swift_os

An operating system written in Swift.

Modules

• Boot — Minimal boot code before entering Swift.
• Kernel — Kernel executable and system entry point.
• KernelCore — Architecture- and platform-independent kernel logic (scheduler, memory management, core services).
• Hardware — Hardware abstraction layer defining device interfaces independent of CPU architecture and platform (console, timer, framebuffer, etc.).
• CPU architecture support
  • ArchAArch64 - AArch64 CPU support (exceptions, MMU, vector tables, system registers).
  • ArchX8664 - (planned) x86_64 CPU support (IDT, paging, interrupts).
• Platform support
  • RaspberryPi — Raspberry Pi platform implementation (UART, mailbox, framebuffer, interrupt controller).
• KernLibc — Minimal libc for kernel space.
• AppLibc — Minimal libc for user space.
• AsmSupport — Assembly helper functions.
• LinkerSupport — Swift bindings for linker-defined symbols.

Prerequisites

• QEMU 9.0 or later
  • Arch Linux: sudo pacman -S qemu-system-aarch64
  • Fedora 41 or later: sudo dnf install qemu-system-aarch64-core
  • Fedora 40: Build from source
  • Ubuntu 24.04/22.04: Build from source
  • Debian 13 or later: run0 apt install qemu-system-arm
  • Debian 12: sudo apt install -t bookwarm-backports qemu-system-arm (you need to add backports to sources.list)
  • macOS 14 or later: brew install qemu
• Swiftly
• Swift toolchain: Just run swiftly install after installing Swiftly

Building

swift build --triple aarch64-none-none-elf --toolset toolset.json --build-system native

.build/debug/Kernel is the kernel binary.

Running on QEMU

swift run --triple aarch64-none-none-elf --toolset toolset.json --build-system native

Running on Raspberry Pi 4

Debug build (recommended for development):

swift build --triple aarch64-none-none-elf --toolset toolset.json --build-system native
llvm-objcopy .build/debug/Kernel -O binary .build/kernel8.img

Warning

Known issue: #167

Release build (recommended for deployment):

swift build -c release -Xswiftc -Osize --triple aarch64-none-none-elf --toolset toolset.json --build-system native
llvm-objcopy .build/release/Kernel -O binary .build/kernel8.img

How to boot:

1. Build .build/kernel8.img following the above instructions
2. Read this article and prepare a bootable SD card
3. Replace kernel8.img on the SD card with .build/kernel8.img you built
4. Insert the SD card to your Raspberry Pi 4
5. Turn the power on

Cleaning build outputs

swift package clean

swift-format

This project is using swift-format for formatting and linting.

Format:

swift format format -rip .

Lint:

swift format lint -rsp .