Prominent Intel Linux engineer H. Peter Anvin has posted a new patch series working to clean-up the Linux x86/x86_64 kernel boot code. Besides cleaning up the code, the kernel configuration would drop options around EFI stub mode and relocatable kernels in making those features now always enabled.

CONFIG_EFI_STUB is for allowing the compressed kernel executable to be loaded directly by the EFI firmware without the use of a bootloader. While many Linux users still rely on a bootloader like GRUB or systemd-boot, EFI_STUB doesn’t impact or restrict that ability. With EFI_STUB not affecting the run-time memory footprint and most Linux x86/x86_64 systems these days being EFI-based anyhow, H. Peter Anvin argues for it to being unconditionally enabled with getting rid of the Kconfig option.