Merge tag 'rust-6.8' of https://github.com/Rust-for-Linux/linux

Pull Rust updates from Miguel Ojeda:
 "Another routine one in terms of features. In terms of lines, this time
  the 'alloc' version upgrade is less prominent, given that it was
  fairly small (and we did not have two upgrades)

  Toolchain and infrastructure:

   - Upgrade to Rust 1.74.1

     The patch release includes a fix for an ICE that the Apple AGX GPU
     driver was hitting

   - Support 'srctree'-relative links in Rust code documentation

   - Automate part of the manual constants handling (i.e. the ones not
     recognised by 'bindgen')

   - Suppress searching builtin sysroot to avoid confusion with
     installed sysroots, needed for the to-be-merged arm64 support which
     uses a builtin target

   - Ignore '__preserve_most' functions for 'bindgen'

   - Reduce header inclusion bloat in exports

  'kernel' crate:

   - Implement 'Debug' for 'CString'

   - Make 'CondVar::wait()' an uninterruptible wait

  'macros' crate:

   - Update 'paste!' to accept string literals

   - Improve '#[vtable]' documentation

  Documentation:

   - Add testing section (KUnit and 'rusttest' target)

   - Remove 'CC=clang' mentions

   - Clarify that 'rustup override' applies to build directory"

* tag 'rust-6.8' of https://github.com/Rust-for-Linux/linux:
  docs: rust: Clarify that 'rustup override' applies to build directory
  docs: rust: Add rusttest info
  docs: rust: remove `CC=clang` mentions
  rust: support `srctree`-relative links
  rust: sync: Makes `CondVar::wait()` an uninterruptible wait
  rust: upgrade to Rust 1.74.1
  rust: Suppress searching builtin sysroot
  rust: macros: improve `#[vtable]` documentation
  rust: macros: update 'paste!' macro to accept string literals
  rust: bindings: rename const binding using sed
  rust: Ignore preserve-most functions
  rust: replace <linux/module.h> with <linux/export.h> in rust/exports.c
  rust: kernel: str: Implement Debug for CString

4 files changed, 112 insertions, 15 deletions

diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index 8cb4a31cf6e5..150e13750ff7 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -345,18 +345,31 @@ extern "Rust" {
     fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
 }
 
-/// Abort on memory allocation error or failure.
+/// Signal a memory allocation error.
 ///
-/// Callers of memory allocation APIs wishing to abort computation
+/// Callers of memory allocation APIs wishing to cease execution
 /// in response to an allocation error are encouraged to call this function,
-/// rather than directly invoking `panic!` or similar.
+/// rather than directly invoking [`panic!`] or similar.
 ///
-/// The default behavior of this function is to print a message to standard error
-/// and abort the process.
-/// It can be replaced with [`set_alloc_error_hook`] and [`take_alloc_error_hook`].
+/// This function is guaranteed to diverge (not return normally with a value), but depending on
+/// global configuration, it may either panic (resulting in unwinding or aborting as per
+/// configuration for all panics), or abort the process (with no unwinding).
+///
+/// The default behavior is:
+///
+///  * If the binary links against `std` (typically the case), then
+///   print a message to standard error and abort the process.
+///   This behavior can be replaced with [`set_alloc_error_hook`] and [`take_alloc_error_hook`].
+///   Future versions of Rust may panic by default instead.
+///
+/// * If the binary does not link against `std` (all of its crates are marked
+///   [`#![no_std]`][no_std]), then call [`panic!`] with a message.
+///   [The panic handler] applies as to any panic.
 ///
 /// [`set_alloc_error_hook`]: ../../std/alloc/fn.set_alloc_error_hook.html
 /// [`take_alloc_error_hook`]: ../../std/alloc/fn.take_alloc_error_hook.html
+/// [The panic handler]: https://doc.rust-lang.org/reference/runtime.html#the-panic_handler-attribute
+/// [no_std]: https://doc.rust-lang.org/reference/names/preludes.html#the-no_std-attribute
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[rustc_const_unstable(feature = "const_alloc_error", issue = "92523")]
 #[cfg(all(not(no_global_oom_handling), not(test)))]
@@ -397,9 +410,10 @@ pub mod __alloc_error_handler {
         if unsafe { __rust_alloc_error_handler_should_panic != 0 } {
             panic!("memory allocation of {size} bytes failed")
         } else {
-            core::panicking::panic_nounwind_fmt(format_args!(
-                "memory allocation of {size} bytes failed"
-            ))
+            core::panicking::panic_nounwind_fmt(
+                format_args!("memory allocation of {size} bytes failed"),
+                /* force_no_backtrace */ false,
+            )
         }
     }
 }
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
index 73b9ffd845d9..9c7ea73da108 100644
--- a/rust/alloc/lib.rs
+++ b/rust/alloc/lib.rs
@@ -90,8 +90,8 @@
 #![warn(missing_docs)]
 #![allow(explicit_outlives_requirements)]
 #![warn(multiple_supertrait_upcastable)]
-#![cfg_attr(not(bootstrap), allow(internal_features))]
-#![cfg_attr(not(bootstrap), allow(rustdoc::redundant_explicit_links))]
+#![allow(internal_features)]
+#![allow(rustdoc::redundant_explicit_links)]
 //
 // Library features:
 // tidy-alphabetical-start
@@ -122,6 +122,7 @@
 #![feature(const_waker)]
 #![feature(core_intrinsics)]
 #![feature(core_panic)]
+#![feature(deprecated_suggestion)]
 #![feature(dispatch_from_dyn)]
 #![feature(error_generic_member_access)]
 #![feature(error_in_core)]
@@ -145,7 +146,6 @@
 #![feature(ptr_metadata)]
 #![feature(ptr_sub_ptr)]
 #![feature(receiver_trait)]
-#![feature(saturating_int_impl)]
 #![feature(set_ptr_value)]
 #![feature(sized_type_properties)]
 #![feature(slice_from_ptr_range)]
diff --git a/rust/alloc/slice.rs b/rust/alloc/slice.rs
index 6ac463bd3edc..1181836da5f4 100644
--- a/rust/alloc/slice.rs
+++ b/rust/alloc/slice.rs
@@ -594,7 +594,7 @@ impl<T> [T] {
     /// ```
     #[rustc_allow_incoherent_impl]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[deprecated(since = "1.3.0", note = "renamed to join")]
+    #[deprecated(since = "1.3.0", note = "renamed to join", suggestion = "join")]
     pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
     where
         Self: Join<Separator>,
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
index 209a88cfe598..41ca71805ef0 100644
--- a/rust/alloc/vec/mod.rs
+++ b/rust/alloc/vec/mod.rs
@@ -1228,8 +1228,8 @@ impl<T, A: Allocator> Vec<T, A> {
     /// Shortens the vector, keeping the first `len` elements and dropping
     /// the rest.
     ///
-    /// If `len` is greater than the vector's current length, this has no
-    /// effect.
+    /// If `len` is greater or equal to the vector's current length, this has
+    /// no effect.
     ///
     /// The [`drain`] method can emulate `truncate`, but causes the excess
     /// elements to be returned instead of dropped.
@@ -1336,6 +1336,15 @@ impl<T, A: Allocator> Vec<T, A> {
     /// is never written to (except inside an `UnsafeCell`) using this pointer or any pointer
     /// derived from it. If you need to mutate the contents of the slice, use [`as_mut_ptr`].
     ///
+    /// This method guarantees that for the purpose of the aliasing model, this method
+    /// does not materialize a reference to the underlying slice, and thus the returned pointer
+    /// will remain valid when mixed with other calls to [`as_ptr`] and [`as_mut_ptr`].
+    /// Note that calling other methods that materialize mutable references to the slice,
+    /// or mutable references to specific elements you are planning on accessing through this pointer,
+    /// as well as writing to those elements, may still invalidate this pointer.
+    /// See the second example below for how this guarantee can be used.
+    ///
+    ///
     /// # Examples
     ///
     /// ```
@@ -1349,8 +1358,25 @@ impl<T, A: Allocator> Vec<T, A> {
     /// }
     /// ```
     ///
+    /// Due to the aliasing guarantee, the following code is legal:
+    ///
+    /// ```rust
+    /// unsafe {
+    ///     let mut v = vec![0, 1, 2];
+    ///     let ptr1 = v.as_ptr();
+    ///     let _ = ptr1.read();
+    ///     let ptr2 = v.as_mut_ptr().offset(2);
+    ///     ptr2.write(2);
+    ///     // Notably, the write to `ptr2` did *not* invalidate `ptr1`
+    ///     // because it mutated a different element:
+    ///     let _ = ptr1.read();
+    /// }
+    /// ```
+    ///
     /// [`as_mut_ptr`]: Vec::as_mut_ptr
+    /// [`as_ptr`]: Vec::as_ptr
     #[stable(feature = "vec_as_ptr", since = "1.37.0")]
+    #[cfg_attr(not(bootstrap), rustc_never_returns_null_ptr)]
     #[inline]
     pub fn as_ptr(&self) -> *const T {
         // We shadow the slice method of the same name to avoid going through
@@ -1366,6 +1392,15 @@ impl<T, A: Allocator> Vec<T, A> {
     /// Modifying the vector may cause its buffer to be reallocated,
     /// which would also make any pointers to it invalid.
     ///
+    /// This method guarantees that for the purpose of the aliasing model, this method
+    /// does not materialize a reference to the underlying slice, and thus the returned pointer
+    /// will remain valid when mixed with other calls to [`as_ptr`] and [`as_mut_ptr`].
+    /// Note that calling other methods that materialize references to the slice,
+    /// or references to specific elements you are planning on accessing through this pointer,
+    /// may still invalidate this pointer.
+    /// See the second example below for how this guarantee can be used.
+    ///
+    ///
     /// # Examples
     ///
     /// ```
@@ -1383,7 +1418,25 @@ impl<T, A: Allocator> Vec<T, A> {
     /// }
     /// assert_eq!(&*x, &[0, 1, 2, 3]);
     /// ```
+    ///
+    /// Due to the aliasing guarantee, the following code is legal:
+    ///
+    /// ```rust
+    /// unsafe {
+    ///     let mut v = vec![0];
+    ///     let ptr1 = v.as_mut_ptr();
+    ///     ptr1.write(1);
+    ///     let ptr2 = v.as_mut_ptr();
+    ///     ptr2.write(2);
+    ///     // Notably, the write to `ptr2` did *not* invalidate `ptr1`:
+    ///     ptr1.write(3);
+    /// }
+    /// ```
+    ///
+    /// [`as_mut_ptr`]: Vec::as_mut_ptr
+    /// [`as_ptr`]: Vec::as_ptr
     #[stable(feature = "vec_as_ptr", since = "1.37.0")]
+    #[cfg_attr(not(bootstrap), rustc_never_returns_null_ptr)]
     #[inline]
     pub fn as_mut_ptr(&mut self) -> *mut T {
         // We shadow the slice method of the same name to avoid going through
@@ -3404,6 +3457,36 @@ impl<T: Clone> From<&mut [T]> for Vec<T> {
 }
 
 #[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_array_ref", since = "1.74.0")]
+impl<T: Clone, const N: usize> From<&[T; N]> for Vec<T> {
+    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from(&[1, 2, 3]), vec![1, 2, 3]);
+    /// ```
+    fn from(s: &[T; N]) -> Vec<T> {
+        Self::from(s.as_slice())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_array_ref", since = "1.74.0")]
+impl<T: Clone, const N: usize> From<&mut [T; N]> for Vec<T> {
+    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);
+    /// ```
+    fn from(s: &mut [T; N]) -> Vec<T> {
+        Self::from(s.as_mut_slice())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
 #[stable(feature = "vec_from_array", since = "1.44.0")]
 impl<T, const N: usize> From<[T; N]> for Vec<T> {
     /// Allocate a `Vec<T>` and move `s`'s items into it.