@@ -2,6 +2,7 @@ subdir-$(arm32) += arm32
 subdir-$(arm64) += arm64
 subdir-y += platforms
 subdir-$(arm64) += efi
+subdir-$(HAS_ACPI) += acpi
 
 obj-$(EARLY_PRINTK) += early_printk.o
 obj-y += cpu.o

@@ -0,0 +1 @@
+obj-y += lib.o

@@ -0,0 +1,33 @@
+/*
+ *  lib.c - Architecture-Specific Low-Level ACPI Support
+ *
+ *  Copyright (C) 2015, Shannon Zhao <shannon.zhao@linaro.org>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  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, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <xen/acpi.h>
+#include <xen/mm.h>
+#include <asm/mm.h>
+
+void __iomem *
+arch_acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
+{
+    return __va(phys);
+}