Messages in this thread | | | Date | Mon, 20 Mar 2023 13:19:35 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH AUTOSEL 4.14 2/5] rust: arch/um: Disable FP/SIMD instruction to match x86 |
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Hi!
> [ Upstream commit 8849818679478933dd1d9718741f4daa3f4e8b86 ] > > The kernel disables all SSE and similar FP/SIMD instructions on > x86-based architectures (partly because we shouldn't be using floats in > the kernel, and partly to avoid the need for stack alignment, see: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 ) > > UML does not do the same thing, which isn't in itself a problem, but > does add to the list of differences between UML and "normal" x86 builds. > > In addition, there was a crash bug with LLVM < 15 / rustc < 1.65 when > building with SSE, so disabling it fixes rust builds with earlier > compiler versions, see: > https://github.com/Rust-for-Linux/linux/pull/881
We don't have rust in 4.14, so cited problem can't hit us. This should not go to -stable.
(Plus, KBUILD_RUSTFLAGS is not going to exist in -stable).
Best regards, Pavel
> +# Disable SSE and other FP/SIMD instructions to match normal x86 > +# > +KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx > +KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 > + > ifeq ($(CONFIG_X86_32),y) > START := 0x8048000 >
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