From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3qdwBz2FD4zDq6C for ; Tue, 5 Apr 2016 01:00:11 +1000 (AEST) Received: from localhost by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 5 Apr 2016 01:00:09 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 2D5363578057 for ; Tue, 5 Apr 2016 01:00:00 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u34ExqXl66846782 for ; Tue, 5 Apr 2016 01:00:00 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u34ExR2f028580 for ; Tue, 5 Apr 2016 00:59:27 +1000 From: "Aneesh Kumar K.V" To: Balbir Singh , benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 03/65] powerpc/mm/subpage: Clear RWX bit to indicate no access In-Reply-To: <56FC808B.7030704@gmail.com> References: <1459067053-10835-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1459067053-10835-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <56FC808B.7030704@gmail.com> Date: Mon, 04 Apr 2016 20:29:08 +0530 Message-ID: <87pou5xvwj.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Balbir Singh writes: > [ text/plain ] > > > On 27/03/16 19:23, Aneesh Kumar K.V wrote: >> Subpage protection used to depend on _PAGE_USER bit to implement no >> access mode. This patch switch that to use _PAGE_RWX. We clear READ, >> Write and Execute access from pte instead of clearing _PAGE_USER now. >> This was done so that we can switch to _PAGE_PRIVILEGED in later patch. >> subpage_protection() returns pte bits that need to be cleared. > Could you please clarify what bit needs to be cleared. I think the underlying > assumption is that when this routine is called access cannot be _PAGE_RWX I didn't follow the question. subpage_protection() returns the pte bits that need to be cleared for a specific access depending on the subpage prot mask we set using subpage_prot syscall. >> Instead of updating the interface to handle no-access in a separate way, >> it appears simple to clear RWX acecss to indicate no access. >> -aneesh