From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758849Ab3CDV44 (ORCPT ); Mon, 4 Mar 2013 16:56:56 -0500 Received: from mail.skyhub.de ([78.46.96.112]:41362 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758158Ab3CDV4z (ORCPT ); Mon, 4 Mar 2013 16:56:55 -0500 Date: Mon, 4 Mar 2013 22:56:39 +0100 From: Borislav Petkov To: Andy Lutomirski Cc: X86 ML , LKML Subject: Re: [PATCH 3/5] x86-64, docs, mm: Add vsyscall range to virtual address space layout Message-ID: <20130304215639.GH22274@pd.tnic> Mail-Followup-To: Borislav Petkov , Andy Lutomirski , X86 ML , LKML References: <1362428180-8865-1-git-send-email-bp@alien8.de> <1362428180-8865-4-git-send-email-bp@alien8.de> <513515F0.7050603@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <513515F0.7050603@mit.edu> 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 Mon, Mar 04, 2013 at 01:45:20PM -0800, Andy Lutomirski wrote: > vsyscalls are only 4k. Am I missing something obvious her? Right, but we're reserving 5 level2 pages for this, i.e. 5*512*4K = 10M. I.e., each level2 page contains 512 ptes, each pointing to a 4K page. arch/x86/kernel/head_64.S: ... NEXT_PAGE(level2_fixmap_pgt) .fill 506,8,0 .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */ .fill 5,8,0 NEXT_PAGE(level1_fixmap_pgt) .fill 512,8,0 -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --