Qwinci / crescent

A custom OS distribution

Crescent

A custom OS distribution

Crescent is a custom operating system distribution, that is going to come with its own set of userspace applications and a desktop environment.

This repository hosts the Crescent kernel and apps.

Features

• Multithreaded pre-emptive custom kernel
• A set of custom userspace applications including a terminal, file manager, desktop environment, browser, media player and some games. (TODO, currently the only userspace application is a dummy echo "terminal")
• Works on real hardware and supports different kinds of devices
• Architectures supported: X86-64 (AArch64 support is planned)

Building the full distribution

Building the whole distribution is best done using xbstrap, the required tools for that are:

• C/C++ compiler
• xbstrap
• CMake/Meson/Ninja/Make depending on which packages are built

Steps

Downloads the prerequisites once by running:

xbstrap prereqs xbps

Clone the crescent bootstrap repository, and proceed with the instructions below in that directory.

Initialize the build directory:

mkdir build
cd build
xbstrap init ..

Installing packages is done using xbstrap install:

# install optinally accepts --rebuild argument for rebuilding the package
xbstrap install <name>

There is a set of meta-packages which you can use to build preselected sets of packages:

• base: includes the kernel and custom apps

Creating a bios/EFI bootable image:

# Create an empty image (usually only needed on a clean build)
xbstrap run create-image
# Sync the sysroot to the image
xbstrap run update-image

Booting the image in Qemu:

# Commands can be chained, for an example you can run
# `xbstrap run update-image qemu`
# to both update the image and launch qemu
xbstrap run qemu

Building the plain kernel

It is also possible build the plain Crescent kernel, for that you need following tools:

• C compiler
• CMake
• Ninja (not strictly needed, but the build commands assume Ninja is used)

Steps

Note: If you want to cross-compile to a different architecture, then refer to CMake documentation on toolchain files and add the appropriate flags to below commands.

• mkdir build
• cd build
• cmake -G Ninja ../kernel
• ninja

Todo

• Basic logging
• Memory
  • Page frame allocator
  • Page table manager
  • General purpose memory allocator
• Interrupt handling
  • APIC
  • Exceptions
  • IO-APIC
• Kernel module loading
• Per-cpu multilevel feedback queue scheduler
• ACPI
  • FADT
  • MADT
  • MCFG
  • Power management
• Filesystems
  • FAT32
  • Ext4 read
  • Ext4 write
• Drivers
  • SMP
  • AHCI SATA
  • NVMe
  • PS2
    • Keyboard
    • Mouse
  • Generic PCI device interface
  • Ethernet
    • Realtek RTL8169
  • USB
    • Generic HCI interface abstraction
    • HCI
      • UHCI
      • OHCI
      • EHCI
      • XHCI
    • Keyboard
    • Mouse
    • Mass storage