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)
316 * module_param_string - a char array parameter
317 * @name: the name of the parameter
318 * @string: the string variable
319 * @len: the maximum length of the string, incl. terminator
320 * @perm: visibility in sysfs.
322 * This actually copies the string when it's set (unlike type charp).
323 * @len is usually just sizeof(string).
325 #define module_param_string(name, string, len, perm) \
326 static const struct kparam_string __param_string_##name \
328 __module_param_call(MODULE_PARAM_PREFIX, name, \
330 .str = &__param_string_##name, perm, -1, 0);\
331 __MODULE_PARM_TYPE(name, "string")
334 * parameq - checks if two parameter names match
335 * @name1: parameter name 1
336 * @name2: parameter name 2
338 * Returns true if the two parameter names are equal.
339 * Dashes (-) are considered equal to underscores (_).
341 extern bool parameq(const char *name1
, const char *name2
);
344 * parameqn - checks if two parameter names match
345 * @name1: parameter name 1
346 * @name2: parameter name 2
347 * @n: the length to compare
349 * Similar to parameq(), except it compares @n characters.
351 extern bool parameqn(const char *name1
, const char *name2
, size_t n
);
353 /* Called on module insert or kernel boot */
354 extern char *parse_args(const char *name
,
356 const struct kernel_param
*params
,
361 int (*unknown
)(char *param
, char *val
,
362 const char *doing
, void *arg
));
364 /* Called by module remove. */
366 extern void destroy_params(const struct kernel_param
*params
, unsigned num
);
368 static inline void destroy_params(const struct kernel_param
*params
,
372 #endif /* !CONFIG_SYSFS */
374 /* All the helper functions */
375 /* The macros to do compile-time type checking stolen from Jakub
376 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
377 #define __param_check(name, p, type) \
378 static inline type __always_unused *__check_##name(void) { return(p); }
380 extern struct kernel_param_ops param_ops_byte
;
381 extern int param_set_byte(const char *val
, const struct kernel_param
*kp
);
382 extern int param_get_byte(char *buffer
, const struct kernel_param
*kp
);
383 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
385 extern struct kernel_param_ops param_ops_short
;
386 extern int param_set_short(const char *val
, const struct kernel_param
*kp
);
387 extern int param_get_short(char *buffer
, const struct kernel_param
*kp
);
388 #define param_check_short(name, p) __param_check(name, p, short)
390 extern struct kernel_param_ops param_ops_ushort
;
391 extern int param_set_ushort(const char *val
, const struct kernel_param
*kp
);
392 extern int param_get_ushort(char *buffer
, const struct kernel_param
*kp
);
393 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
395 extern struct kernel_param_ops param_ops_int
;
396 extern int param_set_int(const char *val
, const struct kernel_param
*kp
);
397 extern int param_get_int(char *buffer
, const struct kernel_param
*kp
);
398 #define param_check_int(name, p) __param_check(name, p, int)
400 extern struct kernel_param_ops param_ops_uint
;
401 extern int param_set_uint(const char *val
, const struct kernel_param
*kp
);
402 extern int param_get_uint(char *buffer
, const struct kernel_param
*kp
);
403 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
405 extern struct kernel_param_ops param_ops_long
;
406 extern int param_set_long(const char *val
, const struct kernel_param
*kp
);
407 extern int param_get_long(char *buffer
, const struct kernel_param
*kp
);
408 #define param_check_long(name, p) __param_check(name, p, long)
410 extern struct kernel_param_ops param_ops_ulong
;
411 extern int param_set_ulong(const char *val
, const struct kernel_param
*kp
);
412 extern int param_get_ulong(char *buffer
, const struct kernel_param
*kp
);
413 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
415 extern struct kernel_param_ops param_ops_ullong
;
416 extern int param_set_ullong(const char *val
, const struct kernel_param
*kp
);
417 extern int param_get_ullong(char *buffer
, const struct kernel_param
*kp
);
418 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
420 extern struct kernel_param_ops param_ops_charp
;
421 extern int param_set_charp(const char *val
, const struct kernel_param
*kp
);
422 extern int param_get_charp(char *buffer
, const struct kernel_param
*kp
);
423 #define param_check_charp(name, p) __param_check(name, p, char *)
425 /* We used to allow int as well as bool. We're taking that away! */
426 extern struct kernel_param_ops param_ops_bool
;
427 extern int param_set_bool(const char *val
, const struct kernel_param
*kp
);
428 extern int param_get_bool(char *buffer
, const struct kernel_param
*kp
);
429 #define param_check_bool(name, p) __param_check(name, p, bool)
431 extern struct kernel_param_ops param_ops_invbool
;
432 extern int param_set_invbool(const char *val
, const struct kernel_param
*kp
);
433 extern int param_get_invbool(char *buffer
, const struct kernel_param
*kp
);
434 #define param_check_invbool(name, p) __param_check(name, p, bool)
436 /* An int, which can only be set like a bool (though it shows as an int). */
437 extern struct kernel_param_ops param_ops_bint
;
438 extern int param_set_bint(const char *val
, const struct kernel_param
*kp
);
439 #define param_get_bint param_get_int
440 #define param_check_bint param_check_int
443 * module_param_array - a parameter which is an array of some type
444 * @name: the name of the array variable
445 * @type: the type, as per module_param()
446 * @nump: optional pointer filled in with the number written
447 * @perm: visibility in sysfs
449 * Input and output are as comma-separated values. Commas inside values
450 * don't work properly (eg. an array of charp).
452 * ARRAY_SIZE(@name) is used to determine the number of elements in the
453 * array, so the definition must be visible.
455 #define module_param_array(name, type, nump, perm) \
456 module_param_array_named(name, name, type, nump, perm)
459 * module_param_array_named - renamed parameter which is an array of some type
460 * @name: a valid C identifier which is the parameter name
461 * @array: the name of the array variable
462 * @type: the type, as per module_param()
463 * @nump: optional pointer filled in with the number written
464 * @perm: visibility in sysfs
466 * This exposes a different name than the actual variable name. See
467 * module_param_named() for why this might be necessary.
469 #define module_param_array_named(name, array, type, nump, perm) \
470 param_check_##type(name, &(array)[0]); \
471 static const struct kparam_array __param_arr_##name \
472 = { .max = ARRAY_SIZE(array), .num = nump, \
473 .ops = ¶m_ops_##type, \
474 .elemsize = sizeof(array[0]), .elem = array }; \
475 __module_param_call(MODULE_PARAM_PREFIX, name, \
477 .arr = &__param_arr_##name, \
479 __MODULE_PARM_TYPE(name, "array of " #type)
481 extern struct kernel_param_ops param_array_ops
;
483 extern struct kernel_param_ops param_ops_string
;
484 extern int param_set_copystring(const char *val
, const struct kernel_param
*);
485 extern int param_get_string(char *buffer
, const struct kernel_param
*kp
);
487 /* for exporting parameters in /sys/module/.../parameters */
491 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
492 extern int module_param_sysfs_setup(struct module
*mod
,
493 const struct kernel_param
*kparam
,
494 unsigned int num_params
);
496 extern void module_param_sysfs_remove(struct module
*mod
);
498 static inline int module_param_sysfs_setup(struct module
*mod
,
499 const struct kernel_param
*kparam
,
500 unsigned int num_params
)
505 static inline void module_param_sysfs_remove(struct module
*mod
)
509 #endif /* _LINUX_MODULE_PARAMS_H */