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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 C6C3EC433E0 for ; Wed, 29 Jul 2020 10:45:15 +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 8F5E7207E8 for ; Wed, 29 Jul 2020 10:45:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YDCuUHlD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F5E7207E8 Authentication-Results: mail.kernel.org; dmarc=none (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:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Bm2VSqxv2DlOBhntxr2jnTnpXiNjbE9ByX1uTP4qUEE=; b=YDCuUHlDWf9BbDPkJ3mat2ZHR QRUEsTQXDXezjCJcLSOxEUQrs8JDw7IDinyB53/WuVaQnGPBMAUVPRM2xmxFNVMIUQVw3OltbZUa3 JNbxjnkN6lOqGz5hBKO9OPUWs5CsFpHqGuqCsfIkKOZEbKomrX8LgWGDYOmW3nFVjIynKtFlXUrMx DQ5YBhUyu371+iOlwU+k9aWvLmbLnrC8DwBRrZXJ5TzFc9lc+s6mgfLOEdyx9lFjyF3D2JJ4RMns0 TsGZ5hiHyH0rwhgIy7VPHTjzIwjdkHeLIFhxFUWliRAGx3zXToWxUsWjr1oJ7qjemXKMXiJEDmzPq A4dq/YMjw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k0jYl-0004LC-3i; Wed, 29 Jul 2020 10:43:43 +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 1k0jYh-00048O-UJ for linux-arm-kernel@lists.infradead.org; Wed, 29 Jul 2020 10:43:41 +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 191FB30E; Wed, 29 Jul 2020 03:43:36 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BD4273F718; Wed, 29 Jul 2020 03:43:34 -0700 (PDT) Date: Wed, 29 Jul 2020 11:43:32 +0100 From: Dave Martin To: Amit Daniel Kachhap Subject: Re: [PATCH v4 3/4] arm64: kprobe: disable probe of fault prone ptrauth instruction Message-ID: <20200729104332.GD21941@arm.com> References: <1594368010-4419-1-git-send-email-amit.kachhap@arm.com> <1594368010-4419-4-git-send-email-amit.kachhap@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1594368010-4419-4-git-send-email-amit.kachhap@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200729_064340_580202_187A3399 X-CRM114-Status: GOOD ( 21.75 ) 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: Mark Rutland , Kees Cook , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Vincenzo Frascino , Will Deacon , linux-arm-kernel@lists.infradead.org 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 On Fri, Jul 10, 2020 at 01:30:09PM +0530, Amit Daniel Kachhap wrote: > With the addition of ARMv8.3-FPAC feature, the probe of authenticate > ptrauth instructions (AUT*) may cause ptrauth fault exception in case of > authenticate failure so they cannot be safely single stepped. > > Hence the probe of authenticate instructions is disallowed but the > corresponding pac ptrauth instruction (PAC*) is not affected and they can > still be probed. Also AUTH* instructions do not make sense at function > entry points so most realistic probes would be unaffected by this change. > > Signed-off-by: Amit Daniel Kachhap I take it we don't need any special handling of things like RETAA now that they are allowed to generate ptrauth faults? IIUC such instructions are already not simulated and not stepped out-of-line, so we probably don't need to do anything. Instructions like this won't appear at normal function entry points. Assuming what I've said above is correct: Reviewed-by: Dave Martin > --- > Changes since v3: > * Commit logs cleanup. > * Moved comment changes in a separate patch. > > arch/arm64/kernel/insn.c | 6 ------ > 1 file changed, 6 deletions(-) > > diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c > index a107375005bc..33d53cb46542 100644 > --- a/arch/arm64/kernel/insn.c > +++ b/arch/arm64/kernel/insn.c > @@ -60,16 +60,10 @@ bool __kprobes aarch64_insn_is_steppable_hint(u32 insn) > case AARCH64_INSN_HINT_XPACLRI: > case AARCH64_INSN_HINT_PACIA_1716: > case AARCH64_INSN_HINT_PACIB_1716: > - case AARCH64_INSN_HINT_AUTIA_1716: > - case AARCH64_INSN_HINT_AUTIB_1716: > case AARCH64_INSN_HINT_PACIAZ: > case AARCH64_INSN_HINT_PACIASP: > case AARCH64_INSN_HINT_PACIBZ: > case AARCH64_INSN_HINT_PACIBSP: > - case AARCH64_INSN_HINT_AUTIAZ: > - case AARCH64_INSN_HINT_AUTIASP: > - case AARCH64_INSN_HINT_AUTIBZ: > - case AARCH64_INSN_HINT_AUTIBSP: > case AARCH64_INSN_HINT_BTI: > case AARCH64_INSN_HINT_BTIC: > case AARCH64_INSN_HINT_BTIJ: > -- > 2.17.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel