From patchwork Thu Sep 19 16:12:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin He X-Patchwork-Id: 11152855 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D853C1599 for ; Thu, 19 Sep 2019 16:12:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 B6BF221927 for ; Thu, 19 Sep 2019 16:12:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ppTg0aw9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B6BF221927 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=NncFPxPD5wFl/2p6vqR4YYZojmBc7ltYdyreAD4HQPA=; b=ppT g0aw9q/hpYY1GsZIcMh/iOeMfKt3VH5RvqobW9rwrWp8+PFa64pFVC+S7btDtWUdGlaxHn1me2pVn gt8A7B0XHnGmw04kDCqKizHV/+MjX9TS9F89LP+ZZqcXqk5lS1yMBmN07sLu4t8maOx99e8pTiuzP YNyiYRHuEh/hUAYAz26Z5b+r4uEp9OK6M2M4xJRK/jHMAInkD93MIpMPaw9uWpeBK8s7IrtKM6OpV TE1+uu6WpL/mCW5iICjRFmVaVr1g6S7hA/Kaks9Cy+9AXQ0tGwtqqNiJsGFMK0EfYA+Dfb+UoNOZz A8Za5G3EByOBwr2HSIrjKLv5gO/j7aA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAz2e-00077j-1y; Thu, 19 Sep 2019 16:12:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAz2a-000753-UU for linux-arm-kernel@lists.infradead.org; Thu, 19 Sep 2019 16:12:22 +0000 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 7550728; Thu, 19 Sep 2019 09:12:16 -0700 (PDT) Received: from localhost.localdomain (entos-thunderx2-02.shanghai.arm.com [10.169.40.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 16D013F575; Thu, 19 Sep 2019 09:12:11 -0700 (PDT) From: Jia He To: Catalin Marinas , Will Deacon , Mark Rutland , James Morse , Marc Zyngier , Matthew Wilcox , "Kirill A. Shutemov" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Suzuki Poulose Subject: [PATCH v5 0/3] fix double page fault on arm64 Date: Fri, 20 Sep 2019 00:12:01 +0800 Message-Id: <20190919161204.142796-1-justin.he@arm.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190919_091221_031509_E2718034 X-CRM114-Status: GOOD ( 10.11 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ralph Campbell , Jia He , Anshuman Khandual , Alex Van Brunt , Kaly Xin , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Punit Agrawal , hejianet@gmail.com, Andrew Morton , Robin Murphy , Thomas Gleixner MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org When we tested pmdk unit test vmmalloc_fork TEST1 in arm64 guest, there will be a double page fault in __copy_from_user_inatomic of cow_user_page. As told by Catalin: "On arm64 without hardware Access Flag, copying from user will fail because the pte is old and cannot be marked young. So we always end up with zeroed page after fork() + CoW for pfn mappings. we don't always have a hardware-managed access flag on arm64." Changes v5: handle the case correctly when !pte_same fix kbuild test failed v4: introduce cpu_has_hw_af (Suzuki) bail out if !pte_same (Kirill) v3: add vmf->ptl lock/unlock (by Kirill A. Shutemov) add arch_faults_on_old_pte (Matthew, Catalin) v2: remove FAULT_FLAG_WRITE when setting pte access flag (by Catalin) Jia He (3): arm64: cpufeature: introduce helper cpu_has_hw_af() arm64: mm: implement arch_faults_on_old_pte() on arm64 mm: fix double page fault on arm64 if PTE_AF is cleared arch/arm64/include/asm/cpufeature.h | 1 + arch/arm64/include/asm/pgtable.h | 12 ++++++ arch/arm64/kernel/cpufeature.c | 10 +++++ mm/memory.c | 59 ++++++++++++++++++++++++++--- 4 files changed, 77 insertions(+), 5 deletions(-)