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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 DA26FC433E0 for ; Mon, 8 Feb 2021 16:58:06 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 763D964E56 for ; Mon, 8 Feb 2021 16:58:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 763D964E56 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=OINJnXB+dLTegeYLGxAxFMU/1ztM7mR6EC0fw/RodqA=; b=szqJfuTTXz/yBRNws1NA3/jnj yKrEjR4xw3UeGllSgD1NR/xn/+6g0tmvgCthCySq2ZPHC+nwCAWAMNrbA/nigVF+szpK0J0nydgFU rJVcWpAQkaeArTeQkzOktXLGeF+Uohcnjave3K1H2675YlIztSJBO7nXy0zyH/A+xbSW/gT95kZB2 etXHzBYJN9I4AdSBWQ8GN32G1GIOnzS8VZEXf5Rvc2OKfkuTPHQhObWaQXvu0LNzl8Dfr5ndkYrVB NbW9JrcH1Dc4PUaaesY3nKYvmCUOJ/bR4Iz/tES3C7WiU/LLBuUPIJGmipSVlv3m3oD5hc7PL/kNO s3cshBwlQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l99qO-0005Cc-EG; Mon, 08 Feb 2021 16:57:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l99q2-00055I-H1 for linux-arm-kernel@lists.infradead.org; Mon, 08 Feb 2021 16:56:40 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 03B4D139F; Mon, 8 Feb 2021 08:56:38 -0800 (PST) Received: from e119884-lin.cambridge.arm.com (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 218AA3F719; Mon, 8 Feb 2021 08:56:36 -0800 (PST) From: Vincenzo Frascino To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH v12 5/7] arm64: mte: Enable async tag check fault Date: Mon, 8 Feb 2021 16:56:15 +0000 Message-Id: <20210208165617.9977-6-vincenzo.frascino@arm.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210208165617.9977-1-vincenzo.frascino@arm.com> References: <20210208165617.9977-1-vincenzo.frascino@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210208_115638_864574_3DA965D3 X-CRM114-Status: GOOD ( 20.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marco Elver , Lorenzo Pieralisi , Catalin Marinas , Branislav Rankov , Alexander Potapenko , Evgenii Stepanov , Andrey Konovalov , Andrey Ryabinin , Andrew Morton , Vincenzo Frascino , Will Deacon , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org MTE provides a mode that asynchronously updates the TFSR_EL1 register when a tag check exception is detected. To take advantage of this mode the kernel has to verify the status of the register at: 1. Context switching 2. Return to user/EL0 (Not required in entry from EL0 since the kernel did not run) 3. Kernel entry from EL1 4. Kernel exit to EL1 If the register is non-zero a trace is reported. Add the required features for EL1 detection and reporting. Note: ITFSB bit is set in the SCTLR_EL1 register hence it guaranties that the indirect writes to TFSR_EL1 are synchronized at exception entry to EL1. On the context switch path the synchronization is guarantied by the dsb() in __switch_to(). The dsb(nsh) in mte_check_tfsr_exit() is provisional pending confirmation by the architects. Cc: Catalin Marinas Cc: Will Deacon Reviewed-by: Catalin Marinas Acked-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino --- arch/arm64/include/asm/mte.h | 32 ++++++++++++++++++++++++++++ arch/arm64/kernel/entry-common.c | 6 ++++++ arch/arm64/kernel/mte.c | 36 ++++++++++++++++++++++++++++++++ 3 files changed, 74 insertions(+) diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index d02aff9f493d..237bb2f7309d 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -92,5 +92,37 @@ static inline void mte_assign_mem_tag_range(void *addr, size_t size) #endif /* CONFIG_ARM64_MTE */ +#ifdef CONFIG_KASAN_HW_TAGS +void mte_check_tfsr_el1(void); + +static inline void mte_check_tfsr_entry(void) +{ + mte_check_tfsr_el1(); +} + +static inline void mte_check_tfsr_exit(void) +{ + /* + * The asynchronous faults are sync'ed automatically with + * TFSR_EL1 on kernel entry but for exit an explicit dsb() + * is required. + */ + dsb(nsh); + isb(); + + mte_check_tfsr_el1(); +} +#else +static inline void mte_check_tfsr_el1(void) +{ +} +static inline void mte_check_tfsr_entry(void) +{ +} +static inline void mte_check_tfsr_exit(void) +{ +} +#endif /* CONFIG_KASAN_HW_TAGS */ + #endif /* __ASSEMBLY__ */ #endif /* __ASM_MTE_H */ diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 5346953e4382..31666511ba67 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -37,6 +37,8 @@ static void noinstr enter_from_kernel_mode(struct pt_regs *regs) lockdep_hardirqs_off(CALLER_ADDR0); rcu_irq_enter_check_tick(); trace_hardirqs_off_finish(); + + mte_check_tfsr_entry(); } /* @@ -47,6 +49,8 @@ static void noinstr exit_to_kernel_mode(struct pt_regs *regs) { lockdep_assert_irqs_disabled(); + mte_check_tfsr_exit(); + if (interrupts_enabled(regs)) { if (regs->exit_rcu) { trace_hardirqs_on_prepare(); @@ -243,6 +247,8 @@ asmlinkage void noinstr enter_from_user_mode(void) asmlinkage void noinstr exit_to_user_mode(void) { + mte_check_tfsr_exit(); + trace_hardirqs_on_prepare(); lockdep_hardirqs_on_prepare(CALLER_ADDR0); user_enter_irqoff(); diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index 60531afc706e..3332aabda466 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -192,6 +192,29 @@ bool mte_report_once(void) return READ_ONCE(report_fault_once); } +#ifdef CONFIG_KASAN_HW_TAGS +void mte_check_tfsr_el1(void) +{ + u64 tfsr_el1; + + if (!system_supports_mte()) + return; + + tfsr_el1 = read_sysreg_s(SYS_TFSR_EL1); + + if (unlikely(tfsr_el1 & SYS_TFSR_EL1_TF1)) { + /* + * Note: isb() is not required after this direct write + * because there is no indirect read subsequent to it + * (per ARM DDI 0487F.c table D13-1). + */ + write_sysreg_s(0, SYS_TFSR_EL1); + + kasan_report_async(); + } +} +#endif + static void update_sctlr_el1_tcf0(u64 tcf0) { /* ISB required for the kernel uaccess routines */ @@ -257,6 +280,19 @@ void mte_thread_switch(struct task_struct *next) /* avoid expensive SCTLR_EL1 accesses if no change */ if (current->thread.sctlr_tcf0 != next->thread.sctlr_tcf0) update_sctlr_el1_tcf0(next->thread.sctlr_tcf0); + else + isb(); + + /* + * Check if an async tag exception occurred at EL1. + * + * Note: On the context switch path we rely on the dsb() present + * in __switch_to() to guarantee that the indirect writes to TFSR_EL1 + * are synchronized before this point. + * isb() above is required for the same reason. + * + */ + mte_check_tfsr_el1(); } void mte_suspend_exit(void) -- 2.30.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel