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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 847FBC4742C for ; Mon, 16 Nov 2020 17:41:25 +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 38DB8222E8 for ; Mon, 16 Nov 2020 17:41:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="3Wa2jKHC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38DB8222E8 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: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=vDHjei4wMCcTjh40eSRr8RPH2u7gUnJtYB/6dFyWlf8=; b=3Wa2jKHCp+PW1Wj4roJGe4xnp 4TdWKk/6dfj7+fRZ25NyU7h3SkYeJux8z1lle9V8PxGXELpL7IbcYuk4QVEznImRxbpX27IPfDeyB PUGEfh5wOpCJOOg1W2IA7GzR1VW0lPe/lHjmMMkD7++rSca6pIO9K14dokTl3uLG1oUjHk6g7ayh6 7drKkyWFBknt8PF1PD7XPaSDDllNkvxpUTrwlZU6HAspqmY8U2cR8ENSSMGtFwIOj4rdEfZyWD+0L Os5RDmQ68Znp8+tgLyNW2ZEDz3rqfTHeC+a7peUhniAAgf1cqoRger/TFFas86CBDIcrW3HoWCDo/ BDqDcLS7A==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1keiUp-0003qA-FC; Mon, 16 Nov 2020 17:40:55 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1keiUn-0003pp-73 for linux-arm-kernel@lists.infradead.org; Mon, 16 Nov 2020 17:40:54 +0000 Received: from trantor (unknown [2.26.170.190]) (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 1D25422265; Mon, 16 Nov 2020 17:40:50 +0000 (UTC) Date: Mon, 16 Nov 2020 17:40:48 +0000 From: Catalin Marinas To: Mark Rutland Subject: Re: [PATCHv4 14/17] arm64: uaccess: remove set_fs() Message-ID: References: <20201113124937.20574-1-mark.rutland@arm.com> <20201113124937.20574-15-mark.rutland@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201113124937.20574-15-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201116_124053_383049_6B96CA0B X-CRM114-Status: GOOD ( 11.02 ) 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: james.morse@arm.com, will@kernel.org, hch@lst.de, linux-arm-kernel@lists.infradead.org, robin.murphy@arm.com 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 Hi Mark, On Fri, Nov 13, 2020 at 12:49:34PM +0000, Mark Rutland wrote: > We no longer need to flip UAO to access kernel memory under KERNEL_DS, > and head.S unconditionally clears UAO for all kernel configurations via > an ERET in init_kernel_el. Thus, we don't need to dynamically flip UAO, > nor do we need to context-switch it. However, we do need to clear UAO > (and set PAN) during SDEI entry. If the kernel never sets the UAO bit, why do we need to clear it during SDEI entry? -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel