diff --git a/Makefile b/Makefile
index ad0add0..ed65de7 100644
--- a/Makefile
+++ b/Makefile
@@ -318,7 +318,7 @@
                    $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) \
 		   -include include/linux/autoconf.h
 
-CPPFLAGS        := -D__KERNEL__ $(LINUXINCLUDE)
+KBUILD_CPPFLAGS := -D__KERNEL__ $(LINUXINCLUDE)
 
 KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 		   -fno-strict-aliasing -fno-common \
@@ -334,7 +334,7 @@
 export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE
 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 
-export CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
+export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 
@@ -523,9 +523,10 @@
 # disable pointer signed / unsigned warnings in gcc 4.0
 KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,)
 
-# Add user supplied AFLAGS and CFLAGS as the last assignments
-KBUILD_AFLAGS += $(AFLAGS)
-KBUILD_CFLAGS += $(CFLAGS)
+# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
+KBUILD_CPPFLAGS += $(CPPFLAGS)
+KBUILD_AFLAGS   += $(AFLAGS)
+KBUILD_CFLAGS   += $(CFLAGS)
 
 # Use --build-id when available.
 LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
@@ -1507,7 +1508,7 @@
 
 
 a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
-	  $(NOSTDINC_FLAGS) $(CPPFLAGS) \
+	  $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
 	  $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
 
 quiet_cmd_as_o_S = AS      $@