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                                /* Probe wrapper */
  48        void (*call)(const struct marker *mdata, void *call_private, ...);
  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 * The "generic" argument controls which marker enabling mechanism must be used.
  63 * If generic is true, a variable read is used.
  64 * If generic is false, immediate values are used.
  65 */
  66#define __trace_mark(generic, name, call_private, format, args...)      \
  67        do {                                                            \
  68                static const char __mstrtab_##name[]                    \
  69                __attribute__((section("__markers_strings")))           \
  70                = #name "\0" format;                                    \
  71                static struct marker __mark_##name                      \
  72                __attribute__((section("__markers"), aligned(8))) =     \
  73                { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)],   \
  74                0, 0, marker_probe_cb,                                  \
  75                { __mark_empty_function, NULL}, NULL };                 \
  76                __mark_check_format(format, ## args);                   \
  77                if (unlikely(__mark_##name.state)) {                    \
  78                        (*__mark_##name.call)                           \
  79                                (&__mark_##name, call_private, ## args);\
  80                }                                                       \
  81        } while (0)
  82
  83extern void marker_update_probe_range(struct marker *begin,
  84        struct marker *end);
  85#else /* !CONFIG_MARKERS */
  86#define __trace_mark(generic, name, call_private, format, args...) \
  87                __mark_check_format(format, ## args)
  88static inline void marker_update_probe_range(struct marker *begin,
  89        struct marker *end)
  90{ }
  91#endif /* CONFIG_MARKERS */
  92
  93/**
  94 * trace_mark - Marker using code patching
  95 * @name: marker name, not quoted.
  96 * @format: format string
  97 * @args...: variable argument list
  98 *
  99 * Places a marker using optimized code patching technique (imv_read())
 100 * to be enabled when immediate values are present.
 101 */
 102#define trace_mark(name, format, args...) \
 103        __trace_mark(0, name, NULL, format, ## args)
 104
 105/**
 106 * _trace_mark - Marker using variable read
 107 * @name: marker name, not quoted.
 108 * @format: format string
 109 * @args...: variable argument list
 110 *
 111 * Places a marker using a standard memory read (_imv_read()) to be
 112 * enabled. Should be used for markers in code paths where instruction
 113 * modification based enabling is not welcome. (__init and __exit functions,
 114 * lockdep, some traps, printk).
 115 */
 116#define _trace_mark(name, format, args...) \
 117        __trace_mark(1, name, NULL, format, ## args)
 118
 119/**
 120 * MARK_NOARGS - Format string for a marker with no argument.
 121 */
 122#define MARK_NOARGS " "
 123
 124/* To be used for string format validity checking with gcc */
 125static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
 126{
 127}
 128
 129#define __mark_check_format(format, args...)                            \
 130        do {                                                            \
 131                if (0)                                                  \
 132                        ___mark_check_format(format, ## args);          \
 133        } while (0)
 134
 135extern marker_probe_func __mark_empty_function;
 136
 137extern void marker_probe_cb(const struct marker *mdata,
 138        void *call_private, ...);
 139extern void marker_probe_cb_noarg(const struct marker *mdata,
 140        void *call_private, ...);
 141
 142/*
 143 * Connect a probe to a marker.
 144 * private data pointer must be a valid allocated memory address, or NULL.
 145 */
 146extern int marker_probe_register(const char *name, const char *format,
 147                                marker_probe_func *probe, void *probe_private);
 148
 149/*
 150 * Returns the private data given to marker_probe_register.
 151 */
 152extern int marker_probe_unregister(const char *name,
 153        marker_probe_func *probe, void *probe_private);
 154/*
 155 * Unregister a marker by providing the registered private data.
 156 */
 157extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 158        void *probe_private);
 159
 160extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
 161        int num);
 162
 163#endif
 164