From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f52.google.com (mail-pa0-f52.google.com [209.85.220.52]) by kanga.kvack.org (Postfix) with ESMTP id 5D9D2900021 for ; Tue, 28 Oct 2014 02:01:28 -0400 (EDT) Received: by mail-pa0-f52.google.com with SMTP id fa1so5344436pad.11 for ; Mon, 27 Oct 2014 23:01:28 -0700 (PDT) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTP id p1si393241pdp.169.2014.10.27.23.01.27 for ; Mon, 27 Oct 2014 23:01:27 -0700 (PDT) Message-ID: <544F307D.7090701@intel.com> Date: Tue, 28 Oct 2014 13:58:21 +0800 From: Ren Qiaowei MIME-Version: 1.0 Subject: Re: [PATCH v9 09/12] x86, mpx: decode MPX instruction to get bound violation information References: <1413088915-13428-1-git-send-email-qiaowei.ren@intel.com> <1413088915-13428-10-git-send-email-qiaowei.ren@intel.com> <9E0BE1322F2F2246BD820DA9FC397ADE0180ED16@shsmsx102.ccr.corp.intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner Cc: "H. Peter Anvin" , Ingo Molnar , "Hansen, Dave" , "x86@kernel.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "linux-ia64@vger.kernel.org" , "linux-mips@linux-mips.org" On 10/28/2014 04:36 AM, Thomas Gleixner wrote: > On Mon, 27 Oct 2014, Ren, Qiaowei wrote: >> On 2014-10-24, Thomas Gleixner wrote: >>> On Sun, 12 Oct 2014, Qiaowei Ren wrote: >>> >>>> This patch sets bound violation fields of siginfo struct in #BR >>>> exception handler by decoding the user instruction and constructing >>>> the faulting pointer. >>>> >>>> This patch does't use the generic decoder, and implements a limited >>>> special-purpose decoder to decode MPX instructions, simply because >>>> the generic decoder is very heavyweight not just in terms of >>>> performance but in terms of interface -- because it has to. >>> >>> My question still stands why using the existing decoder is an issue. >>> Performance is a complete non issue in case of a bounds violation and >>> the interface argument is just silly, really. >>> >> >> As hpa said, we only need to decode several mpx instructions >> including BNDCL/BNDCU, and general decoder looks like a little >> heavy. Peter, what do you think about it? > > You're repeating yourself. Care to read the discussion about this from > the last round of review again? > Ok. I will go through it again. Thanks. - Qiaowei -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org