Linux Kernel  3.7.1
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sep_trace_events.h
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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  */
88 TRACE_EVENT(sep_func_start,
89 
90  TP_PROTO(const char *name, int branch),
91 
92  TP_ARGS(name, branch),
93 
95  __array(char, name, 20)
96  __field(int, branch)
97  ),
98 
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 
107 TRACE_EVENT(sep_func_end,
108 
109  TP_PROTO(const char *name, int branch),
110 
111  TP_ARGS(name, branch),
112 
114  __array(char, name, 20)
115  __field(int, branch)
116  ),
117 
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 
126 TRACE_EVENT(sep_misc_event,
127 
128  TP_PROTO(const char *name, int branch),
129 
130  TP_ARGS(name, branch),
131 
133  __array(char, name, 20)
134  __field(int, branch)
135  ),
136 
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>