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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arm64/lib/copy_from_user.S
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/* SPDX-License-Identifier: GPL-2.0-only */

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/*

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 * Copyright (C) 2012 ARM Ltd.

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 */

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#include <linux/linkage.h>

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#include <asm/asm-uaccess.h>

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#include <asm/assembler.h>

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#include <asm/cache.h>

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/*

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 * Copy from user space to a kernel buffer (alignment handled by the hardware)

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 *

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 * Parameters:

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 *	x0 - to

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 *	x1 - from

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 *	x2 - n

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 * Returns:

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 *	x0 - bytes not copied

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 */

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	.macro ldrb1 reg, ptr, val

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	user_ldst 9998f, ldtrb, \reg, \ptr, \val

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	.endm

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	.macro strb1 reg, ptr, val

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	strb \reg, [\ptr], \val

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	.endm

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	.macro ldrh1 reg, ptr, val

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	user_ldst 9997f, ldtrh, \reg, \ptr, \val

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	.endm

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	.macro strh1 reg, ptr, val

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	strh \reg, [\ptr], \val

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	.endm

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	.macro ldr1 reg, ptr, val

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	user_ldst 9997f, ldtr, \reg, \ptr, \val

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	.endm

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	.macro str1 reg, ptr, val

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	str \reg, [\ptr], \val

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	.endm

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	.macro ldp1 reg1, reg2, ptr, val

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	user_ldp 9997f, \reg1, \reg2, \ptr, \val

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	.endm

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	.macro stp1 reg1, reg2, ptr, val

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	stp \reg1, \reg2, [\ptr], \val

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	.endm

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	.macro cpy1 dst, src, count

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	.arch_extension mops

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	USER_CPY(9997f, 0, cpyfprt [\dst]!, [\src]!, \count!)

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	USER_CPY(9996f, 0, cpyfmrt [\dst]!, [\src]!, \count!)

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	USER_CPY(9996f, 0, cpyfert [\dst]!, [\src]!, \count!)

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	.endm

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end	.req	x5

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srcin	.req	x15

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SYM_FUNC_START(__arch_copy_from_user)

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	add	end, x0, x2

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	mov	srcin, x1

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#include "copy_template.S"

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	mov	x0, #0				// Nothing to copy

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	ret

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	// Exception fixups

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9996:	b.cs	9997f

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	// Registers are in Option A format

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	add	dst, dst, count

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9997:	cmp	dst, dstin

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	b.ne	9998f

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	// Before being absolutely sure we couldn't copy anything, try harder

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USER(9998f, ldtrb tmp1w, [srcin])

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	strb	tmp1w, [dst], #1

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9998:	sub	x0, end, dst			// bytes not copied

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	ret

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SYM_FUNC_END(__arch_copy_from_user)

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EXPORT_SYMBOL(__arch_copy_from_user)

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