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 /* 40 * Flags available for kernel_param_ops 41 * 42 * NOARG - the parameter allows for no argument (foo instead of foo=1) 43 */ 44 enum { 45 KERNEL_PARAM_FL_NOARG = (1 << 0) 46 }; 47 48 struct kernel_param_ops { 49 /* How the ops should behave */ 50 unsigned int flags; 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); 57 }; 58 59 struct kernel_param { 60 const char *name; 61 const struct kernel_param_ops *ops; 62 u16 perm; 63 s16 level; 64 union { 65 void *arg; 66 const struct kparam_string *str; 67 const struct kparam_array *arr; 68 }; 69 }; 70 71 /* Special one for strings we want to copy into */ 72 struct kparam_string { 73 unsigned int maxlen; 74 char *string; 75 }; 76 77 /* Special one for arrays */ 78 struct kparam_array 79 { 80 unsigned int max; 81 unsigned int elemsize; 82 unsigned int *num; 83 const struct kernel_param_ops *ops; 84 void *elem; 85 }; 86 87 /** 88 * module_param - typesafe helper for a module/cmdline parameter 89 * @value: the variable to alter, and exposed parameter name. 90 * @type: the type of the parameter 91 * @perm: visibility in sysfs. 92 * 93 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 94 * ".") the kernel commandline parameter. Note that - is changed to _, so 95 * the user can use "foo-bar=1" even for variable "foo_bar". 96 * 97 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 98 * for world-readable, 0644 for root-writable, etc. Note that if it 99 * is writable, you may need to use kparam_block_sysfs_write() around 100 * accesses (esp. charp, which can be kfreed when it changes). 101 * 102 * The @type is simply pasted to refer to a param_ops_##type and a 103 * param_check_##type: for convenience many standard types are provided but 104 * you can create your own by defining those variables. 105 * 106 * Standard types are: 107 * byte, short, ushort, int, uint, long, ulong 108 * charp: a character pointer 109 * bool: a bool, values 0/1, y/n, Y/N. 110 * invbool: the above, only sense-reversed (N = true). 111 */ 112 #define module_param(name, type, perm) \ 113 module_param_named(name, name, type, perm) 114 115 /** 116 * module_param_named - typesafe helper for a renamed module/cmdline parameter 117 * @name: a valid C identifier which is the parameter name. 118 * @value: the actual lvalue to alter. 119 * @type: the type of the parameter 120 * @perm: visibility in sysfs. 121 * 122 * Usually it's a good idea to have variable names and user-exposed names the 123 * same, but that's harder if the variable must be non-static or is inside a 124 * structure. This allows exposure under a different name. 125 */ 126 #define module_param_named(name, value, type, perm) \ 127 param_check_##type(name, &(value)); \ 128 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 129 __MODULE_PARM_TYPE(name, #type) 130 131 /** 132 * module_param_cb - general callback for a module/cmdline parameter 133 * @name: a valid C identifier which is the parameter name. 134 * @ops: the set & get operations for this parameter. 135 * @perm: visibility in sysfs. 136 * 137 * The ops can have NULL set or get functions. 138 */ 139 #define module_param_cb(name, ops, arg, perm) \ 140 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1) 141 142 /** 143 * <level>_param_cb - general callback for a module/cmdline parameter 144 * to be evaluated before certain initcall level 145 * @name: a valid C identifier which is the parameter name. 146 * @ops: the set & get operations for this parameter. 147 * @perm: visibility in sysfs. 148 * 149 * The ops can have NULL set or get functions. 150 */ 151 #define __level_param_cb(name, ops, arg, perm, level) \ 152 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level) 153 154 #define core_param_cb(name, ops, arg, perm) \ 155 __level_param_cb(name, ops, arg, perm, 1) 156 157 #define postcore_param_cb(name, ops, arg, perm) \ 158 __level_param_cb(name, ops, arg, perm, 2) 159 160 #define arch_param_cb(name, ops, arg, perm) \ 161 __level_param_cb(name, ops, arg, perm, 3) 162 163 #define subsys_param_cb(name, ops, arg, perm) \ 164 __level_param_cb(name, ops, arg, perm, 4) 165 166 #define fs_param_cb(name, ops, arg, perm) \ 167 __level_param_cb(name, ops, arg, perm, 5) 168 169 #define device_param_cb(name, ops, arg, perm) \ 170 __level_param_cb(name, ops, arg, perm, 6) 171 172 #define late_param_cb(name, ops, arg, perm) \ 173 __level_param_cb(name, ops, arg, perm, 7) 174 175 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 176 read-only sections (which is part of respective UNIX ABI on these 177 platforms). So 'const' makes no sense and even causes compile failures 178 with some compilers. */ 179 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 180 #define __moduleparam_const 181 #else 182 #define __moduleparam_const const 183 #endif 184 185 /* This is the fundamental function for registering boot/module 186 parameters. */ 187 #define __module_param_call(prefix, name, ops, arg, perm, level) \ 188 /* Default value instead of permissions? */ \ 189 static int __param_perm_check_##name __attribute__((unused)) = \ 190 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ 191 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \ 192 static const char __param_str_##name[] = prefix #name; \ 193 static struct kernel_param __moduleparam_const __param_##name \ 194 __used \ 195 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 196 = { __param_str_##name, ops, perm, level, { arg } } 197 198 /* Obsolete - use module_param_cb() */ 199 #define module_param_call(name, set, get, arg, perm) \ 200 static struct kernel_param_ops __param_ops_##name = \ 201 { 0, (void *)set, (void *)get }; \ 202 __module_param_call(MODULE_PARAM_PREFIX, \ 203 name, &__param_ops_##name, arg, \ 204 (perm) + sizeof(__check_old_set_param(set))*0, -1) 205 206 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 207 static inline int 208 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 209 { 210 return 0; 211 } 212 213 /** 214 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 215 * @name: the name of the parameter 216 * 217 * There's no point blocking write on a paramter that isn't writable via sysfs! 218 */ 219 #define kparam_block_sysfs_write(name) \ 220 do { \ 221 BUG_ON(!(__param_##name.perm & 0222)); \ 222 __kernel_param_lock(); \ 223 } while (0) 224 225 /** 226 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 227 * @name: the name of the parameter 228 */ 229 #define kparam_unblock_sysfs_write(name) \ 230 do { \ 231 BUG_ON(!(__param_##name.perm & 0222)); \ 232 __kernel_param_unlock(); \ 233 } while (0) 234 235 /** 236 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 237 * @name: the name of the parameter 238 * 239 * This also blocks sysfs writes. 240 */ 241 #define kparam_block_sysfs_read(name) \ 242 do { \ 243 BUG_ON(!(__param_##name.perm & 0444)); \ 244 __kernel_param_lock(); \ 245 } while (0) 246 247 /** 248 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 249 * @name: the name of the parameter 250 */ 251 #define kparam_unblock_sysfs_read(name) \ 252 do { \ 253 BUG_ON(!(__param_##name.perm & 0444)); \ 254 __kernel_param_unlock(); \ 255 } while (0) 256 257 #ifdef CONFIG_SYSFS 258 extern void __kernel_param_lock(void); 259 extern void __kernel_param_unlock(void); 260 #else 261 static inline void __kernel_param_lock(void) 262 { 263 } 264 static inline void __kernel_param_unlock(void) 265 { 266 } 267 #endif 268 269 #ifndef MODULE 270 /** 271 * core_param - define a historical core kernel parameter. 272 * @name: the name of the cmdline and sysfs parameter (often the same as var) 273 * @var: the variable 274 * @type: the type of the parameter 275 * @perm: visibility in sysfs 276 * 277 * core_param is just like module_param(), but cannot be modular and 278 * doesn't add a prefix (such as "printk."). This is for compatibility 279 * with __setup(), and it makes sense as truly core parameters aren't 280 * tied to the particular file they're in. 281 */ 282 #define core_param(name, var, type, perm) \ 283 param_check_##type(name, &(var)); \ 284 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1) 285 #endif /* !MODULE */ 286 287 /** 288 * module_param_string - a char array parameter 289 * @name: the name of the parameter 290 * @string: the string variable 291 * @len: the maximum length of the string, incl. terminator 292 * @perm: visibility in sysfs. 293 * 294 * This actually copies the string when it's set (unlike type charp). 295 * @len is usually just sizeof(string). 296 */ 297 #define module_param_string(name, string, len, perm) \ 298 static const struct kparam_string __param_string_##name \ 299 = { len, string }; \ 300 __module_param_call(MODULE_PARAM_PREFIX, name, \ 301 ¶m_ops_string, \ 302 .str = &__param_string_##name, perm, -1); \ 303 __MODULE_PARM_TYPE(name, "string") 304 305 /** 306 * parameq - checks if two parameter names match 307 * @name1: parameter name 1 308 * @name2: parameter name 2 309 * 310 * Returns true if the two parameter names are equal. 311 * Dashes (-) are considered equal to underscores (_). 312 */ 313 extern bool parameq(const char *name1, const char *name2); 314 315 /** 316 * parameqn - checks if two parameter names match 317 * @name1: parameter name 1 318 * @name2: parameter name 2 319 * @n: the length to compare 320 * 321 * Similar to parameq(), except it compares @n characters. 322 */ 323 extern bool parameqn(const char *name1, const char *name2, size_t n); 324 325 /* Called on module insert or kernel boot */ 326 extern int parse_args(const char *name, 327 char *args, 328 const struct kernel_param *params, 329 unsigned num, 330 s16 level_min, 331 s16 level_max, 332 int (*unknown)(char *param, char *val, 333 const char *doing)); 334 335 /* Called by module remove. */ 336 #ifdef CONFIG_SYSFS 337 extern void destroy_params(const struct kernel_param *params, unsigned num); 338 #else 339 static inline void destroy_params(const struct kernel_param *params, 340 unsigned num) 341 { 342 } 343 #endif /* !CONFIG_SYSFS */ 344 345 /* All the helper functions */ 346 /* The macros to do compile-time type checking stolen from Jakub 347 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 348 #define __param_check(name, p, type) \ 349 static inline type *__check_##name(void) { return(p); } 350 351 extern struct kernel_param_ops param_ops_byte; 352 extern int param_set_byte(const char *val, const struct kernel_param *kp); 353 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 354 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 355 356 extern struct kernel_param_ops param_ops_short; 357 extern int param_set_short(const char *val, const struct kernel_param *kp); 358 extern int param_get_short(char *buffer, const struct kernel_param *kp); 359 #define param_check_short(name, p) __param_check(name, p, short) 360 361 extern struct kernel_param_ops param_ops_ushort; 362 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 363 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 364 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 365 366 extern struct kernel_param_ops param_ops_int; 367 extern int param_set_int(const char *val, const struct kernel_param *kp); 368 extern int param_get_int(char *buffer, const struct kernel_param *kp); 369 #define param_check_int(name, p) __param_check(name, p, int) 370 371 extern struct kernel_param_ops param_ops_uint; 372 extern int param_set_uint(const char *val, const struct kernel_param *kp); 373 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 374 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 375 376 extern struct kernel_param_ops param_ops_long; 377 extern int param_set_long(const char *val, const struct kernel_param *kp); 378 extern int param_get_long(char *buffer, const struct kernel_param *kp); 379 #define param_check_long(name, p) __param_check(name, p, long) 380 381 extern struct kernel_param_ops param_ops_ulong; 382 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 383 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 384 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 385 386 extern struct kernel_param_ops param_ops_charp; 387 extern int param_set_charp(const char *val, const struct kernel_param *kp); 388 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 389 #define param_check_charp(name, p) __param_check(name, p, char *) 390 391 /* We used to allow int as well as bool. We're taking that away! */ 392 extern struct kernel_param_ops param_ops_bool; 393 extern int param_set_bool(const char *val, const struct kernel_param *kp); 394 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 395 #define param_check_bool(name, p) __param_check(name, p, bool) 396 397 extern struct kernel_param_ops param_ops_invbool; 398 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 399 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 400 #define param_check_invbool(name, p) __param_check(name, p, bool) 401 402 /* An int, which can only be set like a bool (though it shows as an int). */ 403 extern struct kernel_param_ops param_ops_bint; 404 extern int param_set_bint(const char *val, const struct kernel_param *kp); 405 #define param_get_bint param_get_int 406 #define param_check_bint param_check_int 407 408 /** 409 * module_param_array - a parameter which is an array of some type 410 * @name: the name of the array variable 411 * @type: the type, as per module_param() 412 * @nump: optional pointer filled in with the number written 413 * @perm: visibility in sysfs 414 * 415 * Input and output are as comma-separated values. Commas inside values 416 * don't work properly (eg. an array of charp). 417 * 418 * ARRAY_SIZE(@name) is used to determine the number of elements in the 419 * array, so the definition must be visible. 420 */ 421 #define module_param_array(name, type, nump, perm) \ 422 module_param_array_named(name, name, type, nump, perm) 423 424 /** 425 * module_param_array_named - renamed parameter which is an array of some type 426 * @name: a valid C identifier which is the parameter name 427 * @array: the name of the array variable 428 * @type: the type, as per module_param() 429 * @nump: optional pointer filled in with the number written 430 * @perm: visibility in sysfs 431 * 432 * This exposes a different name than the actual variable name. See 433 * module_param_named() for why this might be necessary. 434 */ 435 #define module_param_array_named(name, array, type, nump, perm) \ 436 param_check_##type(name, &(array)[0]); \ 437 static const struct kparam_array __param_arr_##name \ 438 = { .max = ARRAY_SIZE(array), .num = nump, \ 439 .ops = ¶m_ops_##type, \ 440 .elemsize = sizeof(array[0]), .elem = array }; \ 441 __module_param_call(MODULE_PARAM_PREFIX, name, \ 442 ¶m_array_ops, \ 443 .arr = &__param_arr_##name, \ 444 perm, -1); \ 445 __MODULE_PARM_TYPE(name, "array of " #type) 446 447 extern struct kernel_param_ops param_array_ops; 448 449 extern struct kernel_param_ops param_ops_string; 450 extern int param_set_copystring(const char *val, const struct kernel_param *); 451 extern int param_get_string(char *buffer, const struct kernel_param *kp); 452 453 /* for exporting parameters in /sys/module/.../parameters */ 454 455 struct module; 456 457 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 458 extern int module_param_sysfs_setup(struct module *mod, 459 const struct kernel_param *kparam, 460 unsigned int num_params); 461 462 extern void module_param_sysfs_remove(struct module *mod); 463 #else 464 static inline int module_param_sysfs_setup(struct module *mod, 465 const struct kernel_param *kparam, 466 unsigned int num_params) 467 { 468 return 0; 469 } 470 471 static inline void module_param_sysfs_remove(struct module *mod) 472 { } 473 #endif 474 475 #endif /* _LINUX_MODULE_PARAMS_H */ 476