`bindgen` currently generates the wrong type for an `enum` when there
is a forward reference to it. For instance:
enum E;
enum E { A };
generates:
pub const E_A: E = 0;
pub type E = i32;
instead of the expected:
pub const E_A: E = 0;
pub type E = ffi::c_uint;
The issue was reported to upstream `bindgen` [1].
Now, both GCC and Clang support silently these forward references to
`enum` types, unless `-Wpedantic` is passed, and it turns out that some
headers in the kernel depend on them.
Thus, depending on how the headers are included, which in turn may depend
on the kernel configuration or the architecture, we may get a different
type on the Rust side for a given C `enum`.
That can be quite confusing, to say the least, especially since
developers may only notice issues when building for other architectures
like in [2]. In particular, they may end up forcing a cast and adding
an `#[allow(clippy::unnecessary_cast)]` like it was done in commit
94e05a66ea ("rust: hrtimer: allow timer restart from timer handler"),
which isn't great.
Instead, let's have a section at the top of our `bindings_helper.h` that
`#include`s the headers with the affected types -- hopefully there are
not many cases and there is a single ordering that covers all cases.
This allows us to remove the cast and the `#[allow]`, thus keeping the
correct code in the source files. When the issue gets resolved in upstream
`bindgen` (and we update our minimum `bindgen` version), we can easily
remove this section at the top.
Link: https://github.com/rust-lang/rust-bindgen/issues/3179 [1]
Link: https://lore.kernel.org/rust-for-linux/87tt7md1s6.fsf@kernel.org/ [2]
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250325184309.97170-1-ojeda@kernel.org
[ Added extra paragraph on the comment to clarify that the workaround may
not be possible in some cases. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Introduce initial Rust abstractions for the cpufreq core. This includes
basic representations for cpufreq flags, relation types, and the cpufreq
table.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Introduce initial Rust abstractions for the Operating Performance Points
(OPP) framework. This includes bindings for `struct dev_pm_opp` and
`struct dev_pm_opp_data`, laying the groundwork for further OPP
integration.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
This implements cpu::from_cpu(), which returns a reference to
Device for a CPU. The C struct is created at initialization time for
CPUs and is never freed and so ARef isn't returned from this function.
The new helper will be used by Rust based cpufreq drivers.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Non-trivial C macros and inlined C functions cannot be used directly
in the Rust code and are used via functions ("helpers") that wrap
those so that they can be called from Rust.
In order to prepare for adding Rust abstractions for the clock APIs,
add clock helpers required by the Rust implementation.
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Pull XArray updates from Andreas Hindborg:
"Introduce Rust support for the 'xarray' data structure:
- Add a Rust abstraction for the 'xarray' data structure. This
abstraction allows Rust code to leverage the 'xarray' to store
types that implement 'ForeignOwnable'. This support is a dependency
for memory backing feature of the Rust null block driver, which is
waiting to be merged.
- Set up an entry in MAINTAINERS for the XArray Rust support. Patches
will go to the new Rust XArray tree and then via the Rust subsystem
tree for now.
'kernel' crate:
- Allow 'ForeignOwnable' to carry information about the pointed-to
type. This helps asserting alignment requirements for the pointer
passed to the foreign language."
* tag 'rust-xarray-for-v6.16' of https://github.com/Rust-for-Linux/linux:
MAINTAINERS: add entry for Rust XArray API
rust: xarray: Add an abstraction for XArray
rust: types: add `ForeignOwnable::PointedTo`
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 <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250502140237.1659624-4-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
DRM GEM is the DRM memory management subsystem used by most modern
drivers; add a Rust abstraction for DRM GEM.
This includes the BaseObject trait, which contains operations shared by
all GEM object classes.
Signed-off-by: Asahi Lina <lina@asahilina.net>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20250410235546.43736-8-dakr@kernel.org
[ Rework of GEM object abstractions
* switch to the Opaque<T> type
* fix (mutable) references to struct drm_gem_object (which in this
context is UB)
* drop all custom reference types in favor of AlwaysRefCounted
* bunch of minor changes and simplifications (e.g. IntoGEMObject
trait)
* write and fix safety and invariant comments
* remove necessity for and convert 'as' casts
* original source archive: https://archive.is/dD5SL
- Danilo ]
[ Fix missing CONFIG_DRM guards in rust/helpers/drm.c. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
A DRM File is the DRM counterpart to a kernel file structure,
representing an open DRM file descriptor.
Add a Rust abstraction to allow drivers to implement their own File types
that implement the DriverFile trait.
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Asahi Lina <lina@asahilina.net>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20250410235546.43736-7-dakr@kernel.org
[ Rework of drm::File
* switch to the Opaque<T> type
* fix (mutable) references to struct drm_file (which in this context
is UB)
* restructure and rename functions to align with common kernel
schemes
* write and fix safety and invariant comments
* remove necessity for and convert 'as' casts
* original source archive: https://archive.is/GH8oy
- Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Implement the DRM driver abstractions.
The `Driver` trait provides the interface to the actual driver to fill
in the driver specific data, such as the `DriverInfo`, driver features
and IOCTLs.
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Asahi Lina <lina@asahilina.net>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20250410235546.43736-4-dakr@kernel.org
[ MISC changes
* remove unnecessary DRM features; make remaining ones crate private
* add #[expect(unused)] to avoid warnings
* add sealed trait
* remove shmem::Object references
* original source archive: https://archive.is/Pl9ys
- Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
DRM drivers need to be able to declare which driver-specific ioctls they
support. Add an abstraction implementing the required types and a helper
macro to generate the ioctl definition inside the DRM driver.
Note that this macro is not usable until further bits of the abstraction
are in place (but it will not fail to compile on its own, if not called).
Signed-off-by: Asahi Lina <lina@asahilina.net>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20250410235546.43736-3-dakr@kernel.org
[ MISC fixes
* wrap raw_data in Opaque to avoid UB when creating a reference
* fix IOCTL sample declaration
* fix safety comment of IOCTL argument
* original source archive: https://archive.is/LqHDQ
- Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Implement the basic auxiliary abstractions required to implement a
driver matching an auxiliary device.
The design and implementation is analogous to PCI and platform and is
based on the generic device / driver abstractions.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250414131934.28418-4-dakr@kernel.org
[ Fix typos, `let _ =` => `drop()`, use `kernel::ffi`. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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<Box<_>>', '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<Box<T>>`
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<BStr>` for `[u8]` and `BStr`
rust: str: implement `Index` for `BStr`
rust: str: implement `PartialEq` for `BStr`
...
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
--> <linux>/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 <a.hindborg@kernel.org>
Reviewed-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
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 <ojeda@kernel.org>
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 <aliceryhl@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
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) <robh@kernel.org>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Link: https://lore.kernel.org/r/20241219170425.12036-15-dakr@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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) <robh@kernel.org>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Link: https://lore.kernel.org/r/20241219170425.12036-14-dakr@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <fujita.tomonori@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Link: https://lore.kernel.org/r/20241219170425.12036-10-dakr@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull char/misc/IIO/whatever driver subsystem updates from Greg KH:
"Here is the 'big and hairy' char/misc/iio and other small driver
subsystem updates for 6.13-rc1.
Loads of things in here, and even a fun merge conflict!
- rust misc driver bindings and other rust changes to make misc
drivers actually possible.
I think this is the tipping point, expect to see way more rust
drivers going forward now that these bindings are present. Next
merge window hopefully we will have pci and platform drivers
working, which will fully enable almost all driver subsystems to
start accepting (or at least getting) rust drivers.
This is the end result of a lot of work from a lot of people,
congrats to all of them for getting this far, you've proved many of
us wrong in the best way possible, working code :)
- IIO driver updates, too many to list individually, that subsystem
keeps growing and growing...
- Interconnect driver updates
- nvmem driver updates
- pwm driver updates
- platform_driver::remove() fixups, loads of them
- counter driver updates
- misc driver updates (keba?)
- binder driver updates and fixes
- loads of other small char/misc/etc driver updates and additions,
full details in the shortlog.
All of these have been in linux-next for a while, with no other
reported issues other than that merge conflict"
* tag 'char-misc-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (401 commits)
mei: vsc: Fix typo "maintstepping" -> "mainstepping"
firmware: Switch back to struct platform_driver::remove()
misc: isl29020: Fix the wrong format specifier
scripts/tags.sh: Don't tag usages of DEFINE_MUTEX
fpga: Switch back to struct platform_driver::remove()
mei: vsc: Improve error logging in vsc_identify_silicon()
mei: vsc: Do not re-enable interrupt from vsc_tp_reset()
dt-bindings: spmi: qcom,x1e80100-spmi-pmic-arb: Add SAR2130P compatible
dt-bindings: spmi: spmi-mtk-pmif: Add compatible for MT8188
spmi: pmic-arb: fix return path in for_each_available_child_of_node()
iio: Move __private marking before struct element priv in struct iio_dev
docs: iio: ad7380: add adaq4370-4 and adaq4380-4
iio: adc: ad7380: add support for adaq4370-4 and adaq4380-4
iio: adc: ad7380: use local dev variable to shorten long lines
iio: adc: ad7380: fix oversampling formula
dt-bindings: iio: adc: ad7380: add adaq4370-4 and adaq4380-4 compatible parts
bus: mhi: host: pci_generic: Use pcim_iomap_region() to request and map MHI BAR
bus: mhi: host: Switch trace_mhi_gen_tre fields to native endian
misc: atmel-ssc: Use of_property_present() for non-boolean properties
misc: keba: Add hardware dependency
...
Miguel Ojeda
Viresh Kumar
Andreas Hindborg
Tamir Duberstein
Asahi Lina
Danilo Krummrich
Linus Torvalds
Abdiel Janulgue
Alice Ryhl
Lyude Paul