valgrind support for glibc master

[Szabolcs Nagy]

On 23/06/17 12:13, Florian Weimer wrote:
> On 06/23/2017 01:10 PM, Siddhesh Poyarekar wrote:
>> On Friday 23 June 2017 04:31 PM, Mark Wielaard wrote:
>>> For now the auxv HWCAP is masked off on arm64 in valgrind fedora.
>>> https://bugzilla.redhat.com/show_bug.cgi?id=1464211#c1
>>> So you can reenable the sanity check again on fedora rawhide.
>>>
>>> Upstream bug is https://bugs.kde.org/show_bug.cgi?id=381556
>>> arm64: Handle feature registers access on 4.11 Linux kernel or later
>>
>> A better workaround would be to mask out HWCAP_CPUID (0x800) from the HWCAP.
> 
> valgrind needs to mask out all unknown/unimplemented flags.  And I
> thought it was 1?  LD_HWCAP_MASK=1 acts as a workaround, after all.
> 

because LD_HWCAP_MASK is the 'important hwcap bits'
and now that is 0x800 by default on aarch64, if you
unset that flag then the cpuid check is disabled.