Merge tag 'rust-6.2' of https://github.com/Rust-for-Linux/linux

Pull rust updates from Miguel Ojeda:
 "The first set of changes after the merge, the major ones being:

   - String and formatting: new types 'CString', 'CStr', 'BStr' and
     'Formatter'; new macros 'c_str!', 'b_str!' and 'fmt!'.

   - Errors: the rest of the error codes from 'errno-base.h', as well as
     some 'From' trait implementations for the 'Error' type.

   - Printing: the rest of the 'pr_*!' levels and the continuation one
     'pr_cont!', as well as a new sample.

   - 'alloc' crate: new constructors 'try_with_capacity()' and
     'try_with_capacity_in()' for 'RawVec' and 'Vec'.

   - Procedural macros: new macros '#[vtable]' and 'concat_idents!', as
     well as better ergonomics for 'module!' users.

   - Asserting: new macros 'static_assert!', 'build_error!' and
     'build_assert!', as well as a new crate 'build_error' to support
     them.

   - Vocabulary types: new types 'Opaque' and 'Either'.

   - Debugging: new macro 'dbg!'"

* tag 'rust-6.2' of https://github.com/Rust-for-Linux/linux: (28 commits)
  rust: types: add `Opaque` type
  rust: types: add `Either` type
  rust: build_assert: add `build_{error,assert}!` macros
  rust: add `build_error` crate
  rust: static_assert: add `static_assert!` macro
  rust: std_vendor: add `dbg!` macro based on `std`'s one
  rust: str: add `fmt!` macro
  rust: str: add `CString` type
  rust: str: add `Formatter` type
  rust: str: add `c_str!` macro
  rust: str: add `CStr` unit tests
  rust: str: implement several traits for `CStr`
  rust: str: add `CStr` type
  rust: str: add `b_str!` macro
  rust: str: add `BStr` type
  rust: alloc: add `Vec::try_with_capacity{,_in}()` constructors
  rust: alloc: add `RawVec::try_with_capacity_in()` constructor
  rust: prelude: add `error::code::*` constant items
  rust: error: add `From` implementations for `Error`
  rust: error: add codes from `errno-base.h`
  ...

1 files changed, 163 insertions, 0 deletions

diff --git a/rust/kernel/std_vendor.rs b/rust/kernel/std_vendor.rs
new file mode 100644
index 000000000000..b3e68b24a8c6
--- /dev/null
+++ b/rust/kernel/std_vendor.rs
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! The contents of this file come from the Rust standard library, hosted in
+//! the <https://github.com/rust-lang/rust> repository, licensed under
+//! "Apache-2.0 OR MIT" and adapted for kernel use. For copyright details,
+//! see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>.
+
+/// [`std::dbg`], but using [`pr_info`] instead of [`eprintln`].
+///
+/// Prints and returns the value of a given expression for quick and dirty
+/// debugging.
+///
+/// An example:
+///
+/// ```rust
+/// let a = 2;
+/// # #[allow(clippy::dbg_macro)]
+/// let b = dbg!(a * 2) + 1;
+/// //      ^-- prints: [src/main.rs:2] a * 2 = 4
+/// assert_eq!(b, 5);
+/// ```
+///
+/// The macro works by using the `Debug` implementation of the type of
+/// the given expression to print the value with [`printk`] along with the
+/// source location of the macro invocation as well as the source code
+/// of the expression.
+///
+/// Invoking the macro on an expression moves and takes ownership of it
+/// before returning the evaluated expression unchanged. If the type
+/// of the expression does not implement `Copy` and you don't want
+/// to give up ownership, you can instead borrow with `dbg!(&expr)`
+/// for some expression `expr`.
+///
+/// The `dbg!` macro works exactly the same in release builds.
+/// This is useful when debugging issues that only occur in release
+/// builds or when debugging in release mode is significantly faster.
+///
+/// Note that the macro is intended as a temporary debugging tool to be
+/// used during development. Therefore, avoid committing `dbg!` macro
+/// invocations into the kernel tree.
+///
+/// For debug output that is intended to be kept in the kernel tree,
+/// use [`pr_debug`] and similar facilities instead.
+///
+/// # Stability
+///
+/// The exact output printed by this macro should not be relied upon
+/// and is subject to future changes.
+///
+/// # Further examples
+///
+/// With a method call:
+///
+/// ```rust
+/// # #[allow(clippy::dbg_macro)]
+/// fn foo(n: usize) {
+///     if dbg!(n.checked_sub(4)).is_some() {
+///         // ...
+///     }
+/// }
+///
+/// foo(3)
+/// ```
+///
+/// This prints to the kernel log:
+///
+/// ```text,ignore
+/// [src/main.rs:4] n.checked_sub(4) = None
+/// ```
+///
+/// Naive factorial implementation:
+///
+/// ```rust
+/// # #[allow(clippy::dbg_macro)]
+/// # {
+/// fn factorial(n: u32) -> u32 {
+///     if dbg!(n <= 1) {
+///         dbg!(1)
+///     } else {
+///         dbg!(n * factorial(n - 1))
+///     }
+/// }
+///
+/// dbg!(factorial(4));
+/// # }
+/// ```
+///
+/// This prints to the kernel log:
+///
+/// ```text,ignore
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = true
+/// [src/main.rs:4] 1 = 1
+/// [src/main.rs:5] n * factorial(n - 1) = 2
+/// [src/main.rs:5] n * factorial(n - 1) = 6
+/// [src/main.rs:5] n * factorial(n - 1) = 24
+/// [src/main.rs:11] factorial(4) = 24
+/// ```
+///
+/// The `dbg!(..)` macro moves the input:
+///
+/// ```ignore
+/// /// A wrapper around `usize` which importantly is not Copyable.
+/// #[derive(Debug)]
+/// struct NoCopy(usize);
+///
+/// let a = NoCopy(42);
+/// let _ = dbg!(a); // <-- `a` is moved here.
+/// let _ = dbg!(a); // <-- `a` is moved again; error!
+/// ```
+///
+/// You can also use `dbg!()` without a value to just print the
+/// file and line whenever it's reached.
+///
+/// Finally, if you want to `dbg!(..)` multiple values, it will treat them as
+/// a tuple (and return it, too):
+///
+/// ```
+/// # #[allow(clippy::dbg_macro)]
+/// assert_eq!(dbg!(1usize, 2u32), (1, 2));
+/// ```
+///
+/// However, a single argument with a trailing comma will still not be treated
+/// as a tuple, following the convention of ignoring trailing commas in macro
+/// invocations. You can use a 1-tuple directly if you need one:
+///
+/// ```
+/// # #[allow(clippy::dbg_macro)]
+/// # {
+/// assert_eq!(1, dbg!(1u32,)); // trailing comma ignored
+/// assert_eq!((1,), dbg!((1u32,))); // 1-tuple
+/// # }
+/// ```
+///
+/// [`std::dbg`]: https://doc.rust-lang.org/std/macro.dbg.html
+/// [`eprintln`]: https://doc.rust-lang.org/std/macro.eprintln.html
+/// [`printk`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html
+#[macro_export]
+macro_rules! dbg {
+    // NOTE: We cannot use `concat!` to make a static string as a format argument
+    // of `pr_info!` because `file!` could contain a `{` or
+    // `$val` expression could be a block (`{ .. }`), in which case the `pr_info!`
+    // will be malformed.
+    () => {
+        $crate::pr_info!("[{}:{}]\n", ::core::file!(), ::core::line!())
+    };
+    ($val:expr $(,)?) => {
+        // Use of `match` here is intentional because it affects the lifetimes
+        // of temporaries - https://stackoverflow.com/a/48732525/1063961
+        match $val {
+            tmp => {
+                $crate::pr_info!("[{}:{}] {} = {:#?}\n",
+                    ::core::file!(), ::core::line!(), ::core::stringify!($val), &tmp);
+                tmp
+            }
+        }
+    };
+    ($($val:expr),+ $(,)?) => {
+        ($($crate::dbg!($val)),+,)
+    };
+}