Writing an OS in Rust

Philipp Oppermann's blog

Writing an OS in Rust

This blog series creates a small operating system in the Rust programming language. Each post is a small tutorial and includes all needed code, so you can follow along if you like. The source code is also available in the corresponding Github repository.

Latest post: Async/Await

獨立的 Rust 二進制檔

建立我們自己的作業系統核心的第一步是建立一個不連結標準函式庫的 Rust 執行檔,這使得無需基礎作業系統即可在裸機上執行 Rust 程式碼。

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A Minimal Rust Kernel

In this post, we create a minimal 64-bit Rust kernel for the x86 architecture. We build upon the freestanding Rust binary from the previous post to create a bootable disk image that prints something to the screen.

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VGA Text Mode

The VGA text mode is a simple way to print text to the screen. In this post, we create an interface that makes its usage safe and simple by encapsulating all unsafety in a separate module. We also implement support for Rust’s formatting macros.

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This post explores unit and integration testing in no_std executables. We will use Rust’s support for custom test frameworks to execute test functions inside our kernel. To report the results out of QEMU, we will use different features of QEMU and the bootimage tool.

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CPU Exceptions

CPU exceptions occur in various erroneous situations, for example, when accessing an invalid memory address or when dividing by zero. To react to them, we have to set up an interrupt descriptor table that provides handler functions. At the end of this post, our kernel will be able to catch breakpoint exceptions and resume normal execution afterward.

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Double Faults

This post explores the double fault exception in detail, which occurs when the CPU fails to invoke an exception handler. By handling this exception, we avoid fatal triple faults that cause a system reset. To prevent triple faults in all cases, we also set up an Interrupt Stack Table to catch double faults on a separate kernel stack.

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Hardware Interrupts

In this post, we set up the programmable interrupt controller to correctly forward hardware interrupts to the CPU. To handle these interrupts, we add new entries to our interrupt descriptor table, just like we did for our exception handlers. We will learn how to get periodic timer interrupts and how to get input from the keyboard.

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Introduction to Paging

This post introduces paging, a very common memory management scheme that we will also use for our operating system. It explains why memory isolation is needed, how segmentation works, what virtual memory is, and how paging solves memory fragmentation issues. It also explores the layout of multilevel page tables on the x86_64 architecture.

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Paging Implementation

This post shows how to implement paging support in our kernel. It first explores different techniques to make the physical page table frames accessible to the kernel and discusses their respective advantages and drawbacks. It then implements an address translation function and a function to create a new mapping.

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Heap Allocation

This post adds support for heap allocation to our kernel. First, it gives an introduction to dynamic memory and shows how the borrow checker prevents common allocation errors. It then implements the basic allocation interface of Rust, creates a heap memory region, and sets up an allocator crate. At the end of this post, all the allocation and collection types of the built-in alloc crate will be available to our kernel.

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Allocator Designs

This post explains how to implement heap allocators from scratch. It presents and discusses different allocator designs, including bump allocation, linked list allocation, and fixed-size block allocation. For each of the three designs, we will create a basic implementation that can be used for our kernel.

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在這篇文章中,我們將探索 協作式多任務 和 Rust 的 async/await 功能。我們將詳細了解 Rust 中的 async/await 是如何工作的, 包括 Future trait 的設計、狀態機轉換和 pinning。 然後,我們通過創建一個異步鍵盤任務和一個基本的執行器,為我們的內核添加了對 async/await 的基本支持。

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Status Updates

These posts give a regular overview of the most important changes to the blog and the tools and libraries behind the scenes.

First Edition

You are currently viewing the second edition of “Writing an OS in Rust”. The first edition is very different in many aspects, for example it builds upon the GRUB bootloader instead of using the `bootloader` crate. In case you're interested in it, it is still available. Note that the first edition is no longer updated and might contain outdated information. read the first edition »

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