A minimal x86 kernel

18 Aug 2015

This post explains how to create a minimal x86 operating system kernel. In fact, it will just boot and print OK to the screen. The following blog posts we will extend it using the Rust programming language.

Entering Long Mode

25 Aug 2015 (updated on 29 Oct 2015)

In the previous post we created a minimal multiboot kernel. It just prints OK and hangs. The goal is to extend it and call 64-bit Rust code. But the CPU is currently in protected mode and allows only 32-bit instructions and up to 4GiB memory. So we need to set up Paging and switch to the 64-bit long mode first.

Set Up Rust

02 Sep 2015

In the previous posts we created a minimal Multiboot kernel and switched to Long Mode. Now we can finally switch to Rust code. Rust is a high-level language without runtime. It allows us to not link the standard library and write bare metal code. Unfortunately the setup is not quite hassle-free yet.

Printing to Screen

23 Oct 2015

In the previous post we switched from assembly to Rust, a systems programming language that provides great safety. But so far we are using unsafe features like raw pointers whenever we want to print to screen. In this post we will create a Rust module that provides a safe and easy-to-use interface for the VGA text buffer. It will support Rust's formatting macros, too.

Memory Management

Allocating Frames

15 Nov 2015

In this post we create an allocator that provides free physical frames for a future paging module. To get the required information about available and used memory we use the Multiboot information structure. Additionally, we improve the panic handler to print the corresponding message and source line.

Page Tables

09 Dec 2015

In this post we will create a paging module, which allows us to access and modify the 4-level page table. We will explore recursive page table mapping and use some Rust features to make it safe. Finally we will create functions to translate virtual addresses and to map and unmap pages.