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Subject: Re: FOR REVIEW: New x86-64 vsyscall vgetcpu()
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Steve Munroe <sjmunroe@us.ibm.com>
Cc: Andi Kleen <ak@suse.de>, discuss@x86-64.org, libc-alpha@sourceware.org,
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       vojtech@suse.cz
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Date: Fri, 16 Jun 2006 09:17:58 +1000
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> PowerPC has similar issues and could use VDSO/vsyscal to implement
> vgetcpu() as well. So we should get Ben Herrenschmidt involved to insure
> that we have a cross platform solution.

Except that I haven't yet found a way to pass the information to the
vdso... in the past, there used to be an SPRG that was readable by
userland that I could have used but I can't see that working on recent
CPUs. The PIR isn't quite portable (though the vDSO can have per-cpu
model) and we don't quite know for sure what's in there, especially on
shared processor machines.

Any idea ?

Ben.