cregit-Linux how code gets into the kernel

Release 4.7 include/linux/moduleparam.h

Directory: include/linux
#ifndef _LINUX_MODULE_PARAMS_H

#define _LINUX_MODULE_PARAMS_H
/* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
#include <linux/init.h>
#include <linux/stringify.h>
#include <linux/kernel.h>

/* You can override this manually, but generally this should match the
   module name. */
#ifdef MODULE

#define MODULE_PARAM_PREFIX 
/* empty */
#else

#define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
#endif

/* Chosen so that structs with an unsigned long line up. */

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

#ifdef MODULE

#define __MODULE_INFO(tag, name, info)					  \
static const char __UNIQUE_ID(name)[]                                     \
  __used __attribute__((section(".modinfo"), unused, aligned(1)))         \
  = __stringify(tag) "=" info
#else  /* !MODULE */
/* This struct is here for syntactic coherency, it is not used */

#define __MODULE_INFO(tag, name, info)					  \
  struct __UNIQUE_ID(name) {}
#endif

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

/* One for each parameter, describing how to use it.  Some files do
   multiple of these per line, so can't just use MODULE_INFO. */

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

struct kernel_param;

/*
 * Flags available for kernel_param_ops
 *
 * NOARG - the parameter allows for no argument (foo instead of foo=1)
 */
enum {
	
KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
};


struct kernel_param_ops {
	/* How the ops should behave */
	
unsigned int flags;
	/* Returns 0, or -errno.  arg is in kp->arg. */
	
int (*set)(const char *val, const struct kernel_param *kp);
	/* Returns length written or -errno.  Buffer is 4k (ie. be short!) */
	
int (*get)(char *buffer, const struct kernel_param *kp);
	/* Optional function to free kp->arg when module unloaded. */
	
void (*free)(void *arg);
};

/*
 * Flags available for kernel_param
 *
 * UNSAFE - the parameter is dangerous and setting it will taint the kernel
 */
enum {
	
KERNEL_PARAM_FL_UNSAFE = (1 << 0)
};


struct kernel_param {
	
const char *name;
	
struct module *mod;
	
const struct kernel_param_ops *ops;
	
const u16 perm;
	
s8 level;
	
u8 flags;
	union {
		
void *arg;
		
const struct kparam_string *str;
		
const struct kparam_array *arr;
	};
};

extern const struct kernel_param __start___param[], __stop___param[];

/* Special one for strings we want to copy into */

struct kparam_string {
	
unsigned int maxlen;
	
char *string;
};

/* Special one for arrays */

struct kparam_array
{
	
unsigned int max;
	
unsigned int elemsize;
	
unsigned int *num;
	
const struct kernel_param_ops *ops;
	
void *elem;
};

/**
 * module_param - typesafe helper for a module/cmdline parameter
 * @value: the variable to alter, and exposed parameter name.
 * @type: the type of the parameter
 * @perm: visibility in sysfs.
 *
 * @value 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".
 *
 * @perm 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 kernel_param_lock() around
 * accesses (esp. charp, which can be kfreed when it changes).
 *
 * The @type 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).
 */

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

/**
 * module_param_unsafe - same as module_param but taints kernel
 */

#define module_param_unsafe(name, type, perm)			\
	module_param_named_unsafe(name, name, type, perm)

/**
 * module_param_named - typesafe helper for a renamed module/cmdline parameter
 * @name: a valid C identifier which is the parameter name.
 * @value: the actual lvalue to alter.
 * @type: the type of the parameter
 * @perm: visibility in sysfs.
 *
 * Usually it's a good idea to have variable names and user-exposed names the
 * same, but that's harder if the variable must be non-static or is inside a
 * structure.  This allows exposure under a different name.
 */

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

/**
 * module_param_named_unsafe - same as module_param_named but taints kernel
 */

#define module_param_named_unsafe(name, value, type, perm)		\
	param_check_##type(name, &(value));                             \
        module_param_cb_unsafe(name, &param_ops_##type, &value, perm);  \
        __MODULE_PARM_TYPE(name, #type)

/**
 * module_param_cb - general callback for a module/cmdline parameter
 * @name: a valid C identifier which is the parameter name.
 * @ops: the set & get operations for this parameter.
 * @perm: visibility in sysfs.
 *
 * The ops can have NULL set or get functions.
 */

#define module_param_cb(name, ops, arg, perm)				      \
	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)


#define module_param_cb_unsafe(name, ops, arg, perm)			      \
	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1,    \
                            KERNEL_PARAM_FL_UNSAFE)

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

#define __level_param_cb(name, ops, arg, perm, level)			\
	__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)


#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)

/* On alpha, ia64 and ppc64 relocations to global data cannot go into
   read-only sections (which is part of respective UNIX ABI on these
   platforms). So 'const' makes no sense and even causes compile failures
   with some compilers. */
#if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)

#define __moduleparam_const
#else

#define __moduleparam_const const
#endif

/* This is the fundamental function for registering boot/module
   parameters. */

#define __module_param_call(prefix, name, ops, arg, perm, level, flags)	\
	/* Default value instead of permissions? */			\
	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, THIS_MODULE, ops,                       \
            VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }

/* Obsolete - use module_param_cb() */

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

/* We don't get oldget: it's often a new-style param_get_uint, etc. */

static inline int __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) { return 0; }

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#ifdef CONFIG_SYSFS extern void kernel_param_lock(struct module *mod); extern void kernel_param_unlock(struct module *mod); #else
static inline void kernel_param_lock(struct module *mod) { }

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static inline void kernel_param_unlock(struct module *mod) { }

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#endif #ifndef MODULE /** * core_param - define a historical core kernel parameter. * @name: the name of the cmdline and sysfs parameter (often the same as var) * @var: the variable * @type: the type of the parameter * @perm: visibility in sysfs * * core_param is just like module_param(), but cannot be modular and * doesn't add a prefix (such as "printk."). This is for compatibility * with __setup(), and it makes sense as truly core parameters aren't * tied to the particular file they're in. */ #define core_param(name, var, type, perm) \ param_check_##type(name, &(var)); \ __module_param_call("", name, &param_ops_##type, &var, perm, -1, 0) /** * core_param_unsafe - same as core_param but taints kernel */ #define core_param_unsafe(name, var, type, perm) \ param_check_##type(name, &(var)); \ __module_param_call("", name, &param_ops_##type, &var, perm, \ -1, KERNEL_PARAM_FL_UNSAFE) #endif /* !MODULE */ /** * module_param_string - a char array parameter * @name: the name of the parameter * @string: the string variable * @len: the maximum length of the string, incl. terminator * @perm: visibility in sysfs. * * This actually copies the string when it's set (unlike type charp). * @len is usually just sizeof(string). */ #define module_param_string(name, string, len, perm) \ 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, 0);\ __MODULE_PARM_TYPE(name, "string") /** * parameq - checks if two parameter names match * @name1: parameter name 1 * @name2: parameter name 2 * * Returns true if the two parameter names are equal. * Dashes (-) are considered equal to underscores (_). */ extern bool parameq(const char *name1, const char *name2); /** * parameqn - checks if two parameter names match * @name1: parameter name 1 * @name2: parameter name 2 * @n: the length to compare * * Similar to parameq(), except it compares @n characters. */ extern bool parameqn(const char *name1, const char *name2, size_t n); /* Called on module insert or kernel boot */ extern char *parse_args(const char *name, char *args, const struct kernel_param *params, unsigned num, s16 level_min, s16 level_max, void *arg, int (*unknown)(char *param, char *val, const char *doing, void *arg)); /* Called by module remove. */ #ifdef CONFIG_SYSFS extern void destroy_params(const struct kernel_param *params, unsigned num); #else
static inline void destroy_params(const struct kernel_param *params, unsigned num) { }

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#endif /* !CONFIG_SYSFS */ /* All the helper functions */ /* The macros to do compile-time type checking stolen from Jakub Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ #define __param_check(name, p, type) \ static inline type __always_unused *__check_##name(void) { return(p); } extern const struct kernel_param_ops param_ops_byte; extern int param_set_byte(const char *val, const struct kernel_param *kp); extern int param_get_byte(char *buffer, const struct kernel_param *kp); #define param_check_byte(name, p) __param_check(name, p, unsigned char) extern const struct kernel_param_ops param_ops_short; extern int param_set_short(const char *val, const struct kernel_param *kp); extern int param_get_short(char *buffer, const struct kernel_param *kp); #define param_check_short(name, p) __param_check(name, p, short) extern const struct kernel_param_ops param_ops_ushort; extern int param_set_ushort(const char *val, const struct kernel_param *kp); extern int param_get_ushort(char *buffer, const struct kernel_param *kp); #define param_check_ushort(name, p) __param_check(name, p, unsigned short) extern const struct kernel_param_ops param_ops_int; extern int param_set_int(const char *val, const struct kernel_param *kp); extern int param_get_int(char *buffer, const struct kernel_param *kp); #define param_check_int(name, p) __param_check(name, p, int) extern const struct kernel_param_ops param_ops_uint; extern int param_set_uint(const char *val, const struct kernel_param *kp); extern int param_get_uint(char *buffer, const struct kernel_param *kp); #define param_check_uint(name, p) __param_check(name, p, unsigned int) extern const struct kernel_param_ops param_ops_long; extern int param_set_long(const char *val, const struct kernel_param *kp); extern int param_get_long(char *buffer, const struct kernel_param *kp); #define param_check_long(name, p) __param_check(name, p, long) extern const struct kernel_param_ops param_ops_ulong; extern int param_set_ulong(const char *val, const struct kernel_param *kp); extern int param_get_ulong(char *buffer, const struct kernel_param *kp); #define param_check_ulong(name, p) __param_check(name, p, unsigned long) extern const struct kernel_param_ops param_ops_ullong; extern int param_set_ullong(const char *val, const struct kernel_param *kp); extern int param_get_ullong(char *buffer, const struct kernel_param *kp); #define param_check_ullong(name, p) __param_check(name, p, unsigned long long) extern const struct kernel_param_ops param_ops_charp; extern int param_set_charp(const char *val, const struct kernel_param *kp); extern int param_get_charp(char *buffer, const struct kernel_param *kp); extern void param_free_charp(void *arg); #define param_check_charp(name, p) __param_check(name, p, char *) /* We used to allow int as well as bool. We're taking that away! */ extern const struct kernel_param_ops param_ops_bool; extern int param_set_bool(const char *val, const struct kernel_param *kp); extern int param_get_bool(char *buffer, const struct kernel_param *kp); #define param_check_bool(name, p) __param_check(name, p, bool) extern const struct kernel_param_ops param_ops_bool_enable_only; extern int param_set_bool_enable_only(const char *val, const struct kernel_param *kp); /* getter is the same as for the regular bool */ #define param_check_bool_enable_only param_check_bool extern const struct kernel_param_ops param_ops_invbool; extern int param_set_invbool(const char *val, const struct kernel_param *kp); extern int param_get_invbool(char *buffer, const struct kernel_param *kp); #define param_check_invbool(name, p) __param_check(name, p, bool) /* An int, which can only be set like a bool (though it shows as an int). */ extern const struct kernel_param_ops param_ops_bint; extern int param_set_bint(const char *val, const struct kernel_param *kp); #define param_get_bint param_get_int #define param_check_bint param_check_int /** * module_param_array - a parameter which is an array of some type * @name: the name of the array variable * @type: the type, as per module_param() * @nump: optional pointer filled in with the number written * @perm: visibility in sysfs * * Input and output are as comma-separated values. Commas inside values * don't work properly (eg. an array of charp). * * ARRAY_SIZE(@name) 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) /** * module_param_array_named - renamed parameter which is an array of some type * @name: a valid C identifier which is the parameter name * @array: the name of the array variable * @type: the type, as per module_param() * @nump: optional pointer filled in with the number written * @perm: 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) \ 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, 0); \ __MODULE_PARM_TYPE(name, "array of " #type) extern const struct kernel_param_ops param_array_ops; extern const struct kernel_param_ops param_ops_string; extern int param_set_copystring(const char *val, const struct kernel_param *); extern int param_get_string(char *buffer, const struct kernel_param *kp); /* for exporting parameters in /sys/module/.../parameters */ struct module; #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) extern int module_param_sysfs_setup(struct module *mod, const struct kernel_param *kparam, unsigned int num_params); extern void module_param_sysfs_remove(struct module *mod); #else
static inline int module_param_sysfs_setup(struct module *mod, const struct kernel_param *kparam, unsigned int num_params) { return 0; }

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static inline void module_param_sysfs_remove(struct module *mod) { }

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#endif #endif /* _LINUX_MODULE_PARAMS_H */

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Directory: include/linux
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