NovaOS

NovaOS is a hobby operating system kernel written in Rust for the Raspberry Pi 3 B+. It is built as a learning project for low-level systems programming, bare-metal boot flow, and kernel development.

At A Glance

NovaOS currently includes:

• UART initialization and logging
• Delay and sleep primitives
• Exception level transitions across EL2, EL1, and EL0
• GPIO control and interrupt handling
• Peripheral mailbox communication
• Framebuffer drawing primitives
• Heap memory allocation
• MMU initialization and translation table setup

Work in progress:

• SVC instruction handling
• Basic UART console improvements
• Multi-application management

Planned next:

• Multi-core support
• Dynamic clock speed management
• Kernel-independent applications
• Multiprocessing improvements

Project Structure

• src/ - kernel source, architecture code, peripherals, interrupts, and runtime
• workspace/ - supporting crates such as heap and nova_error
• tools/ - build, simulation, SD image generation, and deployment scripts
• firmware_files/ - Raspberry Pi firmware files copied to SD or TFTP
• link.ld - linker script for the kernel image

Requirements

You will need:

• Rust nightly toolchain (rust-toolchain.toml pins nightly)
• Rust target aarch64-unknown-none
• llvm-objcopy for generating kernel8.img
• qemu-system-aarch64 for emulation
• mtools (mformat, mcopy) for SD image generation

Install the Rust target if needed:

rustup target add aarch64-unknown-none

Build

Debug image:

cd tools
./build_debug.sh

Release image:

cd tools
./build_release.sh

Both scripts produce a kernel8.img under target/aarch64-unknown-none/<profile>/.

Run In QEMU

1. Generate an SD image with firmware files:

cd tools
./generate_sd_card.sh

2. Start the emulator:

cd tools
./start_simulator.sh

For debug mode with the GDB stub enabled (-S -s):

cd tools
./start_simulator_debug.sh

Deploy To Hardware

Use the TFTP workflow to deploy to a Raspberry Pi:

1. Copy .env.example to .env and fill in your values:
   • REMOTE_USER
   • REMOTE_HOST
   • TFTP_PATH
   • BUILD_PATH
   • BINARY_NAME
   • KERNEL_NAME
2. Run:

cd tools
./deply_to_hw.sh

Notes

• This is an educational kernel project and is actively evolving.
• Interfaces and boot flow may change as features are added.