RFC: x86: Fall back to lazy binding for unrelocated IFUNC symbol [BZ #23240]

[Florian Weimer]

On 06/06/2018 04:50 PM, H.J. Lu wrote:
> On Wed, Jun 6, 2018 at 7:04 AM, Florian Weimer <fweimer@redhat.com> wrote:
>> On 06/05/2018 09:24 PM, Florian Weimer wrote:
>>>
>>> On 05/28/2018 09:51 PM, H.J. Lu wrote:
>>>>
>>>> Here is the updated patch.  It fails to back lazy binding only
>>>> if GOT is writable.
>>>
>>>
>>> I think this still sets a wrong incentive, as in “you need to have a
>>> writable GOT for full forwards compatibility with future library evolution”.
>>>
>>> I think if we detect an IFUNC-based relocation against a
>>> not-yet-fully-relocated object, we need to delay this relocation processing
>>> and perform a second pass of all delayed relocations.  I have a patch which
>>> needs a little bit of work, but looks quite promising (to me at least).
>>
>>
>> Here are my patches:
>>
>> https://sourceware.org/ml/libc-alpha/2018-06/msg00076.html
>> https://sourceware.org/ml/libc-alpha/2018-06/msg00077.html
>>
>> I hope they address your needs.
> 
> Do you have a git branch I can use?

I've pushed it to fw/bug21242.

Florian