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 * @probe_private: probe private data
  23 * @call_private: call site private data
  24 * @fmt: format string
  25 * @args: variable argument list pointer. Use a pointer to overcome C's
  26 *        inability to pass this around as a pointer in a portable manner in
  27 *        the callee otherwise.
  28 *
  29 * Type of marker probe functions. They receive the mdata and need to parse the
  30 * format string to recover the variable argument list.
  31 */
  32typedef void marker_probe_func(void *probe_private, void *call_private,
  33                const char *fmt, va_list *args);
  34
  35struct marker_probe_closure {
  36        marker_probe_func *func;        /* Callback */
  37        void *probe_private;            /* Private probe data */
  38};
  39
  40struct marker {
  41        const char *name;       /* Marker name */
  42        const char *format;     /* Marker format string, describing the
  43                                 * variable argument list.
  44                                 */
  45        char state;             /* Marker state. */
  46        char ptype;             /* probe type : 0 : single, 1 : multi */
  47        void (*call)(const struct marker *mdata,        /* Probe wrapper */
  48                void *call_private, const char *fmt, ...);
  49        struct marker_probe_closure single;
  50        struct marker_probe_closure *multi;
  51} __attribute__((aligned(8)));
  52
  53#ifdef CONFIG_MARKERS
  54
  55/*
  56 * Note : the empty asm volatile with read constraint is used here instead of a
  57 * "used" attribute to fix a gcc 4.1.x bug.
  58 * Make sure the alignment of the structure in the __markers section will
  59 * not add unwanted padding between the beginning of the section and the
  60 * structure. Force alignment to the same alignment as the section start.
  61 */
  62#define __trace_mark(name, call_private, format, args...)               \
  63        do {                                                            \
  64                static const char __mstrtab_##name[]                    \
  65                __attribute__((section("__markers_strings")))           \
  66                = #name "\0" format;                                    \
  67                static struct marker __mark_##name                      \
  68                __attribute__((section("__markers"), aligned(8))) =     \
  69                { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)],   \
  70                0, 0, marker_probe_cb,                                  \
  71                { __mark_empty_function, NULL}, NULL };                 \
  72                __mark_check_format(format, ## args);                   \
  73                if (unlikely(__mark_##name.state)) {                    \
  74                        (*__mark_##name.call)                           \
  75                                (&__mark_##name, call_private,          \
  76                                format, ## args);                       \
  77                }                                                       \
  78        } while (0)
  79
  80extern void marker_update_probe_range(struct marker *begin,
  81        struct marker *end);
  82#else /* !CONFIG_MARKERS */
  83#define __trace_mark(name, call_private, format, args...) \
  84                __mark_check_format(format, ## args)
  85static inline void marker_update_probe_range(struct marker *begin,
  86        struct marker *end)
  87{ }
  88#endif /* CONFIG_MARKERS */
  89
  90/**
  91 * trace_mark - Marker
  92 * @name: marker name, not quoted.
  93 * @format: format string
  94 * @args...: variable argument list
  95 *
  96 * Places a marker.
  97 */
  98#define trace_mark(name, format, args...) \
  99        __trace_mark(name, NULL, format, ## args)
 100
 101/**
 102 * MARK_NOARGS - Format string for a marker with no argument.
 103 */
 104#define MARK_NOARGS " "
 105
 106/* To be used for string format validity checking with gcc */
 107static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
 108{
 109}
 110
 111#define __mark_check_format(format, args...)                            \
 112        do {                                                            \
 113                if (0)                                                  \
 114                        ___mark_check_format(format, ## args);          \
 115        } while (0)
 116
 117extern marker_probe_func __mark_empty_function;
 118
 119extern void marker_probe_cb(const struct marker *mdata,
 120        void *call_private, const char *fmt, ...);
 121extern void marker_probe_cb_noarg(const struct marker *mdata,
 122        void *call_private, const char *fmt, ...);
 123
 124/*
 125 * Connect a probe to a marker.
 126 * private data pointer must be a valid allocated memory address, or NULL.
 127 */
 128extern int marker_probe_register(const char *name, const char *format,
 129                                marker_probe_func *probe, void *probe_private);
 130
 131/*
 132 * Returns the private data given to marker_probe_register.
 133 */
 134extern int marker_probe_unregister(const char *name,
 135        marker_probe_func *probe, void *probe_private);
 136/*
 137 * Unregister a marker by providing the registered private data.
 138 */
 139extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 140        void *probe_private);
 141
 142extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
 143        int num);
 144
 145#endif
 146