/*
   * Copyright (C) 2004-2006 Atmel Corporation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #ifndef __ASM_AVR32_UACCESS_H
  #define __ASM_AVR32_UACCESS_H
  
  #include <linux/errno.h>
  #include <linux/sched.h>
  
  #define VERIFY_READ	0
  #define VERIFY_WRITE	1
  
  typedef struct {
  	unsigned int is_user_space;
  } mm_segment_t;
  
  /*
   * The fs value determines whether argument validity checking should be
   * performed or not.  If get_fs() == USER_DS, checking is performed, with
   * get_fs() == KERNEL_DS, checking is bypassed.
   *
   * For historical reasons (Data Segment Register?), these macros are misnamed.
   */
  #define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
  #define segment_eq(a, b)	((a).is_user_space == (b).is_user_space)
  
  #define USER_ADDR_LIMIT 0x80000000
  
  #define KERNEL_DS	MAKE_MM_SEG(0)
  #define USER_DS		MAKE_MM_SEG(1)
  
  #define get_ds()	(KERNEL_DS)
  
  static inline mm_segment_t get_fs(void)
  {
  	return MAKE_MM_SEG(test_thread_flag(TIF_USERSPACE));
  }
  
  static inline void set_fs(mm_segment_t s)
  {
  	if (s.is_user_space)
  		set_thread_flag(TIF_USERSPACE);
  	else
  		clear_thread_flag(TIF_USERSPACE);
  }
  
  /*
   * Test whether a block of memory is a valid user space address.
   * Returns 0 if the range is valid, nonzero otherwise.
   *
   * We do the following checks:
   *   1. Is the access from kernel space?
   *   2. Does (addr + size) set the carry bit?
   *   3. Is (addr + size) a negative number (i.e. >= 0x80000000)?
   *
   * If yes on the first check, access is granted.
   * If no on any of the others, access is denied.
   */
  #define __range_ok(addr, size)						\
  	(test_thread_flag(TIF_USERSPACE)				\
  	 && (((unsigned long)(addr) >= 0x80000000)			\
  	     || ((unsigned long)(size) > 0x80000000)			\
  	     || (((unsigned long)(addr) + (unsigned long)(size)) > 0x80000000)))
  
  #define access_ok(type, addr, size) (likely(__range_ok(addr, size) == 0))
  
  /* Generic arbitrary sized copy. Return the number of bytes NOT copied */
  extern __kernel_size_t __copy_user(void *to, const void *from,
  				   __kernel_size_t n);
  
  extern __kernel_size_t copy_to_user(void __user *to, const void *from,
  				    __kernel_size_t n);
  extern __kernel_size_t ___copy_from_user(void *to, const void __user *from,
  				      __kernel_size_t n);
  
  static inline __kernel_size_t __copy_to_user(void __user *to, const void *from,
  					     __kernel_size_t n)
  {
  	return __copy_user((void __force *)to, from, n);
  }
  static inline __kernel_size_t __copy_from_user(void *to,
  					       const void __user *from,
  					       __kernel_size_t n)
  {
  	return __copy_user(to, (const void __force *)from, n);
  }
  static inline __kernel_size_t copy_from_user(void *to,
  					       const void __user *from,
  					       __kernel_size_t n)
  {
  	size_t res = ___copy_from_user(to, from, n);
  	if (unlikely(res))
  		memset(to + (n - res), 0, res);
  	return res;
  }
  
  #define __copy_to_user_inatomic __copy_to_user
  #define __copy_from_user_inatomic __copy_from_user
  
  /*
   * put_user: - Write a simple value into user space.
   * @x:   Value to copy to user space.
   * @ptr: Destination address, in user space.
   *
   * Context: User context only. This function may sleep if pagefaults are
   *          enabled.
   *
   * This macro copies a single simple value from kernel space to user
   * space.  It supports simple types like char and int, but not larger
   * data types like structures or arrays.
   *
   * @ptr must have pointer-to-simple-variable type, and @x must be assignable
   * to the result of dereferencing @ptr.
   *
   * Returns zero on success, or -EFAULT on error.
   */
  #define put_user(x, ptr)	\
  	__put_user_check((x), (ptr), sizeof(*(ptr)))
  
  /*
   * get_user: - Get a simple variable from user space.
   * @x:   Variable to store result.
   * @ptr: Source address, in user space.
   *
   * Context: User context only. This function may sleep if pagefaults are
   *          enabled.
   *
   * This macro copies a single simple variable from user space to kernel
   * space.  It supports simple types like char and int, but not larger
   * data types like structures or arrays.
   *
   * @ptr must have pointer-to-simple-variable type, and the result of
   * dereferencing @ptr must be assignable to @x without a cast.
   *
   * Returns zero on success, or -EFAULT on error.
   * On error, the variable @x is set to zero.
   */
  #define get_user(x, ptr) \
  	__get_user_check((x), (ptr), sizeof(*(ptr)))
  
  /*
   * __put_user: - Write a simple value into user space, with less checking.
   * @x:   Value to copy to user space.
   * @ptr: Destination address, in user space.
   *
   * Context: User context only. This function may sleep if pagefaults are
   *          enabled.
   *
   * This macro copies a single simple value from kernel space to user
   * space.  It supports simple types like char and int, but not larger
   * data types like structures or arrays.
   *
   * @ptr must have pointer-to-simple-variable type, and @x must be assignable
   * to the result of dereferencing @ptr.
   *
   * Caller must check the pointer with access_ok() before calling this
   * function.
   *
   * Returns zero on success, or -EFAULT on error.
   */
  #define __put_user(x, ptr) \
  	__put_user_nocheck((x), (ptr), sizeof(*(ptr)))
  
  /*
   * __get_user: - Get a simple variable from user space, with less checking.
   * @x:   Variable to store result.
   * @ptr: Source address, in user space.
   *
   * Context: User context only. This function may sleep if pagefaults are
   *          enabled.
   *
   * This macro copies a single simple variable from user space to kernel
   * space.  It supports simple types like char and int, but not larger
   * data types like structures or arrays.
   *
   * @ptr must have pointer-to-simple-variable type, and the result of
   * dereferencing @ptr must be assignable to @x without a cast.
   *
   * Caller must check the pointer with access_ok() before calling this
   * function.
   *
   * Returns zero on success, or -EFAULT on error.
   * On error, the variable @x is set to zero.
   */
  #define __get_user(x, ptr) \
  	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  
  extern int __get_user_bad(void);
  extern int __put_user_bad(void);
  
  #define __get_user_nocheck(x, ptr, size)				\
  ({									\
  	unsigned long __gu_val = 0;					\
  	int __gu_err = 0;						\
  									\
  	switch (size) {							\
  	case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break;	\
  	case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break;	\
  	case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break;	\
  	default: __gu_err = __get_user_bad(); break;			\
  	}								\
  									\
  	x = (__force typeof(*(ptr)))__gu_val;				\
  	__gu_err;							\
  })
  
  #define __get_user_check(x, ptr, size)					\
  ({									\
  	unsigned long __gu_val = 0;					\
  	const typeof(*(ptr)) __user * __gu_addr = (ptr);		\
  	int __gu_err = 0;						\
  									\
  	if (access_ok(VERIFY_READ, __gu_addr, size)) {			\
  		switch (size) {						\
  		case 1:							\
  			__get_user_asm("ub", __gu_val, __gu_addr,	\
  				       __gu_err);			\
  			break;						\
  		case 2:							\
  			__get_user_asm("uh", __gu_val, __gu_addr,	\
  				       __gu_err);			\
  			break;						\
  		case 4:							\
  			__get_user_asm("w", __gu_val, __gu_addr,	\
  				       __gu_err);			\
  			break;						\
  		default:						\
  			__gu_err = __get_user_bad();			\
  			break;						\
  		}							\
  	} else {							\
  		__gu_err = -EFAULT;					\
  	}								\
  	x = (__force typeof(*(ptr)))__gu_val;				\
  	__gu_err;							\
  })
  
  #define __get_user_asm(suffix, __gu_val, ptr, __gu_err)			\
  	asm volatile(							\
  		"1:	ld." suffix "	%1, %3			
  "	\
  		"2:						
  "	\
  		"	.subsection 1				
  "	\
  		"3:	mov	%0, %4				
  "	\
  		"	rjmp	2b				
  "	\
  		"	.subsection 0				
  "	\
  		"	.section __ex_table, \"a\"		
  "	\
  		"	.long	1b, 3b				
  "	\
  		"	.previous				
  "	\
  		: "=r"(__gu_err), "=r"(__gu_val)			\
  		: "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
  
  #define __put_user_nocheck(x, ptr, size)				\
  ({									\
  	typeof(*(ptr)) __pu_val;					\
  	int __pu_err = 0;						\
  									\
  	__pu_val = (x);							\
  	switch (size) {							\
  	case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break;	\
  	case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break;	\
  	case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break;	\
  	case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break;	\
  	default: __pu_err = __put_user_bad(); break;			\
  	}								\
  	__pu_err;							\
  })
  
  #define __put_user_check(x, ptr, size)					\
  ({									\
  	typeof(*(ptr)) __pu_val;					\
  	typeof(*(ptr)) __user *__pu_addr = (ptr);			\
  	int __pu_err = 0;						\
  									\
  	__pu_val = (x);							\
  	if (access_ok(VERIFY_WRITE, __pu_addr, size)) {			\
  		switch (size) {						\
  		case 1:							\
  			__put_user_asm("b", __pu_addr, __pu_val,	\
  				       __pu_err);			\
  			break;						\
  		case 2:							\
  			__put_user_asm("h", __pu_addr, __pu_val,	\
  				       __pu_err);			\
  			break;						\
  		case 4:							\
  			__put_user_asm("w", __pu_addr, __pu_val,	\
  				       __pu_err);			\
  			break;						\
  		case 8:							\
  			__put_user_asm("d", __pu_addr, __pu_val,	\
  				       __pu_err);			\
  			break;						\
  		default:						\
  			__pu_err = __put_user_bad();			\
  			break;						\
  		}							\
  	} else {							\
  		__pu_err = -EFAULT;					\
  	}								\
  	__pu_err;							\
  })
  
  #define __put_user_asm(suffix, ptr, __pu_val, __gu_err)			\
  	asm volatile(							\
  		"1:	st." suffix "	%1, %3			
  "	\
  		"2:						
  "	\
  		"	.subsection 1				
  "	\
  		"3:	mov	%0, %4				
  "	\
  		"	rjmp	2b				
  "	\
  		"	.subsection 0				
  "	\
  		"	.section __ex_table, \"a\"		
  "	\
  		"	.long	1b, 3b				
  "	\
  		"	.previous				
  "	\
  		: "=r"(__gu_err), "=m"(*(ptr))				\
  		: "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
  
  extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
  extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
  
  extern long strncpy_from_user(char *dst, const char __user *src, long count);
  extern long __strncpy_from_user(char *dst, const char __user *src, long count);
  
  extern long strnlen_user(const char __user *__s, long __n);
  extern long __strnlen_user(const char __user *__s, long __n);
  
  #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
  
  struct exception_table_entry
  {
  	unsigned long insn, fixup;
  };
  
  #endif /* __ASM_AVR32_UACCESS_H */