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, 47 insertions, 10 deletions

diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index bb96ca0f774b..169f67773518 100644
--- a/Documentation/process/changes.rst
+++ b/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)        1.73.0           rustc --version
+Rust (optional)        1.74.1           rustc --version
 bindgen (optional)     0.65.1           bindgen --version
 GNU make               3.82             make --version
 bash                   4.2              bash --version
diff --git a/Documentation/rust/coding-guidelines.rst b/Documentation/rust/coding-guidelines.rst
index aa8ed082613e..05542840b16c 100644
--- a/Documentation/rust/coding-guidelines.rst
+++ b/Documentation/rust/coding-guidelines.rst
@@ -177,6 +177,19 @@ please take a look at the ``rustdoc`` book at:
 
 	https://doc.rust-lang.org/rustdoc/how-to-write-documentation.html
 
+In addition, the kernel supports creating links relative to the source tree by
+prefixing the link destination with ``srctree/``. For instance:
+
+.. code-block:: rust
+
+	//! C header: [`include/linux/printk.h`](srctree/include/linux/printk.h)
+
+or:
+
+.. code-block:: rust
+
+	/// [`struct mutex`]: srctree/include/linux/mutex.h
+
 
 Naming
 ------
diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
index 081397827a7e..236c6dd3c647 100644
--- a/Documentation/rust/general-information.rst
+++ b/Documentation/rust/general-information.rst
@@ -77,3 +77,27 @@ configuration:
 	#[cfg(CONFIG_X="y")]   // Enabled as a built-in (`y`)
 	#[cfg(CONFIG_X="m")]   // Enabled as a module   (`m`)
 	#[cfg(not(CONFIG_X))]  // Disabled
+
+
+Testing
+-------
+
+There are the tests that come from the examples in the Rust documentation
+and get transformed into KUnit tests. These can be run via KUnit. For example
+via ``kunit_tool`` (``kunit.py``) on the command line::
+
+	./tools/testing/kunit/kunit.py run --make_options LLVM=1 --arch x86_64 --kconfig_add CONFIG_RUST=y
+
+Alternatively, KUnit can run them as kernel built-in at boot. Refer to
+Documentation/dev-tools/kunit/index.rst for the general KUnit documentation
+and Documentation/dev-tools/kunit/architecture.rst for the details of kernel
+built-in vs. command line testing.
+
+Additionally, there are the ``#[test]`` tests. These can be run using
+the ``rusttest`` Make target::
+
+	make LLVM=1 rusttest
+
+This requires the kernel ``.config`` and downloads external repositories.
+It runs the ``#[test]`` tests on the host (currently) and thus is fairly
+limited in what these tests can test.
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
index f382914f4191..cc3f11e0d441 100644
--- a/Documentation/rust/quick-start.rst
+++ b/Documentation/rust/quick-start.rst
@@ -33,14 +33,18 @@ A particular version of the Rust compiler is required. Newer versions may or
 may not work because, for the moment, the kernel depends on some unstable
 Rust features.
 
-If ``rustup`` is being used, enter the checked out source code directory
-and run::
+If ``rustup`` is being used, enter the kernel build directory (or use
+``--path=<build-dir>`` argument to the ``set`` sub-command) and run::
 
 	rustup override set $(scripts/min-tool-version.sh rustc)
 
 This will configure your working directory to use the correct version of
-``rustc`` without affecting your default toolchain. If you are not using
-``rustup``, fetch a standalone installer from:
+``rustc`` without affecting your default toolchain.
+
+Note that the override applies to the current working directory (and its
+sub-directories).
+
+If you are not using ``rustup``, fetch a standalone installer from:
 
 	https://forge.rust-lang.org/infra/other-installation-methods.html#standalone
 
@@ -76,7 +80,7 @@ libclang
 
 ``libclang`` (part of LLVM) is used by ``bindgen`` to understand the C code
 in the kernel, which means LLVM needs to be installed; like when the kernel
-is compiled with ``CC=clang`` or ``LLVM=1``.
+is compiled with ``LLVM=1``.
 
 Linux distributions are likely to have a suitable one available, so it is
 best to check that first.
@@ -229,10 +233,6 @@ at the moment. That is::
 
 	make LLVM=1
 
-For architectures that do not support a full LLVM toolchain, use::
-
-	make CC=clang
-
 Using GCC also works for some configurations, but it is very experimental at
 the moment.