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 /* List for set_ftrace_pid's pids. */
93 LIST_HEAD(ftrace_pids);
95 struct list_head list;
99 static bool ftrace_pids_enabled(void)
101 return !list_empty(&ftrace_pids);
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 if (!test_tsk_trace_trace(current))
185 op->saved_func(ip, parent_ip, op, regs);
189 * clear_ftrace_function - reset the ftrace function
191 * This NULLs the ftrace function and in essence stops
192 * tracing. There may be lag
194 void clear_ftrace_function(void)
196 ftrace_trace_function = ftrace_stub;
199 static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
203 for_each_possible_cpu(cpu)
204 *per_cpu_ptr(ops->disabled, cpu) = 1;
207 static int per_cpu_ops_alloc(struct ftrace_ops *ops)
209 int __percpu *disabled;
211 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
214 disabled = alloc_percpu(int);
218 ops->disabled = disabled;
219 per_cpu_ops_disable_all(ops);
223 static void ftrace_sync(struct work_struct *work)
226 * This function is just a stub to implement a hard force
227 * of synchronize_sched(). This requires synchronizing
228 * tasks even in userspace and idle.
230 * Yes, function tracing is rude.
234 static void ftrace_sync_ipi(void *data)
236 /* Probably not needed, but do it anyway */
240 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
241 static void update_function_graph_func(void);
243 /* Both enabled by default (can be cleared by function_graph tracer flags */
244 static bool fgraph_sleep_time = true;
245 static bool fgraph_graph_time = true;
248 static inline void update_function_graph_func(void) { }
252 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
255 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
256 * then it needs to call the list anyway.
258 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
259 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
260 return ftrace_ops_list_func;
262 return ftrace_ops_get_func(ops);
265 static void update_ftrace_function(void)
270 * Prepare the ftrace_ops that the arch callback will use.
271 * If there's only one ftrace_ops registered, the ftrace_ops_list
272 * will point to the ops we want.
274 set_function_trace_op = ftrace_ops_list;
276 /* If there's no ftrace_ops registered, just call the stub function */
277 if (ftrace_ops_list == &ftrace_list_end) {
281 * If we are at the end of the list and this ops is
282 * recursion safe and not dynamic and the arch supports passing ops,
283 * then have the mcount trampoline call the function directly.
285 } else if (ftrace_ops_list->next == &ftrace_list_end) {
286 func = ftrace_ops_get_list_func(ftrace_ops_list);
289 /* Just use the default ftrace_ops */
290 set_function_trace_op = &ftrace_list_end;
291 func = ftrace_ops_list_func;
294 update_function_graph_func();
296 /* If there's no change, then do nothing more here */
297 if (ftrace_trace_function == func)
301 * If we are using the list function, it doesn't care
302 * about the function_trace_ops.
304 if (func == ftrace_ops_list_func) {
305 ftrace_trace_function = func;
307 * Don't even bother setting function_trace_ops,
308 * it would be racy to do so anyway.
313 #ifndef CONFIG_DYNAMIC_FTRACE
315 * For static tracing, we need to be a bit more careful.
316 * The function change takes affect immediately. Thus,
317 * we need to coorditate the setting of the function_trace_ops
318 * with the setting of the ftrace_trace_function.
320 * Set the function to the list ops, which will call the
321 * function we want, albeit indirectly, but it handles the
322 * ftrace_ops and doesn't depend on function_trace_op.
324 ftrace_trace_function = ftrace_ops_list_func;
326 * Make sure all CPUs see this. Yes this is slow, but static
327 * tracing is slow and nasty to have enabled.
329 schedule_on_each_cpu(ftrace_sync);
330 /* Now all cpus are using the list ops. */
331 function_trace_op = set_function_trace_op;
332 /* Make sure the function_trace_op is visible on all CPUs */
334 /* Nasty way to force a rmb on all cpus */
335 smp_call_function(ftrace_sync_ipi, NULL, 1);
336 /* OK, we are all set to update the ftrace_trace_function now! */
337 #endif /* !CONFIG_DYNAMIC_FTRACE */
339 ftrace_trace_function = func;
342 int using_ftrace_ops_list_func(void)
344 return ftrace_trace_function == ftrace_ops_list_func;
347 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
351 * We are entering ops into the list but another
352 * CPU might be walking that list. We need to make sure
353 * the ops->next pointer is valid before another CPU sees
354 * the ops pointer included into the list.
356 rcu_assign_pointer(*list, ops);
359 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
361 struct ftrace_ops **p;
364 * If we are removing the last function, then simply point
365 * to the ftrace_stub.
367 if (*list == ops && ops->next == &ftrace_list_end) {
368 *list = &ftrace_list_end;
372 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
383 static void ftrace_update_trampoline(struct ftrace_ops *ops);
385 static int __register_ftrace_function(struct ftrace_ops *ops)
387 if (ops->flags & FTRACE_OPS_FL_DELETED)
390 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
393 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
395 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
396 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
397 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
399 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
400 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
403 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
404 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
407 if (!core_kernel_data((unsigned long)ops))
408 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
410 if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
411 if (per_cpu_ops_alloc(ops))
415 add_ftrace_ops(&ftrace_ops_list, ops);
417 /* Always save the function, and reset at unregistering */
418 ops->saved_func = ops->func;
420 if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
421 ops->func = ftrace_pid_func;
423 ftrace_update_trampoline(ops);
426 update_ftrace_function();
431 static int __unregister_ftrace_function(struct ftrace_ops *ops)
435 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
438 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
444 update_ftrace_function();
446 ops->func = ops->saved_func;
451 static void ftrace_update_pid_func(void)
453 bool enabled = ftrace_pids_enabled();
454 struct ftrace_ops *op;
456 /* Only do something if we are tracing something */
457 if (ftrace_trace_function == ftrace_stub)
460 do_for_each_ftrace_op(op, ftrace_ops_list) {
461 if (op->flags & FTRACE_OPS_FL_PID) {
462 op->func = enabled ? ftrace_pid_func :
464 ftrace_update_trampoline(op);
466 } while_for_each_ftrace_op(op);
468 update_ftrace_function();
471 #ifdef CONFIG_FUNCTION_PROFILER
472 struct ftrace_profile {
473 struct hlist_node node;
475 unsigned long counter;
476 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
477 unsigned long long time;
478 unsigned long long time_squared;
482 struct ftrace_profile_page {
483 struct ftrace_profile_page *next;
485 struct ftrace_profile records[];
488 struct ftrace_profile_stat {
490 struct hlist_head *hash;
491 struct ftrace_profile_page *pages;
492 struct ftrace_profile_page *start;
493 struct tracer_stat stat;
496 #define PROFILE_RECORDS_SIZE \
497 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
499 #define PROFILES_PER_PAGE \
500 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
502 static int ftrace_profile_enabled __read_mostly;
504 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
505 static DEFINE_MUTEX(ftrace_profile_lock);
507 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
509 #define FTRACE_PROFILE_HASH_BITS 10
510 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
513 function_stat_next(void *v, int idx)
515 struct ftrace_profile *rec = v;
516 struct ftrace_profile_page *pg;
518 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
524 if ((void *)rec >= (void *)&pg->records[pg->index]) {
528 rec = &pg->records[0];
536 static void *function_stat_start(struct tracer_stat *trace)
538 struct ftrace_profile_stat *stat =
539 container_of(trace, struct ftrace_profile_stat, stat);
541 if (!stat || !stat->start)
544 return function_stat_next(&stat->start->records[0], 0);
547 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
548 /* function graph compares on total time */
549 static int function_stat_cmp(void *p1, void *p2)
551 struct ftrace_profile *a = p1;
552 struct ftrace_profile *b = p2;
554 if (a->time < b->time)
556 if (a->time > b->time)
562 /* not function graph compares against hits */
563 static int function_stat_cmp(void *p1, void *p2)
565 struct ftrace_profile *a = p1;
566 struct ftrace_profile *b = p2;
568 if (a->counter < b->counter)
570 if (a->counter > b->counter)
577 static int function_stat_headers(struct seq_file *m)
579 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
580 seq_puts(m, " Function "
583 "--- ---- --- ---\n");
585 seq_puts(m, " Function Hit\n"
591 static int function_stat_show(struct seq_file *m, void *v)
593 struct ftrace_profile *rec = v;
594 char str[KSYM_SYMBOL_LEN];
596 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
597 static struct trace_seq s;
598 unsigned long long avg;
599 unsigned long long stddev;
601 mutex_lock(&ftrace_profile_lock);
603 /* we raced with function_profile_reset() */
604 if (unlikely(rec->counter == 0)) {
609 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
611 do_div(avg, rec->counter);
612 if (tracing_thresh && (avg < tracing_thresh))
616 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
617 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
622 /* Sample standard deviation (s^2) */
623 if (rec->counter <= 1)
627 * Apply Welford's method:
628 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
630 stddev = rec->counter * rec->time_squared -
631 rec->time * rec->time;
634 * Divide only 1000 for ns^2 -> us^2 conversion.
635 * trace_print_graph_duration will divide 1000 again.
637 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
641 trace_print_graph_duration(rec->time, &s);
642 trace_seq_puts(&s, " ");
643 trace_print_graph_duration(avg, &s);
644 trace_seq_puts(&s, " ");
645 trace_print_graph_duration(stddev, &s);
646 trace_print_seq(m, &s);
650 mutex_unlock(&ftrace_profile_lock);
655 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
657 struct ftrace_profile_page *pg;
659 pg = stat->pages = stat->start;
662 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
667 memset(stat->hash, 0,
668 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
671 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
673 struct ftrace_profile_page *pg;
678 /* If we already allocated, do nothing */
682 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
686 #ifdef CONFIG_DYNAMIC_FTRACE
687 functions = ftrace_update_tot_cnt;
690 * We do not know the number of functions that exist because
691 * dynamic tracing is what counts them. With past experience
692 * we have around 20K functions. That should be more than enough.
693 * It is highly unlikely we will execute every function in
699 pg = stat->start = stat->pages;
701 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
703 for (i = 1; i < pages; i++) {
704 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
715 unsigned long tmp = (unsigned long)pg;
727 static int ftrace_profile_init_cpu(int cpu)
729 struct ftrace_profile_stat *stat;
732 stat = &per_cpu(ftrace_profile_stats, cpu);
735 /* If the profile is already created, simply reset it */
736 ftrace_profile_reset(stat);
741 * We are profiling all functions, but usually only a few thousand
742 * functions are hit. We'll make a hash of 1024 items.
744 size = FTRACE_PROFILE_HASH_SIZE;
746 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
751 /* Preallocate the function profiling pages */
752 if (ftrace_profile_pages_init(stat) < 0) {
761 static int ftrace_profile_init(void)
766 for_each_possible_cpu(cpu) {
767 ret = ftrace_profile_init_cpu(cpu);
775 /* interrupts must be disabled */
776 static struct ftrace_profile *
777 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
779 struct ftrace_profile *rec;
780 struct hlist_head *hhd;
783 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
784 hhd = &stat->hash[key];
786 if (hlist_empty(hhd))
789 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
797 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
798 struct ftrace_profile *rec)
802 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
803 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
807 * The memory is already allocated, this simply finds a new record to use.
809 static struct ftrace_profile *
810 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
812 struct ftrace_profile *rec = NULL;
814 /* prevent recursion (from NMIs) */
815 if (atomic_inc_return(&stat->disabled) != 1)
819 * Try to find the function again since an NMI
820 * could have added it
822 rec = ftrace_find_profiled_func(stat, ip);
826 if (stat->pages->index == PROFILES_PER_PAGE) {
827 if (!stat->pages->next)
829 stat->pages = stat->pages->next;
832 rec = &stat->pages->records[stat->pages->index++];
834 ftrace_add_profile(stat, rec);
837 atomic_dec(&stat->disabled);
843 function_profile_call(unsigned long ip, unsigned long parent_ip,
844 struct ftrace_ops *ops, struct pt_regs *regs)
846 struct ftrace_profile_stat *stat;
847 struct ftrace_profile *rec;
850 if (!ftrace_profile_enabled)
853 local_irq_save(flags);
855 stat = this_cpu_ptr(&ftrace_profile_stats);
856 if (!stat->hash || !ftrace_profile_enabled)
859 rec = ftrace_find_profiled_func(stat, ip);
861 rec = ftrace_profile_alloc(stat, ip);
868 local_irq_restore(flags);
871 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
872 static int profile_graph_entry(struct ftrace_graph_ent *trace)
874 function_profile_call(trace->func, 0, NULL, NULL);
878 static void profile_graph_return(struct ftrace_graph_ret *trace)
880 struct ftrace_profile_stat *stat;
881 unsigned long long calltime;
882 struct ftrace_profile *rec;
885 local_irq_save(flags);
886 stat = this_cpu_ptr(&ftrace_profile_stats);
887 if (!stat->hash || !ftrace_profile_enabled)
890 /* If the calltime was zero'd ignore it */
891 if (!trace->calltime)
894 calltime = trace->rettime - trace->calltime;
896 if (!fgraph_graph_time) {
899 index = trace->depth;
901 /* Append this call time to the parent time to subtract */
903 current->ret_stack[index - 1].subtime += calltime;
905 if (current->ret_stack[index].subtime < calltime)
906 calltime -= current->ret_stack[index].subtime;
911 rec = ftrace_find_profiled_func(stat, trace->func);
913 rec->time += calltime;
914 rec->time_squared += calltime * calltime;
918 local_irq_restore(flags);
921 static int register_ftrace_profiler(void)
923 return register_ftrace_graph(&profile_graph_return,
924 &profile_graph_entry);
927 static void unregister_ftrace_profiler(void)
929 unregister_ftrace_graph();
932 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
933 .func = function_profile_call,
934 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
935 INIT_OPS_HASH(ftrace_profile_ops)
938 static int register_ftrace_profiler(void)
940 return register_ftrace_function(&ftrace_profile_ops);
943 static void unregister_ftrace_profiler(void)
945 unregister_ftrace_function(&ftrace_profile_ops);
947 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
950 ftrace_profile_write(struct file *filp, const char __user *ubuf,
951 size_t cnt, loff_t *ppos)
956 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
962 mutex_lock(&ftrace_profile_lock);
963 if (ftrace_profile_enabled ^ val) {
965 ret = ftrace_profile_init();
971 ret = register_ftrace_profiler();
976 ftrace_profile_enabled = 1;
978 ftrace_profile_enabled = 0;
980 * unregister_ftrace_profiler calls stop_machine
981 * so this acts like an synchronize_sched.
983 unregister_ftrace_profiler();
987 mutex_unlock(&ftrace_profile_lock);
995 ftrace_profile_read(struct file *filp, char __user *ubuf,
996 size_t cnt, loff_t *ppos)
998 char buf[64]; /* big enough to hold a number */
1001 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1002 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1005 static const struct file_operations ftrace_profile_fops = {
1006 .open = tracing_open_generic,
1007 .read = ftrace_profile_read,
1008 .write = ftrace_profile_write,
1009 .llseek = default_llseek,
1012 /* used to initialize the real stat files */
1013 static struct tracer_stat function_stats __initdata = {
1014 .name = "functions",
1015 .stat_start = function_stat_start,
1016 .stat_next = function_stat_next,
1017 .stat_cmp = function_stat_cmp,
1018 .stat_headers = function_stat_headers,
1019 .stat_show = function_stat_show
1022 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1024 struct ftrace_profile_stat *stat;
1025 struct dentry *entry;
1030 for_each_possible_cpu(cpu) {
1031 stat = &per_cpu(ftrace_profile_stats, cpu);
1033 /* allocate enough for function name + cpu number */
1034 name = kmalloc(32, GFP_KERNEL);
1037 * The files created are permanent, if something happens
1038 * we still do not free memory.
1041 "Could not allocate stat file for cpu %d\n",
1045 stat->stat = function_stats;
1046 snprintf(name, 32, "function%d", cpu);
1047 stat->stat.name = name;
1048 ret = register_stat_tracer(&stat->stat);
1051 "Could not register function stat for cpu %d\n",
1058 entry = tracefs_create_file("function_profile_enabled", 0644,
1059 d_tracer, NULL, &ftrace_profile_fops);
1061 pr_warning("Could not create tracefs "
1062 "'function_profile_enabled' entry\n");
1065 #else /* CONFIG_FUNCTION_PROFILER */
1066 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1069 #endif /* CONFIG_FUNCTION_PROFILER */
1071 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1073 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1074 static int ftrace_graph_active;
1076 # define ftrace_graph_active 0
1079 #ifdef CONFIG_DYNAMIC_FTRACE
1081 static struct ftrace_ops *removed_ops;
1084 * Set when doing a global update, like enabling all recs or disabling them.
1085 * It is not set when just updating a single ftrace_ops.
1087 static bool update_all_ops;
1089 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1090 # error Dynamic ftrace depends on MCOUNT_RECORD
1093 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1095 struct ftrace_func_probe {
1096 struct hlist_node node;
1097 struct ftrace_probe_ops *ops;
1098 unsigned long flags;
1101 struct list_head free_list;
1104 struct ftrace_func_entry {
1105 struct hlist_node hlist;
1109 struct ftrace_hash {
1110 unsigned long size_bits;
1111 struct hlist_head *buckets;
1112 unsigned long count;
1113 struct rcu_head rcu;
1117 * We make these constant because no one should touch them,
1118 * but they are used as the default "empty hash", to avoid allocating
1119 * it all the time. These are in a read only section such that if
1120 * anyone does try to modify it, it will cause an exception.
1122 static const struct hlist_head empty_buckets[1];
1123 static const struct ftrace_hash empty_hash = {
1124 .buckets = (struct hlist_head *)empty_buckets,
1126 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1128 static struct ftrace_ops global_ops = {
1129 .func = ftrace_stub,
1130 .local_hash.notrace_hash = EMPTY_HASH,
1131 .local_hash.filter_hash = EMPTY_HASH,
1132 INIT_OPS_HASH(global_ops)
1133 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
1134 FTRACE_OPS_FL_INITIALIZED |
1139 * This is used by __kernel_text_address() to return true if the
1140 * address is on a dynamically allocated trampoline that would
1141 * not return true for either core_kernel_text() or
1142 * is_module_text_address().
1144 bool is_ftrace_trampoline(unsigned long addr)
1146 struct ftrace_ops *op;
1150 * Some of the ops may be dynamically allocated,
1151 * they are freed after a synchronize_sched().
1153 preempt_disable_notrace();
1155 do_for_each_ftrace_op(op, ftrace_ops_list) {
1157 * This is to check for dynamically allocated trampolines.
1158 * Trampolines that are in kernel text will have
1159 * core_kernel_text() return true.
1161 if (op->trampoline && op->trampoline_size)
1162 if (addr >= op->trampoline &&
1163 addr < op->trampoline + op->trampoline_size) {
1167 } while_for_each_ftrace_op(op);
1170 preempt_enable_notrace();
1175 struct ftrace_page {
1176 struct ftrace_page *next;
1177 struct dyn_ftrace *records;
1182 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1183 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1185 /* estimate from running different kernels */
1186 #define NR_TO_INIT 10000
1188 static struct ftrace_page *ftrace_pages_start;
1189 static struct ftrace_page *ftrace_pages;
1191 static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1193 return !hash || !hash->count;
1196 static struct ftrace_func_entry *
1197 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1200 struct ftrace_func_entry *entry;
1201 struct hlist_head *hhd;
1203 if (ftrace_hash_empty(hash))
1206 if (hash->size_bits > 0)
1207 key = hash_long(ip, hash->size_bits);
1211 hhd = &hash->buckets[key];
1213 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1214 if (entry->ip == ip)
1220 static void __add_hash_entry(struct ftrace_hash *hash,
1221 struct ftrace_func_entry *entry)
1223 struct hlist_head *hhd;
1226 if (hash->size_bits)
1227 key = hash_long(entry->ip, hash->size_bits);
1231 hhd = &hash->buckets[key];
1232 hlist_add_head(&entry->hlist, hhd);
1236 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1238 struct ftrace_func_entry *entry;
1240 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1245 __add_hash_entry(hash, entry);
1251 free_hash_entry(struct ftrace_hash *hash,
1252 struct ftrace_func_entry *entry)
1254 hlist_del(&entry->hlist);
1260 remove_hash_entry(struct ftrace_hash *hash,
1261 struct ftrace_func_entry *entry)
1263 hlist_del(&entry->hlist);
1267 static void ftrace_hash_clear(struct ftrace_hash *hash)
1269 struct hlist_head *hhd;
1270 struct hlist_node *tn;
1271 struct ftrace_func_entry *entry;
1272 int size = 1 << hash->size_bits;
1278 for (i = 0; i < size; i++) {
1279 hhd = &hash->buckets[i];
1280 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1281 free_hash_entry(hash, entry);
1283 FTRACE_WARN_ON(hash->count);
1286 static void free_ftrace_hash(struct ftrace_hash *hash)
1288 if (!hash || hash == EMPTY_HASH)
1290 ftrace_hash_clear(hash);
1291 kfree(hash->buckets);
1295 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1297 struct ftrace_hash *hash;
1299 hash = container_of(rcu, struct ftrace_hash, rcu);
1300 free_ftrace_hash(hash);
1303 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1305 if (!hash || hash == EMPTY_HASH)
1307 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1310 void ftrace_free_filter(struct ftrace_ops *ops)
1312 ftrace_ops_init(ops);
1313 free_ftrace_hash(ops->func_hash->filter_hash);
1314 free_ftrace_hash(ops->func_hash->notrace_hash);
1317 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1319 struct ftrace_hash *hash;
1322 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1326 size = 1 << size_bits;
1327 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1329 if (!hash->buckets) {
1334 hash->size_bits = size_bits;
1339 static struct ftrace_hash *
1340 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1342 struct ftrace_func_entry *entry;
1343 struct ftrace_hash *new_hash;
1348 new_hash = alloc_ftrace_hash(size_bits);
1353 if (ftrace_hash_empty(hash))
1356 size = 1 << hash->size_bits;
1357 for (i = 0; i < size; i++) {
1358 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1359 ret = add_hash_entry(new_hash, entry->ip);
1365 FTRACE_WARN_ON(new_hash->count != hash->count);
1370 free_ftrace_hash(new_hash);
1375 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1377 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1379 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1380 struct ftrace_hash *new_hash);
1383 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1384 struct ftrace_hash **dst, struct ftrace_hash *src)
1386 struct ftrace_func_entry *entry;
1387 struct hlist_node *tn;
1388 struct hlist_head *hhd;
1389 struct ftrace_hash *new_hash;
1390 int size = src->count;
1395 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1396 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1400 * If the new source is empty, just free dst and assign it
1404 new_hash = EMPTY_HASH;
1409 * Make the hash size about 1/2 the # found
1411 for (size /= 2; size; size >>= 1)
1414 /* Don't allocate too much */
1415 if (bits > FTRACE_HASH_MAX_BITS)
1416 bits = FTRACE_HASH_MAX_BITS;
1418 new_hash = alloc_ftrace_hash(bits);
1422 size = 1 << src->size_bits;
1423 for (i = 0; i < size; i++) {
1424 hhd = &src->buckets[i];
1425 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1426 remove_hash_entry(src, entry);
1427 __add_hash_entry(new_hash, entry);
1432 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1434 /* IPMODIFY should be updated only when filter_hash updating */
1435 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1437 free_ftrace_hash(new_hash);
1443 * Remove the current set, update the hash and add
1446 ftrace_hash_rec_disable_modify(ops, enable);
1448 rcu_assign_pointer(*dst, new_hash);
1450 ftrace_hash_rec_enable_modify(ops, enable);
1455 static bool hash_contains_ip(unsigned long ip,
1456 struct ftrace_ops_hash *hash)
1459 * The function record is a match if it exists in the filter
1460 * hash and not in the notrace hash. Note, an emty hash is
1461 * considered a match for the filter hash, but an empty
1462 * notrace hash is considered not in the notrace hash.
1464 return (ftrace_hash_empty(hash->filter_hash) ||
1465 ftrace_lookup_ip(hash->filter_hash, ip)) &&
1466 (ftrace_hash_empty(hash->notrace_hash) ||
1467 !ftrace_lookup_ip(hash->notrace_hash, ip));
1471 * Test the hashes for this ops to see if we want to call
1472 * the ops->func or not.
1474 * It's a match if the ip is in the ops->filter_hash or
1475 * the filter_hash does not exist or is empty,
1477 * the ip is not in the ops->notrace_hash.
1479 * This needs to be called with preemption disabled as
1480 * the hashes are freed with call_rcu_sched().
1483 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1485 struct ftrace_ops_hash hash;
1488 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1490 * There's a small race when adding ops that the ftrace handler
1491 * that wants regs, may be called without them. We can not
1492 * allow that handler to be called if regs is NULL.
1494 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1498 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1499 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1501 if (hash_contains_ip(ip, &hash))
1510 * This is a double for. Do not use 'break' to break out of the loop,
1511 * you must use a goto.
1513 #define do_for_each_ftrace_rec(pg, rec) \
1514 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1516 for (_____i = 0; _____i < pg->index; _____i++) { \
1517 rec = &pg->records[_____i];
1519 #define while_for_each_ftrace_rec() \
1524 static int ftrace_cmp_recs(const void *a, const void *b)
1526 const struct dyn_ftrace *key = a;
1527 const struct dyn_ftrace *rec = b;
1529 if (key->flags < rec->ip)
1531 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1537 * ftrace_location_range - return the first address of a traced location
1538 * if it touches the given ip range
1539 * @start: start of range to search.
1540 * @end: end of range to search (inclusive). @end points to the last byte
1543 * Returns rec->ip if the related ftrace location is a least partly within
1544 * the given address range. That is, the first address of the instruction
1545 * that is either a NOP or call to the function tracer. It checks the ftrace
1546 * internal tables to determine if the address belongs or not.
1548 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1550 struct ftrace_page *pg;
1551 struct dyn_ftrace *rec;
1552 struct dyn_ftrace key;
1555 key.flags = end; /* overload flags, as it is unsigned long */
1557 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1558 if (end < pg->records[0].ip ||
1559 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1561 rec = bsearch(&key, pg->records, pg->index,
1562 sizeof(struct dyn_ftrace),
1572 * ftrace_location - return true if the ip giving is a traced location
1573 * @ip: the instruction pointer to check
1575 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1576 * That is, the instruction that is either a NOP or call to
1577 * the function tracer. It checks the ftrace internal tables to
1578 * determine if the address belongs or not.
1580 unsigned long ftrace_location(unsigned long ip)
1582 return ftrace_location_range(ip, ip);
1586 * ftrace_text_reserved - return true if range contains an ftrace location
1587 * @start: start of range to search
1588 * @end: end of range to search (inclusive). @end points to the last byte to check.
1590 * Returns 1 if @start and @end contains a ftrace location.
1591 * That is, the instruction that is either a NOP or call to
1592 * the function tracer. It checks the ftrace internal tables to
1593 * determine if the address belongs or not.
1595 int ftrace_text_reserved(const void *start, const void *end)
1599 ret = ftrace_location_range((unsigned long)start,
1600 (unsigned long)end);
1605 /* Test if ops registered to this rec needs regs */
1606 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1608 struct ftrace_ops *ops;
1609 bool keep_regs = false;
1611 for (ops = ftrace_ops_list;
1612 ops != &ftrace_list_end; ops = ops->next) {
1613 /* pass rec in as regs to have non-NULL val */
1614 if (ftrace_ops_test(ops, rec->ip, rec)) {
1615 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1625 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1629 struct ftrace_hash *hash;
1630 struct ftrace_hash *other_hash;
1631 struct ftrace_page *pg;
1632 struct dyn_ftrace *rec;
1636 /* Only update if the ops has been registered */
1637 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1641 * In the filter_hash case:
1642 * If the count is zero, we update all records.
1643 * Otherwise we just update the items in the hash.
1645 * In the notrace_hash case:
1646 * We enable the update in the hash.
1647 * As disabling notrace means enabling the tracing,
1648 * and enabling notrace means disabling, the inc variable
1652 hash = ops->func_hash->filter_hash;
1653 other_hash = ops->func_hash->notrace_hash;
1654 if (ftrace_hash_empty(hash))
1658 hash = ops->func_hash->notrace_hash;
1659 other_hash = ops->func_hash->filter_hash;
1661 * If the notrace hash has no items,
1662 * then there's nothing to do.
1664 if (ftrace_hash_empty(hash))
1668 do_for_each_ftrace_rec(pg, rec) {
1669 int in_other_hash = 0;
1673 if (rec->flags & FTRACE_FL_DISABLED)
1678 * Only the filter_hash affects all records.
1679 * Update if the record is not in the notrace hash.
1681 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1684 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1685 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1688 * If filter_hash is set, we want to match all functions
1689 * that are in the hash but not in the other hash.
1691 * If filter_hash is not set, then we are decrementing.
1692 * That means we match anything that is in the hash
1693 * and also in the other_hash. That is, we need to turn
1694 * off functions in the other hash because they are disabled
1697 if (filter_hash && in_hash && !in_other_hash)
1699 else if (!filter_hash && in_hash &&
1700 (in_other_hash || ftrace_hash_empty(other_hash)))
1708 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1712 * If there's only a single callback registered to a
1713 * function, and the ops has a trampoline registered
1714 * for it, then we can call it directly.
1716 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1717 rec->flags |= FTRACE_FL_TRAMP;
1720 * If we are adding another function callback
1721 * to this function, and the previous had a
1722 * custom trampoline in use, then we need to go
1723 * back to the default trampoline.
1725 rec->flags &= ~FTRACE_FL_TRAMP;
1728 * If any ops wants regs saved for this function
1729 * then all ops will get saved regs.
1731 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1732 rec->flags |= FTRACE_FL_REGS;
1734 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1739 * If the rec had REGS enabled and the ops that is
1740 * being removed had REGS set, then see if there is
1741 * still any ops for this record that wants regs.
1742 * If not, we can stop recording them.
1744 if (ftrace_rec_count(rec) > 0 &&
1745 rec->flags & FTRACE_FL_REGS &&
1746 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1747 if (!test_rec_ops_needs_regs(rec))
1748 rec->flags &= ~FTRACE_FL_REGS;
1752 * If the rec had TRAMP enabled, then it needs to
1753 * be cleared. As TRAMP can only be enabled iff
1754 * there is only a single ops attached to it.
1755 * In otherwords, always disable it on decrementing.
1756 * In the future, we may set it if rec count is
1757 * decremented to one, and the ops that is left
1760 rec->flags &= ~FTRACE_FL_TRAMP;
1763 * flags will be cleared in ftrace_check_record()
1764 * if rec count is zero.
1768 /* Shortcut, if we handled all records, we are done. */
1769 if (!all && count == hash->count)
1771 } while_for_each_ftrace_rec();
1774 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1777 __ftrace_hash_rec_update(ops, filter_hash, 0);
1780 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1783 __ftrace_hash_rec_update(ops, filter_hash, 1);
1786 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1787 int filter_hash, int inc)
1789 struct ftrace_ops *op;
1791 __ftrace_hash_rec_update(ops, filter_hash, inc);
1793 if (ops->func_hash != &global_ops.local_hash)
1797 * If the ops shares the global_ops hash, then we need to update
1798 * all ops that are enabled and use this hash.
1800 do_for_each_ftrace_op(op, ftrace_ops_list) {
1804 if (op->func_hash == &global_ops.local_hash)
1805 __ftrace_hash_rec_update(op, filter_hash, inc);
1806 } while_for_each_ftrace_op(op);
1809 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1812 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1815 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1818 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1822 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1823 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1824 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1825 * Note that old_hash and new_hash has below meanings
1826 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1827 * - If the hash is EMPTY_HASH, it hits nothing
1828 * - Anything else hits the recs which match the hash entries.
1830 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1831 struct ftrace_hash *old_hash,
1832 struct ftrace_hash *new_hash)
1834 struct ftrace_page *pg;
1835 struct dyn_ftrace *rec, *end = NULL;
1838 /* Only update if the ops has been registered */
1839 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1842 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1846 * Since the IPMODIFY is a very address sensitive action, we do not
1847 * allow ftrace_ops to set all functions to new hash.
1849 if (!new_hash || !old_hash)
1852 /* Update rec->flags */
1853 do_for_each_ftrace_rec(pg, rec) {
1854 /* We need to update only differences of filter_hash */
1855 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1856 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1857 if (in_old == in_new)
1861 /* New entries must ensure no others are using it */
1862 if (rec->flags & FTRACE_FL_IPMODIFY)
1864 rec->flags |= FTRACE_FL_IPMODIFY;
1865 } else /* Removed entry */
1866 rec->flags &= ~FTRACE_FL_IPMODIFY;
1867 } while_for_each_ftrace_rec();
1874 /* Roll back what we did above */
1875 do_for_each_ftrace_rec(pg, rec) {
1879 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1880 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1881 if (in_old == in_new)
1885 rec->flags &= ~FTRACE_FL_IPMODIFY;
1887 rec->flags |= FTRACE_FL_IPMODIFY;
1888 } while_for_each_ftrace_rec();
1894 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1896 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1898 if (ftrace_hash_empty(hash))
1901 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1904 /* Disabling always succeeds */
1905 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1907 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1909 if (ftrace_hash_empty(hash))
1912 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1915 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1916 struct ftrace_hash *new_hash)
1918 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1920 if (ftrace_hash_empty(old_hash))
1923 if (ftrace_hash_empty(new_hash))
1926 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1929 static void print_ip_ins(const char *fmt, const unsigned char *p)
1933 printk(KERN_CONT "%s", fmt);
1935 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1936 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1939 static struct ftrace_ops *
1940 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1941 static struct ftrace_ops *
1942 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1944 enum ftrace_bug_type ftrace_bug_type;
1945 const void *ftrace_expected;
1947 static void print_bug_type(void)
1949 switch (ftrace_bug_type) {
1950 case FTRACE_BUG_UNKNOWN:
1952 case FTRACE_BUG_INIT:
1953 pr_info("Initializing ftrace call sites\n");
1955 case FTRACE_BUG_NOP:
1956 pr_info("Setting ftrace call site to NOP\n");
1958 case FTRACE_BUG_CALL:
1959 pr_info("Setting ftrace call site to call ftrace function\n");
1961 case FTRACE_BUG_UPDATE:
1962 pr_info("Updating ftrace call site to call a different ftrace function\n");
1968 * ftrace_bug - report and shutdown function tracer
1969 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1970 * @rec: The record that failed
1972 * The arch code that enables or disables the function tracing
1973 * can call ftrace_bug() when it has detected a problem in
1974 * modifying the code. @failed should be one of either:
1975 * EFAULT - if the problem happens on reading the @ip address
1976 * EINVAL - if what is read at @ip is not what was expected
1977 * EPERM - if the problem happens on writting to the @ip address
1979 void ftrace_bug(int failed, struct dyn_ftrace *rec)
1981 unsigned long ip = rec ? rec->ip : 0;
1985 FTRACE_WARN_ON_ONCE(1);
1986 pr_info("ftrace faulted on modifying ");
1990 FTRACE_WARN_ON_ONCE(1);
1991 pr_info("ftrace failed to modify ");
1993 print_ip_ins(" actual: ", (unsigned char *)ip);
1995 if (ftrace_expected) {
1996 print_ip_ins(" expected: ", ftrace_expected);
2001 FTRACE_WARN_ON_ONCE(1);
2002 pr_info("ftrace faulted on writing ");
2006 FTRACE_WARN_ON_ONCE(1);
2007 pr_info("ftrace faulted on unknown error ");
2012 struct ftrace_ops *ops = NULL;
2014 pr_info("ftrace record flags: %lx\n", rec->flags);
2015 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2016 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2017 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2018 ops = ftrace_find_tramp_ops_any(rec);
2021 pr_cont("\ttramp: %pS (%pS)",
2022 (void *)ops->trampoline,
2024 ops = ftrace_find_tramp_ops_next(rec, ops);
2027 pr_cont("\ttramp: ERROR!");
2030 ip = ftrace_get_addr_curr(rec);
2031 pr_cont("\n expected tramp: %lx\n", ip);
2035 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2037 unsigned long flag = 0UL;
2039 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2041 if (rec->flags & FTRACE_FL_DISABLED)
2042 return FTRACE_UPDATE_IGNORE;
2045 * If we are updating calls:
2047 * If the record has a ref count, then we need to enable it
2048 * because someone is using it.
2050 * Otherwise we make sure its disabled.
2052 * If we are disabling calls, then disable all records that
2055 if (enable && ftrace_rec_count(rec))
2056 flag = FTRACE_FL_ENABLED;
2059 * If enabling and the REGS flag does not match the REGS_EN, or
2060 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2061 * this record. Set flags to fail the compare against ENABLED.
2064 if (!(rec->flags & FTRACE_FL_REGS) !=
2065 !(rec->flags & FTRACE_FL_REGS_EN))
2066 flag |= FTRACE_FL_REGS;
2068 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2069 !(rec->flags & FTRACE_FL_TRAMP_EN))
2070 flag |= FTRACE_FL_TRAMP;
2073 /* If the state of this record hasn't changed, then do nothing */
2074 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2075 return FTRACE_UPDATE_IGNORE;
2078 /* Save off if rec is being enabled (for return value) */
2079 flag ^= rec->flags & FTRACE_FL_ENABLED;
2082 rec->flags |= FTRACE_FL_ENABLED;
2083 if (flag & FTRACE_FL_REGS) {
2084 if (rec->flags & FTRACE_FL_REGS)
2085 rec->flags |= FTRACE_FL_REGS_EN;
2087 rec->flags &= ~FTRACE_FL_REGS_EN;
2089 if (flag & FTRACE_FL_TRAMP) {
2090 if (rec->flags & FTRACE_FL_TRAMP)
2091 rec->flags |= FTRACE_FL_TRAMP_EN;
2093 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2098 * If this record is being updated from a nop, then
2099 * return UPDATE_MAKE_CALL.
2101 * return UPDATE_MODIFY_CALL to tell the caller to convert
2102 * from the save regs, to a non-save regs function or
2103 * vice versa, or from a trampoline call.
2105 if (flag & FTRACE_FL_ENABLED) {
2106 ftrace_bug_type = FTRACE_BUG_CALL;
2107 return FTRACE_UPDATE_MAKE_CALL;
2110 ftrace_bug_type = FTRACE_BUG_UPDATE;
2111 return FTRACE_UPDATE_MODIFY_CALL;
2115 /* If there's no more users, clear all flags */
2116 if (!ftrace_rec_count(rec))
2120 * Just disable the record, but keep the ops TRAMP
2121 * and REGS states. The _EN flags must be disabled though.
2123 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2127 ftrace_bug_type = FTRACE_BUG_NOP;
2128 return FTRACE_UPDATE_MAKE_NOP;
2132 * ftrace_update_record, set a record that now is tracing or not
2133 * @rec: the record to update
2134 * @enable: set to 1 if the record is tracing, zero to force disable
2136 * The records that represent all functions that can be traced need
2137 * to be updated when tracing has been enabled.
2139 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2141 return ftrace_check_record(rec, enable, 1);
2145 * ftrace_test_record, check if the record has been enabled or not
2146 * @rec: the record to test
2147 * @enable: set to 1 to check if enabled, 0 if it is disabled
2149 * The arch code may need to test if a record is already set to
2150 * tracing to determine how to modify the function code that it
2153 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2155 return ftrace_check_record(rec, enable, 0);
2158 static struct ftrace_ops *
2159 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2161 struct ftrace_ops *op;
2162 unsigned long ip = rec->ip;
2164 do_for_each_ftrace_op(op, ftrace_ops_list) {
2166 if (!op->trampoline)
2169 if (hash_contains_ip(ip, op->func_hash))
2171 } while_for_each_ftrace_op(op);
2176 static struct ftrace_ops *
2177 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2178 struct ftrace_ops *op)
2180 unsigned long ip = rec->ip;
2182 while_for_each_ftrace_op(op) {
2184 if (!op->trampoline)
2187 if (hash_contains_ip(ip, op->func_hash))
2194 static struct ftrace_ops *
2195 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2197 struct ftrace_ops *op;
2198 unsigned long ip = rec->ip;
2201 * Need to check removed ops first.
2202 * If they are being removed, and this rec has a tramp,
2203 * and this rec is in the ops list, then it would be the
2204 * one with the tramp.
2207 if (hash_contains_ip(ip, &removed_ops->old_hash))
2212 * Need to find the current trampoline for a rec.
2213 * Now, a trampoline is only attached to a rec if there
2214 * was a single 'ops' attached to it. But this can be called
2215 * when we are adding another op to the rec or removing the
2216 * current one. Thus, if the op is being added, we can
2217 * ignore it because it hasn't attached itself to the rec
2220 * If an ops is being modified (hooking to different functions)
2221 * then we don't care about the new functions that are being
2222 * added, just the old ones (that are probably being removed).
2224 * If we are adding an ops to a function that already is using
2225 * a trampoline, it needs to be removed (trampolines are only
2226 * for single ops connected), then an ops that is not being
2227 * modified also needs to be checked.
2229 do_for_each_ftrace_op(op, ftrace_ops_list) {
2231 if (!op->trampoline)
2235 * If the ops is being added, it hasn't gotten to
2236 * the point to be removed from this tree yet.
2238 if (op->flags & FTRACE_OPS_FL_ADDING)
2243 * If the ops is being modified and is in the old
2244 * hash, then it is probably being removed from this
2247 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2248 hash_contains_ip(ip, &op->old_hash))
2251 * If the ops is not being added or modified, and it's
2252 * in its normal filter hash, then this must be the one
2255 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2256 hash_contains_ip(ip, op->func_hash))
2259 } while_for_each_ftrace_op(op);
2264 static struct ftrace_ops *
2265 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2267 struct ftrace_ops *op;
2268 unsigned long ip = rec->ip;
2270 do_for_each_ftrace_op(op, ftrace_ops_list) {
2271 /* pass rec in as regs to have non-NULL val */
2272 if (hash_contains_ip(ip, op->func_hash))
2274 } while_for_each_ftrace_op(op);
2280 * ftrace_get_addr_new - Get the call address to set to
2281 * @rec: The ftrace record descriptor
2283 * If the record has the FTRACE_FL_REGS set, that means that it
2284 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2285 * is not not set, then it wants to convert to the normal callback.
2287 * Returns the address of the trampoline to set to
2289 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2291 struct ftrace_ops *ops;
2293 /* Trampolines take precedence over regs */
2294 if (rec->flags & FTRACE_FL_TRAMP) {
2295 ops = ftrace_find_tramp_ops_new(rec);
2296 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2297 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2298 (void *)rec->ip, (void *)rec->ip, rec->flags);
2299 /* Ftrace is shutting down, return anything */
2300 return (unsigned long)FTRACE_ADDR;
2302 return ops->trampoline;
2305 if (rec->flags & FTRACE_FL_REGS)
2306 return (unsigned long)FTRACE_REGS_ADDR;
2308 return (unsigned long)FTRACE_ADDR;
2312 * ftrace_get_addr_curr - Get the call address that is already there
2313 * @rec: The ftrace record descriptor
2315 * The FTRACE_FL_REGS_EN is set when the record already points to
2316 * a function that saves all the regs. Basically the '_EN' version
2317 * represents the current state of the function.
2319 * Returns the address of the trampoline that is currently being called
2321 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2323 struct ftrace_ops *ops;
2325 /* Trampolines take precedence over regs */
2326 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2327 ops = ftrace_find_tramp_ops_curr(rec);
2328 if (FTRACE_WARN_ON(!ops)) {
2329 pr_warning("Bad trampoline accounting at: %p (%pS)\n",
2330 (void *)rec->ip, (void *)rec->ip);
2331 /* Ftrace is shutting down, return anything */
2332 return (unsigned long)FTRACE_ADDR;
2334 return ops->trampoline;
2337 if (rec->flags & FTRACE_FL_REGS_EN)
2338 return (unsigned long)FTRACE_REGS_ADDR;
2340 return (unsigned long)FTRACE_ADDR;
2344 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2346 unsigned long ftrace_old_addr;
2347 unsigned long ftrace_addr;
2350 ftrace_addr = ftrace_get_addr_new(rec);
2352 /* This needs to be done before we call ftrace_update_record */
2353 ftrace_old_addr = ftrace_get_addr_curr(rec);
2355 ret = ftrace_update_record(rec, enable);
2357 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2360 case FTRACE_UPDATE_IGNORE:
2363 case FTRACE_UPDATE_MAKE_CALL:
2364 ftrace_bug_type = FTRACE_BUG_CALL;
2365 return ftrace_make_call(rec, ftrace_addr);
2367 case FTRACE_UPDATE_MAKE_NOP:
2368 ftrace_bug_type = FTRACE_BUG_NOP;
2369 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2371 case FTRACE_UPDATE_MODIFY_CALL:
2372 ftrace_bug_type = FTRACE_BUG_UPDATE;
2373 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2376 return -1; /* unknow ftrace bug */
2379 void __weak ftrace_replace_code(int enable)
2381 struct dyn_ftrace *rec;
2382 struct ftrace_page *pg;
2385 if (unlikely(ftrace_disabled))
2388 do_for_each_ftrace_rec(pg, rec) {
2389 failed = __ftrace_replace_code(rec, enable);
2391 ftrace_bug(failed, rec);
2392 /* Stop processing */
2395 } while_for_each_ftrace_rec();
2398 struct ftrace_rec_iter {
2399 struct ftrace_page *pg;
2404 * ftrace_rec_iter_start, start up iterating over traced functions
2406 * Returns an iterator handle that is used to iterate over all
2407 * the records that represent address locations where functions
2410 * May return NULL if no records are available.
2412 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2415 * We only use a single iterator.
2416 * Protected by the ftrace_lock mutex.
2418 static struct ftrace_rec_iter ftrace_rec_iter;
2419 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2421 iter->pg = ftrace_pages_start;
2424 /* Could have empty pages */
2425 while (iter->pg && !iter->pg->index)
2426 iter->pg = iter->pg->next;
2435 * ftrace_rec_iter_next, get the next record to process.
2436 * @iter: The handle to the iterator.
2438 * Returns the next iterator after the given iterator @iter.
2440 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2444 if (iter->index >= iter->pg->index) {
2445 iter->pg = iter->pg->next;
2448 /* Could have empty pages */
2449 while (iter->pg && !iter->pg->index)
2450 iter->pg = iter->pg->next;
2460 * ftrace_rec_iter_record, get the record at the iterator location
2461 * @iter: The current iterator location
2463 * Returns the record that the current @iter is at.
2465 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2467 return &iter->pg->records[iter->index];
2471 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2475 if (unlikely(ftrace_disabled))
2478 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2480 ftrace_bug_type = FTRACE_BUG_INIT;
2481 ftrace_bug(ret, rec);
2488 * archs can override this function if they must do something
2489 * before the modifying code is performed.
2491 int __weak ftrace_arch_code_modify_prepare(void)
2497 * archs can override this function if they must do something
2498 * after the modifying code is performed.
2500 int __weak ftrace_arch_code_modify_post_process(void)
2505 void ftrace_modify_all_code(int command)
2507 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2511 * If the ftrace_caller calls a ftrace_ops func directly,
2512 * we need to make sure that it only traces functions it
2513 * expects to trace. When doing the switch of functions,
2514 * we need to update to the ftrace_ops_list_func first
2515 * before the transition between old and new calls are set,
2516 * as the ftrace_ops_list_func will check the ops hashes
2517 * to make sure the ops are having the right functions
2521 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2522 if (FTRACE_WARN_ON(err))
2526 if (command & FTRACE_UPDATE_CALLS)
2527 ftrace_replace_code(1);
2528 else if (command & FTRACE_DISABLE_CALLS)
2529 ftrace_replace_code(0);
2531 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2532 function_trace_op = set_function_trace_op;
2534 /* If irqs are disabled, we are in stop machine */
2535 if (!irqs_disabled())
2536 smp_call_function(ftrace_sync_ipi, NULL, 1);
2537 err = ftrace_update_ftrace_func(ftrace_trace_function);
2538 if (FTRACE_WARN_ON(err))
2542 if (command & FTRACE_START_FUNC_RET)
2543 err = ftrace_enable_ftrace_graph_caller();
2544 else if (command & FTRACE_STOP_FUNC_RET)
2545 err = ftrace_disable_ftrace_graph_caller();
2546 FTRACE_WARN_ON(err);
2549 static int __ftrace_modify_code(void *data)
2551 int *command = data;
2553 ftrace_modify_all_code(*command);
2559 * ftrace_run_stop_machine, go back to the stop machine method
2560 * @command: The command to tell ftrace what to do
2562 * If an arch needs to fall back to the stop machine method, the
2563 * it can call this function.
2565 void ftrace_run_stop_machine(int command)
2567 stop_machine(__ftrace_modify_code, &command, NULL);
2571 * arch_ftrace_update_code, modify the code to trace or not trace
2572 * @command: The command that needs to be done
2574 * Archs can override this function if it does not need to
2575 * run stop_machine() to modify code.
2577 void __weak arch_ftrace_update_code(int command)
2579 ftrace_run_stop_machine(command);
2582 static void ftrace_run_update_code(int command)
2586 ret = ftrace_arch_code_modify_prepare();
2587 FTRACE_WARN_ON(ret);
2592 * By default we use stop_machine() to modify the code.
2593 * But archs can do what ever they want as long as it
2594 * is safe. The stop_machine() is the safest, but also
2595 * produces the most overhead.
2597 arch_ftrace_update_code(command);
2599 ret = ftrace_arch_code_modify_post_process();
2600 FTRACE_WARN_ON(ret);
2603 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2604 struct ftrace_ops_hash *old_hash)
2606 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2607 ops->old_hash.filter_hash = old_hash->filter_hash;
2608 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2609 ftrace_run_update_code(command);
2610 ops->old_hash.filter_hash = NULL;
2611 ops->old_hash.notrace_hash = NULL;
2612 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2615 static ftrace_func_t saved_ftrace_func;
2616 static int ftrace_start_up;
2618 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2622 static void per_cpu_ops_free(struct ftrace_ops *ops)
2624 free_percpu(ops->disabled);
2627 static void ftrace_startup_enable(int command)
2629 if (saved_ftrace_func != ftrace_trace_function) {
2630 saved_ftrace_func = ftrace_trace_function;
2631 command |= FTRACE_UPDATE_TRACE_FUNC;
2634 if (!command || !ftrace_enabled)
2637 ftrace_run_update_code(command);
2640 static void ftrace_startup_all(int command)
2642 update_all_ops = true;
2643 ftrace_startup_enable(command);
2644 update_all_ops = false;
2647 static int ftrace_startup(struct ftrace_ops *ops, int command)
2651 if (unlikely(ftrace_disabled))
2654 ret = __register_ftrace_function(ops);
2659 command |= FTRACE_UPDATE_CALLS;
2662 * Note that ftrace probes uses this to start up
2663 * and modify functions it will probe. But we still
2664 * set the ADDING flag for modification, as probes
2665 * do not have trampolines. If they add them in the
2666 * future, then the probes will need to distinguish
2667 * between adding and updating probes.
2669 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2671 ret = ftrace_hash_ipmodify_enable(ops);
2673 /* Rollback registration process */
2674 __unregister_ftrace_function(ops);
2676 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2680 ftrace_hash_rec_enable(ops, 1);
2682 ftrace_startup_enable(command);
2684 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2689 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2693 if (unlikely(ftrace_disabled))
2696 ret = __unregister_ftrace_function(ops);
2702 * Just warn in case of unbalance, no need to kill ftrace, it's not
2703 * critical but the ftrace_call callers may be never nopped again after
2704 * further ftrace uses.
2706 WARN_ON_ONCE(ftrace_start_up < 0);
2708 /* Disabling ipmodify never fails */
2709 ftrace_hash_ipmodify_disable(ops);
2710 ftrace_hash_rec_disable(ops, 1);
2712 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2714 command |= FTRACE_UPDATE_CALLS;
2716 if (saved_ftrace_func != ftrace_trace_function) {
2717 saved_ftrace_func = ftrace_trace_function;
2718 command |= FTRACE_UPDATE_TRACE_FUNC;
2721 if (!command || !ftrace_enabled) {
2723 * If these are per_cpu ops, they still need their
2724 * per_cpu field freed. Since, function tracing is
2725 * not currently active, we can just free them
2726 * without synchronizing all CPUs.
2728 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2729 per_cpu_ops_free(ops);
2734 * If the ops uses a trampoline, then it needs to be
2735 * tested first on update.
2737 ops->flags |= FTRACE_OPS_FL_REMOVING;
2740 /* The trampoline logic checks the old hashes */
2741 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2742 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2744 ftrace_run_update_code(command);
2747 * If there's no more ops registered with ftrace, run a
2748 * sanity check to make sure all rec flags are cleared.
2750 if (ftrace_ops_list == &ftrace_list_end) {
2751 struct ftrace_page *pg;
2752 struct dyn_ftrace *rec;
2754 do_for_each_ftrace_rec(pg, rec) {
2755 if (FTRACE_WARN_ON_ONCE(rec->flags))
2756 pr_warn(" %pS flags:%lx\n",
2757 (void *)rec->ip, rec->flags);
2758 } while_for_each_ftrace_rec();
2761 ops->old_hash.filter_hash = NULL;
2762 ops->old_hash.notrace_hash = NULL;
2765 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2768 * Dynamic ops may be freed, we must make sure that all
2769 * callers are done before leaving this function.
2770 * The same goes for freeing the per_cpu data of the per_cpu
2773 * Again, normal synchronize_sched() is not good enough.
2774 * We need to do a hard force of sched synchronization.
2775 * This is because we use preempt_disable() to do RCU, but
2776 * the function tracers can be called where RCU is not watching
2777 * (like before user_exit()). We can not rely on the RCU
2778 * infrastructure to do the synchronization, thus we must do it
2781 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
2782 schedule_on_each_cpu(ftrace_sync);
2784 arch_ftrace_trampoline_free(ops);
2786 if (ops->flags & FTRACE_OPS_FL_PER_CPU)
2787 per_cpu_ops_free(ops);
2793 static void ftrace_startup_sysctl(void)
2797 if (unlikely(ftrace_disabled))
2800 /* Force update next time */
2801 saved_ftrace_func = NULL;
2802 /* ftrace_start_up is true if we want ftrace running */
2803 if (ftrace_start_up) {
2804 command = FTRACE_UPDATE_CALLS;
2805 if (ftrace_graph_active)
2806 command |= FTRACE_START_FUNC_RET;
2807 ftrace_startup_enable(command);
2811 static void ftrace_shutdown_sysctl(void)
2815 if (unlikely(ftrace_disabled))
2818 /* ftrace_start_up is true if ftrace is running */
2819 if (ftrace_start_up) {
2820 command = FTRACE_DISABLE_CALLS;
2821 if (ftrace_graph_active)
2822 command |= FTRACE_STOP_FUNC_RET;
2823 ftrace_run_update_code(command);
2827 static cycle_t ftrace_update_time;
2828 unsigned long ftrace_update_tot_cnt;
2830 static inline int ops_traces_mod(struct ftrace_ops *ops)
2833 * Filter_hash being empty will default to trace module.
2834 * But notrace hash requires a test of individual module functions.
2836 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2837 ftrace_hash_empty(ops->func_hash->notrace_hash);
2841 * Check if the current ops references the record.
2843 * If the ops traces all functions, then it was already accounted for.
2844 * If the ops does not trace the current record function, skip it.
2845 * If the ops ignores the function via notrace filter, skip it.
2848 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2850 /* If ops isn't enabled, ignore it */
2851 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2854 /* If ops traces all then it includes this function */
2855 if (ops_traces_mod(ops))
2858 /* The function must be in the filter */
2859 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2860 !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2863 /* If in notrace hash, we ignore it too */
2864 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2870 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2872 struct ftrace_page *pg;
2873 struct dyn_ftrace *p;
2874 cycle_t start, stop;
2875 unsigned long update_cnt = 0;
2876 unsigned long rec_flags = 0;
2879 start = ftrace_now(raw_smp_processor_id());
2882 * When a module is loaded, this function is called to convert
2883 * the calls to mcount in its text to nops, and also to create
2884 * an entry in the ftrace data. Now, if ftrace is activated
2885 * after this call, but before the module sets its text to
2886 * read-only, the modification of enabling ftrace can fail if
2887 * the read-only is done while ftrace is converting the calls.
2888 * To prevent this, the module's records are set as disabled
2889 * and will be enabled after the call to set the module's text
2893 rec_flags |= FTRACE_FL_DISABLED;
2895 for (pg = new_pgs; pg; pg = pg->next) {
2897 for (i = 0; i < pg->index; i++) {
2899 /* If something went wrong, bail without enabling anything */
2900 if (unlikely(ftrace_disabled))
2903 p = &pg->records[i];
2904 p->flags = rec_flags;
2907 * Do the initial record conversion from mcount jump
2908 * to the NOP instructions.
2910 if (!ftrace_code_disable(mod, p))
2917 stop = ftrace_now(raw_smp_processor_id());
2918 ftrace_update_time = stop - start;
2919 ftrace_update_tot_cnt += update_cnt;
2924 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2929 if (WARN_ON(!count))
2932 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2935 * We want to fill as much as possible. No more than a page
2938 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2942 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2945 /* if we can't allocate this size, try something smaller */
2952 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2961 static struct ftrace_page *
2962 ftrace_allocate_pages(unsigned long num_to_init)
2964 struct ftrace_page *start_pg;
2965 struct ftrace_page *pg;
2972 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2977 * Try to allocate as much as possible in one continues
2978 * location that fills in all of the space. We want to
2979 * waste as little space as possible.
2982 cnt = ftrace_allocate_records(pg, num_to_init);
2990 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3002 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3003 free_pages((unsigned long)pg->records, order);
3004 start_pg = pg->next;
3008 pr_info("ftrace: FAILED to allocate memory for functions\n");
3012 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3014 struct ftrace_iterator {
3017 struct ftrace_page *pg;
3018 struct dyn_ftrace *func;
3019 struct ftrace_func_probe *probe;
3020 struct trace_parser parser;
3021 struct ftrace_hash *hash;
3022 struct ftrace_ops *ops;
3029 t_hash_next(struct seq_file *m, loff_t *pos)
3031 struct ftrace_iterator *iter = m->private;
3032 struct hlist_node *hnd = NULL;
3033 struct hlist_head *hhd;
3039 hnd = &iter->probe->node;
3041 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
3044 hhd = &ftrace_func_hash[iter->hidx];
3046 if (hlist_empty(hhd)) {
3062 if (WARN_ON_ONCE(!hnd))
3065 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
3070 static void *t_hash_start(struct seq_file *m, loff_t *pos)
3072 struct ftrace_iterator *iter = m->private;
3076 if (!(iter->flags & FTRACE_ITER_DO_HASH))
3079 if (iter->func_pos > *pos)
3083 for (l = 0; l <= (*pos - iter->func_pos); ) {
3084 p = t_hash_next(m, &l);
3091 /* Only set this if we have an item */
3092 iter->flags |= FTRACE_ITER_HASH;
3098 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
3100 struct ftrace_func_probe *rec;
3103 if (WARN_ON_ONCE(!rec))
3106 if (rec->ops->print)
3107 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
3109 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
3112 seq_printf(m, ":%p", rec->data);
3119 t_next(struct seq_file *m, void *v, loff_t *pos)
3121 struct ftrace_iterator *iter = m->private;
3122 struct ftrace_ops *ops = iter->ops;
3123 struct dyn_ftrace *rec = NULL;
3125 if (unlikely(ftrace_disabled))
3128 if (iter->flags & FTRACE_ITER_HASH)
3129 return t_hash_next(m, pos);
3132 iter->pos = iter->func_pos = *pos;
3134 if (iter->flags & FTRACE_ITER_PRINTALL)
3135 return t_hash_start(m, pos);
3138 if (iter->idx >= iter->pg->index) {
3139 if (iter->pg->next) {
3140 iter->pg = iter->pg->next;
3145 rec = &iter->pg->records[iter->idx++];
3146 if (((iter->flags & FTRACE_ITER_FILTER) &&
3147 !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
3149 ((iter->flags & FTRACE_ITER_NOTRACE) &&
3150 !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
3152 ((iter->flags & FTRACE_ITER_ENABLED) &&
3153 !(rec->flags & FTRACE_FL_ENABLED))) {
3161 return t_hash_start(m, pos);
3168 static void reset_iter_read(struct ftrace_iterator *iter)
3172 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
3175 static void *t_start(struct seq_file *m, loff_t *pos)
3177 struct ftrace_iterator *iter = m->private;
3178 struct ftrace_ops *ops = iter->ops;
3182 mutex_lock(&ftrace_lock);
3184 if (unlikely(ftrace_disabled))
3188 * If an lseek was done, then reset and start from beginning.
3190 if (*pos < iter->pos)
3191 reset_iter_read(iter);
3194 * For set_ftrace_filter reading, if we have the filter
3195 * off, we can short cut and just print out that all
3196 * functions are enabled.
3198 if ((iter->flags & FTRACE_ITER_FILTER &&
3199 ftrace_hash_empty(ops->func_hash->filter_hash)) ||
3200 (iter->flags & FTRACE_ITER_NOTRACE &&
3201 ftrace_hash_empty(ops->func_hash->notrace_hash))) {
3203 return t_hash_start(m, pos);
3204 iter->flags |= FTRACE_ITER_PRINTALL;
3205 /* reset in case of seek/pread */
3206 iter->flags &= ~FTRACE_ITER_HASH;
3210 if (iter->flags & FTRACE_ITER_HASH)
3211 return t_hash_start(m, pos);
3214 * Unfortunately, we need to restart at ftrace_pages_start
3215 * every time we let go of the ftrace_mutex. This is because
3216 * those pointers can change without the lock.
3218 iter->pg = ftrace_pages_start;
3220 for (l = 0; l <= *pos; ) {
3221 p = t_next(m, p, &l);
3227 return t_hash_start(m, pos);
3232 static void t_stop(struct seq_file *m, void *p)
3234 mutex_unlock(&ftrace_lock);
3238 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3243 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3244 struct dyn_ftrace *rec)
3248 ptr = arch_ftrace_trampoline_func(ops, rec);
3250 seq_printf(m, " ->%pS", ptr);
3253 static int t_show(struct seq_file *m, void *v)
3255 struct ftrace_iterator *iter = m->private;
3256 struct dyn_ftrace *rec;
3258 if (iter->flags & FTRACE_ITER_HASH)
3259 return t_hash_show(m, iter);
3261 if (iter->flags & FTRACE_ITER_PRINTALL) {
3262 if (iter->flags & FTRACE_ITER_NOTRACE)
3263 seq_puts(m, "#### no functions disabled ####\n");
3265 seq_puts(m, "#### all functions enabled ####\n");
3274 seq_printf(m, "%ps", (void *)rec->ip);
3275 if (iter->flags & FTRACE_ITER_ENABLED) {
3276 struct ftrace_ops *ops;
3278 seq_printf(m, " (%ld)%s%s",
3279 ftrace_rec_count(rec),
3280 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3281 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
3282 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3283 ops = ftrace_find_tramp_ops_any(rec);
3286 seq_printf(m, "\ttramp: %pS (%pS)",
3287 (void *)ops->trampoline,
3289 add_trampoline_func(m, ops, rec);
3290 ops = ftrace_find_tramp_ops_next(rec, ops);
3293 seq_puts(m, "\ttramp: ERROR!");
3295 add_trampoline_func(m, NULL, rec);
3304 static const struct seq_operations show_ftrace_seq_ops = {
3312 ftrace_avail_open(struct inode *inode, struct file *file)
3314 struct ftrace_iterator *iter;
3316 if (unlikely(ftrace_disabled))
3319 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3321 iter->pg = ftrace_pages_start;
3322 iter->ops = &global_ops;
3325 return iter ? 0 : -ENOMEM;
3329 ftrace_enabled_open(struct inode *inode, struct file *file)
3331 struct ftrace_iterator *iter;
3333 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3335 iter->pg = ftrace_pages_start;
3336 iter->flags = FTRACE_ITER_ENABLED;
3337 iter->ops = &global_ops;
3340 return iter ? 0 : -ENOMEM;
3344 * ftrace_regex_open - initialize function tracer filter files
3345 * @ops: The ftrace_ops that hold the hash filters
3346 * @flag: The type of filter to process
3347 * @inode: The inode, usually passed in to your open routine
3348 * @file: The file, usually passed in to your open routine
3350 * ftrace_regex_open() initializes the filter files for the
3351 * @ops. Depending on @flag it may process the filter hash or
3352 * the notrace hash of @ops. With this called from the open
3353 * routine, you can use ftrace_filter_write() for the write
3354 * routine if @flag has FTRACE_ITER_FILTER set, or
3355 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3356 * tracing_lseek() should be used as the lseek routine, and
3357 * release must call ftrace_regex_release().
3360 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3361 struct inode *inode, struct file *file)
3363 struct ftrace_iterator *iter;
3364 struct ftrace_hash *hash;
3367 ftrace_ops_init(ops);
3369 if (unlikely(ftrace_disabled))
3372 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3376 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3384 mutex_lock(&ops->func_hash->regex_lock);
3386 if (flag & FTRACE_ITER_NOTRACE)
3387 hash = ops->func_hash->notrace_hash;
3389 hash = ops->func_hash->filter_hash;
3391 if (file->f_mode & FMODE_WRITE) {
3392 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3394 if (file->f_flags & O_TRUNC)
3395 iter->hash = alloc_ftrace_hash(size_bits);
3397 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3400 trace_parser_put(&iter->parser);
3407 if (file->f_mode & FMODE_READ) {
3408 iter->pg = ftrace_pages_start;
3410 ret = seq_open(file, &show_ftrace_seq_ops);
3412 struct seq_file *m = file->private_data;
3416 free_ftrace_hash(iter->hash);
3417 trace_parser_put(&iter->parser);
3421 file->private_data = iter;
3424 mutex_unlock(&ops->func_hash->regex_lock);
3430 ftrace_filter_open(struct inode *inode, struct file *file)
3432 struct ftrace_ops *ops = inode->i_private;
3434 return ftrace_regex_open(ops,
3435 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3440 ftrace_notrace_open(struct inode *inode, struct file *file)
3442 struct ftrace_ops *ops = inode->i_private;
3444 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3448 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3449 struct ftrace_glob {
3455 static int ftrace_match(char *str, struct ftrace_glob *g)
3462 if (strcmp(str, g->search) == 0)
3465 case MATCH_FRONT_ONLY:
3466 if (strncmp(str, g->search, g->len) == 0)
3469 case MATCH_MIDDLE_ONLY:
3470 if (strstr(str, g->search))
3473 case MATCH_END_ONLY:
3475 if (slen >= g->len &&
3476 memcmp(str + slen - g->len, g->search, g->len) == 0)
3485 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3487 struct ftrace_func_entry *entry;
3490 entry = ftrace_lookup_ip(hash, rec->ip);
3492 /* Do nothing if it doesn't exist */
3496 free_hash_entry(hash, entry);
3498 /* Do nothing if it exists */
3502 ret = add_hash_entry(hash, rec->ip);
3508 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3509 struct ftrace_glob *mod_g, int exclude_mod)
3511 char str[KSYM_SYMBOL_LEN];
3514 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3517 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3519 /* blank module name to match all modules */
3521 /* blank module globbing: modname xor exclude_mod */
3522 if ((!exclude_mod) != (!modname))
3527 /* not matching the module */
3528 if (!modname || !mod_matches) {
3535 if (mod_matches && exclude_mod)
3539 /* blank search means to match all funcs in the mod */
3544 return ftrace_match(str, func_g);
3548 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3550 struct ftrace_page *pg;
3551 struct dyn_ftrace *rec;
3552 struct ftrace_glob func_g = { .type = MATCH_FULL };
3553 struct ftrace_glob mod_g = { .type = MATCH_FULL };
3554 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3555 int exclude_mod = 0;
3561 func_g.type = filter_parse_regex(func, len, &func_g.search,
3563 func_g.len = strlen(func_g.search);
3567 mod_g.type = filter_parse_regex(mod, strlen(mod),
3568 &mod_g.search, &exclude_mod);
3569 mod_g.len = strlen(mod_g.search);
3572 mutex_lock(&ftrace_lock);
3574 if (unlikely(ftrace_disabled))
3577 do_for_each_ftrace_rec(pg, rec) {
3578 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3579 ret = enter_record(hash, rec, clear_filter);
3586 } while_for_each_ftrace_rec();
3588 mutex_unlock(&ftrace_lock);
3594 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3596 return match_records(hash, buff, len, NULL);
3601 * We register the module command as a template to show others how
3602 * to register the a command as well.
3606 ftrace_mod_callback(struct ftrace_hash *hash,
3607 char *func, char *cmd, char *module, int enable)
3612 * cmd == 'mod' because we only registered this func
3613 * for the 'mod' ftrace_func_command.
3614 * But if you register one func with multiple commands,
3615 * you can tell which command was used by the cmd
3618 ret = match_records(hash, func, strlen(func), module);
3626 static struct ftrace_func_command ftrace_mod_cmd = {
3628 .func = ftrace_mod_callback,
3631 static int __init ftrace_mod_cmd_init(void)
3633 return register_ftrace_command(&ftrace_mod_cmd);
3635 core_initcall(ftrace_mod_cmd_init);
3637 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3638 struct ftrace_ops *op, struct pt_regs *pt_regs)
3640 struct ftrace_func_probe *entry;
3641 struct hlist_head *hhd;
3644 key = hash_long(ip, FTRACE_HASH_BITS);
3646 hhd = &ftrace_func_hash[key];
3648 if (hlist_empty(hhd))
3652 * Disable preemption for these calls to prevent a RCU grace
3653 * period. This syncs the hash iteration and freeing of items
3654 * on the hash. rcu_read_lock is too dangerous here.
3656 preempt_disable_notrace();
3657 hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3658 if (entry->ip == ip)
3659 entry->ops->func(ip, parent_ip, &entry->data);
3661 preempt_enable_notrace();
3664 static struct ftrace_ops trace_probe_ops __read_mostly =
3666 .func = function_trace_probe_call,
3667 .flags = FTRACE_OPS_FL_INITIALIZED,
3668 INIT_OPS_HASH(trace_probe_ops)
3671 static int ftrace_probe_registered;
3673 static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3678 if (ftrace_probe_registered) {
3679 /* still need to update the function call sites */
3681 ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3686 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3687 struct hlist_head *hhd = &ftrace_func_hash[i];
3691 /* Nothing registered? */
3692 if (i == FTRACE_FUNC_HASHSIZE)
3695 ret = ftrace_startup(&trace_probe_ops, 0);
3697 ftrace_probe_registered = 1;
3700 static void __disable_ftrace_function_probe(void)
3704 if (!ftrace_probe_registered)
3707 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3708 struct hlist_head *hhd = &ftrace_func_hash[i];
3713 /* no more funcs left */
3714 ftrace_shutdown(&trace_probe_ops, 0);
3716 ftrace_probe_registered = 0;
3720 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3722 if (entry->ops->free)
3723 entry->ops->free(entry->ops, entry->ip, &entry->data);
3728 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3731 struct ftrace_ops_hash old_hash_ops;
3732 struct ftrace_func_probe *entry;
3733 struct ftrace_glob func_g;
3734 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3735 struct ftrace_hash *old_hash = *orig_hash;
3736 struct ftrace_hash *hash;
3737 struct ftrace_page *pg;
3738 struct dyn_ftrace *rec;
3744 func_g.type = filter_parse_regex(glob, strlen(glob),
3745 &func_g.search, ¬);
3746 func_g.len = strlen(func_g.search);
3748 /* we do not support '!' for function probes */
3752 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3754 old_hash_ops.filter_hash = old_hash;
3755 /* Probes only have filters */
3756 old_hash_ops.notrace_hash = NULL;
3758 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3764 if (unlikely(ftrace_disabled)) {
3769 mutex_lock(&ftrace_lock);
3771 do_for_each_ftrace_rec(pg, rec) {
3773 if (!ftrace_match_record(rec, &func_g, NULL, 0))
3776 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3778 /* If we did not process any, then return error */
3789 * The caller might want to do something special
3790 * for each function we find. We call the callback
3791 * to give the caller an opportunity to do so.
3794 if (ops->init(ops, rec->ip, &entry->data) < 0) {
3795 /* caller does not like this func */
3801 ret = enter_record(hash, rec, 0);
3809 entry->ip = rec->ip;
3811 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3812 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3814 } while_for_each_ftrace_rec();
3816 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3818 __enable_ftrace_function_probe(&old_hash_ops);
3821 free_ftrace_hash_rcu(old_hash);
3826 mutex_unlock(&ftrace_lock);
3828 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3829 free_ftrace_hash(hash);
3835 PROBE_TEST_FUNC = 1,
3840 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3841 void *data, int flags)
3843 struct ftrace_func_entry *rec_entry;
3844 struct ftrace_func_probe *entry;
3845 struct ftrace_func_probe *p;
3846 struct ftrace_glob func_g;
3847 struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3848 struct ftrace_hash *old_hash = *orig_hash;
3849 struct list_head free_list;
3850 struct ftrace_hash *hash;
3851 struct hlist_node *tmp;
3852 char str[KSYM_SYMBOL_LEN];
3855 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3856 func_g.search = NULL;
3860 func_g.type = filter_parse_regex(glob, strlen(glob),
3861 &func_g.search, ¬);
3862 func_g.len = strlen(func_g.search);
3863 func_g.search = glob;
3865 /* we do not support '!' for function probes */
3870 mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3872 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3874 /* Hmm, should report this somehow */
3877 INIT_LIST_HEAD(&free_list);
3879 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3880 struct hlist_head *hhd = &ftrace_func_hash[i];
3882 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3884 /* break up if statements for readability */
3885 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3888 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3891 /* do this last, since it is the most expensive */
3892 if (func_g.search) {
3893 kallsyms_lookup(entry->ip, NULL, NULL,
3895 if (!ftrace_match(str, &func_g))
3899 rec_entry = ftrace_lookup_ip(hash, entry->ip);
3900 /* It is possible more than one entry had this ip */
3902 free_hash_entry(hash, rec_entry);
3904 hlist_del_rcu(&entry->node);
3905 list_add(&entry->free_list, &free_list);
3908 mutex_lock(&ftrace_lock);
3909 __disable_ftrace_function_probe();
3911 * Remove after the disable is called. Otherwise, if the last
3912 * probe is removed, a null hash means *all enabled*.
3914 ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3915 synchronize_sched();
3917 free_ftrace_hash_rcu(old_hash);
3919 list_for_each_entry_safe(entry, p, &free_list, free_list) {
3920 list_del(&entry->free_list);
3921 ftrace_free_entry(entry);
3923 mutex_unlock(&ftrace_lock);
3926 mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3927 free_ftrace_hash(hash);
3931 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3934 __unregister_ftrace_function_probe(glob, ops, data,
3935 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3939 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3941 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3944 void unregister_ftrace_function_probe_all(char *glob)
3946 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3949 static LIST_HEAD(ftrace_commands);
3950 static DEFINE_MUTEX(ftrace_cmd_mutex);
3953 * Currently we only register ftrace commands from __init, so mark this
3956 __init int register_ftrace_command(struct ftrace_func_command *cmd)
3958 struct ftrace_func_command *p;
3961 mutex_lock(&ftrace_cmd_mutex);
3962 list_for_each_entry(p, &ftrace_commands, list) {
3963 if (strcmp(cmd->name, p->name) == 0) {
3968 list_add(&cmd->list, &ftrace_commands);
3970 mutex_unlock(&ftrace_cmd_mutex);
3976 * Currently we only unregister ftrace commands from __init, so mark
3979 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3981 struct ftrace_func_command *p, *n;
3984 mutex_lock(&ftrace_cmd_mutex);
3985 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3986 if (strcmp(cmd->name, p->name) == 0) {
3988 list_del_init(&p->list);
3993 mutex_unlock(&ftrace_cmd_mutex);
3998 static int ftrace_process_regex(struct ftrace_hash *hash,
3999 char *buff, int len, int enable)
4001 char *func, *command, *next = buff;
4002 struct ftrace_func_command *p;
4005 func = strsep(&next, ":");
4008 ret = ftrace_match_records(hash, func, len);
4018 command = strsep(&next, ":");
4020 mutex_lock(&ftrace_cmd_mutex);
4021 list_for_each_entry(p, &ftrace_commands, list) {
4022 if (strcmp(p->name, command) == 0) {
4023 ret = p->func(hash, func, command, next, enable);
4028 mutex_unlock(&ftrace_cmd_mutex);
4034 ftrace_regex_write(struct file *file, const char __user *ubuf,
4035 size_t cnt, loff_t *ppos, int enable)
4037 struct ftrace_iterator *iter;
4038 struct trace_parser *parser;
4044 if (file->f_mode & FMODE_READ) {
4045 struct seq_file *m = file->private_data;
4048 iter = file->private_data;
4050 if (unlikely(ftrace_disabled))
4053 /* iter->hash is a local copy, so we don't need regex_lock */
4055 parser = &iter->parser;
4056 read = trace_get_user(parser, ubuf, cnt, ppos);
4058 if (read >= 0 && trace_parser_loaded(parser) &&
4059 !trace_parser_cont(parser)) {
4060 ret = ftrace_process_regex(iter->hash, parser->buffer,
4061 parser->idx, enable);
4062 trace_parser_clear(parser);
4073 ftrace_filter_write(struct file *file, const char __user *ubuf,
4074 size_t cnt, loff_t *ppos)
4076 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4080 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4081 size_t cnt, loff_t *ppos)
4083 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4087 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4089 struct ftrace_func_entry *entry;
4091 if (!ftrace_location(ip))
4095 entry = ftrace_lookup_ip(hash, ip);
4098 free_hash_entry(hash, entry);
4102 return add_hash_entry(hash, ip);
4105 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4106 struct ftrace_ops_hash *old_hash)
4108 struct ftrace_ops *op;
4110 if (!ftrace_enabled)
4113 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4114 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4119 * If this is the shared global_ops filter, then we need to
4120 * check if there is another ops that shares it, is enabled.
4121 * If so, we still need to run the modify code.
4123 if (ops->func_hash != &global_ops.local_hash)
4126 do_for_each_ftrace_op(op, ftrace_ops_list) {
4127 if (op->func_hash == &global_ops.local_hash &&
4128 op->flags & FTRACE_OPS_FL_ENABLED) {
4129 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4130 /* Only need to do this once */
4133 } while_for_each_ftrace_op(op);
4137 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4138 unsigned long ip, int remove, int reset, int enable)
4140 struct ftrace_hash **orig_hash;
4141 struct ftrace_ops_hash old_hash_ops;
4142 struct ftrace_hash *old_hash;
4143 struct ftrace_hash *hash;
4146 if (unlikely(ftrace_disabled))
4149 mutex_lock(&ops->func_hash->regex_lock);
4152 orig_hash = &ops->func_hash->filter_hash;
4154 orig_hash = &ops->func_hash->notrace_hash;
4157 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4159 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4163 goto out_regex_unlock;
4166 if (buf && !ftrace_match_records(hash, buf, len)) {
4168 goto out_regex_unlock;
4171 ret = ftrace_match_addr(hash, ip, remove);
4173 goto out_regex_unlock;
4176 mutex_lock(&ftrace_lock);
4177 old_hash = *orig_hash;
4178 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4179 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4180 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4182 ftrace_ops_update_code(ops, &old_hash_ops);
4183 free_ftrace_hash_rcu(old_hash);
4185 mutex_unlock(&ftrace_lock);
4188 mutex_unlock(&ops->func_hash->regex_lock);
4190 free_ftrace_hash(hash);
4195 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4196 int reset, int enable)
4198 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4202 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4203 * @ops - the ops to set the filter with
4204 * @ip - the address to add to or remove from the filter.
4205 * @remove - non zero to remove the ip from the filter
4206 * @reset - non zero to reset all filters before applying this filter.
4208 * Filters denote which functions should be enabled when tracing is enabled
4209 * If @ip is NULL, it failes to update filter.
4211 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4212 int remove, int reset)
4214 ftrace_ops_init(ops);
4215 return ftrace_set_addr(ops, ip, remove, reset, 1);
4217 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4220 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4221 int reset, int enable)
4223 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4227 * ftrace_set_filter - set a function to filter on in ftrace
4228 * @ops - the ops to set the filter with
4229 * @buf - the string that holds the function filter text.
4230 * @len - the length of the string.
4231 * @reset - non zero to reset all filters before applying this filter.
4233 * Filters denote which functions should be enabled when tracing is enabled.
4234 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4236 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4239 ftrace_ops_init(ops);
4240 return ftrace_set_regex(ops, buf, len, reset, 1);
4242 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4245 * ftrace_set_notrace - set a function to not trace in ftrace
4246 * @ops - the ops to set the notrace filter with
4247 * @buf - the string that holds the function notrace text.
4248 * @len - the length of the string.
4249 * @reset - non zero to reset all filters before applying this filter.
4251 * Notrace Filters denote which functions should not be enabled when tracing
4252 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4255 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4258 ftrace_ops_init(ops);
4259 return ftrace_set_regex(ops, buf, len, reset, 0);
4261 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4263 * ftrace_set_global_filter - set a function to filter on with global tracers
4264 * @buf - the string that holds the function filter text.
4265 * @len - the length of the string.
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 @buf is NULL and reset is set, all functions will be enabled for tracing.
4271 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4273 ftrace_set_regex(&global_ops, buf, len, reset, 1);
4275 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4278 * ftrace_set_global_notrace - set a function to not trace with global tracers
4279 * @buf - the string that holds the function notrace text.
4280 * @len - the length of the string.
4281 * @reset - non zero to reset all filters before applying this filter.
4283 * Notrace Filters denote which functions should not be enabled when tracing
4284 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4287 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4289 ftrace_set_regex(&global_ops, buf, len, reset, 0);
4291 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4294 * command line interface to allow users to set filters on boot up.
4296 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
4297 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4298 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4300 /* Used by function selftest to not test if filter is set */
4301 bool ftrace_filter_param __initdata;
4303 static int __init set_ftrace_notrace(char *str)
4305 ftrace_filter_param = true;
4306 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4309 __setup("ftrace_notrace=", set_ftrace_notrace);
4311 static int __init set_ftrace_filter(char *str)
4313 ftrace_filter_param = true;
4314 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4317 __setup("ftrace_filter=", set_ftrace_filter);
4319 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4320 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4321 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4322 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4324 static unsigned long save_global_trampoline;
4325 static unsigned long save_global_flags;
4327 static int __init set_graph_function(char *str)
4329 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4332 __setup("ftrace_graph_filter=", set_graph_function);
4334 static int __init set_graph_notrace_function(char *str)
4336 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4339 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4341 static void __init set_ftrace_early_graph(char *buf, int enable)
4345 unsigned long *table = ftrace_graph_funcs;
4346 int *count = &ftrace_graph_count;
4349 table = ftrace_graph_notrace_funcs;
4350 count = &ftrace_graph_notrace_count;
4354 func = strsep(&buf, ",");
4355 /* we allow only one expression at a time */
4356 ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4358 printk(KERN_DEBUG "ftrace: function %s not "
4359 "traceable\n", func);
4362 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4365 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4369 ftrace_ops_init(ops);
4372 func = strsep(&buf, ",");
4373 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4377 static void __init set_ftrace_early_filters(void)
4379 if (ftrace_filter_buf[0])
4380 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4381 if (ftrace_notrace_buf[0])
4382 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4383 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4384 if (ftrace_graph_buf[0])
4385 set_ftrace_early_graph(ftrace_graph_buf, 1);
4386 if (ftrace_graph_notrace_buf[0])
4387 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4388 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4391 int ftrace_regex_release(struct inode *inode, struct file *file)
4393 struct seq_file *m = (struct seq_file *)file->private_data;
4394 struct ftrace_ops_hash old_hash_ops;
4395 struct ftrace_iterator *iter;
4396 struct ftrace_hash **orig_hash;
4397 struct ftrace_hash *old_hash;
4398 struct trace_parser *parser;
4402 if (file->f_mode & FMODE_READ) {
4404 seq_release(inode, file);
4406 iter = file->private_data;
4408 parser = &iter->parser;
4409 if (trace_parser_loaded(parser)) {
4410 parser->buffer[parser->idx] = 0;
4411 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4414 trace_parser_put(parser);
4416 mutex_lock(&iter->ops->func_hash->regex_lock);
4418 if (file->f_mode & FMODE_WRITE) {
4419 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4422 orig_hash = &iter->ops->func_hash->filter_hash;
4424 orig_hash = &iter->ops->func_hash->notrace_hash;
4426 mutex_lock(&ftrace_lock);
4427 old_hash = *orig_hash;
4428 old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4429 old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4430 ret = ftrace_hash_move(iter->ops, filter_hash,
4431 orig_hash, iter->hash);
4433 ftrace_ops_update_code(iter->ops, &old_hash_ops);
4434 free_ftrace_hash_rcu(old_hash);
4436 mutex_unlock(&ftrace_lock);
4439 mutex_unlock(&iter->ops->func_hash->regex_lock);
4440 free_ftrace_hash(iter->hash);
4446 static const struct file_operations ftrace_avail_fops = {
4447 .open = ftrace_avail_open,
4449 .llseek = seq_lseek,
4450 .release = seq_release_private,
4453 static const struct file_operations ftrace_enabled_fops = {
4454 .open = ftrace_enabled_open,
4456 .llseek = seq_lseek,
4457 .release = seq_release_private,
4460 static const struct file_operations ftrace_filter_fops = {
4461 .open = ftrace_filter_open,
4463 .write = ftrace_filter_write,
4464 .llseek = tracing_lseek,
4465 .release = ftrace_regex_release,
4468 static const struct file_operations ftrace_notrace_fops = {
4469 .open = ftrace_notrace_open,
4471 .write = ftrace_notrace_write,
4472 .llseek = tracing_lseek,
4473 .release = ftrace_regex_release,
4476 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4478 static DEFINE_MUTEX(graph_lock);
4480 int ftrace_graph_count;
4481 int ftrace_graph_notrace_count;
4482 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4483 unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4485 struct ftrace_graph_data {
4486 unsigned long *table;
4489 const struct seq_operations *seq_ops;
4493 __g_next(struct seq_file *m, loff_t *pos)
4495 struct ftrace_graph_data *fgd = m->private;
4497 if (*pos >= *fgd->count)
4499 return &fgd->table[*pos];
4503 g_next(struct seq_file *m, void *v, loff_t *pos)
4506 return __g_next(m, pos);
4509 static void *g_start(struct seq_file *m, loff_t *pos)
4511 struct ftrace_graph_data *fgd = m->private;
4513 mutex_lock(&graph_lock);
4515 /* Nothing, tell g_show to print all functions are enabled */
4516 if (!*fgd->count && !*pos)
4519 return __g_next(m, pos);
4522 static void g_stop(struct seq_file *m, void *p)
4524 mutex_unlock(&graph_lock);
4527 static int g_show(struct seq_file *m, void *v)
4529 unsigned long *ptr = v;
4534 if (ptr == (unsigned long *)1) {
4535 struct ftrace_graph_data *fgd = m->private;
4537 if (fgd->table == ftrace_graph_funcs)
4538 seq_puts(m, "#### all functions enabled ####\n");
4540 seq_puts(m, "#### no functions disabled ####\n");
4544 seq_printf(m, "%ps\n", (void *)*ptr);
4549 static const struct seq_operations ftrace_graph_seq_ops = {
4557 __ftrace_graph_open(struct inode *inode, struct file *file,
4558 struct ftrace_graph_data *fgd)
4562 mutex_lock(&graph_lock);
4563 if ((file->f_mode & FMODE_WRITE) &&
4564 (file->f_flags & O_TRUNC)) {
4566 memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4568 mutex_unlock(&graph_lock);
4570 if (file->f_mode & FMODE_READ) {
4571 ret = seq_open(file, fgd->seq_ops);
4573 struct seq_file *m = file->private_data;
4577 file->private_data = fgd;
4583 ftrace_graph_open(struct inode *inode, struct file *file)
4585 struct ftrace_graph_data *fgd;
4587 if (unlikely(ftrace_disabled))
4590 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4594 fgd->table = ftrace_graph_funcs;
4595 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4596 fgd->count = &ftrace_graph_count;
4597 fgd->seq_ops = &ftrace_graph_seq_ops;
4599 return __ftrace_graph_open(inode, file, fgd);
4603 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4605 struct ftrace_graph_data *fgd;
4607 if (unlikely(ftrace_disabled))
4610 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4614 fgd->table = ftrace_graph_notrace_funcs;
4615 fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4616 fgd->count = &ftrace_graph_notrace_count;
4617 fgd->seq_ops = &ftrace_graph_seq_ops;
4619 return __ftrace_graph_open(inode, file, fgd);
4623 ftrace_graph_release(struct inode *inode, struct file *file)
4625 if (file->f_mode & FMODE_READ) {
4626 struct seq_file *m = file->private_data;
4629 seq_release(inode, file);
4631 kfree(file->private_data);
4638 ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4640 struct ftrace_glob func_g;
4641 struct dyn_ftrace *rec;
4642 struct ftrace_page *pg;
4649 func_g.type = filter_parse_regex(buffer, strlen(buffer),
4650 &func_g.search, ¬);
4651 if (!not && *idx >= size)
4654 func_g.len = strlen(func_g.search);
4656 mutex_lock(&ftrace_lock);
4658 if (unlikely(ftrace_disabled)) {
4659 mutex_unlock(&ftrace_lock);
4663 do_for_each_ftrace_rec(pg, rec) {
4665 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
4666 /* if it is in the array */
4668 for (i = 0; i < *idx; i++) {
4669 if (array[i] == rec->ip) {
4678 array[(*idx)++] = rec->ip;
4684 array[i] = array[--(*idx)];
4690 } while_for_each_ftrace_rec();
4692 mutex_unlock(&ftrace_lock);
4701 ftrace_graph_write(struct file *file, const char __user *ubuf,
4702 size_t cnt, loff_t *ppos)
4704 struct trace_parser parser;
4705 ssize_t read, ret = 0;
4706 struct ftrace_graph_data *fgd = file->private_data;
4711 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4714 read = trace_get_user(&parser, ubuf, cnt, ppos);
4716 if (read >= 0 && trace_parser_loaded((&parser))) {
4717 parser.buffer[parser.idx] = 0;
4719 mutex_lock(&graph_lock);
4721 /* we allow only one expression at a time */
4722 ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4725 mutex_unlock(&graph_lock);
4731 trace_parser_put(&parser);
4736 static const struct file_operations ftrace_graph_fops = {
4737 .open = ftrace_graph_open,
4739 .write = ftrace_graph_write,
4740 .llseek = tracing_lseek,
4741 .release = ftrace_graph_release,
4744 static const struct file_operations ftrace_graph_notrace_fops = {
4745 .open = ftrace_graph_notrace_open,
4747 .write = ftrace_graph_write,
4748 .llseek = tracing_lseek,
4749 .release = ftrace_graph_release,
4751 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4753 void ftrace_create_filter_files(struct ftrace_ops *ops,
4754 struct dentry *parent)
4757 trace_create_file("set_ftrace_filter", 0644, parent,
4758 ops, &ftrace_filter_fops);
4760 trace_create_file("set_ftrace_notrace", 0644, parent,
4761 ops, &ftrace_notrace_fops);
4765 * The name "destroy_filter_files" is really a misnomer. Although
4766 * in the future, it may actualy delete the files, but this is
4767 * really intended to make sure the ops passed in are disabled
4768 * and that when this function returns, the caller is free to
4771 * The "destroy" name is only to match the "create" name that this
4772 * should be paired with.
4774 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4776 mutex_lock(&ftrace_lock);
4777 if (ops->flags & FTRACE_OPS_FL_ENABLED)
4778 ftrace_shutdown(ops, 0);
4779 ops->flags |= FTRACE_OPS_FL_DELETED;
4780 mutex_unlock(&ftrace_lock);
4783 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
4786 trace_create_file("available_filter_functions", 0444,
4787 d_tracer, NULL, &ftrace_avail_fops);
4789 trace_create_file("enabled_functions", 0444,
4790 d_tracer, NULL, &ftrace_enabled_fops);
4792 ftrace_create_filter_files(&global_ops, d_tracer);
4794 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4795 trace_create_file("set_graph_function", 0444, d_tracer,
4797 &ftrace_graph_fops);
4798 trace_create_file("set_graph_notrace", 0444, d_tracer,
4800 &ftrace_graph_notrace_fops);
4801 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4806 static int ftrace_cmp_ips(const void *a, const void *b)
4808 const unsigned long *ipa = a;
4809 const unsigned long *ipb = b;
4818 static int ftrace_process_locs(struct module *mod,
4819 unsigned long *start,
4822 struct ftrace_page *start_pg;
4823 struct ftrace_page *pg;
4824 struct dyn_ftrace *rec;
4825 unsigned long count;
4828 unsigned long flags = 0; /* Shut up gcc */
4831 count = end - start;
4836 sort(start, count, sizeof(*start),
4837 ftrace_cmp_ips, NULL);
4839 start_pg = ftrace_allocate_pages(count);
4843 mutex_lock(&ftrace_lock);
4846 * Core and each module needs their own pages, as
4847 * modules will free them when they are removed.
4848 * Force a new page to be allocated for modules.
4851 WARN_ON(ftrace_pages || ftrace_pages_start);
4852 /* First initialization */
4853 ftrace_pages = ftrace_pages_start = start_pg;
4858 if (WARN_ON(ftrace_pages->next)) {
4859 /* Hmm, we have free pages? */
4860 while (ftrace_pages->next)
4861 ftrace_pages = ftrace_pages->next;
4864 ftrace_pages->next = start_pg;
4870 addr = ftrace_call_adjust(*p++);
4872 * Some architecture linkers will pad between
4873 * the different mcount_loc sections of different
4874 * object files to satisfy alignments.
4875 * Skip any NULL pointers.
4880 if (pg->index == pg->size) {
4881 /* We should have allocated enough */
4882 if (WARN_ON(!pg->next))
4887 rec = &pg->records[pg->index++];
4891 /* We should have used all pages */
4894 /* Assign the last page to ftrace_pages */
4898 * We only need to disable interrupts on start up
4899 * because we are modifying code that an interrupt
4900 * may execute, and the modification is not atomic.
4901 * But for modules, nothing runs the code we modify
4902 * until we are finished with it, and there's no
4903 * reason to cause large interrupt latencies while we do it.
4906 local_irq_save(flags);
4907 ftrace_update_code(mod, start_pg);
4909 local_irq_restore(flags);
4912 mutex_unlock(&ftrace_lock);
4917 #ifdef CONFIG_MODULES
4919 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4921 static int referenced_filters(struct dyn_ftrace *rec)
4923 struct ftrace_ops *ops;
4926 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
4927 if (ops_references_rec(ops, rec))
4934 void ftrace_release_mod(struct module *mod)
4936 struct dyn_ftrace *rec;
4937 struct ftrace_page **last_pg;
4938 struct ftrace_page *pg;
4941 mutex_lock(&ftrace_lock);
4943 if (ftrace_disabled)
4947 * Each module has its own ftrace_pages, remove
4948 * them from the list.
4950 last_pg = &ftrace_pages_start;
4951 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4952 rec = &pg->records[0];
4953 if (within_module_core(rec->ip, mod)) {
4955 * As core pages are first, the first
4956 * page should never be a module page.
4958 if (WARN_ON(pg == ftrace_pages_start))
4961 /* Check if we are deleting the last page */
4962 if (pg == ftrace_pages)
4963 ftrace_pages = next_to_ftrace_page(last_pg);
4965 *last_pg = pg->next;
4966 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4967 free_pages((unsigned long)pg->records, order);
4970 last_pg = &pg->next;
4973 mutex_unlock(&ftrace_lock);
4976 void ftrace_module_enable(struct module *mod)
4978 struct dyn_ftrace *rec;
4979 struct ftrace_page *pg;
4981 mutex_lock(&ftrace_lock);
4983 if (ftrace_disabled)
4987 * If the tracing is enabled, go ahead and enable the record.
4989 * The reason not to enable the record immediatelly is the
4990 * inherent check of ftrace_make_nop/ftrace_make_call for
4991 * correct previous instructions. Making first the NOP
4992 * conversion puts the module to the correct state, thus
4993 * passing the ftrace_make_call check.
4995 * We also delay this to after the module code already set the
4996 * text to read-only, as we now need to set it back to read-write
4997 * so that we can modify the text.
4999 if (ftrace_start_up)
5000 ftrace_arch_code_modify_prepare();
5002 do_for_each_ftrace_rec(pg, rec) {
5005 * do_for_each_ftrace_rec() is a double loop.
5006 * module text shares the pg. If a record is
5007 * not part of this module, then skip this pg,
5008 * which the "break" will do.
5010 if (!within_module_core(rec->ip, mod))
5016 * When adding a module, we need to check if tracers are
5017 * currently enabled and if they are, and can trace this record,
5018 * we need to enable the module functions as well as update the
5019 * reference counts for those function records.
5021 if (ftrace_start_up)
5022 cnt += referenced_filters(rec);
5024 /* This clears FTRACE_FL_DISABLED */
5027 if (ftrace_start_up && cnt) {
5028 int failed = __ftrace_replace_code(rec, 1);
5030 ftrace_bug(failed, rec);
5035 } while_for_each_ftrace_rec();
5038 if (ftrace_start_up)
5039 ftrace_arch_code_modify_post_process();
5042 mutex_unlock(&ftrace_lock);
5045 void ftrace_module_init(struct module *mod)
5047 if (ftrace_disabled || !mod->num_ftrace_callsites)
5050 ftrace_process_locs(mod, mod->ftrace_callsites,
5051 mod->ftrace_callsites + mod->num_ftrace_callsites);
5053 #endif /* CONFIG_MODULES */
5055 void __init ftrace_init(void)
5057 extern unsigned long __start_mcount_loc[];
5058 extern unsigned long __stop_mcount_loc[];
5059 unsigned long count, flags;
5062 local_irq_save(flags);
5063 ret = ftrace_dyn_arch_init();
5064 local_irq_restore(flags);
5068 count = __stop_mcount_loc - __start_mcount_loc;
5070 pr_info("ftrace: No functions to be traced?\n");
5074 pr_info("ftrace: allocating %ld entries in %ld pages\n",
5075 count, count / ENTRIES_PER_PAGE + 1);
5077 last_ftrace_enabled = ftrace_enabled = 1;
5079 ret = ftrace_process_locs(NULL,
5083 set_ftrace_early_filters();
5087 ftrace_disabled = 1;
5090 /* Do nothing if arch does not support this */
5091 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
5095 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5099 * Currently there's no safe way to free a trampoline when the kernel
5100 * is configured with PREEMPT. That is because a task could be preempted
5101 * when it jumped to the trampoline, it may be preempted for a long time
5102 * depending on the system load, and currently there's no way to know
5103 * when it will be off the trampoline. If the trampoline is freed
5104 * too early, when the task runs again, it will be executing on freed
5107 #ifdef CONFIG_PREEMPT
5108 /* Currently, only non dynamic ops can have a trampoline */
5109 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
5113 arch_ftrace_update_trampoline(ops);
5118 static struct ftrace_ops global_ops = {
5119 .func = ftrace_stub,
5120 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5121 FTRACE_OPS_FL_INITIALIZED |
5125 static int __init ftrace_nodyn_init(void)
5130 core_initcall(ftrace_nodyn_init);
5132 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
5133 static inline void ftrace_startup_enable(int command) { }
5134 static inline void ftrace_startup_all(int command) { }
5135 /* Keep as macros so we do not need to define the commands */
5136 # define ftrace_startup(ops, command) \
5138 int ___ret = __register_ftrace_function(ops); \
5140 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
5143 # define ftrace_shutdown(ops, command) \
5145 int ___ret = __unregister_ftrace_function(ops); \
5147 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \
5151 # define ftrace_startup_sysctl() do { } while (0)
5152 # define ftrace_shutdown_sysctl() do { } while (0)
5155 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
5160 static void ftrace_update_trampoline(struct ftrace_ops *ops)
5164 #endif /* CONFIG_DYNAMIC_FTRACE */
5166 __init void ftrace_init_global_array_ops(struct trace_array *tr)
5168 tr->ops = &global_ops;
5169 tr->ops->private = tr;
5172 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
5174 /* If we filter on pids, update to use the pid function */
5175 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
5176 if (WARN_ON(tr->ops->func != ftrace_stub))
5177 printk("ftrace ops had %pS for function\n",
5180 tr->ops->func = func;
5181 tr->ops->private = tr;
5184 void ftrace_reset_array_ops(struct trace_array *tr)
5186 tr->ops->func = ftrace_stub;
5190 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5191 struct ftrace_ops *ignored, struct pt_regs *regs)
5193 struct ftrace_ops *op;
5196 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5201 * Some of the ops may be dynamically allocated,
5202 * they must be freed after a synchronize_sched().
5204 preempt_disable_notrace();
5206 do_for_each_ftrace_op(op, ftrace_ops_list) {
5208 * Check the following for each ops before calling their func:
5209 * if RCU flag is set, then rcu_is_watching() must be true
5210 * if PER_CPU is set, then ftrace_function_local_disable()
5212 * Otherwise test if the ip matches the ops filter
5214 * If any of the above fails then the op->func() is not executed.
5216 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
5217 (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5218 !ftrace_function_local_disabled(op)) &&
5219 ftrace_ops_test(op, ip, regs)) {
5221 if (FTRACE_WARN_ON(!op->func)) {
5222 pr_warn("op=%p %pS\n", op, op);
5225 op->func(ip, parent_ip, op, regs);
5227 } while_for_each_ftrace_op(op);
5229 preempt_enable_notrace();
5230 trace_clear_recursion(bit);
5234 * Some archs only support passing ip and parent_ip. Even though
5235 * the list function ignores the op parameter, we do not want any
5236 * C side effects, where a function is called without the caller
5237 * sending a third parameter.
5238 * Archs are to support both the regs and ftrace_ops at the same time.
5239 * If they support ftrace_ops, it is assumed they support regs.
5240 * If call backs want to use regs, they must either check for regs
5241 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
5242 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
5243 * An architecture can pass partial regs with ftrace_ops and still
5244 * set the ARCH_SUPPORTS_FTRACE_OPS.
5246 #if ARCH_SUPPORTS_FTRACE_OPS
5247 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
5248 struct ftrace_ops *op, struct pt_regs *regs)
5250 __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
5253 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
5255 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
5260 * If there's only one function registered but it does not support
5261 * recursion, needs RCU protection and/or requires per cpu handling, then
5262 * this function will be called by the mcount trampoline.
5264 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
5265 struct ftrace_ops *op, struct pt_regs *regs)
5269 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
5272 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
5276 preempt_disable_notrace();
5278 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
5279 !ftrace_function_local_disabled(op)) {
5280 op->func(ip, parent_ip, op, regs);
5283 preempt_enable_notrace();
5284 trace_clear_recursion(bit);
5288 * ftrace_ops_get_func - get the function a trampoline should call
5289 * @ops: the ops to get the function for
5291 * Normally the mcount trampoline will call the ops->func, but there
5292 * are times that it should not. For example, if the ops does not
5293 * have its own recursion protection, then it should call the
5294 * ftrace_ops_recurs_func() instead.
5296 * Returns the function that the trampoline should call for @ops.
5298 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
5301 * If the function does not handle recursion, needs to be RCU safe,
5302 * or does per cpu logic, then we need to call the assist handler.
5304 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
5305 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
5306 return ftrace_ops_assist_func;
5311 static void clear_ftrace_swapper(void)
5313 struct task_struct *p;
5317 for_each_online_cpu(cpu) {
5319 clear_tsk_trace_trace(p);
5324 static void set_ftrace_swapper(void)
5326 struct task_struct *p;
5330 for_each_online_cpu(cpu) {
5332 set_tsk_trace_trace(p);
5337 static void clear_ftrace_pid(struct pid *pid)
5339 struct task_struct *p;
5342 do_each_pid_task(pid, PIDTYPE_PID, p) {
5343 clear_tsk_trace_trace(p);
5344 } while_each_pid_task(pid, PIDTYPE_PID, p);
5350 static void set_ftrace_pid(struct pid *pid)
5352 struct task_struct *p;
5355 do_each_pid_task(pid, PIDTYPE_PID, p) {
5356 set_tsk_trace_trace(p);
5357 } while_each_pid_task(pid, PIDTYPE_PID, p);
5361 static void clear_ftrace_pid_task(struct pid *pid)
5363 if (pid == ftrace_swapper_pid)
5364 clear_ftrace_swapper();
5366 clear_ftrace_pid(pid);
5369 static void set_ftrace_pid_task(struct pid *pid)
5371 if (pid == ftrace_swapper_pid)
5372 set_ftrace_swapper();
5374 set_ftrace_pid(pid);
5377 static int ftrace_pid_add(int p)
5380 struct ftrace_pid *fpid;
5383 mutex_lock(&ftrace_lock);
5386 pid = ftrace_swapper_pid;
5388 pid = find_get_pid(p);
5395 list_for_each_entry(fpid, &ftrace_pids, list)
5396 if (fpid->pid == pid)
5401 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
5405 list_add(&fpid->list, &ftrace_pids);
5408 set_ftrace_pid_task(pid);
5410 ftrace_update_pid_func();
5412 ftrace_startup_all(0);
5414 mutex_unlock(&ftrace_lock);
5418 if (pid != ftrace_swapper_pid)
5422 mutex_unlock(&ftrace_lock);
5426 static void ftrace_pid_reset(void)
5428 struct ftrace_pid *fpid, *safe;
5430 mutex_lock(&ftrace_lock);
5431 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
5432 struct pid *pid = fpid->pid;
5434 clear_ftrace_pid_task(pid);
5436 list_del(&fpid->list);
5440 ftrace_update_pid_func();
5441 ftrace_startup_all(0);
5443 mutex_unlock(&ftrace_lock);
5446 static void *fpid_start(struct seq_file *m, loff_t *pos)
5448 mutex_lock(&ftrace_lock);
5450 if (!ftrace_pids_enabled() && (!*pos))
5453 return seq_list_start(&ftrace_pids, *pos);
5456 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5461 return seq_list_next(v, &ftrace_pids, pos);
5464 static void fpid_stop(struct seq_file *m, void *p)
5466 mutex_unlock(&ftrace_lock);
5469 static int fpid_show(struct seq_file *m, void *v)
5471 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
5473 if (v == (void *)1) {
5474 seq_puts(m, "no pid\n");
5478 if (fpid->pid == ftrace_swapper_pid)
5479 seq_puts(m, "swapper tasks\n");
5481 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
5486 static const struct seq_operations ftrace_pid_sops = {
5487 .start = fpid_start,
5494 ftrace_pid_open(struct inode *inode, struct file *file)
5498 if ((file->f_mode & FMODE_WRITE) &&
5499 (file->f_flags & O_TRUNC))
5502 if (file->f_mode & FMODE_READ)
5503 ret = seq_open(file, &ftrace_pid_sops);
5509 ftrace_pid_write(struct file *filp, const char __user *ubuf,
5510 size_t cnt, loff_t *ppos)
5516 if (cnt >= sizeof(buf))
5519 if (copy_from_user(&buf, ubuf, cnt))
5525 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
5526 * to clean the filter quietly.
5528 tmp = strstrip(buf);
5529 if (strlen(tmp) == 0)
5532 ret = kstrtol(tmp, 10, &val);
5536 ret = ftrace_pid_add(val);
5538 return ret ? ret : cnt;
5542 ftrace_pid_release(struct inode *inode, struct file *file)
5544 if (file->f_mode & FMODE_READ)
5545 seq_release(inode, file);
5550 static const struct file_operations ftrace_pid_fops = {
5551 .open = ftrace_pid_open,
5552 .write = ftrace_pid_write,
5554 .llseek = tracing_lseek,
5555 .release = ftrace_pid_release,
5558 static __init int ftrace_init_tracefs(void)
5560 struct dentry *d_tracer;
5562 d_tracer = tracing_init_dentry();
5563 if (IS_ERR(d_tracer))
5566 ftrace_init_dyn_tracefs(d_tracer);
5568 trace_create_file("set_ftrace_pid", 0644, d_tracer,
5569 NULL, &ftrace_pid_fops);
5571 ftrace_profile_tracefs(d_tracer);
5575 fs_initcall(ftrace_init_tracefs);
5578 * ftrace_kill - kill ftrace
5580 * This function should be used by panic code. It stops ftrace
5581 * but in a not so nice way. If you need to simply kill ftrace
5582 * from a non-atomic section, use ftrace_kill.
5584 void ftrace_kill(void)
5586 ftrace_disabled = 1;
5588 clear_ftrace_function();
5592 * Test if ftrace is dead or not.
5594 int ftrace_is_dead(void)
5596 return ftrace_disabled;
5600 * register_ftrace_function - register a function for profiling
5601 * @ops - ops structure that holds the function for profiling.
5603 * Register a function to be called by all functions in the
5606 * Note: @ops->func and all the functions it calls must be labeled
5607 * with "notrace", otherwise it will go into a
5610 int register_ftrace_function(struct ftrace_ops *ops)
5614 ftrace_ops_init(ops);
5616 mutex_lock(&ftrace_lock);
5618 ret = ftrace_startup(ops, 0);
5620 mutex_unlock(&ftrace_lock);
5624 EXPORT_SYMBOL_GPL(register_ftrace_function);
5627 * unregister_ftrace_function - unregister a function for profiling.
5628 * @ops - ops structure that holds the function to unregister
5630 * Unregister a function that was added to be called by ftrace profiling.
5632 int unregister_ftrace_function(struct ftrace_ops *ops)
5636 mutex_lock(&ftrace_lock);
5637 ret = ftrace_shutdown(ops, 0);
5638 mutex_unlock(&ftrace_lock);
5642 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5645 ftrace_enable_sysctl(struct ctl_table *table, int write,
5646 void __user *buffer, size_t *lenp,
5651 mutex_lock(&ftrace_lock);
5653 if (unlikely(ftrace_disabled))
5656 ret = proc_dointvec(table, write, buffer, lenp, ppos);
5658 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5661 last_ftrace_enabled = !!ftrace_enabled;
5663 if (ftrace_enabled) {
5665 /* we are starting ftrace again */
5666 if (ftrace_ops_list != &ftrace_list_end)
5667 update_ftrace_function();
5669 ftrace_startup_sysctl();
5672 /* stopping ftrace calls (just send to ftrace_stub) */
5673 ftrace_trace_function = ftrace_stub;
5675 ftrace_shutdown_sysctl();
5679 mutex_unlock(&ftrace_lock);
5683 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5685 static struct ftrace_ops graph_ops = {
5686 .func = ftrace_stub,
5687 .flags = FTRACE_OPS_FL_RECURSION_SAFE |
5688 FTRACE_OPS_FL_INITIALIZED |
5691 #ifdef FTRACE_GRAPH_TRAMP_ADDR
5692 .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
5693 /* trampoline_size is only needed for dynamically allocated tramps */
5695 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5698 void ftrace_graph_sleep_time_control(bool enable)
5700 fgraph_sleep_time = enable;
5703 void ftrace_graph_graph_time_control(bool enable)
5705 fgraph_graph_time = enable;
5708 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5713 /* The callbacks that hook a function */
5714 trace_func_graph_ret_t ftrace_graph_return =
5715 (trace_func_graph_ret_t)ftrace_stub;
5716 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5717 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5719 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5720 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5724 unsigned long flags;
5725 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5726 struct task_struct *g, *t;
5728 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5729 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5730 * sizeof(struct ftrace_ret_stack),
5732 if (!ret_stack_list[i]) {
5740 read_lock_irqsave(&tasklist_lock, flags);
5741 do_each_thread(g, t) {
5747 if (t->ret_stack == NULL) {
5748 atomic_set(&t->tracing_graph_pause, 0);
5749 atomic_set(&t->trace_overrun, 0);
5750 t->curr_ret_stack = -1;
5751 /* Make sure the tasks see the -1 first: */
5753 t->ret_stack = ret_stack_list[start++];
5755 } while_each_thread(g, t);
5758 read_unlock_irqrestore(&tasklist_lock, flags);
5760 for (i = start; i < end; i++)
5761 kfree(ret_stack_list[i]);
5766 ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
5767 struct task_struct *prev, struct task_struct *next)
5769 unsigned long long timestamp;
5773 * Does the user want to count the time a function was asleep.
5774 * If so, do not update the time stamps.
5776 if (fgraph_sleep_time)
5779 timestamp = trace_clock_local();
5781 prev->ftrace_timestamp = timestamp;
5783 /* only process tasks that we timestamped */
5784 if (!next->ftrace_timestamp)
5788 * Update all the counters in next to make up for the
5789 * time next was sleeping.
5791 timestamp -= next->ftrace_timestamp;
5793 for (index = next->curr_ret_stack; index >= 0; index--)
5794 next->ret_stack[index].calltime += timestamp;
5797 /* Allocate a return stack for each task */
5798 static int start_graph_tracing(void)
5800 struct ftrace_ret_stack **ret_stack_list;
5803 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5804 sizeof(struct ftrace_ret_stack *),
5807 if (!ret_stack_list)
5810 /* The cpu_boot init_task->ret_stack will never be freed */
5811 for_each_online_cpu(cpu) {
5812 if (!idle_task(cpu)->ret_stack)
5813 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5817 ret = alloc_retstack_tasklist(ret_stack_list);
5818 } while (ret == -EAGAIN);
5821 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5823 pr_info("ftrace_graph: Couldn't activate tracepoint"
5824 " probe to kernel_sched_switch\n");
5827 kfree(ret_stack_list);
5832 * Hibernation protection.
5833 * The state of the current task is too much unstable during
5834 * suspend/restore to disk. We want to protect against that.
5837 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5841 case PM_HIBERNATION_PREPARE:
5842 pause_graph_tracing();
5845 case PM_POST_HIBERNATION:
5846 unpause_graph_tracing();
5852 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5854 if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5856 return __ftrace_graph_entry(trace);
5860 * The function graph tracer should only trace the functions defined
5861 * by set_ftrace_filter and set_ftrace_notrace. If another function
5862 * tracer ops is registered, the graph tracer requires testing the
5863 * function against the global ops, and not just trace any function
5864 * that any ftrace_ops registered.
5866 static void update_function_graph_func(void)
5868 struct ftrace_ops *op;
5869 bool do_test = false;
5872 * The graph and global ops share the same set of functions
5873 * to test. If any other ops is on the list, then
5874 * the graph tracing needs to test if its the function
5877 do_for_each_ftrace_op(op, ftrace_ops_list) {
5878 if (op != &global_ops && op != &graph_ops &&
5879 op != &ftrace_list_end) {
5881 /* in double loop, break out with goto */
5884 } while_for_each_ftrace_op(op);
5887 ftrace_graph_entry = ftrace_graph_entry_test;
5889 ftrace_graph_entry = __ftrace_graph_entry;
5892 static struct notifier_block ftrace_suspend_notifier = {
5893 .notifier_call = ftrace_suspend_notifier_call,
5896 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5897 trace_func_graph_ent_t entryfunc)
5901 mutex_lock(&ftrace_lock);
5903 /* we currently allow only one tracer registered at a time */
5904 if (ftrace_graph_active) {
5909 register_pm_notifier(&ftrace_suspend_notifier);
5911 ftrace_graph_active++;
5912 ret = start_graph_tracing();
5914 ftrace_graph_active--;
5918 ftrace_graph_return = retfunc;
5921 * Update the indirect function to the entryfunc, and the
5922 * function that gets called to the entry_test first. Then
5923 * call the update fgraph entry function to determine if
5924 * the entryfunc should be called directly or not.
5926 __ftrace_graph_entry = entryfunc;
5927 ftrace_graph_entry = ftrace_graph_entry_test;
5928 update_function_graph_func();
5930 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5932 mutex_unlock(&ftrace_lock);
5936 void unregister_ftrace_graph(void)
5938 mutex_lock(&ftrace_lock);
5940 if (unlikely(!ftrace_graph_active))
5943 ftrace_graph_active--;
5944 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5945 ftrace_graph_entry = ftrace_graph_entry_stub;
5946 __ftrace_graph_entry = ftrace_graph_entry_stub;
5947 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5948 unregister_pm_notifier(&ftrace_suspend_notifier);
5949 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5951 #ifdef CONFIG_DYNAMIC_FTRACE
5953 * Function graph does not allocate the trampoline, but
5954 * other global_ops do. We need to reset the ALLOC_TRAMP flag
5957 global_ops.trampoline = save_global_trampoline;
5958 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
5959 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
5963 mutex_unlock(&ftrace_lock);
5966 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5969 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5971 atomic_set(&t->tracing_graph_pause, 0);
5972 atomic_set(&t->trace_overrun, 0);
5973 t->ftrace_timestamp = 0;
5974 /* make curr_ret_stack visible before we add the ret_stack */
5976 t->ret_stack = ret_stack;
5980 * Allocate a return stack for the idle task. May be the first
5981 * time through, or it may be done by CPU hotplug online.
5983 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5985 t->curr_ret_stack = -1;
5987 * The idle task has no parent, it either has its own
5988 * stack or no stack at all.
5991 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5993 if (ftrace_graph_active) {
5994 struct ftrace_ret_stack *ret_stack;
5996 ret_stack = per_cpu(idle_ret_stack, cpu);
5998 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5999 * sizeof(struct ftrace_ret_stack),
6003 per_cpu(idle_ret_stack, cpu) = ret_stack;
6005 graph_init_task(t, ret_stack);
6009 /* Allocate a return stack for newly created task */
6010 void ftrace_graph_init_task(struct task_struct *t)
6012 /* Make sure we do not use the parent ret_stack */
6013 t->ret_stack = NULL;
6014 t->curr_ret_stack = -1;
6016 if (ftrace_graph_active) {
6017 struct ftrace_ret_stack *ret_stack;
6019 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
6020 * sizeof(struct ftrace_ret_stack),
6024 graph_init_task(t, ret_stack);
6028 void ftrace_graph_exit_task(struct task_struct *t)
6030 struct ftrace_ret_stack *ret_stack = t->ret_stack;
6032 t->ret_stack = NULL;
6033 /* NULL must become visible to IRQs before we free it: */