A simple tourial for Linux 2.6.24 kernel module

Author: Charles Yang <chio.yang@gmail.com>

Linux Dist: Ubuntu 8.04 hard

1. Preparation

1.1 download source code with apporiate version

Usually, the Linux release distribution have no full kernel source code tree. So you shoshould get a copy of kernel source fromWww.kernel.org. For convience, you had better download the same version as you running Linux kernel.

You can typeUname-RIn you X-term, for example:

Charles @ Charles - Laptop ~ > Uname - R
2.6 . 24 - 16 - Generic

1.2 learn the document for Linux kernel module (lkm)

Once you plan to do modules development, you should refer:$ Srcdir/document/kbuild/modules.txt

In my Ubuntu 8.04, I can find it in // Usr/src/linux-headers-2.6.24-16/documentation/kbuild

Now let read the document for module development ..

1). How to Build external Module

From modules.txt, we know the simplest make command:

Make - C < Path - To - Kernel > M = 'Pwd'

The <path-to-kernel> means the kernel source path.

For the running kernel use:

Make - C / Lib / Modules / 'Uname - R' / Build m = 'Pwd'

The-C option: change to the directory before execute the make command.

actually, that will result in search the makefile in / lib / modules / 2.6 . 24 - 16 - generic / build in my OS.

notice: Most of files in / lib / modules / 2.6 . 24 - 16 - generic / build actually link to /usr/src/linux-headers-2.6.24-16/

The M = 'pwd': Define a macro required by makefile in/Lib/Modules/2.6.24-16-Generic/Build, which can tell the directory of current exernal module code.

Therefore youNeedn'tWrite your own makefile for build your modules, that's completedKbuild-A good machism for kernel modules.

2. Make target

Make - C $ kdir m = 'Pwd'
Make - C $ kdir m = 'Pwd' all
Make - C $ kdir m = 'Pwd' modules
Make - C $ kdir m = 'Pwd' modules_install
Make - C $ kdir m = 'Pwd' clean
Make - C $ kdir m = 'Pwd' help

The first 3 commands are absolutely same. For more details, you can referModules.txt