Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755026AbbDOA25 (ORCPT ); Tue, 14 Apr 2015 20:28:57 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:34476 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751768AbbDOA2u (ORCPT ); Tue, 14 Apr 2015 20:28:50 -0400 Message-ID: <552DB0BE.5020305@amacapital.net> Date: Tue, 14 Apr 2015 17:28:46 -0700 From: Andy Lutomirski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Alexander Kuleshov , linux-kernel@vger.kernel.org Subject: Re: x86_64: Question about fixmaps References: In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1072 Lines: 29 On 04/14/2015 06:16 AM, Alexander Kuleshov wrote: > Hello All, > > I'm reading x86_64 source code and trying to understand where are > fixmaps space in the virtual memory space. If I understand correctly > (but i'm really not sure about it), fixmap space is after vsyscall > space. As Documentation/x86/x86_64/mm.txt says vsyscall virtual space > is: > > ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls > > With 'earlyprintk' i got FIXADDR_START and FIXADDR_TOP and they are: > > FIXADDR_START - 0xffffffffff779000L > FIXADDR_TOP - 0xffffffffff7ff000L > > with these addressess FIXADDR_START/FIXADDR_TOP overlap vsyscalls > area. Is it correct case that fixmaps are in vsyscal virtual memory > space or I'm wrong somewhere? It's the other way around. vsyscalls are in the fixmap. I should fix the docs. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/