From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 643C0C04FF3 for ; Sat, 22 May 2021 01:58:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4597F60C3E for ; Sat, 22 May 2021 01:58:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230500AbhEVB7m (ORCPT ); Fri, 21 May 2021 21:59:42 -0400 Received: from mga03.intel.com ([134.134.136.65]:6339 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230371AbhEVB7l (ORCPT ); Fri, 21 May 2021 21:59:41 -0400 IronPort-SDR: tHeQdk5oT7sL4UaAgu8mD6ZspjcLNbF8qkxf1f1A7erTV42XuBd3g7fxtKwZOh9msq3p3vo3W5 usx89uXfcvww== X-IronPort-AV: E=McAfee;i="6200,9189,9991"; a="201660914" X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="201660914" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2021 18:58:16 -0700 IronPort-SDR: IS1a1WjJpDP/oMTDY7yRQl6/vLIwFp04ZRQAZ3ziPozZVC+dJYHKaJK5SF3eo2OzyVejVGMg9A Ua3eWG277zeg== X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="395558527" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.254.177.76]) ([10.254.177.76]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2021 18:58:14 -0700 Subject: Re: [PATCH v27 13/31] mm: Move VM_UFFD_MINOR_BIT from 37 to 38 To: Axel Rasmussen Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , LKML , linux-doc@vger.kernel.org, Linux MM , linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang , Peter Xu References: <20210521221211.29077-1-yu-cheng.yu@intel.com> <20210521221211.29077-14-yu-cheng.yu@intel.com> From: "Yu, Yu-cheng" Message-ID: <74057265-c148-98bf-9ada-21328b160227@intel.com> Date: Fri, 21 May 2021 18:58:14 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/21/2021 3:25 PM, Axel Rasmussen wrote: > This seems reasonable to me. The particular bit used isn't so > important from my perspective. I can't think of a way this would break > backward compatibility or such. So: > > Reviewed-by: Axel Rasmussen Thanks! Yu-cheng > > On Fri, May 21, 2021 at 3:13 PM Yu-cheng Yu wrote: >> >> To introduce VM_SHADOW_STACK as VM_HIGH_ARCH_BIT (37), and make all >> VM_HIGH_ARCH_BITs stay together, move VM_UFFD_MINOR_BIT from 37 to 38. >> >> Signed-off-by: Yu-cheng Yu >> Cc: Axel Rasmussen >> Cc: Peter Xu >> Cc: Mike Kravetz >> --- >> include/linux/mm.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index c274f75efcf9..923f89b9f1b5 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -373,7 +373,7 @@ extern unsigned int kobjsize(const void *objp); >> #endif >> >> #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR >> -# define VM_UFFD_MINOR_BIT 37 >> +# define VM_UFFD_MINOR_BIT 38 >> # define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */ >> #else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ >> # define VM_UFFD_MINOR VM_NONE >> -- >> 2.21.0 >>