AvoryOS

AvoryOS

An open-source monolithic hobby operating system kernel for the x86_64 architecture.

AvoryOS is built from scratch in C and Assembly. It features a Linux-compatible system call interface, POSIX userland compatibility, dual musl and glibc runtimes, native in-kernel IPv4 & IPv6 networking, and a LinuxKPI compatibility layer for upstream graphics drivers.

The system boots using the Limine bootloader protocol (UEFI & BIOS), supports both 4-level and 5-level paging, and runs desktop environments including KDE Plasma 6, XFCE4, and IceWM inside QEMU and on real hardware.

GitHub Repository Rewrite Branch Build Instructions

Screenshots

Captures from recent builds running in QEMU with KVM acceleration:

AvoryOS running KDE Plasma 6
KDE Plasma 6 on AvoryOS — Welcome Center, Konqi mascot, and application menu.
AvoryOS 2.5.0 Beta running XFCE and Minecraft 1.16.5
AvoryOS 2.5.0 Beta — XFCE 4.18 desktop running Minecraft Java Edition 1.16.5 via OpenJDK 17 and LWJGL.

Kernel Highlights

Core & Memory Subsystem

  • Architecture: 64-bit higher-half kernel booted via the Limine protocol.
  • PMM: Physical Memory Manager with per-CPU page caches and NUMA/node awareness.
  • VMM: Virtual Memory Manager with 4-level paging, PCID hardware tagging, hugepages, copy-on-write (COW), demand paging, and batched TLB shootdowns.
  • Scheduler: Preemptive SMP scheduler with multi-core APIC/IPI support, POSIX threads, futexes (with priority inheritance), and signals.
  • Syscall Engine: Fast syscall handling (syscall/sysret), user access optimizations (fast_copy_user), and vDSO page.

Virtual Filesystem (VFS)

  • VFS with page cache and dentry cache.
  • EXT4 & EXT2: Native read/write support.
  • FAT32: Support for EFI partitions and USB storage.
  • Pseudo-filesystems: RamFS, TmpFS, DevTmpFS, ProcFS (/proc), and SysFS (/sys).

Networking (IPv4 & IPv6)

  • In-kernel network core with a dedicated asynchronous worker thread.
  • Dual-stack IPv4 and IPv6 support with Neighbor Discovery (NDP), ICMPv6, and SLAAC autoconfiguration.
  • BSD socket API layer (AF_INET and AF_INET6 UDP/TCP sockets).
  • Realtek RTL8139 NIC driver with SysFS device registration.

Hardware & Driver Support

Storage & Partitioning

  • NVMe: PCIe Gen3/Gen4/Gen5 driver with namespace discovery and command queueing.
  • GPT: Full GUID Partition Table partitioning support alongside legacy MBR.
  • SATA / IDE: AHCI (SATA) and legacy IDE/ATA controllers.
  • Ramdisk: Limine module embedded ramdisk boot.

Graphics & LinuxKPI

  • Native ascentdrm: Framebuffer and VirtIO-GPU DRM backend with hardware cursor management.
  • LinuxKPI Subsystem: Compatibility layer designed to run unmodified upstream Linux kernel drivers (PCIe VFIO passthrough, DRM/TTM/dma-buf).
  • AMDGPU: Hardware bring-up and mode-setting pipeline (experimental/WIP).
  • Mesa Acceleration: llvmpipe / pixman software rasterizers and Gallium drivers.

Audio & Input

  • Audio: Intel High Definition Audio (HDA), AC'97, and Sound Blaster 16 (/dev/dsp).
  • Evdev Layer: Unified input subsystem for PS/2 keyboards/mice and USB HID devices.
  • USB Controllers: xHCI, EHCI, OHCI, and UHCI.

Userland Ecosystem

AvoryOS combines custom software with standard Linux userland packages through Alpine Linux integration and dual C runtimes:

Category Software & Packages
Toolchains GCC, G++, GNU Binutils, Make, Tiny C Compiler (TCC), musl libc, GNU glibc
Desktops KDE Plasma 6, XFCE 4.18, IceWM, AetherDE (AetherWM, Dock & Panel), Weston (Wayland), Xorg Server
Games Minecraft Java Edition 1.16.5 (OpenJDK 17 + LWJGL), Mocktail (Roblox), Yamagi Quake II, DOOM, ClassiCube, Butterscotch
Applications Mozilla Firefox, VLC media player, GNU Coreutils, Bash 5.3, cmus, fastfetch, kilo editor, Kria

Building from Source

Building requires a 64-bit Linux host (Ubuntu/Debian, Arch, Fedora, etc.).

1. Install Dependencies

sudo apt install make gcc nasm git curl xorriso \
    qemu-system-x86_64 e2fsprogs bison flex util-linux parted

2. Clone & Bootstrap

git clone -b Rewrite https://github.com/Hidotu-Labs/AvoryOS.git
cd AvoryOS
./bootstrap.sh

3. Setup Alpine Userland

./scripts/setup-alpine.sh

4. Compile Kernel & Disk Image

make

5. Run in QEMU

Launch with KVM acceleration, NVMe root disk, and VirtIO graphics:

make run

Or run with software TCG emulation if KVM is unavailable:

make run-tcg