From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933557AbaIDBDF (ORCPT ); Wed, 3 Sep 2014 21:03:05 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:30518 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933102AbaIDBDD (ORCPT ); Wed, 3 Sep 2014 21:03:03 -0400 Message-ID: <5407B9F5.2090000@huawei.com> Date: Thu, 4 Sep 2014 09:01:41 +0800 From: "long.wanglong" User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: Russell King - ARM Linux CC: , , , , , , Subject: Re: [SMP BUG?] the return value of is_smp() is bug? References: <1409571334-2814-1-git-send-email-long.wanglong@huawei.com> <20140901101952.GF30401@n2100.arm.linux.org.uk> In-Reply-To: <20140901101952.GF30401@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.88.174] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A02020A.5407BA04.014C,ss=1,re=0.000,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2011-05-27 18:58:46 X-Mirapoint-Loop-Id: 0e34727ccfe9845b9ebc6300ba5ca814 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014/9/1 18:19, Russell King - ARM Linux wrote: > Firstly, do not send multiple copies of your message to mailing lists, > certainly not within the three hours that you sent your three copies. > If one of the addresses you sent the message to bounces, then it is > *only* that one recipient who doesn't get your message, everyone else > receives a copy. So, there's now three copies of your message in the > list archives, and people could end up replying to different messages. > > On Mon, Sep 01, 2014 at 07:35:34PM +0800, Wang Long wrote: >> Hi,all >> >> In kernel 3.17-rc2, when i set CONFIG_HAVE_SMP = y and CONFIG_SMP_ON_UP = y >> in .config file. the secondary core can not boot. >> >> when i set CONFIG_HAVE_SMP = y and CONFIG_SMP_ON_UP = n in .config file, >> the secondary core can boot. >> >> But this does not happen in kernel 3.10 lts kernel, Whether the >> CONFIG_SMP_ON_UP is set yes or no ,the secondary core can boot. >> >> Does the meaning of CONFIG_SMP_ON_UP changed or this is a bug in kernel 3.17-rc2 ? > > I think the answer is neither, because when the kernel is run on /real/ > hardware: > > http://www.arm.linux.org.uk/developer/build/result.php?type=boot&idx=2514 > > it boots fine, bringing up all four CPUs. > >> config: set CONFIG_HAVE_SMP = y and CONFIG_SMP_ON_UP = y >> command: # qemu-system-arm -M vexpress-a9 -smp 2 -m 128M -kernel arch/arm/boot/zImage -nographic > > I've no idea how qemu works here, but if the CPU doesn't indicate that > it's a SMP capable CPU, we will disable SMP extensions. > >> The output: >> >> .......... >> is_smp() return false; >> CPU: Testing write buffer coherency: ok >> missing device node for CPU 0 >> CPU0: thread -1, cpu 0, socket 0, mpidr 80000000 >> Setting up static identity map for 0x604643d8 - 0x60464430 >> Brought up 1 CPUs >> SMP: Total of 1 processors activated. >> CPU: All CPU(s) started in SVC mode. >> ........... > > You have decided that you'll edit the kernel messages, removing at least > some of the information that could be relevant to the issue. Please, > only cut kernel messages when you are absolutely certain that they are > not relevant to the problem you're reporting. > > However, I don't think it would help much - I suspect that qemu doesn't > provide emulation of the SCU base address register, and that's what your > problem is. qemu needs to be fixed in that regard. > Hi,Russell King Thank you for your reply. I will not send multiple copies of message to mailing lists. The problem is that qemu doesn't provide emulation of the SCU base address register.