From e90f97ce20575cd0cdbe01db588f907448b6d9f2 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Tue, 3 Feb 2026 11:34:08 +0000 Subject: kbuild: rust: add `CONFIG_RUSTC_CLANG_LLVM_COMPATIBLE` This config detects if Rust and Clang have matching LLVM major version. All IR or bitcode operations (e.g. LTO) rely on LLVM major version to be matching, otherwise it may generate errors, or worse, miscompile silently due to change of IR semantics. It's usually suggested to use the exact same LLVM version, but this can be difficult to guarantee. Rust's suggestion [1] is also major-version only, so I think this check is sufficient for the kernel. Link: https://doc.rust-lang.org/rustc/linker-plugin-lto.html [1] Reviewed-by: Andreas Hindborg Signed-off-by: Gary Guo Signed-off-by: Matthew Maurer Signed-off-by: Alice Ryhl Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Reviewed-by: Nicolas Schier Tested-by: Nicolas Schier Tested-by: Andreas Hindborg Link: https://patch.msgid.link/20260203-inline-helpers-v2-1-beb8547a03c9@google.com [ Fixed typo. - Miguel ] Signed-off-by: Miguel Ojeda --- init/Kconfig | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 444ce811ea67..36d32ea44594 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -82,6 +82,21 @@ config RUSTC_LLVM_VERSION int default $(rustc-llvm-version) +config RUSTC_LLVM_MAJOR_VERSION + int + default $(shell,expr $(rustc-llvm-version) / 10000) + +config RUSTC_CLANG_LLVM_COMPATIBLE + bool + default y if CC_IS_CLANG && RUSTC_LLVM_MAJOR_VERSION = $(shell,expr $(cc-version) / 10000) + help + This indicates whether Rust and Clang use LLVM of the same major + version. + + Operations involving handling LLVM IR or bitcode (e.g. cross-language + LTO) require the same LLVM major version to work properly. For best + compatibility it is recommended that the exact same LLVM is used. + config ARCH_HAS_CC_CAN_LINK bool -- cgit From b28711ac98e8b43bfbf5c918022018a54dcedd45 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 6 Apr 2026 01:52:44 +0200 Subject: rust: simplify `RUSTC_VERSION` Kconfig conditions With the Rust version bump in place, several Kconfig conditions based on `RUSTC_VERSION` are always true. Thus simplify them. The minimum supported major LLVM version by our new Rust minimum version is now LLVM 18, instead of LLVM 16. However, there are no possible cleanups for `RUSTC_LLVM_VERSION`. Reviewed-by: Tamir Duberstein Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260405235309.418950-9-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- arch/Kconfig | 3 +-- arch/arm64/Kconfig | 8 -------- arch/riscv/Kconfig | 3 --- init/Kconfig | 2 -- 4 files changed, 1 insertion(+), 15 deletions(-) (limited to 'init') diff --git a/arch/Kconfig b/arch/Kconfig index 102ddbd4298e..84089e80584b 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -968,10 +968,9 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC def_bool y depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS - depends on RUSTC_VERSION >= 107900 depends on ARM64 || X86_64 # With GCOV/KASAN we need this fix: https://github.com/rust-lang/rust/pull/129373 - depends on (RUSTC_LLVM_VERSION >= 190103 && RUSTC_VERSION >= 108200) || \ + depends on RUSTC_LLVM_VERSION >= 190103 || \ (!GCOV_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS) config CFI_PERMISSIVE diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 38dba5f7e4d2..c91130c7fba1 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -291,14 +291,6 @@ config ARM64 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 diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 90c531e6abf5..ddc534402400 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -232,9 +232,6 @@ config RISCV 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 diff --git a/init/Kconfig b/init/Kconfig index 36d32ea44594..b8a1ab0d49d4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2193,9 +2193,7 @@ config RUST depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC select CFI_ICALL_NORMALIZE_INTEGERS if CFI - depends on !CALL_PADDING || RUSTC_VERSION >= 108100 depends on !KASAN_SW_TAGS - depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 help Enables Rust support in the kernel. -- cgit From 9b398d0565438e9929afbfbb8a1cd1f3242067ac Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 6 Apr 2026 01:52:45 +0200 Subject: rust: remove `RUSTC_HAS_SLICE_AS_FLATTENED` and simplify code With the Rust version bump in place, the `RUSTC_HAS_SLICE_AS_FLATTENED` Kconfig (automatic) option is always true. Thus remove the option and simplify the code. In particular, this includes removing the `slice` module which contained the temporary slice helpers, i.e. the `AsFlattened` extension trait and its `impl`s. Reviewed-by: Tamir Duberstein Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260405235309.418950-10-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- init/Kconfig | 3 --- rust/kernel/lib.rs | 1 - rust/kernel/prelude.rs | 3 --- rust/kernel/slice.rs | 49 ------------------------------------------------- 4 files changed, 56 deletions(-) delete mode 100644 rust/kernel/slice.rs (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index b8a1ab0d49d4..c38f49228157 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -178,9 +178,6 @@ config LD_CAN_USE_KEEP_IN_OVERLAY # https://github.com/llvm/llvm-project/pull/130661 def_bool LD_IS_BFD || LLD_VERSION >= 210000 -config RUSTC_HAS_SLICE_AS_FLATTENED - def_bool RUSTC_VERSION >= 108000 - config RUSTC_HAS_COERCE_POINTEE def_bool RUSTC_VERSION >= 108400 diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 138d846f798d..621cae75030c 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -140,7 +140,6 @@ pub mod scatterlist; pub mod security; pub mod seq_file; pub mod sizes; -pub mod slice; #[cfg(CONFIG_SOC_BUS)] pub mod soc; #[doc(hidden)] diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index e9d37f307f2a..44edf72a4a24 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -107,6 +107,3 @@ pub use super::{ // `super::std_vendor` is hidden, which makes the macro inline for some reason. #[doc(no_inline)] pub use super::dbg; - -#[cfg(not(CONFIG_RUSTC_HAS_SLICE_AS_FLATTENED))] -pub use super::slice::AsFlattened; diff --git a/rust/kernel/slice.rs b/rust/kernel/slice.rs deleted file mode 100644 index ca2cde135061..000000000000 --- a/rust/kernel/slice.rs +++ /dev/null @@ -1,49 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 - -//! Additional (and temporary) slice helpers. - -/// Extension trait providing a portable version of [`as_flattened`] and -/// [`as_flattened_mut`]. -/// -/// In Rust 1.80, the previously unstable `slice::flatten` family of methods -/// have been stabilized and renamed from `flatten` to `as_flattened`. -/// -/// This creates an issue for as long as the MSRV is < 1.80, as the same functionality is provided -/// by different methods depending on the compiler version. -/// -/// This extension trait solves this by abstracting `as_flatten` and calling the correct method -/// depending on the Rust version. -/// -/// This trait can be removed once the MSRV passes 1.80. -/// -/// [`as_flattened`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_flattened -/// [`as_flattened_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_flattened_mut -#[cfg(not(CONFIG_RUSTC_HAS_SLICE_AS_FLATTENED))] -pub trait AsFlattened { - /// Takes a `&[[T; N]]` and flattens it to a `&[T]`. - /// - /// This is an portable layer on top of [`as_flattened`]; see its documentation for details. - /// - /// [`as_flattened`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_flattened - fn as_flattened(&self) -> &[T]; - - /// Takes a `&mut [[T; N]]` and flattens it to a `&mut [T]`. - /// - /// This is an portable layer on top of [`as_flattened_mut`]; see its documentation for details. - /// - /// [`as_flattened_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_flattened_mut - fn as_flattened_mut(&mut self) -> &mut [T]; -} - -#[cfg(not(CONFIG_RUSTC_HAS_SLICE_AS_FLATTENED))] -impl AsFlattened for [[T; N]] { - #[allow(clippy::incompatible_msrv)] - fn as_flattened(&self) -> &[T] { - self.flatten() - } - - #[allow(clippy::incompatible_msrv)] - fn as_flattened_mut(&mut self) -> &mut [T] { - self.flatten_mut() - } -} -- cgit From 4ab22c543f18cfbcc2f8ae691dc5ec5cc0ac35fb Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 6 Apr 2026 01:52:46 +0200 Subject: rust: remove `RUSTC_HAS_COERCE_POINTEE` and simplify code With the Rust version bump in place, the `RUSTC_HAS_COERCE_POINTEE` Kconfig (automatic) option is always true. Thus remove the option and simplify the code. In particular, this includes removing our use of the predecessor unstable features we used with Rust < 1.84.0 (`coerce_unsized`, `dispatch_from_dyn` and `unsize`). Reviewed-by: Tamir Duberstein Acked-by: Danilo Krummrich Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260405235309.418950-11-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- init/Kconfig | 3 --- rust/kernel/alloc/kbox.rs | 29 ++--------------------------- rust/kernel/lib.rs | 8 +------- rust/kernel/list/arc.rs | 22 +--------------------- rust/kernel/sync/arc.rs | 21 ++------------------- 5 files changed, 6 insertions(+), 77 deletions(-) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index c38f49228157..f9fac458e4d4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -178,9 +178,6 @@ config LD_CAN_USE_KEEP_IN_OVERLAY # https://github.com/llvm/llvm-project/pull/130661 def_bool LD_IS_BFD || LLD_VERSION >= 210000 -config RUSTC_HAS_COERCE_POINTEE - def_bool RUSTC_VERSION >= 108400 - config RUSTC_HAS_SPAN_FILE def_bool RUSTC_VERSION >= 108800 diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index 622b3529edfc..bd6da02c7ab8 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -77,33 +77,8 @@ use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption}; /// `self.0` is always properly aligned and either points to memory allocated with `A` or, for /// zero-sized types, is a dangling, well aligned pointer. #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] -pub struct Box<#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, pointee)] T: ?Sized, A: Allocator>( - NonNull, - PhantomData, -); - -// This is to allow coercion from `Box` to `Box` if `T` can be converted to the -// dynamically-sized type (DST) `U`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::CoerceUnsized> for Box -where - T: ?Sized + core::marker::Unsize, - U: ?Sized, - A: Allocator, -{ -} - -// This is to allow `Box` to be dispatched on when `Box` can be coerced into `Box`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::DispatchFromDyn> for Box -where - T: ?Sized + core::marker::Unsize, - U: ?Sized, - A: Allocator, -{ -} +#[derive(core::marker::CoercePointee)] +pub struct Box<#[pointee] T: ?Sized, A: Allocator>(NonNull, PhantomData); /// Type alias for [`Box`] with a [`Kmalloc`] allocator. /// diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 621cae75030c..66a09d77a2c4 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -39,17 +39,11 @@ // // Expected to become stable. #![feature(arbitrary_self_types)] +#![feature(derive_coerce_pointee)] // // To be determined. #![feature(used_with_arg)] // -// `feature(derive_coerce_pointee)` is expected to become stable. Before Rust -// 1.84.0, it did not exist, so enable the predecessor features. -#![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] -#![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] -#![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] -#![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))] -// // `feature(file_with_nul)` is expected to become stable. Before Rust 1.89.0, it did not exist, so // enable it conditionally. #![cfg_attr(CONFIG_RUSTC_HAS_FILE_WITH_NUL, feature(file_with_nul))] diff --git a/rust/kernel/list/arc.rs b/rust/kernel/list/arc.rs index e1082423909c..a9a2b0178f65 100644 --- a/rust/kernel/list/arc.rs +++ b/rust/kernel/list/arc.rs @@ -160,7 +160,7 @@ pub use impl_list_arc_safe; /// /// [`List`]: crate::list::List #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] +#[derive(core::marker::CoercePointee)] pub struct ListArc where T: ListArcSafe + ?Sized, @@ -443,26 +443,6 @@ where } } -// This is to allow coercion from `ListArc` to `ListArc` if `T` can be converted to the -// dynamically-sized type (DST) `U`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::CoerceUnsized> for ListArc -where - T: ListArcSafe + core::marker::Unsize + ?Sized, - U: ListArcSafe + ?Sized, -{ -} - -// This is to allow `ListArc` to be dispatched on when `ListArc` can be coerced into -// `ListArc`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::DispatchFromDyn> for ListArc -where - T: ListArcSafe + core::marker::Unsize + ?Sized, - U: ListArcSafe + ?Sized, -{ -} - /// A utility for tracking whether a [`ListArc`] exists using an atomic. /// /// # Invariants diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index 921e19333b89..18d6c0d62ce0 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -128,7 +128,7 @@ mod std_vendor; /// # Ok::<(), Error>(()) /// ``` #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] +#[derive(core::marker::CoercePointee)] pub struct Arc { ptr: NonNull>, // NB: this informs dropck that objects of type `ArcInner` may be used in ` as @@ -182,15 +182,6 @@ impl ArcInner { } } -// This is to allow coercion from `Arc` to `Arc` if `T` can be converted to the -// dynamically-sized type (DST) `U`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl, U: ?Sized> core::ops::CoerceUnsized> for Arc {} - -// This is to allow `Arc` to be dispatched on when `Arc` can be coerced into `Arc`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl, U: ?Sized> core::ops::DispatchFromDyn> for Arc {} - // SAFETY: It is safe to send `Arc` to another thread when the underlying `T` is `Sync` because // it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs // `T` to be `Send` because any thread that has an `Arc` may ultimately access `T` using a @@ -547,20 +538,12 @@ impl From>> for Arc { /// # Ok::<(), Error>(()) /// ``` #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] +#[derive(core::marker::CoercePointee)] pub struct ArcBorrow<'a, T: ?Sized + 'a> { inner: NonNull>, _p: PhantomData<&'a ()>, } -// This is to allow `ArcBorrow` to be dispatched on when `ArcBorrow` can be coerced into -// `ArcBorrow`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl, U: ?Sized> core::ops::DispatchFromDyn> - for ArcBorrow<'_, T> -{ -} - impl Clone for ArcBorrow<'_, T> { fn clone(&self) -> Self { *self -- cgit From 93553d9922b07555344095b5d9202a3f5b84541c Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 6 Apr 2026 01:52:57 +0200 Subject: rust: kbuild: remove "dummy parameter" workaround for `bindgen` < 0.71.1 Until the version bump of `bindgen`, we needed to pass a dummy parameter to avoid failing the `--version` call. Thus remove it. Reviewed-by: Tamir Duberstein Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260405235309.418950-22-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- init/Kconfig | 7 +------ scripts/rust_is_available.sh | 8 +------- 2 files changed, 2 insertions(+), 13 deletions(-) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index f9fac458e4d4..d9b795f70a38 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2211,12 +2211,7 @@ config RUSTC_VERSION_TEXT config BINDGEN_VERSION_TEXT string depends on RUST - # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 - # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 - # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed - # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 - # both fixed the issue). - default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" + default "$(shell,$(BINDGEN) --version 2>/dev/null)" # # Place an empty function call at each tracepoint site. Can be diff --git a/scripts/rust_is_available.sh b/scripts/rust_is_available.sh index cefc456c2503..551f1ebd0dcb 100755 --- a/scripts/rust_is_available.sh +++ b/scripts/rust_is_available.sh @@ -121,14 +121,8 @@ fi # Check that the Rust bindings generator is suitable. # # Non-stable and distributions' versions may have a version suffix, e.g. `-dev`. -# -# The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 -# (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 -# (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed when -# the minimum version is upgraded past the latter (0.69.1 and 0.71.1 both fixed -# the issue). rust_bindings_generator_output=$( \ - LC_ALL=C "$BINDGEN" --version workaround-for-0.69.0 2>/dev/null + LC_ALL=C "$BINDGEN" --version 2>/dev/null ) || rust_bindings_generator_code=$? if [ -n "$rust_bindings_generator_code" ]; then echo >&2 "***" -- cgit