Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753686AbaBUCvD (ORCPT ); Thu, 20 Feb 2014 21:51:03 -0500 Received: from mga11.intel.com ([192.55.52.93]:44751 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752899AbaBUCu7 (ORCPT ); Thu, 20 Feb 2014 21:50:59 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,516,1389772800"; d="scan'208";a="485232165" Message-ID: <5306BD8D.3030606@intel.com> Date: Fri, 21 Feb 2014 10:44:29 +0800 From: Ren Qiaowei User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: Andy Lutomirski , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar CC: x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/3] x86, mpx: hook #BR exception handler to allocate bound tables References: <1392230186-16130-1-git-send-email-qiaowei.ren@intel.com> <1392230186-16130-3-git-send-email-qiaowei.ren@intel.com> <52FBD74F.7050203@mit.edu> In-Reply-To: <52FBD74F.7050203@mit.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/13/2014 04:19 AM, Andy Lutomirski wrote: > On 02/12/2014 10:36 AM, Qiaowei Ren wrote: >> An access to an invalid bound directory entry will cause a #BR >> exception. This patch hook #BR exception handler to allocate >> one bound table and bind it with that buond directory entry. >> >> This will avoid the need of forwarding the #BR exception >> to the user space when bound directory has invalid entry. >> >> Signed-off-by: Qiaowei Ren >> --- >> +void do_mpx_bt_fault(struct xsave_struct *xsave_buf) >> +{ >> + unsigned long status; >> + unsigned long bd_entry, bd_base; >> + unsigned long bd_size = 1UL << (MPX_L1_BITS+MPX_L1_SHIFT); >> + >> + bd_base = xsave_buf->bndcsr.cfg_reg_u & MPX_BNDCFG_ADDR_MASK; >> + status = xsave_buf->bndcsr.status_reg; >> + >> + bd_entry = status & MPX_BNDSTA_ADDR_MASK; >> + if ((bd_entry >= bd_base) && (bd_entry < bd_base + bd_size)) >> + allocate_bt(bd_entry); >> +} > > This still just loops on failure, right? > Seems like that SIGBUS should be raised if the allocation fail. if (!do_mpx_bt_fault(xsave_buf)) force_sig(SIGBUS, tsk); Thanks, Qiaowei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/