FUJITA Tomonori
dff64b0727
Add warn_on macro, uses the BUG/WARN feature (lib/bug.c) via assembly for x86_64/arm64/riscv. The current Rust code simply wraps BUG() macro but doesn't provide the proper debug information. The BUG/WARN feature can only be used from assembly. This uses the assembly code exported by the C side via ARCH_WARN_ASM macro. To avoid duplicating the assembly code, this approach follows the same strategy as the static branch code: it generates the assembly code for Rust using the C preprocessor at compile time. Similarly, ARCH_WARN_REACHABLE is also used at compile time to generate the assembly code; objtool's reachable annotation code. It's used for only architectures that use objtool. For now, Loongarch and arm just use a wrapper for WARN macro. UML doesn't use the assembly BUG/WARN feature; just wrapping generic BUG/WARN functions implemented in C works. Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250502094537.231725-5-fujita.tomonori@gmail.com [ Avoid evaluating the condition twice (a good idea in general, but it also matches the C side). Simplify with `as_char_ptr()` to avoid a cast. Cast to `ffi` integer types for `warn_slowpath_fmt`. Avoid cast for `null()`. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.