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 	do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
309 #define dynamic_dev_dbg(dev, fmt, ...)					\
310 	do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
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 
ddebug_dyndbg_module_param_cb(char * param,char * val,const char * modname)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;
param_set_dyndbg_classes(const char * instr,const struct kernel_param * kp)344 static inline int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
345 { return 0; }
param_get_dyndbg_classes(char * buffer,const struct kernel_param * kp)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 */
355