that has the ip maps
4230 * @ip: the instruction pointer to find the data for
4232 * Returns the data mapped to @ip if found otherwise NULL. The return
4233 * is actually the address of the mapper data pointer. The address is
4234 * returned for use cases where the data is no bigger than a long, and
4235 * the user can use the data pointer as its data instead of having to
4236 * allocate more memory for the reference.
4238 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4241 struct ftrace_func_entry *entry;
4242 struct ftrace_func_map *map;
4244 entry = ftrace_lookup_ip(&mapper->hash, ip);
4248 map = (struct ftrace_func_map *)entry;
4253 * ftrace_func_mapper_add_ip - Map some data to an ip
4254 * @mapper: The mapper that has the ip maps
4255 * @ip: The instruction pointer address to map @data to
4256 * @data: The data to map to @ip
4258 * Returns 0 on succes otherwise an error.
4260 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4261 unsigned long ip, void *data)
4263 struct ftrace_func_entry *entry;
4264 struct ftrace_func_map *map;
4266 entry = ftrace_lookup_ip(&mapper->hash, ip);
4270 map = kmalloc(sizeof(*map), GFP_KERNEL);
4277 __add_hash_entry(&mapper->hash, &map->entry);
4283 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4284 * @mapper: The mapper that has the ip maps
4285 * @ip: The instruction pointer address to remove the data from
4287 * Returns the data if it is found, otherwise NULL.
4288 * Note, if the data pointer is used as the data itself, (see
4289 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4290 * if the data pointer was set to zero.
4292 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4295 struct ftrace_func_entry *entry;
4296 struct ftrace_func_map *map;
4299 entry = ftrace_lookup_ip(&mapper->hash, ip);
4303 map = (struct ftrace_func_map *)entry;
4306 remove_hash_entry(&mapper->hash, entry);
4313 * free_ftrace_func_mapper - free a mapping of ips and data
4314 * @mapper: The mapper that has the ip maps
4315 * @free_func: A function to be called on each data item.
4317 * This is used to free the function mapper. The @free_func is optional
4318 * and can be used if the data needs to be freed as well.
4320 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4321 ftrace_mapper_func free_func)
4323 struct ftrace_func_entry *entry;
4324 struct ftrace_func_map *map;
4325 struct hlist_head *hhd;
4331 if (free_func && mapper->hash.count) {
4332 size = 1 << mapper->hash.size_bits;
4333 for (i = 0; i < size; i++) {
4334 hhd = &mapper->hash.buckets[i];
4335 hlist_for_each_entry(entry, hhd, hlist) {
4336 map = (struct ftrace_func_map *)entry;
4341 free_ftrace_hash(&mapper->hash);
4344 static void release_probe(struct ftrace_func_probe *probe)
4346 struct ftrace_probe_ops *probe_ops;
4348 mutex_lock(&ftrace_lock);
4350 WARN_ON(probe->ref <= 0);
4352 /* Subtract the ref that was used to protect this instance */
4356 probe_ops = probe->probe_ops;
4358 * Sending zero as ip tells probe_ops to free
4359 * the probe->data itself
4361 if (probe_ops->free)
4362 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4363 list_del(&probe->list);
4366 mutex_unlock(&ftrace_lock);
4369 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4372 * Add one ref to keep it from being freed when releasing the
4373 * ftrace_lock mutex.
4379 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4380 struct ftrace_probe_ops *probe_ops,
4383 struct ftrace_func_entry *entry;
4384 struct ftrace_func_probe *probe;
4385 struct ftrace_hash **orig_hash;
4386 struct ftrace_hash *old_hash;
4387 struct ftrace_hash *hash;
4396 /* We do not support '!' for function probes */
4397 if (WARN_ON(glob[0] == '!'))
4401 mutex_lock(&ftrace_lock);
4402 /* Check if the probe_ops is already registered */
4403 list_for_each_entry(probe, &tr->func_probes, list) {
4404 if (probe->probe_ops == probe_ops)
4407 if (&probe->list == &tr->func_probes) {
4408 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4410 mutex_unlock(&ftrace_lock);
4413 probe->probe_ops = probe_ops;
4414 probe->ops.func = function_trace_probe_call;
4416 ftrace_ops_init(&probe->ops);
4417 list_add(&probe->list, &tr->func_probes);
4420 acquire_probe_locked(probe);
4422 mutex_unlock(&ftrace_lock);
4425 * Note, there's a small window here that the func_hash->filter_hash
4426 * may be NULL or empty. Need to be carefule when reading the loop.
4428 mutex_lock(&probe->ops.func_hash->regex_lock);
4430 orig_hash = &probe->ops.func_hash->filter_hash;
4431 old_hash = *orig_hash;
4432 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4439 ret = ftrace_match_records(hash, glob, strlen(glob));
4441 /* Nothing found? */
4448 size = 1 << hash->size_bits;
4449 for (i = 0; i < size; i++) {
4450 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4451 if (ftrace_lookup_ip(old_hash, entry->ip))
4454 * The caller might want to do something special
4455 * for each function we find. We call the callback
4456 * to give the caller an opportunity to do so.
4458 if (probe_ops->init) {
4459 ret = probe_ops->init(probe_ops, tr,
4463 if (probe_ops->free && count)
4464 probe_ops->free(probe_ops, tr,
4474 mutex_lock(&ftrace_lock);
4477 /* Nothing was added? */
4482 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4487 /* One ref for each new function traced */
4488 probe->ref += count;
4490 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4491 ret = ftrace_startup(&probe->ops, 0);
4494 mutex_unlock(&ftrace_lock);
4499 mutex_unlock(&probe->ops.func_hash->regex_lock);
4500 free_ftrace_hash(hash);
4502 release_probe(probe);
4507 if (!probe_ops->free || !count)
4510 /* Failed to do the move, need to call the free functions */
4511 for (i = 0; i < size; i++) {
4512 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4513 if (ftrace_lookup_ip(old_hash, entry->ip))
4515 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4522 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4523 struct ftrace_probe_ops *probe_ops)
4525 struct ftrace_ops_hash old_hash_ops;
4526 struct ftrace_func_entry *entry;
4527 struct ftrace_func_probe *probe;
4528 struct ftrace_glob func_g;
4529 struct ftrace_hash **orig_hash;
4530 struct ftrace_hash *old_hash;
4531 struct ftrace_hash *hash = NULL;
4532 struct hlist_node *tmp;
4533 struct hlist_head hhd;
4534 char str[KSYM_SYMBOL_LEN];
4536 int i, ret = -ENODEV;
4539 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4540 func_g.search = NULL;
4544 func_g.type = filter_parse_regex(glob, strlen(glob),
4545 &func_g.search, ¬);
4546 func_g.len = strlen(func_g.search);
4548 /* we do not support '!' for function probes */
4553 mutex_lock(&ftrace_lock);
4554 /* Check if the probe_ops is already registered */
4555 list_for_each_entry(probe, &tr->func_probes, list) {
4556 if (probe->probe_ops == probe_ops)
4559 if (&probe->list == &tr->func_probes)
4560 goto err_unlock_ftrace;
4563 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4564 goto err_unlock_ftrace;
4566 acquire_probe_locked(probe);
4568 mutex_unlock(&ftrace_lock);
4570 mutex_lock(&probe->ops.func_hash->regex_lock);
4572 orig_hash = &probe->ops.func_hash->filter_hash;
4573 old_hash = *orig_hash;
4575 if (ftrace_hash_empty(old_hash))
4578 old_hash_ops.filter_hash = old_hash;
4579 /* Probes only have filters */
4580 old_hash_ops.notrace_hash = NULL;
4583 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4587 INIT_HLIST_HEAD(&hhd);
4589 size = 1 << hash->size_bits;
4590 for (i = 0; i < size; i++) {
4591 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4593 if (func_g.search) {
4594 kallsyms_lookup(entry->ip, NULL, NULL,
4596 if (!ftrace_match(str, &func_g))
4600 remove_hash_entry(hash, entry);
4601 hlist_add_head(&entry->hlist, &hhd);
4605 /* Nothing found? */
4611 mutex_lock(&ftrace_lock);
4613 WARN_ON(probe->ref < count);
4615 probe->ref -= count;
4617 if (ftrace_hash_empty(hash))
4618 ftrace_shutdown(&probe->ops, 0);
4620 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4623 /* still need to update the function call sites */
4624 if (ftrace_enabled && !ftrace_hash_empty(hash))
4625 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4627 synchronize_sched();
4629 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4630 hlist_del(&entry->hlist);
4631 if (probe_ops->free)
4632 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4635 mutex_unlock(&ftrace_lock);
4638 mutex_unlock(&probe->ops.func_hash->regex_lock);
4639 free_ftrace_hash(hash);
4641 release_probe(probe);
4646 mutex_unlock(&ftrace_lock);
4650 void clear_ftrace_function_probes(struct trace_array *tr)
4652 struct ftrace_func_probe *probe, *n;
4654 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4655 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4658 static LIST_HEAD(ftrace_commands);
4659 static DEFINE_MUTEX(ftrace_cmd_mutex);
4662 * Currently we only register ftrace commands from __init, so mark this
4665 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4667 struct ftrace_func_command *p;
4670 mutex_lock(&ftrace_cmd_mutex);
4671 list_for_each_entry(p, &ftrace_commands, list) {
4672 if (strcmp(cmd->name, p->name) == 0) {
4677 list_add(&cmd->list, &ftrace_commands);
4679 mutex_unlock(&ftrace_cmd_mutex);
4685 * Currently we only unregister ftrace commands from __init, so mark
4688 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4690 struct ftrace_func_command *p, *n;
4693 mutex_lock(&ftrace_cmd_mutex);
4694 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4695 if (strcmp(cmd->name, p->name) == 0) {
4697 list_del_init(&p->list);
4702 mutex_unlock(&ftrace_cmd_mutex);
4707 static int ftrace_process_regex(struct ftrace_iterator *iter,
4708 char *buff, int len, int enable)
4710 struct ftrace_hash *hash = iter->hash;
4711 struct trace_array *tr = iter->ops->private;
4712 char *func, *command, *next = buff;
4713 struct ftrace_func_command *p;
4716 func = strsep(&next, ":");
4719 ret = ftrace_match_records(hash, func, len);
4729 command = strsep(&next, ":");
4731 mutex_lock(&ftrace_cmd_mutex);
4732 list_for_each_entry(p, &ftrace_commands, list) {
4733 if (strcmp(p->name, command) == 0) {
4734 ret = p->func(tr, hash, func, command, next, enable);
4739 mutex_unlock(&ftrace_cmd_mutex);
4745 ftrace_regex_write(struct file *file, const char __user *ubuf,
4746 size_t cnt, loff_t *ppos, int enable)
4748 struct ftrace_iterator *iter;
4749 struct trace_parser *parser;
4755 if (file->f_mode & FMODE_READ) {
4756 struct seq_file *m = file->private_data;
4759 iter = file->private_data;
4761 if (unlikely(ftrace_disabled))
4764 /* iter->hash is a local copy, so we don't need regex_lock */
4766 parser = &iter->parser;
4767 read = trace_get_user(parser, ubuf, cnt, ppos);
4769 if (read >= 0 && trace_parser_loaded(parser) &&
4770 !trace_parser_cont(parser)) {
4771 ret = ftrace_process_regex(iter, parser->buffer,
4772 parser->idx, enable);
4773 trace_parser_clear(parser);
4784 ftrace_filter_write(struct file *file, const char __user *ubuf,
4785 size_t cnt, loff_t *ppos)
4787 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4791 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4792 size_t cnt, loff_t *ppos)
4794 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4798 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4800 struct ftrace_func_entry *entry;
4802 if (!ftrace_location(ip))
4806 entry = ftrace_lookup_ip(hash, ip);
4809 free_hash_entry(hash, entry);
4813 return add_hash_entry(hash, ip);
4817 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4818 unsigned long ip, int remove, int reset, int enable)
4820 struct ftrace_hash **orig_hash;
4821 struct ftrace_hash *hash;
4824 if (unlikely(ftrace_disabled))
4827 mutex_lock(&ops->func_hash->regex_lock);
4830 orig_hash = &ops->func_hash->filter_hash;
4832 orig_hash = &ops->func_hash->notrace_hash;
4835 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4837 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4841 goto out_regex_unlock;
4844 if (buf && !ftrace_match_records(hash, buf, len)) {
4846 goto out_regex_unlock;
4849 ret = ftrace_match_addr(hash, ip, remove);
4851 goto out_regex_unlock;
4854 mutex_lock(&ftrace_lock);
4855 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4856 mutex_unlock(&ftrace_lock);
4859 mutex_unlock(&ops->func_hash->regex_lock);
4861 free_ftrace_hash(hash);
4866 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4867 int reset, int enable)
4869 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4873 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4874 * @ops - the ops to set the filter with
4875 * @ip - the address to add to or remove from the filter.
4876 * @remove - non zero to remove the ip from the filter
4877 * @reset - non zero to reset all filters before applying this filter.
4879 * Filters denote which functions should be enabled when tracing is enabled
4880 * If @ip is NULL, it failes to update filter.
4882 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4883 int remove, int reset)
4885 ftrace_ops_init(ops);
4886 return ftrace_set_addr(ops, ip, remove, reset, 1);
4888 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4891 * ftrace_ops_set_global_filter - setup ops to use global filters
4892 * @ops - the ops which will use the global filters
4894 * ftrace users who need global function trace filtering should call this.
4895 * It can set the global filter only if ops were not initialized before.
4897 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4899 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4902 ftrace_ops_init(ops);
4903 ops->func_hash = &global_ops.local_hash;
4905 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4908 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4909 int reset, int enable)
4911 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4915 * ftrace_set_filter - set a function to filter on in ftrace
4916 * @ops - the ops to set the filter with
4917 * @buf - the string that holds the function filter text.
4918 * @len - the length of the string.
4919 * @reset - non zero to reset all filters before applying this filter.
4921 * Filters denote which functions should be enabled when tracing is enabled.
4922 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4924 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4927 ftrace_ops_init(ops);
4928 return ftrace_set_regex(ops, buf, len, reset, 1);
4930 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4933 * ftrace_set_notrace - set a function to not trace in ftrace
4934 * @ops - the ops to set the notrace filter with
4935 * @buf - the string that holds the function notrace text.
4936 * @len - the length of the string.
4937 * @reset - non zero to reset all filters before applying this filter.
4939 * Notrace Filters denote which functions should not be enabled when tracing
4940 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4943 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4946 ftrace_ops_init(ops);
4947 return ftrace_set_regex(ops, buf, len, reset, 0);
4949 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4951 * ftrace_set_global_filter - set a function to filter on with global tracers
4952 * @buf - the string that holds the function filter text.
4953 * @len - the length of the string.
4954 * @reset - non zero to reset all filters before applying this filter.
4956 * Filters denote which functions should be enabled when tracing is enabled.
4957 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4959 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4961 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4963 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4966 * ftrace_set_global_notrace - set a function to not trace with global tracers
4967 * @buf - the string that holds the function notrace text.
4968 * @len - the length of the string.
4969 * @reset - non zero to reset all filters before applying this filter.
4971 * Notrace Filters denote which functions should not be enabled when tracing
4972 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4975 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4977 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4979 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4982 * command line interface to allow users to set filters on boot up.
4984 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4985 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4986 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4988 /* Used by function selftest to not test if filter is set */
4989 bool ftrace_filter_param __initdata;
4991 static int __init set_ftrace_notrace(char *str)
4993 ftrace_filter_param = true;
4994 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4997 __setup("ftrace_notrace=", set_ftrace_notrace);
4999 static int __init set_ftrace_filter(char *str)
5001 ftrace_filter_param = true;
5002 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5005 __setup("ftrace_filter=", set_ftrace_filter);
5007 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5008 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5009 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5010 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5012 static int __init set_graph_function(char *str)
5014 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5017 __setup("ftrace_graph_filter=", set_graph_function);
5019 static int __init set_graph_notrace_function(char *str)
5021 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5024 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5026 static int __init set_graph_max_depth_function(char *str)
5030 fgraph_max_depth = simple_strtoul(str, NULL, 0);
5033 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5035 static void __init set_ftrace_early_graph(char *buf, int enable)
5039 struct ftrace_hash *hash;
5041 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5046 func = strsep(&buf, ",");
5047 /* we allow only one expression at a time */
5048 ret = ftrace_graph_set_hash(hash, func);
5050 printk(KERN_DEBUG "ftrace: function %s not "
5051 "traceable\n", func);
5055 ftrace_graph_hash = hash;
5057 ftrace_graph_notrace_hash = hash;
5059 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5062 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5066 ftrace_ops_init(ops);
5069 func = strsep(&buf, ",");
5070 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5074 static void __init set_ftrace_early_filters(void)
5076 if (ftrace_filter_buf[0])
5077 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5078 if (ftrace_notrace_buf[0])
5079 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5080 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5081 if (ftrace_graph_buf[0])
5082 set_ftrace_early_graph(ftrace_graph_buf, 1);
5083 if (ftrace_graph_notrace_buf[0])
5084 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5085 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5088 int ftrace_regex_release(struct inode *inode, struct file *file)
5090 struct seq_file *m = (struct seq_file *)file->private_data;
5091 struct ftrace_iterator *iter;
5092 struct ftrace_hash **orig_hash;
5093 struct trace_parser *parser;
5097 if (file->f_mode & FMODE_READ) {
5099 seq_release(inode, file);
5101 iter = file->private_data;
5103 parser = &iter->parser;
5104 if (trace_parser_loaded(parser)) {
5105 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5107 parser->buffer[parser->idx] = 0;
5108 ftrace_process_regex(iter, parser->buffer,
5109 parser->idx, enable);
5112 trace_parser_put(parser);
5114 mutex_lock(&iter->ops->func_hash->regex_lock);
5116 if (file->f_mode & FMODE_WRITE) {
5117 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5120 orig_hash = &iter->ops->func_hash->filter_hash;
5121 if (iter->tr && !list_empty(&iter->tr->mod_trace))
5122 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5124 orig_hash = &iter->ops->func_hash->notrace_hash;
5126 mutex_lock(&ftrace_lock);
5127 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5128 iter->hash, filter_hash);
5129 mutex_unlock(&ftrace_lock);
5131 /* For read only, the hash is the ops hash */
5135 mutex_unlock(&iter->ops->func_hash->regex_lock);
5136 free_ftrace_hash(iter->hash);
5138 trace_array_put(iter->tr);
5144 static const struct file_operations ftrace_avail_fops = {
5145 .open = ftrace_avail_open,
5147 .llseek = seq_lseek,
5148 .release = seq_release_private,
5151 static const struct file_operations ftrace_enabled_fops = {
5152 .open = ftrace_enabled_open,
5154 .llseek = seq_lseek,
5155 .release = seq_release_private,
5158 static const struct file_operations ftrace_filter_fops = {
5159 .open = ftrace_filter_open,
5161 .write = ftrace_filter_write,
5162 .llseek = tracing_lseek,
5163 .release = ftrace_regex_release,
5166 static const struct file_operations ftrace_notrace_fops = {
5167 .open = ftrace_notrace_open,
5169 .write = ftrace_notrace_write,
5170 .llseek = tracing_lseek,
5171 .release = ftrace_regex_release,
5174 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5176 static DEFINE_MUTEX(graph_lock);
5178 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5179 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5181 enum graph_filter_type {
5182 GRAPH_FILTER_NOTRACE = 0,
5183 GRAPH_FILTER_FUNCTION,
5186 #define FTRACE_GRAPH_EMPTY ((void *)1)
5188 struct ftrace_graph_data {
5189 struct ftrace_hash *hash;
5190 struct ftrace_func_entry *entry;
5191 int idx; /* for hash table iteration */
5192 enum graph_filter_type type;
5193 struct ftrace_hash *new_hash;
5194 const struct seq_operations *seq_ops;
5195 struct trace_parser parser;
5199 __g_next(struct seq_file *m, loff_t *pos)
5201 struct ftrace_graph_data *fgd = m->private;
5202 struct ftrace_func_entry *entry = fgd->entry;
5203 struct hlist_head *head;
5204 int i, idx = fgd->idx;
5206 if (*pos >= fgd->hash->count)
5210 hlist_for_each_entry_continue(entry, hlist) {
5218 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5219 head = &fgd->hash->buckets[i];
5220 hlist_for_each_entry(entry, head, hlist) {
5230 g_next(struct seq_file *m, void *v, loff_t *pos)
5233 return __g_next(m, pos);
5236 static void *g_start(struct seq_file *m, loff_t *pos)
5238 struct ftrace_graph_data *fgd = m->private;
5240 mutex_lock(&graph_lock);
5242 if (fgd->type == GRAPH_FILTER_FUNCTION)
5243 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5244 lockdep_is_held(&graph_lock));
5246 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5247 lockdep_is_held(&graph_lock));
5249 /* Nothing, tell g_show to print all functions are enabled */
5250 if (ftrace_hash_empty(fgd->hash) && !*pos)
5251 return FTRACE_GRAPH_EMPTY;
5255 return __g_next(m, pos);
5258 static void g_stop(struct seq_file *m, void *p)
5260 mutex_unlock(&graph_lock);
5263 static int g_show(struct seq_file *m, void *v)
5265 struct ftrace_func_entry *entry = v;
5270 if (entry == FTRACE_GRAPH_EMPTY) {
5271 struct ftrace_graph_data *fgd = m->private;
5273 if (fgd->type == GRAPH_FILTER_FUNCTION)
5274 seq_puts(m, "#### all functions enabled ####\n");
5276 seq_puts(m, "#### no functions disabled ####\n");
5280 seq_printf(m, "%ps\n", (void *)entry->ip);
5285 static const struct seq_operations ftrace_graph_seq_ops = {
5293 __ftrace_graph_open(struct inode *inode, struct file *file,
5294 struct ftrace_graph_data *fgd)
5297 struct ftrace_hash *new_hash = NULL;
5299 if (file->f_mode & FMODE_WRITE) {
5300 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5302 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5305 if (file->f_flags & O_TRUNC)
5306 new_hash = alloc_ftrace_hash(size_bits);
5308 new_hash = alloc_and_copy_ftrace_hash(size_bits,
5316 if (file->f_mode & FMODE_READ) {
5317 ret = seq_open(file, &ftrace_graph_seq_ops);
5319 struct seq_file *m = file->private_data;
5323 free_ftrace_hash(new_hash);
5327 file->private_data = fgd;
5330 if (ret < 0 && file->f_mode & FMODE_WRITE)
5331 trace_parser_put(&fgd->parser);
5333 fgd->new_hash = new_hash;
5336 * All uses of fgd->hash must be taken with the graph_lock
5337 * held. The graph_lock is going to be released, so force
5338 * fgd->hash to be reinitialized when it is taken again.
5346 ftrace_graph_open(struct inode *inode, struct file *file)
5348 struct ftrace_graph_data *fgd;
5351 if (unlikely(ftrace_disabled))
5354 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5358 mutex_lock(&graph_lock);
5360 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5361 lockdep_is_held(&graph_lock));
5362 fgd->type = GRAPH_FILTER_FUNCTION;
5363 fgd->seq_ops = &ftrace_graph_seq_ops;
5365 ret = __ftrace_graph_open(inode, file, fgd);
5369 mutex_unlock(&graph_lock);
5374 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5376 struct ftrace_graph_data *fgd;
5379 if (unlikely(ftrace_disabled))
5382 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5386 mutex_lock(&graph_lock);
5388 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5389 lockdep_is_held(&graph_lock));
5390 fgd->type = GRAPH_FILTER_NOTRACE;
5391 fgd->seq_ops = &ftrace_graph_seq_ops;
5393 ret = __ftrace_graph_open(inode, file, fgd);
5397 mutex_unlock(&graph_lock);
5402 ftrace_graph_release(struct inode *inode, struct file *file)
5404 struct ftrace_graph_data *fgd;
5405 struct ftrace_hash *old_hash, *new_hash;
5406 struct trace_parser *parser;
5409 if (file->f_mode & FMODE_READ) {
5410 struct seq_file *m = file->private_data;
5413 seq_release(inode, file);
5415 fgd = file->private_data;
5419 if (file->f_mode & FMODE_WRITE) {
5421 parser = &fgd->parser;
5423 if (trace_parser_loaded((parser))) {
5424 parser->buffer[parser->idx] = 0;
5425 ret = ftrace_graph_set_hash(fgd->new_hash,
5429 trace_parser_put(parser);
5431 new_hash = __ftrace_hash_move(fgd->new_hash);
5437 mutex_lock(&graph_lock);
5439 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5440 old_hash = rcu_dereference_protected(ftrace_graph_hash,
5441 lockdep_is_held(&graph_lock));
5442 rcu_assign_pointer(ftrace_graph_hash, new_hash);
5444 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5445 lockdep_is_held(&graph_lock));
5446 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5449 mutex_unlock(&graph_lock);
5452 * We need to do a hard force of sched synchronization.
5453 * This is because we use preempt_disable() to do RCU, but
5454 * the function tracers can be called where RCU is not watching
5455 * (like before user_exit()). We can not rely on the RCU
5456 * infrastructure to do the synchronization, thus we must do it
5459 schedule_on_each_cpu(ftrace_sync);
5461 free_ftrace_hash(old_hash);
5465 free_ftrace_hash(fgd->new_hash);
5472 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5474 struct ftrace_glob func_g;
5475 struct dyn_ftrace *rec;
5476 struct ftrace_page *pg;
5477 struct ftrace_func_entry *entry;
5482 func_g.type = filter_parse_regex(buffer, strlen(buffer),
5483 &func_g.search, ¬);
5485 func_g.len = strlen(func_g.search);
5487 mutex_lock(&ftrace_lock);
5489 if (unlikely(ftrace_disabled)) {
5490 mutex_unlock(&ftrace_lock);
5494 do_for_each_ftrace_rec(pg, rec) {
5496 if (rec->flags & FTRACE_FL_DISABLED)
5499 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5500 entry = ftrace_lookup_ip(hash, rec->ip);
5507 if (add_hash_entry(hash, rec->ip) < 0)
5511 free_hash_entry(hash, entry);
5516 } while_for_each_ftrace_rec();
5518 mutex_unlock(&ftrace_lock);
5527 ftrace_graph_write(struct file *file, const char __user *ubuf,
5528 size_t cnt, loff_t *ppos)
5530 ssize_t read, ret = 0;
5531 struct ftrace_graph_data *fgd = file->private_data;
5532 struct trace_parser *parser;
5537 /* Read mode uses seq functions */
5538 if (file->f_mode & FMODE_READ) {
5539 struct seq_file *m = file->private_data;
5543 parser = &fgd->parser;
5545 read = trace_get_user(parser, ubuf, cnt, ppos);
5547 if (read >= 0 && trace_parser_loaded(parser) &&
5548 !trace_parser_cont(parser)) {
5550 ret = ftrace_graph_set_hash(fgd->new_hash,
5552 trace_parser_clear(parser);
5561 static const struct file_operations ftrace_graph_fops = {
5562 .open = ftrace_graph_open,
5564 .write = ftrace_graph_write,
5565 .llseek = tracing_lseek,
5566 .release = ftrace_graph_release,
5569 static const struct file_operations ftrace_graph_notrace_fops = {
5570 .open = ftrace_graph_notrace_open,
5572 .write = ftrace_graph_write,
5573 .llseek = tracing_lseek,
5574 .release = ftrace_graph_release,
5576 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5578 void ftrace_create_filter_files(struct ftrace_ops *ops,
5579 struct dentry *parent)
5582 trace_create_file("set_ftrace_filter", 0644, parent,
5583 ops, &ftrace_filter_fops);
5585 trace_create_file("set_ftrace_notrace", 0644, parent,
5586 ops, &ftrace_notrace_fops);
5590 * The name "destroy_filter_files" is really a misnomer. Although
5591 * in the future, it may actualy delete the files, but this is
5592 * really intended to make sure the ops passed in are disabled
5593 * and that when this function returns, the caller is free to
5596 * The "destroy" name is only to match the "create" name that this
5597 * should be paired with.
5599 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5601 mutex_lock(&ftrace_lock);
5602 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5603 ftrace_shutdown(ops, 0);
5604 ops->flags |= FTRACE_OPS_FL_DELETED;
5605 ftrace_free_filter(ops);
5606 mutex_unlock(&ftrace_lock);
5609 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5612 trace_create_file("available_filter_functions", 0444,
5613 d_tracer, NULL, &ftrace_avail_fops);
5615 trace_create_file("enabled_functions", 0444,
5616 d_tracer, NULL, &ftrace_enabled_fops);
5618 ftrace_create_filter_files(&global_ops, d_tracer);
5620 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5621 trace_create_file("set_graph_function", 0444, d_tracer,
5623 &ftrace_graph_fops);
5624 trace_create_file("set_graph_notrace", 0444, d_tracer,
5626 &ftrace_graph_notrace_fops);
5627 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5632 static int ftrace_cmp_ips(const void *a, const void *b)
5634 const unsigned long *ipa = a;
5635 const unsigned long *ipb = b;
5644 static int ftrace_process_locs(struct module *mod,
5645 unsigned long *start,
5648 struct ftrace_page *start_pg;
5649 struct ftrace_page *pg;
5650 struct dyn_ftrace *rec;
5651 unsigned long count;
5654 unsigned long flags = 0; /* Shut up gcc */
5657 count = end - start;
5662 sort(start, count, sizeof(*start),
5663 ftrace_cmp_ips, NULL);
5665 start_pg = ftrace_allocate_pages(count);
5669 mutex_lock(&ftrace_lock);
5672 * Core and each module needs their own pages, as
5673 * modules will free them when they are removed.
5674 * Force a new page to be allocated for modules.
5677 WARN_ON(ftrace_pages || ftrace_pages_start);
5678 /* First initialization */
5679 ftrace_pages = ftrace_pages_start = start_pg;
5684 if (WARN_ON(ftrace_pages->next)) {
5685 /* Hmm, we have free pages? */
5686 while (ftrace_pages->next)
5687 ftrace_pages = ftrace_pages->next;
5690 ftrace_pages->next = start_pg;
5696 addr = ftrace_call_adjust(*p++);
5698 * Some architecture linkers will pad between
5699 * the different mcount_loc sections of different
5700 * object files to satisfy alignments.
5701 * Skip any NULL pointers.
5706 if (pg->index == pg->size) {
5707 /* We should have allocated enough */
5708 if (WARN_ON(!pg->next))
5713 rec = &pg->records[pg->index++];
5717 /* We should have used all pages */
5720 /* Assign the last page to ftrace_pages */
5724 * We only need to disable interrupts on start up
5725 * because we are modifying code that an interrupt
5726 * may execute, and the modification is not atomic.
5727 * But for modules, nothing runs the code we modify
5728 * until we are finished with it, and there's no
5729 * reason to cause large interrupt latencies while we do it.
5732 local_irq_save(flags);
5733 ftrace_update_code(mod, start_pg);
5735 local_irq_restore(flags);
5738 mutex_unlock(&ftrace_lock);
5743 #ifdef CONFIG_MODULES
5745 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5747 static int referenced_filters(struct dyn_ftrace *rec)
5749 struct ftrace_ops *ops;
5752 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5753 if (ops_references_rec(ops, rec)) {
5755 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
5756 rec->flags |= FTRACE_FL_REGS;
5764 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5766 struct ftrace_func_entry *entry;
5767 struct dyn_ftrace *rec;
5770 if (ftrace_hash_empty(hash))
5773 for (i = 0; i < pg->index; i++) {
5774 rec = &pg->records[i];
5775 entry = __ftrace_lookup_ip(hash, rec->ip);
5777 * Do not allow this rec to match again.
5778 * Yeah, it may waste some memory, but will be removed
5779 * if/when the hash is modified again.
5786 /* Clear any records from hashs */
5787 static void clear_mod_from_hashes(struct ftrace_page *pg)
5789 struct trace_array *tr;
5791 mutex_lock(&trace_types_lock);
5792 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5793 if (!tr->ops || !tr->ops->func_hash)
5795 mutex_lock(&tr->ops->func_hash->regex_lock);
5796 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5797 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5798 mutex_unlock(&tr->ops->func_hash->regex_lock);
5800 mutex_unlock(&trace_types_lock);
5803 void ftrace_release_mod(struct module *mod)
5805 struct dyn_ftrace *rec;
5806 struct ftrace_page **last_pg;
5807 struct ftrace_page *tmp_page = NULL;
5808 struct ftrace_page *pg;
5811 mutex_lock(&ftrace_lock);
5813 if (ftrace_disabled)
5817 * Each module has its own ftrace_pages, remove
5818 * them from the list.
5820 last_pg = &ftrace_pages_start;
5821 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5822 rec = &pg->records[0];
5823 if (within_module_core(rec->ip, mod)) {
5825 * As core pages are first, the first
5826 * page should never be a module page.
5828 if (WARN_ON(pg == ftrace_pages_start))
5831 /* Check if we are deleting the last page */
5832 if (pg == ftrace_pages)
5833 ftrace_pages = next_to_ftrace_page(last_pg);
5835 ftrace_update_tot_cnt -= pg->index;
5836 *last_pg = pg->next;
5838 pg->next = tmp_page;
5841 last_pg = &pg->next;
5844 mutex_unlock(&ftrace_lock);
5846 for (pg = tmp_page; pg; pg = tmp_page) {
5848 /* Needs to be called outside of ftrace_lock */
5849 clear_mod_from_hashes(pg);
5851 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5852 free_pages((unsigned long)pg->records, order);
5853 tmp_page = pg->next;
5858 void ftrace_module_enable(struct module *mod)
5860 struct dyn_ftrace *rec;
5861 struct ftrace_page *pg;
5863 mutex_lock(&ftrace_lock);
5865 if (ftrace_disabled)
5869 * If the tracing is enabled, go ahead and enable the record.
5871 * The reason not to enable the record immediatelly is the
5872 * inherent check of ftrace_make_nop/ftrace_make_call for
5873 * correct previous instructions. Making first the NOP
5874 * conversion puts the module to the correct state, thus
5875 * passing the ftrace_make_call check.
5877 * We also delay this to after the module code already set the
5878 * text to read-only, as we now need to set it back to read-write
5879 * so that we can modify the text.
5881 if (ftrace_start_up)
5882 ftrace_arch_code_modify_prepare();
5884 do_for_each_ftrace_rec(pg, rec) {
5887 * do_for_each_ftrace_rec() is a double loop.
5888 * module text shares the pg. If a record is
5889 * not part of this module, then skip this pg,
5890 * which the "break" will do.
5892 if (!within_module_core(rec->ip, mod))
5898 * When adding a module, we need to check if tracers are
5899 * currently enabled and if they are, and can trace this record,
5900 * we need to enable the module functions as well as update the
5901 * reference counts for those function records.
5903 if (ftrace_start_up)
5904 cnt += referenced_filters(rec);
5906 rec->flags &= ~FTRACE_FL_DISABLED;
5909 if (ftrace_start_up && cnt) {
5910 int failed = __ftrace_replace_code(rec, 1);
5912 ftrace_bug(failed, rec);
5917 } while_for_each_ftrace_rec();
5920 if (ftrace_start_up)
5921 ftrace_arch_code_modify_post_process();
5924 mutex_unlock(&ftrace_lock);
5926 process_cached_mods(mod->name);
5929 void ftrace_module_init(struct module *mod)
5931 if (ftrace_disabled || !mod->num_ftrace_callsites)
5934 ftrace_process_locs(mod, mod->ftrace_callsites,
5935 mod->ftrace_callsites + mod->num_ftrace_callsites);
5937 #endif /* CONFIG_MODULES */
5939 void __init ftrace_free_init_mem(void)
5941 unsigned long start = (unsigned long)(&__init_begin);
5942 unsigned long end = (unsigned long)(&__init_end);
5943 struct ftrace_page **last_pg = &ftrace_pages_start;
5944 struct ftrace_page *pg;
5945 struct dyn_ftrace *rec;
5946 struct dyn_ftrace key;
5950 key.flags = end; /* overload flags, as it is unsigned long */
5952 mutex_lock(&ftrace_lock);
5954 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
5955 if (end < pg->records[0].ip ||
5956 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
5959 rec = bsearch(&key, pg->records, pg->index,
5960 sizeof(struct dyn_ftrace),
5965 ftrace_update_tot_cnt--;
5967 *last_pg = pg->next;
5968 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5969 free_pages((unsigned long)pg->records, order);
5971 pg = container_of(last_pg, struct ftrace_page, next);
5976 memmove(rec, rec + 1,
5977 (pg->index - (rec - pg->records)) * sizeof(*rec));
5978 /* More than one function may be in this block */
5981 mutex_unlock(&ftrace_lock);
5984 void __init ftrace_init(void)
5986 extern unsigned long __start_mcount_loc[];
5987 extern unsigned long __stop_mcount_loc[];
5988 unsigned long count, flags;
5991 local_irq_save(flags);
5992 ret = ftrace_dyn_arch_init();
5993 local_irq_restore(flags);
5997 count = __stop_mcount_loc - __start_mcount_loc;
5999 pr_info("ftrace: No functions to be traced?\n");
6003 pr_info("ftrace: allocating %ld entries in %ld pages\n",
6004 count, count / ENTRIES_PER_PAGE + 1);
6006 last_ftrace_enabled = ftrace_enabled = 1;
6008 ret = ftrace_process_locs(NULL,
6012 set_ftrace_early_filters();
6016 ftrace_disabled = 1;
6019 /* Do nothing if arch does not support this */
6020 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6024 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6026 arch_ftrace_update_trampoline(ops);
6029 void ftrace_init_trace_array(struct trace_array *tr)
6031 INIT_LIST_HEAD(&tr->func_probes);
6032 INIT_LIST_HEAD(&tr->mod_trace);
6033 INIT_LIST_HEAD(&tr->mod_notrace);
6037 static struct ftrace_ops global_ops = {
6038 .func = ftrace_stub,
6039 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6040 FTRACE_OPS_FL_INITIALIZED |
6044 static int __init ftrace_nodyn_init(void)
6049 core_initcall(ftrace_nodyn_init);
6051 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6052 static inline void ftrace_startup_enable(int command) { }
6053 static inline void ftrace_startup_all(int command) { }
6054 /* Keep as macros so we do not need to define the commands */
6055 # define ftrace_startup(ops, command) \
6057 int ___ret = __register_ftrace_function(ops); \
6059 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
6062 # define ftrace_shutdown(ops, command) \
6064 int ___ret = __unregister_ftrace_function(ops); \
6066 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
6070 # define ftrace_startup_sysctl() do { } while (0)
6071 # define ftrace_shutdown_sysctl() do { } while (0)
6074 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
6079 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6083 #endif /* CONFIG_DYNAMIC_FTRACE */
6085 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6087 tr->ops = &global_ops;
6088 tr->ops->private = tr;
6089 ftrace_init_trace_array(tr);
6092 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6094 /* If we filter on pids, update to use the pid function */
6095 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6096 if (WARN_ON(tr->ops->func != ftrace_stub))
6097 printk("ftrace ops had %pS for function\n",
6100 tr->ops->func = func;
6101 tr->ops->private = tr;
6104 void ftrace_reset_array_ops(struct trace_array *tr)
6106 tr->ops->func = ftrace_stub;
6109 static nokprobe_inline void
6110 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6111 struct ftrace_ops *ignored, struct pt_regs *regs)
6113 struct ftrace_ops *op;
6116 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6121 * Some of the ops may be dynamically allocated,
6122 * they must be freed after a synchronize_sched().
6124 preempt_disable_notrace();
6126 do_for_each_ftrace_op(op, ftrace_ops_list) {
6128 * Check the following for each ops before calling their func:
6129 * if RCU flag is set, then rcu_is_watching() must be true
6130 * if PER_CPU is set, then ftrace_function_local_disable()
6132 * Otherwise test if the ip matches the ops filter
6134 * If any of the above fails then the op->func() is not executed.
6136 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6137 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
6138 !ftrace_function_local_disabled(op)) &&
6139 ftrace_ops_test(op, ip, regs)) {
6141 if (FTRACE_WARN_ON(!op->func)) {
6142 pr_warn("op=%p %pS\n", op, op);
6145 op->func(ip, parent_ip, op, regs);
6147 } while_for_each_ftrace_op(op);
6149 preempt_enable_notrace();
6150 trace_clear_recursion(bit);
6154 * Some archs only support passing ip and parent_ip. Even though
6155 * the list function ignores the op parameter, we do not want any
6156 * C side effects, where a function is called without the caller
6157 * sending a third parameter.
6158 * Archs are to support both the regs and ftrace_ops at the same time.
6159 * If they support ftrace_ops, it is assumed they support regs.
6160 * If call backs want to use regs, they must either check for regs
6161 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6162 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6163 * An architecture can pass partial regs with ftrace_ops and still
6164 * set the ARCH_SUPPORTS_FTRACE_OPS.
6166 #if ARCH_SUPPORTS_FTRACE_OPS
6167 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6168 struct ftrace_ops *op, struct pt_regs *regs)
6170 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6172 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6174 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6176 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6178 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6182 * If there's only one function registered but it does not support
6183 * recursion, needs RCU protection and/or requires per cpu handling, then
6184 * this function will be called by the mcount trampoline.
6186 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6187 struct ftrace_ops *op, struct pt_regs *regs)
6191 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6195 preempt_disable_notrace();
6197 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6198 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
6199 !ftrace_function_local_disabled(op))) {
6200 op->func(ip, parent_ip, op, regs);
6203 preempt_enable_notrace();
6204 trace_clear_recursion(bit);
6206 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6209 * ftrace_ops_get_func - get the function a trampoline should call
6210 * @ops: the ops to get the function for
6212 * Normally the mcount trampoline will call the ops->func, but there
6213 * are times that it should not. For example, if the ops does not
6214 * have its own recursion protection, then it should call the
6215 * ftrace_ops_assist_func() instead.
6217 * Returns the function that the trampoline should call for @ops.
6219 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6222 * If the function does not handle recursion, needs to be RCU safe,
6223 * or does per cpu logic, then we need to call the assist handler.
6225 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6226 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
6227 return ftrace_ops_assist_func;
6233 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6234 struct task_struct *prev, struct task_struct *next)
6236 struct trace_array *tr = data;
6237 struct trace_pid_list *pid_list;
6239 pid_list = rcu_dereference_sched(tr->function_pids);
6241 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6242 trace_ignore_this_task(pid_list, next));
6246 ftrace_pid_follow_sched_process_fork(void *data,
6247 struct task_struct *self,
6248 struct task_struct *task)
6250 struct trace_pid_list *pid_list;
6251 struct trace_array *tr = data;
6253 pid_list = rcu_dereference_sched(tr->function_pids);
6254 trace_filter_add_remove_task(pid_list, self, task);
6258 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6260 struct trace_pid_list *pid_list;
6261 struct trace_array *tr = data;
6263 pid_list = rcu_dereference_sched(tr->function_pids);
6264 trace_filter_add_remove_task(pid_list, NULL, task);
6267 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6270 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6272 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
6275 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6277 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
6282 static void clear_ftrace_pids(struct trace_array *tr)
6284 struct trace_pid_list *pid_list;
6287 pid_list = rcu_dereference_protected(tr->function_pids,
6288 lockdep_is_held(&ftrace_lock));
6292 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6294 for_each_possible_cpu(cpu)
6295 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6297 rcu_assign_pointer(tr->function_pids, NULL);
6299 /* Wait till all users are no longer using pid filtering */
6300 synchronize_sched();
6302 trace_free_pid_list(pid_list);
6305 void ftrace_clear_pids(struct trace_array *tr)
6307 mutex_lock(&ftrace_lock);
6309 clear_ftrace_pids(tr);
6311 mutex_unlock(&ftrace_lock);
6314 static void ftrace_pid_reset(struct trace_array *tr)
6316 mutex_lock(&ftrace_lock);
6317 clear_ftrace_pids(tr);
6319 ftrace_update_pid_func();
6320 ftrace_startup_all(0);
6322 mutex_unlock(&ftrace_lock);
6325 /* Greater than any max PID */
6326 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
6328 static void *fpid_start(struct seq_file *m, loff_t *pos)
6331 struct trace_pid_list *pid_list;
6332 struct trace_array *tr = m->private;
6334 mutex_lock(&ftrace_lock);
6335 rcu_read_lock_sched();
6337 pid_list = rcu_dereference_sched(tr->function_pids);
6340 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6342 return trace_pid_start(pid_list, pos);
6345 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6347 struct trace_array *tr = m->private;
6348 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6350 if (v == FTRACE_NO_PIDS) {
6354 return trace_pid_next(pid_list, v, pos);
6357 static void fpid_stop(struct seq_file *m, void *p)
6360 rcu_read_unlock_sched();
6361 mutex_unlock(&ftrace_lock);
6364 static int fpid_show(struct seq_file *m, void *v)
6366 if (v == FTRACE_NO_PIDS) {
6367 seq_puts(m, "no pid\n");
6371 return trace_pid_show(m, v);
6374 static const struct seq_operations ftrace_pid_sops = {
6375 .start = fpid_start,
6382 ftrace_pid_open(struct inode *inode, struct file *file)
6384 struct trace_array *tr = inode->i_private;
6388 if (trace_array_get(tr) < 0)
6391 if ((file->f_mode & FMODE_WRITE) &&
6392 (file->f_flags & O_TRUNC))
6393 ftrace_pid_reset(tr);
6395 ret = seq_open(file, &ftrace_pid_sops);
6397 trace_array_put(tr);
6399 m = file->private_data;
6400 /* copy tr over to seq ops */
6407 static void ignore_task_cpu(void *data)
6409 struct trace_array *tr = data;
6410 struct trace_pid_list *pid_list;
6413 * This function is called by on_each_cpu() while the
6414 * event_mutex is held.
6416 pid_list = rcu_dereference_protected(tr->function_pids,
6417 mutex_is_locked(&ftrace_lock));
6419 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6420 trace_ignore_this_task(pid_list, current));
6424 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6425 size_t cnt, loff_t *ppos)
6427 struct seq_file *m = filp->private_data;
6428 struct trace_array *tr = m->private;
6429 struct trace_pid_list *filtered_pids = NULL;
6430 struct trace_pid_list *pid_list;
6436 mutex_lock(&ftrace_lock);
6438 filtered_pids = rcu_dereference_protected(tr->function_pids,
6439 lockdep_is_held(&ftrace_lock));
6441 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6445 rcu_assign_pointer(tr->function_pids, pid_list);
6447 if (filtered_pids) {
6448 synchronize_sched();
6449 trace_free_pid_list(filtered_pids);
6450 } else if (pid_list) {
6451 /* Register a probe to set whether to ignore the tracing of a task */
6452 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6456 * Ignoring of pids is done at task switch. But we have to
6457 * check for those tasks that are currently running.
6458 * Always do this in case a pid was appended or removed.
6460 on_each_cpu(ignore_task_cpu, tr, 1);
6462 ftrace_update_pid_func();
6463 ftrace_startup_all(0);
6465 mutex_unlock(&ftrace_lock);
6474 ftrace_pid_release(struct inode *inode, struct file *file)
6476 struct trace_array *tr = inode->i_private;
6478 trace_array_put(tr);
6480 return seq_release(inode, file);
6483 static const struct file_operations ftrace_pid_fops = {
6484 .open = ftrace_pid_open,
6485 .write = ftrace_pid_write,
6487 .llseek = tracing_lseek,
6488 .release = ftrace_pid_release,
6491 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6493 trace_create_file("set_ftrace_pid", 0644, d_tracer,
6494 tr, &ftrace_pid_fops);
6497 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6498 struct dentry *d_tracer)
6500 /* Only the top level directory has the dyn_tracefs and profile */
6501 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6503 ftrace_init_dyn_tracefs(d_tracer);
6504 ftrace_profile_tracefs(d_tracer);
6508 * ftrace_kill - kill ftrace
6510 * This function should be used by panic code. It stops ftrace
6511 * but in a not so nice way. If you need to simply kill ftrace
6512 * from a non-atomic section, use ftrace_kill.
6514 void ftrace_kill(void)
6516 ftrace_disabled = 1;
6518 clear_ftrace_function();
6522 * Test if ftrace is dead or not.
6524 int ftrace_is_dead(void)
6526 return ftrace_disabled;
6530 * register_ftrace_function - register a function for profiling
6531 * @ops - ops structure that holds the function for profiling.
6533 * Register a function to be called by all functions in the
6536 * Note: @ops->func and all the functions it calls must be labeled
6537 * with "notrace", otherwise it will go into a
6540 int register_ftrace_function(struct ftrace_ops *ops)
6544 ftrace_ops_init(ops);
6546 mutex_lock(&ftrace_lock);
6548 ret = ftrace_startup(ops, 0);
6550 mutex_unlock(&ftrace_lock);
6554 EXPORT_SYMBOL_GPL(register_ftrace_function);
6557 * unregister_ftrace_function - unregister a function for profiling.
6558 * @ops - ops structure that holds the function to unregister
6560 * Unregister a function that was added to be called by ftrace profiling.
6562 int unregister_ftrace_function(struct ftrace_ops *ops)
6566 mutex_lock(&ftrace_lock);
6567 ret = ftrace_shutdown(ops, 0);
6568 mutex_unlock(&ftrace_lock);
6572 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6575 ftrace_enable_sysctl(struct ctl_table *table, int write,
6576 void __user *buffer, size_t *lenp,
6581 mutex_lock(&ftrace_lock);
6583 if (unlikely(ftrace_disabled))
6586 ret = proc_dointvec(table, write, buffer, lenp, ppos);
6588 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6591 last_ftrace_enabled = !!ftrace_enabled;
6593 if (ftrace_enabled) {
6595 /* we are starting ftrace again */
6596 if (rcu_dereference_protected(ftrace_ops_list,
6597 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6598 update_ftrace_function();
6600 ftrace_startup_sysctl();
6603 /* stopping ftrace calls (just send to ftrace_stub) */
6604 ftrace_trace_function = ftrace_stub;
6606 ftrace_shutdown_sysctl();
6610 mutex_unlock(&ftrace_lock);
6614 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6616 static struct ftrace_ops graph_ops = {
6617 .func = ftrace_stub,
6618 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
6619 FTRACE_OPS_FL_INITIALIZED |
6622 #ifdef FTRACE_GRAPH_TRAMP_ADDR
6623 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
6624 /* trampoline_size is only needed for dynamically allocated tramps */
6626 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
6629 void ftrace_graph_sleep_time_control(bool enable)
6631 fgraph_sleep_time = enable;
6634 void ftrace_graph_graph_time_control(bool enable)
6636 fgraph_graph_time = enable;
6639 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
6644 /* The callbacks that hook a function */
6645 trace_func_graph_ret_t ftrace_graph_return =
6646 (trace_func_graph_ret_t)ftrace_stub;
6647 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
6648 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
6650 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
6651 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
6655 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
6656 struct task_struct *g, *t;
6658 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
6659 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
6660 * sizeof(struct ftrace_ret_stack),
6662 if (!ret_stack_list[i]) {
6670 read_lock(&tasklist_lock);
6671 do_each_thread(g, t) {
6677 if (t->ret_stack == NULL) {
6678 atomic_set(&t->trace_overrun, 0);
6679 t->curr_ret_stack = -1;
6680 /* Make sure the tasks see the -1 first: */
6682 t->ret_stack = ret_stack_list[start++];
6684 } while_each_thread(g, t);
6687 read_unlock(&tasklist_lock);
6689 for (i = start; i < end; i++)
6690 kfree(ret_stack_list[i]);
6695 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
6696 struct task_struct *prev, struct task_struct *next)
6698 unsigned long long timestamp;
6702 * Does the user want to count the time a function was asleep.
6703 * If so, do not update the time stamps.
6705 if (fgraph_sleep_time)
6708 timestamp = trace_clock_local();
6710 prev->ftrace_timestamp = timestamp;
6712 /* only process tasks that we timestamped */
6713 if (!next->ftrace_timestamp)
6717 * Update all the counters in next to make up for the
6718 * time next was sleeping.
6720 timestamp -= next->ftrace_timestamp;
6722 for (index = next->curr_ret_stack; index >= 0; index--)
6723 next->ret_stack[index].calltime += timestamp;
6726 /* Allocate a return stack for each task */
6727 static int start_graph_tracing(void)
6729 struct ftrace_ret_stack **ret_stack_list;
6732 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
6733 sizeof(struct ftrace_ret_stack *),
6736 if (!ret_stack_list)
6739 /* The cpu_boot init_task->ret_stack will never be freed */
6740 for_each_online_cpu(cpu) {
6741 if (!idle_task(cpu)->ret_stack)
6742 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
6746 ret = alloc_retstack_tasklist(ret_stack_list);
6747 } while (ret == -EAGAIN);
6750 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6752 pr_info("ftrace_graph: Couldn't activate tracepoint"
6753 " probe to kernel_sched_switch\n");
6756 kfree(ret_stack_list);
6761 * Hibernation protection.
6762 * The state of the current task is too much unstable during
6763 * suspend/restore to disk. We want to protect against that.
6766 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
6770 case PM_HIBERNATION_PREPARE:
6771 pause_graph_tracing();
6774 case PM_POST_HIBERNATION:
6775 unpause_graph_tracing();
6781 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
6783 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
6785 return __ftrace_graph_entry(trace);
6789 * The function graph tracer should only trace the functions defined
6790 * by set_ftrace_filter and set_ftrace_notrace. If another function
6791 * tracer ops is registered, the graph tracer requires testing the
6792 * function against the global ops, and not just trace any function
6793 * that any ftrace_ops registered.
6795 static void update_function_graph_func(void)
6797 struct ftrace_ops *op;
6798 bool do_test = false;
6801 * The graph and global ops share the same set of functions
6802 * to test. If any other ops is on the list, then
6803 * the graph tracing needs to test if its the function
6806 do_for_each_ftrace_op(op, ftrace_ops_list) {
6807 if (op != &global_ops && op != &graph_ops &&
6808 op != &ftrace_list_end) {
6810 /* in double loop, break out with goto */
6813 } while_for_each_ftrace_op(op);
6816 ftrace_graph_entry = ftrace_graph_entry_test;
6818 ftrace_graph_entry = __ftrace_graph_entry;
6821 static struct notifier_block ftrace_suspend_notifier = {
6822 .notifier_call = ftrace_suspend_notifier_call,
6825 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
6826 trace_func_graph_ent_t entryfunc)
6830 mutex_lock(&ftrace_lock);
6832 /* we currently allow only one tracer registered at a time */
6833 if (ftrace_graph_active) {
6838 register_pm_notifier(&ftrace_suspend_notifier);
6840 ftrace_graph_active++;
6841 ret = start_graph_tracing();
6843 ftrace_graph_active--;
6847 ftrace_graph_return = retfunc;
6850 * Update the indirect function to the entryfunc, and the
6851 * function that gets called to the entry_test first. Then
6852 * call the update fgraph entry function to determine if
6853 * the entryfunc should be called directly or not.
6855 __ftrace_graph_entry = entryfunc;
6856 ftrace_graph_entry = ftrace_graph_entry_test;
6857 update_function_graph_func();
6859 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
6861 mutex_unlock(&ftrace_lock);
6865 void unregister_ftrace_graph(void)
6867 mutex_lock(&ftrace_lock);
6869 if (unlikely(!ftrace_graph_active))
6872 ftrace_graph_active--;
6873 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
6874 ftrace_graph_entry = ftrace_graph_entry_stub;
6875 __ftrace_graph_entry = ftrace_graph_entry_stub;
6876 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
6877 unregister_pm_notifier(&ftrace_suspend_notifier);
6878 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6881 mutex_unlock(&ftrace_lock);
6884 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
6887 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
6889 atomic_set(&t->trace_overrun, 0);
6890 t->ftrace_timestamp = 0;
6891 /* make curr_ret_stack visible before we add the ret_stack */
6893 t->ret_stack = ret_stack;
6897 * Allocate a return stack for the idle task. May be the first
6898 * time through, or it may be done by CPU hotplug online.
6900 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
6902 t->curr_ret_stack = -1;
6904 * The idle task has no parent, it either has its own
6905 * stack or no stack at all.
6908 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
6910 if (ftrace_graph_active) {
6911 struct ftrace_ret_stack *ret_stack;
6913 ret_stack = per_cpu(idle_ret_stack, cpu);
6915 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6916 * sizeof(struct ftrace_ret_stack),
6920 per_cpu(idle_ret_stack, cpu) = ret_stack;
6922 graph_init_task(t, ret_stack);
6926 /* Allocate a return stack for newly created task */
6927 void ftrace_graph_init_task(struct task_struct *t)
6929 /* Make sure we do not use the parent ret_stack */
6930 t->ret_stack = NULL;
6931 t->curr_ret_stack = -1;
6933 if (ftrace_graph_active) {
6934 struct ftrace_ret_stack *ret_stack;
6936 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6937 * sizeof(struct ftrace_ret_stack),
6941 graph_init_task(t, ret_stack);
6945 void ftrace_graph_exit_task(struct task_struct *t)
6947 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6949 t->ret_stack = NULL;
6950 /* NULL must become visible to IRQs before we free it: */