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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