qcom-minimal-image: empty /boot so the ESP can be mounted there#349
qcom-minimal-image: empty /boot so the ESP can be mounted there#349Ricardo Salveti (ricardosalveti) wants to merge 1 commit into
Conversation
| find ${IMAGE_ROOTFS}/boot -mindepth 1 -delete | ||
| fi | ||
| } | ||
| ROOTFS_POSTPROCESS_COMMAND += "${@bb.utils.contains('MACHINE_FEATURES', 'efi', 'clean_boot_mountpoint; ', '', d)}" |
There was a problem hiding this comment.
it should be COMBINED_FEATURES here, since you also need efi DISTRO_FEATURES to be enabled to ensure /boot is not needed, no?
There was a problem hiding this comment.
But this is for the distro itself (meta-qcom-distro), and efi is enabled by default already.
|
Doesn't systemd mount it at |
|
Although this solution works for our case, it generally doesn't work for those using other images. Perhaps it would be better to prevent the kernel and bootloader from being installed in /boot on EFI machines. |
Depends if they are empty directories or not, currently for qcom-distro builds it is mounted under /efi and qcom-distro-sota (ostree-based) it is mounted under /boot, this PR is to try to align on the behavior. |
The goal is just to fix for the qcom-distro default images, but yeah, ideally it should be fixed in OE-core but it is not trivial, as UKI gets decided at the image level at this point (and installing kernel under /boot makes sense when UKI is not used, for example). |
Dmitry Baryshkov (lumag)
left a comment
Dmitry Baryshkov (lumag)
left a comment
There was a problem hiding this comment.
My expectation is that ESP is mounted at /boot/efi, not just /boot.
From https://uapi-group.org/specifications/specs/discoverable_partitions_specification/: The ESP used for the current boot is automatically mounted to /boot/ or /efi/, unless a different partition is mounted there (possibly via /etc/fstab) or the mount point directory is non-empty on the root disk. If both ESP and XBOOTLDR exist, the /efi/ mount point shall be used for ESP. By default /boot is not empty, so it is mounted under /efi. And it is not mounted because the kernel is installed there (not the UKI). |
Interesting. So, e.g. Debian (and several other distros) don't follow it. Thanks for the note.
|
|
I checked, the generated image contains a proper ESP data under |
Most distros are probably mounting at a different location via fstab, probably decided before the discoverable spec, which we are using here. |
You mean the /boot folder in the rootfs? UKI shouldn't be there as it is created at the image level there. |
Yes, it's not our UKI, it's just UEFI Image / Image.gz |
On EFI machines the system boots from the ESP partition via UKIs, so the kernel and boot loader entries staged in /boot of the rootfs are never used. Worse, a non-empty /boot prevents systemd from mounting the ESP there at runtime. Empty /boot at rootfs postprocess time, keeping the directory itself as the mountpoint. Guard on the efi machine feature, matching the ESP image's own gating, since on non-EFI machines /boot may be the real boot path. This also aligns the regular images with the OTA-enabled ones, where meta-updater already splits the boot content out of the rootfs and ships an empty /boot. The cleanup is a no-op for the sota pipeline, which discards the rootfs /boot content on its own. Signed-off-by: Ricardo Salveti <ricardo.salveti@oss.qualcomm.com>
Yeah, it is basically ignored with our current setup, not only because we're creating our own esp partition, but because UKI is not properly integrated in oe-core yet. It is just using disk space at this point, and by removing the content systemd will automatically mount our esp partition in /boot (same as done with the sota variant). I agree the right solution is to fix oe-core itself, will try to investigate this issue later. |
Ricardo Salveti (ricardosalveti)
force-pushed
the
efi-boot
branch
from
744aff4 to
a22f895
Compare
| # empty mountpoint and systemd can mount the ESP there at runtime. | ||
| clean_boot_mountpoint() { | ||
| if [ -d ${IMAGE_ROOTFS}/boot ]; then | ||
| find ${IMAGE_ROOTFS}/boot -mindepth 1 -delete |
There was a problem hiding this comment.
Would it be easier to:
clean_boot_mountpoint() {
rm -rf "${IMAGE_ROOTFS}/boot"
mkdir "${IMAGE_ROOTFS}/boot"
}
5 participants
On EFI machines the system boots from the ESP partition via UKIs, so the kernel and boot loader entries staged in /boot of the rootfs are never used. Worse, a non-empty /boot prevents systemd from mounting the ESP there at runtime.
Empty /boot at rootfs postprocess time, keeping the directory itself as the mountpoint. Guard on the efi machine feature, matching the ESP image's own gating, since on non-EFI machines /boot may be the real boot path.
This also aligns the regular images with the OTA-enabled ones, where meta-updater already splits the boot content out of the rootfs and ships an empty /boot. The cleanup is a no-op for the sota pipeline, which discards the rootfs /boot content on its own.