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
  17 struct module;
  18 struct 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  */
  32 typedef void marker_probe_func(void *probe_private, void *call_private,
  33                 const char *fmt, va_list *args);
  34
  35 struct marker_probe_closure {
  36         marker_probe_func *func;        /* Callback */
  37         void *probe_private;            /* Private probe data */
  38 };
  39
  40 struct 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
  80 extern 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)
  85 static 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 */
 107 static 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
 117 extern marker_probe_func __mark_empty_function;
 118
 119 extern void marker_probe_cb(const struct marker *mdata,
 120         void *call_private, const char *fmt, ...);
 121 extern 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  */
 128 extern 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  */
 134 extern 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  */
 139 extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 140         void *probe_private);
 141
 142 extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
 143         int num);
 144
 145 #endif