linux/rust/bindings, branch v6.15

rust: clean Rust 1.88.0's `unnecessary_transmutes` lint

2025-05-06T22:11:47Z

Starting with Rust 1.88.0 (expected 2025-06-26) [1][2], `rustc` may introduce a new lint that catches unnecessary transmutes, e.g.: error: unnecessary transmute --> rust/uapi/uapi_generated.rs:23242:18 | 23242 | unsafe { ::core::mem::transmute(self._bitfield_1.get(0usize, 1u8) as u8) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this with: `(self._bitfield_1.get(0usize, 1u8) as u8 == 1)` | = note: `-D unnecessary-transmutes` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(unnecessary_transmutes)]` There are a lot of them (at least 300), but luckily they are all in `bindgen`-generated code. Thus clean all up by allowing it there. Since unknown lints trigger a lint itself in older compilers, do it conditionally so that we can keep the `unknown_lints` lint enabled. Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Link: https://github.com/rust-lang/rust/pull/136083 [1] Link: https://github.com/rust-lang/rust/issues/136067 [2] Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250502140237.1659624-4-ojeda@kernel.org Signed-off-by: Miguel Ojeda

Merge tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

2025-03-31T00:03:26Z

Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Extract the 'pin-init' API from the 'kernel' crate and make it into a standalone crate. In order to do this, the contents are rearranged so that they can easily be kept in sync with the version maintained out-of-tree that other projects have started to use too (or plan to, like QEMU). This will reduce the maintenance burden for Benno, who will now have his own sub-tree, and will simplify future expected changes like the move to use 'syn' to simplify the implementation. - Add '#[test]'-like support based on KUnit. We already had doctests support based on KUnit, which takes the examples in our Rust documentation and runs them under KUnit. Now, we are adding the beginning of the support for "normal" tests, similar to those the '#[test]' tests in userspace Rust. For instance: #[kunit_tests(my_suite)] mod tests { #[test] fn my_test() { assert_eq!(1 + 1, 2); } } Unlike with doctests, the 'assert*!'s do not map to the KUnit assertion APIs yet. - Check Rust signatures at compile time for functions called from C by name. In particular, introduce a new '#[export]' macro that can be placed in the Rust function definition. It will ensure that the function declaration on the C side matches the signature on the Rust function: #[export] pub unsafe extern "C" fn my_function(a: u8, b: i32) -> usize { // ... } The macro essentially forces the compiler to compare the types of the actual Rust function and the 'bindgen'-processed C signature. These cases are rare so far. In the future, we may consider introducing another tool, 'cbindgen', to generate C headers automatically. Even then, having these functions explicitly marked may be a good idea anyway. - Enable the 'raw_ref_op' Rust feature: it is already stable, and allows us to use the new '&raw' syntax, avoiding a couple macros. After everyone has migrated, we will disallow the macros. - Pass the correct target to 'bindgen' on Usermode Linux. - Fix 'rusttest' build in macOS. 'kernel' crate: - New 'hrtimer' module: add support for setting up intrusive timers without allocating when starting the timer. Add support for 'Pin>', 'Arc<_>', 'Pin<&_>' and 'Pin<&mut _>' as pointer types for use with timer callbacks. Add support for setting clock source and timer mode. - New 'dma' module: add a simple DMA coherent allocator abstraction and a test sample driver. - 'list' module: make the linked list 'Cursor' point between elements, rather than at an element, which is more convenient to us and allows for cursors to empty lists; and document it with examples of how to perform common operations with the provided methods. - 'str' module: implement a few traits for 'BStr' as well as the 'strip_prefix()' method. - 'sync' module: add 'Arc::as_ptr'. - 'alloc' module: add 'Box::into_pin'. - 'error' module: extend the 'Result' documentation, including a few examples on different ways of handling errors, a warning about using methods that may panic, and links to external documentation. 'macros' crate: - 'module' macro: add the 'authors' key to support multiple authors. The original key will be kept until everyone has migrated. Documentation: - Add error handling sections. MAINTAINERS: - Add Danilo Krummrich as reviewer of the Rust "subsystem". - Add 'RUST [PIN-INIT]' entry with Benno Lossin as maintainer. It has its own sub-tree. - Add sub-tree for 'RUST [ALLOC]'. - Add 'DMA MAPPING HELPERS DEVICE DRIVER API [RUST]' entry with Abdiel Janulgue as primary maintainer. It will go through the sub-tree of the 'RUST [ALLOC]' entry. - Add 'HIGH-RESOLUTION TIMERS [RUST]' entry with Andreas Hindborg as maintainer. It has its own sub-tree. And a few other cleanups and improvements" * tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (71 commits) rust: dma: add `Send` implementation for `CoherentAllocation` rust: macros: fix `make rusttest` build on macOS rust: block: refactor to use `&raw mut` rust: enable `raw_ref_op` feature rust: uaccess: name the correct function rust: rbtree: fix comments referring to Box instead of KBox rust: hrtimer: add maintainer entry rust: hrtimer: add clocksource selection through `ClockId` rust: hrtimer: add `HrTimerMode` rust: hrtimer: implement `HrTimerPointer` for `Pin>` rust: alloc: add `Box::into_pin` rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>` rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>` rust: hrtimer: add `hrtimer::ScopedHrTimerPointer` rust: hrtimer: add `UnsafeHrTimerPointer` rust: hrtimer: allow timer restart from timer handler rust: str: implement `strip_prefix` for `BStr` rust: str: implement `AsRef` for `[u8]` and `BStr` rust: str: implement `Index` for `BStr` rust: str: implement `PartialEq` for `BStr` ...

rust: add dma coherent allocator abstraction

2025-03-20T20:44:46Z

Add a simple dma coherent allocator rust abstraction. Based on Andreas Hindborg's dma abstractions from the rnvme driver, which was also based on earlier work by Wedson Almeida Filho. Reviewed-by: Alice Ryhl Signed-off-by: Abdiel Janulgue Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250317185345.2608976-3-abdiel.janulgue@gmail.com Nacked-by: Christoph Hellwig [ Removed period. - Miguel ] Signed-off-by: Miguel Ojeda

panic_qr: use new #[export] macro

2025-03-09T19:52:46Z

This validates at compile time that the signatures match what is in the header file. It highlights one annoyance with the compile-time check, which is that it can only be used with functions marked unsafe. If the function is not unsafe, then this error is emitted: error[E0308]: `if` and `else` have incompatible types --> /drivers/gpu/drm/drm_panic_qr.rs:987:19 | 986 | #[export] | --------- expected because of this 987 | pub extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize { | ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected unsafe fn, found safe fn | = note: expected fn item `unsafe extern "C" fn(_, _) -> _ {kernel::bindings::drm_panic_qr_max_data_size}` found fn item `extern "C" fn(_, _) -> _ {drm_panic_qr_max_data_size}` The signature declarations are moved to a header file so it can be included in the Rust bindings helper, and the extern keyword is removed as it is unnecessary. Reviewed-by: Andreas Hindborg Reviewed-by: Tamir Duberstein Acked-by: Simona Vetter Acked-by: Greg Kroah-Hartman Signed-off-by: Alice Ryhl Reviewed-by: Jocelyn Falempe Link: https://lore.kernel.org/r/20250303-export-macro-v3-5-41fbad85a27f@google.com [ Fixed `rustfmt`. Moved on top the unsafe requirement comment to follow the usual style, and slightly reworded it for clarity. Formatted bindings helper comment. - Miguel ] Signed-off-by: Miguel Ojeda

rust: Add cpumask helpers

2025-02-28T18:34:40Z

In order to prepare for adding Rust abstractions for cpumask, add the required helpers for inline cpumask functions that cannot be called by rust code directly. Reviewed-by: Alice Ryhl Signed-off-by: Viresh Kumar Signed-off-by: Yury Norov [NVIDIA]

rust/kernel: Add faux device bindings

2025-02-13T15:58:58Z

This introduces a module for working with faux devices in rust, along with adding sample code to show how the API is used. Unlike other types of devices, we don't provide any hooks for device probe/removal - since these are optional for the faux API and are unnecessary in rust. Signed-off-by: Lyude Paul Cc: Maíra Canal Cc: Danilo Krummrich Cc: Miguel Ojeda Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/2025021026-exert-accent-b4c6@gregkh Signed-off-by: Greg Kroah-Hartman

rust: device: Add property_present()

2025-01-15T17:22:34Z

This implements Device::property_present(), which calls C APIs device_property_present() helper. The new helper will be used by Rust based cpufreq drivers. Signed-off-by: Viresh Kumar Link: https://lore.kernel.org/r/f43fe3f7b3151a89c261ad728b0f3bb2fc24caef.1736766672.git.viresh.kumar@linaro.org Signed-off-by: Greg Kroah-Hartman

rust: platform: add basic platform device / driver abstractions

2024-12-20T16:21:05Z

Implement the basic platform bus abstractions required to write a basic platform driver. This includes the following data structures: The `platform::Driver` trait represents the interface to the driver and provides `platform::Driver::probe` for the driver to implement. The `platform::Device` abstraction represents a `struct platform_device`. In order to provide the platform bus specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `platform::Adapter`. Reviewed-by: Rob Herring (Arm) Signed-off-by: Danilo Krummrich Tested-by: Dirk Behme Link: https://lore.kernel.org/r/20241219170425.12036-15-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman

rust: driver: implement `Adapter`

2024-12-20T16:21:05Z

In order to not duplicate code in bus specific implementations (e.g. platform), implement a generic `driver::Adapter` to represent the connection of matched drivers and devices. Bus specific `Adapter` implementations can simply implement this trait to inherit generic functionality, such as matching OF or ACPI device IDs and ID table entries. Suggested-by: Rob Herring (Arm) Signed-off-by: Danilo Krummrich Tested-by: Dirk Behme Link: https://lore.kernel.org/r/20241219170425.12036-14-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman

rust: pci: add basic PCI device / driver abstractions

2024-12-20T16:19:26Z

Implement the basic PCI abstractions required to write a basic PCI driver. This includes the following data structures: The `pci::Driver` trait represents the interface to the driver and provides `pci::Driver::probe` for the driver to implement. The `pci::Device` abstraction represents a `struct pci_dev` and provides abstractions for common functions, such as `pci::Device::set_master`. In order to provide the PCI specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `pci::Adapter`. `pci::DeviceId` implements PCI device IDs based on the generic `device_id::RawDevceId` abstraction. Co-developed-by: FUJITA Tomonori Signed-off-by: FUJITA Tomonori Signed-off-by: Danilo Krummrich Tested-by: Dirk Behme Link: https://lore.kernel.org/r/20241219170425.12036-10-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman