6.12-stable review patch. If anyone has any objections, please let me know.
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From: Conor Dooley conor.dooley@microchip.com
commit 812258ff4166bcd41c7d44707e0591f9ae32ac8c upstream.
The kernel uses the standard rustc targets for non-x86 targets, and out of those only 64-bit arm's target has kcfi support enabled. For x86, the custom 64-bit target enables kcfi.
The HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC config option that allows CFI_CLANG to be used in combination with RUST does not check whether the rustc target supports kcfi. This breaks the build on riscv (and presumably 32-bit arm) when CFI_CLANG and RUST are enabled at the same time.
Ordinarily, a rustc-option check would be used to detect target support but unfortunately rustc-option filters out the target for reasons given in commit 46e24a545cdb4 ("rust: kasan/kbuild: fix missing flags on first build"). As a result, if the host supports kcfi but the target does not, e.g. when building for riscv on x86_64, the build would remain broken.
Instead, make HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC depend on the only two architectures where the target used supports it to fix the build.
CC: stable@vger.kernel.org Fixes: ca627e636551e ("rust: cfi: add support for CFI_CLANG with Rust") Signed-off-by: Conor Dooley conor.dooley@microchip.com Acked-by: Miguel Ojeda ojeda@kernel.org Reviewed-by: Alice Ryhl aliceryhl@google.com Link: https://lore.kernel.org/r/20250908-distill-lint-1ae78bcf777c@spud Signed-off-by: Paul Walmsley pjw@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/Kconfig | 1 + 1 file changed, 1 insertion(+)
--- a/arch/Kconfig +++ b/arch/Kconfig @@ -861,6 +861,7 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS def_bool y depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG depends on RUSTC_VERSION >= 107900 + depends on ARM64 || X86_64 # With GCOV/KASAN we need this fix: https://github.com/rust-lang/rust/pull/129373 depends on (RUSTC_LLVM_VERSION >= 190103 && RUSTC_VERSION >= 108200) || \ (!GCOV_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS)