Device Driver Writing Red Hat 8 & 9
 

Hi!
I am having trouble with the first stage of my mission.
I am trying to compile some code to make a beginners module.
When I compile it I get some errors.
1)
It doesn't know what KERN_INFO is
I looked at the /usr/include/linux/kernel.h and it only has 1 sysinfo struct in there.
I did a search on the kernel.h file and other ones I found had the #defines in them which is how I knew what to write. I added this line into my own source file which removed the error...
$define KERN_INFO "<6>"
2)
I now get a parse error before ';' in function 'init_module'

I got this off here: lwn.net/Articles/21817 (need to be logged in to see it I think)

I

#define MODULE
#include <linux/module.h>
#include <linux/kernel.h>

int init_module(void)
{
printk(KERN_INFO "Hello, world\n");
return 0;
}

void cleanup_module(void)
{
printk(KERN_INFO "Goodbye cruel world\n");
}

I am running Redhat 8.0 with 2.4.20-24 kernel & Redhat 9 2.4.20-8
I should mention I am only typing 'gcc driver.c' to compile it.
Has anyone tryed this before?

ok, I go
gcc -c driver.c #and it happily creates a driver.o file
I then go
insmod -f ./driver.o
I used -f to force load as I also get version errors (must be to do with using an updated kernel). ie
Warning: kernel-module version mismatch
./driver.o was compiled for kernel version 2.4.9-9
while this kernel is version 2.4.20-24.8

ok, I go
gcc -c driver.c #and it happily creates a driver.o file
I then go
insmod -f ./driver.o
I used -f to force load as I also get version errors (must be to do with using an updated kernel). ie
Warning: kernel-module version mismatch
./driver.o was compiled for kernel version 2.4.9-9
while this kernel is version 2.4.20-24.8