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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
20struct module;
21struct tracepoint;
22
23struct 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
82extern 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
98static 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 */
107extern 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 */
113extern int tracepoint_probe_unregister(const char *name, void *probe);
114
115struct tracepoint_iter {
116 struct module *module;
117 struct tracepoint *tracepoint;
118};
119
120extern void tracepoint_iter_start(struct tracepoint_iter *iter);
121extern void tracepoint_iter_next(struct tracepoint_iter *iter);
122extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
123extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
124extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
125 struct tracepoint *begin, struct tracepoint *end);
126
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 */
132static inline void tracepoint_synchronize_unregister(void)
133{
134 synchronize_sched();
135}
136
137#endif