From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755267AbZBCNKf (ORCPT ); Tue, 3 Feb 2009 08:10:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753632AbZBCNKF (ORCPT ); Tue, 3 Feb 2009 08:10:05 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:50774 "EHLO gprs189-60.eurotel.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753348AbZBCNKE (ORCPT ); Tue, 3 Feb 2009 08:10:04 -0500 Date: Fri, 30 Jan 2009 22:06:25 +0100 From: Pavel Machek To: Jeremy Fitzhardinge Cc: Zachary Amsden , "H. Peter Anvin" , Ian Campbell , Ingo Molnar , Linux Kernel Mailing List Subject: Re: [PATCH RFC WIP] x86/paravirt: add register-saving thunks to reduce caller register pressure Message-ID: <20090130210625.GD1253@ucw.cz> References: <4980A07D.3010008@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4980A07D.3010008@goop.org> 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 > This patch seeks to alleviate this pressure by introducing wrapper > thunks that will do the register saving/restoring, so that the > callsite doesn't need to worry about it, but the callee function can > be conventional compiler-generated code. In many cases (particularly > performance-sensitive cases) the callee will be in assembler anyway, > and need not use the compiler's calling convention. > > Standard calling convention is: > arguments return scratch > x86-32 eax edx ecx eax ? esi edi ebp ? actually standard calling convention is all arguments on stack iirc but we use regparm=3 for kernel...? -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html