From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751469AbaFMFjs (ORCPT ); Fri, 13 Jun 2014 01:39:48 -0400 Received: from terminus.zytor.com ([198.137.202.10]:43663 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750963AbaFMFjr (ORCPT ); Fri, 13 Jun 2014 01:39:47 -0400 Message-ID: <539A8E89.5000602@zytor.com> Date: Thu, 12 Jun 2014 22:39:21 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Andy Lutomirski CC: "linux-kernel@vger.kernel.org" , X86 ML , Russ Cox , Ian Taylor Subject: Re: vdso feature requests from the Go people References: <539A890A.5090206@zytor.com> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/12/2014 10:23 PM, Andy Lutomirski wrote: > > As far as I know, there's no reliable way to just read the dynsym > table -- the thing doesn't have a specified length, which is what > broke Go in the first place. > Ah yes, you're right. > > Parsing the ELF dynamic tables is kind of annoyingly complicated, and > understanding the format is a real PITA -- the documentation I've been > able to find is outright terrible. > Yes... not entirely clear that putting it in the vdso is a net win, though. There are some people who would like to put a significant chunk of libc in the vdso, and it just doesn't seem like a good idea. An index table is somewhat more reasonable, but (a) not backwards compatible (so wouldn't work with older kernels) and (b) has shades of Windows... -hpa