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Re: [RFC] [MIPS] Enable non-executable PT_GNU_STACK support v2
On Thu, 22 Dec 2016, Joseph Myers wrote:
> It's only if a version was released in glibc that you can't reassign it.
> I don't see why you can't change binutils to use version 4 for GNU_STACK
> (and then 5 for IFUNC), probably including on 2.27 branch - binaries built
> to use version 5 for GNU_STACK just won't work with glibc until it gets
> IFUNC support. The relevant rule is: glibc doesn't claim to support a
> version unless it supports all ABIs <= that version (that is, all ABIs
> used by binaries that give a version <= that version).
>
> It's OK for binaries to specify an ABI version higher than they require
> (which would, effectively, be the case for binaries built now that use
> version 5 for GNU_STACK - version 5 meaning, under the reassigned numbers,
> that you need a glibc supporting all of MIPS_PLT, UNIQUE, MIPS_O32_FP64,
> GNU_STACK and IFUNC - which is a stricter requirement than necessary, but
> it's OK for binaries to specify stricter requirements than necessary).
OK, this makes sense to me, thanks for the clarification.
Change reverted now then with commit 4d4f40e041ce ("MIPS/BFD: Remove
EI_ABIVERSION 5 allocation for PT_GNU_STACK support") and backported to
2.28 and 2.27 branches.
Happy festive season, everyone!
Maciej