Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753637AbaFPOIx (ORCPT ); Mon, 16 Jun 2014 10:08:53 -0400 Received: from mail-we0-f169.google.com ([74.125.82.169]:55468 "EHLO mail-we0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953AbaFPOIv (ORCPT ); Mon, 16 Jun 2014 10:08:51 -0400 MIME-Version: 1.0 In-Reply-To: <20140616023604.GI5714@two.firstfloor.org> References: <21405.44257.742122.786960@gargle.gargle.HOWL> <20140615143500.GP179@brightrain.aerifal.cx> <539DD26B.3060709@zytor.com> <539DDE9C.3010903@zytor.com> <20140616023604.GI5714@two.firstfloor.org> Date: Mon, 16 Jun 2014 07:08:50 -0700 X-Google-Sender-Auth: LW7GysbNPu1TCcVa-pE2G4QxsSg Message-ID: Subject: Re: [RFC 0/2] __vdso_findsym From: Ian Lance Taylor To: Andi Kleen Cc: Andy Lutomirski , "H. Peter Anvin" , Rich Felker , Mikael Pettersson , Russ Cox , Linux API , "linux-kernel@vger.kernel.org" , X86 ML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 15, 2014 at 7:36 PM, Andi Kleen wrote: > > I haven't looked into this in detail, but my initial assumption would > be that it wouldn't be useful to add new vdso interfaces just for Go. > After all would you really want to force ever Go user to upgrade their > kernel just to get fast fime? So it has to work with whatever is already > there anyways. Go works fine with the current interface. There was, arguably, a bug in Go's old implementation in that it assumed that the vDSO would have a normal symbol table. That bug has already been fixed. I think this issue started when some of the Go developers questioned why the kernel needed to provide a very complex interface--parsing an ELF shared shared library--for very simple functionality--looking up the address of a magic function. This approach has required special support not just in Go, but also in the dynamic linker and gdb, and does not work well for statically linked binaries. The support in gdb is perhaps a good idea, but elsewhere it does not make sense. So why not provide a simple interface? Ian -- 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/