Add transitional flag for enabling arm kernel signing

build_image

Index: build_image
diff --git a/build_image b/build_image
index c6fdac0e2b12296813f76c38f5b2f41b2571eb75..306de59b3a52c8f831aaaffa9726d1a5c59c0397 100755
--- a/build_image
+++ b/build_image
@@ -92,6 +92,10 @@ DEFINE_string boot_args "noinitrd" \
 DEFINE_string usb_disk /dev/sdb3 \
   "Path syslinux should use to do a usb boot. Default: /dev/sdb3"
 
+# TODO(clchiou): Remove this flag after arm verified boot is stable
+DEFINE_boolean crosbug12352_arm_kernel_signing ${FLAGS_FALSE} \
+  "Sign kernel partition for ARM images (temporary hack)."
+
 DEFINE_boolean enable_rootfs_verification ${FLAGS_TRUE} \
   "Default all bootloaders to use kernel-based root fs integrity checking."
 DEFINE_integer verity_error_behavior 3 \
@@ -282,6 +286,11 @@ case "${TC_ARCH}" in
     exit 1
 esac
 
+if [[ ${FLAGS_crosbug12352_arm_kernel_signing} -eq ${FLAGS_TRUE} ]]; then
+  crosbug12352_flag="--crosbug12352_arm_kernel_signing"
+else
+  crosbug12352_flag="--nocrosbug12352_arm_kernel_signing"
+fi
 if [[ ${FLAGS_enable_rootfs_verification} -eq ${FLAGS_TRUE} ]]; then
   enable_rootfs_verification_flag="--enable_rootfs_verification"
 fi
@@ -405,6 +414,7 @@ create_boot_desc() {
   --keys_dir="${DEVKEYSDIR}"
   --usb_disk="${FLAGS_usb_disk}"
   --nocleanup_dirs
+  ${crosbug12352_flag}
   ${enable_rootfs_verification_flag}
 EOF
 }
@@ -794,10 +804,14 @@ fi
 # Place flags before positional args
 ${SCRIPTS_DIR}/bin/cros_make_image_bootable "${OUTPUT_DIR}" \
                                             "${PRISTINE_IMAGE_NAME}" \
-                                            ${USE_DEV_KEYS}
-
-# FIXME: only signing things for x86 right now.
-if [[ "${ARCH}" = "x86" ]]; then
+                                            ${USE_DEV_KEYS} \
+                                            ${crosbug12352_flag}
+
+# FIXME Test x86 image, and test arm image if enabled;
+# should unconditionally test an image after crosbug12352 is fixed
+if [[ "${ARCH}" = "x86" ]] ||
+   [[ "${ARCH}" = "arm" &&
+      "${FLAGS_crosbug12352_arm_kernel_signing}" -eq "${FLAGS_TRUE}" ]]; then
   BOOT_FLAG=
   if [ "${FLAGS_dev_install}" -eq "${FLAGS_TRUE}" ] ||
      [ "${FLAGS_factory_install}" -eq "${FLAGS_TRUE}" ]; then
@@ -819,7 +833,8 @@ if [ "${FLAGS_withdev}" -eq "${FLAGS_TRUE}" ] ; then
 
   update_dev_packages ${DEVELOPER_IMAGE_NAME}
   ${SCRIPTS_DIR}/bin/cros_make_image_bootable "${OUTPUT_DIR}" \
-                                              "${DEVELOPER_IMAGE_NAME}"
+                                              "${DEVELOPER_IMAGE_NAME}" \
+                                              ${crosbug12352_flag}
 fi
 
 # Clean up temporary files.