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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/avr32/lib/copy_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/asm.h>

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	/*

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	 * __kernel_size_t

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	 * __copy_user(void *to, const void *from, __kernel_size_t n)

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	 *

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	 * Returns the number of bytes not copied. Might be off by

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	 * max 3 bytes if we get a fault in the main loop.

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	 *

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	 * The address-space checking functions simply fall through to

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	 * the non-checking version.

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	 */

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	.text

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	.align	1

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	.global	copy_from_user

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	.type	copy_from_user, @function

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copy_from_user:

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	branch_if_kernel r8, __copy_user

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	ret_if_privileged r8, r11, r10, r10

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	rjmp	__copy_user

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	.size	copy_from_user, . - copy_from_user

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	.global	copy_to_user

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	.type	copy_to_user, @function

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copy_to_user:

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	branch_if_kernel r8, __copy_user

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	ret_if_privileged r8, r12, r10, r10

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	.size	copy_to_user, . - copy_to_user

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	.global	__copy_user

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	.type	__copy_user, @function

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__copy_user:

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	mov	r9, r11

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	andl	r9, 3, COH

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	brne	6f

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	/* At this point, from is word-aligned */

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1:	sub	r10, 4

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	brlt	3f

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2:

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10:	ld.w	r8, r11++

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11:	st.w	r12++, r8

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	sub	r10, 4

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	brge	2b

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3:	sub	r10, -4

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	reteq	0

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	/*

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	 * Handle unaligned count. Need to be careful with r10 here so

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	 * that we return the correct value even if we get a fault

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	 */

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4:

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20:	ld.ub	r8, r11++

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21:	st.b	r12++, r8

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	sub	r10, 1

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	reteq	0

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22:	ld.ub	r8, r11++

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23:	st.b	r12++, r8

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	sub	r10, 1

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	reteq	0

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24:	ld.ub	r8, r11++

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25:	st.b	r12++, r8

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	retal	0

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	/* Handle unaligned from-pointer */

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6:	cp.w	r10, 4

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	brlt	4b

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	rsub	r9, r9, 4

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30:	ld.ub	r8, r11++

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31:	st.b	r12++, r8

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	sub	r10, 1

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	sub	r9, 1

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	breq	1b

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32:	ld.ub	r8, r11++

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33:	st.b	r12++, r8

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	sub	r10, 1

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	sub	r9, 1

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	breq	1b

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34:	ld.ub	r8, r11++

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35:	st.b	r12++, r8

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	sub	r10, 1

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	rjmp	1b

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	.size	__copy_user, . - __copy_user

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	.section .fixup,"ax"

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	.align	1

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19:	sub	r10, -4

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29:	retal	r10

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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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	.long	11b, 19b

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	.long	20b, 29b

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	.long	21b, 29b

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	.long	22b, 29b

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	.long	23b, 29b

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	.long	24b, 29b

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	.long	25b, 29b

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	.long	30b, 29b

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	.long	31b, 29b

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	.long	32b, 29b

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	.long	33b, 29b

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	.long	34b, 29b

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	.long	35b, 29b

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