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 extern const struct kernel_param __start___param[], __stop___param[]; 82 83 /* Special one for strings we want to copy into */ 84 struct kparam_string { 85 unsigned int maxlen; 86 char *string; 87 }; 88 89 /* Special one for arrays */ 90 struct kparam_array 91 { 92 unsigned int max; 93 unsigned int elemsize; 94 unsigned int *num; 95 const struct kernel_param_ops *ops; 96 void *elem; 97 }; 98 99 /** 100 * module_param - typesafe helper for a module/cmdline parameter 101 * @value: the variable to alter, and exposed parameter name. 102 * @type: the type of the parameter 103 * @perm: visibility in sysfs. 104 * 105 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 106 * ".") the kernel commandline parameter. Note that - is changed to _, so 107 * the user can use "foo-bar=1" even for variable "foo_bar". 108 * 109 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 110 * for world-readable, 0644 for root-writable, etc. Note that if it 111 * is writable, you may need to use kparam_block_sysfs_write() around 112 * accesses (esp. charp, which can be kfreed when it changes). 113 * 114 * The @type is simply pasted to refer to a param_ops_##type and a 115 * param_check_##type: for convenience many standard types are provided but 116 * you can create your own by defining those variables. 117 * 118 * Standard types are: 119 * byte, short, ushort, int, uint, long, ulong 120 * charp: a character pointer 121 * bool: a bool, values 0/1, y/n, Y/N. 122 * invbool: the above, only sense-reversed (N = true). 123 */ 124 #define module_param(name, type, perm) \ 125 module_param_named(name, name, type, perm) 126 127 /** 128 * module_param_unsafe - same as module_param but taints kernel 129 */ 130 #define module_param_unsafe(name, type, perm) \ 131 module_param_named_unsafe(name, name, type, perm) 132 133 /** 134 * module_param_named - typesafe helper for a renamed module/cmdline parameter 135 * @name: a valid C identifier which is the parameter name. 136 * @value: the actual lvalue to alter. 137 * @type: the type of the parameter 138 * @perm: visibility in sysfs. 139 * 140 * Usually it's a good idea to have variable names and user-exposed names the 141 * same, but that's harder if the variable must be non-static or is inside a 142 * structure. This allows exposure under a different name. 143 */ 144 #define module_param_named(name, value, type, perm) \ 145 param_check_##type(name, &(value)); \ 146 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 147 __MODULE_PARM_TYPE(name, #type) 148 149 /** 150 * module_param_named_unsafe - same as module_param_named but taints kernel 151 */ 152 #define module_param_named_unsafe(name, value, type, perm) \ 153 param_check_##type(name, &(value)); \ 154 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \ 155 __MODULE_PARM_TYPE(name, #type) 156 157 /** 158 * module_param_cb - general callback for a module/cmdline parameter 159 * @name: a valid C identifier which is the parameter name. 160 * @ops: the set & get operations for this parameter. 161 * @perm: visibility in sysfs. 162 * 163 * The ops can have NULL set or get functions. 164 */ 165 #define module_param_cb(name, ops, arg, perm) \ 166 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0) 167 168 #define module_param_cb_unsafe(name, ops, arg, perm) \ 169 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \ 170 KERNEL_PARAM_FL_UNSAFE) 171 172 /** 173 * <level>_param_cb - general callback for a module/cmdline parameter 174 * to be evaluated before certain initcall level 175 * @name: a valid C identifier which is the parameter name. 176 * @ops: the set & get operations for this parameter. 177 * @perm: visibility in sysfs. 178 * 179 * The ops can have NULL set or get functions. 180 */ 181 #define __level_param_cb(name, ops, arg, perm, level) \ 182 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0) 183 184 #define core_param_cb(name, ops, arg, perm) \ 185 __level_param_cb(name, ops, arg, perm, 1) 186 187 #define postcore_param_cb(name, ops, arg, perm) \ 188 __level_param_cb(name, ops, arg, perm, 2) 189 190 #define arch_param_cb(name, ops, arg, perm) \ 191 __level_param_cb(name, ops, arg, perm, 3) 192 193 #define subsys_param_cb(name, ops, arg, perm) \ 194 __level_param_cb(name, ops, arg, perm, 4) 195 196 #define fs_param_cb(name, ops, arg, perm) \ 197 __level_param_cb(name, ops, arg, perm, 5) 198 199 #define device_param_cb(name, ops, arg, perm) \ 200 __level_param_cb(name, ops, arg, perm, 6) 201 202 #define late_param_cb(name, ops, arg, perm) \ 203 __level_param_cb(name, ops, arg, perm, 7) 204 205 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 206 read-only sections (which is part of respective UNIX ABI on these 207 platforms). So 'const' makes no sense and even causes compile failures 208 with some compilers. */ 209 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 210 #define __moduleparam_const 211 #else 212 #define __moduleparam_const const 213 #endif 214 215 /* This is the fundamental function for registering boot/module 216 parameters. */ 217 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \ 218 /* Default value instead of permissions? */ \ 219 static const char __param_str_##name[] = prefix #name; \ 220 static struct kernel_param __moduleparam_const __param_##name \ 221 __used \ 222 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 223 = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \ 224 level, flags, { arg } } 225 226 /* Obsolete - use module_param_cb() */ 227 #define module_param_call(name, set, get, arg, perm) \ 228 static struct kernel_param_ops __param_ops_##name = \ 229 { .flags = 0, (void *)set, (void *)get }; \ 230 __module_param_call(MODULE_PARAM_PREFIX, \ 231 name, &__param_ops_##name, arg, \ 232 (perm) + sizeof(__check_old_set_param(set))*0, -1, 0) 233 234 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 235 static inline int 236 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 237 { 238 return 0; 239 } 240 241 /** 242 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 243 * @name: the name of the parameter 244 * 245 * There's no point blocking write on a paramter that isn't writable via sysfs! 246 */ 247 #define kparam_block_sysfs_write(name) \ 248 do { \ 249 BUG_ON(!(__param_##name.perm & 0222)); \ 250 __kernel_param_lock(); \ 251 } while (0) 252 253 /** 254 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 255 * @name: the name of the parameter 256 */ 257 #define kparam_unblock_sysfs_write(name) \ 258 do { \ 259 BUG_ON(!(__param_##name.perm & 0222)); \ 260 __kernel_param_unlock(); \ 261 } while (0) 262 263 /** 264 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 265 * @name: the name of the parameter 266 * 267 * This also blocks sysfs writes. 268 */ 269 #define kparam_block_sysfs_read(name) \ 270 do { \ 271 BUG_ON(!(__param_##name.perm & 0444)); \ 272 __kernel_param_lock(); \ 273 } while (0) 274 275 /** 276 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 277 * @name: the name of the parameter 278 */ 279 #define kparam_unblock_sysfs_read(name) \ 280 do { \ 281 BUG_ON(!(__param_##name.perm & 0444)); \ 282 __kernel_param_unlock(); \ 283 } while (0) 284 285 #ifdef CONFIG_SYSFS 286 extern void __kernel_param_lock(void); 287 extern void __kernel_param_unlock(void); 288 #else 289 static inline void __kernel_param_lock(void) 290 { 291 } 292 static inline void __kernel_param_unlock(void) 293 { 294 } 295 #endif 296 297 #ifndef MODULE 298 /** 299 * core_param - define a historical core kernel parameter. 300 * @name: the name of the cmdline and sysfs parameter (often the same as var) 301 * @var: the variable 302 * @type: the type of the parameter 303 * @perm: visibility in sysfs 304 * 305 * core_param is just like module_param(), but cannot be modular and 306 * doesn't add a prefix (such as "printk."). This is for compatibility 307 * with __setup(), and it makes sense as truly core parameters aren't 308 * tied to the particular file they're in. 309 */ 310 #define core_param(name, var, type, perm) \ 311 param_check_##type(name, &(var)); \ 312 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0) 313 314 /** 315 * core_param_unsafe - same as core_param but taints kernel 316 */ 317 #define core_param_unsafe(name, var, type, perm) \ 318 param_check_##type(name, &(var)); \ 319 __module_param_call("", name, ¶m_ops_##type, &var, perm, \ 320 -1, KERNEL_PARAM_FL_UNSAFE) 321 322 #endif /* !MODULE */ 323 324 /** 325 * module_param_string - a char array parameter 326 * @name: the name of the parameter 327 * @string: the string variable 328 * @len: the maximum length of the string, incl. terminator 329 * @perm: visibility in sysfs. 330 * 331 * This actually copies the string when it's set (unlike type charp). 332 * @len is usually just sizeof(string). 333 */ 334 #define module_param_string(name, string, len, perm) \ 335 static const struct kparam_string __param_string_##name \ 336 = { len, string }; \ 337 __module_param_call(MODULE_PARAM_PREFIX, name, \ 338 ¶m_ops_string, \ 339 .str = &__param_string_##name, perm, -1, 0);\ 340 __MODULE_PARM_TYPE(name, "string") 341 342 /** 343 * parameq - checks if two parameter names match 344 * @name1: parameter name 1 345 * @name2: parameter name 2 346 * 347 * Returns true if the two parameter names are equal. 348 * Dashes (-) are considered equal to underscores (_). 349 */ 350 extern bool parameq(const char *name1, const char *name2); 351 352 /** 353 * parameqn - checks if two parameter names match 354 * @name1: parameter name 1 355 * @name2: parameter name 2 356 * @n: the length to compare 357 * 358 * Similar to parameq(), except it compares @n characters. 359 */ 360 extern bool parameqn(const char *name1, const char *name2, size_t n); 361 362 /* Called on module insert or kernel boot */ 363 extern char *parse_args(const char *name, 364 char *args, 365 const struct kernel_param *params, 366 unsigned num, 367 s16 level_min, 368 s16 level_max, 369 void *arg, 370 int (*unknown)(char *param, char *val, 371 const char *doing, void *arg)); 372 373 /* Called by module remove. */ 374 #ifdef CONFIG_SYSFS 375 extern void destroy_params(const struct kernel_param *params, unsigned num); 376 #else 377 static inline void destroy_params(const struct kernel_param *params, 378 unsigned num) 379 { 380 } 381 #endif /* !CONFIG_SYSFS */ 382 383 /* All the helper functions */ 384 /* The macros to do compile-time type checking stolen from Jakub 385 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 386 #define __param_check(name, p, type) \ 387 static inline type __always_unused *__check_##name(void) { return(p); } 388 389 extern struct kernel_param_ops param_ops_byte; 390 extern int param_set_byte(const char *val, const struct kernel_param *kp); 391 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 392 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 393 394 extern struct kernel_param_ops param_ops_short; 395 extern int param_set_short(const char *val, const struct kernel_param *kp); 396 extern int param_get_short(char *buffer, const struct kernel_param *kp); 397 #define param_check_short(name, p) __param_check(name, p, short) 398 399 extern struct kernel_param_ops param_ops_ushort; 400 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 401 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 402 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 403 404 extern struct kernel_param_ops param_ops_int; 405 extern int param_set_int(const char *val, const struct kernel_param *kp); 406 extern int param_get_int(char *buffer, const struct kernel_param *kp); 407 #define param_check_int(name, p) __param_check(name, p, int) 408 409 extern struct kernel_param_ops param_ops_uint; 410 extern int param_set_uint(const char *val, const struct kernel_param *kp); 411 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 412 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 413 414 extern struct kernel_param_ops param_ops_long; 415 extern int param_set_long(const char *val, const struct kernel_param *kp); 416 extern int param_get_long(char *buffer, const struct kernel_param *kp); 417 #define param_check_long(name, p) __param_check(name, p, long) 418 419 extern struct kernel_param_ops param_ops_ulong; 420 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 421 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 422 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 423 424 extern struct kernel_param_ops param_ops_ullong; 425 extern int param_set_ullong(const char *val, const struct kernel_param *kp); 426 extern int param_get_ullong(char *buffer, const struct kernel_param *kp); 427 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long) 428 429 extern struct kernel_param_ops param_ops_charp; 430 extern int param_set_charp(const char *val, const struct kernel_param *kp); 431 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 432 #define param_check_charp(name, p) __param_check(name, p, char *) 433 434 /* We used to allow int as well as bool. We're taking that away! */ 435 extern struct kernel_param_ops param_ops_bool; 436 extern int param_set_bool(const char *val, const struct kernel_param *kp); 437 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 438 #define param_check_bool(name, p) __param_check(name, p, bool) 439 440 extern struct kernel_param_ops param_ops_invbool; 441 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 442 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 443 #define param_check_invbool(name, p) __param_check(name, p, bool) 444 445 /* An int, which can only be set like a bool (though it shows as an int). */ 446 extern struct kernel_param_ops param_ops_bint; 447 extern int param_set_bint(const char *val, const struct kernel_param *kp); 448 #define param_get_bint param_get_int 449 #define param_check_bint param_check_int 450 451 /** 452 * module_param_array - a parameter which is an array of some type 453 * @name: the name of the array variable 454 * @type: the type, as per module_param() 455 * @nump: optional pointer filled in with the number written 456 * @perm: visibility in sysfs 457 * 458 * Input and output are as comma-separated values. Commas inside values 459 * don't work properly (eg. an array of charp). 460 * 461 * ARRAY_SIZE(@name) is used to determine the number of elements in the 462 * array, so the definition must be visible. 463 */ 464 #define module_param_array(name, type, nump, perm) \ 465 module_param_array_named(name, name, type, nump, perm) 466 467 /** 468 * module_param_array_named - renamed parameter which is an array of some type 469 * @name: a valid C identifier which is the parameter name 470 * @array: the name of the array variable 471 * @type: the type, as per module_param() 472 * @nump: optional pointer filled in with the number written 473 * @perm: visibility in sysfs 474 * 475 * This exposes a different name than the actual variable name. See 476 * module_param_named() for why this might be necessary. 477 */ 478 #define module_param_array_named(name, array, type, nump, perm) \ 479 param_check_##type(name, &(array)[0]); \ 480 static const struct kparam_array __param_arr_##name \ 481 = { .max = ARRAY_SIZE(array), .num = nump, \ 482 .ops = ¶m_ops_##type, \ 483 .elemsize = sizeof(array[0]), .elem = array }; \ 484 __module_param_call(MODULE_PARAM_PREFIX, name, \ 485 ¶m_array_ops, \ 486 .arr = &__param_arr_##name, \ 487 perm, -1, 0); \ 488 __MODULE_PARM_TYPE(name, "array of " #type) 489 490 extern struct kernel_param_ops param_array_ops; 491 492 extern struct kernel_param_ops param_ops_string; 493 extern int param_set_copystring(const char *val, const struct kernel_param *); 494 extern int param_get_string(char *buffer, const struct kernel_param *kp); 495 496 /* for exporting parameters in /sys/module/.../parameters */ 497 498 struct module; 499 500 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 501 extern int module_param_sysfs_setup(struct module *mod, 502 const struct kernel_param *kparam, 503 unsigned int num_params); 504 505 extern void module_param_sysfs_remove(struct module *mod); 506 #else 507 static inline int module_param_sysfs_setup(struct module *mod, 508 const struct kernel_param *kparam, 509 unsigned int num_params) 510 { 511 return 0; 512 } 513 514 static inline void module_param_sysfs_remove(struct module *mod) 515 { } 516 #endif 517 518 #endif /* _LINUX_MODULE_PARAMS_H */ 519