From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f172.google.com (mail-pd0-f172.google.com [209.85.192.172]) by kanga.kvack.org (Postfix) with ESMTP id 593236B0069 for ; Sun, 26 Oct 2014 21:45:54 -0400 (EDT) Received: by mail-pd0-f172.google.com with SMTP id r10so4664804pdi.31 for ; Sun, 26 Oct 2014 18:45:54 -0700 (PDT) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTP id j5si9353014pdk.48.2014.10.26.18.45.52 for ; Sun, 26 Oct 2014 18:45:53 -0700 (PDT) From: "Ren, Qiaowei" Subject: RE: [PATCH v9 09/12] x86, mpx: decode MPX instruction to get bound violation information Date: Mon, 27 Oct 2014 01:43:00 +0000 Message-ID: <9E0BE1322F2F2246BD820DA9FC397ADE0180ED16@shsmsx102.ccr.corp.intel.com> References: <1413088915-13428-1-git-send-email-qiaowei.ren@intel.com> <1413088915-13428-10-git-send-email-qiaowei.ren@intel.com> In-Reply-To: Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 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 2014-10-24, Thomas Gleixner wrote: > On Sun, 12 Oct 2014, Qiaowei Ren wrote: >=20 >> This patch sets bound violation fields of siginfo struct in #BR >> exception handler by decoding the user instruction and constructing >> the faulting pointer. >>=20 >> 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. >=20 > 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. >=20 As hpa said, we only need to decode several mpx instructions including BNDC= L/BNDCU, and general decoder looks like a little heavy. Peter, what do you = think about it? 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