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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 <stdarg.h>
16#include <linux/types.h>
17
18struct module;
19struct marker;
20
21/**
22 * marker_probe_func - Type of a marker probe function
23 * @probe_private: probe private data
24 * @call_private: call site private data
25 * @fmt: format string
26 * @args: variable argument list pointer. Use a pointer to overcome C's
27 * inability to pass this around as a pointer in a portable manner in
28 * the callee otherwise.
29 *
30 * Type of marker probe functions. They receive the mdata and need to parse the
31 * format string to recover the variable argument list.
32 */
33typedef void marker_probe_func(void *probe_private, void *call_private,
34 const char *fmt, va_list *args);
35
36struct marker_probe_closure {
37 marker_probe_func *func; /* Callback */
38 void *probe_private; /* Private probe data */
39};
40
41struct marker {
42 const char *name; /* Marker name */
43 const char *format; /* Marker format string, describing the
44 * variable argument list.
45 */
46 char state; /* Marker state. */
47 char ptype; /* probe type : 0 : single, 1 : multi */
48 /* Probe wrapper */
49 void (*call)(const struct marker *mdata, void *call_private, ...);
50 struct marker_probe_closure single;
51 struct marker_probe_closure *multi;
52 const char *tp_name; /* Optional tracepoint name */
53 void *tp_cb; /* Optional tracepoint callback */
54} __attribute__((aligned(8)));
55
56#ifdef CONFIG_MARKERS
57
58#define _DEFINE_MARKER(name, tp_name_str, tp_cb, format) \
59 static const char __mstrtab_##name[] \
60 __attribute__((section("__markers_strings"))) \
61 = #name "\0" format; \
62 static struct marker __mark_##name \
63 __attribute__((section("__markers"), aligned(8))) = \
64 { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
65 0, 0, marker_probe_cb, { __mark_empty_function, NULL},\
66 NULL, tp_name_str, tp_cb }
67
68#define DEFINE_MARKER(name, format) \
69 _DEFINE_MARKER(name, NULL, NULL, format)
70
71#define DEFINE_MARKER_TP(name, tp_name, tp_cb, format) \
72 _DEFINE_MARKER(name, #tp_name, tp_cb, format)
73
74/*
75 * Note : the empty asm volatile with read constraint is used here instead of a
76 * "used" attribute to fix a gcc 4.1.x bug.
77 * Make sure the alignment of the structure in the __markers section will
78 * not add unwanted padding between the beginning of the section and the
79 * structure. Force alignment to the same alignment as the section start.
80 *
81 * The "generic" argument controls which marker enabling mechanism must be used.
82 * If generic is true, a variable read is used.
83 * If generic is false, immediate values are used.
84 */
85#define __trace_mark(generic, name, call_private, format, args...) \
86 do { \
87 DEFINE_MARKER(name, format); \
88 __mark_check_format(format, ## args); \
89 if (unlikely(__mark_##name.state)) { \
90 (*__mark_##name.call) \
91 (&__mark_##name, call_private, ## args);\
92 } \
93 } while (0)
94
95#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
96 do { \
97 void __check_tp_type(void) \
98 { \
99 register_trace_##tp_name(tp_cb); \
100 } \
101 DEFINE_MARKER_TP(name, tp_name, tp_cb, format); \
102 __mark_check_format(format, ## args); \
103 (*__mark_##name.call)(&__mark_##name, call_private, \
104 ## args); \
105 } while (0)
106
107extern void marker_update_probe_range(struct marker *begin,
108 struct marker *end);
109
110#define GET_MARKER(name) (__mark_##name)
111
112#else /* !CONFIG_MARKERS */
113#define DEFINE_MARKER(name, tp_name, tp_cb, format)
114#define __trace_mark(generic, name, call_private, format, args...) \
115 __mark_check_format(format, ## args)
116#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
117 do { \
118 void __check_tp_type(void) \
119 { \
120 register_trace_##tp_name(tp_cb); \
121 } \
122 __mark_check_format(format, ## args); \
123 } while (0)
124static inline void marker_update_probe_range(struct marker *begin,
125 struct marker *end)
126{ }
127#define GET_MARKER(name)
128#endif /* CONFIG_MARKERS */
129
130/**
131 * trace_mark - Marker using code patching
132 * @name: marker name, not quoted.
133 * @format: format string
134 * @args...: variable argument list
135 *
136 * Places a marker using optimized code patching technique (imv_read())
137 * to be enabled when immediate values are present.
138 */
139#define trace_mark(name, format, args...) \
140 __trace_mark(0, name, NULL, format, ## args)
141
142/**
143 * _trace_mark - Marker using variable read
144 * @name: marker name, not quoted.
145 * @format: format string
146 * @args...: variable argument list
147 *
148 * Places a marker using a standard memory read (_imv_read()) to be
149 * enabled. Should be used for markers in code paths where instruction
150 * modification based enabling is not welcome. (__init and __exit functions,
151 * lockdep, some traps, printk).
152 */
153#define _trace_mark(name, format, args...) \
154 __trace_mark(1, name, NULL, format, ## args)
155
156/**
157 * trace_mark_tp - Marker in a tracepoint callback
158 * @name: marker name, not quoted.
159 * @tp_name: tracepoint name, not quoted.
160 * @tp_cb: tracepoint callback. Should have an associated global symbol so it
161 * is not optimized away by the compiler (should not be static).
162 * @format: format string
163 * @args...: variable argument list
164 *
165 * Places a marker in a tracepoint callback.
166 */
167#define trace_mark_tp(name, tp_name, tp_cb, format, args...) \
168 __trace_mark_tp(name, NULL, tp_name, tp_cb, format, ## args)
169
170/**
171 * MARK_NOARGS - Format string for a marker with no argument.
172 */
173#define MARK_NOARGS " "
174
175/* To be used for string format validity checking with gcc */
176static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
177{
178}
179
180#define __mark_check_format(format, args...) \
181 do { \
182 if (0) \
183 ___mark_check_format(format, ## args); \
184 } while (0)
185
186extern marker_probe_func __mark_empty_function;
187
188extern void marker_probe_cb(const struct marker *mdata,
189 void *call_private, ...);
190
191/*
192 * Connect a probe to a marker.
193 * private data pointer must be a valid allocated memory address, or NULL.
194 */
195extern int marker_probe_register(const char *name, const char *format,
196 marker_probe_func *probe, void *probe_private);
197
198/*
199 * Returns the private data given to marker_probe_register.
200 */
201extern int marker_probe_unregister(const char *name,
202 marker_probe_func *probe, void *probe_private);
203/*
204 * Unregister a marker by providing the registered private data.
205 */
206extern int marker_probe_unregister_private_data(marker_probe_func *probe,
207 void *probe_private);
208
209extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
210 int num);
211
212/*
213 * marker_synchronize_unregister must be called between the last marker probe
214 * unregistration and the first one of
215 * - the end of module exit function
216 * - the free of any resource used by the probes
217 * to ensure the code and data are valid for any possibly running probes.
218 */
219#define marker_synchronize_unregister() synchronize_sched()
220
221#endif