[PATCH 5.12 085/384] kselftest/arm64: mte: Fix compilation with native compiler

From: Greg Kroah-Hartman
Date: Mon May 10 2021 - 08:50:59 EST

From: Andre Przywara <andre.przywara@xxxxxxx>

[ Upstream commit 4a423645bc2690376a7a94b4bb7b2f74bc6206ff ]

The mte selftest Makefile contains a check for GCC, to add the memtag
-march flag to the compiler options. This check fails if the compiler
is not explicitly specified, so reverts to the standard "cc", in which
case --version doesn't mention the "gcc" string we match against:
$ cc --version | head -n 1
cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0

This will not add the -march switch to the command line, so compilation
mte_helper.S: Assembler messages:
mte_helper.S:25: Error: selected processor does not support `irg x0,x0,xzr'
mte_helper.S:38: Error: selected processor does not support `gmi x1,x0,xzr'

Actually clang accepts the same -march option as well, so we can just
drop this check and add this unconditionally to the command line, to avoid
any future issues with this check altogether (gcc actually prints
basename(argv[0]) when called with --version).

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reviewed-by: Mark Brown <broone@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210319165334.29213-2-andre.przywara@xxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
tools/testing/selftests/arm64/mte/Makefile | 2 --
1 file changed, 2 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 0b3af552632a..df15d44aeb8d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -6,9 +6,7 @@ SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
PROGS := $(patsubst %.c,%,$(SRCS))

#Add mte compiler option
-ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
CFLAGS += -march=armv8.5-a+memtag

#check if the compiler works well
mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)