2012-03-05 19:49:32 +08:00
|
|
|
/*
|
|
|
|
* Based on arch/arm/lib/clear_user.S
|
|
|
|
*
|
|
|
|
* Copyright (C) 2012 ARM Ltd.
|
|
|
|
*
|
|
|
|
* 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.
|
|
|
|
*
|
|
|
|
* This program is distributed in the hope that it will be useful,
|
|
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
* GNU General Public License for more details.
|
|
|
|
*
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
*/
|
|
|
|
#include <linux/linkage.h>
|
2015-07-23 02:05:54 +08:00
|
|
|
|
|
|
|
#include <asm/alternative.h>
|
2012-03-05 19:49:32 +08:00
|
|
|
#include <asm/assembler.h>
|
2015-07-23 02:05:54 +08:00
|
|
|
#include <asm/cpufeature.h>
|
|
|
|
#include <asm/sysreg.h>
|
2012-03-05 19:49:32 +08:00
|
|
|
|
|
|
|
.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
|
|
|
|
*
|
|
|
|
* Alignment fixed up by hardware.
|
|
|
|
*/
|
|
|
|
ENTRY(__clear_user)
|
2016-02-05 22:58:50 +08:00
|
|
|
ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
|
2015-07-23 02:05:54 +08:00
|
|
|
CONFIG_ARM64_PAN)
|
2012-03-05 19:49:32 +08:00
|
|
|
mov x2, x1 // save the size for fixup return
|
|
|
|
subs x1, x1, #8
|
|
|
|
b.mi 2f
|
|
|
|
1:
|
2016-02-05 22:58:48 +08:00
|
|
|
uao_user_alternative 9f, str, sttr, xzr, x0, 8
|
2012-03-05 19:49:32 +08:00
|
|
|
subs x1, x1, #8
|
|
|
|
b.pl 1b
|
|
|
|
2: adds x1, x1, #4
|
|
|
|
b.mi 3f
|
2016-02-05 22:58:48 +08:00
|
|
|
uao_user_alternative 9f, str, sttr, wzr, x0, 4
|
2012-03-05 19:49:32 +08:00
|
|
|
sub x1, x1, #4
|
|
|
|
3: adds x1, x1, #2
|
|
|
|
b.mi 4f
|
2016-02-05 22:58:48 +08:00
|
|
|
uao_user_alternative 9f, strh, sttrh, wzr, x0, 2
|
2012-03-05 19:49:32 +08:00
|
|
|
sub x1, x1, #2
|
|
|
|
4: adds x1, x1, #1
|
|
|
|
b.mi 5f
|
2016-02-05 22:58:48 +08:00
|
|
|
uao_user_alternative 9f, strb, sttrb, wzr, x0, 0
|
2012-03-05 19:49:32 +08:00
|
|
|
5: mov x0, #0
|
2016-02-05 22:58:50 +08:00
|
|
|
ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
|
2015-07-23 02:05:54 +08:00
|
|
|
CONFIG_ARM64_PAN)
|
2012-03-05 19:49:32 +08:00
|
|
|
ret
|
|
|
|
ENDPROC(__clear_user)
|
|
|
|
|
|
|
|
.section .fixup,"ax"
|
|
|
|
.align 2
|
|
|
|
9: mov x0, x2 // return the original size
|
|
|
|
ret
|
|
|
|
.previous
|