C/C++ Raspberry Pi 4B Kernel

Features

• Developed on bare metal for Raspberry PI4 B with Cortex A72 (ARM v8.A)
• Premptive Multitasking
• Interrupts (GIC400)
• Multicore
• Virtual memory & MMU
• Buddy Allocator
• Synchronization (ARM Spinlock)
• UART RX/TX
• Videocore VI Mailbox Interface
• Framebuffer (HDMI output)

Debug & Testing

Debugged on live hardware with OpenOCD + JTAGS + Olimex Tiny H (https://www.olimex.com/Products/ARM/JTAG/ARM-USB-TINY-H/)

Install openocd from sources with

./configure --enable-ftdi

I/O Through MiniUART to USB with minicom

sudo minicom -D /dev/ttyUSB0 --baudrate 11520

Debugging with minicom and GDB

Live Demo

The color of every circle gets determined by which core is running the relative rendering task

Running on 4 cores with parallel rendering and 2000 Drawing Tasks scheduled dynamically on the most available core

video_2023-03-14_17-59-56.1.webm

TODO:

• Unix Pipes
• System calls
• Shell
• Users, Groups & Permissions
• EMMC Driver
• Custom filesystem
• ELF Loader
• Slab Allocator
• On Disk Paging
• Usermode Tasks
• Networking (Ethernet, ARP, UDP, DHCP)
• USB Driver
• (...)

[Work in progres...]