Date: Mon, 18 Aug 2008 08:47:27 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/amd64/amd64 exception.S Message-ID: <200808180847.m7I8lipW096866@repoman.freebsd.org>
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kib 2008-08-18 08:47:27 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 exception.S
Log:
SVN rev 181823 on 2008-08-18 08:47:27Z by kib
The doreti_iret_fault code is always called with gs base MSR containing
kernel gs base, because %rip is adjusted only on kernel-mode trap caused
by iretq execution. On the other hand, the stack contains (hardware
part of) trap frame from the usermode. As a consequence, checking for
frame mode and doing swapgs causes the kernel to enter trap() with
usermode gs base.
Remove the check for mode and conditional swapgs, we already have right
gs base in the MSR.
Submitted by: Nate Eldredge <neldredge math ucsd edu>
MFC after: 3 days
Revision Changes Path
1.133 +3 -6 src/sys/amd64/amd64/exception.S
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