docs: rust: quick-start: add section on Linux distributions

Now that we are starting to support several Rust compiler and `bindgen`
versions, there is a good chance some Linux distributions work out of
the box.

Thus, provide some instructions on how to set the toolchain up for a
few major Linux distributions. This simplifies the setup users need to
build the kernel.

In addition, add an introduction to the document so that it is easier
to understand its structure and move the LLVM+Rust kernel.org toolchains
paragraph there (removing "depending on the Linux version"). We may want
to reorganize the document or split it in the future, but I wanted to
focus this commit on the new information added about each particular
distribution.

Finally, remove the `rustup`'s components mention in `changes.rst` since
users do not need it if they install the toolchain via the distributions
(and anyway it was too detailed for that main document).

Cc: Jan Alexander Steffens <[email protected]>
Cc: Johannes Löthberg <[email protected]>
Cc: Fabian Grünbichler <[email protected]>
Cc: Josh Stone <[email protected]>
Cc: Randy Barlow <[email protected]>
Cc: Anna (navi) Figueiredo Gomes <[email protected]>
Cc: Matoro Mahri <[email protected]>
Cc: Ryan Scheel <[email protected]>
Cc: figsoda <[email protected]>
Cc: Jörg Thalheim <[email protected]>
Cc: Theodore Ni <[email protected]>
Cc: Winter <[email protected]>
Cc: William Brown <[email protected]>
Cc: Xiaoguang Wang <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: Zixing Liu <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Tested-by: Benno Lossin <[email protected]>
Tested-by: Andreas Hindborg <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

Documentation/process/changes.rst

@@ -90,11 +90,6 @@ Rust (optional)
 
 A recent version of the Rust compiler is required.
 
-Each Rust toolchain comes with several "components", some of which are required
-(like ``rustc``) and some that are optional. The ``rust-src`` component (which
-is optional) needs to be installed to build the kernel. Other components are
-useful for developing.
-
 Please see Documentation/rust/quick-start.rst for instructions on how to
 satisfy the build requirements of Rust support. In particular, the ``Makefile``
 target ``rustavailable`` is useful to check why the Rust toolchain may not

Documentation/rust/quick-start.rst

@@ -5,24 +5,93 @@ Quick Start
 
 This document describes how to get started with kernel development in Rust.
 
+There are a few ways to install a Rust toolchain needed for kernel development.
+A simple way is to use the packages from your Linux distribution if they are
+suitable -- the first section below explains this approach. An advantage of this
+approach is that, typically, the distribution will match the LLVM used by Rust
+and Clang.
+
+Another way is using the prebuilt stable versions of LLVM+Rust provided on
+`kernel.org <https://kernel.org/pub/tools/llvm/rust/>`_. These are the same slim
+and fast LLVM toolchains from :ref:`Getting LLVM <getting_llvm>` with versions
+of Rust added to them that Rust for Linux supports. Two sets are provided: the
+"latest LLVM" and "matching LLVM" (please see the link for more information).
+
+Alternatively, the next two "Requirements" sections explain each component and
+how to install them through ``rustup``, the standalone installers from Rust
+and/or building them.
+
+The rest of the document explains other aspects on how to get started.
+
+
+Distributions
+-------------
+
+Arch Linux
+**********
+
+Arch Linux provides recent Rust releases and thus it should generally work out
+of the box, e.g.::
+
+	pacman -S rust rust-src rust-bindgen
+
+
+Debian
+******
+
+Debian Unstable (Sid), outside of the freeze period, provides recent Rust
+releases and thus it should generally work out of the box, e.g.::
+
+	apt install rustc rust-src bindgen rustfmt rust-clippy
+
+
+Fedora Linux
+************
+
+Fedora Linux provides recent Rust releases and thus it should generally work out
+of the box, e.g.::
+
+	dnf install rust rust-src bindgen-cli rustfmt clippy
+
+
+Gentoo Linux
+************
+
+Gentoo Linux (and especially the testing branch) provides recent Rust releases
+and thus it should generally work out of the box, e.g.::
+
+	USE='rust-src rustfmt clippy' emerge dev-lang/rust dev-util/bindgen
+
+``LIBCLANG_PATH`` may need to be set.
+
+
+Nix
+***
+
+Nix (unstable channel) provides recent Rust releases and thus it should
+generally work out of the box, e.g.::
+
+	{ pkgs ? import <nixpkgs> {} }:
+	pkgs.mkShell {
+	  nativeBuildInputs = with pkgs; [ rustc rust-bindgen rustfmt clippy ];
+	  RUST_LIB_SRC = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+	}
+
+
+openSUSE
+********
+
+openSUSE Slowroll and openSUSE Tumbleweed provide recent Rust releases and thus
+they should generally work out of the box, e.g.::
+
+	zypper install rust rust1.79-src rust-bindgen clang
+
 
 Requirements: Building
 ----------------------
 
 This section explains how to fetch the tools needed for building.
 
-Some of these requirements might be available from Linux distributions
-under names like ``rustc``, ``rust-src``, ``rust-bindgen``, etc. However,
-at the time of writing, they are likely not to be recent enough unless
-the distribution tracks the latest releases.
-
-Prebuilt stable versions of LLVM+Rust are provided on `kernel.org
-<https://kernel.org/pub/tools/llvm/rust/>`_. These are the same slim and fast
-LLVM toolchains from :ref:`Getting LLVM <getting_llvm>` with versions of Rust
-added to them that Rust for Linux supports, depending on the Linux version. Two
-sets are provided: the "latest LLVM" and "matching LLVM" (please see the link
-for more information).
-
 To easily check whether the requirements are met, the following target
 can be used::