🌱 KrcyOS

A toy RISC-V kernel built with Zig for OS exploration.

Current

• Booting: Clean RISC-V boot process over OpenSBI.
• Console: Formatted serial output via SBI calls.
• Power: Shutdown for both QEMU and bare-metal.
• Logging: Multiple terminal log printing methods.
• Panic: Panic triggered under exceptions or manually.
• Trap: Exception table with dynamic instruction length decoding.
• Pmm: Dynamic physical page allocation via intrusive free list.
• Vmm: Sv39 reality bending with mapping and kernel protection.

Motivation

Just to understand OS.

Prerequisites

• Zig (>=0.16.0)
• QEMU (>=11.0.0, if you don't have a real board)
• Only (task runner if you like)

Didn't check it yourself before asking? RTFM first.

Getting Started

Clone the toy

git clone https://codeberg.org/Kercy/krcyos.git
# if you prefer github:
# git clone https://github.com/KercyDing/krcyos.git
cd krcyos
# ...

Simply run it

zig build run -Dboard=qemu_virt
# or:
# only run qemu

If you have a real board:

zig build run -Dboard=real_board
# or:
# only run real

Then flash to your board.

Try another log level? You can:

zig build run -Dboard=qemu_virt -Dlog=info
# or:
# only run qemu info

That's it. Should be a piece of cake.

Why not Rust?

Simply put, I prefer Zig over Rust.

For me, Rust isn't explicit enough at the kernel level, even though 90% of my projects are written in Rust :)