Merge tag 'rust-6.11' of https://github.com/Rust-for-Linux/linux

Pull Rust updates from Miguel Ojeda: "The highlight is the establishment of a minimum version for the Rust toolchain, including 'rustc' (and bundled tools) and 'bindgen'. The initial minimum will be the pinned version we currently have, i.e. we are just widening the allowed versions. That covers three stable Rust releases: 1.78.0, 1.79.0, 1.80.0 (getting released tomorrow), plus beta, plus nightly. This should already be enough for kernel developers in distributions that provide recent Rust compiler versions routinely, such as Arch Linux, Debian Unstable (outside the freeze period), Fedora Linux, Gentoo Linux (especially the testing channel), Nix (unstable) and openSUSE Slowroll and Tumbleweed. In addition, the kernel is now being built-tested by Rust's pre-merge CI. That is, every change that is attempting to land into the Rust compiler is tested against the kernel, and it is merged only if it passes. Similarly, the bindgen tool has agreed to build the kernel in their CI too. Thus, with the pre-merge CI in place, both projects hope to avoid unintentional changes to Rust that break the kernel. This means that, in general, apart from intentional changes on their side (that we will need to workaround conditionally on our side), the upcoming Rust compiler versions should generally work. In addition, the Rust project has proposed getting the kernel into stable Rust (at least solving the main blockers) as one of its three flagship goals for 2024H2 [1]. I would like to thank Niko, Sid, Emilio et al. for their help promoting the collaboration between Rust and the kernel. Toolchain and infrastructure: - Support several Rust toolchain versions. - Support several bindgen versions. - Remove 'cargo' requirement and simplify 'rusttest', thanks to 'alloc' having been dropped last cycle. - Provide proper error reporting for the 'rust-analyzer' target. 'kernel' crate: - Add 'uaccess' module with a safe userspace pointers abstraction. - Add 'page' module with a 'struct page' abstraction. - Support more complex generics in workqueue's 'impl_has_work!' macro. 'macros' crate: - Add 'firmware' field support to the 'module!' macro. - Improve 'module!' macro documentation. Documentation: - Provide instructions on what packages should be installed to build the kernel in some popular Linux distributions. - Introduce the new kernel.org LLVM+Rust toolchains. - Explain '#[no_std]'. And a few other small bits" Link: https://rust-lang.github.io/rust-project-goals/2024h2/index.html#flagship-goals [1] * tag 'rust-6.11' of https://github.com/Rust-for-Linux/linux: (26 commits) docs: rust: quick-start: add section on Linux distributions rust: warn about `bindgen` versions 0.66.0 and 0.66.1 rust: start supporting several `bindgen` versions rust: work around `bindgen` 0.69.0 issue rust: avoid assuming a particular `bindgen` build rust: start supporting several compiler versions rust: simplify Clippy warning flags set rust: relax most deny-level lints to warnings rust: allow `dead_code` for never constructed bindings rust: init: simplify from `map_err` to `inspect_err` rust: macros: indent list item in `paste!`'s docs rust: add abstraction for `struct page` rust: uaccess: add typed accessors for userspace pointers uaccess: always export _copy_[from|to]_user with CONFIG_RUST rust: uaccess: add userspace pointers kbuild: rust-analyzer: improve comment documentation kbuild: rust-analyzer: better error handling docs: rust: no_std is used rust: alloc: add __GFP_HIGHMEM flag rust: alloc: fix typo in docs for GFP_NOWAIT ...
author: Linus Torvalds <torvalds@linux-foundation.org> 2024-07-27 13:44:54 -0700
committer: Linus Torvalds <torvalds@linux-foundation.org> 2024-07-27 13:44:54 -0700
commit: 910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef (patch)
tree: e2cc9fc3c860bfe26c7a5c2479b82594b41b87bf
parent: ff30564411ffdcee49d579cb15eb13185a36e253 (diff)
parent: b1263411112305acf2af728728591465becb45b0 (diff)
download: linux-910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef.tar.gz
linux-910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef.tar.bz2
linux-910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef.zip
25 files changed, 1058 insertions, 236 deletions
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 1497e80f030e..3fc63f27c226 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -89,14 +89,7 @@ docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`.
 Rust (optional)
 ---------------
 
-A particular version of the Rust toolchain is required. Newer versions may or
-may not work because the kernel depends on some unstable Rust features, for
-the moment.
-
-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.
+A recent version of the Rust compiler is required.
 
 Please see Documentation/rust/quick-start.rst for instructions on how to
 satisfy the build requirements of Rust support. In particular, the ``Makefile``
diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
index 4bb6ac12d482..e3f388ef4ee4 100644
--- a/Documentation/rust/general-information.rst
+++ b/Documentation/rust/general-information.rst
@@ -7,6 +7,14 @@ This document contains useful information to know when working with
 the Rust support in the kernel.
 
 
+``no_std``
+----------
+
+The Rust support in the kernel can link only `core <https://doc.rust-lang.org/core/>`_,
+but not `std <https://doc.rust-lang.org/std/>`_. Crates for use in the
+kernel must opt into this behavior using the ``#![no_std]`` attribute.
+
+
 Code documentation
 ------------------
 
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
index cc3f11e0d441..d06a36106cd4 100644
--- a/Documentation/rust/quick-start.rst
+++ b/Documentation/rust/quick-start.rst
@@ -5,17 +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.
-
 To easily check whether the requirements are met, the following target
 can be used::
 
@@ -29,16 +105,15 @@ 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::
+``--path=<build-dir>`` argument to the ``set`` sub-command) and run,
+for instance::
 
-	rustup override set $(scripts/min-tool-version.sh rustc)
+	rustup override set stable
 
-This will configure your working directory to use the correct version of
+This will configure your working directory to use the given version of
 ``rustc`` without affecting your default toolchain.
 
 Note that the override applies to the current working directory (and its
@@ -65,9 +140,9 @@ version later on requires re-adding the component.
 Otherwise, if a standalone installer is used, the Rust source tree may be
 downloaded into the toolchain's installation folder::
 
-	curl -L "https://static.rust-lang.org/dist/rust-src-$(scripts/min-tool-version.sh rustc).tar.gz" |
+	curl -L "https://static.rust-lang.org/dist/rust-src-$(rustc --version | cut -d' ' -f2).tar.gz" |
 		tar -xzf - -C "$(rustc --print sysroot)/lib" \
-		"rust-src-$(scripts/min-tool-version.sh rustc)/rust-src/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
@@ -101,26 +176,22 @@ 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 via (note that this will download and build the tool from source)::
+Install it, for instance, via (note that this will download and build the tool
+from source)::
 
-	cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen-cli
+	cargo install --locked bindgen-cli
 
-``bindgen`` needs to find a suitable ``libclang`` in order to work. If it is
-not found (or a different ``libclang`` than the one found should be used),
-the process can be tweaked using the environment variables understood by
-``clang-sys`` (the Rust bindings crate that ``bindgen`` uses to access
-``libclang``):
+``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:
 
-* ``LLVM_CONFIG_PATH`` can be pointed to an ``llvm-config`` executable.
-
-* Or ``LIBCLANG_PATH`` can be pointed to a ``libclang`` shared library
-  or to the directory containing it.
-
-* Or ``CLANG_PATH`` can be pointed to a ``clang`` executable.
-
-For details, please see ``clang-sys``'s documentation at:
+	https://github.com/KyleMayes/clang-sys#linking
 
 	https://github.com/KyleMayes/clang-sys#environment-variables
 
@@ -164,20 +235,6 @@ 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
 *******
 
diff --git a/Documentation/rust/testing.rst b/Documentation/rust/testing.rst
index acfd0c2be48d..568b71b415a4 100644
--- a/Documentation/rust/testing.rst
+++ b/Documentation/rust/testing.rst
@@ -131,9 +131,8 @@ Additionally, there are the ``#[test]`` tests. These can be run using the
 
 	make LLVM=1 rusttest
 
-This requires the kernel ``.config`` and downloads external repositories. It
-runs the ``#[test]`` tests on the host (currently) and thus is fairly limited in
-what these tests can test.
+This requires the kernel ``.config``. It runs the ``#[test]`` tests on the host
+(currently) and thus is fairly limited in what these tests can test.
 
 The Kselftests
 --------------
diff --git a/Makefile b/Makefile
index 11e74386d909..2c02dafb48ce 100644
--- a/Makefile
+++ b/Makefile
@@ -445,17 +445,17 @@ KBUILD_USERLDFLAGS := $(USERLDFLAGS)
 # host programs.
 export rust_common_flags := --edition=2021 \
 			    -Zbinary_dep_depinfo=y \
-			    -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \
-			    -Dunreachable_pub -Dnon_ascii_idents \
+			    -Dunsafe_op_in_unsafe_fn \
+			    -Dnon_ascii_idents \
+			    -Wrust_2018_idioms \
+			    -Wunreachable_pub \
 			    -Wmissing_docs \
-			    -Drustdoc::missing_crate_level_docs \
-			    -Dclippy::correctness -Dclippy::style \
-			    -Dclippy::suspicious -Dclippy::complexity \
-			    -Dclippy::perf \
-			    -Dclippy::let_unit_value -Dclippy::mut_mut \
-			    -Dclippy::needless_bitwise_bool \
-			    -Dclippy::needless_continue \
-			    -Dclippy::no_mangle_with_rust_abi \
+			    -Wrustdoc::missing_crate_level_docs \
+			    -Wclippy::all \
+			    -Wclippy::mut_mut \
+			    -Wclippy::needless_bitwise_bool \
+			    -Wclippy::needless_continue \
+			    -Wclippy::no_mangle_with_rust_abi \
 			    -Wclippy::dbg_macro
 
 KBUILD_HOSTCFLAGS   := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) \
@@ -493,7 +493,6 @@ RUSTDOC		= rustdoc
 RUSTFMT		= rustfmt
 CLIPPY_DRIVER	= clippy-driver
 BINDGEN		= bindgen
-CARGO		= cargo
 PAHOLE		= pahole
 RESOLVE_BTFIDS	= $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
 LEX		= flex
@@ -559,7 +558,7 @@ KBUILD_RUSTFLAGS := $(rust_common_flags) \
 		    -Csymbol-mangling-version=v0 \
 		    -Crelocation-model=static \
 		    -Zfunction-sections=n \
-		    -Dclippy::float_arithmetic
+		    -Wclippy::float_arithmetic
 
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
@@ -587,7 +586,7 @@ endif
 export RUSTC_BOOTSTRAP := 1
 
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC HOSTPKG_CONFIG
-export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
+export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN
 export HOSTRUSTC KBUILD_HOSTRUSTFLAGS
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
@@ -1959,9 +1958,12 @@ quiet_cmd_tags = GEN     $@
 tags TAGS cscope gtags: FORCE
 	$(call cmd,tags)
 
-# IDE support targets
+# Generate rust-project.json (a file that describes the structure of non-Cargo
+# Rust projects) for rust-analyzer (an implementation of the Language Server
+# Protocol).
 PHONY += rust-analyzer
 rust-analyzer:
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh
 	$(Q)$(MAKE) $(build)=rust $@
 
 # Script to generate missing namespace dependencies
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 3064314f4832..d8e4105a2f21 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -5,6 +5,7 @@
 #include <linux/fault-inject-usercopy.h>
 #include <linux/instrumented.h>
 #include <linux/minmax.h>
+#include <linux/nospec.h>
 #include <linux/sched.h>
 #include <linux/thread_info.h>
 
@@ -138,13 +139,26 @@ __copy_to_user(void __user *to, const void *from, unsigned long n)
 	return raw_copy_to_user(to, from, n);
 }
 
-#ifdef INLINE_COPY_FROM_USER
+/*
+ * Architectures that #define INLINE_COPY_TO_USER use this function
+ * directly in the normal copy_to/from_user(), the other ones go
+ * through an extern _copy_to/from_user(), which expands the same code
+ * here.
+ *
+ * Rust code always uses the extern definition.
+ */
 static inline __must_check unsigned long
-_copy_from_user(void *to, const void __user *from, unsigned long n)
+_inline_copy_from_user(void *to, const void __user *from, unsigned long n)
 {
 	unsigned long res = n;
 	might_fault();
 	if (!should_fail_usercopy() && likely(access_ok(from, n))) {
+		/*
+		 * Ensure that bad access_ok() speculation will not
+		 * lead to nasty side effects *after* the copy is
+		 * finished:
+		 */
+		barrier_nospec();
 		instrument_copy_from_user_before(to, from, n);
 		res = raw_copy_from_user(to, from, n);
 		instrument_copy_from_user_after(to, from, n, res);
@@ -153,14 +167,11 @@ _copy_from_user(void *to, const void __user *from, unsigned long n)
 		memset(to + (n - res), 0, res);
 	return res;
 }
-#else
 extern __must_check unsigned long
 _copy_from_user(void *, const void __user *, unsigned long);
-#endif
 
-#ifdef INLINE_COPY_TO_USER
 static inline __must_check unsigned long
-_copy_to_user(void __user *to, const void *from, unsigned long n)
+_inline_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
 	might_fault();
 	if (should_fail_usercopy())
@@ -171,25 +182,32 @@ _copy_to_user(void __user *to, const void *from, unsigned long n)
 	}
 	return n;
 }
-#else
 extern __must_check unsigned long
 _copy_to_user(void __user *, const void *, unsigned long);
-#endif
 
 static __always_inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (check_copy_size(to, n, false))
-		n = _copy_from_user(to, from, n);
-	return n;
+	if (!check_copy_size(to, n, false))
+		return n;
+#ifdef INLINE_COPY_FROM_USER
+	return _inline_copy_from_user(to, from, n);
+#else
+	return _copy_from_user(to, from, n);
+#endif
 }
 
 static __always_inline unsigned long __must_check
 copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (check_copy_size(from, n, true))
-		n = _copy_to_user(to, from, n);
-	return n;
+	if (!check_copy_size(from, n, true))
+		return n;
+
+#ifdef INLINE_COPY_TO_USER
+	return _inline_copy_to_user(to, from, n);
+#else
+	return _copy_to_user(to, from, n);
+#endif
 }
 
 #ifndef copy_mc_to_kernel
diff --git a/init/Kconfig b/init/Kconfig
index c41260ffe99a..a465ea9525bd 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1924,7 +1924,10 @@ config RUSTC_VERSION_TEXT
 config BINDGEN_VERSION_TEXT
 	string
 	depends on RUST
-	default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
+	# The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0
+	# (https://github.com/rust-lang/rust-bindgen/pull/2678). It can be removed when
+	# the minimum version is upgraded past that (0.69.1 already fixed the issue).
+	default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version workaround-for-0.69.0 || echo n)
 
 #
 # Place an empty function call at each tracepoint site. Can be
diff --git a/lib/usercopy.c b/lib/usercopy.c
index 499a7a7d54db..7b17b83c8042 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c
@@ -12,40 +12,18 @@
 
 /* out-of-line parts */
 
-#ifndef INLINE_COPY_FROM_USER
+#if !defined(INLINE_COPY_FROM_USER) || defined(CONFIG_RUST)
 unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	unsigned long res = n;
-	might_fault();
-	if (!should_fail_usercopy() && likely(access_ok(from, n))) {
-		/*
-		 * Ensure that bad access_ok() speculation will not
-		 * lead to nasty side effects *after* the copy is
-		 * finished:
-		 */
-		barrier_nospec();
-		instrument_copy_from_user_before(to, from, n);
-		res = raw_copy_from_user(to, from, n);
-		instrument_copy_from_user_after(to, from, n, res);
-	}
-	if (unlikely(res))
-		memset(to + (n - res), 0, res);
-	return res;
+	return _inline_copy_from_user(to, from, n);
 }
 EXPORT_SYMBOL(_copy_from_user);
 #endif
 
-#ifndef INLINE_COPY_TO_USER
+#if !defined(INLINE_COPY_TO_USER) || defined(CONFIG_RUST)
 unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	might_fault();
-	if (should_fail_usercopy())
-		return n;
-	if (likely(access_ok(to, n))) {
-		instrument_copy_to_user(to, from, n);
-		n = raw_copy_to_user(to, from, n);
-	}
-	return n;
+	return _inline_copy_to_user(to, from, n);
 }
 EXPORT_SYMBOL(_copy_to_user);
 #endif
diff --git a/rust/Makefile b/rust/Makefile
index 83f675adbfab..1f10f92737f2 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -44,17 +44,10 @@ rustc_sysroot := $(shell MAKEFLAGS= $(RUSTC) $(rust_flags) --print sysroot)
 rustc_host_target := $(shell $(RUSTC) --version --verbose | grep -F 'host: ' | cut -d' ' -f2)
 RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library
 
-ifeq ($(quiet),silent_)
-cargo_quiet=-q
+ifneq ($(quiet),)
 rust_test_quiet=-q
 rustdoc_test_quiet=--test-args -q
 rustdoc_test_kernel_quiet=>/dev/null
-else ifeq ($(quiet),quiet_)
-rust_test_quiet=-q
-rustdoc_test_quiet=--test-args -q
-rustdoc_test_kernel_quiet=>/dev/null
-else
-cargo_quiet=--verbose
 endif
 
 core-cfgs = \
@@ -135,22 +128,21 @@ quiet_cmd_rustc_test_library = RUSTC TL $<
 		@$(objtree)/include/generated/rustc_cfg $(rustc_target_flags) \
 		--crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \
 		--out-dir $(objtree)/$(obj)/test --cfg testlib \
-		--sysroot $(objtree)/$(obj)/test/sysroot \
 		-L$(objtree)/$(obj)/test \
 		--crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $<
 
-rusttestlib-build_error: $(src)/build_error.rs rusttest-prepare FORCE
+rusttestlib-build_error: $(src)/build_error.rs FORCE
 	+$(call if_changed,rustc_test_library)
 
 rusttestlib-macros: private rustc_target_flags = --extern proc_macro
 rusttestlib-macros: private rustc_test_library_proc = yes
-rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+rusttestlib-macros: $(src)/macros/lib.rs FORCE
 	+$(call if_changed,rustc_test_library)
 
-rusttestlib-bindings: $(src)/bindings/lib.rs rusttest-prepare FORCE
+rusttestlib-bindings: $(src)/bindings/lib.rs FORCE
 	+$(call if_changed,rustc_test_library)
 
-rusttestlib-uapi: $(src)/uapi/lib.rs rusttest-prepare FORCE
+rusttestlib-uapi: $(src)/uapi/lib.rs FORCE
 	+$(call if_changed,rustc_test_library)
 
 quiet_cmd_rustdoc_test = RUSTDOC T $<
@@ -159,7 +151,7 @@ quiet_cmd_rustdoc_test = RUSTDOC T $<
 	$(RUSTDOC) --test $(rust_common_flags) \
 		@$(objtree)/include/generated/rustc_cfg \
 		$(rustc_target_flags) $(rustdoc_test_target_flags) \
-		--sysroot $(objtree)/$(obj)/test/sysroot $(rustdoc_test_quiet) \
+		$(rustdoc_test_quiet) \
 		-L$(objtree)/$(obj)/test --output $(rustdoc_output) \
 		--crate-name $(subst rusttest-,,$@) $<
 
@@ -192,7 +184,6 @@ quiet_cmd_rustc_test = RUSTC T  $<
 	$(RUSTC) --test $(rust_common_flags) \
 		@$(objtree)/include/generated/rustc_cfg \
 		$(rustc_target_flags) --out-dir $(objtree)/$(obj)/test \
-		--sysroot $(objtree)/$(obj)/test/sysroot \
 		-L$(objtree)/$(obj)/test \
 		--crate-name $(subst rusttest-,,$@) $<; \
 	$(objtree)/$(obj)/test/$(subst rusttest-,,$@) $(rust_test_quiet) \
@@ -200,60 +191,15 @@ quiet_cmd_rustc_test = RUSTC T  $<
 
 rusttest: rusttest-macros rusttest-kernel
 
-# This prepares a custom sysroot with our custom `alloc` instead of
-# the standard one.
-#
-# This requires several hacks:
-#   - Unlike `core` and `alloc`, `std` depends on more than a dozen crates,
-#     including third-party crates that need to be downloaded, plus custom
-#     `build.rs` steps. Thus hardcoding things here is not maintainable.
-#   - `cargo` knows how to build the standard library, but it is an unstable
-#     feature so far (`-Zbuild-std`).
-#   - `cargo` only considers the use case of building the standard library
-#     to use it in a given package. Thus we need to create a dummy package
-#     and pick the generated libraries from there.
-#   - The usual ways of modifying the dependency graph in `cargo` do not seem
-#     to apply for the `-Zbuild-std` steps, thus we have to mislead it
-#     by modifying the sources in the sysroot.
-#   - To avoid messing with the user's Rust installation, we create a clone
-#     of the sysroot. However, `cargo` ignores `RUSTFLAGS` in the `-Zbuild-std`
-#     steps, thus we use a wrapper binary passed via `RUSTC` to pass the flag.
-#
-# In the future, we hope to avoid the whole ordeal by either:
-#   - Making the `test` crate not depend on `std` (either improving upstream
-#     or having our own custom crate).
-#   - Making the tests run in kernel space (requires the previous point).
-#   - Making `std` and friends be more like a "normal" crate, so that
-#     `-Zbuild-std` and related hacks are not needed.
-quiet_cmd_rustsysroot = RUSTSYSROOT
-      cmd_rustsysroot = \
-	rm -rf $(objtree)/$(obj)/test; \
-	mkdir -p $(objtree)/$(obj)/test; \
-	cp -a $(rustc_sysroot) $(objtree)/$(obj)/test/sysroot; \
-	echo '\#!/bin/sh' > $(objtree)/$(obj)/test/rustc_sysroot; \
-	echo "$(RUSTC) --sysroot=$(abspath $(objtree)/$(obj)/test/sysroot) \"\$$@\"" \
-		>> $(objtree)/$(obj)/test/rustc_sysroot; \
-	chmod u+x $(objtree)/$(obj)/test/rustc_sysroot; \
-	$(CARGO) -q new $(objtree)/$(obj)/test/dummy; \
-	RUSTC=$(objtree)/$(obj)/test/rustc_sysroot $(CARGO) $(cargo_quiet) \
-		test -Zbuild-std --target $(rustc_host_target) \
-		--manifest-path $(objtree)/$(obj)/test/dummy/Cargo.toml; \
-	rm $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib/*; \
-	cp $(objtree)/$(obj)/test/dummy/target/$(rustc_host_target)/debug/deps/* \
-		$(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib
-
-rusttest-prepare: FORCE
-	+$(call if_changed,rustsysroot)
-
 rusttest-macros: private rustc_target_flags = --extern proc_macro
 rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro
-rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+rusttest-macros: $(src)/macros/lib.rs FORCE
 	+$(call if_changed,rustc_test)
 	+$(call if_changed,rustdoc_test)
 
 rusttest-kernel: private rustc_target_flags = --extern alloc \
     --extern build_error --extern macros --extern bindings --extern uapi
-rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \
+rusttest-kernel: $(src)/kernel/lib.rs \
     rusttestlib-build_error rusttestlib-macros rusttestlib-bindings \
     rusttestlib-uapi FORCE
 	+$(call if_changed,rustc_test)
@@ -421,7 +367,7 @@ ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),)
 endif
 
 $(obj)/core.o: private skip_clippy = 1
-$(obj)/core.o: private skip_flags = -Dunreachable_pub
+$(obj)/core.o: private skip_flags = -Wunreachable_pub
 $(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym))
 $(obj)/core.o: private rustc_target_flags = $(core-cfgs)
 $(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs FORCE
@@ -435,7 +381,7 @@ $(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
 	+$(call if_changed_dep,rustc_library)
 
 $(obj)/alloc.o: private skip_clippy = 1
-$(obj)/alloc.o: private skip_flags = -Dunreachable_pub
+$(obj)/alloc.o: private skip_flags = -Wunreachable_pub
 $(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs)
 $(obj)/alloc.o: $(RUST_LIB_SRC)/alloc/src/lib.rs $(obj)/compiler_builtins.o FORCE
 	+$(call if_changed_dep,rustc_library)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 53c996e4bedf..b940a5777330 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -30,4 +30,5 @@ const gfp_t RUST_CONST_HELPER_GFP_KERNEL = GFP_KERNEL;
 const gfp_t RUST_CONST_HELPER_GFP_KERNEL_ACCOUNT = GFP_KERNEL_ACCOUNT;
 const gfp_t RUST_CONST_HELPER_GFP_NOWAIT = GFP_NOWAIT;
 const gfp_t RUST_CONST_HELPER___GFP_ZERO = __GFP_ZERO;
+const gfp_t RUST_CONST_HELPER___GFP_HIGHMEM = ___GFP_HIGHMEM;
 const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ROTATIONAL = BLK_FEAT_ROTATIONAL;
diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs
index 40ddaee50d8b..93a1a3fc97bc 100644
--- a/rust/bindings/lib.rs
+++ b/rust/bindings/lib.rs
@@ -24,6 +24,7 @@
     unsafe_op_in_unsafe_fn
 )]
 
+#[allow(dead_code)]
 mod bindings_raw {
     // Use glob import here to expose all helpers.
     // Symbols defined within the module will take precedence to the glob import.
diff --git a/rust/helpers.c b/rust/helpers.c
index 87ed0a5b6099..92d3c03ae1bd 100644
--- a/rust/helpers.c
+++ b/rust/helpers.c
@@ -26,6 +26,8 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/errname.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
 #include <linux/mutex.h>
 #include <linux/refcount.h>
 #include <linux/sched/signal.h>
@@ -40,6 +42,20 @@ __noreturn void rust_helper_BUG(void)
 }
 EXPORT_SYMBOL_GPL(rust_helper_BUG);
 
+unsigned long rust_helper_copy_from_user(void *to, const void __user *from,
+					 unsigned long n)
+{
+	return copy_from_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_user);
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from,
+				       unsigned long n)
+{
+	return copy_to_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_user);
+
 void rust_helper_mutex_lock(struct mutex *lock)
 {
 	mutex_lock(lock);
@@ -81,6 +97,24 @@ int rust_helper_signal_pending(struct task_struct *t)
 }
 EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
 
+struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+	return alloc_pages(gfp_mask, order);
+}
+EXPORT_SYMBOL_GPL(rust_helper_alloc_pages);
+
+void *rust_helper_kmap_local_page(struct page *page)
+{
+	retu
author	Linus Torvalds <torvalds@linux-foundation.org>	2024-07-27 13:44:54 -0700
committer	Linus Torvalds <torvalds@linux-foundation.org>	2024-07-27 13:44:54 -0700
commit	910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef (patch)
tree	e2cc9fc3c860bfe26c7a5c2479b82594b41b87bf
parent	ff30564411ffdcee49d579cb15eb13185a36e253 (diff)
parent	b1263411112305acf2af728728591465becb45b0 (diff)
download	linux-910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef.tar.gz linux-910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef.tar.bz2 linux-910bfc26d16d07df5a2bfcbc63f0aa9d1397e2ef.zip