[PATCH 19/59] perf build: Use FEATURE-DUMP in bpf subproject

[Arnaldo Carvalho de Melo]

From: Jiri Olsa <jolsa@xxxxxxxxxx>

Using FEATURE-DUMP in bpf subproject for features detection in case bpf
is built via perf. Keeping the current features detection otherwise.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama <pi3orama@xxxxxxx>
Link: http://lkml.kernel.org/r/1450893514-9158-6-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/lib/bpf/Makefile   | 4 ++++
 tools/perf/Makefile.perf | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 636e3ddb93a1..919b71780710 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -80,7 +80,11 @@ endif
 endif
 
 ifeq ($(check_feat),1)
+ifeq ($(FEATURES_DUMP),)
 include $(srctree)/tools/build/Makefile.feature
+else
+include $(FEATURES_DUMP)
+endif
 endif
 
 export prefix libdir src obj
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 569fcf022531..404e3b1c4e31 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -436,7 +436,7 @@ $(LIBAPI)-clean:
 	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null
 
 $(LIBBPF): fixdep FORCE
-	$(Q)$(MAKE) -C $(BPF_DIR) O=$(OUTPUT) $(OUTPUT)libbpf.a
+	$(Q)$(MAKE) -C $(BPF_DIR) O=$(OUTPUT) $(OUTPUT)libbpf.a FEATURES_DUMP=$(realpath $(OUTPUT)FEATURE-DUMP)
 
 $(LIBBPF)-clean:
 	$(call QUIET_CLEAN, libbpf)
-- 
2.1.0