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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 | \ | |
43 | rcu_read_lock_sched(); \ | |
44 | it_func = rcu_dereference((tp)->funcs); \ | |
45 | if (it_func) { \ | |
46 | do { \ | |
47 | ((void(*)(proto))(*it_func))(args); \ | |
48 | } while (*(++it_func)); \ | |
49 | } \ | |
50 | rcu_read_unlock_sched(); \ | |
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"))) \ | |
63 | = #name ":" #proto; \ | |
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 | { \ | |
73 | return tracepoint_probe_register(#name ":" #proto, \ | |
74 | (void *)probe); \ | |
75 | } \ | |
76 | static inline void unregister_trace_##name(void (*probe)(proto))\ | |
77 | { \ | |
78 | tracepoint_probe_unregister(#name ":" #proto, \ | |
79 | (void *)probe); \ | |
80 | } | |
81 | ||
82 | extern void tracepoint_update_probe_range(struct tracepoint *begin, | |
83 | struct tracepoint *end); | |
84 | ||
85 | #else /* !CONFIG_TRACEPOINTS */ | |
86 | #define DEFINE_TRACE(name, proto, args) \ | |
87 | static inline void _do_trace_##name(struct tracepoint *tp, proto) \ | |
88 | { } \ | |
89 | static inline void trace_##name(proto) \ | |
90 | { } \ | |
91 | static inline int register_trace_##name(void (*probe)(proto)) \ | |
92 | { \ | |
93 | return -ENOSYS; \ | |
94 | } \ | |
95 | static inline void unregister_trace_##name(void (*probe)(proto))\ | |
96 | { } | |
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 | ||
115 | struct tracepoint_iter { | |
116 | struct module *module; | |
117 | struct tracepoint *tracepoint; | |
118 | }; | |
119 | ||
120 | extern void tracepoint_iter_start(struct tracepoint_iter *iter); | |
121 | extern void tracepoint_iter_next(struct tracepoint_iter *iter); | |
122 | extern void tracepoint_iter_stop(struct tracepoint_iter *iter); | |
123 | extern void tracepoint_iter_reset(struct tracepoint_iter *iter); | |
124 | extern int tracepoint_get_iter_range(struct tracepoint **tracepoint, | |
125 | struct tracepoint *begin, struct tracepoint *end); | |
126 | ||
f2461fc8 MD |
127 | /* |
128 | * tracepoint_synchronize_unregister must be called between the last tracepoint | |
129 | * probe unregistration and the end of module exit to make sure there is no | |
130 | * caller executing a probe when it is freed. | |
131 | */ | |
231375cc MD |
132 | static inline void tracepoint_synchronize_unregister(void) |
133 | { | |
134 | synchronize_sched(); | |
135 | } | |
f2461fc8 | 136 | |
97e1c18e | 137 | #endif |