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_OPS_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 /* 60 * Flags available for kernel_param 61 * 62 * UNSAFE - the parameter is dangerous and setting it will taint the kernel 63 */ 64 enum { 65 KERNEL_PARAM_FL_UNSAFE = (1 << 0) 66 }; 67 68 struct kernel_param { 69 const char *name; 70 const struct kernel_param_ops *ops; 71 u16 perm; 72 s8 level; 73 u8 flags; 74 union { 75 void *arg; 76 const struct kparam_string *str; 77 const struct kparam_array *arr; 78 }; 79 }; 80 81 /* Special one for strings we want to copy into */ 82 struct kparam_string { 83 unsigned int maxlen; 84 char *string; 85 }; 86 87 /* Special one for arrays */ 88 struct kparam_array 89 { 90 unsigned int max; 91 unsigned int elemsize; 92 unsigned int *num; 93 const struct kernel_param_ops *ops; 94 void *elem; 95 }; 96 97 /** 98 * module_param - typesafe helper for a module/cmdline parameter 99 * @value: the variable to alter, and exposed parameter name. 100 * @type: the type of the parameter 101 * @perm: visibility in sysfs. 102 * 103 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 104 * ".") the kernel commandline parameter. Note that - is changed to _, so 105 * the user can use "foo-bar=1" even for variable "foo_bar". 106 * 107 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 108 * for world-readable, 0644 for root-writable, etc. Note that if it 109 * is writable, you may need to use kparam_block_sysfs_write() around 110 * accesses (esp. charp, which can be kfreed when it changes). 111 * 112 * The @type is simply pasted to refer to a param_ops_##type and a 113 * param_check_##type: for convenience many standard types are provided but 114 * you can create your own by defining those variables. 115 * 116 * Standard types are: 117 * byte, short, ushort, int, uint, long, ulong 118 * charp: a character pointer 119 * bool: a bool, values 0/1, y/n, Y/N. 120 * invbool: the above, only sense-reversed (N = true). 121 */ 122 #define module_param(name, type, perm) \ 123 module_param_named(name, name, type, perm) 124 125 /** 126 * module_param_unsafe - same as module_param but taints kernel 127 */ 128 #define module_param_unsafe(name, type, perm) \ 129 module_param_named_unsafe(name, name, type, perm) 130 131 /** 132 * module_param_named - typesafe helper for a renamed module/cmdline parameter 133 * @name: a valid C identifier which is the parameter name. 134 * @value: the actual lvalue to alter. 135 * @type: the type of the parameter 136 * @perm: visibility in sysfs. 137 * 138 * Usually it's a good idea to have variable names and user-exposed names the 139 * same, but that's harder if the variable must be non-static or is inside a 140 * structure. This allows exposure under a different name. 141 */ 142 #define module_param_named(name, value, type, perm) \ 143 param_check_##type(name, &(value)); \ 144 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 145 __MODULE_PARM_TYPE(name, #type) 146 147 /** 148 * module_param_named_unsafe - same as module_param_named but taints kernel 149 */ 150 #define module_param_named_unsafe(name, value, type, perm) \ 151 param_check_##type(name, &(value)); \ 152 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \ 153 __MODULE_PARM_TYPE(name, #type) 154 155 /** 156 * module_param_cb - general callback for a module/cmdline parameter 157 * @name: a valid C identifier which is the parameter name. 158 * @ops: the set & get operations for this parameter. 159 * @perm: visibility in sysfs. 160 * 161 * The ops can have NULL set or get functions. 162 */ 163 #define module_param_cb(name, ops, arg, perm) \ 164 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0) 165 166 #define module_param_cb_unsafe(name, ops, arg, perm) \ 167 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \ 168 KERNEL_PARAM_FL_UNSAFE) 169 170 /** 171 * <level>_param_cb - general callback for a module/cmdline parameter 172 * to be evaluated before certain initcall level 173 * @name: a valid C identifier which is the parameter name. 174 * @ops: the set & get operations for this parameter. 175 * @perm: visibility in sysfs. 176 * 177 * The ops can have NULL set or get functions. 178 */ 179 #define __level_param_cb(name, ops, arg, perm, level) \ 180 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0) 181 182 #define core_param_cb(name, ops, arg, perm) \ 183 __level_param_cb(name, ops, arg, perm, 1) 184 185 #define postcore_param_cb(name, ops, arg, perm) \ 186 __level_param_cb(name, ops, arg, perm, 2) 187 188 #define arch_param_cb(name, ops, arg, perm) \ 189 __level_param_cb(name, ops, arg, perm, 3) 190 191 #define subsys_param_cb(name, ops, arg, perm) \ 192 __level_param_cb(name, ops, arg, perm, 4) 193 194 #define fs_param_cb(name, ops, arg, perm) \ 195 __level_param_cb(name, ops, arg, perm, 5) 196 197 #define device_param_cb(name, ops, arg, perm) \ 198 __level_param_cb(name, ops, arg, perm, 6) 199 200 #define late_param_cb(name, ops, arg, perm) \ 201 __level_param_cb(name, ops, arg, perm, 7) 202 203 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 204 read-only sections (which is part of respective UNIX ABI on these 205 platforms). So 'const' makes no sense and even causes compile failures 206 with some compilers. */ 207 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 208 #define __moduleparam_const 209 #else 210 #define __moduleparam_const const 211 #endif 212 213 /* This is the fundamental function for registering boot/module 214 parameters. */ 215 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \ 216 /* Default value instead of permissions? */ \ 217 static const char __param_str_##name[] = prefix #name; \ 218 static struct kernel_param __moduleparam_const __param_##name \ 219 __used \ 220 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 221 = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \ 222 level, flags, { arg } } 223 224 /* Obsolete - use module_param_cb() */ 225 #define module_param_call(name, set, get, arg, perm) \ 226 static struct kernel_param_ops __param_ops_##name = \ 227 { .flags = 0, (void *)set, (void *)get }; \ 228 __module_param_call(MODULE_PARAM_PREFIX, \ 229 name, &__param_ops_##name, arg, \ 230 (perm) + sizeof(__check_old_set_param(set))*0, -1, 0) 231 232 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 233 static inline int 234 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 235 { 236 return 0; 237 } 238 239 /** 240 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 241 * @name: the name of the parameter 242 * 243 * There's no point blocking write on a paramter that isn't writable via sysfs! 244 */ 245 #define kparam_block_sysfs_write(name) \ 246 do { \ 247 BUG_ON(!(__param_##name.perm & 0222)); \ 248 __kernel_param_lock(); \ 249 } while (0) 250 251 /** 252 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 253 * @name: the name of the parameter 254 */ 255 #define kparam_unblock_sysfs_write(name) \ 256 do { \ 257 BUG_ON(!(__param_##name.perm & 0222)); \ 258 __kernel_param_unlock(); \ 259 } while (0) 260 261 /** 262 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 263 * @name: the name of the parameter 264 * 265 * This also blocks sysfs writes. 266 */ 267 #define kparam_block_sysfs_read(name) \ 268 do { \ 269 BUG_ON(!(__param_##name.perm & 0444)); \ 270 __kernel_param_lock(); \ 271 } while (0) 272 273 /** 274 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 275 * @name: the name of the parameter 276 */ 277 #define kparam_unblock_sysfs_read(name) \ 278 do { \ 279 BUG_ON(!(__param_##name.perm & 0444)); \ 280 __kernel_param_unlock(); \ 281 } while (0) 282 283 #ifdef CONFIG_SYSFS 284 extern void __kernel_param_lock(void); 285 extern void __kernel_param_unlock(void); 286 #else 287 static inline void __kernel_param_lock(void) 288 { 289 } 290 static inline void __kernel_param_unlock(void) 291 { 292 } 293 #endif 294 295 #ifndef MODULE 296 /** 297 * core_param - define a historical core kernel parameter. 298 * @name: the name of the cmdline and sysfs parameter (often the same as var) 299 * @var: the variable 300 * @type: the type of the parameter 301 * @perm: visibility in sysfs 302 * 303 * core_param is just like module_param(), but cannot be modular and 304 * doesn't add a prefix (such as "printk."). This is for compatibility 305 * with __setup(), and it makes sense as truly core parameters aren't 306 * tied to the particular file they're in. 307 */ 308 #define core_param(name, var, type, perm) \ 309 param_check_##type(name, &(var)); \ 310 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0) 311 #endif /* !MODULE */ 312 313 /** 314 * module_param_string - a char array parameter 315 * @name: the name of the parameter 316 * @string: the string variable 317 * @len: the maximum length of the string, incl. terminator 318 * @perm: visibility in sysfs. 319 * 320 * This actually copies the string when it's set (unlike type charp). 321 * @len is usually just sizeof(string). 322 */ 323 #define module_param_string(name, string, len, perm) \ 324 static const struct kparam_string __param_string_##name \ 325 = { len, string }; \ 326 __module_param_call(MODULE_PARAM_PREFIX, name, \ 327 ¶m_ops_string, \ 328 .str = &__param_string_##name, perm, -1, 0);\ 329 __MODULE_PARM_TYPE(name, "string") 330 331 /** 332 * parameq - checks if two parameter names match 333 * @name1: parameter name 1 334 * @name2: parameter name 2 335 * 336 * Returns true if the two parameter names are equal. 337 * Dashes (-) are considered equal to underscores (_). 338 */ 339 extern bool parameq(const char *name1, const char *name2); 340 341 /** 342 * parameqn - checks if two parameter names match 343 * @name1: parameter name 1 344 * @name2: parameter name 2 345 * @n: the length to compare 346 * 347 * Similar to parameq(), except it compares @n characters. 348 */ 349 extern bool parameqn(const char *name1, const char *name2, size_t n); 350 351 /* Called on module insert or kernel boot */ 352 extern char *parse_args(const char *name, 353 char *args, 354 const struct kernel_param *params, 355 unsigned num, 356 s16 level_min, 357 s16 level_max, 358 int (*unknown)(char *param, char *val, 359 const char *doing)); 360 361 /* Called by module remove. */ 362 #ifdef CONFIG_SYSFS 363 extern void destroy_params(const struct kernel_param *params, unsigned num); 364 #else 365 static inline void destroy_params(const struct kernel_param *params, 366 unsigned num) 367 { 368 } 369 #endif /* !CONFIG_SYSFS */ 370 371 /* All the helper functions */ 372 /* The macros to do compile-time type checking stolen from Jakub 373 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 374 #define __param_check(name, p, type) \ 375 static inline type __always_unused *__check_##name(void) { return(p); } 376 377 extern struct kernel_param_ops param_ops_byte; 378 extern int param_set_byte(const char *val, const struct kernel_param *kp); 379 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 380 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 381 382 extern struct kernel_param_ops param_ops_short; 383 extern int param_set_short(const char *val, const struct kernel_param *kp); 384 extern int param_get_short(char *buffer, const struct kernel_param *kp); 385 #define param_check_short(name, p) __param_check(name, p, short) 386 387 extern struct kernel_param_ops param_ops_ushort; 388 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 389 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 390 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 391 392 extern struct kernel_param_ops param_ops_int; 393 extern int param_set_int(const char *val, const struct kernel_param *kp); 394 extern int param_get_int(char *buffer, const struct kernel_param *kp); 395 #define param_check_int(name, p) __param_check(name, p, int) 396 397 extern struct kernel_param_ops param_ops_uint; 398 extern int param_set_uint(const char *val, const struct kernel_param *kp); 399 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 400 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 401 402 extern struct kernel_param_ops param_ops_long; 403 extern int param_set_long(const char *val, const struct kernel_param *kp); 404 extern int param_get_long(char *buffer, const struct kernel_param *kp); 405 #define param_check_long(name, p) __param_check(name, p, long) 406 407 extern struct kernel_param_ops param_ops_ulong; 408 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 409 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 410 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 411 412 extern struct kernel_param_ops param_ops_ullong; 413 extern int param_set_ullong(const char *val, const struct kernel_param *kp); 414 extern int param_get_ullong(char *buffer, const struct kernel_param *kp); 415 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long) 416 417 extern struct kernel_param_ops param_ops_charp; 418 extern int param_set_charp(const char *val, const struct kernel_param *kp); 419 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 420 #define param_check_charp(name, p) __param_check(name, p, char *) 421 422 /* We used to allow int as well as bool. We're taking that away! */ 423 extern struct kernel_param_ops param_ops_bool; 424 extern int param_set_bool(const char *val, const struct kernel_param *kp); 425 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 426 #define param_check_bool(name, p) __param_check(name, p, bool) 427 428 extern struct kernel_param_ops param_ops_invbool; 429 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 430 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 431 #define param_check_invbool(name, p) __param_check(name, p, bool) 432 433 /* An int, which can only be set like a bool (though it shows as an int). */ 434 extern struct kernel_param_ops param_ops_bint; 435 extern int param_set_bint(const char *val, const struct kernel_param *kp); 436 #define param_get_bint param_get_int 437 #define param_check_bint param_check_int 438 439 /** 440 * module_param_array - a parameter which is an array of some type 441 * @name: the name of the array variable 442 * @type: the type, as per module_param() 443 * @nump: optional pointer filled in with the number written 444 * @perm: visibility in sysfs 445 * 446 * Input and output are as comma-separated values. Commas inside values 447 * don't work properly (eg. an array of charp). 448 * 449 * ARRAY_SIZE(@name) is used to determine the number of elements in the 450 * array, so the definition must be visible. 451 */ 452 #define module_param_array(name, type, nump, perm) \ 453 module_param_array_named(name, name, type, nump, perm) 454 455 /** 456 * module_param_array_named - renamed parameter which is an array of some type 457 * @name: a valid C identifier which is the parameter name 458 * @array: the name of the array variable 459 * @type: the type, as per module_param() 460 * @nump: optional pointer filled in with the number written 461 * @perm: visibility in sysfs 462 * 463 * This exposes a different name than the actual variable name. See 464 * module_param_named() for why this might be necessary. 465 */ 466 #define module_param_array_named(name, array, type, nump, perm) \ 467 param_check_##type(name, &(array)[0]); \ 468 static const struct kparam_array __param_arr_##name \ 469 = { .max = ARRAY_SIZE(array), .num = nump, \ 470 .ops = ¶m_ops_##type, \ 471 .elemsize = sizeof(array[0]), .elem = array }; \ 472 __module_param_call(MODULE_PARAM_PREFIX, name, \ 473 ¶m_array_ops, \ 474 .arr = &__param_arr_##name, \ 475 perm, -1, 0); \ 476 __MODULE_PARM_TYPE(name, "array of " #type) 477 478 extern struct kernel_param_ops param_array_ops; 479 480 extern struct kernel_param_ops param_ops_string; 481 extern int param_set_copystring(const char *val, const struct kernel_param *); 482 extern int param_get_string(char *buffer, const struct kernel_param *kp); 483 484 /* for exporting parameters in /sys/module/.../parameters */ 485 486 struct module; 487 488 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 489 extern int module_param_sysfs_setup(struct module *mod, 490 const struct kernel_param *kparam, 491 unsigned int num_params); 492 493 extern void module_param_sysfs_remove(struct module *mod); 494 #else 495 static inline int module_param_sysfs_setup(struct module *mod, 496 const struct kernel_param *kparam, 497 unsigned int num_params) 498 { 499 return 0; 500 } 501 502 static inline void module_param_sysfs_remove(struct module *mod) 503 { } 504 #endif 505 506 #endif /* _LINUX_MODULE_PARAMS_H */ 507