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, (void *)set, (void *)get }; \ 234 __module_param_call(MODULE_PARAM_PREFIX, \ 235 name, &__param_ops_##name, arg, \ 236 (perm) + sizeof(__check_old_set_param(set))*0, -1, 0) 237 238 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 239 static inline int 240 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 241 { 242 return 0; 243 } 244 245 #ifdef CONFIG_SYSFS 246 extern void kernel_param_lock(struct module *mod); 247 extern void kernel_param_unlock(struct module *mod); 248 #else 249 static inline void kernel_param_lock(struct module *mod) 250 { 251 } 252 static inline void kernel_param_unlock(struct module *mod) 253 { 254 } 255 #endif 256 257 #ifndef MODULE 258 /** 259 * core_param - define a historical core kernel parameter. 260 * @name: the name of the cmdline and sysfs parameter (often the same as var) 261 * @var: the variable 262 * @type: the type of the parameter 263 * @perm: visibility in sysfs 264 * 265 * core_param is just like module_param(), but cannot be modular and 266 * doesn't add a prefix (such as "printk."). This is for compatibility 267 * with __setup(), and it makes sense as truly core parameters aren't 268 * tied to the particular file they're in. 269 */ 270 #define core_param(name, var, type, perm) \ 271 param_check_##type(name, &(var)); \ 272 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0) 273 274 /** 275 * core_param_unsafe - same as core_param but taints kernel 276 */ 277 #define core_param_unsafe(name, var, type, perm) \ 278 param_check_##type(name, &(var)); \ 279 __module_param_call("", name, ¶m_ops_##type, &var, perm, \ 280 -1, KERNEL_PARAM_FL_UNSAFE) 281 282 #endif /* !MODULE */ 283 284 /** 285 * module_param_string - a char array parameter 286 * @name: the name of the parameter 287 * @string: the string variable 288 * @len: the maximum length of the string, incl. terminator 289 * @perm: visibility in sysfs. 290 * 291 * This actually copies the string when it's set (unlike type charp). 292 * @len is usually just sizeof(string). 293 */ 294 #define module_param_string(name, string, len, perm) \ 295 static const struct kparam_string __param_string_##name \ 296 = { len, string }; \ 297 __module_param_call(MODULE_PARAM_PREFIX, name, \ 298 ¶m_ops_string, \ 299 .str = &__param_string_##name, perm, -1, 0);\ 300 __MODULE_PARM_TYPE(name, "string") 301 302 /** 303 * parameq - checks if two parameter names match 304 * @name1: parameter name 1 305 * @name2: parameter name 2 306 * 307 * Returns true if the two parameter names are equal. 308 * Dashes (-) are considered equal to underscores (_). 309 */ 310 extern bool parameq(const char *name1, const char *name2); 311 312 /** 313 * parameqn - checks if two parameter names match 314 * @name1: parameter name 1 315 * @name2: parameter name 2 316 * @n: the length to compare 317 * 318 * Similar to parameq(), except it compares @n characters. 319 */ 320 extern bool parameqn(const char *name1, const char *name2, size_t n); 321 322 /* Called on module insert or kernel boot */ 323 extern char *parse_args(const char *name, 324 char *args, 325 const struct kernel_param *params, 326 unsigned num, 327 s16 level_min, 328 s16 level_max, 329 void *arg, 330 int (*unknown)(char *param, char *val, 331 const char *doing, void *arg)); 332 333 /* Called by module remove. */ 334 #ifdef CONFIG_SYSFS 335 extern void destroy_params(const struct kernel_param *params, unsigned num); 336 #else 337 static inline void destroy_params(const struct kernel_param *params, 338 unsigned num) 339 { 340 } 341 #endif /* !CONFIG_SYSFS */ 342 343 /* All the helper functions */ 344 /* The macros to do compile-time type checking stolen from Jakub 345 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 346 #define __param_check(name, p, type) \ 347 static inline type __always_unused *__check_##name(void) { return(p); } 348 349 extern const struct kernel_param_ops param_ops_byte; 350 extern int param_set_byte(const char *val, const struct kernel_param *kp); 351 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 352 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 353 354 extern const struct kernel_param_ops param_ops_short; 355 extern int param_set_short(const char *val, const struct kernel_param *kp); 356 extern int param_get_short(char *buffer, const struct kernel_param *kp); 357 #define param_check_short(name, p) __param_check(name, p, short) 358 359 extern const struct kernel_param_ops param_ops_ushort; 360 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 361 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 362 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 363 364 extern const struct kernel_param_ops param_ops_int; 365 extern int param_set_int(const char *val, const struct kernel_param *kp); 366 extern int param_get_int(char *buffer, const struct kernel_param *kp); 367 #define param_check_int(name, p) __param_check(name, p, int) 368 369 extern const struct kernel_param_ops param_ops_uint; 370 extern int param_set_uint(const char *val, const struct kernel_param *kp); 371 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 372 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 373 374 extern const struct kernel_param_ops param_ops_long; 375 extern int param_set_long(const char *val, const struct kernel_param *kp); 376 extern int param_get_long(char *buffer, const struct kernel_param *kp); 377 #define param_check_long(name, p) __param_check(name, p, long) 378 379 extern const struct kernel_param_ops param_ops_ulong; 380 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 381 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 382 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 383 384 extern const struct kernel_param_ops param_ops_ullong; 385 extern int param_set_ullong(const char *val, const struct kernel_param *kp); 386 extern int param_get_ullong(char *buffer, const struct kernel_param *kp); 387 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long) 388 389 extern const struct kernel_param_ops param_ops_charp; 390 extern int param_set_charp(const char *val, const struct kernel_param *kp); 391 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 392 extern void param_free_charp(void *arg); 393 #define param_check_charp(name, p) __param_check(name, p, char *) 394 395 /* We used to allow int as well as bool. We're taking that away! */ 396 extern const struct kernel_param_ops param_ops_bool; 397 extern int param_set_bool(const char *val, const struct kernel_param *kp); 398 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 399 #define param_check_bool(name, p) __param_check(name, p, bool) 400 401 extern const struct kernel_param_ops param_ops_bool_enable_only; 402 extern int param_set_bool_enable_only(const char *val, 403 const struct kernel_param *kp); 404 /* getter is the same as for the regular bool */ 405 #define param_check_bool_enable_only param_check_bool 406 407 extern const struct kernel_param_ops param_ops_invbool; 408 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 409 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 410 #define param_check_invbool(name, p) __param_check(name, p, bool) 411 412 /* An int, which can only be set like a bool (though it shows as an int). */ 413 extern const struct kernel_param_ops param_ops_bint; 414 extern int param_set_bint(const char *val, const struct kernel_param *kp); 415 #define param_get_bint param_get_int 416 #define param_check_bint param_check_int 417 418 /** 419 * module_param_array - a parameter which is an array of some type 420 * @name: the name of the array variable 421 * @type: the type, as per module_param() 422 * @nump: optional pointer filled in with the number written 423 * @perm: visibility in sysfs 424 * 425 * Input and output are as comma-separated values. Commas inside values 426 * don't work properly (eg. an array of charp). 427 * 428 * ARRAY_SIZE(@name) is used to determine the number of elements in the 429 * array, so the definition must be visible. 430 */ 431 #define module_param_array(name, type, nump, perm) \ 432 module_param_array_named(name, name, type, nump, perm) 433 434 /** 435 * module_param_array_named - renamed parameter which is an array of some type 436 * @name: a valid C identifier which is the parameter name 437 * @array: the name of the array variable 438 * @type: the type, as per module_param() 439 * @nump: optional pointer filled in with the number written 440 * @perm: visibility in sysfs 441 * 442 * This exposes a different name than the actual variable name. See 443 * module_param_named() for why this might be necessary. 444 */ 445 #define module_param_array_named(name, array, type, nump, perm) \ 446 param_check_##type(name, &(array)[0]); \ 447 static const struct kparam_array __param_arr_##name \ 448 = { .max = ARRAY_SIZE(array), .num = nump, \ 449 .ops = ¶m_ops_##type, \ 450 .elemsize = sizeof(array[0]), .elem = array }; \ 451 __module_param_call(MODULE_PARAM_PREFIX, name, \ 452 ¶m_array_ops, \ 453 .arr = &__param_arr_##name, \ 454 perm, -1, 0); \ 455 __MODULE_PARM_TYPE(name, "array of " #type) 456 457 enum hwparam_type { 458 hwparam_ioport, /* Module parameter configures an I/O port */ 459 hwparam_iomem, /* Module parameter configures an I/O mem address */ 460 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */ 461 hwparam_irq, /* Module parameter configures an IRQ */ 462 hwparam_dma, /* Module parameter configures a DMA channel */ 463 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */ 464 hwparam_other, /* Module parameter configures some other value */ 465 }; 466 467 /** 468 * module_param_hw_named - A parameter representing a hw parameters 469 * @name: a valid C identifier which is the parameter name. 470 * @value: the actual lvalue to alter. 471 * @type: the type of the parameter 472 * @hwtype: what the value represents (enum hwparam_type) 473 * @perm: visibility in sysfs. 474 * 475 * Usually it's a good idea to have variable names and user-exposed names the 476 * same, but that's harder if the variable must be non-static or is inside a 477 * structure. This allows exposure under a different name. 478 */ 479 #define module_param_hw_named(name, value, type, hwtype, perm) \ 480 param_check_##type(name, &(value)); \ 481 __module_param_call(MODULE_PARAM_PREFIX, name, \ 482 ¶m_ops_##type, &value, \ 483 perm, -1, \ 484 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \ 485 __MODULE_PARM_TYPE(name, #type) 486 487 #define module_param_hw(name, type, hwtype, perm) \ 488 module_param_hw_named(name, name, type, hwtype, perm) 489 490 /** 491 * module_param_hw_array - A parameter representing an array of hw parameters 492 * @name: the name of the array variable 493 * @type: the type, as per module_param() 494 * @hwtype: what the value represents (enum hwparam_type) 495 * @nump: optional pointer filled in with the number written 496 * @perm: visibility in sysfs 497 * 498 * Input and output are as comma-separated values. Commas inside values 499 * don't work properly (eg. an array of charp). 500 * 501 * ARRAY_SIZE(@name) is used to determine the number of elements in the 502 * array, so the definition must be visible. 503 */ 504 #define module_param_hw_array(name, type, hwtype, nump, perm) \ 505 param_check_##type(name, &(name)[0]); \ 506 static const struct kparam_array __param_arr_##name \ 507 = { .max = ARRAY_SIZE(name), .num = nump, \ 508 .ops = ¶m_ops_##type, \ 509 .elemsize = sizeof(name[0]), .elem = name }; \ 510 __module_param_call(MODULE_PARAM_PREFIX, name, \ 511 ¶m_array_ops, \ 512 .arr = &__param_arr_##name, \ 513 perm, -1, \ 514 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \ 515 __MODULE_PARM_TYPE(name, "array of " #type) 516 517 518 extern const struct kernel_param_ops param_array_ops; 519 520 extern const struct kernel_param_ops param_ops_string; 521 extern int param_set_copystring(const char *val, const struct kernel_param *); 522 extern int param_get_string(char *buffer, const struct kernel_param *kp); 523 524 /* for exporting parameters in /sys/module/.../parameters */ 525 526 struct module; 527 528 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 529 extern int module_param_sysfs_setup(struct module *mod, 530 const struct kernel_param *kparam, 531 unsigned int num_params); 532 533 extern void module_param_sysfs_remove(struct module *mod); 534 #else 535 static inline int module_param_sysfs_setup(struct module *mod, 536 const struct kernel_param *kparam, 537 unsigned int num_params) 538 { 539 return 0; 540 } 541 542 static inline void module_param_sysfs_remove(struct module *mod) 543 { } 544 #endif 545 546 #endif /* _LINUX_MODULE_PARAMS_H */ 547