KO | EN

GitLite

Minimalist Open Source Repository Search Engine

gitlite — search

#dsh #dsh-plugin #deepseek-harness #typescript #ai-agent #codex #developer-tools #claude-code #windows #mcp #python #desktop-app

StelluxOS

★ 59 Open GitHub ↗

Stellux operating system is my research operating system project inspired by Symbiote's philosophy of providing runtime privilege level switching for userspace threads.

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

<div align="center">
  <img src="screenshots/usb_stick_logo.jpg" alt="Stellux OS" width="200" />
  <h1>Stellux OS</h1>
  <p>
    A research operating system exploring runtime privilege transitions for kernel threads.
  </p>
  <p>
    <a href="https://github.com/FlareCoding/StelluxOS/actions/workflows/kernel-unit-tests.yml">
      <img src="https://github.com/FlareCoding/StelluxOS/actions/workflows/kernel-unit-tests.yml/badge.svg" alt="Kernel CI" />
    </a>
    <a href="https://github.com/FlareCoding/StelluxOS/graphs/contributors">
      <img src="https://img.shields.io/github/contributors/FlareCoding/StelluxOS" alt="contributors" />
    </a>
    <a href="https://github.com/FlareCoding/StelluxOS/stargazers">
      <img src="https://img.shields.io/github/stars/FlareCoding/StelluxOS" alt="stars" />
    </a>
    <a href="https://github.com/FlareCoding/StelluxOS/blob/master/LICENSE">
      <img src="https://img.shields.io/github/license/FlareCoding/StelluxOS.svg" alt="license" />
    </a>
  </p>
</div>

## Overview

<p>
StelluxOS is a personal operating system project inspired by <a href="https://github.com/Symbi-OS/">Symbiote</a> project's philosophy of providing runtime privilege
level switching mechanism for userspace threads. The unique feature of StelluxOS is that within the authoritative OS-level
privileged domain, threads can transition in and out of hardware privilege at a very low cost using lightweight primitives
called <b>elevate</b> and <b>lower</b>. This use of dynamic privilege would allow deprivileging large parts of the kernel
and allow threads within the "<i>blessed</i>" kernel address space to acquire privilege when needed, performing privileged operations,
and dropping hardware privileges right after.
</p>
<p>
The benefit of this design that we aim to explore is that, for example, if a driver or a filesystem component
has a memory corruption bug and causes a stray write that would overwrite a bit in some page table entry, in a regular
monolithic kernel this might not show any problematic symptoms until later down the line, however in Stellux, if an unprivileged
driver makes such a stray write into a privileged region or data structure, it would cause a page fault with a nice backtrace
showcasing what happened right there and then when it actually happened.
</p>
<p>
Additionally, this design might bring a new perspective on how privilege is viewed, used, and leveraged in userspace
applications, potentially offering new design spaces that we are yet to explore. <b>It is important to note</b>, the goal
of StelluxOS is <b>NOT</b> to replace an existing design or claim that this one is better, but rather explore a new point
in the design space and potentially offer a new avenue for operating system research.
</p>

### Research Basis

The design and motivation behind StelluxOS are described in my SOSP 2024 poster:

## Screenshots

## Supported Platforms

| Architecture | Platform | Status | Hardware Tested |
|---|---|---|---|
| x86_64 | Generic UEFI | Fully supported | Yes (RTL8168 NIC, PCIe serial, xHCI USB) |
| AArch64 | QEMU virt | Fully supported | QEMU |
| AArch64 | Raspberry Pi 4 (BCM2711) | Supported | Yes |

The kernel boots via the [Limine](https://github.com/limine-bootloader/limine)
UEFI boot protocol on all platforms. The RPi4 target uses UEFI firmware from
the [pftf/RPi4](https://github.com/pftf/RPi4) project.

## Getting Started

### Prerequisites

Linux (Debian/Ubuntu) and macOS are both supported development
environments, with the same commands on either OS. The kernel is built
with Clang/LLD; userland applications link against a statically-built
musl libc.

Clone the repository and run the one-time setup:

```
git clone https://github.com/FlareCoding/StelluxOS.git
cd StelluxOS
make deps
make limine
make musl
make libcxx
make compiler-rt
```

`make deps` installs system packages -- via apt on Linux (clang, lld,
llvm, qemu, ovmf, mtools, etc.) and via [Homebrew](https://brew.sh) on
macOS (llvm, lld, qemu, mtools, gptfdisk, etc.). `make limine` downloads
the Limine bootloader binaries. `make musl` builds musl 1.2.5 for both
x86_64 and aarch64. `make libcxx` builds the LLVM C++ runtime (libc++,
libc++abi, libunwind) against the musl sysroot for C++ userland
application support. `make compiler-rt` builds the compiler runtime
builtins for both architectures.

The optional CPython userland app additionally requires a host
`python3.12` (e.g. `brew install python@3.12` / `apt install python3.12`).

Run `make toolchain-check` to verify everything is in place.

For RPi4 support, also run:

```
make rpi4-firmware
```

### Building

All build and run targets require an `ARCH` parameter (`x86_64` or `aarch64`).

```
make image ARCH=x86_64          # Build kernel + userland + disk image
make image ARCH=aarch64         # Same for AArch64
```

Shortcut targets that do not require `ARCH`:

```
make image-x86_64
make image-aarch64
```

### Running in QEMU

```
make run ARCH=x86_64             # QEMU with graphical window
make run-headless ARCH=x86_64    # Headless (serial on stdio, useful over SSH)
```

### Running Unit Tests

```
make test ARCH=x86_64
make test ARCH=aarch64
```

### Debugging with GDB

In one terminal, start QEMU with the GDB stub:

```
make run-qemu-x86_64-debug-headless
```

In another terminal, connect GDB:

```
make connect-gdb-x86_64
```

The same pattern applies for AArch64 (`run-qemu-aarch64-debug-headless`,
`connect-gdb-aarch64`). On AArch64, the Makefile uses `gdb-multiarch`
where available (Linux) and multi-target `gdb` otherwise (macOS).

### Baremetal Debugging

StelluxOS includes a GDB server stub that can operate over a PCIe serial
controller on real hardware. Add `enable-gdb-stub` to the GRUB/Limine kernel
command line arguments, then connect from a second machine watching the serial
port. You may need to adjust the serial TTY device in the connect target.

### USB Boot

```
make usb ARCH=x86_64
```

This builds the image and prints instructions for writing it to a USB drive
with `dd`.

### Build Options

| Option | Description |
|---|---|
| `V=1` | Verbose output (show compiler commands) |
| `RELEASE=1` | Release build (O2 optimization) |
| `DEBUG=1` | Debug build (default) |

## Reference Specifications

The `specs/` directory contains reference documents used during development:

- [specs/stellux.pdf](specs/stellux.pdf) -- Stellux project poster
- [specs/64-ia-32-architectures-software-developer-vol-3a-part-1-manual.pdf](specs/64-ia-32-architectures-software-developer-vol-3a-part-1-manual.pdf) -- Intel SDM Vol. 3A
- [specs/extensible-host-controler-interface-usb-xhci.pdf](specs/extensible-host-controler-interface-usb-xhci.pdf) -- xHCI specification
- [specs/USB 3.2 Revision 1.1.pdf](specs/USB%203.2%20Revision%201.1.pdf) -- USB 3.2 specification

## Contributing

Contributions are welcome through pull requests.

## License

[MIT](https://opensource.org/licenses/MIT)

## Acknowledgements

This work was supported by the Red Hat Collaboratory at Boston University under
the award "Symbiotes: A New Step in Linux's Evolution", Red Hat Collaboratory
Research Incubation Award Program (2024-01-RH12).

Special thanks to Dr. Tommy Unger for the Symbiote and kElevate work, and
Dr. Jonathan Appavoo for supporting this project from inception.

StelluxOS

Explore Similar Repositories

Was this content helpful?

Recent Feedback

Download README