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97e1c18e MD |
1 | #ifndef _LINUX_TRACEPOINT_H |
2 | #define _LINUX_TRACEPOINT_H | |
3 | ||
4 | /* | |
5 | * Kernel Tracepoint API. | |
6 | * | |
7 | * See Documentation/tracepoint.txt. | |
8 | * | |
9 | * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> | |
10 | * | |
11 | * Heavily inspired from the Linux Kernel Markers. | |
12 | * | |
13 | * This file is released under the GPLv2. | |
14 | * See the file COPYING for more details. | |
15 | */ | |
16 | ||
17 | #include <linux/types.h> | |
18 | #include <linux/rcupdate.h> | |
19 | ||
20 | struct module; | |
21 | struct tracepoint; | |
22 | ||
23 | struct tracepoint { | |
24 | const char *name; /* Tracepoint name */ | |
25 | int state; /* State. */ | |
26 | void **funcs; | |
27 | } __attribute__((aligned(8))); | |
28 | ||
29 | ||
30 | #define TPPROTO(args...) args | |
31 | #define TPARGS(args...) args | |
32 | ||
33 | #ifdef CONFIG_TRACEPOINTS | |
34 | ||
35 | /* | |
36 | * it_func[0] is never NULL because there is at least one element in the array | |
37 | * when the array itself is non NULL. | |
38 | */ | |
39 | #define __DO_TRACE(tp, proto, args) \ | |
40 | do { \ | |
41 | void **it_func; \ | |
42 | \ | |
da7b3eab | 43 | rcu_read_lock_sched_notrace(); \ |
97e1c18e MD |
44 | it_func = rcu_dereference((tp)->funcs); \ |
45 | if (it_func) { \ | |
46 | do { \ | |
47 | ((void(*)(proto))(*it_func))(args); \ | |
48 | } while (*(++it_func)); \ | |
49 | } \ | |
da7b3eab | 50 | rcu_read_unlock_sched_notrace(); \ |
97e1c18e MD |
51 | } while (0) |
52 | ||
53 | /* | |
54 | * Make sure the alignment of the structure in the __tracepoints section will | |
55 | * not add unwanted padding between the beginning of the section and the | |
56 | * structure. Force alignment to the same alignment as the section start. | |
57 | */ | |
58 | #define DEFINE_TRACE(name, proto, args) \ | |
59 | static inline void trace_##name(proto) \ | |
60 | { \ | |
61 | static const char __tpstrtab_##name[] \ | |
62 | __attribute__((section("__tracepoints_strings"))) \ | |
5f382671 | 63 | = #name; \ |
97e1c18e MD |
64 | static struct tracepoint __tracepoint_##name \ |
65 | __attribute__((section("__tracepoints"), aligned(8))) = \ | |
66 | { __tpstrtab_##name, 0, NULL }; \ | |
67 | if (unlikely(__tracepoint_##name.state)) \ | |
68 | __DO_TRACE(&__tracepoint_##name, \ | |
69 | TPPROTO(proto), TPARGS(args)); \ | |
70 | } \ | |
71 | static inline int register_trace_##name(void (*probe)(proto)) \ | |
72 | { \ | |
5f382671 | 73 | return tracepoint_probe_register(#name, (void *)probe); \ |
97e1c18e | 74 | } \ |
c420970e | 75 | static inline int unregister_trace_##name(void (*probe)(proto)) \ |
97e1c18e | 76 | { \ |
5f382671 | 77 | return tracepoint_probe_unregister(#name, (void *)probe);\ |
97e1c18e MD |
78 | } |
79 | ||
80 | extern void tracepoint_update_probe_range(struct tracepoint *begin, | |
81 | struct tracepoint *end); | |
82 | ||
83 | #else /* !CONFIG_TRACEPOINTS */ | |
84 | #define DEFINE_TRACE(name, proto, args) \ | |
85 | static inline void _do_trace_##name(struct tracepoint *tp, proto) \ | |
86 | { } \ | |
87 | static inline void trace_##name(proto) \ | |
88 | { } \ | |
89 | static inline int register_trace_##name(void (*probe)(proto)) \ | |
90 | { \ | |
91 | return -ENOSYS; \ | |
92 | } \ | |
c420970e MD |
93 | static inline int unregister_trace_##name(void (*probe)(proto)) \ |
94 | { \ | |
95 | return -ENOSYS; \ | |
96 | } | |
97e1c18e MD |
97 | |
98 | static inline void tracepoint_update_probe_range(struct tracepoint *begin, | |
99 | struct tracepoint *end) | |
100 | { } | |
101 | #endif /* CONFIG_TRACEPOINTS */ | |
102 | ||
103 | /* | |
104 | * Connect a probe to a tracepoint. | |
105 | * Internal API, should not be used directly. | |
106 | */ | |
107 | extern int tracepoint_probe_register(const char *name, void *probe); | |
108 | ||
109 | /* | |
110 | * Disconnect a probe from a tracepoint. | |
111 | * Internal API, should not be used directly. | |
112 | */ | |
113 | extern int tracepoint_probe_unregister(const char *name, void *probe); | |
114 | ||
127cafbb LJ |
115 | extern int tracepoint_probe_register_noupdate(const char *name, void *probe); |
116 | extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe); | |
117 | extern void tracepoint_probe_update_all(void); | |
118 | ||
97e1c18e MD |
119 | struct tracepoint_iter { |
120 | struct module *module; | |
121 | struct tracepoint *tracepoint; | |
122 | }; | |
123 | ||
124 | extern void tracepoint_iter_start(struct tracepoint_iter *iter); | |
125 | extern void tracepoint_iter_next(struct tracepoint_iter *iter); | |
126 | extern void tracepoint_iter_stop(struct tracepoint_iter *iter); | |
127 | extern void tracepoint_iter_reset(struct tracepoint_iter *iter); | |
128 | extern int tracepoint_get_iter_range(struct tracepoint **tracepoint, | |
129 | struct tracepoint *begin, struct tracepoint *end); | |
130 | ||
f2461fc8 MD |
131 | /* |
132 | * tracepoint_synchronize_unregister must be called between the last tracepoint | |
133 | * probe unregistration and the end of module exit to make sure there is no | |
134 | * caller executing a probe when it is freed. | |
135 | */ | |
231375cc MD |
136 | static inline void tracepoint_synchronize_unregister(void) |
137 | { | |
138 | synchronize_sched(); | |
139 | } | |
f2461fc8 | 140 | |
97e1c18e | 141 | #endif |