LXR linux/include/linux/dynamic

   1#ifndef _DYNAMIC_DEBUG_H
   2#define _DYNAMIC_DEBUG_H
   3
   4/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
   5 * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
   6 * use independent hash functions, to reduce the chance of false positives.
   7 */
   8extern long long dynamic_debug_enabled;
   9extern long long dynamic_debug_enabled2;
  10
  11/*
  12 * An instance of this structure is created in a special
  13 * ELF section at every dynamic debug callsite.  At runtime,
  14 * the special section is treated as an array of these.
  15 */
  16struct _ddebug {
  17        /*
  18         * These fields are used to drive the user interface
  19         * for selecting and displaying debug callsites.
  20         */
  21        const char *modname;
  22        const char *function;
  23        const char *filename;
  24        const char *format;
  25        char primary_hash;
  26        char secondary_hash;
  27        unsigned int lineno:24;
  28        /*
  29         * The flags field controls the behaviour at the callsite.
  30         * The bits here are changed dynamically when the user
  31         * writes commands to <debugfs>/dynamic_debug/ddebug
  32         */
  33#define _DPRINTK_FLAGS_PRINT   (1<<0)  /* printk() a message using the format */
  34#define _DPRINTK_FLAGS_DEFAULT 0
  35        unsigned int flags:8;
  36} __attribute__((aligned(8)));
  37
  38
  39int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  40                                const char *modname);
  41
  42#if defined(CONFIG_DYNAMIC_DEBUG)
  43extern int ddebug_remove_module(char *mod_name);
  44
  45#define __dynamic_dbg_enabled(dd)  ({        \
  46        int __ret = 0;                                                       \
  47        if (unlikely((dynamic_debug_enabled & (1LL << DEBUG_HASH)) &&        \
  48                        (dynamic_debug_enabled2 & (1LL << DEBUG_HASH2))))   \
  49                                if (unlikely(dd.flags))                      \
  50                                        __ret = 1;                           \
  51        __ret; })
  52
  53#define dynamic_pr_debug(fmt, ...) do {                                 \
  54        static struct _ddebug descriptor                                \
  55        __used                                                          \
  56        __attribute__((section("__verbose"), aligned(8))) =             \
  57        { KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH,  \
  58                DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT };        \
  59        if (__dynamic_dbg_enabled(descriptor))                          \
  60                printk(KERN_DEBUG KBUILD_MODNAME ":" pr_fmt(fmt),       \
  61                                ##__VA_ARGS__);                         \
  62        } while (0)
  63
  64
  65#define dynamic_dev_dbg(dev, fmt, ...) do {                             \
  66        static struct _ddebug descriptor                                \
  67        __used                                                          \
  68        __attribute__((section("__verbose"), aligned(8))) =             \
  69        { KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH,  \
  70                DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT };        \
  71        if (__dynamic_dbg_enabled(descriptor))                          \
  72                        dev_printk(KERN_DEBUG, dev,                     \
  73                                        KBUILD_MODNAME ": " fmt,        \
  74                                        ##__VA_ARGS__);                 \
  75        } while (0)
  76
  77#else
  78
  79static inline int ddebug_remove_module(char *mod)
  80{
  81        return 0;
  82}
  83
  84#define dynamic_pr_debug(fmt, ...)  do { } while (0)
  85#define dynamic_dev_dbg(dev, format, ...)  do { } while (0)
  86#endif
  87
  88#endif
  89