Merge tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

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

   - Extract the 'pin-init' API from the 'kernel' crate and make it into
     a standalone crate.

     In order to do this, the contents are rearranged so that they can
     easily be kept in sync with the version maintained out-of-tree that
     other projects have started to use too (or plan to, like QEMU).

     This will reduce the maintenance burden for Benno, who will now
     have his own sub-tree, and will simplify future expected changes
     like the move to use 'syn' to simplify the implementation.

   - Add '#[test]'-like support based on KUnit.

     We already had doctests support based on KUnit, which takes the
     examples in our Rust documentation and runs them under KUnit.

     Now, we are adding the beginning of the support for "normal" tests,
     similar to those the '#[test]' tests in userspace Rust. For
     instance:

         #[kunit_tests(my_suite)]
         mod tests {
             #[test]
             fn my_test() {
                 assert_eq!(1 + 1, 2);
             }
         }

     Unlike with doctests, the 'assert*!'s do not map to the KUnit
     assertion APIs yet.

   - Check Rust signatures at compile time for functions called from C
     by name.

     In particular, introduce a new '#[export]' macro that can be placed
     in the Rust function definition. It will ensure that the function
     declaration on the C side matches the signature on the Rust
     function:

         #[export]
         pub unsafe extern "C" fn my_function(a: u8, b: i32) -> usize {
             // ...
         }

     The macro essentially forces the compiler to compare the types of
     the actual Rust function and the 'bindgen'-processed C signature.

     These cases are rare so far. In the future, we may consider
     introducing another tool, 'cbindgen', to generate C headers
     automatically. Even then, having these functions explicitly marked
     may be a good idea anyway.

   - Enable the 'raw_ref_op' Rust feature: it is already stable, and
     allows us to use the new '&raw' syntax, avoiding a couple macros.
     After everyone has migrated, we will disallow the macros.

   - Pass the correct target to 'bindgen' on Usermode Linux.

   - Fix 'rusttest' build in macOS.

  'kernel' crate:

   - New 'hrtimer' module: add support for setting up intrusive timers
     without allocating when starting the timer. Add support for
     'Pin<Box<_>>', 'Arc<_>', 'Pin<&_>' and 'Pin<&mut _>' as pointer
     types for use with timer callbacks. Add support for setting clock
     source and timer mode.

   - New 'dma' module: add a simple DMA coherent allocator abstraction
     and a test sample driver.

   - 'list' module: make the linked list 'Cursor' point between
     elements, rather than at an element, which is more convenient to us
     and allows for cursors to empty lists; and document it with
     examples of how to perform common operations with the provided
     methods.

   - 'str' module: implement a few traits for 'BStr' as well as the
     'strip_prefix()' method.

   - 'sync' module: add 'Arc::as_ptr'.

   - 'alloc' module: add 'Box::into_pin'.

   - 'error' module: extend the 'Result' documentation, including a few
     examples on different ways of handling errors, a warning about
     using methods that may panic, and links to external documentation.

  'macros' crate:

   - 'module' macro: add the 'authors' key to support multiple authors.
     The original key will be kept until everyone has migrated.

  Documentation:

   - Add error handling sections.

  MAINTAINERS:

   - Add Danilo Krummrich as reviewer of the Rust "subsystem".

   - Add 'RUST [PIN-INIT]' entry with Benno Lossin as maintainer. It has
     its own sub-tree.

   - Add sub-tree for 'RUST [ALLOC]'.

   - Add 'DMA MAPPING HELPERS DEVICE DRIVER API [RUST]' entry with
     Abdiel Janulgue as primary maintainer. It will go through the
     sub-tree of the 'RUST [ALLOC]' entry.

   - Add 'HIGH-RESOLUTION TIMERS [RUST]' entry with Andreas Hindborg as
     maintainer. It has its own sub-tree.

  And a few other cleanups and improvements"

* tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (71 commits)
  rust: dma: add `Send` implementation for `CoherentAllocation`
  rust: macros: fix `make rusttest` build on macOS
  rust: block: refactor to use `&raw mut`
  rust: enable `raw_ref_op` feature
  rust: uaccess: name the correct function
  rust: rbtree: fix comments referring to Box instead of KBox
  rust: hrtimer: add maintainer entry
  rust: hrtimer: add clocksource selection through `ClockId`
  rust: hrtimer: add `HrTimerMode`
  rust: hrtimer: implement `HrTimerPointer` for `Pin<Box<T>>`
  rust: alloc: add `Box::into_pin`
  rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>`
  rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>`
  rust: hrtimer: add `hrtimer::ScopedHrTimerPointer`
  rust: hrtimer: add `UnsafeHrTimerPointer`
  rust: hrtimer: allow timer restart from timer handler
  rust: str: implement `strip_prefix` for `BStr`
  rust: str: implement `AsRef<BStr>` for `[u8]` and `BStr`
  rust: str: implement `Index` for `BStr`
  rust: str: implement `PartialEq` for `BStr`
  ...

1 files changed, 46 insertions, 118 deletions

diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
index d61bc6a56425e..9acaa68c974e8 100644
--- a/rust/macros/lib.rs
+++ b/rust/macros/lib.rs
@@ -9,13 +9,12 @@
 #[macro_use]
 mod quote;
 mod concat_idents;
+mod export;
 mod helpers;
+mod kunit;
 mod module;
 mod paste;
-mod pin_data;
-mod pinned_drop;
 mod vtable;
-mod zeroable;
 
 use proc_macro::TokenStream;
 
@@ -36,7 +35,7 @@ use proc_macro::TokenStream;
 /// module!{
 ///     type: MyModule,
 ///     name: "my_kernel_module",
-///     author: "Rust for Linux Contributors",
+///     authors: ["Rust for Linux Contributors"],
 ///     description: "My very own kernel module!",
 ///     license: "GPL",
 ///     alias: ["alternate_module_name"],
@@ -69,7 +68,7 @@ use proc_macro::TokenStream;
 /// module!{
 ///     type: MyDeviceDriverModule,
 ///     name: "my_device_driver_module",
-///     author: "Rust for Linux Contributors",
+///     authors: ["Rust for Linux Contributors"],
 ///     description: "My device driver requires firmware",
 ///     license: "GPL",
 ///     firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"],
@@ -88,7 +87,7 @@ use proc_macro::TokenStream;
 /// # Supported argument types
 ///   - `type`: type which implements the [`Module`] trait (required).
 ///   - `name`: ASCII string literal of the name of the kernel module (required).
-///   - `author`: string literal of the author of the kernel module.
+///   - `authors`: array of ASCII string literals of the authors of the kernel module.
 ///   - `description`: string literal of the description of the kernel module.
 ///   - `license`: ASCII string literal of the license of the kernel module (required).
 ///   - `alias`: array of ASCII string literals of the alias names of the kernel module.
@@ -174,6 +173,29 @@ pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
     vtable::vtable(attr, ts)
 }
 
+/// Export a function so that C code can call it via a header file.
+///
+/// Functions exported using this macro can be called from C code using the declaration in the
+/// appropriate header file. It should only be used in cases where C calls the function through a
+/// header file; cases where C calls into Rust via a function pointer in a vtable (such as
+/// `file_operations`) should not use this macro.
+///
+/// This macro has the following effect:
+///
+/// * Disables name mangling for this function.
+/// * Verifies at compile-time that the function signature matches the declaration in the header
+///   file.
+///
+/// You must declare the signature of the Rust function in a header file that is included by
+/// `rust/bindings/bindings_helper.h`.
+///
+/// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently
+/// automatically exported with `EXPORT_SYMBOL_GPL`.
+#[proc_macro_attribute]
+pub fn export(attr: TokenStream, ts: TokenStream) -> TokenStream {
+    export::export(attr, ts)
+}
+
 /// Concatenate two identifiers.
 ///
 /// This is useful in macros that need to declare or reference items with names
@@ -232,106 +254,6 @@ pub fn concat_idents(ts: TokenStream) -> TokenStream {
     concat_idents::concat_idents(ts)
 }
 
-/// Used to specify the pinning information of the fields of a struct.
-///
-/// This is somewhat similar in purpose as
-/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
-/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
-/// field you want to structurally pin.
-///
-/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
-/// then `#[pin]` directs the type of initializer that is required.
-///
-/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
-/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
-/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(lint_reasons)]
-/// # use kernel::prelude::*;
-/// # use std::{sync::Mutex, process::Command};
-/// # use kernel::macros::pin_data;
-/// #[pin_data]
-/// struct DriverData {
-///     #[pin]
-///     queue: Mutex<KVec<Command>>,
-///     buf: KBox<[u8; 1024 * 1024]>,
-/// }
-/// ```
-///
-/// ```
-/// # #![feature(lint_reasons)]
-/// # use kernel::prelude::*;
-/// # use std::{sync::Mutex, process::Command};
-/// # use core::pin::Pin;
-/// # pub struct Info;
-/// # mod bindings {
-/// #     pub unsafe fn destroy_info(_ptr: *mut super::Info) {}
-/// # }
-/// use kernel::macros::{pin_data, pinned_drop};
-///
-/// #[pin_data(PinnedDrop)]
-/// struct DriverData {
-///     #[pin]
-///     queue: Mutex<KVec<Command>>,
-///     buf: KBox<[u8; 1024 * 1024]>,
-///     raw_info: *mut Info,
-/// }
-///
-/// #[pinned_drop]
-/// impl PinnedDrop for DriverData {
-///     fn drop(self: Pin<&mut Self>) {
-///         unsafe { bindings::destroy_info(self.raw_info) };
-///     }
-/// }
-/// # fn main() {}
-/// ```
-///
-/// [`pin_init!`]: ../kernel/macro.pin_init.html
-//  ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
-#[proc_macro_attribute]
-pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
-    pin_data::pin_data(inner, item)
-}
-
-/// Used to implement `PinnedDrop` safely.
-///
-/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(lint_reasons)]
-/// # use kernel::prelude::*;
-/// # use macros::{pin_data, pinned_drop};
-/// # use std::{sync::Mutex, process::Command};
-/// # use core::pin::Pin;
-/// # mod bindings {
-/// #     pub struct Info;
-/// #     pub unsafe fn destroy_info(_ptr: *mut Info) {}
-/// # }
-/// #[pin_data(PinnedDrop)]
-/// struct DriverData {
-///     #[pin]
-///     queue: Mutex<KVec<Command>>,
-///     buf: KBox<[u8; 1024 * 1024]>,
-///     raw_info: *mut bindings::Info,
-/// }
-///
-/// #[pinned_drop]
-/// impl PinnedDrop for DriverData {
-///     fn drop(self: Pin<&mut Self>) {
-///         unsafe { bindings::destroy_info(self.raw_info) };
-///     }
-/// }
-/// ```
-#[proc_macro_attribute]
-pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
-    pinned_drop::pinned_drop(args, input)
-}
-
 /// Paste identifiers together.
 ///
 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
@@ -472,23 +394,29 @@ pub fn paste(input: TokenStream) -> TokenStream {
     tokens.into_iter().collect()
 }
 
-/// Derives the [`Zeroable`] trait for the given struct.
+/// Registers a KUnit test suite and its test cases using a user-space like syntax.
 ///
-/// This can only be used for structs where every field implements the [`Zeroable`] trait.
+/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module
+/// is ignored.
 ///
 /// # Examples
 ///
-/// ```
-/// use kernel::macros::Zeroable;
+/// ```ignore
+/// # use macros::kunit_tests;
+/// #[kunit_tests(kunit_test_suit_name)]
+/// mod tests {
+///     #[test]
+///     fn foo() {
+///         assert_eq!(1, 1);
+///     }
 ///
-/// #[derive(Zeroable)]
-/// pub struct DriverData {
-///     id: i64,
-///     buf_ptr: *mut u8,
-///     len: usize,
+///     #[test]
+///     fn bar() {
+///         assert_eq!(2, 2);
+///     }
 /// }
 /// ```
-#[proc_macro_derive(Zeroable)]
-pub fn derive_zeroable(input: TokenStream) -> TokenStream {
-    zeroable::derive(input)
+#[proc_macro_attribute]
+pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
+    kunit::kunit_tests(attr, ts)
 }