LXR linux/samples/ftrace/sample-trace-array.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2
   3/*
   4 * If TRACE_SYSTEM is defined, that will be the directory created
   5 * in the ftrace directory under /sys/kernel/tracing/events/<system>
   6 *
   7 * The define_trace.h below will also look for a file name of
   8 * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
   9 * In this case, it would look for sample-trace.h
  10 *
  11 * If the header name will be different than the system name
  12 * (as in this case), then you can override the header name that
  13 * define_trace.h will look up by defining TRACE_INCLUDE_FILE
  14 *
  15 * This file is called sample-trace-array.h but we want the system
  16 * to be called "sample-subsystem". Therefore we must define the name of this
  17 * file:
  18 *
  19 * #define TRACE_INCLUDE_FILE sample-trace-array
  20 *
  21 * As we do in the bottom of this file.
  22 *
  23 * Notice that TRACE_SYSTEM should be defined outside of #if
  24 * protection, just like TRACE_INCLUDE_FILE.
  25 */
  26#undef TRACE_SYSTEM
  27#define TRACE_SYSTEM sample-subsystem
  28
  29/*
  30 * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric
  31 * and underscore), although it may start with numbers. If for some
  32 * reason it is not, you need to add the following lines:
  33 */
  34#undef TRACE_SYSTEM_VAR
  35#define TRACE_SYSTEM_VAR sample_subsystem
  36
  37/*
  38 * But the above is only needed if TRACE_SYSTEM is not alpha-numeric
  39 * and underscored. By default, TRACE_SYSTEM_VAR will be equal to
  40 * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if
  41 * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with
  42 * only alpha-numeric and underscores.
  43 *
  44 * The TRACE_SYSTEM_VAR is only used internally and not visible to
  45 * user space.
  46 */
  47
  48/*
  49 * Notice that this file is not protected like a normal header.
  50 * We also must allow for rereading of this file. The
  51 *
  52 *  || defined(TRACE_HEADER_MULTI_READ)
  53 *
  54 * serves this purpose.
  55 */
  56#if !defined(_SAMPLE_TRACE_ARRAY_H) || defined(TRACE_HEADER_MULTI_READ)
  57#define _SAMPLE_TRACE_ARRAY_H
  58
  59#include <linux/tracepoint.h>
  60TRACE_EVENT(sample_event,
  61
  62        TP_PROTO(int count, unsigned long time),
  63
  64        TP_ARGS(count, time),
  65
  66        TP_STRUCT__entry(
  67                __field(int, count)
  68                __field(unsigned long, time)
  69        ),
  70
  71        TP_fast_assign(
  72                __entry->count = count;
  73                __entry->time = time;
  74        ),
  75
  76        TP_printk("count value=%d at jiffies=%lu", __entry->count,
  77                __entry->time)
  78        );
  79#endif
  80
  81#undef TRACE_INCLUDE_PATH
  82#define TRACE_INCLUDE_PATH .
  83#define TRACE_INCLUDE_FILE sample-trace-array
  84#include <trace/define_trace.h>
  85