Re: [PATCH] Athlon Prefetch workaround for 2.6.0test6

[Andi Kleen]

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
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