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author | Nathan Chancellor <natechancellor@gmail.com> | 2019-02-02 03:34:36 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-05 22:33:08 +0200 |
commit | d93fe5e6c9d92e3fc4f245422050c91d7f385836 (patch) | |
tree | d5d566d76083a0ab062695b06ba8031c368608a7 /lib/raid6 | |
parent | 3a1ce9793855935a2d2b4d9dc5003d42f797f6fc (diff) | |
download | linux-stable-d93fe5e6c9d92e3fc4f245422050c91d7f385836.tar.gz linux-stable-d93fe5e6c9d92e3fc4f245422050c91d7f385836.tar.bz2 linux-stable-d93fe5e6c9d92e3fc4f245422050c91d7f385836.zip |
ARM: 8833/1: Ensure that NEON code always compiles with Clang
[ Upstream commit de9c0d49d85dc563549972edc5589d195cd5e859 ]
While building arm32 allyesconfig, I ran into the following errors:
arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with
'-mfloat-abi=softfp -mfpu=neon'
In file included from lib/raid6/neon1.c:27:
/home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2:
error: "NEON support not enabled"
Building V=1 showed NEON_FLAGS getting passed along to Clang but
__ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang
only defining __ARM_NEON__ when targeting armv7, rather than armv6k,
which is the '-march' value for allyesconfig.
>From lib/Basic/Targets/ARM.cpp in the Clang source:
// This only gets set when Neon instructions are actually available, unlike
// the VFP define, hence the soft float and arch check. This is subtly
// different from gcc, we follow the intent which was that it should be set
// when Neon instructions are actually available.
if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) {
Builder.defineMacro("__ARM_NEON", "1");
Builder.defineMacro("__ARM_NEON__");
// current AArch32 NEON implementations do not support double-precision
// floating-point even when it is present in VFP.
Builder.defineMacro("__ARM_NEON_FP",
"0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP));
}
Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the
beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets
definined by Clang. This doesn't functionally change anything because
that code will only run where NEON is supported, which is implicitly
armv7.
Link: https://github.com/ClangBuiltLinux/linux/issues/287
Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'lib/raid6')
-rw-r--r-- | lib/raid6/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile index 7ed43eaa02ef..5e0d55c54100 100644 --- a/lib/raid6/Makefile +++ b/lib/raid6/Makefile @@ -40,7 +40,7 @@ endif ifeq ($(CONFIG_KERNEL_MODE_NEON),y) NEON_FLAGS := -ffreestanding ifeq ($(ARCH),arm) -NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon +NEON_FLAGS += -march=armv7-a -mfloat-abi=softfp -mfpu=neon endif CFLAGS_recov_neon_inner.o += $(NEON_FLAGS) ifeq ($(ARCH),arm64) |