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2026-03-30rust: rework `build_assert!` documentationGary Guo
Add a detailed comparison and recommendation of the three types of build-time assertion macro as module documentation (and un-hide the module to render them). The documentation on the macro themselves are simplified to only cover the scenarios where they should be used; links to the module documentation is added instead. Reviewed-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Danilo Krummrich <dakr@kernel.org> Link: https://patch.msgid.link/20260319121653.2975748-4-gary@kernel.org [ Added periods on comments. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-30rust: add `const_assert!` macroGary Guo
The macro is a more powerful version of `static_assert!` for use inside function contexts. This is powered by inline consts, so enable the feature for old compiler versions that does not have it stably. While it is possible already to write `const { assert!(...) }`, this provides a short hand that is more uniform with other assertions. It also formats nicer with rustfmt where it will not be formatted into multiple lines. Two users that would route via the Rust tree are converted. Reviewed-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Danilo Krummrich <dakr@kernel.org> Link: https://patch.msgid.link/20260319121653.2975748-3-gary@kernel.org [ Rebased. Fixed period typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-28rust: move `static_assert` into `build_assert`Gary Guo
Conceptually, `static_assert` is also a build-time assertion that occurs earlier in the pipeline. Consolidate the implementation so that we can use this as the canonical place to add more useful build-time assertions. Reviewed-by: Yury Norov <ynorov@nvidia.com> Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Danilo Krummrich <dakr@kernel.org> Link: https://patch.msgid.link/20260319121653.2975748-2-gary@kernel.org [ Used kernel vertical style. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-28rust: dma: add from-slice constructors for Coherent and CoherentBoxAlexandre Courbot
A very common pattern is to create a block of coherent memory with the content of an already-existing slice of bytes (e.g. a loaded firmware blob). `CoherentBox` makes this easier, but still implies a potentially panicking operation with `copy_from_slice` that requires a `PANIC` comment. Add `from_slice_with_attrs` and `from_slice` methods to both `Coherent` and `CoherentBox` to turn this into a trivial one-step operation. Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Danilo Krummrich <dakr@kernel.org> Link: https://patch.msgid.link/20260327-b4-nova-dma-removal-v2-1-616e1d0b5cb3@nvidia.com Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
2026-03-28rust: dma: add CoherentHandle for DMA allocations without kernel mappingDanilo Krummrich
Add CoherentHandle, an opaque DMA allocation type for buffers that are only ever accessed by hardware. Unlike Coherent<T>, it does not provide CPU access to the allocated memory. CoherentHandle implicitly sets DMA_ATTR_NO_KERNEL_MAPPING and stores the value returned by dma_alloc_attrs() as an opaque handle (NonNull<c_void>) rather than a typed pointer, since with this flag the C API returns an opaque cookie (e.g. struct page *), not a CPU pointer to the allocated memory. Only the DMA bus address is exposed to drivers; the opaque handle is used solely to free the allocation on drop. This commit is for reference only; there is currently no in-tree user. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260321172749.592387-2-dakr@kernel.org [acourbot: fix conflict in dma.rs.] Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
2026-03-28rust: dma: remove DMA_ATTR_NO_KERNEL_MAPPING from public attrsDanilo Krummrich
When DMA_ATTR_NO_KERNEL_MAPPING is passed to dma_alloc_attrs(), the returned CPU address is not a pointer to the allocated memory but an opaque handle (e.g. struct page *). Coherent<T> (or CoherentAllocation<T> respectively) stores this value as NonNull<T> and exposes methods that dereference it and even modify its contents. Remove the flag from the public attrs module such that drivers cannot pass it to Coherent<T> (or CoherentAllocation<T> respectively) in the first place. Instead DMA_ATTR_NO_KERNEL_MAPPING can be supported with an additional opaque type (e.g. CoherentHandle) which does not provide access to the allocated memory. Cc: stable@vger.kernel.org Fixes: ad2907b4e308 ("rust: add dma coherent allocator abstraction") Signed-off-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260321172749.592387-1-dakr@kernel.org Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
2026-03-27rust: dma: generalize BinaryWriter impl for Coherent<T>Danilo Krummrich
Generalize the BinaryWriter implementation from Coherent<[u8]> to Coherent<T> where T: KnownSize + AsBytes + ?Sized. The implementation only uses size() and write_dma(), neither of which depends on the inner type being a byte slice. This allows any Coherent allocation with an AsBytes inner type to be exposed as a debugfs binary file. Acked-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260325003921.3420-2-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-27rust: uaccess: generalize write_dma() to accept any Coherent<T>Danilo Krummrich
Generalize write_dma() from &Coherent<[u8]> to &Coherent<T> where T: KnownSize + AsBytes + ?Sized. The function body only uses as_ptr() and size(), which work for any such T, so there is no reason to restrict it to byte slices. Acked-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260325003921.3420-1-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-27rust: drm: gem: shmem: Add DRM shmem helper abstractionAsahi Lina
The DRM shmem helper includes common code useful for drivers which allocate GEM objects as anonymous shmem. Add a Rust abstraction for this. Drivers can choose the raw GEM implementation or the shmem layer, depending on their needs. Signed-off-by: Asahi Lina <lina@asahilina.net> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Janne Grunau <j@jananu.net> Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com> Link: https://patch.msgid.link/20260316211646.650074-6-lyude@redhat.com [ * DRM_GEM_SHMEM_HELPER is a tristate; when a module driver selects it, it becomes =m. The Rust kernel crate and its C helpers are always built into vmlinux and can't reference symbols from a module, causing link errors. Thus, add RUST_DRM_GEM_SHMEM_HELPER bool Kconfig that selects DRM_GEM_SHMEM_HELPER, forcing it built-in when Rust drivers need it; use cfg(CONFIG_RUST_DRM_GEM_SHMEM_HELPER) for the shmem module. * Add cfg_attr(not(CONFIG_RUST_DRM_GEM_SHMEM_HELPER), expect(unused)) on pub(crate) use impl_aref_for_gem_obj and BaseObjectPrivate, so that unused warnings are suppressed when shmem is not enabled. * Enable const_refs_to_static (stabilized in 1.83) to prevent build errors with older compilers. * Use &raw const for bindings::drm_gem_shmem_vm_ops and add #[allow(unused_unsafe, reason = "Safe since Rust 1.82.0")]. * Fix incorrect C Header path and minor spelling and formatting issues. * Drop shmem::Object::sg_table() as the current implementation is unsound. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-27rust: drm: gem: Add raw_dma_resv() functionLyude Paul
For retrieving a pointer to the struct dma_resv for a given GEM object. We also introduce it in a new trait, BaseObjectPrivate, which we automatically implement for all gem objects and don't expose to users outside of the crate. Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Janne Grunau <j@jananu.net> Tested-by: Janne Grunau <j@jannau.net> Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com> Link: https://patch.msgid.link/20260316211646.650074-3-lyude@redhat.com [ Fix incorrect reference in safety comment. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-27rust: helpers: Add bindings/wrappers for dma_resv_lockAsahi Lina
This is just for basic usage in the DRM shmem abstractions for implied locking, not intended as a full DMA Reservation abstraction yet. Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Christian König <christian.koenig@amd.com> Signed-off-by: Asahi Lina <lina+kernel@asahilina.net> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Janne Grunau <j@jannau.net> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Acked-by: David Airlie <airlied@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260320-gpuvm-rust-v5-2-76fd44f17a87@google.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-27rust: kernel: mark as `#[inline]` all `From::from()`s for `Error`Alistair Francis
There was a recent request [1] to mark as `#[inline]` the simple `From::from()` functions implemented for `Error`. Thus mark all of the existing impl From<...> for Error { fn from(err: ...) -> Self { ... } } functions in the `kernel` crate as `#[inline]`. Suggested-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/all/8403c8b7a832b5274743816eb77abfa4@garyguo.net/ [1] Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Andreas Hindborg <a.hindborg@kernel.org> Link: https://patch.msgid.link/20260326020406.1438210-1-alistair.francis@wdc.com [ Dropped `projection.rs` since it is in another tree and already marked as `inline(always)` and reworded accordingly. Changed Link tag to Gary's original message and added Suggested-by. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-27rust: list: hide macros from top-level kernel docGary Guo
Due to Rust macro scoping rules, all macros defined in a crate using `#[macro_export]` end up in the top-level. For the list macros, we re-export them inside the list module, and expect users to use `kernel::list::macro_name!()`. Use `#[doc(hidden)]` on the macro definition, and use `#[doc(inline)]` on the re-export to make the macro appear to be defined at module-level inside documentation. The other exported types are already automatically `#[doc(inline)]` because they are defined in a non-public module, so there is no need to split the macro re-exports out. Signed-off-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260312174700.4016015-1-gary@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-26rust: drm: use new sync::aref path for importsAlice Ryhl
ARef and AlwaysRefCounted are being moved to sync::aref, and the re-exports under types are planned to be removed. Thus, update imports to the new path. Acked-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260326-drm-rust-next-fix-aref-v1-2-7f6f58d2828a@google.com Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2026-03-26rust: workqueue: use new sync::aref path for importsAlice Ryhl
ARef and AlwaysRefCounted are being moved to sync::aref, and the re-exports under types are planned to be removed. Thus, update imports to the new path. Acked-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260326-drm-rust-next-fix-aref-v1-1-7f6f58d2828a@google.com Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2026-03-26rust: drm: dispatch delayed work items to the private dataDaniel Almeida
Much like the patch that dispatched (regular) work items, we also need to dispatch delayed work items in order not to trigger the orphan rule. This allows a drm::Device<T> to dispatch the delayed work to T::Data. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Link: https://lore.kernel.org/r/20260323-aref-workitem-v3-4-f59729b812aa@collabora.com Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2026-03-26rust: workqueue: add delayed work support for ARef<T>Daniel Almeida
The preceding patches added support for ARef<T> work items. By the same token, add support for delayed work items too. The rationale is the same: it may be convenient or even necessary at times to implement HasDelayedWork directly on ARef<T>. A follow up patch will also implement support for drm::Device as the first user. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Link: https://lore.kernel.org/r/20260323-aref-workitem-v3-3-f59729b812aa@collabora.com Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2026-03-26rust: drm: dispatch work items to the private dataDaniel Almeida
This implementation dispatches any work enqueued on ARef<drm::Device<T>> to its driver-provided handler. It does so by building upon the newly-added ARef<T> support in workqueue.rs in order to call into the driver implementations for work_container_of and raw_get_work. This is notably important for work items that need access to the drm device, as it was not possible to enqueue work on a ARef<drm::Device<T>> previously without failing the orphan rule. The current implementation needs T::Data to live inline with drm::Device in order for work_container_of to function. This restriction is already captured by the trait bounds. Drivers that need to share their ownership of T::Data may trivially get around this: // Lives inline in drm::Device struct DataWrapper { work: ..., // Heap-allocated, shared ownership. data: Arc<DriverData>, } Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Link: https://lore.kernel.org/r/20260323-aref-workitem-v3-2-f59729b812aa@collabora.com Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2026-03-26rust: workqueue: add support for ARef<T>Daniel Almeida
Add support for the ARef<T> smart pointer. This allows an instance of ARef<T> to handle deferred work directly, which can be convenient or even necessary at times, depending on the specifics of the driver or subsystem. The implementation is similar to that of Arc<T>, and a subsequent patch will implement support for drm::Device as the first user. This is notably important for work items that need access to the drm device, as it was not possible to enqueue work on a ARef<drm::Device<T>> previously without failing the orphan rule. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Link: https://lore.kernel.org/r/20260323-aref-workitem-v3-1-f59729b812aa@collabora.com Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2026-03-26rust: gem: Introduce DriverObject::ArgsLyude Paul
This is an associated type that may be used in order to specify a data-type to pass to gem objects when constructing them, allowing for drivers to more easily initialize their private-data for gem objects. Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Janne Grunau <j@jananu.net> Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com> Link: https://patch.msgid.link/20260316211646.650074-5-lyude@redhat.com [ Resolve merge conflicts in Tyr. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-26rust: drm: Add gem::impl_aref_for_gem_obj!Lyude Paul
In the future we're going to be introducing more GEM object types in rust then just gem::Object<T>. Since all types of GEM objects have refcounting, let's introduce a macro that we can use in the gem crate in order to copy this boilerplate implementation for each type: impl_aref_for_gem_obj!(). Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Janne Grunau <j@jananu.net> Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com> Link: https://patch.msgid.link/20260316211646.650074-2-lyude@redhat.com [ Resolve merge conflicts. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-25rust: pin-init: replace `addr_of_mut!` with `&raw mut`Antonio Hickey
`feature(raw_ref_op)` became stable in Rust 1.82.0 which is the current MSRV of pin-init with no default features. Earlier Rust versions will now need to enable `raw_ref_op` to continue to work with pin-init. This reduces visual complexity and improves consistency with existing reference syntax. Suggested-by: Benno Lossin <lossin@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1148 Closes: https://github.com/Rust-for-Linux/pin-init/issues/99 Signed-off-by: Antonio Hickey <contact@antoniohickey.com> Link: https://github.com/Rust-for-Linux/pin-init/commit/e27763004e2f6616b089437fbe9b3719cd72bd5c [ Reworded commit message. - Benno ] Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260319093542.3756606-6-lossin@kernel.org Signed-off-by: Benno Lossin <lossin@kernel.org>
2026-03-25rust: pin-init: implement ZeroableOption for NonZero* integer typesHamdan-Khan
Add a macro for implementing `ZeroableOption` for `NonZero*` types. `Option<NonZero*>` now automatically implements `Zeroable` trait by implementing `ZeroableOption` for `NonZero*` types, which serves as a blanket impl. Closes: https://github.com/Rust-for-Linux/pin-init/issues/95 Signed-off-by: Hamdan-Khan <hamdankhan212@gmail.com> Link: https://github.com/Rust-for-Linux/pin-init/commit/74f772641cd9670848fa360f4ebfd20fdb40bf78 [ Fixed a typo in the commit message. - Benno ] Link: https://patch.msgid.link/20260319093542.3756606-5-lossin@kernel.org Signed-off-by: Benno Lossin <lossin@kernel.org>
2026-03-25rust: pin-init: doc: de-clutter documentation with fake-variadicsGary Guo
Currently the doc for `Zeroable` and `ZeroableOption` are filled with the generated impl of tuples and fn pointers. Use the internal "fake_variadics" feature to improve the rendered quality. This makes use of an internal feature, however this is of minimal risk as it's for documentation only, not activated during normal build, gated behind `USE_RUSTC_FEATURES`, and can be removed at any time. This feature is already used by serde and bevy to improve documentation quality. For compilers that cannot use this feature, we still hide most generated impls, and the existence of them are hinted by doc comments on the single non-hidden impl. Signed-off-by: Gary Guo <gary@garyguo.net> Link: https://github.com/Rust-for-Linux/pin-init/commit/530c4eb79a449599e219821f9397f03250cc2aa4 [ Reordered `#[doc]` attributes and safety comments to avoid errors in older versions of clippy. - Benno ] Link: https://patch.msgid.link/20260319093542.3756606-4-lossin@kernel.org Signed-off-by: Benno Lossin <lossin@kernel.org>
2026-03-25rust: pin-init: properly document let binding workaroundBenno Lossin
The three let bindings (in the bodies of `cast_init`, `cast_pin_init` and the `init!` macro) are used to avoid the following compiler error in Rust 1.78.0, 1.79.0, 1.80.0, 1.80.1, and 1.81.0 (just showing the one for `cast_init`, the others are similar): error[E0391]: cycle detected when computing type of opaque `cast_init::{opaque#0}` --> src/lib.rs:1160:66 | 1160 | pub const unsafe fn cast_init<T, U, E>(init: impl Init<T, E>) -> impl Init<U, E> { | ^^^^^^^^^^^^^^^ | note: ...which requires borrow-checking `cast_init`... --> src/lib.rs:1160:1 | 1160 | pub const unsafe fn cast_init<T, U, E>(init: impl Init<T, E>) -> impl Init<U, E> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires const checking `cast_init`... --> src/lib.rs:1160:1 | 1160 | pub const unsafe fn cast_init<T, U, E>(init: impl Init<T, E>) -> impl Init<U, E> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: ...which requires computing whether `cast_init::{opaque#0}` is freeze... = note: ...which requires evaluating trait selection obligation `cast_init::{opaque#0}: core::marker::Freeze`... = note: ...which again requires computing type of opaque `cast_init::{opaque#0}`, completing the cycle note: cycle used when computing type of `cast_init::{opaque#0}` --> src/lib.rs:1160:66 | 1160 | pub const unsafe fn cast_init<T, U, E>(init: impl Init<T, E>) -> impl Init<U, E> { | ^^^^^^^^^^^^^^^ = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information Once we raise the nightly-MSRV above 1.81, we can remove this workaround. Link: https://github.com/Rust-for-Linux/pin-init/commit/bb3e96f3e9a4f5fca80a22af883c7e5aa90f0893 [ Moved this commit after the previous one to avoid a build failure due to unstable features. Changed the cfg to use `USE_RUSTC_FEAUTURES`. - Benno ] Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260319093542.3756606-3-lossin@kernel.org Signed-off-by: Benno Lossin <lossin@kernel.org>
2026-03-25rust: pin-init: build: simplify use of nightly featuresGary Guo
We use some features that are already stable in later versions of Rust, but only available as unstable features in older Rust versions that the kernel needs to support. Instead of checking if a feature is already stable, simply enable them and allow the warning if the feature is already stable. This avoids the need of hardcoding whether a feature has been stabilized at a given version. `#[feature(...)]` is used when cfg `USE_RUSTC_FEATURES` is enabled. The build script automatically does this when a nightly compiler is detected or `RUSTC_BOOTSTRAP` is set. Signed-off-by: Gary Guo <gary@garyguo.net> Link: https://github.com/Rust-for-Linux/pin-init/commit/885c5d83d7eb778a796d4a17380a0898b0d0a571 [ Added kernel build system changes to always enable USE_RUSTC_FEATURES. Moved this commit earlier (swapped with the next one) to avoid a build error. - Benno ] Link: https://patch.msgid.link/20260319093542.3756606-2-lossin@kernel.org Signed-off-by: Benno Lossin <lossin@kernel.org>
2026-03-25rust: dma: implement BinaryWriter for Coherent<[u8]>Timur Tabi
Implement the BinaryWriter trait for Coherent<[u8]>, enabling DMA coherent allocations to be exposed as readable binary files. The implementation handles offset tracking and bounds checking, copying data from the coherent allocation to userspace via write_dma(). Signed-off-by: Timur Tabi <ttabi@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Tested-by: John Hubbard <jhubbard@nvidia.com> Tested-by: Eliot Courtney <ecourtney@nvidia.com> Link: https://patch.msgid.link/20260319212658.2541610-4-ttabi@nvidia.com [ Rebase onto Coherent<T> changes. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-25rust: uaccess: add write_dma() for copying from DMA buffers to userspaceTimur Tabi
Add UserSliceWriter::write_dma() to copy data from a Coherent<[u8]> to userspace. This provides a safe interface for copying DMA buffer contents to userspace without requiring callers to work with raw pointers. Because write_dma() and write_slice() have common code, factor that code out into a helper function, write_raw(). The method handles bounds checking and offset calculation internally, wrapping the unsafe copy_to_user() call. Signed-off-by: Timur Tabi <ttabi@nvidia.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: John Hubbard <jhubbard@nvidia.com> Tested-by: Eliot Courtney <ecourtney@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260319212658.2541610-3-ttabi@nvidia.com [ Rebase onto Coherent<T> changes; remove unnecessary turbofish from cast(). - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-24rust: device: add device name methodTimur Tabi
Add a name() method to the `Device` type, which returns a CStr that contains the device name. Signed-off-by: Timur Tabi <ttabi@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Gary Guo <gary@garyguo.net> Tested-by: John Hubbard <jhubbard@nvidia.com> Tested-by: Eliot Courtney <ecourtney@nvidia.com> Link: https://patch.msgid.link/20260319212658.2541610-2-ttabi@nvidia.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-24rust: regulator: do not assume that regulator_get() returns non-nullAlice Ryhl
The Rust `Regulator` abstraction uses `NonNull` to wrap the underlying `struct regulator` pointer. When `CONFIG_REGULATOR` is disabled, the C stub for `regulator_get` returns `NULL`. `from_err_ptr` does not treat `NULL` as an error, so it was passed to `NonNull::new_unchecked`, causing undefined behavior. Fix this by using a raw pointer `*mut bindings::regulator` instead of `NonNull`. This allows `inner` to be `NULL` when `CONFIG_REGULATOR` is disabled, and leverages the C stubs which are designed to handle `NULL` or are no-ops. Fixes: 9b614ceada7c ("rust: regulator: add a bare minimum regulator abstraction") Reported-by: Miguel Ojeda <ojeda@kernel.org> Closes: https://lore.kernel.org/r/20260322193830.89324-1-ojeda@kernel.org Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Link: https://patch.msgid.link/20260324-regulator-fix-v1-1-a5244afa3c15@google.com Signed-off-by: Mark Brown <broonie@kernel.org>
2026-03-23rust: dma: remove dma::CoherentAllocation<T>Danilo Krummrich
Now that everything has been converted to the new dma::Coherent<T> API, remove dma::CoherentAllocation<T>. Suggested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/DH8O47F2GM1Z.3H3E13RSKIV22@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: dma: add Coherent:init() and Coherent::init_with_attrs()Danilo Krummrich
Analogous to Coherent::zeroed() and Coherent::zeroed_with_attrs(), add Coherent:init() and Coherent::init_with_attrs() which both take an impl Init<T, E> argument initializing the DMA coherent memory. Compared to CoherentInit, Coherent::init() is a one-shot constructor that runs an Init closure and immediately exposes the DMA handle, whereas CoherentInit is a multi-stage initializer that provides safe &mut T access by withholding the DMA address until converted to Coherent. Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260320194626.36263-6-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: dma: introduce dma::CoherentBox for memory initializationDanilo Krummrich
Currently, dma::Coherent cannot safely provide (mutable) access to its underlying memory because the memory might be concurrently accessed by a DMA device. This makes it difficult to safely initialize the memory before handing it over to the hardware. Introduce dma::CoherentBox, a type that encapsulates a dma::Coherent before its DMA address is exposed to the device. dma::CoherentBox can guarantee exclusive access to the inner dma::Coherent and implement Deref and DerefMut. Once the memory is properly initialized, dma::CoherentBox can be converted into a regular dma::Coherent. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260320194626.36263-5-dakr@kernel.org [ Remove unnecessary trait bounds. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: dma: add zeroed constructor to `Coherent`Gary Guo
These constructors create a coherent container of a single object instead of slice. They are named `zeroed` and `zeroed_with_attrs` to emphasis that they are created initialized zeroed. It is intended that there'll be new constructors that take `PinInit` instead of zeroing. Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260320194626.36263-4-dakr@kernel.org [ Use kernel import style. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: dma: add generalized container for types other than slicesGary Guo
Currently, `CoherentAllocation` is concecptually a DMA coherent container of a slice of `[T]` of runtime-checked length. Generalize it by creating `dma::Coherent<T>` which can hold any value of `T`. `Coherent::alloc_with_attrs` is implemented but not yet exposed, as I believe we should not expose the way to obtain an uninitialized coherent region. `Coherent<[T]>` provides a `len` method instead of the previous `count()` method to be consistent with methods on slices. The existing type is re-defined as a type alias of `Coherent<[T]>` to ease transition. Methods in use are not yet removed. Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260320194626.36263-3-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: dma: use "kernel vertical" style for importsDanilo Krummrich
Convert all imports to use "kernel vertical" style. With this, subsequent patches neither introduce unrelated changes nor leave an inconsistent import pattern. While at it, drop unnecessary imports covered by prelude::*. Link: https://docs.kernel.org/rust/coding-guidelines.html#imports Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260320194626.36263-2-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: gpu: Add GPU buddy allocator bindingsJoel Fernandes
Add safe Rust abstractions over the Linux kernel's GPU buddy allocator for physical memory management. The GPU buddy allocator implements a binary buddy system useful for GPU physical memory allocation. nova-core will use it for physical memory allocation. Cc: Nikola Djukic <ndjukic@nvidia.com> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260320045711.43494-2-joelagnelf@nvidia.com [ * Use doc-comments for GpuBuddyAllocMode methods and GpuBuddyGuard, * Fix comma splice in GpuBuddyParams::chunk_size doc-comment, * Remove redundant summary in GpuBuddy::new doc-comment, * Drop Rust helper for gpu_buddy_block_size(). - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23rust: interop: Add list module for C linked list interfaceJoel Fernandes
Add a new module `kernel::interop::list` for working with C's doubly circular linked lists. Provide low-level iteration over list nodes. Typed iteration over actual items is provided with a `clist_create` macro to assist in creation of the `CList` type. Cc: Nikola Djukic <ndjukic@nvidia.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Gary Guo <gary@garyguo.net> Acked-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com> Link: https://patch.msgid.link/20260319210722.1543776-1-joelagnelf@nvidia.com [ * Remove stray empty comment and double blank line in doctest, * Improve wording and fix a few typos, * Use markdown emphasis instead of caps, * Move interop/mod.rs to interop.rs. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-23hrtimer: add usage examples to documentationAndreas Hindborg
Add documentation examples showing various ways to use hrtimers: - Box-allocated timers with shared state in Arc. - Arc-allocated timers. - Stack-based timers for scoped usage. - Mutable stack-based timers with shared state. Tested-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://msgid.link/20260219-hrtimer-examples-v6-19-rc1-v2-1-810cc06ca9f6@kernel.org Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2026-03-23rust: time: make ClockSource unsafe traitFUJITA Tomonori
Mark the ClockSource trait as unsafe and document its safety requirements. Specifically, implementers must guarantee that their `ktime_get()` implementation returns a value in the inclusive range [0, KTIME_MAX]. Update all existing implementations to use `unsafe impl` with corresponding safety comments. Note that there could be potential users of a customized clock source [1] so we don't seal the trait. Link: https://lore.kernel.org/rust-for-linux/Z9xb1r1x5tOzAIZT@boqun-archlinux/ [1] Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://msgid.link/20250630131011.405219-1-fujita.tomonori@gmail.com [ Change range expressions in docs. - Andreas ] Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2026-03-23rust/time: Add Delta::from_nanos()Lyude Paul
Since rvkms is going to need to create its own Delta instances, and we already have functions for creating Delta with every other unit of time. Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://msgid.link/20251114184207.459335-1-lyude@redhat.com Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2026-03-23rust: str: improve safety comment for CString::try_from_fmtNakamura Shuta
Improve the safety comment for the `inc_len()` call in `CString::try_from_fmt()` to clarify why `bytes_written()` is guaranteed not to exceed the buffer capacity. The current comment states that bytes written is bounded by size, but does not explain that this invariant is maintained because: 1. The `Formatter` is created with `size` as its capacity limit 2. The `?` operators on `write_fmt` and `write_str` ensure early return if writing exceeds this limit Suggested-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/rust-for-linux/20221114145329.0f47a3ab@GaryWorkstation/ Link: https://github.com/Rust-for-Linux/linux/issues/936 Signed-off-by: Nakamura Shuta <nakamura.shuta@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260119062925.1647-1-nakamura.shuta@gmail.com [ Updated tags: it was a suggestion from Gary from the mailing list (the linked issue is mostly about adding a `debug_assert_eq!`). - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-18rust: devres: embed struct devres_node directlyDanilo Krummrich
Currently, the Devres<T> container uses devm_add_action() to register a devres callback. devm_add_action() allocates a struct action_devres, which on top of struct devres_node, just keeps a data pointer and release function pointer. This is an unnecessary indirection, given that analogous to struct devres, the Devres<T> container can just embed a struct devres_node directly without an additional allocation. In contrast to struct devres, we don't need to force an alignment of ARCH_DMA_MINALIGN (as struct devres does to account for the worst case) since we have generics in Rust. I.e. the compiler already ensures correct alignment of the embedded T in Devres<T>. Thus, get rid of devm_add_action() and instead embed a struct devres_node directly. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://patch.msgid.link/20260213220718.82835-6-dakr@kernel.org [ * Improve comment about core::any::type_name(), * add #[must_use] to devres_node_remove(), * use container_of!() in devres_node_free_node(). - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17Merge tag 'rust_io-7.1-rc1' of ↵Danilo Krummrich
git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core into drm-rust-next Register abstraction and I/O infrastructure improvements Introduce the register!() macro to define type-safe I/O register accesses. Refactor the IoCapable trait into a functional trait, which simplifies I/O backends and removes the need for overloaded Io methods. This is a stable tag for other trees to merge. Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17Merge tag 'rust_io-7.1-rc1' into driver-core-nextDanilo Krummrich
Register abstraction and I/O infrastructure improvements Introduce the register!() macro to define type-safe I/O register accesses. Refactor the IoCapable trait into a functional trait, which simplifies I/O backends and removes the need for overloaded Io methods. This is a stable tag for other trees to merge. Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17rust: io: introduce `write_reg` and `LocatedRegister`Alexandre Courbot
Some I/O types, like fixed address registers, carry their location alongside their values. For these types, the regular `Io::write` method can lead into repeating the location information twice: once to provide the location itself, another time to build the value. We are also considering supporting making all register values carry their full location information for convenience and safety. Add a new `Io::write_reg` method that takes a single argument implementing `LocatedRegister`, a trait that decomposes implementors into a `(location, value)` tuple. This allows write operations on fixed offset registers to be done while specifying their name only once. Suggested-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/all/DH0XBLXZD81K.22SWIZ1ZAOW1@kernel.org/ Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260314-register-v9-8-86805b2f7e9d@nvidia.com [ Replace FIFO with VERSION register in the examples. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17rust: io: add `register!` macroAlexandre Courbot
Add a macro for defining hardware register types with I/O accessors. Each register field is represented as a `Bounded` of the appropriate bit width, ensuring field values are never silently truncated. Fields can optionally be converted to/from custom types, either fallibly or infallibly. The address of registers can be direct, relative, or indexed, supporting most of the patterns in which registers are arranged. Suggested-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/all/20250306222336.23482-6-dakr@kernel.org/ Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260314-register-v9-7-86805b2f7e9d@nvidia.com [ * Improve wording and formatting of doc-comments, * Import build_assert!(), * Add missing inline annotations, * Call static_assert!() with absolute path, * Use expect instead of allow. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17rust: io: use generic read/write accessors for primitive accessesAlexandre Courbot
By providing the required `IoLoc` implementations on `usize`, we can leverage the generic accessors and reduce the number of unsafe blocks in the module. This also allows us to directly call the generic `read/write/update` methods with primitive types, so add examples illustrating this. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260314-register-v9-6-86805b2f7e9d@nvidia.com [ Slightly improve wording in doc-comment. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17rust: io: add IoLoc type and generic I/O accessorsAlexandre Courbot
I/O accesses are defined by the following properties: - An I/O location, which consists of a start address, a width, and a type to interpret the read value as, - A value, which is returned for reads or provided for writes. Introduce the `IoLoc` trait, which allows implementing types to fully specify an I/O location. This allows I/O operations to be made generic through the new `read` and `write` methods. This design will allow us to factorize the I/O code working with primitives, and to introduce ways to perform I/O with a higher degree of control through register types. Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260314-register-v9-5-86805b2f7e9d@nvidia.com [ Fix incorrect reference to io_addr_assert() in try_update(). - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-03-17rust: num: make Bounded::get constAlexandre Courbot
There is a need to access the inner value of a `Bounded` in const context, notably for bitfields and registers. Remove the invariant check of `Bounded::get`, which allows us to make it const. Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Link: https://patch.msgid.link/20260314-register-v9-4-86805b2f7e9d@nvidia.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>