forked from mirrors/linux
77c93b2f23
This patch implements low-level uaccess libraries. Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn> Acked-by: Arnd Bergmann <arnd@arndb.de>
57 lines
1.3 KiB
ArmAsm
57 lines
1.3 KiB
ArmAsm
/*
|
|
* linux/arch/unicore32/lib/clear_user.S
|
|
*
|
|
* Code specific to PKUnity SoC and UniCore ISA
|
|
*
|
|
* Copyright (C) 2001-2010 GUAN Xue-tao
|
|
*
|
|
* 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.
|
|
*/
|
|
#include <linux/linkage.h>
|
|
#include <asm/assembler.h>
|
|
|
|
.text
|
|
|
|
/* Prototype: int __clear_user(void *addr, size_t sz)
|
|
* Purpose : clear some user memory
|
|
* Params : addr - user memory address to clear
|
|
* : sz - number of bytes to clear
|
|
* Returns : number of bytes NOT cleared
|
|
*/
|
|
WEAK(__clear_user)
|
|
stm.w (lr), [sp-]
|
|
stm.w (r1), [sp-]
|
|
mov r2, #0
|
|
csub.a r1, #4
|
|
bsl 2f
|
|
and.a ip, r0, #3
|
|
beq 1f
|
|
csub.a ip, #2
|
|
strusr r2, r0, 1
|
|
strusr r2, r0, 1, el
|
|
strusr r2, r0, 1, sl
|
|
rsub ip, ip, #4
|
|
sub r1, r1, ip @ 7 6 5 4 3 2 1
|
|
1: sub.a r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
|
|
strusr r2, r0, 4, ns, rept=2
|
|
bns 1b
|
|
add.a r1, r1, #4 @ 3 2 1 0 -1 -2 -3
|
|
strusr r2, r0, 4, ns
|
|
2: cand.a r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
|
|
strusr r2, r0, 1, ne, rept=2
|
|
cand.a r1, #1 @ x1 x0 x1 x0 x1 x0 x1
|
|
beq 3f
|
|
USER( stb.u r2, [r0])
|
|
3: mov r0, #0
|
|
ldm.w (r1), [sp]+
|
|
ldm.w (pc), [sp]+
|
|
ENDPROC(__clear_user)
|
|
|
|
.pushsection .fixup,"ax"
|
|
.align 0
|
|
9001: ldm.w (r0), [sp]+
|
|
ldm.w (pc), [sp]+
|
|
.popsection
|
|
|