[x86-64 psABI] x86-64 micro-architecture levels

[H.J. Lu]

x86-64 psABI has been updated with 4 micro-architecture levels. The
current x86-64 psABI PDF file can be downloaded from

https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/x86-64-psABI

--
H.J.

[H.J. Lu]

Since tools with 4 ISA level support can generate libfoo.so with different
ISA level requirements, we need a way to what the ISA level is required
for libfoo.so. I propose to add GNU_PROPERTY_X86_ISA_1_USED
and GNU_PROPERTY_X86_ISA_1_NEEDED to mark an object with
ISA level used and needed.

--
H.J.

[Florian Weimer]

* H. J. Lu:

Shouldn't this be evident from the feature flags encoded in the
properties?

A hypothetical future dynamic loader could look at the individual bits
and not load objects that require more than the current system can
support.

Thanks,
Florian

[H.J. Lu]

On Fri, Aug 7, 2020 at 9:28 AM Florian Weimer <fwe...@redhat.com> wrote:
>
> * H. J. Lu:
>
> > On Fri, Aug 7, 2020 at 7:38 AM H.J. Lu <hjl....@gmail.com> wrote:
> >>
> >> x86-64 psABI has been updated with 4 micro-architecture levels. The
> >> current x86-64 psABI PDF file can be downloaded from
> >>
> >> https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/x86-64-psABI
> >>
> >
> > Since tools with 4 ISA level support can generate libfoo.so with different
> > ISA level requirements, we need a way to what the ISA level is required
> > for libfoo.so. I propose to add GNU_PROPERTY_X86_ISA_1_USED
> > and GNU_PROPERTY_X86_ISA_1_NEEDED to mark an object with
> > ISA level used and needed.
>
> Shouldn't this be evident from the feature flags encoded in the
> properties?

I created a merge request:

https://gitlab.com/x86-psABIs/x86-64-ABI/-/merge_requests/13

> A hypothetical future dynamic loader could look at the individual bits
> and not load objects that require more than the current system can
> support.
>

Yes, it is the intention.

--
H.J.