From patchwork Sat Sep 21 13:50:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jia He X-Patchwork-Id: 11155481 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 BF05B15E6 for ; Sat, 21 Sep 2019 13:51:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8BC67217F5 for ; Sat, 21 Sep 2019 13:51:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8BC67217F5 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 B31146B0003; Sat, 21 Sep 2019 09:51:09 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id AE13F6B0006; Sat, 21 Sep 2019 09:51:09 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F7756B0007; Sat, 21 Sep 2019 09:51:09 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0184.hostedemail.com [216.40.44.184]) by kanga.kvack.org (Postfix) with ESMTP id 7E1DE6B0003 for ; Sat, 21 Sep 2019 09:51:09 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 219938243774 for ; Sat, 21 Sep 2019 13:51:09 +0000 (UTC) X-FDA: 75959064258.10.ants05_7e5bca785f118 X-Spam-Summary: 2,0,0,6f0a9674470297f5,d41d8cd98f00b204,justin.he@arm.com,:catalin.marinas@arm.com:will@kernel.org:mark.rutland@arm.com:james.morse@arm.com:maz@kernel.org:willy@infradead.org:kirill.shutemov@linux.intel.com:linux-arm-kernel@lists.infradead.org:linux-kernel@vger.kernel.org::suzuki.poulose@arm.com:punitagrawal@gmail.com:anshuman.khandual@arm.com:avanbrunt@nvidia.com:robin.murphy@arm.com:tglx@linutronix.de:akpm@linux-foundation.org:jglisse@redhat.com:rcampbell@nvidia.com:hejianet@gmail.com:kaly.xin@arm.com:nd@arm.com:justin.he@arm.com,RULES_HIT:41:355:379:541:968:988:989:1260:1261:1345:1437:1534:1541:1711:1730:1747:1777:1792:1801:2393:2559:2562:2693:2901:3138:3139:3140:3141:3142:3352:3865:3866:3867:3868:3870:3871:4605:5007:6117:6119:6261:6737:6742:7903:8634:10004:11026:11473:11658:11914:12043:12048:12291:12296:12297:12438:12679:12895:13069:13311:13357:14096:14384:14394:14581:14721:21080:21451:21627:21795:30051:30054:30070,0,RBL:217.140.110.172:@arm.com:.lbl8.mail shell.ne X-HE-Tag: ants05_7e5bca785f118 X-Filterd-Recvd-Size: 3074 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Sat, 21 Sep 2019 13:51:08 +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 0419A1570; Sat, 21 Sep 2019 06:51:07 -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 C57413F67D; Sat, 21 Sep 2019 06:51:01 -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 Cc: Punit Agrawal , Anshuman Khandual , Alex Van Brunt , Robin Murphy , Thomas Gleixner , Andrew Morton , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Ralph Campbell , hejianet@gmail.com, Kaly Xin , nd@arm.com, Jia He Subject: [PATCH v8 0/3] fix double page fault on arm64 Date: Sat, 21 Sep 2019 21:50:51 +0800 Message-Id: <20190921135054.142360-1-justin.he@arm.com> X-Mailer: git-send-email 2.17.1 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: 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 v8: change cow_user_page's return type (Matthew) v7: s/pte_spinlock/pte_offset_map_lock (Kirill) v6: fix error case of returning with spinlock taken (Catalin) move kmap_atomic to avoid handling kunmap_atomic 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 (Kirill A. Shutemov) add arch_faults_on_old_pte (Matthew, Catalin) v2: remove FAULT_FLAG_WRITE when setting pte access flag (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 | 10 +++++ arch/arm64/include/asm/pgtable.h | 12 ++++++ mm/memory.c | 67 ++++++++++++++++++++++++++--- 3 files changed, 83 insertions(+), 6 deletions(-)