#include <linux/init.h>
#include <linux/stringify.h>
#include <linux/kernel.h>

Data Structures
struct	kernel_param_ops

struct	kernel_param

struct	kparam_string

struct	kparam_array

Macros
#define	MODULE_PARAM_PREFIX KBUILD_MODNAME "."

#define	MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))

#define	___module_cat(a, b) __mod_ ## a ## b

#define	__module_cat(a, b) ___module_cat(a,b)

#define	__MODULE_INFO(tag, name, info) struct __module_cat(name,__LINE__) {}

#define	__MODULE_PARM_TYPE(name, _type) __MODULE_INFO(parmtype, name##type, #name ":" _type)

#define	MODULE_PARM_DESC(_parm, desc) __MODULE_INFO(parm, _parm, #_parm ":" desc)

#define	module_param(name, type, perm) module_param_named(name, name, type, perm)

: the name of the cmdline and sysfs parameter (often the same as var)
core_param - define a historical core kernel parameter.
#define	core_param(name, var, type, perm)

) is used to determine the number of elements in the
array, so the definition must be visible.
#define	module_param_array(name, type, nump, perm) module_param_array_named(name, name, type, nump, perm)

Variables
struct kernel_param_ops	__attribute__

: a valid C identifier which is the parameter name.
<level>_param_cb - general callback for a module/cmdline parameter to be evaluated before certain initcall level : the set & get operations for this parameter. : visibility in sysfs. The ops can have NULL set or get functions.
#define	module_param_named(name, value, type, perm)

#define	module_param_cb(name, ops, arg, perm) __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1)

#define	__level_param_cb(name, ops, arg, perm, level) __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level)

#define	core_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 1)

#define	postcore_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 2)

#define	arch_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 3)

#define	subsys_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 4)

#define	fs_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 5)

#define	device_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 6)

#define	late_param_cb(name, ops, arg, perm) __level_param_cb(name, ops, arg, perm, 7)

#define	__moduleparam_const const

#define	__module_param_call(prefix, name, ops, arg, perm, level)

#define	module_param_call(name, set, get, arg, perm)

: the name of the parameter
module_param_string - a char array parameter : the string variable : the maximum length of the string, incl. terminator : visibility in sysfs. This actually copies the string when it's set (unlike type charp). is usually just sizeof(string).
#define	kparam_block_sysfs_write(name)

#define	kparam_unblock_sysfs_write(name)

#define	kparam_block_sysfs_read(name)

#define	kparam_unblock_sysfs_read(name)

#define	module_param_string(name, string, len, perm)

2: parameter name 2
: the length to compare Similar to parameq(), except it compares characters.
#define	__param_check(name, p, type) static inline type *__check_##name(void) { return(p); }

#define	param_check_byte(name, p) __param_check(name, p, unsigned char)

#define	param_check_short(name, p) __param_check(name, p, short)

#define	param_check_ushort(name, p) __param_check(name, p, unsigned short)

#define	param_check_int(name, p) __param_check(name, p, int)

#define	param_check_uint(name, p) __param_check(name, p, unsigned int)

#define	param_check_long(name, p) __param_check(name, p, long)

#define	param_check_ulong(name, p) __param_check(name, p, unsigned long)

#define	param_check_charp(name, p) __param_check(name, p, char *)

#define	param_check_bool(name, p) __param_check(name, p, bool)

#define	param_check_invbool(name, p) __param_check(name, p, bool)

#define	param_get_bint param_get_int

#define	param_check_bint param_check_int

struct kernel_param_ops	param_ops_byte

struct kernel_param_ops	param_ops_short

struct kernel_param_ops	param_ops_ushort

struct kernel_param_ops	param_ops_int

struct kernel_param_ops	param_ops_uint

struct kernel_param_ops	param_ops_long

struct kernel_param_ops	param_ops_ulong

struct kernel_param_ops	param_ops_charp

struct kernel_param_ops	param_ops_bool

struct kernel_param_ops	param_ops_invbool

struct kernel_param_ops	param_ops_bint

bool	parameq (const char name1, const char name2)

bool	parameqn (const char name1, const char name2, size_t n)

int	parse_args (const char name, char args, const struct kernel_param params, unsigned num, s16 level_min, s16 level_max, int(unknown)(char param, char val, const char *doing))

int	param_set_byte (const char val, const struct kernel_param kp)

int	param_get_byte (char buffer, const struct kernel_param kp)

int	param_set_short (const char val, const struct kernel_param kp)

int	param_get_short (char buffer, const struct kernel_param kp)

int	param_set_ushort (const char val, const struct kernel_param kp)

int	param_get_ushort (char buffer, const struct kernel_param kp)

int	param_set_int (const char val, const struct kernel_param kp)

int	param_get_int (char buffer, const struct kernel_param kp)

int	param_set_uint (const char val, const struct kernel_param kp)

int	param_get_uint (char buffer, const struct kernel_param kp)

int	param_set_long (const char val, const struct kernel_param kp)

int	param_get_long (char buffer, const struct kernel_param kp)

int	param_set_ulong (const char val, const struct kernel_param kp)

int	param_get_ulong (char buffer, const struct kernel_param kp)

int	param_set_charp (const char val, const struct kernel_param kp)

int	param_get_charp (char buffer, const struct kernel_param kp)

int	param_set_bool (const char val, const struct kernel_param kp)

int	param_get_bool (char buffer, const struct kernel_param kp)

int	param_set_invbool (const char val, const struct kernel_param kp)

int	param_get_invbool (char buffer, const struct kernel_param kp)

int	param_set_bint (const char val, const struct kernel_param kp)

: a valid C identifier which is the parameter name
module_param_array_named - renamed parameter which is an array of some type : the name of the array variable : the type, as per module_param() : optional pointer filled in with the number written : visibility in sysfs This exposes a different name than the actual variable name. See module_param_named() for why this might be necessary.
#define	module_param_array_named(name, array, type, nump, perm)

struct kernel_param_ops	param_array_ops

struct kernel_param_ops	param_ops_string

int	param_set_copystring (const char val, const struct kernel_param )

int	param_get_string (char buffer, const struct kernel_param kp)

Macro Definition Documentation

#define ___module_cat	(	a,
		b
	)	__mod_ ## a ## b

Definition at line 19 of file moduleparam.h.

#define __level_param_cb	(	name,
		ops,
		arg,
		perm,
		level
	)	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level)

Definition at line 142 of file moduleparam.h.

#define __module_cat	(	a,
		b
	)	___module_cat(a,b)

Definition at line 20 of file moduleparam.h.

#define __MODULE_INFO	(	tag,
		name,
		info
	)	struct __module_cat(name,__LINE__) {}

Definition at line 28 of file moduleparam.h.

#define __module_param_call	(	prefix,
		name,
		ops,
		arg,
		perm,
		level
	)

Value:

/* Default value instead of permissions? */         \
    static int __param_perm_check_##name __attribute__((unused)) =  \
    BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
    + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);   \
    static const char __param_str_##name[] = prefix #name;      \
    static struct kernel_param __moduleparam_const __param_##name   \
    __used                              \
    __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
    = { __param_str_##name, ops, perm, level, { arg } }

Definition at line 178 of file moduleparam.h.

#define __MODULE_PARM_TYPE	(	name,
		_type
	)	__MODULE_INFO(parmtype, name##type, #name ":" _type)

Definition at line 31 of file moduleparam.h.

#define __moduleparam_const const

Definition at line 173 of file moduleparam.h.

#define __param_check	(	name,
		p,
		type
	)	static inline type *__check_##name(void) { return(p); }

Definition at line 339 of file moduleparam.h.

#define arch_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 3)

Definition at line 151 of file moduleparam.h.

#define core_param	(	name,
		var,
		type,
		perm
	)

Value:

param_check_##type(name, &(var)); \

__module_param_call("", name, &param_ops_##type, &var, perm, -1)

Definition at line 273 of file moduleparam.h.

#define core_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 1)

Definition at line 145 of file moduleparam.h.

#define device_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 6)

Definition at line 160 of file moduleparam.h.

#define fs_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 5)

Definition at line 157 of file moduleparam.h.

#define kparam_block_sysfs_read ( name )

Value:

do {                        \
        BUG_ON(!(__param_##name.perm & 0444));  \
        __kernel_param_lock();          \
    } while (0)

Definition at line 232 of file moduleparam.h.

#define kparam_block_sysfs_write ( name )

Value:

do {                        \
        BUG_ON(!(__param_##name.perm & 0222));  \
        __kernel_param_lock();          \
    } while (0)

Definition at line 210 of file moduleparam.h.

#define kparam_unblock_sysfs_read ( name )

Value:

do {                        \
        BUG_ON(!(__param_##name.perm & 0444));  \
        __kernel_param_unlock();        \
    } while (0)

Definition at line 242 of file moduleparam.h.

#define kparam_unblock_sysfs_write ( name )

Value:

do {                        \
        BUG_ON(!(__param_##name.perm & 0222));  \
        __kernel_param_unlock();        \
    } while (0)

Definition at line 220 of file moduleparam.h.

#define late_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 7)

Definition at line 163 of file moduleparam.h.

#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))

Definition at line 17 of file moduleparam.h.

#define module_param	(	name,
		type,
		perm
	)	module_param_named(name, name, type, perm)

module_param - typesafe helper for a module/cmdline parameter : the variable to alter, and exposed parameter name. : the type of the parameter : visibility in sysfs.

becomes the module parameter, or (prefixed by KBUILD_MODNAME and a ".") the kernel commandline parameter. Note that - is changed to _, so the user can use "foo-bar=1" even for variable "foo_bar".

is 0 if the the variable is not to appear in sysfs, or 0444 for world-readable, 0644 for root-writable, etc. Note that if it is writable, you may need to use kparam_block_sysfs_write() around accesses (esp. charp, which can be kfreed when it changes).

The is simply pasted to refer to a param_ops_#type and a param_check_#type: for convenience many standard types are provided but you can create your own by defining those variables.

Standard types are: byte, short, ushort, int, uint, long, ulong charp: a character pointer bool: a bool, values 0/1, y/n, Y/N. invbool: the above, only sense-reversed (N = true).

Definition at line 103 of file moduleparam.h.

#define module_param_array	(	name,
		type,
		nump,
		perm
	)	module_param_array_named(name, name, type, nump, perm)

Definition at line 412 of file moduleparam.h.

#define module_param_array_named	(	name,
		array,
		type,
		nump,
		perm
	)

Value:

param_check_##type(name, &(array)[0]);              \
    static const struct kparam_array __param_arr_##name     \
    = { .max = ARRAY_SIZE(array), .num = nump,                      \
        .ops = &param_ops_##type,                   \
        .elemsize = sizeof(array[0]), .elem = array };      \
    __module_param_call(MODULE_PARAM_PREFIX, name,          \
                &param_array_ops,               \
                .arr = &__param_arr_##name,         \
                perm, -1);                  \
    __MODULE_PARM_TYPE(name, "array of " #type)

Definition at line 426 of file moduleparam.h.

#define module_param_call	(	name,
		set,
		get,
		arg,
		perm
	)

Value:

static struct kernel_param_ops __param_ops_##name =     \
         { (void *)set, (void *)get };              \
    __module_param_call(MODULE_PARAM_PREFIX,            \
                name, &__param_ops_##name, arg,     \
                (perm) + sizeof(__check_old_set_param(set))*0, -1)

Definition at line 190 of file moduleparam.h.

#define module_param_cb	(	name,
		ops,
		arg,
		perm
	)	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1)

Definition at line 130 of file moduleparam.h.

#define module_param_named	(	name,
		value,
		type,
		perm
	)

Value:

param_check_##type(name, &(value));                \
    module_param_cb(name, &param_ops_##type, &value, perm);        \
    __MODULE_PARM_TYPE(name, #type)

Definition at line 117 of file moduleparam.h.

#define MODULE_PARAM_PREFIX KBUILD_MODNAME "."

Definition at line 13 of file moduleparam.h.

#define module_param_string	(	name,
		string,
		len,
		perm
	)

Value:

static const struct kparam_string __param_string_##name     \
        = { len, string };                  \
    __module_param_call(MODULE_PARAM_PREFIX, name,          \
                &param_ops_string,              \
                .str = &__param_string_##name, perm, -1);   \
    __MODULE_PARM_TYPE(name, "string")

Definition at line 288 of file moduleparam.h.

#define MODULE_PARM_DESC	(	_parm,
		desc
	)	__MODULE_INFO(parm, _parm, #_parm ":" desc)

Definition at line 36 of file moduleparam.h.

#define param_check_bint param_check_int

Definition at line 397 of file moduleparam.h.

#define param_check_bool	(	name,
		p
	)	__param_check(name, p, bool)

Definition at line 386 of file moduleparam.h.

#define param_check_byte	(	name,
		p
	)	__param_check(name, p, unsigned char)

Definition at line 345 of file moduleparam.h.

#define param_check_charp	(	name,
		p
	)	__param_check(name, p, char *)

Definition at line 380 of file moduleparam.h.

#define param_check_int	(	name,
		p
	)	__param_check(name, p, int)

Definition at line 360 of file moduleparam.h.

#define param_check_invbool	(	name,
		p
	)	__param_check(name, p, bool)

Definition at line 391 of file moduleparam.h.

#define param_check_long	(	name,
		p
	)	__param_check(name, p, long)

Definition at line 370 of file moduleparam.h.

#define param_check_short	(	name,
		p
	)	__param_check(name, p, short)

Definition at line 350 of file moduleparam.h.

#define param_check_uint	(	name,
		p
	)	__param_check(name, p, unsigned int)

Definition at line 365 of file moduleparam.h.

#define param_check_ulong	(	name,
		p
	)	__param_check(name, p, unsigned long)

Definition at line 375 of file moduleparam.h.

#define param_check_ushort	(	name,
		p
	)	__param_check(name, p, unsigned short)

Definition at line 355 of file moduleparam.h.

#define param_get_bint param_get_int

Definition at line 396 of file moduleparam.h.

#define postcore_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 2)

Definition at line 148 of file moduleparam.h.

#define subsys_param_cb	(	name,
		ops,
		arg,
		perm
	)	__level_param_cb(name, ops, arg, perm, 4)

Definition at line 154 of file moduleparam.h.

Function Documentation

int param_get_bool	(	char *	buffer,
		const struct kernel_param *	kp
	)

Definition at line 315 of file params.c.

int param_get_byte	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_get_charp	(	char *	buffer,
		const struct kernel_param *	kp
	)

Definition at line 286 of file params.c.

int param_get_int	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_get_invbool	(	char *	buffer,
		const struct kernel_param *	kp
	)

Definition at line 343 of file params.c.

int param_get_long	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_get_short	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_get_string	(	char *	buffer,
		const struct kernel_param *	kp
	)

Definition at line 489 of file params.c.

int param_get_uint	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_get_ulong	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_get_ushort	(	char *	buffer,
		const struct kernel_param *	kp
	)

int param_set_bint	(	const char *	val,
		const struct kernel_param *	kp
	)

Definition at line 355 of file params.c.

int param_set_bool	(	const char *	val,
		const struct kernel_param *	kp
	)

Definition at line 305 of file params.c.

int param_set_byte	(	const char *	val,
		const struct kernel_param *	kp
	)

int param_set_charp	(	const char *	val,
		const struct kernel_param *	kp
	)

Definition at line 263 of file params.c.

int param_set_copystring	(	const char *	val,
		const struct kernel_param *
	)

Definition at line 475 of file params.c.

int param_set_int	(	const char *	val,
		const struct kernel_param *	kp
	)

int param_set_invbool	(	const char *	val,
		const struct kernel_param *	kp
	)

Definition at line 329 of file params.c.

int param_set_long	(	const char *	val,
		const struct kernel_param *	kp
	)

int param_set_short	(	const char *	val,
		const struct kernel_param *	kp
	)

int param_set_uint	(	const char *	val,
		const struct kernel_param *	kp
	)

int param_set_ulong	(	const char *	val,
		const struct kernel_param *	kp
	)

int param_set_ushort	(	const char *	val,
		const struct kernel_param *	kp
	)

bool parameq	(	const char *	name1,
		const char *	name2
	)

Definition at line 81 of file params.c.

bool parameqn	(	const char *	name1,
		const char *	name2,
		size_t	n
	)

Definition at line 70 of file params.c.

int parse_args	(	const char *	name,
		char *	args,
		const struct kernel_param *	params,
		unsigned	num,
		s16	level_min,
		s16	level_max,
		int()(char param, char val, const char doing)	unknown
	)