Difference between revisions of "Genkernel Quick Start Tutorial"

(Third step: Building and installing the kernel)
 
m
Line 20: Line 20:
 
This is achieved with:
 
This is achieved with:
  
<pre>
+
<console>
# emerge sys-kernel/gentoo-sources sys-kernel/genkernel
+
##i### emerge sys-kernel/gentoo-sources sys-kernel/genkernel
</pre>
+
</console>
  
 
Once the Gentoo kernel sources are deployed, you should find a directory named '''linux-''version''-gentoo''' (e.g. linux-2.6.39-gentoo) under '''/usr/src'''. Update the '''linux''' symlink to point on this directory:
 
Once the Gentoo kernel sources are deployed, you should find a directory named '''linux-''version''-gentoo''' (e.g. linux-2.6.39-gentoo) under '''/usr/src'''. Update the '''linux''' symlink to point on this directory:
<pre>
+
<console>
# cd /usr/src
+
##i### cd /usr/src
# rm linux
+
##i### rm linux
# ln -s linux-2.6.39-gentoo linux
+
##i### ln -s linux-2.6.39-gentoo linux
</pre>
+
</console>
  
 
== Second step: Grabbing and tweaking a configuration file ==
 
== Second step: Grabbing and tweaking a configuration file ==
Line 35: Line 35:
 
How to start your kernel configuration? Simply by using the same configuration template the running System Rescue CD kernel had been built with! Before chrooting in your Funtoo instance, you did something like:
 
How to start your kernel configuration? Simply by using the same configuration template the running System Rescue CD kernel had been built with! Before chrooting in your Funtoo instance, you did something like:
  
<pre>
+
<console>
# mount -o bind /proc /mnt/gentoo/proc
+
##i### mount -o bind /proc /mnt/gentoo/proc
</pre>
+
</console>
 
Or:
 
Or:
<pre>
+
<console>
# mount -t proc none /mnt/gentoo/proc
+
##i### mount -t proc none /mnt/gentoo/proc
</pre>
+
</console>
  
 
In your chroot environment (or from a System Rescue CD virtual terminal) if you look what /proc contains you will notice a file named config.gz:
 
In your chroot environment (or from a System Rescue CD virtual terminal) if you look what /proc contains you will notice a file named config.gz:
  
<pre>
+
<console>
# ls /proc
+
##i### ls /proc
 +
 
 
...
 
...
 
dr-xr-xr-x  7 root      root                    0 May 23 03:13 952
 
dr-xr-xr-x  7 root      root                    0 May 23 03:13 952
Line 56: Line 57:
 
-r--r--r--  1 root      root                    0 May 23 22:27 cpuinfo
 
-r--r--r--  1 root      root                    0 May 23 22:27 cpuinfo
 
...
 
...
</pre>
+
</console>
  
 
config.gz holds the running kernel (System Rescue CD) configuration, just copy the gunziped content in the Gentoo sources directory:
 
config.gz holds the running kernel (System Rescue CD) configuration, just copy the gunziped content in the Gentoo sources directory:
  
<pre>
+
<console>
# cd /usr/src/linux
+
##i### cd /usr/src/linux
# zcat /proc/config.gz > .config
+
##i### zcat /proc/config.gz > .config
</pre>
+
</console>
  
 
Next, run make oldconfig to set all newly added options:
 
Next, run make oldconfig to set all newly added options:
  
<pre>
+
<console>
# make oldconfig
+
##i### make oldconfig
</pre>
+
</console>
  
 
Next, tweak the kernel configuration in the way you prefer (manually edition of the .config file, make nconfig, make menuconfig....) if you wish. You are not ready yet! A final step is required: '''you ''must'' either set CONFIG_INITRAMFS_SOURCE to a blank value (CONFIG_INITRAMFS_SOURCE="") either delete the statement in the .config file'''. Forgotting to do that will make Genkernel abort the compilation process with a message like:
 
Next, tweak the kernel configuration in the way you prefer (manually edition of the .config file, make nconfig, make menuconfig....) if you wish. You are not ready yet! A final step is required: '''you ''must'' either set CONFIG_INITRAMFS_SOURCE to a blank value (CONFIG_INITRAMFS_SOURCE="") either delete the statement in the .config file'''. Forgotting to do that will make Genkernel abort the compilation process with a message like:
  
<pre>
+
<console>
 
/usr/src/linux-2.6.39-gentoo/scripts/gen_initramfs_list.sh: Cannot open '/var/tmp/genkernel/initramfs-2.6.32.14-std155-i386.cpio.gz'
 
/usr/src/linux-2.6.39-gentoo/scripts/gen_initramfs_list.sh: Cannot open '/var/tmp/genkernel/initramfs-2.6.32.14-std155-i386.cpio.gz'
 
make[1]: *** [usr/initramfs_data.cpio.lzma] Error 1
 
make[1]: *** [usr/initramfs_data.cpio.lzma] Error 1
</pre>
+
</console>
  
 
== Third step: Building and installing the kernel ==
 
== Third step: Building and installing the kernel ==
Line 82: Line 83:
 
This is simply achieved by:
 
This is simply achieved by:
  
<pre>
+
<console>
# genkernel --no-mrproper all
+
##i### genkernel --no-mrproper all
</pre>
+
</console>
  
 
The same remarks written in the [[Genkernel_Quick_Start_Tutorial#Third_step:_Building_and_installing_the_kernel|third paragraph]] of the first use case are still valid here.
 
The same remarks written in the [[Genkernel_Quick_Start_Tutorial#Third_step:_Building_and_installing_the_kernel|third paragraph]] of the first use case are still valid here.
  
 
[[Category:Kernel]]
 
[[Category:Kernel]]

Revision as of 14:27, 9 January 2014

Genkernel is a tool which help you to build a Linux kernel and deploy it along with a ramdisk image which contains all of the necessary modules to make the kernel being able to mount the different partitions of your harddrives in the VFS at the system startup.

Concepts

TBC

Recompiling the Gentoo kernel sources from a SystemRescue CD chroot

A second case that many Funtoo users will face to is to compile their own kernel when installing a brand new Funtoo instance from a stage 3 archive (the most common scenario is to boot the machine with SystemRescue CD).

Note

If you want to use the System rescue CD sources provided by Funtoo ( sys-kernel/sysrescue-std-sources ), the philosophy remains exactly the same

First step emerging the required packages

The first step is to emerge:

  1. The Gentoo kernel sources
  2. Genkernel itself

This is achieved with:

# emerge sys-kernel/gentoo-sources sys-kernel/genkernel

Once the Gentoo kernel sources are deployed, you should find a directory named linux-version-gentoo (e.g. linux-2.6.39-gentoo) under /usr/src. Update the linux symlink to point on this directory:

# cd /usr/src
# rm linux
# ln -s linux-2.6.39-gentoo linux

Second step: Grabbing and tweaking a configuration file

How to start your kernel configuration? Simply by using the same configuration template the running System Rescue CD kernel had been built with! Before chrooting in your Funtoo instance, you did something like:

# mount -o bind /proc /mnt/gentoo/proc

Or:

# mount -t proc none /mnt/gentoo/proc

In your chroot environment (or from a System Rescue CD virtual terminal) if you look what /proc contains you will notice a file named config.gz:

# ls /proc

...
dr-xr-xr-x  7 root       root                     0 May 23 03:13 952
dr-xr-xr-x  7 root       root                     0 May 23 03:13 953
dr-xr-xr-x  7 root       root                     0 May 23 18:42 9834
...
-r--r--r--  1 root       root                 16024 May 23 22:27 config.gz
-r--r--r--  1 root       root                     0 May 23 22:27 consoles
-r--r--r--  1 root       root                     0 May 23 22:27 cpuinfo
...

config.gz holds the running kernel (System Rescue CD) configuration, just copy the gunziped content in the Gentoo sources directory:

# cd /usr/src/linux
# zcat /proc/config.gz > .config

Next, run make oldconfig to set all newly added options:

# make oldconfig

Next, tweak the kernel configuration in the way you prefer (manually edition of the .config file, make nconfig, make menuconfig....) if you wish. You are not ready yet! A final step is required: you must either set CONFIG_INITRAMFS_SOURCE to a blank value (CONFIG_INITRAMFS_SOURCE="") either delete the statement in the .config file. Forgotting to do that will make Genkernel abort the compilation process with a message like:

/usr/src/linux-2.6.39-gentoo/scripts/gen_initramfs_list.sh: Cannot open '/var/tmp/genkernel/initramfs-2.6.32.14-std155-i386.cpio.gz'
make[1]: *** [usr/initramfs_data.cpio.lzma] Error 1

Third step: Building and installing the kernel

This is simply achieved by:

# genkernel --no-mrproper all

The same remarks written in the third paragraph of the first use case are still valid here.