include/linux/dynamic_debug.h

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