include/linux/dynamic_debug.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _DYNAMIC_DEBUG_H
   3 #define _DYNAMIC_DEBUG_H
   4
   5 #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
   6 #include <linux/jump_label.h>
   7 #endif
   8
   9 /*
  10  * An instance of this structure is created in a special
  11  * ELF section at every dynamic debug callsite.  At runtime,
  12  * the special section is treated as an array of these.
  13  */
  14 struct _ddebug {
  15         /*
  16          * These fields are used to drive the user interface
  17          * for selecting and displaying debug callsites.
  18          */
  19         const char *modname;
  20         const char *function;
  21         const char *filename;
  22         const char *format;
  23         unsigned int lineno:18;
  24         /*
  25          * The flags field controls the behaviour at the callsite.
  26          * The bits here are changed dynamically when the user
  27          * writes commands to <debugfs>/dynamic_debug/control
  28          */
  29 #define _DPRINTK_FLAGS_NONE     0
  30 #define _DPRINTK_FLAGS_PRINT    (1<<0) /* printk() a message using the format */
  31 #define _DPRINTK_FLAGS_INCL_MODNAME     (1<<1)
  32 #define _DPRINTK_FLAGS_INCL_FUNCNAME    (1<<2)
  33 #define _DPRINTK_FLAGS_INCL_LINENO      (1<<3)
  34 #define _DPRINTK_FLAGS_INCL_TID         (1<<4)
  35 #if defined DEBUG
  36 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
  37 #else
  38 #define _DPRINTK_FLAGS_DEFAULT 0
  39 #endif
  40         unsigned int flags:8;
  41 #ifdef HAVE_JUMP_LABEL
  42         union {
  43                 struct static_key_true dd_key_true;
  44                 struct static_key_false dd_key_false;
  45         } key;
  46 #endif
  47 } __attribute__((aligned(8)));
  48
  49
  50 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  51                                 const char *modname);
  52
  53 #if defined(CONFIG_DYNAMIC_DEBUG)
  54 extern int ddebug_remove_module(const char *mod_name);
  55 extern __printf(2, 3)
  56 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
  57
  58 extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
  59                                         const char *modname);
  60
  61 struct device;
  62
  63 extern __printf(3, 4)
  64 void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
  65                        const char *fmt, ...);
  66
  67 struct net_device;
  68
  69 extern __printf(3, 4)
  70 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
  71                           const struct net_device *dev,
  72                           const char *fmt, ...);
  73
  74 #define DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, key, init) \
  75         static struct _ddebug  __aligned(8)                     \
  76         __attribute__((section("__verbose"))) name = {          \
  77                 .modname = KBUILD_MODNAME,                      \
  78                 .function = __func__,                           \
  79                 .filename = __FILE__,                           \
  80                 .format = (fmt),                                \
  81                 .lineno = __LINE__,                             \
  82                 .flags = _DPRINTK_FLAGS_DEFAULT,                \
  83                 dd_key_init(key, init)                          \
  84         }
  85
  86 #ifdef HAVE_JUMP_LABEL
  87
  88 #define dd_key_init(key, init) key = (init)
  89
  90 #ifdef DEBUG
  91 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
  92         DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, .key.dd_key_true, \
  93                                           (STATIC_KEY_TRUE_INIT))
  94
  95 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
  96         static_branch_likely(&descriptor.key.dd_key_true)
  97 #else
  98 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
  99         DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, .key.dd_key_false, \
 100                                           (STATIC_KEY_FALSE_INIT))
 101
 102 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 103         static_branch_unlikely(&descriptor.key.dd_key_false)
 104 #endif
 105
 106 #else
 107
 108 #define dd_key_init(key, init)
 109
 110 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \
 111         DEFINE_DYNAMIC_DEBUG_METADATA_KEY(name, fmt, 0, 0)
 112
 113 #ifdef DEBUG
 114 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 115         likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 116 #else
 117 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 118         unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 119 #endif
 120
 121 #endif
 122
 123 #define dynamic_pr_debug(fmt, ...)                              \
 124 do {                                                            \
 125         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);         \
 126         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 127                 __dynamic_pr_debug(&descriptor, pr_fmt(fmt),    \
 128                                    ##__VA_ARGS__);              \
 129 } while (0)
 130
 131 #define dynamic_dev_dbg(dev, fmt, ...)                          \
 132 do {                                                            \
 133         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);         \
 134         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 135                 __dynamic_dev_dbg(&descriptor, dev, fmt,        \
 136                                   ##__VA_ARGS__);               \
 137 } while (0)
 138
 139 #define dynamic_netdev_dbg(dev, fmt, ...)                       \
 140 do {                                                            \
 141         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);         \
 142         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 143                 __dynamic_netdev_dbg(&descriptor, dev, fmt,     \
 144                                      ##__VA_ARGS__);            \
 145 } while (0)
 146
 147 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,      \
 148                          groupsize, buf, len, ascii)            \
 149 do {                                                            \
 150         DEFINE_DYNAMIC_DEBUG_METADATA(descriptor,               \
 151                 __builtin_constant_p(prefix_str) ? prefix_str : "hexdump");\
 152         if (DYNAMIC_DEBUG_BRANCH(descriptor))                   \
 153                 print_hex_dump(KERN_DEBUG, prefix_str,          \
 154                                prefix_type, rowsize, groupsize, \
 155                                buf, len, ascii);                \
 156 } while (0)
 157
 158 #else
 159
 160 #include <linux/string.h>
 161 #include <linux/errno.h>
 162
 163 static inline int ddebug_remove_module(const char *mod)
 164 {
 165         return 0;
 166 }
 167
 168 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 169                                                 const char *modname)
 170 {
 171         if (strstr(param, "dyndbg")) {
 172                 /* avoid pr_warn(), which wants pr_fmt() fully defined */
 173                 printk(KERN_WARNING "dyndbg param is supported only in "
 174                         "CONFIG_DYNAMIC_DEBUG builds\n");
 175                 return 0; /* allow and ignore */
 176         }
 177         return -EINVAL;
 178 }
 179
 180 #define dynamic_pr_debug(fmt, ...)                                      \
 181         do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
 182 #define dynamic_dev_dbg(dev, fmt, ...)                                  \
 183         do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
 184 #endif
 185
 186 #endif