From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Young Subject: Re: [PATCH] export efi.flags to sysfs Date: Thu, 29 May 2014 10:08:37 +0800 Message-ID: <20140529020837.GB2068@darkstar.nay.redhat.com> References: <20140526083935.GA19682@dhcp-16-198.nay.redhat.com> <20140527133411.GG10994@redhat.com> <20140528021359.GC2820@darkstar.nay.redhat.com> <20140528124029.GF14863@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20140528124029.GF14863-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Vivek Goyal Cc: matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-efi@vger.kernel.org On 05/28/14 at 08:40am, Vivek Goyal wrote: > On Wed, May 28, 2014 at 10:13:59AM +0800, Dave Young wrote: > > On 05/27/14 at 09:34am, Vivek Goyal wrote: > > > On Mon, May 26, 2014 at 04:39:35PM +0800, Dave Young wrote: > > > > > > > > For efi=old_map and any old_map quirks like SGI UV in current > > > > tree kexec/kdump will fail because it depends on the new 1:1 mapping. > > > > > > > > Thus export the mapping method to sysfs so kexec tools can switch > > > > to original way to boot. > > > > > > > > Since we have efi.flags for all efi facilities so let's just export the > > > > efi.flags itself, it maybe useful for other arches and use cases. > > > > > > > > > > Does it require any documentation in Documentation/ABI/.. > > > > Yes, it's necessary. Will do in next version. > > > > I'm still discussing with Matt, exporting efi.flags seems not a good way > > because they are more internal interfaces. > > > > Probably I should export only a file 'old_map' instead. > > How does /sys/firmware/efi/runtime-map/* look like with old mapping? Can't > we look at it and figure out if it is 1:1 or not. There's phys_addr and virt_addr, (virt_addr - phys_addr) will always be -64G for 1:1 map, ioremapped addresses space is different. So this is a good idea, we can do this way to avoid more ABI. Thanks Dave