1 files changed, 60 insertions, 4 deletions

diff --git a/rust/kernel/ptr.rs b/rust/kernel/ptr.rs
index e3893ed04049..3f3e529e9f58 100644
--- a/rust/kernel/ptr.rs
+++ b/rust/kernel/ptr.rs
@@ -2,10 +2,16 @@
 
 //! 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;
 
-use crate::build_assert;
+use crate::const_assert;
 
 /// Type representing an alignment, which is always a power of two.
 ///
@@ -40,7 +46,7 @@ impl Alignment {
     /// ```
     #[inline(always)]
     pub const fn new<const ALIGN: usize>() -> Self {
-        build_assert!(
+        const_assert!(
             ALIGN.is_power_of_two(),
             "Provided alignment is not a power of two."
         );
@@ -81,7 +87,6 @@ impl Alignment {
     /// This is equivalent to [`align_of`], but with the return value provided as an [`Alignment`].
     #[inline(always)]
     pub const fn of<T>() -> Self {
-        #![allow(clippy::incompatible_msrv)]
         // This cannot panic since alignments are always powers of two.
         //
         // We unfortunately cannot use `new` as it would require the `generic_const_exprs` feature.
@@ -225,3 +230,54 @@ 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>()
+    }
+}
+
+/// Aligns `value` up to `align`.
+///
+/// This is the const-compatible equivalent of [`Alignable::align_up`].
+///
+/// Returns [`None`] on overflow.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::{
+///     ptr::{
+///         const_align_up,
+///         Alignment, //
+///     },
+///     sizes::SZ_4K, //
+/// };
+///
+/// assert_eq!(const_align_up(0x4f, Alignment::new::<16>()), Some(0x50));
+/// assert_eq!(const_align_up(0x40, Alignment::new::<16>()), Some(0x40));
+/// assert_eq!(const_align_up(1, Alignment::new::<SZ_4K>()), Some(SZ_4K));
+/// ```
+#[inline(always)]
+pub const fn const_align_up(value: usize, align: Alignment) -> Option<usize> {
+    match value.checked_add(align.as_usize() - 1) {
+        Some(v) => Some(v & align.mask()),
+        None => None,
+    }
+}