Kernel/Arch Build System
See Kernels for the main article.
The Arch Build System can be used to build a custom kernel based on the official linux package. This compilation method can automate the entire process, and is based on a very well tested package. You can edit the PKGBUILD to use a custom kernel configuration or add additional patches.
Contents
Getting the Ingredients
Since you'll be using makepkg, follow the best practices outlined there first. For example, you cannot run makepkg as root/sudo. Therefore, create a build
directory in your user home first.
$ cd ~/ $ mkdir build $ cd build/
Install the asp package and the base-devel package group.
You need a clean kernel to start your customization from. Fetch the latest kernel package files from ABS into your build directory by running:
$ asp update linux $ asp checkout linux
Then, get any other file you need (e.g. custom configuration files, patches, etc.) from the respective sources.
Modifying the PKGBUILD
Edit PKGBUILD
and look for the pkgbase
parameter. Change this to your custom package name, e.g.:
pkgbase=linux-custom
Depending on the PKGBUILD you may have to also rename linux.install
to match the modified pkgbase
.
Changing prepare()
In prepare function, you can apply needed kernel patch or change kernel build configuration.
If you need to change a few config options you can edit config file in the source.
Or you can use GUI tool to tweak the options. Comment make olddefconfig
in the prepare() function of the PKGBUILD, and add your favorite tool:
PKGBUILD
... msg2 "Setting config..." cp ../config .config #make olddefconfig make nconfig # new CLI menu for configuration #make menuconfig # CLI menu for configuration #make xconfig # X-based configuration #make oldconfig # using old config from previous kernel version # ... or manually edit .config ...
/usr/share/doc/systemd/README
. Check them before you compile.These requirements also change over time. Because Arch assumes you are using the official kernel, there will be no announcement of these changes. Before you install a new version of systemd, check the version release notes to make sure your current custom kernel meets any new systemd requirements.Generate new checksums
Install the pacman-contrib package.
As we modified config, we need to generate new checksums by running:
$ updpkgsums
Compiling
You can now proceed to compile your kernel by the usual command makepkg
If you have chosen an interactive program for configuring the kernel parameters (like menuconfig), you need to be there during the compilation.
$ makepkg -s
The -s
parameter will download any additional dependencies used by recent kernels such as xml and docs.
- Kernel sources are PGP signed, and makepkg will attempt to verify them. See Makepkg#Signature checking for details.
- Running compilation jobs simultaneously can reduce compilation time significantly on multi-core systems.
Installing
After running makepkg, you can have a look at the linux.install
file. You will see that some variables have changed.
Now, you only have to install the package as usual. Best practice is to install kernel headers first as they will be needed (e.g. to install the nvidia driver) for the custom kernel later.
# pacman -U kernel-headers_package # pacman -U kernel_package
Boot Loader
Now, the folders and files for your custom kernel have been created, e.g. /boot/vmlinuz-linux-test
. To test your kernel, update your bootloader configuration file and add new entries ('default' and 'fallback') for your custom kernel. If you renamed your kernel in the PKGBUILD pkgbase you may have to rename the initramfs.img in your $build/pkg/kernel/etc before installing with pacman. That way, you can have both the stock kernel and the custom one to choose from.
See Also
- https://kernel.org/doc/Documentation/kbuild/kconfig.txt and the parent directory