diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
index ae203f21cc86..35174d920476 100644
--- a/tools/build/Makefile.build
+++ b/tools/build/Makefile.build
@@ -22,6 +22,9 @@ build-dir := $(srctree)/tools/build
 # Generic definitions
 include $(build-dir)/Build.include
 
+# do not force detected configuration
+-include .config-detected
+
 # Init all relevant variables used in build files so
 # 1) they have correct type
 # 2) they do not inherit any value from the environment
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index cc224080b525..ba414216e506 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -11,6 +11,10 @@ ifneq ($(obj-perf),)
 obj-perf := $(abspath $(obj-perf))/
 endif
 
+$(shell echo -n > .config-detected)
+detected     = $(shell echo "$(1)=y"       >> .config-detected)
+detected_var = $(shell echo "$(1)=$($(1))" >> .config-detected)
+
 LIB_INCLUDE := $(srctree)/tools/lib/
 CFLAGS := $(EXTRA_CFLAGS) $(EXTRA_WARNINGS)