1 files changed, 13 insertions, 2 deletions

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 64c043b7a438..6b5452a120af 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -70,8 +70,9 @@ ifneq ($(OUTPUT),)
 #$(info Determined 'OUTPUT' to be $(OUTPUT))
 endif
 
-$(OUTPUT)PERF-VERSION-FILE: .FORCE-PERF-VERSION-FILE
+$(OUTPUT)PERF-VERSION-FILE: ../../.git/HEAD
         @$(SHELL_PATH) util/PERF-VERSION-GEN $(OUTPUT)
+        @touch $(OUTPUT)PERF-VERSION-FILE
 
 CC = $(CROSS_COMPILE)gcc
 AR = $(CROSS_COMPILE)ar
@@ -814,6 +815,16 @@ clean: $(LIBTRACEEVENT)-clean $(LIBLK)-clean
         $(RM) $(OUTPUT)util/*-flex*
         $(python-clean)
 
+#
+# Trick: if ../../.git does not exist - we are building out of tree for example,
+# then force version regeneration:
+#
+ifeq ($(wildcard ../../.git/HEAD),)
+    GIT-HEAD-PHONY = ../../.git/HEAD
+else
+    GIT-HEAD-PHONY =
+endif
+
 .PHONY: all install clean strip $(LIBTRACEEVENT) $(LIBLK)
 .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
-.PHONY: .FORCE-PERF-VERSION-FILE TAGS tags cscope .FORCE-PERF-CFLAGS
+.PHONY: $(GIT-HEAD-PHONY) TAGS tags cscope .FORCE-PERF-CFLAGS