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/*
* arch/mips/lib/strncpy_user.S
*
* 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.
*
* Copyright (c) 1996 by Ralf Baechle
*
* $Id: strncpy_user.S,v 1.3 1998/05/03 11:13:45 ralf Exp $
*/
#include <linux/errno.h>
#include <asm/asm.h>
#include <asm/offset.h>
#include <asm/regdef.h>
#define EX(insn,reg,addr,handler) \
9: insn reg, addr; \
.section __ex_table,"a"; \
PTR 9b, handler; \
.previous
/*
* Returns: -EFAULT if exception before terminator, N if the entire
* buffer filled, else strlen.
*/
/*
* Ugly special case have to check: we might get passed a user space
* pointer which wraps into the kernel space. We don't deal with that. If
* it happens at most some bytes of the exceptions handlers will be copied.
*/
LEAF(__strncpy_from_user_asm)
lw v0, THREAD_CURDS($28) # pointer ok?
subu v0, zero, v0
and v0, a1
nor v0, zero, v0
beqz v0, fault
EXPORT(__strncpy_from_user_nocheck_asm)
move v0,zero
move v1,a1
.set noreorder
1: EX(lbu, t0, (v1), fault)
LONG_ADDIU v1,1
beqz t0,2f
sb t0,(a0)
LONG_ADDIU v0,1
bne v0,a2,1b
LONG_ADDIU a0,1
.set reorder
2: LONG_ADDU t0,a1,v0
xor t0,a1
bltz t0,fault
jr ra # return n
END(__strncpy_from_user_asm)
fault: li v0,-EFAULT
jr ra
.section __ex_table,"a"
PTR 1b,fault
.previous
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