Date: Thu, 29 Jun 2000 02:51:54 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/boot/i386/btx/btx btx.s Message-ID: <200006290951.CAA16896@freefall.freebsd.org>
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jhb 2000/06/29 02:51:54 PDT
Modified files:
sys/boot/i386/btx/btx btx.s
Log:
Note that the cleaning up and reordering in revision 1.19 actually fixed a
nasty bug. The comparison to tset for an instruciton with the $0xf prefix
should have jumped down to the next non-prefix instruction test. Instead,
it jumped down to the next instruction test, which happened to be prefixed
instruction test. This test assumed that the earlier test had succeeded,
thus in some rare cases, this test would actually succeed, and we would
actually attempt to emulate a RDMSR instruction instead of the instruction
we were supposed to be emulating. Since %ecx usually did not contain a
valid MSR index at the time of the trap, this usually resulted in a #GP
due to an invalid MSR address and a lovely BTX fault when one tried to boot
the machine.
Noticed by: unfurl and others
Revision Changes Path
1.21 +1 -1 src/sys/boot/i386/btx/btx/btx.s
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