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