Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758839AbZGCUpv (ORCPT ); Fri, 3 Jul 2009 16:45:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757077AbZGCUpo (ORCPT ); Fri, 3 Jul 2009 16:45:44 -0400 Received: from mx-out2.daemonmail.net ([216.104.160.39]:56037 "EHLO mx-out2.daemonmail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755660AbZGCUpn convert rfc822-to-8bit (ORCPT ); Fri, 3 Jul 2009 16:45:43 -0400 From: "Michael S. Zick" Reply-To: lkml@morethan.org To: Yinghai Lu Subject: Re: [Bug Fix]: Do 32-bit table calculations in pre-processor Date: Fri, 3 Jul 2009 15:45:42 -0500 User-Agent: KMail/1.9.9 Cc: linux-kernel@vger.kernel.org References: <200907031314.36243.lkml@morethan.org> <86802c440907031307s43fca3c0j77d4df78450ff757@mail.gmail.com> In-Reply-To: <86802c440907031307s43fca3c0j77d4df78450ff757@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200907031545.45124.lkml@morethan.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2168 Lines: 66 On Fri July 3 2009, Yinghai Lu wrote: > On Fri, Jul 3, 2009 at 11:14 AM, Michael S. Zick wrote: > > Here is one I have found useful in my VIA processor bug hunting: > > > > diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S > > index 3068388..2303d86 100644 > > --- a/arch/x86/kernel/head_32.S > > +++ b/arch/x86/kernel/head_32.S > > @@ -61,7 +61,7 @@ > > > > ?/* Enough space to fit pagetables for the low memory linear map */ > > ?MAPPING_BEYOND_END = \ > > - ? ? ? PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT > > + ? ? ? PAGE_TABLE_SIZE((1<<20) - (__PAGE_OFFSET >> PAGE_SHIFT)) << PAGE_SHIFT > > > > ?/* > > ?* Worst-case size of the kernel mapping we need to make: > > > > = = = > > > > Before: > > > > ?#5 [0000010000 - 0000011000] ? ? ? ? ?PGTABLE ==> [0000010000 - 0000011000] > > ?#6 [0000011000 - 0000015000] ? ? ? ? ?BOOTMAP ==> [0000011000 - 0000015000] > > > > After: > > > > ?#5 [0000010000 - 000007d000] ? ? ? ? ?PGTABLE ==> [0000010000 - 000007d000] > > ?#6 [000007d000 - 0000081000] ? ? ? ? ?BOOTMAP ==> [000007d000 - 0000081000] > > > > that PGTABLE is from early resource. and it is filled by init_memory_mapping() > > it mean preallocated pgtable to MAPPING_BEYOND_END is small now after > patch. and init_memory_mapping try to get more. > Ah, so - the labels are a bit misleading - but that makes since. > please send out whole dmesg. with and without your patch. it could > Am having technical problems at the moment - maybe later today I can get you the information you need. > print out initial mapped before e820 allocation is involved for 32bit > printk(KERN_DEBUG "initial memory mapped : 0 - %08lx\n", > max_pfn_mapped< > > > your patch should be right. except to change that 12 to PAGE_SHIFT > Not all pages are 4K, but as you point out, that can be fixed. > YH > > Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/