Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752126AbXIPUqh (ORCPT ); Sun, 16 Sep 2007 16:46:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752541AbXIPUqb (ORCPT ); Sun, 16 Sep 2007 16:46:31 -0400 Received: from rv-out-0910.google.com ([209.85.198.189]:48781 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752119AbXIPUqa (ORCPT ); Sun, 16 Sep 2007 16:46:30 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Ww/f3W96rDSPsTK+L34fJVan6o1AtUbY3iBnSatto/3OuK3JmQ/YYIykNbEpCKLoaomSpsBie8DakxIcxNBi10pBIoF85hI5QHtuKxnxkxSkpkVlF4CUXPTHe8i85clBUPlOWBsO+bEinjhh9t9R7koSUoLZCHoDke8+QqpQl3c= Message-ID: Date: Sun, 16 Sep 2007 13:46:29 -0700 From: "Ulrich Drepper" To: "Francis Moreau" Subject: Re: x86_64: vsyscall vs vdso Cc: linux-kernel@vger.kernel.org In-Reply-To: <38b2ab8a0709161324p6841c1f9h6f9422b0e6c4b5cd@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <38b2ab8a0709161324p6841c1f9h6f9422b0e6c4b5cd@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1266 Lines: 27 On 9/16/07, Francis Moreau wrote: > I'm a bit puzzled because vdso doesn't seem to be used on my fedora 7: > I just compiled a trivial program which just call gettimeofday() and > ld.so resolves this call with vsyscall's gettimeofday. > > Now I'm wondering when vdso is used, could anybody give me a clue ? F7 was released before the vdso for x86_64 was upstream so you should not expect anything else. F8 will use the available vdso. This doesn't just happen magically, changes to libc are needed. > Another question: is vdso going to replace vsyscall at all ? If so how > are statically programs going to be handled ? Unfortunately the vsyscalls cannot ever go completely away. Statically linked apps, the bane of progress, will need them. There are also people updating kernels but not the user userland code. What we will have to do in future is to make vsyscalls configurable. Both a compile time option and a runtime option (perhaps also under control of SELinux) are likely needed. - 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/