From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751892Ab0HAFWi (ORCPT ); Sun, 1 Aug 2010 01:22:38 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:20125 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918Ab0HAFWg (ORCPT ); Sun, 1 Aug 2010 01:22:36 -0400 Message-ID: <4C55041C.1030008@kernel.org> Date: Sat, 31 Jul 2010 22:20:28 -0700 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.11) Gecko/20100714 SUSE/3.0.6 Thunderbird/3.0.6 MIME-Version: 1.0 To: "Eric W. Biederman" CC: "H. Peter Anvin" , Cyrill Gorcunov , Ingo Molnar , Thomas Gleixner , Pekka Enberg , "linux-kernel@vger.kernel.org" , kexec@lists.infradead.org Subject: Re: [PATCH] x86,setup: add serial_console_port_base in boot_params References: <4C3F8B46.7080809@kernel.org> <20100731083409.GC5859@lenovo> <4C5469AF.2010608@zytor.com> <20100731183211.GB29357@lenovo> <4C548F7D.6000509@zytor.com> <4C54D3AD.8020906@kernel.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: acsmt353.oracle.com [141.146.40.153] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090207.4C550468.0161,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/31/2010 07:42 PM, Eric W. Biederman wrote: > Yinghai Lu writes: > >> On 07/31/2010 02:02 PM, H. Peter Anvin wrote: >>> On 07/31/2010 11:32 AM, Cyrill Gorcunov wrote: >>>>> >>>>> No, this is the internal part of the boot protocol, so it's not an issue. >>>>> >>>> >>>> Peter, I didn't mean any issue here, I meant that bootloaders don't know about >>>> this field yet and they will have to update own sources to pass port value >>>> at proper place of boot params. Or I miss something? >>>> >>> >>> Boot loaders that use the 16-bit entry point are unaffected. >>> >>> Boot loaders which use the 32-bit entry point but properly clears the >>> zero page simply will not have the feature. >>> >>> Boot loaders which use the 32-bit entry point but doesn't clear the zero >>> page are broken. >>> >> can you if this one is right for kexec path? > > I am walking out the door, but this seems like nonsense to me. > > Further I don't see why we would add something to the zero page > when we have a perfectly good way to pass this information via > the kernel command line. strstr and strtoul are trivial little > functions so I don't see why anything would need to parse anything > other than console= or early_printk=. The difference in code size > is negligible. > so you prefer to check command line for console info in arch/x86/boot/compressed/misc.c again? that commandline is analyzed in arch/x86/boot/tty.c already. Yinghai