How to build the Linux kernel for an x86_64 architecture

How to build the Linux kernel for an x86_64 architecture#

Get a Linux repository#

After successfully installing kw, it’s time to build the Linux kernel using it. Let’s start by cloning the Linux repository from Torvalds into our current working directory:

git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Then, change the current directory to the Linux repository:

cd linux

Note

From now on, all commands will assume you’re in the kernel folder.

Get .config#

To build the kernel, a .config file is necessary. This file contains configurations about the kernel compilation process. To retrieve this file from your computer, run either:

cp /boot/config-`uname -r` .config

Or:

zcat /proc/config.gz > .config

Note

Get the .config file from the same Linux distribution you plan on using the customized kernel in.

Change .config a bit#

A small modification you can make in the .config file is changing the kernel release name. To do that, run:

kw build --menu

Or its shorter form:

kw b -n

The default menu config option is set in the kworkflow.config file as nconfig, but it can be changed, for instance, to menuconfig, or whichever you prefer. To change this option, you can use:

kw config build.menu_config menuconfig

After running the command above, go to General setup, then Local version - append to kernel release, choose any name you like, save the new configuration and exit the menu.

Note

You can read more about the kworkflow.config file in our manual.

Build!#

Building the kernel now is as easy as invoking:

kw build

And it can be even simpler by just running:

kw b

Well, that’s it. kw will automatically infer the number of job slots for compiling based on the number of cores of your machine (i.e. when running make -j<number>, <number> is an integer that specifies the number of processes that will run at the same time), and compilation will begin!

Compiling patchsets#

You may want to try compiling every patch in your patchset to test if everything is alright. You can do this by using the “from-sha” flag:

kw build --from-sha SHA

This will compile every patch after the commit with given SHA to the branch HEAD.