RHEL5 Kernel HOWTO

This HOWTO will show you how to get a RHEL5-based openvz-sources kernel running on a Funtoo Linux system. Several steps are required including downgrading sys-fs/udev, emerging gcc-4.1.2 (which is required for building RHEL5 sources), and building and configuring the kernel. These steps are appropriate for getting any RHEL5-based 2.6.18 kernels built and running under Funtoo, not just openvz-sources.

Steps

1. Downgrade udev to a version compatible with kernels previous than 2.6.27:

echo ">=sys-fs/udev-147" >> /etc/portage/package.mask
emerge -u udev

2. This will also require a downgrade of lvm2, if you are using it. Version 2.02.68 is a good one to use:

echo ">=sys-fs/lvm2-2.02.69 >> /etc/portage/package.mask
emerge -u lvm2

3. Mask any openvz-sources version equal or newer than 2.6.27:

echo ">=sys-kernel/openvz-sources-2.6.27" >> /etc/portage/package.mask

4. openvz-sources-2.6.18* needs gcc-4.1.*, so you must install it prior build your future downgraded kernel. If you have newer versions than gcc-4.1.* then you must install this one. Also check your CFLAGS if you are using gcc-4.3.* or later *AND* your make.conf CFLAGS has -march=native, due previous GCC versions doesn't allow it. Check [1] and put a correct -march directive or remove it in your CFLAGS ie:

Code: /etc/make.conf

CFLAGS="-mtune=generic -O2 -pipe"

emerge =sys-devel/gcc-4.1.2

That may take a while, take a cup of your favourite beverage and wait until it is finished.

[1] http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/i386-and-x86_002d64-Options.html#i386-and-x86_002d64-Options

5. Switch to gcc-4.1* on your system:

localhost ~ # gcc-config -l
 [1] x86_64-pc-linux-gnu-4.1.2
 [2] x86_64-pc-linux-gnu-4.4.3 *
localhost ~ # gcc-config 1
* Switching native-compiler to x86_64-pc-linux-gnu-4.1.2...
>>> Regenerating /etc/ld.so.cache...                                                                                                                                                                                                     [ok]

* If you intend to use the gcc from the new profile in an already
* running shell, please remember to do:

*   # source /etc/profile

localhost ~ # source /etc/profile
localhost ~ # gcc --version
gcc (GCC) 4.1.2 (Gentoo 4.1.2 p1.3)
gcc (GCC) 4.1.2 (Gentoo 4.1.2 p1.3)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

localhost ~ #

6. Rebuild your sources:

cd /usr/src/linux
make menuconfig
[do your work]
make
cp arch/x86/boot/bzImage /boot/linux-2.6.18-openvz-028.068.9

7. Update /etc/boot.conf to point to your new kernel, ie:

vi /etc/boot.conf
[inside /etc/boot.conf now]
"Funtoo Linux" {
        kernel linux-2.6.18-openvz-028.068.9
        params root=/dev/sda3
}

8. Update grub's configuration file

boot-update

9. Reboot your computer and enjoy

reboot