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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 5B7CCC3A5A9 for ; Mon, 4 May 2020 12:53:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1D833206D9 for ; Mon, 4 May 2020 12:53:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D833206D9 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 A86598E000D; Mon, 4 May 2020 08:53:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A368D8E0003; Mon, 4 May 2020 08:53:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 94C058E000D; Mon, 4 May 2020 08:53:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0148.hostedemail.com [216.40.44.148]) by kanga.kvack.org (Postfix) with ESMTP id 7B71B8E0003 for ; Mon, 4 May 2020 08:53:31 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 348E4180ACF61 for ; Mon, 4 May 2020 12:53:31 +0000 (UTC) X-FDA: 76779027822.21.quiet21_75fdd6c4d9b39 X-HE-Tag: quiet21_75fdd6c4d9b39 X-Filterd-Recvd-Size: 3228 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 May 2020 12:53:30 +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 B6B5E1FB; Mon, 4 May 2020 05:53:29 -0700 (PDT) Received: from [192.168.1.84] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 85DBD3F71F; Mon, 4 May 2020 05:53:28 -0700 (PDT) Subject: Re: [PATCH 3/4] arm64: mte: Enable swap of tagged pages To: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Andrew Morton , Arnd Bergmann , Hugh Dickins , Vincenzo Frascino , Will Deacon References: <20200422142530.32619-1-steven.price@arm.com> <20200422142530.32619-4-steven.price@arm.com> <20200503152858.GA11959@gaia> From: Steven Price Message-ID: <2ef10bcf-e019-beaf-10fb-b342f96e188c@arm.com> Date: Mon, 4 May 2020 13:53:23 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200503152858.GA11959@gaia> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit 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 03/05/2020 16:29, Catalin Marinas wrote: > On Wed, Apr 22, 2020 at 03:25:29PM +0100, Steven Price wrote: >> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h >> index 39a372bf8afc..a4ad1b75a1a7 100644 >> --- a/arch/arm64/include/asm/pgtable.h >> +++ b/arch/arm64/include/asm/pgtable.h >> @@ -80,6 +80,8 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; >> #define pte_user_exec(pte) (!(pte_val(pte) & PTE_UXN)) >> #define pte_cont(pte) (!!(pte_val(pte) & PTE_CONT)) >> #define pte_devmap(pte) (!!(pte_val(pte) & PTE_DEVMAP)) >> +#define pte_tagged(pte) (!!((pte_val(pte) & PTE_ATTRINDX_MASK) == \ >> + PTE_ATTRINDX(MT_NORMAL_TAGGED))) >> >> #define pte_cont_addr_end(addr, end) \ >> ({ unsigned long __boundary = ((addr) + CONT_PTE_SIZE) & CONT_PTE_MASK; \ >> @@ -268,12 +270,17 @@ static inline void __check_racy_pte_update(struct mm_struct *mm, pte_t *ptep, >> __func__, pte_val(old_pte), pte_val(pte)); >> } >> >> +void mte_sync_tags(pte_t *ptep, pte_t pte); >> + >> static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, >> pte_t *ptep, pte_t pte) >> { >> if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte)) >> __sync_icache_dcache(pte); >> >> + if (system_supports_mte() && pte_tagged(pte)) >> + mte_sync_tags(ptep, pte); > > I think this needs a pte_present() check as well, otherwise pte_tagged() > could match some random swap entry. Good spot - mte_sync_tags() bails out fairly early in this case (which explains why I didn't see any problems). But it's *after* PG_mte_tagged is set which will lead to incorrectly flagging pages. Thanks, Steve