From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753257AbXCRRER (ORCPT ); Sun, 18 Mar 2007 13:04:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753261AbXCRRER (ORCPT ); Sun, 18 Mar 2007 13:04:17 -0400 Received: from colin.muc.de ([193.149.48.1]:3879 "EHLO mail.muc.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753257AbXCRREQ (ORCPT ); Sun, 18 Mar 2007 13:04:16 -0400 Date: 18 Mar 2007 18:04:14 +0100 Date: Sun, 18 Mar 2007 18:04:14 +0100 From: Andi Kleen To: Jeremy Fitzhardinge Cc: David Miller , rusty@rustcorp.com.au, mingo@elte.hu, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, chrisw@sous-sol.org, zach@vmware.com, anthony@codemonkey.ws, torvalds@linux-foundation.org, netdev@vger.kernel.org Subject: Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable Message-ID: <20070318170414.GB45869@muc.de> References: <20070316.023331.59468179.davem@davemloft.net> <45FB005D.9060809@goop.org> <1174127638.8897.75.camel@localhost.localdomain> <20070318.003309.71088169.davem@davemloft.net> <20070318120814.GA45869@muc.de> <45FD619D.6030402@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45FD619D.6030402@goop.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > The bigger problem is that you don't know what registers you can > clobber. For the pv_ops in hand-written asm, that a big pain. The code > either has to assume the worst, or the "relocator" has to do something > more sophisticated (like look for push/pop pairs surrounding the call, > perhaps?). You could use the dwarf2 unwind tables. They have exact information what register has what. But it would likely get complicated. -Andi