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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 08286C4361B for ; Tue, 15 Dec 2020 10:34:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7DE9206D5 for ; Tue, 15 Dec 2020 10:34:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728421AbgLOKe1 (ORCPT ); Tue, 15 Dec 2020 05:34:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728182AbgLOKeB (ORCPT ); Tue, 15 Dec 2020 05:34:01 -0500 Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B16F3C06179C for ; Tue, 15 Dec 2020 02:33:20 -0800 (PST) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4CwF2z5VRBz9s1l; Tue, 15 Dec 2020 21:33:15 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1608028397; bh=zMpdbTxIQR/bmtXKG54pVnC9KS5pqvpRuMJ/yyVLuug=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=XW66GSBfMlawbQ3SV26jfdKDUXUwCeos7whJAq2/MRxPH7+MmPNmUFRzM5p6ArrcQ Z5fHqVdChMVYv26v6B3lK/7yNHPHUyDuVPzq/h4c9+Nhm2wz8YK0lsZL+YiO2suWVi HwrJcroUFSCVTeceZdwbZv9hisLXqFdRIE9M8BV3MQ2+d1G7nVonFriOLtVnmhn289 mvQvSjlM+73XOM9Je3AOmylZnBkgiuUmLfkP0nS8w7rLiUtZBEaigIWBw++jRyHh84 PRveX7gUqiXOoNiVHJUAp/rKSQn1bbgN7QntdgHcqOy30OFqxmvsL8Bc9ICxGXxs3g /LHydTNn3GWKQ== From: Michael Ellerman To: Nicholas Piggin , Geert Uytterhoeven Cc: "Aneesh Kumar K.V" , Anton Vorontsov , Peter Zijlstra , Linux Kernel Mailing List , linuxppc-dev , Thomas Gleixner Subject: Re: [PATCH 2/2] powerpc/64s: Trim offlined CPUs from mm_cpumasks In-Reply-To: <1607943765.29hccd2b8p.astroid@bobo.none> References: <20201120025757.325930-1-npiggin@gmail.com> <20201120025757.325930-3-npiggin@gmail.com> <1607919238.kj439g85v5.astroid@bobo.none> <87h7oozn06.fsf@mpe.ellerman.id.au> <1607943765.29hccd2b8p.astroid@bobo.none> Date: Tue, 15 Dec 2020 21:33:15 +1100 Message-ID: <875z53z7dg.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nicholas Piggin writes: > Excerpts from Michael Ellerman's message of December 14, 2020 8:43 pm: >> Nicholas Piggin writes: >>> Excerpts from Geert Uytterhoeven's message of December 10, 2020 7:06 pm: >>>> Hi Nicholas, >>>> >>>> On Fri, Nov 20, 2020 at 4:01 AM Nicholas Piggin wrote: >>>>> >>>>> When offlining a CPU, powerpc/64s does not flush TLBs, rather it just >>>>> leaves the CPU set in mm_cpumasks, so it continues to receive TLBIEs >>>>> to manage its TLBs. >>>>> >>>>> However the exit_flush_lazy_tlbs() function expects that after >>>>> returning, all CPUs (except self) have flushed TLBs for that mm, in >>>>> which case TLBIEL can be used for this flush. This breaks for offline >>>>> CPUs because they don't get the IPI to flush their TLB. This can lead >>>>> to stale translations. >>>>> >>>>> Fix this by clearing the CPU from mm_cpumasks, then flushing all TLBs >>>>> before going offline. >>>>> >>>>> These offlined CPU bits stuck in the cpumask also prevents the cpumask >>>>> from being trimmed back to local mode, which means continual broadcast >>>>> IPIs or TLBIEs are needed for TLB flushing. This patch prevents that >>>>> situation too. >>>>> >>>>> Signed-off-by: Nicholas Piggin >>>> >>>> Thanks for your patch! >>>> >>>>> --- a/arch/powerpc/platforms/powermac/smp.c >>>>> +++ b/arch/powerpc/platforms/powermac/smp.c >>>>> @@ -911,6 +911,8 @@ static int smp_core99_cpu_disable(void) >>>>> >>>>> mpic_cpu_set_priority(0xf); >>>>> >>>>> + cleanup_cpu_mmu_context(); >>>>> + >>>> >>>> I guess this change broke pmac32_defconfig+SMP in v5.10-rc7? >>>> >>>> arch/powerpc/platforms/powermac/smp.c: error: implicit >>>> declaration of function 'cleanup_cpu_mmu_context' >>>> [-Werror=implicit-function-declaration]: => 914:2 >>>> >>>> http://kisskb.ellerman.id.au/kisskb/buildresult/14423174/ >>> >>> Hey, yeah it does thanks for catching it. This patch fixes it for me >>> >>> --- >>> From a9b5ec92ffac975e81c6d7db6ff2b1486b2723f7 Mon Sep 17 00:00:00 2001 >>> From: Nicholas Piggin >>> Date: Mon, 14 Dec 2020 13:52:39 +1000 >>> Subject: [PATCH] powerpc/32s: Fix cleanup_cpu_mmu_context() compile bug >>> >>> 32s has no tlbiel_all() defined, so just disable the cleanup with a >>> comment. >> >> Or what about just: > > That works, I kind of wanted it in there explicit that we don't > clean up on 32s. I don't mind if you prefer this though. OK. I'll merge my version because I can do that without needing to merge master in order to get the broken commit into my tree. cheers