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)					  \
21static 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
37struct 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 */
44enum {
45	KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
46};
47
48struct 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 */
64enum {
65	KERNEL_PARAM_FL_UNSAFE = (1 << 0)
66};
67
68struct 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
81extern const struct kernel_param __start___param[], __stop___param[];
82
83/* Special one for strings we want to copy into */
84struct kparam_string {
85	unsigned int maxlen;
86	char *string;
87};
88
89/* Special one for arrays */
90struct 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. */
235static 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
286extern void __kernel_param_lock(void);
287extern void __kernel_param_unlock(void);
288#else
289static inline void __kernel_param_lock(void)
290{
291}
292static 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 */
341extern 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 */
351extern bool parameqn(const char *name1, const char *name2, size_t n);
352
353/* Called on module insert or kernel boot */
354extern 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
365extern void destroy_params(const struct kernel_param *params, unsigned num);
366#else
367static 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
379extern struct kernel_param_ops param_ops_byte;
380extern int param_set_byte(const char *val, const struct kernel_param *kp);
381extern 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
384extern struct kernel_param_ops param_ops_short;
385extern int param_set_short(const char *val, const struct kernel_param *kp);
386extern int param_get_short(char *buffer, const struct kernel_param *kp);
387#define param_check_short(name, p) __param_check(name, p, short)
388
389extern struct kernel_param_ops param_ops_ushort;
390extern int param_set_ushort(const char *val, const struct kernel_param *kp);
391extern 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
394extern struct kernel_param_ops param_ops_int;
395extern int param_set_int(const char *val, const struct kernel_param *kp);
396extern int param_get_int(char *buffer, const struct kernel_param *kp);
397#define param_check_int(name, p) __param_check(name, p, int)
398
399extern struct kernel_param_ops param_ops_uint;
400extern int param_set_uint(const char *val, const struct kernel_param *kp);
401extern 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
404extern struct kernel_param_ops param_ops_long;
405extern int param_set_long(const char *val, const struct kernel_param *kp);
406extern int param_get_long(char *buffer, const struct kernel_param *kp);
407#define param_check_long(name, p) __param_check(name, p, long)
408
409extern struct kernel_param_ops param_ops_ulong;
410extern int param_set_ulong(const char *val, const struct kernel_param *kp);
411extern 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
414extern struct kernel_param_ops param_ops_ullong;
415extern int param_set_ullong(const char *val, const struct kernel_param *kp);
416extern 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
419extern struct kernel_param_ops param_ops_charp;
420extern int param_set_charp(const char *val, const struct kernel_param *kp);
421extern 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! */
425extern struct kernel_param_ops param_ops_bool;
426extern int param_set_bool(const char *val, const struct kernel_param *kp);
427extern int param_get_bool(char *buffer, const struct kernel_param *kp);
428#define param_check_bool(name, p) __param_check(name, p, bool)
429
430extern struct kernel_param_ops param_ops_invbool;
431extern int param_set_invbool(const char *val, const struct kernel_param *kp);
432extern 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). */
436extern struct kernel_param_ops param_ops_bint;
437extern 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
480extern struct kernel_param_ops param_array_ops;
481
482extern struct kernel_param_ops param_ops_string;
483extern int param_set_copystring(const char *val, const struct kernel_param *);
484extern int param_get_string(char *buffer, const struct kernel_param *kp);
485
486/* for exporting parameters in /sys/module/.../parameters */
487
488struct module;
489
490#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
491extern int module_param_sysfs_setup(struct module *mod,
492				    const struct kernel_param *kparam,
493				    unsigned int num_params);
494
495extern void module_param_sysfs_remove(struct module *mod);
496#else
497static 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
504static inline void module_param_sysfs_remove(struct module *mod)
505{ }
506#endif
507
508#endif /* _LINUX_MODULE_PARAMS_H */
509