Add arm64 grub installation support

Add the necessary variables in grub.cfg and populate the EFI
partition with arm64 efi executable and modules.

Signed-off-by: Andrej Rosano <andrej@inversepath.com>

build_library/build_image_util.sh

@@ -361,7 +361,11 @@ finish_image() {
   # This script must mount the ESP partition differently, so run it after unmount
   if [[ "${install_grub}" -eq 1 ]]; then
     local target
-    for target in i386-pc x86_64-efi x86_64-xen; do
+    local target_list="i386-pc x86_64-efi x86_64-xen"
+    if [[ ${BOARD} == "arm64-usr" ]]; then
+      target_list="arm64-efi"
+    fi
+    for target in ${target_list}; do
       if [[ "${PROD_IMAGE}" -eq 1 && ${FLAGS_enable_verity} -eq ${FLAGS_TRUE} ]]; then
         ${BUILD_LIBRARY_DIR}/grub_install.sh \
             --target="${target}" --disk_image="${disk_img}" --verity

build_library/grub.cfg

@@ -53,7 +53,11 @@ if [ -z "$linux_console" ]; then
         terminal_input console serial_com0
         terminal_output console serial_com0
     elif [ "$grub_platform" = efi ]; then
-        set linux_console="console=ttyS0,115200n8 console=tty0"
+        if [ "$grub_cpu" = arm64 ]; then
+            set linux_console="console=ttyAMA0,115200n8"
+        else
+            set linux_console="console=ttyS0,115200n8 console=tty0"
+       fi
     elif [ "$grub_platform" = xen ]; then
         set linux_console="console=hvc0"
     fi
@@ -66,6 +70,11 @@ else
     set suf=""
 fi
 
+# Use standard linux command for arm64
+if [ "$grub_cpu" = arm64 ]; then
+    set suf=""
+fi
+
 menuentry "CoreOS default" --id=coreos {
     gptprio.next -d usr -u usr_uuid
     if [ "$usr_uuid" = "7130c94a-213a-4e5a-8e26-6cce9662f132" ]; then

build_library/grub_install.sh

@@ -49,6 +49,10 @@ case "${FLAGS_target}" in
     x86_64-xen)
         CORE_NAME="core.elf"
         ;;
+    arm64-efi)
+        CORE_MODULES+=( serial efi_gop )
+        CORE_NAME="core-arm64.efi"
+        ;;
     *)
         die_notrace "Unknown GRUB target ${FLAGS_target}"
         ;;
@@ -192,6 +196,13 @@ case "${FLAGS_target}" in
         sudo cp "${BUILD_LIBRARY_DIR}/menu.lst" \
             "${ESP_DIR}/boot/grub/menu.lst"
         ;;
+    arm64-efi)
+        info "Installing default arm64 UEFI bootloader."
+        sudo mkdir -p "${ESP_DIR}/EFI/boot"
+        #FIXME(andrejro): shim not ported to aarch64
+        sudo cp "${ESP_DIR}/${GRUB_DIR}/${CORE_NAME}" \
+            "${ESP_DIR}/EFI/boot/bootaa64.efi"
+        ;;
 esac
 
 cleanup