From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753109AbZHXRkP (ORCPT ); Mon, 24 Aug 2009 13:40:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753065AbZHXRkO (ORCPT ); Mon, 24 Aug 2009 13:40:14 -0400 Received: from hera.kernel.org ([140.211.167.34]:58843 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752936AbZHXRkN (ORCPT ); Mon, 24 Aug 2009 13:40:13 -0400 Message-ID: <4A92D029.8090807@kernel.org> Date: Mon, 24 Aug 2009 10:38:49 -0700 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.22 (X11/20090605) MIME-Version: 1.0 To: Hugh Dickins , Ingo Molnar , Linus Torvalds , Zachary Amsden , "H. Peter Anvin" CC: Xiao Guangrong , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: linux-next: reservetop fix disables mem= References: In-Reply-To: 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 Hugh Dickins wrote: > I find the "mem=" boot parameter disabled in today's linux-next: > reverting the tip commit below fixes that. > > Hugh > > From: Xiao Guangrong > Date: Thu, 20 Aug 2009 12:23:11 +0000 (+0800) > Subject: x86: Fix system crash when loading with "reservetop" parameter > X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fmingo%2Flinux-2.6-x86.git;a=commitdiff_plain;h=8126dec32738421afa362114337331337b4be17f > > x86: Fix system crash when loading with "reservetop" parameter > > The system will die if the kernel is booted with "reservetop" > parameter, in present code, parse "reservetop" parameter after > early_ioremap_init(), and some function still use > early_ioremap() after it. > > The problem is, "reservetop" parameter can modify > 'FIXADDR_TOP', then the virtual address got by early_ioremap() > is base on old 'FIXADDR_TOP', but the page mapping is base on > new 'FIXADDR_TOP', it will occur page fault, and the IDT is not > prepare yet, so, the system is dead. > > So, put parse_early_param() in the front of > early_ioremap_init() in this patch. > > Signed-off-by: Xiao Guangrong > Cc: yinghai@kernel.org > Cc: Andrew Morton > LKML-Reference: <4A8D402F.4080805@cn.fujitsu.com> > Signed-off-by: Ingo Molnar > --- > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index 63f32d2..02643cc 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -711,6 +711,11 @@ void __init setup_arch(char **cmdline_p) > printk(KERN_INFO "Command line: %s\n", boot_command_line); > #endif > > + strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > + *cmdline_p = command_line; > + > + parse_early_param(); > + > /* VMI may relocate the fixmap; do this before touching ioremap area */ > vmi_init(); > > @@ -793,11 +798,6 @@ void __init setup_arch(char **cmdline_p) > #endif > #endif > > - strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > - *cmdline_p = command_line; > - > - parse_early_param(); > - > #ifdef CONFIG_X86_64 > check_efer(); > #endif yes, that patch will break other built-in command too. need drop that patch. also the problem was caused by vmi patch, and that commit should be reverted. commit ae8d04e2ecbb233926860e9ce145eac19c7835dc Author: Zachary Amsden Date: Sat Dec 13 12:36:58 2008 -0800 x86 Fix VMI crash on boot in 2.6.28-rc8 VMI initialiation can relocate the fixmap, causing early_ioremap to malfunction if it is initialized before the relocation. To fix this, VMI activation is split into two phases; the detection, which must happen before setting up ioremap, and the activation, which must happen after parsing early boot parameters. This fixes a crash on boot when VMI is enabled under VMware. Signed-off-by: Zachary Amsden Signed-off-by: Linus Torvalds diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 9d5674f..bdec76e 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -794,6 +794,9 @@ void __init setup_arch(char **cmdline_p) printk(KERN_INFO "Command line: %s\n", boot_command_line); #endif + /* VMI may relocate the fixmap; do this before touching ioremap area */ + vmi_init(); + early_cpu_init(); early_ioremap_init(); @@ -880,13 +883,8 @@ void __init setup_arch(char **cmdline_p) check_efer(); #endif -#if defined(CONFIG_VMI) && defined(CONFIG_X86_32) - /* - * Must be before kernel pagetables are setup - * or fixmap area is touched. - */ - vmi_init(); -#endif + /* Must be before kernel pagetables are setup */ + vmi_activate(); /* after early param, so could get panic from serial */ reserve_early_setup_data(); and according to http://lkml.org/lkml/2008/12/10/388 http://lkml.org/lkml/2008/12/10/456 Zachary should split reserve_top_address() to two functions... before sending that patch to Linus YH