kselftest/arm64: mte: Fix compilation with native compiler

stable inclusion
from stable-5.10.36
commit d9a1f62b03da70cba42676b5d8bbf98d008e57a2
bugzilla: 51867
CVE: NA

--------------------------------

[ Upstream commit 4a423645 ]

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
fails:
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: NAndre Przywara <andre.przywara@arm.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Reviewed-by: NMark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-2-andre.przywara@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

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
-endif
 
 #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)