Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [RFC PATCH] UAPI: Document auxvec AT_* namespace policy and note reservations | Date | Thu, 17 May 2018 16:40:19 +1000 |
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Dave Martin <Dave.Martin@arm.com> writes:
> There are constraints on defining AT_* auxvec tags that are not > obvious to the casual maintainer of either the global > <uapi/linux/auxvec.h> or the arch-specific headers. This is likely > to lead to mistakes. (I certainly fell foul of it...)
Thanks for cleaning this up.
It looks like us (powerpc) / me is the main offender here.
My excuse is it was glibc folk who asked us to add all those new AT_ entries in the first place. </buckpassing>
> For the benefit of future maintainers, this patch collects the > relevant information in one place, documenting how the namespace > needs to be managed, and noting all the values currently in use. > > Maintaining a global list may result in some merge conflicts, but > AT_* values are not added frequently. I'm open to suggestions on > the best approach.
Yeah I agree with Rich that having a global list would be best. That is the most reliable to make people think twice about adding new entries.
> I also assume that values 38 and 39 may have been used for > historical purposes, such as an architecture that is no longer > supported. If they have definitely never been used for anything, > they could be removed from the "reserved" list.
I don't know why we added the new entries starting at 40, maybe Ben remembers. Quite likely it was just an accident.
I don't see any sign of 38 or 39 in glibc history.
cheers
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