diff --git a/mk/pp.mk b/mk/pp.mk
index e9273c33b9d..bbcb9018f95 100644
--- a/mk/pp.mk
+++ b/mk/pp.mk
@@ -1,11 +1,15 @@
+# Create a way to reformat just some files
+ifdef PPFILES
+  PP_INPUTS_FILTERED := $(wildcard $(PPFILES))
+else
+  PP_INPUTS = $(wildcard $(addprefix $(S)src/lib/,*.rs */*.rs)) \
+              $(wildcard $(addprefix $(S)src/comp/,*.rs */*.rs */*/*.rs)) \
+              $(wildcard $(S)src/test/*/*.rs   \
+                         $(S)src/test/*/*/*.rs) \
+              $(wildcard $(S)src/fuzzer/*.rs)
 
-PP_INPUTS = $(wildcard $(addprefix $(S)src/lib/,*.rs */*.rs)) \
-            $(wildcard $(addprefix $(S)src/comp/,*.rs */*.rs */*/*.rs)) \
-            $(wildcard $(S)src/test/*/*.rs   \
-                       $(S)src/test/*/*/*.rs) \
-            $(wildcard $(S)src/fuzzer/*.rs)
-
-PP_INPUTS_FILTERED = $(shell echo $(PP_INPUTS) | xargs grep -L no-reformat)
+  PP_INPUTS_FILTERED = $(shell echo $(PP_INPUTS) | xargs grep -L no-reformat)
+endif
 
 reformat: $(SREQ1)
 	@$(call E, reformat [stage1]: $@)