From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755465Ab2BUO0M (ORCPT ); Tue, 21 Feb 2012 09:26:12 -0500 Received: from nat28.tlf.novell.com ([130.57.49.28]:26685 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752921Ab2BUO0K convert rfc822-to-8bit (ORCPT ); Tue, 21 Feb 2012 09:26:10 -0500 Message-Id: <4F43B78D020000780007435B@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Tue, 21 Feb 2012 14:26:05 +0000 From: "Jan Beulich" To: "Mark Wielaard" Cc: "Frederic Weisbecker (commit_signer:4/25=16%)" , "maintainer:X86 ARCHITECTURE..." , "Thomas Gleixner (maintainer:X86 ARCHITECTURE...)" , "Andi Kleen (commit_signer:5/25=20%)" , "commit_signer:11/25=44%) Ingo Molnar (maintainer:X86 ARCHITECTURE..." , , "commit_signer:4/25=16%) H. Peter Anvin (maintainer:X86 ARCHITECTURE..." Subject: Re: [PATCH] x86-64: Fix CFI data for common_interrupt References: <1329833177-13030-1-git-send-email-mjw@redhat.com> In-Reply-To: <1329833177-13030-1-git-send-email-mjw@redhat.com> 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 >>> On 21.02.12 at 15:06, Mark Wielaard wrote: > Commit eab9e6 "x86-64: Fix CFI data for interrupt frames" introduced > a DW_CFA_def_cfa_expression in the SAVE_ARGS_IRQ macro. To later define > the CFA using a simple register+offset rule both register and offset > need to be supplied. Just using CFI_DEF_CFA_REGISTER leaves the offset > undefined. So use CFI_DEF_CFA with reg+off explicitly at the end of > common_interrupt. NAK, unless you can prove a path via which the offset will remain unset until hitting a CFI_DEF_CFA_REGISTER. And if you indeed found such a path, the entry point of the path is where the problem ought to be fixed. Are you perhaps thinking that .cfi_def_cfa_register invalidates the offset in any way? That, to my knowledge, isn't the case, it just replaces the CFA register with the one specified, leaving the offset unchanged. Jan > Signed-off-by: Mark Wielaard > --- > arch/x86/kernel/entry_64.S | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S > index 3fe8239..e00ef55 100644 > --- a/arch/x86/kernel/entry_64.S > +++ b/arch/x86/kernel/entry_64.S > @@ -813,7 +813,7 @@ ret_from_intr: > > /* Restore saved previous stack */ > popq %rsi > - CFI_DEF_CFA_REGISTER rsi > + CFI_DEF_CFA rsi,0 /* needed after def_cfa_expression */ > leaq ARGOFFSET-RBP(%rsi), %rsp > CFI_DEF_CFA_REGISTER rsp > CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET > -- > 1.7.7.6