Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux

Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up
     objtool warnings), teach objtool about 'noreturn' Rust symbols and
     mimic '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we
     should be objtool-warning-free, so enable it to run for all Rust
     object files.

   - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support.

   - Support 'RUSTC_VERSION', including re-config and re-build on
     change.

   - Split helpers file into several files in a folder, to avoid
     conflicts in it. Eventually those files will be moved to the right
     places with the new build system. In addition, remove the need to
     manually export the symbols defined there, reusing existing
     machinery for that.

   - Relax restriction on configurations with Rust + GCC plugins to just
     the RANDSTRUCT plugin.

  'kernel' crate:

   - New 'list' module: doubly-linked linked list for use with reference
     counted values, which is heavily used by the upcoming Rust Binder.

     This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed
     unique for the given ID), 'AtomicTracker' (tracks whether a
     'ListArc' exists using an atomic), 'ListLinks' (the prev/next
     pointers for an item in a linked list), 'List' (the linked list
     itself), 'Iter' (an iterator over a 'List'), 'Cursor' (a cursor
     into a 'List' that allows to remove elements), 'ListArcField' (a
     field exclusively owned by a 'ListArc'), as well as support for
     heterogeneous lists.

   - New 'rbtree' module: red-black tree abstractions used by the
     upcoming Rust Binder.

     This includes 'RBTree' (the red-black tree itself), 'RBTreeNode' (a
     node), 'RBTreeNodeReservation' (a memory reservation for a node),
     'Iter' and 'IterMut' (immutable and mutable iterators), 'Cursor'
     (bidirectional cursor that allows to remove elements), as well as
     an entry API similar to the Rust standard library one.

   - 'init' module: add 'write_[pin_]init' methods and the
     'InPlaceWrite' trait. Add the 'assert_pinned!' macro.

   - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by
     introducing an associated type in the trait.

   - 'alloc' module: add 'drop_contents' method to 'BoxExt'.

   - 'types' module: implement the 'ForeignOwnable' trait for
     'Pin<Box<T>>' and improve the trait's documentation. In addition,
     add the 'into_raw' method to the 'ARef' type.

   - 'error' module: in preparation for the upcoming Rust support for
     32-bit architectures, like arm, locally allow Clippy lint for
     those.

  Documentation:

   - https://rust.docs.kernel.org has been announced, so link to it.

   - Enable rustdoc's "jump to definition" feature, making its output a
     bit closer to the experience in a cross-referencer.

   - Debian Testing now also provides recent Rust releases (outside of
     the freeze period), so add it to the list.

  MAINTAINERS:

   - Trevor is joining as reviewer of the "RUST" entry.

  And a few other small bits"

* tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux: (54 commits)
  kasan: rust: Add KASAN smoke test via UAF
  kbuild: rust: Enable KASAN support
  rust: kasan: Rust does not support KHWASAN
  kbuild: rust: Define probing macros for rustc
  kasan: simplify and clarify Makefile
  rust: cfi: add support for CFI_CLANG with Rust
  cfi: add CONFIG_CFI_ICALL_NORMALIZE_INTEGERS
  rust: support for shadow call stack sanitizer
  docs: rust: include other expressions in conditional compilation section
  kbuild: rust: replace proc macros dependency on `core.o` with the version text
  kbuild: rust: rebuild if the version text changes
  kbuild: rust: re-run Kconfig if the version text changes
  kbuild: rust: add `CONFIG_RUSTC_VERSION`
  rust: avoid `box_uninit_write` feature
  MAINTAINERS: add Trevor Gross as Rust reviewer
  rust: rbtree: add `RBTree::entry`
  rust: rbtree: add cursor
  rust: rbtree: add mutable iterator
  rust: rbtree: add iterator
  rust: rbtree: add red-black tree implementation backed by the C version
  ...

Documentation/rust/general-information.rst

@@ -15,6 +15,8 @@ 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.
 
 
+.. _rust_code_documentation:
+
 Code documentation
 ------------------
 
@@ -22,10 +24,17 @@ Rust kernel code is documented using ``rustdoc``, its built-in documentation
 generator.
 
 The generated HTML docs include integrated search, linked items (e.g. types,
-functions, constants), source code, etc. They may be read at (TODO: link when
-in mainline and generated alongside the rest of the documentation):
+functions, constants), source code, etc. They may be read at:
+
+	https://rust.docs.kernel.org
+
+For linux-next, please see:
+
+	https://rust.docs.kernel.org/next/
 
-	http://kernel.org/
+There are also tags for each main release, e.g.:
+
+	https://rust.docs.kernel.org/6.10/
 
 The docs can also be easily generated and read locally. This is quite fast
 (same order as compiling the code itself) and no special tools or environment
@@ -75,7 +84,7 @@ should provide as-safe-as-possible abstractions as needed.
 .. code-block::
 
 	                                                rust/bindings/
-	                                               (rust/helpers.c)
+	                                               (rust/helpers/)
 
 	                                                   include/ -----+ <-+
 	                                                                 |   |
@@ -112,7 +121,7 @@ output files in the ``rust/bindings/`` directory.
 
 For parts of the C header that ``bindgen`` does not auto generate, e.g. C
 ``inline`` functions or non-trivial macros, it is acceptable to add a small
-wrapper function to ``rust/helpers.c`` to make it available for the Rust side as
+wrapper function to ``rust/helpers/`` to make it available for the Rust side as
 well.
 
 Abstractions
@@ -142,3 +151,11 @@ configuration:
 	#[cfg(CONFIG_X="y")]   // Enabled as a built-in (`y`)
 	#[cfg(CONFIG_X="m")]   // Enabled as a module   (`m`)
 	#[cfg(not(CONFIG_X))]  // Disabled
+
+For other predicates that Rust's ``cfg`` does not support, e.g. expressions with
+numerical comparisons, one may define a new Kconfig symbol:
+
+.. code-block:: kconfig
+
+	config RUSTC_VERSION_MIN_107900
+		def_bool y if RUSTC_VERSION >= 107900

Documentation/rust/index.rst

@@ -25,13 +25,27 @@ support is still in development/experimental, especially for certain kernel
 configurations.
 
 
+Code documentation
+------------------
+
+Given a kernel configuration, the kernel may generate Rust code documentation,
+i.e. HTML rendered by the ``rustdoc`` tool.
+
 .. only:: rustdoc and html
 
-	You can also browse `rustdoc documentation <rustdoc/kernel/index.html>`_.
+	This kernel documentation was built with `Rust code documentation
+	<rustdoc/kernel/index.html>`_.
 
 .. only:: not rustdoc and html
 
-	This documentation does not include rustdoc generated information.
+	This kernel documentation was not built with Rust code documentation.
+
+A pregenerated version is provided at:
+
+	https://rust.docs.kernel.org
+
+Please see the :ref:`Code documentation <rust_code_documentation>` section for
+more details.
 
 .. toctree::
     :maxdepth: 1

Documentation/rust/quick-start.rst

@@ -39,8 +39,8 @@ of the box, e.g.::
 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.::
+Debian Testing and Debian Unstable (Sid), outside of the freeze period, 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
 

MAINTAINERS

@@ -20144,6 +20144,7 @@ R:	Björn Roy Baron <bjorn3_gh@protonmail.com>
 R:	Benno Lossin <benno.lossin@proton.me>
 R:	Andreas Hindborg <a.hindborg@kernel.org>
 R:	Alice Ryhl <aliceryhl@google.com>
+R:	Trevor Gross <tmgross@umich.edu>
 L:	rust-for-linux@vger.kernel.org
 S:	Supported
 W:	https://rust-for-linux.com

Makefile

@@ -645,9 +645,11 @@ endif
 
 # The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
 # Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
-# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
-# and from include/config/auto.conf.cmd to detect the compiler upgrade.
+# CC_VERSION_TEXT and RUSTC_VERSION_TEXT are referenced from Kconfig (so they
+# need export), and from include/config/auto.conf.cmd to detect the compiler
+# upgrade.
 CC_VERSION_TEXT = $(subst $(pound),,$(shell LC_ALL=C $(CC) --version 2>/dev/null | head -n 1))
+RUSTC_VERSION_TEXT = $(subst $(pound),,$(shell $(RUSTC) --version 2>/dev/null))
 
 ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
 include $(srctree)/scripts/Makefile.clang
@@ -668,7 +670,7 @@ ifdef config-build
 # KBUILD_DEFCONFIG may point out an alternative default configuration
 # used for 'make defconfig'
 include $(srctree)/arch/$(SRCARCH)/Makefile
-export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT
+export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT RUSTC_VERSION_TEXT
 
 config: outputmakefile scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@
@@ -924,6 +926,7 @@ ifdef CONFIG_SHADOW_CALL_STACK
 ifndef CONFIG_DYNAMIC_SCS
 CC_FLAGS_SCS	:= -fsanitize=shadow-call-stack
 KBUILD_CFLAGS	+= $(CC_FLAGS_SCS)
+KBUILD_RUSTFLAGS += -Zsanitizer=shadow-call-stack
 endif
 export CC_FLAGS_SCS
 endif
@@ -948,6 +951,16 @@ endif
 
 ifdef CONFIG_CFI_CLANG
 CC_FLAGS_CFI	:= -fsanitize=kcfi
+ifdef CONFIG_CFI_ICALL_NORMALIZE_INTEGERS
+	CC_FLAGS_CFI	+= -fsanitize-cfi-icall-experimental-normalize-integers
+endif
+ifdef CONFIG_RUST
+	# Always pass -Zsanitizer-cfi-normalize-integers as CONFIG_RUST selects
+	# CONFIG_CFI_ICALL_NORMALIZE_INTEGERS.
+	RUSTC_FLAGS_CFI   := -Zsanitizer=kcfi -Zsanitizer-cfi-normalize-integers
+	KBUILD_RUSTFLAGS += $(RUSTC_FLAGS_CFI)
+	export RUSTC_FLAGS_CFI
+endif
 KBUILD_CFLAGS	+= $(CC_FLAGS_CFI)
 export CC_FLAGS_CFI
 endif

arch/Kconfig

@@ -835,6 +835,22 @@ config CFI_CLANG
 
 	    https://clang.llvm.org/docs/ControlFlowIntegrity.html
 
+config CFI_ICALL_NORMALIZE_INTEGERS
+	bool "Normalize CFI tags for integers"
+	depends on CFI_CLANG
+	depends on $(cc-option,-fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers)
+	help
+	  This option normalizes the CFI tags for integer types so that all
+	  integer types of the same size and signedness receive the same CFI
+	  tag.
+
+	  The option is separate from CONFIG_RUST because it affects the ABI.
+	  When working with build systems that care about the ABI, it is
+	  convenient to be able to turn on this flag first, before Rust is
+	  turned on.
+
+	  This option is necessary for using CFI with Rust. If unsure, say N.
+
 config CFI_PERMISSIVE
 	bool "Use CFI in permissive mode"
 	depends on CFI_CLANG

arch/arm64/Kconfig

@@ -235,7 +235,7 @@ config ARM64
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select MMU_GATHER_RCU_TABLE_FREE
 	select HAVE_RSEQ
-	select HAVE_RUST if CPU_LITTLE_ENDIAN
+	select HAVE_RUST if RUSTC_SUPPORTS_ARM64
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_KPROBES
@@ -270,6 +270,18 @@ config ARM64
 	help
 	  ARM 64-bit (AArch64) Linux support.
 
+config RUSTC_SUPPORTS_ARM64
+	def_bool y
+	depends on CPU_LITTLE_ENDIAN
+	# Shadow call stack is only supported on certain rustc versions.
+	#
+	# When using the UNWIND_PATCH_PAC_INTO_SCS option, rustc version 1.80+ is
+	# required due to use of the -Zfixed-x18 flag.
+	#
+	# Otherwise, rustc version 1.82+ is required due to use of the
+	# -Zsanitizer=shadow-call-stack flag.
+	depends on !SHADOW_CALL_STACK || RUSTC_VERSION >= 108200 || RUSTC_VERSION >= 108000 && UNWIND_PATCH_PAC_INTO_SCS
+
 config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
 	def_bool CC_IS_CLANG
 	# https://github.com/ClangBuiltLinux/linux/issues/1507

arch/arm64/Makefile

@@ -57,9 +57,11 @@ KBUILD_AFLAGS	+= $(call cc-option,-mabi=lp64)
 ifneq ($(CONFIG_UNWIND_TABLES),y)
 KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables -fno-unwind-tables
 KBUILD_AFLAGS	+= -fno-asynchronous-unwind-tables -fno-unwind-tables
+KBUILD_RUSTFLAGS += -Cforce-unwind-tables=n
 else
 KBUILD_CFLAGS	+= -fasynchronous-unwind-tables
 KBUILD_AFLAGS	+= -fasynchronous-unwind-tables
+KBUILD_RUSTFLAGS += -Cforce-unwind-tables=y -Zuse-sync-unwind=n
 endif
 
 ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
@@ -114,6 +116,7 @@ endif
 
 ifeq ($(CONFIG_SHADOW_CALL_STACK), y)
 KBUILD_CFLAGS	+= -ffixed-x18
+KBUILD_RUSTFLAGS += -Zfixed-x18
 endif
 
 ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)

arch/riscv/Kconfig

@@ -177,7 +177,7 @@ config RISCV
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RETHOOK if !XIP_KERNEL
 	select HAVE_RSEQ
-	select HAVE_RUST if 64BIT
+	select HAVE_RUST if RUSTC_SUPPORTS_RISCV
 	select HAVE_SAMPLE_FTRACE_DIRECT
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
 	select HAVE_STACKPROTECTOR
@@ -209,6 +209,13 @@ config RISCV
 	select USER_STACKTRACE_SUPPORT
 	select ZONE_DMA32 if 64BIT
 
+config RUSTC_SUPPORTS_RISCV
+	def_bool y
+	depends on 64BIT
+	# Shadow call stack requires rustc version 1.82+ due to use of the
+	# -Zsanitizer=shadow-call-stack flag.
+	depends on !SHADOW_CALL_STACK || RUSTC_VERSION >= 108200
+
 config CLANG_SUPPORTS_DYNAMIC_FTRACE
 	def_bool CC_IS_CLANG
 	# https://github.com/ClangBuiltLinux/linux/issues/1817

arch/x86/Makefile

@@ -24,11 +24,15 @@ RETPOLINE_CFLAGS	+= $(call cc-option,-mindirect-branch-cs-prefix)
 
 ifdef CONFIG_MITIGATION_RETHUNK
 RETHUNK_CFLAGS		:= -mfunction-return=thunk-extern
+RETHUNK_RUSTFLAGS	:= -Zfunction-return=thunk-extern
 RETPOLINE_CFLAGS	+= $(RETHUNK_CFLAGS)
+RETPOLINE_RUSTFLAGS	+= $(RETHUNK_RUSTFLAGS)
 endif
 
 export RETHUNK_CFLAGS
+export RETHUNK_RUSTFLAGS
 export RETPOLINE_CFLAGS
+export RETPOLINE_RUSTFLAGS
 export RETPOLINE_VDSO_CFLAGS
 
 # For gcc stack alignment is specified with -mpreferred-stack-boundary,
@@ -218,9 +222,10 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
 # Avoid indirect branches in kernel to deal with Spectre
 ifdef CONFIG_MITIGATION_RETPOLINE
   KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
+  KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS)
   # Additionally, avoid generating expensive indirect jumps which
   # are subject to retpolines for small number of switch cases.
-  # clang turns off jump table generation by default when under
+  # LLVM turns off jump table generation by default when under
   # retpoline builds, however, gcc does not for x86. This has
   # only been fixed starting from gcc stable version 8.4.0 and
   # onwards, but not for older ones. See gcc bug #86952.
@@ -237,6 +242,10 @@ ifdef CONFIG_CALL_PADDING
 PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
 KBUILD_CFLAGS += $(PADDING_CFLAGS)
 export PADDING_CFLAGS
+
+PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
+KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS)
+export PADDING_RUSTFLAGS
 endif
 
 KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)

init/Kconfig

@@ -60,6 +60,13 @@ config LLD_VERSION
 	default $(ld-version) if LD_IS_LLD
 	default 0
 
+config RUSTC_VERSION
+	int
+	default $(shell,$(srctree)/scripts/rustc-version.sh $(RUSTC))
+	help
+	  It does not depend on `RUST` since that one may need to use the version
+	  in a `depends on`.
+
 config RUST_IS_AVAILABLE
 	def_bool $(success,$(srctree)/scripts/rust_is_available.sh)
 	help
@@ -1935,12 +1942,14 @@ config RUST
 	bool "Rust support"
 	depends on HAVE_RUST
 	depends on RUST_IS_AVAILABLE
-	depends on !CFI_CLANG
 	depends on !MODVERSIONS
-	depends on !GCC_PLUGINS
+	depends on !GCC_PLUGIN_RANDSTRUCT
 	depends on !RANDSTRUCT
-	depends on !SHADOW_CALL_STACK
 	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
+	depends on !CFI_CLANG || RUSTC_VERSION >= 107900 && $(cc-option,-fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers)
+	select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG
+	depends on !CALL_PADDING || RUSTC_VERSION >= 108000
+	depends on !KASAN_SW_TAGS
 	help
 	  Enables Rust support in the kernel.
 
@@ -1957,7 +1966,9 @@ config RUST
 config RUSTC_VERSION_TEXT
 	string
 	depends on RUST
-	default "$(shell,$(RUSTC) --version 2>/dev/null)"
+	default "$(RUSTC_VERSION_TEXT)"
+	help
+	  See `CC_VERSION_TEXT`.
 
 config BINDGEN_VERSION_TEXT
 	string

mm/kasan/Makefile

@@ -44,7 +44,8 @@ ifndef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
 CFLAGS_KASAN_TEST += -fno-builtin
 endif
 
-CFLAGS_kasan_test.o := $(CFLAGS_KASAN_TEST)
+CFLAGS_kasan_test_c.o := $(CFLAGS_KASAN_TEST)
+RUSTFLAGS_kasan_test_rust.o := $(RUSTFLAGS_KASAN)
 CFLAGS_kasan_test_module.o := $(CFLAGS_KASAN_TEST)
 
 obj-y := common.o report.o
@@ -52,5 +53,10 @@ obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quaran
 obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o tags.o report_tags.o
 obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o tags.o report_tags.o
 
+kasan_test-objs := kasan_test_c.o
+ifdef CONFIG_RUST
+	kasan_test-objs += kasan_test_rust.o
+endif
+
 obj-$(CONFIG_KASAN_KUNIT_TEST) += kasan_test.o
 obj-$(CONFIG_KASAN_MODULE_TEST) += kasan_test_module.o

mm/kasan/kasan.h

@@ -555,6 +555,12 @@ static inline bool kasan_arch_is_ready(void)	{ return true; }
 void kasan_kunit_test_suite_start(void);
 void kasan_kunit_test_suite_end(void);
 
+#ifdef CONFIG_RUST
+char kasan_test_rust_uaf(void);
+#else
+static inline char kasan_test_rust_uaf(void) { return '\0'; }
+#endif
+
 #else /* CONFIG_KASAN_KUNIT_TEST */
 
 static inline void kasan_kunit_test_suite_start(void) { }

mm/kasan/kasan_test.c → mm/kasan/kasan_test_c.c

@@ -1944,6 +1944,16 @@ static void match_all_mem_tag(struct kunit *test)
 	kfree(ptr);
 }
 
+/*
+ * Check that Rust performing a use-after-free using `unsafe` is detected.
+ * This is a smoke test to make sure that Rust is being sanitized properly.
+ */
+static void rust_uaf(struct kunit *test)
+{
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_RUST);
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_test_rust_uaf());
+}
+
 static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kmalloc_oob_right),
 	KUNIT_CASE(kmalloc_oob_left),
@@ -2017,6 +2027,7 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(match_all_not_assigned),
 	KUNIT_CASE(match_all_ptr_tag),
 	KUNIT_CASE(match_all_mem_tag),
+	KUNIT_CASE(rust_uaf),
 	{}
 };
 

mm/kasan/kasan_test_rust.rs

+// SPDX-License-Identifier: GPL-2.0
+
+//! Helper crate for KASAN testing.
+//!
+//! Provides behavior to check the sanitization of Rust code.
+
+use core::ptr::addr_of_mut;
+use kernel::prelude::*;
+
+/// Trivial UAF - allocate a big vector, grab a pointer partway through,
+/// drop the vector, and touch it.
+#[no_mangle]
+pub extern "C" fn kasan_test_rust_uaf() -> u8 {
+    let mut v: Vec<u8> = Vec::new();
+    for _ in 0..4096 {
+        v.push(0x42, GFP_KERNEL).unwrap();
+    }
+    let ptr: *mut u8 = addr_of_mut!(v[2048]);
+    drop(v);
+    unsafe { *ptr }
+}

rust/Makefile

@@ -8,16 +8,16 @@ always-$(CONFIG_RUST) += exports_core_generated.h
 
 # Missing prototypes are expected in the helpers since these are exported
 # for Rust only, thus there is no header nor prototypes.
-obj-$(CONFIG_RUST) += helpers.o
-CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations
+obj-$(CONFIG_RUST) += helpers/helpers.o
+CFLAGS_REMOVE_helpers/helpers.o = -Wmissing-prototypes -Wmissing-declarations
 
 always-$(CONFIG_RUST) += libmacros.so
 no-clean-files += libmacros.so
 
 always-$(CONFIG_RUST) += bindings/bindings_generated.rs bindings/bindings_helpers_generated.rs
 obj-$(CONFIG_RUST) += alloc.o bindings.o kernel.o
-always-$(CONFIG_RUST) += exports_alloc_generated.h exports_bindings_generated.h \
-    exports_kernel_generated.h
+always-$(CONFIG_RUST) += exports_alloc_generated.h exports_helpers_generated.h \
+    exports_bindings_generated.h exports_kernel_generated.h
 
 always-$(CONFIG_RUST) += uapi/uapi_generated.rs
 obj-$(CONFIG_RUST) += uapi.o
@@ -63,6 +63,7 @@ quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
 	OBJTREE=$(abspath $(objtree)) \
 	$(RUSTDOC) $(if $(rustdoc_host),$(rust_common_flags),$(rust_flags)) \
 		$(rustc_target_flags) -L$(objtree)/$(obj) \
+		-Zunstable-options --generate-link-to-definition \
 		--output $(rustdoc_output) \
 		--crate-name $(subst rustdoc-,,$@) \
 		$(if $(rustdoc_host),,--sysroot=/dev/null) \
@@ -270,7 +271,7 @@ quiet_cmd_bindgen = BINDGEN $@
       cmd_bindgen = \
 	$(BINDGEN) $< $(bindgen_target_flags) \
 		--use-core --with-derive-default --ctypes-prefix core::ffi --no-layout-tests \
-		--no-debug '.*' \
+		--no-debug '.*' --enable-function-attribute-detection \
 		-o $@ -- $(bindgen_c_flags_final) -DMODULE \
 		$(bindgen_target_cflags) $(bindgen_target_extra)
 
@@ -299,13 +300,13 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \
     -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; \
     sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/#[link_name="rust_helper_\1"]\n    pub fn \1/g' $@
-$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers.c FORCE
+$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers/helpers.c FORCE
 	$(call if_changed_dep,bindgen)
 
 quiet_cmd_exports = EXPORTS $@
       cmd_exports = \
 	$(NM) -p --defined-only $< \
-		| awk '/ (T|R|D|B) / {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$3}' > $@
+		| awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$3}' > $@
 
 $(obj)/exports_core_generated.h: $(obj)/core.o FORCE
 	$(call if_changed,exports)
@@ -313,6 +314,18 @@ $(obj)/exports_core_generated.h: $(obj)/core.o FORCE
 $(obj)/exports_alloc_generated.h: $(obj)/alloc.o FORCE
 	$(call if_changed,exports)
 
+# Even though Rust kernel modules should never use the bindings directly,
+# symbols from the `bindings` crate and the C helpers need to be exported
+# because Rust generics and inlined functions may not get their code generated
+# in the crate where they are defined. Other helpers, called from non-inline
+# functions, may not be exported, in principle. However, in general, the Rust
+# compiler does not guarantee codegen will be performed for a non-inline
+# function either. Therefore, we export all symbols from helpers and bindings.
+# In the future, this may be revisited to reduce the number of exports after
+# the compiler is informed about the places codegen is required.
+$(obj)/exports_helpers_generated.h: $(obj)/helpers/helpers.o FORCE
+	$(call if_changed,exports)
+
 $(obj)/exports_bindings_generated.h: $(obj)/bindings.o FORCE
 	$(call if_changed,exports)
 
@@ -329,9 +342,7 @@ quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
 		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<
 
 # Procedural macros can only be used with the `rustc` that compiled it.
-# Therefore, to get `libmacros.so` automatically recompiled when the compiler
-# version changes, we add `core.o` as a dependency (even if it is not needed).
-$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE
+$(obj)/libmacros.so: $(src)/macros/lib.rs FORCE
 	+$(call if_changed_dep,rustc_procmacro)
 
 quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@
@@ -344,7 +355,8 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 		--crate-type rlib -L$(objtree)/$(obj) \
 		--crate-name $(patsubst %.o,%,$(notdir $@)) $< \
 		--sysroot=/dev/null \
-	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
+	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@) \
+	$(cmd_objtool)
 
 rust-analyzer:
 	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
@@ -366,44 +378,50 @@ ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),)
 		__ashlti3 __lshrti3
 endif
 
+define rule_rustc_library
+	$(call cmd_and_fixdep,rustc_library)
+	$(call cmd,gen_objtooldep)
+endef
+
 $(obj)/core.o: private skip_clippy = 1
 $(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: $(RUST_LIB_SRC)/core/src/lib.rs FORCE
-	+$(call if_changed_dep,rustc_library)
+$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs \
+    $(wildcard $(objtree)/include/config/RUSTC_VERSION_TEXT) FORCE
+	+$(call if_changed_rule,rustc_library)
 ifneq ($(or $(CONFIG_X86_64),$(CONFIG_X86_32)),)
 $(obj)/core.o: scripts/target.json
 endif
 
 $(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'
 $(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
-	+$(call if_changed_dep,rustc_library)
+	+$(call if_changed_rule,rustc_library)
 
 $(obj)/alloc.o: private skip_clippy = 1
 $(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)
+	+$(call if_changed_rule,rustc_library)
 
 $(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE
-	+$(call if_changed_dep,rustc_library)
+	+$(call if_changed_rule,rustc_library)
 
 $(obj)/bindings.o: $(src)/bindings/lib.rs \
     $(obj)/compiler_builtins.o \
     $(obj)/bindings/bindings_generated.rs \
     $(obj)/bindings/bindings_helpers_generated.rs FORCE
-	+$(call if_changed_dep,rustc_library)
+	+$(call if_changed_rule,rustc_library)
 
 $(obj)/uapi.o: $(src)/uapi/lib.rs \
     $(obj)/compiler_builtins.o \
     $(obj)/uapi/uapi_generated.rs FORCE
-	+$(call if_changed_dep,rustc_library)
+	+$(call if_changed_rule,rustc_library)
 
 $(obj)/kernel.o: private rustc_target_flags = --extern alloc \
     --extern build_error --extern macros --extern bindings --extern uapi
 $(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \
     $(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE
-	+$(call if_changed_dep,rustc_library)
+	+$(call if_changed_rule,rustc_library)
 
 endif # CONFIG_RUST

rust/bindings/bindings_helper.h

@@ -7,8 +7,8 @@
  */
 
 #include <kunit/test.h>
-#include <linux/blk_types.h>
 #include <linux/blk-mq.h>
+#include <linux/blk_types.h>
 #include <linux/blkdev.h>
 #include <linux/errname.h>
 #include <linux/ethtool.h>

rust/exports.c

@@ -17,6 +17,7 @@
 
 #include "exports_core_generated.h"
 #include "exports_alloc_generated.h"
+#include "exports_helpers_generated.h"
 #include "exports_bindings_generated.h"
 #include "exports_kernel_generated.h"
 

rust/helpers.c

-// SPDX-License-Identifier: GPL-2.0
-/*
- * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
- * cannot be called either. This file explicitly creates functions ("helpers")
- * that wrap those so that they can be called from Rust.
- *
- * Even though Rust kernel modules should never use the bindings directly, some
- * of these helpers need to be exported because Rust generics and inlined
- * functions may not get their code generated in the crate where they are
- * defined. Other helpers, called from non-inline functions, may not be
- * exported, in principle. However, in general, the Rust compiler does not
- * guarantee codegen will be performed for a non-inline function either.
- * Therefore, this file exports all the helpers. In the future, this may be
- * revisited to reduce the number of exports after the compiler is informed
- * about the places codegen is required.
- *
- * All symbols are exported as GPL-only to guarantee no GPL-only feature is
- * accidentally exposed.
- *
- * Sorted alphabetically.
- */
-
-#include <kunit/test-bug.h>
-#include <linux/bug.h>
-#include <linux/build_bug.h>
-#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>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/wait.h>
-#include <linux/workqueue.h>
-
-__noreturn void rust_helper_BUG(void)
-{
-	BUG();
-}
-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);
-}
-EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
-
-void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
-				  struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_SPINLOCK
-	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
-#else
-	spin_lock_init(lock);
-#endif
-}
-EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
-
-void rust_helper_spin_lock(spinlock_t *lock)
-{
-	spin_lock(lock);
-}
-EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
-
-void rust_helper_spin_unlock(spinlock_t *lock)
-{
-	spin_unlock(lock);
-}
-EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
-
-void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
-{
-	init_wait(wq_entry);
-}
-EXPORT_SYMBOL_GPL(rust_helper_init_wait);
-
-int rust_helper_signal_pending(struct task_struct *t)
-{
-	return signal_pending(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)
-{
-	return kmap_local_page(page);
-}
-EXPORT_SYMBOL_GPL(rust_helper_kmap_local_page);
-
-void rust_helper_kunmap_local(const void *addr)
-{
-	kunmap_local(addr);
-}
-EXPORT_SYMBOL_GPL(rust_helper_kunmap_local);
-
-refcount_t rust_helper_REFCOUNT_INIT(int n)
-{
-	return (refcount_t)REFCOUNT_INIT(n);
-}
-EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
-
-void rust_helper_refcount_inc(refcount_t *r)
-{
-	refcount_inc(r);
-}
-EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
-
-bool rust_helper_refcount_dec_and_test(refcount_t *r)
-{
-	return refcount_dec_and_test(r);
-}
-EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
-
-__force void *rust_helper_ERR_PTR(long err)
-{
-	return ERR_PTR(err);
-}
-EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
-
-bool rust_helper_IS_ERR(__force const void *ptr)
-{
-	return IS_ERR(ptr);
-}
-EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
-
-long rust_helper_PTR_ERR(__force const void *ptr)
-{
-	return PTR_ERR(ptr);
-}
-EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
-
-const char *rust_helper_errname(int err)
-{
-	return errname(err);
-}
-EXPORT_SYMBOL_GPL(rust_helper_errname);
-
-struct task_struct *rust_helper_get_current(void)
-{
-	return current;
-}
-EXPORT_SYMBOL_GPL(rust_helper_get_current);
-
-void rust_helper_get_task_struct(struct task_struct *t)
-{
-	get_task_struct(t);
-}
-EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
-
-void rust_helper_put_task_struct(struct task_struct *t)
-{
-	put_task_struct(t);
-}
-EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
-
-struct kunit *rust_helper_kunit_get_current_test(void)
-{
-	return kunit_get_current_test();
-}
-EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
-
-void rust_helper_init_work_with_key(struct work_struct *work, work_func_t func,
-				    bool onstack, const char *name,
-				    struct lock_class_key *key)
-{
-	__init_work(work, onstack);
-	work->data = (atomic_long_t)WORK_DATA_INIT();
-	lockdep_init_map(&work->lockdep_map, name, key, 0);
-	INIT_LIST_HEAD(&work->entry);
-	work->func = func;
-}
-EXPORT_SYMBOL_GPL(rust_helper_init_work_with_key);
-
-void * __must_check __realloc_size(2)
-rust_helper_krealloc(const void *objp, size_t new_size, gfp_t flags)
-{
-	return krealloc(objp, new_size, flags);
-}
-EXPORT_SYMBOL_GPL(rust_helper_krealloc);
-
-/*
- * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
- * use it in contexts where Rust expects a `usize` like slice (array) indices.
- * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
- * pointer) but not necessarily the same as `size_t` (can hold the size of any
- * single object). Most modern platforms use the same concrete integer type for
- * both of them, but in case we find ourselves on a platform where
- * that's not true, fail early instead of risking ABI or
- * integer-overflow issues.
- *
- * If your platform fails this assertion, it means that you are in
- * danger of integer-overflow bugs (even if you attempt to add
- * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
- * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
- * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
- */
-static_assert(
-	sizeof(size_t) == sizeof(uintptr_t) &&
-	__alignof__(size_t) == __alignof__(uintptr_t),
-	"Rust code expects C `size_t` to match Rust `usize`"
-);
-
-// This will soon be moved to a separate file, so no need to merge with above.
-#include <linux/blk-mq.h>
-#include <linux/blkdev.h>
-
-void *rust_helper_blk_mq_rq_to_pdu(struct request *rq)
-{
-	return blk_mq_rq_to_pdu(rq);
-}
-EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_to_pdu);
-
-struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
-{
-	return blk_mq_rq_from_pdu(pdu);
-}
-EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_from_pdu);

rust/helpers/blk.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/blk-mq.h>
+#include <linux/blkdev.h>
+
+void *rust_helper_blk_mq_rq_to_pdu(struct request *rq)
+{
+	return blk_mq_rq_to_pdu(rq);
+}
+
+struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
+{
+	return blk_mq_rq_from_pdu(pdu);
+}

rust/helpers/bug.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bug.h>
+
+__noreturn void rust_helper_BUG(void)
+{
+	BUG();
+}

rust/helpers/build_assert.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/build_bug.h>
+
+/*
+ * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
+ * use it in contexts where Rust expects a `usize` like slice (array) indices.
+ * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
+ * pointer) but not necessarily the same as `size_t` (can hold the size of any
+ * single object). Most modern platforms use the same concrete integer type for
+ * both of them, but in case we find ourselves on a platform where
+ * that's not true, fail early instead of risking ABI or
+ * integer-overflow issues.
+ *
+ * If your platform fails this assertion, it means that you are in
+ * danger of integer-overflow bugs (even if you attempt to add
+ * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
+ * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
+ */
+static_assert(
+	sizeof(size_t) == sizeof(uintptr_t) &&
+	__alignof__(size_t) == __alignof__(uintptr_t),
+	"Rust code expects C `size_t` to match Rust `usize`"
+);

rust/helpers/build_bug.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/errname.h>
+
+const char *rust_helper_errname(int err)
+{
+	return errname(err);
+}

rust/helpers/err.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/err.h>
+#include <linux/export.h>
+
+__force void *rust_helper_ERR_PTR(long err)
+{
+	return ERR_PTR(err);
+}
+
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+	return IS_ERR(ptr);
+}
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+	return PTR_ERR(ptr);
+}

rust/helpers/helpers.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
+ * cannot be called either. This file explicitly creates functions ("helpers")
+ * that wrap those so that they can be called from Rust.
+ *
+ * Sorted alphabetically.
+ */
+
+#include "blk.c"
+#include "bug.c"
+#include "build_assert.c"
+#include "build_bug.c"
+#include "err.c"
+#include "kunit.c"
+#include "mutex.c"
+#include "page.c"
+#include "rbtree.c"
+#include "refcount.c"
+#include "signal.c"
+#include "slab.c"
+#include "spinlock.c"
+#include "task.c"
+#include "uaccess.c"
+#include "wait.c"
+#include "workqueue.c"

rust/helpers/kunit.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <kunit/test-bug.h>
+#include <linux/export.h>
+
+struct kunit *rust_helper_kunit_get_current_test(void)
+{
+	return kunit_get_current_test();
+}

rust/helpers/mutex.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/mutex.h>
+
+void rust_helper_mutex_lock(struct mutex *lock)
+{
+	mutex_lock(lock);
+}

rust/helpers/page.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+
+struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+	return alloc_pages(gfp_mask, order);
+}
+
+void *rust_helper_kmap_local_page(struct page *page)
+{
+	return kmap_local_page(page);
+}
+
+void rust_helper_kunmap_local(const void *addr)
+{
+	kunmap_local(addr);
+}

rust/helpers/rbtree.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/rbtree.h>
+
+void rust_helper_rb_link_node(struct rb_node *node, struct rb_node *parent,
+			      struct rb_node **rb_link)
+{
+	rb_link_node(node, parent, rb_link);
+}

rust/helpers/refcount.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/refcount.h>
+
+refcount_t rust_helper_REFCOUNT_INIT(int n)
+{
+	return (refcount_t)REFCOUNT_INIT(n);
+}
+
+void rust_helper_refcount_inc(refcount_t *r)
+{
+	refcount_inc(r);
+}
+
+bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+	return refcount_dec_and_test(r);
+}

rust/helpers/signal.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/sched/signal.h>
+
+int rust_helper_signal_pending(struct task_struct *t)
+{
+	return signal_pending(t);
+}

rust/helpers/slab.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/slab.h>
+
+void * __must_check __realloc_size(2)
+rust_helper_krealloc(const void *objp, size_t new_size, gfp_t flags)
+{
+	return krealloc(objp, new_size, flags);
+}

rust/helpers/spinlock.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/spinlock.h>
+
+void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
+				  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
+#else
+	spin_lock_init(lock);
+#endif
+}
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+}
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+	spin_unlock(lock);
+}

rust/helpers/task.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/sched/task.h>
+
+struct task_struct *rust_helper_get_current(void)
+{
+	return current;
+}
+
+void rust_helper_get_task_struct(struct task_struct *t)
+{
+	get_task_struct(t);
+}
+
+void rust_helper_put_task_struct(struct task_struct *t)
+{
+	put_task_struct(t);
+}

rust/helpers/uaccess.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/uaccess.h>
+
+unsigned long rust_helper_copy_from_user(void *to, const void __user *from,
+					 unsigned long n)
+{
+	return copy_from_user(to, from, n);
+}
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from,
+				       unsigned long n)
+{
+	return copy_to_user(to, from, n);
+}

rust/helpers/wait.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/wait.h>
+
+void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
+{
+	init_wait(wq_entry);
+}

rust/helpers/workqueue.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/workqueue.h>
+
+void rust_helper_init_work_with_key(struct work_struct *work, work_func_t func,
+				    bool onstack, const char *name,
+				    struct lock_class_key *key)
+{
+	__init_work(work, onstack);
+	work->data = (atomic_long_t)WORK_DATA_INIT();
+	lockdep_init_map(&work->lockdep_map, name, key, 0);
+	INIT_LIST_HEAD(&work->entry);
+	work->func = func;
+}

rust/kernel/alloc/box_ext.rs

@@ -4,7 +4,7 @@
 
 use super::{AllocError, Flags};
 use alloc::boxed::Box;
-use core::mem::MaybeUninit;
+use core::{mem::MaybeUninit, ptr, result::Result};
 
 /// Extensions to [`Box`].
 pub trait BoxExt<T>: Sized {
@@ -17,6 +17,24 @@ pub trait BoxExt<T>: Sized {
     ///
     /// The allocation may fail, in which case an error is returned.
     fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError>;
+
+    /// Drops the contents, but keeps the allocation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::alloc::{flags, box_ext::BoxExt};
+    /// let value = Box::new([0; 32], flags::GFP_KERNEL)?;
+    /// assert_eq!(*value, [0; 32]);
+    /// let mut value = Box::drop_contents(value);
+    /// // Now we can re-use `value`:
+    /// value.write([1; 32]);
+    /// // SAFETY: We just wrote to it.
+    /// let value = unsafe { value.assume_init() };
+    /// assert_eq!(*value, [1; 32]);
+    /// # Ok::<(), Error>(())
+    /// ```
+    fn drop_contents(this: Self) -> Box<MaybeUninit<T>>;
 }
 
 impl<T> BoxExt<T> for Box<T> {
@@ -55,4 +73,17 @@ fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
         // zero-sized types, we use `NonNull::dangling`.
         Ok(unsafe { Box::from_raw(ptr) })
     }
+
+    fn drop_contents(this: Self) -> Box<MaybeUninit<T>> {
+        let ptr = Box::into_raw(this);
+        // SAFETY: `ptr` is valid, because it came from `Box::into_raw`.
+        unsafe { ptr::drop_in_place(ptr) };
+
+        // CAST: `MaybeUninit<T>` is a transparent wrapper of `T`.
+        let ptr = ptr.cast::<MaybeUninit<T>>();
+
+        // SAFETY: `ptr` is valid for writes, because it came from `Box::into_raw` and it is valid for
+        // reads, since the pointer came from `Box::into_raw` and the type is `MaybeUninit<T>`.
+        unsafe { Box::from_raw(ptr) }
+    }
 }

rust/kernel/error.rs

@@ -135,8 +135,11 @@ pub(crate) fn to_blk_status(self) -> bindings::blk_status_t {
     /// Returns the error encoded as a pointer.
     #[allow(dead_code)]
     pub(crate) fn to_ptr<T>(self) -> *mut T {
+        #[cfg_attr(target_pointer_width = "32", allow(clippy::useless_conversion))]
         // SAFETY: `self.0` is a valid error due to its invariant.
-        unsafe { bindings::ERR_PTR(self.0.into()) as *mut _ }
+        unsafe {
+            bindings::ERR_PTR(self.0.into()) as *mut _
+        }
     }
 
     /// Returns a string representing the error, if one exists.

rust/kernel/init.rs

@@ -213,6 +213,7 @@
 use crate::{
     alloc::{box_ext::BoxExt, AllocError, Flags},
     error::{self, Error},
+    sync::Arc,
     sync::UniqueArc,
     types::{Opaque, ScopeGuard},
 };
@@ -742,6 +743,74 @@ macro_rules! try_init {
     };
 }
 
+/// Asserts that a field on a struct using `#[pin_data]` is marked with `#[pin]` ie. that it is
+/// structurally pinned.
+///
+/// # Example
+///
+/// This will succeed:
+/// ```
+/// use kernel::assert_pinned;
+/// #[pin_data]
+/// struct MyStruct {
+///     #[pin]
+///     some_field: u64,
+/// }
+///
+/// assert_pinned!(MyStruct, some_field, u64);
+/// ```
+///
+/// This will fail:
+// TODO: replace with `compile_fail` when supported.
+/// ```ignore
+/// use kernel::assert_pinned;
+/// #[pin_data]
+/// struct MyStruct {
+///     some_field: u64,
+/// }
+///
+/// assert_pinned!(MyStruct, some_field, u64);
+/// ```
+///
+/// Some uses of the macro may trigger the `can't use generic parameters from outer item` error. To
+/// work around this, you may pass the `inline` parameter to the macro. The `inline` parameter can
+/// only be used when the macro is invoked from a function body.
+/// ```
+/// use kernel::assert_pinned;
+/// #[pin_data]
+/// struct Foo<T> {
+///     #[pin]
+///     elem: T,
+/// }
+///
+/// impl<T> Foo<T> {
+///     fn project(self: Pin<&mut Self>) -> Pin<&mut T> {
+///         assert_pinned!(Foo<T>, elem, T, inline);
+///
+///         // SAFETY: The field is structurally pinned.
+///         unsafe { self.map_unchecked_mut(|me| &mut me.elem) }
+///     }
+/// }
+/// ```
+#[macro_export]
+macro_rules! assert_pinned {
+    ($ty:ty, $field:ident, $field_ty:ty, inline) => {
+        let _ = move |ptr: *mut $field_ty| {
+            // SAFETY: This code is unreachable.
+            let data = unsafe { <$ty as $crate::init::__internal::HasPinData>::__pin_data() };
+            let init = $crate::init::__internal::AlwaysFail::<$field_ty>::new();
+            // SAFETY: This code is unreachable.
+            unsafe { data.$field(ptr, init) }.ok();
+        };
+    };
+
+    ($ty:ty, $field:ident, $field_ty:ty) => {
+        const _: () = {
+            $crate::assert_pinned!($ty, $field, $field_ty, inline);
+        };
+    };
+}
+
 /// A pin-initializer for the type `T`.
 ///
 /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can
@@ -1107,11 +1176,17 @@ unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
 
 /// Smart pointer that can initialize memory in-place.
 pub trait InPlaceInit<T>: Sized {
+    /// Pinned version of `Self`.
+    ///
+    /// If a type already implicitly pins its pointee, `Pin<Self>` is unnecessary. In this case use
+    /// `Self`, otherwise just use `Pin<Self>`.
+    type PinnedSelf;
+
     /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this
     /// type.
     ///
     /// If `T: !Unpin` it will not be able to move afterwards.
-    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>, E>
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
     where
         E: From<AllocError>;
 
@@ -1119,7 +1194,7 @@ fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>,
     /// type.
     ///
     /// If `T: !Unpin` it will not be able to move afterwards.
-    fn pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> error::Result<Pin<Self>>
+    fn pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> error::Result<Self::PinnedSelf>
     where
         Error: From<E>,
     {
@@ -1148,19 +1223,35 @@ fn init<E>(init: impl Init<T, E>, flags: Flags) -> error::Result<Self>
     }
 }
 
+impl<T> InPlaceInit<T> for Arc<T> {
+    type PinnedSelf = Self;
+
+    #[inline]
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
+    where
+        E: From<AllocError>,
+    {
+        UniqueArc::try_pin_init(init, flags).map(|u| u.into())
+    }
+
+    #[inline]
+    fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
+    where
+        E: From<AllocError>,
+    {
+        UniqueArc::try_init(init, flags).map(|u| u.into())
+    }
+}
+
 impl<T> InPlaceInit<T> for Box<T> {
+    type PinnedSelf = Pin<Self>;
+
     #[inline]
-    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>, E>
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
     where
         E: From<AllocError>,
     {
-        let mut this = <Box<_> as BoxExt<_>>::new_uninit(flags)?;
-        let slot = this.as_mut_ptr();
-        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
-        // slot is valid and will not be moved, because we pin it later.
-        unsafe { init.__pinned_init(slot)? };
-        // SAFETY: All fields have been initialized.
-        Ok(unsafe { this.assume_init() }.into())
+        <Box<_> as BoxExt<_>>::new_uninit(flags)?.write_pin_init(init)
     }
 
     #[inline]
@@ -1168,29 +1259,19 @@ fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
     where
         E: From<AllocError>,
     {
-        let mut this = <Box<_> as BoxExt<_>>::new_uninit(flags)?;
-        let slot = this.as_mut_ptr();
-        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
-        // slot is valid.
-        unsafe { init.__init(slot)? };
-        // SAFETY: All fields have been initialized.
-        Ok(unsafe { this.assume_init() })
+        <Box<_> as BoxExt<_>>::new_uninit(flags)?.write_init(init)
     }
 }
 
 impl<T> InPlaceInit<T> for UniqueArc<T> {
+    type PinnedSelf = Pin<Self>;
+
     #[inline]
-    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>, E>
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
     where
         E: From<AllocError>,
     {
-        let mut this = UniqueArc::new_uninit(flags)?;
-        let slot = this.as_mut_ptr();
-        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
-        // slot is valid and will not be moved, because we pin it later.
-        unsafe { init.__pinned_init(slot)? };
-        // SAFETY: All fields have been initialized.
-        Ok(unsafe { this.assume_init() }.into())
+        UniqueArc::new_uninit(flags)?.write_pin_init(init)
     }
 
     #[inline]
@@ -1198,13 +1279,67 @@ fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
     where
         E: From<AllocError>,
     {
-        let mut this = UniqueArc::new_uninit(flags)?;
-        let slot = this.as_mut_ptr();
+        UniqueArc::new_uninit(flags)?.write_init(init)
+    }
+}
+
+/// Smart pointer containing uninitialized memory and that can write a value.
+pub trait InPlaceWrite<T> {
+    /// The type `Self` turns into when the contents are initialized.
+    type Initialized;
+
+    /// Use the given initializer to write a value into `self`.
+    ///
+    /// Does not drop the current value and considers it as uninitialized memory.
+    fn write_init<E>(self, init: impl Init<T, E>) -> Result<Self::Initialized, E>;
+
+    /// Use the given pin-initializer to write a value into `self`.
+    ///
+    /// Does not drop the current value and considers it as uninitialized memory.
+    fn write_pin_init<E>(self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E>;
+}
+
+impl<T> InPlaceWrite<T> for Box<MaybeUninit<T>> {
+    type Initialized = Box<T>;
+
+    fn write_init<E>(mut self, init: impl Init<T, E>) -> Result<Self::Initialized, E> {
+        let slot = self.as_mut_ptr();
         // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
         // slot is valid.
         unsafe { init.__init(slot)? };
         // SAFETY: All fields have been initialized.
-        Ok(unsafe { this.assume_init() })
+        Ok(unsafe { self.assume_init() })
+    }
+
+    fn write_pin_init<E>(mut self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E> {
+        let slot = self.as_mut_ptr();
+        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+        // slot is valid and will not be moved, because we pin it later.
+        unsafe { init.__pinned_init(slot)? };
+        // SAFETY: All fields have been initialized.
+        Ok(unsafe { self.assume_init() }.into())
+    }
+}
+
+impl<T> InPlaceWrite<T> for UniqueArc<MaybeUninit<T>> {
+    type Initialized = UniqueArc<T>;
+
+    fn write_init<E>(mut self, init: impl Init<T, E>) -> Result<Self::Initialized, E> {
+        let slot = self.as_mut_ptr();
+        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+        // slot is valid.
+        unsafe { init.__init(slot)? };
+        // SAFETY: All fields have been initialized.
+        Ok(unsafe { self.assume_init() })
+    }
+
+    fn write_pin_init<E>(mut self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E> {
+        let slot = self.as_mut_ptr();
+        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+        // slot is valid and will not be moved, because we pin it later.
+        unsafe { init.__pinned_init(slot)? };
+        // SAFETY: All fields have been initialized.
+        Ok(unsafe { self.assume_init() }.into())
     }
 }
 

rust/kernel/init/__internal.rs

@@ -228,3 +228,32 @@ pub unsafe fn new() -> Self {
         Self(())
     }
 }
+
+/// Initializer that always fails.
+///
+/// Used by [`assert_pinned!`].
+///
+/// [`assert_pinned!`]: crate::assert_pinned
+pub struct AlwaysFail<T: ?Sized> {
+    _t: PhantomData<T>,
+}
+
+impl<T: ?Sized> AlwaysFail<T> {
+    /// Creates a new initializer that always fails.
+    pub fn new() -> Self {
+        Self { _t: PhantomData }
+    }
+}
+
+impl<T: ?Sized> Default for AlwaysFail<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+// SAFETY: `__pinned_init` always fails, which is always okay.
+unsafe impl<T: ?Sized> PinInit<T, ()> for AlwaysFail<T> {
+    unsafe fn __pinned_init(self, _slot: *mut T) -> Result<(), ()> {
+        Err(())
+    }
+}

rust/kernel/lib.rs

@@ -38,12 +38,14 @@
 pub mod ioctl;
 #[cfg(CONFIG_KUNIT)]
 pub mod kunit;
+pub mod list;
 #[cfg(CONFIG_NET)]
 pub mod net;
 pub mod page;
 pub mod prelude;
 pub mod print;
 pub mod sizes;
+pub mod rbtree;
 mod static_assert;
 #[doc(hidden)]
 pub mod std_vendor;

rust/kernel/list/arc_field.rs

+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 Google LLC.
+
+//! A field that is exclusively owned by a [`ListArc`].
+//!
+//! This can be used to have reference counted struct where one of the reference counted pointers
+//! has exclusive access to a field of the struct.
+//!
+//! [`ListArc`]: crate::list::ListArc
+
+use core::cell::UnsafeCell;
+
+/// A field owned by a specific [`ListArc`].
+///
+/// [`ListArc`]: crate::list::ListArc
+pub struct ListArcField<T, const ID: u64 = 0> {
+    value: UnsafeCell<T>,
+}
+
+// SAFETY: If the inner type is thread-safe, then it's also okay for `ListArc` to be thread-safe.
+unsafe impl<T: Send + Sync, const ID: u64> Send for ListArcField<T, ID> {}
+// SAFETY: If the inner type is thread-safe, then it's also okay for `ListArc` to be thread-safe.
+unsafe impl<T: Send + Sync, const ID: u64> Sync for ListArcField<T, ID> {}
+
+impl<T, const ID: u64> ListArcField<T, ID> {
+    /// Creates a new `ListArcField`.
+    pub fn new(value: T) -> Self {
+        Self {
+            value: UnsafeCell::new(value),
+        }
+    }
+
+    /// Access the value when we have exclusive access to the `ListArcField`.
+    ///
+    /// This allows access to the field using an `UniqueArc` instead of a `ListArc`.
+    pub fn get_mut(&mut self) -> &mut T {
+        self.value.get_mut()
+    }
+
+    /// Unsafely assert that you have shared access to the `ListArc` for this field.
+    ///
+    /// # Safety
+    ///
+    /// The caller must have shared access to the `ListArc<ID>` containing the struct with this
+    /// field for the duration of the returned reference.
+    pub unsafe fn assert_ref(&self) -> &T {
+        // SAFETY: The caller has shared access to the `ListArc`, so they also have shared access
+        // to this field.
+        unsafe { &*self.value.get() }
+    }
+
+    /// Unsafely assert that you have mutable access to the `ListArc` for this field.
+    ///
+    /// # Safety
+    ///
+    /// The caller must have mutable access to the `ListArc<ID>` containing the struct with this
+    /// field for the duration of the returned reference.
+    #[allow(clippy::mut_from_ref)]
+    pub unsafe fn assert_mut(&self) -> &mut T {
+        // SAFETY: The caller has exclusive access to the `ListArc`, so they also have exclusive
+        // access to this field.
+        unsafe { &mut *self.value.get() }
+    }
+}
+
+/// Defines getters for a [`ListArcField`].
+#[macro_export]
+macro_rules! define_list_arc_field_getter {
+    ($pub:vis fn $name:ident(&self $(<$id:tt>)?) -> &$typ:ty { $field:ident }
+     $($rest:tt)*
+    ) => {
+        $pub fn $name<'a>(self: &'a $crate::list::ListArc<Self $(, $id)?>) -> &'a $typ {
+            let field = &(&**self).$field;
+            // SAFETY: We have a shared reference to the `ListArc`.
+            unsafe { $crate::list::ListArcField::<$typ $(, $id)?>::assert_ref(field) }
+        }
+
+        $crate::list::define_list_arc_field_getter!($($rest)*);
+    };
+
+    ($pub:vis fn $name:ident(&mut self $(<$id:tt>)?) -> &mut $typ:ty { $field:ident }
+     $($rest:tt)*
+    ) => {
+        $pub fn $name<'a>(self: &'a mut $crate::list::ListArc<Self $(, $id)?>) -> &'a mut $typ {
+            let field = &(&**self).$field;
+            // SAFETY: We have a mutable reference to the `ListArc`.
+            unsafe { $crate::list::ListArcField::<$typ $(, $id)?>::assert_mut(field) }
+        }
+
+        $crate::list::define_list_arc_field_getter!($($rest)*);
+    };
+
+    () => {};
+}
+pub use define_list_arc_field_getter;

rust/kernel/prelude.rs

@@ -37,6 +37,6 @@
 
 pub use super::{str::CStr, ThisModule};
 
-pub use super::init::{InPlaceInit, Init, PinInit};
+pub use super::init::{InPlaceInit, InPlaceWrite, Init, PinInit};
 
 pub use super::current;

rust/kernel/print.rs

@@ -4,7 +4,7 @@
 //!
 //! C header: [`include/linux/printk.h`](srctree/include/linux/printk.h)
 //!
-//! Reference: <https://www.kernel.org/doc/html/latest/core-api/printk-basics.html>
+//! Reference: <https://docs.kernel.org/core-api/printk-basics.html>
 
 use core::{
     ffi::{c_char, c_void},
@@ -197,7 +197,7 @@ macro_rules! print_macro (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_emerg`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_emerg
+/// [`pr_emerg`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_emerg
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -221,7 +221,7 @@ macro_rules! pr_emerg (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_alert`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_alert
+/// [`pr_alert`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_alert
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -245,7 +245,7 @@ macro_rules! pr_alert (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_crit`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_crit
+/// [`pr_crit`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_crit
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -269,7 +269,7 @@ macro_rules! pr_crit (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_err`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_err
+/// [`pr_err`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_err
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -293,7 +293,7 @@ macro_rules! pr_err (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_warn`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_warn
+/// [`pr_warn`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_warn
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -317,7 +317,7 @@ macro_rules! pr_warn (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_notice`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_notice
+/// [`pr_notice`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_notice
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -341,7 +341,7 @@ macro_rules! pr_notice (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_info`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_info
+/// [`pr_info`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_info
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -367,7 +367,7 @@ macro_rules! pr_info (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
-/// [`pr_debug`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_debug
+/// [`pr_debug`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_debug
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples
@@ -395,7 +395,7 @@ macro_rules! pr_debug (
 /// `alloc::format!` for information about the formatting syntax.
 ///
 /// [`pr_info!`]: crate::pr_info!
-/// [`pr_cont`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_cont
+/// [`pr_cont`]: https://docs.kernel.org/core-api/printk-basics.html#c.pr_cont
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
 /// # Examples

rust/kernel/std_vendor.rs

@@ -136,7 +136,7 @@
 ///
 /// [`std::dbg`]: https://doc.rust-lang.org/std/macro.dbg.html
 /// [`eprintln`]: https://doc.rust-lang.org/std/macro.eprintln.html
-/// [`printk`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html
+/// [`printk`]: https://docs.kernel.org/core-api/printk-basics.html
 /// [`pr_info`]: crate::pr_info!
 /// [`pr_debug`]: crate::pr_debug!
 #[macro_export]

rust/kernel/sync/arc.rs

@@ -12,12 +12,13 @@
 //! 2. It does not support weak references, which allows it to be half the size.
 //! 3. It saturates the reference count instead of aborting when it goes over a threshold.
 //! 4. It does not provide a `get_mut` method, so the ref counted object is pinned.
+//! 5. The object in [`Arc`] is pinned implicitly.
 //!
 //! [`Arc`]: https://doc.rust-lang.org/std/sync/struct.Arc.html
 
 use crate::{
     alloc::{box_ext::BoxExt, AllocError, Flags},
-    error::{self, Error},
+    bindings,
     init::{self, InPlaceInit, Init, PinInit},
     try_init,
     types::{ForeignOwnable, Opaque},
@@ -209,28 +210,6 @@ pub fn new(contents: T, flags: Flags) -> Result<Self, AllocError> {
         // `Arc` object.
         Ok(unsafe { Self::from_inner(Box::leak(inner).into()) })
     }
-
-    /// Use the given initializer to in-place initialize a `T`.
-    ///
-    /// If `T: !Unpin` it will not be able to move afterwards.
-    #[inline]
-    pub fn pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> error::Result<Self>
-    where
-        Error: From<E>,
-    {
-        UniqueArc::pin_init(init, flags).map(|u| u.into())
-    }
-
-    /// Use the given initializer to in-place initialize a `T`.
-    ///
-    /// This is equivalent to [`Arc<T>::pin_init`], since an [`Arc`] is always pinned.
-    #[inline]
-    pub fn init<E>(init: impl Init<T, E>, flags: Flags) -> error::Result<Self>
-    where
-        Error: From<E>,
-    {
-        UniqueArc::init(init, flags).map(|u| u.into())
-    }
 }
 
 impl<T: ?Sized> Arc<T> {

rust/kernel/types.rs

@@ -7,8 +7,9 @@
 use core::{
     cell::UnsafeCell,
     marker::{PhantomData, PhantomPinned},
-    mem::MaybeUninit,
+    mem::{ManuallyDrop, MaybeUninit},
     ops::{Deref, DerefMut},
+    pin::Pin,
     ptr::NonNull,
 };
 
@@ -26,7 +27,10 @@ pub trait ForeignOwnable: Sized {
 
     /// Converts a Rust-owned object to a foreign-owned one.
     ///
-    /// The foreign representation is a pointer to void.
+    /// The foreign representation is a pointer to void. There are no guarantees for this pointer.
+    /// For example, it might be invalid, dangling or pointing to uninitialized memory. Using it in
+    /// any way except for [`ForeignOwnable::from_foreign`], [`ForeignOwnable::borrow`],
+    /// [`ForeignOwnable::try_from_foreign`] can result in undefined behavior.
     fn into_foreign(self) -> *const core::ffi::c_void;
 
     /// Borrows a foreign-owned object.
@@ -89,6 +93,32 @@ unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {
     }
 }
 
+impl<T: 'static> ForeignOwnable for Pin<Box<T>> {
+    type Borrowed<'a> = Pin<&'a T>;
+
+    fn into_foreign(self) -> *const core::ffi::c_void {
+        // SAFETY: We are still treating the box as pinned.
+        Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }) as _
+    }
+
+    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Pin<&'a T> {
+        // SAFETY: The safety requirements for this function ensure that the object is still alive,
+        // so it is safe to dereference the raw pointer.
+        // The safety requirements of `from_foreign` also ensure that the object remains alive for
+        // the lifetime of the returned value.
+        let r = unsafe { &*ptr.cast() };
+
+        // SAFETY: This pointer originates from a `Pin<Box<T>>`.
+        unsafe { Pin::new_unchecked(r) }
+    }
+
+    unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {
+        // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
+        // call to `Self::into_foreign`.
+        unsafe { Pin::new_unchecked(Box::from_raw(ptr as _)) }
+    }
+}
+
 impl ForeignOwnable for () {
     type Borrowed<'a> = ();
 
@@ -366,6 +396,35 @@ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
             _p: PhantomData,
         }
     }
+
+    /// Consumes the `ARef`, returning a raw pointer.
+    ///
+    /// This function does not change the refcount. After calling this function, the caller is
+    /// responsible for the refcount previously managed by the `ARef`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use core::ptr::NonNull;
+    /// use kernel::types::{ARef, AlwaysRefCounted};
+    ///
+    /// struct Empty {}
+    ///
+    /// unsafe impl AlwaysRefCounted for Empty {
+    ///     fn inc_ref(&self) {}
+    ///     unsafe fn dec_ref(_obj: NonNull<Self>) {}
+    /// }
+    ///
+    /// let mut data = Empty {};
+    /// let ptr = NonNull::<Empty>::new(&mut data as *mut _).unwrap();
+    /// let data_ref: ARef<Empty> = unsafe { ARef::from_raw(ptr) };
+    /// let raw_ptr: NonNull<Empty> = ARef::into_raw(data_ref);
+    ///
+    /// assert_eq!(ptr, raw_ptr);
+    /// ```
+    pub fn into_raw(me: Self) -> NonNull<T> {
+        ManuallyDrop::new(me).ptr
+    }
 }
 
 impl<T: AlwaysRefCounted> Clone for ARef<T> {

rust/macros/lib.rs

@@ -2,6 +2,10 @@
 
 //! Crate for all kernel procedural macros.
 
+// When fixdep scans this, it will find this string `CONFIG_RUSTC_VERSION_TEXT`
+// and thus add a dependency on `include/config/RUSTC_VERSION_TEXT`, which is
+// touched by Kconfig when the version string from the compiler changes.
+
 #[macro_use]
 mod quote;
 mod concat_idents;

rust/macros/module.rs

@@ -260,6 +260,12 @@ mod __module_init {{
                         unsafe {{ __init() }}
                     }}
 
+                    #[cfg(MODULE)]
+                    #[doc(hidden)]
+                    #[used]
+                    #[link_section = \".init.data\"]
+                    static __UNIQUE_ID___addressable_init_module: unsafe extern \"C\" fn() -> i32 = init_module;
+
                     #[cfg(MODULE)]
                     #[doc(hidden)]
                     #[no_mangle]
@@ -273,6 +279,12 @@ mod __module_init {{
                         unsafe {{ __exit() }}
                     }}
 
+                    #[cfg(MODULE)]
+                    #[doc(hidden)]
+                    #[used]
+                    #[link_section = \".exit.data\"]
+                    static __UNIQUE_ID___addressable_cleanup_module: extern \"C\" fn() = cleanup_module;
+
                     // Built-in modules are initialized through an initcall pointer
                     // and the identifiers need to be unique.
                     #[cfg(not(MODULE))]

scripts/Kconfig.include

@@ -64,3 +64,11 @@ ld-version := $(shell,set -- $(ld-info) && echo $2)
 cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))
 m32-flag := $(cc-option-bit,-m32)
 m64-flag := $(cc-option-bit,-m64)
+
+# $(rustc-option,<flag>)
+# Return y if the Rust compiler supports <flag>, n otherwise
+# Calls to this should be guarded so that they are not evaluated if
+# CONFIG_RUST_IS_AVAILABLE is not set.
+# If you are testing for unstable features, consider testing RUSTC_VERSION
+# instead, as features may have different completeness while available.
+rustc-option = $(success,trap "rm -rf .tmp_$$" EXIT; mkdir .tmp_$$; $(RUSTC) $(1) --crate-type=rlib /dev/null --out-dir=.tmp_$$ -o .tmp_$$/tmp.rlib)

scripts/Makefile.build

@@ -273,10 +273,15 @@ rust_common_cmd = \
 # would not match each other.
 
 quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
-      cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $<
+      cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool)
+
+define rule_rustc_o_rs
+	$(call cmd_and_fixdep,rustc_o_rs)
+	$(call cmd,gen_objtooldep)
+endef
 
 $(obj)/%.o: $(obj)/%.rs FORCE
-	+$(call if_changed_dep,rustc_o_rs)
+	+$(call if_changed_rule,rustc_o_rs)
 
 quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_rsi_rs = \

scripts/Makefile.compiler

@@ -72,3 +72,18 @@ clang-min-version = $(call test-ge, $(CONFIG_CLANG_VERSION), $1)
 # ld-option
 # Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
 ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
+
+# __rustc-option
+# Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage)
+__rustc-option = $(call try-run,\
+	$(1) $(2) $(3) --crate-type=rlib /dev/null --out-dir=$$TMPOUT -o "$$TMP",$(3),$(4))
+
+# rustc-option
+# Usage: rustflags-y += $(call rustc-option,-Cinstrument-coverage,-Zinstrument-coverage)
+rustc-option = $(call __rustc-option, $(RUSTC),\
+	$(KBUILD_RUSTFLAGS),$(1),$(2))
+
+# rustc-option-yn
+# Usage: flag := $(call rustc-option-yn,-Cinstrument-coverage)
+rustc-option-yn = $(call try-run,\
+	$(RUSTC) $(KBUILD_RUSTFLAGS) $(1) --crate-type=rlib /dev/null --out-dir=$$TMPOUT -o "$$TMP",y,n)

scripts/Makefile.kasan

@@ -12,6 +12,11 @@ endif
 KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
 
 cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
+rustc-param = $(call rustc-option, -Cllvm-args=-$(1),)
+
+check-args = $(foreach arg,$(2),$(call $(1),$(arg)))
+
+kasan_params :=
 
 ifdef CONFIG_KASAN_STACK
 	stack_enable := 1
@@ -41,39 +46,59 @@ CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
 		$(call cc-option, -fsanitize=kernel-address \
 		-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
 
-# Now, add other parameters enabled similarly in both GCC and Clang.
-# As some of them are not supported by older compilers, use cc-param.
-CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
-		$(call cc-param,asan-stack=$(stack_enable)) \
-		$(call cc-param,asan-instrument-allocas=1) \
-		$(call cc-param,asan-globals=1)
+# The minimum supported `rustc` version has a minimum supported LLVM
+# version late enough that we can assume support for -asan-mapping-offset.
+RUSTFLAGS_KASAN := -Zsanitizer=kernel-address \
+		   -Zsanitizer-recover=kernel-address \
+		   -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET)
+
+# Now, add other parameters enabled similarly in GCC, Clang, and rustc.
+# As some of them are not supported by older compilers, these will be filtered
+# through `cc-param` or `rust-param` as applicable.
+kasan_params += asan-instrumentation-with-call-threshold=$(call_threshold) \
+		asan-stack=$(stack_enable) \
+		asan-instrument-allocas=1 \
+		asan-globals=1
 
 # Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
 # instead. With compilers that don't support this option, compiler-inserted
 # memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures.
-CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
+kasan_params += asan-kernel-mem-intrinsic-prefix=1
 
 endif # CONFIG_KASAN_GENERIC
 
 ifdef CONFIG_KASAN_SW_TAGS
 
+CFLAGS_KASAN := -fsanitize=kernel-hwaddress
+
+# This sets flags that will enable SW_TAGS KASAN once enabled in Rust. These
+# will not work today, and is guarded against in dependencies for CONFIG_RUST.
+RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \
+		   -Zsanitizer-recover=kernel-hwaddress
+
 ifdef CONFIG_KASAN_INLINE
-	instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
+	kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
 else
-	instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
+	kasan_params += hwasan-instrument-with-calls=1
 endif
 
-CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
-		$(call cc-param,hwasan-instrument-stack=$(stack_enable)) \
-		$(call cc-param,hwasan-use-short-granules=0) \
-		$(call cc-param,hwasan-inline-all-checks=0) \
-		$(instrumentation_flags)
+kasan_params += hwasan-instrument-stack=$(stack_enable) \
+		hwasan-use-short-granules=0 \
+		hwasan-inline-all-checks=0
 
 # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
 ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
-	CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
+	kasan_params += hwasan-kernel-mem-intrinsic-prefix=1
 endif
 
 endif # CONFIG_KASAN_SW_TAGS
 
-export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
+# Add all as-supported KASAN LLVM parameters requested by the configuration.
+CFLAGS_KASAN += $(call check-args, cc-param, $(kasan_params))
+
+ifdef CONFIG_RUST
+	# Avoid calling `rustc-param` unless Rust is enabled.
+	RUSTFLAGS_KASAN += $(call check-args, rustc-param, $(kasan_params))
+endif # CONFIG_RUST
+
+export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN

scripts/Makefile.lib

@@ -146,6 +146,9 @@ ifneq ($(CONFIG_KASAN_HW_TAGS),y)
 _c_flags += $(if $(patsubst n%,, \
 		$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
 		$(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
+_rust_flags += $(if $(patsubst n%,, \
+		$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
+		$(RUSTFLAGS_KASAN))
 endif
 endif
 

scripts/generate_rust_target.rs

@@ -20,12 +20,28 @@ enum Value {
     Boolean(bool),
     Number(i32),
     String(String),
+    Array(Vec<Value>),
     Object(Object),
 }
 
 type Object = Vec<(String, Value)>;
 
-/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
+fn comma_sep<T>(
+    seq: &[T],
+    formatter: &mut Formatter<'_>,
+    f: impl Fn(&mut Formatter<'_>, &T) -> Result,
+) -> Result {
+    if let [ref rest @ .., ref last] = seq[..] {
+        for v in rest {
+            f(formatter, v)?;
+            formatter.write_str(",")?;
+        }
+        f(formatter, last)?;
+    }
+    Ok(())
+}
+
+/// Minimal "almost JSON" generator (e.g. no `null`s, no escaping),
 /// enough for this purpose.
 impl Display for Value {
     fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
@@ -33,59 +49,67 @@ fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
             Value::Boolean(boolean) => write!(formatter, "{}", boolean),
             Value::Number(number) => write!(formatter, "{}", number),
             Value::String(string) => write!(formatter, "\"{}\"", string),
+            Value::Array(values) => {
+                formatter.write_str("[")?;
+                comma_sep(&values[..], formatter, |formatter, v| v.fmt(formatter))?;
+                formatter.write_str("]")
+            }
             Value::Object(object) => {
                 formatter.write_str("{")?;
-                if let [ref rest @ .., ref last] = object[..] {
-                    for (key, value) in rest {
-                        write!(formatter, "\"{}\": {},", key, value)?;
-                    }
-                    write!(formatter, "\"{}\": {}", last.0, last.1)?;
-                }
+                comma_sep(&object[..], formatter, |formatter, v| {
+                    write!(formatter, "\"{}\": {}", v.0, v.1)
+                })?;
                 formatter.write_str("}")
             }
         }
     }
 }
 
-struct TargetSpec(Object);
-
-impl TargetSpec {
-    fn new() -> TargetSpec {
-        TargetSpec(Vec::new())
+impl From<bool> for Value {
+    fn from(value: bool) -> Self {
+        Self::Boolean(value)
     }
 }
 
-trait Push<T> {
-    fn push(&mut self, key: &str, value: T);
+impl From<i32> for Value {
+    fn from(value: i32) -> Self {
+        Self::Number(value)
+    }
 }
 
-impl Push<bool> for TargetSpec {
-    fn push(&mut self, key: &str, value: bool) {
-        self.0.push((key.to_string(), Value::Boolean(value)));
+impl From<String> for Value {
+    fn from(value: String) -> Self {
+        Self::String(value)
     }
 }
 
-impl Push<i32> for TargetSpec {
-    fn push(&mut self, key: &str, value: i32) {
-        self.0.push((key.to_string(), Value::Number(value)));
+impl From<&str> for Value {
+    fn from(value: &str) -> Self {
+        Self::String(value.to_string())
     }
 }
 
-impl Push<String> for TargetSpec {
-    fn push(&mut self, key: &str, value: String) {
-        self.0.push((key.to_string(), Value::String(value)));
+impl From<Object> for Value {
+    fn from(object: Object) -> Self {
+        Self::Object(object)
     }
 }
 
-impl Push<&str> for TargetSpec {
-    fn push(&mut self, key: &str, value: &str) {
-        self.push(key, value.to_string());
+impl<T: Into<Value>, const N: usize> From<[T; N]> for Value {
+    fn from(i: [T; N]) -> Self {
+        Self::Array(i.into_iter().map(|v| v.into()).collect())
     }
 }
 
-impl Push<Object> for TargetSpec {
-    fn push(&mut self, key: &str, value: Object) {
-        self.0.push((key.to_string(), Value::Object(value)));
+struct TargetSpec(Object);
+
+impl TargetSpec {
+    fn new() -> TargetSpec {
+        TargetSpec(Vec::new())
+    }
+
+    fn push(&mut self, key: &str, value: impl Into<Value>) {
+        self.0.push((key.to_string(), value.into()));
     }
 }
 
@@ -164,10 +188,26 @@ fn main() {
         );
         let mut features = "-mmx,+soft-float".to_string();
         if cfg.has("MITIGATION_RETPOLINE") {
+            // The kernel uses `-mretpoline-external-thunk` (for Clang), which Clang maps to the
+            // target feature of the same name plus the other two target features in
+            // `clang/lib/Driver/ToolChains/Arch/X86.cpp`. These should be eventually enabled via
+            // `-Ctarget-feature` when `rustc` starts recognizing them (or via a new dedicated
+            // flag); see https://github.com/rust-lang/rust/issues/116852.
             features += ",+retpoline-external-thunk";
+            features += ",+retpoline-indirect-branches";
+            features += ",+retpoline-indirect-calls";
+        }
+        if cfg.has("MITIGATION_SLS") {
+            // The kernel uses `-mharden-sls=all`, which Clang maps to both these target features in
+            // `clang/lib/Driver/ToolChains/Arch/X86.cpp`. These should be eventually enabled via
+            // `-Ctarget-feature` when `rustc` starts recognizing them (or via a new dedicated
+            // flag); see https://github.com/rust-lang/rust/issues/116851.
+            features += ",+harden-sls-ijmp";
+            features += ",+harden-sls-ret";
         }
         ts.push("features", features);
         ts.push("llvm-target", "x86_64-linux-gnu");
+        ts.push("supported-sanitizers", ["kcfi", "kernel-address"]);
         ts.push("target-pointer-width", "64");
     } else if cfg.has("X86_32") {
         // This only works on UML, as i386 otherwise needs regparm support in rustc

scripts/rustc-version.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Usage: $ ./rustc-version.sh rustc
+#
+# Print the Rust compiler version in a 6 or 7-digit form.
+
+# Convert the version string x.y.z to a canonical up-to-7-digits form.
+#
+# Note that this function uses one more digit (compared to other
+# instances in other version scripts) to give a bit more space to
+# `rustc` since it will reach 1.100.0 in late 2026.
+get_canonical_version()
+{
+	IFS=.
+	set -- $1
+	echo $((100000 * $1 + 100 * $2 + $3))
+}
+
+if output=$("$@" --version 2>/dev/null); then
+	set -- $output
+	get_canonical_version $2
+else
+	echo 0
+	exit 1
+fi

tools/objtool/check.c

@@ -177,6 +177,52 @@ static bool is_sibling_call(struct instruction *insn)
 	return (is_static_jump(insn) && insn_call_dest(insn));
 }
 
+/*
+ * Checks if a string ends with another.
+ */
+static bool str_ends_with(const char *s, const char *sub)
+{
+	const int slen = strlen(s);
+	const int sublen = strlen(sub);
+
+	if (sublen > slen)
+		return 0;
+
+	return !memcmp(s + slen - sublen, sub, sublen);
+}
+
+/*
+ * Checks if a function is a Rust "noreturn" one.
+ */
+static bool is_rust_noreturn(const struct symbol *func)
+{
+	/*
+	 * If it does not start with "_R", then it is not a Rust symbol.
+	 */
+	if (strncmp(func->name, "_R", 2))
+		return false;
+
+	/*
+	 * These are just heuristics -- we do not control the precise symbol
+	 * name, due to the crate disambiguators (which depend on the compiler)
+	 * as well as changes to the source code itself between versions (since
+	 * these come from the Rust standard library).
+	 */
+	return str_ends_with(func->name, "_4core5sliceSp15copy_from_slice17len_mismatch_fail")		||
+	       str_ends_with(func->name, "_4core6option13unwrap_failed")				||
+	       str_ends_with(func->name, "_4core6result13unwrap_failed")				||
+	       str_ends_with(func->name, "_4core9panicking5panic")					||
+	       str_ends_with(func->name, "_4core9panicking9panic_fmt")					||
+	       str_ends_with(func->name, "_4core9panicking14panic_explicit")				||
+	       str_ends_with(func->name, "_4core9panicking14panic_nounwind")				||
+	       str_ends_with(func->name, "_4core9panicking18panic_bounds_check")			||
+	       str_ends_with(func->name, "_4core9panicking19assert_failed_inner")			||
+	       str_ends_with(func->name, "_4core9panicking36panic_misaligned_pointer_dereference")	||
+	       strstr(func->name, "_4core9panicking11panic_const24panic_const_")			||
+	       (strstr(func->name, "_4core5slice5index24slice_") &&
+		str_ends_with(func->name, "_fail"));
+}
+
 /*
  * This checks to see if the given function is a "noreturn" function.
  *
@@ -202,10 +248,14 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 	if (!func)
 		return false;
 
-	if (func->bind == STB_GLOBAL || func->bind == STB_WEAK)
+	if (func->bind == STB_GLOBAL || func->bind == STB_WEAK) {
+		if (is_rust_noreturn(func))
+			return true;
+
 		for (i = 0; i < ARRAY_SIZE(global_noreturns); i++)
 			if (!strcmp(func->name, global_noreturns[i]))
 				return true;
+	}
 
 	if (func->bind == STB_WEAK)
 		return false;

tools/objtool/noreturns.h

@@ -39,6 +39,8 @@ NORETURN(panic)
 NORETURN(panic_smp_self_stop)
 NORETURN(rest_init)
 NORETURN(rewind_stack_and_make_dead)
+NORETURN(rust_begin_unwind)
+NORETURN(rust_helper_BUG)
 NORETURN(sev_es_terminate)
 NORETURN(snp_abort)
 NORETURN(start_kernel)