Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758704AbZGCUsv (ORCPT ); Fri, 3 Jul 2009 16:48:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756365AbZGCUso (ORCPT ); Fri, 3 Jul 2009 16:48:44 -0400 Received: from mx-out.daemonmail.net ([216.104.160.38]:43737 "EHLO mx-out.daemonmail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756083AbZGCUsn convert rfc822-to-8bit (ORCPT ); Fri, 3 Jul 2009 16:48:43 -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 15:48:39 -0500 User-Agent: KMail/1.9.9 Cc: linux-kernel@vger.kernel.org References: <200907031314.36243.lkml@morethan.org> <86802c440907031307s43fca3c0j77d4df78450ff757@mail.gmail.com> <86802c440907031308j3f996db6g9dfb1b8f9ccb7e7f@mail.gmail.com> In-Reply-To: <86802c440907031308j3f996db6g9dfb1b8f9ccb7e7f@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200907031548.42690.lkml@morethan.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2690 Lines: 75 On Fri July 3 2009, Yinghai Lu wrote: > On Fri, Jul 3, 2009 at 1:07 PM, 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. > > > > please send out whole dmesg. with and without your patch. it could > > 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 > > > mean > Yes, want to get the 8K page machines correct also. > > >> /* 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<<(32 - PAGE_SHIFT)) - (__PAGE_OFFSET >> PAGE_SHIFT)) << PAGE_SHIFT > You read my mind, thanks. Mike > YH > -- > 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/ > > -- 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/