From 9e4140329ee9a787d0f96ac2829d618d47f7973f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 4 Feb 2014 17:24:24 +0900 Subject: kbuild: change out-of-tree build This commit changes the working directory where the build process occurs. Before this commit, build process occurred under the source tree for both in-tree and out-of-tree build. That's why we needed to add $(obj) prefix to all generated files in makefiles like follows: $(obj)u-boot.bin: $(obj)u-boot Here, $(obj) is empty for in-tree build, whereas it points to the output directory for out-of-tree build. And our old build system changes the current working directory with "make -C " syntax when descending into the sub-directories. On the other hand, Kbuild uses a different idea to handle out-of-tree build and directory descending. The build process of Kbuild always occurs under the output tree. When "O=dir/to/store/output/files" is given, the build system changes the current working directory to that directory and restarts the make. Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=" syntax for descending into sub-directories. (We can write it like "make $(obj)=" with a shorthand.) This means the current working directory is always the top of the output directory. Signed-off-by: Masahiro Yamada Tested-by: Gerhard Sittig --- scripts/Kbuild.include | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index ca5fd56ca25..6113c13d161 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -165,9 +165,7 @@ ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2)) # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= # Usage: # $(Q)$(MAKE) $(build)=dir -#build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj -# temporary -build := -f $(srctree)/scripts/Makefile.build -C +build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj ### # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj= -- cgit v1.2.3