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`
  ...

Author: torvalds

Documentation/rust/coding-guidelines.rst

@@ -373,3 +373,11 @@ triggered due to non-local changes (such as ``dead_code``).
 For more information about diagnostics in Rust, please see:
 
 	https://doc.rust-lang.org/stable/reference/attributes/diagnostics.html
+
+Error handling
+--------------
+
+For some background and guidelines about Rust for Linux specific error handling,
+please see:
+
+	https://rust.docs.kernel.org/kernel/error/type.Result.html#error-codes-in-c-and-rust

Documentation/rust/testing.rst

@@ -123,6 +123,13 @@ A current limitation is that KUnit does not support assertions in other tasks.
 Thus, we presently simply print an error to the kernel log if an assertion
 actually failed. Additionally, doctests are not run for nonpublic functions.
 
+Since these tests are examples, i.e. they are part of the documentation, they
+should generally be written like "real code". Thus, for example, instead of
+using ``unwrap()`` or ``expect()``, use the ``?`` operator. For more background,
+please see:
+
+	https://rust.docs.kernel.org/kernel/error/type.Result.html#error-codes-in-c-and-rust
+
 The ``#[test]`` tests
 ---------------------
 

MAINTAINERS

@@ -6981,6 +6981,19 @@ F:	include/linux/dma-mapping.h
 F:	include/linux/swiotlb.h
 F:	kernel/dma/
 
+DMA MAPPING HELPERS DEVICE DRIVER API [RUST]
+M:	Abdiel Janulgue <abdiel.janulgue@gmail.com>
+M:	Danilo Krummrich <dakr@kernel.org>
+R:	Daniel Almeida <daniel.almeida@collabora.com>
+R:	Robin Murphy <robin.murphy@arm.com>
+R:	Andreas Hindborg <a.hindborg@kernel.org>
+L:	rust-for-linux@vger.kernel.org
+S:	Supported
+W:	https://rust-for-linux.com
+T:	git https://github.com/Rust-for-Linux/linux.git alloc-next
+F:	rust/kernel/dma.rs
+F:	samples/rust/rust_dma.rs
+
 DMA-BUF HEAPS FRAMEWORK
 M:	Sumit Semwal <sumit.semwal@linaro.org>
 R:	Benjamin Gaignard <benjamin.gaignard@collabora.com>
@@ -10539,6 +10552,21 @@ F:	kernel/time/timer_list.c
 F:	kernel/time/timer_migration.*
 F:	tools/testing/selftests/timers/
 
+HIGH-RESOLUTION TIMERS [RUST]
+M:	Andreas Hindborg <a.hindborg@kernel.org>
+R:	Boqun Feng <boqun.feng@gmail.com>
+R:	Frederic Weisbecker <frederic@kernel.org>
+R:	Lyude Paul <lyude@redhat.com>
+R:	Thomas Gleixner <tglx@linutronix.de>
+R:	Anna-Maria Behnsen <anna-maria@linutronix.de>
+L:	rust-for-linux@vger.kernel.org
+S:	Supported
+W:	https://rust-for-linux.com
+B:	https://github.com/Rust-for-Linux/linux/issues
+T:	git https://github.com/Rust-for-Linux/linux.git hrtimer-next
+F:	rust/kernel/time/hrtimer.rs
+F:	rust/kernel/time/hrtimer/
+
 HIGH-SPEED SCC DRIVER FOR AX.25
 L:	linux-hams@vger.kernel.org
 S:	Orphan
@@ -12902,6 +12930,7 @@ F:	Documentation/dev-tools/kunit/
 F:	include/kunit/
 F:	lib/kunit/
 F:	rust/kernel/kunit.rs
+F:	rust/macros/kunit.rs
 F:	scripts/rustdoc_test_*
 F:	tools/testing/kunit/
 
@@ -20993,6 +21022,7 @@ R:	Benno Lossin <benno.lossin@proton.me>
 R:	Andreas Hindborg <a.hindborg@kernel.org>
 R:	Alice Ryhl <aliceryhl@google.com>
 R:	Trevor Gross <tmgross@umich.edu>
+R:	Danilo Krummrich <dakr@kernel.org>
 L:	rust-for-linux@vger.kernel.org
 S:	Supported
 W:	https://rust-for-linux.com
@@ -21013,9 +21043,23 @@ RUST [ALLOC]
 M:	Danilo Krummrich <dakr@kernel.org>
 L:	rust-for-linux@vger.kernel.org
 S:	Maintained
+T:	git https://github.com/Rust-for-Linux/linux.git alloc-next
 F:	rust/kernel/alloc.rs
 F:	rust/kernel/alloc/
 
+RUST [PIN-INIT]
+M:	Benno Lossin <benno.lossin@proton.me>
+L:	rust-for-linux@vger.kernel.org
+S:	Maintained
+W:	https://rust-for-linux.com/pin-init
+B:	https://github.com/Rust-for-Linux/pin-init/issues
+C:	zulip://rust-for-linux.zulipchat.com
+P:	rust/pin-init/CONTRIBUTING.md
+T:	git https://github.com/Rust-for-Linux/linux.git pin-init-next
+F:	rust/kernel/init.rs
+F:	rust/pin-init/
+K:	\bpin-init\b|pin_init\b|PinInit
+
 RXRPC SOCKETS (AF_RXRPC)
 M:	David Howells <dhowells@redhat.com>
 M:	Marc Dionne <marc.dionne@auristor.com>

drivers/block/rnull.rs

@@ -27,7 +27,7 @@ use kernel::{
 module! {
     type: NullBlkModule,
     name: "rnull_mod",
-    author: "Andreas Hindborg",
+    authors: ["Andreas Hindborg"],
     description: "Rust implementation of the C null block driver",
     license: "GPL v2",
 }

drivers/gpu/drm/drm_panic.c

@@ -486,11 +486,6 @@ static void drm_panic_qr_exit(void)
 	stream.workspace = NULL;
 }
 
-extern size_t drm_panic_qr_max_data_size(u8 version, size_t url_len);
-
-extern u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size,
-				u8 *tmp, size_t tmp_size);
-
 static int drm_panic_get_qr_code_url(u8 **qr_image)
 {
 	struct kmsg_dump_iter iter;

drivers/gpu/drm/drm_panic_qr.rs

@@ -27,7 +27,7 @@
 //! * <https://github.com/erwanvivien/fast_qr>
 //! * <https://github.com/bjguillot/qr>
 
-use kernel::str::CStr;
+use kernel::{prelude::*, str::CStr};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd)]
 struct Version(usize);
@@ -891,7 +891,7 @@ impl QrImage<'_> {
 /// * `tmp` must be valid for reading and writing for `tmp_size` bytes.
 ///
 /// They must remain valid for the duration of the function call.
-#[no_mangle]
+#[export]
 pub unsafe extern "C" fn drm_panic_qr_generate(
     url: *const kernel::ffi::c_char,
     data: *mut u8,
@@ -942,8 +942,13 @@ pub unsafe extern "C" fn drm_panic_qr_generate(
 /// * If `url_len` > 0, remove the 2 segments header/length and also count the
 ///   conversion to numeric segments.
 /// * If `url_len` = 0, only removes 3 bytes for 1 binary segment.
-#[no_mangle]
-pub extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize {
+///
+/// # Safety
+///
+/// Always safe to call.
+// Required to be unsafe due to the `#[export]` annotation.
+#[export]
+pub unsafe extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize {
     #[expect(clippy::manual_range_contains)]
     if version < 1 || version > 40 {
         return 0;

drivers/net/phy/ax88796b_rust.rs

@@ -19,7 +19,7 @@ kernel::module_phy_driver! {
         DeviceId::new_with_driver::<PhyAX88796B>()
     ],
     name: "rust_asix_phy",
-    author: "FUJITA Tomonori <fujita.tomonori@gmail.com>",
+    authors: ["FUJITA Tomonori <fujita.tomonori@gmail.com>"],
     description: "Rust Asix PHYs driver",
     license: "GPL",
 }

drivers/net/phy/qt2025.rs

@@ -26,7 +26,7 @@ kernel::module_phy_driver! {
         phy::DeviceId::new_with_driver::<PhyQT2025>(),
     ],
     name: "qt2025_phy",
-    author: "FUJITA Tomonori <fujita.tomonori@gmail.com>",
+    authors: ["FUJITA Tomonori <fujita.tomonori@gmail.com>"],
     description: "AMCC QT2025 PHY driver",
     license: "GPL",
     firmware: ["qt2025-2.0.3.3.fw"],

include/drm/drm_panic.h

@@ -163,4 +163,11 @@ static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags)
 
 #endif
 
+#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
+size_t drm_panic_qr_max_data_size(u8 version, size_t url_len);
+
+u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size,
+			 u8 *tmp, size_t tmp_size);
+#endif
+
 #endif /* __DRM_PANIC_H__ */

include/linux/sprintf.h

@@ -24,4 +24,7 @@ __scanf(2, 0) int vsscanf(const char *, const char *, va_list);
 extern bool no_hash_pointers;
 int no_hash_pointers_enable(char *str);
 
+/* Used for Rust formatting ('%pA') */
+char *rust_fmt_argument(char *buf, char *end, const void *ptr);
+
 #endif	/* _LINUX_KERNEL_SPRINTF_H */