From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Date: Thu, 10 Sep 2015 07:08:50 -0600 Message-ID: <55F19D0202000078000A1B54__17631.9294413135$1441890646$gmane$org@prv-mh.provo.novell.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1441889905.24450.382.camel@citrix.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: Mark Rutland , "devicetree@vger.kernel.org" , "matt.fleming@intel.com" , Stefano Stabellini , "linux-kernel@vger.kernel.org" , "daniel.kiper@oracle.com" , "ard.biesheuvel@linaro.org" , "linux-doc@vger.kernel.org" , "peter.huangpeng@huawei.com" , "leif.lindholm@linaro.org" , "xen-devel@lists.xen.org" , "julien.grall@citrix.com" , "freebsd-arm@freebsd.org" , "linux-efi@vger.kernel.org" , "shannon.zhao@linaro.org" , Shannon Zhao , christoffer.dall@linaro List-Id: xen-devel@lists.xenproject.org >>> On 10.09.15 at 14:58, wrote: > 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. 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