Bazzulto OS

Bazzulto is an AArch64 operating system built from scratch in Rust, designed with professional standards: correct boot assumptions, documented hardware contracts, and well-defined subsystem boundaries.

Architecture

QEMU virt  →  UEFI (edk2)  →  Limine  →  bazzulto.elf (Rust kernel)
                                              ↓
                                         bzinit (PID 1, service manager)
                                              ↓
                                     bzsh / bzdisplayd / drivers …

The kernel is pure Rust (kernel/). All userspace — including the init system, shell, display server, and utilities — is also Rust (userspace/bin/), built against the Bazzulto Standard Library (userspace/lib/bsl/).

Features

• UEFI boot via Limine — no BIOS, no legacy hardware
• Pure Rust kernel — AArch64 EL1, no C
• ELF64 loader with ASLR, guard pages, and 8 MiB user stacks
• vDSO — syscall numbers are never baked into compiled binaries
• VFS — ramfs, FAT32, tmpfs, devfs, procfs
• Slab allocator — 10 power-of-two size classes, 64 KB arenas
• Round-robin scheduler with 32 768 PID slots
• bzinit — dependency-ordered service manager (PID 1)
• bzsh — interactive shell
• bzdisplayd — userspace display server via framebuffer

Building

Prerequisites:

• aarch64-elf-gcc / aarch64-elf-ld (cross toolchain)
• Rust nightly with aarch64-unknown-none target
• QEMU (qemu-system-aarch64) with edk2-aarch64-code.fd
• Python 3 (for create_disk.py)

# Full build (BSL release + kernel debug)
make

# Run in QEMU
make run

# Release build + run
make run-release

# Build a single userspace crate
make bsl-crate CRATE=bzinit

# Clean everything
make clean

Project layout

kernel/          Rust kernel source
userspace/
  bin/           Rust userspace workspace (bzinit, bzsh, bzctl, …)
  lib/bsl/       Bazzulto Standard Library
    Bazzulto.System/   syscall wrappers, global allocator, vDSO
    Bazzulto.IO/       file, path, stream abstractions
  libraries/
    libc/        POSIX C library headers (stubs) + musl submodule
  services/      TOML service definition files
  fonts/         Embedded fonts
esp/             UEFI boot partition (EFI + Limine config)
docs/            References and internal wiki

Third-party components

musl libc

Bazzulto includes musl as a git submodule at userspace/libraries/libc/musl/.

musl is an MIT-licensed implementation of the standard C library written by Rich Felker and contributors. It targets the Linux syscall API; the Bazzulto port replaces arch/aarch64/bits/syscall.h.in with Bazzulto syscall numbers while keeping the rest of musl unchanged.

• Homepage: https://musl.libc.org/
• Repository: https://git.musl-libc.org/cgit/musl
• License: MIT — see userspace/libraries/libc/musl/COPYRIGHT

License

MIT — see LICENSE.

Contributing

See CONTRIBUTING.md.