Commit Graph

854 Commits

Author SHA1 Message Date
Albin Babu Varghese
b61b0092ea rust: list: replace unwrap() with ? in doctest examples
Using `unwrap()` in kernel doctests can cause panics on error and may
give newcomers the mistaken impression that panicking is acceptable
in kernel code.

Replace all `.unwrap()` calls in `kernel::list`
examples with `.ok_or(EINVAL)?` so that errors are properly propagated.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1164
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Albin Babu Varghese <albinbabuvarghese20@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250527204928.5117-1-albinbabuvarghese20@gmail.com
[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-24 01:01:12 +02:00
Jesung Yang
5d4ffc531a rust: kunit: use crate-level mapping for c_void
Remove `use core::ffi::c_void`, which shadows `kernel::ffi::c_void`
brought in via `use crate::prelude::*`, to maintain consistency and
centralize the abstraction.

Since `kernel::ffi::c_void` is a straightforward re-export of
`core::ffi::c_void`, both are functionally equivalent. However, using
`kernel::ffi::c_void` improves consistency across the kernel's Rust code
and provides a unified reference point in case the definition ever needs
to change, even if such a change is unlikely.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089/topic/x/near/520452733
Signed-off-by: Jesung Yang <y.j3ms.n@gmail.com>
Link: https://lore.kernel.org/r/20250528174953.2948570-1-y.j3ms.n@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-24 00:55:22 +02:00
Alexandre Courbot
06a93197e2 rust: sizes: add constants up to SZ_2G
nova-core will need to use SZ_1M, so make the remaining constants
available.

Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-5-ecf41ef99252@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 18:12:30 +02:00
Alexandre Courbot
69ba00fed9 rust: make ETIMEDOUT error available
We will use this error in the nova-core driver.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-4-ecf41ef99252@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 18:12:30 +02:00
Danilo Krummrich
a002488de6 Merge tag 'topic/dma-features-2025-06-23' of https://github.com/Rust-for-Linux/linux.git
DMA features for v6.17

- Clarify wording and be consistent in 'coherent' nomenclature.

- Convert the read!() / write!() macros to return a Result.

- Add as_slice() / write() methods in CoherentAllocation.

- Fix doc-comment of dma_handle().

- Expose count() and size() in CoherentAllocation and add the
  corresponding type invariants.

- Implement CoherentAllocation::dma_handle_with_offset().
2025-06-23 17:53:17 +02:00
Danilo Krummrich
c7e03c5cf0 Merge tag 'topic/dma-features-2025-06-23' into alloc-next
DMA features for v6.17

- Clarify wording and be consistent in 'coherent' nomenclature.

- Convert the read!() / write!() macros to return a Result.

- Add as_slice() / write() methods in CoherentAllocation.

- Fix doc-comment of dma_handle().

- Expose count() and size() in CoherentAllocation and add the
  corresponding type invariants.

- Implement CoherentAllocation::dma_handle_with_offset().
2025-06-23 17:38:52 +02:00
Alexandre Courbot
26af856539 rust: dma: add dma_handle_with_offset method to CoherentAllocation
Sometimes one may want to obtain a DMA handle starting at a given
offset. This can be done by adding said offset to the result of
`dma_handle()`, but doing so on the client side carries the risk that
the operation will go outside the bounds of the allocation.

Thus, add a `dma_handle_with_offset` method that adds the desired offset
after checking that it is still valid.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-3-ecf41ef99252@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 17:11:07 +02:00
Alexandre Courbot
c0a3065d5d rust: dma: expose the count and size of CoherentAllocation
These properties are very useful to have (and to be used by nova-core)
and should be accessible, hence add them.

Additionally, add type invariants for the size of an allocation.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-2-ecf41ef99252@nvidia.com
[ Slightly extend the commit message. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 17:11:07 +02:00
Alexandre Courbot
14371e58cb rust: dma: fix doc-comment of dma_handle()
A word was apparently missing in this sentence, hence fix it.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-1-ecf41ef99252@nvidia.com
Fixes: ad2907b4e3 ("rust: add dma coherent allocator abstraction")
[ Slightly expand commit subject and add 'Fixes:' tag. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 17:10:44 +02:00
Abdiel Janulgue
d37a39f607 rust: dma: add as_slice/write functions for CoherentAllocation
Add unsafe accessors for the region for reading or writing large
blocks of data.

Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250602085444.1925053-4-abdiel.janulgue@gmail.com
[ Fix line length and slightly reword safety comment in doc-test of
  CoherentAllocation::write(); fix formatting issue. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 15:44:30 +02:00
Abdiel Janulgue
fe58465905 rust: dma: convert the read/write macros to return Result
We could do better here by having the macros return `Result`,
so that we don't have to wrap these calls in a closure for
validation which is confusing.

Co-developed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/87h63qhz4q.fsf@kernel.org/
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Link: https://lore.kernel.org/r/20250602085444.1925053-3-abdiel.janulgue@gmail.com
[ Fix line length in dma_read!(). - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 15:34:13 +02:00
Abdiel Janulgue
9863f77433 rust: dma: clarify wording and be consistent in coherent nomenclature
In the kernel, `consistent` and `coherent` are used interchangeably for the
region described in this api. Stick with `coherent` nomenclature
to show that dma_alloc_coherent() is being used, in addition to improving
the clarity in the DMA mapping attributes documentation.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250602085444.1925053-2-abdiel.janulgue@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-23 15:25:18 +02:00
Greg Kroah-Hartman
63dafeb392 Merge 6.16-rc3 into driver-core-next
We need the driver-core fixes that are in 6.16-rc3 into here as well
to build on top of.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-23 07:53:36 +02:00
Abhinav Ananthu
22679d807d rust: opp: use c_* types via kernel prelude
Update OPP FFI callback signatures to use `c_int` from the `kernel::prelude`,
instead of accessing it via `kernel::ffi::c_int`.

Although these types are defined in a crate named `ffi`, they are re-exported
via the `kernel::prelude` and should be used from there. This aligns with the
Rust-for-Linux coding guidelines and ensures ABI correctness when interfacing
with C code.

Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2025-06-23 09:52:45 +05:30
Abhinav Ananthu
b0a86fb0b2 rust: cpufreq: use c_ types from kernel prelude
Update cpufreq FFI callback signatures to use `c_int` from the `kernel::prelude`,
rather than accessing it explicitly through `kernel::ffi::c_int`.

Although these types are defined in the `ffi` crate, they are re-exported
via `kernel::prelude`. This aligns with the Rust-for-Linux coding
guidelines and ensures proper C ABI compatibility across platforms.

Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
[ Viresh: Fixed rustfmtcheck errors ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2025-06-23 09:45:45 +05:30
Tamir Duberstein
dc35ddcf97 rust: enable clippy::ref_as_ptr lint
In Rust 1.78.0, Clippy introduced the `ref_as_ptr` lint [1]:

> Using `as` casts may result in silently changing mutability or type.

While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize.  It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#ref_as_ptr [1]
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/all/D8PGG7NTWB6U.3SS3A5LN4XWMN@proton.me/
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-6-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:09:32 +02:00
Tamir Duberstein
b7c8d7a8d2 rust: enable clippy::cast_lossless lint
Before Rust 1.29.0, Clippy introduced the `cast_lossless` lint [1]:

> Rust’s `as` keyword will perform many kinds of conversions, including
> silently lossy conversions. Conversion functions such as `i32::from`
> will only perform lossless conversions. Using the conversion functions
> prevents conversions from becoming silently lossy if the input types
> ever change, and makes it clear for people reading the code that the
> conversion is lossless.

While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize.  It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless [1]
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/all/D8ORTXSUTKGL.1KOJAGBM8F8TN@proton.me/
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Acked-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-5-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:09:25 +02:00
Tamir Duberstein
5e30550558 rust: enable clippy::as_underscore lint
In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]:

> The conversion might include lossy conversion or a dangerous cast that
> might go undetected due to the type being inferred.
>
> The lint is allowed by default as using `_` is less wordy than always
> specifying the type.

Always specifying the type is especially helpful in function call
contexts where the inferred type may change at a distance. Specifying
the type also allows Clippy to spot more cases of `useless_conversion`.

The primary downside is the need to specify the type in trivial getters.
There are 4 such functions: 3 have become slightly less ergonomic, 1 was
revealed to be a `useless_conversion`.

While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize.  It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com
[ Changed `isize` to `c_long`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:09:17 +02:00
Tamir Duberstein
23773bd8da rust: enable clippy::as_ptr_cast_mut lint
In Rust 1.66.0, Clippy introduced the `as_ptr_cast_mut` lint [1]:

> Since `as_ptr` takes a `&self`, the pointer won’t have write
> permissions unless interior mutability is used, making it unlikely
> that having it as a mutable pointer is correct.

There is only one affected callsite, and the change amounts to replacing
`as _` with `.cast_mut().cast()`. This doesn't change the semantics, but
is more descriptive of what's going on.

Apply this change and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_ptr_cast_mut [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-3-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:09:09 +02:00
Tamir Duberstein
d8c9e735f1 rust: enable clippy::ptr_cast_constness lint
In Rust 1.72.0, Clippy introduced the `ptr_cast_constness` lint [1]:

> Though `as` casts between raw pointers are not terrible,
> `pointer::cast_mut` and `pointer::cast_const` are safer because they
> cannot accidentally cast the pointer to another type.

There are only 3 affected sites:
- `*mut T as *const U as *mut U` becomes `(*mut T).cast()`.
- `&self as *const Self as *mut Self` becomes
  `core::ptr::from_ref(self).cast_mut()`.
- `*const T as *mut _` becommes `(*const T).cast_mut()`.

Apply these changes and enable the lint -- no functional change
intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_cast_constness [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-2-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:08:50 +02:00
Tamir Duberstein
fcad9bbf9e rust: enable clippy::ptr_as_ptr lint
In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]:

> Though `as` casts between raw pointers are not terrible,
> `pointer::cast` is safer because it cannot accidentally change the
> pointer's mutability, nor cast the pointer to other types like `usize`.

There are a few classes of changes required:
- Modules generated by bindgen are marked
  `#[allow(clippy::ptr_as_ptr)]`.
- Inferred casts (` as _`) are replaced with `.cast()`.
- Ascribed casts (` as *... T`) are replaced with `.cast::<T>()`.
- Multistep casts from references (` as *const _ as *const T`) are
  replaced with `core::ptr::from_ref(&x).cast()` with or without `::<T>`
  according to the previous rules. The `core::ptr::from_ref` call is
  required because `(x as *const _).cast::<T>()` results in inference
  failure.
- Native literal C strings are replaced with `c_str!().as_char_ptr()`.
- `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut
  T)`.cast();` since pointer to pointer can be confusing.

Apply these changes and enable the lint -- no functional change
intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-1-f43b024581e8@gmail.com
[ Added `.cast()` for `opp`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:08:42 +02:00
Onur Özkan
2a7b4b228c rust: replace literals with constants in clk::Hertz
Replaces repeated numeric literals in `Hertz` conversions
with named constants.

Signed-off-by: Onur Özkan <work@onurozkan.dev>
Link: https://lore.kernel.org/r/20250618092810.29370-1-work@onurozkan.dev
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2025-06-19 12:48:41 -07:00
Onur Özkan
b112dfc74b rust: shorten con_ids in get methods in clk module
Converts `if-else` blocks into one line code using `map_or`
for simplicity.

Signed-off-by: Onur Özkan <work@onurozkan.dev>
Link: https://lore.kernel.org/r/20250618093508.16343-1-work@onurozkan.dev
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2025-06-19 12:42:38 -07:00
Onur Özkan
bbbaea850e rust: make clk::Hertz methods const
Marks `Hertz` methods as `const` to make them available
for `const` contexts. This can be useful when defining
static/compile-time frequency parameters in drivers/subsystems.

Signed-off-by: Onur Özkan <work@onurozkan.dev>
Link: https://lore.kernel.org/r/20250618091442.29104-1-work@onurozkan.dev
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2025-06-19 12:42:26 -07:00
Abhinav Ananthu
10bb7f09e3 rust: cpufreq: Ensure C ABI compatibility in all unsafe
Update all `unsafe extern "C"` callback functions in the cpufreq module to
use `kernel::ffi` types (`c_int`, `c_uint`, etc.) instead of Rust-native
types like `i32`, `u32`, or `usize`.

This change ensures that all Rust callbacks have signatures that are
ABI-compatible with their corresponding C counterparts, which is critical
for FFI correctness and safety.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1170
Signed-off-by: Abhinav Ananthu <abhinav.ogl@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2025-06-19 13:25:46 +05:30
Linus Torvalds
229f135e06 Merge tag 'driver-core-6.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core
Pull driver core fixes from Danilo Krummrich:

 - Fix a race condition in Devres::drop(). This depends on two other
   patches:
     - (Minimal) Rust abstractions for struct completion
     - Let Revocable indicate whether its data is already being revoked

 - Fix Devres to avoid exposing the internal Revocable

 - Add .mailmap entry for Danilo Krummrich

 - Add Madhavan Srinivasan to embargoed-hardware-issues.rst

* tag 'driver-core-6.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core:
  Documentation: embargoed-hardware-issues.rst: Add myself for Power
  mailmap: add entry for Danilo Krummrich
  rust: devres: do not dereference to the internal Revocable
  rust: devres: fix race in Devres::drop()
  rust: revocable: indicate whether `data` has been revoked already
  rust: completion: implement initial abstraction
2025-06-18 14:31:16 -07:00
Alexandre Courbot
f86c0036c7 rust: alloc: implement Borrow and BorrowMut for KBox
Implement `Borrow<T>` and `BorrowMut<T>` for `KBox<T>`. This allows
`KBox<T>` to be used in generic APIs asking for types implementing those
traits. `T` and `&mut T` also implement those traits allowing users to
use either owned, borrowed and heap-owned values.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250616-borrow_impls-v4-3-36f9beb3fe6a@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-18 23:09:41 +02:00
Alexandre Courbot
c09a8ac1cd rust: alloc: implement Borrow and BorrowMut for Vec
Implement `Borrow<[T]>` and `BorrowMut<[T]>` for `Vec<T>`. This allows
`Vec<T>` to be used in generic APIs asking for types implementing those
traits. `[T; N]` and `&mut [T]` also implement those traits allowing
users to use either owned, borrowed and heap-owned values.

The implementation leverages `as_slice` and `as_mut_slice`.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250616-borrow_impls-v4-1-36f9beb3fe6a@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-18 23:09:21 +02:00
FUJITA Tomonori
cc6d1098b4 rust: time: Add ktime_get() to ClockSource trait
Introduce the ktime_get() associated function to the ClockSource
trait, allowing each clock source to specify how it retrieves the
current time. This enables Instant::now() to be implemented
generically using the type-level ClockSource abstraction.

This change enhances the type safety and extensibility of timekeeping
by statically associating time retrieval mechanisms with their
respective clock types. It also reduces the reliance on hardcoded
clock logic within Instant.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://lore.kernel.org/r/20250610093258.3435874-4-fujita.tomonori@gmail.com
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2025-06-16 15:02:29 +02:00
FUJITA Tomonori
768dfbfc98 rust: time: Make Instant generic over ClockSource
Refactor the Instant type to be generic over a ClockSource type
parameter, enabling static enforcement of clock correctness across
APIs that deal with time. Previously, the clock source was implicitly
fixed (typically CLOCK_MONOTONIC), and developers had to ensure
compatibility manually.

This design eliminates runtime mismatches between clock sources, and
enables stronger type-level guarantees throughout the timer subsystem.

Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://lore.kernel.org/r/20250610093258.3435874-3-fujita.tomonori@gmail.com
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2025-06-16 15:01:56 +02:00
FUJITA Tomonori
1664a671be rust: time: Replace ClockId enum with ClockSource trait
Replace the ClockId enum with a trait-based abstraction called
ClockSource. This change enables expressing clock sources as types and
leveraging the Rust type system to enforce clock correctness at
compile time.

This also sets the stage for future generic abstractions over Instant
types such as Instant<C>.

Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://lore.kernel.org/r/20250610093258.3435874-2-fujita.tomonori@gmail.com
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2025-06-16 15:01:37 +02:00
FUJITA Tomonori
1b7bbd5975 rust: time: Avoid 64-bit integer division on 32-bit architectures
Avoid 64-bit integer division that 32-bit architectures don't
implement generally. This uses ktime_to_us() and ktime_to_ms()
instead.

The time abstraction needs i64 / u32 division so C's div_s64() can be
used but ktime_to_us() and ktime_to_ms() provide a simpler solution
for this time abstraction problem on 32-bit architectures.

32-bit ARM is the only 32-bit architecture currently supported by
Rust. Using the cfg attribute, only 32-bit architectures will call
ktime_to_us() and ktime_to_ms(), while the other 64-bit architectures
will continue to use the current code as-is to avoid the overhead.

One downside of calling the C's functions is that the as_micros/millis
methods can no longer be const fn. We stick with the simpler approach
unless there's a compelling need for a const fn.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250502004524.230553-1-fujita.tomonori@gmail.com
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2025-06-16 15:01:15 +02:00
Linus Torvalds
588adb24b7 Merge tag 'rust-fixes-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull Rust fix from Miguel Ojeda:

  - 'hrtimer': fix future compile error when the 'impl_has_hr_timer!'
    macro starts to get called

* tag 'rust-fixes-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
  rust: time: Fix compile error in impl_has_hr_timer macro
2025-06-14 08:38:34 -07:00
Danilo Krummrich
20c96ed278 rust: devres: do not dereference to the internal Revocable
We can't expose direct access to the internal Revocable, since this
allows users to directly revoke the internal Revocable without Devres
having the chance to synchronize with the devres callback -- we have to
guarantee that the internal Revocable has been fully revoked before
the device is fully unbound.

Hence, remove the corresponding Deref implementation and, instead,
provide indirect accessors for the internal Revocable.

Note that we can still support Devres::revoke() by implementing the
required synchronization (which would be almost identical to the
synchronization in Devres::drop()).

Fixes: 76c01ded72 ("rust: add devres abstraction")
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250611174827.380555-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 23:48:53 +02:00
Danilo Krummrich
f744201c61 rust: devres: fix race in Devres::drop()
In Devres::drop() we first remove the devres action and then drop the
wrapped device resource.

The design goal is to give the owner of a Devres object control over when
the device resource is dropped, but limit the overall scope to the
corresponding device being bound to a driver.

However, there's a race that was introduced with commit 8ff656643d
("rust: devres: remove action in `Devres::drop`"), but also has been
(partially) present from the initial version on.

In Devres::drop(), the devres action is removed successfully and
subsequently the destructor of the wrapped device resource runs.
However, there is no guarantee that the destructor of the wrapped device
resource completes before the driver core is done unbinding the
corresponding device.

If in Devres::drop(), the devres action can't be removed, it means that
the devres callback has been executed already, or is still running
concurrently. In case of the latter, either Devres::drop() wins revoking
the Revocable or the devres callback wins revoking the Revocable. If
Devres::drop() wins, we (again) have no guarantee that the destructor of
the wrapped device resource completes before the driver core is done
unbinding the corresponding device.

CPU0					CPU1
------------------------------------------------------------------------
Devres::drop() {			Devres::devres_callback() {
   self.data.revoke() {			   this.data.revoke() {
      is_available.swap() == true
					      is_available.swap == false
					   }
					}

					// [...]
					// device fully unbound
      drop_in_place() {
         // release device resource
      }
   }
}

Depending on the specific device resource, this can potentially lead to
user-after-free bugs.

In order to fix this, implement the following logic.

In the devres callback, we're always good when we get to revoke the
device resource ourselves, i.e. Revocable::revoke() returns true.

If Revocable::revoke() returns false, it means that Devres::drop(),
concurrently, already drops the device resource and we have to wait for
Devres::drop() to signal that it finished dropping the device resource.

Note that if we hit the case where we need to wait for the completion of
Devres::drop() in the devres callback, it means that we're actually
racing with a concurrent Devres::drop() call, which already started
revoking the device resource for us. This is rather unlikely and means
that the concurrent Devres::drop() already started doing our work and we
just need to wait for it to complete it for us. Hence, there should not
be any additional overhead from that.

(Actually, for now it's even better if Devres::drop() does the work for
us, since it can bypass the synchronize_rcu() call implied by
Revocable::revoke(), but this goes away anyways once I get to implement
the split devres callback approach, which allows us to first flip the
atomics of all registered Devres objects of a certain device, execute a
single synchronize_rcu() and then drop all revocable objects.)

In Devres::drop() we try to revoke the device resource. If that is *not*
successful, it means that the devres callback already did and we're good.

Otherwise, we try to remove the devres action, which, if successful,
means that we're good, since the device resource has just been revoked
by us *before* we removed the devres action successfully.

If the devres action could not be removed, it means that the devres
callback must be running concurrently, hence we signal that the device
resource has been revoked by us, using the completion.

This makes it safe to drop a Devres object from any task and at any point
of time, which is one of the design goals.

Fixes: 76c01ded72 ("rust: add devres abstraction")
Reported-by: Alice Ryhl <aliceryhl@google.com>
Closes: https://lore.kernel.org/lkml/aD64YNuqbPPZHAa5@google.com/
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250612121817.1621-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 23:47:53 +02:00
Danilo Krummrich
4b76fafb20 rust: revocable: indicate whether data has been revoked already
Return a boolean from Revocable::revoke() and Revocable::revoke_nosync()
to indicate whether the data has been revoked already.

Return true if the data hasn't been revoked yet (i.e. this call revoked
the data), false otherwise.

This is required by Devres in order to synchronize the completion of the
revoke process.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250612121817.1621-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 23:46:59 +02:00
Danilo Krummrich
1b56e765bf rust: completion: implement initial abstraction
Implement a minimal abstraction for the completion synchronization
primitive.

This initial abstraction only adds complete_all() and
wait_for_completion(), since that is what is required for the subsequent
Devres patch.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250612121817.1621-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 23:46:56 +02:00
Remo Senekowitsch
2db611374c rust: device: Implement accessors for firmware properties
Add methods to FwNode for reading several firmware property types like
strings, integers and arrays.

Most types are read with the generic `property_read` method. There are
two exceptions:

* `property_read_bool` cannot fail, so the fallible function signature
  of `property_read` would not make sense for reading booleans.

* `property_read_array_vec` can fail because of a dynamic memory
  allocation. This error must be handled separately, leading to a
  different function signature than `property_read`.

The traits `Property` and `PropertyInt` drive the generic behavior
of `property_read`. `PropertyInt` is necessary to associate
specific integer types with the C functions to read them. While
there is a C function to read integers of generic sizes called
`fwnode_property_read_int_array`, it was preferred not to make this
public.

Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Co-developed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250611102908.212514-7-remo@buenzli.dev
[ Properly include kernel::device::private::Sealed; add explicit type
  annotations for core::mem::transmute(). - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 00:58:53 +02:00
Remo Senekowitsch
9bd791d941 rust: device: Introduce PropertyGuard
This abstraction is a way to force users to specify whether a property
is supposed to be required or not. This allows us to move error
logging of missing required properties into core, preventing a lot of
boilerplate in drivers.

It will be used by upcoming methods for reading device properties.

Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250611102908.212514-6-remo@buenzli.dev
[ Use prelude::* to avoid build failure; move PropertyGuard below Display
  impl of FwNode. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 00:58:53 +02:00
Remo Senekowitsch
ecea245981 rust: device: Enable printing fwnode name and path
Add two new public methods `display_name` and `display_path` to
`FwNode`. They can be used by driver authors for logging purposes. In
addition, they will be used by core property abstractions for automatic
logging, for example when a driver attempts to read a required but
missing property.

Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250611102908.212514-5-remo@buenzli.dev
[ Remove #[expect(dead_code)] from FwNode::from_raw(). - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 00:58:52 +02:00
Remo Senekowitsch
d3393e8450 rust: device: Move property_present() to FwNode
The new FwNode abstraction will be used for accessing all device
properties.

It would be possible to duplicate the methods on the device itself, but
since some of the methods on Device would have different type sigatures
as the ones on FwNode, this would only lead to inconsistency and
confusion. For this reason, property_present is removed from Device and
existing users are updated.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250611102908.212514-4-remo@buenzli.dev
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 00:58:52 +02:00
Remo Senekowitsch
658f23b592 rust: device: Enable accessing the FwNode of a Device
Subsequent patches will add methods for reading properties to FwNode.
The first step to accessing these methods will be to access the "root"
FwNode of a Device.

Add the method `fwnode` to `Device`.

Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250611102908.212514-3-remo@buenzli.dev
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 00:58:51 +02:00
Remo Senekowitsch
a2801affa7 rust: device: Create FwNode abstraction for accessing device properties
Accessing device properties is currently done via methods on `Device`
itself, using bindings to device_property_* functions. This is
sufficient for the existing method property_present. However, it's not
sufficient for other device properties we want to access. For example,
iterating over child nodes of a device will yield a fwnode_handle.
That's not a device, so it wouldn't be possible to read the properties
of that child node. Thus, we need an abstraction over fwnode_handle and
methods for reading its properties.

Add a struct FwNode which abstracts over the C struct fwnode_handle.
Implement its reference counting analogous to other Rust abstractions
over reference-counted C structs.

Subsequent patches will add functionality to access FwNode and read
properties with it.

Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250611102908.212514-2-remo@buenzli.dev
[ Add temporary #[expect(dead_code)] to avoid a warning. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-12 23:56:42 +02:00
Viresh Kumar
c7f005f70d rust: cpu: Add CpuId::current() to retrieve current CPU ID
Introduce `CpuId::current()`, a constructor that wraps the C function
`raw_smp_processor_id()` to retrieve the current CPU identifier without
guaranteeing stability.

This function should be used only when the caller can ensure that
the CPU ID won't change unexpectedly due to preemption or migration.

Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
2025-06-12 10:31:28 +05:30
Viresh Kumar
33db8c97b4 rust: Use CpuId in place of raw CPU numbers
Use the newly defined `CpuId` abstraction instead of raw CPU numbers.

This also fixes a doctest failure for configurations where `nr_cpu_ids <
4`.

The C `cpumask_{set|clear}_cpu()` APIs emit a warning when given an
invalid CPU number — but only if `CONFIG_DEBUG_PER_CPU_MAPS=y` is set.

Meanwhile, `cpumask_weight()` only considers CPUs up to `nr_cpu_ids`,
which can cause inconsistencies: a CPU number greater than `nr_cpu_ids`
may be set in the mask, yet the weight calculation won't reflect it.

This leads to doctest failures when `nr_cpu_ids < 4`, as the test tries
to set CPUs 2 and 3:

  rust_doctest_kernel_cpumask_rs_0.location: rust/kernel/cpumask.rs:180
  rust_doctest_kernel_cpumask_rs_0: ASSERTION FAILED at rust/kernel/cpumask.rs:190

Fixes: 8961b8cb30 ("rust: cpumask: Add initial abstractions")
Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://lore.kernel.org/rust-for-linux/CANiq72k3ozKkLMinTLQwvkyg9K=BeRxs1oYZSKhJHY-veEyZdg@mail.gmail.com/
Reported-by: Andreas Hindborg <a.hindborg@kernel.org>
Closes: https://lore.kernel.org/all/87qzzy3ric.fsf@kernel.org/
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
2025-06-12 10:31:28 +05:30
Viresh Kumar
ebf2e500e0 rust: cpu: Introduce CpuId abstraction
This adds abstraction for representing a CPU identifier.

Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
2025-06-12 08:45:19 +05:30
Miguel Ojeda
f744a5b68e rust: init: remove doctest's Error::from_errno workaround
Since commit 5ed1474734 ("rust: error: make conversion functions
public"), `Error::from_errno` is public.

Thus remove the workaround added in commit a30e94c296 ("rust: init:
make doctests compilable/testable").

Suggested-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/all/20250526152914.2453949-2-ojeda@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>
2025-06-11 21:13:57 +02:00
Miguel Ojeda
d2b7313fa2 rust: init: re-enable doctests
Commit a30e94c296 ("rust: init: make doctests compilable/testable")
made these tests buildable among others, but eventually the pin-init
crate was made into its own crate [1] and the tests were marked as
`ignore` in commit 206dea39e5 ("rust: init: disable doctests").

A few other bits got changed in that reorganization, e.g. the
`clippy::missing_safety_doc` was removed and the `expect` use.

Since there is no reason not to build/test them, re-enable them.

In order to do so, tweak a few bits to keep the build clean, and also use
again `expect` since this is one of those places where we can actually
do so.

Link: https://lore.kernel.org/all/20250308110339.2997091-1-benno.lossin@proton.me/ [1]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/all/20250526152914.2453949-1-ojeda@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>
2025-06-11 21:13:57 +02:00
Benno Lossin
e832374cca rust: pin-init: change blanket impls for [Pin]Init and add one for Result<T, E>
Remove the error from the blanket implementations `impl<T, E> Init<T, E>
for T` (and also for `PinInit`). Add implementations for `Result<T, E>`.

This allows one to easily construct (un)conditional failing
initializers. It also improves the compatibility with APIs that do not
use pin-init, because users can supply a `Result<T, E>` to a  function
taking an `impl PinInit<T, E>`.

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Link: 58612514b2
[ Also fix a compile error in block. - Benno ]
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/all/20250529081027.297648-2-lossin@kernel.org
[ Add title prefix `rust: pin-init`. - Benno ]
Signed-off-by: Benno Lossin <lossin@kernel.org>
2025-06-11 21:13:56 +02:00
Benno Lossin
101b7cf006 rust: pin-init: rename zeroed to init_zeroed
The name `zeroed` is a much better fit for a function that returns the
type by-value.

Link: 7dbe38682c
[ also rename uses in `rust/kernel/init.rs` - Benno]
Link: https://lore.kernel.org/all/20250523145125.523275-2-lossin@kernel.org
[ Fix wrong replacement of `mem::zeroed` in the definition of `trait
  Zeroable`. - Benno ]
[ Also change occurrences of `zeroed` in `configfs.rs` - Benno ]
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Benno Lossin <lossin@kernel.org>
2025-06-11 21:13:56 +02:00