From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753086Ab2DKF7x (ORCPT ); Wed, 11 Apr 2012 01:59:53 -0400 Received: from mail-pz0-f52.google.com ([209.85.210.52]:41205 "EHLO mail-pz0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752720Ab2DKF7w (ORCPT ); Wed, 11 Apr 2012 01:59:52 -0400 Message-ID: <4F851DCB.7090304@gmail.com> Date: Wed, 11 Apr 2012 13:59:39 +0800 From: Li Yu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: A question about backport jump label Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, We want to backport jump label for 2.6.32 x86_64 kernel on RHEL5/RHEL6. Such two systems use old versions of gcc 4.1 and 4.4, so they have not "asm goto" support, which is required for jump label. I tried some ways to implement jump label without any modification of core implementation, but all are failed. My tries are focus on x86's arch_static_branch() modification. So far, I don't found out any good alternative solution of "asm goto" in old gcc. The last try is failed since its my implementation can't be invoked at same function multi times. The reason is GNU as does not assign different addresses on same symbol. My question, is possible to implement to jump label under such constraints? It's best to keep same interface with upstream tree. Any suggestions is welcome, thanks. Yu