3.3 KiB
ekernel - Custom Gentoo EFI Stub Kernel Updater
Automate custom gentoo kernel update tasks.
The update process can be divided into the following steps:
- configure - copy and update the previous
.config - build - compile the new kernel and install modules
- install - copy the new EFI stub kernel image to the EFI system partition
- commit - commit the new config with a detailed commit message
- clean - remove unused kernel source directories, modules and boot images
This tool aims to minimize the effort by automating the previous steps, while ensuring maximum flexibility w.r.t. configuration changes.
Tasks
The following variables will be used throughout this description:
old - previous kernel's source directory
new - new kernel's source directory
esp - directory containing the live kernel image on the EFI system partition (/boot/EFI/Gentoo/bootx64.efi)
jobs - number of parallel make jobs given by -j (default: 64)
version - new kernel's version string
ekernel-configure
Runs make menuconfig if the current config file is missing, or no other kernel is installed
Otherwise, copy the current config file to the new source directory if it doesn't exist (prevent accidental overwrite).
cp -n ${old}/.config ${new}
Get newly added config options and store the result in ${new}/.newoptions.
cd ${new}
make listnewconfig > ${new}/.newoptions
If -l was selected: print newly added config options and exit.
cat ${new}/.newoptions
exit
Interactively update the previous config and exit if aborted.
cd ${new}
make oldconfig || exit
ekernel-build
Build and install modules, using the given number of jobs.
make -j ${jobs} && make modules_install
ekernel-install
Update symlink /usr/src/linux to the new source directory.
eselect kernel set $(basename ${new})
Install the EFI stub kernel image (and a backup copy to revert to in case something breaks after a subsequent kernel update).
mount /boot
cp ${new}/arch/x86_64/boot/bzImage ${esp}/bootx64.efi
cp ${new}/arch/x86_64/boot/bzImage ${esp}/gentoo-${version}.efi
Rebuild external modules.
emerge @module-rebuild
ekernel-clean
Remove unused kernel source directories, modules and boot images.
emerge --depclean sys-kernel/gentoo-sources
rm -rf $(find /usr/src/ -maxdepth 1 -name "linux-*" | sed -e '/${old}/d' -e '/${new}/d')
rm -rf $(ls -1 /lib/modules/ | sed -e '/${old}/d' -e '/${new}/d')
rm -rf $(ls -1 ${esp} | sed -e '/${old}/d' -e '/${new}/d' -e '/bootx64/d')
The default is to keep the previous kernel version in case something goes horribly wrong.
ekernel-commit
Commit the new kernel config with a detailed commit message.
git add -f /usr/src/linux/.config
git commit -S -m "${msg}"
The message will not only contain the version change, but also details about the newly added or removed options.
Installation
You may use the ebuild app-admin/ekernel from my personal repository.