1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_MODULE_PARAMS_H 3 #define _LINUX_MODULE_PARAMS_H 4 /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */ 5 #include <linux/init.h> 6 #include <linux/stringify.h> 7 #include <linux/kernel.h> 8 9 /* You can override this manually, but generally this should match the 10 module name. */ 11 #ifdef MODULE 12 #define MODULE_PARAM_PREFIX /* empty */ 13 #define __MODULE_INFO_PREFIX /* empty */ 14 #else 15 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "." 16 /* We cannot use MODULE_PARAM_PREFIX because some modules override it. */ 17 #define __MODULE_INFO_PREFIX KBUILD_MODNAME "." 18 #endif 19 20 /* Chosen so that structs with an unsigned long line up. */ 21 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) 22 23 #define __MODULE_INFO(tag, name, info) \ 24 static const char __UNIQUE_ID(name)[] \ 25 __used __attribute__((section(".modinfo"), unused, aligned(1))) \ 26 = __MODULE_INFO_PREFIX __stringify(tag) "=" info 27 28 #define __MODULE_PARM_TYPE(name, _type) \ 29 __MODULE_INFO(parmtype, name##type, #name ":" _type) 30 31 /* One for each parameter, describing how to use it. Some files do 32 multiple of these per line, so can't just use MODULE_INFO. */ 33 #define MODULE_PARM_DESC(_parm, desc) \ 34 __MODULE_INFO(parm, _parm, #_parm ":" desc) 35 36 struct kernel_param; 37 38 /* 39 * Flags available for kernel_param_ops 40 * 41 * NOARG - the parameter allows for no argument (foo instead of foo=1) 42 */ 43 enum { 44 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0) 45 }; 46 47 struct kernel_param_ops { 48 /* How the ops should behave */ 49 unsigned int flags; 50 /* Returns 0, or -errno. arg is in kp->arg. */ 51 int (*set)(const char *val, const struct kernel_param *kp); 52 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ 53 int (*get)(char *buffer, const struct kernel_param *kp); 54 /* Optional function to free kp->arg when module unloaded. */ 55 void (*free)(void *arg); 56 }; 57 58 /* 59 * Flags available for kernel_param 60 * 61 * UNSAFE - the parameter is dangerous and setting it will taint the kernel 62 * HWPARAM - Hardware param not permitted in lockdown mode 63 */ 64 enum { 65 KERNEL_PARAM_FL_UNSAFE = (1 << 0), 66 KERNEL_PARAM_FL_HWPARAM = (1 << 1), 67 }; 68 69 struct kernel_param { 70 const char *name; 71 struct module *mod; 72 const struct kernel_param_ops *ops; 73 const u16 perm; 74 s8 level; 75 u8 flags; 76 union { 77 void *arg; 78 const struct kparam_string *str; 79 const struct kparam_array *arr; 80 }; 81 }; 82 83 extern const struct kernel_param __start___param[], __stop___param[]; 84 85 /* Special one for strings we want to copy into */ 86 struct kparam_string { 87 unsigned int maxlen; 88 char *string; 89 }; 90 91 /* Special one for arrays */ 92 struct kparam_array 93 { 94 unsigned int max; 95 unsigned int elemsize; 96 unsigned int *num; 97 const struct kernel_param_ops *ops; 98 void *elem; 99 }; 100 101 /** 102 * module_param - typesafe helper for a module/cmdline parameter 103 * @value: the variable to alter, and exposed parameter name. 104 * @type: the type of the parameter 105 * @perm: visibility in sysfs. 106 * 107 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 108 * ".") the kernel commandline parameter. Note that - is changed to _, so 109 * the user can use "foo-bar=1" even for variable "foo_bar". 110 * 111 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 112 * for world-readable, 0644 for root-writable, etc. Note that if it 113 * is writable, you may need to use kernel_param_lock() around 114 * accesses (esp. charp, which can be kfreed when it changes). 115 * 116 * The @type is simply pasted to refer to a param_ops_##type and a 117 * param_check_##type: for convenience many standard types are provided but 118 * you can create your own by defining those variables. 119 * 120 * Standard types are: 121 * byte, short, ushort, int, uint, long, ulong 122 * charp: a character pointer 123 * bool: a bool, values 0/1, y/n, Y/N. 124 * invbool: the above, only sense-reversed (N = true). 125 */ 126 #define module_param(name, type, perm) \ 127 module_param_named(name, name, type, perm) 128 129 /** 130 * module_param_unsafe - same as module_param but taints kernel 131 */ 132 #define module_param_unsafe(name, type, perm) \ 133 module_param_named_unsafe(name, name, type, perm) 134 135 /** 136 * module_param_named - typesafe helper for a renamed module/cmdline parameter 137 * @name: a valid C identifier which is the parameter name. 138 * @value: the actual lvalue to alter. 139 * @type: the type of the parameter 140 * @perm: visibility in sysfs. 141 * 142 * Usually it's a good idea to have variable names and user-exposed names the 143 * same, but that's harder if the variable must be non-static or is inside a 144 * structure. This allows exposure under a different name. 145 */ 146 #define module_param_named(name, value, type, perm) \ 147 param_check_##type(name, &(value)); \ 148 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 149 __MODULE_PARM_TYPE(name, #type) 150 151 /** 152 * module_param_named_unsafe - same as module_param_named but taints kernel 153 */ 154 #define module_param_named_unsafe(name, value, type, perm) \ 155 param_check_##type(name, &(value)); \ 156 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \ 157 __MODULE_PARM_TYPE(name, #type) 158 159 /** 160 * module_param_cb - general callback for a module/cmdline parameter 161 * @name: a valid C identifier which is the parameter name. 162 * @ops: the set & get operations for this parameter. 163 * @perm: visibility in sysfs. 164 * 165 * The ops can have NULL set or get functions. 166 */ 167 #define module_param_cb(name, ops, arg, perm) \ 168 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0) 169 170 #define module_param_cb_unsafe(name, ops, arg, perm) \ 171 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \ 172 KERNEL_PARAM_FL_UNSAFE) 173 174 /** 175 * <level>_param_cb - general callback for a module/cmdline parameter 176 * to be evaluated before certain initcall level 177 * @name: a valid C identifier which is the parameter name. 178 * @ops: the set & get operations for this parameter. 179 * @perm: visibility in sysfs. 180 * 181 * The ops can have NULL set or get functions. 182 */ 183 #define __level_param_cb(name, ops, arg, perm, level) \ 184 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0) 185 186 #define core_param_cb(name, ops, arg, perm) \ 187 __level_param_cb(name, ops, arg, perm, 1) 188 189 #define postcore_param_cb(name, ops, arg, perm) \ 190 __level_param_cb(name, ops, arg, perm, 2) 191 192 #define arch_param_cb(name, ops, arg, perm) \ 193 __level_param_cb(name, ops, arg, perm, 3) 194 195 #define subsys_param_cb(name, ops, arg, perm) \ 196 __level_param_cb(name, ops, arg, perm, 4) 197 198 #define fs_param_cb(name, ops, arg, perm) \ 199 __level_param_cb(name, ops, arg, perm, 5) 200 201 #define device_param_cb(name, ops, arg, perm) \ 202 __level_param_cb(name, ops, arg, perm, 6) 203 204 #define late_param_cb(name, ops, arg, perm) \ 205 __level_param_cb(name, ops, arg, perm, 7) 206 207 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 208 read-only sections (which is part of respective UNIX ABI on these 209 platforms). So 'const' makes no sense and even causes compile failures 210 with some compilers. */ 211 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 212 #define __moduleparam_const 213 #else 214 #define __moduleparam_const const 215 #endif 216 217 /* This is the fundamental function for registering boot/module 218 parameters. */ 219 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \ 220 /* Default value instead of permissions? */ \ 221 static const char __param_str_##name[] = prefix #name; \ 222 static struct kernel_param __moduleparam_const __param_##name \ 223 __used \ 224 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 225 = { __param_str_##name, THIS_MODULE, ops, \ 226 VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } } 227 228 /* Obsolete - use module_param_cb() */ 229 #define module_param_call(name, _set, _get, arg, perm) \ 230 static const struct kernel_param_ops __param_ops_##name = \ 231 { .flags = 0, .set = _set, .get = _get }; \ 232 __module_param_call(MODULE_PARAM_PREFIX, \ 233 name, &__param_ops_##name, arg, perm, -1, 0) 234 235 #ifdef CONFIG_SYSFS 236 extern void kernel_param_lock(struct module *mod); 237 extern void kernel_param_unlock(struct module *mod); 238 #else kernel_param_lock(struct module * mod)239 static inline void kernel_param_lock(struct module *mod) 240 { 241 } kernel_param_unlock(struct module * mod)242 static inline void kernel_param_unlock(struct module *mod) 243 { 244 } 245 #endif 246 247 #ifndef MODULE 248 /** 249 * core_param - define a historical core kernel parameter. 250 * @name: the name of the cmdline and sysfs parameter (often the same as var) 251 * @var: the variable 252 * @type: the type of the parameter 253 * @perm: visibility in sysfs 254 * 255 * core_param is just like module_param(), but cannot be modular and 256 * doesn't add a prefix (such as "printk."). This is for compatibility 257 * with __setup(), and it makes sense as truly core parameters aren't 258 * tied to the particular file they're in. 259 */ 260 #define core_param(name, var, type, perm) \ 261 param_check_##type(name, &(var)); \ 262 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0) 263 264 /** 265 * core_param_unsafe - same as core_param but taints kernel 266 */ 267 #define core_param_unsafe(name, var, type, perm) \ 268 param_check_##type(name, &(var)); \ 269 __module_param_call("", name, ¶m_ops_##type, &var, perm, \ 270 -1, KERNEL_PARAM_FL_UNSAFE) 271 272 #endif /* !MODULE */ 273 274 /** 275 * module_param_string - a char array parameter 276 * @name: the name of the parameter 277 * @string: the string variable 278 * @len: the maximum length of the string, incl. terminator 279 * @perm: visibility in sysfs. 280 * 281 * This actually copies the string when it's set (unlike type charp). 282 * @len is usually just sizeof(string). 283 */ 284 #define module_param_string(name, string, len, perm) \ 285 static const struct kparam_string __param_string_##name \ 286 = { len, string }; \ 287 __module_param_call(MODULE_PARAM_PREFIX, name, \ 288 ¶m_ops_string, \ 289 .str = &__param_string_##name, perm, -1, 0);\ 290 __MODULE_PARM_TYPE(name, "string") 291 292 /** 293 * parameq - checks if two parameter names match 294 * @name1: parameter name 1 295 * @name2: parameter name 2 296 * 297 * Returns true if the two parameter names are equal. 298 * Dashes (-) are considered equal to underscores (_). 299 */ 300 extern bool parameq(const char *name1, const char *name2); 301 302 /** 303 * parameqn - checks if two parameter names match 304 * @name1: parameter name 1 305 * @name2: parameter name 2 306 * @n: the length to compare 307 * 308 * Similar to parameq(), except it compares @n characters. 309 */ 310 extern bool parameqn(const char *name1, const char *name2, size_t n); 311 312 /* Called on module insert or kernel boot */ 313 extern char *parse_args(const char *name, 314 char *args, 315 const struct kernel_param *params, 316 unsigned num, 317 s16 level_min, 318 s16 level_max, 319 void *arg, 320 int (*unknown)(char *param, char *val, 321 const char *doing, void *arg)); 322 323 /* Called by module remove. */ 324 #ifdef CONFIG_SYSFS 325 extern void destroy_params(const struct kernel_param *params, unsigned num); 326 #else destroy_params(const struct kernel_param * params,unsigned num)327 static inline void destroy_params(const struct kernel_param *params, 328 unsigned num) 329 { 330 } 331 #endif /* !CONFIG_SYSFS */ 332 333 /* All the helper functions */ 334 /* The macros to do compile-time type checking stolen from Jakub 335 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 336 #define __param_check(name, p, type) \ 337 static inline type __always_unused *__check_##name(void) { return(p); } 338 339 extern const struct kernel_param_ops param_ops_byte; 340 extern int param_set_byte(const char *val, const struct kernel_param *kp); 341 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 342 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 343 344 extern const struct kernel_param_ops param_ops_short; 345 extern int param_set_short(const char *val, const struct kernel_param *kp); 346 extern int param_get_short(char *buffer, const struct kernel_param *kp); 347 #define param_check_short(name, p) __param_check(name, p, short) 348 349 extern const struct kernel_param_ops param_ops_ushort; 350 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 351 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 352 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 353 354 extern const struct kernel_param_ops param_ops_int; 355 extern int param_set_int(const char *val, const struct kernel_param *kp); 356 extern int param_get_int(char *buffer, const struct kernel_param *kp); 357 #define param_check_int(name, p) __param_check(name, p, int) 358 359 extern const struct kernel_param_ops param_ops_uint; 360 extern int param_set_uint(const char *val, const struct kernel_param *kp); 361 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 362 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 363 364 extern const struct kernel_param_ops param_ops_long; 365 extern int param_set_long(const char *val, const struct kernel_param *kp); 366 extern int param_get_long(char *buffer, const struct kernel_param *kp); 367 #define param_check_long(name, p) __param_check(name, p, long) 368 369 extern const struct kernel_param_ops param_ops_ulong; 370 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 371 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 372 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 373 374 extern const struct kernel_param_ops param_ops_ullong; 375 extern int param_set_ullong(const char *val, const struct kernel_param *kp); 376 extern int param_get_ullong(char *buffer, const struct kernel_param *kp); 377 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long) 378 379 extern const struct kernel_param_ops param_ops_charp; 380 extern int param_set_charp(const char *val, const struct kernel_param *kp); 381 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 382 extern void param_free_charp(void *arg); 383 #define param_check_charp(name, p) __param_check(name, p, char *) 384 385 /* We used to allow int as well as bool. We're taking that away! */ 386 extern const struct kernel_param_ops param_ops_bool; 387 extern int param_set_bool(const char *val, const struct kernel_param *kp); 388 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 389 #define param_check_bool(name, p) __param_check(name, p, bool) 390 391 extern const struct kernel_param_ops param_ops_bool_enable_only; 392 extern int param_set_bool_enable_only(const char *val, 393 const struct kernel_param *kp); 394 /* getter is the same as for the regular bool */ 395 #define param_check_bool_enable_only param_check_bool 396 397 extern const struct kernel_param_ops param_ops_invbool; 398 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 399 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 400 #define param_check_invbool(name, p) __param_check(name, p, bool) 401 402 /* An int, which can only be set like a bool (though it shows as an int). */ 403 extern const struct kernel_param_ops param_ops_bint; 404 extern int param_set_bint(const char *val, const struct kernel_param *kp); 405 #define param_get_bint param_get_int 406 #define param_check_bint param_check_int 407 408 /** 409 * module_param_array - a parameter which is an array of some type 410 * @name: the name of the array variable 411 * @type: the type, as per module_param() 412 * @nump: optional pointer filled in with the number written 413 * @perm: visibility in sysfs 414 * 415 * Input and output are as comma-separated values. Commas inside values 416 * don't work properly (eg. an array of charp). 417 * 418 * ARRAY_SIZE(@name) is used to determine the number of elements in the 419 * array, so the definition must be visible. 420 */ 421 #define module_param_array(name, type, nump, perm) \ 422 module_param_array_named(name, name, type, nump, perm) 423 424 /** 425 * module_param_array_named - renamed parameter which is an array of some type 426 * @name: a valid C identifier which is the parameter name 427 * @array: the name of the array variable 428 * @type: the type, as per module_param() 429 * @nump: optional pointer filled in with the number written 430 * @perm: visibility in sysfs 431 * 432 * This exposes a different name than the actual variable name. See 433 * module_param_named() for why this might be necessary. 434 */ 435 #define module_param_array_named(name, array, type, nump, perm) \ 436 param_check_##type(name, &(array)[0]); \ 437 static const struct kparam_array __param_arr_##name \ 438 = { .max = ARRAY_SIZE(array), .num = nump, \ 439 .ops = ¶m_ops_##type, \ 440 .elemsize = sizeof(array[0]), .elem = array }; \ 441 __module_param_call(MODULE_PARAM_PREFIX, name, \ 442 ¶m_array_ops, \ 443 .arr = &__param_arr_##name, \ 444 perm, -1, 0); \ 445 __MODULE_PARM_TYPE(name, "array of " #type) 446 447 enum hwparam_type { 448 hwparam_ioport, /* Module parameter configures an I/O port */ 449 hwparam_iomem, /* Module parameter configures an I/O mem address */ 450 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */ 451 hwparam_irq, /* Module parameter configures an IRQ */ 452 hwparam_dma, /* Module parameter configures a DMA channel */ 453 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */ 454 hwparam_other, /* Module parameter configures some other value */ 455 }; 456 457 /** 458 * module_param_hw_named - A parameter representing a hw parameters 459 * @name: a valid C identifier which is the parameter name. 460 * @value: the actual lvalue to alter. 461 * @type: the type of the parameter 462 * @hwtype: what the value represents (enum hwparam_type) 463 * @perm: visibility in sysfs. 464 * 465 * Usually it's a good idea to have variable names and user-exposed names the 466 * same, but that's harder if the variable must be non-static or is inside a 467 * structure. This allows exposure under a different name. 468 */ 469 #define module_param_hw_named(name, value, type, hwtype, perm) \ 470 param_check_##type(name, &(value)); \ 471 __module_param_call(MODULE_PARAM_PREFIX, name, \ 472 ¶m_ops_##type, &value, \ 473 perm, -1, \ 474 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \ 475 __MODULE_PARM_TYPE(name, #type) 476 477 #define module_param_hw(name, type, hwtype, perm) \ 478 module_param_hw_named(name, name, type, hwtype, perm) 479 480 /** 481 * module_param_hw_array - A parameter representing an array of hw parameters 482 * @name: the name of the array variable 483 * @type: the type, as per module_param() 484 * @hwtype: what the value represents (enum hwparam_type) 485 * @nump: optional pointer filled in with the number written 486 * @perm: visibility in sysfs 487 * 488 * Input and output are as comma-separated values. Commas inside values 489 * don't work properly (eg. an array of charp). 490 * 491 * ARRAY_SIZE(@name) is used to determine the number of elements in the 492 * array, so the definition must be visible. 493 */ 494 #define module_param_hw_array(name, type, hwtype, nump, perm) \ 495 param_check_##type(name, &(name)[0]); \ 496 static const struct kparam_array __param_arr_##name \ 497 = { .max = ARRAY_SIZE(name), .num = nump, \ 498 .ops = ¶m_ops_##type, \ 499 .elemsize = sizeof(name[0]), .elem = name }; \ 500 __module_param_call(MODULE_PARAM_PREFIX, name, \ 501 ¶m_array_ops, \ 502 .arr = &__param_arr_##name, \ 503 perm, -1, \ 504 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \ 505 __MODULE_PARM_TYPE(name, "array of " #type) 506 507 508 extern const struct kernel_param_ops param_array_ops; 509 510 extern const struct kernel_param_ops param_ops_string; 511 extern int param_set_copystring(const char *val, const struct kernel_param *); 512 extern int param_get_string(char *buffer, const struct kernel_param *kp); 513 514 /* for exporting parameters in /sys/module/.../parameters */ 515 516 struct module; 517 518 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 519 extern int module_param_sysfs_setup(struct module *mod, 520 const struct kernel_param *kparam, 521 unsigned int num_params); 522 523 extern void module_param_sysfs_remove(struct module *mod); 524 #else module_param_sysfs_setup(struct module * mod,const struct kernel_param * kparam,unsigned int num_params)525 static inline int module_param_sysfs_setup(struct module *mod, 526 const struct kernel_param *kparam, 527 unsigned int num_params) 528 { 529 return 0; 530 } 531 module_param_sysfs_remove(struct module * mod)532 static inline void module_param_sysfs_remove(struct module *mod) 533 { } 534 #endif 535 536 #endif /* _LINUX_MODULE_PARAMS_H */ 537