Re: [PATCH v3] rust: ACPI: fix missing match data for PRP0001

Rafael J. Wysocki
2026-04-08T09:59:09Z

On Tue, Apr 7, 2026 at 11:42 PM Markus Probst <markus.probst@posteo.de> wrote:
>
> Export `acpi_of_match_device` function and use it to match the of device
> table against ACPI PRP0001 in Rust.
>
> This fixes id_info being None on ACPI PRP0001 devices.
>
> Using `device_get_match_data` is not possible, because Rust stores an
> index in the of device id instead of a data pointer. This was done this
> way to provide a convenient and obvious API for drivers, which can be
> evaluated in const context without the use of any unstable language
> features.
>
> Fixes: 7a718a1f26d1 ("rust: driver: implement `Adapter`")
> Signed-off-by: Markus Probst <markus.probst@posteo.de>

From the ACPI side

Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>

but I'm not a Rust expert.

> ---
> Changes in v3:
> - use acpi/acpi_bus.h instead of drivers/acpi/internal.h to declare
> `acpi_of_match_device`
> - Link to v2: https://lore.kernel.org/r/20260405-rust_acpi_prp0001-v2-1-4f8b1cf075d3@posteo.de
>
> Changes in v2:
> - keep unsafe block as short as possible
> - don't export acpi_of_match_device
> - add implementation decisions to commit msg
> - Link to v1: https://lore.kernel.org/r/20260401-rust_acpi_prp0001-v1-1-f6a4d2ef9244@posteo.de
> ---
> MAINTAINERS | 1 +
> drivers/acpi/bus.c | 6 ++--
> include/acpi/acpi_bus.h | 4 +++
> rust/bindings/bindings_helper.h | 5 +++
> rust/helpers/acpi.c | 8 +++++
> rust/helpers/helpers.c | 1 +
> rust/kernel/driver.rs | 70 ++++++++++++++++++++++++++++++++---------
> 7 files changed, 78 insertions(+), 17 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c3fe46d7c4bc..3a7b3b5f2a28 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -302,6 +302,7 @@ F: include/linux/acpi.h
> F: include/linux/fwnode.h
> F: include/linux/fw_table.h
> F: lib/fw_table.c
> +F: rust/helpers/acpi.c
> F: rust/kernel/acpi.rs
> F: tools/power/acpi/
>
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index 2ec095e2009e..554dbddb1c8c 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -831,9 +831,9 @@ const struct acpi_device *acpi_companion_match(const struct device *dev)
> * identifiers and a _DSD object with the "compatible" property, use that
> * property to match against the given list of identifiers.
> */
> -static bool acpi_of_match_device(const struct acpi_device *adev,
> - const struct of_device_id *of_match_table,
> - const struct of_device_id **of_id)
> +bool acpi_of_match_device(const struct acpi_device *adev,
> + const struct of_device_id *of_match_table,
> + const struct of_device_id **of_id)
> {
> const union acpi_object *of_compatible, *obj;
> int i, nval;
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index aad1a95e6863..d0098f24346f 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -187,6 +187,10 @@ struct acpi_driver {
> * -----------
> */
>
> +bool acpi_of_match_device(const struct acpi_device *adev,
> + const struct of_device_id *of_match_table,
> + const struct of_device_id **of_id);
> +
> /* Status (_STA) */
>
> struct acpi_device_status {
> diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
> index 083cc44aa952..e47643ce8b50 100644
> --- a/rust/bindings/bindings_helper.h
> +++ b/rust/bindings/bindings_helper.h
> @@ -96,6 +96,11 @@
> */
> #include <../../drivers/base/base.h>
>
> +/*
> + * The driver-core Rust code needs to call `acpi_of_match_device`.
> + */
> +#include <acpi/acpi_bus.h>
> +
> #if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> // Used by `#[export]` in `drivers/gpu/drm/drm_panic_qr.rs`.
> #include <drm/drm_panic.h>
> diff --git a/rust/helpers/acpi.c b/rust/helpers/acpi.c
> new file mode 100644
> index 000000000000..f2aa00ec99c2
> --- /dev/null
> +++ b/rust/helpers/acpi.c
> @@ -0,0 +1,8 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/acpi.h>
> +
> +__rust_helper struct acpi_device *rust_helper_to_acpi_device_node(struct fwnode_handle *fwnode)
> +{
> + return to_acpi_device_node(fwnode);
> +}
> diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
> index a3c42e51f00a..8ecd1580aa69 100644
> --- a/rust/helpers/helpers.c
> +++ b/rust/helpers/helpers.c
> @@ -9,6 +9,7 @@
>
> #define __rust_helper
>
> +#include "acpi.c"
> #include "atomic.c"
> #include "atomic_ext.c"
> #include "auxiliary.c"
> diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs
> index 36de8098754d..62d7d1ab776c 100644
> --- a/rust/kernel/driver.rs
> +++ b/rust/kernel/driver.rs
> @@ -96,13 +96,18 @@
>
> use crate::{
> acpi,
> - device,
> + device::{
> + self,
> + property::FwNode, //
> + },
> of,
> prelude::*,
> types::Opaque,
> ThisModule, //
> };
>
> +use core::ptr;
> +
> /// Trait describing the layout of a specific device driver.
> ///
> /// This trait describes the layout of a specific driver structure, such as `struct pci_driver` or
> @@ -278,6 +283,18 @@ fn init(
> }
> }
>
> +#[inline(never)]
> +#[allow(clippy::missing_safety_doc)]
> +#[must_use]
> +unsafe fn acpi_of_match_device(
> + adev: *const bindings::acpi_device,
> + of_match_table: *const bindings::of_device_id,
> + of_id: *mut *const bindings::of_device_id,
> +) -> bool {
> + // SAFETY: Safety requirements are the same as `bindings::acpi_device_id`.
> + unsafe { bindings::acpi_of_match_device(adev, of_match_table, of_id) }
> +}
> +
> /// The bus independent adapter to match a drivers and a devices.
> ///
> /// This trait should be implemented by the bus specific adapter, which represents the connection
> @@ -329,35 +346,60 @@ fn acpi_id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> {
> ///
> /// If this returns `None`, it means there is no match with an entry in the [`of::IdTable`].
> fn of_id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> {
> - #[cfg(not(CONFIG_OF))]
> + let table = Self::of_id_table()?;
> +
> + #[cfg(not(any(CONFIG_OF, CONFIG_ACPI)))]
> {
> - let _ = dev;
> - None
> + let _ = (dev, table);
> }
>
> #[cfg(CONFIG_OF)]
> {
> - let table = Self::of_id_table()?;
> -
> // SAFETY:
> // - `table` has static lifetime, hence it's valid for read,
> // - `dev` is guaranteed to be valid while it's alive, and so is `dev.as_raw()`.
> let raw_id = unsafe { bindings::of_match_device(table.as_ptr(), dev.as_raw()) };
>
> - if raw_id.is_null() {
> - None
> - } else {
> + if !raw_id.is_null() {
> // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct of_device_id`
> // and does not add additional invariants, so it's safe to transmute.
> let id = unsafe { &*raw_id.cast::<of::DeviceId>() };
>
> - Some(
> - table.info(<of::DeviceId as crate::device_id::RawDeviceIdIndex>::index(
> - id,
> - )),
> - )
> + return Some(table.info(
> + <of::DeviceId as crate::device_id::RawDeviceIdIndex>::index(id),
> + ));
> }
> }
> +
> + #[cfg(CONFIG_ACPI)]
> + {
> + let mut raw_id = ptr::null();
> +
> + let fwnode = dev.fwnode().map_or(ptr::null_mut(), FwNode::as_raw);
> +
> + // SAFETY: `fwnode` is a pointer to a valid `fwnode_handle`. A null pointer will be
> + // passed through the function.
> + let adev = unsafe { bindings::to_acpi_device_node(fwnode) };
> +
> + // SAFETY:
> + // - `adev` is a valid pointer to `acpi_device` or is null. It is guaranteed to be
> + // valid as long as `dev` is alive.
> + // - `table` has static lifetime, hence it's valid for read.
> + if unsafe { acpi_of_match_device(adev, table.as_ptr(), &raw mut raw_id) } {
> + // SAFETY:
> + // - the function returns true, therefore `raw_id` has been set to a pointer to a
> + // valid `of_device_id`.
> + // - `DeviceId` is a `#[repr(transparent)]` wrapper of `struct of_device_id`
> + // and does not add additional invariants, so it's safe to transmute.
> + let id = unsafe { &*raw_id.cast::<of::DeviceId>() };
> +
> + return Some(table.info(
> + <of::DeviceId as crate::device_id::RawDeviceIdIndex>::index(id),
> + ));
> + }
> + }
> +
> + None
> }
>
> /// Returns the driver's private data from the matching entry of any of the ID tables, if any.
>
> ---
> base-commit: 0e5d0a0b5ca6ea4e391d6786266405c5871e0151
> change-id: 20260401-rust_acpi_prp0001-a2971543b555
>
>