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RE: Privileged Opcode
- To: "Federico Bianchi" <bianchi@pc-arte2.arte.unipi.it>
- Subject: RE: Privileged Opcode
- From: "Suhaib M. Siddiqi" <Ssiddiqi@InspirePharm.Com>
- Date: Thu, 29 Jul 1999 07:18:21 -0400
- Cc: "Cygwin-Xfree@Sourceware.Cygnus.Com" <cygwin-xfree@sourceware.cygnus.com>
Hi Federico,
> How strange....
>
> The PRIVILEGED_INSTRUCTION itself is a trap (I don't remember at hand
> its INT number, but it shouldn't matter) triggered whenever an user mode
> program runs ring 0 (kernel) or IOPL instructions, that is either opcodes
> directly involving the privilege mechanism (e.g. LGDT or LIDT, ARPL, LTR,
> etc.) or I/O related (IN*, OUT*, CLI/STI).
It is comming from ..Xserver/dix library code. On line 248 in main.c
the server is restarted if it was unable to obtain necessary parameters
from XF86Config file. On Cygwin the restart(1) code in main.c at line 248
is causing the SIGTRAP when the server starts. For now I have disabled this
feature
and will recompile the server to see what happen next ;-)
Thanks for looking at the code. You would be of great help if you could
hack that code for Windows.
Regards
Suhaib