From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753547AbcHQC0I (ORCPT ); Tue, 16 Aug 2016 22:26:08 -0400 Received: from hydra.tuxags.com ([64.13.172.54]:52204 "EHLO mail.tuxags.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752325AbcHQC0H (ORCPT ); Tue, 16 Aug 2016 22:26:07 -0400 Date: Tue, 16 Aug 2016 19:25:55 -0700 From: Matt Mullins To: Yinghai Lu Cc: Kees Cook , Ingo Molnar , Ingo Molnar , Baoquan He , "H. Peter Anvin" , Borislav Petkov , Vivek Goyal , Andy Lutomirski , Lasse Collin , Andrew Morton , Dave Young , LKML , Simon Glass Subject: Re: [PATCH 2/6] x86/boot: Move compressed kernel to end of decompression buffer Message-ID: <20160817022553.GA9962@hydra.tuxags.com> Mail-Followup-To: Yinghai Lu , Kees Cook , Ingo Molnar , Ingo Molnar , Baoquan He , "H. Peter Anvin" , Borislav Petkov , Vivek Goyal , Andy Lutomirski , Lasse Collin , Andrew Morton , Dave Young , LKML , Simon Glass References: <1461888548-32439-1-git-send-email-keescook@chromium.org> <1461888548-32439-3-git-send-email-keescook@chromium.org> <20160816040147.GA4492@hydra.tuxags.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 16, 2016 at 12:19:42PM -0700, Yinghai Lu wrote: > On Mon, Aug 15, 2016 at 9:01 PM, Matt Mullins wrote: > > > > This appears to have a negative effect on booting the Intel Edison platform, as > > it uses u-boot as its bootloader. u-boot does not copy the init_size parameter > > when booting a bzImage: it copies a fixed-size setup_header [1], and its > > definition of setup_header doesn't include the parameters beyond setup_data [2]. > > > > With a zero value for init_size, this calculates a %rsp value of 0x101ff9600. > > This causes the boot process to hard-stop at the immediately-following pushq, as > > this platform has no usable physical addresses above 4G. > > > > What are the options for getting this type of platform to function again? For > > now, kexec from a working Linux system does seem to be a work-around, but there > > appears to be other x86 hardware using u-boot: the chromium.org folks seem to be > > maintaining the u-boot x86 tree. > > > > [1] http://git.denx.de/?p=u-boot.git;a=blob;f=arch/x86/lib/zimage.c;h=1b33c771391f49ffe82864ff1582bdfd07e5e97d;hb=HEAD#l156 > > [2] http://git.denx.de/?p=u-boot.git;a=blob;f=arch/x86/include/asm/bootparam.h;h=140095117e5a2daef0a097c55f0ed10e08acc781;hb=HEAD#l24 > > Then should fix the u-boot about header_size assumption. I was hoping to avoid that, since the Edison's u-boot is 10,000-line patch atop the upstream -- I don't trust myself to build and flash one quite yet. If this turned out to affect Chromebooks, I'd spend more effort pushing for a kernel fix, but it seems that ChromeOS has a different kernel load procedure and doesn't use "zboot". For now, I'll probably just keep a local patch that hard-codes a value large enough to decompress and launch the kernel. I may turn that local patch into something gated by a Kconfig eventually, in hopes that users of the other x86 u-boot platforms will see it in a "make oldconfig" run.