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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 234E2C433DB for ; Sat, 16 Jan 2021 17:23:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E871720791 for ; Sat, 16 Jan 2021 17:23:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727264AbhAPRXR (ORCPT ); Sat, 16 Jan 2021 12:23:17 -0500 Received: from foss.arm.com ([217.140.110.172]:54142 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726754AbhAPRXQ (ORCPT ); Sat, 16 Jan 2021 12:23:16 -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 3E1A9106F; Sat, 16 Jan 2021 05:45:29 -0800 (PST) Received: from [10.37.8.30] (unknown [10.37.8.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0D44A3F719; Sat, 16 Jan 2021 05:45:26 -0800 (PST) Subject: Re: [PATCH v3 2/4] arm64: mte: Add asynchronous mode support To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Catalin Marinas , Will Deacon , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Andrey Konovalov References: <20210115120043.50023-1-vincenzo.frascino@arm.com> <20210115120043.50023-3-vincenzo.frascino@arm.com> <20210115151327.GB44111@C02TD0UTHF1T.local> From: Vincenzo Frascino Message-ID: <2fde5816-35a7-1e21-e42c-f6e413f30aec@arm.com> Date: Sat, 16 Jan 2021 13:49:14 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210115151327.GB44111@C02TD0UTHF1T.local> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/15/21 3:13 PM, Mark Rutland wrote: > On Fri, Jan 15, 2021 at 12:00:41PM +0000, Vincenzo Frascino wrote: >> MTE provides an asynchronous mode for detecting tag exceptions. In >> particular instead of triggering a fault the arm64 core updates a >> register which is checked by the kernel after the asynchronous tag >> check fault has occurred. >> >> Add support for MTE asynchronous mode. >> >> The exception handling mechanism will be added with a future patch. >> >> Note: KASAN HW activates async mode via kasan.mode kernel parameter. >> The default mode is set to synchronous. >> The code that verifies the status of TFSR_EL1 will be added with a >> future patch. >> >> Cc: Catalin Marinas >> Cc: Will Deacon >> Signed-off-by: Vincenzo Frascino >> --- >> arch/arm64/kernel/mte.c | 26 ++++++++++++++++++++++++-- >> 1 file changed, 24 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c >> index 53a6d734e29b..df7a1ae26d7c 100644 >> --- a/arch/arm64/kernel/mte.c >> +++ b/arch/arm64/kernel/mte.c >> @@ -153,8 +153,30 @@ void mte_init_tags(u64 max_tag) >> >> void mte_enable_kernel(enum kasan_hw_tags_mode mode) >> { >> - /* Enable MTE Sync Mode for EL1. */ >> - sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + const char *m; >> + >> + /* Preset parameter values based on the mode. */ >> + switch (mode) { >> + case KASAN_HW_TAGS_ASYNC: >> + /* Enable MTE Async Mode for EL1. */ >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_ASYNC); >> + m = "asynchronous"; >> + break; >> + case KASAN_HW_TAGS_SYNC: >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + m = "synchronous"; >> + break; >> + default: >> + /* >> + * kasan mode should be always set hence we should >> + * not reach this condition. >> + */ >> + WARN_ON_ONCE(1); >> + return; >> + } >> + >> + pr_info_once("MTE: enabled in %s mode at EL1\n", m); >> + >> isb(); >> } > > For clarity, we should have that ISB before the pr_info_once(). > Good point, I will fix it in v4. > As with my comment on patch 1, I think with separate functions this > would be much clearer and simpler: > > static inline void __mte_enable_kernel(const char *mode, unsigned long tcf) > { > sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, tcf); > isb(); > > pr_info_once("MTE: enabled in %s mode at EL1\n", mode); > } > > void mte_enable_kernel_sync(void) > { > __mte_enable_kernel("synchronous", SCTLR_ELx_TCF_SYNC); > } > > void mte_enable_kernel_async(void) > { > __mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC); > } > Ok, seems cleaner like this, will adapt my code accordingly. > Thanks, > Mark. > -- Regards, Vincenzo 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=-15.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 B13B9C433E0 for ; Sat, 16 Jan 2021 13:47:01 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 5D8B523106 for ; 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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l0ltV-00013u-CI; Sat, 16 Jan 2021 13:45:33 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l0ltR-00013L-Sq for linux-arm-kernel@lists.infradead.org; Sat, 16 Jan 2021 13:45:30 +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 3E1A9106F; Sat, 16 Jan 2021 05:45:29 -0800 (PST) Received: from [10.37.8.30] (unknown [10.37.8.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0D44A3F719; Sat, 16 Jan 2021 05:45:26 -0800 (PST) Subject: Re: [PATCH v3 2/4] arm64: mte: Add asynchronous mode support To: Mark Rutland References: <20210115120043.50023-1-vincenzo.frascino@arm.com> <20210115120043.50023-3-vincenzo.frascino@arm.com> <20210115151327.GB44111@C02TD0UTHF1T.local> From: Vincenzo Frascino Message-ID: <2fde5816-35a7-1e21-e42c-f6e413f30aec@arm.com> Date: Sat, 16 Jan 2021 13:49:14 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210115151327.GB44111@C02TD0UTHF1T.local> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210116_084530_048942_B79A974F X-CRM114-Status: GOOD ( 24.25 ) 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: Branislav Rankov , Marco Elver , Catalin Marinas , Evgenii Stepanov , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Andrey Konovalov , Andrey Ryabinin , Will Deacon , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/15/21 3:13 PM, Mark Rutland wrote: > On Fri, Jan 15, 2021 at 12:00:41PM +0000, Vincenzo Frascino wrote: >> MTE provides an asynchronous mode for detecting tag exceptions. In >> particular instead of triggering a fault the arm64 core updates a >> register which is checked by the kernel after the asynchronous tag >> check fault has occurred. >> >> Add support for MTE asynchronous mode. >> >> The exception handling mechanism will be added with a future patch. >> >> Note: KASAN HW activates async mode via kasan.mode kernel parameter. >> The default mode is set to synchronous. >> The code that verifies the status of TFSR_EL1 will be added with a >> future patch. >> >> Cc: Catalin Marinas >> Cc: Will Deacon >> Signed-off-by: Vincenzo Frascino >> --- >> arch/arm64/kernel/mte.c | 26 ++++++++++++++++++++++++-- >> 1 file changed, 24 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c >> index 53a6d734e29b..df7a1ae26d7c 100644 >> --- a/arch/arm64/kernel/mte.c >> +++ b/arch/arm64/kernel/mte.c >> @@ -153,8 +153,30 @@ void mte_init_tags(u64 max_tag) >> >> void mte_enable_kernel(enum kasan_hw_tags_mode mode) >> { >> - /* Enable MTE Sync Mode for EL1. */ >> - sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + const char *m; >> + >> + /* Preset parameter values based on the mode. */ >> + switch (mode) { >> + case KASAN_HW_TAGS_ASYNC: >> + /* Enable MTE Async Mode for EL1. */ >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_ASYNC); >> + m = "asynchronous"; >> + break; >> + case KASAN_HW_TAGS_SYNC: >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + m = "synchronous"; >> + break; >> + default: >> + /* >> + * kasan mode should be always set hence we should >> + * not reach this condition. >> + */ >> + WARN_ON_ONCE(1); >> + return; >> + } >> + >> + pr_info_once("MTE: enabled in %s mode at EL1\n", m); >> + >> isb(); >> } > > For clarity, we should have that ISB before the pr_info_once(). > Good point, I will fix it in v4. > As with my comment on patch 1, I think with separate functions this > would be much clearer and simpler: > > static inline void __mte_enable_kernel(const char *mode, unsigned long tcf) > { > sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, tcf); > isb(); > > pr_info_once("MTE: enabled in %s mode at EL1\n", mode); > } > > void mte_enable_kernel_sync(void) > { > __mte_enable_kernel("synchronous", SCTLR_ELx_TCF_SYNC); > } > > void mte_enable_kernel_async(void) > { > __mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC); > } > Ok, seems cleaner like this, will adapt my code accordingly. > Thanks, > Mark. > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel