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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 8C18DC433DF for ; Wed, 12 Aug 2020 07:46:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 16FE5205CB for ; Wed, 12 Aug 2020 07:46:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 16FE5205CB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4E6686B00C1; Wed, 12 Aug 2020 03:46:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 497876B00C3; Wed, 12 Aug 2020 03:46:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 385BE6B00C4; Wed, 12 Aug 2020 03:46:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0022.hostedemail.com [216.40.44.22]) by kanga.kvack.org (Postfix) with ESMTP id 1ED0E6B00C1 for ; Wed, 12 Aug 2020 03:46:54 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C40B6180AD807 for ; Wed, 12 Aug 2020 07:46:53 +0000 (UTC) X-FDA: 77141135106.25.brick52_53092e926fe9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 8AC2F1804E3A8 for ; Wed, 12 Aug 2020 07:46:53 +0000 (UTC) X-HE-Tag: brick52_53092e926fe9 X-Filterd-Recvd-Size: 3260 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Wed, 12 Aug 2020 07:46:52 +0000 (UTC) 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 F08DAD6E; Wed, 12 Aug 2020 00:46:51 -0700 (PDT) Received: from [10.163.66.87] (unknown [10.163.66.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 280943F22E; Wed, 12 Aug 2020 00:46:49 -0700 (PDT) From: Anshuman Khandual Subject: Re: [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear To: "Aneesh Kumar K.V" , linux-mm@kvack.org, akpm@linux-foundation.org Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org References: <20200812063358.369514-1-aneesh.kumar@linux.ibm.com> Message-ID: <8b951ede-d779-d18f-b2b8-d09f94af6822@arm.com> Date: Wed, 12 Aug 2020 13:16:21 +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: <20200812063358.369514-1-aneesh.kumar@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 8AC2F1804E3A8 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 08/12/2020 12:03 PM, Aneesh Kumar K.V wrote: > With the hash page table, the kernel should not use pmd_clear for clearing > huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage. > > Signed-off-by: Aneesh Kumar K.V This particular change is very much powerpc specific. Hence please drop it from the series which otherwise changes the page table test. Also, this series which is not a RFC, still lacks a proper cover letter with diff stats, tree/tag on which this applies, summary about the proposal etc. All those information will be helpful in reviewing this series better. For now, assuming that this applies cleanly on current master branch. But again, please do include a cover letter in the next version. > --- > arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index 6de56c3b33c4..079211968987 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte) > > static inline void pmd_clear(pmd_t *pmdp) > { > + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { > + /* > + * Don't use this if we can possibly have a hash page table > + * entry mapping this. > + */ > + WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); > + } > *pmdp = __pmd(0); > } > > @@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd) > > static inline void pud_clear(pud_t *pudp) > { > + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { > + /* > + * Don't use this if we can possibly have a hash page table > + * entry mapping this. > + */ > + WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); > + } > *pudp = __pud(0); > } > >