A fully from scratch operating system the QEMU ARM "virt" machine and the Raspberry Pi Zero. Still need to find a good name for it.
There's barely a GUI or any usable software, but you can run DOOM:
The easiest way to try it out is to install qemu-system-arm, download a package
from the CI pipeline and run the script inside it.
That will start a QEMU instance setup with peripherals and a disk image with all
the available programs for you to play with.
There is a Docker image that can be used to build the project.
You cannot use it to run QEMU though, so you'll have to install qemu-system-arm
separately outside of it, and also make.
To build using Docker, run the following commands:
docker build -t pi0-os .
docker run -v $(pwd):/pi0-os pi0-os
This will build the kernel, all of the userland programs and automatically create a disk image.
Running make qemu will start the QEMU instance using the built kernel
and disk image.
Here's a useful .gdbinit, add it to your kernel/ directory.
target remote localhost:1234
file kernel.elf
add-symbol-file boot/boot.elf
make qemu-gdb will start QEMU with the GDB stub enabled and paused.
On another terminal, run gdb-multiarch inside the kernel/ directory
and it will automatically attach to the running QEMU instance and load
the symbols file for both the kernel and the bootloader.
RECORD=1 make qemu will record the execution of QEMU.
REPLAY=1 make qemu-gdb will replay the recorded execution