From mboxrd@z Thu Jan 1 00:00:00 1970 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,URIBL_BLOCKED,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 CE2D7C43381 for ; Thu, 21 Jan 2021 16:43:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 869F323A23 for ; Thu, 21 Jan 2021 16:43:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388001AbhAUQm5 (ORCPT ); Thu, 21 Jan 2021 11:42:57 -0500 Received: from foss.arm.com ([217.140.110.172]:41156 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387854AbhAUQlp (ORCPT ); Thu, 21 Jan 2021 11:41:45 -0500 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 37E9F1595; Thu, 21 Jan 2021 08:40:02 -0800 (PST) Received: from e119884-lin.cambridge.arm.com (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8C92A3F68F; Thu, 21 Jan 2021 08:40:00 -0800 (PST) From: Vincenzo Frascino To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Cc: Vincenzo Frascino , Catalin Marinas , Will Deacon , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Andrey Konovalov Subject: [PATCH v5 5/6] arm64: mte: Expose execution mode Date: Thu, 21 Jan 2021 16:39:42 +0000 Message-Id: <20210121163943.9889-6-vincenzo.frascino@arm.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121163943.9889-1-vincenzo.frascino@arm.com> References: <20210121163943.9889-1-vincenzo.frascino@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org MTE enabled arm64 HW can be configured in synchronous or asynchronous tagging mode of execution. In synchronous mode, an exception is triggered if a tag check fault occurs. In asynchronous mode, if a tag check fault occurs, the TFSR_EL1 register is updated asynchronously. The kernel checks the corresponding bits periodically. Introduce an API that exposes the mode of execution to the kernel. Note: This API will be used by KASAN KUNIT tests to forbid the execution when async mode is enable. Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Vincenzo Frascino --- arch/arm64/include/asm/memory.h | 1 + arch/arm64/include/asm/mte-kasan.h | 6 ++++++ arch/arm64/kernel/mte.c | 8 ++++++++ 3 files changed, 15 insertions(+) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index df96b9c10b81..1d4eef519fa6 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -233,6 +233,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) #ifdef CONFIG_KASAN_HW_TAGS #define arch_enable_tagging_sync() mte_enable_kernel_sync() #define arch_enable_tagging_async() mte_enable_kernel_async() +#define arch_is_mode_sync() mte_is_mode_sync() #define arch_set_tagging_report_once(state) mte_set_report_once(state) #define arch_init_tags(max_tag) mte_init_tags(max_tag) #define arch_get_random_tag() mte_get_random_tag() diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h index 76b6a5988ce5..c216160e805c 100644 --- a/arch/arm64/include/asm/mte-kasan.h +++ b/arch/arm64/include/asm/mte-kasan.h @@ -31,6 +31,7 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag); void mte_enable_kernel_sync(void); void mte_enable_kernel_async(void); +bool mte_is_mode_sync(void); void mte_init_tags(u64 max_tag); void mte_set_report_once(bool state); @@ -64,6 +65,11 @@ static inline void mte_enable_kernel_sync(void) { } +static inline bool mte_is_mode_sync(void) +{ + return false; +} + static inline void mte_init_tags(u64 max_tag) { } diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index 7763ac1f2917..1cc3fc173b97 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -26,6 +26,7 @@ u64 gcr_kernel_excl __ro_after_init; static bool report_fault_once = true; +static bool __mte_mode_sync = true; static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap) { @@ -169,9 +170,16 @@ void mte_enable_kernel_sync(void) void mte_enable_kernel_async(void) { + __mte_mode_sync = false; + __mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC); } +bool mte_is_mode_sync(void) +{ + return __mte_mode_sync; +} + void mte_set_report_once(bool state) { WRITE_ONCE(report_fault_once, state); -- 2.30.0