From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH v2 1/3] x86, boot: add mmio serial during compressed boot Date: Tue, 16 Jul 2013 12:36:09 -0700 Message-ID: <51E5A0A9.90108@zytor.com> References: <1373659660-31123-1-git-send-email-keescook@chromium.org> <20130712203802.GA14702@www.outflux.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from terminus.zytor.com ([198.137.202.10]:58183 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933110Ab3GPTgb (ORCPT ); Tue, 16 Jul 2013 15:36:31 -0400 In-Reply-To: Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Kees Cook Cc: Yinghai Lu , "Eric W. Biederman" , Linux Kernel Mailing List , Rob Landley , Thomas Gleixner , Ingo Molnar , the arch/x86 maintainers , Greg Kroah-Hartman , "linux-doc@vger.kernel.org" , linux-serial@vger.kernel.org On 07/16/2013 12:31 PM, Kees Cook wrote: > > Could the first step be documenting the limitation? I've found this > patch extremely useful for my case already, and I imagine there might > be other people that need the early mmio stuff to. Generally the > compressed boot serial console stuff is going to be used in the more > common non-kexec situations at least for a while. > > Does this patch create any _problems_? Right now, neither low nor >4G > kernel can use an mmio serial port. :) This this, we'd at least gain > it for the low case. > Even documenting the limitation is likely to end up with a bunch of emails asking why their kernel crashed. I think setting up a dynamic #PF handler is the right thing for the decompressor, we already did for the kernel proper. -hpa