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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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
Sam Ravnborg367cb702006-01-06 21:17:50 +010013#define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#endif
15
Rusty Russell730b69d2008-10-22 10:00:22 -050016/* Chosen so that structs with an unsigned long line up. */
17#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
18
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#ifdef MODULE
20#define ___module_cat(a,b) __mod_ ## a ## b
21#define __module_cat(a,b) ___module_cat(a,b)
22#define __MODULE_INFO(tag, name, info) \
23static const char __module_cat(name,__LINE__)[] \
Adrian Bunk3ff6eec2008-01-24 22:16:20 +010024 __used \
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 __attribute__((section(".modinfo"),unused)) = __stringify(tag) "=" info
26#else /* !MODULE */
27#define __MODULE_INFO(tag, name, info)
28#endif
29#define __MODULE_PARM_TYPE(name, _type) \
30 __MODULE_INFO(parmtype, name##type, #name ":" _type)
31
32struct kernel_param;
33
Rusty Russell9bbb9e52010-08-11 23:04:12 -060034struct kernel_param_ops {
35 /* Returns 0, or -errno. arg is in kp->arg. */
36 int (*set)(const char *val, const struct kernel_param *kp);
37 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
38 int (*get)(char *buffer, const struct kernel_param *kp);
Rusty Russelle6df34a2010-08-11 23:04:17 -060039 /* Optional function to free kp->arg when module unloaded. */
40 void (*free)(void *arg);
Rusty Russell9bbb9e52010-08-11 23:04:12 -060041};
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Rusty Russell45fcc702009-06-12 21:46:56 -060043/* Flag bits for kernel_param.flags */
Rusty Russellfddd5202009-06-12 21:46:57 -060044#define KPARAM_ISBOOL 2
Rusty Russell45fcc702009-06-12 21:46:56 -060045
Linus Torvalds1da177e2005-04-16 15:20:36 -070046struct kernel_param {
47 const char *name;
Rusty Russell9bbb9e52010-08-11 23:04:12 -060048 const struct kernel_param_ops *ops;
Rusty Russell45fcc702009-06-12 21:46:56 -060049 u16 perm;
50 u16 flags;
Jan Beulich22e48ea2007-10-16 23:29:34 -070051 union {
52 void *arg;
53 const struct kparam_string *str;
54 const struct kparam_array *arr;
55 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070056};
57
58/* Special one for strings we want to copy into */
59struct kparam_string {
60 unsigned int maxlen;
61 char *string;
62};
63
64/* Special one for arrays */
65struct kparam_array
66{
67 unsigned int max;
68 unsigned int *num;
Rusty Russell9bbb9e52010-08-11 23:04:12 -060069 const struct kernel_param_ops *ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 unsigned int elemsize;
71 void *elem;
72};
73
Rusty Russell546970b2010-08-11 23:04:20 -060074/**
75 * module_param - typesafe helper for a module/cmdline parameter
76 * @value: the variable to alter, and exposed parameter name.
77 * @type: the type of the parameter
78 * @perm: visibility in sysfs.
79 *
80 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
81 * ".") the kernel commandline parameter. Note that - is changed to _, so
82 * the user can use "foo-bar=1" even for variable "foo_bar".
83 *
84 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
85 * for world-readable, 0644 for root-writable, etc. Note that if it
86 * is writable, you may need to use kparam_block_sysfs_write() around
87 * accesses (esp. charp, which can be kfreed when it changes).
88 *
89 * The @type is simply pasted to refer to a param_ops_##type and a
90 * param_check_##type: for convenience many standard types are provided but
91 * you can create your own by defining those variables.
92 *
93 * Standard types are:
94 * byte, short, ushort, int, uint, long, ulong
95 * charp: a character pointer
96 * bool: a bool, values 0/1, y/n, Y/N.
97 * invbool: the above, only sense-reversed (N = true).
98 */
99#define module_param(name, type, perm) \
100 module_param_named(name, name, type, perm)
101
102/**
103 * module_param_named - typesafe helper for a renamed module/cmdline parameter
104 * @name: a valid C identifier which is the parameter name.
105 * @value: the actual lvalue to alter.
106 * @type: the type of the parameter
107 * @perm: visibility in sysfs.
108 *
109 * Usually it's a good idea to have variable names and user-exposed names the
110 * same, but that's harder if the variable must be non-static or is inside a
111 * structure. This allows exposure under a different name.
112 */
113#define module_param_named(name, value, type, perm) \
114 param_check_##type(name, &(value)); \
115 module_param_cb(name, &param_ops_##type, &value, perm); \
116 __MODULE_PARM_TYPE(name, #type)
117
118/**
119 * module_param_cb - general callback for a module/cmdline parameter
120 * @name: a valid C identifier which is the parameter name.
121 * @ops: the set & get operations for this parameter.
122 * @perm: visibility in sysfs.
123 *
124 * The ops can have NULL set or get functions.
125 */
126#define module_param_cb(name, ops, arg, perm) \
127 __module_param_call(MODULE_PARAM_PREFIX, \
Rusty Russella6de51b2010-08-11 23:04:40 -0600128 name, ops, arg, __same_type((arg), bool *), perm)
Rusty Russell546970b2010-08-11 23:04:20 -0600129
Ivan Kokshaysky91d35dd2008-02-13 15:03:26 -0800130/* On alpha, ia64 and ppc64 relocations to global data cannot go into
131 read-only sections (which is part of respective UNIX ABI on these
132 platforms). So 'const' makes no sense and even causes compile failures
133 with some compilers. */
134#if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
135#define __moduleparam_const
136#else
137#define __moduleparam_const const
138#endif
139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140/* This is the fundamental function for registering boot/module
Rusty Russell546970b2010-08-11 23:04:20 -0600141 parameters. */
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600142#define __module_param_call(prefix, name, ops, arg, isbool, perm) \
Alexey Dobriyan9774a1f2006-12-06 20:36:56 -0800143 /* Default value instead of permissions? */ \
144 static int __param_perm_check_##name __attribute__((unused)) = \
Rusty Russell730b69d2008-10-22 10:00:22 -0500145 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
146 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
Jan Beulich22e48ea2007-10-16 23:29:34 -0700147 static const char __param_str_##name[] = prefix #name; \
Ivan Kokshaysky91d35dd2008-02-13 15:03:26 -0800148 static struct kernel_param __moduleparam_const __param_##name \
Adrian Bunk3ff6eec2008-01-24 22:16:20 +0100149 __used \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600151 = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \
152 { arg } }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600154/* Obsolete - use module_param_cb() */
155#define module_param_call(name, set, get, arg, perm) \
156 static struct kernel_param_ops __param_ops_##name = \
157 { (void *)set, (void *)get }; \
158 __module_param_call(MODULE_PARAM_PREFIX, \
159 name, &__param_ops_##name, arg, \
Rusty Russella6de51b2010-08-11 23:04:40 -0600160 __same_type(arg, bool *), \
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600161 (perm) + sizeof(__check_old_set_param(set))*0)
162
163/* We don't get oldget: it's often a new-style param_get_uint, etc. */
164static inline int
165__check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
166{
167 return 0;
168}
169
Rusty Russell907b29e2010-08-11 23:04:19 -0600170/**
171 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
172 * @name: the name of the parameter
173 *
174 * There's no point blocking write on a paramter that isn't writable via sysfs!
175 */
176#define kparam_block_sysfs_write(name) \
177 do { \
178 BUG_ON(!(__param_##name.perm & 0222)); \
179 __kernel_param_lock(); \
180 } while (0)
181
182/**
183 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
184 * @name: the name of the parameter
185 */
186#define kparam_unblock_sysfs_write(name) \
187 do { \
188 BUG_ON(!(__param_##name.perm & 0222)); \
189 __kernel_param_unlock(); \
190 } while (0)
191
192/**
193 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
194 * @name: the name of the parameter
195 *
196 * This also blocks sysfs writes.
197 */
198#define kparam_block_sysfs_read(name) \
199 do { \
200 BUG_ON(!(__param_##name.perm & 0444)); \
201 __kernel_param_lock(); \
202 } while (0)
203
204/**
205 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
206 * @name: the name of the parameter
207 */
208#define kparam_unblock_sysfs_read(name) \
209 do { \
210 BUG_ON(!(__param_##name.perm & 0444)); \
211 __kernel_param_unlock(); \
212 } while (0)
213
214#ifdef CONFIG_SYSFS
215extern void __kernel_param_lock(void);
216extern void __kernel_param_unlock(void);
217#else
218static inline void __kernel_param_lock(void)
219{
220}
221static inline void __kernel_param_unlock(void)
222{
223}
224#endif
225
Rusty Russell67e67ce2008-10-22 10:00:23 -0500226#ifndef MODULE
227/**
228 * core_param - define a historical core kernel parameter.
229 * @name: the name of the cmdline and sysfs parameter (often the same as var)
230 * @var: the variable
Rusty Russell546970b2010-08-11 23:04:20 -0600231 * @type: the type of the parameter
Rusty Russell67e67ce2008-10-22 10:00:23 -0500232 * @perm: visibility in sysfs
233 *
234 * core_param is just like module_param(), but cannot be modular and
235 * doesn't add a prefix (such as "printk."). This is for compatibility
236 * with __setup(), and it makes sense as truly core parameters aren't
237 * tied to the particular file they're in.
238 */
239#define core_param(name, var, type, perm) \
240 param_check_##type(name, &(var)); \
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600241 __module_param_call("", name, &param_ops_##type, \
Rusty Russellfddd5202009-06-12 21:46:57 -0600242 &var, __same_type(var, bool), perm)
Rusty Russell67e67ce2008-10-22 10:00:23 -0500243#endif /* !MODULE */
244
Rusty Russell546970b2010-08-11 23:04:20 -0600245/**
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.
251 *
252 * This actually copies the string when it's set (unlike type charp).
253 * @len is usually just sizeof(string).
254 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255#define module_param_string(name, string, len, perm) \
Jan Beulich22e48ea2007-10-16 23:29:34 -0700256 static const struct kparam_string __param_string_##name \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 = { len, string }; \
Rusty Russellfddd5202009-06-12 21:46:57 -0600258 __module_param_call(MODULE_PARAM_PREFIX, name, \
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600259 &param_ops_string, \
Rusty Russellfddd5202009-06-12 21:46:57 -0600260 .str = &__param_string_##name, 0, perm); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 __MODULE_PARM_TYPE(name, "string")
262
263/* Called on module insert or kernel boot */
264extern int parse_args(const char *name,
265 char *args,
Rusty Russell914dcaa2010-08-11 23:04:18 -0600266 const struct kernel_param *params,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 unsigned num,
268 int (*unknown)(char *param, char *val));
269
Rusty Russelle180a6b2009-03-31 13:05:29 -0600270/* Called by module remove. */
271#ifdef CONFIG_SYSFS
272extern void destroy_params(const struct kernel_param *params, unsigned num);
273#else
274static inline void destroy_params(const struct kernel_param *params,
275 unsigned num)
276{
277}
278#endif /* !CONFIG_SYSFS */
279
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280/* All the helper functions */
281/* The macros to do compile-time type checking stolen from Jakub
282 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
283#define __param_check(name, p, type) \
284 static inline type *__check_##name(void) { return(p); }
285
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600286extern struct kernel_param_ops param_ops_byte;
287extern int param_set_byte(const char *val, const struct kernel_param *kp);
288extern int param_get_byte(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289#define param_check_byte(name, p) __param_check(name, p, unsigned char)
290
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600291extern struct kernel_param_ops param_ops_short;
292extern int param_set_short(const char *val, const struct kernel_param *kp);
293extern int param_get_short(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294#define param_check_short(name, p) __param_check(name, p, short)
295
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600296extern struct kernel_param_ops param_ops_ushort;
297extern int param_set_ushort(const char *val, const struct kernel_param *kp);
298extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299#define param_check_ushort(name, p) __param_check(name, p, unsigned short)
300
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600301extern struct kernel_param_ops param_ops_int;
302extern int param_set_int(const char *val, const struct kernel_param *kp);
303extern int param_get_int(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304#define param_check_int(name, p) __param_check(name, p, int)
305
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600306extern struct kernel_param_ops param_ops_uint;
307extern int param_set_uint(const char *val, const struct kernel_param *kp);
308extern int param_get_uint(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309#define param_check_uint(name, p) __param_check(name, p, unsigned int)
310
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600311extern struct kernel_param_ops param_ops_long;
312extern int param_set_long(const char *val, const struct kernel_param *kp);
313extern int param_get_long(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314#define param_check_long(name, p) __param_check(name, p, long)
315
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600316extern struct kernel_param_ops param_ops_ulong;
317extern int param_set_ulong(const char *val, const struct kernel_param *kp);
318extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319#define param_check_ulong(name, p) __param_check(name, p, unsigned long)
320
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600321extern struct kernel_param_ops param_ops_charp;
322extern int param_set_charp(const char *val, const struct kernel_param *kp);
323extern int param_get_charp(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324#define param_check_charp(name, p) __param_check(name, p, char *)
325
Rusty Russellfddd5202009-06-12 21:46:57 -0600326/* For historical reasons "bool" parameters can be (unsigned) "int". */
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600327extern struct kernel_param_ops param_ops_bool;
328extern int param_set_bool(const char *val, const struct kernel_param *kp);
329extern int param_get_bool(char *buffer, const struct kernel_param *kp);
Rusty Russellfddd5202009-06-12 21:46:57 -0600330#define param_check_bool(name, p) \
331 static inline void __check_##name(void) \
332 { \
Rusty Russella6de51b2010-08-11 23:04:40 -0600333 BUILD_BUG_ON(!__same_type((p), bool *) && \
334 !__same_type((p), unsigned int *) && \
335 !__same_type((p), int *)); \
Rusty Russellfddd5202009-06-12 21:46:57 -0600336 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600338extern struct kernel_param_ops param_ops_invbool;
339extern int param_set_invbool(const char *val, const struct kernel_param *kp);
340extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
Rusty Russell9a71af22009-06-12 21:46:53 -0600341#define param_check_invbool(name, p) __param_check(name, p, bool)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
Rusty Russell546970b2010-08-11 23:04:20 -0600343/**
344 * module_param_array - a parameter which is an array of some type
345 * @name: the name of the array variable
346 * @type: the type, as per module_param()
347 * @nump: optional pointer filled in with the number written
348 * @perm: visibility in sysfs
349 *
350 * Input and output are as comma-separated values. Commas inside values
351 * don't work properly (eg. an array of charp).
352 *
353 * ARRAY_SIZE(@name) is used to determine the number of elements in the
354 * array, so the definition must be visible.
355 */
356#define module_param_array(name, type, nump, perm) \
357 module_param_array_named(name, name, type, nump, perm)
358
359/**
360 * module_param_array_named - renamed parameter which is an array of some type
361 * @name: a valid C identifier which is the parameter name
362 * @array: the name of the array variable
363 * @type: the type, as per module_param()
364 * @nump: optional pointer filled in with the number written
365 * @perm: visibility in sysfs
366 *
367 * This exposes a different name than the actual variable name. See
368 * module_param_named() for why this might be necessary.
369 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370#define module_param_array_named(name, array, type, nump, perm) \
Jan Beulich22e48ea2007-10-16 23:29:34 -0700371 static const struct kparam_array __param_arr_##name \
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600372 = { ARRAY_SIZE(array), nump, &param_ops_##type, \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 sizeof(array[0]), array }; \
Rusty Russellfddd5202009-06-12 21:46:57 -0600374 __module_param_call(MODULE_PARAM_PREFIX, name, \
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600375 &param_array_ops, \
Rusty Russellfddd5202009-06-12 21:46:57 -0600376 .arr = &__param_arr_##name, \
377 __same_type(array[0], bool), perm); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 __MODULE_PARM_TYPE(name, "array of " #type)
379
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600380extern struct kernel_param_ops param_array_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600382extern struct kernel_param_ops param_ops_string;
383extern int param_set_copystring(const char *val, const struct kernel_param *);
384extern int param_get_string(char *buffer, const struct kernel_param *kp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386/* for exporting parameters in /sys/parameters */
387
388struct module;
389
Randy Dunlapef665c12007-02-13 15:19:06 -0800390#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391extern int module_param_sysfs_setup(struct module *mod,
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600392 const struct kernel_param *kparam,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 unsigned int num_params);
394
395extern void module_param_sysfs_remove(struct module *mod);
Randy Dunlapef665c12007-02-13 15:19:06 -0800396#else
397static inline int module_param_sysfs_setup(struct module *mod,
Rusty Russell9bbb9e52010-08-11 23:04:12 -0600398 const struct kernel_param *kparam,
Randy Dunlapef665c12007-02-13 15:19:06 -0800399 unsigned int num_params)
400{
401 return 0;
402}
403
404static inline void module_param_sysfs_remove(struct module *mod)
405{ }
406#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408#endif /* _LINUX_MODULE_PARAMS_H */