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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/avr32/lib/strnlen_user.S
10817 views
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/*

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 * Copy to/from userspace with optional address space checking.

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 *

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 * Copyright 2004-2006 Atmel Corporation

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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 <asm/page.h>

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#include <asm/thread_info.h>

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#include <asm/processor.h>

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#include <asm/asm.h>

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	.text

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	.align	1

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	.global	strnlen_user

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	.type	strnlen_user, "function"

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strnlen_user:

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	branch_if_kernel r8, __strnlen_user

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	sub	r8, r11, 1

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	add	r8, r12

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	retcs	0

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	brmi	adjust_length	/* do a closer inspection */

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	.global	__strnlen_user

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	.type	__strnlen_user, "function"

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__strnlen_user:

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	mov	r10, r12

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10:	ld.ub	r8, r12++

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	cp.w	r8, 0

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	breq	2f

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	sub	r11, 1

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	brne	10b

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	sub	r12, -1

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2:	sub	r12, r10

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	retal	r12

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	.type	adjust_length, "function"

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adjust_length:

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	cp.w	r12, 0		/* addr must always be < TASK_SIZE */

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	retmi	0

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	pushm	lr

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	lddpc	lr, _task_size

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	sub	r11, lr, r12

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	mov	r9, r11

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	call	__strnlen_user

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	cp.w	r12, r9

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	brgt	1f

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	popm	pc

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1:	popm	pc, r12=0

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	.align	2

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_task_size:

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	.long	TASK_SIZE

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	.section .fixup, "ax"

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	.align	1

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19:	retal	0

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	.section __ex_table, "a"

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	.align	2

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	.long	10b, 19b

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