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From: Arnd Bergmann <arnd@arndb.de>
To: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org,
	Arnd Bergmann <arnd@arndb.de>,
	Mark Charlebois <charlebm@gmail.com>,
	Behan Webster <behanw@converseincode.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] ARM: pass -march=armv7-a when building NEON files with clang
Date: Mon,  8 Feb 2016 15:25:56 +0100	[thread overview]
Message-ID: <1454941613-2775081-1-git-send-email-arnd@arndb.de> (raw)

clang ignores the -mfpu=neon flag when building with -march=armv6:

In file included from lib/raid6/neon1.c:27:
clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled"

There is no real need to build the file with -march=armv6 in a
multi-CPU enabled kernel, as nothing in here will ever get called
on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only
improve the code quality.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/lib/Makefile | 2 +-
 lib/raid6/Makefile    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 6c7a5b715584..5f6c7eb62cc3 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -39,7 +39,7 @@ $(obj)/csumpartialcopy.o:	$(obj)/csumpartialcopygeneric.S
 $(obj)/csumpartialcopyuser.o:	$(obj)/csumpartialcopygeneric.S
 
 ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
-  NEON_FLAGS			:= -mfloat-abi=softfp -mfpu=neon
+  NEON_FLAGS			:= -mfloat-abi=softfp -mfpu=neon -march=armv7-a
   CFLAGS_xor-neon.o		+= $(NEON_FLAGS)
   obj-$(CONFIG_XOR_BLOCKS)	+= xor-neon.o
 endif
diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile
index 3b10a48fa040..4ef3e800fb39 100644
--- a/lib/raid6/Makefile
+++ b/lib/raid6/Makefile
@@ -23,7 +23,7 @@ endif
 ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
 NEON_FLAGS := -ffreestanding
 ifeq ($(ARCH),arm)
-NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon
+NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon -march=armv7-a
 endif
 ifeq ($(ARCH),arm64)
 CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only
-- 
2.7.0

WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/3] ARM: pass -march=armv7-a when building NEON files with clang
Date: Mon,  8 Feb 2016 15:25:56 +0100	[thread overview]
Message-ID: <1454941613-2775081-1-git-send-email-arnd@arndb.de> (raw)

clang ignores the -mfpu=neon flag when building with -march=armv6:

In file included from lib/raid6/neon1.c:27:
clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled"

There is no real need to build the file with -march=armv6 in a
multi-CPU enabled kernel, as nothing in here will ever get called
on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only
improve the code quality.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/lib/Makefile | 2 +-
 lib/raid6/Makefile    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 6c7a5b715584..5f6c7eb62cc3 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -39,7 +39,7 @@ $(obj)/csumpartialcopy.o:	$(obj)/csumpartialcopygeneric.S
 $(obj)/csumpartialcopyuser.o:	$(obj)/csumpartialcopygeneric.S
 
 ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
-  NEON_FLAGS			:= -mfloat-abi=softfp -mfpu=neon
+  NEON_FLAGS			:= -mfloat-abi=softfp -mfpu=neon -march=armv7-a
   CFLAGS_xor-neon.o		+= $(NEON_FLAGS)
   obj-$(CONFIG_XOR_BLOCKS)	+= xor-neon.o
 endif
diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile
index 3b10a48fa040..4ef3e800fb39 100644
--- a/lib/raid6/Makefile
+++ b/lib/raid6/Makefile
@@ -23,7 +23,7 @@ endif
 ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
 NEON_FLAGS := -ffreestanding
 ifeq ($(ARCH),arm)
-NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon
+NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon -march=armv7-a
 endif
 ifeq ($(ARCH),arm64)
 CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only
-- 
2.7.0

             reply	other threads:[~2016-02-08 14:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-08 14:25 Arnd Bergmann [this message]
2016-02-08 14:25 ` [PATCH 1/3] ARM: pass -march=armv7-a when building NEON files with clang Arnd Bergmann
2016-02-08 14:25 ` [PATCH 2/3] ARM: fix copypage-*.c building " Arnd Bergmann
2016-02-08 14:25   ` Arnd Bergmann
2016-02-08 14:25 ` [PATCH 3/3] ARM: kprobes: use "I" constraint for inline assembly offsets Arnd Bergmann
2016-02-08 14:25   ` Arnd Bergmann

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