On Tuesday, 2 April 2024 09:52:38 CEST Richard W.M. Jones wrote: > On Tue, Apr 02, 2024 at 07:40:33AM +0200, Andreas Schneider wrote: > > On Saturday, 30 March 2024 10:37:44 CEST Richard W.M. Jones wrote: > > > These are just my thoughts on a Saturday morning. Feedback welcome of > > > course. > > > > I find the use of the ifunc attribute is really uncommon at this place. I > > would expect it in ffmpeg or some media codecs. In xz it looks like it is > > only there to hook in the payload. The software I know normally uses > > target cloning. > > In hindsight it's suspicious, but it's not generally suspicious for a > project that needs to generate optimal code for different > sub-architectures (eg. something that does fast decompression) to use > the mechanism for that purpose, ifunc. > > That said, ifunc is a very complicated, fragile but powerful mechanism > and I'd like to know from the glibc developers what we should > look out for. For example: > > - Is it ever valid for ifunc to take control of functions in another > library? Can this be detected by ld.so? > > - Can some wrappers be developed to make it both easier and safer? Well, if it would do that. I took a quick look at xz and didn't see any specific code for an architecture flavor like x86_64-v3 or avx related. It lacks the implementation for that. All it did was adding the infrastructure without using it. I guess that the use of ifunc would is still be very rare. Target clones is what you normally see. -- _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
