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Masahiro Yamada b1992c3772 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>

2024-05-10 04:34:52 +09:00

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SPDX-License-Identifier: GPL-2.0

ifdef building_out_of_srctree

symlinks := $(patsubst $(src)/%,%,$(wildcard $(src)/*.py))

quiet_cmd_symlink = SYMLINK $@ cmd_symlink = ln -fsn $(patsubst $(obj)/%,$(abspath $(srctree))/$(src)/%,$@) $@

always-y += $(symlinks) $(addprefix $(obj)/, $(symlinks)): FORCE $(call if_changed,symlink)

endif

quiet_cmd_gen_constants_py = GEN $@ cmd_gen_constants_py =
$(CPP) -E -x c -P $(c_flags) $< > $@ ;
sed -i '1,//d;' $@

always-y += constants.py $(obj)/constants.py: $(src)/constants.py.in FORCE $(call if_changed_dep,gen_constants_py)

clean-files := *.pyc *.pyo

645 B Raw Blame History

SPDX-License-Identifier: GPL-2.0

645 B

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