[PATCH 20/28] aarch64: Add glibc-hwcaps support

[Adhemerval Zanella]

On 14/10/2020 11:08, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
>> On 01/10/2020 13:33, Florian Weimer via Libc-alpha wrote:
>>> At this point, only the "atomics" subdirectory is available,
>>> for libraries built using LSE atomics.
>>
>> LGTM, thanks.
>>
>> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
> 
> Thanks.  I didn't want to skip AArch64, but it's really more of a stub
> implementation:
> 
>>> +const char _dl_hwcaps_subdirs[] = "atomics";
> 
> Does this still make sense with GCC defaulting to -moutline-atomics for
> ARMv8a?  That's what I wonder.
> 
> Eventually, we need to define some levels for AArch64, and I'm not sure
> to what extent they would align with the official 8.X versions.  To me,
> they look more like a bouquet you can choose from.

I am not sure how ARM maintainers would like to handle it, either by
defining based on ARMv8.x revisions, a subsets of HWCAP capabilities,
or by not defining anything.

For now I think the atomic makes sense because of -moutline-atomics,
although it is essentially ARMv8.1.