From patchwork Wed Feb 26 18:05:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 11406943 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 8916C930 for ; Wed, 26 Feb 2020 18:08:07 +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 5B09C24650 for ; Wed, 26 Feb 2020 18:08:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="TwnP0KCO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B09C24650 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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: 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: List-Owner; bh=LsBaleCQ1uL/6Iy7Q84GbizHGRSDnWDHbDZxowlPYJQ=; b=TwnP0KCOYxbNag wi4BVD6gbeR/N2tY7q97vVf91FRNVdKW+NaQoYqjGjTzoYmPGgca2eC5Jx92hGJEtvRh3RQwYiR5/ dIV8l2ibXZUA5lajILofna0fFJdao3pGRzDwphOqG/pqNDkR646jjd5dj/IKlLjMvkQZ+CZmoOFA8 gdwzFriVXuZ244EabyrGZsrESBPXLLT7fZ477NJPfhGG9AV9Ii/JEiouz4HQ+EEpzS00x4ijob0LW 59X5ABtX6NZfa8VaniU3bOkPrsFjW3fIayNPUGljag/4EKHQgDcOrgrZMexyKE6muWpZ9ZFpadD76 9xcP+DKbe21lwtYb4Ljg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j716M-0000sD-4t; Wed, 26 Feb 2020 18:08:06 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j714D-0007TS-Jm for linux-arm-kernel@lists.infradead.org; Wed, 26 Feb 2020 18:05:55 +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 7B84331B; Wed, 26 Feb 2020 10:05:49 -0800 (PST) Received: from arrakis.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0DE473F881; Wed, 26 Feb 2020 10:05:47 -0800 (PST) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 08/19] arm64: Tags-aware memcmp_pages() implementation Date: Wed, 26 Feb 2020 18:05:15 +0000 Message-Id: <20200226180526.3272848-9-catalin.marinas@arm.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200226180526.3272848-1-catalin.marinas@arm.com> References: <20200226180526.3272848-1-catalin.marinas@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200226_100553_757705_16F86D1A X-CRM114-Status: GOOD ( 14.03 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 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: linux-arch@vger.kernel.org, Richard Earnshaw , Szabolcs Nagy , Andrey Konovalov , Kevin Brodsky , Peter Collingbourne , linux-mm@kvack.org, Vincenzo Frascino , Will Deacon Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org When the Memory Tagging Extension is enabled, two pages are identical only if both their data and tags are identical. Make the generic memcmp_pages() a __weak function and add an arm64-specific implementation which takes care of the tags comparison. Co-developed-by: Vincenzo Frascino Signed-off-by: Vincenzo Frascino Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/mte.h | 11 +++++++++ arch/arm64/lib/Makefile | 2 ++ arch/arm64/lib/mte.S | 46 ++++++++++++++++++++++++++++++++++++ arch/arm64/mm/Makefile | 1 + arch/arm64/mm/cmppages.c | 26 ++++++++++++++++++++ mm/util.c | 2 +- 6 files changed, 87 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/mte.h create mode 100644 arch/arm64/lib/mte.S create mode 100644 arch/arm64/mm/cmppages.c diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h new file mode 100644 index 000000000000..64e814273659 --- /dev/null +++ b/arch/arm64/include/asm/mte.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MTE_H +#define __ASM_MTE_H + +#ifndef __ASSEMBLY__ + +/* Memory Tagging API */ +int mte_memcmp_pages(const void *page1_addr, const void *page2_addr); + +#endif /* __ASSEMBLY__ */ +#endif /* __ASM_MTE_H */ diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index 2fc253466dbf..d31e1169d9b8 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -16,3 +16,5 @@ lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o obj-$(CONFIG_CRC32) += crc32.o obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o + +obj-$(CONFIG_ARM64_MTE) += mte.o diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S new file mode 100644 index 000000000000..d41955ab4134 --- /dev/null +++ b/arch/arm64/lib/mte.S @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2019 ARM Ltd. + */ +#include + +#include + +/* + * Compare tags of two pages + * x0 - page1 address + * x1 - page2 address + * Returns: + * w0 - negative, zero or positive value if the tag in the first page is + * less than, equal to or greater than the tag in the second page + */ +ENTRY(mte_memcmp_pages) + multitag_transfer_size x7, x5 +1: + ldgm x2, [x0] + ldgm x3, [x1] + + eor x4, x2, x3 + cbnz x4, 2f + + add x0, x0, x7 + add x1, x1, x7 + + tst x0, #(PAGE_SIZE - 1) + b.ne 1b + + mov w0, #0 + ret +2: + rbit x4, x4 + clz x4, x4 // count the least significant equal bits + and x4, x4, #~3 // round down to a multiple of 4 (bits per tag) + + lsr x2, x2, x4 // remove equal tags + lsr x3, x3, x4 + + lsl w2, w2, #28 // compare the differing tags + sub w0, w2, w3, lsl #28 + + ret +ENDPROC(mte_memcmp_pages) diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index d91030f0ffee..e93d696295d0 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -8,6 +8,7 @@ obj-$(CONFIG_PTDUMP_CORE) += dump.o obj-$(CONFIG_PTDUMP_DEBUGFS) += ptdump_debugfs.o obj-$(CONFIG_NUMA) += numa.o obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o +obj-$(CONFIG_ARM64_MTE) += cmppages.o KASAN_SANITIZE_physaddr.o += n obj-$(CONFIG_KASAN) += kasan_init.o diff --git a/arch/arm64/mm/cmppages.c b/arch/arm64/mm/cmppages.c new file mode 100644 index 000000000000..943c1877e014 --- /dev/null +++ b/arch/arm64/mm/cmppages.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2019 ARM Ltd. + */ + +#include +#include + +#include +#include + +int memcmp_pages(struct page *page1, struct page *page2) +{ + char *addr1, *addr2; + int ret; + + addr1 = page_address(page1); + addr2 = page_address(page2); + + ret = memcmp(addr1, addr2, PAGE_SIZE); + /* if page content identical, check the tags */ + if (ret == 0 && system_supports_mte()) + ret = mte_memcmp_pages(addr1, addr2); + + return ret; +} diff --git a/mm/util.c b/mm/util.c index 988d11e6c17c..662fb3da6d01 100644 --- a/mm/util.c +++ b/mm/util.c @@ -899,7 +899,7 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) return res; } -int memcmp_pages(struct page *page1, struct page *page2) +int __weak memcmp_pages(struct page *page1, struct page *page2) { char *addr1, *addr2; int ret;