Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752129Ab3FZOFK (ORCPT ); Wed, 26 Jun 2013 10:05:10 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:51355 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751539Ab3FZOFH (ORCPT ); Wed, 26 Jun 2013 10:05:07 -0400 Date: Wed, 26 Jun 2013 16:04:59 +0200 From: Leif Lindholm To: Grant Likely Cc: "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 Subject: Re: [PATCH 1/4] Documentation: arm: [U]EFI runtime services Message-ID: <20130626140459.GB9078@rocoto.smurfnet.nu> References: <1372183863-11333-1-git-send-email-leif.lindholm@linaro.org> <1372183863-11333-2-git-send-email-leif.lindholm@linaro.org> 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 Content-Length: 2449 Lines: 63 On Wed, Jun 26, 2013 at 02:13:39PM +0100, Grant Likely wrote: > > diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt > > +It (early) parses the FDT for the following parameters: > > Need to state which node these properties can be found in. I recommend /chosen Will do. > I would also prefix all of the following properties with "linux," > since they are very much about what the Linux kernel needs for > booting. EFI stub will be creating these properties specifically for > Linux, and the LinuxLoader should do the same (until we eventually > kill it). And that. > > +- 'efi-system-table': > > + Physical address of the system table. (required) > > Need to mention the size of this address. Is it 64 bit or 32 bit? I > would follow the lead of 'linux,initrd-start' here and make the size > of property the size of the address. ie. If it is 8 bytes long, then > it is a 64 bit address. Currently, it's a 4-byte address. Although technically possible to be >32-bit in an LPAE system, the 1:1 mappign requirement of the UEFI spec forces it to reside in the lower 4GB on a 32-bit system. > > +- 'efi-runtime-mmap': > > + Physical address of an EFI memory map, containing at least > > + the regions to be preserved. (required) > > +- 'efi-runtime-mmap-size': > > + Size in bytes of the provided memory map. (required) > > I would collapse the above two properties into a single property that > actually contains the memory map instead of pointing to it. You will > also need to specify the exact format of the data in this property. Ok, that makes sense. Hmm. The data is an array of struct EFI_MEMORY_DESCRIPTOR entries, known in Linux as efi_memory_desc_t. Is that a good enough description? > > +- 'efi-mmap-desc-size': > > + Size of each descriptor in the memory map. (override default) > > +- 'efi-mmap-desc-ver': > > + Memory descriptor format version. (override default) > > I don't understand how these properties will actually work. What > changes in the parsing if these properties are set? I guess the intended use is that these options would permit you to append new fields to the struct and have old code correctly parse the array anyway. / Leif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/