Can't compile linux kernel module

[misplaced]

Hi.

I need to compile LKM (Ubuntu 8.04), but compiler have differ opinion:
source:

include <kernel.h>
include <module.h>

// end of file



$ gcc -g -D__KERNEL__ -DMODULE -O2 -I/usr/src/linux-headers-2.6.32-122/include -I/usr/src/linux-headers-2.6.32-122-rtai/include -I/usr/src/linux-headers-2.6.32-122/arch/x86/include -o ttt.o ttt.c
...

In file included from /usr/src/linux-headers-2.6.32-122/include/linux/prefetch.h:14,
from /usr/src/linux-headers-2.6.32-122/include/linux/list.h:6,
from /usr/src/linux-headers-2.6.32-122/include/linux/module.h:9,
from ttt.c:5:
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:116: error: ‘CONFIG_X86_L1_CACHE_SHIFT’ undeclared here (not in a function)
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:116: error: requested alignment is not a constant

...

/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h: In function ‘load_cr3’:
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:193: error: ‘CONFIG_PAGE_OFFSETUL’ undeclared (first use in this function)
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:193: error: (Each undeclared identifier is reported only once
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:193: error: for each function it appears in.)
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h: At top level:
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:242: error: requested alignment is not a constant
/usr/src/linux-headers-2.6.32-122/arch/x86/include/asm/processor.h:273: error: requested alignment is not a constant
...

What is CONFIG_X86_L1_CACHE_SHIFT and where it defined?

I read many examples of "Hello world" LKM. All of it begins with #include <linux/kernel.h> and <linux/module.h>. What i'm does wrong?

[dwhitney67]

Try using a Makefile to build a kernel module, not gcc.

This example Makefile may work for your needs:


obj-m := ttt.o

KDIR := /lib/modules/$(shell uname -r)/build

all:
$(MAKE) -C $(KDIR) M=$(PWD) modules

clean:
$(MAKE) -C $(KDIR) M=$(PWD) clean

Note that the Makefile above uses the system's running kernel version. If that differs from the version that you are targeting, then adjust the shell statement above.