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