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 extern const struct kernel_param __start___param[], __stop___param[];
83 /* Special one for strings we want to copy into */
84 struct kparam_string {
89 /* Special one for arrays */
93 unsigned int elemsize;
95 const struct kernel_param_ops *ops;
100 * module_param - typesafe helper for a module/cmdline parameter
101 * @value: the variable to alter, and exposed parameter name.
102 * @type: the type of the parameter
103 * @perm: visibility in sysfs.
105 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
106 * ".") the kernel commandline parameter. Note that - is changed to _, so
107 * the user can use "foo-bar=1" even for variable "foo_bar".
109 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
110 * for world-readable, 0644 for root-writable, etc. Note that if it
111 * is writable, you may need to use kparam_block_sysfs_write() around
112 * accesses (esp. charp, which can be kfreed when it changes).
114 * The @type is simply pasted to refer to a param_ops_##type and a
115 * param_check_##type: for convenience many standard types are provided but
116 * you can create your own by defining those variables.
118 * Standard types are:
119 * byte, short, ushort, int, uint, long, ulong
120 * charp: a character pointer
121 * bool: a bool, values 0/1, y/n, Y/N.
122 * invbool: the above, only sense-reversed (N = true).
124 #define module_param(name, type, perm) \
125 module_param_named(name, name, type, perm)
128 * module_param_unsafe - same as module_param but taints kernel
130 #define module_param_unsafe(name, type, perm) \
131 module_param_named_unsafe(name, name, type, perm)
134 * module_param_named - typesafe helper for a renamed module/cmdline parameter
135 * @name: a valid C identifier which is the parameter name.
136 * @value: the actual lvalue to alter.
137 * @type: the type of the parameter
138 * @perm: visibility in sysfs.
140 * Usually it's a good idea to have variable names and user-exposed names the
141 * same, but that's harder if the variable must be non-static or is inside a
142 * structure. This allows exposure under a different name.
144 #define module_param_named(name, value, type, perm) \
145 param_check_##type(name, &(value)); \
146 module_param_cb(name, ¶m_ops_##type, &value, perm); \
147 __MODULE_PARM_TYPE(name, #type)
150 * module_param_named_unsafe - same as module_param_named but taints kernel
152 #define module_param_named_unsafe(name, value, type, perm) \
153 param_check_##type(name, &(value)); \
154 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \
155 __MODULE_PARM_TYPE(name, #type)
158 * module_param_cb - general callback for a module/cmdline parameter
159 * @name: a valid C identifier which is the parameter name.
160 * @ops: the set & get operations for this parameter.
161 * @perm: visibility in sysfs.
163 * The ops can have NULL set or get functions.
165 #define module_param_cb(name, ops, arg, perm) \
166 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
168 #define module_param_cb_unsafe(name, ops, arg, perm) \
169 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \
170 KERNEL_PARAM_FL_UNSAFE)
173 * <level>_param_cb - general callback for a module/cmdline parameter
174 * to be evaluated before certain initcall level
175 * @name: a valid C identifier which is the parameter name.
176 * @ops: the set & get operations for this parameter.
177 * @perm: visibility in sysfs.
179 * The ops can have NULL set or get functions.
181 #define __level_param_cb(name, ops, arg, perm, level) \
182 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
184 #define core_param_cb(name, ops, arg, perm) \
185 __level_param_cb(name, ops, arg, perm, 1)
187 #define postcore_param_cb(name, ops, arg, perm) \
188 __level_param_cb(name, ops, arg, perm, 2)
190 #define arch_param_cb(name, ops, arg, perm) \
191 __level_param_cb(name, ops, arg, perm, 3)
193 #define subsys_param_cb(name, ops, arg, perm) \
194 __level_param_cb(name, ops, arg, perm, 4)
196 #define fs_param_cb(name, ops, arg, perm) \
197 __level_param_cb(name, ops, arg, perm, 5)
199 #define device_param_cb(name, ops, arg, perm) \
200 __level_param_cb(name, ops, arg, perm, 6)
202 #define late_param_cb(name, ops, arg, perm) \
203 __level_param_cb(name, ops, arg, perm, 7)
205 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
206 read-only sections (which is part of respective UNIX ABI on these
207 platforms). So 'const' makes no sense and even causes compile failures
208 with some compilers. */
209 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
210 #define __moduleparam_const
212 #define __moduleparam_const const
215 /* This is the fundamental function for registering boot/module
217 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
218 /* Default value instead of permissions? */ \
219 static const char __param_str_##name[] = prefix #name; \
220 static struct kernel_param __moduleparam_const __param_##name \
222 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
223 = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \
224 level, flags, { arg } }
226 /* Obsolete - use module_param_cb() */
227 #define module_param_call(name, set, get, arg, perm) \
228 static struct kernel_param_ops __param_ops_##name = \
229 { .flags = 0, (void *)set, (void *)get }; \
230 __module_param_call(MODULE_PARAM_PREFIX, \
231 name, &__param_ops_##name, arg, \
232 (perm) + sizeof(__check_old_set_param(set))*0, -1, 0)
234 /* We don't get oldget: it's often a new-style param_get_uint, etc. */
236 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
242 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
243 * @name: the name of the parameter
245 * There's no point blocking write on a paramter that isn't writable via sysfs!
247 #define kparam_block_sysfs_write(name) \
249 BUG_ON(!(__param_##name.perm & 0222)); \
250 __kernel_param_lock(); \
254 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
255 * @name: the name of the parameter
257 #define kparam_unblock_sysfs_write(name) \
259 BUG_ON(!(__param_##name.perm & 0222)); \
260 __kernel_param_unlock(); \
264 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
265 * @name: the name of the parameter
267 * This also blocks sysfs writes.
269 #define kparam_block_sysfs_read(name) \
271 BUG_ON(!(__param_##name.perm & 0444)); \
272 __kernel_param_lock(); \
276 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
277 * @name: the name of the parameter
279 #define kparam_unblock_sysfs_read(name) \
281 BUG_ON(!(__param_##name.perm & 0444)); \
282 __kernel_param_unlock(); \
286 extern void __kernel_param_lock(void);
287 extern void __kernel_param_unlock(void);
289 static inline void __kernel_param_lock(void)
292 static inline void __kernel_param_unlock(void)
299 * core_param - define a historical core kernel parameter.
300 * @name: the name of the cmdline and sysfs parameter (often the same as var)
302 * @type: the type of the parameter
303 * @perm: visibility in sysfs
305 * core_param is just like module_param(), but cannot be modular and
306 * doesn't add a prefix (such as "printk."). This is for compatibility
307 * with __setup(), and it makes sense as truly core parameters aren't
308 * tied to the particular file they're in.
310 #define core_param(name, var, type, perm) \
311 param_check_##type(name, &(var)); \
312 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0)
315 * core_param_unsafe - same as core_param but taints kernel
317 #define core_param_unsafe(name, var, type, perm) \
318 param_check_##type(name, &(var)); \
319 __module_param_call("", name, ¶m_ops_##type, &var, perm, \
320 -1, KERNEL_PARAM_FL_UNSAFE)
325 * module_param_string - a char array parameter
326 * @name: the name of the parameter
327 * @string: the string variable
328 * @len: the maximum length of the string, incl. terminator
329 * @perm: visibility in sysfs.
331 * This actually copies the string when it's set (unlike type charp).
332 * @len is usually just sizeof(string).
334 #define module_param_string(name, string, len, perm) \
335 static const struct kparam_string __param_string_##name \
337 __module_param_call(MODULE_PARAM_PREFIX, name, \
339 .str = &__param_string_##name, perm, -1, 0);\
340 __MODULE_PARM_TYPE(name, "string")
343 * parameq - checks if two parameter names match
344 * @name1: parameter name 1
345 * @name2: parameter name 2
347 * Returns true if the two parameter names are equal.
348 * Dashes (-) are considered equal to underscores (_).
350 extern bool parameq(const char *name1, const char *name2);
353 * parameqn - checks if two parameter names match
354 * @name1: parameter name 1
355 * @name2: parameter name 2
356 * @n: the length to compare
358 * Similar to parameq(), except it compares @n characters.
360 extern bool parameqn(const char *name1, const char *name2, size_t n);
362 /* Called on module insert or kernel boot */
363 extern char *parse_args(const char *name,
365 const struct kernel_param *params,
370 int (*unknown)(char *param, char *val,
371 const char *doing, void *arg));
373 /* Called by module remove. */
375 extern void destroy_params(const struct kernel_param *params, unsigned num);
377 static inline void destroy_params(const struct kernel_param *params,
381 #endif /* !CONFIG_SYSFS */
383 /* All the helper functions */
384 /* The macros to do compile-time type checking stolen from Jakub
385 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
386 #define __param_check(name, p, type) \
387 static inline type __always_unused *__check_##name(void) { return(p); }
389 extern struct kernel_param_ops param_ops_byte;
390 extern int param_set_byte(const char *val, const struct kernel_param *kp);
391 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
392 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
394 extern struct kernel_param_ops param_ops_short;
395 extern int param_set_short(const char *val, const struct kernel_param *kp);
396 extern int param_get_short(char *buffer, const struct kernel_param *kp);
397 #define param_check_short(name, p) __param_check(name, p, short)
399 extern struct kernel_param_ops param_ops_ushort;
400 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
401 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
402 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
404 extern struct kernel_param_ops param_ops_int;
405 extern int param_set_int(const char *val, const struct kernel_param *kp);
406 extern int param_get_int(char *buffer, const struct kernel_param *kp);
407 #define param_check_int(name, p) __param_check(name, p, int)
409 extern struct kernel_param_ops param_ops_uint;
410 extern int param_set_uint(const char *val, const struct kernel_param *kp);
411 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
412 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
414 extern struct kernel_param_ops param_ops_long;
415 extern int param_set_long(const char *val, const struct kernel_param *kp);
416 extern int param_get_long(char *buffer, const struct kernel_param *kp);
417 #define param_check_long(name, p) __param_check(name, p, long)
419 extern struct kernel_param_ops param_ops_ulong;
420 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
421 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
422 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
424 extern struct kernel_param_ops param_ops_ullong;
425 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
426 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
427 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
429 extern struct kernel_param_ops param_ops_charp;
430 extern int param_set_charp(const char *val, const struct kernel_param *kp);
431 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
432 #define param_check_charp(name, p) __param_check(name, p, char *)
434 /* We used to allow int as well as bool. We're taking that away! */
435 extern struct kernel_param_ops param_ops_bool;
436 extern int param_set_bool(const char *val, const struct kernel_param *kp);
437 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
438 #define param_check_bool(name, p) __param_check(name, p, bool)
440 extern struct kernel_param_ops param_ops_invbool;
441 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
442 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
443 #define param_check_invbool(name, p) __param_check(name, p, bool)
445 /* An int, which can only be set like a bool (though it shows as an int). */
446 extern struct kernel_param_ops param_ops_bint;
447 extern int param_set_bint(const char *val, const struct kernel_param *kp);
448 #define param_get_bint param_get_int
449 #define param_check_bint param_check_int
452 * module_param_array - a parameter which is an array of some type
453 * @name: the name of the array variable
454 * @type: the type, as per module_param()
455 * @nump: optional pointer filled in with the number written
456 * @perm: visibility in sysfs
458 * Input and output are as comma-separated values. Commas inside values
459 * don't work properly (eg. an array of charp).
461 * ARRAY_SIZE(@name) is used to determine the number of elements in the
462 * array, so the definition must be visible.
464 #define module_param_array(name, type, nump, perm) \
465 module_param_array_named(name, name, type, nump, perm)
468 * module_param_array_named - renamed parameter which is an array of some type
469 * @name: a valid C identifier which is the parameter name
470 * @array: the name of the array variable
471 * @type: the type, as per module_param()
472 * @nump: optional pointer filled in with the number written
473 * @perm: visibility in sysfs
475 * This exposes a different name than the actual variable name. See
476 * module_param_named() for why this might be necessary.
478 #define module_param_array_named(name, array, type, nump, perm) \
479 param_check_##type(name, &(array)[0]); \
480 static const struct kparam_array __param_arr_##name \
481 = { .max = ARRAY_SIZE(array), .num = nump, \
482 .ops = ¶m_ops_##type, \
483 .elemsize = sizeof(array[0]), .elem = array }; \
484 __module_param_call(MODULE_PARAM_PREFIX, name, \
486 .arr = &__param_arr_##name, \
488 __MODULE_PARM_TYPE(name, "array of " #type)
490 extern struct kernel_param_ops param_array_ops;
492 extern struct kernel_param_ops param_ops_string;
493 extern int param_set_copystring(const char *val, const struct kernel_param *);
494 extern int param_get_string(char *buffer, const struct kernel_param *kp);
496 /* for exporting parameters in /sys/module/.../parameters */
500 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
501 extern int module_param_sysfs_setup(struct module *mod,
502 const struct kernel_param *kparam,
503 unsigned int num_params);
505 extern void module_param_sysfs_remove(struct module *mod);
507 static inline int module_param_sysfs_setup(struct module *mod,
508 const struct kernel_param *kparam,
509 unsigned int num_params)
514 static inline void module_param_sysfs_remove(struct module *mod)
518 #endif /* _LINUX_MODULE_PARAMS_H */