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>
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
13 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
14 #endif
15
16 /* Chosen so that structs with an unsigned long line up. */
17 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
18
19 #define ___module_cat(a,b) __mod_ ## a ## b
20 #define __module_cat(a,b) ___module_cat(a,b)
21 #ifdef MODULE
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
26 #else /* !MODULE */
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__) {}
30 #endif
31 #define __MODULE_PARM_TYPE(name, _type) \
32 __MODULE_INFO(parmtype, name##type, #name ":" _type)
33
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)
38
39 struct kernel_param;
40
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);
48 };
49
50 struct kernel_param {
51 const char *name;
52 const struct kernel_param_ops *ops;
53 u16 perm;
54 s16 level;
55 union {
56 void *arg;
57 const struct kparam_string *str;
58 const struct kparam_array *arr;
59 };
60 };
61
62 /* Special one for strings we want to copy into */
63 struct kparam_string {
64 unsigned int maxlen;
65 char *string;
66 };
67
68 /* Special one for arrays */
69 struct kparam_array
70 {
71 unsigned int max;
72 unsigned int elemsize;
73 unsigned int *num;
74 const struct kernel_param_ops *ops;
75 void *elem;
76 };
77
78 /**
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.
83 *
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".
87 *
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).
92 *
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.
96 *
97 * Standard types are:
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).
102 */
103 #define module_param(name, type, perm) \
104 module_param_named(name, name, type, perm)
105
106 /**
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.
112 *
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.
116 */
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)
121
122 /**
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.
127 *
128 * The ops can have NULL set or get functions.
129 */
130 #define module_param_cb(name, ops, arg, perm) \
131 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1)
132
133 /**
134 * <level>_param_cb - general callback for a module/cmdline parameter
135 * to be evaluated before certain initcall level
136 * @name: a valid C identifier which is the parameter name.
137 * @ops: the set & get operations for this parameter.
138 * @perm: visibility in sysfs.
139 *
140 * The ops can have NULL set or get functions.
141 */
142 #define __level_param_cb(name, ops, arg, perm, level) \
143 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level)
144
145 #define core_param_cb(name, ops, arg, perm) \
146 __level_param_cb(name, ops, arg, perm, 1)
147
148 #define postcore_param_cb(name, ops, arg, perm) \
149 __level_param_cb(name, ops, arg, perm, 2)
150
151 #define arch_param_cb(name, ops, arg, perm) \
152 __level_param_cb(name, ops, arg, perm, 3)
153
154 #define subsys_param_cb(name, ops, arg, perm) \
155 __level_param_cb(name, ops, arg, perm, 4)
156
157 #define fs_param_cb(name, ops, arg, perm) \
158 __level_param_cb(name, ops, arg, perm, 5)
159
160 #define device_param_cb(name, ops, arg, perm) \
161 __level_param_cb(name, ops, arg, perm, 6)
162
163 #define late_param_cb(name, ops, arg, perm) \
164 __level_param_cb(name, ops, arg, perm, 7)
165
166 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
167 read-only sections (which is part of respective UNIX ABI on these
168 platforms). So 'const' makes no sense and even causes compile failures
169 with some compilers. */
170 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
171 #define __moduleparam_const
172 #else
173 #define __moduleparam_const const
174 #endif
175
176 /* This is the fundamental function for registering boot/module
177 parameters. */
178 #define __module_param_call(prefix, name, ops, arg, perm, level) \
179 /* Default value instead of permissions? */ \
180 static int __param_perm_check_##name __attribute__((unused)) = \
181 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
182 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
183 static const char __param_str_##name[] = prefix #name; \
184 static struct kernel_param __moduleparam_const __param_##name \
185 __used \
186 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
187 = { __param_str_##name, ops, perm, level, { arg } }
188
189 /* Obsolete - use module_param_cb() */
190 #define module_param_call(name, set, get, arg, perm) \
191 static struct kernel_param_ops __param_ops_##name = \
192 { (void *)set, (void *)get }; \
193 __module_param_call(MODULE_PARAM_PREFIX, \
194 name, &__param_ops_##name, arg, \
195 (perm) + sizeof(__check_old_set_param(set))*0, -1)
196
197 /* We don't get oldget: it's often a new-style param_get_uint, etc. */
198 static inline int
__check_old_set_param(int (* oldset)(const char *,struct kernel_param *))199 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
200 {
201 return 0;
202 }
203
204 /**
205 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
206 * @name: the name of the parameter
207 *
208 * There's no point blocking write on a paramter that isn't writable via sysfs!
209 */
210 #define kparam_block_sysfs_write(name) \
211 do { \
212 BUG_ON(!(__param_##name.perm & 0222)); \
213 __kernel_param_lock(); \
214 } while (0)
215
216 /**
217 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
218 * @name: the name of the parameter
219 */
220 #define kparam_unblock_sysfs_write(name) \
221 do { \
222 BUG_ON(!(__param_##name.perm & 0222)); \
223 __kernel_param_unlock(); \
224 } while (0)
225
226 /**
227 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
228 * @name: the name of the parameter
229 *
230 * This also blocks sysfs writes.
231 */
232 #define kparam_block_sysfs_read(name) \
233 do { \
234 BUG_ON(!(__param_##name.perm & 0444)); \
235 __kernel_param_lock(); \
236 } while (0)
237
238 /**
239 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
240 * @name: the name of the parameter
241 */
242 #define kparam_unblock_sysfs_read(name) \
243 do { \
244 BUG_ON(!(__param_##name.perm & 0444)); \
245 __kernel_param_unlock(); \
246 } while (0)
247
248 #ifdef CONFIG_SYSFS
249 extern void __kernel_param_lock(void);
250 extern void __kernel_param_unlock(void);
251 #else
__kernel_param_lock(void)252 static inline void __kernel_param_lock(void)
253 {
254 }
__kernel_param_unlock(void)255 static inline void __kernel_param_unlock(void)
256 {
257 }
258 #endif
259
260 #ifndef MODULE
261 /**
262 * core_param - define a historical core kernel parameter.
263 * @name: the name of the cmdline and sysfs parameter (often the same as var)
264 * @var: the variable
265 * @type: the type of the parameter
266 * @perm: visibility in sysfs
267 *
268 * core_param is just like module_param(), but cannot be modular and
269 * doesn't add a prefix (such as "printk."). This is for compatibility
270 * with __setup(), and it makes sense as truly core parameters aren't
271 * tied to the particular file they're in.
272 */
273 #define core_param(name, var, type, perm) \
274 param_check_##type(name, &(var)); \
275 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1)
276 #endif /* !MODULE */
277
278 /**
279 * module_param_string - a char array parameter
280 * @name: the name of the parameter
281 * @string: the string variable
282 * @len: the maximum length of the string, incl. terminator
283 * @perm: visibility in sysfs.
284 *
285 * This actually copies the string when it's set (unlike type charp).
286 * @len is usually just sizeof(string).
287 */
288 #define module_param_string(name, string, len, perm) \
289 static const struct kparam_string __param_string_##name \
290 = { len, string }; \
291 __module_param_call(MODULE_PARAM_PREFIX, name, \
292 ¶m_ops_string, \
293 .str = &__param_string_##name, perm, -1); \
294 __MODULE_PARM_TYPE(name, "string")
295
296 /**
297 * parameq - checks if two parameter names match
298 * @name1: parameter name 1
299 * @name2: parameter name 2
300 *
301 * Returns true if the two parameter names are equal.
302 * Dashes (-) are considered equal to underscores (_).
303 */
304 extern bool parameq(const char *name1, const char *name2);
305
306 /**
307 * parameqn - checks if two parameter names match
308 * @name1: parameter name 1
309 * @name2: parameter name 2
310 * @n: the length to compare
311 *
312 * Similar to parameq(), except it compares @n characters.
313 */
314 extern bool parameqn(const char *name1, const char *name2, size_t n);
315
316 /* Called on module insert or kernel boot */
317 extern int parse_args(const char *name,
318 char *args,
319 const struct kernel_param *params,
320 unsigned num,
321 s16 level_min,
322 s16 level_max,
323 int (*unknown)(char *param, char *val));
324
325 /* Called by module remove. */
326 #ifdef CONFIG_SYSFS
327 extern void destroy_params(const struct kernel_param *params, unsigned num);
328 #else
destroy_params(const struct kernel_param * params,unsigned num)329 static inline void destroy_params(const struct kernel_param *params,
330 unsigned num)
331 {
332 }
333 #endif /* !CONFIG_SYSFS */
334
335 /* All the helper functions */
336 /* The macros to do compile-time type checking stolen from Jakub
337 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
338 #define __param_check(name, p, type) \
339 static inline type *__check_##name(void) { return(p); }
340
341 extern struct kernel_param_ops param_ops_byte;
342 extern int param_set_byte(const char *val, const struct kernel_param *kp);
343 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
344 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
345
346 extern struct kernel_param_ops param_ops_short;
347 extern int param_set_short(const char *val, const struct kernel_param *kp);
348 extern int param_get_short(char *buffer, const struct kernel_param *kp);
349 #define param_check_short(name, p) __param_check(name, p, short)
350
351 extern struct kernel_param_ops param_ops_ushort;
352 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
353 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
354 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
355
356 extern struct kernel_param_ops param_ops_int;
357 extern int param_set_int(const char *val, const struct kernel_param *kp);
358 extern int param_get_int(char *buffer, const struct kernel_param *kp);
359 #define param_check_int(name, p) __param_check(name, p, int)
360
361 extern struct kernel_param_ops param_ops_uint;
362 extern int param_set_uint(const char *val, const struct kernel_param *kp);
363 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
364 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
365
366 extern struct kernel_param_ops param_ops_long;
367 extern int param_set_long(const char *val, const struct kernel_param *kp);
368 extern int param_get_long(char *buffer, const struct kernel_param *kp);
369 #define param_check_long(name, p) __param_check(name, p, long)
370
371 extern struct kernel_param_ops param_ops_ulong;
372 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
373 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
374 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
375
376 extern struct kernel_param_ops param_ops_charp;
377 extern int param_set_charp(const char *val, const struct kernel_param *kp);
378 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
379 #define param_check_charp(name, p) __param_check(name, p, char *)
380
381 /* We used to allow int as well as bool. We're taking that away! */
382 extern struct kernel_param_ops param_ops_bool;
383 extern int param_set_bool(const char *val, const struct kernel_param *kp);
384 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
385 #define param_check_bool(name, p) __param_check(name, p, bool)
386
387 extern struct kernel_param_ops param_ops_invbool;
388 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
389 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
390 #define param_check_invbool(name, p) __param_check(name, p, bool)
391
392 /* An int, which can only be set like a bool (though it shows as an int). */
393 extern struct kernel_param_ops param_ops_bint;
394 extern int param_set_bint(const char *val, const struct kernel_param *kp);
395 #define param_get_bint param_get_int
396 #define param_check_bint param_check_int
397
398 /**
399 * module_param_array - a parameter which is an array of some type
400 * @name: the name of the array variable
401 * @type: the type, as per module_param()
402 * @nump: optional pointer filled in with the number written
403 * @perm: visibility in sysfs
404 *
405 * Input and output are as comma-separated values. Commas inside values
406 * don't work properly (eg. an array of charp).
407 *
408 * ARRAY_SIZE(@name) is used to determine the number of elements in the
409 * array, so the definition must be visible.
410 */
411 #define module_param_array(name, type, nump, perm) \
412 module_param_array_named(name, name, type, nump, perm)
413
414 /**
415 * module_param_array_named - renamed parameter which is an array of some type
416 * @name: a valid C identifier which is the parameter name
417 * @array: the name of the array variable
418 * @type: the type, as per module_param()
419 * @nump: optional pointer filled in with the number written
420 * @perm: visibility in sysfs
421 *
422 * This exposes a different name than the actual variable name. See
423 * module_param_named() for why this might be necessary.
424 */
425 #define module_param_array_named(name, array, type, nump, perm) \
426 param_check_##type(name, &(array)[0]); \
427 static const struct kparam_array __param_arr_##name \
428 = { .max = ARRAY_SIZE(array), .num = nump, \
429 .ops = ¶m_ops_##type, \
430 .elemsize = sizeof(array[0]), .elem = array }; \
431 __module_param_call(MODULE_PARAM_PREFIX, name, \
432 ¶m_array_ops, \
433 .arr = &__param_arr_##name, \
434 perm, -1); \
435 __MODULE_PARM_TYPE(name, "array of " #type)
436
437 extern struct kernel_param_ops param_array_ops;
438
439 extern struct kernel_param_ops param_ops_string;
440 extern int param_set_copystring(const char *val, const struct kernel_param *);
441 extern int param_get_string(char *buffer, const struct kernel_param *kp);
442
443 /* for exporting parameters in /sys/parameters */
444
445 struct module;
446
447 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
448 extern int module_param_sysfs_setup(struct module *mod,
449 const struct kernel_param *kparam,
450 unsigned int num_params);
451
452 extern void module_param_sysfs_remove(struct module *mod);
453 #else
module_param_sysfs_setup(struct module * mod,const struct kernel_param * kparam,unsigned int num_params)454 static inline int module_param_sysfs_setup(struct module *mod,
455 const struct kernel_param *kparam,
456 unsigned int num_params)
457 {
458 return 0;
459 }
460
module_param_sysfs_remove(struct module * mod)461 static inline void module_param_sysfs_remove(struct module *mod)
462 { }
463 #endif
464
465 #endif /* _LINUX_MODULE_PARAMS_H */
466