From dff64b072708ffef23c117fa1ee1ea59eb417807 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Fri, 2 May 2025 18:45:36 +0900 Subject: rust: Add warn_on macro 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 Reviewed-by: Alice Ryhl 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 --- rust/helpers/bug.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'rust/helpers/bug.c') diff --git a/rust/helpers/bug.c b/rust/helpers/bug.c index e2d13babc737..a62c96f507d1 100644 --- a/rust/helpers/bug.c +++ b/rust/helpers/bug.c @@ -6,3 +6,8 @@ __noreturn void rust_helper_BUG(void) { BUG(); } + +bool rust_helper_WARN_ON(bool cond) +{ + return WARN_ON(cond); +} -- cgit