Kernel hacking

Question

Hey guys,
I'm at a bit of a standstill here on a project I really don't feel like doing. I could ask this question in a more appropriate area, but I'd rather get a quicky from someone who knows me if that's possible...
The overall goal is to port a kernel module written for 2.4 a couple years ago to the 2.6 kernel. In order to test it, I wanted to get the original module working, so I've set up qemu with a warty ubuntu install that uses a 2.6 kernel by default; I installed a 2.4 kernel to work with. I tried compiling the module and got some errors described below, and I have tried writing a simple module as described here: http://bama.ua.edu/~dunna001/journeyman/html/c241.htm and got the same errors.
I'm pretty sure the errors are because the system is set up for a 2.6 kernel and either it is looking for the wrong include files or I have some other wrong headers or something. It is including the 2.4 source headers just fine, but those headers are trying to include stuff from /usr/include that are probably quite different for the 2.6 kernel.
Check out the errors:
gcc -Wall -O2 -I/home/user/linux-2.4.24/include -D__KERNEL__ -DMODULE -D__USER__ -c xyzzy.c -o xyzzy.o
In file included from /home/user/linux-2.4.24/include/linux/kernel.h:13,
from xyzzy.c:1:
/home/user/linux-2.4.24/include/linux/types.h:21: error: syntax error before "dev_t"
/home/user/linux-2.4.24/include/linux/types.h:21: warning: type defaults to `int' in declaration of `dev_t'
/home/user/linux-2.4.24/include/linux/types.h:21: warning: data definition has no type or storage class
In file included from /usr/include/asm/math_emu.h:4,
from /usr/include/asm/processor.h:11,
from /home/user/linux-2.4.24/include/linux/prefetch.h:13,
from /home/user/linux-2.4.24/include/linux/list.h:6,
from /home/user/linux-2.4.24/include/linux/module.h:12,
from xyzzy.c:2:
/usr/include/asm/sigcontext.h:79: error: syntax error before '*' token
/usr/include/asm/sigcontext.h:82: error: syntax error before '}' token
In file included from /usr/include/asm/processor.h:11,
from /home/user/linux-2.4.24/include/linux/prefetch.h:13,
from /home/user/linux-2.4.24/include/linux/list.h:6,
from /home/user/linux-2.4.24/include/linux/module.h:12,
from xyzzy.c:2:
/usr/include/asm/math_emu.h:6: error: syntax error before '*' token
/usr/include/asm/math_emu.h:7: error: syntax error before '*' token
In file included from /home/user/linux-2.4.24/include/linux/prefetch.h:13,
from /home/user/linux-2.4.24/include/linux/list.h:6,
from /home/user/linux-2.4.24/include/linux/module.h:12,
from xyzzy.c:2:
/usr/include/asm/processor.h:421: error: syntax error before '*' token
/usr/include/asm/processor.h:427: error: syntax error before '}' token
make: *** [xyzzy.o] Error 1
Any ideas how I can complie a 2.4 kernel module on a system that is currently running 2.4 but was originally compiled for 2.6?
Thanks,
Dusty

Answer 1

I'm using the sources, actually, rather than headers... turns out the problem was I needed to run make dep in the source directory first... its not working yet, but that particular error is solved.
Dusty