include/linux/dynamic_debug.h

   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  */
   8 extern long long dynamic_debug_enabled;
   9 extern 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  */
  16 struct _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         unsigned int lineno:24;
  26         /*
  27          * The flags field controls the behaviour at the callsite.
  28          * The bits here are changed dynamically when the user
  29          * writes commands to <debugfs>/dynamic_debug/control
  30          */
  31 #define _DPRINTK_FLAGS_PRINT   (1<<0)  /* printk() a message using the format */
  32 #define _DPRINTK_FLAGS_INCL_MODNAME     (1<<1)
  33 #define _DPRINTK_FLAGS_INCL_FUNCNAME    (1<<2)
  34 #define _DPRINTK_FLAGS_INCL_LINENO      (1<<3)
  35 #define _DPRINTK_FLAGS_INCL_TID         (1<<4)
  36 #define _DPRINTK_FLAGS_DEFAULT 0
  37         unsigned int flags:8;
  38         char enabled;
  39 } __attribute__((aligned(8)));
  40
  41
  42 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  43                                 const char *modname);
  44
  45 #if defined(CONFIG_DYNAMIC_DEBUG)
  46 extern int ddebug_remove_module(const char *mod_name);
  47 extern int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
  48         __attribute__ ((format (printf, 2, 3)));
  49
  50 #define dynamic_pr_debug(fmt, ...) do {                                 \
  51         static struct _ddebug descriptor                                \
  52         __used                                                          \
  53         __attribute__((section("__verbose"), aligned(8))) =             \
  54         { KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__,            \
  55                 _DPRINTK_FLAGS_DEFAULT };                               \
  56         if (unlikely(descriptor.enabled))                               \
  57                 __dynamic_pr_debug(&descriptor, pr_fmt(fmt), ##__VA_ARGS__); \
  58         } while (0)
  59
  60
  61 #define dynamic_dev_dbg(dev, fmt, ...) do {                             \
  62         static struct _ddebug descriptor                                \
  63         __used                                                          \
  64         __attribute__((section("__verbose"), aligned(8))) =             \
  65         { KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__,            \
  66                 _DPRINTK_FLAGS_DEFAULT };                               \
  67         if (unlikely(descriptor.enabled))                               \
  68                 dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__);        \
  69         } while (0)
  70
  71 #else
  72
  73 static inline int ddebug_remove_module(const char *mod)
  74 {
  75         return 0;
  76 }
  77
  78 #define dynamic_pr_debug(fmt, ...)                                      \
  79         do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
  80 #define dynamic_dev_dbg(dev, fmt, ...)                                  \
  81         do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
  82 #endif
  83
  84 #endif