From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751674AbeBVVwt (ORCPT ); Thu, 22 Feb 2018 16:52:49 -0500 Received: from mga18.intel.com ([134.134.136.126]:35397 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359AbeBVVws (ORCPT ); Thu, 22 Feb 2018 16:52:48 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,380,1515484800"; d="scan'208";a="19718524" Subject: Re: [RFC][PATCH 05/10] x86/mm: do not auto-massage page protections To: Nadav Amit References: <20180222203651.B776810C@viggo.jf.intel.com> <20180222203700.3FDE6BFD@viggo.jf.intel.com> <5659D3EF-CF51-4B1B-8306-CA2559A75789@vmware.com> Cc: "linux-kernel@vger.kernel.org" , "aarcange@redhat.com" , "luto@kernel.org" , "torvalds@linux-foundation.org" , "keescook@google.com" , "hughd@google.com" , "jgross@suse.com" , "x86@kernel.org" From: Dave Hansen Message-ID: <754bf1d5-759b-0162-98ae-1800f075b8eb@linux.intel.com> Date: Thu, 22 Feb 2018 13:52:47 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <5659D3EF-CF51-4B1B-8306-CA2559A75789@vmware.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/22/2018 01:46 PM, Nadav Amit wrote: >> >> +static inline pgprotval_t check_pgprot(pgprot_t pgprot) >> +{ >> + pgprotval_t massaged_val = massage_pgprot(pgprot); >> + >> + WARN_ONCE(pgprot_val(pgprot) != massaged_val, >> + "attempted to set unsupported pgprot: %016lx " >> + "bits: %016lx supported: %016lx\n", >> + pgprot_val(pgprot), >> + pgprot_val(pgprot) ^ massaged_val, >> + __supported_pte_mask); > Perhaps use VM_WARN_ONCE instead to avoid any overhead on production > systems? Sounds sane enough. I'll change it.