From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3scwGc6vN7zDsf0 for ; Mon, 19 Sep 2016 16:00:24 +1000 (AEST) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8J5wpPu117096 for ; Mon, 19 Sep 2016 02:00:22 -0400 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0b-001b2d01.pphosted.com with ESMTP id 25gyyuubt4-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 19 Sep 2016 02:00:22 -0400 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 19 Sep 2016 00:00:21 -0600 From: "Aneesh Kumar K.V" To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH RESEND] powerpc: fix usage of _PAGE_RO in hugepage In-Reply-To: <20160916070227.DC69C1A2463@localhost.localdomain> References: <20160916070227.DC69C1A2463@localhost.localdomain> Date: Mon, 19 Sep 2016 11:30:12 +0530 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87k2e8xwcz.fsf@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Christophe Leroy writes: > On some CPUs like the 8xx, _PAGE_RW hence _PAGE_WRITE is defined > as 0 and _PAGE_RO has to be set when a page is not writable > > _PAGE_RO is defined by default in pte-common.h, however BOOK3S/64 > doesn't include that file so _PAGE_RO has to be defined explicitly > in book3s/64/pgtable.h > > fixes: a7b9f671f2d14 ("powerpc32: adds handling of _PAGE_RO") > Signed-off-by: Christophe Leroy > --- > This patch was initially part of the v1 serie of patchs for providing > hugepage support to the 8xx. As suggested by Aneesh, that serie has > been splited to focus only on hugepage implementation for 8xx. > This patch is a fix and is independant of 8xx hugepage implementation, > allthough it is required to have hugepage support working properly on > the 8xx. > > arch/powerpc/include/asm/book3s/64/pgtable.h | 2 ++ > arch/powerpc/mm/hugetlbpage.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index 8ec8be9..9fd77f8 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -6,6 +6,8 @@ > */ > #define _PAGE_BIT_SWAP_TYPE 0 > > +#define _PAGE_RO 0 > + > #define _PAGE_EXEC 0x00001 /* execute permission */ > #define _PAGE_WRITE 0x00002 /* write access allowed */ > #define _PAGE_READ 0x00004 /* read access allowed */ > diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c > index 7372ee1..8a512b1 100644 > --- a/arch/powerpc/mm/hugetlbpage.c > +++ b/arch/powerpc/mm/hugetlbpage.c > @@ -1021,6 +1021,8 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, > mask = _PAGE_PRESENT | _PAGE_READ; > if (write) > mask |= _PAGE_WRITE; > + else > + mask |= _PAGE_RO; > > if ((pte_val(pte) & mask) != mask) > return 0; > -- Can you add the commit message also as code comment ?. It is confusing to find that we do mask = _PAGE_READ and then mask |= _PAGE_RO. Otherwise Reviewed-by: Aneesh Kumar K.V -aneesh