No more boot loader: please use the kernel instead

Most people are familiar with GRUB, a powerful, flexible, fully-featured bootloader that is used on multiple architectures (x86_64, aarch64, ppc64le OpenFirmware). Although GRUB is quite versatile and capable, its features create complexity that is difficult to maintain, and that both duplicate and lag behind the Linux kernel while also creating numerous security holes. On the other hand, the Linux kernel, which has a large developer base, benefits from fast feature development, quick responses to vulnerabilities and greater overall scrutiny.

We (Red Hat boot loader engineering) will present our solution to this problem, which is to use the Linux kernel as its own bootloader. Loaded by the EFI stub on UEFI, and packed into a unified kernel image (UKI), the kernel, initramfs, and kernel command line, contain everything they need to reach the final boot target. All necessary drivers, filesystem support, and networking are already built in and code duplication is avoided.

↫ Marta Lewandowska

I’m not a fan of GRUB. It’s too much of a single point of failure, and since I’m not going to be dual-booting anything anyway I’d much rather use something that isn’t as complex as GRUB. Systemd-boot is an option, but switching over from GRUB to systemd-boot, while possible on my distribution of choice, Fedora, is not officially supported and there’s no guarantee it will keep working from one release to the next.

The proposed solution here seems like another option, and it may even be a better option – I’ll leave that to the experts to discuss. It seems like to me that the ideal we should be striving for is to have booting the operating system become the sole responsibility of the EUFI firmware, which usually already contains the ability to load any operating system that supports UEFI without explicitly installing a bootloader. It’d be great if you could set your UEFI firmware to just always load its boot menu, instead of hiding it behind a function key or whatever.

We made UEFI more capable to address the various problems and limitations inherent in BIOS. Why are we still forcing UEFI to pretend it still has the same limitations?

15 Comments

  1. 2024-07-09 6:29 pm
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