Writing an OS in Rust (First Edition)
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: Double Faults
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.
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.read more »
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.read more »
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.
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.read more »
In this post we will create a new page table to map the kernel sections correctly. Therefore we will extend the paging module to support modifications of inactive page tables as well. Then we will switch to the new table and secure our kernel stack by creating a guard page.read more »
In this post, we start exploring CPU exceptions. Exceptions occur in various erroneous situations, for example when accessing an invalid memory address or when dividing by zero. To catch 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 to resume normal execution afterwards.read more »