From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37033C43387 for ; Tue, 18 Dec 2018 17:28:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9ACC2133F for ; Tue, 18 Dec 2018 17:27:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="D8uioB4q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727277AbeLRR17 (ORCPT ); Tue, 18 Dec 2018 12:27:59 -0500 Received: from pandora.armlinux.org.uk ([78.32.30.218]:45054 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726638AbeLRR16 (ORCPT ); Tue, 18 Dec 2018 12:27:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=S6vVp4p5VJRi7FiPm/Wm3kO9MzkbRcP5S+MOMBuvwzE=; b=D8uioB4qAd8/hm5qDgSspv4yX /5/tcNWreTzu/GhWZhFNFcoIoOfRWqsWJRSs16zcg3z27ySCP+hX64PGF6qzAaKGn7pq0ObVUpVM8 Obu8Ae/X2x6ezO1GSf3SQwPrRy810Udt0nMTPSl89T7azts+VMpTV9uzYyGRKkj5mJAjg=; Received: from n2100.armlinux.org.uk ([2002:4e20:1eda:1:214:fdff:fe10:4f86]:48184) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.90_1) (envelope-from ) id 1gZJ9t-0007M7-9g; Tue, 18 Dec 2018 17:27:53 +0000 Received: from linux by n2100.armlinux.org.uk with local (Exim 4.90_1) (envelope-from ) id 1gZJ9q-0002E2-Ih; Tue, 18 Dec 2018 17:27:50 +0000 Date: Tue, 18 Dec 2018 17:27:48 +0000 From: Russell King - ARM Linux To: Patrice CHOTARD Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/1] ARM: STi: Restore secondary CPU's bringup Message-ID: <20181218172748.GQ26090@n2100.armlinux.org.uk> References: <1545144493-11600-1-git-send-email-patrice.chotard@st.com> <20181218155239.GP26090@n2100.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 18, 2018 at 05:05:18PM +0000, Patrice CHOTARD wrote: > Hi Russell > > On 12/18/18 4:52 PM, Russell King - ARM Linux wrote: > > On Tue, Dec 18, 2018 at 03:48:13PM +0100, patrice.chotard@st.com wrote: > >> From: Patrice Chotard > >> > >> Due to pen_release and boot_lock removal, secondary CPU's bringup > >> was broken. Restore CPU's bringup by reworking properly > >> .smp_prepare_cpus and .smp_boot_secondary STi callbacks. > > > > Sorry, maybe I don't understand your commit message, but you seem to be > > saying that removal of the pen_release and boot_lock broke STi's secondary > > CPU bring up? Please clarify, and explain how that happened. > > Correct, CPU1 failed to come online. > > It seems that writing secondary_startup address at cpu-release-addr in > .smp_prepare_cpus callback was too early. > > Doing it in .smp_boot_secondary callback, insures that secondary_data > struct is populated in __cpu_up() (stack, pgdir and swapper_pg_dir fields). Ah, you're saying that it causes the CPU to jump to secondary_startup while the boot CPU is in smp_prepare_cpus()? What triggers the CPU to jump to the address written to cpu_strt_ptr? What you're saying seems to suggest that it's the write to that address, rather than the IPI that's sent in sti_boot_secondary(). If the IPI in sti_boot_secondary() isn't doing anything, it ought to be removed. It'd also be a good idea to document what's going on as comments in the code for future maintanence. > If you are ok, i will pick up your patch [1] and this one to prepare a > STi pull-request. Yes, although I'll have to delay patch 9 as a result. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up