Re: [gentoo-embedded] x86 SBC Gentoo Embedded HowTo version 0.06 (almost finished)

[Yuri Vasilevski]

Hi,

On Mon, 6 Jun 2005 10:03:26 -0500
Heath H Holcomb <liquidcable@×××××.com> wrote:

> Version 0.06
> Please add, delete, modify. Thanks!

Just some things that came to my mind with respect to this
version.

> This procedure produces a working embedded rootfs, that boots form a hard
> drive on a Geode based SBC (single board computer); at least on my
> development system.
>
> I've update my website with this version also.
> http://www.bulah.com/embeddedgentoo.html
>
>
> #--------------------------------------------------------------------------------
> # Embedded Gentoo How-To for x86
> #
> # A how-to guide to setup a Gentoo embedded environment, you must be root.
> # These commands are to be run on your development system,
> # any x86 Gentoo Linux computer will do.  The system should be fast,
> # to speed development.  The target can be any x86 based SBC.  I'm
> # using a Geode based SBC.  Latter I'll use a Via based SBC.
> #
> # version 0.06
> # 2005.6.6
> #
> # Heath Holcomb (heath at bulah.com)
> # Ned Ludd (embedded Gentoo project lead, original commands posted)
> # Lloyd Sargent (contributor)
> # Yuri Vasilevshi (contributor)

It's Vasilevski :-)

> # Mike George (contributor)
> # Kammi Cazze (contributor)
> # Marius Schaefer (contributor)
> #
> # Definitions and Terms
> # system_rootfs = your regular rootfs
> # development_rootfs = what you use to build the embedded_rootfs
> # embedded_rootfs = rootfs you deploy to the target system
> # SBC = single board computer (here it's an x86 based)
> #
> # References
> # http://www.gentoo.org/doc/en/handbook/index.xml
> # http://www.epiawiki.org
> # http://epia.kalf.org
> # Gentoo embedded mailing list (gentoo-embedded@l.g.o)
> #
> #
> # Overview of process (steps)
> # 1 - Prepare the development_rootfs from your system_rootfs
> # 2 - Build the development_rootfs
> # 3 - Build the embedded_rootfs
> # 4 - Build and install non-system programs to the embedded_rootfs
> # 5 - Build and install a kernel to the embedded_rootfs
> # 6 - Deploy embedded_rootfs to target
> #
> #--------------------------------------------------------------------------------
>
> #----- Step 1 - Prepare the development_rootfs from your system_rootfs -------
>
> # You must be root.
> su -
>
> # Create the development_rootfs.
> # I use i586 because of target is a Geode processor.
> mkdir -p /opt/i586-gentoo-uclibc-linux/usr/portage
>
> # Download the latest stage 1 tarball.
> wget \
> http://gentoo.osuosl.org/experimental/x86/embedded/stages/stage1-x86-uclibc-2005.0.tar.bz2
>
> # Untar the stage to the development_rootfs.
> tar -xvjf stage1-x86-uclibc-2005.0.tar.bz2 -C /opt/i586-gentoo-uclibc-linux/

it should be tar -xvjpf ...
where -p stands for --preserve-permissions

>
> # Mount the proc and portage directories to your development_rootfs.
> # Makes your system_rootfs's proc and portage directory available from inside
> # of your development_rootfs (after chrooting).
> mount --bind /proc /opt/i586-gentoo-uclibc-linux/proc/
> mount --bind /usr/portage /opt/i586-gentoo-uclibc-linux/usr/portage
>
> # Copy over DNS information to the development_rootfs.
> cp /etc/resolv.conf /opt/i586-gentoo-uclibc-linux/etc/resolv.conf
>
> # Chroot into the development_rootfs.
> chroot /opt/i586-gentoo-uclibc-linux /bin/bash --login
>
>
> #----- Step 2 - Build the development_rootfs ---------------------------------
>
> # Create new environment and load variables into memory.
> env-update
> source /etc/profile
>
> # Modify make.conf file to your liking/needs.
> nano -w /etc/make.conf
> # This is for my target, Geode x86 processor.
> /*
> USE="bitmap-fonts minimal truetype-fonts uclibc mmx"

The uclibc USE flag was obsoleted, see:
http://www.mail-archive.com/gentoo-embedded@l.g.o/msg00140.html

> CHOST="i586-gentoo-linux-uclibc"
> CFLAGS="-march=i586 -Os -pipe -fomit-frame-pointer -mmmx"
> CXXFLAGS="${CFLAGS}"
> FEATURES="buildpkg"
>
> VIDEO_CARDS="chips"
> UCLIBC_CPU="586MMX"
> */
>
> # Set profile to use 2.6 kernel.
> # The current stage uses 2.4 by default, and for most cases you are going
> # to want a 2.6.x kernel.
> rm /etc/make.profile

This are equivalent but I would use:
unlink /etc/make.profile
for clarity's sake.

> ln -s /usr/portage/profiles/uclibc/x86 /etc/make.profile
>
> # Start the bootstrap script.
> cd /usr/portage/scripts
> ./bootstrap.sh -p -v
> ./bootstrap.sh
>
> # Workaround 1
> # Failure compiling uclibc (gcc-config error: Could not run/locate "gcc")?
> # If you get a failure while bootstrap is compileing uclibc here are the steps
> # to work around the problem.
> gcc-config 1
> source /etc/profile
> ./bootstrap.sh
>
> # Emerge the system ebuild for the development_rootfs.
> emerge -e system
>
> # Workaround 2
> # During emerge -e system, python-fchksum failes complaing about
> # gcc-config error: Could not run/locate "i386-gentoo-linux-uclibc-gcc"
> # The following commands work around this problem.
> emerge python
> emerge -e system
>
>
> #----- Step 3 - Build the embedded_rootfs ------------------------------------
>
> # Create the embedded_rootfs directory.
> mkdir /embedded_rootfs
>
> # Emerge baselayout-lite into embedded_rootfs.
> # This gives your system a basic file structure.
> # 1.0_pre1 is the only one that is stable, right?
> cd /usr/portage/sys-apps/baselayout-lite/
> ROOT=/embedded_rootfs emerge baselayout-lite-1.0_pre1.ebuild
>
> # Workaround 3
> # Baselayout-lite is still beta, so a few fixes are needed.
> # There needs to be a directory "log" in /var.
> # Inittab calls for /usr/bin/tail, but it needs to /usr/bin.
> mkdir /embedded_rootfs/var/log
> nano -w /embedded_rootfs/etc/inittab
> /*
> #tty3::respawn:/usr/bin/tail -f /var/log/messages
> tty3::respawn:/bin/tail -f /var/log/messages
> */
>
> # Emerge uclibc into the embedded_rootfs.
> # Use the -K option because we don't get the extra files created by the
> # build/emerge process into our embedded rootfs which needs to be as
> # small as possible.
> ROOT=/embedded_rootfs emerge -K uclibc
>
> # Emerge busybox into the embedded_rootfs.
> # First you must emerge it into your development_rootfs.
> # This does not create the symlinks in our development embedded rootfs.
> emerge busybox
> ROOT=/embedded_rootfs emerge -K busybox
>
> # Create the symlinks for busybox in the embedded_rootfs.

I have not used it, but form the ebuild it looks like
if you emerge busybox with make-symlinks in USE flags
it'll just make them for you. I think the proper way
may be (gain, this is just by looking at the ebuild):
VERY_BRAVE_OR_VERY_DUMB=yes USE=make-symlinks emerge -B busybox
(this will just make the package without installing it
to the system and consequently without braking it with
the symlinks)
ROOT=/embedded_rootfs emerge -K busybox
(at this point the busybox binary package should have
the symlinks in it)

> mkdir /embedded_rootfs/proc
> mount -o bind /proc/ /embedded_rootfs/proc/
> chroot /embedded_rootfs /bin/busybox --install -s
> umount /embedded_rootfs/proc
>
> # Set time zone in your embedded_rootfs.
> # See http://leaf.sourceforge.net/doc/guide/buci-tz.html for details.
> # For central standard time in the US, use "CST6CDT".
> nano -w /embedded_rootfs/etc/TZ
> /*
> CST6CDT
> */
>
> # Install a boot loader (usually grug or lilo).
> # Once you copy/deploy your embedded_rootfs program to you target SBC you will
> # have to run the grub on the command line to write to the master boot record
> # (MBR).
> # Ncurses is needed by grub, if you are not using gurb then you don't need
> # ncurses. For some reason not all of /boot/grub is copied over to the
> # embedded_rootfs, so a extra manual copy step is needed.
> ROOT=/embedded_rootfs emerge -K ncurses
> emerge grub
> ROOT=/embedded_rootfs emerge -K grub
> cp -R /boot/grub /embedded_rootfs/boot/

Why not installing grub with static USE flag?
I think ncurses is to expensive (big) to have if it is used
just by grub.
Another option will be to install install grub with:
ROOT=/embedded_rootfs emerge -K --nodeps grub
rm -f /embedded_rootfs/sbin/grub
As we can still use grub-install that doesn't need ncurses.

>
> # Modify your boot configure file.
> # The example below is for a gurb, for a boot partition on /dev/hda1 and only
> # one partition on the target SBC system.
> nano -w /embedded_rootfs/boot/grub/grub.conf
> /*
> default 0
> timeout 10
> splashimage=(hd0,0)/boot/grub/splash.xpm.gz
>
> title=Linux 2.6.x
> root (hd0,0)
> kernel /vmlinuz-2.6.x root=/dev/hda1 vga=792
> */
>
> # Set root password
> ROOT=/embedded_rootfs passwd
>
> # Modify fstab.
> # Below is mine, yours may vary.
> nano -w /embedded_rootfs/etc/fstab
> /*
> /dev/hda1		/		reiserfs	defaults	0 0
> none			/proc		proc		defaults  	0 0
> none			/sys		sysfs		defaults	0 0
> none			/dev/shm	tmpfs	defaults	0 0
> */
>
> #---- Step 4 - Build and install non-system programs to the embedded_rootfs --
>
> # Emerge other software you need for you embedded target.
> # This is very wildly depending on your needs.
> # Also your proprietary application will be done here.
> emerge foobar*
> ROOT=/embedded_rootfs emerge -K foobar*
>
>
> #---- Step 5 - Build and install a kernel to the embedded_rootfs -------------
>
> # Install a kernel into embedded_rootfs.
> # First we will emerge it into our development_rootfs, then configure and
> # build it.
> emerge vanilla-sources
> cd /usr/src/
> cd linux
> make menuconfig
> # configure your kernel for your TARGET SBC here
> make
> ROOT=/embedded_rootfs make modules_install
> cp /usr/src/linux/arch/i386/boot/bzImage /embedded_rootfs/boot/vmlinuz-2.6.x
>
> # A few notes on compiling your kernel.
> # If deploying to Compact Flash/DiskOnChip/SD us ext2, as the journaling
> # filing systems "write" to much for a flash device.
> # If deploying to a hard drive use a journaling filing system, such as
> # ext3 or reiserfs.
>
>
> #---- Step 6 - Deploy embedded_rootfs to target ------------------------------
>
> # Prepare a Gentoo (or any Linux distro) system on the target SBC using a
> # harddrive.  This is known as the target development rootfs.
> # We will create a partition (/embedded_rootfs) that will server as our
> # "test" partition to deploy our embedded_rootfs that we generate on our
> # development_system.
> #
> # I use the following partitions to speed development (yours may vary):
> # /dev/hda1 - /embedded_rootfs - 1 GB
> # /dev/hda2 - /boot - 100 MB
> # /dev/hda3 - swap - (size varies, 512 MB is a good number)
> # /dev/hda4 - / - (what is left, at least 1.5 GB per 2005.0 install guide
> specs)
> #
> # Copy over your embedded_rootfs from you development system to your target
> # system and the directory /embedded_rootfs.  This needs to be done via NFS as
> # need to preserve the permissions.
> #
> #The following commands are done from the
> # target development rootfs.
> mount -t reiserfs /dev/hda1 /mnt/embedded_rootfs
> mount -t nfs
> 192.168.0.10:/opt/i586-gentoo-uclibc-linux/embedded_rootfs /mnt/transfer
> cp -adpR /mnt/transfer/* /mnt/embedded_rootfs
>
>
> # Modify your target system's gurb.conf (or lilo.conf) for allow you to boot
> # to the embedded_rootfs partition.
> #
> # Reboot, and if all goes well you'll be greeted with a login prompt.
> #
> # Fin.

Yuri.
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