mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 07:36:56 +07:00
0aea86a217
This patch add support for various user access functions. These functions use the standard LDR/STR instructions and not the LDRT/STRT variants in order to allow kernel addresses (after set_fs(KERNEL_DS)). Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
59 lines
1.4 KiB
ArmAsm
59 lines
1.4 KiB
ArmAsm
/*
|
|
* 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>
|
|
#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
|
|
*
|
|
* Alignment fixed up by hardware.
|
|
*/
|
|
ENTRY(__clear_user)
|
|
mov x2, x1 // save the size for fixup return
|
|
subs x1, x1, #8
|
|
b.mi 2f
|
|
1:
|
|
USER(9f, str xzr, [x0], #8 )
|
|
subs x1, x1, #8
|
|
b.pl 1b
|
|
2: adds x1, x1, #4
|
|
b.mi 3f
|
|
USER(9f, str wzr, [x0], #4 )
|
|
sub x1, x1, #4
|
|
3: adds x1, x1, #2
|
|
b.mi 4f
|
|
USER(9f, strh wzr, [x0], #2 )
|
|
sub x1, x1, #2
|
|
4: adds x1, x1, #1
|
|
b.mi 5f
|
|
strb wzr, [x0]
|
|
5: mov x0, #0
|
|
ret
|
|
ENDPROC(__clear_user)
|
|
|
|
.section .fixup,"ax"
|
|
.align 2
|
|
9: mov x0, x2 // return the original size
|
|
ret
|
|
.previous
|