Kernel Compiling


Step # 1 Get Latest Linux kernel code

Visit http://kernel.org/ and download the latest source code. File name would be linux-x.y.z.tar.bz2, where x.y.z is actual version number. For example file inux-2.6.25.tar.bz2 represents 2.6.25 kernel version. Use wget command to download kernel source code:
$ cd /tmp
$ wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-x.y.z.tar.bz2

Note: Replace x.y.z with actual version number.

Step # 2 Extract tar (.tar.bz3) file

Type the following command:
# tar -xjvf linux-2.6.25.tar.bz2 -C /usr/src
# cd /usr/src

Step # 3 Configure kernel

Before you configure kernel make sure you have development tools (gcc compilers and related tools) are installed on your system. If gcc compiler and tools are not installed then use apt-get command under Debian Linux to install development tools.
# apt-get install gcc

Now you can start kernel configuration by typing any one of the command:

  • $ make menuconfig – Text based color menus, radiolists & dialogs. This option also useful on remote server if you wanna compile kernel remotely.
  • $ make xconfig – X windows (Qt) based configuration tool, works best under KDE desktop
  • $ make gconfig – X windows (Gtk) based configuration tool, works best under Gnome Dekstop.

For example make menuconfig command launches following screen:
$ make menuconfig

You have to select different options as per your need. Each configuration option has HELP button associated with it so select help button to get help.

Step # 4 Compile kernel

Start compiling to create a compressed kernel image, enter:
$ make
Start compiling to kernel modules:
$ make modules

Install kernel modules (become a root user, use su command):
$ su -
# make modules_install

Step # 5 Install kernel

So far we have compiled kernel and installed kernel modules. It is time to install kernel itself.
# make install

It will install three files into /boot directory as well as modification to your kernel grub configuration file:

  • System.map-2.6.25
  • config-2.6.25
  • vmlinuz-2.6.25

Step # 6: Create an initrd image

Type the following command at a shell prompt:
# cd /boot
# mkinitrd -o initrd.img-2.6.25 2.6.25

initrd images contains device driver which needed to load rest of the operating system later on. Not all computer requires initrd, but it is safe to create one.

Step # 7 Modify Grub configuration file – /boot/grub/menu.lst

Open file using vi:
# vi /boot/grub/menu.lst

title           Debian GNU/Linux, kernel 2.6.25 Default
root            (hd0,0)
kernel          /boot/vmlinuz root=/dev/hdb1 ro
initrd          /boot/initrd.img-2.6.25
savedefault
boot

Remember to setup correct root=/dev/hdXX device. Save and close the file. If you think editing and writing all lines by hand is too much for you, try out update-grub command to update the lines for each kernel in /boot/grub/menu.lst file. Just type the command:
# update-grub
Neat. Huh?

Step # 8 : Reboot computer and boot into your new kernel

Just issue reboot command:
# reboot

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4 Responses to “Kernel Compiling”

  1. Elvis Pratel January 31, 2010 at 7:12 pm #

    What is the purpose of kernel compiling? Is it for just getting the latest version?

  2. jameslee July 21, 2010 at 1:50 am #

    hai i m james RHCE student(studying now).i like to write driver programs in linux.what i have to do?
    please help me.
    thank u…

  3. PRADEEP KUMAR PANDIT October 6, 2010 at 6:08 pm #

    hi vishal
    i need u actualy muge tumhari tarh wordpress mai site banane hai apna naam ka tho kase banayege
    jab banata hu tho charges ka option aa ta hai tho age forward nahi hota give me some step wise procedure

    thankx

    • Vishal Vyas October 7, 2010 at 5:19 am #

      @PRADEEP KUMAR
      hello

      tumhe site ka kya name rakhna hai batado me banakar deahu.

      thnks,
      vishal

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