system

A hobby multikernel inspired by Barrelfish¹ and seL4². It only supports x86_64 QEMU at the moment.

Project Layout

This project is loosely based on the Pitchfork Layout:

• apps/: user-mode programs that can be run by the operating system. Each subdirectory contains an individual application, which may be linked against one or more libraries.
• build/: not checked into the repository, but generated at build-time. Contains intermediate artifacts and final binaries, as well as the ISO file to launch QEMU with.
• docs/: contains datasheets, technical documentation, and generated Doxygen documentation.
• drivers/: generally user-mode programs which interface with the core driver for the current architecture in order to manage a specific hardware device via system calls. This directory also contains the architecture-specific core drivers, which run in supervisor mode. Each subdirectory contains one or more drivers; for example, the drivers/core directory contains a subdirectory with a driver for each supported processor architecture.
• libs/: static libraries that apps or drivers can link against and use. Each subdirectory contains an individual library.
• tests/: contains the run.sh test script for running QEMU.
• tools/: contains the build/test environment configure script, Dockerfile, and Doxygen configuration file.

Environment

The tools/Dockerfile defines a complete build and test environment in a Debian-stable Docker container. The container has the following software installed, which is required to build and test the OS:

• clang++ 13.0.0 or newer
• Doxygen 1.9.1 or newer
• GDB 10.1.90.20210103-git or newer
• Git 2.30.2 or newer
• Graphviz 2.42.2-5 or newer
• Grub-common 2.04-20 or newer
• Grub-pc-bin 2.04-20 or newer
• less 551 or newer
• Meson 0.59.1 or newer
• nasm 2.15.05 or newer
• Ninja 1.10.2 or newer
• Pip 20.3.4 or newer
• Python 3.9.2 or newer
• QEMU 5.2.0 or newer
• Xorriso 1.5.2 or newer

Building

Normal debug build:

> meson build/ --buildtype debug --cross-file x64.ini
> ninja -C build/

Release build:

> meson build/ --buildtype release --cross-file x64.ini
> ninja -C build/

Generating Doxygen documentation (output to docs/doxygen):

> meson build/ --cross-file x64.ini
> ninja -C build/ docs

Running

Running QEMU with standard options and serial port output:

> tests/run.sh

Running QEMU with interrupt debugging turned on and logged to ~/qemu.log:

> tests/run.sh --debug

Running QEMU with interrupt debugging turned on and logged to ~/qemu.log, and GDB remote debugging:

> tests/run.sh --gdb
> gdb -q
(gdb) source src/debug/gdb_pre_script
(gdb) continue

NOTE: GDB remote debugging will pause on startup. When you connect to QEMU via GDB, issue a continue at the GDB prompt to continue.

1: The Barrelfish Operating System
2: The seL4 Microkernel