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
  36 #define _DPRINTK_FLAGS_INCL_ANY         \
  37         (_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
  38          _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID)
  39
  40 #if defined DEBUG
  41 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
  42 #else
  43 #define _DPRINTK_FLAGS_DEFAULT 0
  44 #endif
  45         unsigned int flags:8;
  46 #ifdef CONFIG_JUMP_LABEL
  47         union {
  48                 struct static_key_true dd_key_true;
  49                 struct static_key_false dd_key_false;
  50         } key;
  51 #endif
  52 } __attribute__((aligned(8)));
  53
  54
  55
  56 #if defined(CONFIG_DYNAMIC_DEBUG_CORE)
  57
  58 /* exported for module authors to exercise >control */
  59 int dynamic_debug_exec_queries(const char *query, const char *modname);
  60
  61 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  62                                 const char *modname);
  63 extern int ddebug_remove_module(const char *mod_name);
  64 extern __printf(2, 3)
  65 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
  66
  67 extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
  68                                         const char *modname);
  69
  70 struct device;
  71
  72 extern __printf(3, 4)
  73 void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
  74                        const char *fmt, ...);
  75
  76 struct net_device;
  77
  78 extern __printf(3, 4)
  79 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
  80                           const struct net_device *dev,
  81                           const char *fmt, ...);
  82
  83 struct ib_device;
  84
  85 extern __printf(3, 4)
  86 void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  87                          const struct ib_device *ibdev,
  88                          const char *fmt, ...);
  89
  90 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)                \
  91         static struct _ddebug  __aligned(8)                     \
  92         __section("__dyndbg") name = {                          \
  93                 .modname = KBUILD_MODNAME,                      \
  94                 .function = __func__,                           \
  95                 .filename = __FILE__,                           \
  96                 .format = (fmt),                                \
  97                 .lineno = __LINE__,                             \
  98                 .flags = _DPRINTK_FLAGS_DEFAULT,                \
  99                 _DPRINTK_KEY_INIT                               \
 100         }
 101
 102 #ifdef CONFIG_JUMP_LABEL
 103
 104 #ifdef DEBUG
 105
 106 #define _DPRINTK_KEY_INIT .key.dd_key_true = (STATIC_KEY_TRUE_INIT)
 107
 108 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 109         static_branch_likely(&descriptor.key.dd_key_true)
 110 #else
 111 #define _DPRINTK_KEY_INIT .key.dd_key_false = (STATIC_KEY_FALSE_INIT)
 112
 113 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 114         static_branch_unlikely(&descriptor.key.dd_key_false)
 115 #endif
 116
 117 #else /* !CONFIG_JUMP_LABEL */
 118
 119 #define _DPRINTK_KEY_INIT
 120
 121 #ifdef DEBUG
 122 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 123         likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 124 #else
 125 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 126         unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 127 #endif
 128
 129 #endif /* CONFIG_JUMP_LABEL */
 130
 131 #define __dynamic_func_call(id, fmt, func, ...) do {    \
 132         DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);         \
 133         if (DYNAMIC_DEBUG_BRANCH(id))                   \
 134                 func(&id, ##__VA_ARGS__);               \
 135 } while (0)
 136
 137 #define __dynamic_func_call_no_desc(id, fmt, func, ...) do {    \
 138         DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);                 \
 139         if (DYNAMIC_DEBUG_BRANCH(id))                           \
 140                 func(__VA_ARGS__);                              \
 141 } while (0)
 142
 143 /*
 144  * "Factory macro" for generating a call to func, guarded by a
 145  * DYNAMIC_DEBUG_BRANCH. The dynamic debug descriptor will be
 146  * initialized using the fmt argument. The function will be called with
 147  * the address of the descriptor as first argument, followed by all
 148  * the varargs. Note that fmt is repeated in invocations of this
 149  * macro.
 150  */
 151 #define _dynamic_func_call(fmt, func, ...)                              \
 152         __dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
 153 /*
 154  * A variant that does the same, except that the descriptor is not
 155  * passed as the first argument to the function; it is only called
 156  * with precisely the macro's varargs.
 157  */
 158 #define _dynamic_func_call_no_desc(fmt, func, ...)      \
 159         __dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
 160
 161 #define dynamic_pr_debug(fmt, ...)                              \
 162         _dynamic_func_call(fmt, __dynamic_pr_debug,             \
 163                            pr_fmt(fmt), ##__VA_ARGS__)
 164
 165 #define dynamic_dev_dbg(dev, fmt, ...)                          \
 166         _dynamic_func_call(fmt,__dynamic_dev_dbg,               \
 167                            dev, fmt, ##__VA_ARGS__)
 168
 169 #define dynamic_netdev_dbg(dev, fmt, ...)                       \
 170         _dynamic_func_call(fmt, __dynamic_netdev_dbg,           \
 171                            dev, fmt, ##__VA_ARGS__)
 172
 173 #define dynamic_ibdev_dbg(dev, fmt, ...)                        \
 174         _dynamic_func_call(fmt, __dynamic_ibdev_dbg,            \
 175                            dev, fmt, ##__VA_ARGS__)
 176
 177 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,              \
 178                          groupsize, buf, len, ascii)                    \
 179         _dynamic_func_call_no_desc(__builtin_constant_p(prefix_str) ? prefix_str : "hexdump", \
 180                                    print_hex_dump,                      \
 181                                    KERN_DEBUG, prefix_str, prefix_type, \
 182                                    rowsize, groupsize, buf, len, ascii)
 183
 184 #else /* !CONFIG_DYNAMIC_DEBUG_CORE */
 185
 186 #include <linux/string.h>
 187 #include <linux/errno.h>
 188 #include <linux/printk.h>
 189
 190 static inline int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 191                                     const char *modname)
 192 {
 193         return 0;
 194 }
 195
 196 static inline int ddebug_remove_module(const char *mod)
 197 {
 198         return 0;
 199 }
 200
 201 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 202                                                 const char *modname)
 203 {
 204         if (strstr(param, "dyndbg")) {
 205                 /* avoid pr_warn(), which wants pr_fmt() fully defined */
 206                 printk(KERN_WARNING "dyndbg param is supported only in "
 207                         "CONFIG_DYNAMIC_DEBUG builds\n");
 208                 return 0; /* allow and ignore */
 209         }
 210         return -EINVAL;
 211 }
 212
 213 #define dynamic_pr_debug(fmt, ...)                                      \
 214         do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
 215 #define dynamic_dev_dbg(dev, fmt, ...)                                  \
 216         do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
 217 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,              \
 218                          groupsize, buf, len, ascii)                    \
 219         do { if (0)                                                     \
 220                 print_hex_dump(KERN_DEBUG, prefix_str, prefix_type,     \
 221                                 rowsize, groupsize, buf, len, ascii);   \
 222         } while (0)
 223
 224 static inline int dynamic_debug_exec_queries(const char *query, const char *modname)
 225 {
 226         pr_warn("kernel not built with CONFIG_DYNAMIC_DEBUG_CORE\n");
 227         return 0;
 228 }
 229
 230 #endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
 231
 232 #endif