From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Date: Fri, 11 Oct 2019 03:27:58 +0300
Subject: samples/bpf: Use __LINUX_ARM_ARCH__ selector for arm
Patch-mainline: v5.5-rc1
Git-commit: 0e865aedad571b93b2d8bb780f17befd5ee4b308
References: bsc#1177028

For arm, -D__LINUX_ARM_ARCH__=X is min version used as instruction
set selector and is absolutely required while parsing some parts of
headers. It's present in KBUILD_CFLAGS but not in autoconf.h, so let's
retrieve it from and add to programs cflags. In another case errors
like "SMP is not supported" for armv7 and bunch of other errors are
issued resulting to incorrect final object.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191011002808.28206-6-ivan.khoronzhuk@linaro.org
Acked-by: Gary Lin <glin@suse.com>
---
 samples/bpf/Makefile |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -186,6 +186,14 @@ HOSTLDLIBS_map_perf_test	+= -lrt
 HOSTLDLIBS_test_overhead	+= -lrt
 HOSTLDLIBS_xdpsock		+= -pthread
 
+ifeq ($(ARCH), arm)
+# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
+# headers when arm instruction set identification is requested.
+ARM_ARCH_SELECTOR := $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS))
+BPF_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
+KBUILD_HOSTCFLAGS += $(ARM_ARCH_SELECTOR)
+endif
+
 # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
 #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
 LLC ?= llc