lanru / os_kernel_lab

OS kernel labs based on Rust/C Lang & RISC-V 64/X86-32

rCore-Tutorial-v3

rCore-Tutorial version 3.5. See the Documentation in Chinese.

news

• 2021.11.20: Now we are updating our labs. Please checkout chX-dev Branches for our current new labs. (Notice: please see the [Dependency] section in the end of this doc)

Overview

This project aims to show how to write an Unix-like OS running on RISC-V platforms from scratch in Rust for beginners without any background knowledge about computer architectures, assembly languages or operating systems.

Features

• Platform supported: qemu-system-riscv64 simulator or dev boards based on Kendryte K210 SoC such as Maix Dock
• OS
  • concurrency of multiple processes
  • preemptive scheduling(Round-Robin algorithm)
  • dynamic memory management in kernel
  • virtual memory
  • a simple file system with a block cache
  • an interactive shell in the userspace
• only 4K+ LoC
• A detailed documentation in Chinese in spite of the lack of comments in the code(English version is not available at present)

Run our project

TODO:

Working in progress

Now we are still updating our project, you can find latest changes on branches chX-dev such as ch1-dev. We are intended to publish first release 3.5.0 after completing most of the tasks mentioned below.

Overall progress: ch7

Completed

• automatically clean up and rebuild before running our project on a different platform
• fix power series application in early chapters, now you can find modulus in the output
• use UPSafeCell instead of RefCell or spin::Mutex in order to access static data structures and adjust its API so that it cannot be borrowed twice at a time(mention & .exclusive_access().task[0] in run_first_task)
• move TaskContext into TaskControlBlock instead of restoring it in place on kernel stack(since ch3), eliminating annoying task_cx_ptr2
• replace llvm_asm! with asm!
• expand the fs image size generated by rcore-fs-fuse to 128MiB
• add a new test named huge_write which evaluates the fs performance(qemu~500KiB/s k210~50KiB/s)
• flush all block cache to disk after a fs transaction which involves write operation
• replace spin::Mutex with UPSafeCell before SMP chapter
• add codes for a new chapter about synchronization & mutual exclusion(uniprocessor only)

Todo(High priority)

• support Allwinner's RISC-V D1 chip
• bug fix: we should call find_pte rather than find_pte_create in PageTable::unmap
• bug fix: check validity of level-3 pte in find_pte instead of checking it outside this function
• use old fs image optionally, do not always rebuild the image
• add new system calls: getdents64/fstat
• shell functionality improvement(to be continued...)
• give every non-zero process exit code an unique and clear error type
• effective error handling of mm module

Todo(Low priority)

• rewrite practice doc and remove some inproper questions
• provide smooth debug experience at a Rust source code level
• format the code using official tools

Crates

We will add them later.