diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 91470449516694369b00838d23e393b133ed061f..4835618a5608892054de87d497e45e644fdeb0da 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -37,12 +37,25 @@ ifneq ($(O),)
   FULL_O := $(shell readlink -f $(O) || echo $(O))
 endif
 
+#
+# Only accept the 'DEBUG' variable from the command line:
+#
+ifeq ("$(origin DEBUG)", "command line")
+  ifeq ($(DEBUG),)
+    override DEBUG = 0
+  else
+    SET_DEBUG = "DEBUG=$(DEBUG)"
+  endif
+else
+  override DEBUG = 0
+endif
+
 define print_msg
   @printf '  BUILD:   Doing '\''make \033[33m-j'$(JOBS)'\033[m'\'' parallel build\n'
 endef
 
 define make
-  @$(MAKE) -f Makefile.perf --no-print-directory -j$(JOBS) O=$(FULL_O) $@
+  @$(MAKE) -f Makefile.perf --no-print-directory -j$(JOBS) O=$(FULL_O) $(SET_DEBUG) $@
 endef
 
 #
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index 96804247df088cd40eb3fab2b7d31811f7486458..9524c0c4e88fdb53545df18415392f16c65d2a1b 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -66,10 +66,7 @@ ifneq ($(WERROR),0)
   CFLAGS += -Werror
 endif
 
-ifeq ("$(origin DEBUG)", "command line")
-  PERF_DEBUG = $(DEBUG)
-endif
-ifndef PERF_DEBUG
+ifeq ($(DEBUG),0)
   CFLAGS += -O6
 endif
 
@@ -210,7 +207,7 @@ ifeq ($(feature-volatile-register-var), 1)
   CFLAGS += -Wvolatile-register-var
 endif
 
-ifndef PERF_DEBUG
+ifeq ($(DEBUG),0)
   ifeq ($(feature-fortify-source), 1)
     CFLAGS += -D_FORTIFY_SOURCE=2
   endif