From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [edk2] Corrupted EFI region Date: Wed, 7 Aug 2013 22:23:02 +0100 Message-ID: <20130807212302.GA10905@srcf.ucam.org> References: <51FFD5B0.9080000@redhat.com> <20130805164731.GG31845@pd.tnic> <52001896.1030509@redhat.com> <20130805220808.GC14067@pd.tnic> <20130806141036.GD14891@pd.tnic> <520116D1.2010000@redhat.com> <20130807151935.GJ17920@pd.tnic> <20130807201908.GG2515@console-pimps.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Andrew Fish Cc: Matt Fleming , edk2-devel@lists.sourceforge.net, Laszlo Ersek , linux-efi@vger.kernel.org, Gleb Natapov , lkml , David Woodhouse List-Id: linux-efi@vger.kernel.org On Wed, Aug 07, 2013 at 02:10:28PM -0700, Andrew Fish wrote: > Well the issue I see is I don't think OS X or Windows are doing this. > So I'm guessing there is some unique thing beings done on the Linux > side and we don't have good tests to catch bugs in the EFI > implementations. If the Linux loader hides the bugs and we don't hit > them with other operating systems they are never going to get fixed. > It would be good if we could track down some of these issues and make > a request for some tests that can help catch these issues. The tests > would be part of UEFI.org, but since some of us play in both worlds we > can forward the known issues to the UEFI test work group. Linux enables NX before calling SetVirtualAddressMap(). If other OSes don't do that, you probably won't see the bug. > Is it possible to have a switch to turn off the not required behavior > (hiding EFI implementation bugs) so that bad platforms could be > detected? This would be a good thing to try on platforms at the > upcoming UEFI Plugfest hosted by the Linux Foundation and the UEFI > Forum, so the bad behavior can be detected and the vendors can fix the > issue. It's behaviour that we already have to work around due to shipping hardware exhibiting it, so while we could certainly develop a test, Linux is always going to need to include the workaround code. That being said, some of what we do with the memory map in Linux right now is probably unnecessary - we're modifying the memory map because that's a convenient place to store the information, rather than because the memory map actually needs to be modified. We could do a better job of that. -- Matthew Garrett | mjg59@srcf.ucam.org