xref: /openbmc/linux/include/linux/dynamic_debug.h (revision 842b6b16)
1 #ifndef _DYNAMIC_DEBUG_H
2 #define _DYNAMIC_DEBUG_H
3 
4 /*
5  * An instance of this structure is created in a special
6  * ELF section at every dynamic debug callsite.  At runtime,
7  * the special section is treated as an array of these.
8  */
9 struct _ddebug {
10 	/*
11 	 * These fields are used to drive the user interface
12 	 * for selecting and displaying debug callsites.
13 	 */
14 	const char *modname;
15 	const char *function;
16 	const char *filename;
17 	const char *format;
18 	unsigned int lineno:18;
19 	/*
20 	 * The flags field controls the behaviour at the callsite.
21 	 * The bits here are changed dynamically when the user
22 	 * writes commands to <debugfs>/dynamic_debug/control
23 	 */
24 #define _DPRINTK_FLAGS_NONE	0
25 #define _DPRINTK_FLAGS_PRINT	(1<<0) /* printk() a message using the format */
26 #define _DPRINTK_FLAGS_INCL_MODNAME	(1<<1)
27 #define _DPRINTK_FLAGS_INCL_FUNCNAME	(1<<2)
28 #define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)
29 #define _DPRINTK_FLAGS_INCL_TID		(1<<4)
30 #if defined DEBUG
31 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
32 #else
33 #define _DPRINTK_FLAGS_DEFAULT 0
34 #endif
35 	unsigned int flags:8;
36 } __attribute__((aligned(8)));
37 
38 
39 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
40 				const char *modname);
41 
42 #if defined(CONFIG_DYNAMIC_DEBUG)
43 extern int ddebug_remove_module(const char *mod_name);
44 extern __printf(2, 3)
45 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
46 
47 extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
48 					const char *modname);
49 
50 struct device;
51 
52 extern __printf(3, 4)
53 void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev,
54 		       const char *fmt, ...);
55 
56 struct net_device;
57 
58 extern __printf(3, 4)
59 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
60 			  const struct net_device *dev,
61 			  const char *fmt, ...);
62 
63 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\
64 	static struct _ddebug  __aligned(8)			\
65 	__attribute__((section("__verbose"))) name = {		\
66 		.modname = KBUILD_MODNAME,			\
67 		.function = __func__,				\
68 		.filename = __FILE__,				\
69 		.format = (fmt),				\
70 		.lineno = __LINE__,				\
71 		.flags =  _DPRINTK_FLAGS_DEFAULT,		\
72 	}
73 
74 #define dynamic_pr_debug(fmt, ...)				\
75 do {								\
76 	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);		\
77 	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT))	\
78 		__dynamic_pr_debug(&descriptor, pr_fmt(fmt),	\
79 				   ##__VA_ARGS__);		\
80 } while (0)
81 
82 #define dynamic_dev_dbg(dev, fmt, ...)				\
83 do {								\
84 	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);		\
85 	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT))	\
86 		__dynamic_dev_dbg(&descriptor, dev, fmt,	\
87 				  ##__VA_ARGS__);		\
88 } while (0)
89 
90 #define dynamic_netdev_dbg(dev, fmt, ...)			\
91 do {								\
92 	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);		\
93 	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT))	\
94 		__dynamic_netdev_dbg(&descriptor, dev, fmt,	\
95 				     ##__VA_ARGS__);		\
96 } while (0)
97 
98 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,	\
99 			 groupsize, buf, len, ascii)		\
100 do {								\
101 	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor,		\
102 		__builtin_constant_p(prefix_str) ? prefix_str : "hexdump");\
103 	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT))	\
104 		print_hex_dump(KERN_DEBUG, prefix_str,		\
105 			       prefix_type, rowsize, groupsize,	\
106 			       buf, len, ascii);		\
107 } while (0)
108 
109 #else
110 
111 #include <linux/string.h>
112 #include <linux/errno.h>
113 
114 static inline int ddebug_remove_module(const char *mod)
115 {
116 	return 0;
117 }
118 
119 static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
120 						const char *modname)
121 {
122 	if (strstr(param, "dyndbg")) {
123 		/* avoid pr_warn(), which wants pr_fmt() fully defined */
124 		printk(KERN_WARNING "dyndbg param is supported only in "
125 			"CONFIG_DYNAMIC_DEBUG builds\n");
126 		return 0; /* allow and ignore */
127 	}
128 	return -EINVAL;
129 }
130 
131 #define dynamic_pr_debug(fmt, ...)					\
132 	do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
133 #define dynamic_dev_dbg(dev, fmt, ...)					\
134 	do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
135 #endif
136 
137 #endif
138