kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/Documentation/doc-guide/checktransupdate.rst b/Documentation/doc-guide/checktransupdate.rst
new file mode 100644
index 000000000..7b25375cc
--- /dev/null
+++ b/Documentation/doc-guide/checktransupdate.rst
@@ -0,0 +1,54 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Checking for needed translation updates
+=======================================
+
+This script helps track the translation status of the documentation in
+different locales, i.e., whether the documentation is up-to-date with
+the English counterpart.
+
+How it works
+------------
+
+It uses ``git log`` command to track the latest English commit from the
+translation commit (order by author date) and the latest English commits
+from HEAD. If any differences occur, the file is considered as out-of-date,
+then commits that need to be updated will be collected and reported.
+
+Features implemented
+
+-  check all files in a certain locale
+-  check a single file or a set of files
+-  provide options to change output format
+-  track the translation status of files that have no translation
+
+Usage
+-----
+
+::
+
+   tools/docs/checktransupdate.py --help
+
+Please refer to the output of argument parser for usage details.
+
+Samples
+
+-  ``tools/docs/checktransupdate.py -l zh_CN``
+   This will print all the files that need to be updated in the zh_CN locale.
+-  ``tools/docs/checktransupdate.py Documentation/translations/zh_CN/dev-tools/testing-overview.rst``
+   This will only print the status of the specified file.
+
+Then the output is something like:
+
+::
+
+    Documentation/dev-tools/kfence.rst
+    No translation in the locale of zh_CN
+
+    Documentation/translations/zh_CN/dev-tools/testing-overview.rst
+    commit 42fb9cfd5b18 ("Documentation: dev-tools: Add link to RV docs")
+    1 commits needs resolving in total
+
+Features to be implemented
+
+- files can be a folder instead of only a file