What is this?

A port of void linux' default efibootmgr hook to work with gentoo dist-kernel If you'd like to see more about their implimentation, please see void's efibootmgr package This implimentation supplants the requirement of a traditional bootloader. It will automatically add efibootmgr entries upon kernel installation/upgrade.

Why does this exist?

Primarily as a learning tool for myself. I actually use this setup on my personal machines. If you've stumbled across this, please ensure you know what these scripts are doing. Your mileage may vary. You have been warned.

How do I configure it?

Manually

Place the appropriate hooks from etc_hooks/ in /etc/kernel/ under their respective directories Place etc_hooks/default/efibootmgr-kernel-hook in the target device as /etc/default/efibootmgr-kernel-hook This will account for kernel version numbers present in /boot which are appended to the initrd and vmlinuz files by default both with genkernel and dracut Check the efibootmgr-kernel-hook file and place your own arguments inside, including UUID's and target device.

dracut vs genkernel

One important consideration is whether or not the target system will be utilizing dracut or genkernel. Both of these have different arguments required for LUKS to work.

dracut cmdline example

rd.luks.uuid=MY_ENCRYPTED_ROOT_UUID rd.luks.name=MY_ENCRYPTED_ROOT_UUID=crypt_root root=/dev/mapper/crypt_root

This would be placed in /etc/default/efibootmgr-kernel-hook in the OPTIONS variable for machines using dracut. Please read why you'd want both "rd.luks.uuid" and "rd.luks.name" present here

genkernel cmdline example

crypt_root=UUID=MY_ENCRYPTED_ROOT_UUID root=/dev/mapper/root

This would be placed in /etc/default/efibootmgr-kernel-hook in the OPTIONS variable for machines using genkernel.

Note: If you want to leverage genkernel's initramfs (which works better in my opinion), disable the initramfs use flag for gentoo-kernel and install genkernel.

After this, you can drop a 2 liner in /etc/kernel/postinst.d/ containing the following lines:

#!/bin/sh
genkernel initramfs --luks

This will cause gentoo-kernel to automatically leverage genkernel to produce the initramfs vice dracut.

inst.sh

This is a quick deployment script to be ran in a chroot. This was made to function inside of archiso (but can be used by any GNU/Linux system) with the following disk layout sdc2 being LUKS, with crypt_root being the name of it's unlocked part in /dev/mapper/

At the top of "inst.sh", simply plug in the target device (i.e /dev/sdc) and your desired InitramfsScheme (dracut or genkernel) and it will take care for the rest, including disabling the initramfs use flag for gentoo-kernel

sdc                                                               
├─sdc1         /mnt/boot               
├─sdc2                                 
│ └─crypt_root /mnt                    
└─sdc3                                 

Depencencies

gentoo-kernel (disable the initramfs use flag if you want to use genkernel instead), genkernel (optional, default is dracut) cryptsetup, efibootmgr, linux-firmware