From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753443AbaIAK0p (ORCPT ); Mon, 1 Sep 2014 06:26:45 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:62605 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753154AbaIAK0n (ORCPT ); Mon, 1 Sep 2014 06:26:43 -0400 From: Arnd Bergmann To: "long.wanglong" Cc: linux@arm.linux.org.uk, santosh.shilimkar@ti.com, victor.kamensky@linaro.org, nico@linaro.org, ben.dooks@codethink.co.uk, cov@codeaurora.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [SMP BUG?] the return value of is_smp() is bug? Date: Mon, 01 Sep 2014 12:26 +0200 Message-ID: <25226905.0IHWyHSRxb@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <540443DA.7030502@huawei.com> References: <1409550563-92081-1-git-send-email-long.wanglong@huawei.com> <540443DA.7030502@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V02:K0:H/CKrFIBZMs/OMGmZbJdVj9+KwDT+mtTX+0IDlsE697 nB4pWPWCB/tO6ndrOdSOQDbpEcxK4un9fxa2lGff847BMTcSNy nJQsLYoK4uswoIhkTetQVj/Vjl3nN6ALViw+j6dkGNo8Kdmato R7R+OyHOmQOqWaA34kHXCwWxgt1Vz6D9RUvYEPQqEwyGQqfP9r ZGzcf4SrBZdFj9zUbI3Fcfix9iYPjyy8k8ys7KtgEWhcgJXd36 JvfQDLWXHe8j/CNBXVjzi9chQ0apcEO9prdb/xBqyjvg7sb44L LCdFCq3kXtXLREn/N/3CDroFSCZ82nipMQ5WMA2UcH8IxWLi2K H3VuZ1dfqWIOoSQvaG/0= X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 01 September 2014 18:00:58 long.wanglong wrote: > On 2014/9/1 13:49, 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 ? > > > > > > hi Arnd > > In above two cases, i also set CONFIG_SMP = y. in addtion, > the CONFIG_SMP_ON_UP depends on CONFIG_SMP. when set > CONFIG_SMP_ON_UP = y, the value of CONFIG_SMP must be y. I see. I'm looking at the code more closely now: > > 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 > > The output: > > > > .......... > > is_smp() return false; This test basically checks whether the __fixup_smp_on_up code was run or not. This has changed in bc41b8724f24 "ARM: 7846/1: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices", in order to support a quirk in the Aegis platform. Can you try reverting that commit? Arnd