From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753077AbZB1Hbx (ORCPT ); Sat, 28 Feb 2009 02:31:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751407AbZB1Hbp (ORCPT ); Sat, 28 Feb 2009 02:31:45 -0500 Received: from hera.kernel.org ([140.211.167.34]:59583 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387AbZB1Hbo (ORCPT ); Sat, 28 Feb 2009 02:31:44 -0500 Message-ID: <49A8E830.1090202@kernel.org> Date: Fri, 27 Feb 2009 23:30:56 -0800 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: "H. Peter Anvin" , the arch/x86 maintainers , Linux Kernel Mailing List , Jeremy Fitzhardinge Subject: Re: J 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> In-Reply-To: <49A8E235.6010900@goop.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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? why start don't have &, but end has & YH