litchi-rs

An x86-64 kernel with ~100% Rust (originally) in a week. The continuation of Litchi.

Try it

Make sure the Rust toolchains and qemu-system-x86_64 are installed, then simply execute...

make qemu PROFILE=release

Roadmap

Booting

• Bare-metal UEFI application.
• In-memory ELF program loader.
• Locate kernel executable with UEFI's simple file system.
• Jump into the kernel.
• Prepare BootInfo and pass to the kernel.
• ...

Kernel Initializations

• Serial logger.
• Global Descriptor Table & Task State Segment.
• Physical frame allocator, based on the boot info.
• Kernel page table.
• Kernel heap allocation & extern crate alloc.
• Resolve ACPI table for interrupts & multiprocessors.
• Trap handlers for critical faults.
• Local APIC for the timer interrupt.
• IO APIC for the UART serial.
• Bootstrap application processors.
• ...

User Tasks

• Load embedded ELF user programs.
• RAII-style user memory allocator and mapper.
• User library to provide init code.
• Switch to user mode.
• Frame-preserving timer interrupt handler for preemption.
• Round-robin task scheduler.
• System calls with shared memory.
• User heap allocator.
• Task recycling.
• Idle task with kernel privilege.
• Basic priority-based scheduler.
• File or device resource management.
• Blocking system calls.
• A basic userspace shell.
• Task spawning and forking.
• Synchronization primitives.
• Asynchronous IO.
• ...

Other Kernel Functionalities

• Event-driven UART serial input handler.
• Kernel task with async Rust!
• Multiprocessors.
• Simple file systems.
• IPC mechanisms.
• ...

References

• https://os.phil-opp.com
• https://github.com/BugenZhao/Litchi
• https://github.com/alesharik/distros
• https://github.com/rcore-os/rboot
• https://github.com/rcore-os/trapframe-rs
• https://osdev.org
• https://pdos.csail.mit.edu/6.828/2018/schedule.html
• ...