Building L4Re on MacOS

Building L4Re on MacOS#

L4Re can also be build on MacOS. The tools the L4Re build system relies on are available via Homebrew, an open source software distribution and package manager for MacOS.

So first, you need to install Homebrew on your Mac. Ensure that Homebrew is hooked up into your PATH as suggested by Homebrew.

Then proceed to install the following packages needed to build L4Re:

brew install make bash gawk aarch64-elf-binutils aarch64-elf-gcc dialog findutils coreutils u-boot-tools gnu-sed qemu dtc wget

Note that not all packages are mandatory, however, the list presents a useful set of packages.

Ham#

Ham is a tool that manages multiple Git repositories from a common manifest file. Ham is used by the L4Re infrastructure. It is optional. Git repositories can be also downloaded with Git alone given they are arranged as required.

Ham is available for download.

See below for instructions how Ham can be used from its source repository on MacOS.

Proceeding with Building L4Re#

Now your MacOS system should be ready to build L4Re for Aarch64/arm64 targets. However, for doing so, use gmake instead of make, and use CROSS_COMPILE=aarch64-elf-.

Other targets (such as x86) are not supported because that would require a gcc cross-compiler to be available in Homebrew. As LLVM/clang can also be used to compile L4Re, the LLVM package from Homebrew should also work with all the targets it has built in. This guide shall be extended with this possibility.

You can proceed now with the normal L4Re build process, obeying the two rules just mentioned. Please follow Building With GNU Make.

For convenience, here’s a quick guide for an Aarch64 build:

Building L4Re from source for Aarch64#

Go to a directory of your choice, such as ~/src/l4re, and do:

ham init -u https://github.com/kernkonzept/manifest.git
ham sync

Set up some configuration. Can be any, given it is built for Aarch64.

cat << _EOF > l4/defconfig
CONFIG_BUILD_ARCH_arm64=y
_EOF

cat << _EOF > fiasco/defconfig
CONFIG_ARM=y
CONFIG_ARM_CORTEX_A57=y
CONFIG_MP_MAX_CPUS=8
CONFIG_ARM_SMC_USER=y
CONFIG_ARM_PSCI=y
CONFIG_PERFORMANCE=y
CONFIG_PERF_CNT_USER=y
CONFIG_EXPERT=y
_EOF

Now build, by creating a build directory for both the L4Re user-level and the microkernel, and building each:

gmake -j $(nproc) -C l4 B=$PWD/l4-build CROSS_COMPILE=aarch64-elf- DEFCONFIG=defconfig
gmake -j $(nproc) -C l4-build CROSS_COMPILE=aarch64-elf-

cp l4/conf/Makeconf.boot.example l4/conf/Makeconf.boot

gmake -j$(nproc) -C fiasco B=$PWD/fiasco-build-arm64 DEFCONFIG=defconfig CROSS_COMPILE=aarch64-elf-
gmake -j$(nproc) -C fiasco-build-arm64 CROSS_COMPILE=aarch64-elf-

If that’s done, you could use QEMU to run it:

gmake -C l4-build CROSS_COMPILE=aarch64-elf- elfimage E=hello PT=arm_virt \
       MODULE_SEARCH_PATH=$PWD/fiasco-build-arm64

l4/tool/bin/l4image -i l4-build/images/bootstrap.elf launch

Optional: Using Ham from its source repository#

In case you want to use Ham from its source repository on MacOS, some prerequisites have to be fulfilled.

Ham is writte in Perl and uses some further Perl modules, which need to be installed: Git::Repository and XML::Parser.

cpan install Git::Repository XML::Parser

This shall work with both the Perl that comes with MacOS as well as the (more recent) Perl from Homebrew.

Then, get the Ham tool:

git clone https://github.com/kernkonzept/ham.git

Make sure to include the ham directory in your PATH or link the ham binary to some location in your PATH.

Calling ham without arguments shall present a help text.

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