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Date: Fri, 07 Nov 1997 12:49:16 -0800
From: Julian Elischer <julian@whistle.com>
Organization: Whistle Communications
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To: Kenneth Merry <ken@plutotech.com>
CC: hackers@FreeBSD.ORG
Subject: Re: Newest Pentium bug (fatal)
References: <199711072039.NAA09839@panzer.plutotech.com>
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Kenneth Merry wrote:
> 
> Julian Elischer wrote...
> > On a "genuine Intel" pentium (not pentium pro)
> > execution of the following sequence, 0xf0 0x0f 0xc7 0xc8
> >
> > will stop the processor. This is doable from user mode and in
> > 16bitmode, or in fact any mode.
> >
> > try the following c program.
> 
> > unsigned char x[] = { 0xfo, 0x0f, 0xc7, 0xc8 };
>                         ^^^^
> 
>         Shouldn't that be 0xf0?
> 
> > no idea about the pentium II or other pentium copies.
> > K6?
> >
> > other pentium variants?
> > versions?
> >
> > this one DEFINITLY dies:
> > CPU: Pentium (99.38-MHz 586-class CPU)
> >   Origin = "GenuineIntel"  Id = 0x525  Stepping=5
> >   Features=0x1bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>
> 
>         This one blows up:
> 
> CPU: Pentium (132.17-MHz 586-class CPU)
>   Origin = "GenuineIntel"  Id = 0x52b  Stepping=11
>   Features=0x1bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>
> 
>         I tried it on a 486 and a P6, both worked okay.
> 
>         This could definitely be a problem for people running shell
> servers, etc., on Pentium boxes.  Is there any way to work around it in
> software?

no..

> 
> Ken
> --
> Kenneth Merry
> ken@plutotech.com