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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 714C3C64E7B for ; Mon, 30 Nov 2020 17:58:22 +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 E213E206E3 for ; Mon, 30 Nov 2020 17:58:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="SMztYMUf"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="XmDjRpd6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E213E206E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=oC4kMelGOyXjJqcbfRj8z/9fLifBwyEMcJRIMLGkRAQ=; b=SMztYMUfvDyKe7bmw44ZQHNBd gXIOm0dJ/0r6+4RCmVHraGjdj7l23LzNxcNLrFRx9yBt+9C3VwORo2HKl08Logyjm9f4/MlR853ji isL2hzn/a0YCXLzgTjFsb2UoBpSX1nHCwnQq+rTkF9eUIRI4xe/aASjc85lrj3XEPMzP8kbJiArjx d31iS7OSYRYbE2DGKhEW2jrZvzurPu3mV9PWT2L7xEVAb2bbJrY45M2QblEbCaebJaMZNRuNMiQPa SOZeYY1wdVmUoyiuYJUqBBFBjSN1CdOZXkz4KeNOmHzX5tuz6wBkax2atJU3qdNcUzfyGldFka7Ki Gbt9xZ3Fw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kjnQK-0007QE-LZ; Mon, 30 Nov 2020 17:57:16 +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 1kjnQI-0007Pb-8f for linux-arm-kernel@lists.infradead.org; Mon, 30 Nov 2020 17:57:15 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (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 C7F57206E3; Mon, 30 Nov 2020 17:57:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606759033; bh=zAn0U39uj2gW7KHPapxndRa/sHkW/TfgOLMEtCLmEaM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XmDjRpd66b8EbduMPVQB7tYz6biMwawTv/Ts3eBO+4iR2AinDnfaxEmyZ/IB2plbC FZUyPivcgpHis+LM08Q8fYpLJieg4CamOuskqhpbI1wj499I3AoJv57yGPcdCgVXvn PrgJiUyAMpcsV0c9teBA8YGvJE9kbQaza7+pRPzo= Date: Mon, 30 Nov 2020 17:57:07 +0000 From: Will Deacon To: Rongwei Wang Subject: Re: [PATCH 0/3] arm64:msr: Add MSR driver Message-ID: <20201130175706.GA25457@willie-the-truck> References: <20201130174833.41315-1-rongwei.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201130174833.41315-1-rongwei.wang@linux.alibaba.com> 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-20201130_125714_402492_A1E9EF36 X-CRM114-Status: GOOD ( 13.28 ) 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: gshan@redhat.com, geert+renesas@glider.be, Anson.Huang@nxp.com, catalin.marinas@arm.com, masahiroy@kernel.org, linux-kernel@vger.kernel.org, michael@walle.cc, krzk@kernel.org, bjorn.andersson@linaro.org, vkoul@kernel.org, olof@lixom.net, vincenzo.frascino@arm.com, shawnguo@kernel.org, ardb@kernel.org, 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 Tue, Dec 01, 2020 at 01:48:30AM +0800, Rongwei Wang wrote: > MSR ARM driver aims to provide interfacs for user to read or write data to all > system registers. Its functions is same as MSR driver (x86 platform). It mainly > depends on kprobe and undef exception to read or write system registers > dynamicly. ... but why? These are privileged registers for a reason, and giving userspace access to them is bound to cause serious problems. Why can't we do whatever it is that userspace is trying to do by poking these things in the kernel instead? This interface is a bit like using /dev/mem instead of writing a proper device driver. Thanks, Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel