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  */
  88 TRACE_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
 107 TRACE_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
 126 TRACE_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>