aboutsummaryrefslogtreecommitdiff
path: root/include/linux/marker.h
blob: b85e74ca782ff1fb026732717ffa8db5d688a1d9 (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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
#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 <stdarg.h>
#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 */
				/* Probe wrapper */
	void (*call)(const struct marker *mdata, void *call_private, ...);
	struct marker_probe_closure single;
	struct marker_probe_closure *multi;
	const char *tp_name;	/* Optional tracepoint name */
	void *tp_cb;		/* Optional tracepoint callback */
} __attribute__((aligned(8)));

#ifdef CONFIG_MARKERS

#define _DEFINE_MARKER(name, tp_name_str, tp_cb, format)		\
		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, tp_name_str, tp_cb }

#define DEFINE_MARKER(name, format)					\
		_DEFINE_MARKER(name, NULL, NULL, format)

#define DEFINE_MARKER_TP(name, tp_name, tp_cb, format)			\
		_DEFINE_MARKER(name, #tp_name, tp_cb, format)

/*
 * 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.
 *
 * The "generic" argument controls which marker enabling mechanism must be used.
 * If generic is true, a variable read is used.
 * If generic is false, immediate values are used.
 */
#define __trace_mark(generic, name, call_private, format, args...)	\
	do {								\
		DEFINE_MARKER(name, format);				\
		__mark_check_format(format, ## args);			\
		if (unlikely(__mark_##name.state)) {			\
			(*__mark_##name.call)				\
				(&__mark_##name, call_private, ## args);\
		}							\
	} while (0)

#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
	do {								\
		void __check_tp_type(void)				\
		{							\
			register_trace_##tp_name(tp_cb);		\
		}							\
		DEFINE_MARKER_TP(name, tp_name, tp_cb, format);		\
		__mark_check_format(format, ## args);			\
		(*__mark_##name.call)(&__mark_##name, call_private,	\
					## args);			\
	} while (0)

extern void marker_update_probe_range(struct marker *begin,
	struct marker *end);

#define GET_MARKER(name)	(__mark_##name)

#else /* !CONFIG_MARKERS */
#define DEFINE_MARKER(name, tp_name, tp_cb, format)
#define __trace_mark(generic, name, call_private, format, args...) \
		__mark_check_format(format, ## args)
#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
	do {								\
		void __check_tp_type(void)				\
		{							\
			register_trace_##tp_name(tp_cb);		\
		}							\
		__mark_check_format(format, ## args);			\
	} while (0)
static inline void marker_update_probe_range(struct marker *begin,
	struct marker *end)
{ }
#define GET_MARKER(name)
#endif /* CONFIG_MARKERS */

/**
 * trace_mark - Marker using code patching
 * @name: marker name, not quoted.
 * @format: format string
 * @args...: variable argument list
 *
 * Places a marker using optimized code patching technique (imv_read())
 * to be enabled when immediate values are present.
 */
#define trace_mark(name, format, args...) \
	__trace_mark(0, name, NULL, format, ## args)

/**
 * _trace_mark - Marker using variable read
 * @name: marker name, not quoted.
 * @format: format string
 * @args...: variable argument list
 *
 * Places a marker using a standard memory read (_imv_read()) to be
 * enabled. Should be used for markers in code paths where instruction
 * modification based enabling is not welcome. (__init and __exit functions,
 * lockdep, some traps, printk).
 */
#define _trace_mark(name, format, args...) \
	__trace_mark(1, name, NULL, format, ## args)

/**
 * trace_mark_tp - Marker in a tracepoint callback
 * @name: marker name, not quoted.
 * @tp_name: tracepoint name, not quoted.
 * @tp_cb: tracepoint callback. Should have an associated global symbol so it
 *         is not optimized away by the compiler (should not be static).
 * @format: format string
 * @args...: variable argument list
 *
 * Places a marker in a tracepoint callback.
 */
#define trace_mark_tp(name, tp_name, tp_cb, format, args...)	\
	__trace_mark_tp(name, NULL, tp_name, tp_cb, 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, ...)
{
}

#define __mark_check_format(format, args...)				\
	do {								\
		if (0)							\
			___mark_check_format(format, ## args);		\
	} while (0)

extern marker_probe_func __mark_empty_function;

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

/*
 * 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);

/*
 * marker_synchronize_unregister must be called between the last marker probe
 * unregistration and the first one of
 * - the end of module exit function
 * - the free of any resource used by the probes
 * to ensure the code and data are valid for any possibly running probes.
 */
#define marker_synchronize_unregister() synchronize_sched()

#endif