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1#ifndef _LINUX_MARKER_H
2#define _LINUX_MARKER_H
3
4/*
5 * Code markup for dynamic and static tracing.
6 *
7 * See Documentation/marker.txt.
8 *
9 * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
10 *
11 * This file is released under the GPLv2.
12 * See the file COPYING for more details.
13 */
14
15#include <linux/types.h>
16
17struct module;
18struct marker;
19
20/**
21 * marker_probe_func - Type of a marker probe function
22 * @probe_private: probe private data
23 * @call_private: call site private data
24 * @fmt: format string
25 * @args: variable argument list pointer. Use a pointer to overcome C's
26 * inability to pass this around as a pointer in a portable manner in
27 * the callee otherwise.
28 *
29 * Type of marker probe functions. They receive the mdata and need to parse the
30 * format string to recover the variable argument list.
31 */
32typedef void marker_probe_func(void *probe_private, void *call_private,
33 const char *fmt, va_list *args);
34
35struct marker_probe_closure {
36 marker_probe_func *func; /* Callback */
37 void *probe_private; /* Private probe data */
38};
39
40struct marker {
41 const char *name; /* Marker name */
42 const char *format; /* Marker format string, describing the
43 * variable argument list.
44 */
45 char state; /* Marker state. */
46 char ptype; /* probe type : 0 : single, 1 : multi */
47 void (*call)(const struct marker *mdata, /* Probe wrapper */
48 void *call_private, const char *fmt, ...);
49 struct marker_probe_closure single;
50 struct marker_probe_closure *multi;
51} __attribute__((aligned(8)));
52
53#ifdef CONFIG_MARKERS
54
55/*
56 * Note : the empty asm volatile with read constraint is used here instead of a
57 * "used" attribute to fix a gcc 4.1.x bug.
58 * Make sure the alignment of the structure in the __markers section will
59 * not add unwanted padding between the beginning of the section and the
60 * structure. Force alignment to the same alignment as the section start.
61 */
62#define __trace_mark(name, call_private, format, args...) \
63 do { \
64 static const char __mstrtab_##name[] \
65 __attribute__((section("__markers_strings"))) \
66 = #name "\0" format; \
67 static struct marker __mark_##name \
68 __attribute__((section("__markers"), aligned(8))) = \
69 { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
70 0, 0, marker_probe_cb, \
71 { __mark_empty_function, NULL}, NULL }; \
72 __mark_check_format(format, ## args); \
73 if (unlikely(__mark_##name.state)) { \
74 (*__mark_##name.call) \
75 (&__mark_##name, call_private, \
76 format, ## args); \
77 } \
78 } while (0)
79
80extern void marker_update_probe_range(struct marker *begin,
81 struct marker *end);
82#else /* !CONFIG_MARKERS */
83#define __trace_mark(name, call_private, format, args...) \
84 __mark_check_format(format, ## args)
85static inline void marker_update_probe_range(struct marker *begin,
86 struct marker *end)
87{ }
88#endif /* CONFIG_MARKERS */
89
90/**
91 * trace_mark - Marker
92 * @name: marker name, not quoted.
93 * @format: format string
94 * @args...: variable argument list
95 *
96 * Places a marker.
97 */
98#define trace_mark(name, format, args...) \
99 __trace_mark(name, NULL, format, ## args)
100
101/**
102 * MARK_NOARGS - Format string for a marker with no argument.
103 */
104#define MARK_NOARGS " "
105
106/* To be used for string format validity checking with gcc */
107static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
108{
109}
110
111#define __mark_check_format(format, args...) \
112 do { \
113 if (0) \
114 ___mark_check_format(format, ## args); \
115 } while (0)
116
117extern marker_probe_func __mark_empty_function;
118
119extern void marker_probe_cb(const struct marker *mdata,
120 void *call_private, const char *fmt, ...);
121extern void marker_probe_cb_noarg(const struct marker *mdata,
122 void *call_private, const char *fmt, ...);
123
124/*
125 * Connect a probe to a marker.
126 * private data pointer must be a valid allocated memory address, or NULL.
127 */
128extern int marker_probe_register(const char *name, const char *format,
129 marker_probe_func *probe, void *probe_private);
130
131/*
132 * Returns the private data given to marker_probe_register.
133 */
134extern int marker_probe_unregister(const char *name,
135 marker_probe_func *probe, void *probe_private);
136/*
137 * Unregister a marker by providing the registered private data.
138 */
139extern int marker_probe_unregister_private_data(marker_probe_func *probe,
140 void *probe_private);
141
142extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
143 int num);
144
145#endif