Linux Kernel Programming basis 



1.

distribution: debian-40r4a (kernel: 2.6.18) from debian.org,
kernel source: linux-2.6.26.3.tar.bz2 from kernel.org.


2.

place and extract the kernel source tree under user home directory,
follow the ../linux-2.6.26.3/README file in the kernel package.

$ cd ~
$ bzip2 -dc linux-2.6.26.3.tar.bz2 | tar xvf -
$ cd linux-2.6.26.3
$ make clean mrproper
$ cp /boot/config-$(uname -r) ./.config
$ make menuconfig
$ make
$ su -c 'make install'
$ su -c 'make modules_install'
$ su -c 'update-initramfs -c -k 2.6.26.3'
Password:
update-initramfs: Generating /boot/initrd.img-2.6.26.3
$


3.

add following five lines in /boot/grub/menu.lst:

title           Debian GNU/Linux, kernel 2.6.26.3
root            (hd0,0)
kernel          /boot/vmlinuz-2.6.26.3 root=/dev/sda1 ro
initrd          /boot/initrd.img-2.6.26.3
savedefault


4.

$ cat hello.c

#include <linux/init.h>
#include <linux/module.h>
MODULE_LICENSE("Dual BSD/GPL");

static int hello_init(void)
{
       printk(KERN_ALERT "Hello, world\n");
       return 0;
}

static void hello_exit(void)
{
       printk(KERN_ALERT "Goodbye, cruel world\n");
}

module_init(hello_init);
module_exit(hello_exit);


$ cat Makefile

# If KERNELRELEASE is defined, we've been invoked from the
# kernel build system and can use its language.

ifneq ($(KERNELRELEASE),)
       obj-m := hello.o

# Otherwise we were called directly from the command
# line; invoke the kernel build system.
else
       KERNELDIR ?= /lib/modules/$(shell uname -r)/build
       PWD := $(shell pwd)
default:
       $(MAKE) -C $(KERNELDIR) M=$(PWD) modules
endif


$ make

$ ls
hello.c   hello.mod.c  hello.o   modules.order
hello.ko  hello.mod.o  Makefile  Module.symvers

$ su -c ' insmod ./hello.ko'
Password:

$ su -c ' rmmod ./hello.ko'
Password:

$


--------------------------------------------------------------------------------
Note:

1. use the current kernel configuration as the basis for the new kernel 
   configuration. Most debian based distributions have the kernel configuration
   file in the /boot directory (eg: config-2.6.26-2-286). make a copy and place
   it at the kerel source directory (eg: ~/linux-2.6.26.3), rename as .config . 
   use the menuconfig to read and edit the new .config file, and just answer yes
   to save the automatically made changes. also can turn on or off other proper
   options in menuconfig.

2. "make install" will copy files including kernel image "vmlinuz-2.6.26.3" to
    /boot directory.

3. "make modules_install" will copy modules to /lib/modules/2.6.26.3.

4. troubleshoot: "SIOCSIFADDR: No such device" problem.

    This may be caused by needed module, for example, on my machine PCNET32 is
    not enabled by "make defconfig".

    $ grep PCNET32 .config
    # CONFIG_PCNET32 is not set
    $

    config CONFIG_PCNET32 to m (modular) or y (build-in) and rebuild the source.

5. the printk messages print on the console window of the linux on VMware side,
    they don't print on the putty window, the ssh client side.

6. the kernel compilation and booting process go smoothly on VMware workstation 
    version 6, but fail on version 5.


 - jhlicc@gmai1.c0m