Commit Graph

888 Commits

Author SHA1 Message Date
Danilo Krummrich
18ebb25dfa rust: pci: implement Driver::unbind()
Currently, there's really only one core callback for drivers, which is
probe().

Now, this isn't entirely true, since there is also the drop() callback of
the driver type (serving as the driver's private data), which is returned
by probe() and is dropped in remove().

On the C side remove() mainly serves two purposes:

  (1) Tear down the device that is operated by the driver, e.g. call bus
      specific functions, write I/O memory to reset the device, etc.

  (2) Free the resources that have been allocated by a driver for a
      specific device.

The drop() callback mentioned above is intended to cover (2) as the Rust
idiomatic way.

However, it is partially insufficient and inefficient to cover (1)
properly, since drop() can't be called with additional arguments, such as
the reference to the corresponding device that has the correct device
context, i.e. the Core device context.

This makes it inefficient (but not impossible) to access device
resources, e.g. to write device registers, and impossible to call device
methods, which are only accessible under the Core device context.

In order to solve this, add an additional callback for (1), which we
call unbind().

The reason for calling it unbind() is that, unlike remove(), it is *only*
meant to be used to perform teardown operations on the device (1), but
*not* to release resources (2).

Link: https://lore.kernel.org/r/20250621195118.124245-8-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:33 +02:00
Danilo Krummrich
4be5f3fff1 rust: platform: implement Driver::unbind()
Currently, there's really only one core callback for drivers, which is
probe().

Now, this isn't entirely true, since there is also the drop() callback of
the driver type (serving as the driver's private data), which is returned
by probe() and is dropped in remove().

On the C side remove() mainly serves two purposes:

  (1) Tear down the device that is operated by the driver, e.g. call bus
      specific functions, write I/O memory to reset the device, etc.

  (2) Free the resources that have been allocated by a driver for a
      specific device.

The drop() callback mentioned above is intended to cover (2) as the Rust
idiomatic way.

However, it is partially insufficient and inefficient to cover (1)
properly, since drop() can't be called with additional arguments, such as
the reference to the corresponding device that has the correct device
context, i.e. the Core device context.

This makes it inefficient (but not impossible) to access device
resources, e.g. to write device registers, and impossible to call device
methods, which are only accessible under the Core device context.

In order to solve this, add an additional callback for (1), which we
call unbind().

The reason for calling it unbind() is that, unlike remove(), it is *only*
meant to be used to perform teardown operations on the device (1), but
*not* to release resources (2).

Link: https://lore.kernel.org/r/20250621195118.124245-7-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:33 +02:00
Danilo Krummrich
c46f60246f rust: auxiliary: use generic device drvdata accessors
Take advantage of the generic drvdata accessors of the generic Device
type.

While at it, use from_result() instead of match.

Link: https://lore.kernel.org/r/20250621195118.124245-6-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:33 +02:00
Danilo Krummrich
4231712c8e rust: pci: use generic device drvdata accessors
Take advantage of the generic drvdata accessors of the generic Device
type.

While at it, use from_result() instead of match.

Link: https://lore.kernel.org/r/20250621195118.124245-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:33 +02:00
Danilo Krummrich
f0a68a912c rust: platform: use generic device drvdata accessors
Take advantage of the generic drvdata accessors of the generic Device
type.

While at it, use from_result() instead of match.

Link: https://lore.kernel.org/r/20250621195118.124245-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:33 +02:00
Danilo Krummrich
880dec12a2 rust: device: add drvdata accessors
Implement generic accessors for the private data of a driver bound to a
device.

Those accessors should be used by bus abstractions from their
corresponding core callbacks, such as probe(), remove(), etc.

Implementing them for device::CoreInternal guarantees that driver's can't
interfere with the logic implemented by the bus abstraction.

Acked-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250621195118.124245-3-dakr@kernel.org
[ Improve safety comment as proposed by Benno. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:33 +02:00
Danilo Krummrich
fa7486d3f9 rust: device: introduce device::CoreInternal
Introduce an internal device context, which is semantically equivalent
to the Core device context, but reserved for bus abstractions.

This allows implementing methods for the Device type, which are limited
to be used within the core context of bus abstractions, i.e. restrict
the availability for drivers.

Link: https://lore.kernel.org/r/20250621195118.124245-2-dakr@kernel.org
[ Rename device::Internal to device::CoreInternal. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-09 00:04:05 +02:00
Rahul Rameshbabu
5cddd546df rust: pci: fix documentation related to Device instances
Device instances in the pci crate represent a valid struct pci_dev, not a
struct device.

Fixes: 7b948a2af6 ("rust: pci: fix unrestricted &mut pci::Device")
Signed-off-by: Rahul Rameshbabu <sergeantsagara@protonmail.com>
Link: https://lore.kernel.org/r/20250706035944.18442-3-sergeantsagara@protonmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-07 14:32:09 +02:00
Tamir Duberstein
6d16cd5769 rust: devres: remove unused import
As far as I can tell, `c_str` was never used, hence remove it.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Link: https://lore.kernel.org/r/20250704-cstr-include-devres-v1-1-4ee9e56fca09@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-05 17:07:24 +02:00
Tamir Duberstein
65f8f0d4e0 rust: auxiliary: remove unnecessary import
`kernel::str::CStr` is included in the prelude.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Link: https://lore.kernel.org/r/20250704-cstr-include-aux-v1-1-e1a404ae92ac@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-05 17:07:24 +02:00
Tamir Duberstein
8ae33576ea rust: platform: remove unnecessary import
`kernel::str::CStr` is included in the prelude.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Link: https://lore.kernel.org/r/20250704-cstr-include-platform-v1-1-ff7803ee7a81@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-07-05 17:07:24 +02:00
Miguel Ojeda
97ba207a99 rust: acpi: remove unneeded cast to clean future Clippy warning
A future Clippy warning, `clippy::as_underscore`, is getting enabled in
parallel in the rust-next tree:

    error: using `as _` conversion
      --> rust/kernel/acpi.rs:25:9
       |
    25 |         self.0.driver_data as _
       |         ^^^^^^^^^^^^^^^^^^^^^^-
       |                               |
       |                               help: consider giving the type explicitly: `usize`

The type is already `ulong`, which nowadays is always `usize`, so the
cast is unneeded. Thus remove it, which in turn will avoid the warning
in the future.

Other abstractions of device tables do not use a cast here either.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Link: https://lore.kernel.org/r/20250701174656.62205-1-ojeda@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-03 19:18:59 +02:00
Shankari Anand
b9ff1c2a26 rust: miscdevice: clarify invariant for MiscDeviceRegistration
Reword and expand the invariant documentation for `MiscDeviceRegistration`
to clarify what it means for the inner device to be "registered".
It expands to explain:
- `inner` points to a `miscdevice` registered via `misc_register`.
- This registration stays valid for the entire lifetime of the object.
- Deregistration is guaranteed on `Drop`, via `misc_deregister`.

Reported-by: Benno Lossin <lossin@kernel.org>
Closes: https://github.com/Rust-for-Linux/linux/issues/1168
Fixes: f893691e74 ("rust: miscdevice: add base miscdevice abstraction")
Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com>
Link: https://lore.kernel.org/r/20250626104520.563036-1-shankari.ak0208@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-01 11:21:10 +02:00
FUJITA Tomonori
9b5cdd5f40 rust: fix typo in #[repr(transparent)] comments
Fix a typo in several comments where `#[repr(transparent)]` was
mistakenly written as `#[repr(transparent)` (missing closing
bracket).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://lore.kernel.org/r/20250623225846.169805-1-fujita.tomonori@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-01 11:21:04 +02:00
Danilo Krummrich
f5d3ef25d2 rust: devres: get rid of Devres' inner Arc
So far Devres uses an inner memory allocation and reference count, i.e.
an inner Arc, in order to ensure that the devres callback can't run into
a use-after-free in case where the Devres object is dropped while the
devres callback runs concurrently.

Instead, use a completion in order to avoid a potential UAF: In
Devres::drop(), if we detect that we can't remove the devres action
anymore, we wait for the completion that is completed from the devres
callback. If, in turn, we were able to successfully remove the devres
action, we can just go ahead.

This, again, allows us to get rid of the internal Arc, and instead let
Devres consume an `impl PinInit<T, E>` in order to return an
`impl PinInit<Devres<T>, E>`, which enables us to get away with less
memory allocations.

Additionally, having the resulting explicit synchronization in
Devres::drop() prevents potential subtle undesired side effects of the
devres callback dropping the final Arc reference asynchronously within
the devres callback.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250626200054.243480-4-dakr@kernel.org
[ Move '# Invariants' below '# Examples'. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-28 18:08:50 +02:00
Danilo Krummrich
46ae8fd738 rust: devres: replace Devres::new_foreign_owned()
Replace Devres::new_foreign_owned() with devres::register().

The current implementation of Devres::new_foreign_owned() creates a full
Devres container instance, including the internal Revocable and
completion.

However, none of that is necessary for the intended use of giving full
ownership of an object to devres and getting it dropped once the given
device is unbound.

Hence, implement devres::register(), which is limited to consume the
given data, wrap it in a KBox and drop the KBox once the given device is
unbound, without any other synchronization.

Cc: Dave Airlie <airlied@redhat.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250626200054.243480-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-28 18:06:53 +02:00
Danilo Krummrich
ce7c22b2e1 rust: revocable: support fallible PinInit types
Currently, Revocable::new() only supports infallible PinInit
implementations, i.e. impl PinInit<T, Infallible>.

This has been sufficient so far, since users such as Devres do not
support fallibility.

Since this is about to change, make Revocable::new() generic over the
error type E.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250626200054.243480-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-28 18:06:52 +02:00
Danilo Krummrich
14648fc30e pin-init blanket implementation changes for v6.17
Remove the error from the blanket implementations for `[Pin]Init` and
 add implementations for `Result`.
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Merge tag 'pin-init-v6.17-result-blanket' of https://github.com/Rust-for-Linux/linux.git

pin-init blanket implementation changes for v6.17

Remove the error from the blanket implementations for `[Pin]Init` and
add implementations for `Result`.

(Subsequent Devres improvements depend on those pin-init features.)
2025-06-28 17:28:06 +02:00
Christian Schrefl
64888dfdfa rust: implement Wrapper<T> for Opaque<T>
Moves the implementation for `pin-init` from an associated function
to the trait function of the `Wrapper` trait and extends the
implementation to support pin-initializers with error types.

Adds a use for the `Wrapper` trait in `revocable.rs`, to use the new
`pin-init` function. This is currently the only usage in the kernel.

Reviewed-by: Gerald Wisböck <gerald.wisboeck@feather.ink>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Christian Schrefl <chrisi.schrefl@gmail.com>
Link: https://lore.kernel.org/r/20250610-b4-rust_miscdevice_registrationdata-v6-1-b03f5dfce998@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-28 14:58:08 +02:00
Danilo Krummrich
0dab138d0f rust: devres: require T: Send for Devres
Due to calling Revocable::revoke() from Devres::devres_callback() T may
be dropped from Devres::devres_callback() and hence must be Send.

Fix this by adding the corresponding bound to Devres and DevresInner.

Reported-by: Boqun Feng <boqun.feng@gmail.com>
Closes: https://lore.kernel.org/lkml/aFzI5L__OcB9hqdG@Mac.home/
Fixes: 76c01ded72 ("rust: add devres abstraction")
Reviewed-by: Boqun Feng <boqun.fenng@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250626132544.72866-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-28 14:55:22 +02:00
Igor Korotin
8411e6f06a rust: platform: Add ACPI match table support to Driver trait
Extend the `platform::Driver` trait to support ACPI device matching by
adding the `ACPI_ID_TABLE` constant.

This allows Rust platform drivers to define ACPI match tables alongside
their existing OF match tables. These changes mirror the existing OF
support and allow Rust platform drivers to match devices based on ACPI
identifiers.

Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://lore.kernel.org/r/20250620154334.298320-1-igor.korotin.linux@gmail.com
[ Use 'LNUXBEEF' as ACPI ID. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-26 23:26:15 +02:00
Igor Korotin
ec3ef2175e rust: platform: Set OF_ID_TABLE default to None in Driver trait
Provide a default value of `None` for `Driver::OF_ID_TABLE` to simplify
driver implementations.

Drivers that do not require OpenFirmware matching no longer need to
import the `of` module or define the constant explicitly.

This reduces unnecessary boilerplate and avoids pulling in unused
dependencies.

Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://lore.kernel.org/r/20250620154124.297158-1-igor.korotin.linux@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-26 23:26:15 +02:00
Igor Korotin
7a5cb145a9 rust: driver: Add ACPI id table support to Adapter trait
Extend the `Adapter` trait to support ACPI device identification.

This mirrors the existing Open Firmware (OF) support (`of_id_table`) and
enables Rust drivers to match and retrieve ACPI-specific device data
when `CONFIG_ACPI` is enabled.

To avoid breaking compilation, a stub implementation of `acpi_id_table()`
is added to the Platform adapter; the full implementation will be provided
in a subsequent patch.

Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://lore.kernel.org/r/20250620153914.295679-1-igor.korotin.linux@gmail.com
[ Fix clippy warning if #[cfg(not(CONFIG_OF))]; fix checkpatch.pl line
  length warnings. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-26 23:26:10 +02:00
Igor Korotin
0f549d2585 rust: driver: Consolidate Adapter::of_id_info methods using #[cfg]
Refactor the `of_id_info` methods in the `Adapter` trait to reduce
duplication. Previously, the method had two versions selected
via `#[cfg(...)]` and `#[cfg(not(...))]`. This change merges them into a
single method by using `#[cfg]` blocks within the method body.

Suggested-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://lore.kernel.org/r/20250620153656.294468-1-igor.korotin.linux@gmail.com
[ Fix clippy warning if #[cfg(not(CONFIG_OF))]; fix checkpatch.pl line
  length warnings. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-26 23:25:07 +02:00
Igor Korotin
a74931eb59 rust: acpi: add acpi::DeviceId abstraction
`acpi::DeviceId` is an abstraction around `struct acpi_device_id`.

Enable drivers to build ACPI device ID tables, to be consumed by the
corresponding bus abstractions, such as platform or I2C.

Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20250620152425.285683-1-igor.korotin.linux@gmail.com
[ Always inline DeviceId::new() and use &'static CStr; slightly reword
  commit message. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-26 23:22:17 +02:00
Danilo Krummrich
56a789f776 rust: device: implement FwNode::is_of_node()
Implement FwNode::is_of_node() in order to check whether a FwNode
instance is embedded in a struct device_node.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://lore.kernel.org/r/20250620151504.278766-1-igor.korotin.linux@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-25 18:10:12 +02:00
Remo Senekowitsch
c3e05bd15e rust: device: Add property_get_reference_args
Allow Rust code to read reference args from device properties. The
wrapper type `FwNodeReferenceArgs` allows callers to access the buffer
of read args safely.

Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250616154511.1862909-3-remo@buenzli.dev
[ Move up NArgs; refer to FwNodeReferenceArgs in NArgs doc-comment.
  - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-25 17:47:13 +02:00
Remo Senekowitsch
c942dba380 rust: device: Add child accessor and iterator
Allow Rust drivers to access children of a fwnode either by name or by
iterating over all of them.

In C, there is the function `fwnode_get_next_child_node` for iteration
and the macro `fwnode_for_each_child_node` that helps with handling the
pointers. Instead of a macro, a native iterator is used in Rust such
that regular for-loops can be used.

Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
Link: https://lore.kernel.org/r/20250616154511.1862909-2-remo@buenzli.dev
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-25 17:18:07 +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
Linus Torvalds
229f135e06 Driver core fixes for 6.16-rc3
- 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.
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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
Linus Torvalds
588adb24b7 Rust fixes for v6.16
'kernel' crate:
 
   - 'hrtimer': fix future compile error when the 'impl_has_hr_timer!'
     macro starts to get called.
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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
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
8b3d955f72 rust: pin-init: improve safety documentation for impl<T> [Pin]Init<T> for T
The inner SAFETY comments were missing since commit 5cfe7bef6751 ("rust:
enable `clippy::undocumented_unsafe_blocks` lint").

Also rework the implementation of `__pinned_init` to better justify the
SAFETY comment.

Link: df925b2e27
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/all/20250529081027.297648-1-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>
2025-06-11 21:13:56 +02:00
FUJITA Tomonori
5b2d595efb rust: time: Fix compile error in impl_has_hr_timer macro
Fix a compile error in the `impl_has_hr_timer!` macro as follows:

error[E0599]: no method named cast_mut found for raw pointer *mut Foo in the current scope

The `container_of!` macro already returns a mutable pointer when used
in a `*mut T` context so the `.cast_mut()` method is not available.

[ We missed this one because there is no caller yet and it is
  a macro. - Miguel ]

Fixes: 74d6a606c2 ("rust: retain pointer mut-ness in `container_of!`")
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250606020505.3186533-1-fujita.tomonori@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-10 20:11:36 +02:00
Viresh Kumar
4823a58093 cpufreq: Convert /// SAFETY lines to # Safety sections
Replace `/// SAFETY` comments in doc comments with proper `# Safety`
sections, as per rustdoc conventions.

Also mark the C FFI callbacks as `unsafe` to correctly reflect their
safety requirements.

Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://github.com/Rust-for-Linux/linux/issues/1169
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2025-06-10 16:38:56 +05:30
Linus Torvalds
c26f4fbd58 Char/Misc/IIO pull request for 6.16-rc1
Here is the big char/misc/iio and other small driver subsystem pull
 request for 6.16-rc1.
 
 Overall, a lot of individual changes, but nothing major, just the normal
 constant forward progress of new device support and cleanups to existing
 subsystems.  Highlights in here are:
   - Large IIO driver updates and additions and device tree changes
   - Android binder bugfixes and logfile fixes
   - mhi driver updates
   - comedi driver updates
   - counter driver updates and additions
   - coresight driver updates and additions
   - echo driver removal as there are no in-kernel users of it
   - nvmem driver updates
   - spmi driver updates
   - new amd-sbi driver "subsystem" and drivers added
   - rust miscdriver binding documentation fix
   - other small driver fixes and updates (uio, w1, acrn, hpet, xillybus,
     cardreader drivers, fastrpc and others.)
 
 All of these have been in linux-next for quite a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char / misc / iio driver updates from Greg KH:
 "Here is the big char/misc/iio and other small driver subsystem pull
  request for 6.16-rc1.

  Overall, a lot of individual changes, but nothing major, just the
  normal constant forward progress of new device support and cleanups to
  existing subsystems. Highlights in here are:

   - Large IIO driver updates and additions and device tree changes

   - Android binder bugfixes and logfile fixes

   - mhi driver updates

   - comedi driver updates

   - counter driver updates and additions

   - coresight driver updates and additions

   - echo driver removal as there are no in-kernel users of it

   - nvmem driver updates

   - spmi driver updates

   - new amd-sbi driver "subsystem" and drivers added

   - rust miscdriver binding documentation fix

   - other small driver fixes and updates (uio, w1, acrn, hpet,
     xillybus, cardreader drivers, fastrpc and others)

  All of these have been in linux-next for quite a while with no
  reported problems"

* tag 'char-misc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (390 commits)
  binder: fix yet another UAF in binder_devices
  counter: microchip-tcb-capture: Add watch validation support
  dt-bindings: iio: adc: Add ROHM BD79100G
  iio: adc: add support for Nuvoton NCT7201
  dt-bindings: iio: adc: add NCT7201 ADCs
  iio: chemical: Add driver for SEN0322
  dt-bindings: trivial-devices: Document SEN0322
  iio: adc: ad7768-1: reorganize driver headers
  iio: bmp280: zero-init buffer
  iio: ssp_sensors: optimalize -> optimize
  HID: sensor-hub: Fix typo and improve documentation
  iio: admv1013: replace redundant ternary operator with just len
  iio: chemical: mhz19b: Fix error code in probe()
  iio: adc: at91-sama5d2: use IIO_DECLARE_BUFFER_WITH_TS
  iio: accel: sca3300: use IIO_DECLARE_BUFFER_WITH_TS
  iio: adc: ad7380: use IIO_DECLARE_DMA_BUFFER_WITH_TS
  iio: adc: ad4695: rename AD4695_MAX_VIN_CHANNELS
  iio: adc: ad4695: use IIO_DECLARE_DMA_BUFFER_WITH_TS
  iio: introduce IIO_DECLARE_BUFFER_WITH_TS macros
  iio: make IIO_DMA_MINALIGN minimum of 8 bytes
  ...
2025-06-06 11:50:47 -07:00
Linus Torvalds
ec7714e494 Rust changes for v6.16
Toolchain and infrastructure:
 
  - KUnit '#[test]'s:
 
    - Support KUnit-mapped 'assert!' macros.
 
      The support that landed last cycle was very basic, and the
      'assert!' macros panicked since they were the standard library
      ones. Now, they are mapped to the KUnit ones in a similar way to
      how is done for doctests, reusing the infrastructure there.
 
      With this, a failing test like:
 
          #[test]
          fn my_first_test() {
              assert_eq!(42, 43);
          }
 
      will report:
 
          # my_first_test: ASSERTION FAILED at rust/kernel/lib.rs:251
          Expected 42 == 43 to be true, but is false
          # my_first_test.speed: normal
          not ok 1 my_first_test
 
    - Support tests with checked 'Result' return types.
 
      The return value of test functions that return a 'Result' will be
      checked, thus one can now easily catch errors when e.g. using the
      '?' operator in tests.
 
      With this, a failing test like:
 
          #[test]
          fn my_test() -> Result {
              f()?;
              Ok(())
          }
 
      will report:
 
          # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321
          Expected is_test_result_ok(my_test()) to be true, but is false
          # my_test.speed: normal
          not ok 1 my_test
 
    - Add 'kunit_tests' to the prelude.
 
  - Clarify the remaining language unstable features in use.
 
  - Compile 'core' with edition 2024 for Rust >= 1.87.
 
  - Workaround 'bindgen' issue with forward references to 'enum' types.
 
  - objtool: relax slice condition to cover more 'noreturn' functions.
 
  - Use absolute paths in macros referencing 'core' and 'kernel' crates.
 
  - Skip '-mno-fdpic' flag for bindgen in GCC 32-bit arm builds.
 
  - Clean some 'doc_markdown' lint hits -- we may enable it later on.
 
 'kernel' crate:
 
  - 'alloc' module:
 
    - 'Box': support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>' if
      'T' implements 'U'.
 
    - 'Vec': implement new methods (prerequisites for nova-core and
      binder): 'truncate', 'resize', 'clear', 'pop',
      'push_within_capacity' (with new error type 'PushError'),
      'drain_all', 'retain', 'remove' (with new error type
      'RemoveError'), insert_within_capacity' (with new error type
      'InsertError').
 
      In addition, simplify 'push' using 'spare_capacity_mut', split
      'set_len' into 'inc_len' and 'dec_len', add type invariant
      'len <= capacity' and simplify 'truncate' using 'dec_len'.
 
  - 'time' module:
 
    - Morph the Rust hrtimer subsystem into the Rust timekeeping
      subsystem, covering delay, sleep, timekeeping, timers. This new
      subsystem has all the relevant timekeeping C maintainers listed in
      the entry.
 
    - Replace 'Ktime' with 'Delta' and 'Instant' types to represent a
      duration of time and a point in time.
 
    - Temporarily add 'Ktime' to 'hrtimer' module to allow 'hrtimer' to
      delay converting to 'Instant' and 'Delta'.
 
  - 'xarray' module:
 
    - 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.
 
    - Allow 'ForeignOwnable' to carry information about the pointed-to
      type. This helps asserting alignment requirements for the pointer
      passed to the foreign language.
 
  - 'container_of!': retain pointer mut-ness and add a compile-time check
    of the type of the first parameter ('$field_ptr').
 
  - Support optional message in 'static_assert!'.
 
  - Add C FFI types (e.g. 'c_int') to the prelude.
 
  - 'str' module: simplify KUnit tests 'format!' macro, convert
    'rusttest' tests into KUnit, take advantage of the '-> Result'
    support in KUnit '#[test]'s.
 
  - 'list' module: add examples for 'List', fix path of 'assert_pinned!'
    (so far unused macro rule).
 
  - 'workqueue' module: remove 'HasWork::OFFSET'.
 
  - 'page' module: add 'inline' attribute.
 
 'macros' crate:
 
  - 'module' macro: place 'cleanup_module()' in '.exit.text' section.
 
 'pin-init' crate:
 
  - Add 'Wrapper<T>' trait for creating pin-initializers for wrapper
    structs with a structurally pinned value such as 'UnsafeCell<T>' or
    'MaybeUninit<T>'.
 
  - Add 'MaybeZeroable' derive macro to try to derive 'Zeroable', but
    not error if not all fields implement it. This is needed to derive
    'Zeroable' for all bindgen-generated structs.
 
  - Add 'unsafe fn cast_[pin_]init()' functions to unsafely change the
    initialized type of an initializer. These are utilized by the
    'Wrapper<T>' implementations.
 
  - Add support for visibility in 'Zeroable' derive macro.
 
  - Add support for 'union's in 'Zeroable' derive macro.
 
  - Upstream dev news: streamline CI, fix some bugs. Add new workflows
    to check if the user-space version and the one in the kernel tree
    have diverged. Use the issues tab [1] to track them, which should
    help folks report and diagnose issues w.r.t. 'pin-init' better.
 
      [1] https://github.com/rust-for-linux/pin-init/issues
 
 Documentation:
 
  - Testing: add docs on the new KUnit '#[test]' tests.
 
  - Coding guidelines: explain that '///' vs. '//' applies to private
    items too. Add section on C FFI types.
 
  - Quick Start guide: update Ubuntu instructions and split them into
    "25.04" and "24.04 LTS and older".
 
 And a few other cleanups and improvements.
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Merge tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - KUnit '#[test]'s:

      - Support KUnit-mapped 'assert!' macros.

        The support that landed last cycle was very basic, and the
        'assert!' macros panicked since they were the standard library
        ones. Now, they are mapped to the KUnit ones in a similar way to
        how is done for doctests, reusing the infrastructure there.

        With this, a failing test like:

            #[test]
            fn my_first_test() {
                assert_eq!(42, 43);
            }

        will report:

            # my_first_test: ASSERTION FAILED at rust/kernel/lib.rs:251
            Expected 42 == 43 to be true, but is false
            # my_first_test.speed: normal
            not ok 1 my_first_test

      - Support tests with checked 'Result' return types.

        The return value of test functions that return a 'Result' will
        be checked, thus one can now easily catch errors when e.g. using
        the '?' operator in tests.

        With this, a failing test like:

            #[test]
            fn my_test() -> Result {
                f()?;
                Ok(())
            }

        will report:

            # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321
            Expected is_test_result_ok(my_test()) to be true, but is false
            # my_test.speed: normal
            not ok 1 my_test

      - Add 'kunit_tests' to the prelude.

   - Clarify the remaining language unstable features in use.

   - Compile 'core' with edition 2024 for Rust >= 1.87.

   - Workaround 'bindgen' issue with forward references to 'enum' types.

   - objtool: relax slice condition to cover more 'noreturn' functions.

   - Use absolute paths in macros referencing 'core' and 'kernel'
     crates.

   - Skip '-mno-fdpic' flag for bindgen in GCC 32-bit arm builds.

   - Clean some 'doc_markdown' lint hits -- we may enable it later on.

  'kernel' crate:

   - 'alloc' module:

      - 'Box': support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>'
        if 'T' implements 'U'.

      - 'Vec': implement new methods (prerequisites for nova-core and
        binder): 'truncate', 'resize', 'clear', 'pop',
        'push_within_capacity' (with new error type 'PushError'),
        'drain_all', 'retain', 'remove' (with new error type
        'RemoveError'), insert_within_capacity' (with new error type
        'InsertError').

        In addition, simplify 'push' using 'spare_capacity_mut', split
        'set_len' into 'inc_len' and 'dec_len', add type invariant 'len
        <= capacity' and simplify 'truncate' using 'dec_len'.

   - 'time' module:

      - Morph the Rust hrtimer subsystem into the Rust timekeeping
        subsystem, covering delay, sleep, timekeeping, timers. This new
        subsystem has all the relevant timekeeping C maintainers listed
        in the entry.

      - Replace 'Ktime' with 'Delta' and 'Instant' types to represent a
        duration of time and a point in time.

      - Temporarily add 'Ktime' to 'hrtimer' module to allow 'hrtimer'
        to delay converting to 'Instant' and 'Delta'.

   - 'xarray' module:

      - 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.

      - Allow 'ForeignOwnable' to carry information about the pointed-to
        type. This helps asserting alignment requirements for the
        pointer passed to the foreign language.

   - 'container_of!': retain pointer mut-ness and add a compile-time
     check of the type of the first parameter ('$field_ptr').

   - Support optional message in 'static_assert!'.

   - Add C FFI types (e.g. 'c_int') to the prelude.

   - 'str' module: simplify KUnit tests 'format!' macro, convert
     'rusttest' tests into KUnit, take advantage of the '-> Result'
     support in KUnit '#[test]'s.

   - 'list' module: add examples for 'List', fix path of
     'assert_pinned!' (so far unused macro rule).

   - 'workqueue' module: remove 'HasWork::OFFSET'.

   - 'page' module: add 'inline' attribute.

  'macros' crate:

   - 'module' macro: place 'cleanup_module()' in '.exit.text' section.

  'pin-init' crate:

   - Add 'Wrapper<T>' trait for creating pin-initializers for wrapper
     structs with a structurally pinned value such as 'UnsafeCell<T>' or
     'MaybeUninit<T>'.

   - Add 'MaybeZeroable' derive macro to try to derive 'Zeroable', but
     not error if not all fields implement it. This is needed to derive
     'Zeroable' for all bindgen-generated structs.

   - Add 'unsafe fn cast_[pin_]init()' functions to unsafely change the
     initialized type of an initializer. These are utilized by the
     'Wrapper<T>' implementations.

   - Add support for visibility in 'Zeroable' derive macro.

   - Add support for 'union's in 'Zeroable' derive macro.

   - Upstream dev news: streamline CI, fix some bugs. Add new workflows
     to check if the user-space version and the one in the kernel tree
     have diverged. Use the issues tab [1] to track them, which should
     help folks report and diagnose issues w.r.t. 'pin-init' better.

       [1] https://github.com/rust-for-linux/pin-init/issues

  Documentation:

   - Testing: add docs on the new KUnit '#[test]' tests.

   - Coding guidelines: explain that '///' vs. '//' applies to private
     items too. Add section on C FFI types.

   - Quick Start guide: update Ubuntu instructions and split them into
     "25.04" and "24.04 LTS and older".

  And a few other cleanups and improvements"

* tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (78 commits)
  rust: list: Fix typo `much` in arc.rs
  rust: check type of `$ptr` in `container_of!`
  rust: workqueue: remove HasWork::OFFSET
  rust: retain pointer mut-ness in `container_of!`
  Documentation: rust: testing: add docs on the new KUnit `#[test]` tests
  Documentation: rust: rename `#[test]`s to "`rusttest` host tests"
  rust: str: take advantage of the `-> Result` support in KUnit `#[test]`'s
  rust: str: simplify KUnit tests `format!` macro
  rust: str: convert `rusttest` tests into KUnit
  rust: add `kunit_tests` to the prelude
  rust: kunit: support checked `-> Result`s in KUnit `#[test]`s
  rust: kunit: support KUnit-mapped `assert!` macros in `#[test]`s
  rust: make section names plural
  rust: list: fix path of `assert_pinned!`
  rust: compile libcore with edition 2024 for 1.87+
  rust: dma: add missing Markdown code span
  rust: task: add missing Markdown code spans and intra-doc links
  rust: pci: fix docs related to missing Markdown code spans
  rust: alloc: add missing Markdown code span
  rust: alloc: add missing Markdown code spans
  ...
2025-06-04 21:18:37 -07:00