Date: Fri, 7 Nov 1997 13:39:45 -0700 (MST) From: Kenneth Merry <ken@plutotech.com> To: julian@whistle.com (Julian Elischer) Cc: hackers@FreeBSD.ORG Subject: Re: Newest Pentium bug (fatal) Message-ID: <199711072039.NAA09839@panzer.plutotech.com> In-Reply-To: <3463605C.41C67EA6@whistle.com> from Julian Elischer at "Nov 7, 97 10:39:24 am"
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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?
Ken
--
Kenneth Merry
ken@plutotech.com
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