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7. Configuring the Kernel
You first need to select your timezone so that your system knows where it is
located. Look for your timezone in /usr/share/zoneinfo, then copy
it to /etc/localtime. Please avoid the
/usr/share/zoneinfo/Etc/GMT* timezones as their names do not
indicate the expected zones. For instance, GMT-8 is in fact GMT+8.
Code Listing 1.1: Setting the timezone information
# ls /usr/share/zoneinfo
# cp /usr/share/zoneinfo/GMT /etc/localtime
7.b. Installing the Sources
Choosing a Kernel
The core around which all distributions are built is the Linux kernel.
It is the layer between the user programs and your system hardware.
Gentoo provides its users several possible kernel sources. A full
listing with description is available at the Gentoo Kernel Guide.
For PPC64 you should use gentoo-sources. So let's continue with
emerge'ing the kernel sources. The USE="-doc" is necessary to
avoid installing xorg-x11 or other dependencies at this point.
USE="symlink" is not necessary for a new install, but ensures proper
creation of the /usr/src/linux symlink.
Code Listing 2.1: Installing a kernel source
# USE="-doc symlink" emerge gentoo-sources
When you take a look in /usr/src you should see a symlink called
linux pointing to your kernel source. In this case, the installed
kernel source points to gentoo-sources-2.6.12-r10. Your version may be
different, so keep this in mind.
Code Listing 2.2: Viewing the kernel source symlink
# ls -l /usr/src/linux
lrwxrwxrwx 1 root root 12 Oct 13 11:04 /usr/src/linux -> linux-2.6.12-gentoo-r10
Now it is time to configure and compile your kernel source. There is the
ability to use "genkernel" which would create a generic kernel like the
ones used on the installation CDs, but it is not fully functional for PPC64 at
Continue now with Manual Configuration.
7.c. Manual Configuration
Manually configuring a kernel is often seen as the most difficult procedure a
Linux user ever has to perform. Nothing is less true -- after configuring a
couple of kernels you don't even remember that it was difficult ;)
However, one thing is true: you must know your system when you
configuring a kernel manually. Most information can be gathered by emerging
pciutils (emerge pciutils) which contains lspci. You will now
be able to use lspci within the chrooted environment. You may safely
ignore any pcilib warnings (like pcilib: cannot open
/sys/bus/pci/devices) that lspci throws out. Alternatively, you can run
lspci from a non-chrooted environment. The results are the same.
You can also run lsmod to see what kernel modules the Installation CD
uses (it might provide you with a nice hint on what to enable).
Now go to your kernel source directory and execute make
menuconfig. This will fire up an ncurses-based configuration menu.
When compiling the kernel on a 32bit userland system add the following to
the bottom of /etc/profile:
Code Listing 3.1: 32bit userland make alias
# echo 'alias ppc64make="make ARCH=ppc64 CROSS_COMPILE=powerpc64-unknown-linux-gnu-"' >> /etc/profile
# source /etc/profile
Code Listing 3.2: Invoking menuconfig
# cd /usr/src/linux
(64bit userland) # make menuconfig
(32bit userland) # ppc64make menuconfig
You will be greeted with several configuration sections. We'll first
list some options you must activate (otherwise Gentoo will not function,
or not function properly without additional tweaks).
Activating Required Options
First of all, activate the use of development and experimental
code/drivers. You need this, otherwise some very important code/drivers
won't show up:
Code Listing 3.3: Selecting experimental code/drivers, General setup
Code maturity level options --->
[*] Prompt for development and/or incomplete code/drivers
General setup --->
[*] Support for hot-pluggable devices
Now go to File Systems and select support for the filesystems you
use. Don't compile them as modules, otherwise your Gentoo system
will not be able to mount your partitions. Also select Virtual
memory, /proc file system, and /dev/pts file system for
Code Listing 3.4: Selecting necessary file systems
File systems --->
[*] Virtual memory file system support (former shm fs)
[*] /proc file system support
[*] /dev/pts file system for Unix98 PTYs
<*> Reiserfs support
<*> Ext3 journalling file system support
<*> JFS filesystem support
<*> Second extended fs support
<*> XFS filesystem support
You will find some of the mentioned options under Pseudo
filesystems which is a subpart of File systems.
If you are using PPPoE to connect to the Internet or you are using a
dial-up modem, you will need the following options in the kernel (you
will find the mentioned options under Networking support which is
a subpart of Device Drivers):
Code Listing 3.5: Selecting PPPoE necessary drivers
Network device support --->
<*> PPP (point-to-point protocol) support
<*> PPP support for async serial ports
<*> PPP support for sync tty ports
The two compression options won't harm but are not definitely needed, neither
does the PPP over Ethernet option, that might only be used by
rp-pppoe when configured to do kernel mode PPPoE.
If you require it, don't forget to include support in the kernel for your
Disable ADB raw keycodes:
Code Listing 3.6: Disabling ADB raw keycodes
Macintosh Device Drivers --->
[ ] Support for ADB raw keycodes
When you're done configuring your kernel, continue with Compiling and Installing.
Compiling and Installing
Now that your kernel is configured, it is time to compile and install it. Exit
the configuration and start the compilation process:
Code Listing 3.7: Compiling the kernel
(64bit userland) # make && make modules_install
(32bit userland) # ppc64make && ppc64make modules_install
When the kernel has finished compiling, copy the kernel image to
/boot. Remember to replace <kernel-version<
with your actual kernel version:
Code Listing 3.8: Installing the kernel
# cp vmlinux /boot/<kernel-version<
Now continue with Configuring the Modules.
7.d. Configuring the Modules
You should list the modules you want automatically loaded in
/etc/modules.autoload.d/kernel-2.6. You can add extra
options to the modules too if you want.
To view all available modules, run the following find command. Don't
forget to substitute "<kernel version>" with the version of the kernel you
Code Listing 4.1: Viewing all available modules
# find /lib/modules/<kernel version>/ -type f -iname '*.o' -or -iname '*.ko'
For instance, to automatically load the 3c59x.o module, edit the
kernel-2.6 file and enter the module name in it.
Code Listing 4.2: Editing /etc/modules.autoload.d/kernel-2.6
# nano -w /etc/modules.autoload.d/kernel-2.6
Code Listing 4.3: /etc/modules.autoload.d/kernel-2.6
Continue the installation with Configuring
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