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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#define ___module_cat(a,b) __mod_ ## a ## b
20#define __module_cat(a,b) ___module_cat(a,b)
21#ifdef MODULE
22#define __MODULE_INFO(tag, name, info) \
23static const char __module_cat(name,__LINE__)[] \
24 __used __attribute__((section(".modinfo"), unused, aligned(1))) \
25 = __stringify(tag) "=" info
26#else /* !MODULE */
27/* This struct is here for syntactic coherency, it is not used */
28#define __MODULE_INFO(tag, name, info) \
29 struct __module_cat(name,__LINE__) {}
30#endif
31#define __MODULE_PARM_TYPE(name, _type) \
32 __MODULE_INFO(parmtype, name##type, #name ":" _type)
33
34/* One for each parameter, describing how to use it. Some files do
35 multiple of these per line, so can't just use MODULE_INFO. */
36#define MODULE_PARM_DESC(_parm, desc) \
37 __MODULE_INFO(parm, _parm, #_parm ":" desc)
38
39struct kernel_param;
40
41struct kernel_param_ops {
42 /* Returns 0, or -errno. arg is in kp->arg. */
43 int (*set)(const char *val, const struct kernel_param *kp);
44 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
45 int (*get)(char *buffer, const struct kernel_param *kp);
46 /* Optional function to free kp->arg when module unloaded. */
47 void (*free)(void *arg);
48};
49
50/* Flag bits for kernel_param.flags */
51#define KPARAM_ISBOOL 2
52
53struct kernel_param {
54 const char *name;
55 const struct kernel_param_ops *ops;
56 u16 perm;
57 u16 flags;
58 union {
59 void *arg;
60 const struct kparam_string *str;
61 const struct kparam_array *arr;
62 };
63};
64
65/* Special one for strings we want to copy into */
66struct kparam_string {
67 unsigned int maxlen;
68 char *string;
69};
70
71/* Special one for arrays */
72struct kparam_array
73{
74 unsigned int max;
75 unsigned int elemsize;
76 unsigned int *num;
77 const struct kernel_param_ops *ops;
78 void *elem;
79};
80
81/**
82 * module_param - typesafe helper for a module/cmdline parameter
83 * @value: the variable to alter, and exposed parameter name.
84 * @type: the type of the parameter
85 * @perm: visibility in sysfs.
86 *
87 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
88 * ".") the kernel commandline parameter. Note that - is changed to _, so
89 * the user can use "foo-bar=1" even for variable "foo_bar".
90 *
91 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
92 * for world-readable, 0644 for root-writable, etc. Note that if it
93 * is writable, you may need to use kparam_block_sysfs_write() around
94 * accesses (esp. charp, which can be kfreed when it changes).
95 *
96 * The @type is simply pasted to refer to a param_ops_##type and a
97 * param_check_##type: for convenience many standard types are provided but
98 * you can create your own by defining those variables.
99 *
100 * Standard types are:
101 * byte, short, ushort, int, uint, long, ulong
102 * charp: a character pointer
103 * bool: a bool, values 0/1, y/n, Y/N.
104 * invbool: the above, only sense-reversed (N = true).
105 */
106#define module_param(name, type, perm) \
107 module_param_named(name, name, type, perm)
108
109/**
110 * module_param_named - typesafe helper for a renamed module/cmdline parameter
111 * @name: a valid C identifier which is the parameter name.
112 * @value: the actual lvalue to alter.
113 * @type: the type of the parameter
114 * @perm: visibility in sysfs.
115 *
116 * Usually it's a good idea to have variable names and user-exposed names the
117 * same, but that's harder if the variable must be non-static or is inside a
118 * structure. This allows exposure under a different name.
119 */
120#define module_param_named(name, value, type, perm) \
121 param_check_##type(name, &(value)); \
122 module_param_cb(name, ¶m_ops_##type, &value, perm); \
123 __MODULE_PARM_TYPE(name, #type)
124
125/**
126 * module_param_cb - general callback for a module/cmdline parameter
127 * @name: a valid C identifier which is the parameter name.
128 * @ops: the set & get operations for this parameter.
129 * @perm: visibility in sysfs.
130 *
131 * The ops can have NULL set or get functions.
132 */
133#define module_param_cb(name, ops, arg, perm) \
134 __module_param_call(MODULE_PARAM_PREFIX, \
135 name, ops, arg, __same_type((arg), bool *), perm)
136
137/* On alpha, ia64 and ppc64 relocations to global data cannot go into
138 read-only sections (which is part of respective UNIX ABI on these
139 platforms). So 'const' makes no sense and even causes compile failures
140 with some compilers. */
141#if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
142#define __moduleparam_const
143#else
144#define __moduleparam_const const
145#endif
146
147/* This is the fundamental function for registering boot/module
148 parameters. */
149#define __module_param_call(prefix, name, ops, arg, isbool, perm) \
150 /* Default value instead of permissions? */ \
151 static int __param_perm_check_##name __attribute__((unused)) = \
152 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
153 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
154 static const char __param_str_##name[] = prefix #name; \
155 static struct kernel_param __moduleparam_const __param_##name \
156 __used \
157 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
158 = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \
159 { arg } }
160
161/* Obsolete - use module_param_cb() */
162#define module_param_call(name, set, get, arg, perm) \
163 static struct kernel_param_ops __param_ops_##name = \
164 { (void *)set, (void *)get }; \
165 __module_param_call(MODULE_PARAM_PREFIX, \
166 name, &__param_ops_##name, arg, \
167 __same_type(arg, bool *), \
168 (perm) + sizeof(__check_old_set_param(set))*0)
169
170/* We don't get oldget: it's often a new-style param_get_uint, etc. */
171static inline int
172__check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
173{
174 return 0;
175}
176
177/**
178 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
179 * @name: the name of the parameter
180 *
181 * There's no point blocking write on a paramter that isn't writable via sysfs!
182 */
183#define kparam_block_sysfs_write(name) \
184 do { \
185 BUG_ON(!(__param_##name.perm & 0222)); \
186 __kernel_param_lock(); \
187 } while (0)
188
189/**
190 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
191 * @name: the name of the parameter
192 */
193#define kparam_unblock_sysfs_write(name) \
194 do { \
195 BUG_ON(!(__param_##name.perm & 0222)); \
196 __kernel_param_unlock(); \
197 } while (0)
198
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/**
212 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
213 * @name: the name of the parameter
214 */
215#define kparam_unblock_sysfs_read(name) \
216 do { \
217 BUG_ON(!(__param_##name.perm & 0444)); \
218 __kernel_param_unlock(); \
219 } while (0)
220
221#ifdef CONFIG_SYSFS
222extern void __kernel_param_lock(void);
223extern void __kernel_param_unlock(void);
224#else
225static inline void __kernel_param_lock(void)
226{
227}
228static inline void __kernel_param_unlock(void)
229{
230}
231#endif
232
233#ifndef MODULE
234/**
235 * core_param - define a historical core kernel parameter.
236 * @name: the name of the cmdline and sysfs parameter (often the same as var)
237 * @var: the variable
238 * @type: the type of the parameter
239 * @perm: visibility in sysfs
240 *
241 * core_param is just like module_param(), but cannot be modular and
242 * doesn't add a prefix (such as "printk."). This is for compatibility
243 * with __setup(), and it makes sense as truly core parameters aren't
244 * tied to the particular file they're in.
245 */
246#define core_param(name, var, type, perm) \
247 param_check_##type(name, &(var)); \
248 __module_param_call("", name, ¶m_ops_##type, \
249 &var, __same_type(var, bool), perm)
250#endif /* !MODULE */
251
252/**
253 * module_param_string - a char array parameter
254 * @name: the name of the parameter
255 * @string: the string variable
256 * @len: the maximum length of the string, incl. terminator
257 * @perm: visibility in sysfs.
258 *
259 * This actually copies the string when it's set (unlike type charp).
260 * @len is usually just sizeof(string).
261 */
262#define module_param_string(name, string, len, perm) \
263 static const struct kparam_string __param_string_##name \
264 = { len, string }; \
265 __module_param_call(MODULE_PARAM_PREFIX, name, \
266 ¶m_ops_string, \
267 .str = &__param_string_##name, 0, perm); \
268 __MODULE_PARM_TYPE(name, "string")
269
270/**
271 * parameq - checks if two parameter names match
272 * @name1: parameter name 1
273 * @name2: parameter name 2
274 *
275 * Returns true if the two parameter names are equal.
276 * Dashes (-) are considered equal to underscores (_).
277 */
278extern bool parameq(const char *name1, const char *name2);
279
280/**
281 * parameqn - checks if two parameter names match
282 * @name1: parameter name 1
283 * @name2: parameter name 2
284 * @n: the length to compare
285 *
286 * Similar to parameq(), except it compares @n characters.
287 */
288extern bool parameqn(const char *name1, const char *name2, size_t n);
289
290/* Called on module insert or kernel boot */
291extern int parse_args(const char *name,
292 char *args,
293 const struct kernel_param *params,
294 unsigned num,
295 int (*unknown)(char *param, char *val));
296
297/* Called by module remove. */
298#ifdef CONFIG_SYSFS
299extern void destroy_params(const struct kernel_param *params, unsigned num);
300#else
301static inline void destroy_params(const struct kernel_param *params,
302 unsigned num)
303{
304}
305#endif /* !CONFIG_SYSFS */
306
307/* All the helper functions */
308/* The macros to do compile-time type checking stolen from Jakub
309 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
310#define __param_check(name, p, type) \
311 static inline type *__check_##name(void) { return(p); }
312
313extern struct kernel_param_ops param_ops_byte;
314extern int param_set_byte(const char *val, const struct kernel_param *kp);
315extern int param_get_byte(char *buffer, const struct kernel_param *kp);
316#define param_check_byte(name, p) __param_check(name, p, unsigned char)
317
318extern struct kernel_param_ops param_ops_short;
319extern int param_set_short(const char *val, const struct kernel_param *kp);
320extern int param_get_short(char *buffer, const struct kernel_param *kp);
321#define param_check_short(name, p) __param_check(name, p, short)
322
323extern struct kernel_param_ops param_ops_ushort;
324extern int param_set_ushort(const char *val, const struct kernel_param *kp);
325extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
326#define param_check_ushort(name, p) __param_check(name, p, unsigned short)
327
328extern struct kernel_param_ops param_ops_int;
329extern int param_set_int(const char *val, const struct kernel_param *kp);
330extern int param_get_int(char *buffer, const struct kernel_param *kp);
331#define param_check_int(name, p) __param_check(name, p, int)
332
333extern struct kernel_param_ops param_ops_uint;
334extern int param_set_uint(const char *val, const struct kernel_param *kp);
335extern int param_get_uint(char *buffer, const struct kernel_param *kp);
336#define param_check_uint(name, p) __param_check(name, p, unsigned int)
337
338extern struct kernel_param_ops param_ops_long;
339extern int param_set_long(const char *val, const struct kernel_param *kp);
340extern int param_get_long(char *buffer, const struct kernel_param *kp);
341#define param_check_long(name, p) __param_check(name, p, long)
342
343extern struct kernel_param_ops param_ops_ulong;
344extern int param_set_ulong(const char *val, const struct kernel_param *kp);
345extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
346#define param_check_ulong(name, p) __param_check(name, p, unsigned long)
347
348extern struct kernel_param_ops param_ops_charp;
349extern int param_set_charp(const char *val, const struct kernel_param *kp);
350extern int param_get_charp(char *buffer, const struct kernel_param *kp);
351#define param_check_charp(name, p) __param_check(name, p, char *)
352
353/* We used to allow int as well as bool. We're taking that away! */
354extern struct kernel_param_ops param_ops_bool;
355extern int param_set_bool(const char *val, const struct kernel_param *kp);
356extern int param_get_bool(char *buffer, const struct kernel_param *kp);
357#define param_check_bool(name, p) __param_check(name, p, bool)
358
359extern struct kernel_param_ops param_ops_invbool;
360extern int param_set_invbool(const char *val, const struct kernel_param *kp);
361extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
362#define param_check_invbool(name, p) __param_check(name, p, bool)
363
364/* An int, which can only be set like a bool (though it shows as an int). */
365extern struct kernel_param_ops param_ops_bint;
366extern int param_set_bint(const char *val, const struct kernel_param *kp);
367#define param_get_bint param_get_int
368#define param_check_bint param_check_int
369
370/**
371 * module_param_array - a parameter which is an array of some type
372 * @name: the name of the array variable
373 * @type: the type, as per module_param()
374 * @nump: optional pointer filled in with the number written
375 * @perm: visibility in sysfs
376 *
377 * Input and output are as comma-separated values. Commas inside values
378 * don't work properly (eg. an array of charp).
379 *
380 * ARRAY_SIZE(@name) is used to determine the number of elements in the
381 * array, so the definition must be visible.
382 */
383#define module_param_array(name, type, nump, perm) \
384 module_param_array_named(name, name, type, nump, perm)
385
386/**
387 * module_param_array_named - renamed parameter which is an array of some type
388 * @name: a valid C identifier which is the parameter name
389 * @array: the name of the array variable
390 * @type: the type, as per module_param()
391 * @nump: optional pointer filled in with the number written
392 * @perm: visibility in sysfs
393 *
394 * This exposes a different name than the actual variable name. See
395 * module_param_named() for why this might be necessary.
396 */
397#define module_param_array_named(name, array, type, nump, perm) \
398 param_check_##type(name, &(array)[0]); \
399 static const struct kparam_array __param_arr_##name \
400 = { .max = ARRAY_SIZE(array), .num = nump, \
401 .ops = ¶m_ops_##type, \
402 .elemsize = sizeof(array[0]), .elem = array }; \
403 __module_param_call(MODULE_PARAM_PREFIX, name, \
404 ¶m_array_ops, \
405 .arr = &__param_arr_##name, \
406 __same_type(array[0], bool), perm); \
407 __MODULE_PARM_TYPE(name, "array of " #type)
408
409extern struct kernel_param_ops param_array_ops;
410
411extern struct kernel_param_ops param_ops_string;
412extern int param_set_copystring(const char *val, const struct kernel_param *);
413extern int param_get_string(char *buffer, const struct kernel_param *kp);
414
415/* for exporting parameters in /sys/parameters */
416
417struct module;
418
419#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
420extern int module_param_sysfs_setup(struct module *mod,
421 const struct kernel_param *kparam,
422 unsigned int num_params);
423
424extern void module_param_sysfs_remove(struct module *mod);
425#else
426static inline int module_param_sysfs_setup(struct module *mod,
427 const struct kernel_param *kparam,
428 unsigned int num_params)
429{
430 return 0;
431}
432
433static inline void module_param_sysfs_remove(struct module *mod)
434{ }
435#endif
436
437#endif /* _LINUX_MODULE_PARAMS_H */