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))
20 #define __MODULE_INFO(tag, name, info) \
21 static const char __UNIQUE_ID(name)[] \
22 __used __attribute__((section(".modinfo"), unused, aligned(1))) \
23 = __stringify(tag) "=" info
25 /* This struct is here for syntactic coherency, it is not used */
26 #define __MODULE_INFO(tag, name, info) \
27 struct __UNIQUE_ID(name) {}
29 #define __MODULE_PARM_TYPE(name, _type) \
30 __MODULE_INFO(parmtype, name##type, #name ":" _type)
32 /* One for each parameter, describing how to use it. Some files do
33 multiple of these per line, so can't just use MODULE_INFO. */
34 #define MODULE_PARM_DESC(_parm, desc) \
35 __MODULE_INFO(parm, _parm, #_parm ":" desc)
40 * Flags available for kernel_param_ops
42 * NOARG - the parameter allows for no argument (foo instead of foo=1)
45 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
48 struct kernel_param_ops {
49 /* How the ops should behave */
51 /* Returns 0, or -errno. arg is in kp->arg. */
52 int (*set)(const char *val, const struct kernel_param *kp);
53 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
54 int (*get)(char *buffer, const struct kernel_param *kp);
55 /* Optional function to free kp->arg when module unloaded. */
56 void (*free)(void *arg);
60 * Flags available for kernel_param
62 * UNSAFE - the parameter is dangerous and setting it will taint the kernel
65 KERNEL_PARAM_FL_UNSAFE = (1 << 0)
70 const struct kernel_param_ops *ops;
76 const struct kparam_string *str;
77 const struct kparam_array *arr;
81 /* Special one for strings we want to copy into */
82 struct kparam_string {
87 /* Special one for arrays */
91 unsigned int elemsize;
93 const struct kernel_param_ops *ops;
98 * module_param - typesafe helper for a module/cmdline parameter
99 * @value: the variable to alter, and exposed parameter name.
100 * @type: the type of the parameter
101 * @perm: visibility in sysfs.
103 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
104 * ".") the kernel commandline parameter. Note that - is changed to _, so
105 * the user can use "foo-bar=1" even for variable "foo_bar".
107 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
108 * for world-readable, 0644 for root-writable, etc. Note that if it
109 * is writable, you may need to use kparam_block_sysfs_write() around
110 * accesses (esp. charp, which can be kfreed when it changes).
112 * The @type is simply pasted to refer to a param_ops_##type and a
113 * param_check_##type: for convenience many standard types are provided but
114 * you can create your own by defining those variables.
116 * Standard types are:
117 * byte, short, ushort, int, uint, long, ulong
118 * charp: a character pointer
119 * bool: a bool, values 0/1, y/n, Y/N.
120 * invbool: the above, only sense-reversed (N = true).
122 #define module_param(name, type, perm) \
123 module_param_named(name, name, type, perm)
126 * module_param_unsafe - same as module_param but taints kernel
128 #define module_param_unsafe(name, type, perm) \
129 module_param_named_unsafe(name, name, type, perm)
132 * module_param_named - typesafe helper for a renamed module/cmdline parameter
133 * @name: a valid C identifier which is the parameter name.
134 * @value: the actual lvalue to alter.
135 * @type: the type of the parameter
136 * @perm: visibility in sysfs.
138 * Usually it's a good idea to have variable names and user-exposed names the
139 * same, but that's harder if the variable must be non-static or is inside a
140 * structure. This allows exposure under a different name.
142 #define module_param_named(name, value, type, perm) \
143 param_check_##type(name, &(value)); \
144 module_param_cb(name, ¶m_ops_##type, &value, perm); \
145 __MODULE_PARM_TYPE(name, #type)
148 * module_param_named_unsafe - same as module_param_named but taints kernel
150 #define module_param_named_unsafe(name, value, type, perm) \
151 param_check_##type(name, &(value)); \
152 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \
153 __MODULE_PARM_TYPE(name, #type)
156 * module_param_cb - general callback for a module/cmdline parameter
157 * @name: a valid C identifier which is the parameter name.
158 * @ops: the set & get operations for this parameter.
159 * @perm: visibility in sysfs.
161 * The ops can have NULL set or get functions.
163 #define module_param_cb(name, ops, arg, perm) \
164 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
166 #define module_param_cb_unsafe(name, ops, arg, perm) \
167 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \
168 KERNEL_PARAM_FL_UNSAFE)
171 * <level>_param_cb - general callback for a module/cmdline parameter
172 * to be evaluated before certain initcall level
173 * @name: a valid C identifier which is the parameter name.
174 * @ops: the set & get operations for this parameter.
175 * @perm: visibility in sysfs.
177 * The ops can have NULL set or get functions.
179 #define __level_param_cb(name, ops, arg, perm, level) \
180 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
182 #define core_param_cb(name, ops, arg, perm) \
183 __level_param_cb(name, ops, arg, perm, 1)
185 #define postcore_param_cb(name, ops, arg, perm) \
186 __level_param_cb(name, ops, arg, perm, 2)
188 #define arch_param_cb(name, ops, arg, perm) \
189 __level_param_cb(name, ops, arg, perm, 3)
191 #define subsys_param_cb(name, ops, arg, perm) \
192 __level_param_cb(name, ops, arg, perm, 4)
194 #define fs_param_cb(name, ops, arg, perm) \
195 __level_param_cb(name, ops, arg, perm, 5)
197 #define device_param_cb(name, ops, arg, perm) \
198 __level_param_cb(name, ops, arg, perm, 6)
200 #define late_param_cb(name, ops, arg, perm) \
201 __level_param_cb(name, ops, arg, perm, 7)
203 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
204 read-only sections (which is part of respective UNIX ABI on these
205 platforms). So 'const' makes no sense and even causes compile failures
206 with some compilers. */
207 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
208 #define __moduleparam_const
210 #define __moduleparam_const const
213 /* This is the fundamental function for registering boot/module
215 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
216 /* Default value instead of permissions? */ \
217 static const char __param_str_##name[] = prefix #name; \
218 static struct kernel_param __moduleparam_const __param_##name \
220 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
221 = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \
222 level, flags, { arg } }
224 /* Obsolete - use module_param_cb() */
225 #define module_param_call(name, set, get, arg, perm) \
226 static struct kernel_param_ops __param_ops_##name = \
227 { 0, (void *)set, (void *)get }; \
228 __module_param_call(MODULE_PARAM_PREFIX, \
229 name, &__param_ops_##name, arg, \
230 (perm) + sizeof(__check_old_set_param(set))*0, -1, 0)
232 /* We don't get oldget: it's often a new-style param_get_uint, etc. */
234 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
240 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
241 * @name: the name of the parameter
243 * There's no point blocking write on a paramter that isn't writable via sysfs!
245 #define kparam_block_sysfs_write(name) \
247 BUG_ON(!(__param_##name.perm & 0222)); \
248 __kernel_param_lock(); \
252 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
253 * @name: the name of the parameter
255 #define kparam_unblock_sysfs_write(name) \
257 BUG_ON(!(__param_##name.perm & 0222)); \
258 __kernel_param_unlock(); \
262 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
263 * @name: the name of the parameter
265 * This also blocks sysfs writes.
267 #define kparam_block_sysfs_read(name) \
269 BUG_ON(!(__param_##name.perm & 0444)); \
270 __kernel_param_lock(); \
274 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
275 * @name: the name of the parameter
277 #define kparam_unblock_sysfs_read(name) \
279 BUG_ON(!(__param_##name.perm & 0444)); \
280 __kernel_param_unlock(); \
284 extern void __kernel_param_lock(void);
285 extern void __kernel_param_unlock(void);
287 static inline void __kernel_param_lock(void)
290 static inline void __kernel_param_unlock(void)
297 * core_param - define a historical core kernel parameter.
298 * @name: the name of the cmdline and sysfs parameter (often the same as var)
300 * @type: the type of the parameter
301 * @perm: visibility in sysfs
303 * core_param is just like module_param(), but cannot be modular and
304 * doesn't add a prefix (such as "printk."). This is for compatibility
305 * with __setup(), and it makes sense as truly core parameters aren't
306 * tied to the particular file they're in.
308 #define core_param(name, var, type, perm) \
309 param_check_##type(name, &(var)); \
310 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0)
314 * module_param_string - a char array parameter
315 * @name: the name of the parameter
316 * @string: the string variable
317 * @len: the maximum length of the string, incl. terminator
318 * @perm: visibility in sysfs.
320 * This actually copies the string when it's set (unlike type charp).
321 * @len is usually just sizeof(string).
323 #define module_param_string(name, string, len, perm) \
324 static const struct kparam_string __param_string_##name \
326 __module_param_call(MODULE_PARAM_PREFIX, name, \
328 .str = &__param_string_##name, perm, -1, 0);\
329 __MODULE_PARM_TYPE(name, "string")
332 * parameq - checks if two parameter names match
333 * @name1: parameter name 1
334 * @name2: parameter name 2
336 * Returns true if the two parameter names are equal.
337 * Dashes (-) are considered equal to underscores (_).
339 extern bool parameq(const char *name1, const char *name2);
342 * parameqn - checks if two parameter names match
343 * @name1: parameter name 1
344 * @name2: parameter name 2
345 * @n: the length to compare
347 * Similar to parameq(), except it compares @n characters.
349 extern bool parameqn(const char *name1, const char *name2, size_t n);
351 /* Called on module insert or kernel boot */
352 extern char *parse_args(const char *name,
354 const struct kernel_param *params,
358 int (*unknown)(char *param, char *val,
361 /* Called by module remove. */
363 extern void destroy_params(const struct kernel_param *params, unsigned num);
365 static inline void destroy_params(const struct kernel_param *params,
369 #endif /* !CONFIG_SYSFS */
371 /* All the helper functions */
372 /* The macros to do compile-time type checking stolen from Jakub
373 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
374 #define __param_check(name, p, type) \
375 static inline type __always_unused *__check_##name(void) { return(p); }
377 extern struct kernel_param_ops param_ops_byte;
378 extern int param_set_byte(const char *val, const struct kernel_param *kp);
379 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
380 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
382 extern struct kernel_param_ops param_ops_short;
383 extern int param_set_short(const char *val, const struct kernel_param *kp);
384 extern int param_get_short(char *buffer, const struct kernel_param *kp);
385 #define param_check_short(name, p) __param_check(name, p, short)
387 extern struct kernel_param_ops param_ops_ushort;
388 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
389 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
390 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
392 extern struct kernel_param_ops param_ops_int;
393 extern int param_set_int(const char *val, const struct kernel_param *kp);
394 extern int param_get_int(char *buffer, const struct kernel_param *kp);
395 #define param_check_int(name, p) __param_check(name, p, int)
397 extern struct kernel_param_ops param_ops_uint;
398 extern int param_set_uint(const char *val, const struct kernel_param *kp);
399 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
400 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
402 extern struct kernel_param_ops param_ops_long;
403 extern int param_set_long(const char *val, const struct kernel_param *kp);
404 extern int param_get_long(char *buffer, const struct kernel_param *kp);
405 #define param_check_long(name, p) __param_check(name, p, long)
407 extern struct kernel_param_ops param_ops_ulong;
408 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
409 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
410 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
412 extern struct kernel_param_ops param_ops_ullong;
413 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
414 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
415 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
417 extern struct kernel_param_ops param_ops_charp;
418 extern int param_set_charp(const char *val, const struct kernel_param *kp);
419 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
420 #define param_check_charp(name, p) __param_check(name, p, char *)
422 /* We used to allow int as well as bool. We're taking that away! */
423 extern struct kernel_param_ops param_ops_bool;
424 extern int param_set_bool(const char *val, const struct kernel_param *kp);
425 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
426 #define param_check_bool(name, p) __param_check(name, p, bool)
428 extern struct kernel_param_ops param_ops_invbool;
429 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
430 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
431 #define param_check_invbool(name, p) __param_check(name, p, bool)
433 /* An int, which can only be set like a bool (though it shows as an int). */
434 extern struct kernel_param_ops param_ops_bint;
435 extern int param_set_bint(const char *val, const struct kernel_param *kp);
436 #define param_get_bint param_get_int
437 #define param_check_bint param_check_int
440 * module_param_array - a parameter which is an array of some type
441 * @name: the name of the array variable
442 * @type: the type, as per module_param()
443 * @nump: optional pointer filled in with the number written
444 * @perm: visibility in sysfs
446 * Input and output are as comma-separated values. Commas inside values
447 * don't work properly (eg. an array of charp).
449 * ARRAY_SIZE(@name) is used to determine the number of elements in the
450 * array, so the definition must be visible.
452 #define module_param_array(name, type, nump, perm) \
453 module_param_array_named(name, name, type, nump, perm)
456 * module_param_array_named - renamed parameter which is an array of some type
457 * @name: a valid C identifier which is the parameter name
458 * @array: the name of the array variable
459 * @type: the type, as per module_param()
460 * @nump: optional pointer filled in with the number written
461 * @perm: visibility in sysfs
463 * This exposes a different name than the actual variable name. See
464 * module_param_named() for why this might be necessary.
466 #define module_param_array_named(name, array, type, nump, perm) \
467 param_check_##type(name, &(array)[0]); \
468 static const struct kparam_array __param_arr_##name \
469 = { .max = ARRAY_SIZE(array), .num = nump, \
470 .ops = ¶m_ops_##type, \
471 .elemsize = sizeof(array[0]), .elem = array }; \
472 __module_param_call(MODULE_PARAM_PREFIX, name, \
474 .arr = &__param_arr_##name, \
476 __MODULE_PARM_TYPE(name, "array of " #type)
478 extern struct kernel_param_ops param_array_ops;
480 extern struct kernel_param_ops param_ops_string;
481 extern int param_set_copystring(const char *val, const struct kernel_param *);
482 extern int param_get_string(char *buffer, const struct kernel_param *kp);
484 /* for exporting parameters in /sys/module/.../parameters */
488 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
489 extern int module_param_sysfs_setup(struct module *mod,
490 const struct kernel_param *kparam,
491 unsigned int num_params);
493 extern void module_param_sysfs_remove(struct module *mod);
495 static inline int module_param_sysfs_setup(struct module *mod,
496 const struct kernel_param *kparam,
497 unsigned int num_params)
502 static inline void module_param_sysfs_remove(struct module *mod)
506 #endif /* _LINUX_MODULE_PARAMS_H */