1/*
  2 * Copy to/from userspace with optional address space checking.
  3 *
  4 * Copyright 2004-2006 Atmel Corporation
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License version 2 as
  8 * published by the Free Software Foundation.
  9 */
 10#include <asm/page.h>
 11#include <asm/thread_info.h>
 12#include <asm/asm.h>
 13
 14	/*
 15	 * __kernel_size_t
 16	 * __copy_user(void *to, const void *from, __kernel_size_t n)
 17	 *
 18	 * Returns the number of bytes not copied. Might be off by
 19	 * max 3 bytes if we get a fault in the main loop.
 20	 *
 21	 * The address-space checking functions simply fall through to
 22	 * the non-checking version.
 23	 */
 24	.text
 25	.align	1
 26	.global	copy_from_user
 27	.type	copy_from_user, @function
 28copy_from_user:
 29	branch_if_kernel r8, __copy_user
 30	ret_if_privileged r8, r11, r10, r10
 31	rjmp	__copy_user
 32	.size	copy_from_user, . - copy_from_user
 33
 34	.global	copy_to_user
 35	.type	copy_to_user, @function
 36copy_to_user:
 37	branch_if_kernel r8, __copy_user
 38	ret_if_privileged r8, r12, r10, r10
 39	.size	copy_to_user, . - copy_to_user
 40
 41	.global	__copy_user
 42	.type	__copy_user, @function
 43__copy_user:
 44	mov	r9, r11
 45	andl	r9, 3, COH
 46	brne	6f
 47
 48	/* At this point, from is word-aligned */
 491:	sub	r10, 4
 50	brlt	3f
 51
 522:
 5310:	ld.w	r8, r11++
 5411:	st.w	r12++, r8
 55	sub	r10, 4
 56	brge	2b
 57
 583:	sub	r10, -4
 59	reteq	0
 60
 61	/*
 62	 * Handle unaligned count. Need to be careful with r10 here so
 63	 * that we return the correct value even if we get a fault
 64	 */
 654:
 6620:	ld.ub	r8, r11++
 6721:	st.b	r12++, r8
 68	sub	r10, 1
 69	reteq	0
 7022:	ld.ub	r8, r11++
 7123:	st.b	r12++, r8
 72	sub	r10, 1
 73	reteq	0
 7424:	ld.ub	r8, r11++
 7525:	st.b	r12++, r8
 76	retal	0
 77
 78	/* Handle unaligned from-pointer */
 796:	cp.w	r10, 4
 80	brlt	4b
 81	rsub	r9, r9, 4
 82
 8330:	ld.ub	r8, r11++
 8431:	st.b	r12++, r8
 85	sub	r10, 1
 86	sub	r9, 1
 87	breq	1b
 8832:	ld.ub	r8, r11++
 8933:	st.b	r12++, r8
 90	sub	r10, 1
 91	sub	r9, 1
 92	breq	1b
 9334:	ld.ub	r8, r11++
 9435:	st.b	r12++, r8
 95	sub	r10, 1
 96	rjmp	1b
 97	.size	__copy_user, . - __copy_user
 98
 99	.section .fixup,"ax"
100	.align	1
10119:	sub	r10, -4
10229:	retal	r10
103
104	.section __ex_table,"a"
105	.align	2
106	.long	10b, 19b
107	.long	11b, 19b
108	.long	20b, 29b
109	.long	21b, 29b
110	.long	22b, 29b
111	.long	23b, 29b
112	.long	24b, 29b
113	.long	25b, 29b
114	.long	30b, 29b
115	.long	31b, 29b
116	.long	32b, 29b
117	.long	33b, 29b
118	.long	34b, 29b
119	.long	35b, 29b