Date: 30 Sep 2003 07:38:03 +0200
Date: Tue, 30 Sep 2003 07:38:03 +0200
From: Andi Kleen <ak@colin2.muc.de>
To: Jamie Lokier <jamie@shareable.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Athlon Prefetch workaround for 2.6.0test6
Message-ID: <20030930053803.GA75928@colin2.muc.de>
References: <20030929125629.GA1746@averell> <20030929170323.GC21798@mail.jlokier.co.uk> <20030929174910.GA90905@colin2.muc.de> <20030929221346.GA25171@mail.jlokier.co.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20030929221346.GA25171@mail.jlokier.co.uk>
User-Agent: Mutt/1.4.1i
Sender: linux-kernel-owner@vger.kernel.org

On Mon, Sep 29, 2003 at 11:13:46PM +0100, Jamie Lokier wrote:
> Andi Kleen wrote:
> > I guess they should be added to the AMD64 version too. It ignores
> > all bases, but I'm not sure if the CPU catches the case where the linear
> > address computation wraps.
> 
> The linear address is _allowed_ to wrap on x86, and there are real
> DOS-era programs which take advantage of this.  It is used to create
> the illusion of access to high addresses, by making them wrap to low
> ones which can be mapped.

Only when the A20 gate is set (?), which it never is in Linux.

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/