From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932472AbZHUQEp (ORCPT ); Fri, 21 Aug 2009 12:04:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932297AbZHUQEo (ORCPT ); Fri, 21 Aug 2009 12:04:44 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:51854 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932274AbZHUQEo (ORCPT ); Fri, 21 Aug 2009 12:04:44 -0400 Date: Fri, 21 Aug 2009 18:04:26 +0200 From: Ingo Molnar To: Cyrill Gorcunov Cc: "H. Peter Anvin" , Thomas Gleixner , LKML Subject: Re: [PATCH -tip] x86: smp_scan_config - use signed long as scan area size Message-ID: <20090821160426.GA17731@elte.hu> References: <20090820173427.GA8517@lenovo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090820173427.GA8517@lenovo> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Cyrill Gorcunov wrote: > Unsigned value potentially could be overlapped > if length parameter is that: length % 16 != 0. > > This is not a problem at moment since all values > we pass now are 16 divisible (0x400 and 0x10000). > > Though there is no need unsigned value anyway. > Max range pointed out by MP specification is > in kilobytes so plain "signed long" is enough. > > This allow us to be on a safe side. > > Signed-off-by: Cyrill Gorcunov > --- > > (I doubt if we ever will need to scan 1G of physical > memory with 16 byte step at booting procedure 'xcept > memtest case) > > Please review. Not sure if the patch is that worth > but anyway :) > > arch/x86/kernel/mpparse.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6.git/arch/x86/kernel/mpparse.c > ===================================================================== > --- linux-2.6.git.orig/arch/x86/kernel/mpparse.c > +++ linux-2.6.git/arch/x86/kernel/mpparse.c > @@ -705,7 +705,7 @@ static void __init smp_reserve_bootmem(s > #endif > } > > -static int __init smp_scan_config(unsigned long base, unsigned long length, > +static int __init smp_scan_config(unsigned long base, long length, > unsigned reserve) > { > unsigned int *bp = phys_to_virt(base); Hm, does a BUILD_BUG_ON((length & 15) != 0) line catch incorrectly aligned length parameters? Ingo