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
  ...

1 files changed, 10 insertions, 64 deletions

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)