From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/avr32/lib/copy_user.S | 119 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 arch/avr32/lib/copy_user.S

(limited to 'arch/avr32/lib/copy_user.S')

diff --git a/arch/avr32/lib/copy_user.S b/arch/avr32/lib/copy_user.S
new file mode 100644
index 000000000..ea59c04b0
--- /dev/null
+++ b/arch/avr32/lib/copy_user.S
@@ -0,0 +1,119 @@
+/*
+ * Copy to/from userspace with optional address space checking.
+ *
+ * Copyright 2004-2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <asm/page.h>
+#include <asm/thread_info.h>
+#include <asm/asm.h>
+
+	/*
+	 * __kernel_size_t
+	 * __copy_user(void *to, const void *from, __kernel_size_t n)
+	 *
+	 * Returns the number of bytes not copied. Might be off by
+	 * max 3 bytes if we get a fault in the main loop.
+	 *
+	 * The address-space checking functions simply fall through to
+	 * the non-checking version.
+	 */
+	.text
+	.align	1
+	.global	copy_from_user
+	.type	copy_from_user, @function
+copy_from_user:
+	branch_if_kernel r8, __copy_user
+	ret_if_privileged r8, r11, r10, r10
+	rjmp	__copy_user
+	.size	copy_from_user, . - copy_from_user
+
+	.global	copy_to_user
+	.type	copy_to_user, @function
+copy_to_user:
+	branch_if_kernel r8, __copy_user
+	ret_if_privileged r8, r12, r10, r10
+	.size	copy_to_user, . - copy_to_user
+
+	.global	__copy_user
+	.type	__copy_user, @function
+__copy_user:
+	mov	r9, r11
+	andl	r9, 3, COH
+	brne	6f
+
+	/* At this point, from is word-aligned */
+1:	sub	r10, 4
+	brlt	3f
+
+2:
+10:	ld.w	r8, r11++
+11:	st.w	r12++, r8
+	sub	r10, 4
+	brge	2b
+
+3:	sub	r10, -4
+	reteq	0
+
+	/*
+	 * Handle unaligned count. Need to be careful with r10 here so
+	 * that we return the correct value even if we get a fault
+	 */
+4:
+20:	ld.ub	r8, r11++
+21:	st.b	r12++, r8
+	sub	r10, 1
+	reteq	0
+22:	ld.ub	r8, r11++
+23:	st.b	r12++, r8
+	sub	r10, 1
+	reteq	0
+24:	ld.ub	r8, r11++
+25:	st.b	r12++, r8
+	retal	0
+
+	/* Handle unaligned from-pointer */
+6:	cp.w	r10, 4
+	brlt	4b
+	rsub	r9, r9, 4
+
+30:	ld.ub	r8, r11++
+31:	st.b	r12++, r8
+	sub	r10, 1
+	sub	r9, 1
+	breq	1b
+32:	ld.ub	r8, r11++
+33:	st.b	r12++, r8
+	sub	r10, 1
+	sub	r9, 1
+	breq	1b
+34:	ld.ub	r8, r11++
+35:	st.b	r12++, r8
+	sub	r10, 1
+	rjmp	1b
+	.size	__copy_user, . - __copy_user
+
+	.section .fixup,"ax"
+	.align	1
+19:	sub	r10, -4
+29:	retal	r10
+
+	.section __ex_table,"a"
+	.align	2
+	.long	10b, 19b
+	.long	11b, 19b
+	.long	20b, 29b
+	.long	21b, 29b
+	.long	22b, 29b
+	.long	23b, 29b
+	.long	24b, 29b
+	.long	25b, 29b
+	.long	30b, 29b
+	.long	31b, 29b
+	.long	32b, 29b
+	.long	33b, 29b
+	.long	34b, 29b
+	.long	35b, 29b
-- 
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