[aarch64-port-dev ] OpenJDK8/Zero cross compile build for Foundation model

Mon Jun 17 05:50:24 PDT 2013

Hi all,

I have got a cross compile build of OpenJDK8/Zero working for the ARM 
foundation model (ARM's aarch64 simulator).

I have made binaries of the images available should people wish to try 
this out directly, and I have also included details on how to build from 
the source below.

Firstly the build in OpenJDK8 has been changed completely. The top level 
jdk8 directory now contains a ./configure. This has a 
--with-jvm-variants= argument. From jdk8-b85 onwards it is possible to 
build zero out of the box by simply doing

./configure --with-jvm-variants=zero
make

The support for cross compiling also seems to have been vastly improved. 
The following options are available to ./configure.

--with-sys-root= <location of your cross compile sysroot>
--openjdk-target= <cross compile 'target'>

Armed with these options, a properly configured sysroot and a few 
patches as given below it was possible to get OpenJDK cross compiling 
for aarc64 with relatively little difficulty.

Well done to those who worked on the new build system in OpenJDK8 - it 
is a vast improvement.

Setting up and running the binaries
-----------------------------------------------

First of all I will described how you can download the Foundation model 
(ARM's aarch64 simulator) and get a Java binary up and running.

Note: In all of the below I am running Fedora 18 x86 64 bit. Your 
mileage on other OS/Distro may vary.

First of all you will need to download the foundation model from ARM's 
website at

http://www.arm.com/products/tools/models/fast-models/foundation-model.php

At the bottom of the page under "Get started with Foundation Models" 
click on "download now". You will be asked to login. If you have 
prevously registered for an ARM account login, otherwise you will need 
to check the license terms, ensure that you are happy with them and 
register for an ARM account.

After logging in above, on the right hand side of the next page under 
"ARM V8 Foundation Model" click "Download Now".

The name of the file I downloaded was "FM000-KT-00035-r0p8-48rel5.tgz". 
Obviously the name of the file you download may differ depending on the 
version number you download, but if you want to download exactly the 
same version number you can look for it under "Display older versions".

Untar this archive. It will create a directory 'Foundation_v8pkg'. cd to 
this directory

tar xfz FM000-KT-00035-r0p8-48rel5.tgz
cd Foundation_v8pkg

Next you will need to download a boot image and an SD disk image.

To download the boot image do

wget 
http://releases.linaro.org/13.05/openembedded/aarch64/img-foundation.axf

The SD disk image may be downloaded from

http://people.linaro.org/~edward.nevill/sd.img.gz

Decompress it using

gzip -d sd.img.gz

To boot the image in the foundation model do

./models/Linux64_GCC-4.1/Foundation_v8 --image img-foundation.axf 
--block-device sd.img --network=nat

Now, an xterm window will open and Linux will boot in the aarch64 
simulator. After a short while you will get the root '#' prompt. The 
root home directory has been pre populated with the following

# ls
Queens.class
Queens.java
ecm
j2re-image
j2sdk-image

Some things you can try. In each case be prepared to wait, it hasn't 
crashed, it is running under a simulator.

./jsdk-image/bin/javac Queens.java
./j2re-image/bin/java Queens
cd ecm
../j2re-image/bin/java CaffeineMarkEmbeddedApp

If you want to download more Java programs to you image follow the 
instructions at the end of the next section for mounting the sd.img on 
your host.

Please be careful to shut down the simulator properly before mounting 
the file system on your host machine. Otherwise you *will* corrupt the 
filesystem!

To shutdown the simulator do

shutdown -h now

Then, when the simulator says "system halted" use CTRL-C to stop it.

Building the OpenJDK8/zero image
----------------------------------------------

For convenience I have provided a complete build tree and a populated 
sysroot below. Details of how to fetch and patch the OpenJDK8 source, 
and how to build your own sysroot are given later, but to get started 
you may find it more convenient just to download the images below.

The OpenJDK8 source tree:-

http://people.linaro.org/~edward.nevill/aa64_openjdk_130606.tar.gz

The sysroot

http://people.linaro.org/~edward.nevill/sysroot.tar.gz

Untar the 1st achive aa64_openjdk_130606.tar.gz. This will create a 
directory aa64_openjdk.

cd to that directory and untar the 2nd archive, sysroot.tar.gz.

tar xfz ~/Downloads/aa64_openjdk_130606.tar.gz
cd aa64_openjdk
tar xfz ~/Downloads/sysroot.tar.gz

Then just execute the 'do_configure' and 'do_compile' scripts contained 
in the aa64_openjdk directory and all being well, some time later, you 
should have a j2sdk and a j2re image.

./do_configure
./do_compile 2>&1 | tee log

To transfer the compiled j2sdk and 2re images to the SD card image do 
the following.

Be very careful to shut down the simulator before attempting the 
following. If you attempt to mount the sd.img file as described below, 
while you are running a simulator which also has it mounted you *will* 
corrupt the filesystem.

sudo mount -o loop,offset=54525952 sd.img /mnt
sudo cp -r 
<...>/aa64_openjdk/jdk8/build/linux-aarch64-normal-zero-release/j2sdk-image 
/mnt/home/root
sudo cp -r 
<...>/aa64_openjdk/jdk8/build/linux-aarch64-normal-zero-release/j2re-image 
/mnt/home/root
sudo umount /mnt

You may then reboot the simulator with the upated image as described above.

Rebuilding from scratch
--------------------------------

To rebuild from scratch you will first of all need to build and populate 
a sysroot.

The easiest way to do this is to use Open Embedded.

mkdir fromscratch
cd fromscratch
git clone git://git.linaro.org/openembedded/jenkins-setup.git
cd jenkins-setup
bash init-and-build.sh
cd openembedded-core
source oe-init-build-env ../build
bitbake -k openjdk-7-jre

Note: The reason for doing openjdk-7-jre is that we want to ensure that 
all the packages required to build openjdk are included in the sysroot. 
We are not actually going to use openjdk-7-jre in the build.

The above command will take several hours.

Now cd to the 'fromscratch' directory created above.

cd ~/fromscratch

Create a symbolic link to the sysroots created in the Open Embedded 
build above

ln -s jenkins-setup/build/tmp-eglibc/sysroots sysroots

Download the OpenJDK source from openjdk.java.net

hg clone http://hg.openjdk.java.net/jdk8/jdk8
cd jdk8
sh ./get_source.sh

Update everything to jdk8-b92

sh ./common/bin/hgforest.sh up -r jdk8-b92

Download and untar the patches

http://people.linaro.org/~edward.nevill/patches.tar

cd ~/fromscratch
tar xf patches.tar
cd jdk8
patch -p 1 < ../patches/jdk8_patches
cd jdk
patch -p 1 < ../../patches/jdk_patches
cd ../hotspot
patch -p 1 < ../../patches/hotspot_patches

Download the 'do_configure' and 'do_compile' scripts. First make sure 
you cd to the ~/fromscratch directory above.

cd ~/fromscratch

http://people.linaro.org/~edward.nevill/do_configure
http://people.linaro.org/~edward.nevill/do_compile

Then execute do_configure and do_compile

bash do_configure
bash do_compile 2>&1 | tee log

All being well, within a few minutes you should have a j2sdk and j2re image!

If you run into difficulties with any of this please drop me an email.

All the best,

Edward Nevill