User Guide 

Contents

Notice 

The Total Compute 2020 (TC0) software stack uses the Yocto project to build a Board Support Package (BSP) and a choice of Poky Linux distribution or Android userspace. The Yocto project uses Bitbake to build the software stack.

Prerequisites 

These instructions assume that:

Your host PC is running Ubuntu Linux 18.04 LTS.
You are running the provided scripts in a bash shell environment.

The following utilities must be available on your host PC:

chrpath
compression library
diffstat
gawk
makeinfo
openssl headers
pip
repo

To resolve these dependencies, run:

sudo apt-get update
sudo apt-get install chrpath gawk texinfo libssl-dev diffstat wget git-core unzip gcc-multilib \
 build-essential socat cpio python python3 python3-pip python3-pexpect xz-utils debianutils \
 iputils-ping python3-git python3-jinja2 libegl1-mesa libsdl1.2-dev pylint3 xterm git-lfs openssl \
 curl lib32ncurses5-dev libz-dev python-pip u-boot-tools m4 zip

To get the latest repo tool from google, run the following commands:

mkdir -p ~/bin
curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
chmod a+x ~/bin/repo
export PATH=~/bin:$PATH

If syncing and building android, the minimum requirements for the host machine can be found at https://source.android.com/setup/build/requirements, These include:

At least 250GB of free disk space to check out the code and an extra 150 GB to build it. If you conduct multiple builds, you need additional space.
At least 16 GB of available RAM/swap.
Git configured properly using “git config” otherwise it may throw error while fetching the code.

Syncing and building the source code 

There are two distros supported in the TC0 software stack: poky (a minimal distro containing busybox) and android.

To sync code for poky, please follow the steps in “Syncing code” section for BSP only. To sync code for android, please follow the steps for syncing both BSP and Android.

To build the required binaries for poky, please follow the steps in “Board Support Package build” section only. To build the binaries for Android, please follow the steps in both “Board Support Package build” and “Android OS build” sections.

Syncing code 

Create a new folder that will be your workspace, which will henceforth be referred to as <tc0_workspace> in these instructions.

mkdir <tc0_workspace>
cd <tc0_workspace>
export TC0_RELEASE=refs/tags/TC0-2021.07.31

To sync BSP only without Android, run the repo command.

repo init -u https://gitlab.arm.com/arm-reference-solutions/arm-reference-solutions-manifest -m tc0.xml -b ${TC0_RELEASE} -g bsp
repo sync -j$(nproc)

To sync both the BSP and Android, run the repo command.

repo init -u https://gitlab.arm.com/arm-reference-solutions/arm-reference-solutions-manifest -m tc0.xml -b ${TC0_RELEASE} -g android
repo sync -j$(nproc)

Board Support Package build 

cd <tc0_workspace>/bsp
export DISTRO="poky"
export MACHINE="tc0"
source setup-environment
bitbake tc0-artifacts-image

The initial clean build will be lengthy, given that all host utilities are to be built as well as the target images. This includes host programs (python, cmake, etc.) and the required toolchain(s).

Once the build is successful, all images will be placed in the <tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0 directory.

Note that the BSP includes the Poky Linux distribution, which offers BusyBox-like utilities.

Android OS build 

Two profiles are supported:

tc0_swr : This supports Android display with swiftshader (software rendering).
tc0_nano : This supports headless Android and provides a good runtime environment for testing shell-based applications.

The android images can be built with or without authentication enabled using Android Verified Boot(AVB). AVB build is done in userdebug mode and takes a longer time to boot as the images are verified.

The build-scripts/tc0/build_android.sh script in <tc0_workspace>/android will patch and build android. This can be passed 2 parameters, -d for deciding which profile to build and -a for enabling AVB. The following command shows the help menu for the script:

cd <tc0_workspace>/android
./build-scripts/tc0/build_android.sh  -h
Incorrect script use, call script as:
<path to build_android.sh> [OPTIONS]
OPTIONS:
-d, --distro                            distro version, values supported [android-nano, android-swr]
-a, --avb                               [OPTIONAL] avb boot, values supported [true, false], DEFAULT: false

As an example, to build android with software rendering and AVB enabled, run the command:

./build-scripts/tc0/build_android.sh -d android-swr -a true

To build headless android without AVB, run the command:

./build-scripts/tc0/build_android.sh -d android-nano

Android based stack takes considerable time to build, so start the build and go grab a cup of coffee!

Provided components 

Within the Yocto project, each component included in the TC0 software stack is specified as a Bitbake recipe. The TC0 recipes are located at <tc0_workspace>/bsp/layers/meta-arm/.

Yocto allows modifying the fetched source code of each recipe component in the workspace, by applying patches. This is however not a convenient approach for developers, since creating patches and updating recipes is time-consuming. To make that easier, Yocto provides the devtool utility. Devtool creates a new workspace, in which you can edit the fetched source code and bake images with the modifications

cd <tc0_workspace>/bsp
MACHINE=tc0
DISTRO=poky
. ./conf/setup-environment

# create a workspace for a given recipe component
# recipe-component-name can be of:
# trusted-firmware-a / scp-firmware / u-boot / linux-arm64-ack
devtool modify <recipe-component-name>

# This creates a new workspace for recipe-component-name and fetches source code
# into "<tc0_workspace>/build-poky/workspace/sources/{trusted-firmware-a,scp-firmware,u-boot,linux-arm64-ack}"
# edit the source code in the newly created workspace
# build images with changes on workspace
# recipe-component-name can be of: trusted-firmware-a / scp-firmware / u-boot / linux-arm64-ack
bitbake <recipe-component-name>

Firmware Components 

Trusted Firmware-A 

Based on Trusted Firmware-A

Recipe	<tc0_workspace>/bsp/layers/meta-arm/meta-arm-bsp/recipes-bsp/trusted-firmware-a/trusted-firmware-a-tc0.inc
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/bl1-tc0.bin <tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/fip-tc0.bin

System Control Processor (SCP)

Based on SCP Firmware

Recipe	<tc0_workspace>/bsp/layers/meta-arm/meta-arm-bsp/recipes-bsp/scp-firmware/scp-firmware-tc0.inc
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/scp_ramfw.bin <tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/scp_romfw.bin

U-Boot 

Based on U-Boot gitlab

Recipe	<tc0_workspace>/bsp/layers/meta-arm/meta-arm-bsp/recipes-bsp/u-boot/u-boot-tc0.inc
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/u-boot.bin

Hafnium 

Based on Hafnium

Recipe	<tc0_workspace>/bsp/layers/meta-arm/meta-arm-bsp/recipes-bsp/hafnium/hafnium-tc0.inc
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/hafnium.bin

OP-TEE 

Based on OP-TEE

Recipe	<tc0_workspace>/bsp/layers/meta-arm/meta-arm-bsp/recipes-security/optee/optee-os-tc0.inc
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/optee/tee-pager_v2.bin

S-EL0 trusted-services 

Based on Trusted Services

Recipe	<tc0_workspace>/bsp/layers/meta-tc/recipes-security/trusted-services/secure-partitions_git.bb
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/firmware/crypto-sp.bin <tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/firmware/secure-storage.bin

Linux 

The recipe responsible for building a 5.10 version of the Android Common kernel (ACK).

Recipe	<tc0_workspace>/bsp/layers/meta-arm/meta-arm-bsp/recipes-kernel/linux/linux-arm-platforms.inc
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/Image

Distributions 

Poky Linux distro 

The layer is based on the poky Linux distribution. The provided distribution is based on BusyBox and built using glibc.

Recipe	<tc0_workspace>/bsp/layers/openembedded-core/meta/recipes-core/images/core-image-minimal.bb
Files	<tc0_workspace>/bsp/build-poky/tmp-poky/deploy/images/tc0/fitImage-core-image-minimal-tc0-tc0

Android 

Android Master (as on May21) is supported in this release with device profiles suitable for TC0 machine configuration. Android is built as a separate project and then booted with the BSP built by Yocto.

Run scripts 

Within the <tc0_workspace>/bsp/run-scripts/ are several convenience functions for testing the software stack. Usage descriptions for the various scripts are provided in the following sections.

Obtaining the TC0 FVP 

The TC0 FVP is available here for download.

Running the software on FVP 

A Fixed Virtual Platform (FVP) of the TC0 platform must be available to run the included run scripts.

The run-scripts structure is as follows:

run-scripts
|--tc0
   |--run_model.sh
   |-- ...

Ensure that all dependencies are met by running the FVP: ./path/to/FVP_TC0. You should see the FVP launch, presenting a graphical interface showing information about the current state of the FVP.

The run_model.sh script in <tc0_workspace>/bsp/run-scripts/tc0 will launch the FVP, providing the previously built images as arguments. Run the run_model.sh script:

./run_model.sh
Incorrect script use, call script as:
<path_to_run_model.sh> [OPTIONS]
OPTIONS:
-m, --model                      path to model
-d, --distro                     distro version, values supported [poky, android-nano, android-swr]
-a, --avb                        [OPTIONAL] avb boot, values supported [true, false], DEFAULT: false
-t, --tap-interface              [OPTIONAL] enable TAP interface
-e, --extra-model-params         [OPTIONAL] extra model parameters

Running Poky 

./run-scripts/tc0/run_model.sh -m <model binary path> -d poky

Running Android 

If using an android distro, export ANDROID_PRODUCT_OUT variable to point to android out directory
for eg. ANDROID_PRODUCT_OUT=<tc0_workspace>/android/out/target/product/tc0_swr

For running android with AVB disabled:
 ./run-scripts/tc0/run_model.sh -m <model binary path> -d android-swr
 OR
 ./run-scripts/tc0/run_model.sh -m <model binary path> -d android-nano

For running android with AVB enabled:
 ./run-scripts/tc0/run_model.sh -m <model binary path> -d android-swr -a true
 OR
 ./run-scripts/tc0/run_model.sh -m <model binary path> -d android-nano -a true

When the script is run, two terminal instances will be launched. terminal_s0 used for the SCP, TF-A, OP-TEE core logs and terminal_s1 used by TF-A early boot, Hafnium, U-boot and Linux.

Once the FVP is running, the SCP will be the first to boot, bringing the AP out of reset. The AP will start booting from its ROM and then proceed to boot Trusted Firmware-A, Hafnium, OP-TEE then U-Boot, and then Linux and Poky/Android.

When booting Poky the model will boot Linux and present a login prompt. Login using the username root. You may need to hit Enter for the prompt to appear.

The OP-TEE and Trusted Services are initialized on both the Android and Poky distribution. But the functionality of OP-TEE and core set of trusted services such as cryptography and secure storage can be invoked only on Poky distribution. For OP-TEE, the TEE sanity test suite can be run using command xtest. For Trusted Services, run command ts-service-test for Service API level tests and run command ts-demo for the demonstration client application.