Re: [XEN PATCH 07/15] build: move XEN_HAS_BUILD_ID out of Config.mk

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.05.2023 18:38, Anthony PERARD wrote:
> Whether or not the linker can do build id is only used by the
> hypervisor build, so move that there.
> 
> Rename $(build_id_linker) to $(XEN_LDFLAGS_BUILD_ID) as this is a
> better name to be exported as to use the "XEN_*" namespace.
> 
> Also update XEN_TREEWIDE_CFLAGS so flags can be used for
> arch/x86/boot/ CFLAGS_x86_32
> 
> Beside a reordering of the command line where CFLAGS is used, there
> shouldn't be any other changes.
> 
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
with one nit:

> --- a/xen/scripts/Kbuild.include
> +++ b/xen/scripts/Kbuild.include
> @@ -91,6 +91,9 @@ cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) 
> $(2)000 ] && echo $(3) || e
>  
>  clang-ifversion = $(shell [ $(CONFIG_CLANG_VERSION)0 $(1) $(2)000 ] && echo 
> $(3) || echo $(4))
>  
> +ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
> +                                     grep -q build-id && echo n || echo y)

I realize you only move this line, but I think we want indentation here
to improve at this occasion:

ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
                          grep -q build-id && echo n || echo y)

I'll be happy to adjust while committing. Which raises the question: Is
there any dependency here on earlier patches in the series? It doesn't
look so to me, but I may easily be overlooking something. (Of course
first further arch maintainer acks would be needed.)

> --- a/xen/test/livepatch/Makefile
> +++ b/xen/test/livepatch/Makefile
> @@ -37,7 +37,7 @@ $(obj)/modinfo.o:
>  
>  #
>  # This target is only accessible if CONFIG_LIVEPATCH is defined, which
> -# depends on $(build_id_linker) being available. Hence we do not
> +# depends on $(XEN_LDFLAGS_BUILD_ID) being available. Hence we do not
>  # need any checks.

As an aside, I'm a little confused by "is only accessible" here. I don't
see how CONFIG_LIVEPATCH controls reachability. At the very least the
parent dir's Makefile doesn't use CONFIG_LIVEPATCH at all.

Jan