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-rw-r--r--rust/kernel/alloc/kbox.rs41
-rw-r--r--rust/kernel/miscdevice.rs10
-rw-r--r--rust/kernel/pci.rs2
-rw-r--r--rust/kernel/platform.rs2
-rw-r--r--rust/kernel/sync/arc.rs24
-rw-r--r--rust/kernel/types.rs45
-rw-r--r--rust/kernel/xarray.rs9
7 files changed, 70 insertions, 63 deletions
diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs
index c386ff771d50..bffe72f44cb3 100644
--- a/rust/kernel/alloc/kbox.rs
+++ b/rust/kernel/alloc/kbox.rs
@@ -15,6 +15,7 @@ use core::pin::Pin;
use core::ptr::NonNull;
use core::result::Result;
+use crate::ffi::c_void;
use crate::init::InPlaceInit;
use crate::types::ForeignOwnable;
use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption};
@@ -398,70 +399,74 @@ where
}
}
-// SAFETY: The `into_foreign` function returns a pointer that is well-aligned.
+// SAFETY: The pointer returned by `into_foreign` comes from a well aligned
+// pointer to `T`.
unsafe impl<T: 'static, A> ForeignOwnable for Box<T, A>
where
A: Allocator,
{
- type PointedTo = T;
+ const FOREIGN_ALIGN: usize = core::mem::align_of::<T>();
type Borrowed<'a> = &'a T;
type BorrowedMut<'a> = &'a mut T;
- fn into_foreign(self) -> *mut Self::PointedTo {
- Box::into_raw(self)
+ fn into_foreign(self) -> *mut c_void {
+ Box::into_raw(self).cast()
}
- unsafe fn from_foreign(ptr: *mut Self::PointedTo) -> Self {
+ unsafe fn from_foreign(ptr: *mut c_void) -> Self {
// SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
// call to `Self::into_foreign`.
- unsafe { Box::from_raw(ptr) }
+ unsafe { Box::from_raw(ptr.cast()) }
}
- unsafe fn borrow<'a>(ptr: *mut Self::PointedTo) -> &'a T {
+ unsafe fn borrow<'a>(ptr: *mut c_void) -> &'a T {
// SAFETY: The safety requirements of this method ensure that the object remains alive and
// immutable for the duration of 'a.
- unsafe { &*ptr }
+ unsafe { &*ptr.cast() }
}
- unsafe fn borrow_mut<'a>(ptr: *mut Self::PointedTo) -> &'a mut T {
+ unsafe fn borrow_mut<'a>(ptr: *mut c_void) -> &'a mut T {
+ let ptr = ptr.cast();
// SAFETY: The safety requirements of this method ensure that the pointer is valid and that
// nothing else will access the value for the duration of 'a.
unsafe { &mut *ptr }
}
}
-// SAFETY: The `into_foreign` function returns a pointer that is well-aligned.
+// SAFETY: The pointer returned by `into_foreign` comes from a well aligned
+// pointer to `T`.
unsafe impl<T: 'static, A> ForeignOwnable for Pin<Box<T, A>>
where
A: Allocator,
{
- type PointedTo = T;
+ const FOREIGN_ALIGN: usize = core::mem::align_of::<T>();
type Borrowed<'a> = Pin<&'a T>;
type BorrowedMut<'a> = Pin<&'a mut T>;
- fn into_foreign(self) -> *mut Self::PointedTo {
+ fn into_foreign(self) -> *mut c_void {
// SAFETY: We are still treating the box as pinned.
- Box::into_raw(unsafe { Pin::into_inner_unchecked(self) })
+ Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }).cast()
}
- unsafe fn from_foreign(ptr: *mut Self::PointedTo) -> Self {
+ unsafe fn from_foreign(ptr: *mut c_void) -> Self {
// SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
// call to `Self::into_foreign`.
- unsafe { Pin::new_unchecked(Box::from_raw(ptr)) }
+ unsafe { Pin::new_unchecked(Box::from_raw(ptr.cast())) }
}
- unsafe fn borrow<'a>(ptr: *mut Self::PointedTo) -> Pin<&'a T> {
+ unsafe fn borrow<'a>(ptr: *mut c_void) -> Pin<&'a T> {
// SAFETY: The safety requirements for this function ensure that the object is still alive,
// so it is safe to dereference the raw pointer.
// The safety requirements of `from_foreign` also ensure that the object remains alive for
// the lifetime of the returned value.
- let r = unsafe { &*ptr };
+ let r = unsafe { &*ptr.cast() };
// SAFETY: This pointer originates from a `Pin<Box<T>>`.
unsafe { Pin::new_unchecked(r) }
}
- unsafe fn borrow_mut<'a>(ptr: *mut Self::PointedTo) -> Pin<&'a mut T> {
+ unsafe fn borrow_mut<'a>(ptr: *mut c_void) -> Pin<&'a mut T> {
+ let ptr = ptr.cast();
// SAFETY: The safety requirements for this function ensure that the object is still alive,
// so it is safe to dereference the raw pointer.
// The safety requirements of `from_foreign` also ensure that the object remains alive for
diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs
index 288f40e79906..ad51ffc549b8 100644
--- a/rust/kernel/miscdevice.rs
+++ b/rust/kernel/miscdevice.rs
@@ -217,7 +217,7 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
// type.
//
// SAFETY: The open call of a file can access the private data.
- unsafe { (*raw_file).private_data = ptr.into_foreign().cast() };
+ unsafe { (*raw_file).private_data = ptr.into_foreign() };
0
}
@@ -228,7 +228,7 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
/// must be associated with a `MiscDeviceRegistration<T>`.
unsafe extern "C" fn release(_inode: *mut bindings::inode, file: *mut bindings::file) -> c_int {
// SAFETY: The release call of a file owns the private data.
- let private = unsafe { (*file).private_data }.cast();
+ let private = unsafe { (*file).private_data };
// SAFETY: The release call of a file owns the private data.
let ptr = unsafe { <T::Ptr as ForeignOwnable>::from_foreign(private) };
@@ -272,7 +272,7 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
/// `file` must be a valid file that is associated with a `MiscDeviceRegistration<T>`.
unsafe extern "C" fn ioctl(file: *mut bindings::file, cmd: c_uint, arg: c_ulong) -> c_long {
// SAFETY: The ioctl call of a file can access the private data.
- let private = unsafe { (*file).private_data }.cast();
+ let private = unsafe { (*file).private_data };
// SAFETY: Ioctl calls can borrow the private data of the file.
let device = unsafe { <T::Ptr as ForeignOwnable>::borrow(private) };
@@ -297,7 +297,7 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
arg: c_ulong,
) -> c_long {
// SAFETY: The compat ioctl call of a file can access the private data.
- let private = unsafe { (*file).private_data }.cast();
+ let private = unsafe { (*file).private_data };
// SAFETY: Ioctl calls can borrow the private data of the file.
let device = unsafe { <T::Ptr as ForeignOwnable>::borrow(private) };
@@ -318,7 +318,7 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
/// - `seq_file` must be a valid `struct seq_file` that we can write to.
unsafe extern "C" fn show_fdinfo(seq_file: *mut bindings::seq_file, file: *mut bindings::file) {
// SAFETY: The release call of a file owns the private data.
- let private = unsafe { (*file).private_data }.cast();
+ let private = unsafe { (*file).private_data };
// SAFETY: Ioctl calls can borrow the private data of the file.
let device = unsafe { <T::Ptr as ForeignOwnable>::borrow(private) };
// SAFETY:
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 6b94fd7a3ce9..5ce07999168e 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -89,7 +89,7 @@ impl<T: Driver + 'static> Adapter<T> {
extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) {
// SAFETY: The PCI bus only ever calls the remove callback with a valid pointer to a
// `struct pci_dev`.
- let ptr = unsafe { bindings::pci_get_drvdata(pdev) }.cast();
+ let ptr = unsafe { bindings::pci_get_drvdata(pdev) };
// SAFETY: `remove_callback` is only ever called after a successful call to
// `probe_callback`, hence it's guaranteed that `ptr` points to a valid and initialized
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 0a6a6be732b2..e894790c510c 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -81,7 +81,7 @@ impl<T: Driver + 'static> Adapter<T> {
extern "C" fn remove_callback(pdev: *mut bindings::platform_device) {
// SAFETY: `pdev` is a valid pointer to a `struct platform_device`.
- let ptr = unsafe { bindings::platform_get_drvdata(pdev) }.cast();
+ let ptr = unsafe { bindings::platform_get_drvdata(pdev) };
// SAFETY: `remove_callback` is only ever called after a successful call to
// `probe_callback`, hence it's guaranteed that `ptr` points to a valid and initialized
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index 499175f637a7..63a66761d0c7 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -19,6 +19,7 @@
use crate::{
alloc::{AllocError, Flags, KBox},
bindings,
+ ffi::c_void,
init::InPlaceInit,
try_init,
types::{ForeignOwnable, Opaque},
@@ -141,10 +142,9 @@ pub struct Arc<T: ?Sized> {
_p: PhantomData<ArcInner<T>>,
}
-#[doc(hidden)]
#[pin_data]
#[repr(C)]
-pub struct ArcInner<T: ?Sized> {
+struct ArcInner<T: ?Sized> {
refcount: Opaque<bindings::refcount_t>,
data: T,
}
@@ -373,20 +373,22 @@ impl<T: ?Sized> Arc<T> {
}
}
-// SAFETY: The `into_foreign` function returns a pointer that is well-aligned.
+// SAFETY: The pointer returned by `into_foreign` comes from a well aligned
+// pointer to `ArcInner<T>`.
unsafe impl<T: 'static> ForeignOwnable for Arc<T> {
- type PointedTo = ArcInner<T>;
+ const FOREIGN_ALIGN: usize = core::mem::align_of::<ArcInner<T>>();
+
type Borrowed<'a> = ArcBorrow<'a, T>;
type BorrowedMut<'a> = Self::Borrowed<'a>;
- fn into_foreign(self) -> *mut Self::PointedTo {
- ManuallyDrop::new(self).ptr.as_ptr()
+ fn into_foreign(self) -> *mut c_void {
+ ManuallyDrop::new(self).ptr.as_ptr().cast()
}
- unsafe fn from_foreign(ptr: *mut Self::PointedTo) -> Self {
+ unsafe fn from_foreign(ptr: *mut c_void) -> Self {
// SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
// call to `Self::into_foreign`.
- let inner = unsafe { NonNull::new_unchecked(ptr) };
+ let inner = unsafe { NonNull::new_unchecked(ptr.cast::<ArcInner<T>>()) };
// SAFETY: By the safety requirement of this function, we know that `ptr` came from
// a previous call to `Arc::into_foreign`, which guarantees that `ptr` is valid and
@@ -394,17 +396,17 @@ unsafe impl<T: 'static> ForeignOwnable for Arc<T> {
unsafe { Self::from_inner(inner) }
}
- unsafe fn borrow<'a>(ptr: *mut Self::PointedTo) -> ArcBorrow<'a, T> {
+ unsafe fn borrow<'a>(ptr: *mut c_void) -> ArcBorrow<'a, T> {
// SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
// call to `Self::into_foreign`.
- let inner = unsafe { NonNull::new_unchecked(ptr) };
+ let inner = unsafe { NonNull::new_unchecked(ptr.cast::<ArcInner<T>>()) };
// SAFETY: The safety requirements of `from_foreign` ensure that the object remains alive
// for the lifetime of the returned value.
unsafe { ArcBorrow::new(inner) }
}
- unsafe fn borrow_mut<'a>(ptr: *mut Self::PointedTo) -> ArcBorrow<'a, T> {
+ unsafe fn borrow_mut<'a>(ptr: *mut c_void) -> ArcBorrow<'a, T> {
// SAFETY: The safety requirements for `borrow_mut` are a superset of the safety
// requirements for `borrow`.
unsafe { <Self as ForeignOwnable>::borrow(ptr) }
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index 22985b6f6982..c156808a78d3 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -2,6 +2,7 @@
//! Kernel types.
+use crate::ffi::c_void;
use core::{
cell::UnsafeCell,
marker::{PhantomData, PhantomPinned},
@@ -21,15 +22,10 @@ use pin_init::{PinInit, Zeroable};
///
/// # Safety
///
-/// Implementers must ensure that [`into_foreign`] returns a pointer which meets the alignment
-/// requirements of [`PointedTo`].
-///
-/// [`into_foreign`]: Self::into_foreign
-/// [`PointedTo`]: Self::PointedTo
+/// - Implementations must satisfy the guarantees of [`Self::into_foreign`].
pub unsafe trait ForeignOwnable: Sized {
- /// Type used when the value is foreign-owned. In practical terms only defines the alignment of
- /// the pointer.
- type PointedTo;
+ /// The alignment of pointers returned by `into_foreign`.
+ const FOREIGN_ALIGN: usize;
/// Type used to immutably borrow a value that is currently foreign-owned.
type Borrowed<'a>;
@@ -39,18 +35,20 @@ pub unsafe trait ForeignOwnable: Sized {
/// Converts a Rust-owned object to a foreign-owned one.
///
+ /// The foreign representation is a pointer to void. Aside from the guarantees listed below,
+ /// there are no other guarantees for this pointer. For example, it might be invalid, dangling
+ /// or pointing to uninitialized memory. Using it in any way except for [`from_foreign`],
+ /// [`try_from_foreign`], [`borrow`], or [`borrow_mut`] can result in undefined behavior.
+ ///
/// # Guarantees
///
- /// The return value is guaranteed to be well-aligned, but there are no other guarantees for
- /// this pointer. For example, it might be null, dangling, or point to uninitialized memory.
- /// Using it in any way except for [`ForeignOwnable::from_foreign`], [`ForeignOwnable::borrow`],
- /// [`ForeignOwnable::try_from_foreign`] can result in undefined behavior.
+ /// - Minimum alignment of returned pointer is [`Self::FOREIGN_ALIGN`].
///
/// [`from_foreign`]: Self::from_foreign
/// [`try_from_foreign`]: Self::try_from_foreign
/// [`borrow`]: Self::borrow
/// [`borrow_mut`]: Self::borrow_mut
- fn into_foreign(self) -> *mut Self::PointedTo;
+ fn into_foreign(self) -> *mut c_void;
/// Converts a foreign-owned object back to a Rust-owned one.
///
@@ -60,7 +58,7 @@ pub unsafe trait ForeignOwnable: Sized {
/// must not be passed to `from_foreign` more than once.
///
/// [`into_foreign`]: Self::into_foreign
- unsafe fn from_foreign(ptr: *mut Self::PointedTo) -> Self;
+ unsafe fn from_foreign(ptr: *mut c_void) -> Self;
/// Tries to convert a foreign-owned object back to a Rust-owned one.
///
@@ -72,7 +70,7 @@ pub unsafe trait ForeignOwnable: Sized {
/// `ptr` must either be null or satisfy the safety requirements for [`from_foreign`].
///
/// [`from_foreign`]: Self::from_foreign
- unsafe fn try_from_foreign(ptr: *mut Self::PointedTo) -> Option<Self> {
+ unsafe fn try_from_foreign(ptr: *mut c_void) -> Option<Self> {
if ptr.is_null() {
None
} else {
@@ -95,7 +93,7 @@ pub unsafe trait ForeignOwnable: Sized {
///
/// [`into_foreign`]: Self::into_foreign
/// [`from_foreign`]: Self::from_foreign
- unsafe fn borrow<'a>(ptr: *mut Self::PointedTo) -> Self::Borrowed<'a>;
+ unsafe fn borrow<'a>(ptr: *mut c_void) -> Self::Borrowed<'a>;
/// Borrows a foreign-owned object mutably.
///
@@ -123,23 +121,24 @@ pub unsafe trait ForeignOwnable: Sized {
/// [`from_foreign`]: Self::from_foreign
/// [`borrow`]: Self::borrow
/// [`Arc`]: crate::sync::Arc
- unsafe fn borrow_mut<'a>(ptr: *mut Self::PointedTo) -> Self::BorrowedMut<'a>;
+ unsafe fn borrow_mut<'a>(ptr: *mut c_void) -> Self::BorrowedMut<'a>;
}
-// SAFETY: The `into_foreign` function returns a pointer that is dangling, but well-aligned.
+// SAFETY: The pointer returned by `into_foreign` comes from a well aligned
+// pointer to `()`.
unsafe impl ForeignOwnable for () {
- type PointedTo = ();
+ const FOREIGN_ALIGN: usize = core::mem::align_of::<()>();
type Borrowed<'a> = ();
type BorrowedMut<'a> = ();
- fn into_foreign(self) -> *mut Self::PointedTo {
+ fn into_foreign(self) -> *mut c_void {
core::ptr::NonNull::dangling().as_ptr()
}
- unsafe fn from_foreign(_: *mut Self::PointedTo) -> Self {}
+ unsafe fn from_foreign(_: *mut c_void) -> Self {}
- unsafe fn borrow<'a>(_: *mut Self::PointedTo) -> Self::Borrowed<'a> {}
- unsafe fn borrow_mut<'a>(_: *mut Self::PointedTo) -> Self::BorrowedMut<'a> {}
+ unsafe fn borrow<'a>(_: *mut c_void) -> Self::Borrowed<'a> {}
+ unsafe fn borrow_mut<'a>(_: *mut c_void) -> Self::BorrowedMut<'a> {}
}
/// Runs a cleanup function/closure when dropped.
diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
index 75719e7bb491..a49d6db28845 100644
--- a/rust/kernel/xarray.rs
+++ b/rust/kernel/xarray.rs
@@ -7,9 +7,10 @@
use crate::{
alloc, bindings, build_assert,
error::{Error, Result},
+ ffi::c_void,
types::{ForeignOwnable, NotThreadSafe, Opaque},
};
-use core::{iter, marker::PhantomData, mem, pin::Pin, ptr::NonNull};
+use core::{iter, marker::PhantomData, pin::Pin, ptr::NonNull};
use pin_init::{pin_data, pin_init, pinned_drop, PinInit};
/// An array which efficiently maps sparse integer indices to owned objects.
@@ -101,7 +102,7 @@ impl<T: ForeignOwnable> XArray<T> {
})
}
- fn iter(&self) -> impl Iterator<Item = NonNull<T::PointedTo>> + '_ {
+ fn iter(&self) -> impl Iterator<Item = NonNull<c_void>> + '_ {
let mut index = 0;
// SAFETY: `self.xa` is always valid by the type invariant.
@@ -179,7 +180,7 @@ impl<T> From<StoreError<T>> for Error {
impl<'a, T: ForeignOwnable> Guard<'a, T> {
fn load<F, U>(&self, index: usize, f: F) -> Option<U>
where
- F: FnOnce(NonNull<T::PointedTo>) -> U,
+ F: FnOnce(NonNull<c_void>) -> U,
{
// SAFETY: `self.xa.xa` is always valid by the type invariant.
let ptr = unsafe { bindings::xa_load(self.xa.xa.get(), index) };
@@ -230,7 +231,7 @@ impl<'a, T: ForeignOwnable> Guard<'a, T> {
gfp: alloc::Flags,
) -> Result<Option<T>, StoreError<T>> {
build_assert!(
- mem::align_of::<T::PointedTo>() >= 4,
+ T::FOREIGN_ALIGN >= 4,
"pointers stored in XArray must be 4-byte aligned"
);
let new = value.into_foreign();
generated by cgit (git 2.34.1) at 2025-08-31 07:56:54 +0000