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diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst index 13b7744b1e27..152289f0bed2 100644 --- a/Documentation/rust/quick-start.rst +++ b/Documentation/rust/quick-start.rst @@ -5,17 +5,148 @@ 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 13 (Trixie), as well as Testing and Debian Unstable (Sid) provide recent +Rust releases and thus they 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 = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}"; + } + + +openSUSE +******** + +openSUSE Slowroll and openSUSE Tumbleweed provide recent Rust releases and thus +they should generally work out of the box, e.g.:: + + zypper install rust rust1.79-src rust-bindgen clang + + +Ubuntu +****** + +25.04 +~~~~~ + +The latest Ubuntu releases provide recent Rust releases and thus they should +generally work out of the box, e.g.:: + + apt install rustc rust-src bindgen rustfmt rust-clippy + +In addition, ``RUST_LIB_SRC`` needs to be set, e.g.:: + + RUST_LIB_SRC=/usr/src/rustc-$(rustc --version | cut -d' ' -f2)/library + +For convenience, ``RUST_LIB_SRC`` can be exported to the global environment. + + +24.04 LTS and older +~~~~~~~~~~~~~~~~~~~ + +Though Ubuntu 24.04 LTS and older versions still provide recent Rust +releases, they require some additional configuration to be set, using +the versioned packages, e.g.:: + + apt install rustc-1.80 rust-1.80-src bindgen-0.65 rustfmt-1.80 \ + rust-1.80-clippy + ln -s /usr/lib/rust-1.80/bin/rustfmt /usr/bin/rustfmt-1.80 + ln -s /usr/lib/rust-1.80/bin/clippy-driver /usr/bin/clippy-driver-1.80 + +None of these packages set their tools as defaults; therefore they should be +specified explicitly, e.g.:: + + make LLVM=1 RUSTC=rustc-1.80 RUSTDOC=rustdoc-1.80 RUSTFMT=rustfmt-1.80 \ + CLIPPY_DRIVER=clippy-driver-1.80 BINDGEN=bindgen-0.65 + +Alternatively, modify the ``PATH`` variable to place the Rust 1.80 binaries +first and set ``bindgen`` as the default, e.g.:: + + PATH=/usr/lib/rust-1.80/bin:$PATH + update-alternatives --install /usr/bin/bindgen bindgen \ + /usr/bin/bindgen-0.65 100 + update-alternatives --set bindgen /usr/bin/bindgen-0.65 + +``RUST_LIB_SRC`` needs to be set when using the versioned packages, e.g.:: + + RUST_LIB_SRC=/usr/src/rustc-$(rustc-1.80 --version | cut -d' ' -f2)/library + +For convenience, ``RUST_LIB_SRC`` can be exported to the global environment. + +In addition, ``bindgen-0.65`` is available in newer releases (24.04 LTS and +24.10), but it may not be available in older ones (20.04 LTS and 22.04 LTS), +thus ``bindgen`` may need to be built manually (please see below). + 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. - To easily check whether the requirements are met, the following target can be used:: @@ -29,25 +160,30 @@ if that is the case. rustc ***** -A particular version of the Rust compiler is required. Newer versions may or -may not work because, for the moment, the kernel depends on some unstable -Rust features. +A recent version of the Rust compiler is required. + +If ``rustup`` is being used, enter the kernel build directory (or use +``--path=<build-dir>`` argument to the ``set`` sub-command) and run, +for instance:: + + rustup override set stable -If ``rustup`` is being used, enter the checked out source code directory -and run:: +This will configure your working directory to use the given version of +``rustc`` without affecting your default toolchain. - rustup override set $(scripts/min-tool-version.sh rustc) +Note that the override applies to the current working directory (and its +sub-directories). -Otherwise, fetch a standalone installer or install ``rustup`` from: +If you are not using ``rustup``, fetch a standalone installer from: - https://www.rust-lang.org + https://forge.rust-lang.org/infra/other-installation-methods.html#standalone Rust standard library source **************************** The Rust standard library source is required because the build system will -cross-compile ``core`` and ``alloc``. +cross-compile ``core``. If ``rustup`` is being used, run:: @@ -56,16 +192,17 @@ If ``rustup`` is being used, run:: The components are installed per toolchain, thus upgrading the Rust compiler version later on requires re-adding the component. -Otherwise, if a standalone installer is used, the Rust repository may be cloned -into the installation folder of the toolchain:: +Otherwise, if a standalone installer is used, the Rust source tree may be +downloaded into the toolchain's installation folder:: - git clone --recurse-submodules \ - --branch $(scripts/min-tool-version.sh rustc) \ - https://github.com/rust-lang/rust \ - $(rustc --print sysroot)/lib/rustlib/src/rust + curl -L "https://static.rust-lang.org/dist/rust-src-$(rustc --version | cut -d' ' -f2).tar.gz" | + tar -xzf - -C "$(rustc --print sysroot)/lib" \ + "rust-src-$(rustc --version | cut -d' ' -f2)/rust-src/lib/" \ + --strip-components=3 In this case, upgrading the Rust compiler version later on requires manually -updating this clone. +updating the source tree (this can be done by removing ``$(rustc --print +sysroot)/lib/rustlib/src/rust`` then rerunning the above command). libclang @@ -73,7 +210,7 @@ libclang ``libclang`` (part of LLVM) is used by ``bindgen`` to understand the C code in the kernel, which means LLVM needs to be installed; like when the kernel -is compiled with ``CC=clang`` or ``LLVM=1``. +is compiled with ``LLVM=1``. Linux distributions are likely to have a suitable one available, so it is best to check that first. @@ -94,11 +231,24 @@ bindgen ******* The bindings to the C side of the kernel are generated at build time using -the ``bindgen`` tool. A particular version is required. +the ``bindgen`` tool. + +Install it, for instance, via (note that this will download and build the tool +from source):: + + cargo install --locked bindgen-cli -Install it via (note that this will download and build the tool from source):: +``bindgen`` uses the ``clang-sys`` crate to find a suitable ``libclang`` (which +may be linked statically, dynamically or loaded at runtime). By default, the +``cargo`` command above will produce a ``bindgen`` binary that will load +``libclang`` at runtime. If it is not found (or a different ``libclang`` than +the one found should be used), the process can be tweaked, e.g. by using the +``LIBCLANG_PATH`` environment variable. For details, please see ``clang-sys``'s +documentation at: - cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen + https://github.com/KyleMayes/clang-sys#linking + + https://github.com/KyleMayes/clang-sys#environment-variables Requirements: Developing @@ -140,20 +290,6 @@ can be installed manually:: The standalone installers also come with ``clippy``. -cargo -***** - -``cargo`` is the Rust native build system. It is currently required to run -the tests since it is used to build a custom standard library that contains -the facilities provided by the custom ``alloc`` in the kernel. The tests can -be run using the ``rusttest`` Make target. - -If ``rustup`` is being used, all the profiles already install the tool, -thus nothing needs to be done. - -The standalone installers also come with ``cargo``. - - rustdoc ******* @@ -179,7 +315,9 @@ be used with many editors to enable syntax highlighting, completion, go to definition, and other features. ``rust-analyzer`` needs a configuration file, ``rust-project.json``, which -can be generated by the ``rust-analyzer`` Make target. +can be generated by the ``rust-analyzer`` Make target:: + + make LLVM=1 rust-analyzer Configuration @@ -207,10 +345,6 @@ at the moment. That is:: make LLVM=1 -For architectures that do not support a full LLVM toolchain, use:: - - make CC=clang - Using GCC also works for some configurations, but it is very experimental at the moment. @@ -226,7 +360,7 @@ If GDB/Binutils is used and Rust symbols are not getting demangled, the reason is the toolchain does not support Rust's new v0 mangling scheme yet. There are a few ways out: - - Install a newer release (GDB >= 10.2, Binutils >= 2.36). +- Install a newer release (GDB >= 10.2, Binutils >= 2.36). - - Some versions of GDB (e.g. vanilla GDB 10.1) are able to use - the pre-demangled names embedded in the debug info (``CONFIG_DEBUG_INFO``). +- Some versions of GDB (e.g. vanilla GDB 10.1) are able to use + the pre-demangled names embedded in the debug info (``CONFIG_DEBUG_INFO``). |