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 /* Flag bits for kernel_param.flags */ 51 #define KPARAM_ISBOOL 2 52 53 struct kernel_param { 54 const char *name; 55 const struct kernel_param_ops *ops; 56 u16 perm; 57 u16 flags; 58 union { 59 void *arg; 60 const struct kparam_string *str; 61 const struct kparam_array *arr; 62 }; 63 }; 64 65 /* Special one for strings we want to copy into */ 66 struct kparam_string { 67 unsigned int maxlen; 68 char *string; 69 }; 70 71 /* Special one for arrays */ 72 struct kparam_array 73 { 74 unsigned int max; 75 unsigned int elemsize; 76 unsigned int *num; 77 const struct kernel_param_ops *ops; 78 void *elem; 79 }; 80 81 /** 82 * module_param - typesafe helper for a module/cmdline parameter 83 * @value: the variable to alter, and exposed parameter name. 84 * @type: the type of the parameter 85 * @perm: visibility in sysfs. 86 * 87 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 88 * ".") the kernel commandline parameter. Note that - is changed to _, so 89 * the user can use "foo-bar=1" even for variable "foo_bar". 90 * 91 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 92 * for world-readable, 0644 for root-writable, etc. Note that if it 93 * is writable, you may need to use kparam_block_sysfs_write() around 94 * accesses (esp. charp, which can be kfreed when it changes). 95 * 96 * The @type is simply pasted to refer to a param_ops_##type and a 97 * param_check_##type: for convenience many standard types are provided but 98 * you can create your own by defining those variables. 99 * 100 * Standard types are: 101 * byte, short, ushort, int, uint, long, ulong 102 * charp: a character pointer 103 * bool: a bool, values 0/1, y/n, Y/N. 104 * invbool: the above, only sense-reversed (N = true). 105 */ 106 #define module_param(name, type, perm) \ 107 module_param_named(name, name, type, perm) 108 109 /** 110 * module_param_named - typesafe helper for a renamed module/cmdline parameter 111 * @name: a valid C identifier which is the parameter name. 112 * @value: the actual lvalue to alter. 113 * @type: the type of the parameter 114 * @perm: visibility in sysfs. 115 * 116 * Usually it's a good idea to have variable names and user-exposed names the 117 * same, but that's harder if the variable must be non-static or is inside a 118 * structure. This allows exposure under a different name. 119 */ 120 #define module_param_named(name, value, type, perm) \ 121 param_check_##type(name, &(value)); \ 122 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 123 __MODULE_PARM_TYPE(name, #type) 124 125 /** 126 * module_param_cb - general callback for a module/cmdline parameter 127 * @name: a valid C identifier which is the parameter name. 128 * @ops: the set & get operations for this parameter. 129 * @perm: visibility in sysfs. 130 * 131 * The ops can have NULL set or get functions. 132 */ 133 #define module_param_cb(name, ops, arg, perm) \ 134 __module_param_call(MODULE_PARAM_PREFIX, \ 135 name, ops, arg, __same_type((arg), bool *), perm) 136 137 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 138 read-only sections (which is part of respective UNIX ABI on these 139 platforms). So 'const' makes no sense and even causes compile failures 140 with some compilers. */ 141 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 142 #define __moduleparam_const 143 #else 144 #define __moduleparam_const const 145 #endif 146 147 /* This is the fundamental function for registering boot/module 148 parameters. */ 149 #define __module_param_call(prefix, name, ops, arg, isbool, perm) \ 150 /* Default value instead of permissions? */ \ 151 static int __param_perm_check_##name __attribute__((unused)) = \ 152 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ 153 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \ 154 static const char __param_str_##name[] = prefix #name; \ 155 static struct kernel_param __moduleparam_const __param_##name \ 156 __used \ 157 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 158 = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \ 159 { arg } } 160 161 /* Obsolete - use module_param_cb() */ 162 #define module_param_call(name, set, get, arg, perm) \ 163 static struct kernel_param_ops __param_ops_##name = \ 164 { (void *)set, (void *)get }; \ 165 __module_param_call(MODULE_PARAM_PREFIX, \ 166 name, &__param_ops_##name, arg, \ 167 __same_type(arg, bool *), \ 168 (perm) + sizeof(__check_old_set_param(set))*0) 169 170 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 171 static inline int 172 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 173 { 174 return 0; 175 } 176 177 /** 178 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 179 * @name: the name of the parameter 180 * 181 * There's no point blocking write on a paramter that isn't writable via sysfs! 182 */ 183 #define kparam_block_sysfs_write(name) \ 184 do { \ 185 BUG_ON(!(__param_##name.perm & 0222)); \ 186 __kernel_param_lock(); \ 187 } while (0) 188 189 /** 190 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 191 * @name: the name of the parameter 192 */ 193 #define kparam_unblock_sysfs_write(name) \ 194 do { \ 195 BUG_ON(!(__param_##name.perm & 0222)); \ 196 __kernel_param_unlock(); \ 197 } while (0) 198 199 /** 200 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 201 * @name: the name of the parameter 202 * 203 * This also blocks sysfs writes. 204 */ 205 #define kparam_block_sysfs_read(name) \ 206 do { \ 207 BUG_ON(!(__param_##name.perm & 0444)); \ 208 __kernel_param_lock(); \ 209 } while (0) 210 211 /** 212 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 213 * @name: the name of the parameter 214 */ 215 #define kparam_unblock_sysfs_read(name) \ 216 do { \ 217 BUG_ON(!(__param_##name.perm & 0444)); \ 218 __kernel_param_unlock(); \ 219 } while (0) 220 221 #ifdef CONFIG_SYSFS 222 extern void __kernel_param_lock(void); 223 extern void __kernel_param_unlock(void); 224 #else 225 static inline void __kernel_param_lock(void) 226 { 227 } 228 static inline void __kernel_param_unlock(void) 229 { 230 } 231 #endif 232 233 #ifndef MODULE 234 /** 235 * core_param - define a historical core kernel parameter. 236 * @name: the name of the cmdline and sysfs parameter (often the same as var) 237 * @var: the variable 238 * @type: the type of the parameter 239 * @perm: visibility in sysfs 240 * 241 * core_param is just like module_param(), but cannot be modular and 242 * doesn't add a prefix (such as "printk."). This is for compatibility 243 * with __setup(), and it makes sense as truly core parameters aren't 244 * tied to the particular file they're in. 245 */ 246 #define core_param(name, var, type, perm) \ 247 param_check_##type(name, &(var)); \ 248 __module_param_call("", name, ¶m_ops_##type, \ 249 &var, __same_type(var, bool), perm) 250 #endif /* !MODULE */ 251 252 /** 253 * module_param_string - a char array parameter 254 * @name: the name of the parameter 255 * @string: the string variable 256 * @len: the maximum length of the string, incl. terminator 257 * @perm: visibility in sysfs. 258 * 259 * This actually copies the string when it's set (unlike type charp). 260 * @len is usually just sizeof(string). 261 */ 262 #define module_param_string(name, string, len, perm) \ 263 static const struct kparam_string __param_string_##name \ 264 = { len, string }; \ 265 __module_param_call(MODULE_PARAM_PREFIX, name, \ 266 ¶m_ops_string, \ 267 .str = &__param_string_##name, 0, perm); \ 268 __MODULE_PARM_TYPE(name, "string") 269 270 /** 271 * parameq - checks if two parameter names match 272 * @name1: parameter name 1 273 * @name2: parameter name 2 274 * 275 * Returns true if the two parameter names are equal. 276 * Dashes (-) are considered equal to underscores (_). 277 */ 278 extern bool parameq(const char *name1, const char *name2); 279 280 /** 281 * parameqn - checks if two parameter names match 282 * @name1: parameter name 1 283 * @name2: parameter name 2 284 * @n: the length to compare 285 * 286 * Similar to parameq(), except it compares @n characters. 287 */ 288 extern bool parameqn(const char *name1, const char *name2, size_t n); 289 290 /* Called on module insert or kernel boot */ 291 extern int parse_args(const char *name, 292 char *args, 293 const struct kernel_param *params, 294 unsigned num, 295 int (*unknown)(char *param, char *val)); 296 297 /* Called by module remove. */ 298 #ifdef CONFIG_SYSFS 299 extern void destroy_params(const struct kernel_param *params, unsigned num); 300 #else 301 static inline void destroy_params(const struct kernel_param *params, 302 unsigned num) 303 { 304 } 305 #endif /* !CONFIG_SYSFS */ 306 307 /* All the helper functions */ 308 /* The macros to do compile-time type checking stolen from Jakub 309 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 310 #define __param_check(name, p, type) \ 311 static inline type *__check_##name(void) { return(p); } 312 313 extern struct kernel_param_ops param_ops_byte; 314 extern int param_set_byte(const char *val, const struct kernel_param *kp); 315 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 316 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 317 318 extern struct kernel_param_ops param_ops_short; 319 extern int param_set_short(const char *val, const struct kernel_param *kp); 320 extern int param_get_short(char *buffer, const struct kernel_param *kp); 321 #define param_check_short(name, p) __param_check(name, p, short) 322 323 extern struct kernel_param_ops param_ops_ushort; 324 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 325 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 326 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 327 328 extern struct kernel_param_ops param_ops_int; 329 extern int param_set_int(const char *val, const struct kernel_param *kp); 330 extern int param_get_int(char *buffer, const struct kernel_param *kp); 331 #define param_check_int(name, p) __param_check(name, p, int) 332 333 extern struct kernel_param_ops param_ops_uint; 334 extern int param_set_uint(const char *val, const struct kernel_param *kp); 335 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 336 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 337 338 extern struct kernel_param_ops param_ops_long; 339 extern int param_set_long(const char *val, const struct kernel_param *kp); 340 extern int param_get_long(char *buffer, const struct kernel_param *kp); 341 #define param_check_long(name, p) __param_check(name, p, long) 342 343 extern struct kernel_param_ops param_ops_ulong; 344 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 345 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 346 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 347 348 extern struct kernel_param_ops param_ops_charp; 349 extern int param_set_charp(const char *val, const struct kernel_param *kp); 350 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 351 #define param_check_charp(name, p) __param_check(name, p, char *) 352 353 /* We used to allow int as well as bool. We're taking that away! */ 354 extern struct kernel_param_ops param_ops_bool; 355 extern int param_set_bool(const char *val, const struct kernel_param *kp); 356 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 357 #define param_check_bool(name, p) __param_check(name, p, bool) 358 359 extern struct kernel_param_ops param_ops_invbool; 360 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 361 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 362 #define param_check_invbool(name, p) __param_check(name, p, bool) 363 364 /* An int, which can only be set like a bool (though it shows as an int). */ 365 extern struct kernel_param_ops param_ops_bint; 366 extern int param_set_bint(const char *val, const struct kernel_param *kp); 367 #define param_get_bint param_get_int 368 #define param_check_bint param_check_int 369 370 /** 371 * module_param_array - a parameter which is an array of some type 372 * @name: the name of the array variable 373 * @type: the type, as per module_param() 374 * @nump: optional pointer filled in with the number written 375 * @perm: visibility in sysfs 376 * 377 * Input and output are as comma-separated values. Commas inside values 378 * don't work properly (eg. an array of charp). 379 * 380 * ARRAY_SIZE(@name) is used to determine the number of elements in the 381 * array, so the definition must be visible. 382 */ 383 #define module_param_array(name, type, nump, perm) \ 384 module_param_array_named(name, name, type, nump, perm) 385 386 /** 387 * module_param_array_named - renamed parameter which is an array of some type 388 * @name: a valid C identifier which is the parameter name 389 * @array: the name of the array variable 390 * @type: the type, as per module_param() 391 * @nump: optional pointer filled in with the number written 392 * @perm: visibility in sysfs 393 * 394 * This exposes a different name than the actual variable name. See 395 * module_param_named() for why this might be necessary. 396 */ 397 #define module_param_array_named(name, array, type, nump, perm) \ 398 param_check_##type(name, &(array)[0]); \ 399 static const struct kparam_array __param_arr_##name \ 400 = { .max = ARRAY_SIZE(array), .num = nump, \ 401 .ops = ¶m_ops_##type, \ 402 .elemsize = sizeof(array[0]), .elem = array }; \ 403 __module_param_call(MODULE_PARAM_PREFIX, name, \ 404 ¶m_array_ops, \ 405 .arr = &__param_arr_##name, \ 406 __same_type(array[0], bool), perm); \ 407 __MODULE_PARM_TYPE(name, "array of " #type) 408 409 extern struct kernel_param_ops param_array_ops; 410 411 extern struct kernel_param_ops param_ops_string; 412 extern int param_set_copystring(const char *val, const struct kernel_param *); 413 extern int param_get_string(char *buffer, const struct kernel_param *kp); 414 415 /* for exporting parameters in /sys/parameters */ 416 417 struct module; 418 419 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 420 extern int module_param_sysfs_setup(struct module *mod, 421 const struct kernel_param *kparam, 422 unsigned int num_params); 423 424 extern void module_param_sysfs_remove(struct module *mod); 425 #else 426 static inline int module_param_sysfs_setup(struct module *mod, 427 const struct kernel_param *kparam, 428 unsigned int num_params) 429 { 430 return 0; 431 } 432 433 static inline void module_param_sysfs_remove(struct module *mod) 434 { } 435 #endif 436 437 #endif /* _LINUX_MODULE_PARAMS_H */ 438