This Month in Rust OSDev: February 2022

Welcome to a new issue of "This Month in Rust OSDev". In these posts, we give a regular overview of notable changes in the Rust operating system development ecosystem.

This series is openly developed on GitHub. Feel free to open pull requests there with content you would like to see in the next issue. If you find some issues on this page, please report them by creating an issue or using our comment form at the bottom of this page.

Project Updates

In this section, we give an overview of notable changes to the projects hosted under the rust-osdev organization.

uefi-rs

Maintained by @GabrielMajeri and @nicholasbishop

The uefi crate provides safe and performant wrappers for UEFI, the successor to the BIOS.

One of the pain points of developers building software using uefi-rs has been the Completion type, which is like an expanded Result type which also handles warnings (besides successes and errors). There's an open proposal to drop this type and revert to using more standard Results everywhere, by treating all warnings as errors. Initial feedback suggests that such a change would be beneficial to the project, but comments and suggestions are welcome on the linked issue.

We merged the following changes in February:

• Run tests on AArch64 VM in CI
• Add IA32 target to xtask and test it in CI
• Fix links in project template README file
• Remove CStr16::as_string
• Fix status code check at end of VM test
• Automatically test latest crate release on latest nightly in CI
• Fix various phrasing inconsistencies and spelling errors in protocol docs
• Remove implicit string conversion from File::open
• Expand Align trait docstring
• Add string equality operator impls
• Fix file info structures' sizes and add tests
• Implicitly run tests with +nightly
• Remove more implicit string conversions
• Add a CHANGELOG.md
• Add minimal test for LoadedImage protocol
• Fix ProtocolsPerHandle internal slice property
• Update changelog for file info changes
• Make the load options API on LoadedImage protocol safer
• Switch all packages to the 2021 edition

Thanks to @nicholasbishop, @Stzx, @avirule and @AtsukiTak for their contributions!

x86_64

Maintained by @phil-opp, @josephlr, @Freax13, and @rybot666

The x86_64 crate provides various abstractions for x86_64 systems, including wrappers for CPU instructions, access to processor-specific registers, and abstraction types for architecture-specific structures such as page tables and descriptor tables.

In February, we merged the following pull requests:

• Remove external assembly
• Implement core::iter::Step for VirtAddr and Page
• Make fields of VirtAddrNotValid and PhysAddrNotValid public
• Fix: VirtAddrNotValid and PhysAddrNotValid should contain the whole address

We also merged a few breaking changes, which will be part of the upcoming v0.15 release:

• Merge latest changes from master into next and migrate code
• Make Cr2::read return a result
• Remove external_asm and inline_asm features

bootloader

Maintained by @phil-opp, @rybot666, and @64

The bootloader crate implements a custom Rust-based bootloader for easy loading of 64-bit ELF executables.

We merged the following changes this month:

• Add ASLR
• maybe_uninit_extra is no longer feature-gated (published as v0.10.12)
• [v0.9] Remove the asm and global_asm features, which are now stable (published as v0.9.22)

Thanks to @Freax13 and @kennystrawnmusic for their contributions!

We also pushed a big restructuring to the next branch, which will become the v0.11 version eventually. The branch is still in an experimental state and not documented yet, so it's probably a bit early to try it out. But we are making good progress!

vga

Maintained by @RKennedy9064

The work-in-progress vga crate allows the configuration of the VGA hardware, e.g. switching from text-based mode to a pixel-based graphics mode. This month, we merged the following pull request:

• Set color palette to standard 256 VGA palette

Thanks to @clavierpaul for this contribution!

Call for Participation

Want to contribute to a Rust OSDev project, but don't know where to start? Pick up one of these outstanding issues in one of our projects and get started!

• (rust-osdev/uefi) Feedback requested: Treat UEFI warnings as errors
• (phil-opp/blog_os) Looking for a reviewer for a new Korean translation

If you maintain a Rust project related to operating system development and are looking for contributors, especially for tasks suited to people getting started in this space, please create a PR against the next branch with the tasks you want to include in the next issue.

Other Projects

In this section, we describe updates to Rust OS projects that are not directly related to the rust-osdev organization. Feel free to create a pull request with the updates of your OS project for the next post.

phil-opp/blog_os

(Section written by @phil-opp)

We merged two fixes for the Writing an OS in Rust blog this month:

• Fix link to MS Docs
• Fix typo in 02-minimal-rust-kernel

Thanks to @kITerE and @MaxDesiatov for these contributions!

I'm also still working on the third edition of the blog. The current state is the following:

• This month, cargo finally gained support for artifact dependencies, which is a feature that I plan to use for the edition. There are still a few issues with it, for example a panic in combination with -Zbuild-std and that there is currently no way to enable -Zbuild-std=core for an artifact dependency without enabling it globally.
• The upcoming v0.11 version of the bootloader crate is already finished for the UEFI part. I'm still working on the BIOS implementation, which is more difficult unfortunately.

Join Us?

Are you interested in Rust-based operating system development? Our rust-osdev organization is always open to new members and new projects. Just let us know if you want to join! A good way for getting in touch is our Zulip chat.

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