Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754768AbeAIRRE (ORCPT + 1 other); Tue, 9 Jan 2018 12:17:04 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:60024 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751421AbeAIRRD (ORCPT ); Tue, 9 Jan 2018 12:17:03 -0500 Date: Tue, 9 Jan 2018 09:17:00 -0800 From: Christoph Hellwig To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, lorenzo.pieralisi@arm.com, christoffer.dall@linaro.org, linux-kernel@vger.kernel.org, shankerd@codeaurora.org, jnair@caviumnetworks.com Subject: Re: [PATCH v3 02/13] arm64: Kconfig: Reword UNMAP_KERNEL_AT_EL0 kconfig entry Message-ID: <20180109171700.GA18100@infradead.org> References: <1515432758-26440-1-git-send-email-will.deacon@arm.com> <1515432758-26440-3-git-send-email-will.deacon@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1515432758-26440-3-git-send-email-will.deacon@arm.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Mon, Jan 08, 2018 at 05:32:27PM +0000, Will Deacon wrote: > Although CONFIG_UNMAP_KERNEL_AT_EL0 does make KASLR more robust, it's > actually more useful as a mitigation against speculation attacks that > can leak arbitrary kernel data to userspace through speculation. > > Reword the Kconfig help message to reflect this, and make the option > depend on EXPERT so that it is on by default for the majority of users. I still haven't heard an anwer on why this isn't using CONFIG_PAGE_TABLE_ISOLATION but instead reinvents its own symbol.