Gentoo Oracle JDK on ARM

Mar 19 2014 Published by under Linux

Installing a JDK on ARM has several challenges. First, there is no binary icedtea for ARM. Second, building icedtea generates circular build time dependencies.
On my first attempt, I just ran the following commands:

emerge --autounmask-write virtual/jdk
emerge virtual/jdk

However, it soon met an error:

(controller) sabre2 ~ # cat /var/tmp/portage/dev-java/icedtea-bin-
 * Package:    dev-java/icedtea-bin-
 * Repository: gentoo
 * Maintainer:
 * USE:        alsa arm elibc_glibc kernel_linux userland_GNU
 * FEATURES:   preserve-libs sandbox userpriv usersandbox
>>> Unpacking source...
 * ERROR: dev-java/icedtea-bin- failed (unpack phase):
 *   Nothing passed to the 'unpack' command
 * Call stack:
 *, line   93:  Called src_unpack
 *        environment, line 2546:  Called unpack
 *, line  291:  Called die
 * The specific snippet of code:
 *      [ -z "$*" ] && die "Nothing passed to the 'unpack' command"
 * If you need support, post the output of `emerge --info '=dev-java/icedtea-bin-'`,
 * the complete build log and the output of `emerge -pqv '=dev-java/icedtea-bin-'`.
 * The complete build log is located at '/var/tmp/portage/dev-java/icedtea-bin-'.
 * The ebuild environment file is located at '/var/tmp/portage/dev-java/icedtea-bin-'.
 * Working directory: '/var/tmp/portage/dev-java/icedtea-bin-'
 * S: '/var/tmp/portage/dev-java/icedtea-bin-'

Later, when I checked on gentoo-packages, it didn’t have an arm ebuild. Oracle has hardfloat and softfloat binary JDKs for ARM, so I went on to install them. They can be used to bootstrap an icedtea build.

# emerge -av dev-java/oracle-jdk-bin

 * IMPORTANT: 1 news items need reading for repository 'gentoo'.
 * Use eselect news to read news items.

 * Last emerge --sync was 92d 19h 31m 27s ago.

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] media-fonts/dejavu-2.33  USE="-X -fontforge" 4,767 kB
[ebuild  N     ] media-libs/freetype-2.4.11:2  USE="bindist bzip2 -X -auto-hinter -debug -doc -fontforge (-infinality) -static-libs -utils" 1,510 kB
[ebuild  N     ] virtual/ttf-fonts-1  0 kB
[ebuild  N     ] media-libs/fontconfig-2.10.92:1.0  USE="-doc -static-libs" 1,490 kB
[ebuild  N     ] app-admin/eselect-fontconfig-1.0  0 kB
[ebuild  N F  *] dev-java/oracle-jdk-bin-  USE="fontconfig -X -alsa
-derby -doc -examples -jce -nsplugin -pax_kernel -source" 138,494 kB

Total: 6 packages (6 new), Size of downloads: 146,260 kB
Fetch Restriction: 1 package (1 unsatisfied)

Fetch instructions for dev-java/oracle-jdk-bin-
 * Oracle requires you to download the needed files manually after
 * accepting their license through a javascript capable web browser.
 * Download the following files:
 *   jdk-7u40-linux-arm-vfp-sflt.tar.gz
 *   jdk-7u40-linux-arm-vfp-hflt.tar.gz
 * at ''
 * and move them to '/distfiles'

The following keyword changes are necessary to proceed:
 (see "package.accept_keywords" in the portage(5) man page for more details)
# required by dev-java/oracle-jdk-bin (argument)
=dev-java/oracle-jdk-bin- **

The following license changes are necessary to proceed:
 (see "package.license" in the portage(5) man page for more details)
# required by dev-java/oracle-jdk-bin (argument)
>=dev-java/oracle-jdk-bin- Oracle-BCLA-JavaSE

NOTE: The --autounmask-keep-masks option will prevent emerge
      from creating package.unmask or ** keyword changes.

Use --autounmask-write to write changes to config files (honoring
CONFIG_PROTECT). Carefully examine the list of proposed changes,
paying special attention to mask or keyword changes that may expose
experimental or unstable packages.

You may not have a browser installed on your ARM board, so I suggest just uploading the Oracle tarballs to a server and using wget to download them.
To fix the control panel error when you don’t have a desktop environment installed, you need to remove lines from the ebuild and digest it.

vim /usr/portage/dev-java/oracle-jdk-bin/oracle-jdk-bin-

These lines need to be removed:

    newicon jre/lib/desktop/icons/hicolor/48x48/apps/sun-jcontrol.png \
        sun-jcontrol-${PN}-${SLOT}.png || die
    sed -e "s#Name=.*#Name=Java Control Panel for Oracle JDK ${SLOT}#" \
        -e "s#Exec=.*#Exec=/opt/${P}/jre/bin/jcontrol#" \
        -e "s#Icon=.*#Icon=sun-jcontrol-${PN}-${SLOT}#" \
        -e "s#Application;##" \
        -e "/Encoding/d" \
        jre/lib/desktop/applications/sun_java.desktop \
        > "${T}"/jcontrol-${PN}-${SLOT}.desktop || die
    domenu "${T}"/jcontrol-${PN}-${SLOT}.desktop

Once removed, generate the manifest for it.

ebuild /usr/portage/dev-java/oracle-jdk-bin/oracle-jdk-bin- digest

If you run emerge dev-java/oracle-jdk-bin, it will succeed.

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Gentoo on SABRE Lite

Jan 23 2014 Published by under Linux

I recently received several SABRE Lite BD-SL-i.MX6 boards for running ARM benchmarks on DataMill. To install Gentoo on it, you need a USB-to-serial cable converter. It came with a 4GB SD card, which is large enough to get you started.
Overview of the installation:

  • Reset board and format SD card (optional)
  • Compile kernel with btrfs support (optional)
  • Copy boot script and kernel
  • Extract stage3 and portage snapshot
  • Configure the install
  • Backup and clone (optional)

Reset board and format SD card

When I first tried to boot images extracted to the SD card on the board, it always got stuck at the U-Boot prompt. It turned out that there were environment variables left over from previous uses for these boards. Here is the way to reset board variables:

U-Boot > run clearenv
U-Boot > reset

After I managed to boot Linux images on it, I went onto formatting the card for a Gentoo install. I used sfdisk so that formatting can be scripted with a file which I saved as mmc_partitions:

# partition table of /dev/sdd
unit: sectors

/dev/sdd1 : start=     2048, size=   102400, Id=83
/dev/sdd2 : start=   104448, size=  7669760, Id=83
/dev/sdd3 : start=        0, size=        0, Id= 0
/dev/sdd4 : start=        0, size=        0, Id= 0

I formatted the second partition as btrfs so that compression could be used on the small SD card. You may want to format it as ext3 to save time. If you have problems getting it to boot, check to make sure your btrfs-progs are not newer than the btrfs version the kernel is built to support. sys-fs/btrfs-progs-0.20_rc1 worked for the January 2014 kernel source.

# sfdisk -f /dev/sdd < mmc_partitions
# mkfs.btrfs -f /dev/sdd2 && mkfs.ext2 /dev/sdd1

Compile kernel with btrfs support

The git tree for the kernel is available at There are two main branches, one for Android and one for non-Android. Use the most recent one for non-Android.

# wget
# unzip
# cd linux-imx6-boundary-imx_3.0.35_4.0.0
# make ARCH=arm imx6_defconfig
# vim .config

Make the following changes to the kernel config:


Gentoo requires a devtmpfs filesystem to mount at /dev while selecting btrfs also selects LIBCRC32C. The CRC32c CRC algorithm is used by btrfs for checksums.
Now cross compile the kernel

# make -j9 ARCH=arm CROSS_COMPILE=armv7a-unknown-linux-gnueabi- uImage

Copy boot script and kernel

Download 6x_bootscript-20121110 available from a blog post and rename it 6x_bootscript. Get the kernel from one of the i.MX6 builds if you decided to skip building it.

# mount -o compress=zlib /dev/sdd2 /mnt/p1 && mkdir /mnt/p1/boot && mount /dev/sdd1 /mnt/p1/boot
# cp 6x_bootscript /mnt/p1/boot
# cp uImage /mnt/p1/boot

uImage is located in /usr/src/linux/arch/arm/boot if you compiled the kernel.

Extract stage3 and portage snapshot

Download the latest stage3 tarball and extract it

tar xjpf stage3-armv7a*.tar.bz2 -C /mnt/p1

BD-SL-i.MX6 with serial cable
If you get errors trying to run emerge --sync, it is because downloading the portage tree is not optional unlike other guides indicate. Simply download it from your nearest mirror and extract it

# tar xjpf portage-latest.tar.bz2 -C /mnt/p1/usr

Configure the install

If you compiled the kernel with btrfs, edit /mnt/p1/etc/fstab file so that zlib compression is enabled

/dev/mmcblk0p1          /boot           ext2            noatime         0 1
/dev/mmcblk0p2          /               btrfs            noatime,compress=zlib
       0 1

Set kernel boot argument in /mnt/p1/etc/inittab. Change the console= argument to ttymxc1. eg "$bootargs console=ttymxc1,115200 vmalloc=400M consoleblank=0 rootwait"
The rest of the process is the same as for other ARM boards, such as the Trimslice. The guide for it is available at
4 SABRE Lite i.mx6 Development Boards on the benchmark rack

Backup and clone

First make the backup in a folder

cd /backups
tar -cvpzf backup.tar.gz /mnt/p1/

After unmounting the SD card and testing it on the device, put in a new one and clone it with the following commands

sfdisk -f /dev/sdd < mmc_partitions
mkfs.btrfs -f /dev/sdd2 && mkfs.ext2 -FF /dev/sdd1
mount -o compress=zlib /dev/sdd2 /mnt/p1 && mkdir /mnt/p1/boot && mount /dev/sdd1 /mnt/p1/boot
tar xzpf backup.tar.gz -C /mnt/p1
vim /mnt/p1/etc/conf.d/hostname

umount /mnt/p1/boot && umount /mnt/p1

The Funtoo ARM Guide has up to date sections on setting the root password and using swclock. If you decide to use swclock, update the last shutdown time to set the clock with touch /tmp/mnt/p1/lib/rc/cache/shutdowntime after extracting the tarball.

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