Merge tag 'rust-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Derive 'Zeroable' for all structs and unions generated by 'bindgen'
     where possible and corresponding cleanups. To do so, add the
     'pin-init' crate as a dependency to 'bindings' and 'uapi'.

     It also includes its first use in the 'cpufreq' module, with more
     to come in the next cycle.

   - Add warning to the 'rustdoc' target to detect broken 'srctree/'
     links and fix existing cases.

   - Remove support for unused (since v6.16) host '#[test]'s,
     simplifying the 'rusttest' target. Tests should generally run
     within KUnit.

  'kernel' crate:

   - Add 'ptr' module with a new 'Alignment' type, which is always a
     power of two and is used to validate that a given value is a valid
     alignment and to perform masking and alignment operations:

         // Checked at build time.
         assert_eq!(Alignment::new::<16>().as_usize(), 16);

         // Checked at runtime.
         assert_eq!(Alignment::new_checked(15), None);

         assert_eq!(Alignment::of::<u8>().log2(), 0);

         assert_eq!(0x25u8.align_down(Alignment::new::<0x10>()), 0x20);
         assert_eq!(0x5u8.align_up(Alignment::new::<0x10>()), Some(0x10));
         assert_eq!(u8::MAX.align_up(Alignment::new::<0x10>()), None);

     It also includes its first use in Nova.

   - Add 'core::mem::{align,size}_of{,_val}' to the prelude, matching
     Rust 1.80.0.

   - Keep going with the steps on our migration to the standard library
     'core::ffi::CStr' type (use 'kernel::{fmt, prelude::fmt!}' and use
     upstream method names).

   - 'error' module: improve 'Error::from_errno' and 'to_result'
     documentation, including examples/tests.

   - 'sync' module: extend 'aref' submodule documentation now that it
     exists, and more updates to complete the ongoing move of 'ARef' and
     'AlwaysRefCounted' to 'sync::aref'.

   - 'list' module: add an example/test for 'ListLinksSelfPtr' usage.

   - 'alloc' module:

      - Implement 'Box::pin_slice()', which constructs a pinned slice of
        elements.

      - Provide information about the minimum alignment guarantees of
        'Kmalloc', 'Vmalloc' and 'KVmalloc'.

      - Take minimum alignment guarantees of allocators for
        'ForeignOwnable' into account.

      - Remove the 'allocator_test' (including 'Cmalloc').

      - Add doctest for 'Vec::as_slice()'.

      - Constify various methods.

   - 'time' module:

      - Add methods on 'HrTimer' that can only be called with exclusive
        access to an unarmed timer, or from timer callback context.

      - Add arithmetic operations to 'Instant' and 'Delta'.

      - Add a few convenience and access methods to 'HrTimer' and
        'Instant'.

  'macros' crate:

   - Reduce collections in 'quote!' macro.

  And a few other cleanups and improvements"

* tag 'rust-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (58 commits)
  gpu: nova-core: use Alignment for alignment-related operations
  rust: add `Alignment` type
  rust: macros: reduce collections in `quote!` macro
  rust: acpi: use `core::ffi::CStr` method names
  rust: of: use `core::ffi::CStr` method names
  rust: net: use `core::ffi::CStr` method names
  rust: miscdevice: use `core::ffi::CStr` method names
  rust: kunit: use `core::ffi::CStr` method names
  rust: firmware: use `core::ffi::CStr` method names
  rust: drm: use `core::ffi::CStr` method names
  rust: cpufreq: use `core::ffi::CStr` method names
  rust: configfs: use `core::ffi::CStr` method names
  rust: auxiliary: use `core::ffi::CStr` method names
  drm/panic: use `core::ffi::CStr` method names
  rust: device: use `kernel::{fmt,prelude::fmt!}`
  rust: sync: use `kernel::{fmt,prelude::fmt!}`
  rust: seq_file: use `kernel::{fmt,prelude::fmt!}`
  rust: kunit: use `kernel::{fmt,prelude::fmt!}`
  rust: file: use `kernel::{fmt,prelude::fmt!}`
  rust: device: use `kernel::{fmt,prelude::fmt!}`
  ...

44 files changed, 958 insertions, 228 deletions

diff --git a/rust/kernel/acpi.rs b/rust/kernel/acpi.rs
index 7ae317368b00..37e1161c1298 100644
--- a/rust/kernel/acpi.rs
+++ b/rust/kernel/acpi.rs
@@ -37,11 +37,8 @@ impl DeviceId {
     /// Create a new device id from an ACPI 'id' string.
     #[inline(always)]
     pub const fn new(id: &'static CStr) -> Self {
-        build_assert!(
-            id.len_with_nul() <= Self::ACPI_ID_LEN,
-            "ID exceeds 16 bytes"
-        );
-        let src = id.as_bytes_with_nul();
+        let src = id.to_bytes_with_nul();
+        build_assert!(src.len() <= Self::ACPI_ID_LEN, "ID exceeds 16 bytes");
         // Replace with `bindings::acpi_device_id::default()` once stabilized for `const`.
         // SAFETY: FFI type is valid to be zero-initialized.
         let mut acpi: bindings::acpi_device_id = unsafe { core::mem::zeroed() };
diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
index a2c49e5494d3..9c154209423c 100644
--- a/rust/kernel/alloc.rs
+++ b/rust/kernel/alloc.rs
@@ -2,18 +2,11 @@
 
 //! Implementation of the kernel's memory allocation infrastructure.
 
-#[cfg(not(any(test, testlib)))]
 pub mod allocator;
 pub mod kbox;
 pub mod kvec;
 pub mod layout;
 
-#[cfg(any(test, testlib))]
-pub mod allocator_test;
-
-#[cfg(any(test, testlib))]
-pub use self::allocator_test as allocator;
-
 pub use self::kbox::Box;
 pub use self::kbox::KBox;
 pub use self::kbox::KVBox;
@@ -137,6 +130,14 @@ pub mod flags {
 /// - Implementers must ensure that all trait functions abide by the guarantees documented in the
 ///   `# Guarantees` sections.
 pub unsafe trait Allocator {
+    /// The minimum alignment satisfied by all allocations from this allocator.
+    ///
+    /// # Guarantees
+    ///
+    /// Any pointer allocated by this allocator is guaranteed to be aligned to `MIN_ALIGN` even if
+    /// the requested layout has a smaller alignment.
+    const MIN_ALIGN: usize;
+
     /// Allocate memory based on `layout` and `flags`.
     ///
     /// On success, returns a buffer represented as `NonNull<[u8]>` that satisfies the layout
diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index 2692cf90c948..869d9fd69527 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -17,6 +17,8 @@ use crate::alloc::{AllocError, Allocator};
 use crate::bindings;
 use crate::pr_warn;
 
+const ARCH_KMALLOC_MINALIGN: usize = bindings::ARCH_KMALLOC_MINALIGN;
+
 /// The contiguous kernel allocator.
 ///
 /// `Kmalloc` is typically used for physically contiguous allocations up to page size, but also
@@ -128,6 +130,8 @@ impl Kmalloc {
 // - passing a pointer to a valid memory allocation is OK,
 // - `realloc` satisfies the guarantees, since `ReallocFunc::call` has the same.
 unsafe impl Allocator for Kmalloc {
+    const MIN_ALIGN: usize = ARCH_KMALLOC_MINALIGN;
+
     #[inline]
     unsafe fn realloc(
         ptr: Option<NonNull<u8>>,
@@ -147,6 +151,8 @@ unsafe impl Allocator for Kmalloc {
 // - passing a pointer to a valid memory allocation is OK,
 // - `realloc` satisfies the guarantees, since `ReallocFunc::call` has the same.
 unsafe impl Allocator for Vmalloc {
+    const MIN_ALIGN: usize = kernel::page::PAGE_SIZE;
+
     #[inline]
     unsafe fn realloc(
         ptr: Option<NonNull<u8>>,
@@ -171,6 +177,8 @@ unsafe impl Allocator for Vmalloc {
 // - passing a pointer to a valid memory allocation is OK,
 // - `realloc` satisfies the guarantees, since `ReallocFunc::call` has the same.
 unsafe impl Allocator for KVmalloc {
+    const MIN_ALIGN: usize = ARCH_KMALLOC_MINALIGN;
+
     #[inline]
     unsafe fn realloc(
         ptr: Option<NonNull<u8>>,
diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs
deleted file mode 100644
index 90dd987d40e4..000000000000
--- a/rust/kernel/alloc/allocator_test.rs
+++ /dev/null
@@ -1,124 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! So far the kernel's `Box` and `Vec` types can't be used by userspace test cases, since all users
-//! of those types (e.g. `CString`) use kernel allocators for instantiation.
-//!
-//! In order to allow userspace test cases to make use of such types as well, implement the
-//! `Cmalloc` allocator within the `allocator_test` module and type alias all kernel allocators to
-//! `Cmalloc`. The `Cmalloc` allocator uses libc's `realloc()` function as allocator backend.
-
-#![allow(missing_docs)]
-
-use super::{flags::*, AllocError, Allocator, Flags};
-use core::alloc::Layout;
-use core::cmp;
-use core::ptr;
-use core::ptr::NonNull;
-
-/// The userspace allocator based on libc.
-pub struct Cmalloc;
-
-pub type Kmalloc = Cmalloc;
-pub type Vmalloc = Kmalloc;
-pub type KVmalloc = Kmalloc;
-
-impl Cmalloc {
-    /// Returns a [`Layout`] that makes [`Kmalloc`] fulfill the requested size and alignment of
-    /// `layout`.
-    pub fn aligned_layout(layout: Layout) -> Layout {
-        // Note that `layout.size()` (after padding) is guaranteed to be a multiple of
-        // `layout.align()` which together with the slab guarantees means that `Kmalloc` will return
-        // a properly aligned object (see comments in `kmalloc()` for more information).
-        layout.pad_to_align()
-    }
-}
-
-extern "C" {
-    #[link_name = "aligned_alloc"]
-    fn libc_aligned_alloc(align: usize, size: usize) -> *mut crate::ffi::c_void;
-
-    #[link_name = "free"]
-    fn libc_free(ptr: *mut crate::ffi::c_void);
-}
-
-// SAFETY:
-// - memory remains valid until it is explicitly freed,
-// - passing a pointer to a valid memory allocation created by this `Allocator` is always OK,
-// - `realloc` provides the guarantees as provided in the `# Guarantees` section.
-unsafe impl Allocator for Cmalloc {
-    unsafe fn realloc(
-        ptr: Option<NonNull<u8>>,
-        layout: Layout,
-        old_layout: Layout,
-        flags: Flags,
-    ) -> Result<NonNull<[u8]>, AllocError> {
-        let src = match ptr {
-            Some(src) => {
-                if old_layout.size() == 0 {
-                    ptr::null_mut()
-                } else {
-                    src.as_ptr()
-                }
-            }
-            None => ptr::null_mut(),
-        };
-
-        if layout.size() == 0 {
-            // SAFETY: `src` is either NULL or was previously allocated with this `Allocator`
-            unsafe { libc_free(src.cast()) };
-
-            return Ok(NonNull::slice_from_raw_parts(
-                crate::alloc::dangling_from_layout(layout),
-                0,
-            ));
-        }
-
-        // ISO C (ISO/IEC 9899:2011) defines `aligned_alloc`:
-        //
-        // > The value of alignment shall be a valid alignment supported by the implementation
-        // [...].
-        //
-        // As an example of the "supported by the implementation" requirement, POSIX.1-2001 (IEEE
-        // 1003.1-2001) defines `posix_memalign`:
-        //
-        // > The value of alignment shall be a power of two multiple of sizeof (void *).
-        //
-        // and POSIX-based implementations of `aligned_alloc` inherit this requirement. At the time
-        // of writing, this is known to be the case on macOS (but not in glibc).
-        //
-        // Satisfy the stricter requirement to avoid spurious test failures on some platforms.
-        let min_align = core::mem::size_of::<*const crate::ffi::c_void>();
-        let layout = layout.align_to(min_align).map_err(|_| AllocError)?;
-        let layout = layout.pad_to_align();
-
-        // SAFETY: Returns either NULL or a pointer to a memory allocation that satisfies or
-        // exceeds the given size and alignment requirements.
-        let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) }.cast::<u8>();
-        let dst = NonNull::new(dst).ok_or(AllocError)?;
-
-        if flags.contains(__GFP_ZERO) {
-            // SAFETY: The preceding calls to `libc_aligned_alloc` and `NonNull::new`
-            // guarantee that `dst` points to memory of at least `layout.size()` bytes.
-            unsafe { dst.as_ptr().write_bytes(0, layout.size()) };
-        }
-
-        if !src.is_null() {
-            // SAFETY:
-            // - `src` has previously been allocated with this `Allocator`; `dst` has just been
-            //   newly allocated, hence the memory regions do not overlap.
-            // - both` src` and `dst` are properly aligned and valid for reads and writes
-            unsafe {
-                ptr::copy_nonoverlapping(
-                    src,
-                    dst.as_ptr(),
-                    cmp::min(layout.size(), old_layout.size()),
-                )
-            };
-        }
-
-        // SAFETY: `src` is either NULL or was previously allocated with this `Allocator`
-        unsafe { libc_free(src.cast()) };
-
-        Ok(NonNull::slice_from_raw_parts(dst, layout.size()))
-    }
-}
diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs
index 856d05aa60f1..27c4b5a9b61d 100644
--- a/rust/kernel/alloc/kbox.rs
+++ b/rust/kernel/alloc/kbox.rs
@@ -7,7 +7,6 @@ use super::allocator::{KVmalloc, Kmalloc, Vmalloc};
 use super::{AllocError, Allocator, Flags};
 use core::alloc::Layout;
 use core::borrow::{Borrow, BorrowMut};
-use core::fmt;
 use core::marker::PhantomData;
 use core::mem::ManuallyDrop;
 use core::mem::MaybeUninit;
@@ -17,6 +16,7 @@ use core::ptr::NonNull;
 use core::result::Result;
 
 use crate::ffi::c_void;
+use crate::fmt;
 use crate::init::InPlaceInit;
 use crate::types::ForeignOwnable;
 use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption};
@@ -290,6 +290,83 @@ where
         Ok(Self::new(x, flags)?.into())
     }
 
+    /// Construct a pinned slice of elements `Pin<Box<[T], A>>`.
+    ///
+    /// This is a convenient means for creation of e.g. slices of structrures containing spinlocks
+    /// or mutexes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::sync::{new_spinlock, SpinLock};
+    ///
+    /// struct Inner {
+    ///     a: u32,
+    ///     b: u32,
+    /// }
+    ///
+    /// #[pin_data]
+    /// struct Example {
+    ///     c: u32,
+    ///     #[pin]
+    ///     d: SpinLock<Inner>,
+    /// }
+    ///
+    /// impl Example {
+    ///     fn new() -> impl PinInit<Self, Error> {
+    ///         try_pin_init!(Self {
+    ///             c: 10,
+    ///             d <- new_spinlock!(Inner { a: 20, b: 30 }),
+    ///         })
+    ///     }
+    /// }
+    ///
+    /// // Allocate a boxed slice of 10 `Example`s.
+    /// let s = KBox::pin_slice(
+    ///     | _i | Example::new(),
+    ///     10,
+    ///     GFP_KERNEL
+    /// )?;
+    ///
+    /// assert_eq!(s[5].c, 10);
+    /// assert_eq!(s[3].d.lock().a, 20);
+    /// # Ok::<(), Error>(())
+    /// ```
+    pub fn pin_slice<Func, Item, E>(
+        mut init: Func,
+        len: usize,
+        flags: Flags,
+    ) -> Result<Pin<Box<[T], A>>, E>
+    where
+        Func: FnMut(usize) -> Item,
+        Item: PinInit<T, E>,
+        E: From<AllocError>,
+    {
+        let mut buffer = super::Vec::<T, A>::with_capacity(len, flags)?;
+        for i in 0..len {
+            let ptr = buffer.spare_capacity_mut().as_mut_ptr().cast();
+            // SAFETY:
+            // - `ptr` is a valid pointer to uninitialized memory.
+            // - `ptr` is not used if an error is returned.
+            // - `ptr` won't be moved until it is dropped, i.e. it is pinned.
+            unsafe { init(i).__pinned_init(ptr)? };
+
+            // SAFETY:
+            // - `i + 1 <= len`, hence we don't exceed the capacity, due to the call to
+            //   `with_capacity()` above.
+            // - The new value at index buffer.len() + 1 is the only element being added here, and
+            //   it has been initialized above by `init(i).__pinned_init(ptr)`.
+            unsafe { buffer.inc_len(1) };
+        }
+
+        let (ptr, _, _) = buffer.into_raw_parts();
+        let slice = core::ptr::slice_from_raw_parts_mut(ptr, len);
+
+        // SAFETY: `slice` points to an allocation allocated with `A` (`buffer`) and holds a valid
+        // `[T]`.
+        Ok(Pin::from(unsafe { Box::from_raw(slice) }))
+    }
+
     /// Convert a [`Box<T,A>`] to a [`Pin<Box<T,A>>`]. If `T` does not implement
     /// [`Unpin`], then `x` will be pinned in memory and can't be moved.
     pub fn into_pin(this: Self) -> Pin<Self> {
@@ -401,12 +478,17 @@ where
 }
 
 // SAFETY: The pointer returned by `into_foreign` comes from a well aligned
-// pointer to `T`.
+// pointer to `T` allocated by `A`.
 unsafe impl<T: 'static, A> ForeignOwnable for Box<T, A>
 where
     A: Allocator,
 {
-    const FOREIGN_ALIGN: usize = core::mem::align_of::<T>();
+    const FOREIGN_ALIGN: usize = if core::mem::align_of::<T>() < A::MIN_ALIGN {
+        A::MIN_ALIGN
+    } else {
+        core::mem::align_of::<T>()
+    };
+
     type Borrowed<'a> = &'a T;
     type BorrowedMut<'a> = &'a mut T;
 
@@ -435,12 +517,12 @@ where
 }
 
 // SAFETY: The pointer returned by `into_foreign` comes from a well aligned
-// pointer to `T`.
+// pointer to `T` allocated by `A`.
 unsafe impl<T: 'static, A> ForeignOwnable for Pin<Box<T, A>>
 where
     A: Allocator,
 {
-    const FOREIGN_ALIGN: usize = core::mem::align_of::<T>();
+    const FOREIGN_ALIGN: usize = <Box<T, A> as ForeignOwnable>::FOREIGN_ALIGN;
     type Borrowed<'a> = Pin<&'a T>;
     type BorrowedMut<'a> = Pin<&'a mut T>;
 
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index 3c72e0bdddb8..dfc101e03f35 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -7,9 +7,9 @@ use super::{
     layout::ArrayLayout,
     AllocError, Allocator, Box, Flags,
 };
+use crate::fmt;
 use core::{
     borrow::{Borrow, BorrowMut},
-    fmt,
     marker::PhantomData,
     mem::{ManuallyDrop, MaybeUninit},
     ops::Deref,
@@ -175,7 +175,7 @@ where
 
     /// Returns the number of elements that can be stored within the vector without allocating
     /// additional memory.
-    pub fn capacity(&self) -> usize {
+    pub const fn capacity(&self) -> usize {
         if const { Self::is_zst() } {
             usize::MAX
         } else {
@@ -185,7 +185,7 @@ where
 
     /// Returns the number of elements stored within the vector.
     #[inline]
-    pub fn len(&self) -> usize {
+    pub const fn len(&self) -> usize {
         self.len
     }
 
@@ -196,7 +196,7 @@ where
     /// - `additional` must be less than or equal to `self.capacity - self.len`.
     /// - All elements within the interval [`self.len`,`self.len + additional`) must be initialized.
     #[inline]
-    pub unsafe fn inc_len(&mut self, additional: usize) {
+    pub const unsafe fn inc_len(&mut self, additional: usize) {
         // Guaranteed by the type invariant to never underflow.
         debug_assert!(additional <= self.capacity() - self.len());
         // INVARIANT: By the safety requirements of this method this represents the exact number of
@@ -224,6 +224,16 @@ where
     }
 
     /// Returns a slice of the entire vector.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = KVec::new();
+    /// v.push(1, GFP_KERNEL)?;
+    /// v.push(2, GFP_KERNEL)?;
+    /// assert_eq!(v.as_slice(), &[1, 2]);
+    /// # Ok::<(), Error>(())
+    /// ```
     #[inline]
     pub fn as_slice(&self) -> &[T] {
         self
@@ -245,7 +255,7 @@ where
     /// Returns a raw pointer to the vector's backing buffer, or, if `T` is a ZST, a dangling raw
     /// pointer.
     #[inline]
-    pub fn as_ptr(&self) -> *const T {
+    pub const fn as_ptr(&self) -> *const T {
         self.ptr.as_ptr()
     }
 
@@ -261,7 +271,7 @@ where
     /// assert!(!v.is_empty());
     /// ```
     #[inline]
-    pub fn is_empty(&self) -> bool {
+    pub const fn is_empty(&self) -> bool {
         self.len() == 0
     }
 
@@ -1294,7 +1304,7 @@ impl<'vec, T> Drop for DrainAll<'vec, T> {
     }
 }
 
-#[macros::kunit_tests(rust_kvec_kunit)]
+#[macros::kunit_tests(rust_kvec)]
 mod tests {
     use super::*;
     use crate::prelude::*;
diff --git a/rust/kernel/alloc/kvec/errors.rs b/rust/kernel/alloc/kvec/errors.rs
index 348b8d27e102..21a920a4b09b 100644
--- a/rust/kernel/alloc/kvec/errors.rs
+++ b/rust/kernel/alloc/kvec/errors.rs
@@ -2,7 +2,7 @@
 
 //! Errors for the [`Vec`] type.
 
-use core::fmt::{self, Debug, Formatter};
+use kernel::fmt::{self, Debug, Formatter};
 use kernel::prelude::*;
 
 /// Error type for [`Vec::push_within_capacity`].
diff --git a/rust/kernel/alloc/layout.rs b/rust/kernel/alloc/layout.rs
index 93ed514f7cc7..52cbf61c4539 100644
--- a/rust/kernel/alloc/layout.rs
+++ b/rust/kernel/alloc/layout.rs
@@ -80,7 +80,7 @@ impl<T> ArrayLayout<T> {
     /// # Safety
     ///
     /// `len` must be a value, for which `len * size_of::<T>() <= isize::MAX` is true.
-    pub unsafe fn new_unchecked(len: usize) -> Self {
+    pub const unsafe fn new_unchecked(len: usize) -> Self {
         // INVARIANT: By the safety requirements of this function
         // `len * size_of::<T>() <= isize::MAX`.
         Self {
diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index 4749fb6bffef..58be09871397 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -105,8 +105,8 @@ pub struct DeviceId(bindings::auxiliary_device_id);
 impl DeviceId {
     /// Create a new [`DeviceId`] from name.
     pub const fn new(modname: &'static CStr, name: &'static CStr) -> Self {
-        let name = name.as_bytes_with_nul();
-        let modname = modname.as_bytes_with_nul();
+        let name = name.to_bytes_with_nul();
+        let modname = modname.to_bytes_with_nul();
 
         // TODO: Replace with `bindings::auxiliary_device_id::default()` once stabilized for
         // `const`.
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 831445d37181..61ea35bba7d5 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -82,7 +82,7 @@
 //!     Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?;
 //! let mut disk = gen_disk::GenDiskBuilder::new()
 //!     .capacity_sectors(4096)
-//!     .build(format_args!("myblk"), tagset)?;
+//!     .build(fmt!("myblk"), tagset)?;
 //!
 //! # Ok::<(), kernel::error::Error>(())
 //! ```
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index cd54cd64ea88..be92d0e5f031 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -3,12 +3,12 @@
 //! Generic disk abstraction.
 //!
 //! C header: [`include/linux/blkdev.h`](srctree/include/linux/blkdev.h)
-//! C header: [`include/linux/blk_mq.h`](srctree/include/linux/blk_mq.h)
+//! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h)
 
 use crate::block::mq::{raw_writer::RawWriter, Operations, TagSet};
+use crate::fmt::{self, Write};
 use crate::{bindings, error::from_err_ptr, error::Result, sync::Arc};
 use crate::{error, static_lock_class};
-use core::fmt::{self, Write};
 
 /// A builder for [`GenDisk`].
 ///
diff --git a/rust/kernel/block/mq/raw_writer.rs b/rust/kernel/block/mq/raw_writer.rs
index 7e2159e4f6a6..d311e24e2595 100644
--- a/rust/kernel/block/mq/raw_writer.rs
+++ b/rust/kernel/block/mq/raw_writer.rs
@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use core::fmt::{self, Write};
-
 use crate::error::Result;
+use crate::fmt::{self, Write};
 use crate::prelude::EINVAL;
 
 /// A mutable reference to a byte buffer where a string can be written into.
diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs
index 2736b798cdc6..9fb5ef825e41 100644
--- a/rust/kernel/configfs.rs
+++ b/rust/kernel/configfs.rs
@@ -263,7 +263,7 @@ impl<Data> Group<Data> {
         try_pin_init!(Self {
             group <- pin_init::init_zeroed().chain(|v: &mut Opaque<bindings::config_group>| {
                 let place = v.get();
-                let name = name.as_bytes_with_nul().as_ptr();
+                let name = name.to_bytes_with_nul().as_ptr();
                 // SAFETY: It is safe to initialize a group once it has been zeroed.
                 unsafe {
                     bindings::config_group_init_type_name(place, name.cast(), item_type.as_ptr())
@@ -613,7 +613,7 @@ where
     pub const fn new(name: &'static CStr) -> Self {
         Self {
             attribute: Opaque::new(bindings::configfs_attribute {
-                ca_name: name.as_char_ptr(),
+                ca_name: crate::str::as_char_ptr_in_const_context(name),
                 ca_owner: core::ptr::null_mut(),
                 ca_mode: 0o660,
                 show: Some(Self::show),
diff --git a/rust/kernel/cpu.rs b/rust/kernel/cpu.rs
index 5de730c8d817..cb6c0338ef5a 100644
--- a/rust/kernel/cpu.rs
+++ b/rust/kernel/cpu.rs
@@ -109,6 +109,7 @@ impl CpuId {
     /// unexpectedly due to preemption or CPU migration. It should only be
     /// used when the context ensures that the task remains on the same CPU
     /// or the users could use a stale (yet valid) CPU ID.
+    #[inline]
     pub fn current() -> Self {
         // SAFETY: raw_smp_processor_id() always returns a valid CPU ID.
         unsafe { Self::from_u32_unchecked(bindings::raw_smp_processor_id()) }
diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
index afc15e72a7c3..86c02e81729e 100644
--- a/rust/kernel/cpufreq.rs
+++ b/rust/kernel/cpufreq.rs
@@ -27,7 +27,6 @@ use crate::clk::Clk;
 use core::{
     cell::UnsafeCell,
     marker::PhantomData,
-    mem::MaybeUninit,
     ops::{Deref, DerefMut},
     pin::Pin,
     ptr,
@@ -1013,12 +1012,11 @@ impl<T: Driver> Registration<T> {
         } else {
             None
         },
-        // SAFETY: All zeros is a valid value for `bindings::cpufreq_driver`.
-        ..unsafe { MaybeUninit::zeroed().assume_init() }
+        ..pin_init::zeroed()
     };
 
     const fn copy_name(name: &'static CStr) -> [c_char; CPUFREQ_NAME_LEN] {
-        let src = name.as_bytes_with_nul();
+        let src = name.to_bytes_with_nul();
         let mut dst = [0; CPUFREQ_NAME_LEN];
 
         build_assert!(src.len() <= CPUFREQ_NAME_LEN);
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index a1db49eb159a..9cefa0810e0b 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -5,10 +5,10 @@
 //! C header: [`include/linux/device.h`](srctree/include/linux/device.h)
 
 use crate::{
-    bindings,
+    bindings, fmt,
     types::{ARef, ForeignOwnable, Opaque},
 };
-use core::{fmt, marker::PhantomData, ptr};
+use core::{marker::PhantomData, ptr};
 
 #[cfg(CONFIG_PRINTK)]
 use crate::c_str;
@@ -596,7 +596,7 @@ macro_rules! impl_device_context_into_aref {
 macro_rules! dev_printk {
     ($method:ident, $dev:expr, $($f:tt)*) => {
         {
-            ($dev).$method(::core::format_args!($($f)*));
+            ($dev).$method($crate::prelude::fmt!($($f)*));
         }
     }
 }
diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs
index 49ee12a906db..3a332a8c53a9 100644
--- a/rust/kernel/device/property.rs
+++ b/rust/kernel/device/property.rs
@@ -11,6 +11,7 @@ use crate::{
     alloc::KVec,
     bindings,
     error::{to_result, Result},
+    fmt,
     prelude::*,
     str::{CStr, CString},
     types::{ARef, Opaque},
@@ -68,16 +69,16 @@ impl FwNode {
         unsafe { bindings::is_of_node(self.as_raw()) }
     }
 
-    /// Returns an object that implements [`Display`](core::fmt::Display) for
+    /// Returns an object that implements [`Display`](fmt::Display) for
     /// printing the name of a node.
     ///
     /// This is an alternative to the default `Display` implementation, which
     /// prints the full path.
-    pub fn display_name(&self) -> impl core::fmt::Display + '_ {
+    pub fn display_name(&self) -> impl fmt::Display + '_ {
         struct FwNodeDisplayName<'a>(&'a FwNode);
 
-        impl core::fmt::Display for FwNodeDisplayName<'_> {
-            fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        impl fmt::Display for FwNodeDisplayName<'_> {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                 // SAFETY: `self` is valid by its type invariant.
                 let name = unsafe { bindings::fwnode_get_name(self.0.as_raw()) };
                 if name.is_null() {
@@ -87,7 +88,7 @@ impl FwNode {
                 // - `fwnode_get_name` returns null or a valid C string.
                 // - `name` was checked to be non-null.
                 let name = unsafe { CStr::from_char_ptr(name) };
-                write!(f, "{name}")
+                fmt::Display::fmt(name, f)
             }
         }
 
@@ -351,8 +352,8 @@ impl FwNodeReferenceArgs {
     }
 }
 
-impl core::fmt::Debug for FwNodeReferenceArgs {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl fmt::Debug for FwNodeReferenceArgs {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", self.as_slice())
     }
 }
@@ -377,8 +378,8 @@ enum Node<'a> {
     Owned(ARef<FwNode>),
 }
 
-impl core::fmt::Display for FwNode {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl fmt::Display for FwNode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // The logic here is the same as the one in lib/vsprintf.c
         // (fwnode_full_name_string).
 
@@ -413,9 +414,9 @@ impl core::fmt::Display for FwNode {
                 // SAFETY: `fwnode_get_name_prefix` returns null or a
                 // valid C string.
                 let prefix = unsafe { CStr::from_char_ptr(prefix) };
-                write!(f, "{prefix}")?;
+                fmt::Display::fmt(prefix, f)?;
             }
-            write!(f, "{}", fwnode.display_name())?;
+            fmt::Display::fmt(&fwnode.display_name(), f)?;
         }
 
         Ok(())
diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs
index 2bc8ab51ec28..68fe67624424 100644
--- a/rust/kernel/dma.rs
+++ b/rust/kernel/dma.rs
@@ -9,8 +9,8 @@ use crate::{
     device::{Bound, Core},
     error::{to_result, Result},
     prelude::*,
+    sync::aref::ARef,
     transmute::{AsBytes, FromBytes},
-    types::ARef,
 };
 
 /// Trait to be implemented by DMA capable bus devices.
diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs
index d29c477e89a8..0956ba0f64de 100644
--- a/rust/kernel/drm/device.rs
+++ b/rust/kernel/drm/device.rs
@@ -2,7 +2,7 @@
 
 //! DRM device.
 //!
-//! C header: [`include/linux/drm/drm_device.h`](srctree/include/linux/drm/drm_device.h)
+//! C header: [`include/drm/drm_device.h`](srctree/include/drm/drm_device.h)
 
 use crate::{
     alloc::allocator::Kmalloc,
@@ -82,8 +82,8 @@ impl<T: drm::Driver> Device<T> {
         major: T::INFO.major,
         minor: T::INFO.minor,
         patchlevel: T::INFO.patchlevel,
-        name: T::INFO.name.as_char_ptr().cast_mut(),
-        desc: T::INFO.desc.as_char_ptr().cast_mut(),
+        name: crate::str::as_char_ptr_in_const_context(T::INFO.name).cast_mut(),
+        desc: crate::str::as_char_ptr_in_const_context(T::INFO.desc).cast_mut(),
 
         driver_features: drm::driver::FEAT_GEM,
         ioctls: T::IOCTLS.as_ptr(),
diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs
index fe7e8d06961a..d2dad77274c4 100644
--- a/rust/kernel/drm/driver.rs
+++ b/rust/kernel/drm/driver.rs
@@ -2,7 +2,7 @@
 
 //! DRM driver core.
 //!
-//! C header: [`include/linux/drm/drm_drv.h`](srctree/include/linux/drm/drm_drv.h)
+//! C header: [`include/drm/drm_drv.h`](srctree/include/drm/drm_drv.h)
 
 use crate::{
     bindings, device, devres, drm,
diff --git a/rust/kernel/drm/file.rs b/rust/kernel/drm/file.rs
index e8789c9110d6..8c46f8d51951 100644
--- a/rust/kernel/drm/file.rs
+++ b/rust/kernel/drm/file.rs
@@ -2,7 +2,7 @@
 
 //! DRM File objects.
 //!
-//! C header: [`include/linux/drm/drm_file.h`](srctree/include/linux/drm/drm_file.h)
+//! C header: [`include/drm/drm_file.h`](srctree/include/drm/drm_file.h)
 
 use crate::{bindings, drm, error::Result, prelude::*, types::Opaque};
 use core::marker::PhantomData;
diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index b71821cfb5ea..b9f3248876ba 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -2,7 +2,7 @@
 
 //! DRM GEM API
 //!
-//! C header: [`include/linux/drm/drm_gem.h`](srctree/include/linux/drm/drm_gem.h)
+//! C header: [`include/drm/drm_gem.h`](srctree/include/drm/drm_gem.h)
 
 use crate::{
     alloc::flags::*,
diff --git a/rust/kernel/drm/ioctl.rs b/rust/kernel/drm/ioctl.rs
index fdec01c37168..8431cdcd3ae0 100644
--- a/rust/kernel/drm/ioctl.rs
+++ b/rust/kernel/drm/ioctl.rs
@@ -2,7 +2,7 @@
 
 //! DRM IOCTL definitions.
 //!
-//! C header: [`include/linux/drm/drm_ioctl.h`](srctree/include/linux/drm/drm_ioctl.h)
+//! C header: [`include/drm/drm_ioctl.h`](srctree/include/drm/drm_ioctl.h)
 
 use crate::ioctl;
 
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index a41de293dcd1..1c0e0e241daa 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -2,7 +2,9 @@
 
 //! Kernel errors.
 //!
-//! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)
+//! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)\
+//! C header: [`include/uapi/asm-generic/errno.h`](srctree/include/uapi/asm-generic/errno.h)\
+//! C header: [`include/linux/errno.h`](srctree/include/linux/errno.h)
 
 use crate::{
     alloc::{layout::LayoutError, AllocError},
@@ -101,8 +103,23 @@ pub struct Error(NonZeroI32);
 impl Error {
     /// Creates an [`Error`] from a kernel error code.
     ///
-    /// It is a bug to pass an out-of-range `errno`. `EINVAL` would
-    /// be returned in such a case.
+    /// `errno` must be within error code range (i.e. `>= -MAX_ERRNO && < 0`).
+    ///
+    /// It is a bug to pass an out-of-range `errno`. [`code::EINVAL`] is returned in such a case.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Error::from_errno(-1), EPERM);
+    /// assert_eq!(Error::from_errno(-2), ENOENT);
+    /// ```
+    ///
+    /// The following calls are considered a bug:
+    ///
+    /// ```
+    /// assert_eq!(Error::from_errno(0), EINVAL);
+    /// assert_eq!(Error::from_errno(-1000000), EINVAL);
+    /// ```
     pub fn from_errno(errno: crate::ffi::c_int) -> Error {
         if let Some(error) = Self::try_from_errno(errno) {
             error
@@ -158,7 +175,7 @@ impl Error {
     }
 
     /// Returns a string representing the error, if one exists.
-    #[cfg(not(any(test, testlib)))]
+    #[cfg(not(testlib))]
     pub fn name(&self) -> Option<&'static CStr> {
         // SAFETY: Just an FFI call, there are no extra safety requirements.
         let ptr = unsafe { bindings::errname(-self.0.get()) };
@@ -175,7 +192,7 @@ impl Error {
     /// When `testlib` is configured, this always returns `None` to avoid the dependency on a
     /// kernel function so that tests that use this (e.g., by calling [`Result::unwrap`]) can still
     /// run in userspace.
-    #[cfg(any(test, testlib))]
+    #[cfg(testlib)]
     pub fn name(&self) -> Option<&'static CStr> {
         None
     }
@@ -375,8 +392,43 @@ impl From<core::convert::Infallible> for Error {
 /// [Rust documentation]: https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html
 pub type Result<T = (), E = Error> = core::result::Result<T, E>;
 
-/// Converts an integer as returned by a C kernel function to an error if it's negative, and
-/// `Ok(())` otherwise.
+/// Converts an integer as returned by a C kernel function to a [`Result`].
+///
+/// If the integer is negative, an [`Err`] with an [`Error`] as given by [`Error::from_errno`] is
+/// returned. This means the integer must be `>= -MAX_ERRNO`.
+///
+/// Otherwise, it returns [`Ok`].
+///
+/// It is a bug to pass an out-of-range negative integer. `Err(EINVAL)` is returned in such a case.
+///
+/// # Examples
+///
+/// This function may be used to easily perform early returns with the [`?`] operator when working
+/// with C APIs within Rust abstractions:
+///
+/// ```
+/// # use kernel::error::to_result;
+/// # mod bindings {
+/// #     #![expect(clippy::missing_safety_doc)]
+/// #     use kernel::prelude::*;
+/// #     pub(super) unsafe fn f1() -> c_int { 0 }
+/// #     pub(super) unsafe fn f2() -> c_int { EINVAL.to_errno() }
+/// # }
+/// fn f() -> Result {
+///     // SAFETY: ...
+///     to_result(unsafe { bindings::f1() })?;
+///
+///     // SAFETY: ...
+///     to_result(unsafe { bindings::f2() })?;
+///
+///     // ...
+///
+///     Ok(())
+/// }
+/// # assert_eq!(f(), Err(EINVAL));
+/// ```
+///
+/// [`?`]: https://doc.rust-lang.org/reference/expressions/operator-expr.html#the-question-mark-operator
 pub fn to_result(err: crate::ffi::c_int) -> Result {
     if err < 0 {
         Err(Error::from_errno(err))
diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs
index 1abab5b2f052..94e6bb88b903 100644
--- a/rust/kernel/firmware.rs
+++ b/rust/kernel/firmware.rs
@@ -291,7 +291,7 @@ impl<const N: usize> ModInfoBuilder<N> {
         let module_name = this.module_name;
 
         if !this.module_name.is_empty() {
-            this = this.push_internal(module_name.as_bytes_with_nul());
+            this = this.push_internal(module_name.to_bytes_with_nul());
 
             if N != 0 {
                 // Re-use the space taken by the NULL terminator and swap it with the '.' separator.
diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs
index f1a3fa698745..cf06e73a6da0 100644
--- a/rust/kernel/fs/file.rs
+++ b/rust/kernel/fs/file.rs
@@ -11,6 +11,7 @@ use crate::{
     bindings,
     cred::Credential,
     error::{code::*, to_result, Error, Result},
+    fmt,
     sync::aref::{ARef, AlwaysRefCounted},
     types::{NotThreadSafe, Opaque},
 };
@@ -460,8 +461,8 @@ impl From<BadFdError> for Error {
     }
 }
 
-impl core::fmt::Debug for BadFdError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl fmt::Debug for BadFdError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.pad("EBADF")
     }
 }
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 41efd87595d6..3a43886cc14e 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -6,8 +6,8 @@
 //!
 //! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html>
 
+use crate::fmt;
 use crate::prelude::*;
-use core::fmt;
 
 #[cfg(CONFIG_PRINTK)]
 use crate::c_str;
@@ -74,14 +74,14 @@ macro_rules! kunit_assert {
                 // mistake (it is hidden to prevent that).
                 //
                 // This mimics KUnit's failed assertion format.
-                $crate::kunit::err(format_args!(
+                $crate::kunit::err($crate::prelude::fmt!(
                     "    # {}: ASSERTION FAILED at {FILE}:{LINE}\n",
                     $name
                 ));
-                $crate::kunit::err(format_args!(
+                $crate::kunit::err($crate::prelude::fmt!(
                     "    Expected {CONDITION} to be true, but is false\n"
                 ));
-                $crate::kunit::err(format_args!(
+                $crate::kunit::err($crate::prelude::fmt!(
                     "    Failure not reported to KUnit since this is a non-KUnit task\n"
                 ));
                 break 'out;
@@ -102,12 +102,12 @@ macro_rules! kunit_assert {
             unsafe impl Sync for UnaryAssert {}
 
             static LOCATION: Location = Location($crate::bindings::kunit_loc {
-                file: FILE.as_char_ptr(),
+                file: $crate::str::as_char_ptr_in_const_context(FILE),
                 line: LINE,
             });
             static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
                 assert: $crate::bindings::kunit_assert {},
-                condition: CONDITION.as_char_ptr(),
+                condition: $crate::str::as_char_ptr_in_const_context(CONDITION),
                 expected_true: true,
             });
 
@@ -202,7 +202,7 @@ pub const fn kunit_case(
 ) -> kernel::bindings::kunit_case {
     kernel::bindings::kunit_case {
         run_case: Some(run_case),
-        name: name.as_char_ptr(),
+        name: kernel::str::as_char_ptr_in_const_context(name),
         attr: kernel::bindings::kunit_attributes {
             speed: kernel::bindings::kunit_speed_KUNIT_SPEED_NORMAL,
         },
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index fef97f2a5098..f910a5ab80ba 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -17,6 +17,7 @@
 // the unstable features in use.
 //
 // Stable since Rust 1.79.0.
+#![feature(generic_nonzero)]
 #![feature(inline_const)]
 //
 // Stable since Rust 1.81.0.
@@ -28,6 +29,7 @@
 // Stable since Rust 1.83.0.
 #![feature(const_maybe_uninit_as_mut_ptr)]
 #![feature(const_mut_refs)]
+#![feature(const_option)]
 #![feature(const_ptr_write)]
 #![feature(const_refs_to_cell)]
 //
@@ -110,6 +112,7 @@ pub mod pid_namespace;
 pub mod platform;
 pub mod prelude;
 pub mod print;
+pub mod ptr;
 pub mod rbtree;
 pub mod regulator;
 pub mod revocable;
@@ -206,7 +209,7 @@ impl ThisModule {
     }
 }
 
-#[cfg(not(any(testlib, test)))]
+#[cfg(not(testlib))]
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
     pr_emerg!("{}\n", info);
diff --git a/rust/kernel/list.rs b/rust/kernel/list.rs
index 44e5219cfcbc..7355bbac16a7 100644
--- a/rust/kernel/list.rs
+++ b/rust/kernel/list.rs
@@ -38,6 +38,8 @@ pub use self::arc_field::{define_list_arc_field_getter, ListArcField};
 ///
 /// # Examples
 ///
+/// Use [`ListLinks`] as the type of the intrusive field.
+///
 /// ```
 /// use kernel::list::*;
 ///
@@ -140,6 +142,124 @@ pub use self::arc_field::{define_list_arc_field_getter, ListArcField};
 /// }
 /// # Result::<(), Error>::Ok(())
 /// ```
+///
+/// Use [`ListLinksSelfPtr`] as the type of the intrusive field. This allows a list of trait object
+/// type.
+///
+/// ```
+/// use kernel::list::*;
+///
+/// trait Foo {
+///     fn foo(&self) -> (&'static str, i32);
+/// }
+///
+/// #[pin_data]
+/// struct DTWrap<T: ?Sized> {
+///     #[pin]
+///     links: ListLinksSelfPtr<DTWrap<dyn Foo>>,
+///     value: T,
+/// }
+///
+/// impl<T> DTWrap<T> {
+///     fn new(value: T) -> Result<ListArc<Self>> {
+///         ListArc::pin_init(try_pin_init!(Self {
+///             value,
+///             links <- ListLinksSelfPtr::new(),
+///         }), GFP_KERNEL)
+///     }
+/// }
+///
+/// impl_list_arc_safe! {
+///     impl{T: ?Sized} ListArcSafe<0> for DTWrap<T> { untracked; }
+/// }
+/// impl_list_item! {
+///     impl ListItem<0> for DTWrap<dyn Foo> { using ListLinksSelfPtr { self.links }; }
+/// }
+///
+/// // Create a new empty list.
+/// let mut list = List::<DTWrap<dyn Foo>>::new();
+/// {
+///     assert!(list.is_empty());
+/// }
+///
+/// struct A(i32);
+/// // `A` returns the inner value for `foo`.
+/// impl Foo for A { fn foo(&self) -> (&'static str, i32) { ("a", self.0) } }
+///
+/// struct B;
+/// // `B` always returns 42.
+/// impl Foo for B { fn foo(&self) -> (&'static str, i32) { ("b", 42) } }
+///
+/// // Insert 3 element using `push_back()`.
+/// list.push_back(DTWrap::new(A(15))?);
+/// list.push_back(DTWrap::new(A(32))?);
+/// list.push_back(DTWrap::new(B)?);
+///
+/// // Iterate over the list to verify the nodes were inserted correctly.
+/// // [A(15), A(32), B]
+/// {
+///     let mut iter = list.iter();
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("a", 15));
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("a", 32));
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("b", 42));
+///     assert!(iter.next().is_none());
+///
+///     // Verify the length of the list.
+///     assert_eq!(list.iter().count(), 3);
+/// }
+///
+/// // Pop the items from the list using `pop_back()` and verify the content.
+/// {
+///     assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("b", 42));
+///     assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("a", 32));
+///     assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("a", 15));
+/// }
+///
+/// // Insert 3 elements using `push_front()`.
+/// list.push_front(DTWrap::new(A(15))?);
+/// list.push_front(DTWrap::new(A(32))?);
+/// list.push_front(DTWrap::new(B)?);
+///
+/// // Iterate over the list to verify the nodes were inserted correctly.
+/// // [B, A(32), A(15)]
+/// {
+///     let mut iter = list.iter();
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("b", 42));
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("a", 32));
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("a", 15));
+///     assert!(iter.next().is_none());
+///
+///     // Verify the length of the list.
+///     assert_eq!(list.iter().count(), 3);
+/// }
+///
+/// // Pop the items from the list using `pop_front()` and verify the content.
+/// {
+///     assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("a", 15));
+///     assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("a", 32));
+/// }
+///
+/// // Push `list2` to `list` through `push_all_back()`.
+/// // list: [B]
+/// // list2: [B, A(25)]
+/// {
+///     let mut list2 = List::<DTWrap<dyn Foo>>::new();
+///     list2.push_back(DTWrap::new(B)?);
+///     list2.push_back(DTWrap::new(A(25))?);
+///
+///     list.push_all_back(&mut list2);
+///
+///     // list: [B, B, A(25)]
+///     // list2: []
+///     let mut iter = list.iter();
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("b", 42));
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("b", 42));
+///     assert_eq!(iter.next().ok_or(EINVAL)?.value.foo(), ("a", 25));
+///     assert!(iter.next().is_none());
+///     assert!(list2.is_empty());
+/// }
+/// # Result::<(), Error>::Ok(())
+/// ```
 pub struct List<T: ?Sized + ListItem<ID>, const ID: u64 = 0> {
     first: *mut ListLinksFields,
     _ty: PhantomData<ListArc<T, ID>>,
diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs
index 6373fe183b27..d3aa7d25afad 100644
--- a/rust/kernel/miscdevice.rs
+++ b/rust/kernel/miscdevice.rs
@@ -34,7 +34,7 @@ impl MiscDeviceOptions {
         // SAFETY: All zeros is valid for this C type.
         let mut result: bindings::miscdevice = unsafe { MaybeUninit::zeroed().assume_init() };
         result.minor = bindings::MISC_DYNAMIC_MINOR as ffi::c_int;
-        result.name = self.name.as_char_ptr();
+        result.name = crate::str::as_char_ptr_in_const_context(self.name);
         result.fops = MiscdeviceVTable::<T>::build();
         result
     }
diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 7de5cc7a0eee..be1027b7961b 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -497,7 +497,7 @@ unsafe impl Sync for DriverVTable {}
 pub const fn create_phy_driver<T: Driver>() -> DriverVTable {
     // INVARIANT: All the fields of `struct phy_driver` are initialized properly.
     DriverVTable(Opaque::new(bindings::phy_driver {
-        name: T::NAME.as_char_ptr().cast_mut(),
+        name: crate::str::as_char_ptr_in_const_context(T::NAME).cast_mut(),
         flags: T::FLAGS,
         phy_id: T::PHY_DEVICE_ID.id(),
         phy_id_mask: T::PHY_DEVICE_ID.mask_as_int(),
diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs
index b76b35265df2..58b20c367f99 100644
--- a/rust/kernel/of.rs
+++ b/rust/kernel/of.rs
@@ -34,7 +34,7 @@ unsafe impl RawDeviceIdIndex for DeviceId {
 impl DeviceId {
     /// Create a new device id from an OF 'compatible' string.
     pub const fn new(compatible: &'static CStr) -> Self {
-        let src = compatible.as_bytes_with_nul();
+        let src = compatible.to_bytes_with_nul();
         // Replace with `bindings::of_device_id::default()` once stabilized for `const`.
         // SAFETY: FFI type is valid to be zero-initialized.
         let mut of: bindings::of_device_id = unsafe { core::mem::zeroed() };
diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
index 25fe97aafd02..198d09a31449 100644
--- a/rust/kernel/prelude.rs
+++ b/rust/kernel/prelude.rs
@@ -12,7 +12,10 @@
 //! ```
 
 #[doc(no_inline)]
-pub use core::pin::Pin;
+pub use core::{
+    mem::{align_of, align_of_val, size_of, size_of_val},
+    pin::Pin,
+};
 
 pub use ::ffi::{
     c_char, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint, c_ulong, c_ulonglong,
diff --git a/rust/kernel/ptr.rs b/rust/kernel/ptr.rs
new file mode 100644
index 000000000000..2e5e2a090480
--- /dev/null
+++ b/rust/kernel/ptr.rs
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Types and functions to work with pointers and addresses.
+
+use core::fmt::Debug;
+use core::mem::align_of;
+use core::num::NonZero;
+
+use crate::build_assert;
+
+/// Type representing an alignment, which is always a power of two.
+///
+/// It is used to validate that a given value is a valid alignment, and to perform masking and
+/// alignment operations.
+///
+/// This is a temporary substitute for the [`Alignment`] nightly type from the standard library,
+/// and to be eventually replaced by it.
+///
+/// [`Alignment`]: https://github.com/rust-lang/rust/issues/102070
+///
+/// # Invariants
+///
+/// An alignment is always a power of two.
+#[repr(transparent)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Alignment(NonZero<usize>);
+
+impl Alignment {
+    /// Validates that `ALIGN` is a power of two at build-time, and returns an [`Alignment`] of the
+    /// same value.
+    ///
+    /// A build error is triggered if `ALIGN` is not a power of two.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::Alignment;
+    ///
+    /// let v = Alignment::new::<16>();
+    /// assert_eq!(v.as_usize(), 16);
+    /// ```
+    #[inline(always)]
+    pub const fn new<const ALIGN: usize>() -> Self {
+        build_assert!(
+            ALIGN.is_power_of_two(),
+            "Provided alignment is not a power of two."
+        );
+
+        // INVARIANT: `align` is a power of two.
+        // SAFETY: `align` is a power of two, and thus non-zero.
+        Self(unsafe { NonZero::new_unchecked(ALIGN) })
+    }
+
+    /// Validates that `align` is a power of two at runtime, and returns an
+    /// [`Alignment`] of the same value.
+    ///
+    /// Returns [`None`] if `align` is not a power of two.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::Alignment;
+    ///
+    /// assert_eq!(Alignment::new_checked(16), Some(Alignment::new::<16>()));
+    /// assert_eq!(Alignment::new_checked(15), None);
+    /// assert_eq!(Alignment::new_checked(1), Some(Alignment::new::<1>()));
+    /// assert_eq!(Alignment::new_checked(0), None);
+    /// ```
+    #[inline(always)]
+    pub const fn new_checked(align: usize) -> Option<Self> {
+        if align.is_power_of_two() {
+            // INVARIANT: `align` is a power of two.
+            // SAFETY: `align` is a power of two, and thus non-zero.
+            Some(Self(unsafe { NonZero::new_unchecked(align) }))
+        } else {
+            None
+        }
+    }
+
+    /// Returns the alignment of `T`.
+    ///
+    /// 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.
+        const { Alignment::new_checked(align_of::<T>()).unwrap() }
+    }
+
+    /// Returns this alignment as a [`usize`].
+    ///
+    /// It is guaranteed to be a power of two.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::Alignment;
+    ///
+    /// assert_eq!(Alignment::new::<16>().as_usize(), 16);
+    /// ```
+    #[inline(always)]
+    pub const fn as_usize(self) -> usize {
+        self.as_nonzero().get()
+    }
+
+    /// Returns this alignment as a [`NonZero`].
+    ///
+    /// It is guaranteed to be a power of two.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::Alignment;
+    ///
+    /// assert_eq!(Alignment::new::<16>().as_nonzero().get(), 16);
+    /// ```
+    #[inline(always)]
+    pub const fn as_nonzero(self) -> NonZero<usize> {
+        // Allow the compiler to know that the value is indeed a power of two. This can help
+        // optimize some operations down the line, like e.g. replacing divisions by bit shifts.
+        if !self.0.is_power_of_two() {
+            // SAFETY: Per the invariants, `self.0` is always a power of two so this block will
+            // never be reached.
+            unsafe { core::hint::unreachable_unchecked() }
+        }
+        self.0
+    }
+
+    /// Returns the base-2 logarithm of the alignment.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::Alignment;
+    ///
+    /// assert_eq!(Alignment::of::<u8>().log2(), 0);
+    /// assert_eq!(Alignment::new::<16>().log2(), 4);
+    /// ```
+    #[inline(always)]
+    pub const fn log2(self) -> u32 {
+        self.0.ilog2()
+    }
+
+    /// Returns the mask for this alignment.
+    ///
+    /// This is equivalent to `!(self.as_usize() - 1)`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::Alignment;
+    ///
+    /// assert_eq!(Alignment::new::<0x10>().mask(), !0xf);
+    /// ```
+    #[inline(always)]
+    pub const fn mask(self) -> usize {
+        // No underflow can occur as the alignment is guaranteed to be a power of two, and thus is
+        // non-zero.
+        !(self.as_usize() - 1)
+    }
+}
+
+/// Trait for items that can be aligned against an [`Alignment`].
+pub trait Alignable: Sized {
+    /// Aligns `self` down to `alignment`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::{Alignable, Alignment};
+    ///
+    /// assert_eq!(0x2f_usize.align_down(Alignment::new::<0x10>()), 0x20);
+    /// assert_eq!(0x30usize.align_down(Alignment::new::<0x10>()), 0x30);
+    /// assert_eq!(0xf0u8.align_down(Alignment::new::<0x1000>()), 0x0);
+    /// ```
+    fn align_down(self, alignment: Alignment) -> Self;
+
+    /// Aligns `self` up to `alignment`, returning `None` if aligning would result in an overflow.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::ptr::{Alignable, Alignment};
+    ///
+    /// assert_eq!(0x4fusize.align_up(Alignment::new::<0x10>()), Some(0x50));
+    /// assert_eq!(0x40usize.align_up(Alignment::new::<0x10>()), Some(0x40));
+    /// assert_eq!(0x0usize.align_up(Alignment::new::<0x10>()), Some(0x0));
+    /// assert_eq!(u8::MAX.align_up(Alignment::new::<0x10>()), None);
+    /// assert_eq!(0x10u8.align_up(Alignment::new::<0x100>()), None);
+    /// assert_eq!(0x0u8.align_up(Alignment::new::<0x100>()), Some(0x0));
+    /// ```
+    fn align_up(self, alignment: Alignment) -> Option<Self>;
+}
+
+/// Implement [`Alignable`] for unsigned integer types.
+macro_rules! impl_alignable_uint {
+    ($($t:ty),*) => {
+        $(
+        impl Alignable for $t {
+            #[inline(always)]
+            fn align_down(self, alignment: Alignment) -> Self {
+                // The operands of `&` need to be of the same type so convert the alignment to
+                // `Self`. This means we need to compute the mask ourselves.
+                ::core::num::NonZero::<Self>::try_from(alignment.as_nonzero())
+                    .map(|align| self & !(align.get() - 1))
+                    // An alignment larger than `Self` always aligns down to `0`.
+                    .unwrap_or(0)
+            }
+
+            #[inline(always)]
+            fn align_up(self, alignment: Alignment) -> Option<Self> {
+                let aligned_down = self.align_down(alignment);
+                if self == aligned_down {
+                    Some(aligned_down)
+                } else {
+                    Self::try_from(alignment.as_usize())
+                        .ok()
+                        .and_then(|align| aligned_down.checked_add(align))
+                }
+            }
+        }
+        )*
+    };
+}
+
+impl_alignable_uint!(u8, u16, u32, u64, usize);
diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs
index 8f199b1a3bb1..59fbfc2473f8 100644
--- a/rust/kernel/seq_file.rs
+++ b/rust/kernel/seq_file.rs
@@ -4,7 +4,7 @@
 //!
 //! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.h)
 
-use crate::{bindings, c_str, types::NotThreadSafe, types::Opaque};
+use crate::{bindings, c_str, fmt, types::NotThreadSafe, types::Opaque};
 
 /// A utility for generating the contents of a seq file.
 #[repr(transparent)]
@@ -31,7 +31,7 @@ impl SeqFile {
 
     /// Used by the [`seq_print`] macro.
     #[inline]
-    pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
+    pub fn call_printf(&self, args: fmt::Arguments<'_>) {
         // SAFETY: Passing a void pointer to `Arguments` is valid for `%pA`.
         unsafe {
             bindings::seq_printf(
@@ -47,7 +47,7 @@ impl SeqFile {
 #[macro_export]
 macro_rules! seq_print {
     ($m:expr, $($arg:tt)+) => (
-        $m.call_printf(format_args!($($arg)+))
+        $m.call_printf($crate::prelude::fmt!($($arg)+))
     );
 }
 pub use seq_print;
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index 9298993ea7d8..289f77abf415 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -19,6 +19,7 @@
 use crate::{
     alloc::{AllocError, Flags, KBox},
     ffi::c_void,
+    fmt,
     init::InPlaceInit,
     sync::Refcount,
     try_init,
@@ -27,7 +28,6 @@ use crate::{
 use core::{
     alloc::Layout,
     borrow::{Borrow, BorrowMut},
-    fmt,
     marker::PhantomData,
     mem::{ManuallyDrop, MaybeUninit},
     ops::{Deref, DerefMut},
@@ -367,10 +367,10 @@ impl<T: ?Sized> Arc<T> {
     }
 }
 
-// SAFETY: The pointer returned by `into_foreign` comes from a well aligned
-// pointer to `ArcInner<T>`.
+// SAFETY: The pointer returned by `into_foreign` was originally allocated as an
+// `KBox<ArcInner<T>>`, so that type is what determines the alignment.
 unsafe impl<T: 'static> ForeignOwnable for Arc<T> {
-    const FOREIGN_ALIGN: usize = core::mem::align_of::<ArcInner<T>>();
+    const FOREIGN_ALIGN: usize = <KBox<ArcInner<T>> as ForeignOwnable>::FOREIGN_ALIGN;
 
     type Borrowed<'a> = ArcBorrow<'a, T>;
     type BorrowedMut<'a> = Self::Borrowed<'a>;
diff --git a/rust/kernel/sync/aref.rs b/rust/kernel/sync/aref.rs
index dbd77bb68617..0d24a0432015 100644
--- a/rust/kernel/sync/aref.rs
+++ b/rust/kernel/sync/aref.rs
@@ -1,6 +1,21 @@
 // SPDX-License-Identifier: GPL-2.0
 
 //! Internal reference counting support.
+//!
+//! Many C types already have their own reference counting mechanism (e.g. by storing a
+//! `refcount_t`). This module provides support for directly using their internal reference count
+//! from Rust; instead of making users have to use an additional Rust-reference count in the form of
+//! [`Arc`].
+//!
+//! The smart pointer [`ARef<T>`] acts similarly to [`Arc<T>`] in that it holds a refcount on the
+//! underlying object, but this refcount is internal to the object. It essentially is a Rust
+//! implementation of the `get_` and `put_` pattern used in C for reference counting.
+//!
+//! To make use of [`ARef<MyType>`], `MyType` needs to implement [`AlwaysRefCounted`]. It is a trait
+//! for accessing the internal reference count of an object of the `MyType` type.
+//!
+//! [`Arc`]: crate::sync::Arc
+//! [`Arc<T>`]: crate::sync::Arc
 
 use core::{marker::PhantomData, mem::ManuallyDrop, ops::Deref, ptr::NonNull};
 
@@ -97,7 +112,7 @@ impl<T: AlwaysRefCounted> ARef<T> {
     ///
     /// ```
     /// use core::ptr::NonNull;
-    /// use kernel::types::{ARef, AlwaysRefCounted};
+    /// use kernel::sync::aref::{ARef, AlwaysRefCounted};
     ///
     /// struct Empty {}
     ///
diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
index 7d0935bc325c..49fad6de0674 100644
--- a/rust/kernel/task.rs
+++ b/rust/kernel/task.rs
@@ -9,7 +9,8 @@ use crate::{
     ffi::{c_int, c_long, c_uint},
     mm::MmWithUser,
     pid_namespace::PidNamespace,
-    types::{ARef, NotThreadSafe, Opaque},
+    sync::aref::ARef,
+    types::{NotThreadSafe, Opaque},
 };
 use core::{
     cmp::{Eq, PartialEq},
@@ -76,7 +77,7 @@ macro_rules! current {
 /// incremented when creating `State` and decremented when it is dropped:
 ///
 /// ```
-/// use kernel::{task::Task, types::ARef};
+/// use kernel::{task::Task, sync::aref::ARef};
 ///
 /// struct State {
 ///     creator: ARef<Task>,
@@ -347,7 +348,7 @@ impl CurrentTask {
 }
 
 // SAFETY: The type invariants guarantee that `Task` is always refcounted.
-unsafe impl crate::types::AlwaysRefCounted for Task {
+unsafe impl crate::sync::aref::AlwaysRefCounted for Task {
     #[inline]
     fn inc_ref(&self) {
         // SAFETY: The existence of a shared reference means that the refcount is nonzero.
diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs
index 64c8dcf548d6..6ea98dfcd027 100644
--- a/rust/kernel/time.rs
+++ b/rust/kernel/time.rs
@@ -25,6 +25,7 @@
 //! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h).
 
 use core::marker::PhantomData;
+use core::ops;
 
 pub mod delay;
 pub mod hrtimer;
@@ -200,9 +201,31 @@ impl<C: ClockSource> Instant<C> {
     pub(crate) fn as_nanos(&self) -> i64 {
         self.inner
     }
+
+    /// Create an [`Instant`] from a `ktime_t` without checking if it is non-negative.
+    ///
+    /// # Panics
+    ///
+    /// On debug builds, this function will panic if `ktime` is not in the range from 0 to
+    /// `KTIME_MAX`.
+    ///
+    /// # Safety
+    ///
+    /// The caller promises that `ktime` is in the range from 0 to `KTIME_MAX`.
+    #[inline]
+    pub(crate) unsafe fn from_ktime(ktime: bindings::ktime_t) -> Self {
+        debug_assert!(ktime >= 0);
+
+        // INVARIANT: Our safety contract ensures that `ktime` is in the range from 0 to
+        // `KTIME_MAX`.
+        Self {
+            inner: ktime,
+            _c: PhantomData,
+        }
+    }
 }
 
-impl<C: ClockSource> core::ops::Sub for Instant<C> {
+impl<C: ClockSource> ops::Sub for Instant<C> {
     type Output = Delta;
 
     // By the type invariant, it never overflows.
@@ -214,6 +237,46 @@ impl<C: ClockSource> core::ops::Sub for Instant<C> {
     }
 }
 
+impl<T: ClockSource> ops::Add<Delta> for Instant<T> {
+    type Output = Self;
+
+    #[inline]
+    fn add(self, rhs: Delta) -> Self::Output {
+        // INVARIANT: With arithmetic over/underflow checks enabled, this will panic if we overflow
+        // (e.g. go above `KTIME_MAX`)
+        let res = self.inner + rhs.nanos;
+
+        // INVARIANT: With overflow checks enabled, we verify here that the value is >= 0
+        #[cfg(CONFIG_RUST_OVERFLOW_CHECKS)]
+        assert!(res >= 0);
+
+        Self {
+            inner: res,
+            _c: PhantomData,
+        }
+    }
+}
+
+impl<T: ClockSource> ops::Sub<Delta> for Instant<T> {
+    type Output = Self;
+
+    #[inline]
+    fn sub(self, rhs: Delta) -> Self::Output {
+        // INVARIANT: With arithmetic over/underflow checks enabled, this will panic if we overflow
+        // (e.g. go above `KTIME_MAX`)
+        let res = self.inner - rhs.nanos;
+
+        // INVARIANT: With overflow checks enabled, we verify here that the value is >= 0
+        #[cfg(CONFIG_RUST_OVERFLOW_CHECKS)]
+        assert!(res >= 0);
+
+        Self {
+            inner: res,
+            _c: PhantomData,
+        }
+    }
+}
+
 /// A span of time.
 ///
 /// This struct represents a span of time, with its value stored as nanoseconds.
@@ -224,6 +287,78 @@ pub struct Delta {
     nanos: i64,
 }
 
+impl ops::Add for Delta {
+    type Output = Self;
+
+    #[inline]
+    fn add(self, rhs: Self) -> Self {
+        Self {
+            nanos: self.nanos + rhs.nanos,
+        }
+    }
+}
+
+impl ops::AddAssign for Delta {
+    #[inline]
+    fn add_assign(&mut self, rhs: Self) {
+        self.nanos += rhs.nanos;
+    }
+}
+
+impl ops::Sub for Delta {
+    type Output = Self;
+
+    #[inline]
+    fn sub(self, rhs: Self) -> Self::Output {
+        Self {
+            nanos: self.nanos - rhs.nanos,
+        }
+    }
+}
+
+impl ops::SubAssign for Delta {
+    #[inline]
+    fn sub_assign(&mut self, rhs: Self) {
+        self.nanos -= rhs.nanos;
+    }
+}
+
+impl ops::Mul<i64> for Delta {
+    type Output = Self;
+
+    #[inline]
+    fn mul(self, rhs: i64) -> Self::Output {
+        Self {
+            nanos: self.nanos * rhs,
+        }
+    }
+}
+
+impl ops::MulAssign<i64> for Delta {
+    #[inline]
+    fn mul_assign(&mut self, rhs: i64) {
+        self.nanos *= rhs;
+    }
+}
+
+impl ops::Div for Delta {
+    type Output = i64;
+
+    #[inline]
+    fn div(self, rhs: Self) -> Self::Output {
+        #[cfg(CONFIG_64BIT)]
+        {
+            self.nanos / rhs.nanos
+        }
+
+        #[cfg(not(CONFIG_64BIT))]
+        {
+            // SAFETY: This function is always safe to call regardless of the input values
+            unsafe { bindings::div64_s64(self.nanos, rhs.nanos) }
+        }
+    }
+}
+
 impl Delta {
     /// A span of time equal to zero.
     pub const ZERO: Self = Self { nanos: 0 };
@@ -312,4 +447,30 @@ impl Delta {
             bindings::ktime_to_ms(self.as_nanos())
         }
     }
+
+    /// Return `self % dividend` where `dividend` is in nanoseconds.
+    ///
+    /// The kernel doesn't have any emulation for `s64 % s64` on 32 bit platforms, so this is
+    /// limited to 32 bit dividends.
+    #[inline]
+    pub fn rem_nanos(self, dividend: i32) -> Self {
+        #[cfg(CONFIG_64BIT)]
+        {
+            Self {
+                nanos: self.as_nanos() % i64::from(dividend),
+            }
+        }
+
+        #[cfg(not(CONFIG_64BIT))]
+        {
+            let mut rem = 0;
+
+            // SAFETY: `rem` is in the stack, so we can always provide a valid pointer to it.
+            unsafe { bindings::div_s64_rem(self.as_nanos(), dividend, &mut rem) };
+
+            Self {
+                nanos: i64::from(rem),
+            }
+        }
+    }
 }
diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs
index 144e3b57cc78..856d2d929a00 100644
--- a/rust/kernel/time/hrtimer.rs
+++ b/rust/kernel/time/hrtimer.rs
@@ -69,9 +69,14 @@
 
 use super::{ClockSource, Delta, Instant};
 use crate::{prelude::*, types::Opaque};
-use core::marker::PhantomData;
+use core::{marker::PhantomData, ptr::NonNull};
 use pin_init::PinInit;
 
+/// A type-alias to refer to the [`Instant<C>`] for a given `T` from [`HrTimer<T>`].
+///
+/// Where `C` is the [`ClockSource`] of the [`HrTimer`].
+pub type HrTimerInstant<T> = Instant<<<T as HasHrTimer<T>>::TimerMode as HrTimerMode>::Clock>;
+
 /// A timer backed by a C `struct hrtimer`.
 ///
 /// # Invariants
@@ -163,6 +168,84 @@ impl<T> HrTimer<T> {
         // handled on the C side.
         unsafe { bindings::hrtimer_cancel(c_timer_ptr) != 0 }
     }
+
+    /// Forward the timer expiry for a given timer pointer.
+    ///
+    /// # Safety
+    ///
+    /// - `self_ptr` must point to a valid `Self`.
+    /// - The caller must either have exclusive access to the data pointed at by `self_ptr`, or be
+    ///   within the context of the timer callback.
+    #[inline]
+    unsafe fn raw_forward(self_ptr: *mut Self, now: HrTimerInstant<T>, interval: Delta) -> u64
+    where
+        T: HasHrTimer<T>,
+    {
+        // SAFETY:
+        // * The C API requirements for this function are fulfilled by our safety contract.
+        // * `self_ptr` is guaranteed to point to a valid `Self` via our safety contract
+        unsafe {
+            bindings::hrtimer_forward(Self::raw_get(self_ptr), now.as_nanos(), interval.as_nanos())
+        }
+    }
+
+    /// Conditionally forward the timer.
+    ///
+    /// If the timer expires after `now`, this function does nothing and returns 0. If the timer
+    /// expired at or before `now`, this function forwards the timer by `interval` until the timer
+    /// expires after `now` and then returns the number of times the timer was forwarded by
+    /// `interval`.
+    ///
+    /// This function is mainly useful for timer types which can provide exclusive access to the
+    /// timer when the timer is not running. For forwarding the timer from within the timer callback
+    /// context, see [`HrTimerCallbackContext::forward()`].
+    ///
+    /// Returns the number of overruns that occurred as a result of the timer expiry change.
+    pub fn forward(self: Pin<&mut Self>, now: HrTimerInstant<T>, interval: Delta) -> u64
+    where
+        T: HasHrTimer<T>,
+    {
+        // SAFETY: `raw_forward` does not move `Self`
+        let this = unsafe { self.get_unchecked_mut() };
+
+        // SAFETY: By existence of `Pin<&mut Self>`, the pointer passed to `raw_forward` points to a
+        // valid `Self` that we have exclusive access to.
+        unsafe { Self::raw_forward(this, now, interval) }
+    }
+
+    /// Conditionally forward the timer.
+    ///
+    /// This is a variant of [`forward()`](Self::forward) that uses an interval after the current
+    /// time of the base clock for the [`HrTimer`].
+    pub fn forward_now(self: Pin<&mut Self>, interval: Delta) -> u64
+    where
+        T: HasHrTimer<T>,
+    {
+        self.forward(HrTimerInstant::<T>::now(), interval)
+    }
+
+    /// Return the time expiry for this [`HrTimer`].
+    ///
+    /// This value should only be used as a snapshot, as the actual expiry time could change after
+    /// this function is called.
+    pub fn expires(&self) -> HrTimerInstant<T>
+    where
+        T: HasHrTimer<T>,
+    {
+        // SAFETY: `self` is an immutable reference and thus always points to a valid `HrTimer`.
+        let c_timer_ptr = unsafe { HrTimer::raw_get(self) };
+
+        // SAFETY:
+        // - Timers cannot have negative ktime_t values as their expiration time.
+        // - There's no actual locking here, a racy read is fine and expected
+        unsafe {
+            Instant::from_ktime(
+                // This `read_volatile` is intended to correspond to a READ_ONCE call.
+                // FIXME(read_once): Replace with `read_once` when available on the Rust side.
+                core::ptr::read_volatile(&raw const ((*c_timer_ptr).node.expires)),
+            )
+        }
+    }
 }
 
 /// Implemented by pointer types that point to structs that contain a [`HrTimer`].
@@ -300,9 +383,13 @@ pub trait HrTimerCallback {
     type Pointer<'a>: RawHrTimerCallback;
 
     /// Called by the timer logic when the timer fires.
-    fn run(this: <Self::Pointer<'_> as RawHrTimerCallback>::CallbackTarget<'_>) -> HrTimerRestart
+    fn run(
+        this: <Self::Pointer<'_> as RawHrTimerCallback>::CallbackTarget<'_>,
+        ctx: HrTimerCallbackContext<'_, Self>,
+    ) -> HrTimerRestart
     where
-        Self: Sized;
+        Self: Sized,
+        Self: HasHrTimer<Self>;
 }
 
 /// A handle representing a potentially running timer.
@@ -324,6 +411,8 @@ pub unsafe trait HrTimerHandle {
     /// Note that the timer might be started by a concurrent start operation. If
     /// so, the timer might not be in the **stopped** state when this function
     /// returns.
+    ///
+    /// Returns `true` if the timer was running.
     fn cancel(&mut self) -> bool;
 }
 
@@ -585,6 +674,63 @@ impl<C: ClockSource> HrTimerMode for RelativePinnedHardMode<C> {
     type Expires = Delta;
 }
 
+/// Privileged smart-pointer for a [`HrTimer`] callback context.
+///
+/// Many [`HrTimer`] methods can only be called in two situations:
+///
+/// * When the caller has exclusive access to the `HrTimer` and the `HrTimer` is guaranteed not to
+///   be running.
+/// * From within the context of an `HrTimer`'s callback method.
+///
+/// This type provides access to said methods from within a timer callback context.
+///
+/// # Invariants
+///
+/// * The existence of this type means the caller is currently within the callback for an
+///   [`HrTimer`].
+/// * `self.0` always points to a live instance of [`HrTimer<T>`].
+pub struct HrTimerCallbackContext<'a, T: HasHrTimer<T>>(NonNull<HrTimer<T>>, PhantomData<&'a ()>);
+
+impl<'a, T: HasHrTimer<T>> HrTimerCallbackContext<'a, T> {
+    /// Create a new [`HrTimerCallbackContext`].
+    ///
+    /// # Safety
+    ///
+    /// This function relies on the caller being within the context of a timer callback, so it must
+    /// not be used anywhere except for within implementations of [`RawHrTimerCallback::run`]. The
+    /// caller promises that `timer` points to a valid initialized instance of
+    /// [`bindings::hrtimer`].
+    ///
+    /// The returned `Self` must not outlive the function context of [`RawHrTimerCallback::run`]
+    /// where this function is called.
+    pub(crate) unsafe fn from_raw(timer: *mut HrTimer<T>) -> Self {
+        // SAFETY: The caller guarantees `timer` is a valid pointer to an initialized
+        // `bindings::hrtimer`
+        // INVARIANT: Our safety contract ensures that we're within the context of a timer callback
+        // and that `timer` points to a live instance of `HrTimer<T>`.
+        Self(unsafe { NonNull::new_unchecked(timer) }, PhantomData)
+    }
+
+    /// Conditionally forward the timer.
+    ///
+    /// This function is identical to [`HrTimer::forward()`] except that it may only be used from
+    /// within the context of a [`HrTimer`] callback.
+    pub fn forward(&mut self, now: HrTimerInstant<T>, interval: Delta) -> u64 {
+        // SAFETY:
+        // - We are guaranteed to be within the context of a timer callback by our type invariants
+        // - By our type invariants, `self.0` always points to a valid `HrTimer<T>`
+        unsafe { HrTimer::<T>::raw_forward(self.0.as_ptr(), now, interval) }
+    }
+
+    /// Conditionally forward the timer.
+    ///
+    /// This is a variant of [`HrTimerCallbackContext::forward()`] that uses an interval after the
+    /// current time of the base clock for the [`HrTimer`].
+    pub fn forward_now(&mut self, duration: Delta) -> u64 {
+        self.forward(HrTimerInstant::<T>::now(), duration)
+    }
+}
+
 /// Use to implement the [`HasHrTimer<T>`] trait.
 ///
 /// See [`module`] documentation for an example.
diff --git a/rust/kernel/time/hrtimer/arc.rs b/rust/kernel/time/hrtimer/arc.rs
index ed490a7a8950..7be82bcb352a 100644
--- a/rust/kernel/time/hrtimer/arc.rs
+++ b/rust/kernel/time/hrtimer/arc.rs
@@ -3,6 +3,7 @@
 use super::HasHrTimer;
 use super::HrTimer;
 use super::HrTimerCallback;
+use super::HrTimerCallbackContext;
 use super::HrTimerHandle;
 use super::HrTimerMode;
 use super::HrTimerPointer;
@@ -99,6 +100,12 @@ where
         //    allocation from other `Arc` clones.
         let receiver = unsafe { ArcBorrow::from_raw(data_ptr) };
 
-        T::run(receiver).into_c()
+        // SAFETY:
+        // - By C API contract `timer_ptr` is the pointer that we passed when queuing the timer, so
+        //   it is a valid pointer to a `HrTimer<T>` embedded in a `T`.
+        // - We are within `RawHrTimerCallback::run`
+        let context = unsafe { HrTimerCallbackContext::from_raw(timer_ptr) };
+
+        T::run(receiver, context).into_c()
     }
 }
diff --git a/rust/kernel/time/hrtimer/pin.rs b/rust/kernel/time/hrtimer/pin.rs
index aef16d9ee2f0..4d39ef781697 100644
--- a/rust/kernel/time/hrtimer/pin.rs
+++ b/rust/kernel/time/hrtimer/pin.rs
@@ -3,6 +3,7 @@
 use super::HasHrTimer;
 use super::HrTimer;
 use super::HrTimerCallback;
+use super::HrTimerCallbackContext;
 use super::HrTimerHandle;
 use super::HrTimerMode;
 use super::RawHrTimerCallback;
@@ -103,6 +104,12 @@ where
         // here.
         let receiver_pin = unsafe { Pin::new_unchecked(receiver_ref) };
 
-        T::run(receiver_pin).into_c()
+        // SAFETY:
+        // - By C API contract `timer_ptr` is the pointer that we passed when queuing the timer, so
+        //   it is a valid pointer to a `HrTimer<T>` embedded in a `T`.
+        // - We are within `RawHrTimerCallback::run`
+        let context = unsafe { HrTimerCallbackContext::from_raw(timer_ptr) };
+
+        T::run(receiver_pin, context).into_c()
     }
 }
diff --git a/rust/kernel/time/hrtimer/pin_mut.rs b/rust/kernel/time/hrtimer/pin_mut.rs
index 767d0a4e8a2c..9d9447d4d57e 100644
--- a/rust/kernel/time/hrtimer/pin_mut.rs
+++ b/rust/kernel/time/hrtimer/pin_mut.rs
@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 
 use super::{
-    HasHrTimer, HrTimer, HrTimerCallback, HrTimerHandle, HrTimerMode, RawHrTimerCallback,
-    UnsafeHrTimerPointer,
+    HasHrTimer, HrTimer, HrTimerCallback, HrTimerCallbackContext, HrTimerHandle, HrTimerMode,
+    RawHrTimerCallback, UnsafeHrTimerPointer,
 };
 use core::{marker::PhantomData, pin::Pin, ptr::NonNull};
 
@@ -107,6 +107,12 @@ where
         // here.
         let receiver_pin = unsafe { Pin::new_unchecked(receiver_ref) };
 
-        T::run(receiver_pin).into_c()
+        // SAFETY:
+        // - By C API contract `timer_ptr` is the pointer that we passed when queuing the timer, so
+        //   it is a valid pointer to a `HrTimer<T>` embedded in a `T`.
+        // - We are within `RawHrTimerCallback::run`
+        let context = unsafe { HrTimerCallbackContext::from_raw(timer_ptr) };
+
+        T::run(receiver_pin, context).into_c()
     }
 }
diff --git a/rust/kernel/time/hrtimer/tbox.rs b/rust/kernel/time/hrtimer/tbox.rs
index ec08303315f2..aa1ee31a7195 100644
--- a/rust/kernel/time/hrtimer/tbox.rs
+++ b/rust/kernel/time/hrtimer/tbox.rs
@@ -3,6 +3,7 @@
 use super::HasHrTimer;
 use super::HrTimer;
 use super::HrTimerCallback;
+use super::HrTimerCallbackContext;
 use super::HrTimerHandle;
 use super::HrTimerMode;
 use super::HrTimerPointer;
@@ -119,6 +120,12 @@ where
         //   `data_ptr` exist.
         let data_mut_ref = unsafe { Pin::new_unchecked(&mut *data_ptr) };
 
-        T::run(data_mut_ref).into_c()
+        // SAFETY:
+        // - By C API contract `timer_ptr` is the pointer that we passed when queuing the timer, so
+        //   it is a valid pointer to a `HrTimer<T>` embedded in a `T`.
+        // - We are within `RawHrTimerCallback::run`
+        let context = unsafe { HrTimerCallbackContext::from_raw(timer_ptr) };
+
+        T::run(data_mut_ref, context).into_c()
     }
 }