From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752614Ab2FEVvU (ORCPT ); Tue, 5 Jun 2012 17:51:20 -0400 Received: from mga01.intel.com ([192.55.52.88]:63093 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751187Ab2FEVvT (ORCPT ); Tue, 5 Jun 2012 17:51:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="175219751" From: Andi Kleen To: Masami Hiramatsu Cc: Steven Rostedt , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Ananth N Mavinakayanahalli , "Frank Ch. Eigler" , Andrew Morton , Frederic Weisbecker , yrl.pp-manager.tt@hitachi.com Subject: Re: [PATCH -tip v2 3/9] ftrace/x86: Support SAVE_REGS feature on i386 References: <20120605102734.27845.43401.stgit@localhost.localdomain> <20120605102802.27845.49309.stgit@localhost.localdomain> Date: Tue, 05 Jun 2012 14:51:18 -0700 In-Reply-To: <20120605102802.27845.49309.stgit@localhost.localdomain> (Masami Hiramatsu's message of "Tue, 05 Jun 2012 19:28:02 +0900") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Masami Hiramatsu writes: > > + .macro FTRACE_SAVE_ALL > + /* eflags is saved on cs */ > + subl $8, %esp /* skip ip and orig_ax */ > + pushl %gs > + pushl %fs For pure in kernel use you don't need to save/restore fs/gs This is only needed on kernel/user space boundaries. And for this usage probably also not flags -Andi -- ak@linux.intel.com -- Speaking for myself only