diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
index c5e2d5f13766..a46ab7b612df 100644
--- a/tools/perf/pmu-events/Build
+++ b/tools/perf/pmu-events/Build
@@ -29,10 +29,12 @@ $(PMU_EVENTS_C): $(EMPTY_PMU_EVENTS_C)
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,gen)cp $< $@
 else
-# Copy checked-in json for generation.
+# Copy checked-in json to OUTPUT for generation if it's an out of source build
+ifneq ($(OUTPUT),)
 $(OUTPUT)pmu-events/arch/%: pmu-events/arch/%
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,gen)cp $< $@
+endif
 
 $(LEGACY_CACHE_JSON): $(LEGACY_CACHE_PY)
 	$(call rule_mkdir)