Getting Started #

To get to the point whre you can do anything with LionsOS you need to set up a system with toolchain, the LionsOS components, and the microkit tools.

This section describes how to do that. It assumes a Debian-like host (Debian, Ubuntu, Mint, etc). If you have instructions for a RedHat derived build system (RedHat, Fedora, CentOS etc), Suse, or ArchLinux, please generate a pull request against https://github.com/au-ts/lionsos-docs

ToolChain #

You need a toolchain for your target platform. LionsOS is for embedded systems wih a static architecture; it is currently available only for AARCH64.

The recommended toolchain is from ARM Toolchains We’re currently using the 12.3 version.

wget 'https://developer.arm.com/-/media/Files/downloads/gnu/12.3.rel1/binrel/arm-gnu-toolchain-12.3.rel1-x86_64-aarch64-none-elf.tar.xz?rev=a8bbb76353aa44a69ce6b11fd560142d&hash=20124930455F791137DDEA1F0AF79B10' \
    -O arm-gnu-toolchain-12.3.rel1-x86_64-aarch64-none-elf.tar.xz
tar xf arm-gnu-toolchain-12.3.rel1-x86_64-aarch64-none-elf.tar.xz

I usually put the toolchain in /opt/toolchain, then add it to my PATH thus:

export PATH=/usr/lib/ccache:/opt/toolchain/arm-gnu-toolchain-12.3.rel1-x86_64-aarch64-none-elf/bin/:$PATH

then add symlinks into /usr/lib/ccache thus:

$ cd /usr/lib/ccache
$ sudo ln -s ../../bin/ccache aarch64-linux-gnu-gcc
$ sudo ln -s ../../bin/ccache aarch64-linux-gnu-g++

This allows using ccache to speed repeat builds. You can create symlinks for any other C and C++ compilers you want to use; Debian puts links there for compilers installed using apt.

The Microkit #

For some of the tutorials you will be building the Microkit. However, prebuilt versions are available from the Trustworthy Systems Download pages; individual tutorials will tell you the URL to use to fetch the right version for that tutorial.

The microkit is available from its Github repository. Its ReadME gives instructions for building. Some tutorials use experimental versions of the microkit; they will tell you which one to pull and build

During the Microkit build process, it also builds an instance of the seL4 microkernel for each targeted platform. You can fetch seL4 from its [Github repository]{https://github.com/seL4/seL4), using the microkit branch until that gets merged. Particular tutorials may need a different version of seL4; these will give instructions.

LionsOS #

LionsOS consists of libraries and components for building complete systems. To get it, clone its Github Repository and then update its submodules (this is around 1.7Gb):

git clone git@github.com:au-ts/lionsos.git
cd lionsos
git submodule update --init

Environment Variables #

To save typing, the build system uses some environment variables to track where things go:

LionsOSPathname to top of LionsOS TreeTo find LionsOS components
MICROKIT_SDKPathname to the MicrokitTo find board descriptions, etc
PATHWhere to find executablesMake sure compilers and ${MICROKIT_SDK}/bin are in the PATH