Removal of CONFIG_EFI_STUB ubuntu 24.04 breaks some use cases

[Magesh GV]

Hi,

We have been having a special use case where grub is used as stage 2 uboot. Then grub loads the linux kernel (in our case a menu with different iso images).

This used to work great from earlier than ubuntu 22.04. However, this is now broken with ubuntu 24.04.

Loading the kernel from grub fails with an error like CONFIG_EFI_STUB is not enabled.

Looking at the kernel config, 5.15.0-1053-raspi (22.04) has the CONFIG_EFI_ options enabled.

CONFIG_EFI_STUB=y
CONFIG_EFI=y
CONFIG_EFI_PARTITION=y
CONFIG_EFI_ESRT=y
CONFIG_EFI_VARS_PSTORE=m
# CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE is not set
CONFIG_EFI_PARAMS_FROM_FDT=y
CONFIG_EFI_RUNTIME_WRAPPERS=y
CONFIG_EFI_GENERIC_STUB=y
CONFIG_EFI_ARMSTUB_DTB_LOADER=y
CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER=y
CONFIG_EFI_BOOTLOADER_CONTROL=m
# CONFIG_EFI_CAPSULE_LOADER is not set
# CONFIG_EFI_TEST is not set
# CONFIG_EFI_DISABLE_PCI_DMA is not set
CONFIG_EFI_EARLYCON=y
CONFIG_EFIVAR_FS=m

In 6.8.0-1004-raspi, there is only:
# CONFIG_EFI is not set
CONFIG_EFI_PARTITION=y

Could you please enable back the CONFIG_EFI_ options back to raspi kernel. Even though raspi does not have UEFI, using a stage 2 bootloader like grub requires the EFI_STUB.

FYI, Looking at git history, these two commits removed most of CONFIG_EFI from the ubuntu raspi kernels.

commit 9f2edb8e5a7bfe2f72d63c0f04c7aa8f404d187e (tag: import/6.7.0-1001.1)
Author: Juerg Haefliger <email address hidden>
Date: Wed Jan 24 19:51:18 2024 +0100

    6.7.0-1001.1 (patches unapplied)

    Imported using git-ubuntu import.

commit 4dfdd5ed38710023544afd34ba882ec2048feafc (tag: import/6.5.0-1010.13)
Author: Juerg Haefliger <email address hidden>
Date: Thu Jan 18 08:48:24 2024 +0100

    6.5.0-1010.13 (patches unapplied)

    Imported using git-ubuntu import.

Side note: It would be great if linux-image-raspi is just merged to linux-image-generic. linux-firmware-raspi seems to be the really bootloader stuff that is independent of the kernel packages. So it should be safe to merge linux-image-raspi into linux-image-generic even for arm64.

Thanks.