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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 00ACAC54FCB for ; Wed, 22 Apr 2020 17:27:57 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 CD2AD20776 for ; Wed, 22 Apr 2020 17:27:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="r0MSLrH3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD2AD20776 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+infradead-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=bombadil.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=1BDAvCw8Y+ypEQd/Sc/DY5gOSidk1qIA3BOhyvHylDE=; b=r0MSLrH3P/SP/n rbUfsop5ulGnPSmzn8duIB0/kavPPkoYYRuV9ljDLbVBSY4yTg57+BQiwazJgn1ORvp/wuXcobPWn l5D+z13QHeZh7CyCLwO85MnQzZy+NrZ22SCkynRVGiYkk49YogbGZnBnOfriiHatCDKB9tWEaNtOb H4nbW5k1+beXf0lSYFyXDHM7/U+c9B2pu8CB6aEtfsSuOtE4VNcQsl74uJ7bg2GG1pDeSXxqItX4b hC+QZ2XVW4rT1d+/DeM1DC0Fyqhg/u+3BVydpzjipkAGVfAAR833JuDmU4wKVcKobKX8U5eA0EHAL mN6ctPaEDuTndkOkfdWg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRJA7-0007fo-TS; Wed, 22 Apr 2020 17:27:51 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRJA4-0007f8-Mg for linux-arm-kernel@lists.infradead.org; Wed, 22 Apr 2020 17:27:50 +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 E5E701FB; Wed, 22 Apr 2020 10:27:47 -0700 (PDT) Received: from gaia (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1AEBA3F6CF; Wed, 22 Apr 2020 10:27:46 -0700 (PDT) Date: Wed, 22 Apr 2020 18:27:43 +0100 From: Catalin Marinas To: Mark Brown Subject: Re: [PATCH 0/3] arm64: Make NOP handling a whitelist Message-ID: <20200422172743.GG3585@gaia> References: <20200324194822.15682-1-broonie@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200324194822.15682-1-broonie@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200422_102748_784714_1515DE2E X-CRM114-Status: GOOD ( 11.46 ) 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 , Amit Daniel Kachhap , 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+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Mar 24, 2020 at 07:48:19PM +0000, Mark Brown wrote: > Currently we default to assuming any unrecognized instruction in the > hint space can be safely handled as a NOP. This is not robust and any > code that really wants a NOP should be using the explicitly defined NOP > so let's instead invert this and whitelist those instructions which it > is safe to handle as NOPs. > > Mark Brown (3): > arm64: insn: Don't assume unrecognized HINTs are NOPs > arm64: insn: Add constants for PAC and BTI instruction decode > arm64: insn: Report PAC and BTI instructions as NOPs > > arch/arm64/include/asm/insn.h | 22 ++++++++++++++++++++-- > arch/arm64/kernel/insn.c | 32 ++++++++++++++++++++++++-------- > 2 files changed, 44 insertions(+), 10 deletions(-) IIRC, we concluded [1] there is no problem for PAC and BTI instruction in the NOP space. For this series: Acked-by: Catalin Marinas [1] https://lore.kernel.org/linux-arm-kernel/20200312184211.GA3849205@arrakis.emea.arm.com/ -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel