moduleparam.h 16 KB

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  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. /* You can override this manually, but generally this should match the
  8. module name. */
  9. #ifdef MODULE
  10. #define MODULE_PARAM_PREFIX /* empty */
  11. #else
  12. #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
  13. #endif
  14. /* Chosen so that structs with an unsigned long line up. */
  15. #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
  16. #define ___module_cat(a,b) __mod_ ## a ## b
  17. #define __module_cat(a,b) ___module_cat(a,b)
  18. #ifdef MODULE
  19. #define __MODULE_INFO(tag, name, info) \
  20. static const char __module_cat(name,__LINE__)[] \
  21. __used __attribute__((section(".modinfo"), unused, aligned(1))) \
  22. = __stringify(tag) "=" info
  23. #else /* !MODULE */
  24. /* This struct is here for syntactic coherency, it is not used */
  25. #define __MODULE_INFO(tag, name, info) \
  26. struct __module_cat(name,__LINE__) {}
  27. #endif
  28. #define __MODULE_PARM_TYPE(name, _type) \
  29. __MODULE_INFO(parmtype, name##type, #name ":" _type)
  30. /* One for each parameter, describing how to use it. Some files do
  31. multiple of these per line, so can't just use MODULE_INFO. */
  32. #define MODULE_PARM_DESC(_parm, desc) \
  33. __MODULE_INFO(parm, _parm, #_parm ":" desc)
  34. struct kernel_param;
  35. struct kernel_param_ops {
  36. /* Returns 0, or -errno. arg is in kp->arg. */
  37. int (*set)(const char *val, const struct kernel_param *kp);
  38. /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
  39. int (*get)(char *buffer, const struct kernel_param *kp);
  40. /* Optional function to free kp->arg when module unloaded. */
  41. void (*free)(void *arg);
  42. };
  43. struct kernel_param {
  44. const char *name;
  45. const struct kernel_param_ops *ops;
  46. u16 perm;
  47. s16 level;
  48. union {
  49. void *arg;
  50. const struct kparam_string *str;
  51. const struct kparam_array *arr;
  52. };
  53. };
  54. /* Special one for strings we want to copy into */
  55. struct kparam_string {
  56. unsigned int maxlen;
  57. char *string;
  58. };
  59. /* Special one for arrays */
  60. struct kparam_array
  61. {
  62. unsigned int max;
  63. unsigned int elemsize;
  64. unsigned int *num;
  65. const struct kernel_param_ops *ops;
  66. void *elem;
  67. };
  68. /**
  69. * module_param - typesafe helper for a module/cmdline parameter
  70. * @value: the variable to alter, and exposed parameter name.
  71. * @type: the type of the parameter
  72. * @perm: visibility in sysfs.
  73. *
  74. * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
  75. * ".") the kernel commandline parameter. Note that - is changed to _, so
  76. * the user can use "foo-bar=1" even for variable "foo_bar".
  77. *
  78. * @perm is 0 if the the variable is not to appear in sysfs, or 0444
  79. * for world-readable, 0644 for root-writable, etc. Note that if it
  80. * is writable, you may need to use kparam_block_sysfs_write() around
  81. * accesses (esp. charp, which can be kfreed when it changes).
  82. *
  83. * The @type is simply pasted to refer to a param_ops_##type and a
  84. * param_check_##type: for convenience many standard types are provided but
  85. * you can create your own by defining those variables.
  86. *
  87. * Standard types are:
  88. * byte, short, ushort, int, uint, long, ulong
  89. * charp: a character pointer
  90. * bool: a bool, values 0/1, y/n, Y/N.
  91. * invbool: the above, only sense-reversed (N = true).
  92. */
  93. #define module_param(name, type, perm) \
  94. module_param_named(name, name, type, perm)
  95. /**
  96. * module_param_named - typesafe helper for a renamed module/cmdline parameter
  97. * @name: a valid C identifier which is the parameter name.
  98. * @value: the actual lvalue to alter.
  99. * @type: the type of the parameter
  100. * @perm: visibility in sysfs.
  101. *
  102. * Usually it's a good idea to have variable names and user-exposed names the
  103. * same, but that's harder if the variable must be non-static or is inside a
  104. * structure. This allows exposure under a different name.
  105. */
  106. #define module_param_named(name, value, type, perm) \
  107. param_check_##type(name, &(value)); \
  108. module_param_cb(name, &param_ops_##type, &value, perm); \
  109. __MODULE_PARM_TYPE(name, #type)
  110. /**
  111. * module_param_cb - general callback for a module/cmdline parameter
  112. * @name: a valid C identifier which is the parameter name.
  113. * @ops: the set & get operations for this parameter.
  114. * @perm: visibility in sysfs.
  115. *
  116. * The ops can have NULL set or get functions.
  117. */
  118. #define module_param_cb(name, ops, arg, perm) \
  119. __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1)
  120. /**
  121. * <level>_param_cb - general callback for a module/cmdline parameter
  122. * to be evaluated before certain initcall level
  123. * @name: a valid C identifier which is the parameter name.
  124. * @ops: the set & get operations for this parameter.
  125. * @perm: visibility in sysfs.
  126. *
  127. * The ops can have NULL set or get functions.
  128. */
  129. #define __level_param_cb(name, ops, arg, perm, level) \
  130. __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level)
  131. #define core_param_cb(name, ops, arg, perm) \
  132. __level_param_cb(name, ops, arg, perm, 1)
  133. #define postcore_param_cb(name, ops, arg, perm) \
  134. __level_param_cb(name, ops, arg, perm, 2)
  135. #define arch_param_cb(name, ops, arg, perm) \
  136. __level_param_cb(name, ops, arg, perm, 3)
  137. #define subsys_param_cb(name, ops, arg, perm) \
  138. __level_param_cb(name, ops, arg, perm, 4)
  139. #define fs_param_cb(name, ops, arg, perm) \
  140. __level_param_cb(name, ops, arg, perm, 5)
  141. #define device_param_cb(name, ops, arg, perm) \
  142. __level_param_cb(name, ops, arg, perm, 6)
  143. #define late_param_cb(name, ops, arg, perm) \
  144. __level_param_cb(name, ops, arg, perm, 7)
  145. /* On alpha, ia64 and ppc64 relocations to global data cannot go into
  146. read-only sections (which is part of respective UNIX ABI on these
  147. platforms). So 'const' makes no sense and even causes compile failures
  148. with some compilers. */
  149. #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
  150. #define __moduleparam_const
  151. #else
  152. #define __moduleparam_const const
  153. #endif
  154. /* This is the fundamental function for registering boot/module
  155. parameters. */
  156. #define __module_param_call(prefix, name, ops, arg, perm, level) \
  157. /* Default value instead of permissions? */ \
  158. static int __param_perm_check_##name __attribute__((unused)) = \
  159. BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
  160. + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
  161. static const char __param_str_##name[] = prefix #name; \
  162. static struct kernel_param __moduleparam_const __param_##name \
  163. __used \
  164. __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
  165. = { __param_str_##name, ops, perm, level, { arg } }
  166. /* Obsolete - use module_param_cb() */
  167. #define module_param_call(name, set, get, arg, perm) \
  168. static struct kernel_param_ops __param_ops_##name = \
  169. { (void *)set, (void *)get }; \
  170. __module_param_call(MODULE_PARAM_PREFIX, \
  171. name, &__param_ops_##name, arg, \
  172. (perm) + sizeof(__check_old_set_param(set))*0, -1)
  173. /* We don't get oldget: it's often a new-style param_get_uint, etc. */
  174. static inline int
  175. __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
  176. {
  177. return 0;
  178. }
  179. /**
  180. * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
  181. * @name: the name of the parameter
  182. *
  183. * There's no point blocking write on a paramter that isn't writable via sysfs!
  184. */
  185. #define kparam_block_sysfs_write(name) \
  186. do { \
  187. BUG_ON(!(__param_##name.perm & 0222)); \
  188. __kernel_param_lock(); \
  189. } while (0)
  190. /**
  191. * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
  192. * @name: the name of the parameter
  193. */
  194. #define kparam_unblock_sysfs_write(name) \
  195. do { \
  196. BUG_ON(!(__param_##name.perm & 0222)); \
  197. __kernel_param_unlock(); \
  198. } while (0)
  199. /**
  200. * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
  201. * @name: the name of the parameter
  202. *
  203. * This also blocks sysfs writes.
  204. */
  205. #define kparam_block_sysfs_read(name) \
  206. do { \
  207. BUG_ON(!(__param_##name.perm & 0444)); \
  208. __kernel_param_lock(); \
  209. } while (0)
  210. /**
  211. * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
  212. * @name: the name of the parameter
  213. */
  214. #define kparam_unblock_sysfs_read(name) \
  215. do { \
  216. BUG_ON(!(__param_##name.perm & 0444)); \
  217. __kernel_param_unlock(); \
  218. } while (0)
  219. #ifdef CONFIG_SYSFS
  220. extern void __kernel_param_lock(void);
  221. extern void __kernel_param_unlock(void);
  222. #else
  223. static inline void __kernel_param_lock(void)
  224. {
  225. }
  226. static inline void __kernel_param_unlock(void)
  227. {
  228. }
  229. #endif
  230. #ifndef MODULE
  231. /**
  232. * core_param - define a historical core kernel parameter.
  233. * @name: the name of the cmdline and sysfs parameter (often the same as var)
  234. * @var: the variable
  235. * @type: the type of the parameter
  236. * @perm: visibility in sysfs
  237. *
  238. * core_param is just like module_param(), but cannot be modular and
  239. * doesn't add a prefix (such as "printk."). This is for compatibility
  240. * with __setup(), and it makes sense as truly core parameters aren't
  241. * tied to the particular file they're in.
  242. */
  243. #define core_param(name, var, type, perm) \
  244. param_check_##type(name, &(var)); \
  245. __module_param_call("", name, &param_ops_##type, &var, perm, -1)
  246. #endif /* !MODULE */
  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. &param_ops_string, \
  262. .str = &__param_string_##name, perm, -1); \
  263. __MODULE_PARM_TYPE(name, "string")
  264. /**
  265. * parameq - checks if two parameter names match
  266. * @name1: parameter name 1
  267. * @name2: parameter name 2
  268. *
  269. * Returns true if the two parameter names are equal.
  270. * Dashes (-) are considered equal to underscores (_).
  271. */
  272. extern bool parameq(const char *name1, const char *name2);
  273. /**
  274. * parameqn - checks if two parameter names match
  275. * @name1: parameter name 1
  276. * @name2: parameter name 2
  277. * @n: the length to compare
  278. *
  279. * Similar to parameq(), except it compares @n characters.
  280. */
  281. extern bool parameqn(const char *name1, const char *name2, size_t n);
  282. /* Called on module insert or kernel boot */
  283. extern int parse_args(const char *name,
  284. char *args,
  285. const struct kernel_param *params,
  286. unsigned num,
  287. s16 level_min,
  288. s16 level_max,
  289. int (*unknown)(char *param, char *val));
  290. /* Called by module remove. */
  291. #ifdef CONFIG_SYSFS
  292. extern void destroy_params(const struct kernel_param *params, unsigned num);
  293. #else
  294. static inline void destroy_params(const struct kernel_param *params,
  295. unsigned num)
  296. {
  297. }
  298. #endif /* !CONFIG_SYSFS */
  299. /* All the helper functions */
  300. /* The macros to do compile-time type checking stolen from Jakub
  301. Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
  302. #define __param_check(name, p, type) \
  303. static inline type __always_unused *__check_##name(void) { return(p); }
  304. extern struct kernel_param_ops param_ops_byte;
  305. extern int param_set_byte(const char *val, const struct kernel_param *kp);
  306. extern int param_get_byte(char *buffer, const struct kernel_param *kp);
  307. #define param_check_byte(name, p) __param_check(name, p, unsigned char)
  308. extern struct kernel_param_ops param_ops_short;
  309. extern int param_set_short(const char *val, const struct kernel_param *kp);
  310. extern int param_get_short(char *buffer, const struct kernel_param *kp);
  311. #define param_check_short(name, p) __param_check(name, p, short)
  312. extern struct kernel_param_ops param_ops_ushort;
  313. extern int param_set_ushort(const char *val, const struct kernel_param *kp);
  314. extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
  315. #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
  316. extern struct kernel_param_ops param_ops_int;
  317. extern int param_set_int(const char *val, const struct kernel_param *kp);
  318. extern int param_get_int(char *buffer, const struct kernel_param *kp);
  319. #define param_check_int(name, p) __param_check(name, p, int)
  320. extern struct kernel_param_ops param_ops_uint;
  321. extern int param_set_uint(const char *val, const struct kernel_param *kp);
  322. extern int param_get_uint(char *buffer, const struct kernel_param *kp);
  323. #define param_check_uint(name, p) __param_check(name, p, unsigned int)
  324. extern struct kernel_param_ops param_ops_long;
  325. extern int param_set_long(const char *val, const struct kernel_param *kp);
  326. extern int param_get_long(char *buffer, const struct kernel_param *kp);
  327. #define param_check_long(name, p) __param_check(name, p, long)
  328. extern struct kernel_param_ops param_ops_ulong;
  329. extern int param_set_ulong(const char *val, const struct kernel_param *kp);
  330. extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
  331. #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
  332. extern struct kernel_param_ops param_ops_charp;
  333. extern int param_set_charp(const char *val, const struct kernel_param *kp);
  334. extern int param_get_charp(char *buffer, const struct kernel_param *kp);
  335. #define param_check_charp(name, p) __param_check(name, p, char *)
  336. /* We used to allow int as well as bool. We're taking that away! */
  337. extern struct kernel_param_ops param_ops_bool;
  338. extern int param_set_bool(const char *val, const struct kernel_param *kp);
  339. extern int param_get_bool(char *buffer, const struct kernel_param *kp);
  340. #define param_check_bool(name, p) __param_check(name, p, bool)
  341. extern struct kernel_param_ops param_ops_invbool;
  342. extern int param_set_invbool(const char *val, const struct kernel_param *kp);
  343. extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
  344. #define param_check_invbool(name, p) __param_check(name, p, bool)
  345. /* An int, which can only be set like a bool (though it shows as an int). */
  346. extern struct kernel_param_ops param_ops_bint;
  347. extern int param_set_bint(const char *val, const struct kernel_param *kp);
  348. #define param_get_bint param_get_int
  349. #define param_check_bint param_check_int
  350. /**
  351. * module_param_array - a parameter which is an array of some type
  352. * @name: the name of the array variable
  353. * @type: the type, as per module_param()
  354. * @nump: optional pointer filled in with the number written
  355. * @perm: visibility in sysfs
  356. *
  357. * Input and output are as comma-separated values. Commas inside values
  358. * don't work properly (eg. an array of charp).
  359. *
  360. * ARRAY_SIZE(@name) is used to determine the number of elements in the
  361. * array, so the definition must be visible.
  362. */
  363. #define module_param_array(name, type, nump, perm) \
  364. module_param_array_named(name, name, type, nump, perm)
  365. /**
  366. * module_param_array_named - renamed parameter which is an array of some type
  367. * @name: a valid C identifier which is the parameter name
  368. * @array: the name of the array variable
  369. * @type: the type, as per module_param()
  370. * @nump: optional pointer filled in with the number written
  371. * @perm: visibility in sysfs
  372. *
  373. * This exposes a different name than the actual variable name. See
  374. * module_param_named() for why this might be necessary.
  375. */
  376. #define module_param_array_named(name, array, type, nump, perm) \
  377. param_check_##type(name, &(array)[0]); \
  378. static const struct kparam_array __param_arr_##name \
  379. = { .max = ARRAY_SIZE(array), .num = nump, \
  380. .ops = &param_ops_##type, \
  381. .elemsize = sizeof(array[0]), .elem = array }; \
  382. __module_param_call(MODULE_PARAM_PREFIX, name, \
  383. &param_array_ops, \
  384. .arr = &__param_arr_##name, \
  385. perm, -1); \
  386. __MODULE_PARM_TYPE(name, "array of " #type)
  387. extern struct kernel_param_ops param_array_ops;
  388. extern struct kernel_param_ops param_ops_string;
  389. extern int param_set_copystring(const char *val, const struct kernel_param *);
  390. extern int param_get_string(char *buffer, const struct kernel_param *kp);
  391. /* for exporting parameters in /sys/parameters */
  392. struct module;
  393. #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
  394. extern int module_param_sysfs_setup(struct module *mod,
  395. const struct kernel_param *kparam,
  396. unsigned int num_params);
  397. extern void module_param_sysfs_remove(struct module *mod);
  398. #else
  399. static inline int module_param_sysfs_setup(struct module *mod,
  400. const struct kernel_param *kparam,
  401. unsigned int num_params)
  402. {
  403. return 0;
  404. }
  405. static inline void module_param_sysfs_remove(struct module *mod)
  406. { }
  407. #endif
  408. #endif /* _LINUX_MODULE_PARAMS_H */