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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 C3D74C47423 for ; Thu, 1 Oct 2020 17:57:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3F2C02226A for ; Thu, 1 Oct 2020 17:57:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Ftzp9vYt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F2C02226A Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A74FC90001F; Thu, 1 Oct 2020 13:57:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A24A6900003; Thu, 1 Oct 2020 13:57:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 93C5790001F; Thu, 1 Oct 2020 13:57:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0230.hostedemail.com [216.40.44.230]) by kanga.kvack.org (Postfix) with ESMTP id 6A23E900003 for ; Thu, 1 Oct 2020 13:57:28 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 014822479 for ; Thu, 1 Oct 2020 17:57:28 +0000 (UTC) X-FDA: 77324113776.14.alley58_27179512719d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin14.hostedemail.com (Postfix) with ESMTP id D28E218229835 for ; Thu, 1 Oct 2020 17:57:27 +0000 (UTC) X-HE-Tag: alley58_27179512719d X-Filterd-Recvd-Size: 9150 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Thu, 1 Oct 2020 17:57:27 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id t10so6848611wrv.1 for ; Thu, 01 Oct 2020 10:57:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=NrXP5K1QAOK1ooEoF09QcxyxzBvczwzY+6+OVR8Sv6k=; b=Ftzp9vYtlhuwTGkJFwqeer6Kks0+qgmyYK49BtNL7KyMB9YkFWpVM6yahd0J1rg15V WXlVOUzDt+6rGijpoHCmHgs8o6/BFrebhcVdjNfx1uy/FuLZDzAJmVth+3Q9q9/NKLcs 2o0VNhJ//vitVKO82CY+yEJqkRSlnkCRxvpi2eTJmR3LPeWY60/vBVbemMiA2I5bspGA co8GVGvsbDSV/Zs7fOXOJFfgqEJShfhZDC4O/BOFu2wdr57c4LXtf+/gfkLcYRDkFEnD sNIwohgX6++pWxRVapKSyiblekRbahtYyEFwkXYLF2HQI8q5a+5h7SKIRsBcPsdb0yzS paMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=NrXP5K1QAOK1ooEoF09QcxyxzBvczwzY+6+OVR8Sv6k=; b=ZTAxLUhNn9tNRX7T+JvDKGHAcXm/LfZZnIAQFeWZ6tt4Xx6Fn8ObfCRzQSzcLzx+Wn XkIq3ELEf0hNIwCPaLW5MJ4M8spoGgOh2jG5O3Gv2540n9hDaaoPRLcCxRc45WHawtEW eZF64N5P9aazT1Fmu+4oK0IoZUVJ+0eFOajpl4V+WD7fKwG0VUMJDF2w5XEAa22uKJH9 Vq/39N0Zqy+yIOx3R2I5mSZ4LK78yP0Ap1SqlQS/dChtenSzkL+XRk5O7bW7hMt0aXsl QuvQsCDKYapJ22LUBdF7kaK3OpXN5iOxl7Yq2Bn9vsfnspH+KEkQGuubHB1crajPcGvB z/ig== X-Gm-Message-State: AOAM530gxzPtdO1Wu5MXDruiRoS6CZFBj313P954YQYimtqcfvxiK3Pc UEND4PBXJdIhEhDZr7my84J7FQ== X-Google-Smtp-Source: ABdhPJwGZNOXk9mj0Pqo41aou7Hqb8qY43tJa83Ff/NYunQpvUmCCWMBZx1ty7TKXBr/EJGK8M1KSA== X-Received: by 2002:adf:dd82:: with SMTP id x2mr10956498wrl.419.1601575045792; Thu, 01 Oct 2020 10:57:25 -0700 (PDT) Received: from elver.google.com ([100.105.32.75]) by smtp.gmail.com with ESMTPSA id j10sm10054494wrn.2.2020.10.01.10.57.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Oct 2020 10:57:25 -0700 (PDT) Date: Thu, 1 Oct 2020 19:57:19 +0200 From: elver@google.com To: Andrey Konovalov Cc: Dmitry Vyukov , Vincenzo Frascino , Catalin Marinas , kasan-dev@googlegroups.com, Andrey Ryabinin , Alexander Potapenko , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 22/39] kasan: introduce CONFIG_KASAN_HW_TAGS Message-ID: <20201001175719.GR4162920@elver.google.com> References: <76937ee6e88d0d1fc98003e503f31fe7b14a6a52.1600987622.git.andreyknvl@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <76937ee6e88d0d1fc98003e503f31fe7b14a6a52.1600987622.git.andreyknvl@google.com> User-Agent: Mutt/1.14.5 (2020-06-23) 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: On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote: > This patch adds a configuration option for a new KASAN mode called > hardware tag-based KASAN. This mode uses the memory tagging approach > like the software tag-based mode, but relies on arm64 Memory Tagging > Extension feature for tag management and access checking. > > Signed-off-by: Andrey Konovalov > Signed-off-by: Vincenzo Frascino Reviewed-by: Marco Elver > --- > Change-Id: I246c2def9fffa6563278db1bddfbe742ca7bdefe > --- > lib/Kconfig.kasan | 59 ++++++++++++++++++++++++++++++++--------------- > 1 file changed, 41 insertions(+), 18 deletions(-) > > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan > index b4cf6c519d71..516d3a24f7d7 100644 > --- a/lib/Kconfig.kasan > +++ b/lib/Kconfig.kasan > @@ -6,7 +6,10 @@ config HAVE_ARCH_KASAN > config HAVE_ARCH_KASAN_SW_TAGS > bool > > -config HAVE_ARCH_KASAN_VMALLOC > +config HAVE_ARCH_KASAN_HW_TAGS > + bool > + > +config HAVE_ARCH_KASAN_VMALLOC > bool > > config CC_HAS_KASAN_GENERIC > @@ -20,11 +23,11 @@ config CC_HAS_WORKING_NOSANITIZE_ADDRESS > > menuconfig KASAN > bool "KASAN: runtime memory debugger" > - depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \ > - (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS) > + depends on (((HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \ > + (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)) && \ > + CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \ > + HAVE_ARCH_KASAN_HW_TAGS > depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB) > - depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS > - select SLUB_DEBUG if SLUB See my comment in the other patch about moving this line again. > select CONSTRUCTORS > select STACKDEPOT > help > @@ -38,17 +41,23 @@ choice > prompt "KASAN mode" > default KASAN_GENERIC > help > - KASAN has two modes: generic KASAN (similar to userspace ASan, > - x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and > - software tag-based KASAN (a version based on software memory > - tagging, arm64 only, similar to userspace HWASan, enabled with > - CONFIG_KASAN_SW_TAGS). > + KASAN has three modes: > + 1. generic KASAN (similar to userspace ASan, > + x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC), > + 2. software tag-based KASAN (arm64 only, based on software > + memory tagging (similar to userspace HWASan), enabled with > + CONFIG_KASAN_SW_TAGS), and > + 3. hardware tag-based KASAN (arm64 only, based on hardware > + memory tagging, enabled with CONFIG_KASAN_HW_TAGS). > + > + All KASAN modes are strictly debugging features. > > - Both generic and tag-based KASAN are strictly debugging features. > + For better error reports enable CONFIG_STACKTRACE. > > config KASAN_GENERIC > bool "Generic mode" > depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC > + select SLUB_DEBUG if SLUB > help > Enables generic KASAN mode. > > @@ -61,20 +70,21 @@ config KASAN_GENERIC > and introduces an overhead of ~x1.5 for the rest of the allocations. > The performance slowdown is ~x3. > > - For better error detection enable CONFIG_STACKTRACE. > - > Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB > (the resulting kernel does not boot). > > config KASAN_SW_TAGS > bool "Software tag-based mode" > depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS > + select SLUB_DEBUG if SLUB > help > Enables software tag-based KASAN mode. > > - This mode requires Top Byte Ignore support by the CPU and therefore > - is only supported for arm64. This mode requires Clang version 7.0.0 > - or later. > + This mode require software memory tagging support in the form of > + HWASan-like compiler instrumentation. > + > + Currently this mode is only implemented for arm64 CPUs and relies on > + Top Byte Ignore. This mode requires Clang version 7.0.0 or later. > > This mode consumes about 1/16th of available memory at kernel start > and introduces an overhead of ~20% for the rest of the allocations. > @@ -82,15 +92,27 @@ config KASAN_SW_TAGS > casting and comparison, as it embeds tags into the top byte of each > pointer. > > - For better error detection enable CONFIG_STACKTRACE. > - > Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB > (the resulting kernel does not boot). > > +config KASAN_HW_TAGS > + bool "Hardware tag-based mode" > + depends on HAVE_ARCH_KASAN_HW_TAGS > + depends on SLUB > + help > + Enables hardware tag-based KASAN mode. > + > + This mode requires hardware memory tagging support, and can be used > + by any architecture that provides it. > + > + Currently this mode is only implemented for arm64 CPUs starting from > + ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore. > + > endchoice > > choice > prompt "Instrumentation type" > + depends on KASAN_GENERIC || KASAN_SW_TAGS > default KASAN_OUTLINE > > config KASAN_OUTLINE > @@ -114,6 +136,7 @@ endchoice > > config KASAN_STACK_ENABLE > bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST > + depends on KASAN_GENERIC || KASAN_SW_TAGS > help > The LLVM stack address sanitizer has a know problem that > causes excessive stack usage in a lot of functions, see > -- > 2.28.0.681.g6f77f65b4e-goog >