Compiling a kernel

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This is an example how to compile a Linux kernel. It has been tested for SUSE Linux 11.1 and kernel 2.6.27, but should work same or similar for every combination.

Contents

Check prerequesites

yast -i gcc

Get the code

  • Download the kernel from ftp.kernel.org
wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.27.tar.bz2
  • unpack the kernel
bunzip2 linux-2.6.27.tar.bz2
  • unpack the kernel for the second time
tar xvf linux-2.6.27.tar

Build it

  • configure the kernel
cd linux-2.6.27
make oldconfig
  • answer some un-understandable questions

The sense of the step make oldconfig is to tell the kernel its configuration, e.g. which parts should be built as a module, which parts should not be built at all and the name of your special build. oldconfig takes over the settings from the running kernel that you can check with zcat /proc/config.gz if the switch EXTRACT-IKCONFIG is on. The settings for the new kernel are stored in the file .config. E.g. a line CONFIG_LOCALVERSION="-thorsten" in .config would tell kernel 2.6.27 to call himself 2.6.27-thorsten.

  • compile the kernel,
make -j4
Note
on a virtual machine with two virtual CPUs @ 2.4 GHz, this lasted 55 minutes.
  • compile the drivers
make -j4 modules

Install it

  • install the drivers
make modules_install
  • install the kernel
cp arch/x86_64/boot/bzImage /boot/vmlinuz-2.6.27

This will install the kernel for the x86_64 architecture.

  • prepare the initial ramdisk
cp System.map /boot
mkinitrd

This will build an initial ramdisk for all kernels contained in /boot.

  • add an entry to the bootloader. Let's take grub's /boot/grub/menu.lst:
title 2.6.27-selfcompiled
   root (hd0,0)
   kernel /boot/vmlinuz-2.6.27 root=/dev/sda1
   initrd /boot/initrd-2.6.27

See also