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Date: Tue, 17 Feb 2009 12:28:50 -0500
From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>, Nick Piggin <npiggin@suse.de>,
       Peter Zijlstra <peterz@infradead.org>, akpm <akpm@linux-foundation.org>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       Ingo Molnar <mingo@elte.hu>,
       Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
       Jim Keniston <jkenisto@us.ibm.com>
Subject: Re: irq-disabled vs vmap vs text_poke
Message-ID: <20090217172850.GB14435@Krystal>
References: <4995E925.3080506@redhat.com> <4999808B.5080505@redhat.com> <20090216153145.GB19182@wotan.suse.de> <20090216172441.GA12576@Krystal> <499A1A43.6000009@redhat.com> <20090217030353.GA31504@wotan.suse.de> <499AEA72.9090702@redhat.com> <alpine.DEB.1.10.0902171158180.910@gandalf.stny.rr.com> <20090217171845.GA14435@Krystal> <alpine.DEB.1.10.0902171224050.910@gandalf.stny.rr.com>
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* Steven Rostedt (rostedt@goodmis.org) wrote:
> 
> On Tue, 17 Feb 2009, Mathieu Desnoyers wrote:
> > > 
> > 
> > Anyway dynamic ftrace only need to do code patching at early boot,
> > right? Or do you need also to patch the call sites a bit later too ?
> > Because there is a text_poke_early for that purpose : modifying code
> > when it is still writable.
> 
> It modifies the code both at early boot up, and when it is enabled later 
> on at run time.
> 
> -- Steve
> 

OK, so without text_poke, how does it deal with kernel with text pages
marked read-only after boot ?

Mathieu


-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68