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

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

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 *

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 *  Copyright (C) 1995-1998 Russell King

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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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 * 27/03/03 Ian Molton Clean up CONFIG_CPU

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 *

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 */

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#include <linux/linkage.h>

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#include <asm/assembler.h>

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#include <asm/errno.h>

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#include <asm/asm-offsets.h>

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		.text

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		.macro	save_regs

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		stmfd	sp!, {r1, r2, r4 - r8, lr}

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		.endm

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		.macro	load_regs

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		ldmfd	sp!, {r1, r2, r4 - r8, pc}

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		.endm

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		.macro	load1b,	reg1

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		ldrusr	\reg1, r0, 1

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		.endm

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		.macro	load2b, reg1, reg2

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		ldrusr	\reg1, r0, 1

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		ldrusr	\reg2, r0, 1

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		.endm

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		.macro	load1l, reg1

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		ldrusr	\reg1, r0, 4

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		.endm

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		.macro	load2l, reg1, reg2

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		ldrusr	\reg1, r0, 4

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		ldrusr	\reg2, r0, 4

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		.endm

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		.macro	load4l, reg1, reg2, reg3, reg4

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		ldrusr	\reg1, r0, 4

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		ldrusr	\reg2, r0, 4

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		ldrusr	\reg3, r0, 4

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		ldrusr	\reg4, r0, 4

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		.endm

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/*

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 * unsigned int

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 * csum_partial_copy_from_user(const char *src, char *dst, int len, int sum, int *err_ptr)

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 *  r0 = src, r1 = dst, r2 = len, r3 = sum, [sp] = *err_ptr

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 *  Returns : r0 = checksum, [[sp, #0], #0] = 0 or -EFAULT

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 */

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#define FN_ENTRY	ENTRY(csum_partial_copy_from_user)

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#define FN_EXIT		ENDPROC(csum_partial_copy_from_user)

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#include "csumpartialcopygeneric.S"

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/*

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 * FIXME: minor buglet here

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 * We don't return the checksum for the data present in the buffer.  To do

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 * so properly, we would have to add in whatever registers were loaded before

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 * the fault, which, with the current asm above is not predictable.

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 */

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		.pushsection .fixup,"ax"

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		.align	4

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9001:		mov	r4, #-EFAULT

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		ldr	r5, [sp, #8*4]		@ *err_ptr

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		str	r4, [r5]

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		ldmia	sp, {r1, r2}		@ retrieve dst, len

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		add	r2, r2, r1

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		mov	r0, #0			@ zero the buffer

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9002:		teq	r2, r1

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		strneb	r0, [r1], #1

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		bne	9002b

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		load_regs

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		.popsection

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