lib/raid6: use CC_FLAGS_FPU for NEON CFLAGS

Now that CC_FLAGS_FPU is exported and can be used anywhere in the source
tree, use it instead of duplicating the flags here.

Link: https://lkml.kernel.org/r/20240329072441.591471-7-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>

Author: SiFiveHolland

lib/raid6/Makefile

@@ -33,25 +33,6 @@ CFLAGS_REMOVE_vpermxor8.o += -msoft-float
 endif
 endif
 
-# 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)
-ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
-NEON_FLAGS := -ffreestanding
-# Enable <arm_neon.h>
-NEON_FLAGS += -isystem $(shell $(CC) -print-file-name=include)
-ifeq ($(ARCH),arm)
-NEON_FLAGS += -march=armv7-a -mfloat-abi=softfp -mfpu=neon
-endif
-CFLAGS_recov_neon_inner.o += $(NEON_FLAGS)
-ifeq ($(ARCH),arm64)
-CFLAGS_REMOVE_recov_neon_inner.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon2.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon4.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon8.o += -mgeneral-regs-only
-endif
-endif
-
 quiet_cmd_unroll = UNROLL  $@
       cmd_unroll = $(AWK) -v N=$* -f $(src)/unroll.awk < $< > $@
 
@@ -75,10 +56,16 @@ targets += vpermxor1.c vpermxor2.c vpermxor4.c vpermxor8.c
 $(obj)/vpermxor%.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
-CFLAGS_neon1.o += $(NEON_FLAGS)
-CFLAGS_neon2.o += $(NEON_FLAGS)
-CFLAGS_neon4.o += $(NEON_FLAGS)
-CFLAGS_neon8.o += $(NEON_FLAGS)
+CFLAGS_neon1.o += $(CC_FLAGS_FPU)
+CFLAGS_neon2.o += $(CC_FLAGS_FPU)
+CFLAGS_neon4.o += $(CC_FLAGS_FPU)
+CFLAGS_neon8.o += $(CC_FLAGS_FPU)
+CFLAGS_recov_neon_inner.o += $(CC_FLAGS_FPU)
+CFLAGS_REMOVE_neon1.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_neon2.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_neon4.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_neon8.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_recov_neon_inner.o += $(CC_FLAGS_NO_FPU)
 targets += neon1.c neon2.c neon4.c neon8.c
 $(obj)/neon%.c: $(src)/neon.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)