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 #define ___module_cat(a,b) __mod_ ## a ## b 20 #define __module_cat(a,b) ___module_cat(a,b) 21 #ifdef MODULE 22 #define __MODULE_INFO(tag, name, info) \ 23 static const char __module_cat(name,__LINE__)[] \ 24 __used __attribute__((section(".modinfo"), unused, aligned(1))) \ 25 = __stringify(tag) "=" info 26 #else /* !MODULE */ 27 /* This struct is here for syntactic coherency, it is not used */ 28 #define __MODULE_INFO(tag, name, info) \ 29 struct __module_cat(name,__LINE__) {} 30 #endif 31 #define __MODULE_PARM_TYPE(name, _type) \ 32 __MODULE_INFO(parmtype, name##type, #name ":" _type) 33 34 struct kernel_param; 35 36 struct kernel_param_ops { 37 /* Returns 0, or -errno. arg is in kp->arg. */ 38 int (*set)(const char *val, const struct kernel_param *kp); 39 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ 40 int (*get)(char *buffer, const struct kernel_param *kp); 41 /* Optional function to free kp->arg when module unloaded. */ 42 void (*free)(void *arg); 43 }; 44 45 /* Flag bits for kernel_param.flags */ 46 #define KPARAM_ISBOOL 2 47 48 struct kernel_param { 49 const char *name; 50 const struct kernel_param_ops *ops; 51 u16 perm; 52 u16 flags; 53 union { 54 void *arg; 55 const struct kparam_string *str; 56 const struct kparam_array *arr; 57 }; 58 }; 59 60 /* Special one for strings we want to copy into */ 61 struct kparam_string { 62 unsigned int maxlen; 63 char *string; 64 }; 65 66 /* Special one for arrays */ 67 struct kparam_array 68 { 69 unsigned int max; 70 unsigned int elemsize; 71 unsigned int *num; 72 const struct kernel_param_ops *ops; 73 void *elem; 74 }; 75 76 /** 77 * module_param - typesafe helper for a module/cmdline parameter 78 * @value: the variable to alter, and exposed parameter name. 79 * @type: the type of the parameter 80 * @perm: visibility in sysfs. 81 * 82 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 83 * ".") the kernel commandline parameter. Note that - is changed to _, so 84 * the user can use "foo-bar=1" even for variable "foo_bar". 85 * 86 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 87 * for world-readable, 0644 for root-writable, etc. Note that if it 88 * is writable, you may need to use kparam_block_sysfs_write() around 89 * accesses (esp. charp, which can be kfreed when it changes). 90 * 91 * The @type is simply pasted to refer to a param_ops_##type and a 92 * param_check_##type: for convenience many standard types are provided but 93 * you can create your own by defining those variables. 94 * 95 * Standard types are: 96 * byte, short, ushort, int, uint, long, ulong 97 * charp: a character pointer 98 * bool: a bool, values 0/1, y/n, Y/N. 99 * invbool: the above, only sense-reversed (N = true). 100 */ 101 #define module_param(name, type, perm) \ 102 module_param_named(name, name, type, perm) 103 104 /** 105 * module_param_named - typesafe helper for a renamed module/cmdline parameter 106 * @name: a valid C identifier which is the parameter name. 107 * @value: the actual lvalue to alter. 108 * @type: the type of the parameter 109 * @perm: visibility in sysfs. 110 * 111 * Usually it's a good idea to have variable names and user-exposed names the 112 * same, but that's harder if the variable must be non-static or is inside a 113 * structure. This allows exposure under a different name. 114 */ 115 #define module_param_named(name, value, type, perm) \ 116 param_check_##type(name, &(value)); \ 117 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 118 __MODULE_PARM_TYPE(name, #type) 119 120 /** 121 * module_param_cb - general callback for a module/cmdline parameter 122 * @name: a valid C identifier which is the parameter name. 123 * @ops: the set & get operations for this parameter. 124 * @perm: visibility in sysfs. 125 * 126 * The ops can have NULL set or get functions. 127 */ 128 #define module_param_cb(name, ops, arg, perm) \ 129 __module_param_call(MODULE_PARAM_PREFIX, \ 130 name, ops, arg, __same_type((arg), bool *), perm) 131 132 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 133 read-only sections (which is part of respective UNIX ABI on these 134 platforms). So 'const' makes no sense and even causes compile failures 135 with some compilers. */ 136 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 137 #define __moduleparam_const 138 #else 139 #define __moduleparam_const const 140 #endif 141 142 /* This is the fundamental function for registering boot/module 143 parameters. */ 144 #define __module_param_call(prefix, name, ops, arg, isbool, perm) \ 145 /* Default value instead of permissions? */ \ 146 static int __param_perm_check_##name __attribute__((unused)) = \ 147 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ 148 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \ 149 static const char __param_str_##name[] = prefix #name; \ 150 static struct kernel_param __moduleparam_const __param_##name \ 151 __used \ 152 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 153 = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \ 154 { arg } } 155 156 /* Obsolete - use module_param_cb() */ 157 #define module_param_call(name, set, get, arg, perm) \ 158 static struct kernel_param_ops __param_ops_##name = \ 159 { (void *)set, (void *)get }; \ 160 __module_param_call(MODULE_PARAM_PREFIX, \ 161 name, &__param_ops_##name, arg, \ 162 __same_type(arg, bool *), \ 163 (perm) + sizeof(__check_old_set_param(set))*0) 164 165 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 166 static inline int 167 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 168 { 169 return 0; 170 } 171 172 /** 173 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 174 * @name: the name of the parameter 175 * 176 * There's no point blocking write on a paramter that isn't writable via sysfs! 177 */ 178 #define kparam_block_sysfs_write(name) \ 179 do { \ 180 BUG_ON(!(__param_##name.perm & 0222)); \ 181 __kernel_param_lock(); \ 182 } while (0) 183 184 /** 185 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 186 * @name: the name of the parameter 187 */ 188 #define kparam_unblock_sysfs_write(name) \ 189 do { \ 190 BUG_ON(!(__param_##name.perm & 0222)); \ 191 __kernel_param_unlock(); \ 192 } while (0) 193 194 /** 195 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 196 * @name: the name of the parameter 197 * 198 * This also blocks sysfs writes. 199 */ 200 #define kparam_block_sysfs_read(name) \ 201 do { \ 202 BUG_ON(!(__param_##name.perm & 0444)); \ 203 __kernel_param_lock(); \ 204 } while (0) 205 206 /** 207 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 208 * @name: the name of the parameter 209 */ 210 #define kparam_unblock_sysfs_read(name) \ 211 do { \ 212 BUG_ON(!(__param_##name.perm & 0444)); \ 213 __kernel_param_unlock(); \ 214 } while (0) 215 216 #ifdef CONFIG_SYSFS 217 extern void __kernel_param_lock(void); 218 extern void __kernel_param_unlock(void); 219 #else 220 static inline void __kernel_param_lock(void) 221 { 222 } 223 static inline void __kernel_param_unlock(void) 224 { 225 } 226 #endif 227 228 #ifndef MODULE 229 /** 230 * core_param - define a historical core kernel parameter. 231 * @name: the name of the cmdline and sysfs parameter (often the same as var) 232 * @var: the variable 233 * @type: the type of the parameter 234 * @perm: visibility in sysfs 235 * 236 * core_param is just like module_param(), but cannot be modular and 237 * doesn't add a prefix (such as "printk."). This is for compatibility 238 * with __setup(), and it makes sense as truly core parameters aren't 239 * tied to the particular file they're in. 240 */ 241 #define core_param(name, var, type, perm) \ 242 param_check_##type(name, &(var)); \ 243 __module_param_call("", name, ¶m_ops_##type, \ 244 &var, __same_type(var, bool), perm) 245 #endif /* !MODULE */ 246 247 /** 248 * module_param_string - a char array parameter 249 * @name: the name of the parameter 250 * @string: the string variable 251 * @len: the maximum length of the string, incl. terminator 252 * @perm: visibility in sysfs. 253 * 254 * This actually copies the string when it's set (unlike type charp). 255 * @len is usually just sizeof(string). 256 */ 257 #define module_param_string(name, string, len, perm) \ 258 static const struct kparam_string __param_string_##name \ 259 = { len, string }; \ 260 __module_param_call(MODULE_PARAM_PREFIX, name, \ 261 ¶m_ops_string, \ 262 .str = &__param_string_##name, 0, perm); \ 263 __MODULE_PARM_TYPE(name, "string") 264 265 /** 266 * parameq - checks if two parameter names match 267 * @name1: parameter name 1 268 * @name2: parameter name 2 269 * 270 * Returns true if the two parameter names are equal. 271 * Dashes (-) are considered equal to underscores (_). 272 */ 273 extern bool parameq(const char *name1, const char *name2); 274 275 /** 276 * parameqn - checks if two parameter names match 277 * @name1: parameter name 1 278 * @name2: parameter name 2 279 * @n: the length to compare 280 * 281 * Similar to parameq(), except it compares @n characters. 282 */ 283 extern bool parameqn(const char *name1, const char *name2, size_t n); 284 285 /* Called on module insert or kernel boot */ 286 extern int parse_args(const char *name, 287 char *args, 288 const struct kernel_param *params, 289 unsigned num, 290 int (*unknown)(char *param, char *val)); 291 292 /* Called by module remove. */ 293 #ifdef CONFIG_SYSFS 294 extern void destroy_params(const struct kernel_param *params, unsigned num); 295 #else 296 static inline void destroy_params(const struct kernel_param *params, 297 unsigned num) 298 { 299 } 300 #endif /* !CONFIG_SYSFS */ 301 302 /* All the helper functions */ 303 /* The macros to do compile-time type checking stolen from Jakub 304 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 305 #define __param_check(name, p, type) \ 306 static inline type *__check_##name(void) { return(p); } 307 308 extern struct kernel_param_ops param_ops_byte; 309 extern int param_set_byte(const char *val, const struct kernel_param *kp); 310 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 311 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 312 313 extern struct kernel_param_ops param_ops_short; 314 extern int param_set_short(const char *val, const struct kernel_param *kp); 315 extern int param_get_short(char *buffer, const struct kernel_param *kp); 316 #define param_check_short(name, p) __param_check(name, p, short) 317 318 extern struct kernel_param_ops param_ops_ushort; 319 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 320 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 321 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 322 323 extern struct kernel_param_ops param_ops_int; 324 extern int param_set_int(const char *val, const struct kernel_param *kp); 325 extern int param_get_int(char *buffer, const struct kernel_param *kp); 326 #define param_check_int(name, p) __param_check(name, p, int) 327 328 extern struct kernel_param_ops param_ops_uint; 329 extern int param_set_uint(const char *val, const struct kernel_param *kp); 330 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 331 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 332 333 extern struct kernel_param_ops param_ops_long; 334 extern int param_set_long(const char *val, const struct kernel_param *kp); 335 extern int param_get_long(char *buffer, const struct kernel_param *kp); 336 #define param_check_long(name, p) __param_check(name, p, long) 337 338 extern struct kernel_param_ops param_ops_ulong; 339 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 340 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 341 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 342 343 extern struct kernel_param_ops param_ops_charp; 344 extern int param_set_charp(const char *val, const struct kernel_param *kp); 345 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 346 #define param_check_charp(name, p) __param_check(name, p, char *) 347 348 /* For historical reasons "bool" parameters can be (unsigned) "int". */ 349 extern struct kernel_param_ops param_ops_bool; 350 extern int param_set_bool(const char *val, const struct kernel_param *kp); 351 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 352 #define param_check_bool(name, p) \ 353 static inline void __check_##name(void) \ 354 { \ 355 BUILD_BUG_ON(!__same_type((p), bool *) && \ 356 !__same_type((p), unsigned int *) && \ 357 !__same_type((p), int *)); \ 358 } 359 360 extern struct kernel_param_ops param_ops_invbool; 361 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 362 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 363 #define param_check_invbool(name, p) __param_check(name, p, bool) 364 365 /** 366 * module_param_array - a parameter which is an array of some type 367 * @name: the name of the array variable 368 * @type: the type, as per module_param() 369 * @nump: optional pointer filled in with the number written 370 * @perm: visibility in sysfs 371 * 372 * Input and output are as comma-separated values. Commas inside values 373 * don't work properly (eg. an array of charp). 374 * 375 * ARRAY_SIZE(@name) is used to determine the number of elements in the 376 * array, so the definition must be visible. 377 */ 378 #define module_param_array(name, type, nump, perm) \ 379 module_param_array_named(name, name, type, nump, perm) 380 381 /** 382 * module_param_array_named - renamed parameter which is an array of some type 383 * @name: a valid C identifier which is the parameter name 384 * @array: the name of the array variable 385 * @type: the type, as per module_param() 386 * @nump: optional pointer filled in with the number written 387 * @perm: visibility in sysfs 388 * 389 * This exposes a different name than the actual variable name. See 390 * module_param_named() for why this might be necessary. 391 */ 392 #define module_param_array_named(name, array, type, nump, perm) \ 393 static const struct kparam_array __param_arr_##name \ 394 = { .max = ARRAY_SIZE(array), .num = nump, \ 395 .ops = ¶m_ops_##type, \ 396 .elemsize = sizeof(array[0]), .elem = array }; \ 397 __module_param_call(MODULE_PARAM_PREFIX, name, \ 398 ¶m_array_ops, \ 399 .arr = &__param_arr_##name, \ 400 __same_type(array[0], bool), perm); \ 401 __MODULE_PARM_TYPE(name, "array of " #type) 402 403 extern struct kernel_param_ops param_array_ops; 404 405 extern struct kernel_param_ops param_ops_string; 406 extern int param_set_copystring(const char *val, const struct kernel_param *); 407 extern int param_get_string(char *buffer, const struct kernel_param *kp); 408 409 /* for exporting parameters in /sys/parameters */ 410 411 struct module; 412 413 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 414 extern int module_param_sysfs_setup(struct module *mod, 415 const struct kernel_param *kparam, 416 unsigned int num_params); 417 418 extern void module_param_sysfs_remove(struct module *mod); 419 #else 420 static inline int module_param_sysfs_setup(struct module *mod, 421 const struct kernel_param *kparam, 422 unsigned int num_params) 423 { 424 return 0; 425 } 426 427 static inline void module_param_sysfs_remove(struct module *mod) 428 { } 429 #endif 430 431 #endif /* _LINUX_MODULE_PARAMS_H */ 432