Tuesday, April 04, 2006

How to Compile Linux 2.6 Kernel

How To Compile Linux 2.6 Kernel on redhat 9/8

STEP 1:

Download the latest version of the kernel and any patches.
This documentation is done with linux-2.6.3, but look for
later versions.
Read More

http://www.kernel.org/pub/linux/kernel/v2.6/

Also take a look at
http://www.codemonkey.org.uk/post-halloween-2.5.txt This has
some useful hints on some of the changes needed.



STEP 2:

Download the latest version of module-init-tools
"module-init-tools-3.0.tar.gz" and
"modutils-2.4.21-23.src.rpm"

http://www.kernel.org/pub/linux/kernel/people/rusty/modules/module-init-tools-3.0.tar.gz
http://www.kernel.org/pub/linux/kernel/people/rusty/modules/modutils-2.4.21-23.src.rpm



STEP 3:

Install module-init-tools. This will replace depmod
[/sbin/depmod] and other tools.

tar -zxvf module-init-tools-3.0.tar.gz
cd module-init-tools-3.0
./configure --prefix=/sbin
make
make install
./generate-modprobe.conf /etc/modprobe.conf



STEP 4:

Install modutils-2.4.21-23.src.rpm. You may get warnings
about user rusty and group rusty not existing. Also, yes,
you'll have to force the install. If you don't do these steps
for both Redhat 9 and Redhat 8, you'll have problems with the
make modules_install.

rpm -i modutils-2.4.21-23.src.rpm
rpmbuild -bb /usr/src/redhat/SPECS/modutils.spec
rpm -Fi /usr/src/redhat/RPMS/i386/modutils-2.4.21-23.i386.rpm



STEP 5:

Install and configure the kernel. Do NOT use the /usr/src/linux
area! Reference the README. I put my files in /home/src/kernel/

gunzip linux-2.6.3.tar.gz tar -xvf linux-2.6.3.tar cd
linux-2.6.3

If you have patches install these now:

bzip2 -dc ../patch-2.6.xx.bz2 | patch -p1



STEP 6:

Copy the appropriate /usr/src/linux-2.4/configs
[kernel-2.4.20-i686.config, kernel-2.4.20-i686-smp.config]
to .config in whatever directory you are installing. In my
case it's /home/src/kernel/linux-2.6.3

cp /usr/src/linux-2.4/configs/kernel-2.4.20-i686.config /home/src/kernel/linux-2.6.3/.config

If you don't have the source configs, you can download them
from here:

https://sourceforge.net/project/showfiles.php?group_id=79320&package_id=109944

I've also included a file config2.6-chirico which was a 2.6
version for some of my systems. This isn't a bad reference if
you run into trouble.



STEP 7:

Assuming you copied the appropriate kernel-2.4 config to
.config, run the following which will run through necessary
questions for the 2.6 kernel. Or, you might want to use the
config2.6-chirico...this has already been run through make
oldconfig on my system, and I've answered the necessary questions
for a general system.

make oldconfig



STEP 8:

This is very important. Make sure you're .config has the
following in it CONFIG_EXT3_FS=y You'll run into the following
error if you leave this =m instead of =y:

pivotroot: pivot_root(/sysroot,/sysroot/initrd) failed

This is because Redhat 9.0 and 8.0 use the ext3 filesystem
for /boot ...



STEP 9:

Edit the Makefile and add changes to the Extraversion is needed.
Patches will update these values as well.

VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 3
EXTRAVERSION = -skim-ch6



STEP 10:

make bzImage



STEP 11:

make modules



STEP 12:

make modules_install



STEP 13:

make install

If you come across errors here, what version of "depmod" is
being picked up in your path?

Also, if you get a module not found, say the following:
No module aic7xxx found for kernel 2.6.x
Then, in /lib/modules/2.6.x/kernel/drivers/scsi/aic7xxx/
cp aic7xxx.ko aic7xxx.o

insmod should look for aic7xxx.ko ;but , it looks for aic7xxx.o

If you still have trouble, make the following change in the
.config
CONFIG_BLK_DEV_SD=y
and go back to STEP 10.

You also may want to ref
kernel-2.6.3-i686-smp-chirico-aic7xxx.config
in
http://prdownloads.sourceforge.net/souptonuts/configs-0.3.tar.gz?download



STEP 14:

mkdir /sys



STEP 15:

/etc/rc.sysinit needs to be modified. Look for the following
line:

action $"Mounting proc filesystem: " mount -n -t proc /proc /proc

and after this line enter the following:

action $"Mounting sysfs filesystem: " mount -t sysfs none /sys

Here's my /etc/rc.sysinit for reference:

http://prdownloads.sourceforge.net/souptonuts/rc.sysinit.txt?download



Be very careful at this step. Backup the /etc/rc.sysinit file.

Thomer [http://thomer.com/linux/migrate-to-2.6.html ] also added
changes to /etc/fstab. I only had to do STEP 16 below.



STEP 16:

Add the following to /etc/fstab for usb support.

/proc/bus/usb /proc/bus/usb usbdevfs defaults 0 0



STEP 17 (CHECKING EVERYTHING):

Check the following:

a. The new image file should be installed on boot and there
should be sym link to it. My latest kernel is 2.6.3-skim-ch6,
and I got the "-skim-ch6" from the values I put in the Makefile,
so I see the following:

/boot
vmlinuz -> vmlinuz-2.6.3-skim-ch6
System.map -> System.map-2.6.3-skim-ch6

/boot/grub/grub.conf Should have been automatically
updated from make.

In /boot/grub/grub.conf change "default=0" to boot
with the new kernel. Here's an example of my
grub.conf:


# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to
# root (hd0,2)
# kernel /vmlinuz-version ro root=/dev/hda6
# initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=10
splashimage=(hd0,2)/grub/splash.xpm.gz
title Red Hat Linux (2.6.3-skim-ch6)
root (hd0,2)
kernel /vmlinuz-2.6.3-skim-ch6 ro root=LABEL=/
initrd /initrd-2.6.3-skim-ch6.img


b. The directory /sys exists

c. You added the mount command for sys in /etc/rc.sysinit

d. CONFIG_EXT3_FS=y was used in the .config

e. Run /sbin/lsmod or cat /proc/modules to make
sure a 2.4 kernel module wasn't forgotten. Also
look at "$cat /proc/iomem"



STEP 18 (DEVELOP YOUR OWN 2.6 MODULES):

You're done with the 2.6 build. So learn how to develop
2.6 kernel modules. First, checkout the following article

http://lwn.net/Articles/driver-porting/

Then, take a look at the following sample code, which shows how
to create /proc entries for communicating with the kernel and writing
out to any available tty device.

http://prdownloads.sourceforge.net/souptonuts/procreadwrite.0.0.1a.tar.gz?download




REFERENCES:

http://www.codemonkey.org.uk/post-halloween-2.5.txt
http://kerneltrap.org/node/view/799
http://thomer.com/linux/migrate-to-2.6.html
http://www.kernel.org/

http://bugzilla.kernel.org/
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&group=linux.kernel
http://linuxdevices.com/articles/AT3855888078.html

http://prdownloads.sourceforge.net/souptonuts/README_26.txt?download
http://prdownloads.sourceforge.net/souptonuts/rc.sysinit.txt?download
http://prdownloads.sourceforge.net/souptonuts/configs-0.3.tar.gz?download
https://sourceforge.net/forum/forum.php?forum_id=353715

http://www.redhat.com/software/rhel/kernel26/
http://www.tldp.org/HOWTO/KernelAnalysis-HOWTO.html
http://www-124.ibm.com/linux/projects/?topic_id=2

KERNEL DRIVER DEVELOPMENT IN 2.6:

Excellent (series of articles):
http://lwn.net/Articles/driver-porting/

Here's my sample program:
http://prdownloads.sourceforge.net/cpearls/procreadwrite.0.0.1a.tar.gz?download

Good but dated for 2.4 kernel:
http://www.oreilly.com/catalog/linuxdrive2/

http://linuxdevices.com/articles/AT4389927951.html
http://linuxdevices.com/articles/AT5793467888.html

How to Compile 2.6 kernel for RedHat 9/8

How to Compile 2.6 kernel for RedHat 9/8
Mike Chirico
Last Updated: Wed Mar 24 09:12:06 EST 2004

The latest version of this document can be found at:
http://prdownloads.sourceforge.net/souptonuts/README_26.txt?download

For configs ref:
http://sourceforge.net/project/showfiles.php?group_id=79320&package_id=109944

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