linux-kernel - [PATCH 0/3] [GIT PULL][3.6] x86: cr2 and cmpxchg issues of NMI

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Date:	Fri, 08 Jun 2012 09:52:00 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	linux-kernel@...r.kernel.org
Cc:	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 0/3] [GIT PULL][3.6] x86: cr2 and cmpxchg issues of NMI

Ingo,

As Avi brought to attention, there may be issues with NMIs and page faults
as if a NMI takes a page fault it can corrupt the cr2 for a page fault
handler that it preempted. The first and third patch fixes this for x86_64
and i386 respectively.

The second patch is to fix the cmpxchg issue brought up by someone on LWN.
The NMI handler for i386 uses cmpxchg to handle nested NMIs. But some
older i386 boxes do not have a true cmpxchg and this will fail for them.
Luckily, there is a simple fix that also makes the code cleaner.

Please pull the latest tip/x86/core tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/x86/core

Head SHA1: 7fefda3109021f98926d76a13f90d0b116ce3db5

Steven Rostedt (3):
      x86: Save cr2 in NMI in case NMIs take a page fault
      x86: Remove cmpxchg from i386 NMI nesting code
      x86: Save cr2 in NMI in case NMIs take a page fault (for i386)

----
 arch/x86/kernel/entry_64.S |   20 +++++++++++++++++
 arch/x86/kernel/nmi.c      |   51 +++++++++++++++++++++++++++++++-------------
 2 files changed, 56 insertions(+), 15 deletions(-)

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