From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Steven Rostedt <rostedt@rostedt.homelinux.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>, Li Zefan <lizf@cn.fujitsu.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Johannes Berg <johannes.berg@intel.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Tom Zanussi <tzanussi@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Andi Kleen <andi@firstfloor.org>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
akpm@osdl.org, "H. Peter Anvin" <hpa@zytor.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
"Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: [patch 2/2] x86 NMI-safe INT3 and Page Fault
Date: Wed, 14 Jul 2010 17:42:21 +0100 (BST) [thread overview]
Message-ID: <alpine.LFD.2.00.1007141732200.11778@eddie.linux-mips.org> (raw)
In-Reply-To: <20100714155804.252253097@efficios.com>
On Wed, 14 Jul 2010, Mathieu Desnoyers wrote:
> This patch makes all faults, traps and exception safe to be called from NMI
> context *except* single-stepping, which requires iret to restore the TF (trap
> flag) and jump to the return address in a single instruction. Sorry, no kprobes
Watch out for the RF flag too, that is not set correctly by POPFD -- that
may be important for faulting instructions that also have a hardware
breakpoint set at their address.
> support in NMI handlers because of this limitation. This cannot be emulated
> with popf/lret, because lret would be single-stepped. It does not apply to
> "immediate values" because they do not use single-stepping. This code detects if
> the TF flag is set and uses the iret path for single-stepping, even if it
> reactivates NMIs prematurely.
What about the VM flag for VM86 tasks? It cannot be changed by POPFD
either.
How about only using the special return path when a nested exception is
about to return to the NMI handler? You'd avoid all the odd cases then
that do not happen in the NMI context.
Maciej
next prev parent reply other threads:[~2010-07-14 16:42 UTC|newest]
Thread overview: 168+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-14 15:49 [patch 0/2] x86: NMI-safe trap handlers Mathieu Desnoyers
2010-07-14 15:49 ` [patch 1/2] x86_64 page fault NMI-safe Mathieu Desnoyers
2010-07-14 16:28 ` Linus Torvalds
2010-07-14 17:06 ` Mathieu Desnoyers
2010-07-14 18:10 ` Linus Torvalds
2010-07-14 18:46 ` Ingo Molnar
2010-07-14 19:14 ` Linus Torvalds
2010-07-14 19:36 ` Frederic Weisbecker
2010-07-14 19:54 ` Linus Torvalds
2010-07-14 20:17 ` Mathieu Desnoyers
2010-07-14 20:55 ` Linus Torvalds
2010-07-14 21:18 ` Ingo Molnar
2010-07-14 22:14 ` Frederic Weisbecker
2010-07-14 22:31 ` Mathieu Desnoyers
2010-07-14 22:48 ` Frederic Weisbecker
2010-07-14 23:11 ` Mathieu Desnoyers
2010-07-14 23:38 ` Frederic Weisbecker
2010-07-15 16:26 ` Mathieu Desnoyers
2010-08-03 17:18 ` Peter Zijlstra
2010-08-03 18:25 ` Mathieu Desnoyers
2010-08-04 6:46 ` Peter Zijlstra
2010-08-04 7:14 ` Ingo Molnar
2010-08-04 14:45 ` Mathieu Desnoyers
2010-08-04 14:56 ` Peter Zijlstra
2010-08-06 1:49 ` Mathieu Desnoyers
2010-08-06 9:51 ` Peter Zijlstra
2010-08-06 13:46 ` Mathieu Desnoyers
2010-08-06 6:18 ` Masami Hiramatsu
2010-08-06 9:50 ` Peter Zijlstra
2010-08-06 13:37 ` Mathieu Desnoyers
2010-08-07 9:51 ` Masami Hiramatsu
2010-08-09 16:53 ` Frederic Weisbecker
2010-08-03 18:56 ` Linus Torvalds
2010-08-03 19:45 ` Mathieu Desnoyers
2010-08-03 20:02 ` Linus Torvalds
2010-08-03 20:10 ` Ingo Molnar
2010-08-03 20:21 ` Ingo Molnar
2010-08-03 21:16 ` Mathieu Desnoyers
2010-08-03 20:54 ` Mathieu Desnoyers
2010-08-04 6:27 ` Peter Zijlstra
2010-08-04 14:06 ` Mathieu Desnoyers
2010-08-04 14:50 ` Peter Zijlstra
2010-08-06 1:42 ` Mathieu Desnoyers
2010-08-06 10:11 ` Peter Zijlstra
2010-08-06 11:14 ` Peter Zijlstra
2010-08-06 14:15 ` Mathieu Desnoyers
2010-08-06 14:13 ` Mathieu Desnoyers
2010-08-11 14:44 ` Steven Rostedt
2010-08-11 14:34 ` Steven Rostedt
2010-08-15 13:35 ` Mathieu Desnoyers
2010-08-15 16:33 ` Avi Kivity
2010-08-15 16:44 ` Mathieu Desnoyers
2010-08-15 16:51 ` Avi Kivity
2010-08-15 18:31 ` Mathieu Desnoyers
2010-08-16 10:49 ` Avi Kivity
2010-08-16 11:29 ` Avi Kivity
2010-08-04 6:46 ` Dave Chinner
2010-08-04 7:21 ` Ingo Molnar
2010-07-14 23:40 ` Steven Rostedt
2010-07-14 19:41 ` Linus Torvalds
2010-07-14 19:56 ` Andi Kleen
2010-07-14 20:05 ` Mathieu Desnoyers
2010-07-14 20:07 ` Andi Kleen
2010-07-14 20:08 ` H. Peter Anvin
2010-07-14 23:32 ` Tejun Heo
2010-07-14 22:31 ` Frederic Weisbecker
2010-07-14 22:56 ` Linus Torvalds
2010-07-14 23:09 ` Andi Kleen
2010-07-14 23:22 ` Linus Torvalds
2010-07-15 14:11 ` Frederic Weisbecker
2010-07-15 14:35 ` Andi Kleen
2010-07-16 11:21 ` Frederic Weisbecker
2010-07-15 14:46 ` Steven Rostedt
2010-07-16 10:47 ` Frederic Weisbecker
2010-07-16 11:43 ` Steven Rostedt
2010-07-15 14:51 ` Linus Torvalds
2010-07-15 15:38 ` Linus Torvalds
2010-07-16 12:00 ` Frederic Weisbecker
2010-07-16 12:54 ` Steven Rostedt
2010-07-14 20:39 ` Mathieu Desnoyers
2010-07-14 21:23 ` Linus Torvalds
2010-07-14 21:45 ` Maciej W. Rozycki
2010-07-14 21:52 ` Linus Torvalds
2010-07-14 22:31 ` Maciej W. Rozycki
2010-07-14 22:21 ` Mathieu Desnoyers
2010-07-14 22:37 ` Linus Torvalds
2010-07-14 22:51 ` Jeremy Fitzhardinge
2010-07-14 23:02 ` Linus Torvalds
2010-07-14 23:54 ` Jeremy Fitzhardinge
2010-07-15 1:23 ` Linus Torvalds
2010-07-15 1:45 ` Linus Torvalds
2010-07-15 18:31 ` Mathieu Desnoyers
2010-07-15 18:43 ` Linus Torvalds
2010-07-15 18:48 ` Linus Torvalds
2010-07-15 22:01 ` Mathieu Desnoyers
2010-07-15 22:16 ` Linus Torvalds
2010-07-15 22:24 ` H. Peter Anvin
2010-07-15 22:26 ` Linus Torvalds
2010-07-15 22:46 ` H. Peter Anvin
2010-07-15 22:58 ` Andi Kleen
2010-07-15 23:20 ` H. Peter Anvin
2010-07-15 23:23 ` Linus Torvalds
2010-07-15 23:41 ` H. Peter Anvin
2010-07-15 23:44 ` Linus Torvalds
2010-07-15 23:46 ` H. Peter Anvin
2010-07-15 23:48 ` Andi Kleen
2010-07-15 22:30 ` Mathieu Desnoyers
2010-07-16 19:13 ` Mathieu Desnoyers
2010-07-15 16:44 ` Mathieu Desnoyers
2010-07-15 16:49 ` Linus Torvalds
2010-07-15 17:38 ` Mathieu Desnoyers
2010-07-15 20:44 ` H. Peter Anvin
2010-07-18 11:03 ` Avi Kivity
2010-07-18 17:36 ` Linus Torvalds
2010-07-18 18:04 ` Avi Kivity
2010-07-18 18:22 ` Linus Torvalds
2010-07-19 7:32 ` Avi Kivity
2010-07-18 18:17 ` Linus Torvalds
2010-07-18 18:43 ` Steven Rostedt
2010-07-18 19:26 ` Linus Torvalds
2010-07-14 15:49 ` [patch 2/2] x86 NMI-safe INT3 and Page Fault Mathieu Desnoyers
2010-07-14 16:42 ` Maciej W. Rozycki [this message]
2010-07-14 18:12 ` Mathieu Desnoyers
2010-07-14 19:21 ` Maciej W. Rozycki
2010-07-14 19:58 ` Mathieu Desnoyers
2010-07-14 20:36 ` Maciej W. Rozycki
2010-07-16 12:28 ` Avi Kivity
2010-07-16 14:49 ` Mathieu Desnoyers
2010-07-16 15:34 ` Andi Kleen
2010-07-16 15:40 ` Mathieu Desnoyers
2010-07-16 16:47 ` Avi Kivity
2010-07-16 16:58 ` Mathieu Desnoyers
2010-07-16 17:54 ` Avi Kivity
2010-07-16 18:05 ` H. Peter Anvin
2010-07-16 18:15 ` Avi Kivity
2010-07-16 18:17 ` H. Peter Anvin
2010-07-16 18:28 ` Avi Kivity
2010-07-16 18:37 ` Linus Torvalds
2010-07-16 19:26 ` Avi Kivity
2010-07-16 21:39 ` Linus Torvalds
2010-07-16 22:07 ` Andi Kleen
2010-07-16 22:26 ` Linus Torvalds
2010-07-16 22:41 ` Andi Kleen
2010-07-17 1:15 ` Linus Torvalds
2010-07-16 22:40 ` Mathieu Desnoyers
2010-07-18 9:23 ` Avi Kivity
2010-07-16 18:22 ` Mathieu Desnoyers
2010-07-16 18:32 ` Avi Kivity
2010-07-16 19:29 ` H. Peter Anvin
2010-07-16 19:39 ` Avi Kivity
2010-07-16 19:32 ` Andi Kleen
2010-07-16 18:25 ` Linus Torvalds
2010-07-16 19:30 ` Andi Kleen
2010-07-18 9:26 ` Avi Kivity
2010-07-16 19:28 ` Andi Kleen
2010-07-16 19:32 ` Avi Kivity
2010-07-16 19:34 ` Andi Kleen
2010-08-04 9:46 ` Peter Zijlstra
2010-08-04 20:23 ` H. Peter Anvin
2010-07-14 17:06 ` [patch 0/2] x86: NMI-safe trap handlers Andi Kleen
2010-07-14 17:08 ` Mathieu Desnoyers
2010-07-14 18:56 ` Andi Kleen
2010-07-14 23:29 ` Tejun Heo
2010-07-16 22:02 [patch 2/2] x86 NMI-safe INT3 and Page Fault Jeffrey Merkey
2010-07-16 22:22 ` Linus Torvalds
2010-07-16 22:48 ` Jeffrey Merkey
2010-07-16 22:53 ` Jeffrey Merkey
2010-07-16 22:50 ` Jeffrey Merkey
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