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(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 CONFIG_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
  51 #if defined(CONFIG_DYNAMIC_DEBUG)
  52 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  53                                 const char *modname);
  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 struct ib_device;
  75
  76 extern __printf(3, 4)
  77 void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  78                          const struct ib_device *ibdev,
  79                          const char *fmt, ...);
  80
  81 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)                \
  82         static struct _ddebug  __aligned(8)                     \
  83         __attribute__((section("__verbose"))) name = {          \
  84                 .modname = KBUILD_MODNAME,                      \
  85                 .function = __func__,                           \
  86                 .filename = __FILE__,                           \
  87                 .format = (fmt),                                \
  88                 .lineno = __LINE__,                             \
  89                 .flags = _DPRINTK_FLAGS_DEFAULT,                \
  90                 _DPRINTK_KEY_INIT                               \
  91         }
  92
  93 #ifdef CONFIG_JUMP_LABEL
  94
  95 #ifdef DEBUG
  96
  97 #define _DPRINTK_KEY_INIT .key.dd_key_true = (STATIC_KEY_TRUE_INIT)
  98
  99 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 100         static_branch_likely(&descriptor.key.dd_key_true)
 101 #else
 102 #define _DPRINTK_KEY_INIT .key.dd_key_false = (STATIC_KEY_FALSE_INIT)
 103
 104 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 105         static_branch_unlikely(&descriptor.key.dd_key_false)
 106 #endif
 107
 108 #else /* !HAVE_JUMP_LABEL */
 109
 110 #define _DPRINTK_KEY_INIT
 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_func_call(id, fmt, func, ...) do {    \
 123         DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);         \
 124         if (DYNAMIC_DEBUG_BRANCH(id))                   \
 125                 func(&id, ##__VA_ARGS__);               \
 126 } while (0)
 127
 128 #define __dynamic_func_call_no_desc(id, fmt, func, ...) do {    \
 129         DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);                 \
 130         if (DYNAMIC_DEBUG_BRANCH(id))                           \
 131                 func(__VA_ARGS__);                              \
 132 } while (0)
 133
 134 /*
 135  * "Factory macro" for generating a call to func, guarded by a
 136  * DYNAMIC_DEBUG_BRANCH. The dynamic debug decriptor will be
 137  * initialized using the fmt argument. The function will be called with
 138  * the address of the descriptor as first argument, followed by all
 139  * the varargs. Note that fmt is repeated in invocations of this
 140  * macro.
 141  */
 142 #define _dynamic_func_call(fmt, func, ...)                              \
 143         __dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
 144 /*
 145  * A variant that does the same, except that the descriptor is not
 146  * passed as the first argument to the function; it is only called
 147  * with precisely the macro's varargs.
 148  */
 149 #define _dynamic_func_call_no_desc(fmt, func, ...)      \
 150         __dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
 151
 152 #define dynamic_pr_debug(fmt, ...)                              \
 153         _dynamic_func_call(fmt, __dynamic_pr_debug,             \
 154                            pr_fmt(fmt), ##__VA_ARGS__)
 155
 156 #define dynamic_dev_dbg(dev, fmt, ...)                          \
 157         _dynamic_func_call(fmt,__dynamic_dev_dbg,               \
 158                            dev, fmt, ##__VA_ARGS__)
 159
 160 #define dynamic_netdev_dbg(dev, fmt, ...)                       \
 161         _dynamic_func_call(fmt, __dynamic_netdev_dbg,           \
 162                            dev, fmt, ##__VA_ARGS__)
 163
 164 #define dynamic_ibdev_dbg(dev, fmt, ...)                        \
 165         _dynamic_func_call(fmt, __dynamic_ibdev_dbg,            \
 166                            dev, fmt, ##__VA_ARGS__)
 167
 168 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,              \
 169                          groupsize, buf, len, ascii)                    \
 170         _dynamic_func_call_no_desc(__builtin_constant_p(prefix_str) ? prefix_str : "hexdump", \
 171                                    print_hex_dump,                      \
 172                                    KERN_DEBUG, prefix_str, prefix_type, \
 173                                    rowsize, groupsize, buf, len, ascii)
 174
 175 #else
 176
 177 #include <linux/string.h>
 178 #include <linux/errno.h>
 179
 180 static inline int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 181                                     const char *modname)
 182 {
 183         return 0;
 184 }
 185
 186 static inline int ddebug_remove_module(const char *mod)
 187 {
 188         return 0;
 189 }
 190
 191 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 192                                                 const char *modname)
 193 {
 194         if (strstr(param, "dyndbg")) {
 195                 /* avoid pr_warn(), which wants pr_fmt() fully defined */
 196                 printk(KERN_WARNING "dyndbg param is supported only in "
 197                         "CONFIG_DYNAMIC_DEBUG builds\n");
 198                 return 0; /* allow and ignore */
 199         }
 200         return -EINVAL;
 201 }
 202
 203 #define dynamic_pr_debug(fmt, ...)                                      \
 204         do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
 205 #define dynamic_dev_dbg(dev, fmt, ...)                                  \
 206         do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
 207 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,              \
 208                          groupsize, buf, len, ascii)                    \
 209         do { if (0)                                                     \
 210                 print_hex_dump(KERN_DEBUG, prefix_str, prefix_type,     \
 211                                 rowsize, groupsize, buf, len, ascii);   \
 212         } while (0)
 213 #endif
 214
 215 #endif