Core files for the Xous microkernel operating system.
This repository contains everything necessary to build the Xous kernel from source. It consists of the following projects:
- kernel: core memory manager, irq manager, and syscallhandler
- loader: initial loader used to start the kernel
- tools: programs used to construct a final boot image
- docs: documentation on various aspects of Xous
- emulation: Renode scripts used to emulate Xous
- xous-rs: userspace library
- Xous requires its own Rust target,
riscv32imac-unknown-xous-elf. If you run
cargo xtaskfrom the command line, you should be prompted to install the target automatically if it does not already exist.
- You may need to remove the
target/directory before building, if
rustccontinues to behave like it can't find the
xoustarget even after it is installed.
- If you plan on doing USB firmware updates, you'll need
pyusb(updates). Note that
pyusbhas name space conflicts with similarly named packages, so if updates aren't working you may need to create a
venvor uninstall conflicting packages.
- If you are doing development on the digital signatures with the Python helper scripts, you will need:
pycryptodome(signing - PEM read),
cryptography(signing - x509 read),
pynacl(signing - ed25519 signatures) (most users won't need this).
- Some system packages are needed, which can be installed with
sudo apt install libssl-dev libxkbcommon-devor similar
- If you receive an error about
feature resolver is required, try installing a newer version of
Quickstart using Hosted Mode
You can try out Xous in a "hosted mode" wherein programs are compiled for your native platform and are run locally as processes within your current operating system. System calls are replaced with network calls to a kernel that simply shuffles messages around.
Xous uses the xtask convention,
where various complex build commands are stored under
This allows for us to create arbitrarily complex build sequences
without resorting to
make (which is platform-dependent),
sh (which requires a lot of external tooling), or another build
To build a set of sample programs and run them all using the kernel for communication, clone this repository and run:
cargo xtask run
This will build several servers and a "shell" program to control them
all. Most notably, a
graphics-server will appear and kernel messages
will begin scrolling in your terminal.
Quickstart using an emulator
Xous uses Renode as the preferred emulator, because it is easy to extend the hardware peripherals without recompiling the entire emulator.
Then, build Xous:
cargo xtask renode-image
This will compile everything in
release mode for RISC-V, compile the tools
require to package it all up, then create an image file.
Finally, run Renode and specify the
xous-release.resc REnode SCript:
Renode will start emulation automatically, and will run the same set of programs as in "Hosted mode".
Generating a hardware image
To build for real hardware, you must specify an
.svd file. This
file is generated by the SoC build process and describes a single
Betrusted core. These addresses will change as hardware is modified,
so if you distribute a modified Betrusted core, you should be sure
to distribute the
We have included a reference version of the gateware and its SVD
file in the
precursors directory, so you can compile a gateware
for the reference image using this command:
cargo xtask hw-image precursors/soc.svd
The resulting images are in your target directory (typically
with the names
xous.img (for the kernel) and
loader.bin (for its bootloader). The corresponding
gateware is in
precursors/soc_csr.bin. These can be written to your
device by following the update guide.