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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/arm/lib/copy_from_user.S
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/*

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 *  linux/arch/arm/lib/copy_from_user.S

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 *

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 *  Author:	Nicolas Pitre

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 *  Created:	Sep 29, 2005

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 *  Copyright:	MontaVista Software, Inc.

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 *

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 *  This program is free software; you can redistribute it and/or modify

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 *  it under the terms of the GNU General Public License version 2 as

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 *  published by the Free Software Foundation.

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 */

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#include <linux/linkage.h>

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#include <asm/assembler.h>

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/*

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 * Prototype:

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 *

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 *	size_t __copy_from_user(void *to, const void *from, size_t n)

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 *

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 * Purpose:

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 *

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 *	copy a block to kernel memory from user memory

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 *

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 * Params:

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 *

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 *	to = kernel memory

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 *	from = user memory

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 *	n = number of bytes to copy

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 *

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 * Return value:

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 *

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 *	Number of bytes NOT copied.

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 */

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#ifndef CONFIG_THUMB2_KERNEL

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#define LDR1W_SHIFT	0

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#else

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#define LDR1W_SHIFT	1

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#endif

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#define STR1W_SHIFT	0

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	.macro ldr1w ptr reg abort

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	ldrusr	\reg, \ptr, 4, abort=\abort

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	.endm

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	.macro ldr4w ptr reg1 reg2 reg3 reg4 abort

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	ldr1w \ptr, \reg1, \abort

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	ldr1w \ptr, \reg2, \abort

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	ldr1w \ptr, \reg3, \abort

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	ldr1w \ptr, \reg4, \abort

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	.endm

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	.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort

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	ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort

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	ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort

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	.endm

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	.macro ldr1b ptr reg cond=al abort

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	ldrusr	\reg, \ptr, 1, \cond, abort=\abort

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	.endm

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	.macro str1w ptr reg abort

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	W(str) \reg, [\ptr], #4

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	.endm

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	.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort

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	stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}

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	.endm

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	.macro str1b ptr reg cond=al abort

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	str\cond\()b \reg, [\ptr], #1

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	.endm

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	.macro enter reg1 reg2

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	mov	r3, #0

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	stmdb	sp!, {r0, r2, r3, \reg1, \reg2}

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	.endm

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	.macro exit reg1 reg2

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	add	sp, sp, #8

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	ldmfd	sp!, {r0, \reg1, \reg2}

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	.endm

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	.text

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ENTRY(__copy_from_user)

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#include "copy_template.S"

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ENDPROC(__copy_from_user)

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	.pushsection .fixup,"ax"

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	.align 0

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	copy_abort_preamble

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	ldmfd	sp!, {r1, r2}

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	sub	r3, r0, r1

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	rsb	r1, r3, r2

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	str	r1, [sp]

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	bl	__memzero

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	ldr	r0, [sp], #4

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	copy_abort_end

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	.popsection

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