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 #include <linux/build_bug.h>
  10
  11 /*
  12  * An instance of this structure is created in a special
  13  * ELF section at every dynamic debug callsite.  At runtime,
  14  * the special section is treated as an array of these.
  15  */
  16 struct _ddebug {
  17         /*
  18          * These fields are used to drive the user interface
  19          * for selecting and displaying debug callsites.
  20          */
  21         const char *modname;
  22         const char *function;
  23         const char *filename;
  24         const char *format;
  25         unsigned int lineno:18;
  26 #define CLS_BITS 6
  27         unsigned int class_id:CLS_BITS;
  28 #define _DPRINTK_CLASS_DFLT             ((1 << CLS_BITS) - 1)
  29         /*
  30          * The flags field controls the behaviour at the callsite.
  31          * The bits here are changed dynamically when the user
  32          * writes commands to <debugfs>/dynamic_debug/control
  33          */
  34 #define _DPRINTK_FLAGS_NONE     0
  35 #define _DPRINTK_FLAGS_PRINT    (1<<0) /* printk() a message using the format */
  36 #define _DPRINTK_FLAGS_INCL_MODNAME     (1<<1)
  37 #define _DPRINTK_FLAGS_INCL_FUNCNAME    (1<<2)
  38 #define _DPRINTK_FLAGS_INCL_LINENO      (1<<3)
  39 #define _DPRINTK_FLAGS_INCL_TID         (1<<4)
  40 #define _DPRINTK_FLAGS_INCL_SOURCENAME  (1<<5)
  41
  42 #define _DPRINTK_FLAGS_INCL_ANY         \
  43         (_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
  44          _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID |\
  45          _DPRINTK_FLAGS_INCL_SOURCENAME)
  46
  47 #if defined DEBUG
  48 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
  49 #else
  50 #define _DPRINTK_FLAGS_DEFAULT 0
  51 #endif
  52         unsigned int flags:8;
  53 #ifdef CONFIG_JUMP_LABEL
  54         union {
  55                 struct static_key_true dd_key_true;
  56                 struct static_key_false dd_key_false;
  57         } key;
  58 #endif
  59 } __attribute__((aligned(8)));
  60
  61 enum class_map_type {
  62         DD_CLASS_TYPE_DISJOINT_BITS,
  63         /**
  64          * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, one per bit.
  65          * expecting hex input. Built for drm.debug, basis for other types.
  66          */
  67         DD_CLASS_TYPE_LEVEL_NUM,
  68         /**
  69          * DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N.
  70          * N turns on just bits N-1 .. 0, so N=0 turns all bits off.
  71          */
  72         DD_CLASS_TYPE_DISJOINT_NAMES,
  73         /**
  74          * DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES,
  75          * classes are independent, like _DISJOINT_BITS.
  76          */
  77         DD_CLASS_TYPE_LEVEL_NAMES,
  78         /**
  79          * DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES,
  80          * intended for names like: INFO,DEBUG,TRACE, with a module prefix
  81          * avoid EMERG,ALERT,CRIT,ERR,WARNING: they're not debug
  82          */
  83 };
  84
  85 struct ddebug_class_map {
  86         struct list_head link;
  87         struct module *mod;
  88         const char *mod_name;   /* needed for builtins */
  89         const char **class_names;
  90         const int length;
  91         const int base;         /* index of 1st .class_id, allows split/shared space */
  92         enum class_map_type map_type;
  93 };
  94
  95 /**
  96  * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
  97  * @_var:   a struct ddebug_class_map, passed to module_param_cb
  98  * @_type:  enum class_map_type, chooses bits/verbose, numeric/symbolic
  99  * @_base:  offset of 1st class-name. splits .class_id space
 100  * @classes: class-names used to control class'd prdbgs
 101  */
 102 #define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)             \
 103         static const char *_var##_classnames[] = { __VA_ARGS__ };       \
 104         static struct ddebug_class_map __aligned(8) __used              \
 105                 __section("__dyndbg_classes") _var = {                  \
 106                 .mod = THIS_MODULE,                                     \
 107                 .mod_name = KBUILD_MODNAME,                             \
 108                 .base = _base,                                          \
 109                 .map_type = _maptype,                                   \
 110                 .length = NUM_TYPE_ARGS(char*, __VA_ARGS__),            \
 111                 .class_names = _var##_classnames,                       \
 112         }
 113 #define NUM_TYPE_ARGS(eltype, ...)                              \
 114         (sizeof((eltype[]){__VA_ARGS__}) / sizeof(eltype))
 115
 116 /* encapsulate linker provided built-in (or module) dyndbg data */
 117 struct _ddebug_info {
 118         struct _ddebug *descs;
 119         struct ddebug_class_map *classes;
 120         unsigned int num_descs;
 121         unsigned int num_classes;
 122 };
 123
 124 struct ddebug_class_param {
 125         union {
 126                 unsigned long *bits;
 127                 unsigned int *lvl;
 128         };
 129         char flags[8];
 130         const struct ddebug_class_map *map;
 131 };
 132
 133 /*
 134  * pr_debug() and friends are globally enabled or modules have selectively
 135  * enabled them.
 136  */
 137 #if defined(CONFIG_DYNAMIC_DEBUG) || \
 138         (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
 139
 140 extern __printf(2, 3)
 141 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 142
 143 struct device;
 144
 145 extern __printf(3, 4)
 146 void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
 147                        const char *fmt, ...);
 148
 149 struct net_device;
 150
 151 extern __printf(3, 4)
 152 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
 153                           const struct net_device *dev,
 154                           const char *fmt, ...);
 155
 156 struct ib_device;
 157
 158 extern __printf(3, 4)
 159 void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 160                          const struct ib_device *ibdev,
 161                          const char *fmt, ...);
 162
 163 #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)       \
 164         static struct _ddebug  __aligned(8)                     \
 165         __section("__dyndbg") name = {                          \
 166                 .modname = KBUILD_MODNAME,                      \
 167                 .function = __func__,                           \
 168                 .filename = __FILE__,                           \
 169                 .format = (fmt),                                \
 170                 .lineno = __LINE__,                             \
 171                 .flags = _DPRINTK_FLAGS_DEFAULT,                \
 172                 .class_id = cls,                                \
 173                 _DPRINTK_KEY_INIT                               \
 174         };                                                      \
 175         BUILD_BUG_ON_MSG(cls > _DPRINTK_CLASS_DFLT,             \
 176                          "classid value overflow")
 177
 178 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)                \
 179         DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)
 180
 181 #ifdef CONFIG_JUMP_LABEL
 182
 183 #ifdef DEBUG
 184
 185 #define _DPRINTK_KEY_INIT .key.dd_key_true = (STATIC_KEY_TRUE_INIT)
 186
 187 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 188         static_branch_likely(&descriptor.key.dd_key_true)
 189 #else
 190 #define _DPRINTK_KEY_INIT .key.dd_key_false = (STATIC_KEY_FALSE_INIT)
 191
 192 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 193         static_branch_unlikely(&descriptor.key.dd_key_false)
 194 #endif
 195
 196 #else /* !CONFIG_JUMP_LABEL */
 197
 198 #define _DPRINTK_KEY_INIT
 199
 200 #ifdef DEBUG
 201 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 202         likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 203 #else
 204 #define DYNAMIC_DEBUG_BRANCH(descriptor) \
 205         unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
 206 #endif
 207
 208 #endif /* CONFIG_JUMP_LABEL */
 209
 210 /*
 211  * Factory macros: ($prefix)dynamic_func_call($suffix)
 212  *
 213  * Lower layer (with __ prefix) gets the callsite metadata, and wraps
 214  * the func inside a debug-branch/static-key construct.  Upper layer
 215  * (with _ prefix) does the UNIQUE_ID once, so that lower can ref the
 216  * name/label multiple times, and tie the elements together.
 217  * Multiple flavors:
 218  * (|_cls):     adds in _DPRINT_CLASS_DFLT as needed
 219  * (|_no_desc): former gets callsite descriptor as 1st arg (for prdbgs)
 220  */
 221 #define __dynamic_func_call_cls(id, cls, fmt, func, ...) do {   \
 222         DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);        \
 223         if (DYNAMIC_DEBUG_BRANCH(id))                           \
 224                 func(&id, ##__VA_ARGS__);                       \
 225 } while (0)
 226 #define __dynamic_func_call(id, fmt, func, ...)                         \
 227         __dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,           \
 228                                 func, ##__VA_ARGS__)
 229
 230 #define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {   \
 231         DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);                \
 232         if (DYNAMIC_DEBUG_BRANCH(id))                                   \
 233                 func(__VA_ARGS__);                                      \
 234 } while (0)
 235 #define __dynamic_func_call_no_desc(id, fmt, func, ...)                 \
 236         __dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,        \
 237                                         fmt, func, ##__VA_ARGS__)
 238
 239 /*
 240  * "Factory macro" for generating a call to func, guarded by a
 241  * DYNAMIC_DEBUG_BRANCH. The dynamic debug descriptor will be
 242  * initialized using the fmt argument. The function will be called with
 243  * the address of the descriptor as first argument, followed by all
 244  * the varargs. Note that fmt is repeated in invocations of this
 245  * macro.
 246  */
 247 #define _dynamic_func_call_cls(cls, fmt, func, ...)                     \
 248         __dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
 249 #define _dynamic_func_call(fmt, func, ...)                              \
 250         _dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
 251
 252 /*
 253  * A variant that does the same, except that the descriptor is not
 254  * passed as the first argument to the function; it is only called
 255  * with precisely the macro's varargs.
 256  */
 257 #define _dynamic_func_call_cls_no_desc(cls, fmt, func, ...)             \
 258         __dynamic_func_call_cls_no_desc(__UNIQUE_ID(ddebug), cls, fmt,  \
 259                                         func, ##__VA_ARGS__)
 260 #define _dynamic_func_call_no_desc(fmt, func, ...)                      \
 261         _dynamic_func_call_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt,        \
 262                                        func, ##__VA_ARGS__)
 263
 264 #define dynamic_pr_debug_cls(cls, fmt, ...)                             \
 265         _dynamic_func_call_cls(cls, fmt, __dynamic_pr_debug,            \
 266                            pr_fmt(fmt), ##__VA_ARGS__)
 267
 268 #define dynamic_pr_debug(fmt, ...)                              \
 269         _dynamic_func_call(fmt, __dynamic_pr_debug,             \
 270                            pr_fmt(fmt), ##__VA_ARGS__)
 271
 272 #define dynamic_dev_dbg(dev, fmt, ...)                          \
 273         _dynamic_func_call(fmt, __dynamic_dev_dbg,              \
 274                            dev, fmt, ##__VA_ARGS__)
 275
 276 #define dynamic_netdev_dbg(dev, fmt, ...)                       \
 277         _dynamic_func_call(fmt, __dynamic_netdev_dbg,           \
 278                            dev, fmt, ##__VA_ARGS__)
 279
 280 #define dynamic_ibdev_dbg(dev, fmt, ...)                        \
 281         _dynamic_func_call(fmt, __dynamic_ibdev_dbg,            \
 282                            dev, fmt, ##__VA_ARGS__)
 283
 284 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,              \
 285                          groupsize, buf, len, ascii)                    \
 286         _dynamic_func_call_no_desc(__builtin_constant_p(prefix_str) ? prefix_str : "hexdump", \
 287                                    print_hex_dump,                      \
 288                                    KERN_DEBUG, prefix_str, prefix_type, \
 289                                    rowsize, groupsize, buf, len, ascii)
 290
 291 /* for test only, generally expect drm.debug style macro wrappers */
 292 #define __pr_debug_cls(cls, fmt, ...) do {                      \
 293         BUILD_BUG_ON_MSG(!__builtin_constant_p(cls),            \
 294                          "expecting constant class int/enum");  \
 295         dynamic_pr_debug_cls(cls, fmt, ##__VA_ARGS__);          \
 296         } while (0)
 297
 298 #else /* !(CONFIG_DYNAMIC_DEBUG || (CONFIG_DYNAMIC_DEBUG_CORE && DYNAMIC_DEBUG_MODULE)) */
 299
 300 #include <linux/string.h>
 301 #include <linux/errno.h>
 302 #include <linux/printk.h>
 303
 304 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)
 305 #define DYNAMIC_DEBUG_BRANCH(descriptor) false
 306
 307 #define dynamic_pr_debug(fmt, ...)                                      \
 308         no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 309 #define dynamic_dev_dbg(dev, fmt, ...)                                  \
 310         dev_no_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__)
 311 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,              \
 312                          groupsize, buf, len, ascii)                    \
 313         do { if (0)                                                     \
 314                 print_hex_dump(KERN_DEBUG, prefix_str, prefix_type,     \
 315                                 rowsize, groupsize, buf, len, ascii);   \
 316         } while (0)
 317
 318 #endif /* CONFIG_DYNAMIC_DEBUG || (CONFIG_DYNAMIC_DEBUG_CORE && DYNAMIC_DEBUG_MODULE) */
 319
 320
 321 #ifdef CONFIG_DYNAMIC_DEBUG_CORE
 322
 323 extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
 324                                         const char *modname);
 325 struct kernel_param;
 326 int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp);
 327 int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp);
 328
 329 #else
 330
 331 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
 332                                                 const char *modname)
 333 {
 334         if (!strcmp(param, "dyndbg")) {
 335                 /* avoid pr_warn(), which wants pr_fmt() fully defined */
 336                 printk(KERN_WARNING "dyndbg param is supported only in "
 337                         "CONFIG_DYNAMIC_DEBUG builds\n");
 338                 return 0; /* allow and ignore */
 339         }
 340         return -EINVAL;
 341 }
 342
 343 struct kernel_param;
 344 static inline int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 345 { return 0; }
 346 static inline int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 347 { return 0; }
 348
 349 #endif
 350
 351
 352 extern const struct kernel_param_ops param_ops_dyndbg_classes;
 353
 354 #endif /* _DYNAMIC_DEBUG_H */