1 files changed, 61 insertions, 0 deletions
diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S
new file mode 100644
index 00000000000..a0aeeb9b7a2
--- /dev/null
+++ b/arch/arm64/lib/copy_to_user.S
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Copy to user space from a kernel buffer (alignment handled by the hardware)
+ *
+ * Parameters:
+ *	x0 - to
+ *	x1 - from
+ *	x2 - n
+ * Returns:
+ *	x0 - bytes not copied
+ */
+ENTRY(__copy_to_user)
+	add	x4, x0, x2			// upper user buffer boundary
+	subs	x2, x2, #8
+	b.mi	2f
+1:
+	ldr	x3, [x1], #8
+	subs	x2, x2, #8
+USER(9f, str	x3, [x0], #8	)
+	b.pl	1b
+2:	adds	x2, x2, #4
+	b.mi	3f
+	ldr	w3, [x1], #4
+	sub	x2, x2, #4
+USER(9f, str	w3, [x0], #4	)
+3:	adds	x2, x2, #2
+	b.mi	4f
+	ldrh	w3, [x1], #2
+	sub	x2, x2, #2
+USER(9f, strh	w3, [x0], #2	)
+4:	adds	x2, x2, #1
+	b.mi	5f
+	ldrb	w3, [x1]
+USER(9f, strb	w3, [x0]	)
+5:	mov	x0, #0
+	ret
+ENDPROC(__copy_to_user)
+
+	.section .fixup,"ax"
+	.align	2
+9:	sub	x0, x4, x0			// bytes not copied
+	ret
+	.previous