From owner-freebsd-arm@freebsd.org Thu Sep 10 13:08:54 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 6DC9EA0010F for ; Thu, 10 Sep 2015 13:08:54 +0000 (UTC) (envelope-from JBeulich@suse.com) Received: from prv-mh.provo.novell.com (prv-mh.provo.novell.com [137.65.248.74]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "*.provo.novell.com", Issuer "DigiCert SHA2 High Assurance Server CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 3D67410AD for ; Thu, 10 Sep 2015 13:08:53 +0000 (UTC) (envelope-from JBeulich@suse.com) Received: from INET-PRV-MTA by prv-mh.provo.novell.com with Novell_GroupWise; Thu, 10 Sep 2015 07:08:52 -0600 Message-Id: <55F19D0202000078000A1B54@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.0.1 Date: Thu, 10 Sep 2015 07:08:50 -0600 From: "Jan Beulich" To: "Ian Campbell" Cc: "Mark Rutland" , "julien.grall@citrix.com" , "Stefano Stabellini" , "freebsd-arm@freebsd.org" , "peter.huangpeng@huawei.com" , "Shannon Zhao" , "matt.fleming@intel.com" , "ard.biesheuvel@linaro.org" , "christoffer.dall@linaro.org" , "leif.lindholm@linaro.org" , "shannon.zhao@linaro.org" , "linux-arm-kernel@lists.infradead.org" , "xen-devel@lists.xen.org" , "daniel.kiper@oracle.com" , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-efi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters References: <1441874516-11364-1-git-send-email-zhaoshenglong@huawei.com> <20150910095208.GA29293@leverpostej> <20150910112418.GC29293@leverpostej> <20150910121514.GE29293@leverpostej> <1441889905.24450.382.camel@citrix.com> In-Reply-To: <1441889905.24450.382.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-Mailman-Approved-At: Thu, 10 Sep 2015 13:17:40 +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 13:08:54 -0000 >>> On 10.09.15 at 14:58, wrote: > On Thu, 2015-09-10 at 13:15 +0100, Mark Rutland wrote: >=20 >> > In any case this should be separate from the shim ABI discussion. >>=20 >> 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. >=20 > 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. >=20 > 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. >=20 > a way !=3D the legacy x86 thing of scanning low memory of the signature, = of > course. But even x86 doesn't do that (other than as a fallback) on EFI. The configuration table is available to Dom0 (via XENPF_firmware_info: XEN_FW_EFI_INFO:XEN_FW_EFI_CONFIG_TABLE). Jan