OCPBUGS-54594: update bootloader on aarch64 systems

The aarch64 kernel changed the file format [1] [2] and older
RHEL8 based systems (4.12 and 4.11) need to update the bootloader
otherwise the system won't boot when they get upgraded to 4.19
based on RHEL 9.6.

Let's add a systemd unit here that will update the bootloader.
Also need to add code that will handle the RAID case because
bootupd doesn't currently handle that case.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2162369
[2] https://issues.redhat.com/browse/RHEL-25537

Fixes: https://issues.redhat.com/browse/OCPBUGS-54594

Author: dustymabe

overlay.d/05rhcos/usr/lib/systemd/system-preset/43-manifest-rhcos.preset

@@ -22,3 +22,8 @@ enable nmstate.service
 # This unit is not activated on OSTree systems, but it still pulls in
 # `network-online.target`. Explicitly disable it.
 disable dnf-makecache.timer
+
+# Enable the unit to update the bootloader on aarch64
+# machines so they can boot 9.6+ kernels.
+# https://issues.redhat.com/browse/OCPBUGS-54594
+enable coreos-bootupctl-update-aarch64.service

overlay.d/05rhcos/usr/lib/systemd/system/coreos-bootupctl-update-aarch64.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=Update Bootloader for aarch64 systems
+Documentation=https://issues.redhat.com/browse/OCPBUGS-54594
+ConditionArchitecture=arm64
+ConditionFirmware=uefi
+ConditionPathExists=!/var/lib/coreos-update-bootloader-aarch64-OCPBUGS-54594.stamp
+
+[Service]
+Type=oneshot
+# Only run once regardless of success or failure so we touch
+# our stamp file here.
+ExecStartPre=touch /var/lib/coreos-update-bootloader-aarch64-OCPBUGS-54594.stamp
+ExecStart=/usr/libexec/coreos-update-bootloader
+RemainAfterExit=yes
+MountFlags=slave
+
+[Install]
+WantedBy=multi-user.target

overlay.d/05rhcos/usr/libexec/coreos-update-bootloader

@@ -0,0 +1,49 @@
+#!/bin/bash
+set -euo pipefail
+
+# https://issues.redhat.com/browse/OCPBUGS-54594
+
+# This script updates the bootloader using bootupd
+# and also detects RAID-1 setups as those requires
+# extra steps.
+if [ -e /dev/disk/by-label/EFI-SYSTEM ]; then
+    echo "Found ESP; calling 'bootupctl update'"
+    bootupctl update
+    exit
+fi
+
+# Handle RAID case manually since bootupd doesn't support it.
+# https://github.com/coreos/bootupd/issues/132
+#
+# First we'll find the RAID device the root filesystem is
+# mounted from (i.e. /dev/md127).
+root_raid_device=$(findmnt --json --target /sysroot \
+                     | jq -r .filesystems[0].source)
+echo "Detected root raid device is: $root_raid_device"
+# Next we'll find all the devices that are a part of that
+# RAID array that have an ESP (i.e. a vfat formatted partition
+# with a label that starts with "esp-", like "esp-1", "esp-2").
+# and we'll capture the device name for the partition.
+esp_partitions=$(
+    lsblk --paths --fs -J | \
+        jq --arg raid_device "${root_raid_device}" -r '
+            .blockdevices[]
+            | select(.children[]?.children[]?.name == $raid_device)
+            | .children[]
+            | select(
+                (.fstype == "vfat") and
+                (.label != null)    and
+                (.label | startswith("esp"))
+              )
+            | .name')
+for part in $esp_partitions; do
+    echo "Found ESP replica in ${part}; updating"
+    mount $part /boot/efi
+    echo "[Before Update: ${part}]"
+    find /boot/efi/ -type f | xargs md5sum
+    cp -rp /usr/lib/bootupd/updates/EFI /boot/efi
+    echo "[After Update: ${part}]"
+    find /boot/efi/ -type f | xargs md5sum
+    umount /boot/efi
+done
+sync