From patchwork Thu Jan 21 16:39:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincenzo Frascino X-Patchwork-Id: 12037021 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=-16.9 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,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 21191C433E0 for ; Thu, 21 Jan 2021 16:41:49 +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 75A5323A22 for ; Thu, 21 Jan 2021 16:41:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75A5323A22 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.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=ov4W15iY/B4bPFDwvrzMw5QX3H6BNKhk5F9vaV0fU/k=; b=n9EVVywWSOyJ4jOV791bARkQ4 FzSanq4CeotSULoDqZvaNhZxN1fUCLk4JWHPUjwslfvGsYgdo8eiymBCDkSMx2n1NxONZPhPbTUdA PI0PVe73ZlnHBP9GbBYjUTW3y0p3ZyhTWYUM6eLqBxf9QFA3z3RbdYKJvbGGHKInTH73tjrWaHF7u tuAA1QvBPsZmt1a5+P/I9/lhnRPbw5hibWO9YHCa5aN3Q3lZ/vSIJfNoalUMMoo3cAA2jI3/C1RNg y3epViQZqOJNaApEVrfFUGJxQWJwLUEHQbzmAEG3xILCOjcz6CNlEa6ziSdBsJC1oXlQoBtfcp3WV 5VmNeXJFQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2d0C-00035D-7F; Thu, 21 Jan 2021 16:40:08 +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 1l2d01-00031X-5K for linux-arm-kernel@lists.infradead.org; Thu, 21 Jan 2021 16:39:59 +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 8D9B714FF; Thu, 21 Jan 2021 08:39:56 -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 E24C73F68F; Thu, 21 Jan 2021 08:39:54 -0800 (PST) From: Vincenzo Frascino To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH v5 2/6] kasan: Add KASAN mode kernel parameter Date: Thu, 21 Jan 2021 16:39:39 +0000 Message-Id: <20210121163943.9889-3-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210121_113957_327387_8D076B86 X-CRM114-Status: GOOD ( 21.53 ) 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: Marco Elver , Catalin Marinas , Branislav Rankov , Alexander Potapenko , Evgenii Stepanov , Andrey Konovalov , Andrey Ryabinin , Vincenzo Frascino , Will Deacon , Dmitry Vyukov Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Architectures supported by KASAN_HW_TAGS can provide a sync or async mode of execution. On an MTE enabled arm64 hw for example this can be identified with the 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. KASAN requires a specific kernel command line parameter to make use of this hw features. Add KASAN HW execution mode kernel command line parameter. Note: This patch adds the kasan.mode kernel parameter and the sync/async kernel command line options to enable the described features. Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Signed-off-by: Vincenzo Frascino --- Documentation/dev-tools/kasan.rst | 7 +++++++ lib/test_kasan.c | 2 +- mm/kasan/hw_tags.c | 27 ++++++++++++++++++++++++++- mm/kasan/kasan.h | 6 ++++-- 4 files changed, 38 insertions(+), 4 deletions(-) diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index e022b7506e37..7e4a6e0c9f57 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -161,6 +161,13 @@ particular KASAN features. - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). +- ``kasan.mode=sync`` or ``=async`` controls whether KASAN is configured in + synchronous or asynchronous mode of execution (default: ``sync``). + ``synchronous mode``: an exception is triggered if a tag check fault occurs. + ``asynchronous mode``: if a tag check fault occurs, the information is stored + asynchronously in hardware (e.g. in the TFSR_EL1 register for arm64). The kernel + checks the hardware location and reports an error if the fault is detected. + - ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack traces collection (default: ``on`` for ``CONFIG_DEBUG_KERNEL=y``, otherwise ``off``). diff --git a/lib/test_kasan.c b/lib/test_kasan.c index d16ec9e66806..7285dcf9fcc1 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -97,7 +97,7 @@ static void kasan_test_exit(struct kunit *test) READ_ONCE(fail_data.report_found)); \ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \ if (READ_ONCE(fail_data.report_found)) \ - hw_enable_tagging(); \ + hw_enable_tagging_sync(); \ migrate_enable(); \ } \ } while (0) diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index e529428e7a11..224a2187839c 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -25,6 +25,11 @@ enum kasan_arg { KASAN_ARG_ON, }; +enum kasan_arg_mode { + KASAN_ARG_MODE_SYNC, + KASAN_ARG_MODE_ASYNC, +}; + enum kasan_arg_stacktrace { KASAN_ARG_STACKTRACE_DEFAULT, KASAN_ARG_STACKTRACE_OFF, @@ -38,6 +43,7 @@ enum kasan_arg_fault { }; static enum kasan_arg kasan_arg __ro_after_init; +static enum kasan_arg_mode kasan_arg_mode __ro_after_init; static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init; static enum kasan_arg_fault kasan_arg_fault __ro_after_init; @@ -68,6 +74,21 @@ static int __init early_kasan_flag(char *arg) } early_param("kasan", early_kasan_flag); +/* kasan.mode=sync/async */ +static int __init early_kasan_mode(char *arg) +{ + /* If arg is not set the default mode is sync */ + if ((!arg) || !strcmp(arg, "sync")) + kasan_arg_mode = KASAN_ARG_MODE_SYNC; + else if (!strcmp(arg, "async")) + kasan_arg_mode = KASAN_ARG_MODE_ASYNC; + else + return -EINVAL; + + return 0; +} +early_param("kasan.mode", early_kasan_mode); + /* kasan.stacktrace=off/on */ static int __init early_kasan_flag_stacktrace(char *arg) { @@ -115,7 +136,11 @@ void kasan_init_hw_tags_cpu(void) return; hw_init_tags(KASAN_TAG_MAX); - hw_enable_tagging(); + + if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC) + hw_enable_tagging_async(); + else + hw_enable_tagging_sync(); } /* kasan_init_hw_tags() is called once on boot CPU. */ diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 07ef7fc742ad..3923d9744105 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -294,7 +294,8 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #define arch_set_mem_tag_range(addr, size, tag) ((void *)(addr)) #endif -#define hw_enable_tagging() arch_enable_tagging() +#define hw_enable_tagging_sync() arch_enable_tagging_sync() +#define hw_enable_tagging_async() arch_enable_tagging_async() #define hw_init_tags(max_tag) arch_init_tags(max_tag) #define hw_set_tagging_report_once(state) arch_set_tagging_report_once(state) #define hw_get_random_tag() arch_get_random_tag() @@ -303,7 +304,8 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #else /* CONFIG_KASAN_HW_TAGS */ -#define hw_enable_tagging() +#define hw_enable_tagging_sync() +#define hw_enable_tagging_async() #define hw_set_tagging_report_once(state) #endif /* CONFIG_KASAN_HW_TAGS */