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 #ifdef MODULE 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 24 #else /* !MODULE */ 25 /* This struct is here for syntactic coherency, it is not used */ 26 #define __MODULE_INFO(tag, name, info) \ 27 struct __UNIQUE_ID(name) {} 28 #endif 29 #define __MODULE_PARM_TYPE(name, _type) \ 30 __MODULE_INFO(parmtype, name##type, #name ":" _type) 31 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) 36 37 struct kernel_param; 38 39 struct kernel_param_ops { 40 /* Returns 0, or -errno. arg is in kp->arg. */ 41 int (*set)(const char *val, const struct kernel_param *kp); 42 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ 43 int (*get)(char *buffer, const struct kernel_param *kp); 44 /* Optional function to free kp->arg when module unloaded. */ 45 void (*free)(void *arg); 46 }; 47 48 struct kernel_param { 49 const char *name; 50 const struct kernel_param_ops *ops; 51 u16 perm; 52 s16 level; 53 union { 54 void *arg; 55 const struct kparam_string *str; 56 const struct kparam_array *arr; 57 }; 58 }; 59 60 /* Special one for strings we want to copy into */ 61 struct kparam_string { 62 unsigned int maxlen; 63 char *string; 64 }; 65 66 /* Special one for arrays */ 67 struct kparam_array 68 { 69 unsigned int max; 70 unsigned int elemsize; 71 unsigned int *num; 72 const struct kernel_param_ops *ops; 73 void *elem; 74 }; 75 76 /** 77 * module_param - typesafe helper for a module/cmdline parameter 78 * @value: the variable to alter, and exposed parameter name. 79 * @type: the type of the parameter 80 * @perm: visibility in sysfs. 81 * 82 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 83 * ".") the kernel commandline parameter. Note that - is changed to _, so 84 * the user can use "foo-bar=1" even for variable "foo_bar". 85 * 86 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 87 * for world-readable, 0644 for root-writable, etc. Note that if it 88 * is writable, you may need to use kparam_block_sysfs_write() around 89 * accesses (esp. charp, which can be kfreed when it changes). 90 * 91 * The @type is simply pasted to refer to a param_ops_##type and a 92 * param_check_##type: for convenience many standard types are provided but 93 * you can create your own by defining those variables. 94 * 95 * Standard types are: 96 * byte, short, ushort, int, uint, long, ulong 97 * charp: a character pointer 98 * bool: a bool, values 0/1, y/n, Y/N. 99 * invbool: the above, only sense-reversed (N = true). 100 */ 101 #define module_param(name, type, perm) \ 102 module_param_named(name, name, type, perm) 103 104 /** 105 * module_param_named - typesafe helper for a renamed module/cmdline parameter 106 * @name: a valid C identifier which is the parameter name. 107 * @value: the actual lvalue to alter. 108 * @type: the type of the parameter 109 * @perm: visibility in sysfs. 110 * 111 * Usually it's a good idea to have variable names and user-exposed names the 112 * same, but that's harder if the variable must be non-static or is inside a 113 * structure. This allows exposure under a different name. 114 */ 115 #define module_param_named(name, value, type, perm) \ 116 param_check_##type(name, &(value)); \ 117 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 118 __MODULE_PARM_TYPE(name, #type) 119 120 /** 121 * module_param_cb - general callback for a module/cmdline parameter 122 * @name: a valid C identifier which is the parameter name. 123 * @ops: the set & get operations for this parameter. 124 * @perm: visibility in sysfs. 125 * 126 * The ops can have NULL set or get functions. 127 */ 128 #define module_param_cb(name, ops, arg, perm) \ 129 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1) 130 131 /** 132 * <level>_param_cb - general callback for a module/cmdline parameter 133 * to be evaluated before certain initcall level 134 * @name: a valid C identifier which is the parameter name. 135 * @ops: the set & get operations for this parameter. 136 * @perm: visibility in sysfs. 137 * 138 * The ops can have NULL set or get functions. 139 */ 140 #define __level_param_cb(name, ops, arg, perm, level) \ 141 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level) 142 143 #define core_param_cb(name, ops, arg, perm) \ 144 __level_param_cb(name, ops, arg, perm, 1) 145 146 #define postcore_param_cb(name, ops, arg, perm) \ 147 __level_param_cb(name, ops, arg, perm, 2) 148 149 #define arch_param_cb(name, ops, arg, perm) \ 150 __level_param_cb(name, ops, arg, perm, 3) 151 152 #define subsys_param_cb(name, ops, arg, perm) \ 153 __level_param_cb(name, ops, arg, perm, 4) 154 155 #define fs_param_cb(name, ops, arg, perm) \ 156 __level_param_cb(name, ops, arg, perm, 5) 157 158 #define device_param_cb(name, ops, arg, perm) \ 159 __level_param_cb(name, ops, arg, perm, 6) 160 161 #define late_param_cb(name, ops, arg, perm) \ 162 __level_param_cb(name, ops, arg, perm, 7) 163 164 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 165 read-only sections (which is part of respective UNIX ABI on these 166 platforms). So 'const' makes no sense and even causes compile failures 167 with some compilers. */ 168 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 169 #define __moduleparam_const 170 #else 171 #define __moduleparam_const const 172 #endif 173 174 /* This is the fundamental function for registering boot/module 175 parameters. */ 176 #define __module_param_call(prefix, name, ops, arg, perm, level) \ 177 /* Default value instead of permissions? */ \ 178 static int __param_perm_check_##name __attribute__((unused)) = \ 179 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ 180 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \ 181 static const char __param_str_##name[] = prefix #name; \ 182 static struct kernel_param __moduleparam_const __param_##name \ 183 __used \ 184 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 185 = { __param_str_##name, ops, perm, level, { arg } } 186 187 /* Obsolete - use module_param_cb() */ 188 #define module_param_call(name, set, get, arg, perm) \ 189 static struct kernel_param_ops __param_ops_##name = \ 190 { (void *)set, (void *)get }; \ 191 __module_param_call(MODULE_PARAM_PREFIX, \ 192 name, &__param_ops_##name, arg, \ 193 (perm) + sizeof(__check_old_set_param(set))*0, -1) 194 195 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 196 static inline int 197 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 198 { 199 return 0; 200 } 201 202 /** 203 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 204 * @name: the name of the parameter 205 * 206 * There's no point blocking write on a paramter that isn't writable via sysfs! 207 */ 208 #define kparam_block_sysfs_write(name) \ 209 do { \ 210 BUG_ON(!(__param_##name.perm & 0222)); \ 211 __kernel_param_lock(); \ 212 } while (0) 213 214 /** 215 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 216 * @name: the name of the parameter 217 */ 218 #define kparam_unblock_sysfs_write(name) \ 219 do { \ 220 BUG_ON(!(__param_##name.perm & 0222)); \ 221 __kernel_param_unlock(); \ 222 } while (0) 223 224 /** 225 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 226 * @name: the name of the parameter 227 * 228 * This also blocks sysfs writes. 229 */ 230 #define kparam_block_sysfs_read(name) \ 231 do { \ 232 BUG_ON(!(__param_##name.perm & 0444)); \ 233 __kernel_param_lock(); \ 234 } while (0) 235 236 /** 237 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 238 * @name: the name of the parameter 239 */ 240 #define kparam_unblock_sysfs_read(name) \ 241 do { \ 242 BUG_ON(!(__param_##name.perm & 0444)); \ 243 __kernel_param_unlock(); \ 244 } while (0) 245 246 #ifdef CONFIG_SYSFS 247 extern void __kernel_param_lock(void); 248 extern void __kernel_param_unlock(void); 249 #else 250 static inline void __kernel_param_lock(void) 251 { 252 } 253 static inline void __kernel_param_unlock(void) 254 { 255 } 256 #endif 257 258 #ifndef MODULE 259 /** 260 * core_param - define a historical core kernel parameter. 261 * @name: the name of the cmdline and sysfs parameter (often the same as var) 262 * @var: the variable 263 * @type: the type of the parameter 264 * @perm: visibility in sysfs 265 * 266 * core_param is just like module_param(), but cannot be modular and 267 * doesn't add a prefix (such as "printk."). This is for compatibility 268 * with __setup(), and it makes sense as truly core parameters aren't 269 * tied to the particular file they're in. 270 */ 271 #define core_param(name, var, type, perm) \ 272 param_check_##type(name, &(var)); \ 273 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1) 274 #endif /* !MODULE */ 275 276 /** 277 * module_param_string - a char array parameter 278 * @name: the name of the parameter 279 * @string: the string variable 280 * @len: the maximum length of the string, incl. terminator 281 * @perm: visibility in sysfs. 282 * 283 * This actually copies the string when it's set (unlike type charp). 284 * @len is usually just sizeof(string). 285 */ 286 #define module_param_string(name, string, len, perm) \ 287 static const struct kparam_string __param_string_##name \ 288 = { len, string }; \ 289 __module_param_call(MODULE_PARAM_PREFIX, name, \ 290 ¶m_ops_string, \ 291 .str = &__param_string_##name, perm, -1); \ 292 __MODULE_PARM_TYPE(name, "string") 293 294 /** 295 * parameq - checks if two parameter names match 296 * @name1: parameter name 1 297 * @name2: parameter name 2 298 * 299 * Returns true if the two parameter names are equal. 300 * Dashes (-) are considered equal to underscores (_). 301 */ 302 extern bool parameq(const char *name1, const char *name2); 303 304 /** 305 * parameqn - checks if two parameter names match 306 * @name1: parameter name 1 307 * @name2: parameter name 2 308 * @n: the length to compare 309 * 310 * Similar to parameq(), except it compares @n characters. 311 */ 312 extern bool parameqn(const char *name1, const char *name2, size_t n); 313 314 /* Called on module insert or kernel boot */ 315 extern int parse_args(const char *name, 316 char *args, 317 const struct kernel_param *params, 318 unsigned num, 319 s16 level_min, 320 s16 level_max, 321 int (*unknown)(char *param, char *val, 322 const char *doing)); 323 324 /* Called by module remove. */ 325 #ifdef CONFIG_SYSFS 326 extern void destroy_params(const struct kernel_param *params, unsigned num); 327 #else 328 static inline void destroy_params(const struct kernel_param *params, 329 unsigned num) 330 { 331 } 332 #endif /* !CONFIG_SYSFS */ 333 334 /* All the helper functions */ 335 /* The macros to do compile-time type checking stolen from Jakub 336 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 337 #define __param_check(name, p, type) \ 338 static inline type *__check_##name(void) { return(p); } 339 340 extern struct kernel_param_ops param_ops_byte; 341 extern int param_set_byte(const char *val, const struct kernel_param *kp); 342 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 343 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 344 345 extern struct kernel_param_ops param_ops_short; 346 extern int param_set_short(const char *val, const struct kernel_param *kp); 347 extern int param_get_short(char *buffer, const struct kernel_param *kp); 348 #define param_check_short(name, p) __param_check(name, p, short) 349 350 extern struct kernel_param_ops param_ops_ushort; 351 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 352 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 353 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 354 355 extern struct kernel_param_ops param_ops_int; 356 extern int param_set_int(const char *val, const struct kernel_param *kp); 357 extern int param_get_int(char *buffer, const struct kernel_param *kp); 358 #define param_check_int(name, p) __param_check(name, p, int) 359 360 extern struct kernel_param_ops param_ops_uint; 361 extern int param_set_uint(const char *val, const struct kernel_param *kp); 362 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 363 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 364 365 extern struct kernel_param_ops param_ops_long; 366 extern int param_set_long(const char *val, const struct kernel_param *kp); 367 extern int param_get_long(char *buffer, const struct kernel_param *kp); 368 #define param_check_long(name, p) __param_check(name, p, long) 369 370 extern struct kernel_param_ops param_ops_ulong; 371 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 372 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 373 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 374 375 extern struct kernel_param_ops param_ops_charp; 376 extern int param_set_charp(const char *val, const struct kernel_param *kp); 377 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 378 #define param_check_charp(name, p) __param_check(name, p, char *) 379 380 /* We used to allow int as well as bool. We're taking that away! */ 381 extern struct kernel_param_ops param_ops_bool; 382 extern int param_set_bool(const char *val, const struct kernel_param *kp); 383 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 384 #define param_check_bool(name, p) __param_check(name, p, bool) 385 386 extern struct kernel_param_ops param_ops_invbool; 387 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 388 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 389 #define param_check_invbool(name, p) __param_check(name, p, bool) 390 391 /* An int, which can only be set like a bool (though it shows as an int). */ 392 extern struct kernel_param_ops param_ops_bint; 393 extern int param_set_bint(const char *val, const struct kernel_param *kp); 394 #define param_get_bint param_get_int 395 #define param_check_bint param_check_int 396 397 /** 398 * module_param_array - a parameter which is an array of some type 399 * @name: the name of the array variable 400 * @type: the type, as per module_param() 401 * @nump: optional pointer filled in with the number written 402 * @perm: visibility in sysfs 403 * 404 * Input and output are as comma-separated values. Commas inside values 405 * don't work properly (eg. an array of charp). 406 * 407 * ARRAY_SIZE(@name) is used to determine the number of elements in the 408 * array, so the definition must be visible. 409 */ 410 #define module_param_array(name, type, nump, perm) \ 411 module_param_array_named(name, name, type, nump, perm) 412 413 /** 414 * module_param_array_named - renamed parameter which is an array of some type 415 * @name: a valid C identifier which is the parameter name 416 * @array: the name of the array variable 417 * @type: the type, as per module_param() 418 * @nump: optional pointer filled in with the number written 419 * @perm: visibility in sysfs 420 * 421 * This exposes a different name than the actual variable name. See 422 * module_param_named() for why this might be necessary. 423 */ 424 #define module_param_array_named(name, array, type, nump, perm) \ 425 param_check_##type(name, &(array)[0]); \ 426 static const struct kparam_array __param_arr_##name \ 427 = { .max = ARRAY_SIZE(array), .num = nump, \ 428 .ops = ¶m_ops_##type, \ 429 .elemsize = sizeof(array[0]), .elem = array }; \ 430 __module_param_call(MODULE_PARAM_PREFIX, name, \ 431 ¶m_array_ops, \ 432 .arr = &__param_arr_##name, \ 433 perm, -1); \ 434 __MODULE_PARM_TYPE(name, "array of " #type) 435 436 extern struct kernel_param_ops param_array_ops; 437 438 extern struct kernel_param_ops param_ops_string; 439 extern int param_set_copystring(const char *val, const struct kernel_param *); 440 extern int param_get_string(char *buffer, const struct kernel_param *kp); 441 442 /* for exporting parameters in /sys/parameters */ 443 444 struct module; 445 446 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 447 extern int module_param_sysfs_setup(struct module *mod, 448 const struct kernel_param *kparam, 449 unsigned int num_params); 450 451 extern void module_param_sysfs_remove(struct module *mod); 452 #else 453 static inline int module_param_sysfs_setup(struct module *mod, 454 const struct kernel_param *kparam, 455 unsigned int num_params) 456 { 457 return 0; 458 } 459 460 static inline void module_param_sysfs_remove(struct module *mod) 461 { } 462 #endif 463 464 #endif /* _LINUX_MODULE_PARAMS_H */ 465