Re: [PATCH 1/10] Cr4 is valid on some 486s

[Linus Torvalds]

On Sun, 13 Nov 2005, Alan Cox wrote:
>
> On Sul, 2005-11-13 at 20:00 +0100, Andi Kleen wrote:
> > It's a bad hack anyways. Better would be probably to use a uncached WC write.
> > I would rather use that.
> 
> I'm not clear that anything but lock operations have the required
> guarantee of atomicity relative to bus masters which are not processors.
> Especially so on intel.

The thing is, we wouldn't ever remove _all_ lock prefixes. Only the ones 
that already depend on SMP.

So the memory barriers etc that have lock prefixes even on UP would be 
totally untouched.

		Linus
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