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Subject: Re: [patch] SMP alternatives
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Andi Kleen <ak@suse.de>
Cc: Gerd Knorr <kraxel@suse.de>, Linus Torvalds <torvalds@osdl.org>,
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References: <200511100032.jAA0WgUq027712@zach-dev.vmware.com>
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	 <Pine.LNX.4.64.0511131210570.3263@g5.osdl.org> <4378A7F3.9070704@suse.de>
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Date: Wed, 23 Nov 2005 16:42:13 +0000
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On Mer, 2005-11-23 at 12:17 -0700, Andi Kleen wrote:
> > +	/* Paranoia */
> > +	asm volatile ("jmp 1f\n1:");
> > +	mb();
> 
> That would be totally obsolete 386 era paranoia. If anything then use 
> a CLFLUSH (but not available on all x86s) 

If you are patching code another x86 CPU is running you must halt the
other processors and ensure it executes a serialzing instruction before
it enters any patched code. 

How many kilobytes of tables do you add to the kernel to do this
pointless stunt btw ?

Alan "CPU errata are fun" Cox

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