summaryrefslogtreecommitdiff
path: root/include/linux/marker.h
blob: 5df879dc3776c732dc62e017850f0eb4739429e3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
#ifndef _LINUX_MARKER_H
#define _LINUX_MARKER_H

/*
 * Code markup for dynamic and static tracing.
 *
 * See Documentation/marker.txt.
 *
 * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 *
 * This file is released under the GPLv2.
 * See the file COPYING for more details.
 */

#include <linux/types.h>

struct module;
struct marker;

/**
 * marker_probe_func - Type of a marker probe function
 * @probe_private: probe private data
 * @call_private: call site private data
 * @fmt: format string
 * @args: variable argument list pointer. Use a pointer to overcome C's
 *        inability to pass this around as a pointer in a portable manner in
 *        the callee otherwise.
 *
 * Type of marker probe functions. They receive the mdata and need to parse the
 * format string to recover the variable argument list.
 */
typedef void marker_probe_func(void *probe_private, void *call_private,
		const char *fmt, va_list *args);

struct marker_probe_closure {
	marker_probe_func *func;	/* Callback */
	void *probe_private;		/* Private probe data */
};

struct marker {
	const char *name;	/* Marker name */
	const char *format;	/* Marker format string, describing the
				 * variable argument list.
				 */
	char state;		/* Marker state. */
	char ptype;		/* probe type : 0 : single, 1 : multi */
	void (*call)(const struct marker *mdata,	/* Probe wrapper */
		void *call_private, const char *fmt, ...);
	struct marker_probe_closure single;
	struct marker_probe_closure *multi;
} __attribute__((aligned(8)));

#ifdef CONFIG_MARKERS

/*
 * Note : the empty asm volatile with read constraint is used here instead of a
 * "used" attribute to fix a gcc 4.1.x bug.
 * Make sure the alignment of the structure in the __markers section will
 * not add unwanted padding between the beginning of the section and the
 * structure. Force alignment to the same alignment as the section start.
 */
#define __trace_mark(name, call_private, format, args...)		\
	do {								\
		static const char __mstrtab_##name[]			\
		__attribute__((section("__markers_strings")))		\
		= #name "\0" format;					\
		static struct marker __mark_##name			\
		__attribute__((section("__markers"), aligned(8))) =	\
		{ __mstrtab_##name, &__mstrtab_##name[sizeof(#name)],	\
		0, 0, marker_probe_cb,					\
		{ __mark_empty_function, NULL}, NULL };			\
		__mark_check_format(format, ## args);			\
		if (unlikely(__mark_##name.state)) {			\
			(*__mark_##name.call)				\
				(&__mark_##name, call_private,		\
				format, ## args);			\
		}							\
	} while (0)

extern void marker_update_probe_range(struct marker *begin,
	struct marker *end);
#else /* !CONFIG_MARKERS */
#define __trace_mark(name, call_private, format, args...) \
		__mark_check_format(format, ## args)
static inline void marker_update_probe_range(struct marker *begin,
	struct marker *end)
{ }
#endif /* CONFIG_MARKERS */

/**
 * trace_mark - Marker
 * @name: marker name, not quoted.
 * @format: format string
 * @args...: variable argument list
 *
 * Places a marker.
 */
#define trace_mark(name, format, args...) \
	__trace_mark(name, NULL, format, ## args)

/**
 * MARK_NOARGS - Format string for a marker with no argument.
 */
#define MARK_NOARGS " "

/* To be used for string format validity checking with gcc */
static inline void __printf(1, 2) __mark_check_format(const char *fmt, ...)
{
}

extern marker_probe_func __mark_empty_function;

extern void marker_probe_cb(const struct marker *mdata,
	void *call_private, const char *fmt, ...);
extern void marker_probe_cb_noarg(const struct marker *mdata,
	void *call_private, const char *fmt, ...);

/*
 * Connect a probe to a marker.
 * private data pointer must be a valid allocated memory address, or NULL.
 */
extern int marker_probe_register(const char *name, const char *format,
				marker_probe_func *probe, void *probe_private);

/*
 * Returns the private data given to marker_probe_register.
 */
extern int marker_probe_unregister(const char *name,
	marker_probe_func *probe, void *probe_private);
/*
 * Unregister a marker by providing the registered private data.
 */
extern int marker_probe_unregister_private_data(marker_probe_func *probe,
	void *probe_private);

extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
	int num);

#endif