Commit b0b8a15b authored by Samuel Holland's avatar Samuel Holland Committed by Andrew Morton
Browse files

x86: implement ARCH_HAS_KERNEL_FPU_SUPPORT 

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: default avatarSamuel Holland <samuel.holland@sifive.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: WANG Xuerui <git@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 01db473e

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ config X86 
	select ARCH_HAS_FORTIFY_SOURCE

	select ARCH_HAS_GCOV_PROFILE_ALL

	select ARCH_HAS_KCOV			if X86_64

	select ARCH_HAS_KERNEL_FPU_SUPPORT

	select ARCH_HAS_MEM_ENCRYPT

	select ARCH_HAS_MEMBARRIER_SYNC_CORE

	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS

arch/x86/Makefile

+20 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/include/asm/fpu.h

0 → 100644
+13 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright (C) 2023 SiFive

 */



#ifndef _ASM_X86_FPU_H

#define _ASM_X86_FPU_H



#include <asm/fpu/api.h>



#define kernel_fpu_available()	true



#endif /* ! _ASM_X86_FPU_H */