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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 0181BC432C0 for ; Tue, 19 Nov 2019 09:47:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2D55214D9 for ; Tue, 19 Nov 2019 09:47:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726620AbfKSJrw (ORCPT ); Tue, 19 Nov 2019 04:47:52 -0500 Received: from foss.arm.com ([217.140.110.172]:49736 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725280AbfKSJrw (ORCPT ); Tue, 19 Nov 2019 04:47:52 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EED2A1FB; Tue, 19 Nov 2019 01:47:51 -0800 (PST) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3D0833F52E; Tue, 19 Nov 2019 01:47:50 -0800 (PST) Date: Tue, 19 Nov 2019 09:47:47 +0000 From: Qais Yousef To: Michael Ellerman Cc: Thomas Gleixner , Greg Kroah-Hartman , Benjamin Herrenschmidt , Paul Mackerras , Enrico Weigelt , Ram Pai , Nicholas Piggin , Thiago Jung Bauermann , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/12] powerpc: Replace cpu_up/down with device_online/offline Message-ID: <20191119094747.4asxwnmyrjy5d5io@e107158-lin.cambridge.arm.com> References: <20191030153837.18107-1-qais.yousef@arm.com> <20191030153837.18107-4-qais.yousef@arm.com> <87h830d5n8.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87h830d5n8.fsf@mpe.ellerman.id.au> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/19/19 12:19, Michael Ellerman wrote: > Qais Yousef writes: > > The core device API performs extra housekeeping bits that are missing > > from directly calling cpu_up/down. > > > > See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and > > serialization during LPM") for an example description of what might go > > wrong. > > > > This also prepares to make cpu_up/down a private interface for anything > > but the cpu subsystem. > > > > Signed-off-by: Qais Yousef > > CC: Benjamin Herrenschmidt > > CC: Paul Mackerras > > CC: Michael Ellerman > > CC: Enrico Weigelt > > CC: Ram Pai > > CC: Nicholas Piggin > > CC: Thiago Jung Bauermann > > CC: Christophe Leroy > > CC: Thomas Gleixner > > CC: linuxppc-dev@lists.ozlabs.org > > CC: linux-kernel@vger.kernel.org > > --- > > arch/powerpc/kernel/machine_kexec_64.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > My initial though is "what about kdump", but that function is not called > during kdump, so there should be no issue with the extra locking leading > to deadlocks in a crash. > > Acked-by: Michael Ellerman Thanks. > > I assume you haven't actually tested it? Only compile tested it I'm afraid. Would appreciate if you can give it a spin. Otherwise I'd be happy to try it out on qemu. Cheers -- Qais Yousef