From owner-freebsd-arm@freebsd.org Thu Sep 10 12:58:29 2015 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4D066A01BE0 for ; Thu, 10 Sep 2015 12:58:29 +0000 (UTC) (envelope-from prvs=688ac6705=Ian.Campbell@citrix.com) Received: from SMTP.CITRIX.COM (smtp.citrix.com [66.165.176.89]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "mail.citrix.com", Issuer "Verizon Public SureServer CA G14-SHA2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id ED07D1C40 for ; Thu, 10 Sep 2015 12:58:28 +0000 (UTC) (envelope-from prvs=688ac6705=Ian.Campbell@citrix.com) X-IronPort-AV: E=Sophos;i="5.17,504,1437436800"; d="scan'208";a="299154478" Message-ID: <1441889905.24450.382.camel@citrix.com> Subject: Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters From: Ian Campbell To: Mark Rutland , Stefano Stabellini CC: "devicetree@vger.kernel.org" , "linux-efi@vger.kernel.org" , "linux-doc@vger.kernel.org" , "daniel.kiper@oracle.com" , "ard.biesheuvel@linaro.org" , "linux-kernel@vger.kernel.org" , "leif.lindholm@linaro.org" , "xen-devel@lists.xen.org" , "julien.grall@citrix.com" , "freebsd-arm@freebsd.org" , "matt.fleming@intel.com" , "christoffer.dall@linaro.org" , "jbeulich@suse.com" , Shannon Zhao , "peter.huangpeng@huawei.com" , "linux-arm-kernel@lists.infradead.org" , "shannon.zhao@linaro.org" Date: Thu, 10 Sep 2015 13:58:25 +0100 In-Reply-To: <20150910121514.GE29293@leverpostej> References: <1441874516-11364-1-git-send-email-zhaoshenglong@huawei.com> <20150910095208.GA29293@leverpostej> <20150910112418.GC29293@leverpostej> <20150910121514.GE29293@leverpostej> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-DLP: MIA1 X-Mailman-Approved-At: Thu, 10 Sep 2015 13:17:02 +0000 X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Sep 2015 12:58:29 -0000 On Thu, 2015-09-10 at 13:15 +0100, Mark Rutland wrote: > > In any case this should be separate from the shim ABI discussion. > > I disagree; I think this is very much relevant to the ABI discussion. > That's not to say that I insist on a particular approach, but I think > that they need to be considered together. Taking a step back, the reason for using the EFI stub parameters is only (AFAIK) in order to be able to locate the ACPI RDSP (the root table pointer), which as it happens is normally passed via one of the EFI firmware tables. If there was a way to achieve that goal (i.e. another way to find the RSDP) without opening the can of UEFI worms then we could consider that opiton too. a way != the legacy x86 thing of scanning low memory of the signature, of course. Ian.