From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.skyhub.de ([2a01:4f8:120:8448::d00d]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VofvA-0005HE-Js for kexec@lists.infradead.org; Thu, 05 Dec 2013 20:53:20 +0000 Date: Thu, 5 Dec 2013 21:52:50 +0100 From: Borislav Petkov Subject: Re: [PATCH v4 07/12] efi: passing kexec necessary efi data via setup_data Message-ID: <20131205205250.GF14407@pd.tnic> References: <20131129091415.GH4186@dhcp-16-126.nay.redhat.com> <1386023600.1791.201.camel@misato.fc.hp.com> <1386034289.1791.210.camel@misato.fc.hp.com> <20131203015613.GB3980@dhcp-16-126.nay.redhat.com> <1386085140.1791.218.camel@misato.fc.hp.com> <20131204024610.GA3764@dhcp-16-126.nay.redhat.com> <1386175428.1791.225.camel@misato.fc.hp.com> <20131205015615.GC3736@dhcp-16-126.nay.redhat.com> <20131205115124.GC14407@pd.tnic> <1386258962.1791.268.camel@misato.fc.hp.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1386258962.1791.268.camel@misato.fc.hp.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Toshi Kani , Dave Young Cc: mjg59@srcf.ucam.org, linux-efi@vger.kernel.org, matt@console-pimps.org, greg@kroah.com, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, James.Bottomley@HansenPartnership.com, horms@verge.net.au, ebiederm@xmission.com, hpa@zytor.com, vgoyal@redhat.com On Thu, Dec 05, 2013 at 08:56:02AM -0700, Toshi Kani wrote: > The smbios in efi_setup_data is necessary for kexec to pass the physical > address of the SMBIOS table from the 1st kernel to the 2nd kernel. > > The kernel boot sequence proceeds in the following order. Step 2 > requires efi.smbios to be the physical address. However, Dave found > that EFI system table has a virtual address of SMBIOS in step 1. Hence, > he sets it back to the physical address with the smbios in > efi_setup_data. (When it is still the physical address, it simply sets > the same value.) > > 1. efi_init() - Set efi.smbios from EFI system table > 2. dmi_scan_machine() - Temporary map efi.smbios to access SMBIOS table > 3. efi_enter_virtual_mode() - Map EFI ranges Thanks Toshi, it is all clear now. @Dave: you might want to put Toshi's explanation in the commit message of your patch so that we know *why* the change is needed. Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec