linux/usr
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
..
dummy-include kbuild: prevent exported headers from including <stdlib.h>, <stdbool.h> 2022-05-13 10:56:10 +02:00
include kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
.gitignore .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
default_cpio_list initramfs: add default_cpio_list, and delete -d option support 2020-01-16 00:25:22 +09:00
gen_init_cpio.c gen_init_cpio: Apply mtime supplied by user to all file types 2023-12-29 22:25:21 +09:00
gen_initramfs.sh initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
initramfs_data.S initramfs: refactor the initramfs build rules 2020-01-16 00:26:21 +09:00
Kconfig usr/Kconfig: fix typos of "its" 2023-12-20 15:02:58 -08:00
Makefile kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00