From patchwork Tue Dec 22 20:01:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11987249 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 59B47C433DB for ; Tue, 22 Dec 2020 20:01:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E507C20795 for ; Tue, 22 Dec 2020 20:01:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E507C20795 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BC9978D0015; Tue, 22 Dec 2020 15:01:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B28508D0012; Tue, 22 Dec 2020 15:01:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F11F8D0015; Tue, 22 Dec 2020 15:01:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0108.hostedemail.com [216.40.44.108]) by kanga.kvack.org (Postfix) with ESMTP id 82E838D0012 for ; Tue, 22 Dec 2020 15:01:42 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 519198249980 for ; Tue, 22 Dec 2020 20:01:42 +0000 (UTC) X-FDA: 77621988444.29.beast99_0a0b97527462 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 6E650180868E0 for ; Tue, 22 Dec 2020 20:01:41 +0000 (UTC) X-HE-Tag: beast99_0a0b97527462 X-Filterd-Recvd-Size: 5962 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Tue, 22 Dec 2020 20:01:40 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 0B13222ADC; Tue, 22 Dec 2020 20:01:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608667299; bh=gh4y1Xk5AtcuXlMWZAg1eDaRrWbiCuy7OvwHp+REC6g=; h=Date:From:To:Subject:In-Reply-To:From; b=LlaZPQlMFAyuMjT7xYNTebh2VCknVxcPYy2WhqC76+VsNydGVqEnZ19XSY9z4icXA j8a8FJICKCOccNG0JT4dkYj/Q64xoNTCJVrxpXwjyeB1h2wOFb09GTccjtPXx9deXc b3WtakCyOsA+51v3ThvB10KlhE6UmhfwDTYEMWnw= Date: Tue, 22 Dec 2020 12:01:38 -0800 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, aryabinin@virtuozzo.com, Branislav.Rankov@arm.com, catalin.marinas@arm.com, dvyukov@google.com, elver@google.com, eugenis@google.com, glider@google.com, gor@linux.ibm.com, kevin.brodsky@arm.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, vincenzo.frascino@arm.com, will.deacon@arm.com Subject: [patch 27/60] arm64: kasan: allow enabling in-kernel MTE Message-ID: <20201222200138.aIQST2piJ%akpm@linux-foundation.org> In-Reply-To: <20201222115844.d30aaef7df6f5b120d3e0c3d@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: Vincenzo Frascino Subject: arm64: kasan: allow enabling in-kernel MTE Hardware tag-based KASAN relies on Memory Tagging Extension (MTE) feature and requires it to be enabled. MTE supports This patch adds a new mte_enable_kernel() helper, that enables MTE in Synchronous mode in EL1 and is intended to be called from KASAN runtime during initialization. The Tag Checking operation causes a synchronous data abort as a consequence of a tag check fault when MTE is configured in synchronous mode. As part of this change enable match-all tag for EL1 to allow the kernel to access user pages without faulting. This is required because the kernel does not have knowledge of the tags set by the user in a page. Note: For MTE, the TCF bit field in SCTLR_EL1 affects only EL1 in a similar way as TCF0 affects EL0. MTE that is built on top of the Top Byte Ignore (TBI) feature hence we enable it as part of this patch as well. Link: https://lkml.kernel.org/r/7352b0a0899af65c2785416c8ca6bf3845b66fa1.1606161801.git.andreyknvl@google.com Signed-off-by: Vincenzo Frascino Co-developed-by: Andrey Konovalov Signed-off-by: Andrey Konovalov Reviewed-by: Catalin Marinas Tested-by: Vincenzo Frascino Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Branislav Rankov Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Kevin Brodsky Cc: Marco Elver Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/include/asm/mte-kasan.h | 6 ++++++ arch/arm64/kernel/mte.c | 7 +++++++ arch/arm64/mm/proc.S | 23 ++++++++++++++++++++--- 3 files changed, 33 insertions(+), 3 deletions(-) --- a/arch/arm64/include/asm/mte-kasan.h~arm64-kasan-allow-enabling-in-kernel-mte +++ a/arch/arm64/include/asm/mte-kasan.h @@ -29,6 +29,8 @@ u8 mte_get_mem_tag(void *addr); u8 mte_get_random_tag(void); void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag); +void mte_enable_kernel(void); + #else /* CONFIG_ARM64_MTE */ static inline u8 mte_get_ptr_tag(void *ptr) @@ -49,6 +51,10 @@ static inline void *mte_set_mem_tag_rang return addr; } +static inline void mte_enable_kernel(void) +{ +} + #endif /* CONFIG_ARM64_MTE */ #endif /* __ASSEMBLY__ */ --- a/arch/arm64/kernel/mte.c~arm64-kasan-allow-enabling-in-kernel-mte +++ a/arch/arm64/kernel/mte.c @@ -129,6 +129,13 @@ void *mte_set_mem_tag_range(void *addr, return ptr; } +void mte_enable_kernel(void) +{ + /* Enable MTE Sync Mode for EL1. */ + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); + isb(); +} + static void update_sctlr_el1_tcf0(u64 tcf0) { /* ISB required for the kernel uaccess routines */ --- a/arch/arm64/mm/proc.S~arm64-kasan-allow-enabling-in-kernel-mte +++ a/arch/arm64/mm/proc.S @@ -40,9 +40,15 @@ #define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA #ifdef CONFIG_KASAN_SW_TAGS -#define TCR_KASAN_FLAGS TCR_TBI1 | TCR_TBID1 +#define TCR_KASAN_SW_FLAGS TCR_TBI1 | TCR_TBID1 #else -#define TCR_KASAN_FLAGS 0 +#define TCR_KASAN_SW_FLAGS 0 +#endif + +#ifdef CONFIG_KASAN_HW_TAGS +#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1 | TCR_TBI1 +#else +#define TCR_KASAN_HW_FLAGS 0 #endif /* @@ -427,6 +433,10 @@ SYM_FUNC_START(__cpu_setup) */ mov_q x5, MAIR_EL1_SET #ifdef CONFIG_ARM64_MTE + mte_tcr .req x20 + + mov mte_tcr, #0 + /* * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported * (ID_AA64PFR1_EL1[11:8] > 1). @@ -447,6 +457,9 @@ SYM_FUNC_START(__cpu_setup) /* clear any pending tag check faults in TFSR*_EL1 */ msr_s SYS_TFSR_EL1, xzr msr_s SYS_TFSRE0_EL1, xzr + + /* set the TCR_EL1 bits */ + mov_q mte_tcr, TCR_KASAN_HW_FLAGS 1: #endif msr mair_el1, x5 @@ -456,7 +469,11 @@ SYM_FUNC_START(__cpu_setup) */ mov_q x10, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \ TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \ - TCR_TBI0 | TCR_A1 | TCR_KASAN_FLAGS + TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS +#ifdef CONFIG_ARM64_MTE + orr x10, x10, mte_tcr + .unreq mte_tcr +#endif tcr_clear_errata_bits x10, x9, x5 #ifdef CONFIG_ARM64_VA_BITS_52