xref: /linux/include/linux/moduleparam.h (revision f15cbe6f1a4b4d9df59142fc8e4abb973302cf44)
1 #ifndef _LINUX_MODULE_PARAMS_H
2 #define _LINUX_MODULE_PARAMS_H
3 /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
4 #include <linux/init.h>
5 #include <linux/stringify.h>
6 #include <linux/kernel.h>
7 
8 /* You can override this manually, but generally this should match the
9    module name. */
10 #ifdef MODULE
11 #define MODULE_PARAM_PREFIX /* empty */
12 #else
13 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
14 #endif
15 
16 #ifdef MODULE
17 #define ___module_cat(a,b) __mod_ ## a ## b
18 #define __module_cat(a,b) ___module_cat(a,b)
19 #define __MODULE_INFO(tag, name, info)					  \
20 static const char __module_cat(name,__LINE__)[]				  \
21   __used								  \
22   __attribute__((section(".modinfo"),unused)) = __stringify(tag) "=" info
23 #else  /* !MODULE */
24 #define __MODULE_INFO(tag, name, info)
25 #endif
26 #define __MODULE_PARM_TYPE(name, _type)					  \
27   __MODULE_INFO(parmtype, name##type, #name ":" _type)
28 
29 struct kernel_param;
30 
31 /* Returns 0, or -errno.  arg is in kp->arg. */
32 typedef int (*param_set_fn)(const char *val, struct kernel_param *kp);
33 /* Returns length written or -errno.  Buffer is 4k (ie. be short!) */
34 typedef int (*param_get_fn)(char *buffer, struct kernel_param *kp);
35 
36 struct kernel_param {
37 	const char *name;
38 	unsigned int perm;
39 	param_set_fn set;
40 	param_get_fn get;
41 	union {
42 		void *arg;
43 		const struct kparam_string *str;
44 		const struct kparam_array *arr;
45 	};
46 };
47 
48 /* Special one for strings we want to copy into */
49 struct kparam_string {
50 	unsigned int maxlen;
51 	char *string;
52 };
53 
54 /* Special one for arrays */
55 struct kparam_array
56 {
57 	unsigned int max;
58 	unsigned int *num;
59 	param_set_fn set;
60 	param_get_fn get;
61 	unsigned int elemsize;
62 	void *elem;
63 };
64 
65 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
66    read-only sections (which is part of respective UNIX ABI on these
67    platforms). So 'const' makes no sense and even causes compile failures
68    with some compilers. */
69 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
70 #define __moduleparam_const
71 #else
72 #define __moduleparam_const const
73 #endif
74 
75 /* This is the fundamental function for registering boot/module
76    parameters.  perm sets the visibility in sysfs: 000 means it's
77    not there, read bits mean it's readable, write bits mean it's
78    writable. */
79 #define __module_param_call(prefix, name, set, get, arg, perm)		\
80 	/* Default value instead of permissions? */			\
81 	static int __param_perm_check_##name __attribute__((unused)) =	\
82 	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2));	\
83 	static const char __param_str_##name[] = prefix #name;		\
84 	static struct kernel_param __moduleparam_const __param_##name	\
85 	__used								\
86     __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
87 	= { __param_str_##name, perm, set, get, { arg } }
88 
89 #define module_param_call(name, set, get, arg, perm)			      \
90 	__module_param_call(MODULE_PARAM_PREFIX, name, set, get, arg, perm)
91 
92 /* Helper functions: type is byte, short, ushort, int, uint, long,
93    ulong, charp, bool or invbool, or XXX if you define param_get_XXX,
94    param_set_XXX and param_check_XXX. */
95 #define module_param_named(name, value, type, perm)			   \
96 	param_check_##type(name, &(value));				   \
97 	module_param_call(name, param_set_##type, param_get_##type, &value, perm); \
98 	__MODULE_PARM_TYPE(name, #type)
99 
100 #define module_param(name, type, perm)				\
101 	module_param_named(name, name, type, perm)
102 
103 /* Actually copy string: maxlen param is usually sizeof(string). */
104 #define module_param_string(name, string, len, perm)			\
105 	static const struct kparam_string __param_string_##name		\
106 		= { len, string };					\
107 	module_param_call(name, param_set_copystring, param_get_string,	\
108 			  .str = &__param_string_##name, perm);		\
109 	__MODULE_PARM_TYPE(name, "string")
110 
111 /* Called on module insert or kernel boot */
112 extern int parse_args(const char *name,
113 		      char *args,
114 		      struct kernel_param *params,
115 		      unsigned num,
116 		      int (*unknown)(char *param, char *val));
117 
118 /* All the helper functions */
119 /* The macros to do compile-time type checking stolen from Jakub
120    Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
121 #define __param_check(name, p, type) \
122 	static inline type *__check_##name(void) { return(p); }
123 
124 extern int param_set_byte(const char *val, struct kernel_param *kp);
125 extern int param_get_byte(char *buffer, struct kernel_param *kp);
126 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
127 
128 extern int param_set_short(const char *val, struct kernel_param *kp);
129 extern int param_get_short(char *buffer, struct kernel_param *kp);
130 #define param_check_short(name, p) __param_check(name, p, short)
131 
132 extern int param_set_ushort(const char *val, struct kernel_param *kp);
133 extern int param_get_ushort(char *buffer, struct kernel_param *kp);
134 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
135 
136 extern int param_set_int(const char *val, struct kernel_param *kp);
137 extern int param_get_int(char *buffer, struct kernel_param *kp);
138 #define param_check_int(name, p) __param_check(name, p, int)
139 
140 extern int param_set_uint(const char *val, struct kernel_param *kp);
141 extern int param_get_uint(char *buffer, struct kernel_param *kp);
142 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
143 
144 extern int param_set_long(const char *val, struct kernel_param *kp);
145 extern int param_get_long(char *buffer, struct kernel_param *kp);
146 #define param_check_long(name, p) __param_check(name, p, long)
147 
148 extern int param_set_ulong(const char *val, struct kernel_param *kp);
149 extern int param_get_ulong(char *buffer, struct kernel_param *kp);
150 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
151 
152 extern int param_set_charp(const char *val, struct kernel_param *kp);
153 extern int param_get_charp(char *buffer, struct kernel_param *kp);
154 #define param_check_charp(name, p) __param_check(name, p, char *)
155 
156 extern int param_set_bool(const char *val, struct kernel_param *kp);
157 extern int param_get_bool(char *buffer, struct kernel_param *kp);
158 #define param_check_bool(name, p) __param_check(name, p, int)
159 
160 extern int param_set_invbool(const char *val, struct kernel_param *kp);
161 extern int param_get_invbool(char *buffer, struct kernel_param *kp);
162 #define param_check_invbool(name, p) __param_check(name, p, int)
163 
164 /* Comma-separated array: *nump is set to number they actually specified. */
165 #define module_param_array_named(name, array, type, nump, perm)		\
166 	static const struct kparam_array __param_arr_##name		\
167 	= { ARRAY_SIZE(array), nump, param_set_##type, param_get_##type,\
168 	    sizeof(array[0]), array };					\
169 	module_param_call(name, param_array_set, param_array_get, 	\
170 			  .arr = &__param_arr_##name, perm);		\
171 	__MODULE_PARM_TYPE(name, "array of " #type)
172 
173 #define module_param_array(name, type, nump, perm)		\
174 	module_param_array_named(name, name, type, nump, perm)
175 
176 extern int param_array_set(const char *val, struct kernel_param *kp);
177 extern int param_array_get(char *buffer, struct kernel_param *kp);
178 
179 extern int param_set_copystring(const char *val, struct kernel_param *kp);
180 extern int param_get_string(char *buffer, struct kernel_param *kp);
181 
182 /* for exporting parameters in /sys/parameters */
183 
184 struct module;
185 
186 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
187 extern int module_param_sysfs_setup(struct module *mod,
188 				    struct kernel_param *kparam,
189 				    unsigned int num_params);
190 
191 extern void module_param_sysfs_remove(struct module *mod);
192 #else
193 static inline int module_param_sysfs_setup(struct module *mod,
194 			     struct kernel_param *kparam,
195 			     unsigned int num_params)
196 {
197 	return 0;
198 }
199 
200 static inline void module_param_sysfs_remove(struct module *mod)
201 { }
202 #endif
203 
204 #endif /* _LINUX_MODULE_PARAMS_H */
205