LXR linux/include/linux/marker.h

   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 <linux/types.h>
  16
  17struct module;
  18struct marker;
  19
  20/**
  21 * marker_probe_func - Type of a marker probe function
  22 * @mdata: pointer of type struct marker
  23 * @private_data: caller site private data
  24 * @fmt: format string
  25 * @...: variable argument list
  26 *
  27 * Type of marker probe functions. They receive the mdata and need to parse the
  28 * format string to recover the variable argument list.
  29 */
  30typedef void marker_probe_func(const struct marker *mdata,
  31        void *private_data, const char *fmt, ...);
  32
  33struct marker {
  34        const char *name;       /* Marker name */
  35        const char *format;     /* Marker format string, describing the
  36                                 * variable argument list.
  37                                 */
  38        char state;             /* Marker state. */
  39        marker_probe_func *call;/* Probe handler function pointer */
  40        void *private;          /* Private probe data */
  41} __attribute__((aligned(8)));
  42
  43#ifdef CONFIG_MARKERS
  44
  45/*
  46 * Note : the empty asm volatile with read constraint is used here instead of a
  47 * "used" attribute to fix a gcc 4.1.x bug.
  48 * Make sure the alignment of the structure in the __markers section will
  49 * not add unwanted padding between the beginning of the section and the
  50 * structure. Force alignment to the same alignment as the section start.
  51 */
  52#define __trace_mark(name, call_data, format, args...)                  \
  53        do {                                                            \
  54                static const char __mstrtab_name_##name[]               \
  55                __attribute__((section("__markers_strings")))           \
  56                = #name;                                                \
  57                static const char __mstrtab_format_##name[]             \
  58                __attribute__((section("__markers_strings")))           \
  59                = format;                                               \
  60                static struct marker __mark_##name                      \
  61                __attribute__((section("__markers"), aligned(8))) =     \
  62                { __mstrtab_name_##name, __mstrtab_format_##name,       \
  63                0, __mark_empty_function, NULL };                       \
  64                __mark_check_format(format, ## args);                   \
  65                if (unlikely(__mark_##name.state)) {                    \
  66                        preempt_disable();                              \
  67                        (*__mark_##name.call)                           \
  68                                (&__mark_##name, call_data,             \
  69                                format, ## args);                       \
  70                        preempt_enable();                               \
  71                }                                                       \
  72        } while (0)
  73
  74extern void marker_update_probe_range(struct marker *begin,
  75        struct marker *end, struct module *probe_module, int *refcount);
  76#else /* !CONFIG_MARKERS */
  77#define __trace_mark(name, call_data, format, args...) \
  78                __mark_check_format(format, ## args)
  79static inline void marker_update_probe_range(struct marker *begin,
  80        struct marker *end, struct module *probe_module, int *refcount)
  81{ }
  82#endif /* CONFIG_MARKERS */
  83
  84/**
  85 * trace_mark - Marker
  86 * @name: marker name, not quoted.
  87 * @format: format string
  88 * @args...: variable argument list
  89 *
  90 * Places a marker.
  91 */
  92#define trace_mark(name, format, args...) \
  93        __trace_mark(name, NULL, format, ## args)
  94
  95#define MARK_MAX_FORMAT_LEN     1024
  96
  97/**
  98 * MARK_NOARGS - Format string for a marker with no argument.
  99 */
 100#define MARK_NOARGS " "
 101
 102/* To be used for string format validity checking with gcc */
 103static inline void __printf(1, 2) __mark_check_format(const char *fmt, ...)
 104{
 105}
 106
 107extern marker_probe_func __mark_empty_function;
 108
 109/*
 110 * Connect a probe to a marker.
 111 * private data pointer must be a valid allocated memory address, or NULL.
 112 */
 113extern int marker_probe_register(const char *name, const char *format,
 114                                marker_probe_func *probe, void *private);
 115
 116/*
 117 * Returns the private data given to marker_probe_register.
 118 */
 119extern void *marker_probe_unregister(const char *name);
 120/*
 121 * Unregister a marker by providing the registered private data.
 122 */
 123extern void *marker_probe_unregister_private_data(void *private);
 124
 125extern int marker_arm(const char *name);
 126extern int marker_disarm(const char *name);
 127extern void *marker_get_private_data(const char *name);
 128
 129#endif
 130