Changes in Kbuild

b1992c37 - kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Sat, 27 Apr 2024 14:55:02 +0000

kbuild: use $(src) instead of $(srctree)/$(src) for source directoryKbuild conventionally uses $(obj)/ for generated files, and $(src)/ forchecked-in source files. It is merely a convention without any functionaldifference. In fact, $(obj) and $(src) are exactly the same, as definedin scripts/Makefile.build: src := $(obj)When the kernel is built in a separate output directory, $(src) doesnot accurately reflect the source directory location. While Kbuildresolves this discrepancy by specifying VPATH=$(srctree) to search forsource files, it does not cover all cases. For example, when adding aheader search path for local headers, -I$(srctree)/$(src) is typicallypassed to the compiler.This introduces inconsistency between upstream and downstream Makefilesbecause $(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 followingmeanings: $(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 treeConsequently, $(srctree)/$(src) in upstream Makefiles need to be replacedwith $(src).Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier List of files: /linux-6.15/arch/arm/Kbuild

8212f898 - kbuild: use more subdir- for visiting subdirectories while cleaning

Wed, 13 Oct 2021 06:36:22 +0000

kbuild: use more subdir- for visiting subdirectories while cleaningDocumentation/kbuild/makefiles.rst suggests to use "archclean" forcleaning arch/$(SRCARCH)/boot/, but it is not a hard requirement.Since commit d92cc4d51643 ("kbuild: require all architectures to havearch/$(SRCARCH)/Kbuild"), we can use the "subdir- += boot" trick forall architectures. This can take advantage of the parallel option (-j)for "make clean".I also cleaned up the comments in arch/$(SRCARCH)/Makefile. The "archdep"target no longer exists.Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Acked-by: Geert Uytterhoeven Acked-by: Michael Ellerman (powerpc) List of files: /linux-6.15/arch/arm/Kbuild

846484ea - ARM: 8981/1: add arch/arm/Kbuild

Tue, 26 May 2020 13:20:31 +0000

ARM: 8981/1: add arch/arm/KbuildUse the standard obj-y form to specify the sub-directories underarch/arm/. No functional change intended.Signed-off-by: Masahiro Yamada Signed-off-by: Russell King List of files: /linux-6.15/arch/arm/Kbuild