On Thu, Jul 07, 2016 at 11:26:01AM +0100, Catalin Marinas wrote: > On Wed, Jul 06, 2016 at 06:57:39PM +0100, Catalin Marinas wrote: > > On Thu, May 12, 2016 at 05:39:15PM +0100, Kevin Brodsky wrote: > > > +# We need to generate vdso-offsets.h before compiling certain files in kernel/. > > > +# In order to do that, we should use the archprepare target, but we can't since > > > +# asm-offsets.h is included in some files used to generate vdso-offsets.h, and > > > +# asm-offsets.h is built in prepare0, for which archprepare is a dependency. > > > +# Therefore we need to generate the header after prepare0 has been made, hence > > > +# this hack. > > > +prepare: vdso_prepare > > > +vdso_prepare: prepare0 > > > + $(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h > > > > This indeed looks dodgy. I'm not sure about the makefile rules but would > > the above override the "prepare" target in the top Makefile? > > > > I think a dependency problem we have is that arch/arm64/kernel/signal.o > > depends on include/generated/vdso-offsets.h. However, we don't have any > > target for the latter, only for > > $(objtree)arch/arm64/kernel/vdso/vdso-offsets.h which no-one is > > including. Because of this, we have a fake dependency in > > arch/arm64/kernel/Makefile. > > > > -----------8<------------------------- > > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile > > index 7700c0c23962..9bdacbf59091 100644 > > --- a/arch/arm64/kernel/Makefile > > +++ b/arch/arm64/kernel/Makefile > > @@ -55,5 +55,4 @@ head-y := head.o > > extra-y += $(head-y) vmlinux.lds > > > > # vDSO - this must be built first to generate the symbol offsets > > -$(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h > > -$(obj)/vdso/vdso-offsets.h: $(obj)/vdso > > +$(objtree)/include/generated/vdso-offsets.h: $(obj)/vdso > > This didn't work either. Basically, when building > arch/arm64/kernel/signal.o for example, it doesn't figure out that > vdso-offsets.h has additional dependencies like the vdso.so.dbg so that > it builds the vdso object first. I'll look for a little longer, maybe I > find a better workaround. If I also add the patch below, it works fine but I'm not sure we can guarantee that kbuild first dives into subdirectories with a parallel build: --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -49,11 +49,7 @@ arm64-obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o arm64-obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o \ cpu-reset.o -obj-y += $(arm64-obj-y) vdso/ +obj-y += vdso/ $(arm64-obj-y) obj-m += $(arm64-obj-m) head-y := head.o extra-y += $(head-y) vmlinux.lds -- Catalin -- 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
