Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759892AbZCBSgm (ORCPT ); Mon, 2 Mar 2009 13:36:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754146AbZCBSgY (ORCPT ); Mon, 2 Mar 2009 13:36:24 -0500 Received: from tomts13.bellnexxia.net ([209.226.175.34]:49785 "EHLO tomts13-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758048AbZCBSgW (ORCPT ); Mon, 2 Mar 2009 13:36:22 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AhIFALO0q0lMQW1W/2dsb2JhbACBWdRAhBoG Date: Mon, 2 Mar 2009 13:36:17 -0500 From: Mathieu Desnoyers To: Arjan van de Ven Cc: Masami Hiramatsu , Ingo Molnar , Andrew Morton , Nick Piggin , Steven Rostedt , Andi Kleen , linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Frederic Weisbecker , Linus Torvalds , Rusty Russell , "H. Peter Anvin" , Steven Rostedt Subject: Re: [RFC][PATCH] x86: make text_poke() atomic Message-ID: <20090302183617.GA25105@Krystal> References: <20090223173108.GB1441@Krystal> <49A82851.5080707@redhat.com> <20090227180724.GA17947@Krystal> <49A83237.40604@redhat.com> <20090227185316.GA19811@Krystal> <49A853CD.3020607@redhat.com> <49AC10E9.1090102@redhat.com> <20090302102841.7e099670@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20090302102841.7e099670@infradead.org> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 13:34:57 up 2 days, 15:01, 3 users, load average: 0.72, 0.55, 0.39 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1062 Lines: 30 * Arjan van de Ven (arjan@infradead.org) wrote: > > > > Use map_vm_area() instead of vmap() in text_poke() for avoiding page > > allocation and delayed unmapping, and call vunmap_page_range() and > > local_flush_tlb() directly because this mapping is temporary and > > local. > > > > At the result of above change, text_poke() becomes atomic and can be > > called from stop_machine() etc. > > .... but text_poke() realistically needs to call stop_machine() since > you can't poke live code.... so that makes me wonder how useful this > is... Hi Arjan, Stop machine is not required when inserting a breakpoint. And cleverly using this breakpoint technique can permit modifying other instructions as well. Mathieu -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/