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 const char __param_str_##name[] = prefix #name; \ 190 static struct kernel_param __moduleparam_const __param_##name \ 191 __used \ 192 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 193 = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \ 194 level, { arg } } 195 196 /* Obsolete - use module_param_cb() */ 197 #define module_param_call(name, set, get, arg, perm) \ 198 static struct kernel_param_ops __param_ops_##name = \ 199 { 0, (void *)set, (void *)get }; \ 200 __module_param_call(MODULE_PARAM_PREFIX, \ 201 name, &__param_ops_##name, arg, \ 202 (perm) + sizeof(__check_old_set_param(set))*0, -1) 203 204 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 205 static inline int 206 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 207 { 208 return 0; 209 } 210 211 /** 212 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 213 * @name: the name of the parameter 214 * 215 * There's no point blocking write on a paramter that isn't writable via sysfs! 216 */ 217 #define kparam_block_sysfs_write(name) \ 218 do { \ 219 BUG_ON(!(__param_##name.perm & 0222)); \ 220 __kernel_param_lock(); \ 221 } while (0) 222 223 /** 224 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 225 * @name: the name of the parameter 226 */ 227 #define kparam_unblock_sysfs_write(name) \ 228 do { \ 229 BUG_ON(!(__param_##name.perm & 0222)); \ 230 __kernel_param_unlock(); \ 231 } while (0) 232 233 /** 234 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 235 * @name: the name of the parameter 236 * 237 * This also blocks sysfs writes. 238 */ 239 #define kparam_block_sysfs_read(name) \ 240 do { \ 241 BUG_ON(!(__param_##name.perm & 0444)); \ 242 __kernel_param_lock(); \ 243 } while (0) 244 245 /** 246 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 247 * @name: the name of the parameter 248 */ 249 #define kparam_unblock_sysfs_read(name) \ 250 do { \ 251 BUG_ON(!(__param_##name.perm & 0444)); \ 252 __kernel_param_unlock(); \ 253 } while (0) 254 255 #ifdef CONFIG_SYSFS 256 extern void __kernel_param_lock(void); 257 extern void __kernel_param_unlock(void); 258 #else 259 static inline void __kernel_param_lock(void) 260 { 261 } 262 static inline void __kernel_param_unlock(void) 263 { 264 } 265 #endif 266 267 #ifndef MODULE 268 /** 269 * core_param - define a historical core kernel parameter. 270 * @name: the name of the cmdline and sysfs parameter (often the same as var) 271 * @var: the variable 272 * @type: the type of the parameter 273 * @perm: visibility in sysfs 274 * 275 * core_param is just like module_param(), but cannot be modular and 276 * doesn't add a prefix (such as "printk."). This is for compatibility 277 * with __setup(), and it makes sense as truly core parameters aren't 278 * tied to the particular file they're in. 279 */ 280 #define core_param(name, var, type, perm) \ 281 param_check_##type(name, &(var)); \ 282 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1) 283 #endif /* !MODULE */ 284 285 /** 286 * module_param_string - a char array parameter 287 * @name: the name of the parameter 288 * @string: the string variable 289 * @len: the maximum length of the string, incl. terminator 290 * @perm: visibility in sysfs. 291 * 292 * This actually copies the string when it's set (unlike type charp). 293 * @len is usually just sizeof(string). 294 */ 295 #define module_param_string(name, string, len, perm) \ 296 static const struct kparam_string __param_string_##name \ 297 = { len, string }; \ 298 __module_param_call(MODULE_PARAM_PREFIX, name, \ 299 ¶m_ops_string, \ 300 .str = &__param_string_##name, perm, -1); \ 301 __MODULE_PARM_TYPE(name, "string") 302 303 /** 304 * parameq - checks if two parameter names match 305 * @name1: parameter name 1 306 * @name2: parameter name 2 307 * 308 * Returns true if the two parameter names are equal. 309 * Dashes (-) are considered equal to underscores (_). 310 */ 311 extern bool parameq(const char *name1, const char *name2); 312 313 /** 314 * parameqn - checks if two parameter names match 315 * @name1: parameter name 1 316 * @name2: parameter name 2 317 * @n: the length to compare 318 * 319 * Similar to parameq(), except it compares @n characters. 320 */ 321 extern bool parameqn(const char *name1, const char *name2, size_t n); 322 323 /* Called on module insert or kernel boot */ 324 extern char *parse_args(const char *name, 325 char *args, 326 const struct kernel_param *params, 327 unsigned num, 328 s16 level_min, 329 s16 level_max, 330 int (*unknown)(char *param, char *val, 331 const char *doing)); 332 333 /* Called by module remove. */ 334 #ifdef CONFIG_SYSFS 335 extern void destroy_params(const struct kernel_param *params, unsigned num); 336 #else 337 static inline void destroy_params(const struct kernel_param *params, 338 unsigned num) 339 { 340 } 341 #endif /* !CONFIG_SYSFS */ 342 343 /* All the helper functions */ 344 /* The macros to do compile-time type checking stolen from Jakub 345 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 346 #define __param_check(name, p, type) \ 347 static inline type __always_unused *__check_##name(void) { return(p); } 348 349 extern struct kernel_param_ops param_ops_byte; 350 extern int param_set_byte(const char *val, const struct kernel_param *kp); 351 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 352 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 353 354 extern struct kernel_param_ops param_ops_short; 355 extern int param_set_short(const char *val, const struct kernel_param *kp); 356 extern int param_get_short(char *buffer, const struct kernel_param *kp); 357 #define param_check_short(name, p) __param_check(name, p, short) 358 359 extern struct kernel_param_ops param_ops_ushort; 360 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 361 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 362 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 363 364 extern struct kernel_param_ops param_ops_int; 365 extern int param_set_int(const char *val, const struct kernel_param *kp); 366 extern int param_get_int(char *buffer, const struct kernel_param *kp); 367 #define param_check_int(name, p) __param_check(name, p, int) 368 369 extern struct kernel_param_ops param_ops_uint; 370 extern int param_set_uint(const char *val, const struct kernel_param *kp); 371 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 372 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 373 374 extern struct kernel_param_ops param_ops_long; 375 extern int param_set_long(const char *val, const struct kernel_param *kp); 376 extern int param_get_long(char *buffer, const struct kernel_param *kp); 377 #define param_check_long(name, p) __param_check(name, p, long) 378 379 extern struct kernel_param_ops param_ops_ulong; 380 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 381 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 382 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 383 384 extern struct kernel_param_ops param_ops_charp; 385 extern int param_set_charp(const char *val, const struct kernel_param *kp); 386 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 387 #define param_check_charp(name, p) __param_check(name, p, char *) 388 389 /* We used to allow int as well as bool. We're taking that away! */ 390 extern struct kernel_param_ops param_ops_bool; 391 extern int param_set_bool(const char *val, const struct kernel_param *kp); 392 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 393 #define param_check_bool(name, p) __param_check(name, p, bool) 394 395 extern struct kernel_param_ops param_ops_invbool; 396 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 397 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 398 #define param_check_invbool(name, p) __param_check(name, p, bool) 399 400 /* An int, which can only be set like a bool (though it shows as an int). */ 401 extern struct kernel_param_ops param_ops_bint; 402 extern int param_set_bint(const char *val, const struct kernel_param *kp); 403 #define param_get_bint param_get_int 404 #define param_check_bint param_check_int 405 406 /** 407 * module_param_array - a parameter which is an array of some type 408 * @name: the name of the array variable 409 * @type: the type, as per module_param() 410 * @nump: optional pointer filled in with the number written 411 * @perm: visibility in sysfs 412 * 413 * Input and output are as comma-separated values. Commas inside values 414 * don't work properly (eg. an array of charp). 415 * 416 * ARRAY_SIZE(@name) is used to determine the number of elements in the 417 * array, so the definition must be visible. 418 */ 419 #define module_param_array(name, type, nump, perm) \ 420 module_param_array_named(name, name, type, nump, perm) 421 422 /** 423 * module_param_array_named - renamed parameter which is an array of some type 424 * @name: a valid C identifier which is the parameter name 425 * @array: the name of the array variable 426 * @type: the type, as per module_param() 427 * @nump: optional pointer filled in with the number written 428 * @perm: visibility in sysfs 429 * 430 * This exposes a different name than the actual variable name. See 431 * module_param_named() for why this might be necessary. 432 */ 433 #define module_param_array_named(name, array, type, nump, perm) \ 434 param_check_##type(name, &(array)[0]); \ 435 static const struct kparam_array __param_arr_##name \ 436 = { .max = ARRAY_SIZE(array), .num = nump, \ 437 .ops = ¶m_ops_##type, \ 438 .elemsize = sizeof(array[0]), .elem = array }; \ 439 __module_param_call(MODULE_PARAM_PREFIX, name, \ 440 ¶m_array_ops, \ 441 .arr = &__param_arr_##name, \ 442 perm, -1); \ 443 __MODULE_PARM_TYPE(name, "array of " #type) 444 445 extern struct kernel_param_ops param_array_ops; 446 447 extern struct kernel_param_ops param_ops_string; 448 extern int param_set_copystring(const char *val, const struct kernel_param *); 449 extern int param_get_string(char *buffer, const struct kernel_param *kp); 450 451 /* for exporting parameters in /sys/module/.../parameters */ 452 453 struct module; 454 455 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 456 extern int module_param_sysfs_setup(struct module *mod, 457 const struct kernel_param *kparam, 458 unsigned int num_params); 459 460 extern void module_param_sysfs_remove(struct module *mod); 461 #else 462 static inline int module_param_sysfs_setup(struct module *mod, 463 const struct kernel_param *kparam, 464 unsigned int num_params) 465 { 466 return 0; 467 } 468 469 static inline void module_param_sysfs_remove(struct module *mod) 470 { } 471 #endif 472 473 #endif /* _LINUX_MODULE_PARAMS_H */ 474