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/* $Id: strncpy_user.S,v 1.2 1999/11/19 20:35:23 ralf Exp $
*
* 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, 1999 by Ralf Baechle
*/
#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)
ld v0, THREAD_CURDS($28) # pointer ok?
and v0, a1
bltz v0, fault
FEXPORT(__strncpy_from_user_nocheck_asm)
move v0, zero
move v1, a1
.set noreorder
1: EX(lbu, ta0, (v1), fault)
daddiu v1, 1
beqz ta0, 2f
sb ta0, (a0)
daddiu v0, 1
bne v0, a2, 1b
daddiu a0, 1
.set reorder
2: daddu ta0, a1, v0
xor ta0, a1
bltz ta0, 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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