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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 538A1C43142 for ; Tue, 31 Jul 2018 09:26:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 091FA208A4 for ; Tue, 31 Jul 2018 09:26:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 091FA208A4 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731500AbeGaLFx (ORCPT ); Tue, 31 Jul 2018 07:05:53 -0400 Received: from foss.arm.com ([217.140.101.70]:50756 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729731AbeGaLFx (ORCPT ); Tue, 31 Jul 2018 07:05:53 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4FEAD7A9; Tue, 31 Jul 2018 02:26:28 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 208F03F5BA; Tue, 31 Jul 2018 02:26:28 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id F3B781AE30AF; Tue, 31 Jul 2018 10:26:29 +0100 (BST) Date: Tue, 31 Jul 2018 10:26:29 +0100 From: Will Deacon To: James Morse Cc: Bhupesh Sharma , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, bhupesh.linux@gmail.com, takahiro.akashi@linaro.org, catalin.marinas@arm.com, Ard Biesheuvel , Mark Rutland Subject: Re: [PATCH v2] arm64, kaslr: export offset in VMCOREINFO ELF notes Message-ID: <20180731092629.GD4680@arm.com> References: <1532931883-16132-1-git-send-email-bhsharma@redhat.com> <303e32f7-ff47-ea9b-d5a0-45a22e44d0a9@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <303e32f7-ff47-ea9b-d5a0-45a22e44d0a9@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 31, 2018 at 10:19:35AM +0100, James Morse wrote: > Hi Bhupesh, > > On 30/07/18 07:24, Bhupesh Sharma wrote: > > Include KASLR offset in arm64 VMCOREINFO ELF notes to assist in > > debugging. vmcore parsing in user-space already expects this value in > > the notes and we are providing it for portability of those existing > > tools with x86. > > > > Ideally we would like core code to do this (so that way this > > information won't be missed when an architecture adds KASLR support), > > but mips has CONFIG_RANDOMIZE_BASE, and doesn't provide kaslr_offset(), > > so I am not sure if this is needed for mips (and other such similar arch > > cases in future). So, lets keep this architecture specific for now. > > (heh, I assumed you would rewrite my train-of-thought, but I guess this works!) > > > > As an example of a user-space use-case, consider the > > makedumpfile user-space utility which will need fixup to use this > > KASLR offset to work with cases where we need to find a way to > > translate symbol address from vmlinux to kernel run time address > > in case of KASLR boot on arm64. > > Acked-by: James Morse > > If we want to send this to stable, it looks like it should have been part of the > KASLR series, f80fb3a3d5084 ("arm64: add support for kernel ASLR") was merged > for v4.6. > CC: # 4.6.x Hmm, does this warrant a stable backport? This hasn't ever worked, right? Will