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Mon, 14 Jun 2021 18:47:15 -0700 (PDT) Received: from localhost ([203.206.29.204]) by smtp.gmail.com with ESMTPSA id gk21sm13168157pjb.22.2021.06.14.18.47.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Jun 2021 18:47:14 -0700 (PDT) From: Daniel Axtens To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, kasan-dev@googlegroups.com, christophe.leroy@csgroup.eu, aneesh.kumar@linux.ibm.com, bsingharora@gmail.com Cc: elver@google.com, Daniel Axtens Subject: [PATCH v12 1/6] kasan: allow an architecture to disable inline instrumentation Date: Tue, 15 Jun 2021 11:47:00 +1000 Message-Id: <20210615014705.2234866-2-dja@axtens.net> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210615014705.2234866-1-dja@axtens.net> References: <20210615014705.2234866-1-dja@axtens.net> MIME-Version: 1.0 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=axtens.net header.s=google header.b=Pn6LBDzC; spf=pass (imf13.hostedemail.com: domain of dja@axtens.net designates 209.85.215.176 as permitted sender) smtp.mailfrom=dja@axtens.net; dmarc=none X-Stat-Signature: hepr3a6h94cupfcbxnga1ush7eqcz5h1 X-Rspamd-Queue-Id: A4005E000243 X-Rspamd-Server: rspam06 X-HE-Tag: 1623721627-211478 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. 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..935814f332a7 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 +# Sometimes an architecture might not be able to support inline instrumentation +# but might be able to support outline instrumentation. This option allows an +# arch to prevent inline and stack instrumentation from being enabled. +# ppc64 turns on virtual memory late in boot, after calling into generic code +# like the device-tree parser, so it uses this in conjuntion with a hook in +# outline mode to avoid invalid access early in boot. +config ARCH_DISABLE_KASAN_INLINE + bool + 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" From patchwork Tue Jun 15 01:47:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Axtens X-Patchwork-Id: 12320383 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 26C71C2B9F4 for ; Tue, 15 Jun 2021 01:47:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B38646140B for ; Tue, 15 Jun 2021 01:47:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B38646140B 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 5834C6B0070; Mon, 14 Jun 2021 21:47:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 50B6D6B0071; Mon, 14 Jun 2021 21:47:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 387B66B0072; Mon, 14 Jun 2021 21:47:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0032.hostedemail.com [216.40.44.32]) by kanga.kvack.org (Postfix) with ESMTP id 016F66B0070 for ; Mon, 14 Jun 2021 21:47:20 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 9EB27BBC8 for ; Tue, 15 Jun 2021 01:47:20 +0000 (UTC) X-FDA: 78254270640.13.EDDFF27 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) by imf07.hostedemail.com (Postfix) with ESMTP id E119EA0001CF for ; Tue, 15 Jun 2021 01:47:10 +0000 (UTC) Received: by mail-pj1-f42.google.com with SMTP id o88-20020a17090a0a61b029016eeb2adf66so586590pjo.4 for ; Mon, 14 Jun 2021 18:47:19 -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=9yfG43b2K5TzVk5ZU+QSFD/NukUJWMplQuDr+tXNhQQ=; b=Zp8KnLUSatybticlxZJApD0i9G8GXZx7RpoNRl1/7XodZnv+q2U9g29MDo5vvrQxLQ 7Y/gzsANS6ZqQigBUlcKaa7bQlBiMlZ6WyHTlqx9NI+D6nSRIgUkUIPH5IEvWv+o+xOX R+avk3QSGA1U5XWfPL50c0h907VeEKM8o1Qvo= 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=9yfG43b2K5TzVk5ZU+QSFD/NukUJWMplQuDr+tXNhQQ=; b=cdHHj+9pwXEduDg5W6CLJL8XUQmTL35AopapZ2CJAUkJlvPJSGfo7/lx3DxYTbgBH3 F1AVRBT6shFpZhvV/N9zVooJkeb6kGciI7qo0rQk0yLQ+KsF5MNeMMlOdixbge0lbKK3 RpkhYPDSPXeUrMix3/zcq8QML/4MrijA4jc82kJKxI29hocyl3AQQh1Jv9oyfzlGOaV2 StE7LVRPM1kVrwLmtmABuXSzv4YrAos0bpmrONz10D6WPxBV6GLx3kZ2GpRMmlZhkwdY W2K0vLuoEqnjkoLI6T5s03thWJD+c81QqQpbgcKO4WCsfMm/tLRbzPjryd1rmvTyupNE zyHA== X-Gm-Message-State: AOAM530AMOs7rXGTDm/FamgIp/s8iZ9akolKDKn/uGKXDab7qxtmnzVt JaaWSdZNS6QCbGZHDst3m5T2Og== X-Google-Smtp-Source: ABdhPJwayJvIluspopg5KlfYC5uZhjdSK6RLrVbRnbo5dYy82BcNvz2/dLQevVxTLK0wqyDRuuEEFA== X-Received: by 2002:a17:902:d888:b029:11c:1010:f0ea with SMTP id b8-20020a170902d888b029011c1010f0eamr1621088plz.68.1623721639363; Mon, 14 Jun 2021 18:47:19 -0700 (PDT) Received: from localhost ([203.206.29.204]) by smtp.gmail.com with ESMTPSA id n14sm13096115pfa.138.2021.06.14.18.47.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Jun 2021 18:47:18 -0700 (PDT) From: Daniel Axtens To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, kasan-dev@googlegroups.com, christophe.leroy@csgroup.eu, aneesh.kumar@linux.ibm.com, bsingharora@gmail.com Cc: elver@google.com, Daniel Axtens , "Aneesh Kumar K . V" Subject: [PATCH v12 2/6] kasan: allow architectures to provide an outline readiness check Date: Tue, 15 Jun 2021 11:47:01 +1000 Message-Id: <20210615014705.2234866-3-dja@axtens.net> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210615014705.2234866-1-dja@axtens.net> References: <20210615014705.2234866-1-dja@axtens.net> MIME-Version: 1.0 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E119EA0001CF Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=axtens.net header.s=google header.b=Zp8KnLUS; spf=pass (imf07.hostedemail.com: domain of dja@axtens.net designates 209.85.216.42 as permitted sender) smtp.mailfrom=dja@axtens.net; dmarc=none X-Stat-Signature: ywwd6qim9kyye9sst43649efcy6dwp4q X-HE-Tag: 1623721630-137007 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: 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 | 4 ++++ 4 files changed, 15 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..74134b657d7d 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 From patchwork Tue Jun 15 01:47:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Axtens X-Patchwork-Id: 12320385 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 40091C2B9F4 for ; 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dkim=pass header.d=axtens.net header.s=google header.b=YYXooO3C; dmarc=none; spf=pass (imf10.hostedemail.com: domain of dja@axtens.net designates 209.85.215.175 as permitted sender) smtp.mailfrom=dja@axtens.net X-Stat-Signature: q54rb7rwcreshnwsfuia11neij5aqs76 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0A52B40002C1 X-HE-Tag: 1623721635-434240 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: powerpc has a variable number of PTRS_PER_*, set at runtime based on the MMU that the kernel is booted under. This means the PTRS_PER_* are no longer constants, and therefore breaks the build. Define default MAX_PTRS_PER_*s in the same style as MAX_PTRS_PER_P4D. As KASAN is the only user at the moment, just define them in the kasan header, and have them default to PTRS_PER_* unless overridden in arch code. Suggested-by: Christophe Leroy Suggested-by: Balbir Singh Reviewed-by: Christophe Leroy Reviewed-by: Balbir Singh Signed-off-by: Daniel Axtens --- include/linux/kasan.h | 18 +++++++++++++++--- mm/kasan/init.c | 6 +++--- 2 files changed, 18 insertions(+), 6 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 768d7d342757..fd65f477ac92 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -40,10 +40,22 @@ struct kunit_kasan_expectation { #define PTE_HWTABLE_PTRS 0 #endif +#ifndef MAX_PTRS_PER_PTE +#define MAX_PTRS_PER_PTE PTRS_PER_PTE +#endif + +#ifndef MAX_PTRS_PER_PMD +#define MAX_PTRS_PER_PMD PTRS_PER_PMD +#endif + +#ifndef MAX_PTRS_PER_PUD +#define MAX_PTRS_PER_PUD PTRS_PER_PUD +#endif + extern unsigned char kasan_early_shadow_page[PAGE_SIZE]; -extern pte_t kasan_early_shadow_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS]; -extern pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD]; -extern pud_t kasan_early_shadow_pud[PTRS_PER_PUD]; +extern pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]; +extern pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD]; +extern pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD]; extern p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D]; int kasan_populate_early_shadow(const void *shadow_start, diff --git a/mm/kasan/init.c b/mm/kasan/init.c index 348f31d15a97..cc64ed6858c6 100644 --- a/mm/kasan/init.c +++ b/mm/kasan/init.c @@ -41,7 +41,7 @@ static inline bool kasan_p4d_table(pgd_t pgd) } #endif #if CONFIG_PGTABLE_LEVELS > 3 -pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss; +pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss; static inline bool kasan_pud_table(p4d_t p4d) { return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud)); @@ -53,7 +53,7 @@ static inline bool kasan_pud_table(p4d_t p4d) } #endif #if CONFIG_PGTABLE_LEVELS > 2 -pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss; +pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss; static inline bool kasan_pmd_table(pud_t pud) { return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd)); @@ -64,7 +64,7 @@ static inline bool kasan_pmd_table(pud_t pud) return false; } #endif -pte_t kasan_early_shadow_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS] +pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS] __page_aligned_bss; static inline bool kasan_pte_table(pmd_t pmd) From patchwork Tue Jun 15 01:47:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Axtens X-Patchwork-Id: 12320387 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 34894C2B9F4 for ; Tue, 15 Jun 2021 01:47:30 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CDC516140B for ; 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dkim=pass header.d=axtens.net header.s=google header.b=X0nswPKS; dmarc=none; spf=pass (imf16.hostedemail.com: domain of dja@axtens.net designates 209.85.215.177 as permitted sender) smtp.mailfrom=dja@axtens.net X-Stat-Signature: qmeqduk8f7ihgxkwe8zkj43kfhmhb3kx X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E21BB801934C X-HE-Tag: 1623721639-802356 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: KASAN is supported on 32-bit powerpc and the docs should reflect this. Suggested-by: Christophe Leroy Reviewed-by: Christophe Leroy Signed-off-by: Daniel Axtens --- Documentation/dev-tools/kasan.rst | 8 ++++++-- Documentation/powerpc/kasan.txt | 12 ++++++++++++ 2 files changed, 18 insertions(+), 2 deletions(-) create mode 100644 Documentation/powerpc/kasan.txt diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 83ec4a556c19..05d2d428a332 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -36,7 +36,8 @@ Both software KASAN modes work with SLUB and SLAB memory allocators, while the hardware tag-based KASAN currently only supports SLUB. Currently, generic KASAN is supported for the x86_64, arm, arm64, xtensa, s390, -and riscv architectures, and tag-based KASAN modes are supported only for arm64. +and riscv architectures. It is also supported on 32-bit powerpc kernels. +Tag-based KASAN modes are supported only for arm64. Usage ----- @@ -343,7 +344,10 @@ CONFIG_KASAN_VMALLOC With ``CONFIG_KASAN_VMALLOC``, KASAN can cover vmalloc space at the cost of greater memory usage. Currently, this is supported on x86, -riscv, s390, and powerpc. +riscv, s390, and 32-bit powerpc. + +It is optional, except on 32-bit powerpc kernels with module support, +where it is required. This works by hooking into vmalloc and vmap and dynamically allocating real shadow memory to back the mappings. diff --git a/Documentation/powerpc/kasan.txt b/Documentation/powerpc/kasan.txt new file mode 100644 index 000000000000..26bb0e8bb18c --- /dev/null +++ b/Documentation/powerpc/kasan.txt @@ -0,0 +1,12 @@ +KASAN is supported on powerpc on 32-bit only. + +32 bit support +============== + +KASAN is supported on both hash and nohash MMUs on 32-bit. + +The shadow area sits at the top of the kernel virtual memory space above the +fixmap area and occupies one eighth of the total kernel virtual memory space. + +Instrumentation of the vmalloc area is optional, unless built with modules, +in which case it is required. 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Mon, 14 Jun 2021 18:47:31 -0700 (PDT) Received: from localhost ([203.206.29.204]) by smtp.gmail.com with ESMTPSA id t62sm5508747pfc.189.2021.06.14.18.47.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Jun 2021 18:47:31 -0700 (PDT) From: Daniel Axtens To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, kasan-dev@googlegroups.com, christophe.leroy@csgroup.eu, aneesh.kumar@linux.ibm.com, bsingharora@gmail.com Cc: elver@google.com, Daniel Axtens Subject: [PATCH v12 5/6] powerpc/mm/kasan: rename kasan_init_32.c to init_32.c Date: Tue, 15 Jun 2021 11:47:04 +1000 Message-Id: <20210615014705.2234866-6-dja@axtens.net> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210615014705.2234866-1-dja@axtens.net> References: <20210615014705.2234866-1-dja@axtens.net> MIME-Version: 1.0 Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=axtens.net header.s=google header.b=ZeJTQLnh; dmarc=none; spf=pass (imf03.hostedemail.com: domain of dja@axtens.net designates 209.85.216.50 as permitted sender) smtp.mailfrom=dja@axtens.net X-Stat-Signature: riuae4djngic1w4fjg4frmmmad9fgxii X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1747FC00CBE0 X-HE-Tag: 1623721642-268585 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: kasan is already implied by the directory name, we don't need to repeat it. Suggested-by: Christophe Leroy Signed-off-by: Daniel Axtens --- arch/powerpc/mm/kasan/Makefile | 2 +- arch/powerpc/mm/kasan/{kasan_init_32.c => init_32.c} | 0 2 files changed, 1 insertion(+), 1 deletion(-) rename arch/powerpc/mm/kasan/{kasan_init_32.c => init_32.c} (100%) diff --git a/arch/powerpc/mm/kasan/Makefile b/arch/powerpc/mm/kasan/Makefile index bb1a5408b86b..42fb628a44fd 100644 --- a/arch/powerpc/mm/kasan/Makefile +++ b/arch/powerpc/mm/kasan/Makefile @@ -2,6 +2,6 @@ KASAN_SANITIZE := n -obj-$(CONFIG_PPC32) += kasan_init_32.o +obj-$(CONFIG_PPC32) += init_32.o obj-$(CONFIG_PPC_8xx) += 8xx.o obj-$(CONFIG_PPC_BOOK3S_32) += book3s_32.o diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/init_32.c similarity index 100% rename from arch/powerpc/mm/kasan/kasan_init_32.c rename to arch/powerpc/mm/kasan/init_32.c From patchwork Tue Jun 15 01:47:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Axtens X-Patchwork-Id: 12320391 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 11516C2B9F4 for ; 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dkim=pass header.d=axtens.net header.s=google header.b=BUcj6Ti4; dmarc=none; spf=pass (imf21.hostedemail.com: domain of dja@axtens.net designates 209.85.216.48 as permitted sender) smtp.mailfrom=dja@axtens.net X-HE-Tag: 1623721644-429882 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: [I'm hoping to get this in a subsequent merge window after we get the core changes in. I know there are still a few outstanding review comments, I just wanted to make sure that I supplied a real use-case for the core changes I'm proposing.] Implement a limited form of KASAN for Book3S 64-bit machines running under the Radix MMU, supporting only outline mode. - Enable the compiler instrumentation to check addresses and maintain the shadow region. (This is the guts of KASAN which we can easily reuse.) - Require kasan-vmalloc support to handle modules and anything else in vmalloc space. - KASAN needs to be able to validate all pointer accesses, but we can't instrument all kernel addresses - only linear map and vmalloc. On boot, set up a single page of read-only shadow that marks all iomap and vmemmap accesses as valid. - Document KASAN in both generic and powerpc docs. Background ---------- KASAN support on Book3S is a bit tricky to get right: - It would be good to support inline instrumentation so as to be able to catch stack issues that cannot be caught with outline mode. - Inline instrumentation requires a fixed offset. - Book3S runs code with translations off ("real mode") during boot, including a lot of generic device-tree parsing code which is used to determine MMU features. [ppc64 mm note: The kernel installs a linear mapping at effective address c000...-c008.... This is a one-to-one mapping with physical memory from 0000... onward. Because of how memory accesses work on powerpc 64-bit Book3S, a kernel pointer in the linear map accesses the same memory both with translations on (accessing as an 'effective address'), and with translations off (accessing as a 'real address'). This works in both guests and the hypervisor. For more details, see s5.7 of Book III of version 3 of the ISA, in particular the Storage Control Overview, s5.7.3, and s5.7.5 - noting that this KASAN implementation currently only supports Radix.] - Some code - most notably a lot of KVM code - also runs with translations off after boot. - Therefore any offset has to point to memory that is valid with translations on or off. One approach is just to give up on inline instrumentation. This way boot-time checks can be delayed until after the MMU is set is up, and we can just not instrument any code that runs with translations off after booting. Take this approach for now and require outline instrumentation. Previous attempts allowed inline instrumentation. However, they came with some unfortunate restrictions: only physically contiguous memory could be used and it had to be specified at compile time. Maybe we can do better in the future. Cc: Aneesh Kumar K.V # ppc64 hash version Cc: Christophe Leroy # ppc32 version Originally-by: Balbir Singh # ppc64 out-of-line radix version Signed-off-by: Daniel Axtens --- Documentation/dev-tools/kasan.rst | 11 +-- Documentation/powerpc/kasan.txt | 48 +++++++++- arch/powerpc/Kconfig | 4 +- arch/powerpc/Kconfig.debug | 3 +- arch/powerpc/include/asm/book3s/64/hash.h | 4 + arch/powerpc/include/asm/book3s/64/pgtable.h | 4 + arch/powerpc/include/asm/book3s/64/radix.h | 13 ++- arch/powerpc/include/asm/kasan.h | 22 +++++ arch/powerpc/kernel/Makefile | 11 +++ arch/powerpc/kernel/process.c | 16 ++-- arch/powerpc/kvm/Makefile | 5 ++ arch/powerpc/mm/book3s64/Makefile | 9 ++ arch/powerpc/mm/kasan/Makefile | 1 + arch/powerpc/mm/kasan/init_book3s_64.c | 95 ++++++++++++++++++++ arch/powerpc/mm/ptdump/ptdump.c | 20 ++++- arch/powerpc/platforms/Kconfig.cputype | 1 + arch/powerpc/platforms/powernv/Makefile | 6 ++ arch/powerpc/platforms/pseries/Makefile | 3 + 18 files changed, 257 insertions(+), 19 deletions(-) create mode 100644 arch/powerpc/mm/kasan/init_book3s_64.c diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 05d2d428a332..f8d6048db1bb 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -36,8 +36,9 @@ Both software KASAN modes work with SLUB and SLAB memory allocators, while the hardware tag-based KASAN currently only supports SLUB. Currently, generic KASAN is supported for the x86_64, arm, arm64, xtensa, s390, -and riscv architectures. It is also supported on 32-bit powerpc kernels. -Tag-based KASAN modes are supported only for arm64. +and riscv architectures. It is also supported on powerpc for 32-bit kernels and +for 64-bit kernels running under the Radix MMU. Tag-based KASAN modes are +supported only for arm64. Usage ----- @@ -344,10 +345,10 @@ CONFIG_KASAN_VMALLOC With ``CONFIG_KASAN_VMALLOC``, KASAN can cover vmalloc space at the cost of greater memory usage. Currently, this is supported on x86, -riscv, s390, and 32-bit powerpc. +riscv, s390, and powerpc. -It is optional, except on 32-bit powerpc kernels with module support, -where it is required. +It is optional, except on 64-bit powerpc kernels, and on 32-bit +powerpc kernels with module support, where it is required. This works by hooking into vmalloc and vmap and dynamically allocating real shadow memory to back the mappings. diff --git a/Documentation/powerpc/kasan.txt b/Documentation/powerpc/kasan.txt index 26bb0e8bb18c..f032b4eaf205 100644 --- a/Documentation/powerpc/kasan.txt +++ b/Documentation/powerpc/kasan.txt @@ -1,4 +1,4 @@ -KASAN is supported on powerpc on 32-bit only. +KASAN is supported on powerpc on 32-bit and Radix 64-bit only. 32 bit support ============== @@ -10,3 +10,49 @@ fixmap area and occupies one eighth of the total kernel virtual memory space. Instrumentation of the vmalloc area is optional, unless built with modules, in which case it is required. + +64 bit support +============== + +Currently, only the radix MMU is supported. There have been versions for hash +and Book3E processors floating around on the mailing list, but nothing has been +merged. + +KASAN support on Book3S is a bit tricky to get right: + + - It would be good to support inline instrumentation so as to be able to catch + stack issues that cannot be caught with outline mode. + + - Inline instrumentation requires a fixed offset. + + - Book3S runs code with translations off ("real mode") during boot, including a + lot of generic device-tree parsing code which is used to determine MMU + features. + + - Some code - most notably a lot of KVM code - also runs with translations off + after boot. + + - Therefore any offset has to point to memory that is valid with + translations on or off. + +One approach is just to give up on inline instrumentation. This way boot-time +checks can be delayed until after the MMU is set is up, and we can just not +instrument any code that runs with translations off after booting. This is the +current approach. + +To avoid this limitiation, the KASAN shadow would have to be placed inside the +linear mapping, using the same high-bits trick we use for the rest of the linear +mapping. This is tricky: + + - We'd like to place it near the start of physical memory. In theory we can do + this at run-time based on how much physical memory we have, but this requires + being able to arbitrarily relocate the kernel, which is basically the tricky + part of KASLR. Not being game to implement both tricky things at once, this + is hopefully something we can revisit once we get KASLR for Book3S. + + - Alternatively, we can place the shadow at the _end_ of memory, but this + requires knowing how much contiguous physical memory a system has _at compile + time_. This is a big hammer, and has some unfortunate consequences: inablity + to handle discontiguous physical memory, total failure to boot on machines + with less memory than specified, and that machines with more memory than + specified can't use it. This was deemed unacceptable. diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index dbccb0676e48..ff16af7022b1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -118,6 +118,7 @@ config PPC # Please keep this list sorted alphabetically. # select ARCH_32BIT_OFF_T if PPC32 + select ARCH_DISABLE_KASAN_INLINE if PPC_RADIX_MMU select ARCH_ENABLE_MEMORY_HOTPLUG select ARCH_ENABLE_MEMORY_HOTREMOVE select ARCH_HAS_COPY_MC if PPC64 @@ -191,7 +192,8 @@ config PPC select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14 - select HAVE_ARCH_KASAN_VMALLOC if PPC32 && PPC_PAGE_SHIFT <= 14 + select HAVE_ARCH_KASAN if PPC_RADIX_MMU + select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN select HAVE_ARCH_KFENCE if PPC32 select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 6342f9da4545..ad5b776a96e7 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -399,4 +399,5 @@ config PPC_FAST_ENDIAN_SWITCH config KASAN_SHADOW_OFFSET hex depends on KASAN - default 0xe0000000 + default 0xe0000000 if PPC32 + default 0xa80e000000000000 if PPC64 diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index d959b0195ad9..222669864ff6 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -18,6 +18,10 @@ #include #endif +#define H_PTRS_PER_PTE (1 << H_PTE_INDEX_SIZE) +#define H_PTRS_PER_PMD (1 << H_PMD_INDEX_SIZE) +#define H_PTRS_PER_PUD (1 << H_PUD_INDEX_SIZE) + /* Bits to set in a PMD/PUD/PGD entry valid bit*/ #define HASH_PMD_VAL_BITS (0x8000000000000000UL) #define HASH_PUD_VAL_BITS (0x8000000000000000UL) diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index a666d561b44d..49f2a2bbc0cf 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -232,6 +232,10 @@ extern unsigned long __pmd_frag_size_shift; #define PTRS_PER_PUD (1 << PUD_INDEX_SIZE) #define PTRS_PER_PGD (1 << PGD_INDEX_SIZE) +#define MAX_PTRS_PER_PTE ((H_PTRS_PER_PTE > R_PTRS_PER_PTE) ? H_PTRS_PER_PTE : R_PTRS_PER_PTE) +#define MAX_PTRS_PER_PMD ((H_PTRS_PER_PMD > R_PTRS_PER_PMD) ? H_PTRS_PER_PMD : R_PTRS_PER_PMD) +#define MAX_PTRS_PER_PUD ((H_PTRS_PER_PUD > R_PTRS_PER_PUD) ? H_PTRS_PER_PUD : R_PTRS_PER_PUD) + /* PMD_SHIFT determines what a second-level page table entry can map */ #define PMD_SHIFT (PAGE_SHIFT + PTE_INDEX_SIZE) #define PMD_SIZE (1UL << PMD_SHIFT) diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h index 59cab558e2f0..191399143dc8 100644 --- a/arch/powerpc/include/asm/book3s/64/radix.h +++ b/arch/powerpc/include/asm/book3s/64/radix.h @@ -35,6 +35,11 @@ #define RADIX_PMD_SHIFT (PAGE_SHIFT + RADIX_PTE_INDEX_SIZE) #define RADIX_PUD_SHIFT (RADIX_PMD_SHIFT + RADIX_PMD_INDEX_SIZE) #define RADIX_PGD_SHIFT (RADIX_PUD_SHIFT + RADIX_PUD_INDEX_SIZE) + +#define R_PTRS_PER_PTE (1 << RADIX_PTE_INDEX_SIZE) +#define R_PTRS_PER_PMD (1 << RADIX_PMD_INDEX_SIZE) +#define R_PTRS_PER_PUD (1 << RADIX_PUD_INDEX_SIZE) + /* * Size of EA range mapped by our pagetables. */ @@ -68,11 +73,11 @@ * * * 3rd quadrant expanded: - * +------------------------------+ + * +------------------------------+ Highest address (0xc010000000000000) + * +------------------------------+ KASAN shadow end (0xc00fc00000000000) * | | * | | - * | | - * +------------------------------+ Kernel vmemmap end (0xc010000000000000) + * +------------------------------+ Kernel vmemmap end/shadow start (0xc00e000000000000) * | | * | 512TB | * | | @@ -126,6 +131,8 @@ #define RADIX_VMEMMAP_SIZE RADIX_KERN_MAP_SIZE #define RADIX_VMEMMAP_END (RADIX_VMEMMAP_START + RADIX_VMEMMAP_SIZE) +/* For the sizes of the shadow area, see kasan.h */ + #ifndef __ASSEMBLY__ #define RADIX_PTE_TABLE_SIZE (sizeof(pte_t) << RADIX_PTE_INDEX_SIZE) #define RADIX_PMD_TABLE_SIZE (sizeof(pmd_t) << RADIX_PMD_INDEX_SIZE) diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h index 3c478e5ef24c..6efc822e70fd 100644 --- a/arch/powerpc/include/asm/kasan.h +++ b/arch/powerpc/include/asm/kasan.h @@ -30,9 +30,31 @@ #define KASAN_SHADOW_OFFSET ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET) +#ifdef CONFIG_PPC32 #define KASAN_SHADOW_END (-(-KASAN_SHADOW_START >> KASAN_SHADOW_SCALE_SHIFT)) +#endif #ifdef CONFIG_KASAN +#ifdef CONFIG_PPC_BOOK3S_64 +/* + * The shadow ends before the highest accessible address + * because we don't need a shadow for the shadow. Instead: + * c00e000000000000 << 3 + a80e000000000000 = c00fc00000000000 + */ +#define KASAN_SHADOW_END 0xc00fc00000000000UL + +DECLARE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key); + +static __always_inline bool kasan_arch_is_ready(void) +{ + if (static_branch_likely(&powerpc_kasan_enabled_key)) + return true; + return false; +} + +#define kasan_arch_is_ready kasan_arch_is_ready +#endif + void kasan_early_init(void); void kasan_mmu_init(void); void kasan_init(void); diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index f66b63e81c3b..aabac84106f1 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -32,6 +32,17 @@ KASAN_SANITIZE_early_32.o := n KASAN_SANITIZE_cputable.o := n KASAN_SANITIZE_prom_init.o := n KASAN_SANITIZE_btext.o := n +KASAN_SANITIZE_paca.o := n +KASAN_SANITIZE_setup_64.o := n +KASAN_SANITIZE_mce.o := n +KASAN_SANITIZE_mce_power.o := n + +# we have to be particularly careful in ppc64 to exclude code that +# runs with translations off, as we cannot access the shadow with +# translations off. However, ppc32 can sanitize this. +ifdef CONFIG_PPC64 +KASAN_SANITIZE_traps.o := n +endif ifdef CONFIG_KASAN CFLAGS_early_32.o += -DDISABLE_BRANCH_PROFILING diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 89e34aa273e2..430cf06f9406 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2151,8 +2151,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack, break; stack = (unsigned long *) sp; - newsp = stack[0]; - ip = stack[STACK_FRAME_LR_SAVE]; + newsp = READ_ONCE_NOCHECK(stack[0]); + ip = READ_ONCE_NOCHECK(stack[STACK_FRAME_LR_SAVE]); if (!firstframe || ip != lr) { printk("%s["REG"] ["REG"] %pS", loglvl, sp, ip, (void *)ip); @@ -2170,17 +2170,19 @@ void show_stack(struct task_struct *tsk, unsigned long *stack, * See if this is an exception frame. * We look for the "regshere" marker in the current frame. */ - if (validate_sp(sp, tsk, STACK_FRAME_WITH_PT_REGS) - && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { + if (validate_sp(sp, tsk, STACK_FRAME_WITH_PT_REGS) && + (READ_ONCE_NOCHECK(stack[STACK_FRAME_MARKER]) == + STACK_FRAME_REGS_MARKER)) { struct pt_regs *regs = (struct pt_regs *) (sp + STACK_FRAME_OVERHEAD); - lr = regs->link; + lr = READ_ONCE_NOCHECK(regs->link); printk("%s--- interrupt: %lx at %pS\n", - loglvl, regs->trap, (void *)regs->nip); + loglvl, READ_ONCE_NOCHECK(regs->trap), + (void *)READ_ONCE_NOCHECK(regs->nip)); __show_regs(regs); printk("%s--- interrupt: %lx\n", - loglvl, regs->trap); + loglvl, READ_ONCE_NOCHECK(regs->trap)); firstframe = 1; } diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile index 2bfeaa13befb..7f1592dacbeb 100644 --- a/arch/powerpc/kvm/Makefile +++ b/arch/powerpc/kvm/Makefile @@ -136,3 +136,8 @@ obj-$(CONFIG_KVM_BOOK3S_64_PR) += kvm-pr.o obj-$(CONFIG_KVM_BOOK3S_64_HV) += kvm-hv.o obj-y += $(kvm-book3s_64-builtin-objs-y) + +# KVM does a lot in real-mode, and 64-bit Book3S KASAN doesn't support that +ifdef CONFIG_PPC_BOOK3S_64 +KASAN_SANITIZE := n +endif diff --git a/arch/powerpc/mm/book3s64/Makefile b/arch/powerpc/mm/book3s64/Makefile index 1b56d3af47d4..a7d8a68bd2c5 100644 --- a/arch/powerpc/mm/book3s64/Makefile +++ b/arch/powerpc/mm/book3s64/Makefile @@ -21,3 +21,12 @@ obj-$(CONFIG_PPC_PKEY) += pkeys.o # Instrumenting the SLB fault path can lead to duplicate SLB entries KCOV_INSTRUMENT_slb.o := n + +# Parts of these can run in real mode and therefore are +# not safe with the current outline KASAN implementation +KASAN_SANITIZE_mmu_context.o := n +KASAN_SANITIZE_pgtable.o := n +KASAN_SANITIZE_radix_pgtable.o := n +KASAN_SANITIZE_radix_tlb.o := n +KASAN_SANITIZE_slb.o := n +KASAN_SANITIZE_pkeys.o := n diff --git a/arch/powerpc/mm/kasan/Makefile b/arch/powerpc/mm/kasan/Makefile index 42fb628a44fd..07eef87abd6c 100644 --- a/arch/powerpc/mm/kasan/Makefile +++ b/arch/powerpc/mm/kasan/Makefile @@ -5,3 +5,4 @@ KASAN_SANITIZE := n obj-$(CONFIG_PPC32) += init_32.o obj-$(CONFIG_PPC_8xx) += 8xx.o obj-$(CONFIG_PPC_BOOK3S_32) += book3s_32.o +obj-$(CONFIG_PPC_BOOK3S_64) += init_book3s_64.o diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c b/arch/powerpc/mm/kasan/init_book3s_64.c new file mode 100644 index 000000000000..ca913ed951a2 --- /dev/null +++ b/arch/powerpc/mm/kasan/init_book3s_64.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KASAN for 64-bit Book3S powerpc + * + * Copyright (C) 2019-2020 IBM Corporation + * Author: Daniel Axtens + */ + +#define DISABLE_BRANCH_PROFILING + +#include +#include +#include +#include +#include + +DEFINE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key); + +static void __init kasan_init_phys_region(void *start, void *end) +{ + unsigned long k_start, k_end, k_cur; + void *va; + + if (start >= end) + return; + + k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE); + k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE); + + va = memblock_alloc(k_end - k_start, PAGE_SIZE); + for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE) + map_kernel_page(k_cur, __pa(va), PAGE_KERNEL); +} + +void __init kasan_init(void) +{ + /* + * We want to do the following things: + * 1) Map real memory into the shadow for all physical memblocks + * This takes us from c000... to c008... + * 2) Leave a hole over the shadow of vmalloc space. KASAN_VMALLOC + * will manage this for us. + * This takes us from c008... to c00a... + * 3) Map the 'early shadow'/zero page over iomap and vmemmap space. + * This takes us up to where we start at c00e... + */ + + void *k_start = kasan_mem_to_shadow((void *)RADIX_VMALLOC_END); + void *k_end = kasan_mem_to_shadow((void *)RADIX_VMEMMAP_END); + phys_addr_t start, end; + u64 i; + pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL); + + if (!early_radix_enabled()) + panic("KASAN requires radix!"); + + for_each_mem_range(i, &start, &end) + kasan_init_phys_region((void *)start, (void *)end); + + for (i = 0; i < PTRS_PER_PTE; i++) + __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, + &kasan_early_shadow_pte[i], zero_pte, 0); + + for (i = 0; i < PTRS_PER_PMD; i++) + pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i], + kasan_early_shadow_pte); + + for (i = 0; i < PTRS_PER_PUD; i++) + pud_populate(&init_mm, &kasan_early_shadow_pud[i], + kasan_early_shadow_pmd); + + /* map the early shadow over the iomap and vmemmap space */ + kasan_populate_early_shadow(k_start, k_end); + + /* mark early shadow region as RO and wipe it */ + zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO); + for (i = 0; i < PTRS_PER_PTE; i++) + __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, + &kasan_early_shadow_pte[i], zero_pte, 0); + + /* + * clear_page relies on some cache info that hasn't been set up yet. + * It ends up looping ~forever and blows up other data. + * Use memset instead. + */ + memset(kasan_early_shadow_page, 0, PAGE_SIZE); + + static_branch_inc(&powerpc_kasan_enabled_key); + + /* Enable error messages */ + init_task.kasan_depth = 0; + pr_info("KASAN init done (64-bit Book3S)\n"); +} + +void __init kasan_late_init(void) { } diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index aca354fb670b..63672aa656e8 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -317,6 +318,23 @@ static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start) unsigned long addr; unsigned int i; +#if defined(CONFIG_KASAN) && defined(CONFIG_PPC_BOOK3S_64) + /* + * On radix + KASAN, we want to check for the KASAN "early" shadow + * which covers huge quantities of memory with the same set of + * read-only PTEs. If it is, we want to note the first page (to see + * the status change), and then note the last page. This gives us good + * results without spending ages noting the exact same PTEs over 100s of + * terabytes of memory. + */ + if (p4d_page(*p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud))) { + walk_pmd(st, pud, start); + addr = start + (PTRS_PER_PUD - 1) * PUD_SIZE; + walk_pmd(st, pud, addr); + return; + } +#endif + for (i = 0; i < PTRS_PER_PUD; i++, pud++) { addr = start + i * PUD_SIZE; if (!pud_none(*pud) && !pud_is_leaf(*pud)) @@ -387,11 +405,11 @@ static void populate_markers(void) #endif address_markers[i++].start_address = FIXADDR_START; address_markers[i++].start_address = FIXADDR_TOP; +#endif /* CONFIG_PPC64 */ #ifdef CONFIG_KASAN address_markers[i++].start_address = KASAN_SHADOW_START; address_markers[i++].start_address = KASAN_SHADOW_END; #endif -#endif /* CONFIG_PPC64 */ } static int ptdump_show(struct seq_file *m, void *v) diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 113431604035..de70bfea2982 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -105,6 +105,7 @@ config PPC_BOOK3S_64 select PPC_MM_SLICES select PPC_HAVE_KUEP select PPC_HAVE_KUAP + select KASAN_VMALLOC if KASAN config PPC_BOOK3E_64 bool "Embedded processors" diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile index be2546b96816..d50f6fc71ac6 100644 --- a/arch/powerpc/platforms/powernv/Makefile +++ b/arch/powerpc/platforms/powernv/Makefile @@ -1,4 +1,10 @@ # SPDX-License-Identifier: GPL-2.0 + +# nothing that deals with real mode is safe to KASAN +# in particular, idle code runs a bunch of things in real mode +KASAN_SANITIZE_idle.o := n +KASAN_SANITIZE_pci-ioda.o := n + obj-y += setup.o opal-call.o opal-wrappers.o opal.o opal-async.o obj-y += idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile index c8a2b0b05ac0..202199ef9e5c 100644 --- a/arch/powerpc/platforms/pseries/Makefile +++ b/arch/powerpc/platforms/pseries/Makefile @@ -30,3 +30,6 @@ obj-$(CONFIG_PPC_SVM) += svm.o obj-$(CONFIG_FA_DUMP) += rtas-fadump.o obj-$(CONFIG_SUSPEND) += suspend.o + +# nothing that operates in real mode is safe for KASAN +KASAN_SANITIZE_ras.o := n