kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

    src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

  $(obj)     - directory in the object tree
  $(src)     - directory in the source tree  (changed by this commit)
  $(objtree) - the top of the kernel object tree
  $(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

1 files changed, 4 insertions, 4 deletions

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index ea1bf3b3dbde..a0a0be38cbdc 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -57,7 +57,7 @@ $(foreach c, config menuconfig nconfig gconfig xconfig, $(eval $(call config_rul
 
 PHONY += localmodconfig localyesconfig
 localyesconfig localmodconfig: $(obj)/conf
-	$(Q)$(PERL) $(srctree)/$(src)/streamline_config.pl --$@ $(srctree) $(Kconfig) > .tmp.config
+	$(Q)$(PERL) $(src)/streamline_config.pl --$@ $(srctree) $(Kconfig) > .tmp.config
 	$(Q)if [ -f .config ]; then 				\
 		cmp -s .tmp.config .config ||			\
 		(mv -f .config .config.old.1;			\
@@ -118,7 +118,7 @@ tinyconfig:
 # CHECK: -o cache_dir=<path> working?
 PHONY += testconfig
 testconfig: $(obj)/conf
-	$(Q)$(PYTHON3) -B -m pytest $(srctree)/$(src)/tests \
+	$(Q)$(PYTHON3) -B -m pytest $(src)/tests \
 	-o cache_dir=$(abspath $(obj)/tests/.cache) \
 	$(if $(findstring 1,$(KBUILD_VERBOSE)),--capture=no)
 clean-files += tests/.cache
@@ -165,8 +165,8 @@ common-objs	:= confdata.o expr.o lexer.lex.o menu.o parser.tab.o \
 		   preprocess.o symbol.o util.o
 
 $(obj)/lexer.lex.o: $(obj)/parser.tab.h
-HOSTCFLAGS_lexer.lex.o	:= -I $(srctree)/$(src)
-HOSTCFLAGS_parser.tab.o	:= -I $(srctree)/$(src)
+HOSTCFLAGS_lexer.lex.o	:= -I $(src)
+HOSTCFLAGS_parser.tab.o	:= -I $(src)
 
 # conf: Used for defconfig, oldconfig and related targets
 hostprogs	+= conf