svn commit: r249846 - in head/sys/boot: i386/btx/btx pc98/btx/btx
Dimitry Andric
dim at FreeBSD.org
Wed Apr 24 17:20:46 UTC 2013
Author: dim
Date: Wed Apr 24 17:20:45 2013
New Revision: 249846
URL: http://svnweb.freebsd.org/changeset/base/249846
Log:
When rebooting (exiting) from the BTX loader, make sure to restore the
GDT from the correct segment, otherwise a triple fault would be caused.
In some virtual environments (VMware, VirtualBox, etc) this could lead
to a unhandled error or hang in the guest emulation software.
Thanks to avg and jhb for a few hints in the right direction.
Noticed by: Jeremy Chadwick <jdc at koitsu.org> (and many others)
MFC after: 1 week
Modified:
head/sys/boot/i386/btx/btx/btx.S
head/sys/boot/pc98/btx/btx/btx.S
Modified: head/sys/boot/i386/btx/btx/btx.S
==============================================================================
--- head/sys/boot/i386/btx/btx/btx.S Wed Apr 24 16:52:03 2013 (r249845)
+++ head/sys/boot/i386/btx/btx/btx.S Wed Apr 24 17:20:45 2013 (r249846)
@@ -248,7 +248,7 @@ exit: cli # Disable interrupts
/*
* Restore the GDT in case we caught a kernel trap.
*/
- lgdt gdtdesc # Set GDT
+ lgdt %cs:gdtdesc # Set GDT
/*
* To 16 bits.
*/
Modified: head/sys/boot/pc98/btx/btx/btx.S
==============================================================================
--- head/sys/boot/pc98/btx/btx/btx.S Wed Apr 24 16:52:03 2013 (r249845)
+++ head/sys/boot/pc98/btx/btx/btx.S Wed Apr 24 17:20:45 2013 (r249846)
@@ -248,7 +248,7 @@ exit: cli # Disable interrupts
/*
* Restore the GDT in case we caught a kernel trap.
*/
- lgdt gdtdesc # Set GDT
+ lgdt %cs:gdtdesc # Set GDT
/*
* To 16 bits.
*/
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