From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752630Ab3LYDcy (ORCPT ); Tue, 24 Dec 2013 22:32:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:3471 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752222Ab3LYDcw (ORCPT ); Tue, 24 Dec 2013 22:32:52 -0500 Date: Wed, 25 Dec 2013 11:32:05 +0800 From: Dave Young To: Matt Fleming Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, x86@kernel.org, mjg59@srcf.ucam.org, hpa@zytor.com, James.Bottomley@HansenPartnership.com, vgoyal@redhat.com, ebiederm@xmission.com, horms@verge.net.au, kexec@lists.infradead.org, bp@alien8.de, greg@kroah.com, toshi.kani@hp.com, akpm@linux-foundation.org, mingo@kernel.org, msalter@redhat.com, leif.lindholm@linaro.org Subject: Re: [PATCH v7 09/12] efi: passing kexec necessary efi data via setup_data Message-ID: <20131225033205.GC6333@dhcp-16-126.nay.redhat.com> References: <1387533742-18018-1-git-send-email-dyoung@redhat.com> <1387533742-18018-10-git-send-email-dyoung@redhat.com> <20131221160416.GD29501@console-pimps.org> <20131223020958.GB3760@dhcp-16-126.nay.redhat.com> <20131223080741.GB28919@console-pimps.org> <20131225031259.GB6333@dhcp-16-126.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131225031259.GB6333@dhcp-16-126.nay.redhat.com> 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 On 12/25/13 at 11:12am, Dave Young wrote: > On 12/23/13 at 08:07am, Matt Fleming wrote: > > On Mon, 23 Dec, at 10:09:58AM, Dave Young wrote: > > > On 12/21/13 at 04:06pm, Matt Fleming wrote: > > > > On Fri, 20 Dec, at 06:02:19PM, Dave Young wrote: > > > > > @@ -133,6 +133,19 @@ extern void efi_sync_low_kernel_mappings(void); > > > > > extern void efi_setup_page_tables(void); > > > > > extern void __init old_map_region(efi_memory_desc_t *md); > > > > > > > > > > +struct efi_setup_data { > > > > > + u64 fw_vendor; > > > > > + u64 runtime; > > > > > + u64 tables; > > > > > + u64 smbios; > > > > > + u64 reserved[8]; > > > > > + efi_memory_desc_t map[0]; > > > > > +}; > > > > > > > > [...] > > > > > > > > > +static void get_nr_runtime_map(void) > > > > > +{ > > > > > + if (!efi_setup) > > > > > + return; > > > > > + > > > > > + nr_efi_runtime_map = (efi_data_len - sizeof(struct efi_setup_data)) / > > > > > + sizeof(efi_memory_desc_t); > > > > > +} > > > > > > > > Do we actually need the 'map' entry in efi_setup_data now that you're > > > > passing it via efi_info (which is much better approach!)? Also, we don't > > > > need the global nr_efi_runtime_map or efi_runtime_map variables now, > > > > right? > > > > > > The map is still necessary because we need store the map somewhere and pass > > > the physicall address to kexec kernel. Passing them in setup_data is the > > > only better way currently... > > > > > > In efi_info there's only an entry for the map physical address, the original > > > map area is not valid any more. > > > > Where do you dereference efi_setup_data.map* in the kexec kernel? > > The field itself is not dereferenced in kernel but it's still used in userspace > code for collecting and saving runtime maps. Since I still append the map at the > end of efi_setup_data so I think keep the map[0] is ok. What's your opinion? Matt, if you want to remove the map[0] please fold below one line patch? I have no strong opinion. Index: linux/arch/x86/include/asm/efi.h =================================================================== --- linux.orig/arch/x86/include/asm/efi.h +++ linux/arch/x86/include/asm/efi.h @@ -139,7 +139,6 @@ struct efi_setup_data { u64 tables; u64 smbios; u64 reserved[8]; - efi_memory_desc_t map[0]; }; extern u64 efi_setup;