linux/rust/kernel/init.rs, branch v6.16

rust: init: Fix generics in *_init! macros

2025-06-29T16:30:45Z

The match pattern for a optional trailing comma in the list of generics is erroneously repeated in the code block resulting in following error: | error: attempted to repeat an expression containing no syntax variables matched as repeating at this depth | --> rust/kernel/init.rs:301:73 | | | 301 | ::pin_init::try_pin_init!($(&$this in)? $t $(::<$($generics),* $(,)?>)? { | | ^^^ Remove "$(,)?" from all code blocks in the try_init! and try_pin_init! definitions. Cc: stable@vger.kernel.org Fixes: 578eb8b6db13 ("rust: pin-init: move the default error behavior of `try_[pin_]init`") Signed-off-by: Janne Grunau Reviewed-by: Benno Lossin Link: https://lore.kernel.org/r/20250628-rust_init_trailing_comma-v1-1-2d162ae1a757@jannau.net 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: make pin-init its own crate

2025-03-16T20:59:19Z

Rename relative paths inside of the crate to still refer to the same items, also rename paths inside of the kernel crate and adjust the build system to build the crate. [ Remove the `expect` (and thus the `lint_reasons` feature) since the tree now uses `quote!` from `rust/macros/export.rs`. Remove the `TokenStream` import removal, since it is now used as well. In addition, temporarily (i.e. just for this commit) use an `--extern force:alloc` to prevent an unknown `new_uninit` error in the `rustdoc` target. For context, please see a similar case in: https://lore.kernel.org/lkml/20240422090644.525520-1-ojeda@kernel.org/ And adjusted the message above. - Miguel ] Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-16-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: pin-init: move `InPlaceInit` and impls of `InPlaceWrite` into the kernel crate

2025-03-16T20:59:18Z

In order to make pin-init a standalone crate, move kernel-specific code directly into the kernel crate. This includes the `InPlaceInit` trait, its implementations and the implementations of `InPlaceWrite` for `Arc` and `UniqueArc`. All of these use the kernel's error type which will become unavailable in pin-init. Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-9-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: pin-init: move the default error behavior of `try_[pin_]init`

2025-03-16T20:59:18Z

Move the ability to just write `try_pin_init!(Foo { a <- a_init })` (note the missing `? Error` at the end) into the kernel crate. Remove this notation from the pin-init crate, since the default when no error is specified is the kernel-internal `Error` type. Instead add two macros in the kernel crate that serve this default and are used instead of the ones from `pin-init`. This is done, because the `Error` type that is used as the default is from the kernel crate and it thus prevents making the pin-init crate standalone. In order to not cause a build error due to a name overlap, the macros in the pin-init crate are renamed, but this change is reverted in a future commit when it is a standalone crate. Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Reviewed-by: Andreas Hindborg Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-8-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: add extensions to the pin-init crate and move relevant documentation there

2025-03-16T20:59:18Z

In preparation of splitting off the pin-init crate from the kernel crate, move all kernel-specific documentation from pin-init back into the kernel crate. Also include an example from the user-space version [1] adapted to the kernel. The new `init.rs` file will also be populated by kernel-specific extensions to the pin-init crate by the next commits. Link: https://github.com/Rust-for-Linux/pin-init/blob/c1417c64c71229f0fd444d75e88f33e3c547c829/src/lib.rs#L161 [1] Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-4-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: move pin-init API into its own directory

2025-03-16T20:59:18Z

In preparation of splitting off the pin-init crate from the kernel crate, move all pin-init API code (including proc-macros) into `rust/pin-init`. Moved modules have their import path adjusted via the `#[path = "..."]` attribute. This allows the files to still be imported in the kernel crate even though the files are in different directories. Code that is moved out of files (but the file itself stays where it is) is imported via the `include!` macro. This also allows the code to be moved while still being part of the kernel crate. Note that this commit moves the generics parsing code out of the GPL-2.0 file `rust/macros/helpers.rs` into the Apache-2.0 OR MIT file `rust/pin_init/internal/src/helpers.rs`. I am the sole author of that code and it already is available with that license at [1]. The same is true for the entry-points of the proc-macros `pin_data`, `pinned_drop` and `derive_zeroable` in `rust/macros/lib.rs` that are moved to `rust/pin_data/internal/src/lib.rs`. Although there are some smaller patches that fix the doctests. Link: https://github.com/Rust-for-Linux/pinned-init [1] Signed-off-by: Benno Lossin Reviewed-by: Andreas Hindborg Reviewed-by: Fiona Behrens Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-3-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: init: disable doctests

2025-03-16T20:59:18Z

The build system cannot handle doctests in the kernel crate in files outside of `rust/kernel/`. Subsequent commits will move files out of that directory, but will still compile them as part of the kernel crate. Thus ignore all doctests in the to-be-moved files. Leave tests disabled until they are separated into their own crate and they stop causing breakage. Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Reviewed-by: Andreas Hindborg Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-2-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: init: add missing newline to pr_info! calls

2025-03-06T19:42:52Z

Several pr_info! calls in rust/kernel/init.rs (both in code examples and macro documentation) were missing a newline, causing logs to run together. This commit updates these calls to include a trailing newline, improving readability and consistency with the C side. Fixes: 6841d45a3030 ("rust: init: add `stack_pin_init!` macro") Fixes: 7f8977a7fe6d ("rust: init: add `{pin_}chain` functions to `{Pin}Init`") Fixes: d0fdc3961270 ("rust: init: add `PinnedDrop` trait and macros") Fixes: 4af84c6a85c6 ("rust: init: update expanded macro explanation") Reported-by: Miguel Ojeda Link: https://github.com/Rust-for-Linux/linux/issues/1139 Signed-off-by: Alban Kurti Link: https://lore.kernel.org/r/20250206-printing_fix-v3-3-a85273b501ae@invicto.ai [ Replaced Closes with Link since it fixes part of the issue. Added one more Fixes tag (still same set of stable kernels). - Miguel ] Signed-off-by: Miguel Ojeda

rust: init: fix `Zeroable` implementation for `Option>` and `Option>`

2025-03-05T22:57:39Z

According to [1], `NonNull` and `#[repr(transparent)]` wrapper types such as our custom `KBox` have the null pointer optimization only if `T: Sized`. Thus remove the `Zeroable` implementation for the unsized case. Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1] Reported-by: Alice Ryhl Closes: https://lore.kernel.org/rust-for-linux/CAH5fLghL+qzrD8KiCF1V3vf2YcC6aWySzkmaE2Zzrnh1gKj-hw@mail.gmail.com/ Cc: stable@vger.kernel.org # v6.12+ (a custom patch will be needed for 6.6.y) Fixes: 38cde0bd7b67 ("rust: init: add `Zeroable` trait and `init::zeroed` function") Signed-off-by: Benno Lossin Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250305132836.2145476-1-benno.lossin@proton.me [ Added Closes tag and moved up the Reported-by one. - Miguel ] Signed-off-by: Miguel Ojeda