Date: Thu, 13 Nov 1997 14:25:18 -0500 From: Christopher Masto <chris@netmonger.net> To: Terry Lambert <tlambert@primenet.com> Cc: freebsd-current@FreeBSD.ORG Subject: Re: Intel Pentium Bug: BSDI Releases a patch (fwd) Message-ID: <19971113142518.53705@netmonger.net> In-Reply-To: <199711131918.MAA29928@usr08.primenet.com>; from Terry Lambert on Thu, Nov 13, 1997 at 07:18:38PM %2B0000 References: <64fa86$bbu$1@schenectady.netmonger.net> <199711131918.MAA29928@usr08.primenet.com>
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On Thu, Nov 13, 1997 at 07:18:38PM +0000, Terry Lambert wrote: > > 'LOW PAGE' is unmapped, 'HIGH PAGE' is mapped. So Linux will see > > a 'bounced exception' in the page fault handler only if exceptions 0-6 > > happen ... they are very rare. The BSDI fix seems to cut at exception > > 13, which thus includes important exceptions like the lazy-FPU exception. > > Linux does not have this overhead. > > Why do they do it at 13 if they don't have to? > > What did Intel tell them that they didn't tell us that makes them > willing to take the additional 7 IDT entry hit? I wish I knew (not that I have much Intel knowledge beyond 8086). I do know that I'm glad we didn't cancel our K6 order upon seeing that there appears to be an emerging software workaround. Two things still make me nervous (both "seen on the net" but unconfirmed): someone said that BSDI's patch is now listed as "unavailable", and someone else said that their Linux system still locked up after applying the patch. Maybe it doesn't work in all cases. :-/ -- = Christopher Masto = chris@netmonger.net = http://www.netmonger.net/ = = NetMonger Communications = finger for PGP key = $19.95/mo unlimited access = = Director of Operations = (516) 221-6664 = mailto:info@netmonger.net = "... who'd want a lossy TIFF?" -- Kibo
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