On 9.8.2013 13:07, Mark Brown wrote: > From: John Rigby <john.rigby@xxxxxxxxxx> > > Cross compiling the binaries in scripts/* is not possible > because various makefiles assume that $(obj)/whatever is > executable on the build host. What is the use case for cross-compiling them? If you have a powerful enough target machine to build the kernel on it, you can as well compile the host scripts natively, can't you? But maybe I'm missing something, I do not cross-compile the kernel on a daily basis. Are there other projects that have such feature in their build system? > This patch introduces a new variable called KBUILD_SCRIPTROOT > that points to script/binaries to use while cross compiling. > > Usage: > > Build scripts for the build host: > make O=path/to/buildhost/buildscripts \ > silentoldconfig prepare scripts > Then cross build script for target: > make O=path/to/target/buildscripts \ > HOSTCC=$CROSS_COMPILE \ > KBUILD_SCRIPTROOT=path/to/buildhost/buildscripts > silentoldconfig prepare scripts Note that a build that uses KBUILD_SCRIPTROOT cannot detect if the scripts are up to date and cannot rebuild them. This must be documented. > This patch does not use KBUILD_SCRIPTROOT for all script invocations > it only redefines the following if KBUILD_SCRIPTROOT is defined. > > scripts/Makefile.build > scripts/basic/fixdep --> $(KBUILD_SCRIPTROOT)/scripts/basic/fixdep > > scripts/kconfig/Makefile > $(obj)/conf --> $(KBUILD_SCRIPTROOT)/scripts/kconfig/conf > > scripts/mod/Makefile > $(obj)mk_elfconfig --> $(KBUILD_SCRIPTROOT)/scripts/mod/mk_elfconfig OK, but you might need to add a couple of more of them, like lib/gen_crc32table. > diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include > index 547e15d..09aa90c 100644 > --- a/scripts/Kbuild.include > +++ b/scripts/Kbuild.include > @@ -222,11 +222,15 @@ if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ > $(echo-cmd) $(cmd_$(1)); \ > echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) > > +ifeq ($(KBUILD_SCRIPTROOT),) > +KBUILD_SCRIPTROOT=. > +endif > + This should be set in the top level Makefile once. Thanks, Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
