How To Compile A Kernel - The SuSE Way

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Last edited 11/17/2006

Each distribution has some specific tools to build a custom kernel from the sources. This article is about compiling a kernel on SuSE systems. It describes how to build a custom kernel using the latest unmodified kernel sources from www.kernel.org (vanilla kernel) so that you are independent from the kernels supplied by your distribution. It also shows how to patch the kernel sources if you need features that are not in there.

I have tested this on SuSE 10.1.

I want to say first that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!

1 Preliminary Note

The goal of this tutorial is to build a kernel rpm package that can be installed on the system, and that you can share with others and install on other SuSE systems which is a big advantage compared to the "traditional" way where you don't end up with an rpm package.

2 Install Required Packages For Kernel Compilation

We must install ncurses-devel which is needed by the make menuconfig command which we run later on:

yast -i ncurses-devel

Next we must modify a few tools that are needed to build our kernel. If we don't modify them, we will get the following error message during the kernel build process:

/usr/lib/rpm/find-requires.ksyms: line 12: /usr/bin/nm: Argument list too long

and we won't be able to install our kernel rpm package.

Before we modify the tools, we create backup copies of them:

cp /usr/lib/rpm/find-provides.ksyms /usr/lib/rpm/find-provides.ksyms_orig
cp /usr/lib/rpm/find-requires.ksyms /usr/lib/rpm/find-requires.ksyms_orig
cp /usr/lib/rpm/find-supplements.ksyms /usr/lib/rpm/find-supplements.ksyms_orig

Then we open each of these scripts and replace kernel-*)           is_kernel_package=1 ;; with kernel*)           is_kernel_package=1 ;;:

vi /usr/lib/rpm/find-provides.ksyms

[...]
#kernel-*)           is_kernel_package=1 ;;
kernel*)           is_kernel_package=1 ;;
[...]

vi /usr/lib/rpm/find-requires.ksyms

[...]
#kernel-*)           is_kernel_package=1 ;;
kernel*)           is_kernel_package=1 ;;
[...]

vi /usr/lib/rpm/find-supplements.ksyms

[...]
#kernel-*)          is_kernel_package=1 ;;
kernel*)          is_kernel_package=1 ;;
[...]

3 Download The Kernel Sources

Next we download our desired kernel to /usr/src. Go to www.kernel.org and select the kernel you want to install, e.g. linux-2.6.18.2.tar.bz2 (you can find all 2.6 kernels here: http://www.kernel.org/pub/linux/kernel/v2.6/). Then you can download it to /usr/src like this:

cd /usr/src
wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.18.2.tar.bz2

Then we unpack the kernel sources and create a symlink linux to the kernel sources directory:

tar xjf linux-2.6.18.2.tar.bz2
ln -s linux-2.6.18.2 linux
cd /usr/src/linux

4 Apply Patches To The Kernel Sources (Optional)

Sometimes you need drivers for hardware that isn't supported by the new kernel by default, or you need support for virtualization techniques or some other bleeding-edge technology that hasn't made it to the kernel yet. In all these cases you have to patch the kernel sources (provided there is a patch available...).

Now let's assume you have downloaded the needed patch (I call it patch.bz2 in this example) to /usr/src. This is how you apply it to your kernel sources (you must still be in the /usr/src/linux directory):

bzip2 -dc /usr/src/patch.bz2 | patch -p1 --dry-run
bzip2 -dc /usr/src/patch.bz2 | patch -p1

The first command is just a test, it does nothing to your sources. If it doesn't show errors, you can run the second command which actually applies the patch. Don't do it if the first command shows errors!

If your patches are compressed with gzip (.gz) instead of bzip2 (.bz2), then you patch your kernel as follows:

gunzip -c /usr/src/patch.gz | patch -p1 --dry-run
gunzip -c /usr/src/patch.gz | patch -p1

You can also apply kernel prepatches to your kernel sources. For example, if you need a feature that is available only in kernel 2.6.19-rc6, but the full sources haven't been released yet for this kernel. Instead, a patch-2.6.19-rc6.bz2 is available. You can apply that patch to the 2.6.18 kernel sources, but not to kernel 2.6.18.1 or 2.6.18.2, etc. This is explained on http://kernel.org/patchtypes/pre.html:

Prepatches are the equivalent to alpha releases for Linux; they live in the testing directories in the archives. They should be applied using the patch(1) utility to the source code of the previous full release with a 3-part version number (for example, the 2.6.12-rc4 prepatch should be applied to the 2.6.11 kernel sources, not, for example, 2.6.11.10.)

So if you want to compile a 2.6.19-rc6 kernel, you must download the 2.6.18 kernel sources (http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.18.tar.bz2) in step 3 instead of kernel 2.6.18.2!

This is how you apply the 2.6.19-rc6 patch to kernel 2.6.18:

cd /usr/src
wget http://www.kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.19-rc6.bz2
cd /usr/src/linux
bzip2 -dc /usr/src/patch-2.6.19-rc6.bz2 | patch -p1 --dry-run
bzip2 -dc /usr/src/patch-2.6.19-rc6.bz2 | patch -p1