add arm64 support

- add arm64 dependent codes with GICv3 and SVE support
- fix bugs based on architecture separation requests

arch/arm64/kernel/include/mmu_context.h

@@ -0,0 +1,22 @@
+/* mmu_context.h COPYRIGHT FUJITSU LIMITED 2015 */
+#ifndef __HEADER_ARM64_COMMON_MMU_CONTEXT_H
+#define __HEADER_ARM64_COMMON_MMU_CONTEXT_H
+
+#include <pgtable.h>
+#include <memory.h>
+
+/*
+ * Set TTBR0 to empty_zero_page. No translations will be possible via TTBR0.
+ */
+static inline void cpu_set_reserved_ttbr0(void)
+{
+	unsigned long ttbr = virt_to_phys(empty_zero_page);
+
+	asm(
+	"	msr	ttbr0_el1, %0			// set TTBR0\n"
+	"	isb"
+	:
+	: "r" (ttbr));
+}
+
+#endif /* !__HEADER_ARM64_COMMON_MMU_CONTEXT_H */