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: 11406907 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 883D314B4 for ; Wed, 26 Feb 2020 18:05:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5F19520732 for ; Wed, 26 Feb 2020 18:05:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F19520732 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 1640F6B0078; Wed, 26 Feb 2020 13:05:51 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 0EFB86B007B; Wed, 26 Feb 2020 13:05:50 -0500 (EST) 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 DBEE46B007D; Wed, 26 Feb 2020 13:05:50 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0149.hostedemail.com [216.40.44.149]) by kanga.kvack.org (Postfix) with ESMTP id C47A96B0078 for ; Wed, 26 Feb 2020 13:05:50 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 9C65B8245571 for ; Wed, 26 Feb 2020 18:05:50 +0000 (UTC) X-FDA: 76533056460.26.rub40_32f53533bbb4e X-Spam-Summary: 2,0,0,0f0c5a3f70513d8b,d41d8cd98f00b204,catalin.marinas@arm.com,,RULES_HIT:41:355:379:541:800:960:968:973:988:989:1260:1261:1311:1314:1345:1359:1431:1437:1515:1535:1544:1605:1711:1730:1747:1777:1792:1801:1981:2194:2199:2393:2538:2559:2562:3138:3139:3140:3141:3142:3865:3866:3867:3868:3870:3871:4321:4605:5007:6117:6119:6261:7875:7903:8634:10004:11026:11473:11657:11658:11914:12043:12291:12296:12297:12438:12555:12683:12986:13894:14096:14181:14394:14721:21080:21230:21451:21627:21990:30003:30054:30067:30070,0,RBL:217.140.110.172:@arm.com:.lbl8.mailshell.net-62.2.0.100 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: rub40_32f53533bbb4e X-Filterd-Recvd-Size: 5935 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Wed, 26 Feb 2020 18:05:50 +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 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 Cc: Will Deacon , Vincenzo Frascino , Szabolcs Nagy , Richard Earnshaw , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , linux-mm@kvack.org, linux-arch@vger.kernel.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-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 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;