kbuild: remove 'addtree' and 'flags' magic for header search paths

The 'addtree' and 'flags' in scripts/Kbuild.include are so compilecated
and ugly.

As I mentioned in [1], Kbuild should stop automatic prefixing of header
search path options.

I fixed up (almost) all Makefiles in the kernel. Now 'addtree' and
'flags' have been removed.

Kbuild still caters to add $(srctree)/$(src) and $(objtree)/$(obj)
to the header search path for O= building, but never touches extra
compiler options from ccflags-y etc.

[1]: https://patchwork.kernel.org/patch/9632347/

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 8 insertions, 18 deletions

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 41e98fa66b91..1b412d4394ae 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -137,36 +137,26 @@ _c_flags += $(if $(patsubst n%,, \
         $(CFLAGS_KCOV))
 endif
 
-__c_flags       = $(_c_flags)
-__a_flags       = $(_a_flags)
-__cpp_flags     = $(_cpp_flags)
-
-# If building the kernel in a separate objtree expand all occurrences
-# of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
+# $(srctree)/$(src) for including checkin headers from generated source files
+# $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
 ifneq ($(srctree),.)
-
-# -I$(obj) locates generated .h files
-# $(call addtree,-I$(obj)) locates .h files in srctree, from generated .c files
-#   and locates generated .h files
-# FIXME: Replace both with specific CFLAGS* statements in the makefiles
-__c_flags       = $(if $(obj),$(call addtree,-I$(src)) -I$(obj)) \
-                  $(call flags,_c_flags)
-__a_flags       = $(call flags,_a_flags)
-__cpp_flags     = $(call flags,_cpp_flags)
+_c_flags   += -I $(srctree)/$(src) -I $(objtree)/$(obj)
+_a_flags   += -I $(srctree)/$(src) -I $(objtree)/$(obj)
+_cpp_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj)
 endif
 endif
 
 c_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
                  -include $(srctree)/include/linux/compiler_types.h       \
-                 $(__c_flags) $(modkern_cflags)                           \
+                 $(_c_flags) $(modkern_cflags)                           \
                  $(basename_flags) $(modname_flags)
 
 a_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
-                 $(__a_flags) $(modkern_aflags)
+                 $(_a_flags) $(modkern_aflags)
 
 cpp_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
-                 $(__cpp_flags)
+                 $(_cpp_flags)
 
 ld_flags       = $(KBUILD_LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F))