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Re: [PATCH, GOLD, AArch64] default stack not executable


On Thu, Sep 21, 2017 at 5:26 PM, Cary Coutant <ccoutant@gmail.com> wrote:
> I don't see why aarch64 should be treated differently from other
> targets here, unless you can claim that there is no such thing as an
> old object that requires an executable stack but does not contain a
> stack note to that effect. If that's the case for aarch64 (and Han
> agrees), I'll support this patch.

GNU-stack notes were added in 2004.  The aarch64 port was added in
2012.  So yes, there are no old object files that predate the
GNU-stack notes, which is why aarch64 ld.bfd ignores a missing
GNU-stack note.

> Since you raise the possibility that ppc should also default to false,
> I'll ask Alan the same question: are there old objects that must be
> assumed to require an executable stack?

That should be 64-bit ppc only.  32-bit ppc has old object files that
we need to be compatible with.  Though I'm not sure what the
justification is for 64-bit ppc, since it did exist before GNU-stack
notes.  Maybe this is because of the new ABI that rolled out a few of
years ago?   Checking ChangeLogs, I see that execstack was turned off
for 64-bit ppc in 2007.

Jim


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