Posted by gnurbs on Wed 22 Jul 2009 at 23:27
This article shows how to rebuild only a single module that comes with the main kernel tree for folks that neither need nor want to rebuild the whole kernel. If you want to build an out-of-tree module, than that module's documentation is probably the best starting point.
To make the intention of this howto somewhat clearer, this is the Problem I had: I have an old box i use for server-purposes and want to extend its functionality to an access-point. It has an ath5k-driven card, and for my running kernel (2.6.29-2-686 debian sid build) ath5k needs to be patched to enable master mode. Since the box is somewhat slow, I did not want to rebuild the kernel, plus that would force me to restart and losing uptime ;)
OK here we go:
apt-get install linux-headers-`uname-r` linux-source-$YourKernelsVersion
cd /usr/src
tar xjf linux-source-$Version.tar.bz2
kernels Makefile has a target M=$DIR you can use to build single modules. However, running this in /usr/src/linux-source-$Version fails, at least on my box, since I had not used it to actually build a kernel. Header files of a complete Build are missing, I understand. For this reason, we use linux-headers-`uname -r`-directory. However, this directory does not contain everything we need, most of the header files reside in linux-headers-$Version-common dir. I simply copied its contents into linux-headers-`uname -r`. There are propably more elegant ways...
cd linux-headers-`uname -r`
cp -rf ../linux-headers-$Version-common/* .
Figure out what directory your wanted module resides in. For me this is drivers/net/wireless/ath5k
cd linux-headers-`uname -r`
mkdir -p Path/To/Module
cp -rf ../linux-source-$Version/Path/To/Module/* Path/To/Module
make -M=Path/To/Module
You propably know how to go on yourself, but for completeness sake:
Now you have compiled the module, check it runs properly.
You may have to rmmod earlier versions of the module.
insmod Path/To/Module/Module.ko
If it works properly, its time to install it to your system:
cd /lib/modules/`uname -r`
mkdir -p Path/To/Module
if there is another build of the module you just compiled, you may want to do a backup:
mv Path/To/Module/Module.ko Path/To/Module/Module.ko.bak
cp /usr/src/linux-headers-`uname -r`/Path/To/Module/Module.ko Path/To/Module
depmod -a
Congratulations! If you made it this way, you finished. For me, it's now time to setup hostap...
This article can be found online at the Debian Administration website at the following bookmarkable URL (along with associated comments):
This article is copyright 2009 gnurbs - please ask for permission to republish or translate.