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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
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_INFO(tag, name, info) \
21 static const char __UNIQUE_ID(name)[] \
22 __used __attribute__((section(".modinfo"), unused, aligned(1))) \
23 = __stringify(tag) "=" info
24 #else /* !MODULE */
25 /* This struct is here for syntactic coherency, it is not used */
26 #define __MODULE_INFO(tag, name, info) \
27 struct __UNIQUE_ID(name) {}
28 #endif
29 #define __MODULE_PARM_TYPE(name, _type) \
30 __MODULE_INFO(parmtype, name##type, #name ":" _type)
31
32 /* One for each parameter, describing how to use it. Some files do
33 multiple of these per line, so can't just use MODULE_INFO. */
34 #define MODULE_PARM_DESC(_parm, desc) \
35 __MODULE_INFO(parm, _parm, #_parm ":" desc)
36
37 struct kernel_param;
38
39 /*
40 * Flags available for kernel_param_ops
41 *
42 * NOARG - the parameter allows for no argument (foo instead of foo=1)
43 */
44 enum {
45 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
46 };
47
48 struct kernel_param_ops {
49 /* How the ops should behave */
50 unsigned int flags;
51 /* Returns 0, or -errno. arg is in kp->arg. */
52 int (*set)(const char *val, const struct kernel_param *kp);
53 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
54 int (*get)(char *buffer, const struct kernel_param *kp);
55 /* Optional function to free kp->arg when module unloaded. */
56 void (*free)(void *arg);
57 };
58
59 /*
60 * Flags available for kernel_param
61 *
62 * UNSAFE - the parameter is dangerous and setting it will taint the kernel
63 */
64 enum {
65 KERNEL_PARAM_FL_UNSAFE = (1 << 0)
66 };
67
68 struct kernel_param {
69 const char *name;
70 const struct kernel_param_ops *ops;
71 u16 perm;
72 s8 level;
73 u8 flags;
74 union {
75 void *arg;
76 const struct kparam_string *str;
77 const struct kparam_array *arr;
78 };
79 };
80
81 extern const struct kernel_param __start___param[], __stop___param[];
82
83 /* Special one for strings we want to copy into */
84 struct kparam_string {
85 unsigned int maxlen;
86 char *string;
87 };
88
89 /* Special one for arrays */
90 struct kparam_array
91 {
92 unsigned int max;
93 unsigned int elemsize;
94 unsigned int *num;
95 const struct kernel_param_ops *ops;
96 void *elem;
97 };
98
99 /**
100 * module_param - typesafe helper for a module/cmdline parameter
101 * @value: the variable to alter, and exposed parameter name.
102 * @type: the type of the parameter
103 * @perm: visibility in sysfs.
104 *
105 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
106 * ".") the kernel commandline parameter. Note that - is changed to _, so
107 * the user can use "foo-bar=1" even for variable "foo_bar".
108 *
109 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
110 * for world-readable, 0644 for root-writable, etc. Note that if it
111 * is writable, you may need to use kparam_block_sysfs_write() around
112 * accesses (esp. charp, which can be kfreed when it changes).
113 *
114 * The @type is simply pasted to refer to a param_ops_##type and a
115 * param_check_##type: for convenience many standard types are provided but
116 * you can create your own by defining those variables.
117 *
118 * Standard types are:
119 * byte, short, ushort, int, uint, long, ulong
120 * charp: a character pointer
121 * bool: a bool, values 0/1, y/n, Y/N.
122 * invbool: the above, only sense-reversed (N = true).
123 */
124 #define module_param(name, type, perm) \
125 module_param_named(name, name, type, perm)
126
127 /**
128 * module_param_unsafe - same as module_param but taints kernel
129 */
130 #define module_param_unsafe(name, type, perm) \
131 module_param_named_unsafe(name, name, type, perm)
132
133 /**
134 * module_param_named - typesafe helper for a renamed module/cmdline parameter
135 * @name: a valid C identifier which is the parameter name.
136 * @value: the actual lvalue to alter.
137 * @type: the type of the parameter
138 * @perm: visibility in sysfs.
139 *
140 * Usually it's a good idea to have variable names and user-exposed names the
141 * same, but that's harder if the variable must be non-static or is inside a
142 * structure. This allows exposure under a different name.
143 */
144 #define module_param_named(name, value, type, perm) \
145 param_check_##type(name, &(value)); \
146 module_param_cb(name, &param_ops_##type, &value, perm); \
147 __MODULE_PARM_TYPE(name, #type)
148
149 /**
150 * module_param_named_unsafe - same as module_param_named but taints kernel
151 */
152 #define module_param_named_unsafe(name, value, type, perm) \
153 param_check_##type(name, &(value)); \
154 module_param_cb_unsafe(name, &param_ops_##type, &value, perm); \
155 __MODULE_PARM_TYPE(name, #type)
156
157 /**
158 * module_param_cb - general callback for a module/cmdline parameter
159 * @name: a valid C identifier which is the parameter name.
160 * @ops: the set & get operations for this parameter.
161 * @perm: visibility in sysfs.
162 *
163 * The ops can have NULL set or get functions.
164 */
165 #define module_param_cb(name, ops, arg, perm) \
166 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
167
168 #define module_param_cb_unsafe(name, ops, arg, perm) \
169 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \
170 KERNEL_PARAM_FL_UNSAFE)
171
172 /**
173 * <level>_param_cb - general callback for a module/cmdline parameter
174 * to be evaluated before certain initcall level
175 * @name: a valid C identifier which is the parameter name.
176 * @ops: the set & get operations for this parameter.
177 * @perm: visibility in sysfs.
178 *
179 * The ops can have NULL set or get functions.
180 */
181 #define __level_param_cb(name, ops, arg, perm, level) \
182 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
183
184 #define core_param_cb(name, ops, arg, perm) \
185 __level_param_cb(name, ops, arg, perm, 1)
186
187 #define postcore_param_cb(name, ops, arg, perm) \
188 __level_param_cb(name, ops, arg, perm, 2)
189
190 #define arch_param_cb(name, ops, arg, perm) \
191 __level_param_cb(name, ops, arg, perm, 3)
192
193 #define subsys_param_cb(name, ops, arg, perm) \
194 __level_param_cb(name, ops, arg, perm, 4)
195
196 #define fs_param_cb(name, ops, arg, perm) \
197 __level_param_cb(name, ops, arg, perm, 5)
198
199 #define device_param_cb(name, ops, arg, perm) \
200 __level_param_cb(name, ops, arg, perm, 6)
201
202 #define late_param_cb(name, ops, arg, perm) \
203 __level_param_cb(name, ops, arg, perm, 7)
204
205 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
206 read-only sections (which is part of respective UNIX ABI on these
207 platforms). So 'const' makes no sense and even causes compile failures
208 with some compilers. */
209 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
210 #define __moduleparam_const
211 #else
212 #define __moduleparam_const const
213 #endif
214
215 /* This is the fundamental function for registering boot/module
216 parameters. */
217 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
218 /* Default value instead of permissions? */ \
219 static const char __param_str_##name[] = prefix #name; \
220 static struct kernel_param __moduleparam_const __param_##name \
221 __used \
222 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
223 = { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \
224 level, flags, { arg } }
225
226 /* Obsolete - use module_param_cb() */
227 #define module_param_call(name, set, get, arg, perm) \
228 static struct kernel_param_ops __param_ops_##name = \
229 { .flags = 0, (void *)set, (void *)get }; \
230 __module_param_call(MODULE_PARAM_PREFIX, \
231 name, &__param_ops_##name, arg, \
232 (perm) + sizeof(__check_old_set_param(set))*0, -1, 0)
233
234 /* We don't get oldget: it's often a new-style param_get_uint, etc. */
235 static inline int
236 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
237 {
238 return 0;
239 }
240
241 /**
242 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
243 * @name: the name of the parameter
244 *
245 * There's no point blocking write on a paramter that isn't writable via sysfs!
246 */
247 #define kparam_block_sysfs_write(name) \
248 do { \
249 BUG_ON(!(__param_##name.perm & 0222)); \
250 __kernel_param_lock(); \
251 } while (0)
252
253 /**
254 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
255 * @name: the name of the parameter
256 */
257 #define kparam_unblock_sysfs_write(name) \
258 do { \
259 BUG_ON(!(__param_##name.perm & 0222)); \
260 __kernel_param_unlock(); \
261 } while (0)
262
263 /**
264 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
265 * @name: the name of the parameter
266 *
267 * This also blocks sysfs writes.
268 */
269 #define kparam_block_sysfs_read(name) \
270 do { \
271 BUG_ON(!(__param_##name.perm & 0444)); \
272 __kernel_param_lock(); \
273 } while (0)
274
275 /**
276 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
277 * @name: the name of the parameter
278 */
279 #define kparam_unblock_sysfs_read(name) \
280 do { \
281 BUG_ON(!(__param_##name.perm & 0444)); \
282 __kernel_param_unlock(); \
283 } while (0)
284
285 #ifdef CONFIG_SYSFS
286 extern void __kernel_param_lock(void);
287 extern void __kernel_param_unlock(void);
288 #else
289 static inline void __kernel_param_lock(void)
290 {
291 }
292 static inline void __kernel_param_unlock(void)
293 {
294 }
295 #endif
296
297 #ifndef MODULE
298 /**
299 * core_param - define a historical core kernel parameter.
300 * @name: the name of the cmdline and sysfs parameter (often the same as var)
301 * @var: the variable
302 * @type: the type of the parameter
303 * @perm: visibility in sysfs
304 *
305 * core_param is just like module_param(), but cannot be modular and
306 * doesn't add a prefix (such as "printk."). This is for compatibility
307 * with __setup(), and it makes sense as truly core parameters aren't
308 * tied to the particular file they're in.
309 */
310 #define core_param(name, var, type, perm) \
311 param_check_##type(name, &(var)); \
312 __module_param_call("", name, &param_ops_##type, &var, perm, -1, 0)
313 #endif /* !MODULE */
314
315 /**
316 * module_param_string - a char array parameter
317 * @name: the name of the parameter
318 * @string: the string variable
319 * @len: the maximum length of the string, incl. terminator
320 * @perm: visibility in sysfs.
321 *
322 * This actually copies the string when it's set (unlike type charp).
323 * @len is usually just sizeof(string).
324 */
325 #define module_param_string(name, string, len, perm) \
326 static const struct kparam_string __param_string_##name \
327 = { len, string }; \
328 __module_param_call(MODULE_PARAM_PREFIX, name, \
329 &param_ops_string, \
330 .str = &__param_string_##name, perm, -1, 0);\
331 __MODULE_PARM_TYPE(name, "string")
332
333 /**
334 * parameq - checks if two parameter names match
335 * @name1: parameter name 1
336 * @name2: parameter name 2
337 *
338 * Returns true if the two parameter names are equal.
339 * Dashes (-) are considered equal to underscores (_).
340 */
341 extern bool parameq(const char *name1, const char *name2);
342
343 /**
344 * parameqn - checks if two parameter names match
345 * @name1: parameter name 1
346 * @name2: parameter name 2
347 * @n: the length to compare
348 *
349 * Similar to parameq(), except it compares @n characters.
350 */
351 extern bool parameqn(const char *name1, const char *name2, size_t n);
352
353 /* Called on module insert or kernel boot */
354 extern char *parse_args(const char *name,
355 char *args,
356 const struct kernel_param *params,
357 unsigned num,
358 s16 level_min,
359 s16 level_max,
360 int (*unknown)(char *param, char *val,
361 const char *doing));
362
363 /* Called by module remove. */
364 #ifdef CONFIG_SYSFS
365 extern void destroy_params(const struct kernel_param *params, unsigned num);
366 #else
367 static inline void destroy_params(const struct kernel_param *params,
368 unsigned num)
369 {
370 }
371 #endif /* !CONFIG_SYSFS */
372
373 /* All the helper functions */
374 /* The macros to do compile-time type checking stolen from Jakub
375 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
376 #define __param_check(name, p, type) \
377 static inline type __always_unused *__check_##name(void) { return(p); }
378
379 extern struct kernel_param_ops param_ops_byte;
380 extern int param_set_byte(const char *val, const struct kernel_param *kp);
381 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
382 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
383
384 extern struct kernel_param_ops param_ops_short;
385 extern int param_set_short(const char *val, const struct kernel_param *kp);
386 extern int param_get_short(char *buffer, const struct kernel_param *kp);
387 #define param_check_short(name, p) __param_check(name, p, short)
388
389 extern struct kernel_param_ops param_ops_ushort;
390 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
391 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
392 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
393
394 extern struct kernel_param_ops param_ops_int;
395 extern int param_set_int(const char *val, const struct kernel_param *kp);
396 extern int param_get_int(char *buffer, const struct kernel_param *kp);
397 #define param_check_int(name, p) __param_check(name, p, int)
398
399 extern struct kernel_param_ops param_ops_uint;
400 extern int param_set_uint(const char *val, const struct kernel_param *kp);
401 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
402 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
403
404 extern struct kernel_param_ops param_ops_long;
405 extern int param_set_long(const char *val, const struct kernel_param *kp);
406 extern int param_get_long(char *buffer, const struct kernel_param *kp);
407 #define param_check_long(name, p) __param_check(name, p, long)
408
409 extern struct kernel_param_ops param_ops_ulong;
410 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
411 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
412 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
413
414 extern struct kernel_param_ops param_ops_ullong;
415 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
416 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
417 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
418
419 extern struct kernel_param_ops param_ops_charp;
420 extern int param_set_charp(const char *val, const struct kernel_param *kp);
421 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
422 #define param_check_charp(name, p) __param_check(name, p, char *)
423
424 /* We used to allow int as well as bool. We're taking that away! */
425 extern struct kernel_param_ops param_ops_bool;
426 extern int param_set_bool(const char *val, const struct kernel_param *kp);
427 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
428 #define param_check_bool(name, p) __param_check(name, p, bool)
429
430 extern struct kernel_param_ops param_ops_invbool;
431 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
432 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
433 #define param_check_invbool(name, p) __param_check(name, p, bool)
434
435 /* An int, which can only be set like a bool (though it shows as an int). */
436 extern struct kernel_param_ops param_ops_bint;
437 extern int param_set_bint(const char *val, const struct kernel_param *kp);
438 #define param_get_bint param_get_int
439 #define param_check_bint param_check_int
440
441 /**
442 * module_param_array - a parameter which is an array of some type
443 * @name: the name of the array variable
444 * @type: the type, as per module_param()
445 * @nump: optional pointer filled in with the number written
446 * @perm: visibility in sysfs
447 *
448 * Input and output are as comma-separated values. Commas inside values
449 * don't work properly (eg. an array of charp).
450 *
451 * ARRAY_SIZE(@name) is used to determine the number of elements in the
452 * array, so the definition must be visible.
453 */
454 #define module_param_array(name, type, nump, perm) \
455 module_param_array_named(name, name, type, nump, perm)
456
457 /**
458 * module_param_array_named - renamed parameter which is an array of some type
459 * @name: a valid C identifier which is the parameter name
460 * @array: the name of the array variable
461 * @type: the type, as per module_param()
462 * @nump: optional pointer filled in with the number written
463 * @perm: visibility in sysfs
464 *
465 * This exposes a different name than the actual variable name. See
466 * module_param_named() for why this might be necessary.
467 */
468 #define module_param_array_named(name, array, type, nump, perm) \
469 param_check_##type(name, &(array)[0]); \
470 static const struct kparam_array __param_arr_##name \
471 = { .max = ARRAY_SIZE(array), .num = nump, \
472 .ops = &param_ops_##type, \
473 .elemsize = sizeof(array[0]), .elem = array }; \
474 __module_param_call(MODULE_PARAM_PREFIX, name, \
475 &param_array_ops, \
476 .arr = &__param_arr_##name, \
477 perm, -1, 0); \
478 __MODULE_PARM_TYPE(name, "array of " #type)
479
480 extern struct kernel_param_ops param_array_ops;
481
482 extern struct kernel_param_ops param_ops_string;
483 extern int param_set_copystring(const char *val, const struct kernel_param *);
484 extern int param_get_string(char *buffer, const struct kernel_param *kp);
485
486 /* for exporting parameters in /sys/module/.../parameters */
487
488 struct module;
489
490 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
491 extern int module_param_sysfs_setup(struct module *mod,
492 const struct kernel_param *kparam,
493 unsigned int num_params);
494
495 extern void module_param_sysfs_remove(struct module *mod);
496 #else
497 static inline int module_param_sysfs_setup(struct module *mod,
498 const struct kernel_param *kparam,
499 unsigned int num_params)
500 {
501 return 0;
502 }
503
504 static inline void module_param_sysfs_remove(struct module *mod)
505 { }
506 #endif
507
508 #endif /* _LINUX_MODULE_PARAMS_H */