RPiOS Kernel (Early Version)

This is an early version of RPiOS kernel, which currently includes:

• A simple UART bootloader
• The kernel itself

The project is aimed at experimenting with bare-metal development on Raspberry Pi boards.

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⚙️ Features

Currently supported:

• UART bootloader for loading kernel images
• Basic memory management
• Multiple address spaces
• Round-robin scheduler
• Loading multiple binaries
• Simple syscall handler
• Basic drivers, including:
  • Interrupt controller
  • UART
  • Timer

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⚙️ Requirements

Make sure you have the ARM EABI toolchain installed with g++ support. In particular, we use the arm-none-eabi-* cross toolchain.

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🚀 How to Build and Run

1. Build UART Bootloader

cd ./uart_bootloader
./build.sh

This will produce a kernel.bin image. Copy it to the SD card boot partition and rename it as follows:

• kernel7.img for Raspberry Pi 2

When properly set up, the bootloader should output:

: Waiting for image data on UART

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2. Build Kernel

cd ./kernel
./build.sh

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3. Send Kernel via UART

Use the send.sh script to communicate with the UART bootloader and upload the kernel:

./send.sh /dev/ttyUSB0

Expected output:

: Waiting for image data on UART
: Data transfer detected, downloading the image ...
: Image size (bytes): 4324

: Data transfer finished, giving up control to kernel

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📌 Notes

• Supports basic multitasking and system calls.
• Currently only basic UART bootloading and kernel execution are supported.
• This is an early stage project
• Tested on Raspberry Pi 2B.

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📄 License

This project is released under the MIT License.