Date: Fri, 25 Sep 2009 12:14:49 +0200
From: Arjan van de Ven <arjan@infradead.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
       Jason Baron <jbaron@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
       Steven Rostedt <rostedt@goodmis.org>, Andi Kleen <ak@suse.de>,
       linux-kernel@vger.kernel.org, Masami Hiramatsu <mhiramat@redhat.com>,
       Prasanna S Panchamukhi <prasanna@in.ibm.com>,
       Rusty Lynch <rusty.lynch@intel.com>, Jim Keniston <jkenisto@us.ibm.com>,
       Vamsi Krishna S <vamsi_krishna@in.ibm.com>,
       Suparna Bhattacharya <suparna@in.ibm.com>,
       Nathan Sidwell <nathan@codesourcery.com>,
       Dominique Toupin <dominique.toupin@ericsson.com>,
       Anton Massoud <anton.massoud@ericsson.com>,
       Richard J Moore <richardj_moore@uk.ibm.com>
Subject: Re: Immediate values
Message-ID: <20090925121449.7bb27b61@infradead.org>
In-Reply-To: <20090925110206.50ab8a20@lxorguk.ukuu.org.uk>
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	<20090924193422.GB2533@elte.hu>
	<20090925085119.2b77ea04@infradead.org>
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	<20090925110206.50ab8a20@lxorguk.ukuu.org.uk>
Organization: Intel
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On Fri, 25 Sep 2009 11:02:06 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> > Then, following your advice, kprobes should be re-designed to do a
> > stop_machine around the int3 breakpoint insertion ? And gdb
> > should be stopping all threads of a target process before inserting
> > a breakpoint. Therefore, I do not seem to be the only one confused
> > about Intel statement on this issue.
> 
> There was considerable discussion abut this when the kprobe stuff went
> in. If I remember rightly it was stated by someone @intel.com then
> that int3 was ok (even though its not strictly documented as such).
> The same is not true for all instructions on all x86 processors
> unfortunately.

specifically, using int3 *and then going back to the old value*.


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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