linux_dsm_epyc7002/arch/arm64/lib/copy_page.S
Mark Rutland 6ba3b554f5 arm64: use alternative auto-nop
Make use of the new alternative_if and alternative_else_nop_endif and
get rid of our homebew NOP sleds, making the code simpler to read.

Note that for cpu_do_switch_mm the ret has been moved out of the
alternative sequence, and in the default case there will be three
additional NOPs executed.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-09-12 10:46:07 +01:00

89 lines
2.0 KiB
ArmAsm

/*
* 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 <linux/const.h>
#include <asm/assembler.h>
#include <asm/page.h>
#include <asm/cpufeature.h>
#include <asm/alternative.h>
/*
* Copy a page from src to dest (both are page aligned)
*
* Parameters:
* x0 - dest
* x1 - src
*/
ENTRY(copy_page)
alternative_if ARM64_HAS_NO_HW_PREFETCH
# Prefetch two cache lines ahead.
prfm pldl1strm, [x1, #128]
prfm pldl1strm, [x1, #256]
alternative_else_nop_endif
ldp x2, x3, [x1]
ldp x4, x5, [x1, #16]
ldp x6, x7, [x1, #32]
ldp x8, x9, [x1, #48]
ldp x10, x11, [x1, #64]
ldp x12, x13, [x1, #80]
ldp x14, x15, [x1, #96]
ldp x16, x17, [x1, #112]
mov x18, #(PAGE_SIZE - 128)
add x1, x1, #128
1:
subs x18, x18, #128
alternative_if ARM64_HAS_NO_HW_PREFETCH
prfm pldl1strm, [x1, #384]
alternative_else_nop_endif
stnp x2, x3, [x0]
ldp x2, x3, [x1]
stnp x4, x5, [x0, #16]
ldp x4, x5, [x1, #16]
stnp x6, x7, [x0, #32]
ldp x6, x7, [x1, #32]
stnp x8, x9, [x0, #48]
ldp x8, x9, [x1, #48]
stnp x10, x11, [x0, #64]
ldp x10, x11, [x1, #64]
stnp x12, x13, [x0, #80]
ldp x12, x13, [x1, #80]
stnp x14, x15, [x0, #96]
ldp x14, x15, [x1, #96]
stnp x16, x17, [x0, #112]
ldp x16, x17, [x1, #112]
add x0, x0, #128
add x1, x1, #128
b.gt 1b
stnp x2, x3, [x0]
stnp x4, x5, [x0, #16]
stnp x6, x7, [x0, #32]
stnp x8, x9, [x0, #48]
stnp x10, x11, [x0, #64]
stnp x12, x13, [x0, #80]
stnp x14, x15, [x0, #96]
stnp x16, x17, [x0, #112]
ret
ENDPROC(copy_page)