From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758596AbYFSOcS (ORCPT ); Thu, 19 Jun 2008 10:32:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752139AbYFSOcG (ORCPT ); Thu, 19 Jun 2008 10:32:06 -0400 Received: from vpn.id2.novell.com ([195.33.99.129]:31473 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751945AbYFSOcF convert rfc822-to-8bit (ORCPT ); Thu, 19 Jun 2008 10:32:05 -0400 Message-Id: <485A8A16.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 7.0.3 Date: Thu, 19 Jun 2008 15:32:22 +0100 From: "Jan Beulich" To: "Ingo Molnar" , "Andi Kleen" Cc: "the arch/x86 maintainers" , , , Subject: Re: [PATCH] x86-64: remove unnecessary ptregs call stubs References: <485910B3.76E4.0078.0@novell.com> <20080619122538.GH7640@elte.hu> <485A5606.6080600@firstfloor.org> In-Reply-To: <485A5606.6080600@firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> Andi Kleen 19.06.08 14:50 >>> >Ingo Molnar wrote: >> * Jan Beulich wrote: >> >>> A few of the ptregs call stubs are superfluous these days - the called >>> functions don't have a trailing 'struct pt_regs *' parameter anymore. >> >> applied to tip/x86/cleanups - thanks Jan. > >Just want to point out that not having a pt_regs * argument is not necessarily >sufficient for not needing a ptregs stub. Some code also accesses ptregs directly >through the stack top from get_thread_info() and might assume a full one. That said I *think* >it's ok for sigsuspend et.al. as in Jan's patch, but I haven't audited the complete code paths >in question that they never do that. > >Would be good to clarify that in the commit log. Looking at both the source and disassembly of sys_rt_sigsuspend() and sys32_sigsuspend(), I cannot see anything pt_regs related. All these functions call are copy_from_user(), spin_lock_irq(), recalc_sigpending(), and schedule(), and besides that they just update some global and task state. Jan