From patchwork Thu Jan 15 08:58:28 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Borntraeger X-Patchwork-Id: 429295 X-Patchwork-Delegate: michael@ellerman.id.au Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 6B20C140295 for ; Thu, 15 Jan 2015 19:59:13 +1100 (AEDT) Received: from ozlabs.org (ozlabs.org [103.22.144.67]) by lists.ozlabs.org (Postfix) with ESMTP id 5168F1A0E57 for ; Thu, 15 Jan 2015 19:59:13 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from e06smtp17.uk.ibm.com (e06smtp17.uk.ibm.com [195.75.94.113]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 5AE6B1A0D7E for ; Thu, 15 Jan 2015 19:58:20 +1100 (AEDT) Received: from /spool/local by e06smtp17.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 15 Jan 2015 08:58:16 -0000 Received: from d06dlp02.portsmouth.uk.ibm.com (9.149.20.14) by e06smtp17.uk.ibm.com (192.168.101.147) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Thu, 15 Jan 2015 08:58:14 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 578C42190046 for ; Thu, 15 Jan 2015 08:57:41 +0000 (GMT) Received: from d06av05.portsmouth.uk.ibm.com (d06av05.portsmouth.uk.ibm.com [9.149.37.229]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t0F8wDAn62324944 for ; Thu, 15 Jan 2015 08:58:13 GMT Received: from d06av05.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t0F8wD6w009615 for ; Thu, 15 Jan 2015 01:58:13 -0700 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id t0F8wCdD009610; Thu, 15 Jan 2015 01:58:12 -0700 Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 25651) id D72D61224458; Thu, 15 Jan 2015 09:58:12 +0100 (CET) From: Christian Borntraeger To: linux-kernel@vger.kernel.org Subject: [PATCH 2/8] ppc/hugetlbfs: Replace ACCESS_ONCE with READ_ONCE Date: Thu, 15 Jan 2015 09:58:28 +0100 Message-Id: <1421312314-72330-3-git-send-email-borntraeger@de.ibm.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1421312314-72330-1-git-send-email-borntraeger@de.ibm.com> References: <1421312314-72330-1-git-send-email-borntraeger@de.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15011508-0029-0000-0000-000002D00B1B Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, Christian Borntraeger , x86@kernel.org, kvm-ppc@vger.kernel.org, linux-mm@kvack.org, xen-devel@lists.xenproject.org, linuxppc-dev@lists.ozlabs.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Change the ppc/hugetlbfs code to replace ACCESS_ONCE with READ_ONCE. Signed-off-by: Christian Borntraeger --- arch/powerpc/mm/hugetlbpage.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 5ff4e07..620d0ec 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -978,7 +978,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift */ pdshift = PUD_SHIFT; pudp = pud_offset(&pgd, ea); - pud = ACCESS_ONCE(*pudp); + pud = READ_ONCE(*pudp); if (pud_none(pud)) return NULL; @@ -990,7 +990,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift else { pdshift = PMD_SHIFT; pmdp = pmd_offset(&pud, ea); - pmd = ACCESS_ONCE(*pmdp); + pmd = READ_ONCE(*pmdp); /* * A hugepage collapse is captured by pmd_none, because * it mark the pmd none and do a hpte invalidate.