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arm64: implement ARCH_HAS_KERNEL_FPU_SUPPORT

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arm64 provides an equivalent to the common kernel-mode FPU API, but in a
different header and using different function names.  Add a wrapper
header, and export CFLAGS adjustments as found in lib/raid6/Makefile.

Link: https://lkml.kernel.org/r/20240329072441.591471-5-samuel.holland@sifive.com
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Samuel Holland 2024-03-29 00:18:19 -07:00 committed by Andrew Morton
parent c41624315b
commit 71883ae352
3 changed files with 24 additions and 1 deletions
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1
arch/arm64/Kconfig
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@ -30,6 +30,7 @@ config ARM64
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS

9
arch/arm64/Makefile
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@ -36,7 +36,14 @@ ifeq ($(CONFIG_BROKEN_GAS_INST),y)
$(warning Detected assembler with broken .inst; disassembly will be unreliable)
endif
KBUILD_CFLAGS += -mgeneral-regs-only \
# The GCC option -ffreestanding is required in order to compile code containing
# ARM/NEON intrinsics in a non C99-compliant environment (such as the kernel)
CC_FLAGS_FPU := -ffreestanding
# Enable <arm_neon.h>
CC_FLAGS_FPU += -isystem $(shell $(CC) -print-file-name=include)
CC_FLAGS_NO_FPU := -mgeneral-regs-only
KBUILD_CFLAGS += $(CC_FLAGS_NO_FPU) \
$(compat_vdso) $(cc_has_k_constraint)
KBUILD_CFLAGS += $(call cc-disable-warning, psabi)
KBUILD_AFLAGS += $(compat_vdso)

15
arch/arm64/include/asm/fpu.h Normal file
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@ -0,0 +1,15 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2023 SiFive
*/
#ifndef __ASM_FPU_H
#define __ASM_FPU_H
#include <asm/neon.h>
#define kernel_fpu_available() cpu_has_neon()
#define kernel_fpu_begin() kernel_neon_begin()
#define kernel_fpu_end() kernel_neon_end()
#endif /* ! __ASM_FPU_H */