Date: Fri, 07 Nov 1997 12:49:16 -0800 From: Julian Elischer <julian@whistle.com> To: Kenneth Merry <ken@plutotech.com> Cc: hackers@FreeBSD.ORG Subject: Re: Newest Pentium bug (fatal) Message-ID: <34637ECC.59E2B600@whistle.com> 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
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