Date: Wed, 9 Jul 2008 13:39:58 -0700
From: Arjan van de Ven <arjan@infradead.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>, "Eric W. Biederman" <ebiederm@xmission.com>,
       Mike Travis <travis@sgi.com>, Andrew Morton <akpm@linux-foundation.org>,
       "H. Peter Anvin" <hpa@zytor.com>,
       Christoph Lameter <cl@linux-foundation.org>,
       Jack Steiner <steiner@sgi.com>, linux-kernel@vger.kernel.org
Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses
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On Wed, 09 Jul 2008 13:11:03 -0700
Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> Ingo Molnar wrote:
> > Note that the zero-based percpu problems are completely unrelated
> > to stackprotector. I was able to hit them with a
> > stackprotector-disabled gcc-4.2.3 environment.
> 
> The only reason we need to keep a zero-based pda is to support 
> stack-protector.  If we drop drop it, we can drop the pda - and its 
> special zero-based properties - entirely.

what's wrong with zero based btw?

do they stop us from using gcc's __thread keyword for per cpu variables
or something? (*that* would be a nice feature)

or does it stop us from putting the per cpu variables starting from
offset 4096 onwards?

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