From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752498AbeBJVUP (ORCPT ); Sat, 10 Feb 2018 16:20:15 -0500 Received: from mx2.suse.de ([195.135.220.15]:49300 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751145AbeBJVUO (ORCPT ); Sat, 10 Feb 2018 16:20:14 -0500 Date: Sat, 10 Feb 2018 22:19:46 +0100 From: Borislav Petkov To: Alexey Dobriyan Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86_64: clobber flags in clear_page() Message-ID: <20180210211945.GA21424@pd.tnic> References: <20180113185048.GA23111@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180113185048.GA23111@avx2> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 13, 2018 at 09:50:48PM +0300, Alexey Dobriyan wrote: > All clear_page() implementations use XOR which resets flags. > > Judging by allyesconfig disassembly no code is affected. > > Signed-off-by: Alexey Dobriyan > --- > > arch/x86/include/asm/page_64.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/arch/x86/include/asm/page_64.h > +++ b/arch/x86/include/asm/page_64.h > @@ -47,7 +47,7 @@ static inline void clear_page(void *page) > clear_page_erms, X86_FEATURE_ERMS, > "=D" (page), > "0" (page) > - : "memory", "rax", "rcx"); > + : "cc", "memory", "rax", "rcx"); > } > > void copy_page(void *to, void *from); Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --