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/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/tracefs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
36 #include <trace/events/sched.h>
38 #include <asm/setup.h>
40 #include "trace_output.h"
41 #include "trace_stat.h"
43 #define FTRACE_WARN_ON(cond) \
51 #define FTRACE_WARN_ON_ONCE(cond) \
54 if (WARN_ON_ONCE(___r)) \
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
65 #ifdef CONFIG_DYNAMIC_FTRACE
66 #define INIT_OPS_HASH(opsname) \
67 .func_hash = &opsname.local_hash, \
68 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
69 #define ASSIGN_OPS_HASH(opsname, val) \
71 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
73 #define INIT_OPS_HASH(opsname)
74 #define ASSIGN_OPS_HASH(opsname, val)
77 static struct ftrace_ops ftrace_list_end __read_mostly = {
79 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
80 INIT_OPS_HASH(ftrace_list_end)
83 /* ftrace_enabled is a method to turn ftrace on or off */
84 int ftrace_enabled __read_mostly;
85 static int last_ftrace_enabled;
87 /* Current function tracing op */
88 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
89 /* What to set function_trace_op to */
90 static struct ftrace_ops *set_function_trace_op;
92 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
94 struct trace_array *tr;
96 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
101 return tr->function_pids != NULL;
104 static void ftrace_update_trampoline(struct ftrace_ops *ops);
107 * ftrace_disabled is set when an anomaly is discovered.
108 * ftrace_disabled is much stronger than ftrace_enabled.
110 static int ftrace_disabled __read_mostly;
112 static DEFINE_MUTEX(ftrace_lock);
114 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
115 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
116 static struct ftrace_ops global_ops;
118 #if ARCH_SUPPORTS_FTRACE_OPS
119 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
120 struct ftrace_ops *op, struct pt_regs *regs);
122 /* See comment below, where ftrace_ops_list_func is defined */
123 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
124 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
128 * Traverse the ftrace_global_list, invoking all entries. The reason that we
129 * can use rcu_dereference_raw_notrace() is that elements removed from this list
130 * are simply leaked, so there is no need to interact with a grace-period
131 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle
132 * concurrent insertions into the ftrace_global_list.
134 * Silly Alpha and silly pointer-speculation compiler optimizations!
136 #define do_for_each_ftrace_op(op, list) \
137 op = rcu_dereference_raw_notrace(list); \
141 * Optimized for just a single item in the list (as that is the normal case).
143 #define while_for_each_ftrace_op(op) \
144 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \
145 unlikely((op) != &ftrace_list_end))
147 static inline void ftrace_ops_init(struct ftrace_ops *ops)
149 #ifdef CONFIG_DYNAMIC_FTRACE
150 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
151 mutex_init(&ops->local_hash.regex_lock);
152 ops->func_hash = &ops->local_hash;
153 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
159 * ftrace_nr_registered_ops - return number of ops registered
161 * Returns the number of ftrace_ops registered and tracing functions
163 int ftrace_nr_registered_ops(void)
165 struct ftrace_ops *ops;
168 mutex_lock(&ftrace_lock);
170 for (ops = ftrace_ops_list;
171 ops != &ftrace_list_end; ops = ops->next)
174 mutex_unlock(&ftrace_lock);
179 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
180 struct ftrace_ops *op, struct pt_regs *regs)
182 struct trace_array *tr = op->private;
184 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
187 op->saved_func(ip, parent_ip, op, regs);
191 * clear_ftrace_function - reset the ftrace function
193 * This NULLs the ftrace function and in essence stops
194 * tracing. There may be lag
196 void clear_ftrace_function(void)
198 ftrace_trace_function = ftrace_stub;
201 static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
205 for_each_possible_cpu(cpu)
206 *per_cpu_ptr(ops->disabled, cpu) = 1;
209 static int per_cpu_ops_alloc(struct ftrace_ops *ops)
211 int __percpu *disabled;
213 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
216 disabled = alloc_percpu(int);
220 ops->disabled = disabled;
221 per_cpu_ops_disable_all(ops);
225 static void ftrace_sync(struct work_struct *work)
228 * This function is just a stub to implement a hard force
229 * of synchronize_sched(). This requires synchronizing
230 * tasks even in userspace and idle.
232 * Yes, function tracing is rude.
236 static void ftrace_sync_ipi(void *data)
238 /* Probably not needed, but do it anyway */
242 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
243 static void update_function_graph_func(void);
245 /* Both enabled by default (can be cleared by function_graph tracer flags */
246 static bool fgraph_sleep_time = true;
247 static bool fgraph_graph_time = true;
250 static inline void update_function_graph_func(void) { }
254 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
257 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
258 * then it needs to call the list anyway.
260 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
261 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
262 return ftrace_ops_list_func;
264 return ftrace_ops_get_func(ops);
267 static void update_ftrace_function(void)
272 * Prepare the ftrace_ops that the arch callback will use.
273 * If there's only one ftrace_ops registered, the ftrace_ops_list
274 * will point to the ops we want.
276 set_function_trace_op = ftrace_ops_list;
278 /* If there's no ftrace_ops registered, just call the stub function */
279 if (ftrace_ops_list == &ftrace_list_end) {
283 * If we are at the end of the list and this ops is
284 * recursion safe and not dynamic and the arch supports passing ops,
285 * then have the mcount trampoline call the function directly.
287 } else if (ftrace_ops_list->next == &ftrace_list_end) {
288 func = ftrace_ops_get_list_func(ftrace_ops_list);
291 /* Just use the default ftrace_ops */
292 set_function_trace_op = &ftrace_list_end;
293 func = ftrace_ops_list_func;
296 update_function_graph_func();
298 /* If there's no change, then do nothing more here */
299 if (ftrace_trace_function == func)
303 * If we are using the list function, it doesn't care
304 * about the function_trace_ops.
306 if (func == ftrace_ops_list_func) {
307 ftrace_trace_function = func;
309 * Don't even bother setting function_trace_ops,
310 * it would be racy to do so anyway.
315 #ifndef CONFIG_DYNAMIC_FTRACE
317 * For static tracing, we need to be a bit more careful.
318 * The function change takes affect immediately. Thus,
319 * we need to coorditate the setting of the function_trace_ops
320 * with the setting of the ftrace_trace_function.
322 * Set the function to the list ops, which will call the
323 * function we want, albeit indirectly, but it handles the
324 * ftrace_ops and doesn't depend on function_trace_op.
326 ftrace_trace_function = ftrace_ops_list_func;
328 * Make sure all CPUs see this. Yes this is slow, but static
329 * tracing is slow and nasty to have enabled.
331 schedule_on_each_cpu(ftrace_sync);
332 /* Now all cpus are using the list ops. */
333 function_trace_op = set_function_trace_op;
334 /* Make sure the function_trace_op is visible on all CPUs */
336 /* Nasty way to force a rmb on all cpus */
337 smp_call_function(ftrace_sync_ipi, NULL, 1);
338 /* OK, we are all set to update the ftrace_trace_function now! */
339 #endif /* !CONFIG_DYNAMIC_FTRACE */
341 ftrace_trace_function = func;
344 int using_ftrace_ops_list_func(void)
346 return ftrace_trace_function == ftrace_ops_list_func;
349 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
353 * We are entering ops into the list but another
354 * CPU might be walking that list. We need to make sure
355 * the ops->next pointer is valid before another CPU sees
356 * the ops pointer included into the list.
358 rcu_assign_pointer(*list, ops);
361 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
363 struct ftrace_ops **p;
366 * If we are removing the last function, then simply point
367 * to the ftrace_stub.
369 if (*list == ops && ops->next == &ftrace_list_end) {
370 *list = &ftrace_list_end;
374 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
385 static void ftrace_update_trampoline(struct ftrace_ops *ops);
387 static int __register_ftrace_function(struct ftrace_ops *ops)
389 if (ops->flags & FTRACE_OPS_FL_DELETED)
392 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
395 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
397 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
398 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
399 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
401 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
402 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
405 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
406 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
409 if (!core_kernel_data((unsigned long)ops))
410 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
412 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
413 if (per_cpu_ops_alloc(ops))
417 add_ftrace_ops(&ftrace_ops_list, ops);
419 /* Always save the function, and reset at unregistering */
420 ops->saved_func = ops->func;
422 if (ftrace_pids_enabled(ops))
423 ops->func = ftrace_pid_func;
425 ftrace_update_trampoline(ops);
428 update_ftrace_function();
433 static int __unregister_ftrace_function(struct ftrace_ops *ops)
437 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
440 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
446 update_ftrace_function();
448 ops->func = ops->saved_func;
453 static void ftrace_update_pid_func(void)
455 struct ftrace_ops *op;
457 /* Only do something if we are tracing something */
458 if (ftrace_trace_function == ftrace_stub)
461 do_for_each_ftrace_op(op, ftrace_ops_list) {
462 if (op->flags & FTRACE_OPS_FL_PID) {
463 op->func = ftrace_pids_enabled(op) ?
464 ftrace_pid_func : op->saved_func;
465 ftrace_update_trampoline(op);
467 } while_for_each_ftrace_op(op);
469 update_ftrace_function();
472 #ifdef CONFIG_FUNCTION_PROFILER
473 struct ftrace_profile {
474 struct hlist_node node;
476 unsigned long counter;
477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
478 unsigned long long time;
479 unsigned long long time_squared;
483 struct ftrace_profile_page {
484 struct ftrace_profile_page *next;
486 struct ftrace_profile records[];
489 struct ftrace_profile_stat {
491 struct hlist_head *hash;
492 struct ftrace_profile_page *pages;
493 struct ftrace_profile_page *start;
494 struct tracer_stat stat;
497 #define PROFILE_RECORDS_SIZE \
498 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
500 #define PROFILES_PER_PAGE \
501 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
503 static int ftrace_profile_enabled __read_mostly;
505 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
506 static DEFINE_MUTEX(ftrace_profile_lock);
508 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
510 #define FTRACE_PROFILE_HASH_BITS 10
511 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
514 function_stat_next(void *v, int idx)
516 struct ftrace_profile *rec = v;
517 struct ftrace_profile_page *pg;
519 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
525 if ((void *)rec >= (void *)&pg->records[pg->index]) {
529 rec = &pg->records[0];
537 static void *function_stat_start(struct tracer_stat *trace)
539 struct ftrace_profile_stat *stat =
540 container_of(trace, struct ftrace_profile_stat, stat);
542 if (!stat || !stat->start)
545 return function_stat_next(&stat->start->records[0], 0);
548 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
549 /* function graph compares on total time */
550 static int function_stat_cmp(void *p1, void *p2)
552 struct ftrace_profile *a = p1;
553 struct ftrace_profile *b = p2;
555 if (a->time < b->time)
557 if (a->time > b->time)
563 /* not function graph compares against hits */
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->counter < b->counter)
571 if (a->counter > b->counter)
578 static int function_stat_headers(struct seq_file *m)
580 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
581 seq_puts(m, " Function "
584 "--- ---- --- ---\n");
586 seq_puts(m, " Function Hit\n"
592 static int function_stat_show(struct seq_file *m, void *v)
594 struct ftrace_profile *rec = v;
595 char str[KSYM_SYMBOL_LEN];
597 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
598 static struct trace_seq s;
599 unsigned long long avg;
600 unsigned long long stddev;
602 mutex_lock(&ftrace_profile_lock);
604 /* we raced with function_profile_reset() */
605 if (unlikely(rec->counter == 0)) {
610 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
612 do_div(avg, rec->counter);
613 if (tracing_thresh && (avg < tracing_thresh))
617 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
618 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
620 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
623 /* Sample standard deviation (s^2) */
624 if (rec->counter <= 1)
628 * Apply Welford's method:
629 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
631 stddev = rec->counter * rec->time_squared -
632 rec->time * rec->time;
635 * Divide only 1000 for ns^2 -> us^2 conversion.
636 * trace_print_graph_duration will divide 1000 again.
638 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
642 trace_print_graph_duration(rec->time, &s);
643 trace_seq_puts(&s, " ");
644 trace_print_graph_duration(avg, &s);
645 trace_seq_puts(&s, " ");
646 trace_print_graph_duration(stddev, &s);
647 trace_print_seq(m, &s);
651 mutex_unlock(&ftrace_profile_lock);
656 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
658 struct ftrace_profile_page *pg;
660 pg = stat->pages = stat->start;
663 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
668 memset(stat->hash, 0,
669 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
672 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
674 struct ftrace_profile_page *pg;
679 /* If we already allocated, do nothing */
683 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
687 #ifdef CONFIG_DYNAMIC_FTRACE
688 functions = ftrace_update_tot_cnt;
691 * We do not know the number of functions that exist because
692 * dynamic tracing is what counts them. With past experience
693 * we have around 20K functions. That should be more than enough.
694 * It is highly unlikely we will execute every function in
700 pg = stat->start = stat->pages;
702 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
704 for (i = 1; i < pages; i++) {
705 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
716 unsigned long tmp = (unsigned long)pg;
728 static int ftrace_profile_init_cpu(int cpu)
730 struct ftrace_profile_stat *stat;
733 stat = &per_cpu(ftrace_profile_stats, cpu);
736 /* If the profile is already created, simply reset it */
737 ftrace_profile_reset(stat);
742 * We are profiling all functions, but usually only a few thousand
743 * functions are hit. We'll make a hash of 1024 items.
745 size = FTRACE_PROFILE_HASH_SIZE;
747 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
752 /* Preallocate the function profiling pages */
753 if (ftrace_profile_pages_init(stat) < 0) {
762 static int ftrace_profile_init(void)
767 for_each_possible_cpu(cpu) {
768 ret = ftrace_profile_init_cpu(cpu);
776 /* interrupts must be disabled */
777 static struct ftrace_profile *
778 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
780 struct ftrace_profile *rec;
781 struct hlist_head *hhd;
784 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
785 hhd = &stat->hash[key];
787 if (hlist_empty(hhd))
790 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
798 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
799 struct ftrace_profile *rec)
803 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
804 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
808 * The memory is already allocated, this simply finds a new record to use.
810 static struct ftrace_profile *
811 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
813 struct ftrace_profile *rec = NULL;
815 /* prevent recursion (from NMIs) */
816 if (atomic_inc_return(&stat->disabled) != 1)
820 * Try to find the function again since an NMI
821 * could have added it
823 rec = ftrace_find_profiled_func(stat, ip);
827 if (stat->pages->index == PROFILES_PER_PAGE) {
828 if (!stat->pages->next)
830 stat->pages = stat->pages->next;
833 rec = &stat->pages->records[stat->pages->index++];
835 ftrace_add_profile(stat, rec);
838 atomic_dec(&stat->disabled);
844 function_profile_call(unsigned long ip, unsigned long parent_ip,
845 struct ftrace_ops *ops, struct pt_regs *regs)
847 struct ftrace_profile_stat *stat;
848 struct ftrace_profile *rec;
851 if (!ftrace_profile_enabled)
854 local_irq_save(flags);
856 stat = this_cpu_ptr(&ftrace_profile_stats);
857 if (!stat->hash || !ftrace_profile_enabled)
860 rec = ftrace_find_profiled_func(stat, ip);
862 rec = ftrace_profile_alloc(stat, ip);
869 local_irq_restore(flags);
872 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
873 static int profile_graph_entry(struct ftrace_graph_ent *trace)
875 int index = trace->depth;
877 function_profile_call(trace->func, 0, NULL, NULL);
879 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
880 current->ret_stack[index].subtime = 0;
885 static void profile_graph_return(struct ftrace_graph_ret *trace)
887 struct ftrace_profile_stat *stat;
888 unsigned long long calltime;
889 struct ftrace_profile *rec;
892 local_irq_save(flags);
893 stat = this_cpu_ptr(&ftrace_profile_stats);
894 if (!stat->hash || !ftrace_profile_enabled)
897 /* If the calltime was zero'd ignore it */
898 if (!trace->calltime)
901 calltime = trace->rettime - trace->calltime;
903 if (!fgraph_graph_time) {
906 index = trace->depth;
908 /* Append this call time to the parent time to subtract */
910 current->ret_stack[index - 1].subtime += calltime;
912 if (current->ret_stack[index].subtime < calltime)
913 calltime -= current->ret_stack[index].subtime;
918 rec = ftrace_find_profiled_func(stat, trace->func);
920 rec->time += calltime;
921 rec->time_squared += calltime * calltime;
925 local_irq_restore(flags);
928 static int register_ftrace_profiler(void)
930 return register_ftrace_graph(&profile_graph_return,
931 &profile_graph_entry);
934 static void unregister_ftrace_profiler(void)
936 unregister_ftrace_graph();
939 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
940 .func = function_profile_call,
941 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
942 INIT_OPS_HASH(ftrace_profile_ops)
945 static int register_ftrace_profiler(void)
947 return register_ftrace_function(&ftrace_profile_ops);
950 static void unregister_ftrace_profiler(void)
952 unregister_ftrace_function(&ftrace_profile_ops);
954 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
957 ftrace_profile_write(struct file *filp, const char __user *ubuf,
958 size_t cnt, loff_t *ppos)
963 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
969 mutex_lock(&ftrace_profile_lock);
970 if (ftrace_profile_enabled ^ val) {
972 ret = ftrace_profile_init();
978 ret = register_ftrace_profiler();
983 ftrace_profile_enabled = 1;
985 ftrace_profile_enabled = 0;
987 * unregister_ftrace_profiler calls stop_machine
988 * so this acts like an synchronize_sched.
990 unregister_ftrace_profiler();
994 mutex_unlock(&ftrace_profile_lock);
1002 ftrace_profile_read(struct file *filp, char __user *ubuf,
1003 size_t cnt, loff_t *ppos)
1005 char buf[64]; /* big enough to hold a number */
1008 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1009 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1012 static const struct file_operations ftrace_profile_fops = {
1013 .open = tracing_open_generic,
1014 .read = ftrace_profile_read,
1015 .write = ftrace_profile_write,
1016 .llseek = default_llseek,
1019 /* used to initialize the real stat files */
1020 static struct tracer_stat function_stats __initdata = {
1021 .name = "functions",
1022 .stat_start = function_stat_start,
1023 .stat_next = function_stat_next,
1024 .stat_cmp = function_stat_cmp,
1025 .stat_headers = function_stat_headers,
1026 .stat_show = function_stat_show
1029 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1031 struct ftrace_profile_stat *stat;
1032 struct dentry *entry;
1037 for_each_possible_cpu(cpu) {
1038 stat = &per_cpu(ftrace_profile_stats, cpu);
1040 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1043 * The files created are permanent, if something happens
1044 * we still do not free memory.
1047 "Could not allocate stat file for cpu %d\n",
1051 stat->stat = function_stats;
1052 stat->stat.name = name;
1053 ret = register_stat_tracer(&stat->stat);
1056 "Could not register function stat for cpu %d\n",
1063 entry = tracefs_create_file("function_profile_enabled", 0644,
1064 d_tracer, NULL, &ftrace_profile_fops);
1066 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1069 #else /* CONFIG_FUNCTION_PROFILER */
1070 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1073 #endif /* CONFIG_FUNCTION_PROFILER */
1075 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1077 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1078 static int ftrace_graph_active;
1080 # define ftrace_graph_active 0
1083 #ifdef CONFIG_DYNAMIC_FTRACE
1085 static struct ftrace_ops *removed_ops;
1088 * Set when doing a global update, like enabling all recs or disabling them.
1089 * It is not set when just updating a single ftrace_ops.
1091 static bool update_all_ops;
1093 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1094 # error Dynamic ftrace depends on MCOUNT_RECORD
1097 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1099 struct ftrace_func_probe {
1100 struct hlist_node node;
1101 struct ftrace_probe_ops *ops;
1102 unsigned long flags;
1105 struct list_head free_list;
1108 struct ftrace_func_entry {
1109 struct hlist_node hlist;
1114 * We make these constant because no one should touch them,
1115 * but they are used as the default "empty hash", to avoid allocating
1116 * it all the time. These are in a read only section such that if
1117 * anyone does try to modify it, it will cause an exception.
1119 static const struct hlist_head empty_buckets[1];
1120 static const struct ftrace_hash empty_hash = {
1121 .buckets = (struct hlist_head *)empty_buckets,
1123 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1125 static struct ftrace_ops global_ops = {
1126 .func = ftrace_stub,
1127 .local_hash.notrace_hash = EMPTY_HASH,
1128 .local_hash.filter_hash = EMPTY_HASH,
1129 INIT_OPS_HASH(global_ops)
1130 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1131 FTRACE_OPS_FL_INITIALIZED |
1136 * This is used by __kernel_text_address() to return true if the
1137 * address is on a dynamically allocated trampoline that would
1138 * not return true for either core_kernel_text() or
1139 * is_module_text_address().
1141 bool is_ftrace_trampoline(unsigned long addr)
1143 struct ftrace_ops *op;
1147 * Some of the ops may be dynamically allocated,
1148 * they are freed after a synchronize_sched().
1150 preempt_disable_notrace();
1152 do_for_each_ftrace_op(op, ftrace_ops_list) {
1154 * This is to check for dynamically allocated trampolines.
1155 * Trampolines that are in kernel text will have
1156 * core_kernel_text() return true.
1158 if (op->trampoline && op->trampoline_size)
1159 if (addr >= op->trampoline &&
1160 addr < op->trampoline + op->trampoline_size) {
1164 } while_for_each_ftrace_op(op);
1167 preempt_enable_notrace();
1172 struct ftrace_page {
1173 struct ftrace_page *next;
1174 struct dyn_ftrace *records;
1179 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1180 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1182 /* estimate from running different kernels */
1183 #define NR_TO_INIT 10000
1185 static struct ftrace_page *ftrace_pages_start;
1186 static struct ftrace_page *ftrace_pages;
1188 static __always_inline unsigned long
1189 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1191 if (hash->size_bits > 0)
1192 return hash_long(ip, hash->size_bits);
1197 /* Only use this function if ftrace_hash_empty() has already been tested */
1198 static __always_inline struct ftrace_func_entry *
1199 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1202 struct ftrace_func_entry *entry;
1203 struct hlist_head *hhd;
1205 key = ftrace_hash_key(hash, ip);
1206 hhd = &hash->buckets[key];
1208 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1209 if (entry->ip == ip)
1216 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1217 * @hash: The hash to look at
1218 * @ip: The instruction pointer to test
1220 * Search a given @hash to see if a given instruction pointer (@ip)
1223 * Returns the entry that holds the @ip if found. NULL otherwise.
1225 struct ftrace_func_entry *
1226 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1228 if (ftrace_hash_empty(hash))
1231 return __ftrace_lookup_ip(hash, ip);
1234 static void __add_hash_entry(struct ftrace_hash *hash,
1235 struct ftrace_func_entry *entry)
1237 struct hlist_head *hhd;
1240 key = ftrace_hash_key(hash, entry->ip);
1241 hhd = &hash->buckets[key];
1242 hlist_add_head(&entry->hlist, hhd);
1246 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1248 struct ftrace_func_entry *entry;
1250 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1255 __add_hash_entry(hash, entry);
1261 free_hash_entry(struct ftrace_hash *hash,
1262 struct ftrace_func_entry *entry)
1264 hlist_del(&entry->hlist);
1270 remove_hash_entry(struct ftrace_hash *hash,
1271 struct ftrace_func_entry *entry)
1273 hlist_del(&entry->hlist);
1277 static void ftrace_hash_clear(struct ftrace_hash *hash)
1279 struct hlist_head *hhd;
1280 struct hlist_node *tn;
1281 struct ftrace_func_entry *entry;
1282 int size = 1 << hash->size_bits;
1288 for (i = 0; i < size; i++) {
1289 hhd = &hash->buckets[i];
1290 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1291 free_hash_entry(hash, entry);
1293 FTRACE_WARN_ON(hash->count);
1296 static void free_ftrace_hash(struct ftrace_hash *hash)
1298 if (!hash || hash == EMPTY_HASH)
1300 ftrace_hash_clear(hash);
1301 kfree(hash->buckets);
1305 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1307 struct ftrace_hash *hash;
1309 hash = container_of(rcu, struct ftrace_hash, rcu);
1310 free_ftrace_hash(hash);
1313 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1315 if (!hash || hash == EMPTY_HASH)
1317 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1320 void ftrace_free_filter(struct ftrace_ops *ops)
1322 ftrace_ops_init(ops);
1323 free_ftrace_hash(ops->func_hash->filter_hash);
1324 free_ftrace_hash(ops->func_hash->notrace_hash);
1327 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1329 struct ftrace_hash *hash;
1332 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1336 size = 1 << size_bits;
1337 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1339 if (!hash->buckets) {
1344 hash->size_bits = size_bits;
1349 static struct ftrace_hash *
1350 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1352 struct ftrace_func_entry *entry;
1353 struct ftrace_hash *new_hash;
1358 new_hash = alloc_ftrace_hash(size_bits);
1363 if (ftrace_hash_empty(hash))
1366 size = 1 << hash->size_bits;
1367 for (i = 0; i < size; i++) {
1368 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1369 ret = add_hash_entry(new_hash, entry->ip);
1375 FTRACE_WARN_ON(new_hash->count != hash->count);
1380 free_ftrace_hash(new_hash);
1385 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1387 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1389 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1390 struct ftrace_hash *new_hash);
1392 static struct ftrace_hash *
1393 __ftrace_hash_move(struct ftrace_hash *src)
1395 struct ftrace_func_entry *entry;
1396 struct hlist_node *tn;
1397 struct hlist_head *hhd;
1398 struct ftrace_hash *new_hash;
1399 int size = src->count;
1404 * If the new source is empty, just return the empty_hash.
1410 * Make the hash size about 1/2 the # found
1412 for (size /= 2; size; size >>= 1)
1415 /* Don't allocate too much */
1416 if (bits > FTRACE_HASH_MAX_BITS)
1417 bits = FTRACE_HASH_MAX_BITS;
1419 new_hash = alloc_ftrace_hash(bits);
1423 size = 1 << src->size_bits;
1424 for (i = 0; i < size; i++) {
1425 hhd = &src->buckets[i];
1426 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1427 remove_hash_entry(src, entry);
1428 __add_hash_entry(new_hash, entry);
1436 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1437 struct ftrace_hash **dst, struct ftrace_hash *src)
1439 struct ftrace_hash *new_hash;
1442 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1443 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1446 new_hash = __ftrace_hash_move(src);
1450 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1452 /* IPMODIFY should be updated only when filter_hash updating */
1453 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1455 free_ftrace_hash(new_hash);
1461 * Remove the current set, update the hash and add
1464 ftrace_hash_rec_disable_modify(ops, enable);
1466 rcu_assign_pointer(*dst, new_hash);
1468 ftrace_hash_rec_enable_modify(ops, enable);
1473 static bool hash_contains_ip(unsigned long ip,
1474 struct ftrace_ops_hash *hash)
1477 * The function record is a match if it exists in the filter
1478 * hash and not in the notrace hash. Note, an emty hash is
1479 * considered a match for the filter hash, but an empty
1480 * notrace hash is considered not in the notrace hash.
1482 return (ftrace_hash_empty(hash->filter_hash) ||
1483 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1484 (ftrace_hash_empty(hash->notrace_hash) ||
1485 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1489 * Test the hashes for this ops to see if we want to call
1490 * the ops->func or not.
1492 * It's a match if the ip is in the ops->filter_hash or
1493 * the filter_hash does not exist or is empty,
1495 * the ip is not in the ops->notrace_hash.
1497 * This needs to be called with preemption disabled as
1498 * the hashes are freed with call_rcu_sched().
1501 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1503 struct ftrace_ops_hash hash;
1506 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1508 * There's a small race when adding ops that the ftrace handler
1509 * that wants regs, may be called without them. We can not
1510 * allow that handler to be called if regs is NULL.
1512 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1516 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1517 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1519 if (hash_contains_ip(ip, &hash))
1528 * This is a double for. Do not use 'break' to break out of the loop,
1529 * you must use a goto.
1531 #define do_for_each_ftrace_rec(pg, rec) \
1532 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1534 for (_____i = 0; _____i < pg->index; _____i++) { \
1535 rec = &pg->records[_____i];
1537 #define while_for_each_ftrace_rec() \
1542 static int ftrace_cmp_recs(const void *a, const void *b)
1544 const struct dyn_ftrace *key = a;
1545 const struct dyn_ftrace *rec = b;
1547 if (key->flags < rec->ip)
1549 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1555 * ftrace_location_range - return the first address of a traced location
1556 * if it touches the given ip range
1557 * @start: start of range to search.
1558 * @end: end of range to search (inclusive). @end points to the last byte
1561 * Returns rec->ip if the related ftrace location is a least partly within
1562 * the given address range. That is, the first address of the instruction
1563 * that is either a NOP or call to the function tracer. It checks the ftrace
1564 * internal tables to determine if the address belongs or not.
1566 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1568 struct ftrace_page *pg;
1569 struct dyn_ftrace *rec;
1570 struct dyn_ftrace key;
1573 key.flags = end; /* overload flags, as it is unsigned long */
1575 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1576 if (end < pg->records[0].ip ||
1577 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1579 rec = bsearch(&key, pg->records, pg->index,
1580 sizeof(struct dyn_ftrace),
1590 * ftrace_location - return true if the ip giving is a traced location
1591 * @ip: the instruction pointer to check
1593 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1594 * That is, the instruction that is either a NOP or call to
1595 * the function tracer. It checks the ftrace internal tables to
1596 * determine if the address belongs or not.
1598 unsigned long ftrace_location(unsigned long ip)
1600 return ftrace_location_range(ip, ip);
1604 * ftrace_text_reserved - return true if range contains an ftrace location
1605 * @start: start of range to search
1606 * @end: end of range to search (inclusive). @end points to the last byte to check.
1608 * Returns 1 if @start and @end contains a ftrace location.
1609 * That is, the instruction that is either a NOP or call to
1610 * the function tracer. It checks the ftrace internal tables to
1611 * determine if the address belongs or not.
1613 int ftrace_text_reserved(const void *start, const void *end)
1617 ret = ftrace_location_range((unsigned long)start,
1618 (unsigned long)end);
1623 /* Test if ops registered to this rec needs regs */
1624 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1626 struct ftrace_ops *ops;
1627 bool keep_regs = false;
1629 for (ops = ftrace_ops_list;
1630 ops != &ftrace_list_end; ops = ops->next) {
1631 /* pass rec in as regs to have non-NULL val */
1632 if (ftrace_ops_test(ops, rec->ip, rec)) {
1633 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1643 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1647 struct ftrace_hash *hash;
1648 struct ftrace_hash *other_hash;
1649 struct ftrace_page *pg;
1650 struct dyn_ftrace *rec;
1651 bool update = false;
1655 /* Only update if the ops has been registered */
1656 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1660 * In the filter_hash case:
1661 * If the count is zero, we update all records.
1662 * Otherwise we just update the items in the hash.
1664 * In the notrace_hash case:
1665 * We enable the update in the hash.
1666 * As disabling notrace means enabling the tracing,
1667 * and enabling notrace means disabling, the inc variable
1671 hash = ops->func_hash->filter_hash;
1672 other_hash = ops->func_hash->notrace_hash;
1673 if (ftrace_hash_empty(hash))
1677 hash = ops->func_hash->notrace_hash;
1678 other_hash = ops->func_hash->filter_hash;
1680 * If the notrace hash has no items,
1681 * then there's nothing to do.
1683 if (ftrace_hash_empty(hash))
1687 do_for_each_ftrace_rec(pg, rec) {
1688 int in_other_hash = 0;
1692 if (rec->flags & FTRACE_FL_DISABLED)
1697 * Only the filter_hash affects all records.
1698 * Update if the record is not in the notrace hash.
1700 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1703 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1704 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1707 * If filter_hash is set, we want to match all functions
1708 * that are in the hash but not in the other hash.
1710 * If filter_hash is not set, then we are decrementing.
1711 * That means we match anything that is in the hash
1712 * and also in the other_hash. That is, we need to turn
1713 * off functions in the other hash because they are disabled
1716 if (filter_hash && in_hash && !in_other_hash)
1718 else if (!filter_hash && in_hash &&
1719 (in_other_hash || ftrace_hash_empty(other_hash)))
1727 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1731 * If there's only a single callback registered to a
1732 * function, and the ops has a trampoline registered
1733 * for it, then we can call it directly.
1735 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1736 rec->flags |= FTRACE_FL_TRAMP;
1739 * If we are adding another function callback
1740 * to this function, and the previous had a
1741 * custom trampoline in use, then we need to go
1742 * back to the default trampoline.
1744 rec->flags &= ~FTRACE_FL_TRAMP;
1747 * If any ops wants regs saved for this function
1748 * then all ops will get saved regs.
1750 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1751 rec->flags |= FTRACE_FL_REGS;
1753 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1758 * If the rec had REGS enabled and the ops that is
1759 * being removed had REGS set, then see if there is
1760 * still any ops for this record that wants regs.
1761 * If not, we can stop recording them.
1763 if (ftrace_rec_count(rec) > 0 &&
1764 rec->flags & FTRACE_FL_REGS &&
1765 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1766 if (!test_rec_ops_needs_regs(rec))
1767 rec->flags &= ~FTRACE_FL_REGS;
1771 * If the rec had TRAMP enabled, then it needs to
1772 * be cleared. As TRAMP can only be enabled iff
1773 * there is only a single ops attached to it.
1774 * In otherwords, always disable it on decrementing.
1775 * In the future, we may set it if rec count is
1776 * decremented to one, and the ops that is left
1779 rec->flags &= ~FTRACE_FL_TRAMP;
1782 * flags will be cleared in ftrace_check_record()
1783 * if rec count is zero.
1788 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1789 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1791 /* Shortcut, if we handled all records, we are done. */
1792 if (!all && count == hash->count)
1794 } while_for_each_ftrace_rec();
1799 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1802 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1805 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1808 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1811 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1812 int filter_hash, int inc)
1814 struct ftrace_ops *op;
1816 __ftrace_hash_rec_update(ops, filter_hash, inc);
1818 if (ops->func_hash != &global_ops.local_hash)
1822 * If the ops shares the global_ops hash, then we need to update
1823 * all ops that are enabled and use this hash.
1825 do_for_each_ftrace_op(op, ftrace_ops_list) {
1829 if (op->func_hash == &global_ops.local_hash)
1830 __ftrace_hash_rec_update(op, filter_hash, inc);
1831 } while_for_each_ftrace_op(op);
1834 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1837 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1840 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1843 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1847 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1848 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1849 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1850 * Note that old_hash and new_hash has below meanings
1851 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1852 * - If the hash is EMPTY_HASH, it hits nothing
1853 * - Anything else hits the recs which match the hash entries.
1855 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1856 struct ftrace_hash *old_hash,
1857 struct ftrace_hash *new_hash)
1859 struct ftrace_page *pg;
1860 struct dyn_ftrace *rec, *end = NULL;
1863 /* Only update if the ops has been registered */
1864 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1867 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1871 * Since the IPMODIFY is a very address sensitive action, we do not
1872 * allow ftrace_ops to set all functions to new hash.
1874 if (!new_hash || !old_hash)
1877 /* Update rec->flags */
1878 do_for_each_ftrace_rec(pg, rec) {
1880 if (rec->flags & FTRACE_FL_DISABLED)
1883 /* We need to update only differences of filter_hash */
1884 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1885 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1886 if (in_old == in_new)
1890 /* New entries must ensure no others are using it */
1891 if (rec->flags & FTRACE_FL_IPMODIFY)
1893 rec->flags |= FTRACE_FL_IPMODIFY;
1894 } else /* Removed entry */
1895 rec->flags &= ~FTRACE_FL_IPMODIFY;
1896 } while_for_each_ftrace_rec();
1903 /* Roll back what we did above */
1904 do_for_each_ftrace_rec(pg, rec) {
1906 if (rec->flags & FTRACE_FL_DISABLED)
1912 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1913 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1914 if (in_old == in_new)
1918 rec->flags &= ~FTRACE_FL_IPMODIFY;
1920 rec->flags |= FTRACE_FL_IPMODIFY;
1921 } while_for_each_ftrace_rec();
1927 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1929 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1931 if (ftrace_hash_empty(hash))
1934 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1937 /* Disabling always succeeds */
1938 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1940 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1942 if (ftrace_hash_empty(hash))
1945 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1948 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1949 struct ftrace_hash *new_hash)
1951 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1953 if (ftrace_hash_empty(old_hash))
1956 if (ftrace_hash_empty(new_hash))
1959 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1962 static void print_ip_ins(const char *fmt, const unsigned char *p)
1966 printk(KERN_CONT "%s", fmt);
1968 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1969 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1972 static struct ftrace_ops *
1973 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1974 static struct ftrace_ops *
1975 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1977 enum ftrace_bug_type ftrace_bug_type;
1978 const void *ftrace_expected;
1980 static void print_bug_type(void)
1982 switch (ftrace_bug_type) {
1983 case FTRACE_BUG_UNKNOWN:
1985 case FTRACE_BUG_INIT:
1986 pr_info("Initializing ftrace call sites\n");
1988 case FTRACE_BUG_NOP:
1989 pr_info("Setting ftrace call site to NOP\n");
1991 case FTRACE_BUG_CALL:
1992 pr_info("Setting ftrace call site to call ftrace function\n");
1994 case FTRACE_BUG_UPDATE:
1995 pr_info("Updating ftrace call site to call a different ftrace function\n");
2001 * ftrace_bug - report and shutdown function tracer
2002 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2003 * @rec: The record that failed
2005 * The arch code that enables or disables the function tracing
2006 * can call ftrace_bug() when it has detected a problem in
2007 * modifying the code. @failed should be one of either:
2008 * EFAULT - if the problem happens on reading the @ip address
2009 * EINVAL - if what is read at @ip is not what was expected
2010 * EPERM - if the problem happens on writting to the @ip address
2012 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2014 unsigned long ip = rec ? rec->ip : 0;
2018 FTRACE_WARN_ON_ONCE(1);
2019 pr_info("ftrace faulted on modifying ");
2023 FTRACE_WARN_ON_ONCE(1);
2024 pr_info("ftrace failed to modify ");
2026 print_ip_ins(" actual: ", (unsigned char *)ip);
2028 if (ftrace_expected) {
2029 print_ip_ins(" expected: ", ftrace_expected);
2034 FTRACE_WARN_ON_ONCE(1);
2035 pr_info("ftrace faulted on writing ");
2039 FTRACE_WARN_ON_ONCE(1);
2040 pr_info("ftrace faulted on unknown error ");
2045 struct ftrace_ops *ops = NULL;
2047 pr_info("ftrace record flags: %lx\n", rec->flags);
2048 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2049 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2050 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2051 ops = ftrace_find_tramp_ops_any(rec);
2054 pr_cont("\ttramp: %pS (%pS)",
2055 (void *)ops->trampoline,
2057 ops = ftrace_find_tramp_ops_next(rec, ops);
2060 pr_cont("\ttramp: ERROR!");
2063 ip = ftrace_get_addr_curr(rec);
2064 pr_cont("\n expected tramp: %lx\n", ip);
2068 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2070 unsigned long flag = 0UL;
2072 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2074 if (rec->flags & FTRACE_FL_DISABLED)
2075 return FTRACE_UPDATE_IGNORE;
2078 * If we are updating calls:
2080 * If the record has a ref count, then we need to enable it
2081 * because someone is using it.
2083 * Otherwise we make sure its disabled.
2085 * If we are disabling calls, then disable all records that
2088 if (enable && ftrace_rec_count(rec))
2089 flag = FTRACE_FL_ENABLED;
2092 * If enabling and the REGS flag does not match the REGS_EN, or
2093 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2094 * this record. Set flags to fail the compare against ENABLED.
2097 if (!(rec->flags & FTRACE_FL_REGS) !=
2098 !(rec->flags & FTRACE_FL_REGS_EN))
2099 flag |= FTRACE_FL_REGS;
2101 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2102 !(rec->flags & FTRACE_FL_TRAMP_EN))
2103 flag |= FTRACE_FL_TRAMP;
2106 /* If the state of this record hasn't changed, then do nothing */
2107 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2108 return FTRACE_UPDATE_IGNORE;
2111 /* Save off if rec is being enabled (for return value) */
2112 flag ^= rec->flags & FTRACE_FL_ENABLED;
2115 rec->flags |= FTRACE_FL_ENABLED;
2116 if (flag & FTRACE_FL_REGS) {
2117 if (rec->flags & FTRACE_FL_REGS)
2118 rec->flags |= FTRACE_FL_REGS_EN;
2120 rec->flags &= ~FTRACE_FL_REGS_EN;
2122 if (flag & FTRACE_FL_TRAMP) {
2123 if (rec->flags & FTRACE_FL_TRAMP)
2124 rec->flags |= FTRACE_FL_TRAMP_EN;
2126 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2131 * If this record is being updated from a nop, then
2132 * return UPDATE_MAKE_CALL.
2134 * return UPDATE_MODIFY_CALL to tell the caller to convert
2135 * from the save regs, to a non-save regs function or
2136 * vice versa, or from a trampoline call.
2138 if (flag & FTRACE_FL_ENABLED) {
2139 ftrace_bug_type = FTRACE_BUG_CALL;
2140 return FTRACE_UPDATE_MAKE_CALL;
2143 ftrace_bug_type = FTRACE_BUG_UPDATE;
2144 return FTRACE_UPDATE_MODIFY_CALL;
2148 /* If there's no more users, clear all flags */
2149 if (!ftrace_rec_count(rec))
2153 * Just disable the record, but keep the ops TRAMP
2154 * and REGS states. The _EN flags must be disabled though.
2156 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2160 ftrace_bug_type = FTRACE_BUG_NOP;
2161 return FTRACE_UPDATE_MAKE_NOP;
2165 * ftrace_update_record, set a record that now is tracing or not
2166 * @rec: the record to update
2167 * @enable: set to 1 if the record is tracing, zero to force disable
2169 * The records that represent all functions that can be traced need
2170 * to be updated when tracing has been enabled.
2172 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2174 return ftrace_check_record(rec, enable, 1);
2178 * ftrace_test_record, check if the record has been enabled or not
2179 * @rec: the record to test
2180 * @enable: set to 1 to check if enabled, 0 if it is disabled
2182 * The arch code may need to test if a record is already set to
2183 * tracing to determine how to modify the function code that it
2186 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2188 return ftrace_check_record(rec, enable, 0);
2191 static struct ftrace_ops *
2192 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2194 struct ftrace_ops *op;
2195 unsigned long ip = rec->ip;
2197 do_for_each_ftrace_op(op, ftrace_ops_list) {
2199 if (!op->trampoline)
2202 if (hash_contains_ip(ip, op->func_hash))
2204 } while_for_each_ftrace_op(op);
2209 static struct ftrace_ops *
2210 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2211 struct ftrace_ops *op)
2213 unsigned long ip = rec->ip;
2215 while_for_each_ftrace_op(op) {
2217 if (!op->trampoline)
2220 if (hash_contains_ip(ip, op->func_hash))
2227 static struct ftrace_ops *
2228 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2230 struct ftrace_ops *op;
2231 unsigned long ip = rec->ip;
2234 * Need to check removed ops first.
2235 * If they are being removed, and this rec has a tramp,
2236 * and this rec is in the ops list, then it would be the
2237 * one with the tramp.
2240 if (hash_contains_ip(ip, &removed_ops->old_hash))
2245 * Need to find the current trampoline for a rec.
2246 * Now, a trampoline is only attached to a rec if there
2247 * was a single 'ops' attached to it. But this can be called
2248 * when we are adding another op to the rec or removing the
2249 * current one. Thus, if the op is being added, we can
2250 * ignore it because it hasn't attached itself to the rec
2253 * If an ops is being modified (hooking to different functions)
2254 * then we don't care about the new functions that are being
2255 * added, just the old ones (that are probably being removed).
2257 * If we are adding an ops to a function that already is using
2258 * a trampoline, it needs to be removed (trampolines are only
2259 * for single ops connected), then an ops that is not being
2260 * modified also needs to be checked.
2262 do_for_each_ftrace_op(op, ftrace_ops_list) {
2264 if (!op->trampoline)
2268 * If the ops is being added, it hasn't gotten to
2269 * the point to be removed from this tree yet.
2271 if (op->flags & FTRACE_OPS_FL_ADDING)
2276 * If the ops is being modified and is in the old
2277 * hash, then it is probably being removed from this
2280 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2281 hash_contains_ip(ip, &op->old_hash))
2284 * If the ops is not being added or modified, and it's
2285 * in its normal filter hash, then this must be the one
2288 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2289 hash_contains_ip(ip, op->func_hash))
2292 } while_for_each_ftrace_op(op);
2297 static struct ftrace_ops *
2298 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2300 struct ftrace_ops *op;
2301 unsigned long ip = rec->ip;
2303 do_for_each_ftrace_op(op, ftrace_ops_list) {
2304 /* pass rec in as regs to have non-NULL val */
2305 if (hash_contains_ip(ip, op->func_hash))
2307 } while_for_each_ftrace_op(op);
2313 * ftrace_get_addr_new - Get the call address to set to
2314 * @rec: The ftrace record descriptor
2316 * If the record has the FTRACE_FL_REGS set, that means that it
2317 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2318 * is not not set, then it wants to convert to the normal callback.
2320 * Returns the address of the trampoline to set to
2322 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2324 struct ftrace_ops *ops;
2326 /* Trampolines take precedence over regs */
2327 if (rec->flags & FTRACE_FL_TRAMP) {
2328 ops = ftrace_find_tramp_ops_new(rec);
2329 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2330 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2331 (void *)rec->ip, (void *)rec->ip, rec->flags);
2332 /* Ftrace is shutting down, return anything */
2333 return (unsigned long)FTRACE_ADDR;
2335 return ops->trampoline;
2338 if (rec->flags & FTRACE_FL_REGS)
2339 return (unsigned long)FTRACE_REGS_ADDR;
2341 return (unsigned long)FTRACE_ADDR;
2345 * ftrace_get_addr_curr - Get the call address that is already there
2346 * @rec: The ftrace record descriptor
2348 * The FTRACE_FL_REGS_EN is set when the record already points to
2349 * a function that saves all the regs. Basically the '_EN' version
2350 * represents the current state of the function.
2352 * Returns the address of the trampoline that is currently being called
2354 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2356 struct ftrace_ops *ops;
2358 /* Trampolines take precedence over regs */
2359 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2360 ops = ftrace_find_tramp_ops_curr(rec);
2361 if (FTRACE_WARN_ON(!ops)) {
2362 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2363 (void *)rec->ip, (void *)rec->ip);
2364 /* Ftrace is shutting down, return anything */
2365 return (unsigned long)FTRACE_ADDR;
2367 return ops->trampoline;
2370 if (rec->flags & FTRACE_FL_REGS_EN)
2371 return (unsigned long)FTRACE_REGS_ADDR;
2373 return (unsigned long)FTRACE_ADDR;
2377 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2379 unsigned long ftrace_old_addr;
2380 unsigned long ftrace_addr;
2383 ftrace_addr = ftrace_get_addr_new(rec);
2385 /* This needs to be done before we call ftrace_update_record */
2386 ftrace_old_addr = ftrace_get_addr_curr(rec);
2388 ret = ftrace_update_record(rec, enable);
2390 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2393 case FTRACE_UPDATE_IGNORE:
2396 case FTRACE_UPDATE_MAKE_CALL:
2397 ftrace_bug_type = FTRACE_BUG_CALL;
2398 return ftrace_make_call(rec, ftrace_addr);
2400 case FTRACE_UPDATE_MAKE_NOP:
2401 ftrace_bug_type = FTRACE_BUG_NOP;
2402 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2404 case FTRACE_UPDATE_MODIFY_CALL:
2405 ftrace_bug_type = FTRACE_BUG_UPDATE;
2406 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2409 return -1; /* unknow ftrace bug */
2412 void __weak ftrace_replace_code(int enable)
2414 struct dyn_ftrace *rec;
2415 struct ftrace_page *pg;
2418 if (unlikely(ftrace_disabled))
2421 do_for_each_ftrace_rec(pg, rec) {
2423 if (rec->flags & FTRACE_FL_DISABLED)
2426 failed = __ftrace_replace_code(rec, enable);
2428 ftrace_bug(failed, rec);
2429 /* Stop processing */
2432 } while_for_each_ftrace_rec();
2435 struct ftrace_rec_iter {
2436 struct ftrace_page *pg;
2441 * ftrace_rec_iter_start, start up iterating over traced functions
2443 * Returns an iterator handle that is used to iterate over all
2444 * the records that represent address locations where functions
2447 * May return NULL if no records are available.
2449 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2452 * We only use a single iterator.
2453 * Protected by the ftrace_lock mutex.
2455 static struct ftrace_rec_iter ftrace_rec_iter;
2456 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2458 iter->pg = ftrace_pages_start;
2461 /* Could have empty pages */
2462 while (iter->pg && !iter->pg->index)
2463 iter->pg = iter->pg->next;
2472 * ftrace_rec_iter_next, get the next record to process.
2473 * @iter: The handle to the iterator.
2475 * Returns the next iterator after the given iterator @iter.
2477 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2481 if (iter->index >= iter->pg->index) {
2482 iter->pg = iter->pg->next;
2485 /* Could have empty pages */
2486 while (iter->pg && !iter->pg->index)
2487 iter->pg = iter->pg->next;
2497 * ftrace_rec_iter_record, get the record at the iterator location
2498 * @iter: The current iterator location
2500 * Returns the record that the current @iter is at.
2502 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2504 return &iter->pg->records[iter->index];
2508 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2512 if (unlikely(ftrace_disabled))
2515 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2517 ftrace_bug_type = FTRACE_BUG_INIT;
2518 ftrace_bug(ret, rec);
2525 * archs can override this function if they must do something
2526 * before the modifying code is performed.
2528 int __weak ftrace_arch_code_modify_prepare(void)
2534 * archs can override this function if they must do something
2535 * after the modifying code is performed.
2537 int __weak ftrace_arch_code_modify_post_process(void)
2542 void ftrace_modify_all_code(int command)
2544 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2548 * If the ftrace_caller calls a ftrace_ops func directly,
2549 * we need to make sure that it only traces functions it
2550 * expects to trace. When doing the switch of functions,
2551 * we need to update to the ftrace_ops_list_func first
2552 * before the transition between old and new calls are set,
2553 * as the ftrace_ops_list_func will check the ops hashes
2554 * to make sure the ops are having the right functions
2558 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2559 if (FTRACE_WARN_ON(err))
2563 if (command & FTRACE_UPDATE_CALLS)
2564 ftrace_replace_code(1);
2565 else if (command & FTRACE_DISABLE_CALLS)
2566 ftrace_replace_code(0);
2568 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2569 function_trace_op = set_function_trace_op;
2571 /* If irqs are disabled, we are in stop machine */
2572 if (!irqs_disabled())
2573 smp_call_function(ftrace_sync_ipi, NULL, 1);
2574 err = ftrace_update_ftrace_func(ftrace_trace_function);
2575 if (FTRACE_WARN_ON(err))
2579 if (command & FTRACE_START_FUNC_RET)
2580 err = ftrace_enable_ftrace_graph_caller();
2581 else if (command & FTRACE_STOP_FUNC_RET)
2582 err = ftrace_disable_ftrace_graph_caller();
2583 FTRACE_WARN_ON(err);
2586 static int __ftrace_modify_code(void *data)
2588 int *command = data;
2590 ftrace_modify_all_code(*command);
2596 * ftrace_run_stop_machine, go back to the stop machine method
2597 * @command: The command to tell ftrace what to do
2599 * If an arch needs to fall back to the stop machine method, the
2600 * it can call this function.
2602 void ftrace_run_stop_machine(int command)
2604 stop_machine(__ftrace_modify_code, &command, NULL);
2608 * arch_ftrace_update_code, modify the code to trace or not trace
2609 * @command: The command that needs to be done
2611 * Archs can override this function if it does not need to
2612 * run stop_machine() to modify code.
2614 void __weak arch_ftrace_update_code(int command)
2616 ftrace_run_stop_machine(command);
2619 static void ftrace_run_update_code(int command)
2623 ret = ftrace_arch_code_modify_prepare();
2624 FTRACE_WARN_ON(ret);
2629 * By default we use stop_machine() to modify the code.
2630 * But archs can do what ever they want as long as it
2631 * is safe. The stop_machine() is the safest, but also
2632 * produces the most overhead.
2634 arch_ftrace_update_code(command);
2636 ret = ftrace_arch_code_modify_post_process();
2637 FTRACE_WARN_ON(ret);
2640 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2641 struct ftrace_ops_hash *old_hash)
2643 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2644 ops->old_hash.filter_hash = old_hash->filter_hash;
2645 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2646 ftrace_run_update_code(command);
2647 ops->old_hash.filter_hash = NULL;
2648 ops->old_hash.notrace_hash = NULL;
2649 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2652 static ftrace_func_t saved_ftrace_func;
2653 static int ftrace_start_up;
2655 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2659 static void per_cpu_ops_free(struct ftrace_ops *ops)
2661 free_percpu(ops->disabled);
2664 static void ftrace_startup_enable(int command)
2666 if (saved_ftrace_func != ftrace_trace_function) {
2667 saved_ftrace_func = ftrace_trace_function;
2668 command |= FTRACE_UPDATE_TRACE_FUNC;
2671 if (!command || !ftrace_enabled)
2674 ftrace_run_update_code(command);
2677 static void ftrace_startup_all(int command)
2679 update_all_ops = true;
2680 ftrace_startup_enable(command);
2681 update_all_ops = false;
2684 static int ftrace_startup(struct ftrace_ops *ops, int command)
2688 if (unlikely(ftrace_disabled))
2691 ret = __register_ftrace_function(ops);
2698 * Note that ftrace probes uses this to start up
2699 * and modify functions it will probe. But we still
2700 * set the ADDING flag for modification, as probes
2701 * do not have trampolines. If they add them in the
2702 * future, then the probes will need to distinguish
2703 * between adding and updating probes.
2705 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2707 ret = ftrace_hash_ipmodify_enable(ops);
2709 /* Rollback registration process */
2710 __unregister_ftrace_function(ops);
2712 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2716 if (ftrace_hash_rec_enable(ops, 1))
2717 command |= FTRACE_UPDATE_CALLS;
2719 ftrace_startup_enable(command);
2721 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2726 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2730 if (unlikely(ftrace_disabled))
2733 ret = __unregister_ftrace_function(ops);
2739 * Just warn in case of unbalance, no need to kill ftrace, it's not
2740 * critical but the ftrace_call callers may be never nopped again after
2741 * further ftrace uses.
2743 WARN_ON_ONCE(ftrace_start_up < 0);
2745 /* Disabling ipmodify never fails */
2746 ftrace_hash_ipmodify_disable(ops);
2748 if (ftrace_hash_rec_disable(ops, 1))
2749 command |= FTRACE_UPDATE_CALLS;
2751 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2753 if (saved_ftrace_func != ftrace_trace_function) {
2754 saved_ftrace_func = ftrace_trace_function;
2755 command |= FTRACE_UPDATE_TRACE_FUNC;
2758 if (!command || !ftrace_enabled) {
2760 * If these are per_cpu ops, they still need their
2761 * per_cpu field freed. Since, function tracing is
2762 * not currently active, we can just free them
2763 * without synchronizing all CPUs.
2765 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2766 per_cpu_ops_free(ops);
2771 * If the ops uses a trampoline, then it needs to be
2772 * tested first on update.
2774 ops->flags |= FTRACE_OPS_FL_REMOVING;
2777 /* The trampoline logic checks the old hashes */
2778 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2779 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2781 ftrace_run_update_code(command);
2784 * If there's no more ops registered with ftrace, run a
2785 * sanity check to make sure all rec flags are cleared.
2787 if (ftrace_ops_list == &ftrace_list_end) {
2788 struct ftrace_page *pg;
2789 struct dyn_ftrace *rec;
2791 do_for_each_ftrace_rec(pg, rec) {
2792 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2793 pr_warn(" %pS flags:%lx\n",
2794 (void *)rec->ip, rec->flags);
2795 } while_for_each_ftrace_rec();
2798 ops->old_hash.filter_hash = NULL;
2799 ops->old_hash.notrace_hash = NULL;
2802 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2805 * Dynamic ops may be freed, we must make sure that all
2806 * callers are done before leaving this function.
2807 * The same goes for freeing the per_cpu data of the per_cpu
2810 * Again, normal synchronize_sched() is not good enough.
2811 * We need to do a hard force of sched synchronization.
2812 * This is because we use preempt_disable() to do RCU, but
2813 * the function tracers can be called where RCU is not watching
2814 * (like before user_exit()). We can not rely on the RCU
2815 * infrastructure to do the synchronization, thus we must do it
2818 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2819 schedule_on_each_cpu(ftrace_sync);
2821 arch_ftrace_trampoline_free(ops);
2823 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2824 per_cpu_ops_free(ops);
2830 static void ftrace_startup_sysctl(void)
2834 if (unlikely(ftrace_disabled))
2837 /* Force update next time */
2838 saved_ftrace_func = NULL;
2839 /* ftrace_start_up is true if we want ftrace running */
2840 if (ftrace_start_up) {
2841 command = FTRACE_UPDATE_CALLS;
2842 if (ftrace_graph_active)
2843 command |= FTRACE_START_FUNC_RET;
2844 ftrace_startup_enable(command);
2848 static void ftrace_shutdown_sysctl(void)
2852 if (unlikely(ftrace_disabled))
2855 /* ftrace_start_up is true if ftrace is running */
2856 if (ftrace_start_up) {
2857 command = FTRACE_DISABLE_CALLS;
2858 if (ftrace_graph_active)
2859 command |= FTRACE_STOP_FUNC_RET;
2860 ftrace_run_update_code(command);
2864 static u64 ftrace_update_time;
2865 unsigned long ftrace_update_tot_cnt;
2867 static inline int ops_traces_mod(struct ftrace_ops *ops)
2870 * Filter_hash being empty will default to trace module.
2871 * But notrace hash requires a test of individual module functions.
2873 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2874 ftrace_hash_empty(ops->func_hash->notrace_hash);
2878 * Check if the current ops references the record.
2880 * If the ops traces all functions, then it was already accounted for.
2881 * If the ops does not trace the current record function, skip it.
2882 * If the ops ignores the function via notrace filter, skip it.
2885 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2887 /* If ops isn't enabled, ignore it */
2888 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2891 /* If ops traces all then it includes this function */
2892 if (ops_traces_mod(ops))
2895 /* The function must be in the filter */
2896 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2897 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2900 /* If in notrace hash, we ignore it too */
2901 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2907 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2909 struct ftrace_page *pg;
2910 struct dyn_ftrace *p;
2912 unsigned long update_cnt = 0;
2913 unsigned long rec_flags = 0;
2916 start = ftrace_now(raw_smp_processor_id());
2919 * When a module is loaded, this function is called to convert
2920 * the calls to mcount in its text to nops, and also to create
2921 * an entry in the ftrace data. Now, if ftrace is activated
2922 * after this call, but before the module sets its text to
2923 * read-only, the modification of enabling ftrace can fail if
2924 * the read-only is done while ftrace is converting the calls.
2925 * To prevent this, the module's records are set as disabled
2926 * and will be enabled after the call to set the module's text
2930 rec_flags |= FTRACE_FL_DISABLED;
2932 for (pg = new_pgs; pg; pg = pg->next) {
2934 for (i = 0; i < pg->index; i++) {
2936 /* If something went wrong, bail without enabling anything */
2937 if (unlikely(ftrace_disabled))
2940 p = &pg->records[i];
2941 p->flags = rec_flags;
2944 * Do the initial record conversion from mcount jump
2945 * to the NOP instructions.
2947 if (!ftrace_code_disable(mod, p))
2954 stop = ftrace_now(raw_smp_processor_id());
2955 ftrace_update_time = stop - start;
2956 ftrace_update_tot_cnt += update_cnt;
2961 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2966 if (WARN_ON(!count))
2969 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2972 * We want to fill as much as possible. No more than a page
2975 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2979 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2982 /* if we can't allocate this size, try something smaller */
2989 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2998 static struct ftrace_page *
2999 ftrace_allocate_pages(unsigned long num_to_init)
3001 struct ftrace_page *start_pg;
3002 struct ftrace_page *pg;
3009 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3014 * Try to allocate as much as possible in one continues
3015 * location that fills in all of the space. We want to
3016 * waste as little space as possible.
3019 cnt = ftrace_allocate_records(pg, num_to_init);
3027 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3039 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3040 free_pages((unsigned long)pg->records, order);
3041 start_pg = pg->next;
3045 pr_info("ftrace: FAILED to allocate memory for functions\n");
3049 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3051 struct ftrace_iterator {
3054 struct ftrace_page *pg;
3055 struct dyn_ftrace *func;
3056 struct ftrace_func_probe *probe;
3057 struct trace_parser parser;
3058 struct ftrace_hash *hash;
3059 struct ftrace_ops *ops;
3066 t_hash_next(struct seq_file *m, loff_t *pos)
3068 struct ftrace_iterator *iter = m->private;
3069 struct hlist_node *hnd = NULL;
3070 struct hlist_head *hhd;
3076 hnd = &iter->probe->node;
3078 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3081 hhd = &ftrace_func_hash[iter->hidx];
3083 if (hlist_empty(hhd)) {
3099 if (WARN_ON_ONCE(!hnd))
3102 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3107 static void *t_hash_start(struct seq_file *m, loff_t *pos)
3109 struct ftrace_iterator *iter = m->private;
3113 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3116 if (iter->func_pos > *pos)
3120 for (l = 0; l <= (*pos - iter->func_pos); ) {
3121 p = t_hash_next(m, &l);
3128 /* Only set this if we have an item */
3129 iter->flags |= FTRACE_ITER_HASH;
3135 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3137 struct ftrace_func_probe *rec;
3140 if (WARN_ON_ONCE(!rec))
3143 if (rec->ops->print)
3144 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3146 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3149 seq_printf(m, ":%p", rec->data);
3156 t_next(struct seq_file *m, void *v, loff_t *pos)
3158 struct ftrace_iterator *iter = m->private;
3159 struct ftrace_ops *ops = iter->ops;
3160 struct dyn_ftrace *rec = NULL;
3162 if (unlikely(ftrace_disabled))
3165 if (iter->flags & FTRACE_ITER_HASH)
3166 return t_hash_next(m, pos);
3169 iter->pos = iter->func_pos = *pos;
3171 if (iter->flags & FTRACE_ITER_PRINTALL)
3172 return t_hash_start(m, pos);
3175 if (iter->idx >= iter->pg->index) {
3176 if (iter->pg->next) {
3177 iter->pg = iter->pg->next;
3182 rec = &iter->pg->records[iter->idx++];
3183 if (((iter->flags & FTRACE_ITER_FILTER) &&
3184 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3186 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3187 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3189 ((iter->flags & FTRACE_ITER_ENABLED) &&
3190 !(rec->flags & FTRACE_FL_ENABLED))) {
3198 return t_hash_start(m, pos);
3205 static void reset_iter_read(struct ftrace_iterator *iter)
3209 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3212 static void *t_start(struct seq_file *m, loff_t *pos)
3214 struct ftrace_iterator *iter = m->private;
3215 struct ftrace_ops *ops = iter->ops;
3219 mutex_lock(&ftrace_lock);
3221 if (unlikely(ftrace_disabled))
3225 * If an lseek was done, then reset and start from beginning.
3227 if (*pos < iter->pos)
3228 reset_iter_read(iter);
3231 * For set_ftrace_filter reading, if we have the filter
3232 * off, we can short cut and just print out that all
3233 * functions are enabled.
3235 if ((iter->flags & FTRACE_ITER_FILTER &&
3236 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3237 (iter->flags & FTRACE_ITER_NOTRACE &&
3238 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3240 return t_hash_start(m, pos);
3241 iter->flags |= FTRACE_ITER_PRINTALL;
3242 /* reset in case of seek/pread */
3243 iter->flags &= ~FTRACE_ITER_HASH;
3247 if (iter->flags & FTRACE_ITER_HASH)
3248 return t_hash_start(m, pos);
3251 * Unfortunately, we need to restart at ftrace_pages_start
3252 * every time we let go of the ftrace_mutex. This is because
3253 * those pointers can change without the lock.
3255 iter->pg = ftrace_pages_start;
3257 for (l = 0; l <= *pos; ) {
3258 p = t_next(m, p, &l);
3264 return t_hash_start(m, pos);
3269 static void t_stop(struct seq_file *m, void *p)
3271 mutex_unlock(&ftrace_lock);
3275 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3280 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3281 struct dyn_ftrace *rec)
3285 ptr = arch_ftrace_trampoline_func(ops, rec);
3287 seq_printf(m, " ->%pS", ptr);
3290 static int t_show(struct seq_file *m, void *v)
3292 struct ftrace_iterator *iter = m->private;
3293 struct dyn_ftrace *rec;
3295 if (iter->flags & FTRACE_ITER_HASH)
3296 return t_hash_show(m, iter);
3298 if (iter->flags & FTRACE_ITER_PRINTALL) {
3299 if (iter->flags & FTRACE_ITER_NOTRACE)
3300 seq_puts(m, "#### no functions disabled ####\n");
3302 seq_puts(m, "#### all functions enabled ####\n");
3311 seq_printf(m, "%ps", (void *)rec->ip);
3312 if (iter->flags & FTRACE_ITER_ENABLED) {
3313 struct ftrace_ops *ops;
3315 seq_printf(m, " (%ld)%s%s",
3316 ftrace_rec_count(rec),
3317 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3318 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3319 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3320 ops = ftrace_find_tramp_ops_any(rec);
3323 seq_printf(m, "\ttramp: %pS (%pS)",
3324 (void *)ops->trampoline,
3326 add_trampoline_func(m, ops, rec);
3327 ops = ftrace_find_tramp_ops_next(rec, ops);
3330 seq_puts(m, "\ttramp: ERROR!");
3332 add_trampoline_func(m, NULL, rec);
3341 static const struct seq_operations show_ftrace_seq_ops = {
3349 ftrace_avail_open(struct inode *inode, struct file *file)
3351 struct ftrace_iterator *iter;
3353 if (unlikely(ftrace_disabled))
3356 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3358 iter->pg = ftrace_pages_start;
3359 iter->ops = &global_ops;
3362 return iter ? 0 : -ENOMEM;
3366 ftrace_enabled_open(struct inode *inode, struct file *file)
3368 struct ftrace_iterator *iter;
3370 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3372 iter->pg = ftrace_pages_start;
3373 iter->flags = FTRACE_ITER_ENABLED;
3374 iter->ops = &global_ops;
3377 return iter ? 0 : -ENOMEM;
3381 * ftrace_regex_open - initialize function tracer filter files
3382 * @ops: The ftrace_ops that hold the hash filters
3383 * @flag: The type of filter to process
3384 * @inode: The inode, usually passed in to your open routine
3385 * @file: The file, usually passed in to your open routine
3387 * ftrace_regex_open() initializes the filter files for the
3388 * @ops. Depending on @flag it may process the filter hash or
3389 * the notrace hash of @ops. With this called from the open
3390 * routine, you can use ftrace_filter_write() for the write
3391 * routine if @flag has FTRACE_ITER_FILTER set, or
3392 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3393 * tracing_lseek() should be used as the lseek routine, and
3394 * release must call ftrace_regex_release().
3397 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3398 struct inode *inode, struct file *file)
3400 struct ftrace_iterator *iter;
3401 struct ftrace_hash *hash;
3404 ftrace_ops_init(ops);
3406 if (unlikely(ftrace_disabled))
3409 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3413 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3421 mutex_lock(&ops->func_hash->regex_lock);
3423 if (flag & FTRACE_ITER_NOTRACE)
3424 hash = ops->func_hash->notrace_hash;
3426 hash = ops->func_hash->filter_hash;
3428 if (file->f_mode & FMODE_WRITE) {
3429 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3431 if (file->f_flags & O_TRUNC)
3432 iter->hash = alloc_ftrace_hash(size_bits);
3434 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3437 trace_parser_put(&iter->parser);
3444 if (file->f_mode & FMODE_READ) {
3445 iter->pg = ftrace_pages_start;
3447 ret = seq_open(file, &show_ftrace_seq_ops);
3449 struct seq_file *m = file->private_data;
3453 free_ftrace_hash(iter->hash);
3454 trace_parser_put(&iter->parser);
3458 file->private_data = iter;
3461 mutex_unlock(&ops->func_hash->regex_lock);
3467 ftrace_filter_open(struct inode *inode, struct file *file)
3469 struct ftrace_ops *ops = inode->i_private;
3471 return ftrace_regex_open(ops,
3472 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3477 ftrace_notrace_open(struct inode *inode, struct file *file)
3479 struct ftrace_ops *ops = inode->i_private;
3481 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3485 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3486 struct ftrace_glob {
3493 * If symbols in an architecture don't correspond exactly to the user-visible
3494 * name of what they represent, it is possible to define this function to
3495 * perform the necessary adjustments.
3497 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3502 static int ftrace_match(char *str, struct ftrace_glob *g)
3507 str = arch_ftrace_match_adjust(str, g->search);
3511 if (strcmp(str, g->search) == 0)
3514 case MATCH_FRONT_ONLY:
3515 if (strncmp(str, g->search, g->len) == 0)
3518 case MATCH_MIDDLE_ONLY:
3519 if (strstr(str, g->search))
3522 case MATCH_END_ONLY:
3524 if (slen >= g->len &&
3525 memcmp(str + slen - g->len, g->search, g->len) == 0)
3529 if (glob_match(g->search, str))
3538 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3540 struct ftrace_func_entry *entry;
3543 entry = ftrace_lookup_ip(hash, rec->ip);
3545 /* Do nothing if it doesn't exist */
3549 free_hash_entry(hash, entry);
3551 /* Do nothing if it exists */
3555 ret = add_hash_entry(hash, rec->ip);
3561 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3562 struct ftrace_glob *mod_g, int exclude_mod)
3564 char str[KSYM_SYMBOL_LEN];
3567 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3570 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3572 /* blank module name to match all modules */
3574 /* blank module globbing: modname xor exclude_mod */
3575 if ((!exclude_mod) != (!modname))
3580 /* not matching the module */
3581 if (!modname || !mod_matches) {
3588 if (mod_matches && exclude_mod)
3592 /* blank search means to match all funcs in the mod */
3597 return ftrace_match(str, func_g);
3601 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3603 struct ftrace_page *pg;
3604 struct dyn_ftrace *rec;
3605 struct ftrace_glob func_g = { .type = MATCH_FULL };
3606 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3607 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3608 int exclude_mod = 0;
3614 func_g.type = filter_parse_regex(func, len, &func_g.search,
3616 func_g.len = strlen(func_g.search);
3620 mod_g.type = filter_parse_regex(mod, strlen(mod),
3621 &mod_g.search, &exclude_mod);
3622 mod_g.len = strlen(mod_g.search);
3625 mutex_lock(&ftrace_lock);
3627 if (unlikely(ftrace_disabled))
3630 do_for_each_ftrace_rec(pg, rec) {
3632 if (rec->flags & FTRACE_FL_DISABLED)
3635 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3636 ret = enter_record(hash, rec, clear_filter);
3643 } while_for_each_ftrace_rec();
3645 mutex_unlock(&ftrace_lock);
3651 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3653 return match_records(hash, buff, len, NULL);
3658 * We register the module command as a template to show others how
3659 * to register the a command as well.
3663 ftrace_mod_callback(struct ftrace_hash *hash,
3664 char *func, char *cmd, char *module, int enable)
3669 * cmd == 'mod' because we only registered this func
3670 * for the 'mod' ftrace_func_command.
3671 * But if you register one func with multiple commands,
3672 * you can tell which command was used by the cmd
3675 ret = match_records(hash, func, strlen(func), module);
3683 static struct ftrace_func_command ftrace_mod_cmd = {
3685 .func = ftrace_mod_callback,
3688 static int __init ftrace_mod_cmd_init(void)
3690 return register_ftrace_command(&ftrace_mod_cmd);
3692 core_initcall(ftrace_mod_cmd_init);
3694 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3695 struct ftrace_ops *op, struct pt_regs *pt_regs)
3697 struct ftrace_func_probe *entry;
3698 struct hlist_head *hhd;
3701 key = hash_long(ip, FTRACE_HASH_BITS);
3703 hhd = &ftrace_func_hash[key];
3705 if (hlist_empty(hhd))
3709 * Disable preemption for these calls to prevent a RCU grace
3710 * period. This syncs the hash iteration and freeing of items
3711 * on the hash. rcu_read_lock is too dangerous here.
3713 preempt_disable_notrace();
3714 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3715 if (entry->ip == ip)
3716 entry->ops->func(ip, parent_ip, &entry->data);
3718 preempt_enable_notrace();
3721 static struct ftrace_ops trace_probe_ops __read_mostly =
3723 .func = function_trace_probe_call,
3724 .flags = FTRACE_OPS_FL_INITIALIZED,
3725 INIT_OPS_HASH(trace_probe_ops)
3728 static int ftrace_probe_registered;
3730 static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3735 if (ftrace_probe_registered) {
3736 /* still need to update the function call sites */
3738 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3743 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3744 struct hlist_head *hhd = &ftrace_func_hash[i];
3748 /* Nothing registered? */
3749 if (i == FTRACE_FUNC_HASHSIZE)
3752 ret = ftrace_startup(&trace_probe_ops, 0);
3754 ftrace_probe_registered = 1;
3757 static void __disable_ftrace_function_probe(void)
3761 if (!ftrace_probe_registered)
3764 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3765 struct hlist_head *hhd = &ftrace_func_hash[i];
3770 /* no more funcs left */
3771 ftrace_shutdown(&trace_probe_ops, 0);
3773 ftrace_probe_registered = 0;
3777 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3779 if (entry->ops->free)
3780 entry->ops->free(entry->ops, entry->ip, &entry->data);
3785 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3788 struct ftrace_ops_hash old_hash_ops;
3789 struct ftrace_func_probe *entry;
3790 struct ftrace_glob func_g;
3791 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3792 struct ftrace_hash *old_hash = *orig_hash;
3793 struct ftrace_hash *hash;
3794 struct ftrace_page *pg;
3795 struct dyn_ftrace *rec;
3801 func_g.type = filter_parse_regex(glob, strlen(glob),
3802 &func_g.search, ¬);
3803 func_g.len = strlen(func_g.search);
3805 /* we do not support '!' for function probes */
3809 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3811 old_hash_ops.filter_hash = old_hash;
3812 /* Probes only have filters */
3813 old_hash_ops.notrace_hash = NULL;
3815 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3821 if (unlikely(ftrace_disabled)) {
3826 mutex_lock(&ftrace_lock);
3828 do_for_each_ftrace_rec(pg, rec) {
3830 if (rec->flags & FTRACE_FL_DISABLED)
3833 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3836 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3838 /* If we did not process any, then return error */
3849 * The caller might want to do something special
3850 * for each function we find. We call the callback
3851 * to give the caller an opportunity to do so.
3854 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3855 /* caller does not like this func */
3861 ret = enter_record(hash, rec, 0);
3869 entry->ip = rec->ip;
3871 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3872 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3874 } while_for_each_ftrace_rec();
3876 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3878 __enable_ftrace_function_probe(&old_hash_ops);
3881 free_ftrace_hash_rcu(old_hash);
3886 mutex_unlock(&ftrace_lock);
3888 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3889 free_ftrace_hash(hash);
3895 PROBE_TEST_FUNC = 1,
3900 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3901 void *data, int flags)
3903 struct ftrace_func_entry *rec_entry;
3904 struct ftrace_func_probe *entry;
3905 struct ftrace_func_probe *p;
3906 struct ftrace_glob func_g;
3907 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3908 struct ftrace_hash *old_hash = *orig_hash;
3909 struct list_head free_list;
3910 struct ftrace_hash *hash;
3911 struct hlist_node *tmp;
3912 char str[KSYM_SYMBOL_LEN];
3915 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3916 func_g.search = NULL;
3920 func_g.type = filter_parse_regex(glob, strlen(glob),
3921 &func_g.search, ¬);
3922 func_g.len = strlen(func_g.search);
3923 func_g.search = glob;
3925 /* we do not support '!' for function probes */
3930 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3932 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3934 /* Hmm, should report this somehow */
3937 INIT_LIST_HEAD(&free_list);
3939 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3940 struct hlist_head *hhd = &ftrace_func_hash[i];
3942 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3944 /* break up if statements for readability */
3945 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3948 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3951 /* do this last, since it is the most expensive */
3952 if (func_g.search) {
3953 kallsyms_lookup(entry->ip, NULL, NULL,
3955 if (!ftrace_match(str, &func_g))
3959 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3960 /* It is possible more than one entry had this ip */
3962 free_hash_entry(hash, rec_entry);
3964 hlist_del_rcu(&entry->node);
3965 list_add(&entry->free_list, &free_list);
3968 mutex_lock(&ftrace_lock);
3969 __disable_ftrace_function_probe();
3971 * Remove after the disable is called. Otherwise, if the last
3972 * probe is removed, a null hash means *all enabled*.
3974 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3975 synchronize_sched();
3977 free_ftrace_hash_rcu(old_hash);
3979 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3980 list_del(&entry->free_list);
3981 ftrace_free_entry(entry);
3983 mutex_unlock(&ftrace_lock);
3986 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3987 free_ftrace_hash(hash);
3991 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3994 __unregister_ftrace_function_probe(glob, ops, data,
3995 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3999 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
4001 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
4004 void unregister_ftrace_function_probe_all(char *glob)
4006 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
4009 static LIST_HEAD(ftrace_commands);
4010 static DEFINE_MUTEX(ftrace_cmd_mutex);
4013 * Currently we only register ftrace commands from __init, so mark this
4016 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4018 struct ftrace_func_command *p;
4021 mutex_lock(&ftrace_cmd_mutex);
4022 list_for_each_entry(p, &ftrace_commands, list) {
4023 if (strcmp(cmd->name, p->name) == 0) {
4028 list_add(&cmd->list, &ftrace_commands);
4030 mutex_unlock(&ftrace_cmd_mutex);
4036 * Currently we only unregister ftrace commands from __init, so mark
4039 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4041 struct ftrace_func_command *p, *n;
4044 mutex_lock(&ftrace_cmd_mutex);
4045 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4046 if (strcmp(cmd->name, p->name) == 0) {
4048 list_del_init(&p->list);
4053 mutex_unlock(&ftrace_cmd_mutex);
4058 static int ftrace_process_regex(struct ftrace_hash *hash,
4059 char *buff, int len, int enable)
4061 char *func, *command, *next = buff;
4062 struct ftrace_func_command *p;
4065 func = strsep(&next, ":");
4068 ret = ftrace_match_records(hash, func, len);
4078 command = strsep(&next, ":");
4080 mutex_lock(&ftrace_cmd_mutex);
4081 list_for_each_entry(p, &ftrace_commands, list) {
4082 if (strcmp(p->name, command) == 0) {
4083 ret = p->func(hash, func, command, next, enable);
4088 mutex_unlock(&ftrace_cmd_mutex);
4094 ftrace_regex_write(struct file *file, const char __user *ubuf,
4095 size_t cnt, loff_t *ppos, int enable)
4097 struct ftrace_iterator *iter;
4098 struct trace_parser *parser;
4104 if (file->f_mode & FMODE_READ) {
4105 struct seq_file *m = file->private_data;
4108 iter = file->private_data;
4110 if (unlikely(ftrace_disabled))
4113 /* iter->hash is a local copy, so we don't need regex_lock */
4115 parser = &iter->parser;
4116 read = trace_get_user(parser, ubuf, cnt, ppos);
4118 if (read >= 0 && trace_parser_loaded(parser) &&
4119 !trace_parser_cont(parser)) {
4120 ret = ftrace_process_regex(iter->hash, parser->buffer,
4121 parser->idx, enable);
4122 trace_parser_clear(parser);
4133 ftrace_filter_write(struct file *file, const char __user *ubuf,
4134 size_t cnt, loff_t *ppos)
4136 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4140 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4141 size_t cnt, loff_t *ppos)
4143 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4147 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4149 struct ftrace_func_entry *entry;
4151 if (!ftrace_location(ip))
4155 entry = ftrace_lookup_ip(hash, ip);
4158 free_hash_entry(hash, entry);
4162 return add_hash_entry(hash, ip);
4165 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4166 struct ftrace_ops_hash *old_hash)
4168 struct ftrace_ops *op;
4170 if (!ftrace_enabled)
4173 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4174 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4179 * If this is the shared global_ops filter, then we need to
4180 * check if there is another ops that shares it, is enabled.
4181 * If so, we still need to run the modify code.
4183 if (ops->func_hash != &global_ops.local_hash)
4186 do_for_each_ftrace_op(op, ftrace_ops_list) {
4187 if (op->func_hash == &global_ops.local_hash &&
4188 op->flags & FTRACE_OPS_FL_ENABLED) {
4189 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4190 /* Only need to do this once */
4193 } while_for_each_ftrace_op(op);
4197 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4198 unsigned long ip, int remove, int reset, int enable)
4200 struct ftrace_hash **orig_hash;
4201 struct ftrace_ops_hash old_hash_ops;
4202 struct ftrace_hash *old_hash;
4203 struct ftrace_hash *hash;
4206 if (unlikely(ftrace_disabled))
4209 mutex_lock(&ops->func_hash->regex_lock);
4212 orig_hash = &ops->func_hash->filter_hash;
4214 orig_hash = &ops->func_hash->notrace_hash;
4217 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4219 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4223 goto out_regex_unlock;
4226 if (buf && !ftrace_match_records(hash, buf, len)) {
4228 goto out_regex_unlock;
4231 ret = ftrace_match_addr(hash, ip, remove);
4233 goto out_regex_unlock;
4236 mutex_lock(&ftrace_lock);
4237 old_hash = *orig_hash;
4238 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4239 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4240 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4242 ftrace_ops_update_code(ops, &old_hash_ops);
4243 free_ftrace_hash_rcu(old_hash);
4245 mutex_unlock(&ftrace_lock);
4248 mutex_unlock(&ops->func_hash->regex_lock);
4250 free_ftrace_hash(hash);
4255 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4256 int reset, int enable)
4258 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4262 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4263 * @ops - the ops to set the filter with
4264 * @ip - the address to add to or remove from the filter.
4265 * @remove - non zero to remove the ip from the filter
4266 * @reset - non zero to reset all filters before applying this filter.
4268 * Filters denote which functions should be enabled when tracing is enabled
4269 * If @ip is NULL, it failes to update filter.
4271 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4272 int remove, int reset)
4274 ftrace_ops_init(ops);
4275 return ftrace_set_addr(ops, ip, remove, reset, 1);
4277 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4280 * ftrace_ops_set_global_filter - setup ops to use global filters
4281 * @ops - the ops which will use the global filters
4283 * ftrace users who need global function trace filtering should call this.
4284 * It can set the global filter only if ops were not initialized before.
4286 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4288 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4291 ftrace_ops_init(ops);
4292 ops->func_hash = &global_ops.local_hash;
4294 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4297 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4298 int reset, int enable)
4300 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4304 * ftrace_set_filter - set a function to filter on in ftrace
4305 * @ops - the ops to set the filter with
4306 * @buf - the string that holds the function filter text.
4307 * @len - the length of the string.
4308 * @reset - non zero to reset all filters before applying this filter.
4310 * Filters denote which functions should be enabled when tracing is enabled.
4311 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4313 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4316 ftrace_ops_init(ops);
4317 return ftrace_set_regex(ops, buf, len, reset, 1);
4319 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4322 * ftrace_set_notrace - set a function to not trace in ftrace
4323 * @ops - the ops to set the notrace filter with
4324 * @buf - the string that holds the function notrace text.
4325 * @len - the length of the string.
4326 * @reset - non zero to reset all filters before applying this filter.
4328 * Notrace Filters denote which functions should not be enabled when tracing
4329 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4332 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4335 ftrace_ops_init(ops);
4336 return ftrace_set_regex(ops, buf, len, reset, 0);
4338 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4340 * ftrace_set_global_filter - set a function to filter on with global tracers
4341 * @buf - the string that holds the function filter text.
4342 * @len - the length of the string.
4343 * @reset - non zero to reset all filters before applying this filter.
4345 * Filters denote which functions should be enabled when tracing is enabled.
4346 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4348 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4350 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4352 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4355 * ftrace_set_global_notrace - set a function to not trace with global tracers
4356 * @buf - the string that holds the function notrace text.
4357 * @len - the length of the string.
4358 * @reset - non zero to reset all filters before applying this filter.
4360 * Notrace Filters denote which functions should not be enabled when tracing
4361 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4364 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4366 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4368 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4371 * command line interface to allow users to set filters on boot up.
4373 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4374 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4375 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4377 /* Used by function selftest to not test if filter is set */
4378 bool ftrace_filter_param __initdata;
4380 static int __init set_ftrace_notrace(char *str)
4382 ftrace_filter_param = true;
4383 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4386 __setup("ftrace_notrace=", set_ftrace_notrace);
4388 static int __init set_ftrace_filter(char *str)
4390 ftrace_filter_param = true;
4391 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4394 __setup("ftrace_filter=", set_ftrace_filter);
4396 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4397 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4398 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4399 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4401 static unsigned long save_global_trampoline;
4402 static unsigned long save_global_flags;
4404 static int __init set_graph_function(char *str)
4406 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4409 __setup("ftrace_graph_filter=", set_graph_function);
4411 static int __init set_graph_notrace_function(char *str)
4413 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4416 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4418 static void __init set_ftrace_early_graph(char *buf, int enable)
4422 struct ftrace_hash *hash;
4425 hash = ftrace_graph_hash;
4427 hash = ftrace_graph_notrace_hash;
4430 func = strsep(&buf, ",");
4431 /* we allow only one expression at a time */
4432 ret = ftrace_graph_set_hash(hash, func);
4434 printk(KERN_DEBUG "ftrace: function %s not "
4435 "traceable\n", func);
4438 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4441 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4445 ftrace_ops_init(ops);
4448 func = strsep(&buf, ",");
4449 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4453 static void __init set_ftrace_early_filters(void)
4455 if (ftrace_filter_buf[0])
4456 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4457 if (ftrace_notrace_buf[0])
4458 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4459 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4460 if (ftrace_graph_buf[0])
4461 set_ftrace_early_graph(ftrace_graph_buf, 1);
4462 if (ftrace_graph_notrace_buf[0])
4463 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4464 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4467 int ftrace_regex_release(struct inode *inode, struct file *file)
4469 struct seq_file *m = (struct seq_file *)file->private_data;
4470 struct ftrace_ops_hash old_hash_ops;
4471 struct ftrace_iterator *iter;
4472 struct ftrace_hash **orig_hash;
4473 struct ftrace_hash *old_hash;
4474 struct trace_parser *parser;
4478 if (file->f_mode & FMODE_READ) {
4480 seq_release(inode, file);
4482 iter = file->private_data;
4484 parser = &iter->parser;
4485 if (trace_parser_loaded(parser)) {
4486 parser->buffer[parser->idx] = 0;
4487 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4490 trace_parser_put(parser);
4492 mutex_lock(&iter->ops->func_hash->regex_lock);
4494 if (file->f_mode & FMODE_WRITE) {
4495 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4498 orig_hash = &iter->ops->func_hash->filter_hash;
4500 orig_hash = &iter->ops->func_hash->notrace_hash;
4502 mutex_lock(&ftrace_lock);
4503 old_hash = *orig_hash;
4504 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4505 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4506 ret = ftrace_hash_move(iter->ops, filter_hash,
4507 orig_hash, iter->hash);
4509 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4510 free_ftrace_hash_rcu(old_hash);
4512 mutex_unlock(&ftrace_lock);
4515 mutex_unlock(&iter->ops->func_hash->regex_lock);
4516 free_ftrace_hash(iter->hash);
4522 static const struct file_operations ftrace_avail_fops = {
4523 .open = ftrace_avail_open,
4525 .llseek = seq_lseek,
4526 .release = seq_release_private,
4529 static const struct file_operations ftrace_enabled_fops = {
4530 .open = ftrace_enabled_open,
4532 .llseek = seq_lseek,
4533 .release = seq_release_private,
4536 static const struct file_operations ftrace_filter_fops = {
4537 .open = ftrace_filter_open,
4539 .write = ftrace_filter_write,
4540 .llseek = tracing_lseek,
4541 .release = ftrace_regex_release,
4544 static const struct file_operations ftrace_notrace_fops = {
4545 .open = ftrace_notrace_open,
4547 .write = ftrace_notrace_write,
4548 .llseek = tracing_lseek,
4549 .release = ftrace_regex_release,
4552 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4554 static DEFINE_MUTEX(graph_lock);
4556 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
4557 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
4559 enum graph_filter_type {
4560 GRAPH_FILTER_NOTRACE = 0,
4561 GRAPH_FILTER_FUNCTION,
4564 #define FTRACE_GRAPH_EMPTY ((void *)1)
4566 struct ftrace_graph_data {
4567 struct ftrace_hash *hash;
4568 struct ftrace_func_entry *entry;
4569 int idx; /* for hash table iteration */
4570 enum graph_filter_type type;
4571 struct ftrace_hash *new_hash;
4572 const struct seq_operations *seq_ops;
4573 struct trace_parser parser;
4577 __g_next(struct seq_file *m, loff_t *pos)
4579 struct ftrace_graph_data *fgd = m->private;
4580 struct ftrace_func_entry *entry = fgd->entry;
4581 struct hlist_head *head;
4582 int i, idx = fgd->idx;
4584 if (*pos >= fgd->hash->count)
4588 hlist_for_each_entry_continue(entry, hlist) {
4596 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
4597 head = &fgd->hash->buckets[i];
4598 hlist_for_each_entry(entry, head, hlist) {
4608 g_next(struct seq_file *m, void *v, loff_t *pos)
4611 return __g_next(m, pos);
4614 static void *g_start(struct seq_file *m, loff_t *pos)
4616 struct ftrace_graph_data *fgd = m->private;
4618 mutex_lock(&graph_lock);
4620 if (fgd->type == GRAPH_FILTER_FUNCTION)
4621 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
4622 lockdep_is_held(&graph_lock));
4624 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
4625 lockdep_is_held(&graph_lock));
4627 /* Nothing, tell g_show to print all functions are enabled */
4628 if (ftrace_hash_empty(fgd->hash) && !*pos)
4629 return FTRACE_GRAPH_EMPTY;
4633 return __g_next(m, pos);
4636 static void g_stop(struct seq_file *m, void *p)
4638 mutex_unlock(&graph_lock);
4641 static int g_show(struct seq_file *m, void *v)
4643 struct ftrace_func_entry *entry = v;
4648 if (entry == FTRACE_GRAPH_EMPTY) {
4649 struct ftrace_graph_data *fgd = m->private;
4651 if (fgd->type == GRAPH_FILTER_FUNCTION)
4652 seq_puts(m, "#### all functions enabled ####\n");
4654 seq_puts(m, "#### no functions disabled ####\n");
4658 seq_printf(m, "%ps\n", (void *)entry->ip);
4663 static const struct seq_operations ftrace_graph_seq_ops = {
4671 __ftrace_graph_open(struct inode *inode, struct file *file,
4672 struct ftrace_graph_data *fgd)
4675 struct ftrace_hash *new_hash = NULL;
4677 if (file->f_mode & FMODE_WRITE) {
4678 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4680 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
4683 if (file->f_flags & O_TRUNC)
4684 new_hash = alloc_ftrace_hash(size_bits);
4686 new_hash = alloc_and_copy_ftrace_hash(size_bits,
4694 if (file->f_mode & FMODE_READ) {
4695 ret = seq_open(file, &ftrace_graph_seq_ops);
4697 struct seq_file *m = file->private_data;
4701 free_ftrace_hash(new_hash);
4705 file->private_data = fgd;
4708 if (ret < 0 && file->f_mode & FMODE_WRITE)
4709 trace_parser_put(&fgd->parser);
4711 fgd->new_hash = new_hash;
4714 * All uses of fgd->hash must be taken with the graph_lock
4715 * held. The graph_lock is going to be released, so force
4716 * fgd->hash to be reinitialized when it is taken again.
4724 ftrace_graph_open(struct inode *inode, struct file *file)
4726 struct ftrace_graph_data *fgd;
4729 if (unlikely(ftrace_disabled))
4732 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4736 mutex_lock(&graph_lock);
4738 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
4739 lockdep_is_held(&graph_lock));
4740 fgd->type = GRAPH_FILTER_FUNCTION;
4741 fgd->seq_ops = &ftrace_graph_seq_ops;
4743 ret = __ftrace_graph_open(inode, file, fgd);
4747 mutex_unlock(&graph_lock);
4752 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4754 struct ftrace_graph_data *fgd;
4757 if (unlikely(ftrace_disabled))
4760 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4764 mutex_lock(&graph_lock);
4766 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
4767 lockdep_is_held(&graph_lock));
4768 fgd->type = GRAPH_FILTER_NOTRACE;
4769 fgd->seq_ops = &ftrace_graph_seq_ops;
4771 ret = __ftrace_graph_open(inode, file, fgd);
4775 mutex_unlock(&graph_lock);
4780 ftrace_graph_release(struct inode *inode, struct file *file)
4782 struct ftrace_graph_data *fgd;
4783 struct ftrace_hash *old_hash, *new_hash;
4784 struct trace_parser *parser;
4787 if (file->f_mode & FMODE_READ) {
4788 struct seq_file *m = file->private_data;
4791 seq_release(inode, file);
4793 fgd = file->private_data;
4797 if (file->f_mode & FMODE_WRITE) {
4799 parser = &fgd->parser;
4801 if (trace_parser_loaded((parser))) {
4802 parser->buffer[parser->idx] = 0;
4803 ret = ftrace_graph_set_hash(fgd->new_hash,
4807 trace_parser_put(parser);
4809 new_hash = __ftrace_hash_move(fgd->new_hash);
4815 mutex_lock(&graph_lock);
4817 if (fgd->type == GRAPH_FILTER_FUNCTION) {
4818 old_hash = rcu_dereference_protected(ftrace_graph_hash,
4819 lockdep_is_held(&graph_lock));
4820 rcu_assign_pointer(ftrace_graph_hash, new_hash);
4822 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
4823 lockdep_is_held(&graph_lock));
4824 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
4827 mutex_unlock(&graph_lock);
4829 /* Wait till all users are no longer using the old hash */
4830 synchronize_sched();
4832 free_ftrace_hash(old_hash);
4836 kfree(fgd->new_hash);
4843 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
4845 struct ftrace_glob func_g;
4846 struct dyn_ftrace *rec;
4847 struct ftrace_page *pg;
4848 struct ftrace_func_entry *entry;
4853 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4854 &func_g.search, ¬);
4856 func_g.len = strlen(func_g.search);
4858 mutex_lock(&ftrace_lock);
4860 if (unlikely(ftrace_disabled)) {
4861 mutex_unlock(&ftrace_lock);
4865 do_for_each_ftrace_rec(pg, rec) {
4867 if (rec->flags & FTRACE_FL_DISABLED)
4870 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4871 entry = ftrace_lookup_ip(hash, rec->ip);
4878 if (add_hash_entry(hash, rec->ip) < 0)
4882 free_hash_entry(hash, entry);
4887 } while_for_each_ftrace_rec();
4889 mutex_unlock(&ftrace_lock);
4898 ftrace_graph_write(struct file *file, const char __user *ubuf,
4899 size_t cnt, loff_t *ppos)
4901 ssize_t read, ret = 0;
4902 struct ftrace_graph_data *fgd = file->private_data;
4903 struct trace_parser *parser;
4908 /* Read mode uses seq functions */
4909 if (file->f_mode & FMODE_READ) {
4910 struct seq_file *m = file->private_data;
4914 parser = &fgd->parser;
4916 read = trace_get_user(parser, ubuf, cnt, ppos);
4918 if (read >= 0 && trace_parser_loaded(parser) &&
4919 !trace_parser_cont(parser)) {
4921 ret = ftrace_graph_set_hash(fgd->new_hash,
4923 trace_parser_clear(parser);
4932 static const struct file_operations ftrace_graph_fops = {
4933 .open = ftrace_graph_open,
4935 .write = ftrace_graph_write,
4936 .llseek = tracing_lseek,
4937 .release = ftrace_graph_release,
4940 static const struct file_operations ftrace_graph_notrace_fops = {
4941 .open = ftrace_graph_notrace_open,
4943 .write = ftrace_graph_write,
4944 .llseek = tracing_lseek,
4945 .release = ftrace_graph_release,
4947 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4949 void ftrace_create_filter_files(struct ftrace_ops *ops,
4950 struct dentry *parent)
4953 trace_create_file("set_ftrace_filter", 0644, parent,
4954 ops, &ftrace_filter_fops);
4956 trace_create_file("set_ftrace_notrace", 0644, parent,
4957 ops, &ftrace_notrace_fops);
4961 * The name "destroy_filter_files" is really a misnomer. Although
4962 * in the future, it may actualy delete the files, but this is
4963 * really intended to make sure the ops passed in are disabled
4964 * and that when this function returns, the caller is free to
4967 * The "destroy" name is only to match the "create" name that this
4968 * should be paired with.
4970 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4972 mutex_lock(&ftrace_lock);
4973 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4974 ftrace_shutdown(ops, 0);
4975 ops->flags |= FTRACE_OPS_FL_DELETED;
4976 mutex_unlock(&ftrace_lock);
4979 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4982 trace_create_file("available_filter_functions", 0444,
4983 d_tracer, NULL, &ftrace_avail_fops);
4985 trace_create_file("enabled_functions", 0444,
4986 d_tracer, NULL, &ftrace_enabled_fops);
4988 ftrace_create_filter_files(&global_ops, d_tracer);
4990 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4991 trace_create_file("set_graph_function", 0444, d_tracer,
4993 &ftrace_graph_fops);
4994 trace_create_file("set_graph_notrace", 0444, d_tracer,
4996 &ftrace_graph_notrace_fops);
4997 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5002 static int ftrace_cmp_ips(const void *a, const void *b)
5004 const unsigned long *ipa = a;
5005 const unsigned long *ipb = b;
5014 static int ftrace_process_locs(struct module *mod,
5015 unsigned long *start,
5018 struct ftrace_page *start_pg;
5019 struct ftrace_page *pg;
5020 struct dyn_ftrace *rec;
5021 unsigned long count;
5024 unsigned long flags = 0; /* Shut up gcc */
5027 count = end - start;
5032 sort(start, count, sizeof(*start),
5033 ftrace_cmp_ips, NULL);
5035 start_pg = ftrace_allocate_pages(count);
5039 mutex_lock(&ftrace_lock);
5042 * Core and each module needs their own pages, as
5043 * modules will free them when they are removed.
5044 * Force a new page to be allocated for modules.
5047 WARN_ON(ftrace_pages || ftrace_pages_start);
5048 /* First initialization */
5049 ftrace_pages = ftrace_pages_start = start_pg;
5054 if (WARN_ON(ftrace_pages->next)) {
5055 /* Hmm, we have free pages? */
5056 while (ftrace_pages->next)
5057 ftrace_pages = ftrace_pages->next;
5060 ftrace_pages->next = start_pg;
5066 addr = ftrace_call_adjust(*p++);
5068 * Some architecture linkers will pad between
5069 * the different mcount_loc sections of different
5070 * object files to satisfy alignments.
5071 * Skip any NULL pointers.
5076 if (pg->index == pg->size) {
5077 /* We should have allocated enough */
5078 if (WARN_ON(!pg->next))
5083 rec = &pg->records[pg->index++];
5087 /* We should have used all pages */
5090 /* Assign the last page to ftrace_pages */
5094 * We only need to disable interrupts on start up
5095 * because we are modifying code that an interrupt
5096 * may execute, and the modification is not atomic.
5097 * But for modules, nothing runs the code we modify
5098 * until we are finished with it, and there's no
5099 * reason to cause large interrupt latencies while we do it.
5102 local_irq_save(flags);
5103 ftrace_update_code(mod, start_pg);
5105 local_irq_restore(flags);
5108 mutex_unlock(&ftrace_lock);
5113 #ifdef CONFIG_MODULES
5115 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5117 static int referenced_filters(struct dyn_ftrace *rec)
5119 struct ftrace_ops *ops;
5122 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5123 if (ops_references_rec(ops, rec))
5130 void ftrace_release_mod(struct module *mod)
5132 struct dyn_ftrace *rec;
5133 struct ftrace_page **last_pg;
5134 struct ftrace_page *pg;
5137 mutex_lock(&ftrace_lock);
5139 if (ftrace_disabled)
5143 * Each module has its own ftrace_pages, remove
5144 * them from the list.
5146 last_pg = &ftrace_pages_start;
5147 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5148 rec = &pg->records[0];
5149 if (within_module_core(rec->ip, mod)) {
5151 * As core pages are first, the first
5152 * page should never be a module page.
5154 if (WARN_ON(pg == ftrace_pages_start))
5157 /* Check if we are deleting the last page */
5158 if (pg == ftrace_pages)
5159 ftrace_pages = next_to_ftrace_page(last_pg);
5161 *last_pg = pg->next;
5162 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5163 free_pages((unsigned long)pg->records, order);
5166 last_pg = &pg->next;
5169 mutex_unlock(&ftrace_lock);
5172 void ftrace_module_enable(struct module *mod)
5174 struct dyn_ftrace *rec;
5175 struct ftrace_page *pg;
5177 mutex_lock(&ftrace_lock);
5179 if (ftrace_disabled)
5183 * If the tracing is enabled, go ahead and enable the record.
5185 * The reason not to enable the record immediatelly is the
5186 * inherent check of ftrace_make_nop/ftrace_make_call for
5187 * correct previous instructions. Making first the NOP
5188 * conversion puts the module to the correct state, thus
5189 * passing the ftrace_make_call check.
5191 * We also delay this to after the module code already set the
5192 * text to read-only, as we now need to set it back to read-write
5193 * so that we can modify the text.
5195 if (ftrace_start_up)
5196 ftrace_arch_code_modify_prepare();
5198 do_for_each_ftrace_rec(pg, rec) {
5201 * do_for_each_ftrace_rec() is a double loop.
5202 * module text shares the pg. If a record is
5203 * not part of this module, then skip this pg,
5204 * which the "break" will do.
5206 if (!within_module_core(rec->ip, mod))
5212 * When adding a module, we need to check if tracers are
5213 * currently enabled and if they are, and can trace this record,
5214 * we need to enable the module functions as well as update the
5215 * reference counts for those function records.
5217 if (ftrace_start_up)
5218 cnt += referenced_filters(rec);
5220 /* This clears FTRACE_FL_DISABLED */
5223 if (ftrace_start_up && cnt) {
5224 int failed = __ftrace_replace_code(rec, 1);
5226 ftrace_bug(failed, rec);
5231 } while_for_each_ftrace_rec();
5234 if (ftrace_start_up)
5235 ftrace_arch_code_modify_post_process();
5238 mutex_unlock(&ftrace_lock);
5241 void ftrace_module_init(struct module *mod)
5243 if (ftrace_disabled || !mod->num_ftrace_callsites)
5246 ftrace_process_locs(mod, mod->ftrace_callsites,
5247 mod->ftrace_callsites + mod->num_ftrace_callsites);
5249 #endif /* CONFIG_MODULES */
5251 void __init ftrace_init(void)
5253 extern unsigned long __start_mcount_loc[];
5254 extern unsigned long __stop_mcount_loc[];
5255 unsigned long count, flags;
5258 local_irq_save(flags);
5259 ret = ftrace_dyn_arch_init();
5260 local_irq_restore(flags);
5264 count = __stop_mcount_loc - __start_mcount_loc;
5266 pr_info("ftrace: No functions to be traced?\n");
5270 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5271 count, count / ENTRIES_PER_PAGE + 1);
5273 last_ftrace_enabled = ftrace_enabled = 1;
5275 ret = ftrace_process_locs(NULL,
5279 set_ftrace_early_filters();
5283 ftrace_disabled = 1;
5286 /* Do nothing if arch does not support this */
5287 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5291 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5295 * Currently there's no safe way to free a trampoline when the kernel
5296 * is configured with PREEMPT. That is because a task could be preempted
5297 * when it jumped to the trampoline, it may be preempted for a long time
5298 * depending on the system load, and currently there's no way to know
5299 * when it will be off the trampoline. If the trampoline is freed
5300 * too early, when the task runs again, it will be executing on freed
5303 #ifdef CONFIG_PREEMPT
5304 /* Currently, only non dynamic ops can have a trampoline */
5305 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5309 arch_ftrace_update_trampoline(ops);
5314 static struct ftrace_ops global_ops = {
5315 .func = ftrace_stub,
5316 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5317 FTRACE_OPS_FL_INITIALIZED |
5321 static int __init ftrace_nodyn_init(void)
5326 core_initcall(ftrace_nodyn_init);
5328 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5329 static inline void ftrace_startup_enable(int command) { }
5330 static inline void ftrace_startup_all(int command) { }
5331 /* Keep as macros so we do not need to define the commands */
5332 # define ftrace_startup(ops, command) \
5334 int ___ret = __register_ftrace_function(ops); \
5336 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5339 # define ftrace_shutdown(ops, command) \
5341 int ___ret = __unregister_ftrace_function(ops); \
5343 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5347 # define ftrace_startup_sysctl() do { } while (0)
5348 # define ftrace_shutdown_sysctl() do { } while (0)
5351 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5356 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5360 #endif /* CONFIG_DYNAMIC_FTRACE */
5362 __init void ftrace_init_global_array_ops(struct trace_array *tr)
5364 tr->ops = &global_ops;
5365 tr->ops->private = tr;
5368 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5370 /* If we filter on pids, update to use the pid function */
5371 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5372 if (WARN_ON(tr->ops->func != ftrace_stub))
5373 printk("ftrace ops had %pS for function\n",
5376 tr->ops->func = func;
5377 tr->ops->private = tr;
5380 void ftrace_reset_array_ops(struct trace_array *tr)
5382 tr->ops->func = ftrace_stub;
5386 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5387 struct ftrace_ops *ignored, struct pt_regs *regs)
5389 struct ftrace_ops *op;
5392 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5397 * Some of the ops may be dynamically allocated,
5398 * they must be freed after a synchronize_sched().
5400 preempt_disable_notrace();
5402 do_for_each_ftrace_op(op, ftrace_ops_list) {
5404 * Check the following for each ops before calling their func:
5405 * if RCU flag is set, then rcu_is_watching() must be true
5406 * if PER_CPU is set, then ftrace_function_local_disable()
5408 * Otherwise test if the ip matches the ops filter
5410 * If any of the above fails then the op->func() is not executed.
5412 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5413 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5414 !ftrace_function_local_disabled(op)) &&
5415 ftrace_ops_test(op, ip, regs)) {
5417 if (FTRACE_WARN_ON(!op->func)) {
5418 pr_warn("op=%p %pS\n", op, op);
5421 op->func(ip, parent_ip, op, regs);
5423 } while_for_each_ftrace_op(op);
5425 preempt_enable_notrace();
5426 trace_clear_recursion(bit);
5430 * Some archs only support passing ip and parent_ip. Even though
5431 * the list function ignores the op parameter, we do not want any
5432 * C side effects, where a function is called without the caller
5433 * sending a third parameter.
5434 * Archs are to support both the regs and ftrace_ops at the same time.
5435 * If they support ftrace_ops, it is assumed they support regs.
5436 * If call backs want to use regs, they must either check for regs
5437 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5438 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5439 * An architecture can pass partial regs with ftrace_ops and still
5440 * set the ARCH_SUPPORTS_FTRACE_OPS.
5442 #if ARCH_SUPPORTS_FTRACE_OPS
5443 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5444 struct ftrace_ops *op, struct pt_regs *regs)
5446 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5449 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5451 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5456 * If there's only one function registered but it does not support
5457 * recursion, needs RCU protection and/or requires per cpu handling, then
5458 * this function will be called by the mcount trampoline.
5460 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
5461 struct ftrace_ops *op, struct pt_regs *regs)
5465 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
5468 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5472 preempt_disable_notrace();
5474 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5475 !ftrace_function_local_disabled(op)) {
5476 op->func(ip, parent_ip, op, regs);
5479 preempt_enable_notrace();
5480 trace_clear_recursion(bit);
5484 * ftrace_ops_get_func - get the function a trampoline should call
5485 * @ops: the ops to get the function for
5487 * Normally the mcount trampoline will call the ops->func, but there
5488 * are times that it should not. For example, if the ops does not
5489 * have its own recursion protection, then it should call the
5490 * ftrace_ops_recurs_func() instead.
5492 * Returns the function that the trampoline should call for @ops.
5494 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5497 * If the function does not handle recursion, needs to be RCU safe,
5498 * or does per cpu logic, then we need to call the assist handler.
5500 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
5501 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
5502 return ftrace_ops_assist_func;
5508 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
5509 struct task_struct *prev, struct task_struct *next)
5511 struct trace_array *tr = data;
5512 struct trace_pid_list *pid_list;
5514 pid_list = rcu_dereference_sched(tr->function_pids);
5516 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
5517 trace_ignore_this_task(pid_list, next));
5520 static void clear_ftrace_pids(struct trace_array *tr)
5522 struct trace_pid_list *pid_list;
5525 pid_list = rcu_dereference_protected(tr->function_pids,
5526 lockdep_is_held(&ftrace_lock));
5530 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
5532 for_each_possible_cpu(cpu)
5533 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
5535 rcu_assign_pointer(tr->function_pids, NULL);
5537 /* Wait till all users are no longer using pid filtering */
5538 synchronize_sched();
5540 trace_free_pid_list(pid_list);
5543 static void ftrace_pid_reset(struct trace_array *tr)
5545 mutex_lock(&ftrace_lock);
5546 clear_ftrace_pids(tr);
5548 ftrace_update_pid_func();
5549 ftrace_startup_all(0);
5551 mutex_unlock(&ftrace_lock);
5554 /* Greater than any max PID */
5555 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
5557 static void *fpid_start(struct seq_file *m, loff_t *pos)
5560 struct trace_pid_list *pid_list;
5561 struct trace_array *tr = m->private;
5563 mutex_lock(&ftrace_lock);
5564 rcu_read_lock_sched();
5566 pid_list = rcu_dereference_sched(tr->function_pids);
5569 return !(*pos) ? FTRACE_NO_PIDS : NULL;
5571 return trace_pid_start(pid_list, pos);
5574 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5576 struct trace_array *tr = m->private;
5577 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
5579 if (v == FTRACE_NO_PIDS)
5582 return trace_pid_next(pid_list, v, pos);
5585 static void fpid_stop(struct seq_file *m, void *p)
5588 rcu_read_unlock_sched();
5589 mutex_unlock(&ftrace_lock);
5592 static int fpid_show(struct seq_file *m, void *v)
5594 if (v == FTRACE_NO_PIDS) {
5595 seq_puts(m, "no pid\n");
5599 return trace_pid_show(m, v);
5602 static const struct seq_operations ftrace_pid_sops = {
5603 .start = fpid_start,
5610 ftrace_pid_open(struct inode *inode, struct file *file)
5612 struct trace_array *tr = inode->i_private;
5616 if (trace_array_get(tr) < 0)
5619 if ((file->f_mode & FMODE_WRITE) &&
5620 (file->f_flags & O_TRUNC))
5621 ftrace_pid_reset(tr);
5623 ret = seq_open(file, &ftrace_pid_sops);
5625 trace_array_put(tr);
5627 m = file->private_data;
5628 /* copy tr over to seq ops */
5635 static void ignore_task_cpu(void *data)
5637 struct trace_array *tr = data;
5638 struct trace_pid_list *pid_list;
5641 * This function is called by on_each_cpu() while the
5642 * event_mutex is held.
5644 pid_list = rcu_dereference_protected(tr->function_pids,
5645 mutex_is_locked(&ftrace_lock));
5647 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
5648 trace_ignore_this_task(pid_list, current));
5652 ftrace_pid_write(struct file *filp, const char __user *ubuf,
5653 size_t cnt, loff_t *ppos)
5655 struct seq_file *m = filp->private_data;
5656 struct trace_array *tr = m->private;
5657 struct trace_pid_list *filtered_pids = NULL;
5658 struct trace_pid_list *pid_list;
5664 mutex_lock(&ftrace_lock);
5666 filtered_pids = rcu_dereference_protected(tr->function_pids,
5667 lockdep_is_held(&ftrace_lock));
5669 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
5673 rcu_assign_pointer(tr->function_pids, pid_list);
5675 if (filtered_pids) {
5676 synchronize_sched();
5677 trace_free_pid_list(filtered_pids);
5678 } else if (pid_list) {
5679 /* Register a probe to set whether to ignore the tracing of a task */
5680 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
5684 * Ignoring of pids is done at task switch. But we have to
5685 * check for those tasks that are currently running.
5686 * Always do this in case a pid was appended or removed.
5688 on_each_cpu(ignore_task_cpu, tr, 1);
5690 ftrace_update_pid_func();
5691 ftrace_startup_all(0);
5693 mutex_unlock(&ftrace_lock);
5702 ftrace_pid_release(struct inode *inode, struct file *file)
5704 struct trace_array *tr = inode->i_private;
5706 trace_array_put(tr);
5708 return seq_release(inode, file);
5711 static const struct file_operations ftrace_pid_fops = {
5712 .open = ftrace_pid_open,
5713 .write = ftrace_pid_write,
5715 .llseek = tracing_lseek,
5716 .release = ftrace_pid_release,
5719 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
5721 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5722 tr, &ftrace_pid_fops);
5725 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
5726 struct dentry *d_tracer)
5728 /* Only the top level directory has the dyn_tracefs and profile */
5729 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
5731 ftrace_init_dyn_tracefs(d_tracer);
5732 ftrace_profile_tracefs(d_tracer);
5736 * ftrace_kill - kill ftrace
5738 * This function should be used by panic code. It stops ftrace
5739 * but in a not so nice way. If you need to simply kill ftrace
5740 * from a non-atomic section, use ftrace_kill.
5742 void ftrace_kill(void)
5744 ftrace_disabled = 1;
5746 clear_ftrace_function();
5750 * Test if ftrace is dead or not.
5752 int ftrace_is_dead(void)
5754 return ftrace_disabled;
5758 * register_ftrace_function - register a function for profiling
5759 * @ops - ops structure that holds the function for profiling.
5761 * Register a function to be called by all functions in the
5764 * Note: @ops->func and all the functions it calls must be labeled
5765 * with "notrace", otherwise it will go into a
5768 int register_ftrace_function(struct ftrace_ops *ops)
5772 ftrace_ops_init(ops);
5774 mutex_lock(&ftrace_lock);
5776 ret = ftrace_startup(ops, 0);
5778 mutex_unlock(&ftrace_lock);
5782 EXPORT_SYMBOL_GPL(register_ftrace_function);
5785 * unregister_ftrace_function - unregister a function for profiling.
5786 * @ops - ops structure that holds the function to unregister
5788 * Unregister a function that was added to be called by ftrace profiling.
5790 int unregister_ftrace_function(struct ftrace_ops *ops)
5794 mutex_lock(&ftrace_lock);
5795 ret = ftrace_shutdown(ops, 0);
5796 mutex_unlock(&ftrace_lock);
5800 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5803 ftrace_enable_sysctl(struct ctl_table *table, int write,
5804 void __user *buffer, size_t *lenp,
5809 mutex_lock(&ftrace_lock);
5811 if (unlikely(ftrace_disabled))
5814 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5816 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5819 last_ftrace_enabled = !!ftrace_enabled;
5821 if (ftrace_enabled) {
5823 /* we are starting ftrace again */
5824 if (ftrace_ops_list != &ftrace_list_end)
5825 update_ftrace_function();
5827 ftrace_startup_sysctl();
5830 /* stopping ftrace calls (just send to ftrace_stub) */
5831 ftrace_trace_function = ftrace_stub;
5833 ftrace_shutdown_sysctl();
5837 mutex_unlock(&ftrace_lock);
5841 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5843 static struct ftrace_ops graph_ops = {
5844 .func = ftrace_stub,
5845 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5846 FTRACE_OPS_FL_INITIALIZED |
5849 #ifdef FTRACE_GRAPH_TRAMP_ADDR
5850 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5851 /* trampoline_size is only needed for dynamically allocated tramps */
5853 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5856 void ftrace_graph_sleep_time_control(bool enable)
5858 fgraph_sleep_time = enable;
5861 void ftrace_graph_graph_time_control(bool enable)
5863 fgraph_graph_time = enable;
5866 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5871 /* The callbacks that hook a function */
5872 trace_func_graph_ret_t ftrace_graph_return =
5873 (trace_func_graph_ret_t)ftrace_stub;
5874 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5875 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5877 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5878 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5882 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5883 struct task_struct *g, *t;
5885 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5886 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5887 * sizeof(struct ftrace_ret_stack),
5889 if (!ret_stack_list[i]) {
5897 read_lock(&tasklist_lock);
5898 do_each_thread(g, t) {
5904 if (t->ret_stack == NULL) {
5905 atomic_set(&t->tracing_graph_pause, 0);
5906 atomic_set(&t->trace_overrun, 0);
5907 t->curr_ret_stack = -1;
5908 /* Make sure the tasks see the -1 first: */
5910 t->ret_stack = ret_stack_list[start++];
5912 } while_each_thread(g, t);
5915 read_unlock(&tasklist_lock);
5917 for (i = start; i < end; i++)
5918 kfree(ret_stack_list[i]);
5923 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5924 struct task_struct *prev, struct task_struct *next)
5926 unsigned long long timestamp;
5930 * Does the user want to count the time a function was asleep.
5931 * If so, do not update the time stamps.
5933 if (fgraph_sleep_time)
5936 timestamp = trace_clock_local();
5938 prev->ftrace_timestamp = timestamp;
5940 /* only process tasks that we timestamped */
5941 if (!next->ftrace_timestamp)
5945 * Update all the counters in next to make up for the
5946 * time next was sleeping.
5948 timestamp -= next->ftrace_timestamp;
5950 for (index = next->curr_ret_stack; index >= 0; index--)
5951 next->ret_stack[index].calltime += timestamp;
5954 /* Allocate a return stack for each task */
5955 static int start_graph_tracing(void)
5957 struct ftrace_ret_stack **ret_stack_list;
5960 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5961 sizeof(struct ftrace_ret_stack *),
5964 if (!ret_stack_list)
5967 /* The cpu_boot init_task->ret_stack will never be freed */
5968 for_each_online_cpu(cpu) {
5969 if (!idle_task(cpu)->ret_stack)
5970 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5974 ret = alloc_retstack_tasklist(ret_stack_list);
5975 } while (ret == -EAGAIN);
5978 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5980 pr_info("ftrace_graph: Couldn't activate tracepoint"
5981 " probe to kernel_sched_switch\n");
5984 kfree(ret_stack_list);
5989 * Hibernation protection.
5990 * The state of the current task is too much unstable during
5991 * suspend/restore to disk. We want to protect against that.
5994 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5998 case PM_HIBERNATION_PREPARE:
5999 pause_graph_tracing();
6002 case PM_POST_HIBERNATION:
6003 unpause_graph_tracing();
6009 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
6011 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
6013 return __ftrace_graph_entry(trace);
6017 * The function graph tracer should only trace the functions defined
6018 * by set_ftrace_filter and set_ftrace_notrace. If another function
6019 * tracer ops is registered, the graph tracer requires testing the
6020 * function against the global ops, and not just trace any function
6021 * that any ftrace_ops registered.
6023 static void update_function_graph_func(void)
6025 struct ftrace_ops *op;
6026 bool do_test = false;
6029 * The graph and global ops share the same set of functions
6030 * to test. If any other ops is on the list, then
6031 * the graph tracing needs to test if its the function
6034 do_for_each_ftrace_op(op, ftrace_ops_list) {
6035 if (op != &global_ops && op != &graph_ops &&
6036 op != &ftrace_list_end) {
6038 /* in double loop, break out with goto */
6041 } while_for_each_ftrace_op(op);
6044 ftrace_graph_entry = ftrace_graph_entry_test;
6046 ftrace_graph_entry = __ftrace_graph_entry;
6049 static struct notifier_block ftrace_suspend_notifier = {
6050 .notifier_call = ftrace_suspend_notifier_call,
6053 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
6054 trace_func_graph_ent_t entryfunc)
6058 mutex_lock(&ftrace_lock);
6060 /* we currently allow only one tracer registered at a time */
6061 if (ftrace_graph_active) {
6066 register_pm_notifier(&ftrace_suspend_notifier);
6068 ftrace_graph_active++;
6069 ret = start_graph_tracing();
6071 ftrace_graph_active--;
6075 ftrace_graph_return = retfunc;
6078 * Update the indirect function to the entryfunc, and the
6079 * function that gets called to the entry_test first. Then
6080 * call the update fgraph entry function to determine if
6081 * the entryfunc should be called directly or not.
6083 __ftrace_graph_entry = entryfunc;
6084 ftrace_graph_entry = ftrace_graph_entry_test;
6085 update_function_graph_func();
6087 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
6089 mutex_unlock(&ftrace_lock);
6093 void unregister_ftrace_graph(void)
6095 mutex_lock(&ftrace_lock);
6097 if (unlikely(!ftrace_graph_active))
6100 ftrace_graph_active--;
6101 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
6102 ftrace_graph_entry = ftrace_graph_entry_stub;
6103 __ftrace_graph_entry = ftrace_graph_entry_stub;
6104 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
6105 unregister_pm_notifier(&ftrace_suspend_notifier);
6106 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
6108 #ifdef CONFIG_DYNAMIC_FTRACE
6110 * Function graph does not allocate the trampoline, but
6111 * other global_ops do. We need to reset the ALLOC_TRAMP flag
6114 global_ops.trampoline = save_global_trampoline;
6115 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
6116 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
6120 mutex_unlock(&ftrace_lock);
6123 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
6126 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
6128 atomic_set(&t->tracing_graph_pause, 0);
6129 atomic_set(&t->trace_overrun, 0);
6130 t->ftrace_timestamp = 0;
6131 /* make curr_ret_stack visible before we add the ret_stack */
6133 t->ret_stack = ret_stack;
6137 * Allocate a return stack for the idle task. May be the first
6138 * time through, or it may be done by CPU hotplug online.
6140 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
6142 t->curr_ret_stack = -1;
6144 * The idle task has no parent, it either has its own
6145 * stack or no stack at all.
6148 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
6150 if (ftrace_graph_active) {
6151 struct ftrace_ret_stack *ret_stack;
6153 ret_stack = per_cpu(idle_ret_stack, cpu);
6155 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6156 * sizeof(struct ftrace_ret_stack),
6160 per_cpu(idle_ret_stack, cpu) = ret_stack;
6162 graph_init_task(t, ret_stack);
6166 /* Allocate a return stack for newly created task */
6167 void ftrace_graph_init_task(struct task_struct *t)
6169 /* Make sure we do not use the parent ret_stack */
6170 t->ret_stack = NULL;
6171 t->curr_ret_stack = -1;
6173 if (ftrace_graph_active) {
6174 struct ftrace_ret_stack *ret_stack;
6176 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6177 * sizeof(struct ftrace_ret_stack),
6181 graph_init_task(t, ret_stack);
6185 void ftrace_graph_exit_task(struct task_struct *t)
6187 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6189 t->ret_stack = NULL;
6190 /* NULL must become visible to IRQs before we free it: */