Kernel/Arch Build System
For quite some time, various methods have been proposed to easily build a custom kernel from the -ARCH one. All these were intelligent ideas, but suffered from some drawbacks and were not officially supported by the devs.
On the contrary, the method described in this article should be more solid and safe, and builds on the official Template:Package Official package.
To get the whole tree run:
See Arch Build System for more information.
Getting the Ingredients
First of all, you need a clean kernel to start your customization from. In this article I will assume that you use the official kernel package. So create a folder you want to work in and get the kernel package files from ABS (after syncing):
Then, get any other file you need (e.g. custom configuration files, patches, etc.) from the respective sources.
Modifying the PKGBUILD
Modify the PKGBUILD of the official linux package.
The first lines will look like this: Template:File
As you see, there is a commented line for building a kernel with a different name. All you need to do here is to uncomment that line, change the suffix '-custom' to your needs, and comment the standard line. For instance, your file could become: Template:File
Now, all the variables of your package will be changed according to the new name. For instance, after installing the package the modules will be located at Template:Filename.
You probably need a custom .config file for your kernel. You can uncomment one of the possibilities shown in the build() function of the PKGBUILD, e.g.: Template:File
If you have already a kernel config file, I suggest to uncomment one interactive config tool, such as nconfig, and load your config from there. This avoids problems with kernel naming I have met with other methods.
Changing the package_linux() function
Now, you have to write a custom function to tell your system how to install the package. This is most easily done by changing the name of the package_linux() function to package_linux-test(), and adapting the instructions to your needs. If you have no particular needs, your package_linux-test() should look like this: Template:File
You can now proceed to compile you kernel by the usual command Template:Codeline If you have chosen an inteactive program for configuring the kernel parameters (like menuconfig), you need to be there during the compilation.
After the 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 with pacman (or equivalent program):
# pacman -U <kernel_package>
Now, the folders and files for your custom kernel have been created, e.g. Template:Filename. To test your kernel, update your bootloader (/boot/grub/menu.lst for GRUB) and add new entries ('default' and 'fallback') for your custom kernel. That way, you can have both the stock kernel and the custom one in parallel.