Start adding arm 64bit support

config/arch.aarch64

@@ -0,0 +1,32 @@
+# determines TARGET_CPU, if not forced by user
+  if [ -z "$TARGET_CPU" ]; then
+    TARGET_CPU=generic
+  fi
+
+# TARGET_CPU:
+# cortex-a35 cortex-a53 cortex-a57 cortex-a72 exynos-m1
+# qdf24xx thunderx xgene1
+
+# TARGET_FPU:
+# This specifies what floating point hardware (or hardware emulation) is
+# available on the target. Permissible names are:
+# fpa fpe2 fpe3 maverick vfp vfpv3 vfpv3-fp16 vfpv3-d16 vfpv3-d16-fp16
+# vfpv3xd vfpv3xd-fp16 neon neon-fp16 vfpv4 vfpv4-d16 fpv4-sp-d16
+# neon-vfpv4.
+
+# determine architecture's family
+  case $TARGET_CPU in
+    *)
+      TARGET_SUBARCH=aarch64
+      TARGET_VARIANT=armv8-a
+      TARGET_CPU_FLAGS="+crc+crypto"
+      TARGET_EXTRA_FLAGS="-mcpu=$TARGET_CPU$TARGET_CPU_FLAGS"
+      TARGET_FPU=neon
+      SIMD_SUPPORT="yes"
+      ;;
+  esac
+
+# setup ARCH specific *FLAGS
+  TARGET_CFLAGS="-march=$TARGET_VARIANT $TARGET_EXTRA_FLAGS"
+  [ -n "$TARGET_FPU" ] && TARGET_CFLAGS="$TARGET_CFLAGS $TARGET_FPU_FLAGS"
+  TARGET_LDFLAGS="-march=$TARGET_VARIANT -mcpu=$TARGET_CPU$TARGET_CPU_FLAGS"

scripts/image

@@ -207,6 +207,8 @@ IMAGE_NAME="$DISTRONAME-$TARGET_VERSION"
     KERNEL_ARCH="x86"
   elif [ "$TARGET_ARCH" = arm ]; then
     KERNEL_ARCH="arm"
+  elif [ "$TARGET_ARCH" = aarch64 ]; then
+    KERNEL_ARCH="arm64"
   fi
 
   if [ "$BOOTLOADER" = "bcm2835-bootloader" ]; then