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From: Steven Rostedt <rostedt@goodmis.org>
To: Jiri Kosina <jkosina@suse.cz>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Jason Baron <jbaron@akamai.com>, Borislav Petkov <bp@alien8.de>,
	Joe Perches <joe@perches.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2 v3] x86: introduce int3-based instruction patching
Date: Thu, 11 Jul 2013 22:09:08 -0400	[thread overview]
Message-ID: <1373594948.17876.77.camel@gandalf.local.home> (raw)
In-Reply-To: <alpine.LNX.2.00.1307120027570.29788@pobox.suse.cz>

On Fri, 2013-07-12 at 00:31 +0200, Jiri Kosina wrote:
> On Thu, 11 Jul 2013, H. Peter Anvin wrote:
> 
> > > synchronization after replacing "all but first" instructions should not
> > > be necessary (on Intel hardware), as the syncing after the subsequent
> > > patching of the first byte provides enough safety.
> > > But there's not only Intel HW out there, and we'd rather be on a safe
> > > side.
> > 
> > Has anyone talked to AMD or VIA about this at all?  Did anyone else ever
> > make SMP-capable x86?
> 
> If Boris can verify for AMD, that'd be good; we could then just remove one 
> extra syncing of the cores as a followup (can be done any time later, both 
> for alternative.c and ftrace in fact).
> 
> With the "extra" sync, the procedure is already verified to work properly 
> by ftace.
> 

I'd like to caution on the side of safety. The extra sync really doesn't
hurt. Let's keep it in for a kernel release cycle to make sure
everything else works properly, then we can look at optimizing it.

-- Steve



  reply	other threads:[~2013-07-12  2:09 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-10 20:25 [RFC] [PATCH 0/2] x86: make jump labels use int3-based breakpoint instead of stop_machine() Jiri Kosina
2013-07-10 20:25 ` [RFC] [PATCH 1/2] x86: introduce int3-based instruction patching Jiri Kosina
2013-07-10 21:31   ` [RFC] [PATCH 1/2 v2] " Jiri Kosina
2013-07-10 21:36     ` H. Peter Anvin
2013-07-10 21:48       ` Borislav Petkov
2013-07-10 21:56         ` H. Peter Anvin
2013-07-10 22:14           ` Borislav Petkov
2013-07-10 22:39       ` Jiri Kosina
2013-07-11  3:29       ` Masami Hiramatsu
2013-07-11 10:09       ` Jiri Kosina
2013-07-11 10:54         ` Jiri Kosina
2013-07-11 16:31         ` H. Peter Anvin
2013-07-11 16:46           ` Steven Rostedt
2013-07-11 19:21             ` Jiri Kosina
2013-07-12  1:00             ` Masami Hiramatsu
2013-07-11 14:35       ` Steven Rostedt
2013-07-11 14:47         ` Jason Baron
2013-07-10 21:46     ` Joe Perches
2013-07-11 10:23     ` Masami Hiramatsu
2013-07-11 10:51       ` Jiri Kosina
2013-07-12  0:50         ` Masami Hiramatsu
2013-07-11 16:10       ` H. Peter Anvin
2013-07-11 19:29         ` Jiri Kosina
2013-07-11 20:49           ` H. Peter Anvin
2013-07-11 20:51           ` H. Peter Anvin
2013-07-11 15:57     ` Steven Rostedt
2013-07-11 19:43       ` Jiri Kosina
2013-07-11 19:52         ` Steven Rostedt
2013-07-10 20:25 ` [RFC] [PATCH 2/2] x86: make jump_label use int3-based patching Jiri Kosina
2013-07-10 22:26 ` [RFC] [PATCH 0/2] x86: make jump labels use int3-based breakpoint instead of stop_machine() Jason Baron
2013-07-11  0:04   ` Jiri Kosina
2013-07-11 16:42     ` Steven Rostedt
2013-07-11 19:23       ` Jiri Kosina
2013-07-11 19:54         ` Steven Rostedt
2013-07-11  2:21 ` Masami Hiramatsu
2013-07-11 20:26 ` [PATCH 2/2 v3] x86: make jump_label use int3-based patching Jiri Kosina
2013-07-12  2:12   ` Steven Rostedt
2013-07-12  5:44   ` Masami Hiramatsu
2013-07-11 20:26 ` [PATCH 1/2 v3] x86: introduce int3-based instruction patching Jiri Kosina
2013-07-11 20:53   ` H. Peter Anvin
2013-07-11 21:04     ` Borislav Petkov
2013-07-11 21:36       ` H. Peter Anvin
2013-07-12  7:57         ` Borislav Petkov
2013-07-17  3:59           ` H. Peter Anvin
2013-07-11 22:31     ` Jiri Kosina
2013-07-12  2:09       ` Steven Rostedt [this message]
2013-07-11 23:01   ` Joe Perches
2013-07-12  2:07   ` Steven Rostedt
2013-07-12  2:40   ` Masami Hiramatsu
2013-07-12  9:21 ` [PATCH 1/2 v4] " Jiri Kosina
2013-07-17  1:18   ` [tip:x86/jumplabel] x86: Introduce int3 (breakpoint) -based " tip-bot for Jiri Kosina
2013-07-12  9:22 ` [PATCH 2/2 v4] x86: make jump_label use int3-based patching Jiri Kosina
2013-07-17  1:18   ` [tip:x86/jumplabel] x86: Make " tip-bot for Jiri Kosina

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