From b0b8a15bb89e09e12aa6be8ae28128bb656338f1 Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Fri, 29 Mar 2024 00:18:25 -0700 Subject: x86: implement ARCH_HAS_KERNEL_FPU_SUPPORT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit x86 already provides kernel_fpu_begin() and kernel_fpu_end(), but in a different header. Add a wrapper header, and export the CFLAGS adjustments as found in lib/Makefile. Link: https://lkml.kernel.org/r/20240329072441.591471-11-samuel.holland@sifive.com Signed-off-by: Samuel Holland Reviewed-by: Christoph Hellwig Acked-by: Christian König Cc: Alex Deucher Cc: Borislav Petkov (AMD) Cc: Catalin Marinas Cc: Dave Hansen Cc: Huacai Chen Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Michael Ellerman Cc: Nathan Chancellor Cc: Nicolas Schier Cc: Palmer Dabbelt Cc: Russell King Cc: Thomas Gleixner Cc: WANG Xuerui Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/x86/Makefile | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'arch/x86/Makefile') diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 5ab93fcdd691..164498b3382a 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -74,6 +74,26 @@ KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 +# +# CFLAGS for compiling floating point code inside the kernel. +# +CC_FLAGS_FPU := -msse -msse2 +ifdef CONFIG_CC_IS_GCC +# Stack alignment mismatch, proceed with caution. +# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3 +# (8B stack alignment). +# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 +# +# The "-msse" in the first argument is there so that the +# -mpreferred-stack-boundary=3 build error: +# +# -mpreferred-stack-boundary=3 is not between 4 and 12 +# +# can be triggered. Otherwise gcc doesn't complain. +CC_FLAGS_FPU += -mhard-float +CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4) +endif + ifeq ($(CONFIG_X86_KERNEL_IBT),y) # # Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate -- cgit v1.2.3