rCore-Tutorial-v3/README.md

rCore-Tutorial-v3

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

Official QQ group number: 735045051

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 each of which contains mutiple native threads
  • 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

Our first release 3.5.0 (chapter 1-7) has been published.

There will be 9 chapters in our next release 3.6.0, where 2 new chapters will be added:

• chapter 8: synchronization on a uniprocessor
• chapter 9: I/O devices

Current version is 3.6.0-alpha.1 and we are still working on it.

Here are the updates since 3.5.0:

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)
• bug fix: we should call find_pte rather than find_pte_create in PageTable::unmap
• clarify: "check validity of level-3 pte in find_pte instead of checking it outside this function" should not be a bug
• code of chapter 8: synchronization on a uniprocessor
• switch the code of chapter 6 and chapter 7

Todo(High priority)

• review documentation, current progress: 5/9
• support signal mechanism in chapter 7
• code of chapter 9: device drivers based on interrupts, including UART and block devices
• 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
• support other platforms

Crates

We will add them later.