Commit b1992c37 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

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: default avatarMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: default avatarNicolas Schier <nicolas@fjasle.eu>
parent 9a0ebe50

Documentation/Makefile

+4 −4
Original line number Diff line number Diff line
@@ -76,22 +76,22 @@ loop_cmd = $(echo-cmd) $(cmd_$(1)) || exit; 
#    * dest folder relative to $(BUILDDIR) and

#    * cache folder relative to $(BUILDDIR)/.doctrees

# $4 dest subfolder e.g. "man" for man pages at userspace-api/media/man

# $5 reST source folder relative to $(srctree)/$(src),

# $5 reST source folder relative to $(src),

#    e.g. "userspace-api/media" for the linux-tv book-set at ./Documentation/userspace-api/media



quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)

      cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media $2 && \

	PYTHONDONTWRITEBYTECODE=1 \

	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \

	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(src)/$5/$(SPHINX_CONF)) \

	$(PYTHON3) $(srctree)/scripts/jobserver-exec \

	$(CONFIG_SHELL) $(srctree)/Documentation/sphinx/parallel-wrapper.sh \

	$(SPHINXBUILD) \

	-b $2 \

	-c $(abspath $(srctree)/$(src)) \

	-c $(abspath $(src)) \

	-d $(abspath $(BUILDDIR)/.doctrees/$3) \

	-D version=$(KERNELVERSION) -D release=$(KERNELRELEASE) \

	$(ALLSPHINXOPTS) \

	$(abspath $(srctree)/$(src)/$5) \

	$(abspath $(src)/$5) \

	$(abspath $(BUILDDIR)/$3/$4) && \

	if [ "x$(DOCS_CSS)" != "x" ]; then \

		cp $(if $(patsubst /%,,$(DOCS_CSS)),$(abspath $(srctree)/$(DOCS_CSS)),$(DOCS_CSS)) $(BUILDDIR)/$3/_static/; \

Documentation/devicetree/bindings/Makefile

+3 −3
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ quiet_cmd_extract_ex = DTEX $@ 
$(obj)/%.example.dts: $(src)/%.yaml check_dtschema_version FORCE

	$(call if_changed,extract_ex)



find_all_cmd = find $(srctree)/$(src) \( -name '*.yaml' ! \

find_all_cmd = find $(src) \( -name '*.yaml' ! \

		-name 'processed-schema*' \)



find_cmd = $(find_all_cmd) | \
@@ -37,12 +37,12 @@ CHK_DT_EXAMPLES := $(patsubst $(srctree)/%.yaml,%.example.dtb, $(shell $(find_cm 
quiet_cmd_yamllint = LINT    $(src)

      cmd_yamllint = ($(find_cmd) | \

                     xargs -n200 -P$$(nproc) \

		     $(DT_SCHEMA_LINT) -f parsable -c $(srctree)/$(src)/.yamllint >&2) \

		     $(DT_SCHEMA_LINT) -f parsable -c $(src)/.yamllint >&2) \

		     && touch $@ || true



quiet_cmd_chk_bindings = CHKDT   $(src)

      cmd_chk_bindings = ($(find_cmd) | \

			  xargs -n200 -P$$(nproc) $(DT_DOC_CHECKER) -u $(srctree)/$(src)) \

			  xargs -n200 -P$$(nproc) $(DT_DOC_CHECKER) -u $(src)) \

			  && touch $@ || true



quiet_cmd_mk_schema = SCHEMA  $@

Documentation/kbuild/makefiles.rst

+6 −6
Original line number Diff line number Diff line
@@ -346,7 +346,7 @@ ccflags-y, asflags-y and ldflags-y 
  Example::



    #arch/cris/boot/compressed/Makefile

    ldflags-y += -T $(srctree)/$(src)/decompress_$(arch-y).lds

    ldflags-y += -T $(src)/decompress_$(arch-y).lds



subdir-ccflags-y, subdir-asflags-y

  The two flags listed above are similar to ccflags-y and asflags-y.
@@ -426,14 +426,14 @@ path to prerequisite files and target files. 
Two variables are used when defining custom rules:



$(src)

  $(src) is a relative path which points to the directory

  where the Makefile is located. Always use $(src) when

  $(src) is the directory where the Makefile is located. Always use $(src) when

  referring to files located in the src tree.



$(obj)

  $(obj) is a relative path which points to the directory

  where the target is saved. Always use $(obj) when

  referring to generated files.

  $(obj) is the directory where the target is saved. Always use $(obj) when

  referring to generated files. Use $(obj) for pattern rules that need to work

  for both generated files and real sources (VPATH will help to find the

  prerequisites not only in the object tree but also in the source tree).



  Example::

Makefile

+7 −0
Original line number Diff line number Diff line
@@ -263,7 +263,14 @@ srctree := $(abs_srctree) 
endif



objtree		:= .



VPATH		:=



ifeq ($(KBUILD_EXTMOD),)

ifdef building_out_of_srctree

VPATH		:= $(srctree)

endif

endif



export building_out_of_srctree srctree objtree VPATH

arch/arc/boot/dts/Makefile

+1 −2
Original line number Diff line number Diff line
@@ -10,8 +10,7 @@ obj-y += $(builtindtb-y).dtb.o 
dtb-y := $(builtindtb-y).dtb



# for CONFIG_OF_ALL_DTBS test

dtstree	:= $(srctree)/$(src)

dtb-	:= $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts))

dtb-	:= $(patsubst $(src)/%.dts,%.dtb, $(wildcard $(src)/*.dts))



# board-specific dtc flags

DTC_FLAGS_hsdk += --pad 20