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