From patchwork Mon May 24 10:45:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 12275909 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 685CAC04FF3 for ; Mon, 24 May 2021 10:47:02 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 0C1D86109F for ; Mon, 24 May 2021 10:47:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C1D86109F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44568 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ll86v-0007pd-5V for qemu-devel@archiver.kernel.org; Mon, 24 May 2021 06:47:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48420) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ll85U-00055k-73 for qemu-devel@nongnu.org; Mon, 24 May 2021 06:45:32 -0400 Received: from foss.arm.com ([217.140.110.172]:33438) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ll85R-0005E2-3A for qemu-devel@nongnu.org; Mon, 24 May 2021 06:45:31 -0400 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 599361396; Mon, 24 May 2021 03:45:28 -0700 (PDT) Received: from e112269-lin.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9E4933F719; Mon, 24 May 2021 03:45:25 -0700 (PDT) From: Steven Price To: Catalin Marinas , Marc Zyngier , Will Deacon Subject: [PATCH v13 2/8] arm64: Handle MTE tags zeroing in __alloc_zeroed_user_highpage() Date: Mon, 24 May 2021 11:45:07 +0100 Message-Id: <20210524104513.13258-3-steven.price@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210524104513.13258-1-steven.price@arm.com> References: <20210524104513.13258-1-steven.price@arm.com> MIME-Version: 1.0 Received-SPF: pass client-ip=217.140.110.172; envelope-from=steven.price@arm.com; helo=foss.arm.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Maydell , "Dr. David Alan Gilbert" , Andrew Jones , Haibo Xu , Suzuki K Poulose , qemu-devel@nongnu.org, Dave Martin , Juan Quintela , Richard Henderson , linux-kernel@vger.kernel.org, Steven Price , James Morse , Julien Thierry , Thomas Gleixner , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Catalin Marinas Currently, on an anonymous page fault, the kernel allocates a zeroed page and maps it in user space. If the mapping is tagged (PROT_MTE), set_pte_at() additionally clears the tags under a spinlock to avoid a race on the page->flags. In order to optimise the lock, clear the page tags on allocation in __alloc_zeroed_user_highpage() if the vma flags have VM_MTE set. Signed-off-by: Catalin Marinas Signed-off-by: Steven Price --- arch/arm64/include/asm/page.h | 6 ++++-- arch/arm64/mm/fault.c | 21 +++++++++++++++++++++ 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h index 012cffc574e8..97853570d0f1 100644 --- a/arch/arm64/include/asm/page.h +++ b/arch/arm64/include/asm/page.h @@ -13,6 +13,7 @@ #ifndef __ASSEMBLY__ #include /* for READ_IMPLIES_EXEC */ +#include #include struct page; @@ -28,8 +29,9 @@ void copy_user_highpage(struct page *to, struct page *from, void copy_highpage(struct page *to, struct page *from); #define __HAVE_ARCH_COPY_HIGHPAGE -#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \ - alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr) +struct page *__alloc_zeroed_user_highpage(gfp_t movableflags, + struct vm_area_struct *vma, + unsigned long vaddr); #define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE #define clear_user_page(page, vaddr, pg) clear_page(page) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 871c82ab0a30..5a03428e97f3 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -921,3 +921,24 @@ void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, debug_exception_exit(regs); } NOKPROBE_SYMBOL(do_debug_exception); + +/* + * Used during anonymous page fault handling. + */ +struct page *__alloc_zeroed_user_highpage(gfp_t movableflags, + struct vm_area_struct *vma, + unsigned long vaddr) +{ + struct page *page; + bool tagged = system_supports_mte() && (vma->vm_flags & VM_MTE); + + page = alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, + vaddr); + if (tagged && page) { + mte_clear_page_tags(page_address(page)); + page_kasan_tag_reset(page); + set_bit(PG_mte_tagged, &page->flags); + } + + return page; +}