From patchwork Tue Apr 21 14:25:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 11501621 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 AC081913 for ; Tue, 21 Apr 2020 14:28:59 +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 6180D206B9 for ; Tue, 21 Apr 2020 14:28:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="iia+HuUY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6180D206B9 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=8PVVqqSMNInwKricd/NE/fb+IkAAFezKO69gQyh+uZ4=; b=iia+HuUYpxLFHG SWMPRY7sphPEyLrtU/OYYTMhK5HMLuOXjLxPraZWeSLvTERVQycOgiAznTKDJwhGci1pYT3i9aAqN 5uzujXltrlVLUrJu+htABmPHZr7iSWE+yO1WHggr5pfcmWYlGB8g+eHYhYcNHWXL7prk5nIAepMte xQqdOgH0rD0VVMkLP8fyd+mQExNBM0Rx2kmMWNNAJS0JWDgZ5RpZBTnUODlVjnIB2ZwlK7iY2q6ju u6E/qttzrd3fMFH8Vm+gyDK2jVuM+J9ngt/cMg+ZGekuM3GSG9T1mNMjqUwGSunK1DV/G4TrrHPql k03CLyUqsGJNd/EyKXuA==; 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 1jQttN-0001uu-Tg; Tue, 21 Apr 2020 14:28:53 +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 1jQtr0-0008FL-NC for linux-arm-kernel@lists.infradead.org; Tue, 21 Apr 2020 14:26:28 +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 E9115C14; Tue, 21 Apr 2020 07:26:25 -0700 (PDT) Received: from localhost.localdomain (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6383D3F68F; Tue, 21 Apr 2020 07:26:24 -0700 (PDT) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 08/23] arm64: Tags-aware memcmp_pages() implementation Date: Tue, 21 Apr 2020 15:25:48 +0100 Message-Id: <20200421142603.3894-9-catalin.marinas@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200421142603.3894-1-catalin.marinas@arm.com> References: <20200421142603.3894-1-catalin.marinas@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200421_072626_867337_149EB779 X-CRM114-Status: GOOD ( 14.68 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 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_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an 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 Cc: Will Deacon --- 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..bd51ea7e2fcb --- /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 + */ +SYM_FUNC_START(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 +SYM_FUNC_END(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;