Re: [PATCH 3/4] build: also check for empty .bss.* in .o -> .init.o conversion

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 06/08/2020 10:05, Jan Beulich wrote:
> We're gaining such sections, and like .text.* and .data.* they shouldn't
> be present in objects subject to automatic to-init conversion. Oddly
> enough for quite some time we did have an instance breaking this rule,
> which gets fixed at this occasion, by breaking out the EFI boot
> allocator functions into its own translation unit.
>
> Fixes: c5b9805bc1f7 ("efi: create new early memory allocator")
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

> ---
> This likely has a (weak) dependency on "x86/EFI: sanitize build logic"
> sent several weeks ago, due to the new source file added, as explicit
> dependencies upon the individual objects in x86/Makefile go away there.
>
> --- a/xen/Makefile
> +++ b/xen/Makefile
> @@ -355,7 +355,7 @@ $(TARGET): delete-unfresh-files
>       $(MAKE) -C tools
>       $(MAKE) -f $(BASEDIR)/Rules.mk include/xen/compile.h
>       [ -e include/asm ] || ln -sf asm-$(TARGET_ARCH) include/asm
> -     [ -e arch/$(TARGET_ARCH)/efi ] && for f in boot.c runtime.c compat.c 
> efi.h;\
> +     [ -e arch/$(TARGET_ARCH)/efi ] && for f in $$(cd common/efi; echo 
> *.[ch]); \
>               do test -r arch/$(TARGET_ARCH)/efi/$$f || \
>                  ln -nsf ../../../common/efi/$$f arch/$(TARGET_ARCH)/efi/; \
>               done; \

Maybe not for this patch, but we need to start removing this (and other)
symlinking in the tree for proper out-of-tree builds to work.

AFAICT, this logic predates both Kconfig and x86's blur into having EFI
support in xen.gz.

Can't we remove all of this by having CONFIG_XEN_PE expressed/selectable
properly in Kconfig, and gathering all the objects normally, rather than
bodging all of common/efi/ through arch/efi/ ?

~Andrew