From: Conor Dooley conor.dooley@microchip.com
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 --- CC: Paul Walmsley paul.walmsley@sifive.com CC: Palmer Dabbelt palmer@dabbelt.com CC: Alexandre Ghiti alex@ghiti.fr CC: Miguel Ojeda ojeda@kernel.org CC: Alex Gaynor alex.gaynor@gmail.com CC: Boqun Feng boqun.feng@gmail.com CC: Gary Guo gary@garyguo.net CC: "Björn Roy Baron" bjorn3_gh@protonmail.com CC: Benno Lossin lossin@kernel.org CC: Andreas Hindborg a.hindborg@kernel.org CC: Alice Ryhl aliceryhl@google.com CC: Trevor Gross tmgross@umich.edu CC: Danilo Krummrich dakr@kernel.org CC: Kees Cook kees@kernel.org CC: Sami Tolvanen samitolvanen@google.com CC: Matthew Maurer mmaurer@google.com CC: "Peter Zijlstra (Intel)" peterz@infradead.org CC: linux-kernel@vger.kernel.org CC: linux-riscv@lists.infradead.org CC: rust-for-linux@vger.kernel.org --- arch/Kconfig | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/Kconfig b/arch/Kconfig index d1b4ffd6e0856..880cddff5eda7 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -917,6 +917,7 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 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)