1 files changed, 73 insertions, 0 deletions
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
new file mode 100644
index 000000000..34e317907
--- /dev/null
+++ b/arch/arm64/lib/copy_from_user.S
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/asm-uaccess.h>
+#include <asm/assembler.h>
+#include <asm/cache.h>
+
+/*
+ * Copy from user space to a kernel buffer (alignment handled by the hardware)
+ *
+ * Parameters:
+ *	x0 - to
+ *	x1 - from
+ *	x2 - n
+ * Returns:
+ *	x0 - bytes not copied
+ */
+
+	.macro ldrb1 reg, ptr, val
+	user_ldst 9998f, ldtrb, \reg, \ptr, \val
+	.endm
+
+	.macro strb1 reg, ptr, val
+	strb \reg, [\ptr], \val
+	.endm
+
+	.macro ldrh1 reg, ptr, val
+	user_ldst 9997f, ldtrh, \reg, \ptr, \val
+	.endm
+
+	.macro strh1 reg, ptr, val
+	strh \reg, [\ptr], \val
+	.endm
+
+	.macro ldr1 reg, ptr, val
+	user_ldst 9997f, ldtr, \reg, \ptr, \val
+	.endm
+
+	.macro str1 reg, ptr, val
+	str \reg, [\ptr], \val
+	.endm
+
+	.macro ldp1 reg1, reg2, ptr, val
+	user_ldp 9997f, \reg1, \reg2, \ptr, \val
+	.endm
+
+	.macro stp1 reg1, reg2, ptr, val
+	stp \reg1, \reg2, [\ptr], \val
+	.endm
+
+end	.req	x5
+srcin	.req	x15
+SYM_FUNC_START(__arch_copy_from_user)
+	add	end, x0, x2
+	mov	srcin, x1
+#include "copy_template.S"
+	mov	x0, #0				// Nothing to copy
+	ret
+
+	// Exception fixups
+9997:	cmp	dst, dstin
+	b.ne	9998f
+	// Before being absolutely sure we couldn't copy anything, try harder
+USER(9998f, ldtrb tmp1w, [srcin])
+	strb	tmp1w, [dst], #1
+9998:	sub	x0, end, dst			// bytes not copied
+	ret
+SYM_FUNC_END(__arch_copy_from_user)
+EXPORT_SYMBOL(__arch_copy_from_user)