/*
* User space memory access functions for Nios II
*
* Copyright (C) 2010-2011, Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2009, Wind River Systems Inc
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#ifndef _ASM_NIOS2_UACCESS_H
#define _ASM_NIOS2_UACCESS_H
#include <linux/errno.h>
#include <linux/thread_info.h>
#include <linux/string.h>
#include <asm/page.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/*
* The exception table consists of pairs of addresses: the first is the
* address of an instruction that is allowed to fault, and the second is
* the address at which the program should continue. No registers are
* modified, so it is entirely up to the continuation code to figure out
* what to do.
*
* All the routines below use bits of fixup code that are out of line
* with the main instruction path. This means when everything is well,
* we don't even have to jump over them. Further, they do not intrude
* on our cache or tlb entries.
*/
struct exception_table_entry {
unsigned long insn;
unsigned long fixup;
};
extern int fixup_exception(struct pt_regs *regs);
/*
* Segment stuff
*/
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#define USER_DS MAKE_MM_SEG(0x80000000UL)
#define KERNEL_DS MAKE_MM_SEG(0)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(seg) (current_thread_info()->addr_limit = (seg))
#define segment_eq(a, b) ((a).seg == (b).seg)
#define __access_ok(addr, len) \
(((signed long)(((long)get_fs().seg) & \
((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0)
#define access_ok(type, addr, len) \
likely(__access_ok((unsigned long)(addr), (unsigned long)(len)))
# define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n"
/*
* Zero Userspace
*/
static inline unsigned long __must_check __clear_user(void __user *to,
unsigned long n)
{
__asm__ __volatile__ (
"1: stb zero, 0(%1)\n"
" addi %0, %0, -1\n"
" addi %1, %1, 1\n"
" bne %0, zero, 1b\n"
"2:\n"
__EX_TABLE_SECTION
".word 1b, 2b\n"
".previous\n"
: "=r" (n), "=r" (to)
: "0" (n), "1" (to)
);
return n;
}
static inline unsigned long __must_check clear_user(void __user *to,
unsigned long n)
{
if (!access_ok(VERIFY_WRITE, to, n))
return n;
return __clear_user(to, n);
}
extern long __copy_from_user(void *to, const void __user *from,
unsigned long n);
extern long __copy_to_user(void __user *to, const void *from, unsigned long n);
static inline long copy_from_user(void *to, const void __user *from,
unsigned long n)
{
if (!access_ok(VERIFY_READ, from, n))
return n;
return __copy_from_user(to, from, n);
}
static inline long copy_to_user(void __user *to, const void *from,
unsigned long n)
{
if (!access_ok(VERIFY_WRITE, to, n))
return n;
return __copy_to_user(to, from, n);
}
extern long strncpy_from_user(char *__to, const char __user *__from,
long __len);
extern long strnlen_user(const char __user *s, long n);
#define __copy_from_user_inatomic __copy_from_user
#define __copy_to_user_inatomic __copy_to_user
/* Optimized macros */
#define __get_user_asm(val, insn, addr, err) \
{ \
__asm__ __volatile__( \
" movi %0, %3\n" \
"1: " insn " %1, 0(%2)\n" \
" movi %0, 0\n" \
"2:\n" \
" .section __ex_table,\"a\"\n" \
" .word 1b, 2b\n" \
" .previous" \
: "=&r" (err), "=r" (val) \
: "r" (addr), "i" (-EFAULT)); \
}
#define __get_user_unknown(val, size, ptr, err) do { \
err = 0; \
if (copy_from_user(&(val), ptr, size)) { \
err = -EFAULT; \
} \
} while (0)
#define __get_user_common(val, size, ptr, err) \
do { \
switch (size) { \
case 1: \
__get_user_asm(val, "ldbu", ptr, err); \
break; \
case 2: \
__get_user_asm(val, "ldhu", ptr, err); \
break; \
case 4: \
__get_user_asm(val, "ldw", ptr, err); \
break; \
default: \
__get_user_unknown(val, size, ptr, err); \
break; \
} \
} while (0)
#define __get_user(x, ptr) \
({ \
long __gu_err = -EFAULT; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
unsigned long __gu_val; \
__get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
(x) = (__force __typeof__(x))__gu_val; \
__gu_err; \
})
#define get_user(x, ptr) \
({ \
long __gu_err = -EFAULT; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
unsigned long __gu_val = 0; \
if (access_ok(VERIFY_READ, __gu_ptr, sizeof(*__gu_ptr))) \
__get_user_common(__gu_val, sizeof(*__gu_ptr), \
__gu_ptr, __gu_err); \
(x) = (__force __typeof__(x))__gu_val; \
__gu_err; \
})
#define __put_user_asm(val, insn, ptr, err) \
{ \
__asm__ __volatile__( \
" movi %0, %3\n" \
"1: " insn " %1, 0(%2)\n" \
" movi %0, 0\n" \
"2:\n" \
" .section __ex_table,\"a\"\n" \
" .word 1b, 2b\n" \
" .previous\n" \
: "=&r" (err) \
: "r" (val), "r" (ptr), "i" (-EFAULT)); \
}
#define put_user(x, ptr) \
({ \
long __pu_err = -EFAULT; \
__typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
__typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x); \
if (access_ok(VERIFY_WRITE, __pu_ptr, sizeof(*__pu_ptr))) { \
switch (sizeof(*__pu_ptr)) { \
case 1: \
__put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
break; \
case 2: \
__put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
break; \
case 4: \
__put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
break; \
default: \
/* XXX: This looks wrong... */ \
__pu_err = 0; \
if (copy_to_user(__pu_ptr, &(__pu_val), \
sizeof(*__pu_ptr))) \
__pu_err = -EFAULT; \
break; \
} \
} \
__pu_err; \
})
#define __put_user(x, ptr) put_user(x, ptr)
#endif /* _ASM_NIOS2_UACCESS_H */