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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 * @mdata: pointer of type struct marker
23 * @private_data: caller site private data
24 * @fmt: format string
25 * @...: variable argument list
26 *
27 * Type of marker probe functions. They receive the mdata and need to parse the
28 * format string to recover the variable argument list.
29 */
30typedef void marker_probe_func(const struct marker *mdata,
31 void *private_data, const char *fmt, ...);
32
33struct marker {
34 const char *name; /* Marker name */
35 const char *format; /* Marker format string, describing the
36 * variable argument list.
37 */
38 char state; /* Marker state. */
39 marker_probe_func *call;/* Probe handler function pointer */
40 void *private; /* Private probe data */
41} __attribute__((aligned(8)));
42
43#ifdef CONFIG_MARKERS
44
45/*
46 * Note : the empty asm volatile with read constraint is used here instead of a
47 * "used" attribute to fix a gcc 4.1.x bug.
48 * Make sure the alignment of the structure in the __markers section will
49 * not add unwanted padding between the beginning of the section and the
50 * structure. Force alignment to the same alignment as the section start.
51 */
52#define __trace_mark(name, call_data, format, args...) \
53 do { \
54 static const char __mstrtab_name_##name[] \
55 __attribute__((section("__markers_strings"))) \
56 = #name; \
57 static const char __mstrtab_format_##name[] \
58 __attribute__((section("__markers_strings"))) \
59 = format; \
60 static struct marker __mark_##name \
61 __attribute__((section("__markers"), aligned(8))) = \
62 { __mstrtab_name_##name, __mstrtab_format_##name, \
63 0, __mark_empty_function, NULL }; \
64 __mark_check_format(format, ## args); \
65 if (unlikely(__mark_##name.state)) { \
66 preempt_disable(); \
67 (*__mark_##name.call) \
68 (&__mark_##name, call_data, \
69 format, ## args); \
70 preempt_enable(); \
71 } \
72 } while (0)
73
74extern void marker_update_probe_range(struct marker *begin,
75 struct marker *end, struct module *probe_module, int *refcount);
76#else /* !CONFIG_MARKERS */
77#define __trace_mark(name, call_data, format, args...) \
78 __mark_check_format(format, ## args)
79static inline void marker_update_probe_range(struct marker *begin,
80 struct marker *end, struct module *probe_module, int *refcount)
81{ }
82#endif /* CONFIG_MARKERS */
83
84/**
85 * trace_mark - Marker
86 * @name: marker name, not quoted.
87 * @format: format string
88 * @args...: variable argument list
89 *
90 * Places a marker.
91 */
92#define trace_mark(name, format, args...) \
93 __trace_mark(name, NULL, format, ## args)
94
95#define MARK_MAX_FORMAT_LEN 1024
96
97/**
98 * MARK_NOARGS - Format string for a marker with no argument.
99 */
100#define MARK_NOARGS " "
101
102/* To be used for string format validity checking with gcc */
103static inline void __printf(1, 2) __mark_check_format(const char *fmt, ...)
104{
105}
106
107extern marker_probe_func __mark_empty_function;
108
109/*
110 * Connect a probe to a marker.
111 * private data pointer must be a valid allocated memory address, or NULL.
112 */
113extern int marker_probe_register(const char *name, const char *format,
114 marker_probe_func *probe, void *private);
115
116/*
117 * Returns the private data given to marker_probe_register.
118 */
119extern void *marker_probe_unregister(const char *name);
120/*
121 * Unregister a marker by providing the registered private data.
122 */
123extern void *marker_probe_unregister_private_data(void *private);
124
125extern int marker_arm(const char *name);
126extern int marker_disarm(const char *name);
127extern void *marker_get_private_data(const char *name);
128
129#endif