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>
8 /* You can override this manually, but generally this should match the
11 #define MODULE_PARAM_PREFIX /* empty */
13 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
16 /* Chosen so that structs with an unsigned long line up. */
17 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
19 #define ___module_cat(a,b) __mod_ ## a ## b
20 #define __module_cat(a,b) ___module_cat(a,b)
22 #define __MODULE_INFO(tag, name, info) \
23 static const char __module_cat(name,__LINE__)[] \
24 __used __attribute__((section(".modinfo"), unused, aligned(1))) \
25 = __stringify(tag) "=" info
27 /* This struct is here for syntactic coherency, it is not used */
28 #define __MODULE_INFO(tag, name, info) \
29 struct __module_cat(name,__LINE__) {}
31 #define __MODULE_PARM_TYPE(name, _type) \
32 __MODULE_INFO(parmtype, name##type, #name ":" _type)
34 /* One for each parameter, describing how to use it. Some files do
35 multiple of these per line, so can't just use MODULE_INFO. */
36 #define MODULE_PARM_DESC(_parm, desc) \
37 __MODULE_INFO(parm, _parm, #_parm ":" desc)
41 struct kernel_param_ops {
42 /* Returns 0, or -errno. arg is in kp->arg. */
43 int (*set)(const char *val, const struct kernel_param *kp);
44 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
45 int (*get)(char *buffer, const struct kernel_param *kp);
46 /* Optional function to free kp->arg when module unloaded. */
47 void (*free)(void *arg);
52 const struct kernel_param_ops *ops;
57 const struct kparam_string *str;
58 const struct kparam_array *arr;
62 /* Special one for strings we want to copy into */
63 struct kparam_string {
68 /* Special one for arrays */
72 unsigned int elemsize;
74 const struct kernel_param_ops *ops;
79 * module_param - typesafe helper for a module/cmdline parameter
80 * @value: the variable to alter, and exposed parameter name.
81 * @type: the type of the parameter
82 * @perm: visibility in sysfs.
84 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
85 * ".") the kernel commandline parameter. Note that - is changed to _, so
86 * the user can use "foo-bar=1" even for variable "foo_bar".
88 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
89 * for world-readable, 0644 for root-writable, etc. Note that if it
90 * is writable, you may need to use kparam_block_sysfs_write() around
91 * accesses (esp. charp, which can be kfreed when it changes).
93 * The @type is simply pasted to refer to a param_ops_##type and a
94 * param_check_##type: for convenience many standard types are provided but
95 * you can create your own by defining those variables.
98 * byte, short, ushort, int, uint, long, ulong
99 * charp: a character pointer
100 * bool: a bool, values 0/1, y/n, Y/N.
101 * invbool: the above, only sense-reversed (N = true).
103 #define module_param(name, type, perm) \
104 module_param_named(name, name, type, perm)
107 * module_param_named - typesafe helper for a renamed module/cmdline parameter
108 * @name: a valid C identifier which is the parameter name.
109 * @value: the actual lvalue to alter.
110 * @type: the type of the parameter
111 * @perm: visibility in sysfs.
113 * Usually it's a good idea to have variable names and user-exposed names the
114 * same, but that's harder if the variable must be non-static or is inside a
115 * structure. This allows exposure under a different name.
117 #define module_param_named(name, value, type, perm) \
118 param_check_##type(name, &(value)); \
119 module_param_cb(name, ¶m_ops_##type, &value, perm); \
120 __MODULE_PARM_TYPE(name, #type)
123 * module_param_cb - general callback for a module/cmdline parameter
124 * @name: a valid C identifier which is the parameter name.
125 * @ops: the set & get operations for this parameter.
126 * @perm: visibility in sysfs.
128 * The ops can have NULL set or get functions.
130 #define module_param_cb(name, ops, arg, perm) \
131 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm)
133 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
134 read-only sections (which is part of respective UNIX ABI on these
135 platforms). So 'const' makes no sense and even causes compile failures
136 with some compilers. */
137 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
138 #define __moduleparam_const
140 #define __moduleparam_const const
143 /* This is the fundamental function for registering boot/module
145 #define __module_param_call(prefix, name, ops, arg, perm) \
146 /* Default value instead of permissions? */ \
147 static int __param_perm_check_##name __attribute__((unused)) = \
148 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
149 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
150 static const char __param_str_##name[] = prefix #name; \
151 static struct kernel_param __moduleparam_const __param_##name \
153 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
154 = { __param_str_##name, ops, perm, 0, { arg } }
156 /* Obsolete - use module_param_cb() */
157 #define module_param_call(name, set, get, arg, perm) \
158 static struct kernel_param_ops __param_ops_##name = \
159 { (void *)set, (void *)get }; \
160 __module_param_call(MODULE_PARAM_PREFIX, \
161 name, &__param_ops_##name, arg, \
162 (perm) + sizeof(__check_old_set_param(set))*0)
164 /* We don't get oldget: it's often a new-style param_get_uint, etc. */
166 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
172 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
173 * @name: the name of the parameter
175 * There's no point blocking write on a paramter that isn't writable via sysfs!
177 #define kparam_block_sysfs_write(name) \
179 BUG_ON(!(__param_##name.perm & 0222)); \
180 __kernel_param_lock(); \
184 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
185 * @name: the name of the parameter
187 #define kparam_unblock_sysfs_write(name) \
189 BUG_ON(!(__param_##name.perm & 0222)); \
190 __kernel_param_unlock(); \
194 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
195 * @name: the name of the parameter
197 * This also blocks sysfs writes.
199 #define kparam_block_sysfs_read(name) \
201 BUG_ON(!(__param_##name.perm & 0444)); \
202 __kernel_param_lock(); \
206 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
207 * @name: the name of the parameter
209 #define kparam_unblock_sysfs_read(name) \
211 BUG_ON(!(__param_##name.perm & 0444)); \
212 __kernel_param_unlock(); \
216 extern void __kernel_param_lock(void);
217 extern void __kernel_param_unlock(void);
219 static inline void __kernel_param_lock(void)
222 static inline void __kernel_param_unlock(void)
229 * core_param - define a historical core kernel parameter.
230 * @name: the name of the cmdline and sysfs parameter (often the same as var)
232 * @type: the type of the parameter
233 * @perm: visibility in sysfs
235 * core_param is just like module_param(), but cannot be modular and
236 * doesn't add a prefix (such as "printk."). This is for compatibility
237 * with __setup(), and it makes sense as truly core parameters aren't
238 * tied to the particular file they're in.
240 #define core_param(name, var, type, perm) \
241 param_check_##type(name, &(var)); \
242 __module_param_call("", name, ¶m_ops_##type, &var, perm)
246 * module_param_string - a char array parameter
247 * @name: the name of the parameter
248 * @string: the string variable
249 * @len: the maximum length of the string, incl. terminator
250 * @perm: visibility in sysfs.
252 * This actually copies the string when it's set (unlike type charp).
253 * @len is usually just sizeof(string).
255 #define module_param_string(name, string, len, perm) \
256 static const struct kparam_string __param_string_##name \
258 __module_param_call(MODULE_PARAM_PREFIX, name, \
260 .str = &__param_string_##name, perm); \
261 __MODULE_PARM_TYPE(name, "string")
264 * parameq - checks if two parameter names match
265 * @name1: parameter name 1
266 * @name2: parameter name 2
268 * Returns true if the two parameter names are equal.
269 * Dashes (-) are considered equal to underscores (_).
271 extern bool parameq(const char *name1, const char *name2);
274 * parameqn - checks if two parameter names match
275 * @name1: parameter name 1
276 * @name2: parameter name 2
277 * @n: the length to compare
279 * Similar to parameq(), except it compares @n characters.
281 extern bool parameqn(const char *name1, const char *name2, size_t n);
283 /* Called on module insert or kernel boot */
284 extern int parse_args(const char *name,
286 const struct kernel_param *params,
288 int (*unknown)(char *param, char *val));
290 /* Called by module remove. */
292 extern void destroy_params(const struct kernel_param *params, unsigned num);
294 static inline void destroy_params(const struct kernel_param *params,
298 #endif /* !CONFIG_SYSFS */
300 /* All the helper functions */
301 /* The macros to do compile-time type checking stolen from Jakub
302 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
303 #define __param_check(name, p, type) \
304 static inline type *__check_##name(void) { return(p); }
306 extern struct kernel_param_ops param_ops_byte;
307 extern int param_set_byte(const char *val, const struct kernel_param *kp);
308 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
309 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
311 extern struct kernel_param_ops param_ops_short;
312 extern int param_set_short(const char *val, const struct kernel_param *kp);
313 extern int param_get_short(char *buffer, const struct kernel_param *kp);
314 #define param_check_short(name, p) __param_check(name, p, short)
316 extern struct kernel_param_ops param_ops_ushort;
317 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
318 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
319 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
321 extern struct kernel_param_ops param_ops_int;
322 extern int param_set_int(const char *val, const struct kernel_param *kp);
323 extern int param_get_int(char *buffer, const struct kernel_param *kp);
324 #define param_check_int(name, p) __param_check(name, p, int)
326 extern struct kernel_param_ops param_ops_uint;
327 extern int param_set_uint(const char *val, const struct kernel_param *kp);
328 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
329 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
331 extern struct kernel_param_ops param_ops_long;
332 extern int param_set_long(const char *val, const struct kernel_param *kp);
333 extern int param_get_long(char *buffer, const struct kernel_param *kp);
334 #define param_check_long(name, p) __param_check(name, p, long)
336 extern struct kernel_param_ops param_ops_ulong;
337 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
338 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
339 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
341 extern struct kernel_param_ops param_ops_charp;
342 extern int param_set_charp(const char *val, const struct kernel_param *kp);
343 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
344 #define param_check_charp(name, p) __param_check(name, p, char *)
346 /* We used to allow int as well as bool. We're taking that away! */
347 extern struct kernel_param_ops param_ops_bool;
348 extern int param_set_bool(const char *val, const struct kernel_param *kp);
349 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
350 #define param_check_bool(name, p) __param_check(name, p, bool)
352 extern struct kernel_param_ops param_ops_invbool;
353 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
354 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
355 #define param_check_invbool(name, p) __param_check(name, p, bool)
357 /* An int, which can only be set like a bool (though it shows as an int). */
358 extern struct kernel_param_ops param_ops_bint;
359 extern int param_set_bint(const char *val, const struct kernel_param *kp);
360 #define param_get_bint param_get_int
361 #define param_check_bint param_check_int
364 * module_param_array - a parameter which is an array of some type
365 * @name: the name of the array variable
366 * @type: the type, as per module_param()
367 * @nump: optional pointer filled in with the number written
368 * @perm: visibility in sysfs
370 * Input and output are as comma-separated values. Commas inside values
371 * don't work properly (eg. an array of charp).
373 * ARRAY_SIZE(@name) is used to determine the number of elements in the
374 * array, so the definition must be visible.
376 #define module_param_array(name, type, nump, perm) \
377 module_param_array_named(name, name, type, nump, perm)
380 * module_param_array_named - renamed parameter which is an array of some type
381 * @name: a valid C identifier which is the parameter name
382 * @array: the name of the array variable
383 * @type: the type, as per module_param()
384 * @nump: optional pointer filled in with the number written
385 * @perm: visibility in sysfs
387 * This exposes a different name than the actual variable name. See
388 * module_param_named() for why this might be necessary.
390 #define module_param_array_named(name, array, type, nump, perm) \
391 param_check_##type(name, &(array)[0]); \
392 static const struct kparam_array __param_arr_##name \
393 = { .max = ARRAY_SIZE(array), .num = nump, \
394 .ops = ¶m_ops_##type, \
395 .elemsize = sizeof(array[0]), .elem = array }; \
396 __module_param_call(MODULE_PARAM_PREFIX, name, \
398 .arr = &__param_arr_##name, \
400 __MODULE_PARM_TYPE(name, "array of " #type)
402 extern struct kernel_param_ops param_array_ops;
404 extern struct kernel_param_ops param_ops_string;
405 extern int param_set_copystring(const char *val, const struct kernel_param *);
406 extern int param_get_string(char *buffer, const struct kernel_param *kp);
408 /* for exporting parameters in /sys/parameters */
412 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
413 extern int module_param_sysfs_setup(struct module *mod,
414 const struct kernel_param *kparam,
415 unsigned int num_params);
417 extern void module_param_sysfs_remove(struct module *mod);
419 static inline int module_param_sysfs_setup(struct module *mod,
420 const struct kernel_param *kparam,
421 unsigned int num_params)
426 static inline void module_param_sysfs_remove(struct module *mod)
430 #endif /* _LINUX_MODULE_PARAMS_H */