Introduction
git
I’ll be using git to get the latest kernel version. This is my favorite
way to get the sources and it is in my opinion the fastest way to make
changes later on when you want to update your own kernel to the latest
version.
I suggest adding my Launchpad repository to your system.
The repository holds the latest version of git and is usually updated
within a day of a new release of git, follow the instructions on the
page
Git Packages for Ubuntu to add my repository. There is a version available for Ubuntu 10.10 as well.
Architecture
I am compiling the i386 version, if you want to compile for amd64 you need replace i386 for amd64 throughout this article.
Flavor
I choose the name core2 as the flavor name as for my personal use I’ll
build a kernel for a Core2 processor. Besides the change of processor
type in the configuration I also select support for 64GB as my laptop
has 4GB, which is the main reason I started compiling my own kernels. I
have some other changes but that’s beyond this article.
Preparations
Let’s get started by preparing our machine for compiling the Ubuntu Maverick kernel.
Open a terminal.
sudo su -
apt-get install fakeroot build-essential
apt-get install crash kexec-tools makedumpfile kernel-wedge
apt-get build-dep linux
apt-get install git-core libncurses5 libncurses5-dev
apt-get install libelf-dev libdw-dev asciidoc binutils-dev
exit
Create
a directory where you would like to build your kernel, this directory
will hold the kernel source in a sub directory and all the deb files
will end up in this folder. I choose /d1/development/kernel/maverick
Getting the source
cd /d1/development/kernel/maverick
git clone git://kernel.ubuntu.com/ubuntu/ubuntu-maverick.git source
cd source
The source code is installed in the directory source.
Creating a branch
We will create a branch in which we will be doing our modifications.
That way the master branch will stay in tact which will make it a whole
lot easier when we want to update our own Ubuntu 10.10 kernel to a newer
version.
To see all the available kernels available type the following command:
The Ubuntu kernel developers tag each version as Ubuntu- and therefore we can checkout the version we want as
git checkout Ubuntu-2.6.35-23.37 -b core2
This will create a branch called core2.
Creating a new config
I’ll
be using the method of creating a new flavor, this adds a bit more work
but this way you can always compile the original kernels.
We’ll use the generic flavor as the base for our own flavor being core2.
cp debian.master/config/i386/config.flavour.generic debian.master/config/i386/config.flavour.core2
fakeroot debian/rules clean
debian/rules updateconfigs
To
make changes to the configuration file we need to edit the
configuration file. The kernel developers have created a script to edit
kernel configurations which has to be called through the debian/rules
makefile, unfortunately you will have to go through all the flavors for
this script to work properly.
The
script will ask you if you want to edit the particular configuration.
You should not make changes to any of the configurations until you see
the core2 configuration
Do you want to edit config: i386/config.flavour.core2? [Y/n]
Make your changes, save the configuration and then keep going until the script ends.
When you’re done, make a backup of the config flavor file.
cp debian.master/config/i386/config.flavour.core2 ../.
Now we need to clean up the git tree in order to get ready for compilation.
git reset --hard
git clean -xdf
Getting ready for compilation
Because
we are going to be creating a new flavor based on a existing flavor
(generic in my case) we need to create some extra files. During
compilation the process checks the previous release for some settings,
as we’re creating a local flavor it doesn’t exist in the source, so
we’re creating it. The previous release in this case is 2.6.35-23.36
cp debian.master/abi/2.6.35-23.36/i386/generic debian.master/abi/2.6.35-23.36/i386/core2
cp debian.master/abi/2.6.35-23.36/i386/generic.modules debian.master/abi/2.6.35-23.36/i386/core2.modules
Copy our flavored configuration file back.
cp ../config.flavour.core2 debian.master/config/i386/
We need to edit some files:
File: debian.master/etc/getabis
Search for the line:
getall i386 generic generic-pae virtual
Change it in:
getall i386 generic generic-pae virtual core2
File: debian.master/rules.d/i386.mk
Search for the line:
flavours = generic generic-pae virtual
Change it in:
flavours = generic generic-pae virtual core2
We need to make the compilation process aware of our own flavor we want to compile.
cp debian.master/control.d/vars.generic debian.master/control.d/vars.core2
You can edit the file and make it your own.
arch="i386 amd64"
supported="Core2"
target="Geared toward Core2 desktop systems."
desc="x86/x86_64"
bootloader="grub-pc | grub | lilo (>= 19.1)"
provides="kvm-api-4, redhat-cluster-modules, ivtv-modules, ndiswrapper-modules-1.9"
We need to commit our changes in the git repository.
git add .
git commit -a -m "Core2 modifications"
The text after -m is the message you add to your commit.
Compilation
It’s
finally time for compiling but before we can start the compilation
process there is one more step to do. I didn’t put this in the
Preparations section as you need to the following step whether you make
changes to the configuration or not
fakeroot debian/rules clean
All the packages will be created in the directory /d1/development/kernel/maverick
Create independent packages:
skipabi=true skipmodule=true fakeroot debian/rules binary-indep
The above statement will create the following deb files:
linux-headers-2.6.35-23_2.6.35-23.37_all.deb
linux-tools-common_2.6.35-23.37_all.deb
linux-doc_2.6.35-23.37_all.deb
linux-source-2.6.35_2.6.35-23.37_all.deb
Create the tools package:
skipabi=true skipmodule=true fakeroot debian/rules binary-perarch
The above statement will create the following deb file:
linux-tools-2.6.35-23_2.6.35-23.37_i386.deb
Create the flavour depended files:
skipabi=true skipmodule=true fakeroot debian/rules binary-core2
The above statement will create the following deb files:
linux-headers-2.6.35-23-core2_2.6.35-23.37_i386.deb
linux-image-2.6.35-23-core2_2.6.35-23.37_i386.deb
Installation
After the compilation is finished we’ll have the above packages in the parent directory.
To install the files
cd ..
sudo dpkg -i linux-headers-2.6.35-23-core2_2.6.35-23.37_i386.deb linux-headers-2.6.35-23_2.6.35-23.37_all.deb linux-image-2.6.35-23-core2_2.6.35-23.37_i386.deb
Check
your bootloader if the newly installed kernel is the default one, for
grub check the file /boot/grub/menu.lst or if you run grub2 check
/boot/grub/grub.cfg
Reboot and enjoy your newly installed kernel.
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