From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 806446B0033 for ; Mon, 16 Jan 2017 23:42:19 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id 5so111317944pgi.2 for ; Mon, 16 Jan 2017 20:42:19 -0800 (PST) Received: from shards.monkeyblade.net (shards.monkeyblade.net. [184.105.139.130]) by mx.google.com with ESMTP id b128si23615007pgc.336.2017.01.16.20.42.18 for ; Mon, 16 Jan 2017 20:42:18 -0800 (PST) Date: Mon, 16 Jan 2017 23:42:13 -0500 (EST) Message-Id: <20170116.234213.651609572218128435.davem@davemloft.net> Subject: Re: [PATCH v4 0/4] Application Data Integrity feature introduced by SPARC M7 From: David Miller In-Reply-To: <621cfed0-3e56-13e6-689a-0637bce164fe@linux.intel.com> References: <621cfed0-3e56-13e6-689a-0637bce164fe@linux.intel.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: dave.hansen@linux.intel.com Cc: khalid.aziz@oracle.com, corbet@lwn.net, arnd@arndb.de, akpm@linux-foundation.org, hpa@zytor.com, viro@zeniv.linux.org.uk, nitin.m.gupta@oracle.com, chris.hyser@oracle.com, tushar.n.dave@oracle.com, sowmini.varadhan@oracle.com, mike.kravetz@oracle.com, adam.buchbinder@gmail.com, minchan@kernel.org, hughd@google.com, kirill.shutemov@linux.intel.com, keescook@chromium.org, allen.pais@oracle.com, aryabinin@virtuozzo.com, atish.patra@oracle.com, joe@perches.com, pmladek@suse.com, jslaby@suse.cz, cmetcalf@mellanox.com, paul.gortmaker@windriver.com, mhocko@suse.com, jmarchan@redhat.com, lstoakes@gmail.com, 0x7f454c46@gmail.com, vbabka@suse.cz, tglx@linutronix.de, mingo@redhat.com, dan.j.williams@intel.com, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net, vdavydov.dev@gmail.com, hannes@cmpxchg.org, namit@vmware.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org From: Dave Hansen Date: Wed, 11 Jan 2017 08:33:30 -0800 > Is there a cost in the hardware associated with doing this "ADI > checking"? For instance, instead of having this new mprotect() > interface, why not just always set TTE.mcd on all PTEs? If we did this then for every page mapped into userspace we'd have to explicitly set all of the tags to zero, otherwise we'd get TAG mismatch exceptions. That would be like clearing the every mapped anonymous page twice, or worse. -- 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