kernel/arch/arm64/lib/copy_page.S
2024-07-22 17:22:30 +08:00

80 lines
1.7 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 ARM Ltd.
*/
#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
*/
SYM_FUNC_START_PI(copy_page)
alternative_if ARM64_HAS_NO_HW_PREFETCH
// Prefetch three cache lines ahead.
prfm pldl1strm, [x1, #128]
prfm pldl1strm, [x1, #256]
prfm pldl1strm, [x1, #384]
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]
add x0, x0, #256
add x1, x1, #128
1:
tst x0, #(PAGE_SIZE - 1)
alternative_if ARM64_HAS_NO_HW_PREFETCH
prfm pldl1strm, [x1, #384]
alternative_else_nop_endif
stnp x2, x3, [x0, #-256]
ldp x2, x3, [x1]
stnp x4, x5, [x0, #16 - 256]
ldp x4, x5, [x1, #16]
stnp x6, x7, [x0, #32 - 256]
ldp x6, x7, [x1, #32]
stnp x8, x9, [x0, #48 - 256]
ldp x8, x9, [x1, #48]
stnp x10, x11, [x0, #64 - 256]
ldp x10, x11, [x1, #64]
stnp x12, x13, [x0, #80 - 256]
ldp x12, x13, [x1, #80]
stnp x14, x15, [x0, #96 - 256]
ldp x14, x15, [x1, #96]
stnp x16, x17, [x0, #112 - 256]
ldp x16, x17, [x1, #112]
add x0, x0, #128
add x1, x1, #128
b.ne 1b
stnp x2, x3, [x0, #-256]
stnp x4, x5, [x0, #16 - 256]
stnp x6, x7, [x0, #32 - 256]
stnp x8, x9, [x0, #48 - 256]
stnp x10, x11, [x0, #64 - 256]
stnp x12, x13, [x0, #80 - 256]
stnp x14, x15, [x0, #96 - 256]
stnp x16, x17, [x0, #112 - 256]
ret
SYM_FUNC_END_PI(copy_page)
EXPORT_SYMBOL(copy_page)