text: #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, .set = _set, .get = _get };		\
  	__module_param_call(MODULE_PARAM_PREFIX,			\
  			    name, &__param_ops_##name, arg, perm, -1, 0)
  
  #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)
  {
  }
  static inline void kernel_param_unlock(struct module *mod)
  {
  }
  #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)
  {
  }
  #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;
  }
  
  static inline void module_param_sysfs_remove(struct module *mod)
  { }
  #endif
  
  #endif /* _LINUX_MODULE_PARAMS_H */
  