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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 371D3C48BE6 for ; Wed, 16 Jun 2021 08:04:13 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 A693261159 for ; Wed, 16 Jun 2021 08:04:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A693261159 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=axtens.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4G4d4X0jVQz3cBW for ; Wed, 16 Jun 2021 18:04:12 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=axtens.net header.i=@axtens.net header.a=rsa-sha256 header.s=google header.b=rWR8koka; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=axtens.net (client-ip=2607:f8b0:4864:20::1032; helo=mail-pj1-x1032.google.com; envelope-from=dja@axtens.net; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=axtens.net header.i=@axtens.net header.a=rsa-sha256 header.s=google header.b=rWR8koka; dkim-atps=neutral Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4G4d393ZYSz30CZ for ; Wed, 16 Jun 2021 18:03:01 +1000 (AEST) Received: by mail-pj1-x1032.google.com with SMTP id ei4so1237621pjb.3 for ; Wed, 16 Jun 2021 01:03:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axtens.net; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rH421sL9ZKJVhIfbMwMWVv41eEYVWpLNRPNIYH4GF8E=; b=rWR8kokaYW/1Ws03OSl7FQcv6NX3J8PeEPGquUZjPZp0EiXN1xoAn93b34g1mUVDiV bZsjpSplWHUoBNaL9eEUpaD7KbqnSMVjlFktezoH5yM/kKsrV7iOi23E5xFRZB+3gE1Y GLPYTe2unRYzcu4E1eViAN4Tm54h1Tt9hUB9g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=rH421sL9ZKJVhIfbMwMWVv41eEYVWpLNRPNIYH4GF8E=; b=NOkwzQDrgZ4D4BB1j8+qhEpeGAyJFRSOEU91cUkOT+SlAu4O6ix1c49kIUfY7L14xE m3Pm6o2H7VHs1qD2Mau2Q5/CGA6VzMq1b0J//iLb4H97+/XGA3/FknNxu7gsNSv++tLl KefkQpMctG91sm9noCCCM2ee1AanTru3w7kEjils7WJgeYA6tZK93xC7vzF1P5hE3vP9 CIOmne6+6P5MtlFdR7MCaby5BtkTejPYy76fx1h+iTb4oN5FX97Lj42/wa7Fv5RV2z+j aJRlx/QizaJynZI2gvTiFHat8iprme8u4i+d+rjmQgTm8GXypt513SeFxl4KKSAp3oSs q69g== X-Gm-Message-State: AOAM5328IUvk4UYn1dmi0tU8srnOdym+Rq5lN8+KLD/fUEDl40q0R/en soGPNmnV6Yw8VAfDEsNSDNC3Lg== X-Google-Smtp-Source: ABdhPJwHBPwbeGLF51zGBnN9cTF9GK5Qyaefc/d+iF3iBApps1JGiW3hB5aVTX0B+7hJFgq58tPxIw== X-Received: by 2002:a17:90a:29e2:: with SMTP id h89mr3700284pjd.93.1623830578010; Wed, 16 Jun 2021 01:02:58 -0700 (PDT) Received: from localhost ([203.206.29.204]) by smtp.gmail.com with ESMTPSA id z3sm1398579pgl.77.2021.06.16.01.02.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jun 2021 01:02:57 -0700 (PDT) From: Daniel Axtens To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com, elver@google.com, akpm@linux-foundation.org, andreyknvl@gmail.com Subject: [PATCH v13 2/3] kasan: allow architectures to provide an outline readiness check Date: Wed, 16 Jun 2021 18:02:43 +1000 Message-Id: <20210616080244.51236-3-dja@axtens.net> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210616080244.51236-1-dja@axtens.net> References: <20210616080244.51236-1-dja@axtens.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: aneesh.kumar@linux.ibm.com, "Aneesh Kumar K . V" , linuxppc-dev@lists.ozlabs.org, Daniel Axtens Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Allow architectures to define a kasan_arch_is_ready() hook that bails out of any function that's about to touch the shadow unless the arch says that it is ready for the memory to be accessed. This is fairly uninvasive and should have a negligible performance penalty. This will only work in outline mode, so an arch must specify ARCH_DISABLE_KASAN_INLINE if it requires this. Cc: Balbir Singh Cc: Aneesh Kumar K.V Suggested-by: Christophe Leroy Signed-off-by: Daniel Axtens -- I discuss the justfication for this later in the series. Also, both previous RFCs for ppc64 - by 2 different people - have needed this trick! See: - https://lore.kernel.org/patchwork/patch/592820/ # ppc64 hash series - https://patchwork.ozlabs.org/patch/795211/ # ppc radix series --- mm/kasan/common.c | 4 ++++ mm/kasan/generic.c | 3 +++ mm/kasan/kasan.h | 4 ++++ mm/kasan/shadow.c | 8 ++++++++ 4 files changed, 19 insertions(+) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 10177cc26d06..0ad615f3801d 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -331,6 +331,10 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, u8 tag; void *tagged_object; + /* Bail if the arch isn't ready */ + if (!kasan_arch_is_ready()) + return false; + tag = get_tag(object); tagged_object = object; object = kasan_reset_tag(object); diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 53cbf28859b5..c3f5ba7a294a 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -163,6 +163,9 @@ static __always_inline bool check_region_inline(unsigned long addr, size_t size, bool write, unsigned long ret_ip) { + if (!kasan_arch_is_ready()) + return true; + if (unlikely(size == 0)) return true; diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 8f450bc28045..19323a3d5975 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -449,6 +449,10 @@ static inline void kasan_poison_last_granule(const void *address, size_t size) { #endif /* CONFIG_KASAN_GENERIC */ +#ifndef kasan_arch_is_ready +static inline bool kasan_arch_is_ready(void) { return true; } +#endif + /* * Exported functions for interfaces called from assembly or from generated * code. Declarations here to avoid warning about missing declarations. diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c index 082ee5b6d9a1..3c7f7efe6f68 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -73,6 +73,10 @@ void kasan_poison(const void *addr, size_t size, u8 value, bool init) { void *shadow_start, *shadow_end; + /* Don't touch the shadow memory if arch isn't ready */ + if (!kasan_arch_is_ready()) + return; + /* * Perform shadow offset calculation based on untagged address, as * some of the callers (e.g. kasan_poison_object_data) pass tagged @@ -99,6 +103,10 @@ EXPORT_SYMBOL(kasan_poison); #ifdef CONFIG_KASAN_GENERIC void kasan_poison_last_granule(const void *addr, size_t size) { + /* Don't touch the shadow memory if arch isn't ready */ + if (!kasan_arch_is_ready()) + return; + if (size & KASAN_GRANULE_MASK) { u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size); *shadow = size & KASAN_GRANULE_MASK; -- 2.30.2