Merge tag 'rust-6.5' of https://github.com/Rust-for-Linux/linux

Pull rust updates from Miguel Ojeda:
 "A fairly small one in terms of feature additions. Most of the changes
  in terms of lines come from the upgrade to the new version of the
  toolchain (which in turn is big due to the vendored 'alloc' crate).

  Upgrade to Rust 1.68.2:

   - This is the first such upgrade, and we will try to update it often
     from now on, in order to remain close to the latest release, until
     a minimum version (which is "in the future") can be established.

     The upgrade brings the stabilization of 4 features we used (and 2
     more that we used in our old 'rust' branch).

     Commit 3ed03f4 ("rust: upgrade to Rust 1.68.2") contains the
     details and rationale.

  pin-init API:

   - Several internal improvements and fixes to the pin-init API, e.g.
     allowing to use 'Self' in a struct definition with '#[pin_data]'.

  'error' module:

   - New 'name()' method for the 'Error' type (with 'errname()'
     integration), used to implement the 'Debug' trait for 'Error'.

   - Add error codes from 'include/linux/errno.h' to the list of Rust
     'Error' constants.

   - Allow specifying error type on the 'Result' type (with the default
     still being our usual 'Error' type).

  'str' module:

   - 'TryFrom' implementation for 'CStr', and new 'to_cstring()' method
     based on it.

  'sync' module:

   - Implement 'AsRef' trait for 'Arc', allowing to use 'Arc' in code
     that is generic over smart pointer types.

   - Add 'ptr_eq' method to 'Arc' for easier, less error prone
     comparison between two 'Arc' pointers.

   - Reword the 'Send' safety comment for 'Arc', and avoid referencing
     it from the 'Sync' one.

  'task' module:

   - Implement 'Send' marker for 'Task'.

  'types' module:

   - Implement 'Send' and 'Sync' markers for 'ARef<T>' when 'T' is
     'AlwaysRefCounted', 'Send' and 'Sync'.

  Other changes:

   - Documentation improvements and '.gitattributes' change to start
     using the Rust diff driver"

* tag 'rust-6.5' of https://github.com/Rust-for-Linux/linux:
  rust: error: `impl Debug` for `Error` with `errname()` integration
  rust: task: add `Send` marker to `Task`
  rust: specify when `ARef` is thread safe
  rust: sync: reword the `Arc` safety comment for `Sync`
  rust: sync: reword the `Arc` safety comment for `Send`
  rust: sync: implement `AsRef<T>` for `Arc<T>`
  rust: sync: add `Arc::ptr_eq`
  rust: error: add missing error codes
  rust: str: add conversion from `CStr` to `CString`
  rust: error: allow specifying error type on `Result`
  rust: init: update macro expansion example in docs
  rust: macros: replace Self with the concrete type in #[pin_data]
  rust: macros: refactor generics parsing of `#[pin_data]` into its own function
  rust: macros: fix usage of `#[allow]` in `quote!`
  docs: rust: point directly to the standalone installers
  .gitattributes: set diff driver for Rust source code files
  rust: upgrade to Rust 1.68.2
  rust: arc: fix intra-doc link in `Arc<T>::init`
  rust: alloc: clarify what is the upstream version

Author: torvalds

.gitattributes

@@ -2,3 +2,4 @@
 *.[ch] diff=cpp
 *.dts diff=dts
 *.dts[io] diff=dts
+*.rs diff=rust

Documentation/process/changes.rst

@@ -31,7 +31,7 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
-Rust (optional)        1.62.0           rustc --version
+Rust (optional)        1.68.2           rustc --version
 bindgen (optional)     0.56.0           bindgen --version
 GNU make               3.82             make --version
 bash                   4.2              bash --version

Documentation/rust/quick-start.rst

@@ -38,9 +38,9 @@ and run::
 
 	rustup override set $(scripts/min-tool-version.sh rustc)
 
-Otherwise, fetch a standalone installer or install ``rustup`` from:
+Otherwise, fetch a standalone installer from:
 
-	https://www.rust-lang.org
+	https://forge.rust-lang.org/infra/other-installation-methods.html#standalone
 
 
 Rust standard library source

rust/alloc/README.md

@@ -10,6 +10,9 @@ upstream. In general, only additions should be performed (e.g. new
 methods). Eventually, changes should make it into upstream so that,
 at some point, this fork can be dropped from the kernel tree.
 
+The Rust upstream version on top of which these files are based matches
+the output of `scripts/min-tool-version.sh rustc`.
+
 
 ## Rationale
 

rust/alloc/alloc.rs

@@ -22,21 +22,24 @@ use core::marker::Destruct;
 mod tests;
 
 extern "Rust" {
-    // These are the magic symbols to call the global allocator.  rustc generates
+    // These are the magic symbols to call the global allocator. rustc generates
     // them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute
     // (the code expanding that attribute macro generates those functions), or to call
-    // the default implementations in libstd (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
+    // the default implementations in std (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
     // otherwise.
-    // The rustc fork of LLVM also special-cases these function names to be able to optimize them
+    // The rustc fork of LLVM 14 and earlier also special-cases these function names to be able to optimize them
     // like `malloc`, `realloc`, and `free`, respectively.
     #[rustc_allocator]
-    #[rustc_allocator_nounwind]
+    #[rustc_nounwind]
     fn __rust_alloc(size: usize, align: usize) -> *mut u8;
-    #[rustc_allocator_nounwind]
+    #[rustc_deallocator]
+    #[rustc_nounwind]
     fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
-    #[rustc_allocator_nounwind]
+    #[rustc_reallocator]
+    #[rustc_nounwind]
     fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
-    #[rustc_allocator_nounwind]
+    #[rustc_allocator_zeroed]
+    #[rustc_nounwind]
     fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
 }
 
@@ -72,11 +75,14 @@ pub use std::alloc::Global;
 /// # Examples
 ///
 /// ```
-/// use std::alloc::{alloc, dealloc, Layout};
+/// use std::alloc::{alloc, dealloc, handle_alloc_error, Layout};
 ///
 /// unsafe {
 ///     let layout = Layout::new::<u16>();
 ///     let ptr = alloc(layout);
+///     if ptr.is_null() {
+///         handle_alloc_error(layout);
+///     }
 ///
 ///     *(ptr as *mut u16) = 42;
 ///     assert_eq!(*(ptr as *mut u16), 42);
@@ -349,7 +355,7 @@ pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Dest
 
 #[cfg(not(no_global_oom_handling))]
 extern "Rust" {
-    // This is the magic symbol to call the global alloc error handler.  rustc generates
+    // This is the magic symbol to call the global alloc error handler. rustc generates
     // it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
     // default implementations below (`__rdl_oom`) otherwise.
     fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
@@ -394,25 +400,24 @@ pub use std::alloc::handle_alloc_error;
 #[allow(unused_attributes)]
 #[unstable(feature = "alloc_internals", issue = "none")]
 pub mod __alloc_error_handler {
-    use crate::alloc::Layout;
-
-    // called via generated `__rust_alloc_error_handler`
-
-    // if there is no `#[alloc_error_handler]`
+    // called via generated `__rust_alloc_error_handler` if there is no
+    // `#[alloc_error_handler]`.
     #[rustc_std_internal_symbol]
-    pub unsafe extern "C-unwind" fn __rdl_oom(size: usize, _align: usize) -> ! {
-        panic!("memory allocation of {size} bytes failed")
-    }
-
-    // if there is an `#[alloc_error_handler]`
-    #[rustc_std_internal_symbol]
-    pub unsafe extern "C-unwind" fn __rg_oom(size: usize, align: usize) -> ! {
-        let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
+    pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
         extern "Rust" {
-            #[lang = "oom"]
-            fn oom_impl(layout: Layout) -> !;
+            // This symbol is emitted by rustc next to __rust_alloc_error_handler.
+            // Its value depends on the -Zoom={panic,abort} compiler option.
+            static __rust_alloc_error_handler_should_panic: u8;
+        }
+
+        #[allow(unused_unsafe)]
+        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"
+            ))
         }
-        unsafe { oom_impl(layout) }
     }
 }