From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752895AbZB1HP5 (ORCPT ); Sat, 28 Feb 2009 02:15:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751374AbZB1HPs (ORCPT ); Sat, 28 Feb 2009 02:15:48 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:57383 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbZB1HPs (ORCPT ); Sat, 28 Feb 2009 02:15:48 -0500 Date: Sat, 28 Feb 2009 08:15:34 +0100 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Yinghai Lu , "H. Peter Anvin" , the arch/x86 maintainers , Linux Kernel Mailing List , Jeremy Fitzhardinge Subject: Re: J Message-ID: <20090228071534.GB9351@elte.hu> References: <1235785882-17580-1-git-send-email-jeremy@goop.org> <1235785882-17580-4-git-send-email-jeremy@goop.org> <86802c440902272302n3787b2bex3741b46a372a19b0@mail.gmail.com> <49A8E235.6010900@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49A8E235.6010900@goop.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean 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=3.2.3 -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 * Jeremy Fitzhardinge wrote: > Yinghai Lu wrote: >> On Fri, Feb 27, 2009 at 5:51 PM, Jeremy Fitzhardinge wrote: >> >>> From: Jeremy Fitzhardinge >>> >>> Rather than having special purpose init_pg_table_start/end variables >>> to delimit the kernel pagetable built by head_32.S, just use the brk >>> mechanism to extend the bss for the new pagetable. >>> >>> This patch removes init_pg_table_start/end and pg0, defines __brk_base >>> (which is page-aligned and immediately follows _end), initializes >>> the brk region to start there, and uses it for the 32-bit pagetable. >>> >> ... >> >> >>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c >>> index c246dc4..ed02176 100644 >>> --- a/arch/x86/kernel/setup.c >>> +++ b/arch/x86/kernel/setup.c >>> @@ -113,8 +113,10 @@ >>> #endif >>> >>> unsigned int boot_cpu_id __read_mostly; >>> -__initdata unsigned long _brk_start = (unsigned long)&_end; >>> -__initdata unsigned long _brk_end = (unsigned long)&_end; >>> + >>> +extern char __brk_base[]; >>> +__initdata unsigned long _brk_start = (unsigned long)__brk_base; >>> +__initdata unsigned long _brk_end = (unsigned long)&__brk_base; >>> >> >> ? >> > > What are you asking? __brk_base is _end rounded up to a page > boundary, so head_32.S can use it directly for pagetable > allocation. Are you flagging the '&' typo? Something else? it's not really a typo either (__brk_base and &__brk_base should be the same) - just a bit weird looking. Ingo