View source for Linux: Kernel development for x86 modules

== Overview ==
The purpose of this page is to give the user a minimum amount of information to meet the goal of making a simple change to the kernel, building and installing it.

== Obtaining the kernel sources ==
Original sources, changelog and deb files for desired kernel version can be found in [http://packages.ubuntu.com Ubuntu Packages] archive.

For example sources of kernel 3.16.0-38-generic compiled for Ubuntu 14.04 (Trusty Tahr) are placed here [http://packages.ubuntu.com/trusty/linux-image-3.16.0-38-generic linux-image-3.16.0-38-generic]
* linux_x.y.z.orig.tar.gz - mainline Linux x.y.z sources
* linux_x.y.z-xx.yy.diff - Ubuntu patch
* config-x.y.z-xx-generic - Ubuntu configuration file (can be found inside linux-image-x.y.z-xx-generic_xxx_amd64.deb)

If modifications provided by Compulab - use CompuLab's patch in addition to Ubuntu patch, use CompuLab's config file instead of Ubuntu's one
* compulab.x.y.z-module_name.diff - CompuLab patch for the module
* config-x.y.z-xx-compulab.module_name - CompuLab config file

== Development ==
* Use a 64-bit machine with Ubuntu, LinuxMint, or another compatible distribution as kernel building host workstation
* Install the programs and tools required for kernel building
<pre>
$ sudo apt-get install libncurses5 libncurses5-dev kernel-package build-essential
</pre>
* Prepare sources, apply patches and prepare initial config file
<pre>
$ cd /path/to/module_name/kernel
$ tar -xvzf linux_x.y.z.orig.tar.gz
$ cd linux-x.y.z
$ patch -p1 < ../patches/linux_x.y.z-xx.yy.diff
$ patch -p1 < ../patches/compulab.x.y.z-module_name.diff
$ cp ../config-x.y.z-xx-compulab.module_name .config
</pre>
* Make modifications for your needs and configure the new kernel
** (optional) change CONFIG_LOCALVERSION="-compulab.module_name" to "-yourname.module_name"
<pre>
$ make menuconfig
</pre>
* If you have a more than one processor or more than one core, you can speed things up by running concurrent compile commands. Setup CONCURRENCY_LEVEL=16 for 8 cores
<pre>
$ export CONCURRENCY_LEVEL=16
</pre>
* Compile the kernel and create the .deb packages
** (optional) revision=yyyy.mm.dd can be changed to another custom string, it will appear as part of the .deb file name
<pre>
$ fakeroot make-kpkg --initrd --revision=yyyy.mm.dd kernel_image kernel_headers
</pre>
* The linux-image-*.deb and linux-headers-*.deb packages will be created in the parent directory

== Installation ==
* Make the linux-*.deb files accessible from the module, for example mount them with NFS or attach a disk-on-key with the files
* Install new linux-*.deb packages:
<pre>
sudo dpkg -i /path/to/linux-*.deb
</pre>


[[Category:Linux |Kernel]]