6.13-stable review patch. If anyone has any objections, please let me know.
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From: Miguel Ojeda ojeda@kernel.org
commit 446a8351f160d65a1c5df7097f31c74102ed2bb1 upstream.
Starting with Rust 1.85.0 (to be released 2025-02-20), `rustc` warns [1] about disabling neon in the aarch64 hardfloat target:
warning: target feature `neon` cannot be toggled with `-Ctarget-feature`: unsound on hard-float targets because it changes float ABI | = note: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #116344 https://github.com/rust-lang/rust/issues/116344
Thus, instead, use the softfloat target instead.
While trying it out, I found that the kernel sanitizers were not enabled for that built-in target [2]. Upstream Rust agreed to backport the enablement for the current beta so that it is ready for the 1.85.0 release [3] -- thanks!
However, that still means that before Rust 1.85.0, we cannot switch since sanitizers could be in use. Thus conditionally do so.
Cc: stable@vger.kernel.org # Needed in 6.12.y and 6.13.y only (Rust is pinned in older LTSs). Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Matthew Maurer mmaurer@google.com Cc: Alice Ryhl aliceryhl@google.com Cc: Ralf Jung post@ralfj.de Cc: Jubilee Young workingjubilee@gmail.com Link: https://github.com/rust-lang/rust/pull/133417 [1] Link: https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/arm6... [2] Link: https://github.com/rust-lang/rust/pull/135905 [3] Link: https://github.com/rust-lang/rust/issues/116344 Signed-off-by: Miguel Ojeda ojeda@kernel.org Reviewed-by: Trevor Gross tmgross@umich.edu Tested-by: Matthew Maurer mmaurer@google.com Reviewed-by: Ralf Jung post@ralfj.de Reviewed-by: Alice Ryhl aliceryhl@google.com Link: https://lore.kernel.org/r/20250210163732.281786-1-ojeda@kernel.org Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/Makefile | 4 ++++ 1 file changed, 4 insertions(+)
--- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -48,7 +48,11 @@ KBUILD_CFLAGS += $(CC_FLAGS_NO_FPU) \ KBUILD_CFLAGS += $(call cc-disable-warning, psabi) KBUILD_AFLAGS += $(compat_vdso)
+ifeq ($(call test-ge, $(CONFIG_RUSTC_VERSION), 108500),y) +KBUILD_RUSTFLAGS += --target=aarch64-unknown-none-softfloat +else KBUILD_RUSTFLAGS += --target=aarch64-unknown-none -Ctarget-feature="-neon" +endif
KBUILD_CFLAGS += $(call cc-option,-mabi=lp64) KBUILD_AFLAGS += $(call cc-option,-mabi=lp64)