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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 /* Probe wrapper */
48 void (*call)(const struct marker *mdata, void *call_private, ...);
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 * The "generic" argument controls which marker enabling mechanism must be used.
63 * If generic is true, a variable read is used.
64 * If generic is false, immediate values are used.
65 */
66#define __trace_mark(generic, name, call_private, format, args...) \
67 do { \
68 static const char __mstrtab_##name[] \
69 __attribute__((section("__markers_strings"))) \
70 = #name "\0" format; \
71 static struct marker __mark_##name \
72 __attribute__((section("__markers"), aligned(8))) = \
73 { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
74 0, 0, marker_probe_cb, \
75 { __mark_empty_function, NULL}, NULL }; \
76 __mark_check_format(format, ## args); \
77 if (unlikely(__mark_##name.state)) { \
78 (*__mark_##name.call) \
79 (&__mark_##name, call_private, ## args);\
80 } \
81 } while (0)
82
83extern void marker_update_probe_range(struct marker *begin,
84 struct marker *end);
85#else /* !CONFIG_MARKERS */
86#define __trace_mark(generic, name, call_private, format, args...) \
87 __mark_check_format(format, ## args)
88static inline void marker_update_probe_range(struct marker *begin,
89 struct marker *end)
90{ }
91#endif /* CONFIG_MARKERS */
92
93/**
94 * trace_mark - Marker using code patching
95 * @name: marker name, not quoted.
96 * @format: format string
97 * @args...: variable argument list
98 *
99 * Places a marker using optimized code patching technique (imv_read())
100 * to be enabled when immediate values are present.
101 */
102#define trace_mark(name, format, args...) \
103 __trace_mark(0, name, NULL, format, ## args)
104
105/**
106 * _trace_mark - Marker using variable read
107 * @name: marker name, not quoted.
108 * @format: format string
109 * @args...: variable argument list
110 *
111 * Places a marker using a standard memory read (_imv_read()) to be
112 * enabled. Should be used for markers in code paths where instruction
113 * modification based enabling is not welcome. (__init and __exit functions,
114 * lockdep, some traps, printk).
115 */
116#define _trace_mark(name, format, args...) \
117 __trace_mark(1, name, NULL, format, ## args)
118
119/**
120 * MARK_NOARGS - Format string for a marker with no argument.
121 */
122#define MARK_NOARGS " "
123
124/* To be used for string format validity checking with gcc */
125static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
126{
127}
128
129#define __mark_check_format(format, args...) \
130 do { \
131 if (0) \
132 ___mark_check_format(format, ## args); \
133 } while (0)
134
135extern marker_probe_func __mark_empty_function;
136
137extern void marker_probe_cb(const struct marker *mdata,
138 void *call_private, ...);
139extern void marker_probe_cb_noarg(const struct marker *mdata,
140 void *call_private, ...);
141
142/*
143 * Connect a probe to a marker.
144 * private data pointer must be a valid allocated memory address, or NULL.
145 */
146extern int marker_probe_register(const char *name, const char *format,
147 marker_probe_func *probe, void *probe_private);
148
149/*
150 * Returns the private data given to marker_probe_register.
151 */
152extern int marker_probe_unregister(const char *name,
153 marker_probe_func *probe, void *probe_private);
154/*
155 * Unregister a marker by providing the registered private data.
156 */
157extern int marker_probe_unregister_private_data(marker_probe_func *probe,
158 void *probe_private);
159
160extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
161 int num);
162
163/*
164 * marker_synchronize_unregister must be called between the last marker probe
165 * unregistration and the end of module exit to make sure there is no caller
166 * executing a probe when it is freed.
167 */
168#define marker_synchronize_unregister() synchronize_sched()
169
170#endif