include/linux/dynamic_debug.h

   1 #ifndef _DYNAMIC_DEBUG_H
   2 #define _DYNAMIC_DEBUG_H
   3
   4 #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
   5 #include <linux/jump_label.h>
   6 #endif
   7
   8 /*
   9  * An instance of this structure is created in a special
  10  * ELF section at every dynamic debug callsite.  At runtime,
  11  * the special section is treated as an array of these.
  12  */
  13 struct _ddebug {
  14         /*
  15          * These fields are used to drive the user interface
  16          * for selecting and displaying debug callsites.
  17          */
  18         const char *modname;
  19         const char *function;
  20         const char *filename;
  21         const char *format;
  22         unsigned int lineno:18;
  23         /*
  24          * The flags field controls the behaviour at the callsite.
  25          * The bits here are changed dynamically when the user
  26          * writes commands to <debugfs>/dynamic_debug/control
  27          */
  28 #define _DPRINTK_FLAGS_NONE     0
  29 #define _DPRINTK_FLAGS_PRINT    (1<<0) /* printk() a message using the format */
  30 #define _DPRINTK_FLAGS_INCL_MODNAME     (1<<1)
  31 #define _DPRINTK_FLAGS_INCL_FUNCNAME    (1<<2)
  32 #define _DPRINTK_FLAGS_INCL_LINENO      (1<<3)
  33 #define _DPRINTK_FLAGS_INCL_TID         (1<<4)
  34 #if defined DEBUG
  35 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
  36 #else
  37 #define _DPRINTK_FLAGS_DEFAULT 0
  38 #endif
  39         unsigned int flags:8;
  40 #ifdef HAVE_JUMP_LABEL
  41         union {
  42                 struct static_key_true dd_key_true;
  43                 struct static_key_false dd_key_false;
  44         } key;
  45 #endif
  46 } __attribute__((aligned(8)));
  47
  48
  49 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  50                                 const char *modname);
  51
  52 #if defined(CONFIG_DYNAMIC_DEBUG)
  53 extern int ddebug_remove_module(const char *mod_name);
  54 extern __printf(2, 3)
  55 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
  56
  57 extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
  58                                         const char *modname);
  59
  60 struct device;
  61
  62 extern __printf(3, 4)
  63 void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
  64                        const char *fmt, ...);
  65
  66 struct net_device;
  67
  68 extern __printf(3, 4)
  69 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
  70                           const struct net_device *dev,
  71                           const char *fmt, ...);
  72
  73 #define DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, key, init) \
  74         static struct _ddebug  __aligned(8)                     \
  75         __attribute__((section("__verbose"))) name = {          \
  76                 .modname = KBUILD_MODNAME,                      \
  77                 .function = __func__,                           \
  78                 .filename = __FILE__,                           \
  79                 .format = (fmt),                                \
  80                 .lineno = __LINE__,                             \
  81                 .flags = _DPRINTK_FLAGS_DEFAULT,                \
  82                 dd_key_init(key, init)                          \
  83         }
  84
  85 #ifdef HAVE_JUMP_LABEL
  86
  87 #define dd_key_init(key, init) key = (init)
  88
  89 #ifdef DEBUG
  90 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
  91         DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, .key.dd_key_true, \
  92                                           (STATIC_KEY_TRUE_INIT))
  93
  94 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
  95         static_branch_likely(&descriptor.key.dd_key_true)
  96 #else
  97 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
  98         DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, .key.dd_key_false, \
  99                                           (STATIC_KEY_FALSE_INIT))
 100
 101 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 102         static_branch_unlikely(&descriptor.key.dd_key_false)
 103 #endif
 104
 105 #else
 106
 107 #define dd_key_init(key, init)
 108
 109 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
 110         DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, 0, 0)
 111
 112 #ifdef DEBUG
 113 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 114         likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 115 #else
 116 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 117         unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 118 #endif
 119
 120 #endif
 121
 122 #define dynamic_pr_debug(fmt, ...)                              \
 123 do {                                                            \
 124         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);         \
 125         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 126                 __dynamic_pr_debug(&descriptor, pr_fmt(fmt),    \
 127                                    ##__VA_ARGS__);              \
 128 } while (0)
 129
 130 #define dynamic_dev_dbg(dev, fmt, ...)                          \
 131 do {                                                            \
 132         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);         \
 133         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 134                 __dynamic_dev_dbg(&descriptor, dev, fmt,        \
 135                                   ##__VA_ARGS__);               \
 136 } while (0)
 137
 138 #define dynamic_netdev_dbg(dev, fmt, ...)                       \
 139 do {                                                            \
 140         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);         \
 141         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 142                 __dynamic_netdev_dbg(&descriptor, dev, fmt,     \
 143                                      ##__VA_ARGS__);            \
 144 } while (0)
 145
 146 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,      \
 147                          groupsize, buf, len, ascii)            \
 148 do {                                                            \
 149         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor,               \
 150                 __builtin_constant_p(prefix_str) ? prefix_str : "hexdump");\
 151         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 152                 print_hex_dump(KERN_DEBUG, prefix_str,          \
 153                                prefix_type, rowsize, groupsize, \
 154                                buf, len, ascii);                \
 155 } while (0)
 156
 157 #else
 158
 159 #include <linux/string.h>
 160 #include <linux/errno.h>
 161
 162 static inline int ddebug_remove_module(const char *mod)
 163 {
 164         return 0;
 165 }
 166
 167 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 168                                                 const char *modname)
 169 {
 170         if (strstr(param, "dyndbg")) {
 171                 /* avoid pr_warn(), which wants pr_fmt() fully defined */
 172                 printk(KERN_WARNING "dyndbg param is supported only in "
 173                         "CONFIG_DYNAMIC_DEBUG builds\n");
 174                 return 0; /* allow and ignore */
 175         }
 176         return -EINVAL;
 177 }
 178
 179 #define dynamic_pr_debug(fmt, ...)                                      \
 180         do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
 181 #define dynamic_dev_dbg(dev, fmt, ...)                                  \
 182         do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
 183 #endif
 184
 185 #endif