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=-10.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 93AE3C433E0 for ; Fri, 22 Jan 2021 11:23:36 +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 505F822DBF for ; Fri, 22 Jan 2021 11:23:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 505F822DBF 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:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=upIlIpR2tRuCgPFsrU7KMFTt9Ew1Ne31IitJUPYUbnk=; b=on+ZYqPeo/RzvFajPzeWhxWEN qzWINmb/zHqWPHy0kCPzq9MNZwgeQKwqhcTOpUqsaAL5FD2Aa0jQPFUoSsBFkI2EYpq69hz4OHoKm QbM27nB1aUNXTs+dsDO1FAXn8jypTFGWPfLlX9/NQgncp1dogmEQ+fC3MmMQHcYyvbL4KG6P8jbfD xiMOA8ImYK/ZQRLRpGO6uN9psffI4IK4z87XtymQCSTuURuDysmPS5c1wILkNhAl1rY8b5A8docsp 9ZqpdZDL8W/1Wngk6GHKdjDfRo9rrTa114bYehXe92jigFkHswORfVvX48oS5oVq0NeO/n/zsyrLl nZ2aMRE4A==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2uW2-0005Hl-TB; Fri, 22 Jan 2021 11:22:10 +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 1l2uVz-0005HB-Ih for linux-arm-kernel@lists.infradead.org; Fri, 22 Jan 2021 11:22:08 +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 15C6B139F; Fri, 22 Jan 2021 03:22:00 -0800 (PST) Received: from [10.37.8.28] (unknown [10.37.8.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2479F3F719; Fri, 22 Jan 2021 03:21:58 -0800 (PST) Subject: Re: [PATCH v5 2/6] kasan: Add KASAN mode kernel parameter To: Andrey Konovalov References: <20210121163943.9889-1-vincenzo.frascino@arm.com> <20210121163943.9889-3-vincenzo.frascino@arm.com> From: Vincenzo Frascino Message-ID: <770c1426-3e62-e320-9928-37f6ac580c79@arm.com> Date: Fri, 22 Jan 2021 11:25:49 +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: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210122_062207_730839_B0D50E5A X-CRM114-Status: GOOD ( 22.39 ) 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 , LKML , kasan-dev , Alexander Potapenko , Linux ARM , 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 1/21/21 5:34 PM, Andrey Konovalov wrote: >> +- ``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. > Synchronous mode: a bad access is detected immediately when a tag > check fault occurs. > > (No need for `` here, "synchronous mode" is not an inline snippet.) > Ok will do in v5. >> + ``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. > Asynchronous mode: a bad access detection is delayed. When a tag check > fault occurs, the information is stored in hardware (in the TFSR_EL1 > register for arm64). The kernel periodically checks the hardware and > only reports tag faults during these checks. > Will do in v5. >> + >> - ``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, > For other modes I explicitly added a _DEFAULT option first. It makes > sense to do this here as well for consistency. > Will do in v5. >> +}; >> + >> 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(); >> + > Let's add a comment: > > /* Enable async mode only when explicitly requested through the command line. */ > Will do in v5. -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel