diff options
| -rw-r--r-- | arch/x86/Makefile | 2 | ||||
| -rw-r--r-- | scripts/generate_rust_target.rs | 7 |
2 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 801fd85c3ef6..e8214bff1aeb 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -220,7 +220,7 @@ ifdef CONFIG_MITIGATION_RETPOLINE KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) # Additionally, avoid generating expensive indirect jumps which # are subject to retpolines for small number of switch cases. - # clang turns off jump table generation by default when under + # LLVM turns off jump table generation by default when under # retpoline builds, however, gcc does not for x86. This has # only been fixed starting from gcc stable version 8.4.0 and # onwards, but not for older ones. See gcc bug #86952. diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs index 404edf7587e0..836fdf622c2d 100644 --- a/scripts/generate_rust_target.rs +++ b/scripts/generate_rust_target.rs @@ -164,7 +164,14 @@ fn main() { ); let mut features = "-mmx,+soft-float".to_string(); if cfg.has("MITIGATION_RETPOLINE") { + // The kernel uses `-mretpoline-external-thunk` (for Clang), which Clang maps to the + // target feature of the same name plus the other two target features in + // `clang/lib/Driver/ToolChains/Arch/X86.cpp`. These should be eventually enabled via + // `-Ctarget-feature` when `rustc` starts recognizing them (or via a new dedicated + // flag); see https://github.com/rust-lang/rust/issues/116852. features += ",+retpoline-external-thunk"; + features += ",+retpoline-indirect-branches"; + features += ",+retpoline-indirect-calls"; } ts.push("features", features); ts.push("llvm-target", "x86_64-linux-gnu"); |