FKernel

A small hybrid kernel for x86_64 with a freestanding, bare-metal focus. It is inspired by MINIX, seL4, Mach, the BSDs, and SerenityOS.

Highlights

• Hybrid kernel design, influenced by MINIX, seL4, Mach, the BSDs, and SerenityOS
• Runs directly on hardware (bare-metal), written in modern C++20 without the usual C++ runtime
• Boots with GRUB using the Multiboot2 standard
• Target platform: x86_64 PCs (for now)
• Includes early boot, basic memory management, a simple virtual file system, and essential drivers (timer, interrupts, serial port, ATA disk)

Prerequisites

Build host: Linux (x86_64 recommended)

Required tools:

• Toolchain: clang/clang++ (C++20), ld.lld
• Assembler: nasm
• Build system: xmake
• Boot image tooling: grub-mkrescue (or grub2-mkrescue), plus xorriso and mtools
• Emulator: qemu-system-x86_64 (and qemu-img)

Notes:

• Some distros ship grub2-mkrescue instead of grub-mkrescue.
• grub-mkrescue typically requires xorriso and mtools packages.

Linux

Follow the steps for your distro, then build and run.

1. Install dependencies

• Debian/Ubuntu:

  sudo apt update
  sudo apt install -y \
    clang lld nasm xmake \
    qemu-system-x86 qemu-utils \
    grub-pc-bin grub-common \
    xorriso mtools \
    jq clang-format clang-tidy cppcheck

• Arch Linux:

  sudo pacman -Syu --needed \
    clang lld nasm xmake \
    qemu grub xorriso mtools \
    jq clang-format clang-tidy cppcheck

• Fedora:

  sudo dnf install -y \
    clang lld nasm xmake \
    qemu-system-x86 qemu-img \
    grub2-tools-extra xorriso mtools \
    jq clang-tools-extra cppcheck

2. Get the code

git clone https://github.com/KitsuneBSD/FKernel.git
cd FKernel

3. Build, run, clean

xmake          # build
xmake run      # launch QEMU with the generated ISO
# (quit QEMU with Ctrl+A, X if using the QEMU monitor on stdio)
xmake clean    # remove build artifacts

Artifacts created:

• Kernel: build/FKernel.bin
• ISO: build/FKernel-MockOS.iso
• Disk (qcow2): build/FKernel-HDA.qcow2

If ISO creation fails, ensure GRUB i386-pc modules are installed (e.g., grub-pc-bin on Debian/Ubuntu) and the path /usr/lib/grub/i386-pc/ exists, or adjust Meta/mounting_mockos.sh.

Troubleshooting

• grub-mkrescue not found: Use grub2-mkrescue or install GRUB utilities, plus xorriso and mtools.
• QEMU not found: Install qemu-system-x86_64 (and qemu-img/qemu-utils).
• ISO creation fails: Ensure /usr/lib/grub/i386-pc/ exists on your distro or adjust the path in Meta/mounting_mockos.sh.
• LSP not seeing includes: Generate compile_commands.json with Meta/generate_compile_commands.sh and point your tools to it.

Run Tests

In the xmake are configured to run tests from LibC and LibFK on Userland to garantee max security

In new PR's on LibC/LibFK are mandatory additions of tests.

And you can compile them with:

xmake -bv Test # Build target Test

and run with:

xmake run Test # Run target Test

License

See LICENSE.