Re: [patch] SMP alternatives

From: Alan Cox
Date: Wed Nov 23 2005 - 11:10:03 EST

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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