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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 E5D40C433E0 for ; Fri, 19 Jun 2020 11:18:05 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9E1452080C for ; Fri, 19 Jun 2020 11:18:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E1452080C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49pGWH5NtRzDqhN for ; Fri, 19 Jun 2020 21:18:03 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 49pGSv0YCRzDrN0 for ; Fri, 19 Jun 2020 21:15:56 +1000 (AEST) 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 2B12CD6E; Fri, 19 Jun 2020 04:15:52 -0700 (PDT) Received: from [10.163.81.119] (unknown [10.163.81.119]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5B7513F6CF; Fri, 19 Jun 2020 04:15:48 -0700 (PDT) Subject: Re: [PATCH] mm/debug_vm_pgtable: Fix build failure with powerpc 8xx To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Will Deacon , Andrew Morton , "Peter Zijlstra (Intel)" References: <6ca8c972e6c920dc4ae0d4affbed9703afa4d010.1592490570.git.christophe.leroy@csgroup.eu> From: Anshuman Khandual Message-ID: <7af42230-2707-d35a-d7ff-6c83b2afdbbb@arm.com> Date: Fri, 19 Jun 2020 16:45:39 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <6ca8c972e6c920dc4ae0d4affbed9703afa4d010.1592490570.git.christophe.leroy@csgroup.eu> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 06/18/2020 08:01 PM, Christophe Leroy wrote: > Fix it by using the recently added ptep_get() helper. > > Fixes: 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses") > Signed-off-by: Christophe Leroy > --- > mm/debug_vm_pgtable.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index e45623016aea..61ab16fb2e36 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -246,13 +246,13 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, > static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep, > unsigned long vaddr) > { > - pte_t pte = READ_ONCE(*ptep); > + pte_t pte = ptep_get(ptep); > > pte = __pte(pte_val(pte) | RANDOM_ORVALUE); > set_pte_at(mm, vaddr, ptep, pte); > barrier(); > pte_clear(mm, vaddr, ptep); > - pte = READ_ONCE(*ptep); > + pte = ptep_get(ptep); > WARN_ON(!pte_none(pte)); > } Tested this on arm64 and x86 platforms after applying the previous series which adds ptep_get() and a follow up patch. https://patchwork.kernel.org/project/linux-mm/list/?series=302949 https://patchwork.kernel.org/patch/11611929/ Build tested on s390 and arc platforms as well. Reviewed-by: Anshuman Khandual