Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755329AbbDNNQR (ORCPT ); Tue, 14 Apr 2015 09:16:17 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:37542 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753805AbbDNNQJ (ORCPT ); Tue, 14 Apr 2015 09:16:09 -0400 MIME-Version: 1.0 Date: Tue, 14 Apr 2015 19:16:08 +0600 Message-ID: Subject: x86_64: Question about fixmaps From: Alexander Kuleshov To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 912 Lines: 25 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? Thank you. -- 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/