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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/lib/copy_page_64.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/* Written 2003 by Andi Kleen, based on a kernel by Evandro Menezes */

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#include <linux/export.h>

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#include <linux/linkage.h>

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#include <linux/cfi_types.h>

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#include <asm/cpufeatures.h>

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#include <asm/alternative.h>

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/*

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 * Some CPUs run faster using the string copy instructions (sane microcode).

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 * It is also a lot simpler. Use this when possible. But, don't use streaming

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 * copy unless the CPU indicates X86_FEATURE_REP_GOOD. Could vary the

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 * prefetch distance based on SMP/UP.

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 */

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	ALIGN

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SYM_TYPED_FUNC_START(copy_page)

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	ALTERNATIVE "jmp copy_page_regs", "", X86_FEATURE_REP_GOOD

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	movl	$4096/8, %ecx

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	rep	movsq

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	RET

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SYM_FUNC_END(copy_page)

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EXPORT_SYMBOL(copy_page)

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SYM_FUNC_START_LOCAL(copy_page_regs)

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	subq	$2*8,	%rsp

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	movq	%rbx,	(%rsp)

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	movq	%r12,	1*8(%rsp)

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	movl	$(4096/64)-5,	%ecx

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	.p2align 4

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.Loop64:

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	dec	%rcx

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	movq	0x8*0(%rsi), %rax

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	movq	0x8*1(%rsi), %rbx

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	movq	0x8*2(%rsi), %rdx

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	movq	0x8*3(%rsi), %r8

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	movq	0x8*4(%rsi), %r9

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	movq	0x8*5(%rsi), %r10

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	movq	0x8*6(%rsi), %r11

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	movq	0x8*7(%rsi), %r12

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	prefetcht0 5*64(%rsi)

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	movq	%rax, 0x8*0(%rdi)

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	movq	%rbx, 0x8*1(%rdi)

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	movq	%rdx, 0x8*2(%rdi)

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	movq	%r8,  0x8*3(%rdi)

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	movq	%r9,  0x8*4(%rdi)

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	movq	%r10, 0x8*5(%rdi)

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	movq	%r11, 0x8*6(%rdi)

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	movq	%r12, 0x8*7(%rdi)

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	leaq	64 (%rsi), %rsi

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	leaq	64 (%rdi), %rdi

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	jnz	.Loop64

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	movl	$5, %ecx

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	.p2align 4

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.Loop2:

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	decl	%ecx

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	movq	0x8*0(%rsi), %rax

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	movq	0x8*1(%rsi), %rbx

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	movq	0x8*2(%rsi), %rdx

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	movq	0x8*3(%rsi), %r8

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	movq	0x8*4(%rsi), %r9

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	movq	0x8*5(%rsi), %r10

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	movq	0x8*6(%rsi), %r11

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	movq	0x8*7(%rsi), %r12

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	movq	%rax, 0x8*0(%rdi)

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	movq	%rbx, 0x8*1(%rdi)

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	movq	%rdx, 0x8*2(%rdi)

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	movq	%r8,  0x8*3(%rdi)

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	movq	%r9,  0x8*4(%rdi)

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	movq	%r10, 0x8*5(%rdi)

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	movq	%r11, 0x8*6(%rdi)

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	movq	%r12, 0x8*7(%rdi)

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	leaq	64(%rdi), %rdi

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	leaq	64(%rsi), %rsi

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	jnz	.Loop2

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	movq	(%rsp), %rbx

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	movq	1*8(%rsp), %r12

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	addq	$2*8, %rsp

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	RET

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SYM_FUNC_END(copy_page_regs)

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