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=-8.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 9A3C4C2BBD1 for ; Thu, 17 Sep 2020 14:16:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55BAB2078D for ; Thu, 17 Sep 2020 14:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727212AbgIQOQi (ORCPT ); Thu, 17 Sep 2020 10:16:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:58118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727235AbgIQOKr (ORCPT ); Thu, 17 Sep 2020 10:10:47 -0400 Received: from gaia (unknown [31.124.44.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 785E62065C; Thu, 17 Sep 2020 14:03:40 +0000 (UTC) Date: Thu, 17 Sep 2020 15:03:37 +0100 From: Catalin Marinas To: Andrey Konovalov Cc: Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com, Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 24/37] arm64: mte: Add in-kernel tag fault handler Message-ID: <20200917140337.GC10662@gaia> References: <7866d9e6f11f12f1bad42c895bf4947addba71c2.1600204505.git.andreyknvl@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7866d9e6f11f12f1bad42c895bf4947addba71c2.1600204505.git.andreyknvl@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 15, 2020 at 11:16:06PM +0200, Andrey Konovalov wrote: > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index a3bd189602df..cdc23662691c 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -294,6 +295,18 @@ static void die_kernel_fault(const char *msg, unsigned long addr, > do_exit(SIGKILL); > } > > +static void report_tag_fault(unsigned long addr, unsigned int esr, > + struct pt_regs *regs) > +{ > + bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0; > + > + pr_alert("Memory Tagging Extension Fault in %pS\n", (void *)regs->pc); > + pr_alert(" %s at address %lx\n", is_write ? "Write" : "Read", addr); > + pr_alert(" Pointer tag: [%02x], memory tag: [%02x]\n", > + mte_get_ptr_tag(addr), > + mte_get_mem_tag((void *)addr)); > +} > + > static void __do_kernel_fault(unsigned long addr, unsigned int esr, > struct pt_regs *regs) > { > @@ -641,10 +654,31 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) > return 0; > } > > +static void do_tag_recovery(unsigned long addr, unsigned int esr, > + struct pt_regs *regs) > +{ > + report_tag_fault(addr, esr, regs); I'd only report this once since we expect it to be disabled lazily on the other CPUs (i.e. just use a "static bool reported" to keep track). > + > + /* > + * Disable Memory Tagging Extension Tag Checking on the local CPU Too verbose, just say MTE tag checking, people reading this code should have learnt already what MTE stands for ;). > + * for the current EL. > + * It will be done lazily on the other CPUs when they will hit a > + * tag fault. > + */ > + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_NONE); > + isb(); > +} > + > + > static int do_tag_check_fault(unsigned long addr, unsigned int esr, > struct pt_regs *regs) > { > - do_bad_area(addr, esr, regs); > + /* The tag check fault (TCF) is per TTBR */ > + if (is_ttbr0_addr(addr)) > + do_bad_area(addr, esr, regs); > + else > + do_tag_recovery(addr, esr, regs); This part looks fine now. -- Catalin