This Month in Rust OSDev: December 2022

content/this-month/2022-12/index.md

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+title = "This Month in Rust OSDev: December 2022"
+date = 2023-01-09
+
+[extra]
+month = "December 2022"
+editors = ["phil-opp"]
++++
+
+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.
+
+<!-- more -->
+
+This series is openly developed [on GitHub](https://github.com/rust-osdev/homepage/). 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](https://github.com/rust-osdev/homepage/issues/new) or using our <a href="#comment-form">_comment form_</a> at the bottom of this page.
+
+<!--
+    This is a draft for the upcoming "This Month in Rust OSDev (December 2022)" post.
+    Feel free to create pull requests against the `next` branch to add your
+    content here.
+    Please take a look at the past posts on https://rust-osdev.com/ to see the
+    general structure of these posts.
+-->
+
+## Infrastructure and Tooling
+
+In this section, we collect recent updates to `rustc`, `cargo`, and other tooling that are relevant to Rust OS development.
+
+<!--
+    Please use the following template:
+
+    ### Summary
+    <span class="maintainers">(Section written by [@author](https://github.com/author))</span>
+
+    <text>
+-->
+
+### [Experimental feature gate proposal `interoperable_abi`](https://github.com/rust-lang/rust/pull/105586)
+
+This Rust language proposal suggests to create a new `extern "interop"` ABI as a strict superset of the C ABI.
+The goal of this new ABI is to "define a standard way to make calls across high-level languages, passing high-level data types, without dropping to the lowest common denominator of C".
+For example, it will define a specific memory representation for strings, tuples, and common standard library types such as `Option` and `Result`.
+
+This new ABI would be very useful for operating system development because there are often multiple executables that need to communicate with each other using a stable ABI.
+For example, user-space programs communicate with the kernel using [system calls](https://en.wikipedia.org/wiki/System_call), and with each other porgrams using different forms of [inter-process communication](https://en.wikipedia.org/wiki/Inter-process_communication).
+With new `extern "interop"` ABI, these communication boundaries could use safe, higher-level types when both sides are written in Rust.
+
+### [`default_alloc_error_handler` has been stabilized](https://github.com/rust-lang/rust/pull/102318)
+
+On `no_std` targets, enabling `alloc` requires providing an OOM (out-of-memory) handler. The usual implementation of this handler just panics, but implementing the handler requires an unstable feature: [`alloc_error_handler`]. The newly-stabilized `default_alloc_error_handler` automatically provides an OOM handler that panics if no custom handler is implemented. This is an [important step towards using some targets on the stable channel][towards-stable].
+
+[`alloc_error_handler`]: https://doc.rust-lang.org/unstable-book/language-features/alloc-error-handler.html#alloc_error_handler
+[towards-stable]: https://github.com/rust-lang/rust/pull/102318#issuecomment-1331865137
+
+## Announcements, News, and Blog Posts
+
+<!--
+Here we collect news, blog posts, etc. related to OS development in Rust.
+Please follow this template:
+
+- [Title](https://example.com)
+  - (optional) Some additional context
+-->
+
+- [Linux 6.1 Released With MGLRU, Initial Rust Code](https://www.phoronix.com/news/Linux-6.1-Released)
+- [Kernel/Boot: Cope with a Relocation by a Bootloader in 32-bit x86 Assembly Code](https://phip1611.de/blog/kernel-boot-cope-with-a-relocation-by-a-bootloader-in-32-bit-x86-assembly-code/) \
+  In this blogpost, [@phip1611](https://github.com/phip1611) shows you how you can cope with a
+  relocation by a bootloader in x86 32-bit assembly code.
+- [How Does the “File Size is Smaller Than Mem Size” Optimization Work in GNU ld for the .bss Section?](https://phip1611.de/blog/how-does-the-file-size-is-smaller-than-mem-size-optimization-work-in-gnu-ld/) \
+  In this blogpost, [@phip1611](https://github.com/phip1611) explains what properties bring the GNU 
+  linker ld to save disk space, as symbols in the `.bss` section do not need to be statically 
+  allocated inside the ELF. Symbols in the `.bss` segment are expected to be initialized to all 
+  zeroes.
+- [GNU ld: Linking .bss into .data to Ensure that Mem Size Equals File Size For Each LOAD Segment (.bss in a PROGBITS Section)](https://phip1611.de/blog/linking-bss-into-data-to-ensure-the-mem-size-equals-file-size-for-each-load-segment-bss-in-a-progbits-section/) \
+  In this blogpost, [@phip1611](https://github.com/phip1611) explains what steps you have to do
+  that the GNU linker put's all symbols of the `.bss` section "as they are" into the binary
+  so that they occupy zeroed memory in the ELF. This is relevant for some very rudimentary 
+  ELF loaders that are found in some microkernels to bootstrap their initial process.
+- [The Probably Simplest x86 Driver Written in Assembly – Printing to QEMU’s debugcon-Device)](https://phip1611.de/blog/the-probably-simplest-x86-driver-written-in-assembly-printing-to-qemus-debugcon-device/) \
+  In this blogpost, [@phip1611](https://github.com/phip1611) codes with you probably the simplest
+  driver that one can write in assembly. *This blogpost is from September but wasn't mentioned here 
+  earlier.*
+
+## `rust-osdev` Projects
+
+In this section, we give an overview of notable changes to the projects hosted under the [`rust-osdev`] organization.
+
+[`rust-osdev`]: https://github.com/rust-osdev/about
+
+<!--
+    Please use the following template:
+
+    ### [`repo_name`](https://github.com/rust-osdev/repo_name)
+    <span class="maintainers">Maintained by [@maintainer_1](https://github.com/maintainer_1)</span>
+
+    The `repo_name` crate ...<<short introduction>>...
+
+    We merged the following changes this month:
+    <<changelog, either in list or text form>>
+-->
+
+### [`uefi-rs`](https://github.com/rust-osdev/uefi-rs)
+
+<span class="maintainers">Maintained by [@GabrielMajeri](https://github.com/GabrielMajeri), [@nicholasbishop](https://github.com/nicholasbishop), and [@phip1611](https://github.com/phip1611)</span>
+
+The `uefi` crate provides safe and performant wrappers for [UEFI](https://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface), the successor to the BIOS.
+
+We merged the following changes last month:
+
+#### Features
+
+- [Implement `SIMPLE_NETWORK_PROTOCOL`](https://github.com/rust-osdev/uefi-rs/pull/606)
+- [Initial support for TCG TPM protocols](https://github.com/rust-osdev/uefi-rs/pull/605)
+- [Add `unsafe_protocol` macro and drop use of the unstable `negative_impls` feature](https://github.com/rust-osdev/uefi-rs/pull/607)
+- [`UnalignedSlice`: impl `Clone` and improve `Debug`](https://github.com/rust-osdev/uefi-rs/pull/603)
+- [Implement `Error` and `Display` traits for `FromStrError`](https://github.com/rust-osdev/uefi-rs/pull/610)
+- [Simplification: No longer return "impl Iterator"](https://github.com/rust-osdev/uefi-rs/pull/619)
+- [uefi: Add `ptr_meta` dependency](https://github.com/rust-osdev/uefi-rs/pull/621)
+- [Drop unstable `maybe_uninit_slice` and `vec_into_raw_parts` features](https://github.com/rust-osdev/uefi-rs/pull/622)
+
+#### Fixes
+
+- [uefi: bug fix found by clippy](https://github.com/rust-osdev/uefi-rs/pull/620)
+
+#### Docs
+
+- [Add list of possible errors to `BootServices::open_protocol` docs](https://github.com/rust-osdev/uefi-rs/pull/600)
+- [Add list of possible errors to some `BootServices` function docs](https://github.com/rust-osdev/uefi-rs/pull/602)
+- [Add docs to `BootServices` functions describing error cases](https://github.com/rust-osdev/uefi-rs/pull/604)
+- [Shortened error documentation for all methods in `BootServices`](https://github.com/rust-osdev/uefi-rs/pull/608)
+- [Replaced UEFI chapter numbers with function identifiers in the docs](https://github.com/rust-osdev/uefi-rs/pull/611)
+- [Add some documentation for media protocols](https://github.com/rust-osdev/uefi-rs/pull/614)
+
+#### Tooling
+
+- [xtask: Update to mbrman 0.5.1](https://github.com/rust-osdev/uefi-rs/pull/601)
+- [Editorconfig: switch to max line width of 80](https://github.com/rust-osdev/uefi-rs/pull/615)
+
+
+Thanks to [@veluca93](https://github.com/veluca93), [@phip1611](https://github.com/phip1611), and [@raccog](https://github.com/raccog) for their contributions!
+
+
+### [`x86_64`](https://github.com/rust-osdev/x86_64)
+
+<span class="maintainers">Maintained by [@phil-opp](https://github.com/phil-opp), [@josephlr](https://github.com/orgs/rust-osdev/people/josephlr), [@Freax13](https://github.com/orgs/rust-osdev/people/Freax13), and [@rybot666](https://github.com/orgs/rust-osdev/people/rybot666)</span>
+
+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.
+
+We merged the following changes in December:
+
+- [Adding `next_higher_level` to `PageLevelIndex`](https://github.com/rust-osdev/x86_64/pull/400)
+- [Adding `is_empty` to `PageTable`](https://github.com/rust-osdev/x86_64/pull/399)
+- [fix `Page::from_page_table_indices`](https://github.com/rust-osdev/x86_64/pull/398) <span class="gray">(for upcoming `v0.15` release)</span>
+
+Thanks to [@TornaxO7](https://github.com/TornaxO7) for their contribution!
+
+
+## Call for Participation
+
+Want to contribute to a Rust OSDev project, but don't know where to start? Help with one of these outstanding issues!
+
+<!--
+    Please use the following template for adding items:
+    - [(`repo_name`) Issue Description](https://example.com/link-to-issue)
+-->
+
+<span class="gray">
+
+_No tasks were proposed for this section this month._
+
+</span>
+
+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](https://github.com/rust-osdev/homepage/pulls) 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](https://github.com/rust-osdev/homepage/pulls) with the updates of your OS project for the next post.
+
+### [Theseus OS](https://github.com/theseus-os/Theseus)
+
+<span class="maintainers">(Section written by [Kevin Boos](https://www.theseus-os.com/kevinaboos/) ([@kevinaboos](https://github.com/kevinaboos)))</span>
+
+Theseus is a safe-language OS written from scratch in Rust that is in the midst of a shift from academic research to usability and legacy compatibility. 
+Theseus loads and links all components at runtime, and executes everything at a single privilege level in a single address space, relying on Rust safety for isolation and correctness.
+
+As a fully open-source project, we welcome and encourage contributions from everyone!
+
+Since our [last update](https://rust-osdev.com/this-month/2022-09/index.html#theseus-os) here a few months ago, we have worked on the following things:
+* Introduced `dreadnought`, a basic async executor that brings Rust's `async`/`await` syntax to Theseus
+    * Usable by both applications and low-level kernel components
+    * Integrated the concept of wakers with Theseus's native task subsystem
+    * Currently, there is a 1-to-1 relationship between async `dreadnought` tasks and native Theseus tasks
+* Rewrote our networking interface to offer better, simpler, and cleaner abstractions
+    * It now supports the latest `smoltcp` version, `0.8`
+* Added support for booting Theseus on UEFI
+    * Previously, Theseus could boot from only multiboot2-compliant bootloaders using legacy BIOS
+    * UEFI on x86_64 now successfully boots after significant redesign of early bootstrap routines
+    * New custom `uefi_loader` tool, loosely based on the rust-osdev org's `bootloader` project
+    * Early graphical display for basic text printing is a work-in-progress
+    * UEFI is required to boot Theseus on aarch64; this is also a work-in-progress
+* Almost completed porting core subsystems to aarch64
+    * Bootstrap and logging over UART
+    * Memory management: page table modification, arch-agnostic PTE flags and basic memory types, etc
+    * Basic context switching and task bootstrap
+    * SMP multicore, plus identification of CPU cores
+    * Interrupt handling via GIC
+* Redesigned the drivers for PS/2 controller, keyboard, and mouse in an intralingual manner that fully leverages Rust's strong type system.  
+* Started implementing a brand new graphics stack and window manager, `Porthole`, from scratch
+    * Added support for x86's Page Attribute Table, which allows Theseus to control the caching properties of individual memory pages
+    * We now map graphics video memory as *write-combining* instead of cache-disabled, which significantly improves performance
+* Redesigned task management to give arbitrary tasks fewer privileges
+    * Two new types: `JoinableTaskRef` and `ExitableTaskRef`
+        * `JoinableTaskRef` is similar to `std::task::JoinHandle`, but is fully safe
+            * Ensures that a task can only be `join`ed by the "parent" task that spawned it
+            * Remove distinction between `join`ing a task and obtaining its `ExitValue`
+            * Automatically reaps "orphan" tasks that are no longer joinable
+        * `ExitableTaskRef` statically ensures that only a task itself can mark itself as exited
+            * Now, a given task can no longer invalidly mark another arbitrary task as exited
+    * Refactored scheduler and task switching to not hold any `TaskRef`s during a context switch
+        * Ensures that exited tasks are dropped and cleaned up expediently
+    * Native ELF Thread-Local Storage (TLS) variables are used to store the current task
+        * Accessing the current task is much faster, albeit slightly more complicated to initialize
+* Implemented a new shell called `hull`, plus new terminal, console, and TTY components
+    * Theseus can now run headlessly, e.g., interactively over a serial port instead of via a graphical display. 
+* Removed usage of `owning_ref`, a crate with unsoundness, in favor of our own types:
+    * `BorrowedMappedPages<T>`: a pseudo-self-referential type that allows persistent, efficient borrowing of a `MappedPages` memory region as a specific type `T`
+        * Accepts a `Mutability` type parameter for either immutable (`&T`) or mutable (`&mut T`) borrowing 
+        * Sister type `BorrowedSliceMappedPages` also supports dynamically-sized slices, i.e., `&[T]` and `&mut [T]`
+        * Much more efficient than `owning_ref` because `MappedPages` is always pinned in memory, avoiding the need for `Box` allocation
+    * `dereffer`: a new library crate that provides `DerefsTo<T>`, a generic wrapper type that allows the enclosed object `T` to be arbitrarily dereferenced to *any* inner type reachable from that object `T`
+        * Supports much more arbitrary and complex deref functions than `std::ops::Deref`
+* Canonicalized the content of Theseus's `x86_64-unknown-theseus` target spec
+    * Codegen flags are now moved into the target spec, making out-of-tree builds easier and more repeatable
+    * Target specs are now ready to be upstreamed into `rustc` as built-in targets
+* `owned_borrowed_trait`: a new library crate that abstracts over Owned values vs. Borrowed refs
+    * Uses traits and marker types instead of the existing enum-based designs (like `Cow`)
+    * Doesn't require `Clone` or care about any characteristics of the inner type `T`
+    * Allows you to use generics and associated `const`s to conditionally branch based on whether an owned value or borrowed reference was passed into a function
+    * Allows you to return a different (generic) type from a function based on whether an owned value or borrowed reference was passed in
+
+Check out the [Theseus OS blog](https://www.theseus-os.com/) for more.
+
+### [`Andy-Python-Programmer/Aero`](https://github.com/Andy-Python-Programmer/aero)
+
+<span class="maintainers">(Section written by [@Andy-Python-Programmer](https://github.com/Andy-Python-Programmer))</span>
+
+Aero is a new modern, experimental, unix-like operating system following the monolithic kernel design. Supporting modern PC features such as long mode, 5-level paging, and SMP (multicore), to name a few. 
+
+This month, Aero successfully managed to get [`mesa-demos`](https://github.com/freedesktop/mesa-demos) and [`alacritty`](https://github.com/alacritty/alacritty) running.
+
+![Aero](aero.png)
+
+In addition, `deps.sh` script was added to automate the process of installing the required dependencies on the host to build the sysroot.
+
+### [`phil-opp/blog_os`](https://github.com/phil-opp/blog_os)
+<span class="maintainers">(Section written by [@phil-opp](https://github.com/phil-opp))</span>
+
+We merged the following changes to the [_Writing an OS in Rust_](https://os.phil-opp.com/) blog in the past two months:
+
+- [[Chinese] Translate posts 5-8 and improve translation of posts 1-4](https://github.com/phil-opp/blog_os/pull/1131)
+  - Thanks to [@liuyuran](https://github.com/liuyuran) for creating this translation.
+  - Thanks to [@JiangengDong](https://github.com/JiangengDong) and [@Byacrya](https://github.com/Byacrya) for reviewing.
+- [[Translation][Korean] post-06](https://github.com/phil-opp/blog_os/pull/1175) and [[Translation][Korean] post-07](https://github.com/phil-opp/blog_os/pull/1177)
+  - Thanks to [@JOE1994](https://github.com/JOE1994) for creating these translations.
+  - Thanks to [@dalinaum](https://github.com/dalinaum) for reviewing.
+- [French translation's links fixes](https://github.com/phil-opp/blog_os/pull/1166) <span class="gray">(thanks to [@alaincao](https://github.com/alaincao))
+- [Specify latest 0.9 patch version of `bootloader`](https://github.com/phil-opp/blog_os/pull/1176) <span class="gray">(thanks to [@seewishnew](https://github.com/seewishnew))
+
+<!--
+    Please use the following template:
+
+    ### [`owner_name/repo_name`](https://github.com/rust-osdev/owner_name/repo_name)
+    <span class="maintainers">(Section written by [@your_github_name](https://github.com/your_github_name))</span>
+
+    ...<<your project updates>>...
+-->
+
+## 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 [gitter channel](https://gitter.im/rust-osdev/Lobby).