Merge tag 'drm-rust-fixes-2026-03-12' of https://gitlab.freedesktop.org/drm/rust/kernel into drm-fixes

Core Changes:

- Fix safety issue in dma_read! and dma_write!.

Driver Changes (Nova Core):

- Fix UB in DmaGspMem pointer accessors.
- Fix stack overflow in GSP memory allocation.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/abNBSol3CLRCqlkZ@google.com

1 files changed, 29 insertions, 1 deletions

diff --git a/rust/kernel/ptr.rs b/rust/kernel/ptr.rs
index 5b6a382637fe..bdc2d79ff669 100644
--- a/rust/kernel/ptr.rs
+++ b/rust/kernel/ptr.rs
@@ -2,7 +2,13 @@
 
 //! Types and functions to work with pointers and addresses.
 
-use core::mem::align_of;
+pub mod projection;
+pub use crate::project_pointer as project;
+
+use core::mem::{
+    align_of,
+    size_of, //
+};
 use core::num::NonZero;
 
 /// Type representing an alignment, which is always a power of two.
@@ -225,3 +231,25 @@ macro_rules! impl_alignable_uint {
 }
 
 impl_alignable_uint!(u8, u16, u32, u64, usize);
+
+/// Trait to represent compile-time known size information.
+///
+/// This is a generalization of [`size_of`] that works for dynamically sized types.
+pub trait KnownSize {
+    /// Get the size of an object of this type in bytes, with the metadata of the given pointer.
+    fn size(p: *const Self) -> usize;
+}
+
+impl<T> KnownSize for T {
+    #[inline(always)]
+    fn size(_: *const Self) -> usize {
+        size_of::<T>()
+    }
+}
+
+impl<T> KnownSize for [T] {
+    #[inline(always)]
+    fn size(p: *const Self) -> usize {
+        p.len() * size_of::<T>()
+    }
+}