diff options
Diffstat (limited to 'rust/kernel')
| -rw-r--r-- | rust/kernel/acpi.rs | 15 | ||||
| -rw-r--r-- | rust/kernel/auxiliary.rs | 11 | ||||
| -rw-r--r-- | rust/kernel/device_id.rs | 91 | ||||
| -rw-r--r-- | rust/kernel/driver.rs | 8 | ||||
| -rw-r--r-- | rust/kernel/of.rs | 15 | ||||
| -rw-r--r-- | rust/kernel/pci.rs | 11 |
6 files changed, 104 insertions, 47 deletions
diff --git a/rust/kernel/acpi.rs b/rust/kernel/acpi.rs index 2af4d4f92924..7ae317368b00 100644 --- a/rust/kernel/acpi.rs +++ b/rust/kernel/acpi.rs @@ -2,7 +2,11 @@ //! Advanced Configuration and Power Interface abstractions. -use crate::{bindings, device_id::RawDeviceId, prelude::*}; +use crate::{ + bindings, + device_id::{RawDeviceId, RawDeviceIdIndex}, + prelude::*, +}; /// IdTable type for ACPI drivers. pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; @@ -12,13 +16,14 @@ pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; #[derive(Clone, Copy)] pub struct DeviceId(bindings::acpi_device_id); -// SAFETY: -// * `DeviceId` is a `#[repr(transparent)` wrapper of `struct acpi_device_id` and does not add -// additional invariants, so it's safe to transmute to `RawType`. -// * `DRIVER_DATA_OFFSET` is the offset to the `data` field. +// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `acpi_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. unsafe impl RawDeviceId for DeviceId { type RawType = bindings::acpi_device_id; +} +// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceIdIndex for DeviceId { const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::acpi_device_id, driver_data); fn index(&self) -> usize { diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs index e1f2a2e6b607..4749fb6bffef 100644 --- a/rust/kernel/auxiliary.rs +++ b/rust/kernel/auxiliary.rs @@ -6,7 +6,7 @@ use crate::{ bindings, container_of, device, - device_id::RawDeviceId, + device_id::{RawDeviceId, RawDeviceIdIndex}, driver, error::{from_result, to_result, Result}, prelude::*, @@ -134,13 +134,14 @@ impl DeviceId { } } -// SAFETY: -// * `DeviceId` is a `#[repr(transparent)`] wrapper of `auxiliary_device_id` and does not add -// additional invariants, so it's safe to transmute to `RawType`. -// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `auxiliary_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. unsafe impl RawDeviceId for DeviceId { type RawType = bindings::auxiliary_device_id; +} +// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceIdIndex for DeviceId { const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::auxiliary_device_id, driver_data); diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs index 0a4eb56d98f2..8ed2c946144c 100644 --- a/rust/kernel/device_id.rs +++ b/rust/kernel/device_id.rs @@ -14,32 +14,41 @@ use core::mem::MaybeUninit; /// /// # Safety /// -/// Implementers must ensure that: -/// - `Self` is layout-compatible with [`RawDeviceId::RawType`]; i.e. it's safe to transmute to -/// `RawDeviceId`. +/// Implementers must ensure that `Self` is layout-compatible with [`RawDeviceId::RawType`]; +/// i.e. it's safe to transmute to `RawDeviceId`. /// -/// This requirement is needed so `IdArray::new` can convert `Self` to `RawType` when building -/// the ID table. +/// This requirement is needed so `IdArray::new` can convert `Self` to `RawType` when building +/// the ID table. /// -/// Ideally, this should be achieved using a const function that does conversion instead of -/// transmute; however, const trait functions relies on `const_trait_impl` unstable feature, -/// which is broken/gone in Rust 1.73. -/// -/// - `DRIVER_DATA_OFFSET` is the offset of context/data field of the device ID (usually named -/// `driver_data`) of the device ID, the field is suitable sized to write a `usize` value. -/// -/// Similar to the previous requirement, the data should ideally be added during `Self` to -/// `RawType` conversion, but there's currently no way to do it when using traits in const. +/// Ideally, this should be achieved using a const function that does conversion instead of +/// transmute; however, const trait functions relies on `const_trait_impl` unstable feature, +/// which is broken/gone in Rust 1.73. pub unsafe trait RawDeviceId { /// The raw type that holds the device id. /// /// Id tables created from [`Self`] are going to hold this type in its zero-terminated array. type RawType: Copy; +} - /// The offset to the context/data field. +/// Extension trait for [`RawDeviceId`] for devices that embed an index or context value. +/// +/// This is typically used when the device ID struct includes a field like `driver_data` +/// that is used to store a pointer-sized value (e.g., an index or context pointer). +/// +/// # Safety +/// +/// Implementers must ensure that `DRIVER_DATA_OFFSET` is the correct offset (in bytes) to +/// the context/data field (e.g., the `driver_data` field) within the raw device ID structure. +/// This field must be correctly sized to hold a `usize`. +/// +/// Ideally, the data should be added during `Self` to `RawType` conversion, +/// but there's currently no way to do it when using traits in const. +pub unsafe trait RawDeviceIdIndex: RawDeviceId { + /// The offset (in bytes) to the context/data field in the raw device ID. const DRIVER_DATA_OFFSET: usize; - /// The index stored at `DRIVER_DATA_OFFSET` of the implementor of the [`RawDeviceId`] trait. + /// The index stored at `DRIVER_DATA_OFFSET` of the implementor of the [`RawDeviceIdIndex`] + /// trait. fn index(&self) -> usize; } @@ -68,7 +77,15 @@ impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> { /// Creates a new instance of the array. /// /// The contents are derived from the given identifiers and context information. - pub const fn new(ids: [(T, U); N]) -> Self { + /// + /// # Safety + /// + /// `data_offset` as `None` is always safe. + /// If `data_offset` is `Some(data_offset)`, then: + /// - `data_offset` must be the correct offset (in bytes) to the context/data field + /// (e.g., the `driver_data` field) within the raw device ID structure. + /// - The field at `data_offset` must be correctly sized to hold a `usize`. + const unsafe fn build(ids: [(T, U); N], data_offset: Option<usize>) -> Self { let mut raw_ids = [const { MaybeUninit::<T::RawType>::uninit() }; N]; let mut infos = [const { MaybeUninit::uninit() }; N]; @@ -77,14 +94,16 @@ impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> { // SAFETY: by the safety requirement of `RawDeviceId`, we're guaranteed that `T` is // layout-wise compatible with `RawType`. raw_ids[i] = unsafe { core::mem::transmute_copy(&ids[i].0) }; - // SAFETY: by the safety requirement of `RawDeviceId`, this would be effectively - // `raw_ids[i].driver_data = i;`. - unsafe { - raw_ids[i] - .as_mut_ptr() - .byte_offset(T::DRIVER_DATA_OFFSET as _) - .cast::<usize>() - .write(i); + if let Some(data_offset) = data_offset { + // SAFETY: by the safety requirement of this function, this would be effectively + // `raw_ids[i].driver_data = i;`. + unsafe { + raw_ids[i] + .as_mut_ptr() + .byte_offset(data_offset as _) + .cast::<usize>() + .write(i); + } } // SAFETY: this is effectively a move: `infos[i] = ids[i].1`. We make a copy here but @@ -109,12 +128,34 @@ impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> { } } + /// Creates a new instance of the array without writing index values. + /// + /// The contents are derived from the given identifiers and context information. + /// If the device implements [`RawDeviceIdIndex`], consider using [`IdArray::new`] instead. + pub const fn new_without_index(ids: [(T, U); N]) -> Self { + // SAFETY: Calling `Self::build` with `offset = None` is always safe, + // because no raw memory writes are performed in this case. + unsafe { Self::build(ids, None) } + } + /// Reference to the contained [`RawIdArray`]. pub const fn raw_ids(&self) -> &RawIdArray<T, N> { &self.raw_ids } } +impl<T: RawDeviceId + RawDeviceIdIndex, U, const N: usize> IdArray<T, U, N> { + /// Creates a new instance of the array. + /// + /// The contents are derived from the given identifiers and context information. + pub const fn new(ids: [(T, U); N]) -> Self { + // SAFETY: by the safety requirement of `RawDeviceIdIndex`, + // `T::DRIVER_DATA_OFFSET` is guaranteed to be the correct offset (in bytes) to + // a field within `T::RawType`. + unsafe { Self::build(ids, Some(T::DRIVER_DATA_OFFSET)) } + } +} + /// A device id table. /// /// This trait is only implemented by `IdArray`. diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs index f8dd7593e8dc..a8f2675ba7a7 100644 --- a/rust/kernel/driver.rs +++ b/rust/kernel/driver.rs @@ -170,7 +170,7 @@ pub trait Adapter { // and does not add additional invariants, so it's safe to transmute. let id = unsafe { &*raw_id.cast::<acpi::DeviceId>() }; - Some(table.info(<acpi::DeviceId as crate::device_id::RawDeviceId>::index(id))) + Some(table.info(<acpi::DeviceId as crate::device_id::RawDeviceIdIndex>::index(id))) } } } @@ -204,7 +204,11 @@ pub trait Adapter { // 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::RawDeviceId>::index(id))) + Some( + table.info(<of::DeviceId as crate::device_id::RawDeviceIdIndex>::index( + id, + )), + ) } } } diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs index 52fe0c77b9a1..0888469bddb7 100644 --- a/rust/kernel/of.rs +++ b/rust/kernel/of.rs @@ -2,7 +2,11 @@ //! Device Tree / Open Firmware abstractions. -use crate::{bindings, device_id::RawDeviceId, prelude::*}; +use crate::{ + bindings, + device_id::{RawDeviceId, RawDeviceIdIndex}, + prelude::*, +}; /// IdTable type for OF drivers. pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; @@ -12,13 +16,14 @@ pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; #[derive(Clone, Copy)] pub struct DeviceId(bindings::of_device_id); -// SAFETY: -// * `DeviceId` is a `#[repr(transparent)]` wrapper of `struct of_device_id` and does not add -// additional invariants, so it's safe to transmute to `RawType`. -// * `DRIVER_DATA_OFFSET` is the offset to the `data` field. +// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct of_device_id` and +// does not add additional invariants, so it's safe to transmute to `RawType`. unsafe impl RawDeviceId for DeviceId { type RawType = bindings::of_device_id; +} +// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `data` field. +unsafe impl RawDeviceIdIndex for DeviceId { const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::of_device_id, data); fn index(&self) -> usize { diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index c9f7cb04d2e5..6a4854cf4bf9 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -6,7 +6,7 @@ use crate::{ bindings, container_of, device, - device_id::RawDeviceId, + device_id::{RawDeviceId, RawDeviceIdIndex}, devres::Devres, driver, error::{from_result, to_result, Result}, @@ -159,13 +159,14 @@ impl DeviceId { } } -// SAFETY: -// * `DeviceId` is a `#[repr(transparent)]` wrapper of `pci_device_id` and does not add -// additional invariants, so it's safe to transmute to `RawType`. -// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `pci_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. unsafe impl RawDeviceId for DeviceId { type RawType = bindings::pci_device_id; +} +// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceIdIndex for DeviceId { const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data); fn index(&self) -> usize { |