/*
* 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);
}

#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.
*
* 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.
*
* 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.
*
* 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.
*
* 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 = (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 = (typeof(*(ptr)))__gu_val; \
__gu_err; \
})

#define __get_user_asm(suffix, __gu_val, ptr, __gu_err) \
asm volatile( \
"1: ld." suffix " %1, %3 \n" \
"2: \n" \
" .subsection 1 \n" \
"3: mov %0, %4 \n" \
" rjmp 2b \n" \
" .subsection 0 \n" \
" .section __ex_table, \"a\" \n" \
" .long 1b, 3b \n" \
" .previous \n" \
: "=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 \n" \
"2: \n" \
" .subsection 1 \n" \
"3: mov %0, %4 \n" \
" rjmp 2b \n" \
" .subsection 0 \n" \
" .section __ex_table, \"a\" \n" \
" .long 1b, 3b \n" \
" .previous \n" \
: "=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 */