Root/drivers/staging/sep/sep_trace_events.h

1/*
2 * If TRACE_SYSTEM is defined, that will be the directory created
3 * in the ftrace directory under /sys/kernel/debug/tracing/events/<system>
4 *
5 * The define_trace.h below will also look for a file name of
6 * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
7 * In this case, it would look for sample.h
8 *
9 * If the header name will be different than the system name
10 * (as in this case), then you can override the header name that
11 * define_trace.h will look up by defining TRACE_INCLUDE_FILE
12 *
13 * This file is called trace-events-sample.h but we want the system
14 * to be called "sample". Therefore we must define the name of this
15 * file:
16 *
17 * #define TRACE_INCLUDE_FILE trace-events-sample
18 *
19 * As we do an the bottom of this file.
20 *
21 * Notice that TRACE_SYSTEM should be defined outside of #if
22 * protection, just like TRACE_INCLUDE_FILE.
23 */
24#undef TRACE_SYSTEM
25#define TRACE_SYSTEM sep
26
27/*
28 * Notice that this file is not protected like a normal header.
29 * We also must allow for rereading of this file. The
30 *
31 * || defined(TRACE_HEADER_MULTI_READ)
32 *
33 * serves this purpose.
34 */
35#if !defined(_TRACE_SEP_EVENTS_H) || defined(TRACE_HEADER_MULTI_READ)
36#define _TRACE_SEP_EVENTS_H
37
38#ifdef SEP_PERF_DEBUG
39#define SEP_TRACE_FUNC_IN() trace_sep_func_start(__func__, 0)
40#define SEP_TRACE_FUNC_OUT(branch) trace_sep_func_end(__func__, branch)
41#define SEP_TRACE_EVENT(branch) trace_sep_misc_event(__func__, branch)
42#else
43#define SEP_TRACE_FUNC_IN()
44#define SEP_TRACE_FUNC_OUT(branch)
45#define SEP_TRACE_EVENT(branch)
46#endif
47
48
49/*
50 * All trace headers should include tracepoint.h, until we finally
51 * make it into a standard header.
52 */
53#include <linux/tracepoint.h>
54
55/*
56 * The TRACE_EVENT macro is broken up into 5 parts.
57 *
58 * name: name of the trace point. This is also how to enable the tracepoint.
59 * A function called trace_foo_bar() will be created.
60 *
61 * proto: the prototype of the function trace_foo_bar()
62 * Here it is trace_foo_bar(char *foo, int bar).
63 *
64 * args: must match the arguments in the prototype.
65 * Here it is simply "foo, bar".
66 *
67 * struct: This defines the way the data will be stored in the ring buffer.
68 * There are currently two types of elements. __field and __array.
69 * a __field is broken up into (type, name). Where type can be any
70 * type but an array.
71 * For an array. there are three fields. (type, name, size). The
72 * type of elements in the array, the name of the field and the size
73 * of the array.
74 *
75 * __array( char, foo, 10) is the same as saying char foo[10].
76 *
77 * fast_assign: This is a C like function that is used to store the items
78 * into the ring buffer.
79 *
80 * printk: This is a way to print out the data in pretty print. This is
81 * useful if the system crashes and you are logging via a serial line,
82 * the data can be printed to the console using this "printk" method.
83 *
84 * Note, that for both the assign and the printk, __entry is the handler
85 * to the data structure in the ring buffer, and is defined by the
86 * TP_STRUCT__entry.
87 */
88TRACE_EVENT(sep_func_start,
89
90    TP_PROTO(const char *name, int branch),
91
92    TP_ARGS(name, branch),
93
94    TP_STRUCT__entry(
95        __array(char, name, 20)
96        __field(int, branch)
97    ),
98
99    TP_fast_assign(
100        strncpy(__entry->name, name, 20);
101        __entry->branch = branch;
102    ),
103
104    TP_printk("func_start %s %d", __entry->name, __entry->branch)
105);
106
107TRACE_EVENT(sep_func_end,
108
109    TP_PROTO(const char *name, int branch),
110
111    TP_ARGS(name, branch),
112
113    TP_STRUCT__entry(
114        __array(char, name, 20)
115        __field(int, branch)
116    ),
117
118    TP_fast_assign(
119        strncpy(__entry->name, name, 20);
120        __entry->branch = branch;
121    ),
122
123    TP_printk("func_end %s %d", __entry->name, __entry->branch)
124);
125
126TRACE_EVENT(sep_misc_event,
127
128    TP_PROTO(const char *name, int branch),
129
130    TP_ARGS(name, branch),
131
132    TP_STRUCT__entry(
133        __array(char, name, 20)
134        __field(int, branch)
135    ),
136
137    TP_fast_assign(
138        strncpy(__entry->name, name, 20);
139        __entry->branch = branch;
140    ),
141
142    TP_printk("misc_event %s %d", __entry->name, __entry->branch)
143);
144
145
146#endif
147
148/***** NOTICE! The #if protection ends here. *****/
149
150
151/*
152 * There are several ways I could have done this. If I left out the
153 * TRACE_INCLUDE_PATH, then it would default to the kernel source
154 * include/trace/events directory.
155 *
156 * I could specify a path from the define_trace.h file back to this
157 * file.
158 *
159 * #define TRACE_INCLUDE_PATH ../../samples/trace_events
160 *
161 * But the safest and easiest way to simply make it use the directory
162 * that the file is in is to add in the Makefile:
163 *
164 * CFLAGS_trace-events-sample.o := -I$(src)
165 *
166 * This will make sure the current path is part of the include
167 * structure for our file so that define_trace.h can find it.
168 *
169 * I could have made only the top level directory the include:
170 *
171 * CFLAGS_trace-events-sample.o := -I$(PWD)
172 *
173 * And then let the path to this directory be the TRACE_INCLUDE_PATH:
174 *
175 * #define TRACE_INCLUDE_PATH samples/trace_events
176 *
177 * But then if something defines "samples" or "trace_events" as a macro
178 * then we could risk that being converted too, and give us an unexpected
179 * result.
180 */
181#undef TRACE_INCLUDE_PATH
182#undef TRACE_INCLUDE_FILE
183#define TRACE_INCLUDE_PATH .
184/*
185 * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal
186 */
187#define TRACE_INCLUDE_FILE sep_trace_events
188#include <trace/define_trace.h>
189

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