From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751109AbdAQEja (ORCPT ); Mon, 16 Jan 2017 23:39:30 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:55952 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750770AbdAQEj3 (ORCPT ); Mon, 16 Jan 2017 23:39:29 -0500 Date: Mon, 16 Jan 2017 23:39:24 -0500 (EST) Message-Id: <20170116.233924.374841184595409216.davem@davemloft.net> To: khalid.aziz@oracle.com Cc: corbet@lwn.net, viro@zeniv.linux.org.uk, nitin.m.gupta@oracle.com, mike.kravetz@oracle.com, akpm@linux-foundation.org, mingo@kernel.org, kirill.shutemov@linux.intel.com, adam.buchbinder@gmail.com, hughd@google.com, minchan@kernel.org, keescook@chromium.org, chris.hyser@oracle.com, atish.patra@oracle.com, cmetcalf@mellanox.com, atomlin@redhat.com, jslaby@suse.cz, joe@perches.com, paul.gortmaker@windriver.com, mhocko@suse.com, lstoakes@gmail.com, jack@suse.cz, dave.hansen@linux.intel.com, vbabka@suse.cz, dan.j.williams@intel.com, iamjoonsoo.kim@lge.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, khalid@gonehiking.org Subject: Re: [PATCH v4 4/4] sparc64: Add support for ADI (Application Data Integrity) From: David Miller In-Reply-To: <0c08eb00e5a9735d7d0bcbeaadeacaa761011aab.1483999591.git.khalid.aziz@oracle.com> References: <0c08eb00e5a9735d7d0bcbeaadeacaa761011aab.1483999591.git.khalid.aziz@oracle.com> X-Mailer: Mew version 6.7 on Emacs 25.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 16 Jan 2017 19:40:21 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Khalid Aziz Date: Wed, 11 Jan 2017 09:12:54 -0700 > + __asm__ __volatile__( > + ".word 0xa1438000\n\t" /* rd %mcdper, %l0 */ Just use "rd %%asr14, %0" this way you don't have to play all of these fixed register games which kill the code generated by gcc. If you forcefully clobber a windowed register like %l0 it means the function being emitted can never be a leaf function, tail calls are no longer allowed, etc. > + ".word 0x9d800011\n\t" /* wr %g0, %l1, %mcdper */ Likewise use "wr %%g0, %0, %%asr14" > + ".word 0xaf900001\n\t" /* wrpr %g0, %g1, %pmcdper */ Hmmm, which %asr encodes %pmcdper? > diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c > index 8a6982d..68b03bf 100644 > --- a/arch/sparc/kernel/mdesc.c > +++ b/arch/sparc/kernel/mdesc.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > /* Unlike the OBP device tree, the machine description is a full-on > * DAG. An arbitrary number of ARCs are possible from one > @@ -1104,5 +1105,8 @@ void __init sun4v_mdesc_init(void) > > cur_mdesc = hp; > > +#ifdef CONFIG_SPARC64 mdesc.c is only built on sparc64, this ifdef is superfluous. > +/* Update the state of MCDPER register in current task's mm context before > + * dup so the dup'd task will inherit flags in this register correctly. > + * Current task may have updated flags since it started running. > + */ > +int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) > +{ > + if (adi_capable() && src->mm) { > + register unsigned long tmp_mcdper; > + > + __asm__ __volatile__( > + ".word 0x83438000\n\t" /* rd %mcdper, %g1 */ > + "mov %%g1, %0\n\t" > + : "=r" (tmp_mcdper) > + : > + : "g1"); > + src->mm->context.mcdper = tmp_mcdper; I don't like the idea of duplicating 'mm' state using the task struct copy. Why do not the MM handling interfaces handle this properly? Maybe it means you've abstracted the ADI register handling in the wrong place. Maybe it's a thread property which is "pushed" from the MM context.