From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Date: Fri, 24 Oct 2014 12:36:10 +0000 Subject: Re: [PATCH v9 09/12] x86, mpx: decode MPX instruction to get bound violation information Message-Id: List-Id: References: <1413088915-13428-1-git-send-email-qiaowei.ren@intel.com> <1413088915-13428-10-git-send-email-qiaowei.ren@intel.com> In-Reply-To: <1413088915-13428-10-git-send-email-qiaowei.ren@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Qiaowei Ren Cc: "H. Peter Anvin" , Ingo Molnar , Dave Hansen , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@linux-mips.org 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. Thanks, tglx