From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f176.google.com (mail-pd0-f176.google.com [209.85.192.176]) by kanga.kvack.org (Postfix) with ESMTP id CED146B0035 for ; Thu, 11 Sep 2014 18:35:49 -0400 (EDT) Received: by mail-pd0-f176.google.com with SMTP id y13so10514200pdi.21 for ; Thu, 11 Sep 2014 15:35:49 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [2001:1868:205::10]) by mx.google.com with ESMTPS id ns9si4078000pdb.221.2014.09.11.15.35.48 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Sep 2014 15:35:48 -0700 (PDT) Message-ID: <541223B1.5040705@zytor.com> Date: Thu, 11 Sep 2014 15:35:29 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH v8 07/10] x86, mpx: decode MPX instruction to get bound violation information References: <1410425210-24789-1-git-send-email-qiaowei.ren@intel.com> <1410425210-24789-8-git-send-email-qiaowei.ren@intel.com> <5412230A.6090805@intel.com> In-Reply-To: <5412230A.6090805@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen , Thomas Gleixner , Qiaowei Ren Cc: Ingo Molnar , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 09/11/2014 03:32 PM, Dave Hansen wrote: > On 09/11/2014 03:18 PM, Thomas Gleixner wrote: >> On Thu, 11 Sep 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. >> >> And why is that an argument to add another special purpose decoder? > > Peter asked for it to be done this way specifically: > > https://lkml.org/lkml/2014/6/19/411 > Specifically because marshaling the data in and out of the generic decoder was more complex than a special-purpose decoder. -hpa -- 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