Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753863AbbBTDfV (ORCPT ); Thu, 19 Feb 2015 22:35:21 -0500 Received: from mail-ig0-f175.google.com ([209.85.213.175]:65032 "EHLO mail-ig0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753512AbbBTDfU (ORCPT ); Thu, 19 Feb 2015 22:35:20 -0500 MIME-Version: 1.0 In-Reply-To: <20150220021306.GA2621@dhcp-17-102.nay.redhat.com> References: <1423015400-12629-1-git-send-email-yinghai@kernel.org> <20150211061148.GA4448@dhcp-17-102.nay.redhat.com> <20150218112956.GA1965@dhcp-17-102.nay.redhat.com> <20150220021306.GA2621@dhcp-17-102.nay.redhat.com> Date: Thu, 19 Feb 2015 19:35:19 -0800 X-Google-Sender-Auth: 9ZN--l0fCBHEo2M8IAknmWq30kY Message-ID: Subject: Re: [PATCH] x86, boot: Allow 64bit EFI kernel to be loaded above 4G From: Yinghai Lu To: Baoquan He , "H. Peter Anvin" Cc: Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1331 Lines: 37 On Thu, Feb 19, 2015 at 6:13 PM, Baoquan He wrote: > On 02/18/15 at 11:47am, Yinghai Lu wrote: > > Kaslr need both virtual and physical address be randomized, otherwise > it doesn't make sense. Please check what hpa said about this issue: > > https://lkml.org/lkml/2014/10/13/350 > If I read correctly, it could be separated. phy one could be on bootloader and virtual could be in kernel. > And usually no bootloader often load kernel onto a random physical > address. Fow now we can often see kexec/kdump did this. I believe Kees > introduced kaslr to mainly solve security issue of normal kernel which > is not like kexec/kdump for testing or debugging. Randomizing physical > address makes sense for kaslr feature. I put some grub2 patches that extend grub2 to load kernel/initrd above 4G into github tree. https://github.com/yhlu/grub2.git main purpose for that feature is to handle initrd that bigger than 4G. or you can try you solution on system that have 64bit EFI support, then you will don't need to worry about set ident mapping even. Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/