From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH 1/4] Documentation: arm: [U]EFI runtime services Date: Thu, 27 Jun 2013 02:32:19 +0100 Message-ID: <20130627013219.GA346@srcf.ucam.org> References: <1372183863-11333-1-git-send-email-leif.lindholm@linaro.org> <1372183863-11333-2-git-send-email-leif.lindholm@linaro.org> <51CA2B03.4080106@wwwdotorg.org> <20130626135311.GA9078@rocoto.smurfnet.nu> <20130626135933.GQ22026@console-pimps.org> <1372257499.2168.5.camel@dabdike> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1372257499.2168.5.camel@dabdike> Sender: linux-kernel-owner@vger.kernel.org To: James Bottomley Cc: Matt Fleming , Leif Lindholm , Grant Likely , Stephen Warren , "linux-arm-kernel@lists.infradead.org" , linux-efi@vger.kernel.org, "linux-doc@vger.kernel.org" , Linux Kernel Mailing List , "patches@linaro.org" , "H. Peter Anvin" , Thomas Gleixner , matt.fleming@intel.com List-Id: linux-efi@vger.kernel.org On Wed, Jun 26, 2013 at 07:38:19AM -0700, James Bottomley wrote: > The fixed virtual address scheme currently being looked at for x86_64 to > make SetVirtualAddressMap() kexec invariant doesn't work on 32 bit > because the address space isn't big enough. For ARM, given that we've > much more opportunity to work with the vendors, can we just avoid > transitioning to a virtual address map and always just install a > physical mapping before doing efi calls? We can probably get away with that now, but it does risk us ending up with some firmware that expects to run in physical mode (boards designed for Linux) and some firmware that expects to run in virtual mode (boards designed for Windows). The degree of lockdown in the Windows ecosystem at present means it's not a real problem at the moment, but if that ever changes we're going to risk incompatibility. -- Matthew Garrett | mjg59@srcf.ucam.org