From patchwork Thu Jun 17 09:30:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Axtens X-Patchwork-Id: 12327105 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,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 0797BC48BE5 for ; Thu, 17 Jun 2021 09:30:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9F0CE610CA for ; Thu, 17 Jun 2021 09:30:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F0CE610CA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=axtens.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 43D9F6B0071; Thu, 17 Jun 2021 05:30:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 414376B0072; Thu, 17 Jun 2021 05:30:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2B52F6B0073; Thu, 17 Jun 2021 05:30:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id EFB186B0071 for ; Thu, 17 Jun 2021 05:30:43 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 9573E180AD804 for ; Thu, 17 Jun 2021 09:30:43 +0000 (UTC) X-FDA: 78262695966.16.3133706 Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) by imf23.hostedemail.com (Postfix) with ESMTP id D3251A0001CF for ; Thu, 17 Jun 2021 09:30:33 +0000 (UTC) Received: by mail-pf1-f180.google.com with SMTP id x73so4519983pfc.8 for ; Thu, 17 Jun 2021 02:30:43 -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=1nSYxJY0N3aZr/pdi8HOrkpkeyyKzwB00+Ef/RsvCEU=; b=VxBhETKa1BkglHL6eiGuDKau5qIlvO2SE6buqTTYwaSC4Qq5gYa8/0Iu8HTz88B0+o bv8FuQFbSiqr5YoaoJu0h/DwAkJzkeYN4j9I34Y3qNg1dnVP4NtMb2C4vKeoWXhrcSFi LAMbptK+3YwoGNurib7Mg7XZAtIEpcnkIpe6s= 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=1nSYxJY0N3aZr/pdi8HOrkpkeyyKzwB00+Ef/RsvCEU=; b=tBzzhdwVDtdPJLbMGVhYH+e0H7uGd/geEVYs0AOqzn/FtgD+NrzfoAI/QsK81iC6hX 2kgKSH8Oe/5OYuSuXcG81vMltifCxbdhen7a9X8EqhhccVPCiTLRxLHe6eDMvwpxQqfW ywMC/sst3OxhtFviD0h67zCVJjozvL2s0jV2aST0OD5djTCH0CR/2lNrBswZMbrW5do0 rC2zEQwGOADwaIvpQbxaHZpTR5qSBm7Be7o3AzCyVr1oUWXbP2pAIQsB/r9gZUCS7jx0 aF4Ae2gn2LLK0thpYZKWF/6FaNbGsCv5coMOGraRR+fxmV27TacC2MSyLDyuAwTWvGIi cGHw== X-Gm-Message-State: AOAM530inE7aM2cgG+I0HmwWiRILJJ8gjfT+zJyO1tc3xDDwu1x3gk+C wkFhOQ8vvsVFbFKNNRT5FvW9pw== X-Google-Smtp-Source: ABdhPJyV1oWZvDdmYRFVr5QxoEcMf74PgidkzSk77dFrjXAyQzrlIf5IqVEJJ6SfYAnO1F6jO2BI8A== X-Received: by 2002:a62:380c:0:b029:2f7:4057:c3ed with SMTP id f12-20020a62380c0000b02902f74057c3edmr4363473pfa.21.1623922242435; Thu, 17 Jun 2021 02:30:42 -0700 (PDT) Received: from localhost ([203.206.29.204]) by smtp.gmail.com with ESMTPSA id a23sm4404876pff.43.2021.06.17.02.30.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Jun 2021 02:30:42 -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 Cc: linuxppc-dev@lists.ozlabs.org, christophe.leroy@csgroup.eu, aneesh.kumar@linux.ibm.com, bsingharora@gmail.com, Daniel Axtens Subject: [PATCH v15 1/4] kasan: allow an architecture to disable inline instrumentation Date: Thu, 17 Jun 2021 19:30:29 +1000 Message-Id: <20210617093032.103097-2-dja@axtens.net> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210617093032.103097-1-dja@axtens.net> References: <20210617093032.103097-1-dja@axtens.net> MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D3251A0001CF X-Stat-Signature: 6tze55wzzbrw95w1r7x14hsn5jpfwi7u Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=axtens.net header.s=google header.b=VxBhETKa; dmarc=none; spf=pass (imf23.hostedemail.com: domain of dja@axtens.net designates 209.85.210.180 as permitted sender) smtp.mailfrom=dja@axtens.net X-HE-Tag: 1623922233-924254 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: For annoying architectural reasons, it's very difficult to support inline instrumentation on powerpc64.* Add a Kconfig flag to allow an arch to disable inline. (It's a bit annoying to be 'backwards', but I'm not aware of any way to have an arch force a symbol to be 'n', rather than 'y'.) We also disable stack instrumentation in this case as it does things that are functionally equivalent to inline instrumentation, namely adding code that touches the shadow directly without going through a C helper. * on ppc64 atm, the shadow lives in virtual memory and isn't accessible in real mode. However, before we turn on virtual memory, we parse the device tree to determine which platform and MMU we're running under. That calls generic DT code, which is instrumented. Inline instrumentation in DT would unconditionally attempt to touch the shadow region, which we won't have set up yet, and would crash. We can make outline mode wait for the arch to be ready, but we can't change what the compiler inserts for inline mode. Reviewed-by: Marco Elver Signed-off-by: Daniel Axtens --- lib/Kconfig.kasan | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index cffc2ebbf185..cb5e02d09e11 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -12,6 +12,15 @@ config HAVE_ARCH_KASAN_HW_TAGS config HAVE_ARCH_KASAN_VMALLOC bool +config ARCH_DISABLE_KASAN_INLINE + bool + help + Sometimes an architecture might not be able to support inline + instrumentation but might be able to support outline instrumentation. + This option allows an architecture to prevent inline and stack + instrumentation from being enabled. + + config CC_HAS_KASAN_GENERIC def_bool $(cc-option, -fsanitize=kernel-address) @@ -130,6 +139,7 @@ config KASAN_OUTLINE config KASAN_INLINE bool "Inline instrumentation" + depends on !ARCH_DISABLE_KASAN_INLINE help Compiler directly inserts code checking shadow memory before memory accesses. This is faster than outline (in some workloads @@ -141,6 +151,7 @@ endchoice config KASAN_STACK bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST depends on KASAN_GENERIC || KASAN_SW_TAGS + depends on !ARCH_DISABLE_KASAN_INLINE default y if CC_IS_GCC help The LLVM stack address sanitizer has a know problem that @@ -154,6 +165,9 @@ config KASAN_STACK but clang users can still enable it for builds without CONFIG_COMPILE_TEST. On gcc it is assumed to always be safe to use and enabled by default. + If the architecture disables inline instrumentation, this is + also disabled as it adds inline-style instrumentation that + is run unconditionally. config KASAN_SW_TAGS_IDENTIFY bool "Enable memory corruption identification"