From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752889AbbI3A4p (ORCPT ); Tue, 29 Sep 2015 20:56:45 -0400 Received: from terminus.zytor.com ([198.137.202.10]:49746 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751695AbbI3A4n (ORCPT ); Tue, 29 Sep 2015 20:56:43 -0400 Subject: Re: [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions To: Matt Fleming , Borislav Petkov References: <1443218539-7610-1-git-send-email-matt@codeblueprint.co.uk> <1443218539-7610-3-git-send-email-matt@codeblueprint.co.uk> <20150926060159.GB25877@gmail.com> <20150927070644.GC26125@gmail.com> <20150927104014.GA7631@pd.tnic> <20150929143612.GC4401@codeblueprint.co.uk> Cc: Ingo Molnar , Ard Biesheuvel , Thomas Gleixner , "linux-kernel@vger.kernel.org" , "linux-efi@vger.kernel.org" , Leif Lindholm , Catalin Marinas , Will Deacon , "stable@vger.kernel.org" , Matt Fleming , Mark Rutland , Mark Salter , Linus Torvalds , Andrew Morton , Andy Lutomirski , Denys Vlasenko , Brian Gerst From: "H. Peter Anvin" Message-ID: <560B3327.9020801@zytor.com> Date: Tue, 29 Sep 2015 17:56:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150929143612.GC4401@codeblueprint.co.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/29/2015 07:36 AM, Matt Fleming wrote: > > That's a pretty good summary for x86. I think specifically the reason > we map the EFI memmap entries "backwards" (entry N has higher VA than > entry N+1) is because the code was easier to write that way, but > you'll know better than me ;-) > There were two reasons: 1. The code was easier to write. 2. Windows did it that way. Windows apparently broke and was changed due to this feature, too. -hpa From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions Date: Tue, 29 Sep 2015 17:56:07 -0700 Message-ID: <560B3327.9020801@zytor.com> References: <1443218539-7610-1-git-send-email-matt@codeblueprint.co.uk> <1443218539-7610-3-git-send-email-matt@codeblueprint.co.uk> <20150926060159.GB25877@gmail.com> <20150927070644.GC26125@gmail.com> <20150927104014.GA7631@pd.tnic> <20150929143612.GC4401@codeblueprint.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150929143612.GC4401-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matt Fleming , Borislav Petkov Cc: Ingo Molnar , Ard Biesheuvel , Thomas Gleixner , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Leif Lindholm , Catalin Marinas , Will Deacon , "stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Matt Fleming , Mark Rutland , Mark Salter , Linus Torvalds , Andrew Morton , Andy Lutomirski , Denys Vlasenko , Brian Gerst List-Id: linux-efi@vger.kernel.org On 09/29/2015 07:36 AM, Matt Fleming wrote: > > That's a pretty good summary for x86. I think specifically the reason > we map the EFI memmap entries "backwards" (entry N has higher VA than > entry N+1) is because the code was easier to write that way, but > you'll know better than me ;-) > There were two reasons: 1. The code was easier to write. 2. Windows did it that way. Windows apparently broke and was changed due to this feature, too. -hpa