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 #else 14 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "." 15 #endif 16 17 /* Chosen so that structs with an unsigned long line up. */ 18 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) 19 20 #ifdef MODULE 21 #define __MODULE_INFO(tag, name, info) \ 22 static const char __UNIQUE_ID(name)[] \ 23 __used __attribute__((section(".modinfo"), unused, aligned(1))) \ 24 = __stringify(tag) "=" info 25 #else /* !MODULE */ 26 /* This struct is here for syntactic coherency, it is not used */ 27 #define __MODULE_INFO(tag, name, info) \ 28 struct __UNIQUE_ID(name) {} 29 #endif 30 #define __MODULE_PARM_TYPE(name, _type) \ 31 __MODULE_INFO(parmtype, name##type, #name ":" _type) 32 33 /* One for each parameter, describing how to use it. Some files do 34 multiple of these per line, so can't just use MODULE_INFO. */ 35 #define MODULE_PARM_DESC(_parm, desc) \ 36 __MODULE_INFO(parm, _parm, #_parm ":" desc) 37 38 struct kernel_param; 39 40 /* 41 * Flags available for kernel_param_ops 42 * 43 * NOARG - the parameter allows for no argument (foo instead of foo=1) 44 */ 45 enum { 46 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0) 47 }; 48 49 struct kernel_param_ops { 50 /* How the ops should behave */ 51 unsigned int flags; 52 /* Returns 0, or -errno. arg is in kp->arg. */ 53 int (*set)(const char *val, const struct kernel_param *kp); 54 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ 55 int (*get)(char *buffer, const struct kernel_param *kp); 56 /* Optional function to free kp->arg when module unloaded. */ 57 void (*free)(void *arg); 58 }; 59 60 /* 61 * Flags available for kernel_param 62 * 63 * UNSAFE - the parameter is dangerous and setting it will taint the kernel 64 * HWPARAM - Hardware param not permitted in lockdown mode 65 */ 66 enum { 67 KERNEL_PARAM_FL_UNSAFE = (1 << 0), 68 KERNEL_PARAM_FL_HWPARAM = (1 << 1), 69 }; 70 71 struct kernel_param { 72 const char *name; 73 struct module *mod; 74 const struct kernel_param_ops *ops; 75 const u16 perm; 76 s8 level; 77 u8 flags; 78 union { 79 void *arg; 80 const struct kparam_string *str; 81 const struct kparam_array *arr; 82 }; 83 }; 84 85 extern const struct kernel_param __start___param[], __stop___param[]; 86 87 /* Special one for strings we want to copy into */ 88 struct kparam_string { 89 unsigned int maxlen; 90 char *string; 91 }; 92 93 /* Special one for arrays */ 94 struct kparam_array 95 { 96 unsigned int max; 97 unsigned int elemsize; 98 unsigned int *num; 99 const struct kernel_param_ops *ops; 100 void *elem; 101 }; 102 103 /** 104 * module_param - typesafe helper for a module/cmdline parameter 105 * @value: the variable to alter, and exposed parameter name. 106 * @type: the type of the parameter 107 * @perm: visibility in sysfs. 108 * 109 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 110 * ".") the kernel commandline parameter. Note that - is changed to _, so 111 * the user can use "foo-bar=1" even for variable "foo_bar". 112 * 113 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 114 * for world-readable, 0644 for root-writable, etc. Note that if it 115 * is writable, you may need to use kernel_param_lock() around 116 * accesses (esp. charp, which can be kfreed when it changes). 117 * 118 * The @type is simply pasted to refer to a param_ops_##type and a 119 * param_check_##type: for convenience many standard types are provided but 120 * you can create your own by defining those variables. 121 * 122 * Standard types are: 123 * byte, short, ushort, int, uint, long, ulong 124 * charp: a character pointer 125 * bool: a bool, values 0/1, y/n, Y/N. 126 * invbool: the above, only sense-reversed (N = true). 127 */ 128 #define module_param(name, type, perm) \ 129 module_param_named(name, name, type, perm) 130 131 /** 132 * module_param_unsafe - same as module_param but taints kernel 133 */ 134 #define module_param_unsafe(name, type, perm) \ 135 module_param_named_unsafe(name, name, type, perm) 136 137 /** 138 * module_param_named - typesafe helper for a renamed module/cmdline parameter 139 * @name: a valid C identifier which is the parameter name. 140 * @value: the actual lvalue to alter. 141 * @type: the type of the parameter 142 * @perm: visibility in sysfs. 143 * 144 * Usually it's a good idea to have variable names and user-exposed names the 145 * same, but that's harder if the variable must be non-static or is inside a 146 * structure. This allows exposure under a different name. 147 */ 148 #define module_param_named(name, value, type, perm) \ 149 param_check_##type(name, &(value)); \ 150 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 151 __MODULE_PARM_TYPE(name, #type) 152 153 /** 154 * module_param_named_unsafe - same as module_param_named but taints kernel 155 */ 156 #define module_param_named_unsafe(name, value, type, perm) \ 157 param_check_##type(name, &(value)); \ 158 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \ 159 __MODULE_PARM_TYPE(name, #type) 160 161 /** 162 * module_param_cb - general callback for a module/cmdline parameter 163 * @name: a valid C identifier which is the parameter name. 164 * @ops: the set & get operations for this parameter. 165 * @perm: visibility in sysfs. 166 * 167 * The ops can have NULL set or get functions. 168 */ 169 #define module_param_cb(name, ops, arg, perm) \ 170 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0) 171 172 #define module_param_cb_unsafe(name, ops, arg, perm) \ 173 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \ 174 KERNEL_PARAM_FL_UNSAFE) 175 176 /** 177 * <level>_param_cb - general callback for a module/cmdline parameter 178 * to be evaluated before certain initcall level 179 * @name: a valid C identifier which is the parameter name. 180 * @ops: the set & get operations for this parameter. 181 * @perm: visibility in sysfs. 182 * 183 * The ops can have NULL set or get functions. 184 */ 185 #define __level_param_cb(name, ops, arg, perm, level) \ 186 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0) 187 188 #define core_param_cb(name, ops, arg, perm) \ 189 __level_param_cb(name, ops, arg, perm, 1) 190 191 #define postcore_param_cb(name, ops, arg, perm) \ 192 __level_param_cb(name, ops, arg, perm, 2) 193 194 #define arch_param_cb(name, ops, arg, perm) \ 195 __level_param_cb(name, ops, arg, perm, 3) 196 197 #define subsys_param_cb(name, ops, arg, perm) \ 198 __level_param_cb(name, ops, arg, perm, 4) 199 200 #define fs_param_cb(name, ops, arg, perm) \ 201 __level_param_cb(name, ops, arg, perm, 5) 202 203 #define device_param_cb(name, ops, arg, perm) \ 204 __level_param_cb(name, ops, arg, perm, 6) 205 206 #define late_param_cb(name, ops, arg, perm) \ 207 __level_param_cb(name, ops, arg, perm, 7) 208 209 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 210 read-only sections (which is part of respective UNIX ABI on these 211 platforms). So 'const' makes no sense and even causes compile failures 212 with some compilers. */ 213 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 214 #define __moduleparam_const 215 #else 216 #define __moduleparam_const const 217 #endif 218 219 /* This is the fundamental function for registering boot/module 220 parameters. */ 221 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \ 222 /* Default value instead of permissions? */ \ 223 static const char __param_str_##name[] = prefix #name; \ 224 static struct kernel_param __moduleparam_const __param_##name \ 225 __used \ 226 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 227 = { __param_str_##name, THIS_MODULE, ops, \ 228 VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } } 229 230 /* Obsolete - use module_param_cb() */ 231 #define module_param_call(name, _set, _get, arg, perm) \ 232 static const struct kernel_param_ops __param_ops_##name = \ 233 { .flags = 0, .set = _set, .get = _get }; \ 234 __module_param_call(MODULE_PARAM_PREFIX, \ 235 name, &__param_ops_##name, arg, perm, -1, 0) 236 237 #ifdef CONFIG_SYSFS 238 extern void kernel_param_lock(struct module *mod); 239 extern void kernel_param_unlock(struct module *mod); 240 #else 241 static inline void kernel_param_lock(struct module *mod) 242 { 243 } 244 static inline void kernel_param_unlock(struct module *mod) 245 { 246 } 247 #endif 248 249 #ifndef MODULE 250 /** 251 * core_param - define a historical core kernel parameter. 252 * @name: the name of the cmdline and sysfs parameter (often the same as var) 253 * @var: the variable 254 * @type: the type of the parameter 255 * @perm: visibility in sysfs 256 * 257 * core_param is just like module_param(), but cannot be modular and 258 * doesn't add a prefix (such as "printk."). This is for compatibility 259 * with __setup(), and it makes sense as truly core parameters aren't 260 * tied to the particular file they're in. 261 */ 262 #define core_param(name, var, type, perm) \ 263 param_check_##type(name, &(var)); \ 264 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0) 265 266 /** 267 * core_param_unsafe - same as core_param but taints kernel 268 */ 269 #define core_param_unsafe(name, var, type, perm) \ 270 param_check_##type(name, &(var)); \ 271 __module_param_call("", name, ¶m_ops_##type, &var, perm, \ 272 -1, KERNEL_PARAM_FL_UNSAFE) 273 274 #endif /* !MODULE */ 275 276 /** 277 * module_param_string - a char array parameter 278 * @name: the name of the parameter 279 * @string: the string variable 280 * @len: the maximum length of the string, incl. terminator 281 * @perm: visibility in sysfs. 282 * 283 * This actually copies the string when it's set (unlike type charp). 284 * @len is usually just sizeof(string). 285 */ 286 #define module_param_string(name, string, len, perm) \ 287 static const struct kparam_string __param_string_##name \ 288 = { len, string }; \ 289 __module_param_call(MODULE_PARAM_PREFIX, name, \ 290 ¶m_ops_string, \ 291 .str = &__param_string_##name, perm, -1, 0);\ 292 __MODULE_PARM_TYPE(name, "string") 293 294 /** 295 * parameq - checks if two parameter names match 296 * @name1: parameter name 1 297 * @name2: parameter name 2 298 * 299 * Returns true if the two parameter names are equal. 300 * Dashes (-) are considered equal to underscores (_). 301 */ 302 extern bool parameq(const char *name1, const char *name2); 303 304 /** 305 * parameqn - checks if two parameter names match 306 * @name1: parameter name 1 307 * @name2: parameter name 2 308 * @n: the length to compare 309 * 310 * Similar to parameq(), except it compares @n characters. 311 */ 312 extern bool parameqn(const char *name1, const char *name2, size_t n); 313 314 /* Called on module insert or kernel boot */ 315 extern char *parse_args(const char *name, 316 char *args, 317 const struct kernel_param *params, 318 unsigned num, 319 s16 level_min, 320 s16 level_max, 321 void *arg, 322 int (*unknown)(char *param, char *val, 323 const char *doing, void *arg)); 324 325 /* Called by module remove. */ 326 #ifdef CONFIG_SYSFS 327 extern void destroy_params(const struct kernel_param *params, unsigned num); 328 #else 329 static inline void destroy_params(const struct kernel_param *params, 330 unsigned num) 331 { 332 } 333 #endif /* !CONFIG_SYSFS */ 334 335 /* All the helper functions */ 336 /* The macros to do compile-time type checking stolen from Jakub 337 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 338 #define __param_check(name, p, type) \ 339 static inline type __always_unused *__check_##name(void) { return(p); } 340 341 extern const struct kernel_param_ops param_ops_byte; 342 extern int param_set_byte(const char *val, const struct kernel_param *kp); 343 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 344 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 345 346 extern const struct kernel_param_ops param_ops_short; 347 extern int param_set_short(const char *val, const struct kernel_param *kp); 348 extern int param_get_short(char *buffer, const struct kernel_param *kp); 349 #define param_check_short(name, p) __param_check(name, p, short) 350 351 extern const struct kernel_param_ops param_ops_ushort; 352 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 353 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 354 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 355 356 extern const struct kernel_param_ops param_ops_int; 357 extern int param_set_int(const char *val, const struct kernel_param *kp); 358 extern int param_get_int(char *buffer, const struct kernel_param *kp); 359 #define param_check_int(name, p) __param_check(name, p, int) 360 361 extern const struct kernel_param_ops param_ops_uint; 362 extern int param_set_uint(const char *val, const struct kernel_param *kp); 363 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 364 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 365 366 extern const struct kernel_param_ops param_ops_long; 367 extern int param_set_long(const char *val, const struct kernel_param *kp); 368 extern int param_get_long(char *buffer, const struct kernel_param *kp); 369 #define param_check_long(name, p) __param_check(name, p, long) 370 371 extern const struct kernel_param_ops param_ops_ulong; 372 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 373 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 374 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 375 376 extern const struct kernel_param_ops param_ops_ullong; 377 extern int param_set_ullong(const char *val, const struct kernel_param *kp); 378 extern int param_get_ullong(char *buffer, const struct kernel_param *kp); 379 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long) 380 381 extern const struct kernel_param_ops param_ops_charp; 382 extern int param_set_charp(const char *val, const struct kernel_param *kp); 383 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 384 extern void param_free_charp(void *arg); 385 #define param_check_charp(name, p) __param_check(name, p, char *) 386 387 /* We used to allow int as well as bool. We're taking that away! */ 388 extern const struct kernel_param_ops param_ops_bool; 389 extern int param_set_bool(const char *val, const struct kernel_param *kp); 390 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 391 #define param_check_bool(name, p) __param_check(name, p, bool) 392 393 extern const struct kernel_param_ops param_ops_bool_enable_only; 394 extern int param_set_bool_enable_only(const char *val, 395 const struct kernel_param *kp); 396 /* getter is the same as for the regular bool */ 397 #define param_check_bool_enable_only param_check_bool 398 399 extern const struct kernel_param_ops param_ops_invbool; 400 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 401 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 402 #define param_check_invbool(name, p) __param_check(name, p, bool) 403 404 /* An int, which can only be set like a bool (though it shows as an int). */ 405 extern const struct kernel_param_ops param_ops_bint; 406 extern int param_set_bint(const char *val, const struct kernel_param *kp); 407 #define param_get_bint param_get_int 408 #define param_check_bint param_check_int 409 410 /** 411 * module_param_array - a parameter which is an array of some type 412 * @name: the name of the array variable 413 * @type: the type, as per module_param() 414 * @nump: optional pointer filled in with the number written 415 * @perm: visibility in sysfs 416 * 417 * Input and output are as comma-separated values. Commas inside values 418 * don't work properly (eg. an array of charp). 419 * 420 * ARRAY_SIZE(@name) is used to determine the number of elements in the 421 * array, so the definition must be visible. 422 */ 423 #define module_param_array(name, type, nump, perm) \ 424 module_param_array_named(name, name, type, nump, perm) 425 426 /** 427 * module_param_array_named - renamed parameter which is an array of some type 428 * @name: a valid C identifier which is the parameter name 429 * @array: the name of the array variable 430 * @type: the type, as per module_param() 431 * @nump: optional pointer filled in with the number written 432 * @perm: visibility in sysfs 433 * 434 * This exposes a different name than the actual variable name. See 435 * module_param_named() for why this might be necessary. 436 */ 437 #define module_param_array_named(name, array, type, nump, perm) \ 438 param_check_##type(name, &(array)[0]); \ 439 static const struct kparam_array __param_arr_##name \ 440 = { .max = ARRAY_SIZE(array), .num = nump, \ 441 .ops = ¶m_ops_##type, \ 442 .elemsize = sizeof(array[0]), .elem = array }; \ 443 __module_param_call(MODULE_PARAM_PREFIX, name, \ 444 ¶m_array_ops, \ 445 .arr = &__param_arr_##name, \ 446 perm, -1, 0); \ 447 __MODULE_PARM_TYPE(name, "array of " #type) 448 449 enum hwparam_type { 450 hwparam_ioport, /* Module parameter configures an I/O port */ 451 hwparam_iomem, /* Module parameter configures an I/O mem address */ 452 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */ 453 hwparam_irq, /* Module parameter configures an IRQ */ 454 hwparam_dma, /* Module parameter configures a DMA channel */ 455 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */ 456 hwparam_other, /* Module parameter configures some other value */ 457 }; 458 459 /** 460 * module_param_hw_named - A parameter representing a hw parameters 461 * @name: a valid C identifier which is the parameter name. 462 * @value: the actual lvalue to alter. 463 * @type: the type of the parameter 464 * @hwtype: what the value represents (enum hwparam_type) 465 * @perm: visibility in sysfs. 466 * 467 * Usually it's a good idea to have variable names and user-exposed names the 468 * same, but that's harder if the variable must be non-static or is inside a 469 * structure. This allows exposure under a different name. 470 */ 471 #define module_param_hw_named(name, value, type, hwtype, perm) \ 472 param_check_##type(name, &(value)); \ 473 __module_param_call(MODULE_PARAM_PREFIX, name, \ 474 ¶m_ops_##type, &value, \ 475 perm, -1, \ 476 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \ 477 __MODULE_PARM_TYPE(name, #type) 478 479 #define module_param_hw(name, type, hwtype, perm) \ 480 module_param_hw_named(name, name, type, hwtype, perm) 481 482 /** 483 * module_param_hw_array - A parameter representing an array of hw parameters 484 * @name: the name of the array variable 485 * @type: the type, as per module_param() 486 * @hwtype: what the value represents (enum hwparam_type) 487 * @nump: optional pointer filled in with the number written 488 * @perm: visibility in sysfs 489 * 490 * Input and output are as comma-separated values. Commas inside values 491 * don't work properly (eg. an array of charp). 492 * 493 * ARRAY_SIZE(@name) is used to determine the number of elements in the 494 * array, so the definition must be visible. 495 */ 496 #define module_param_hw_array(name, type, hwtype, nump, perm) \ 497 param_check_##type(name, &(name)[0]); \ 498 static const struct kparam_array __param_arr_##name \ 499 = { .max = ARRAY_SIZE(name), .num = nump, \ 500 .ops = ¶m_ops_##type, \ 501 .elemsize = sizeof(name[0]), .elem = name }; \ 502 __module_param_call(MODULE_PARAM_PREFIX, name, \ 503 ¶m_array_ops, \ 504 .arr = &__param_arr_##name, \ 505 perm, -1, \ 506 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \ 507 __MODULE_PARM_TYPE(name, "array of " #type) 508 509 510 extern const struct kernel_param_ops param_array_ops; 511 512 extern const struct kernel_param_ops param_ops_string; 513 extern int param_set_copystring(const char *val, const struct kernel_param *); 514 extern int param_get_string(char *buffer, const struct kernel_param *kp); 515 516 /* for exporting parameters in /sys/module/.../parameters */ 517 518 struct module; 519 520 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 521 extern int module_param_sysfs_setup(struct module *mod, 522 const struct kernel_param *kparam, 523 unsigned int num_params); 524 525 extern void module_param_sysfs_remove(struct module *mod); 526 #else 527 static inline int module_param_sysfs_setup(struct module *mod, 528 const struct kernel_param *kparam, 529 unsigned int num_params) 530 { 531 return 0; 532 } 533 534 static inline void module_param_sysfs_remove(struct module *mod) 535 { } 536 #endif 537 538 #endif /* _LINUX_MODULE_PARAMS_H */ 539