Re: [XEN PATCH v7 42/51] build: grab common EFI source files in arch specific dir

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Thu, Oct 14, 2021 at 10:51:44AM +0200, Jan Beulich wrote:
> On 24.08.2021 12:50, Anthony PERARD wrote:
> > --- a/xen/arch/arm/efi/Makefile
> > +++ b/xen/arch/arm/efi/Makefile
> > @@ -1,4 +1,10 @@
> >  CFLAGS-y += -fshort-wchar
> > +CFLAGS-y += -I$(srctree)/common/efi
> 
> Perhaps another opportunity for -iquote?

Yes.

> >  obj-y += boot.init.o pe.init.o ebmalloc.o runtime.o
> >  obj-$(CONFIG_ACPI) +=  efi-dom0.init.o
> > +
> > +$(obj)/%.c: common/efi/%.c
> > +   $(Q)cp -f $< $@
> 
> In case both trees are on the same file system, trying to hardlink first
> would seem desirable. When copying, I think you should also pass -p.

I don't know if doing an hardlink is a good thing to do, I'm not sure of
the kind of issue this could bring. As for -p, I don't think it's a good
idea to copy the mode, ownership, and timestamps of the source file, I'd
rather have the timestamps that Make expect, e.i. "now".

> > --- a/xen/arch/x86/efi/Makefile
> > +++ b/xen/arch/x86/efi/Makefile
> > @@ -1,4 +1,5 @@
> >  CFLAGS-y += -fshort-wchar
> > +CFLAGS-y += -I$(srctree)/common/efi
> >  
> >  quiet_cmd_objcopy_o_ihex = OBJCOPY $@
> >  cmd_objcopy_o_ihex = $(OBJCOPY) -I ihex -O binary $< $@
> > @@ -19,3 +20,8 @@ obj-$(XEN_BUILD_EFI) := $(filter-out %.init.o,$(EFIOBJ-y))
> >  obj-bin-$(XEN_BUILD_EFI) := $(filter %.init.o,$(EFIOBJ-y))
> >  extra-$(XEN_BUILD_EFI) += buildid.o relocs-dummy.o
> >  nocov-$(XEN_BUILD_EFI) += stub.o
> > +
> > +$(obj)/%.c: common/efi/%.c
> > +   $(Q)cp -f $< $@
> > +
> > +.PRECIOUS: $(obj)/%.c
> 
> Seeing you repeat everything here, despite it not being all this much I
> wonder if there wouldn't better be a makefile fragment in common/efi/
> which all interested architectures' arch/<arch>/efi/Makefile would then
> include. This could then also subsume -fshort-wchar.

That sounds good, I'll look into that.

Thanks,

-- 
Anthony PERARD