add arm64 support

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

arch/arm64/kernel/include/prctl.h

@@ -0,0 +1,17 @@
+/* prctl.h COPYRIGHT FUJITSU LIMITED 2017 */
+#ifndef __HEADER_ARM64_COMMON_PRCTL_H
+#define __HEADER_ARM64_COMMON_PRCTL_H
+
+/* arm64 Scalable Vector Extension controls */
+#define PR_SVE_SET_VL		48			/* set task vector length */
+#define PR_SVE_SET_VL_THREAD	(1 << 1)		/* set just this thread */
+#define PR_SVE_SET_VL_INHERIT	(1 << 2)		/* inherit across exec */
+#define PR_SVE_SET_VL_ONEXEC	(1 << 3)		/* defer effect until exec */
+
+#define PR_SVE_GET_VL		49			/* get task vector length */
+/* Decode helpers for the return value from PR_SVE_GET_VL: */
+#define PR_SVE_GET_VL_LEN(ret)	((ret) & 0x3fff)	/* vector length */
+#define PR_SVE_GET_VL_INHERIT	(PR_SVE_SET_VL_INHERIT << 16)
+/* For conveinence, PR_SVE_SET_VL returns the result in the same encoding */
+
+#endif /* !__HEADER_ARM64_COMMON_PRCTL_H */